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1
Delnord, Marie. « Understanding geographic and temporal variations in preterm birth rates and trends : an international study in 34 high-income countries ». Thesis, Sorbonne Paris Cité, 2017. http://www.theses.fr/2017USPCB059/document.
Texte intégralRésumé :
La prématurité, définie par une naissance avant 37 semaines d’aménorrhées (SA), est une cause majeur de mortalité et de morbidité infantile. Comparés aux enfants nés à terme, les prématurés font face à des risques importants de troubles moteurs et cognitifs durant l'enfance, ainsi que de maladies chroniques et décès prématurés à l’âge adulte. La prématurité constitue un enjeu important de santé publique et en Europe, les taux varient entre 5 et 10%. Notre objectif pour cette thèse était de mieux comprendre les sources d’hétérogénéité des taux à l’échelle des pays. Dans un premier temps, nous avons effectué une revue exhaustive de la littérature qui montre que les caractéristiques maternelles, les pratiques médicales, et les méthodes d'estimation de l'âge gestationnel ont un impact sur les taux de prématurité. Cependant, ces facteurs n'expliquent pas l’ampleur des différences observées entre les pays. Puis, en utilisant des données sur les femmes enceintes, les nouveau-nés et les mort-nés dans 34 pays à revenus élevés de 1996 à 2010, nous avons établi que: 1) les différences d'enregistrement des naissances dans les pays à revenus élevés ont un impact limité sur les taux, sauf pour les naissances à 22-23 SA, 2) les tendances de PTB dans les pays sont associées à des variations plus importantes dans la distribution des âges gestationnels 3) et enfin, en utilisant les données d'un échantillon représentatif des naissances en France en 2010, qu’il existe des facteurs de risques maternels prénatals et socio-démographiques communs aux naissances avant terme (<37SA) et proche du terme à 37-38 SA. Viser à réduire les facteurs de risques de la naissance proche du terme et de la prématurité dans une approche conjointe pourrait apporter un nouvel élan à la prévention de la prématurité. Comparés aux enfants prématurés, les enfants nés proche du terme sont individuellement moins à risque, mais à l’échelle des pays ces enfants représentent environ une naissance sur quatre et ils contribuent de manière importante au fardeau de morbi-mortalité néonatale et infantile. Au niveau national, élargir les efforts de prévention de la prématurité à cette nouvelle population-cible pourrait avoir un plus grand impact sur la santé publiquePreterm birth (PTB), defined as birth before 37 weeks, is a leading cause of infant mortality and morbidity. Compared to term infants, preterm infants face important risks of motor and cognitive impairments throughout childhood, as well as chronic diseases and premature death later in life. PTB represents a significant public health burden and in Europe, rates range between 5 and 10%. Such wide differences suggest that reductions may be possible, but there are few effective interventions, and these tend to target selected groups of high-risk pregnancies, based on clinical risk factors. Our aim for this thesis was to better appraise sources of population-level PTB rate variations and trends. First, we conducted an exhaustive review of the literature and found that maternal characteristics, reproductive policies, medical practices and methods of gestational age (GA) estimation affected PTB rates, but could not explain observed differences across countries. Next, using population-based data on pregnant women, newborns and stillbirths in 34 high-income countries from 1996 to 2010, we showed that: 1) reporting criteria for births and deaths affected PTB rates at early gestations and PTB rankings, but differences between countries with high and low rates are not just due to artefact 2) PTB trends were associated with broader shifts in countries’ gestational age GA distribution of births, and 3) using data from a representative sample of births in France in 2010, that there were shared maternal prenatal and socio-demographic risk factors for deliveries that did not reach full term, at 39 weeks GA. Our work confirms that recording differences in high-income countries have a limited impact on PTB rate variations. However, a broader focus on earlier delivery, including early term birth at 37-38 weeks, could shed light on the determinants of low PTB rates and provide a useful public health prevention paradigm
2
Wang, Xiao-Yu. « Spatial analysis of long-term exposure to air pollution and cardiorespiratory mortality in Brisbane, Australia ». Queensland University of Technology, 2008. http://eprints.qut.edu.au/16627/.
Texte intégralRésumé :
Air pollution is ranked by the World Health Organisation as one of the top ten contributors to the global burden of disease and injury. Epidemiological studies have shown that exposure to air pollution is associated with cardiorespiratory diseases. However, most of the previous studies have looked at this issue using air pollution data from a single monitoring site or average values from a few monitoring sites in a city. There is increasing concern that the relationships between air pollution and mortality may vary with geographical area, particularly for a big city. This thesis consisted of three interlinked studies that aimed to examine the spatial variation in the relationship between long-term exposure to air pollution and cardiorespiratory mortality in Brisbane, Australia. The first study evaluated the long-term air pollution trends in Brisbane, Australia. Air pollution data used in this study were provided by the Queensland Environmental Protection Agency (QEPA). The data comprised the daily average concentrations of particulate matter less then 10 µm in aerodynamic diameter (PM10), nitrogen dioxide (NO2), ozone (O3) and sulphur dioxide (SO2) between 1 January 1980 and 31 December 2004 in two monitoring sites (i.e. Eagle farm and Rocklea), and in other available monitoring sites between 1 January 1996 and 31 December 2004. Computerised data files of daily mortality between 1 January 1996 and 31 December 2004 in Brisbane city were provided by the Office of Economic and Statistical Research of the Queensland Treasury. Population data and the Socio-Economic Indexes for Areas (SEIFA) data in 2001 were obtained from the Australian Bureau of Statistics (ABS) for each statistical local area (SLA) of the Brisbane city. The long-term air pollution (the daily maximum 1-hour average or daily 24-hour average concentrations of NO2, O3 and PM10) trends were evaluated using a polynomial regression model in two monitoring sites (Eagle Farm and Rocklea) in Brisbane, Australia, between 1980 and 2003. The study found that there were significant up-and-down features for air pollution concentrations in both monitoring sites in Brisbane. Rocklea recorded a substantially higher number of days with concentrations above the relevant daily maximum 1-hour or 24-hour standards than that in Eagle Farm. Additionally, there was a significant spatial variation in air pollution concentrations between these areas. Therefore, the results indicated a need to examine the spatial variation in the relationship between long-term exposure to air pollution and cardiorespiratory mortality in Brisbane. The second study examined the spatial variation of SO2 concentrations and cardiorespiratory mortality in Brisbane between 1999 and 2001. Air pollutant concentrations were estimated using geographical information systems (GIS) techniques at a SLA level. Spatial distribution analysis and a multivariable logistic regression model were employed to investigate the impact of gaseous air pollution on cardiorespiratory mortality after adjusting for potential confounding effects of age, sex, calendar year and SEIFA. The results of this study indicate that for every 1 ppb increase in annual average SO2 concentration, there was an estimated increase of 4.4 % (95 % confidence interval (CI): 1.4 - 7.6 %) and 4.8 % (95 % CI: 2.0 - 7.7 %) in cardiovascular and cardiorespiratory mortality, respectively. We estimated that the excess number of cardiorespiratory deaths attributable to SO2 was 312 (3.4% of total cardiorespiratory deaths) in Brisbane during the study period. Our results suggest that long-term exposure to SO2, even at low levels, is a significant hazard to population health. The final study examined the association of long-term exposure to gaseous air pollution (including NO2, O3 and SO2) with cardiorespiratory mortality in Brisbane, Australia, 1996 - 2004. The pollutant concentrations were estimated using GIS techniques at a SLA level. Logistic regression was used to investigate the impact of NO2, O3 and SO2 on cardiorespiratory mortality after adjusting for potential confounding effects of age, sex, calendar year and SEIFA. The study found that there was an estimated 3.1% (95% CI: 0.4 - 5.8%) and 0.5% (95% CI: -0.03 - 1.3 %) increase in cardiorespiratory mortality for 1 ppb increment in annual average concentration of SO2 and O3, respectively. However there was no significant relationship between NO2 and cardiorespiratory mortality observed in the multiple gaseous pollutants model. The results also indicated that long-term exposure to gaseous air pollutants in Brisbane, even at the levels lower than most cities in the world (especially SO2), were associated with cardiorespiratory mortality. Therefore, spatial patterns of gaseous air pollutants and their impact on health outcomes need to be assessed for an evaluation of long-term effects of air pollution on population health in metropolitan areas. This study examined the relationship between air pollution and health outcomes. GIS and relevant mapping technologies were used to display the spatial patterns of air pollution and cardiorespiratory mortality at a SLA level. The results of this study show that long-term exposure to gaseous air pollution was associated with cardiorespiratory mortality in Brisbane and this association appeared to vary with geographic area. These findings may have important public health implications in the control and prevention of air pollution-related health effects, since now many countries and governments have paid more attention to control wide spread air pollution and to protect our environment and human health.
3
Wang, Xiao Yu. « Spatial analysis of long-term exposure to air pollution and cardiorespiratory mortality in Brisbane, Australia ». Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/16627/1/Xiao-Yu_Wang_Thesis.pdf.
Texte intégralRésumé :
Air pollution is ranked by the World Health Organisation as one of the top ten contributors to the global burden of disease and injury. Epidemiological studies have shown that exposure to air pollution is associated with cardiorespiratory diseases. However, most of the previous studies have looked at this issue using air pollution data from a single monitoring site or average values from a few monitoring sites in a city. There is increasing concern that the relationships between air pollution and mortality may vary with geographical area, particularly for a big city. This thesis consisted of three interlinked studies that aimed to examine the spatial variation in the relationship between long-term exposure to air pollution and cardiorespiratory mortality in Brisbane, Australia.
The first study evaluated the long-term air pollution trends in Brisbane, Australia. Air pollution data used in this study were provided by the Queensland Environmental Protection Agency (QEPA). The data comprised the daily average concentrations of particulate matter less then 10 µm in aerodynamic diameter (PM10), nitrogen dioxide (NO2), ozone (O3) and sulphur dioxide (SO2) between 1 January 1980 and 31 December 2004 in two monitoring sites (i.e. Eagle farm and Rocklea), and in other available monitoring sites between 1 January 1996 and 31 December 2004. Computerised data files of daily mortality between 1 January 1996 and 31 December 2004 in Brisbane city were provided by the Office of Economic and Statistical Research of the Queensland Treasury. Population data and the Socio-Economic Indexes for Areas (SEIFA) data in 2001 were obtained from the Australian Bureau of Statistics (ABS) for each statistical local area (SLA) of the Brisbane city.
The long-term air pollution (the daily maximum 1-hour average or daily 24-hour average concentrations of NO2, O3 and PM10) trends were evaluated using a polynomial regression model in two monitoring sites (Eagle Farm and Rocklea) in Brisbane, Australia, between 1980 and 2003. The study found that there were significant up-and-down features for air pollution concentrations in both monitoring sites in Brisbane. Rocklea recorded a substantially higher number of days with concentrations above the relevant daily maximum 1-hour or 24-hour standards than that in Eagle Farm. Additionally, there was a significant spatial variation in air pollution concentrations between these areas. Therefore, the results indicated a need to examine the spatial variation in the relationship between long-term exposure to air pollution and cardiorespiratory mortality in Brisbane.
The second study examined the spatial variation of SO2 concentrations and cardiorespiratory mortality in Brisbane between 1999 and 2001. Air pollutant concentrations were estimated using geographical information systems (GIS) techniques at a SLA level. Spatial distribution analysis and a multivariable logistic regression model were employed to investigate the impact of gaseous air pollution on cardiorespiratory mortality after adjusting for potential confounding effects of age, sex, calendar year and SEIFA. The results of this study indicate that for every 1 ppb increase in annual average SO2 concentration, there was an estimated increase of 4.4 % (95 % confidence interval (CI): 1.4 - 7.6 %) and 4.8 % (95 % CI: 2.0 - 7.7 %) in cardiovascular and cardiorespiratory mortality, respectively. We estimated that the excess number of cardiorespiratory deaths attributable to SO2 was 312 (3.4% of total cardiorespiratory deaths) in Brisbane during the study period. Our results suggest that long-term exposure to SO2, even at low levels, is a significant hazard to population health.
The final study examined the association of long-term exposure to gaseous air pollution (including NO2, O3 and SO2) with cardiorespiratory mortality in Brisbane, Australia, 1996 - 2004. The pollutant concentrations were estimated using GIS techniques at a SLA level. Logistic regression was used to investigate the impact of NO2, O3 and SO2 on cardiorespiratory mortality after adjusting for potential confounding effects of age, sex, calendar year and SEIFA. The study found that there was an estimated 3.1% (95% CI: 0.4 - 5.8%) and 0.5% (95% CI: -0.03 - 1.3 %) increase in cardiorespiratory mortality for 1 ppb increment in annual average concentration of SO2 and O3, respectively. However there was no significant relationship between NO2 and cardiorespiratory mortality observed in the multiple gaseous pollutants model. The results also indicated that long-term exposure to gaseous air pollutants in Brisbane, even at the levels lower than most cities in the world (especially SO2), were associated with cardiorespiratory mortality.
Therefore, spatial patterns of gaseous air pollutants and their impact on health outcomes need to be assessed for an evaluation of long-term effects of air pollution on population health in metropolitan areas.
This study examined the relationship between air pollution and health outcomes. GIS and relevant mapping technologies were used to display the spatial patterns of air pollution and cardiorespiratory mortality at a SLA level. The results of this study show that long-term exposure to gaseous air pollution was associated with cardiorespiratory mortality in Brisbane and this association appeared to vary with geographic area. These findings may have important public health implications in the control and prevention of air pollution-related health effects, since now many countries and governments have paid more attention to control wide spread air pollution and to protect our environment and human health.
4
Gonçalves, Daniel Ruiz Potma. « Soil carbon balance in long-term no-till in a sub-tropical environment ». Universidade Estadual de Ponta Grossa, 2018. http://tede2.uepg.br/jspui/handle/prefix/2525.
Texte intégralRésumé :
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Solos podem ser uma fonte ou um dreno de CO2 atmosférico, dependendo do seu sistema de manejo. Atualmente, o uso do solo e mudança de uso do solo emitem 1,3 ± 0,5 Pg C ano-1, equivalente a 8% das emissões globais. Técnicas como a agricultura de baixa emissão de C têm sido desenvolvidas para sequestrar C nos solos e reduzir a emissão de gases do efeito estufa. Porém, além dos desafios políticos e sociais envolvendo a doção destes sistemas, ainda há muita incerteza sobre o seu real potencial de mitigação. Assim, os objetivos desse estudo foram: i) Quantificar as fontes históricas e atuais de emissão de gases do efeito estufa na região dos Campos Gerais do Paraná, Brasil; ii) quantificar o potencial das melhores práticas de manejo agrícola baseadas nos três pilares da agricultura de conservação: Solo permanentemente coberto, plantio direto e rotação de culturas, em longo prazo (30 anos) para sequestrar carbono no solo, utilizando a fazenda Paiquerê (localizada na região dos Campos Gerais) como um modelo de sucesso; iii) estimar o impacto da adoção das melhores práticas de manejo nas áreas agrícolas da região e globalmente onde adequadas pelos próximos 100 anos utilizando os modelos Century e Roth-C. As fontes de gases do efeito estufa foram apresentadas como um inventário e mostraram que as emissões históricas (1930 – 2017) foram 412,18 Tg C, no qual as mudanças de uso do solo contribuíram com 91% (376,2±130 Tg C). As florestas sequestraram 51.7 ± 23.9 Tg C em 0.6 Mha em 47 anos (1.8 Tg C Mha-1 ano-1) e o plantio direto sequestrou 30.4 ± 23.9 Tg C em 1.9 Mha em 32 anos (0.5 Tg C Mha-1 ano-1). Ambos os modelos tiveram uma boa performance e o modelo Century foi mais eficiente em simular os estoques de carbono do solo, o resíduo médio da simulação foi 10 Mg C ha−1 (13%) para n = 91. O resíduo do modelo aumentou com a quantidade de óxidos no solo, sugerindo que a inclusão do controle mineralógico pode reduzir o viés de simulação. As predições do Century mostraram que o sistema tem potencial para mitigar 13 anos de emissões regionais (330 Tg C em 100 anos) ou 105 anos de emissões do setor agricultura, floresta e pecuária (40 Tg em 100 anos) na região. Da mesma forma, globalmente o sistema apresenta um potencial para sequestrar 2,5 ± 0.02 Pg C na profundidade 0–20 cm e 11,7 ± 3 Pg C na profundidade 0-100 cm em 86 milhões de ha distribuídos por todo o mundo. Este valor é equivalente à 11% das emissões globais dos setores agricultura, floresta e pecuária e mudanças de uso do solo. Assim, a nossa metodologia possa ser utilizada como um modelo para divulgar o potencial da agricultura conservacionista em sequestrar C nos solos e suportar políticas públicas que visem à mitigação das emissões de gases do efeito estufa.
Soils can be a source or sink of atmospheric CO2, according to land use and management. Currently the land use and land use change (LULUC) emits 1.3 ± 0.5 Pg carbon (C) year-1, equivalent to 8% of the global annual emission. Techniques such as low carbon agriculture, has been developed to sequester C in soils and reduce greenhouse gas (GHG) emissions. However, besides political and social challenges for the system adoption, there’s still great uncertainty related to its real mitigation potential. This study aimed: i) Quantify the historical and current main sources of GHG emissions for Campos Gerais region in Paraná state, Brazil; ii) quantify the potential of long term (30 years) agricultural best management practices, based on the three pillars of conservative agriculture: permanent soil cover, crop rotation and no-till, to sequester C in soils, using Paiquerê farm (located in Campos Gerais region) as a successful model; iii) estimate the impact of best management practices adoption in the region croplands and globally for the next 100 years where is suitable using Century and Roth-C models. The GHG emission sources were presented as an inventory and showed that historical (1930 – 2017) GHG emissions in the region was 412.18 Tg C, in which LULUC contributes 91% (376.2±130 Tg C). Forestry sequestered 51.7 ± 23.9 Tg C in 0.6 Mha in 47 years (1.8 Tg C Mha-1 year-1) and no-till sequestered 30.4 ± 23.9 Tg C in 1.9 Mha in 32 years (0.5 Tg C Mha-1 year-1). Both models performed well, and Century was more efficient for simulate the SOC stocks, the mean residue was 10 Mg C ha−1 (13%) for n = 91. The model residue increased along with the oxides content in the soil clay fraction, suggesting that mineralogical control inclusion can reduce the model simulation bias. Century predictions showed that the system currently practiced at Paiquerê farm have the potential to mitigate 13 years of regional total emissions (330 Tg C in 100 years) or 105 years of agriculture, forestry and other land use (AFOLU) sector emissions (40 Tg in 100 years) in the region. In the same way, it has the potential to sequester 2.5±0.02 Pg C at 0-20 cm and 11.7±3 Pg C at 0-100 cm soil depth in 86 million ha globally. This is equivalent to 11% of global annual emissions from LULUC sector. In this way, our methodology can be used as a model to access the potential of conservation agriculture to sequester C and support public policies aiming to mitigate GHG emissions.
5
Hunnicutt, Jacob N. « Opioid Use and Safety in United States Nursing Homes ». eScholarship@UMMS, 2018. https://escholarship.umassmed.edu/gsbs_diss/975.
Texte intégralRésumé :
Background: Opioids are often used in nursing homes to manage non-malignant pain, but little is known about their long-term use, initiation, and comparative safety.
Methods: We used the Minimum Data Set 3.0 from 2011-2013 merged to Medicare and facility characteristics data to study opioid use and safety among older, long-stay residents. The specific aims were to examine the 1) prevalence of long-term opioid use; 2) geographic variation in the initiation of commonly used opioids (oxycodone, hydrocodone, tramadol); and 3) comparative safety of commonly used opioids and fracture hospitalizations.
Results: One in seven long-stay residents were prescribed opioids long-term. There was extensive geographic variation in the initiation of commonly used opioids, with oxycodone (9.4%) initiated less frequently than hydrocodone (56.2%) or tramadol (34.5%) but varying most extensively across the United States, with the majority of variation in prescribing explained by state of residence. Compared to hydrocodone initiators (7.9 fracture hospitalizations per 100-person years), those initiating tramadol had lower rates of fracture hospitalizations (subdistribution hazard ratio [HRSD] = 0.67, 95% Confidence Interval [CI]: 0.56-0.80), whereas oxycodone initiators had similar rates of fracture hospitalizations (HRSD=1.08, 95% CI: 0.79-1.48).
Conclusion: The prevalence of long-term opioid use was twice as common in nursing homes as community settings, with initiation patterns varying extensively by region and being strongly driven by state of residence. Although initiating tramadol was associated with lower rates of fractures than hydrocodone, questions on opioid risks and benefits remain and are especially pertinent given the high mortality rates in this population.
6
Mack, Deborah Sara. « Statin Pharmacotherapy in U.S. Nursing Homes ». eScholarship@UMMS, 2020. https://escholarship.umassmed.edu/gsbs_diss/1104.
Texte intégralRésumé :
Background: Statins have questionable benefits among older adults with life-limiting illness. Statin use is widespread among U.S. older adults, but little is known about use in nursing homes. This dissertation was designed to identify the prevalence and predictors of statin pharmacotherapy use and discontinuation in U.S. nursing homes.
Methods: Data sources (2011-2016) included: Minimum Data Set 3.0, Medicare administrative claims data, Provider of Service files, and Dartmouth Atlas files. Analyses included: descriptive statistics, multilevel modeling, and proportional change in cluster variations with adjustments to reduce confounding and model misspecification.
Results: Approximately 36% of older adults admitted to U.S. nursing homes between 2015 – 2016 were actively using statins at the time of admission. Among long-stay residents with life-limiting illness, 34% were on statins at one time (2016; aged 65-75 years: 44%, >75 years: 31%). Statin use varied significantly by hospital referral regions, with most variation in the >75 age group. Limiting the sample to statin users, 20% discontinued statins within 30 days of nursing home admission. While discontinuation was positively associated with severity of life-limiting condition, the majority of residents remained on statins 30 days post-admission, including those with a < 6-month prognosis.
Conclusion: Statin use is pervasive across US nursing homes and persists with life-limiting illness. Geographic variation appeared to coincide with clinical uncertainty, especially among adults >75 with few national guidelines. More needs to be done to prioritize statin deprescribing in nursing homes with research that identifies ways to facilitate improved patient-provider awareness and engagement in the discontinuation process.
7
Toumi, Narjess. « Essays on the performance of initial public offerings ». Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC0005.
Texte intégralRésumé :
Cette thèse est composée de trois essais qui étudient le déroulement des introductions en bourse. Dans le premier essai, nous examinons l’effet de la séparation propriété-contrôle sur la performance des offres publiques initiales (IPO) à long terme en France. En utilisant un échantillon de 351 entreprises françaises introduites en bourse sur la période 1997-2011, nous constatons que la séparation entre les droits de vote et les droits de propriété des actionnaires majoritaires est négativement associée à la performance à long terme des introductions en bourse. Cette constatation indique que les IPO ayant une structure de propriété dispersée sont moins performantes que les autres entreprises au cours de la période allant de 1 à 5 ans suivant l'offre initiale. Cette séparation incite les actionnaires dominants à retirer des avantages privés de contrôle au détriment des actionnaires minoritaires.Dans le deuxième essai, nous examinons le rôle des clauses de lock-up sur la précision des prévisions de résultat publiées dans le prospectus d'introduction en bourse. En utilisant un échantillon de 303 prévisions des entreprises françaises introduites en bourse entre 1997 et 2013, nous apportons la preuve que les introductions en bourse ayant plus d'actions à détenir, ainsi que celles qui choisissent des périodes de lock-up plus longues, sont plus susceptibles de divulguer des prévisions de résultats conservatrices et précises. Ces résultats sont robustes à un certain nombre de tests de sensibilité.Dans le troisième essai, nous étudions l'impact de la localisation géographique sur la sous-évaluation à court terme des introductions en bourse françaises. Les résultats montrent que les entreprises situées à proximité du centre financier parisien sont moins sous-estimées que les entreprises distantes. Ces résultats fournissent un support empirique à l'argument selon lequel l'incertitude sur la valeur des IPO augmente proportionnellement à la distance de Paris. En d'autres termes, la proximité géographique améliore la qualité des informations collectées sur les entreprises, ce qui réduit leurs coûts d'introduction en bourse et diminue le niveau des rendements initiauxThis dissertation consists of three essays. In the first essay, we investigate whether the control-ownership divergence can explain IPO long-run performance in France. Using data from a sample of 351 French IPOs during 1997-2011, we find that the separation between ownership and control rights of the largest shareholder is negatively associated with long-term performance of French IPOs. This finding indicates that IPOs with disproportional ownership structure underperform other firms in the one- to five-year period following the initial offering. Such separation induces controlling shareholders to extract private benefits of control to the detriment of minority shareholders.In the second essay, we examine the effect of lockup agreements on management earnings forecasts in initial public offering (IPO) prospectuses. Using a sample of 303 forecasts of French firms that went public over the period 1997–2013, we find that IPOs with lockup clauses are more likely to disclose conservative profit forecasts. Moreover, we provide evidence that IPOs with more shares to lock up, as well as those selecting longer lockup periods, have more accurate management earnings forecasts. These results are robust to a number of sensitivity tests.In the third essay, we examine the impact of geographic location on the short–run underpricing of French initial public offerings (IPOs). The results show that firms located in close proximity to the financial centre, Paris, are less underpriced than distant ones. These findings provide empirical support to the argument that uncertainty about IPO value increases with distance from Paris. In other words, geographic proximity improves the quality of collected information on IPO firms, which lowers their costs of going public and decreases the level of initial returns
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Lanzara, Gianandrea <1986>. « Essays in Economic Geography and Long-Term Development ». Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9528/1/thesis_final.pdf.
Texte intégralRésumé :
This dissertation has two main themes: first, the economic impact of tourism on cities and, secondly, the
determinants of European long-run development, with a focus on the pre-Industrial era. The common thread
is the attempt to develop economic geography models that incorporate spatial frictions and are liable to be
given empirical content. Chapter 1, written in conjunction with G. Alfredo Minerva, provides an empirical
analysis of the relationship between tourism and economic activity across Italian municipalities, and lays
down the basic elements of an urban theory of tourism in an a-spatial setting. Chapter 2 extends these ideas
to a quantitative urban framework to study the economic impact and the welfare consequences of tourism
into the city of Venice. The model is given empirical content thanks to a large collection of data at the
Census tract level for the Municipality of Venice, and then used to perform counterfactual policty analysis.
In chapter 3, with Matteo Santacesaria, we consider a setting where agents are continuously distributed
over a two-dimensional heterogeneous geography, and are allowed to do business at a finite set of markets.
We study the equilibrium partition of the economic space into a collection of mutually-exclusive market
areas, and provide condition for this equilibrium partition to exist and to be unique. Finally, chapter 4
"The rise of (urban) Europe: a Quantitative-Spatial analysis", co-authored with Matteo Cervellati and
Alex Lehner, sets up a quantitative economic geography model to understand the roots of the Industrial
Revolution, in an attempt to match the evolution of the European urban network, and the corresponding
city-size distribution, over the period A.D. 1000-1850. It highlights the importance of agricultural trade
across cities for the emergence of large manufacturing hubs.
9
Chubachi, Natsuko. « Geographies of nisei Japanese Canadians and their attitudes towards elderly long-term care ». Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0001/MQ42599.pdf.
Texte intégral
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Barnett, Sarah Anne Louise. « An application of multilevel modelling techniques to the study of geographical variations in health outcome measures ». Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327258.
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Ullestad, Mollie. « University Student Indigenous Intercultural Sensitivity and Short-term Study Abroad ». Thesis, University of Missouri - Columbia, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=13850756.
Texte intégralRésumé :
There is an extreme underrepresentation of indigenous peoples within American study abroad programs, and student participants rarely gain an authentic experience, awareness, and intercultural sensitivity towards such groups. This case study seeks to address this disparity through the creation of a new geography short-term study abroad program titled, “Resources and Indigenous Peoples of Oceania”, at the University of Missouri. This program is based on providing geographic opportunities for students to experience the diverse physical landscapes of New Zealand and interact with the local Maori indigenous people and their culture. The Developmental Model of Intercultural Sensitivity (DMIS) is used both before and after the study abroad program to measure changes in student participants’ indigenous intercultural sensitivity, as well as student program journal entries and final papers. The goal of this case study is to discover whether or not a study abroad program with a focus on elements of indigenous culture can actually improve students’ intercultural sensitivity towards such groups.
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Suggs, Jessica Marie. « Long-term Changes in Synoptic-Scale Air Mass Persistence Across the United States ». Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/78705.
Texte intégralRésumé :
From a climate dynamics perspective, air mass persistence reflects variability in the dynamic nature of the atmosphere. In this study, a historical analysis of synoptic air mass persistence across the continental United States is presented to portray spatial and temporal variability and trends in air mass residence times. Historical daily air mass calendars for 140 locations across the United States for the 60-year period 1955 through 2015 were extracted from the Spatial Synoptic Classification database. The data were stratified by season, and a historical climatology of seasonal air mass occurrence was created for each location. The historical daily air mass data were then translated into a record of residence time, or the length of consecutive days that a synoptic air mass type was in place at a location. Each historical record of seasonal air mass residence times, or persistence, was then analyzed for spatial variability across the United States and for temporal variability and trends. Results reveal a statistically significant increase in air mass persistence for many areas of the country during three seasons, but most commonly across the southern United States during the summer season (June-August). However, this pattern was reversed for the winter season (December-February), the analyses revealed a general pattern of decreasing cool-season air mass persistence across the continental United States. The seasonally-dependent change in air mass persistence across the United States may be indicative of changed or changing mid-latitude atmospheric dynamics in the form of a previously suggested northward migration of the polar jet stream.Master of Science
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Amini, Shima. « The Effect of Geography on Small British IPOs ; Activity, Fitiancial Characteristics, Long-term I'ertormance and Survival ». Thesis, University of Leeds, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534422.
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Obarein, Omon A. « Relative Long-term Changes in West African Rainfall Components ». Kent State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=kent1598884754345658.
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Pinfold, Vanessa Anne. « Community connections : geographies of rehabilitation amongst people with long term and enduring mental health problems in Nottingham ». Thesis, University of Nottingham, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324061.
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Coultish, Tara L. « Long-term development of palsas and other permafrost-cored mounds in mountainous terrain, Wolf Creek, southern Yukon ». Thesis, University of Ottawa (Canada), 2002. http://hdl.handle.net/10393/6454.
Texte intégralRésumé :
Fifty-one frost mounds were examined in Wolf Creek, Yukon Territory (60°30'N, 135°13'W) at an elevation of 1235 m a.s.l. Cryostratigraphic analyses and aerial photographic interpretation were undertaken to investigate the origin and longevity of the mounds, and to assess their utility as climatic indicators. It was determined that 37 mounds were palsas, as evidenced by their dimensions, cryostructure of segregated ice and location within a fen; one mound was a frost blister, as evidenced by its core of intrusive ice; one mound may have been a compound form, with segregation and possibly intrusive ice; and 12 mounds were termed aggradational permafrost mounds as their cores were of segregated ice but they did not fit the locational requirements to be palsas. Aerial photographs, spanning the period from 1946 to 2001, showed that palsas at the study site have been aggrading and degrading continually over the past 55 years, and are continuing to do so. (Abstract shortened by UMI.)
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Seymour, Chelsea R. « Natives Versus Exotics and Grasses Versus Forbs| A Long-Term Study of Vegetation in La Jolla Valley ». Thesis, California State University, Long Beach, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10604415.
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California grasslands are well known for the exotic species invasions they have undergone and the resulting decrease in native flora. Issues with restoring these lands lie in determining the pre-invasion vegetation composition and the mechanisms of invasion. This study compares data from three surveys of a set of permanent quadrats in La Jolla Valley in order to determine changes over time. Each iteration included data on vegetation cover, frequency, and shrub density. It was found that native grass cover has decreased, and exotic grass cover has fluctuated widely. Also, both native and exotic forb cover increased greatly. This supports Minnich’s forb-field theory over Clements’ bunchgrass theory. The natural enemies and disturbance hypotheses did not accurately predict these results. When the quadrats were divided in valley floor and valley edge categories the post-disturbance hypothesis accurately predicted the result that edge quadrats have greater native grass cover than their floor counterparts.
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Lai, Ling-yan Edith. « Effects of cooperative learning on student learning outcomes and approaches to learning in sixth form geography ». Click to view the E-thesis via HKUTO, 1991. http://sunzi.lib.hku.hk/HKUTO/record/B38627292.
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Gregory, Ian N. « A historical GIS for England and Wales : a framework for reconstructing past geographies and analysing long-term change ». Thesis, Queen Mary, University of London, 2001. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1526.
Texte intégralRésumé :
This thesis describes the creation and possible uses of a Geographical Information System that contains the changing boundaries of the major administrative units of England and Wales from 1840 to 1974. For over 150 years the census, the General Register Office, and others have used these units to publish a wealth of data concerning the population of the country. The key issue addressed by the thesis is that changes in the administrative geography have hampered much research on long-term change in society that could have been done using these sources. The goal of the thesis is the creation of framework to allow the analysis of long-term socio-economic change that makes maximum use of the available data. This involves not only making use of the data's attribute (statistical) component, but also their spatial and temporal components. In order to do this, the thesis provides solutions to two key problems: the first is how to build a GIS containing administrative units that incorporates an accurate record of their changing boundaries and can be linked to statistical data in a flexible manner. The second is how to remove the impact of boundary changes when comparing datasets published at different dates. This is done by devising a methodology for interpolating data from the administrative units they were published using, onto a single target geography. An evaluation of the accuracy of this interpolation is performed and examples are given of how this type of research could be conducted. Taken together, these will release information locked up within historical socio-economic statistics by allowing space to be explicitly incorporated into any explorations of the data. This, in turn, allows research to explore the past with increased levels of both spatial and attribute data for longer time periods.
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Zhou, Zhiwei. « The applications of InSAR time series analysis for monitoring long-term surface change in peatlands ». Thesis, University of Glasgow, 2013. http://theses.gla.ac.uk/4875/.
Texte intégralRésumé :
In the past three decades, peatlands all over the world such as upland bogs, tropical fens, have been undergoing significant and rapid degradations. These degradations cause carbon loss and CO2 emissions, and also fuel climate change. In this research, I present three case studies on how space geodetic tools, especially Radar Interferometry (InSAR), can be used to monitor and to advance our understanding of the long-term surface changes in peatlands. First, I investigate the eroding extent and severity of upland UK peatlands using InSAR. Both short wavelength C-band and long wavelength L-band data are explored in this study. I detect a long-term peat subsidence rate of about 0.3 cm/yr, and 2 cm of decrease in peat height between 2002 and 2010. I also examine the coherence performance of C- and L-band over upland bogs. I find L-band data provides better coherence than C-band in upland bogs. Second, I use InSAR time series generated by L-band images to map the spatial and temporal subsidence of drained tropical peatlands in Sumatra, Indonesia. And based on InSAR-derived subsidence rate data, I estimate carbon loss or CO2 emission. Third, I assess the effectiveness of peatland restoration work in in Central Kalimantan, Indonesia using InSAR (L-band images). Restoration effects and impact factors are investigated by the spatial and temporal changes of peat height, which also provide useful information for guiding future restoration activities in this region. Overall, this research suggests that InSAR time series is feasible to monitor long-term peat height change in peatlands, provides new insights into the dynamic surface changes in peatlands, and helps to study the carbon loss and CO2 emissions from peatlands, and understand restoration effects.
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Meadows, Tim. « Forecasting long-term sediment yield from the upper North Fork Toutle River, Mount St. Helens, USA ». Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/27800/.
Texte intégralRésumé :
The Toutle-Cowlitz River system experienced dramatic landscape disturbance during the catastrophic eruption of Mount St Helens on May 18, 1980. The eruption was triggered by a 2.5 km3 debris avalanche which buried the upper 60 km2 of the North Fork Toutle River catchment to an average depth of 45 m and obliterated the surface drainage network. Subsequent channel response on the debris avalanche, dominated by incision and widening, has delivered significant quantities of sediment to downstream reaches where resultant deposition has reduced channel capacity and heightened flood risk. Estimates of future sediment yield from the upper North Fork Toutle River are therefore required to inform development of sustainable options for long-term flood risk mitigation. Previous estimates have been based on extrapolation of post-eruption trends in sediment yield and channel network evolution, but the divergent predictions reported in a number of studies have clouded effective decision-making regarding long-term sediment management. This study therefore uses a numerical, landscape evolution model (CAESAR-Lisflood) to make long-term forecasts of sediment yield based on process simulation rather than extrapolation. A suite of forecasts of cumulative catchment sediment yields up to 2100 are produced using scenario-based model runs designed to account for uncertainty associated with the hydrological impacts of climate change and the model coefficient for lateral mobility. The forecasts fall in a narrow band +/-20% of the mean that lies between two previous estimates derived from the extrapolation of post-eruption trends. Importantly, predicted trends in future annual sediment yield are predominantly linear, although some limited decay is evident for runs in which modelled channel lateral mobility is lower. Sustained sediment production in the upper North Fork Toutle River is found to result from persistent bank erosion and channel widening. These findings cast doubt on the applicability of negative exponential decay functions based on the rate law to characterise post-disturbance sediment yield when lateral rather than vertical adjustments dominate channel evolution. Moreover, forecast trends in future sediment yield suggest that it may not be possible to manage future sediment-related flood risk along the lower Cowlitz solely by retaining sediment in the upper North Fork Toutle River catchment.
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Mount, Nicholas James. « Medium-term response of lowland river reaches to changes in upland land use ». Thesis, Liverpool John Moores University, 2000. http://researchonline.ljmu.ac.uk/5598/.
Texte intégralRésumé :
The afforestation of upland areas in the UK has been the largest rural land use change this century. As a consequence of afforestation the bed load yields of upland catchments have been shown to increase substantially. The upland catchment bed load is transported downstream, through the transfer zone to the lowland reaches where it may enter storage in barforms, cause flow diversion and cause channel instability. This study investigates the Afon Trannon, a river in mid-Wales whose upland catchment was afforested between 1948 and 1978 and whose lowland channel is currently unstable. Historical rates of channel change in the lowland channel have been quantified using aerial photogrammetry in ERDAS Imagine GIS. Channel instability is shown to increase significantly between 1963 and 1976, some 15 years after upland catchment afforestation. However, upland catchment bed load yields are shown to be of low magnitude (up to an estimated maximum of6.35 t km-2 yr") and incapable of producing the high medium-term lowland channel change rates observed (up to 1.88 m yr" between 1963 and 1976). Contemporary channel DTMs constructed from field survey data have allowed the construction of a contemporary lowland channel sediment budget. Local inputs of bed load from composite bank erosion are shown to dominate in the budget and reaches of maximum instability are shown to correspond with the location of these composite banks. Additionally. flood magnitude and frequency are shown to have increased since 1988 from a maximum stage of 1.50 m between 1969 and 1988 to a maximum stage of2.23 m between 1989 and 2000. A conceptual model is presented in which the medium-term instability of the lowland Afon Trannon is suggested to be triggered by local lowland bed aggradation as a result of elevated upland catchment bed load yields and a risk assessment diagram provides advice to river engineers and fluvial geomorphologists interested in assessing the potential stability of lowland rivers whose upland catchments have been afforested.
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Todd, Beverley. « Reconstructing long-term records of UK drought and analysis of variability, 1697-2013 ». Thesis, University of Liverpool, 2014. http://livrepository.liverpool.ac.uk/2011366/.
Texte intégralRésumé :
Droughts are one of the most widespread and complex natural hazards, and remain poorly understood in the context of the United Kingdom. Although the UK is perceived as a relatively water rich country, droughts are a recurrent feature of its climate, causing widespread and serious environmental and economic impacts. Current understanding of drought risk is often based on relatively short records, and/or a small number of specific contemporary case study events from the last couple of decades (e.g. 1976). This study addresses this problem through the development of long (>150 year) meteorological drought records reconstructed using the self-calibrating Palmer Drought Severity Index (scPDSI). The index was calculated using long duration temperature and rainfall records. New rainfall series were generated for Carlisle and Chatsworth, existent rainfall series were extended for Kew, Spalding, Manchester, Edinburgh and Oxford. Additional rainfall series were kindly provided for Appleby and Durham. Temperature series for the Lancashire Plain, Oxford, Edinburgh and Durham were also extended. Where appropriate the newly developed and existing series were evaluated and tested to ensure homogeneity. The drought reconstructions identify multiple drought-rich periods, particularly in the eighteenth and twentieth centuries, with an increasing tendency towards more severe droughts during the latter period. Prolonged rainfall deficiencies are found to be the primary cause of severe droughts, with rising temperatures exacerbating the rainfall conditioned drought pattern. Cycles at the 6-10 year period identify a sub-decadal to decadal signal during the more drought-rich periods, which can be interpreted as reflecting large scale modes of climate variability. Analysis of the spatial variability of droughts finds that whilst severe events predominantly display spatial coherence, there are notable variations in drought characteristics (severity and duration) that reflect intra- and interregional variability in drought behaviour. In part this can be attributed to localised variations in rainfall and distance between sites. This study extends the temporal range of previous drought studies and places recent drought events in a longer context, improving upon existing ‘benchmark’ drought analyses; with far-reaching implications for local, national and continental scale reduction of drought vulnerability and risk.
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Brennan, Sean G. « The long term dynamics of coyote brush invasion in a type-converted landscape of Southern California ». Thesis, California State University, Long Beach, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=1596454.
Texte intégralRésumé :
Coyote brush (Baccharis pilularis) is a native shrub common to the coastal sage scrub (CSS) habitat of California and often appears in a complex mosaic with other vegetation types including grasslands. Both CSS and California grasslands are threatened habitats, where restorations of type-converted landscapes are often burdened by the persistent dominance of non-native annual grasses. However, coyote brush has been documented periodically invading grasslands, resulting in a change of state from grassland to shrubland. This study investigates the long-term dynamics of coyote brush invasion in a type-converted landscape of Southern California. Stands of expanding coyote brush were transected to identify species composition along a spatial and temporal continuum. Results show that following initial invasion, non-native species are replaced by not only coyote brush, but also several other noteworthy native species. This study shows that in Southern California, coyote brush invasion of type-converted landscapes leads to increased native diversity that includes native grasses.
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Talbot, Julie. « Drainage as a model for long-term climate change effect on vegetation dynamics and carbon cycling in boreal peatlands ». Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=86807.
Texte intégralRésumé :
Peatlands are important components of the global carbon cycle, storing one-third of the global soil carbon. The accumulation of peat depends on two main interacting factors: the wetness and vegetation composition of a peatland. Previous studies have looked at the impact of a water table lowering on carbon fluxes in different types of peatlands. However, these studies were conducted within a time frame that did not allow the examination of vegetation changes due to the water table lowering. To be able to predict the fate of peatlands with changing climate and potentially lower water tables, the effect of a change in vegetation has to be considered. To bridge this gap, I conducted a study along a drainage gradient resulting from the construction of a drainage ditch 85 years ago in a portion of the Mer Bleue bog, located near Ottawa, Canada. According to water table reconstructions based on testate amoeba, the drainage dropped the water table by approximately 18 cm. On the upslope side of the ditch, the water table partly recovered and the vegetation changed only marginally. However, on the downslope side of the ditch, the water table stayed persistently lower and trees established (Larix and Betula). The importance of Sphagnum decreased with a lower water table, and evergreen shrubs were replaced by deciduous shrubs. The water table drop and subsequent vegetation changes had combined and individual effects on the carbon functioning of the peatland. Methane fluxes decreased because of the water table lowering, but were not affected by vegetation changes, whereas respiration and net ecosystem productivity were affected by both. The carbon storage of the system increased because of an increase in plant biomass, but the long-term carbon storage as peat decreased. Several steps need to be taken to allow for the appropriate representation of water table disturbances in peatland carbon modelling. The modelling of the effect of water table drop, along with vegetation changLes tourbières sont une composante importante du cycle global du carbone, séquestrant le tiers du carbone contenu dans les sols. L'accumulation de la tourbe dépend de deux facteurs principaux: l'hydrologie et la végétation. Des études ont abordé l'impact d'un abaissement de la nappe phréatique sur les flux de carbone des tourbières. Cependant, l'échelle temporelle de ces études ne permet pas de voir de changements de végétation en réponse à un abaissement de la nappe phréatique. Pour être en mesure de prédire le futur des tourbières dans un climat potentiellement plus sec, les effets des changements de végétation doivent êtres considérés. J'ai donc utilisé un site comprenant un gradient de conditions hydrologiques résultant du creusage d'un canal de drainage sur la tourbière Mer Bleue, près de Ottawa. D'après des reconstructions hydrologiques basées sur des assemblages de rhizopodes, le drainage a abaissé de façon permanente la nappe phréatique d'environ 18 cm. Sur le côté en amont du canal, la nappe phréatique s'est partiellement rétablie et la végétation a peu changé. Par contre, sur le côté aval du canal, la nappe phréatique a été abaissée de façon permanente et des arbres se sont établis (Larix et Betula). Avec l'abaissement de la nappe phréatique, la sphaigne est devenue moins importante et des arbustes à feuilles caduques ont remplacé les sempervirents. Les changements hydrologiques et de végétation ont eu des effets individuels et combinés sur les flux de carbone de la tourbière. Les flux de méthane ont été réduits par l'abaissement de la nappe phréatique, mais n'ont pas été affectés par les changements de végétation, mais la respiration et la productivité nette de l'écosystème ont été affectées par les deux. La séquestration du carbone a ainsi augmenté due à une augmentation de la biomasse végétale, mais la séquestration à long terme du carbone dans la tourbe a diminué. La simu
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Wiklund, Sara. « Long-term glacier mass balance of Nordenskiöldbreen, Svalbard ». Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-295789.
Texte intégralRésumé :
The global warming that’s taking place have an impact over the Earth and the glaciers on Svalbard are undergoing rapid changes as a result. The annual air temperature has been rising on Svalbard since the early 1900’s and in a climate projection expected temperatures continue to rise. The glacial mass balance is important for monitoring glacier response to climate change. In this study the mass balance of Nordenskiöldbreen from 1957 to 2016 is modelled with a temperature-index model. The meteorological data used in the model, precipitation and air temperature, has been measured at a weather station located in Longyearbyen since 1957. The long simulation run makes trends in mass balance, precipitation and air temperature apparent. The mass balance can also be correlated to the temperature and precipitation, which provide important information on how these affect the behavior of glaciers. The results obtained can be used to predict how glaciers change in the future with climate change. In the simulation Nordenskiöldbreen’s mass balance has a negative trend, precipitation doesn’t have any trend and air temperature has a positive trend. The long-term mass balance is controlled by air temperature and the short-term interannual mass balance is caused by precipitation fluctuations.Den globala uppvärmningen som sker just nu har en påverkan över hela jorden och glaciärer på Svalbard genomgår snabba förändringar som följd. På Svalbard har den årliga medeltemperaturen stigit sedan början av 1900-talet och i en klimatprojicering förväntas temperaturen att fortsätta stiga. Den glaciala massbalansen är viktig för att övervaka glaciärers respons till klimatförändringar. I detta arbete modelleras Nordenskiöldbreens massbalans från 1957 till 2016 med hjälp av en temperaturindex modell. Den meteorologiska data som används i modellen, nederbörd och temperatur, har mätts vid en väderstation i Longyearbyen sedan 1957. Med den långa tidsperioden i modellen blir långsiktiga trender i massbalans, nederbörd och temperatur tydliga. Massbalansen kan även korreleras mot temperatur och nederbörd, vilket ger viktig information om hur dessa påverkar glaciärers beteenden. De resultat som framkommer kan användas för att förutspå hur glaciärer förändras i framtiden med en klimatändring. I simuleringen har Nordenskiöldbreens massbalans en negativ trend, nederbörd har ingen trend och temperatur har en positiv trend. Det är temperatur som styr den långsiktiga massbalansen och den kortsiktiga mellanårs-massbalansen styrs av nederbörds fluktuationer.
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Harvey, Gemma. « Characterising physical habitat at the reach scale, River Tern, Shropshire ». Thesis, University of Nottingham, 2006. http://eprints.nottingham.ac.uk/10264/.
Texte intégralRésumé :
Characterisation of the complex geomorphological and ecological structure of river channels into workable units of instream habitat is a key step in enabling the assessment of habitat for river management purposes. The research presented in this thesis uses a range of methodological approaches at a variety of spatial scales in order to improve the conceptual basis of habitat characterisation at the reach and sub-reach scale. An appraisal of published works is used in conjunction with an extensive analysis of habitat features for sites across the UK, and intensive field studies on the River Tern, Shropshire, to improve the conceptual basis and ecological validity of the 'physical biotope' as the basic unit of instream habitat. Physical biotopes demonstrate correlations with biologically functional habitat units at relatively broad scales, suggesting that assemblages of habitat units may provide the most appropriate level of simplification of aquatic habitat structure. A simplified, but more transferable classification using biotope assemblages is suggested, with potential application to a range of instream assessment and river design needs. Reach-scale field surveys reveal complex and dynamic relationships between channel hydraulics and morphology and highlight the influence of sampling design and hydrological context on the outcomes of rapid field surveys. A microscale research component addresses within-biotope variation at small scales by focusing on high frequency flow behaviour and sediment transport mechanisms which have, to date, been largely overlooked in biotope studies. This provides both detailed descriptions of hydraulic behaviour, and an indication of differences in internal spatial and temporal heterogeneity between biotopes, with implications for instream biota.
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Sanderson, Samuel Scott. « Sense of Place in an Unincorporated Community : ». Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4763.
Texte intégralRésumé :
Abstract
Residents of communities that are at the edge of the rural-urban divide are likely to have many senses of place reflective of the changes occurring around them. As the place where they have resided in and identify with becomes transformed by changes in land use and social composition, these residents may be forced to either adapt or leave. Often overlooked, these individuals may feel as if the place where they have long resided is no longer their home. As the familiar routes, stores, and neighborhoods give way to new highways, big name stores, and exclusive subdivisions, their understanding of its sense of place becomes challenged.
This thesis seeks to understand changing senses of place among residents in Lutz, an unincorporated community at the edge of the city of Tampa in Florida. Using a humanistic geography approach which focuses on individual perceptions, nine semi-structured interviews were conducted on questions related to community boundaries, everyday experiences of demographic and land use transformations, and possible futures of the community. Further background on the community was collected by traveling through it and analyzing media accounts which provided both historical and contemporary perspectives on its cultural landscapes.
One of the main findings of this thesis is that the unincorporated nature of this community adds a unique dimension to discussions of its socio-spatial transformations since the role of boundaries in sense of place becomes complicated here. Thus, in contrast to firm lines drawn by cartographers or postal agencies, cultural boundaries have a high degree of subjectivity and are often at odds with official demarcations. Overall, this thesis highlights the value of focusing on residents of unincorporated communities in order to build more complex notions of place-based identities.
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Håkansson, Johan. « Changing population distribution in Sweden : long term trends and contemporary tendencies ». Doctoral thesis, Umeå universitet, Kulturgeografiska institutionen, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-100712.
Texte intégralRésumé :
The aim of the thesis is to describe and analyse the population redistribution in Sweden at different geographical levels from the beginning of the 19th century to the end of the 20th century. The analysis is approached in three different ways. First, the redistribution at different geographical levels is analysed (papers I and II). Second, the changing accessibility between people (interpersonal accessibility) is analysed from the beginning of the 19th century to the end of the 20th century (paper II). Third, the impacts of fertility, mortality, internal migration, international migration and geographical variations in age composition on population distribution are analysed for the last decades (papers I, III and IV). Measurements of concentration have been used in order to analyse the changing population distribution. For the analysis of changing interpersonal accessibility the average population within the daily reach has been calculated for different times. In order to analyse the impacts of fertility, mortality, migration and geographical variations in age composition the actual redistribution of the population is compared with the redistribution generated by a number of counterfactual scenarios. To analyse the impact of international migration the changing distribution of the population in different immigrant groups is compared to the distribution of the Swedish population. Some conclusions drawn from the thesis are: 1. There is no overall trend in the population redistribution towards either concentration or dispersion. The redistribution pattern depends on the time perspective and the geographical level chosen. The population has been both concentrated and dispersed since the beginning of the 19th century. This applies to all investigated geographical levels. In the five identified phases of the redistribution the most common pattern is that concentration and dispersion of the population exist simultaneously on different geographical levels. The total effect of the redistribution between 1810 and 1990 is that today the population is more dispersed at macro-regional level, while it is more concentrated at local and regional level. 2. Based on assumptions about the daily reach, an average person today has access to about 100 times more people locally compared with the beginning of the 19th century. The most important process for the increased accessibility has been the redistribution of the population. The process that has had the least impact is the assumed increase in daily reach. However the importance of the investigated processes changes over time. Since 1950 the increasing reach has been the most important process. However, the rate by which interpersonal accessibility increases has slowed down since 1950. 3. The main demographic factor behind the redistribution since 1970 is the geographical differences in age composition and its effects on the natural population change. It is demonstrated that this factor lies behind the trend towards increasing concentration in Sweden, while the impact of migration affects the fluctuations from this trend to a greater extent. 4. The study shows that immigration concentrates the population, while the internal migration during the 1970s and periodically during the 1980s dispersed the population. However during the 1990s the internal migration has had a concentrating effect on the spatial distribution of the population.Diss. (sammanfattning) Umeå : Umeå universitet, 2000, härtill 4 uppsatser
digitalisering@umu
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Alexander, Laura A. « Meaning of place : exploring long-term resident's attachment to the physical environment in northern New Hampshire / ». [Yellow Springs, Ohio] : Antioch University, 2008. http://www.ohiolink.edu/etd/view.cgi?acc_num=antioch1219972881.
Texte intégralRésumé :
Thesis (Ph. D.)--Antioch University New England, 2008.Title from PDF t.p. (viewed Oct. 24, 2008). "A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Environmental Studies at Antioch University New England (2008)."--The title page. Advisor: Thomas Webler, Ph. D. Includes bibliographical references (p. 156-159).
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Roberts, Jonathan Wesley. « Assessing intra-seasonal land surface change and long term trends in the succulent Karoo biome using coarse resolution satellite and interpolated rainfall surfaces ». Master's thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/4801.
Texte intégralRésumé :
Includes bibliographical references (leaves 132-151).The Succulent Karoo is a biodiversity hot spot situated along the west coast of southern Africa. While it is predominantly recognized as a west coast vegetation type its borders stretch as far east as Steytlerville in the Little Karoo. The area contains the largest number of endemic succulent species in the world and harbors nearly 10 percent of the of the total number of succulent species worldwide. Furthermore, spring mass-flowering events draw thousands of tourists to the region, providing welcome input to the local economies. The floral diversity is however, under threat from various environmental forces. These forces include inappropriate land use practices resulting in Land Degradation and the ever-present threat of Climate Change.
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Nguyen, Thi Bach Le. « Discovery of active secondary metabolites from Paenibacillus odorifer, a lichen-associated bacterium ». Thesis, Rennes 1, 2018. http://www.theses.fr/2018REN1S098/document.
Texte intégralRésumé :
Les bactéries qui sont des sources prolifiques d'antibiotiques et des fournisseurs importants d’agents pharmaceutiques peuvent produire une grande variété de métabolites. Ainsi, la découverte de métabolites issus bactéries est un nouveau challenge pour les chimistes. Parmi ces sources, les lichens sont admis comme niches intéressantes de nouvelles bactéries et de nouveaux composés bactériens. Par conséquent, les communautés de micro-organismes associées aux lichens sont devenues des sources prometteuses pour la production de composés naturels actifs. Dans cette thèse, nous avons concentré notre travail sur l'isolement des bactéries de Rhizocarpon geogaphicum, l'un des lichens crustacés les plus populaires vivant sur la roche. Parmi les souches isolées, Paenibacillus odorifer a été sélectionnée pour poursuivre les travaux visant à produire des composés actifs. Après des étapes d’optimisation de culture, l’étude des extraits issus des cultures de P. odorifer soit par le bioréacteur soit en Erlenmeyer a permis l’isolement des métabolites : un polysaccharide antioxydant, deux dérivés tert-butylphénoliques cytotoxiques issus de la bioaccumulation et de la biotransformation de précurseurs, d'un nouvel alcaloïde cytotoxique, de deux diols, de deux dérivés de type furfural et quelques autres composés connus. Des hypothèses de biosynthèse ont pu être proposés pour certains composés. La diversité des métabolites isolés de P. odorifer indique que cette espèce possède un grand potentiel de production des composés actifs et est une bactérie utilisatrice de substrats tert-butyl phénoliquesBacteria which are prolific sources of antibiotics and important suppliers to the pharmaceutical agents can produce a wide variety of metabolites. Thus finding metabolites from the bacterial lineages represented new interests for chemists. Among that, lichens are admitted as a rich source of new bacterial lineages and novel bacterial compounds. Therefore, microorganism communities associated with lichens became significant subjects as great potential for the production of active natural compounds. In this thesis, we focus our work on the isolation of bacterial lineages from the lichen Rhizocarpon geographicum, one of the most popular crustose lichens dwelling on the rock. Among the strains isolated, Paenibacillus odorifer was selected for further work to produce active compounds. After the culture optimization steps, the study of extracts from the P. odorifer cultures either in the bioreactor or in Erlenmeyer flask led to the production of metabolites: an antioxidant polysaccharide, two cytotoxic tert-butylphenol derivatives which came from the bioaccumulation and biotransformation of precursors, a novel and cytotoxic alkaloid compound, two diol compounds, two furfural derivatives and some other known compounds. Putative biosynthetic pathways have been proposed for some compounds. The diversity of metabolites isolated from P. odorifer highlighted that this species possessed a great potential of the production active compounds and were a new case of tert-butyl phenol utilizing bacterium
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Jahangir, Muhammad Nasir, et Muhammad Fahadullah. « Statistical Analysis of Team Training in Emergency Management Simulator System ». Thesis, Linköping University, Department of Computer and Information Science, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-51990.
Texte intégralRésumé :
In this thesis work, we compare the results obtained from two kinds of teams forming a hierarchical organization participating in a fire fighting simulation environment called as C3Fire. First kind of teams used paper-based maps for spatial reasoning of the command tool while the other kind of teams has GIS based maps with full access to positioning data of the fire fighting units as well as sensor information about fire break.
The collected data was from 11 teams of each kind having 6 members in each team making a total of 132 participants belonging to different parts of the world.
We made a statistical analysis on the data with help of T-Test statistical medhod and a tool is designed by using Java as programming language and PostgreSQL database for importing data from log files and then applying statistical T-Test method on the fetching data from log files.The results are stored in database as well as excel files. Then a comparison is done to analyze the unit performance, communication and efficiency of both kinds of teams.
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Lai, Ling-yan Edith, et 賴靈恩. « Effects of cooperative learning on student learning outcomes and approaches to learning in sixth form geography ». Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1991. http://hub.hku.hk/bib/B38627292.
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Prokop, Daniel. « The determinants of University spinout formation and survival : the UK context of network, investment, and management team effects ». Thesis, Cardiff University, 2017. http://orca.cf.ac.uk/103936/.
Texte intégralRésumé :
UK universities attract increasing attention from policy-makers searching for regional solutions to economic development challenges. Consequently, university spinout companies have featured prominently in UK policy-making, as they embody a transfer of knowledge of the most complex and comprehensive character. However, whilst the positive contribution of spinout companies to regional economies is widely accepted, little is known of how to ensure high quality outcomes from such knowledge commercialisation activities. This thesis aims to improve the understanding of this problem by examining the elements that contribute to the success of academic spinouts in the UK context. It investigates dual meaning of success: spinout formation and survival, conceptualised here as embedded in university networks composed of multiple actors. It is set within a post-positivistic paradigm and employs an explanatory sequential mixed methods research design. The quantitative part identifies the elements contributing to the success of spinout companies using data on 870 spinout companies extracted from university websites and supplemented with financial, economic and educational databases; and leads to the qualitative part, explaining differential performance of spinout companies across UK regions with data collected through semi-structured interviews conducted at four illustrative university networks. It is found that the success of spinout companies depends on networks, investment, and management teams. However, the formation and survival of spinout companies differs across a number of elements: technology transfer offices, business incubators, other actors, and geography; suggesting bi-dimensional complexity across space and success measures. The variable spatial performance of university networks determining spinout company outcomes is explained by connectedness, filtration and time: successful spinout companies originate from university networks that have capability to build and exploit network capital. It is suggested that regional innovation systems require designs oriented towards these diverse spinout success outcomes, formation and survival-based, with strong local adaptations.
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Conver, Joshua L. « Saguaro Cactus (Carnegiea gigantea) Growth and Population Dynamics in Multiple Physiographic Settings of Saguaro National Park, Arizona, USA ». University of Cincinnati / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1613745513093036.
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Olszak, Candace A. « The Impacts of Weather on a Mid-American Conference University Football Team and Players' Perceptions Regarding Weather ». Kent State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=kent1334330057.
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Jacob, Hassler. « Long term trends of residential segregation in relation to housing policy in Stockholm : Following indicators of residential segregation over time through spatial analysis ». Thesis, Umeå universitet, Institutionen för geografi, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-159964.
Texte intégralRésumé :
This thesis explores the development of residential segregation over a long time period in Stockholm, Sweden. By following the spatial distribution of two socio- economic indicators and two indicators of housing characteristics between 1930 and 2015, it describes how changing housing policy has affected the indicators. Historic data was gathered and compiled in a longitudinal data base. Spatial analysis of the variables produced results that indicate spatio-temporal variation in all variables, and indicate a central-peripheral pattern that has developed and persisted for long time periods. Variation in spatial distributions of the variables is furthermore connected to changes in undertaken housing policy. Regression models also indicate that the characteristics of residential segregation has arguably been different in different times. The long time period is argued to be important in segregation research because of the longevity of many segregation processes. Following continuous indices of residential segregation over long time periods is important as it may help us understand contemporary trends better, conversely creating better knowledge for policy makers when counter segregation policy is implemented. Long time approaches are, however, lacking the literature, motivating the analysis performed in this thesis.
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Spangler, Ian. « “ONE MORE WAY TO SELL NEW ORLEANS” : AIRBNB AND THE COMMODIFICATION OF AUTHENTICITY THROUGH LOCAL EMOTIONAL LABOR ». UKnowledge, 2018. https://uknowledge.uky.edu/geography_etds/57.
Texte intégralRésumé :
Since 2014, Airbnb has been the poster-child for an impassioned debate over how to best regulate short-term home rentals (STR’s) in New Orleans, Louisiana. As critical perspectives toward on-demand economic practice become increasingly common, it is important to understand how the impacts of STR platforms like Airbnb extend beyond the realm of what is traditionally conceptualized as the economic (i.e., pressure on housing markets). In this thesis, I explore the ways in which Airbnb recalibrates the spatial and temporal rhythms of everyday neighborhood life for people external to the formal trappings of an STR contract. Drawing in particular on theories of authenticity and feminist political economy, I argue that locals’ emotional labor of “playing host” is necessarily enrolled into the creation of value for Airbnb, and is essential to the reproduction of the platform’s business model and marketing rhetoric.
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Molinari, Claire Marcella. « The environment, intergenerational equity & ; long-term investment ». Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:30dd270b-3f0f-4b8b-979e-904af5cb597b.
Texte intégralRésumé :
This thesis brings together two responses to the question ‘how can the law extend the timeframe for environmentally relevant decision-making?’ The first response is drawn from the context of institutional investment, and addresses the timeframe and breadth of environmental considerations in pension fund investment decision-making. The second response is related to the context of public environmental decision-making by legislators, the judiciary, and administrators. Three themes underlie and bind the thesis: the challenges to decision-making posed by the particular temporal and spatial characteristics of environmental problems, the existence and effects of short-termism in a variety of contexts, and the legal notion of the trust as a means for analysing and addressing problems of a long-term or intergenerational nature. These themes are borne out in each of the four substantive chapters. Chapter III sets out to demonstrate the theoretical potential of pension funds to drive the reduction of firms’ environmental impact, and, focusing particularly on the notion of fiduciary duty, explores the barriers that stand in their way. Chapter IV provides a practical application of the theoretical recommendations outlined in its predecessor. It provides a framework outlining how pension funds might implement a longer term, more sustainable approach to investing. The second half of the thesis, operating in the context of public environmental decision-making, is centred upon a particularly poignant legal notion with respect to the environment and time: the concept of intergenerational equity. Just as the first half of the thesis deals with the timeframes relevant to investment decision-making by pension funds within the bounds of fiduciary duty, largely a private law affair with public implications, the second half of the thesis is concerned with the principle of intergenerational equity as a means for extending the decision-making timeframe of legislative, judicial and administrative decision-makers. As previous analyses of the concept of intergenerational equity provide little insight into its practical implications when applied to particular factual situation, Chapter V sets out the structure of the principle of intergenerational equity as revealed by case law. Chapter VI brings together the issues from the first three papers by conceptualising intergenerational equity in resource management as an issue of long-term investment. Long-term environmental decision-making faces many obstacles. Individual behavioural biases, short-term financial incentive structures, the myopic pressures of the electoral cycle and the tendency of the common law to reinforce the (often shorttermist) status quo all present significant barriers to the capacity of both private and public decision-makers to act in ways that favour the longer term interests of the environment. Nonetheless, this thesis argues that there is reason for hope: drawing upon the three themes that underlie all of the substantive Chapters, it articulates potential legislative changes and recommends the adoption of particular governance structures to overcome barriers to long-term environmental decision-making.
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Vangile, Kirsten M. « Childhood Cancer Survivors : Patient Characteristics ». Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/iph_theses/51.
Texte intégralRésumé :
Survivors of childhood cancer are a relatively new phenomenon in the medical world. The introduction of treatment protocols in the 1970s started a trend in curing children of cancer that historically had been a death sentence. Under these treatment protocols children were given different treatment regimens based on past research that helped remove cancerous cells from their bodies, but were later found to be the cause of treatment related morbidities years into the future; for most survivors roughly ten to 20 years post treatment. These morbidities, commonly called late-effects, are the prime reason that survivors of childhood cancer need to participate in survivorship care. Survivors of childhood cancer are particularly vulnerable to late-effects because the majority of them receive their treatment at a time when their bodies are still growing and developing. Survivorship care services vary by site, but all maintain the common goals of providing long-term follow up for the survivor and education about the ways in which treatments may affect a survivors’ health as they age. Similar to many other facets of healthcare and medicine, there are many populations who do not participate in survivorship care. The purpose of this research is to identify possible barriers to care, assess the level of impact these barriers have upon the survivor’s potential for participation and provide suggestions as to how these barriers can be mitigated. Additionally, this research highlights areas that need further research and analysis.
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Alcidonis, Sendy Guerrier. « The Social Networks of Haitian Immigrants Employed in the Long-term Care Industry in Metropolitan Philadelphia : Complex Intersections of Race, Nationality, Class, and Gender ». Diss., Temple University Libraries, 2016. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/367943.
Texte intégralRésumé :
GeographyPh.D.
This study explains the labor market outcomes of foreign-born Haitian women and men employed in the long-term care industry in Philadelphia, PA. The study is a feminist geographic analysis of their social networks related to migration and employment. This analysis is significant for two reasons. First it provides a more nuanced understanding of the linkages between the geography of networks, migration, and labor market outcomes than currently exists. Furthermore by exploring how people’s multiple social identities shape the geography of social networks, migration, and labor market outcomes, the study integrates geographic and intersectional analyses and brings feminist geography to the center of contemporary feminist debates. I engaged in an inductive qualitative research study consisting of interviews and participation observation fieldwork. I conducted in-depth interviews with 18 women and 12 men currently working in the long-term care industry, along the nursing occupational hierarchy. These interviews focused on explicating the relationships among the geography of place-based social networks, the dynamic and complex intersections of multiple social identities, and occupational mobility. Interviews examined the nature, spatial extent and significance of the social network connections that shaped their labor market, educational, and migratory histories, as well as their current daily activities. I interviewed six key informants from Haitian community groups and immigrant nonprofit organizations to gain additional information about the Haitian community in Philadelphia and the role of social network composition and use. I also interviewed seven key informants affiliated with nurse training and job placement organizations to gain more information about the trends in this field. Finally, I conducted participant observation fieldwork at three nursing program recruitment information sessions. This research is a timely intervention that brings together the academic literature of feminist geographic inquiry about urban labor markets, feminist geographic inquiry about migration, migration studies, and the feminist theory of intersectionality. The scholarship of each of these has developed along parallel but separate trajectories. By bringing them in conversation with one another, this research makes important contributions to a number of important theoretical and empirical debates within each of them. The project advanced migration studies by documenting the multiscalar geography of social networks and how the complex intersections of race, class, nationality and gender shape network composition. Furthermore the research linked co-ethnic social networks to occupational mobility within the long-term care industry. This study advanced feminist theory by integrating a Black Feminist approach to intersectionality with geographic concepts of mobility, space and place to develop a new methodological tool, the Social Relations Chart. This provides a new way to examine intersectionality in practice. Finally, this study advanced feminist geographic inquiry by documenting the complex intersections and operation of the power hierarchies of race, nationality, class and gender in the workplace in a manner not previously documented in the urban labor market literature. In sum, this research brings these bodies of scholarship together and extends collective knowledge about the mechanisms by which mobility, power, place and space are shaped by multiscalar social relations.
Temple University--Theses
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Palmgren, Rikard. « Reconstructing the Long-Term Mass Balance of Brewster Glacier, New Zealand, Using a Degree-Day Approach ». Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-324325.
Texte intégralRésumé :
Varmare klimat är något som kontinuerligt påverkar glaciärer planeten över och har under det senaste århundrandet vidtagit en global ökning av negativa massbalanser. Denna trend kan bidra till variationer i havsnivån och orsaka problem med översvämningar över hela världen. Övervakning och observation av världens glaciärer är därför väldigt viktigt och genom att skapa modeller som tillåter insyn i glaciärernas respons till atmosfärisk fluktuation går det att åstadkomma en djupare förståelse för hur den globala uppvärmningen kommer att utvecklas. I detta projektet återskapas massbalansen för Brewster Glacier, Nya Zeeland, för perioden 2005 – 2015 genom tillämpning av graddagar. Modellen har försetts med data från ett nyligen genomfört nedskalningsprojekt som har producerat atmosfäriska data för perioden 1979 – 2015 vilket tillåter modellen att köras. Resultaten som presenteras kommer att bidra till större inblick i graddags-modellen om huruvida tillvägagångssättet att använda enkel temperatur- och nederbördsdata är tillförlitligt för att porträttera massbalansen för glaciärer.Warmer climate is something that is continuously affecting glaciers across the planet and has during the last century gained a global increase in negative mass balances. This trend has contributed to sea-level rise and had other impacts on water resources. Monitoring and observing the worlds glaciers is therefore very important and by creating models that allows insight in the glacier response to atmospheric fluctuation, it is possible to obtain deeper knowledge on how the global warming will develop. In this project, the mass balance of Brewster Glacier, New Zealand, is reconstructed for the period 2005 – 2015 using a degree-day approach. The input for the model has been obtained from a recent downscaling project that has produced atmospheric data over the period 1979 – 2015 that allows the model to run at a daily temporal resolution. The results presented are going to contribute to a greater insight in the degree-day model as to whether the approach of using simple air temperature and precipitation data are reliable to portray the mass balance of glaciers.
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Grenot, David. « Short-Term Surface Velocity Changes During Summer in the Lower Part of the Ablation Area Using Differential GPS Survey, Storglaciären, Sweden ». Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-277288.
Texte intégralRésumé :
short time scale. Four differential GPS stations were installed in the lower ablation area of Storglaciären in Sweden for one week in August 2012. The position data over the period were then compared with the environment information including temperature, precipitation, known hydrology and topography.The instantaneous velocity results show 9 acceleration events in correlation to temperature and precipitation. The increase of the meltwater inputs drive increases of the motion supposedly through water pressures and basal sliding.Strain determination using the stations geometry showed that the lower part of the survey area had an extensive behavior when the upper part was showing compressive properties. A deformation event occurring the 14th of august shows an elongation deformation along the centerline from the front of the glacier resulting in a lateral compression on the upper part due to shear stress closer to the margin.It was proposed that the force driving the elongation is due to the increase of water pressure on the front of the glacier where the internal hydrological system pass from a complex multi-branched system to a channelized output.Syftet med detta projekt var att studera sambandet mellan en glaciärs hydrologi och isrörelse under korta tidsperioder (minuter till timmar). I augusti 2012 installerades fyra differentiella GPS-stationer under en veckas tid i nedre ablationsområdet på Storglaciären i Sverige. Positionsdata under perioden jämfördes sedan med miljöinformation inklusive temperatur, nederbörd, avrinning från glaciären och topografi.De uppskattade hastighetsresultaten visar på 9 olika accelerationshändelser som relaterar till tempe-ratur och nederbörd. En ökad införsel av smältvatten driver upp vattentrycket vid glaciärens botten som minskar friktionsmotståndet och glaciären får ökad basal glidning.Isdeformationsberäkningar mellan DGPS-stationerna visar att den nedre delen av undersök-ningsområdet hade extensionell deformation i isrörelseriktningen medan den övre delen visade kompression vinkelrätt mot denna riktning. Deformationshändelsen den 14 augusti visar det motsatta med extensionell deformation längs mittlinjen från fronten av glaciären vilket resulterar i en lateral kompression i den övre delen av det undersökta området kanske orsakade av skjuvspänning vid marginalen.Det föreslås att utsträckningen av glaciären under dessa händelser är på grund av en ökning av vattentrycket i det område där det interna subglaciala hydrologiska systemet ändras från en komplex multigrenade system högre upp i ablationsområdet till ett kanaliserat system vid fronten.
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Hansson, Veronica, et Nathalie Olausson. « Utomhusundervisning för att främja lärandet - En pedagogisk undersökning om minnet och inlärning ». Thesis, Malmö högskola, Lärarutbildningen (LUT), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:mau:diva-30095.
Texte intégralRésumé :
Grundtanken med detta arbete är att se om utomhuspedagogik möjligtvis främjar lärandet och om det går att finna stöd inom neurologisk forskning för att ta reda på om lärandet stimuleras vid användandet av utomhusundervisning. Undersökningar har genomförts för att se om lärare och elevers syn på utomhusundervisning sammanfaller. Arbetet bygger på litteraturstudier, intervjuer, en observationsstudie, samt enkätundersökningar för att besvara forskningsfrågorna. I denna studie har det framkommit att utomhusundervisning främjar lärandet, främst beroende på de multipla sinnesintryck som utomhusvistelsen skapar. Denna iakttagelse stöds även av neurologisk och pedagogisk forskning. Det har även framkommit att lärare och elever tycker att utomhusundervisning är ett viktigt och positivt inslag i undervisningen.
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Kolokotronis, Nikolaos. « The Phenomenon of Airbnb in Havana : A late-capitalism phenomenon in one of the last remaining socialist countries ». Thesis, Stockholms universitet, Romanska och klassiska institutionen, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-185706.
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Olofsson, Irma. « "There's no I in team" : A study of roles of civil society in Holmsund, and it’s connection to constructions of Holmsund ». Thesis, Umeå universitet, Kulturgeografi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-149647.
Texte intégralRésumé :
The civil society and civic engagement is a prerequisite for democracy (Putnam, 1994), and in the form of the popular movements it has in many ways defined the Swedish democracy. This thesis focuses on the locality Holmsund located in the municipality of Umeå, Holmsund has a history that are in ways defined by activeness from civil society in similarity with many other places in Sweden (Ambjörnsson, 2001). Through interviews with people active connected to voluntary associations in Holmsund, and the use of narrative analysis this thesis tries to understand how what roles civil society has in Holmsund today; with specific interest in the rural context. Central to this is the understanding of space as relational and in many ways defined by power relations, and in particular relationship between centre-periphery. The combination of the centre-periphery relationship and the neo-liberal restructuring of the Swedish economy from being characterized by wealth distribution to wealth contributing in order to prosper has among other things lead to a decrease in services and increase inequality, both in urban peripheral places or as in this case, rural places. A part of how voluntary associations perceive their role in a rural and local context, is a role of counteracting the effects of inequality but mainly voluntary association are occupied with creating a good living environment within their local community. A part of the increasing inequality is that it enhances the identification with the local context which creates a common social reality among the inhabitants which serves as ground for organization. Through place attachment there seem to be an identification in between a significant presence and importance of civil society and the place Holmsund, this contributes to Holmsund being constructed as a civic community.
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Royer, Sarah-Jeanne. « Links Between Dimethylated Sulfur and Phytoplankton Photophysiology in the Surface Ocean Geographical Paterns and Short-Term Variability = Relación entre el Dimetilsulfuro y la Fotofsiología del Fitoplancton en la Superfcie del Océano. Patrones Geográfcos y Variabilidad a Corto Plazo ». Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/336378.
Texte intégralRésumé :
Dimethylsulfide (DMS) and its algal metabolite precursor, dimethylsulfoproprionate (DMSP), are major players in the oceanic and atmospheric sulfur cycle. DMS is the most abundant volatile organic sulfur compound in the upper ocean and its global emission accounts ca. 28 Tg S per year, thus representing the main natural source of sulfur to the troposphere and about 30% of the global (including anthropogenic) sulfur emissions. DMS cycle has been the subject of hundreds of studies over the last 27 years because of its hypothesized role in climate regulation (CLAW hypothesis), where it has been postulated to regulate the number of cloud condensation nuclei over the oceans and hence reduce the total amount of solar radiation reaching the Earth's surface. However, this simplistic view has not been proven so far as the relationship between oceanic DMS concentrations and solar radiation is complex and involves several different actors. Both DMS and DMSP (hereafter referred together as DMS(P)) concentrations are variable in the surface ocean and physics, chemistry and biology in the photic upper layer all play important roles in their cycling, from DMSP biosynthesis to DMS ventilation, with their relative importance varying amongst the diversity of biomes and pelagic ecosystem settings encountered in the world's oceans. Hence, predicting DMS at a global scale needs an intricate understanding of processes affecting its cycle at all temporal and spatial scales. The premise of the thesis is to contribute to a better understanding of the different physical, chemical and biological drivers that shape the DMS(P) cycle in polar, tropical and sub- tropical oceanic environments from very short to longer term temporal scales. This work combines an extensive database of DMS measured at low and high frequency, in different regions and across environmental gradients, and at temporal scales that span from minutes to seasons. In the short term (minutes to hours) , exposure to UVR seems to play an important role in the physiological response of phytoplankton cells and DMS(P) production. Solar radiation also dictates the pace of variability in DMS concentration over diel (day-night) cycles, where DMS seems to be surprisingly coupled to photobiological clocks. However, while gross biological DMS production generally increases with light exposure, concentration depends on the net effect of production and losses by photolysis, microbial consumption and ventilation. As a result, no single pattern for diel DMS oscillations is valid for the global oceans. Extensive data gathering across many biogeographical provinces in the tropical and subtropical oceans confirmed that DMS distribution is better explained by abiotic factors (solar radiation, vertical mixing, light absorption by organic matter) and phytoplankton physiology (efficiency of photosystem II) than by indicators of plankton abundance and general activity. Our work also shows that inferences about the causes of the variability of DMS depend on the frequency of the data collection. During a circumnavigation cruise, data collected at low frequency translated into relatively low variation factor (5.1) within individual biogeochemical provinces. In contrast, high frequency data revealed much higher variation factor (96) because of the capture of sub-mesoscale variability. Statistical work on high frequency data showed that critical variability distances for DMS average 15 and 50 km for coastal and open ocean marine provinces, respectively. DMS distribution patchiness increases with productivity and latitude, with important implication for designing fieldwork and computational mapping of DMS concentration and emissions. Overall, this thesis sheds light on the complex interplay of physical, chemical and biological variables in the DMS cycle and emphasizes the difficulty of finding simple environmental drivers of quantitative applicability at global scales.El dimetilsulfur (DMS) i el seu precursor algal dimetilsulfoniopropionat (DMSP) són part fonamental del cicle del sofre als oceans i l’atmosfera. El DMS és el compost volàtil de sofre més abundant a l’oceà superficial, que n’emet a l’atmosfera una quantitat aproximada de 28 Tg S l’any. Això representa la principal font natural de sofre a la troposfera, i aproximadament un terç de l’emissió global de sofre, incloent-hi l’antropogènica. El cicle del DMS ha estat objecte de centenars d’estudis en els darrers 27 anys, motivats sobretot per la hipòtesi CLAW que proposava que el DMS és la principal font de nuclis de condensació de núvols sobre els oceans i, d’aquesta manera, ajuda a regular la quantitat de radiació solar que arriba a la superfície de la Terra i, de retruc, el clima. Aquesta hipòtesi, avui vista com a simplista, no s’ha arribat a provar totalment, sobretot perquè la relació entre radiació solar i concentració i emissió de DMS és complexa i hi intervenen múltiples factors. Tant la concentració del DMS com la del DMSP (que referim conjuntament com a DMS(P)) varien força en l’oceà superficial com a resultat de processos que van de la biosíntesi del DMSP a la ventilació del DMS. Aquests processos, a la vegada, responen a factors i actors físics, químics i biològics, la importància relativa dels quals varia entre biomes i configuracions de l’ecosistema pelàgic. Com a conseqüència, predir la distribució del DMS a escala global demana un coneixement profund de tots els processos implicats, a totes les escales temporals i espacials. L’objectiu general de la tesi és contribuir a conèixer millor els factors físics, químics i biològics que governen el cicle dels DMS(P) en aigües polars, subtropicals i tropicals a escales temporals molt diverses. El treball combina una base de dades extensa de mesures de DMS obtingudes a baixa i alta freqüència, en regions diverses, a través de gradients ambientals, i d’escales de temps que van des dels minuts fins a les estacions de l’any. A més curt termini (minuts a hores), l’exposició a la llum UV sembla jugar un paper important en la resposta fisiològica del fitoplàncton i la subseqüent producció de DMS(P). La radiació solar també dicta el ritme de variació de la concentració de DMS en cicles dia-nit, en què el DMS es mostra sorprenentment acoblat amb els rellotges fotobiològics. Tanmateix, malgrat que la producció biològical bruta de DMS generalment augmenta amb l’exposició a la llum, la concentració depèn de l’efecte net d’aquesta producció amb les pèrdues per fotòlisi, consum microbià i ventilació. Al capdavall, no sembla que hom pugui definir un patró d’oscil·lació dia-nit únic per al DMS a l’oceà global. L’obtenció de dades en moltes províncies oceàniques tropicals i subtropicals va confirmar que la distribució del DMS s’explica millor amb factors abiòtics tals com la radiació solar, la barreja vertical, l’absorció de la llum per la matèria orgànica, i també per factors de fisiologia de fitoplàncton, com l’eficiència del fotosistema II, més que amb els indicadors d’abundància i activitat general del plàncton. El treball mostra també que les inferències que hom pugui fer sobre les causes de variabilitat de la concentració del DMS depenen força de la freqüència d’observació. En una campanya de circumnavegació, les mesures fetes a baixa freqüència mostraven, per a una província donada, una amplitud de variació d’un factor de 5. En la mateixa província, les mesures d’alta freqüència mostraven una amplitud d’un factor de 96, perquè capturaven la variabilitat de mesoescala i submesoescala. L’anàlisi estadística de les dades d’alta freqüència va mostrar que les distàncies de variabilitat crítiques per al DMS eren de 15 i 50 km per aigües més costaneres i més oceàniques, respectivament. Les distàncies d’heterogeneïtat en la distribució del DMS es fan més curtes amb la latitud i com més productives són les aigües. Això té implicacions importants en el disseny de treball de camp i en els esforços de ‘mapejat’ computacional. En conjunt, la tesi aporta llum a la complexitat de les interaccions que intervenen en el cicle del DMS, i ressalta la dificultat de trobar una relació simple que permeti predir la concentració i emissió del DMS en qualsevol punt de l’oceà global a partir de variables ambientals conegudes.
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Thorkelsdóttir, Hrönn. « Disconnected realities within Icelandic agriculture : A field study of farmers' narratives on the changing landscape of domestic agricultural production in Hrunamannahreppur, Southern Iceland ». Thesis, Stockholms universitet, Kulturgeografiska institutionen, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-182382.
Texte intégralRésumé :
This thesis is situated in the academic sphere of human geography. The overall aim is to identify the current challenges and possibilities Icelandic farmers face in terms of changes in importation laws. This research is exemplary in its field as it uses the narratives of the stakeholders, farmers in this case, as the main data source. The research questions were as following: Is there an agricultural cluster in the region and if so, how does it work; what challenges and possibilities do farmers in the municipality of Hrunamannahreppur face in terms of the recent import law and lastly; according to the farmers, how do policies and laws in Icelandic agriculture ensure long-term farming practices in Iceland. The thesis uses theories of agricultural localization theory, cluster theory and the concepts of competitive and comparative advantages along with the concept of food self-sufficiency. The methods used are semi-structured qualitative interviews during a field study in southern Iceland. Data sources include seven qualitative interviews with farmers in the selected area, a review of agricultural policies and frameworks, and other sources such as articles and media. The main findings are that there is an unexplained disconnect within agriculture and its actors, indicating that policies give preferentiality to economic gain rather than preserving long-term farming in Iceland.
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Miranda, Marina Jorge de. « Análise geográfica de nascimento pré-termo no estado de São Paulo, na RMSP e no município de São Paulo ». Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/8/8135/tde-12112015-164609/.
Texte intégralRésumé :
A prematuridade é um dos grandes problemas de saúde pública, contribuindo com elevados números para a morbi-mortalidade infantil, principalmente em países em desenvolvimento como o Brasil. Conceitua-se o nascido prematuro ou pré-termo como aquele que nasce com menos de 37 semanas de gestação. Os fatores de risco individuais associados à incidência da prematuridade são conhecidos. No entanto, os fatores contextuais que podem influenciar na sua incidência têm sido pouco estudados. Sabe-se que a prematuridade é variável conforme a raça, as condições socioeconômicas, ambientais e culturais em que as mães estão inseridas. Assim, a presente tese teve por objetivo analisar o padrão da distribuição geográfica do risco relativo da prematuridade infantil em diferentes escalas: no estado de São Paulo, na Região Metropolitana de São Paulo e na esfera intra-urbana do município de São Paulo, durante o período de 2002 a 2007 (estado de SP), 2000 a 2010 (RMSP) e 2002 a 2013 (MSP) por meio da análise espacial exploratória. Investigamos como o contexto geográfico tem afetado o risco relativo de nascimentos pré-termo, através de testes de associação espacial global e local (I Moran e LISA) para estado de SP e para RMSP. Pela regressão multivariada global (OLS) e regressão geograficamente ponderada (GWS), estudamos quais variáveis explanatórias tiveram melhor capacidade explicativa para compreender espacialmente os riscos de nascimentos pré-termo no estados de SP (variável dependente). As variáveis explanatórias (independentes) foram representadas: pelas condições socioeconômicas das mães e foram mensuradas pelo índice de privação sociomaterial (IP), assim como pelo acesso ao sistema de saúde materna e do recém-nascido, representados pela porcentagem de cesáreas, pelo número de consultas pré-natal acima de 7 e pelo número de UTIs neonatais por 1000 nascidos vivos. Para isso, utilizamos dados de saúde do Sistema de Nascidos Vivos (SINASC) do Ministério da Saúde (DATASUS), dados socioeconômicos da Fundação SEADE, e dados de acesso da saúde materna e do recém-nascido do Cadastro Nacional de Estabelecimentos de Saúde (CNEs). Tanto os riscos relativos de nascimentos pré-termo como as variáveis socioeconômicas apresentaram autocorrelação espacial global significativa. Houve associação espacial local significativa entre os riscos relativos de nascidos prematuros com todas as variáveis socioeconômicas testadas para o estado de SP e para RMSP. As distribuições geográficas destas associações ocorreram de maneira não aleatória e heterogênea pelo estado de SP e pela RMSP, demonstrando a forte e complexa relação entre indicadores de saúde dos recém-nascidos com as condições socioeconômicas em que mães estão inseridas. Apenas o número de UTIs neonatais foi a única variável estatisticamente significativa do modelo global OLS, que melhor explicou a distribuição geográfica dos riscos relativos de nascimentos pré-termo no estado de SP. O modelo GWR ajudou a identificar separadamente e localmente quais os munícipios do território paulista que apresentaram riscos mais altos de nascimentos pré-termo pela privação sócio-material, pela porcentagem de cesáreas, pela porcentagem de consultas pré-natal acima de 7 e pelo número de UTIs neonatais por 1000 nascidos vivos.Prematurity is a serious public health issue, increasing significantly the child morbidity and mortality cases, especially in developing countries such as Brazil. A premature or preterm birth is defined when the birth occurs with less than 37 gestational weeks. While the individual risk factors associated with the incidence of prematurity are known, contextual factors able to impact it have not been given the same attention. It is known that prematurity is influenced by the ethnic group and socio-economic, environmental and cultural conditions experienced by the mother. In this context, the present thesis aimed to analyze the spatial distribution patterns of the relative risk of premature birth, through exploratory spatial data analysis, in three different spatial scales: the state of São Paulo (SP), the São Paulo Metropolitan Area (SPMA), and in the intra-urban scale of the municipality of São Paulo (SPM). The time period studied ranged from 2002 to 2007 (SP), 2000 to 2010 (SPMA) and 2002 to 2013 (SPM). We investigated how the geographical context has affected the relative risk of preterm birth through global and local spatial association tests (Morans I and LISA) for the state of SP and the SPMA. Using the global multivariate regression (OLS) and the geographically weighted regression (GWR), we studied which explanatory variables best explained, spatially, the risk of preterm birth in the state of SP (dependent variable). The explanatory variables (independent) were represented by the socioeconomic conditions of the mothers and were measured by the sociospatial deprivation index (DPi), as well as the health system access by the mothers and premature infants, represented by the number of caesarian deliveries, number of prenatal testings above 7 and number of newborn emergency entries by 1000 live births. For that, we used data from the national Live Birth System (SINASC) from the Ministry of Health (DATASUS), socioeconomic data from the SEADE foundation, and newborn and maternal health access data from the National Registry of Health Facilities (CNEs) from Brazil. Both the preterm birth relative risks and the socioeconomic variables presented significant global spatial autocorrelation. There was significant spatial local association between the premature birth relative risks with all socioeconomic variables tested for the state of SP and for the SPMA. The geographical distribution of such associations occurred in a non-random pattern, and heterogeneously distributed through the territory of the state of SP and the SPMA, revealing the strong and complex relation between the newborn health indicators and the socioeconomic conditions to which their mothers are subject. The number of emergency entries was the statistically significant variable form the global model that best explained the geographical distribution of the preterm birth relative risks in the state of SP. The GWR helped to identify locally which municipalities of the state presented higher risks of preterm birth due to the sociospatial deprivation index, the number of caesarian deliveries, number of prenatal testings above 7 and number of newborn emergency entries by 1000 live births.