173 research outputs found

    Dynamical mass generation in quantum field theory : some methods with application to the Gross-Neveu model and Yang-Mills theory

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    We introduce some techniques to investigate dynamical mass generation. The Gross-Neveu model (GN) is used as a toy model, because the GN mass gap is exactly known, making it possible to check reliability of the various methods. Very accurate results are obtained. Also application to SU(N) Yang-Mills (YM) is discussed.Comment: 8 LaTeX2e pages, uses Kluwer class file crckbked.cls. Kluwer package included. To appear in: Proceedings of the NATO Advanced Research Workshop on "Confinement, Topology, and other Non-Perturbative Aspects of QCD", Stara Lesna, Slovakia, 21-27 jan 200

    Zero Temperature Chiral Phase Transition in (2+1)-Dimensional QED with a Chern-Simons Term

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    We investigate the zero temperature chiral phase transition in (2+1)-dimensional QED in the presence of a Chern-Simons term, changing the number of fermion flavors. In the symmetric phase, there are no light degrees of freedom even at the critical point. Unlike the case without a Chern-Simons term, the phase transition is first-order.Comment: 7 pages, RevTeX, no figure

    Floating Hem-o-Lok Clips in the Bladder without Stone Formation after Robot-Assisted Laparoscopic Radical Prostatectomy

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    Hem-o-Lok clips (Weck Surgical Instruments, Teleflex Medical, Durham, NC, USA) are widely used in robot-assisted laparoscopic radical prostatectomy because of their easy application and secure clamping. To date, there have been some reports of intravesical migration of these clips causing urethral erosion, bladder neck contractures, and subsequent calculus formation. We report the first case of bladder migration of Hem-o-Lok clips without stone formation after robot-assisted laparoscopic radical prostatectomy. The Hem-o-Lok clips were found during urethral dilation with a guide wire for bladder neck contracture under cystourethroscopy. The Hem-o-Lok clips were floating in the bladder without stone formation and were removed by a cystoscopic procedure

    Discrete Anomaly and Dynamical Mass in 2+1 dimensional U(1)V×U(1)AU(1)_V\times U(1)_A Model

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    We note that in (2+1)-dimensional gauge theories with even number of massless fermions, there is anomalous Z2Z_2 symmetry if theory is regularized in a parity-invariant way. We then consider a parity invariant U(1)V×U(1)AU(1)_V\times U(1)_A model, which induces a mutual Chern-Simons term in the effective action due to Z2Z_2 anomaly. The effect of the discrete anomaly is studied in the induced spin and in the dynamical fermion mass.Comment: 14 pages, latex, two figures (available upon request

    Scoring Method for Early Prediction of Neonatal Chronic Lung Disease Using Modified Respiratory Parameters

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    In our previous study, we have demonstrated that peak inspiratory pressure over birth weight (PIP/kg) and mean airway pressure over birth weight (MAP/kg) were more significant risk factors for the development of neonatal chronic lung disease (CLD) than PIP and MAP. We aimed to develop a scoring method using the modified respiratory variables (SMUMRV) to predict CLD at early postnatal period. From 1997 to 1999, a retrospective review was performed for 197 infants <1,500 g for the development of the SMUMRV based on statistical analysis. From 2000 to 2001, calculated scores on day 4, 7 and 10 of life were obtained prospectively for 107 infants <1,500 g. Predictive values and the area under the receiver operator characteristic curve (AUC) were determined and compared with the result of the previous regression model. Gestational age, birth weight, 5 min Apgar score, PIP/kg at 12 hr of age, fractional inspired oxygen (FiO2), MAP/kg, modified oxygenation index and ventilatory mode were selected as parameters of SMUMRV. No significant differences of AUCs were found between the SMUMRV and the Yoder model. It is likely that our scoring method provides reliable values for predicting the development of CLD in very low birth weight infants

    Techni-dilaton as Dark Matter

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    We propose a new dark matter candidate, {\it light decoupled techni-dilaton}, which arises from the almost scale-invariant/conformal (walking) technicolor. We investigate its characteristic nature and discuss several cosmological and astrophysical constraints. It turns out that techni-dilatons are extremely weakly interacting and produced dominantly by the non-thermal mechanism to be the main component of dark matter with mass range between around 0.01 eV and 500 eV for typical walking technicolor scenarios.Comment: 6 pages, 2 figures; version to appear in PL

    General Gauge Mediation with Gauge Messengers

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    We generalize the General Gauge Mediation formalism to allow for the possibility of gauge messengers. Gauge messengers occur when charged matter fields of the susy-breaking sector have non-zero F-terms, which leads to tree-level, susy-breaking mass splittings in the gauge fields. A classic example is that SU(5) / SU(3) x SU(2) x U(1) gauge fields could be gauge messengers. We give a completely general, model independent, current-algebra based analysis of gauge messenger mediation of susy-breaking to the visible sector. Characteristic aspects of gauge messengers include enhanced contributions to gaugino masses, (tachyonic) sfermion mass-squareds generated already at one loop, and also at two loops, and significant one-loop A-terms, already at the messenger scale.Comment: 79 pages, 5 figure

    Development of Standard Digital Images for Pneumoconiosis

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    We developed the standard digital images (SDIs) to be used in the classification and recognition of pneumoconiosis. From July 3, 2006 through August 31, 2007, 531 retired male workers exposed to inorganic dust were examined by digital (DR) and analog radiography (AR) on the same day, after being approved by our institutional review board and obtaining informed consent from all participants. All images were twice classified according to the International Labour Office (ILO) 2000 guidelines with reference to ILO standard analog radiographs (SARs) by four chest radiologists. After consensus reading on 349 digital images matched with the first selected analog images, 120 digital images were selected as the SDIs that considered the distribution of pneumoconiosis findings. Images with profusion category 0/1, 1, 2, and 3 were 12, 50, 40, and 15, respectively, and a large opacity were in 43 images (A = 20, B = 22, C = 1). Among pleural abnormality, costophrenic angle obliteration, pleural plaque and thickening were in 11 (9.2%), 31 (25.8%), and 9 (7.5%) images, respectively. Twenty-one of 29 symbols were present except cp, ef, ho, id, me, pa, ra, and rp. A set of 120 SDIs had more various pneumoconiosis findings than ILO SARs that were developed from adequate methods. It can be used as digital reference images for the recognition and classification of pneumoconiosis

    Superconformal Flavor Simplified

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    A simple explanation of the flavor hierarchies can arise if matter fields interact with a conformal sector and different generations have different anomalous dimensions under the CFT. However, in the original study by Nelson and Strassler many supersymmetric models of this type were considered to be 'incalculable' because the R-charges were not sufficiently constrained by the superpotential. We point out that nearly all such models are calculable with the use of a-maximization. Utilizing this, we construct the simplest vector-like flavor models and discuss their viability. A significant constraint on these models comes from requiring that the visible gauge couplings remain perturbative throughout the conformal window needed to generate the hierarchies. However, we find that there is a small class of simple flavor models that can evade this bound.Comment: 43 pages, 1 figure; V3: small corrections and clarifications, references adde

    Texture classification of proteins using support vector machines and bio-inspired metaheuristics

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    6th International Joint Conference, BIOSTEC 2013, Barcelona, Spain, February 11-14, 2013[Abstract] In this paper, a novel classification method of two-dimensional polyacrylamide gel electrophoresis images is presented. Such a method uses textural features obtained by means of a feature selection process for whose implementation we compare Genetic Algorithms and Particle Swarm Optimization. Then, the selected features, among which the most decisive and representative ones appear to be those related to the second order co-occurrence matrix, are used as inputs for a Support Vector Machine. The accuracy of the proposed method is around 94 %, a statistically better performance than the classification based on the entire feature set. This classification step can be very useful for discarding over-segmented areas after a protein segmentation or identification process
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