950 research outputs found

    Antisymmetric tensor contribution to the muon g-2

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    We investigate the Kalb-Ramond antisymmetric tensor field as solution to the muon g−2g-2 problem. In particular we calculate the lowest-order Kalb-Ramond contribution to the muon anomalous magnetic moment and find that we can fit the new experimental value for the anomaly by adjusting the coupling without affecting the electron anomalous magnetic moment results.Comment: 7 pages, 1 figur

    Subtleties in the quasi-classical calculation of Hawking radiation

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    he quasi-classical method of deriving Hawking radiation is investigated. In order to recover the original Hawking temperature one must take into account a previously ignored contribution coming from the temporal part of the action. This contribution plus a contribution coming from the spatial part of the action gives the correct temperature.Comment: 6 pages revtex. Honorable Mention in 2008 GRF essay contest, typos fixed, sign errors corrected. To be published in Special Issue of IJMP

    Do alcohol product labels stating lower strength verbal description, percentage alcohol‐by‐volume, or their combination affect wine consumption? A bar laboratory adaptive randomised controlled trial

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    A previous research study concluded that wine and beer labelled as lower in strength increase consumption compared with the same drinks labelled as regular strength. The label included both a verbal and numerical descriptor of strength. The present study aimed to estimate the effect of each of these label components. Adaptive, parallel group randomised controlled trial, comprising an internal pilot sample (N = 90) and a confirmatory sample (N = 57). University bar laboratory in London UK. One-hundred and forty-seven weekly wine drinkers were sampled from a nationally representative English panel. Participants were randomised to one of three groups to taste test wine in a bar-laboratory, varying only in the label displayed: (i) verbal descriptor only (Super Low); (ii) numerical descriptor only (4%ABV); and (iii) verbal descriptor and numerical descriptor combined (Super Low 4%ABV) [each group n = 49]. The primary outcome was total volume (ml) of wine consumed. Participants randomised to the numerical descriptor label group (4%ABV: M = 155.12ml, B = 20.30, 95% CI = 3.92, 36.69, p-value = 0.016) and combined verbal and numerical descriptor label group (Super Low 4%ABV: M = 154.59ml, B = 20.68, 95%CI = 4.32, 37.04, p-value = 0.014) drank significantly greater amounts than those randomised to the verbal descriptor label group (Super Low: M = 125.65ml). This bar laboratory study estimated that a greater quantity of 'lower' strength wine was consumed when the label included a numerical strength descriptor compared with a verbal only strength descriptor. [Abstract copyright: This article is protected by copyright. All rights reserved.

    Thermal radiation of various gravitational backgrounds

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    We present a simple and general procedure for calculating the thermal radiation coming from any stationary metric. The physical picture is that the radiation arises as the quasi--classical tunneling of particles through a gravitational barrier. We show that our procedure can reproduce the results of Hawking and Unruh radiation. We also show that under certain kinds of coordinate transformations the temperature of the thermal radiation will change in the case of the Schwarzschild black holes. In addition we apply our procedure to a rotating/orbiting system and show that in this case there is no radiation, which has experimental implications for the polarization of particles in circular accelerators.Comment: 6 pages revtex, added references, publication version. To be published IJMP

    A computerized Langmuir probe system

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    For low pressure plasmas it is important to record entire single or double Langmuir probe characteristics accurately. For plasmas with a depleted high energy tail, the accuracy of the recorded ion current plays a critical role in determining the electron temperature. Even for high density Maxwellian distributions, it is necessary to accurately model the ion current to obtain the correct electron density. Since the electron and ion current saturation values are, at best, orders of magnitude apart, a single current sensing resistor cannot provide the required resolution to accurately record these values. We present an automated, personal computer based data acquisition system for the determination of fundamental plasma properties in low pressure plasmas. The system is designed for single and double Langmuir probes, whose characteristics can be recorded over a bias voltage range of ±70 V with 12 bit resolution. The current flowing through the probes can be recorded within the range of 5 nA–100 mA. The use of a transimpedance amplifier for current sensing eliminates the requirement for traditional current sensing resistors and hence the need to correct the raw data. The large current recording range is realized through the use of a real time gain switching system in the negative feedback loop of the transimpedance amplifier

    Open Dialogue compared to treatment as usual for adults experiencing a mental health crisis: Protocol for the ODDESSI multi-site cluster randomised controlled trial.

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    Background 'Open Dialogue' is a social network model of crisis and continuing mental healthcare which involves elements of service delivery such as immediate response and a style of therapeutic meeting called network meetings. Although there are indications from non-randomised studies that it may help people in their recovery from severe mental health crises and improve long-term outcomes, this has yet to be tested in a randomised controlled trial. Methods This paper outlines the protocol for a multi-site cluster-randomised control trial assessing the clinical and cost-effectiveness of Open Dialogue compared to treatment as usual (TAU) for individuals presenting in crisis to six mental health services in England. The primary outcome is time to relapse, with secondary outcomes including measures of recovery and service use. Participants will be followed-up for two years, with data collected from electronic medical records and researcher-led interviews. The analysis will compare outcomes between treatment groups as well as investigating potential mediators of effect: shared decision-making and social network quality and size. Carers of a subsample of participants will be asked about their experiences of shared decision-making, carer burden, and satisfaction. Discussion This trial will provide evidence of whether Open Dialogue services implemented in the English mental health system is an effective alternative to current care and may have important implications for the organization of community mental health services. Trial registration: retrospectively registered (108 participants recruited of 570 target) on 20/12/2019, ISRCTN52653325. [Abstract copyright: Copyright © 2021. Published by Elsevier Inc.

    The neural basis of hot and cold cognition in depressed patients, unaffected relatives, and low -risk healthy controls: An fMRI investigation

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    BACKGROUND: Modern cognitive neuropsychological models of depression posit that negatively biased emotional (“hot”) processing confers risk for depression, while preserved executive function (“cold”) cognition promotes resilience. METHODS: We compared neural responses during hot and cold cognitive tasks in 99 individuals: those at familial risk for depression (N = 30 unaffected first-degree relatives of depressed individuals) and those currently experiencing a major depressive episode (N = 39 unmedicated depressed patients) with low-risk healthy controls (N = 30). Primary analyses assessed neural activation on two functional magnetic resonance imaging tasks previously associated with depression: dorsolateral prefrontal cortex (DLPFC) responsivity during the n-back working memory task; and amygdala and subgenual anterior cingulate cortex (sgACC) responsivity during incidental emotional face processing. RESULTS: Depressed patients exhibited significantly attenuated working memory-related DLPFC activation, compared to low-risk controls and unaffected relatives; unaffected relatives did not differ from low-risk controls. We did not observe a complementary pattern during emotion processing. However, we found preliminary support that greater DLPFC activation was associated with lower amygdala response during emotion processing. LIMITATIONS: These findings require confirmation in a longitudinal study to observe each individual's risk of developing depression; without this, we cannot identify the true risk level of the first-degree relative or low-risk control group. CONCLUSIONS: These findings have implications for understanding the neural mechanisms of risk and resilience in depression: they are consistent with the suggestion that preserved executive function might confer resilience to developing depression in first-degree relatives of depressed patients

    Communicating the effectiveness and ineffectiveness of government policies and their impact on public support: a systematic review with meta-analysis.

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    Low public support for government interventions in health, environment and other policy domains can be a barrier to implementation. Communicating evidence of policy effectiveness has been used to influence attitudes towards policies, with mixed results. This review provides the first systematic synthesis of such studies. Eligible studies were randomized controlled experiments that included an intervention group that provided evidence of a policy's effectiveness or ineffectiveness at achieving a salient outcome, and measured policy support. From 6498 abstracts examined, there were 45 effect sizes from 36 eligible studies. In total, 35 (N = 30 858) communicated evidence of effectiveness, and 10 (N = 5078) communicated evidence of ineffectiveness. Random effects meta-analysis revealed that communicating evidence of a policy's effectiveness increased support for the policy (SMD = 0.11, 95% CI [0.07, 0.15], p < 0.0001), equivalent to support increasing from 50% to 54% (95% CI [53%, 56%]). Communicating evidence of ineffectiveness decreased policy support (SMD = -0.14, 95% CI [-0.22, -0.06], p < 0.001), equivalent to support decreasing from 50% to 44% (95% CI [41%, 47%]). These findings suggest that public support for policies in a range of domains is sensitive to evidence of their effectiveness, as well as their ineffectiveness
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