478 research outputs found
Denunciation and the construction of norms in group conflict: examples from an Al-Qaeda-supporting group
In situations of violent group conflict, group members often argue about how to deal with the outgroup. While some argue for aggression, force and separation, others argue for negotiation and cooperation. Each side attempts to persuade the group that their own position is normative and is most in line with the interests and essence of the group. These arguments often involve denunciations of opponents as disloyal or deviant. In such situations, definitions of group identities and norms, and what counts as loyalty and deviance, are therefore disputed. This paper analyses how a UK-based Al-Qaeda-supporting organisation denounces ‘moderate’ Muslims in the UK who engage with secular institutions and who ally themselves with non-Muslims in political disputes. Drawing on theological, historical and political arguments, a prescriptive norm is constructed whereby the correct behaviour of Muslims in the West is to avoid participation in secular political systems and to avoid political cooperation with non-Muslims. Muslims who are seen as breaking these norms are denounced and denigrated in a variety of ways by assigning them a range of deviant identity positions. Denunciations involve explanatory accounts which construct opponents as unworthy representatives of the group based on their deviation from Islam, or from ignorance, cowardice, mental weakness or self-interest. This paper illustrates that the practice of denunciation is an important aspect of the organisation of group conflict. Finally, it argues that it is dangerous for social psychologists to treat group norms and protoypes as consensual
Variations of training load, monotony, and strain and dose-response relationships with maximal aerobic speed, maximal oxygen uptake, and isokinetic strength in professional soccer players
This study aimed to identify variations in weekly training load, training monotony, and training strain across a 10-week period (during both, pre- and in-season phases); and to analyze the dose-response relationships between training markers and maximal aerobic speed (MAS), maximal oxygen uptake, and isokinetic strength. Twenty-seven professional soccer players (24.9±3.5 years old) were monitored across the 10-week period using global positioning system units. Players were also tested for maximal aerobic speed, maximal oxygen uptake, and isokinetic strength before and after 10 weeks of training. Large positive correlations were found between sum of training load and extension peak torque in the right lower limb (r = 0.57, 90%CI[0.15;0.82]) and the ratio agonist/antagonist in the right lower limb (r = 0.51, [0.06;0.78]). It was observed that loading measures fluctuated across the period of the study and that the load was meaningfully associated with changes in the fitness status of players. However, those magnitudes of correlations were small-to-large, suggesting that variations in fitness level cannot be exclusively explained by the accumulated load and loading profile
Near-IR Search for Lensed Supernovae Behind Galaxy Clusters - II. First Detection and Future Prospects
Powerful gravitational telescopes in the form of massive galaxy clusters can
be used to enhance the light collecting power over a limited field of view by
about an order of magnitude in flux. This effect is exploited here to increase
the depth of a survey for lensed supernovae at near-IR wavelengths. A pilot SN
search program conducted with the ISAAC camera at VLT is presented. Lensed
galaxies behind the massive clusters A1689, A1835 and AC114 were observed for a
total of 20 hours split into 2, 3 and 4 epochs respectively, separated by
approximately one month to a limiting magnitude J<24 (Vega). Image subtractions
including another 20 hours worth of archival ISAAC/VLT data were used to search
for transients with lightcurve properties consistent with redshifted
supernovae, both in the new and reference data. The feasibility of finding
lensed supernovae in our survey was investigated using synthetic lightcurves of
supernovae and several models of the volumetric Type Ia and core-collapse
supernova rates as a function of redshift. We also estimate the number of
supernova discoveries expected from the inferred star formation rate in the
observed galaxies. The methods consistently predict a Poisson mean value for
the expected number of SNe in the survey between N_SN=0.8 and 1.6 for all
supernova types, evenly distributed between core collapse and Type Ia SN. One
transient object was found behind A1689, 0.5" from a galaxy with photometric
redshift z_gal=0.6 +- 0.15. The lightcurve and colors of the transient are
consistent with being a reddened Type IIP SN at z_SN=0.59. The lensing model
predicts 1.4 magnitudes of magnification at the location of the transient,
without which this object would not have been detected in the near-IR ground
based search described in this paper (unlensed magnitude J~25). (abridged)Comment: Accepted by AA, matches journal versio
Broad-line Balmer Decrements in Blue Active Galactic Nuclei
We have investigated the broad-line Balmer decrements (Halpha/Hbeta) for a
large, homogeneous sample of Seyfert 1 galaxies and QSOs using spectroscopic
data obtained in the Sloan Digital Sky Survey. The sample, drawn from the
Fourth Data Release, comprises 446 low redshift (z < 0.35) active galactic
nuclei (AGN) that have blue optical continua as indicated by the spectral
slopes in order to minimize the effect of dust extinction. We find that (i) the
distribution of the intrinsic broad-line Halpha/Hbeta ratio can be well
described by log-Gaussian, with a peak at Halpha/Hbeta=3.06 and a standard
deviation of about 0.03 dex only; (ii) the Balmer decrement does not correlate
with AGN properties such as luminosity, accretion rate, and continuum slope,
etc.; (iii) on average, the Balmer decrements are found to be only slightly
larger in radio-loud sources (3.37) and sources having double-peaked
emission-line profiles (3.27) compared to the rest of the sample. We therefore
suggest that the broad-line Halpha/Hbeta ratio can be used as a good indicator
for dust extinction in the AGN broad-line region; this is especially true for
radio-quiet AGN with regular emission-line profiles, which constitute the vast
majority of the AGN population.Comment: To appear in MNRAS. The data and the fitted parameters for the
decomposed spectral components (continuum, FeII and other emission lines) of
the 446 blue AGNs are available at
http://staff.ustc.edu.cn/~xbdong/Data_Release/blueAGN_DR4
The Luminosity-Metallicity Relation of distant luminous infrared galaxies
One hundred and five 15mu selected objects in three ISO deep survey fields
(CFRS 3h, UDSR and UDSF) are studied on the basis of the high quality optical
spectra with resolution R>1000 from VLT/FORS2. Ninety two objects (88%) have
secure redshifts, ranging from 0 to 1.16 with a median value of 0.587.
Considerable care is taken in estimating the extinction property of individual
galaxy, which can seriously affect diagnostic diagrams and estimates of star
formation rates and of metal abundances. Two independent methods have been
adopted to estimate extinction, e.g. Balmer line ratio (A_V(Balmer)) and energy
balance between IR and Hbeta luminosities (A_V(IR)). For most of the z>0.4
luminous IR galaxies (LIRGs), the two extinction coefficients are consistent
well, with median values of A_V(IR) = 2.36. These distant LIRGs show many
properties strikingly in common with those of local (IRAS) LIRGs studied by
Veilleux et al. (1995). Our sample can provide a good representation of LIRGs
in the distant Universe. Most (>77%) ISO 15mu selected sample galaxies are
dominated by star formation. Oxygen abundances (12+log(O/H), derived from R23
and O32) in ISM in the distant LIRGs range from 8.36 to 8.93 with a median
value of 8.67. Distant LIRGs present a metal content less than half of that of
the local bright disks (i.e. L*). The Pegase2 models predict that total masses
(gas + stars) of the distant LIRGs are from 10^{11} Msun to <=10^{12} Msun. A
significant fraction of distant large disks are indeed LIRGs. Such massive
disks could have formed ~50% of their metals and stellar masses since z~1.Comment: 20 pages, 9 PS figures, Accepted for publication in A&
Quasi-stellar objects in the ALHAMBRA survey. I. Photometric redshift accuracy based on a 23 optical-NIR filter photometry
We characterize the ability of the ALHAMBRA survey to assign accurate
photo-z's to BLAGN and QSOs based on their ALHAMBRA very-low-resolution
optical-NIR spectroscopy. A sample of 170 spectroscopically identified BLAGN
and QSOs have been used together with a library of templates (including SEDs
from AGN, normal, starburst galaxies and stars) in order to fit the 23
photometric data points provided by ALHAMBRA in the optical and NIR (20
medium-band optical filters plus the standard JHKs). We find that the ALHAMBRA
photometry is able to provide an accurate photo-z and spectral classification
for ~88% of the spectroscopic sources over 2.5 deg^2 in different areas of the
survey, all of them brighter than m678=23.5 (equivalent to r(SLOAN)~24.0). The
derived photo-z accuracy is better than 1% and comparable to the most recent
results in other cosmological fields. The fraction of outliers (~12%) is mainly
caused by the larger photometric errors for the faintest sources and the
intrinsic variability of the BLAGN/QSO population. A small fraction of outliers
may have an incorrectly assigned spectroscopic redshift. The definition of the
ALHAMBRA survey in terms of the number of filters, filter properties, area
coverage and depth is able to provide photometric redshifts for BLAGN/QSOs with
a precision similar to any previous survey that makes use of medium-band
optical photometry. In agreement with previous literature results, our analysis
also reveals that, in the 0<z<4 redshift interval, very accurate photo-z can be
obtained without the use of near-IR broadband photometry at the expense of a
slight increase of outliers. The NIR importance is expected to increase at
higher redshifts (z>4). These results are relevant for the design of future
optical follow-ups of surveys with a large fraction of BLAGN, as it is the case
for X-rays or radio surveys.Comment: 17 pages, 12 figures. Accepted for publication in A&
Species identification by experts and non-experts: comparing images from field guides
Accurate species identification is fundamental when recording ecological data. However, the ability to correctly identify organisms visually is rarely questioned. We investigated how experts and non-experts compared in the identification of bumblebees, a group of insects of considerable conservation concern. Experts and non-experts were asked whether two concurrent bumblebee images depicted the same or two different species. Overall accuracy was below 60% and comparable for experts and non-experts. However, experts were more consistent in their answers when the same images were repeated, and more cautious in committing to a definitive answer. Our findings demonstrate the difficulty of correctly identifying bumblebees using images from field guides. Such error rates need to be accounted for when interpreting species data, whether or not they have been collected by experts. We suggest that investigation of how experts and non-experts make observations should be incorporated into study design, and could be used to improve training in species identification
The angular clustering of infrared-selected obscured and unobscured quasars
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. ©: 2014 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Recent studies of luminous infrared-selected active galactic nuclei (AGN) suggest that the reddest, most obscured objects display a higher angular clustering amplitude, and thus reside in higher mass darkmatter haloes. This is a direct contradiction to the prediction of the simplest unification-by-orientation models of AGN and quasars. However, clustering measurements depend strongly on the 'mask' that removes low-quality data and describes the sky and selection function.We find that applying a robust, conservative mask to WISE-selected quasars yields a weaker but still significant difference in the bias between obscured and unobscured quasars. These findings are consistent with results from previous Spitzer surveys, and removes any scale dependence of the bias. For obscured quasars with =0.99, we measure a bias of bq = 2.67 ± 0.16, corresponding to a halo mass of log(Mh/M⊙h-1) = 13.3 ± 0.1, while for unobscured sources with = 1.04 we find bq = 2.04 ± 0.17 with a halo mass log(Mh/M⊙h-1) = 12.8 ± 0.1. This improved measurement indicates that WISE-selected obscured quasars reside in haloes only a few times more massive than the haloes of their unobscured counterparts, a reduction in the factor of ∼10 larger halo mass as has been previously reported using WISE-selected samples. Additionally, an abundance matching analysis yields lifetimes for both obscured and unobscured quasar phases on the order of a few 100 Myr (∼1 per cent of the Hubble time) - however, the obscured phase lasts roughly twice as long, in tension with many model predictions.Peer reviewe
Gas absorption and dust extinction towards the Orion Nebula Cluster
B. Hasenberger, et al, 'Gas absorption and dust extinction towards the Orion Nebula Cluster', Astronomy & Astrophysics, 593, A7, 2016. The version of record is available online at DOI: 10.1051/0004-6361/201628517. Published by EDP Sciences. © ESO, 2016We characterise the relation between the gas and dust content of the interstellar medium towards young stellar objects in the Orion Nebula Cluster. X-ray observations provide estimates of the absorbing equivalent hydrogen column density N_H based on spectral fits. Near-infrared extinction values are calculated from intrinsic and observed colour magnitudes (J-H) and (H-K_s) as given by the VISTA Orion A survey. A linear fit of the correlation between column density and extinction values A_V yields an estimate of the N_H/A_V ratio. We investigate systematic uncertainties of the results by describing and (if possible) quantifying the influence of circumstellar material and the adopted extinction law, X-ray models, and elemental abundances on the N_H/A_V ratio. Assuming a Galactic extinction law with R_V=3.1 and solar abundances by Anders & Grevesse (1989), we deduce an N_H/A_V ratio of (1.39 +- 0.14) x 10^21 cm^-2 mag^-1 for Class III sources in the Orion Nebula Cluster where the given error does not include systematic uncertainties. This ratio is consistent with similar studies in other star-forming regions and approximately 31% lower than the Galactic value. We find no obvious trends in the spatial distribution of N_H/A_V ratios. Changes in the assumed extinction law and elemental abundances are demonstrated to have a relevant impact on deduced A_V and N_H values, respectively. Large systematic uncertainties associated with metal abundances in the Orion Nebula Cluster represent the primary limitation for the deduction of a definitive N_H/A_V ratio and the physical interpretation of these results.Peer reviewe
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