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Philip K. Porter and Deborah Fletcher

This article uses data from the 1996 Summer Olympic Games and the 2002 Olympic Winter Games to test the predictions of regional input-output models. Real changes associated with these events are insignificant. Nominal measures of demand overstate demand increases and factor price increases absorb the impact of real increases in demand. Nominal changes appear to be limited to hotel prices. Input-output models of a regional economy are often used to predict the impact of short-duration sporting events. Because I-O models assume constant factor prices and technical coefficients between sectors are calibrated from long-run steady-state relations in the regional economy, the predictions greatly overstate the true impact. Because the predictions of these models are increasingly used to justify public subsidies, understanding these deficiencies is crucial.

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Deborah K. Fletcher and Nicolette C. Bishop

This study investigated the effect of a high and low dose of caffeine on antigen-stimulated natural killer (NK) cell (CD3CD56+) activation after prolonged, strenuous cycling, as assessed by the early-activation molecule CD69. In a randomized crossover design, 12 healthy male endurance-trained cyclists cycled for 90 min at 70% VO2peak 60 min after ingesting either 0 (PLA), 2 (2CAF), or 6 (6CAF) mg/kg body mass of caffeine. Whole blood was stimulated with Pediacel (5 in 1) vaccine. A high dose of caffeine (6CAF) increased the number of CD3CD56+ cells in the circulation immediately postexercise compared with PLA (p < .05). For both 2CAF and 6CAF, the geometric mean fluorescence intensity (GMFI) of CD69+ expression on unstimulated CD3CD56+ cells was significantly higher than with PLA (both p < .05). When cells were stimulated with antigen, the GMFI of CD69 expression remained significantly higher with 2CAF than with PLA 1 hr postexercise (p < .05). Although not achieving statistical significance, 6CAF also followed a similar trend when stimulated (p = .09). There were no differences in GMFI of CD69 expression between 2CAF and 6CAF. These results suggest that a high (6 mg/kg) dose of caffeine was associated with the recruitment of NK cells into the circulation and that both a high and low (2 mg/kg) dose of caffeine increased unstimulated and antigen-stimulated NK-cell activation 1 hr after high-intensity exercise. Furthermore, there does not appear to be a dose-dependent effect of caffeine on NK-cell activation 1 hr after prolonged intensive cycling.