923 research outputs found

    Membrane properties of ameboid microglial cells in the corpus callosum slice from early postnatal mice

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    Microglial cells in culture are distinct from neurons, macroglial cells, and macrophages of tissues other than brain with respect to their membrane current pattern. To assess these cells in the intact tissue, we have applied the patch-clamp technique to study membrane currents in microglial cells from acute, whole brain slices of 6-9-d-old mice in an area of microglial cell invasion, the cingulum. As strategies to identify microglial cells prior to or after recording, we used binding and incorporation of Dil-acetylated low-density lipoproteins, binding of fluorescein isothiocyanate-coupled IgG via microglial Fc-receptors, and ultrastructural characterization. As observed previously for cultured microglial cells, depolarizing voltage steps activate only minute if any membrane currents, while hyperpolarizing voltage steps induced large inward currents. These currents exhibited properties of the inwardly rectifying K+ channel in that the reversal potential depended on the transmembrane K+ gradient, inactivation time constants decreased with hyperpolarization, and the current was blocked by tetraethylammonium (50 mM). This study represents the first attempt to assess microglial cells in situ using electrophysiological methods. It opens the possibility to address questions related to the function of microglial cells in the intact CNS

    Institutionalization of REDD+ MRV in Indonesia, Peru, and Tanzania : progress and implications

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    Reducing emissions from deforestation and forest degradation in developing countries (REDD+) has opened up a new global discussion on forest monitoring and carbon accounting in developing countries. We analyze and compare the extent to which the concept of measurement, reporting, and verification (MRV) for REDD+ has become institutionalized in terms of new policy discourses, actors, resources, and rules in Indonesia, Peru, and Tanzania. To do so, we draw on discursive institutionalism and the policy arrangement approach. A qualitative scale that distinguishes between "shallow" institutionalization on the one end, and "deep" institutionalization on the other, is developed to structure the analysis and comparison. Results show that in all countries MRV has become institutionalized in new or revised aims, scope, and strategies for forest monitoring, and development of new agencies and mobilization of new actors and resources. New legislations to anchor forest monitoring in law and procedures to institutionalize the roles of the various agencies are being developed. Nevertheless, the extent to which MRV has been institutionalized varies across countries, with Indonesia experiencing "deep" institutionalization, Peru "shallow-intermediate" institutionalization, and Tanzania "intermediate-deep" institutionalization. We explore possible reasons for and consequences of differences in extent of institutionalization of MRV across countries.Peer reviewe

    Climate policy integration in the land use sector: Mitigation, adaptation and sustainable development linkages

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    This article re-conceptualizes Climate Policy Integration (CPI) in the land use sector to highlight the need to assess the level of integration of mitigation and adaptation objectives and policies to minimize trade-offs and to exploit synergies. It suggests that effective CPI in the land use sector requires i) internal climate policy coherence between mitigation and adaptation objectives and policies; ii) external climate policy coherence between climate change and development objectives; iii) vertical policy integration to mainstream climate change into sectoral policies and; iv) horizontal policy integration by overarching governance structures for cross-sectoral coordination. This framework is used to examine CPI in the land use sector of Indonesia. The findings indicate that adaptation actors and policies are the main advocates of internal policy coherence. External policy coherence between mitigation and development planning is called for, but remains to be operationalized. Bureaucratic politics has in turn undermined vertical and horizontal policy integration. Under these circumstances it is unlikely that the Indonesian bureaucracy can deliver strong coordinated action addressing climate change in the land use sector, unless sectoral ministries internalize a strong mandate on internal and external climate policy coherence and find ways to coordinate policy action effectively

    Creating Entrepreneurial Opportunities as a Means to Maintain Entrepreneurial Talent in Corporations

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    This paper considers how to retain the right talent to support corporate entrepreneurial interests such as internal corporate ventures by taking a new look at why individuals leave corporations and become entrepreneurs. We sought to first examine why entrepreneurs leave. The job satisfaction model tests the popular belief that individuals quit due to dissatisfaction. This is compared to the person-environment (P-E) fit model that theorizes individuals are pushed away and pulled into environments that present a better fit. In all, 715 nascent entrepreneurs were compared with 399 employees by regression and graphic analyses. Contrary to conventional wisdom, we found that for these entrepreneurs, dissatisfaction does not precede the entrepreneurial exodus from established companies. Rather, the perceptions of their new venture’s competitive certainty and financial certainty pull them into new business ventures. Implications and suggestions for the managers are discussed

    Thermal expansion in small metal clusters and its impact on the electric polarizability

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    The thermal expansion coefficients of NaN\mathrm{Na}_{N} clusters with 8N408 \le N \le 40 and Al7\mathrm{Al}_{7}, Al13\mathrm{Al}_{13}^- and Al14\mathrm{Al}_{14}^- are obtained from {\it ab initio} Born-Oppenheimer LDA molecular dynamics. Thermal expansion of small metal clusters is considerably larger than that in the bulk and size-dependent. We demonstrate that the average static electric dipole polarizability of Na clusters depends linearly on the mean interatomic distance and only to a minor extent on the detailed ionic configuration when the overall shape of the electron density is enforced by electronic shell effects. The polarizability is thus a sensitive indicator for thermal expansion. We show that taking this effect into account brings theoretical and experimental polarizabilities into quantitative agreement.Comment: 4 pages, 2 figures, one table. Accepted for publication in Physical Review Letters. References 10 and 23 update

    Presynaptic α2δ subunits are key organizers of glutamatergic synapses

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    In nerve cells the genes encoding for α2δ subunits of voltage-gated calcium channels have been linked to synaptic functions and neurological disease. Here we show that α2δ subunits are essential for the formation and organization of glutamatergic synapses. Using a cellular α2δ subunit triple-knockout/knockdown model, we demonstrate a failure in presynaptic differentiation evidenced by defective presynaptic calcium channel clustering and calcium influx, smaller presynaptic active zones, and a strongly reduced accumulation of presynaptic vesicle-associated proteins (synapsin and vGLUT). The presynaptic defect is associated with the downscaling of postsynaptic AMPA receptors and the postsynaptic density. The role of α2δ isoforms as synaptic organizers is highly redundant, as each individual α2δ isoform can rescue presynaptic calcium channel trafficking and expression of synaptic proteins. Moreover, α2δ-2 and α2δ-3 with mutated metal ion-dependent adhesion sites can fully rescue presynaptic synapsin expression but only partially calcium channel trafficking, suggesting that the regulatory role of α2δ subunits is independent from its role as a calcium channel subunit. Our findings influence the current view on excitatory synapse formation. First, our study suggests that postsynaptic differentiation is secondary to presynaptic differentiation. Second, the dependence of presynaptic differentiation on α2δ implicates α2δ subunits as potential nucleation points for the organization of synapses. Finally, our results suggest that α2δ subunits act as transsynaptic organizers of glutamatergic synapses, thereby aligning the synaptic active zone with the postsynaptic density

    How to Educate Entrepreneurs?

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    Entrepreneurship education has two purposes: To improve students’ entrepreneurial skills and to provide impetus to those suited to entrepreneurship while discouraging the rest. While entrepreneurship education helps students to make a vocational decision its effects may conflict for those not suited to entrepreneurship. This study shows that vocational and the skill formation effects of entrepreneurship education can be identified empirically by drawing on the Theory of Planned Behavior. This is embedded in a structural equation model which we estimate and test using a robust 2SLS estimator. We find that the attitudinal factors posited by the Theory of Planned Behavior are positively correlated with students’ entrepreneurial intentions. While conflicting effects of vocational and skill directed course content are observed in some individuals, overall these types of content are complements. This finding contradicts previous results in the literature. We reconcile the conflicting findings and discuss implications for the design of entrepreneurship courses

    Legitimacy in REDD+ governance in Indonesia

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    This paper addresses the question of legitimacy in REDD+ governance in Indonesia. It develops a legitimacy framework that builds on elements of Scharpf (J Eur Pub Policy 4(1):18–36, 1997) input and output legitimacy concept and the political economy lens described by Brockhaus and Angelsen (Analysing REDD+: Challenges and choices, CIFOR, Bogor, 2012). Using data collected through key informant interviews and focus groups, we identify and explore stakeholder perceptions of legitimacy. The analysis reveals a complex interplay between input and output legitimacy, finding that state, non-state and hybrid actors perceive output legitimacy (i.e. project outcomes) as highly dependent on the level of input legitimacy achieved during the governance process. Non-state actors perceive proxies for input legitimacy, such as participation and inclusion of local people, as goals in themselves. In the main, they perceive inclusion to be integral to the empowerment of local people. They perceive output legitimacy as less important because of the intangibility of REDD+ outcomes at this stage in the process. The findings also highlight the challenges associated with measuring the legitimacy of REDD+ governance in Indonesia

    Forest-Poverty Dynamics: Current State of Knowledge

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    This chapter reports on evidence about the role of forests and trees in alleviating poverty and supporting wider human well-being. It considers how, whether, where, when and for whom forests and trees are important in forest-poverty dynamics. We organise the evidence according to four possible relationships between forest products and ecosystem services and poverty: 1) helping households move out of poverty; 2) supporting well-being through subsistence, food security and cultural and spiritual values; 3) mitigating risks; and 4) decreasing well-being by generating negative externalities that could significantly contribute to trapping or moving households into poverty. The evidence shows that these relationships are strongly context-dependent, varying with geography and social, economic and political contexts. However, across contexts, we most commonly observe that forest and tree products and services help the poor to secure and stabilise their livelihoods, rather than either helping them exit poverty or driving them into poverty.Peer reviewe
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