The acute effects of differential dietary fatty acids on PDHa activity in human skeletal muscle at the onset of exercise

Pyruvate dehydrogenase (PDH) is an important regulator of carbohydrate oxidation during exercise and its activity can be down-regulated by an increase in dietary fat. The purpose of this study was to determine the acute metabolic effects of differential dietary fatty acids on the activation of PDH in its active form (PDHa) at rest and at the onset of moderate-intensity exercise. University-aged male subjects (n=7) underwent 2 fat loading trials spaced at least 2 weeks apart. Subjects consumed saturated (SFA) or polyunsaturated (PUFA) fat over the course of 5 hours. Following this, participants cycled at 65% VO2 max for 15 min. Muscle biopsies were taken prior to and following fat loading and at 1 min exercise. Plasma free fatty acids increased from 0.15 ± 0.07 to 0.54 ± 0.19 mM over 5 hours with SFA and from 0.1 1 ± 0.04 to 0.35 ±0.13 mM with PUFA. PDHa activity was unchanged following fat loading, but increased at the onset of exercise in the SFA trial, from 1 .4 ± 0.4 to 2.2 ± 0.4 /xmol/min/kg wet wt. This effect was negated in the PUFA trial (1 .2 ± 0.3 to 1 .3 ± 0.3 pimol/min/kg wet wt.). PDH kinase (PDK) was unchanged in both trials, suggesting that the attenuation of PDHa activity with PUFA was a result of changes in the concentrations of intramitochondrial effectors, more specifically intramitochondrial NADH or Ca^*. Our findings suggest that attenuated PDHa activity participates in the preferential oxidation of PUFA during moderateintensity exercise.

Asymmetries of Influence: Differential Effects of Body Postures on Perceptions of Emotional Facial Expressions

The accuracy and speed with which emotional facial expressions are identified is influenced by body postures. Two influential models predict that these congruency effects will be largest when the emotion displayed in the face is similar to that displayed in the body: the emotional seed model and the dimensional model. These models differ in whether similarity is based on physical characteristics or underlying dimensions of valence and arousal. Using a 3- alternative forced-choice task in which stimuli were presented briefly (Exp 1a) or for an unlimited time (Exp 1b) we provide evidence that congruency effects are more complex than either model predicts; the effects are asymmetrical and cannot be accounted for by similarity alone. Fearful postures are especially influential when paired with facial expressions, but not when presented in a flanker task (Exp 2). We suggest refinements to each model that may account for our results and suggest that additional studies be conducted prior to drawing strong theoretical conclusions.

Region Connection Calculus: Composition Tables and Constraint Satisfaction Problems

Qualitative spatial reasoning (QSR) is an important field of AI that deals with qualitative aspects of spatial entities. Regions and their relationships are described in qualitative terms instead of numerical values. This approach models human based reasoning about such entities closer than other approaches. Any relationships between regions that we encounter in our daily life situations are normally formulated in natural language. For example, one can outline one's room plan to an expert by indicating which rooms should be connected to each other. Mereotopology as an area of QSR combines mereology, topology and algebraic methods. As mereotopology plays an important role in region based theories of space, our focus is on one of the most widely referenced formalisms for QSR, the region connection calculus (RCC). RCC is a first order theory based on a primitive connectedness relation, which is a binary symmetric relation satisfying some additional properties. By using this relation we can define a set of basic binary relations which have the property of being jointly exhaustive and pairwise disjoint (JEPD), which means that between any two spatial entities exactly one of the basic relations hold. Basic reasoning can now be done by using the composition operation on relations whose results are stored in a composition table. Relation algebras (RAs) have become a main entity for spatial reasoning in the area of QSR. These algebras are based on equational reasoning which can be used to derive further relations between regions in a certain situation. Any of those algebras describe the relation between regions up to a certain degree of detail. In this thesis we will use the method of splitting atoms in a RA in order to reproduce known algebras such as RCC15 and RCC25 systematically and to generate new algebras, and hence a more detailed description of regions, beyond RCC25.