81 research outputs found

    Towards Accurate One-Stage Object Detection with AP-Loss

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    One-stage object detectors are trained by optimizing classification-loss and localization-loss simultaneously, with the former suffering much from extreme foreground-background class imbalance issue due to the large number of anchors. This paper alleviates this issue by proposing a novel framework to replace the classification task in one-stage detectors with a ranking task, and adopting the Average-Precision loss (AP-loss) for the ranking problem. Due to its non-differentiability and non-convexity, the AP-loss cannot be optimized directly. For this purpose, we develop a novel optimization algorithm, which seamlessly combines the error-driven update scheme in perceptron learning and backpropagation algorithm in deep networks. We verify good convergence property of the proposed algorithm theoretically and empirically. Experimental results demonstrate notable performance improvement in state-of-the-art one-stage detectors based on AP-loss over different kinds of classification-losses on various benchmarks, without changing the network architectures. Code is available at https://github.com/cccorn/AP-loss.Comment: 13 pages, 7 figures, 4 tables, main paper + supplementary material, accepted to CVPR 201

    Effect of bedtime administration of blood-pressure lowering agents on ambulatory blood pressure monitoring results: A meta-analysis

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    Background: Bedtime administration of antihypertensive drugs currently receives more at­tention, but no clear consensus has been reached on the blood pressure (BP)-lowering effect of this strategy. Methods: We systematically searched literature for clinical trials of ingestion time of anti­hypertensive drugs evaluated by ambulatory blood pressure monitoring (ABPM) to perform a meta-analysis which aimed at determining the difference in diurnal, nocturnal, and 24-h mean of systolic BP (SBP) and diastolic BP (DBP), absolute BP reduction from baseline between bedtime administration group (experimental group) and morning (awaking) administration group (control group). Results: The synthesis analysis showed that the level of BP in bedtime administration group was lower than the morning administration group, which reduced diurnal SBP/DBP by 1.67/1.13 mm Hg (p = 0.36/0.48), 24-h SBP/DBP by 2.78/0.36 mm Hg (p = 0.09/0.62), nocturnal SBP/DBP by 6.32/3.17 mm Hg (p = 0.03/0.007). Furthermore, there was lack of statistically significant differences in the diurnal mean of SBP/DBP reduction from baseline between the two groups (p = 0.94/0.85), but bedtime administration resulted in significant reduction from baseline in the nocturnal mean of SBP/DBP, by –4.72/–3.57 mm Hg (p = 0.01/0.05). Funnel plot demonstrated that there was no evidence of publication bias. Conclusions: Administration of ≥ 1 antihypertensive drugs at bedtime or evening results in a greater reduction of nocturnal hypertension than dosing in the morning without loss of efficacy of diurnal and 24 h mean BP reduction

    novoPathFinder: a webserver of designing novel-pathway with integrating GEM-model

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    To increase the number of value-added chemicals that can be produced by metabolic engineering and synthetic biology, constructing metabolic space with novel reactions/pathways is crucial. However, with the large number of reactions that existed in the metabolic space and complicated metabolisms within hosts, identifying novel pathways linking two molecules or heterologous pathways when engineering a host to produce a target molecule is an arduous task. Hence, we built a user-friendly web server, novoPathFinder, which has several features: (i) enumerate novel pathways between two specified molecules without considering hosts; (ii) construct heterologous pathways with known or putative reactions for producing target molecule within Escherichia coli or yeast without giving precursor; (iii) estimate novel pathways with considering several categories, including enzyme promiscuity, Synthetic Complex Score (SCScore) and LD50 of intermediates, overall stoichiometric conversions, pathway length, theoretical yields and thermodynamic feasibility. According to the results, novoPathFinder is more capable to recover experimentally validated pathways when comparing other rule-based web server tools. Besides, more efficient pathways with novel reactions could also be retrieved for further experimental exploration. novoPathFinder is available at http://design.rxnfinder.org/novopathfinder/

    A Fast Decline of Residual Renal Function in the First Year is a Predictor for Early Withdrawal from Peritoneal Dialysis in Non-Diabetic Patients

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    Background/Aims: Little is known about the relationship between residual renal function (RRF) decline in early period and survival in non-diabetic peritoneal dialysis (PD) patients. Methods: A total of 567 non-diabetic patients who began PD from January 1, 2005 to June 30, 2013 was investigated. The rate of RRF decline was determined by the “slope of the trend equation” of serial RRFs. A composite end-point of all-cause mortality and conversion to hemodialysis (HD) was used, survival status was censored on June 30, 2016. Results: The median of “the slope of RRF decline equation” was 0.308 (0.001-2.111) ml/min/1.73 m2/ month. In the median follow-up period of 43 months (range 12 to 120 months), 65 (11.5%) patients died, 90 (15.9%) patients converted to HD and 171 (30.2%) patients received kidney transplantation. Multivariate linear regression showed male, high baseline RRF, high baseline peritoneal Kt/V urea, low serum albumin and low uric acid were independently associated with the rate of RRF decline in the first year of PD. Multivariate Cox models revealed that RRF decline in the first year remained a predictor for composite end-point (HR, 2.74, 95% CI, 1.53 to 4.90, P=0.001). The patients were divided into high RRF decline group (> 0.308ml/ min/1.73m2/month) and low RRF decline group (≤0.308 ml/min/1.73m2/month). In the first three years of PD, the rate of end-point events was higher in high RRF decline group (23.2%) than that in low RRF decline group (11.0%) (P< 0.001). There were 189 patients in low RRF decline group and 171 patients in high RRF decline group maintaining PD for more than 3 years, in a median follow-up of 54 months (range 37 to 120 months), the survival rate was 30.9% in high RRF decline group and 46.4% in low RRF decline group (P=0.883). In high RRF decline group, there were 92 patients reaching composited end-point and 112 patients maintaining PD; multivariate Cox model showed high peritoneal Kt/V urea after 1 year of PD and high albumin level were protective factors (HR, 0.29, 95% CI, 0.13 to 0.61, P= 0.001; HR, 0.94, 95% CI, 0.90-0.99, P=0.022, respectively), while fast RRF decline remained risk factor for composite end-point (HR, 3.28, 95% CI,1.48-7.31, P=0.004). Conclusion: A faster RRF decline in the first year was a predictor for all-cause mortality and conversion to HD in non-diabetic PD patients, mainly in the first three year. For patients with faster RRF decline, increasing PD dose was effective to improve survival

    R&D capabilities, intellectual property strength and choice of equity ownership in cross-border acquisitions: Evidence from BRICS acquirers in Europe

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    YesThe aim of the study is to investigate two relatively underexplored factors, namely, the R&D (research and development) capabilities of target firms and the strength of intellectual property (IP) institutions in target economies, that influences the choice of equity ownership in cross border acquisitions (CBAs) undertaken by multinational enterprises (MNEs) from BRICS (Brazil, Russia, India, China and South Africa) economies. We develop our key hypothesis on foreign market entry through CBAs by incorporating insights from transaction costs economics, the resource-based view and institutional theory to investigate the determinants of full versus partial equity ownership. Using logistic regression estimation methods to a sample of 111 CBA deals of BRICS MNEs in 22 European countries, we find that BRICS MNEs are likely to pursue full rather than partial acquisition mode when target firms have high R&D capabilities. However, the greater the degree of strength of IP institutions in target economies and higher the target firms’ R&D capabilities, the more likely it is for BRICS MNEs to undertake partial, rather than, full acquisition mode. We provide interesting theoretical insights and managerial implications that might underlie some of the key findings on CBAs by emerging market MNEs

    Equity ownership in cross-border mergers and acquisitions by British firms: an analysis of real options and transaction cost factors

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    The authors investigate the factors influencing the share of equity ownership sought in cross-border mergers and acquisitions (CBM&As). Drawing on real options theory and transaction cost economics (TCE), they address and hypothesize key factors linked to commitment under exogenous uncertainty and the separation of desired and non-desired assets’ influence on share of equity sought by acquiring firms in CBM&As. Empirical analysis based on 1872 CBM&As undertaken by British firms in both developed and emerging economies shows that British MNEs are more likely to pursue a partial acquisition in a target foreign firm when those foreign firms are from culturally distant countries. Further, findings support the view that the high cost of separating desired assets from non-desired assets motivates firms to make a partial acquisition rather than acquire the target completely. This is one of the first studies to use real options theory to address the cost of commitment under exogenous uncertainty, as well as TCE logic to address the separation of desired and non-desired assets in the target firm while analysing equity ownership sought in CBM&As. Empirically, this paper contributes by examining CBM&As by British firms in both developed and emerging markets

    Integration of Non-market and Market Activities in Cross-border Mergers and Acquisitions

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    Drawing on the resource dependence theory and the resource-based view, this paper investigates the interactions between market and nonmarket activities of firms in the context of the post-merger integration phase in cross-border mergers and acquisitions (M&As). Based on a cross-country survey of 111 M&A practitioners who were personally involved in cross-border M&As around the world, we test seven hypotheses on various market and nonmarket aspects of post-merger integration. We find a positive correlation between buffering strategies and adaptive capabilities in the nonmarket environment, and between bridging and adaptive capabilities in the market environment. However, we could not find any significant correlation between buffering and adaptive capabilities in the market environment, and bridging and adaptive capabilities in the nonmarket environment. We also find that adaptability in the nonmarket environment is positively correlated with adaptability in the market environment, and in turn adaptability in the market environment leads to positive organizational performance of a cross border M&A. These results provide further support for the value of the alignment between market and nonmarket activities and help to fill a gap in the literature on the market-nonmarket interactions in post-merger integration

    Sustainable supply chain management towards disruption and organizational ambidexterity:A data driven analysis

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    Balancing sustainability and disruption of supply chains requires organizational ambidexterity. Sustainable supply chains prioritize efficiency and economies of scale and may not have sufficient redundancy to withstand disruptive events. There is a developing body of literature that attempts to reconcile these two aspects. This study gives a data-driven literature review of sustainable supply chain management trends toward ambidexterity and disruption. The critical review reveals temporal trends and geographic distribution of literature. A hybrid of data-driven analysis approach based on content and bibliometric analyses, fuzzy Delphi method, entropy weight method, and fuzzy decision-making trial and evaluation laboratory is used on 273 keywords and 22 indicators obtained based on the experts’ evaluation. The most important indicators are identified as supply chain agility, supply chain coordination, supply chain finance, supply chain flexibility, supply chain resilience, and sustainability. The regions show different tendencies compared with others. Asia and Oceania, Latin America and the Caribbean, and Africa are the regions needs improvement, while Europe and North America show distinct apprehensions on supply chain network design. The main contribution of this review is the identification of the knowledge frontier, which then leads to a discussion of prospects for future studies and practical industry implementation
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