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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Potencial de genÃtipos de feijÃo-caupi para a produÃÃo de feijÃo verde no norte do estado do Cearà / Potential of genotypes of cowpea for the production of beans in upstate CearÃ

Wener Santos de Almeida 23 August 2013 (has links)
CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / O objetivo deste trabalho foi avaliar o potencial produtivo de genÃtipos de feijÃo-caupi para a produÃÃo de feijÃo-verde, e selecionar o mais adequado para recomendar como cultivar aos produtores do estado do CearÃ. Foram avaliados 16 genÃtipos de feijÃo-caupi em Pentecoste e Baixo AcaraÃ, municÃpios do estado do CearÃ. O delineamento experimental adotado foi o de blocos casualizados com quatro repetiÃÃes. As variÃveis avaliadas foram: comprimento de vagem verde, massa de vagem verde, massa de grÃos de vagem verde, nÃmero de grÃos de vagem verde, massa de 100 grÃos verdes, Ãndice de grÃos verdes, produtividade de vagens verdes e produtividade de grÃos verdes. Realizou-se a correÃÃo de umidade das vagens verdes, sendo esta realizada pelo mÃtodo da embebiÃÃo de Ãgua das vagens e grÃos verdes atà atingir peso constante. As anÃlises de variÃncia univariada e conjunta foram utilizadas para a determinaÃÃo da variabilidade genÃtica entre os genÃtipos avaliados. Os valores mÃdios de cada variÃvel foram agrupados pelo teste de Scott-Knott. As correlaÃÃes foram estimadas por meio da anÃlise de trilha seguindo o modelo proposto por Li, determinando-se os efeitos diretos e indiretos dos componentes da produtividade. Em relaÃÃo à correÃÃo de umidade das vagens e grÃos verdes apÃs a colheita, observou-se que os dados originais apresentam maiores representatividades da massa seca e pressupÃem uma maior precisÃo experimental, sendo a correÃÃo de umidade das vagens e dos grÃos verdes nas condiÃÃes ambientais avaliadas desnecessÃria. Com relaÃÃo à produtividade e seus componentes, observou-se resposta diferenciada dos genÃtipos para todos os caracteres avaliados, demonstrando presenÃa de variabilidade genÃtica. O genÃtipo BRS Tumucumaque apresentou as maiores mÃdias de produtividade de grÃos verdes e componentes primÃrios da produÃÃo em relaÃÃo aos demais genÃtipos em Pentecoste. Jà para o municÃpio de Baixo AcaraÃ, os genÃtipos MNC05-841B-49 e Paulistinha apresentaram as maiores mÃdias de produtividade de grÃos verdes e componentes primÃrios da produÃÃo em relaÃÃo aos demais genÃtipos. Observou-se resposta diferenciada dos genÃtipos nos ambientes, indicando a necessidade da realizaÃÃo da anÃlise de trilha para cada situaÃÃo. A seleÃÃo de genÃtipos mais produtivos em Baixo Acaraà deve ser realizada por meio de seleÃÃo indireta pelo componente massa de grÃos de vagem verde, pelo fato de apresentar maior efeito direto sobre a produtividade, alta herdabilidade e alto coeficiente de variabilidade genÃtico e relaÃÃo CVg/CVe maior que a unidade. Jà a seleÃÃo de genÃtipos mais produtivos em Pentecoste deve ser realizada por meio de seleÃÃo indireta do componente produtividade de vagens verdes, pelo fato de apresentar correlaÃÃo positiva alta com a produtividade de grÃos verdes. / The objective of this study was to evaluate the yield potential of cowpea genotypes for the production of green beans, and select the most appropriate to recommend to farmers how to cultivate the state of CearÃ. We evaluated 16 genotypes of cowpea at Pentecost and Low Acaraà municipalities of CearÃ. The experimental design was a randomized block with four replications. The variables evaluated were: green pod length, green pod mass, bulk grain green pod, number of pod green beans, green beans 100 mass index, green beans, yield of green pods and grain yield green. Was performed to correct moisture from green pods, being performed by the method of soaking water from beans and green beans until constant weight. Analyses of variance were combined and used to determine the genetic variability among the genotypes. Mean values for each variable were grouped by Scott-Knott. Correlations were estimated using path analysis following the model proposed by Li, determining the direct and indirect effects of yield components. Regarding the correction of moisture pods and green beans after harvest, it was observed that the original data have higher representativeness of the dry mass and require increased experimental precision, and correction of moisture from the pods of green beans and environmental conditions evaluated not necessary. With respect to yield and its components, we observed differential response of genotypes for all traits, indicating the presence of genetic variability. The BRS Tumucumaque genotype had the highest average grain yield components and green primary production in comparison with other genotypes at Pentecost. As for the municipality of Low Acaraà genotypes MNC05-841B-49 and Paulistinha had the highest average grain yield components and green primary production in comparison with other genotypes. Observed differential response of genotypes in the environments, indicating the necessity of performing path analysis for each situation. A selection of more productive genotypes in Low Acaraà should be done through indirect selection for grain yield component of green pod, since it presents greater direct effect on productivity, high heritability and high genetic variability coefficient and CVg / CVe greater than unity. Have a selection of more productive genotypes at Pentecost must be performed by indirect selection component yield of green pods, because this has high positive correlation with grain yield green.
22

A Study of the Impact of an Introduced Herbivore on Pollinator-mediated Interactions and Female Fitness in 'Lythrum salicaria'

Russell-Mercier, Jake L. January 2013 (has links)
Herbivory can have many effects on plant fitness, including altering plant-pollinator interactions and sexual reproduction in angiosperms. Pollinator-mediated interactions may be impacted when herbivores alter plant traits, such as floral display size, that can influence pollinator visitation rates, and, ultimately, the reproductive component of plant fitness. Here I describe an investigation into the indirect effects of feeding by beetles released as a biological control agent, Galerucella calmariensis and G. pusilla, on plant-pollinator interactions and reproductive output in the invasive plant Lythrum salicaria L. (purple loosestrife). During the summer of 2011, three treatments (low, ambient and mechanical herbivory) were applied to 105 plants during the pre-flowering period of growth. At the onset of flowering, a series of pollinator observations were conducted over the course of approximately 1.5 weeks. Several aspects of floral display were affected by the herbivory treatments, including increased inflorescence and flower production in the ambient and mechanical herbivory treatments, relative to the low herbivory treatment. Treatment type did not have a significant effect on the number of pollinator foraging bouts, but had marginally significant effects on the number of flowers probed per pollinator foraging bout and per 30-minutes. Moreover, treatment had a significant effect on the number of switches among the inflorescences on a single plant. I discuss the possibility that the differences in pollinator visitation were mediated by differences in the architecture and the size of floral display. There were no detectable differences in fruit or seed production (i.e., female fitness) among treatments. However, as I discuss, differences in pollinator visitation may affect other unmeasured aspects of fitness, such as the level of inbreeding or the number of seeds sired through male function.
23

Aerosol indirect effects in POLDER satellite data and the Laboratoire de Météorologie Dynamique–Zoom (LMDZ) general circulation model

Quaas, Johannes, Boucher, Olivier, Bréon, François-Marie January 2004 (has links)
The POLDER-1 instrument was able to measure aerosol and cloud properties for eight months in 1996–1997. We use these observational data for aerosol concentration (the aerosol index), cloud optical thickness, and cloud droplet effective radius to establish statistical relationships among these parameters in order to analyze the first and second aerosol indirect effects. We also evaluate the representation of these effects as parameterized in the Laboratoire de Météorologie Dynamique–Zoom (LMDZ) general circulation model. We find a decrease in cloud top droplet radius with increasing aerosol index in both the model and the observations. Our results are only slightly changed if the analysis is done at fixed cloud liquid water path (LWP) instead of considering all LWP conditions. We also find a positive correlation between aerosol index and cloud liquid water path, which is particularly pronounced over the Northern Hemisphere midlatitudes. This may be interpreted as observational evidence for the second aerosol indirect effect on a large scale. The model-simulated relationship agrees well with that derived from POLDER data. Model simulations show a rather small change in the two relationships if preindustrial rather than present-day aerosol distributions are used. However, when entirely switching off the second aerosol indirect effect in our model, we find a much steeper slope than we do when including it.
24

Evaluating parameterisations of subgrid-scale variability

Quaas, Johannes, Grützun, Verena, Schemann, Vera, Weber, Torsten 26 November 2015 (has links)
Parameterisations of fractional cloudiness in large-scale atmospheric models rely on information about the subgrid-scale variablity of the total water specific humidity, qt , provided in form of a probability density function (PDF). In this contribution, four different approaches to evaluate such total-water PDFs are discussed: (i) Satellite spectroradiometers with high spatial resolution allow to construct at the scale of model grid boxes a histogram, and subsequently to derive the moments of the PDF, of the vertical integral of qt . This can be compared to the same quantity diagnosed from the model parameterisation. Although the vertical integral mostly focuses on the boundary layer, and involves issues in grid-boxes with orographic variability, it allowed nevertheless in the example presented to pinpoint deficiencies of a model parameterisation. (ii) Assuming a simple PDF shape and saturation within clouds, the simple “critical relative humidity” metric can be derived from infrared sounders and/or cloud lidar in combination with reanalysis data with a vertical resolution. It allows to evaluate the underlying PDF of any cloud scheme, but is sensitive to the assumptions. (iii) Supersites with a combination of ground-based lidar, radar and microwave data provide high-resolution high-quality reference data. In a “virtual reality” framework, we showed, however, that it is difficult to evaluate higher moments of a spatial PDF with this temporally-varying data. (iv) From a hierarchy of models from general circulation models to direct numerical simulations, we find that the variance of the qt follows a power-law scaling with an exponent of about -2. This information is very useful to improve the parameterisations.
25

A New Perspective on Giving-Up Density Experiments and the Landscape of Fear

McMahon, Jordan D 04 May 2018 (has links)
Non-consumptive effects that predators have on prey are important to ecosystems. The perceived risk of predation can alter feeding behavior. Giving-up density (GUD) experiments have been a foundational method to evaluate perceived predation risk, but rely on the assumption that food preferences are absolute. However, nutritional preferences are context dependent and can change with risk. In my first chapter, I used spiders and grasshoppers to test the hypothesis that covariance in nutritional preferences and risk may confound the interpretation of GUD experiments. My results demonstrate that predation risk and nutritional preferences covary and can confound interpretation of GUD experiments. In my second chapter, I use a behavioral observation experiment to further explore non-consumptive effects, as well as the movement of prey in response to predation risk.
26

Antecedents of Parental Psychological Control: A Test of Bowen's Theory

Bradshaw, Spencer D. 20 April 2011 (has links) (PDF)
Parental psychological control has been found to be associated with both internalized and externalized problems for youth and adolescents. Research contributing to an understanding of the possible antecedents of parental psychological control is both limited and of need; specifically regarding parents' psychological attributes. This study sample included 323 two-parent families and an identified target child from each family. Bowen's theory of family systems, [chronic] stress, and differentiation of self and its relation to parental psychological control was examined. Differentiation of self was hypothesized to mediate the relationship between chronic stress and parental psychological control. Differentiation was conceptualized and measured using two subscales assessing emotional reactivity and emotional cutoff. Fathers and mothers were included in the same model to assess for potential partner influences as well possible gender differences. Parental age, parental education, and family income were also included as control variables. Study analyses included bivariate correlations, independent T-tests, and structural path models; all based on study variables constructed in a structural equation measurement model. To test for mediation by differentiation of self, an initial structural model examining the relationship between levels of parental chronic stress and parental psychological control was utilized. Only paternal chronic stress and paternal education predicted child-reported levels of parental psychological control. Parent-reported levels of differentiation of self, when included in a structural path model, did not mediate the relationship between chronic stress and psychological control but did have a significant indirect effect on this relationship. Both maternal and paternal chronic stress significantly predicted individual parental levels of emotional reactivity and emotional cutoff. Systemically, maternal levels of emotional cutoff predicted paternal levels of parental psychological control and paternal levels of emotional reactivity predicted maternal levels of parental psychological control. No control variables other than paternal education had a salient, significant, or interpretable effect on endogenous study variables (differentiation of self and parental psychological control). Paternal and maternal levels of emotional reactivity appeared to partially mediate the relationship between paternal education and maternal psychological control. Interpretation for results, study limitations and future directions, and clinical implications are discussed.
27

Indirect Food Web Interactions: Sea Otter Predation Linked to Invasion Success in a Marine Fouling Community

Jenkins, Maggie F 01 December 2018 (has links) (PDF)
Humans have caused grave ecological and economic damage worldwide through the introduction of invasive species. Understanding the factors that influence community susceptibility to invasion are important for controlling further spread of invasive species. Predators have been found to provide biotic resistance to invasion in both terrestrial and marine systems. However, predators can also have the opposite effect, and facilitate invasion. Therefore, recovery or expansion of native predators could facilitate the spread of invasive species. Needles et al. (2015) demonstrated that the threatened southern sea otter (Enhydra lutris nereis) facilitated the invasion of an exotic bryozoan, Watersipora subatra. However, the underlying mechanism was not fully understood. We tested the hypothesis that sea otter predation on Romaleon antennarium crabs indirectly facilitated the abundance of W. subatra. To do this, we collected weekly data on sea otter foraging and quantified the abundance of crabs in the sea otter diet. We also conducted a caging experiment, where we experimentally manipulated crab densities and limited otter access using exclusion cages on pier pilings in Morro Bay, CA. We used photoQuad image processing software to calculate the abundance of W. subatra on PVC panels within each treatment group. We found that crabs were the second most abundant prey item in Morro Bay, comprising 25.1% of the otter diet. Through the caging experiment, we found that W. subatra abundance significantly increased as crab densities decreased. Our results indicated that sea otters indirectly facilitated the invasion of W. subatra by reducing R. antennarium crab densities and sizes. Removal of crabs may release W. subatra from the disturbance caused by crab foraging behavior. Understanding the impacts of top predators in invaded ecosystems has important management implications, as recovery of predator populations could unintentionally benefit some non-native species. Therefore, management should focus first on prevention and second on early detection and eradication of invasive species likely to benefit from predator recovery.
28

Mamíferos de maior porte em paisagens tropicais alteradas: seu papel em cascatas tróficas e fatores que determinam sua distribuição / Large mammals in altered tropical forest landscapes: their role in trophic cascade and factors that determine their distribution

Oliveira, Gustavo de 17 November 2011 (has links)
Nesta dissertação investigamos o papel dos mamíferos em cascatas tróficas nas florestas tropicais, e os efeitos da configuração espacial e qualidade do habitat assim como das atividades humanas atuais sobre a distribuição de mamíferos de maior porte em uma paisagem rural de Mata Atlântica. No primeiro capítulo, através de uma revisão da literatura sumarizamos e avaliamos a evidência empírica de que mamíferos estão envolvidos em cascatas tróficas em florestas tropicais com o objetivo de indicar os avanços, os problemas e os desafios nessa área. Poucos estudos empíricos e conceituais foram encontrados na literatura, todos realizados nas últimas três décadas, enquanto que a maioria dos estudos empíricos foi realizada nos Neotrópicos. Grande parte das hipóteses relacionadas a cascatas tróficas foi apenas proposta, e considera o homem como predador de topo. Além da maior parte das variáveis quantificadas não serem adequadas para demonstrar efeitos em cascata, a escala temporal da maioria dos estudos revisados foi curta para acessar estes efeitos sobre a comunidade de plantas que contém espécies longevas. Nenhuma hipótese abordou o efeito dos predadores de topo sobre as populações de presas pequenas via o controle da densidade e distribuição de mesopredadores. A maioria das hipóteses que encontramos na literatura se refere a outros efeitos indiretos causados por mamíferos, em particular através da dispersão de sementes e da disponibilização de nutrientes via fezes. Dessa maneira, demonstramos que o termo \"cascata trófica\" tem sido utilizado amplamente, englobando outros efeitos indiretos que se propagam via outras interações que não tróficas, e que a evidência empírica disponível até o momento de que mamíferos desencadeiam cascatas tróficas em florestas tropicais é pequena. No segundo capítulo, através da amostragem de 23 remanescentes florestais e do uso de modelos de ocupação e da abordagem de seleção de modelos, investigamos como fatores associados à configuração espacial e qualidade do habitat e a outras atividades humanas em andamento interagem e condicionam a distribuição de mamíferos terrestres de maior porte em paisagens intensamente modificadas pelo homem. A assembléia de mamíferos de maior porte encontrada na paisagem estudada é simplificada e dominada por mamíferos silvestres generalistas de médio porte, sugerindo que o controle de mesopredadores e a regeneração das florestas podem estar comprometidos. Os resultados também sugerem que: (1) a distribuição de mamíferos de maior porte deve ser condicionada mais por fatores associados à configuração espacial do que à qualidade do habitat florestal; (2) as atividades humanas atuais são tão ou mais importantes que a configuração espacial e a qualidade do habitat para a maioria das espécies. O tamanho dos fragmentos e a distância a rodovias, entre os fatores associados à configuração espacial, e a caça e a presença do cachorro doméstico, entre as atividades humanas atuais, foram particularmente importantes para a distribuição das espécies de mamíferos de maior porte. A relevância das atividades humanas em andamento sugere que estratégias de manejo que foquem em mudanças na atitude da população humana, através de programas de conscientização e educação, podem ter resultados significativos em termos da persistência de populações de mamíferos em paisagens rurais. / In this dissertation we investigated the role of large mammals in trophic cascades in tropical forests, and the effects of habitat configuration and quality as well as of current human activities on the distribution of large mammals in a rural Atlantic forest landscape. In the first chapter, through a literature review we summarized and evaluated the empirical evidence that mammals are involved in trophic cascades in tropical forest, with the aim of highlighting the progress, problems and challenges in this area. Few conceptual and empirical studies were found in the literature, all of which were performed in the last three decades, while most of the empirical studies were developed in the Neotropics. Most of the hypotheses related to trophic cascades were only proposed and not tested, and considered humans as top predators. Not only most of the quantified variables were not appropriate to demonstrate cascading effects, but also the temporal scale of most studies was short to detect these effects on plant communities composed of long-lived species. We did not find hypotheses addressing the effect of top predators on the populations of small prey through the control of mesopredator density and distribution. Most hypotheses in the reviewed literature refer to other indirect effects played by mammals, especially through seed dispersal and nutrient allocation via feaces. Thus, we demonstrate that the term \"trophic cascade\" has been used widely, encompassing other indirect effects that propagate through other, non-throphic interactions, and that the empirical evidence available so far that mammals are drivers of trophic cascades in tropical forest is weak. In the second chapter, through the sampling of 23 forest fragments and using occupancy models and a model selection approach, we investigated how factors associated with habitat configuration and quality and with other current human activities interact to define the distribution of terrestrial large mammals in human-modified landscapes. The large mammal assemblage from the studied landscape is impoverished and dominated by medium-sized generalist species, suggesting that both the control of mesopredators and forest regeneration may be compromised. Our results also suggest that: (1) the distribution of large mammals is determined mainly by aspects of habitat configuration rather than by aspects of habitat quality, and (2) current human activities are equally or more important than habitat configuration and quality for most of the species. Fragment size and distance to roads, among the factors associated with habitat configuration, and hunting pressure and domestic dog presence, among those associated with current human activities, were particularly important to the distribution of large mammal species. The relevance of current human activities suggests that management strategies that focus on changing people attitudes, through programs of education, can have significant results in terms of the persistence of mammal populations in rural landscapes.
29

Social Support and Treatment Adherence in Fibromyalgia: Indirect effects of Depressive Symptoms

Montgomery, M., Brooks, Byron D., Sirois, Fuschia M., Hirsch, Jameson 01 November 2016 (has links)
No description available.
30

Health-Related Quality of Life in Fibromyalgia: Indirect Effects of Optimism, Pessimism and Treatment Adherence

Hirsch, Jameson K., Brooks, Byron D., Sirois, Fuschia M., Toussaint, L., Offenbaecher, M., Kohls, Niko 29 July 2016 (has links)
No description available.

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