Background: Dietary salt intake in the South African population exceeds the physiological need. Excessive salt intake is associated with elevated blood pressure levels which may lead to hypertension and cardiovascular accidents. A lifestyle modification such as dietary salt restriction is an inexpensive, effective disease prevention option. Objective: The overall main objectives of this investigation was to: 1) compare salt intake, estimated from a short salt frequency intake questionnaire, with the 24-hour urinary salt excretion and blood pressure of young normotensive healthy white and black South Africans; and 2) compare 24-hour salt excretion and 24-hour blood pressure profiles of normotensive white and black individuals in terms of their knowledge, attitude and behaviour towards dietary salt intake. Study design: The study design was cross-sectional and nested in the baseline phase of the African Prospective Study on the Early Detection and Identification of Cardiovascular Disease and Hypertension in South Africa (African-PREDICT) study. Methods: Multiple methods of data collection were used including anthropometry, biochemical analyses, dietary intakes and cardiovascular measurements. Participants in the study completed the short salt frequency intake questionnaire, describing and quantifying habitual salt intake, and a questionnaire describing knowledge, attitude and behaviour regarding salt intake. Responses to the questionnaires were compared with actual salt intakes estimated from a single 24-hour urine sample and with the 24-hour blood pressure measurements. Results: There was no significant correlation between salt intake based on the questionnaire and 24-h urinary excretion in the white (r=0.07; p=0.40) and black (r=-0.53; p=0.56) participants before and after adjustment for covariates. Estimated salt intake from the questionnaire significantly correlated with systolic blood pressure in white participants (r=0.22, p=0.005) before adjustment for covariates and was no longer significant after adjustment. None of the correlations (unadjusted or adjusted) were significant for the black participants (all p>0.05). The Bland-Altman plots for salt intake showed that the mean difference between the methods used to determine salt intake for the white group is 0.5 g/day, and for the black group is -1.9 g/day. The urinary salt excretion may estimate salt intake to be 9.6 g/day above or 11.1 g/day below the questionnaire’s estimation in the white, and 10.8 g/day above and 18.4 g/day below in the black groups. The level of agreement (Cohen’s Kappa analyses) between the salt frequency questionnaire and the 24-hour urinary salt excretion were determined by categorising the participants in groups who meet the target of <5 grams salt per day or do not. The value of Kappa for the white participants was 0.17 (slight agreement) and for the black participant it was -0.06 (no agreement). In the white participants were a significant increase in both SBP and DBP with increasing tertiles of salt intake according to the questionnaire (p<0.006 and p<0.02 respectively). In the black participants there were no significant difference in BP levels (all p>0.05). The five foods/food groups that contributed most to dietary salt intake in both ethnic groups were discretionary salt, bread, gravy made with stock or gravy powder, soup and biltong. There were no differences in the BP levels between those who answered questions about their knowledge and attitude towards salt intake in both ethnic groups (all p>0.05). Also, there were no differences in their urinary salt excretion (all p>0.05). Only certain behaviours mentioned in the questionnaire were reflected in the salt intake levels and blood pressure. Conclusions: The short salt frequency intake questionnaire can be used to identify food items that contribute to total salt intake. However, the questionnaire considerably underestimates the dietary salt intake. The application of this questionnaire may be helpful in epidemiological studies that evaluate foods which contribute to the total salt intake in order to monitor the average salt intake of a population and to assess the proportion of the population that does not meet the target of less than 5 grams of salt intake per day. It cannot, however, be used to assess the salt intake of an individual. The knowledge, attitude and behaviour of women and men of both ethnic groups are poorly reflected in their actual salt intake and blood pressure, especially among the black participants. The majority of the participants in both ethnic groups consume dietary salt in much higher quantities than the recommended less than 5 grams per day. The current public awareness campaign to decrease salt intake to the target level of less than 5 grams per day by the South African National Department of Health and the Heart and Stroke Foundation is commendable. / MSc (Nutrition), North-West University, Potchefstroom Campus, 2015

Background: Child sexual abuse is a problem that manifests in all spheres of our society, a social problem that often crosses the desk of a social worker rendering services to children and families. The researcher can still remember how daunting her first experience was when she dealt with an allegation of child sexual abuse. Now, in hindsight she believes that if she had more in-depth knowledge when dealing with children who has been sexually abused and their disclosure thereof, it would have made the world of difference to her and the clients that she was rendering services to. Objectives: The primary aim of the study was to investigate the level of knowledge that the social workers of Child Welfare Tshwane currently have when dealing with a disclosure of sexual abuse during the intake interview. The findings will provide guidelines to Child Welfare Tshwane regarding the required level of knowledge of social workers during the intake interview when dealing with a sexual abuse disclosure. Method: The study was conducted through a questionnaire that was composed using information gathered during a literature study. Social workers employed by Child Welfare Tshwane completed the questionnaire in order to shed light on their knowledge base with regard to child sexual abuse and the disclosure thereof. Results: Through the study it was evident that the knowledge base of social workers from Child Welfare Tshwane, dealing with child sexual abuse, is variable and lacks continuity. / MSW (Forensic Practice), North-West University, Potchefstroom Campus, 2015

Doctor of Philosophy / Department of Human Nutrition / Valentina M. Remig / The frequency of dietary supplement use has increased in recent years, especially among older adults. National studies estimated 60-65% of older adults were using at least one dietary supplement, typically a multi-vitamin, multi-mineral (MVMM) supplement. Dietary supplement use has been reported to improve the micronutrient intakes of older adults. The current research study focused on the use of dietary supplements, dietary intakes, and impact of vitamin/mineral (VM) supplements on the nutrient intakes of older Kansans. Volunteer subjects, 60+ years of age, were recruited from 35 senior centers across Kansas. Subjects completed a questionnaire asking for demographic information, current health status, and dietary supplement use. Dietary supplement use was verified for 319 subjects. Two subsequent 24-hour diet recalls were completed by 312 subjects. The sample population was primarily white, non-Hispanic females. Nearly 86% of participants used at least one dietary supplement; most commonly MVMM, calcium, vitamin D, and fish oil. Dietary intake analyses compared intakes of dietary supplement (DS) users to non-dietary supplement (NDS) users. DS subjects consumed significantly higher dietary intakes of carbohydrate, fiber, vitamin A, and zinc than NDS subjects. The NDS group consumed undesirably higher intakes of total fat, saturated fat, and sodium. These results support previous findings that DS users consume healthier diets. The impact of VM supplement use on micronutrient intake compared only the intakes of subjects using VM supplements (n=263) to the Dietary Reference Intakes (DRI). Subjects were most likely to have inadequate dietary intakes of vitamin D, calcium, vitamin E, and magnesium. All micronutrient intakes were improved with the inclusion of VM supplements; most improved were vitamin E, folic acid, vitamin D, vitamin B6, and calcium. Despite supplementation, nearly half of subjects still exhibited low intakes of vitamin D, calcium, and magnesium. Supplementation did not consistently exceed the Tolerable Upper Limit established by the DRIs for most nutrients. In conclusion, dietary supplement use was very common in the sample population, DS subjects had generally healthier diets, and VM supplement use improved micronutrient intake without contributing to concern for toxicity.

Depuis une vingtaine d’années, l’engouement pour les propulsions hydrojets n’a fait que croître et elles s’imposent aujourd’hui comme la propulsion marine incontournable pour les hautes vitesses. Dans un même temps, un outil permettant un gain considérable de temps et d’argent s’est lui aussi développé considérablement. En effet, la CFD (Computational Fluid Dynamics) est devenue une pratique courante lorsqu’il s’agit de prévoir le comportement d’un écoulement sans avoir à passer par un modèle réel. Elle sera utilisée tout au long du projet pour simuler le flux au travers de la propulsion. Le design d’une entrée d’eau est capital : une entrée d’eau mal conçue engendrera des zones de cavitation, de la recirculation sur la lèvre ou la rampe, des pertes importantes et un champ de vitesse non uniforme à la face de la pompe. Il en résultera une diminution du rendement de l’entrée, mais aussi une diminution du rendement de la pompe, puisqu’optmisée pour un flux uniforme. L’objectif de ce projet sera d’optimiser l’entrée d’eau pour augmenter le rendement global de la propulsion et ainsi réduire la consommation d’essence de 6 % sur un cycle donné. Actuellement, les conduites d’entrées sont conçues pour optimiser une vitesse de croisière moyenne. Dans ce projet, le but sera d’éviter d’avoir un compromis à faire entre les basses vitesses, la vitesse de croisière et la vitesse de pointe, et d’optimiser la géométrie de l’entrée pour une large plage de fonctionnement. Cela passe par une géométrie variable et donc un mécanisme asservi. Afin de concevoir un tel système, il sera nécessaire de trouver les géométries optimales pour les différents régimes de fonctionnement. Une étude CFD 2D paramétrable permettra de trouver les lignes directrices de ces géométries. Un modèle 3D devra ensuite être validé, puis utilisé pour pouvoir affiner les géométries optimales. Un système sera alors conçu puis testé sur le modèle CFD. Des tests expérimentaux viendront finaliser l’étude.

Résumé : Introduction: Chez les aînés, la perte de dents et les difficultés masticatoires peuvent entraîner une réduction de la qualité de la diète et une perte de poids. Objectifs: Dans une population âgée vivant à domicile, nous voulons déterminer la cohérence interne et la validité de critère d’un questionnaire sur la perception de l’efficacité masticatoire. Nous désirons aussi vérifier la relation entre l’efficacité masticatoire et l’alimentation, notamment l’apport protéinique, l’apport en vitamine C et folate ainsi que la consommation de fruits et légumes. Méthodologie: Une analyse secondaire des données recueillies à l’entrée de l’Étude longitudinale québécoise sur la nutrition comme déterminant d’un vieillissement réussi (NuAge) a été réalisée. NuAge est une étude observationnelle (2003-2008) de 1793 hommes et femmes âgés de 68-82 ans, généralement en bonne santé lors du recrutement. L'échantillon total (n=1789) a été utilisé pour déterminer la cohérence interne puis un sous-échantillon (n=94), dont les participants ont passé un test clinique de l'efficacité masticatoire, a été utilisé pour mesurer la validité de critère du questionnaire. Le questionnaire contient 7 questions tirées du Oral Health Impact Profile (échelle de Likert, score total= 28 points). Le test clinique (Swallowing Threshold Test Index, score 0 à 100%) a été utilisé pour mesurer l'efficacité masticatoire. Pour ces deux instruments, un score élevé indique une bonne efficacité masticatoire (perçue ou mesurée). Les apports habituels de protéines, de vitamine C, de folate et de fruits/légumes ont été calculés à partir de 3 rappels alimentaires de 24 heures non-consécutifs. Résultats: Les scores moyens obtenus au questionnaire sont élevés [H:25.3;IC(24.7-25.9); F:24.3;IC(23.7-25.0)], indiquant une bonne efficacité masticatoire perçue. Les participants du sous-échantillon (50H, 63F) ont des scores moyens au test masticatoire de 60.8% [H:IC(57.3-64.2)] et de 61.2% [F:IC(57.7-64.7)]. La cohérence interne du questionnaire est considérée «satisfaisante» (Alpha de Cronbach= 0.803). Aucune relation significative n’a été observée entre l'efficacité masticatoire perçue et mesurée (r= -0.14; p= 0.22). Une prévalence élevée (78,9%) d'apports alimentaires insuffisants en fruits et en légumes (<7 portions/jour), se traduit par des niveaux élevés (53,9%) d'apports insuffisants en folate chez les femmes (<320μg/j). Après ajustement pour l'âge, le sexe, la scolarité et le revenu, le score d'efficacité masticatoire n'est pas significativement associé aux apports alimentaires. Conclusion: Malgré la bonne cohérence interne du questionnaire et la validité reconnue du test, il semble que les résultats de l'efficacité masticatoire perçue ne réflètent pas la «vraie» efficacité masticatoire mesurée avec le test. De plus, on n'observe aucune relation significative entre l'efficacité masticatoire et les apports alimentaires. Des tests masticatoires adaptés aux aînés et intégrant les impacts sur la déglutition et sur la digestion seraient à développer. // Abstract : Introduction: Among seniors, loss of teeth and chewing difficulties can cause diet's quality reduction and weight loss. Objectives: Among generally healthy seniors, we want to determine internal consistency and criterion validity of a questionnaire assessing the perception of masticatory efficiency. We also want to assess the relationship between masticatory efficiency and food intake (protein, Vitamine C, folic acid and fruits/vegetables). Methodology: This is a secondary cross-sectional analysis of the baseline data from the NuAge Study (Québec Longitudinal Study on Nutrition and Successful Aging). NuAge is a 5-year (2003-2008) observational study of 1793 men and women aged 68-82 years in good general health at recruitment. The total sample (n=1789) was used to determine internal consistency of the questionnaire. A subsample (n=94) of the cohort who underwent a clinical test measuring directly masticatory efficiency was used to determine criterion validity of the questionnaire. The questionnaire was a subset of the Oral Health Impact Profile (Likert-scale, total score= 28 points). Assessment of masticatory efficiency was carried out using a clinical test measuring the ability to chew a raw carrot, (Swallowing Threshold Test Index, score from 0 to 100%). For both measures (perceived or measured) a higher score indicates a better masticatory efficiency. Usual protein, Vitamin C, folic acid and fruits/vegetables intakes are calculated from 3 nonconsecutive 24h dietary recalls. Results: Internal consistency of the questionnaire was deemed «satisfactory» (Cronbach’s Alpha= 0.803). Mean scores of the questionnaire were generally high [M:25.3;IC(24.7-25.9); W:24.3;IC(23.7-25.0)], indicating a good perceived masticatory efficiency. In contrast, mean scores of the masticatory performance test were rather low [M:60.8%;IC(57.3-64.2); W:61.2%;IC(57.7-64.7)]. No significant relationship between perceived and measured masticatory efficiency has been observed (r= -0.14; p= 0.22). A high prevalence (78.9%) of inadequate dietary intake of fruits and vegetables (<7 servings/day), resulting in high levels (53,9%) of inadequate folate intake for women (<320μg/d). After adjusting for age, sex, education and income, the masticatory efficiency score was not significantly associated with food intake Discussion/Conclusion: Despite a good internal consistency of the questionnaire, and the recognized validity of the test, it seems that people's perception of their masticatory efficiency does not reflect "real" efficiency as measured by the test. Furthermore, no relationship was observed between masticatory efficiency and food intake. New masticatory tests, more related to impact on swallowing and digestion, should be developed.

Background: Obesity continues to be one of the largest public health concerns in our nation. The role of eating patterns as a means for weight management has been studied extensively. However, the role of breakfast in weight management is still poorly understood. The purpose of this study was to understand the role of breakfast in weight management by observing the relationships of energy intake and macronutrient composition, specifically protein and fiber, with weight status during early morning and late morning eating occasions. Methods: Data from two multiple pass 24h dietary recalls from NHANES 2005-2010 were used. N= 4542 non-pregnant, non-lactating participants aged 20-65 y who did not perform shift work and who had a BMI between 18.5 and 60 kg/m2 were included. Individuals with missing data for any of the variables were excluded. Data were analyzed with SPSS software version 21. Each of the 2 days was divided into four time periods: time period 1 defined as the first intake of the day occurring between 12:00 a.m. and 4:59 a.m., time period 2 defined as the first intake occurring between 5:00 a.m. and 8:59 a.m., time period 3 defined as the first intake occurring between 9:00 a.m. and 11:30 a.m., and time period 4 defined as the first intake occurring after 11:30 a.m. Time period 2 was designated as “early morning intake” and time period 3 was designated as “late morning intake”. The other two time periods were designated as energy intake eaten the rest of the day. Energy (kcal), protein (g), and fiber (g) intakes were then calculated for the whole day and for each time period. For early morning and late morning intake, energy, protein and fiber were also divided into 5 categories. Those reporting no intake (0 kcals) made up the first category and quartiles were calculated for those reporting energy intakes of ≥ 0.1 kcal. Modified quartiles for the late morning period using the quartile cutoffs for the early morning time period were also calculated. Similarly, those reporting no intake (0 grams) made up the first category for protein and fiber and quartiles were calculated for those reporting protein or fiber intakes of ≥ 0.01 g. Estimated energy requirements (EER) were determined using the prediction equations developed by the Institute of Medicine (IOM 2005). To determine energy intake reporting plausibility, reported energy intake as a percent of EER was calculated. Standard classifications were used for weight status based on BMI. Descriptive statistics (median and 95% confidence interval) were computed for all variables. Multinomial logistic regression analysis was performed to determine associations between morning energy intake, protein, and fiber categories and risk for overweight (OW) and obesity (OB) for both early morning and late morning time periods. For the energy intake categories, Model 1 was controlled for race/ethnicity, age, gender, poverty-income ratio (PIR), smoking status, alcohol consumption, physical activity, self-reported chronic disease, daily eating frequency, and the two day morning eating pattern. Model 2 was controlled for all of the covariates in Model 1 plus energy intake before and after morning eating. Model 3 was controlled for all of the covariates in Model 2 plus energy intake reporting plausibility. For the protein and fiber categories, Model 1, 2, and 3 controlled for the same covariates as the energy intake categories and also controlled for reported energy intake during the early or late morning eating occasions. A p-value of <0.05 was considered statistically significant. Results: For the energy intake categories during the early morning, compared to no morning intake, Model 1 showed a lower risk for OB in Q2, but no other relationships were seen in any of the other quartiles. Similar results were seen in Model 2 where a lower risk for OB in Q2 was present. In Model 3, however, (controlled for energy intake reporting plausibility) the relationship between energy intake in Q2 and a lower risk for OB disappeared and a higher risk for OW and OB became apparent in Q4. For the late morning analysis, Models 1 and 2 were similar in that there was no association between morning energy intake category and weight status, but for Model 3 there was a higher risk for OW and OB in Q2-Q4. When we used the modified late morning quartile cutoffs in the analysis to eliminate potential bias due to the different quartile cutoffs for the early and late morning eating occasions, the higher risk for OW and OB was still present in Q2-Q4 and the ORs were attenuated compared to when the original late morning cutoffs were used. In terms of composition, compared to no morning intake, there were no significant associations seen between early or late morning protein consumption and weight status in any of the models. Additionally, for the early morning analysis of fiber, Models 1 and 2 did not show an association between morning fiber intake category and weight status, but for Model 3 there was a lower risk for OB in Q4. For the late morning analysis, Model 1 showed a higher risk for OW in Q2, but no other relationships were seen in any of the other quartiles. Similar results were seen in Model 2 where a higher risk for OB in Q2 was present. In Model 3, however, this relationship disappeared and no other associations were seen in any of the other quartiles. Conclusion: In comparison to having no morning intake (i.e., “skipping”) there was an elevated risk for OW and OB when consuming higher amounts of energy during the early morning and moderate to high amounts of energy during the late morning. The risk for OW and OB was higher in the late morning compared to the early morning eating occasions, in part, but not entirely, because of the higher amounts of energy consumed during the later morning in comparison to the early morning. Therefore, higher energy in both early morning and late morning increase the risk for OW and OB. Furthermore, later timing may increase the risk for OW and OB, independent of energy intake the rest of the day, since individuals who ate later also had higher energy intakes in the later morning compared to the early morning. In addition, compared to no morning intake of fiber, having a very high fiber intake in the early morning, but not the late morning, may decrease the risk for OB independent of energy intake and fiber intake the rest of the day. These associations may not be apparent unless energy intake reporting plausibility is taken into account.

In recent years there has been growing interest in the role of gut hormones in regulating appetite, energy balance and weight control. Prominent among these hormones is the hunger hormone ghrelin which is the only circulating hormone currently known to stimulate appetite. A variety of hormones are known to suppress appetite and notable among these is peptide YY (PYY). Both ghrelin and PYY exist in more than one form with acylated ghrelin and PYY3-36 representing the biologically active forms of these hormones i.e. the form of each hormone with the most potent effects on appetite. Many studies have investigated ghrelin responses to exercise in male participants and some studies have also examined PYY responses. Far fewer studies have examined ghrelin and PYY responses in female participants and this was the primary purpose of the studies reported here. This thesis comprises four main experimental chapters which collectively sought to clarify whether there is any evidence to support the hypothesis that appetite, gut hormone and food intake responses differ in female compared with male participants. A total of 123 participants took part in the studies reported in this thesis. The first of these studies was cross-sectional in nature and compared fasting appetite, plasma acylated ghrelin and dietary restraint questionnaire values (among other variables) in 34 males and 33 females. No significant differences were observed between sexes for any of these variables. In the second study, appetite, plasma acylated ghrelin and ad libitum food intake responses to cycling exercise were examined in 13 female participants taking the oral contraceptive pill in both the luteal and follicular phases of the menstrual cycle. Although fasting hunger and prospective food consumption values were higher in the follicular than the luteal phase there was no difference in appetite, plasma acylated ghrelin and food intake responses to exercise between menstrual cycle phases. In the third study, appetite, plasma acylated ghrelin, plasma PYY3-36 and food intake responses to energy deficits created via diet and exercise were compared in 13 young, healthy female participants who completed three separate trials (control, exercise deficit and food deficit) in a random order. The findings revealed that, as with male participants, females experience compensatory appetite, gut hormone and food intake responses to dietary induced energy deficits but not to exercise induced energy deficits (over the course of a nine hour observation period). The final study reported in this thesis compared appetite, plasma acylated ghrelin and ad libitum food intake responses to a one hour run in 10 male and 10 female participants. Suppressions of both hunger and plasma acylated ghrelin were noted during exercise but there was no significant difference in the responses of males and females during or after exercise. Collectively, the studies reported here suggest: 1) that fasting appetite and plasma acylated ghrelin concentrations do not differ between male and female participants; 2) that appetite, ghrelin and food intake responses to cycling exercise do not differ according to the phase of the menstrual cycle in females; 3) that dietary restriction is more likely to elicit compensatory feeding responses than elevated exercise levels in females and 4) that males and females do not differ in their acute appetite, ghrelin and food intake responses to an acute bout of running exercise. Hence the studies reported here do not support the hypothesis that exercise will be less effective for controlling appetite and food intake in females than in males.

Focusing on reducing the air consumption of an air flotation rail system, a flowrate-amplified flotation element was recently developed. This new flotation element ulitises the rotational flow to intake extra air via an intake hole, and thus, effectively improves the flotation height. Compared to a conventional flotation element, the flowrate-amplified flotation element can reduce air consumption by approximately 50% for the same load and flotation height. To gain an understanding of the flow phenomenon in the flowrate-amplified flotation element, experiments and CFD simulations are conducted in this study. Based on the results, we found that the flowrate-amplified flotation element could take a part of the kinetic energy of the rotating air to suck in extra air. The intake hole greatly affects the pressure field and velocity field of the flotation element. Additionally, the effects of the variant gap height and supplied flow rate were also discussed. The results indicate that the pressure distribution decreases as the gap height increases and increases as the supplied flow rate increases.

Understanding the physiological and behavioural reasons that result in voluntary water intake and the volume subsequently consumed in both the work place and during and following an exercise setting can provide further information on water balance and the necessity and requirements of water intake. The first study (Chapter 3) aimed to assess hydration status in the adult population at the start and end of a working day and the amount of water from beverages that was consumed. Urine osmolality and urine specific gravity (USG) suggested a large proportion of subjects arrived (osmolality: 54%; USG: 53%) and left (osmolality: 35%; USG: 33%) work in a hypohydrated state, with variation between subjects in the same and different places of work. Reported water intake varied between groups with males consuming more than females. To further examine hydration status it was proposed to assess the use of capillary blood sampling as an alternative to more restrictive venous blood sampling (Chapter 4), however, despite tracking changes in blood parameters in a similar capacity, the inconsistencies of results suggested capillary blood sampling could not be used reliably. The remaining chapters in the thesis examined voluntary water intake. In Chapter 5 this was during and following exercise in the cold. Less water was consumed compared to exercise in a warm environment and there was an indication of a blunted thirst response in the cold. Following high intensity intermittent exercise, more water was voluntarily consumed during a one hour recovery period compared to when continuous exercise of the same average power output was performed (Chapter 6). Following exercise there was increased serum osmolality, serum sodium concentration, plasma vasopressin concentration and blood lactate concentration compared to baseline values. The relative contribution that decreasing blood lactate concentrations and water intake during the recovery period had on serum osmolality could not be determined, so the study in Chapter 7 was carried out. The time period during which voluntary water intake was allowed was manipulated during a recovery period following a period of high intensity intermittent exercise. Allowing water intake for the full hour, the final 30 minutes or not at all, resulted in similar decreases in serum osmolality throughout the duration of the recovery period. A combination of finishing the period of exercise allowing plasma volume restoration, reduction in blood lactate concentration, reduction in serum sodium concentration, a restoration of blood lactate concentration and water intake appeared to contribute to decreased serum osmolality. Sensations of thirst were the main stimulants of voluntary water intake (Chapters 3, 5, 6 and 7), however, following exercise, sensations of thirst resulted in water consumption despite the majority of subjects not losing enough water (>2% body mass loss) to require additional rehydration. In this thesis, it can be concluded that voluntary water intake differs between individuals, between work environments, during and following exercise in different environments and following different exercise intensities. Water intake is generally initiated by sensations of thirst arising from physiological and behavioural mechanisms even in the absence of significant hypohydration and will reduce once satiated.

At present, the process of parental modelling of eating behaviours and attitudes has received limited research interest. While often mentioned as a possible factor in relation to child feeding and the development of eating behaviours, only a few studies have explicitly researched parental modelling. The main aims of this thesis were to develop a new measure to assess modelling multidimensionally and to explore the relationships between parental modelling of eating behaviours with a variety of parent and child factors. Initially, a parental self-report measure (the Parental Modelling of Eating Behaviours Scale; PARM) was developed, validated and piloted as part of a series of studies exploring the associations between modelling and a range of self-reported parental and child factors. To provide further validation for the PARM, an observational coding scheme was developed, based on the newly developed modelling measure, and this was utilised in two further studies which looked at self-reported and observed parent and child factors. The key findings from this thesis suggest a number of beneficial relationships. For example, maternal modelling was positively correlated with healthy food intake in both mothers and their children. In addition, both maternal and paternal modelling were associated with children s increased enjoyment of food and lower levels of food fussiness. Observations of maternal modelling were also found to be positively related to other observed adaptive, non-directive feeding practices, such as encouragement to eat. However, less positive relationships were also identified, with modelling being related to parents mental health symptoms and to unhealthy food intake in both mothers and their children. In conclusion, this thesis has identified three distinct facets of modelling and highlighted factors which might be linked to parental role modelling around eating behaviours. While much of the research within this thesis is exploratory, and the findings require replication, they would suggest that parental modelling has the potential to positively influence children s eating behaviours. However, parents should also be made aware of the potential detrimental effect that modelling less adaptive eating behaviours may have on their children s food intake, particularly those eating behaviours that parents may be unaware of modelling.