897 research outputs found

    Efficient Correlated Topic Modeling with Topic Embedding

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    Correlated topic modeling has been limited to small model and problem sizes due to their high computational cost and poor scaling. In this paper, we propose a new model which learns compact topic embeddings and captures topic correlations through the closeness between the topic vectors. Our method enables efficient inference in the low-dimensional embedding space, reducing previous cubic or quadratic time complexity to linear w.r.t the topic size. We further speedup variational inference with a fast sampler to exploit sparsity of topic occurrence. Extensive experiments show that our approach is capable of handling model and data scales which are several orders of magnitude larger than existing correlation results, without sacrificing modeling quality by providing competitive or superior performance in document classification and retrieval.Comment: KDD 2017 oral. The first two authors contributed equall

    Hydrodynamic attraction of swimming microorganisms by surfaces

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    Cells swimming in confined environments are attracted by surfaces. We measure the steady-state distribution of smooth-swimming bacteria (Escherichia coli) between two glass plates. In agreement with earlier studies, we find a strong increase of the cell concentration at the boundaries. We demonstrate theoretically that hydrodynamic interactions of the swimming cells with solid surfaces lead to their re-orientation in the direction parallel to the surfaces, as well as their attraction by the closest wall. A model is derived for the steady-state distribution of swimming cells, which compares favorably with our measurements. We exploit our data to estimate the flagellar propulsive force in swimming E. coli

    A Role for CETP TaqIB Polymorphism in Determining Susceptibility to Atrial Fibrillation: A Nested Case Control Study

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    Studies investigating the genetic and environmental characteristics of atrial fibrillation (AF) may provide new insights in the complex development of AF. We aimed to investigate the association between several environmental factors and loci of candidate genes, which might be related to the presence of AF. A nested case-control study within the PREVEND cohort was conducted. Standard 12 lead electrocardiograms were recorded and AF was defined according to Minnesota codes. For every case, an age and gender matched control was selected from the same population (n = 194). In addition to logistic regression analyses, the multifactor-dimensionality reduction (MDR) method and interaction entropy graphs were used for the evaluation of gene-gene and gene-environment interactions. Polymorphisms in genes from the Renin-angiotensin, Bradykinin and CETP systems were included

    Product Yield and Fatty Acid Content of North Dakota Mule Deer, Elk, and Moose

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    The objective of this study was to determine and document proportion of edible lean from harvested big game species (mule deer, elk, and moose), analyze nutritive value of longissimus muscle (LM) tissue, and discuss the implications of shot damage on loss of edible lean. Twenty-nine mule deer (Odocoileus hemionus; MUL), 22 moose (Alces alces), and 21 elk (Cervus canadensis) were harvested from the field and processed at the North Dakota State University Meat Science Laboratory. Fatty acid analysis was conducted for each species. Field harvested animal yield data were collected and compared across species to include edible lean availability and tissue loss (trimming) associated with bullet damage (shot loss). Larger species had heavier whole body (WB), field dressed (FD), carcass (CARC), and lean (LN) yield, whereas the smaller species (MUL) had the highest FD expressed as a percentage of WB (77.19%). Shot loss expressed as a percentage of total lean tissue was greatest for elk (16.59%, P = 0.02), then MUL (13.24%), and moose (12.32%). The most edible lean (332.53 kg) was obtained from moose whereas MUL tended to yield more lean as a percentage of WB (42.07%, P = 0.06). Moose had the least crude fat on a DM basis, the least total kcals/100 g of loin sample, and least total cholesterol (mg/100 g of loin sample). Mule deer and elk exhibited a greater percentage of oleic acid (24.1 and 29.7%, respectively, expressed as a percentage of LM crude fat content) than moose (14.5%, P < 0.01). Mule deer had the highest stearic acid content (24.7%) compared to elk (12.83%) and moose (21.62%). This research found that elk and MUL have more desirable MUFA and SFA of total fat content than moose which possess the highest lean yield percentage

    ChaMPlane Optical Survey: Mosaic Photometry

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    The ChaMPlane survey to identify and analyze the serendipitous X-ray sources in deep Galactic plane fields incorporates the ChaMPlane Optical Survey, which is one of NOAO's Long-term Survey Programs. We started this optical imaging survey in March 2000 and completed it in June 2005. Using the NOAO 4-m telescopes with the Mosaic cameras at CTIO and KPNO, deep images of the ChaMPlane fields are obtained in V, R, I and H-alpha bands. This paper describes the process of observation, data reduction and analysis of fields included in the ChaMPlane Optical Survey, and describes the search for H-alpha emission objects and Chandra optical counterparts. We illustrate these procedures using the ChaMPlane field for the black hole X-ray binary GRO J0422+32 as an example.Comment: 14 pages, 10 figures, 7 tables, accepted in ApJ Supplement for publicatio

    Predictors of non-pharmacological intervention in patients with paroxysmal atrial fibrillation:Value of neuroticism

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    Background: Non-pharmacological intervention is gaining increasing popularity in the treatment of patients with paroxysmal atrial fibrillation. We sought to investigate which factors play a role in the choice for non-pharmacological intervention with a particular focus on neuroticism. Methods: The study group comprised 73 patients with paroxysmal atrial fibrillation (mean age 55 13 years, 50 males). On average, patients had a 3-year-history of one symptomatic paroxysm per week lasting 2 It. The degree of neuroticism was assessed using the short scale Eysenck Personality Questionnaire. Results: During a mean follow-up period of 7.0 +/- 0.6 years, 20 patients (27%) underwent a non-pharmacological intervention for atria] fibrillation including His bundle ablation (n=1), maze operation (n=4), DDDR-pacemaker (n=10), pulmonary vein ablation (n=5). Multivariate regression analysis showed that age <55 years (odds ratio 5.3, 95% CI 1.1-24.5), frequency of paroxysms of atrial fibrillation > 1 per week (odds ratio 5.9, 95% CI 1.2-28.5) and total number of anti-arrhythmic drugs (class I and III) used > 2 (odds ratio 3.4, 95% CI 1.6-6.9) were predictive of non-pharmacological intervention (all p <0.05). In contrast, the degree of neuroticism was similar in patients who underwent non-pharmacological intervention as opposed to patients who did not undergo non-pharmacological intervention (4.5 +/- 3.3 vs. 4.0 +/- 2.9, p = NS). Conclusions: On the basis of this small study, neuroticism would not appear to play an important role in the decision to perform a nonpharmacological intervention. Instead, the data indicate that younger patients with pharmacologically refractory atrial fibrillation more often undergo non-pharmacological intervention. (c) 2005 Elsevier Ireland Ltd. All rights reserved

    Towards a quality-controlled and accessible Pitzer model for seawater and related systems

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    We elaborate the need for a quality-controlled chemical speciation model for seawater and related natural waters, work which forms the major focus of SCOR Working Group 145. Model development is based on Pitzer equations for the seawater electrolyte and trace components. These equations can be used to calculate activities of dissolved ions and molecules and, in combination with thermodynamic equilibrium constants, chemical speciation. The major tasks to be addressed are ensuring internal consistency of the Pitzer model parameters (expressing the interactions between pairs and triplets of species, which ultimately determines the calculated activities), assessing uncertainties, and identifying important data gaps that should be addressed by new measurements. It is recognised that natural organic matter plays an important role in many aquatic ecosystems, and options for including this material in a Pitzer-based model are discussed. The process of model development begins with the core components which include the seawater electrolyte and the weak acids controlling pH. This core model can then be expanded by incorporating additional chemical components, changing the standard seawater composition and/or broadening the range of temperature and pressure, without compromising its validity. Seven important areas of application are identified: open ocean acidification; micro-nutrient biogeochemistry and geochemical tracers; micro-nutrient behaviour in laboratory studies; water quality in coastal and estuarine waters; cycling of nutrients and trace metals in pore waters; chemical equilibria in hydrothermal systems; brines and salt lakes

    HLA-DR expression on monocytes and systemic inflammation in patients with ruptured abdominal aortic aneurysms

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    INTRODUCTION: Mortality from ruptured abdominal aortic aneurysms (RAAA) remains high. Severe systemic inflammation, leading to multi-organ failure, often occurs in these patients. In this study we describe the level of HLA-DR expression in a consecutive group of patients following surgery for RAAA and compare results between survivors and non-survivors. A similar comparison is made for IL-6 and IL-10 levels and Sequential Organ Failure Assessment (SOFA) scores. METHODS: This is a prospective observational study. Patients with RAAA were prospectively analysed. Blood samples were collected on days 1, 3, 5, 7, 10 and 14. The fraction of CD-14 positive monocytes expressing HLA-DR was measured by flow-cytometry. IL-6 and IL-10 levels were measured by ELISA. RESULTS: The study included 30 patients with a median age of 70 years, of which 27 (90%) were men. Six patients died from multiple organ failure, all other patients survived. The SOFA scores were significantly higher in non-survivors on days 1 through 14. HLA-DR expression on monocytes was significantly lower on days 3, 5, 7, 10 and 14 in non-survivors. IL-6 and IL-10 levels were significantly higher in non-survivors on day 1 and days 1 and 3, respectively. CONCLUSION: HLA-DR expression on monocytes was decreased, especially in non-survivors. All patients with RAAA displayed a severe inflammatory and anti-inflammatory response with an increased production of IL-6 and IL-10. Poor outcome is associated with high levels of IL-6 and IL-10 and a high SOFA score in the first three days after surgery, while low levels of HLA-DR expression are observed from day three after RAAA repair

    An index for the Dirac operator on D3 branes with background fluxes

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    We study the problem of instanton generated superpotentials in Calabi-Yau orientifold compactifications directly in type IIB string theory. To this end, we derive the Dirac equation on a Euclidean D3 brane in the presence of background fluxes. We propose an index which governs whether the generation of a superpotential in the effective 4d theory by D3 brane instantons is possible. Applying the formalism to various classes of examples, including the K3 x T^2/Z_2 orientifold, in the absence and presence of fluxes, we show that our results are consistent with conclusions attainable via duality from an M-theory analysis.Comment: Fermion coupling to five-form restored, conclusions of the paper unchange
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