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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

An examination of the role of associative learning and spatial memory in foraging in two species of bear (Family-Ursidae)

Tarou, Loraine Rybiski, January 2003 (has links) (PDF)
Thesis (Ph. D.)--School of Psychology, Georgia Institute of Technology, 2004. Directed by M. Jackson Marr. / Includes bibliographical references (leaves 290-315).
2

Baylisascaris transfuga in captive and free-ranging populations of bears (Family: Ursidae)

Schaul, Jordan. January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Full text release at OhioLINK's ETD Center delayed at author's request
3

Adnotationes ad ursini generis osteologiam

Grasenick, Elias Robert, January 1900 (has links)
Inaug.-diss.--Halle. / Vita.
4

An examination of the role of associative learning and spatial memory in foraging in two species of bear (Family-Ursidae)

Tarou, Loraine Rybiski 01 December 2003 (has links)
No description available.
5

Genetic studies of North American bear populations using microsatellites

Paetkau, David Henry, January 1997 (has links) (PDF)
Thesis (Ph. D.)--University of Alberta, 1997. / Includes bibliographical references.
6

Relationships between activity patterns and foraging strategies of Yellowstone grizzly bears

Harting, Albert L. January 1985 (has links)
Thesis (M.S.)--Montana State University, 1985. / Cover title. "March 1985." Includes bibliographical references (p. 89-94).
7

Evaluation of indicators of stress in populations of polar bears (Ursus maritimus) and grizzly bears (Ursus arctos)

Hamilton, Jason 07 January 2008 (has links)
Grizzly and polar bears are both species at the top of the food chain in their respective ecosystems, and as such are indicative of the overall health of the ecosystem. Presently there is little data regarding the stress status of these animals. The development of reliable indicators of stress is important as both species face rapid environmental change. Polar bears from Hudson’s Bay (Ontario, Canada) and grizzly bears from Alberta, Canada, were anaesthetized and blood samples retrieved. Samples were assayed for changes in serum-based indicators of stress. Serum cortisol levels, the predominant corticosteroid in mammals and a commonly used indicator of stress, was measured to evaluate its potential as a chronic stress indicator in bears. The induction time of the cortisol response to stressor exposure is rapid and will be influenced by the stress relating to capture. Hence, serum levels of heat shock proteins (hsps), specifically the 60 (hsp60) and 70 kilodalton (hsp70) families of hsps were also measured to evaluate their reliability as a stress indicator in bears. Traditionally, heat shock proteins have been measured in tissues; however recent studies have indicated their presence in serum in response to chronic stress. In addition, the study examined the feasibility of using corticosteroid-binding globulin (CBG), a serum protein that binds cortisol, as a stress indicator in bears. CBG regulates the availability of cortisol to the tissues (only unbound cortisol elicits a response) but unlike cortisol is not rapidly regulated by acute stress. Bear CBG was isolated and a specific anti-bear CBG antibody was generated. The development of an enzyme-linked immunoadsorbant assay (ELISA) using this bear anti-CBG has the potential to be a useful tool to determine longer-term stress response in bears. Known life-history variables were correlated to the observed levels of serum indicators to elucidate which environmental factors impact bears. The length of sea ice coverage was the strongest determinant of serum cortisol and hsp70 levels in polar bears; the longer ice cover reflects more feeding time and this is reduced through climatic warming. This suggests that fasting associated metabolic changes may be impacting serum cortisol response and hsp70 levels in polar bears. For grizzly bears the proportion of protected homerange had the strongest correlation with stress indicators. This suggests that human impact on the environment, including resource extraction and landscape changes, result in altered levels of serum cortisol and hsp70 levels. Hsp60 was not observed to vary significantly in the face of changing environmental variables, and as such no correlation could be made between serum hsp60 levels and environmental variables in bears. Serum hsp70 was observed to change significantly in response to environmental variables in both polar and grizzly bears. These data along with the changes in cortisol and other health based indicators have the potential to make hsp70 a useful indicator of altered health status in bears. This study is the first attempt to integrate the usefulness of a suite of serum indicators of stress as a tool for detecting the health status of bears. The lack of a control group for comparison to wild population limits the utility of the observed variables as a tool to detect stressed states in bears. However, as these serum indicators are also modulated by the animals health life-history, including food limitation, the monitoring of these serum stress indicators, along with other indicators of fed and fasted states, may give a better picture of the health status of the animal related to nutrient availability.
8

Evaluation of indicators of stress in populations of polar bears (Ursus maritimus) and grizzly bears (Ursus arctos)

Hamilton, Jason 07 January 2008 (has links)
Grizzly and polar bears are both species at the top of the food chain in their respective ecosystems, and as such are indicative of the overall health of the ecosystem. Presently there is little data regarding the stress status of these animals. The development of reliable indicators of stress is important as both species face rapid environmental change. Polar bears from Hudson’s Bay (Ontario, Canada) and grizzly bears from Alberta, Canada, were anaesthetized and blood samples retrieved. Samples were assayed for changes in serum-based indicators of stress. Serum cortisol levels, the predominant corticosteroid in mammals and a commonly used indicator of stress, was measured to evaluate its potential as a chronic stress indicator in bears. The induction time of the cortisol response to stressor exposure is rapid and will be influenced by the stress relating to capture. Hence, serum levels of heat shock proteins (hsps), specifically the 60 (hsp60) and 70 kilodalton (hsp70) families of hsps were also measured to evaluate their reliability as a stress indicator in bears. Traditionally, heat shock proteins have been measured in tissues; however recent studies have indicated their presence in serum in response to chronic stress. In addition, the study examined the feasibility of using corticosteroid-binding globulin (CBG), a serum protein that binds cortisol, as a stress indicator in bears. CBG regulates the availability of cortisol to the tissues (only unbound cortisol elicits a response) but unlike cortisol is not rapidly regulated by acute stress. Bear CBG was isolated and a specific anti-bear CBG antibody was generated. The development of an enzyme-linked immunoadsorbant assay (ELISA) using this bear anti-CBG has the potential to be a useful tool to determine longer-term stress response in bears. Known life-history variables were correlated to the observed levels of serum indicators to elucidate which environmental factors impact bears. The length of sea ice coverage was the strongest determinant of serum cortisol and hsp70 levels in polar bears; the longer ice cover reflects more feeding time and this is reduced through climatic warming. This suggests that fasting associated metabolic changes may be impacting serum cortisol response and hsp70 levels in polar bears. For grizzly bears the proportion of protected homerange had the strongest correlation with stress indicators. This suggests that human impact on the environment, including resource extraction and landscape changes, result in altered levels of serum cortisol and hsp70 levels. Hsp60 was not observed to vary significantly in the face of changing environmental variables, and as such no correlation could be made between serum hsp60 levels and environmental variables in bears. Serum hsp70 was observed to change significantly in response to environmental variables in both polar and grizzly bears. These data along with the changes in cortisol and other health based indicators have the potential to make hsp70 a useful indicator of altered health status in bears. This study is the first attempt to integrate the usefulness of a suite of serum indicators of stress as a tool for detecting the health status of bears. The lack of a control group for comparison to wild population limits the utility of the observed variables as a tool to detect stressed states in bears. However, as these serum indicators are also modulated by the animals health life-history, including food limitation, the monitoring of these serum stress indicators, along with other indicators of fed and fasted states, may give a better picture of the health status of the animal related to nutrient availability.
9

Woodland caribou conservation in the Little Smoky wolf management and the role of bears /

Robichaud, Christine Bernice. January 2009 (has links)
Thesis (M. Sc.)--University of Alberta, 2009. / Title from pdf file main screen (viewed on Dec. 17, 2009). "A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Ecology, Department of Biological Sciences, University of Alberta." Includes bibliographical references.
10

Using multiple regression analysis to associate education levels and financial compensation with livestock producers' tolerance for grizzly bears in the Northern Continental Divide Ecosystem

Vollertsen, John Alvin. January 2005 (has links) (PDF)
Thesis (Ed. D.)--Montana State University--Bozeman, 2005. / Typescript. Chairperson, Graduate Committee: Betsy Palmer. Includes bibliographical references (leaves 111-118).

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