446 research outputs found
Prevalence and associated harm of engagement in self-Asphyxial behaviours ('choking game') in young people:A systematic review
Prevalence and associated harm of engagement in self-Asphyxial behaviours ('choking game') in young people:A systematic review
OBJECTIVE: To assess the prevalence of engagement in self-asphyxial (risk-taking) behaviour (SAB) (‘choking game’) and associated morbidity and mortality in children and young people up to age 20. DESIGN: Systematic literature review. SEARCH STRATEGY: Electronic database search of MEDLINE, Embase, PsycINFO, CINAHL, PubMed, Web of Science Core Collection, BIOSIS citation index and the Cochrane register with no language or date limits applied. References of key papers were reviewed, and experts were contacted to identify additional relevant papers. ELIGIBILITY CRITERIA: Systematic reviews, cross-sectional, cohort and case–control studies, and case reports examining SAB with regard to individuals aged 0–20 years, without explicitly stated autoerotic, suicidal or self-harm intentions were included. RESULTS: Thirty-six relevant studies were identified, and SAB was reported in 10 countries. In North America, France and Colombia, awareness of SAB ranged from 36% to 91% across studies/settings, and the median lifetime prevalence of engagement in SAB was 7.4%. Six studies identified the potential for SAB to be associated with engagement in other risk behaviours. Ninety-nine fatal cases were reported. Of the 24 cases described in detail, most occurred when individuals engaged in SAB alone and used a ligature. CONCLUSIONS: The current evidence on SAB among young people is limited, and stems predominantly from North America and France. Awareness of SAB among young people is high, and engagement varies by setting. Further research is needed to understand the level of risk and harm associated with SAB, and to determine the appropriate public health response
Cerebellar Functional Parcellation Using Sparse Dictionary Learning Clustering
10.3389/fnins.2016.00188Frontiers in neuroscience10188GUSTO (Growing up towards Healthy Outcomes
Exomoon simulations
We introduce and describe our newly developed code that simulates light
curves and radial velocity curves for arbitrary transiting exoplanets with a
satellite. The most important feature of the program is the calculation of
radial velocity curves and the Rossiter-McLaughlin effect in such systems. We
discuss the possibilities for detecting the exomoons taking the abilities of
Extremely Large Telescopes into account. We show that satellites may be
detected also by their RM effect in the future, probably using less accurate
measurements than promised by the current instrumental developments. Thus, RM
effect will be an important observational tool in the exploration of exomoons.Comment: 5 pages, 2 figures with 9 figure panels, accepted by EM&
Detection of transit timing variations in excess of one hour in the Kepler multi-planet candidate system KOI 806 with the GTC
We report the detection of transit timing variations (TTVs) well in excess of
one hour in the Kepler multi-planet candidate system KOI 806. This system
exhibits transits consistent with three separate planets -- a Super-Earth, a
Jupiter, and a Saturn -- lying very nearly in a 1:2:5 resonance, respectively.
We used the Kepler public data archive and observations with the Gran
Telescopio de Canarias to compile the necessary photometry. For the largest
candidate planet (KOI 806.02) in this system, we detected a large transit
timing variation of -103.56.9 minutes against previously published
ephemeris. We did not obtain a strong detection of a transit color signature
consistent with a planet-sized object; however, we did not detect a color
difference in transit depth, either. The large TTV is consistent with
theoretical predictions that exoplanets in resonance can produce large transit
timing variations, particularly if the orbits are eccentric. The presence of
large TTVs among the bodies in this systems indicates that KOI806 is very
likely to be a planetary system. This is supported by the lack of a strong
color dependence in the transit depth, which would suggest a blended eclipsing
binary.Comment: 9 pages, 4 figures, accepted into A&A Letter
A Transiting Jupiter Analog
Decadal-long radial velocity surveys have recently started to discover
analogs to the most influential planet of our solar system, Jupiter. Detecting
and characterizing these worlds is expected to shape our understanding of our
uniqueness in the cosmos. Despite the great successes of recent transit
surveys, Jupiter analogs represent a terra incognita, owing to the strong
intrinsic bias of this method against long orbital periods. We here report on
the first validated transiting Jupiter analog, Kepler-167e (KOI-490.02),
discovered using Kepler archival photometry orbiting the K4-dwarf KIC-3239945.
With a radius of , a low orbital eccentricity
() and an equilibrium temperature of K,
Kepler-167e bears many of the basic hallmarks of Jupiter. Kepler-167e is
accompanied by three Super-Earths on compact orbits, which we also validate,
leaving a large cavity of transiting worlds around the habitable-zone. With two
transits and continuous photometric coverage, we are able to uniquely and
precisely measure the orbital period of this post snow-line planet
( d), paving the way for follow-up of this mag
target.Comment: 14 pages, 10 figures. Accepted to ApJ. Posteriors available at
https://github.com/CoolWorlds/Kepler-167-Posterior
Bayesian Methods for Exoplanet Science
Exoplanet research is carried out at the limits of the capabilities of
current telescopes and instruments. The studied signals are weak, and often
embedded in complex systematics from instrumental, telluric, and astrophysical
sources. Combining repeated observations of periodic events, simultaneous
observations with multiple telescopes, different observation techniques, and
existing information from theory and prior research can help to disentangle the
systematics from the planetary signals, and offers synergistic advantages over
analysing observations separately. Bayesian inference provides a
self-consistent statistical framework that addresses both the necessity for
complex systematics models, and the need to combine prior information and
heterogeneous observations. This chapter offers a brief introduction to
Bayesian inference in the context of exoplanet research, with focus on time
series analysis, and finishes with an overview of a set of freely available
programming libraries.Comment: Invited revie
A consistent analysis of three years of ground- and space-based photometry of TrES-2
The G0V dwarf TrES-2A, which is transited by a hot Jupiter, is one of the
main short-cadence targets of the Kepler telescope and, therefore, among the
photometrically best-studied planetary systems known today. Given the
near-grazing geometry of the planetary orbit, TrES-2 offers an outstanding
opportunity to search for changes in its orbital geometry. Our study focuses on
the secular change in orbital inclination reported in previous studies. We
present a joint analysis of the first four quarters of Kepler photometry
together with the publicly available ground-based data obtained since the
discovery of TrES-2b in 2006. We use a common approach based on the latest
information regarding the visual companion of TrES-2A and stellar limb
darkening to further refine the orbital parameters. We find that the Kepler
observations rule out a secular inclination change of previously claimed order
as well as variations of the transit timing, however, they also show slight
indication for further variability in the inclination which remains marginally
significant
A novel method for identifying exoplanetary rings
ABSTRACT: The discovery of rings around extrasolar planets (“exorings”) is one of the next breakthroughs in exoplanetary research. Previous studies have explored the feasibility of detecting exorings with present and futuren photometric sensitivities by seeking anomalous deviations in the residuals of a standard transit light curve fit, at the level of ~-100 ppm for Kronian rings. In this work, we explore two much larger observational consequences of exorings: (1) the significant increase in transit depth that may lead to the misclassification of ringed planetary candidates as false-positives and/or the underestimation of planetary density; and (2) the so-called “photo-ring” effect, a new asterodensity profiling effect, revealed by a comparison of the light curve derived stellar density to that measured with independent methods (e.g., asteroseismology). While these methods do not provide an unambiguous detection of exorings, we show that the large amplitude of these effects, combined with their relatively simple analytic description, makes them highly suited to large-scale surveys to identify candidate ringed planets worthy of more detailed investigation. Moreover, these methods lend themselves to ensemble analyses seeking to uncover evidence of a population of ringed planets. We describe the method in detail, develop the basic underlying formalism, and test it in the parameter space of rings and transit configuration. We discuss the prospects of using this method for the first systematic search of exoplanetary rings in the Kepler database and provide a basic computational code for implementing it
HAT-P-26b: A Low-Density Neptune-Mass Planet Transiting a K Star
We report the discovery of HAT-P-26b, a transiting extrasolar planet orbiting
the moderately bright V=11.744 K1 dwarf star GSC 0320-01027, with a period P =
4.234516 +- 0.000015 d, transit epoch Tc = 2455304.65122 +- 0.00035 (BJD), and
transit duration 0.1023 +- 0.0010 d. The host star has a mass of 0.82 +- 0.03
Msun, radius of 0.79 + 0.10 - 0.04 Rsun, effective temperature 5079 +- 88 K,
and metallicity [Fe/H] = -0.04 +- 0.08. The planetary companion has a mass of
0.059 +- 0.007 MJ, and radius of 0.565 + 0.072 - 0.032 RJ yielding a mean
density of 0.40 +- 0.10 g cm-3. HAT-P-26b is the fourth Neptune-mass transiting
planet discovered to date. It has a mass that is comparable to those of Neptune
and Uranus, and slightly smaller than those of the other transiting
Super-Neptunes, but a radius that is ~65% larger than those of Neptune and
Uranus, and also larger than those of the other transiting Super-Neptunes.
HAT-P-26b is consistent with theoretical models of an irradiated Neptune-mass
planet with a 10 Mearth heavy element core that comprises >~ 50% of its mass
with the remainder contained in a significant hydrogen-helium envelope, though
the exact composition is uncertain as there are significant differences between
various theoretical models at the Neptune-mass regime. The equatorial
declination of the star makes it easily accessible to both Northern and
Southern ground-based facilities for follow-up observations.Comment: 16 pages, 9 figures, 5 tables, submitted to Ap
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