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PURPOSE: A cohort of middle-aged and older men and women were followed for an average of 5.5 yr to examine the association between physical fitness, physical activity, and the prevalence of functional limitation. METHODS: The participants received medical assessments between 1980 and 1988 and responded to a mail-back survey regarding functional status in 1990. RESULTS: Among 3495 men and 1175 women over 40 yr of age at baseline, 350 (7.5%) reported at least one functional limitation in daily or household activities at follow-up. The prevalence of functional limitation was higher among women than men. Physically fit and physically active participants reported less functional limitation than unfit or sedentary participants. After controlling for age and other risk factors, the prevalence of functional limitation was lower for both moderately fit (odds ratio = 0.4, 95% CI = 0.2-0.6) and high fit men (odds ratio = 0.3, 95% CI = 0.2-0.4), compared with low fit men. Corresponding figures for women were 0.5 (0.3-0.7) and 0.3 (0.2-0.5) for moderately fit and high fit women. The association between physical activity and functional limitation was similar to the data for physical fitness. CONCLUSIONS: These data support a protective effect of physical fitness and physical activity on functional limitation among older adults and extend this protective effect to middle-aged men and women.  相似文献   
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Higher order sliding mode (HOSM) control design is considered for systems with a known permanent relative degree. In this paper, we introduce the robust Fuller's problem that is a robust generalization of the Fuller's problem, a standard optimal control problem for a chain of integrators with bounded control. By solving the robust Fuller's problem it is possible to obtain feedback laws that are HOSM algorithms of generic order and, in addition, provide optimal finite-time reaching of the sliding manifold. A common difficulty in the use of existing HOSM algorithms is the tuning of design parameters: our methodology proves useful for the tuning of HOSM controller parameters in order to assure desired performances and prevent instabilities. The convergence and stability properties of the proposed family of controllers are theoretically analyzed. Simulation evidence demonstrates their effectiveness.  相似文献   
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In summer 1991 an outbreak of a Salmonella enteritidis epidemic involving about 600 cases of gastroenteritis occurred at one of the leading pharmaceutical companies in southwestern Germany. The main source was a cold fruit soup, in addition Salmonella were isolated from meat strips and a curd cheese which were used for a salad dressing. A total of 2300 contaminated food portions were served resulting in an attack rate of about 25%. The possible origin could have been an asymptomatic Salmonella-positive member of the kitchen personnel who was the only one who was involved with the preparation of all the incriminated foods. A further spread of the epidemic and especially the possible contamination of pharmaceuticals was avoided by the timely and adequate reaction of the company's occupational medical service. This case exemplifies how classical crisis management, "increased initiative on one's own for prevention of infections in all areas of food processing" (Steuer) and finally the cooperation of the company with different institutions of the public health authorities contribute to the control of such a catastrophic scenario.  相似文献   
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One of the most challenging tasks confronting a crime laboratory technician is the fingerprinting and subsequent identification of an unknown homicide or drowning victim whose fingers have been subjected to a long period of exposure to water and the effects of decomposition. If the fingers of the individual have not been exposed to the erosive effects of water and decomposition for a long period of time, they may be allowed to dry, and suitable impressions are often obtainable. In other cases the fingers may have to be removed, with the permission of the Medical Examiners Office, and processed by the Crime Laboratory in an attempt to develop suitable ridge structure for inked impressions or an exact photographic copy of the individual's fingers. In extreme cases the effects of water and decomposition make the fragile ridge structure appear to be nonexistent to the naked eye. The procedure used in this case report, combines the use of cyanoacrylate vapor, commonly called "super glue fuming," and the ninhydrin process in conjunction to develop fragile ridge structure into discernable ridges that are easily seen and photographed for the purpose of making an identification of the individual.  相似文献   
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Evidence for immunologic processes taking part in the pathogenesis of what until now has been called the "essential" form of EPH gestosis is cited. The name of immunogestosis (IG) is introduced. The data of this preliminary study suggest that regular "inoculation" of the female genital tract with allogeneic spermatozoal histocompatibility antigens reduces the incidence of IG. Information about preconceptional sexual habits and contraceptive measures was obtained from 83 selected primigravid patients. Twenty-eight women had mild to moderate IG (Group B);55 did not (Group A). Women in Group B had had less contact with spermatozoa of partners than did women in Group A. Oral contraceptive consumption was less in Group B than in Group A. Women in Group B were younger than women in Group A. All these differences were statistically significant. A new immunoetiologic hypothesis referring to IG, as well as the theoretic and clinical implications arising from it, are discussed. This hypothesis is based on the assumption that spermatozoal histocompatibility antigens can either induce immunologic tolerance or be responsible for the phenomenon of immunologic enhancement in the maternal immunosystem. As the fetus inherits paternal histocompatibility antigens, it is concluded that pre-existing tolerance (or enhancement) exerts an IG-preventive function in a subsequent pregnancy.  相似文献   
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A time-bound hierarchical key assignment scheme is a method to assign time-dependent encryption keys to a set of classes in a partially ordered hierarchy, in such a way that each class can compute the keys of all classes lower down in the hierarchy, according to temporal constraints.  相似文献   
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Reverberating chambers are of recognized relevance in many EMC applications since they allow us to generate a reference electromagnetic statistical field. This paper investigates the electromagnetic field in reverberating chambers. Reverberating chambers are large overmoded cavities wherein a nonstationary electromagnetic field is present. This electromagnetic field is stochastic in nature; therefore, proper analytical tools need to be considered in order to characterize it. We deal with the theoretical aspects related to the characterization of the electromagnetic field inside the chamber and with the application to the case of the reverberating chamber of the Istituto Universitario Navale  相似文献   
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