The purpose of this study was to examine the vertical component of the American College of Sports Medicine (A.C.S.M.) Guidelines equation to predict the oxygen cost of grade running. The A.C.S.M. Guidelines equation is: VO$ sb2$(ml/kg.min) = 3.5 + 0.2 speed(m/min) + 0.9 (speed(m/min) * grade(frac)). Twenty-three female runners (20 to 33 years) participated in (1) a VO$ sb2$max test, (2) five 6 min running economy (RE) tests at 133 m/min, (3) five 6 min RE tests at 160 m/min, and (4) three 6 min RE tests at 186 m/min. The RE tests at 133 and 160 m/min were performed at the following grades: 0, 2.5, 5.0, 7.5, and 10.0%. The RE tests at 186 m/min were performed at 0, 2.5, and 5.0% grade. The RE tests were administered in random order. There was a linear relationship between VO$ sb2$ and horizontal running velocity with a slope of 0.20 ml/kg.m (r = 0.996; p $<$.01). There was a linear relationship between VO$ sb2$ and percent grade when running on a treadmill. The correlations for the regression equations at speeds of 133, 160, and 186 m/min were 0.90 (p $<$.01), 0.86 (p $<$.01), and 0.73 (p $<$.01), respectively. Inclusion of a grade component in the regression analysis equation increased the accuracy for predicting the VO$ sb2$ of grade running. VO$ sb2$ consumption for grade running can be predicted using the following equation: VO$ sb2$ (ml/kg.min) = 3.5 + 0.198(speed in m/min + 0.932 grade(%)) + 0.006(speed(m/min) * grade(%)). The new equation explained 99.5% of the variance (R$ sp2$) compared to the 78.0% of the variance (R$ sp2$) that was explained by the A.C.S.M. Guidelines equation.

The peripheral and central mechanisms mediating the modulatory effects of glucose and acute stress in rats were investigated using two versions of an appetitive win-stay task. Post-training injections of glucose, but not fructose, enhanced retention on the closed maze task. Acquisition of this task was found to be impaired by lesions of the fimbria-fornix (FF). Further experiments showed that while the celiac ganglion and the FF normally participate in suppressing the memory-enhancing effect of an acute stressor, neither structure is involved in mediating the effect of glucose on memory. Post-training injections of glucose, but not fructose, enhanced retention on the open maze task. Although acquisition of this task was not affected by FF lesions, both the celiac ganglion and the FF participate in mediating the memory-enhancing effect of glucose. Together, the results suggest that the peripheral and central mechanisms studied here are both substance- and task-specific. The modulatory effects of different types of stress, and the issue of whether task acquisition and memory modulation are anatomically distinct are discussed.

The studies included in this thesis had as aim to elucidate how individual differences in phonetic learning abilities might be related to differences in more general, psychoacoustic learning abilities, and in how they might be related to differences in brain function and brain morphology. / We tested and trained English speaking volunteers to perceive the Hindi dental-retroflex phonetic contrast. We found evidence suggesting that the ability to accurately perceive "difficult" non-native contrasts is not permanently lost during development. We also tested and trained subjects to perceive the difference between non-linguistic rapidly changing and steady-state tonal sounds, and found evidence supporting the hypothesis that successful phonetic learning is in part a function of a more general psychoacoustic ability to process rapidly changing sounds. / The aim of the second study was to determine how the pattern of brain activity may change as a result of training with non-native speech sounds, and in whether it is possible to differentiate "learners" from "non-learners" on the basis of neural activation patterns. Results of this functional magnetic resonance imaging (fMRI) investigation suggested that successful learning of a non-native contrast results in the recruitment of the same areas that are involved in the processing of native contrasts; but the degree of success in learning is accompanied by more efficient neural processing in classical frontal speech regions, while making greater processing demands in left parieto-temporal speech regions. / In the final study, we correlated phonetic learning measures with brain morphology throughout the whole brain volume. We found evidence for overall larger parietal volumes in the left relative to the right hemisphere, and for more white relative to gray matter in the left hemisphere in the learners and not in the nonlearners. This finding is consistent with findings by other investigators suggesting that left-hemispheric dominance for speech may be in part accounted for by hemispheric differences in white matter connectivity, which may allow faster intra- and inter-hemispheric neural transmission. This latter feature may be critical for the processing of consonant speech sounds, which depends on the ability to process sounds that change on the time scale of 30--50 milliseconds.

The reactions of the early and intermediate stages of protein glycation were studied using bovine serum albumin and hen egg white lysozyme as model proteins, and D-glucose and D-fructose as model reducing sugars. The reactions were studied under low moisture and limiting sugar conditions in the presence and absence of oxygen in a closed system. Several analytical methods, including the fluorescamine assay, total Maillard fluorescence and solubility measurement, size exclusion chromatography, and electrospray ionization mass spectrometry were used to follow the glycation reaction. The effect of glycation on the structure of proteins was also studied by electrospray ionization mass spectrometric peptide mapping. The results showed that under low moisture conditions, the initial rate of glucation was 5 to 6 times higher than the initial rate of fructation, both in the presence and in the absence of oxygen. The presence of oxygen in the reaction system induced selectivity of the glycation of the protein amino groups during the initial stages of the reaction, due to competition between glycation and glycoxidation. The reaction, however, occurred at a higher rate in the presence of oxygen than in its absence, especially during the latter stages of the reaction. The more reactive glycoxidation products, formed during the initial stages of the reaction also participated in the glycation reaction and increased the involvement of arginine residues in the glycation reaction. The glycation reaction also resulted in a heterogeneous mixture of protein glycoforms with varying degrees and extent of glycation. The heterogeneity of the glycated species was further complicated by the involvement of glycoxidation products in the glycation reaction, resulting in a distribution of different classes of glycoconjugates. Limited glycation improved protein solubility and increased solvent accessibility into the interior of the protein, thereby, increasing protein digestibility. Electrospr

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Anthropometric measures, physiological variables and skills tests were performed on subjects selected from the provincial KwaZulu Natai Junior Hockey teams in South Africa. The main purpose of this study was to establish a data base of norms for boy and girls in the UB, U14, U16, UI8 and the U2I age groups. The tests were done at the beginning and at the end of season. The anthropometric measures included height, weight, percentage body fat and lean body mass; physiological variables included sit-ups, push-ups, sit-and-reach (flexibility), broad jump, winder and bleep tests , and the skills tests comprised a wide range of ball skill tests. As expected, anthropometric changes were observed across the age groups, due to growth. Amongst the older age groups the girls had reached height and weight values comparable to elite female players , but only the boys in the U2I had reached their adult height and were slightly taller than the elite male players. There was no significant difference in the profile between the attack and defence players in the boys, but amongst the girls the defence players tended to be heavier and taller than the attack players. In the physiological and skills tests there was no difference between positional players. In the comparison between pre and end season to determine the effectiveness of the training programmes, there was a change in the anthropometric characteristics because of growth. However, the physiological and skill tests revealed no consistent pattern of improvement in the test results from pre season to end season. This study provides the first set of norms for male and female junior hockey players in South Africa. Further studies are required to expand upon and update the data in the current study. / Thesis (M.Med.Sc.)-University of Natal, Durban, 1997.

The experiments in this thesis examined the roles of stimulus configuration on conditioned cue preference (CCP) learning by asking what information is processed and by which neural substrates. Results from Experiments 1 and 2 showed that lesions of the lateral nucleus of the amygdala (LNA) but not of fimbria-fornix (FF) impaired CCP learning when the cues paired with food during training were distinct from those not paired with food in either of two different apparatuses. In Experiments 3 and 4 LNA lesions increased the size of the CCP when the cues paired with food and no food were ambiguous in two different apparatuses. Learning the ambiguous cue CCP required at least one session of unreinforced pre-exposure to the cues and was eliminated by FF lesions. In the last series of experiments, a latent learning effect of unreinforced pre-exposure on ambiguous cue CCP learning on the radial maze was found in normal animals that received at least 3 sessions of unreinforced pre-exposure. FF lesions made before, but not after, pre-exposure eliminated the latent learning effect. Hippocampus lesions made either before or after pre-exposure eliminated the CCP learning. Taken together, the results are consistent with the hypothesis that distinct cue CCP learning is based on conditioned approach responses to cues paired with food, mediated by a neural system that includes the LNA. The results also suggest that ambiguous cue CCP learning takes place in two phases. First spatial learning occurs during unreinforced pre-exposure, a process that requires an intact FF. Subsequently, information about the location of the reinforcer is added to the spatial information during the reinforced training trials by a process of "reconsolidation". An intact hippocampus is required for this process. The implications of these results and interpretations for latent learning and latent inhibition are considered.

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Controversy exists concerning the role that dopamine plays in analgesia. In the present studies, dopamine agonists produced analgesia, and D-amphetamine potentiated morphine analgesia, while treatment with 6-hydroxydopamine or mixed or selective D1 and D2 dopamine receptor antagonists attenuated or abolished morphine and D-amphetamine-induced analgesia, in the formalin test. Furthermore, microinjection of morphine into the ventral tegmental area (VTA) and ventral striatum produced analgesia, while intra-VTA microinjection of naloxone methylbromide antagonized the analgesia produced by systemic morphine, in the formalin test. In contrast, similar manipulations of dopamine had little or no effect in the tail flick test. Thus, dopamine appears to play a facilitatory role in formalin test analgesia, and there appear to be fundamental differences between the formalin and tail flick tests and parallels between the role of dopamine in the formalin test and in clinical pain, the vocalization after-discharge test and reward.