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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.
171

THE ROLE OF FOMITES IN THE TRANSMISSION OF NOROVIRUS

Fankem Mingo, Sonia Laure January 2008 (has links)
Introduction: Acute gastroenteritis is a common illness in humans. It has a high morbidity worldwide and in the United States (U.S); a sizeable mortality is reported in developing countries. Viruses are a common cause of acute gastroenteritis and noroviruses are the leading cause of non-bacterial gastroenteritis (1). Fomites play an important role in the infection cycle of norovirus. This study explored the comparability between a quantitative microbial risk assessment (QMRA) model to predict the probability of illness from norovirus due to environmental contamination with actual observed attack rates, the impact of appropriate cleaning procedures on fomites contamination, and the role of fomites in the transmission of norovirusMethod: Data from three different norovirus illness outbreaks occurring from 2004 to 2005 in Arizona in different venues were used. Questionnaires were used to determine demographics, symptoms associated with gastrointestinal illness, medical visits, and potential exposures such as food items consumed. When available, stool samples were collected from ill participants. Fomites samples were also gathered from the different venues; houseboats, college summer camp living spaces, and a restaurant. These samples were tested for norovirus using reverse transcriptase polymerase chain reaction (RT-PCR). Viral concentration on fomites was calculated using the most probable number methodology.Results: Norovirus was found on fomites from all three outbreaks. Improper cleaning of fomites increased the proportion of norovirus positive fomites from 40 percent to 70 percent in contrast, after cleaning and disinfection with 5000 mg/L free chloride, the proportion of norovirus positive fomites decreased to 33%. The predicted values from the quantitative microbial risk assessment model were consistent with the observed epidemiological attack rates.Conclusion: This study showed unequivocally that fomites play an important role in the transmission cycle of norovirus, and that improper cleaning and disinfection procedures only serve to spread the virus to previously uncontaminated fomites. In the case of outbreaks where people are not always available to answer questionnaires, QMRA should be considered as a worthwhile alternative to a full-scale epidemiological study.
172

Ethnic group affiliation and social exclusion in Cornwall : analysis, adjustment and extension of the 2001 England and Wales Census data

Husk, Kerryn Michael January 2012 (has links)
This thesis provides a critical understanding of the size and relative position of the Cornish in Cornwall, a county in the south-west of the UK. Cornwall is a region which has experienced increased levels of disadvantage for a prolonged period of time. The indigenous people, whilst seeing a rise in their inclusion in ethnicity variables in the region, have remained under-researched in terms of their socio-economic position relative to the non-Cornish in the same geographic area. This thesis addresses this gap in the literature and represents the first in-depth examination of the group. The 2001 Census included an option to ‘write-in’ a Cornish ethnic identity, however whilst accurate in the responses it recorded the result was almost certainly an under-enumeration due to the lack of a dedicated tick-box selection. This thesis is a rigorous examination of the Cornish, starting with these data, estimating their size and socio-economic position (in terms of social exclusion) relative to non-Cornish individuals. Three stages of primary analysis sought to; analyse, adjust and extend the 2001 Census result to broadly estimate the size, links with exclusion and the causal processes behind these links. Firstly, an accurate picture of the size of the Cornish population was estimated using an innovative weighting strategy, developed to collate all other data referring to the Cornish and to derive weights for application to the raw Census data. Secondly, a stage of primary survey research examined this group more directly for links with social exclusion factors; and thirdly, a stage of qualitative interviews with knowledgeable individuals in the region lent depth to the findings and provided a more coherent explanatory framework. The results indicate that the Cornish are certainly more numerous than the 2001 Census had indicated. The proportion of individuals self-identifying as Cornish is likely to be closer to a quarter of the population rather than the 6.7% indicated in the 2001 ii data. There was some discrepancy in the data between the belief amongst the group of social exclusion and the reality. In order to explain the discrepancy, a model was used which explores the difference between personal-level experience and group level discrimination (Taylor et al 1990). The results of this thesis highlight the complex and multi-dimensional processes inherent in, firstly, the methodological and practical process of ethnicity measurement and, secondly, its use as an explanatory variable for social exclusion experience. Overall, this thesis represents the first and most comprehensive examination of the indigenous people of Cornwall and their relative lived experience compared to non-Cornish in the same area.
173

Actual and desired factors of effective organisation and management of teaching and learning practices : a case study amongst lecturers and middle-leaders at a higher education institution in Oman

Thomas, Andrew George January 2009 (has links)
This thesis explores the degree to which perceptions of lecturers and middle-leaders about the actual and desired organisational characteristics of a Higher Education Institution in Oman converge and/ or diverge with regard to the effective operation of teaching and learning processes within the institution. Using a card sort of 32 criteria derived from 16 factors of effectiveness drawn from the literature, it analyses the data quantitatively to arrive at participants’ perceptions of the factors currently operating in the organisation and those desired for the future, and therefore which factors enable or hinder operational processes. Findings show that at the characteristic level, divergence is significantly greater between lecturers and middle-leaders, irrespective of faculty, than between lecturers from different faculties, or middle-leaders from different faculties. Current lecturer perceptions of organisational effectiveness/ ineffectiveness converge most strongly on factors of Collaboration and Professional Development. Middle-leader perceptions of current organisational effectiveness/ ineffectiveness converge most strongly on factors of Expectations of Success, Accountability, Professional Development, Environment, and Focus. At the more-desired/ less-desired level convergence is strongest between lecturers and middle-leaders on the factors of Expectations of Success, Collaboration and Professional Development. The study concludes that at the current level, there is a gulf between lecturers and middle-leaders that needs to be bridged if the organisation is to effectively organise the management of teaching and learning practices. The findings extend effectiveness into Higher Education in Oman and support the use of factors of effectiveness in educational research. Findings also demonstrate the usefulness of focus groups, card sorts and a quantitative analysis of data as starting points for organisational self-evaluation and review. Recommendations encompass further research as to how organisational members conceptualise and measure ‘success’, ‘collaboration’ and ‘development’; and investigation of other stakeholder perceptions of effectiveness.
174

Religion and Recruitment : A quantitative study on the effects of religious motivations for conflict on rebel recruitment.

Knutas, Frida January 2017 (has links)
No description available.
175

What are the minimum requirements of numbers used in a good case study?

Lezis Israelsson, Jennifer January 2016 (has links)
No description available.
176

Construct Validity Evidence Based on Internal Structure: Exploring and Comparing the Use of Rasch Measurement Modeling and Factor Analysis with a Measure of Student Motivation

Coleman, Mary Angela 01 January 2006 (has links)
The current study examined and compared the use of Rasch measurement, common factor analysis (EFA), and confirmatory factor analysis (CFA) in establishing construct validity evidence based on internal structure with multi-item scales measuring middle and secondary students' achievement goal orientation and academic self-efficacy. 1054 complete responses were received to 18 items measuring mastery, performance-approach, performance-avoidance, and self-efficacy. Items in each subscale were first analyzed by each method as a unidimensional unit. Items were then analyzed by each method as a multidimensional unit. Results showed that when scales were analyzed individually, all three methods corroborated unidimensionality; however, when all items were analyzed together, the multi-factor model identified through EFA was not supported by the Rasch or CFA analysis. While EFA provided the best information about individual item functioning, Rasch provided important, additional information about rating scale functioning and item fit that helps diagnose poorly performing items. Results also support the use of EFA in evaluating the suitability of a scale for meeting the unidimensionality requirement of item response models. While the mastery and efficacy scales performed in a manner consistent with the motivation literature, the approach and avoidance subscales did not. Conclusions from the study include the need for better explication of conjoint use of classical and modern test theory methods in instrument development, more exposure of current and future researchers to the foundations of measurement theory, and more research about the saliency of measuring performance-avoidance.
177

L'obéissance à l'autorité : une étude comparative d'après le modèle des recherches expérimentales de Stanley Milgram

Barrette, Pascal January 2005 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
178

The role of internal stakeholders and influencing factors during the phases of e-government initiative implementation

Al-Rashidi, Hajed January 2013 (has links)
Governments around the globe were actively implementing e-government initiatives in the past two decades. However, the majority of e-government initiatives fail in achieving their objectives before, during or after implementation. This study is addressing the problem, e-government initiatives are still more failure than success. Literature indicates differing models that analyse various stages, stakeholders and factors influencing e-government implementation in the public sector. Yet, these models do not explore in particular the important roles and responsibilities of internal stakeholders and influencing factors during different phases of the implementation cycle of the e-government initiative. There is a need for a framework that guides the e-government initiative implementation internally. To achieve the aim of this research, this study should empirically investigate "managing e-government initiative implementation." Consequently, this thesis results in research that contributes towards successful e-government initiative implementation based on empirical data derived from three case studies. The practical parts of the research are three case studies on e-government initiative implementation, which are analysed using an interpretive and qualitative research approach. Besides document analysis and observation, interview was the main method to collect empirical data for this study. For an accurate result, only managers and above level are selected and interviewed. The study examines the proposed framework in three government organizations in the State of Kuwait by using a qualitative, interpretive, multiple case study research strategy. As a result, this thesis is proposing a framework that can be used to enhance the implementation process of e-government initiative throughout the different phases of the implementation cycle, and contributes to the body of knowledge by extending the literature. The stakeholders, factors and implementation phases are mapped together to ease understanding the implementation process of e-government initiative implementation across the public organizations. The study concludes by identifying internal stakeholders, factors, and providing a holistic framework for e-government initiative implementation. The findings of this research are useful for internal stakeholders in the field, as it enables them to gain a better understanding of their own roles and responsibilities. Moreover, researchers in similar fields may find this work useful as a way to approach the study of e-government initiative implementation.
179

LOH- und Expressionsanalysen zur Identifikation neuer prognostischer Marker in Wilms Tumoren / LOH and expression analyses for the identification of new prognostic markers in Wilms tumors

Wittmann, Stefanie January 2007 (has links) (PDF)
Der Wilms Tumor (WT), auch Nephroblastom genannt, zählt zu den im Kindesalter am häufigsten auftretenden malignen Tumoren und entsteht meist unilateral (90 – 95 %) und sporadisch (98 – 99 %). Leider sind bis heute die molekularen Ursachen, die zur Entwicklung dieser Tumoren führen nur unzureichend aufgeklärt. So werden bisher nur drei Gene mit dem Auftreten von WT in Verbindung gebracht: WT1, CTNNB1 und WTx. Während WT1 und CTNNB1 jeweils Mutationsraten von etwa 10 – 15 % aufweisen, die zudem häufig gemeinsam vorliegen, werden für WTx Mutationsraten von etwa 30 % beobachtet. Die genetischen Alterationen der anderen Tumoren sind noch immer komplett unbekannt. Ziel dieser Arbeit war aus diesem Grund die Identifikation von relevanten Regionen und Genen, die an der Entstehung bzw. dem klinischen Fortschreiten von Wilms Tumoren beteiligt sind. Zusätzlich sollten weitere Untersuchungen zur Einschätzung ihres prognostischen Potenzials dienen. In einem ersten Ansatz wurden die Chromosomenbereiche 11q und 16q in einer großen Anzahl von Wilms Tumoren auf LOH (=loss of heterozygosity), d.h. den (partiellen) Verlust von genetischem Material, untersucht. In beiden Fällen wurden erhöhte LOH-Raten von etwa 20 % beobachtet, jedoch war keine Eingrenzung der relevanten Regionen möglich, da Allelverluste nicht stets ab einem bestimmten Marker beobachtet wurden. Ein Vergleich mit der Histologie ergab signifikante Assoziationen der Allelverluste mit anaplastischen und Mischtyp-Tumoren (nur für LOH 11q), wohingegen kaum LOHs in epithelialen und stromareichen Tumoren festgestellt wurden. Somit scheinen auf 11q und 16q Gene vorzuliegen, die einerseits die Differenzierung in Epithel und Stroma begünstigen oder andererseits ein blastemreiches und anaplastisches Erscheinungsbild verhindern. Jedoch könnte auch die Assoziation von bestimmten Subtypen mit LOH 11q und 16q auf eine Entstehung aus unterschiedlichen Zellen hindeuten. Weiterhin war das Auftreten von LOH, v.a. wenn jeweils der komplette Chromosomenarm betroffen war, mit einem erhöhten Rezidiv- und Sterberisiko (nur LOH 11q) verbunden. Somit konnte gezeigt werden, dass LOH-Untersuchungen auf 11q und 16q zur Identifikation von Hochrisikopatienten für die Entwicklung von Rezidiven bzw. erhöhter Mortalität eingesetzt werden können, wodurch eine individuelle Anpassung der Therapiemaßnahmen ermöglicht wird. In einem zweiten Ansatz wurden eine Reihe von bereits publizierten potenziellen Markergenen in einer großen Anzahl von Wilms Tumoren mit Hilfe der Realtime RT-PCR auf ihre Relevanz überprüft. Allen diesen Genen wurde zuvor eine Funktion bei der histologischen Klassifikation der Tumoren bzw. bei der Vorhersage bestimmter klinischer Verläufe zugeschrieben. Die univariate Analyse diente der Beurteilung der Relevanz einzelner Gene, wohingegen die multivariate Analyse zur Bestimmung von prognostischen Genkombinationen eingesetzt wurde. Anschließend erfolgte die Validierung mittels eines zweiten und unabhängigen Tumorsatzes. Auch wenn viele der bereits publizierten Marker und in der ersten Analyse erhaltenen Assoziationen in einem weiteren und unabhängigen Tumorsatz nicht verifizierbar waren, konnten dennoch einige frühere Ergebnisse repliziert und die Relevanz der entsprechenden Gene nachgewiesen werden. Neben der Verbindung der Repression von HEY2 und TRIM22 mit Hochrisikotumoren bzw. einer höheren Sterbewahrscheinlichkeit fanden sich schwach signifikante Assoziationen auch für die verminderte Expression von TRIM22 und VEGF mit der Histologie. Ebenso waren erhöhte Level von TERT und die Repression von TRIM22 mit der Entwicklung eines Rezidivs verbunden. Vor allem aber die Korrelation der Repression von HEY2 und VEGF sowie einer Überexpression von CA9 mit Rezidiven, Tumoren hoher Malignität oder primären Metastasen verweisen auf die Notwendigkeit, besonders die Hypoxie- und Angiogenese-Signalkaskaden in Wilms Tumoren zu untersuchen, um deren Einfluss v.a. auf das Fortschreiten und die Ausbreitung der Tumoren zu evaluieren. Auch wenn die multivariate Analyse nicht zu relevanten Genkombinationen führte, konnte hier dennoch eine schwache Assoziation der verminderten Expression von TOP2A und TRIM22 mit primären Metastasen oder einer erhöhten Mortalität, sowie der Überexpression von TERT mit der Rezidivbildung bestätigt werden. Interessanterweise stellte sich die Histologie, die derzeit das Hauptkriterium für die Risikoklassifikation darstellt, weder als geeigneter prognostischer Marker für die Beurteilung des Rezidiv- noch des Sterberisikos heraus. Somit sollten Realtime RT-PCR Analysen in Zukunft als weiterer Faktor zur Beurteilung des Rezidiv- und Sterberisikos eingesetzt werden, um eine individuelle Anpassung der Therapie zu ermöglichen. Basierend auf den Ergebnissen der Realtime RT-PCR Analyse wurde der Einfluss der Expression ausgewählter Gene auf Primärkulturen, die aus nativem Wilms Tumormaterial gewonnen wurden, untersucht. Nach der Überexpression von HEY2, EGR1, MYCN und TRIM22 wurden bei allen Zellen hohe Sterberaten beobachtet, v.a. bei HEY2 und EGR1. Leider konnte weder für HEY2 noch für EGR1 der Grund hierfür aufgeklärt werden, allerdings war bei EGR1 weder die Apoptose noch die Seneszenz beteiligt. Im Gegensatz hierzu wurde die Apoptose als entscheidender Mechanismus bei MYCN und v.a. TRIM22 ermittelt. Außerdem scheint bei MYCN ein großer Anteil an Zellen in die Seneszenz einzutreten. Auch wenn diese ersten Untersuchungen an Primärkulturen von Wilms Tumoren eindeutig die Relevanz dieser Gene für die Entwicklung bzw. das Fortschreiten der Tumoren bestätigten, so sind trotz alledem weitere Experimente v.a. in einer größeren Anzahl genetisch unterschiedlicher Primärkulturen nötig, um das endgültige Potenzial dieser Gene aufzuklären. / Wilms tumor (WT), also called Nephroblastoma, belongs to the most common malignant tumors occurring in childhood. Most of these Wilms tumors develop unilaterally (90 – 95 %) and sporadically (98 – 99 %). Unfortunately, only little is known about the molecular background underlying their development with only three genes known so far: WT1, CTNNB1 and WTx. Mutations in WT1 and CTNNB1 occur only in a minor fraction of Wilms tumors of about 10 - 15 % and are often associated with each other, while mutations in WTx can be found in about 30 % of tumors. The genetic alterations of the other tumors are completely unknown. Hence, the aim of this thesis was to identify important regions and genes that are involved in Wilms tumor formation and/or progression and to further characterize their potential as markers for the prediction of certain clinical outcomes. First, chromosome arms 11q and 16q were screened for LOH (= loss of heterozygosity), which means the (partial) loss of the genome in a cell, in a large cohort of Wilms tumors. In both regions LOH rates of about 20 % were detected, but since allele losses did not always start at the same marker in the different tumors it was not possible to delimit any relevant subregions. Since there were significantly higher rates of allele loss in anaplastic and mixed-type (only 11q) tumors and almost no allele loss in epithelial and stromal tumors, 11q and 16q must contain genes that either facilitate the epithelial and stromal differentiation of cells or hamper the appearance of blastemal and anaplastic phenotypes. Otherwise, the obvious possibility to discriminate these histological subtypes by allele loss on 11q and 16q might be explained by a development from different precursor cells. Higher rates of LOH could also be linked to higher risks for relapse and death (11q only), especially when the whole chromosome arms were involved. Therefore, investigation of LOH on 11q and 16q may help to adjust the therapeutic regimens by identifying high-risk patients for relapse and death. A second approach was to reinvestigate the expression of a number of published marker genes in a larger set of Wilms tumors with a uniform method, the realtime RT-PCR. All of the genes were suggested to facilitate classification and/or prediction of certain clinical outcomes. Univariate analysis was performed to screen for relevant genes, followed by multivariate analysis to search for predictive gene combinations. Finally, validation of associations found in the first cohort was performed in a second and independent tumor set. Unfortunately, many of the previously published markers as well as associations of the first tumor set could not be verified in a new and independent tumor set. Nevertheless, it was possible to replicate the results of a number of genes and evidence their prognostic relevance. These included the repression of HEY2 and TRIM22 for high-risk tumors or mortality. Weaker correlations were verified for the repression of TRIM22 and VEGF with the histological risk and for overexpression of TERT and repression of TRIM22 with later relapse. Since the weaker expression of HEY2 and VEGF as well as the overexpression of CA9 was significantly linked to relapse, high malignant tumors or metastasis the hypoxia / angiogenesis pathways should be investigated in Wilms tumors especially with regard to the progression and spreading of tumors. Finally, multivariate analysis substantiated a weak association of repression of TOP2A and TRIM22 with metastasis or death and of overexpression of TERT with subsequent relapse. Most interestingly, histology, the current gold standard used for prediction of risks for relapse and death, could not be verified as potent prognostic factor for neither of them. Hence, realtime RT-PCR analyses can aid in stratification of tumors and prediction of relapse and death risks to intensify therapy for high-risk patients on one hand and to reduce therapy and side-effects in low-risk patients on the other hand. Based on the results of the realtime RT-PCR analyses the expression of several genes was ascertained in primary cell cultures cultivated from native Wilms tumor material. Overexpression of MYCN, TRIM22 and especially HEY2 and EGR1 by viral transduction resulted in high rates of cell death. Unfortunately, the underlying mechanism of death could be determined neither for HEY2 nor for EGR1, though for EGR1 the involvement of apoptosis and senescence could be excluded. In contrast, death in MYCN and especially in TRIM22 overexpressing cells could be attributed to high rates of apoptosis. Furthermore, a large fraction of MYCN cells seem to enter cell senescence and stop to proliferate. These results clearly corroborate the proposed relevance of the investigated genes in the development and/or progression of Wilms tumors. Nevertheless, further experiments in different primary cell cultures of Wilms tumors are necessary to clarify the real potential of these genes.
180

Students' perceptions of career decision-making self-efficacy and family members' work experiences.

Hutchison, Sarah 06 February 2007 (has links)
ABSTRACT The present research study examines the possible relationship between students’ career decision-making self-efficacy (CDMSE) and their perceptions of their family members’ job satisfaction and job insecurity. The present research uses a quantitative, non-experimental, cross-sectional research design, on a sample of 148 subjects drawn from a sample of first year Psychology students from the University of the Witwatersrand, South Africa. The Career Decision Self-Efficacy scale was used to measure career decision-making self-efficacy (Betz & Taylor, 2001), Warr, Cook and Wall’s (1979) Overall Job Satisfaction scale to measure job satisfaction (Short, 1996) and the Job Insecurity scale developed by Ashford, Lee and Bobko (1989) to measure job insecurity. The statistical procedures used to analyse the data, included correlations to test the first hypothesis, which proposed a relationship between students’ CDSME and their perceptions of their family members’ job satisfaction and the second hypothesis, assumed a relationship between students’ CDMSE and their family members’ job insecurity. A Stepwise Multiple Regression was performed to examine the above hypotheses. The results reported a significant relationship between students’ CDMSE and their perceptions of their family members’ job satisfaction. However, there was insufficient evidence to support the relationship between students’ CDMSE and their perceptions of their family members’ job insecurity.

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