27,569 research outputs found

    The Police Response to Active Shooter Incidents

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    There have been many active shooter incidents in the United States since Columbine, and police agencies continue to modify their policies and training to reflect the lessons that are learned from each new tragedy. This report summarizes the state of the field as of 2014. The Police Executive Research Forum conducted research on these issues and held a one-day Summit in Washington, D.C., in which an overflow crowd of more than 225 police chiefs and other officials discussed the changes that have occurred, and where they are going from here

    How Misinformation Spreads Through Twitter

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    While living in the age of information, an inherent drawback to such high exposure to content lends itself to the precarious rise of misinformation. Whether it is called “alternative facts,” “fake news,” or just incorrect information, because of its pervasiveness in nearly every political and policy discussion, the spread of misinformation is seen as one of the greatest challenges to overcome in the 21st century. As new technologies emerge, a major piece of both content creation and the perpetuation of misinformation are social media platforms like Twitter, Facebook, and YouTube. As news events emerge, whether be a pandemic, a mass shooting, or an election campaign, it is difficult to divulge the facts from fiction when so many different “facts” appear. This study looks at 14,545,945 tweets generated in the wake of the 1 October mass shooting and its second anniversary to identify how much of the public response is fogged by information pollution, to identify what kind of misinformation is spread and how it spreads on Twitter and news coverage

    First VLT/X-shooter spectroscopy of early-type stars outside the Local Group

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    As part of the VLT/X-shooter science verification, we obtained the first optical medium-resolution spectrum of a previously identified bright O-type object in NGC55, an LMC-like galaxy at a distance of \sim2.0 Mpc. Based on the stellar and nebular spectrum, we investigate the nature and evolutionary status of the central object(s) and its influence on the surrounding interstellar medium. We conclude that the source, NGC55_C1_31, is a composite object, likely a stellar cluster, which contains one or several hot (T_eff \simeq 50000 K) WN stars with a high mass-loss rate (\sim3 \times 10^{-5} M_\odot yr^{-1}) and a helium-rich composition (N_He/N_H = 0.8). The visual flux is dominated by OB-type (super)giant stars with T_eff \sim< 35000 K, solar helium abundance (N_He/N_H = 0.1), and mass-loss rate \sim2 \times 10^{-6} M_\odot yr^{-1}. The surrounding H II region has an electron density n_e < 10^2 cm^{-3} and an electron temperature T(OIII) \simeq 11500 \pm 600 K. The oxygen abundance of this region is [O/H] = 8.18 \pm 0.03 which corresponds to Z = 0.31 \pm 0.04 Z_\odot. We observed no significant gradients in T(OIII), n_e or [O/H] on a scale of 73 pc extending in four directions from the ionising source. The properties of the HII region can be reproduced by a CLOUDY model which uses the central cluster as ionising source, thus providing a self-consistent interpretation of the data. We also report on the serendipitous discovery of HeII nebular emission associated with the nearby source NGC55_C2_35, a feature usually associated with strong X-ray sources.Comment: 12 pages, 10 figures, accepted for publication in Monthly Notices of the Royal Astronomical Society; the definitive version will be available at wwww.blackwell-synergy.co

    Variables Predicting the Severity of a Mass Shooting: the connection to white supremacy

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    Since mass shootings have become increasingly relevant in today’s society, the subject of what makes a mass shooting deadly has become more and more popular. This project focuses on how selected variables correlate with the severity of a mass shooting, and especially focuses on the impact of white supremacy ideology. Theoretically, a shooter imbued with this ideology will likely be more violent, thus causing a higher victim count (injuries + deaths). The other variables included in the model are: the use of a long gun, the use of multiple guns, the use of semi-automatic guns, mental illness, and shooter suicide. This project seeks to assess the relationships of these variables to the victim count, and the statistical significance of each of these relationships. By drawing from two prominent mass-shooting databases and associated media sources, a dataset was constructed, then analyzed with correlation, regression, and ANOVA. These analyses confirmed all of the hypotheses, with predictor variable correlating positively and significantly to victim count. Most importantly, the findings confirmed the significance of the white supremacy ideology variable in predicting the violence of a mass shooting, and the effect withstood the introduction of a variety of important control variables; in short, shooters with a white supremacy background tend to inflict a higher victim count during a mass shooting. Based on these findings, suggestions for further research include separating active-shooter mass shootings from other types of mass shootings; standardizing the operational definition of a mass shooting; and increasing the number of possible predictor variables in current mass shooting databases

    PersonRank: Detecting Important People in Images

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    Always, some individuals in images are more important/attractive than others in some events such as presentation, basketball game or speech. However, it is challenging to find important people among all individuals in images directly based on their spatial or appearance information due to the existence of diverse variations of pose, action, appearance of persons and various changes of occasions. We overcome this difficulty by constructing a multiple Hyper-Interaction Graph to treat each individual in an image as a node and inferring the most active node referring to interactions estimated by various types of clews. We model pairwise interactions between persons as the edge message communicated between nodes, resulting in a bidirectional pairwise-interaction graph. To enrich the personperson interaction estimation, we further introduce a unidirectional hyper-interaction graph that models the consensus of interaction between a focal person and any person in a local region around. Finally, we modify the PageRank algorithm to infer the activeness of persons on the multiple Hybrid-Interaction Graph (HIG), the union of the pairwise-interaction and hyperinteraction graphs, and we call our algorithm the PersonRank. In order to provide publicable datasets for evaluation, we have contributed a new dataset called Multi-scene Important People Image Dataset and gathered a NCAA Basketball Image Dataset from sports game sequences. We have demonstrated that the proposed PersonRank outperforms related methods clearly and substantially.Comment: 8 pages, conferenc
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