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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.
211

Influência da comunidade microbiana do solo no estabelecimento de sauveiros iniciais de Atta sexdens rubropilosa Forel, 1908 (Hymenoptera: Formicidae) / Influence of soil microbial community on the establishment of ant nests of Atta sexdens rubropilosa Forel, 1908 (Hymenoptera: Formicidae)

Rodrigues, Ohana Daroszewski 18 January 2008 (has links)
O presente trabalho teve como objetivo comparar o estabelecimento de sauveiros iniciais em duas áreas de cultivo de cana-de-açúcar com solos de diferentes texturas (médio-argilosa e argilosa) e verificar a influência dos fatores químicos e microbiológicos desses solos no estabelecimento de formigueiros iniciais de A. sexdens rubropilosa. Os sauveiros iniciais foram demarcados após a penetração das içás no solo a partir da revoada. As avaliações foram conduzidas após 40 dias da revoada e foram mantidas semanalmente, por um período de 120 dias ou até a reabertura do canal inicial dos ninhos para forrageamento. No experimento de laboratório, as rainhas foram acondicionadas em potes com solo das duas áreas em 25 ± 2ºC e UR 70%. As avaliações de laboratório foram feitas seguindo-se a mesma metodologia de campo, verificando a atividade dos sauveiros. Os sauveiros mortos foram descartados e as rainhas, foram utilizadas para isolamento de microrganismos para associá-los à causa da morte. As análises dos fatores químicos e microbiológicos do solo incluíram macro e micronutrientes, carbono da biomassa microbiana, contagem do número mais provável de fungos, bactérias e contagem de unidades formadoras de colônias de actinomicetos. Houve uma maior sobrevivência dos sauveiros iniciais de A. sexdens rubropilosa em solos contendo textura argilosa do que médio-argilosa em laboratório. Nas áreas com solo de textura argilosa e médio-argilosa, a sobrevivência dos ninhos foi de 47,8 e 26,7%, respectivamente. No campo, por sua vez, não foram observadas diferenças no estabelecimento dos sauveiros iniciais para as duas áreas de cana-de-açúcar. O carbono da biomassa microbiana bem como o número mais provável de bactérias foi superior no solo de textura médio-argilosa comparativamente ao de textura argilosa. Diferentemente dos resultados de laboratório, os estudos de campo indicaram que à ação dos microrganismos do solo no estabelecimento de sauveiros novos de A. sexdens rubropilosa não foi tão expressiva. / The objective of the present study was to compare the establishment of new ant nests in two sugarcane growing areas with different soil types (sandy clay and clay) and to verify the influence of chemical and microbiological soil factors on nest establishment. In order to determine nest establishment, initial ant nests were marked and accompanied with other activities immediately after nuptial flight. Evaluations for verification of nest establishment were made weekly after 40 days for the period of 120 days. In laboratory experiment, mated queens collected from the two areas with different soils were maintained in plastic pots containing soil from respective areas at 25 ± 2ºC and 70% RH. To verify activities of the ants, a method similar to the one used to the field study was adopted. Dead ants were discarded while dead queens were used for isolation of associated microorganisms to determine the cause of mortality. The analysis of chemical and microbiological factors of the soil determined macro and micro-nutrients including carbon biomass, the most probable number of fungi, bacteria and counting of the colony forming units of the actinomycetes. The establishment of new ant nests occurred significantly more in the sandy clay soil than clay soil in laboratory. In the areas of sandy clay and clay soil the establishments were 47.8 and 26.7%, respectively. In the field was not observed difference in the establishment of new ant nest in both areas. The carbon biomass and most probable number of bacteria were significantly higher in the sandy clay soil when compared with clay soil area. Differently from laboratory results, the field studies indicated that the establishment of new ant nests of A. sexdens rubropilosa was not only based on the soil microrganism.
212

Selection of larvae for queen rearing by workers in the honey bee (Apis mellifera L.) − nepotism or different maternal supply?

AL-Kahtani, Saad Naser Saad 15 August 2011 (has links)
Natürliche Selektion bevorzugt effiziente Zusammenarbeit innerhalb von eusozialen Kolonien. Dennoch kann bei polyandrischen Arten die Aufzucht von Königinnen Konflikte auslösen. Es wird vermutet, dass Honigbienen nepotistisch bei der Königinnenaufzucht agieren. Bienen sind in der Lage zwischen verschiedenen verwandten Individuen zu unterscheiden. Die bisher publizierten Daten sind aber widersprüchlich. In meiner Untersuchung zeigte sich, dass standardisiert aufgezogene Larven durch verwandte Arbeitsbienen nicht signifikant bevorzugt werden, aber dass ein höheres Gewicht der Eier, aus denen die Larven geschlüpft sind, ihre Chancen als Königin aufgezogen zu werden signifikant erhöhen. Ein hohes Eigewicht führte außerdem zu einer zwar nicht signifikanten, aber tendenziellen Erhöhung von Fitness Eigenschaften der resultierenden Königinnen. Probleme, Nepotismus eindeutig zu belegen, sind möglicherweise dadurch verursacht, dass die Verwandtschafts-Präferenz bestimmter Individuen nicht in eine Kolonie-Entscheidung überführt werden kann. Ich habe deshalb – mit molekulargenetischen Methoden – die Verwandtschaft der Larven, die als Königinnen aufgezogen werden sollen, mit jener der Pflege-Bienen, die deren Aufzucht initiierten, vergliechen. In fünf Kolonien, deren Königinnen mit jeweils drei Drohnen von drei verschiedenen Herkünften besamt wurden, fand ich keine Präferenz von Arbeitsbienen für ihre nah-verwandten Geschwister. Dafür zeigten sich signifikante Unterschiede bezüglich Präferenz für Larven der drei Drohnen-Herkünfte. Dies kann so interpretiert werden, dass Honigbienen in der Lage sind, zwischen genetischen Varianten zu unterscheiden, aber dass diese Fähigkeit nicht für Nepotismus genutzt wird. In einem natürlichen, durch Mehrfachpaarung genetisch variablen, aber mindestens zu 25 % verwandten Volk, ist eine genetisch oder umwelt- (maternal) induzierte Attraktivität, und nicht der Grad der Verwandtschaft, das zentrale Selektionskriterium in. / Natural selection favours an efficient cooperation within eusocial colonies. However, in polyandrous species, queen rearing may provide some conflict. Worker bees are assumed to play a nepotistic role during the queen-rearing phase by preferring more closely related larvae. Honeybee workers were found to be able to discriminate between different related individuals, but published data are inconsistent. Here in my study I show that larvae reared on a standardized basis were not significantly preferred by related worker bees, but that a higher egg weight – from which the larvae originated – significantly increased the chance to receive a royalty treatment and showed a tendency to correlate positively with fitness traits of the resulting queen. Queen rearing results from a colony decision, and this involves many workers. Consequently any lack of a nepotism which is proved may be due to the fact that relatedness-driven kin preference of individuals cannot be applied to a colony decision. In view of this, using DNA fingerprinting, I also tested the relatedness of larvae to be reared as queens and those nursing worker bees which initiated the queen−rearing process. In five colonies, each inseminated with three drones from three different origins, I did not observe any preference of worker bees for their closely related sib for queen rearing, but I did find significant differences with respect to the preference of worker bees for larvae from the three drone origins. Our data provide evidence that honey bees have the ability to discriminate genetic differences, but they do not use it for nepotism. In a natural, diverse – but always at least 25%-related – framework within a colony, genetically or environmentally driven attractiveness but not relatedness represents the key criteria for selecting larvae for gyne production.
213

Organizational changes: a case study of the Queen Elizabeth Hospital.

January 1994 (has links)
by Lau Cheung Hoo, Gary. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 66-68). / ABSTRACT --- p.i / ACKNOWLEDGEMENT --- p.i i / TABLE OF CONTENTS --- p.iii / Chapter / Chapter I. --- INTRODUCTION --- p.1 / Method of Study --- p.3 / Chapter II. --- REASONS FOR CHANGES --- p.5 / External Forces --- p.6 / Internal Forces --- p.7 / Chapter III. --- CHANGES UNDER THE HOSPITAL AUTHORITY --- p.10 / Establishment of the Hospital Authority --- p.10 / Changes Under the Hospital Authority --- p.12 / Chapter IV. --- STRATEGIES FOR THE PLANNED CHANGE --- p.17 / Structural Approaches to Changes --- p.17 / Technological Approaches to Changes --- p.18 / People Approaches to Changes --- p.19 / Comments --- p.22 / Chapter V. --- CASE STUDY: QUEEN ELIZABETH HOSPITAL --- p.24 / Background Information --- p.24 / Mission of QEH --- p.25 / Major Changes --- p.26 / Resistance and Problems --- p.29 / Results to-date --- p.35 / Overall Evaluation and Summary View --- p.43 / Chapter VI. --- CONCLUSION --- p.50 / APPENDIX --- p.55 / BIBLIOGRAPHY --- p.67
214

Ecology and reproduction of neotropical soil-feeding termites from the Termes group

Hellemans, Simon 24 April 2019 (has links) (PDF)
The traditional view of a lifelong monogamy between a king and a queen has recently been challenged in termites. In several species, multiple parthenogenetically-produced secondary queens replace the primary queen and mate with the primary king; this strategy is referred to as “Asexual Queen Succession” (AQS). The aim of my thesis was to investigate the modalities of reproduction and the ecology of neotropical soil-feeding termites from the Termitinae, with a focus on the inquiline termite Cavitermes tuberosus in the Termes group.In the first axis, we investigated the modalities of reproduction of C. tuberosus. (i) AQS is the main reproductive strategy of this species. (ii) The evolution of AQS requires the propensity of parthenogens to develop into neotenic queens. In C. tuberosus, secondary queens develop from a developmental stage of “aspirants” which participate to the social tasks usually undertaken by workers, as long as the primary queen is alive. (iii) In AQS species, a female-biased sex ratio is expected in the dispersing reproductives. In C. tuberosus, sex ratio varies among years and according to the type of reproductives, and the population sex ratio is balanced. These results raise hints on queen-king conflict over the sex ratio.In the second axis, we described the ecology and symbioses of C. tuberosus. (iv) Wolbachia, an endosymbiotic bacterium mainly known for manipulating the reproduction of arthropods in order to enhance its own transmission, infects all individuals in societies. This bacterium, particularly abundant in a gut-associated bacteriome, may play a role in the nutrition of C. tuberosus; both partners would have evolved a mutualistic symbiosis. (v) Inquiline termites live in a nest built by other termite species and do not forage outside. Physico-chemical measures and microbiota sequencing revealed that C. tuberosus is a generalist nest-feeder.Finally, we expanded our study of the breeding systems in the phylogenetic proximity of C. tuberosus. (vi) We described Palmitermes impostor, a new genus and species as a sister-group to the genus Cavitermes. (vii) AQS is the main reproductive strategy in P. impostor, and queens of Spinitermes trispinosus and Inquilinitermes inquilinus are able to reproduce parthenogenetically. Therefore, it appears likely that the conditional use of sexual and asexual reproductions is a preadaptation common to the whole Termes group, and that it evolved into a stable element of their breeding system at least in some species.Overall, our results open new perspectives in the understanding of reproductive strategies in termites and their relationships with their bacterial symbionts. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
215

Representing a Nation of Tailors and Cobblers : A Study of Bulstrode Whitelocke´s <em>Journal of the Swedish Embassy,</em> 1653-1654

Martin, Rebecca January 2007 (has links)
<p>In November 1653, a vessel arrived in the harbour town of Gothenburg, on the west coast of the Protestant monarchy of Sweden. Aboard the ship was the newly appointed English Ambassador Extraordinary, Bulstrode Whitelocke (1605-1675); jurist, Puritan and avid diary keeper. In his journal, Whitelocke noted down the entirety of what he was to experience during his stay in Sweden. From the heaps of papers he produced over his lifetime, he later edited this particular record under the title <em>Journal of the Swedish Embassy</em>. Spanning between 1653 and 1654, the pages of the journal contains information of the most mundane kind, as well as eye witness accounts of what must be recognised as a very interesting part of European history. More so, it reveals Whitelocke’s views on the political questions of his time, mainly presented through conversations with important actors from Swedish society, such as Queen Christina, Lord High Chancellor Axel Oxenstierna, and the Archbishop of Uppsala, Johannes Canuti Lenaeus. In the eyes of the Swedes, Whitelocke became a representative not only of the new Commonwealth of England, but of the new ideas that had formed the basis of its government. As such, he was often made to explain the conduct of his country men, as well as defend the recent events in England. Thus, through these recorded exchanges, an image of Whitelocke´s representation and of his views regarding the changes in England emerges from the pages. This Masters Thesis will analyse this image, as well as discuss Whitelocke’s political views, both practical and ideological, at the time of his embassy to Sweden.</p>
216

Representing a Nation of Tailors and Cobblers : A Study of Bulstrode Whitelocke´s Journal of the Swedish Embassy, 1653-1654

Martin, Rebecca January 2007 (has links)
In November 1653, a vessel arrived in the harbour town of Gothenburg, on the west coast of the Protestant monarchy of Sweden. Aboard the ship was the newly appointed English Ambassador Extraordinary, Bulstrode Whitelocke (1605-1675); jurist, Puritan and avid diary keeper. In his journal, Whitelocke noted down the entirety of what he was to experience during his stay in Sweden. From the heaps of papers he produced over his lifetime, he later edited this particular record under the title Journal of the Swedish Embassy. Spanning between 1653 and 1654, the pages of the journal contains information of the most mundane kind, as well as eye witness accounts of what must be recognised as a very interesting part of European history. More so, it reveals Whitelocke’s views on the political questions of his time, mainly presented through conversations with important actors from Swedish society, such as Queen Christina, Lord High Chancellor Axel Oxenstierna, and the Archbishop of Uppsala, Johannes Canuti Lenaeus. In the eyes of the Swedes, Whitelocke became a representative not only of the new Commonwealth of England, but of the new ideas that had formed the basis of its government. As such, he was often made to explain the conduct of his country men, as well as defend the recent events in England. Thus, through these recorded exchanges, an image of Whitelocke´s representation and of his views regarding the changes in England emerges from the pages. This Masters Thesis will analyse this image, as well as discuss Whitelocke’s political views, both practical and ideological, at the time of his embassy to Sweden.
217

Predicting waterfowl distribution in the central Canadian arctic using remotely sensed habitat data

Conkin, John Alexander 22 February 2011
Knowledge of a species habitat-use patterns, as well as an understanding of the distribution and spatial arrangement of preferred habitat, is essential for developing comprehensive management or conservation plans. This information is absent for many species, especially so for those living or breeding in remote areas. Habitat-use models can assist in delineating specific habitat requirements or preferences of a species. When coupled with geographic information system (GIS) technology, such models are now frequently used to identify important habitats and to better define species distributions.<p> Recent and persistent warming, widespread contaminant accumulation, and intensifying land use in the arctic heighten the urgent need for better information about spatial distributions and key habitats for northern wildlife. Here, I used aerial survey and corresponding digital land cover data to investigate breeding-ground distributions and landscape-level habitat associations of greater white-fronted geese (Anser albifrons frontalis), small Canada geese (Branta canadensis hutchinsii), tundra swans (Cygnus columbianus), king eiders (Somateria spectabilis), and long-tailed ducks (Clangula hyemalis) in the Queen Maud Gulf Migratory Bird Sanctuary and the Rasmussen Lowlands, Nunavut, Canada.<p> First, I addressed the sensitivity of inferences about predicting waterfowl presence on the basis of the amounts and configurations of arctic habitat sampled at four scales. Detection and direction of relationships of focal species with land cover covariates often varied when land cover data were analysed at different scales. For instance, patterns of habitat use for a given species at one spatial scale may not necessarily be predicted from patterns arising from measurements taken at other scales. Thus, inference based on species-habitat patterns from some scales may lead to inaccurate depictions of how habitat influences species. Potential variation in species-environment relationships relative to spatial scale needs to be acknowledged by wildlife managers to avoid inappropriate management decisions.<p> Second, I used bird presence determined during aerial surveys and classified satellite imagery to develop species-habitat models for describing breeding-ground distributions and habitat associations of each focal species. Logistic regression models identified lowland land cover types to be particularly important for the species considered. I used the Receiver Operating Characteristic (ROC) technique and the area under the curve (AUC) metric to evaluate the precision of models, where the AUC is equal to the probability that two randomly selected encounter and non-encounter survey segments will be discriminated as such by the model. In the Queen Maud Gulf, AUC values indicated reasonable model discrimination for white-fronted geese, Canada geese, and tundra swans (i.e, AUC > 0.7). Precision of species-habitat models for king eiders and long-tailed ducks was lower than other species considered, but predict encounters and non-encounters significantly better than the null model. For all species, precision of species-habitat models was lower in the Rasmussen Lowlands than in the Queen Maud Gulf, although discrimination ability remained significantly better than the null model for three of five species (king eider and long-tailed duck models performed no better than the null model here).<p> Finally, I simulated anticipated environmental change (i.e., climate warming) in the arctic by applying species-habitat models to manipulated land cover data, and then predicted distributional responses of focal species. All species considered in this research exhibited some association to lowland cover types; white-fronted geese, Canada geese, and tundra swans in particular demonstrated strong affinity toward these habitats. Others authors predict lowland cover types to be most affected by warming. Reductions of wet sedge, hummock, and tussock graminoid cover predicted in this simulation, predominantly along the coast of the Queen Maud Gulf study area and in central areas of the Rasmussen Lowlands, suggest that distributions of species dependant on these lowland habitats will be significantly reduced, if predictions about warming and habitat loss prove to be correct. Research presented here provides evidence that modeling of species distributions using landscape-level habitat data is a tractable method to identify habitat associations, to determine key habitats and regions, and to forecast species responses to environmental changes.
218

The Legacy of 48 Abell: Tales From A Gentrifying Neighbourhood

Van Eyk, Michelle January 2010 (has links)
Constructed in 1886 by Mr. John Abell, the former engine and machine works factory at 48 Abell Street is located near Queen and Dufferin Streets in Toronto, Ontario. This 100,000 square foot heavy timber and red brick building has housed approximately 80 live/work studios since the 1980’s. Recently, rapid gentrification and intensive development proposals in the West Queen West neighbourhood have threatened its existence as an authentic artistic incubator. In a series of chronicles, this thesis documents the history of John Abell and the neighbourhood surrounding his former factory from the late 19th century to present day. Woven into this narrative are the author’s own stories of living in a loft at 48 Abell Street, observing the transformation of the neighbourhood and responding to potential eviction from her home. When the community rallies to the building’s defense, 48 Abell becomes the central figure in a battle over land development with the City and real estate developers in which the key issue is the cultural value of heritage buildings and protection of live/work spaces. Research in the form of mapping and data collection shows the concentration of the arts in the area known as the Queen West Triangle has been a catalyst for gentrification. The resulting displacement of arts production space and low-income residents due to escalating land values is an unintended and sobering reality challenging the current orthodoxy of ‘creative city’ movements in North America.
219

The Legacy of 48 Abell: Tales From A Gentrifying Neighbourhood

Van Eyk, Michelle January 2010 (has links)
Constructed in 1886 by Mr. John Abell, the former engine and machine works factory at 48 Abell Street is located near Queen and Dufferin Streets in Toronto, Ontario. This 100,000 square foot heavy timber and red brick building has housed approximately 80 live/work studios since the 1980’s. Recently, rapid gentrification and intensive development proposals in the West Queen West neighbourhood have threatened its existence as an authentic artistic incubator. In a series of chronicles, this thesis documents the history of John Abell and the neighbourhood surrounding his former factory from the late 19th century to present day. Woven into this narrative are the author’s own stories of living in a loft at 48 Abell Street, observing the transformation of the neighbourhood and responding to potential eviction from her home. When the community rallies to the building’s defense, 48 Abell becomes the central figure in a battle over land development with the City and real estate developers in which the key issue is the cultural value of heritage buildings and protection of live/work spaces. Research in the form of mapping and data collection shows the concentration of the arts in the area known as the Queen West Triangle has been a catalyst for gentrification. The resulting displacement of arts production space and low-income residents due to escalating land values is an unintended and sobering reality challenging the current orthodoxy of ‘creative city’ movements in North America.
220

Predicting waterfowl distribution in the central Canadian arctic using remotely sensed habitat data

Conkin, John Alexander 22 February 2011 (has links)
Knowledge of a species habitat-use patterns, as well as an understanding of the distribution and spatial arrangement of preferred habitat, is essential for developing comprehensive management or conservation plans. This information is absent for many species, especially so for those living or breeding in remote areas. Habitat-use models can assist in delineating specific habitat requirements or preferences of a species. When coupled with geographic information system (GIS) technology, such models are now frequently used to identify important habitats and to better define species distributions.<p> Recent and persistent warming, widespread contaminant accumulation, and intensifying land use in the arctic heighten the urgent need for better information about spatial distributions and key habitats for northern wildlife. Here, I used aerial survey and corresponding digital land cover data to investigate breeding-ground distributions and landscape-level habitat associations of greater white-fronted geese (Anser albifrons frontalis), small Canada geese (Branta canadensis hutchinsii), tundra swans (Cygnus columbianus), king eiders (Somateria spectabilis), and long-tailed ducks (Clangula hyemalis) in the Queen Maud Gulf Migratory Bird Sanctuary and the Rasmussen Lowlands, Nunavut, Canada.<p> First, I addressed the sensitivity of inferences about predicting waterfowl presence on the basis of the amounts and configurations of arctic habitat sampled at four scales. Detection and direction of relationships of focal species with land cover covariates often varied when land cover data were analysed at different scales. For instance, patterns of habitat use for a given species at one spatial scale may not necessarily be predicted from patterns arising from measurements taken at other scales. Thus, inference based on species-habitat patterns from some scales may lead to inaccurate depictions of how habitat influences species. Potential variation in species-environment relationships relative to spatial scale needs to be acknowledged by wildlife managers to avoid inappropriate management decisions.<p> Second, I used bird presence determined during aerial surveys and classified satellite imagery to develop species-habitat models for describing breeding-ground distributions and habitat associations of each focal species. Logistic regression models identified lowland land cover types to be particularly important for the species considered. I used the Receiver Operating Characteristic (ROC) technique and the area under the curve (AUC) metric to evaluate the precision of models, where the AUC is equal to the probability that two randomly selected encounter and non-encounter survey segments will be discriminated as such by the model. In the Queen Maud Gulf, AUC values indicated reasonable model discrimination for white-fronted geese, Canada geese, and tundra swans (i.e, AUC > 0.7). Precision of species-habitat models for king eiders and long-tailed ducks was lower than other species considered, but predict encounters and non-encounters significantly better than the null model. For all species, precision of species-habitat models was lower in the Rasmussen Lowlands than in the Queen Maud Gulf, although discrimination ability remained significantly better than the null model for three of five species (king eider and long-tailed duck models performed no better than the null model here).<p> Finally, I simulated anticipated environmental change (i.e., climate warming) in the arctic by applying species-habitat models to manipulated land cover data, and then predicted distributional responses of focal species. All species considered in this research exhibited some association to lowland cover types; white-fronted geese, Canada geese, and tundra swans in particular demonstrated strong affinity toward these habitats. Others authors predict lowland cover types to be most affected by warming. Reductions of wet sedge, hummock, and tussock graminoid cover predicted in this simulation, predominantly along the coast of the Queen Maud Gulf study area and in central areas of the Rasmussen Lowlands, suggest that distributions of species dependant on these lowland habitats will be significantly reduced, if predictions about warming and habitat loss prove to be correct. Research presented here provides evidence that modeling of species distributions using landscape-level habitat data is a tractable method to identify habitat associations, to determine key habitats and regions, and to forecast species responses to environmental changes.

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