244 research outputs found

    Layers of powers: societies and institutions in Europe

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    Historians and social scientists have offered many and varied definitions of the term “community”. This chapter focuses on specific examples of face-to-face or local communities in order to test the possibilities and limits of the two major analytical approaches to communities: an anthropological approach which identifies ‘community’ as an organic entity, and a symbolic one which considers feelings of belonging and self-identification as constitutive aspects of a community. In this quest, close attention is paid to the question of the stabilization of community’s structures through legislation and institutions, a process that integrates such micro-societies into broader networks of power, and renders them visible to historians. In the first section we examine what we have called a “world of communities”, from periods when communities constituted the dominant element of social structure. Examining ancient Jewish and medieval Icelandic communities, and then early modern Irish and Scottish clans, we try to identify their basic characteristics and to reconstruct the way they related to the rest of the social structure. The second section analyzes the emergence of new loyalties and models of social membership from the 19th century onwards, emphasizing how the discourse on communities played a crucial role in the construction of these diverse patterns of identification and differentiation. Finally, we explore the permanence of the communitarian world supposedly replaced by nationalism and other major modern ideologies along with the new meanings and uses of communities in the 20th and 21st centuries. In sum, this broad overview provides a preliminary narrative of the changes in the structures of communities and their shifting position within wider patterns of social organizations while drawing attention to parallel transformations in theoretical reflection on communities

    A kinetic BGK edge-based scheme including vibrational and electronic energy modes for high-Mach flows

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    A first principles formulation for the calorically imperfect behavior of gases is here proposed within a Boltzmann-type discretisation of the Navier–Stokes equations. The formulation is intended to enhance the consistency of gas kinetic schemes (GKS) with the physics of supersonic and hypersonic regimes where vibrational and electronic energy modes are activated before any thermal nonequilibrium or chemical activity takes place. The so-called node-pair BGK scheme, an edge-based implementation of the GKS, is considered in the present work for the implementation of a thermodynamic model where the calorically imperfect behavior is obtained from a modification of the way the different moments of the particle distribution function are computed and eventually used to determine the fluxes of conserved quantities across the boundary of each control volume. The method is validated on a series of canonical test cases for supersonic and hypersonic flows

    Multiple removal of spent rocket upper stages with an ion beam shepherd

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    Among the many advantages of the recently proposed ion beam shepherd (IBS) debris removal technique is the capability to deal with multiple targets in a single mission. A preliminary analysis is here conducted in order to estimate the cost in terms of spacecraft mass and total mission time to remove multiple large-size upper stages of the Zenit family. Zenit-2 upper stages are clustered at 71 degrees inclination around 850 km altitude in low Earth orbit. It is found that a removal of two targets per year is feasible with a modest size spacecraft. The most favorable combinations of targets are outlined

    Chronic–Progressive Dopaminergic Deficiency Does Not Induce Midbrain Neurogenesis

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    Background: Consecutive adult neurogenesis is a well-known phenomenon in the ventricular–subventricular zone of the lateral wall of the lateral ventricles (V–SVZ) and has been controversially discussed in so-called “non-neurogenic” brain areas such as the periventricular regions (PVRs) of the aqueduct and the fourth ventricle. Dopamine is a known modulator of adult neural stem cell (aNSC) proliferation and dopaminergic neurogenesis in the olfactory bulb, though a possible interplay between local dopaminergic neurodegeneration and induction of aNSC proliferation in mid/hindbrain PVRs is currently enigmatic. Objective/Hypothesis: To analyze the influence of chronic–progressive dopaminergic neurodegeneration on both consecutive adult neurogenesis in the PVRs of the V–SVZ and mid/hindbrain aNSCs in two mechanistically different transgenic animal models of Parkinson´s disease (PD). Methods: We used Thy1-m[A30P]h α synuclein mice and Leu9′Ser hypersensitive α4* nAChR mice to assess the influence of midbrain dopaminergic neuronal loss on neurogenic activity in the PVRs of the V–SVZ, the aqueduct and the fourth ventricle. Results: In both animal models, overall proliferative activity in the V–SVZ was not altered, though the proportion of B2/activated B1 cells on all proliferating cells was reduced in the V–SVZ in Leu9′Ser hypersensitive α4* nAChR mice. Putative aNSCs in the mid/hindbrain PVRs are known to be quiescent in vivo in healthy controls, and dopaminergic deficiency did not induce proliferative activity in these regions in both disease models. Conclusions: Our data do not support an activation of endogenous aNSCs in mid/hindbrain PVRs after local dopaminergic neurodegeneration. Spontaneous endogenous regeneration of dopaminergic cell loss through resident aNSCs is therefore unlikely

    GeneMANIA Cytoscape plugin: fast gene function predictions on the desktop

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    Summary: The GeneMANIA Cytoscape plugin brings fast gene function prediction capabilities to the desktop. GeneMANIA identifies the most related genes to a query gene set using a guilt-by-association approach. The plugin uses over 800 networks from six organisms and each related gene is traceable to the source network used to make the prediction. Users may add their own interaction networks and expression profile data to complement or override the default data
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