Probability distribution of density fluctuations in the non-linear regime

We present a general procedure for obtaining the present density fluctuation probability distribution given the statistics of the initial conditions. The main difficulties faced with regard to this problem are those related to the non-linear evolution of the density fluctuations and those posed by the fact that the fields we are interested in are the result of filtering an underlying field with structure down to scales much smaller than that of filtering. The solution to the latter problem is discussed here in detail and the solution to the former is taken from a previous work. We have checked the procedure for values of the rms density fluctuation as large as 3/2 and several power spectra and found that it leads to results in excellent agreement with those obtained in numerical simulations. We also recover all available exact results from perturbation theory.Comment: Accepted to be published in Ap

Virial theorem in clusters of galaxies with MOND

A specific modification of Newtonian dynamics known as MOND has been shown to reproduce the dynamics of most astrophysical systems at different scales without invoking non-baryonic dark matter (DM). There is, however, a long-standing unsolved problem when MOND is applied to rich clusters of galaxies in the form of a deficit (by a factor around two) of predicted dynamical mass derived from the virial theorem with respect to observations. In this article we approach the virial theorem using the velocity dispersion of cluster members along the line of sight rather than using the cluster temperature from X-ray data and hydrostatic equilibrium. Analytical calculations of the virial theorem in clusters for Newtonian gravity+DM and MOND are developed, applying pressure (surface) corrections for non-closed systems. Recent calibrations of DM profiles, baryonic ratio and baryonic ($\beta$ model or others) profiles are used, while allowing free parameters to range within the observational constraints. It is shown that solutions exist for MOND in clusters that give similar results to Newton+DM -- particularly in the case of an isothermal $\beta$ model for $\beta =0.55-0.70$ and core radii $r_c$ between 0.1 and 0.3 times $r_{500}$ (in agreement with the known data). The disagreements found in previous studies seem to be due to the lack of pressure corrections (based on inappropriate hydrostatic equilibrium assumptions) and/or inappropriate parameters for the baryonic matter profiles.Comment: accepted to be published in MNRA

Statistical Tests for CHDM and \LambdaCDM Cosmologies

We apply several statistical estimators to high-resolution N-body simulations of two currently viable cosmological models: a mixed dark matter model, having $\Omega_\nu=0.2$ contributed by two massive neutrinos (C+2\nuDM), and a Cold Dark Matter model with Cosmological Constant (\LambdaCDM) with $\Omega_0=0.3$ and h=0.7. Our aim is to compare simulated galaxy samples with the Perseus-Pisces redshift survey (PPS). We consider the n-point correlation functions (n=2-4), the N-count probability functions P_N, including the void probability function P_0, and the underdensity probability function U_\epsilon (where \epsilon fixes the underdensity threshold in percentage of the average). We find that P_0 (for which PPS and CfA2 data agree) and P_1 distinguish efficiently between the models, while U_\epsilon is only marginally discriminatory. On the contrary, the reduced skewness and kurtosis are, respectively, S_3\simeq 2.2 and S_4\simeq 6-7 in all cases, quite independent of the scale, in agreement with hierarchical scaling predictions and estimates based on redshift surveys. Among our results, we emphasize the remarkable agreement between PPS data and C+2\nuDM in all the tests performed. In contrast, the above \LambdaCDM model has serious difficulties in reproducing observational data if galaxies and matter overdensities are related in a simple way.Comment: 12 pages, 10 figures, LaTeX (aaspp4 macro), in press on ApJ, Vol. 479, April 199

Biases in galaxy cluster velocity dispersion and mass estimates in the small number of galaxies regime

We present a study of the statistical properties of three velocity dispersion and mass estimators, namely biweight, gapper and standard deviation, in the small number of galaxies regime ($N_{\rm gal} \le 75$). Using a set of 73 numerically simulated galaxy clusters, we characterise the statistical bias and the variance for the three estimators, both in the determination of the velocity dispersion and the dynamical mass of the clusters via the $\sigma-M$ relation. The results are used to define a new set of unbiased estimators, that are able to correct for those statistical biases with a minimal increase of the associated variance. The numerical simulations are also used to characterise the impact of velocity segregation in the selection of cluster members, and the impact of using cluster members within different physical radii from the cluster centre. The standard deviation is found to be the lowest variance estimator. The selection of galaxies within the sub-sample of the most massive galaxies in the cluster introduces a $2\,$\% bias in the velocity dispersion estimate when calculated using a quarter of the most massive cluster members. We also find a dependence of the velocity dispersion estimate on the aperture radius as a fraction of $R_{200}$, consistent with previous results. The proposed set of unbiased estimators effectively provides a correction of the velocity dispersion and mass estimates from all those effects in the small number of cluster members regime. This is tested by applying the new estimators to a subset of simulated observations. Although for a single galaxy cluster the statistical and physical effects discussed here are comparable or slightly smaller than the bias introduced by interlopers, they will be of relevance when dealing with ensemble properties and scaling relations for large cluster samples (Abridged).Comment: accepted for publication in A&

Promoting a compassionate motivation in detained youth: A secondary analysis of a controlled trial with the PSYCHOPATHY.COMP program

This study aims to assess the efficacy of the PSYCHOPATHY.COMP in promoting a compassionate motivation among male detained youth, also testing its role as a potential mechanism of change on the reduction of psychopathic traits. A treatment group (n = 58) and a control group (n = 61) answered a set of self-report measures on psychopathic traits, shame, fears of compassion, social safeness, self-compassion, and compassion for others at three timepoints: baseline, posttreatment, and 6 months’ follow-up. Treatment participants attended the PSYCHOPATHY.COMP. Controls received the treatment as usual delivered at juvenile detention facilities. The treatment effects were tested with latent growth curve models. At baseline, no significant differences between groups were found. Results from latent growth curve models showed that condition was a significant predictor of change over time observed in all outcome measures, even after controlling for psychopathic traits scores. When compared with the control group, the treatment group showed a significant decrease on shame and fears of compassion and a significant increase on social safeness, self-compassion, and compassion for others over time (medium-to-large effect sizes; growth modeling analysis d ranging from .57 to .96). It was also observed that increases in self-compassion and, in some cases, decreases in fears of receiving compassion, were crucial to the decrease of psychopathic traits. These findings suggest that the PSYCHOPATHY.COMP is a promising approach to promote a compassionate motivation in these youth, strengthening their rehabilitation odds. Increasing self-compassion and decreasing fears of receiving compassion should be considered when designing intervention programs for detained youth.

Incidencia de liquen escleroso en 617 circuncisiones

El liquen escleroatrófico es un transtorno crónico de la piel de causa desconocida que puede aparecer en la región genital sobre todo en varones de mediana edad no circuncidados y que se relaciona con el cáncer de pene. Su incidencia varía en función de las series

Virtual Enterprise integration management based on a Meta-enterprise - A PMBoK approach

A Virtual Enterprise (VE) can be viewed as a project, with a lifecycle corresponding to the period between its creation and integration of the constituting elements until its dissolution, comprehending its operation and including its reconfigurations. The authors propose that the VE lifecycle is aligned and can be managed using the frameworks provided by several bodies of knowledge, such as the PMBoK Guide. In this paper the authors propose an alignment referential between the Project Management phases defined by PMBoK and management processes during the VE lifecycle.This work has been supported by (1) COMPETE: POCI-01-0145-FEDER-007043 (2) FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio

A prescription for the conditional mass function of dark matter haloes

[ABRIDGED] The unconditional mass function (UMF) of dark matter haloes has been determined accurately in the literature, showing excellent agreement with high resolution numerical simulations. However, this is not the case for the conditional mass function (CMF). We propose a simple analytical procedure to derive the CMF by rescaling the UMF to the constrained environment using the appropriate mean and variance of the density field at the constrained point. This method introduces two major modifications with respect to the standard re-scaling procedure. First of all, rather than using in the scaling procedure the properties of the environment averaged over all the conditioning region, we implement the re-scaling locally. We show that for high masses this modification may lead to substantially different results. Secondly, we modify the (local) standard re-scaling procedure in such a manner as to force normalisation, in the sense that when one integrates the CMF over all possible values of the constraint multiplied by their corresponding probability distribution, the UMF is recovered. In practise, we do this by replacing in the standard procedure the value delta_c (the linear density contrast for collapse) by certain adjustable effective parameter delta_eff. In order to test the method, we compare our prescription with the results obtained from numerical simulations in voids (Gottlober et al. 2003), finding a very good agreement. Based on these results, we finally present a very accurate analytical fit to the (accumulated) conditional mass function obtained with our procedure, which may be useful for any theoretical treatment of the large scale structure.Comment: 14 pages, 10 figures. Accepted for publication in MNRA

Making sense of violence risk predictions using clinical notes

Violence risk assessment in psychiatric institutions enables interventions to avoid violence incidents. Clinical notes written by practitioners and available in electronic health records (EHR) are valuable resources that are seldom used to their full potential. Previous studies have attempted to assess violence risk in psychiatric patients using such notes, with acceptable performance. However, they do not explain why classification works and how it can be improved. We explore two methods to better understand the quality of a classifier in the context of clinical note analysis: random forests using topic models, and choice of evaluation metric. These methods allow us to understand both our data and our methodology more profoundly, setting up the groundwork for improved models that build upon this understanding. This is particularly important when it comes to the generalizability of evaluated classifiers to new data, a trustworthiness problem that is of great interest due to the increased availability of new data in electronic format

Parental smoking and child poverty in the UK: an analysis of national survey data

BACKGROUND: In 2011/12 approximately 2.3 million children, 17% of children in the UK, were estimated to be in relative poverty. Cigarette smoking is expensive and places an additional burden on household budgets, and is strongly associated with socioeconomic deprivation. The aim of this study was to provide an illustrative first estimate of the extent to which parental smoking exacerbates child poverty in the UK. METHODS: Findings from the 2012 Households Below Average Income report and the 2012 Opinions and Lifestyle Survey were combined to estimate the number of children living in poor households containing smokers; the expenditure of typical smokers in these households on tobacco; and the numbers of children drawn into poverty if expenditure on smoking is subtracted from household income. RESULTS: 1.1 million children - almost half of all children in poverty - were estimated to be living in poverty with at least one parent who smokes; and a further 400,000 would be classed as being in poverty if parental tobacco expenditure were subtracted from household income. CONCLUSIONS: Smoking exacerbates poverty for a large proportion of children in the UK. Tobacco control interventions which effectively enable low income smokers to quit can play an important role in reducing the financial burden of child poverty