血低密度脂蛋白胆固醇存在下限阈值吗? ODYSSEY OUTCOMES研究结果带来的新思考

百年胆固醇学说已深入人心,其在动脉粥样硬化（AS）的预防、治疗及机制研究中发挥着极为重要的作用（[1]）。胆固醇学说的核心是没有胆固醇就没有AS,更无从谈论动脉粥样硬化性心血管疾病（ASCVD）。事实上,大量基础与临床研究证据提示,低密度脂蛋白胆固醇（low-density lipoprotein cholesterol,LDL-C）与ASCVD的发生与发展存在一定程度的因果关系，被称之为ASCVD的“致病陛”危险因素。以此理论为基础的各种血脂异常管理指南毫无例外地将LDL-C视为ASCVD防治的首要干预目标。

基于短信的煤矿瓦斯分级超限报警系统

本文根据煤矿瓦斯监控的实际需求,设计并实现了一个煤矿瓦斯短信报警系统。该系统从"KJ90瓦斯监控联网系统"(用于瓦斯浓度等监测)获取监控数据,对这些数据进行报警阈值超限分析,通过短消息以分级报警方式将煤矿安全报警信息发送给煤矿生产人员及管理人员实现分级超限报警的煤矿安全生产远程自动化管理。此系统目前已在煤矿大力实施应用,实践证明具有良好的应用价值。

农业产品的风险评估及其应用

如何评估农产品的安全和控制其风险已成为现代社会共同关注的焦点.笔者在鞅论的理论基础上,借助随机模型对农产品风险进行了刻画和评估,并给出了相关的概率指标.

高速铁路CPII控制网复测稳定性分析指标合理性深入研究

根据现行高速铁路工程测量规范要求,CPII控制点的稳定性主要是从原测与复测坐标分量较差和相邻点间坐标差之差的相对精度两项指标判断。在实际应用过程中发现,现行规范中CPII控制点原测与复测坐标分量较差的限差阈值15mm和相邻CPII点间坐标差之差相对精度的限差阈值1/80000对小于600m的短边而言均存在缺陷,这会影响评价CPII控制点复测稳定性的准确度。因此,本文分别推导了基于GNSS测量CPII点的两项稳定性分析指标的合理限差,研究结果对指导实际工作和完善高速铁路工程测量规范有一定参考价值。

汕头至汕尾铁路汕头湾海底隧道设计综述

汕头湾海底隧道为设计时速350 km的单洞双线高铁海底隧道,具有高水压(隧底最大水压力达0.97 MPa)、高侵蚀性(海域段落氯盐侵蚀环境等级L3)和高烈度地震区(8度地震区)的特点。隧道施工工法复杂,涉及矿山法(海域矿山法、陆域矿山法)、盾构法、明挖法、矿山法+盾构空推法。为进一步探究海底隧道的设计施工关键技术,对汕头至汕尾铁路汕头湾海底隧道设计及关键技术进行阐述,有效解决了盾构机整体无损拆解、穿活动断层带抗震抗断、阈值泄压限排、盾构接缝防水、穿越复合地层适应性、防灾疏散救援、隧道全生命周期健康监测等关键技术问题。

PCA weight and Johnson transformation based alarm threshold optimization in chemical processes

To alleviate the heavy load of massive alarm on operators, alarm threshold in chemical processes was optimized with principal component analysis(PCA) weight and Johnson transformation in this paper. First, few variables that have high PCA weight factors are chosen as key variables. Given a total alarm frequency to these variables initially, the allowed alarm number for each variable is determined according to their sampling time and weight factors. Their alarm threshold and then control limit percentage are determined successively. The control limit percentage of non-key variables is determined with 3σ method alternatively. Second, raw data are transformed into normal distribution data with Johnson function for all variables before updating their alarm thresholds via inverse transformation of obtained control limit percentage. Alarm thresholds are optimized by iterating this process until the calculated alarm frequency reaches standard level(normally one alarm per minute). Finally,variables and their alarm thresholds are visualized in parallel coordinate to depict their variation trends concisely and clearly. Case studies on a simulated industrial atmospheric-vacuum crude distillation demonstrate that the proposed alarm threshold optimization strategy can effectively reduce false alarm rate in chemical processes.

One-dimensional consolidation of double-layered soil with non-Darcian flow described by exponent and threshold gradient

Based on non-Darcian flow law described by exponent and threshold gradient within a double-layered soil, the classic theory of one-dimensional consolidation of double-layered soil was modified to consider the change of vertical total stress with depth and time together. Because of the complexity of governing equations, the numerical solutions were obtained in detail by finite difference method. Then, the numerical solutions were compared with the analytical solutions in condition that non-Darcian flow law was degenerated to Dary's law, and the comparison results show that numerical solutions are reliable. Finally, consolidation behavior of double-layered soil with different parameters was analyzed, and the results show that the consolidation rate of double-layered soil decreases with increasing the value of exponent and threshold of non-Darcian flow, and the exponent and threshold gradient of the first soil layer greatly influence the consolidation rate of double-layered soil. The larger the ratio of the equivalent water head of external load to the total thickness of double-layered soil, the larger the rate of the consolidation, and the similitude relationship in classical consolidation theory of double-layered soil is not satisfied. The other consolidation behavior of double-layered soil with non-Darcian flow is the same as that with Darcy's law.

家族性Ⅱ型糖尿病核心家系的遗传方式分析

目的 对 1992～ 1998年门诊及住院的家族性Ⅱ型糖尿病 (DM)患者 177个大家系及其中 2 14个核心家系的遗传方式进行研究 ,以探讨该病的遗传学特点。方法 采用家系分析、分离分析、多基因分析和阈值模式分析的方法 ,对家族性Ⅱ型DM大家系及核心家系进行研究。结果 177个大家系的Ⅱ型DM的遗传度为 143.0 6 %± 3 .3% ,提示在这些家系中有一个显性主基因存在。 2 14个核心家系中 ,U×U婚配型的子代分离比为 0 .470 3,U×A婚配型的分离比为 0 .483 8,A×A婚配型的分离比为 0 .6 712。多基因分析和分离分析显示 ,U×A家系不符合多基因遗传和常染色体隐性(AR)遗传 ,符合常染色体显性 (AD)遗传 ,U×U家系既不符合AD遗传 ,又不符合AR遗传。结论 家族性Ⅱ型DM的遗传方式表现遗传异质性 。