Log-normal censored regression model detecting prognostic factors in gastric cancer:A study of 3018 cases

AIM:To investigate the efficiency of Cox proportional hazard model in detecting prognostic factors for gastric cancer.METHODS:We used the log-normal regression model to evaluate prognostic factors in gastric cancer and compared it with the Cox model.Three thousand and eighteen gastric cancer patients who received a gastrectomy between 1980 and 2004 were retrospectively evaluated.Clinic-pathological factors were included in a log-normal model as well as Cox model.The akaike information criterion (AIC) was employed to compare the efficiency of both models.Univariate analysis indicated that age at diagnosis,past history,cancer location,distant metastasis status,surgical curative degree,combined other organ resection,Borrmann type,Lauren's classification,pT stage,total dissected nodes and pN stage were prognostic factors in both log-normal and Cox models.RESULTS:In the final multivariate model,age at diagnosis,past history,surgical curative degree,Borrmann type,Lauren's classification,pT stage,and pN stage were significant prognostic factors in both log-normal and Cox models.However,cancer location,distant metastasis status,and histology types were found to be significant prognostic factors in log-normal results alone.According to AIC,the log-normal model performed better than the Cox proportional hazard model (AIC value:2534.72 vs 1693.56).CONCLUSION:It is suggested that the log-normal regression model can be a useful statistical model to evaluate prognostic factors instead of the Cox proportional hazard model.

Automatic Sleep Spindle Detection with EEG Based on Complex Demodulation Method and Decision Tree Model

Sleep spindle is the characteristic waveform of electroencephalogram (EEG) which is important for clinical diagnosis. In this study, an automatic sleep spindle detection method was developed. The EEG signals were recorded based on the standard polysomnogram (PSG) measurement. A preprocessing procedure is introduced to exclude the unnecessary data segments and normalized the necessary data segments. Complex demodulation method is adopted to detect the candidate sleep spindle waveforms and calculate the features. The sleep spindles are recognized based on a decision tree model. Finally, the detected sleep spindles were utilized to amend the sleep stage recognition results. The sleep EEG data from 3 patients with sleep disorders were analyzed. The obtained results showed that the detected sleep spindles in EEG signal improved the accuracy of sleep stage recognition.

Analysis the Dynamics of SIHR Model: Covid-19 Case in Djibouti

The Covid-19 epidemic is an emerging infectious disease of the viral zoonosis type caused by the coronavirus strain SARS-CoV-2, it is classified as a human-to-human communicable disease and is currently a pandemic worldwide. In this paper, we propose conceptual mathematical models of the epidemic dynamics of four compartments. We have collected data from the Djibouti health ministry. We study the positivity, boundedness, existence and uniqueness of the weak solution. Next, we define the Basic reproduction number by the method of the DFE and EEP. Then, we study the local and global stability and the bifurcation analysis of equilibrium to examine its epidemiological relevance. Finally, we analyze the fit of the data in comparison with the result of our mathematical results, to validate the model and estimate the important model parameters and prediction about the disease. We consider the real cases of Djibouti from 15th March to 15th May 2021.

Is Chemokine Receptor CCR9 Required for Synovitis in Rheumatoid Arthritis? Deficiency of CCR9 in a Murine Model of Antigen-Induced Arthritis

Objectives: Monocytes/macrophages accumulate in the synovial membrane in rheumatoid arthritis and play a key role in disease pathogenesis, contributing to inflammation, cartilage destruction and bone erosion. Identification of molecules involved in monocyte/macrophage recruitment in inflammation is crucial for development of therapeutic interventions. Chemokine receptor CCR9 is up-regulated on these cells in peripheral blood and synovium of rheumatoid patients. This study investigated the course of antigen-induced arthritis in CCR9 deficient C57BL/6 mice in comparison to wild type animals to determine whether CCR9 is critical for disease severity and progression. Methods: Methylated bovine serum albumin was used for induction of uni-lateral arthritis by direct injection into the knee joints of preimmunized animals. Arthritis is confined to the injected joint allowing comparison with the normal opposing joint. Clinical severity of arthritis was assessed by measuring swelling in the arthritic joint in comparison to the normal joint. Histological analysis was performed to assess the extent of leukocyte infiltration and cartilage depletion. Results: Levels of swelling were not significantly different between wild type and CCR9 deficient mice. Similarly there was no significant difference in histological severity of arthritis when comparing CCR9-deficient mice to wild type mice. Conclusions: CCR9 was not required for development of synovial inflammation and cartilage destruction in the anti-gen-induced model of arthritis in C57BL/6 mice in this study. This may reflect a true lack of a pathogenic role of CCR9 on monocyte/macrophage function in vivo or it may reflect differences in the current antigen-induced arthritis model when compared to human RA.

Mathematical Modeling of the Influence of the Wind Field Structure in the Atmosphere on the Cloud Formation Processes

The state of the physics of convective clouds and cloud seeding is discussed briefly. It is noted that at the present time there is a transition from the stage of investigation of “elementary” processes in the clouds to the stage of studying the formation of macro- and microstructural characteristics of clouds as a whole, taking into account their system properties. The main directions of the development of cloud physics at the upcoming stage of its development are discussed. The paper points out that one of these areas is the determination of the structure-forming factors for the clouds and the study of their influence on their formation and evolution. It is noted that one of such factors is the interaction of clouds with their surrounding atmosphere, and the main method of studying its role in the processes of cloud formation is mathematical modeling. A three-dimensional nonstationary model of convective clouds is presented with a detailed account of the processes of thermohydrodynamics and microphysics, which is used for research. The results of modeling the influence of the wind field structure in the atmosphere on the formation and evolution of clouds are presented. It is shown that the dynamic characteristics of the atmosphere have a significant effect on the formation of macro- and microstructural characteristics of convective clouds: the more complex the structure of the wind field in the atmosphere (i.e., the more intense the interaction of the atmosphere and the cloud), the less powerful the clouds are formed.

地球与行星内源磁场建模研究进展

太阳系绝大多数行星都拥有随星体自转而共转的内源磁场.随着人类不断地进行深空探测,人们已经对所有已知具有内源磁场的太阳系星体建立起了其对应的行星磁场模型.行星磁场建模是深入研究行星内部动力学过程、探究行星演化历史、理解行星磁场与太阳风相互作用、认识行星磁场对高能带电粒子的屏蔽效应等多种研究方向的重要基础.同时,行星磁场建模也是一项多学科交叉的研究工作,其涉及到行星磁场建模理论、内外源磁场场源分离、参数反演方法与方程优化等多方面的研究.本文综述了地球与太阳系其他行星,包括月球以及木卫三两颗卫星在磁场建模方向的研究进展,描述了行星内源磁场的特征,整理了太阳系行星最准确的全球磁场模型.本文首先从行星磁场的数学建模方法开始,梳理了自高斯时代以来磁场建模技术的发展历史,介绍了行星磁场建模研究的热点方法.文章最后展望了未来行星磁场建模研究的发展趋势,以及我国未来的深空探测计划对行星磁场建模研究的可能贡献.

城市发展对临空经济区空间异质性影响研究

临空经济区建设对推动产业结构升级、促进经济高质量增长至关重要。为探究城市发展对临空经济区的空间异质性影响,以全国51个国家级及地方临空经济区为研究对象,采用核密度分析法可视化并充分讨论了临空经济区发展的演化过程,同时构建了融合综合交通时间、航空运输业务水平等属性的复合邻近关系,在此基础上提出了基于多维距离的地理加权回归模型(MD-GWR),并以此对临空经济区发展的驱动因素进行建模,从而提出了促进各地区临空经济增长的差异化政策。研究表明:MD-GWR模型相比经典GWR模型拥有更优异的拟合精度,较经典GWR模型与OLS模型分别提升了12.52%与40.17%;城市经济体量、商业贸易、招商引资、企业规模、科技实力、产业结构对临空经济增长影响均存在显著的空间异质性,对不同地区的影响程度与方向具有较大差异;为推动临空经济区高质量发展,应进一步提升东北及西北地区城市的对外开放水平,提高东部地区城市的外商投资质量,完善东北及中西部地区城市的产业结构调整政策,加大乌鲁木齐、长春等城市的科技研发资金投入。研究结果有助于明确我国各城市临空经济区的发展规律与驱动机理,为制定具有针对性且差异化的临空经济区发展政策提供理论依据,对促进临空经济高质量增长具有重要意义。

海洋采油平台天然气泄漏扩散实验与数值模拟分析

基于中国石化胜利油田典型海洋平台,搭建缩比为1∶22的实验平台,选取储罐、天然气处理系统及三相分离器等设备作为气体泄漏源,开展基于Froude数相似理论的甲烷泄漏扩散规律测试实验,同时,采用泄漏及爆炸分析软件FLACS建模,进行典型泄漏工况的数值模拟。通过气体泄漏实验和数值模拟结果对比,两组数据的总平均误差为8.70%,验证数值模型具有较好的预测精度;结合数值模型和实验数据,进一步分析了海洋平台甲烷泄漏的扩散规律,为海洋平台油气泄漏安全风险防控提供了理论和数据支撑。

城市交通新基建网络建设展望——目标、内涵与路径

建设世界一流的交通基础设施体系已上升成为国家战略,对城市交通而言,从传统基础设施迈向新型基础设施(以下简称“新基建”)是高质量发展的必然选择。探讨了城市交通新基建网络建设的目标、内涵与路径,强调新基建不等同于抛弃传统价值,仍需紧密围绕服务于人的需求、组织城市高效运行、引领生态战略落地、筑牢网络韧性防线、与新业态同频共振、提升行业管理效能等目标推动建设。从设施-运输-信息-能源四网融合、物理-数字-社会三元空间融合、为设施“规-建-养-运”全面赋能、建立全息认知-全视角评估-全场景推演-全要素调控闭环4个维度出发,解析城市交通新基建网络的构建与运行内涵并展望其发展的未来形态。最后,从规划编制方法与技术创新、新基建网络智能体构建、城市交通基础设施与能源跨网融合角度探讨新时期城市交通的发展路径。

Intelligent Control Mechanism of Part Picking Operations of Automated Warehouse

This paper studies the part picking operations of a ut omated warehouse. It assumed the demand of picking orders of automated warehouse are dynamic generated. Once the picking orders of certain period of time are kn own, it is necessary to decide an efficient order picking sequence and routing t o minimize the total travel distance to complete those orders. Assumed there are n i items to be picked in order O i. Each item in the picking ord er is located in different locations in the warehouse. Since it is possible the same items appear in the different picking orders, it will reduce the picking di stance if these orders can be batched and picked in one path. However, there are several constraints for the order batching and order picking operations. These constraint are (1) the crane of the automated warehouse has the carrying capacit y of C, and (2) for the management convenience, it is assumed that one picki ng order must be completed in one path. Because of the complexity of problem, it is inefficient to solve the problem by analytical approach. Although the heuristic method can significantly reduce of the computation time, the quality of the solution is always unacceptable. It is the intention of this paper to integrate the advantages of neural network and simulated annealing technique to develop the control mechanism for the planning of order picking operations of automated warehouse. A systematic computational simulation is conducted to evaluate the proposed method. The results show the pr oposed method can generate superior solution in most cased.

Zavkhan River and Its Catchment Area Delineation Using Satellite Image

The purpose of this research is to define initial parameters of Khyargas Lake-Zavkhan River and its catchment area using satellite images. The study has been done by two datasets: 1) Shuttle Radar Topography Mission (SRTM) at a horizontal spatial resolution of 90 meters, 2) The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) at a horizontal spatial resolution of 30 meters, using two different models of ArcHydro and Integrated Land and Water Information System (ILWIS) softwares. Main methods of models, that were used in this research are the Deterministic-8, the steepest slope, the spread, the seek computations and the trace analysis. Moreover, input data of the modeling are digital elevation model (DEM) and lake position, outlet location of the river. DEM based ArcHydro model was run on the both datasets, and ILWIS model was run on SRTM data. Several intermediate results were produced while the models run, and initial parameters of the Zavkhan River, its catchment area have been defined at the end of the model. Moreover, final results of the models were compared with each other and with the result of previous research, and with the reality. The result of this study can be used in baseline and advanced research on the catchment area. Besides of that, the result can define a spatial boundary of study on Zavkhan River and its catchment area. Moreover, it would have support for decision-making on ground and surface water resource, distribution and management. Further research, which will cover the entire territory of Mongolia, has to be done using same methodology. The 332nd decision on “River catchment areas of Mongolia” of the Minister of Nature, Environment and Tourism in 2009 has to renew, if a result of that study would be accepted from vocational organization and experts.

精细化涡扇发动机过渡态建模与验证

为了提高涡扇发动机过渡态性能仿真的精度并实现过渡态性能计算模型的工程应用,梳理了不同因素对涡轮发动机过渡态性能的影响机理,介绍了各影响因素的建模方法,在此基础上建立了精细化涡扇发动机整机过渡态性能仿真模型。研究分析了总温、总压和燃油流量传感器的过渡态效应及其建模方法。最终利用涡扇发动机整机地面台架加减速性能试验数据对精细化过渡态模型进行了验证,结果表明:高低压物理转速、推力、压气机出口总压和内涵排气温度的平均误差分别为0.45%,0.77%,0.61%,0.44%和1.77%,最大误差分别为2.82%,1.92%,7.45%,5.67%,5.28%,加速时间的误差小于0.26s。本文揭示了过渡态性能仿真模型误差的机理。

矿产资源开发视角下基于SRP模型的秦岭“生命共同体”生态脆弱性评价

生态脆弱性评价作为开展生态保护的依据之一,对于区域生态建设具有重要作用。为系统分析秦岭“生命共同体”生态脆弱性的时空分布特征和主要驱动因子,从山水林田湖出发,根据山水林田湖系统在秦岭地区的典型性,构建矿产资源开发视角下秦岭“生命共同体”概念模型,并利用生态敏感性-生态恢复力-生态压力度(SRP)模型选取32个评价指标构建秦岭“生命共同体”评价指标体系,结合主成分分析(PCA)法对秦岭“生命共同体”2013年、2017年、2020年3期生态脆弱性进行定量评价。结果表明:(1)矿产资源开发视角下秦岭“生命共同体”的生态脆弱性空间分布呈东北高、西南低的特征,在3期内经历了从以极度脆弱为主到以微度脆弱为主,整体上生态脆弱性呈好转趋势,但渭南市生态脆弱性程度趋向严重;(2)工业废弃物排放量、采矿业能源消耗量、耕地面积、地区生产总值、人口密度、环保投资、水库库容是影响秦岭“生命共同体”生态脆弱性的主要因素。该研究结果可为秦岭“生命共同体”建设和生态修复与保护提供理论依据。

贸易效率视角下中国自新兴市场国家进口潜力研究——基于时变SFA模型的测度

文章选取了2006—2021年间代表性较强的18个新兴市场国家进口贸易相关数据,通过构建时变随机前沿引力(SFA)模型和进口贸易非效率模型,实证分析了中国从新兴市场国家的进口贸易效率、潜力及影响因素。同时,考虑到进口贸易效率自身在不同国家之间存在着较大的异质性,故而在控制个体与时间固定效应基础上对时变SFA模型进行了进一步的估计,其结果保持一致。结果显示,双方经济规模、本国人口数量、地理距离和共同语言对中国自新兴市场国家的进口贸易都有着显著影响,贸易非效率项仍是制约中国自其进口贸易的关键因素,而进口贸易效率主要由关税水平、班轮运输指数、经济自由度所决定。未来,中国需要进一步加强与新兴市场国家的贸易运输基础设施建设,优化进口商品结构,降低关税与非关税壁垒,以提高从新兴市场国家的进口贸易效率。

塔里木盆地沙井子断裂带油气地质条件及勘探潜力

通过钻井、地震和野外露头等资料的综合分析,根据构造特征及派生断层的差异性,将塔里木盆地沙井子断裂带划分为东段、西段、中段及阿恰段等4段。沙井子断裂带具有加里东晚期开始发育、海西期—印支期—燕山期多期活动、喜马拉雅期定型的演化特征,发育构造、地层、潜山等多种类型的圈闭,是油气运聚的有利区。研究表明:①下寒武统玉尔吐斯组和中奥陶统萨尔干组2套优质烃源岩为研究区油气的主要来源;②寒武系盐下丘滩相白云岩、志留系柯坪塔格组潮坪-滨岸复合沉积相的潮汐水道砂岩及滨岸砂坝、三叠系俄霍布拉克组扇三角洲及克拉玛依组辫状河三角洲砂岩为研究区的3套主要储层;③中寒武统厚层膏盐岩、志留系塔塔埃尔塔组泥岩夹层及依木干他乌组厚层泥岩、三叠系俄霍布拉克组及克拉玛依组泥岩夹层为研究区的3套主要盖层;④油气充注呈现多期性、以晚期为主的特点。建立了志留系、三叠系“构造主控、多期充注、晚期成藏”和寒武系盐下“构造主控、连续充注”2种油气成藏模式,指出沙井子断裂带下盘的志留系和三叠系、上盘阿恰段的寒武系盐下为有利勘探区。

不同坡向雪岭云杉天然更新影响因素分析

为了解不同坡向环境因子对雪岭云杉林天然更新的影响,在天山北坡中段同一海拔雪岭云杉林的阴坡、半阴坡、半阳坡、阳坡设置系列样方开展调查,构建不同坡向环境因子-更新指数结构方程模型,根据各坡向环境特征分析云杉幼苗存活现状与环境因素间的关系。结果表明:(1)半阴坡和半阳坡更适宜幼苗的存活和生长,二者更新指数(0.065、0.057)显著高于阴坡和阳坡;(2)凋落物对雪岭云杉更新有双重作用,凋落物未分解层过厚不利于更新,丰富的有机质可促进土壤形成高氮环境,有利于林下幼苗更新;(3)不同坡向环境因子对更新指数的作用强度依次为:全氮含量(0.60)>成年树密度(0.46)>凋落物半分解层(0.37)>全钾含量(0.24)>有机质含量(0.23)>全磷含量(-0.16)>速效磷含量(-0.32)>凋落物未分解层厚度(-0.34)。综合来看,该区域的雪岭云杉幼苗在郁闭度大小为0.6左右,凋落物厚度为2.5 cm左右,土壤全氮、全钾含量较高的半阴坡、半阳坡更新较好。

基于UTAUT模型的在线心理咨询平台用户使用行为研究

目的:基于整合技术接受模型(UTAUT)和信息系统成功模型D&M,探究在线心理咨询平台用户使用行为的影响因素。方法:随机抽取温州市鹿城区、瓯海区、龙湾区、洞头区465名调查对象进行问卷调查,构建结构方程并运用Smart PLS 2.0进行假设检验。结果:信息质量、努力期望、感知信任和感知愉悦性对在线心理咨询平台用户的使用意愿均有正向影响作用(P<0.05),其影响程度按照路径系数从大到小依次为感知信任(0.199)、感知愉悦性(0.139)、信息质量(0.135)、努力期望(0.095)。同时,便利条件(0.134)和使用意愿(0.531)均对用户的使用行为有显著的正向影响作用(P<0.01)。结论:建议该类平台一方面应重视用户隐私信息保护,提高个体信任度;另一方面应充实交互性功能,增强用户参与度和愉悦性,精准定位用户个性化需求。同时政府应加强对在线心理咨询平台有效监管,共同促进平台网络生态有效构建。

运城盆地鸣条岗地裂缝展布特征与成因分析

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