216 research outputs found

    Massive Spinors and dS/CFT Correspondence

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    Using the map between free massless spinors on d+1 dimensional Minkowski spacetime and free massive spinors on dSd+1dS_{d+1}, we obtain the boundary term that should be added to the standard Dirac action for spinors in the dS/CFT correspondence. It is shown that this map can be extended only to theories with vertex ({\bar\p}\p)^2 but arbitrary d≥1d\ge1. In the case of scalar field theories such an extension can be made only for d=2,3,5d=2,3,5 with vertices ϕ6\phi^6, ϕ4\phi^4 and ϕ3\phi^3 respectively

    Note on generating functions and connected correlators of 1/2-BPS Wilson loops in N=4\mathcal{N}=4 SYM theory

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    The generating functions for the Wilson loops in the symmetric and antisymmetric representations of the gauge group U(N)U(N) are expressed in terms of the connected correlators of multiply-wound Wilson loops, using ingredients from the representation theory of the symmetric group. This provides a proof of a recent observation by Okuyama. As a by-product, we present a new calculation of the connected 2-point correlator of multiply-wound Wilson loops at leading order in 1/N1/N.Comment: 16 pages, v2: references added, changes in intro and conclusions, corrected typo

    Radiative corrections to W-boson hadroproduction: higher-order electroweak and supersymmetric effects

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    The high accuracy envisaged for future measurements of W-boson production at hadron colliders has to be matched by precise theoretical predictions. We study the impact of electroweak radiative corrections on W-boson production cross sections and differential distributions at the Tevatron and at the LHC. In particular, we include photon-induced processes, which contribute at O(alpha), and leading radiative corrections beyond O(alpha) in the high-energy Sudakov regime and from multi-photon final-state radiation. We furthermore present the calculation of the complete supersymmetric next-to-leading-order electroweak and QCD corrections to W-boson hadroproduction within the MSSM. The supersymmetric corrections turn out to be negligible in the vicinity of the W resonance in general, reaching the percent level only at high lepton transverse momentum and for specific choices of the supersymmetric parameters.Comment: 30 pages, 10 figures, 2 new sections, including a comparison with previous results on multi-photon radiation; version published in PR

    Complementary authentication of Chinese herbal products to treat endometriosis using DNA metabarcoding and HPTLC shows a high level of variability

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    Traditional Chinese Medicine (TCM) is popular for the treatment of endometriosis, a complex gynecological disease that affects 10% of women globally. The growing market for TCMs has yielded a significant incentive for product adulteration, and although emerging technologies show promise to improve their quality control, many challenges remain. We tested the authenticity of two traditional Chinese herbal formulae used in women’s healthcare for the treatment of endometriosis, known as Gui Zhi Fu Ling Wan (FL) and Ge Xia Zhu Yu Tang (GX). Dual-locus DNA metabarcoding analysis coupled with high-performance thin-layer chromatography (HPTLC) were used to authenticate 19 FL and six GX commercial herbal products, as well as three ad hoc prepared artificial mixtures. HPTLC was able to detect most of the expected ingredients via comparative component analysis. DNA metabarcoding was able to detect an unexpected species diversity in the products, including 38 unexpected taxa. Chromatography has a resolution for all species indirectly through the identification of marker compounds for the different species ingredients. Metabarcoding on the other hand yields an overview of species diversity in each sample, but interpretation of the results can be challenging. Detected species might not be present in quantities that matter, and without validated quantification, some detected species can be hard to interpret. Comparative analysis of the two analytical approaches also reveals that DNA for species might be absent or too fragmented to amplify as the relevant chemical marker compounds can be detected but no amplicons are assigned to the same species. Our study emphasizes that integrating DNA metabarcoding with phytochemical analysis brings valuable data for the comprehensive authentication of Traditional Chinese Medicines ensuring their quality and safe use

    Submillisievert Computed Tomography of the Chest Using Model-Based Iterative Algorithm: Optimization of Tube Voltage With Regard to Patient Size

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    Objective: The aim of this study was to define optimal tube potential for soft tissue and vessel visualization in dose-reduced chest CT protocols using model-based iterative algorithm in average and overweight patients. Methods: Thirty-six patients receiving chest CTaccording to 3 protocols (120 kVp/noise index [NI], 60;100 kVp/NI, 65;80 kVp/NI, 70) were included in this prospective study, approved by the ethics committee. Patients' physical parameters and dose descriptors were recorded. Images were reconstructed with model-based algorithm. Two radiologists evaluated image quality and lesion conspicuity;the protocols were intraindividually compared with preceding control CT reconstructed with statistical algorithm (120 kVp/NI, 20). Mean and standard deviation of attenuation of the muscle and fat tissues and signal-to-noise ratio of the aorta were measured. Results: Diagnostic images (lesion conspicuity, 95%-100%) were acquired in average and overweight patients at 1.34, 1.02, and 1.08 mGy and at 3.41, 3.20, and 2.88 mGy at 120, 100, and 80 kVp, respectively. Data are given as CT dose index volume values. Conclusions: Model-based algorithm allows for submillisievert chest CT in average patients;the use of 100 kVp is recommended

    Non-perturbative gauge superpotentials from supergravity

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    We study U(N) SQCD with N_f <= N flavors of quarks and antiquarks by engineering it with a configuration of fractional D3-branes on a C^3 / Z_2 x Z_2 orbifold. In particular we show how the moduli space of the gauge theory naturally emerges from the classical geometry produced by the D3-branes, and how the non-perturbatively generated superpotential is recovered from geometrical data.Comment: LaTeX, 18 pages, 4 figures; v2: published version with minor changes and an added referenc

    Analysis of the three-dimensional anatomical variance of the distal radius using 3D shape models

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    BACKGROUND: Various medical fields rely on detailed anatomical knowledge of the distal radius. Current studies are limited to two-dimensional analysis and biased by varying measurement locations. The aims were to 1) generate 3D shape models of the distal radius and investigate variations in the 3D shape, 2) generate and assess morphometrics in standardized cut planes, and 3) test the model's classification accuracy. METHODS: The local radiographic database was screened for CT-scans of intact radii. 1) The data sets were segmented and 3D surface models generated. Statistical 3D shape models were computed (overall, gender and side separate) and the 3D shape variation assessed by evaluating the number of modes. 2) Anatomical landmarks were assigned and used to define three standardized cross-sectional cut planes perpendicular to the main axis. Cut planes were generated for the mean shape models and each individual radius. For each cut plane, the following morphometric parameters were calculated and compared: maximum width and depth, perimeter and area. 3) The overall shape model was utilized to evaluate the predictive value (leave one out cross validation) for gender and side identification within the study population. RESULTS: Eighty-six radii (45 left, 44% female, 40 +/- 18 years) were included. 1) Overall, side and gender specific statistical 3D models were successfully generated. The first mode explained 37% of the overall variance. Left radii had a higher shape variance (number of modes: 20 female / 23 male) compared to right radii (number of modes: 6 female / 6 male). 2) Standardized cut planes could be defined using anatomical landmarks. All morphometric parameters decreased from distal to proximal. Male radii were larger than female radii with no significant side difference. 3) The overall shape model had a combined median classification probability for side and gender of 80%. CONCLUSIONS: Statistical 3D shape models of the distal radius can be generated using clinical CT-data sets. These models can be used to assess overall bone variance, define and analyze standardized cut-planes, and identify the gender of an unknown sample. These data highlight the potential of shape models to assess the 3D anatomy and anatomical variance of human bones

    Some Cubic Couplings in Type IIB Supergravity on AdS5×S5AdS_5\times S^5 and Three-point Functions in SYM_4 at Large N

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    All cubic couplings in type IIB supergravity on AdS5×S5AdS_5\times S^5 that involve two scalar fields sIs^I that are mixtures of the five form field strength on S5S^5 and the trace of the graviton on S5S^5 are derived by using the covariant equations of motion and the quadratic action for type IIB supergravity on AdS5×S5AdS_5\times S^5. All corresponding three-point functions in SYM4_4 are calculated in the supergravity approximation. It is pointed out that the scalars sIs^I correspond not to the chiral primary operators in the N=4{\cal N}=4 SYM but rather to a proper extension of the operators.Comment: Latex, 24p, misprints are correcte
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