Fluid balance of elite Brazilian youth soccer players during consecutive days of training     

Silva RP  Mündel T  Natali AJ  Bara Filho MG  Lima JR  Alfenas RC  Lopes PR  Belfort FG  Marins JC 《Journal of sports sciences》2011,29(7):725-732

In this study we investigated pre-training hydration status, fluid intake, and sweat loss in 20 elite male Brazilian adolescent soccer players (mean?±?s: age 17.2?±?0.5 years; height 1.76?±?0.05?m; body mass 69.9?±?6.0?kg) on three consecutive days of typical training during the qualifying phase of the national soccer league. Urine specific gravity (USG) and body mass changes were evaluated before and after training sessions to estimate hydration status. Players began the days of training mildly hypohydrated (USG?>?1.020) and fluid intake did not match fluid losses. It was warmer on Day 1 (33.1?±?2.4°C and43.4?±?3.2% relative humidity; P?相似文献   

The Accuracy of Dixon’s Formula for Obtaining Critical F-Values     

James R. Morrow JR.  Kenneth D. Hopkins 《Journal of Experimental Education》2013,81(2):113-115

The F-distribution approximation suggested by Dixon was investigated at various combinations of alpha and degrees of freedom. Tabled values were compared with values computed utilizing the suggested formula. The results indicate that while the formula is not useful in all cases, the adequacy of the approximation generally increases as alpha, v₁, and v₂ increase. It is suggested that the approximation may be utilized when certain restrictions regarding alpha, v1, and v2 are met.  相似文献   

Early Training in Oral Comprehension and Phonological Skills: Results of a Three-Year Longitudinal Study     

Maryse Bianco  Pascal Bressoux  Anne-Lise Doyen  Eric Lambert  Laurent Lima  Catherine Pellenq 《Scientific Studies of Reading》2013,17(3):211-246

A sample of 1,273 4-year-old children were followed for 3 years. The children participated in 1 of 2 comprehension training programs, or in a phonological awareness training program. The comprehension programs explored the possibility of improving young children's oral comprehension in an educational setting. The first focused on the component skills of comprehension; the second involved storybook reading. Phonological awareness and oral language comprehension skills were measured repeatedly in the course of the study. The data were analyzed using multilevel growth-curve models. The results showed that it is possible to improve oral comprehension if the training focuses on its component skills and extends over 2 semesters. When these conditions were met, training effects still existed 9 months after the program had ended. Finally, phonological training improved phonological awareness but not comprehension, and comprehension-skill training improved oral comprehension but not phonological awareness.  相似文献   

Establishment of higher education institutions and new firm entry   总被引：1，自引：0，他引：1  

Rui Baptista  Francisco Lima  Joana Mendonça 《Research Policy》2011,40(5):751-760

The presence of universities has generally been associated with technological entrepreneurship. But what is the real impact of new universities on the levels of firm creation in a region? The present paper uses policy evaluation methodologies and longitudinal data on the establishment of higher education institutions in Portuguese municipalities for the period 1992-2002 to examine its effect on entry rates of new firms in different sectors. We find that the establishment of a new university has a positive and significant effect on subsequent levels of knowledge based firm entry in municipalities, and a negative effect on the levels of entry in other sectors, such as low-tech manufacturing.  相似文献   

Prediction of peak V˙O2 in Children and Adolescents With HIV From an Incremental Cycle Ergometer Test     

Luiz Rodrigo Augustemak de Lima  Diego Augusto Santos Silva  Paulo Cesar do Nascimento Salvador  Carlos Alencar Souza Alves Junior  Priscila Custódio Martins  João Antônio Chula de Castro 《Research quarterly for exercise and sport》2019,90(2):163-171

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竞技体育后备人才培养模式的研究现状与发展趋势     

宋丽华  赵晓光  王福军 《吉林体育学院学报》2010,26(6):18-20

采用文献资料、理论分析、逻辑推理法等对近10年来竞技体育后备人才培养模式的现状进行研究,肯定了竞技体育后备人才培养模式研究中的成绩,指出存在的问题,并分析了今后竞技体育后备人才发展趋势。  相似文献   

Pre-game hydration status, sweat loss, and fluid intake in elite Brazilian young male soccer players during competition     

Da Silva RP  Mündel T  Natali AJ  Bara Filho MG  Alfenas RC  Lima JR  Belfort FG  Lopes PR  Marins JC 《Journal of sports sciences》2012,30(1):37-42

In this study, we assessed the pre-game hydration status and fluid balance of elite young soccer players competing in a match played in the heat (temperature 31.0 ± 2.0 ° C, relative humidity 48.0 ± 5.0%) for an official Brazilian soccer competition. Fluid intake was measured during the match, as were urine specific gravity and body mass before and after the game to estimate hydration status. Data were obtained from 15 male players (age 17.0 ± 0.6 years, height 1.78 ± 0.06 m, mass 65.3 ± 3.8 kg); however, data are only analysed for 10 players who completed the full game. The mean (± s) sweat loss of players amounted to 2.24 ± 0.63 L, and mean fluid intake was 1.12 ± 0.39 L. Pre-game urine specific gravity was 1.021 ± 0.004, ranging from 1.010 to 1.025. There was no significant correlation between sweat loss and fluid intake (r = 0.504, P = 0.137) or between urine specific gravity and fluid intake (r = -0.276, P = 0.440). We conclude that young, native tropical soccer players started the match hypohydrated and replaced about 50% of the sweat lost. Thus, effective strategies to improve fluid replacement are needed for players competing in the heat.  相似文献   

Water-Based Aerobic Training Successfully Improves Lipid Profile of Dyslipidemic Women: A Randomized Controlled Trial     

Rochelle Rocha Costa  Carmen Pilla  Adriana Cristine Koch Buttelli  Michelle Flores Barreto  Priscila Azevedo Vieiro  Cristine Lima Alberton 《Research quarterly for exercise and sport》2018,89(2):173-182

Purpose: This study aimed to investigate the effects of water-based aerobic training on the lipid profile and lipoprotein lipase (LPL) levels in premenopausal women with dyslipidemia. Method: Forty women were randomly assigned to: aquatic training (WA; n = 20) or a control group (CG; n = 20). The WA group underwent 12 weeks of water-based interval aerobic training twice a week at intensities ranging from 9 to 15 on the Borg Scale of Perceived Exertion. Total cholesterol (TC), triglycerides (TG), high- (HDL) and low- (LDL) density lipoprotein, TC/HDL ratio, LPL levels, and peak oxygen consumption (VO₂peak) were evaluated before and after 12 weeks in both groups. Results: The WA group elicited decreases in TC (9%; effect size [ES] = 0.69; 95% CI [0.05, 1.33]), LDL (16%; ES = 0.78; 95% CI [0.13, 1.42]), and the TC/HDL ratio (17%; ES = 1.13; 95% CI [0.46, 1.79]), as well as increases in VO₂peak (10%; ES = 0.64; 95% CI [0.002, 1.27]) and HDL (10%; ES = 0.28; 95% CI [?0.35. 0.90]), without significant changes in TG (ES = 0.16; 95% CI [?0.46, 1.79]) and LPL (ES = 0.36; 95% CI [?0.27, 0.98]) levels. In the CG, no statistically significant changes in any of these variables were found (TC, ES = 0.19, 95% CI [?0.43, 0.82]; LDL, ES = 0.22, 95% CI [?0.40, 0.85]; HDL, ES = 0.05, 95% CI [?0.57, 0.67]; TG, ES = 0.09, 95% CI [?0.53, 0.71]; TC/HDL ratio, ES = 0.20, 95% CI [?0.42, 0.82]; LPL, ES = 0.02, 95% CI [?0.60, 0.64]; VO₂peak, ES = 0.20, 95% CI [?0.42, 0.82]). Conclusion: Water-based interval aerobic training positively affected the lipid profile in premenopausal dyslipidemic women.  相似文献   

Understanding productivity dynamics: A task taxonomy approach     

Tiago Fonseca  Francisco Lima  Sonia C. Pereira 《Research Policy》2018,47(1):289-304

As job markets have been polarizing, firms have been changing their labor inputs. By using matched employer–employee data for Portugal, we examine whether labor market polarization has occurred within or across firms and how labor input upgrades have contributed to overall productivity growth. We develop a firm taxonomy based on worker's occupational data. Firms can be focused on one task – Abstract, Manual or Routine – on a combination of tasks, or none. Results show that Abstract firms are the most productive and their share has increased over time. Manual firms, the least productive, have had a stable share throughout the period. Routine firms have seen their share decline over time. The dynamic decomposition of the estimated productivity reveals that productivity growth is propelled by increased market shares of the most productive incumbents and exiting of the least productive, especially for Abstract firms. Notwithstanding these productivity growth drivers, they fail to avert the productivity stagnation observed in Portugal between 2004 and 2009 due to the overall decline in productivity of incumbent firms, especially Routine. We discuss the policy implications of our results which are relevant to other European economies also lagging behind in terms of knowledge and innovation capabilities.  相似文献   

Archaic schooling,creative schooling     

Lauro de Oliveira Lima 《Prospects》1983,13(2):143-160

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