2,676 research outputs found

    Post-Foucauldian governmentality: what does it offer critical social policy analysis?

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    This article considers the theoretical perspective of post-Foucauldian governmentality, especially the insights and challenges it poses for applied researchers within the critical social policy tradition. The article firstly examines the analytical strengths of this approach to understanding power and rule in contemporary society, before moving on to consider its limitations for social policy. It concludes by arguing that these insights can be retained, and some of the weaknesses overcome, by adopting a ‘realist governmentality’ approach (Stenson 2005, 2008). This advocates combining traditional discursive analysis with more ethnographic methods in order to render visible the concrete activity of governing, and unravel the messiness, complexity and unintended consequences involved in the struggles around subjectivity

    An upper limit on the X-ray luminosity of the black hole - microlens OGLE-1999-BUL-32

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    We present an upper limit on the 3--20 keV X-ray flux from the black hole - microlens OGLE-1999-BUL-32, based on RXTE/PCA scans over the Galactic Center region in 1999-2000. It is shown that the X-ray luminosity of the black hole did not exceed L(3-20 keV)<3e33(d/1kpc)^2 ergs/s (where d is the distance to the black hole). Near the maximum of the background star amplification by the microlens (July 6, 1999), the upper limit on the X-ray flux corresponds to an X-ray luminosity L(3-20 keV)<7e33(d/1kpc)^2 ergs/s.Comment: 4 pages, 3 figures. Accepted for publication in Astronomy Letter

    CXCL-8/IL8 Produced by Diffuse Large B-cell Lymphomas Recruits Neutrophils Expressing a Proliferation-Inducing Ligand APRIL.

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    Tumor-infiltrating neutrophils have been implicated in malignant development and progression, but mechanisms are ill defined. Neutrophils produce a proliferation-inducing ligand APRIL/TNFSF13, a factor that promotes development of tumors from diverse origins, including diffuse large B-cell lymphoma (DLBCL). High APRIL expression in DLBCL correlates with reduced patient survival, but the pathway(s) dictating APRIL expression are not known. Here, we show that all blood neutrophils constitutively secrete APRIL, and inflammation-associated stimuli, such as TNF, further upregulate APRIL. In a significant fraction of DLBCL patients, tumor cells constitutively produced the ELC-CXC chemokine CXCL-8 (IL8), enabling them to recruit APRIL-producing blood neutrophils. CXCL-8 production in DLBCL was unrelated to the cell of origin, as APRIL-producing neutrophils infiltrated CXCL-8(+) DLBCL from both germinal center (GC) and non-GC subtypes. Rather, CXCL-8 production implied events affecting DNA methylation and acetylation. Overall, our results showed that chemokine-mediated recruitment of neutrophils secreting the tumor-promoting factor APRIL mediates DLBCL progression. Cancer Res; 77(5); 1097-107. ©2016 AACR

    Star Formation in Cold, Spherical, Magnetized Molecular Clouds

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    We present an idealized, spherical model of the evolution of a magnetized molecular cloud due to ambipolar diffusion. This model allows us to follow the quasi-static evolution of the cloud's core prior to collapse and the subsequent evolution of the remaining envelope. By neglecting the thermal pressure gradients in comparison with magnetic stresses and by assuming that the ion velocity is small compared with the neutral velocity, we are able to find exact analytic solutions to the MHD equations. We show that, in the case of a centrally condensed cloud, a core of finite mass collapses into the origin leaving behind a quasi-static envelope, whereas initially homogeneous clouds never develop any structure in the absence of thermal stresses, and collapse as a whole. Prior to the collapse of the core, the cloud's evolution is characterized by two phases: a long, quasi-static phase where the relevant timescale is the ambipolar diffusion time (treated in this paper), and a short, dynamical phase where the characteristic timescale is the free-fall time. The collapse of the core is an "outside-in" collapse. The quasi-static evolution terminates when the cloud becomes magnetically supercritical; thereafter its evolution is dynamical, and a singularity develops at the origin-a protostar. After the initial formation of the protostar, the outer envelope continues to evolve quasi-statically, while the region of dynamical infall grows with time-an "inside-out" collapse. We use our solution to estimate the magnetic flux trapped in the collapsing core and the mass accretion rate onto the newly formed protostar. Our results agree, within factors of order unity, with the numerical results of Fiedler & Mouschovias (1992) for the physical quantities in the midplane ofComment: 18 postscript figures Accepted by The Astrophysical Journa

    The Formation of the First Stars I. Mass Infall Rates, Accretion Disk Structure and Protostellar Evolution

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    We present a theoretical model for primordial star formation. First we describe the structure of the initial gas cores as virialized, quasi-hydrostatic objects in accord with recent high resolution numerical studies. The accretion rate can then be related to characteristic densities and temperatures that are set by the cooling properties of molecular hydrogen. We allow for rotation of the gas core, assuming angular momentum conservation inside the sonic point of the flow. In the typical case, most mass then reaches the star via an accretion disk. The structure of the inner region of this disk is described with the standard theory of viscous disks, but with allowance for the substantial energies absorbed in ionizing and dissociating the gas. The size of the protostar and its luminosity depend upon the accretion rate, the energetics of the accreting gas, and the ability of the radiation to escape from the stellar accretion shock. We combine these models for the infall rate, inner disk structure, and protostellar evolution to predict the radiation field that is the basis for radiative feedback processes acting against infall (Paper II). For realistic initial angular momenta, the photosphere of the protostar is much smaller and hotter than in the spherical case, leading to stronger radiative feedback at earlier stages in the evolution. In particular, once the star is older than its Kelvin-Helmholtz time, contraction towards the main sequence causes a rapid increase in ionizing and far-ultraviolet luminosity at masses ~30Msun in the fiducial case. Since the cores out of which the first stars formed were much more massive than 30Msun and since feedback is dynamically unimportant at lower masses, we conclude that the first stars should have had masses >~30Msun.Comment: 20 pages, Accepted to ApJ, some re-arrangement of text for improved clarit

    New Studies of the Pulsar Wind Nebula in the Supernova Remnant CTB 80

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    We investigated the kinematics of the pulsar wind nebula (PWN) associated with PSR B1951+32 in the old supernova remnant CTB 80 using the Fabry-Perot interferometer of the 6m Special Astrophysical Observatory telescope. In addition to the previously known expansion of the system of bright filaments with a velocity of 100-200km/s, we detected weak high-velocity features in the H-alpha line at least up to velocities of 400-450km/s. We analyzed the morphology of the PWN in the H-alpha, [SII], and [OIII] lines using HST data and discuss its nature. The shape of the central filamentary shell, which is determined by the emission in the [OIII] line and in the radio continuum, is shown to be consistent with the bow-shock model for a significant (about 60 degrees) inclination of the pulsar's velocity vector to the plane of the sky. In this case, the space velocity of the pulsar is twice higher than its tangential velocity, i.e., it reaches ~500 km/s, and PSR B1951+32 is the first pulsar whose line-of-sight velocity (of about 400 km/s) has been estimated from the PWN observations. The shell-like H-alpha-structures outside the bow shock front in the east and the west may be associated with both the pulsar's jets and the pulsar-wind breakthrough due to the layered structure of the extended CTB 80 shell.Comment: to appear in Astronomy Letters, 12 pages, 6 postscript figures, two in colour; for a version with high resolution figures see http://www.sao.ru/hq/grb/team/vkom/CTB80_fine.pd

    Angular Momentum and the Formation of Stars and Black Holes

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    The formation of compact objects like stars and black holes is strongly constrained by the requirement that nearly all of the initial angular momentum of the diffuse material from which they form must be removed or redistributed during the formation process. The mechanisms that may be involved and their implications are discussed for (1) low-mass stars, most of which probably form in binary or multiple systems; (2) massive stars, which typically form in clusters; and (3) supermassive black holes that form in galactic nuclei. It is suggested that in all cases, gravitational interactions with other stars or mass concentrations in a forming system play an important role in redistributing angular momentum and thereby enabling the formation of a compact object. If this is true, the formation of stars and black holes must be a more complex, dynamic, and chaotic process than in standard models. The gravitational interactions that redistribute angular momentum tend to couple the mass of a forming object to the mass of the system, and this may have important implications for mass ratios in binaries, the upper stellar IMF in clusters, and the masses of supermassive black holes in galaxies.Comment: Accepted by Reports on Progress in Physic
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