• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 37
  • 24
  • 3
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 89
  • 12
  • 11
  • 11
  • 10
  • 9
  • 9
  • 8
  • 8
  • 8
  • 7
  • 6
  • 6
  • 6
  • 5
  • 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.
81

Évaluation de la toxicité du kétoprofène chez le dragon barbu (Pogona vitticeps)

Vigneault, Annabelle 01 1900 (has links)
La cyclooxygénase (COX) 1 augmente significativement dans la peau inflammée des Ophidiens et dans les muscles inflammés des Chéloniens. Les inhibiteurs non sélectifs de la COX-1 et de la COX-2, comme le kétoprofène, pourraient donc réduire l’inflammation plus efficacement chez les reptiles que les inhibiteurs préférentiels de la COX-2. L’objectif de cette étude était d’évaluer les effets adverses potentiels du kétoprofène chez le dragon barbu (Pogona vitticeps). Treize dragons barbus ont été répartis aléatoirement dans trois groupes lors d’une étude prospective, randomisée, contrôlée et en aveugle. Ils ont reçu une administration intramusculaire quotidienne d’un traitement durant 14 jours. Le groupe 1 (n = 5) a reçu de la saline, le groupe 2 (n = 4) a reçu 2 mg/kg de kétoprofène (dilué 1:10 avec de la saline) et le groupe 3 (n = 4) a reçu 20 mg/kg de kétoprofène (non dilué). Des paramètres biochimiques, des tests de sang occulte fécal et le temps de coagulation sanguine ont été évalués avant et après les deux semaines de traitements. Une évaluation histopathologique des reins, du système digestif, du foie et des muscles a été effectuée. Cliniquement, une réaction aux sites d’injections a été détectée dans le groupe 3. Il n’y avait pas de différences dans les valeurs biochimiques et les temps de coagulation avant et après les traitements, ni entre les groupes. Aucune lésion n’a été détectée à l’évaluation histologique des reins, du foie et du tractus gastro-intestinal. Des lésions histopathologiques de nécrose musculaire aux sites d’injections ont été notées dans tous les groupes et elles étaient statistiquement plus sévères dans le groupe 3 que dans le groupe 1. En conclusion, l’administration intramusculaire quotidienne de 2 mg/kg de kétoprofène dilué durant 14 jours n’a pas causé d’effets adverses chez ce petit nombre de dragons barbus, tandis que de la nécrose musculaire sévère a été détectée suite à l’administration de 20 mg/kg de kétoprofène non dilué. / Cyclooxygenase (COX) 1 has been shown to increase significantly in inflamed ophidian skin and chelonian muscles. Non-selective COX-1 and COX-2 inhibitors, such as ketoprofen, could therefore reduce inflammation more effectively than preferential COX-2 inhibitors in reptiles. The objective of this study was to evaluate potential adverse effects of ketoprofen in bearded dragons (Pogona vitticeps). Thirteen adult bearded dragons were divided into three groups receiving daily intramuscular injections for 14 days in a prospective randomized controlled blinded study design. Group 1 (n = 5) received saline, group 2 (n = 4) received ketoprofen at 2 mg/kg (diluted 1:10 with saline) and group 3 (n = 4) received ketoprofen at 20 mg/kg (undiluted). Biochemical values, fecal occult blood tests and blood clotting time were assessed before and after the two- week treatment. Renal, digestive, hepatic and muscular histopathology was evaluated. Clinically, injection site reactions were noted in group 3 only. No other clinical adverse effects were detected. No changes were detected in plasma biochemical values and clotting times before and after treatments, nor between control and treatment groups. No lesion associated with ketoprofen toxicity was detected on histologic examination of the kidney, liver and gastrointestinal tract. Histopathological lesions of muscular necrosis at the injection sites were noted in all groups and were statistically more severe in group 3 compared to group 1. In conclusion, daily intramuscular administration of diluted ketoprofen at 2 mg/kg for 14 days did not cause adverse effects in a small number of bearded dragons, while severe muscular necrosis was detected following administration of undiluted ketoprofen at 20 mg/kg.
82

The Ecological Effects of Prescribed Fire on the Black Racer (<i>Coluber constrictor</i>)

Howey, Christopher A. F. 10 June 2014 (has links)
No description available.
83

Multilocus sequence typing analyses of Salmonella enterica subspecies enterica

Sangal, Vartul 29 January 2009 (has links)
Serovare von Salmonella enterica subspecies enterica sind im allgemeinen pathogen für Mensch und andere Säugetiere. In dieser Arbeit habe ich anhand eines “Multilocus Sequences Typing” Typisierungsschemas die Populationsstruktur einer der am häufigsten auftretenden Serovaren dieser Subspecies, das aus Menschen und Schlachttieren isolierte Serovar Newport charakterisiert. Dieses Schema wurde auch für die Charakterisierung von Isolaten derselben Subspecies aus humanen Dauerträgern und Reptilien verwandt, um zu bestimmen, ob Isolate aus diesen Quellen sich in ihrer Populationstruktur von denjenigen unterscheiden, die aus anderen Quellen isoliert wurden. Multilocus Sequences Typing ist eine weitgehend für die Untersuchung der Evolution und Populationsstruktur von einen breiten Spektrum von Organismen verwendete Technik. 400 - 600 bp lange Fragmente von 7 Haushaltsgenen wurden sequenziert, und jede einzelne Sequenz jedes einzelnen Gens wurde eine Allelnummer zugeordnet. Jede einzelne Allelkombination wurde einem Sequenztyp zugeordnet. Die so gewonnenen Daten wurden weiter analysiert. Drei “Lineages”, Newport-I, Newport-II und Newport-III, wurden innerhalb dieses Serovars identifiziert, die jeweils aus Menschen in Europa, Tieren und Menschen in Nordamerika isoliert wurden. Der Multiresistenz-Phänotyp wurde häufiger in Newport II gefunden, während die meisten Newport III Isolate pan-sensitiv waren. Verglichen mit anderen Serovaren war die Anzahl von “Lineages” innerhalb Newport höher als bei Enteritidis, Kentucky und Typhimurium, aber niedriger als bei Paratyphi B. Das heisst, die Serovare von S. enterica subspecies enterica variieren stark in ihrer Populationsstruktur. Die Sequenztypen in Isolaten aus humanen Dauerträgern waren im allgemeinen am häufigsten in Isolaten von klinischen Patienten und Tieren vorhanden. In der Mehrheit der Serovaren waren die meisten Isolate aus Patienten und Tieren genetisch identisch mit solchen, die aus gesunden Trägern isoliert wurden. Die genetische Variabilität war zwischen Isolaten aus diesen Quellen vergleichbar. Diese Ergebnissen deuten daraufhin, dass Salmonellen aus Dauerträgern sowie Isolate aus Patienten und Tieren derselben Population angehören. Die meisten Serovare aus Reptilienisolaten waren genetisch identisch mit denen von Menschen und warmblütigen Tieren. In den Serovaren Bovismorbificans, Decatur, Miami und Oranienburg hingegen waren die meisten Isolate aus Reptilien genetisch anders als Isolate aus anderen Wirten. Allerdings wurden nur wenige Isolate der Serovaren Bovismorbificans, Decatur und Miami aus Reptilien und nur wenige Isolate der Serovaren Oranienburg aus anderen Quellen getestet; eine grössere Anzahl von Isolaten müsste daher untersucht werden, um festzustellen ob diese genetischen Unterschiede statistich signifikant sind oder nicht. / Serovars of Salmonella enterica subspecies enterica are generally pathogenic to humans and other mammals. In this study, I examined the population structure of one of the most common serovars of this subspecies isolated from humans and food animals, serovar Newport, using a multilocus sequence typing scheme. This scheme was also used to analyze isolates of this subspecies from chronic human carriers and reptiles to determine whether isolates from these sources represent distinct populations than those from other hosts. Multilocus sequence typing has extensively been used to study evolution and population structure of a wide range of organisms. 400-600 bp fragments of 7 housekeeping genes were sequenced and every unique sequence of each gene fragment was given a distinct allele number. Each unique combination of alleles was assigned a distinct sequence type number. The data were used in further analyses. Three lineages, namely Newport-I, Newport-II and Newport-III were identified within serovar Newport which were associated to European humans, animals and humans in North America, respectively. Multidrug resistance phenotypes were most common in Newport-II whereas most isolates in Newport-III were pan-susceptible. When compared to other serovars, the numbers of lineages within Newport were higher than for Enteritidis, Kentucky and Typhimurium but lower than for Paratyphi B. Therefore, serovars of S. enterica subspecies enterica vary greatly in their population structures. The sequence types observed for isolates from chronic human carriers were generally the most common among human-clinical and animal isolates. Most isolates from non-carrier humans plus animals were genetically identical to the carried isolates within most serovars. Genetic diversity was also comparable between isolates from these sources. These results suggest that salmonellae from chronic human carriers belong to the same population as isolates from non-carrier humans and animals. For most serovars, most isolates from reptiles were genetically identical to those from humans or other warm blooded animals. However, in serovars Bovismorbificans, Decatur, Miami and Oranienburg, most reptile isolates were genetically distinct from isolates from other hosts. Only few reptile isolates were tested from Bovismorbificans, Decatur and Miami and only few non-reptile isolates were tested from Oranienburg, and in larger numbers of such isolates would be needed to determine whether these differences are statistically significant.
84

RESOURCE PARTITIONING BETWEEN TWO SYMPATRIC AUSTRALIAN SKINKS, EGERNIA MULTISCUTATA AND EGERNIA WHITII STEPHEN BELLAMY Thesis submitted in total fulfilment of the requirements of the degree of Doctor of Philosophy AUGUST 2006 SCHOOL OF BIOLOGICAL SCIENCES FLINDERS UNIVERSITY, ADELAIDE, SOUTH AUSTRALIA ________________________________________

Bellamy, Stephen, steve.bellamy@flinders.edu.au January 2007 (has links)
When species compete for resources, in a stable homogeneous environment, there are two possible outcomes. The first is that one species will out-compete the other and exclude it from the environment. This is known as the competitive exclusion principle. The second is that both species will manage to coexist. Coexistence can only occur if the species’ niches are differentiated such that interspecific competition is minimised, or eliminated. This outcome is known as resource partitioning. Two closely related Australian skink species of the Egernia genus, Egernia multiscutata and Egernia whitii, are abundant and sympatric on Wedge Island in South Australia’s Spencer Gulf. The species are morphologically very similar and appear to have very similar life histories and habitat requirements. Ostensibly, they would compete for limiting resources in this environment. This thesis is the first investigation into resource partitioning in this previously unstudied model organism. I report the results of multi-faceted investigations into the coexistence of the skinks, E. multiscutata and E. whitii on Wedge Island and the evidence for, and mechanisms of, any facultative resource partitioning between them. Study methods involved a transect survey of most of Wedge Island to determine the species’ distributions and any evidence for resource partitioning; a morphological comparison to investigate any potential competitive advantages of either species; a habitat choice experiment to establish retreat-site preferences in the absence of interspecific interference; and, a series of staged dyadic encounter experiments to investigate interspecific competitive interactions. Resource partitioning was evidenced by differential distributions of the species among substrates containing the elements required for permanent refuge shelters. This partitioning was not mediated by avoidance of particular substrates but by the presence of the opponent species, combined with attraction to suitable substrates. Asymmetries in some morphological characters were found to confer a potential competitive advantage to E. multiscutata in agonistic encounters with E. whitii. Both species were found to have the same refuge site preferences when interference competition was experimentally removed. This result was not concordant with observed resource partitioning in the field and suggests that the habitat choices of both species are modified by the presence of the opponent species. Analyses of staged dyadic encounter experiments showed that E. multiscutata was more likely to gain greater access to a contested habitat resource and more likely to exclude E. whitii from the resource than vice-versa. Nevertheless, the outcome of competitive interactions was not completely deterministic and there was some tolerance of co-habitation. E. multiscutata’s competitive advantage was attributable largely to its greater mass and head dimensions relative to snout to vent length. However, differential behavioural responses to the threat of larger opponent size also played an important part in resource partitioning between the species.
85

Origins of genetic variation and population structure of foxsnakes across spatial and temporal scales

ROW, JEFFREY 11 January 2011 (has links)
Understanding the events and processes responsible for patterns of within species diversity, provides insight into major evolutionary themes like adaptation, species distributions, and ultimately speciation itself. Here, I combine ecological, genetic and spatial perspectives to evaluate the roles that both historical and contemporary factors have played in shaping the population structure and genetic variation of foxsnakes (Pantherophis gloydi). First, I determine the likely impact of habitat loss on population distribution, through radio-telemetry (32 individuals) at two locations varying in habitat patch size. As predicted, individuals had similar habitat use patterns, but restricted movements to patches of suitable habitat at the more disturbed site. Also, occurrence records spread across a fragmented region were non-randomly distributed and located close to patches of usable habitat, suggesting habitat distribution limits population distribution. Next, I combined habitat suitability modeling with population genetics (589 individuals, 12 microsatellite loci) to infer how foxsnakes disperse through a mosaic of natural and altered landscape features. Boundary regions between genetic clusters were comprised of low suitability habitat (e.g. agricultural fields). Island populations were grouped into a single genetic cluster suggesting open water presents less of a barrier than non-suitable terrestrial habitat. Isolation by distance models had a stronger correlation with genetic data when including resistance values derived from habitat suitability maps, suggesting habitat degradation limits dispersal for foxsnakes. At larger temporal and spatial scales I quantified patterns of genetic diversity and population structure using mitochondrial (101 cytochrome b sequences) and microsatellite (816 individuals, 12 loci) DNA and used Approximate Bayesian computation to test competing models of demographic history. Supporting my predictions, I found models with populations which have undergone population size drops and splitting events continually had more support than models with small founding populations expanding to stable populations. Based on timing, the most likely cause was the cooling of temperatures and infilling of deciduous forest since the Hypisthermal. On a smaller scale, evidence suggested anthropogenic habitat loss has caused further decline and fragmentation. Mitochondrial DNA structure did not correspond to fragmented populations and the majority of foxsnakes had an identical haplotype, suggesting a past bottleneck or selective sweep. / Thesis (Ph.D, Biology) -- Queen's University, 2011-01-11 10:40:52.476
86

Ecological and Physiological Effects of Proximity to Roads in Eastern Box Turtles (<i>Terrapene carolina carolina</i>)

Weigand, Nicole Marcel 01 October 2018 (has links)
No description available.
87

The illegal reptile trade - a criminological perspective

Herbig, Friedo Johann Willem 30 June 2003 (has links)
The illegal reptile trade quandary in the Western Cape province is strategically and chronologically addressed in this thesis with the implicit intention of revealing its gamut and underlying dynamics, developing a pragmatic, parsimonious and authentic conservation crime category with clearly delineated parameters, and formulating an integrated theoretical explanation regarding its aetiology that will adequately explicate herpetological, and hopefully also other forms of natural resource, crime and deviance. The thesis, by essentially transcending traditional, stereotypical edicts, throws new light on a severely neglected and underestimated form of natural resource exploitation, highlighting the need for reptiles, as the sentinels of the state of our environmental health to be preserved and perpetuated for, in the final analysis, the benefit of human kind. Through an essentially explorative enquiry, utilising an integrated qualitative -quantitative research approach, the concept of conservation crime, as a vanguard to an innovative and unified conservation criminology, is introduced in this thesis in the form of unambiguous adjunct of the mainstream criminological discipline. It is, furthermore, utilised as a conduit within the herpetological crime framework to enrich the criminological discipline as a whole, broaden its frontiers, promote effective and focussed intervention/mitigation initiatives, as well as stimulate interest for further investigation in this field. Fragmented, antiquated and nebulous legislation, deficient conservation and related role-player organisational capacity and inconsistent penalties, in concert with apathetic (and decidedly generic) societal attitudes and traditional pessimistic rubric regarding reptiles, emerge as fundamental proclivities impeding the effective intercession and management of the natural resources embodied in this sphere. Injudicious manipulation of the Western Cape's scarce and specialised reptile resources and the biodiversity ramifications such exploitation realises portend the intensification and diversification potential of such criminality. Conservation criminology, as developed and presented in this thesis, underscores the significant contribution this field of criminology can make in comprehending the illegal manipulation/exploitation of herpetological and other natural resources, expanding and enhancing its theoretical constructs and implementing justice through decisive, dedicated and holistic intervention programmes/strategies in order to defend the inherent right to the continued existence of all reptile species. / Crimonology / D. Litt et Phil. (Criminology)
88

The illegal reptile trade - a criminological perspective

Herbig, Friedo Johann Willem 30 June 2003 (has links)
The illegal reptile trade quandary in the Western Cape province is strategically and chronologically addressed in this thesis with the implicit intention of revealing its gamut and underlying dynamics, developing a pragmatic, parsimonious and authentic conservation crime category with clearly delineated parameters, and formulating an integrated theoretical explanation regarding its aetiology that will adequately explicate herpetological, and hopefully also other forms of natural resource, crime and deviance. The thesis, by essentially transcending traditional, stereotypical edicts, throws new light on a severely neglected and underestimated form of natural resource exploitation, highlighting the need for reptiles, as the sentinels of the state of our environmental health to be preserved and perpetuated for, in the final analysis, the benefit of human kind. Through an essentially explorative enquiry, utilising an integrated qualitative -quantitative research approach, the concept of conservation crime, as a vanguard to an innovative and unified conservation criminology, is introduced in this thesis in the form of unambiguous adjunct of the mainstream criminological discipline. It is, furthermore, utilised as a conduit within the herpetological crime framework to enrich the criminological discipline as a whole, broaden its frontiers, promote effective and focussed intervention/mitigation initiatives, as well as stimulate interest for further investigation in this field. Fragmented, antiquated and nebulous legislation, deficient conservation and related role-player organisational capacity and inconsistent penalties, in concert with apathetic (and decidedly generic) societal attitudes and traditional pessimistic rubric regarding reptiles, emerge as fundamental proclivities impeding the effective intercession and management of the natural resources embodied in this sphere. Injudicious manipulation of the Western Cape's scarce and specialised reptile resources and the biodiversity ramifications such exploitation realises portend the intensification and diversification potential of such criminality. Conservation criminology, as developed and presented in this thesis, underscores the significant contribution this field of criminology can make in comprehending the illegal manipulation/exploitation of herpetological and other natural resources, expanding and enhancing its theoretical constructs and implementing justice through decisive, dedicated and holistic intervention programmes/strategies in order to defend the inherent right to the continued existence of all reptile species. / Crimonology / D. Litt et Phil. (Criminology)
89

Plant and Herpetofaunal Responses to Wetland Restoration on Pinckney Island National Wildlife Refuge, Beaufort County, South Carolina

Clark, Sabrina Diane 05 May 2007 (has links)
Habitat destruction and modification are major causes cited for the decline of amphibians worldwide (Wake and Morowitz 1991). Depressional wetlands on Pinckney Island NWR in Beaufort County, South Carolina were ditched and drained during the 1950?s for agricultural development. Wetlands were restored by filling ditches with existing spoil. I surveyed herpetofaunal and vegetation communities to determine responses to wetland restoration on Pinckney Island from 2004-2005. I selected ten wetlands each in pine and maritime habitats, sampling prior to and after restoration. I recorded 14 reptile and 9 amphibian species using time-constrained searches and funnel trap arrays. I documented (first record on the Island) Fowler?s toad (Bufo woodhousei) and many-lined salamander (Stereochilus marginatus). There were differences between amphibian species richness recorded using time constrained surveys and funnel trap arrays, amphibian species abundance between pine and maritime forest, and between number of Eastern spadefoot toads (Scaphiopus holbrooki) before and after restoration.

Page generated in 0.0507 seconds