Bringing Elites Sociology Back in European Integration Theories: A Case Study Based on Commissioners and Directors General

Founded on an analysis of biographies and carriers of top‐rank officials and members of the European Commission, this paper suggest that a lot of recent polemic within the EU Institutions (such as Verheugen controversy, Kinnock reform, etc.) are the expressions of the tensions originating from socio‐morphological transformations. To put it simply, the gap between the members and the officials of the Commission has never been so wide on this score. Commissioners seem to be gaining in political capitals to the detriment of a professional commitment in European politics, which implies for example a minimum degree of attendance in the political space of the EU or the accumulation of capitals relating to this space. Conversely, the top‐level officials increasingly appear to owe their positions to long‐term investment in institutions involving the production and, simultaneously, the accumulation of European capitals, a general tendency whereof the meaning is precisely questioned within the conjuncture of the Kinnock reform and more widely that of the political issues which characterised the mid 2000s. Beyond the conventional issue of the differentiation or de‐differentiation processes of the political and administrative elites, this approach enables to underline the unique relationship between these staff categories in the case of the EU and to point out, to a greater extent, an opposition between temporary and intermittent staff which seems to be a correct indicator of inequal objectivation process of the European institutions

Searching for X-ray luminous 'normal' galaxies in 2dfGRS

We cross-correlated the Chandra XASSIST and XMM-Newton Serendipitous Source Catalogues with the 2 degree Field Galaxy Redshift Survey (2dfGRS) database. Our aim was to identify the most X-ray luminous (L_X > 10^42 erg s^-1) examples of galaxies in the local Universe whose X-ray emission is dominated by stellar processes rather than AGN activity ('normal' galaxies) as well as to test the empirical criterion log(f_X/f_O) < -2 for separating AGN from NGs. With XMM-Newton (Chandra) we covered an area of ~8.2 (~5.8)deg^2 down to a flux limit of ~10^-15 (~1.6 x 10^-15) erg cm^-2 s^-1 and found 18 (20) 2dfGRS galaxies. Using emission-line intensity ratios, we classified 6 2dfGRS spectra as star-forming, H II nuclei, and 2 spectra as possible H II nuclei. The rest of the objects are absorption-line galaxies and AGN, including 3 possible LINERs. No luminous 'normal' galaxies have been found but out of 19 'normal' galaxies in this sample 5 H II and 3 absorption-line galaxies have log(f_X/f_O) > -2. We performed a similar search in two nearby-galaxy samples from the literature. All 44 galaxies in the Zezas (2001) sample have log(f_X/f_O) < -2 and L_X < 10^42 erg s^-1. In the Fabbiano et al. (1992) sample, out of a total of 170 'normal' galaxies, we found 16 galaxies with log(f_X/f_O) >-2, the majority of which are massive ellipticals. Three of these have L_X > 10^42 erg s^-1 .Comment: 8 pages, 2 figures. Accepted for publication in Astronomy & Astrophysic

NAVI: Novel authentication with visual information

Text-based passwords, despite their well-known drawbacks, remain the dominant user authentication scheme implemented. Graphical password systems, based on visual information such as the recognition of photographs and / or pictures, have emerged as a promising alternative to the aggregate reliance on text passwords. Nevertheless, despite the advantages offered they have not been widely used in practice since many open issues need to be resolved. In this paper we propose a novel graphical password scheme, NAVI, where the credentials of the user are his username and a password formulated by drawing a route on a predefined map. We analyze the strength of the password generated by this scheme and present a prototype implementation in order to illustrate the feasibility of our proposal. Finally, we discuss NAVI’s security features and compare it with existing graphical password schemes as well as text-based passwords in terms of key security features, such aspassword keyspace, dictionary attacks and guessing attacks. The proposed scheme appears to have the same or better performance in the majority of the security features examined

The Phoenix survey: the pairing fraction of faint radio sources

The significance of tidal interactions in the evolution of the faint radio population (sub-mJy) is studied using a deep and homogeneous radio survey (1.4 GHz), covering an area of 3.14 deg$^2$ and complete to a flux density of 0.4 mJy. Optical photometric and spectroscopic data are also available for this sample. A statistical approach is employed to identify candidate physical associations between radio sources and optically selected `field' galaxies. We find an excess of close pairs around optically identified faint radio sources, albeit at a low significance level, implying that the pairing fraction of the sub-mJy radio sources is similar to that of `field' galaxies (at the same magnitude limit) but higher than that of local galaxies.Comment: 5 pages, 4 figures. Accepted for publication in MNRAS Letter

X-rays across the galaxy population - III. The incidence of AGN as a function of star formation rate

We map the co-eval growth of galaxies and their central supermassive black holes in detail by measuring the incidence of Active Galactic Nuclei (AGN) in galaxies as a function of star formation rate (SFR) and redshift (to z~4). We combine large galaxy samples with deep Chandra X-ray imaging to measure the probability distribution of specific black hole accretion rates (LX relative to stellar mass) and derive robust AGN fractions and average specific accretion rates. First, we consider galaxies along the main sequence of star formation. We find a linear correlation between the average SFR and both the AGN fraction and average specific accretion rate across a wide range in stellar mass ($M_* \sim 10^{8.5-11.5}M_\odot$) and to at least z~2.5, indicating that AGN in main-sequence galaxies are driven by the stochastic accretion of cold gas. We also consider quiescent galaxies and find significantly higher AGN fractions than predicted, given their low SFRs, indicating that AGN in quiescent galaxies are fuelled by additional mechanisms (e.g. stellar winds). Next, we bin galaxies according to their SFRs relative to the main sequence. We find that the AGN fraction is significantly elevated for galaxies that are still star-forming but with SFRs below the main sequence, indicating further triggering mechanisms enhance AGN activity within these sub-main-sequence galaxies. We also find that the incidence of high-accretion-rate AGN is enhanced in starburst galaxies and evolves more mildly with redshift than within the rest of the galaxy population, suggesting mergers play a role in driving AGN activity in such high-SFR galaxies.Comment: 19 pages, 15 figures. This is a pre-copyedited, author-produced version of an article accepted for publication in MNRAS following peer revie

The radio spectra of reddened 2MASS QSOs: evidence for young radio jets

Multifrequency radio continuum observations (1.4-22 GHz) of a sample of reddened QSOs are presented. We find a high incidence (13/16) of radio spectral properties, such as low frequency turnovers, high frequency spectral breaks or steep power-law slopes, similar to those observed in powerful compact steep spectrum (CSS) and gigahertz-peaked spectrum (GPS) sources. The radio data are consistent with relatively young radio jets with synchotron ages <1e6-1e7yr. This calculation is limited by the lack of high resolution (milli-arcsec) radio observations. For the one source in the sample that such data are available a much younger radio age is determined, <2e3yr, similar to those of GPS/CSS sources. These findings are consistent with claims that reddened QSOs are young systems captured at the first stages of the growth of their supermassive black holes. It also suggests that expanding radio lobes may be an important feedback mode at the early stages of the evolution of AGN.Comment: 9 pages, to appear in MNRA

XMM and Chandra measurements of the AGN intrinsic absorption: dependence on luminosity and redshift

We combine bright XMM data with the Chandra Deep Field South observations in order to explore the behavior of the intrinsic AGN absorption, as a function of redshift and luminosity.Our sample consists of 359 sources selected in the hard 2-8 keV band, spanning the flux range 6\times10^{-16}-$3\times10^{-13} erg s^-1 cm^-2 with a high rate of spectroscopic or photometric redshift completeness (100 and 85 per cent respectively for the Chandra and XMM data. We derive the column density values using X-ray spectral fits. We find that the fraction of obscured AGN falls with increasing luminosity in agreement with previous findings. The fraction of obscured AGN shows an apparent increase at high redshifts (z>2). Simulations show that this effect can be most probably attributed to the fact that at high redshifts the column densities are overestimated.Comment: 14 pages, 9 figures, A&A accepte

The Clustering of XMM-Newton Hard X-ray Sources

We present the clustering properties of hard (2-8 keV) X-ray selected sources detected in a wide field (~2 deg^{2}) shallow [f(2-8 keV)~ 10^{-14} erg cm^{-2} s^{-1}] and contiguous XMM-Newton survey. We perform an angular correlation function analysis using a total of 171 sources to the above flux limit. We detect a ~ 4\sigma correlation signal out to 300 arcsec with w(theta < 300^{''}) ~ 0.13 +- 0.03. Modeling the two point correlation function as a power law of the usual form we find: theta_o=48.9^{+15.8}_{-24.5} arcsec and gamma=2.2 +- 0.30. Fixing the correlation function slope to gamma=1.8 we obtain theta_o=22.2^{+9.4}_{-8.6} arcsec. Using Limber's integral equation and a variety of possible luminosity functions of the hard X-ray population, we find a relatively large correlation length, ranging from r_o ~ 9 to 19 h^{-1} Mpc (for gamma=1.8 and the concordance cosmological model), with this range reflecting also different evolutionary models for the source luminosities and clustering characteristics.Comment: In "Multiwavelength AGN Surveys" (Cozumel, December 8-12 2003), ed. R. Maiolino and R. Mujica, Singapore: World Scientific, 200

Cold gas and star formation in a merging galaxy sequence

We explore the evolution of the cold gas and star-formation activity during galaxy interactions, using a merging galaxy sequence comprising both pre- and post-mergers. Data for this study come from the literature but supplemented by new radio observations presented here. Firstly, we confirm that the star-formation efficiency (SFE) increases close to nuclear coalescence. At post-merger stages there is evidence that the SFE declines to values typical of ellipticals. This trend can be attributed to M(H_2) depletion due to interaction induced star-formation. However, there is significant scatter, likely to arise from differences in the interaction details of individual systems. Secondly, we find that the central molecular hydrogen surface density, increases close to the final stages of the merging of the two nuclei. Such a trend is also predicted by numerical simulations. Furthermore, there is evidence for a decreasing fraction of cold gas mass from early interacting systems to merger remnants, attributed to gas conversion into other forms. The evolution of the total-radio to blue-band luminosity ratio, reflecting the disk+nucleus star-formation activity, is also investigated. Although this ratio is on average higher than that of isolated spirals, we find a marginal increase along the merging sequence, attributed to the relative insensitivity of disk star-formation to interactions. However, a similar result is also obtained for the nuclear radio emission, although galaxy interactions are believed to significantly affect the activity in the central galaxy regions. Finally, we find that the FIR--radio flux ratio distribution of interacting galaxies is consistent with star-formation being the main energising source.Comment: 18 pages, 17 figures, accepted for publication in MNRA