3,415 research outputs found

    INDUSTRY STANDARDS USE AND ADAPTIVE KNOWLEDGE CREATION: A STUDY BASED ON INDUSTRY CONSORTIUM PERSPECTIVE

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    In order to facilitate the rapid development of B2B e-business and supply chain, many industry consortia develop industry-specific standards. This paper differentiates between two distinct dimensions characterizing organizations’ standards use: breadth and depth. We examine how industry consortia’ promotion strategies influence the breadth and depth of standards use, and how standards use influences adaptive knowledge creation. We also examine how firm size moderates the relationship between promotion strategies and standards use. The hypotheses are tested using survey data collected from organizations in China who have implemented RosettaNet standards. The empirical results show that relationship, policies, and technology strategies significantly affect standards use, and firm size moderates the influence. Further, only the depth of standards use influence adaptive knowledge creation

    VIS Standards Deployment and Integration: A Study of Antecedents and Benefits

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    Drawing on institutional theory and the literature on inter-organizational systems (IOS), this paper develops a research model for assessing the use of vertical information systems (VIS) standards. Extending prior research on IOS use, we differentiated between two distinct dimensions characterizing organizations’ use of VIS standards: the extent to which organizations adopt VIS standards across a wide range of business processes, and the extent of systems and business process integration. We examine how VIS standards deployment and integration differentially influence operational and strategic benefits that standards users obtain. We also examine how various institutional pressures (coercive, mimetic, and normative) influence the extent of deployment and integration of the VIS standards in different ways. The hypotheses are tested using survey data collected from organizations in Asia who have implemented RosettaNet standards

    There and Back Again: Revisiting Backpropagation Saliency Methods

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    Saliency methods seek to explain the predictions of a model by producing an importance map across each input sample. A popular class of such methods is based on backpropagating a signal and analyzing the resulting gradient. Despite much research on such methods, relatively little work has been done to clarify the differences between such methods as well as the desiderata of these techniques. Thus, there is a need for rigorously understanding the relationships between different methods as well as their failure modes. In this work, we conduct a thorough analysis of backpropagation-based saliency methods and propose a single framework under which several such methods can be unified. As a result of our study, we make three additional contributions. First, we use our framework to propose NormGrad, a novel saliency method based on the spatial contribution of gradients of convolutional weights. Second, we combine saliency maps at different layers to test the ability of saliency methods to extract complementary information at different network levels (e.g.~trading off spatial resolution and distinctiveness) and we explain why some methods fail at specific layers (e.g., Grad-CAM anywhere besides the last convolutional layer). Third, we introduce a class-sensitivity metric and a meta-learning inspired paradigm applicable to any saliency method for improving sensitivity to the output class being explained.Comment: CVPR 202

    Sterol biosynthesis is required for heat resistance but not extracellular survival in Leishmania

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    Sterol biosynthesis is a crucial pathway in eukaryotes leading to the production of cholesterol in animals and various C24-alkyl sterols (ergostane-based sterols) in fungi, plants, and trypanosomatid protozoa. Sterols are important membrane components and precursors for the synthesis of powerful bioactive molecules, including steroid hormones in mammals. Their functions in pathogenic protozoa are not well characterized, which limits the development of sterol synthesis inhibitors as drugs. Here we investigated the role of sterol C14α-demethylase (C14DM) in Leishmania parasites. C14DM is a cytochrome P450 enzyme and the primary target of azole drugs. In Leishmania, genetic or chemical inactivation of C14DM led to a complete loss of ergostane-based sterols and accumulation of 14-methylated sterols. Despite the drastic change in lipid composition, C14DM-null mutants (c14dm(-)) were surprisingly viable and replicative in culture. They did exhibit remarkable defects including increased membrane fluidity, failure to maintain detergent resistant membrane fraction, and hypersensitivity to heat stress. These c14dm(-) mutants showed severely reduced virulence in mice but were highly resistant to itraconazole and amphotericin B, two drugs targeting sterol synthesis. Our findings suggest that the accumulation of toxic sterol intermediates in c14dm(-) causes strong membrane perturbation and significant vulnerability to stress. The new knowledge may help improve the efficacy of current drugs against pathogenic protozoa by exploiting the fitness loss associated with drug resistance

    Image Projective Transformation Rectification with Synthetic Data for Smartphone-captured Chest X-ray Photos Classification

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    Classification on smartphone-captured chest X-ray (CXR) photos to detect pathologies is challenging due to the projective transformation caused by the non-ideal camera position. Recently, various rectification methods have been proposed for different photo rectification tasks such as document photos, license plate photos, etc. Unfortunately, we found that none of them is suitable for CXR photos, due to their specific transformation type, image appearance, annotation type, etc. In this paper, we propose an innovative deep learning-based Projective Transformation Rectification Network (PTRN) to automatically rectify CXR photos by predicting the projective transformation matrix. To the best of our knowledge, it is the first work to predict the projective transformation matrix as the learning goal for photo rectification. Additionally, to avoid the expensive collection of natural data, synthetic CXR photos are generated under the consideration of natural perturbations, extra screens, etc. We evaluate the proposed approach in the CheXphoto smartphone-captured CXR photos classification competition hosted by the Stanford University Machine Learning Group, our approach won first place with a huge performance improvement (ours 0.850, second-best 0.762, in AUC). A deeper study demonstrates that the use of PTRN successfully achieves the classification performance on the spatially transformed CXR photos to the same level as on the high-quality digital CXR images, indicating PTRN can eliminate all negative impacts of projective transformation on the CXR photos

    Serum fibroblast growth factor 21 is a superior biomarker to other adipokines in predicting incident diabetes

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    OBJECTIVE: Fibroblast growth factor 21 (FGF21) improves glucose and lipid metabolism, but high circulating levels are found in type 2 diabetes, suggesting FGF21 resistance. Serum FGF21 predicts incident diabetes, but its performance compared to established and emerging predictors is not known. We aimed to study the performance of FGF21 in diabetes prediction, relative to other adipokines and established risk factors including 2-h plasma glucose (2hG) during the oral glucose tolerance test (OGTT). DESIGN/PARTICIPANTS/MEASUREMENTS: We studied 1380 nondiabetic subjects from the Hong Kong Cardiovascular Risk Factor Prevalence Study using the second visit (2000-2004) as baseline when serum levels of FGF21 and other adipokines were measured. Glycaemic status was assessed by OGTT. Incident diabetes was defined as fasting glucose level (FG) ≥ 7 mmol/l or 2hG ≥ 11·1 mmol/l or use of antidiabetic agents, at subsequent visits. RESULTS: A total of 123 participants developed diabetes over 9·0 years (median). On multivariable logistic regression analysis, FGF21 (P = 0·003), adipocyte fatty acid-binding protein (P = 0·003) and adiponectin (P = 0·035) were independent predictors of incident diabetes. FGF21 had the best change in log likelihood when added to a diabetes prediction model (DP) based on age, family history, smoking, hypertension, BMI, dyslipidaemia and FG. It also improved the area under ROC curve (AUROC) of diabetes prediction (DP) from 0·797 to 0·819 (P = 0·0072), rendering its performance comparable to the 'DP + 2hG' model (AUROC=0·838, P = 0·19). CONCLUSIONS: As a biomarker for diabetes prediction, serum FGF21 appeared to be superior to other adipokines and, on its own, could be considered as an alternative to the OGTT. © 2016 John Wiley & Sons Ltd.postprin

    Sex‐specific activation of SK current by isoproterenol facilitates action potential triangulation and arrhythmogenesis in rabbit ventricles

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    Sex has a large influence on cardiac electrophysiological properties. Whether sex differences exist in apamin‐sensitive small conductance Ca2+‐activated K+ (SK) current (IKAS) remains unknown. We performed optical mapping, transmembrane potential, patch clamp, western blot and immunostaining in 62 normal rabbit ventricles, including 32 females and 30 males. IKAS blockade by apamin only minimally prolonged action potential (AP) duration (APD) in the basal condition for both sexes, but significantly prolonged APD in the presence of isoproterenol in females. Apamin prolonged APD at the level of 25% repolarization (APD25) more prominently than APD at the level of 80% repolarization (APD80), consequently reversing isoproterenol‐induced AP triangulation in females. In comparison, apamin prolonged APD to a significantly lesser extent in males and failed to restore the AP plateau during isoproterenol infusion. IKAS in males did not respond to the L‐type calcium current agonist BayK8644, but was amplified by the casein kinase 2 (CK2) inhibitor 4,5,6,7‐tetrabromobenzotriazole. In addition, whole‐cell outward IKAS densities in ventricular cardiomyocytes were significantly larger in females than in males. SK channel subtype 2 (SK2) protein expression was higher and the CK2/SK2 ratio was lower in females than in males. IKAS activation in females induced negative intracellular Ca2+–voltage coupling, promoted electromechanically discordant phase 2 repolarization alternans and facilitated ventricular fibrillation (VF). Apamin eliminated the negative Ca2+–voltage coupling, attenuated alternans and reduced VF inducibility, phase singularities and dominant frequencies in females, but not in males. We conclude that β‐adrenergic stimulation activates ventricular IKAS in females to a much greater extent than in males. IKAS activation plays an important role in ventricular arrhythmogenesis in females during sympathetic stimulation
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