带有二元连接函数的半参数模型

提出了一种新的带有二元连接函数的广义半参数模型,即二元连接模型(简称为BLM).使用轮廓似然方法估计模型的参数和非参数部分,并给出了计算算法.证明了所得的未知参数的估计量为n~(1/2)-相合,渐近正态且具有渐近最小方差,给出了实际数据分析和模拟研究,最终采用局部功效方法来检验非参数部分的线性性.     

右半结肠癌完全结肠系膜切除术清扫肠系膜根部淋巴结效果观察

目的 探讨右半结肠癌行完全结肠系膜切除术（CME）清扫肠系膜根部淋巴结的临床疗效。方法 以2010年12月 至2012 年12 月行CME 的57 例右半结肠癌患者作为观察组,同期接受传统结肠癌根治术的99 例右半结肠癌患者作为对照组,对两组患者的淋巴结清扫数量、平均出血量、手术时间、住院时间、术后排气、排便时间、手术并发症、2年局部复发率及生存率等情况进行比较,初步评价CME 清扫肠系膜根部淋巴结的临床效果。结果 CME 组与对照组总淋巴结清扫数量分别为（22.6±2.8）、（14.6±2.7）枚,CME 组淋巴结清扫数量明显多于对照组（P＜0.05）;CME 组平均出血量为（167.4±20.8）ml,对照组为（205.4±19.3）ml,CME 组出血量少于对照组（P＜0.05）;两组的手术时间、住院时间、术后排气、排便时间比较差异均无统计学意义（均P＞0.05）;CME 组手术并发症发生率与对照组比较差异无统计学意义（P ＞0.05）;Ⅲ期患者CME 组2 年局部复发率38.2％、生存率88.2％,对照组分别为64.8％和68.5％,两组差异有统计学意义（均P＜0.05）。结论 右半结肠癌患者采用CME 清扫肠系膜根部 淋巴结是安全和有效的。     

Positive numerical splitting method for the Hull and White 2D Black–Scholes equation

We consider the locally one‐dimensional backward Euler splitting method to solve numerically the Hull and White problem for pricing European options with stochastic volatility in the presence of a mixed derivative term. We prove the first‐order convergence of the time‐splitting. The parabolic equation degenerates on the boundary x = 0 and we apply a fitted finite volume scheme to the equation to resolve the degeneracy and derive the fully discrete problem as we also investigate the discrete maximum principle. Numerical experiments illustrate the efficiency of our difference scheme. © 2014 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 31: 822–846, 2015     

Prospective elementary teachers’ claiming in responses to false generalizations

When faced with a false generalization and a counterexample, what types of claims do prospective K-8 teachers make, and what factors influence the type and prudence of their claims relative to the data, observations, and arguments reported? This article addresses that question. Responses to refutation tasks and cognitive interviews were used to explore claiming. It was found that prospective K-8 teachers’ claiming can be influenced by knowledge of argumentation; knowledge and use of the mathematical practice of exception barring; perceptions of the task; use of natural language; knowledge of, use of, and skill with the mathematics register; and abilities to technically handle data or conceptual insights. A distinction between technical handlings for developing claims and technical handlings for supporting claims was made. It was found that prudent claims can arise from arguer-developed representations that afford conceptual insights, even when searching for support for a different claim.     

A novel liquid chromatographic method with fluorescence detection for quantitation of tadalafil and dapoxetine hydrochloride in pharmaceutical dosage form and human plasma北大核心CSCD

Tadalafil( TAD)and dapoxetine HCl( DAP)are recently co-formulated and both show native fluo-rescence. Therefore,a novel,accurate,specific and sensitive reversed-phase high performance liquid chroma-tographic method with fluorescence detection was developed and validated for their separation and quantitation in dosage form and human plasma using avanafil as an internal standard( IS). Separation was achieved using isocratic elution within 7. 0 min on C18 column and acetonitrile-0. 15% triethylamine( 40∶60,v/v;pH 4)as a mobile phase. The flow rate was 1. 0 mL/min and the detection was time-programmed at 330,410 and 370 nm for TAD,DAP and IS,respectively,after excitation at 236 nm. The linear ranges from 0. 01 to 30. 00 μg/mL for each drug with the limits of detection of 4. 20 and 7. 20 ng/mL for TAD and DAP,respectively. The method was validated in accordance to the International Conference on Harmonization( ICH)guidelines and was successful-ly applied to spiked human plasma with mean recoveries of 98. 17% and 98. 83% for TAD and DAP respectively.     

Resonant equations with the Neumann p-Laplacian plus an indefinite potential

We consider a nonlinear Neumann problem driven by the p  -Laplacian plus an indefinite potential and a Carathéodory reaction which at ±∞ is resonant with respect to any nonprincipal variational eigenvalue of the differential operator. Using critical point theory and Morse theory (critical groups), we show that the problem has at least three nontrivial smooth solutions, two of which have constant sign. In the process we prove some results of independent interest concerning the unique continuation property of eigenfunctions and the critical groups at infinity of a C¹$C^1$-functionals.     

基于Chebyshev多项式的神经网络中长期负荷预测研究

高精度负荷预测在提高电力系统的安全性和经济性方面有着极其重要的意义,而现有的负荷预测方法因参数有限,难以完全反映其内在规律,因而导致预测结果不够准确.为此提出了一种基于Chebyshev多项式神经网络模型的预测方法.该方法使用递推最小二乘法训练神经网络权值系数,以获得高精度的参数估计,从而实现Chebyshev多项式神经网络模型对负荷量的最优拟合,再利用训练好的Chebyshev多项式神经网络模型实现中长期负荷预测.研究结果表明,该方法能较好模拟负荷变化规律,有效提高了负荷预测精度,在电力系统负荷预测中有较大的应用价值.     

The Order of Automorphisms of Quasigroups

We prove quadratic upper bounds on the order of any autotopism of a quasigroup or Latin square, and hence also on the order of any automorphism of a Steiner triple system or 1‐factorization of a complete graph. A corollary is that a permutation σ chosen uniformly at random from the symmetric group will almost surely not be an automorphism of a Steiner triple system of order n, a quasigroup of order n or a 1‐factorization of the complete graph . Nor will σ be one component of an autotopism for any Latin square of order n. For groups of order n it is known that automorphisms must have order less than n, but we show that quasigroups of order n can have automorphisms of order greater than n. The smallest such quasigroup has order 7034. We also show that quasigroups of prime order can possess autotopisms that consist of three permutations with different cycle structures. Our results answer three questions originally posed by D.  Stones.     

环状硅酸盐图的友好指数集

Let G be a graph with vertex set V(G) and edge set E(G). A labeling f : V(G) →Z2 induces an edge labeling f*: E(G) → Z2 defined by f*(xy) = f(x) + f(y), for each edge xy ∈ E(G). For i ∈ Z2, let vf(i) = |{v ∈ V(G) : f(v) = i}| and ef(i) = |{e ∈ E(G) : f*(e) =i}|. A labeling f of a graph G is said to be friendly if |vf(0)- vf(1)| ≤ 1. The friendly index set of the graph G, denoted FI(G), is defined as {|ef(0)- ef(1)|: the vertex labeling f is friendly}. This is a generalization of graph cordiality. We investigate the friendly index sets of cyclic silicates CS(n, m).