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191.
We explore how natural selection acts upon genes for cooperation, altruism and selfishness in an prisoner's dilemma played by family members. A key parameter determining behavior is that parents and children have different expectations of future offspring. Examining asexual and sexually reproducing populations we show that which strategy of cooperation and defection proves be stable depends on the relative reproduction potential of the players and what proportion of the population is young. "Rotten kids" with altruistic parents can be a stable outcome where reproductive success is the goal, and natural selection may lead individuals to care about their unborn progeny. (JEL D10, H31)  相似文献   
192.
Like measures of outcome, measures of implementation are most useful and analytically powerful when measured at client-level and are quantitative. However, high-quality, individual-level, quantitative service utilization data can be expensive, intrusive, or otherwise impractical to obtain. Cruder data--for example, presence versus absence of a given service--are often more feasible to collect, as well as more likely to be available. Consequently, evaluators can benefit by finding ways to better exploit such data at the analysis phase to compensate for shortcomings at the collection phase. This article documents one such instance in which this was done. Specifically, it describes how quantitative, client-level implementation scales were derived from qualitative (categorical) data and used to support a cross-site synthesis of implementation and outcome analyses in a multisite evaluation. It also suggests additional scenarios in which quantitative implementation scales might be derived form qualitative services data.  相似文献   
193.
The authors have developed and tested scale-up methods, based on a simple social network theory, to estimate the size of hard-to-count subpopulations. The authors asked a nationally representative sample of respondents how many people they knew in a list of 32 subpopulations, including 29 subpopulations of known size and 3 of unknown size. Using these responses, the authors produced an effectively unbiased maximum likelihood estimate of the number of people each respondent knows. These estimates were then used to back-estimate the size of the three populations of unknown size. Maximum likelihood values and 95% confidence intervals are found for seroprevalence, 800,000 +/- 43,000; for homeless, 526,000 +/- 35,000; and for women raped in the last 12 months, 194,000 +/- 21,000. The estimate for seroprevalence agrees strikingly with medical estimates, the homeless estimate is well within the published estimates, and the authors' estimate lies in the middle of the published range for rape victims.  相似文献   
194.
When you are exploring your career and where you are headed, it is helpful to consider what aspects of your job turn you on, and of course, those that don't. Energizers are activities that excite and invigorate you or people who lift your heart and inspire you. De-energizers are activities or people who drain you, drag you down, depress you. Make lists of those things that energize and de-energize you either at work or in other situations. Try hard to do something to incorporate or change at least the first five on each list and see if you feel more job and life satisfaction. Responses from 30 participants of a recent Career Choices program are provided to help you get started.  相似文献   
195.
Jannik  G. Timothy 《Risk analysis》1999,19(3):417-426
Many different radionuclides have been released to the environment from the Savannah River Site (SRS) during the facility's operational history. However, as shown by this analysis, only a small number of the released radionuclides have been significant contributors to potential doses and risks to off-site people. This article documents the radiological critical contaminant/critical pathway analysis performed for SRS. If site missions and operations remain constant over the next 30 years, only tritium oxide releases are projected to exceed a maximally exposed individual (MEI) risk of 1.0E-06 for either the airborne or liquid pathways. The critical exposure pathways associated with site airborne releases are inhalation and vegetation consumption, whereas the critical exposure pathways associated with liquid releases are drinking water and fish consumption. For the SRS-specific, nontypical exposure pathways (i.e., recreational fishing and deer and hog hunting), cesium-137 is the critical radionuclide.  相似文献   
196.
Whether pride, necessity, or inattention is at the root, some "slowly boiling" physicians find themselves working harder for fewer compensations of all sorts, and may not be fully cognizant of their circumstances. This article helps to diagnose and manage the health of physicians' practices and/or related enterprises. There are five levels of enterprise health, ranging from success (S-1) to shutdown (S-5), that serve as weather vanes about how the enterprise is adapting to changes in its environment. How should physicians respond to chaos and the threats of deteriorating enterprise health? A five-step approach is offered: (1) Discern what is important; (2) place and keep your program in alignment with those patient interests that will enhance your enterprise viability; (3) keep score with an internal balanced scorecard; (4) manage and shepherd your resources in a manner that demonstrably adds value to patient care; and (5) know the score and use it.  相似文献   
197.
Innovations are either accepted or rejected in large part because of their implementation--sometimes without regard to improvements over existing techniques. By understanding the dynamics of how innovations are adopted and by whom, physician executives will have insight into influencing others. All adopters are not created equal. They fall into five categories, beginning with those who embrace innovation, even seek it out. In any given organization, or the population in general, there are: (1) innovators (2.5 percent); (2) early adopters (13.5 percent); (3) early majority (34 percent); (4) late majority (34 percent); and (5) laggards (16 percent). As these categories imply, each group has specific personalities related to adopting innovations that can be identified and used to implement new policies and procedures. By identifying and encouraging innovators and early adopters to think outside the box and then gaining critical mass through the early majority, who also act as opinion leaders, organizations can accelerate the pace of adopting innovations. New processes are adopted when opinion leaders initiate new practices, whose results can be tangibly discerned by the majority of adopters.  相似文献   
198.
199.
Systematic and critical evaluation, using food balance sheets, census population data, government surveys, food composition statistics, and estimates of the population's biological requirements, shows that the realized improvements in food supplies in India of the past five decades, while beneficial, have been insufficient to meet the nutritional needs of the average person in a population that grew from less than 350 million to nearly one billion during this period. The improvements also fall significantly short of meeting the needs of the clinically malnourished. Present per capita dietary energy intakes range from as high as 95 percent to as low as 50 percent of daily requirements. Additionally, comparison of past and present diets shows that as the composition of the diet has changed with time, its nutritional quality for many has deteriorated despite an apparent increase in overall food quantity. This has come about from changes in the production system that have emphasized wheat and rice crops at the expense of more nutritional pulses and coarse grains, and from widespread poverty that leaves high-quality animal foods beyond the means of most.  相似文献   
200.
Return migration: changing roles of men and women   总被引:1,自引:0,他引:1  
The study concerns Greek returnees from the Federal Republic of Germany and explores changes in task sharing behaviour and gender role attitudes resulting from changes in cultural environments.
A group of return migrants was compared with a group of non-migrants, both living in villages in the District of Drama, Greece. Groups were interviewed to investigate the extent to which each spouse shared house tasks as well as their attitudes towards gender roles in the family.
The data were factor analysed and a t-test was used to determine any differences between the groups. In addition to demographic variables, those concerning the "time lived abroad" and the "number of years in Greece" after return were inserted into a series of regression analyses for the purpose of explaining task sharing and gender role attitudes.
The results showed that: (a) task sharing of return migrants differs from on-migrants with respect to tasks which are peripheral to house organization. It seems that migrants' task sharing behaviour changes to a certain degree as a result of their changing socio-cultural environments. Results also suggest that migrant husbands and wives either take on new patterns of behaviour or maintain traditional ones only when these are congruent with the financial aims of the family or can be integrated into living conditions in Greece upon return. (b) Lack of differences between groups in an Attitude Questionnaire suggest that gender role attitudes have changed for both migrants and non-migrants over the last 15 to 20 years, although for different reasons and the different conditions under which these groups had lived.  相似文献   
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