Primordial Non-Gaussianity: Baryon Bias and Gravitational Collapse of Cosmic String Wakes

I compute the 3-D non-linear evolution of gas and dark matter fluids in the neighbourhood of cosmic string wakes which are formed at high redshift ($z\simeq 2240$) for a ``realistic'' scenario of wake formation. These wakes are the ones which stand out most prominently as cosmological sheets and are expected to play a dominant r\^ole in the cosmic string model of structure formation. Employing a high-resolution 3-D hydrodynamics code to evolve these wakes until the present day yields results for the baryon bias generated in the inner wake region. I find that today, wakes would be $1.5 h^{-1}$ Mpc thick and contain a 70% excess in the density of baryons over the dark matter density in their centre. However, high density peaks in the wake region do not inherit a baryon enhancement. I propose a mechanism for this erasure of the baryon excess in spherically collapsed objects based on the geometry change around the collapsing region. Further, I present heuristic arguments for the consequences of this work for large scale structure in the cosmic string model and conclude that the peculiarities of wake formation are unlikely to have significant import on the discrepancy between power spectrum predictions and observations in this model. If one invokes the nucleosynthesis bound on $\Omega_b$ this could be seen as strengthening the case against $\Omega_m=1$ or for low Hubble constants.Comment: 21 pages, 7 figures, 2 tables, prepared with the AASTeX package. Minor modifications, results unchanged. ApJ in press, scheduled for Vol. 50

Gender Differences and Roles of Two Science Self-Efficacy Beliefs in Predicting Post-College Outcomes

The end of college is a key transition point when students prepare for the workforce or graduate school, and when competence beliefs that have been shaped throughout college play a particularly important role in decision-making processes. This study examined the roles of two competence beliefs, self-efficacy for scientific tasks and science academic self-efficacy, during the final year of college. A structural equation model was used to examine science research self-efficacy and science academic self-efficacy as predictors of post-graduation science career intentions and life satisfaction; prior achievement was also included as a predictor of competence beliefs and post-graduation outcomes. Findings indicated that both types of self-efficacy predicted career intentions and life satisfaction. To better understand the processes that contribute to gender gaps in certain science careers, gender differences in mean levels of self-efficacy and in the structural relations among the variables of interest were examined using multi-group analyses. Females reported lower academic self-efficacy, despite having similar levels of prior achievement and outcomes; structural relations also appeared to vary by gender. Results extend theoretical understanding of the roles of two distinct forms of self-efficacy and the potential mechanisms explaining gender gaps in science fields

Promoting Mental Health and Wellbeing with Men and Boys: What Works?

In May 2014 the Movember Foundation commissioned the Centre for Men’s Health, Leeds Beckett University, in collaboration with the Men’s Health Forum (England & Wales), to gather the current research evidence and practical (‘tacit’) knowledge about the core elements that make for successful work with boys and men around mental health promotion, early intervention and stigma reduction

Successful mental health promotion with men: evidence from 'tacit knowledge'

There remains significant concern about men’s mental health, particularly in terms of personal and societal barriers to help-seeking, negative coping mechanisms and high suicide rates. This paper presents findings from a multi-phase study looking at ‘what works’ in mental health promotion for men. Work here reports the collection and analysis of the tacit knowledge of those working within mental health promotion interventions for men. A ‘multiple hub and spoke’ approach was used to assist data collection. Thirteen key players, active in the men’s mental health field, half from the UK and half beyond, formed an Investigative Network collecting data, mainly through interviews, from wider geographical and professional community contexts where they had networks. The focus of data collection was on ‘what works’ in mental health promotion for men. Data was analysed using thematic analysis techniques. Findings suggest that settings which created safe male spaces acted to promote trust, reduce stigma and normalise men’s engagement in interventions. Embedding interventions within the communities of men being engaged, fully involving these men, and holding ‘male-positive’ values engendered familiarity and consolidated trust. Using ‘male-sensitive’ language and activity-based approaches allowed for positive expressions of emotions, facilitated social engagement, and provided a base for open communication. Appropriate partnerships were also seen as a necessary requirement for success and as crucial for maximising intervention impact. The importance of gender and ‘masculinity’ was apparent throughout these findings and taking time to understand gender could facilitate positive ways of working alongside men, increasing levels of engagement and successful outcomes

Molecular line CO (2→1) observations of ultraluminous IRAS galaxies

CO (J=2→1) observations of six ultraluminous IRAS galaxies are presented. Four of these galaxies have no previous CO J=2→1 data and two have no previous CO detections at all. Based on these observations, molecular hydrogen masses are estimated and range from 5x109 to 1.8x1010 M⊙. The present data follow the well established correlation that exists between the infrared luminosity LIR and the molecular mass content. The high values of the LIR/MH2 suggest either an increased star formation efficiency and / or an additional source of luminosity such as an active nucleus. The ratio R=(J=2→1)/(J=1→0) between the J=2→1 and 1→0 line temperatures, is examined next using our J=2→1 intensities and other published CO J=1→0 data. For Arp 220, Mrk 231, Mrk 273 R lies in the range 0.7 to 1.1; for IRAS 05189 the CO intensity and the ratio R were both found to have extremely low values. The low values of R≤1 found for all galaxies, suggest that the line profiles are dominated by emission coming from optically thick thermalized CO. Finally the line profiles are examined and compared to published models concerning the distribution and kinematics of the gas. Assuming that the CO is distributed in a disk as in normal spiral galaxies, then this region is probably concentrated towards the center of the galaxies

A deep ATCA 20cm radio survey of the AKARI Deep Field South near the South Ecliptic Pole

The results of a deep 20 cm radio survey at 20 cm are reported of the AKARI Deep Field South (ADF-S) near the South Ecliptic Pole (SEP), using the Australia Telescope Compact Array telescope, ATCA. The survey has 1 sigma detection limits ranging from 18.7--50 microJy per beam over an area of ~1.1 sq degrees, and ~2.5 sq degrees to lower sensitivity. The observations, data reduction and source count analysis are presented, along with a description of the overall scientific objectives, and a catalogue containing 530 radio sources detected with a resolution of 6.2" x 4.9". The derived differential source counts show a pronounced excess of sources fainter than ~1 mJy, consistent with an emerging population of star forming galaxies. Cross-correlating the radio with AKARI sources and archival data we find 95 cross matches, with most galaxies having optical R-magnitudes in the range 18-24 mag, and 52 components lying within 1" of a radio position in at least one further catalogue (either IR or optical). We have reported redshifts for a sub-sample of our catalogue finding that they vary between galaxies in the local universe to those having redshifts of up to 0.825. Associating the radio sources with the Spitzer catalogue at 24 microns, we find 173 matches within one Spitzer pixel, of which a small sample of the identifications are clearly radio loud compared to the bulk of the galaxies. The radio luminosity plot and a colour-colour analysis suggest that the majority of the radio sources are in fact luminous star forming galaxies, rather than radio-loud AGN. There are additionally five cross matches between ASTE or BLAST submillimetre galaxies and radio sources from this survey, two of which are also detected at 90 microns, and 41 cross-matches with submillimetre sources detected in the Herschel HerMES survey Public Data release.Comment: MNRAS accepted and in press 9 July 2012: 28 pages, 15 Figures, 17 Table

The Feedback-Regulated Growth of Black Holes and Bulges through Gas Accretion and Starbursts in Cluster Central Dominant Galaxies

We present an analysis of the growth of black holes through accretion and bulges through star formation in 33 galaxies at the centers of cooling flows. Most of these systems show evidence of cavities in the intracluster medium (ICM) inflated by radio jets emanating from their active galactic nuclei (AGN). We present a new and extensive analysis of X-ray cavities in these systems. We find that AGN are energetically able to balance radiative losses (cooling) from the ICM in more than half of our sample. Using a subsample of 17 systems, we examine the relationship between cooling and star formation. We find that the star formation rates are approaching or are comparable to X-ray and far UV limits on the rates of gas condensation onto the central galaxy. The remaining radiative losses could be offset by AGN feedback. The vast gulf between radiative losses and the sink of cooling material, which has been the primary objection to cooling flows, has narrowed and, in some cases, is no longer a serious issue. Using the cavity (jet) powers, we place strong lower limits on the rate of growth of supermassive black holes in central galaxies, and we find that they are growing at an average rate of ~ 0.1 solar masses per year, with some systems growing as quickly as ~ 1 solar mass per year. We find a trend between bulge growth (star formation) and black hole growth that is approximately in accordance with the slope of the local (Magorrian) relation between black hole and bulge mass. However, the large scatter in the trend suggests that bulges and black holes do not always grow in lock step. (Abridged)Comment: 17 pages, 6 figures, accepted to ApJ. Minor changes to text and figure