• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2448
  • 805
  • 733
  • 219
  • 145
  • 114
  • 78
  • 57
  • 47
  • 45
  • 41
  • 32
  • 30
  • 25
  • 17
  • Tagged with
  • 5591
  • 1364
  • 1167
  • 1057
  • 954
  • 874
  • 872
  • 660
  • 618
  • 586
  • 569
  • 473
  • 465
  • 452
  • 397
  • 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.
331

Factors Related to the Migration Preferences of Utah's 1980 High School Seniors

LaCognata, A. John 01 May 1983 (has links)
This study examines the personal migration preferences of Utah high school seniors in 1980 and their relationship to perceived parental preferences, family status, length of residence, religion, sex, and type of residence. A focal area of the thesis is an examination of the consistency between personal preferences and preferences of parents as perceived by the youth. The primary data used for this study came from a sample survey of 1980 high school seniors who were selected using a stratified sampling technique. Cross-tabulations were used with chi square to test for significance of association. The results of this study suggest that parental preferences play an important part in influencing the decision-making process of youth contemplating migration. The research suggests that the plans of metropolitan youth are more consistent with the perceived preferences of their parents than are those of nonmetropolitan youth. The research also suggests that the plans of LDS (Mormon) youth are more consistent with their parents perceived preference as compared to the plans of non-LDS youth. With respect to personal preferences, Utah youth living in nonmetropolitan areas prefer to migrate more often than metropolitan youth. Research also shows that males, LDS youth, youth from intact families and long-term residents all prefer to stay more often in their present place of residence when compared to females, non-LDS youth, youth from broken families and short-term residents.
332

Economic Feasibility of Wind Turbine's Anti-Icing Systems Development and application of a simple heuristic method and tool

Klemm, Maria January 2014 (has links)
Wind energy projects in cold climate areas are more and more favoured due to the presence of high wind potential and the availability of land in those areas. A serious problem, however, is the impact of icing on the wind turbine and on the energy production. The main objective of this Thesis is to present the available options for mitigating the risks of wind turbines’ blade icing and to evaluate the investment of the wind turbines’ anti-icing systems. To this end, a heuristic algorithmic method has been developed as well as a simple computational tool in order to assess the economic feasibility of anti-icing systems. The method has subsequently been applied in three case studies and relevant conclusions have been drawn Initially a literature review has been conducted that encompassed issues like the direct and indirect impacts of icing on wind turbines (reduced yield, increased loads and noise emission, health and safety risks, etc.), the difficulties of estimating icing formulation and icing production losses and the anti-icing and de-icing systems and their functionality, advantages and disadvantages. Subsequently, the heuristic algorithmic method has been developed which is based on estimating the energy production of a wind turbine for three scenarios - with no icing occurring, with icing but without any anti- and de-icing system installed and with an anti-icing system installed – followed by a sensitivity analysis of the economic performance parameter, the simple pay-back period. The method has been accommodated in a simple computational excel-based tool and has been applied to three case studies located in the north Norway, in central Sweden and in south Finland. The production losses related to icing are in the expected ranges typical for the geographic location and so is the economic performance parameter which indicate that the investment in an anti-icing system is recommended for the three case studies. Results showed that the wind resources, the electricity export price and the annual icing hours are the parameters that determine the feasibility of an anti-icing system for a wind farm project. Wind energy projects in cold climate areas are more and more favoured due to the presence of high wind potential and the availability of land in those areas. A serious problem, however, is the impact of icing on the wind turbine and on the energy production. The main objective of this Thesis is to present the available options for mitigating the risks of wind turbines’ blade icing and to evaluate the investment of the wind turbines’ anti-icing systems. To this end, a heuristic algorithmic method has been developed as well as a simple computational tool in order to assess the economic feasibility of anti-icing systems. The method has subsequently been applied in three case studies and relevant conclusions have been drawn Initially a literature review has been conducted that encompassed issues like the direct and indirect impacts of icing on wind turbines (reduced yield, increased loads and noise emission, health and safety risks, etc.), the difficulties of estimating icing formulation and icing production losses and the anti-icing and de-icing systems and their functionality, advantages and disadvantages. Subsequently, the heuristic algorithmic method has been developed which is based on estimating the energy production of a wind turbine for three scenarios - with no icing occurring, with icing but without any anti- and de-icing system installed and with an anti-icing system installed – followed by a sensitivity analysis of the economic performance parameter, the simple pay-back period. The method has been accommodated in a simple computational excel-based tool and has been applied to three case studies located in the north Norway, in central Sweden and in south Finland. The production losses related to icing are in the expected ranges typical for the geographic location and so is the economic performance parameter which indicate that the investment in an anti-icing system is recommended for the three case studies. Results showed that the wind resources, the electricity export price and the annual icing hours are the parameters that determine the feasibility of an anti-icing system for a wind farm project.
333

Vitamin D and Age-Related Macular Degeneration

Hemphill, Mandy 01 January 2017 (has links)
Age-related macular degeneration (AMD) is the leading cause of vision loss in individuals aged 50 years and older and is estimated to affect as many as 11 million individuals in the United States. The purpose of this study was to examine the association between vitamin D and AMD disease progression. The life course epidemiology framework model was used to explore how vitamin D level as a risk factor may have an association to AMD disease through time. Data in the 2005-2008 National Health and Nutrition Examination Survey (NHANES) database were collected on vitamin D levels and identified stages of AMD level based on graded fundus eye exams from an available sample size of 5,604 participants. A quantitative cross-sectional study approach was used to address this gap in knowledge. A bivariate analysis was used to examine each independent variable (age, race/ethnicity, smoking status, and diabetes) to the dependent variable AMD from the 2005-2008 NHANES dataset. A multivariate logistic regression analysis was performed with AMD including each independent variable found to be significant. The findings from this study failed to suggest an association between vitamin D levels to AMD, with or without the covariates included in the model. There was not an association found between vitamin D level and presence of AMD. An association was found between age, smoking, and race to presence of AMD in each of the bivariate models. The findings from this study could be used for positive social change by encouraging medical and public health agencies to target screening programs at high-risk age, smoking, and race groups. There remains to be conflicting data in the literature. This study adds to the body of literature suggesting that higher levels of vitamin D are not necessarily beneficial as they pertains to AMD.
334

Regulation of dynamin-related protein 1-mediated mitochondrial fission by reversible phosphorylation and its contribution to neuronal survival following injury

Slupe, Andrew Michael 01 May 2014 (has links)
Mitochondria are dynamic organelles that constantly undergo opposing fission and fusion events which impact many aspects of mitochondrial and cellular homeostasis including bioenergetic activity, calcium buffering and organelle transport. The large GTPase dynamin-related protein 1 (Drp1) acts as a mechanoenzyme to catalyze fission of mitochondria. Drp1 activity is regulated through a series of reversible posttranslational modifications. Phosphorylation of the conserved serine residue, S656, by cAMP dependent protein kinase A (PKA) acts as a master regulator of Drp1 activity. Two phosphatases oppose PKA by dephosporylating Drp1 S656, a mitochondrial isoform of protein phosphatase 2A and the calcium-calmodulin dependent phosphatase calcineurin (CaN). Here I report the characterization of a conserved CaN docking site on Drp1, an LxVP motif, just upstream of the Drp1 S656 site. Mutational modification of the Drp1 LxVP motif resulted in selective bidirectional modulation of formation of the CaN:Drp1 complex. Stability of the CaN:Drp1 LxVP motif mutant complexes was qualitatively described by affinity purification and quantitatively described by isothermal titration calorimetry. Stability of the CaN:Drp1 complex was found to directly correlate with Drp1 S656 dephosphorylation kinetics as demonstrated by studies conducted in vitro and in intact cells. Further, the CaN:Drp1 signaling axis was shown to shape basal mitochondrial morphology in a heterologous cell line system and in primary hippocampal neurons. Finally, disruption of the CaN:Drp1 signaling axis was found to protect neurons from oxygen-glucose deprivation, an in vitro model of ischemic injury. While these results suggest that the CaN:Drp1 signaling axis may be a potential target for neuroprotective therapeutic exploitation, the mechanism by which disruption of the CaN:Drp1 signaling axis specifically and mitochondrial elongation generally results in resistance to ischemic injury remains unknown. Additional studies reported here demonstrate that mitochondrial fragmentation remains a prominent feature of injured neurons regardless of the fidelity of the CaN:Drp1 signaling axis. Mitochondrial fragmentation at the time of injury was found to occur in a Drp1-independent manner. Chronic mitochondrial elongation was also found to leave unaltered the ability of neurons to detoxify reactive oxygen species, buffer intracellular calcium and supply ATP for homeostatic function.
335

An Analysis of the Work Related Fatalities in Utah as Reported to the Utah Industrial Commission for the Years 1976-1978

Swiss, Dale A. 01 May 1979 (has links)
It was the objective of this study to determine the common denominators involved with the work-related fatalities and their strengths. An analysis using the x2 statistic was conducted on all the work related fatalities reported to the Utah Industrial Commission during the period January 1, 1976, through December 31, 1978. It was determined that Age and Time on the Job were the two areas with the greatest significance difference as common denominators. It was concluded that there was a need for training programs to offset the effects of both age and time on the job.
336

Boron Composition of Alfalfa in Utah as Related to Soils and Irrigation Waters

Radtke, Robert N., Jr. 01 May 1986 (has links)
Eighteen field plots at 15 locations were selected throughout the state to evaluate the status of the boron content in irrigation waters, soils, and alfalfa (Medicago sativa) plant tissue under irrigated conditions. No boron deficiency symptoms were observed in any of the alfalfa plants at any of these locations, nor were any of the plant tissue boron levels inadequate. Only two locations were found in which the alfalfa plants exibited toxicity symptoms. These locations were along the Indian and Antelope Creeks in Duchesne County which contain high boron levels in the water. All the alfalfa and soil tested and irrigated by either Indian or Antelope Creek waters are the only ones tested and found to contain, naturally occuring, high levels of boron in Utah. The light sandy soils were found to contain less available boron than the heavier clay soils. The sandy soil of the Grand County location at Moab showed no available soil boron, while the clayey soils in Duchesne County irrigated with high boron waters were the only soils found to contain excessive levels of available soil boron. The application of 2.8 kilograms of boron per hectare in the form of Solubor significantly increased the available soil boron content by 19.07 percent in the Cache County plots. The 12 alfalfa varieties grown in the Morgan and Tooele County plots showed significant differences with respect to location and tissue boron contents when the results of the two locations were combined. Overall, variety desert had the highest average boron content of 69.5 milligrams boron per kilogram and AS-49R contained the lowest boron content (Y=69.91+13.64X; R2=0.79) or the available soil boron content (Y=63.15+7.66X; R2=0.82).
337

Diversity-Related Experiences and Academic Performance Among Ethnic Minority College Students

Blume, Amabda K. 01 May 2016 (has links)
Students of color experience numerous educational disadvantages compared to White students. These disadvantages begin in elementary school and continue into college and adulthood. Ethnic minority students typically have less resources available to them than White students and are typically less prepared for college—academically and financially. Once students of color enroll in college, they face additional barriers due to discrimination and negative attitudes towards diversity. These factors play a key role in student engagement and persistence. The campus racial climate of a university, defined as the overall racial environment of the campus, has been shown to strongly influence students’ feelings of belonging to an institution. This study examined the links among experiences of discrimination, campus openness to diversity, multicultural experiences, academic success, and feelings of school belonging for students of color, in order to identify ways in which we can improve the educational experiences of disadvantaged students. The current study found evidence that many diversity-related experiences such as cross-racial interactions, campus racial climate, cocurricular diversity activities, and discrimination, strongly influenced feelings of school belonging for students of color. These findings add support to previous research that suggests that diversity experiences on college campuses play a significant role in making students feel welcome at an institution. However, diversity-related experiences examined in this study appeared to have little correlation to academic performance and retention. School belonging did not correlate with academic performance. It seems students’ grades may be better explained by internal factors, like motivation, rather than external factors, like the campus environment. Perceptions of more negative cross-racial interactions and more discrimination experiences were linked with more negative perceptions of the campus racial climate. Campus racial climate was linked to students’ desire to pursue higher education in the future. As the amount of positive cross-racial interactions students experienced increased, so did the amount of negative cross-racial interactions. This suggests that higher levels of cross-racial interactions result in both positive and negative experiences. More cross-racial interactions and cocurricular diversity activities were associated with more experiences of discrimination. This suggests that students of color are likely to experience discrimination when interacting with persons of different racial backgrounds or engaging in conversations related to diversity. Overall, diversity-related experiences linked to feelings of school belonging more than academic performance. Findings provide guidance for college-based initiatives to improve campus racial climates, in order to create more welcoming environments for students of color.
338

Productivity of Two Utah Deer Herds as Related to Nutrition

Pack, Clarence Leon 01 May 1976 (has links)
A study of mule deer occupying deer management units 53 and 54 in south central Utah was conducted from August, 1971 to May 1974 to determine food habits, caloric requirements, dietary nutritional levels, and productivity. Transects, fecal analyses, weight data, classification counts, and forage analyses were used to accomplish these objectives. Food habits of deer on the two units were similar, except for higher use of scrub oak on unit 53 and higher use of snowberry on unit 54. Deer on unit 54 were significantly larger than those on unit 53. Thus, their caloric requirements also were significantly higher. Deer productivity and the nutritional quality of deer diets on unit 54 were lower than on unit 53.
339

The Effects of Parental Modeling on the Health-Related Behaviors of American Indian Adolescents: A Culturally Specific Investigation of Social Learning Theory

Williams, Amy Jo 01 May 2001 (has links)
Health-compromising behavior is a leading cause of death among American Indian (Al) adolescents. Examples of these behaviors include: smoking, alcohol consumption, drug use, and lack of seatbelt use. Theories that predict which Al youth are most at risk for executing these behaviors are needed. Social learning theory (SL T) has shown adolescents' behaviors are sometimes highly correlated with their parents' behaviors across different ethnic groups. However, there has been little previous research done with Als. The present study attempted to determine if SL T was applicable to Al adolescents and their parents with regard to four health-related behaviors: cigarette smoking, alcohol consumption, seatbelt use, and religiosity. The first three were chosen because of the high number of Al adolescent deaths associated with them. Religiosity was included because high religiosity scores have been shown to negatively correlate with health-compromising behaviors in some studies. The present study provided partial support for SL T when applied to Al youth. For example, there were positive correlations found between parents' smoking and if the youths have ever smoked regularly or smoke currently. Little support was found for SL T with regard to alcohol consumption (i.e., the overall correlation was not significant). The exception to this was when daughters were correlated with fathers. How often the father drank and if he binged were positively correlated with how often the daughter drank and if she ever binged. There were strong correlations between parents' seatbelt use and similar use of their adolescents, thus supporting the theory. Also, strong positive correlations were found between the religiosity of the parents' and the youth. Further, religiosity did show negative correlations with health-compromising behaviors among the youth. There was also a sex difference found, with female youth having stronger negative correlations than the male youth. There were 290 Al adolescents in this nationally representative sample, 136 mate and 154 female. All the behaviors were measured via self-report, as was the identification of the adolescent's ethnicity. Limitations of this research, implications for future research, and areas for prevention/intervention with Al youth at risk are discussed.
340

The relationship between spirituality, health related quality of life and occupational balance among adults with chronic diseases

Parker, Yasmeen January 2019 (has links)
Magister Scientiae (Occupational Therapy) - MSc(OT) / Background: One of the most significant current discussions in public health and occupational therapy is the challenges facing adults with chronic diseases. Adults living with chronic diseases experience challenges of activity limitations and occupational disruptions which may influence their health, quality of life and well-being. Chronic diseases seem to have implications for adults’ areas of occupation, client factors and performance patterns as well as performance skills. Spirituality is considered as important in the lives of adults living with chronic diseases as a coping strategy assisting them to deal with the challenges of life in relation to physical, social, emotional and functional well-being. Despite the importance of spirituality in adults with chronic diseases, there is little known about the relationship between spirituality, health-related quality of life and occupational balance among adults with chronic diseases in the Western Cape, South Africa. Aim: The aim of the study was to examine the relationship between spirituality, healthrelated quality of life and occupational balance from the perspectives of adults living with chronic diseases. Methods: A sequential exploratory mixed methods two phase design approach was used for the purpose of the study. Thus, to examine the perspectives and determine the relationship on spirituality, health related quality of life and occupational balance of adults living with chronic diseases. Furthermore, to explore and describe the perceptions of adults with chronic diseases regarding the relationship between spirituality, health related quality of life and occupational balance.

Page generated in 0.0338 seconds