• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 315
  • 231
  • 127
  • 37
  • 24
  • 16
  • 15
  • 15
  • 15
  • 14
  • 14
  • 14
  • 12
  • 12
  • 12
  • Tagged with
  • 820
  • 180
  • 175
  • 168
  • 163
  • 116
  • 109
  • 107
  • 103
  • 77
  • 67
  • 64
  • 62
  • 57
  • 53
  • 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.
11

Diet overlap and habitat segregation between redbreast sunfish and age-o smallmouth bass in the North Anna River, Virginia

Pert, Edmund J. January 1997 (has links)
I assessed the potential for competition between redbreast sunfish and age-0 smallmouth bass in a regulated Virginia River. I sampled stomachs of sunfish and bass throughout spring and summer. Sunfish were divided into small, medium, and large size-classes. Diets of bass shifted from predominantly Chironomidae (Insecta: Diptera) in June to Baetidae (Insecta: Ephemeroptera) in July and August. Fish also became increasingly important diet components of bass when assessed volumetrically. Small and medium sunfish ate predominantly Chironomidae in all sampling periods. Large sunfish ate mostly terrestrial-based invertebrates, Chironomidae, and Baetidae. Diet overlap of bass with small and medium sunfish was high in June. Bass diets differed from all sunfish in July. In August, high overlap occurred between bass and large sunfish because of their common consumption of Baetidae. Food acquisition was not a serious problem for either species during the summer. Empty stomachs were rare, and total volume of diet items in stomachs remained fairly consistent. Densities of aquatic-based food resources measured in pools and riffle/run habitats fluctuated, but were never scarce. Bass and sunfish foraging behaviors were different, particularly in late summer. Microhabitat used by bass and sunfish was assessed by snorkeling and measuring eight variables in early and late summer. Multivariate analyses revealed that distance from shore was the most important habitat variable separating these species. Bass were found farther from shore than sunfish. In late summer large sunfish were also located far from shore, but bass were associated with bedrock and boulders while large sunfish were associated with silt and sand. Manipulative enclosure/exclosure experiments revealed that the most important mechanism responsible for habitat use and foraging patterns of bass and sunfish was habitat-specific foraging success (pool vs. riffle/run habitats). Bass foraged at least four times more effectively in riffle/run habitat while sunfish foraged about twice as effectively in pools. Sunfish did not depress the food resources in pools enough to reduce the amount of prey consumed by bass. Competition (both exploitative and interference) was much less important in determining diet and habitat use of bass and sunfish than the distribution of food resources. / Ph. D.
12

Privatization of public university housing: a comparative cost analysis of alternative models for student housing in the Commonwealth of Kentucky

Yeatts, George Dewey 10 November 2005 (has links)
The conceptual and methodological issues of public university student housing were examined. Specific issues dealt with providing affordable student housing. The study performed a comparative cost analysis of the various student housing models currently available to public Kentucky universities. Cost data were analyzed for the development and comparison of the baseline study project and three student housing models. Project development costs were analyzed to determine the development costs per square foot of student housing, the construction costs per square foot, the cost per resident or bed, and the cost to develop each bedroom or unit. The study compared the affordability of each project by analyzing the net gains (or losses) of each model. Proforma analysis of cash flows were developed for each model and the baseline for comparison purposes. Such analysis considered typical revenues based on average rental rates and current building operating expenses. Debt coverage ratios for each project were calculated and compared to financial industry standards. Currently many colleges and universities are privatizing their studen~ housing. Although the majority of the educational institutions appear to be very successful with their efforts, institutions are not fully aware of the benefits, pitfalls, or processes involved in the privatization of student housing. There are a number of issues that must be addressed prior to obligating a public educational institution to a long-term leasing agreement with a private firm. This research discussed the financial issues pertaining to the development costs of various student housing models. From this study, conclusions regarding the most cost effective development of student housing facilities were stated. The examination provided for the identification of issues necessary to assess the financial performance of the various student housing models. The discussion of such issues may contribute. to more effective student housing decisions by higher education administrators. Implementation of the most cost effective model may provide a means for economically meeting their university's student housing needs. / Ed. D.
13

The effects of coal mining on sedimentation and fish assemblages in the Powell River, Virginia

Temple, Alan J. 11 July 2007 (has links)
An ecological study was undertaken on the Powell River system in Virginia from 1988 - 1990 to evaluate the effects of land uses on hydrology, water quality, sedimentation (particle size < 2 mm), and fish assemblages and to derive ecological indicators for monitoring. The hydrologic (disturbance) regime of the sixth order reach was Classified. Although surface coal mining appears to have reduced flow variance, the changes were not sufficient to alter the hydrologic classification. Tributaries draining coal-mined lands had elevated specific conductivity, iron, manganese, sulphate, and turbidity relative to tributaries in unmined watersheds or in the sixth order mainstem (p ≤ 0.05). The fifth order reach, which had a greater proportion of watershed area surface-mined, exhibited higher specific conductivity, iron, sulphate, turbidity, and total solids than the sixth order (p ≤ 0.05). Despite the upstream-to-downstream, lower-to-higher water quality gradient, there was no compelling evidence from the use of state water quality standards and a nine-variable water quality index that water quality differentially affected fish assemblages. The primary physical habitat gradient in the lower river was sedimentation. Upstream, embeddedness increased in shallow-water habitats (p ≤ 0.001) and sediment depth increased in pools (p ≤ 0.001). Stepwise multiple regression analysis indicated that variation in sediment level was explained primarily by the proportion of the watershed surface-mined (R² = 0.75). Index of Biotic Integrity scores for fish assemblages were not correlated with sedimentation in shallow-water or in pool habitats (p > 0.066). Functional metrics, as opposed to taxonomic metrics, however, varied with sedimentation (p ≤ 0.002). In shallow-water habitats, omnivore relative abundance increased and specialized insectivore abundance decreased in higher sedimented sites. Top carnivore abundance decreased in pools with higher sedimentation levels. Abundance of lithophilous benthic spawners, postulated as the most sediment-sensitive reproductive guild, was not consistently correlated with sedimentation. Nine fish species were classified as sediment-intolerant and eight were classified as sediment-tolerant. The sediment-intolerant group was composed mostly of benthic insectivores. Habitat analyses indicated that sediment-intolerant species, as a category, utilized microhabitats with low sedimentation levels relative to the sediment-tolerant species group (p ≤ 0.0001). Species not classified as either sediment-intolerant or sediment-tolerant utilized microhabitats intermediate in sedimentation level (p ≤ 0.0001). / Ph. D.
14

Midlife development and disability onset in a family context: a qualitative integration

Wingfield, Nancy Poe 03 October 2007 (has links)
Much research on disability has focused on individuals with congenital anomalies and birth defects, and has emphasized the medical aspects of various impairments. Investigations have centered on the treatment and management of problematic physical symptoms with little attention given to the meaning of disabilities for people's family and social relationships. The literature fails to reflect a recognition that most disabling conditions occur later in life as a result of injury or illness and are inadequately defined or described in singularly negative terms. This study was undertaken to examine how adult-onset disability is experienced in various social contexts, and to consider how individuals who become disabled in adulthood and their family members develop an understanding of what disability means, beyond consideration of medical care and physical treatment. Qualitative data were collected from a purposive sample of 9 intimate couples in which one of the partners had been diagnosed with multiple sclerosis. Indepth conjoint interviews were conducted with each couple, followed by private interviews with the 18 individual partners, rendering different perspectives on disability as a personal and familial experience. The results indicate that disability onset in middle adulthood is an important, but not all-encompassing, experience that shapes the individual lives of those affected and their loved ones, as well as their shared life as a couple. Contrary to much research that frames disability in tenns of stress or deficit models which assume negative and problematic experience, the results of this investigation indicated that disability is perceived as having some positive aspects on personal and family development. The data indicated that disability is a process that takes place over time and through which people's perceptions and experiences are altered, as opposed to a being a permanent identity or status that occurs as a result of a discrete event. / Ph. D.
15

Effects of emotional state and food novelty on preschool children's acceptance of food

Slank, Kristine Lynn 10 November 2005 (has links)
Humans and other animals typically consume less of novel foods than of familiar ones, a phenomenon termed ingestional neophobia. Young children display especially high levels of neophobia, spitting out new foods but accepting those same foods after familiarization. Rejection of novel foods presumably reflects the aversiveness of the food's novel sensory cues, which thereby occasions withdrawal. Familiar foods typically evoke acceptance, suggesting that familiar foods are not categorically aversive. According to a biphasic model of emotion, negative affective behaviors (e.g., withdrawal) are enhanced during negative emotional states and inhibited during positive states. Positive affective behaviors (e.g., approach, consumption) are enhanced during positive emotional states but inhibited during negative states. If neophobia (withdrawal) and food acceptance (approach) reflect negative and positive affective behaviors respectively, according to the biphasic model, emotional state at the moment of food presentation should mediate the display of neophobia and food acceptance. To induce mood, preschool children were asked to think of things that make them happy (positive), sad (negative) or asked to count (neutral). Following mood-induction (MI), children received a familiar- or novel-appearing food. Acceptance was assessed as latency to touch the food, latency to Bite 1, latency to Bites 2-5, amount eaten, rate of eating, and degree of food contact. Acceptance was expected to be greater for the familiar- than for the novel-appearing food, and greater in the positive MI than in the neutral MI than in the negative MI condition. An interaction between food appearance and MI condition was expected. Results indicated that children who received a novel-appearing food ate reliably less and reliably slower than children who received the same food in its familiar appearance. There were no effects of MI condition. However manipulation checks indicated that MI procedures were ineffective. Participants were therefore reassigned to mood groups based on ratings of expressed affect. Analysis of reassigned groups indicated that the negative mood group took significantly longer to touch the food, to Bite 1, and to Bites 2-5 than did neutral and positive groups. The negative mood group ate reliably less than the neutral group, who ate reliably less than the positive group. / Ph. D.
16

Networks and professionalization: a history of the Virginia Academy of Science, 1923-1995

Webb, Charlotte 27 February 2007 (has links)
In 1923, scientists and science educators gathered in Williamsburg at the College of William and Mary for the first meeting of the Virginia Academy of Science. Representing a variety of scientific disciplines and heralding from virtually every institution of higher education in the Commonwealth, the 135 charter members eagerly supported the establishment of an association to facilitate professional development. Virginia scientists were not unique in chartering an academy to promote professionalism. Over the past century and a half in the United States, organizations at the national and state levels played critical roles in professional advancement. Offering camaraderie, encouraging research, and in some cases, providing a publication outlet, scientific organizations often function as the nucleuses of professionally supportive scientific networks. This dissertation traces the development of the Virginia Academy of Science from 1923 to 1995. Looking discriminately at the past, this study emphasizes the sociology, economics, and politics of the Virginia Academy as well as the Academy's interaction with the larger Virginia society. In so doing, the dissertation examines both Academy's more obvious role in shaping the ideas and institutions of science in twentieth-century Virginia and its less-recognized impacts on individuals and ideology. Incorporating recent perspectives from the disciplines of science and technology studies, this dissertation reveals how the Virginia Academy of Science molded and in tum was molded by the complex. of contemporary practices, interactions, and beliefs on state and national levels. In other words, the analysis considers the ways in which the Academy has been and still is both reflective of and a shaping influence on Virginia culture. / Ph. D.
17

Behavioral scripts of urban park offenders: a rational choice perspective on influences of the park setting

Michael, Sean Edward 08 November 2006 (has links)
This study examined the influence of Iocational factors on offender behavior in four serious and common park offenses: auto burglary, drug sales, indecent exposure by homosexual males, and robbery. Specifically, the study sought 1) to develop prototypical script(s) for each of the four study crimes, and 2) to support or contradict the influence of effort, risk and reward on offender behavior. Using the theoretical bases of opportunity, rational choice, and scripts, behavior of study offenders in 6 U.S. Park Service reservations in Washington, DC was interpreted. A case study strategy was chosen, utilizing participant observation, direct observation, archival records, physical artifacts, and interviews. Data collection occurred between January and March, 1996, with law enforcement personnel serving as the primary information source. Following qualitative analysis that relied upon pattern-matching and explanation-building, results suggested that 1) offenders follow logical sequences of behavior consistent with concept of a script, 2) offenders were found to act rationally, appearing to consider effort, risk and reward, 3) that offenders weight the importance of effort, risk and reward differently across offense types and across the different Acts of the same offense script, 4) that Iocational factors do influence the behavior of offenders, and 5) that offenders utilize Iocational factors that serve to decrease effort and risk, and increase reward. / Ph. D.
18

A case study of a primary school using the action research process to study parental involvement practices

Reynolds-Johnson, Yvonne O. 05 October 2007 (has links)
This study was designed to examine team interaction as a team utilized the action research process. The research questions that were investigated in this study are: 1. How do working relationships evolve in action research teams? 2. What is the role of the principal as facilitator? 3. What do team members perceive as the advantages and disadvantages of the action research process? This study specifically investigated the interactive roles of an action research team composed of parents, teachers and the administrator as they used the action research process to study parental involvement. The research project was designed as a case study of one school. Qualitative data were collected from tape recordings of meetings, journal records, interviews, and questionnaires. Quantitative data were secured from a survey completed by team participants on team effectiveness. This study provides additional research on how a team consisting of parents, teachers and a principal interacted and worked to solve a problem. The study showed the development of the capacity of a team to solve a problem using the action research process. The primary significance of this study was to learn how action research might be used as an approach to develop and implement strategies to enhance the involvement of parents in their child's education. Utilizing the action research model in Crewe Primary school allowed team members (parents and teachers) the opportunity to learn this approach and apply it to other areas requiring improvements. This study will also provide a model for other schools interested in utilizing action research. / Ed. D.
19

A typology of community college students and the development of profiles of associated student types

Massey, Albert Johnnie 03 August 2007 (has links)
This dissertation proposes a typology of community college students that includes traditional college students and seven types of nontraditional students. Since the 1960s the number and types of nontraditional students has increased as a broader portion of the American population seeks higher education. Based on the literature of the past twenty-five years, a typology of eight students types was developed and tested for existence. Using both qualitative and quantitative research methods, profiles of each student type was developed. The profiles were tested for differences among the eight types. Of the student population in the campus studied, only 1% were traditional college students. The remaining students were clustered into three primary and four secondary types. Differences among the primary types were observed across six categories of defining characteristics. The primary groups included first-generation adult students who were unprepared for college, unprepared "New" students who were not first-generation students, and nontraditional adult students who were not first-generation students. Contrary to previous studies of nontraditional students, students in this study reported support for their education efforts from their family, friends and employers. The study concludes with a suggested three-dimensional community college function model that provides a means to consider the "fit" or congruence between the function model in place at a community college and profile of the students the college attracts. / Ed. D.
20

Action at a distance for specific repression of the glpD and glpTQ genes, and organization of the glpEGR genes of Escherichia coli K-12

Yang, Bing 04 October 2006 (has links)
Aerobic sn-glycero13-phosphate (glycerol-P) dehydrogenase is a cytoplasmic membrane-associated respiratory enzyme encoded by the g/pD gene of Escherichia coli. The divergently transcribed glpACB and glpTQ operons encode the subunits of the anaerobic glycerol-P dehydrogenase, glycerol-P transporter, and glycerophosphodiesterase, respectively. The glpD operon is controlled by cooperative binding of glp repressor (GlpR) to tandem operators that cover the -10 promoter element and 30 bp downstream of the transcription start site. The glpACB-glpTQ operons operons are controlled by GlpR binding to operators that overlap the glpA promoter elements. In this study, two additional operators were identified within the glpD structural gene, and three additional operators were identified within the glp T structural gene. / Ph. D.

Page generated in 0.0205 seconds