Technology requirements for post-1985 communications satellites

The technical and functional requirements for commercial communication satellites are discussed. The need for providing quality service at an acceptable cost is emphasized. Specialized services are postulated in a needs model which forecasts future demands. This needs model is based upon 322 separately identified needs for long distance communication. It is shown that the 1985 demand for satellite communication service for a domestic region such as the United States, and surrounding sea and air lanes, may require on the order of 100,000 MHz of bandwith. This level of demand can be met by means of the presently allocated bandwidths and developing some key technologies. Suggested improvements include: (1) improving antennas so that high speed switching will be possible; (2) development of solid state transponders for 12 GHz and possibly higher frequencies; (3) development of switched or steered beam antennas with 10 db or higher gain for aircraft; and (4) continued development of improved video channel compression techniques and hardware

Technology requirements for communication satellites in the 1980's

The key technology requirements are defined for meeting the forecasted demands for communication satellite services in the 1985 to 1995 time frame. Evaluation is made of needs for services and technical and functional requirements for providing services. The future growth capabilities of the terrestrial telephone network, cable television, and satellite networks are forecasted. The impact of spacecraft technology and booster performance and costs upon communication satellite costs are analyzed. Systems analysis techniques are used to determine functional requirements and the sensitivities of technology improvements for reducing the costs of meeting requirements. Recommended development plans and funding levels are presented, as well as the possible cost saving for communications satellites in the post 1985 era

Exercise and amyotrophic lateral sclerosis

© Springer-Verlag 2012Amyotrophic Lateral Sclerosis (ALS) is a progressive and fatal neurodegenerative disease in which much burden is geared towards end-of-life care. Particularly in the earlier stages of ALS, many people have found both physiological and psychological boosts from various types of physical exercise for disused muscles. Proper exercise is important for preventing atrophy of muscles from disuse-a key for remaining mobile for as long as possible-and as long as it is possible to exercise comfortably and safely, for preserving cardiovascular fitness. However, the typical neuromuscular patient features a great physical inactivity and disuse weakness, and for that reason many controversial authors have contested exercise in these patients during years, especially in ALS which is rapidly progressive. There is an urgent need for dissecting in detail the real risks or benefits of exercise in controlled clinical trials to demystify this ancient paradigm. Yet, recent research studies document significant benefits in terms of survival and quality of life in ALS, poor cooperation, small sample size, uncontrolled and short-duration trials, remain the main handicaps. Sedentary barriers such as early fatigue and inherent muscle misuse should be overcome, for instance with body-weight supporting systems or non-invasive ventilation, and exercise should be faced as a potential non-monotonous way for contributing to better health-related quality of life.info:eu-repo/semantics/publishedVersio