397 research outputs found

    Low Frequency Gravitational Waves from White Dwarf MACHO Binaries

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    The possibility that Galactic halo MACHOs are white dwarfs has recently attracted much attention. Using the known properties of white dwarf binaries in the Galactic disk as a model, we estimate the possible contribution of halo white dwarf binaries to the low-frequency (10^{-5} Hz} < f < 10^{-1}Hz) gravitational wave background. Assuming the fraction of white dwarfs in binaries is the same in the halo as in the disk, we find the confusion background from halo white dwarf binaries could be five times stronger than the expected contribution from Galactic disk binaries, dominating the response of the proposed space based interferometer LISA. Low-frequency gravitational wave observations will be the key to discovering the nature of the dark MACHO binary population.Comment: 9 pages, 1 figure, AASTe

    Mediatization of Emotion on Social Media: Forms and Norms in Digital Mourning Practices

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    This article provides the theoretical background for this Special Issue which explores the mediatization of emotion on social media as attested in different digital mourning practices. The overview discusses the affective and emotional turn alongside the mediatic turn in relation to key trends and foci in the study of affect/emotion. Our discussion points to a shift in conceptualizations of affect/emotion from mediated to mediatized practice, embedded in other social practices and subject to media and social media logics, affordances, and frames, which are worthy of empirical investigation. The article also presents key insights offered in the four articles of this Special Issue and foregrounds current and future directions in the study of mediatization, emotional sharing, and digital mourning practices

    Targeted Enforcement against Illicit Trade in Tobacco Products

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    Illicit trade in tobacco is a substantial and growing problem in the U.S., causing loss of tax revenue, damage to public health, and threats to public safety. Decisions about enforcement against ITTP involve tradeoffs among competing objectives. Good policy design can improve the terms of those tradeoffs but cannot eliminate them. We examine questions about the allocation of enforcement resources against ITTP, and its distribution across activities, individuals, and organizations: in particular, whether and how to differentially target ITTP that involves violence or support for terrorism. We consider the problem of developing effective strategies for enforcement, applying both lessons from experience with markets for illicit drugs and theoretical insights about enforcement targeting and dynamic concentration. We show that targeted enforcement and focused deterrence are more efficient than unfocused enforcement, and that – when other policy changes increase the potential rewards to illicit activity – enforcement resources applied earlier (before illicit markets have grown) will have greater impact than enforcement resources applied later (and therefore to larger markets). We discuss additional considerations, ranging from real-world complications left out of the simple models to examination of how insights from behavioral law and economics may modify conclusions based on a theory of deterrence designed for homo economicus

    The impact of percieved procedural justice on health, HIV risk behaviors, substance use, and offending in juvenile offenders

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    Research into the impact of perceived discrimination and health has shown that it is related to poorer health status and health behaviors compared to those who perceive less discrimination. Perceived procedural injustice, however, may also have implications for health and health behaviors. Due to the evidence on perceived discrimination and its impact health and health-related behaviors, it is suggested that perceived procedural injustice—a concept similar to perceived discrimination—will have a similar impact on health through similar mechanisms (which include health-related behaviors and a stress response). The current study seeks to examine whether perceived procedural justice is related to poor health via psychological distress, substance use, HIV risk behaviors, or offending using archival data from the Pathways to Desistance Study. The Pathways to Desistance Study was a longitudinal study, which collected data from November of 2000 through March of 2010, from adjudicated youth from Phoenix, Arizona and Philadelphia, Pennsylvania. Results indicated a significant positive association between perceived procedural justice change scores and psychological distress change scores, in the opposite direction as hypothesized. No significant associations between psychological distress and offending, HIV risk behaviors, substance use, and self-reported health occurred. However, significant negative associations occurred between perceived procedural justice and substance use, as well as perceived procedural justice and offending, although no significant associations occurred between perceived procedural justice change scores and health or HIV risk behaviors. Significant, positive associations occurred between offending, substance use, and HIV risk behaviors, as expected. Overall, results of the study were inconsistent with prior research examining the relationship between perceived discrimination and health. Possible explanations of contrary and unexpected results are discussed, along with limitations of the study

    Countervailing Effects: What the FDA Would Have to Know to Evaluate Tobacco Regulations

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    The Family Smoking Prevention and Tobacco Control Act [P.L. 111-31] gives the US Food and Drug Administration (FDA) the authority to regulate tobacco products, including placing restrictions on product composition, sale, and distribution. A complete accounting of the costs and benefits of any tobacco regulation includes harms from possible illicit trade in tobacco products (ITTP): costs of enforcement, violence, incarceration, etc. Indeed, the law instructs the FDA to take into account the “countervailing effects” of regulation on public health, “such as the creation of a significant demand for contraband or other tobacco products that do not meet the requirements.” While the law’s narrow focus on public health may limit the scope of an inquiry by the FDA compared to a full benefit-cost analysis, aspects of ITTP such as violence and incarceration have substantial health impacts. Illicit markets in drugs such as cocaine, heroin, and methamphetamine, not to mention the grand experiment of alcohol Prohibition in the early 20th century, illustrate the substantial risks of unwanted side effects of drug prohibition. But taxes, product limitations, access restrictions, and narrowly defined product bans constitute “lesser prohibitions,” and are subject to the same kind (if not degree) of risks. All tobacco policy-making should therefore consider ITTP. This article sets forth a research agenda for the FDA to consider in order to estimate the effects of contemplated tobacco-product regulation and ITTP. We argue that, to carry out fully its legislative mandate, the FDA would have to determine the current size and impact of ITTP, analyze how these may be expected to change under new regulations, and look for interdependencies among tobacco-product markets that may complicate single-product regulation. A more challenging element of the research agenda would be to develop a better theoretical groundwork for the prediction of the emergence, size, and side effects of illicit markets

    Unintended Consequences of Cigarette Prohibition, Regulation, and Taxation

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    Abstract Laws that prohibit, regulate, or tax cigarettes can generate illicit markets for tobacco products. Illicit markets both reduce the efficacy of policies intended to improve public health and create harms of their own. Enforcement can reduce evasion but creates additional harms, including incarceration and violence. There is strong evidence that more enforcement in illicit drug markets can spur violence. The presence of licit substitutes, such as electronic cigarettes, has the potential to greatly reduce the size of illicit markets. We present a model demonstrating why enforcement can increase violence, show that states with higher tobacco taxes have larger illicit markets, and apply the findings to discussion of public policy toward a potential ban on menthol cigarettes. The social calculus involved in determining public policy toward tobacco cigarettes should include the harms from both consumption and control. We conclude by highlighting areas where more research is needed for effective policymaking

    Material Support: Counternarcotics vs. Counterinsurgency in Afghanistan

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    Microeconomic analysis of counternarcotics strategies in Afghanistan suggests that current policies lend material support to the enemy. Vigorous enforcement can increase the flow of funds to insurgents and other parties that profit from trafficking. Rural-development programs, promoted as elements of a counternarcotics strategy, are open to some of the same objections. The benefits of drug-fighting in Afghanistan for consumer countries in Europe and North America are likely to be modest. Anti-corruption efforts in Afghanistan and demand-reduction programs both in Afghanistan and in consumer countries, insofar as they are feasible, could serve both counternarcotics and counterinsurgency objectives

    Design Improved Parimutuel-type Information Aggregation Mechanisms: Inaccuracies and the Long-Shot Bias as Disequilibrium Phenomena

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    Information Aggregation Mechanisms (IAMs) based on parimutuel-type betting systems can aggregate information from complex environments. However, the performance of previously studied systems leaves something to be desired due to possible bluffing, strategic timing of decisions and a so called long shot bias. This paper demonstrates that two modifications of parimutuel systems improve information aggregation performance by removing disinformation due to strategic behavior and by removing misleading disequilibrium behavior. The experiments also demonstrate that the so called long shot bias results from disequilibrium behavior as opposed to having roots in the psychology of the individuals

    Anomalous asymmetry of magnetoresistance in NbSe3_3 single crystals

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    A pronounced asymmetry of magnetoresistance with respect to the magnetic field direction is observed for NbSe3_3 crystals placed in a magnetic field perpendicular to their conducting planes. It is shown that the effect persists in a wide temperature range and manifests itself starting from a certain magnetic induction value B0B_0, which at T=4.2T=4.2 K corresponds to the transition to the quantum limit, i.to the state where the Landay level splitting exceeds the temperature.Comment: 4 pages, 6 figures, to be appeared in JETP Let

    Mosaic DNA imports with interspersions of recipient sequence after natural transformation of Helicobacter pylori

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    Helicobacter pylori colonizes the gastric mucosa of half of the human population, causing gastritis, ulcers, and cancer. H. pylori is naturally competent for transformation by exogenous DNA, and recombination during mixed infections of one stomach with multiple H. pylori strains generates extensive allelic diversity. We developed an in vitro transformation protocol to study genomic imports after natural transformation of H. pylori. The mean length of imported fragments was dependent on the combination of donor and recipient strain and varied between 1294 bp and 3853 bp. In about 10% of recombinant clones, the imported fragments of donor DNA were interrupted by short interspersed sequences of the recipient (ISR) with a mean length of 82 bp. 18 candidate genes were inactivated in order to identify genes involved in the control of import length and generation of ISR. Inactivation of the antimutator glycosylase MutY increased the length of imports, but did not have a significant effect on ISR frequency. Overexpression of mutY strongly increased the frequency of ISR, indicating that MutY, while not indispensable for ISR formation, is part of at least one ISR-generating pathway. The formation of ISR in H. pylori increases allelic diversity, and contributes to the uniquely low linkage disequilibrium characteristic of this pathogen
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