An empirical study on operational diversification and performance of China′s property insurance companies

本文对我国财产保险公司1999年~2005年多元化经营与绩效之间的关系进行实证研究。通过多元回归模型分析,我们发现,财险公司产品多元化与公司绩效有着非线性关系,经营区域多元化对公司绩效有显著正向影响。同时,财险公司产品多元化与经营区域多元化之间存在交互关系,并对公司绩效有负向影响,产品多元化经营是否能提高公司绩效因其经营区域多元化程度的不同而不同。实证结果还显示,公司规模和集团化对财险公司绩效有显著的正向影响,而投资资产比例与财险公司绩效没有显著的影响关系。This paper investigated the relationship between operational diversification and performance of property insurance companies in China during the period of 1999-2005.Our empirical analyses showed that there was a nonlinear relationship between product diversification and insurer′s performance;and geographic diversification had a positive effect on overall performance.Moreover,there was an interactive relationship between product diversification and geographic diversification and had a negative effect on insurer′s performance.Whether product diversification could enhance performance varied with the degree of geographic diversification.The empirical results also indicated that the firm size and group status were positively related to insurer′s financial performance,while the ratio of investment assets had no visible impact on the performance of property insurance companies.国家社会科学基金项目(06BJY005);福建省社会科学规划项目(2006B2135

小麦株高遗传解析

株高作为小麦的重要农艺性状,与其抗倒伏性、籽粒产量和收获指数密切相关。本研究利用科农9204×京411重组近交系群体,构建了一个包括119,566个标记的高密度遗传连锁图谱,在12个环境下共检测到8个株高QTL。其中,qPh-2B、qPh-3A、qPh-3D、qPh-4B、qPh-5A.1和qPh-6B等可在多个环境下检测到。qPh-6B可解释9.39-20.99%的株高表型变异,缩短穗颈长和穗下节间长;来自科农9204的等位基因降低株高2.32-4.06 cm。构建了含有1,289个标记的qPh-6B靶区段的高密度图谱,结合QTL定位和比较基因组方法,将其定位于中国春6B染色体组装序列623.382 Mb-652.882 Mb区段。利用Wheat 660K和BSA分析,将qPh-2B定位于中国春587 Mb-785 Mb区段。qPh-2B为显性半矮杆基因,通过影响细胞伸长来调节株高,降秆效应为15-20 cm。该基因纯合状态下胚胎发育受阻,不能结实。矮秆杂合体植株较高秆隐性纯合体的茎秆更粗壮,籽粒较宽,千粒重较高。该研究为矮杆基因的深入挖掘奠定了基础

基于660K芯片小麦高密度遗传连锁图谱及其应用

高密度遗传连锁图谱对小麦基因定位克隆、分子育种及基因组学研究至关重要。多种分子标记被成功应用于小麦遗传图谱的构建,基于不同作图群体已释放40余个版本小麦遗传图谱,以高密度遗传图谱为桥梁,实现上述遗传图谱的整合将为分子育种奠定重要的遗传资源。本研究利用小麦科农9204×京411构建的重组自交系KJ-RIL群体及660K小麦基因组芯片(Affymetrix Wheat660 chip),绘制了包含119566个位点的小麦高密度遗传连锁图谱,图谱总长度4424.4cM,标记间平均距离为0.04cM/位点。经比较分析,该高密度遗传图谱与90K、820K高密度整合图谱及小麦基因组物理图谱均具有较好的共线性对应关系。结合前人已报道遗传图谱及其标记序列信息,以660K芯片高密度遗传连锁图谱为骨架,梳理AFLP、RFLP、RAPD、SSR、EST-SSR、STS、SRAP、DarT、SNP等标记遗传位置及基因组序列信息,构建了小麦高密度一致性整合图谱。结合表型数据、高密度遗传图谱极其基因型值,对控制穗粒数主效QTL-qKnps-4A、株高主效QTL-qPh-6B等多个QTL进行了精准定位,绘制了靶区段高密度遗传连锁图谱,该结果为靶基因的精细定位及图位克隆奠定基础

新疆塔里木盆地北部碳酸盐岩储层测井技术应用研究

该项目对新增的声波成向测井和长源距声波测井两种方法，在碳酸盐岩裂缝储层研究中的应用进行了研究。其开发了一套多功能全波数据格式转换和波形显示程序，能够实现阿特拉斯公司和哈里伯顿公司数据的读取，及哈里伯顿格式到阿特拉斯公司的转换；根据纵波和横波时差可计算一个新的裂缝指标FI，同时根据纵波时差变化率提供了另一个裂缝指标，进一步改进了综合概率模型；根据23口井的声波成象测井处理结果，优选出了80个样本对常用的三种裂缝指标进行了标定，同时出一个缝洞孔隙指数；根据现有各井成象测井提取的裂缝密度、裂缝倾角和倾向信息，对区域裂缝的空间分布进行了分析，对进一步勘探开发有利地段提出了预测

头颈部动脉支架植入围手术期患者血清NETs标志物的动态变化（Dynamic Changes in Serum NETs Markers during the Perioperative Period in Patients Undergoing Head and Neck Arterial Stent Implantation）

目的 探讨头颈部动脉支架植入后血清中性粒细胞外陷阱（neutrophil extracellular traps，NETs）标志物瓜氨酸化组蛋白3（citrullinated histone 3，cit-H3）及髓过氧化物酶（myeloperoxidase，MPO）水平随时间变化的规律。 方法 前瞻性连续纳入因头颈部动脉粥样硬化性大动脉狭窄行支架植入术的患者，分别于术前空腹24 h内，术后6、12、24、48 h采集患者静脉血，测定血清cit-H3及MPO水平。采用经Greenhouse-Geisser校正的单因素重复测量方差分析，比较患者围手术期不同时间点血清cit-H3及MPO水平的动态变化趋势。根据支架植入部位（颅内 vs. 颅外）、支架植入数目（1个 vs. 2个）、责任血管是否为症状性狭窄，以及手术时脑梗死是否处于急性期（病程≤14 d），对血清cit-H3及MPO水平的变化进行亚组分析。 结果 本研究共纳入48例患者，平均年龄为（61.8±8.4）岁，男性42例（87.5%）。在整体患者中，血清cit-H3在术前及术后6、12、24、48 h的水平分别为（54.50±6.48）ng/mL、（56.73±6.50）ng/mL、（71.27±7.35）ng/mL、（53.53±17.35）ng/mL和（52.22±5.45）ng/mL；血清MPO在术前及术后6、12、24、48 h的水平分别为（25.45±6.67）ng/mL、（26.29±6.75）ng/mL、（28.28±7.68）ng/mL、（31.55±9.09）ng/mL和（28.68±7.61）ng/mL，两者术后水平均呈现先升高后降低趋势，整体差异均具有统计学意义（P=0.002；P=0.022）。颅外及颅内支架亚组、1个及2个支架亚组、症状性狭窄亚组及非急性期亚组的血清cit-H3水平均于术后12 h达到峰值。颅内支架亚组的血清MPO水平于术后12 h达到峰值，2个支架亚组、症状性狭窄亚组及非急性期亚组的血清MPO水平均于术后24 h达到峰值。 结论 头颈部动脉支架植入术后48 h内，血清NETs标志物cit-H3和MPO水平呈现先升高后恢复至术前水平的变化趋势，这种趋势在症状性狭窄患者中更显著。（Abstract: Objective To explore the dynamic changes over time in serum levels of neutrophil extracellular traps (NETs) markers—citrullinated histone 3 (cit-H3) and myeloperoxidase (MPO)—after head and neck arterial stent implantation. Methods Patients with atherosclerotic stenosis of the head and neck arteries who underwent stent implantation were prospectively and consecutively enrolled. Venous blood samples were collected from the patients within 24 hours of fasting before surgery, and at 6, 12, 24, and 48 hours after surgery to measure serum cit-H3 and MPO levels. One-way repeated measures analysis of variance with Greenhouse-Geisser correction was used to compare the dynamic changes in serum cit-H3 and MPO levels across different perioperative time points. Subgroup analyses of the changes in serum cit-H3 and MPO levels were conducted based on stent implantation site (intracranial vs. extracranial), number of stents implanted (1 vs. 2), whether the responsible vessel had symptomatic stenosis, and whether cerebral infarction was in the acute phase (disease duration≤14 days) at the time of surgery. Results A total of 48 patients were enrolled in this study with a mean age of (61.8±8.4) years, including 42 males (87.5%). Among all patients, the serum cit-H3 levels before surgery and at 6, 12, 24, and 48 hours after surgery were (54.50±6.48) ng/mL, (56.73±6.50) ng/mL, (71.27±7.35) ng/mL, (53.53±17.35) ng/mL, and (52.22±5.45) ng/mL, respectively. The serum MPO levels at the corresponding time points were (25.45±6.67) ng/mL, (26.29±6.75) ng/mL, (28.28±7.68) ng/mL, (31.55±9.09) ng/mL, and (28.68±7.61) ng/mL, respectively. Both markers showed a trend of increasing first and then decreasing, with statistically significant overall differences (P=0.002 for cit-H3; P=0.022 for MPO). In the extracranial and intracranial stent subgroups, the single and double stent subgroups, the symptomatic stenosis subgroup, and the non-acute phase subgroup, the serum cit-H3 levels peaked at 12 hours after surgery. The serum MPO levels peaked at 12 hours after surgery in the intracranial stent subgroup. However, in the double stent subgroup, the symptomatic stenosis subgroup, and the non-acute phase subgroup, the serum MPO levels peaked at 24 hours after surgery. Conclusions Within 48 hours after head and neck artery stent implantation, the serum levels of NETs markers cit-H3 and MPO showed an initial increase followed by a gradual return to preoperative levels. This trend was more pronounced in patients with symptomatic arterial stenosis.

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel

Prediction of Energy Resolution in the JUNO Experiment

International audienceThis paper presents the energy resolution study in the JUNO experiment, incorporating the latest knowledge acquired during the detector construction phase. The determination of neutrino mass ordering in JUNO requires an exceptional energy resolution better than 3% at 1 MeV. To achieve this ambitious goal, significant efforts have been undertaken in the design and production of the key components of the JUNO detector. Various factors affecting the detection of inverse beta decay signals have an impact on the energy resolution, extending beyond the statistical fluctuations of the detected number of photons, such as the properties of liquid scintillator, performance of photomultiplier tubes, and the energy reconstruction algorithm. To account for these effects, a full JUNO simulation and reconstruction approach is employed. This enables the modeling of all relevant effects and the evaluation of associated inputs to accurately estimate the energy resolution. The study reveals an energy resolution of 2.95% at 1 MeV. Furthermore, the study assesses the contribution of major effects to the overall energy resolution budget. This analysis serves as a reference for interpreting future measurements of energy resolution during JUNO data taking. Moreover, it provides a guideline in comprehending the energy resolution characteristics of liquid scintillator-based detectors

JUNO sensitivity on proton decay p → ν K + searches*

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this study, the potential of searching for proton decay in the $p\to \bar{\nu} K^+$ mode with JUNO is investigated. The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits suppression of the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar{\nu} K^+$ is 36.9% ± 4.9% with a background level of $0.2\pm 0.05({\rm syst})\pm$$0.2({\rm stat})$ events after 10 years of data collection. The estimated sensitivity based on 200 kton-years of exposure is $9.6 \times 10^{33}$ years, which is competitive with the current best limits on the proton lifetime in this channel and complements the use of different detection technologies