1,944 research outputs found

    Poincar\'e Invariant Quantum Field Theories With Twisted Internal Symmetries

    Full text link
    Following up the work of [1] on deformed algebras, we present a class of Poincar\'e invariant quantum field theories with particles having deformed internal symmetries. The twisted quantum fields discussed in this work satisfy commutation relations different from the usual bosonic/fermionic commutation relations. Such twisted fields by construction are nonlocal in nature. Despite this nonlocality we show that it is possible to construct local interaction Hamiltonians which satisfy cluster decomposition principle and are Lorentz invariant. We further illustrate these ideas by considering global SU(N) symmetries. Specifically we show that twisted internal symmetries can significantly simplify the discussion of the marginal deformations (\beta-deformations) of the N=4 SUSY theories.Comment: 27 pages, Typos Corrected, Text and Conclusions Unchanged, Version published in JHE

    Increasing incidence of childhood leukaemia: a controversy re-examined

    Get PDF
    We provide evidence of a gradual increase in the incidence of childhood leukaemia over the twentieth century from examination of trends in both incidence and mortality in England and Wales. We conclude that much of the recorded increase is likely to be real

    Unintended Consequences of Incentive Provision for Behaviour Change and Maintenance around Childbirth

    Get PDF
    Financial (positive or negative) and non-financial incentives or rewards are increasingly used in attempts to influence health behaviours. While unintended consequences of incentive provision are discussed in the literature, evidence syntheses did not identify any primary research with the aim of investigating unintended consequences of incentive interventions for lifestyle behaviour change. Our objective was to investigate perceived positive and negative unintended consequences of incentive provision for a shortlist of seven promising incentive strategies for smoking cessation in pregnancy and breastfeeding. A multi-disciplinary, mixed-methods approach included involving two service-user mother and baby groups from disadvantaged areas with experience of the target behaviours as study co-investigators. Systematic reviews informed the shortlist of incentive strategies. Qualitative semi-structured interviews and a web-based survey of health professionals asked open questions on positive and negative consequences of incentives. The participants from three UK regions were a diverse sample with and without direct experience of incentive interventions: 88 pregnant women/recent mothers/partners/family members; 53 service providers; 24 experts/decision makers and interactive discussions with 63 conference attendees. Maternity and early years health professionals (n = 497) including doctors, midwives, health visitors, public health and related staff participated in the survey. Qualitative analysis identified ethical, political, cultural, social and psychological implications of incentive delivery at population and individual levels. Four key themes emerged: how incentives can address or create inequalities; enhance or diminish intrinsic motivation and wellbeing; have a positive or negative effect on relationships with others within personal networks or health providers; and can impact on health systems and resources by raising awareness and directing service delivery, but may be detrimental to other health care areas. Financial incentives are controversial and generated emotive and oppositional responses. The planning, design and delivery of future incentive interventions should evaluate unexpected consequences to inform the evidence for effectiveness, cost-effectiveness and future implementation

    Universal time-dependent deformations of Schrodinger geometry

    Get PDF
    We investigate universal time-dependent exact deformations of Schrodinger geometry. We present 1) scale invariant but non-conformal deformation, 2) non-conformal but scale invariant deformation, and 3) both scale and conformal invariant deformation. All these solutions are universal in the sense that we could embed them in any supergravity constructions of the Schrodinger invariant geometry. We give a field theory interpretation of our time-dependent solutions. In particular, we argue that any time-dependent chemical potential can be treated exactly in our gravity dual approach.Comment: 24 pages, v2: references adde

    Holographic aspects of three dimensional QCD from string theory

    Full text link
    We study two aspects of 3D QCD with massless fermions in a holographic set-up from string theory, based on D3/D7 branes; parity anomaly and baryons as baby Skyrmions. We first give a novel account of parity anomaly of 3D QCD with odd number of flavors from the IR holographic viewpoint by observing a subtle point in D7 brane embeddings with a given fixed UV theory. We also discuss its UV origin in terms of weakly coupled D-brane pictures. We then focus on the parity-symmetric case of even number of N_F flavors, and study baryons in the holographic model. We identify the monopoles of U(N_F) gauge theory dynamically broken down to U(N_F/2)x U(N_F/2) in the holographic 4 dimensional bulk as a holographic counter-part of 3D baby-Skyrmions for baryons in large N limit, and work out some details how the mapping goes. In particular, we show that the correct baryon charges emerge from the Witten effect with a space-varying theta angle.Comment: 33 pages, 10 figures; v2: references added with comments, typos corrected; v3: more references added; v4: holographic baryon profile and the analysis of its baryon charge is significantly revised, correcting errors in the previous discussio

    Social capital in relation to depression, musculoskeletal pain, and psychosomatic symptoms: a cross-sectional study of a large population-based cohort of Swedish adolescents

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Social capital has lately received much attention in health research. The present study investigated whether two measures of subjective social capital were related to psychosomatic symptoms, musculoskeletal pain, and depression in a large population of Swedish adolescents.</p> <p>Methods</p> <p>A total of 7757 13-18 year old students anonymously completed the Survey of Adolescent Life in Vestmanland 2008 which included questions on sociodemographic background, neighbourhood social capital, general social trust, and ill health.</p> <p>Results</p> <p>Low neighbourhood social capital and low general social trust were associated with higher rates of psychosomatic symptoms, musculoskeletal pain, and depression. Individuals with low general social trust had more than three times increased odds of being depressed, three times increased odds of having many psychosomatic symptoms, and double the odds of having many symptoms of musculoskeletal pain.</p> <p>Conclusions</p> <p>The findings make an important contribution to the social capital - health debate by demonstrating relations between social capital factors and self-reported ill health in a young population.</p

    Mortality after discharge from long-term psychiatric care in Scotland, 1977 – 94: a retrospective cohort study

    Get PDF
    BACKGROUND: Recent United Kingdom strategies focus on preventable suicide deaths in former psychiatric in-patients, but natural causes of death, accidents and homicide may also be important. This study was intended to find the relative importance of natural and unnatural causes of death in people discharged from long-term psychiatric care in Scotland in 1977 –1994. METHODS: People discharged alive from psychiatric hospitals in Scotland in 1977 – 94 after a stay of one year or longer were identified using routine hospital records. Computer record linkage was used to link hospital discharges to subsequent death records. Mortality was described using a person-years analysis, and compared to the general population rates. RESULTS: 6,776 people were discharged in the time period. 1,994 people (29%) died by the end of follow-up, 732 more deaths than expected. Deaths from suicide, homicide, accident and undetermined cause were increased, but accounted for only 197 of the excess deaths. Deaths from respiratory disease were four times higher than expected, and deaths from other causes, including cardiovascular disease, were also elevated. CONCLUSION: Suicide is an important cause of preventable mortality, but natural causes account for more excess deaths. Prevention activities should not focus only on unnatural causes of death

    Considerations for spectroscopy of liquid-exfoliated 2D materials: emerging photoluminescence of N-methyl-2-pyrrolidone

    Get PDF
    N-methyl-2-pyrrolidone (NMP) has been shown to be the most effective solvent for liquid phase exfoliation and dispersion of a range of 2D materials including graphene, molybdenum disulphide (MoS2) and black phosphorus. However, NMP is also known to be susceptible to sonochemical degradation during exfoliation. We report that this degradation gives rise to strong visible photoluminescence of NMP. Sonochemical modifcation is shown to infuence exfoliation of layered materials in NMP and the optical absorbance of the solvent in the dispersion. The emerging optical properties of the degraded solvent present challenges for spectroscopy of nanomaterial dispersions; most notably the possibility of observing solvent photoluminescence in the spectra of 2D materials such as MoS2, highlighting the need for stable solvents and exfoliation processes to minimise the infuence of solvent degradation on the properties of liquid-exfoliated 2D materials
    corecore