604 resultados para Unified growth theory


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It is known that boehmite (AlOOH) nanofibers formed in the presence of nonionic poly(ethylene oxide) (PEO) surfactant at 373 K. A novel approach is proposed in this study for the growth of the boehmite nanofibers: when fresh aluminum hydrate precipitate was added at regular interval to initial mixture of boehmite and PEO surfactant at 373 K, the nanofibers grow from 40 to 50 nm long to over 100 nm. It is believed that the surfactant micelles play an important role in the nanofiber growth: directing the assembly of aluminum hydrate particles through hydrogen bonding with the hydroxyls on the surface of aluminum hydrate particles. Meanwhile a gradual improvement in the crystallinity of the fibers during growth is observed and attributed to the Ostwald ripening process. This approach allows us to precisely control the size and morphology of boehmite nanofibers using soft chemical methods and could be useful for low temperature, aqueous syntheses of other oxide nanomaterials with tailorable structural specificity such as size, dimension and morphology.

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This study develops a life-cycle model where investors make investment decisions in a realistic environment. Model results show that personal illiquid projects (housing and children), fixed costs (once-off/per-period participation costs plus variable/fixed transaction costs) and endogenous risky human capital (with permanent, transitory and disastrous shocks) together are able to address both the non-participation puzzle and the age-effects puzzle. Empirical implications of the model are examined using Heckman’s two-step method with the latest five Surveys of Consumer Finance (SCF). Regression results show that liquidity, informational cost and human capital are indeed the major determinants of participation and asset allocation decisions at different stages of an investor’s life.

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The issue of ‘rigour vs. relevance’ in IS research has generated an intense, heated debate for over a decade. It is possible to identify, however, only a limited number of contributions on how to increase the relevance of IS research without compromising its rigour. Based on a lifecycle view of IS research, we propose the notion of ‘reality checks’ in order to review IS research outcomes in the light of actual industry demands. We assume that five barriers impact the efficient transfer of IS research outcomes; they are lack of awareness, lack of understandability, lack of relevance, lack of timeliness, and lack of applicability. In seeking to understand the effect of these barriers on the transfer of mature IS research into practice, we used focus groups. We chose DeLone and McLean’s IS success model as our stimulus because it is one of the more widely researched areas of IS.

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The difficulty of communicating during organizational change has intensified with the prevalence of continuously changing organizations (Buchanan, Claydon & Doyle, 1999). The difficulty faced by managers is compounded by the lack of studies examining organizational communication within a context of organizational change (Eisenberg, Andrews, Murphy, & Laine-Timmerman, 1999; Lewis & Seibold, 1996). Not surprisingly then, is there a paucity of organizational change theory to guide further research and practitioners. This paper addresses the lack of organizational change communication research and contributes to theoretical development of communication during organizational change. A model of change communication during continuous change is presented from the analysis of two longitudinal empirical studies. Central constructs of the model are the monologic change communication, the dialogic change communication and the background talk of change. Further Van de Ven and Poole's (1995) Process Theories of Change are extended to consider the sequencing of the three constructs. The findings suggest that the sequencing of the dominant change communication approaches is informed by an alignment of individual communication competences and organizational change communication expectations.