I conducted electrophysiological work in C57BL/6J (B6) and PWD/PhJ (PWD) mice, with the goal of providing insight into the genetic and physiological controls of calcium intake. Prior behavioral preference tests indicated that PWD mice have higher preferences for calcium compounds compared to B6 mice, though several mechanisms could underlie this observation. I therefore measured taste-evoked chorda tympani (CT) responses in B6 and PWD mice, in order to investigate the specific role of taste sensation. A second experiment was conducted to investigate the role of the calciumsensing receptor (CaSR) is in gustatory transduction of calcium ions, using the CaSR agonist glutathione. In experiment 1, responses were significantly larger in PWD than B6 mice for CaCl2, MgCl2, citric acid and quinine, but did not differ between the strains for sucrose, KCl and NaCl. These strain differences in CT responses were especially large for tonic, rather than phasic, responding. These data suggest that differences in peripheral events, such as taste transduction, contribute to differences between B6 and PWD mice in preferences for taste solutions such as CaCl2. In experiment 2, glutathione at 100 μM had negligible effects on taste-evoked CT responses, which does not support a role for CaSR in mediating taste transduction of calcium ions. / Department of Physiology and Health Science

Vegetables and fruit appear to confer protection against various diseases, but most adults in South Africa eat substantially less than the recommended amounts. Many barriers and factors that influence vegetable consumption have been identified in the literature. One major barrier is the perishability of vegetables. Frozen vegetables can be a useful way in encouraging greater intakes. Some consumers are, however, of the opinion that processing destroy nutrients to a large extent. There is, therefore, a lack of understanding of the freezing process. Research on the attitudes of consumers towards frozen vegetables in South Africa is limited. Objective: The purpose of this study was to determine the attitudes of consumers regarding the link between frozen and fresh vegetables and health and the attributes of frozen vegetables. Subjects/Setting: One thousand nine hundred and ninety seven South African respondents, representative of the four major race groups of South Africa (whites, blacks, coloureds and Indians) were randomly chosen from metropolitan areas from the nine provinces in South Africa. Questionnaires, existing of 17 food-related sections, including subsections on vegetables and health, were designed by researchers in co-operation with business partners. MARKINOR, a market research company, was contracted to collect the data. Respondents were questioned regarding their attitudes towards the link between frozen and fresh vegetables and health. Statistical analysis performed: The quantitative data produced by the survey was analysed by using the StatisticaⓇ-programme in order to generate the relevant tabulations, descriptive statistics and statistical tests. Results: Overall, the attitudes of consumers towards frozen vegetables were found to be negative. Practical and statistically significant attitude differences towards frozen vegetables were found between most variables. Results from this study revealed that different levels of education, age and gender do not have a big influence on consumer's attitudes towards frozen vegetables. However, practical and statistically significant differences were found between the various LSM (Living Standards Measure) groups, especially with regard to the convenience of frozen vegetables. Results also indicated that Indians, the age group 61+ and males were the most negative towards frozen vegetables. Almost 75% of all consumers indicated that they never eat frozen vegetables. Only 1% of consumers in the LSM group 2 own a fridge/freezer. An alarmingly 26% of all consumers indicated that they are not convinced that vegetables are healthy. Application/Conclusions: Nutrition professionals should use these findings to target messages in health-promotion programmes to increase the overall consumption of vegetables. The use of frozen vegetables by consumers with frozen storage facilities should be promoted aggressively. Consumers also need practical advice on how to overcome the barriers to dietary change. Nutrition counseling efforts should also be aimed specifically at increasing frozen vegetable consumption among targeted subgroups, particularly Indians, males and the age group 61+. It is strongly recommended that suitable measuring instruments be developed for assessing the knowledge and attitude of South Africans towards vegetable and fruit consumption and the ability of individuals to improve their health. The results of this study may prove to be very useful in this regard. / Thesis (M.Sc. (Dietetics))--North-West University, Potchefstroom Campus, 2004.

Customer perception and the way this phenomenon impacts customers' choices when purchasing products is an extremely significant marketing aspect in any industry. In a competitive market and economy, understanding and being able to predict consumer perceptions and responses is a crucial competitive factor that all suppliers should have an in–depth knowledge and understanding of. This applies especially to the South African beer market with more than forty competing beer brands. This study examines the aspect of customer perception in terms of the three central variable perceptions of price, taste and brand image. Furthermore, the study takes into account the interaction between these variables and attempts to ascertain whether one is more significant than the other. To this end an empirical research study was undertaken by means of a questionnaire that examined the responses from 225 participants. These responses were analysed in terms of a number of significant variables in relation to perceptions of price, taste and brand image. The results were also compared to the literature and theory on the subject. Among the findings from this research was that while all variables were important, price was considered by the participants to be a constant factor in the decision–making process. However, it was also found that price as a perception could not be viewed in isolation as a separate and autonomous variable. It was found that aspects such as brand image could have a significant impact on other perceptual factors such as taste. The study concludes with the recommendation that the perceptions of price, taste and brand image should be considered in terms of their affect on each other and should be further researched in terms of a more holistic understanding of their interconnections. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2012.

Customer perception and the way this phenomenon impacts customers' choices when purchasing products is an extremely significant marketing aspect in any industry. In a competitive market and economy, understanding and being able to predict consumer perceptions and responses is a crucial competitive factor that all suppliers should have an in–depth knowledge and understanding of. This applies especially to the South African beer market with more than forty competing beer brands. This study examines the aspect of customer perception in terms of the three central variable perceptions of price, taste and brand image. Furthermore, the study takes into account the interaction between these variables and attempts to ascertain whether one is more significant than the other. To this end an empirical research study was undertaken by means of a questionnaire that examined the responses from 225 participants. These responses were analysed in terms of a number of significant variables in relation to perceptions of price, taste and brand image. The results were also compared to the literature and theory on the subject. Among the findings from this research was that while all variables were important, price was considered by the participants to be a constant factor in the decision–making process. However, it was also found that price as a perception could not be viewed in isolation as a separate and autonomous variable. It was found that aspects such as brand image could have a significant impact on other perceptual factors such as taste. The study concludes with the recommendation that the perceptions of price, taste and brand image should be considered in terms of their affect on each other and should be further researched in terms of a more holistic understanding of their interconnections. / Thesis (M.B.A.)--North-West University, Potchefstroom Campus, 2012.

Syftet med denna undersökning är att undersöka blivande idrottslärares erfarenheter av och smak för natur och friluftsliv och hur det kommer till uttryck i deras föreställningar om natur och friluftsliv i utbildningen och skolämnet idrott och hälsa. I studien, som har en kvalitativ ansats, har använts ostrukturerade intervjuer i fokusgrupper. Resultatet är analyserat med hjälp av Bourdieus teorier och begrepp om fält, kapital, habitus och smak. Resultatet visar att respondenterna i denna studie har erfarenhet av friluftsliv av det enkla slaget. När de börjar sin lärarutbildning i friluftsliv uppstår en krock i mötet mellan respondenternas habitus med enkelt friluftsliv i närmiljön och lärarutbildningens ”spelregler” där vana och erfarenheter av mer exklusivt friluftsliv erkänns värde. Smak eller avsmak för friluftsliv förstärks under utbildningen. Respondenterna upplever också en problematik med tolkning av begreppen natur och friluftsliv som är mångfasetterade. Natur beskrivs som å ena sidan orörd vildmark och å andra sidan som en park i staden. En aktivitet betraktas som friluftsliv i ett sammanhang och samma aktivitet betraktas som idrott i ett annat.  Resultatet visar också på en samsyn hos respondenterna vad gäller hur undervisning i friluftsliv inom ämnet idrott och hälsa ska genomföras i framtidens skola. Intresse eller smak för friluftsliv är enligt respondenterna en förutsättning för att kunna undervisa på ett professionellt sätt. Det räcker inte med att vara kompetent didaktiskt och färdighetsmässigt och en viktig aspekt för respondenterna är också att följa styrdokumentens intentioner vad gäller friluftsliv. / The purpose of this study is to investigate the prospective PE teachers' experiences of and taste for nature and outdoor life, how it is reflected in their beliefs about nature and outdoor activities in education and school physical education. The method of the study, which has a qualitative approach, has been unstructured interviews and focus groups. The results are analyzed with the help of Bourdieu's theories and concepts of field, capital, habitus and taste. The result shows that the respondents in this study have had experiences of outdoor activities that are of a simple nature. When they start their teacher training in outdoor activities, there is a collision between the respondents' habitus with simple outdoor life in their local environment and the teacher training "game rules" where the experience of more upscale and advanced outdoor activities are recognized and valued. Taste or distaste for outdoor activities is amplified during training. Respondents also experience problems with the interpretation of the concepts of nature and outdoor activities that are multifaceted. Nature is described on the one hand as untouched wilderness and on the other hand as a park in the city. An activity is considered an outdoor activity in one context and the same activity is regarded as a sport in another context. The results also show a consensus among respondents when regarding the teaching of outdoor activities in physical education and how it should be implemented in the future of the school. Interest in or a taste for outdoor activities, according to respondents, is essential to teach in a professional manner. It is not enough to only have a didactic skill but an important aspect for the respondents are also the ability to follow the policy documents’ intentions with regard to outdoor recreation.

I tested the efficacy of aversive conditioning (AC) and conditioned taste aversion (CTA) on American black bears (Ursus americanus) in Whistler, British Columbia. Black bears subjected to 3-5 day AC programs responded by increasing their wariness toward humans, while control bears habituated. Bears were located closer to human developments during daylight hours after AC treatments. However, there was no difference in the proportion of utilization distribution that overlapped with developed areas in control or AC-treated bears. CTA may be effective for managing specific attractants that are difficult to secure from bears. Bears appeared to distinguish between baits treated with thiabendazole and baits that were not treated, but by using a protocol that caused severe illness and left the source of illness in doubt, I induced taste aversions to apples in 4 bears. Using both AC and CTA may help wildlife managers mitigate human-wildlife conflicts non-lethally more effectively. / Ecology

Ecological modelling problems have characteristics both featured in other modelling fields and specific ones, hence, methods developed and tested in other research areas may not be suitable for modelling ecological problems or may perform poorly when used on ecological data. This thesis identifies issues associated with the techniques typically used for solving ecological problems and develops new generic methods for decision support, especially suitable for ecological data modelling, which are characterised by: (1) adaptive learning, (2) knowledge discovery and (3) accurate prediction. These new methods have been successfully applied to challenging real world ecological problems. Despite the fact that the number of possible applications of computational intelligence methods in ecology is vast, this thesis primarily concentrates on two problems: (1) species establishment prediction and (2) environmental monitoring. Our review of recent papers suggests that multi-layer perceptron networks trained using the backpropagation algorithm are most widely used of all artificial neural networks for forecasting pest insect invasions. While the multi-layer perceptron networks are appropriate for modelling complex nonlinear relationships, they have rather limited exploratory capabilities and are difficult to adapt to dynamically changing data. In this thesis an approach that addresses these limitations is proposed. We found that environmental monitoring applications could benefit from having an intelligent taste recognition system possibly embedded in an autonomous robot. Hence, this thesis reviews the current knowledge on taste recognition and proposes a biologically inspired artificial model of taste recognition based on biologically plausible spiking neurons. The model is dynamic and is capable of learning new tastants as they become available. Furthermore, the model builds a knowledge base that can be extracted during or after the learning process in form of IF-THEN fuzzy rules. It also comprises a layer that simulates the influence of taste receptor cells on the activity of their adjacent cells. These features increase the biological relevance of the model compared to other current taste recognition models. The proposed model was implemented in software on a single personal computer and in hardware on an Altera FPGA chip. Both implementations were applied to two real-world taste datasets.In addition, for the first time the applicability of transductive reasoning for forecasting the establishment potential of pest insects into new locations was investigated. For this purpose four types of predictive models, built using inductive and transductive reasoning, were used for predicting the distributions of three pest insects. The models were evaluated in terms of their predictive accuracy and their ability to discover patterns in the modelling data. The results obtained indicate that evolving connectionist systems can be successfully used for building predictive distribution models and environmental monitoring systems. The features available in the proposed dynamic systems, such as on-line learning and knowledge discovery, are needed to improve our knowledge of the species distributions. This work laid down the foundation for a number of interesting future projects in the field of ecological modelling, robotics, pervasive computing and pattern recognition that can be undertaken separately or in sequence.

Research Doctorate - Doctor of Philosophy (PhD) / This thesis investigates mechanisms of brain maturation by utilising the special advantages offered by the protracted maturation of neural circuits in chicken forebrain. Biochemical, behavioural and electrophysiological techniques are used in behaving animals to investigate the functional consequences of maturation changes at the molecular, behavioural and physiological levels. Two issues are addressed: (1) do immature (2 week) and mature (8 week) chickens employ different molecular mechanisms to produce changes in neuronal function after learning a behavioural task; and (2) can quantitative non-invasive measures of neuronal function be used to monitor maturation changes in chicken forebrain? Biochemical investigation of subcellular fractions using antibodies and western blots of chicken forebrain and intermediate medial mesopallium (IMM) revealed regional differences in expression levels of a number of components of the glutamatergic neurotransmitter system. The discriminative taste aversion learning (DTAL) task was used to assess whether an animal learns the same task at different ages using different intracellular signalling pathways. The patterns of biochemical change seen in the IMM after DTAL training was very different at 2 weeks and 8 weeks. Two major differences were observed. Firstly, the same type of training induced changes occurred at both ages in GluR1 and CaMKII but they occurred faster at 8 weeks. Secondly the difference in ERK and CREB responses is consistent with a change in the relative contribution made by the ERK signalling pathway and CREB requirement to learning at these two ages. These results imply that the molecular changes induced by learning a behavioural task are faster in mature than immature brain and may involve a different balance of intracellular signalling pathways. In order to be able to investigate biological mechanisms controlling maturation and to use the chicken as an animal model in which pharmacological and/or environmental agents can be screened for potentially harmful effects on brain maturation two non-invasive measures of neuronal function were investigated. One was behavioural (prepulse inhibition: PPI) and the other was electrophysiological (auditory evoked related potentials: AERP). PPI in the chicken was examined electromyographically and via whole body movement with a stabilimeter apparatus. In two strains of chicken (a meat breed and a laying breed) PPI was identified but shown to be small and variable compared to that in the rat. The results indicate that the phenomenon of PPI in the chicken is too small and variable to be used as a quantitative measure of neural circuit maturation. Quantitative analysis of the chicken AERP revealed a significant decrease in amplitude of the positive AERP component and a decrease in latency of the negative AERP component with maturation. These maturation changes were comparable to developmental changes seen in human and other mammal AERPs. Such changes may reflect changes in the intracortical synaptic organisation of the auditory cortex. This technique allowed for repeated measures to be undertaken on the same animal over a number of weeks and enabled developmental changes to be monitored. This technique was extended to investigate perturbed maturation via the induction of chemically induced hypothyroidism. Results from this study showed that the induction of late onset hypothyroidism produces measurable effects on the chicken AERP consistent with perturbation in maturation of neuronal circuits and synapses. This suggests that AERPs may be useful non-invasive functional measures of brain maturation that can be used to study the effects of endogenous or exogenous factors on brain maturation in the chicken. Since human brain also exhibits a protracted maturation period the availability of a well characterised animal model for protracted brain maturation provides an opportunity to identify molecules, genes and environmental factors that are important in the regulation of maturation. Such a model may provide the basis for developing rational therapies or prevention strategies for some neurodevelopmental disorders. The protracted maturation of neuronal circuits observed in chicken forebrain offers such a model.

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniversitet, 2005. / Härtill 4 uppsatser.

Thesis (Ph. D.)--State University of New York at Binghamton, Psychology Department, 2005. / Includes bibliographical references.