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Bakgrund: Under senare tid har mediedebatten fokuserats kring olika dieters påverkan på viktminskning och välbefinnande. De moderna dieterna har debatterats av läkare, forskare och myndigheter, då extrema lågkolhydratsdieter innehåller alltför mycket fett vilket vissa menar kan leda till framtida folksjukdomar. Syfte: Syftet var att undersöka ett begränsat antal dieters påverkan på viktminskning och välmående samt att belysa betydelsen av en helhetssyn på våra kostvanor. Metod: Denna litteraturstudie är baserad på fyra vetenskapliga artiklar som var relevanta och intressanta för syftet. Resultat: Samtliga av de artiklar som undersökte sambandet mellan olika dieter och vikt visade på en tydlig viktminskning hos alla deltagare. LCHF-dieten gav den snabbaste viktminskningen. När det gäller välmående visade samtliga i alla studiegrupper en förbättring i sitt psykologiska välbefinnande och välmående. Den undersökning som behandlade kostvanor kom fram till att det behövs en helhetssyn på skolmåltiden för att få en optimal måltidsupplevelse med tanke på elevernas hälsa och välbefinnande. Slutsats: Undersökningen visar på en tydlig viktminskning oavsett diet och att det fysiska och psykologiska välbefinnandet förbättrades, det fordras däremot ytterligare forskning för att studera de olika dieternas långsiktiga påverkan samt att det krävs en helhetssyn på våra kostvanor redan i unga år för att leva ett friskare och mer välmående liv. / B-uppsatser

The purpose of this investgation was to study the effects of repeated weight loss and physical training on the plasma levels of testosterone, growth hormone, insulin and cortisol. A further purpose of this study was to determine if changes in plasma hormone concentrations could be avoided through a nutritional education program and the addition of nutritional supplements to the diet. Lastly the effects of acute and seasonal weight loss upon mean anerobic power, peak power, and percent fatigue were measured.MethodsA total of 34 adolescent high school wrestlers ranging age from 14 to 18 years, were pair matched for age, size, percentage weight loss, and skill level (varsity or JV) and then randomly assigned into a control and treatment group. The treatment group recieved a nutritonal education program and nutritional supplements. Blood samples were taken four times throughout the study period: once in the preseason (October 14), twice in December (Dec. 7 and 14), and once in January (Jan. 13). The blood was drawn at the same time each morning after an 8 hour fast. The blood was analyzed to detect changes over time and between groups for hemoglobin, hematocrit, and plasma levels of insulin, cortisol, testosterone, and growth hormone. The wrestlers were also measured for caloric and nutrient intake, weight, height, body fat percentages, and for arm power with the Wingate test. The experimental design consisted of a pretest-posttest randomized groups test design. The hormone and power data were analyzed with a repeated measures ANOVA, and a probability level of 0.05 or above was chosen as statistical significance. Polynomial contrasts were used to determine whether significant differences over time followed linear, quadratic, or cubic trends. Post hoc tests were also used to determine where the difference did exist.ResultsThere were no significant (p<0.05) differences between the treatment and control groups in any variable tested. Over the experimental period, each group showed significant (p<0.05) decreases in weight, percent body fat, and fat free weight. No significant changes (p<0.05) in any of the power indicies occurred, but specific trends were apparent. Both groups had reductions in their absolute peak and mean power, and increases in their relative peak and mean power. Changes in percent fatigue and fatigue slope were inconsistent and nonsignificant. Serum concentrations of cortisol and insulin showed significant (p<0.05) decrements over the investigative period. The decline in serum growth hormone levels approached significance (p = 0.085), and serum testosterone levels showed a nonsignificant decreasing trend. Hormone levels per kilogram free fat weight were not changed, along with testosterone to cortisol ratios, hemoglobin and hematocrit levels.ConclusionsThe treatment of consuming a nutritional beverage (Exceed) and information on proper dieting did not produce a significant (p<0.05) difference between the groups. Over time the wrestlers lost significant amounts of weight, body fat, and fat free weight due to significant decreases in the intake of calories in the form of fat, protein and carbohydrate. There were also significant decreases in plasma levels of insulin and cortisol. These results indicate that weight loss over a wrestling season may significantly alter plasma hormone levels. / School of Physical Education

Transmissible spongiform encephalopathies (TSEs) or prion diseases are defined by infectivity and by the pathological damage they produce in the central nervous system (CNS), typically involving spongiform degeneration or vacuolation, deposition of abnormal PrP (PrPSc), glial activation and neuronal loss. Much of our understanding of the TSEs has derived from the study of murine scrapie models. The molecular basis of pathological changes is not clear, in particular the relationship between the deposition of PrPSc and neuronal dysfunction. A typical feature of TSE disease is neuronal loss, although the mechanisms leading to this loss are poorly understood. Apoptosis has been proposed as an important mechanism of TSE associated cell death, but which pathways are involved are still to be determined. The main aims of this thesis are to investigate the progression of the characteristic neuropathological changes observed in the TSE infected brain and to analyse the mechanisms involved in neuronal loss. In this study two contrasting scrapie mouse models were used : the ME7/CV model , and the 87V/VM model in which neuronal loss is targeted to different areas of the hippocampus, the CA1, and CA2 respectively. The role of the caspase-dependent pathway of apoptosis in the neuronal loss was investigated. The results of analysis of pro-apoptotic markers of disease in the two scrapie mouse models differed. The results observed in the ME7/CV scrapie mouse model suggest that apoptosis may not be the main mechanism of neuronal loss, whereas the 87V/VM model showed some indication that apoptosis may be involved. Detailed studies in the progression of neurodegenerative changes in the ME7/CV scrapie mouse model revealed that the initial pathological change observed in the hippocampus was the deposition of PrPSc followed by a glial response, spongiform change and subsequent neuronal degeneration. The role of the cytoskeleton and synaptic dysfunction in the neuronal damage observed in the CA1 of the ME7 infected hippocampus was analysed. Cytoskeletal disruption was observed in the post-synaptic dendritic spine, and the apical dendrites of CA1 neurons at 160days, a time point at which neurons are known to be lost. Changes in the expression of the pre-synaptic protein, synaptophysin and the post-synaptic protein PSD-95 were not observed until the terminal stage of disease when the neuronal loss is profound. In conclusion, this research suggests that the mechanisms of neuronal loss may follow different biochemical pathways, which might not necessarily involve an apoptotic mechanism. Cytoskeletal disruption in the post-synaptic dendritic spine plays a major role in the neuronal dysfunction observed in ME7 infected CA1 neurons, although the post synaptic density does not seem to be involved .Pre-synaptic changes and disruption to the innervation of CA1 neurons is not apparent until the end stages of disease. The trigger for this cytoskeletal disruption and the subsequent neuronal loss may be the early deposition of PrPSc in the extracellular space but the precise mechanisms involved are still to be elucidated. The identification of the key events involved in the mechanisms of neruodegeneration in TSE diseases may lead to the development of therapeutic strategies to inhibit the neurodegenerative process.

This study investigated the effectiveness of aversion therapy to help subjects achieve and maintain a weight loss. The aversion therapy made use of an avoidance conditioning procedure. Slides of fattening foods were paired with the possibility of receiving an electric shock in an attempt to induce anxiety. Slides of non-fattening foods were paired with shock avoidance and consequent anxiety relief.

This research study had two distinct objectives. The first objective was to determine in which areas in South African banks the most severe operational risk losses are likely to occur (based on the Basel II seven loss event types and eight business lines). Severity was assessed based on single operational risk events that might have significant monetary values attached to them. The likely frequency of single operational risk events was also assessed. The investigation of the aforementioned research problem was explorative and quantitative of nature, as the researcher made extensive use of survey research in the form of a questionnaire to all registered banks. The second part of the research study’s objective was to assess the range of practices in collecting internal loss data for operational risk purposes as required by Basel II. This part was approached from a qualitative perspective, by benchmarking the research findings against the Basel II text, the researcher’s experience in risk management in banks, the Basel Committee on Banking Supervision’s Sound Practices for the Management and Supervision of Operational Risk, and related literature. The literature review, including reference to certain surveys and studies, focuses on the main concepts of operational risk within banks that are pertinent to the research problem. The literature review also includes several references to the Basel II text and other relevant publications and papers issued by the Basel Committee on Banking Supervision. The research results revealed that respondents in South African banks believed that ‘business disruption and system failures’ is the loss event type that is likely to result in the most severe single operational risk loss. ‘Trading and sales’ scored the same high average rating as ‘business disruption and system failures’ as the business line where the most severe single operational risk loss is likely to occur in South African banks. ‘External fraud’ and ‘execution, delivery and process management’ scored the highest average ratings as the loss event types where the most frequent operational risk losses are likely to occur. Respondents indicated that ‘retail banking’ is the business line where the most frequent single operational risk losses are likely to occur in South African banks. Based on the above-mentioned findings the researcher recommends that these high-risk areas be highlighted to the Bank Supervision Department of the South African Reserve Bank, the boards of directors and senior management of banks in order for them to strengthen banks’ internal controls. The researcher recommends the inclusion of near misses and opportunity cost in operational risk loss databases. Banks should at least capture the date of the discovery of an operational risk event as this represents acceptable practice among the majority of banks. Operational risk losses should be assigned to the multiple business activities in which it occurred on a pro-rata basis. All recoveries of operational risk losses should be processed separately, but associated with the original loss event. Replacement cost is seen as the most appropriate way to capture gross loss amounts for the damage to fixed assets. The researcher encourages the recording of overtime cost for fixing systems failures. Market risk losses due to operational risk events should be treated as market risk losses, while loan-related losses due to operational risk failures should be treated as credit risk losses by banks. The researcher’s view is that banks should set different thresholds for the collection of operational risk losses for its various business units based on each business unit’s operations and nature of business. Banks should, as a starting point, map operational risk events to the Basel II 8x7 matrix. Operational risk losses should be assessed by both legal entity and on a consolidated basis.

The master thesis deals with the advanced methods for estimating credit risk parameters from market prices: probability of default (PD) and loss given default (LGD). Precise evaluation of these parameters is important not only for banks to calculate their regulatory capital but also for investors to price risky bonds and credit derivatives. We provide forward looking reduced-form analytical method for calculation of PD and LGD of corporate defaultable bonds based on their quoted market prices, prices of equivalent risk-free bonds and quoted credit default swap spreads of the issuer of these bonds. This is reversed to most of the studies on credit risk modeling, as aim is not to price instruments based on estimated credit risk parameters, but to calculate these parameters based on the available market prices. Furthermore, compared to other studies, the LGD parameter is assumed to be endogenous and we provide the method for its simultaneous calculation with the probability of default. Finally, using developed methods, we estimate implied PD and LGD for five European banks assuming that the risk is priced correctly by other investors and the markets are efficient. JEL Classification: C02, C63, G13, G33 Keywords: credit risk, loss given default, probability of default, credit default swap Author's...

M.P.H.(Occupational Hygiene), Faculty of Health Sciences, University of the Witwatersrand, 2009 / BACKGROUND Hearing loss from occupational exposures is a serious and widespread problem in underground nickel mining. This is a major contributor to compensable illnesses resulting not only in costly compensation but posing a serious threat to safety and also reducing the quality of working life. OBJECTIVES The objectives of this study were to identify the prevalence of noise induced hearing loss amongst underground nickel miners with at least 5 years of exposure as well as describe some risk factors for noise induced hearing loss in this occupational setting. METHODS One hundred and sixty eight underground nickel miners, or one hundred percent of eligible workers’ medical records with baseline and periodic audiograms were reviewed to identify the prevalence of noise induced hearing loss and also evaluate some of the risk factors for noise induced hearing loss namely age, duration of exposure, use of oto-toxic agents, high ambient noise levels, hearing impairment, high pre-employment noise levels, history of acoustic trauma, history of ear injury and history of previous military, hunting or police work. One hundred underground mine workers were interviewed to give insight into their pre-employment noise exposure history, non-occupational noise exposure, perceived noise levels at work, knowledge of noise hazards and their control, and the use of hearing protection devices. One hundred and sixty eight workers were observed in their various tasks over a 14 day period and their work practices were scored to identify compliance to the use of hearing protective devices as well as confirm the presence or absence of oto-toxic agents like heavy metals and solvents. Data were analyzed using the EpiInfo software version 3.4.3: 1997 as well as the online statistical package Vassar Stats. RESULTS A noise induced hearing loss prevalence of 27.4% was identified with 42% being mild hearing loss, 28.8% moderate hearing loss and 28.8% moderate to severe noise induced hearing loss. The highest noise induced hearing loss prevalence of 60% was found in the 50 and above years age group whilst 45.5% was found in the 40 – 49 year age group, 20% in the 30- 39 year age group and 5.3 % in the 20 – 29 year age group. This difference was statistically significant ( 2 1 = 19 p < 0.001). Age with a 2 = 24, p< 0.002 and duration of exposure with a 2 = 19, p< 0.001 were found to be major determinants of noise induced hearing loss at the mine. Jackhammer operation and machine operation were found to be associated with noise induced hearing loss compared to the other tasks; Tukey’s Honestly Significant Difference 0.05 = 12.23 p<0.01. The following risk factor was found to be related to noise induced hearing loss: use of quinine OR = 2.16 with CI 95% = 0.12 – 1.72. Ninety seven percent of the workers confirmed exposure to high noise levels. The knowledge of noise induced hearing loss at the mine was high (85%). Compliance with the use of hearing protective devices was found to be low with optimum usage only being achieved during the last 4 days of the 14 day observation period. CONCLUSIONS These findings attest to the relatively high prevalence of noise induced hearing loss at the mine. It can also be concluded that though the knowledge of noise induced hearing loss is high, the effective use of hearing protection still needs improvement through the implementation of comprehensive hearing conservation programs which adequately screen workers at pre-employment stage as well as consider the workers’ perceived knowledge, attitudes as well as practices in an occupational setting.