994 resultados para 7140-208
Resumo:
This paper presents a new multi-output DC/DC converter topology that has step-up and step-down conversion capabilities. In this topology, several output voltages can be generated which can be used in different applications such as multilevel converters with diode-clamped topology or power supplies with several voltage levels. Steady state and dynamic equations of the proposed multi-output converter have been developed, that can be used for steady state and transient analysis. Two control techniques have been proposed for this topology based on constant and dynamic hysteresis band height control to address different applications. Simulations have been performed for different operating modes and load conditions to verify the proposed topology and its control technique. Additionally, a laboratory prototype is designed and implemented to verify the simulation results.
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Purpose of the Study: A framework aids choice of interventions to manage wandering and prevent elopement in consideration of associated risks and mobility needs of wanderers. ---------- Design and Methods: A literature review, together with research results, published wandering tools, clinical reports, author clinical experience, and consensus-based judgments was used to build a decision-making framework. Results: Referencing a published definition of wandering and originating a clinical description of problematic wandering, authors introduce a framework comprising (1) wandering and related behaviors; (2) goals of wandering-specific care, (3) interpersonally, technologically, and policy-mediated wandering interventions, and (4) estimates of relative frequencies of wandering behaviors, magnitudes of elopement risk, and restrictiveness of strategies. ---------- Implications: Safeguarding wanderers from elopement risk is rendered person-centered and humane when goals of care guide intervention choice. Despite limitations, a reasoned, systematized approach to wandering management provides a basis for tailoring a specialized program of care. The need for framework refinement and related research is emphasized.
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European American (EA) women report greater body dissatisfaction and less dietary control than do African American (AA) women. This study investigated whether ethnic differences in dieting history contributed to differences in body dissatisfaction and dietary control, or to differential changes that may occur during weight loss and regain. Eighty-nine EA and AA women underwent dual-energy X-ray absorptiometry to measure body composition and completed questionnaires to assess body dissatisfaction and dietary control before, after, and one year following, a controlled weight-loss intervention. While EA women reported a more extensive dieting history than AA women, this difference did not contribute to ethnic differences in body dissatisfaction and perceived dietary control. During weight loss, body satisfaction improved more for AA women, and during weight regain, dietary self-efficacy worsened to a greater degree for EA women. Ethnic differences in dieting history did not contribute significantly to these differential changes. Although ethnic differences in body image and dietary control are evident prior to weight loss, and some change differentially by ethnic group during weight loss and regain, differences in dieting history do not contribute significantly to ethnic differences in body image and dietary control.
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High renewal and maintenance of multipotency of human adult stem cells (hSCs), are a prerequisite for experimental analysis as well as for potential clinical usages. The most widely used strategy for hSC culture and proliferation is using serum. However, serum is poorly defined and has a considerable degree of inter-batch variation, which makes it difficult for large-scale mesenchymal stem cells (MSCs) expansion in homogeneous culture conditions. Moreover, it is often observed that cells grown in serum-containing media spontaneously differentiate into unknown and/or undesired phenotypes. Another way of maintaining hSC development is using cytokines and/or tissue-specific growth factors; this is a very expensive approach and can lead to early unwanted differentiation. In order to circumvent these issues, we investigated the role of sphingosine-1-phosphate (S1P), in the growth and multipotency maintenance of human bone marrow and adipose tissue-derived MSCs. We show that S1P induces growth, and in combination with reduced serum, or with the growth factors FGF and platelet-derived growth factor-AB, S1P has an enhancing effect on growth. We also show that the MSCs cultured in S1P-supplemented media are able to maintain their differentiation potential for at least as long as that for cells grown in the usual serum-containing media. This is shown by the ability of cells grown in S1P-containing media to be able to undergo osteogenic as well as adipogenic differentiation. This is of interest, since S1P is a relatively inexpensive natural product, which can be obtained in homogeneous high-purity batches: this will minimize costs and potentially reduce the unwanted side effects observed with serum. Taken together, S1P is able to induce proliferation while maintaining the multipotency of different human stem cells, suggesting a potential for S1P in developing serum-free or serum-reduced defined medium for adult stem cell cultures.
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This paper looks at the decision-making process that determines the amount of effort frontline service employees will expend in delivering a service in a business-to-business context. Using theories in behavioural economics and interactional and social psychology, the paper develops and presents a model of employee decision-making. Managerial implications, which have the potential to enhance the marketing of business-to-business services and directions for future research in this area, are indicated.
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Purpose – The purpose of this paper is to examine the buyer awareness and acceptance of environmental and energy efficiency measures in the New Zealand residential property markets. This study aims to provide a greater understanding of consumer behaviour in the residential property market in relation to green housing issues ---------- Design/methodology/approach – The paper is based on an extensive survey of Christchurch real estate offices and was designed to gather data on the factors that were considered important by buyers in the residential property market. The survey was designed to allow these factors to be analysed on a socio-economic basis and to compare buyer behaviour based on property values. ---------- Findings – The results show that regardless of income levels, buyers still consider that the most important factor in the house purchase decision is the location of the property and price. Although the awareness of green housing issues and energy efficiency in housing is growing in the residential property market, it is only a major consideration for young and older buyers in the high income brackets and is only of some importance for all other buyer sectors of the residential property market. Many of the voluntary measures introduced by Governments to improve the energy efficiency of residential housing are still not considered important by buyers, indicating that a more mandatory approach may have to be undertaken to improve energy efficiency in the established housing market, as these measures are not valued by the buyer. ---------- Originality/value – The paper confirms the variations in real estate buyer behaviour across the full range of residential property markets and the acceptance and awareness of green housing issues and measures. These results would be applicable to most established and transparent residential property markets.
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The purpose of this paper is to present a framework to guide critical thinking through reflective journaling, and describe how a group of 20 Middle Eastern nurses used reflective journaling to enhance their practice. Journal documentation was used during clinical practicum to foster the development of critical thinking in order to assist nurses when analysing and evaluating their clinical experiences. The findings from this study demonstrated that nurses accepted the framework for journal documentation because it provided structure for reflection, speculation, synthesis and metacognition of events experienced during clinical practice. Journaling gave nurses the opportunity to transfer thoughts onto paper and write down subjective and objective data, and created dialogue between the nurse educators and nurses. They were engaged in productive and positive activity to enhance their nursing practice. Nurses also commented that writing helped to develop their confidence in writing English.
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This study examined pre-service teachers’ efficacy in relation to the utilisation of microteaching as an assessment tool for postgraduate education students in Australia. Three hundred and fifteen pre-service teachers completed the teacher efficacy survey and additional qualitative questions at Time 1 and 208 completed the survey and questions at Time 2. A principal components analysis conducted on the Time 1 survey data revealed teacher efficacy to be comprised of two components: ‘teacher efficacy in classroom management’ and ‘personal teacher efficacy’. Repeated measures ANOVAs conducted on the 208 participants who completed the survey at Time 1 and 2 revealed that efficacy on both components increased significantly over time, and that internet students had higher efficacy levels than internal students. The qualitative data revealed that pre-service teachers enter teaching in order to positively impact on children, yet are concerned about behaviour management in the classroom. In addition, this data highlighted the positive impact that microteaching had on their developing teacher identity.
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Purpose – The purpose of this paper is to develop a conceptual framework that can be used to identify capabilities needed in the management of infrastructure assets. Design/methodology/approach – This paper utilises a qualitative approach to analyse secondary data in order to develop a conceptual framework that identifies capabilities for strategic infrastructure asset management. Findings – In an external business environment that is undergoing rapid change, it is more appropriate to focus on factors internal to the organisation such as resources and capabilities as a basis to develop competitive advantage. However, there is currently very little understanding of the internal capabilities that are appropriate for infrastructure asset management. Therefore, a conceptual framework is needful to guide infrastructure organisations in the identification of capabilities. Research limitations/implications – This is a conceptual paper and future empirical research should be conducted to validate the propositions made in the paper. Practical implications – The paper clearly argues the need for infrastructure organisations to adopt a systematic approach to identifying the capabilities needed in the management of strategic infrastructure assets. The discussion on the impact of essential capabilities is useful in providing the impetus for managers who operate in a deregulated infrastructure business landscape to review their existing strategies. Originality/value – The paper provides a new perspective on how asset managers can create value for their organisations by investing in the relevant capabilities.
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Caulfield, Harold William; p.131 Cowan, Alexander; p.164 Cowley, Ebenezer; p.164 East Talgai Station; p.193 Eaves, S.H.; p.193-194 Edgar, J.S.; p.196 Everist, Selwyn; p.206 Experimental Farms and Gardens; pp.207-208 Government Houses - Queensland; pp.267-268
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Purpose: Although there is increasing evidence that the creative industries are essential to national economic growth as well as social and cultural well-being, creative graduates often find it difficult to become established professionally. This study investigates the value of career management competence and intrinsic career motivations (as elements of ‘protean career orientation’) in predicting positive graduate outcomes. ----- ----- Design/methodology: Self-report surveys were administered to 208 creative industries graduates from two Australian universities at two points in time: at course completion, and one year later. ----- ----- Findings: Individual career management competence and intrinsic work motivations, measured at course completion, were significant predictors of early career success, using both subjective and objective measures, measured one year later. ----- ----- Practical implications: This study suggests that an emphasis on student development beyond the traditional ‘key’ employability skills may well be worthwhile. The article also suggests a broad learning and teaching approach by which universities can encourage the development of student career identity, and thus engender student intrinsic career motivations and career self management skills and behaviours. ----- ----- Originality/value: This is one of the first studies to demonstrate empirically a link between a particular set of skills and graduate outcomes. In addition, it provides insights into the role of student career motivations in positive transitions to the world of work in the creative industries.