Health-related fitness knowledge growth in middle school years: Individual- and school-level correlates

BackgroundHealth-related fitness knowledge (HRFK) has been an essential concept for many health and physical education programs. There has been limited understanding and longitudinal investigation on HRFK growth. This longitudinal study examined HRFK growth and its individual- and school-level correlates in middle school years under 1 curriculum condition: Five for Life.MethodsParticipants were 12,044 students from 47 middle schools. Data were collected at both individual/participant and school/institution levels. Individual-level variables included gender, grade, and HRFK test scores. School-level variables included percentage of students receiving free and reduced meals (FARM), student-to-faculty ratio for physical education, and school academic performance (SAP). We used hierarchical linear modeling to examine HRFK 3-year growth in relation to individual- and school-level correlates.ResultsThe average HRFK score at 6th grade for females was 42.81% ± 1.32%. The predicted HRFK growth was 17.06% ± 1.02% per year, holding other factors constant. A 1-standard deviation increase in FARM correlated with a 14.68%-point decrease in predicted test score (p = 0.02). A 1-standard deviation increase in SAP was associated with an 11.90%-point increase in HRFK score. Males had a significantly lower growth rate than females during the middle school years (0.78%/year, p = 0.02).ConclusionThe result showed that both individual- and school-level variables such as gender, FARM, and SAP influenced HRFK growth. Educators should heed gender differences in growth curves and recognize the correlates of school-level variables.     

酒店行业员工高流动率问题探讨——以泉州市为例

对泉州市部分酒店的员工流动情况进行调查,同时探讨员工高流动率的弊端。认为酒店行业员工高流动率的成因是:聘用人员多数为职业探索阶段的年轻人,社会对酒店行业的偏见,薪酬水平较低等。提出帮助员工制定职业生涯规划,改进薪酬制度,加强员工的沟通交流,培育企业文化的策略。     

光照强度对七子花苗期光合蒸腾特性的影响

对光照强度对七子花苗期光合、蒸腾特性的影响进行了研究,得到如下结果:净光合速率最适温度为25～30℃,高光合有效辐射和高温下光抑制加剧。蒸腾速率随着温度的升高而增大,在同一温度下高光合有效辐射使得蒸腾速率下降。29℃下饱和光强为890μmol m~(-2)s~(-1),表观量子效率为0.0325,光补偿点为44μmol m~(-2) s~(-1),随着光合有效辐射的增强,气孔阻力减小,高光合有效辐射下,气孔阻力有所上升,蒸腾速率与气孔阻力高度负相关。在29℃的饱和光强下,羧化效率为0.0351,CO_2补偿点为173μmol mol~(-1),低于或高于饱和光强,羧化效率下降,CO_2补偿点升高。     

不同品种黄鳝怀卵量的比较

分别检查深黄大斑鳝和青黄斑鳝的怀卵量 ,结果发现深黄大斑鳝的怀卵率和怀卵强度均高于青黄斑鳝 ;深黄大斑鳝和青黄斑鳝各体长段间怀卵强度差异的不显著 ;深黄大斑鳝 2 5 .1～ 3 0 .0cm、3 5 .0～ 3 9.0cm段分别与青黄斑鳝 14 .0～ 2 0 .0cm、3 0 .1～ 3 5 .0cm和 2 5 .1～ 3 0 .0cm段黄鳝怀卵强度存在显著差异 .     

江苏省高等教育对经济增长贡献率的估算及分析

采用柯布-道格拉斯生产函数构造的模型,测算江苏省教育通过提高劳动者素质对经济增长的贡献率。结果表明,江苏省教育对经济发展有良好的促进作用,但是高等教育对经济增长的贡献率较低,江苏省仍应重视和处理好高等教育发展与经济增长的关系。     

从刻蚀电路板废液中制取硫酸铜的工艺研究

研究了以刻蚀电路板废液为原料制取硫酸铜的工艺条件。探讨了Fe3 的干扰,不同的pH以及不同浓度的NaOH和H2SO4对产品质量的影响。结果表明:采用15%~20%NaOH与20%H2SO4可使产品的回收率达92%,产品纯度可达98%。     

竞技健美操赛前模拟比赛心率变化分析

以心率指标来反映竞技健美操的运动强度。对参加2008年全国锦标赛的运动员进行赛前模拟比赛的心率测试。结果显示：最大心率百分比都在80％以上。运动中的心率变化跟专业级别没有差异性（P〉0．05）,跟年龄有显著的差异性（P〈0．05）。因此在训练中,训练的方式跟专业级别以及年龄相联系,并可运用心率指标进行监控。     

北京奥运会女子举重比赛成败率与试举方案的统计与分析

通过录像观察法、文献资料法、专家访谈法、数理统计方法对2008年北京奥运会女子举重7个级别的全部赛事成败率进行了技术统计分析,结果表明本届北京奥运会女子举重试举成功率比上届有了大幅度的提高;抓举比赛中的后掉次数比前掉次数高;挺举的上挺失败次数高于下蹲翻失败次数;北京奥运会女子举重的试举方案比上届增多;同时,对各国运动员试举技术失败的原因进行了分析表明,运动员技术发挥不稳定、实力不足和比赛心理素质不好是造成试举失败的主要原因。     

Objective and subjective methods for quantifying training load in wheelchair basketball small-sided games

The aim of the present study was to analyse the training load in wheelchair basketball small-sided games and determine the relationship between heart rate (HR)-based training load and perceived exertion (RPE)-based training load methods among small-sided games bouts. HR-based measurements of training load included Edwards’ training load and Stagno’s training impulses (TRIMP_MOD) while RPE-based training load measurements included cardiopulmonary (session RPEres) and muscular (session RPEmus) values. Data were collected from 12 wheelchair basketball players during five consecutive weeks. The total load for the small-sided games sessions was 67.5 ± 6.7 and 55.3 ± 12.5 AU in HR-based training load (Edwards’ training load and TRIMP_MOD), while the RPE-based training loads were 99.3 ± 26.9 (session RPEres) and 100.8 ± 31.2 AU (session RPEmus). Bout-to-bout analysis identified greater session RPEmus in the third [P < 0.05; effect size (ES) = 0.66, moderate] and fourth bouts (P < 0.05; ES = 0.64, moderate) than in the first bout, but other measures did not differ. Mean correlations indicated a trivial and small relationship among HR-based and RPE-based training loads. It is suggested that HR-based and RPE-based training loads provide different information, but these two methods could be complementary because one method could help us to understand the limitations of the other.     

Effects of heat acclimation on hand cooling efficacy following exercise in the heat

This study examined the separate and combined effects of heat acclimation and hand cooling on post-exercise cooling rates following bouts of exercise in the heat. Seventeen non-heat acclimated (NHA) males (mean ± SE; age, 23 ± 1 y; mass, 75.30 ± 2.27 kg; maximal oxygen consumption [VO₂ max], 54.1 ± 1.3 ml·kg^?1·min^?1) completed 2 heat stress tests (HST) when NHA, then 10 days of heat acclimation, then 2 HST once heat acclimated (HA) in an environmental chamber (40°C; 40%RH). HSTs were 2 60-min bouts of treadmill exercise (45% VO₂ max; 2% grade) each followed by 10 min of hand cooling (C) or no cooling (NC). Heat acclimation sessions were 90–240 min of treadmill or stationary bike exercise (60–80% VO₂ max). Repeated measures ANOVA with Fishers LSD post hoc (α < 0.05) identified differences. When NHA, C (0.020 ± 0.003°C·min^?1) had a greater cooling rate than NC (0.013 ± 0.003°C·min^?1) (mean difference [95%CI]; 0.007°C [0.001,0.013], P = 0.035). Once HA, C (0.021 ± 0.002°C·min^?1) was similar to NC (0.025 ± 0.002°C·min^?1) (0.004°C [?0.003,0.011], P = 0.216). Hand cooling when HA (0.021 ± 0.002°C·min^?1) was similar to when NHA (0.020 ± 0.003°C·min^?1) (P = 0.77). In conclusion, when NHA, C provided greater cooling rates than NC. Once HA, C and NC provided similar cooling rates.