528 research outputs found

    Trends in sexually transmitted infections in general practice 1990-2000: population based study using data from the UK general practice research database

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    Objective: To describe the contribution of primary care to the diagnosis and management of sexually transmitted infections in the United Kingdom, 1990-2000, in the context of increasing incidence of infections in genitourinary medicine clinics. Design: Population based study. Setting: UK primary care. Participants: Patients registered in the UK general practice research database. Main outcome measures: Incidence of diagnosed sexually transmitted infections in primary care and estimation of the proportion of major such infections diagnosed in primary care. Results: An estimated 23.0% of chlamydia cases in women but only 5.3% in men were diagnosed and treated in primary care during 1998-2000, along with 49.2% cases of non-specific urethritis and urethral discharge in men and 5.7% cases of gonorrhoea in women and 2.9% in men. Rates of diagnosis in primary care rose substantially in the late 1990s. Conclusions: A substantial and increasing number of sexually transmitted infections are diagnosed and treated in primary care in the United Kingdom, with sex ratios differing from those in genitourinary medicine clinics. Large numbers of men are treated in primary care for presumptive sexually transmitted infections

    Geometric tree kernels: Classification of COPD from airway tree geometry

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    Methodological contributions: This paper introduces a family of kernels for analyzing (anatomical) trees endowed with vector valued measurements made along the tree. While state-of-the-art graph and tree kernels use combinatorial tree/graph structure with discrete node and edge labels, the kernels presented in this paper can include geometric information such as branch shape, branch radius or other vector valued properties. In addition to being flexible in their ability to model different types of attributes, the presented kernels are computationally efficient and some of them can easily be computed for large datasets (N of the order 10.000) of trees with 30-600 branches. Combining the kernels with standard machine learning tools enables us to analyze the relation between disease and anatomical tree structure and geometry. Experimental results: The kernels are used to compare airway trees segmented from low-dose CT, endowed with branch shape descriptors and airway wall area percentage measurements made along the tree. Using kernelized hypothesis testing we show that the geometric airway trees are significantly differently distributed in patients with Chronic Obstructive Pulmonary Disease (COPD) than in healthy individuals. The geometric tree kernels also give a significant increase in the classification accuracy of COPD from geometric tree structure endowed with airway wall thickness measurements in comparison with state-of-the-art methods, giving further insight into the relationship between airway wall thickness and COPD. Software: Software for computing kernels and statistical tests is available at http://image.diku.dk/aasa/software.php.Comment: 12 page

    Semiparametric theory and empirical processes in causal inference

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    In this paper we review important aspects of semiparametric theory and empirical processes that arise in causal inference problems. We begin with a brief introduction to the general problem of causal inference, and go on to discuss estimation and inference for causal effects under semiparametric models, which allow parts of the data-generating process to be unrestricted if they are not of particular interest (i.e., nuisance functions). These models are very useful in causal problems because the outcome process is often complex and difficult to model, and there may only be information available about the treatment process (at best). Semiparametric theory gives a framework for benchmarking efficiency and constructing estimators in such settings. In the second part of the paper we discuss empirical process theory, which provides powerful tools for understanding the asymptotic behavior of semiparametric estimators that depend on flexible nonparametric estimators of nuisance functions. These tools are crucial for incorporating machine learning and other modern methods into causal inference analyses. We conclude by examining related extensions and future directions for work in semiparametric causal inference

    The PHENIX Experiment at RHIC

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    The physics emphases of the PHENIX collaboration and the design and current status of the PHENIX detector are discussed. The plan of the collaboration for making the most effective use of the available luminosity in the first years of RHIC operation is also presented.Comment: 5 pages, 1 figure. Further details of the PHENIX physics program available at http://www.rhic.bnl.gov/phenix

    A comparative view of glacial and periglacial landforms on Earth and Mars

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    This paper emphasizes the importance of using terrestrial analogues to improve our understanding of the role of ice on Mars through its associated landforms. We discuss terrestrial regions and techniques that can help understand Martian icy environments, and highlight the necessity to explore the Martian cryosphere as the next natural step

    Parental origin of sequence variants associated with complex diseases

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    To access publisher full text version of this article. Please click on the hyperlink in Additional Links fieldEffects of susceptibility variants may depend on from which parent they are inherited. Although many associations between sequence variants and human traits have been discovered through genome-wide associations, the impact of parental origin has largely been ignored. Here we show that for 38,167 Icelanders genotyped using single nucleotide polymorphism (SNP) chips, the parental origin of most alleles can be determined. For this we used a combination of genealogy and long-range phasing. We then focused on SNPs that associate with diseases and are within 500 kilobases of known imprinted genes. Seven independent SNP associations were examined. Five-one with breast cancer, one with basal-cell carcinoma and three with type 2 diabetes-have parental-origin-specific associations. These variants are located in two genomic regions, 11p15 and 7q32, each harbouring a cluster of imprinted genes. Furthermore, we observed a novel association between the SNP rs2334499 at 11p15 and type 2 diabetes. Here the allele that confers risk when paternally inherited is protective when maternally transmitted. We identified a differentially methylated CTCF-binding site at 11p15 and demonstrated correlation of rs2334499 with decreased methylation of that site.info:eu-repo/grantAgreement/EC/FP7/21807

    Determination of the Form Factors for the Decay B0 --> D*-l+nu_l and of the CKM Matrix Element |Vcb|

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    We present a combined measurement of the Cabibbo-Kobayashi-Maskawa matrix element Vcb|V_{cb}| and of the parameters ρ2\rho^2, R1R_1, and R2R_2, which fully characterize the form factors of the B0D+νB^0 \to D^{*-}\ell^{+}\nu_\ell decay in the framework of HQET, based on a sample of about 52,800 B0D+νB^0 \to D^{*-}\ell^{+}\nu_\ell decays recorded by the BABAR detector. The kinematical information of the fully reconstructed decay is used to extract the following values for the parameters (where the first errors are statistical and the second systematic): ρ2=1.156±0.094±0.028\rho^2 = 1.156 \pm 0.094 \pm 0.028, R1=1.329±0.131±0.044R_1 = 1.329 \pm 0.131 \pm 0.044, R2=0.859±0.077±0.022R_2 = 0.859 \pm 0.077 \pm 0.022, F(1)Vcb=(35.03±0.39±1.15)×103\mathcal{F}(1)|V_{cb}| = (35.03 \pm 0.39 \pm 1.15) \times 10^{-3}. By combining these measurements with the previous BABAR measurements of the form factors which employs a different technique on a partial sample of the data, we improve the statistical accuracy of the measurement, obtaining: ρ2=1.179±0.048±0.028,R1=1.417±0.061±0.044,R2=0.836±0.037±0.022,\rho^2 = 1.179 \pm 0.048 \pm 0.028, R_1 = 1.417 \pm 0.061 \pm 0.044, R_2 = 0.836 \pm 0.037 \pm 0.022, and F(1)Vcb=(34.68±0.32±1.15)×103. \mathcal{F}(1)|V_{cb}| = (34.68 \pm 0.32 \pm 1.15) \times 10^{-3}. Using the lattice calculations for the axial form factor F(1)\mathcal{F}(1), we extract Vcb=(37.74±0.35±1.25±1.441.23)×103|V_{cb}| =(37.74 \pm 0.35 \pm 1.25 \pm ^{1.23}_{1.44}) \times 10^{-3}, where the third error is due to the uncertainty in F(1)\mathcal{F}(1)

    Study of the Exclusive Initial-State Radiation Production of the DDˉD \bar D System

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    A study of exclusive production of the DDˉD \bar D system through initial-state r adiation is performed in a search for charmonium states, where D=D0D=D^0 or D+D^+. The D0D^0 mesons are reconstructed in the D0Kπ+D^0 \to K^- \pi^+, D0Kπ+π0D^0 \to K^- \pi^+ \pi^0, and D0Kπ+π+πD^0 \to K^- \pi^+ \pi^+ \pi^- decay modes. The D+D^+ is reconstructed through the D+Kπ+π+D^+ \to K^- \pi^+ \pi^+ decay mode. The analysis makes use of an integrated luminosity of 288.5 fb1^{-1} collected by the BaBar experiment. The DDˉD \bar D mass spectrum shows a clear ψ(3770)\psi(3770) signal. Further structures appear in the 3.9 and 4.1 GeV/c2c^2 regions. No evidence is found for Y(4260) decays to DDˉD \bar D, implying an up per limit \frac{\BR(Y(4260)\to D \bar D)}{\BR(Y(4260)\to J/\psi \pi^+ \pi^-)} < 7.6 (95 % confidence level)
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