1,377 research outputs found

    A machine learning approach to photometric metallicities of giant stars

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    Despite the advances provided by large-scale photometric surveys, stellar features – such as metallicity – generally remain limited to spectroscopic observations often of bright, nearby low-extinction stars. To rectify this, we present a neural network approach for estimating the metallicities and distances of red giant stars with 8-band photometry and parallaxes from Gaia EDR3 and the 2MASS and WISE surveys. The algorithm accounts for uncertainties in the predictions arising from the range of possible outputs at each input and from the range of models compatible with the training set (through drop-out). A two-stage procedure is adopted where an initial network to estimate photoastrometric parallaxes is trained using a large sample of noisy parallax data from Gaia EDR3 and then a secondary network is trained using spectroscopic metallicities from the APOGEE and LAMOST surveys and an augmented feature space utilizing the first-stage parallax estimates. The algorithm produces metallicity predictions with an average uncertainty of ±0.19 dex\pm 0.19\, \mathrm{dex}. The methodology is applied to stars within the Galactic bar/bulge with particular focus on a sample of 1.69 million objects with Gaia radial velocities. We demonstrate the use and validity of our approach by inspecting both spatial and kinematic gradients with metallicity in the Galactic bar/bulge recovering previous results on the vertical metallicity gradient (−0.528 ± 0.002 dex kpc−1) and the vertex deviation of the bar (−21.29±2.74 deg-21.29\pm 2.74\, \mathrm{deg})

    Alcohol burden in low-income and middle-income countries

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    Child maltreatment in low- and middle-income countries overburdens health systems, compromises education, perpetuates gender inequalities and slows down development. Research suggests that parenting programmes are effective for the early prevention of child maltreatment. However, wide deployment in LMICs where violence towards children is high is yet to take place. In this overview article, we identify some critical challenges that LMICs currently face in ensuring the sustained implementation of parenting programmes for the early prevention of child maltreatment. The article is structured in three main sections: (1) a brief review of the effectiveness of parenting programmes for preventing child maltreatment; (2) a discussion of the critical challenges in LMICs for the widespread and sustained implementation of parenting programmes; and (3) we propose recommendations to promote effective implementation in these countries. We also suggest a series of steps to overcome these challenges, such as investing on capacity-building for sustainability

    Plans for the next GRAPE balloon flight

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    The Gamma RAy Polarimeter Experiment (GRAPE) was first flown on a 26-hour balloon flight in the fall of 2011. GRAPE consists of an array of Compton polarimeter modules (based on traditional scintillation technologies) designed to operate in the energy range from 50 keV up to 500 keV. The ultimate goal is to operate GRAPE in a wide FoV configuration for the study of gamma-ray bursts. For the first (demonstration) balloon flight, GRAPE was configured in a collimated mode to facilitate observations of known point sources. The Crab nebula/pulsar, the active Sun, and Cygnus X-1 were the primary targets for the first flight. Although the Crab was detected, the polarization sensitivity was worse than expected. This paper will review the plans for the next GRAPE balloon flight, which is scheduled to take place in the fall of 2014 from Ft. Sumner, NM. These plans involve several modifications designed to improve the polarization sensitivity, including an expansion of the array of polarimeter modules from 16 to 24 and improvements to the instrument shielding. Sensitivity estimates of the resulting instrument, based on GEANT4 simulations, will be presented

    Consistency of the Health of the Nation Outcome Scales (HoNOS) at inpatient-to-community transition

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    OBJECTIVES: The Health of the Nation Outcome Scales (HoNOS) are mandated outcome-measures in many mental-health jurisdictions. When HoNOS are used in different care settings, it is important to assess if setting specific bias exists. This article examines the consistency of HoNOS in a sample of psychiatric patients transitioned from acute inpatient care and community centres. SETTING: A regional mental health service with both acute and community facilities. PARTICIPANTS: 111 psychiatric patients were transferred from inpatient care to community care from 2012 to 2014. Their HoNOS scores were extracted from a clinical database; Each inpatient-discharge assessment was followed by a community-intake assessment, with the median period between assessments being 4 days (range 0-14). Assessor experience and professional background were recorded. PRIMARY AND SECONDARY OUTCOME MEASURES: The difference of HoNOS at inpatient-discharge and community-intake were assessed with Pearson correlation, Cohen\u27s κ and effect size. RESULTS: Inpatient-discharge HoNOS was on average lower than community-intake HoNOS. The average HoNOS was 8.05 at discharge (median 7, range 1-22), and 12.16 at intake (median 12, range 1-25), an average increase of 4.11 (SD 6.97). Pearson correlation between two total scores was 0.073 (95% CI -0.095 to 0.238) and Cohen\u27s κ was 0.02 (95% CI -0.02 to 0.06). Differences did not appear to depend on assessor experience or professional background. CONCLUSIONS: Systematic change in the HoNOS occurs at inpatient-to-community transition. Some caution should be exercised in making direct comparisons between inpatient HoNOS and community HoNOS scores

    Development and validation of the Cannabis Refusal Self-Efficacy Questionnaire (CRSEQ) in adult cannabis users in treatment

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    Background: There are few valid clinical assessment instruments for cannabis. Self-efficacy, or the ability of users to resist temptation, is a central feature of social cognitive theory. This study outlines the development and validation of the Cannabis Refusal Self-Efficacy Questionnaire (CRSEQ), which measures the situational confidence to refuse cannabis

    Craving mediates the effect of impulsivity on lapse-risk during alcohol use disorder treatment

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    Rash impulsiveness, the propensity for approach behaviour despite potential negative consequences, is associated with stronger alcohol craving in patients with Alcohol Use Disorder (AUD). This relationship is poorly understood and implications for treatment response are unexamined. This study explored the relationship between rash impulsiveness, craving, and treatment response among 304 outpatients enrolled in a 12-week abstinence-based Cognitive-Behavioural Therapy (CBT) program for AUD. Assessments were completed pre-and-post treatment, with craving and alcohol consumption monitored at each treatment session. Higher rash impulsiveness predicted more frequent craving over treatment (b = 0.95, 95% CI = 0.40, 1.50). Higher craving was associated with greater lapse-risk (b = 0.04, 95% CI = 0.03, 0.05), with the association between craving and lapse-risk increasing as treatment progressed (b = 0.01, 95% CI = 0.01, 0.02). Craving positively mediated the relationship between rash impulsiveness and lapse-risk (µ = 0.38, 95% CI = 0.10, 0.70). Contrary to hypotheses, the risk of lapse in response to craving was not moderated by rash-impulsiveness. These results suggest that AUD patients with a predisposition for rash impulsiveness are more vulnerable to alcohol craving, and subsequently, poorer treatment outcomes

    Integrating traditional bullying and cyberbullying: challenges of definition and measurement in adolescents - a review

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    The need for an integrated approach to studying bullying behaviors, both traditional and cyber, in adolescents is increasingly evident. The definitional criteria of bullying are well established in the traditional bullying literature and include (i) intention, (ii) repetition, and (iii) power imbalance. There is emerging evidence that these same criteria can be broadly applied to cyberbullying behaviors; however, important additional elements may include anonymity and publicity in a cyber-act. Fundamental to integrating traditional and cyberbullying are the measurement tools used to capture the extent and range of bullying behaviors. Self-report surveys are widely adopted as a method for measuring the prevalence of bullying victimization and perpetration. The current paper reviews the definitional and measurement issues relating to traditional and cyberbullying among school-aged youth. We conclude that both traditional and cyberbullying behaviors should be measured simultaneously. Operationalizing components of the definitional criteria in self-report surveys will result in more consistent and reliable measurement across all bullying behaviors

    Selective Control of Conductance Modes in Multi-terminal Josephson Junctions

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    The Andreev bound state spectra of multi-terminal Josephson junctions form an artificial band structure, which is predicted to host tunable topological phases under certain conditions. However, the number of conductance modes between the terminals of multi-terminal Josephson junction must be few in order for this spectrum to be experimentally accessible. In this work we employ a quantum point contact geometry in three-terminal Josephson devices. We demonstrate independent control of conductance modes between each pair of terminals and access to the single-mode regime coexistent with the presence of superconducting coupling. These results establish a full platform on which to realize tunable Andreev bound state spectra in multi-terminal Josephson junctions.Comment: 15 pages, 4 figure

    Gate-tunable Superconducting Diode Effect in a Three-terminal Josephson Device

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    The phenomenon of non-reciprocal critical current in a Josephson device, termed the Josephson diode effect, has garnered much recent interest. Realization of the diode effect requires inversion symmetry breaking, typically obtained by spin-orbit interactions. Here we report observation of the Josephson diode effect in a three-terminal Josephson device based upon an InAs quantum well two-dimensional electron gas proximitized by an epitaxial aluminum superconducting layer. We demonstrate that the diode efficiency in our devices can be tuned by a small out-of-plane magnetic field or by electrostatic gating. We show that the Josephson diode effect in these devices is a consequence of the artificial realization of a current-phase relation that contains higher harmonics. We also show nonlinear DC intermodulation and simultaneous two-signal rectification, enabled by the multi-terminal nature of the devices. Furthermore, we show that the diode effect is an inherent property of multi-terminal Josephson devices, establishing an immediately scalable approach by which potential applications of the Josephson diode effect can be realized, agnostic to the underlying material platform. These Josephson devices may also serve as gate-tunable building blocks in designing topologically protected qubits

    Enhanced mobility of ternary InGaAs quantum wells through digital alloying

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    High In content InGaAs quantum wells (In ≥ 75%) are potentially useful for topological quantum computing and spintronics applications. In high-mobility InGaAs quantum wells, alloy disorder scattering is a limiting factor. In this paper, we demonstrate that by growing the InGaAs quantum wells as a digital alloy, or a short period superlattice, we can reduce the alloy disorder scattering within the quantum well and increase the peak 2 K electron mobility to 545000 cm2/Vs, which is the highest reported mobility for high-In content InGaAs quantum wells to the best of the authors' knowledge. Our results demonstrate that the digital alloy approach can be used to increase the mobility of quantum wells in random alloy ternary materials
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