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141.
We experimentally compare fast and slow decisions in a series of experiments on financial risk taking in three countries involving over 1700 subjects. To manipulate fast and slow decisions, subjects were randomly allocated to responding within 7 seconds (time pressure) or waiting for at least 7 or 20 seconds (time delay) before responding. To control for different effects of time pressure and time delay on measurement noise, we estimate separate parameters for noise and risk preferences within a random utility framework. We find that time pressure increases risk aversion for gains and risk taking for losses compared to time delay, implying that time pressure increases the reflection effect of Prospect Theory. The results for gains are weaker and less robust than the results for losses. We find no significant difference between time pressure and time delay for loss aversion (tested in only one of the experiments). Time delay also leads to less measurement noise than time pressure and unconstrained decisions, and appears to be an effective way of decreasing noise in experiments.  相似文献   
142.
Since third sector research emerged as a full-fledged interdisciplinary academic field during the late 1980s, a separation has usually been maintained—in common with many other social science disciplines—between communities of researchers who are primarily concerned with the study of the third sector in rich Western countries and those who work on the third sector in the so-called developing world. Whilst internationally focused researchers tend to use the language of ‘non-governmental organizations’, those in domestic settings usually prefer the terms ‘non-profit organization’ or ‘voluntary organization’, even though both subsectors share common principles and are equally internally diverse in terms of organisations and activities. Whilst there has long been common-sense logic to distinguishing between wealthier and poorer regions of the world based on differences in the scale of human need, the ‘developed’ versus ‘developing’ category can also be criticised as being rather simplistic and unhelpfully ideological. As the categories of ‘developing’ and ‘developed’ countries become less clear-cut, and global interconnectedness between third sectors and their ideas grows, this paper argues that we need to reconsider the value of maintaining these parallel worlds of research, and instead develop a more unified approach.  相似文献   
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144.
The use of thimerosal preservative in childhood vaccines has been largely eliminated over the past decade in the United States because vaccines have been reformulated in single‐dose vials that do not require preservative. An exception is the inactivated influenza vaccines, which are formulated in both multidose vials requiring preservative and preservative‐free single‐dose vials. As part of an ongoing evaluation by USFDA of the safety of biologics throughout their lifecycle, the infant body burden of mercury following scheduled exposures to thimerosal preservative in inactivated influenza vaccines in the United States was estimated and compared to the infant body burden of mercury following daily exposures to dietary methylmercury at the reference dose established by the USEPA. Body burdens were estimated using kinetic parameters derived from experiments conducted in infant monkeys that were exposed episodically to thimerosal or MeHg at identical doses. We found that the body burden of mercury (AUC) in infants (including low birth weight) over the first 4.5 years of life following yearly exposures to thimerosal was two orders of magnitude lower than that estimated for exposures to the lowest regulatory threshold for MeHg over the same time period. In addition, peak body burdens of mercury following episodic exposures to thimerosal in this worst‐case analysis did not exceed the corresponding safe body burden of mercury from methylmercury at any time, even for low‐birth‐weight infants. Our pharmacokinetic analysis supports the acknowledged safety of thimerosal when used as a preservative at current levels in certain multidose infant vaccines in the United States.  相似文献   
145.
The use of large-dimensional factor models in forecasting has received much attention in the literature with the consensus being that improvements on forecasts can be achieved when comparing with standard models. However, recent contributions in the literature have demonstrated that care needs to be taken when choosing which variables to include in the model. A number of different approaches to determining these variables have been put forward. These are, however, often based on ad hoc procedures or abandon the underlying theoretical factor model. In this article, we will take a different approach to the problem by using the least absolute shrinkage and selection operator (LASSO) as a variable selection method to choose between the possible variables and thus obtain sparse loadings from which factors or diffusion indexes can be formed. This allows us to build a more parsimonious factor model that is better suited for forecasting compared to the traditional principal components (PC) approach. We provide an asymptotic analysis of the estimator and illustrate its merits empirically in a forecasting experiment based on U.S. macroeconomic data. Overall we find that compared to PC we obtain improvements in forecasting accuracy and thus find it to be an important alternative to PC. Supplementary materials for this article are available online.  相似文献   
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147.
The most extensively studied influence on adolescent conduct problem behaviors is peers, and the literature points to genetics as one source of individual differences in peer influence. The purpose of this study was to test the hypothesis that an environmental sensitivity genetic index comprised of DRD4, 5‐HTTLPR, and GABRA2 variation would moderate the association between peer and adolescent conduct problems. Latent growth modeling was applied to PROSPER project longitudinal data from adolescents and their peers. Results showed the hypothesis was supported; adolescents with more copies of putative sensitivity alleles were more strongly influenced by their peers. The interaction form was consistent with differential susceptibility in follow‐up analyses. Strengths and weaknesses of genetic aggregates for sensitivity research are discussed.  相似文献   
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149.
Ethnic competition theory provides a powerful explanation for ethnic conflict, by demonstrating how variation in ethnic mobilization relates to intergroup struggles over scarce resources. However, the tendency to capture such relationships at the aggregate level, through macro-level proxies of intergroup competition, offers little insight into the processes through which ethnic grievances mobilize into contentious action. This article integrates insights from the social movements literature to address how competitive contexts crystallize into broader conflicts. Drawing on data from the civil rights-era Ku Klux Klan??perhaps the quintessential case of contentious ethnic organization in the United States??the analysis focuses on the ways in which meso-level arrangements mediate the relationship between overarching competitive contexts and ethnic conflict. Results of a paired comparative analysis of KKK mobilization in Greensboro and Charlotte demonstrate that social and spatial relations within each city shaped the contours of perceived competition and subsequent ethnic organization in ways that were not always predictable through observation of conventional proxies of competition.  相似文献   
150.
Social responsibility is an essential part of the responsible conduct of research that presents difficult ethical questions for scientists. Recognizing one’s social responsibilities as a scientist is an important first step toward exercising social responsibility, but it is only the beginning, since scientists may confront difficult value questions when deciding how to act responsibly. Ethical dilemmas related to socially responsible science fall into at least three basic categories: 1) dilemmas related to problem selection, 2) dilemmas related to publication and data sharing, and 3) dilemmas related to engaging society. In responding to these dilemmas, scientists must decide how to balance their social responsibilities against other professional commitments and how to avoid compromising their objectivity. In this article, we will examine the philosophical and ethical basis of social responsibility in science, discuss some of the ethical dilemmas related to exercising social responsibility, and make five recommendations to help scientists deal with these issues.  相似文献   
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