12,291 research outputs found

    Beyond the trial: A systematic review of real-world uptake and engagement with digital self-help interventions for depression, low mood, or anxiety

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    Background: Digital self-help interventions (including online or computerized programs and apps) for common mental health issues have been shown to be appealing, engaging, and efficacious in randomized controlled trials. They show potential for improving access to therapy and improving population mental health. However, their use in the real world, that is, as implemented (disseminated) outside of research settings, may differ from that reported in trials, and implementation data are seldom reported. Objective: We aimed to review peer-reviewed articles reporting user uptake and/or ongoing use, retention, or completion data (hereafter ‘usage data’ or, for brevity, ‘engagement’) from implemented pure self-help (unguided) digital interventions for depression, anxiety, or the enhancement of mood. Methods: We conducted a systematic search of the Scopus, Embase, MEDLINE, and PsychINFO databases for studies reporting user uptake and/or usage data from implemented digital self-help interventions for the treatment or prevention of depression or anxiety, or the enhancement of mood, from 2002 to 2017. Additionally, we screened the reference lists of included articles, citations of these articles, and the titles of articles published in Internet Interventions, Journal of Medical Internet Research (JMIR), and JMIR Mental Health since their inception. We extracted data indicating the number of registrations or downloads and usage of interventions. Results: After the removal of duplicates, 970 papers were identified, of which ten met the inclusion criteria. Hand-searching identified one additional article. The included articles reported on seven publically available interventions. There was little consistency in the measures reported. The number of registrants or downloads ranged widely, from eight to over 40,000 per month. From 21% to 88% of users engaged in at least minimal use (e.g. used the intervention at least once or completed one module or assessment), while 7–42% engaged in moderate use (completing between 40% and 60% of modular fixed-length programs or continuing to use apps after four weeks). Indications of completion or sustained use (completion of all modules or the last assessment or continuing to use apps after six weeks or more) varied from 0.5% to 28.6%. Conclusions: Available data suggest that uptake and engagement vary widely among the handful of implemented digital self-help apps and programs which have reported this, and that usage may vary from that reported in trials. Implementation data should be routinely gathered and reported to facilitate improved uptake and engagement, arguably among the major challenges in digital health

    Cosmic ray feedback in the FIRE simulations: constraining cosmic ray propagation with GeV gamma ray emission

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    We present the implementation and the first results of cosmic ray (CR) feedback in the Feedback In Realistic Environments (FIRE) simulations. We investigate CR feedback in non-cosmological simulations of dwarf, sub-L⋆L\star starburst, and L⋆L\star galaxies with different propagation models, including advection, isotropic and anisotropic diffusion, and streaming along field lines with different transport coefficients. We simulate CR diffusion and streaming simultaneously in galaxies with high resolution, using a two moment method. We forward-model and compare to observations of γ\gamma-ray emission from nearby and starburst galaxies. We reproduce the γ\gamma-ray observations of dwarf and L⋆L\star galaxies with constant isotropic diffusion coefficient κ∼3×1029 cm2 s−1\kappa \sim 3\times 10^{29}\,{\rm cm^{2}\,s^{-1}}. Advection-only and streaming-only models produce order-of-magnitude too large γ\gamma-ray luminosities in dwarf and L⋆L\star galaxies. We show that in models that match the γ\gamma-ray observations, most CRs escape low-gas-density galaxies (e.g.\ dwarfs) before significant collisional losses, while starburst galaxies are CR proton calorimeters. While adiabatic losses can be significant, they occur only after CRs escape galaxies, so they are only of secondary importance for γ\gamma-ray emissivities. Models where CRs are ``trapped'' in the star-forming disk have lower star formation efficiency, but these models are ruled out by γ\gamma-ray observations. For models with constant κ\kappa that match the γ\gamma-ray observations, CRs form extended halos with scale heights of several kpc to several tens of kpc.Comment: 31 pages, 26 figures, accepted for publication in MNRA

    Calibration of the Ames Anechoic Facility. Phase 1: Short range plan

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    A calibration was made of the acoustic and aerodynamic characteristics of a small, open-jet wind tunnel in an anechoic room. The jet nozzle was 102 mm diameter and was operated subsonically. The anechoic-room dimensions were 7.6 m by 5.5 m by 3.4 m high (wedge tip to wedge tip). Noise contours in the chamber were determined by various jet speeds and exhaust collector positions. The optimum nozzle/collector separation from an acoustic standpoint was 2.1 m. Jet velocity profiles and turbulence levels were measured using pressure probes and hot wires. The jet was found to be symmetric, with no unusual characteristics. The turbulence measurements were hampered by oil mist contamination of the airflow

    Defect Detection in Bonded Structures Using the Reverberant Wavefield

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    With the increasing use of adhesives in the automotive, aerospace, and manufacturing industries, there is a growing interest in developing nondestructive methods for locating defects in adhesive bonds. While conventional techniques which utilize ultrasonic waves and Lamb waves are likely candidates for obtaining high resolution images of defects, these methods may not be practical for assembly line applications where the time required to scan the bonds and the access to the bonds are often limited. The objective of this work is to develop an approach for detecting defects in bonds that requires only a limited number of measurements of the reverberant acoustic wavefield (i.e., waves that are multiply scattered off the boundaries of the structure) made over a band of frequencies

    The origin of ultra diffuse galaxies: stellar feedback and quenching

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    We test if the cosmological zoom-in simulations of isolated galaxies from the FIRE project reproduce the properties of ultra diffuse galaxies. We show that stellar feedback-generated outflows that dynamically heat galactic stars, together with a passively aging stellar population after imposed quenching (from e.g. infall into a galaxy cluster), naturally reproduce the observed population of red UDGs, without the need for high spin halos or dynamical influence from their host cluster. We reproduce the range of surface brightness, radius and absolute magnitude of the observed z=0 red UDGs by quenching simulated galaxies at a range of different times. They represent a mostly uniform population of dark matter-dominated galaxies with M_star ~1e8 Msun, low metallicity and a broad range of ages. The most massive simulated UDGs require earliest quenching and are therefore the oldest. Our simulations provide a good match to the central enclosed masses and the velocity dispersions of the observed UDGs (20-50 km/s). The enclosed masses of the simulated UDGs remain largely fixed across a broad range of quenching times because the central regions of their dark matter halos complete their growth early. A typical UDG forms in a dwarf halo mass range of Mh~4e10-1e11 Msun. The most massive red UDG in our sample requires quenching at z~3 when its halo reached Mh ~ 1e11 Msun. If it, instead, continues growing in the field, by z=0 its halo mass reaches > 5e11 Msun, comparable to the halo of an L* galaxy. If our simulated dwarfs are not quenched, they evolve into bluer low-surface brightness galaxies with mass-to-light ratios similar to observed field dwarfs. While our simulation sample covers a limited range of formation histories and halo masses, we predict that UDG is a common, and perhaps even dominant, galaxy type around Ms~1e8 Msun, both in the field and in clusters.Comment: 20 pages, 13 figures; match the MNRAS accepted versio

    Breathing FIRE: How Stellar Feedback Drives Radial Migration, Rapid Size Fluctuations, and Population Gradients in Low-Mass Galaxies

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    We examine the effects of stellar feedback and bursty star formation on low-mass galaxies (Mstar=2×106−5×1010M⊙M_{\rm star}=2\times10^6-5\times10^{10}{\rm M_{\odot}}) using the FIRE (Feedback in Realistic Environments) simulations. While previous studies emphasized the impact of feedback on dark matter profiles, we investigate the impact on the stellar component: kinematics, radial migration, size evolution, and population gradients. Feedback-driven outflows/inflows drive significant radial stellar migration over both short and long timescales via two processes: (1) outflowing/infalling gas can remain star-forming, producing young stars that migrate ∼1 kpc\sim1{\rm\,kpc} within their first 100 Myr100 {\rm\,Myr}, and (2) gas outflows/inflows drive strong fluctuations in the global potential, transferring energy to all stars. These processes produce several dramatic effects. First, galaxies' effective radii can fluctuate by factors of >2>2 over ∼200 Myr\sim200 {\rm\,Myr}, and these rapid size fluctuations can account for much of the observed scatter in radius at fixed Mstar.M_{\rm star}. Second, the cumulative effects of many outflow/infall episodes steadily heat stellar orbits, causing old stars to migrate outward most strongly. This age-dependent radial migration mixes---and even inverts---intrinsic age and metallicity gradients. Thus, the galactic-archaeology approach of calculating radial star-formation histories from stellar populations at z=0z=0 can be severely biased. These effects are strongest at Mstar≈107−9.6M⊙M_{\rm star}\approx10^{7-9.6}{\rm M_{\odot}}, the same regime where feedback most efficiently cores galaxies. Thus, detailed measurements of stellar kinematics in low-mass galaxies can strongly constrain feedback models and test baryonic solutions to small-scale problems in Λ\LambdaCDM.Comment: Accepted to ApJ (820, 131) with minor revisions from v1. Figure 4 now includes dark matter. Main results in Figures 7 and 1

    On the deuterium abundance and the importance of stellar mass loss in the interstellar and intergalactic medium

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    We quantify the gas-phase abundance of deuterium and fractional contribution of stellar mass loss to the gas in cosmological zoom-in simulations from the Feedback In Realistic Environments project. At low metallicity, our simulations confirm that the deuterium abundance is very close to the primordial value. The chemical evolution of the deuterium abundance that we derive here agrees quantitatively with analytical chemical evolution models. We furthermore find that the relation between the deuterium and oxygen abundance exhibits very little scatter. We compare our simulations to existing high-redshift observations in order to determine a primordial deuterium fraction of 2.549 +/- 0.033 x 10^-5 and stress that future observations at higher metallicity can also be used to constrain this value. At fixed metallicity, the deuterium fraction decreases slightly with decreasing redshift, due to the increased importance of mass loss from intermediate-mass stars. We find that the evolution of the average deuterium fraction in a galaxy correlates with its star formation history. Our simulations are consistent with observations of the Milky Way's interstellar medium: the deuterium fraction at the solar circle is 85-92 per cent of the primordial deuterium fraction. We use our simulations to make predictions for future observations. In particular, the deuterium abundance is lower at smaller galactocentric radii and in higher mass galaxies, showing that stellar mass loss is more important for fuelling star formation in these regimes (and can even dominate). Gas accreting onto galaxies has a deuterium fraction above that of the galaxies' interstellar medium, but below the primordial fraction, because it is a mix of gas accreting from the intergalactic medium and gas previously ejected or stripped from galaxies.Comment: Accepted for publication in MNRAS. Revised version: expanded discussion and added Figure 2 (residual dependence on iron abundance
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