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991.
Latent class analysis and multigroup mediation were used with 8,860 families in Chile to identify risk groups varying in socioeconomic status, family structure, and maternal depression, to determine whether profiles differed in children’s development of externalizing problems (EP) from 35 to 61 months, and maternal parenting that predicted EP. Four groups were identified: one no-risk profile and three risk profiles, impoverished and undereducated, depressed and impoverished, and father-absent and impoverished. All classes differed in EP. Maternal emotional support and harsh parenting were differentially associated with the development of EP across the three risk groups, relative to the low-risk group. Thus, specific constellations of adversities differentially predicted children’s EP and socialization processes mediating links between risk and EP. Implications are discussed.  相似文献   
992.
Research in Science Education - This paper addresses two methodological issues related to the assessment of teachers’ views of science. The first concerns the distinction between the...  相似文献   
993.
Science & Education - Issues associated with nature of science (NOS) have long been recognized as an essential component of scientific literacy. While consensus exists regarding the importance...  相似文献   
994.
995.
A bibliography is traditionally characterized by the judgments, bounded by explicit selection criteria, made by a single compiler. Because these criteria concern the attributes ascribed to a work and the needs of readers, bibliographic work is largely conceptual even across technological eras and domains. Yet, the development of networked information services, made possible by WWW infrastructure, has enabled very large numbers of people to discover, organize, and publish information, including bibliographies. Indeed, bibliographies, or at least bibliography-like artifacts, are a common genre of website, often published by people without specialized skills in information organization who follow non-rigorous selection procedures. Nevertheless, even if the items from these lists are poorly selected and described, this publishing activity is fundamentally important because it structures information locally, creating a patchy network of secondary access points. In turn, these access points enable information discovery, the formation and development of communities of interest, the estimation of document relevance by search engines, and so on. In sum, this activity, and the enabling technical infrastructure, invites bibliographies to take on new interactive possibilities. The aim of this article is to extend the traditional view of bibliography to encompass collaborative possibilities for wide, or narrow, participation in the shaping of bibliographies and the selection of items. This is done by examining the nature of bibliography on the Web, by proposing a conceptual model that opens bibliography to participatory practices, and by discussing a case study where a team sought to develop a bibliography of electronic resources. This examination reveals splendid opportunities for expanding the notion of bibliography with participatory policies while remaining true to its ancient roots.  相似文献   
996.
Supply and demand conditions that affect technological change in four functional areas of local government service delivery are described and analyzed. A consistent picture of small, fragmented markets, ‘lumpy’ demand, or uncertain markets is found, with demand shaped by a heterogeneous body of local procurement traditions and practices, low municipal technical capabilities, and risk-averse behavior by city officials and engineering consultants. Industries involved share a number of characteristics that bode poorly for industrial investment in innovation: low profit margins and uncertain financial futures. Firms that have the resources to invest in R&D do not tend to focus exclusively on municipal markets. The findings suggest that public policies directed toward improving the municipal market for innovative products by strengthening the cities' technological infrastructure will be more effective than policies directed toward the supply side such as increased R&D support.  相似文献   
997.
In 1982, the Small Business Innovation Development Act established the small business innovation research (SBIR) program. This program reserves a percentage of federal agencies’ extramural R&D budgets for research projects conducted by small businesses. When this Act was reauthorized in 1992, the selection criteria for funding dramatically increased the likelihood of funding for projects that promised to lead to commercial success. Using data from a survey of the SBIR program award recipients at NASA Langley Research Center, we address three questions about this change: (i) was there a shift to projects with more commercial potential? (ii) did these projects experience higher rates of commercial success? and (iii) was there a reduction in basic research accompanying the increased commercial success? Our analysis suggests, the answer to all three of these questions is ‘yes’.  相似文献   
998.
999.
The purpose of this paper is to examine whether the technical universities have been more successful in facilitating the spillover and commercialization of knowledge. We compare the impact of technical and general universities on the performance of knowledge-based firms. Based on a unique data set consisting of publicly held high technology firms, the empirical evidence suggests that, in fact, firm performance is not influenced by the type of university. Technical universities do not have a differential impact on firm performance from more general universities.  相似文献   
1000.
The relationship between institutional change and entrepreneurship is poorly understood. We build the theory in this area by tracing institutional change in the US electric power industry over a 40-year period. Our analysis shows that environmental jolts mobilize actors to reformulate institutions, resulting in increased entrepreneurial opportunity. When the institutional environment is stable, we find that incumbent organizational forms and embedded logics present formidable obstacles to entrepreneurial activity. Environmental jolts, however, catalyze search processes and motivate the evaluation of current institutional logics. Specifically, in the case of the electric power industry, environments of abundance and regulation resulted in homogeneity of organizational structures and strategies, and few entrepreneurial opportunities. Environments marked by scarcity and crisis, however, witnessed heavy scrutiny of existing institutional arrangements that eroded their taken-for-grantedness and symbolic value, resulting in opportunities for entrepreneurial action.  相似文献   
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