1,921 research outputs found
Boundary Singularity for Thermal Transpiration Problem of the Linearized Boltzmann Equation
We study the boundary singularity of the fluid velocity for the thermal transpiration problem in the kinetic theory. Logarithmic singularity has been demonstrated through the asymptotic and computational analysis. The goal of this paper is to confirm this logarithmic singularity through exact analysis. We use an iterated scheme, with the “gain” part of the collision operator as a source. The iterated scheme is appropriate for large Knudsen numbers considered here and yields an explicit leading term
苦碟子联合低分子肝素钙治疗急性脑梗死疗效观察
Objective: to evaluate combinative effect of Kudiezi Injection and low molecular weight heparin calcium in the treatment of acute cerebral infarction. Methods: 72 cases of acute cerebral infarction were randomly divided into two groups, the treatment group of 36 cases were treated with the combination of Kudiezi Injection and low molecular heparin calcium; the other 36 cases in the control group were treated with the combination of Xuesaitong injection and low molecular weight heparin calcium. The degree of neurological deficit score and clinical outcome were respectively evaluated before and after treatment. Results: There are significant differences between the treatment group and the control group in results efficiency. Conclusion: It can improve the curative effect and the prognosis of the patients in the acute stage of cerebral infarction in the combinative treatment of Kudiezi Injection and low molecular weight heparin.目的 评价苦碟子注射液联合低分子肝素钙治疗急性脑梗死的临床效果及护理方法。方法 将72例急性脑梗死患者随机分为两组,治疗组36例用苦碟子联合低分子肝素钙治疗;对照组36例用血塞通注射液联合低分子肝素钙治疗。治疗前后分别进行神经功能缺损程度评分以及临床疗效评定[5]。结果 治疗组显效率与对照组比较差异有非常显著性(P=0.009)。结论 对急性期脑梗死患者在常规治疗基础上加用苦碟子及低分子肝素钙可显著提高疗效,改善患者预后。
Singularity of the Velocity Distribution Function in Molecular Velocity Space
We study the boundary singularity of the solutions to the Boltzmann equation in the kinetic theory. The solution has a jump discontinuity in the microscopic velocity ζ on the boundary and a secondary singularity of logarithmic type around the velocity tangential to the boundary, ζn∼0-, where ζn is the component of molecular velocity normal to the boundary, pointing to the gas. We demonstrate this secondary singularity by obtaining an asymptotic formula for the derivative of the solution on the boundary with respect to ζnn that diverges logarithmically when ζn∼0-. Our study is for the thermal transpiration problem between two plates for the hard sphere gases with sufficiently large Knudsen number and with the diffuse reflection boundary condition. The solution is constructed and its singularity is studied by an iteration procedure
Quality of life of Chinese urban community residents: a psychometric study of the mainland Chinese version of the WHOQOL-BREF
<p>Abstract</p> <p>Background</p> <p>The short version of the World Health Organization's Quality of Life Instrument (WHOQOL-BREF) is widely validated and popularly used in assessing the subjective quality of life (QOL) of patients and the general public. We examined its psychometric properties in a large sample of community residents in mainland China.</p> <p>Methods</p> <p>The WHOQOL-BREF was administered to 1052 adult community residents in a major metropolitan city in southern China. The structural integrity of the 4-factor model in confirmatory factor analyses (CFA) and the relationship of QOL with demographic variables were examined. Validity was assessed using the known-group comparison (229 with vs. 823 without chronic illness), item-domain correlations, and CFA using the ML estimation in LISREL.</p> <p>Results</p> <p>Internal consistency reliability of the whole instrument (26 items) was 0.89, and the psychological, social, and environment domains had acceptable reliability (alpha = 0.76, 0.72, 0.78 respectively), while that of the physical domain was slightly lower (α = 0.67). The respective mean scores of these domains were 13.69, 14.11, 12.33 and 14.56. Item-domain correlations were much higher for corresponding domains than for non-corresponding domains, indicating good convergent validity. CFA provided a marginally acceptable fit to the a priori four-factor model when two matching content item pairs were allowed to be correlated; χ<sup>2 </sup>(244) = 1836, RMSEA = 0.088, NNFI = 0.898, CFI = 0.909. This factorial structure was shown to be equivalent between the participants with and without chronic illness. The differences in means between these two groups were significant but small in some domains; effect size = 0.55, 0.15, 0.18 in the physical, psychological, and social relationship domains respectively. Furthermore, males had significantly higher QOL scores than females in the psychological domain, while individuals with a younger age, higher income, and higher education levels also had significantly higher QOL. Compared with the international data, the Chinese in this study had relatively low QOL scores with about 5% of males and 16% of females being at risk for poor QOL.</p> <p>Conclusions</p> <p>This study has provided psychometric properties of the WHOQOL-BREF as used in China and should definitely be useful for researchers who would like to use or further refine the instrument.</p
Can Variational Quantum Algorithms Demonstrate Quantum Advantages? Time Really Matters
Applying low-depth quantum neural networks (QNNs), variational quantum
algorithms (VQAs) are both promising and challenging in the noisy
intermediate-scale quantum (NISQ) era: Despite its remarkable progress,
criticisms on the efficiency and feasibility issues never stopped. However,
whether VQAs can demonstrate quantum advantages is still undetermined till now,
which will be investigated in this paper. First, we will prove that there
exists a dependency between the parameter number and the gradient-evaluation
cost when training QNNs. Noticing there is no such direct dependency when
training classical neural networks with the backpropagation algorithm, we argue
that such a dependency limits the scalability of VQAs. Second, we estimate the
time for running VQAs in ideal cases, i.e., without considering realistic
limitations like noise and reachability. We will show that the ideal time cost
easily reaches the order of a 1-year wall time. Third, by comparing with the
time cost using classical simulation of quantum circuits, we will show that
VQAs can only outperform the classical simulation case when the time cost
reaches the scaling of - years. Finally, based on the above
results, we argue that it would be difficult for VQAs to outperform classical
cases in view of time scaling, and therefore, demonstrate quantum advantages,
with the current workflow. Since VQAs as well as quantum computing are
developing rapidly, this work does not aim to deny the potential of VQAs. The
analysis in this paper provides directions for optimizing VQAs, and in the long
run, seeking more natural hybrid quantum-classical algorithms would be
meaningful.Comment: 18 pages, 7 figure
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Cognitive-enhancing effects of polygalasaponin hydrolysate in aβ(25-35)-induced amnesic mice.
Polygalasaponins are the major active constituents of Polygala tenuifolia exhibiting antiamnesic activity, but their applications are limited due to their toxicities. Evidence showed that the toxicities can be attenuated by hydrolysis. Herein, effects of a hydrolysate of polygalasaponins (HPS) on cognitive impairment induced by Aβ(25-35) were assessed by Morris water maze and step-through passive avoidance tests. The impaired spatial reference memory was improved by HPS (50 and 100 mg/kg). In the acquisition trial of step-through test, HPS (50 and 100 mg/kg) increased the latency into the dark chamber and decreased the error frequency significantly (P < .05). However, no significant change was observed during the retention trial. Additionally, HPS increased the corresponding SOD activities (62.34%, 22.09%) and decreased MDA levels (28.21%, 32.35%) in both cortex and hippocampus as compared to model animals. These results show that HPS may be a useful treatment against amnesia probably via its antioxidant properties.Peer Reviewe
Cognitive-enhancing effects of polygalasaponin hydrolysate in aβ(25-35)-induced amnesic mice.
Polygalasaponins are the major active constituents of Polygala tenuifolia exhibiting antiamnesic activity, but their applications are limited due to their toxicities. Evidence showed that the toxicities can be attenuated by hydrolysis. Herein, effects of a hydrolysate of polygalasaponins (HPS) on cognitive impairment induced by Aβ25−35 were assessed by Morris water maze and step-through passive avoidance tests. The impaired spatial reference memory was improved by HPS (50 and 100mg/kg). In the acquisition trial of step-through test, HPS (50 and 100mg/kg) increased the latency into the dark chamber and decreased the error frequency significantly (P < .05). However, no significant change was observed during the retention trial. Additionally, HPS increased the corresponding SOD activities (62.34%, 22.09%) and decreased MDA levels (28.21%, 32.35%) in both cortex and hippocampus as compared to model animals. These results show that HPS may be a useful treatment against amnesia probably via its antioxidant properties
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