There is a global need for sustainable, renewable and clean energy sources. Microbial production of hydrogen from renewable carbon sources, biorefinery compounds such as succinic acid or from food and drinks industry waste meets all these criteria. Although it has been studied for several decades, there is still no large scale bio-hydrogen production because the rate and yield of hydrogen production are not high enough to render the process economical. The dependency of biological hydrogen production of incipient light energy is also an important factor affecting economics. In order to improve the prospects of biohydrogen as a renewable and sustainable energy alternative, the genetic and process engineering approaches should be helped and targeted by metabolic engineering tools such as metabolic flux balance analysis. The overall aim of this research was the development of computational metabolic flux balance analysis for the study of growth and hydrogen production in Rhodobacter sphaeroides. The research reported in this thesis had two approaches; experimental and computational. Batch culture experiments for growth and hydrogen production by Rhodobacter sphaeroides were performed with either malate or succinate as carbon source and with glutamate as the nitrogen source. Other conditions investigated included; i) aerobic and anaerobic growth, ii) light and dark fermentation for growth, and iii) continuous light and cycled light/dark conditions for hydrogen production. The best growth was obtained with succinate under anaerobic photoheterotrophic conditions with the maximum specific growth rate of 0.0467 h– 1, which was accompanied with the maximum specific hydrogen production rate of 1.249 mmol(gDW.h)– 1. The range of the photon flux used was 5.457 - 0.080 mmol(gDW.h)– 1. The metabolic flux balance model involved 218 reactions and 176 metabolites. As expected the optimised specific rates of growth and hydrogen production were higher than those of the experimental values. The best prediction was for hydrogen production on succinate with computed specific hydrogen production rates in the range of 2.314 - 1.322 mmol(gDW.h)– 1. Sensitivity analyses indicated that the specific growth rate was affected by the nitrogen source uptake rate under aerobic dark condition whereas the flux of protein formation had the largest effect on the specific growth rate under anaerobic light condition.

In North America ice hockey is considered to be the fastest of all teamsports with high demands on leg strength and power. These two factors are crucial for acceleration and the total speed performance during a hockeygame. Skating performance requires a muscle engagement which also occurs during the Y-Balance Test (YBT). Some of the most active muscles during ice skating are biceps femoris, tibialis anterior and vastus medialis , these muscles are also some of the most active muscles during the YBT. The similarities between those two activities enable a possible relationship between skating velocity and YBT. This study investigated the relationship between dynamic postural control and on ice performance which includes 52 meter forward skating. The purpose of this study was to see if there is a significant correlation between skating velocity and the performance on YBT. Methods: 7 male ice hockey players in ages between 18-19 years performed a 52 meter forward skating test and a test for evaluating their dynamic postural control. The method used for measuring the dynamic postural control was the YBT. Results: There was no significant correlation between the YBT longitudinal directions, the total score and 52 meter forward skating. The strongest association (0,570) was shown between the YBT anterior longitudinal direction and 52 meter forward skating. The total score on YBT did not show a significant correlation with 52 meter forward skating, with a correlationcoefficient of 0,251. Conclusion: Due to several management errors during the YBT the results showed no significance. We can not for certain say that there is no significant correlation due to for instance management errors and the deficiency pf power. Future studies are needed to determine if there is a significant correlation between skating velocity and the performance on YBT.

This paper aims to explain how the interplay between formal and informal institutions affects the potentially gendered outcomes of political reforms. The case of the Chilean parental leave reform of 2011 is used as an example of a political reform addressing gender equality. Within the framework of historical institutionalism analysis of formal and informal institutions are made separately to proceed to merge the two and discuss how they interact with each other and affect the outcomes of the reform. The formal institution is studied by analyzing the construction of the reform itself and the informal institutions are studied by analyzing interviews with parents making use of this reform.                       The results of this research show that both formal and informal institutions follow a historical pattern of social norms placing the responsibility of childcare on mothers. Formal institutions seems to follow a certain path dependency in the way they are created and informal institutions affect and counteract the small possibilities to change given by the formal institution. Possible indications of critical junctures challenging this path dependency were however found and show a potential period of significant adjustment in informal institutions and the reform might be seen as an example of change.

QC 20100707

Vertigo is the presenting symptom of some peripheral vestibular disorders, like Benign Positional Vertigo (BPV), Ménière's disease, and vestibular neuritis, and for many other clinical conditions as well. Some clinicians from the Christchurch Public Hospital suspect that there is a significant need to improve the diagnostic accuracy and overall management of patients presenting with complaints of "acute vertigo or dizziness", especially BPV and Ménière's disease. The final diagnosis of many such patients treated for these conditions in the past has been suspected to be somewhat incomplete or inappropriate. These patients were commonly referred to various other departments, where they underwent a number of investigations, particularly medical imaging [head CT (Computed Tomography) / MRI (Magnetic Resonance Imaging) scans, which were in many cases not necessary. Such delays in the process led to an extra or unnecessary burden on the limited health funds available to the hospital or to the patient. Another drawback was an elevated patient stress and anxiety as critical time was lost with the increased number of admissions, or in transferring the patient between various departments without any conclusive diagnosis and treatment. It was proposed to conduct a retrospective study on the accuracy of diagnosis of those patients admitted to Christchurch Public Hospital with complaints of acute vertigo, particularly for suspected peripheral vestibular disorders (mainly BPV and Ménière's disease) over the period of 2004-2005. Implementation of a more specific and detailed management approach at the level of the initial clinical examination or diagnostic investigations (specifically, by an early Otolaryngology/Audiology intervention) was planned for the year 2006. The two groups of patients (2004-2005 and 2006) were compared to verify the final achievements concerning the diagnostic accuracy and at various other levels with the newly implemented changes in 2006.

The aim of this research was to demonstrate the relationship between variations in summertime surface mass balance of the McMurdo Ice Shelf and atmospheric processes. The approach encompassed a broad range of techniques. An existing energy balance mass balance model was adapted to deal with debris-covered ice surfaces and modified to produce distributed output. Point based surface energy and mass balance for two key surfaces of the ice shelf were linked to different synoptic types that were identified using a manual synoptic classification. The distributed model was initialised with distributed parameters derived from satellite remote sensing and forced with data from a regional climate model. Patterns of summertime surface mass balance produced by the distributed model were assessed against stake measurements and with respect to atmospheric processes. During the summers of 2003-2004 and 2004-2005 an automatic weather station (AWS) was operated on bare and debris-covered ice surfaces of the McMurdo Ice shelf, Antarctica. Surface mass balance was calculated using the energy balance model driven by the data from the AWS and additional data from permanent climate stations. Net mass balance for the measurement period was reproduced reasonably well when validated against directly measured turbulent fluxes, stake measurements, and continuously measured surface height at the AWS. For the bare ice surface net radiation provided the major energy input for ablation, whereas sensible heat flux was a second heat source. Ablation was by both melt (70%) and sublimation (30%). At the debris-covered ice site investigated, it is inferred that the debris cover is sufficient to insulate the underlying ice from ablation. Synoptic weather situations were analysed based on AVHRR composite images and surface pressure charts. Three distinct synoptic situations were found to occur during the summers, these were defined as Type A, low pressure system residing in the Ross Sea Embayment; Type B, anticyclonic conditions across region; and Type C, a trough of low pressure extending into the Ross Sea Embayment. A dependence of surface energy fluxes and mass balance on synoptic situation was identified for the bare ice surface. The distributed model was found to produce spatial patterns of mass balance which compared well with stake measurements. Mass balance patterns show that the McMurdo Ice Shelf was generally ablating in the west, and accumulating in the east during summer. Areas of enhanced ablation were found which were likely to be caused by the surface conditions and topographic effects on the wind field. The mean summertime surface mass balance across the entire ice shelf for the 2003-2004 and 2004-2005 summers were –2.5 mm w.e. and –6.7 mm w.e. respectively. The differences between the two summers are inferred to be a result of more frequent type A conditions occurring during the summer of 2004-2005.

Thermoregulation is considered a top priority in neonatology due to the fact that relative to adults, neonates have a morphological susceptibility to excessive heat exchange with the environment, and exhibit limited physiological/behavioural responses to thermal strain. Consequently, the environmental conditions in which they are nursed must be tightly regulated to maintain body temperature stable. Neonatal intensive care units (NICU) use radiant warmers (RW) to thermally manage many newborns. However, recent evidence suggests that RW induce intermittent bouts of thermal strain that could adversely affect patients. This warrants further investigation of neonatal heat balance and the pertinent factors affecting it. Conducting an exhaustive audit of heat exchanges affecting the body during standard care under a RW could yield important information that would lead to the improvement of clinical practice in NICUs. The present thesis focuses on neonatal thermoregulatory responses, various body heat exchange mechanisms and processes during standard care under RW.

Background: Rugby injuries are a common phenomenon. The aim of medical professionals is to treat these injuries to the best of their abilities, and if possible, to help prevent their occurrence. Bahr and Holme (2003) argue that sports participation carries with it a risk of injury, with the even more weighty issue that it might later even lead to physical disability. Junge, Cheung, Edwards and Dvorak (2004) recommends the development and implementation of preventative interventions to reduce the rate and severity of injuries in Rugby Union. The Medical and Risk Management Committee of USA Rugby (2003) also reports that the key to preventing injuries in any sport is identifying and addressing the risk factor associated with it. Various studies have identified weakness in plyometric strength, proprioception arid balance as - of lower leg and ankle injuries (Margison, Rowlands, Gleeson arid Eston, 2005; Stasiwpoulos, 2004; Verhagen, Van der Beck, Twisk, Bahr and Mechelen, 2004; Baltaci & Kohl, 2003; Mlophy, Conaoly and Beynnon, 2003; Moss, 2002; Anderson). Aims: ThE aim of this study was to investigate the influence of proprioception, balance and plyometric strength on the occurrence of lower leg injuries in schoolboy rugby players. A further aim was to develop a preventative training programme to address these variables, should they prove to have an influence on lower leg injuries. The possible inclusion of these tests in talent identification test batteries will also be examined. Design: A prospective cohort study. Subjects: A group of 240 schoolboys in U/14, U/15, U/16 and U/18 age groups in two schools (Hoër Volkskool Potchefstroom ("Volkskool") and Potchefstroom Boys High School ("Boys High")) in the North West Province of South Africa was used as the test cohort. Method: At the beginning of the 2006 rugby season all players were tested for proprioception, balance and plyometric strength. These tests were conducted using a computerised tilt board for proprioceptive testing; Star Excursion Balance Test for Balance and an electronic timing mat for plyometric strength. During the season, weekly injury clinics were held at both schools to document all injuries that occurred following the preceding weekend's matches. A statistical analysis was done on all the data collected from the test batteries and injury clinics. Descriptive statistics (means, standard deviation, minimum and maximum) were used as well as practical significant differences (d-values) (Cohen, 1988). The ratios for left and right leg plyometric strength to bilateral plyometric strength (L+R/Bil) and individual left and right leg plyometric strength to bilateral plyometric strength (L/Bil and R/Bil) were also calculated. Results: A profile of proprioception, balance and plyometric strength was compiled for schoolboy rugby players using the test data The U/18 players generally bad the best test results of all the age groups, outperforming U/14, U/15 and U/16 players with most tests. U/15 players outperformed both U/14 and U/16 players. Backline players performed better than loose forwards and forwards in plyometric tests in most age groups. Loose-forwards also outperformed tight-forwards with plyometrics at most age groups. At U/15 and U/16 level, tight-forwards slightly outperformed loose-forwards with Star Excursion Balance Tests. Generally, A-teams performed better than B-teams with all the tests except L+R/Bil; L/Bil and R/BiI. The difference between the teams, however, only had a small to medium effect and cannot be considered practically significant. At U/14 and U/15 levels, there were more practically significant differences between the A- and B-teams, with A-teams outperforming B-teams. The tests could have some value for talent identification at this age level. A rugby epidemiological study was done on the data collected in the weekly injury clinics. This study recorded 54 injuries at the two schools involved during the 2006 season from April to July. Two hundred and forty players were involved in 10890 hours of play. Eight thousand nine hundred and ten of these player hours were practices and 1980 were match hours. These injuries occurred at a prevalence rate of 4.96/1000 player hours. Match injuries accounted for 77.78% of all injuries with training sessions resulting in the remaining 22.22% of injuries, with a match injury rate of 1 injury per individual player every 3.14 matches. U/14 players showed an overall match injury rate of 11.11/1000 match hours. U/15 players showed a rate of 2.47/1000 match hours. The low rate may be attributed to underreporting of injuries by the U/15 players. U/16 players showed a late of 22.33/1000 hours, while U/18 players showed an exceptionally high rate of 45/1000 match hours. The tackle situation was responsible for the highest percentage of injuries (57.14%). Boys High presented with more injuries (57.4%) than Volkskool at a higher prevalence rate (5.60/1000 player hours). In a positional group comparison, backline players presented with 51.85% of injuries. Since backline players only present 46.7% of players in a team, this shows that backline players have a higher risk of injury. A-team players presented with 66.6% of injuries at a prevalence rate of 6.37/1000 player hours. B-team players had an injury rate of 3.43/1000 player hours. The test values for the players suffering lower leg injuries were compared to those for uninjured players. There were eight players with nine lower leg injuries: one player had injuries of both legs. Six of the injuries were intrinsic of nature and two players had extrinsic injuries. Test values for all five tested players with intrinsic injuries were weaker by a high practically significant margin for the L+R/Bil ratio. Conclusion: L+R/Bil proved to be the test result with the most influence on the occurrence of intrinsic lower leg injuries. When the individual test results for the players with intrinsic injuries are compared to the percentiles for all players, it becomes visible that the injured players fall in the 20th percentile for both L+R/Bil and Injured leg/Bil ratios. These 20th percentile values could thus be used as a standard for determining the possible occurrence of intrinsic lower leg injuries. These 20th percentile values are 1.012 for R+L/Bil ratios; 0.483 for L/Bil ratios and 0.492 for R/Bil ratios. This study shows that plyometric ratios for L+R/Bii, L/Bil and R/Bil have an influence on lower leg injuries in schoolboy rugby players. Proprioception and balance did not have any practically significant effects on the occurrence of these injuries. A preventative training programme was also designed following a study of the literature, combined with these results. The tests could also possibly be integrated in talent identification test batteries at U/14 and U/15 level. / Thesis (M.Ed.)--North-West University, Potchefstroom Campus, 2007

Background: Daily nutrient/energy intakes are typically evaluated as a total 24-hour intake rather than as the amounts consumed per eating opportunity. Evidence suggests that smaller, frequent meals containing persistent levels of energy and protein may be more beneficial for achieving a lower body fat and higher fat-free mass than equal intakes consumed in larger and less frequent amounts. This may be due to a better-maintained energy balance (EB) that is achieved with smaller and more frequent intakes. Objective: The objective of this study was to determine the relationship between hourly EB and protein intake with body composition. Methods: Using a software program that provides hourly and 24-hour energy and nutrient intakes and hourly energy expenditures, a secondary analysis of previously collected 3-day food diaries was used to examine the relationship between hourly EB and body composition. The food and activity diaries provided information on time of food/beverage consumption and hourly energy expenditure, enabling an hourly analysis of EB. Body composition, including fat mass, fat-free mass, and bone density were examined via dual-energy x-ray absorptiometry. SPSS was used for statistical analysis, and included descriptive statistics, correlational analyses, t-tests, and regression analyses. Results: Existing data from elite female gymnasts (N=40) were assessed using an IRB-approved protocol. Higher protein consumption was significantly associated with lower bone mineral density (BMD) in the gymnasts at the arms (r= -0.535; p< 0.001), legs (r= 0.0523; p= 0.001), trunk(r= -0.517; p=0.001), spine (r= -0.472; p=0.002), and pelvis (r= -0.539; p< 0.001). Other dietary factors assessing energy and protein intakes were not significantly associated with body composition. The assessed gymnasts spent the majority of the day in hourly energy balance deficits exceeding -400 kcal. A t-test comparing subjects with higher (n=22) vs. lower (n=18) fat-free mass (FFM), using the statistical mean as the cut point, found that higher protein intakes were significantly associated with lower FFM (p=.007). Subjects with more hours spent in an EB surplus had significantly higher FFM/kg (p=.008) and lower body fat % (p=.008). Conclusion: These findings suggest that higher protein intakes may compromise BMD, a finding likely exacerbated by the long periods of time spent in EB deficits. More hours in an EB surplus was associated with positive outcomes, including higher FFM/kg and lower body fat percent. These data suggest that higher protein intakes may be consumed by gymnasts with the greatest EB deficits, perhaps as a way of minimizing (unsuccessfully) weight and fat-mass. As virtually all hours of the assessed groups were in an EB deficit, it is possible that consumed protein was used to satisfy energy needs rather than being used anabolically to support or enlarge the muscle mass. Future studies should consider addressing this issue, perhaps by assessing more heterogeneous groups where at least a proportion of the population sustains a reasonably good EB during the assessment period.

Title: Within-Day Energy Balance and Protein Intake Affect Body Composition in Physically Active Young Adult Females Background: Past studies suggest that individuals who eat smaller, more frequent meals are at a metabolic advantage when compared to those who eat larger, less frequent isocaloric meals. Studies also suggest that consumption of small amounts (~ 20 to 30 g) of protein evenly distributed during the day, may be a superior strategy for satisfying the protein requirement and improving muscle protein synthesis. It was, therefore, the purpose of this study was to assess the relationship between body composition and the distributed consumption of energy and protein in physically active young adult females. Methods: Using an IRB approved protocol, physically active female volunteers were measured for height using a standard wall mount stadiometer; body composition and weight were measured using a multi-current 8-mode segmental bioelectrical impedance device (Tanita, Arlington Heights, Illinois USA, Model BC-418). The volunteers kept a food and activity journal for one day, which was assessed to determine hourly energy balance and hourly protein intake. Exertion was assessed using a relative intensity activity MET value scale that produces multiples of resting energy expenditure, which was predicted using the Harris-Benedict equation. Results: The 28 females who volunteered for this study ranged in age from 19-24 years. Significant inverse associations were found between protein (grams/kg) consumption and fat mass (r=-0.42; p=0.026); and FFM and the ratio of protein to energy balance at 4pm (r=-0.376; p=0.049). There was a significant positive association between FFM and the ratio of protein to energy balance at 12pm (r=0.390; p=0.040) and 9pm (r= 0.379; p=0.047). There was also a significant positive association between the ratio of FFM to height and the ratio of protein to energy balance at 12 pm (r=0.423; p=0.025). There was a significant association between highest daily peak energy balance and FFM to height ratio (r=0.402; p=0.034). Regression analysis determined that independent EB and protein variables could be used to predict the dependent variable FFM to Height ratio (r=.727; p=0.019). Conclusions: These findings demonstrate a significant positive association between highest daily EB and FFM to height ratio. The results also suggest that higher protein consumption per kg is inversely associated with fat mass. Similarly, when protein is consumed when in ±400 kcal energy balance, is associated with higher FFM. Additionally, energy balance and protein variables can be used to predict FFM to height ratio using a regression equation that accounts for 52.9% of variance. These data indicate that subjects spent far more hours in an energy balance deficit than surplus, making it difficult to assess the impact of protein intake distribution on body composition. It does appear that, from a relatively small subsample (n=28) who did achieve a positive within-day energy balance and adequate protein intake, consumption of protein while in good energy balance may help physically active adult females achieve a body composition that is low in fat mass and high in lean muscle mass.