606 research outputs found

    Searching for physics beyond the Standard Model through the dipole interaction

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    The magnetic dipole interaction played a central role in the development of QED, and continued in that role for the Standard Model. The muon anomalous magnetic moment has served as a benchmark for models of new physics, and the present experimental value is larger than the standard-model value by more than three standard deviations. The electric dipole moment (EDM) violates parity ({PP}) and time-reversal ({TT}) symmetries, and in the context of the CPTCPT theorem, the combination of charge conjugation and parity (CPCP). Since a new source of {CP CP} violation outside of that observed in the KK and BB meson systems is needed to help explain the baryon asymmetry of the universe, searches for EDMs are being carried out worldwide on a number of systems. The standard-model value of the EDM is immeasurably small, so any evidence for an EDM would signify the observation of new physics. Unique opportunities exist for EDM searches using polarized proton, deuteron or muon beams in storage rings. This talk will provide an overview of the theory of dipole moments, and the relevant experiments. The connection to the transition dipole moment that could produce lepton flavor violating interactions such as μ+e+γ\mu^+ \rightarrow e^+ \gamma is also mentioned.Comment: Invited Plenary talk at the 19th International Spin Physics Symposium, Juelic

    Review of teacher recruitment, supply and retention in Wales

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    The brief for this project was to complete "a detailed desk based study of existing secondary sources on teacher recruitment and retention" (GTCW, 2002, p. 8) comprising two related research activities: a search of existing literature in the area and the collection and analysis of relevant secondary data. Where possible, the project was also to make recommendations for policy, data collection and further research. The report has the following structure: 1. Sources of information on teacher supply 2. The demand for teachers 3. Teacher recruitment and retention 4. Implications for policy 5. Recommendations for further research 6. References used in the text Appendix A: Limitations of, and problems with, the available dat

    Serotonin at the level of the amygdala and orbitofrontal cortex modulates distinct aspects of positive emotion in primates.

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    Impaired top-down regulation of the amygdala, and its modulation by serotonin (5-HT), is strongly implicated in the dysregulation of negative emotion that characterizes a number of affective disorders. However, the contribution of these mechanisms to the regulation of positive emotion is not well understood. This study investigated the role of 5-HT within the amygdala and the orbitofrontal cortex (OFC), on the expression of appetitive Pavlovian conditioned emotional responses and their reversal in a primate, the common marmoset. Its effects were compared to those of the amygdala itself. Having developed conditioned autonomic and behavioural responses to an appetitive cue prior to surgery, marmosets with excitotoxic amygdala lesions failed to display such conditioned autonomic arousal at retention, but still displayed intact cue-directed conditioned behaviours. In contrast, 5,7-DHT infusions into the amygdala, reducing extracellular 5-HT levels, selectively enhanced the expression of appetitive conditioned behaviour at retention. Similar infusions into the OFC, producing marked reductions in post-mortem 5-HT tissue levels, had no overall effect on autonomic or behavioural responses, either at retention or during reversal learning, but caused an uncoupling of these responses, thereby fractionating emotional output. These data demonstrate the critical role of the amygdala in the expression of appetitive autonomic conditioning, and the region-selective contribution of 5-HT in the amygdala and OFC, respectively, to the expression of conditioned behaviour and the overall coordination of the emotional response. They provide insight into the neurochemical mechanisms underlying the regulation of positive emotional responses, advancing our understanding of the neural basis of pathologically dysregulated emotion

    Patients’ experiences of clinical team meetings (ward rounds) at an adult in-patient eating disorders ward: mixed-method service improvement project

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    Aims Ward rounds are key to treatment-related decision-making, but are often stressful. This project aimed to explore and improve patients’ experiences of the clinical team meeting (CTM; historically known as ward round) in an adult in-patient eating disorders unit. A mixed-method approach was adopted with in vivo observations, two focus groups and an interview. Six patients participated. Two former patients contributed to data analysis, co-production of service improvement initiatives and write-up. Results The mean CTM duration was 14.3 min. Patients spoke half of the time, followed by psychiatry colleagues. ‘Request’ was the most discussed category. Three themes were identified: CTMs are important but impersonal, a sense of palpable anxiety was generated and staff and patients had divergent views regarding CTM goals. Clinical implications The co-produced changes to CTMs were implemented and improved patient's experiences despite COVID-19 challenges. Factors beyond CTMs, including the ward's power hierarchy, culture and language, need addressing to facilitate shared decision-making

    No Dynamics in the Extremal Kerr Throat

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    Motivated by the Kerr/CFT conjecture, we explore solutions of vacuum general relativity whose asymptotic behavior agrees with that of the extremal Kerr throat, sometimes called the Near-Horizon Extreme Kerr (NHEK) geometry. We argue that all such solutions are diffeomorphic to the NHEK geometry itself. The logic proceeds in two steps. We first argue that certain charges must vanish at all times for any solution with NHEK asymptotics. We then analyze these charges in detail for linearized solutions. Though one can choose the relevant charges to vanish at any initial time, these charges are not conserved. As a result, requiring the charges to vanish at all times is a much stronger condition. We argue that all solutions satisfying this condition are diffeomorphic to the NHEK metric.Comment: 42 pages, 3 figures. v3: minor clarifications and correction
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