体育锻炼与文化成绩的相关联分析研究 ——以一分钟仰卧起坐为例

体育活动对青少年智育发展有积极的作用,但对学生的文化成绩影响还有待深入研究.研究分层抽样调查了广东省2499名小学生,通过测试体育运动项目一分钟仰卧起坐和文化成绩(语文、数学和英语),应用线性回归模型以校正性别,年龄,身高,体重,体重指数等因素的影响,在不同学校,多个年级的多个水平上,衡量体育运动能力对文化成绩的效应,并用meta分析和pooled分析综合评估其效应值的大小,最后采用偏相关系数进一步描述了一分钟仰卧起坐成绩与小学生文化成绩之间的关联.二者相关关系是客观存在的,这也暗示了鼓励和促进小学生积极参加体育锻练对于提高学习成绩的意义.     

基于外资渗透和部分私有化的混合多寡头研发投入研究

考虑到含有部分私有化的公共企业、纯私营企业、合资企业的混合三寡头市场竞争,构建了混合三寡头的两阶段博弈模型,得出了企业在研发投资时各个变量的均衡解以及最优解,并分析了私有化程度、合资企业的国内控股比例对研发投入、社会福利的影响。结果表明:私有化程度的提高将会使公共企业减少研发投入,私营企业和合资企业将会增加投入;合资企业的国内控股比例的增加将会提高最优社会福利。     

Introducing novel approaches for examining the variability of individuals’ physical activity

Tudor-Locke and colleagues previously assessed steps/day for 1 year. The aim of this study was to use this data set to introduce a novel approach for the investigation of whether individual’s physical activity exhibits periodicity fluctuating round a mean and, if so, the degree of fluctuation and whether the mean changes over time. Twenty-three participants wore a pedometer for 365 days, recorded steps/day and whether the day was a workday. Fourier transform of each participant’s daily steps data showed the physical activity had a periodicity of 7 days in half of the participants, matching the periodicity of the workday pattern. Activity level remained stable in half of the participants, decreased in ten participants and increased in two. In conclusion, the 7-day periodicity of activity in half of the participants and correspondence with the workday pattern suggest a social or environmental influence. The novel analytical approach introduced herein allows the determination of the periodicity of activity, the degree of variability in activity that is tolerated during day-to-day life and whether the activity level is stable. Results from the use of these methodologies in larger data sets may enable a more focused approach to the design of interventions that aim to increase activity.     

带p-Laplace算子的偏微分方程的Hartman-Wintner型定理

利用Riccati技术讨论了一类带p-Laplace算子的偏微分方程解的振动性质,得到了此类方程的Hartman-Wintner型振动定理.     

一阶线性偏微分方程求解的教学方法新探

通过常微分方程与偏微分方程之间的关系我们寻找到一种特殊的规范变换,通过此变换将复杂的偏微分方程的求解转化为可积分的偏微分方程(含参数的常微分方程)的求解.     

用偏最小二乘法提取石头口门水库水色信息

水体的高光谱数据在提供大量信息的同时，其波段间存在很高的相关性，常规的统计方法反演水质参数不但不能充分利用这些信息，并且也不能很好的去相关，而偏最小二乘回归分析可以较好的解决这一问题。因此本研究通过利用高光谱仪在石头口门水库进行反射光谱测量和同步水质采样分析，建立了叶绿素a和悬浮物含量的偏最小二乘回归模型。结果表明：该模型能较好的利用高光谱数据信息，各光谱波段自变量在最终模型中的系数大小在一定程度上较符合叶绿素a和悬浮物的光谱吸收、散射特性；通过与常规的比值模型、一阶微分模型进行对比，偏最小二乘回归模型明显优于前两者，其各决定系数均高于0.7，因此估测效果较理想，可用于内陆二类水体的水色信息提取。     

Biological and Biochemical Potential of Sea Snake Venom and Characterization of Phospholipase A<Subscript>2</Subscript> and Anticoagulation Activity

This study is designed to isolate and purify a novel anti-clotting protein component from the venom of Enhydrina schistosa, and explore its biochemical and biological activities. The active protein was purified from the venom of E. schistosa by ion-exchange chromatography using DEAE-cellulose. The venom protein was tested by various parameters such as, proteolytic, haemolytic, phospholipase and anti-coagulant activities. 80 % purity was obtained in the final stage of purification and the purity level of venom was revealed as a single protein band of about 44 kDa in SDS-polyacrylamide electrophoresis under reducing conditions. The results showed that the Potent hemolytic activity was observed against cow, goat, chicken and human (A, B and O positive) erythrocytes. Furthermore, the clotting assays showed that the venom of E. schistosa significantly prolonged in activated partial thromboplastin time, thrombin time, and prothrombin time. Venomous enzymes which hydrolyzed casein and gelatin substrate were found in this venom protein. Gelatinolytic activity was optimal at pH 5–9 and ¹H NMR analysis of purified venom was the base line information for the structural determination. These results suggested that the E. schistosa venom holds good promise for the development of novel lead compounds for pharmacological applications in near future.     

Student satisfaction with Canadian music programmes: the application of the American Customer Satisfaction Model in higher education

The purpose of this project is to empirically investigate several antecedents and consequences of student satisfaction (SS) with Canadian university music programmes as well as to measure students’ level of programme satisfaction. For this, the American Customer Satisfaction Model was tested through a survey of 276 current Canadian music students. The results indicate that customer satisfaction is strongly affected by programme quality, is slightly impacted by its perceived value but is not influenced by prior student expectations. Satisfaction strongly increases programme loyalty and positive word‐of‐mouth, marginally raises tuition change loyalty, and slightly decreases complaining behaviour. Contrary to expectations, tuition‐related constructs play only a minor role in the model. Therefore, money is a marginal factor in the educational environment; this empirically demonstrates the flaws underlying the premises of the students‐as‐customers metaphor. The resulting satisfaction index may facilitate the comparison among institutions. It was also found that the level of SS with Canadian music programmes was somewhat lower than those with services in other industries.     

青藏高原夏季降水与东亚、南亚夏季风相关程度的空间格局

基于CRU_TS4.0数据、东亚夏季风指数和南亚夏季风指数,使用偏相关分析方法,分析青藏高原1970-2014年间夏季（6-8月）降水的变化趋势及其对东亚夏季风（EASM）和南亚夏季风（SASM）响应的格局。结果表明：SASM与青藏高原夏季降水显著性相关的范围要明显大于EASM,SASM正相关区域位于青藏高原南部地区,负相关区域位于正相关区域外围、高大山体后部的高原西缘、中部和北部地区。EASM与高原夏季降水正相关区域集中分布于柴达木盆地,负相关区域面积较大,主要位于高原的中部和西部地区。     

小齿轮自调位装置设计研究综述

小齿轮自调位装置是小齿轮可绕自身中心在一定范围内沿球面转动,以适应大齿轮位置变化的一种新型自适应装置。此装置可以解决由于制造或安装误差引起的末级大小齿轮轴线不平行进而导致啮合不良的问题。本文阐述了小齿轮自调位装置的设计方法,从方式的选取,到结构型式的选取,最后针对最优的一种结构型式设计了三种方案,并进行分析比较,确定最优一种设计方案。