火箭飞机点火起飞

它发出的咆哮声有点像是喷气发动机——但不是在公务舱中听到的那种一成不变的低吟．而是真正震耳欲聋的轰鸣。单薄的飞机外形与这种声音相比似乎很不协调．就像是一辆两厢大众小车配上了集装箱货柜车那吓人的气喇叭。喷着耀眼的烈焰．它从美国新墨西哥州Las Cruces机场的跑道上一跃而起．开始陡直地爬升     

Upper extremity augmentation of lower extremity kinetics during countermovement vertical jumps

Twenty-five volleyball players (14 males, 11 females) were videotaped (60Hz) performing countermovement vertical jumps with and without an arm swing. Ground reaction force and video-based coordinate data were collected simultaneously. The resultant joint force and torque at the hip, knee, ankle and shoulder for two trials per subject per condition were computed and normalized. Average kinematic, resultant joint force and torque data were compared using repeated-measures analysis of variance. Larger values were recorded for the vertical velocity of the centre of mass at take-off in the jumps with (mean 2.75, s=0.3m.s-1) versus without (mean 2.44, s= 0.23m.s-1) an arm swing. The jumps with no arm swing produced larger torques at the hip during the first third of the propulsive phase (from zero to maximum vertical velocity of the centre of mass). During the final two-thirds of the propulsive phase, the arm swing augmented hip extensor torques by slowing the rate of trunk extension and placing the hip extensor muscles in slower concentric conditions that favoured the generation of larger forces and resultant joint torques. During the first two-thirds ofthe propulsive phase, knee extensor torque increased by 28% in the jumps with an arm swing, but maintained a relatively constant magnitude in the jumps with no arm swing.     

丰田背后二三事

丰田到底怎么啦? 其实也不是太大的问题.至少不是工程、机械,甚至是质量的问题.如果你像丰田那样能生产出高品质的汽车,你就可以在全球汽车行业中高速前进.尽管汽车已经是人们所熟悉的机械设备,但它也是非常复杂的东西.     

The Effects of Group Supervisor Roles on Practicum Students' Interview Behavior

This study investigated the effects of two supervisory roles (restrictive and nonrestrictive), when used within the small group practicum seminar, on counselor trainees' ability to emit understanding, affective, and exploratory responses in their final counseling interviews at the end of training. These results were compared to those of a control group that did not use a supervisor. Significant differences were observed only in the ability of the trainees to emit understanding responses.     

Human Sexuality Instruction in Counselor Education Curricula

The authors sent a questionnaire assessing curricula on sexual counseling to chairpersons of all counselor education programs in the United States. Results show the current status of sexuality instruction for counselors.     

Restricted Liberty,Parental Choice and Homeschooling

In this paper the authors carefully study the problem of liberty as it applies to school choice, and whether there ought to be restricted liberty in the case of homeschooling. They examine three prominent concerns that might be brought against homeschooling, viz., that it aggravates social inequality, worsens societal conflict and works against the best interests of children. To examine the tensions that occur between parental liberty, children's interests, and state oversight, the authors consider the case of homeschooling in the Dutch context.