Can Board Secretaries Improve the Capital Market Efficiency——Evidence from the Perspective of Stock Price Synchronicity

利用2005~2011年中国A股上市公司8430个年度观察样本数据,从股价同步性视角实证分析了董事会秘书对资本市场效率的经验影响关系。结果发现:(1)与非金牌董秘相比,更加勤勉尽职的金牌董秘显著提高了上市公司的股价同步性;(2)随着证券分析师关注度的提高以及机构投资者持股比例的增加,金牌董秘对股价同步性的正向影响关系逐渐减弱。这些结果表明,董秘能够提升上市公司的信息透明度,进而提升资本市场效率。Using a sample of 8430 firm-year observations on Chinese A-share listed companies during the period of 2005-2011, we have empirically investigated how board secretary impact market efficiency from the perspective of stock price synchronicity.We find that compared with non-top secretaries, the top board secretaries that are more diligent and competent significantly increase listed companies' stock price synchronicity.However, this positive correlation gradually weakens as the analyst coverage and institutional ownership increases.These findings indicate that board secretary can improve listed companies' information transparency, thereby enhancing the market efficiency.国家自然科学基金青年项目(71202061); 面上项目(71572160

Effects of magnesium intake on expression of insulin receptor in type 2 diabetes rats

目的观察补镁对2型糖尿病大鼠胰岛素受体(InSulIn rECEPTOr,Ir)表达水平的影响。方法将高脂饲料喂养加链脲佐菌素注射方法诱发的2型糖尿病大鼠随机分为4个组,高、中、低剂量组在高脂饲料中分别加入氧化镁2000、1000、200Mg/kg(以镁离子计),糖尿病对照组只喂饲高脂饲料,正常对照组喂饲普通饲料。动物自由进食,连续4周,用葡萄糖氧化酶法测定空腹尾尖血的血糖含量,腹主动脉取血用放免法测定血清胰岛素含量,用免疫组化法测定胰腺和骨骼肌组织Ir表达水平。结果经IMAgE-PrO PluS图像分析,高剂量组的胰腺和骨骼肌组织中Ir表达水平分别为0.341±0.001和0.346±0.002,均较糖尿病对照组升高,而血糖水平则较糖尿病对照组降低,差异均有显著性意义(P<0.05)。结论镁补充可以提高2型糖尿病大鼠胰腺和骨骼肌组织中Ir的表达水平,降低空腹血糖水平。Objective To investigate the effects of magnesium intake on expression of insulin receptor in type 2 diabetes rats.Methods The models of type 2 diabetes rats were established by feeding with high-fat-diet and injecting streptozotocin(STZ).Rats were randomly assigned to four groups.The high-fat-diets were administrated magnesium at a dose of 2000(high magnesium group),1000(medium magnesium group)and200(low magnesium group).Model control group was only fed with high-fat-diet.Normal control group was fed with common diet.Rats ate freely for four weeks.Fasting blood glucose was detected by glucose oxidase method..Insulin was detected by radio-immunity method.The expression levels of IR of pancreas and skeletal muscle were detected by immunohistochemistry method.Results The immunohistochemistry pictures were analyzed by Image-Pro Plus.Compared with model control group,the expression levels of IR of pancreas and skeletal muscle were 0.341±0.001 and 0.346±0.002,increased and fasting blood glucose decreased significantly in high magnesium group(P<0.05).Conclusion Magnesium intake may increase the expression levels of IR of pancreas and skeletal muscle,and decrease fasting blood glucose in type 2 diabetes rats

The Influence of Magnesium Supplementation on Glucose and Lipid Metabolism of Rats with Type 2 Diabetes Mellitus

目的:研究镁补充对2型糖尿病大鼠糖脂代谢的影响。方法:将用高脂饮食联合链脲佐菌素(STz)方法诱发的2型糖尿病大鼠随机分为四个组,糖尿病对照组喂饲高脂饲料,高、中、低剂量组在高脂饲料中分别加入2000、1000、200 Mg/kg的镁(以镁离子计)。自由饮食喂养四周,处死动物。用放射免疫法测血清胰岛素(InS)水平、用葡萄糖氧化酶法测空腹血浆葡萄糖(fASTIng PlASMAgluCOSE,fPg),并计算胰岛素敏感指数(InSulIn SEnSITIVITy IndEX,ISI)。比色法检测糖化血红蛋白(glyCOSylATEd HEMOglObIn,HbA1C)。用全自动生化分析仪测高密度脂蛋白胆固醇(HIgH-dEnSITy lIPOPrOTEIn CHOlESTErOl,HdlC)、甘油三酯(TrIglyCErIdE,Tg)、总胆固醇(TOTAl CHOlESTErOl,TC)。结果:高剂量组的空腹血糖、空腹血清、糖化血红蛋白、甘油三酯、总胆固醇水平均较糖尿病对照组显著性降低(P<0.05),而高密度脂蛋白胆固醇、胰岛素敏感指数较糖尿病对照组显著性升高(P<0.05)。结论:镁补充可以提高2型糖尿病大鼠胰岛素敏感性,改善糖尿病大鼠的糖脂代谢情况。Objective: To investigate the effect of magnesium supplementation on glucose and lipid metabolism of rats with type 2 diabetes mellitus.Method: Rats with type 2 diabetes mellitus were induced with high fat diet and intraperitoneal injection with small dose of STZ,then they were divided into 4 groups randomly: high,medium,low magnesium supplementation groups and diabetes mellitus control group.Diabetes mellitus control group was feed with high-fat feed only.The dosage added in high-fat feed of the high,medium,low magnesium supplementation groups are 2000,1000,200 mg/kg(measured by Mg2+).All the rats ate and drunk freely.All rats were killed after four weeks.The serum insulin(Ins) level were tested with radiation immune method,fasting plasma glucose(FPG)were mea-sured with glucose oxidase method,and calculation the insulin sensitivity index(ISI).Glycosylated hemoglobin(HbA1c) was measured by chromatometry.High-density lipoprotein cholesterol(HDLC),triglyceride(TG),total cholesterol(TC) were measured by automatic biochemical analyzer.Results: FPG,Ins,TG,TC levels of high dose group was significantly lower compared with that in the diabetic control group(P<0.05),while HDLC,ISI increased significantly compared with that in the diabetic control group(P<0.05).Conclusion: Magnesium supplement can improve insulin sensitivity,improve glucose and lipid metabolism in type 2 diabetic rats

INFLUENCE of MAGNESIUM SUPPLEMENTATION ON INSULIN RESISTANCE AND THE INFINITY of RECEPTOR IN RATS WITH TYPE 2 DIABETES MELLITUS

目的观察镁补充对2型糖尿病大鼠胰岛素受体亲和力的影响。方法将用高脂饮食联合链脲佐菌素(STz)方法诱发的2型糖尿病大鼠随机分为4个组,糖尿病对照组喂饲高脂饲料,高、中、低剂量组在高脂饲料中分别加入2000、1000、200Mg/kg的镁(以镁离子计)。每周检测空腹血糖1次。自由饮食喂养4 W,处死动物。用放射性受体分析法测肝细胞胰岛素受体亲和力、放射免疫法测血清胰岛素(InS)水平、比色法检测糖化血红蛋白(HbA1C)和血浆丙二醛(MdA)、葡萄糖氧化酶法测空腹血浆葡萄糖(fPg),并计算胰岛素敏感指数(ISI)和抵抗指数(IrI)。结果高剂量组的高亲和力胰岛素受体结合常数(k1)为(4.76±0.08)x108l/MOl,低亲和力胰岛素受体结合常数(k2)与结合容量(r2)分别为(1.10±0.14)x106l/MOl,(8.49±0.43)x1013/Mg蛋白,均较糖尿病对照组显著性升高(P<0.05)。补镁第3 W开始高剂量组空腹血糖较糖尿病对照组显著性降低,高剂量组的胰岛素敏感指数较糖尿病对照组显著性升高,而胰岛素抵抗指数则显著性降低。结论镁补充可以提高2型糖尿病大鼠胰岛素受体亲和力,降低胰岛素抵抗。Objective To observe the influence of magnesium supplementation on the infinity of insulin receptor in rats with type 2 diabetes mellitus.Method The rats with type 2 diabetes mellitus were induced with high fat diet and intraperitoneal injection with small dose of STZ.They were randomly divided into 4 groups,i.e.high,medium,low magnesium(2000,1000,200 mg/kg Mg2+) supplementation groups and diabetes mellitus control group.FPG was measured weekly.All rats were killed after 4 w,and liver cells were tested with radiation receptor analysis of their combination constants and combined capacity.The serum insulin(Ins) level was determined with radioimmunoassay.FPG,glycosylated hemoglobin(HbA1c) and plasma malondialdehyde(MDA) were also measured,and insulin resistance index(IRI) and insulin sensitivity index(ISI) were calculated.Results: High affinity insulin receptor combination constant(K1),low affinity insulin receptor combination constant(K2) and combination capacity(R2) of high dosage group were(4.76±0.08)×108 L/ mol,(1.10±0.14)×106 L/ mol,(8.49±0.43)×1013 /mg protein respectively,significantly increased than those in diabetes mellitus control group(P<0.05).FPG was decreased since the 3th week during magnesium supplementation.The insulin sensitivity index(ISI) of high dosage group was significantly increased than that of model control group,but insulin resistance index(IRI) was decreased.Conclusion Magnesium supplementation could improve insulin receptor affinity and reduce insulin resistance in type 2 diabetic rats

注意缺陷多动障碍的遗传学和认知内表型研究概况（综述）

注意缺陷多动障碍（Attention Deftcit Hyperactivity Disorder，ADHD）是儿童期常见、早期发生的认知、行为发展性的精神障碍，其主要特征为与年龄不相称的注意力不集中、多动和冲动行为。学龄期儿童患病率为4-12％．男女比例为3～9：1，其中50％～80％可持续至青年，30％-50％持续到成年。美国精神疾病诊断和统计手册第四版（DSM—IV）将其分为注意缺陷为主型、多动一冲动为主型和混合型三种亚型。ADHD是由遗传学、生物学、环境和家庭压力共同作用形成的一种多基因遗传性疾病。本文根据ADHD的遗传学研究及认知理论模型，综述其可能的认知内表型研究

The Puzzle of Low Price Premium Effect: Evidence from China

本文主要研究低价股的溢价异象,并从行为金融学视角分析指出股票的名义价格幻觉是造成低价股溢价效应的重要原因。基于1999-2014年中国A股上市公司175,736个月度样本数据的实证分析表明,中国资本市场存在显著持续的低价股溢价现象,而且上市公司的散户规模越大,低价股的溢价效应越强,证实了本文的理论观点和预期。与此同时,我们发现机构投资者持股、证券分析师关注、卖空机制等都有利于降低低价股的溢价程度,从而帮助资本市场矫正误定价和资源错配问题。进一步,我们还发现上市公司的管理者还会通过发放股票股利以利用投资者的名义价格幻觉和迎合投资者对低价股的偏好,从而实现市值管理的目的。本文的研究结论对于揭开中国资本市场低价股的溢价之谜和提高资本市场的定价效率都具有重要的实践启示和政策参考。In this paper, we focus on the low price premium effect and suggest nominal price illusion is one of the main causes from behavioral finance perspective. Using a dataset which contains 175,736 firm - month observations of Chinese A - share listed companies from 1999 to 2014, we document that there is indeed a superior performance attached to low price stocks, i. e. , the low price premium effect. What＇ s more, the bigger the size of individual investors, the stronger the low price premium effect, which further supports our theoretical expectation. Meanwhile, we find evidence that institutional ownership, security analyst coverage, and short sales can all significantly alleviate the low price premium effect, thereby contributing to the rectification of mispricing and resource misallocation in capital markets. Furthermore, we find that for the sake of maximizing their firms＇ market value, firm managers would take advantage of investors＇ particularly individual investors＇ nominal price illusion to carter those investors＇ preference for relatively low price stocks through issuing stock dividends. Our findings would give helpful insights for market operations and policy making into revealing the puzzle of low price premium effect and improving pricing efficiency in China.国家自然科学基金项目(71202061和71572160)；福建省高等学校新世纪优秀人才支持计划(2015年)；福建省高校杰出青年科研人才培育计划(2015年)的资助

磁盘轴向偏摆信号的计算机处理

本文讨论了磁盘轴向偏摆信号处理的原则和方法,阐述了高速A/D接口设计原则。在多次采样的前提下,对所测信号进行了加权滤波和FFT分析,设计了数据采集,数据处理及绘图程序,得到了磁盘轴向偏摆的位移曲线,速度曲线及加速度曲线,为磁盘轴向偏摆信号的计算机处理提供了一套完整的方法