排序方式： 共有67条查询结果，搜索用时 15 毫秒
41.
42.
David Maughan Brown 《Higher Education》2000,40(2):163-181
Over the course of its ninety-yearhistory a great deal of time and energy has beendevoted at the University of Natal to trying tounderstand the best way to administer and manage aunitary University whose two main campuses are fiftymiles apart. In the early 1990s, after decades ofgradual separation of the campuses, the massivechanges taking place in South Africa, as experiencedin Higher Education, prompted a major review of themanagement, administrative and committee structureswithin the University. This review, whoserecommendations were accepted and implemented,advocated a formal process of administrative andbudgetary devolution to the two campuses in Durban andPietermaritzburg. Five years later, in the face offurther external pressures, a new review recommendedthat the devolution be reversed and a stronglycentralised structure be put in place. Thisrecommendation, in turn, was approved and implemented. This article outlines the reasoning behind both setsof recommendations and explores the pros and cons fora multi-campus university of both centralisation anddevolution in the light of the experience of auniversity which has gained first-hand knowledge ofboth alternatives in less than a decade. 相似文献
43.
前言 ２０世纪５０年代以来，人们发现肠里葡萄糖的存在促进钠的转运（Ｒｉｋｌｉｓ＆Ｑｕａｓｔｒｅｌ，１９５８），这个里程碑式的发现引发口服补水溶液配方的产生。为满足水、碳水化合物和电解质最大限度的吸收，精确配制这些溶液的问题激起了相当多的科学研究和讨论。 口服补水溶液一直是由葡萄糖、蔗糖、果糖、多精、谷物淀粉或由这些糖混合，并添加不同种类的电解质（如钢、氯、钾、柠檬酸盐、碳酸氢盐），而配制成低渗至高渗的溶液。这些溶液在十二指肠空肠、回肠和结肠的吸收。已在兔子、鼠、狗、猫和人身上得到了测试。 大多数的… 相似文献
44.
45.
Exercise in the heat poses a formidable challenge to the body's ability to control its internal environment due to the high rates of metabolic heat production and heat gain by physical transfer from the environment. In an attempt to restrict the rise in core temperature, an increased rate of sweat secretion onto the skin is invoked. This may limit the rise in core temperature, and can prolong the time before a limiting temperature is attained, but it does so at the cost of a loss of body water and electrolytes. The effects of the diminished blood volume are offset to some extent by cardiovascular adaptations, including an increased heart rate and an increased peripheral resistance, but these are insufficient to maintain functional capacity when blood volume is reduced. Prior dehydration will impair performance in both prolonged exercise and short-term high-intensity exercise. Athletes living and training in the heat may experience chronic hypohydration due to inadequate replacement of fluid losses. The negative consequences of exercise in the heat are attenuated to some extent by a period of adaptation, and by the ingestion of water or other appropriate fluids. Optimum fluid replacement strategies will depend on the exercise task, the environmental conditions and the individual physiological characteristics of the athlete. Manipulation of pre-exercise body temperature can also influence exercise performance and may be a strategy that can be used by athletes competing in stressful environments. 相似文献
46.
Fluid and electrolyte balance in elite male football (soccer) players training in a cool environment
There are few data in the published literature on sweat loss and drinking behaviour in athletes training in a cool environment. Sweat loss and fluid intake were measured in 17 first-team members of an elite soccer team training for 90 min in a cool (5°C, 81% relative humidity) environment. Sweat loss was assessed from the change in body mass after correction for the volume of fluid consumed. Sweat electrolyte content was measured from absorbent patches applied at four skin sites. Mean (?± s) sweat loss during training was 1.69?±?0.45 l (range 1.06?-?2.65 l). Mean fluid intake during training was 423?±?215 ml (44?-?951 ml). There was no apparent relationship between the amount of sweat lost and the volume of fluid consumed during training (r 2 = 0.013, P = 0.665). Mean sweat sodium concentration was 42.5?±?13.0 mmol?·?l?1 and mean sweat potassium concentration was 4.2?±?1.0 mmol?·?l?1. Total salt (NaCl) loss during training was 4.3?±?1.8 g. The sweat loss data are similar to those recorded in elite players undergoing a similar training session in warm environments, but the volume of fluid ingested is less. 相似文献
47.
48.
In the absence of any food or fluid intake during the hours of daylight during the month of Ramadan, a progressive loss of body water will occur over the course of each day, though these losses can be completely replaced each night. Large body water deficits will impair both physical and cognitive performance. The point at which water loss will begin to affect performance is not well defined, but it may be as little as 1-2% of body mass. For resting individuals in a temperate environment, the water loss that occurs during a day without food or fluid will typically amount to about 1% of body mass by the time of sunset. This small loss of body water is unlikely to have a major adverse effect on any aspect of physical or cognitive performance. Larger body water losses will occur, however, in hot weather or if exercise is undertaken. Performance in events lasting about 1 hour or longer may be impaired in the absence of fluid intake during the event. In weight-category sports, there may be difficulties due to the impossibility of restoring body water content between the weigh-in and competition, and athletes will require alternative strategies. Where more than one competition or training session takes place in a single day and where substantial fluid losses are incurred, recovery will be impaired by the absence of fluid intake. 相似文献
49.
50.