1,710 research outputs found

    Construction and Import of Ethnic Categorisations: “Allochthones” in The Netherlands and Belgium

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    Schematically one can distinguish two traditions related to ethnic statistics in Europe. In France, Germany and most southern European countries, the dominant statistical categorisations merely distinguish individuals on the basis of their nationality. In contrast, most northern European countries have been producing data on the ethnic and/or foreign origin of their populations. Belgium is caught somewhere in between these two traditions. The French speaking part of Belgium tends to follow the French tradition of refusing ethnic categorisation, while the Flemish (the Dutch speaking part) try to copy the Dutch model in distinguishing “allochthones” and “autochthones”. This contribution wants to offer an analysis of the construction of ethnic categories as it has been undertaken in the Dutch context. It equally wants to shed light on how the category of “allochthones” has been (partially) imported into the Belgian context and what the consequences are.Ethnic Categorisation, Statistics, “Allochthones”, the Netherlands, Belgium

    Les ambivalences de l’État social-sécuritaire

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    L’article envisage le changement du paradigme des politiques publiques liées à l’insécurité en milieu urbain. À l’encontre de ceux qui voient l’émergence d’un État pénal se substituant à l’État social, l’article soutient, à partir de l’étude de la situation existant en Belgique, que les nouvelles politiques urbaines reposent sur un changement de paradigme de certaines politiques publiques. La pacification urbaine, paradigme de ce qui qualifie l’action de l’État social-sécuritaire, repose sur des mesures visant simultanément à la sécurisation des personnes et des espaces publics et à la réaffiliation sociale dans les territoires résidentiels précarisés. Les nouvelles politiques urbaines produisent de la régulation sociale tout en inscrivant leur rôle un cadre normatif renouvelé du contrôle social.This article identifies a public policy paradigm change related to insecurity in urban settings. While some describe a penal state replacing the social state, this article instead claims, drawing on the Belgian case, that new urban policies mark a shift towards a paradigm that emphasises both security and the social. Urban peace is the goal of this paradigm, with programmes being designed both to make persons and public places safe and to maintain social cohesion in marginal residential areas. These urban policies involve social regulation via new norms of social control

    Discovery of a strongly phase-variable spectral feature in the isolated neutron star RX J0720.4-3125

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    We present the discovery of a strongly phase-variable absorption feature in the X-ray spectrum of the nearby, thermally-emitting, isolated neutron star RX J0720.4-3125. The absorption line was detected performing detailed phase-resolved spectroscopy in 20 XMM-Newton observations, covering the period May 2000 - September 2012. The feature has an energy of ~750eV, an equivalent width of ~30eV, and it is significantly detected for only ~20% of the pulsar rotation. The absorption feature appears to be stable over the timespan covered by the observations. Given its strong dependence on the pulsar rotational phase and its narrow width, a plausible interpretation is in terms of resonant proton cyclotron absorption/scattering in a confined magnetic structure very close to the neutron star surface. The inferred field in such a magnetic loop is B_loop ~ 2 x 10^{14} G, a factor of ~7 higher than the surface dipolar magnetic field.Comment: 6 pages, 4 figures; ApJ Letters accepte

    Magnetar-like activity from the central compact object in the SNR RCW103

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    The 6.67 hr periodicity and the variable X-ray flux of the central compact object (CCO) at the center of the SNR RCW 103, named 1E 161348-5055, have been always difficult to interpret within the standard scenarios of an isolated neutron star or a binary system. On 2016 June 22, the Burst Alert Telescope (BAT) onboard Swift detected a magnetar-like short X-ray burst from the direction of 1E 161348-5055, also coincident with a large long-term X-ray outburst. Here we report on Chandra, NuSTAR, and Swift (BAT and XRT) observations of this peculiar source during its 2016 outburst peak. In particular, we study the properties of this magnetar-like burst, we discover a hard X-ray tail in the CCO spectrum during outburst, and we study its long-term outburst history (from 1999 to July 2016). We find the emission properties of 1E 161348-5055 consistent with it being a magnetar. However in this scenario, the 6.67 hr periodicity can only be interpreted as the rotation period of this strongly magnetized neutron star, which therefore represents the slowest pulsar ever detected, by orders of magnitude. We briefly discuss the viable slow-down scenarios, favoring a picture involving a period of fall-back accretion after the supernova explosion, similarly to what is invoked (although in a different regime) to explain the "anti-magnetar" scenario for other CCOs.Comment: 6 pages, 3 figures. To be published in the Astrophysical Journal Letters; replaced to match the version accepted for publication on 2016 August 1

    Magnetars' Giant Flares: the case of SGR 1806-20

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    We first review on the peculiar characteristics of the bursting and flaring activity of the Soft Gamma-ray Repeaters and Anomalous X-ray Pulsars. We then report on the properties of the SGR 1806-20's Giant Flare occurred on 2004 December 27th, with particular interest on the pre and post flare intensity/hardness correlated variability. We show that these findings are consistent with the picture of a twisted internal magnetic field which stresses the star solid crust that finally cracks causing the giant flare (and the observed torsional oscillations). This crustal fracturing is accompanied by a simplification of the external magnetic field with a (partial) untwisting of the magnetosphere.Comment: 6 pages, 2 figures; accepted for publication in the Chinese Journal for Astronomy and Astrophysics (Vulcano conference - 2005

    Multi-wavelength observations of the transitional millisecond pulsar binary XSSJ12270-4859

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    We present an analysis of X-ray, Ultraviolet and optical/near-IR photometric data of the transitional millisecond pulsar binary XSSJ12270-4859, obtained at different epochs after the transition to a rotation-powered radio pulsar state. The observations, while confirming the large-amplitude orbital modulation found in previous studies after the state change, also reveal an energy dependence of the amplitudes as well as variations on time scale of months. The amplitude variations are anti-correlated in the X-ray and the UV/optical bands. The average X-ray spectrum is described by a power law with \Gamma index of 1.07(8) without requiring an additional thermal component. The power law index \Gamma varies from 1.2 to 1.0 between superior and inferior conjunction of the neutron star. We interpret the observed X-ray behaviour in terms of synchrotron radiation emitted in an extended intrabinary shock, located between the pulsar and the donor star, which is eclipsed due to the companion orbital motion. The G5 type donor dominates the UV/optical and near-IR emission and is similarly found to be heated up to ? 6500K as in the disc state. The analysis of optical light curves gives a binary inclination 46 < i < 65deg and a mass ratio 0.11 < q <0.26. The donor mass is found to be 0.15 < M2 < 0.36Msun for a neutron star mass of 1.4Msun. The variations in the amplitude of the orbital modulation are interpreted in terms of small changes in the mass flow rate from the donor star. The spectral energy distribution from radio to gamma-rays is composed by multiple contributions that are different from those observed during the accretion-powered state.Comment: 10 pages, 8 figures, 1 table Accepted for publication in Monthly Notices Royal Astronomical Society, Main Journa

    Filtrate seaweed extract as biostimulant in nursery organic horticulture

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    Many naturally-derived products are used as growth promoters or biostimulants on vegetables, even if their mechanisms of action are not still now completely clarified. Among them, seaweeds and seaweed products are inserted as admissible organic fertilizers in the Annex I of the Reg. (EC) No. 889/2008, even if their biostimulant properties are not recognized in organic farming. After a previous bioassay on maize germination for defining the optimal water dilution ratios of the filtrate seaweed extract (FSE), in the present research we applied the FSE at two diluted doses to a greenhouse organic lettuce, for assessing its biostimulant effect on vegetable growth and nutrient uptake. The greenhouse pot trials were conducted on Lactuca sativa L., by applying FSE at 1/250 and 1/500 v/v water dilutions. After 90 days, root fresh/dry weight, shoot fresh/dry weight and dry matter, number of leaves, LAI, specific leaf fresh/dry weight, total dry biomass, leaf macro and micro elements (P, K, Ca, Mg, Fe, Na, Mn, Cu, Zn, B) content and total chlorophyll were determined. Obtained results indicated that FSE plays a role in promoting the increase of lettuce shoot dry weight and related nutrient uptake, with particular efficacy in relation to P and K macroelements. This property is better expressed at the highest dilution, confirming that the biostimulating activity of the formulate acts without any nutritional effect: thus, the FSE appears to be a good opportunity for promoting the early-stage development for organic nursery productio

    A variable absorption feature in the X-ray spectrum of a magnetar

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    Soft gamma-ray repeaters (SGRs) and anomalous X-ray pulsars (AXPs) are slowly rotating, isolated neutron stars that sporadically undergo episodes of long-term flux enhancement (outbursts) generally accompanied by the emission of short bursts of hard X-rays. This behaviour can be understood in the magnetar model, according to which these sources are mainly powered by their own magnetic energy. This is supported by the fact that the magnetic fields inferred from several observed properties of AXPs and SGRs are greater than - or at the high end of the range of - those of radio pulsars. In the peculiar case of SGR 0418+5729, a weak dipole magnetic moment is derived from its timing parameters, whereas a strong field has been proposed to reside in the stellar interior and in multipole components on the surface. Here we show that the X-ray spectrum of SGR 0418+5729 has an absorption line, the properties of which depend strongly on the star's rotational phase. This line is interpreted as a proton cyclotron feature and its energy implies a magnetic field ranging from 2E14 gauss to more than 1E15 gauss.Comment: Nature, 500, 312 (including Supplementary Information
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