Effect of countermovement on elbow joint extension power-load characteristics

The aim of the present study was to examine elbow joint extension power-load characteristics with and without a countermovement. Eight male participants performed maximal elbow extensions with and without a countermovement against different loads (0, 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0 kg). Electromyographic activity of the lateral and long heads of the triceps brachii and the biceps brachii muscles was recorded. The average joint power in the concentric phase was significantly enhanced in the countermovement condition at all loads except for 0 kg. The optimal load for the maximal joint power was greater in the countermovement (7.5 kg) than in the no countermovement condition (5.0 kg). Electromyographic activity was unchanged over the intensities and conditions. Our results suggest that the optimal load for the maximal joint power depends on the type of action (i.e. with or without a counter-movement), and that the enhanced joint power in the countermovement condition is due primarily to the storage and utilization of elastic energy.     

ATriple Iron triathlon leads to a decrease in total body mass but not to dehydration

A loss in total body mass during an ultraendurance performance is usually attributed to dehydration. We identified the changes in total body mass, fat mass, skeletal muscle mass, and selected markers of hydration status in 31 male nonprofessional ultratriathletes participating in a Triple Iron triathlon involving 11.4 km swimming, 540 km cycling and 126.6 km running. Measurements were taken prior to starting the race and after arrival at the finish line. Total body mass decreased by 1.66 kg (SD = 1.92; -5.3 kg to +1.2 kg; p < .001), skeletal muscle mass by 1.00 kg (SD = 0.90; -2.54 kg to +2.07 kg; p < .001), and fat mass by 0.58 kg (SD = 0.78; -1.74 kg to +0.87 kg; p < .001). The decrease in total body mass was associated with the decrease in skeletal muscle mass (r = .44; p < .05) and fat mass (r = .51; p < .05). Total body water and urinary specific gravity did not significantly change. Plasma urea increased significantly (p < .001); the decrease in skeletal muscle mass and the increase in plasma urea were associated (r = .39; p < .05). We conclude that completing a Triple Iron triathlon leads to decreased total body mass due to reduced fat mass and skeletal muscle mass but not to dehydration. The association of decrease in skeletal muscle mass and increased plasma urea suggests a loss in skeletal muscle mass.     

Kinematic differences of elite and high-performance tennis players in the cross court and down the line forehand

This study identified and compared the full body kinematics of different skill levels in the forehand groundstroke when balls were hit cross court and down the line. Forty-three three-dimensional retroreflective marker trajectories of six elite and seven high-performance players were recorded using an eight-camera 400 Hz, Vicon motion analysis system. The six highest horizontal velocity forehands with reliable kinematics of all participants were analysed for each specific situation (a total of 156 analysed shots). Significant differences (p < 0.01) and large effect sizes were observed between elite and high-performance players in linear velocity of the shoulder (2.0 vs. 1.2 m/s), angular velocity of the pelvis (295 vs. 168 degrees/s), and angular velocity of the upper trunk (453 vs. 292 degrees/s) at impact. The elite group showed a tendency towards higher racquet velocities at impact (p < 0.05). No significant differences were found in angular displacement of the racquet, hip alignment, or shoulder alignment at the completion of the backswing; nor did angular displacement vary significantly at impact. Irrespective of the group, different shoulder, hip, and racquet angles were found at impact, depending on the situation. The results should assist coaches when striving to improve their players' forehand.     

Three Cases of Lead Toxicity Associated with Consumption of Ayurvedic Medicines

Ayurveda is a traditional form of medicine used by majority of the Indians. Here we report three cases of lead toxicity, following intake of Ayurvedic medicines. Three patients presented with blood lead levels (BLLs) of 122.4, 115 and 42.8 μg/dl respectively at the time of hospitalization. The first case was chelated with D- penicillamine, the second with calcium disodium ethylene diamino tetra acetate (EDTA) and the third with environmental intervention and education. Associated Ayurvedic products were collected from patients and analyzed for metallic concentration. Cessation of Ayurvedic medication along with chelation, nutritional intervention and education, reduced the BLL to 27.4 μg/dl in the first case after 1 year, 21.1 μg/dl after 9 months in the second and 18.2 μg/dl after 6 months in the third case.     

Perceived efficacy and attitudes towards genetic science and science governance

Arguments for public involvement in science and technology are often based on ideas of developing a more capable public and the assumed effects this may have for science. However, such a relationship is yet to be sufficiently explored and recent work indicates that a more involved public may have counterintuitive effects. Using nationally representative survey data for the U.K. and Northern Ireland, the effects of the public's own beliefs about involvement are explored. Developing the concept of "belief in public efficacy," findings suggest those who believe that the public might be able to affect the course of decision making have less approving attitudes towards future applications of genetic science; however, an individual's political efficacy does not significantly influence these attitudes. Furthermore, political efficacy and belief in public efficacy have some distinct and opposing relationships with the principles of governance people prefer. Overall, findings provide support for suggestions that it is simplistic to consider increasing public involvement as a way of increasing the approval of risky new technologies.     

美国加州:阳光照耀的留学生活(三) 母语和韩国白领李尚美

与此女的认识过程显然要轻松许多,原因是我能够在一定程度上使用她的母语。除了课堂以外,和她一起工作的经历,也成了我宝贵的留学回忆。她便是赴美进修的韩国白领李尚美。     

美国加州：阳光照耀的留学生活

在阳光照耀的美国加州,他生活了五个年头.除了学习.他也打过工,谈过恋爱,积累了众多在美国学习、生活和工作的经验,美国的大学里,聚集了众多来自世界各地的留学生.在这样一处充满世界色彩的地方,置身其中,会有着怎样的独特经历呢?应《课堂内外》高中版特邀,Edwin&#183;T记录下他的留学生活,为可能或者梦想去美国留学的高中生,讲述他的种种感受。从本期开始,本刊将分多期连载该文。     

The most amazing 24 hours

In this column, a mother shares the story of her son's birth with her prenatal yoga instructor. The mother was able to work with her labor, was well supported by her husband and doula, and negotiated successfully with the hospital staff to have a safe, healthy birth. She describes how difficult labor is and the ways in which comfort and support strategies help women manage contractions.     

最好的时光

最好的时光,浸润在槐花香中,曾经就装在我一伸手就摸得到的右裤袋里。     

Approaches to teaching in mainstream and separate postsecondary classrooms

The study examined attitudes toward teaching reported by university instructors who normally teach hearing students (with the occasional deaf or hard of hearing student) and by instructors who normally teach deaf and hard of hearing students at the same institution. Overall, a view of instruction as information transmission was associated with a teacher-focused approach to instruction, whereas viewing instruction as a means of promoting conceptual change was associated with a student-focused approach. Instructors in mainstream classrooms were more oriented toward information transmission than conceptual change, whereas instructors experienced in separate classrooms for deaf and hard of hearing students reported seeking to promote conceptual change in students and adopting more student-focused approaches to teaching. These results are consistent with previous findings concerning instructors' approaches to teaching and deaf and hard of hearing students' approaches to learning, and may help explain recent findings regarding student outcomes in separate versus mainstream secondary classrooms.