2,332 research outputs found

    Relation between parameters of dust and parameters of molecular and atomic gas in extragalactic star-forming regions

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    The relationships between atomic and molecular hydrogen and dust of various sizes in extragalactic star-forming regions are considered, based on observational data from the Spitzer and Herschel infrared space telescopes, the Very Large Array (atomic hydrogen emission) and IRAM (CO emission). The source sample consists of approximately 300 star-forming regions in 11 nearby galaxies. Aperture photometry has been applied to measure the fluxes in eight infrared bands (3.6, 4.5, 5.8, 8, 24, 70, 100, and 160μ\mum), the atomic hydrogen (21cm) line and CO (2--1) lines. The parameters of the dust in the starforming regions were determined via synthetic-spectra fitting, such as the total dust mass, the fraction of polycyclic aromatic hydrocarbons (PAHs), etc. Comparison of the observed fluxes with the measured parameters shows that the relationships between atomic hydrogen, molecular hydrogen, and dust are different in low- and high-metallicity regions. Low-metallicity regions contain more atomic gas, but less molecular gas and dust, including PAHs. The mass of dust constitutes about 1%1\% of the mass of molecular gas in all regions considered. Fluxes produced by atomic and molecular gas do not correlate with the parameters of the stellar radiation, whereas the dust fluxes grow with increasing mean intensity of stellar radiation and the fraction of enhanced stellar radiation. The ratio of the fluxes at 8 and 24μ\mum, which characterizes the PAH content, decreases with increasing intensity of the stellar radiation, possibly indicating evolutionary variations of the PAH content. The results confirm that the contribution of the 24μ\mum emission to the total IR luminosity of extragalactic star-forming regions does not depend on the metallicity.Comment: Published in Astronomy Reports, 2017, vol. 61, issue

    Evaluating the Impact of Florida's "Stand Your Ground" Self-defense Law on Homicide and Suicide by Firearm: An Interrupted Time Series Study.

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    Importance: In 2005, Florida amended its self-defense laws to provide legal immunity to individuals using lethal force in self-defense. The enactment of "stand your ground" laws in the United States has been controversial and their effect on rates of homicide and homicide by firearm is uncertain. Objective: To estimate the impact of Florida's stand your ground law on rates of homicide and homicide by firearm. Design, Setting, and Participants: Using an interrupted time series design, we analyzed monthly rates of homicide and homicide by firearm in Florida between 1999 and 2014. Data were collected from the Wide-ranging Online Data for Epidemiologic Research (WONDER) web portal at the Centers for Disease Control and Prevention. We used seasonally adjusted segmented Poisson regression models to assess whether the onset of the law was associated with changes in the underlying trends for homicide and homicide by firearm in Florida. We also assessed the association using comparison states without stand your ground laws (New York, New Jersey, Ohio, and Virginia) and control outcomes (all suicides and suicides by firearm in Florida). October 1, 2005, the effective date of the law, was used to define homicides before and after the change. Main Outcomes and Measures: Monthly rates of homicide, firearm-related homicide, suicide, and suicide by firearm in Florida and the 4 comparison states. Results: Prior to the stand your ground law, the mean monthly homicide rate in Florida was 0.49 deaths per 100 000 (mean monthly count, 81.93), and the rate of homicide by firearm was 0.29 deaths per 100 000 (mean monthly count, 49.06). Both rates had an underlying trend of 0.1% decrease per month. After accounting for underlying trends, these results estimate that after the law took effect there was an abrupt and sustained increase in the monthly homicide rate of 24.4% (relative risk [RR], 1.24; 95%CI, 1.16-1.33) and in the rate of homicide by firearm of 31.6% (RR, 1.32; 95% CI, 1.21-1.44). No evidence of change was found in the analyses of comparison states for either homicide (RR, 1.06; 95% CI, 0.98-1.13) or homicide by firearm (RR, 1.08; 95% CI, 0.99-1.17). Furthermore, no changes were observed in control outcomes such as suicide (RR, 0.99; 95% CI, 0.94-1.05) and suicide by firearm (RR, 0.98; 95% CI, 0.91-1.06) in Florida between 2005 and 2014. Conclusions and Relevance: The implementation of Florida's stand your ground self-defense law was associated with a significant increase in homicides and homicides by firearm but no change in rates of suicide or suicide by firearm

    Extraction and measurement of adenosine triphosphate from marine sediment, The

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    Includes bibliographical references (pages 479-480).A technique has been developed, using boiling sodium bicarbonate buffer, to extract adenosine triphosphate (ATP) from marine sediments and has been tested on a variety of sediments, including those with high organic content, clay, and carbonate. Recovery of ATP, as measured by the addition of bacteria of known ATP content to sediment, varied from 64-100%. The technique also was as effective as the conventional Tris buffer for extraction of ATP from both pure cultures of bacteria grown in broth and natural seawater samples.Publisher version: http://www.jstor.org/stable/2835285

    Modelling future interlinkages

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    Evaluating the impact of flexible alcohol trading hours on violence: an interrupted time series analysis.

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    BACKGROUND: On November 24(th) 2005, the Government of England and Wales removed regulatory restrictions on the times at which licensed premises could sell alcohol. This study tests availability theory by treating the implementation of Licensing Act (2003) as a natural experiment in alcohol policy. METHODS: An interrupted time series design was employed to estimate the Act's immediate and delayed impact on violence in the City of Manchester (Population 464,200). We collected police recorded rates of violence, robbery, and total crime between the 1st of February 2004 and the 31st of December 2007. Events were aggregated by week, yielding a total of 204 observations (95 pre-, and 109 post-intervention). Secondary analysis examined changes in daily patterns of violence. Pre- and post-intervention events were separated into four three-hour segments 18∶00-20∶59, 21∶00-23.59, 00∶00-02∶59, 03∶00-05∶59. RESULTS: Analysis found no evidence that the Licensing Act (2003) affected the overall volume of violence. However, analyses of night-time violence found a gradual and permanent shift of weekend violence into later parts of the night. The results estimated an initial increase of 27.5% between 03∶00 to 06∶00 (ω = 0.2433, 95% CI = 0.06, 0.42), which increased to 36% by the end of the study period (δ = -0.897, 95% CI = -1.02, -0.77). CONCLUSIONS: This study found no evidence that a national policy increasing the physical availability of alcohol affected the overall volume of violence. There was, however, evidence suggesting that the policy may be associated with changes to patterns of violence in the early morning (3 a.m. to 6 a.m.)

    Exploring opportunities around climate-smart breeding for future food and nutrition security

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    There is a 95% chance that warming will exceed 2°C by the end of the century (Raftery et al. 2017). Global crop productivity is projected to fall by 5-10 % per degree of warming (Challinor et al. 2014), with even greater losses likely for some crops in some areas. The challenge of meeting future food demand is increasing, and climate change is already diminishing our ability to adapt through crop breeding (Challinor et al. 2016; Aggarwal et al. 2019). Recent research is suggesting that increases in climate variability are already affecting the number of food-insecure people, and that increasing atmospheric CO2 concentrations may affect the nutrient content of some food staples, with serious implications for food and nutrition security (Smith and Myers 2018). New crop varieties will be needed that can deliver higher yields as well as possessing the ability to withstand heat and greater tolerances for the secondary effects of a warmer world, such as increased pressures from drought, water-logging, pests and diseases, and reduced nutritional quality due to higher levels of CO2. The systems for accelerated delivery of climate-resilient varieties into food producers’ hands need to be massively upgraded (Cramer 2018). Innovative holistic breeding strategies for multiple traits will be needed that embrace the full pipeline from trait discovery to varietal deployment and seed system development
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