The environment today

While considerable progress has been made in dealing with air and water pollution, the earth's natural systems seem in difficulty. Scientific knowledge of environmental matters remains inadequate. A massive effort to promote solar energy and a national commitment to energy conservation are needed. The Clean Air Act has important implications for economic growth, and the Environmental Protection Agency should emphasize flexibility of administration, decentralization, and close cooperation with state and local governments. Expanded use of coal presents major uncertainties in human health and atmospheric effects. Increasing emphasis on chemical pollutants requires better societal perception of risks and benefits. New efforts to avoid confrontation on environmental issues are promising. Finally, the protection of life in all its diversity is today's urgent environmental challenge.     

Photovoltaics today and tomorrow

In the next several decades it is expected that the United States and the rest of the nations of the world will greatly expand their consumption of electricity. But many questions will accompany this expansion: Can we build enough generating capacity? Do we have enough energy resources? Can we accommodate centralized and dispersed needs, large and small applications, and the diverse requirements of all sections of the world? And can we increase consumption without increasing environmental degradation? Photovoltaics, which by means of solid-state technology turn photon energy into electricity, can make a substantial contribution toward fulfilling these energy needs. Historically, the drawbacks to photovoltaics have been cost and technological maturity. But more than a decade of research has greatly advanced the technology and has brought it to the point of entering large electricity markets. Advances in the next two decades should make it possible for photovoltaics to become one of the world's preferred technologies for generating electrical energy.     

Parallel supercomputing today and the cedar approach

More and more scientists and engineers are becoming interested in using supercomputers. Earlier barriers to using these machines are disappearing as software for their use improves. Meanwhile, new parallel supercomputer architectures are emerging that may provide rapid growth in performance. These systems may use a large number of processors with an intricate memory system that is both parallel and hierarchical; they will require even more advanced software. Compilers that restructure user programs to exploit the machine organization seem to be essential. A wide range of algorithms and applications is being developed in an effort to provide high parallel processing performance in many fields. The Cedar supercomputer, presently operating with eight processors in parallel, uses advanced system and applications software developed at the University of Illinois during the past 12 years. This software should allow the number of processors in Cedar to be doubled annually, providing rapid performance advances in the next decade.     

Acoustic oscillations in the early universe and today

During its first approximately 100,000 years, the universe was a fully ionized plasma with a tight coupling by Thompson scattering between the photons and matter. The trade-off between gravitational collapse and photon pressure causes acoustic oscillations in this primordial fluid. These oscillations will leave predictable imprints in the spectra of the cosmic microwave background and the present-day matter-density distribution. Recently, the BOOMERANG and MAXIMA teams announced the detection of these acoustic oscillations in the cosmic microwave background (observed at redshift approximately 1000). Here, we compare these CMB detections with the corresponding acoustic oscillations in the matter-density power spectrum (observed at redshift approximately 0.1). These consistent results, from two different cosmological epochs, provide further support for our standard Hot Big Bang model of the universe.     

简论终身体育与高校体育教学

本文通过对终身体育的意义和高校体育现状的分析，就高校体育在如何实现终身体育方面发挥作用提出了自己的论点，以期高校体育教育和终身体育能够有效地接轨。     

论西方休闲体育与竞技体育的融合发展

休闲体育与竞技体育同样兴起于西方,经过各自漫长的发展历程,这两种截然不同的体育形式趋向于融合,竞技休闲化与休闲竞技化是当代体育发展的总特征。一方面,在过去民族主义推动下的传统意义的竞技体育在向生活化、娱乐化的方向发展;另一方面,休闲体育在人类自我发展与完善的基调中,积极引入竞争因素,从而向竞技化方向发展。而无孔不入的商业则促使休闲体育与竞技体育相互渗透与融合。     

学区体育模式：体育强国战略下学校体育与社会体育接轨的进路

实现体育强国梦,学校体育教育必须和身心健康教育、与个人和社会发展联系起来,必须和社会体育接轨融合。需要体现“以人为本”理念,着眼于人的全面和谐、终生发展;增强学生对延伸和拓展科学锻炼的实际功能的再认识,把科学体育锻炼作为相互融合的载体;建立一种以高校为中心辐射到家庭、社区的综合立体保障机制即学区体育模式,有效促进学校体育和社会体育的相互融合,共同发展,达到资源共享、职责明确,形成学校、家庭和社区的合力。