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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.
61

Acoustic sampling considerations for bats in the post-white-nose syndrome landscape

Barr, Elaine Lewis 27 January 2020 (has links)
Bat populations across North America are either facing new threats from white-nose syndrome (WNS) and wind energy development or have already experienced precipitous declines. Accordingly, researchers and managers need to know how to best monitor bats to document population and distribution changes, as well as where to look for persisting populations. Landscape-scale WNS impacts to summer bat populations are not well understood, and although acoustic monitoring is commonly used to monitor these populations, there is limited information about differences among acoustic detectors and the implications to managers thereof. My objectives were to model the relationship between WNS impact, influence of available hibernacula, and environmental factors for summer nightly presence of three WNS-affected bats and to compare how multiple models of acoustic detectors perform in terms of detection probability and nightly recorded bat activity. I collected acoustic data from 10 study areas across Virginia, West Virginia, Ohio and Kentucky to describe changes in nightly presence of WNS-affected bat species during summer 2017. During the same period of time, I compared five types of acoustic detectors at Fort Knox, Kentucky. My results show the potential efficacy of using a WNS impact-year metric to predict summer bat presence, and highlight which environmental variables are relevant for large-scale acoustic monitoring. Additionally, my findings suggest that each of the detector types tested would suffice for most research and monitoring activities, but standardization of detector type within the scope of a project or study should be encouraged. / Master of Science / Bat populations across North America are either facing new threats from white-nose syndrome (WNS) and wind energy development or have already experienced devastating declines. Accordingly, wildlife biologists need to know how to best monitor bats to document population and distribution changes, as well as where to look for remaining populations. Landscape-scale WNS impacts to summer bat populations are not well understood, and although acoustic technology is commonly used to monitor these populations, there is limited information about differences among acoustic detectors and the implications to managers thereof. My objectives were to model the relationship between WNS impact, influence of available bat hibernation caves, and environmental factors for summer nightly presence of three WNS-affected bats and to compare how multiple models of acoustic detectors perform in terms of detection probability and nightly recorded bat activity. I collected acoustic data from 10 study areas across Virginia, West Virginia, Ohio and Kentucky to describe changes in nightly presence of WNS-affected bat species during summer 2017. During the same period of time, I compared five types of acoustic detectors at Fort Knox, Kentucky. My results show potential viability of a WNS impact-year metric to predict summer bat presence, and highlight which environmental variables are relevant for large-scale acoustic monitoring. Additionally, my findings suggest that each of the detector types tested would suit most research and monitoring activities, but standardization of detector type within the scope of a project or study should be encouraged.
62

Filogenia de vírus da raiva isolados de morcegos frugívoros do gênero Artibeus e  relacionados a morcegos hematófagos com base nos genes codificadores da nucleoproteína N e glicoproteína G / Phylogeny of rabies virus strains from Artibeus spp. and Desmodus rotundus bats based on the nucleoprotein and glycoprotein genes

Fahl, Willian de Oliveira 26 November 2009 (has links)
Morcegos vêm recebendo crescente importância em Saúde Pública, pois são os principais reservatórios para a raiva em diversas partes do mundo. Estudos filogenéticos baseados no gene N demonstraram que os vírus da raiva (RABV) encontrados em morcegos frugívoros Artibeus spp. são próximos àqueles associados ao morcego hematófago Desmodus rotundus, mas pouco se conhece sobre a diversidade genética do RABV nestes morcegos. Este estudo teve como objetivos avaliar a filogenia de linhagens do RABV variante três (AgV3) relacionadas a morcegos Artibeus spp. e D. rotundus, com base em sequências do gene N e do gene G, e a possibilidade de distinção entre isolados de vírus da raiva detectadas em Artibeus spp. e D. rotundus para a epidemiologia molecular da raiva. Vinte amostras do RABV isoladas de Artibeus spp. e 15 obtidas de bovinos e relacionadas ao D. rotundus, todos do Estado de São Paulo, Brasil, foram submetidas a RT -PCRs, e os amplicons gerados submetidos ao sequenciamento de DNA, e as sequências alinhadas com sequências homólogas obtidas do GenBank para a construção de árvores Neighbor-Joining de nucleotídeos (modelo MCL) e aminoácidos (modelo Poisson), utilizando European bat lyssavirus 1 (EBLV1) como outgroup. A árvore filogenética gerada para o gene N demonstrou a formação de três grupos apoiados em bootstraps de no mínimo 60%. Estes grupos foram denominados como grupo D, exclusivamente com isolados relacionadas ao D. rotundus e A1 e A2 principalmente com isolados de Artibeus spp., enquanto que para o gene G, segregaram em duas linhagens, ou seja, relacionadas ao D. rotundus (grupo D) e relacionadas ao Artibeus spp. (grupo A). Para todos os grupos as identidades de aminoácidos foram superiores às de nucleotídeos, uma indicação da predominância de substituições sinônimas. Concluindo, padrões gênero-específicos para isolados do RABV AgV3 foram detectados em D. rotundus e Artibeus spp., com uma topologia concordante para linhagens fixas em cada um destes quirópteros. Estes resultados mostram uma intrincada relação com o hospedeiro na história evolutiva do RABV, sob o ponto de vista básico, como também a determinação das fontes de infecções na epidemiologia molecular da raiva. / Bats have been assigned an increasing importance in Public Health as these are the main rabies reservoirs in many parts of the world. Phylogenetic studies based on the N gene have shown that rabies virus (RABV) strains from Artibeus spp. frugivorous bats are closely associated to those from the vampire bat Desmodus rotudus, but little is known about the genetic diversity of RABV in these bats. This study aimed to assess the phylogeny of RABV strains from the antigenic variant 3 (AgV3) from these bats based on N and G sequences and to evaluate the possibility of distinction between RABV lineages of these for the molecular epidemiology of rabies. Twenty RABV strains isolated from Artibeus spp. bats and 15 obtained from cattle and related to D. rotundus, all from Sao Paulo State, Brazil, were submitted to RT-PCRs to the N and G genes amplifications and the amplicons were submitted to cycle sequencing; the sequences were aligned with homologous sequences retrieved from the Genbank for the construction of Neighbor-Joining trees for nucleotides (MCL model) and amino acids (Poisson model) with European bat lyssavirus 1 (EBLV1) as outgroup. N gene tree showed three major clusters with bootstraps 60% and named as clusters D, exclusively with strains related to D. rotundus and A1 and A2, chiefly with Artibeus spp. strains while for the G gene only two lineages, i.e., D. rotundus related (cluster D) and Artibeus-related (cluster A) were formed. For all the groups the amino acids identities were superior to the nucleotides identities, an indication of the predominance of synonymous substitutions. As a conclusion, genus specific lineages of AgV3 RABV have been detected in D. rotundus and Artibeus spp. bats with a concordant topology for fixed strains for each of these two bat genus. These results not only show an intricate host-relationship of RABV evolutionary history on the basic point of view, but have an invaluable application for the determination of sources of infections in rabies molecular epidemiology.
63

Ocorrência e caracterização molecular de coronavírus e rotavírus do grupo A em quirópteros do Estado de São Paulo / Ocurrence and molecular characterization of coronavirus and group A rotavirus in chiropterans of São Paulo State

Asano, Karen Miyuki 12 February 2015 (has links)
Diversas doenças virais emergentes e re-emergentes têm sido descritas em morcegos. As alterações ambientais provocadas por seres humanos associada a adaptação dos morcegos às áreas urbanas aumentam as chances da transmissão dessas doenças para humanos e animais domésticos. O estudo das coronaviroses associadas a esse hospedeiro tem evidenciado que os morcegos atuam como reservatório dessa doença, enquanto o estudo das rotaviroses ainda foi pouco explorado. Este estudo tem como objetivo verificar a ocorrência de coronavírus e rotavírus em diversas espécies de morcegos do Estado de São Paulo, Brasil, e realizar inferências filogenéticas a partir dos genes RdRp e S dos coronavírus, assim como de genes de proteínas estruturais e não estruturais dos rotavírus. Para tanto, foi utilizada a RT-PCR seguida de sequenciamento de DNA. Para análise filogenética e de diversidade molecular foi utilizado critério de otimização de distância e cálculo das identidades de nucleotídeos e aminoácidos entre as sequências obtidas e sequências recuperadas do GenBank. A ocorrência de coronavírus foi de 2,95% (9/305) e a de rotavírus de 9,18% (28/305). De acordo com a análise filogenética do gene da RdRp oito amostras foram classificadas como alphacoronavirus. A análise do gene S dos CoV mostrou que as amostras deste estudo formaram uma linhagem única, segregadas das demais amostras de alphacoronavírus. Em relação aos rotavírus, foi possível a identificação de um genótipo G3-P[3]-IX-RX-CX-MX-AX-NX-T3-E3-H6, similar a encontrada em morcegos, equinos e humanos. Além disso, outra amostra foi classificada como G20, similar ao genótipo encontrado em humano, sendo que os genótipos encontrados para os genes VP4, NSP3 e NSP5 desse vírus podem ser classificados como novos genótipos. Os resultados obtidos mostram que esses animais podem carrear agentes infecciosos de importância na saúde pública, sendo que mais estudos são necessários para o esclarecimento do papel dos morcegos como reservatório e fonte de infecção destas zoonoses virais. / Several viral emerging and re-emerging diseases have been described in bats. Environmental changes caused by humans associated with the adaptation of bats to urban areas increase the chance of transmission of these infectious diseases to humans and domestic animals. Coronaviruses studies associated with bats have shown that these hosts act as reservoirs for these viruses, while rotaviruses has been poorly studied in these hosts. This study aimed to determine the occurrence of Rotavirus and Coronavirus in several species of bats from São Paulo State, Brazil, and to perform phylogenetic inferences from Coronavirus RdRp and S genes, as well as from Rotavirus structural and non-structural proteins genes. To this end, RT-PCR followed by DNA sequencing was used. Optimization criterion of distance and identities calculation of the nucleotides and amino acids among the obtained sequences and sequences retrieved from the GenBank were used for phylogenetic and molecular diversity analysis. The occurrence of Coronavirus was 2.95% (9/305) and of Rotavirus was 9.18% (28/305). According to phylogenetic analysis of the RdRp gene, eight strains were classified as Alphacoronavirus. The analysis of the CoV S gene showed that the starins of this study formed a single lineage, segregated from other alphacoronaviruses lineages. Regarding Rotavirus, it was possible to identify the genotype G3-P [3] -IX-RX-CX-MX-AX-NX-T3-E3-H6, similar to that reported in bats, horses and humans. In addition, another strain was classified as G20, similar to the genotype described in humans, while the genotypes found for VP4, NSP3 and NSP5 genes may be classified as new genotypes. These results show that bats may carry infectious agents of public health interest, but further studies are necessary to clarify the role of these animals as reservoirs and infectious sources of these viral zoonoses.
64

Vyhodnocení výrobní měrné emise skleníkových a zátěžových plynů z vybraného chovu prasat

PROKOP, Tomáš January 2019 (has links)
The aim of this final diploma thesis is to evaluate the production specific emission of greenhouse and load gases from selected pig breeding located in Hodětín near Bechyně, South Bohemian Region. The work focuses on the breeding hall, where the pregnant sows and the nursing sows including piglets are located separately. A total of 6 measurements were carried out, which are further compared with each other and with the latest edition of the reference document BREF. The thesis answers the questions and the selected farm is evaluated according to the principles of "Good Agricultural Practice" according to the available BAT techniques listed in the BREF reference document. The season plays a role in assessing and evaluating individual measurements. In winter, ammonia concentration is higher due to less frequent ventilation, causing low temperature and high humidity in the breeding hall. These two basic aspects are described and it is explained why this is the case and why workers approach this solution to the situation. In conclusion, there are methods and recommendations to contribute to lower emissions in selected pig breeding.
65

STAT3 in the Regulation of Brown Adipocyte Differentiation

Cantwell, Marc 01 January 2018 (has links)
Thermogenic fat is a promising target for new therapies in diabetes and obesity. Understanding how thermogenic fat develops is important to develop rational strategies to treat obesity. Previously, we have shown that Tyk2 and STAT3, part of the JAK-STAT pathway, are necessary for proper development of classical brown fat. Using primary preadipocytes isolated from newborn mice we demonstrate that STAT3 is required for differentiation and robust expression of Uncoupling Protein 1. We also confirm that STAT3 is necessary during the early induction stage of differentiation and is dispensable during the later terminal differentiation stage. Without STAT3, the brown preadipocytes have increased apoptosis early in the terminal differentiation phase. We also show that the block in differentiation is caused by an inability of STAT3 knockouts to down regulate β-catenin by the end of the induction phase. Application of Wnt/β-catenin inhibitors or knockdown of β-catenin during the induction phase is sufficient to fully rescue differentiation of brown adipocytes from the Myf5+ lineage, including reduction in apoptosis, restoration of histone acetylation in the UCP1 promoter and enhancer regions, and full restoration of the expression of brown fat genes. Finally, we show that in the beige lineage, STAT3 is also necessary during the induction phase and can be rescued by Wnt/β-catenin inhibitors, although the rescue is not as robust as it is in the Myf5+ lineage.
66

The Ecology and Conservation of the White-Striped Freetail Bat (Tadarida australis) in Urban Environments

Rhodes, Monika, n/a January 2006 (has links)
Of all anthropogenic pressures, urbanisation is one of the most damaging, and is expanding in its influence throughout the world. In Australia, 90% of the human population live in urban centres along the eastern seaboard. Before European settlement in the early 1800s, much of the Australia's East coast was dominated by forests. Many of the forest dependent fauna have had to adapt to forest fragmentation and habitat loss resulting from clearing for urbanisation. However, relatively few studies have investigated the impact of urbanisation on biodiversity. This is especially true for the remaining fauna in large metropolitan areas, such as Melbourne, Sydney and Brisbane. The physical and conceptual context of this thesis is the increasing impact of urbanisation and the potentially threatening factors to forest dependent fauna. Bats were selected because they comprise a third of Australia's mammal species, and therefore form a major component of Australia's biodiversity. Very little is known about the ecology and conservation biology of hollow-dependent bats in general, but particularly in urban environments. The study was conducted in Brisbane, south-east Queensland, one of Australia's most biodiverse regions. More than a third of Australia's bat species occur in this region. A large insectivorous bat, the white-striped freetail bat (Tadarida australis), was selected to study two key resources in this urban area - hollow availability and foraging habitat. This thesis also examined if artificial roost habitat could provide temporary roosts for white-striped freetail bats and other insectivorous bats and assessed whether these bat boxes can be used as a conservation tool in urban environments where natural hollow-availability is limited. The white-striped freetail bat is an obligate hollow-dweller and roosted largely in hollows of old or dead eucalypts throughout Brisbane's urban matrix. These roost trees harboured significantly more additional hollow-dependent species compared to control trees of similar age, height, and tree diameter. Roost cavities inside trees often exceeded 30 cm in diameter. Furthermore, maternity colonies used cavities of hollow trunks, which often extended into major branches, to roost in big numbers. Therefore artificial alternatives, such as small bat boxes, may provide temporary shelter for small roosting groups, but are unlikely to be suitable substitutes for habitat loss. Although five bat species used bat boxes during this study, the white-striped freetail bat was not attracted into bat boxes. Roost-switching behaviour was then used to quantify associations between individual white-striped freetail bats of a roosting group. Despite differences in gender and reproductive seasons, the bats exhibited the same behaviour throughout three radio-telemetry periods and over 500 bat-days of radio-tracking: each roosted in separate roosts, switched roosts very infrequently, and associated with other tagged bats only at a communal roost. Furthermore, the communal roost exhibited a hub of socialising between members of the roosting group especially at night, with vocalisation and swarming behaviour not found at any of the other roosts. Despite being spread over a large geographic area (up to 200 km2), each roost was connected to others by less than three links. One roost (the communal roost) defined the architecture of the network because it had the most links. That the network showed scale-free properties has profound implications for the management of the habitat trees of this roosting group. Scale-free networks provide high tolerance against stochastic events such as random roost removals, but are susceptible to the selective removal of hub nodes, such as the communal roost. The white-striped freetail bat flew at high speed and covered large distances in search for food. It foraged over all land-cover types found in Brisbane. However, its observed foraging behaviour was non-random with respect to both spatial location and the nature of the ground-level habitat. The main feeding areas were within three kilometers of the communal roost, predominantly over the Brisbane River flood plains. As the only mammal capable of flight, bats can forage above fragmented habitats. However, as this study showed, hollow-dependent insectivorous bats, including free-tailed bats, are specialised in their roosting requirements. The ongoing protection of hollow-bearing trees, and the ongoing recruitment of future hollow-bearing trees, is essential for the long-term conservation of these animals in highly fragmented landscapes. Furthermore, loss of foraging habitat is still poorly understood, and should be considered in the ongoing conservation of bats in urban environments.
67

Braking Availability Tester (BAT) for Winter Runway

Joshi, Kamal January 2013 (has links)
This thesis is concerned with the development of a new measurement device for the realistic assessment of braking capability of landing airplanes for winter runways. Landing represents one of the most safety-critical phases of aircraft operation. Aircraft runway excursion incidents occur due to the unpredictability of the runway pavement condition. This is especially true during winter time when the runway is often covered by deformable contaminants. Several accidents are discussed that list the deteriorated condition of the runway pavement and the inability to accurately report this condition as the main causes for the excursions. The accuracy of the approaches currently adopted by the airport authorities around the world to monitor the condition of the runway pavement are evaluated. The conventional and current practice of runway condition monitoring is focused on identifying the maximum tire-pavement frictional drag mu value and often neglects the characteristics of actual aircraft brake control system as well as the comprehensive effects coming from various factors such as deformable contaminants on the winter runway. The braking availability tester discussed here is designed to take a different approach for the realistic assessment of braking availability of landing aircrafts. The main idea of this device is to mimic the braking operation of actual aircrafts as closely as possible by incorporating the same brake mechanism and the brake control system used in existing aircrafts. The architecture of the device from the ground-up including the suite of sensors, the structure of the wheel, important actuators, and the real-time brake control system are discussed in detail. More importantly, the operational principles of the braking availability tester (BAT) are outlined which help one understand how the system works together. A new method to quantify the braking availability on the runway using the BAT is explained. The testing and data collection strategy for implementing this technique is also outlined. Additionally, the results from preliminary tests are presented to verify the functionality of the BAT. The results are used to verify that the BAT operates with the brake control system of an aircraft. Finally, experimental data sets from dry and contaminated pavement testing are presented to show the effect of different weather conditions on the operation of the BAT.
68

Deskription der Schwermetallgehalte in Knochen, Organen und Haaren von Fledermäusen (Chiroptera) im Zeitraum 1987 bis 1999 / Description of heavy metal concentrations in bone, tissue and hair of bats (Chiroptera) within the period 1987 - 1999

Hartmann, Rainer 30 January 2001 (has links)
No description available.
69

Braking Availability Tester (BAT) for Winter Runway

Joshi, Kamal January 2013 (has links)
This thesis is concerned with the development of a new measurement device for the realistic assessment of braking capability of landing airplanes for winter runways. Landing represents one of the most safety-critical phases of aircraft operation. Aircraft runway excursion incidents occur due to the unpredictability of the runway pavement condition. This is especially true during winter time when the runway is often covered by deformable contaminants. Several accidents are discussed that list the deteriorated condition of the runway pavement and the inability to accurately report this condition as the main causes for the excursions. The accuracy of the approaches currently adopted by the airport authorities around the world to monitor the condition of the runway pavement are evaluated. The conventional and current practice of runway condition monitoring is focused on identifying the maximum tire-pavement frictional drag mu value and often neglects the characteristics of actual aircraft brake control system as well as the comprehensive effects coming from various factors such as deformable contaminants on the winter runway. The braking availability tester discussed here is designed to take a different approach for the realistic assessment of braking availability of landing aircrafts. The main idea of this device is to mimic the braking operation of actual aircrafts as closely as possible by incorporating the same brake mechanism and the brake control system used in existing aircrafts. The architecture of the device from the ground-up including the suite of sensors, the structure of the wheel, important actuators, and the real-time brake control system are discussed in detail. More importantly, the operational principles of the braking availability tester (BAT) are outlined which help one understand how the system works together. A new method to quantify the braking availability on the runway using the BAT is explained. The testing and data collection strategy for implementing this technique is also outlined. Additionally, the results from preliminary tests are presented to verify the functionality of the BAT. The results are used to verify that the BAT operates with the brake control system of an aircraft. Finally, experimental data sets from dry and contaminated pavement testing are presented to show the effect of different weather conditions on the operation of the BAT.
70

Causes and Consequences of Fission-Fusion Dynamics in Female Northern Long-Eared Bats, Myotis septentrionalis

Patriquin, Krista 23 May 2012 (has links)
Individual costs and benefits of living in groups vary with group size, stability, and composition. Investigations of these features of group living have lead to the recognition of a variety of social structures. Although many studies have examined social structure in animals with long-term, stable groups, little is known about groups with highly variable group size and composition, such as fission-fusion dynamics. In this thesis I examined the causes and consequences of fission-fusion dynamics by exploring the socioecology of female northern long-eared bats, Myotis septentrionalis. Like many temperate bats, female northern long-eared bats show natal philopatry to summer areas. During this time, they live in groups with fission-fusion dynamics as individuals move among a network of roosts and roost-groups. To examine the causes of fission-fusion dynamics, I examined why females switch roosts. To address the consequences of these dynamics, I asked whether females could form stable relationships, and what factors might explain these relationships. I was able to identify the possible causes and consequences of fission-fusion dynamics that had not yet been explored in bats. I demonstrated that fission-fusion dynamics may be explained, at least in part, by changes in ambient conditions that prompt frequent roost-switching. Despite the highly dynamic nature of these groups, females formed long-term social relationships that were based in part on age and genetic relatedness. These findings have potential consequences for the evolution of social behaviour within groups, such as cooperation and nepotism. My work also raised several questions that require further examination to fully understand the evolution of fission-fusion dynamics. For example, the question remains whether species or sympatric groups of conspecifics with different degrees of roost-switching show the same social structure. By answering these questions, we can gain a better understanding of the causes and consequences of fission-fusion dynamics across species of bats. Once this is achieved, we can then look for parallels with other taxa to answer questions about the evolution of these dynamic systems.

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