443 research outputs found
First Results From the Large Binocular Telescope: Deep Photometry of New dSphs
This contribution describes photometry for two Galactic dSphs obtained with
the Large Binocular Telescope to a magnitude of ~25.5. Using the Large
Binocular Camera, a purpose-built wide-field imager for the LBT, we have
examined the structure and star formation histories of two newly-discovered
Local Group members, the Hercules dSph and the Leo T dSph/dIrr system. We have
constructed a structural map for the Hercules system using three-filter
photometry to V ~ 25.5. This is the first deep photometry for this system, and
it indicates that Hercules is unusually elongated, possibly indicating
distortion due to the Galactic tidal field. We have also derived the first star
formation history for the Leo T system, and find that its oldest population of
stars (age ~ 13 Gyr) were relatively metal-rich, with [Fe/H] ~ -1.5.Comment: Four pages, two figures. To appear in the proceedings of "Galaxies in
the Local Volume", Astrophysics and Space Science, editors B. Koribalski and
H. Jerje
Resolving Stellar Populations outside the Local Group: MAD observations of UKS2323-326
We present a study aimed at deriving constraints on star formation at
intermediate ages from the evolved stellar populations in the dwarf irregular
galaxy UKS2323-326. These observations were also intended to demonstrate the
scientific capabilities of the multi-conjugated adaptive optics demonstrator
(MAD) implemented at the ESO Very Large Telescope as a test-bench of adaptive
optics (AO) techniques. We perform accurate, deep photometry of the field using
J and Ks band AO images of the central region of the galaxy. The near-infrared
(IR) colour-magnitude diagrams clearly show the sequences of asymptotic giant
branch (AGB) stars, red supergiants, and red giant branch (RGB) stars down to
~1 mag below the RGB tip. Optical-near-IR diagrams, obtained by combining our
data with Hubble Space Telescope observations, provide the best separation of
stars in the various evolutionary stages. The counts of AGB stars brighter than
the RGB tip allow us to estimate the star formation at intermediate ages.
Assuming a Salpeter initial mass function, we find that the star formation
episode at intermediate ages produced ~6x10^5 M_sun of stars in the observed
region.Comment: 4 pages, 4 figures, Accepted for publication in A&A Letter
Ground-based CCD astrometry with wide field imagers. IV. An improved Geometric Distortion Correction for the Blue prime-focus Camera at the LBT
High precision astrometry requires an accurate geometric distortion solution.
In this work, we present an average correction for the Blue Camera of the Large
Binocular Telescope which enables a relative astrometric precision of ~15 mas
for the B_Bessel and V_Bessel broad-band filters. The result of this effort is
used in two companion papers: the first to measure the absolute proper motion
of the open cluster M67 with respect to the background galaxies; the second to
decontaminate the color-magnitude diagram of M67 from field objects, enabling
the study of the end of its white dwarf cooling sequence. Many other
applications might find this distortion correction useful.Comment: 13 pages, 11 figures, 4 tables. accepted for publication on Astronomy
and Astrophysic
Training Package for Emergency Medical Teams Deployed to Disaster Stricken Areas: Has 'TEAMS' Achieved its Goals?
In spite of their good intentions, Emergency Medical Teams (EMTs) were relatively disorganized for many years. To enhance the efficient provision of EMT's field team work, the Training for Emergency Medical Teams and European Medical Corps (TEAMS) project was established. The purpose of this study was to assess the effectiveness and quality of the TEAMS training package in 2 pilot training programs in Germany and Turkey. A total of 19 German and 29 Turkish participants completed the TEAMS training package. Participants were asked to complete a set of questionnaires designed to assess self-efficacy, team work, and quality of training. The results suggest an improvement for both teams' self-efficacy and team work. The self-efficacy scale improved from 3.912 (± 0.655 SD) prior to training to 4.580 (± 0.369 SD) after training (out of 5). Team work improved from 3.085 (± 0.591 SD) to 3.556 (± 0.339 SD) (out of 4). The overall mean score of the quality of the training scale was 4.443 (± 0.671 SD) (out of 5). In conclusion, The TEAMS Training Package for Emergency Medical Teams has been demonstrated to be effective in promoting EMT team work capacities, and it is considered by its users to be a useful and appropriate tool for addressing their perceived needs
MCAO near-IR photometry of the Globular Cluster NGC 6388: MAD observations in crowded fields
Deep photometry of crowded fields, such as Galactic Globular Clusters, is
severely limited by the actual resolution of ground-based telescopes. On the
other hand, the Hubble Space Telescope does not provide the near-infrared (NIR)
filters needed to allow large color baselines. In this work we aim at
demonstrating how ground based observations can reach the required resolution
when using Multi-Conjugated Adaptive Optic (MCAO) devices in the NIR, such as
the experimental infrared camera (MAD) available on the VLT. This is
particularly important since these corrections are planned to be available on
all ground--based telescopes in the near future. We do this by combining the
infrared photometry obtained by MAD/VLT with ACS/HST optical photometry of our
scientific target, the bulge globular cluster NGC 6388, in which we imaged two
fields. In particular, we constructed color-magnitude diagrams with an
extremely wide color baseline in order to investigate the presence of multiple
stellar populations in this cluster. From the analysis of the external field,
observed with better seeing conditions, we derived the deepest optical-NIR CMD
of NGC 6388 to date. The high-precision photometry reveals that two distinct
sub-giant branches are clearly present in this cluster. We also use the CMD
from the central region to estimate the distance ((m-M)=15.33) and the
reddening (E(B-V)=0.38) for this cluster. We estimate the age to be ~11.5+/-
1.5 Gyr. The large relative-age error reflects the bimodal distribution of the
SGB stars. This study clearly demonstrates how MCAO correction in the NIR bands
implemented on ground based telescopes can complement the high-resolution
optical data from HST.Comment: 9 pages, 10 figures. Accepted for publication on A. &
Negative consequences of conflict-related sexual violence on survivors: a systematic review of qualitative evidence
BackgroundConflicts exacerbate dynamics of power and inequalities through violence normalization, which acts as a facilitator for conflict-related sexual violence. Literature addressing its negative outcomes on survivors is scant. The aim of this systematic review was to analyze the qualitative evidence reported in scientific literature and focusing on the negative consequences of conflict-related sexual violence on victims' physical, psychological, and social dimensions of health in a gender-inclusive and disaggregated form.MethodsA literature search was conducted on January 13, 2023 on Pubmed, Scopus, and PsychArticles. The search strings combined two blocks of terms related to sexual violence and conflict. A time filter was applied, limiting the search to studies published in the last ten years. Information regarding the main characteristics and design of the study, survivors and their experience, and about conflict-related sexual violence was collected. The negative consequences of conflict-related sexual violence on the physical, psychological, and social dimension of victims were extracted according to the Biopsychosocial model of health. The review followed the Joanna Briggs Institute methodology for systematic reviews and relied on the Preferred Reporting Items for Systematic reviews and Meta-Analyses.ResultsAfter full text review, 23 articles met the inclusion criteria, with 18 of them reporting negative repercussions on physical health, all of them highlighting adverse psychological outcomes, and 21 disclosing unfavorable social consequences. The negative outcomes described in multiple studies were sexual and reproductive health issues, the most mentioned being pregnancy, manifestations of symptoms attributable to post-traumatic stress disorder, and stigma. A number of barriers to access to care were presented as emerging findings.ConclusionsThis review provided an analysis of the negative consequences of conflict-related sexual violence on survivors, thus highlighting the importance of qualitative evidence in understanding these outcomes and addressing barriers to access to care. Conflict-related sexual violence is a sexual and reproductive health issue. Sexuality education is needed at individual, community, and provider level, challenging gender norms and roles and encompassing gender-based violence. Gender-inclusive protocols and services need to be implemented to address the specific needs of all victims. Governments should advocate for SRHRs and translate health policies into services targeting survivors of CRSV
Virtual reality and live scenario simulation: options for training medical students in mass casualty incident triage
Introduction
Multicasualty triage is the process of establishing the priority of care among casualties in disaster management. Recent mass casualty incidents (MCI) revealed that health personnel are unfamiliar with the triage protocols. The objective of this study is to compare the relative impact of two simulation-based methods for training medical students in mass casualty triage using the Simple Triage and Rapid Treatment (START) algorithm.
Methods
A prospective randomized controlled longitudinal study. Medical students enrolled in the emergency medicine course were randomized into two groups (A and B). On day 1, group A students were exposed to a virtual reality (VR) scenario and group B students were exposed to a live scenario (LS), both exercises aiming at triaging 10 victims in a limited period of time (30 seconds/victim). On day 2 all students attended a 2-hour lecture about medical disaster management and START. On day 3 group A and B students were exposed to a LS and to a VR scenario respectively. The vital signs and clinical condition of the 10 victims were identical in the two scenarios. Ability of the groups to manage a simulated triage scenario was then compared (times and triage accuracy).
Results
Groups A and B were composed of 25 and 28 students respectively. During day 1 group A LS triage accuracy was 58%, while the average time to assess all patients was 4 minutes 28 seconds. The group B VR scenario triage accuracy was 52%, while the average time to complete the assessment was 5 minutes 18 seconds. During day 3 the triage accuracy for group A VR simulation was 92%, while the average time was 3 minutes 53 seconds. Group B triage accuracy during the LS was 84%, with an average time of 3 minutes 25 seconds. Triage scores improved significantly during day 3 (P < 0.001) in the two groups. The time to complete each scenario decreased significantly from day 1 to day 3.
Conclusions
The study demonstrates that the training course generates significant improvement in triage accuracy and speed. It also reveals that VR simulation compared to live exercises has equivalent results in prompting critical decisions in mass casualty drills. In the beginning the average time to complete the VR scenario was higher than the LS. This could be due to the fact that on day 1 very detailed VR victims created a higher challenge for untaught students. However, the higher triage accuracy recorded at the end of day 3 in VR could be explained by a lower stress level compared to the LS, which could be creating a more stressful environment in taught students
Laser Guide Stars for Extremely Large Telescopes: Efficient Shack-Hartmann Wavefront Sensor Design using Weighted center-of-gravity algorithm
Over the last few years increasing consideration has been given to the study
of Laser Guide Stars (LGS) for the measurement of the disturbance introduced by
the atmosphere in optical and near-infrared astronomical observations from the
ground. A possible method for the generation of a LGS is the excitation of the
Sodium layer in the upper atmosphere at approximately 90 km of altitude. Since
the Sodium layer is approximately 10 km thick, the artificial reference source
looks elongated, especially when observed from the edge of a large aperture.
The spot elongation strongly limits the performance of the most common
wavefront sensors. The centroiding accuracy in a Shack-Hartmann wavefront
sensor, for instance, decreases proportionally to the elongation (in a photon
noise dominated regime). To compensate for this effect a straightforward
solution is to increase the laser power, i.e. to increase the number of
detected photons per subaperture. The scope of the work presented in this paper
is twofold: an analysis of the performance of the Weighted Center of Gravity
algorithm for centroiding with elongated spots and the determination of the
required number of photons to achieve a certain average wavefront error over
the telescope aperture.Comment: 10 pages, 14 figure
LBT Discovery of a Yellow Supergiant Eclipsing Binary in the Dwarf Galaxy Holmberg IX
In a variability survey of M81 using the Large Binocular Telescope we have
discovered a peculiar eclipsing binary (MV ~ -7.1) in the field of the dwarf
galaxy Holmberg IX. It has a period of 272 days and the light curve is well-fit
by an overcontact model in which both stars are overflowing their Roche lobes.
It is composed by two yellow supergiants (V-I ~ 1 mag, T_eff = 4800 K), rather
than the far more common red or blue supergiants. Such systems must be rare.
While we failed to find any similar systems in the literature, we did, however
note a second example. The SMC F0 supergiant R47 is a bright (MV ~ -7.5)
periodic variable whose All Sky Automated Survey (ASAS) light curve is well-fit
as a contact binary with a 181 day period. We propose that these systems are
the progenitors of supernovae like SN 2004et and SN 2006ov, which appeared to
have yellow progenitors. The binary interactions (mass transfer, mass loss)
limit the size of the supergiant to give it a higher surface temperature than
an isolated star at the same core evolutionary stage. We also discuss the
possibility of this variable being a long-period Cepheid.Comment: ApJ Letters, accepted, 15 pages, 4 figures, 1 table, and 1 photometry
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