227 research outputs found

    Extended moment formation and magnetic ordering in the trigonal chain compound Ca3Co2O6

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    The results of electronic structure calculations for the one-dimensional magnetic chain compound Ca3Co2O6 are presented. The calculations are based on density functional theory and the local density approximation and used the augmented spherical wave (ASW) method. Our results allow for deeper understanding of recent experimental findings. In particular, alternation of Co 3d low- and high-spin states along the characteristic chains is related to differences in the oxygen coordination at the inequivalent cobalt sites. Strong hybridization of the d states with the O 2p states lays ground for polarization of the latter and the formation of extended localized magnetic moments centered at the high-spin sites. In contrast, strong metal-metal overlap along the chains gives rise to intrachain ferromagnetic exchange coupling of the extended moments via the d_{3z^2-r^2} orbitals of the low-spin cobalt atoms.Comment: 10 pages, 4 figures more information at http://www.physik.uni-augsburg.de/~eyert

    Phosphatidylinositol-4,5 Bisphosphate Produced by PIP5K(gamma) Regulates Gelsolin, Actin Assembly, and Adhesion Strength of N-Cadherin Junctions

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    Phosphoinositides regulate several actin-binding proteins but their role at intercellular adhesions has not been defined. We found that phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) was generated at sites of N-cadherin–mediated intercellular adhesion and was a critical regulator of intercellular adhesion strength. Immunostaining for PI(4,5)P2 or transfection with GFP-PH-PLCή showed that PI(4,5)P2 was enriched at sites of N-cadherin adhesions and this enrichment required activated Rac1. Isoform-specific immunostaining for type I phosphatidylinositol 4-phosphate 5 kinase (PIP5KI) showed that PIP5KIγ was spatially associated with N-cadherin–Fc beads. Association of PIP5KIγ with N-cadherin adhesions was in part dependent on the activation of RhoA. Transfection with catalytically inactive PIP5KIγ blocked the enrichment of PI(4,5)P2 around beads. Catalytically inactive PIP5KIγ or a cell-permeant peptide that mimics and competes for the PI(4,5)P2-binding region of the actin-binding protein gelsolin inhibited incorporation of actin monomers in response to N-cadherin ligation and reduced intercellular adhesion strength by more than twofold. Gelsolin null fibroblasts transfected with a gelsolin severing mutant containing an intact PI(4,5)P2 binding region, demonstrated intercellular adhesion strength similar to wild-type transfected controls. We conclude that PIP5KIγ-mediated generation of PI(4,5)P2 at sites of N-cadherin contacts regulates intercellular adhesion strength, an effect due in part to PI(4,5)P2-mediated regulation of gelsolin

    Magnetic ordering in trigonal chain compounds

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    We present electronic structure calculations for the one-dimensional magnetic chain compounds Ca_3CoRhO_6 and Ca_3FeRhO_6. The calculations are based on density functional theory and the local density approximation. We use the augmented spherical wave (ASW) method. The observed alternation of low- and high-spin states along the Co-Rh and Fe-Rh chains is related to differences in the oxygen coordination of the transition metal sites. Due to strong hybridization the O 2p states are polarized, giving rise to extended localized magnetic moments centered at the high-spin sites. Strong metal-metal overlap along the chains leads to a substantial contribution of the low-spin Rh 4d_{3z^2-r^2} orbitals to the exchange coupling of the extended moments. Interestingly, this mechanism holds for both compounds, even though the coupling is ferromagnetic for the cobalt and antiferromagnetic for the iron compound. However, our results allow to understand the different types of coupling from the filling dependence of the electronic properties.Comment: 8 pages, 3 figures, more information at http://www.physik.uni-augsburg.de/~eyert

    Looking ‘beyond the factory gates’:towards more pluralist and radical approaches to intra-organizational trust research

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    The aim of this paper is to suggest new avenues for trust research by critiquing the extant literature on this topic. We analyze the most influential research on intra-organizational trust from the perspective of a classic industrial sociology framework from the 1970s – Alan Fox’s work on frames of reference and trust dynamics. Our analysis of intra-organizational trust studies leads us to three conclusions. Firstly, the large majority of intra-organizational trust research has strong unitarist underpinnings, which support a managerial agenda that is potentially detrimental to employees’ and (indeed managers’) long-term interests. Secondly, most of this research fails to explain how trust in organizations is embedded in societal and field level institutions, hence it would benefit from looking ‘beyond the factory gates’ for a more complete understanding of trust dynamics in organizations. In this connection, we argue that Fox’s pluralist and radical perspectives, which are under-represented in intra-organizational trust research, could provide new lines of inquiry by locating internal trust relations in a wider institutional context. Thirdly, Fox’s explanation of how low and high trust dynamics in organizations are embedded in wider society may help address the concerns about under-socialized, endogenous explanations and open the way for structure-agency analyses of building, maintaining and repairing intra-organizational trust

    Is organizational justice climate at the workplace associated with individual-level quality of care and organizational affective commitment?:A multi-level, cross-sectional study on dentistry in Sweden

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    Purpose The aim of this study is to investigate whether organizational justice climate at the workplace level is associated with individual staff members’ perceptions of carequality and affective commitment to the workplace.Methods The study adopts a cross-sectional multi-level design. Data were collected using an electronic survey and a response rate of 75% was obtained. Organizational justice climate and affective commitment to the workplace were measured by items from Copenhagen Psychosocial Questionnaire and quality of care by three self-developed items. Non-managerial staff working at dental clinics with at least five respondents (n = 900 from 68 units) was included in analyses. A set of Level-2 random intercept models were built to predict individual-level organizational affective commitment and perceived quality of care from unit-level organizational justice climate, controlling for potential confoundingby group size, gender, age, and occupation.Results The results of the empty model showed substantial between-unit variation for both affective commitment (ICC-1 = 0.17) and quality of care (ICC-1 = 0.12). The overall results showed that the shared perception of organizational justice climate at the clinical unit level was significantly associated with perceived quality of care and affective commitment to the organization (p < 0.001).Conclusions Organizational justice climate at work unit level explained all variation in affective commitment among dental clinics and was associated with both the individualstaff members’ affective commitment and perceived quality of care. These findings suggest a potential for that addressing organizational justice climate may be a way to promote quality of care and enhancing affective commitment. However, longitudinal studies are needed to support causality in the examined relationships. Intervention research is also recommended to probe the effectiveness of actions increasingunit-level organizational justice climate and test their impact on quality of care and affective commitment

    The impact on nurses and nurse managers of introducing PEPFAR clinical services in urban government clinics in Uganda

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    BACKGROUND: Improving provider performance is central to strengthening health services in developing countries. Because of critical shortages of physicians, many clinics in sub-Saharan Africa are led by nurses. In addition to clinical skills, nurse managers need practical managerial skills and adequate resources to ensure procurement of essential supplies, quality assurance implementation, and productive work environment. Giving nurses more autonomy in their work empowers them in the workplace and has shown to create positive influence on work attitudes and behaviors. The Infectious Disease Institute, an affiliate of Makerere University College of Health Science, in an effort to expand the needed HIV services in the Ugandan capital, established a community-university partnership with the Ministry of Health to implement an innovative model to build capacity in HIV service delivery. This paper evaluates the impact on the nurses from this innovative program to provide more health care in six nurse managed Kampala City Council (KCC) Clinics. METHODS: A mixed method approach was used. The descriptive study collected key informant interviews from the six nurse managers, and administered a questionnaire to 20 staff nurses between September and December 2009. Key themes were manually identified from the interviews, and the questionnaire data were analyzed using SPSS. RESULTS: Introducing new HIV services into six KCC clinics was positive for the nurses. They identified the project as successful because of perceived improved environment, increase in useful in-service training, new competence to manage patients and staff, improved physical infrastructure, provision of more direct patient care, motivation to improve the clinic because the project acted on their suggestions, and involvement in role expansion. All of these helped empower the nurses, improving quality of care and increasing job satisfaction. CONCLUSIONS: This community-university HIV innovative model was successful from the point of view of the nurses and nurse managers. This model shows promise in increasing effective, quality health service; HIV and other programs can build capacity and empower nurses and nurse managers to directly implement such services. It also demonstrates how MakCHS can be instrumental through partnerships in designing and testing effective strategies, building human health resources and improving Ugandan health outcomes
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