小波变换在信号奇异性检测中的应用

小波变换突破了传统傅里叶变换等信号处理方法的限制,在时域和频域上可同时对信号实现局部化处理,这更符合信号非平稳的变频带结构特征,因而在信号检测奇异性等方面具有广泛的应用价值。本文简要地介绍了小波应用在信号奇异性检测方面变换的基本原理,并通过仿真实验进行了验证。     

在华跨国公司的社会责任实践与强化问题探析

跨国公司的社会责任对自身的可持续发展及全球经济与贸易的增长都具有重要的意义。可部分进入中国市场的跨国公司却做出了忽略甚至缺失社会责任的事情。本文分析了这种现象的原因,并提出了若干促进在华跨国公司承担社会责任的措施。     

收益分配公平目标下的教育结构调整

以社会经济地位指数(SEI)作为衡量收益分配是否公平的一个替代性指标,利用课题组的调查数据将不同类型教育形式对收益分配的影响进行实证分析的结果表明,我国社会成员收益的两极分化情况较为严重。解决这一问题需要调整我国现行的教育结构,即完善就业前培训制度,实行普通高中后职业教育;加强专科层次的职业教育;大力发展本科层次的职业教育,试点更高层次的职业教育。     

Genomic diversity and post-admixture adaptation in the Uyghurs

Population admixture results in genome-wide combinations of genetic variants derived from different ancestral populations of distinct ancestry, thus providing a unique opportunity for understanding the genetic determinants of phenotypic variation in humans. Here, we used whole-genome sequencing of 92 individuals with high coverage (30–60×) to systematically investigate genomic diversity in the Uyghurs living in Xinjiang, China (XJU), an admixed population of both European-like and East-Asian-like ancestry. The XJU population shows greater genetic diversity, especially a higher proportion of rare variants, compared with their ancestral source populations, corresponding to greater phenotypic diversity of XJU. Admixture-induced functional variants in EDAR were associated with the diversity of facial morphology in XJU. Interestingly, the interaction of functional variants between SLC24A5 and OCA2 likely influences the diversity of skin pigmentation. Notably, selection has seemingly been relaxed or canceled in several genes with significantly biased ancestry, such as HERC2–OCA2. Moreover, signatures of post-admixture adaptation in XJU were identified, including genes related to metabolism (e.g. CYP2D6), digestion (e.g. COL11A1), olfactory perception (e.g. ANO2) and immunity (e.g. HLA). Our results demonstrated population admixture as a driving force, locally or globally, in shaping human genetic and phenotypic diversity as well as in adaptive evolution.     

Precision measurement of the Newtonian gravitational constant

The Newtonian gravitational constant G, which is one of the most important fundamental physical constants in nature, plays a significant role in the fields of theoretical physics, geophysics, astrophysics and astronomy. Although G was the first physical constant to be introduced in the history of science, it is considered to be one of the most difficult to measure accurately so far. Over the past two decades, eleven precision measurements of the gravitational constant have been performed, and the latest recommended value for G published by the Committee on Data for Science and Technology (CODATA) is (6.674 08 ± 0.000 31) × 10⁻¹¹ m³ kg⁻¹ s⁻² with a relative uncertainty of 47 parts per million. This uncertainty is the smallest compared with previous CODATA recommended values of G; however, it remains a relatively large uncertainty among other fundamental physical constants. In this paper we briefly review the history of the G measurement, and introduce eleven values of G adopted in CODATA 2014 after 2000 and our latest two values published in 2018 using two independent methods.     

运动记忆的研究(综述)

运用文献资料法,对国内外运动记忆研究的历程进行详细和系统的分析。以期了解运动记忆研究的历史过程、各种不同的研究方向,国内外对运动记忆研究的现状、热点及发展趋势,为进一步研究运动记忆等有关方面提供完备的前提资料。     

浅析体育教学模式的类型

对体育教学模式的类型、优劣及其归因进行分析,研究表明:体育教学目的任务不同,教学模式的着眼点也各不相同;即使教学目的任务相同,教学模式也会因教学指导思想的差异而有所区别。对教师学生地位、作用的认识不同是造成中国、前民德教学模式优劣与日本、美国基本相反的主要原因。     

中国乒乓球主力运动员马琳与马龙接发球技战术比较研究

通过文献研究、录像观察、数理统计等研究方法,从技术、线路、落点3个维度对马琳、马龙比赛中接发球特征与规律进行对比研究.结果表明:1)二者接发球控制性技术与进攻性技术使用率差异性均不显著.在具体技术运用上居前3位的技术马琳为:摆短、劈长、撇;马龙为劈长、摆短、反手拧.摆短、劈长差异性高度显著;反手拧差异性显著;其余技术差异性不显著.2)马琳接发球时反手、追身和正手三条线路分布较为均衡.马龙接发球线路控制反手过半,其次为追身和正手.二者在线路控制上,正手、追身和反手差异性均不显著.3)马琳接发球落点分布集中在中路近网短球、正手小三角和反手长球区域;马龙落点分布以长球为主,依次为反手长球、正手长球和中路长球.二者中路近网短球、正手近网短球使用率差异性高度显著;中路半出台球使用率差异性显著,其余区域落点分布差异性不显著.     

4周高强度间歇性训练对青少年竞走运动员运动能力的影响

目的:观察4周高强度间歇性训练(HIIT)对青少年竞走运动员肺活量、肌酸激酶(CK)、尿素(BU)、血红蛋白(HB)和运动成绩的影响.方法:14名男性竞走运动员平均分为两组,A组周一、周二、周四和周五下午采取HIIT,在功率自行车上进行120w全力蹬骑,运动时间为30s,控制心率在90%~100%最大心率(HRmax),组间休息3min,共进行8组.B组周一、周二、周四和周五下午均采取70%~80%HRmax的竞走耐力训练.A、B两组其他时间训练内容完全相同,主要为技战术训练和力量训练等.结果:经过4周高强度间歇性训练,A组运动员的肺活量、10km竞走成绩均显著高于B组,A组的BU水平显著低于B组,HB和CK两组之间无显著性差异.结论:4周高强度间歇性训练可有效提高竞走运动员心肺功能,降低BU,提高青少年竞走运动员的运动成绩.     

阳光体育背景下校园足球文化的作用

主要采用文献资料、专家访谈、逻辑分析等方法,理论实际联系,对我国目前开展的校园足球活动的概念、内涵、文化以及它与阳光体育的关系等等进行研究,旨在使人们正确认识我国校园足球开展的意义、目的和价值等等。