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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.
11

Should I stay or should I go? Complex environments drive the developmental plasticity of flight capacity and flight-related tradeoffs

Glass, Jordan R. 01 January 2018 (has links)
Animals must balance multiple, fitness-related traits in environments that are complex and characterized by co-varying factors, such as co-variation in temperature and food availability. Thus, experiments manipulating multiple environmental factors provide valuable insight into the role of the environment in shaping not only important traits (e.g., dispersal capacity or reproduction), but also trait-trait interactions (e.g., trade-offs between traits). We employed a multi-factorial design to manipulate variation in temperature (constant 28°C vs. 28±5°C daily cycle) and food availability (unlimited vs. intermittent access) throughout development in the sand field cricket, Gryllus firmus. We found that fitness-related, life-history traits and trait trade-offs can be developmentally plastic in response to variation in temperature and food availability. Variability in temperature and food availability influenced development, growth, body size, reproductive investment, and/or flight capacity, and food availability also affected survival to adulthood. Further, both constant temperature and unlimited food availability promoted investment into key components of somatic and reproductive tissues while reducing investment into flight capacity. We develop an experimental and statistical framework to reveal shifts in correlative patterns of investment into different life-history traits. This approach can be applied to a range of animal systems to investigate how environmental complexity influences traits and trait trade-offs.
12

Disponibilidade domiciliar de alimentos orgânicos no Brasil / Household availability of organic food in Brazil

Mooz, Edinéia Dotti 09 October 2012 (has links)
A busca por alimentos provenientes de sistemas de produção sustentáveis, como por exemplo, os métodos orgânicos de produção é uma tendência que vem se fortalecendo mundialmente. Mudanças nos hábitos alimentares têm sido observadas, revelando a complexidade dos modelos de consumo e de seus fatores determinantes. Sendo assim, este estudo teve por objetivo descrever a disponibilidade domiciliar de alimentos orgânicos no Brasil. Utilizou-se como base de dados informações contidas na Pesquisa de Orçamentos Familiares (POF 2008- 2009), realizada pelo Instituto Brasileiro de Geografia e Estatística (IBGE) sobre aquisições de alimentos e bebidas orgânicos. Os resultados revelam comportamentos distintos na aquisição de alimentos orgânicos entre os brasileiros, quando são discriminados de acordo com as regiões e situação do domicílio (urbano ou rural). Os valores de disponibilidade (média) domiciliar foram superiores entre as famílias residentes nas áreas rurais, notadamente entre as regiões Sul e Centro- Oeste. Nota-se a relação existente entre as condições socioculturais que privilegia a perspectiva ligada à renda, havendo tendência de aumento sistemático de alimentos orgânicos, conforme ocorre crescimento dos rendimentos. Os resultados revelam ainda que quanto menor o número de moradores por domicílio, independente da região, maior a disponibilidade alimentar de orgânicos. Em relação aos grupos alimentares, merece destaque a maior participação do grupo dos laticínios, principalmente entre as famílias residentes nas áreas rurais. Os dados relativos à disponibilidade per capita de energia e participação dos macronutrientes e micronutrientes oriunda dos alimentos orgânicos no Valor Energético Total - VET revelou reduzida contribuição para a totalidade das regiões brasileiras. Quanto às características sociodemográficas das famílias, verifica-se que com o aumento da renda registra-se crescimento na disponibilidade de orgânicos nos domicílios com chefe/responsável do sexo feminino. A maior propensão ao consumo é verificada entre pessoas mais velhas (60 anos ou mais) e com nível de escolaridade superior incompleto. Paralelamente, verificou-se a reduzida quantidade média disponível para a totalidade das famílias brasileiras. / The search for food from sustainable production systems, for example, the organic methods of production, is a trend which rises worldwide. Changes in dietary habits had been observed, showing the complexity of consumption patterns and their corresponding determinant factors. Thus, the aim of this study was to report the household availability of organic food in Brazil. This work was based on information available on Family Budget Research (POF 2008-2009), carried out by the Brazilian Institute of Geography and Statistics (IBGE) about food acquisition for household consumption. The results showed distinct behavior regarding organic food acquisition between Brazilians, which are discriminated accordingly with different regions and household situation (rural or urban). The household availability values (mean) was higher between families located in rural regions, remarkably between South and Middle-West regions. It can be observed a relationship between socio-cultural conditions which allows the perspectives related to income, with systematic rising trend of organic food, when income growth occurs. Also, the results suggested that as lower the numbers of dwellers, independent of region, the household availability of organic foods are increased. Regarding the dietary groups, more emphasis was given about the major contribution of dairy group, mainly within family household in rural areas. Data related to per capita availability of energy and contribution of macronutrients and micronutrients derived from organic food on Total Energy Value showed reduced contribution for totality of the Brazilian regions. About the family socio-demographic features, it was observed an increasing income promoted by a rising availability in households which are headed by women. The major consumption propensity was verified between elderly individuals (60 years old or more) and with incomplete higher education. In addition, it was found the reduced average amount available for totality of Brazilian families.
13

Local food availability, diet and obesity : development and empirical testing of a complex theory

Penney, Tarra Lynn January 2017 (has links)
Individuals with poor quality diets face an increased risk of developing a range of chronic diseases. Aspects of the local food environment, including food availability, have been linked to less healthy diets and increased body weight in adults. However, there is limited theory development to guide the synthesis of empirical studies or the design and evaluation of intervention strategies. Therefore, this dissertation sought to 1) develop a theory of change for unpacking the association between local food availability, diet quality and weight status through identifying hypothesized pathways of influence; and 2) test identified mechanisms using nationally representative data for adults across the United Kingdom and England. Firstly, a systematic review and realist synthesis were used to generate a novel theory of change for food availability, diet and obesity. This involved integration of tacit knowledge from an expert panel with evidence from a range of published food availability interventions. The resulting theory suggested that the influence of food availability on diet and weight status involves a complex set of pathways. Including the importance of understanding the link between the adoption of, and exposure to, different types of food outlets and the alignment of these factors with the preferences and needs of people of varying socioeconomic position (SEP). Thus, use of different away-from-home food outlets (i.e. fast food, restaurant and café) were examined in adults from the National Diet and Nutrition Survey showing that only use of fast food outlets (but not restaurants or cafés) was associated with poor diet quality and obesity, after accounting for SEP. Next, given the potential importance of exposure to the density of food outlets in their use, the same types of away-from-home food outlets were examined in a cross-sectional spatial study of adults from the first wave of the UK Household Longitudinal Study (UKHLS). This analysis showed that again, regardless of individual SEP, the density of fast food outlets around the home was positively associated with away-from-home food spending and obesity, while the density of restaurants was negatively associated with obesity and no link to the density of cafés. Lastly, preliminary longitudinal analysis using adults from five waves of the UKHLS explored the utility of residential relocation as a means of examining the effect of a change in exposure to away-from-home food outlet density on diet and obesity. Results suggest that relocation can lead to substantial change in food outlet exposures; however, relocation is also accompanied by changes in a variety of demographic and socioeconomic circumstances. Collectively, this work demonstrates that theory development and empirical testing can provide a solid conceptual foundation to improve our understanding of how food availability influences unhealthy diet and obesity, for different groups of people and across a range of circumstances. The application of this systematic approach could lead to a more nuanced view of mechanisms of action and thereby more effectively address complex public health problems.
14

Home Food Availability, Dietary Intake and Child Weight Status

Barot, Manasi 01 May 2011 (has links)
Background: Childhood obesity is a critical public health problem. There is a crucial need to identify environmental factors that either encourage or prevent obesogenic behaviors. The home food environment is one of the primary environments in which children are exposed to food. Therefore, it is crucial to study how the home food availability influences dietary intake and weight status. Objective: This study examines parental report of household food availability of fruits, vegetables, and milk, and its association with child weight status and child dietary intake of these foods. Methods: This is a cross-sectional study, based on surveys from 489 students in grades 3-12 their parents in 2009. Child participants were Destination ImagiNation® finalists. Child data collection included surveys based on the Youth Risk Surveillance Survey and anthropometric measurements of height and weight used to calculate child z-BMI. Parents self-reported their heights and weights and home food availability. Descriptive statistics were conducted and multiple linear regression was used to predict whether or not a relationship existed between home food availability, child weight status, and dietary intake of fruits, vegetables, and milk. Results: Overall, 12.5% of participants were overweight and 6.7% were obese. Approximately26% of participants consumed 5 or more servings of fruits and vegetables per day and 17% consumed 3 or more glasses of milk per day. However, a no significant relationship was found between home availability of fruits, vegetables, and milk and the reported intake of these foods. Although a significant association was also found between parent and child weight status, no significant association was found between home food availability and child weight status. Conclusions: Compared to national data, a larger proportion of this sample was classified as normal weight and consumed the recommended intake of fruits and vegetables and milk. Parents reported high availability of fruits, vegetables, and milk products. However, no significance was found between the reported availability of these foods and weight status or dietary intake of fruits, vegetables, or milk.
15

Effects of Tree Species Composition and Foraging Effort on the Productivity of Golden-Cheeked Warblers

Marshall, Mike E. 2011 May 1900 (has links)
The concept of habitat quality is fundamental to the study of ecology, and ecologists have long recognized the importance of vegetation structure and composition in the assessment of wildlife habitat. Vegetative characteristics affect productivity in birds for a variety of reasons (e.g., predator assemblages, nesting sites, song perches, food availability). I investigated the relationship between habitat quality and prey availability and the effect these parameters have on reproductive success in golden-cheeked warblers (Dendroica chrysoparia). My objectives were to 1) determine any differences in pairing and fledging success of warbler territories within two ecosites exhibiting two distinctive tree species composition 2) explore the relationship between tree species composition, arthropod density, and foraging effort, and the effect these parameters have on reproductive success in golden-cheeked warblers and 3) investigate the connection between preferred foraging substrates and changes in arthropod abundance within golden-cheeked warbler territories throughout the breeding season. I mapped individual warbler territories and searched for fledglings, observed foraging behavior, and collected arthropods in each territory to determine productivity, foraging effort, and food availability. I conducted these methods over two seasons in juniper-oak woodlands on Fort Hood, north-central Texas within 347 territories of two vegetative types: those marked by the predominance of post oak (Quercus stellata) and those marked by the predominance of Texas oak (Quercus buckleyi). Pairing and fledging success of territories differed substantially between the two vegetative types. Movement rates differed considerably between the two vegetative types, indicating a difference in prey encounter rate. Foraging data indicated a clear switch in preferred foraging substrates from oak species early in the breeding season, to Ashe juniper (Juniperus ashei) in mid-May. Arthropod sampling revealed a correlation between preferred foraging substrates and arthropod density. Results suggested that Texas oak was an important foraging substrate for golden-cheeked warblers, and territories that lack this tree species generally did not succeed in fledging young. My study can be used to indicate areas that should be targeted for conservation by local, state, and federal government because they provide high quality habitat based on warbler productivity.
16

Gaining women's views on household food security in Wote Sublocation, Kenya

Mulandi, Bernice N. January 2007 (has links)
Thesis (M.A.)--Miami University, Dept. of Geography, 2007. / Title from first page of PDF document. Includes bibliographical references (p. 56-60).
17

A Quantitative Analysis of the Influence of Food Availability on Obesity in the United States

Reeser, Alexander B 01 January 2016 (has links)
PURPOSE: This study is a quantitative analysis of the relationship between obesity and food availability in the United States. A vast amount of literature has been produced examining various food and socioeconomic variables for their effect on obesity rates; however, this is the first research project to use the USDA’s Food Environment Atlas in a nationwide quantitative study. METHODS: This study uses multivariate statistical analysis to study the effect of 24 variables identified in the 2015 USDA Food Environment Atlas on county-wide obesity rates. The primary regression of concern looks specifically at the effect five food availability variables (grocery stores, specialty food stores, SNAP stores, supercenters, and convenience stores) have on obesity rates. RESULTS: Grocery store and specialty food store density is negatively correlated to percent countywide obesity, while supercenter and SNAP store density is positively correlated to percent obesity. Convenience store density had virtually no effect on percent obesity. Potentially confounding variables such as density of recreational facilities and farmers’ markets were also negatively correlated with obesity. Additionally, density of fast-food and full-service restaurants were negatively correlated with obesity, while perpetual poverty was positively correlated to percent obesity. CONCLUSION: The analyses presented in this study suggest that greater availability of grocery stores and specialty food stores may help to curb rising obesity rates. Policy recommendation and considerations based on the results are discussed and explored for their potential utility in addressing the obesity epidemic confronting the United States.
18

Effects of supplementary feeding on the body condition and breeding success of released pheasants

Draycott, R. A. (Roger A. H.) 11 November 2002 (has links)
Abstract The breeding success of released pheasants (Phasianus colchicus) is poor compared with wild ones in Great Britain. Many factors have been cited as possible causes of poor breeding success, including reduced hen condition in the nesting season. The aims of this study were to determine whether reduced body condition due to an inadequate diet contributes to poor breeding success of released pheasants and to demonstrate experimentally the impact of supplementary feeding on their body condition and breeding success. A series of 6 studies of food availability, diet, body condition and breeding success of pheasants was conducted in Britain between 1994 and 2000 to study these questions. Spring diet and food availability were assessed in a multi-site study. Grains and seeds are important dietary components, but their availability to pheasants and their occurrence in the diet was low on all sites during spring. Grains were only a significant component in the diet on sites where supplementary feeding continued into spring. A spring survey of hen pheasant body condition on 21 sites revealed that fat reserves were higher on sites with spring supplementary feeding compared with sites which ceased feeding at the end of the shooting season (1st February). Further, it was demonstrated experimentally that continuing feeding into spring enabled hens to maintain fat reserves at their winter levels, whereas fat reserves of hens in unsupplemented areas were reduced by up to 50%. Supplementary feeding did not improve survival of hens through the spring, but the pre-breeding density of territorial cocks and hens was increased. Feeding did not significantly influence measured productivity parameters except for aspects of re-nesting ability which were improved by feeding. Overall, the densities of young birds observed during autumn counts were twice as high in plots which had been provided with supplementary grain in the previous spring than in unfed plots. Although population densities of pheasants were positively influenced by supplementary feeding, breeding success was still lower than that of wild birds. Clearly, there are behavioural and physiological deficiencies which pre-dispose released pheasants to poor performance in the wild. Habitat deficiencies other than adult food availability are likely to be important too; in particular, the quality of brood rearing habitat which influences chick survival. However, the results of this study contribute to our knowledge of the ecology and management of released pheasants and it is recommended that spring feeding should be conducted routinely by game managers to enable released hens to maintain body condition and maximise their breeding potential.
19

Disponibilidade domiciliar de alimentos orgânicos no Brasil / Household availability of organic food in Brazil

Edinéia Dotti Mooz 09 October 2012 (has links)
A busca por alimentos provenientes de sistemas de produção sustentáveis, como por exemplo, os métodos orgânicos de produção é uma tendência que vem se fortalecendo mundialmente. Mudanças nos hábitos alimentares têm sido observadas, revelando a complexidade dos modelos de consumo e de seus fatores determinantes. Sendo assim, este estudo teve por objetivo descrever a disponibilidade domiciliar de alimentos orgânicos no Brasil. Utilizou-se como base de dados informações contidas na Pesquisa de Orçamentos Familiares (POF 2008- 2009), realizada pelo Instituto Brasileiro de Geografia e Estatística (IBGE) sobre aquisições de alimentos e bebidas orgânicos. Os resultados revelam comportamentos distintos na aquisição de alimentos orgânicos entre os brasileiros, quando são discriminados de acordo com as regiões e situação do domicílio (urbano ou rural). Os valores de disponibilidade (média) domiciliar foram superiores entre as famílias residentes nas áreas rurais, notadamente entre as regiões Sul e Centro- Oeste. Nota-se a relação existente entre as condições socioculturais que privilegia a perspectiva ligada à renda, havendo tendência de aumento sistemático de alimentos orgânicos, conforme ocorre crescimento dos rendimentos. Os resultados revelam ainda que quanto menor o número de moradores por domicílio, independente da região, maior a disponibilidade alimentar de orgânicos. Em relação aos grupos alimentares, merece destaque a maior participação do grupo dos laticínios, principalmente entre as famílias residentes nas áreas rurais. Os dados relativos à disponibilidade per capita de energia e participação dos macronutrientes e micronutrientes oriunda dos alimentos orgânicos no Valor Energético Total - VET revelou reduzida contribuição para a totalidade das regiões brasileiras. Quanto às características sociodemográficas das famílias, verifica-se que com o aumento da renda registra-se crescimento na disponibilidade de orgânicos nos domicílios com chefe/responsável do sexo feminino. A maior propensão ao consumo é verificada entre pessoas mais velhas (60 anos ou mais) e com nível de escolaridade superior incompleto. Paralelamente, verificou-se a reduzida quantidade média disponível para a totalidade das famílias brasileiras. / The search for food from sustainable production systems, for example, the organic methods of production, is a trend which rises worldwide. Changes in dietary habits had been observed, showing the complexity of consumption patterns and their corresponding determinant factors. Thus, the aim of this study was to report the household availability of organic food in Brazil. This work was based on information available on Family Budget Research (POF 2008-2009), carried out by the Brazilian Institute of Geography and Statistics (IBGE) about food acquisition for household consumption. The results showed distinct behavior regarding organic food acquisition between Brazilians, which are discriminated accordingly with different regions and household situation (rural or urban). The household availability values (mean) was higher between families located in rural regions, remarkably between South and Middle-West regions. It can be observed a relationship between socio-cultural conditions which allows the perspectives related to income, with systematic rising trend of organic food, when income growth occurs. Also, the results suggested that as lower the numbers of dwellers, independent of region, the household availability of organic foods are increased. Regarding the dietary groups, more emphasis was given about the major contribution of dairy group, mainly within family household in rural areas. Data related to per capita availability of energy and contribution of macronutrients and micronutrients derived from organic food on Total Energy Value showed reduced contribution for totality of the Brazilian regions. About the family socio-demographic features, it was observed an increasing income promoted by a rising availability in households which are headed by women. The major consumption propensity was verified between elderly individuals (60 years old or more) and with incomplete higher education. In addition, it was found the reduced average amount available for totality of Brazilian families.
20

Availability, Density, Variety, and Distribution of Street Food Stands and Street Foods Across a Mexican City: An Assessment Using the Street Food Stand Assessment Tool

January 2020 (has links)
abstract: Background. Street food stands (SFS) are common ways in which people in Mexico access food, having been a part of the environment and culture of Mexican food for generations. However, no studies have used a validated assessment tool to reliably measure food and beverage availability at a variety of SFS. Nor have the availability, density, variety, and distribution of SFS and street foods and beverages been assessed across neighborhood income levels.Objective: This dissertation’s goal was to decrease gaps in knowledge about the role SFS may play in food availability in the Mexican food environment. Methods: Survey design and ethnographic field methods were used to develop, test, and validate the Street Food Stand Assessment Tool (SFSAT). Geographic information system and ground-truthing methods were used to identify a sample of street segments across 20 neighborhoods representing low-, middle- and high-income neighborhoods in Mexico City on which to assess the availability, density, variety, and distribution of SFS and the foods and beverages sold at these food venues using the SFSAT. Results: A sample of 391 SFS were assessed across 791 street segments. Results showed that SFS were found in all neighborhoods. Contrary to the initial hypothesis, most SFS were found in middle-income neighborhoods. While the availability of street foods and beverages was higher in middle-income neighborhoods, the variety was less consistent: fruit/vegetable variety was high in high-income neighborhoods whereas processed snack variety was higher in low-income neighborhoods. SFS were most often distributed near homes, transportation centers, and worksites across the three neighborhood income levels. Conclusion: This study bridged the gap in knowledge about the availability, density, variety, and distribution of SFS and products sold at these sources of food by using an assessment tool that was developed, tested, and validated specifically for SFS. The findings showed that SFS were found across all neighborhoods. Furthermore, results also suggested that SFS can be a source of healthy food items. Additional studies are needed to understand the relationship between SFS availability, food consumption, and health outcomes in the Mexican population. / Dissertation/Thesis / Doctoral Dissertation Anthropology 2020

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