49,210 research outputs found

    On the Solutions of Generalized Bogomolny Equations

    Full text link
    Generalized Bogomolny equations are encountered in the localization of the topological N=4 SYM theory. The boundary conditions for 't Hooft and surface operators are formulated by giving a model solution with some special singularity. In this note we consider the generalized Bogomolny equations on a half space and construct model solutions for the boundary 't Hooft and surface operators. It is shown that for the 't Hooft operator the equations reduce to the open Toda chain for arbitrary simple gauge group. For the surface operators the solutions of interest are rational solutions of a periodic non-abelian Toda system.Comment: 16 pages, no figure

    The controversy in the ÎłÎłâ†’ÏÏ\gamma\gamma\to\rho\rho process: potential scattering or qqqˉqˉqq\bar{q}\bar{q} resonance ?

    Full text link
    The ÎłÎłâ†’Ï0ρ0→4π\gamma\gamma\to\rho^0\rho^0\to 4 \pi reaction shows a broad peak at 1.5 GeV in the (JP,Jz)=(2+,2)(J^P,J_z)=(2^+,2) channel which has no counterpart in the ρ+ρ−\rho^+\rho^- channel. This "resonance" is considered as a candidate for a qqqˉqˉqq\bar q\bar q state in the "s-channel". We show, however, that it can also be explained by potential scattering of ρ0ρ0\rho^0\rho^0 via the σ\sigma- exchange in the "t-channel".Comment: 12 pages, latex, 3 postscript figures, to appear in Zeitschrift fur Physi

    Black Hole Entropy and the Dimensional Continuation of the Gauss-Bonnet Theorem

    Full text link
    The Euclidean black hole has topology ℜ2×Sd−2\Re^2 \times {\cal S}^{d-2}. It is shown that -in Einstein's theory- the deficit angle of a cusp at any point in ℜ2\Re^2 and the area of the Sd−2{\cal S}^{d-2} are canonical conjugates. The black hole entropy emerges as the Euler class of a small disk centered at the horizon multiplied by the area of the Sd−2{\cal S}^{d-2} there.These results are obtained through dimensional continuation of the Gauss-Bonnet theorem. The extension to the most general action yielding second order field equations for the metric in any spacetime dimension is given.Comment: 7 pages, RevTe

    Spectroscopic techniques and the conservation of artists’ acrylic emulsion paints

    Get PDF
    Artists’ acrylic emulsion paints are used in many contexts such as paintings, murals, sculptures, works on paper and mixed media; and are forming increasing proportions of modern and contemporary art collections. Although acrylic emulsion paints have been the focus of museum-led research over the past decade, the impact of artists’ technique and conservation treatment on the upper-most surface of these paints remains essentially unexplored ; This paper summarises previous studies using vibrational (FTIR) spectroscopy and presents initial assessments of paint surfaces using X-ray spectroscopies (XPS and NEXAFS) aimed at characterising artists’ acrylic paint film surfaces after natural ageing and wet surface cleaning treatment. Both techniques were found to be well suited for surface-sensitive investigations of the organic materials associated with artists’ acrylic paints, including explorations into: (A) cleaning system residues, (B) surfactant extraction from paint surfaces, (C) the identification of migrated surfactant, and (D) monitoring pigment changes at the paint/air interface of paint films ; It has been shown is that these X-ray spectroscopic techniques can be used for the analysis of almost purely organic materials in a way that complements mass spectroscopic techniques, FTIR and XRF. This investigation forms part of broader, currently ongoing, multi-technique investigation into the properties of artists’ acrylic paints and development of conservation treatments for works-of-art made with these materials

    Field performance of the parasitoid wasp, Trichogrammatoidea armigera (Hymenoptera: Trichogrammatidae) following releases against the millet head miner, Heliocheilus albipunctella (Lepidoptera: Noctuidae) in the Sahel

    Get PDF
    The effectiveness of the egg parasitoid Trichogrammatoidea armigera Nagaraja (Hymenoptera: Trichogrammatidae) in controlling Heliocheilus albipunctella de Joannis (Lepidoptera: Noctuidae), a major insect pest of pearl millet in the Sahel was assessed during two consecutive years in Niger on-station and on-farm conditions. We found that released T. armigera were able to find and parasitize host eggs within pearl millet fields both onstation and in farmers’ fields. On-station releases of T. armigera led to an average 4.86-fold increase in T. armigera parasitism compared to control fields, where no parasitoids were released. Likewise, on-farm releases of T. armigera led to up to 5.31-fold more egg parasitism by T. armigera in release fields than in control. Our results suggest the effectiveness of T. armigera and lays the groundwork for using T.armigera in augmentative biological control of H. albipunctella in the Sahel

    Determining the date of diagnosis – is it a simple matter? The impact of different approaches to dating diagnosis on estimates of delayed care for ovarian cancer in UK primary care

    Get PDF
    Background Studies of cancer incidence and early management will increasingly draw on routine electronic patient records. However, data may be incomplete or inaccurate. We developed a generalisable strategy for investigating presenting symptoms and delays in diagnosis using ovarian cancer as an example. Methods The General Practice Research Database was used to investigate the time between first report of symptom and diagnosis of 344 women diagnosed with ovarian cancer between 01/06/2002 and 31/05/2008. Effects of possible inaccuracies in dating of diagnosis on the frequencies and timing of the most commonly reported symptoms were investigated using four increasingly inclusive definitions of first diagnosis/suspicion: 1. "Definite diagnosis" 2. "Ambiguous diagnosis" 3. "First treatment or complication suggesting pre-existing diagnosis", 4 "First relevant test or referral". Results The most commonly coded symptoms before a definite diagnosis of ovarian cancer, were abdominal pain (41%), urogenital problems(25%), abdominal distension (24%), constipation/change in bowel habits (23%) with 70% of cases reporting at least one of these. The median time between first reporting each of these symptoms and diagnosis was 13, 21, 9.5 and 8.5 weeks respectively. 19% had a code for definitions 2 or 3 prior to definite diagnosis and 73% a code for 4. However, the proportion with symptoms and the delays were similar for all four definitions except 4, where the median delay was 8, 8, 3, 10 and 0 weeks respectively. Conclusion Symptoms recorded in the General Practice Research Database are similar to those reported in the literature, although their frequency is lower than in studies based on self-report. Generalisable strategies for exploring the impact of recording practice on date of diagnosis in electronic patient records are recommended, and studies which date diagnoses in GP records need to present sensitivity analyses based on investigation, referral and diagnosis data. Free text information may be essential in obtaining accurate estimates of incidence, and for accurate dating of diagnoses

    Exploring Protein-Protein Interactions as Drug Targets for Anti-cancer Therapy with In Silico Workflows

    Get PDF
    We describe a computational protocol to aid the design of small molecule and peptide drugs that target protein-protein interactions, particularly for anti-cancer therapy. To achieve this goal, we explore multiple strategies, including finding binding hot spots, incorporating chemical similarity and bioactivity data, and sampling similar binding sites from homologous protein complexes. We demonstrate how to combine existing interdisciplinary resources with examples of semi-automated workflows. Finally, we discuss several major problems, including the occurrence of drug-resistant mutations, drug promiscuity, and the design of dual-effect inhibitors.Fil: Goncearenco, Alexander. National Institutes of Health; Estados UnidosFil: Li, Minghui. Soochow University; China. National Institutes of Health; Estados UnidosFil: Simonetti, Franco Lucio. Consejo Nacional de Investigaciones CientĂ­ficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Parque Centenario. Instituto de Investigaciones BioquĂ­micas de Buenos Aires. FundaciĂłn Instituto Leloir. Instituto de Investigaciones BioquĂ­micas de Buenos Aires; ArgentinaFil: Shoemaker, Benjamin A. National Institutes of Health; Estados UnidosFil: Panchenko, Anna R. National Institutes of Health; Estados Unido

    Dynamics of localization in a waveguide

    Get PDF
    This is a review of the dynamics of wave propagation through a disordered N-mode waveguide in the localized regime. The basic quantities considered are the Wigner-Smith and single-mode delay times, plus the time-dependent power spectrum of a reflected pulse. The long-time dynamics is dominated by resonant transmission over length scales much larger than the localization length. The corresponding distribution of the Wigner-Smith delay times is the Laguerre ensemble of random-matrix theory. In the power spectrum the resonances show up as a 1/t^2 tail after N^2 scattering times. In the distribution of single-mode delay times the resonances introduce a dynamic coherent backscattering effect, that provides a way to distinguish localization from absorption.Comment: 18 pages including 8 figures; minor correction

    Modalites de consommation et valeur nutritionnelle des legumineuses alimentaires au Burkina Faso

    Get PDF
    Au Burkina Faso les lĂ©gumineuses constituent une source importante de nutriments pour les populations. La prĂ©sente Ă©tude a eu pour objectif de dĂ©terminer la valeur nutritionnelle et la place des lĂ©gumineuses dans le rĂ©gime alimentaire des mĂ©nages Ă  Ouagadougou, Kaya, Lebda et NobĂ©rĂ©. La mĂ©thodologie a consistĂ© en une enquĂȘte de consommation alimentaire auprĂšs de 325 mĂ©nages et Ă  dĂ©terminer les teneurs en macronutriments et en minĂ©raux fer, zinc et calcium de six (6) variĂ©tĂ©s de lĂ©gumineuses. Il en rĂ©sulte que les principales lĂ©gumineuses consommĂ©es dans les mĂ©nages sont l’arachide (Arachis hypogea L.), le niĂ©bĂ© (Vigna unguiculata L.), le voandzou (Vigna subterranea L.), le soja (Glycine max L.) et le zamnĂš (Acacia macrostachya R.). L’arachide, le niĂ©bĂ© et le voandzou sont consommĂ©es plus 2 Ă  4 fois dans le mois par l’ensemble des mĂ©nages sous forme de mets au sein des mĂ©nages tandis que le soja et le zamnĂš sont consommĂ©s hors mĂ©nage. A l’exception du voandzou qui est consommĂ© au dĂ©jeuner par 38,30% des mĂ©nages Ă  Ouagadougou, 60% Ă  Kaya, 66,67% Ă  Lebda et 43,18% Ă  NobĂ©rĂ©, les autres lĂ©gumineuses sont consommĂ©es Ă  tout moment de la journĂ©e par plus de 80 % des mĂ©nages enquĂȘtĂ©s. Les lĂ©gumineuses niĂ©bĂ©, voandzou et zamnĂš sont consommĂ©es sous forme de ragout et de plats associĂ©s Ă  des cĂ©rĂ©ales respectivement par 99%, 93% et 76%. L’arachide et le soja sont utilisĂ©s comme des ingrĂ©dients ou comme des collations. Les lĂ©gumineuses ont des teneurs importantes en protĂ©ines, 35,76%, 31,04%, 27,29%, 22,55% et 20,38% respectivement pour le zamnĂš, le soja, l’arachide, le niĂ©bĂ© et le voandzou. Les teneurs en lipides sont faibles et contribuent Ă  moins de 7% Ă  la valeur Ă©nergĂ©tique. Le niĂ©bĂ© et le voandzou ont des teneurs en carbohydrates Ă©levĂ©es, prĂšs de 60%. Les teneurs en fer des lĂ©gumineuses varient de 1,77 mg/100g (voandzou) Ă  6,50 mg/100g (soja). Celles en zinc varient de 5,34 mg/100 g (zamnĂš) Ă  4,33 mg/100g (soja). Le soja et le zamnĂš ont d’importantes teneurs en calcium, respectivement 57,42 mg/100g et 68,40 mg/100g. Du fait de leur valeur nutritionnelle intĂ©ressante en micronutriments ces deux lĂ©gumineuses nĂ©cessitent une attention particuliĂšre pour l’enrichissement des produits locaux. La diversification des produits issus de ces lĂ©gumineuses ainsi que celle des mĂ©thodes de consommation au sein des mĂ©nages permettront un meilleur profilage de leur bĂ©nĂ©fice nutritionnel auprĂšs des populations.Mots clĂ©s: LĂ©gumineuses, importance, consommation, mĂ©nages, nutriments, urbain, rural, Burkina Fas

    Development of the Carers’ Alert Thermometer (CAT) to identify family carers struggling with caring for someone dying at home: a mixed method consensus study

    Get PDF
    Background: There is an increasing international policy direction to promote home death for dying patients which will impact on the demands placed on family carers. The early identification of carer needs and appropriate intervention can help avoid crisis situations for the carer and avoidable hospital admissions which are reported to be a global concern. The aim of the study was to explore what professionals and carers of patients with cancer and advanced progressive illness, in their last year of life, find burdensome and to develop an alert system for use by non-specialist staff. Methods: A mixed-method, multi-phased, consensus study sequentially utilising qualitative and quantitative data to develop and pilot the Carers’ Alert Thermometer (CAT). 245 people (117 carers and 128 professionals) participated in the study across a range of health and social care settings in the North West of England (2011–2014). Results: A number of key domains were identified and prioritised by consensus for inclusion in the CAT. The 8 domains fit within two overarching themes of the reported carer experience; the support needed by the carer to provide care and the support needed for the carer’s own health and well-being. The resultant CAT is an evidence-based alert thermometer consisting of 10 questions, guidance on the possible actions for each alert and space for an action plan to be jointly agreed by the assessor and carer. Preliminary piloting of the CAT has shown it to be valued, fit for purpose and it can be administered by a range of personnel. Conclusions: The CAT enables the identification of current and potential future needs so a proactive approach can be taken to supporting the carer as their role develops over time, with a view to enhancing their well-being and preventing avoidable hospital admissions; ultimately supporting patient choice to remain in their own home
    • 

    corecore