104 research outputs found

    AdS/QCD Phenomenological Models from a Back-Reacted Geometry

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    We construct a fully back-reacted holographic dual of a four-dimensional field theory which exhibits chiral symmetry breaking. Two possible models are considered by studying the effects of a five-dimensional field, dual to the qqˉq\bar{q} operator. One model has smooth geometry at all radii and the other dynamically generates a cutoff at finite radius. Both of these models satisfy Einstein's field equations. The second model has only three free parameters, as in QCD, and we show that this gives phenomenologically consistent results. We also discuss the possibility that in order to obtain linear confinement from a back-reacted model it may be necessary to consider the condensate of a dimension two operator.Comment: 13 pages, 4 figures, Replaced with minor correction

    Effect of the Interfacial Transition Zone on Basic Mechanical Properties of a Solid Composite Propellant

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    The evaluation of basic mechanical properties are shown to be of importance for the solid composite propellant development and application. The numerical analysis approach termed the three-phase Voronoi cell finite element method, was proposed to evaluate of the interfacial transition zone effect. Numerical results showed that the performance of the effective modulus could be essentially enhanced by increasing the zone thickness. The module of the composite with the inhomogeneous zone was higher than that of the composite with the homogeneous one. The effect of different zones on volume fractions and matrix moduli was also calculated. The Voronoi method can also be helpful for analyzing the characteristic properties of other three-phase composites.Определение основных механических характеристик играет важную роль в разработке и применении композитного твердого ракетного топлива. Предложен численный метод, получивший название “трехфазный метод конечных элементов ячейки Вороного”, для оценки влияния зоны межфазного перехода. Численные результаты показывают, что эффективный модуль можно улучшить, увеличив толщину зоны межфазного перехода. Модуль композита с неоднородной зоной межфазного перехода выше такового с однородной зоной межфазного перехода. Рассчитано влияние различных зон межфазного перехода на объемные доли и модули матрицы. Для анализа характеристических свойств других трехфазных композитов также можно использовать трехфазный метод конечных элементов ячейки Вороного

    Analysis of the vector form factors fKπ+(Q2)f^+_{K\pi}(Q^2) and fKπ(Q2)f^-_{K\pi}(Q^2) with light-cone QCD sum rules

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    In this article, we calculate the vector form factors fKπ+(Q2)f^+_{K\pi}(Q^2) and fKπ(Q2)f^-_{K\pi}(Q^2) within the framework of the light-cone QCD sum rules approach. The numerical values of the fKπ+(Q2)f^+_{K\pi}(Q^2) are compatible with the existing theoretical calculations, the central value of the fKπ+(0)f^+_{K\pi}(0), fKπ+(0)=0.97f^+_{K\pi}(0)=0.97, is in excellent agreement with the values from the chiral perturbation theory and lattice QCD. The values of the fKπ(0)|f^-_{K\pi}(0)| are very large comparing with the theoretical calculations and experimental data, and can not give any reliable predictions. At large momentum transfers with Q2>5GeV2Q^2> 5GeV^2, the form factors fKπ+(Q2)f^+_{K\pi}(Q^2) and fKπ(Q2)|f^-_{K\pi}(Q^2)| can either take up the asymptotic behavior of 1Q2\frac{1}{Q^2} or decrease more quickly than 1Q2\frac{1}{Q^2}, more experimental data are needed to select the ideal sum rules.Comment: 22 pages, 16 figures, revised version, to appear in Eur. Phys. J.

    Almost Maximal Lepton Mixing with Large T Violation in Neutrino Oscillations and Neutrinoless Double Beta Decay

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    We point out two simple but instructive possibilities to construct the charged lepton and neutrino mass matrices, from which the nearly bi-maximal neutrino mixing with large T violation can naturally emerge. The two lepton mixing scenarios are compatible very well with current experimental data on solar and atmospheric neutrino oscillations, and one of them may lead to an observable T-violating asymmetry between \nu_\mu --> \nu_e and \nu_e --> \nu_\mu transitions in the long-baseline neutrino oscillation experiments. Their implications on the neutrinoless double beta decay are also discussed.Comment: RevTex 15 pages (2 PS figures

    Wave functions and decay constants of BB and DD mesons in the relativistic potential model

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    With the decay constants of DD and DsD_s mesons measured in experiment recently, we revisit the study of the bound states of quark and antiquark in BB and DD mesons in the relativistic potential model. The relativistic bound state wave equation is solved numerically. The masses, decay constants and wave functions of BB and DD mesons are obtained. Both the masses and decay constants obtained here can be consistent with the experimental data. The wave functions can be used in the study of BB and DD meson decays.Comment: more discussion added, to appear in EPJ

    Rapid increase of scrub typhus incidence in Guangzhou, southern China, 2006-2014

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    Background: In the last decade, scrub typhus (ST) has been emerging or re-emerging in some areas of Asia, including Guangzhou, one of the most affected endemic areas of ST in China. Methods: Based on the data on all cases reported in Guangzhou from 2006 to 2014, we characterized the epidemiological features, and identified environmental determinants for the spatial distribution of ST using a panel negative binomial model. Results: A total of 4821 scrub typhus cases were reported in Guangzhou during 2006-2014. The annual incidence increased noticeably and the increase was relatively high and rapid in rural townships and among elderly females. The majority of cases (86.8%) occurred during May-October, and farmers constituted the majority of the cases, accounting for 33.9% in urban and 61.6% in rural areas. The number of housekeeper patients had a rapid increment in both rural and urban areas during the study period. Atmospheric pressure and relative humidity with lags of 1 or 2 months, distributions of broadleaved forest and rural township were identified as determinants for the spatiotemporal distribution of scrub typhus. Conclusion: Our results indicate that surveillance and public education need to be focused on the elderly farmers in rural areas covered with broadleaf forest in southern China

    Transformer-based biomarker prediction from colorectal cancer histology: A large-scale multicentric study.

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    Deep learning (DL) can accelerate the prediction of prognostic biomarkers from routine pathology slides in colorectal cancer (CRC). However, current approaches rely on convolutional neural networks (CNNs) and have mostly been validated on small patient cohorts. Here, we develop a new transformer-based pipeline for end-to-end biomarker prediction from pathology slides by combining a pre-trained transformer encoder with a transformer network for patch aggregation. Our transformer-based approach substantially improves the performance, generalizability, data efficiency, and interpretability as compared with current state-of-the-art algorithms. After training and evaluating on a large multicenter cohort of over 13,000 patients from 16 colorectal cancer cohorts, we achieve a sensitivity of 0.99 with a negative predictive value of over 0.99 for prediction of microsatellite instability (MSI) on surgical resection specimens. We demonstrate that resection specimen-only training reaches clinical-grade performance on endoscopic biopsy tissue, solving a long-standing diagnostic problem
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