对土家族城镇中小学生体表面积调查研究

为了解和建立土家族中小学生这方面的形态学指标,采用适合中国人的Stevenson标准公式,对土家族中小学生的体表面积进行了调查研究.结果显示:1)土家族中小学生体表面积值随着年龄增长而增长,且其增长速度男女生均可分为匀速增长期、快速增长期、速度减缓期3个不同时期;2)男女生体表面积曲线出现双交叉现象,即11岁时女生体表面积值超过男生,14岁时男生的体表面积又超过女生,15岁以后二者体表面积值的差异逐渐增大,表现出显著性差异.     

我国备战与征战奥运会中有待思考与解决的问题

为有助于我国奥运选手在未来奥运会上取得理想运动成绩,采用文献研究和逻辑分析等方法对我国备战与征战奥运会过程中有待思考与解决的3个问题:国家队教练组组构与功能、运动竞赛中“黑马现象”与“黑马心理”以及经验训练与科学训练等进行了初步探讨。研究认为,国家队教练组应是一个由多学科专家组成的高素质团队;比赛中出现的“黑马”主要源于其“心理”;现阶段,经验训练对金牌贡献率大于所谓的“科学训练”。     

基于点云数据的复杂型面实体建模研究

文章针对复杂型面产品的特点,从工业产品设计的实际应用出发,提出将正向设计的尺寸和定位关系设计方法和逆向设计的复杂曲面设计方法有效结合起来,基于点云数据实现产品的实体模型重建。以摩托车覆盖件为例,利用逆向工程软件从点云数据中提取和重构特征曲线与曲面,然后将这些几何元素信息在正向设计系统中结合特征建模方法创建整体三维CAD模型。     

大世界悖理与小世界现象——情报交流研究新进展

简述了大世界悖理与小世界现象的涵义及其实验研究和基本内容，指出了它们对情报学和网络交流的影响。     

信息经济学与图书馆发展战略

信息经济学对图书馆学的影响和渗透，促进了图书馆学的发展，扩大了其研究对象，深化了其研究内容。这对于认识图书馆学“公益性”和“经济性”的不同见解是有启示的。     

Development of a chemically defined medium for Planctopirus limnophila to increase biomass production

BackgroundPlanctomycetes is a phylum of biofilm-forming bacteria with numerous biosynthetic gene clusters, offering a promising source of new bioactive secondary metabolites. However, the current generation of chemically defined media achieves only low biomass yields, hindering research on these species. We therefore developed a chemically defined medium for the model organism Planctopirus limnophila to increase biomass production.ResultsWe found that P. limnophila grows best with a 10 mM sodium phosphate buffer. The replacement of complex nitrogen sources with defined amino acid solutions did not inhibit growth. Screening for vitamin requirements revealed that only cyanocobalamin (B12) is needed for growth. We used response surface methodology to optimize the medium, resulting in concentrations of 10 g/L glucose, 34 mL/L Hutner’s basal salts, 23.18 mM KNO₃, 2.318 mM NH₄Cl and 0.02 mg/L cyanocobalamin. The analysis of amino acid consumption allowed us to develop a customized amino acid solution lacking six of the amino acids present in Aminoplasmal 10%. Fed-batch cultivation in a bioreactor using the optimized medium achieved a final ΔOD₆₀₀ of 46.8 ± 0.5 after 108 h, corresponding to a cell dry weight of 13.6 ± 0.7 g/L.ConclusionsThe optimized chemically defined medium allowed us to produce larger amounts of biomass more quickly than reported in earlier studies. Further research should focus on triggering P. limnophila biofilm formation to activate the gene clusters responsible for secondary metabolism.How to cite: Kruppa OC, Gerlach D, Fan R, et al. Development of a chemically defined medium for Planctopirus limnophila to increase biomass production. Electron J Biotechnol 2021;54. https://doi.org/10.1016/j.ejbt.2021.09.002.     

教师职业研究的新视角——情绪工作研究探析

首先从情绪工作的定义、特征出发分析教师是属于高情绪工作者,之后阐述情绪工作的调节策略以及影响调节策略的相关因素,以期为研究教师职业提供一个新视角。     

流行美剧的粉文化传播模式研究——以“谢耳朵”现象为例

通过"谢耳朵T恤现象",聚焦流行美剧粉丝在自我身份认知过程中缔造的文化传播模式。经过比较与分析,认为流行美剧的粉文化传播,既脱离不了现实基础,也需要多方合力的促进。     

Exploring Developmental Appropriateness of Multitouch Tables in Prekindergarten: A Video Analysis

This study explored how developmentally appropriate practices influenced the affordances of a multitouch surface in an early childhood classroom. Children, ages 4 to 5 years old, were videotaped while engaged in a storymaking application on a multitouch table. As a result of the study, we found that some challenges with the functionality undermined children's autonomous control. The researchers observed numerous instances of issues with control of the medium, including height of the table, sensitivity to multiple types of touch, and limited instructions and prompts. Implications for future research and practice are discussed.     

A kinematic analysis of the spine during rugby scrummaging on natural and synthetic turfs

Artificial surfaces are now an established alternative to grass (natural) surfaces in rugby union. Little is known, however, about their potential to reduce injury. This study characterises the spinal kinematics of rugby union hookers during scrummaging on third-generation synthetic (3G) and natural pitches. The spine was sectioned into five segments, with inertial sensors providing three-dimensional kinematic data sampled at 40 Hz/sensor. Twenty-two adult, male community club and university-level hookers were recruited. An equal number were analysed whilst scrummaging on natural or synthetic turf. Players scrummaging on synthetic turf demonstrated less angular velocity in the lower thoracic spine for right and left lateral bending and right rotation. The general reduction in the range of motion and velocities, extrapolated over a prolonged playing career, may mean that the synthetic turf could result in fewer degenerative injuries. It should be noted, however, that this conclusion considers only the scrummaging scenario.