儿童的惯性－惯量特征及其生长

本文应用排水法得到儿童肢体沿长轴的体积分布函数。根据关于人类肢体体积－质量的假定，肢体的质心、转动惯量及旋转半径等动力学常数可由前述的体积分布函数中求出。本文结果显示，部分力学参数与儿童的生长有着密切的联系，并受到性别的影响。因此，这些参数可以用来作为儿童的生长指标。以往数据的离散性表明，无论从系统上或技术上，这一领域都有许多工作要做。     

儿童身高生长追踪研究

以北京市106名儿童为样本 ,为研究各年龄生长速度的集中趋势、变异状况以及与生长速度有关的参数 ,追踪观察这些儿童自6、7岁至 18岁时共12年的身高变化 ,并做有关参数分析。报告了各年龄组身高生长速度的均值及标准差 ,该组儿童身高生长突增开始年龄 (男10.73±1 .12岁 ,女 9.00± 1.18岁 )及速度 (男4.51± 0.65cm/年 ,女 4.95± 0.79cm/年 ) ;身高生长高峰发生年龄 (男 1 3.0 7±1.08岁 ,女11.32± 1.32岁 )及速度高峰值 (男10 .01± 1.59cm/年 ,女8.13± 1.03cm/年 ) ;以及生长突增结束年龄 (男16.18± 1.02岁 ,女 13.96± 1.09岁 )。分析了最终身高与生长突增有关指标的相关关系。     

中国汉族儿童生长的长期趋势

本文报告了中国北京、天津、济南、哈尔滨、沈阳、长春、上海、南京、杭州、武汉、广州及成都等12个城市汉族7—18岁儿童生长的长期趋势。 50年代至今,汉族儿童生长的长期趋势是明显的,30年来同年龄儿童身高每10年增长2.66(男)、2.40(女)厘米,体重每10年增长1.64(男)、1.14(女)公斤,近10年来的增长最为显著。生长突增高峰年龄大都提前1—2年。北京、上海、南京、广州、杭州等五所城市自30年代至今,生长长期趋势也是明显的,半个世纪来,每10年增长值,男童身高为1.12—2.66厘米,体重为0.56—1.29公斤,女童身高为1.42—2.67厘米,体重为0.65—1.18公斤。     

济南市社会经济发展与儿童少年生长的长期变化

本文分析了１９５６－１９９５年济南市７－１８岁儿童少年生长发育的变化趋势。３９年间,男女生身高平均增长值分别为１０．８３ｃｍ的９．４７ｃｍ,平均每１０年增长２．７６８ｃｍ和２．４３ｃｍ;男一体重增长值分别为９．１９ｋｇ和５．１２ｋｇ,平均每１０年增长２．３６ｋｇ和１．３１ｋｇ。将不同年代人均工业总产值作对数转换后发现,与各年龄儿童少年身高、体重的发育水平呈明显的直线正相关,不同年代人均工业总产值的     

北京市幼儿园2—6岁儿童生长情况

1985年5月—8月,作者对北京市幼儿园833名2—6岁儿童进行了人体测量调查,并对所获得的数据进行了统计分析。结果表明2—6岁儿童身高增长较快,平均每年增加70毫米,身体各部分的长度变化基本与身高的增长相协调;围度的变异范围大于长度的变异范围。同1975年调查结果相比,儿童的体重、身高、胸围等项目数值都有所增加,但身高的增加速度已减慢。     

南京地区771名汉族儿童面部特征的调查

本文对南京地区771名汉族儿童的头面部16项指标及有关指数进行了测定。小儿面部容貌有随年龄变化而变化的特点。虽然小儿头型与成人一样,以短头型(包括过短头型)为主,但面型、鼻型与成人有显著区别,即面型以超阔面型和阔面型为主,中面型少见,狭面型更少;鼻型也多为阔鼻型。     

生长模型的误差函数及其数学特征

生长曲线是估计动物年龄的重要方法之一,在野生动物生态学中,动物的体重往往被用作估计动物年龄的主要指标。然而,在动物体重测定过程中经常会出现一些偏差。例如,动物的日常活动（ 进食、饮水、排泄等）通常会引起动物体重的变化,这样在不同时间测定动物的体重就会产生偏差;此外,在测定动物体重的过程中,我们往往称量到一定的精确度。这些偏差将直接导致对动物年龄的估计误差。本文分析了4种常见生长模型（Logistic、Gompertz、Bertalanffy、Richards)的误差函数的数学特征。结果表明,由动物日常活动导致的年龄估计误差在动物的幼龄阶段为量小,而由称量精确度导致的年龄估算误差在生长曲线的拐点处为最小。     

鄱阳湖黄鳝的生长特征

以基舌骨和脊椎骨作为年龄鉴定的材料,研究了鄱阳湖黄鳝(Monopterus albus)种群的生长特征.结果表明,种群的年龄结构分别为:雌性1～5龄,雄性2～6龄,2～5龄为黄鳝性别的过渡期(间性).2～4龄为优势年龄组,占渔获物的89.75%,相对应的体长为30～50 cm,体重为30～120 g.体长(L)与体重(W)的关系为:W=0.000 4L3.2601(♀);W=0.001 4L2.9008(∮).按生长指标值分析,阶段生长可以明显地划分为两个时期,即2龄前的生长迅速期和2龄后的生长稳定期.拟合的Von Bertalanffy生长参数分别为雌性L∞=78.5 Cm,k=0.174 02/y,t0=-1.203 2 Y,W∞:602.01 g;雄性L∞=102.3 cm,k=0.118 45/y,t0=-1.310 1 Y,W-=947.32 g;生长特征参数分别为ψ=3.030 3(♀)和ψ=3.093 4(∮);雌雄个体生长差异显著.     

长治市幼儿园4—5岁儿童四季生长情况

作者对山西省长治市幼儿园1980和1981年出生的216名儿童(男125、女91),在1985年四季生长的情况进行了测量和统计分析。结果表明,男童年均身高增长6.12厘米,体重增长2.49公斤;女童年均身高增长5.65厘米,体重增长2.35公斤。各季身高和体重增长值经F检验,季节差异均非常显著(p<0.01)。一年内最佳生长季节为秋季,同其它三季比较,经Dunnett检验,只有春季男女儿童身高增长和冬季女童体重增长与秋季相比,差异不显著(P<0.05)。其余各季增长同秋季比较,差异均非常显著(P<0.01)。     

胡杨枝芽生长特征及其展叶物候特征

以5个不同发育阶段的胡杨(Populus euphratica Oliv.)个体为研究对象,观测记录了枝芽展叶物候、枝芽生长特征和叶形变化的空间分布规律。结果表明:不同发育阶段的胡杨个体以及同一个体树冠的不同层次,其枝芽生长及其展叶物候期表现出不同的时空特征。随着树龄的增加和树冠层次的增高(由基向顶),当年新生枝条长度、枝条叶片数和叶形指数逐渐减小,但叶面积和叶片干重逐渐增大。5个不同发育阶段胡杨个体均表现出展叶物候始于树冠顶层,依次向下结束于树冠基部;展叶物候期共性表现在枝芽萌动期均在4月上旬,起始展叶期集中在4月中旬,展叶终期则在5月上旬到下旬;树龄较大的个体其枝芽萌动期、起始展叶期、展叶终期较树龄较小的个体早;其枝芽萌动期到展叶终期的时间进程较树龄较小的个体短;不同发育阶段的个体枝芽萌动期出现的时间较为离散,起始展叶期和展叶终期出现的时间较为集中。相关分析表明,出叶周期与枝条长度、枝条叶片数量和叶形指数呈极显著正相关,与叶面积和叶片干重呈显著负相关。     

The measurement of body segment inertial parameters using dual energy X-ray absorptiometry

Accurate body segment parameter (BSP) information is required for dynamic analyses of motion and the current methods available for obtaining these BSPs have been criticized. The purpose of this study was to determine whether dual energy X-ray absorptiometry (DXA) could accurately measure the BSPs of scanned objects and thus be used as a tool for measuring the BSPs of human subjects. Whole body mass (WBM) of 11 males was measured from a DXA scan and the values were compared to criterion scale-measured values by calculating the mean percent error. Two objects (plastic cylinder, human cadaver leg) were also scanned and DXA measurements of mass, length, centre of mass location (CM) and moment of inertia about the centre of mass (I_CM) were made using custom software. Criterion BSP measurements were then made and compared to DXA BSP values by calculating the percent error. Criterion I_CM measurements of the two objects were made using a pendulum technique and a second criterion I_CM calculation was made for the cylinder using a geometric formula. A mean percent error of −1.05% ±1.32% was found for WBM measurements of the human subjects. Errors for the cylinder and cadaver leg were under 3.2% for all BSPs except for I_CM when DXA was compared to the pendulum method (14.3% and 8.2% for cylinder and leg, respectively). The errors between DXA and the pendulum method were attributed to uncertainty in the pendulum technique (J. Biomech. 2002, in Review). I_CM error of the cylinder when DXA was compared to the geometric calculation was 2.63%. This error, combined with the low errors for all other BSPs, indicated that DXA can be used as a simple and accurate means of obtaining direct BSP information on living humans.     

Children's growth and body mass in the north,sub-Arctic and Arctic

There is very little data in world literature concerning the peculiarities of physical development of children in the high-latitude regions. In the meantime, such kinds of research is both of scientific and humanitarian interest. It is important to realize the specifics of growth of children living in the Arctic and sharp continental climate in view of the need to understand the biology of populations of extreme and sub-extreme regions. Such material would be of practical use for evaluation of fitness among children belonging to various ethnic groups of the north. The present paper is a sort of review of the data obtained by us in the course of research of growth and development of children in the northern regions of Russia undertaken since 1986. The whole bulk of material is too big and diverse to be presented in one single article. Part of the material is presented in the publication by A. Kozlov & G. Vershubsky (1999). Right now we shall talk only about age dynamics of body mass and mass-height index for children and teenagers from age 6 through 17.     

Trypsins and their role in carcinoma growth

There are more than 100 distinct types of cancer, and subtypes can be found within specific organs. Cancer progression is a complex multi-step process. These steps reflect alterations that drive the progressive transformation of normal cells into highly malignant ones. One critical step in tumor growth and invasion is the proteolytic processing of the extracellular matrix environment. The degradation of the extracellular matrix not only enables cell migration, invasion, and metastasis formation, but also affects cell behavior in multiple ways; on one hand by cleaving extracellular matrix bound growth factors and on the other hand by inhibiting angiogenesis into the tumor by liberating cryptic endogenous inhibitors of angiogenesis. Serine proteases and matrix metalloproteases are families of proteolytic enzymes involved in physiological and pathological extracellular matrix and basement membrane processing. In this review, we will focus on the role and activation of trypsinogens, a family of serine proteases, in cancer progression.     

LED光质及光周期对香子含笑幼苗生长和光合特性的影响

香子含笑(Michelia gioii)为我国珍贵阔叶树种,在用材、香料、景观等方面具有重要价值。为了进一步培育优良苗木和开发利用其非木质资源,该研究将香子含笑幼苗放置在由2个光周期(12、16 h·d^-1)和4种光质(R:B=8:1、R:B=6:1、R:B:P:G =8:1:1:1、R:B:P:G=6:1:1:1,其中R、B、P、G分别代表红光、蓝光、紫光、绿光)两两组合成、光照强度一致的8个光照条件下生长。结果表明:(1)香子含笑幼苗的苗高和地径增长量、叶长宽比、最大净光合速率、暗呼吸速率及光补偿点在12 h·d^-1光周期R:B=6:1光质下最高,叶面积和叶绿素含量在16 h·d^-1光周期R:B:P:G=6:1:1:1光质下最高。(2)16 h·d^-1光周期处理下的苗高增长量、叶面积、质量指数、叶绿素a+b含量、叶绿素a/b比值、类胡萝卜素含量和光饱和点均高于12 h·d^-1光周期。(3)在红蓝组合光质基础上添加紫、绿光提高了幼苗的质量指数,并影响光合色素的合成和积累;(4)光质R:B=6:1与R:B=8:1相比,更具有促进香子含笑幼苗苗高、地径、叶片生长及提高光合作用的潜力。综上结果认为,对于促进香子含笑幼苗生长和进行光合作用,光周期为 16 h·d^-1光质为R:B:P:G=6:1:1:1光照条件的潜力较大,其次是光周期为12 h·d^-1光质为R:B=6:1的光照条件。     

Analysing growth and development of plants jointly using developmental growth stages

Background and Aims Plant growth, the increase of organ dimensions over time, and development, the change in plant structure, are often studied as two separate processes. However, there is structural and functional evidence that these two processes are strongly related. The aim of this study was to investigate the co-ordination between growth and development using mango trees, which have well-defined developmental stages.Methods Developmental stages, determined in an expert way, and organ sizes, determined from objective measurements, were collected during the vegetative growth and flowering phases of two cultivars of mango, Mangifera indica. For a given cultivar and growth unit type (either vegetative or flowering), a multistage model based on absolute growth rate sequences deduced from the measurements was first built, and then growth stages deduced from the model were compared with developmental stages.Key Results Strong matches were obtained between growth stages and developmental stages, leading to a consistent definition of integrative developmental growth stages. The growth stages highlighted growth asynchronisms between two topologically connected organs, namely the vegetative axis and its leaves.Conclusions Integrative developmental growth stages emphasize that developmental stages are closely related to organ growth rates. The results are discussed in terms of the possible physiological processes underlying these stages, including plant hydraulics, biomechanics and carbohydrate partitioning.     

Heparin-binding growth factors and their receptors

Heparin-binding growth factors modulate diverse biological activities including cellular proliferation, cellular differentiation, morphogenesis, and angiogenesis. Biochemical characterization for two members of the heparin-binding growth factor family, acidic and basic fibroblast growth factors, is extensive, while characterization of the remaining five members is forthcoming. Cell surface receptors have been identified for acidic and basic fibroblast growth factors, but little is known concerning their sites of action in vivo or the mechanisms involved in transducing the energy of growth factor binding to a biological response. An understanding of the biological basis for the diversity of the heparin binding growth factor family and the in vivo actions of these factors will prove a major challenge to future research efforts.     

食物中多不饱和脂肪酸在家蝇幼虫体内的富集与代谢及对其生长的影响

【目的】阐明家蝇 Musca domestica 幼虫对食物中各种多不饱和脂肪酸的富集能力以及代谢转化情况,并探究各种多不饱和脂肪酸对家蝇幼虫生长的影响。【方法】在基础饲料中添加不同浓度(3%, 6%和12%)的多不饱和脂肪酸(亚油酸、α-亚麻酸、花生四烯酸和二十二碳六烯酸)饲养经过脱脂传代培养的家蝇幼虫;提取家蝇幼虫的总脂肪酸,利用气相色谱仪进行检测和分析;测定统计幼虫体重,以分析多不饱和脂肪酸对家蝇幼虫生长的影响。【结果】亚油酸、α-亚麻酸和花生四烯酸在家蝇幼虫体内均能被富集,且它们的富集程度随着食物中多不饱和脂肪酸的添加浓度的升高而增加,其中亚油酸、α-亚麻酸和花生四烯酸在幼虫体内富集的最高含量(占体内总脂肪酸的比例)分别为21.93%, 16.13%和9.68%,而二十二碳六烯酸不能在家蝇幼虫体内富集,提示家蝇幼虫食物中添加的各种多不饱和脂肪酸经过代谢后并没有在其体内产生新的脂肪酸,而食物中添加的二十二碳六烯酸在家蝇幼虫体内被分解代谢后消除。饲喂α-亚麻酸及花生四烯酸后家蝇幼虫体重增长较为明显,其中6%α-亚麻酸添加组的幼虫体重显著高于对照组(取食脱脂饲料)和3%和12%α-亚麻酸添加组,3%和6%花生四烯酸添加组的幼虫体重显著高于对照组和12%花生四烯酸添加组。【结论】家蝇幼虫体内能够从食物中富集部分多不饱和脂肪酸,多不饱和脂肪酸碳链越长其富集程度越低直至不能富集,富集的多不饱和脂肪酸对家蝇幼虫生长有不同程度的影响。     

The growth of whitefish in relation to water quality and fish species composition

Water quality in 16 Finnish lakes did not affect directly densely gill-rakered whitefish growth, except possibly in an acid (pH 4·9) lake, Iso Lehmaälampi, where acidity may have retarded the growth of whitefish. The density of roach affected whitefish growth in the second year of life: highest growth rates were in lakes without a roach population and lowest growth rates in lakes having strong roach populations. Competition by vendace also retarded the growth of young whitefish. The efficient mass removal of roach from a eutrophic lake was considered to have increased the growth rate of young whitefish. It is suggested that an examination of the fish species composition and relative abundance, as well as the growth of whitefish, can be used as an aid in predicting the success of stocking with whitefish.     

Plants in a crowded stand regulate their height growth so as to maintain similar heights to neighbours even when they have potential advantages in height growth

Background and Aims

Although being tall is advantageous in light competition, plant height growth is often similar among dominant plants in crowded stands (height convergence). Previous theoretical studies have suggested that plants should not overtop neighbours because greater allocation to supporting tissues is necessary in taller plants, which in turn lowers leaf mass fraction and thus carbon gain. However, this model assumes that a competitor has the same potential of height growth as their neighbours, which does not necessarily account for the fact that height convergence occurs even among individuals with various biomass.

Methods

Stands of individually potted plants of Chenopodium album were established, where target plants were lifted to overtop neighbours or lowered to be overtopped. Lifted plants were expected to keep overtopping because they intercept more light without increased allocation to stems, or to regulate their height to similar levels of neighbours, saving biomass allocation to the supporting organ. Lowered plants were expected to be suppressed due to the low light availability or to increase height growth so as to have similar height to the neighbours.

Key Results

Lifted plants reduced height growth in spite of the fact that they received higher irradiance than others. Lowered plants, on the other hand, increased the rate of stem elongation despite the reduced irradiance. Consequently, lifted and lowered plants converged to the same height. In contrast to the expectation, lifted plants did not increase allocation to leaf mass despite the decreased stem length. Rather, they allocated more biomass to roots, which might contribute to improvement of mechanical stability or water status. It is suggested that decreased leaf mass fraction is not the sole cost of overtopping neighbours. Wind blowing, which may enhance transpiration and drag force, might constrain growth of overtopping plants.

Conclusions

The results show that plants in crowded stands regulate their height growth to maintain similar height to neighbours even when they have potential advantages in height growth. This might contribute to avoidance of stresses caused by wind blowing.