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Thomas, Joaquin Teruji. "Topics in population ethics." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:fa2a09aa-e784-4126-bd4a-0487d3653add.
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This thesis consists of several independent papers in population ethics. I begin in Chapter 1 by critiquing some well-known 'impossibility theorems', which purport to show there can be no intuitively satisfactory population axiology. I identify axiological vagueness as a promising way to escape or at least mitigate the effects of these theorems. In particular, in Chapter 2, I argue that certain of the impossibility theorems have little more dialectical force than sorites arguments do. From these negative arguments I move to positive ones. In Chapter 3, I justify the use of a 'veil of ignorance', starting from three more basic normative principles. This leads to positive arguments for various kinds of utilitarianism - the best such arguments I know. But in general the implications of the veil depend on how one answers what I call 'the risky existential question': what is the value to an individual of a chance of non-existence? I chart out the main options, and raise some puzzles for non-comparativism, the view that life is incomparable to non-existence. Finally, in Chapter 4, I consider the consequences for population ethics of the idea that what is normatively relevant is not personal identity, but a degreed relation of psychological connectedness. In particular, I pursue a strategy based in population ethics for understanding the controversial 'time-relative interests' account of the badness of death.
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Walker, Matthew. "The relative roles of resources and natural enemies in determining insect abundance." Thesis, Imperial College London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342226.
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Stanley, Zachary. "RELATIVE COMPETITIVE ABILITIES, INTERSEXUAL OVERYIELDING, AND POPULATION SEX RATIO CHANGES IN A BRYOPHYTE." UKnowledge, 2019. https://uknowledge.uky.edu/biology_etds/60.
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Unequal sex ratios are widespread in dioecious plants and understanding their cause is important to understanding fundamental aspects of their population dynamics, and yet what causes biased sex ratios in plants is still poorly understood. Competition experiments have been used in plants to predict the outcome of species interactions, but they have rarely been used to help explain sex ratio bias. This study used a response surface competition design to measure the relative competitive abilities of the sexes of the bryophyte Marchantia inflexa (a thallus liverwort of Marchantiaceae) to predict the outcome of competition before the onset of sexual reproductive structures. In bryophytes, dioecy and sex ratio bias is especially common, making them effective organisms for studying sex ratio bias. Given the frequency of female bias in bryophytes, the hypothesis was that females will show a higher competitive ability relative to males. The experiment was conducted in greenhouse conditions at several densities and proportions over the course of seven months. As individuals grew and formed clumps, identities were tracked, and growth measurements were made using photographs and computer imaging software. Both sexes grew on average 41% more with the opposite sex relative to their single-sex cultures. A model predicting future sex ratios showed coexistence between the sexes and predicted a male biased sex ratio of 3.2 males to 1 female. A trade-off was observed for males where single-sex cultures contained more asexual structures than mixed-sex cultures and the reverse for growth rate. Higher levels of asexual reproduction in males in single-sex cultures might be selected for to increase male dispersal for a higher probability of encountering females. This pattern was not found for females. The overyielding results suggest an interaction effect may exist due to niche differentiation between the sexes. In addition, the results suggest that in some dioecious plants a change in sex ratio can occur before differences in their allocation to sexual reproduction.
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Singh, Narinder. "Genetic diversity of wheat wild relative, Aegilops tauschii, for wheat improvement." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/38259.
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Doctor of PhilosophyGenetics Interdepartmental Program
Jesse A. Poland
Wheat is perhaps the most important component in human diet introduced since the conception of modern agriculture, which provides about 20% of the daily protein and calorie intake to billions of people. Adaptable to wide range of climates, wheat is grown worldwide, lending it the potential to mitigate the imminent risk of food security for future population of 9.5 billion people. For developing improved crop varieties in the future, genetic diversity is a key factor in plant breeding. Constraints in wheat evolution and artificial selection practices have resulted in erosion of this ingredient in elite germplasm. However, wheat wild relatives, such as Ae. tauschii, D-genome donor of wheat, are a storehouse for unexploited genetic diversity that can be used for improving wheat for disease and insect resistance, yield, quality, and tolerance to abiotic stresses. More than 1700 genebanks around the world hold over 7 million accessions of these wild relatives. These genebanks are expensive to maintain, therefore, efficient curation is necessary. We developed and implemented a protocol to identify duplicate accessions using genomic tools. Implementing this approach with three genebanks, we identified over 50% duplicated accessions across genebanks. There are over a million Triticeae accessions held collectively, and it is likely as more number of genebanks are tested, there will be decreasing number of unique accessions. Selecting and utilizing the wild genetic diversity is no easy task. Historically, breeders and geneticists have chosen the accessions primarily based on associated phenotypic data. Unless focusing on a targeted trait, this practice is imperfect in capturing the genetic diversity with some other limitations, such as confounding phenotypic data with the testing environment. Utilizing next-generation sequencing methods, we selected a MiniCore consisting of only 40 accessions out of 574 capturing more than 95% of the allelic diversity. This MiniCore will facilitate the use of genetic diversity present in Ae. tauschii for wheat improvement including resistance to leaf rust, stem rust, Hessian fly, and tolerance to abiotic stresses. Hessian fly is an important insect pest of wheat worldwide. Out of 34 known resistance genes, only six have been mapped on the D sub-genome. With swift HF evolution, we need to rapidly map and deploy the resistance genes. Some of the undefeated HF resistance genes, such as H26 and H32, were introgressed from Ae. tauschii. In this study, we mapped three previously known genes, and a new gene from Ae. tauschii accession KU2147. Genes were mapped on chromosomes 6B, 3D, and 6D. Further, identification and cloning of resistance genes will enhance our understanding about its function and mode of action. In conclusion, wild wheat relatives are genetically diverse species, and utilizing the novel genetic diversity in Ae. tauschii will be fruitful for wheat improvement in the wake of climate change to ensure future food security to expected 2 billion newcomers by 2050.
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Horswill, Catharine. "The relative importance of opposing drivers in determining population change in macaroni penguins Eudyptes chrysolophus." Thesis, University of Glasgow, 2015. http://theses.gla.ac.uk/5979/.
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It is widely recognised that both nutrient-driven processes acting from the “bottom-up” and predator-driven processes acting from the “top-down” are important drivers of population change. However, studies that examine how these joint forces influence the population dynamics of oceanic species are lacking. In the Antarctic and Sub-Antarctic ecosystem, human-mediated changes have driven biological change at both ends of the food chain; rapid regional warming at the bottom and heavy exploitation of apex predator populations at the top. Consequently, many populations of marine predators have rapidly changed in size over the last 50-years. Unravelling the effects of bottom-up and top-down forcing on these open ocean ecosystems, has thus been highlighted as an immediate priority for polar scientists. The overall aims of this study were to use demographic, environmental and diet data to unravel the processes that contributed to a population of macaroni penguins at South Georgia declining rapidly between 1985 and 2012. I use mark–recapture modelling to examine the survival rates of macaroni penguins. Over 10 years, birds were marked with subcutaneous electronic transponder tags and re-encountered using an automated gateway system fitted at the entrance to the colony. These findings were combined with a 28-year time series of population counts and productivity measurements in an age-structured state-space population model to disentangle the processes underlying the observed population decline. Finally, I combined stable isotope analysis and tracking data to investigate the individual strategies macaroni penguins might employ to mitigate the effects of density-dependence during the breeding season. Macaroni penguins at South Georgia declined at 6% per year between 1985 and 2000, stabilising thereafter. This study indicates that the population declined in response to recruitment rates being lower than adult mortality. This trend was potentially accelerated by three large mortality events that were possibly associated with top-down predation pressure from giant petrels. Survival rates were low and variable during the fledging year, increasing to much higher levels from age 1 onwards. Year-to-year variability in demographic rates was induced by a combination of individual quality, top-down predation pressure and bottom-up environmental forces. The relative importance of these covariates on survival rates was age-specific, whereby predation pressure had a considerably greater effect during the fledgling year compared with birds older than 1-year. The population trajectory stabilised after 2000 in response to an increase in survival, as well as density-dependent feedbacks upon productivity. In order to minimise the effects of density-dependence during the breeding season and optimise daily energy expenditure, macaroni penguins appeared to make distinct dietary choices that remained highly consistent from year-to-year. Individually specialised foraging strategies occurred in response to seasonal variations in foraging range, conspecific density and prey availability at the foraging sites. The future stability of this population will depend on the carrying capacity of the environment supporting productivity rates at their present level, and the population size and breeding success of giant petrels not increasing so that adult survival rates can remain stable. More broadly, this study highlights the importance of considering multiple causal effects across different life-stages when examining the demography of seabirds, and demonstrates the additional insights that can be gained by using models with increased precision.
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PEREIRA, Dayane Lucia Francisco. "Biologia populacional de Uca victoriana no manguezal de Itacuru??/Coroa Grande, Ba?a de Sepetiba, RJ." Universidade Federal Rural do Rio de Janeiro, 2012. https://tede.ufrrj.br/jspui/handle/jspui/1801.
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Uca victoriana von Hagen, 1987 is a crab belonging to the family Ocypodidae typical from intertidal zones, characterized by a strong sexual dimorphism. This current study was elaborate in order to evaluate the information about biology of the population, more specifically about population structure, spatial distribution, and reproductive aspects of U. victoriana from mangrove of Itacuru?? / Coroa Grande located in Sepetiba Bay, RJ. Three transects were established with three areas on the right bank of the Draga river, and each area containing 10 m long and 2.25 m wide. Crabs were collected monthly during the period of November 2010 to October 2011. The animals were collected using a quadrat of 30 x 30 cm, performing three random replicates in each plot. In laboratory, the animals were separated by sex and it were taken biometric measurements such as carapace width, carapace length, abdomen width, height of the larger chelipod, length of the larger chelipod and length of the gonopod. Sediment samples were collected in three transects to determine the granulometric composition. It was collected a total of 529 individuals in the study period, of which 89 were males, 97 females non-ovigerous, 16 ovigerous females and 327 juveniles. In the population structure the frequency distribution of males and females was unimodal. The average size of the female LC was 5,64 ? 1,73 mm and 4,97 ? 1,53 mm for males. The analysis of size comparison between sexes showed that females are significantly larger (U = 23741.5, p <0.001) than males. The overall sex ratio of population was 1,94:1, predominantly males. In spatial distribution, there was a greater abundance of animals in the area 2, where the predominance of juveniles, ovigerous females and non-ovigerous females was not superior to other transects. The average size of the ovigerous females was 6.67 ? 0.60 mm, ranging from 5.38 to 7.70 mm. Mean fecundity was 424 ? 186 eggs, with a range from 211 to 886 eggs. The average size of the eggs was 0.292 ? 0.011 mm, with a width 0.27 to 0.30 mm. Recruitment occurred in April. The morphological maturity of females was estimated for the size 5.0 mm and 5.9 mm for males. It follows that the U. victoriana population from mangrove studied, showed to be stable, showing juveniles during all of the months. The distribution of U. victoriana was not influenced by temperature or granulometric, suggesting that other factors, for example, the abundance of trees or biologic factors could influence their distribution in the mangrove. The fecundity found in this population correlates with the females size, as occurs in most brachyuran. The reproductive period was seasonal, with higher frequency of ovigerous females in the months of September and October.
A esp?cie Uca victoriana von Hagen, 1987 ? um caranguejo pertencente ? fam?lia Ocypodidae, t?pico de zonas entremar?s, caracterizado por um forte dimorfismo sexual. O presente trabalho teve como objetivo obter informa??es sobre a biologia populacional, mais especificamente em rela??o ? estrutura populacional, distribui??o espacial e aspectos reprodutivos de U. victoriana do manguezal de Itacuru??/Coroa Grande localizado na Ba?a de Sepetiba, RJ. Foi estabelecido um transecto com tr?s ?reas na margem direita do rio da Draga, onde cada ?rea tinha 10 m de comprimento por 2,25 m de largura. Os caranguejos foram coletados mensalmente durante o per?odo de novembro de 2010 a outubro de 2011. Os animais foram coletados utilizando-se um quadrat de 30 x 30 cm, realizando-se tr?s r?plicas aleat?rias em cada parcela. No laborat?rio os animais foram separados por sexo e tomadas as medidas biom?tricas, como a largura da carapa?a, comprimento total, largura do abdome, comprimento do maior quel?podo, altura do maior quel?podo e comprimento do gonop?dio. Amostras do sedimento foram coletadas nas tr?s ?reas para determinar a composi??o granulom?trica. Foi coletado um total de 529 indiv?duos no per?odo de estudo, dos quais 89 eram machos, 97 f?meas n?o ov?geras, 16 f?meas ov?geras e 327 juvenis. Quanto ? estrutura populacional, a distribui??o de frequ?ncia em machos e f?meas foi unimodal. O tamanho m?dio da LC dos machos foi de 4,97 ? 1,53 mm e das f?meas de 5,64 ? 1,73 mm. A an?lise de compara??o do tamanho entre os sexos demonstrou que as f?meas s?o significativamente maiores (U= 23741,5; p< 0,001) em rela??o aos machos. A propor??o sexual da popula??o foi de 1,94:1 (M:F), com predomin?ncia de machos. Na distribui??o espacial, houve maior abund?ncia de animais na ?rea 2, onde a predomin?ncia de juvenis, f?meas ov?geras e f?meas n?o ov?geras foi superior em rela??o ?s outras ?reas. O tamanho m?dio das f?meas ov?geras foi de 6,67 ? 0,60 mm, variando de 5,38 a 7,70 mm. A fecundidade m?dia foi de 424 ? 186 ovos, com uma amplitude de 211 a 886 ovos. O tamanho m?dio dos ovos foi de 0,292 ? 0,011 mm, com uma amplitude de 0,27 a 0,30 mm. O pico de recrutamento ocorreu no m?s de abril. A maturidade morfol?gica das f?meas foi estimada para o tamanho de 5,0 mm e dos machos de 5,9 mm de LC. Conclui-se, que a popula??o de U. victoriana do manguezal estudado demonstrou ser est?vel, apresentando juvenis durante todos os meses. A distribui??o de U. victoriana n?o foi influenciada pela temperatura e granulometria, sugerindo que outros fatores como a abund?ncia de ?rvores ou fatores bi?ticos podem estar influenciando sua distribui??o neste manguezal. A fecundidade encontrada nesta popula??o se correlaciona com o tamanho das f?meas, como ocorre na maioria dos braqui?ros. O per?odo reprodutivo foi sazonal, com maior frequ?ncia de f?meas ov?geras nos meses de setembro e outubro.
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Lefrançois, Jérémie. "L'efficacité relative des traitements des cauchemars et des perturbations de sommeil auprès d'une population de victimes d'abus sexuel." Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/31452.
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L’abus sexuel est une atteinte à l’intégrité physique et psychique d’une personne. De ce trauma, plusieurs conséquences biopsychosociales viennent affecter les diverses sphères de vie de la victime. Les victimes d’agression sexuelle (VAS) sont 7 fois plus à risque de développer un État de stress posttraumatique (ÉSPT)1 qu’une personne sans antécédent d’abus sexuel. Des symptômes posttraumatiques diurnes surviennent et placent la VAS notamment dans un état d’alerte omniprésent, accompagné de pensées intrusives, d’états dissociatifs possibles et de comportements d’évitement. Bien qu’ils soient moins étudiés que ceux vécus durant le jour, les symptômes posttraumatiques nocturnes (e.g. cauchemars récurrents, insomnie) maintiendraient la VAS dans l’ÉSPT et persisteraient au-delà des traitements usuels. Les cauchemars récurrents seraient même liés à un plus haut risque de danger suicidaire. En effet, les VAS seraient plus à risque d’en souffrir (77%) que d’autres types de populations posttraumatiques, entres autres, étant donné que le trauma sexuel survient fréquemment en soirée ou au moment du coucher. En ce sens, plusieurs traitements destinés directement aux symptômes posttraumatiques nocturnes ont vu le jour depuis les trois dernières décennies. Ainsi, ce mémoire doctoral prend la forme d’une recension systématique ayant pour but de documenter l’efficacité des traitements adressés aux cauchemars et aux perturbations de sommeil chez les VAS. Celle-ci inclut une sélection d’études exhaustive et diversifiée ainsi que l’évaluation de la qualité méthodologique des 22 études primaires qui la composent. La codification et l’extraction de données ont été réalisées par trois codificateurs indépendants (kappa= 0,93). Chaque étude primaire recensée a également fait l’objet d’une évaluation systématique de leur qualité méthodologique. Enfin, une fois les données primaires recueillies, des tableaux synthèses ont été effectués, analysés et interprétés en ressortant les informations pertinentes (caractéristiques des échantillons cliniques, caractéristiques méthodologiques, caractéristiques inhérentes aux traitements recensés) autant pour la recherche que pour la pratique clinique.Sexual abuse is a tremendous threat to both physical and psychological integrity of human beings. This prevalent trauma induces several biopsychosocial consequences that affect the various life domains of the victim. Sexual assault victims (SAV) are seven times more at risk of developing posttraumatic stress disorder (PTSD) than someone without a history of sexual abuse. Daytime posttraumatic symptoms arise, and SAV find themselves in a state of hypervigilance, accompanied by intrusive thoughts, potential dissociative states and avoidance behaviors. Although less studied than those experienced during the day, nighttime posttraumatic symptoms (e.g. recurring nightmares, insomnia) would maintain the SAV in PTSD and persist beyond the usual treatments targeting PTSD. Recurring nightmares are even linked to a higher risk of suicidality. Given that sexual trauma often occurs in the evening or at bedtime, SAV are more likely to suffer (77%) from nighttime symptoms than other posttraumatic populations. Several treatments addressing directly nighttime posttraumatic symptoms have emerged over the past three decades. The aim of the present project is to systematically review the effectiveness of these treatments targeting nighttime symptoms (nightmares and sleep disturbances) in SAV suffering from PTSD. This review includes an exhaustive and diversified selection of studies as well as an assessment of the methodological quality of the 22 primary studies that comprise it. Coding and data extraction were performed by three independent judges (kappa = 0.93). Once primary data were gathered, summary tables were rendered, analyzed and interpreted to highlight relevant information on clinical samples, methodological designs and interventions, for both research and clinical practice. Despite the heterogeneity within and between the primary studies, imagery rehearsal therapy (psychological intervention) and prazosin (pharmacological intervention) appear to be the most recurrent and proven effective interventions to treat nighttime PTSD symptoms (such as a significant reduction of nightmares and insomnia symptoms) and to noticeably increase the sleep quality and overall quality of life in SAV. This systematic review highlights the need for further study of the subject, and more importantly the use of complex methodological designs (e.g. larger and more representative clinical samples of SAV, more RCTs, more valid and objective sleep measures). Future research should include quantitative data analysis (as is the case with meta-analysis) for a better understanding of the effectiveness of these treatments and interventions.
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King, Cheryl S. "An Assessment of Sea Turtle Relative Abundance, Distribution, Habitat, and Population Characteristics Within the Kaho'olawe Island Reserve, Hawai'i." NSUWorks, 2007. http://nsuworks.nova.edu/occ_stuetd/113.
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e sea turtle population utilizing habitats within the Kaho‘olawe Island Reserve (KIR) has gone practically unstudied. This baseline assessment (2002-2005) used a combination of aerial and in-water research methodologies designed in conjunction with recording all incidental sightings and opportunistic reports. In addition, cultural insight, previous studies, literature, and other references were reviewed totaling 708 sightings that provided the subsequent information on the occurrence of turtles within the reserve.
Overall, the different research assessment techniques produced similar results, suggesting the validity of the observations. All techniques had their separate merits and played significant roles due to the restrictions imposed on operations within a former military bombing range and the ongoing research activities of the Kaho‘olawe Island Reserve Commission (KIRC) Ocean Resources Management Program. The most superior methodology was the aerial survey for island-wide relative abundances and distributions, but in-water surveys were valuable in assessing turtle population characteristics, especially the fibropapilloma rate and site fidelity. Coastal surveys were done to search for signs of nesting or basking, but none were documented.
This study found turtles most commonly swimming individually in clear, shallow water (1-6m depth) coral reef habitats 5-20m from shore. Besides one female hawksbill (Eretmochelys imbricata), all were greens (Chelonia mydas) with no evidence of fibropapillomatosis. Immature turtles predominated and were fairly evenly distributed with some areas of higher density around Kaho‘olawe, namely in the Kākā, Hakioawa and Kealaikahiki regions. Using photo-identification techniques, the strongest example of site fidelity was one particular turtle being resighted three times in the same location, with an 815-day interval between the first and last sighting. It was most common to find the turtles swimming as opposed to resting or foraging. The twenty foraging observations that were made occurred primarily in the Hakioawa and Kākā regions (depth mean=6m, SD=3.8m, range 1-11m). All were seen foraging on turf algae, as the abundance of macroalgae within the KIR was limited.
General turtle reactions to our presence were quantified roughly. With humans in the water the majority of the turtles kept a safe distance while exhibiting a slow departure from humans; unless approached closer (by free-diving) which typically caused them to flee. Near equal percentages exhibited flight responses versus toleration of our presence. Only one turtle displayed flipper swiping. During aerial surveys, our helicopter flew at ~31m which did not appear to alter turtle behavior as much as expected. As was the case of turtle reactions to our vessel Hākilo, disturbance was difficult to quantify unambiguously. Some turtles dove abruptly and others appeared to be unaffected by our presence, likely due to other variables unknown to us.
Abundance estimates were negatively biased due to availability biases (submerged turtles) and our detection limitations of naturally camouflaged, highly alert animals. Twenty-nine standardized aerial surveys averaged 7.2 turtles (SD=3.4, range 1-14, n=209) per ~60-minute circumnavigation survey yielding a mean density of 0.153 turtles per km (0.248/mile). Nineteen north coast surveys averaged 2.3 turtles (SD=1.76, range 0-6, n=43) per ~20 minute survey, resulting in a mean density of 0.131 turtles per km (0.209/mile). Sixty-seven nearly island-wide snorkel transects yielded a 1.31 turtles/hr mean (transect SD=1.8, range 0-8, n=82). Although effort varied widely, it was most common to incidentally witness one turtle at the surface per (~5-hour) day while different research activities within the reserve were conducted (1.29/day mean, SD=1.26, range 0-6, n=76 field days, n=98 turtles).
Exploratory analyses of correction factors for submerged turtles during aerial surveys and the collation of all sightings and references roughly estimate that fewer than 500 turtles inhabit the KIR (although these results should be used cautiously). KIR-specific turtle diving behaviors must be determined to enable reliable correction factors to be applied to density abundance estimates. Although these research results are not directly comparable to other studies within the rest of the Main Hawaiian Islands because this is the first island-wide study, these low numbers suggest a rather insignificant contribution to the extant population of Hawaiian sea turtles.
This baseline estimate allows for a) future comparisons using these standardized monitoring protocols, and b) the prioritization of restrictions to important KIR habitats, with implications for management on other islands. As the restoration and management of the KIR continues successfully, this reserve has great potential to host a healthy population of sea turtles that would be able to thrive in a non-anthropogenically stressed environment. Therefore this population and nearshore habitat should continue to be monitored and protected.
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Asiimwe, Peter. "Relative Influence of Plant Quality and Natural Enemies on Population Dynamics of Bemisia tabaci and Lygus hesperus in Cotton." Diss., The University of Arizona, 2011. http://hdl.handle.net/10150/203487.
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The bottom-up effects of plant quality and the top-down effects of natural enemies are two of the most important factors governing the abundance, distribution and performance of insect herbivores. Plant quality effects are generally manifested through changes in nutrients, morphology, size or host availability. Natural enemy effects are mainly observed through the action of arthropod predators and parasitoids. The relative influence of these effects has been well studied in several natural and forest ecosystems but has rarely been evaluated in agro-ecosystems. In manipulative field experiments, I examined the relative influence of plant quality and natural enemies on the abundance and performance of Bemisia tabaci and Lygus hesperus, two important pests of cotton.This dissertation begins with an evaluation of the relative influences of plant quality (manipulated through differential irrigation) and natural enemies (manipulated by insecticide exclusion) on the seasonal dynamics of B. tabaci in cotton. I found higher densities of all B. tabaci stages when natural enemy densities were reduced, regardless of level of plant quality. Generally, densities of B. tabaci did not vary with plant quality. Similarly, natural enemy densities and predator:prey ratios were not affected by plant quality, indicating that natural enemies exert a greater influence on seasonal dynamics of B. tabaci than plant quality. I then evaluated the mechanism responsible for herbivore density patterns using cohort-based life table studies. I found lower rates of predation and parasitism when natural enemy densities were reduced across all levels of plant quality, with predation the primary key factor associated with changes in generational mortality. Levels of B. tabaci mortality did not vary with plant quality indicating that the impact of natural enemies was not mediated by the bottom-up effects of plant quality. Finally, I evaluated these effects on L. hesperus and found that plant quality significantly affected seasonal dynamics with the greatest and smallest densities on the highest and lowest quality plants, respectively. These effects did not translate to natural enemy effects, as their density and impact were not affected by plant quality. The implications of these findings for the management of these pests in cotton are discussed.
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Mazánková, Věra. "Spektroskopické studium dohasínajících výbojů v dusíku a jeho směsích." Doctoral thesis, Vysoké učení technické v Brně. Fakulta chemická, 2009. http://www.nusl.cz/ntk/nusl-233291.
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Presented thesis gives results obtained during the spectroscopic observations of post –discharges of the pure nitrogen plasma with small oxygen admixture and in the nitrogen – argon mixture and the effect of the pink afterglow in it. The DC discharge in the flowing regime has been used for the plasma generation. The decaying plasma was study by optical emission spectroscopy, mainly in the range of 300–800 nm. The first positive, second positive, first negative nitrogen spectral system and NO spectral systems were observed in measured spectra. The band head intensities of these bands have been studied in the dependencies on experimental conditions. Simultaneously, the relative vibrational populations on the given nitrogen states have been calculated. Two discharge tubes made from different materials (PYREX glass and QUARTZ glass) were used in the case of nitrogen plasma containing low oxygen traces (up to 0.2 %). These experiments have been carried out at two wall temperatures for the determination of the temperature effect on the post-discharge. The discharge tube around the observation point was kept at the ambient temperature (300 K) or it was cooled down to 77 K by liquid nitrogen vapor. The total gas pressure of 1 000 Pa and the discharge current of 200 mA were conserved for all these experiments. The relative populations of electronic states were calculated in the dependence on the post-discharge time. The dependencies on oxygen concentration were given, too. The results showed no simple dependence of vibrational populations on oxygen concentration. Generally, slight increase of neutral nitrogen states populations was observed with the increase of oxygen concentration. These observations were well visible due to the intensity of nitrogen pink afterglow effect that was well visible at all oxygen concentrations. The pink afterglow maximal intensity was reached at about 5–10 ms at the wall temperature of 300 K in the PYREX tube. The molecular ion emission was strongly quenched by the oxygen and as this was dominant process for the pink afterglow emission the pink afterglow effect disappears at oxygen concentration of about 2000 ppm. The temperature and wall material influences were observed, too. The post-discharge in nitrogen argon mixtures was studied only in the PYREX tube at the ambient wall temperature of 300 K. The power dissipated in an active discharge was constant of 290 kW. The experimental studies had two new parameters – total gas pressure (500 Pa – 5 000 Pa) and the argon concentrations that were varied in the range of 0–83 %. Also in this case the dependencies of relative intensities of the bands given above were obtained and further the relative populations of electronic states as a function of decay time, total gas pressure and on argon concentration were obtained. The pink afterglow effect was observed at all applied discharge powers and total gas pressures. At the highest argon concentrations, especially at lower pressure, the pink afterglow effect disappeared. The presented experimental work is one of the hugest sets of experiments in the nitrogen with oxygen traces and in nitrogen-argon mixtures. These data can be used as a very good fundament for the further studies using wide numeric modeling of the post-discharge kinetic processes.
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Fernholz, Savannah. "Relative Densities, Population Characteristics, and Sampling Efficiency of Bighead and Silver Carp in Reservoirs of the Tennessee River and Cumberland River." Thesis, Tennessee Technological University, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10979492.
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Bighead Carp Hypophthalmichthys nobilis and Silver Carp H. molitrix (collectively referred to as bigheaded carp) were introduced to the United States in the 1970s and escaped into the Mississippi River from aquaculture ponds. Since their escape, bigheaded carp have become established in the Mississippi River Basin, including the Ohio River and its tributaries. More recently, bigheaded carp have invaded the Tennessee and Cumberland rivers. Little research has been conducted on bigheaded carp in Tennessee waters, with preliminary studies investigating the distribution and characteristics of established bigheaded carp populations, including growth rates and recruitment. My study represents the first systematic sampling of bigheaded carp in the Tennessee and Cumberland rivers, both tributaries to the Ohio River, and in large reservoirs in the southeast U. S. Standardized, multi-gear sampling methods were used to sample bigheaded carp in Kentucky Lake and Pickwick Lake on the Tennessee River and Lake Barkley and Cheatham Lake on the Cumberland River in 2017 and 2018. Overnight gill nets were the most effective gear, capturing an average of 17 Silver Carp per gill net gang. Short-set gill nets captured an average of one Silver Carp per gill net gang, and electrofishing captured an average of one Silver Carp per 10-minute electrofishing transect. Maximum total length (TL) was 1,390 mm for Bighead Carp and 1,111 mm for Silver Carp, and the maximum age for both species was 11 years. Average age and condition of Silver Carp was higher in upstream impoundments than downstream, and thus suggested an early invasion period from Ohio River movements. Gonadosomatic index (GSI; egg mass weight to body weight ratio) was also higher in upstream impoundments than downstream impoundments. Higher GSI values were observed in the spring and summer, when bigheaded carp may begin to spawn in response to high flows. Length-at-age estimates for the four reservoirs suggested bigheaded carp growth rates in the Tennessee and Cumberland rivers are similar to other populations in the US, indicating populations may be experiencing density effects in southeastern impoundments. No young of year (YOY) bigheaded carp were captured during the study, but weak and missing year classes due to erratic recruitment patterns are common in bigheaded carp, and monitoring for YOY fish should continue. Mean catch-per-unit-effort (CPUE) was not significantly different among reservoirs for the three gear types, and no significant seasonal variation in mean CPUE was observed for overnight gill nets. A lack of differences in CPUE across sampling seasons suggested population densities could be assessed as agencies could fit into their schedules. Overall, the results represent the first large-scale standardized sampling effort for bigheaded carp across four southeastern states and provide integral population information for natural resource managers. Future monitoring efforts should continue to track characteristics of bigheaded carp populations in the Tennessee and Cumberland rivers and determine effective control and management strategies for populations in large impoundments.
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Ballard, Timothy D. "Cervical Spine Disease and Surgical Intervention in the US Air Force Fighter Aviator Population 2001-2006: An Assessment of Relative Risk." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1214507780.
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Cwalinski, Tim A. "Simulated forecasting of yellow perch (Perca flavescens) relative population density for Indiana waters of Lake Michigan : responses to varying harvest and alewife density." Virtual Press, 1996. http://liblink.bsu.edu/uhtbin/catkey/1036196.
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The yellow perch, (Perca flavescens), is an important commercial and sport fish in Indiana waters of Lake Michigan. The population is currently managed by temporary restrictions of commercial harvest. A computer simulation model was developed to examine the effects of various constant harvest quotas and alewife densities on yellow perch relative numbers.Model design is based on the SLAM II simulation language incorporating a FORTRAN biological subroutine. The age-structured population model includes measured or predicted biological characteristics of the dynamic pool model. Recruitment is based on a preestablished three-dimensional Ricker stock-recruitment function including alewife (Alosa pseudoharengus) species interaction as a constant or stochastic factor. Sex-specific natural mortality rates were established through life history parameter analysis and the von Bertalanffy growth factors. Density-dependent growth is incorporated into each year of a model run and fluctuates with the simultaneous density of fish. Constant levels of commercial harvest ranging from 0 to 700,000 kg were used in 20-year forecasts. Initial conditions for model runs were 1984 and 1994 trawl CPUE levels when yellow perch were at high and low levels, respectively according to standardized sampling. Response variables were examined as mean catches over each forecast length and included: age 2 fish, spawning stock (z 190 mm), and total catch > age 1.Alewife densities had a tremendous impact on mean catches of the response variables. Highest catches under any forecast period occurred when alewife was considered absent from the system. Catches declined as alewife density was increased as a 20-year constant under each harvest regimen.Catches of spawning size fish were maintained at highest levels for all forecast periods when harvest was set to zero. Catches of young fish were moderate with this harvest regimen if initial catch conditions were high such as in 1984. Catches of young fish were always higher in the absence of a commercial fishery if initial catch conditions were low such as in 1994. Low to moderate harvest quotas could maintain moderate levels of young fish for the forecast length if initial model conditions were high. However, these quota levels for the 1984-2004 forecast length resulted in lower mean catches of spawning size fish as compared to the no commercial fishery regimen. The best case scenario for all response variables when initial catch conditions were low was under a no commercial harvest regimen.Department of Biology
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Coget, Grégoire. "Horloge atomique Cs à piégeage cohérent de population avec protocole d’interrogation Auto-Balanced Ramsey." Thesis, Bourgogne Franche-Comté, 2018. http://www.theses.fr/2018UBFCD064/document.
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Cette thèse reporte une horloge atomique à cellule de césium de haute-performance basée sur le phénomène de piégeage cohérent de population (CPT). Cette horloge associe une diode laser DFB (à 895 nm, raie D1 du Cs), un modulateur électro-optique fibré, un modulateur acousto-optique, un système Michelson, une électronique bas bruit contrôlée par une carte FPGA et une cellule à vapeur de césium contenant un mélange de gaz tampon azote-argon. L’horloge exploite un schéma de pompage CPT optimisé nommé push-pull optical pumping (PPOP) permettant la détection de résonances CPT à fort contraste.L’horloge repose sur l’exploitation d’un nouveau protocole d’interrogation pulsé nommé Auto-Balanced Ramsey (ABR). Ce dernier repose sur l’utilisation de deux séquences Ramsey avec des temps noirs de durées différentes. Ce dernier repose sur l’utilisation de deux séquences Ramsey avec des temps noirs de durées différentes. La mise en place de ce protocole ABR-CPT, amélioré par la suite avec symétrisation (SABR-CPT), conduit à une réduction drastique des effets de déplacement lumineux, avec en particulier une diminution de la sensibilité de la fréquence d’horloge aux variations de puissance laser par un facteur 80 comparativement à une interrogation Ramsey-CPT conventionnelle. Cette horloge CPT démontre à ce jour une stabilité relative de fréquence de 2 10-13 τ -1/2, atteignant le niveau record (pour ce type d’horloge) de 2,5 10-15 à 10 000 s. Des travaux annexes de spectroscopie laser en microcellules à vapeur de césium sont aussi reportés dans ce manuscrit. On notera en particulier la démonstration d’un laser stabilisé par spectroscopie sub-Doppler bi-fréquence dans une microcellule Cs avec une stabilité de fréquence préliminaire meilleure que 2 10-12 à 1 s. Ces performances sont 10 fois meilleures que celles de micro-horloges atomiques micro-ondes CPTThis thesis reports a high-performance Cs vapor cell atomic based on coherent population trapping (CPT). This clock combines a DFB diode laser (895 nm, Cs D1 line), a fibred electro-optical modulator, an acousto-optical modulator, a Michelson system, FPGA-based low noise electronics and a N2-Ar buffer gas filled Cs vapor cell. The clock is based on an optimized CPT pumping scheme, named push-pull optical pumping (PPOP), allowing the detection of high-contrast CPT resonances.The clock uses a novel pulsed interrogation protocol named Auto-Balanced Ramsey (ABR). This method is based on the extraction of two error signals derived from two successive Ramsey sequences with different dark periods. The ABR-CPT protocol, improved further with symmetrization (SABR-CPT), allows a drastic reduction of light-shifts effects, yielding in particular to reduce the sensitivity of the clock frequency to laser power variations by a factor 80, in comparison with a standard Ramsey-CPT interrogation. This clock CPT demonstrates a fractional frequency stability of 2 10-13 τ -1/2, reaching the record level (for this kind of clock) of 2.5 10-15 at 10 000 s. Annex laser spectroscopy studies in Cs microfabricated cells were performed in this thesis. We shall note the preliminary demonstration of a laser frequency-stabilized using dual-frequency sub-Doppler spectroscopy in a Cs microcell, exhibiting a fractional frequency stability better than 2 10-12 at 1 s. These performances are 10 times better than those of microwave CPT-based chip-scale atomic clocks
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Karlsson, Torgny. "Stochastic Chemical Evolution : A Study of Scatter in Relative Elemental Abundances in Extremely Metal-poor Stars." Doctoral thesis, Uppsala University, Department of Astronomy and Space Physics, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4702.
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Chemical evolution addresses the problem of the formation of the chemical elements and their evolution throughout the history of the universe. This thesis discusses in particular the chemical evolution in the young universe and what we may learn from the observations of the oldest stars. The present day production of carbon in the Galaxy is also discussed. Interstellar media of young, metal-poor, star-forming systems are expected to show large chemical abundance inhomogeneities due to local supernova explosions. These inhomogeneities are reflected in the surface abundances of the population of longlived, low-mass stars. A stochastic model of the chemical evolution in such systems is presented and used to study the metallicity distribution and the scatter in chemical abundance ratios. The model takes into account mixing of the enriched material by turbulent motions and cloud collisions in the interstellar medium as well as infall of pristine matter. The predicted metallicity distribution shows, in accordance with observations of extreme Pop II strars in the Galactic halo, a distinct cut-off at [Fe/H]~-4. However, the fraction of stars below [Fe/H]=-4 agrees with observatrion only if a population of metal-free stars (Pop III) was never able to form. The predicted scatter in abundance ratios is demonstrated to be crucially dependent on the as yet uncertain supernova yields and the relatively small star-to-star scatter is tentatively explained by the averaging of a large number of contributing supernovae and by the selection effects favouring contributions from supernovae in a certain mass range for the most metal-poor stars. Furthermore, stars enriched by one single supernova are predicted to be found in very narrow sequences in the abundance ratio diagrams (so called A/A diagrams). Verification of the existence of such features, called single supernova sequences, is observationally challenging. Abundance analysis of carbon was performed in a large sample of solar-type stars in the Galactic disk using the forbidden [C I] line at 8727 Å. A comparison between the relation of [C/O] with metallicity for the Galactic stars and that of dwarf irregular galaxies suggests that large amounts of carbon are produced today by massive, so called Wolf-Rayet stars. Low-mass stars are less important. This was also demonstrated by modelling the chemical evolution of carbon.
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Moura, Andre Eurico Viola. "Investigating the relative influence of genetic drift and natural selection in shaping patterns of population structure in Delphinids (Delphinus delphis; Tursiops spp.)." Thesis, Durham University, 2010. http://etheses.dur.ac.uk/755/.
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Speciation models relying on geographic barriers to limit gene flow gather widespread consensus, but are insufficient to explain diversification in highly mobile marine organisms. Adaptation to different environments has been suggested as an alternative driver for differentiation, particularly in cetaceans. In this study, patterns of population structure at neutral and functional markers were investigated for both common (Delphinus delphis) and bottlenose dolphin (Tursiops spp.), chosen due to high levels of morphological and ecological variation within each genus. Candidate functional markers were selected by investigating signals of positive selection in both mammals and cetaceans. No population structure was found in the European common dolphin for neutral microsatellite loci, in contrast to what is observed in other sympatric cetacean species. The previously described differention of the Eastern Mediterranean Sea population, probably results from a recent human-mediated bottleneck. Functional markers showed almost complete uniformity suggesting purifying selection. One non-synonymous mutation in β-casein and the DQβ1 locus were exceptions, with patterns of population differentiation possibly the result of differences in local selective pressures. Additionally, large mitogenomic sequences were used to investigate the worldwide phylogeography of several ecotypes/species within the genus Tursiops, with a recent biogeographical calibration point being used to calculate divergence times. Good node resolution with high statistical support was achieved, with good separation between most ecotypes in their own lineages. However, the results give no support for a monophiletic Tursiops. Divergence times are clustered in specific geological periods characterized by climatic fluctuations from cold to warmer periods. The Common and bottlenose dolphins exhibit contrasting patterns of population structure in an environment containing few geographical barriers. Such difference is speculated to be related with different feeding ecologies and social structures, although data on such are still limited. Although selection can be detected in the genomes of cetaceans both at the species and population level, current patterns of differentiation are thought to occur mainly due to drift.
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Viola, de Moura Andre Eurico. "Investigating the relative influence of genetic dritt and natural selection in shaping patterns of population structure in Delphmids (Delphinus delphis; Tursiops spp.)." Thesis, Durham University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.534405.
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Yu, Xue Qin. "Comparing survival from cancer using population-based cancer registry data - methods and applications." University of Sydney, 2007. http://hdl.handle.net/2123/1774.
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Doctor of PhilosophyOver the past decade, population-based cancer registry data have been used increasingly worldwide to evaluate and improve the quality of cancer care. The utility of the conclusions from such studies relies heavily on the data quality and the methods used to analyse the data. Interpretation of comparative survival from such data, examining either temporal trends or geographical differences, is generally not easy. The observed differences could be due to methodological and statistical approaches or to real effects. For example, geographical differences in cancer survival could be due to a number of real factors, including access to primary health care, the availability of diagnostic and treatment facilities and the treatment actually given, or to artefact, such as lead-time bias, stage migration, sampling error or measurement error. Likewise, a temporal increase in survival could be the result of earlier diagnosis and improved treatment of cancer; it could also be due to artefact after the introduction of screening programs (adding lead time), changes in the definition of cancer, stage migration or several of these factors, producing both real and artefactual trends. In this thesis, I report methods that I modified and applied, some technical issues in the use of such data, and an analysis of data from the State of New South Wales (NSW), Australia, illustrating their use in evaluating and potentially improving the quality of cancer care, showing how data quality might affect the conclusions of such analyses. This thesis describes studies of comparative survival based on population-based cancer registry data, with three published papers and one accepted manuscript (subject to minor revision). In the first paper, I describe a modified method for estimating spatial variation in cancer survival using empirical Bayes methods (which was published in Cancer Causes and Control 2004). I demonstrate in this paper that the empirical Bayes method is preferable to standard approaches and show how it can be used to identify cancer types where a focus on reducing area differentials in survival might lead to important gains in survival. In the second paper (published in the European Journal of Cancer 2005), I apply this method to a more complete analysis of spatial variation in survival from colorectal cancer in NSW and show that estimates of spatial variation in colorectal cancer can help to identify subgroups of patients for whom better application of treatment guidelines could improve outcome. I also show how estimates of the numbers of lives that could be extended might assist in setting priorities for treatment improvement. In the third paper, I examine time trends in survival from 28 cancers in NSW between 1980 and 1996 (published in the International Journal of Cancer 2006) and conclude that for many cancers, falls in excess deaths in NSW from 1980 to 1996 are unlikely to be attributable to earlier diagnosis or stage migration; thus, advances in cancer treatment have probably contributed to them. In the accepted manuscript, I described an extension of the work reported in the second paper, investigating the accuracy of staging information recorded in the registry database and assessing the impact of error in its measurement on estimates of spatial variation in survival from colorectal cancer. The results indicate that misclassified registry stage can have an important impact on estimates of spatial variation in stage-specific survival from colorectal cancer. Thus, if cancer registry data are to be used effectively in evaluating and improving cancer care, the quality of stage data might have to be improved. Taken together, the four papers show that creative, informed use of population-based cancer registry data, with appropriate statistical methods and acknowledgement of the limitations of the data, can be a valuable tool for evaluating and possibly improving cancer care. Use of these findings to stimulate evaluation of the quality of cancer care should enhance the value of the investment in cancer registries. They should also stimulate improvement in the quality of cancer registry data, particularly that on stage at diagnosis. The methods developed in this thesis may also be used to improve estimation of geographical variation in other count-based health measures when the available data are sparse.
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Takano, Bruno Fernandes. "Estrutura populacional, crescimento somático e alométrico, biologia reprodutiva e estimativa do tamanho populacional de Aegla perobae Hebling & Rodrigues, 1977 do município de São Pedro, estado de São Paulo." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-18012012-103838/.
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Os eglídeos são endêmicos da região Neotropical da América do Sul. São animais exclusivos de água doce, ocorrendo principalmente sob rochas, no folhiço ou mesmo enterrados na areia (Burns, 1972; Rodrigues & Hebling, 1978; Swiech-Ayoub & Masunari, 2001a) em lagos, rios de correnteza, arroios e até mesmo rios de caverna. Os eglídeos são considerados importantes elos na cadeia alimentar de ambientes límnicos agindo como predadores de larvas aquáticas (Magni & Py-Daniel, 1989) e como presas de peixes, anfíbios, répteis, aves e mamíferos (Arenas, 1976; Melo, 1990; Pardini, 1998). Os objetivos dessa dissertação foram realizar um amplo estudo sobre a biologia de Aegla perobae com ênfase na estrutura e dinâmica populacional, crescimento alométrico, biologia reprodutiva e, finalmente, avaliação do grau do risco de extinção com base em estimativas do tamanho populacional e locais de ocorrência. No capítulo 1 são caracterizados aspectos populacionais relacionados a variáveis ambientais e determinadas curvas de crescimento somático de machos e fêmeas. No capítulo 2 foram realizadas análises de regressão linear para determinação do estado de alometria e maturidade morfométrica de machos e fêmeas. Foram identificados quatro morfotipos após a muda da puberdade dos machos adultos e ficou evidente que apenas dois desses morfotipos participam ativamente da reprodução. No capítulo 3 são avaliadas características reprodutivas das fêmeas de A. perobae com base no período reprodutivo, fecundidade e relação com fatores abióticos. No capítulo 4 é estimado o tamanho populacional e examinados os locais de ocorrência de eglídeos próximos à região da cuesta de São Pedro para determinação do grau do risco de extinção. Segundo avaliação baseada em critérios da IUCN (2001) somada a dados biológicos analisados nessa dissertação, conclui-se que a população de A. perobae do município de São Pedro e região encontra-se na categoria de criticamente em perigo de extinção e necessita de especial atenção para sua preservação.Aeglids are endemic to the neotropical South America. They are restricted to freshwaters, mainly occurring under rocks and fragmented leaves or buried in the sand (Burns, 1972; Rodrigues & Hebling, 1978; Swiech-Ayoub & Masunari 2001a) in lakes, rivers, streams and even rivers running into caves. The aeglids are important links in the food chain of freshwater environments acting as predators of aquatic larvae (Magni & Py-Daniel, 1989) and as prey by fish, amphibians, reptiles, birds and mammals (Arenas, 1976; Melo, 1990; Pardini, 1998). The aim of this study was to investigate the biology of Aegla perobae with emphasis on structure and population dynamics, allometric growth and reproductive biology to finally classify the risk of extinction this specie based on estimative of population size and your occurrence locations. In chapter 1 we discuss aspects related to population and environmental variables, and it is determined the somatic growth of males and females. In chapter 2 were performed linear regression analysis to determine the state of allometry and morphometric maturity of male and female. We identified four morphotypes after the puberty molt in adults males and it was evident that only two of these morphotypes participate actively of reproduction. In Chapter 3 we evaluated the reproductive traits of A. perobae females based on the reproductive period, fecundity and the relationship of reproductive females abundance with environmental factors. In chapter 4 the population size is estimated and the sites of occurrence of aeglids near the region of São Pedro are examined to determine the degree of risk of extinction of A. perobae. According to evaluation based on IUCN criteria (2001), added to biological data analyzed in this study, we concluded that the population of A. perobae of the county of São Pedro is critically endangered and requires special attention for its preservation.
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Burton, Nicola Winship. "The relative contribution of psychological, social, and environmental variables to explain variation in leisure-time physical activity among adults at a population level." Queensland University of Technology, 2006. http://eprints.qut.edu.au/16258/.
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Background Information: There is substantial evidence demonstrating the significant benefits of regular physical activity (PA) and the burden of morbidity and mortality associated with inactivity. In Australia however, approximately 40% of the adult population is not meeting recommended levels of PA, the rates of inactivity may be increasing, and improving population levels of PA has been identified as a public health priority. Research is needed therefore, to develop a better understanding of the variables that limit and facilitate PA levels within the population, so as to guide the development of population-based PA promotion. Although a range of psychological, social and environmental variables have been associated with PA, few studies have integrated correlates across these domains and compared their relative contribution. The current evidence base is also limited by too few population-based studies, insufficient assessment of the measurement properties of correlate scales, minimal information on PA item non-response, and a lack of specificity among PA domains. Aims: This research program aimed to develop measures and examine the relative contributions of self-reported psychological, social, and environmental variables to explain variation in leisure-time PA (LTPA) among adults in the general population. Methods: This research program comprised three studies that utilised a crosssectional design and a mail survey methodology with a population-based random sample drawn from Brisbane, Australia (N=5000). Study one involved development and assessment of the measurement properties of a battery of scales to measure correlates of LTPA, using principal components and internal reliability analyses. Study two assessed the magnitude of and sociodemographic variables associated with LTPA item non-response on the mail survey, using logistic regression. Study three examined the independent contributions of self-reported psychological, social, and environmental variables to variation in walking, moderate- and vigorousintensity LTPA, using logistic regression adjusted for sociodemographic covariates. Results: Study one produced a battery of 28 scales to assess self-reported psychological, social and environmental correlates of LTPA. The scales used a total of 123 items to measure activity history (habit, mastery, exposure), health (physical, psychological), activity-related cognitions (self schemata, activity schemata, demand, need, knowledge), self-efficacy, anticipated benefits (psychological, health, challenge, improved appearance, social, weight management), perceived barriers (expense/low access, poor skill, poor personal functioning, time organization, disinterest, family obligations), social support (encouragement, discouragement) and neighborhood environment (available facilities, physical characteristics, aesthetic features, traffic). Of the 28 scales that were factorially derived, 25 had acceptable or marginal levels of internal consistency with Cronbach's alpha values ranging from 0.65 to 0.89. Study two indicated that 28% of the mail survey respondents had incomplete LTPA data with 8% of respondents missing the walking item, and 18% and 23% missing the vigorous-intensity and moderate-intensity LTPA items respectively. Respondents who missed all three LTPA items were more likely than those with complete LTPA data to be female, less educated, from low-income households, in poor health, and a current smoker. Respondents who missed the walking item were significantly more likely to be a current smoker, and to have limited education and low household income. Incomplete moderate-intensity LTPA data was associated with single parenthood and vocational education. Those who missed the vigorousintensity LTPA item were more likely to be 35-54 years old, in fair or poor health, and obese. Respondents with incomplete LTPA data were also more likely to miss sociodemographic items assessing education, household composition, and household income. In study three, the sociodemographic and correlate variables collectively accounted for 43% of the variation in total LTPA, 45% of vigorous-intensity LTPA, 26%of walking, and 22% of moderate-intensity LTPA (Nagelkerke R square). The individual correlates accounted for 0.0 - 4.0% of unique variation across the different domains of LTPA. Habit, self-efficacy, and social encouragement tended to contribute more unique variation for each LTPA domain. Physical health, discouragement, competition, and time management barriers contributed more unique variation to vigorous-intensity LTPA. Anticipated benefits of social interactions and weight management contributed more unique variation to moderate-intensity LTPA. Neighbourhood aesthetics contributed more unique variation to walking variation. Conclusions. This research program demonstrates the importance of integrating psychological, social, and environmental variables to explain PA, and that the relative importance of these correlates is likely to differ among PA domains. More research is needed to enhance the conceptualisation and measurement of correlate variables, in particular PA opportunities across the lifecourse, the anticipated benefit of a balanced lifestyle, the barriers of an unpredictable lifestyle and family obligations, social discouragement, and environmental variables. Population-based mail surveys of LTPA may under-represent population subgroups that are insufficiently active for health, and proactive strategies are needed to maximise their full participation in research and obtain complete survey data, in particular among individuals of low socioeconomic position and for the assessment of moderateintensity LTPA. Generic promotion to increase overall levels of LTPA in the population could focus on promoting self-efficacy for PA and habitual LTPA, as well as enhancing social encouragement. Tailored promotion for vigorous-intensity LTPA could reduce barriers associated with physical health, discouragement, competitiveness, and time management. Tailored promotion for moderate-intensity LTPA and walking should focus on supportive local neighbourhoods and promote the benefits of weight management and social interactions. In time, the successful implementation of such policy and promotion may arrest the decline of PA levels in the population, reduce preventable morbidity and mortality and economic burden associated with inactivity, and facilitate improved health for all Australians.
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Mizzi, Stephen. "The influence of seasonal variation on in-shoe temperature and relative humidity during moderate exercise in a Maltese population : implications for diabetic foot ulceration." Thesis, Canterbury Christ Church University, 2016. http://create.canterbury.ac.uk/15679/.
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Temperature and humidity (microclimate) are key factors implicated in the development of pressure ulceration, however, microclimate in-shoe has been relatively understudied in research related to diabetic foot ulceration (DFU). Additionally, the influence of ambient climate on these parameters in-shoe has also been overlooked. Such information is needed since footwear guidelines to prevent DFU commonly emerge from countries with cooler climates and it is not known whether their application in warmer Mediterranean climates is beneficial. Preliminary validation studies demonstrated suitability of the thermistors (ICC r = 1; Bland and Altman limits of agreement of -0.42°C and 95% CI -1.96, 1.14) and relative humidity sensors (ICC r = 1; Bland and Altman limits of agreement of -0.6°C and 95% CI -1.8, 0.6) for use in in-shoe measurement during ambulation when compared with the gold reference instruments. A reliable repeated measure of in vivo application during shod gait with a thermistor and RH sensor attached between first and second toe and beneath the navicular, was demonstrated. To assess influence of season on in-shoe microclimate, 14 healthy participants walked for 38 minutes on a treadmill in winter and in summer, establishing normative data which was then compared with data from diabetic participants (n=5) using the same protocol. Results demonstrated that seasonal variation has a significant influence (p < 0.01) on inshoe temperature, while no difference was exhibited on in-shoe RH kinetics (p > 0.05). It has been demonstrated that after 20 minutes of walking in Summer, in-shoe skin parameters exceeded 30°C and 70% RH in both healthy and DM participants, levels previously stipulated as indicative of unfavourable parameters to skin resilience in other areas of the body. Therefore, this study provides new Mediterranean-relevant evidence related to in-shoe temperature and RH kinetics during activity, suggestive of negative implications to tissue viability, and also highlighting the need for more climate-specific guidelines related to the use of closed footwear, prescribed to prevent diabetic foot ulceration. It is hoped that this novel information will increase awareness on high in-shoe temperature and RH levels, as potential and influential factors within the pathway of diabetic foot ulceration, in Malta and countries with similar climates.
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Peiró, Douglas Fernando. "Ecologia do caranguejo Austinixa aidae (Righi, 1967) (Crustacea: Brachyura: Pinnotheridae) de uma praia arenosa do litoral Norte do Estado de São Paulo." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/59/59139/tde-17042008-100416/.
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O objetivo deste trabalho foi caracterizar aspectos biológicos e ecológicos de Austinixa aidae, um caranguejo simbionte em galerias construídas pelo Thalassinidea Callichirus major, na Praia do Perequê-Açu, Ubatuba, litoral Norte do Estado de São Paulo. As coletas foram realizadas por meio de bombas de sucção manual na região intermareal da praia arenosa, de Maio/2005 a Setembro/2006. Nesta dissertação foram apresentados, em três capítulos distintos, a Estrutura Populacional, o Crescimento Relativo e as Estratégias Reprodutivas deste caranguejo. No Capítulo I, sua população foi estudada com ênfase em aspectos estruturais como abundância sazonal, freqüência de indivíduos em classes de tamanho, razão sexual, densidade e incidência nas galerias de seus hospedeiros, os períodos reprodutivo e de recrutamento. Além disso, foram avaliadas as correlações entre sua densidade e seu tamanho com o tamanho de seus respectivos hospedeiros. Foi constatado que as espécies do gênero Austinixa possuem aspectos ecológicos e biológicos semelhantes, mesmo em casos de localidades muito distantes geograficamente, corroborando o que foi postulado por outros autores quanto à similaridade destes parâmetros entre os membros do grupo. No Capítulo II, devido ao forte dimorfismo sexual e uma série de adaptações morfológicas atribuídas ao estilo de vida simbionte destes caranguejos, foram estudadas as características corporais, o crescimento relativo, a maturidade e o dimorfismo sexual destes indivíduos. Os adultos de A. aidae possuem a largura da carapaça em média 2,4 vezes o seu comprimento, essas características foram sugeridas como sendo adaptações ao estilo de vida simbionte. O crescimento relativo evidenciou que alterações morfológicas processadas ao longo da ontogenia dos animais estão relacionadas à maturidade sexual da espécie. No Capítulo III, o objetivo foi conhecer a estratégia reprodutiva relacionada à fecundidade, determinando-se o número de ovos produzidos pelas fêmeas ovígeras de distintos tamanhos e em diferentes períodos, além do desenvolvimento dos ovos, seu diâmetro e volume. A. aidae apresentou uma estratégia reprodutiva com padrões característicos de outros crustáceos Decapoda, com evidências de eficiência reprodutiva no local onde esta população está instalada. Considerando a ausência de estudos populacionais e reprodutivos para esta espécie, esta dissertação visou suprir esta demanda na literatura científica.The biological and ecological aspects of Austinixa aidae, a symbiotic crab inhabiting burrows of the Thalassinidea ghost shrimp Callichirus major, from Perequê-Açu beach, Ubatuba, North shore of State of São Paulo, Brazil, were studied. The samples were conducted bimonthly with manual suction pumps in the intertidal region of the sand beach, from May/2005 to September/2006. This project was subdivided into three chapters: Population Structure, Relative growth and Reproductive Strategies. In Chapter I, the population of A. aidae was determined in terms of seasonal abundance, size frequency distribution, sex ratio, density and incidence in the burrows of the thalassinids, reproductive and recruitment periods. In addition, were evaluated the correlations between its density and size with size of their respective hosts. Was found that Austinixa species posses similar biological and ecological aspects, even in distant localities. In Chapter II, due to sexual dimorphism and the morphological adaptations assigned to symbiotic life style, body features, relative growth, maturity and sexual dimorphism were studied. Adults of A. aidae have the carapace width on average 2.4 times the carapace length. Relative growth revealed that morphological changes are related to sexual maturity of this species. In Chapter III, the goal was to know the reproductive strategy related to production of eggs, to determine the fecundity of ovigerous females of different sizes and different periods, conditions of the development of eggs, and their parameters (diameter and volume). A. aidae presented patterns of reproductive strategy similar to other Decapoda crustaceans, with evidence of reproductive efficiency where this population is established. Due to a lack of population and reproductive studies for this species, this study aimed to supply this demand in the scientific literature.
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Charvat, Hadrien. "Le risque attribuable : de la quantification de l’impact populationnel des facteurs de risque à la mesure de l’importance relative des biomarqueurs." Thesis, Lyon 1, 2010. http://www.theses.fr/2010LYO10320.
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Le risque attribuable est un outil épidémiologique apparu dans les années 1950 aujourd’hui encore assez peu utilisé. Il permet d’estimer la proportion de cas d’une maladie potentiellement évitable par suppression ou réduction de l’exposition d’une population à un facteur de risque. Son principal intérêt réside dans la prise en compte concomitante de l’ampleur d’effet du facteur de risque et de la distribution de ce facteur au sein de la population. Après une présentation des caractéristiques essentielles du risque attribuable et des principes de son estimation à partir d’une étude cas-témoins, nous proposons un cadre conceptuel qui permet d’estimer l’impact d’une intervention de santé publique dans une nouvelle population dont l’exposition à certains facteurs de risque diffère de celle observée dans la population d’étude. Une décomposition du risque attribuable permet alors de prendre en compte l’action combinée, ou synergie, des facteurs de risque dans la survenue de la maladie. Parce qu’il donne une dimension populationnelle à l’estimation de l’effet d’une variable, le risque attribuable est particulièrement intéressant pour quantifier l’importance relative des différentes variables explicatives d’un modèle de régression. La question de l’importance relative des biomarqueurs classiques et de ceux issus des technologies à haut débit dans les modèles diagnostiques est actuellement centrale pour établir les apports respectifs de ces deux niveaux d’information. À partir de simulations, nous montrons comment l’apport des nouvelles technologies, quantifié en termes de risque attribuable, peut être faussé par l’utilisation de méthodologies inadaptéesThe attributable risk is an epidemiologic tool that dates back to the fifties but is still relatively seldom used. It estimates the proportion of cases of a given disease that could be avoided if the exposure to a specific risk factor was removed or reduced. Its major interest is that it combines the magnitude of the effect of the risk factor to the distribution of this factor within the population. After a review of the attributable risk main features and the principles of its estimation from case-control studies data, we propose a conceptual framework that allows estimating the impact of a public health intervention in a new population with different exposure to certain risk factors than those observed in the study population. To reach this goal, we used a splitting of the attributable risk that takes into account the combined action –or synergy– of the risk factors on the occurrence of the disease. Because the attributable risk allows estimating the effect of a variable at the population level, it is particularly interesting to quantify the relative importance of the covariates of a regression model. In diagnostic models, the estimation of the relative importance of classic biomarkers and biomarkers obtained from high-throughput technologies is currently crucial in establishing the contribution of each of these two levels of information. Using simulations we have demonstrated the way the role of high-throughput-technologies –quantified in terms of attributable risk– may be wrongly assessed through the use of unsuitable methodology
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Abdel, Hafiz Moustafa. "Development and metrological characterization of a high-performance Cs cell atomic clock based on coherent population trapping." Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCD035/document.
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Ce travail de thèse, effectué dans le cadre du projet européen MClocks (http://www.inrim.it/mclocks), reporte le développement et la caractérisation métrologique d’une horloge atomique à cellule de césium de haute performance basée sur le phénomène de piégeage cohérent de population (CPT). Cette horloge exploite un schéma de pompage CPT optimisé nommé push-pull optical pumping (PPOP), permettant la détection de résonances CPT à fort contraste sur la transition d’horloge 0-0. Une caractérisation détaillée des différents éléments de l’horloge est reportée. L’horloge fut exploitée en mode continu (CW) et en mode impulsionnel de type Ramsey. Dans les deux modes de fonctionnement, l’horloge démontre une stabilité relative de fréquence de l’ordre de 2 10−13 τ−1/2 jusque 100 s d’intégration, principalement limitée par des effets de puissance laser. Cette horloge atomique, parmi les meilleures horloges à cellule développées à travers le monde, pourrait trouver des applications pour les systèmes de télécommunications, d’instrumentation, de défense ou navigation par satellite.Cette thèse reporte aussi une technique originale de stabilisation de fréquence laser par spectroscopie sub-Dopplerbi-fréquence en cellule. La plateforme constituée par l’horloge a été utilisée pour mener des tests de physique plus amont incluant la caractérisation par spectroscopie CPT d’une cellule de césium avec un revêtement anti-relaxant OTS (octadecyltrichlorosilane) ou la caractérisation de microcellules à vapeur de césium avec gaz tampon développées à FEMTO-ST pour des horloges atomiques miniaturesThis thesis work, performed in the frame of the MClocks European project (http://www.inrim.it/mclocks), reports the development and metrological characterization of a high-performance Cs vapor cell atomic clock based on coherent population trapping (CPT). The clock uses an optimized CPT pumping scheme, named push-pull optical pumping (PPOP), allowing the detection of high-contrast CPT resonances on the 0-0 magnetic-field insensitive clock transition. A detailed characterization of key components of the clock is reported. The clock was operated in the continuous-wave (CW) regime and in a Ramsey-like pulsed regime. In both regimes, the clock demonstrates a short-term fractional frequency stability at the level of 2 10−13 τ−1/2 up to 100 s averaging time, mainly limited by laser power effects. This CPT clock, ranking among the best microwave vapor cell atomic frequency standards, could find applications in telecommunication, instrumentation, defense or satellite-based navigation systems.This thesis reports also a novel laser frequency stabilization technique using dual-frequency sub-Doppler spectroscopy in a vapor cell. The clock ”platform” has also been used to perform using CPT spectroscopy the characterization of a Cs vapor cell coated with octadecyltrichlorosilane (OTS) or original buffer-gas filled Cs vapor micro-fabricated cells developed in FEMTO-ST for CPT-based miniature atomic clocks
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Söderling, Peter. "An ecological study of the migration, food composition and relative abundance of three-spined stickleback (Gasterosteus aculeatus) in a shallow area in Kalmar Sound." Thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-49591.
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The populations of three–spined sticklebacks (Gasterosteus aculeatus) in the Baltic Sea have increased tenfold over the last decade. A large increase in abundance can alter the offshore and coastal food webs. Despite of these facts, there are large gaps in the knowledge about the stickleback ecology in the Baltic and the possible effect they might have on their environment. Earlier investigations state that stickleback mainly occupy the deeper areas offshore, and only migrate to the shallow areas during May–July to spawn. Observations by recreational fishermen indicate that this may be incorrect, and that some adult sticklebacks are present in the shallow areas even during the winter. One aim of this study was to investigate the timing of stickleback migration to a shallow coastal area in Kalmar Sound. The study also aimed to examine the relative abundance in two adjacent shallow areas in the archipelago south of Kalmar, where one of the areas is a pike spawning ground. A one month long test fishing with fyke nets was started on the first day after ice break. Results show that the sticklebacks are present in the bays immediately after the ice break, and that high abundances coincide with the pike spawning period. Stomach analyses showed that sticklebacks consumed a large proportion of crustaceans, but also fish eggs were found. These results shed new light on the management actions for many of the coastal spring spawning fish species that have shown decreasing abundances during the last decades.Bestånden av storspigg (Gasterosteus aculeatus) i Östersjön har ökat markant, data visar på en tiofaldig ökning under det senaste decenniet. Ökningen kan medföra att bl.a. näringsväven, till havs och längs kusterna förändras. Trots vetskapen om detta finns det kunskapsluckor kring spiggens ekologi och dess möjliga påverkan på sin omgivning. Litteratur säger att spiggen till största del bara befinner sig inne längs kusterna under maj-juli. Observationer från sportfiskare tyder på att detta inte stämmer, och att vuxen storspigg befinner sig inne längs kusten och i skärgårdsvikar året om. Ett syfte med studien var att undersöka när spiggen kom in till de grunda vikarna i Kalmarsund. Studien jämförde även spiggtätheterna mellan två närliggande områden där den största skillnaden var födan. Ett månadslångt provfiske inleddes den första isfria dagen i två skyddade vikar söder om Kalmar, där en av lokalerna var en dokumenterad leklokal för gäddor. Resultaten visade att spiggen fanns i vikarna direkt efter islossningen, och vid fisket sammanföll de största spiggfångsterna med gäddleken. Maganalyser visade att en stor andel av födan bestod av olika kräftdjur, men även romkorn hittades. Resultaten tyder på andra förutsättningar för många av de hårt ansatta vårlekande fiskarterna än vad som tidigare är dokumenterat.
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Gregory, Callie. "Relative Effectiveness of Anti-poverty Nonprofit Organizations in Assisting a Below Poverty Population in Dallas County and Tarrant County: Recipients of Faith-based and Non Faith-based Organizations." Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115088/.
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Recent orders from the executive branch of the United States’ government have encouraged participation from faith-based organizations in providing human services because they are more effective in aiding impoverished citizens. This study examined the effectiveness of faith-based and non faith-based anti-poverty nonprofit organizations to find if one organization type is more effective in providing social services. the data for this study were collected through a survey-questionnaire which was administered to a convenience sample of 82 participants seeking assistance from four different nonprofit organizations (two faith-based and two non faith-based) in Dallas County and Tarrant County. the results from this study indicated that when controlling for demographic and socio-economic variables, recipients from faith-based organizations were less likely to report that they at least received services desired as compared to those who visited a non faith-based organization. Therefore, non faith-based organizations were better at meeting the needs of respondents than faith-based organizations.
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Dech, Jeffery P. "Population establishment of Galerucella pusilla (Duft.) and G. calmariensis (L.) (Coleoptera, chrysomelidae) and their relative impact on the growth of Lythrum salicaria L. (Myrtiflorae: Lythraceae) in two central Ontario wetlands." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0009/MQ61258.pdf.
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Hestad, Daniel Andrew. "INGESTION OF ENDOPHYTE-INFECTED TALL FESCUE SEED INDUCES PERIPHERAL VASOCONSTRICTION BUT DOES NOT AFFECT CYCLICITY IN NON-PREGNANT MARES, AND A POPULATION OF BIOGENIC AMINE RECEPTORS RELATIVE TO VASOCONSTRICTION IS IDENTIFIED." UKnowledge, 2012. http://uknowledge.uky.edu/gluck_etds/2.
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Three experiments were conducted to explore the effect of fescue toxicosis on vasoconstriction and various parameters of the estrous cycle. In the experiment of Chapter 3, a 2x2 crossover experimental design with repeated measures was implemented to test whether the ingestion of endophyte-infected tall fescue seed would alter blood hormone concentrations of prolactin, progesterone, and estradiol, interovulatory intervals, and corpus luteum blood flow. Also, Doppler ultrasonography was used to assess whether palmar artery and palmar vein lumen diameter, area, circumference, and resistivity index could be altered by the ingestion of endophyte-infected tall fescue seed. Ingestion of endophyte-infected tall fescue seed significantly decreased palmar artery resistivity index, area, and circumference, and palmar artery and palmar vein lumen diameter, but did not alter interovulatory intervals, serum concentrations of prolactin, progesterone, estradiol, or corpus luteum blood flow. Experiments 1 and 2 from Chapter 4 profiled the dopaminergic, serotonergic, and α-adrenergic receptor types and subtypes, as expressed within the equine medial palmar artery, medial palmar vein, and uterine artery transcriptomes. Combined results from Chapters 3 & 4 imply that relative quantity of serotonergic receptor subtypes within a vessel may be related to with the severity of that vessel's vasoconstrictive response to endophyte-infected tall fescue.
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Laine, Kari. "Long-term variations in plant quality and quantity in relation to cyclic microtine rodents at Kilpisjärvi, Finnish Lapland." Oulu, Finland : University of Oulu, 1988. http://catalog.hathitrust.org/api/volumes/oclc/18696609.html.
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MEMMI, MARC MARIE. "Etude genetique de la population corse et sa relation avec les populations euro-mediterraneennes." Corte, 1999. http://www.theses.fr/1999CORT3043.
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L'etude phylogenetique de la population corse, initiee en 1993, s'est concretisee par l'acquisition de donnees issues du polymorphisme de trois marqueurs agglutinogenes (rh, kell et abo), neuf proteines erythrocytaires (acp, ada, ak, dia, esd, glo, 6pgd, pgm1 et sod) et sept proteines plasmatiques (gc, c3, plg, tf, orm, hp et pi). Les 54 alleles totaux ont ete explores sur des prelevements sanguins provenant d'individus d'origine corse et representatifs de quatre microregions definies sur des criteres historiques et geographiques : nord est (n = 210), nord ouest (n = 151), centre (n = 355) et sud ouest (n = 274). Les resultats obtenus sont analyses par l'intermediaire de methodes statistiques et visualises par des dendrogrammes, qui refletent les relations genetiques, d'une part, dans un contexte intra-regional, et d'autre part, entre la population corse dans son ensemble et certaines populations, principalement mediterraneennes. Ces resultats permettent de conclure a l'existence d'une homogeneite genetique entre les populations des differentes microregions insulaires ainsi qu'une derive genetique prononcee due a l'isolement. L'approche inter-regionale, montre que les quatre microregions corses sont tres proches genetiquement des microregions sardes. Ce rapprochement, confirme d'un point de vue archeologique et linguistique, est probablement du a une origine commune de peuplement. Cet ensemble humain corso sarde, se trouve genetiquement associe aux populations du pays basque et de l'afrique du nord, alors que les populations connues pour leur impact culturel, linguistique et historique (grece, latium, toscane, ligurie, france) n'ont genere qu'un flux genique modere. Il semblerait donc que les traces de ce passe lointain soient encore decelables de nos jours, et ceci malgre les nombreuses invasions et occupations qui ont jalonne l'histoire de l'ile depuis des siecles. Appliquee a nos donnees, une methode de datation statistique, montre que l'origine du peuplement du bloc corso-sarde remonterait au paleolithique, en opposition donc avec les connaissances archeologiques actuelles, qui attestent une presence humaine au preneolithique.
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Theka, Takalani P. "Studies of genetic, gastrointestinal, renal and dietary factors in white and black South African subjects as a possible key to understanding the relative absence of calcium oxalate kidney stone disease in the black population." Doctoral thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/6287.
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The incidence of urolithiasis in South Africa's black population is extremely rare «1%) while in the white population it is similar to that of western countries (-15%). The present thesis was aimed at shedding more light on the complex nature of the physicochemical, biochemical and physiological mechanisms in black South Africans which provide this group with a natural protection against urolithiasis in contrast to their white compatriots. Four studies comprise this thesis.
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Lynch, Darren Marc. "Re-conceptualising refugees as relative surplus populations." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ62347.pdf.
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Solomon, Mariaan. "The relative performance of surrogate measures for viable populations." Diss., Pretoria : [s.n.], 2000. http://upetd.up.ac.za/thesis/available/etd-12062006-130505/.
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Michel, Philippe. "Principe d'entropie relative généralisée et dynamique de populations structurées." Paris 9, 2005. https://portail.bu.dauphine.fr/fileviewer/index.php?doc=2005PA090032.
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Dans cette thèse, nous nous intéressons à l'étude et au contrôle de la dynamique de populations structurées, en âge (Mc Kendrick), en taille (modèle de division cellulaire-DVC) ou autres. Pour cela, nous exhibons une famille d'entropies relatives (Entropie Relative Généralisée-GRE) pour des modèles n'ayant pas de loi de conservation simple (masse, taille. . . ). L'existence d'une telle famille et l'étude fine du comportement asymptotique sont conditionnées par l'existence et l'unicité de la solution à un problème aux valeurs propres. L'étude de ce problème dans le cas d'un modèle DVC nous a permis, entre autres, de montrer que le taux de croissance Malthusien de populations cellulaires dépendait de la symétrie de la division. Dans un exemple de modèle en âge non linéaire, on a pu montrer la convergence globale en temps et comparer la méthode GRE à la méthode classique par linéarisationThis thesis deals with the dynamic of population balance equations (PBE) as the Cell Division Equation (CDE) or as the classical McKendrick age model. More precisely, we show a family of relative entropies (General Relative Entropy-GRE) in a large class of PBE. The existence of such a family and a sharp study of the asymptotic behavior is related to the existence and uniqueness of the solution to an eigenproblem. For instance, the study of this eigenproblem in a CDE model, allows us to show the link between the Malthusian growth rate of a cell population an the symmetry of its division. We prove, in a simple nonlinear age model, the global convergence to a steady state and we compare the results given by the GRE method and the linearization method
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Peter, Jackson. "Dissection de la relation génotype-phénotype par des études d'association chez Saccharomyces cerevisiae." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAJ064/document.
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Un objectif central en biologie est de comprendre la relation entre le génotype et le phénotype. Afin de disséquer les bases génétiques de la diversité phénotypique, il est nécessaire de disposer d’une collection de données génomiques d’un grand nombre d’individus d’une même espèce. Dans ce but, mes travaux de thèse se basent sur l’étude des séquences génomiques ainsi que des données phénotypiques de 1011 isolats naturels de la levure Saccharomyces cerevisiae. Dans un premier temps, je me suis intéressé à la description de la variation génétique et phénotypique pour dresser un portrait précis de l’histoire évolutive de cette espèce. Les données de phénotypage nous ont permis de réaliser des études pangénomiques d’association génotype-phénotype avec une puissance jusque là inégalée chez Saccharomyces cerevisiae. Je me suis par la suite penché sur l’évaluation des paramètres influençant le pouvoir de détection d’une telle approche, d’en apprécier limites pour tenter de les contournerElucidating the genetic origin of phenotypic diversity among individuals within the same species is essential to understand evolution. Using whole genome sequences of 1,011 Saccharomyces cerevisiae isolates, my work sought to describe intraspecific genetic variation and investigate of its phenotypic consequences. Doing so, I obtained a precise view of the evolutionary history of S. cerevisiae. Phenotypic characterization provided the opportunity to perform genotype-phenotype genome-wide association studies with unprecedented power. I then focused on the evaluation of the parameters influencing genome-wide association studies, the appreciation of the limits of such an approach, and ways to circumvent them
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Forney, Karin A. "Patterns of variability and environmental models of relative abundance for California cetaceans /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1997. http://wwwlib.umi.com/cr/ucsd/fullcit?p9823699.
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Rahman, Md Rashedur. "Knowledge Base Population based on Entity Graph Analysis." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS092/document.
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Le peuplement de base de connaissance (KBP) est une tâche importante qui présente de nombreux défis pour le traitement automatique des langues. L'objectif de cette tâche est d'extraire des connaissances de textes et de les structurer afin de compléter une base de connaissances. Nous nous sommes intéressés à la reconnaissance de relations entre entités. L'extraction de relations (RE) entre une paire de mentions d'entités est une tâche difficile en particulier pour les relations en domaine ouvert. Généralement, ces relations sont extraites en fonction des informations lexicales et syntaxiques au niveau de la phrase. Cependant, l'exploitation d'informations globales sur les entités n'a pas encore été explorée. Nous proposons d'extraire un graphe d'entités du corpus global et de calculer des caractéristiques sur ce graphe afin de capturer des indices des relations entre paires d'entités. Pour évaluer la pertinence des fonctionnalités proposées, nous les avons testées sur une tâche de validation de relation dont le but est de décider l'exactitude de relations extraites par différents systèmes. Les résultats expérimentaux montrent que les caractéristiques proposées conduisent à améliorer les résultats de l'état de l'artKnowledge Base Population (KBP) is an important and challenging task specially when it has to be done automatically. The objective of KBP task is to make a collection of facts of the world. A Knowledge Base (KB) contains different entities, relationships among them and various properties of the entities. Relation extraction (RE) between a pair of entity mentions from text plays a vital role in KBP task. RE is also a challenging task specially for open domain relations. Generally, relations are extracted based on the lexical and syntactical information at the sentence level. However, global information about known entities has not been explored yet for RE task. We propose to extract a graph of entities from the overall corpus and to compute features on this graph that are able to capture some evidence of holding relationships between a pair of entities. In order to evaluate the relevance of the proposed features, we tested them on a task of relation validation which examines the correctness of relations that are extracted by different RE systems. Experimental results show that the proposed features lead to outperforming the state-of-the-art system
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Kuningas, Sanna. "Population dynamics and distribution of northern Norwegian killer whales in relation to wintering herring." Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/4878.
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The northern Norwegian killer whale (Orcinus orca) is an important predator but little is known about its population dynamics, particular in response to changes in its main prey, the highly dynamic Norwegian spring spawning (NSS) herring (Clupea harengus). The main aims of this thesis were to estimate killer whale population parameters, to explore the future viability of the population, and to explore the response of this predator to changes in distribution and abundance of its main prey over the last 25 years. Population size was estimated as ~ 700 individuals, taking heterogeneity of capture probabilities into account and correcting for unmarked animals. Apparent survival rates of 0.974 (SE = 0.006) for adult males and 0.984 (SE = 0.006) for adult females were estimated accounting for temporary emigration, transience and trap-dependency. Temporary emigration was greater for males than females. Calving intervals ranged from 3 to 14 years (mean = 5.06); equivalent to 0.197 calves per mature female per year. Future viability of the killer whale population was evaluated under various plausible scenarios. The baseline scenario using the best available information predicted a viable population and indicated that the population may be increasing size. Analysis of data on naval sonar activity, killer whale sightings and herring abundance showed that naval sonar activity appeared to have a negative effect on killer whale presence during a period of low prey availability. A time lag of four years was found between the first sign of NSS herring changing its distribution and reduced killer whale presence inside the fjord system. Analysis of energy budgets showed that killer whales spent more time travelling/foraging in 2005/06 than the 1990s. The fjord system was inferred to be a preferred habitat for killer whales when there was a higher density of NSS herring in this area compared to offshore area.
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Jan, Camille. "Population structure of swarming bats in relation to dispersal." Thesis, University of Leeds, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540207.
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Stiefs, Dirk. "Relating generalized and specific modeling in population dynamical systems." Tönning Lübeck Marburg Der Andere Verl, 2009. http://d-nb.info/997031107/04.
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Basey, Gary L. "Relative abundance and habitat characteristics of woodland hawks in east-central Indiana." Virtual Press, 1998. http://liblink.bsu.edu/uhtbin/catkey/1115728.
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This study investigates the status and habitat characteristics of the Cooper's Hawk (Accipiter cooperi), the Red-shouldered Hawk (Buteo lineatus), the Broadwinged Hawk (Buteo platvpterus), and the Red-tailed Hawk (Buteo 'amaicensis) in East-central Indiana to provide information useful for the conservation of these species. Surveys of hawks were conducted using taped Great-horned Owl broadcasts at 350 points between April and July, 1995 and 1996. The relative abundance was estimated using the proportion of area occupied technique. Estimates of the proportion of area occupied by each species ranged from 4% to 34%. Red-tailed Hawks were estimated to occupy 34% of the area surveyed. Estimates of the area occupied by Cooper's Hawks was 8% and by Red-shouldered Hawks was 4%. Broad-winged Hawks only occupied two points, therefore no estimate of the area occupied was determined. Macro-habitat characteristics were quantified for each species within a 0.8-km radius of the center of each occupied area and were compared with randomly selected unoccupied areas. Large forested areas with less human development were most preferred by Red-shouldered and Broad-winged Hawks. Cooper's hawks and Red-tailed hawks were found in a wide variety of habitat types.Department of Biology
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Middleton, Jessica. "Population ecology of a declining amphibian in relation to density." Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=114513.
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In species with complex life cycles such as amphibians, population regulation can occur in one or multiple stages. Density effects in the larval, aquatic stage of the amphibian life cycle have been widely documented, leading many researchers to assume that this is the stage in which amphibian populations are regulated. However, recent evidence suggests that factors affecting survival and reproduction in the terrestrial stage may play a greater role in the growth and decline of amphibian populations than previously thought. I review the evidence for density-dependent population regulation in the terrestrial stage of amphibians and argue that variation in body size may be an important mechanism linking population density to changes in population growth rate (CHAPTER ONE). I used data from a 23-year population survey at Long Point, Ontario and conducted summer growth-rate surveys to examine the body size-abundance relationship in Fowler's Toad (Anaxyrus fowleri). Over the past 10 years of the population survey at Long Point, we observed a significant increase in body size (R² = 0.874, p = <0.001) that was coincident with a previously detected negative trend in abundance. The age structure of this population is highly unstable, but overall the average age is getting older (R² = 0.325, p= < 0.01) (CHAPTER TWO). Somatic growth rates in Fowler's toad toadlets are also highly variable and are significantly inversely correlated with the density of adults (R² = 0.98, p = 0.010) (CHAPTER THREE). The single most important factor influencing average body size on a long time-scale is abundance (R² = 0.713, p = <0.001) (CHAPTER FOUR). Therefore, body size variation in these toads is likely related to density-dependent resource availability for growth in the terrestrial stage.Pour des espèces ayant des cycles de vie complexes tels les amphibiens, la régulation de leur population peut se produire dans un ou plusieurs stades. Les effets de la densité au stage larvaire aquatique du cycle de vie de l'amphibien ont été largement documentés amenant plusieurs chercheurs à assumer que c'est à ce stage que la régulation de leur population se produit. Toutefois, des preuves récentes suggèrent que des facteurs affectant la survie et la reproduction au stage terrestre peuvent jouer un plus grand rôle dans la croissance et le déclin de la population des amphibiens contrairement à ce que l'on pensait auparavant. Je fais la revue de la preuve de la régulation de la population qui dépend de la densité au stage terrestre des amphibiens et j'argumente que la variation de la masse corporelle pourrait être un mécanisme important reliant la densité de la population aux changements du taux de croissance de la population (CHAPITRE UN). J'ai utilisé les données d'un relevé de la population sur une période de 23 ans à Long Point, Ontario et mené des relevés du taux de croissance durant l'été afin d'examiner la relation entre la dimension et la masse corporelle du crapaud de Fowler (Anaxyrus fowleri). Durant les 10 dernières années du relevé de la population à Long Point, nous avons remarqué une augmentation significative de la masse corporelle (R² = 0.874, p = <0.001) qui coïncidait avec une tendance négative de leur abondance détectée précédemment. La structure de l'âge de cette population est très instable, mais dans l'ensemble la moyenne d'âge est plus vieille (R² = 0.325, p= < 0.01) (CHAPITRE DEUX). Les taux de croissance somatiques des petits du crapaud de Fowler sont hautement variables et inversement corrélatifs à la densité des adultes (R² = 0.98, p = 0.010) (CHAPITRE TROIS). Le seul facteur d'importance qui influence la dimension corporelle moyenne sur une longue période c'est l'abondance (R² = 0.713, p = <0.001) (CHAPITRE QUATRE). Ainsi, la variation de la dimension corporelle de ces crapauds est vraisemblablement reliée à la croissance somatique laquelle dépend de la densité au stage terrestre.
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Kaczmarek, Agata. "Population dynamics of potato cyst nematodes in relation to temperature." Thesis, University of Dundee, 2014. https://discovery.dundee.ac.uk/en/studentTheses/803ed5ab-cbed-4164-9c6d-0c3026229bc5.
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Population dynamics of potato cyst nematodes Globodera rostochiensis (Woll.) Skarbilovich and G. pallida (Stone) and their interactions with potato plants are not sufficiently described to explain changes in population dynamics and yield reduction among seasons and locations. This thesis describes experiments to clarify the mechanisms of PCN population increase and associated damage to potato primarily in relation to temperature. The research was undertaken in controlled environments and in the field to examine the impact of temperature and mixed populations on the life cycle and population dynamics of potato cyst nematodes. The data will be used to develop a model that relates the PCN life cycle with temperature. Soil temperature data were also obtained from different UK locations within potato drills during the growing season to provide a context for the model. Results from this thesis indicate that both species of PCN, Globodera rostochiensis and G. pallida, are likely to increase more rapidly and in greater numbers with susceptible cultivars if soil temperatures increase in the future and regions of the UK with relatively higher soil temperatures are more likely to have higher and faster population multiplication of PCN.
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Mwafongo, Elizabeth. "Population ecology of Aloe Plicatilis (Liliaceae) in relation to disturbance." Bachelor's thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/26703.
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Gransden, Scott G. "The relative effects of food concentration and predation in controlling tropical ciliate populations." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ27500.pdf.
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Garzia, Nichole Andrea. "Surveillance of asthma in relation to work among Canada's adult population." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2471.
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Work-related asthma surveillance is needed to improve management of occupational exposures, clinical recognition/diagnosis, and worker compensation policies. This work investigated asthma in relation to work by evaluating the utility of existing Canadian surveillance data in providing useful information about the burden of work-related asthma; estimating the burden of work-related asthma among Canada's adult population; and evaluating the effect of job risk on asthma after considering other potential risk factors for asthma.
The working population formed samples from two Statistics Canada surveillance programs: Canadian Community Health Survey (CCHS), 2002/03 Cycle 2.1 and National Population Health Survey (NPHS), Longitudinal Component (1994/95-2002/03). Both surveys enquired about health professional-diagnosed asthma; NPHS additionally asked age at time of diagnosis, so adult-onset versus childhood-onset asthma was determined. Both surveys enquired about current job held; corresponding job codes were linked to an asthma-specific job exposure matrix to judge job risk for occupational asthma. CCHS only provided current job information, in contrast, NPHS longitudinal data was used to determine job held at time of asthma-onset. Statistical measures for asthma in relation to job risk were estimated.
CCHS results were likely biased by the healthy worker effect, as it showed the opposite effect of job risk on asthma than the NPHS; higher asthma prevalence was shown for NPHS men and women in high risk jobs. NPHS results indicated a large burden of adult-onset asthma among men (19,000) and childhood-onset asthma among women (17,000) attributed to working in high risk jobs for occupational asthma. Using NPHS, adjusted and crude prevalence odds ratio estimates were compared to further assess effect of job risk on asthma. For adult-onset asthma, there was no difference between estimates (men: 1.8, women: 1.1); for childhood-onset asthma, adjusted estimates were larger than crude, respectively (men: 1.3 v 1.2, women: 2.0 v 1.7).
Age of asthma-onset and job held at time of asthma-onset is necessary surveillance information for estimating work-related asthma. There may be increased risk of work" caused" asthma among men and work "exacerbated" asthma among women in high risk jobs. Considering other risk factors for asthma did not reduce effect of job risk on asthma.
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Batty, Karen. "Population dynamics of epiphytic lichens in relation to changing air quality." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298886.
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Emery, Keith Martin. "Population dynamics of Birdsfoot trefoil in relation to disease and microclimate /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9842525.
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Wennerström, Lovisa. "Population genetic patterns in continuous environments in relation to conservation management." Doctoral thesis, Stockholms universitet, Zoologiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-131223.
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Genetic variation is a prerequisite for the viability and evolution of species. Information on population genetic patterns on spatial and temporal scales is therefore important for effective management and for protection of biodiversity. However, incorporation of genetics into management has been difficult, even though the need has been stressed for decades. In this thesis population genetic patterns in continuous environments are described, compared among species, and related to conservation management. The model systems are moose (Alces alces) in Sweden and multiple species in the Baltic Sea, with particular focus on the Northern pike (Esox lucius). The spatial scope of the studies is large, and much focus is dedicated towards comprehensive sampling over large geographic areas. The moose population in Sweden is shown to be divided into two major subpopulations, a northern and a southern one. Both subpopulations show genetic signals of major population bottlenecks, which coincide with known population reductions due to high hunting pressure (Paper I). The Northern pike in the Baltic Sea shows relatively weak, but temporally stable population genetic structure. An isolation by distance pattern suggests that gene flow primarily takes place among neighboring populations, either over shortest waterway distance or along the mainland coast, with island populations acting as stepping stones (Paper III). In a comparative study of seven Baltic Sea species no shared genetic patterns were found, either in terms of genetic divergence among or genetic diversity within geographic regions. These results complicate the incorporation of genetic data into management, because it suggests that no generalization can be made among species in the Baltic Sea, but that species-specific management is needed (Paper II). Over the last 50 years, 61 species in the Baltic Sea have been studied with respect to spatial genetic patterns. For over 20 of these species information of direct relevance for management is available. Relevant information is synthesized into management recommendations (Paper IV). This thesis provides vital information on spatial and temporal genetic structure for a number of ecologically and socio-economically important species. It shows that such information is important to consider species by species and that both local and metapopulation approaches are needed to effectively manage genetic diversity in e.g. moose and pike. Further, it identifies for which organisms in the Baltic Sea genetic information exists, how it can be used, and where important information is lacking. In order to successfully make use of genetic data in management, effective communication channels between academia and policy-makers are needed.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.
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Senatore, Riccardo. "An information theoretic analysis of population codes and neuronal cross-relation." Thesis, University of Manchester, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492068.
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