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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.
181

A study of the time-dependent modulation of galactic cosmic rays in the heliosphere / Dzivhuluwani C. Ndiitwani

Ndiitwani, Dzivhuluwani Christopher January 2005 (has links)
Time-dependent cosmic ray modulation in the heliosphere is studied by using a two-dimensional time dependent modulation model. To compute realistic cosmic ray modulation a compound approach is used, which combines the effect of the global changes in the heliospheric magnetic field magnitude and the current sheet tilt angle to establish realistic time dependent diffusion and drift coefficients. This approach is refined by scaling down drifts additionally (compared to diffusion) towards solar maximum. The amount of drifts needed in the model to realistically compute 2.5 GV proton and electron and 1.2GV electron and helium intensities, as measured by Ulysses from 1990 to 2004, is established. It is shown that the model produces the correct latitudinal gradients evident from the observations during both the Ulysses fast latitude scan periods. Also, much can be learned on the magnitude of perpendicular diffusion in the polar direction, K┴θ, especially for solar minimum conditions and for polarity cycles when particles drift in from the poles. For these periods K┴θ = 0.12K║ in the polar regions (with K║ the parallel diffusion coefficient)and K┴θ /K║ can vary between 0.01 to even 0.04 in the equatorial regions depending on the enhancement factor toward the poles. The model is also applied to compute radial gradients for 2.5 GV cosmic ray electrons and protons in the inner heliosphere. It is shown that, for solar minimum, and in the equatorial regions, the protons (electrons) have a radial gradient of 1.9 %/AU (2.9 %/AU), increasing for both species to a very fluctuating gradient varying between 3 to 4 %/AU at solar maximum. Furthermore, the model also computes realistic electron to proton and electron to helium ratios when compared to Ulysses observations, and charge-sign dependent modulation is predicted up to the next solar minimum expected in 2007. Lastly the model is also applied to model simultaneously galactic cosmic ray modulation at Earth and along the Voyager 1 trajectory, and results are compared with> 70 MeV count rates from Voyager 1 and IMP8. To produce realistic modulation, this model gives the magnitude of perpendicular diffusion in the radial direction as K┴r/K║= 0.035 and that the modulation boundary seemed to be situated between at 120 AU and 140 AU. / Thesis (M.Sc. (Physics))--North-West University, Potchefstroom Campus, 2005.
182

Essays on the Causal Relationship Between Short-Term and Long-Term Interest Rates

Rahimi, Azadeh 30 May 2014 (has links)
This thesis is about the causal relationship between interest rates. In chapter 1, with the help of time-series econometrics and by applying linear Granger causality tests based on the Toda-Yamamoto approach, the linear causality directions between the federal funds rate and five different interest rates during the last seven business cycles in the U.S. are investigated. We also examine the linear Granger causality directions between the overnight rate and five other interest rates during the last three business cycles in Canada. In chapter 2, the Diks and Panchenko Granger causality test is applied to explore the nonlinear causality effects between the short-term and long-term interest rates. By combining nonlinear causality effects with the linear ones which are found in the first chapter, it is seen that during the related periods in the U.S. and Canada, the most common Granger causality direction between short-term and long-term interest rates is a bidirectional one. Moreover, our findings show that during recent periods, the federal funds rate and overnight rate Granger cause other interest rates significantly. In chapter 3, the rolling window strategy is employed to detect the linear and nonlinear Granger causality relationship between the federal funds rate and the 10-year government bond rate, during different time horizons, investigating whether these causalities change with the passing of time. Our findings show that during different time horizons, there is a significant two-way Granger causality relationship between these interest rates. Although we have a different interpretation of the existence of bidirectional causation between short-term and long-term interest rates, this conclusion provides some support to some post-Keynesian structuralists viewpoints like Pollin (2008). However, Pollin's claim indicating that with the passing of time the significant causality effects of the federal funds rate to the market rates becomes insignificant is not supported by the current thesis findings because our results demonstrate that these causality effects have not been diminishing over the most recent business cycles.
183

Understanding the quality of life of personal care home residents with Alzheimer's disease and related dementias: Family caregivers' perspectives

Rona, Hazel 13 September 2010 (has links)
Manitoba’s population is aging. Trends in personal care home (PCH) use have also changed so that residents today have more cognitive impairments including Alzheimer’s disease and related dementias (ADRD). While quality of life (QoL) has emerged as an important PCH research outcome, this literature is relatively sparse for residents with versus without ADRD. This study was conducted to examine the QoL of PCH residents with ADRD, using a recently developed but as of yet untested framework by Kane and colleagues (1999, as cited in Frytak; Kane 2001, 2003). The specific aims of this study were to gather family caregivers’ perspectives on: (a) the meaning of the six domains that constitute Kane et al.’s ADRD-specific PCH-QoL framework; (b) domains they considered to be more important or lacking from this framework; and, (c) general PCH policies, practices, and activities that currently (or could better) facilitate positive QoL experiences for their loved ones.
184

The impact of aggressive parental disciplinary strategies implemented in childhood on externalizing and internalizing problem behaviour in early adulthood

Taillieu, Tamara L. 18 January 2011 (has links)
Parental use of aggressive discipline, specifically corporal punishment (CP) and psychological aggression (PA), has been shown to increase the risk of problem behaviours in children and adolescents. A major gap in the research concerns our lack of understanding regarding how CP and PA contribute to adverse development in adulthood. Because these techniques do not occur in isolation, a number of protective factors were also considered. Both CP and PA were associated with lower levels of parental warmth/support and responsiveness, and more inconsistency in discipline; whereas high induction was associted with more frequent CP and PA. CP predicted later partner violence, and PA predicted anxiety and lower self-esteem in adulthood, even after the effects of positive parenting were considered. These findings suggest that not only do CP and PA tend to occur within environments that are less conducive to positive development, but also predict problematic outcomes in adulthood even after protective factors are considered.
185

Nedlagda deponier i Västerbottens län : Regional åtgärdsplan och prioriteringslista

Ek, Liselott January 2014 (has links)
Due to national environmental goals, 191 closed landfills were inventoried according to a national methodology for inventory of polluted areas. The inventory took place in thirteen of the municipalities in the region of Västerbotten during the summer of 2013. 159 of the landfills were classified to risk class 3 on a scale of 4. Landfills in this category consist of diverse nature, ranging from adequate coverage but poor placement, to insufficient coverage and visible leakage, but without urgent risk. The purpose of this report was to follow up on the inventory. It resulted in identifying and prioritizing the actions required and a general plan of action for the landfills in the region. The focus was mainly on landfills in class 3, but those in risk class 2 are also included. This report was based mostly on forms for the closed landfills and a survey aimed at regional administrations. The result showed that the most common actions required were clean up, coverage, investigation of leakage and information about the unsuitability of depositing waste, including yard waste, at a closed landfill. A status division of the landfills in class 3 was determined, where the landfills that required actions were assigned the statuses +, 0 or -. Criteria for + includes proximity to vulnerable nature, risk for contamination of drinking water, poor coverage, or visible leakage. The landfills in class 2 should be prioritized for further actions, and after that those in risk class 3 with the + status.
186

Long-Term Health Outcome of Adolescent  Mood Disorders : Focus on Bipolar Disorder

Päären, Aivar January 2015 (has links)
There has recently been an intense debate about the increased rate of bipolar disorders (BPD) in children and adolescents observed in clinical settings. Thus, there is great interest in child and adolescent symptoms of hypomania and whether these symptoms subsequently will develop into BPD. More knowledge about early signs could give insight into the development of the disorder. There are also concerns that hypomanic symptoms in adolescence indicate excess risk of other health conditions. It has been reported that patients with mood disorders have a high consumption of prescription drugs in different ATC classes. The primary objective of this thesis was to better understand the mental health outcome of adolescents with hypomania spectrum symptoms and to identify early risk factors for adult bipolar disorder among adolescents with mood disorders. In order to widen the scope and investigate health outcome of mood disorder in general psychopharmacological outcomes were included. A community sample of adolescents (N=2 300) in the town of Uppsala, Sweden, was screened for depressive symptoms. Both participants with positive screening and matched controls (in total 631) were diagnostically interviewed. Ninety participants reported hypomania spectrum episodes, while another 197 fulfilled the criteria for major depressive disorder (MDD) without a history of a hypomania spectrum episode. A follow-up after 15 years included a blinded diagnostic interview, a self-assessment of personality disorders, and national register data on prescription drugs and health services use. Adolescent mood symptoms, non-mood disorders, and family characteristics were assessed. Univariate and multivariate analyses were used. The results indicate that the phenomenology of the hypomania spectrum episodes during childhood and adolescence per se does not predict adult bipolar disorder. However, having both affective symptoms during adolescence and a family history of bipolar disorder increases the risk of developing bipolar disorders in adulthood. Disruptive disorder in childhood or adolescence as well as family histories of BPD emerged as significant risk factors that differentiated between the future development of BPD and MDD. Adolescents with hypomania spectrum episodes and adolescents with MDD do not differ substantially in health outcomes in adulthood. Both groups are at increased risk for subsequent mental health problems, high consumption of prescription drugs, and high health care use, compared with the control group. The high rates of prescription drugs in many ATC classes found among the former depressed females seem to indicate a series of co-morbid somatic illnesses. Thus, it is important to identify and treat children and adolescents with mood disorders, and carefully follow the continuing course. Characteristics such as disruptive disorders and family history warrant particular attention.
187

Anorectal Malformations : Long-term outcome and aspects of secondary treatment

Danielson, Johan January 2015 (has links)
Faecal incontinence (FI) is defined as the inability to control bowel movements. The causes of FI are many and diverse. One of the more uncommon reasons for FI is Anorectal Malformations (ARMs). An ARM is a congenital anomaly that affects somewhere between 1/2500 and 1/5000 live born babies. Many ARM patients have persistent FI. Several different procedures have been utilised to address this issue. This thesis aims to evaluate (1) the long-term outcome in adulthood of ARMs in relation to the modern Krickenbeck classification, and (2) scope for treating FI with transanal injection with dextranomer in non-animal stabilised hyaluronic acid (NASHA/Dx), in patients both with and without ARMs. All patients treated for ARMs in Uppsala up to 1993 were invited to participate in a questionnaire study of quality of life and function. The study included 136 patients and compared them with 136 age- and sex-matched controls. The Krickenbeck classification was found to predict functional outcome, and ARM patients had more problems with incontinence and obstipation, as well as inferior Quality of Life (QoL), compared with controls.  Thirty-six patients with FI, owing to causes other than ARMs, were treated with transanal submucous injection of NASHA/Dx. The patients were monitored for two years after treatment. Significant reductions in both their incontinence score and the number of their incontinence episodes were achieved.  A significant improvement in QoL was observed in patients who had at least a 75% reduction in incontinence episodes. No serious complications occurred. A prospective study of transanal injection of NASHA/Dx was conducted on seven patients with persistent FI after ARMs. After six months a significant reduction in the number of incontinence episodes was obtained. A significant improvement in QoL was also found. No serious complications occurred. In conclusion, adult patients with ARMs have inferior outcome of anorectal function and QoL compared with controls. NASHA/Dx is effective and appears to be safe in treating FI in general. This effect seems to be the same in selected patients with persistent FI after ARMs.
188

Physical Activity Levels & Correlates 2-6 Years Post-rehabilitation in Cardiac Patients

Khan, Shazareen N. 12 December 2011 (has links)
Many patients do not maintain physical activity (PA) post cardiac rehabilitation (CR),however few studies examine a large enough sample over the long-term. Thus, a retrospective cross-sectional study was carried out to examine PA and its correlates 2-6 years post CR; 584 graduates completed a mailed survey (mean+SD age: 69.8+9.8 years, BMI: 27+5.0 kg/m2, 80% male, 41.4+11.6 months since graduation, 36% response rate). PA was assessed using the Physical Activity Scale for the Elderly (PASE, mean+SD: 122.3+75.9). Seventy five percent of participants met Canadian PA guidelines. Greater PA was significantly associated with male sex, younger age, fear of falling, cholesterol control, self-controlled transportation, marital status, full-time work, rural location, higher VO2max, more comorbid conditions, greater perceived health, PA enjoyment, quality of life (QOL), social support, income, and CR staff support. Age,PA enjoyment, QOL, work status, cholesterol control and CR staff were significant in a multivariate model (R2=0.22, F=18.7, p<0.001).
189

Long-term Complications Associated with Implant-supported Complete Fixed Dental Prosthesis

Shokati, Babak 17 July 2013 (has links)
Rehabilitation of edentulous patients with Implant-supported Complete Fixed Dental Prosthesis (ICFDP) is a well-documented treatment option. This dissertation assessed the relation between the rate of biological/mechanical complications and the type of metal framework alloy, length of cantilever extension. The results showed that long-term clinical outcomes of ICFDP were favorable. While 30% of patients experienced biological complications, 66.6% of the prostheses needed to be repaired during follow-up period. The risk of prosthesis failure and mechanical complications was significantly higher in silver-palladium frameworks as compared with palladium-silver or type IV gold alloys. The length of cantilever was not correlated with the amount of marginal bone loss. The rate of marginal bone loss around anterior implants was higher than that of posterior implants associated with cantilever segments. The treatment improved the patients’ quality of life and 96% of patients would undergo the same treatment again if required.
190

Physical Activity Levels & Correlates 2-6 Years Post-rehabilitation in Cardiac Patients

Khan, Shazareen N. 12 December 2011 (has links)
Many patients do not maintain physical activity (PA) post cardiac rehabilitation (CR),however few studies examine a large enough sample over the long-term. Thus, a retrospective cross-sectional study was carried out to examine PA and its correlates 2-6 years post CR; 584 graduates completed a mailed survey (mean+SD age: 69.8+9.8 years, BMI: 27+5.0 kg/m2, 80% male, 41.4+11.6 months since graduation, 36% response rate). PA was assessed using the Physical Activity Scale for the Elderly (PASE, mean+SD: 122.3+75.9). Seventy five percent of participants met Canadian PA guidelines. Greater PA was significantly associated with male sex, younger age, fear of falling, cholesterol control, self-controlled transportation, marital status, full-time work, rural location, higher VO2max, more comorbid conditions, greater perceived health, PA enjoyment, quality of life (QOL), social support, income, and CR staff support. Age,PA enjoyment, QOL, work status, cholesterol control and CR staff were significant in a multivariate model (R2=0.22, F=18.7, p<0.001).

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