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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.
71

Diet, acid-base status and the metabolic response to high intensity exercise

Greenhaff, Paul Leonard January 1988 (has links)
The aim of these experiments was to investigate the influence that dietary manipulation has upon acid-base balance and substrate availability at rest and during high intensity exercise. It was hoped to identify some of the mechanisms that may control the utilisation of energy substrate and influence the onset of fatigue during high intensity exercise. A pattern of dietary and exercise manipulation intended to alter carbohydrate (CHO) and fat availability was undertaken during the first two experiments. In addition to influencing energy substrate availability, the diet and exercise regimen also significantly influenced resting acid-base balance and high intensity exercise capacity. The reduction in exercise performance afer administration of a low CHO, high fat, high protein diet may have been due to the diet-induced acidosis produced by this diet. However, it is also probable that glycogen availability was influencing exercise performance in this situation. A fixed period of exercise under the same experimental conditions indicates that a higher than normal muscle glycogen content may dictate the pattern of substrate utilisation during high intensity exercise. In a second series of experiments it was demonstrated that dietary manipulation alone will influence acid-base balance and exercise capacity. A high fat, high protein diet will produce a metabolic acidosis but will not influence total muscle glycogen content. In this situation, it is unlikely that a reduction in high intensity exercise performance can be attributed to the availability of muscle glycogen. It is possible that a change in fat availability, rather than muscle glycogen content, will influence the pattern of substrate utilisation during high intensity exercise. However, it is unlikely that a change in fat availability will be responsible for the reduction in exercise capacity recorded after a high fat, high protein diet. The reduction in exercise capacity may be the result of a diet-induced acidosis. Although it is unlikely that dietary acidosis will influence H+ efflux from muscle it may influence pre-exercise muscle buffering capacity. The resulting greater decline in muscle pH during exercise after a high fat, high protein diet may influence muscle function: firstly, by inhibiting the activation of muscle contraction which is due possibly to a reduction in the release of Ca2+ from the sarcoplasmic reticulum and a reduction in the affinity of the myofilaments to Ca2+. Secondly, by inhibiting muscle relaxation which is thought to result from a disruption in actin-myosin corss-bridge separation and a reduction in the rate of Ca2+ removal from the myofibril cytoplasm. Thirdly, by inhibiting muscle glycolysis at the point of PFK. Finally, there is some evidence to suggest that the rate of muscle lactate efflux and/or the metabolic fate of lactate produced during high intensity exercise are different from normal after a period of dietary manipulation.
72

Foraging ecology of goosander (Mergus merganser) and red-breasted merganser (M. serrator) ducklings in north east Scotland

Alexander, Gavin D. January 1995 (has links)
Fish populations were sampled by electrofishing at a variety of sites on the Rivers N. Esk (1992-3) and Dee (1993-4) for comparison with sawbill duckling diets from the same rivers. Sampling methods are described and discussed in relation to other methods and in terms of possible biases. Within electrofished samples species distribution were similar on the two rivers, but more fish were caught per unit effort on the N. Esk. Catch results are described in terms of fish numbers and catch weights of each species from different sections of river and from different sampling times over the summers. Special attention is paid to the distribution and size frequency of salmon, because of their importance in the fish communities of the two rivers and as food for sawbill ducklings. The diets of goosander and merganser ducklings on the study rivers are quantified in terms of species of prey in the diet, size/age classes of fish and relative proportions of these species and classes. Estimates of diet are made from the stomach contents of samples of ducklings. Species composition of the diets are then related to the distribution of fish in those parts of the rivers in which the ducklings forage. Sizes of fish in the diets are then related to the sizes of fish in the duckling foraging areas, taking into account the changes in fish size with location and overtime, and the size (and approximate age) of ducklings. For comparison with diets, fish length data from electrofished samples was interpolated by regression between pairs of consecutive samples and adjacent river sections. This provided expected mean river fish lengths for the dates and locations at which broods were sampled.
73

Genetic polymorphisms in folate and xenobiotic metabolism and susceptibility to colorectal cancer

Brockton, Nigel Trevellyan January 2003 (has links)
Colorectal cancer (CRC) is the second most common cancer, in both sexes, in developed countries and the incidence rates are rising in many populations. Less than 10% of cases are thought to be due to recognised familial syndromes: Familial Adenomatous Polyposis (FAP) and Hereditary Non-Polyposis Colorectal Cancer (HNPCC). Epidemiological studies suggest that dietary factors play an important role in the aetiology of CRC; disease incidence is inversely associated with diets high in folate and has been positively associated with red meat consumption. Folate is important in DNA methylation and synthesis. The increased risk associated with red meat is proposed to be due to the formation of heterocyclic amines during cooking rather than meat consumption per se. The current study, a population-based case-control study (269 case and 408 control subjects) was carried out in the Grampian region and investigated polymorphisms in genes involved in folate and xenobiotic metabolism. Inter-individual differences in the activation and detoxification of xenobiotics and the metabolism of folate might alter risk of CRC. Mouthwash samples were collected from all participants and genomic DNA was extracted for genotypic analysis of MTHFR, CYP1A1, NAT2, GSTM1 and GSTT1. Homozygous possession of the MTHFR A1298C substitution was associated with a reduced risk of colon cancer. The reduced risk of rectal cancer associated with possession of the MTHFR C677T substitution approached statistical significance. A proposed mechanism is presented to explain the inverse association between CRC and MTHFR allelic variants. The CYP1A1 C2453A substitution was inversely associated with CRC risk. No significant alteration of risk was associated with deletions of GSTM1 or GSTT1 genes or acetylation status imputed from NAT2 genotype. Genomic DNA extracted from mouthwash samples, collected by post from an elderly population, was effective as template for PCR/RFLP methods of genotyping.
74

Diet of nesting African Crowned Eagles Stephanoaetus coronatus in emerging and forest–savanna habitats in KwaZulu-Natal, South Africa

Malan, G, Strydom, E, Schulz, S, Avery, G 23 May 2016 (has links)
Abstract The aim of this study was to investigate the species composition of prey caught in the forest, savanna and emerging habitats in which African Crowned Eagles Stephanoaetus coronatus breed in KwaZulu-Natal province, South Africa. At the 17 nest sites, the remains of 195 prey individuals were collected. The five dominant prey species caught were Rock Hyrax Procavia capensis, Vervet Monkey Chlorocebus pygerythrus, Blue Duiker Philantomba monticola, Greater Canerat Thryonomys swinderianus and Bushbuck Tragelaphus scriptus. All of these species respond positively to urban expansion. Only eagles that nested inside protected areas were recorded preying on domestic animals. In terms of biomass, Bushbuck was one of the dominant taxa, and the remains of an estimated 28.8 kg Bushbuck ram was found under a nest. The surprisingly high proportion of Rock Hyraxes and low proportion of Vervet Monkeys caught in emerging habitat may indicate that African Crowned Eagles nesting in this habitat are adapting to a more specialised feeding strategy compared with those nesting in habitats that are more natural. Future studies should investigate how and why prey proliferates in emerging habitats and examine the association between land uses and the diet of African Crowned Eagles.
75

The evolution and diversification of diet in elapids

Kgaditse, Mimmie Mamafolo January 2016 (has links)
A dissertation submitted to the School of Animal, Plant and Environmental Sciences, Faculty of Science, University of the Witwatersrand, Johannesburg, South Africa in fulfilment of the requirements of the degree of Masters of Science. Johannesburg, South Africa. July, 2016. / A central goal in macroecology is understanding the factors that have shaped broad-scale patterns among extant natural communities. Diet is widely cited as a key factor involved in shaping snake diversification. Amongst serpents, the adaptive radiation of elapids is unparalleled in terms of their sheer global distribution. My study was aimed at evaluating the variation in diet and how trends evolved throughout the radiation of the elapids. Based on the published natural history data of 303 elapid species, a cluster analysis revealed seven groups of species within which diet types were similar. The broad diet clusters included snake consumption, feeding on fish, ectotherms, endotherms, lizards, a generalist diet and lastly, a terrestrial invertebrate group that was the least prevalent diet type. Maximum Parsimony, Maximum Likelihood and Stochastic Character Mapping were used to trace the ancestral dietary condition in the Elapidae. Reconstructions demonstrated that starting from an ophiophagous ancestor, elapids still largely retain their early feeding habits. Despite the emergence of novel feeding patterns in the group, the predominantly conservative diet patterns suggest that niche conservatism has shaped elapid foraging dynamics. Members of the lineage characteristically feed on elongate ectothermic prey (e.g., squamates, caecilians, eels, earthworms) possibly owing to morphologically-mediated gape constraints. Phylogenetically corrected comparative methods were used to assess the influence of differences in body size, lifestyle and global scale spatial distribution of diet evolution. While lifestyle and distribution considerably influenced how diet patterns evolved, body size was not a significant determinant of the prey types taken. The lack of body size-diet association may be because larger-bodied elapids also opportunistically supplement their diet with smaller prey items. Overall, the findings indicate that recent ecological factors (e.g., lifestyle) coupled with long established factors (phylogeny, biogeography) have shaped elapid natural history patterns. This study is the first of its kind to offer a family-level, phylogenetically-based analysis on the evolutionary and contemporary feeding dynamics of the world’s most widespread snake family. / LG2017
76

You Are Who You Eat With: Barriers to Adopting Animal-Free Diets

Franko, Emily January 2017 (has links)
Thesis advisor: Juliet Schor / This study investigates the barriers to adopting vegetarian and vegan diets. Why do people who try to adopt these diets fail to maintain them? Why do people who identify as vegetarian or vegan allow exceptions in their diets? This study used a series of intensive interviews and a survey to answer these research questions. Interviews and survey responses revealed the following barriers to maintaining vegetarianism/veganism: social barriers, a lack of vegetarian/vegan options, a loss of a “black-and-white” perspective on diet, nutritional barriers, personal cravings, time barriers, and a tendency to subscribe to gendered meanings of meat eating. Social barriers were the most salient challenges for study participants. Participants indicated that they commonly encountered several types of social barriers while attempting to maintain vegetarian/vegan diets. This study concluded that cultural norms must change in order for people to find vegetarian/vegan diets more viable. Most significantly, this study found that having a supportive social network of people who adhere to a similar diet is extremely important for people as they try to maintain vegetarianism/veganism. / Thesis (BA) — Boston College, 2017. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Departmental Honors. / Discipline: Sociology.
77

Energy expenditure and dietary intake of Hong Kong elite athletes. / Energy balance and dietary intake of Hong Kong elite athletes

January 1996 (has links)
Mimi Yuk-Mei Yeung. / Varying title: Energy balance and dietary intake of Hong Kong elite athletes. / Year shown on spine: 1997. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 132-148). / Chapter CHAPTER 1 --- INTRODUCTION AND AIMS OF THE STUDY --- p.1 / Chapter 1.1 --- Sports Development in Hong Kong --- p.1 / Chapter 1.2 --- Hong Kong Athletes Performance and Achievement --- p.1 / Chapter 1.3 --- Nutrition and Sport Performance --- p.2 / Chapter 1.4 --- Aims of the Study --- p.2 / Chapter CHAPTER 2 --- NUTRITION NEEDS OF THE ATHLETES --- p.4 / Chapter 2.1 --- Energy Needs of Elite Athletes --- p.4 / Chapter 2.1.1 --- Components of Energy Expenditure in Athletes --- p.4 / Chapter 2.1.2 --- Sex Differences in Energy Expenditure --- p.6 / Chapter 2.1.3 --- Indicators for Body Energy Stores --- p.7 / Chapter 2.2 --- Nutrient Requirements in Sports --- p.8 / Chapter 2.2.1 --- Carbohydrate --- p.8 / Chapter 2.2.2 --- Protein --- p.13 / Chapter 2.2.3 --- Fat --- p.14 / Chapter 2.2.4 --- Vitamins & Minerals --- p.15 / Chapter 2.2.5 --- Alcohol and Caffeine --- p.17 / Chapter 2.3 --- The Optimal Training Diet for Sports --- p.18 / Chapter 2.3.1 --- Training Diet for Optimizing Performance --- p.18 / Chapter 2.3.2 --- Review of Dietary Studies in Athletes --- p.18 / Chapter 2.3.3 --- Sex Differences in Dietary Intakes of Athletes --- p.20 / Chapter CHAPTER 3 --- NUTRITIONAL EVALUATION OF ELITE ATHLETES --- p.23 / Chapter 3.1 --- Evaluation of Activity Energy --- p.23 / Chapter 3.1.1 --- Factorial Method --- p.23 / Chapter 3.1.2 --- Direct and Indirect Calorimetry --- p.24 / Chapter 3.1.3 --- Doubly labeled Water --- p.25 / Chapter 3.1.4 --- Heart Rate Method --- p.25 / Chapter 3.2 --- Evaluation of Dietary Intake --- p.27 / Chapter 3.2.1 --- Dietary Assessment --- p.27 / Chapter 3.3 --- A review on Adopted Methods --- p.28 / Chapter 3.3.1 --- FLEX-HR Minute-by-minute Heart Rate Method --- p.28 / Chapter 3.3.2 --- Dietary Assessment Methods Adopted in the Present Study --- p.30 / Chapter 3.3.3 --- Food Composition Tables & Calculation of Nutrient Intake --- p.31 / Chapter 3.3.4 --- The Importance of Anthropometric Measurements --- p.30 / Chapter CHAPTER 4 --- "SUBJECTS, MATERIALS AND METHODS" --- p.38 / Chapter 4.1 --- Subjects --- p.38 / Chapter 4.2 --- Anthropometric Measurements --- p.38 / Chapter 4.3 --- Statistical Analysis --- p.39 / Chapter 4.4 --- Energy Assessment --- p.39 / Chapter 4.4.1 --- Subject Calibration --- p.39 / Chapter 4.4.2 --- "Respiratory Gas, Heart Rate Measurement and Analysis" --- p.40 / Chapter 4.4.3 --- Heart Rate and Regression Formula --- p.42 / Chapter 4.4.4 --- Minute-by-minute Heart Rate Recording --- p.43 / Chapter 4.4.5 --- Activity Record --- p.44 / Chapter 4.5 --- Dietary Assessment --- p.44 / Chapter 4.5.1 --- 3days 24-Hour Recall --- p.44 / Chapter 4.5.2 --- Estimation of Quantity of Food --- p.45 / Chapter 4.5.3 --- Nutrient Analysis --- p.45 / Chapter CHAPTER 5 --- RESULTS --- p.68 / Chapter 5.1 --- Anthropometric Changes in Athletes --- p.68 / Chapter 5.2 --- Individual Calibration Curve of Athletes --- p.68 / Chapter 5.3 --- Exercise Energy Expenditure of Athletes --- p.68 / Chapter 5.4 --- Total Daily Energy Expenditure of Athletes --- p.71 / Chapter 5.5 --- Dietary Intake of Athletes --- p.72 / Chapter 5.5.1 --- Energy Intake of Athletes --- p.72 / Chapter 5.5.2 --- Carbohydrate Intake of Athletes --- p.73 / Chapter 5.5.3 --- Nutrient Intake of Athletes --- p.74 / Chapter 5.5.4 --- Food Choices of Athletes --- p.76 / Chapter 5.6 --- Observations in Energy Balance in Athletes --- p.76 / Chapter CHAPTER 6 --- DISCUSSION --- p.116 / Chapter 6.1 --- Reliability of Energy Expenditure and Dietary Measurement --- p.116 / Chapter 6.1.1 --- Application of the FLEX-HR --- p.116 / Chapter 6.1.2 --- Application of the Polar Sport Tester PE3000 Heart Rate Monitor --- p.117 / Chapter 6.1.3 --- Reliability of Dietary Assessment for Energy and Carbohydrate Intake --- p.118 / Chapter 6.2 --- Energy Expenditure in Training / Exercise Days in Athletes --- p.118 / Chapter 6.3 --- Energy Intake and Energy Expenditure in Athletes --- p.121 / Chapter 6.4 --- Nutrient and Food Intake of the Athletes --- p.123 / Chapter 6.4.1 --- Energy Intake of Athletes --- p.123 / Chapter 6.4.2 --- Nutrient intake of Athletes --- p.124 / Chapter 6.4.3 --- Food Choices of Athletes --- p.128 / Chapter 6.5 --- Conclusions --- p.129 / Chapter 6.6 --- Recommendations --- p.129 / Chapter 6.7 --- A Need for Further Studies --- p.130 / References --- p.132 / List of Figures --- p.xi / List of Tables --- p.xiii / Appendix I Schofield equation for Basal Metabolic Rate --- p.149 / Appendix II Exercise Testing Protocols in Athletes --- p.150 / "Appendix III Computer print out of HR, VO2, and Energy Expenditure" --- p.151 / Appendix IV Form for Calibration Test Information --- p.152 / Appendix V Heart Rate Curve --- p.153 / Appendix VI Heart Rate and Energy Data Sheet --- p.154 / Appendix VII Heart Rate and Energy Curve --- p.155 / Appendix VIII Activity Record Sheet --- p.156 / Appendix IX Diet Record Sheet --- p.157
78

Diet and dialysis in acute renal shutdown

Albrecht, Ruby Jean January 2010 (has links)
Digitized by Kansas Correctional Industries
79

Spontaneous hypoglycemia : its etiology, diagnosis and dietary treatment

Harrison, Glenna D. January 2010 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
80

Effect of Voluntary Exercise and Diet on the Unfolded Protein Response in the Brain of Mice

Kim, Yu Ho 01 December 2011 (has links)
The Endoplasmic Reticulum (ER) is a net-like intracellular organelle where protein is folded, matures, and is transported. When cellular stressful circumstances affect the ER, unfolded proteins are stacked in the ER lumen. This cellular stress is called ER stress. To defeat ER stress, cells have a defensive mechanism called the Unfolded Protein Response (UPR). Many chronic diseases such as obesity and type 2 diabetes or neurodegenerative disease such as Alzheimer’s disease have recently been linked to ER stress. Exercise has a significant effect on ameliorating the development of these chronic diseases or neurodegenerative diseases. However, no studies have assessed the effect of exercise on UPR activity in the brain. So this study was mainly focused on identifying how voluntary running wheel exercise affects the UPR in the brain of C57BL/6 mice exposed to a variety of dietary conditions of differing levels of dietary fat and different periods of feeding. As an exercise protocol, access to a voluntary running wheel for 3 weeks was used and running mice were grouped depending on their level of running activity. Using real-time PCR and western blotting, UPR-related gene/protein expression (XBP1, ATF6, eIF2α, and GRP78) was assessed in different brain regions. Exercise had a significant effect on up-regulating UPR activity in the brain of mice fed low fat diet (LFD) or high fat diet (HFD) for 3 weeks or 3 months. These effects were time and brain region dependent. However, the effect of exercise on up-regulating UPR disappeared in mice fed very high fat diet (VHFD) for 4 months. In addition to assessing UPR activity, the possibility that exercise-induced UPR activation was associated with activation of apoptosis was investigated. Apoptotic signaling was not affected by exercise. Trophic factors are activated by exercise and are known to be linked to UPR activity. The possibility that IGF-1, one such trophic factor, was responsible for exercise-induced UPR up-regulation without activating apoptosis was studied. The results showed that IGF-1 was not responsible for exercise-related activation of the UPR in the brain. The chemical chaperone 4-phenylbutyric acid (PBA) was given to mice to reduce ER stress and the effect of exercise on the UPR of the brain was studied. PBA had a tendency to lower ER stress in the hypothalamus. In this condition, exercise had a significant effect to decrease UPR activity. In conclusion, voluntary exercise activates the UPR in several brain regions of mice exposed to high-fat diet for up-to 3 months without activating apoptotic signaling. Only long-term exposure to dietary fat increased the brain UPR. It is possible that this exercise-induced UPR activation without apoptosis may contribute to the protective effect of exercise on brain health. (134 pages)

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