4,110 research outputs found

    A New Weibull-G Family of Distributions

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    Statistical analysis of lifetime data is an important topic in reliability engineering, biomedical and social sciences and others. We introduce a new generator based on the Weibull random variable called the new Weibull-G family. We study some of its mathematical properties. Its density function can be symmetrical, left-skewed, right-skewed, bathtub and reversed-J shaped, and has increasing, decreasing, bathtub, upside-down bathtub, J, reversed-J and S shaped hazard rates. Some special models are presented. We obtain explicit expressions for the ordinary and incomplete moments, quantile and generating functions, Renyi entropy, order statistics and reliability. Three useful characterizations based on truncated moments are also proposed for the new family. The method of maximum likelihood is used to estimate the model parameters. We illustrate the importance of the family by means of two applications to real data sets

    The Kumaraswamy Marshal-Olkin Family of Distributions

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    We introduce a new family of continuous distributions called the Kumaraswamy Marshal-Olkin generalized family of distributions. We study some mathematical properties of this family. Its density function is symmetrical, left-skewed, right-skewed and reversed-J shaped, and has constant, increasing, decreasing, upside-down bathtub, bathtub and S-shaped hazard rate. We present some special models and investigate the asymptotics and shapes of the family. We derive a power series for the quantile function and obtain explicit expressions for the moments, generating function, mean deviations, two types of entropies and order statistics. Some useful characterizations of the family are also proposed. The method of maximum likelihood is used to estimate the model parameters. We illustrate the importance of the family by means of two applications to real data sets

    Language learning strategies : a narrative literature review

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    Language Learning Strategies (LLS) are the steps or actions that a learner consciously takes to improve and regulate his or her language learning (Cohen & Macaro, 2009; Griffiths, 2013; Oxford, 2011). This chapter focuses on a narrative review of the use and effectiveness of LLS in second language learning (L2) contexts. This investigation provides teachers and researchers with a thorough understanding of LLS besides highlighting research gaps

    Plasma homocysteine, folate and vitamin B(12) compared between rural Gambian and UK adults.

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    The disease risk indicator plasma total homocysteine (tHcy) is influenced by genetic and environmental factors, including folate and vitamin B(12) status. Little is known about the determinants of tHcy in rural West Africa. We explored the hypothesis that tHcy in rural Gambian adults might vary between the sexes and physiological groups, and/or with folate and vitamin B(12) status. Comparisons were made with a British national survey. Non-pregnant Gambian women (n 158) had tHcy concentrations (geometric mean 9.0 micromol/l) similar to those of non-pregnant UK women (n 449; 9.4 micromol/l), whereas pregnant Gambian women (n 12) had significantly lower values (6.2 micromol/l). Gambian men (n 22) had significantly higher values (14.7 micromol/l) than British men (n 354; 10.8 micromol/l). Gambian lactating women and British men and women exhibited significant inverse relationships between log(e)(tHcy) and folate status; however, only the British subjects exhibited significant inverse relationships between loge(tHcy) and vitamin B(12) status. In the British sample, and in Gambian lactating women, folate and vitamin B(12) status variations together accounted for 20-25 % of the variation in log(e)(tHcy). Within the UK, black-skinned adults had folate and tHcy levels similar to those of their white-skinned counterparts, but significantly higher vitamin B(12) values. We conclude that, whereas folate and vitamin B(12) status are similar between British and rural Gambian populations, tHcy is higher in Gambian men and lower in pregnant Gambian women, and that serum vitamin B(12) values appear to be higher in black-skinned than white-skinned British subjects. Possible reasons are discussed

    CIDI-Lung-Seg: A Single-Click Annotation Tool for Automatic Delineation of Lungs from CT Scans

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    Accurate and fast extraction of lung volumes from computed tomography (CT) scans remains in a great demand in the clinical environment because the available methods fail to provide a generic solution due to wide anatomical variations of lungs and existence of pathologies. Manual annotation, current gold standard, is time consuming and often subject to human bias. On the other hand, current state-of-the-art fully automated lung segmentation methods fail to make their way into the clinical practice due to their inability to efficiently incorporate human input for handling misclassifications and praxis. This paper presents a lung annotation tool for CT images that is interactive, efficient, and robust. The proposed annotation tool produces an "as accurate as possible" initial annotation based on the fuzzy-connectedness image segmentation, followed by efficient manual fixation of the initial extraction if deemed necessary by the practitioner. To provide maximum flexibility to the users, our annotation tool is supported in three major operating systems (Windows, Linux, and the Mac OS X). The quantitative results comparing our free software with commercially available lung segmentation tools show higher degree of consistency and precision of our software with a considerable potential to enhance the performance of routine clinical tasks.Comment: 4 pages, 6 figures; to appear in the proceedings of 36th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC 2014

    Parameter Inference in the Pulmonary Circulation of Mice

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    This study focuses on parameter inference in a pulmonary blood cir- culation model for mice. It utilises a fluid dynamics network model that takes selected parameter values and aims to mimic features of the pulmonary haemody- namics under normal physiological and pathological conditions. This is of medical relevance as it allows monitoring of the progression of pulmonary hypertension. Constraint nonlinear optimization is successfully used to learn the parameter values

    ISOLATION OF EGG DROP SYNDROME VIRUS AND ITS MOLECULAR CHARACTERIZATION USING SODIUM DODECYL SULPHATE POLYACRYLAMIDE GEL ELECTROPHORESIS

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    Six isolates of egg drop syndrome (EDS) virus were recovered from five different outbreaks of EDS in commercial laying hens in and around Faisalabad. The aberrant eggs were fed to the susceptible laying hens for experimental induction of infection. The samples from infected birds (egg washing, cloacal swabs, oviducts and spleens) were collected, processed and inoculated into 11-day old duck embryos. The presence of virus in harvested allanto-amniotic fluid was monitored by spot and microhaemagglutination tests and confirmed by haemagglutination inhibition and agar gel precipitation tests. The EDS virus grew well in duck embryos and agglutinated only avian but not mammalian red blood cells. These isolates were purified through velocity density gradient centrifugation. Protein concentration was determined through Lowry method and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) was conducted by loading 300 µg protein concentration on 12.5% gel using discontinuous buffer system. All the six isolates showed 13 polypeptides, which were identical to those described in the referral EDS-76 virus (strain-127). The molecular weights of the polypeptides ranged from 6.5 KDa to 126 KDa

    MDR1 siRNA loaded hyaluronic acid-based CD44 targeted nanoparticle systems circumvent paclitaxel resistance in ovarian cancer.

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    Development of multidrug resistance (MDR) is an almost universal phenomenon in patients with ovarian cancer, and this severely limits the ultimate success of chemotherapy in the clinic. Overexpression of the MDR1 gene and corresponding P-glycoprotein (Pgp) is one of the best known MDR mechanisms. MDR1 siRNA based strategies were proposed to circumvent MDR, however, systemic, safe, and effective targeted delivery is still a major challenge. Cluster of differentiation 44 (CD44) targeted hyaluronic acid (HA) based nanoparticle has been shown to successfully deliver chemotherapy agents or siRNAs into tumor cells. The goal of this study is to evaluate the ability of HA-PEI/HA-PEG to deliver MDR1 siRNA and the efficacy of the combination of HA-PEI/HA-PEG/MDR1 siRNA with paclitaxel to suppress growth of ovarian cancer. We observed that HA-PEI/HA-PEG nanoparticles can efficiently deliver MDR1 siRNA into MDR ovarian cancer cells, resulting in down-regulation of MDR1 and Pgp expression. Administration of HA-PEI/HA-PEG/MDR1 siRNA nanoparticles followed by paclitaxel treatment induced a significant inhibitory effect on the tumor growth, decreased Pgp expression and increased apoptosis in MDR ovarian cancer mice model. Our findings suggest that CD44 targeted HA-PEI/HA-PEG/MDR1 siRNA nanoparticles can serve as a therapeutic tool with great potentials to circumvent MDR in ovarian cancer
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