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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.
1

Assessing the emergency famine relief operation in the 2006 drought intervention in Kenya

Mohammed, Farid Abdulkadir 26 March 2015 (has links)
No description available.
2

Previous Holocaust Experiences Continue to Affect Food Attitudes in Survivors

Sindler, Amy Joyce 27 January 2003 (has links)
A qualitative study was conducted to determine if Holocaust survivors’ food attitudes are influenced by their earlier experiences. The 25 survivor interviewees (14 males, 11 females) ranged in age from 71 to 85 years and resided in Miami-Dade and Broward, Florida counties. Most (56%) were interned in concentration camps during the Holocaust. Interviews were tape-recorded and later transcribed. Results showed earlier experiences influenced food attitudes. The most common themes were: 1) Difficulty throwing food away - even when spoiled; 2) Storing excess food; 3) Craving a certain food; 4) Difficulty standing in line for food; and 5) Anxiety when food is not readily available. Sub-themes included healthy eating and empathy for those currently suffering from hunger. Fourteen (56%) fast for religious holidays, but 7 (28%) said they already had “fasted enough.” Dietitians and others are encouraged to evaluate food service programs to minimize uncomfortable food-related situations for Holocaust survivors.
3

The effect of food deprivation on self determined "thresholds" of hypothalamic self-stimulation.

Silagy, Marilyn Blanche. January 1964 (has links)
Experiments utilizing techniques of ablation, as well as electrical and chemical stimulation, have all implicated the lateral hypothalamus as an area of central importance in the regulation of food intake. Anand and Brobeck (1951) were the first to demonstrate that bilateral lesions placed lateral to the ventromedial hypothalamic nucleus in both rats and cats were consistently associated with the development of a temporary or permanent aphagia (refusal to eat). This finding has been duplicated in various other animal species including birds (Andersson, Fabricus, Svensson & Akerman, 1960: Feldman, Larsson, Dimick, & Leprovsky, 1957) and monkeys (Anand, Dua & Shoenberg, 1955). [...]
4

The effect of food deprivation on self determined "thresholds" of hypothalamic self-stimulation.

Silagy, Marilyn Blanche. January 1964 (has links)
No description available.
5

Effects of Chronic Sleep and Food Deprivation on In Vivo Levels of Prepro-Hypocretin (PPH)

Dunn, Kelly 17 December 2004 (has links)
The hypocretin peptides are two hypothalamic peptides known to be involved in both sleeping and feeding behavior, however their specific roles in these domains are not well understood. The present study sought to determine the effect of chronic (72-hour) sleep deprivation and (48-hour) food deprivation on preprohypocretin (PPH), which is the precursor for the hypocretin peptides. PPH levels were visualized and quantified via in situ hybridization. A three-factor ANOVA ( group x dorsal/ventral x medial/lateral) revealed a significant effect of subregion, specifically dorsal/middle and ventral/medial exhibited elevated PPH levels, however there was no effect of group. A between group one-way ANOVA revealed no effect of group on PPH levels. It is theorized that four possible domains may be responsible for these results: presence of hypothalamic neuronal subpopulations, role of circadian rhythm, role of hypocretins in locomotive behavior and inextricably confounded variables. These are discussed at length.
6

Behavioural effects of food deprivation on red junglefowl (Gallus gallus) and White Leghorn layers

Lind, Jenny January 2007 (has links)
The aim of this study was to examine how food deprivation effects food-related and other behavioural systems of red junglefowl (Gallus gallus) and the domesticated White Leghorn layers. If an animal is denied to perform their natural behaviours, like eating, sleeping or preening, the motivation for the behaviour can increase. Behavioural systems may interact and motivation to perform behaviours may be influenced. After being deprived of a certain need the reaction can become exaggerated or abnormal. Food deprivation is often used in ethology research to motivate animals. The hypothesis in this study was that the chickens would become affected by the food deprivation and reallocate their behaviours. They would get more stressed and frustrated. Domestication effects and sex differences were explored. The birds were tested in four standardized behavioural tests; food consumption test, general behavioural test, open field test and novel object test. The results showed that they foraged and explored more, had less comfort behaviours, and less perching the longer they had been without food. They did not show a higher degree of frustration, stress or aggressive behaviours. There were domestication effects, where the Leghorns seem to have lost some of their ability to respond adaptively to food shortage. Differences between the sexes were found, where the females foraged more and the males were more stressed. The conclusion was that the birds do not get more stressed when food deprived, but they forage and explore more which is a desirable effect of food deprivation used in ethology research.
7

Behavioural effects of food deprivation on red junglefowl (Gallus gallus) and White Leghorn layers

Lind, Jenny January 2007 (has links)
<p>The aim of this study was to examine how food deprivation effects food-related and other behavioural systems of red junglefowl (Gallus gallus) and the domesticated White Leghorn layers. If an animal is denied to perform their natural behaviours, like eating, sleeping or preening, the motivation for the behaviour can increase. Behavioural systems may interact and motivation to perform behaviours may be influenced. After being deprived of a certain need the reaction can become exaggerated or abnormal. Food deprivation is often used in ethology research to motivate animals. The hypothesis in this study was that the chickens would become affected by the food deprivation and reallocate their behaviours. They would get more stressed and frustrated. Domestication effects and sex differences were explored. The birds were tested in four standardized behavioural tests; food consumption test, general behavioural test, open field test and novel object test. The results showed that they foraged and explored more, had less comfort behaviours, and less perching the longer they had been without food. They did not show a higher degree of frustration, stress or aggressive behaviours. There were domestication effects, where the Leghorns seem to have lost some of their ability to respond adaptively to food shortage. Differences between the sexes were found, where the females foraged more and the males were more stressed. The conclusion was that the birds do not get more stressed when food deprived, but they forage and explore more which is a desirable effect of food deprivation used in ethology research.</p>
8

Performance e preferência de imaturos selvagens de Ascia monuste (Godart, 1819) (Lepidoptera, Pieridae) na mudança e na privação de hospedeiros alimentares diferentes / Performance and host preference of Ascia monuste (Lepidoptera, Pieridae) wild immatures in food change and deprivation of different hosts

Santana, Alessandra Figueiredo Kikuda 04 March 2008 (has links)
Lagartas de Ascia monuste (Lepidoptera, Pieridae) são especialistas em Brassicaceae, sendo uma das maiores consumidoras desta família da região Neotropical. No campo, uma grande proporção de lagartas migra para outros hospedeiros e freqüentemente deparam-se com variações nutricionais e espaciais de alimento. O presente trabalho teve como objetivo principal estudar a performance dos imaturos de A. monuste em quatro combinações de alimentações, com hospedeiros alimentares diferentes numa mesma fase ontogenética, utilizando-se três hospedeiros naturais: couve (Brassica oleracea var. acephala) e rúcula (Eruca sativa), e couve e repolho (B. oleracea var. capitata). Estas plantas diferem quanto ao conteúdo de nitrogênio, com couve e rúcula tendo quantidades semelhantes e maiores que o repolho. Além disso, foi avaliado, tanto em campo quanto em laboratório, se a experiência alimentar prévia influencia na escolha de alimento no instar larval subseqüente, e quais seriam os efeitos de um período de privação de 24 horas de alimento, antes da mudança de hospedeiro, sobre a performance do inseto. Apesar de pequenas diferenças digestórias, possivelmente causadas pela adequação às diferenças de nutrientes, o tempo de desenvolvimento não diferiu significativamente entre os tratamentos; houve uma porcentagem de emergência e fecundidade potencial altas. De acordo com os resultados encontrados no presente estudo, rúcula e repolho seriam os hospedeiros de valores nutritivos semelhantes e couve, o hospedeiro de valor nutritivo diferente (e mais adequado para a performance de A. monuste). Pupas originadas de lagartas alimentadas com rúcula e repolho apresentaram, de uma forma geral, menor quantidade de massa e menos oócitos, inclusive quando houve privação alimentar entre os hospedeiros. A preferência alimentar por rúcula, ao invés de couve, e por couve, ao invés de repolho, independente do alimento prévio, mostra que a experiência prévia não determina a escolha por hospedeiros em imaturos em A. monuste. A preferência em campo diferiu daquela encontrada em laboratório. A privação de 24 horas de alimento entre a mudança de hospedeiros não provocou danos adicionais na performance das lagartas alimentadas com couve e rúcula, mas aumentou as taxas de mortalidade dos grupos alimentados com couve e repolho. / Ascia monuste (Lepidoptera, Pieridae) caterpillars are Brassicaceae specialists, being one of the most important comsumers of this plant family in the Neotropical region. In the field, a high proportion of immatures migrates to other hosts in order to develop properly, probably facing some variation in terms of nutritional value and location of their hosts. The main objective of this study was to investigate how the feeding of caterpillars of same ontogenetic phase on different hosts [kale (Brassica oleracea L. var. acephala) and rucola (Eruca sativa L.), and kale and cabbage (Brassica olerace L. var. capitata)], affects the corresponding performance of A. monuste. The hosts above mentioned differ in their nitrogen content: kale and rucola have similar nitrogen quantity, and kale has higher quantity than cabbage. In addition, it was evaluated whether the previous host would influence food choice in subsequent larval instar, in the field and in laboratory, as well as the effects of 24 hours of food deprivation on immature performance before switching the host. Beside few differences caused by host switching, possibly by the differences in nutrient levels, all the feeding tests originated similar performances and viable adults. When the preference was determined by the first caterpillar ingestion, previous experience did not influence host choice: caterpillars chose rucola instead of kale, and kale instead of cabbage, independently of previous host. But, when preference was determined by the total amount of ingested food, previous experience acted as a fagoestimulant in kale and rucola as hosts. It was not possible to detect what determine larval preference in the field. All plants tested were attractive for the caterpillars and the migration may occur for hosts that are close and easier to find. The 24 h food deprivation did not increase the effects of host change, but did present some differences. Rucola and cabbage could be less adequate hosts on final instars, because pupae whose larvae ingested these crucifers presented, in general, less pupal mass and also less oocytes, even when food deprivation does not occured.
9

Development of virtual environments to investigate path integration in mice

Fischer, Lukas January 2015 (has links)
Path integration is the ability to navigate to a goal location without using external cues, thus relying entirely on self-motion information. To do so, two components of a path need to be encoded: orientation and distance. While the ability to estimate distance, called linear path integration, is well established in humans, it is unclear whether rodents are equally capable of doing so and the underlying neural circuit mechanisms are only poorly understood. This thesis discusses the development of a virtual reality system and behavioural task to investigate linear path integration in mice, and the results obtained from experiments carried out with this system. The setup provides full control over visual input while de-correlating vestibular and olfactory signals from location. Manipulations of the translation from physical to virtual movement can thus be used to probe relative influences of motor related and visual signals. Chapter 1 reviews the current literature on path integration and provides a background to the technical setup of the system. Chapter 2 describes the design and construction of the virtual reality system, its individual components and the software created to run experiments. It discusses how 3-d modelling and 3-d printing have successfully been combined to allow rapid development and production of custom components in different materials. Chapter 3 discusses the development of behavioural tasks designed to investigate linear path integration. It shows that by using a simple virtual track design and a carefully monitored food-deprivation regime, mice can be trained to successfully associate a visually indicated location with a reward. Chapter 4 describes behavioural experiments carried out using this virtual linear track. I obtained evidence that mice can estimate the distance to the rewarded zone reliably using path integration strategies. To test whether mice rely on motor information or optic flow, I manipulated the gain between physical movement and virtual movement. My results suggest that mice primarily rely on motor information for linear path integration. In the final chapter the results are discussed in the context of other recent work and areas for further development of the system are identified.
10

Performance e preferência de imaturos selvagens de Ascia monuste (Godart, 1819) (Lepidoptera, Pieridae) na mudança e na privação de hospedeiros alimentares diferentes / Performance and host preference of Ascia monuste (Lepidoptera, Pieridae) wild immatures in food change and deprivation of different hosts

Alessandra Figueiredo Kikuda Santana 04 March 2008 (has links)
Lagartas de Ascia monuste (Lepidoptera, Pieridae) são especialistas em Brassicaceae, sendo uma das maiores consumidoras desta família da região Neotropical. No campo, uma grande proporção de lagartas migra para outros hospedeiros e freqüentemente deparam-se com variações nutricionais e espaciais de alimento. O presente trabalho teve como objetivo principal estudar a performance dos imaturos de A. monuste em quatro combinações de alimentações, com hospedeiros alimentares diferentes numa mesma fase ontogenética, utilizando-se três hospedeiros naturais: couve (Brassica oleracea var. acephala) e rúcula (Eruca sativa), e couve e repolho (B. oleracea var. capitata). Estas plantas diferem quanto ao conteúdo de nitrogênio, com couve e rúcula tendo quantidades semelhantes e maiores que o repolho. Além disso, foi avaliado, tanto em campo quanto em laboratório, se a experiência alimentar prévia influencia na escolha de alimento no instar larval subseqüente, e quais seriam os efeitos de um período de privação de 24 horas de alimento, antes da mudança de hospedeiro, sobre a performance do inseto. Apesar de pequenas diferenças digestórias, possivelmente causadas pela adequação às diferenças de nutrientes, o tempo de desenvolvimento não diferiu significativamente entre os tratamentos; houve uma porcentagem de emergência e fecundidade potencial altas. De acordo com os resultados encontrados no presente estudo, rúcula e repolho seriam os hospedeiros de valores nutritivos semelhantes e couve, o hospedeiro de valor nutritivo diferente (e mais adequado para a performance de A. monuste). Pupas originadas de lagartas alimentadas com rúcula e repolho apresentaram, de uma forma geral, menor quantidade de massa e menos oócitos, inclusive quando houve privação alimentar entre os hospedeiros. A preferência alimentar por rúcula, ao invés de couve, e por couve, ao invés de repolho, independente do alimento prévio, mostra que a experiência prévia não determina a escolha por hospedeiros em imaturos em A. monuste. A preferência em campo diferiu daquela encontrada em laboratório. A privação de 24 horas de alimento entre a mudança de hospedeiros não provocou danos adicionais na performance das lagartas alimentadas com couve e rúcula, mas aumentou as taxas de mortalidade dos grupos alimentados com couve e repolho. / Ascia monuste (Lepidoptera, Pieridae) caterpillars are Brassicaceae specialists, being one of the most important comsumers of this plant family in the Neotropical region. In the field, a high proportion of immatures migrates to other hosts in order to develop properly, probably facing some variation in terms of nutritional value and location of their hosts. The main objective of this study was to investigate how the feeding of caterpillars of same ontogenetic phase on different hosts [kale (Brassica oleracea L. var. acephala) and rucola (Eruca sativa L.), and kale and cabbage (Brassica olerace L. var. capitata)], affects the corresponding performance of A. monuste. The hosts above mentioned differ in their nitrogen content: kale and rucola have similar nitrogen quantity, and kale has higher quantity than cabbage. In addition, it was evaluated whether the previous host would influence food choice in subsequent larval instar, in the field and in laboratory, as well as the effects of 24 hours of food deprivation on immature performance before switching the host. Beside few differences caused by host switching, possibly by the differences in nutrient levels, all the feeding tests originated similar performances and viable adults. When the preference was determined by the first caterpillar ingestion, previous experience did not influence host choice: caterpillars chose rucola instead of kale, and kale instead of cabbage, independently of previous host. But, when preference was determined by the total amount of ingested food, previous experience acted as a fagoestimulant in kale and rucola as hosts. It was not possible to detect what determine larval preference in the field. All plants tested were attractive for the caterpillars and the migration may occur for hosts that are close and easier to find. The 24 h food deprivation did not increase the effects of host change, but did present some differences. Rucola and cabbage could be less adequate hosts on final instars, because pupae whose larvae ingested these crucifers presented, in general, less pupal mass and also less oocytes, even when food deprivation does not occured.

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