Positive definiteness of real quadratic forms resulting from the variable-step L1-type approximations of convolution operators

The positive definiteness of real quadratic forms with convolution structures plays an important rolein stability analysis for time-stepping schemes for nonlocal operators. In this work, we present a novel analysistool to handle discrete convolution kernels resulting from variable-step approximations for convolution operators.More precisely, for a class of discrete convolution kernels relevant to variable-step L1-type time discretizations, weshow that the associated quadratic form is positive definite under some easy-to-check algebraic conditions. Ourproof is based on an elementary constructing strategy by using the properties of discrete orthogonal convolutionkernels and discrete complementary convolution kernels. To our knowledge, this is the first general result onsimple algebraic conditions for the positive definiteness of variable-step discrete convolution kernels. Using theunified theory, we obtain the stability for some simple nonuniform time-stepping schemes straightforwardly.

A MODIFIED BFGS FORMULA MAINTAINING POSITIVE DEFINITENESS WITH ARMIJO-GOLDSTEIN STEPLENGTHS

The line search subproblem in unconstrained optimization is concerned with finding an acceptable steplength satisfying certain standard conditions. The con-ditions proposed in the early work of Armijo and Goldstein are sometimes replaced by those recommended by Wolf e because these latter conditions automatically allow positive definiteness of some popular quasi-Newton updates to be maintained.It is shown that a slightly modified form of quasi-Newton update allows positive definiteness to be maintained even if line searches based on the Armijo-Goldsteinconditions are used.

Effectiveness and safety of combined nimotuzumab and S-1 chemotherapy with concurrent radiotherapy for locally advanced esophageal cancer in malnourished and elderly patients:A prospective phaseⅡstudy

Objective:Definitive chemoradiotherapy(dCRT)is the standard treatment for unresectable locally advanced esophageal cancer.However,this treatment is associated with substantial toxicity,and most malnourished or elderly patients are unable to complete this therapy.Therefore,there is a need for a more suitable radiotherapy combination regimen for this population.This study was aimed to evaluate the efficacy and safety of a combination regimen comprising chemotherapy with nimotuzumab and S-1 and concurrent radiotherapy for patients with fragile locally advanced esophageal cancer with a high Nutritional Risk Screening 2002(NRS-2002)score.Methods:Eligible patients with unresectable esophageal carcinoma who had an NRS-2002 score of 2 or higher were enrolled.They were treated with S-1 and nimotuzumab with concurrent radiotherapy,followed by surgery or definitive radiotherapy.The primary endpoint was the locoregional control(LRC)rate.Results:A total of 55 patients who met the study criteria were enrolled.After completion of treatment,surgery was performed in 15 patients and radiotherapy was continued in 40 patients.The median follow-up period was 33.3[95%confidence interval(95%CI,31.4−35.1)]months.The LRC rate was 77.2%(95%CI,66.6%−89.4%)at 1 year in the entire population.The overall survival(OS)rate and event-free survival(EFS)rate were 57.5%and 51.5%at 3 years,respectively.Surgery was associated with better LRC[hazard ratio(HR)=0.16;95%CI,0.04−0.70;P=0.015],OS(HR=0.19;95%CI,0.04−0.80;P=0.024),and EFS(HR=0.25;95%CI,0.08−0.75;P=0.013).Most adverse events were of grade 1 or 2,and no severe adverse events occurred.Conclusions:For malnourished or elderly patients with locally advanced esophageal cancer,radiotherapy combined with nimotuzumab and S-1 is effective and has a good safety profile.

Comparative efficacy and safety between endoscopic submucosal dissection,surgery and definitive chemoradiotherapy in patients with cT1N0M0 esophageal cancer

BACKGROUND Endoscopic submucosal dissection(ESD)and surgical resection are the standard of care for cT1N0M0 esophageal cancer(EC),whereas definitive chemoradiotherapy(d-CRT)is a treatment option.Nevertheless,the comparative efficiency and safety of ESD,surgery and d-CRT for cT1N0M0 EC remain unclear.AIM To compare the efficiency and safety of ESD,surgery and d-CRT for cT1N0M0 EC.METHODS We retrospectively analyzed the hospitalized data of a total of 472 consecutive patients with cT1N0M0 EC treated at Sun Yat-sen University Cancer center between 2017-2019 and followed up until October 30th,2022.We analyzed demographic,medical recorded,histopathologic characteristics,imaging and endoscopic,and follow-up data.The Kaplan-Meier method and Cox proportional hazards modeling were used to analyze the difference of survival outcome by treatments.Inverse probability of treatment weighting(IPTW)was used to minimize potential confounding factors.RESULTS We retrospectively analyzed patients who underwent ESD(n=99)or surgery(n=220)or d-CRT(n=16)at the Sun Yat-sen University Cancer Center from 2017 to 2019.The median follow-up time for the ESD group,the surgery group,and the d-CRT group was 42.0 mo(95%CI:35.0-60.2),45.0 mo(95%CI:34.0-61.75)and 32.5 mo(95%CI:28.3-40.0),respectively.After adjusting for background factors using IPTW,the highest 3-year overall survival(OS)rate and 3-year recurrence-free survival(RFS)rate were observed in the ESD group(3-year OS:99.7% and 94.7% and 79.1%;and 3-year RFS:98.3%,87.4% and 79.1%,in the ESD,surgical,and d-CRT groups,respectively).There was no difference of severe complications occurring between the three groups(P≥0.05).Multivariate analysis showed that treatment method,histology and depth of infiltration were independently associated with OS and RFS.CONCLUSION For cT1N0M0 EC,ESD had better long-term survival and lower hospitalization costs than those who underwent d-CRT and surgery,with a similar rate of severe complications occurring.

Top 10 Trends Impacting the Beauty Industry in 2024

At the beginning of 2024,the cosmetic industry is bustling with prosperity and depression.On one hand,the perfume brand DOCUMENTS and the biotechnology company BIO-REGEN received financial investments.The medical company Trautec started pre-listing counseling.The first new raw material in the new year was registered.While on the other hand,the packaging material company Yiside declared bankruptcy.The beauty brand MAOGEPING failed to go public through an IPO again,after eight years’failure.Jinfa Labi,Watsons and Zhonghao Biology were all mired in recession.Hope and challenge hung over the first half month of 2024.With such a“magical”start,2024 will be definitely a year full of uncertainty.

CRITERION OF POSITIVE DEFINITENESS OF MATRICES AND SOLUTION OF INVERSE PROBLEM FOR SYSTEM OF LINEAR EQUATIONS

The class of symmetric definitely positive matrices is extremely important in the matrix theory. At present, positive definiteness of a symmetric matrix can be shown by determining the signs of its all ordered principal minors or the signs

一种基于MBD的三维尺寸完备性审查方法

为减轻人工审查MBD(model based definition)模型尺寸标注的劳动强度,对三维尺寸完备性的自动化审查进行了研究。将尺寸完备性问题归结为对相关几何要素是否定形定位的判断问题,建立了对应约束模型记录约束状态;建立了解析尺寸约束和拓扑约束的约束传播规则,并总结了几何约束的解析算法;针对尺寸缺失造成的约束不足,采用打分策略,并以指定基准或指出尺寸缺失的方式主动添加约束;提出了三维尺寸完备性检查的总体算法。通过对3DDFM原型系统的继续开发,并用三维模型实例验证了方法的有效性。

ZJ116A卷接机单支重量加工精度的优化研究

作为单支重量加工精度的重要指标,烟支的重量标准偏差反映了烟支内在品质的稳定性。前期研究找到了影响卷烟重量标准偏差的6项关键因子。该文的DOE试验选用确定性筛选设计(Definitive Screening Design,DSD)方法,通过合理安排试验的运行顺序和条件,找到了关键因子间的关系和最佳搭配。一次试验实现了筛选重要因子、描述基本特性以及找到最优方案等目标。经过ZJ116A试生产验证,重量标准偏差均值为18.86mg,重量标准偏差合格率为95%,取得了满意效果。

Siemens Definition AS128 CT维修5例

介绍了Siemens Definition AS128 CT的硬件构成,分析并总结了该设备在日常使用中出现的检查床水平移动后机架掉电、图像重建系统(image reconstruction system,IRS)计算机硬盘故障、开机时F1开关脱开、“Exam”按钮灰化等故障产生的原因及维修思路,为临床工程技术人员排除相似故障提供了参考。

Delayed versus immediate intervention of ruptured brain arteriovenous malformations:A case report

BACKGROUND Brain arteriovenous malformations(bAVMs)remains one of the most prevalent causes of intracranial hemorrhage and stroke-like syndromes in the young adult population.Although it has been agreed upon that definitive treatment using either single or multi-modal approach is warranted for successful bAVM management,much debate still revolves regarding the optimal timing of definitive treatment.CASE SUMMARY In this report,we present a case of delayed,definitive endovascular treatment for ruptured bAVM in a 21-year-old female,3 mo post-ictus.The bAVM,with a left pericallosal feeding artery and cortical draining veins,was successfully obliterated through embolization using the Onyx 18.On follow-up the patient has recommenced her daily activities and experiences only mild occasional headaches with mild motor deficits.The report leads to our review on an important issue regarding the optimal timing of ruptured bAVM definitive management and bring forward the current evidence available on delayed vs immediate definitive bAVM intervention.We also highlight current issues that need to be addressed for clearer guidelines on definitive therapy initiation.CONCLUSION Current treatment paradigms of ruptured bAVM remains elusive,with substantial heterogeneity in the current literature.A consensus on the definition of“acute”vs“delayed”,management goal,follow-up length and outcome parameters are required to support formation of a clear paradigm.

奇异鞍点问题中广义位移分裂迭代方法的半收敛性分析

Recently,some authors(Shen and Shi,2016)studied the generalized shiftsplitting(GSS)iteration method for singular saddle point problem with nonsymmetric positive definite(1,1)-block and symmetric positive semidefinite(2,2)-block.In this paper,we further apply the GSS iteration method to solve singular saddle point problem with nonsymmetric positive semidefinite(1,1)-block and symmetric positive semidefinite(2,2)-block,prove the semi-convergence of the GSS iteration method and analyze the spectral properties of the corresponding preconditioned matrix.Numerical experiment is given to indicate that the GSS iteration method with appropriate iteration parameters is effective and competitive for practical use.

Monkeypox in humans:Transmission,pathophysiology,diagnosis,treatment,prevention,and all recent updates

The Centers for Disease Control and Prevention(CDC)is monitoring an epidemic of monkeypox infection in the United States.The outbreak is now global and more than 6900 cases have already been reported.There are 83 confirmed cases among children and adolescents,as shown in the report published on November 3,2022,in the USA.However,monkeypox in pediatric patients is still infrequent(<0.3%of total cases).Among cases in the United States,16 cases were in children<5 years,12 in the age group 5-12 years,and 55 cases in adolescents 13-17 years old.In the adolescent age group,89%were male.For children<12 years of age,close physical contact with an adult household with monkeypox was the primary exposure,but for adolescents,male-to-male sexual contact was found more frequently.The CDC advised United States healthcare providers to remain vigilant for patients with a rash resembling monkeypox,even if there is no history of travel to a country with high risk.This article summarizes the history and epidemiology of monkeypox with a specific emphasis on clinical features and management in pediatric patients.

Hermite Positive Definite Solution of the Quaternion Matrix Equation Xm + B*XB = C

This paper discusses the necessary and sufficient conditions for the existence of Hermite positive definite solutions of the quaternion matrix equation Xm+ B*XB = C (m > 0) and its iterative solution method. According to the characteristics of the coefficient matrix, a corresponding algebraic equation system is ingeniously constructed, and by discussing the equation system’s solvability, the matrix equation’s existence interval is obtained. Based on the characteristics of the coefficient matrix, some necessary and sufficient conditions for the existence of Hermitian positive definite solutions of the matrix equation are derived. Then, the upper and lower bounds of the positive actual solutions are estimated by using matrix inequalities. Four iteration formats are constructed according to the given conditions and existence intervals, and their convergence is proven. The selection method for the initial matrix is also provided. Finally, using the complexification operator of quaternion matrices, an equivalent iteration on the complex field is established to solve the equation in the Matlab environment. Two numerical examples are used to test the effectiveness and feasibility of the given method. .

Towards Another Golden Decade

If one was to name the programmes that have been pushing development of the countries around the world for common prosperity in the past decade,the Belt and Road Initiative(BRI)would definitely be one of them.Also known as the Silk Road Economic Belt and the 21st Century Maritime Silk Road.

针对XML流数据的复杂Twig Pattern查询处理

XML流数据处理在研究领域引起了研究者的广泛兴趣.针对XML流数据的、具有嵌套AND/OR谓词的复杂Twig Pattern查询处理,提出一种新方法.为了提高查询处理性能,将所有Twig Pattern合并为一个共享前缀的查询树,其中,AND/OR谓词被表示为单独的抽象语法树,因而能够以文档顺序、单遍地处理复杂Twig Pattern的匹配,并避免了YFilter中对嵌套谓词进行后置处理所产生的中间结果.实验结果表明,该方法能够有效改善Twig Pattern的处理性能,尤其是在处理大文档的情况下.基于已有的研究工作,讨论如何利用DTD(document type definition)的结构和约束信息优化Twig Pattern,即这种优化是在系统运行前进行的预处理.

基于PDDL的成像卫星任务规划建模

基于对成像卫星任务规划问题的特点的深入分析,提出一种基于状态-动作模型的任务规划建模的方法:采用PDDL语言对成像卫星的领域知识进行描述,解决动作的持续时间约束、复杂的资源约束和一类特殊的外部事件约束的表达问题,最终建立成像卫星任务规划模型。通过对该建模方法的模型描述能力分析,表明该建模方法较传统规划建模方法具有较好的描述能力,能满足描述成像卫星任务规划问题的要求。

一种基于XML的Workflow过程定义语言

工作流是指一个业务操作从开始到结束的整个过程,是一系列相互衔接、自动进行的业务活动或任务,它在流程管理方面有很重要的应用。由于工作流程和业务规则的变更会经常发生,所以提供一种好的Workflow过程定义方法或语言已经成为目前工作流技术得以进一步发展和广泛应用的关键。在WPDL的基础上提出了一种基于XML的简单易用的Workflow过程定义语言。

西门子Definition双源CT罕见故障维修案例分析

简要介绍了CT稳定运行的重要性,详细分析了西门子Definition双源CT的滤过器运动电动机过流罕见故障并给出了具体的排除方法,保障了机器的正常运行,节省了维修成本,为同行维修类似故障提供了参考。

西门子系列CT典型故障维修

简要介绍了CT设备稳定运行的重要性,详细阐述了西门子Definition双源CT出现的图像无法重建故障和Emotion16排CT出现的IES(图像副台计算机)黑屏故障并给出了具体的排除方法,保障了CT设备的稳定运行,为同行维修类似故障提供了参考。

基于SPEM2XPDL模型转换的软件过程执行

SPEM(software process engineering metamodel)是国际标准化组织制定的标准元模型,正日益成为软件过程建模领域的行业标准,但在过程执行方面,SPEM还存在不足.将软件过程看作是一种特殊的工作流,提出了一种应用工作流运行机制支持软件过程执行的方法.通过将SPEM模型转换为XPDL(XML process definition language)模型,利用XPDL引擎支持SPEM模型的执行.制定了SPEM和XPDL之间的映射规则,设计了转换算法并开发了转换引擎.该方法被应用在SoftPM项目中,成功地基于XPDL引擎Shark实现了对软件过程模型的执行支持.