5,491 research outputs found

    A Quantile Variant of the EM Algorithm and Its Applications to Parameter Estimation with Interval Data

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    The expectation-maximization (EM) algorithm is a powerful computational technique for finding the maximum likelihood estimates for parametric models when the data are not fully observed. The EM is best suited for situations where the expectation in each E-step and the maximization in each M-step are straightforward. A difficulty with the implementation of the EM algorithm is that each E-step requires the integration of the log-likelihood function in closed form. The explicit integration can be avoided by using what is known as the Monte Carlo EM (MCEM) algorithm. The MCEM uses a random sample to estimate the integral at each E-step. However, the problem with the MCEM is that it often converges to the integral quite slowly and the convergence behavior can also be unstable, which causes a computational burden. In this paper, we propose what we refer to as the quantile variant of the EM (QEM) algorithm. We prove that the proposed QEM method has an accuracy of O(1/K2)O(1/K^2) while the MCEM method has an accuracy of Op(1/K)O_p(1/\sqrt{K}). Thus, the proposed QEM method possesses faster and more stable convergence properties when compared with the MCEM algorithm. The improved performance is illustrated through the numerical studies. Several practical examples illustrating its use in interval-censored data problems are also provided

    On Teitelbaum type L-invariants of Hilbert Modular forms attached to definite quaternions

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    We generalize Teitelbaum's work on the definition of the L-invariant to Hilbert modular forms that arise from definite quaternion algebras over totally real fields by the Jacquet-Langlands correspondence. Conjecturally this coincides with the Fontaine-Mazur type L-invariant, defined by applying Fontaine's theory to the Galois representation associated to Hilbert modular forms. An exceptional zero conjecture for the p-adic L-function of Hilbert modular forms is also proposed. (C) 2014 Elsevier Inc. All rights reserved.X1111Ysciescopu

    TLR9 regulates adipose tissue inflammation and obesity-related metabolic disorders

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    ObjectiveRecent studies have revealed a link between Toll-like receptor (TLR) signaling and the adipose tissue inflammation associated with obesity. Although TLR9 is known to play an important role in inflammation and innate immunity, its role in mediating adipose tissue inflammation has not yet been investigated. Thus, the objective of this study was to determine the role of TLR9 in regulating immune cells in visceral adipose tissue and maintaining the metabolic homeostasis. MethodsWild-type and TLR9-deficient mice were fed with a high-fat diet, and the body weight gain, glucose tolerance, insulin sensitivity, and adipose tissue inflammation were examined. ResultsTLR9-deficient mice gained significantly more weight and body fat under a high-fat diet than wild-type mice and exhibited more severe glucose intolerance and insulin resistance. We also found a dramatic increase of M1 macrophages as well as T(H)1 cells in the adipose tissue of TLR9-deficient mice compared to wild-type mice. Furthermore, the levels of various proinflammatory cytokines and chemokines were higher in TLR9-deficient mice. ConclusionsTLR9 signaling is involved in regulating adipose tissue inflammation and controlling obesity and the metabolic syndrome.1174Ysciescopu

    The mu problem and sneutrino inflation

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    We consider sneutrino inflation and post-inflation cosmology in the singlet extension of the MSSM with approximate Peccei-Quinn(PQ) symmetry, assuming that supersymmetry breaking is mediated by gauge interaction. The PQ symmetry is broken by the intermediate-scale VEVs of two flaton fields, which are determined by the interplay between radiative flaton soft masses and higher order terms. Then, from the flaton VEVs, we obtain the correct mu term and the right-handed(RH) neutrino masses for see-saw mechanism. We show that the RH sneutrino with non-minimal gravity coupling drives inflation, thanks to the same flaton coupling giving rise to the RH neutrino mass. After inflation, extra vector-like states, that are responsible for the radiative breaking of the PQ symmetry, results in thermal inflation with the flaton field, solving the gravitino problem caused by high reheating temperature. Our model predicts the spectral index to be n_s\simeq 0.96 due to the additional efoldings from thermal inflation. We show that a right dark matter abundance comes from the gravitino of 100 keV mass and a successful baryogenesis is possible via Affleck-Dine leptogenesis.Comment: 27 pages, no figures, To appear in JHE

    Clinical decision support using Open Data

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    First Online: 18 May 2020.The growth of Electronical Health Records (EHR) in healthcare has been gradual. However, a simple EHR system has become inefficient in supporting health professionals on decision making. In this sense, the need to acquire knowledge from storing data using open models and techniques has emerged, for the sake of improving the quality of service provided and to support the decision-making process. The usage of open models promotes interoperability between systems, communicating more efficiently. In this sense, the OpenEHR open data approach is applied, modelling data in two levels to distinguish knowledge from information. The application of clinical terminologies was fundamental in this study, in order to control data semantics based on coded clinical terms. This article culminated from the conceptualization of the knowledge acquisition process to represent Clinical Decision Support, using open data models.The work has been supported by FCT–Fundação para a Ciência e Tec-nologia within the Project Scope UID/CEC/00319/2019 and DSAIPA/DS/0084/2018

    A phase II trial of ixabepilone in Asian patients with advanced gastric cancer previously treated with fluoropyrimidine-based chemotherapy

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    PURPOSE: The highest rates of gastric cancer occur in Eastern Asia. Fluoropyrimidine-based therapy is used initially in unresectable and metastatic disease, but no single standard of care exists following disease progression. Ixabepilone, an epothilone B analog, is a non-taxane microtubule-stabilizing agent with clinical activity across multiple tumor types approved by the United States Food and Drug Administration for treatment of metastatic breast cancer. METHODS: Asian patients with unresectable or metastatic gastric adenocarcinoma who had failed fluoropyrimidine-based chemotherapy received ixabepilone 40 mg/m(2) by 3-h intravenous infusion every 3 weeks. The primary endpoint was objective response rate (ORR). RESULTS: Fifty-two patients were treated (65.4 % men; median age: 56.5 years). The ORR was 15.4 % (95 % confidence interval [CI] 6.9-28.1); 8 patients achieved partial responses for a median duration of 3.1 months (95 % CI 2.6-4.1 months) and 26 patients (50.0 %) had stable disease. Median progression-free survival was 2.8 months (95 % CI 2.1-3.5 months). The most common grade 3 non-hematological toxicities were fatigue (9.6 %), decreased appetite (7.7 %), sensory neuropathy (5.8 %), and diarrhea (5.8 %). Grade 3/4 neutropenia occurred in 46.2 % of patients. CONCLUSIONS: Ixabepilone is active in Asian patients with advanced gastric cancer and shows a toxicity profile similar to those previously reported in other tumor types.published_or_final_versio

    Non-conformal Hydrodynamics in Einstein-dilaton Theory

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    In the Einestein-dilaton theory with a Liouville potential parameterized by η\eta, we find a Schwarzschild-type black hole solution. This black hole solution, whose asymptotic geometry is described by the warped metric, is thermodynamically stable only for 0η<20 \le \eta < 2. Applying the gauge/gravity duality, we find that the dual gauge theory represents a non-conformal thermal system with the equation of state depending on η\eta. After turning on the bulk vector fluctuations with and without a dilaton coupling, we calculate the charge diffusion constant, which indicates that the life time of the quasi normal mode decreases with η\eta. Interestingly, the vector fluctuation with the dilaton coupling shows that the DC conductivity increases with temperature, a feature commonly found in electrolytes.Comment: 27 pages and 2 figures, published in JHE
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