4 resultados para Refrigeration and refrigerating machinery

em Brock University, Canada


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Dorothy Rungeling was born in 1911 and raised in Fenwick, Ontario, by her adopted mother, Ethelwyn Wetherald. After graduating high school, she attended Fort Erie business College. She worked briefly in Toronto and then Hamilton, but eventually took a job with Brown Brothers’ Nursery in Pelham to be closer to home. Dorothy pursued many interests, learning to play the violin, saxophone and clarinet. She met her husband Charles at a local dance where she was playing. In 1939, they opened an automobile and farm machinery business in Welland. In their spare time, they were active in skeet and trap shooting, for which Dorothy won many trophies. In the early 1940s, Dorothy developed a passion for horses, training and showing them in addition to teaching riding at the Welland Riding Club, as well as judging at horse shows. By the late 1940s her interest in horses was waning, but she soon after discovered and pursued a new interest: flying. She joined the Welland Flying Club, obtained a flying licence, and in 1949 purchased her first plane. She proceeded to obtain a Commercial Pilot Licence in 1951, an Instructor’s Licence in 1953, and a Senior Commercial Licence in 1954. She participated in many air races in the 1950s, including the All Women’s International Air Races, the Women’s Transcontinental Air Races, and the Canadian Governor-General’s Cup Air Race. Some of the most notable races were the 1954 International Air Race, where Dorothy met with President Batista of Cuba, and the Governor-General’s Cup Air Race, where she won 1st place in 1953 and 1956 (and was the only woman competing). In 1958, she was also the first Canadian woman to solo pilot a helicopter. That same year she obtained her Airline Transport Licence. She also wrote several articles on aviation, contributing to publications such as Canadian Aviation and Air Facts, a U.S. aviation magazine. In addition to these articles, Dorothy authored several books about her life, as well as a selection of poems and articles by Ethelwyn Wetherald. As planes became more expensive, Dorothy spent less time flying, instead pursuing an interest in sailing. She and her husband bought a sailboat and became members of the Niagara-on-the-Lake Sailing Club. In 2003, Dorothy was awarded the Order of Canada for her accomplishments. She also wrote a regular column for the Voice of Pelham in 2012-2013, called A Century in Pelham. Dorothy celebrated her 100th birthday in 2011, and remains an active member of the community.

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Six lefthanded artist-educators were interviewed to attempt to discover any patterns t6 their perceptions and experiences. Artists have their own culture and priorities. According to the literature, lefthanded people appear more likely to suffer from dyslexia, allergies, asthma and other auto-immune diseases as well as machinery and equipment injuries. Patterns emerging suggested that lefthanded people indeed suffer more from dyslexia. More startling was the distinct possibility that many artists have traumatic childhood histories. This would commonly include negative school experiences, and for a significant number sexual assault, perceived or actual abandonment by parents, and/or consistently low selfesteem. The researcher discovered possible reasons why creative people frequently have problems at school, why they tend to be rebellious and anti-establishment oriented, how many of them perceive societal rules, and why they are more likely to be lefthanded. These characteristics all have significant implications for art school administrators.

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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.

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The active metabolite of vitamin A, retinoic acid (RA), is involved in memory formation and hippocampal plasticity in vertebrates. A similar role for retinoid signaling in learning and memory formation has not previously been examined in an invertebrate species. However, the conservation of retinoid signaling between vertebrates and invertebrates is supported by the presence of retinoid signaling machinery in invertebrates. For example, in the mollusc Lymnaea stagnalis the metabolic enzymes and retinoid receptors have been cloned from the CNS. In this study I demonstrated that impairing retinoid signaling in Lymnaea by either inhibiting RALDH activity or using retinoid receptor antagonists, prevented the formation of long-term memory (LTM). However, learning and intermediate-term memory were not affected. An additional finding was that exposure to constant darkness (due to the light-sensitive nature of RA) itself enhanced memory formation. This memory-promoting effect of darkness was sufficient to overcome the inhibitory effects of RALDH inhibition, but not that of a retinoid receptor antagonist, suggesting that environmental light conditions may influence retinoid signaling. Since RA also influences synaptic plasticity underlying hippocampal-dependent memory formation, I also examined whether RA would act in a trophic manner to influence synapse formation and/or synaptic transmission between invertebrate neurons. However, I found no evidence to support an effect of RA on post-tetanic potentiation of a chemical synapse. Retinoic acid did, however, reduce transmission at electrical synapses in a cell-specific manner. Overall, these studies provide the first evidence for a role of RA in the formation of implicit long-term memories in an invertebrate species and suggest that the role of retinoid signaling in memory formation has an ancient origin.