5,126 research outputs found
Degree correlation effect of bipartite network on personalized recommendation
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
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
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
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
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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