863 resultados para Demster-Schafer theory of evidence
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Motivated by a novel stylized fact { countries with isolated capital cities display worse quality of governance { we provide a framework of endogenous institutional choice based on the idea that elites are constrained by the threat of rebellion, and that this threat is rendered less e ective by distance from the seat of political power. In established democracies, the threat of insurgencies is not a binding constraint, and the model predicts no correlation between isolated capitals and misgovernance. In contrast, a correlation emerges in equilibrium in the case of autocracies. Causality runs both ways: broader power sharing (associated with better governance) means that any rents have to be shared more broadly, hence the elite has less of an incentive to protect its position by isolating the capital city; conversely, a more isolated capital city allows the elite to appropriate a larger share of output, so the costs of better governance for the elite, in terms of rents that would have to be shared, are larger. We show evidence that this pattern holds true robustly in the data. We also show that isolated capitals are associated with less power sharing, a larger income premium enjoyed by capital city inhabitants, and lower levels of military spending by ruling elites, as predicted by the theory.
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This paper presents a simple theory of the provision of incentives in firms in which the principal optimally chooses both compensation contracts and the composition of the work force. Assuming that individuals display group loyalty, a less diverse (more homogeneous) work force will be more cooperative. Simple comparative statics provide some testable implications relating risk, diversity and incentive pay. I also analyze the case in which workers’ characteristics cannot be readily observed ex ante. The theory then predicts that firms are more likely to prevent workers from interacting with each other when workers are expected to have similar characteristics. This shows a surprising effect of diversity in the workplace: more diverse firms will promote more interactions between workers of different types, i.e. they will be less segregated. I test the main predictions of the model using a cross-sectional sample of corporate boards. I use the proportion of women on boards as a measure of diversity. There are three main empirical findings: (1) a significant negative correlation between firm risk and diversity, (2) a significant positive relationship between performance-based compensation and diversity and (3) a significant positive correlation between the number of board meetings (a measure of interactions among directors) and diversity. The evidence is broadly consistent with the implications of the theory.
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We extend the static portfolio choice problem with a small background risk to the case of small partially correlated background risks. We show that respecting the theories under which risk substitution appears, except for the independence of background risk, it is perfectly rational for the individual to increase his optimal exposure to portfolio risk when risks are partially negatively correlated. Then, we test empirically the hypothesis of risk substitutability using INSEE data on French households. We find that households respond by increasing their stockholdings in response to the increase in future earnings uncertainty. This conclusion is in contradiction with results obtained in other countries. So, in light of these results, our model provides an explanation to account for the lack of empirical consensus on cross-country tests of risk substitution theory that encompasses and criticises all of them.
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Includes bibliography
Development of meta-representations: Procedural metacognition and the relationship to Theory of Mind
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In several studies it was shown that metacognitive ability is crucial for children and their success in school. Much less is known about the emergence of that ability and its relationship to other meta-representations like Theory of Mind competencies. In the past years, a growing literature has suggested that metacognition and Theory of Mind could theoretically be assumed to belong to the same developmental concept. Since then only a few studies showed empirically evidence that metacognition and Theory of Mind are related. But these studies focused on declarative metacognitive knowledge rather than on procedural metacognitive monitoring like in the present study: N = 159 children were first tested shortly before making the transition to school (aged between 5 1/2 and 7 1/2 years) and one year later at the end of their first grade. Analyses suggest that there is in fact a significant relation between early metacognitive monitoring skills (procedural metacognition) and later Theory of Mind competencies. Notably, language seems to play a crucial role in this relationship. Thus our results bring new insights in the research field of the development of meta-representation and support the view that metacognition and Theory of Mind are indeed interrelated, but the precise mechanisms yet remain unclear.
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Knowles, Persico, and Todd (2001) develop a model of police search and offender behavior. Their model implies that if police are unprejudiced the rate of guilt should not vary across groups. Using data from Interstate 95 in Maryland, they find equal guilt rates for African-Americans and whites and conclude that the data is not consistent with racial prejudice against African-Americans. This paper generalizes the model of Knowles, Persico, and Todd by accounting for the fact that potential offenders are frequently not observed by the police and by including two different levels of offense severity. The paper shows that for African-American males the data is consistent with prejudice against African-American males, no prejudice, and reverse discrimination depending on the form of equilibria that exists in the economy. Additional analyses based on stratification by type of vehicle and time of day were conducted, but did not shed any light on the form of equilibria that best represents the situation in Maryland during the sample period.
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The ability of public health practitioners (PHPs) to work efficiently and effectively is negatively impacted by their lack of knowledge of the broad range of evidence-based practice information resources and tools that can be utilized to guide them in their development of health policies and programs. This project, a three-hour continuing education hands-on workshop with supporting resources, was designed to increase knowledge and skills of these resources. The workshop was presented as a pre-conference continuing education program for the Texas Public Health Association (TPHA) 2008 Annual Conference. Topics included: identification of evidence-based practice resources to aid in the development of policies and programs; identification of sources of publicly available data; utilization of data for community assessments; and accessing and searching the literature through a collection of databases available to all citizens of Texas. Supplemental resources included a blog that served as a gateway to the resources explored during the presentation, a community assessment workbook that incorporates both Healthy People 2010 objectives and links to reliable sources of data, and handouts providing additional instruction on the use of the resources covered during the workshop.^ Before- and after-workshop surveys based on Kirkpatrick's 4-level model of evaluation and the Theory of Planned Behavior were administered. Of the questions related to the trainer, the workshop, and the usefulness of the workshop, participants gave "Good" to "Excellent" responses to all one question. Confidence levels overall increased a statistically significant amount; measurements of attitude, social norms, and control showed no significant differences before and after the workshop. Lastly, participants indicated they were likely to use resources shown during the workshop within a one to three month time period on average. ^ The workshop and creation of supplemental resources served as a pilot for a funded project that will be continued with the development and delivery of four 4-week long webinar-based training sessions to be completed by December 2008. ^
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The general research question for this dissertation was: do the data on adolescent sexual experiences and sexual initiation support the explicit or implicit adolescent sexuality theories informing the sexual health interventions currently designed for youth? To respond to this inquiry, three different studies were conducted. The first study included a conceptual and historical analysis of the notion of adolescence introduced by Stanley Hall, the development of an alternative model based on a positive view of adolescent sexuality, and the rationale for introducing to adolescent sexual health prevention programs the new definitions of sexual health and the social determinants of health approach. The second one was a quantitative study aimed at surveying not only adolescents' risky sexual behaviors but also sexual experiences associated with desire/pleasure which have been systematically neglected when investigating the sexual and reproductive health of the youth. This study was conducted with a representative sample of the adolescents attending public high schools in the State of Caldas in the Republic of Colombia. The third study was a qualitative analysis of 22 interviews conducted with male and female U.S. Latino adolescents on the reasons for having had or having not had vaginal sex. The more relevant results were: most current adolescent sexual health prevention programs are still framed in a negative approach to adolescent sexuality developed a century ago by Stanley Hall and Sigmund Freud which do not accept the adolescent sexual experience and propose its sublimation. In contrast, the Colombian study indicates that, although there are gender differences, adolescence is for males and females a normal period of sexual initiation not limited to coital activity, in which sexual desire/pleasure is strongly associated with sexual behavior. By the same token, the study about the reasons for having had or not had initiated heterosexual intercourse indicated that curiosity, sexual desire/pleasure, and love are basic motivations for deciding to have vaginal sexual intercourse for the first time and that during adolescence, young women and men reach the cognitive development necessary for taking conscious decisions about their sexual acts. The findings underline the importance of asking pertinent questions about desire/pleasure when studying adolescent sexuality and adopting an evidence-based approach to sexual health interventions.^
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If payment of goods is easily default, economic transaction may deeply suffer from the risk. This risky environment formed a mechanism that governs how economic transaction is realized, subsequently how trade credit is given. This paper distinguished ex ante bargaining and ex post enforcement, then modeled that bargaining power reduces trade credit ex ante, and ex post enforcement power and cash in hand of buyer can enhances both trade amount and trade credit in a presence of default risk. We modeled this relationship in order to organize findings from previous literature and from our original micro data on detailed transaction in China to consistently understand the mechanism governing trade credit. Then empirically tested a structure from the theoretical prediction with data. Results show that ex post enforcement power of seller mainly determines size of trade credit and trade amount, cash in hand of buyer can substitute with enforcement power; Bargaining power of seller is exercised to reduces trade credit and trade amount for avoiding default risk, but it simultaneously improves enforcement power as well. We found that ex post enforcement power consists of (ex ante) bargaining power on between two parties and intervention from the third party. However, its magnitude is far smaller than the direct impact to reduce trade credit and trade amount.
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This paper proposes a model that accounts for “export platform” FDI – a form of FDI that is common in the data but rarely discussed in the theoretical literature. Unlike the previous literature, this paper’s theory nests all the typical modes of supply, including exports, horizontal and vertical FDI, horizontal and vertical export platform FDI. The theory yields the testable hypothesis that a decrease in either inter-regional or intra-regional trade costs induces firms to choose export platform FDI. The empirical analysis provides descriptive statistics which point to large proportions of third country exports of US FDI, and an econometric analysis, whose results are in line with the model’s predictions. The last section suggests policy implications for nations seeking to attract FDI.
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Fourier transform-infrared/statistics models demonstrate that the malignant transformation of morphologically normal human ovarian and breast tissues involves the creation of a high degree of structural modification (disorder) in DNA, before restoration of order in distant metastases. Order–disorder transitions were revealed by methods including principal components analysis of infrared spectra in which DNA samples were represented by points in two-dimensional space. Differences between the geometric sizes of clusters of points and between their locations revealed the magnitude of the order–disorder transitions. Infrared spectra provided evidence for the types of structural changes involved. Normal ovarian DNAs formed a tight cluster comparable to that of normal human blood leukocytes. The DNAs of ovarian primary carcinomas, including those that had given rise to metastases, had a high degree of disorder, whereas the DNAs of distant metastases from ovarian carcinomas were relatively ordered. However, the spectra of the metastases were more diverse than those of normal ovarian DNAs in regions assigned to base vibrations, implying increased genetic changes. DNAs of normal female breasts were substantially disordered (e.g., compared with the human blood leukocytes) as were those of the primary carcinomas, whether or not they had metastasized. The DNAs of distant breast cancer metastases were relatively ordered. These findings evoke a unified theory of carcinogenesis in which the creation of disorder in the DNA structure is an obligatory process followed by the selection of ordered, mutated DNA forms that ultimately give rise to metastases.
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An evolutionary framework for viewing the formation, the stability, the organizational structure, and the social dynamics of biological families is developed. This framework is based upon three conceptual pillars: ecological constraints theory, inclusive fitness theory, and reproductive skew theory. I offer a set of 15 predictions pertaining to living within family groups. The logic of each is discussed, and empirical evidence from family-living vertebrates is summarized. I argue that knowledge of four basic parameters, (i) genetic relatedness, (ii) social dominance, (iii) the benefits of group living, and (iv) the probable success of independent reproduction, can explain many aspects of family life in birds and mammals. I suggest that this evolutionary perspective will provide insights into understanding human family systems as well.
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Mode of access: Internet.
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Half-title: Princeton university. The Louis Clark Vanuxem foundation lectures for 1915-1916.
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Printer's statement on verso of title page: London: Harrison and Co., Printers, St. Martin's Lane.