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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.
131

Artificial Grammar Recognition Using Spiking Neural Networks

Cavaco, Philip January 2009 (has links)
<p>This thesis explores the feasibility of Artificial Grammar (AG) recognition using spiking neural networks. A biologically inspired minicolumn model is designed as the base computational unit. Two network topographies are defined with different ideologies. Both networks consists of minicolumn models, referred to as nodes, connected with excitatory and inhibitory connections. The first network contains nodes for every bigram and trigram producible by the grammar’s finite state machine (FSM). The second network has only nodes required to identify unique internal states of the FSM. The networks produce predictable activity for tested input strings. Future work to improve the performance of the networks is discussed. The modeling framework developed can be used by neurophysiological research to implement network layouts and compare simulated performance characteristics to actual subject performance.</p>
132

Effects of natural gas development on three grassland bird species in CFB Suffield, Alberta, Canada

Hamilton, Laura 06 1900 (has links)
I investigated the effect of energy sector development and introduced crested wheatgrass (Agropyron cristatum) on grassland birds on Canadian Forces Base Suffield. I conducted point counts and mapped breeding territories in 2007 and 2008 for Savannah sparrows (Passerculus sandwichensis), chestnut-collared longspurs (Calcarius ornatus), and Spragues pipits (Anthus spragueii). I found that Savannah sparrows favored areas with taller vegetation, human disturbances and crested wheatgrass in both years. Longspurs used shorter vegetation and in were tolerant of disturbance. Crested wheatgrass was avoided by longspurs in both years. Pipit territories contained similar vegetation to longspurs, were sensitive to disturbance, and avoided placing territories in areas containing crested wheatgrass or trails in both years. Well sites, pipelines and junctions were not avoided by the three species. My research suggests that reducing the number of trails and the spread of crested wheatgrass will increase habitat availability for sensitive species of grassland birds. / Ecology
133

Building Nest

Carter, Laura 03 August 2007 (has links)
“What does it mean, to make a genuine generalization, to create an objective concrete abstraction of a phenomenon?”—Evald Ilyenkov. As Guy Debord writes in his Society of the Spectacle, “the lack of general historical life also means that individual life as yet has no history.” These poems are my process of coming to understand history, and many of them are critiques of histories per se. If, as Frank O’Hara writes, “these anxieties remain erect,” they also shape the poems that I have written here. I want to be in dialogue with the spectacle that shapes postmodernism. I want to live in communication with the memories of events that have shaped my speech over the years. The title is a struggle to regain a home while not forgetting the displacement of the proverbial poet, a poet to whom I am forever indebted and probably likely to become.
134

Nesting and duckling ecology of white-winged scoters (<i>melanitta fusca deglandi</i>) at Redberry Lake, Saskatchewan

Traylor, Joshua James 01 December 2003
Population surveys indicate a declining trend in abundance for the scoter genus at the continental level. Little is known about changes in life history traits responsible for the recent population decline of white-winged scoters (<i>Melanitta fusca deglandi</i>, hereafter scoters). Therefore, I studied nesting and duckling ecology of scoters at Redberry Lake, Saskatchewan, Canada during summers 2000-2001 when I found 198 nests. To examine nest-site selection, I compared habitat features between successful nests, failed nests, and random sites. Discriminant function analysis differentiated habitat features, measured at hatch, between successful nests, failed nests, and random sites; lateral (r = 0.65) and overhead (r = 0.35) concealment were microhabitat variables most correlated with canonical discriminant functions. I also modeled daily survival rate (DSR) of nests as a function of year, linear and quadratic trends with nest age, nest initiation date, and seven microhabitat variables. Nest survival from a time constant model (i.e., Mayfield nest success estimate) was 0.35 (95% CL: 0.27, 0.43). Estimates of nest success were lower than those measured at Redberry Lake in the 1970s and 1980s. In addition to nest survival increasing throughout the laying period and stabilizing during incubation, nest survival showed positive relationships with nest concealment and distance to water, and a negative relationship with distance to edge. Considering these factors, a model-averaged estimate of nest survival was 0.24 (95% CL: 0.09, 0.42). I conclude that scoters selected nesting habitat adaptively because (1) successful sites were more concealed than failed sites, (2) nest sites (i.e., successful and failed) had higher concealment than random sites, and (3) nest sites were on islands where success is greater than mainland. I then estimated duckling and brood survival with Cormack-Jolly-Seber models, implemented in Program Mark, from observations of 94 and 664 individually marked adult hens and ducklings, respectively. I tested hypotheses about duckling survival and (1) hatch date, (2) initial brood size at hatch, (3) duckling size and body condition at hatch, (4) offspring sex, (5) maternal female size and body condition at hatch, and (6) weather conditions within one week of hatching. Most mortality occurred during the first six days of duckling age. Variation in both duckling and brood survival were best modeled with effects of hatch date and initial brood size, while effects of female condition, female size, duckling size, and duckling condition were inconsistent. Survival probability clearly decreased with advancing hatch date and increased with larger initial brood sizes. Effects of weather and offspring sex in 2001, the only year such information was collected, suggested survival was negatively related to poor weather, but sex of ducklings, beyond size-related differences (i.e., sexual-size dimorphism), was unimportant. Estimates of survival to 28 days of age (30-day period), whether for ducklings (0.016, 0.021) or broods (0.084, 0.138) in 2000 or 2001, respectively, are the lowest of published studies and first for scoter broods in North America. I suspect intense gull predation shortly after hatch had the largest influence on duckling survival. Further research is needed to ascertain if low nesting success and duckling survival as well as other life cycle components are limiting scoter populations locally and throughout the rest of their breeding range.
135

Nesting and duckling ecology of white-winged scoters (<i>melanitta fusca deglandi</i>) at Redberry Lake, Saskatchewan

Traylor, Joshua James 01 December 2003 (has links)
Population surveys indicate a declining trend in abundance for the scoter genus at the continental level. Little is known about changes in life history traits responsible for the recent population decline of white-winged scoters (<i>Melanitta fusca deglandi</i>, hereafter scoters). Therefore, I studied nesting and duckling ecology of scoters at Redberry Lake, Saskatchewan, Canada during summers 2000-2001 when I found 198 nests. To examine nest-site selection, I compared habitat features between successful nests, failed nests, and random sites. Discriminant function analysis differentiated habitat features, measured at hatch, between successful nests, failed nests, and random sites; lateral (r = 0.65) and overhead (r = 0.35) concealment were microhabitat variables most correlated with canonical discriminant functions. I also modeled daily survival rate (DSR) of nests as a function of year, linear and quadratic trends with nest age, nest initiation date, and seven microhabitat variables. Nest survival from a time constant model (i.e., Mayfield nest success estimate) was 0.35 (95% CL: 0.27, 0.43). Estimates of nest success were lower than those measured at Redberry Lake in the 1970s and 1980s. In addition to nest survival increasing throughout the laying period and stabilizing during incubation, nest survival showed positive relationships with nest concealment and distance to water, and a negative relationship with distance to edge. Considering these factors, a model-averaged estimate of nest survival was 0.24 (95% CL: 0.09, 0.42). I conclude that scoters selected nesting habitat adaptively because (1) successful sites were more concealed than failed sites, (2) nest sites (i.e., successful and failed) had higher concealment than random sites, and (3) nest sites were on islands where success is greater than mainland. I then estimated duckling and brood survival with Cormack-Jolly-Seber models, implemented in Program Mark, from observations of 94 and 664 individually marked adult hens and ducklings, respectively. I tested hypotheses about duckling survival and (1) hatch date, (2) initial brood size at hatch, (3) duckling size and body condition at hatch, (4) offspring sex, (5) maternal female size and body condition at hatch, and (6) weather conditions within one week of hatching. Most mortality occurred during the first six days of duckling age. Variation in both duckling and brood survival were best modeled with effects of hatch date and initial brood size, while effects of female condition, female size, duckling size, and duckling condition were inconsistent. Survival probability clearly decreased with advancing hatch date and increased with larger initial brood sizes. Effects of weather and offspring sex in 2001, the only year such information was collected, suggested survival was negatively related to poor weather, but sex of ducklings, beyond size-related differences (i.e., sexual-size dimorphism), was unimportant. Estimates of survival to 28 days of age (30-day period), whether for ducklings (0.016, 0.021) or broods (0.084, 0.138) in 2000 or 2001, respectively, are the lowest of published studies and first for scoter broods in North America. I suspect intense gull predation shortly after hatch had the largest influence on duckling survival. Further research is needed to ascertain if low nesting success and duckling survival as well as other life cycle components are limiting scoter populations locally and throughout the rest of their breeding range.
136

Breeding Ecology Of The Egyptian Vulture (neophron Percnopterus) Population In Beypazari

Sen, Bilgecan 01 December 2012 (has links) (PDF)
The aim of this study was to determine the habitat features affecting nest site selection and breeding success of the endangered Egyptian Vultures (Neophron percnopterus) breeding around the town of Beypazari. We searched and monitored nest sites in the study area (750 km2) for the years 2010 and 2011. The differences in terms of habitat features between nest sites and random points distributed along cliffs, and between successful and failed nest sites were investigated using both parametric approaches and machine learning methods with 21 habitat variables. The size of the Beypazari population of Egyptian Vultures was estimated to be 45 pairs. Seventeen nests in 2010 and 37 nests in 2011 were found and monitored. The breeding success of the population was estimated to be 100% in 2010 and 70% in 2011. Random Forests was the modeling technique with the highest accuracy and the modeling process chose 6 and 4 variables affecting nest site selection and breeding success of the species, respectively. Results showed that human impact was a potential factor governing the distribution of nest sites in the area and increased the probability of breeding failure as vultures clearly preferred to nest away from nearby villages, towns and roads, and nests on lower cliffs and nests that are close to the dump site (therefore the town center) was prone to failure. Utilization of elevation gradient and aspect showed trends similar to other populations of the species, with probability of nesting increasing at lower altitudes and for south facing cliffs. The overall results emphasize the potential conflict between human presence and the population of Egyptian Vultures in the area. Continuous monitoring of the nest sites and conservation activities towards raising public awareness are advised.
137

Breeding Success And Reproductive Behavior In A White Stork ( Ciconia Ciconia) Colony In Ankara

Gocek, Cagri 01 September 2006 (has links) (PDF)
White Stork ( Ciconia ciconia, Linnaeus, 1758) is a summer visitor and passage migrant in Turkey. Although being widespread in summer near wetlands of Turkey, except for the eastern and western parts of the Black Sea Region, there has been no research on this species involving regular monitoring of nests. In this study, breeding success and survival of nestlings in a population in Kizilcahamam-Ankara as well as behavioral differences among nests and their probable consequences on breeding success were studied. Regular field observations throughout six-month long breeding seasons between 2003 and 2006 were carried out to determine parent and young behavior patterns at nest. Clutch size, and numbers of chicks hatched and fledged fluctuated throughout 2003-2006 for pairs that bred while fledgling success (average fledgling per successful nests with egg laid) were 2.63 in 2003, 3.82 in 2004, 1.89 in 2005 and 3.13 in 2006. These values are in good agreement with those recorded in northern Europe. The relationship between beginning date of incubation and both clutch size and brood size were found to be different for 2004 and 2005. Such a relationship may be significant in breeding seasons colder than usual. For 2004 and 2005, the amount of food brought and caring towards young by parents were compared with breeding success (proportion of hatched young that were fledged), and breeding success was found to increase with increasing amount of food provisioning. However, this result may be suggested to be related with weather conditions. In conclusion, Kizilcahamam White Stork population has been found to be not restricted by food or nest site availability and with a reproductive output above the European average, although annual climatic stochasticity was found to affect reproductive output.
138

Population Dynamics of Northern Bobwhites in Southern Texas

Demaso, Stephen 16 January 2010 (has links)
Northern bobwhites (Colinus virginianus) are an important cultural, ecological, and economical part of the southern Texas landscape. I used radio-telemetry data from 2000?2005, part of a long-term, bobwhite study in southern Texas, to test the nest-concealment hypothesis, develop a stochastic simulation model for bobwhite populations, and evaluate the influence of brush canopy coverage (BCC) on short- and long-term demographic performance of bobwhites. Bobwhite nests tend to be situated in taller and denser vegetation than would be expected if nest-site location was a random process. I compared 4 microhabitat variables between successful (n = 135) and depredated nests (n = 118). I documented similar microhabitat attributes between successful and depredated nests. The discriminant function correctly classified only 48?59% of nest fates into the correct group, but only 18% of the variation in nest fate. Thus, my results did not support the nest-concealment hypothesis. My stochastic simulation model for bobwhite populations is based on difference equations (?t = 3 months) and simulations run for 100 years using STELLA� 9.0.2. The probability of persistence for 100 years for the spring population was 74.2% and 72.5% for the fall population. Simulated population parameters were similar to those observed in the field for 5 of 6 population parameters. Only simulated male adult annual survival differed by 275.0% from field estimates. Despite this difference, my model appears to be a good predictor of bobwhite populations in the Rio Grande Plains of Texas. I estimated bobwhite density, survival, and production (proportion of hens nesting, nesting attempts per hen, and clutch size) in 3 study areas with ~10%, ~25%, and >30% BBC. All demographic parameters were similar among the 3 BCC classes. However, simulation modeling indicated that long-term demographic performance was greater on the ~25% and >30% BCC classes. The probability of fall population persistence was greater in the ~25% (90.8%) and >30% (100.0%) BCC classes than in the ~10% BCC class (54.2%). My study highlights the shortcoming of considering only short-term effects when comparing habitat given that short- and long-term effects of habitat on demographic performance can differ.
139

Evolutionary and conservation implications of sex determination and hatchling depredation in Kemp's ridley sea turtles /

Eich, Anne Marie LeBlanc. January 2009 (has links) (PDF)
Thesis (Ph. D.)--University of Alabama at Birmingham, 2009. / Title from PDF title page (viewed Feb. 1, 2010). Additional advisors: Ken Marion, David C. Rostal, Robert W. Thacker, Jeanette Wyneken. Electronic data (1 file : 10.93 mb). Includes bibliographical references (p. 13-18).
140

Nesting behavior in a reintroduced population of California condors

Sandhaus, Estelle A. 14 January 2013 (has links)
Studies in numerous animal taxa demonstrate that early rearing experience has a profound influence on the development of later adaptive behavior. This has implications for endangered species management, particularly when animals are reared in captivity for reintroduction or in cases in which species managers play an active role in managing animals at the individual or population levels. The California condor (Gymnogyps californianus) is a critically endangered New World vulture that was subject to a period of extinction in the wild followed by ongoing reintroduction in portions of its native range. Though the reintroduced population in southern California is largely adapting well, several obstacles to viability remain that are primarily anthropogenic in nature. The purpose of this study was to quantitatively assess nesting behavior of free-flying California condors in the southern California population to determine whether differences in parental care and nestling behavior are attributable to parental rearing conditions and experience. Hierarchical generalized linear modeling was used to analyze parent and chick activity budget data. Differences among condors were not detected in attendance patterns across either the egg or chick phases of nesting. Variation was not detected among chicks in proportion of time spent active and inactive during the early nestling phase. Variations among older nestlings in the proportion of time spent inactive were observed, with associations detected between inactivity, pair, visibility and season. The proportion of time that parents interacted with nestlings varied from nest to nest, with associations detected between interaction, visibility and season. Finally, potential pair-level variation in the propensity to bring microtrash to the nest was observed. It is concluded that while visibility is often overlooked in behavioral analyses, it is methodologically important to account for this variable in analyses of condor nestling behavior. Further, while some pair-level variation in allocation of care to nestlings is apparent, this appears to be a function of factors not related to individual developmental differences.

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