Tesis sobre el tema "Long-term persistence"
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Valencia, Caicedo Felipe. "Three essays in long-term economic persistence". Doctoral thesis, Universitat Pompeu Fabra, 2015. http://hdl.handle.net/10803/297566.
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This dissertation investigates economic persistence in the Americas. The first chapter
shows the positive long-term economic impact of the Guarani Jesuit Missions in
South America. I find that municipalities in Argentina, Paraguay and Brazil with former
missionary presence have higher educational and income levels today. Such enduring
differences are consistent with cultural transmission mechanisms. The second chapter
establishes the within country persistence of economic activity in the New World over
the last half millennium. In particular, we show that high pre-colonial density areas
tend to be denser today. Furthermore, we document that these historically prosperous
areas also tend to have higher incomes today, largely due to agglomeration effects. The
third and final chapter argues that differences in innovative capacity, captured by the
density of engineers at the dawn of the Second Industrial Revolution, are important to
explaining present income differences between Latin and North America, and within
the United StatesEsta disertación trata sobre persistencia económica en las Américas. El primer capítulo muestra el impacto positivo a largo plazo de las Misiones Jesuitas Guaraníes en Suramérica. Encuentra que las municipalidades en Argentina, Paraguay y Brasil que tuvieron presencia misionera tienen hoy mayores niveles de educación e ingreso. Estas diferencias son consistentes con mecanismos de transmisión cultural. El segundo capítulo establece la persistencia de la actividad económica en el Nuevo Mundo durante los últimos 500 años. Específicamente, demuestra que las áreas con mayor densidad de población pre-colonial son más densamente pobladas ahora. Además muestra que estas áreas históricamente prósperas también tienen mayores ingresos hoy, debido a efectos de aglomeración. El tercer y último capítulo argumenta que las diferencias en capacidad de innovación, medidas utilizando la densidad de ingenieros durante la Segunda Revolución Industrial, son importantes para explicar las diferencias de ingreso entre Latinoamérica y Norteamérica, así como dentro de los Estados Unidos.
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Thyer, Mark Andrew. "Modelling long-term persistence in hydrological time series". Diss., 2000, 2000. http://www.newcastle.edu.au/services/library/adt/public/adt-NNCU20020531.035349/index.html.
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McLaren, Jack. "Adult students in university : long-term persistence to degree-completion". Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/31101.
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Long-term persistence to degree completion by adult university students represents a different focus from most adult education participation research and higher education dropout research. Much of the research on adults in university has treated these adults as a new (non-traditional) group, despite evidence that many had been enrolled as traditional-age students. Samples limited to first-year students, part-time students, and students in special programs provide only a limited perspective on the whole population of adults in university.
It was hypothesized that adults who had been in university as traditional-age students and returned later (Re-entry studenty) would be more persistent to degree completion than adults who had enrolled for the first time at age twenty-five or older (Adult Entry students). While the hypothesis was not clearly supported, differences between the two groups were discovered.
Six hypotheses were generated from the literature on adult participation and on higher education dropouts. These were tested using bivariate analysis. The multivariate techniques of multiple regression and discriminant analysis were employed to examine differences between Re-entry students and Adult Entry students in persistence to degree completion.
The most important variable affecting Re-entry-students' persistence was Grade Point Average; the most potent variable with Adult Entry students was work-related problems. With both groups, persistence was affected by satisfaction. Early-career mobility had an ambiguous
effect; downward mobility in early career was associated with persistence by Adult Entry students; upward mobility correlated with persistence by Re-entry students.
A new typology of adult student in higher education is suggested. First-time students—new students who have never previously been enrolled—are a high-risk group (prone to dropout), but those who persist initially may become more persistent than Re-entry students.Education, Faculty of
Educational Studies (EDST), Department of
Graduate
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Strimas-Mackey, Matthew. "Accounting for long-term persistence of multiple species in systematic conservation planning". Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/58572.
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Protected areas form the cornerstone of global efforts to conserve biodiversity. The goal of systematic conservation planning is to design protected area networks that secure the long term persistence of biodiversity. However, most current methods focus on maximizing the representation of species and don’t explicitly plan for the persistence of those species in the protected landscapes into the future. In this thesis, I present a new tool for systematic reserve design that optimizes the configuration of reserve networks to maximize persistence across multiple species. This method is based on metapopulation capacity, a relative, asymptotic metric of persistence derived from a spatially explicit metapopulation model. This metric requires few parameters to calculate, and incorporates the size and spatial configuration of reserves as well as species-specific dispersal dynamics among them. I demonstrate this method using a case study in Indonesian New Guinea with 114 terrestrial mammal species. Compared to Marxan, the most popular representation-based reserve design tool, my persistence-based method led to a 2.3-times increase in mean metapopulation capacity across all species. At the level of individual species, I identified two distinct groups: those that experienced significant benefits from the persistence-based approach and those for which the Marxan solution was nearly as good or slightly better. This thesis demonstrates that systematic reserve design can account for species persistence in an ecologically meaningful way, and that this approach can yield significant gains compared to traditional methods.Science, Faculty of
Zoology, Department of
Graduate
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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.
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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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Li, Bocheng. "Influence of Petroleum Deposit Geometry on Long Term Persistence of Residual Crude Oil". Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/54007.
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Following the DWH oil spill event, crude oil reaching the shoreline of Gulf of Mexico produced petroleum oil deposit with a range of distinct geometries, including sphere tar balls and horizontal tar sheets. Numerical models were developed based on the Deep Water Horizon oil spill conditions to evaluate the influence of deposit geometry on long term persistence of residual NAPL oil. Two extreme deposit geometries were modeled in this study: the horizontal tar sheet and the spherical tar ball. Both two-dimensional modeling approach and three-dimensional modeling approach were applied to compare two contrasting geometries. The two-dimensional model results showed that sheet geometry deposits exhibited a greater obstruction to groundwater flow relative to the spherical deposits and induced a larger sulfate reducing zone downgradient of the NAPL source, resulting in significantly greater sulfate-based biodegradation of benzene. Three-dimensional models were constructed to assess the influence of key geometry parameters on oil deposit fate and persistence. Three parameters affecting deposit's geometric structure were recognized, including the upper horizontal area of the sheet deposit, the thickness of the sheet deposit, and the radius of the sphere deposit. The three-dimensional model results suggested that thickness of the sheet deposit and radius of the sphere deposit were important geometry factors impacting the fate and long term persistence of residual NAPL oil in the coastal environment. However, the influence of deposit geometry differed depending on the solubility of the different NAPL components. When high solubility compound and low solubility compound both exist in the oil deposit, the influence of deposit geometry on benzene degradation was significant, while the influence on naphthalene was almost negligible.Master of Science
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Yenni, Glenda Marie. "Self-limitation as an explanation for species' relative abundances and the long-term persistence of rare species". DigitalCommons@USU, 2013. https://digitalcommons.usu.edu/etd/1958.
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Much of ecological theory describes species interactions. These interactions often play an important theoretical role in facilitating coexistence. In particular, rarity in ecological communities, though often observed, provides a significant challenge to theoretical and empirical ecologists alike. I use a plant community model to simulate the effect of stronger negative frequency dependence on the long-term persistence of the rare species in a simulated community. This strong self-limitation produces long persistence times for the rare competitor, which otherwise succumb quickly to stochastic extinction. The results suggest that the mechanism causing species to be rare in this case is the same mechanism allowing those species to persist. To determine if ecological communities generally show the theoretical pattern, I estimate the strength of frequency-dependent population dynamics using species abundance data from 90 communities across a broad range of environments and taxonomic groups. In approximately half of the analyzed communities, rare species showed disproportionately strong negative frequency dependence. In particular, a pattern of increasing frequency dependence with decreasing relative abundance was seen in these communities, signaling the importance of this mechanism for rare species specifically. Insight into the special population dynamics of rare species will inform conservation efforts in response to climate change and other disturbance. Further difficulties in the detection of theoretical patterns in ecological data may be a result of the ecological currency used. Though ecologists typically use abundance data to test theories, energy use is another ecological currency that may be more relevant in some cases. In particular when detecting patterns that are a result of species interactions, the currency used should be the one in which those interactions actually operate. I compare the results of using abundance and energy use to detect two processes with well-defined expectations. The first is a description of population dynamics, the above described relationship between relative abundance and self-limitation. The second, compensatory dynamics, is a description of community-level dynamics. I find that the currency used alters the results, and thus the species-level implications. It does not, however, alter the overall pattern that would have theoretical implications. Results in both currencies support the pattern of strong self-limitation for persistent rare species.
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Manzello, Derek Paul. "Short and Long-term Ramifications of Climate Change upon Coral Reef Ecosystems: Case Studies Across Two Oceans". Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_dissertations/78.
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World-wide coral reefs are in a state of decline as a result of many local and regional factors. Recent global mass mortalities of reef corals due to record warm sea temperatures have led researchers to consider global warming as one of the most significant threats to the persistence of coral reef ecosystems over the next 100 years. It is well established that elevated sea surface temperatures (SSTs) cause widespread coral bleaching, yet confusion lingers as to what facet of extreme temperatures is most important. Utilizing long-term in situ datasets, nine thermal stress indices were calculated and their effectiveness at segregating bleaching years a posteriori for multiple reefs on the Florida Reef Tract was tested. Simple bleaching thresholds based on deviations above the climatological maximum monthly SST were just as effective at identifying bleaching years as complex thermal stress indices. Near real-time bleaching alerts issued by NOAA's Integrated Coral Observing Network (ICON) are now based upon a running 30-day average SST, such that alerts are only issued when the running 30-day average SST exceeds the estimated bleaching threshold for a particular site. In addition to three widespread, mass-coral bleaching events, the Florida Reef Tract was impacted by three tropical storms and 12 hurricanes from 1997-2005. Sea surface cooling associated with the high frequency of hurricanes that impacted Florida in 2005 likely acted to ameliorate the severity and duration of bleaching. Nonetheless, hurricane-associated cooling is not expected to nullify the proposed effects of climate change on coral reefs. The role of thermal stress in coral bleaching has been extensively studied for eastern tropical Pacific (ETP) coral reefs. However, the ETP presents a unique opportunity as this region has sub-optimal conditions for coral reef development because of upwelling of carbon dioxide-enriched deep water along the shallow thermocline. This upwelling results in a depressed aragonite saturation state which is likely an additional factor in the poor reef development throughout the ETP. The highest aragonite saturation documented in this study occur in the Gulf of Chiriquí, which corresponds with the greatest reef development of the entire ETP. Seasonal upwelling had a significant effect on the carbonate chemistry of surface waters in Pacific Panamá. This regionally-depressed aragonite saturation state of the ETP appears to result in corals with a less dense skeleton. Density values of poritid corals from the Galápagos, where aragonite saturation was the lowest documented in this study, were significantly less dense relative to those from Panamá and the Great Barrier Reef. The density of non-living pocilloporid framework components were no different across the ETP aragonite saturation gradients. This could be a result of the activity of boring sponges removing the primary carbonate material within the dead coral skeleton, thus lowering density, albeit physical-chemical dissolution cannot be ruled out. These studies provide real-world examples of the ramifications of global climate change upon coral reef ecosystems.
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Wood, David. "Forest Disturbance and the Long Term Population Persistence of the Mt. Graham Red Squirrel: A Spatially Explicit Modeling Approach". Thesis, The University of Arizona, 2007. http://hdl.handle.net/10150/193362.
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We combined field data with high-resolution satellite imagery and a spatially explicit population model to predict long-term population dynamics of the endangered Mt. Graham red squirrel (MGRS: Tamiasciurus hudsonicus grahamensis), with the goal of examining effects of disturbance on MGRS population dynamics. We found that modeling MGRS dynamics improved with population specific data. Our results indicate that predation and competition potentially have large, adverse effects on population abundance. Habitat quality analysis indicates much of the spruce-fir forest is degraded to the point that it cannot support MGRS, therefore, the future of the species will rely on management in the mixed conifer zones. Our models predict that future populations will not show the variability exhibited in abundance over the past 20 years, likely due to degradation of spruce-fir forests, and that even low levels of fire and insect disturbance have the potential to drive MGRS population below critical population thresholds.
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Carossino, Mariano. "CELLULAR AND MOLECULAR BASIS OF EQUINE ARTERITIS VIRUS PERSISTENT INFECTION IN THE STALLION REPRODUCTIVE TRACT: CHARACTERIZATION OF LOCAL HOST-PATHOGEN INTERACTIONS MEDIATING LONG-TERM VIRAL PERSISTENCE". UKnowledge, 2018. https://uknowledge.uky.edu/gluck_etds/35.
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Equine arteritis virus (EAV) has a global impact on the equine industry being the causative agent of equine viral arteritis (EVA), a reproductive, respiratory, and systemic disease of equids. A distinctive feature of EAV infection is that it establishes long-term persistent infection in the reproductive tract of stallions and is continuously shed in the semen (carrier state). Recent studies showed that long-term persistence is associated with a specific allele of the CXCL16 gene (CXCL16S). However, the cellular and molecular mechanisms underlying the establishment and maintenance of persistent infection are yet to be determined. The studies were undertaken herein unequivocally demonstrated that the ampulla is the main EAV tissue reservoir rather than immunologically privileged tissues (i.e., testes) and that EAV has specific tropism for stromal cells and CD8+ T and CD21+ B lymphocytes but not glandular epithelium in the reproductive tract. Furthermore, persistent EAV infection is associated with a significant humoral, mucosal antibody and inflammatory response at the site of persistence, characterized by induction of high levels of neutralizing antibodies (IgG1), mucosal anti-EAV-specific IgA, IgG1, IgG3/5, and IgG4/7 with variable neutralizing efficacy; and moderate, multifocal lymphoplasmacytic ampullitis, with significant infiltration of T lymphocytes (mainly CD8+ and low numbers of FOXP3+ lymphocytes), CD21+ B lymphocytes, diverse Ig-secreting plasma cells, and Iba-1+ and CD83+ tissue macrophages/dendritic cells. Moreover, EAV long-term persistent infection is associated with a CD8+ T lymphocyte transcriptional profile with upregulation of T-cell exhaustion-related transcripts and homing chemokines/chemokine receptors (CXCL9-11/CXCR3 and CXCL16/CXCR6), orchestrated by a specific subset of transcription factors (EOMES, PRDM1, BATF, NFATC2, STAT1, IRF1, TBX21), which are associated with the presence of the susceptibility allele (CXCL16S). Finally, these studies have determined that long-term EAV persistence is associated with the downregulation of a specific seminal exosome-associated miRNA (eca-mir-128) along with an enhanced expression of CXCL16 in the reproductive tract, a putative target of eca-mir-128. These findings provide evidence that this miRNA plays a crucial role in the regulation of the CXCL16/CXCR6 axis in the reproductive tract of persistently infected stallions, a chemokine axis strongly implicated in EAV persistence. The findings presented herein suggest that complex host-pathogen interactions shape the outcome of EAV infection in the stallion and that EAV employs complex immune evasion mechanisms favoring persistence in the reproductive tract. Further studies to identify specific mechanisms mediating the modulation of the CXCL16/CXCR6 axis and viral immune evasion in the reproductive tract of the EAV long-term carrier stallion are warranted.
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Pisa, Martín Sergio. "Long distance dispersal, local adptation and long term persistence in bryophytes : studies in the moss Bryum argenteum= Dispersión a larga distancia, adaptación local y persistencia a largo plazo en briófitos: estudios en el musgo Bryum argenteum". Doctoral thesis, Universidad de Murcia, 2015. http://hdl.handle.net/10803/326746.
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Los briófitos, en comparación con las plantas con semilla, se dispersan a mayores distancias, tienen mayor amplitud ecológica, menos endemismos y distribuciones geográficas más amplias. Dos hipótesis se han discutido tradicionalmente para explicar sus amplias y disyuntas distribuciones. La primera lo interpreta como resultado de la fragmentación de una antigua distribución continua (vicarianza). La segunda lo explica como consecuencia de la dispersión intercontinental. En general, los estudios genéticos sugieren que ha habido dispersión intercontinental durante la diversificación de briófitos, pero no la suficiente como para evitar la diferenciación alopátrica. Los briófitos cosmopolitas exhiben una baja, quizás insignificante, estructura filogeográfica entre continentes, apoyando la hipótesis de dispersión sobre la de vicarianza. Esto hace preguntarse si la dispersión es ubicua y los variantes de una determinada especie cosmopolita se distribuyen homogéneamente. El principio de Baas Becking postula que "todo está en todas partes, pero el ambiente selecciona”. Las características de los briófitos cosmopolitas los hacen candidatos ideales para probar el principio de Baas Becking, aunque estos no han sido testados, hasta ahora. Por otro lado, si se encontraran límites a la dispersión y por tanto se rechazara la hipótesis del principio de Baas Becking, los briófitos cosmopolitas podrían haber logrado su distribución global ayudados por actividades humanas. Esta hipótesis podría verse reforzada por su afinidad a hábitats perturbados, que recuerda el comportamiento de especies invasoras. Esta tesis aborda diferentes hipótesis concernientes a la ecología, distribución, historia y potencial invasivo de plantas con capacidad para dispersarse a larga distancia y más en concreto, de briófitos cosmopolitas, usando Bryum argenteum como especie modelo. En particular, esta tesis trata del principio de Baas Becking tanto a escala mundial como local, en las montañas de Sierra Nevada (España) y la isla de Tenerife. Además, otras hipótesis fueron testadas en base a los resultados preliminares incluyendo la reciente colonización o la persistencia in situ de B. argenteum en el continente Antártico y discernir si colonizó Tenerife de forma artificial o natural. La metodología aplicada incluye el uso de secuencias genéticas de numerosas muestras recolectadas en Sierra Nevada, Tenerife y en todas las masas continentales. Las secuencias fueron analizadas con técnicas de genética de poblaciones y filogeografía incluyendo análisis comparativos, estimadores de diversidad genética, tests de correlación (tests de Mantel), estimadores de estructura genética entre poblaciones, reconstrucciones de áreas ancestrales, datación de reloj molecular y tests de neutralidad. Las conclusiones generales de esta tesis son: • Las evidencias en Sierra Nevada apoyan la primera mitad de la hipótesis de Baas Becking “Todo está en todas partes” a escala local. Por el contrario, la estructura genética en Tenerife sugiere que la deriva génica juega también un papel en el establecimiento de los patrones de variación genética. • El medio ambiente impulsa la diferenciación genética tanto en Sierra Nevada como en Tenerife, apoyando la segunda mitad del principio de Baas Becking “el ambiente selecciona” a escala local. Así que los briófitos cosmopolitas podrían formar ecotipos. • El factor clave que explica la distribución genética mundial de B. argenteum es la dispersión intercontinental recurrente. Sin embargo, la dispersión no es ubicua y por tanto, se rechaza la hipótesis del principio de Baas Becking a escala global. • La Antártida está mucho más aislada en términos de dispersión de briófitos que cualquier otro continente. • B. argenteum colonizó la Antártida al menos en tres ocasiones persistiendo en el continente durante varios ciclos glaciales. En Sierra Nevada, la especie se mantuvo en una zona glaciar durante el pleistoceno tardío. • B. argenteum colonizó la isla de Tenerife en múltiples ocasiones. Las primeras colonizaciones tuvieron lugar mucho antes de los primeros asentamientos humanos.The bryophytes, in contrast with seed plants, are capable to disperse over longer distances, have broader ecological amplitudes, less endemism and wider geographical distributions. Two hypotheses have been traditionally discussed to explain their broad and disjunctive geographical distributions. The first hypothesis interprets it as a result of fragmentation of ancient continuous distributions (i.e. vicariance). The second explains it as a consequence of intercontinental dispersal. In general, genetic studies suggest that dispersal among continents has occurred repeatedly during bryophyte diversification, although it has not been recurrent enough to prevent allopatric differentiation. Research on cosmopolitan bryophytes indicates that they exhibit a low, potentially negligible, structure among continents favouring the long distance dispersal hypothesis over vicariance. This raises the question of whether dispersal is ubiquitous and the variants of cosmopolitan species are distributed everywhere. The Baas Becking tenet posits that ‘everything is everywhere, but the environment selects’ (EiE). The peculiar characteristics of cosmopolitan bryophytes suggest that they are ideal candidates to test the EiE tenet, yet they remained untested until now. On the other hand, if there were limits to dispersal at a global scale and, thus, the EiE hypothesis would be rejected, cosmopolitan bryophytes might have achieved their global distribution aided by anthropogenic activities. This hypothesis might be reinforced by the affinity of cosmopolitan bryophytes to disturbed habitats, which is reminiscent of invasive species’ behaviour. This thesis addresses a variety of hypothesis regarding the ecology, distribution, history and potential invasiveness of vagile plants and more specifically, of cosmopolitan bryophytes, taking the moss Bryum argenteum as a model species. In particular, this thesis deals with the EiE tenet at global scale and locally on the Sierra Nevada Mountains (Spain) and on the island of Tenerife. Additionally, based on preliminary findings, further hypotheses were tested including the recent colonization or in situ persistence of the species in the Antarctic continent and the assessment of the potential alien status of B. argenteum on Tenerife. The methodology applied includes the use of genetic sequences from numerous accessions sampled from Spanish Sierra Nevada Mountains, the island of Tenerife and from each of the continental masses on Earth. The DNA sequences were analysed with statistical techniques from the fields of population genetics, and phylogeography such as comparative analyses, genetic diversity estimators, correlation tests (Mantel tests), estimators of genetic differentiation, ancestral areas reconstructions, molecular dating and tests of neutrality. The main conclusions of this thesis are: • Evidence in Sierra Nevada Mountains supports the first half of the EiE tenet “Everything is everywhere” at a local scale. On the contrary, the spatial genetic structure found in Tenerife suggests that genetic drift plays also a role in establishing patterns of genetic variation. • Evidence for an environmentally-driven pattern of genetic differentiation in both, Sierra Nevada and Tenerife, indicates that the second half of the EiE tenet, “the environment selects” applies at a local scale in B. argenteum. Therefore, cosmopolitan bryophytes may form ecotypes. • Recurrent intercontinental dispersal is the key factor that explains the worldwide genetic distribution of B. argenteum. However, dispersal is not ubiquitous but limited. Thus, the EiE tenet is rejected at a global scale. • The Antarctic continent is by far the most isolated continent of all in terms of bryophyte dispersal. • B. argenteum colonized the Antarctica on at least three occasions and successfully persisted in the continent during several glacial cycles. Evidence in Sierra Nevada suggests long term persistence in a range that was glaciated during the late Pleistocene. • B. argenteum colonized the island of Tenerife on multiple occasions. Earlier events of colonization on the island took place well before the first human settlements.
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Griffiths, Mat. "A thesis on the clinical behhaviour, histological features, long term persistence and cytokine profile of a living skin substitute in an acute, deep-dermal, human wound model". Thesis, Queen Mary, University of London, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.542035.
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Signor, Cristiane. "EFEITO DA ESPERMIDINA SOBRE A PERSISTÊNCIA DA MEMÓRIA EM RATOS". Universidade Federal de Santa Maria, 2013. http://repositorio.ufsm.br/handle/1/11211.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorThe long-term memory involves three stages: acquisition, consolidation and extinction. However was recently described a new phase of consolidation, called the persistence of memory. At this stage, crucial events occur 12 hours after the acquisition, in which the synthesis of new proteins and brain derived neurotrophic factor, are essential. The polyamines putrescine, spermidine and spermine, they act as endogenous modulators of various ion channels, including the glutamatergic receptor subtype N-methyl-D-aspartate. Systemic and intra-cerebral spermidine, immediately after training, improves memory in various tasks in rats. However, no studies demonstrating the effect of spermidine on the persistent memory. Thus, we investigated the effect of systemic administration of spermidine, and arcaine, antagonist of polyamine site on the N-methyl-D-aspartate, the persistence of memory, through the task of contextual fear conditioning. For this study, were used adult male Wistar rats, which underwent a training session on the task of contextual fear conditioning, and 12 hours after training, received a systemic administration of spermidine (0.1-30 mg/kg ), arcaine (0.1-10 mg/ kg) or the combination of spermidine and arcaine. In the second or the seventh day after training the mice were tested. Systemic administration of spermidine improved, whereas systemic administration of impaired arcaine the persistence of memory, when the rats were tested in the second and seventh day after training. The arcaine (0.1 mg / kg) in a dose that has no effect per se prevented improved starry induced by spermidine (10 mg/kg), whereas spermidine (1 mg/kg) dose not effect per se has prevented the worsening of starry arcaine induced (10 mg/kg), when the rats were tested in the second and seventh day after training. These results suggest the involvement of spermidine in persistent memory in rats.
A memória de longa duração envolve três fases: aquisição, consolidação e evocação. No entanto, recentemente foi descrita uma nova fase de consolidação, denominada de persistência da memória. Nesta fase, ocorrem eventos cruciais 12 horas após a aquisição, na qual a síntese de novas proteínas e do fator neurotrófico derivado do encéfalo, são essenciais. As poliaminas putrescina, espermidina e espermina, atuam como moduladores endógenos de diversos canais iônicos, incluindo o subtipo de receptor glutamatérgico N-metil-D-aspartato. A administração sistêmica e intra-cerebral de espermidina, imediatamente após o treino, melhora a memória em diversas tarefas em ratos. Entretanto, não há estudos demonstrando o efeito da espermidina sobre a persistência da memória. Assim, nós investigamos o efeito da administração sistêmica de espermidina, e de arcaína, antagonista do sítio das poliaminas no receptor N-metil-D-aspartato, na persistência da memória, através da tarefa de medo condicionado contextual. Para este estudo, foram utilizados ratos Wistar machos adultos, os quais, foram submetidos a uma sessão de treino na tarefa de medo condicionado contextual, e 12 horas após o treinamento, receberam uma administração sistêmica de espermidina (0,1-30 mg/kg), arcaína (0,1-10 mg/kg) ou a associação de espermidina e arcaína. No segundo ou no sétimo dia após o treino os ratos foram submetidos ao teste. A administração sistêmica de espermidina melhorou, enquanto que a administração sistêmica de arcaína prejudicou a persistência da memória, quando os ratos foram testados no segundo e no sétimo dia após o treino. A arcaína (0,1 mg/kg) na dose que não possui efeito per se, preveniu a melhora da persistência da memória induzida pela espermidina (10 mg/kg), enquanto que a espermidina (1 mg/kg) na dose que não possui efeito per se, preveniu a piora da persistência da memória induzida pela arcaína (10 mg/kg), quando os ratos foram testados no segundo e no sétimo dia após o treino. Estes resultados sugerem o envolvimento da espermidina na persistência da memória em ratos.
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Lindeberg, Carola. "Long-term changes of mercury, lead and persistent organic pollutants in arctic environments". Doctoral thesis, Umeå : Department of Ecology and Environmental Science, Umeå Univ, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-1060.
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Lowry, Stephanie Margaret. "Visual place recognition for persistent robot navigation in changing environments". Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/79404/1/Stephanie_Lowry_Thesis.pdf.
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This thesis demonstrates that robots can learn about how the world changes, and can use this information to recognise where they are, even when the appearance of the environment has changed a great deal. The ability to localise in highly dynamic environments using vision only is a key tool for achieving long-term, autonomous navigation in unstructured outdoor environments. The proposed learning algorithms are designed to be unsupervised, and can be generated by the robot online in response to its observations of the world, without requiring information from a human operator or other external source.
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Ehlers, Ina. "NMR studies of metabolites and xenobiotics: From time-points to long-term metabolic regulation". Doctoral thesis, Umeå universitet, Institutionen för medicinsk kemi och biofysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-97684.
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Chemical species carry information in two dimensions, in their concentrations and their isotopic signatures. The concentrations of metabolites or synthetic compounds describe the composition of a chemical or biological system, while isotopic signatures describe processes in the system by their reaction pathways, regulation, and responses to external stimuli. Stable isotopes are unique tracers of these processes because their natural abundances are modulated by isotope effects occurring in physical processes as well as in chemical reactions. Nuclear magnetic resonance (NMR) spectroscopy is a prime technique not only for identification and quantification of small molecules in complex systems but also for measuring intramolecular distribution of stable isotopes in metabolites and other small molecules. In this thesis, we use quantitative NMR in three fields: in food science, environmental pollutant tracing, and plant-climate science. The phospholipid (PL) composition of food samples is of high interest because of their nutritional value and technological properties. However, the analysis of PLs is difficult as they constitute only a small fraction of the total lipid contents in foods. Here, we developed a method to identify PLs and determine their composition in food samples, by combining a liquid-liquid extraction approach for enriching PLs, with specialized 31P,1H-COSY NMR experiments to identify and quantify PLs. Wide-spread pollution with synthetic compounds threatens the environment and human health. However, the fate of pollutants in the environment is often poorly understood. Using quantitative deuterium NMR spectroscopy, we showed for the nitrosamine NDMA and the pesticide DDT how intramolecular distributions (isotopomer patterns) of the heavy hydrogen isotope deuterium reveal mechanistic insight into transformation pathways of pollutants and organic compounds in general. Intramolecular isotope distributions can be used to trace a pollutant’s origin, to understand its environmental transformation pathways and to evaluate remediation approaches. The atmospheric CO2 concentration ([CO2]) is currently rising at an unprecedented rate and plant responses to this increase in [CO2] influence the global carbon cycle and will determine future plant productivity. To investigate long-term plant responses, we developed a method to elucidate metabolic fluxes from intramolecular deuterium distributions of metabolites that can be extracted from historic plant material. We show that the intramolecular deuterium distribution of plant glucose depends on growth [CO2] and reflects the magnitude of photorespiration, an important side reaction of photosynthesis. In historic plant samples, we observe that photorespiration decreased in annual crop plants and natural vegetation over the past century, with no observable acclimation, implying that photosynthesis increased. In tree-ring samples from all continents covering the past 60 – 700 years, we detected a significantly smaller decrease in photorespiration than expected. We conclude that the expected “CO2 fertilization” has occurred but was significantly less pronounced in trees, due to opposing effects. The presented applications show that intramolecular isotope distributions not only provide information about the origin and turnover of compounds but also about metabolic regulation. By extracting isotope distributions from archives of plant material, metabolic information can be obtained retrospectively, which allows studies over decades to millennia, timescales that are inaccessible with manipulation experiments.
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Gao, Helen Guoyi Li. "INCREASED FIBROGENIC PROTEINS FOLLOWING PERSISTENT LOW-GRADE INFLAMMATION IN A RAT MODEL OF LONG-TERM OVERUSE". Master's thesis, Temple University Libraries, 2013. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/238810.
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Biomedical SciencesM.S.
We examined the relationship between grip strength declines and muscle-tendon responses induced by long-term performance of a high-repetition, low-force (HRLF) reaching task in rats. We hypothesized that grip strength declines would correlate with inflammation, fibrosis and degradation in flexor digitorum muscles and tendons. Grip strength declined after training, and further in weeks 18 and 24, in reach limbs of HRLF rats. Flexor digitorum tissues of reach limbs showed low-grade increases in inflammatory cytokines: IL-1beta after training and in week 18, IL-1alpha in week 18, TNF-alpha and IL-6 after training and in week 24, and IL-10 in week 24, with greater increases in tendons than muscles. Similar cytokine increases were detected in serum with HRLF: IL-1alpha and IL-10 in week 18, and TNF-alpha and IL-6 in week 24. Grip strength correlated inversely with IL-6 in muscles, tendons and serum, and TNF-alpha in muscles and serum. Four fibrogenic proteins, TGFB1, CTGF, PDGFab and PDGFbb, and hydroxyproline, a marker of collagen synthesis, increased in serum in HRLF weeks 18 or 24, concomitant with epitendon thickening, increased muscle and tendon TGFB1 and CTGF. A collagenolytic gelatinase, MMP2, increased by week 18 in serum, tendons and muscles of HRLF rats. Grip strength correlated inversely with TGFB1 in muscles, tendons and serum; with CTGF-immunoreactive fibroblasts in tendons; and with MMP2 in tendons and serum. Thus, motor declines correlated with low-grade systemic and musculotendinous inflammation throughout task performance, and increased fibrogenic and degradative proteins with prolonged task performance. Serum TNF-alpha, IL-6, TGFB1, CTGF and MMP2 may serve as serum biomarkers of work-related musculoskeletal disorders, although further studies in humans are needed.
Temple University--Theses
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Maddern, William Paul. "Continuous appearance-based localisation and mapping". Thesis, Queensland University of Technology, 2014. https://eprints.qut.edu.au/65841/2/William_Maddern_Thesis.pdf.
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This thesis presents a novel approach to mobile robot navigation using visual information towards the goal of long-term autonomy. A novel concept of a continuous appearance-based trajectory is proposed in order to solve the limitations of previous robot navigation systems, and two new algorithms for mobile robots, CAT-SLAM and CAT-Graph, are presented and evaluated. These algorithms yield performance exceeding state-of-the-art methods on public benchmark datasets and large-scale real-world environments, and will help enable widespread use of mobile robots in everyday applications.
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Dean, Philip J. "Long-term outcome from mild traumatic brain injury, and the potential neurophysiological underpinnings for persistent post-concussion syndrome". Thesis, University of Surrey, 2015. http://epubs.surrey.ac.uk/807854/.
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The aim of the research presented is to gain a better understanding of the processes underlying the persistent report of somatic, cognitive and affective symptoms (known as post-concussion syndrome, PCS) after a mild brain injury (mTBI), and to elucidate whether there are any replicable biological factors contributing towards this syndrome. The results demonstrate that although PCS-like symptoms are present to a similar degree in the non-head injured population, individuals with mTBI and persistent PCS have significantly worse working memory, attention and information processing speed performance. Individuals who suffer an MTBI but do not report continued PCS perform these cognitive tasks to the same level as non-head injured controls. Following on from this, the research presented evidence that individuals with greater PCS severity had greater white matter damage, and greater attention related activity during cognitive tasks. Metabolic differences were also observed in the prefrontal cortex of individuals with mTBI, with a reduction in creatine suggesting some residual energy impairment in chronic mTBI. Combining the structural, metabolic and functional MRI data, we suggested that the increased attentional regulation observed during cognitive tasks may be compensating for reduced working memory capacity and a variation in white matter transmission caused by the structural and metabolic changes after injury. This compensation may in turn underlie some PCS symptoms such as fatigue, headache and insomnia. Therefore, the research as a whole suggests that there may be a neurophysiological basis for persistent PCS.
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Wannenwetsch, Oliver [Verfasser], Ramin [Akademischer Betreuer] [Gutachter] Yahyapour y Jens [Gutachter] Grabowski. "Long-Term Location-Independent Research Data Dissemination Using Persistent Identifiers / Oliver Wannenwetsch ; Gutachter: Ramin Yahyapour, Jens Grabowski ; Betreuer: Ramin Yahyapour". Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://d-nb.info/1128902540/34.
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Ellis, David Harold. "Silver nanoparticles: the immediate benefits of low bacterial resistance and the long-term risk of persistent stress in mammalian cells". Wright State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=wright1450827524.
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Lindgren, Monica Elissa. "Persistent fatigue in disease-free breast cancer survivors: Evaluating long-term effects of pretreatment depression and cancer-specific avoidance coping". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468288760.
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Briney, Glenna Denise. "Long term effects of day treatment programs for adults with severe and persistent mental illness: Effectiveness measured in rates of recidivism". CSUSB ScholarWorks, 2005. https://scholarworks.lib.csusb.edu/etd-project/2731.
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The purpose of this study was to compare and measure the long term effectiveness of the rehabilitative day treatment program at San Bernardino County's Department of Mental Health. This current study was completed in 2005 and is a follow up study tracking the long term effectiveness of the program.
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Unger, Julia [Verfasser] y Christian [Akademischer Betreuer] Glück. "The Immediate and Long-term Effects of Altered Auditory Feedback (AAF) on the Characteristics of Persistent Developmental Stuttering / Julia Unger. Betreuer: Christian Glück". Heidelberg : Pädagogische Hochschule Heidelberg, 2012. http://d-nb.info/107028579X/34.
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Bogart, Vada S. "The effects of looping on the academic achievement of elementary school students". [Johnson City, Tenn. : East Tennessee State University], 2002. http://etd-submit.etsu.edu/etd/theses/available/etd-0820102-105005/unrestricted/BogartV082302a.pdf.
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Huang, Nuoyu. "Persistent Oral Dyskinesias Induced by Long-term Haloperidol Treatment is Dissociated from Changes in Neostriatal B(max) and Mrna Content for Dopamine D(2) Receptors". Digital Commons @ East Tennessee State University, 1995. https://dc.etsu.edu/etd/2736.
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Due to the presumed associations of dopamine (DA) receptor supersensitivity phenomena in both long-term neuroleptic-treated tardive dyskinetic rats and neonatal 6-hydroxydopamine (n6-OHDA)-lesioned rats, we studied the influence of haloperidol on n6-OHDA-lesioned rats. At 3 days after birth rats received 6-OHDA-HBr (200 $\mu$g, bilateral intracerebroventricularly; desipramine pretreatment, 20 mg/kg, 1h) or vehicle. Two months later haloperidol (1.5/kg/day $\times$ 2 days/week for 4 weeks, then 1.5 mg/kg/day, every day for 10 months) was added to the drinking water. Spontaneous oral activity of intact and n6-OHDA-lesioned rats receiving haloperidol was reached and maintained at significantly higher levels after 15 weeks of haloperidol treatment. Haloperidol treatment produced greater oral activity in n6-OHDA-lesioned rats as compared to intact rats. At 11 months there were 35.8 $\pm$ 4.9 vs. 18.4 $\pm$ 2.1 oral movements in lesioned vs. intact rats receiving haloperidol. This high level of spontaneous oral activity was not attenuated by scopolamine and persisted in the lesioned rats for at least 8 months after haloperidol withdrawal. Reverse transcription polymerase chain reaction (RT-PCR) analysis of alternatively-spliced isoforms of DA D$\sb2$ (D$\sb{\rm 2S}$ and D$\sb{\rm 2L}$) receptors showed that D$\sb{\rm 2L}$ receptor mRNA levels of intact and n6-OHDA-lesioned rats receiving haloperidol were significantly elevated after 11 months of treatment and returned to normal level 8 months after haloperidol withdrawal. Similarly, the B$\sb{\rm max}$ for $\rm\lbrack\sp3 H\rbrack$raclopride binding to striatal homogenates was significantly increased in intact and nG-OHDA lesioned rats receiving chronic haloperidol. The B$\sb{\rm max}$ was at the control level after 8 months of haloperidol cessation. D$\sb{\rm 2L}$ and 5-HT$\sb{\rm 2C}$ receptor mRNA levels were not altered by chronic haloperidol treatment. The effects of assorted receptor-specific drugs on oral activity were tested in our rats to study possible mechanisms underlying the regulation of oral activity. The findings of this study demonstrate that alterations at mRNA and receptor levels of DA D$\sb2$ receptors are not critical for maintaining persisting enhanced oral dyskinesias after long-term haloperidol treatment. The long-lasting stable high frequency of oral dyskinesias after haloperidol withdrawal in these rats provides a means for testing agents that have the potential to attenuate dyskinetic oral activity.
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Diaz, Sacristan Adria y Marina Tofan. "Upplevelsen av bemötande inom vården hos patienter med kronisk smärta". Thesis, Högskolan i Borås, Akademin för vård, arbetsliv och välfärd, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-21393.
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Kronisk smärta är ett samhällsproblem med stor påverkan på människors liv och som innebär höga kostnader för vården. Tillståndet skapar frustration för både patienter och vårdpersonal på grund av att det saknas effektiv behandling och det är svårt att förklara smärtans uppkomst om ingen somatisk diagnos finns. Detta ledder till att patienterna blir misstrodda och nonchalerade eller sedda som fuskare som vill utnyttja välfärden. Många blir misstänkta för drogberoende och empati saknas i möten med vården. Som en konsekvens tappar patienterna tillit till vården och undviker till och med att söka vård överhuvudtaget. Syftet med denna studie var att beskriva upplevelsen av bemötande inom vården hos patienter med kronisk smärta. Tio vetenskapliga artiklar inkluderades och analyserades efter en noggrann och strukturerad litteratursökning. Ett nytt resultat tog form som indelades i tre huvudkategorier: kronisk smärta - en otillfredsställande diagnos, att bli misstrodd samt att bli lyssnad till och bekräftad. Resultatet diskuterades sedan i relation till annan forskning. Denna studie skulle på ett enkelt sätt kunna tillgodogöras av vårdpersonal och i en förlängning kunna bidra till ökad förståelse för vilka faktorer som underlättar en god vård för patienter med kronisk smärta.
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Thyer, Mark Andrew. "Modelling Long-Term Persistence in Hydrological Time Series". Thesis, 2001. http://hdl.handle.net/1959.13/24891.
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The hidden state Markov (HSM) model is introduced as a new conceptual framework for modelling long-term persistence in hydrological time series. Unlike the stochastic models currently used, the conceptual basis of the HSM model can be related to the physical processes that influence long-term hydrological time series in the Australian climatic regime. A Bayesian approach was used for model calibration. This enabled rigourous evaluation of parameter uncertainty, which proved crucial for the interpretation of the results. Applying the single site HSM model to rainfall data from selected Australian capital cities provided some revealing insights. In eastern Australia, where there is a significant influence from the tropical Pacific weather systems, the results showed a weak wet and medium dry state persistence was likely to exist. In southern Australia the results were inconclusive. However, they suggested a weak wet and strong dry persistence structure may exist, possibly due to the infrequent incursion of tropical weather systems in southern Australia. This led to the postulate that the tropical weather systems are the primary cause of two-state long-term persistence. The single and multi-site HSM model results for the Warragamba catchment rainfall data supported this hypothesis. A strong two-state persistence structure was likely to exist in the rainfall regime of this important water supply catchment. In contrast, the single and multi-site results for the Williams River catchment rainfall data were inconsistent. This illustrates further work is required to understand the application of the HSM model. Comparisons with the lag-one autoregressive [AR(1)] model showed that it was not able to reproduce the same long-term persistence as the HSM model. However, with record lengths typical of real data the difference between the two approaches was not statistically significant. Nevertheless, it was concluded that the HSM model provides a conceptually richer framework than the AR(1) model.PhD Doctorate
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Thyer, Mark Andrew. "Modelling Long-Term Persistence in Hydrological Time Series". 2001. http://hdl.handle.net/1959.13/24891.
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The hidden state Markov (HSM) model is introduced as a new conceptual framework for modelling long-term persistence in hydrological time series. Unlike the stochastic models currently used, the conceptual basis of the HSM model can be related to the physical processes that influence long-term hydrological time series in the Australian climatic regime. A Bayesian approach was used for model calibration. This enabled rigourous evaluation of parameter uncertainty, which proved crucial for the interpretation of the results. Applying the single site HSM model to rainfall data from selected Australian capital cities provided some revealing insights. In eastern Australia, where there is a significant influence from the tropical Pacific weather systems, the results showed a weak wet and medium dry state persistence was likely to exist. In southern Australia the results were inconclusive. However, they suggested a weak wet and strong dry persistence structure may exist, possibly due to the infrequent incursion of tropical weather systems in southern Australia. This led to the postulate that the tropical weather systems are the primary cause of two-state long-term persistence. The single and multi-site HSM model results for the Warragamba catchment rainfall data supported this hypothesis. A strong two-state persistence structure was likely to exist in the rainfall regime of this important water supply catchment. In contrast, the single and multi-site results for the Williams River catchment rainfall data were inconsistent. This illustrates further work is required to understand the application of the HSM model. Comparisons with the lag-one autoregressive [AR(1)] model showed that it was not able to reproduce the same long-term persistence as the HSM model. However, with record lengths typical of real data the difference between the two approaches was not statistically significant. Nevertheless, it was concluded that the HSM model provides a conceptually richer framework than the AR(1) model.PhD Doctorate
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NanyuWang y 王南喻. "A Study of Long-term & Short-term Persistence of Stock Mutual Funds Performance". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/67677278836165334018.
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碩士國立彰化師範大學
商業教育學系
93
Abstract The purpose of this study was to examine the long-term & short-term persistence of stock mutual funds performance in the United States from 1985 to 2004. The data are collected from The Value Line Mutual Fund Survey database. There are five categories for stock mutual funds based on the The Value Line Mutual Fund Survey database, including Aggressive Growth, Growth, Growth/Income, Income, and Small Company. This study used time-series regression model to observe fund managers’ operating ability over last 20 years, and broke 20 years into two stages: stage one (1985 to 1994) and stage two (1995 to 2004). The empirical evidence showed that there was long-term persistence of fund performance for Aggressive Growth, Growth, Growth/ Income , and Income stock mutual funds respectively. In addition, the short-term persistence of stock mutual fund performance also supported our hypotheses. In other words, there were significances on short-term persistence of Small Company mutual fund performance in every one-year, every two-year, three-year , four-year five-year six-year seven-year eight-year, and nine-year period.
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Huang, chang-hong y 黃全宏. "The Research Of Earnings Persistence Of Long-term Stock Investment Income And Market Efficiency". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/85874963378238147800.
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碩士國立臺灣大學
會計學研究所
89
Abstract Title ：The Research Of Earnings Persistence Of Long-term Stock Investment Income And Market Efficiency University：Graduate Institute Of Accounting Nation Taiwan University Adviser：Tsai，Yann-Ching，Ph.D Name：Huang，Chang-Hong Graduate Date：June，2001 The purpose of this study is to investigate whether long-term stock investment income（accounted for by equity method）has earnings persistence，and whether stock price fully reflects the implication of the information.Efficient market theory requires that investors respond to public information correctly and completely. The samle consists of 340 firm-year from company listed in Taiwan Stock exchange Corporation from 1995 to 1999. The main empirical results are presented as follows： 1、long-term stock investment income has earnings persistence，a little lower than that of operating income，higher than non —operating income’s earnings persistence. 2、Market efficiently impounds the implication of the earnings persistence of long-term stock investment income. 3、Investment income from non-public subsidiary has higher earnings persistence than that from public subsidiary.
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Chang, Chia-Lun y 張家綸. "Family Involvement on the Long-term Performance---the Strategic Persistence and its Mediating Effects". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/74438841730090634671.
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碩士國立成功大學
高階管理碩士在職專班
95
Family firm business in global economic activity has been playing a very important role, but few studies have been to demonstrate connections among family involvement, strategic persistence, and performance. Therefore, this study will focus on examining the following issues. How does family involvement, especially when family members as board directors, affect firm’s long-term performance? Whether the strategic persistence is positive or negative relation with long-term performance? Can the strategic persistence be considering as a mediator between family involvement and long-term performance? In this study, we collected for a sample of 453 companies, all of which were listed on the TSE from 1996 to 2005. As results, first, as we found, the relationship between family involvement and firm’s long-term performance or strategic persistence were negative which means the high proportion of family members as board directors actually has negative consequence to the strategic persistence, as well as to the long-term financial performance. Furthermore, the findings imply strategic persistence can mediate the relationship of the family involvement and firm’s long-term performance.
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Levac, Joshua. "Long-term stand dynamics of the boreal mixed-wood forests of west-central Manitoba". 2012. http://hdl.handle.net/1993/5234.
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To understand the temporal dynamics of a forest, long-term direct observations are required. My study examined the long-term persistence of trembling aspen (Populus tremuloides Michx) and white spruce (Picea glauca (Moench) Voss) in the boreal mixed-wood forests of Riding Mountain National Park. A set of 266, disturbance-free, permanent sample plots were established in 1947 (stand age = 120 years) and followed through time for 55 years. My results indicate that although the density and basal areas of aspen do decline over the 55-year period, a successful regeneration and establishment occurs around 140 years. The long-term persistence of aspen is a result of clonal reproduction following the canopy breakup beginning around 130 years or earlier. This implies that the long-term persistence of both aspen and spruce occur and the expected succession to softwood dominance does not occur.
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Fraterrigo, Jennifer M. "Influence of land-use change on the long-term persistence of forest understory herbs in the Southern Appalachian Highlands". 2005. http://catalog.hathitrust.org/api/volumes/oclc/62249287.html.
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Tu, Yu-Wen y 杜玉雯. "A Study on the Long-Term Performance Persistence of Active and Passive Management Equity Funds - The Case of U.S.A". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/7fu5d7.
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碩士靜宜大學
管理碩士在職專班
97
The purpose of this study is to research the equity mutual funds’ long-term performance and performance persistence. This study computes monthly performance of 58 mutual funds (including 32 equity funds of active management strategy, and 26 equity funds of passive management strategy) in U.S. domestic large equity funds. The researching period is from Jan. 1998 to Dec. 2007. All the information was provided by month. There are totally 120 months. Major researching results are summarized as follows: 1. Equity funds performance This study examines the performance of equity funds are estimated by average monthly return, and Sharp Index. In equity funds performance, our estimates provide evidence that both active management strategy and passive management strategy have positive average monthly return, and Sharp Index. But the yearly performance of equity funds by the active management strategy outperforms equity funds of passive management strategy. 2. Equity funds performance persistence This study uses Spearman correlation analysis to examine the equity funds performance persistence. Our empirical results show, both of equity funds performances ranked by average monthly return, and Sharp Index lack for persistence.
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Kruger, Tamara Lauren. "Long term prospects for the persistence of breeding Verreaux's Eagles (Aquila verreauxii) at the Walter Sisulu National Botanical Garden, Johannesburg". Thesis, 2010. http://hdl.handle.net/10539/8616.
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ABSTRACT
Verreaux‟s Eagles (Aquila verreauxii) have been sighted in the Walter Sisulu National Botanical Garden since the 1940s. The natural habitat surrounding the Botanical Garden, which is utilised for hunting purposes, has undergone extensive urbanisation and subsequently the habitat required by typical prey species, such as Rock Hyrax (Procavia capensis), has decreased. As a result food supplementation during the breeding season was initiated by the Black Eagle Project Roodekrans (BEPR); a non-profit organisation dedicated to the preservation of these urban raptors. With further proposed urban development, the aim of this research was to deduce the long term prospects for breeding Verreaux‟s Eagles at the Botanical Garden. Analyses were carried out on historical aerial photographs to illustrate the decreasing natural habitat available for prey species within a 10 km radius of the eagle‟s nest site. The feeding data collected by the BEPR over a 16 year period (1993 - 2008) were analysed to investigate changes in prey species and breeding data were analysed to detect possible changes in breeding success over the 16 year period. The aerial photograph analysis indicated that prey suitable habitat within a 10 km radius of the nest diminished by approximately 29.7 km2 (9.5 %) from 1984 to 2007. In 2007 approximately 116.7 km2 (37.2 %) of suitable prey habitat remained within this radius, with a further reduction predicted to decrease suitable habitat within this radius, in the following three years, by an additional 1.03 km2 (1.3 %). The feeding data suggested that there has been a switch from Rock Hyrax to other prey species such as Helmeted Guineafowl (Numida melagris) and francolin (Francolinus spp.). The breeding data revealed few inconsistencies with respect to the incubation period, nestling period and post fledging dispersal period which were similar to established studies on Verreaux‟s Eagles. Despite a reduction in the suitable prey habitat and change in prey, breeding has persisted over the 16 year period. Therefore the prospects of these Verreaux‟s Eagles to continue to breed and hunt at the Botanical Gardens will depend on the, as yet unknown, threshold of prey abundance and habitat disturbance.
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Esteves, João Manuel Ferreira. "Evaluation of long term persistence of Diabetes Mellitus Type II treatment newly diagnosed patients in Lisbon and Tagus health administration region : a three year follow up study". Master's thesis, 2015. http://hdl.handle.net/10362/15713.
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RESUMO: Raional: A persistência à terapêutica é o tempo em qualquer antidiabético oral, desde o seu início até à descontinuação de todas as medicações ou até ao fim do período do estudo. Os objetivos deste estudo foi a análise da persistência à terapêutica no segundo e terceiro anos após início do tratamento em doentes adultos diagnosticados na região de Lisboa e Vale do Tejo e determinar o efeito de determinadas variáveis na persistência a longo prazo.
Métodos: Um estudo retrospetivo não interventivo foi desenhado com base nos dados a obter do SIARS (prescrições e aquisições na farmácia) e Pordata. A persistência foi quantificada como a percentagem de doentes que continuam a adquirir pelo menos um antidiabético oral ao segundo e terceiro anos após a compra da primeira receita. A associação entre a persistência e o segundo e terceiro anos com cada uma das co-variáveis foi aferido pelo teste qui-quadrado e os odd ratios foram calculados com recurso a um modelo de regressão logística.
Resultados: A persistência à terapêutica obtida foi de 80% e 62% para o segundo e terceiro anos após início da terapêutica. Odd ratios para primeiro e segundo ano: número de grupos farmacoterapêuticos diferentes (OR = 2.167, 1.807 – 2.598, p = 0.000 / OR = 1.863, 1.621 – 2.142, p = 0.000); idade (OR = 0.914, 0.772 – 1.081, p = 0.294 / OR = 0.875, 0.764 – 1.002, p = 0.054); sexo (OR = 1.163, 0.983 – 1.377, p = 0.079); número de diferentes prescritores (OR = 3.594, 3.030 – 4.262, p = 0.000 / OR = 2.167, 1.886 – 2.491, p = 0.000); instituição de prescrição (OR = 0.725, 0.698 – 0.753, p = 0.000 / OR = 0.683, 0.650 – 0.717, p = 0.000); grupo farmacoterapêutico (OR = 1.056, 1.043 – 1.069, p = 0.000 / OR = 1.077, 1.060 – 1.095, p = 0.000); relação com o médico (OR = 0.834, 0.816 – 0.852, p = 0.000 / OR = 0.799, 0.777 – 0.821, p = 0.000) e custo médio mensal por grupo farmacoterapêutico (OR = 0.954, 0.942 – 0.968, p = 0.000 / OR = 0.930, 0.914 – 0.947, p = 0.000).
Conclusões: O valor da persistência à terapêutica no segundo ano é ligeiramente acima do que é mencionado na literatura e não existem dados para comparar os resultados do terceiro ano. Relativamente ao efeito das co-variáveis no segundo e terceiro anos após o início do tratamento, os resultados são sobreponíveis, sendo que o sexo não está associado à persistência ao terceiro ano.----------------------------------ABSTRACT: Background: Therapy persistence is the time on any antidiabetic medication, from initiation of therapy to discontinuation of all medications or the end of the study period. The aim of the study was to analyse the therapy persistence in the second and third years after treatment initiation in newly diagnosed adult patients in the Lisbon and Tagus Valley region and to determine the effect of several co-variables in the long term persistence.
Methods: A retrospective non-interventional study based on SIARS data (drug prescriptions and acquisitions) and Pordata was designed. Persistence was quantified as the percentage of patients that continued to purchase at least one type of antidiabetic at year 2 and 3 after the date of first prescription acquisition. Association between persistence at second and third years with each of the other co-variables were verified by using the Chi-Square test and odds ratio were calculated using a regression logistic model.
Results: Therapy persistence obtained was 80% and 62% for the second and third years after treatment initiation. Odd ratios for second and third years: number of different pharmacotherapeutic groups (OR = 2.167, 1.807 – 2.598, p = 0.000 / OR = 1.863, 1.621 – 2.142, p = 0.000); age (OR = 0.914, 0.772 – 1.081, p = 0.294 / OR = 0.875, 0.764 – 1.002, p = 0.054); gender (OR = 1.163, 0.983 – 1.377, p = 0.079); number of different prescribers (OR = 3.594, 3.030 – 4.262, p = 0.000 / OR = 2.167, 1.886 – 2.491, p = 0.000); institution of prescription (OR = 0.725, 0.698 – 0.753, p = 0.000 / OR = 0.683, 0.650 – 0.717, p = 0.000); pharmacotherapeutic group (OR = 1.056, 1.043 – 1.069, p = 0.000 / OR = 1.077, 1.060 – 1.095, p = 0.000); relationship with the physician (OR = 0.834, 0.816 – 0.852, p = 0.000 / OR = 0.799, 0.777 – 0.821, p = 0.000) and average cost per month and per pharmacotherapeutic group (OR = 0.954, 0.942 – 0.968, p = 0.000 / OR = 0.930, 0.914 – 0.947, p = 0.000).
Conclusions: Second year therapy persistence value is slightly above of what is referenced in literature and no data was found to compare the third year value. Regarding the effect of the co-variables analysed at second and third years after treatment initiation, the results were overlapping with gender being not associated with persistence at the third year.
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Wannenwetsch, Oliver. "Long-Term Location-Independent Research Data Dissemination Using Persistent Identifiers". Doctoral thesis, 2017. http://hdl.handle.net/11858/00-1735-0000-0023-3DEE-1.
Texto completo
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Cubr, Ladislav. "Autenticita a digitální informace". Doctoral thesis, 2017. http://www.nusl.cz/ntk/nusl-371329.
Texto completoResumen
The dissertation focuses on the authenticity of digitized books in the context of their life cycle (production, preservation, access). First the OIAS high-level conceptual framework for lifecycle management of digital documents maintained by organizations is introduced. Then the current situation of digitized books lifecycle management is described. This part is followed by an introducing to relevant conceptualizations of the authenticity of digital documents and these conceptualizations are analyzed and reviewed. Then framework for analysis of authenticity is established based on previous findings. This framework is then used to identify authenticity requirements for digitized books and to develop a domain-specific conceptualization of the authenticity of digitized books. This conceptualization deploys detailed analysis of risks threatening authenticity during lifecycle management of digitized books. The selected topics of this conceptualization are then the source for the next step, which is to develop a recommended practice for maintaining authenticity of digitized books. This practice is further specified for one partial solution to the problem of maintaining the authenticity of digital documents throughout their life cycle, which is a persistent identification system.