2,207 research outputs found

    Thresholds for safer alcohol use might need lowering

    Get PDF

    The Age of Onset of Alcohol Use Disorders

    Full text link
    Individuals with an alcohol use disorder account for around half of all the alcohol-related harm in developed societies and contribute to around 4% of global disease burden. In the USA, around 18% of men and 10% of women met DSM-5 criteria for alcohol use disorder in the past year. This chapter summarizes what we know about cultural, environmental and genetic factors associated with age of alcohol onset patterns and what remains to be understood. It examines factors associated with alcohol use initiation and the relationship between onset, severity of alcohol use disorders and individual functioning. It assesses patterns of early and late alcohol use as possible clinical markers for more effective treatment and prevention approaches. Evidence on the effectiveness of public policies to delay age of onset is reviewed. The existing evidence is considered in light of methodological challenges in age of onset research, particularly in establishing a possible causal role for early onset of drinking in risk of developing alcohol use disorders

    A machine learning approach to photometric metallicities of giant stars

    Get PDF
    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})

    Maintenance Actions to Address Fatigue Cracking in Steel Bridge Structures: Proposed Guidelines and Commentary

    Get PDF
    This document provides guidelines for the maintenance actions to address fatigue cracking and details at risk of constraint-induced fracture (CIF) in steel bridges. It is a synthesis of best practices from published literature, project reports, past and ongoing research projects, as well as input from industry professionals gathered through a web-based survey. Intended to be a very practical reference text, it is written with everyone in mind from a maintenance contractor to an asset manager and design engineer, providing detailed descriptions of the driving causes of fatigue cracking and CIF in steel bridges and accepted methods for repair or retrofit. A number of case studies are discussed giving context for the different detail susceptibilities and utilizing a mixture of real-world and rendered images to illustrate the problems and solutions. For each case, a suggested sequence of steps is also provided as a ‘‘how-to.’

    Gold-alkynyls in catalysis : Alkyne activation, gold cumulenes and nuclearity

    Get PDF
    The use of cationic gold(i) species in the activation of substrates containing CC bonds has become a valuable tool for synthetic chemists. Despite the seemingly simple label of 'alkyne activation', numerous patterns of reactivity and product structure are observed in systems employing related substrates and catalysts. The complications of mechanistic determination are compounded as the number of implicated gold(i) centres involved in catalysis increases and debate about the bonding in proposed intermediates clouds the number and importance of potential reaction pathways. This perspective aims to illustrate some of the principles underpinning gold-alkynyl interactions whilst highlighting some of the contentious areas in the field and offering some insight into other, often ignored, mechanistic possibilities based on recent findings

    Synthesis of neutral nickel catalysts for ethylene polymerization – the influence of ligand size on catalyst stability

    Get PDF
    A facile synthesis of nickel salicylaldimine complexes with labile dissociating ligands is described. In addition to producing highly active ethylene polymerization catalysts, important insights into the effect of ligand size on catalyst stability and information on the mechanism of polymerization are provided

    The outlet design of flat fan nozzle varies the application time of day effect on nicosulfuron activity

    Get PDF
    Saabunud / Received 15.09.2021 ; Aktsepteeritud / Accepted 22.12.2021 ; Avaldatud veebis / Published online 23.12.2021 ; Vastutav autor / Corresponding author: Akbar Aliverdi [email protected] two container-grown species, johnsongrass and velvet-leaf, nicosulfuron was sprayed with the Anti-Drift Single, Dual, and Triplet Flat-Fan nozzles (AD/S, AD/D, AD/T nozzles, respectively) at 05:00 to 21:00, with a two-hour interval. At 5:00 to 11:00, nicosulfuron activity on both species was greatest with the AD/T followed by the AD/D and finally, the AD/S nozzle. At 15:00 to 19:00, however, nicosulfuron activity on johnsongrass was greatest with the AD/D, followed by the AD/T and finally, the AD/S nozzle, and nicosulfuron activity on velvetleaf was greatest with the AD/D followed by the AD/S and the AD/T nozzle had the lowest control. Nicosulfuron applied with the AD/T nozzle in the early morning caused the highest desiccation (70%) in both species. The best time to apply nicosulfuron was in the early morning. However, velvetleaf undergoes foliar nyctinasty depending on daylight, which made effective control achieved by only the AD/D and AD/T nozzles

    Plans for the first balloon flight of the gamma-ray polarimeter experiment (GRAPE)

    Get PDF
    We have developed a design for a hard X-ray polarimeter operating in the energy range from 50 to 500 keV. This modular design, known as GRAPE (Gamma-Ray Polarimeter Experiment), has been successfully demonstrated in the lab using partially polarized gamma-ray sources and using fully polarized photon beams at Argonne National Laboratory. In June of 2007, a GRAPE engineering model, consisting of a single detector module, was flown on a high altitude balloon flight to further demonstrate the design and to collect background data. We are currently preparing a much larger balloon payload for a flight in the fall of 2011. Using a large (16-element) array of detector modules, this payload is being designed to search for polarization from known point sources of radiation, namely the Crab and Cygnus X-1. This first flight will not only provide a scientific demonstration of the GRAPE design (by measuring polarization from the Crab nebula), it will also lay the foundation for subsequent long duration balloon flights that will be designed for studying polarization from gamma-ray bursts and solar flares. Here we shall present data from calibration of the first flight module detectors, review the latest payload design and update the predicted polarization sensitivity for both the initial continental US balloon flight and the subsequent long-duration balloon flights

    GRAPE: a balloon-borne gamma-ray polarimeter

    Get PDF
    The Gamma-RAy Polarimeter Experiment (GRAPE) is a concept for an astronomical hard X-ray Compton polarimeter operating in the 50 - 500 keV energy band. The instrument has been optimized for wide-field polarization measurements of transient outbursts from energetic astrophysical objects such as gamma-ray bursts and solar flares. The GRAPE instrument is composed of identical modules, each of which consists of an array of scintillator elements read out by a multi-anode photomultiplier tube (MAPMT). Incident photons Compton scatter in plastic scintillator elements and are subsequently absorbed in inorganic scintillator elements; a net polarization signal is revealed by a characteristic asymmetry in the azimuthal scattering angles. We have constructed a prototype GRAPE module that has been calibrated at a polarized hard X-ray beam and flown on an engineering balloon test flight. A full-scale scientific balloon payload, consisting of up to 36 modules, is currently under development. The first flight, a one-day flight scheduled for 2011, will verify the expected scientific performance with a pointed observation of the Crab Nebula. We will then propose long-duration balloon flights to observe gamma-ray bursts and solar flares
    • …
    corecore