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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.
431

Activation of cells of the mast cell/basophil lineage in response to potential allergens in the absence of IgE sensitisation

Smyth, Lucy J. C. January 1999 (has links)
No description available.
432

Copulation and the evolution of genital morphology in the damselfly Calopteryx haemorrhoidalis asturica

Cordoba-Aguilar, Alejandro January 1999 (has links)
No description available.
433

Nonlinear systems identification using the Narmax method

Mao, Ke Zhi January 1998 (has links)
No description available.
434

Multicomponent signals

Rowe, Candida L. January 1998 (has links)
No description available.
435

Interorganizational Partner Selection as Negotiation: A Study of Two Distance Education Consortia

Pidduck, Anne Banks January 2005 (has links)
The choice of appropriate collaborative partners has consistently been reported as a key issue for contemporary managers. This study reports findings from a study which explored the process and criteria of partner selection - how and why partners are chosen. The results show multiple cycles of deal-making, partnership roles and organizational approval. Partner choice criteria focused on partnership requirements, but was influenced by additional factors. These results suggest that partner selection may be much more complex than previously recognized and could be better described as partner negotiation. <br /><br /> The researcher reviewed recent literature on partnerships, decision-making, and partner selection. Concepts from this previous work were updated with data from three initial interviewees experienced in university-industry partnerships. A conceptual Partner Negotiation Model was developed including three cycles of Deal-Making, Organizational Approval, and Partner Role/Selection. Our hypothesized Partner Choice Criteria centred on requirements, but were influenced by resource availability, social network, reputation, politics, and ambiguity. Two Canada-wide distance education consortia were identified as large-scale case studies for investigation of the research theory. A total of 34 informants were contacted. Written business plans, contracts, documents, partner network diagrams and 231 archival e-mails from 36 correspondents were collected and analysed for the two consortia. <br /><br /> The results showed strong support for partner selection included in negotiation cycles of deal-making and organizational approval. Partner choice criteria supported the need to meet documented requirements, but was also strongly influenced by resource availability, social network, and reputation. Additional issues of interest to the interviewees were motivation, operations, unit of partner, self-sustaining income, and integration to one consortium. As well, the Case Study Narratives offered deep, interesting insight into two specific cases of Canadian consortia. <br /><br /> The findings suggest that the formation of partnerships and the process of partner selection are both very complex. This research has provided new insights linking business negotiation concepts with partner selection. A model has been developed for viewing partner selection as negotiation. Three negotiation cycles of deal-making, organizational approval, and partner role/selection have been proposed. The research has identified four criteria that influence why specific partners are chosen ? requirements, resource availability, social network, and reputation. Finally, based on the complexities and issues from this work, a number of ideas for future research have been summarized.
436

The psychology of information selection and reasoning

Morris, M. Frances G. January 1997 (has links)
No description available.
437

Facial attractiveness among rhesus macaques (Macaca mulatta) : manipulating and measuring preferences for conspecifics' facial characteristics

Waitt, Corri January 2005 (has links)
The face holds a central role in both human and nonhuman primate social interactions, through the communication of feelings and intentions via facial expressions and by acting as a means of recognising individuals. Humans, however, also employ their faces in mate attraction and assessment, an area that has received little attention in nonhuman primates. Many researchers have proposed that human aesthetic judgments of facial attractiveness have a biological basis, and these preferences have evolved via sexual selection processes during human evolution. The use of the face in attractiveness assessments need not be limited to humans. Rather, there is good reason to suggest that this may also apply to other nonhuman primates, based on homologies in the way in which primates use their faces, and on evidence that the face is a site of sexual selection for many primate species. It was the aim of this thesis to explore whether facial traits may also play a role in judgements of attractiveness in a nonhuman primate, the rhesus macaque( Macaca mulatta), in an effort to understand whether humans are unique in utilising the face as a mechanism of mate assessment. Three factors that are reported to influence facial attractiveness in humans are facial symmetry, sexual dimorphism, and averageness. To assess whether they also play a role in nonhuman primates, a series of experiments were conducted where digital images of adult male and female rhesus macaque faces were altered for these features. Opposite-sexed images were then displayed to adult males and females in a captive setting. Eye gaze measures were utilised to assess visual preference for, and the relative importance of, these traits. These experiments yielded mixed results. Increasing facial symmetry of opposite-sexed conspecifics positively influenced the dependent gaze measures employed here. Manipulating degree of facial sexual dimorphism had little influence on the visual gaze of either sex. Facial averageness positively influenced visual preferences for opposite-sexed conspecifics among both sexes, although increasing degree of averageness did not. The last topic to be explored was facial colouration. Rhesus macaques like, various other species of anthropoid primates, possess facial displays of red secondary sexual colouration. As above, animals viewed digitally altered pale and red versions of opposite-sexed conspecifics. Although females displayed preferences for red male faces, males displayed no clear preferences based on female facial colour. This raises the possibility that male and female facial colour may serve different roles in intraspecific signaling. While it cannot be concluded that visual preferences are indeed indicative of real-life preferences, the results do indicate that animals are not indifferent to variations in conspecific facial features. The present findings have important implications regarding the evolution of facial attractiveness, as they provide the first experimental evidence suggesting that facial features may serve as a mechanism for mate selection across primate taxa and that both human and nonhuman primates may employ similar criteria to appraise facial attractiveness.
438

A qualitative analysis of selection to flag rank in the United States Navy

Schwind, David A. 06 1900 (has links)
Approved for public release, distribution is unlimited / This thesis is a qualitative analysis of selection to Rear Admiral (Lower Half) in the United States Navy. Specifically, this thesis examines the variables in the career of senior US Navy officers that can be considered as factors in determining advancement at the O-7 selection board. The researcher conducted 18 semi-structured interviews with active duty and retired flag officers, using a protocol based on an analysis of archival data from flag officers promoted from year groups 1972 to 1978, and relevant literature to determine what factors are considered during the selection board process. Overall, the data indicate that select background and performance variables are important factors in the promotion of flag officers. Examples include the importance of reputation and fitness report rankings and the lack of weight given to factors such as commissioning source and letters of recommendation. / Lieutenant, United States Navy
439

Approche moléculaire de l’adaptation différentielle d'un poisson laguno-marin (Dicentrarchus labrax L.) en populations naturelles et d'élevage / Molecular approach to diferential adaptation of a lagoon-marine fish (Dicentrarchus labrax) in natural population and hatchery

Quéré, Nolwenn 21 May 2010 (has links)
L'identification de marqueurs génétiques liés à des gènes permet une exploration des éventuelles corrélations existant entre leur variabilité génétique et des pressions sélectives portant sur les gènes, aussi bien dans un contexte de populations expérimentales que naturelles. Chez le loup de mer (Dicentrarchus labrax), douze locus associés à des gènes - dont quatre associés aux gènes de l'hormone de croissance (GH), la somatolactine (SL) ou l'IGF-1- et huit locus anonymes ont servi à mener une étude multi-échelle de la différenciation génétique. La structure en trois bassins connue chez cette espèce a été confirmée mais les locus liés aux gènes ont montré une différenciation significativement plus forte que les locus anonymes et impliquant des barrières aux flux géniques nucléaires supérieures à celles admises jusqu'alors. A l'échelle mer-lagune, aucune image cohérente de différenciation génétique n'a pu être obtenue. Parallèlement, une expérience d'acclimatation à l'eau douce a été réalisée. Si les individus soumis à la désalure ont subi une mortalité importante, aucune différence génétique significative n'est observée entre les individus ayant survécu au traitement et ceux restés en eau de mer, excepté pour un locus EIF3E. Ces résultats ont révélé une composante familiale liée à l'expérimentation, mais les déterminismes génétiques sous-jacents restent obscurs. L'utilisation de marqueurs liés à des gènes a permis de révéler l'implication au moins indirecte de certains de ces gènes dans la mise en place d'une structuration génétique de l'espèce, mais également dans la réponse physiologique des individus à un stress environnemental pouvant être rencontré en conditions naturelles. / The identification of gene-linked genetic markers allows the exploration of potential correlations between their genetic variability and selective pressures acting on the genes in both natural and experimental populations. In Sea Bass (Dicentrarchus labrax), twelve gene-associated loci – four of them linked to Growth Hormone gene (GH), Somatolactin (SL) or IGF-1- and height anonymous loci were used in a multi-scale study of the genetic differentiation. The structure in three basins know in this species is well confirmed with gene-linked markers bearing a significantly higher differentiation than anonymous loci implying some stronger barriers to nuclear gene flow than admitted so far. At the open sea-lagoon scale, no coherent picture can be drawn from the different tests performed. A fresh water acclimation experiment was carried out in parallel. If numerous fishes in low-salt conditions died, the survivors are not genetically different from that maintained in salted water except for one locus EIF3E. These results can be partially explained by a family component but the genetic determinism is not elucidated yet. The use of gene-linked markers succeeded in revealing the involvement, at least indirect, of some of the genes in the edification of a genetic structure inside the species but also in the physiological response of the fishes to an environmental stress that can be encountered in natural conditions.
440

The role of fire, microclimate, and vegetation in lesser prairie-chicken habitat selection

Lautenbach, Jonathan David January 1900 (has links)
Master of Science / Division of Biology / David A. Haukos / The lesser prairie-chicken is a prairie grouse native to the southwestern Great Plains that has experienced significant population and habitat declines since European settlement. Ongoing declines prompted the U.S. Fish and Wildlife Service to list lesser prairie-chickens as threatened under the Endangered Species Act in spring of 2014. In fall of 2015, the listing was vacated on procedural grounds and the lesser prairie-chicken was removed from listing in summer 2016. Despite the legislative change, considerable conservation efforts emerged with the initial listing and have continued following the removal of the species from the threatened and endangered species list. Understanding how lesser prairie-chickens use landscapes and how management actions can influence their space use is important for long-term strategies to meet conservation goals. I modeled lesser prairie-chicken habitat selection relative to landscape mosaics of vegetation patches generated through patch-burn grazing, microclimate, and vegetation characteristics across their range. I captured, attached GPS satellite or VHF radio transmitters to, tracked, and measured vegetation characteristics used by and available to female lesser prairie-chickens across the northern portion of their range in Kansas and Colorado. Female lesser prairie-chickens use all patch types created in a patch-burn grazing mosaic, with female selecting greater time-since-fire patches (>2-years post-fire) for nesting, 2-year post-fire patches during the spring lekking season, 1- and 2-year post-fire patches during the summer brooding period, and 1-year post-fire units during the nonbreeding season. Available vegetation structure and composition in selected patches during each life-cycle stage was similar to the needs of female lesser prairie-chickens during that life-cycle stage. To assess their selected microclimate conditions, I deployed Maxim Integrated Semiconductor data loggers (iButtons) at female flush locations and across a landscape inhabited by lesser prairie-chickens. Females selected locations that minimized thermal stress at microsite, patch, and landscape scales during peak midday temperatures during summer. Females selected midday locations based on vegetation characteristics; where selected sites had >60% forb cover and <25% grass cover, or >75% grass cover and <10% forb cover. In addition, females selected sites with greater visual obstruction. I measured vegetation composition and structure at use and available sites at four study areas located along the precipitation gradient characterizing the full extent of the lesser prairie-chicken range. Vegetation structure use by females varied in relation to long-term precipitation patterns. Females used sites with lower visual obstruction than available during the fall and spring. However, they used vegetation composition that was similar to available within each study area. Overall, my findings indicate that lesser prairie-chickens require structural and compositional heterogeneity to support a suite of habitat needs throughout the year. Therefore, management should focus on providing structural and compositional heterogeneity across landscapes. Greater heterogeneity in vegetation conditions can be achieved through management practices that allow domestic grazers to select grazing locations, such as patch-burn grazing or increased pasture area.

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