44 research outputs found

    Observational Constraints on the Catastrophic Disruption Rate of Small Main Belt Asteroids

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    We have calculated 90% confidence limits on the steady-state rate of catastrophic disruptions of main belt asteroids in terms of the absolute magnitude at which one catastrophic disruption occurs per year (HCL) as a function of the post-disruption increase in brightness (delta m) and subsequent brightness decay rate (tau). The confidence limits were calculated using the brightest unknown main belt asteroid (V = 18.5) detected with the Pan-STARRS1 (Pan-STARRS1) telescope. We measured the Pan-STARRS1's catastrophic disruption detection efficiency over a 453-day interval using the Pan-STARRS moving object processing system (MOPS) and a simple model for the catastrophic disruption event's photometric behavior in a small aperture centered on the catastrophic disruption event. Our simplistic catastrophic disruption model suggests that delta m = 20 mag and 0.01 mag d-1 < tau < 0.1 mag d-1 which would imply that H0 = 28 -- strongly inconsistent with H0,B2005 = 23.26 +/- 0.02 predicted by Bottke et al. (2005) using purely collisional models. We postulate that the solution to the discrepancy is that > 99% of main belt catastrophic disruptions in the size range to which this study was sensitive (100 m) are not impact-generated, but are instead due to fainter rotational breakups, of which the recent discoveries of disrupted asteroids P/2013 P5 and P/2013 R3 are probable examples. We estimate that current and upcoming asteroid surveys may discover up to 10 catastrophic disruptions/year brighter than V = 18.5.Comment: 61 Pages, 10 Figures, 3 Table

    Violence Victimization of Young Men in Heterosexual Relationships: Does Alcohol Outlet Density Influence Outcomes?

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    This study examined whether alcohol outlet density is associated with male physical and sexual victimization by a female partner. Data were from the National Longitudinal Study of Adolescent Health (Add Health). A total of 3,179 young adult men identified a current heterosexual relationship and had complete intimate partner violence (IPV) victimization data. Almost 16% of this sample reported being the victim of physical only IPV in their relationship over the previous 12 months; an additional 6.4% were victims of sexual only or sexual and physical IPV. Multivariate analyses indicated high alcohol outlet density was associated with greater odds of experiencing physical IPV only (odds ratio [OR] = 2.07). Heavy drinkers experienced increased odds of physical and sexual IPV victimization. Alcohol outlet density should be addressed in prevention efforts

    Alcohol Outlet Density and Young Women’s Perpetration of Violence Toward Male Intimate Partners

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    This paper examines the relationships between alcohol outlet density, alcohol use, and perpetration of intimate partner violence (IPV) among young adult women in the US. Data were from Wave III of the National Longitudinal Study of Adolescent Health (Add Health; N = 4,430 in present analyses). Multinomial logistic regression was used to examine occurrence of past year IPV perpetration toward a male partner based on tract-level on-premise and off-premise alcohol outlet density, controlling for individuals’ demographic, alcohol use, and childhood abuse characteristics and neighborhood socio-demographic factors. Higher off-premise alcohol outlet density was found to be associated with young women’s perpetration of physical only IPV, controlling for individual-level and ecological factors. Alcohol use had an independent association with IPV perpetration but was not a mediator of the outlet density-IPV relationship. Findings suggest that considering alcohol-related environmental factors may help efforts aimed at preventing young women’s use of physical violence toward partners

    Relationships Among Alcohol Outlet Density, Alcohol use, and Intimate Partner Violence Victimization Among Young Women in the United States

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    Greater access to alcohol has been widely found to be associated with many negative outcomes including violence perpetration. This study examines the relationship between alcohol outlet density, alcohol use, and intimate partner violence (IPV) victimization among young women in the United States. A direct association between alcohol outlet density in one’s neighborhood and the likelihood of IPV victimization was examined. Data were from Wave III of the National Longitudinal Study of Adolescent Health (Add Health), which followed a nationally representative sample of adolescents into adulthood. Participants were young adult females age 18 to 26 at Wave III. Of the 4,571 female respondents who reported a current heterosexual relationship and had IPV data, 13.2% reported having been the victim of physical violence only and 6.5% experienced sexual only or physical and sexual violence in the relationship during the past year. In the regression models tested, there was no significant direct association between neighborhood alcohol outlet density and IPV victimization nor was there an association between outlet density and drinking behaviors, thus eliminating the possibility of an indirect association. Results of fully adjusted models indicate females who drank heavily, whether infrequently or frequently, were at significant risk for experiencing sexual only IPV or sexual and physical IPV. Asians and Native Americans were at significantly greater odds of experiencing sexual only or sexual and physical IPV compared with non-Hispanic Whites, while non-Hispanic Blacks were at significantly greater odds for physical only IPV. We conclude that a continuous measure of alcohol outlet density was not associated with IPV in models controlling for individual and other neighborhood characteristics. Young women who drink heavily, whether infrequently or frequently, have greater odds of experiencing sexual only or sexual and physical compared to abstainers. Similar to previous study findings, young women living with or married to their partner were at far greater risk of experiencing physical only and/or sexual only or sexual and physical IPV. The study adds to the growing body of literature that examines how community characteristics such as outlet density influence the likelihood of IPV

    Reducing Youth Access to Alcohol: Findings from a Community-Based Randomized Trial

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    Underage drinking continues to be an important public health problem and a challenge to the substance abuse prevention field. Community-based interventions designed to more rigorously control underage access to alcohol through retailer education and greater enforcement of underage drinking laws have been advocated as potentially effective strategies to help address this problem, but studies designed to evaluate such interventions are sparse. To address this issue we conducted a randomized trial involving 36 communities to test the combined effectiveness of five interrelated intervention components designed to reduce underage access to alcohol. The intervention was found to be effective in reducing the likelihood that retail clerks would sell alcohol to underage-looking buyers, but did not reduce underage drinking or the perceived availability of alcohol among high school students. Post hoc analyses, however, revealed significant associations between the level of underage drinking law enforcement in the intervention communities and reductions in both 30-day use of alcohol and binge drinking. The findings highlight the difficulty in reducing youth drinking even when efforts to curtail retail access are successful. Study findings also suggest that high intensity implementation of underage drinking law enforcement can reduce underage drinking. Any such effects of enhanced enforcement on underage drinking appear to be more directly attributable to an increase in perceived likelihood of enforcement and the resultant perceived inconveniences and/or sanctions to potential drinkers, than to a reduction in access to alcohol per se

    ASASSN-14ko is a Periodic Nuclear Transient in ESO 253-G003

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    We present the discovery that ASASSN-14ko is a periodically flaring AGN at the center of the galaxy ESO 253-G003. At the time of its discovery by the All-Sky Automated Survey for Supernovae (ASAS-SN), it was classified as a supernova close to the nucleus. The subsequent six years of V- and g-band ASAS-SN observations reveal that ASASSN-14ko has nuclear flares occurring at regular intervals. The seventeen observed outbursts show evidence of a decreasing period over time, with a mean period of P0=114.2±0.4P_0 = 114.2 \pm 0.4 days and a period derivative of P˙=−0.0017±0.0003\dot{P} = -0.0017\pm0.0003. The most recent outburst in May 2020, which took place as predicted, exhibited spectroscopic changes during the rise and a had a UV bright, blackbody spectral energy distribution similar to tidal disruption events (TDEs). The X-ray flux decreased by a factor of 4 at the beginning of the outburst and then returned to its quiescent flux after ~8 days. TESS observed an outburst during Sectors 4-6, revealing a rise time of 5.60±0.055.60 \pm 0.05 days in the optical and a decline that is best fit with an exponential model. We discuss several possible scenarios to explain ASASSN-14ko's periodic outbursts, but currently favor a repeated partial TDE. The next outbursts should peak in the optical on UT 2020-09-7.4± \pm 1.1 and UT 2020-12-26.5± \pm 1.4.Comment: 26 pages, 15 figures, 7 tables. Will be submitted to ApJ. The latest flare is currently ongoing, as we predicte
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