Identification of members in the central and outer regions of galaxy clusters

The caustic technique measures the mass of galaxy clusters in both their virial and infall regions and, as a byproduct, yields the list of cluster galaxy members. Here we use 100 galaxy clusters with mass M200>=1E14 Msun/h extracted from a cosmological N-body simulation of a LambdaCDM universe to test the ability of the caustic technique to identify the cluster galaxy members. We identify the true three-dimensional members as the gravitationally bound galaxies. The caustic technique uses the caustic location in the redshift diagram to separate the cluster members from the interlopers. We apply the technique to mock catalogues containing 1000 galaxies in the field of view of 12 Mpc/h on a side at the cluster location. On average, this sample size roughly corresponds to 180 real galaxy members within 3r200, similar to recent redshift surveys of cluster regions. The caustic technique yields a completeness, the fraction of identified true members, fc=0.95 (+- 0.03) within 3r200. The contamination increases from fi=0.020 (+0.046;-0.015) at r200 to fi=0.08 (+0.11;-0.05) at 3r200. No other technique for the identification of the members of a galaxy cluster provides such large completeness and small contamination at these large radii. The caustic technique assumes spherical symmetry and the asphericity of the cluster is responsible for most of the spread of the completeness and the contamination. By applying the technique to an approximately spherical system obtained by stacking the individual clusters, the spreads decrease by at least a factor of two. We finally estimate the cluster mass within 3r200 after removing the interlopers: for individual clusters, the mass estimated with the virial theorem is unbiased and within 30 per cent of the actual mass; this spread decreases to less than 10 per cent for the spherically symmetric stacked cluster.Comment: 13 pages, 10 figures, published on Ap

Assessing the widening age gap in British partisanship:The impact of values, maturation, and political mobilization

In Britain, age has traditionally been a strong predictor of vote choice, with older people much more likely to vote for the Conservatives and younger people much more likely to vote for Labour or the Liberal Democrats. Remarkably, this age gap has increased consistently over the last three general elections and was also well reflected in the 2016 EU membership referendum, with younger voters much more likely to support Remain over Leave, leading scholars and polling agencies alike to note that age appears to have become the new distinctive cleavage in voting behaviour. This thesis contributes to the growing interest in this field of research by examining how age-related characteristics influence electoral choices from three different perspectives. The project comprises three research papers. Using over time British Election Study data, the first paper examines the link between age, education, and liberal-authoritarian and left-right values. The second paper considers the influence of life-cycle effects and tests the impact of the delayed transition into adulthood on Conservative voting. The third paper shifts the focus to the supply-side and using a specially designed survey experiment tests the impact of political appeals directed at younger cohorts on the age gap in party support

Identification of galaxy cluster substructures with the Caustic method

We investigate the power of the caustic technique for identifying substructures of galaxy clusters from optical redshift data alone. The caustic technique is designed to estimate the mass profile of galaxy clusters to radii well beyond the virial radius, where dynamical equilibrium does not hold. Two by-products of this technique are the identification of the cluster members and the identification of the cluster substructures. We test the caustic technique as a substructure detector on two samples of 150 mock redshift surveys of clusters; the clusters are extracted from a large cosmological $N$-body simulation of a $\Lambda$CDM model and have masses of $M_{200} \sim 10^{14} h^{-1} M_{\odot}$ and $M_{200} \sim 10^{15} h^{-1} M_{\odot}$ in the two samples. We limit our analysis to substructures identified in the simulation with masses larger than $10^{13} h^{-1} M_{\odot}$. With mock redshift surveys with 200 galaxies within $3R_{200}$, (1) the caustic technique recovers $\sim 30-50$\% of the real substructures, and (2) $\sim 15-20$\% of the substructures identified by the caustic technique correspond to real substructures of the central cluster, the remaining fraction being low-mass substructures, groups or substructures of clusters in the surrounding region, or chance alignments of unrelated galaxies. These encouraging results show that the caustic technique is a promising approach for investigating the complex dynamics of galaxy clusters.Comment: 13 pages, 15 figures. Accepted for publication in Ap

Feminism and disability

Las mujeres con discapacidad se encuentran bajo, al menos, una doble discriminación y exclusión social, en cuanto mujeres y en cuanto personas con discapacidad. Para realizar un análisis profundo de la situación real de las mujeres con discapacidad, es necesario comprender cuáles han sido los modelos que pueden darle una respuesta político-jurídica. Así, se identifica el modelo feminista, en donde se pretende indagar acerca de la posible conexión, o no, con el modelo social de la discapacidad. En el balance que arroja este análisis se repara en la relevancia y en lo acertado del pensamiento feminista cuando aborda la cuestión de la desigualdad entre el hombre y la mujer, pero se lo observa incompleto respecto a la mujer con discapacidad como parte de este movimiento.Women with disabilities are under a double discrimination and social exclusion as women and as persons with disabilities. To perform a thorough and critical analysis of women with disabilities situation, it’s necessary to understand what models can give a political and legal response. In this perspective, can be identified the feminist movement, which is intended to inquire about the possible connection, or not, between social model of disability and the feminist movement itself. This critical analysis repaired in the exactness and relevance of the feminist theory when addressing the issue of inequality between men and women, but observes an incomplete study regarding women with disabilities as part of this movement

Hacia una protección efectiva de los derechos humanos de niños y niñas en el conflicto armado

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Toxicity and residual activity of spinetoram to neonate larvae of Grapholita molesta (Busck) and Cydia pomonella (L.) (Lepidoptera: Tortricidae): Semi-field and laboratory trials

Spinetoram is a fermentation insecticide, derived from the actinomycete Saccharopolyspora spinosa. It works by disrupting the GABA-gated chloride channels and by causing persistent activation of insect nicotinic acetylcholine receptors. This study aimed to evaluate the efficacy of spinetoram for control of neonate larvae of both oriental fruit moth (OFM) Grapholita molesta (Busck) and codling moth (CM) Cydia pomonella (L.) in semi-field and laboratory trials. OFM and CM neonate larvae responded similarly to spinetoram, which showed high efficacy on both species. In semi-field experiments, regression analysis of the percentage of damaged fruits as a function of days after treatment showed a better performance of the highest spinetoram dose (10 g a.i./hl) in comparison with the maximum recommended field dose of the reference product emamectin benzoate (2.85 g a.i./hl). Surface-treated diet assays revealed LC50 values of 6.59 and 8.44 ng a.i./cm2 for neonate larvae of OFM and CM larvae, respectively. High percentages of mortality were recorded on both species after 24-h exposure to treated diet. For these reasons spinetoram could be considered a valuable tool in IPM strategies for OFM and CM control

The mass accretion rate of galaxy clusters: a measurable quantity

We explore the possibility of measuring the mass accretion rate (MAR) of galaxy clusters from their mass profiles beyond the virial radius $R_{200}$. We derive the accretion rate from the mass of a spherical shell whose inner radius is $2R_{200}$, whose thickness changes with redshift, and whose infall velocity is assumed to be equal to the mean infall velocity of the spherical shells of dark matter halos extracted from $N$-body simulations. This approximation is rather crude in hierarchical clustering scenarios where both smooth accretion and aggregation of smaller dark matter halos contribute to the mass accretion of clusters.Nevertheless, in the redshift range $z=[0,2]$, our prescription returns an average MAR within $20-40 \%$ of the average rate derived from the merger trees of dark matter halos extracted from $N$-body simulations. The MAR of galaxy clusters has been the topic of numerous detailed numerical and theoretical investigations, but so far it has remained inaccessible to measurements in the real universe. Since the measurement of the mass profile of clusters beyond their virial radius can be performed with the caustic technique applied to dense redshift surveys of the cluster outer regions, our result suggests that measuring the mean MAR of a sample of galaxy clusters is actually feasible. We thus provide a new potential observational test of the cosmological and structure formation models.Comment: 11 pages, 7 figures, 5 tables, minor text modifications to match the published version, typos correcte