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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.
81

EVALUATION OF THE DOMESTICATION STATUS OF COW COCKLE (Vaccaria hispanica [P. Mill.] Rauschert) POPULATIONS

2014 July 1900 (has links)
Cow cockle (Vaccaria hispanica [P. Mill.] Rauschert) is a summer annual species introduced to North America from Europe. It has been investigated as a potential crop for the Canadian prairies because of its ultra–fine starch, cyclo–peptides, and saponins. However, cow cockle has a long history of being a weed in Canada and may need additional scrutiny of its weediness potential before initiating commercial production. In addition, cultivating poorly domesticated species may lead to further environmental and weed management risks; hence, an understanding of the domestication status is required. The objectives of this research were to evaluate available cow cockle germplasm i) to identify populations that are best adapted to cultivation as well as the traits responsible for such adaptation, ii) to determine seed dormancy levels in cow cockle populations and to determine how temperature and light affect seed dormancy and germination, and iii) to determine whether cow cockle populations are persistent and form a seed bank. A total of 15 cultivated, weedy, and wild cow cockle populations from different parts of the world were compared for agro–morphological, seed dormancy and seed persistence characters from 2009 to 2011. In the field persistence study, two populations including weedy (Scott weedy) and cultivated (Scott) lines were included. Cluster analysis revealed three main groups among the populations based on the traits studied. Physiological maturity, seed size, plant height and seed yield differed most among populations. The cultivated populations, Pink Beauty, Turkey, PB–87, Scott and a weedy population, UMan–89 had higher seed yield, larger seeds, and greater biomass compared to the other populations. Although weedy populations showed some adaptation to cultivation, characters relating to plant architecture, seed size and yield suggested a weedy habit. Freshly matured seeds of all the populations showed high levels of primary conditional dormancy except “Mongolia”. At optimum temperature conditions for germination (10 C), the effect of temperature regime (alternating and constant) and light on seed dormancy were insignificant. The variation in optimum temperature, light, and their interactions among the cow cockle populations may be due to the plants evolving to adapt to their local environments. In the field persistence study, the weedy population had higher seedling emergence at two out of three locations and a larger residual seed bank at all the locations. Despite the differences in seed persistence between the populations, considerable numbers of seed of both weedy and cultivated lines were recovered from the soil seed bank at the end of the study. This concurs with the results of the laboratory persistence study, as both the populations had greater seed longevity (p50 values > 50 days) which suggests a field persistence of over three years. In conclusion, higher seed yield, larger seeds, and greater biomass in cultivated populations may result from certain pre–adaptation towards domestication, which may have been acquired during the process of pre–domestication cultivation. From a domestication perspective, if cow cockle were grown as a crop, the conditional dormancy may not be considered a barrier to domestication and can be viewed as a physiological mechanism to avoid germination at harvest. The major concern in cow cockle domestication would be seed persistence, as it can form a reasonably long–term seed bank. This may pose some concerns for the production of cow cockle as a crop in the Canadian Prairies. The current research suggests that cow cockle populations from Canada, although they showed some adaptation to cultivation; are largely weedy and can be considered as variants of an early introduced species which might have evolved to adapt to non–native conditions.
82

Stories of Persistence of Undergraduate Nursing Students

Schulz, Briar 30 April 2013 (has links)
Attracting and retaining student nurses who will persist in their academic studies is essential to the success of the Canadian health care system. While a small body of knowledge existed in the area of retention and attrition of undergraduate nursing students, little was known about the students’ perspectives on persistence. Through a qualitative analysis of the stories of persistence for six undergraduate nursing students from the University of Victoria, this study revealed and explored the variety of factors that influence undergraduate student nursing persistence. Important information for improving Canadian nursing education was revealed in the process. Mainstream qualitative research techniques in this study were expanded with the use of photovoice. Photographs taken by the study participants were used to elicit their narratives of persistence, increasing the accessibility of the stories’ emotional content. Internarratives were also derived from aspects of the participants’ original stories and provided an additional approach for understanding student nursing persistence. The results of the study revealed six main themes that represented major factors of influence on student nursing persistence: (a) support, (b) challenges to persistence, (c) motivation to continue persisting, (d) the nursing profession, (e) teaching, and (f) the curriculum. The study demonstrated the critical importance of understanding undergraduate nursing persistence from the students’ perspectives, as well as the value of incorporating photovoice as a methodological strategy. The implications for nursing recruitment, education, and future research were also discussed and continued research on and further dialogue about these issues were deemed important for nursing education. / Graduate / 0745 / briarschulz@shaw.ca
83

The evolution of human diversity : a phylogenetic approach

Holden, Clare Janaki January 1999 (has links)
The socio-ecological correlates of cross-cultural variation in lactase persistence, sexual dimorphism in stature, and wealth inheritance in Africa were investigated, using phylogenetic comparative methods to control for the non-independence of populations (Galton's problem). Felsenstein's method of comparative analysis using independent contrasts, and Pagel's phylogenetic maximum likelihood model, were used. Genetic and linguistic trees were used as models of the past relationships among populations. Lactase persistence was found to be associated with pastoralism but not with solar intensity or aridity. This is consistent with the hypothesis that high lactose digestion capacity in adults is an adaptation to dairying. This result does not support the hypotheses that low solar radiation at high latitudes and aridity are additional selective pressures for lactase persistence. Cross-cultural variation in stature was associated with women's work. Women are taller, relative to men, in societies where women contribute more to subsistence. In Africa, patrilineal wealth inheritance is associated with pastoralism and polygyny. Patrilineal wealth inheritance is adaptive if inherited wealth benefits sons more than daughters, which is probably the case in both polygynous and pastoralist societies. It is hypothesised that matrilineal inheritance arises from wealth inheritance to daughters. Inheritance to daughters is adaptive if the additional benefits of wealth inheritance to sons do not outweigh the risk of paternity uncertainty of sons' offspring. The transmission, between populations, of those bio-cultural traits in the comparative analyses was also investigated. The association between each trait in a population, and that trait in the population's phylogenetic sister-group and nearest geographical neighbour(s) were compared using regression. The majority of traits were found to be associated with phylogeny. Some traits showed an additional association with geographical neighbours. Vertical transmission, from `mother' to `daughter' populations, appears to be more important than geographical diffusion between neighbouring populations, for the majority of the traits tested here.
84

Community college student persistence : a field application of the tinto model /

García, Mildred. January 1987 (has links)
Thesis (Ed. D.)--Teachers College, Columbia University, 1987. / Typescript; issued also on microfilm. Sponsor: Robert Birnbaum. Dissertation Committee: Richard Anderson. Bibliography: leaves 138-146.
85

Mothers of invention : developing a better understanding of mothers' doctoral persistence /

Underwood, Siobhan. January 2002 (has links)
Thesis (Ph. D.)--University of Oregon, 2002. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 167-176). Also available for download via the World Wide Web; free to University of Oregon users.
86

Conversations with under-prepared university students : a case study with implications /

Cowles, Carol Ann, January 2004 (has links)
Thesis (Ed. D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 74-77). Also available on the Internet.
87

Conversations with under-prepared university students a case study with implications /

Cowles, Carol Ann, January 2004 (has links)
Thesis (Ed. D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 74-77). Also available on the Internet.
88

Factors Influencing Career Choice Among Students Enrolled in a Four-Year Tourism Administration Program

Davis, Nicole Lynn 01 January 2009 (has links)
The tourism industry is often viewed as an industry in which one would not want to be employed. This negative stigma is cause for concern when youth are beginning to make career decisions. The purpose of this study was to examine student perceptions of the tourism industry, factors that influence them to pursue a tourism career path, and their participation in a tourism-related education program. Little research exists regarding tourism career development and degree program persistence, and available literature is largely quantitative in nature. A follow-up explanatory sequential mixed methods design was used in this study. Surveys were distributed to students enrolled in tourism-related programs at six American universities; data were analyzed using descriptive and inferential statistics. Based on findings, four focus groups were held at one university. Results suggested that while students had positive perceptions about the tourism industry, it was not typically their first career choice. Industry experience and specific job characteristics were highly influential on the career decision process. Five themes emerged from the qualitative data analysis; common factors that influence career choice, lack of awareness of tourism-related degree programs, relevance of experience and internships, common areas of program satisfaction, and suggested improvements programs. The implications of this study for educators, industry leaders, and parents are many. Recognizing factors that influence a student to enter a tourism-related career help educators pinpoint where and, to an extent, how to disseminate information about the tourism industry and related educational programs. This information may also be useful for industry leaders as they seek to obtain trained employees, whereas they can determine outlets at which to create awareness of this industry.
89

Perceptions of Persistence: Why Community College Students are not Persisting

Maue, Lea 01 May 2012 (has links)
The purpose of this study was to illuminate the barriers to persistence underprepared students at the community college experience after the initial successful completion of one semester. A qualitative interview study, grounded in phenomenology, was implemented. Participants were identified through a process of purposeful selection, which included the following criteria: (a) beginning the development reading sequence at the most basic level (DEV 65) and passing that course; (b) immediately enrolling in a subsequent semester at the institution; and (c) exiting the institution before acquiring any credit-bearing English coursework. The examination of institutional archival data resulted in 42 potential participants. Participants were recruited via telephone and mail, and of the 42 attempted telephone and 39 mailed contacts, five individuals volunteered to participate in the study. Each participant was interviewed individually, with sessions varying in length between 51 and 119 minutes. Immediately after each interview was complete, the audio recording was listened to in its entirety and transcribed verbatim. The resulting transcripts were analyzed through a modified version of Devinish's (2002) applied method for phenomenological explication of interview transcripts. This involved a multi-layered process of recursive analysis beginning with line-by-line open coding, extracting 333 natural meaning units (NMU). In a second stage of analysis, the NMU were further sorted, analyzed, and grouped to arrive at 46 central themes. The third stage of analysis involved collating and grouping central themes into related fields employing a concept map to form at 13 interpretive themes. The final stage of analysis included a further examination of the 13 interpretive themes, where each was rank ordered by importance (frequency x intensity = priority) and then synthesized with data from lesser themes, which resulted in the following six explicative themes: (a) significant environmental stressors; (b) a sense of self-sufficiency and independency; (c) reading problems; (d) a belief in the power of perseverance; (e) instructor characteristics; and (f) financial aid restrictions. These six explicative themes captured the essence of what it meant for the participants to be an underprepared student at the college and identified the perceived barriers to persistence.
90

Which relationships matter? Communicating college persistence in the rural non-rural student divide

Stefka, Cassidy January 1900 (has links)
Master of Arts / Department of Communications Studies / Natalie Pennington / College student persistence has long interested scholars and universities alike (Bean, 1983; Goodman, & Pascarella, 2006; Hlinka, 2017; Moschetti & Hudley, 2014; Pascarella & Terenzini, 2005; Tinto; 1993; 2012). While universities have given attention to the academic integration of students (e.g., their GPA and general academic performance), social integration has become increasingly more studied as an integral component to a student’s likelihood to persist (Tinto, 1993; 2012). This study incorporated social capital theory (Coleman, 1988) as a lens to understand how social integration may affect a student’s likelihood to persist. Using survey methodology and a sample of first-year students at large midwestern university (n = 101), the results showed that strong school social capital in the form of relationships with peers and authority figures at college may help a student overcome structural disadvantages embedded within their family and home community social networks. Specific differences in the formation of social capital between nonrural and rural students were also explored with meaningful results. Rural students were more likely to perceive stronger relationships with authority figures at college than nonrural students, and nonrural students were more likely to perceive their home communities as more supportive of higher education than rural students.

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