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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.
281

Ticks and Tick-Borne Pathogens Associated with Feral Swine in Edwards Plateau and Gulf Prairies and Marshes Ecoregions of Texas

Sanders, David M. 2011 May 1900 (has links)
Feral swine (Sus scrofa domesticus) are spreading across North America at an alarming rate. Four Canadian provinces and 39 states within the continental United States now report standing populations of feral pigs. Estimates place the number of feral hogs in Texas >2M, accounting for more than half of the United States population. It is known that feral swine impact local ecology following establishment, with regard to shifts in local flora and fauna. The overall objective of this research was to investigate the role of feral swine in tick-borne pathogen transmission in Texas. The underpinning objectives were to establish host records for tick species parasitizing feral swine, determine the species assemblages associated with feral swine among different ecoregions of Texas, determine by immunoassay to which tick-borne bacteria feral pigs were being exposed, and detect the DNA of tick-borne bacteria by polymerase chain reaction assay in the event of poor or early immune response by the host. Feral pigs (N=432) were harvested from June 2008 to June 2010 using box and corral traps and by aerial gunning. Seven species of ticks, Amblyomma americanum, A. cajennense, A. maculatum, Dermacentor albipictus, D. halli, and D. variabilis; and Ixodes scapularis, were collected. Immature stages of A. cajennense and A. americanum were collected as well. All classes of feral pigs, gender by age, were infested with ticks. Serum was collected through a multi-organizational effort from 2006 to 2010 and tested by ELISA for previous exposure to tick-borne pathogens in the genera Rickettsia and Ehrlichia (N=888) and Borrelia (N=849). Prevalence percentages by immunoassay were 27.59 percent, 13.18 percent and 2.12 percent for Rickettsia, Ehrlichia, and Borrelia, respectively. Samples positive by ELISA for exposure to Borrelia were further screened by Western Blot for exposure to Borrelia turicatae. The results were equivocal in most cases. Blood samples (N=233) were collected from 2008 to 2010 and analyzed by polymerase chain reaction for the detection of the DNA of these same three genera of bacteria. Two of the samples were positive by PCR for the presence of Borrelia DNA. Texas feral swine are serving as hosts for at least seven species of ticks and are interacting with tick-borne pathogen transmissions cycles in Texas.
282

Towards reusable aspects: the callback mismatch problem

Bynens, Maarten, Van Landuyt, Dimitri, Truyen, Eddy, Joosen, Wouter January 2010 (has links)
Because software development is increasingly expensive and timeconsuming, software reuse gains importance. Aspect-oriented software development modularizes crosscutting concerns which enables their systematic reuse. Literature provides a number of AOP patterns and best practices for developing reusable aspects based on compelling examples for concerns like tracing, transactions and persistence. However, such best practices are lacking for systematically reusing invasive aspects. In this paper, we present the ‘callback mismatch problem’. This problem arises in the context of abstraction mismatch, in which the aspect is required to issue a callback to the base application. As a consequence, the composition of invasive aspects is cumbersome to implement, difficult to maintain and impossible to reuse. We motivate this problem in a real-world example, show that it persists in the current state-of-the-art, and outline the need for advanced aspectual composition mechanisms to deal with this.
283

Determining patterns and impacts of multiple forest stressors in Southern Ontario /

Tanentzap, Andrew Joseph. January 2007 (has links)
Thesis (M.Sc.)--York University, 2007. Graduate Programme in Biology. / Typescript. Includes bibliographical references (leaves 114-162). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR32029
284

La prise en charge de l'hyperparathyroïdisme primaire par abord mini-invasif est-elle justifiée

Leonard, David Brisler, Patrick January 2004 (has links) (PDF)
Reproduction de : Thèse d'exercice : Médecine : Nancy 1 : 2004. / Titre provenant de l'écran-titre.
285

Ventilation non invasive par aide inspiratoire à domicile le réglage de la fréquence respiratoire influence-t-il le mode ventilatoire des patients /

Jannière-Nartey, Caroline Chollet, Sylvaine. January 2007 (has links)
Thèse d'exercice : Médecine. Pneumologie : Nantes : 2007. / Bibliogr.
286

Analysis of intraspecific and interspecific interactions between the invasive exotic tree-of-heaven (Ailanthus altissima (Miller) Swingle) and the native black locust (Robinia pseudoacacia L.)

Call, Lara J. January 2002 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 2002. / Title from PDF t.p. (viewed on Dec. 10, 2005). Vita. Includes bibliographical references (p. 70-78).
287

Brassica tournefortii phenology, interactions and management of an invasive mustard /

Marushia, Robin Gene. January 2009 (has links)
Thesis (Ph. D.)--University of California, Riverside, 2009. / Includes abstract. Title from first page of PDF file (viewed Febrary 1, 2010). Includes bibliographical references (p. 140-143). Issued in print and online. Available via ProQuest Digital Dissertations.
288

Effects of the spatial heterogeneity formed by Ambrosia dumosa on individual and population growth of the invasive annual grass Schismus barbatus

Rodriguez-Buriticá, Susana, January 2009 (has links)
Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes bibliographical references (p. 119-137).
289

Physiological and Behavioral Mechanisms of Range Expansion in the House Sparrow (Passer domesticus)

Liebl, Andrea Lyn 01 January 2013 (has links)
Introduced species cause both considerable ecological and economic damage every year. However, not much is known about how certain species are able to establish and spread beyond the site of initial introduction, whereas others do not. Species undergoing range expansion following an introduction may prove to be a valuable resource to invasion biology, but may also be informative in light of species' responses to changing environments (i.e. global climate change). Here, I took advantage of an ongoing range expansion of an introduced vertebrate species. House sparrows (Passer domesticus) were introduced to Mombasa, Kenya in the 1950s and have subsequently expanded their range northwest-ward and now occupy most major cities in Kenya. By comparing older, established populations (i.e. those in Mombasa) with more recently colonized populations at the range edge, it might be possible to determine some of the mechanisms that underlie range expansion in some species and/or populations. In Chapter 1, the background and ideas that motivated the rest of the dissertation is summarized. In Chapter 2, I studied how exploration and glucocorticoids (a hormone released in response to stressors) changed throughout the range expansion. Exploration was greater at the range edge, which is likely to ensure greater discovery of novel resources. Glucocorticoids released in response to restraint were also highest at the range edge, which might facilitate resolution of stressors in unpredictable environments. However, chronically elevated levels of glucocorticoids are often considered maladaptive, unless an individual can appropriately cope with them. Therefore, in Chapter 3, I characterized glucocorticoid receptors (i.e. mineralocorticoid receptor (MR) and glucocorticoid receptor (GR)) in the hippocampus, an area responsible for negative feedback of glucocorticoids as well as induction of behavioral and physiological response to stressors. I found that MR density was lower relative to GR density at the range edge compared to the site of introduction (Mombasa). I speculate this pattern is a mechanism to resolve the elevated levels of glucocorticoids at the range edge. Taken together, these results indicate that individuals at the range edge have a strong glucocorticoid response to stressors to induce a rapid, strong response to resolve stressors. Subsequently, in Chapter 4, I examined the potential mechanisms of phenotypic change among Kenyan house sparrows. Typically, following an introduction event, genetic diversity undergoes a bottleneck and is greatly reduced compared to the source population; as such, genetic evolution as the main driver of changing phenotypes throughout the range expansion is unlikely. We therefore hypothesized that epigenetic mechanisms (e.g. DNA methylation) may compensate for the expected reduced genetic diversity following an introduction. Although there was no pattern of epigenetic variation among cities (i.e. variation did not increase nor decrease further from the site of introduction), epigenetic variation increased as genetic inbreeding increased (a sign of reduced genetic diversity and bottlenecks), suggesting epigenetic modifications may compensate for reduced genetic diversity following an introduction event. Overall, patterns of phenotypic variation emerged dependent on age of the population- these patterns may prove to be important in other vertebrate range expansions as well. Surprisingly, epigenetic diversity did not correlate with phenotypic variation among populations; however, within-individual studies may reveal epigenotypes are related to certain behavioral or physiological phenotypes. In the future, studies should be designed to address how phenotypic differences arise despite relatively low genetic diversity and overall high genetic admixture among individuals. In Kenyan house sparrows, maintenance of high levels of flexibility and differential developmental influences may be important factors that lead to varying phenotypes dependent on time since colonization.
290

Magneto-photo-acoustic imaging

Qu, Min 25 June 2012 (has links)
Cancer is a major public health problem worldwide due to its poor prognosis. Detection of cancer in the earliest stages is crucial for the success of therapeutic strategies to truly cure the disease. Molecular imaging provides the potential to diagnose and image cancers at an asymptomatic stage. In molecular imaging, the nanoparticles are designed to target the cancer cells. Molecular imaging is capable of assessing the molecular processes within the tumors by detecting the accumulated or targeted nanoparticles. However, for most molecular imaging systems, the background signal is a common problem, obscuring signals from specific probes and limiting sensitive detection. A hybrid imaging technique, entitled magneto-photo-acoustic (MPA) imaging, was developed as a non-invasive imaging tool to detect nanoparticles, which are used to target pathologies, with high sensitivity and specificity. Based on dual-contrast of both optical absorption and magnetic susceptibility, MPA imaging can significantly improve the molecular contrast specificity as well as investigate the interaction of nanoparticles with cells. Studies were performed using tissue-mimicking phantoms, ex vivo tissue sample and in vivo animal models of cancer. The results indicate that, coupled with dual-contrast agent, the molecular MPA imaging will allow not only mapping the pathologies located in the body, but also sensing the molecular and physiological processes. / text

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