Constraining the Collisional Nature of the Dark Matter Through Observations of Gravitational Wakes

We propose to use gravitational wakes as a direct observational probe of the collisional nature of the dark matter. We calculate analytically the structure of a wake generated by the motion of a galaxy in the core of an X-ray cluster for dark matter in the highly-collisional and collisionless limits. We show that the difference between these limits can be recovered from detailed X-ray or weak lensing observations. We also discuss the sizes of sub-halos in these limits. Preliminary X-ray data on the motion of NGC 1404 through the Fornax group disfavors fluid-like dark matter but does not exclude scenarios in which the dark matter is weakly collisional.Comment: 29 pages, 3 figures, submitted to Ap

Development of an Online Well-Being Intervention for Young People: An Evaluation Protocol

This is an open-access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work, first published in JMIR Research Protocols, is properly cited. The complete bibliographic information, a link to the original publication on http://www.researchprotocols.org, as well as this copyright and license information must be includedBackground: Research has shown that improving well-being using positive mental health interventions can be useful for predicting and preventing mental illness. Implementing online interventions may be an effective way to reach young people, given their familiarity with technology. Objective: This study will assess the effectiveness of a website called the “Online Wellbeing Centre (OWC),” designed for the support and improvement of mental health and well-being in young Australians aged between 16 and 25 years. As the active component of the study, the OWC will introduce a self-guided app recommendation service called “The Toolbox: The best apps for your brain and body” developed by ReachOut.com. The Toolbox is a responsive website that serves as a personalized, ongoing recommendation service for technology-based tools and apps to improve well-being. It allows users to personalize their experience according to their individual needs. Methods: This study will be a two-arm, randomized controlled trial following a wait-list control design. The primary outcome will be changes in psychological well-being measured by the Mental Health Continuum Short Form. The secondary outcomes will be drawn from a subsample of participants and will include depression scores measured by the Center for Epidemiologic Studies Depression Scale, and quality of life measured by the Assessment of Quality of Life-four dimensions (AQOL-4D) index. Cost-effectiveness analysis will be conducted based on a primary outcome of cost per unique visit to the OWC. Utility-based outcomes will also be incorporated into the analysis allowing a secondary outcome to be cost per quality-adjusted life year gained (based on the AQOL-4D values). Resource use associated with both the intervention and control groups will be collected using a customized questionnaire. Online- and community-based recruitment strategies will be implemented, and the effectiveness of each approach will be analyzed. Participants will be recruited from the general Australian population and randomized online. The trial will last for 4 weeks. Results: Small but clinically significant increases in well-being symptoms are expected to be detected in the intervention group compared with the control group

Towards an Understanding of the Globular Cluster Over--abundance around the Central Giant Elliptical NGC 1399

We investigate the kinematics of a combined sample of 74 globular clusters around NGC 1399. Their high velocity dispersion, increasing with radius, supports their association with the gravitational potential of the galaxy cluster rather than with that of NGC 1399 itself. We find no evidence for rotation in the full sample, although some indication for rotation in the outer regions. The data do not allow us to detect differences between the kinematics of the blue and red sub-populations of globular clusters. A comparison between the globular cluster systems of NGC 1399 and those of NGC 1404 and NGC 1380 indicates that the globular clusters in all three galaxies are likely to have formed via similar mechanisms and at similar epochs. The only property which distinguishes the NGC 1399 globular cluster system from these others is that it is ten times more abundant. We summarize the evidence for associating these excess globulars with the galaxy cluster rather than with NGC 1399 itself, and suggest that the over-abundance can be explained by tidal stripping, at an early epoch, of neighboring galaxies and subsequent accumulation of globulars in the gravitational potential of the galaxy cluster.Comment: AJ accepted (March issue), 27 pages (6 figures included), AAS style, two columns. Also available at http://www.eso.org/~mkissle

The promise and the reality: a mental health workforce perspective on technology-enhanced youth mental health service delivery

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Background: Digital technologies show promise for reversing poor engagement of youth (16–24 years) with mental health services. In particular, mobile and internet based applications with communication capabilities can augment face-to-face mental health service provision. The literature in this field, however, fails to adequately capture the perspectives of the youth mental health workforce regarding utility and acceptability of technology for this purpose. Methods: This paper describes results of in-depth qualitative data drawn from various stakeholders involved in provision of youth mental health services in one Australian rural region. Data were obtained using focus groups and semi-structured interviews with regional youth mental health clinicians, youth workers and support/management staff (n = 4 focus groups; n = 8 interviews) and analysed via inductive thematic analysis. Results: Results question the acceptability of technology to engage clients within youth mental health services. Six main themes were identified: young people in a digital age, personal connection, power and vulnerability, professional identity, individual factors and organisational legitimacy. Conclusions:These findings deepen the understanding of risks and challenges faced when adopting new technologies in mental healthcare. Recommendations for technology design and implementation in mental health services are made

NGC 1399: a complex dynamical case

Evidence for a disturbed velocity structure in the outer regions of the galaxy NGC1399 comes from a re-analysis of the planetary nebulae data from Arnaboldi et al. (1994). We find a strong rotation along a P.A.=140 degrees for R<=140'' which is followed by a rapid drop off at larger radii, where the velocity dispersion starts to increase. This kinematical behavior can be interpreted as an indication for an interaction scenario. Interaction is advocated in previous analysis of the halo regions of this system, based on different dynamical tracers such as globular clusters and X-rays, but in all these studies the mass distribution is derived under the equilibrium hypothesis, which is not appropriate when an interaction takes place. Here we attempt a non-equilibrium dynamical analysis of NGC1399: with a simple model and under the impulse approximation, we show that the observed kinematics is consistent with an energy injection caused by a flyby encounter of NGC 1399 with the nearby system NGC 1404. In this approach, we find a mass-to-light ratio, M/L_B=26 within R=400'', which is about half of that requested when equilibrium is assumed, i.e. M/L_B=56.Comment: 10 pages, 15 figures, accepted for pubblication in A&

The Globular Cluster System of NGC 1399. II. Kinematics of a Large Sample of Globular Clusters

We study the kinematics and dynamics of the globular cluster system of NGC 1399, the central galaxy of the Fornax cluster. The observational data consists of medium resolution spectra, obtained at the Very Large Telescope. Our sample comprises 468 radial velocities in the magnitude range 20 < m_R < 23. This is the largest sample of globular cluster velocities around any galaxy obtained so far. The radial range is 2 arcmin < r < 9 arcmin, corresponding to 11 kpc to 50 kpc of galactocentric distance. There is the possibility that unbound clusters and/or objects in the foreground contaminate the NGC 1399 cluster sample. Under strong error selection, practically no objects are found with velocities lower than 800 km/s or higher than 2000 km/s. Since the extreme velocities influence the velocity dispersion considerably, uncertainty regarding the exact value of the dispersion remains. Within the above velocity limits, we derive a projected velocity dispersion for the total sample of 274+-9 km/s which within the uncertainties remains constant over the entire radial range. Without any velocity restriction, it increases to 325 km/s. Blue and red clusters show different dispersions corresponding to their different surface density profiles. Spherical models point to a circular velocity of 415+-30$ km/s, assuming isotropy for the red clusters. This value is constant out to 40 kpc. The inferred dark halo potential can be well represented by a logarithmic potential. Also a halo of the NFW type fits well to the observations. Some mass profiles derived from X-ray analyses do not agree with a constant circular velocity within our radial range, irrespective of its exact value.Comment: 38 pages, 20 figures, accepted by A

VELOCITY DISTRIBUTIONS IN SPHERICAL ELLIPTIC GALAXIES .2. MEASURING LINE-OF-SIGHT STELLAR VELOCITY DISTRIBUTIONS.

A

Dying, a normal part of life: what learners see as the one thing they could change in the workplace to more appropriately provide end-of-life care

© Flinders University. This work is copyrighted. It may be reproduced in whole or in part for research or training purposes, subject to the inclusion of an acknowledgement of the source. It may not be reproduced for commercial use or sale. Reproduction for purposes other than those indicated above requires written permission from the Research Centre for Palliative Care, Death & Dying. Contact [email protected] for permissions.End-of-Life Essentials (EOLE) is a government funded project which aims to provide free peer-reviewed online education modules and implementation resources on end-of-life care to health professionals in acute hospitals in Australia. 'Dying, A Normal Part of Life' is an educational module featured in the suite of EOLE modules and includes education around the impact of end of life and dying on health care professionals working in acute hospitals, identifying common patterns of trajectories of dying, and discussing the reasons why dying in acute hospitals is often complex for professionals, patients, and families. This White Paper outlines and explores the results of the retrospective data analysis conducted for a two year period, 6th May 2017 to 5th May 2019. A total of 2232 learner statements responding to the free text response question posed at the end of the module: "Tomorrow, the one thing I can change to more appropriately provide end-of-life care is…" were extracted from the EOLE learning platform. The results identified the following themes as nominated practice change areas: Patient-centred care; Communication skills; Humanising healthcare; Recognise and talk about dying; Organisational factors