260 research outputs found
Star complexes and stellar populations in NGC 6822 - Comparison with the Magellanic Clouds
The star complexes (large scale star forming regions) of NGC 6822 were traced
and mapped and their size distribution was compared with the size distribution
of star complexes in the Magellanic Clouds (MCs). Furthermore, the spatial
distributions of different age stellar populations were compared with each
other. The star complexes of NGC 6822 were determined by using the isopleths,
based on star counts, of the young stars of the galaxy, using a statistical
cutoff limit in density. In order to map them and determine their geometrical
properties, an ellipse was fitted to every distinct region satisfying this
minimum limit. The Kolmogorov-Smirnov statistical test was used to study
possible patterns in their size distribution. Isopleths were also used to study
the stellar populations of NGC 6822. The star complexes of NGC 6822 were
detected and a list of their positions and sizes was produced. Indications of
hierarchical star formation, in terms of spatial distribution, time evolution
and preferable sizes were found in NGC 6822 and the MCs. The spatial
distribution of the various age stellar populations has indicated traces of an
interaction in NGC 6822, dated before 350 +/- 50 Myr.Comment: 10 pages, 7 figures, accepted by A&A; minor typeface correction
Structure of the SMC - Stellar component distribution from 2MASS data
The spatial distribution of the SMC stellar component is investigated from
2MASS data. The morphology of the different age populations is presented. The
center of the distribution is calculated and compared with previous
estimations. The rotation of the stellar content and possible consequence of
dark matter presence are discussed. The different stellar populations are
identified through a CMD diagram of the 2MASS data. Isopleth contour maps are
produced in every case, to reveal the spatial distribution. The derived density
profiles are discussed. The older stellar population follows an exponential
profile at projected diameters of about 5 kpc (~5 deg) for the major axis and
~4 kpc for the minor axis, centred at RA: 0h:51min, Dec: -73deg 7' (J2000.0).
The centre coordinates are found the same for all the different age population
maps and are in good accordance with the kinematical centre of the SMC. However
they are found considerably different from the coordinates of the centre of the
gas distribution. The fact that the older population found on an exponential
disk, gives evidence that the stellar content is rotating, with a possible
consequence of dark matter presence. The strong interactions between the MCs
and the MilkyWay might explain the difference in the distributions of the
stellar and gas components. The lack in the observed velocity element, that
implies absence of rotation, and contradicts with the consequences of
exponential profile of the stellar component, may also be a result of the
gravitational interactions.Comment: 7 Pages, 6 figures, accepted for publication in A&
Exploring the experiences of people vlogging about severe mental illness on YouTube: An interpretative phenomenological analysis
© 2018 Elsevier B.V. Background: Evidence suggests that, compared to the general population, individuals with severe mental illness (SMI) are more likely to engage in online social networking and share personal experiences through blogging. However, little is known about the impact of creating and publicly sharing mental health videos (vlogging) on individuals with self-identified SMIs. Aims: The present study aims to investigate the experiences of individuals with self-identified SMIs who vlog about their SMI on YouTube. Methods: YouTube was systematically searched using four key search items (“schizophrenia”, “bipolar disorder”, “major depressive disorder” and “schizoaffective disorder”). After manually screening approximately 50 channels, a set of 30 videos by individuals with self-identified SMIs discussing their experience of vlogging was selected and transcribed verbatim. An interpretative phenomenological analysis (IPA) was employed for the analysis of the data. Results: The analysis produced three global themes: Minimising Isolation; Vlogging as Therapy; and Fighting stigma. Limitations: The data collected was limited as regards depth of content by the inability to ask follow-up questions. Conclusions: The findings suggest that engaging in the act of vlogging about mental illness may benefit and encourage recovery in individuals with SMIs by providing them with peer support, enhancing self-efficacy, and reducing self-stigma. Future research should employ interviews to produce more robust data for analysis
Spatial distribution of stellar populations in the Magellanic Clouds: Implementation to Gaia
The main goal of our project is to investigate the spatial distribution of
different stellar populations in the Magellanic Clouds. The results from
modelling the Magellanic Clouds can be useful, among others, for simulations
during the Gaia mission preparation. Isodensity contour maps have been used in
order to trace the morphology of the different stellar populations and estimate
the size of these structures. Moreover, star density maps are constructed
through star counts and projected radial density profiles are obtained. Fitting
exponential disk and King law curves to the spatial distribution allows us to
derive the structural parameters that describe these profiles. The
morphological structure and spatial distributions of various stellar components
in the Magellanic Clouds (young and intermediate age stars, carbon stars) along
with the overall spatial distribution in both Clouds are provided.Comment: 12 pages, 9 figures, to be published in Astronomy & Astrophysics;
typos and language correcte
The development of ReGoal, a serious mobile game for young people with conduct problems*
Research suggests that serious games can be used as supplementary training tools for young people with complex mental health needs. This study aimed to co-produce a mobile-accessible serious game, ReGoal, in collaboration with young people (11–16 years) and an interdisciplinary team of academic experts and practitioners. ReGoal is aimed to serve as a supplementary tool for improving emotion regulation, goal-orientation, and executive functioning skills. This study consisted of three interlinked co-production phases. First, 122 participants, of which 34% had moderate to high conduct problems, completed an online survey about the role of gaming in managing their emotions. During the second phase, 16 young people attended three focus groups in which their lived experiences shaped the narrative of ReGoal. In the third phase, an online user survey gathered feedback from 72 young people playing the most recent prototype of ReGoal. The key findings suggest that young people valued playing ReGoal as a supplementary aid to improving their mood, increasing empathy towards peers and family, reducing anxiety, anger, and impulsivity, and understanding other people’s emotions. Future research should test the applicability and feasibility of ReGoal in reducing behavioural problems with clinical and non-clinical samples
Star Formation History in two fields of the Small Magellanic Cloud Bar
The Bar is the most productive region of the Small Magellanic Cloud in terms
of star formation but also the least studied one. In this paper we investigate
the star formation history of two fields located in the SW and in the NE
portion of the Bar using two independent and well tested procedures applied to
the color-magnitude diagrams of their stellar populations resolved by means of
deep HST photometry. We find that the Bar experienced a negligible star
formation activity in the first few Gyr, followed by a dramatic enhancement
from 6 to 4 Gyr ago and a nearly constant activity since then. The two examined
fields differ both in the rate of star formation and in the ratio of recent
over past activity, but share the very low level of initial activity and its
sudden increase around 5 Gyr ago. The striking similarity between the timing of
the enhancement and the timing of the major episode in the Large Magellanic
Cloud is suggestive of a close encounter triggering star formation.Comment: 30 pages, 22 figures, accepted for publication in Ap
Spitzer Analysis of HII Region Complexes in the Magellanic Clouds: Determining a Suitable Monochromatic Obscured Star Formation Indicator
HII regions are the birth places of stars, and as such they provide the best
measure of current star formation rates (SFRs) in galaxies. The close proximity
of the Magellanic Clouds allows us to probe the nature of these star forming
regions at small spatial scales. We aim to determine the monochromatic IR band
that most accurately traces the bolometric IR flux (TIR), which can then be
used to estimate an obscured SFR. We present the spatial analysis, via
aperture/annulus photometry, of 16 LMC and 16 SMC HII region complexes using
the Spitzer IRAC and MIPS bands. UV rocket data and SHASSA H-alpha data are
also included. We find that nearly all of the LMC and SMC HII region SEDs peak
around 70um, from ~10 to ~400 pc from the central sources. As a result, the
sizes of HII regions as probed by 70um is approximately equal to the sizes as
probed by TIR (about 70 pc in radius); the radial profile of the 70um flux,
normalized by TIR, is constant at all radii (70um ~ 0.45 TIR); the 1-sigma
standard deviation of the 70um fluxes, normalized by TIR, is a lower fraction
of the mean (0.05 to 0.12 out to ~220 pc) than the normalized 8, 24, and 160um
normalized fluxes (0.12 to 0.52); and these results are invariant between the
LMC and SMC. From these results, we argue that 70um is the most suitable IR
band to use as a monochromatic obscured star formation indicator because it
most accurately reproduces the TIR of HII regions in the LMC and SMC and over
large spatial scales. We also explore the general trends of the 8, 24, 70, and
160um bands in the LMC and SMC HII region SEDs, radial surface brightness
profiles, sizes, and normalized (by TIR) radial flux profiles. We derive an
obscured SFR equation that is modified from the literature to use 70um
luminosity, SFR(Mo/yr) = 9.7(0.7)x10^{-44} L(70)(ergs/s), which is applicable
from 10 to 300 pc distance from the center of an HII region.Comment: 21 pages, 12 figures, 4 tables. Will be published in ApJ
A systematic review of the psychometric properties, usability and clinical impacts of mobile mood-monitoring applications in young people
Background:
Mobile mood-monitoring applications are increasingly used by mental health providers, widely advocated within research, and a potentially effective method to engage young people. However, little is known about their efficacy and usability in young populations.
Method:
A systematic review addressing 3 research questions focused on young people: 1) what are the psychometric properties of mobile mood-monitoring applications; 2) what is their usability; and 3) what are their positive and negative clinical impacts? Findings were synthesised narratively, study quality assessed, and compared with evidence from adult studies.
Results:
We reviewed 25 articles. Studies on the psychometric properties of mobile mood-monitoring applications were sparse, but indicate questionable to excellent internal consistency, moderate concurrent validity, and good usability. Participation rates ranged from 30-99% across studies, and appeared to be affected by methodological factors (e.g., payments) and individual characteristics (e.g., IQ score). Mobile mood-monitoring applications are positively perceived by youth, may reduce depressive symptoms by increasing emotional awareness, and could aid in the detection of mental health and substance use problems. There was very limited evidence on potential negative impacts.
Conclusions:
Evidence for the use of mood-monitoring applications in youth is promising but limited due to a lack of high quality studies. Future work should explicate the effects of mobile mood-monitoring applications on effective self-regulation, clinical outcomes across disorders, and young people's engagement with mental health
services. Potential negative impacts in this population should also be investigated, as the adult literature suggests that application use could potentially increase negativity and depression symptoms
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