5,126 research outputs found

    Degree correlation effect of bipartite network on personalized recommendation

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    In this paper, by introducing a new user similarity index base on the diffusion process, we propose a modified collaborative filtering (MCF) algorithm, which has remarkably higher accuracy than the standard collaborative filtering. In the proposed algorithm, the degree correlation between users and objects is taken into account and embedded into the similarity index by a tunable parameter. The numerical simulation on a benchmark data set shows that the algorithmic accuracy of the MCF, measured by the average ranking score, is further improved by 18.19% in the optimal case. In addition, two significant criteria of algorithmic performance, diversity and popularity, are also taken into account. Numerical results show that the presented algorithm can provide more diverse and less popular recommendations, for example, when the recommendation list contains 10 objects, the diversity, measured by the hamming distance, is improved by 21.90%.Comment: 9 pages, 3 figure

    Surgical techniques for early-stage thymoma: Video-assisted thoracoscopic thymectomy versus transsternal thymectomy

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    ObjectiveThe present study compared the outcomes between patients who had undergone video-assisted thoracoscopic surgery (VATS) thymectomy and transsternal (TS) thymectomy for Masaoka stage I and II thymoma.MethodsThe outcomes of 262 patients without myasthenia gravis who had undergone surgery for Masaoka stage I and II thymoma from January 2008 to December 2012 at our center were retrospectively evaluated. The study included 125 patients who had undergone unilateral VATS thymectomy (VATS group) and 137 patients who had undergone TS thymectomy (TS group).ResultsThe VATS group had a shorter operative time than the TS group (170 vs 210 minutes, P < .001). The VATS group also had a smaller intraoperative blood loss (200 vs 450 mL, P < .001), smaller pleural drainage volume in the first 24 hours postoperatively (300 vs 500 mL, P < .0010), shorter postoperative pleural drainage duration (3 vs 5 days, P < .001), and shorter postoperative hospital stay (8 vs 10 days, P < .001). Four patients in the VATS group underwent conversion to open surgery because of injury to the innominate vein. The postoperative complication rate was similar between the 2 groups. One patient in the VATS group developed pleural recurrence, and one in the TS group developed local recurrence.ConclusionsUnilateral VATS thymectomy for Masaoka stage I and II thymoma is technically feasible and safe and is less invasive than TS thymectomy, with a shorter duration of surgery, less intraoperative blood loss, less postoperative pleural drainage, shorter postoperative pleural drainage duration, and shorter postoperative hospital stay. We have concluded that it is preferable to perform VATS thymectomy, although perhaps under certain circumstances sternotomy might be preferred. The oncologic outcomes were comparable between the 2 procedures. Additional follow-up is required to evaluate the long-term outcomes

    The Protective Effect of Yi Shen Juan Bi Pill in Arthritic Rats with Castration-Induced Kidney Deficiency

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    Androgens have been linked to the onset, severity, and progression of rheumatoid arthritis (RA). In traditional Chinese medicine (TCM), the most common pattern in RA is kidney deficiency, which partly corresponds to a low sex hormone state. In this study, TCM kidney deficiency was induced in male Sprague-Dawley rats with castration surgery, and a TCM preparation, Yi Shen Juan Bi Pill (YJB), was used to treat collagen induced arthritis (CIA) rats with castration. Metabolomic technique was used to evaluate the pharmacological mechanism in castrated CIA rats treated by YJB. The results showed that castration significantly increased the severity of the arthritis in rats but was ameliorated by YJB. Its pharmacological mechanism was partially associated with lipid metabolites involving free fatty acid (FFA) and lysophosphatidylcholine (LPC). In conclusion, the experimental results demonstrate the protective effect of YJB on the TCM kidney deficiency pattern induced by androgen deficiency in CIA rats and support that YJB should be used for the clinical treatment of RA with TCM kidney deficiency pattern

    Application of light diffraction theory to qualify the downstream light field modulation property of mitigated KDP crystals

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    Micro-milling can effectively remove laser damage sites on a KDP (potassium dihydrogen phosphate) surface and then improve the laser damage resistance of the components. However, the repaired KDP surface could cause light propagating turbulence and downstream light intensification with the potential risk to damage downstream optics. In order to analyze the downstream light field modulation caused by Gaussian mitigation pits on KDP crystals, a computational model of the downstream light diffraction based on the angular spectrum theory and the Gaussian repair contour is established. The results show that the phase offset caused by the repaired surface produces a large light field modulation near the rear KDP surface. The modulation generated in the whole downstream light field is greater than that caused by the amplitude change. Therefore, the phase characteristics of the outgoing light could be suggested as a vital research topic for future research on the downstream light field modulation caused by mitigation contours. Significantly, the experimental results on the downstream light intensity distribution have good agreement with the simulation ones, which proves the validity of the established downstream light diffraction model. The phase characterization of the outgoing light is proposed as an evaluation tool in the repair of KDP crystals. The developed analytical method and numerical discrete algorithm could be also applicable in qualifying the repair quality of other optical components applied in high-power laser systems

    Tests of modified gravitational wave propagations with gravitational waves

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    Any violation of the fundamental principles of general relativity (GR), including the violations of the equivalence principle and parity/Lorentz symmetries, could induce possible derivations in the gravitational wave (GW) propagations so they can be tested/constrained directly by the GW data. In this letter, we present a universal parametrization for characterizing possible derivations from GW propagations in GR. This parametrization provides a general framework for exploring possible modified GW propagations arising from a large number of modified theories of gravity. With this parameterization, we construct the modified GW waveforms generated by the coalescence of compact binaries with the effects of the gravitational parity/Lorentz violations, then analyze the open data of compact binary merging events detected by LIGO/Virgo/KAGRA collaboration. We do not find any signatures of gravitational parity/Lorentz violations, thereby allowing us to place several of the most stringent constraints on parity/Lorentz violations in gravity and a first constraint on the Lorentz-violating damping effect in GW. This also represents the most comprehensive tests on the modified GW propagations.Comment: 6 pages, 3 tables, and 1 figur
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