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131.
Rising expectations about future demand for new technologies increase the incentives for investments in innovation by enlarging payoffs to successful innovations. How well does this notion of “demand-pull” apply to non-incremental technological change when demand is largely attributable to actions by governments? In this case, inventors of the most important inventions did not respond positively to strong demand-pull policies; filing of highly cited patents declined precipitously just as demand for wind power created a multi-billion dollar market. Three explanations for this apparent inconsistency with the demand-pull hypothesis played a role: (1) the rapid convergence on a single dominant design limited the market opportunity for non-incremental technical improvements; (2) even though the policies implemented were stringent enough to stimulate demand, uncertainty in their longevity dampened the incentives for inventions that were likely to take several years to pay off; and (3) alternative explanations, such as declining R&D funding and weakening presidential engagement on energy, appear to have been important.  相似文献   
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Background:Research on achievement goal orientations in sport has typically relied on the use of variable-centered approaches that tend to overlook population heterogeneity.In this study,we used a person-centered approach to identify subgroups of competitive tennis players according to unique combinations of achievement goal orientations and tested for subgroup differences in motivation and mental toughness.Methods:A sample of 323 competitive tennis athletes(69.35%male)between 15 and 25 years of age(17.60±2.40 years,mean±SD)completed the 3×2 Achievement Goal Questionnaire for Sport,Sport Motivation Scale Ⅱ,and Mental Toughness Index.Latent profile analysis was used to identify unique combinations of achievement goal orientations.Comparisons between latent subgroups on autonomous motivation,controlled motivation,and mental toughness were performed using analysis of variance.Results:Latent profile analysis supported 3 distinct patterns of achievement goal profiles that were primarily distinguishable based on valence of competence(i.e.,approach vs.avoidance).Analyses of variance indicated that athletes who were classified into subgroups that endorsed approach types of goals(regardless of the types of avoidance goals they endorsed)reported higher levels of autonomous motivation and mental toughness.Conclusion:Results indicated that athletes tend to pursue a number of achievement goals collectively rather than in isolation.Although approach goals are more commonly linked to adaptive psychological functioning and positive outcomes,avoidance goals may also be associated with desirable psychological characteristics if they are pursued in conjunction with approach types of achievement goals.  相似文献   
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This study investigates the efficacy of a social skills training program with seven mildly handicapped students across three school settings: regular classroom, special education resource room, and recess. It was found that social skills training generated improvement on both pre-post measures and behavior ratings. Improvements were maintained 2 weeks after treatment was discontinued for seven students. All students' performance generalized from resource room to regular classroom settings; only four students' performance generalized to the recess setting.  相似文献   
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This investigation assessed the effect of dietary nitrate (NO3?) supplementation, in the form of beetroot juice (BR), on repeat-sprint performance in normoxia and normobaric hypoxia. 12 male team-sport athletes (age 22.3 ± 2.6 y, VO2peak 53.1 ± 8.7 mL.kg?1.min?1) completed three exercise trials involving a 10 min submaximal warm-up and 4 sets of cycling repeat-sprint efforts (RSE; 9 × 4 s) at sea level (CON), or at 3000 m simulated altitude following acute supplementation (140 mL) with BR (HYPBR; 13 mmol NO3?) or NO3depleted BR placebo (HYPPLA). Peak (PPO) and mean (MPO) power output, plus work decrement were recorded during the RSE task, while oxygen consumption (VO2) was measured during the warm-up. There were no significant differences observed between HYPBR and HYPPLA for PPO or MPO; however, work decrement was reduced in the first RSE set in HYPBR compared with HYPPLA. There was a moderate effect for VO2 to be lower following BR at the end of the 10 min warm-up (ES = 0.50 ± 0.51). Dietary NO3? may not improve repeat-sprint performance in hypoxia but may reduce VO2 during submaximal exercise. Therefore, BR supplementation may be more effective for performance improvement during predominantly aerobic exercise.  相似文献   
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This study aimed to determine the suitability of the load-velocity relationship to prescribe the relative load (%1RM) in women, as well as to compare the load-velocity profile between sexes and participants with different strength levels. The load-velocity relationship of 14 men (1RM: 1.17 ± 0.19) and 14 women (1RM: 0.66 ± 0.13) were evaluated in the bench press exercise. The main findings revealed that: (I) the load-velocity relationship was always strong and linear (R2 range: 0.987–0.993), (II) a steeper load-velocity profile was observed in men compared to women (Effect size [ES]: 1.09), with men showing higher velocities for light loads (ES: ? 0.81 and ? 0.40 for the y-intercept and 30%1RM, respectively), but women reporting higher velocities for the heavy loads (ES: 1.14 and 1.50 at 90%1RM and 100%1RM, respectively); and (III) while the slope of the load-velocity profile was moderately steeper for weak men compared to their strong counterpart (ES: 1.02), small differences were observed between strong and weak women (ES: ? 0.39). While these results support the use of the individual load-velocity relationship to prescribe the %1RM in the bench press exercise for women, they also highlight the large disparities in their load-velocity profile compared to men.  相似文献   
137.
Abstract

The March 1971 heavyweight championship bout between undefeated black boxers Muhammad Ali and Joe Frazier elicited numerous responses. Ali, because of his brash persona, refusal to be drafted into the Vietnam War, and outspoken criticisms of white racism, had become a potent symbol of 1960s rebellion and Black Power. Frazier, by claiming the heavyweight championship while Ali was banished, cozying up to white politicians, and refusing to criticize the US government, made himself a worthy foil for Ali’s politics. But as the rhetoric surrounding the fight intensified, regarding black masculinity, patriotism, and community pride, one key aspect of the fight opened up debates in a surprising realm: the economics of black athletes and the possibilities and limitations of black capitalism. In an era when black capitalist programmes emerged nationwide, and when African-American athletes took on more vocal roles as community activists, the battles over the bout’s financial promotion became intense. While the boxers took home an unprecedented $2.5 million each for their participation, total revenues reached nearly $30 million. Discussions of the fight’s payout shed light on a wide range of economic issues facing the black community, and some of the unresolved issues in the quest for civil rights.  相似文献   
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