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71.
Integrins are cell surface receptors that mediate adhesion to the extracellular matrix. In this Perspective, we focus on the recent finding that a decrease in the levels of integrins yields fruit flies that retain youthful mobility as they age and display an increased mean life span. We discuss how the reduction of integrin activity might lead to the observed changes. 相似文献
72.
Annie H. Liu Charles A. Rarick Ph.D. 《International Journal of Value-Based Management》1991,4(1):57-67
The ethical foundations for management behavior are examined for the people in Taiwan and from those within the United States. The influences for ethical actions can be traced to Confucian teachings and Christian doctrines. The authors present the philosophical differences between humanism for Chinese people and spiritualism for Christian people in the United States. Comparisons are made on how these principles affect the management behavior within organizations. 相似文献
73.
Monk TH 《Work and stress》1990,4(3):227-236
This review is concerned with how chronobiological results concerning the human circadian timekeeping system ('biological clock'), its response to changes in schedule, and its influence on performance ability can be used to improve shift worker wellbeing, safety and productivity. 相似文献
74.
Environmental Tobacco Smoke: Exposure-Response Relationships in Epidemiologic Studies 总被引:1,自引:0,他引:1
Demonstration of a dose-response relationship for environmental tobacco smoke (ETS) is an important indication of causality. Central to the analysis and interpretation of dose-response relations as described in epidemiological studies is the relationship between dose and exposure. It must be recognized that in studies of ETS we have only surrogate measures of dose, and these surrogate measures (based on exposure) are imperfect. The question-based measures of ETS exposure generally have not been standardized, may have limited validity and reliability, and cannot comprehensively describe total ETS exposure, exposure to individual ETS components, nor doses of biologically relevant agents at target sites. Nevertheless, useful data have been yielded in epidemiologic studies linking ETS exposure to increased respiratory infection and symptoms, reduced lung growth in children, and increased lung cancer in nonsmoking adults. The more consistent exposure-response data for studies on acute health in children may reflect the greater difficulty in measuring exposure in studies of chronic health in adults. 相似文献
75.
Thompson EH 《Omega》1985,16(3):233-242
This paper explores the errors involved in the approximation of both the maximum and sum of two independent Beta random variables, each by another Beta random variable. The principal area of application is the time analysis of PERT networks, and the results are interpreted and discussed in terms of this application. The error was found to be acceptable for the greater part of the range of the parameters involved. The results will help practitioners estimate the mean and standard deviation of the completion time of PERT networks. 相似文献
76.
M.H. Ross 《Long Range Planning》1981,14(3):5-6
A model has been developed to describe the pharmaceutical research and drug innovation process. The model originally served to show the range of results that could arise from research in the field of infectious disease chemotherapy over a sustained period of time. The main goal of the model was to illuminate the risk/reward/time tradeoff faced by management in selecting a particular research strategy. The results obtained with this model were one of several considerations influencing the research strategy decision of CIBA-GEIGY in 1976 to adapt and strengthen its research effort in infectious disease chemotherapy.This model has so far been applied only for the comparative evaluation of infectious disease chemotherapy research strategies. However, there is no conceptual reason why it should be limited to this field of drug research or indeed to pharmaceutical research at all. This type of analysis should be applicable wherever clear, product-oriented research goals can be identified and defined, where some reasonable financial reward can be attached to achieving these goals, and where an assessment—albeit subjective—can be made of the likelihood of achieving these goals. 相似文献
77.
Pollard JH 《Mathematical Population Studies》1989,2(1):1-14
Mortality data are often gathered using 5-year age groups rather than individual years of life. Furthermore, it is common practice to use a large open-ended interval (such as 85 and over) for mortality data at the older ages. These limitations of the data pose problems for the actuary or demographer who wishes to compile a full and accurate life table using individual years of life. The author devises formulae which handle these problems. He also devises methods for handling mortality during the 1st year of life and for dealing with other technical problems which arise in the compilation of the full life table from grouped data. 相似文献
78.
Pekin H 《International migration (Geneva, Switzerland)》1989,27(2):281-293
This paper examines the situation and problems of migration on family structure, with emphasis on family reunification. The study is based on conditions and practices in Western Europe and Mediterranean countries relating to temporary labor migration. Most migrant workers have no intention of settling permanently and return to their country within a few years. The International Labour Office estimated in 1974 that at least 1/2 the migrant workers in Western Europe live without their families. Generally, migrants send for their families only when they are employed, earning adequate wages, and have adequate housing. Some reasons why migrants live apart from their families include 1) the receiving country discourages family immigration because it does not coincide with the economic necessities of migration policy and 2) some sending countries discourage it to ensure that the migrant worker returns to his own country. The main danger arising from family separation is that it frequently leads to the break up of the family. The leading European authorities recognize as a fundamental right the freedom of a migrant worker and his family to lead a normal family life in the receiving country. The author outlines the conditions for admission for residence and employment of migrant spouses and children for the Federal Republic of Germany, France, Belgium, Switzerland, the Netherlands, Sweden, Norway, Austria, Luxembourg, and the United Kingdom. All countries require that the head be in regular employment for some time and be able to provide his family with suitable housing. Other problems concerning the arrival of migrant spouses and children include 1) acquiring employment and social information and counseling, 2) education of children, 3) obtaining vocational training and adaptation and 4) achieving entitlement to social security benefits. The effects of migration in the family context in sending countries include 1) providing activities for migrants to maintain cultural links with their countries of origin and 2) acquiring the nationality of the receiving countries. Countries should facilitate the admission to employment of migrant spouses and children, by maintaining provisions for the reuniting of families and imposing no limits on admission to residence; and 2) by overcome obstacles to admission to employment, by observing existing recommendations. In conclusion, governments should give family cohesion 1st priority, regardless of regulations. 相似文献
79.
To assess the validity and clinical utility of the marital inventory ENRICH, a discriminant validity study was conducted using a national sample of 5039 married couples. The sample was randomly split in order to form a cross-validation group. ENRICH is a multidimensional scale and two types of analysis were conducted to assess the value of these various scales. Results from discriminant analysis indicated that using either the individual scores or couples' scores, happily married couples could be discriminated from unhappily married couples with 85–95% accuracy. These results were cross-validated with a second sample. Using regression analysis, it was clearly demonstrated that background factors account for little of the variance in discriminating happy from unhappily married couples compared to their relationship dynamics, i.e., scale scores. All ENRICH scales except equalitarian roles proved significant, indicating the validity of a multidimensional inventory. 相似文献
80.