复杂地铁车站多工况洪水入侵规律与人员疏散路径分析

【目的】在城市地下空间综合化高速开发的同时,极端降雨所引发的城市内涝灾害频繁发生,洪水倒灌入侵地铁车站事故导致了严重的人员伤亡和财产损失。洪水经由车站流入隧道对运营中的车辆设备及乘客人员造成重大威胁,为预防和应对多种工况下洪水侵入地铁系统灾害,通过数值分析方法,模拟不同工况洪水入侵和淹没复杂地铁车站的全过程,并预测计算流入隧道的洪水量。【方法】以南宁市地铁换乘车站明秀路站为原型,构建三维数值仿真模型。研究防淹门不同启闭条件下,百年一遇入侵洪水高度、50 cm和30 cm入侵洪水高度水位洪水入侵复杂地铁车站的全过程。基于Volume of Fluid(VOF)模型方法,模拟分析了不同工况下洪水在地铁车站内的淹没区域范围与积聚深度,探讨洪水激增规律以及危险区域分布情况。针对百年一遇洪水入侵工况,分析了物业开发层的水深分布规律,并通过计算得到该区域的人员疏散路径。【结果】结果显示:在洪水入侵灾害中,明秀路站被淹没速度和淹没高度随入侵洪水高度的提升而加快和增加;关闭防淹门可以防止大量洪水流入隧道,但是将会严重加剧站内积水;与地铁车站相连的物业开发层可能导致洪水更快更多地入侵淹没明秀路站,分布密集且狭小的通道口处积水较深。【结论】结果表明:数值模拟的方法可以较为容易地计算得到洪水入侵灾害中地铁车站的淹没过程和范围,通过改变出入口条件可以得到例如防淹门启闭措施对不同入侵洪水高度洪水入侵的影响,可为灾前预防隐患和灾时应急措施提供参考。

COPD病人肺康复运动训练的质性研究

目的:探讨慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)病人肺康复运动训练的影响因素,为更好地开展肺康复运动提供指导,从而进一步提高慢性阻塞性肺疾病病人的运动耐量和生活质量。方法:采用质性研究中现象学方法,以半结构式深入访谈了12例慢性阻塞性肺疾病病人,包括有意愿、已参与和拒绝或中途退出肺康复运动项目的病人。结果:运用Colaizzi分析程序进行分析,得到影响病人肺康复运动训练的因素,并归纳为4个主题:慢性阻塞性肺疾病病人的个人因素;客观因素;家庭成员的态度及锻炼环境因素;住院期间医护人员因素。结论:加强对慢性阻塞性肺疾病病人肺康复运动的宣教,提高病人的依从性和积极性,在临床护理中,发挥医务人员的主导作用,鼓励病人家属的支持并合理的利用社区资源,促使病人形成健康的行为习惯,以促进康复、提高生活质量。

重组人促红细胞生成素对新生鼠脑室周围白质软化的影响及其机制

目的观察重组人促红细胞生成素(rEPO)对新生鼠脑室周围白质软化(PVL)的影响,并探讨其机制。方法选取3日龄新生鼠,随机分为PVL模型组、rEPO干预组及假手术组各24只。PVL模型组、rEPO干预组通过分离并结扎新生鼠左颈总动脉,随后给予低氧混合气体缺氧70 min进行PVL建模;假手术组只分离左颈总动脉,但不行结扎和缺氧处理。rEPO干预组在术后1 d开始连续腹腔注射rEPO 7 d,PVL组及假手术组腹腔注射相同容积生理盐水;三组分别于术后3、7、14 d随机选取8只处死并取脑组织,采用HE染色观察侧脑室及脑室周围白质组织形态、卢卡斯固蓝染色观察髓鞘组织形态,采用免疫组织化学法检测脑室周围白质区少突胶质细胞和髓鞘标志物2',3'-环核苷酸3'-磷酸二酯酶(CNPase)、少突胶质细胞前体标志物神经胶质抗原2(NG2)。结果PVL模型组及rEPO干预组可见左侧侧脑室较对侧扩大,脑室周围白质组织细胞水肿并伴囊腔、胶质瘢痕形成,髓鞘水肿、断裂,神经纤维走行紊乱等;术后同时点rEPO干预组病理改变均较模型组减轻,假手术组各时点无明显病理改变。术后同时点比较,三组新生鼠脑室周围白质组织CNPase表达假手术组>rEPO干预组>PVL模型组;NG2表达rEPO干预组>PVL模型组>假手术组(P均<0.05)。结论rEPO可通过增加少突胶质细胞及少突胶质细胞前体促进少突胶质细胞成熟及髓鞘形成,从而减轻脑缺氧、缺血引发的新生鼠PVL。

城市轨道交通保护区市政施工安全影响评估及安全保护

近年来随着城市轨道交通建设规模不断扩大,城市轨道交通保护区内建设项目管理日益重要。文章以南宁市轨道交通2号线东延线配套道路工程及南宁市良玉大道(平乐大道—东风路)缆线管廊工程施工对既有城市轨道交通结构安全产生影响为例,采用有限元软件,模拟该市政工程在不同施工阶段引起南宁市轨道交通2号、3号线平良立交站部分附属结构变形以及产生的内力影响并进行分析,提出在轨道交通保护区内市政施工的安全保护措施。

Effects of Mg2+ on the binding of the CREB/CRE complex:Full-atom molecular dynamics simulations

Metal ions play critical roles in the interaction between deoxyribonucleic acid(DNA) and protein.The experimental research has demonstrated that the Mg^2+ ion can affect the binding between transcription factor and DNA.In our work,by full-atom molecular dynamic simulation, the effects of the Mg^2+ ion on the cyclic adenosine monophosphate(cAMP)response element binding protein(CREB)/cAMP response elements(CRE) complex are investigated.It is illustrated that the number of hydrogen bonds formed at the interface between protein and DNA is significantly increased when the Mg^2+ ion is added.Hence, an obvious change in the structure of the DNA is observed.Then the DNA base groove and base pair parameters are analyzed.We find that, due to the introduction of the Mg2+ ion, the DNA base major groove becomes narrower.A potential mechanism for this observation is proposed.It is confirmed that the Mg^2+ ion can enhance the stability of the DNA–protein complex.

Exact inference for two exponential populations with competing risks data

In a reliability comparative test, the joint censoring model is usually adopted to evaluate the performances of units with the same facility. However, most researchers ignore the possibility that there is more than one factor for the failure when a test unit fails. To solve this problem, we consider a joint Type-II hybrid censoring model for the analysis of exponential competing failure data. Based on the maximum likelihood theory, we compute the maximum likelihood estimators(MLEs) of parameters and then obtain the condition ensuring MLEs existence for every unknown parameter. Then we derive the conditional exact distributions and corresponding moment properties for parameters by the moment generating function(MGF). A Monte-Carlo simulation is conducted to compare the performances of different ways. And finally, we conduct a numerical example to illustrate the proposed method.

J/ψProduction Associated with the W-Boson at the 7 TeV Large Hadron Collider

We calculate the complete next-to-leading order(NLO)QCD corrections to J/ψ+W associated production within the factorization formalism of nonrelativistic QCD at the 7 TeV Large Hadron Collider.We provide the numerical results for the leading-order(LO),NLO QCD corrected differential cross sections of the J/ψtransverse momentum by adopting the event selection criteria requested by the ATLAS experiment.It is found that the differential cross section at the LO is significantly enhanced by the NLO QCD corrections.

重复脉冲试验法在凸极式转子匝间短路测试中的应用

基于行波理论的重复脉冲试验法(以下简称:RSO法)在隐极式发电机转子匝间短路实际应用测试中得到了大量的验证,使用效果良好,并结合工作实际进行了试验验证,最终证明了RSO法在凸极式同步电动机转子匝间短路测试方面具有一定的适用性。

Rif1 interacts with non-canonical polycomb repressive complex PRC1.6 to regulate mouse embryonic stem cells fate potential

Mouse embryonic stem cells(mESCs)cycle in and out of a transient 2-cell(2C)-like totipotent state,driven by a com-plex genetic circuit involves both the coding and repetitive sections of the genome.While a vast array of regulators,including the multi-functional protein Rif1,has been reported to influence the switch of fate potential,how they act in concert to achieve this cellular plasticity remains elusive.Here,by modularizing the known totipotency regulatory factors,we identify an unprecedented functional connection between Rif1 and the non-canonical polycomb repres-sive complex PRC1.6.Downregulation of the expression of either Rif1 or PRC1.6 subunits imposes similar impacts on the transcriptome of mESCs.The LacO-LacI induced ectopic colocalization assay detects a specific interaction between Rif1 and Pcgf6,bolstering the intactness of the PRC1.6 complex.Chromatin immunoprecipitation followed by sequencing(ChIP-seq)analysis further reveals that Rif1 is required for the accurate targeting of Pcgf6 to a group of genomic loci encompassing many genes involved in the regulation of the 2C-like state.Depletion of Rif1 or Pcgf6 not only activates 2C genes such as Zscan4 and Zfp352,but also derepresses a group of the endogenous retroviral element MERVL,a key marker for totipotency.Collectively,our findings discover that Rif1 can serve as a novel auxiliary component in the PRC1.6 complex to restrain the genetic circuit underlying totipotent fate potential,shedding new mechanistic insights into its function in regulating the cellular plasticity of embryonic stem cells.

Exact Inference for Joint Type-I Hybrid Censoring Model with Exponential Competing Risks Data

Assuming that the failure time under different risk factors follows the independent exponential distribution, a joint model under Type-I hybrid censoring is addressed in detail. Based on the Maximum likelihood estimates(MLEs) of unknown parameters, we obtain exact distributions of MLEs by using the moment generating function(MGF). Confidence intervals(CIs) of parameters are constructed through both the exact method and the parametric bootstrap method. Then we compare the performances of different methods by Monte Carlo simulations. Finally, the validity of the proposed models and methods are demonstrated by a numerical example.

Statistical Inference for a Simple Step Stress Model with Competing Risks Based on Generalized Type-ⅠHybrid Censoring

This paper investigates a simple step-stress accelerated lifetime test(SSALT)model for the inferential analysis of exponential competing risks data.A generalized type-I hybrid censoring scheme is employed to improve the efficiency and controllability of the test.Firstly,the MLEs for parameters are established based on the cumulative exposure model(CEM).Then the conditional moment generating function(MGF)for unknown parameters is set up using conditional expectation and multiple integral techniques.Thirdly,confidence intervals(CIs)are constructed by the exact MGF-based method,the approximate normality-based method,and the bias-corrected and accelerated(BCa)percentile bootstrap method.Finally,we present simulation studies and an illustrative example to compare the performances of different methods.