2 resultados para RC slabs
em Brock University, Canada
Resumo:
Hom's (2008) model of coaching effectiveness proposes a series of direct relationships between the beliefs and values of coaches, their behaviours, and the perceptions of their athletes. One specific area of coaching behaviour that is in need of more research is their use of psychological skills training (PSn. The purpose of this study was to examine the relationship between the beliefs and behaviours of curling coaches with respect to PST, and the perceptions of their athletes. In collaboration with the Canadian Curling Association, data was collected from a national sample of 115 curling teams with varying levels of competition and experience. One hundred and fifteen coaches completed PST attitude (SPA-RC-revised) and behaviour (MSQ-revised) measures, while 403 athletes completed two perception measures (CCS and S-CI). Interclass correlation coefficients (ICC) were calculated to ensure intra-team consistency. All ICCs were positive, ranging from r =.39 to .56, and significant at the p < .01 level. A series of multiple regressions were performed. Three of the four regression models were significant, with coaches' PST behaviours accounting for 16% of the variance in athletes' evaluation of their coaches' competencies (GeC). The models for athletes' PhysicalSport Confidence (P-SC) and Cognitive-Sport Confidence (C-SC) accounted for 15% and 36% of the variation, with GCC and coaches' PST behaviours both being significant predictors of the models. After statistically controlling the influence of GCC, coaches' PST behaviours accounted for 3% and 26% of the variation in athletes P-SC and C-SC. These results provide partial support for Hom's (2008) model of coaching effectiveness, and offer new insight into the benefits of coaches' use of sport psychology-related training behaviours.
Towards reverse engineering of Photosystem II: Synergistic Computational and Experimental Approaches
Resumo:
ABSTRACT Photosystem II (PSII) of oxygenic photosynthesis has the unique ability to photochemically oxidize water, extracting electrons from water to result in the evolution of oxygen gas while depositing these electrons to the rest of the photosynthetic machinery which in turn reduces CO2 to carbohydrate molecules acting as fuel for the cell. Unfortunately, native PSII is unstable and not suitable to be used in industrial applications. Consequently, there is a need to reverse-engineer the water oxidation photochemical reactions of PSII using solution-stable proteins. But what does it take to reverse-engineer PSII’s reactions? PSII has the pigment with the highest oxidation potential in nature known as P680. The high oxidation of P680 is in fact the driving force for water oxidation. P680 is made up of a chlorophyll a dimer embedded inside the relatively hydrophobic transmembrane environment of PSII. In this thesis, the electrostatic factors contributing to the high oxidation potential of P680 are described. PSII oxidizes water in a specialized metal cluster known as the Oxygen Evolving Complex (OEC). The pathways that water can take to enter the relatively hydrophobic region of PSII are described as well. A previous attempt to reverse engineer PSII’s reactions using the protein scaffold of E. coli’s Bacterioferritin (BFR) existed. The oxidation potential of the pigment used for the BFR ‘reaction centre’ was measured and the protein effects calculated in a similar fashion to how P680 potentials were calculated in PSII. The BFR-RC’s pigment oxidation potential was found to be 0.57 V, too low to oxidize water or tyrosine like PSII. We suggest that the observed tyrosine oxidation in BRF-RC could be driven by the ZnCe6 di-cation. In order to increase the efficiency of iii tyrosine oxidation, and ultimately oxidize water, the first potential of ZnCe6 would have to attain a value in excess of 0.8 V. The results were used to develop a second generation of BFR-RC using a high oxidation pigment. The hypervalent phosphorous porphyrin forms a radical pair that can be observed using Transient Electron Paramagnetic Resonance (TR-EPR). Finally, the results from this thesis are discussed in light of the development of solar fuel producing systems.