Meeting guidelines for physical activity,muscle strength,and sleep lowers mortality risk:Commentary on: "Associations between aerobic and musclestrengthening physical activity,sleep duration,and risk of all-cause mortality:A prospective cohort study of 282

<正>In 2022, Duncan et al.¹ published results from an investigation of the combined effects of moderate-to-vigorous aerobic exercise(AER), muscle-strengthening activities(MSA), and sleep durations on the risks for all-cause mortality in 282,473 U.S. adults aged 18—84 years.     

Glacial expansion of cold-tolerant species in low latitudes: megafossil evidence and species distribution modellingOA

<正>The Pleistocene was a time of repeated glaciations that severely affected the land biota over large areas of Eurasia and North America. Drastic climatic fluctuations during the Pleistocene drove largescale extinctions, migrations and diversification in plant and animal populations.These dramatic processes had a strong impact on the distribution of modern flora and fauna.     

Epidemiology of insertional and midportion Achilles tendinopathy in runners:A prospective cohort study

Background:Achilles tendinopathy(AT) is a common problem among runners.There is only limited evidence for risk factors for AT,and most studies have not defined the AT subcategories.No study has compared the incidence and risk factors between insertional AT and midportion AT,though they are considered distinct.This study aimed to assess incidence and risk factors of AT based on data from a large prospective cohort.The secondary aim was to explore differences in risk factors between insertional an...     

求解震荡型矩阵函数的一类有效数值算法

震荡型矩阵函数主要出现在求解二阶半线性常微分方程的ERKN积分中,其计算效率直接决定了这类积分的计算效率.本文设计了修正的缩放四次方方法求解震荡型矩阵函数,基于后验误差分析理论提取了关键参数.数值实验表明了该方法的有效性和稳定性.     

深度信念以及信念和信仰的相对作用

“深度信念”是怀特海文稿中的关键概念。在怀特海有机哲学看来,动机、方法和意义是一个整体。他懂得要在深层次上探查人类追求意义及理解的倾向,进而揭示“追求”行为中的创造张力。深度信念就是这种深层次的动力。深度信念不同于各种各样起源于文化传统的信仰或偶发的信念,它不像后者那样可能失去。怀特海认为,在个人经验中,某一个信念的失去更可能是“无限性激励下的有限性”,是某种“超越的内在性”,“朝向更精美细致的结果”。深度信念促成了精神的冒险,是人类固化成就中不可抹去的最富锐气的因素,是人的呈现。     

商品个性标志的定义及其在美国流行文化中的角色

在过去的一个多世纪,商品的个性标志一直是美国人钟爱的广告工具。各种各样被广告商作为传播体系的＂会说话的动物＂和＂会跳舞的产品＂已悄无声息地蔓延在美国的流行文化中。1982年,有人在做调查后发现,凡是商品特征明显的广告,在改变品牌偏好的能力上要比同行业其他品牌强。这一点表明社会正在接收商品个性标志这样的讯息。然而,尽管商品个性标志的运用在广告商和消费者中大受欢迎,却几乎被完全遗忘在广告和流行文化研究的角落。本文将从相关文学的角度解析什么是商品个性标志,以及其如何运用在现代广告业中,并与消费者进行交流。     

中国武术资源开发探析

中国武术博大精深,在绵延千年的发展历程中积累了丰富的资源,处于新的历史时期的中国武术,如何更好的发挥其资源的优势作用,使其得到合理开发是武术界面临的一个问题,通过查阅大量的文献资料和在北京、河南等地的实地考察,结合武术资源的特性,根据武术资源的分类体系,对其现状开发中存在问题进行分析,提出了合理开发的具体措施。     

Comparison of two Actigraph models for assessing free-living physical activity in Indian adolescents

This aim of this study was to compare the new Actigraph (GT1M) with the widely used Model 7164. Seven days of free-living physical activity were measured simultaneously using both the Model 7164 and GT1M in 30 Indian adolescents (mean age 15.8 years, s = 0.6). The GT1M was on average 9% lower per epoch than model 7164, thus a correction factor of 0.91 is suggested for comparison between the two monitors. The differences between monitors increased in magnitude with intensity of activity (P < 0.001) but remained randomly distributed (r = 0.01, P = 0.96). No significant difference was observed between monitors for time spent in moderate (P = 0.31) and vigorous (P = 0.34) physical activity when using the same epoch length. The Model 7164 classified less time as sedentary (P < 0.001) and more time as light-intensity activity (P < 0.001) than the GT1M. In conclusion, data from the GT1M can be compared with historical data using average counts per minute with a correction factor, and the two models might be comparable for assessing time spent in moderate to vigorous physical activity in children when using the same epoch length.     

The influence of lower limb amputation level on the approach in the amputee long jump

In this study, we investigated the adjustments to posture, kinematic and temporal characteristics of performance made by lower limb amputees during the last few strides in preparation for long jump take-off. Six male unilateral trans-femoral and seven male unilateral trans-tibial amputees competing in a World Championships final were filmed in the sagittal plane using a 100-Hz digital video camera positioned so that the last three strides to take-off were visible. After digitizing using a nine-segment model, a range of kinematic variables were computed to define technique characteristics. Both the trans-femoral and trans-tibial athletes appeared to achieve their reduction in centre of mass during the flight phase between strides, and did so mainly by extending the flight time by increasing stride length, achieved by a greater flexion of the hip joint of the touch-down leg. The trans-tibial athletes appeared to adopt a technique similar to that previously reported for able-bodied athletes. They lowered their centre of mass most on their second last stride (-1.6% of body height compared with -1.4% on the last stride) and used a flexed knee at take-off on the last stride, but they were less able to control their downward velocity at touch-down (-0.4 m x s(-1)). Both this and their restricted approach speed (8.9 m x s(-1) at touch-down), rather than technique limitations, influenced their jump performance. The trans-femoral athletes lowered their centre of mass most on the last stride (-2.3% of body height compared with -1.6% on the second last stride) and, as they were unable to flex their prosthetic knee sufficiently, achieved this by abducting their prosthetic leg during the support phase, which led to a large downward velocity at touch-down (-0.6 m x s(-1)). This, combined with their slower approach velocity (7.1 m x s(-1) at touch-down), restricted their performance.     

Validation of an integrated experimental set-up for kinetic and kinematic three-dimensional analyses in a training environment

Biomechanical analyses using synchronized tools [electromyography (EMG), motion capture, force sensors, force platform, and digital camera] are classically performed in a laboratory environment that could influence the performance. We present a system for studying the running sprint start that synchronizes motion capture, EMG, and ground reaction force data. To maximize motion capture (Vicon 612 with six cameras), a special dim environment was created in the stadium. "Classical" tools were combined with "purpose-built" tools intended to analyse the different aspects of movement. For example, a synchronization system was built to create a common time-base for all data recordings and a portable EMG system was synchronized by a cable that was "disconnected" by the athlete's movement out of the blocks. This disconnection represented an independent event recorded by different tools. A "gap" was measured for some sprint start events between kinetic and kinematic (motion capture) data. Calibration results, measurements of time "gap", and duration of the independent event were used to validate the accuracy of motion capture and the synchronization system. The results validate the entire experimental set-up and suggest adjustment values for motion capture data. This environment can be used to study other movements and can easily be applied to several sports.