DEVELOPMENT AND EVALUATION OF A NOVEL TAEKWONDO CHEST PROTECTOR TO IMPROVE MOBILITY WHEN PERFORMING AXE KICKS

The axe kick, in Olympic style taekwondo, has been identified as the most popular scoring technique aimed to the head during full contact competition. The first purpose of this study was to identify and investigate design issues with the current World Taekwondo Federation approved chest protector. A secondary purpose was to develop a novel chest protector addressing the identified design issues and to conduct a biomechanical analysis. Fifteen male elite Taekwondo players were selected to perform three different styles of the axe kick, i.e., front, in-out, and out-in axe kick five times each for a total of 45 kicks. Two-way repeated measures ANOVA showed significant differences between the novel and existing chest protector conditions for vertical height of the toe, downward kicking foot speed, hip flexion angle and ipsilateral shoulder flexion extension range of motion (ROM) (p < 0.05). There were no significant differences between the control condition (no chest protector) and the novel chest protector condition for these variables (p > 0.05). These results indicate that the novel chest protector interferes less with both the lower and upper limbs during the performance of the axe kick and provides a more natural, free-moving alternative to the current equipment used.     

BIOMECHANICS OF HEAD INJURY IN OLYMPIC TAEKWONDO AND BOXING

Objective

The purpose was to examine differences between taekwondo kicks and boxing punches in resultant linear head acceleration (RLA), head injury criterion (HIC15), peak head velocity, and peak foot and fist velocities. Data from two existing publications on boxing punches and taekwondo kicks were compared.

Methods

For taekwondo head impacts a Hybrid II Crash Dummy (Hybrid II) head was instrumented with a tri-axial accelerometer mounted inside the Hybrid II head. The Hybrid II was fixed to a height-adjustable frame and fitted with a protective taekwondo helmet. For boxing testing, a Hybrid III Crash Dummy head was instrumented with an array of tri-axial accelerometers mounted at the head centre of gravity.

Results

Differences in RLA between the roundhouse kick (130.11±51.67 g) and hook punch (71.23±32.19 g, d = 1.39) and in HIC15 (clench axe kick: 162.63±104.10; uppercut: 24.10±12.54, d = 2.29) were observed.

Conclusions

Taekwondo kicks demonstrated significantly larger magnitudes than boxing punches for both RLA and HIC.     

样本对小麦遗传距离与杂种优势关系的影响

本文以10个小麦品种和按双列杂交配制的45个组合为材料,研究了样本容量和样本的数据结构对遗传距离与杂种优势关系的影响．结果表明：（1）当样本容量较小时,遗传距离与产量杂种优势的关系为不相关;随着样本容量的增加,遗传距离与产量杂种优势的关系有由不相关,到Y=axe～bx(a＞0,b＜0）,Y=ax～be～cx（a、b＞0,c＜0）相关的变化趋势．（2）当样本的数据结构较差时,需较大样本容量,才能真实反映遗传距离与产量杂种优势的关系．     

中国城乡汉族儿童六年间(1979年—1985年)身高和躯干比例的变动趋势

本文以1979年和1985年两次全国体质调研的结果为基础材料,对我国汉族儿童在身高加速现象方面的城乡差别以及躯干比例在身高加速生长中的变动进行了分析,初步得出如下结论：(1) 6年间城乡汉族儿童的身高加速生长、发育提前;(2) 乡村儿童身高增加和身高及坐高发育高峰年龄提前的幅度大于同性别城市儿童;(3) 青春期儿童的身高和躯干比例变化较大;(4) 儿童身高和躯干比例的变化主要是成熟节律提前造成的。     

DEVELOPMENT AND ORGANIZATION OF THE PRIMARY VASCULAR SYSTEM IN POPULUS DELTOIDES ACCORDING TO PHYLLOTAXY

An actively growing cottonwood bud was embedded in epon-araldite and serially sectioned at 2 μm. The sections were analyzed microscopically with the optical shuttle system of Zimmermann and Tomlinson, and all data were quantitatively recorded relative to the apex and to leaf plastochron index (LPI). Analysis of the sections revealed an acropetally developing procambial system organized according to a precise phyllotaxy. Six procambial strands could be recognized and followed long before the leaf primordia that they would enter were evident at the apex. Origin of these strands coincided with developmental events both in the parent trace and its primordium and in the antecedent leaf on the same orthostichy. Once a primordium and its trace attained a certain stage of development, trace bundles began to develop basipetally from the primordium base. These trace bundles appeared to be the earliest progenitors of wood formation in cottonwood. It was concluded that the concept of residual meristem and its corollary, the hypothesis that acropetally developing procambial strands determine the inception sties of new primordia, apply to the cottonwood apex.     

水面和水下长航对艇员肠道菌群影响的比较及意义探讨

比较研究和水下两种长期航行条件对航艇和核潜艇艇员肠道菌群的影响并对其意义进行初步探讨。结果显示两种长航条件均对人体肠道菌群产生显著影响,可打破肠道微生态平衡,但两者所致的肠道菌群构成变化的特点不同。提示不同长航条件可造成不同的微生态失调,需区别对待。     

厚颌鲂含肉率及生化成分的分析

研究了长江上游特有鱼类厚颌鲂的含肉率及其肌肉生化成分和能值。结果表明 :厚颌鲂的含肉率为72 72 % ;其肌肉生化成分 (鲜重百分比 ) :水分含量为 79 2 6%、蛋白质 16 82 %、脂肪 2 10 %、灰分 1 0 8%、无氮浸出物 0 73 %、比能值 4 93KJ/g及E/P2 9 3 3KJ/g。肌肉生化成分含量与体长变化无明显关系。经单因素方差分析 5— 6月份样品与 10月份样品在脂肪和无氮浸出物含量上有显著差异 (P <0 0 5)。肌肉中含有 17种氨基酸 ,总量为69 54% (干重百分比 ) ;9种人体必需氨基酸总量是 3 3 0 7% ,占氨基酸总量比例为 47 55% ;必需氨基酸指数 (EAAI)是 61 75。缬氨酸和异亮氨酸为限制性氨基酸 ;四种鲜味氨基酸含量为 5 85% (鲜重百分比 )。     

油菜叶片蛋白质组对机械损伤应答的初步分析

 植物在对抗昆虫的长期进化过程中形成了自我防御机制,能够产生特异的抗性蛋白来应对昆虫的取食。该文用机械损伤模拟害虫取食,研究和 对比了油菜(Brassica napus cv. Westar)在机械损伤前后可溶性总蛋白的含量变化并试图通过蛋白质组学技术来检测可能发生变化的蛋白质。 蛋白质定量检测发现,同一植株同一叶片损伤前后可溶性总蛋白含量差异显著,损伤后蛋白表达量增高。 蛋白质双向凝胶电泳及其差异显示分 析损伤前后的蛋白质组,表明有8个蛋白质点发生明显的上调或下调。选择其中2个差异蛋白点经过MALDI-TOF质谱鉴定,它们分别是Rubisco小 亚基前体、果糖-1,6-二磷酸醛缩酶和粪卟啉-3-氧化酶,这些蛋白质可能在油菜叶片应答机械损伤过程中对维持植物的生理功能起到重要作用 。     

黑尾近红鲌含肉率及肌肉营养成分分析

测定了长江上游特有鱼类黑尾近红的含肉率及其肌肉生化成分和能值。结果表明 :黑尾近红的含肉率为 70 74 % ;其肌肉生化成分 (鲜重百分比 )水分含量为 80 97%、蛋白质 15 92 %、脂肪 1 11%、灰分 1 0 1%、无氮浸出物 0 99%、比能值 4 37kJ/g及E/P 2 7 4 5kJ/g。肌肉生化成分含量与体长变化无明显关系。肌肉中含有 17种氨基酸 ,总量为 6 9 0 7% (干重百分比 ) ;9种人体必需氨基酸总量是 34 81% ,必需氨基酸占氨基酸总量比例为5 0 39% ;四种鲜味氨基酸含量为 2 6 94 % ;必需氨基酸指数 (EAAI)是 6 3 6 4。缬氨酸 ,苏氨酸和异亮氨酸为限制性氨基酸。     

上海塘桥地区鼠类群落演替与住房结构变迁关系的分析

近年来,上海市随着市政建设的迅速扩大与改造,人类各种经济生产活动的加强及人口的增加,城市环境日益发生巨大变化。在城市化的进程中,城市里野生动物的组成及其数量也随之发生变动,例如与人伴生的有害鼠类。     

中国新石器时代居民体质类型及其承继关系

运用数理统计方法把我国新石器时代居民分为华南、华北两大类群,其中华北类群又可分为三个小类群。在人类发展过程中,南、北两群间及华北各类群间都发生过血缘混杂的过程。运用数理统计方法也可把我国旧石器晚期人类——山顶洞人和柳江人在体质特征上与我国新石器时代各组居民明显地区别开来。山顶洞人和柳江人分别代表我国旧石器晚期南北两个不同的地方类型。我国新石器时代居民的所谓澳大利亚—尼格罗人种或南亚人种特点可以追溯到我国旧石器时代晚期人类——柳江人、山顶洞人,这些特点是我国新石器时代组人类固有的特点,只不过在不同的类群中表现有所差异而已。     

CORRELATION OF PAIRWISE GENETIC AND GEOGRAPHIC DISTANCE MEASURES: INFERRING THE RELATIVE INFLUENCES OF GENE FLOW AND DRIFT ON THE DISTRIBUTION OF GENETIC VARIABILITY

Attempts to relate estimates of regional F_ST to gene flow and drift via Wright's (1931) equation F_ST ≈ 1/ (4Nm + 1) are often inappropriate because most natural sets of populations probably are not at equilibrium (McCauley 1993), as assumed by the island model upon which the equation is based, or ineffective because the influences of gene flow and drift are confounded in the product Nm. Evaluations of the association between genetic (F_ST) and geographic distances separating all pairwise populations combinations in a region allows one to test for regional equilibrium, to evaluate the relative influences of gene flow and drift on population structure both within and between regions, and to visualize the behavior of the association across all degrees of geographic separation. Tests of the model using microsatellite data from 51 populations of eastern collared lizards (Crotaphytus collaris collaris) collected from four distinct geographical regions gave results highly consistent with predicted patterns of association based on regional differences in various historical and ecological factors that affect the amount of drift and gene flow. The model provides a prerequisite for and an alternative to regional F_ST analyses, which often simply assume regional equilibrium, thus potentially leading to erroneous and misleading inferences regarding regional population structure.     

GENETIC FINGERPRINT-INFERRED POPULATION SUBDIVISION AND SPATIAL GENETIC TESTS FOR ISOLATION BY DISTANCE AND ADAPTATION IN THE COASTAL PLANT LIMONIUM CAROLINIANUM

This paper examines two wild populations of Limonium carolinianum for population genetic subdivision and spatial patterns of genetic variation in an attempt to simultaneously test for both the action of local adaptation to tidal gradients and isolation by distance (IBD). A VNTR (variable number of tandem repeats) genetic “fingerprinting” marker was used to infer relatedness among mapped plants in two populations. Band sharing within and between populations estimated F'_ST, an approximate measure of F_ST. Regression models were used to analyze the relationship between band sharing and spatial separation in tidal elevation and horizontal distance, as well as the relationship of fecundity differences with band sharing and spatial distance. Populations differed in band size frequency distributions and mean number of bands per profile and, therefore, likely differed in effective population size. F'_ST was estimated at 0.0678 and was significantly greater than F'_ST among randomly constructed subpopulations. Band sharing decreased 0.13% per meter in one population but showed no significant relation to distance in the other. In the population with significant IBD band sharing increased with increasingly different tidal elevation, contrary to an adaptive hypothesis, possibly due to directional gene flow or drift. Deme sizes were approximately 25 meters and greater than 100 meters, spanning larger areas than the entire environmental gradient. Fecundity differences were not associated with spatial parameters or band sharing. Unequal potential maternal fecundity measured as variance in number of seeds per maternal family was a significant source of genetic sampling variance. The VNTR marker employed is capable of detecting adaptation as identity by descent in ecological time and is an appropriate method for estimating the net evolutionary fate of polygenic traits. The results show that the net balance between selection along an environmental gradient and the effects of IBD and unequal maternal fecundity favor genetic differentiation by random processes in populations of Limonium.