Zugl.: Mainz, Univ., Diss., 2006

Univ., Diss.--Bayreuth, 2002. / Literaturverz. S. 359 - 369.

A cafeína é um potente estimulante do sistema nervoso central dos animais e vem sendo usada para melhorar o desempenho de cavalos atletas devido a sua propriedade de estímulo da atividade motora e redução da fadiga muscular. O objetivo do presente estudo foi avaliar o perfil eletroencefalográfico de equinos submetidos a cafeína comercial utilizando eletrodos de superfície e biotelemetria. Foram utilizados dois protocolos experimentais. No primeiro protocolo dois equinos (A e B) foram submetidos a cafeína comercial e no segundo protocolo dois animais controle (C e D) foram submetidos a um placebo com solução fisiológica. O EEG obtido dessas situações foi analisado no ambiente Matlab® onde se avaliou os espectros de potência. Os dados foram analisados por One-way ANOVA valores de p < 0,05 usando vários testes estatísticos. A análise do espectro resultante mostrou predominância de frequências nas faixas de 20 Hz e 35 Hz para o animal A; 15 Hz, 20 Hz e 25 Hz para o animal B, essas frequências foram verificadas nos animais antes de serem submetidos à cafeína; quando foram submetidos à cafeína foi observado um pico predominante em 10 Hz em ambos indivíduos. Para os animais controle, a frequência observada foi de 15 Hz e 25 Hz para o animal C e para o animal D as frequências foram 15 Hz, 20 Hz, 30 Hz e 35 Hz. Para ambos os animais submetidos à cafeína os resultados estatísticos comprovaram que houve diferenças entre as médias da densidade espectral de potência dos sinais adquiridos. Para os animais que foram submetidos ao placebo os testes estatísticos demonstraram que não houve diferenças das médias dos espectros constatando que a aplicação do placebo não teve efeito na atividade elétrica cerebral nos equin os estudados. Conclui-se que o EEG registrou um padrão diferenciado para os animais que foram submetidos à cafeína. / Caffeine is a powerful stimulant of the central nervous system of animals and has been used to improve performance in athletic horses due to its property of stimulating motor activity and reduced muscle fatigue. The aim of this study was to evaluate the electroencephalographic pattern of horses undergoing caffeine by the use of surface electrodes and biotelemetry system. Two experimental protocols were carried out. In the first protocol two horses (A and B) were submitted to commercial caffeine and in the second protocol two control horses (C and D) were submitted to a saline placebo. The EEG was obtained and analyzed in Matlab® by evaluating the power spectra. Data were analyzed by one-way ANOVA with p-value <0.05 using several statistical tests. The results of spectrum analysis showed predominance of frequency bands from 20 Hz to 35 Hz for animal A and 15 Hz, 20 Hz and 25 Hz for animal B; these frequencies were observed in the animals before being subjected to caffeine; when they were submitted to caffeine it was observed a predominant peak at 10 Hz in both individuals. For animals used as control the observed frequency was 15 Hz and 25 Hz for animal C; for animal D frequencies were 15 Hz, 20 Hz, 30 Hz and 35 Hz. For both animals submitted to caffeine statistical results showed that there were differences between the means of the power spectral density of signals acquired. For animals that underwent placebo saline statistical tests showed no differences of mean spectra stating that the application of placebo had no effect on brain electrical activity studied in horses. Overall results had shown that the EEG pattern was influenced by caffeine.

No description available.

published_or_final_version / abstract / Physics / Doctoral / Doctor of Philosophy

The following is a comprehensive study of transient and steady-state nonlinear optical properties of semiconductor microcrystals embedded in a glass matrix (semiconductor doped glass). Transient thermal effects which give rise to longitudinal excitation discontinuities (i.e., kinks) that arise from partial sample switching in increasing absorption optical bistability are observed in a doped glass. The transient thermal effects occur on time scales of a few hundred milliseconds. Femtosecond and nanosecond laser pulses are employed to measure time-resolved and steady-state transmission and differential transmission spectra. The measured spectra reveal several beautiful effects which are attributed to the many-particle effects of electron-hole plasma. The spectra reveal: bandgap renormalization, broadening of the tail states and screening of the continuum states, state filling (spectral hole burning), thermalization of nonthermal carrier population distributions, band filling due to carrier relaxation of the thermal and nonthermal distributions, direct electron-hole recombination and long lived (>>100 ps) tail states which are attributed to electron trapping. Absorption edge dynamics discussed in this dissertation span 15 orders of magnitude.

Title: The knowledge, attitudes and use of performance enhancing substances and supplements among male High-school first and second team athletes in the metropolitan area of Cape Town, South Africa. Objective: Pressure to perform and to achieve success is to many high school athletes the overbearing goal and reality. Many are willing to use substances to achieve their goals even at the expense of their health and wellbeing. Four objectives emanated from this research: To determine the most frequently used sport performance enhancing substances and supplements (PESS) by male high school athletes; to evaluate the prevalence and use of PESS; to determine the main sources of information on PESS to determine the knowledge and lastly to determine the perceptions and attitudes of male high school athletes on PESS usage. Design: This study used a prospective cross sectional survey design. A self-administered questionnaire was employed to assess the participant’s knowledge, perceptions, attitude toward and use of PESS. The selected sample was male athletes in high schools in the central metropolitan area in Cape Town that were involved in competitive sports at the first and second team level. Results: One hundred and twenty two male athletes from four schools in the central metropolitan area of Cape Town participated. No serious PESS use was found. The main first choice of reported sources of information regarding PESS was pharmacists (21.3%), biokineticists (16.4%) and the internet (16.4%). The participants’ knowledge, perception and attitude toward the use of PESS was found to be poor. Conclusion: Most athletes reported to gather information from pharmacists (21.3%) and biokineticists which is encouraging since it is expected of these professionals to provide sound advice. It is suggested to create awareness among such professionals regarding use of PESS by this population and to incorporate organizations such as SAIDS and WADA as part of this dissemination of knowledge. The knowledge, perceptions and attitude toward PESS use by male high school athletes appears to be lacking thus indicating the need for more education on PESS.

by Ho Wai Hung. / Thesis (M.Ph.)--Chinese University of Hong Kong, 1988. / Bibliography: leaves 81-83.

No description available.

Univ., Diplomarbeit--Dresden. / Literaturverz. S. 97 - 107.