Dissertations / Theses: 'Regional flux'

1

Cordova, Vicente D. "Regional-scale carbon flux estimation using MODIS imagery." Virtual Press, 2005. http://liblink.bsu.edu/uhtbin/catkey/1325989.

Full text

Abstract:

The National Aeronautics and Space Agency NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) platform carried by Terra and Aqua satellites, is providing systematic measurements summarized in high quality, consistent and well-calibrated satellite images and datasets ranging from reflectance in the visible and near infrared bands to estimates of leaf area index, vegetation indices and biome productivity. The objective of this research was to relate the spectral responses and derived MODIS products of ecosystems, to biogeochemical processes and trends in their physiological variables. When different sources of data were compared, discrepancies between the MODIS variables and the corresponding ground measurements were evident. Uncertainties in the input variables of MODIS products algorithms, effects of cloud cover at the studied pixel, estimation algorithm, and local variation in land cover type are considered as the cause. A simple "continuous field" model based on a physiologically-driven spectral index using two ocean-color bands of MODIS satellite sensor showed great potential to track seasonally changing photosynthetic light use efficiency and stress-induced reduction in net primary productivity of terrestrial vegetation. The model explained 88% of the variability in Flux tower-based daily Net Primary Productivity. Also a high correlation between midday gross CO2 exchange with both daily and 8-day mean gross CO2 exchange, consistent across all the studied vegetation types, was found. Although it may not be possible to estimate 8-day mean Light Use Efficiency reliably from satellite data, Light Use Efficiency models may still be useful for estimation of midday values of gross CO2 exchange which could then be related to longer term means of CO2 exchange. In addition, the MODIS enhanced vegetation index shows a high potential for estimation of ecosystem gross primary production, using respiration values from MODIS surface temperature, providing truly per-pixel estimates.
Department of Natural Resources and Environmental Management

APA, Harvard, Vancouver, ISO, and other styles

2

O'Shea, Sebastian James. "Airborne observations and regional flux estimates of greenhouse gases." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/airborne-observations-and-regional-flux-estimates-of-greenhouse-gases(9cc17627-8320-4ffd-9cf7-faf4688bf20d).html.

Full text

Abstract:

Methane is the second most important long-lived greenhouse gas. However, it is typically emitted to the atmosphere by spatially and temporally heterogeneous sources, meaning that local measurements cannot easily be extrapolated to represent global scales. As a consequence, its global sources and sinks are generally poorly quantified. This thesis focuses on the use of airborne observations to improve flux estimates of methane at regional scales. A commercially available cavity-enhanced absorption spectrometer has been modified here for airborne measurements of methane and carbon dioxide. An algorithm employing the system's simultaneous water vapour measurement has been derived, using laboratory experiments, to determine dry air mole fractions without the need for sample drying. The system was found to be relatively independent of the aircraft's motion and its measurements were found to be accurate to within 1.28 ppb (1 standard deviation repeatability at 1Hz of 2.48 ppb) for methane and 0.17 ppm (1 standard deviation repeatability at 1Hz of 0.66 ppm) for carbon dioxide. This new measurement capability has been deployed during three international field campaigns, data from which is used in this thesis. The composition of boreal biomass burning was measured in eastern Canada. Methane emission factors showed a high degree of variability (range 1.8 $\pm$\ 0.2 to 8.5 $\pm$\ 0.9 g (kg dry matter)$^{-1}$), accentuating the challenges with using a purely bottom-up approach to determine total methane emissions and that top-down constraints are needed. Two case studies have shown that an aircraft mass balance approach can be a valuable tool for deriving regional scale top-down flux estimates, when a suitable sampling strategy can be employed under appropriate atmospheric conditions. First, this technique was applied to the European Arctic wetlands; and second, its suitability to derive emissions from a megacity was investigated using London, UK as a test case. On both occasions, the derived fluxes were found to be in good agreement with coincident surface observations within the aircraft's sampling domain. In the case of the Arctic wetlands the excellent agreement with seasonally averaged surface observations allowed this information to be used for the evaluation of land surface models. Two commonly used models, the Joint UK Land Environment Simulator and Hybrid8 were found to underestimate the methane emission flux for this region by an order of magnitude, highlighting the large uncertainties present in future methane emission scenarios at regional scales under a changing climate.

APA, Harvard, Vancouver, ISO, and other styles

3

Yu, Yanling. "Regional Arctic ice thickness and brine flux from AVHRR /." Thesis, Connect to this title online; UW restricted, 1996. http://hdl.handle.net/1773/11067.

Full text

APA, Harvard, Vancouver, ISO, and other styles

4

Nickless, Alecia. "Regional CO₂ flux estimates for South Africa through inverse modelling." Doctoral thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/29703.

Full text

Abstract:

Bayesian inverse modelling provides a top-down technique of verifying emissions and uptake of carbon dioxide (CO₂) from both natural and anthropogenic sources. It relies on accurate measurements of CO₂ concentrations at appropriately placed sites and "best-guess" initial estimates of the biogenic and anthropogenic emissions, together with uncertainty estimates. The Bayesian framework improves current estimates of CO₂ fluxes based on independent measurements of CO₂ concentrations while being constrained by the initial estimates of these fluxes. Monitoring, reporting and verification (MRV) is critical for establishing whether emission reducing activities to mitigate the effects of climate change are being effective, and the Bayesian inverse modelling approach of correcting CO₂ flux estimates provides one of the tools regulators and researchers can use to refine these emission estimates. South Africa is known to be the largest emitter of CO₂ on the African continent. The first major objective of this research project was to carry out such an optimal network design for South Africa. This study used fossil fuel emission estimates from a satellite product based on observations of night-time lights and locations of power stations (Fossil Fuel Data Assimilations System (FFDAS)), and biogenic productivity estimates from a carbon assessment carried out for South Africa to provide the initial CO₂ flux estimates and their uncertainties. Sensitivity analyses considered changes to the covariance matrix and spatial scale of the inversion, as well as different optimisation algorithms, to assess the impact of these specifications on the optimal network solution. This question was addressed in Chapters 2 and 3. The second major objective of this project was to use the Bayesian inverse modelling approach to obtain estimates of CO₂ fluxes over Cape Town and surrounding area. I collected measurements of atmospheric CO₂ concentrations from March 2012 until July 2013 at Robben Island and Hangklip lighthouses. CABLE (Community Atmosphere Biosphere Land Exchange), a land-atmosphere exchange model, provided the biogenic estimates of CO₂ fluxes and their uncertainties. Fossil fuel estimates and uncertainties were obtained by means of an inventory analysis for Cape Town. As an inventory analysis was not available for Cape Town, this exercise formed an additional objective of the project, presented in Chapter 4. A spatially and temporally explicit, high resolution surface of fossil fuel emission estimates was derived from road vehicle, aviation and shipping vessel count data, population census data, and industrial fuel use statistics, making use of well-established emission factors. The city-scale inversion for Cape Town solved for weekly fluxes of CO₂ emissions on a 1 km × 1 km grid, keeping fossil fuel and biogenic emissions as separate sources. I present these results for the Cape Town inversion under the proposed best available configuration of the Bayesian inversion framework in Chapter 5. Due to the large number of CO₂ sources at this spatial and temporal resolution, the reference inversion solved for weekly fluxes in blocks of four weeks at a time. As the uncertainties around the biogenic flux estimates were large, the inversion corrected the prior fluxes predominantly through changes to the biogenic fluxes. I demonstrated the benefit of using a control vector with separate terms for fossil fuel and biogenic flux components. Sensitivity analyses, solving for average weekly fluxes within a monthly inversion, as well as solving for separate weekly fluxes (i.e. solving in one week blocks) were considered. Sensitivity analyses were performed which focused on how changes to the prior information and prior uncertainty estimates and the error correlations of the fluxes would impact on the Bayesian inversion solution. The sensitivity tests are presented in Chapter 6. These sensitivity analyses indicated that refining the estimates of biogenic fluxes and reducing their uncertainties, as well as taking advantage of spatial correlation between areas of homogeneous biota would lead to the greatest improvement in the accuracy and precision of the posterior fluxes from the Cape Town metropolitan area.

APA, Harvard, Vancouver, ISO, and other styles

5

Felippe, Monica Tais Siqueira D'Amelio. "Estudo de fluxo de óxido nitroso (N2O) regional na Bacia Amazônica." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-12082011-145420/.

Full text

Abstract:

O óxido nitroso (N2O) é o terceiro mais importante gás de efeito estufa. Globalmente, a maior fonte de N2O são os processos de nitrificação e desnitrificação no solo. Cerca de dois terços da emissão do solo ocorrem nos trópicos e aproximadamente 20% são originados nos ecossistemas de florestas tropicais úmidas, como a Floresta Amazônica. O presente estudo envolveu a realização de medidas de perfis verticais de N2O utilizando aviões de pequeno porte desde a superfície até cerca de 4 km sobre duas florestas da região leste e central da Amazônia: Flona Tapajós (2000-2009) e Rebio Cuieiras (2004-2007); e a estimativa dos fluxos de N2O da região entre a costa brasileira e as florestas acima mencionadas utilizando dois métodos de cálculo de fluxo: Método de Integração de Coluna e Modelo de Inversão FLEXPART. As medidas de N2O em escala regional até o presente momento são únicas e representam uma nova abordagem nas emissões nesta escala. Pelos dois métodos, o fluxo calculado entre a costa brasileira e a Rebio Cuieiras apresentou pouca sazonalidade e valor médio de 1,9±1,6 mgN2Om2dia1 para o Método de Integração de Coluna e 2,3±0,9 mgN2Om2dia1 para o Modelo de Inversão Flexpart. Para a região entre a costa e a Flona Tapajós, o Modelo de Inversão - FLEXPART apresentou cerca da metade (0,9±1,7 mgN2Om2dia1) do valor do fluxo de N2O calculado pelo Método de Integração de Coluna (2,0±1,1 mgN2Om2dia1) no mesmo período (2004-2008). Uma provável explicação é a não representatividade de atividades antrópicas pelo modelo de inversão, uma vez que este representou bem uma região menos impactada. As duas regiões estudadas apresentaram emissão de N2O semelhante na estação chuvosa. Pelo Método de Integração de Coluna a região entre a costa e a Flona Tapajós apresentou fluxo de N2O durante a estação seca (1,8±0,9 mgN2Om2dia1) muito próximo do fluxo calculado na estação chuvosa. Encontrou-se uma correlação entre os perfis de N2O ii e CO, traçador de queimadas, sendo esta uma das possíveis causas desta emissão. A taxa CO:N2O encontrada para os 38 perfis amostrados nesta estação foi de 82±69 mol CO:molN2O, cerca de 10 vezes maior que o apresentado em literaturas anteriores.
Nitrous oxide (N2O) is the third most important anthropogenic greenhouse gas. Globally, the main sources of N2O are nitrification and denitrification in soils. About two thirds of the soil emissions occur in the tropics and approximately 20% originate in wet rainforest ecosystems, like the Amazon forest. The work presented here involves aircraft vertical profiles of N2O from the surface to 4 km over two sites in the Eastern and Central Amazon: Tapajós National Forest (2000-2009) and Cuieiras Biologic Reserve (2004-2007), and the estimation of N2O fluxes for regions upwind of these sites using two methods: Column Integration Technique and Inversion Model FLEXPART. To our knowledge, these regional scale N2O measurements in Amazonia are unique and represent a new approach to looking regional scale emissions. For the both methods, the fluxes upwind of Cuieiras Biologic Reserve exhibited little seasonality, and the annual mean was 1.9±1.6 mgN2Om2day1 for the Column Integration Technique and 2.3±0.9 mgN2Om2day1 for Inversion Model - FLEXPART. For fluxes upwind of Tapajós Nacional Forest, the Inversion Model - FLEXPART presented about half (0.9±1.7 mgN2Om2day1) of the Column Integration Technique (2.0±1.1 mgN2Om2day1) for the same period (2004-2008). One reason could be because the inversion model does not consider anthropic activities, once it had a good representation for less impacted area. Both reagions presented similar emission during wet season. By Column Integration Technique, fluxes upwind Tapajós Nacional Forest were similar for dry and wet seasons. The dry season N2O fluxes exhibit significant correlations with CO fluxes, indicating a larger than expected source of N2O from biomass burning. The average CO:N2O ratio for all 38 profiles sampled during the dry season was 82±69 mol CO:molN2O and suggests a larger biomass burning contribution to the global N2O budget than previously reported.

APA, Harvard, Vancouver, ISO, and other styles

6

Styles, Julie Maree, and julie styles@oregonstate edu. "Inverse Modelling of Trace Gas Exchange at Canopy and Regional Scales." The Australian National University. Research School of Biological Sciences, 2003. http://thesis.anu.edu.au./public/adt-ANU20030905.040030.

Full text

Abstract:

This thesis deals with the estimation of plant-atmosphere trace gas exchange and isotopic discrimination from atmospheric concentration measurements. Two space scales were investigated: canopy and regional. The canopy-scale study combined a Lagrangian model of turbulent dispersal with ecophysiological principles to infer vertical profiles of fluxes of CO2, H2O and heat as well as carbon and oxygen isotope discrimination during CO2 assimilation, from concentration measurements within a forest. The regional-scale model used a convective boundary layer budget approach to infer average regional isotopic discrimination and fluxes of CO2 and sensible and latent heat from the evolution during the day of boundary layer height and mean concentrations of CO2 and H2O, temperature and carbon and oxygen isotope composition of CO2. For the canopy study, concentrations of five scalar quantities, CO2, 13CO2, C18O16O, H2O and temperature, were measured at up to nine heights within and above a mixed fir and spruce forest in central Siberia over several days just after snow melt in May 2000. Eddy covariance measurements of CO2, H2O and heat fluxes were made above the canopy over the same period, providing independent verification of the model flux estimates. Photosynthesis, transpiration, heat exchange and isotope discrimination during CO2 assimilation were modelled for sun and shade leaves throughout the canopy through a combination of inversion of the concentration data and principles of biochemistry, plant physiology and energy balance. In contrast to the more usual inverse modelling concept where fluxes are inferred directly from concentrations, in this study the inversion was used to predict unknown parameters within a process-based model of leaf gas and energy exchange. Parameters relating to photosynthetic capacity, stomatal conductance, radiation penetration and turbulence structure were optimised by the inversion to provide the best fit of modelled to measured concentration profiles of the five scalars. Model results showed that carbon isotope discrimination, stomatal conductance and intercellular CO2 concentration were depressed due to the low temperatures experienced during snow melt, oxygen isotope discrimination was positive and consistent with other estimates, radiation penetrated further than simple theoretical predictions because of leaf clumping and penumbra, the turbulence coherence was lower than expected and stability effects were important in the morning and evening. For the regional study, five flights were undertaken over two days in and above the convective boundary layer above a heterogeneous pine forest and bog region in central Siberia. Vertical profiles of CO2 and H2O concentrations, temperature and pressure were obtained during each flight. Air flask samples were taken at various heights for carbon and oxygen isotopic analysis of CO2. Two budget methods were used to estimate regional surface fluxes of CO2 and plant isotopic discrimination against 13CO2 and C18O16O, with the first method also used to infer regional sensible and latent heat fluxes. Flux estimates were compared to ground-based eddy covariance measurements. Model results showed that afternoon estimates for carbon and oxygen isotope discrimination were close to those expected from source water isotopic measurements and theory of isotope discrimination. Estimates for oxygen isotope discrimination for the morning period were considerably different and could be explained by contrasting influences of the two different ecosystem types and non-steady state evaporative enrichment of leaf water.

APA, Harvard, Vancouver, ISO, and other styles

7

FELIPPE, MONICA T. S. D. "Estudo de fluxo de oxido nitroso (Nsub(2)O) regional na bacia amazonica." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9547.

Full text

Abstract:

Made available in DSpace on 2014-10-09T12:27:52Z (GMT). No. of bitstreams: 0
Made available in DSpace on 2014-10-09T14:04:48Z (GMT). No. of bitstreams: 0
Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

APA, Harvard, Vancouver, ISO, and other styles

8

Kountouris, Panagiotis [Verfasser], Uwe Gutachter] Totsche, and Christoph [Gutachter] [Gerbig. "Regional carbon balance : flux optimization and network design / Panagiotis Kountouris ; Gutachter: Uwe Totsche, Christoph Gerbig." Jena : Friedrich-Schiller-Universität Jena, 2017. http://d-nb.info/1177600730/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

9

Zavarsky, Alexander [Verfasser]. "Eddy covariance air-sea gas flux measurements. Regional sources and gas transfer limitation / Alexander Zavarsky." Kiel : Universitätsbibliothek Kiel, 2018. http://d-nb.info/1167236807/34.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Vilanova, Muset Ester. "Anàlisi dels sistemes de flux a l'àrea Gavarres-Selva-Baix Empordà. Proposta de model Hidrodinàmic regional." Doctoral thesis, Universitat Autònoma de Barcelona, 2004. http://hdl.handle.net/10803/3437.

Full text

Abstract:

En la present tesi s'exposa una síntesi de la hidrogeologia del massís de les Gavarres i zones adjacents amb l'objectiu final d'identificar i descriure'n la dinàmica, ampliant el coneixement hidrogeològic d'aquesta zona sotmesa a una creixent demanda i avaluant la disponibilitat de recursos hídrics. Concretament, l'estudi hidrogeològic defineix i descriu les formacions hidrogeològiques locals, les seves àrees de recàrrega i els sistemes de flux que es produeixen acompanyant-ho de diverses cartografies piezomètriques. Addicionalment, es caracteritza la dinàmica del sistema mitjançant l'estudi de les fàcies hidroquímiques i de les dotacions en isòtops estables i radiogènics (d18O, dD, 3H, d13C, 87Sr/86Sr) que permeten integrar-les en un sistema hidrogeològic regional. Els resultats es corroboren amb una anàlisi multivariable, consistent en l'anàlisi de components principals, i amb un estudi de mescla de membres extrems. També, s'estudien les fonts riques en CO2 o "picants" mitjançant un seguiment de cabal i hidroquímic, amb la finalitat d'afinar el model conceptual hidrològic derivat de les dades anteriors integrant-hi aquests elements singulars del sistema.
El desenvolupament de la tesi ha permès identificar dos sistemes principals de flux com a origen de la recàrrega del sistema. Es descriu un sistema de caràcter local representat per la recàrrega procedent del massís de les Gavarres, que s'estableix en sentit divergent de d'aquest, el qual es fa present a la zona del Baix Ter i a la Vall d'Aro, així com a algunes captacions del marge oriental de la depressió de la Selva. Es de tipus pistó governat per fractures locals i adopta un sentit vertical ascendent a la zona nord a través de les formacions paleògenes. S'estimen els temps de residència en base al contingut en triti segons un model de desintegració i s'obtenen temps de trànsit d'entre 20-30 anys. En base als isòtops estables es determina l'estacionalitat de la recàrrega i s'avalua el percentatge de la precipitació infiltrant (10-15%) mitjançant mètodes hidroquímics. El segon sistema de flux que es constata és d'àmbit regional. Aquest es manifesta en les captacions més profundes de la depressió de la Selva, s'indueix antròpicament a les formacions sedimentàries soprajacents i ve governat per fractures regionals que delimiten les unitats morfoestructurals. Presenta característiques hidroquímiques diferenciades com a conseqüència de la interacció amb la roca sota elevats temps de residència, majors a 50 anys, segons indica el contingut en triti. La dotació en isótops estables suggereix una àrea de recàrrega que se situa a la serralada Transversal i/o en el massís de les Guilleries.
En les fonts riques en CO2 es constata la presència d'ambdós sistemes de flux els quals s'hi mesclen en diferents proporcions. Es considera que el sistema de flux local s'incorpora al cabal de les fonts amb posterioritat a l'addició del gas diluint les elevades mineralitzacions de l'aigua que s'atribueixen a la presència del gas. Al sistema regional es constata amb una major constància quantitativa i qualitativa.
L'anàlisi de components principals i l'estudi de la mescla de membres extrems corroboren la dinàmica hidrogeològica descrita mitjançant l'estudi multisotòpic. En concret, senyalen el domini de les reaccions silicatades i les influencies menors d'altres processos relacionats amb heterogeneïtats locals del medi, inducció antròpica de fluxos i mescla amb sistemes superficials. Concretament, a la zona del Baix Ter es caracteritza el sistema de flux dominant procedent de les gavarres que s'estableix en sentit vertical ascendent a la depressió i localment s'estimen les aportacions d'un flux influenciat per elevats cabals d'extracció procedent del riu Ter i intrusió salina. Els resultats manifesten l'aplicabilitat d'ambdós mètodes així com les seves limitacions.
Finalment l'estudi manifesta el paper de les fractures en el control dels sistemes de flux i de la recàrrega que afavoreixen l'aportació d'aigües amb temps de residència molt elevats i l'establiment de fluxos de sentit vertical ascendent. També, planteja la dinàmica del sistema a una escala regional considerant que les aportacions subterrànies procedents de les formacions hidrogeològiques profundes contribueixen notablement a les aportacions i als recursos disponibles.
This dissertation is focused on the hydrogeology of the Gavarres range and the surrounding basins of Selva and Baix Empordà. Its main objective consists on describing the hydrodynamics of the system based on geological field work, potentiometric data, hydrochemistry as well as isotopic data ((d18O, dD, 3H, d13C, 87Sr/86Sr). The purpose is to determine a conceptual model that describes the main flow systems of the area as a useful tool to define future exploitation criteria for those related aquifers. The occurrence of rich-CO2 cold springs in the area provides an opportunity to investigate a specific hydrological behavior and are studied as a singular points of the hydrogeological system.
This research has pointed out the existence of two main flow systems: a local system flow with recharge area in the Gavarres range and a regional system flow with longer flow paths from the Transversal and/or Guilleries range. The data results are summarized as follows.
The study identifies and characterizes different hydrogeological formations and potentiometric data show a divergent flux from the Gavarres range towards the sourronding basins. Hydraulic head data also indicates the influence of fractures in the local flow system and a vertical ascending recharge is suggested in the north basin. Furthermore, hydrochemical data supports potentiometric observations and also suggests different residence times depending on flow path. The local meteoric line obtained from rainfall stable isotopes indicates seasonal recharge and its positions respect groundwater samples suggests different dynamics and recharge area in Empordà and Selva basins. Gavarres is the main recharge area but in deepest points of south basin a different and higher recharge areas are considered. CO2-rich springs also agree with these observations despite a modification of its d18O contents because of CO2 exsolution. According to the geological setting, those recharge areas would be located at the Transversal and Guilleries range, which bound the Selva basin in its northern and western boundaries. Tritium content points out different residence times of water samples. Two different groups of tritium data are distinguished, which correlates with the observed differences using stable isotopes, one infiltrated before 1952 occurs at the deepest wells of the Selva basin and at the CO2-rich springs, and is related to a regional flow system. The high exploitation rate in this basin induces flow from this deep regional system to arkosic basin materials. A second, modern set of data which would enter the system 20 years ago is described in Empordà and Aro basin as well as in shallow aquifers in Selva basin. Strontium content and 87Sr/86Sr ratios are used to tracer the flow path and the isotopic content. In particular, Empordà aquifers show a radiogenic signature acquired in the local metamorphic recharge area supporting the existence of vertical upwelling flow.
Principal component analysis (PCA) allows statistical grouping that reflects bedrock lithology and supports some of the identified chemical reactions. Subsequently, end-member mixing analysis has been applied to the Baix Empordà samples to verify mixing rates between the Gavarres recharge through the paleogene aquifers, the Ter river capture and salt water intrusion. Despite that the method needs to be carefully checked for consistency, its application to water samples from the alluvial aquifer demonstrates the major recharge from the underlying paleogene formations, a Ter river participation of about 20%, and a maximum percentage of 10% of salt water in specific wells.
In conclusion, the study of the hydrogeology of the Gavarres-Selva-Baix Empordà system has pictured two distinct flow systems with different chemical and isotopic content and characterized by different dynamics. Furthermore, it shows that the Gavarres range only acts as a local recharge area, and that groundwater from the Selva basin also gets its inflow from distant areas, namely the Transversal and Guilleries ranges.

APA, Harvard, Vancouver, ISO, and other styles

11

Pereira, Ana Paula Camilo [UNESP]. "Transporte Aéreo Regional no Estado de São Paulo." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/96744.

Full text

Abstract:

Made available in DSpace on 2014-06-11T19:28:26Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-01-18Bitstream added on 2014-06-13T18:34:35Z : No. of bitstreams: 1 pereira_apc_me_prud.pdf: 2173490 bytes, checksum: 9598db07e769e12b318a704645af3c0d (MD5)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O presente trabalho propõe-se a uma reflexão sobre o transporte aéreo regional no Estado de São Paulo. Considera-se, para isso, que as cidades constituem elos entre os setores de produtividade e consumo, por representarem nós de rede urbana, além de definirem a desconcentração urbano-industrial no Estado. Assim, as cidades estão inseridas em uma rede de relações sociais e econômicas e possuem importante função na organização da circulação do território e na produção do espaço urbano. O modal aéreo possibilita uma maior fluidez territorial, o que torna mais flexível a superação do espaço pelo tempo. O imperativo da sociedade atual, influenciado pelo meio técnico-científico-informacional e pelas invenções e inovações tecnológicas, exige uma mobilidade que remete a uma perspectiva intensamente renovadora dos meios de transporte. O transporte aéreo requer infraestruturas adequadas, ou seja, os fluxos demandam fixos produtivos que balizem seu movimento, assim como necessita de planejamento, regulamentação e organização do seu mercado. Nesse sentido, apresentamos nesta pesquisa uma análise geoeconômica dos fluxos aéreos no interior do Estado de São Paulo, tendo como referencial, primeiramente, uma abordagem evolucionista do setor no Brasil, que caracteriza a sua atual situação. Em seguida, relatamos como o modal tem se desenvolvido no Estado de São Paulo, considerando a processualidade dos fatores relacionados à dinâmica dos fluxos aéreos de passageiros entre os aeroportos na interface com a capital paulista, que tem obtido um constante crescimento...
Ce travail se propose à une réflexion au transport aérien régional l‟état de São Paulo. On considère, pour cela, que les villes constituent des liens entre les secteurs de productivité et consommations, puisqu‟ils réprésentent des noeuds du réseau urbain ; en plus, ils définent la déconcentration urbaine-industrielle dans l‟état. Ainsi, les cités sont inserées dans un réseau de rapports sociaux et économiques et ont d‟importante fonction dans l‟aménagement de la circulation du territoire et dans les productions de l‟espace urbain. Le modal aérien possibilite une plus grande fluidité territoriale, ce qui rend plus flexible la supération de l‟espace par le temps. L‟impératif de la société actuelle, influencé par le moyen technique-cientifique-informationnel et par les inventions et les inovations technologiques, demande une mobilité qui fait appel à une perspective intensement renovatrice des moyens de transport. Le transport aérien demande de l‟infrastructure adéquate, c‟est-à-dire, les flux demandent des fixes productifs qui conduisent leur mouvement, bien qu‟il a besoin de projetement, reglémentation e aménengement de leur marché. Dans ce sens, nous présentons dans cette recherche une analyse géoéconomique des flux aériens à l‟intérieur de l‟état de São Paulo, ayant comme référentiel, d‟abord, une approche evolutioniste du secteur au Brésil, qui caractérise la situation actuelle. À la suíte, nous racontons comme le modal se développe dans l‟état de São Paulo, en considérant l‟echaînement des factures liés à la dynamique des flux aériens des voyageurs parmi les aéroports dans l‟interface avec la capitale de cet état, qui obtient une croissance constante... (Résumé complet accès électronique ci-dessous)

APA, Harvard, Vancouver, ISO, and other styles

12

Molina, Carpio Luis. "Modélisation inverse des flux de CO2 en Amazonie." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLV040/document.

Full text

Abstract:

Une meilleure connaissance des variations saisonnières et interannuelles du cycle du carbone dans en Amazonie est essentielle afin de comprendre le rôle de cet écosystème dans le changement climatique. La modélisation atmosphérique inverse est un outil puissant pour estimer ces variations, en exploitant l'information sur la distribution spatiale et temporelle des flux de CO2 en surface contenue dans des observations de CO2 atmosphériques. Néanmoins, la confiance en les estimations des flux en Amazonie obtenues à partir des systèmes d'inversion mondiale est faible du fait du manque d'observations dans cette région.Dans ce contexte, j'ai d'abord analysé en détail les estimations de l'échange net de CO2 entre la biosphère et l'atmosphère (NEE) générées par deux inversions mondiales pour la période 2002 — 2010. Ces deux inversions ont assimilé des données provenant du réseau mondial d'observation du CO2 atmosphérique hors de l’Amérique du Sud, et une d'elles a assimilé des observations de quatre stations de surface en Amazonie, qui n'ont jamais été exploitées dans les études d'inversion précédentes. J'ai montré que dans une inversion mondiale les observations de stations loin d'Amazonie et les observations locales contrôlaient la NEE. Pourtant, les résultats ont révélé des structures à très grande échelle peu réalistes. L'analyse a confirmé le manque de stations en Amazonie pour fournir des estimations fiables, et les limites des systèmes d’inversion mondiale avec des modèles à très basse résolution.J'ai donc ensuite évalué l'apport de l'utilisation du modèle atmosphérique régional BRAMS, par rapport à celle du système mondial de prévision météorologique ECMWF, pour le forçage météorologique du modèle de transport atmosphérique CHIMERE simulant le CO2 en Amérique du Sud à haute résolution (~35 km). J'ai simulé le CO2 avec les deux modèles de transport―CHIMERE-BRAMS et CHIMERE-ECMWF. J'ai évalué ces simulations avec les profils verticaux de mesures aéroportées, en analysant les mesures individuelles et les gradients horizontaux de CO2 calculés entre paires de stations dans le sens du vent, à différentes altitudes ou intégrés sur la verticale. Les deux modèles de transport ont simulé les observations de CO2 avec une performance similaire, mais j'ai trouvé une importante incertitude sur les modèles de transport. Les mesures individuelles et les gradients horizontaux ont été surtout sensibles à la NEE, mais aussi, pendant la saison sèche, aux émissions des feux de biomasse (EFIRE). J'ai trouvé que l'assimilation des gradients horizontaux était plus approprié pour les inversions que celle des mesures individuelles, étant donné que les premiers ont été moins sensibles au signal associé aux flux hors de l'Amérique du Sud et à l'incertitude sur le modèle de transport en altitude.Finalement, j'ai développé deux systèmes d'inversion régionale pour l'Amérique du Sud tropicale avec les deux modèles de transport, et j'ai lancé des inversions avec quatre types de vecteurs d'observation: de mesures individuelles et gradients horizontaux sur cinq niveaux verticaux, à la surface, ou de gradients horizontaux intégrés sur la verticale. J'ai trouvé une forte dépendance des estimations des bilans régionaux et sub-régionaux de NEE et EFIRE au modèle de transport, ainsi qu'au vecteur d'observation. Les inversions assimilant des gradients horizontaux ont séparé mieux les signaux de NEE et EFIRE. Cependant, les grandes incertitudes sur les flux inversés ont réduit la confiance en ces estimations. Par conséquent, si mon étude n'a pas amélioré la connaissance des variations saisonnières et interannuelles de la NEE en Amazonie, elle a montré les besoins d'amélioration de la modélisation du transport dans la région et de la stratégie de modélisation inverse, du moins à travers une définition du vecteur d'observation appropriée qui prenne en compte les caractéristiques des données disponibles, et les limitations des modèles de transport actuels
A better knowledge of the seasonal and inter-annual variations of the Amazon carbon cycle is critical to understand the influence of this terrestrial ecosystem on climate change. Atmospheric inverse modeling is a powerful tool to estimate these variations by extracting the information on the spatio-temporal patterns of surface CO2 fluxes contained in observations of atmospheric CO2. However, the confidence in the Amazon flux estimates obtained from global inversion frameworks is low, given the scarcity of observations in this region.In this context, I started by analyzing in detail the Amazon net ecosystem exchange (NEE) inferred with two global inversions over the period 2002 — 2010. Both inversions assimilated data from the global observation network outside Amazonia, and one of them also assimilated data from four stations in Amazonia that had not been used in previous inversion efforts. I demonstrated that in a global inversion the observations from sites distant from Amazonia, as well as local observations, controlled the NEE inferred through the inversion. The inferred fluxes revealed large-scale structures likely not consistent with the actual NEE in Amazonia. This analysis confirmed the lack of observation sites in Amazonia to provide reliable flux estimates, and exposed the limitations of global frameworks, using low-resolution models to quantify regional fluxes. This limitations justified developing a regional approach.Then I evaluated the benefit of the regional atmospheric model BRAMS, relative to the global forecast system ECMWF, when both models provided the meteorological fields to drive the atmospheric transport model CHIMERE to simulate CO2 transport in tropical South America at high resolution (~35 km). I simulated the CO2 distribution with both transport models―CHIMERE-BRAMS and CHIMERE-ECMWF. I evaluated the model simulations with aircraft measurements in vertical profiles, analyzing the concentrations associated to the individual measurements, but also with horizontal gradients along wind direction between pairs of sites at different altitudes, or vertically integrated. Both transport models simulated the CO2 observations with similar performance, but I found a strong impact of the uncertainty in the transport models. Both individual measurements and horizontal gradients were most sensitive to NEE, but also to biomass burning CO2 emissions (EFIRE) in the dry season. I found that horizontal gradients were more suitable for inversions than individual measurements, since the former were less sensitive fluxes outside South America and further decreased the impact of the transport model uncertainty in altitude.Finally, I developed two analytical regional inversion systems for tropical South America, driven with CHIMERE-BRAMS and CHIMERE-ECMWF, and made inversions with four observation vectors: individual concentration measurements and horizontal gradients at five vertical levels, close to the surface, or horizontal gradients vertically integrated. I found a strong dependency of the inverted regional and sub-regional NEE and EFIRE emissions budgets on both the transport model and the observation vector. Inversions with gradients yielded a better separation of NEE and EFIRE signals. However, the large uncertainties in the inverted fluxes, did not yield high confidence in the estimates. Therefore, even though my study did not improve the knowledge of seasonal and year-to-year variations of the NEE in Amazonia, it demonstrated need of further efforts to improve transport modeling in the region and the inverse modeling strategy, at least through a careful definition of the observation vector that accounts for the characteristics of the available data, and the limitations of the current transport models

APA, Harvard, Vancouver, ISO, and other styles

13

Pereira, Ana Paula Camilo. "Transporte Aéreo Regional no Estado de São Paulo /." Presidente Prudente : [s.n.], 2010. http://hdl.handle.net/11449/96744.

Full text

Abstract:

Orientador: Márcio Rogério Silveira
Banca: Everaldo Santos Melazzo
Banca: Lisandra Pereira Lamoso
Resumo: O presente trabalho propõe-se a uma reflexão sobre o transporte aéreo regional no Estado de São Paulo. Considera-se, para isso, que as cidades constituem elos entre os setores de produtividade e consumo, por representarem nós de rede urbana, além de definirem a desconcentração urbano-industrial no Estado. Assim, as cidades estão inseridas em uma rede de relações sociais e econômicas e possuem importante função na organização da circulação do território e na produção do espaço urbano. O modal aéreo possibilita uma maior fluidez territorial, o que torna mais flexível a superação do espaço pelo tempo. O imperativo da sociedade atual, influenciado pelo meio técnico-científico-informacional e pelas invenções e inovações tecnológicas, exige uma mobilidade que remete a uma perspectiva intensamente renovadora dos meios de transporte. O transporte aéreo requer infraestruturas adequadas, ou seja, os fluxos demandam fixos produtivos que balizem seu movimento, assim como necessita de planejamento, regulamentação e organização do seu mercado. Nesse sentido, apresentamos nesta pesquisa uma análise geoeconômica dos fluxos aéreos no interior do Estado de São Paulo, tendo como referencial, primeiramente, uma abordagem evolucionista do setor no Brasil, que caracteriza a sua atual situação. Em seguida, relatamos como o modal tem se desenvolvido no Estado de São Paulo, considerando a processualidade dos fatores relacionados à dinâmica dos fluxos aéreos de passageiros entre os aeroportos na interface com a capital paulista, que tem obtido um constante crescimento... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Ce travail se propose à une réflexion au transport aérien régional l‟état de São Paulo. On considère, pour cela, que les villes constituent des liens entre les secteurs de productivité et consommations, puisqu‟ils réprésentent des noeuds du réseau urbain ; en plus, ils définent la déconcentration urbaine-industrielle dans l‟état. Ainsi, les cités sont inserées dans un réseau de rapports sociaux et économiques et ont d‟importante fonction dans l‟aménagement de la circulation du territoire et dans les productions de l‟espace urbain. Le modal aérien possibilite une plus grande fluidité territoriale, ce qui rend plus flexible la supération de l‟espace par le temps. L‟impératif de la société actuelle, influencé par le moyen technique-cientifique-informationnel et par les inventions et les inovations technologiques, demande une mobilité qui fait appel à une perspective intensement renovatrice des moyens de transport. Le transport aérien demande de l‟infrastructure adéquate, c‟est-à-dire, les flux demandent des fixes productifs qui conduisent leur mouvement, bien qu‟il a besoin de projetement, reglémentation e aménengement de leur marché. Dans ce sens, nous présentons dans cette recherche une analyse géoéconomique des flux aériens à l‟intérieur de l‟état de São Paulo, ayant comme référentiel, d‟abord, une approche evolutioniste du secteur au Brésil, qui caractérise la situation actuelle. À la suíte, nous racontons comme le modal se développe dans l‟état de São Paulo, en considérant l‟echaînement des factures liés à la dynamique des flux aériens des voyageurs parmi les aéroports dans l‟interface avec la capitale de cet état, qui obtient une croissance constante... (Résumé complet accès électronique ci-dessous)
Mestre

APA, Harvard, Vancouver, ISO, and other styles

14

Noumedem, Temgoua Claudia. "Highly-skilled migration : knowledge spillovers and regional performances." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0173/document.

Full text

Abstract:

Les travailleurs hautement qualifiés - scientifiques et ingénieurs en particulier - sont un atout important pour le développement d’un pays car ils sont des facteurs majeurs dans la production de connaissances. C'est ce qui justifie les efforts compétitifs déployés par plusieurs pays afin d'attirer ces travailleurs. Les pays de destination sont en général décrits comme étant les grands gagnants des migrations des travailleurs hautement qualifiés. Ce qui n'est pas le cas des pays d'origine où ces migrations sont perçues comme une perte en capital humain. Cependant, ce phénomène serait beaucoup plus complexe qu'il n'y parait. En effet, il existe d'autres facteurs inhérents à la dynamique des migrations des travailleurs hautement qualifiés qui restent soit partiellement ou totalement inexplorés dans la littérature. Ces facteurs sont liés à des éléments résultant de ces migrations et pouvant créer des retombées positives vers les pays d'origine tout en contribuant ainsi à l'innovation dans ces pays. Afin d'explorer plus en profondeur cette question, il serait nécessaire de conduire une analyse approfondie autour de la question sur la nature des liens entre migrants hautement qualifiés résidant à l'étranger d'une part et celle des liens qui lient ces migrants à leurs pays d'origine d'autre part. A travers cette analyse, nous nous proposons de contribuer au débat sur le « brain gain » en investiguant les dynamiques de diffusion des connaissances à l'intérieur du réseau des migrants hautement qualifiés dans les pays de destination, mais également vers les pays d'origine
Highly skilled workers – scientists and engineers in particular – are an important asset for a nation in so far that they enter in the production of knowledge as highly valuable human capital. That is why many countries have been competing for attracting. Receiving countries are in general pictured as the biggest winners from highly skilled migration. While the latter is perceived as a loss for sending countries. However, the situation might not be as simplistic as it seems. Indeed, we believe there are several unexplored factors underpinning the dynamics of highly skilled migration which contribute to some positive feedback to the sending countries in terms of knowledge and innovation while spurring innovation in the destination countries. And for a better understanding of these factors, one needs to look further into the nature of the ties linking highly skilled migrants abroad on one hand and to their home countries on the other hand. With our research we intend to contribute to the brain drain – brain gain trade-off debate by investigating the dynamics of knowledge diffusion within migrants’ networks in receiving countries and more importantly to sending countries

APA, Harvard, Vancouver, ISO, and other styles

15

MANCIER, CHRISTELLE. "Variabilite spatiale et temporelle de l'occurrence des foliations de tropopause : estimation du flux regional d'ozone a travers la tropopause." Paris 7, 1998. http://www.theses.fr/1998PA077098.

Full text

Abstract:

La variabilite spatiale et temporelle des foliations de tropopause est obtenue a partir de l'exploitation de deux bases de donnees de profils verticaux d'ozone, de temperature, d'humidite et de vent (radiosondages ozone/ptu/vent au centre d'archivage wodc et mesures aeroportees mozaic). La mise au point et la validation d'un algorithme de detection automatique des foliations sont presentees. Cet algorithme permet d'obtenir, a partir des deux bases de donnees, une climatologie de la frequence de l'occurrence des foliations au-dessus de l'hemisphere nord depuis trente ans. En combinant le nombre de foliations presentes simultanement en une surface et la quantite moyenne de molecules d'ozone transferees lors d'un evenement, des estimations du flux d'ozone entre la stratosphere et la troposphere, a l'echelle regionale et globale, sont realisees. L'estimation a l'chelle globale (hn) est comparee a celles obtenues par les modeles de circulation generale avec, au prealable, une reactualisation du rapport de l'ozone par la vorticite potentielle au niveau de la tropopause dynamique. Ce rapport est determine grace a une climatologie realisee au-dessus de differents sites de mesure d'ozone et a l'utilisation des analyses meteorologiques fournies par le centre europeen cepmmt.

APA, Harvard, Vancouver, ISO, and other styles

16

Nasser, Ali Djambae. "Accès aux soins et gestion des flux migratoires." Thesis, Normandie, 2018. http://www.theses.fr/2018NORMR050.

Full text

Abstract:

Mayotte département d’outre-mer français depuis 2011, fait partie de l’archipel des Comores ; elle est séparée des îles de l’État de l’Union des Comores depuis 1975. L’instauration d’un visa en 1995 et l’ordonnance n° 2002-688 du 12 juillet 2004 entréeen vigueur le 1er avril 2005 relative à l’extension de la sécurité sociale à Mayotte exclut les malades étrangers du système de santé mahorais. Ceci entraine des processus d’évacuation sanitaire par la voie d’une immigration clandestine qui provoque des naufrages et des violations des droits du patient. L’attrait de Mayotte et de la France métropolitaine pour les populations défavorisées occasionne des situations de conflits et de concurrence pour l’accès à la protection sanitaire et sociale. Les populations défavorisées de Mayotte, qui se battent pour combler leur retard par rapport à la métropole, vivent mal cette concurrence ; tandis que les populations immigrées vivant dans la clandestinité et sous la menace d’une expulsion imminente, rencontrent des difficultés pour faire valoir leur droit aux soins et au bénéfice à l’assistance du système social. Les obstacles sont nombreux et souvent considérables, dus notamment à la discrimination, à une disparité de difficultés sociales et économiques et à leurs conditions de vie généralement très difficiles. La maîtrise des flux migratoires et la lutte contre l’immigration irrégulière demeurent des priorités de la politique du gouvernement français en matière d’immigration. Laspécificité de la situation du département de Mayotte ainsi que l’importance des flux migratoires qui y sont constatés ont conduit les autorités sanitaires à gérer les flux migratoires liés aux évacuations sanitaires par la voie illégale. La France mène une politique sanitaire en continuant de soutenir l’Union des Comores dans l’amélioration de l’accessibilité et de laqualité des soins, à travers les programmes d’appui au secteur de la santé. Ces programmes auront pour finalité l’amélioration de la santé des mères et des enfants, notamment la réduction des mortalités maternelle et néonatale. La France à travers son organisme Agence française de développement (AFD) entend appuyer le ministère de la Santé dans l’élaboration et la mise en oeuvre des politiques publiques et contribuer au renforcement du cadre institutionnel et juridique du secteur. Il s’agira notamment d’appuyer l’État comorien dans la mise en place de mécanismes de régulation du service privé dans le secteur public et de réformer la pharmacie nationale. Cette recherche pointe les enjeux liés au droit de la protection sociale et au droit de la santé des étrangers sur le territoire national, aussi bien en France métropolitaine qu’à Mayotte. La diversité des droits nationaux applicables à Mayotte constitue une entrave sérieuse face aux dispositifs locaux relatifs à l'accompagnement sanitaire et social. Il est donc indispensable de chercher des solutions juridiques relatives à l’uniformisation de ce droit sanitaire et social afin d’améliorer le système de santé. Les résultats de cette recherche ont montré que les dispositifs locaux tels que le « bon rose » et le « bon AGD » ne sont pas du tout équivalents aux dispositifs nationaux (l'AME et la CMUc)
Mayotte a French overseas department since 2011, is part of the comorian archipelago from which it was separated from the State of Union of the Comoros islands since 1975. The introduction of a visa in 1995 and the order n° 2002-688 delivered on 12 july 2004 and entered into force on April 1st 2005 with regard to the extension of social security in Mayotte exclude the foreign sick from Mayotte's health system. This leads to a process of medical evacuation following an illegal immigration way that causes shipwrecks and the violation of the patient's rights. The attraction of Mayotte and Mainland France for disadvantaged populations lead to conflict situations and competition in the access to health and social protection. Mayotte's disadvantaged populations, who are struggling to catch up with the mainland, do not get along with that competition. At the same time the illegal immigrants living clandestinely and with the threat of expulsion are facing difficulties to assert their right to health care and to benefit from social system assistance. Obstacles are numerous and most of the time considerable, mainly because of discrimination, because of their judicial status, of disparity in their social and economical difficulties and because of their generaly very hard living conditions. The control of migratory flow and the fight against illegal immigrant remain the top priorities of the French government policy as far as immigration is concerned. The singularity of the situation in the department of Mayotte and the huge migratory flows that have been observed led healthcare authorities to handle migratory movements related to illegal medical evacuations. France has a healthcare policy and continues to support the Union of Comoros in the effort to improve healthcare access and quality, through support programs to health sector. These programs aim at improving the health of mothers and children, mainly in reducing maternal mortality. Through its organisation AFD, France aims at supporting health ministry in elaborating and implementing public policies and helping comorian state to put in place regulatory mechanisms of a private service within public sector and to reform the national pharmacy. This work focus on the issues related to the right to social protection and the health law for foreigners on the national territory, in mainland France and in Mayotte as well. Diversity of national laws applicable in Mayotte is a significant barrier to local devices in terms of medical and social assistance. It is necessary to seek legal solutions related to standardization of this health and social law in order to better the healthcare system. During our field research we observed that local devices such as the "pink warrant" and the "good AGD" are not at all equivalent to the national devices (AME and CMUc)

APA, Harvard, Vancouver, ISO, and other styles

17

Villatoro, Sánchez Francisco de Paula. "L'Andalousie et le Maroc : le flux migratoire et la coopération au dévelopement dans la formation de l'identité régionale andalouse (1977-2007)." Thesis, Paris 10, 2017. http://www.theses.fr/2017PA100180/document.

Full text

Abstract:

Avec ce projet de thèse, nous avons l´intention d'étudier le rôle de l'action extérieure des territoires dans la configuration de ses identités régionales. Nous allons nous concentrer sur le cas andalou au cours des dernières décennies. Ainsi, nous allons étudier l'effet de l'action extérieure de la communauté autonome d'Andalousie au cours de la période 1977-2007; accordant une attention particulière à son interaction avec le développement politique, social, économique et culturel de l'État, dans le cadre des politiques générales de l'Union européenne, et avec les territoires voisins, notamment le Maroc
With this thesis project, we intend to study the role of the external action of the territories in the configuration of its regional identities. We will focus on the Andalusian case in recent decades. Thus, we will study the effect of the external action of the Autonomous Community of Andalusia during the period 1977-2007. We will paying particular attention to its interaction with the political, social, economic and cultural development of the State, within the framework of the general policies of the European Union and with neighboring territories, in particular Morocco
Con este proyecto de tesis, pretendemos estudiar el papel de la acción externa de los territorios en la configuración de sus identidades regionales. Nos centraremos en el caso andaluz en las últimas décadas. Así, estudiaremos el efecto de la acción externa de la Comunidad Autónoma de Andalucía durante el período 1977-2007; prestando especial atención a su interacción con el desarrollo político, social, económico y cultural del Estado, en el marco de las políticas generales de la Unión Europea y con los territorios vecinos, en particular Marruecos

APA, Harvard, Vancouver, ISO, and other styles

18

Brixel, Bernard. "Quantification of the regional groundwater flux to a northern peatland complex, Schefferville, Québec, Canada: results from a water budget and numerical simulations." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=97107.

Full text

Abstract:

Peatlands are significant soil carbon and freshwater reservoirs at the global scale, and thus play a key role in the global carbon and water cycles. Peatland inception and development are intrinsically related to optimal environmental conditions, including an adequate hydro-morphological setting that promotes the occurrence of waterlogged soils and low topographic gradients. This thesis investigates the hydrology of 0.2 km2 northern peatland complex, located in the region of Schefferville, Québec, Canada, in which a significant area has developed over a relatively steep topographic gradient. The objective of this thesis is to quantify and characterize the spatiotemporal flux of regional groundwater to the peatland local flow system in an attempt to evaluate the relative importance of this flux compared with other water inputs. A three-dimensional groundwater flow model, the finite-difference U.S. Geological Survey MODFLOW code, is used to simulate the peatland and characterize the groundwater flow system. The model is parameterized with data measured from June 17th to September 4th, 2009, including continuous meteorological measurements from an automatic weather station, 14 observation wells, and two 90° V-notch weirs gauging stream discharge. This study establishes that, over the measuring period, the regional groundwater influx accounted for 27% ± 0.4% of the total water inputs, the remainder 73% ± 0.4% consisting of precipitation (54% ± 0.4%), surface water inflow (14% ± 0.4%), and change in storage (5% ± 0.4%). Consequently, it is the main conclusion of this work that regional groundwater inflows were, volumetrically, the second most important source of water to the peatland local flow system.
Les tourbières représentent d'importants réservoirs naturels riches en carbone et en eau douce à l'échelle globale. Ils jouent par conséquent un rôle majeur à la fois dans le cycle du carbone et le cycle hydrologique. L'origine et le développement des tourbières sont liés à l'existence de circonstances environnementales optimales. Il s'agit essentiellement d'un contexte hydro-morphologique adéquat favorisant l'occurrence de sols saturés en eau sur des terrains relativement plats. Ce document présente les résultats d'une étude scientifique conduite dans un complexe tourbier nordique, situé dans la région de Schefferville, Québec, Canada. Ce terrain représente un cas particulier peu observé dans la nature : une large partie de l'accumulation de matière organique a eu lieu sur un gradient topographique prononcé. L'objectif de cette étude est de quantifier et caractériser le flux spatiotemporel du système de circulation de l'eau souterraine régional à la nappe d'aquifère du système tourbier local. Un modèle numérique de circulation de l'eau souterraine est utilisé afin de simuler le système tourbier et caractériser son régime hydraulique. Basé sur le code informatique du modèle MODFLOW, développé par le Service de Géologie des Etats Unis (McDonald and Harbaugh 1988), le modèle tridimensionnel est utilisé afin de simuler la circulation des eaux sou terraine. Le modèle incorpore une série de données météorologiques et hydrométriques en tant que paramètres d'entrée. Mesurées entre le 17 juin et le 4 septembre 2009, ces données proviennent d'une station météo installée pour les besoins de l'étude sur le terrain même, ainsi que 14 puits d'observations et 2 barrages pour mesure le débit. Cette étude établit que, sur l'ensemble de la période d'étude, le flux de l eau souterraine du système régional a représenté 27% des entrées en eau. Les 73% restant se divisent entre 54% pour la précipitation, 14% pour l influx de surface et 5% pour le changement de stockage hydraulique. En conséquence, la conclusion majeure de cette étude est que le flux régional d'eau souterraine est, d'un point de vue volumétrique, le deuxième flux le plus important dans le system tourbier nordique.

APA, Harvard, Vancouver, ISO, and other styles

19

McKain, Kathryn. "Carbon accumulation at the Harvard Forest : a comparison of methods for measuring tree biomass for regional extrapolation of the eddy-flux tower footprint /." Connect to online version, 2005. http://ada.mtholyoke.edu/setr/websrc/pdfs/www/2005/100.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

20

Fernández, León Alejandro. "SPECT cerebral de neuroactivación con torre de Hanoi en el estudio del trastorno obsesivo compulsivo." Doctoral thesis, Universitat de Barcelona, 2003. http://hdl.handle.net/10803/2164.

Full text

Abstract:

El objetivo de esta tesis doctoral fue la evaluación de cambios en el flujo sanguíneo cerebral regional (FSCR) en pacientes afectados de trastorno obsesivo-compulsivo (TOC) y controles sanos durante la ejecución de la tarea cognitiva "Torre de Hanoi" (TH).
Para ello se dividió el trabajo en dos partes: 1) optimización de la técnica gammagráfica teniendo en cuenta todos los aspectos involucrados en la misma (control de calidad del aparataje, radiofármaco, adquisición de las imágenes, procesado de las mismas y optimización de la cuantificación; y 2) estudio clínico y de evaluación del FSCR de una población de pacientes y otra comparable de voluntarios sanos.
MATERIAL Y MÉTODO: mediante búsqueda bibliográfica y realización de pequeños experimentos con maniquíes se decidieron todos los parámetros que resultasen en una tomogammagrafía de la máxima calidad.
A nivel clínico se comparó los resultados de la ejecución del test de la TH en 30 pacientes con TOC y una población comparable de voluntarios sanos. Se realizaron medidas psicológicas de la inteligencia y ansiedad a todos los sujetos del estudio. En el grupo de pacientes se evaluó además la severidad de los síntomas y la posible presencia de depresión. El FSCR se estimó mediante SPECT cerebral con hexamethylpropylamina-oxima (HMPAO). Los valores regionales se determinaron usando la actividad cortical como referencia.
RESULTADOS: tras el proceso de optimización (que duró un año) se consiguió obtener imágenes de SPECT cerebral lo suficientemente óptimas como para poder evaluar de manera válida el FSCR y de esta manera pasar a evaluar posibles diferencias en el mismo.
En la evaluación clínica los pacientes y controles se diferenciaron significativamente en cuanto a la presencia de ansiedad. La ejecución de la prueba de la TH fue peor en los pacientes con TOC que en los controles. La prueba de la t de Student para medidas apareadas puso de manifiesto diferencias significativas (p= 0,039) entre pacientes y controles en cuanto a la activación del núcleo caudado izquierdo. Los controles activaron dicho núcleo durante la ejecución de la TH y los pacientes no. No aparecieron diferencias en otras regiones cerebrales.
CONCLUSIÓN: estos resultados sugieren una modificación en los sistemas de activación de los ganglios basales en pacientes con TOC comparados con controles.

APA, Harvard, Vancouver, ISO, and other styles

21

Zhao, Yanhai. "L'insertion de la Chine dans la mondialisation, les flux d'investissements directs étrangers et la disparité économique régionale en Chine." Phd thesis, Université de la Sorbonne nouvelle - Paris III, 2009. http://tel.archives-ouvertes.fr/tel-00771885.

Full text

Abstract:

Depuis 1979, la Chine a entrepris les politiques des Réformes et de l'Ouverture. Cette période marque un tournant de la Chine. La libéralisation du marché, l'industrialisation et l'internationalisation, qui sont réalisées de manière systématique et graduelle, ont permis d'intégrer la Chine dans l'économie mondiale et la mondialisation. En étudiant le processus de la mondialisation et du développement régional en Chine, nous pouvons constater une évolution multipolaire : une transition de l'économie traditionnelle, planifiée et fermée vers une économie moderne et ouverte du marché, une transformation d'une société agricole vers une société industrielle et de services et un changement conceptuel du centrisme chinois et de tradition vers la mondialisation et la modernité. Cette évolution est le résultat des forces irrésistibles de la mondialisation et des expériences de la Chine quant à son refus, sa résistance, son acceptation forcée, et ses essais en matière d'apprentissage vers la mondialisation. Cependant, la croissance n'est pas partagée de manière équilibrée entre les régions de la Chine. En raison des différences dans l'environnement naturel, dans les ressources, dans les structures industrielles, dans le développement social et compte tenu des éléments historiques et politiques, le développement des régions retardées est une question qui relève non seulement de la stabilité économique et politique de la Chine, mais aussi d'une source de durabilité de la croissance chinoise. Les IDE sont un des facteurs contribuant à la croissance économique en Chine, mais ils ne sont pas les seuls facteurs fautifs à l'écart de la disparité en Chine.

APA, Harvard, Vancouver, ISO, and other styles

22

Sridhar, Harshitha. "The Impact of Boundary Condition on Groundwater Flow : Topography v/s Recharge Controlled." Thesis, KTH, Hållbar utveckling, miljövetenskap och teknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-286148.

Full text

Abstract:

Groundwater interactions at a regional scale are of great importance to characterize subsurface flow processes. Extensive researches have been conducted previously to determine the main factors controlling the regional implications on groundwater flux circulation. Groundwater circulation occurs due to variation in the groundwater table (hydraulic gradient) across the spatial scale. Previous research highlighted the correlation between groundwater table with both topography variation and the recharge from precipitation. This study aims to highlight the impact of these boundary conditions. Five catchments located across different regions of Sweden with different topographical, hydrological, and meteorological properties considered for this study: Bodalsån, Forsmarksån, Tullstorpsån, Sävaån, and Krycklan. Relevant data were collected and numerical models were set up in steady- state conditions for each of these catchments, using 3D Multiphysics COMSOL. Models were set up for both of the boundary conditions, using 10 m grid resolution.Groundwater flux profiles along the depth of the catchments were obtained as a result, in which significant differences were observed. This was associated predominantly with the difference in the nature of the topography, the slope and soil permeability in these regions. The data thus collected and the models so established have increased the understanding in these regions from a research perspective.
En ökad förståelse för hur grundvatten interagerar med ytvatten är av stor betydelse för att karakterisera underjordiska flödesprocesser. Omfattande undersökningar har tidigare genomförts för att bestämma de viktigaste faktorerna som styr de regionala konsekvenserna för cirkulationen av grundvattenflöde. Grundvattencirkulation uppstår på grund av variationer i grundvattentabellen (hydraulisk gradient) över den rumsliga skalan. Tidigare forskning belyste korrelationen mellan grundvattentabellen med både topografivariation och laddning från nederbörd. Denna studie syftar till att belysa effekterna av dessa gränsförhållanden. Fem avrinningsområden placerade över olika regioner i Sverige med olika topografiska, hydrologiska och meteorologiska egenskaper som beaktas för denna studie: Bodalsån, Forsmarksån, Tullstorpsån, Sävaån och Krycklan. Relevanta data samlades in och numeriska modeller sattes upp under steady-state-förhållanden för vart och ett av dessa avrinningsområden med användning av 3D Multiphysics COMSOL. Modeller konfigurerades för båda gränsförhållandena med 10 m nätupplösning. Grundvattenflödesprofiler längs avrinningsdjupet erhölls som resultat, där signifikanta skillnader observerades. Detta var främst förknippat med skillnaden i topografins natur och lutningen i dessa regioner. De data som samlats in och de så etablerade modellerna har ökat skapat en värdefull grund för vidare hydrologisk forskning i dessa regioner.

APA, Harvard, Vancouver, ISO, and other styles

23

Mainsant, Gildas. "Réponse des masses d'eau intermédiaires et modales de l'océan Austral au mode annulaire austral : les processus en jeu et rôle de la glace de mer." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENU060/document.

Full text

Abstract:

Les tendances climatiques récentes montrent un réchauffement et un adoucissement des couches de surface dans la région du courant circumpolaire antarctique (ACC).Sur la même période, les vents d'ouest pilotant la circulation de l'océan Austral ont significativement augmentés. Cette augmentation est en partie liée à l'intensification du mode annulaire austral (SAM), principal mode de variabilité atmosphérique au sud de 20°S. Dans cette thèse, on s'intéresse à comprendre les effets de la tendance positive du SAM sur les propriétés des masses d'eau formées dans la région de l'ACC.A cette fin, on met en place une stratégie de simulations régionales couplées océan-glace de mer et forcées par une série de scénarios atmosphériques perturbés. Les scénarios atmosphériques sont construits à partir de réanalyses atmosphériques afin de décrire les différentes composantes (dynamiques et thermodynamiques) des changements liés au SAM.En réponse à l'intensification du SAM, les simulations montrent une forte salinisation de la couche de mélange océanique ainsi que des eaux modales (SAMW) et intermédiaires (AAIW).L'essentiel de ces changements peut être attribué aux composantes dynamiques du SAM. Dans les régions saisonnières englacées, les composantes thermodynamiques du SAM peuvent jouer un rôle important (en particulier en mer d'Amundsen et en mer de Weddell). Les simulations montrent également le rôle clef joué par la glacede mer dans la médiation des changements atmosphériques vers l'océan intérieur. Ces résultats de simulations suggèrent que le SAM ne serait pas le seul pilote des tendances climatiques récentes dans l'océan Austral
Recent climate trends show a warming and freshening of the surface layers in the region of the Antarctic Circumpolar Current (ACC). Over the same period, the westerlies driving the circulation of the Southern Ocean have significantly increased. This increase is partly due to the intensification of the Southern Annular Mode (SAM), the main mode of atmospheric variability south of 20°S. In this thesis, we are interested in understanding the effects of the positive trend of the SAM onto the properties of water masses formed in the region of the ACC. To do so, we implement a strategy of regional coupled ocean-sea ice simulations forced by a series of atmospheric disturbance scenarios.These scenarios are constructed from atmospheric reanalyses in order to describe the various components (dynamic and thermodynamic) of the changes related to the SAM. In response to the increase of the SAM, the simulations show a significant salinification of the ocean mixed layer and of the mode water (SAMW) and intermediate water (AAIW).Most of these changes can be attributed to the dynamic components of the SAM. In Seasonal Ice Zone, the thermodynamic components of the SAM can play an important part (especially in Amundsen Sea and Weddell Sea). The simulations also show the key role played by sea ice in mediating atmospheric changes toward the interior ocean.These simulation results suggest that SAM is not the only driver of recent climate trends in the Southern Ocean

APA, Harvard, Vancouver, ISO, and other styles

24

Svirejeva-Hopkins, Anastasia. "Urbanised territories as a specific component of the global carbon cycle." Phd thesis, [S.l. : s.n.], 2004. http://pub.ub.uni-potsdam.de/2004/0051/hopkins.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Miyashiro, Mauro Massanori. "Avalia??o da efici?ncia energ?tica de l?mpadas LED." Pontif?cia Universidade Cat?lica de Campinas, 2017. http://tede.bibliotecadigital.puc-campinas.edu.br:8080/jspui/handle/tede/916.

Full text

Abstract:

Submitted by SBI Biblioteca Digital (sbi.bibliotecadigital@puc-campinas.edu.br) on 2017-03-10T19:12:54Z No. of bitstreams: 1 MAURO MASSANORI MIYASHIRO.pdf: 2380997 bytes, checksum: fc2d550825d50d0a996842532845e496 (MD5)
Made available in DSpace on 2017-03-10T19:12:54Z (GMT). No. of bitstreams: 1 MAURO MASSANORI MIYASHIRO.pdf: 2380997 bytes, checksum: fc2d550825d50d0a996842532845e496 (MD5) Previous issue date: 2017-02-09
Light Emmiting Diode ? LED. Efici?ncia energ?tica. Portaria n? 144/2015. INMETRO. Fator de pot?ncia. Fluxo luminoso. Efici?ncia energ?tica. The objective of this study was to evaluate the energy efficiency of LED light bulbs (Light Emitting Diode) commercialized in the Brazilian market in the period of 2015/2016 and the development of a low cost test system to measure the mains voltage, current, consumption and power factor of LED lamp. For the evaluation of the LED lamps, the equipment available in the laboratories of the Eldorado Research Institute was used, and as a reference, the requirements established by Ordinance No. 144/2015 of the Instituto Nacional de Metrologia, Qualidade e Tecnologia - INMETRO, published on March 13, 2015. This Ordinance made it mandatory for manufacturers and importers to certify LED bulbs as of February 26, 2016. In order to carry out this work, a set of LED lamps from different manufacturers was acquired in the retail market to be subjected to functional tests of consumption of energy (watts), power factor (PF), luminous flux (lumens) and luminous efficiency (lumens/watt). The data obtained were compared with the nominal values declared by the manufacturers, as specified in the INMETRO ordinance. The results show that 11% of the samples failed in the energy consumption test and 83% failed in the power factor test. The developed test system was validated comparing its measurements with the results obtained in the tests carried out in INMETRO certified laboratory. Through this work it was possible to have an overview of the energy efficiency of LED bulbs currently commercialized in the country.
O presente trabalho teve como objetivo avaliar a efici?ncia energ?tica de l?mpadas com tecnologia LED (Light Emitting Diode) comercializadas no mercado brasileiro no per?odo de 2015/2016 e o desenvolvimento de um sistema de teste de baixo custo para medir a tens?o da rede el?trica, a corrente, o consumo e o fator de pot?ncia de l?mpada LED. Para a avalia??o das l?mpadas LED foram utilizados os equipamentos dispon?veis nos laborat?rios do Instituto de Pesquisas Eldorado e como refer?ncia os requisitos estabelecidos pela Portaria n? 144/2015 do Instituto Nacional de Metrologia, Qualidade e Tecnologia - INMETRO, publicada em 13 de mar?o de 2015. Esta Portaria tornou obrigat?ria para fabricantes e importadores a certifica??o das l?mpadas LED a partir de 26 de fevereiro de 2016. Para a realiza??o deste trabalho foi adquirido no mercado de varejo um conjunto de l?mpadas LED de diferentes fabricantes para serem submetidos a testes funcionais de consumo de energia (watts), fator de pot?ncia (FP), fluxo luminoso (lumens) e efici?ncia luminosa (lumens/watt). Os dados obtidos foram comparados com os valores nominais declarados pelos fabricantes conforme especificado na portaria do INMETRO. Os resultados demonstram que 11% das amostras falharam no teste de consumo de energia e 83% falharam no teste de fator de pot?ncia. O sistema de teste desenvolvido foi validado comparando suas medi??es com os resultados obtidos nos testes realizados em laborat?rio certificado pelo INMETRO. Atrav?s deste trabalho foi poss?vel ter um panorama amostral da efici?ncia energ?tica das l?mpadas LED comercializadas atualmente no pa?s.

APA, Harvard, Vancouver, ISO, and other styles

26

MacTaggart, David. "Theoretical magnetic flux emergence." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/1692.

Full text

Abstract:

Magnetic flux emergence is the subject of how magnetic fields from the solar interior can rise and expand into the atmosphere to produce active regions. It is the link that joins dynamics in the convection zone with dynamics in the atmosphere. In this thesis, we study many aspects of magnetic flux emergence through mathematical modelling and computer simulations. Our primary aim is to understand the key physical processes that lie behind emergence. The first chapter introduces flux emergence and the theoretical framework, magnetohydrodynamics (MHD), that describes it. In the second chapter, we discuss the numerical techniques used to solve the highly non-linear problems that arise from flux emergence. The third chapter summarizes the current literature. In the fourth chapter, we consider how changing the geometry and parameter values of the initial magnetic field can affect the dynamic evolution of the emerging magnetic field. For an initial toroidal magnetic field, it is found that its axis can emerge to the corona if the tube’s initial field strength is large enough. The fifth chapter describes how flux emergence models can produce large-scale solar eruptions. A 2.5D model of the breakout model, using only dynamic flux emergence, fails to produce any large scale eruptions. A 3D model of toroidal emergence with an overlying magnetic field does, however, produce multiple large-scale eruptions and the form of these is related to the breakout model. The sixth chapter is concerned with signatures of flux emergence and how to identify emerging twisted magnetic structures correctly. Here, a flux emergence model produces signatures found in observations. The signatures from the model, however, have different underlying physical mechanisms to the original interpretations of the observations. The thesis concludes with some final thoughts on current trends in theoretical magnetic flux emergence and possible future directions.

APA, Harvard, Vancouver, ISO, and other styles

27

Bubier, Jill L. "Methane flux and plant distribution in northern peatlands." Thesis, McGill University, 1993. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41554.

Full text

Abstract:

Methane (CH$ sb4$) fluxes were measured in a range of peatland sites by a static chamber method in two regions of northern Canada, the Clay Belt of boreal Ontario and the Labrador Trough of subarctic Quebec. In both regions, seasonal mean water table position was the best predictor of mean CH$ sb4$ flux when microtopography was included in the analysis (r$ sp2$ = 0.73; p $<$ 0.01). The regression coefficients (slopes) were similar in both regions, suggesting a similar functional relationship between water table position and CH$ sb4$ flux; but the constants (intercepts) were different, implying a regional difference in climate or other biogeochemical factors. Broad-scale wetland classifications that do not account for microtopography and regional differences are inadequate for predicting CH$ sb4$ flux.
Vegetation and a suite of environmental variables in both regions were analyzed with multivariate statistics. Canonical correspondence analysis (CCA) showed that hydrology (water table position) explains most of the variability in bryophyte distribution, with chemistry (pore-water pH, Ca, Mg) as the second most important factor. The relative importance of the variables is reversed for vascular species in the Clay Belt; variables correlating with bryophyte and vascular species distribution are more similar in the Labrador Trough. Hydrology and chemistry are independent variables in both regions. CH$ sb4$ flux correlated strongly with hydrology in both regions, but not with chemistry.
Because of the strong correlation between bryophytes and CH$ sb4$ flux in the CCA analyses, a predictive model was developed using weighted averaging (WA) calibration. Optimum CH$ sb4$ flux values are highest for carpet/pool species and lowest for hummock species. No overlap in WA tolerances occurs between hummock and pool species, suggesting species at either end of the moisture gradient are the best predictors of CH$ sb4$ flux. Although the model works best within and not among regions, it has potential application in remote sensing of bryophytes for regional CH$ sb4$ budgets, paleoenvironmental reconstructions of CH$ sb4$ flux, and biological monitoring of future changes in CH$ sb4$ flux from climate-induced changes in peatland hydrology.

APA, Harvard, Vancouver, ISO, and other styles

28

Silva, Carlos Henrique da. "Efeito da pregabalina no fluxo sanguíneo cerebral regional em pacientes portadores de esquizofrenia." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/17/17148/tde-06012016-165605/.

Full text

Abstract:

A esquizofrenia continua sendo um dos transtornos mais desafiadores para a clínica psiquiátrica, apesar dos avanços dos estudos que tentam elucidar sua fisiopatologia e buscam novas opções de tratamento, isto impulsionado pela eficácia limitada dos atuais antipsicóticos utilizados no tratamento de tal transtorno. A pregabalina é uma nova droga antiepiléptica, também usada para controle de dores neuropáticas pós-herpéticas, dores neuropáticas diabéticas, fibromialgia, e recentemente aprovada para o tratamento de transtornos ansiosos. Tem como provável mecanismo de ação um incremento na função gabaérgica, apesar de não interagir com receptores gabaérgicos, pois atua através de sua ligação com a subunidade 2 dos canais de cálcio neuronais, diminuindo assim a liberação de neurotransmissores. Frente às evidências da existência de uma eficácia provável da pregabalina em sintomas psicóticos, ao menos como adjuvante, e do crescente interesse terapêutico no uso da mesma em diferentes transtornos, justifica-se um estudo que envolva pacientes esquizofrênicos utilizando tal medicação. Nas duas últimas décadas, o estudo dos mecanismos neurobiológicos subjacentes aos transtornos psiquiátricos, bem como a investigação dos possíveis mecanismos e regiões cerebrais influenciadas por substâncias psicofarmacológicas, recebeu importante contribuição das técnicas de neuroimagem funcional. Apesar disto, até o momento não existe nenhum estudo que procurou avaliar os mecanismos centrais relacionados às propriedades ansiogênicas e/ou ansiolíticas, bem como anticonvulsivantes e analgésicas da pregabalina em humanos. Assim, o presente estudo tem como objetivo investigar os efeitos da pregabalina no fluxo sangüíneo cerebral em 20 portadores de esquizofrenia, utilizando tomografia por emissão de fóton único - SPECT, em um estudo cruzado, duplo-cego, controlado por placebo. A avaliação de alterações psicopatológicas dos voluntários durante a ação da pregabalina foi feita com a Escala Breve de Avaliação Psiquiátrica- Brief Psychiatric Rating Scale-BPRS, os estados subjetivos secundários à ação da pregabalina foram avaliados com a Visual Analogic Mood Scale VAMS. O resultado das imagens mostra alterações significativas de perfusão em estruturas que compõem via glutamatérgica (pré-frontal-temporal-tálamo) com principal diminuição de ativação no córtex frontal superior. Houve aumento de ativação em estruturas relacionadas à motricidade (giro pré-central e áreas do cerebelo tuber, uncus, culmen). Os dados apóiam a hipótese de que a pregabalina age modulando neurotransmissores nestas regiões e sistemas. A pregabalina apresenta potencial no tratamento de sintomas ansiosos de pacientes psicóticos.
Schizophrenia remains as one of the most challenging disorders to psychiatry in spite of advances achieved by studies attempting to elucidate its physiopathology and find for new options of treatment, considering the limited efficacy of current antipsychotic medication used in the treatment of this disorder. Pregabalin is a novel antiepileptic drug which is also used in the treatment and control of post-herpetic neuropathic pain, diabetic neuropathic pain and fibromyalgia, and it has recently been approved for the treatment of anxiety disorders. Its possibly acts through the increase in the gabaergic function, although it doesn\'t interact directly with gabaergic receptors, it acts on 2 subunits of neuronal calcium channel, thus decreasing the release of neurotransmitters. The present study was considered relevant due to the evidence of a possible efficacy of pregabalin on psychotic symptoms, at least as add-on treatment, and the increased therapeutic interest concerning the use of the drug in different disorders. In the past two decades the neurobiological mechanisms related to psychiatric disorders as well as the investigation of possible mechanisms and brain regions influenced by pharmacological substances received important technical contributions from functional neuroimage techniques. However, currently, there are no studies evaluating the mechanisms related to the anxiogenic and/or anxiolytic, and anticonvulsant and analgesic properties of pregabalin in humans. Therefore, the present study aimed to investigate the effects of pregabalin in the cerebral brain flow of 20 patients with schizophrenia, using single photon emission tomography SPECT, in a crossed double-blind placebo controlled study. Psychopathological alterations during the use of pregabalin was performed with the Brief Psychiatric Rating Scale-BPRS, subjective state was evaluated with Visual Analogic Mood Scale VAMS. Image analysis shows significant hipoperfusion in structures of the glutamatergic pathway (pré-frontal-temporal-thalamus), with main hipoactivation in the superior frontal cortex. There has been an increase of activation in motor areas (the precentral gyrus and cerebellar structures tuber, uncus, culmen). Data analysis supports the hypothesis that pregabalin acts by modulating neurotransmitters in these areas. Pregabalin shows potential for the treatment of anxiety in psychotic patients.

APA, Harvard, Vancouver, ISO, and other styles

29

Chan, Ka Long. "Coordenação fiscal regional na área da Grande Baía:uma perspetiva de fluxo de talentos." Master's thesis, Instituto Superior de Ciências Sociais e Políticas, 2019. http://hdl.handle.net/10400.5/19280.

Full text

Abstract:

Dissertação de Mestrado em Administração Pública
Estudamos o papel da coordenação fiscal regional na promoção do fluxo de trabalhadores talentosos na Área da Grande Baía de Guangdong, Hong Kong e Macau (GBA). Num contexto de crescentes atividades transfronteiriças e maior integração regional, é crucial que os governos descubram até que ponto diferentes sistemas fiscais na Grande Baía impedem a circulação de talentos regionais. Primeiro, comparamos as leis fiscais relevantes para clarificar onde estão as diferenças. De seguida, determinamos o impacto do imposto de duas formas. Em primeiro lugar, para determinar o nível de rendimento líquido de impostos, simulamos a taxa efetiva de imposto usando um perfil do rendimento para trabalhadores talentosos. Depois, reportamos as conclusões de uma entrevista em grupo com profissionais, especialistas e professores, a fim de compreender melhor as nuances das diferenças em termos de tributação regional. Concluímos que as diferenças na tributação dos rendimentos do trabalho causam impactos negativos tanto na mobilidade do fator trabalho como na vontade de trabalhadores talentosos irem trabalhar para a parte continental da GBA. Certas medidas fiscais, com o objetivo de promover a circulação de talentos, provavelmente levarão a efeitos indesejados. No contexto de uma melhor coordenação fiscal regional, salientamos uma série de passos futuros para mitigar os impactos negativos dos impostos no fluxo regional de talento.
We study the role of regional tax coordination in promoting the flow of talented workers in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA). In a context of increasing crossboundary activities and greater regional integration, it is crucial for governments to determine to what extent different tax systems in the GBA hinder regional talent flow. We first compare the relevant tax laws to clarify where the differences lie. Then we determine the impact of taxes in two ways. First, to determine the after-taxes income level, we simulate the effective tax burden using an income profile of talented workers. Then, we report on a group interview with professionals and experts aimed at better understanding the nuances of differential regional taxation. We conclude that the differences in labour income taxation are deleterious both to labour mobility and to the personal willingness of talented workers to work on the mainland side of the GBA. Certain tax measures, with the purpose of promoting regional talent flow, are likely to lead to certain unintended effects, such as a social justice problem. In the context of better regional tax coordination, we highlight a number of future steps to mitigate the negative impacts of tax on regional talent flow.
N/A

APA, Harvard, Vancouver, ISO, and other styles

30

Letts, Matthew Guy. "Modelling peatland soil climate and methane flux using the Canadian Land Surface Scheme." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=21590.

Full text

Abstract:

A soil climate parameterization is designed for peatland environments in the Canadian Land Surface Scheme (CLASS). Three wetland soil classes account for the variation in the hydraulic characteristics of organic soils. Saturated hydraulic conductivity varies from a median of 1.0 x 10-7 m/s in deeply humidified sapric peat to 2.8 x 10-4 m/s in relatively undecomposed fibric peat. Average pore volume fraction ranges from 0.83 to 0.93. Parameters are derived for the soil moisture characteristic curves of fibric, hemic and sapric peat, using the Campbell (1974) equation employed in CLASS, and the van Genuchten (1980) formulation. Validation of modelled water table depth and peat temperature is performed for a fen in northern Quebec and a bog in north-central Minnesota. The new parameterization results in more realistic simulation than the previous version of CLASS, which was constrained to using mineral soil properties to approximate those of organic soils.
Two approaches are used to model methane emissions from northern peatlands using the new soil climate parameterization in CLASS. In the first module, the multiple regression equation of Dise et al. (1993) is used to simulate daily methane emissions from water table depth and peat temperature. In the process-based module, methane flux is divided into its component parts: plant transport, diffusion and ebullition. Each of these transport mechanisms is determined by methane concentrations, which are calculated from a series of processes related to peat temperature, water table level and rooting depth. The daily methane emissions predicted by the two models are similar and correlate reasonably with observations from a bog in north-central Minnesota.

APA, Harvard, Vancouver, ISO, and other styles

31

Lima, Monica Colares Oliveira. "Estudo comparativo do fluxo sanguineo cerebral regional (SPECT) entre pacientes esquizofrenicos e controle normais." [s.n.], 1998. http://repositorio.unicamp.br/jspui/handle/REPOSIP/311446.

Full text

Abstract:

Orientador: Neury Botega
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
Made available in DSpace on 2018-07-23T21:43:21Z (GMT). No. of bitstreams: 1 Lima_MonicaColaresOliveira_D.pdf: 14696535 bytes, checksum: 4829e86bde15c3ca1c7284a7559266e6 (MD5) Previous issue date: 1998
Resumo: A esquizofrenia é um distúrbio psicótico grave, que acomete preferencialmente adultos jovens, causando danos que se prolongam durante toda a vida do indivíduo. É de etiologia multifatorial com aspectos genéticos, ambientais e neurobiológicos implicados na sua gênese. As técnicas de neuroimagem têm demonstrado alterações do metabolismo e do fluxo Sangüíneo Cerebral- regional (FSCr). Neste estudo, objetivamos verificar as alterações do FSCr em esquizofrênicos, quando comparados a controles nonnais, as regiões afetadas e as correlações com a sintomatologia (positiva ou negativa). Método: estudo do tipo casocontrole, onde se realizou SPECT cerebral com 99mtc - HMPAO em condições de repouso em 30 esquizofrênicos e 17 controles normais pareados por sexo e idade; fez-se o diagnóstico de acordo com os critérios do DSMIII-R para esquizofrenia; aplicou-se a PANSS para avaliação e mensuração dos sintomas positivos e negativos. Os pacientes utilizaram neurolépticos típicos (n = 13) e risperidona (n = 14). O SPECT foi interpretado qualitativamente pela equipe de médicos nucleares da UNICAMP; quantitativamente foi err,tpregado o método ROIlcerebelo. Realizou-se análise multivariada (ANOVA) no planejamento com medidas repetidas e com modelo fatorial cruzado, considerando a classificação grupal e o sexo, e análise discriminante. Resultados: nos esquizofrênicos em relação aos controles, observou-se redução do FSCr no lobo frontal, nos glânglios da base e na área visual, bilateralmente; os pacientes com síndrome negativa (tipo 11 de Crow) apresentaram redução do FSCr no lobo frontal bilateralmente (mais significativamente no hemisfério esquerdo), nos lobos temporal e parietal esquerdos; pacientes com síndrome positiva (tipo I de Crow) e mista apresentaram redução e aumento do FSCr em diferentes áreas cerebrais; estas alterações foram detectadas apenas qualitativamente. Pacientes dos subtipos clínicos desorganizado e catatônico apresentaram redução do FSCr frontal bilateralmente e parietal esquerdo. Pacientes utilizando risperidona apresentaram maior FSCr que aqueles utilizando neurolépticos típicos, no lobo temporal esquerdo no giro do cíngulo e no lobo parietal direito. Conclusões: pacientes esquizofrênicos apresentam hipoperfusão no lobo frontal e gânglios da base, sugerindo uma alteração fisiológica cortical e subcortical. Pacientes com sintomatologia negativa apresentam hipoperfusão frontal, temporal e parietal esquerdos. A disfunção nestas áreas pode justificar a síndrome negativa que está especialmente relacionada às funções do lobo frontal, como o afastamento social e o embotamento afetivo e do lobo temporal, como a alogia. Pacientes com sintomas positivos e mistos apresentam um padrão de perfusão cerebral variável com áreas de redução e aumento do FSCr, sugerindo uma alteração fisiológica em diversos sistemas e regiões cerebrais, que podem estar hiperfuncionantes (relacionando-se aos sintomas positivos) e hipofuncionantes (relacionando-se aos sintomas negativos). Os neurolépticos podem atuar em regiões cerebrais diferenciadas, o que pode justificar a diversidade dos efeitos terapêuticos e colaterais
Abstract: The schizophrenia is a serious psychotic disturbance. It attacks preferably the young adults, causing injuries that extends to the individual's all life. It is of multifactorial etiology with genetics, environrnental and neurobiological aspects implied in its genesis. The neuroimaging studies have showed changes in the metabolism and in the regional cerebral blood flow (rCBF). The aim ofthis study is to fmd out the alterations ofrCBF in schizophrenics as compared to normal control, the affected regions and the correlations with the symptoms (positive and negative). Method: study of the type case-control, where it was done SPECT cerebral with 99mtc-HMPAO as the tracer, in resting conditions in 30 schizophrenics and a group of 17 normal control subjects. The diagnosis was done according to the criteria of DSMIII-R to schizophrenia. It was applied the PANSS for evaluation and mensuration ofthe positive and negative symptoms. The patients used typical neuroleptics (n = 13) and risperidone (n = 14). The SPECTwas interpreted qualitativelybythe team ofnuclear doctors ofUNICAMP. Itwas used the method ROI/cerebellum quantitatively. The multivaried analysis. (ANOVA) was prepared in the planning with repeated measures with crossed factorial model, considering the group classification and the sex, and the discriminating analysis. Results: In the schizophrenics, in relation to controls, it was observed the reduction ofrCBF in the frontallobe, in the basal ganglions and in the visual area bilateraly. In the patients with negative syndrome (typ.e II of CROW), it was presented reduction of rCBF in the frontallobe bilareraly (more significantly in the left hemysphere), in the left temporal and parietallobes; patients with positive syndrome (type I ofGROW) and mixed presented reduction and increase ofrCBF in different cerebral areas; this increase was detected only qualitatively. Patients of clynical subtype disorganized and catatonic presented reduction of rCBF frontal bilaterally and left parietal. Patients using risperidone displayed bigger rCBF than those who used typical neuroleptics, in the left temporallobe in the cingulate gyrus and in the right parietallobe. Conclusions: The schizophrenics patients presented hipoperfusioll in the frontallobe and ganglions ofthe base, suggestingphysiological control alld subcortical alteration. The ones with negative symptoms showed frontal, temporal and parietalleft hipoperfusion. The disfunction of these areas can justify the negative syndrome that is specially related to the functions offrontallobe, as the social removal and the temporallobe as the alogia. Patients with positive and mixed symptoms revealed a pattern of variable cerebral perfusion with areas of reduction and increase of rCBF. showing a physiological alteration in several syst~ms and cerebral regions that may be hiperfunctioning (concerning the positive symptoms) and hipofunctioning (concerning the negative symptoms). The neuroleptcs can act in different cerebral regions, that canjustify the diversity ofboth, side-effects and therapeutical effects
Doutorado
Doutor em Saude Mental

APA, Harvard, Vancouver, ISO, and other styles

32

Bolwerk, Diógenes Alencar. "A (re)produção do espaço/Tocantins no contexto regional." Universidade Federal do Tocantins, 2014. http://hdl.handle.net/11612/264.

Full text

Abstract:

Este trabalho fez uma discussão sobre a produção e reprodução do espaço tocantinense no contexto regional. Sendo assim, o debate procurou empenhar-se na organização dos conceitos e teorias que alimentaram a temática regional, capitalismo, transporte, circulação e logística. A dissertação procurou dialogar com os autores regionais no que diz respeito às questões da Região Amazônica, do Tocantins, do transporte multimodal de cargas e de Palmas-TO dentro do contexto do desenvolvimento capitalista regional. O método adotado foi o materialismo histórico dialético que procurou investigar a realidade, por meio da dialética dos contrários para atingir a totalidade do espaço de maneira ambivalente, complementar e complexa. A abordagem foi qualitativa na construção das entrevistas estruturadas que foram realizadas com os sujeitos sociais. O trabalho ficou estruturado em três capítulos assim, distribuídos. O primeiro capítulo abordou a produção e reprodução do espaço do Tocantins no contexto da Amazônia, apresentando os conceitos de região, como também a discussão dos autores regionais sobre a Amazônia tocantinense e a capital Palmas. O segundo capítulo discutiu a reforma do Estado brasileiro, a crítica feita da teoria dos polos de crescimento e quando o planejamento regional analisou somente o plano econômico. O terceiro capítulo trabalhou a gestão dos transportes de cargas, a rodovia e a ferrovia, no contexto do Tocantins, os níveis de diferenciação e homogeneização da região, a tecnificação que propiciou a modernização da região, ou seja, o adensamento do capitalismo na região. A configuração da formação socioespacial de Palmas diante do contexto estadual e regional, culminado à cidade-fluxo. As discussões teóricas permitiram considerar três postos-chaves: uma abordagem na formação socioespacial da região com o entendimento do ciclo de produção e reprodução do capitalismo; um entendimento nas estratégias da teoria regulatória da economia para gerir a gestão da região; e por fim os circuitos econômicos e o debate regional.
This worked had a discussion about the production and reproduction of space Tocantins in its regional context. Thus, the debate sought to engage in the organization of the concepts and theories that fueled the regional theme, capitalism, transportation, distribution and logistics. The dissertation attempted to dialogue with regional authors with regard to the issues of the Amazon region, Tocantins, multimodal freight transportation and Palmas-TO within the context of regional capitalist development. The method adopted was dialectical historical materialism that sought to explore reality through the dialectic of opposites to achieve the full space of ambivalent and complex complementary way. The approach was qualitative in the construction of structured interviews that were conducted with social subjects. The work was structured in three chapters thus distributed. The first chapter covered the production and reproduction of space in the context of the Tocantins Amazon, presenting the concepts of region, as well as the discussion of regional authors on Amazon and the Tocantins capital Palmas. The second chapter discussed the reform of the Brazilian state, a critique of the theory of growth poles and when the regional planning only analyzed the economic plan. The third chapter worked the management of freight transportation, the highway and the railroad, in the context of Tocantins, the levels of differentiation and homogenization of the region, technicization that promoted the modernization of the region, the density of capitalism in the region. The configuration of socio-spatial formation Palmas on the state and regional context, culminated the city-flow. Theoretical discussions permitted to consider three key positions: an approach in socio-formation region with the understanding of the production and reproduction cycle of capitalism; an understanding of the strategies of regulatory economics theory to manage the management of the region; and finally the economic circuits and the regional debate.

APA, Harvard, Vancouver, ISO, and other styles

33

Brown, Mitic Constance Maria. "Flux associations and their relationship to the underlying heterogeneous surface characteristics." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35988.

Full text

Abstract:

This thesis consists of analysis of three different data sets: (i) Aircraft-based eddy correlation data collected above irrigated and non-irrigated agricultural land in Southern California during the California Ozone Deposition Experiment (CODE) summer 1991; (ii) micrometeorological tower data, collected over grape and cotton canopies as part of CODE; (iii) aircraft-based eddy correlation flux data above two grid sites in the Canadian boreal forest during the Boreal Ecosystem-Atmosphere Study (BOREAS), spring and summer of 1994 and 1996.
Results from the CODE aircraft data document composition and size of the dominant structures, which transport heat and gases (H2O, CO 2 and ozone) over water stressed and non-water stressed surfaces, and the relative frequency with which structures carrying only a single scalar, or given combinations of scalars, were encountered along the flight paths. Interpretation of results provides further evidence for the existence of a second (nonphysiological) sink for ozone. The relative preponderance of structures that carry moisture, carbon dioxide and ozone simultaneously, particularly in the gradient-up mode, reflects the importance of vegetation as co-located source/sink for these scalars. The detrending procedures described in this study may help to define a more effective separation between local and mesoscale events in biosphere-atmosphere interaction.
Results from the CODE tower data indicates a single vegetated ozone sink for the grape site, but a vegetated as well as a non-vegetated sink for the cotton site. For both sites, structures simultaneously transporting significant flux contributions of CO2, H2O, heat and ozone dominate during unstable conditions. During stable conditions, unmixed single flux structures dominated over cotton but not over grape. The results of this study contribute empirical evidence about the relationship between ozone uptake and the physical and physiological state of vegetation, as well as the limitations placed on eddy scales in simulation models.
Results from the BOREAS aircraft data shows a decoupling between the surface and the atmosphere, where the patterns of vegetation, greenness and surface temperature may be quite dissimilar to those of the fluxes of sensible heat, latent heat and---to a lesser degree---CO2. Reasons for this lie in the extraordinary boundary layer conditions, high vapour pressure deficit, moist soil and hot canopies, and the response of the vegetation to these conditions. Analysis of the coherent structure compositions to some extent permits the characterization of the different sources and sinks. Overall, this study shows the importance of understanding the various interacting components of soil, vegetation and atmosphere when attempting to design process-based models for predictions in 'micrometeorologiacally' complex ecosystems.

APA, Harvard, Vancouver, ISO, and other styles

34

Lacerda, Acioly Luiz Tavares de. "Transtorno obsessivo compulsivo : um estudo psicopatologico, neuropsicologico e de fluxo sanguineo cerebral regional (HMPAO-TC99M)." [s.n.], 2000. http://repositorio.unicamp.br/jspui/handle/REPOSIP/311612.

Full text

Abstract:

Orientador: Paulo Dalgalarrondo
Tese (doutorado) - Universidade Estadual de Campinas. Faculdade de Ciencias Medicas
Made available in DSpace on 2018-07-26T23:10:51Z (GMT). No. of bitstreams: 1 Lacerda_AciolyLuizTavaresde_D.pdf: 6959647 bytes, checksum: 1030a1c2f841133e5ef556992d9cd905 (MD5) Previous issue date: 2000
Resumo: Estudamos 16 pacientes adultos com diagnóstico de Transtorno Obsessivo Compulsivo [(segundo critérios diagnósticos da CID-lO (pesquisa) e do DSM-IV)], emparelhados por idade, gênero, escolaridade e lateralidade cerebral com um grupo de controles saudáveis (n = 17). Foi medido o Fluxo Sangüíneo Cerebral regional (FSCr) através da técnica de SPECT (99m TC-HMP AO), em estado de repouso, em ambos os grupos. Tanto os pacientes quanto os controles não utilizaram medicação psicotrópica no periodo de 30 dias anteriores à realização do exame. Avaliamos também o desempenho neuropsicológico de ambos os grupos, nas mesmas condições, através de um conjunto de testes: Teste da Trilha (parte A e B), Teste Dígito-Símbolo, Teste da Fluência Verbal Alternada, Mini Exame do Estado Mental, Figura Complexa de Rey-Osterrieth (cópia e desenho após 5 minutos) e Wisconsin Card Sorting Test (WCST). As variáveis psicopatológicas foram examinadas através das Escalas de Hamilton para Ansiedade e Depressão, Yale-Brown Obsessive Compulsive Scale (Y-BOCS), Impressão Clínica Global antes (CGI 1) e após o tratamento (CGI 2) e Global Assessment Scale (GAS). O grupo de pacientes apresentou um FSCr significativamente maior que o grupo controle nas seguintes regiões: Frontal Inferior Direita, Frontal Superior Direita e Tálamos Direito e Esquerdo. Além de um pior desempenho nos Testes de Fluência Verbal Alternada, WCST (menor número de respostas corretas, maior número de erros totais e perseverativos), Teste da Trilha (maior tempo de execução em ambas as partes e maior número de erros na parte B), Figura Complexa de Rey-Osterrieth (menor escore na cópia e maior tempo para o desenho após 5 minutos). Quando analisados os resultados âe SPECT, encontramos um hiperfluxo frontal (achado bastante relatado na literatura)' apenas à direita e nos Tálamos (achado menos freqüente na literatura). Nos testes neuropsicológicos, observamos um prejuízo em Funções Executivas, Funções Visuoespaciais e Fluência Verbal, resultados bastante robustos na literatura. Analisados conjuntamente, ps resultados de SPECT e da avaliação neuropsicológica, permitiu-nos concluir que, em concordância com a literatura, os pacientes com Transtorno Obsessivo Compulsivo, possivelmente, apresentam um prejuízo (aparentemente mais pronunciado nos pacientes com maior gravidade) no funcionamento das estruturas que compõem o Circuito Pré Frontal - Cíngulo - Estriado - Tálamo Cortical e no Hemisfério Cerebral Direito
Abstract: We compared 16 adult patients with Obsessive Compulsive Disorder (who met ICD-lO research criteria and DSM-IV diagnostic criteria), matched for age, sex, educational status, and handedness, to a health control group (n = 17). Regional Cerebral Blood Flow (rCBF) was measured in both groups by SPECT technique (99m Tc-HMPAO) in the resting state. Neither the patients nor the controls had been on pscychotropics for 30 days prior to the tests. We assessed the neuropsychological performance of both groups, in the same conditions, by means of a group oftests: Trail Making Test (A and B), Digit-Symbol Test, Verbal Fluency, Mini Mental State Examination, Rey-Osterrieth Complex Figure (copy and design after five minutes), and Wisconsin Card Sorting Test (WCST). Patients' symptomatology was assessed making use ofHamilton Anxiety and Depression Rating Scales, Yale-Brown Obsessive Compulsive Scale (Y-BOCS), Clinical Global Impression both before (CGI 1) and after treatment (CGI 2), and Global Assessment Scale (GAS). The patients showed a rCBF significantly higher than controls in the following regions: Inferior Right Frontal, Superior Right Frontal, and Right and Left Thalami. And a worse performance on Fluency Verbal Test, WCST (smaller number of correct responses, more total errors, and perseverative errors), Trail Making T est (larger time of execution in both parts, and more- errors in part B), Rey-Osterrieth Complex Figure (lower score in the copy and spend more time for design after five minutes). rCBF was increased in both Right Frontal Lobe (wich is dose agreement with findings from the literture) and Thalami - less frequendy reported in the literature. On the neuropsychological tests, the patients presented a deficit in Executive Functions, Visuospatial Functions, and Verbal Fluency. T~ftwongly agrees with other studies. Both fidings from the SPECT study and those derived from neuropsychological assessments are in close agreement with those reported in other studies and indica te that Obsessive Compulsive patients probably display an important deficit (associated with severity of illness) in the areas related to the functioning of Prefrontal-Cingulate-Striatum- Thalamus-Cortical circuit and Right Cerebral Hemiphere
Doutorado
Saude Mental
Doutor em Ciências Médicas

APA, Harvard, Vancouver, ISO, and other styles

35

STEFANELLI, GILLES. "Apport de l'analyse de l'adn par cytometrie en flux dans le bilan initial des cancers de la tete et du cou." Nice, 1994. http://www.theses.fr/1994NICE6550.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Korim, Willian Seiji. "Vias centrais purinérgicas envolvidas na regulação do fluxo sangüíneo muscular durante os comportamentos de alerta e defesa." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/47/47135/tde-06022007-175231/.

Full text

Abstract:

As reações de alerta e defesa compreendem ajustes cardiovasculares proporcionando um fluxo sangüíneo muscular adequado nas situações de \"luta ou fuga\". As vias centrais e os possíveis neurotransmissores envolvidos nestes ajustes permanecem ainda, em grande parte, desconhecidas. Neste estudo buscamos analisar a participação da neurotransmissão purinérgica e glutamatérgica no núcleo do trato solitário (NTS) na gênese da vasodilatação muscular durante reações de defesa e o papel das vias glutamatérgicas do NTS para o núcleo rostroventrolateral (RVL) nestas respostas. Ratos Wistar machos (250-350 g) foram anestesiados (uretana 600 mg/kg + alpha-chloralose 50 mg/kg, i.v.), paralisados (d-Tubocurarina, 0,5 mg/kg, i.v.) e ventilados artificialmente. Registramos a pressão arterial média (PAM), a freqüência cardíaca (FC) e o fluxo sangüíneo dos membros posteriores (FSMP). A condutância vascular dos membros posteriores (CVMP) foi determinada como a razão FSMP/PAM e expressa como percentagem do valor basal. A estimulação elétrica (EE; 150 MuA; 0,6 ms; 100 Hz; 6 s) do hipotálamo lateral provocou hipertensão, taquicardia e vasodilatação nos membros posteriores. A microinjeção bilateral de suramin (100 pmol/50 nl), um antagonista não específico de receptores P2x no NTS, reduziu a vasodilatação nos membros posteriores durante a EE do hipotálamo (173±19,0 vs 28±14,1% do basal) sem alterar as respostas pressora e taquicárdica. A microinjeção do agonista P2x alpha, beta-methylene ATP (100 pmol/50 nl) no NTS produziu hipotensão, bradicardia e vasodilatação dos membros posteriores. A microinjeção de suramin (100 pmol/50 nl) bloqueou a vasodilatação muscular (76±15,2 vs 9±2,1% do basal) e a hipotensão (-47±4,5 vs -6±2,0 mmHg). A microinjeção de ácido quinurênico (4 nmol/50 nl), um antagonista glutamatérgico ionotrópico não seletivo no NTS bloqueou, de forma semelhante ao suramin, a vasodilatação durante a EE do hipotálamo (134±21,5 vs 27±12,7% do basal) sem alterar as respostas pressora ou taquicárdica. O bloqueio bilateral no RVL com microinjeções de ácido quinurênico reduziu intensamente a resposta hipotensora (-60±6,1 vs -9±3,7 mmHg) e vasodilatadora (126±16,9 vs 17±4,6% do basal) provocada pelas microinjeções de alpha, beta-methylene ATP (100 pmol/50 nl) no NTS. O agonista purinérgico A2a, CGS21680 (20 pmol/50 nl) no NTS, evocou hipotensão, bradicardia e vasodilatação muscular de longa duração. O bloqueio do RVL com ácido quinurênico (4 nmol/50 nl) reduziu a hipotensão (- 41±4,7 vs -7±1,9 mmHg), a bradicardia (-33±9 vs -10±3,1 bpm) e a vasodilatação nos membros posteriores (81±5,6 vs 8±1,5% do basal). Estes resultados sugerem que a vasodilatação muscular nas repostas de defesa depende da ativação de receptores P2x e receptores glutamatérgicos no NTS. Ajustes cardiovasculares por ativação dos receptores purinérgicos P2x e A2a no NTS provocam vasodilatação muscular que depende da liberação de glutamato no RVL, provavelmente ativando interneurônios inibitórios ali presentes.
The electrical stimulation (ES) of the hypothalamus in the rat produces a well- defined pattern of cardiovascular adjustments including hypertension, tachycardia and skeletal muscle vasodilation. These hemodynamic responses can also be observed in natural conditions during fight and/or flight behaviors. However the neural pathways and possible neurotransmitters involved remain largely unknown. In this study we sought to determine the role of purinergic and glutamatergic receptors into the nucleus tractus solitarius (NTS) in the cardiovascular responses induced by hypothalamic ES, also we aimed to analyze the role of glutamatergic neural pathways from the NTS to the rostral ventrolateral medulla (RVLM) in these responses. Male Wistar rats (250-350 g) were anesthetized (urethane 600 mg/kg + alpha-chloralose 50 mg/kg, iv), paralyzed (d-tubocurarine 0.5 mg/kg, iv) and artificially ventilated. Mean arterial blood pressure (MAP), heart rate (HR) and hindquarter blood flow (HQBF) were recorded. Hindquarter vascular conductance (HQVC) was calculated as the ratio HQBF/MAP and expressed as percentage of baseline. Hypothalamic ES (6s trains, 0.6 ms square pulses, 100 Hz, 150 MuA) evoked a transitory hypertension, tachycardia and hindlimb muscle vasodilation. After bilateral microinjections of suramin (100 pmol /50 nl), a non-specific P2x receptor antagonist, into the NTS the hindlimb vasodilation was reduced (173±19.0 vs 28±14.1% of baseline), even so the transitory hypertension and tachycardia remained unchanged. A similar vasodilation reduction (134±21.5 vs 27±12.7% of baseline) was observed after microinjections of kynurenic acid bilaterally at the same NTS sites. Microinjections of the P2x receptor agonist alpha, beta-methylene ATP (100 pmol/50 nl) into the NTS produced hypotension, bradycardia and hindlimb muscle vasodilation. Bilateral microinjections of suramin at the same NTS site reduced the hypotension (-47±4.5 vs -6±2.0 mmHg) and the vasodilation (76±15.2 vs 9±2.1% of baseline). After bilateral microinjection of kynurenic acid into the RVLM, both hypotension (-60±6.1 vs -9±3.7 mmHg) and the vasodilation response (126±16.9 vs 17±4.6% of baseline) induced by alpha, beta- methylene ATP into the NTS were reduced. The A2a agonist CGS21680 (20 pmol/50 nl) into the NTS produced a long-lasting hypotension, bradycardia and hindlimb vasodilation. Bilateral RVLM glutamatergic blockade reduced the hypotension (-41±4.7 vs -7±1.9 mmHg), the tachycardia (-33±9.0 vs -10±3.1 bpm) and the muscle vasodilation (81±5.6 vs 8±1.5% of baseline) when CGS21680 was injected into the NTS. Therefore the results suggest that in alerting defense reaction, hindquarter vasodilation is mediated by NTS P2x and also by glutamatergic receptors into the intermediate NTS. Cardiovascular responses evoked by either P2x or A2a receptors stimulation in the NTS are mediated by glutamatergic synapses into the RVLM probably through activation of inhibitory interneurones in this area.

APA, Harvard, Vancouver, ISO, and other styles

37

Cardoso, Rubiane Daniele. "Uma análise do fluxo de comércio intrarregional no MERCOSUL utilizando um modelo gravitacional." Universidade Estadual do Oeste do Parana, 2011. http://tede.unioeste.br:8080/tede/handle/tede/2285.

Full text

Abstract:

Made available in DSpace on 2017-07-10T18:33:53Z (GMT). No. of bitstreams: 1 Rubiane Daniele Cardoso.pdf: 428454 bytes, checksum: 022d309962bc99a0da9d186b8d66b774 (MD5) Previous issue date: 2011-06-29
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
This paper search to analyze the effects of the formation of Mercosur Preferential Trade Agreement trade flows of member countries, using an extended gravity model that includes dummy variables for Mercosur, for UE and NAFTA (importants economic blocs), for the sectors of the economy and member country. Was used only the model of cross section data. The results show that Mercosur obtained the largest increases in trade among all regional integration schemes relevant to member countries, which highlights its importance for the members. When considering the analysis of the sectors, only agriculture had significant value, showing that the products were still predominant in this sector in the export of the Mercosur countries to all countries in the sample both in 1994, as in 2009. The analysis of dummy variables for the member countries showed that, even if the impact of the block was not uniform, the formation of MERCOSUR has had a significant effect on the pattern of exports of all its members, therefore, generally all of them experienced a significant increase in intrabloc exports during the period analyzed. With emphasis on the Paraguayan economy, that showed be strongly dependent on intraregional trade.
Esta dissertação procura analisar os efeitos da constituição do MERCOSUL nos fluxos de comércio dos países-membros, utilizando um modelo gravitacional estendido, que inclui variáveis dummy para o MERCOSUL, para UE e NAFTA (por serem blocos econômicos importantes), para os setores da economia e para cada país-membro. Foi utilizado apenas o modelo de dados seccionais (cross section). Os resultados mostram que o MERCOSUL obteve os maiores aumentos de comércio entre todos os esquemas de integração regionais relevantes para os países-membros, o que ressalta sua importância para os membros. Quando considerada a análise dos setores, apenas agricultura teve valor expressivo, mostrando que os produtos deste setor ainda foram predominantes na pauta de exportação dos países do MERCOSUL para todos os países da amostra tanto em 1994 quanto em 2009. A análise das variáveis dummy para os países-membros mostrou que, mesmo que o impacto do bloco não se tenha feito de maneira uniforme, a constituição do MERCOSUL surtiu efeitos significativos sobre o padrão de exportações de todos os seus integrantes, pois, de modo geral, todos eles experimentaram um aumento significativo das suas exportações intrabloco durante o período analisado. Com destaque para a economia paraguaia, que se mostrou fortemente dependente do comércio intrarregional.

APA, Harvard, Vancouver, ISO, and other styles

38

Tito, Fabiano Vieira. "Fluxo informacional do Sistema de Administração de Pessoal da Superintendência Regional de Ensino de Ubá/MG." Universidade Federal de Juiz de Fora (UFJF), 2018. https://repositorio.ufjf.br/jspui/handle/ufjf/7103.

Full text

Abstract:

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-08-22T19:09:06Z No. of bitstreams: 1 fabianovieiratito.pdf: 4187779 bytes, checksum: 4c5991e6628cbad313c9446985cdb758 (MD5)
Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-08-28T13:10:07Z (GMT) No. of bitstreams: 1 fabianovieiratito.pdf: 4187779 bytes, checksum: 4c5991e6628cbad313c9446985cdb758 (MD5)
Made available in DSpace on 2018-08-28T13:10:07Z (GMT). No. of bitstreams: 1 fabianovieiratito.pdf: 4187779 bytes, checksum: 4c5991e6628cbad313c9446985cdb758 (MD5) Previous issue date: 2018-01-29
A presente dissertação foi desenvolvida no âmbito do Mestrado Profissional em Gestão e Avaliação da Educação (PPGP), do Centro de Políticas Públicas e Avaliação da Educação da Universidade Federal de Juiz de Fora (CAEd/UFJF). O caso de gestão estudado discutiu a precisão dos inputs informacionais para o fluxo do Sistema Integrado de Administração de Pessoal (SISAP) da Superintendência Regional de Ensino de Ubá (SRE/Ubá); especificamente, o processo de codificação das informações transmitidas pelas instituições de ensino através dos Relatórios de Pessoal (RP1) e Guia de Ocorrência (GO). Os objetivos definidos para este estudo foram: pesquisar, analisar e aprimorar a qualidade informacional oriunda das instituições estaduais de ensino pertencentes à SRE/Ubá. Levantou-se como hipótese que os erros observados no processo de codificação das informações advindas das escolas podem causar prejuízo ao Estado ou ao servidor público. Para tanto, foi empregada como metodologia a pesquisa de campo, em termos quantitativos e qualitativos, de forma exploratória e descritiva, utilizando instrumentos de pesquisas como questionários e análises documentais. Os resultados confirmaram a existência do problema de pesquisa e demonstraram distorções comportamentais na rotina do fluxo informacional Escola/SISAP. Essas distorções foram principalmente em relação aos veículos de comunicação; à não empregabilidade do conhecimento institucional; e ao processo de dispersão desse conhecimento institucional. O Plano de Ação teve duas perspectivas de intervenções para as evidências apuradas: uma ideal (desejável) e a outra real (factível). O motivo para tal secção é a atual Calamidade Financeira decretada para o estado de Minas Gerais. O Plano ideal propôs, basicamente, a criação de um software para o preenchimento do RP1 e uma ferramenta de busca para o site oficial da SRE/Ubá. Por sua vez, a proposta factível está apoiada principalmente na educação informacional dos operadores do fluxo e na melhoria do processo de disseminação do conhecimento institucional. O objetivo principal dessas propostas de intervenções está no desenvolvimento da cultura informacional dos operadores do fluxo Escola/SISAP.
This dissertation was developed within the scope of the Professional Master in Management and Evaluation of Education (PPGP) of the Center for Public Policies and Education Evaluation of the Federal University of Juiz de Fora (CAEd/UFJF).The management case studied discussed the accuracy of the informational inputs to the flow of the Integrated System of Personnel Administration (SISAP) of the Regional Superintendence of Teaching of Ubá (SRE / Ubá); specifically the process of coding information transmitted by educational institutions through the Personnel Reports (RP1) and Occurrence Guide (GO). The objectives defined for this study were: to research, analyze and improve the information quality coming from state institutions of education belonging to the SRE/Ubá. The errors observed in the coding process of the information coming from the schools were hypothesized that they may cause damage to both, the State and the public servant. To do so, field research was used as a methodology in quantitative and qualitative terms, in an exploratory and descriptive way, using research instruments such as questionnaires and documentary analyzes. The results confirmed the existence of the research problem and demonstrated behavioral distortions in the routine of the School/SISAP’s information flow. These distortions were mainly in relation to the vehicles of communication; the non-employability of institutional knowledge and the dispersion process of the same institutional knowledge. The action plan had two perspectives of interventions for the evidences cleared: the ideal one (desirable) and the real one (feasible). The reason for such a section is the current financial calamity decreed by the State of Minas Gerais. The ideal Plan basically proposed the creation of software to fill out the RP1 and a search tool for the official SRE / Ubá website. The feasible proposal is based mainly on the informational education of flow operators and on improving the process of disseminating institutional knowledge. The main objective of these proposals of interventions is in the information culture development of the operators from the School/SISAP flow.

APA, Harvard, Vancouver, ISO, and other styles

39

Moraes, Daniel Umpierre de. "Efeitos sub-agudos de uma única sessão de exercício sobre o fluxo sanguíneo, modulação autonômica e pressão arterial na insuficiência cardíaca." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2007. http://hdl.handle.net/10183/12950.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Barros, Juliana Gonçalves de. "O papel da adenosina como reguladora do fluxo sanguíneo em ratos espontaneamente hipertensos jovens e adultos: efeitos do treinamento físico." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/5/5160/tde-08032010-134541/.

Full text

Abstract:

INTRODUÇÃO: Exercícios físicos são utilizados como terapia nãofarmacológica para o tratamento da hipertensão arterial e o treinamento físico (TF) por natação é reconhecido por produzir remodelamento cardíaco em animais experimentais. Entretanto, a ação vasodilatadora da adenosina (ado) resultante do exercício físico como prevenção e tratamento da hipertensão é pouco explorada. OBJETIVO: Avaliar remodelamento cardíaco e papel da adenosina na distribuição do fluxo sanguíneo para o miocárdio após treinamento físico em SHR. MÉTODO: 28 SHR machos babies e adultos foram submetidos ao TF aeróbio de natação, durante 10 semanas (5x/sem - 1h/dia). Foram utilizados protocolos de microesferas coloridas para avaliar fluxo sanguíneo, técnicas de morfologia para avaliar hipertrofia cardíaca e análises bioquímicas para verificar atividade de enzimas envolvidas na formação de adenosina. RESULTADOS: TF por natação atenuou a evolução da HA em SHR babies (S: 145±2; T: 140±2 mmHg), promoveu bradicardia de repouso em SHR adultos (S: 340±4; T: 321±6 bpm) e desenvolveu HC nos dois grupos (TB: 12%; TA: 10%). Na condição basal, o TF aumentou o FS coronário em SHR babies (S: 4745±2145; T: 6970±2374 mi/coração) e maior resposta vasodilatadora à infusão de adenosina foi observada (S: 18946±6685; T: 25045±7031 mi/coração). Nesse grupo o TF promoveu maior atividade da enzima 5-nucleotidase, levando à maior formação de adenosina (S: 0.45±0.09; T: 1.01±0.05). CONCLUSÃO: O TF de natação, além de desenvolver HC e apresentar maior hidrólise de AMP, promoveu aumento no FS coronário, sendo mostrado que desempenha um importante papel na regulação da hipertensão
ABSTRACT: Exercise training (ET) has been used as non-pharmacological therapy for hypertension treatment and the swimming physical training is recognized for yield cardiac remodeling in experiments. However, little is known on the effects of adenosine (Ado) resulting from ET as hypertension prevention and treatment. OBJECTIVE: To evaluate cardiac remodeling and the role of adenosine in cardiac blood flow distribution (BF) to the myocardium after aerobic ET on SHR. METHODS: 28 male SHR, babies and adults, were submitted to swimming training protocol during 10 weeks (5 times a week 1 h a day). Colored micro spheres protocols were used to evaluate blood flow, morphological techniques were used to evaluate cardiac hypertrophy and biochemical analysis were performed to verify enzyme activity in the adenosine formation. RESULTS: ET attenuated the evolution of hypertension in babies SHR group (S: 145±2; T: 140±2 mmHg), HR was lower in adults SHR (S: 340±4; T: 321±6 bpm) and CH increased in both groups (TB: 12%; TA: 10%). At basal condition, BF was increased in trained babies (S: 4745±2145; T: 6970±2374 mi/heart) and higher vasodilatation response were observed due to adenosine infusion (S: 18946±6685; T: 25045±7031 mi/heart). In this group, the ET promoted a higher 5- nucleotidase enzyme activity leading to a higher adenosine formation (S: 0.45±0.09; T: 1.01±0.05). CONCLUSION: The swimming training developed CH as well as increased adenosine formation, leading to higher coronary blood flow, being demonstrated its important role in hypertension regulation

APA, Harvard, Vancouver, ISO, and other styles

41

Ogunjemiyo, Segun Ojo. "Analysis of airborne flux measurements of heat, moisture and carbon dioxide, and their correlation with land cover types in BOREAS." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0024/NQ50231.pdf.

Full text

APA, Harvard, Vancouver, ISO, and other styles

42

Meregalli, André Felipe. "Hipoperfusão oculta em pacientes em pós-operatório de cirurgia de grande porte." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2005. http://hdl.handle.net/10183/7803.

Full text

Abstract:

Contexto: Nosso objetivo foi examinar se níveis seriados sangüíneos de lactato poderiam ser utilizados como preditores de desfecho. Métodos: Estudamos prospectivamente 44 pacientes cirúrgicos de alto risco, estáveis hemodinamicamente. Valores sangüíneos de lactato, pressão arterial média, freqüência cardíaca e débito urinário foram obtidos na admissão dos pacientes, 12, 24 e 48 horas após. Resultados: Os não-sobreviventes (n=7) tiveram níveis de lactato similares (3,1+2,3 mmol/l contra 2,2 +1,0 mmol/l, P= não significativo [NS]), mas tiveram níveis mais elevados após 12 horas (2,9 +1,7 mmol/l contra 1,6 + 0,9 mmol/l, P= 0,0012); após 24 horas (2,1 + 0,6 mmol/l contra 1,5 + 0,7 mmol/l, P= NS) e após 48 horas (2,7 + 1,8 mmol/l contra 1,9 + 1,4 mmol/l, P=NS) quando comparado com sobreviventes. A concentração arterial de bicarbonato aumentou significativamente nos sobreviventes e foi mais elevada do que nos não-sobreviventes após 24 horas (22,9 + 5,2 mEq/l contra 16,7 + 3,9 mEq/l, P=0,01) e após 48 horas (23,1+4,1 mEq/l contra 17,6±7,1 mEq/l, P= NS). A relação PaO2/FiO2 foi mais elevada inicialmente nos não-sobreviventes (334+121 mmHg contra 241+133 mmHg, P=0,03) e permaneceu elevada por 48 horas. Não houve diferenças significativas para pressão arterial média, freqüência cardíaca e oxigenação do sangue arterial entre sobreviventes e não-sobreviventes. As internações em UTI (40+42 horas contra 142+143 horas, P< 0,001) e hospitalar (12+11dias contra 24+17 dias, P=0,022) foram mais prolongadas para os não-sobreviventes do que para os sobreviventes. O Escore Fisiológico Agudo Simplificado II (Simplified Acute Physiology Score(SAPS) II) foi mais elevado entre os não-sobreviventes do que entre os sobreviventes (34+9 contra 25+14, P= NS). O débito urinário foi pouco menor entre os não-sobreviventes (P=NS). As áreas sob as curvas receiver operator characteristics foram maiores para o SAPS II e o lactato para predizer morte. Conclusão: Níveis elevados de lactato estão associados a uma maior taxa de mortalidade e de complicações pós-operatórias em pacientes cirúrgicos de alto risco, estáveis hemodinamicamente.

APA, Harvard, Vancouver, ISO, and other styles

43

Gomes, Vivian Carla da Silva. "Modelo experimental de estudo da hipertensão intra-abdominal: efeitos sobre o fluxo aórtico e pressão arterial sistêmica." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/5/5132/tde-07032017-142055/.

Full text

Abstract:

INTRODUÇÃO: A pressão intra-abdominal tem demonstrado possuir um importante efeito sobre a homeostase, podendo ser alterada por influência de diversos fatores. A literatura atual mostra que valores de pressão intra-abdominal acima de 200 mmHg podem ser observados mesmo durante fenômenos fisiológicos como a tosse. Relatos de caso recentemente publicados descrevem o colapso total da aorta abdominal decorrente da hipertensão intra-abdominal. Neste estudo, através de simulação, aferiu-se o grau de prejuízo ao fluxo através da aorta abdominal, bem como à pressão arterial sistêmica e pressão de perfusão abdominal durante o aumento progressivo da pressão intra-abdominal. OBJETIVOS: Estimar, através de simulação, como o aumento da pressão intra-abdominal pode influenciar o status hemodinâmico, comprometendo a pressão arterial sistêmica e o fluxo através da aorta abdominal. Averiguar a validade do uso da pressão de perfusão abdominal, na forma como é calculada atualmente, como parâmetro de monitorização hemodinâmica. MÉTODOS: Um sistema circulatório artificial possibilitou a simulação dos efeitos da pressão intra-abdominal sobre o fluxo através da aorta abdominal infrarrenal (representada por um tubo de silicone) bem como sobre a pressão arterial sistêmica. Condutos prostéticos foram colocados dentro do tubo de silicone (Dacron e endoprótese) para simular uma abordagem cirúrgica sobre a aorta. Cinco cenários de experimentação simulando situações clínicas foram definidos no ponto inicial do trabalho: hipotensão grave, hipotensão leve, normotensão, hipertensão leve e hipertensão grave. RESULTADOS: Foram analisados os dados obtidos durante o incremento progressivo da pressão intra-abdominal de 10 a 230 mmHg, considerando três diferentes espécimes (tubo de silicone / tubo de silicone + Dacron / tubo de silicone + endoprótese), cinco cenários de experimentação e sete variáveis (pressões sistólica e diastólica a montante e a jusante, fluxos sistólico e diastólico e pressão de perfusão abdominal). Conforme avaliação estatística através de análise de variância, observou-se que a pressão intra-abdominal tem uma clara influência em todas as variáveis de interesse (p < 0,001), independentemente do cenário de experimentação e do espécime considerado. Utilizando-se o teste de Tukey, na comparação dos espécimes dois a dois, observou-se que a combinação tubo de silicone + endoprótese apresentou a maior resiliência aos efeitos deletérios da pressão intra-abdominal na maior parte dos cenários de experimentação (p = 0,05), para todas as variáveis, exceto para a pressão de perfusão abdominal. A pressão de perfusão abdominal, calculada através da fórmula usada na literatura atual, apresentou as maiores reduções nos experimentos envolvendo o espécime tubo de silicone + endoprótese. CONCLUSÕES: A pressão intra-abdominal tem uma clara influência sobre todas as variáveis de interesse. A fórmula que descreve o cálculo da pressão de perfusão abdominal pode não levar em consideração a relação de dependência que pode existir entre a pressão arterial média e a pressão intra-abdominal
INTRODUCTION: The intra-abdominal pressure has been shown to possess an important effect over homeostasis and might be influenced by numerous conditions. The present medical literature shows that intra-abdominal pressure values above 200 mmHg might be observed, even in physiological phenomena as coughing. Recent case reports describe the collapse of abdominal aorta due to intra-abdominal hypertension. In this study, through simulation, we measured the hazard degree to the flow through infrarenal abdominal aorta as well as to systemic arterial pressure and abdominal perfusion pressure during progressive intra-abdominal pressure increments. OBJECTIVES: To estimate, through simulation, how the intra-abdominal pressure increment would influence the hemodynamic status, compromising the systemic arterial pressure and the flow through abdominal aorta. Evaluate the validity of the abdominal perfusion pressure usage, as it is calculated today, as a reliable parameter in hemodynamic monitoring. METHODS: An artificial circulatory system enabled the simulation of the intra-abdominal pressure effects over the flow through the infrarenal abdominal aorta (represented by a silicone tube) as well as over the systemic arterial pressure. Prosthetic conduits were set inside the silicone tube (Dacron or endoprosthesis) to simulate a surgical approach over the aorta. Five experiment categories simulating clinical scenarios were defined at the study starting point: severe hypotension, slight hypotension, normotension, slight hypertension and severe hypertension. RESULTS: The data obtained along the intra-abdominal pressure increment from 10 up to 230 mmHg were analyzed considering three different specimens (silicone tube / silicone tube + Dacron / silicone tube + endoprosthesis), five experimental scenarios and seven variables of interest (upstream and downstream systolic and diastolic pressures, systolic and diastolic flow and abdominal perfusion pressure). Statistical evaluation through variance analysis showed that the intraabdominal pressure has a clear influence in all variables of interest (p < 0,001), independently of the experimental scenario or the specimen considered. The Tukey test, in the comparison of the specimens two by two, showed that the combination silicone tube + endoprosthesis had the greatest resilience to the deleterious intra-abdominal pressure effect in most part of the experimental scenarios (p = 0,05) over all the interest variables, with exception to the abdominal perfusion pressure. The abdominal perfusion pressure, calculated by the formula used in the medical literature, presented the most significant decrement along the silicone tube + endoprosthesis experiments. CONCLUSIONS: The intra-abdominal pressure has a clear influence in all variables of interest. The formula which describes the abdominal perfusion pressure calculation might not consider the dependency relationship that might exist between mean arterial pressure and the intra-abdominal pressure

APA, Harvard, Vancouver, ISO, and other styles

44

Moreira, Daniel de Albuquerque Rangel. "Transplante hepático large-for-size porcino com modulação do fluxo venoso portal: estudo hemodinâmico, histológico e biomolecular." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/5/5132/tde-08042016-084814/.

Full text

Abstract:

INTRODUÇÃO: O tamanho ideal do fígado varia entre 0,8% a 4% do peso do receptor (graft to body weight ratio - GBWR). Em crianças com menos de 10 kg submetidas a transplante hepático com doador vivo encontramos frequentemente uma situação denominada large-for-size, que ocorre ao se implantar um enxerto com peso maior que 4% do peso corpóreo do receptor. A lesão de isquemia/reperfusão (LIR) é uma resposta inflamatória mediada pelas células de Kupffer, principais responsáveis pela liberação de espécies reativas de oxigênio no parênquima hepático. Além disso, a célula de Kupffer libera citocinas pró-inflamatórias como TNF-alfa, IL-1 e IL-6 que recrutam polimorfonucleares sistêmicos e linfócitos T-CD4+ perpetuando a lesão mesmo após o fluxo sanguíneo estar restabelecido. O hipofluxo portal pode piorar a LIR na situação large-for-size. Desta forma, um shunt mesentérico-cava tentando direcionar o fluxo para a veia porta poderia ser benéfico nesta situação. MÉTODOS: Dezesseis porcos LandraceLargewhite pesando entre 17 - 38 kg foram submetidos a transplante de fígado. Foram distribuídos em três grupos: controle (CTRL), large-for-size (LFS) e shunt (SHUNT). Foi aferido o fluxo venoso portal, arterial hepático e colhido material para estudo histológico e biomolecular uma hora após a reperfusão. A relação entre o fluxo venoso portal do receptor para o fluxo venoso portal doador (rFVP) foi utilizada para se correlacionar com a gravidade da isquemia/reperfusão. Foram realizadas biópsias uma hora após o transplante para microscopia óptica e TUNEL além de quantificar a expressão dos genes da iNOS, eNOS, IL-6, BAX e BCL, c-fos/c-jun, ICAM e TNF-?. RESULTADOS: O GBWR foi maior nos grupos LFS e SHUNT (3,45 vs. 5,06 e 6,03; p=0,009). Quando comparamos isoladamente receptores e doadores por grupo houve diferença no fluxo portal somente nos grupos LFS (890 ± 203 mL / min vs. 458 ± 119 mL / min, p=0.0034) e SHUNT (1003 ± 5,3 mL/min vs. 495 ± 277 mL/min; p=0,0031). A rFVP foi próxima de 1 no grupo CTRL e significativamente maior que nos grupos LFS e SHUNT (p=0,03). O fluxo arterial hepático foi significativamente menor no grupo SHUNT (62,16 ± 31 mL / min) quando comparado com grupo CTRL (140.4 ± 53.88 mL / min) e LFS (142 ± 55.41 mL / min), p=0,02. A IL-6 e BAX foram menos expressas no grupo CTRL (p=0,05 e p=0,002). Houve uma relação linear entre a expressão dos genes BAX, TNF-alfa e eNOS com a rFVP (p=0,02; p=0,02 e p=0,009 respectivamente). Na avaliação histológica observou-se índice de isquemia e reperfusão semelhante entre os grupos CTRL e SHUNT mas menor em relação ao LFS, 3, 3,5 e 7 respectivamente (p=0,04). CONCLUSÕES: O transplante large-for-size acarreta hipofluxo portal relativo, e isto pode estar relacionado a um maior dano hepatocitário com acentuação da lesão de isquemia-reperfusão. A presença de um shunt entre a veia cava inferior e a veia mesentérica superior não conseguiu aumentar o influxo de sangue para o fígado de maneira persistente e pode estar implicado na diminuição do fluxo arterial hepático. No entanto, o aumento temporário do influxo portal pode estar relacionado a atenuação de algumas características da LIR no transplante large-for-size
INTRODUCTION: The optimum size of the liver graft for transplantation varies between 0.8% and 4% of the weight of the recipient (graft to body weight ratio - GBWR). In children with less than 10 kg who undergo liver transplantation with living donor a disorder called large-for-size (LFS) often occurs, when a graft weighing more than 4% of body weight of the recipient is implanted. Ischemia / reperfusion injury (IRI) is an inflammatory response mediated by Kupffer cells, mainly responsible for the release of reactive oxygen species in the liver parenchyma. In addition, Kupffer cells releases proinflammatory cytokines such as TNF-alfa, IL-1 and IL-6 that recruit systemic polymorphonuclear cells and T-CD4 + perpetuating this injury even after the blood flow is restored. Low portal flow may worsen IRI in LFS situation. So, a mesocaval shunt directing the flow to portal vein should be beneficial in this condition. METHODS: Sixteen Landrace/Largewhite pigs weighing approximately 20 kg (17-38 kg) underwent liver transplantation. They were divided into three groups: control (CTRL), large-for-size (LFS) and shunt (SHUNT). Portal venous flow was measured and liver and blood collected for histological and biomolecular study one hour after reperfusion. The relationship between the portal venous flow from the recipient to the donor portal venous flow (rFVP) was used to establish correlations with the parameters of ischemia and reperfusion. Biopsies were performed one hour after transplant to assess ischemia/reperfusion injury, TUNEL and quantify the following genes expression: iNOS, eNOS, IL-6, BAX and BCL c-fos / c-jun, ICAM, and TNF-alfa. RESULTS: GBWR was higher in groups LFS and SHUNT than CTRL (3.45 vs. 5.06 and 6.03; p=0.009). When compared separately by group recipients and donors difference in portal flow was observed only in LFS groups (890 ± 203 mL / min vs. 458 ± 119 mL / min, p=0.0034) and SHUNT (1003 ± 5.3 mL / min vs. 495 ± 277 mL / min, p=0.0031). rFVP was close to 1 in the CTRL group and significantly higher than the LFS and SHUNT groups (p= 0.03). Hepatic artery blood flow was significantly lower in SHUNT group (62.16 ± 31 mL / min) compared with CTRL group (140.4 ± 53.88 mL / min) and LFS (142 ± 55.41 mL / min), p= 0.02. IL-6 and BAX were expressed less in the CTRL group (p=0.05 and p=0.002). There was a linear relationship between the BAX, TNF-alfa and eNOS with rFVP (p=0.02, p=0.02 and p=0.009 respectively). Histological evaluation showed similar ischemia-reperfusion index between CTRL and SHUNT groups but lower values in compare to LFS group, 3, 3.5 and 7 respectively (p=0.04). CONCLUSIONS: The largefor-size liver transplantation leads to a relative low portal venous flow and this can be related to greater hepatocyte damage with accentuation of ischemia-reperfusion injury. The presence of a shunt between the inferior vena cava and the superior mesenteric vein could not increase the inflow of blood to the liver persistently and may be implicated in decreased hepatic artery blood flow. However, the temporary increase in portal inflow may be related to mitigation of some characteristics of IRI in large-for-size liver transplantation

APA, Harvard, Vancouver, ISO, and other styles

45

Junior, Antonio Aurelio de Paiva Fagundes. "Estudo do fluxo sanguíneo regional e dos marcadores de perfusão tecidual em pacientes com insuficiência cardíaca em uso de balão intra-aórtico." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/5/5131/tde-10122013-102948/.

Full text

Abstract:

INTRODUÇÃO: O balão intra-aórtico (BIA) representa o mecanismo de assistência ventricular mais frequentemente utilizado em pacientes com insuficiência cardíaca (IC), no Brasil. OBJETIVO: Neste trabalho, avaliamos a ação do BIA sobre o fluxo sanguíneo carotídeo e braquial, além do seu efeito sobre os marcadores de perfusão tecidual e sobre o peptídeo natriurético cerebral (BNP). MÉTODOS: Entre julho de 2006 e maio de 2009, 33 pacientes foram avaliados, sendo 10 excluídos. Os pacientes foram inicialmente mantidos com o BIA em modo 1:1, com insuflação máxima, para a fase inicial do estudo (condição 1). Realizou-se coleta de gasometria arterial, venosa central e BNP (condição EXA1). Foi realizada ultrassonografia vascular de alta definição, para captação de imagens das curvas de velocidade de fluxo sanguíneo, e medida dos diâmetros arteriais sistólico e diastólico (condição MD1). Em seguida, foi avaliada a resposta vascular frente à hiperemia reativa (condição HR1). Realizado o estudo na condição 1, o BIA foi modificado para 1:3 com insuflação mínima (condição 2) e todos os exames laboratoriais (condição EXA 2) e ultrassonográficos (condição MD2 e condição HR2) foram repetidos. Após a condição 2, passou-se à condição 3, na qual o BIA foi novamente modificado para a assistência 1:1, com insuflação máxima. Da mesma forma que nas condições anteriores, foram realizados exames laboratoriais (condição EXA 3) e a ultrassonografia (condição MD3 e HR3). A avaliação estatística foi realizada através da análise de variância para medidas repetidas e o uso do teste não paramétrico de Friedman. RESULTADOS: A idade média dos pacientes selecionados foi de 49,7 ± 13 anos, sendo 17 (74%) do sexo masculino e 6 (26%) do sexo feminimo. Quanto à etiologia, 9 (39%) pacientes eram portadores de miocardiopatia isquêmica, 8 (34%) miocardiopatia dilatada idiopática, 4 (17%) tinham etiologia chagásica e 2 (8%) por valvopatias. A fração de ejeção, estimada pelo ecocardiograma variou de 14 a 40%, com Resumo média de 22 +-8%. Nove pacientes (39%) encontravam-se em fila para transplante cardíaco, no momento da inclusão no protocolo, e a mortalidade durante a internação foi de 60,8%. Analisados os dados laboratoriais, não houve, entre as três medidas realizadas, diferença com significância estatística nos valores de bicarbonato arterial (BIC), assim como, nos valores de excesso de base (BE). Também não detectamos mudanças na saturação venosa central de oxigênio (SVcO2), no nível sérico de BNP e no gradiente venoarterial de CO2(DeltaPCO2). Os resultados das análises da velocidade de fluxo, índice de fluxo carotídeo e integral velocidade-tempo na condição MD1, MD2 e MD3 não revelaram diferenças estatisticamente significantes. Analisado o território braquial, considerando a velocidade de fluxo braquial não houve diferença entre a condição MD1 e a condição MD2 e entre a condição MD1 e a condição MD3. Entretanto, identificamos diferença entre as condições MD2 e MD3 (p=0,01). Não encontramos diferença com significância entre as três condições considerando o índice de fluxo e a integral velocidade-tempo. Na prova de hiperemia reativa não encontramos alteração entre as condições HR1, HR2 e HR3, quando avaliamos a velocidade de fluxo, o índice de fluxo e a integral velocidade-tempo. A dilatação fluxo mediada da artéria braquial (DILA) encontrava-se alterada desde o momento inicial, porém o protocolo não revelou alterações entre HR1, HR2 e HR3. CONCLUSÃO: Em pacientes com insuficiência cardíaca, a assistência com o BIA não modificou o fluxo sanguíneo regional em território cerebral e muscular esquelético avaliados pelo fluxo da carótida e artéria braquial, respectivamente. Da mesma forma, não houve alteração da perfusão tecidual e função cardíaca avaliados pelos marcadores do metabolismo oxidativo e sobrecarga hídrica utilizados. A função endotelial avaliada na condição de duplo pulso de fluxo da artéria braquial propiciada pela assistência circulatória do BIA evidenciou-se alterada com dimunuição da reatividade vascular
BACKGROUND: The intra-aortic balloon (IAB) represents the mechanism of ventricular assist more often used in patients with heart failure (HF) in our midst. OBJECTIVE: In this study, we evaluated the action of the IAB on the carotid and brachial blood flow, in addition to its effect on markers of tissue perfusion and the brain natriuretic peptide (BNP). METHODS: Between July 2006 and May 2009, 33 patients were evaluated, 10 were excluded. Patients were initially maintained with the IAB in 1:1 mode with maximum insufflation, for the initial phase of the study (condition 1). Held collection of arterial and central venous blood gases, and BNP (condition EXA1). Vascular ultrasonography was performed in high definition, to capture images of the curves of blood flow velocity, and measurement of systolic and diastolic arterial diameters (condition MD1). Then we evaluated the vascular responses to reactive hyperemia (condition HR1). Conducted the study in condition 1, the IAB was changed to 1:3 with minimal insufflation (condition 2) and all laboratory tests (condition EXA 2) and ultrasound (condition MD2 and HR2) were repeated. After the second condition, the IAB was again modified to 1:1, with maximum insufflation (condition 3). Similarly to the previous conditions, laboratory tests (condition EXA 3) and ultrasound (condition MD3 and HR3) were performed. Statistical evaluation was performed by analysis of variance for repeated measures and the use of Friedman nonparametric test. RESULTS: The mean age of the selected patients was 49.7 +- 13 years, 17 (74%) males and 6 (26%) were females. Concerning etiology, 9 (39%) patients had ischemic cardiomyopathy, 8 (34%), idiopathic dilated cardiomyopathy, 4 (17%) had Chagas disease and 2 were (8%) related to valvulopathy. Ejection fraction estimated by echocardiography ranged from 14 to 40%, with a mean of 22 +- 8%. Nine patients (39%) were in line for a heart transplant at the time of inclusion in the protocol and mortality during hospitalization was 60.8%. Analyzed laboratory data, among the three measurements, there was not statistically significant difference in the values of arterial bicarbonate (BIC) and base excess (BE). We also did not detect changes in central venous oxygen saturation (SCVO2) or in serum BNP level and venoarterial carbon dioxide gradient (DeltaPCO2). The results of the analysis of carotid flow velocity, index of carotid flow and velocity time integral in condition MD1, MD2 and MD3 revealed no statistically significant difference. Examined the brachial territory, there was no difference between the condition MD1 and MD2 and between MD1 and MD3 considering the flow velocity. However, there was difference between conditions MD2 and MD3 (p = 0.01). We found no significant difference between the three conditions considering the brachial flow index and velocity time integral. The flow-mediated dilation of the brachial artery (FMD) found itself changed from the initial moment, but the protocol does not reveal changes between HR1, HR2 and HR3. CONCLUSION: In heart failure patients, assistance with the BIA did not alter regional blood flow in brain and skeletal muscle territory assessed by flow carotid and brachial artery, respectively. Likewise, there was no change in tissue perfusion and cardiac function assessed by markers of oxidative metabolism and fluid overload used. Endothelial function evaluated on condition of dual pulse brachial artery flow provided by BIA circulatory support showed up changed with decreased vascular reactivity

APA, Harvard, Vancouver, ISO, and other styles

46

Eloi, Juliana Cristina. "Volume de fluxo sanguíneo na artéria mesentérica superior aferido pela ultrassonografia com doppler em crianças e adolescentes." Pontifícia Universidade Católica do Rio Grande do Sul, 2011. http://hdl.handle.net/10923/4739.

Full text

Abstract:

Made available in DSpace on 2013-08-07T19:07:15Z (GMT). No. of bitstreams: 1 000432333-Texto+Completo-0.pdf: 676720 bytes, checksum: 8a62c2e5d19c905c08550681888a157a (MD5) Previous issue date: 2011
OBJECTIVE To measure superior mesenteric artery blood flow (SMABF) in healthy children and adolescents in age groups of greater Crohn's disease (CD) incidence. To assess the interobserver variability. MATERIAL AND METHODS The superior mesenteric artery blood flow was prospectively measured using pulsed Doppler ultrasound in 60 volunteers without any chronic diseases. Participants were divided into two groups: children (5-9 years) and adolescents (10-17 years). All were classified according to weight and blood pressure. Each volunteer was examined by two experienced radiologists. Each examiner made three measurements to decrease the chance of random errors. The Student t test was used to evaluate the difference between examiners, and Bland-Altman plots, to evaluate agreement. SMABF was compared with anthropometric data and hemodynamic parameters, and their correlation was determined using the Spearman coefficient. Multiple linear regression was used to control for confounding factors and to evaluate factors independently associated with SMABF. The difference between groups was significant at p<0. 05.RESULTS The average age of participants was 12. 2 years; 21 (35%) were in the 5-9 group, and 10 (65%), in the 10-17 group. SMABF was significantly lower in the group of children (mean=556 ml/min; SD=122 ml/min) than among adolescents (mean=775 ml/min; SD=311 ml/min) (p<0. 001). Participants with normal weight had a lower SMABF value than obese individuals. No significant differences were found between overweight and obese patients or patients with normal weight. Waist circumference and systolic blood pressure also were significantly associated with the SMABF. However, after multivariate analysis, only the body surface was significantly associated with SMABF, and the greater the body surface, the greater the SMABF. CONCLUSIONS: The SMABF is directly associated with the body surface. Studies are needed with CD activity and remission, considering the SMABF according to body surface in normal subjects for this parameter can be used as a marker of activity. Pulsed Doppler ultrasound was a feasible and accurate method for the pediatric population.
Objetivo: Avaliar o volume de fluxo na artéria mesentérica superior (VFAMS) através da ultrassonografia com Doppler pulsátil em crianças e adolescentes sadios na faixa etária de maior incidência de doença de Crohn. Avaliar a concordância interobservador do método. Materiais e métodos: O estudo foi aprovado pelo comitê de ética médica e foi colhido o termo de consentimento informado. Estudou-se prospectivamente o volume de fluxo da artéria mesentérica superior em 60 voluntários sadios, dividido em 2 grupos de acordo com a faixa etária: crianças (5-9 anos) e adolescentes (10-17 anos). Todos foram classificados segundo o estado nutricional e pressórico. Todos os voluntários foram examinados por 2 radiologistas independentes com longa experiência e foram realizadas três medidas. Resultados: Os 60 indivíduos tinham idade média de 12,2 anos, sendo 21 entre 5 e 9 anos (35%) e 39 entre 10 e 17 anos (65%). O VAMS foi significativamente menor nas crianças (média=556 ml/min; DP=122ml/min) do que nos adolescentes (média=775ml/min, DP=311 ml/min), com p<0,001. Os eutróficos também apresentaram o VFAMS menor do que os obesos. Os indivíduos com sobrepeso não apresentaram diferença significativa, tanto em relação aos eutróficos quanto aos obesos. Apenas a superfície corporal ficou associada significativamente com o VFAMS. Dessa forma, quanto maior a superfície corporal, maior será o VFAMS. Conclusões: O VFAMS determinado pela US com Doppler a cores é diretamente proporcional à superfície corporal.

APA, Harvard, Vancouver, ISO, and other styles

47

Guglielmin, Júlio Zago. "Efeitos da estimulação elétrica nervosa transcutânea e da corrente interferencial sobre o comportamento do metaboreflexo muscular." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2013. http://hdl.handle.net/10183/97210.

Full text

Abstract:

Introdução: Nós havíamos demonstrado que a estimulação elétrica nervosa transcutânea (TENS) e a estimulação elétrica interferencial (IES) aumentam o fluxo sanguíneo periférico através da inibição do sistema nervoso simpático. Objetivo: A proposta desse estudo foi de comparar os efeitos do TENS e IES sobre a condição controle para examinar o efeito da ativação do metaboreflexo e variabilidade da frequência cardíaca em indivíduos saudáveis. Métodos: Onze sujeitos saudáveis (idade 26 ± 2.8 anos) foram randomizados para TENS, IES ou controle (mesmo protocolo sem aplicação de corrente) aplicado na região ganglionar. Pressão arterial media (MBP), frequência cardíaca (HR), fluxo sanguíneo da panturrilha (CBF) e resistência vascular periférica (CVR) foram mensuradas através de um protocolo de exercício (submáximo estático com handgrip) e períodos de recuperação com ou sem oclusão circulatória pós-exercício (PECO+ e PECO-). O controle do metaboreflexo muscular e a resistência vascular periférica foram estimados através da subtração da área sob a curva (AUC) quando a circulação foi ocluída da AUC sem oclusão circulatória. Resultados: No pico do exercício o aumento da MBP foi atenuado tanto pelo TENS quanto pela IES (p>0,05), o qual persistiu durante PECO+ e PECO-. IES promoveu um aumento do CBF e diminuição da CVR durante o exercício e recuperação comparado com o TENS. Assim como, IES induziu uma redução maior no metobareflexo muscular estimado nos sujeitos controle (placebo 26 ± 5 unidades, TENS 14 ± 4 vs IES 9 ± 2, p<0,01). A análise da HRV mostrou uma melhora superior no balanço simpato-vagal com IES do que com o TENS nos indivíduos. Conclusão: A aplicação aguda da IES parece ter uma eficácia superior à atenuação da pressão sanguínea e respostas vasoconstritoras durante o exercício e ativação do metaboreflexo nos sujeitos saudáveis com

APA, Harvard, Vancouver, ISO, and other styles

48

Takasao, Shinsuke. "Fundamental Magnetohydrodynamic Processes of Solar Flares: Formation of Flare-productive Regions and Evolution of Flare Loops." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215316.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Martinêz, Daniel Godoy. "Efeito do treinamento físico no controle neurovascular em pacientes portadores de síndrome isquêmica miocárdica instável." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/5/5131/tde-18022011-141138/.

Full text

Abstract:

INTRODUÇÃO: O infarto agudo do miocárdio está associado à hiperativação simpática e diminuição do fluxo sanguíneo muscular (FSM). Por outro lado, tem sido documentado que o treinamento físico promove importantes adaptações autonômicas e vasculares no indivíduo. O objetivo deste estudo foi testar a hipótese de que o treinamento físico diminuiria a atividade nervosa simpática muscular (ANSM) e aumentaria o FSM em repouso e durante o exercício físico em pacientes com Síndrome Isquêmica Miocárdica Instável (SIMI). MÉTODOS: Foram incluídos no estudo, 63 pacientes internados na Unidade Clínica de Coronariopatia Aguda diagnosticados com SIMI. Um mês após o evento isquêmico, 51 pacientes continuaram o seguimento e foram alocados, consecutivamente, em 2 grupos: treinamento físico (SIMI-TF, n=25, 54±1 anos), e sedentário (SIMI-Sed, n=26, 52±2 anos). Ao final do estudo, 14 pacientes do grupo SIMI-TF e 20 pacientes do grupo SIMI-Sed finalizaram o protocolo experimental. Esses pacientes foram comparados a um grupo controle saudável (n=13, 49±1anos). A ANSM foi medida pela técnica de microneurografia. O FSM foi avaliado por pletismografia de oclusão venosa, a pressão arterial (PA) foi medida pelo método oscilométrico indireto e a frequência cardíaca pelo eletrocardiograma. Todas as avaliações foram realizadas no basal, durante a fase de internação hospitalar e, no basal e durante 3 minutos de exercício físico de preensão de mãos (30% da contração voluntária máxima) no período de seguimento do estudo (1º., 3º.e 7º. mês após o evento isquêmico). O treinamento físico foi realizado em cicloergômetro, 3 vezes por semana, durante 6 meses. RESULTADOS: Durante a fase de internação hospitalar, a ANSM basal foi significativamente maior (65±2 vs. 32±2 disparos/100batimentos, p<0,001) e a condutância vascular no antebraço (CVA= FSM/PAmédia) foi significativamente menor (1,91±0,1 vs. 2,99±0,38 unidades, p<0,001) no grupo SIMI em relação ao grupo Controle. Comportamento semelhante foi observado 1 mês após o evento isquêmico, a ANSM continuou aumentada (64±3 vs. 62±4 vs. 32±2 disparos/100batimentos, p<0,001, respectivamente) e a CVA diminuída (1,73±0,1 vs. 1,72±0,1 vs. 2,99±0,4 unidades, p<0,001, respectivamente) nos grupos SIMI-Sed e SIMI-TF em relação ao grupo Controle. Durante o exercício de preensão de mãos, os níveis de ANSM foram maiores (71±4 e 69±4 vs. 43±3 disparos/100batimentos, p<0,001, respectivamente) e a CVA foi menor (1,60±0,1 e 1,59±0,2 vs. 3,53±0,47 unidades, p<0,001, respectivamente), nos grupos SIMI-Sed e SIMI-TF em relação ao grupo Controle. Após o treinamento físico, a ANSM basal diminuiu no grupo SIMITF (62±4 vs. 40±3 disparos/100batimentos, p=0,02), atingindo níveis semelhantes ao grupo Controle (40±3 vs. 32±2 disparos/100batimentos, p=0,24, respectivamente). Durante o exercício físico, a ANSM diminuiu no grupo SIMI-TF (72±5 vs. 60±5 disparos/100batimentos, p<0,001). Porém, a CVA não foi significativamente modificada tanto no basal como durante o exercício no grupo SIMI-TF. Nenhuma alteração significativa foi observada na ANSM e CVA do grupo SIMI-Sed, tanto em repouso como durante o exercício. CONCLUSÕES: Em pacientes com SIMI, o treinamento físico normalizou a ANSM basal e diminuiu seus níveis durante o exercício, porém, não modificou o FSM. Como a ativação simpática está relacionada com pior prognóstico, nossos resultados ressaltam a importância clínica do treinamento físico em pacientes após SIMI
Introduction: The myocardial infarction is associated with sympathetic hiperactivation and reduced forearm blood flow (FBF). On the other hand, the exercise training leads to important autonomic and vascular adaptations. The purpose of this study was to test the hypothesis that exercise training would decrease the muscle sympathetic nerve activity (MSNA) and would increase the FBF at rest and during exercise in patients with acute coronary syndrome (ACS). Methods: Sixty-three patients admitted to the coronary intensive care unit with ACS were studied. One month after ischemic event, 51 patients continued the follow-up study and were allocated consecutively in two groups: exercise training (ACS-ET, n=25, 54±1 years) and sedentary (ACSSed, n=26, 52±2 years). At the end of the study, 14 patients in the group ACS-ET and 20 patients in the group ACS-Sed concluded the experimental protocol. These patients were compared to a control group of healthy subjects (n=13, 49±1 years). The MSNA was measured by microneurography technique. The FBF was measured by venous occlusion plethysmography, the blood pressure (BP) was measured by indirect oscillometric method and the heart rate was measured by electrocardiogram. All measurements were done at rest condition during inpatient phase and at rest condition and during 3 minutes of handgrip exercise (30% of maximum voluntary contraction) during outpatient follow-up (1st, 3rd and 7th months after the ischemic event). The exercise training was performed on a cycle ergometer 3 times per week for 6 months. RESULTS: During inpatient phase, the MSNA at rest was significantly higher (65±2 vs. 32±2 bursts/100heart beats, p<0.001) and forearm vascular conductance (FVC=FBF/mean BP) was significantly lower (1.91±0.1 vs. 2.99±0.38 units, p<0.001) in ACS group when compared to control group. One month after the ischemic event, the MSNA remained significantly higher (64±3 vs. 62±4 vs. 32±2 bursts/100 heart beats, p<0,001) and the FVC continue significantly lower (1.73±0.1 vs. 1.72±0.1 vs. 2.99±0.4 units, p<0,001) in the ACS-Sed and ACS-ET groups when compared to the control group. During handgrip exercise, the MSNA levels were significantly higher (71±4 and 69±4 vs. 43±3 bursts/100heart beats, p <0.001, respectively) and FVC levels were significantly lower (1.60±0.1 and 1.59± 0.2 vs. 3.53 ± 0.47 units, p <0.001, respectively) in the ACS-Sed and ACS-ET groups when compared to the control group, respectively. After exercise training, the MSNA at rest decreased significantly in the group ACS-ET (62±4 vs. 40±3 bursts/100 heart beats, p=0.02), reaching similar levels to those found in the control group (40±3. vs. 32±2 burts/100 heart beats, p= 0.24, respectively). During handgrip exercise the MSNA decreased significantly in ACS-ET group (72±5 vs. 60±5 bursts/100 heart beats, p <0.001). However, the FVC was not significantly changed at rest and during exercise in ACS-ET group. No significant change was observed in MSNA and FVC in ACS-Sed group at rest and during exercise. CONCLUSIONS: In patients with ACS, the exercise training normalized the MSNA at rest and decreased their levels during exercise, but no change was observed in the FVC. Since sympathetic activation is related to poor prognosis, our results highlight the clinical importance of ET in patients with ACS

APA, Harvard, Vancouver, ISO, and other styles

50

Lobo, Denise Moreira Lima. "Controle quimiorreflexo da atividade nervosa simpática e do fluxo sanguíneo muscular em pacientes com insuficiência cardíaca e distúrbio respiratório do sono." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/5/5131/tde-06022017-111017/.

Full text

Abstract:

Introdução: Os distúrbios respiratórios do sono são comuns em pacientes com insuficiência cardíaca. Estudos recentes mostram que pacientes com insuficiência cardíaca apresentam resposta vasoconstritora muscular paradoxal durante a estimulação dos quimiorreceptores centrais e periféricos e que essa resposta está associada à disfunção endotelial e à exacerbação nervosa simpática. Porém, o que não se conhece é se essa resposta está intensificada em pacientes com a coexistência de insuficiência cardíaca e distúrbio respiratório do sono. Objetivos: Testar a hipótese de que: 1) A resposta de fluxo sanguíneo muscular (FSM) durante a hipercapnia e a hipóxia seria menor em pacientes com insuficiência cardíaca e distúrbio respiratório do sono que em pacientes com insuficiência cardíaca sem distúrbio respiratório do sono; e 2) A resposta vasoconstritora mais exacerbada em pacientes com a coexistência de insuficiência cardíaca e distúrbio respiratório do sono estaria associada à disfunção endotelial e/ou à resposta exagerada da atividade nervosa simpática muscular (ANSM). Métodos: Foram avaliados, consecutivamente, 90 pacientes com insuficiência cardíaca, classe funcional II-III (New York Heart Association). Destes, 41 preencheram os critérios de inclusão e, após o exame de polissonografia, foram alocados em dois grupos, de acordo com o índice de apneia e hipopneia (IAH): Grupo IC (IAH < 15 eventos/hora; n=13; 46 (39-53) anos) e Grupo IC+DRS (IAH >= 15 eventos/hora; n=28; 57 (54-61) anos). O consumo de oxigênio no pico do exercício ( 2 pico) e a fração de ejeção do ventrículo esquerdo (FEVE) foram avaliados pelo teste cardiopulmonar em esforço e pela ecocardiografia transtorácica basal, respectivamente. Os FSM do antebraço e da panturrilha (FSMab e FSMp, respectivamente) foram avaliados pela pletismografia de oclusão venosa e a ANSM pela técnica de microneurografia. A pressão arterial média (PAM) e a frequência cardíaca (FC) foram avaliadas batimento a batimento de forma não invasiva (Finometer® PRO). O quimiorreflexo central foi estimulado por meio da inalação de uma mistura gasosa hipercápnica (7% CO2 e 93% O2) e o quimiorreflexo periférico por meio da inalação de uma mistura gasosa hipóxica (10% O2 e 90% N2), com isocapnia mantida, durante 3 minutos. Resultados: Os grupos foram semelhantes em relação à etiologia da insuficiência cardíaca 2 pico, índice de massa corpórea e medicações. No basal, não houve diferença entre os grupos quanto ao FSMab e FSMp, condutância vascular do antebraço (CVab) e panturrilha (CVp). Entretanto, a ANSM foi maior no grupo IC+DRS (P<0,05). Durante a hipercapnia, as respostas vasculares (FSMab, CVab, FSMp, CVp) foram significativamente menores no grupo IC+DRS quando comparadas com o grupo IC (P<0,001, para todas as comparações). De forma semelhante, durante a hipóxia, as respostas vasculares (FSMab, CVab, FSMp, CVp) foram significativamente menores no grupo IC+DRS quando comparadas com o grupo IC (P<=0,001, para todas as comparações). A ANSM, em resposta à hipercapnia e à hipóxia, foi maior no grupo IC+DRS. Durante a hipercapnia, as respostas de FC e PAM não foram diferentes entre os grupos. Durante a hipóxia, as respostas de FC não foram diferentes entre os grupos, enquanto a resposta de PAM foi maior nos pacientes do grupo IC+DRS. Não houve diferença na resposta ventilatória entre os grupos estudados. Conclusão: Pacientes com a coexistência de insuficiência cardíaca e distúrbio respiratório do sono apresentam vasoconstrição muscular paradoxal mais exacerbada que pacientes sem o distúrbio respiratório do sono, durante a hipercapnia e a hipóxia, o que parece estar associada, pelo menos em parte, à maior resposta de ANSM
Background: Sleep disordered breathing is common in heart failure patients. Recent studies show that patients with heart failure have paradox muscle vasoconstriction during the central and peripheral chemoreceptors stimulation, which is associated with endothelial dysfunction and exaggerated sympathetic nerve activity. However, whether this vascular response is more pronounced in patients with the coexistence of heart failure and sleep disordered breathing is unknown. Objectives: To test the hypothesis that: 1) The muscle vasoconstriction responses to hypercapnia and hypoxia would be more pronounced in heart failure patients with sleep disordered breathing than in heart failure patients without sleep disordered breathing; 2) This alteration in vascular responses would be associated with endothelial dysfunction and/or exaggerated muscle sympathetic nerve activity (MSNA) responses. Methods: Ninety consecutive heart failure patients, functional class II-III (New York Heart Association), were screened for the study. Forty-one patients who fulfilled all the inclusion criteria were enrolled and allocated into two groups according to apnea-hypopnea index (AHI): HF (AIH < v15 events/hour; n=13, 46 (39-53) years) and HF+SDB (AIH >=15 events/hour; n=28, 57 (54-61) years). Peak oxygen uptake (Peak 2) and left ventricular ejection fraction (LVEF) were evaluated by maximal incremental exercise test and by echocardiography, respectively. Forearm and calf blood flow (FBF and CBF, respectively) were evaluated by venous occlusion plethysmography and MSNA by microneurography technique. Mean blood pressure (MBP) and heart rate (HR) were evaluated by beat-to-beat noninvasive technique (Finometer® PRO). Central chemoreceptors were stimulated by inhalation of a hipercapnic gas mixture (7% CO2 and 93% O2) and peripheral chemoreceptors by inhalation of a hypoxic gas mixture (10% O2 and 90% N2), with maintenance of isocapnia, for 3 minutes each one. Results: Both groups were similar regarding to heart failure etiology, LVEF, Peak 2, body mass index, and medications. At baseline, there were no differences in FBF and CBF, forearm and calf vascular conductance (FVC and CVC, respectively) between groups. However, the MSNA was greater in HF+SDB group (P < 0.05). During hipercapnia, the vascular responses (FBF, FVC, CBF, CVC) were lower in HF+SDB group when compared to HF group (P < 0.001, to all comparisions). Similarly, during hypoxia, the vascular responses (FBF, FVC, CBF, CVC) were lower in HF+SDB group when compared to HF group (P <= 0.001, to all comparisions). The MSNA in response to hypercapnia and hypoxia was greater in HF+SDB group. During hypercapnia, the HR and MBP responses were not different between groups. During hypoxia, the HR responses were similar between groups, while the MBP responses were greater in HF+SDB group. There was no difference in ventilatory response between groups. Conclusion: Patients with the coexistence of heart failure and sleep disordered breathing have more intense muscle vasoconstriction than patients without sleep disordered breathing, during hypercapnia and hypoxia, which seems to be due, at least in part, to increased responsiveness of MSNA

APA, Harvard, Vancouver, ISO, and other styles

Dissertations / Theses on the topic 'Regional flux'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles