937 resultados para target population of environments
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[EN] Because of the extensive migrations of marine turtles through the ocean, many aspects of their biology have been unknown for a long time. However, much information has been recently gained from genetic studies and population monitoring of female turtles at their nesting sites. In contrast, still very little is known on the genetic diversity, population structure and dispersal patterns of the male breeding population, mainly because of the difficulty of capturing and monitoring them at sea. The aim of this study is to assess the genetic patterns of the male breeding population of the loggerhead turtle, Caretta caretta, using a non invasive approach and compare them to the female breeding population.
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Le rapide déclin actuel de la biodiversité est inquiétant et les activités humaines en sont la cause directe. De nombreuses aires protégées ont été mises en place pour contrer cette perte de biodiversité. Afin de maximiser leur efficacité, l’amélioration de la connectivité fonctionnelle entre elles est requise. Les changements climatiques perturbent actuellement les conditions environnementales de façon globale. C’est une menace pour la biodiversité qui n’a pas souvent été intégrée lors de la mise en place des aires protégées, jusqu’à récemment. Le mouvement des espèces, et donc la connectivité fonctionnelle du paysage, est impacté par les changements climatiques et des études ont montré qu’améliorer la connectivité fonctionnelle entre les aires protégées aiderait les espèces à faire face aux impacts des changements climatiques. Ma thèse présente une méthode pour concevoir des réseaux d’aires protégées tout en tenant compte des changements climatiques et de la connectivité fonctionnelle. Mon aire d’étude est la région de la Gaspésie au Québec (Canada). La population en voie de disparition de caribou de la Gaspésie-Atlantique (Rangifer tarandus caribou) a été utilisée comme espèce focale pour définir la connectivité fonctionnelle. Cette petite population subit un déclin continu dû à la prédation et la modification de son habitat, et les changements climatiques pourraient devenir une menace supplémentaire. J’ai d’abord construit un modèle individu-centré spatialement explicite pour expliquer et simuler le mouvement du caribou. J’ai utilisé les données VHF éparses de la population de caribou et une stratégie de modélisation patron-orienté pour paramétrer et sélectionner la meilleure hypothèse de mouvement. Mon meilleur modèle a reproduit la plupart des patrons de mouvement définis avec les données observées. Ce modèle fournit une meilleure compréhension des moteurs du mouvement du caribou de la Gaspésie-Atlantique, ainsi qu’une estimation spatiale de son utilisation du paysage dans la région. J’ai conclu que les données éparses étaient suffisantes pour ajuster un modèle individu-centré lorsqu’utilisé avec une modélisation patron-orienté. Ensuite, j’ai estimé l’impact des changements climatiques et de différentes actions de conservation sur le potentiel de mouvement du caribou. J’ai utilisé le modèle individu-centré pour simuler le mouvement du caribou dans des paysages hypothétiques représentant différents scénarios de changements climatiques et d’actions de conservation. Les actions de conservation représentaient la mise en place de nouvelles aires protégées en Gaspésie, comme définies par le scénario proposé par le gouvernement du Québec, ainsi que la restauration de routes secondaires à l’intérieur des aires protégées. Les impacts des changements climatiques sur la végétation, comme définis dans mes scénarios, ont réduit le potentiel de mouvement du caribou. La restauration des routes était capable d’atténuer ces effets négatifs, contrairement à la mise en place des nouvelles aires protégées. Enfin, j’ai présenté une méthode pour concevoir des réseaux d’aires protégées efficaces et j’ai proposé des nouvelles aires protégées à mettre en place en Gaspésie afin de protéger la biodiversité sur le long terme. J’ai créé de nombreux scénarios de réseaux d’aires protégées en étendant le réseau actuel pour protéger 12% du territoire. J’ai calculé la représentativité écologique et deux mesures de connectivité fonctionnelle sur le long terme pour chaque réseau. Les mesures de connectivité fonctionnelle représentaient l’accès général aux aires protégées pour le caribou de la Gaspésie-Atlantique ainsi que son potentiel de mouvement à l’intérieur. J’ai utilisé les estimations de potentiel de mouvement pour la période de temps actuelle ainsi que pour le futur sous différents scénarios de changements climatiques pour représenter la connectivité fonctionnelle sur le long terme. Le réseau d’aires protégées que j’ai proposé était le scénario qui maximisait le compromis entre les trois caractéristiques de réseau calculées. Dans cette thèse, j’ai expliqué et prédit le mouvement du caribou de la Gaspésie-Atlantique sous différentes conditions environnementales, notamment des paysages impactés par les changements climatiques. Ces résultats m’ont aidée à définir un réseau d’aires protégées à mettre en place en Gaspésie pour protéger le caribou au cours du temps. Je crois que cette thèse apporte de nouvelles connaissances sur le comportement de mouvement du caribou de la Gaspésie-Atlantique, ainsi que sur les actions de conservation qui peuvent être prises en Gaspésie afin d’améliorer la protection du caribou et de celle d’autres espèces. Je crois que la méthode présentée peut être applicable à d’autres écosystèmes aux caractéristiques et besoins similaires.
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Thesis (Master's)--University of Washington, 2016-08
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Thesis (Ph.D.)--University of Washington, 2016-08
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Thesis (Master's)--University of Washington, 2016-08
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Background/Aim: Formaldehyde is classified as carcinogenic to humans, making it a major concern, particularly in occupational settings. Fat-soluble vitamins, such as vitamins A, D, and E, are documented as antigenotoxic and antimutagenic and also correlate with the cell antioxidant potential. This study investigates the influence of these vitamins on genotoxicity biomarkers of formaldehyde-exposed hospital workers. Methods: The target population were hospital workers exposed to formaldehyde (n = 55). Controls were nonexposed individuals (n = 80). The most used genotoxicity biomarkers were the cytokinesis-block micronucleus assay for lymphocytes and the micronucleus test for exfoliated buccal cells. Vitamins A and E were determined by high-performance liquid chromatography with a diode array detector (HPLC-DAD) and vitamin D receptor (VDR) polymorphisms by real-time PCR. Results: Significant correlations were found between genotoxicity biomarkers and between vitamins A and E in controls. Multiple regression showed that vitamin A was significantly associated with a higher mean of nucleoplasmic bridges (p < 0.001), and vitamin E was significantly associated with a decreased frequency of nuclear buds (p = 0.045) in the exposed group. No effect of vitamin D was observed. The VDRBsmI TT genotype carriers presented higher means of all the genotoxicity biomarkers; however, we found no significant associations. Conclusions: The study suggests that vitamin levels may modulate direct signs of genotoxicity.
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RAMOS, Ana Maria de Oliveira et al. Project Pró-Natal: population-based study of perinatal and infant mortality in Natal, Northeast Brazil. Pediatric and Developmental Pathology, v.3, n.1, p.29-35, 2000
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Human standing posture is inherently unstable. The postural control system (PCS), which maintains standing posture, is composed of the sensory, musculoskeletal, and central nervous systems. Together these systems integrate sensory afferents and generate appropriate motor efferents to adjust posture. The PCS maintains the body center of mass (COM) with respect to the base of support while constantly resisting destabilizing forces from internal and external perturbations. To assess the human PCS, postural sway during quiet standing or in response to external perturbation have frequently been examined descriptively. Minimal work has been done to understand and quantify the robustness of the PCS to perturbations. Further, there have been some previous attempts to assess the dynamical systems aspects of the PCS or time evolutionary properties of postural sway. However those techniques can only provide summary information about the PCS characteristics; they cannot provide specific information about or recreate the actual sway behavior. This dissertation consists of two parts: part I, the development of two novel methods to assess the human PCS and, part II, the application of these methods. In study 1, a systematic method for analyzing the human PCS during perturbed stance was developed. A mild impulsive perturbation that subjects can easily experience in their daily lives was used. A measure of robustness of the PCS, 1/MaxSens that was based on the inverse of the sensitivity of the system, was introduced. 1/MaxSens successfully quantified the reduced robustness to external perturbations due to age-related degradation of the PCS. In study 2, a stochastic model was used to better understand the human PCS in terms of dynamical systems aspect. This methodology also has the advantage over previous methods in that the sway behavior is captured in a model that can be used to recreate the random oscillatory properties of the PCS. The invariant density which describes the long-term stationary behavior of the center of pressure (COP) was computed from a Markov chain model that was applied to postural sway data during quiet stance. In order to validate the Invariant Density Analysis (IDA), we applied the technique to COP data from different age groups. We found that older adults swayed farther from the centroid and in more stochastic and random manner than young adults. In part II, the tools developed in part I were applied to both occupational and clinical situations. In study 3, 1/MaxSens and IDA were applied to a population of firefighters to investigate the effects of air bottle configuration (weight and size) and vision on the postural stability of firefighters. We found that both air bottle weight and loss of vision, but not size of air bottle, significantly decreased balance performance and increased fall risk. In study 4, IDA was applied to data collected on 444 community-dwelling elderly adults from the MOBILIZE Boston Study. Four out of five IDA parameters were able to successfully differentiate recurrent fallers from non-fallers, while only five out of 30 more common descriptive and stochastic COP measures could distinguish the two groups. Fall history and the IDA parameter of entropy were found to be significant risk factors for falls. This research proposed a new measure for the PCS robustness (1/MaxSens) and a new technique for quantifying the dynamical systems aspect of the PCS (IDA). These new PCS analysis techniques provide easy and effective ways to assess the PCS in occupational and clinical environments.
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Sardines and other Microfilidae have very important ecological role in marine ecosystems because they are first consumers in marine food chain and they are the main food of valuable species as tuna. So decries in their population will decline fishing of these spices. There are 10 genus of Clupeidae in south of Iran and Sardinella is the one of the most abundant of them. In this study we investigated about morphological and genetically differences in population of 3 species: Sardinella sindensis, Sardinella abella, Dussomieria acuta. About 65 specimens of Sardinella sindensis, 61 specimens of Sardinella albella and 63 specimens of, Dussomieria acuta from three regions of their distribution: Jask (Oman Sea), Qeshm (Hormoz) and Lengeh (Pearsian Gulf) have been collected. Morphological research of their characters and statistical studies were done. To determine the genetically structure of specie's population we sequenced 500 bp of mitochondrial control region. Genetical studies determine meaningful difference in alleles and heterozigosity frequency of Sardinella sindensis. This must be the result of divergence in population of this species. Morphological investigation of Sardinella albella shows the meaningful difference. But detailed studies diffused it. Genetical studies show a meaningful variance in allele and heterosigosity frequency. This may be an aspect of sardine tendency to live in estuaries. Morphological research of Dussomieria acuta in Jask and Lengeh show a meaningful variance in these regions. Such a situation might be result of Monsoon, upwelling and better weather which occur in Oman Sea in spite of Persian Gulf.
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International audience
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International audience
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As the number of fungal pathogen outbreaks become more frequent worldwide across taxa, so have the number of species extirpations and communities persisting with the pathogen. This phenomenon raises questions, such as: “what leads to host extinction during an outbreak?” and “how are hosts persisting once the pathogen establishes?.” But the data on host populations and communities across life stages before and after pathogen arrival rarely exist to answer these questions. Over the past three to four decades, the amphibian-killing fungus Batrachochytrim dendrobatidis (Bd) spread in a wave-like manner across Central America, leading to rapid species extirpations and population declines. I collected data on tadpole and adult amphibians in El Copé, Panama before, during, and after the Bd outbreak to answer these questions. I used Bayesian statistical approaches to account for imperfect host and pathogen detection of marked and unmarked individuals. In the tadpole community, within 11 months of Bds arrival, density and occupancy rapidly declined. Species losses were phylogenetically correlated, with glass frogs disappearing first, and tree frogs and poison-dart frogs remaining. I found that tadpole communities resembled one another more strongly after the outbreak than they did before Bd invasion. I found no tadpoles within 22 months of the outbreak and limited signs of recovery within 10 years. In contrast, at the same site, for a population of male glass frogs, Espadarana prosopleon, I found that 10 years post-outbreak, the population was consistently half its historic abundance, and that the lack of recruits to the population explained why the population had not rebounded, rather than high pathogen-induced mortality. And finally, examining the entire amphibian community, I found high pathogen prevalence, low infection intensities, and high survival rates of uninfected and infected hosts. Bd transmission risk, i.e., the probability a susceptible host becomes infected, did not relate to host density, pathogen prevalence, or infection intensity– Bd transmission risk was uniform across the study area. My results are especially relevant to conservation biologists aiming to predict the future impacts of Bd outbreaks, those trying to manage persisting populations, and those interested in reintroducing species back into wild amphibian communities.
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Repercussions of innovation adoption and diffusion studies have long been imperative to the success of novel introductions. However, perceptions and deductions of current innovation understandings have been changing over time. The paradigm shift from the goods-dominant (G-D) logic to the service-dominant (S-D) logic potentially makes the distinction between product (goods) innovation and service innovation redundant as the S-D logic lens views all innovations as service innovations (Vargo and Lusch, 2004; 2008; Lusch and Nambisan, 2015). From this perspective, product innovations are in essence service innovations, as goods serve as mere distribution mechanisms to deliver service. Nonetheless, the transition to such a broadened and transcending view of service innovation necessitates concurrently a change in the underlying models used to investigate innovation and its subsequent adoption. The present research addresses this gap by engendering a novel model for the most crucial period of service diffusion within the S-D logic context – the post-initial adoption phase, which demarcates an individual’s behavior after the initial adoption decision of a service. As a wellfounded understanding of service diffusion and the complementary innovation adoption still lingers in its infancy, the current study develops a model based on interdisciplinary domains mapping. Here fore, knowledge of the relatively established viral source domain is mapped to the comparatively undetermined target domain of service innovation adoption. To assess the model and test the importance of the explanatory variables, survey data from 750 respondents of a bank in Northern Germany is scrutinized by means of Structural Equation Modeling (SEM). The findings reveal that the continuance intention of a customer, actual usage of the service and the customer influencer value all constitute important postinitial adoption behavior that have meaningful implications for a successful service adoption. Second, the four constructs customer influencer value, organizational commitment, perceived usefulness and service customization are evidenced to have a differential impact on a iv customer’s post-initial adoption behavior. Third, this study indicates that post-initial adoption behavior further underlies the influence of a user’s age and besides that is also provoked by the internal and external environments of service adoption. Finally, this research amalgamates the broad view of service innovation by Nambisan and Lusch (2015) with the findings ensuing this enquiry’s model to arrive at a framework that it both, generalizable and practically applicable. Implications for academia and practitioners are captured along with avenues for future research.
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In this study cross-section data was used to analyze the effect of farmers’ demographic, socioeconomic and institutional setting, market access and physical attributes on the probability and intensity of tissue culture banana (TCB) adoption. The study was carried out between July 2011 and November 2011. Both descriptive (mean, variance, promotions) and regression analysis were used in the analysis. A double hurdle regression model was fitted on the data. Using multistage sampling technique, four counties and eight sub-locations were randomly selected. Using random sampling technique, three hundred and thirty farmers were selected from a list of banana households in the selected sub-locations. The adoption level of tissue culture banana (TCB) was about 32%. The results also revealed that the likelihood of TCB adoption was significantly influenced by: availability of TCB planting material, proportion of banana income to the total farm income, per capita household expenditure and the location of the farmer in Kisii County; while those that significantly influenced the intensity of TCB adoption were: occupation of farmers, family size, labour source, farm size, soil fertility, availability/access of TCB plantlets to farmers, distance to banana market, use of manure in planting banana, access to agricultural extension services and index of TCB/non-TCB banana cultivar attributes which were scored by farmers. Compared to West Pokot County, farmers located in Bungoma County are more significantly and likely to adopt TCB technology. Therefore, the results of the study suggest that the probability of adoption and intensity of the use of TCB should be enhanced. This can be done by taking cognizance of these variables in order to meet the priority needs of the smallholder farmers who were the target group. This would lead to alleviating banana shortage in the region for enhanced food security. Subsequently, actors along the banana value chain are encouraged to target the intervention strategies based on the identified farmer, farm and institutional characteristics for enhanced impact on food provision. Opening up more TCB multiplication centres in different regions will make farmers access the TCB technology for enhanced impact on the target population.
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The calico box crab Hepatus epheliticus is an abundant species from shallow and continental shelf waters of the Atlantic coast of USA and Mexico. Information about population structure and sexual maturity is absent, even though this crab is caught to be used as bait for the octopus fishery in the Campeche Bank, Mexico. In order to achieve such information, a total of 768 individuals were collected from January to March 2010 through baited traps installed in the Yucatan Peninsula, Mexico. Our results showed that sex ratio is biased towards more males than females (1:0.55), contradicting to that reported in other brachyuran crabs. The absence of ovigerous females suggests that they did not enter into the traps during embryogenesis. Males reached a larger maximum size than females (64.0 +/- 6.15 and 58.4 +/- 5.60 mm carapace width, respectively). The general scheme of growth being positive allometric throughout ontogeny of both sexes. Males presented a transition phase from juveniles to adult corresponding to the puberty moult. The estimation of the onset of functional sexual maturity revealed a steady situation for the population, with 21.5 and 13.8% of males and females, respectively, morphologically immature at the time of catch. This study constitutes the first report on population structure and sexual maturity in a population of the calico box crab H. epheliticus.