No description available.

The placenta is thought to play a vital role in the transfer of essential fatty (EFA) and their long-chain polyunsaturated derivatives (LCPUFA) from mother to the fetus. There is a preferential accumulation of these fatty acids from maternal to fetal tissues. However, little was known about the manner in which these nutrients preferentially traversed the placenta. This study investigated part of this placental transport mechanism. The results from these investigations demonstrated that the preferential transport of LCPUFA to the fetal circulation may at least be partially mediated by a preferential uptake system in the placenta involving a 40 kDa, placental membrane fatty acid binding protein (p-FABP_pm). This protein was found exclusively in the maternal facing microvillous membranes. It was characterised as different from previously identified ubiquitous FABP_pm by virtue of having a different pl value, different amino acid composition, no aspartate aminotransferase activity and a higher binding affinity for LCPUFA over non-essential fatty acids. The human choriocarcinoma cell line (BeWo) expressed a protein immunoreactive to anti-p-FABP_pmanti-serum. This anti-serum inhibited the binding of LCPUFA to placental membranes and the uptake of LCPUFA by BeWo cells, to a greater degree than it inhibited the uptake and binding of non essential fatty acids. In addition to p-FABP_pmthe existence of multiple types of both cytosolic (L-FABP and H-FABP) and membrane (FAT and FATP) fatty acid-binding proteins was demonstrated in placental cells. These proteins could play important roles in both the uptake of fatty acids by the placenta and in controlling the fate of fatty acids inside placental cells.

No description available.

Access to abstract restricted until 05/2016. / Access to thesis restricted until 05/2016. / Department of Physics and Astronomy

Internprissättning är vanligt inom dagens koncerner och växer mer allt eftersom världshandeln har globaliserats. Användandet av internprissättning för att öka vinsten är en diskussion som tog fart redan på 1950-talet. En diskussion som baserats på att bolag medvetet förbättrar sin skatt genom de olika metoderna som finns. Ett utnyttjande av regleringars brister och otydliga tolkningar. Ämnet är speciellt då det kräver kunskap inom både företagsekonomi och juridik. Att ämnet är brett gör det än mer komplext och en bredare kunskap krävs för att fullt förstå dess problematik. / Transfer pricing is common in today's corporations and grows more as world trade has become globalized. The use of transfer pricing to increase profits is a discussion that took off in the 1950's. A discussion based on the company consciously improve their taxes through the various methods available. A utilization of regulation flaws and unclear interpretations. The topic is unique because it requires expertise in both business administration and law. That the subject is wide makes it even more complex and broader knowledge required to fully understand its problems.

There is no abstract available for this dissertation.

The present research focused on the transfer of information from a learning situation to a problem solving task. In particular, the effect of relational processing upon the transfer of information to the solution of insight problems was considered.The design of the study was a five by two factorial design. Within this design the independent variables were five levels of relational processing, ranging from full relational processing (essay) to individual item processing (deleted letter list) and two levels of instruction, informed and uninformed. The dependent measure was the number of insight problems correctly solved. The problems consisted of ten statements which did not make sense unless one part of the sentence was modified. The subject's task was to supply the necessary information needed to make sense of the sentence.The results showed no effect for type of instruction and there was no interaction between the type of instruction and level of relational processing. There was a significant effect due to level of relational processing. More specifically, the essay condition lead to the greatest amount and individually processed items lead to the lowest amount of information transfer. Further, it was suggested that the relationship between relational processing and the transfer of information was linear. These findings were interpreted as indicating that relational processing was a significant factor in explaining the transfer of information. / Department of Educational Psychology

The work presented within this dissertation focusses on the development of affinite element method (FEM) model for the microwave absorption and heat transfer within a microwave combination washer dryer (MCWD). FEM will be used to aid in the implementation of more advanced fluid dynamics such as laminar or turbulent flow, that may be present within the system. The intended use of the model is to aid a South African based company in the development of a control system for the MCWD. The model development presented focusses on the washing cycle of the MCWD and will therefore not take into account the drying cycle of the system. The target of the microwave heating within the model will be distilled water as the dielectric constant of water is a know quantity. Various literature sources on microwave absorption and heat transfer models can be found, but none specific to the topic of the combination washer dryer. By reviewing literature from various sources, the finite element method was selected as the modelling technique and the COMSOL® software package was selected as the tool for developing the model. A model for the MCWD will be developed within the COMSOL® environment which in turn implements FEM as a technique to solve the model. The model development is broken into nine stages. Stage one start by modelling the heat transfer within the washing drum. Each consecutive stage expands the model by adding features or model domains. Model verification takes place in parallel to the development by verifying each stage before moving to the next stage. The stage eight and nine models, which represent a full three dimensional model of the system, are selected to be validated as the final models. Stage eight models the system without an enclosure and makes use of convective cooling boundary conditions on the boundary of the air enclosed within the system enclosure. Stage stage nine models the system with the aluminium enclosure of the system and also implements convective cooling boundary conditions on the outer boundary of the aluminium. The boundary between the enclosed air and aluminium enclosure is implemented as a normal convective heat transfer boundary between a gas and solid. Data capturing is done using the dSpace® platform. Sensors to log the microwave power and system temperature are selected and optimal placement of the sensors is evaluated. The capturing platform is interfaced to the sensors by an in-house developed signal conditioning board. Model validation is completed by comparing the response of the model to the practical system. Numerous simulations are completed to select the optimal configuration of the model that provides the optimal response. The stage eight model was found to be more accurate then the stage nine model with respect to the difference between the simulated and expected response over the whole domain of the transient temperature response. A further method implemented to easily compare the results of various simulations is by comparing the average absolute temperature of the response over the whole domain of the transient response. The average absolute temperature is calculated by taking absolute difference between the expected results and the model response at each time step within the response domain and then to average the absolute difference. This enables the comparison of two responses using two values. Needles to say this method should not be used alone and should be used in conjunction with a comparison over the full response domain. Use of the average absolute temperature difference is aimed at filtering the results from a selection of results which warrants a more in depth investigation. Using a comparison of the average absolute temperature difference of the target in the 500 W model, it was found that their respective values are 2:92 °C and 11:36 °C. The stage eight model computation time was far less than the stage nine model and is therefore recommended for further development. The final conclusion was made that the stage eight model represents the system fairly accurately at this stage and warrants further development by expanding the model to account for the drying cycle of the MCWD. The term fairy accurate is used to describe the results as further improvement of the model is definitely possible with regards to the accuracy of the transient response of the system. Further improvement of the model response may be possible by implementing a smaller mesh size or launching an in depth study on the effect of the various material thermal properties on the response of the system during various stages. For instance below a certain temperature the response closely represents the expected response and above that temperature the response various greatly from the expected response. Future work on the model include, to change the target from distilled water to an actual representation of the textiles intended to be washed within the MCWD. This will require a study into how the various parameters such as the density and dielectric constant, of the heterogeneous mixtures of textiles and water, can be combined for use into the model. As a next step in the expansion of the model, the model can be configured to account for the drying cycle of the system which will require the model to account for the phase changes that the water will undergo. / Thesis (MIng (Computer and Electronic Engineering))--North-West University, Potchefstroom Campus, 2013.

The work presented within this dissertation focusses on the development of affinite element method (FEM) model for the microwave absorption and heat transfer within a microwave combination washer dryer (MCWD). FEM will be used to aid in the implementation of more advanced fluid dynamics such as laminar or turbulent flow, that may be present within the system. The intended use of the model is to aid a South African based company in the development of a control system for the MCWD. The model development presented focusses on the washing cycle of the MCWD and will therefore not take into account the drying cycle of the system. The target of the microwave heating within the model will be distilled water as the dielectric constant of water is a know quantity. Various literature sources on microwave absorption and heat transfer models can be found, but none specific to the topic of the combination washer dryer. By reviewing literature from various sources, the finite element method was selected as the modelling technique and the COMSOL® software package was selected as the tool for developing the model. A model for the MCWD will be developed within the COMSOL® environment which in turn implements FEM as a technique to solve the model. The model development is broken into nine stages. Stage one start by modelling the heat transfer within the washing drum. Each consecutive stage expands the model by adding features or model domains. Model verification takes place in parallel to the development by verifying each stage before moving to the next stage. The stage eight and nine models, which represent a full three dimensional model of the system, are selected to be validated as the final models. Stage eight models the system without an enclosure and makes use of convective cooling boundary conditions on the boundary of the air enclosed within the system enclosure. Stage stage nine models the system with the aluminium enclosure of the system and also implements convective cooling boundary conditions on the outer boundary of the aluminium. The boundary between the enclosed air and aluminium enclosure is implemented as a normal convective heat transfer boundary between a gas and solid. Data capturing is done using the dSpace® platform. Sensors to log the microwave power and system temperature are selected and optimal placement of the sensors is evaluated. The capturing platform is interfaced to the sensors by an in-house developed signal conditioning board. Model validation is completed by comparing the response of the model to the practical system. Numerous simulations are completed to select the optimal configuration of the model that provides the optimal response. The stage eight model was found to be more accurate then the stage nine model with respect to the difference between the simulated and expected response over the whole domain of the transient temperature response. A further method implemented to easily compare the results of various simulations is by comparing the average absolute temperature of the response over the whole domain of the transient response. The average absolute temperature is calculated by taking absolute difference between the expected results and the model response at each time step within the response domain and then to average the absolute difference. This enables the comparison of two responses using two values. Needles to say this method should not be used alone and should be used in conjunction with a comparison over the full response domain. Use of the average absolute temperature difference is aimed at filtering the results from a selection of results which warrants a more in depth investigation. Using a comparison of the average absolute temperature difference of the target in the 500 W model, it was found that their respective values are 2:92 °C and 11:36 °C. The stage eight model computation time was far less than the stage nine model and is therefore recommended for further development. The final conclusion was made that the stage eight model represents the system fairly accurately at this stage and warrants further development by expanding the model to account for the drying cycle of the MCWD. The term fairy accurate is used to describe the results as further improvement of the model is definitely possible with regards to the accuracy of the transient response of the system. Further improvement of the model response may be possible by implementing a smaller mesh size or launching an in depth study on the effect of the various material thermal properties on the response of the system during various stages. For instance below a certain temperature the response closely represents the expected response and above that temperature the response various greatly from the expected response. Future work on the model include, to change the target from distilled water to an actual representation of the textiles intended to be washed within the MCWD. This will require a study into how the various parameters such as the density and dielectric constant, of the heterogeneous mixtures of textiles and water, can be combined for use into the model. As a next step in the expansion of the model, the model can be configured to account for the drying cycle of the system which will require the model to account for the phase changes that the water will undergo. / Thesis (MIng (Computer and Electronic Engineering))--North-West University, Potchefstroom Campus, 2013.

This study investigated the most efficacious means of providing feedback to students on multiple-choice test items. Subjects were 135 undergraduate students enrolled at a mid-western university. Immediate feedback, defined as knowledge of correct results presented after the completion of the entire test, and delayed feedback, defined as knowledge of correct results presented 24 hours after the completion of the test, were examined. The presence or absence of an immediate retention test was also examined. The performance on the initial test, the students' verbal ability, and the amount of time spent with feedback were used as covariates. Also investigated was the relationship of the level of the test item (recall or complex) to the students' ability to profit from immediate or delayed feedback. The interference perseveration hypothesis was examined as a possible explanation of the delayed retention effect (DRE).Two analyses of the data were performed to test the DRE. The first was a univariate analysis of covariance of the four treatment conditions, utilizing the students' performance on the initial test, verbal ability and time spent with feedback as covariates. The results of this analysis were not significant. The second was a univariate analysis of covariance of the four treatment groups and the control group with the initial test score and the students' verbal ability covaried.The analysis yielded a significant treatment effect when the control group was compared to the four treatment conditions.The reliability correlation coefficients which were computed for the recall and complex test items were not adequate to be used in the analysis. Therefore the interaction between the level of the test items and the feedback condition was not tested.All of the students were asked to complete a pre- and postquestionnaire to assess their feedback preference and to determine if this preference changed over time. Results indicated the majority of students preferred to receive immediate feedback and little change was observed in their feedback preference.An item analysis was conducted in order to investigate the interference-perseveration hypothesis. The data did not support this theory.Conclusions were drawn and implications for further research were discussed.