Adjuvant chemotherapy for isolated resectable colorectal lung metastasis: A retrospective study using inverse probability treatment weighting propensity analysis

BACKGROUND The benefit of adjuvant chemotherapy(ACT)for patients with no evidence of disease after pulmonary metastasis resection(PM)from colorectal cancer(CRC)remains controversial.AIM To assess the efficacy of ACT in patients after PM resection for CRC.METHODS This study included 96 patients who underwent pulmonary metastasectomy for CRC at a single institution between April 2008 and July 2023.The primary end-point was overall survival(OS);secondary endpoints included cancer-specific survival(CSS)and disease-free survival(DFS).An inverse probability of treat-ment-weighting(IPTW)analysis was conducted to address indication bias.Sur-vival outcomes compared using Kaplan-Meier curves,log-rank test,Cox regre-ssion and confirmed by propensity score-matching(PSM).RESULTS With a median follow-up of 27.5 months(range,18.3-50.4 months),the 5-year OS,CSS and DFS were 72.0%,74.4%and 51.3%,respectively.ACT had no significant effect on OS after PM resection from CRC[original cohort:P=0.08;IPTW:P=0.15].No differences were observed for CSS(P=0.12)and DFS(P=0.68)between the ACT and non-ACT groups.Multivariate analysis showed no association of ACT with better survival,while sublobar resection(HR=0.45;95%CI:0.20-1.00,P=0.049)and longer disease-free interval(HR=0.45;95%CI:0.20-0.98,P=0.044)were associated with improved survival.CONCLUSION ACT does not improve survival after PM resection for CRC.Further well-designed randomized controlled trials are needed to determine the optimal ACT regimen and duration.

A weighted averaging method for signal probability of logic circuit combined with reconvergent fan-out structures

By analyzing the structures of circuits,a novel approach for signal probability estimation of very large-scale integration(VLSI)based on the improved weighted averaging algorithm(IWAA)is proposed.Considering the failure probability of the gate,first,the first reconvergent fan-ins corresponding to the reconvergent fan-outs were identified to locate the important signal correlation nodes based on the principle of homologous signal convergence.Secondly,the reconvergent fan-in nodes of the multiple reconverging structure in the circuit were identified by the sensitization path to determine the interference sources to the signal probability calculation.Then,the weighted signal probability was calculated by combining the weighted average approach to correct the signal probability.Finally,the reconvergent fan-out was quantified by the mixed-calculation strategy of signal probability to reduce the impact of multiple reconvergent fan-outs on the accuracy.Simulation results on ISCAS85 benchmarks circuits show that the proposed method has approximate linear time-space consumption with the increase in the number of the gate,and its accuracy is 4.2%higher than that of the IWAA.

HITTING PROBABILITIES OF WEIGHTED POISSON PROCESSES WITH DIFFERENT INTENSITIES AND THEIR SUBORDINATIONS

In this article,we study the hitting probabilities of weighted Poisson processes and their subordinated versions with different intensities.Furthermore,we simulate and analyze the asymptotic properties of the hitting probabilities in different weights and give an example in the case of subordination.

WEIGHTED APPROXIMATION OF RANDOM FUNCTIONS

Let (Ω, A, P) be a probability space, X(t, ω) a random function continuous in probability for t∈[0,+∞) or (-∞,+∞)(ω∈Ω), and F(t) a positive function continuous for t∈[0,+∞) or (-∞, +∞). If X(t, ω) and F(t) verify certain conditions, then there exists a sequence {Qn(t,ω)} of random polynomials such that we have almost surely: for t∈[0,+∞) or (-∞, +∞), lim|X(t, ω)-Qn(t, ω)|/F(t)=0.

Weighted Probability Density Estimator with Updated Bandwidths

In this paper,the authors study a class of weighted version of probability density estimator.It is shown that the weighted estimator contains some existing estimators of probability density,no matter they are recursive or non-recursive.Some statistical results including weak consistency,strong consistency,rate of strong consistency,and asymptotic normality are established under some mild conditions.Moreover,the random weighted estimator is also investigated.Some numerical simulations and a real data analysis are presented to study the numerical performances of the estimators.

A variable weight approach for evidential reasoning

A variable weight approach was proposed to handle the probability deficiency problem in the evidential reasoning （ER） approach. The probability deficiency problem indicated that the inadequate information in the assessment result should be less than that in the input. However, it was proved that under certain circumstances, the ER approach could not solve the probability deficiency problem. The variable weight approach was based on two assumptions： 1） the greater weight should be given to the rule with more adequate information; 2） the greater weight should be given to the rules with less disparate information. Assessment results of two notional case studies show that 1） the probability deficiency problem is solved using the proposed variable weight approach, and 2） the information with less inadequacy and more disparity is provided for the decision makers to help reach a consensus.

Most Probable Producing Ability of Bali Cows for Calving Interval and Calf Growth Performance

Most probable producing ability （MPPA） is the one factor used to compare the performance potential of dam based on the data of their progeny. The purpose of the research was to study the genetic ability of weaning weight, yearling weight and calving interval of Bali cows. The weaning weight data of 296 cows derived from 99 dams, yearling weight data of 245 cows derived from 86 dams and cabAng interval data of 194 cows from 63 dams were used to estimate repeatability and MPPA of Bali cows in a herd for the three traits. Repeatability of three traits was estimated by analysis of intra-class correlation, and these in turn were used for calculating the estimated MPPA of cows. The results showed that the means of weaning weight of males and females were 95.56 ± 17.25 kg and 87.57 ± 18.45 kg, respectively; means of yearling weight were 143.39 ±25.78 kg and 136.90 ± 22.01 kg, respectively; and mean calving interval was 391.62±22.59 d. The estimated repeatability of weaning weight, yearling weight and calving interval were 0.006 ±0.059, 0.022 ± 0.068 and 0.115 ± 0.078, respectively. The best 10 dams in the herd based on the estimates of MPPA for weaning weight, yearling weight and calving interval were not the same for the three traits.

Improvement of Bending Strength of Carbon Fiber/Thermoplastic Epoxy Composites <br/>—Effects of Molecular Weight of Epoxy on Carbon Fiber/Matrix Interfacial Strength and Connection of Cracks in Matrix

The bending strength of carbon?fiber/thermoplastic epoxy composites?(CF/TP-EP Compo.)?had?bi-linear increasewith increase of weight-average molecular weight (Mw) of matrix. The transition in the bending strength appeared at around 55k of Mw (“k”?means 103). SEM observation of fractured surface of CF/TP-EP Compo. showed that the fracture mode changed from interfacial failure to fiber breakage dominated failure. The smooth surface of carbon fibers appeared at lower Mw than 55k while some resin remained on the fibers indicating good adhesion between carbon fiber and matrix at higher Mw than 55k. The interfacial shear strength between carbon fiber and matrix bi-linearly increased with an increase of Mw similarly to the bending strength of the composite, measured by the micro droplet test. The dynamic loss tanδ?of the matrix measured at 2?Hz also showed a bi-linear relationship with respect to Mw having a knee point at Mw = 55k. The connection probability of two cracks introduced on?each side of specimens also confirmed that the interfacial strength between carbon fiber and matrix is the key for the mechanical performance of CF/TP-EP Compo. in bending.

区域地质灾害易发性评价的证据权法原理与实践

在阐述证据权法概念与原理的基础上,以西北黄土高原滑坡、崩塌地质灾害高易发的兰州市区为评价区,详解基于证据权法的区域地质灾害易发性评价的技术流程,利用GIS工具,开展评价指标选取与相关性分析、证据因子权重与后验概率分析、评价模型检验、易发程度评价。分析结果显示,坡度、坡向、地层岩性、断层、绿化灌溉、土地利用类型等地质灾害影响因素之间呈无相关或弱相关性,符合相互独立的要求,组成的模型ROC曲线(接受者操作特征曲线)AUC值(曲线下面积)为0.85,具有较高的预测精度。理论与实践表明,与其他统计学方法相比,证据权法同时考虑了评价指标中存在地质灾害与不存在地质灾害2种情况,避免了当地质灾害不存在时权重偏大导致结果失真的问题。证据权法结果为地质灾害发生的绝对概率,可以作为不同区域、地区的地质灾害易发程度对比的依据。

基于Relief算法的不平衡数据分类分级算法仿真

不平衡数据的分类分级是保证大数据技术高效使用过程中不可缺少的环节,但分类分级过程易受数据属性、冗余性、不均衡性等问题的干扰。为解决上述问题,提出不平衡数据朴素贝叶斯分类分级算法。采用合成少数类过采样技术降低数据的不平衡度,通过距离相关系数与最大信息系数完成不平衡数据的特征选择与筛选,采用Relief算法对筛选的特征做权重分配,并输入到朴素贝叶斯模型中实现分类,再结合动态阈值算法完成数据的分级。实验结果表明,所提算法的运行时间短、分类精度高,能够有效提升数据处理效果。

基于概率权重灰色马尔可夫模型的腐蚀预测

精准地预测管道的腐蚀发展趋势是降低油气事故损失,保证其安全运输的主要途径之一。针对常用的基于聚类中心灰色马尔可夫预测模型中等转移概率会导致较大预测误差的问题,提出了一种基于概率权重的灰色马尔可夫模型用于油气管道腐蚀预测。首先用灰色模型对管道腐蚀状态进行初步预测,后采用模糊C均值聚类对预测误差数据聚类,并提出基于概率权重的马尔可夫模型对预测值进行修正,以提高出现等转移概率时模型的预测精度。最后通过两个实例验证了上述模型的有效性和正确性,并与基于聚类中心灰色马尔可夫模型进行比较。

基于滑动窗口的协作频谱感知对抗拜占庭攻击

认知无线电技术允许从用户动态地接入主要用户被授权的频谱,提高频谱利用率。协作频谱感知是认知无线电技术的一个重要组成部分,通过空间分集检测主用户信号。然而,由于认知无线网络的开放性,协作频谱感知过程可能会受到拜占庭攻击,恶意用户伪造有关主用户信号的状态信息,然后对主用户的通信造成干扰或自私地占用频谱资源,此外,协作频谱感知因多个从用户协作而需要更多的时间来检测主用户信号,因而将导致协作频谱感知的性能和效率进一步降低。针对上述问题,提出了基于滑动窗口的协作频谱感知方案,以减轻拜占庭攻击的负面影响,提高协作效率。在深入分析融合中心盲的问题的基础上,从恶意用户的角度出发,建立了一个随机拜占庭攻击模型来描述恶意行为。为了解决感知样本融合过程中的盲的问题,提出了一种交付评估机制,为基于滑动窗口的协作频谱感知奠定了坚实的基础,并在一个滑动窗口内进一步评估信誉值,以提高报告阶段的协作效率。仿真结果表明,无论恶意比例如何,基于滑动窗口的协作频谱感知在始终攻击的情况下只需要6个平均样本数就可以提供100%的检测准确率,而在恶意比例超过50%的随机攻击的情况下依然能够展现出显著的性能优势。

多项式变异和自适应权重优化的阿奎拉鹰算法

针对基本阿奎拉鹰算法存在收敛精度低、易陷入局部最优的问题,通过在全局搜索阶段引入多项式变异扰动策略,在局部开发阶段引入自适应权重优化策略,改进了阿奎拉鹰算法的局部探索能力,并且引入了Tent混沌映射初始化种群,增加种群多样性,引入动态转换概率策略来平衡全局探索和局部开发的比重,故提出多项式变异和自适应权重优化的阿奎拉鹰算法。采用基本阿奎拉鹰算法、哈里斯鹰算法、灰狼算法、鲸鱼算法、海鸥算法做对比,9个基准测试函数和2个工程优化问题对改进后的算法进行寻优性能验证,结果表明:改进后的算法在多数测试函数上取得较好的寻优效果,在工程优化问题中,效果优于多数对比算法。证明了改进后的算法具有更快的收敛速度和精度,并在工程应用中取得较好效果。

Effectiveness of antibiotic prophylaxis for acute esophageal variceal bleeding in patients with band ligation: A large observational study

BACKGROUND Esophageal variceal bleeding is a severe complication associated with liver cirrhosis and typically necessitates endoscopic hemostasis.The current standard treatment is endoscopic variceal ligation(EVL),and Western guidelines recom-mend antibiotic prophylaxis following hemostasis.However,given the impro-vements in prognosis for variceal bleeding due to advancements in the management of bleeding and treatments of liver cirrhosis and the global concerns regarding the emergence of multidrug-resistant bacteria,there is a need to reassess the use of routine antibiotic prophylaxis after hemostasis.AIM To evaluate the effectiveness of antibiotic prophylaxis in patients treated for EVL.METHODS We conducted a 13-year observational study using the Tokushukai medical database across 46 hospitals.Patients were divided into the prophylaxis group(received antibiotics on admission or the next day)and the non-prophylaxis group(did not receive antibiotics within one day of admission).The primary outcome was composed of 6-wk mortality,4-wk rebleeding,and 4-wk spontaneous bacterial peritonitis(SBP).The secondary outcomes were each individual result and in-hospital mortality.A logistic regression with inverse probability of treatment weighting was used.A subgroup analysis was conducted based on the Child-Pugh classification to determine its influence on the primary outcome measures,while sensitivity analyses for antibiotic type and duration were also performed.RESULTS Among 980 patients,790 were included(prophylaxis:232,non-prophylaxis:558).Most patients were males under the age of 65 years with a median Child-Pugh score of 8.The composite primary outcomes occurred in 11.2%of patients in the prophylaxis group and 9.5%in the non-prophylaxis group.No significant differences in outcomes were observed between the groups(adjusted odds ratio,1.11;95%confidence interval,0.61-1.99;P=0.74).Individual outcomes such as 6-wk mortality,4-wk rebleeding,4-wk onset of SBP,and in-hospital mortality were not significantly different between the groups.The primary outcome did not differ between the Child-Pugh subgroups.Similar results were observed in the sensitivity analyses.CONCLUSION No significant benefit to antibiotic prophylaxis for esophageal variceal bleeding treated with EVL was detected in this study.Global reassessment of routine antibiotic prophylaxis is imperative.

基于倾向性评分逆概率加权法的视网膜母细胞瘤疗效评价及其预后影响因素分析

目的评估手术、化疗及手术联合化疗3种治疗方式对视网膜母细胞瘤(RB)的疗效,分析RB患者的预后影响因素。方法选取2000年1月1日-2019年12月31日美国监测、流行病学和最终结果(SEER)数据库登记的RB患者1188例临床资料进行回顾性分析。采用倾向性评分逆概率加权法(IPTW)对接受手术、化疗或手术联合化疗治疗的3组患者基线特征进行平衡。采用Log-rank检验比较3组患者的生存概率,采用Cox回归模型分析RB患者预后影响因素。结果共纳入RB1188例,其中手术组426例,化疗组200例,手术联合化疗组562例。经IPTW加权后,患者的年龄、性别、种族等基线资料均达到平衡(P>0.05)。Log-rank检验结果显示,加权前后3组生存曲线比较差异均有统计学意义(P<0.05);加权后,手术组患者生存情况明显优于化疗组和手术联合化疗组(P<0.05),化疗组与手术联合化疗组比较差异无统计学意义(P>0.05)。加权后患者1年、3年和5年的生存概率为:手术组99.7%、98.9%和98.6%;化疗组97.4%、95.8%和95.8%;手术联合化疗组97.9%、95.8%和95.0%。Cox回归分析结果显示,与手术组比较,化疗组患者特异性死亡风险比为1.367(95%CI 1.100~1.700),手术联合化疗组特异性死亡风险比为1.132(95%CI0.963~1.330);与RB病灶为1个的患者比较,RB病灶数≥2个的患者特异性死亡风险比为0.399(95%CI0.268~0.594)。结论RB患者接受治疗后生存概率较高;在控制年龄、性别等因素的影响后,3种治疗方式中手术的疗效更好;多灶性可能是RB患者预后的独立影响因素。

基于DSmT证据折扣理论的短波多通道信息融合方法

针对由于短波信道复杂恶劣、通道信息间冲突突出,经典合并方式对短波多通道信息合并效果不佳问题,提出基于DSmT证据折扣理论的短波多通道信息融合方法。以DSmT证据折扣理论作为融合框架,实现对短波多通道信息融合推理判决。首先,归一化OFDM帧的相对包络标准差,并通过相对包络标准差与折扣因子计算得到折扣权重。然后,通过比特软信息提取函数获得比特概率,以比特概率对基本信任分配函数定量赋值来作为证据。最后,以PCR6融合规则对多通道软信息进行融合推理判决。在多种信道条件、多种调制方式下与经典合并方式的对比仿真实验表明,所提方法可以获得明显的误码率增益和误包增益。

病毒感染与睡眠障碍之间的关联性——基于NHANES数据库的横断面研究

目的基于国家健康和营养检查调查(NHANES)数据库探讨多种病毒感染与睡眠障碍之间的关联性。方法选取NHANES数据库2009—2010年的横断面调查数据,根据睡眠障碍发生情况将研究对象分为睡眠障碍组与非睡眠障碍组。采用逆概率处理加权法(IPTW)平衡两组研究对象的基线特征。采用χ^(2)检验及标准均数差(SMD)评估IPTW分析前后两组基线特征的均衡性;应用非条件Logistic回归(IPTW分析前)和加权Logistic回归(IPTW分析后)分析7种病毒感染与睡眠障碍之间的关联性。针对HAV感染与睡眠障碍之间的关联性进行亚组分析。结果共纳入2385名研究对象,其中146名纳入睡眠障碍组,2239名纳入非睡眠障碍组。IPTW分析前,两组的年龄、人群、家庭收入贫困比率(PIR)、吸烟的SMD>0.1,基本特征不均衡;IPTW分析后,两组的基线特征差异无统计学意义(SMD<0.1,P>0.05),基本特征均衡。非条件Logistic回归结果显示,HAV感染、单纯疱疹病毒2型(HSV-2)感染与睡眠障碍存在相关性(P<0.05);加权Logistic回归结果显示,HSV-2感染者发生睡眠障碍的风险约为未感染者的1.93倍(P<0.05),而HAV感染与睡眠障碍无相关性(P>0.05)。亚组分析显示,HAV感染与睡眠障碍的关联性受年龄与教育水平等混杂因素显著影响(P交互作用<0.05)。结论经IPTW平衡基线特征后,HSV-2感染与睡眠障碍存在显著性关联。应对HSV-2感染者进行睡眠障碍情况筛查和干预,以提高该人群睡眠质量。

动态有权图上的随机游走概率计算

图上的随机游走概率计算是传统图论与现代数据挖掘领域普遍关注的问题之一.现有工作普遍关注静态图上的随机游走概率计算,却鲜少关注与实际应用场景更贴合的权重动态图.针对动态有权图上的随机游走概率计算问题,提出了一种基于硬币翻转采样的随机游走概率计算方法.相比于传统的基于权重采样的随机游走概率计算方法,所提方法可以在保证随机游走概率计算结果无偏的前提下,同时做到近似最优的随机游走概率计算复杂度和最优的采样结构更新复杂度.作为对比,现有方法或具有较大的计算时间复杂度,或依赖于复杂的索引结构而难以在动态图上即时更新.对所提方法做出了详细的理论分析,并在真实图数据集上进行模拟实验,实验结果证实了所提方法的有效性.

房间隔增厚率与心房颤动患者发生脑梗死概率呈现非线性的变化趋势:基于逆概率加权法

目的利用逆概率加权法探寻房间隔增厚率与心房颤动患者发生脑梗死的关系。方法选取2020年1月1日~2023年6月30日在南京中医药大学附属南京中医院(南京市中医院)就诊的标准心房颤动患者265例,将房间隔增厚率按照三分位数将患者分为第1组(0.01~0.089)、第2组(0.089~0.317)、第3组(0.317~0.690)。利用逆概率加权法均衡混杂因素后,调整组间差异。通过加权限制性立方样条曲线,研究房间隔增厚率与心房颤动患者发生脑梗死的变化趋势。结果逆概率加权法分析显示,房间隔增厚率第2组相对于第1组,心房颤动患者发生脑梗死的概率无明显变化(P=0.584),第3组相对于第1组概率下降86%(OR=0.144,95%CI:0.055~0.380,P<0.001)。加权限制性立方样条曲线分析显示,房间隔增厚率0.321为其临界值,心房颤动患者发生脑梗死的概率呈下降趋势。结论房间隔增厚率与心房颤动患者发生脑梗死概率呈现非线性的变化趋势。

中国共同富裕发展的时空演变特征及其影响因素

基于中国2011—2020年30个省份的面板数据,采用纵横向拉开档次法测算各省份的共同富裕发展水平,并探究共同富裕的空间马尔可夫状态转移概率,最后运用时空地理加权回归模型探究共同富裕发展的主要影响因素。结果表明:(1)2011—2020年我国共同富裕的发展水平呈上升态势,区域差异显著,东部的共同富裕发展水平最高,西部最低;(2)在考虑空间条件下,本省份共同富裕发展受相邻省份共同富裕发展影响而发生转移的概率各不相同,并且共同富裕的发展存在显著的时空惯性和路径依赖;(3)共同富裕发展水平的影响因素作用强度表现出明显的时空异质性,其中对外开放、数字金融水平和经济发展水平对共同富裕起促进作用,产业结构对共同富裕起抑制作用。最后,从区域差异和资源禀赋等方面提出相关建议。