30 research outputs found

    Off-the-Cuff Law-Making: Policing Pandemic Dispossession in Spain

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    This article presents a discussion concerning the role of police rationale(s) in Spain within the context of the Covid-19 pandemic, where exceptionalist strategies aimed at curtailing the spread of the virus came to dramatically strengthen existing social divisions. In line with some authors who have already approached this phenomenon from different disciplines, our premise is that most serious emergencies boosted by Covid-19 were not a mere matter of public health, but rather a particularly harmful expression of accumulation by dispossession. Thus, rather than a flaw in the system produced by an exceptional friction between public security and public health, securitarian performances deployed by neoliberal states can be read as symbiotic strategies, from both law and order and business as usual approaches, to manage the social “externalities” of capitalist predatory strategies. As we will argue, phenomena such as the reinforcement of the policing consensus, police production of law, or the authoritarian turn favored by the Covid-19 health crisis must all be analyzed in this context

    Consensus on community guidelines: an experimental study on the legitimacy of content removal in social media

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    The popularization of social media has led to a considerable increase in the importance of discursive expressions of violence, especially when directed at vulnerable communities. While social media platforms have created rules to regulate such expressions, little information is available on the perception of the legitimacy of these rules in the general population, regardless of the importance of the former for the latter. It is therefore the objective of this study to analyze the perception of the seriousness of such content and the degree to which the population has established a consensus on the withdrawal of restricted discursive behaviour on three major social media platforms (Facebook, Instagram and Twitter). For this purpose, 918 participants were immersed in an experimental paradigm in three different groups (n1 = 302; n2 = 301; n3 = 315). Each was presented with stimuli containing discursive behaviour that is banned by community guidelines. The stimuli were presented differently to each group (i.e., description of the banned behaviour, description and accompanying example, example only). Our experimental data reveals that the degree of consensus on the need to remove content is quite high, regardless of the style of presentation. It furthermore suggests that the behaviour in question is perceived as very serious, due to the harm that our participants presume it to cause. These results have important implications for the debate on freedom of expression on the Internet and its regulation by private actors

    Media representation of minors who migrate on their own: The 'MENA' in the Spanish press

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    This article analyses Spanish media treatment of a certain type of immigrant: the unaccompanied foreign minor ('MENA' in Spanish). The media play an important role in creating and disseminating ideas and images amongst the general public, thereby promoting the articulation of sets of meanings called discourses. The main goal of this research is to identify the discursive approaches that have been constructed around the term “MENA” in the main Spanish daily newspapers. To this end, we gathered and analysed all the news reports published between January 2017 and October 2019 by the digital editions of the four most widely-read newspapers in Spain (La Vanguardia, El País, El Mundo and ABC). This analysis was performed using text mining techniques (an important field in data science) such as term frequency, inverse document frequency, and correlation networks between words. Our results show that the term “MENA” evokes a criminalising, moralistic, welfare-dependent discourse that is articulated from an adult-centric, nationalist perspective. The study concluded that the conservative press uses the acronym more frequently than the left-wing media. However, no significant discursive differences were observed between conservative and progressive press in terms of the language used, which often had negative connotations that stigmatised the young people concerned

    La opinión pública colombiana sobre el acuerdo de paz 2016-2020: punitivismo, desconfianza y ostracismo

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    Después de varias décadas de conflicto armado en Colombia, el Gobierno colombiano y las Farc-EP firmaron, en 2016, el Acuerdo Final para la terminación del conflicto y la construcción de una paz estable y duradera. No obstante, este acuerdo no fue refrendado por la ciudadanía, en un plebiscito celebrado ese mismo año. En 2018, ganó las elecciones presidenciales un candidato que prometió cambiar las condiciones del Acuerdos Final y modificar uno de sus principales instrumentos: la Jurisdicción Especial para la Paz (JEP). En ese contexto esta investigación se pregunta: ¿cuál es la opinión de los colombianos sobre el Acuerdo Final y la JEP? La investigación indaga en las opiniones de los colombianos a través de un análisis estadístico comparativo de tres encuestas de opinión de 2016, 2018 y 2020. Los resultados detallan los cambios actitudinales ocurridos en esos años, como la disminución del rechazo frontal a los Acuerdos de Paz y el leve incremento de las posibilidades de reintegración de los excombatientes a la vida civil. También, expone algunas reticencias al cambio, como la desconfianza persistente, la reafirmación del rechazo al indulto de los excombatientes (punitivismo) y a su participación política (ostracismo)

    Formation of stellar inner discs and rings in spiral galaxies through minor mergers

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    Recent observations show that inner disks and rings (IDs and IRs) are not preferentially found in barred galaxies, pointing to the relevance of formation mechanisms different to the traditional bar-origin scenario. Nevertheless, the role of minor mergers in the formation of these inner components (ICs), while often invoked, is still poorly understood. We have investigated the capability of minor mergers to trigger the formation of IDs and IRs in spiral galaxies through collisionless N-body simulations. Our models prove that minor mergers are an efficient mechanism to form rotationally-supported stellar ICs in spirals, neither requiring strong dissipation nor noticeable bars, and suggest that their role in the formation of ICs must have been much more complex than just bar triggering

    I. MUFFIT: A multi-filter fitting code for stellar population diagnostics

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    Numerical methods and codes.-- et al.[Aims]: We present MUFFIT, a new generic code optimized to retrieve the main stellar population parameters of galaxies in photometric multi-filter surveys, and check its reliability and feasibility with real galaxy data from the ALHAMBRA survey. [Methods]: Making use of an error-weighted X2-test, we compare the multi-filter fluxes of galaxies with the synthetic photometry of mixtures of two single stellar populations at different redshifts and extinctions, to provide the most likely range of stellar population parameters (mainly ages and metallicities), extinctions, redshifts, and stellar masses. To improve the diagnostic reliability, MUFFIT identifies and removes from the analysis those bands that are significantly affected by emission lines. The final parameters and their uncertainties are derived by a Monte Carlo method, using the individual photometric uncertainties in each band. Finally, we discuss the accuracies, degeneracies, and reliability of MUFFIT using both simulated and real galaxies from ALHAMBRA, comparing with results from the literature. [Results]: MUFFIT is a precise and reliable code to derive stellar population parameters of galaxies in ALHAMBRA. Using the results from photometric-redshift codes as input, MUFFIT improves the photometric-redshift accuracy by ∼10-20%. MUFFIT also detects nebular emissions in galaxies, providing physical information about their strengths. The stellar masses derived from MUFFIT show excellent agreement with the COSMOS and SDSS values. In addition, the retrieved age-metallicity locus for a sample of z ≤ 0.22 early-type galaxies in ALHAMBRA at different stellar mass bins are in very good agreement with the ones from SDSS spectroscopic diagnostics. Moreover, a one-to-one comparison between the redshifts, ages, metallicities, and stellar masses derived spectroscopically for SDSS and by MUFFIT for ALHAMBRA reveals good qualitative agreements in all the parameters, hence reinforcing the strengths of multi-filter galaxy data and optimized analysis techniques, like MUFFIT, to conduct reliable stellar population studies.L.A.D.G. acknowledges support from the "Caja Rural de Teruel" for developing this research. A.J.C. is a Ramon y Cajal Fellow of the Spanish Ministry of Science and Innovation. This work has been supported by the "Programa Nacional de Astronomia y Astrofisica" of the Spanish Ministry of Economy and Competitiveness (MINECO) under grant AYA2012-30789, as well as by FEDER funds and the Government of Aragon, through the Research Group E103. L.A.D.G. also thanks the Mullard Space Science Laboratory (MSSL) and Royal Astronomical Society (RAS) for offering the opportunity to support and develop part of this research in collaboration with I.F. MINECO grants AYA2010-15081, AYA2010-15169, AYA2010-22111-C03-01, AYA2010-22111-C03-02, AYA2011-29517-C03-01, AYA2013-40611-P, AYA2013-42227-P, AYA2013-43188-P, AYA2013-48623-C2-1, AYA2013-48623-C2-2, and AYA2014-58861-C3-1 are also acknowledged, together with Generalitat Valenciana projects Prometeo 2009/064 and PROMETEOII/2014/060, and Junta de Andalucia grants TIC114, JA2828, and P10-FQM-6444. MP acknowledges financial support from the JAE-Doc programme of the Spanish National Research Council (CSIC), co-funded by the European Social Fund.Peer Reviewe

    The ALHAMBRA survey: Estimation of the clustering signal encoded in the cosmic variance

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    [Aims]: The relative cosmic variance (σv) is a fundamental source of uncertainty in pencil-beam surveys and, as a particular case of count-in-cell statistics, can be used to estimate the bias between galaxies and their underlying dark-matter distribution. Our goal is to test the significance of the clustering information encoded in the σv measured in the ALHAMBRA survey. [Methods]: We measure the cosmic variance of several galaxy populations selected with B-band luminosity at 0.35 ≤ z< 1.05 as the intrinsic dispersion in the number density distribution derived from the 48 ALHAMBRA subfields. We compare the observational σv with the cosmic variance of the dark matter expected from the theory, σv,dm. This provides an estimation of the galaxy bias b. [Results]: The galaxy bias from the cosmic variance is in excellent agreement with the bias estimated by two-point correlation function analysis in ALHAMBRA. This holds for different redshift bins, for red and blue subsamples, and for several B-band luminosity selections. We find that b increases with the B-band luminosity and the redshift, as expected from previous work. Moreover, red galaxies have a larger bias than blue galaxies, with a relative bias of brel = 1.4 ± 0.2. [Conclusions]: Our results demonstrate that the cosmic variance measured in ALHAMBRA is due to the clustering of galaxies and can be used to characterise the σv affecting pencil-beam surveys. In addition, it can also be used to estimate the galaxy bias b from a method independent of correlation functions.This work has been mainly funded by the FITE (Fondos de Inversiones de Teruel) and the projects AYA2012-30789, AYA2006-14056, and CSD2007-00060. We also acknowledge support from the Spanish Ministry for Economy and Competitiveness and FEDER funds through grants AYA2010-15081, AYA2010-15169, AYA2010-22111-C03-01, AYA2010-22111-C03-02, AYA2011-29517-C03-01, AYA2012-39620, AYA2013-40611-P, AYA2013-42227-P, AYA2013-43188-P, AYA2013-48623-C2-1, AYA2013-48623-C2-2, ESP2013-48274, AYA2014-58861-C3-1, Aragon Government Research Group E103, Generalitat Valenciana projects Prometeo 2009/064 and PROMETEOII/2014/060, Junta de Andalucia grants TIC114, JA2828, P10-FQM-6444, and Generalitat de Catalunya project SGR-1398. A.J.C. and C.H.-M. are Ramon y Cajal fellows of the Spanish government. A. M. acknowledges the financial support of the Brazilian funding agency FAPESP (Post-doc fellowship - process number 2014/11806-9). M.P. acknowledges financial support from JAE-Doc program of the Spanish National Research Council (CSIC), co-funded by the European Social Fund.Peer Reviewe

    The ALHAMBRA survey: Bayesian photometric redshifts with 23 bands for 3 deg2

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    A. Molino et al.The Advance Large Homogeneous Area Medium-Band Redshift Astronomical (ALHAMBRA) survey has observed eight different regions of the sky, including sections of the Cosmic Evolution Survey (COSMOS), DEEP2, European Large-Area Infrared Space Observatory Survey (ELAIS), Great Observatories Origins Deep Survey North (GOODS-N), Sloan Digital Sky Survey (SDSS) and Groth fields using a new photometric system with 20 optical, contiguous ~300-Å filters plus the JHKs bands. The filter system is designed to optimize the effective photometric redshift depth of the survey, while having enough wavelength resolution for the identification of faint emission lines. The observations, carried out with the Calar Alto 3.5-m telescope using the wide-field optical camera Large Area Imager for Calar Alto (LAICA) and the near-infrared (NIR) instrument Omega-2000, represent a total of ~700 h of on-target science images. Here we present multicolour point-spread function (PSF) corrected photometry and photometric redshifts for ~438 000 galaxies, detected in synthetic F814W images. The catalogues are complete down to a magnitude I~24.5AB and cover an effective area of 2.79 deg2. Photometric zero-points were calibrated using stellar transformation equations and refined internally, using a new technique based on the highly robust photometric redshifts measured for emission-line galaxies. We calculate Bayesian photometric redshifts with the Bayesian Photometric Redshift (BPZ)2.0 code, obtaining a precision of δz/(1+zs)=1 per cent for I<22.5 and δz/(1+zs)=1.4 per cent for 22.5<I<24.5. The global n(z) distribution shows a mean redshift 〈z〉=0.56 for I<22.5 AB and 〈z〉=0.86 for I<24.5 AB. Given its depth and small cosmic variance, ALHAMBRA is a unique data set for galaxy evolution studies. © 2014 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.We acknowledge financial support from the Spanish MICINN under the Consolider-Ingenio 2010 Program grant CSD2006-00070: First Science with the GTC. Part of this work was supported by Junta de Andalucía, through grant TIC-114 and the Excellence Project P08-TIC-3531, and by the Spanish Ministry for Science and Innovation through grants AYA2006-1456, AYA2010-15169, AYA2010-22111-C03-02, AYA2010-22111-C03-01 and Generalitat Valenciana project Prometeo 2009/064.Peer Reviewe

    The ALHAMBRA survey: accurate merger fractions derived by PDF analysis of photometrically close pairs

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    [Aims]: Our goal is to develop and test a novel methodology to compute accurate close-pair fractions with photometric redshifts. [Methods]: We improved the currently used methodologies to estimate the merger fraction fm from photometric redshifts by (i) using the full probability distribution functions (PDFs) of the sources in redshift space; (ii) including the variation in the luminosity of the sources with z in both the sample selection and the luminosity ratio constrain; and (iii) splitting individual PDFs into red and blue spectral templates to reliably work with colour selections.We tested the performance of our new methodology with the PDFs provided by the ALHAMBRA photometric survey. [Results]: The merger fractions and rates from the ALHAMBRA survey agree excellently well with those from spectroscopic work for both the general population and red and blue galaxies. With the merger rate of bright (MB ≤ -20 - 1:1z) galaxies evolving as (1 + z)n, the power-law index n is higher for blue galaxies (n = 2:7 0:5) than for red galaxies (n = 1:3 0:4), confirming previous results. Integrating the merger rate over cosmic time, we find that the average number of mergers per galaxy since z = 1 is Nm red = 0:57 0:05 for red galaxies and Nm blue = 0:26 0:02 for blue galaxies. [Conclusions]: Our new methodology statistically exploits all the available information provided by photometric redshift codes and yields accurate measurements of the merger fraction by close pairs from using photometric redshifts alone. Current and future photometric surveys will benefit from this new methodology.This work has been mainly funded by the FITE (Fondos de Inversiones de Teruel) and the projects AYA2012-30789, AYA2006-14056, and CSD2007-00060. We also acknowledge financial support from the Spanish Government grants AYA2010-15169, AYA2010-22111-C03-01, AYA2010-22111-C03-02, and AYA2013-48623-C2-2, from the Aragón Government through the Research Group E103, from the Junta de Andalucía through TIC-114 and the Excellence Project P08-TIC-03531, and from the Generalitat Valenciana through the projects Prometeo/2009/064 and PrometeoII/2014/060. A.J.C. is Ramón y Cajal fellow of the Spanish government. M.P. acknowledges the financial support from JAE-Doc program of the Spanish National Research Council (CSIC), co-funded by the European Social Fund.Peer Reviewe
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