2,081 research outputs found

    Harmonic Superspaces and Superconformal Fields

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    Representations of four-dimensional superconformal groups on harmonic superfields are discussed. It is argued that any representation can be given as a superfield on many superflag manifolds. Representations on analytic superspaces do not require constraints. We discuss short representations and how to obtain them as explicit products of fundamental fields. We also discuss superfields that transform under supergroups.Comment: 7 pages, JHEP Proceedings style. Contribution to the Proceedings of the TMR Conference "Non-Perturbative Quantum Effects 2000," Paris, September 200

    On Four-Point Functions of Half-BPS Operators in General Dimensions

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    We study four-point correlation functions of half-BPS operators of arbitrary weight for all dimensions d=3,4,5,6 where superconformal theories exist. Using harmonic superspace techniques, we derive the superconformal Ward identities for these correlators and present them in a universal form. We then solve these identities, employing Jack polynomial expansions. We show that the general solution is parameterized by a set of arbitrary two-variable functions, with the exception of the case d=4, where in addition functions of a single variable appear. We also discuss the operator product expansion using recent results on conformal partial wave amplitudes in arbitrary dimension.Comment: The discussion of the case d=6 expanded; references added/correcte

    Validation of a model of regulation in the tryptophan operon against multiple experiment data using global optimisation

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    This paper is concerned with validating a mathematical model of regulation in the tryptophan operon using global optimization. Although a number of models for this biochemical network are proposed, in many cases only qualitative agreement between the model output and experimental data was demonstrated, since very little information is currently available to guide the selection of parameter values for the models. This paper presents a model validating method using both multiple experimental data and global optimization

    The Confidential Inquiry into premature deaths of people with intellectual disabilities in the UK: a population-based study

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    SummaryBackgroundThe Confidential Inquiry into premature deaths of people with intellectual disabilities in England was commissioned to provide evidence about contributory factors to avoidable and premature deaths in this population.MethodsThe population-based Confidential Inquiry reviewed the deaths of people with intellectual disabilities aged 4 years and older who had been registered with a general practitioner in one of five Primary Care Trust areas of southwest England, who died between June 1, 2010, and May 31, 2012. A network of health, social-care, and voluntary-sector services; community contacts; and statutory agencies notified the Confidential Inquiry of all deaths of people with intellectual disabilities and provided core data. The Office for National Statistics provided data about the coding of individual cause of death certificates. Deaths were described as avoidable (preventable or amenable), according to Office for National Statistics definitions. Contributory factors to deaths were identified and quantified by the case investigator, verified by a local review panel meeting, and agreed by the Confidential Inquiry overview panel. Contributory factors were grouped into four domains: intrinsic to the individual, within the family and environment, care provision, and service provision. The deaths of a comparator group of people without intellectual disabilities but much the same in age, sex, and cause of death and registered at the same general practices as those with intellectual disabilities were also investigated.FindingsThe Confidential Inquiry reviewed the deaths of 247 people with intellectual disabilities. Nearly a quarter (22%, 54) of people with intellectual disabilities were younger than 50 years when they died, and the median age at death was 64 years (IQR 52ā€“75). The median age at death of male individuals with intellectual disabilities was 65 years (IQR 54ā€“76), 13 years younger than the median age at death of male individuals in the general population of England and Wales (78 years). The median age at death of female individuals with intellectual disabilities was 63 years (IQR 54ā€“75), 20 years younger than the median age at death for female individuals in the general population (83 years). Avoidable deaths from causes amenable to change by good quality health care were more common in people with intellectual disabilities (37%, 90 of 244) than in the general population of England and Wales (13%). Contributory factors to premature deaths in a subset of people with intellectual disabilities compared with a comparator group of people without intellectual disabilities included problems in advanced care planning (p=0Ā·0003), adherence to the Mental Capacity Act (p=0Ā·0008), living in inappropriate accommodation (p<0Ā·0001), adjusting care as needs changed (p=0Ā·009), and carers not feeling listened to (p=0Ā·006).InterpretationThe Confidential Inquiry provides evidence of the substantial contribution of factors relating to the provision of care and health services to the health disparities between people with and without intellectual disabilities. It is imperative to examine care and service provision for this population as potentially contributory factors to their deathsā€”factors that can largely be ameliorated.FundingDepartment of Health for England

    OPEs and 3-point correlators of protected operators in N=4 SYM

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    Two- and three-point correlation functions of arbitrary protected operators are constructed in N=4 SYM using analytic superspace methods. The OPEs of two chiral primary multiplets are given. It is shown that the nn-point functions of protected operators for nā‰¤4n\leq4 are invariant under U(1)YU(1)_Y and it is argued that this implies that the two- and three-point functions are not renormalised. It is shown explicitly how unprotected operators can be accommodated in the analytic superspace formalism in a way which is fully compatible with analyticity. Some new extremal correlators are exhibited

    Domestication, Genomics and the Future for Banana

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    Background Cultivated bananas and plantains are giant herbaceous plants within the genus Musa. They are both sterile and parthenocarpic so the fruit develops without seed. The cultivated hybrids and species are mostly triploid (2n = 3x = 33; a few are diploid or tetraploid), and most have been propagated from mutants found in the wild. With a production of 100 million tons annually, banana is a staple food across the Asian, African and American tropics, with the 15 % that is exported being important to many economies. Scope There are well over a thousand domesticated Musa cultivars and their genetic diversity is high, indicating multiple origins from different wild hybrids between two principle ancestral species. However, the difficulty of genetics and sterility of the crop has meant that the development of new varieties through hybridization, mutation or transformation was not very successful in the 20th century. Knowledge of structural and functional genomics and genes, reproductive physiology, cytogenetics, and comparative genomics with rice, Arabidopsis and other model species has increased our understanding of Musa and its diversity enormously. Conclusions There are major challenges to banana production from virulent diseases, abiotic stresses and new demands for sustainability, quality, transport and yield. Within the genepool of cultivars and wild species there are genetic resistances to many stresses. Genomic approaches are now rapidly advancing in Musa and have the prospect of helping enable banana to maintain and increase its importance as a staple food and cash crop through integration of genetical, evolutionary and structural data, allowing targeted breeding, transformation and efficient use of Musa biodiversity in the future

    Positive energy unitary irreducible representations of D=6 conformal supersymmetry

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    We give a constructive classification of the positive energy (lowest weight) unitary irreducible representations of the D=6 superconformal algebras osp(8*/2N). Our results confirm all but one of the conjectures of Minwalla (for N=1,2) on this classification. Our main tool is the explicit construction of the norms of the states that has to be checked for positivity. We give also the reduction of the exceptional UIRs.Comment: 27 pages, TeX with harvmac, amssym.def, amssym.tex; v.2: minor corrections and references added; v.3: minor corrections; v.4: to appear in J. Phys.

    Between tradition and modernity: Girls' talk about sexual relationships and violence in Kenya, Ghana and Mozambique

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    This paper interrogates the influence of a tradition-modernity dichotomy on perspectives and practices on sexual violence and sexual relationships involving girls in three districts of Kenya, Ghana and Mozambique. Through deploying an analytical framework of positioning within multiple discursive sites, we argue that although the dichotomy misrepresents the complexity of contemporary communities, it is nonetheless deployed by girls, educational initiatives, and researchers in their reflections on girlsā€™ sexual practices and sexual violence. The analysis examines variations between communities in patterns of and perspectives about sexual relationships, transactional sex and sexual violence. It illuminates ways in which features of ā€˜modernisationā€™ and ā€˜traditionā€™ both exacerbate and protect girls from violence. Across contexts, girls actively positioned themselves between tradition and modernity, while positioning others at the extreme poles. Education initiatives also invoked bipolar positions in their attempts to protect girlsā€™ rights to education and freedom from violence. The paper concludes by considering the implications for educational intervention and the potential for the analytical framing to generate richer, more contextualised understandings about girlsā€™ perspectives, experiences and ways of resisting sexual violence
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