A faster running speed is associated with a greater body weight loss in 100-km ultra-marathoners

In 219 recreational male runners, we investigated changes in body mass, total body water, haematocrit, plasma sodium concentration ([Na(+)]), and urine specific gravity as well as fluid intake during a 100-km ultra-marathon. The athletes lost 1.9 kg (s = 1.4) of body mass, equal to 2.5% (s = 1.8) of body mass (P < 0.001), 0.7 kg (s = 1.0) of predicted skeletal muscle mass (P < 0.001), 0.2 kg (s = 1.3) of predicted fat mass (P < 0.05), and 0.9 L (s = 1.6) of predicted total body water (P < 0.001). Haematocrit decreased (P < 0.001), urine specific gravity (P < 0.001), plasma volume (P < 0.05), and plasma [Na(+)] (P < 0.05) all increased. Change in body mass was related to running speed (r = -0.16, P < 0.05), change in plasma volume was associated with change in plasma [Na(+)] (r = -0.28, P < 0.0001), and change in body mass was related to both change in plasma [Na(+)] (r = -0.36) and change in plasma volume (r = 0.31) (P < 0.0001). The athletes consumed 0.65 L (s = 0.27) fluid per hour. Fluid intake was related to both running speed (r = 0.42, P < 0.0001) and change in body mass (r = 0.23, P = 0.0006), but not post-race plasma [Na(+)] or change in plasma [Na(+)] (P > 0.05). In conclusion, faster runners lost more body mass, runners lost more body mass when they drank less fluid, and faster runners drank more fluid than slower runners.     

Circles on pommel horse with a suspended aid: mass-centre rotation and hip joint moment

This is the second study of the series, and its aim was to investigate the influence of using the suspended aid on circle kinetics. In addition to the kinematic data recorded for part one (Fujihara & Gervais, 2012), the pommel reaction forces and the force applied from the suspended aid (aid reaction force) were analysed in relation to the motion of a whole-body mass centre. The hip joint moment was also computed by combining all segments in the lower extremities into a single rigid segment. Generally, the use of the aid changed the magnitude of the mass-centre trajectory or horizontal pommel reaction forces but not their patterns. The results also showed that the net hip joint moment was altered during circles with the aid. In summary, a suspended aid can be used as a progression for a variety of goals because it allows gymnasts to practise circles which would not be possible without the aid. When a suspended aid is used, however, practitioners should be aware of the possible kinetic alteration caused by the external force from the aid.     

African American preschool children's physical activity levels in Head Start

The purpose of this study was to describe the physical activity levels of urban inner city preschoolers while attending Head Start, the federally funded preschool program for children from low-income families. Participants were 158 African American children. Their physical activity during Head Start days was measured using programmed RT-3 accelerometers. Results revealed that the children spent the most time in sedentary and light physical activity, while their participation in moderate-to-vigorous physical activities was low. Given the sedentary class format and limited physical space for the Head Start programs observed, we suggest adding a structured physical activity component to Head Start schools to fight the overweight and obesity crisis.     

浅析凝结水的回收与处理方法

合理利用回收处理凝结水,是工业锅炉实现节约能源,发展经济的必要条件。尝试分析锅炉凝结水回收与处理的意义,及凝结水产生的原因和处理方法,进而实现锅炉的高效节能的功效提供了有力的保障。     

Circles with a suspended aid: reducing pommel reaction forces

The aim of this study was to investigate the influence of a suspended aid on the reaction forces during a basic skill on pommel horse. Twenty gymnasts performed three sets of 10 circles with and without a suspended aid on a pommel horse under which two force plates were set. The results confirmed that the suspended aid could reduce the magnitude of the pommel reaction forces during circles while maintaining the general loading pattern. On the left hand, the average and peak forces were attenuated to 0.59 body weight (BW) and 0.85 BW from 0.76 BW and 1.13 BW, respectively. The right hand experienced slightly larger forces with no-aid trials, but the asymmetry between the hands decreased with the aid. Despite a relatively large variability, all gymnasts experienced smaller impact peak forces with the aid. A suspended aid is most commonly used for a beginner gymnast as an introduction to pommel horse exercises. However, this study confirmed that it can also be useful for all levels of gymnasts who would like to practice pommel horse exercises with reduced pommel reaction forces for a purpose such as a progression for learning a new skill, control of training volume, or rehabilitation.     

那一场失约的雪

妈妈把我塞进被窝。“妈妈,真的要下雪吗？”她把毯子一直拉到我的下巴,在我脸上亲了一下。     

禾本科植物幼苗性状的聚类分析

本文用201种禾本科植物幼苗的60个形态和解剖性状进行了聚类分析，将禾本科植物分为四个大类(一级聚合单位)—狐茅类(Festucoid)、黍类(Panicoid)，竹类(Bambusoid)和画眉草类(Eragrostidoid)。这四类基本上与分类系统中的亚科相吻合，只是芦竹亚科植物的幼苗分散聚到了其它类中。推测芦竹亚科是一个比较原始的类群，狐茅亚科、黍亚科和画眉草亚科可能是在芦竹亚科的基础上进化而来的。  除个别种外，大多数同属的种在较低的聚合水平上聚在一起，超族在亚聚合单位中基本上能够反映出来。  研究证明禾本科植物的幼苗性状在禾本科植物分类中具有重要的分类学意义。     

应用电子技术专业人才方案核心要素的构建与实施——似四川职业技术学院为例

文章以四川职业技术学院为例,介绍了应用电子技术专业人才培养方案核心要素：人才培养模式、专业培养目标、课程体系、教学内容、教学模式和评价方式的构建与实施.     

高考乐理模拟试题(九十二)

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新时期高校农业水利工程发展前景初探——以三峡大学为例

采用光沉积-液相化学法调节电子流向，构建了直接Z型TiO₂/Ag/Ag₃PO_{(4 )}(TAAPO)光催化材料.通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)、X射线光电子能谱(XPS)、紫外-可见漫反射光谱仪以及光致发光(PL)光谱仪等手段对其进行表征，并对其在可见光照射下催化降解环丙沙星(CIP)的性能进行了研究.结果表明，当水体pH为3.0,催化剂分散浓度为0.3 g/L,CIP的初始浓度为15 mg/L时，光催化降解体系能够取得最佳的去除效果.在该组条件下，光照120 min CIP的降解率约为99%,并且在经历4个循环后仍然保持了良好的降解效果.在光催化降解CIP的过程中，主要反应活性物种为超氧自由基(·O₂