Do oarsmen have asymmetries in the strength of their back and leg muscles?

The aim of this study was to establish whether asymmetry of the strength of the leg and trunk musculature is more prominent in rowers than in controls. Nineteen oarsmen and 20 male controls matched for age, height and body mass performed a series of isokinetic and isometric strength tests on an isokinetic dynamometer. These strength tests focused on the trunk and leg muscles. Comparisons of strength were made between and within groups for right and left symmetry patterns, hamstring: quadriceps ratios, and trunk flexor and extensor ratios. The results revealed no left and right asymmetries in either the knee extensor or flexor strength parameters (including both isometric and isokinetic measures). Knee extensor strength was significantly greater in the rowing population, but knee flexor strength was similar between the two groups. No difference was seen between the groups for the hamstring: quadriceps strength ratio. In the rowing population, stroke side had no influence on leg strength. No differences were observed in the isometric strength of the trunk flexors and extensors between groups, although EMG activity was significantly higher in the rowing population. Patterns of asymmetry of muscle activity were observed between the left and right erector spinae muscles during extension, which was significantly related to rowing side (P < 0.01). These observations could be related to the high incidence of low back pain in oarsmen.     

陕西南部大巴山区碘的分布规律与克汀病

通过对陕西南部大巴山地区的基岩、土壤、作物、泉水及地表水中含碘量和分布规律的研究,发现本区环境中碘的分布很不均衡,变化较大,包括从极低碘到高碘的多种情况.本区主要分布的早古生代地层均富碘,岩石的含碘量为 0.7～ 1.9mg/kg.在山坡坡度较缓的基性火成岩分布区的基岩、土壤、作物均富碘,一般为 1.4～ 0.9mg/kg.土壤的含碘量为 0.2～ 2.2mg/kg ;土豆的含碘量为 8～ 1 80 μg/kg.由于长期的风化剥蚀,大巴山区大多数地区的土壤和作物缺碘,特别是碳酸盐岩分布区以及高大山头上部的土壤和作物均缺碘.土壤和作物中含碘量与其分布区的基岩的岩性和含碘量以及地理环境密切相关,同时本区克汀病的分布和发病率与环境中碘的含量和分布也密切相关.     

实用针对性——成人教育的关键

本院地学教学部一直开设“普通地质学”课程,是为中国科学院系统所招研究生中非地质专业新生增设的基础课。然而,这门课也吸引了不少的旁听生。在笔者执教的8个学期内,总听课人数为138人,平均每学期17.25人。在研究生院各科目中属于中等人数。其中在校研究生总共91人,占66％(约2/3),旁听生47人,占34％(约1/3)。旁听生中除1人为中学教师外,46人全为地矿部系统在职人员,最多的是地矿部文献情报中心(以“全国地质图书馆——地质情报研究所”为主,还有全国地质资料局),其     

Is the occurrence of the sticking region the result of diminishing potentiation in bench press?

In this study we investigated if the occurrence of the sticking region was a result of diminishing potentiation (coinciding delayed muscle activation) or the result of a mechanically poor region in which the muscles can produce less force. A regular one-repetition maximum (1RM) free-weight bench press was compared with isometric bench presses performed at 12 different positions. A lower force at the sticking region compared to the other regions in the isometric bench presses would confirm the mechanically-poor-position hypothesis. Twelve resistance-trained males (age 21.7 ± 1.3 years, mass 78 ± 5.8 kg, height 1.81 ± 0.05 m) were tested in 1RM and in isometric contractions in bench press in 12 different positions, indicated by the vertical distance between barbell and sternum, covering the whole range of motion during the concentric phase. Barbell kinematics and muscle activity were registered. In both types of executions a region of lower force output was observed, which supports the mechanically-poor-position hypothesis. Electromyographic activity of four muscles showed the same pattern in the isometric and 1RM attempts. It was concluded that diminishing effect potentiation could not explain the existence of the sticking region.     

崇高风范亲切教导重读《再造中华辉煌——邓小平纪事》

崇高风范亲切教导重读《再造中华辉煌———邓小平纪事》●潘云唐在深情缅怀世纪伟人邓小平同志的日子里，重读中共党史出版社１９９４年出版的《再造中华辉煌———邓小平纪事》一书，感到分外亲切。这本书是由中共中央党史研究室倡仪、组织，在全国各省、自治区、直辖市...     

Assessing semantic-syntactic features of verbs from thirteen verb subsets

There are three major classes of verbs: intransitive, transitive, and linking. These three types of verbs can be divided into 13 semantic-syntactic subsets. Verbs within each subset give rise to sentences that have similar syntactic form, albeit a form distinct from that of sentences associated with other subsets. Preliminary research found that more than 90% of sentences written by children or for children contain verbs from 1 of the 13 verb subsets. The sentence form associated with each verb subset might be viewed as a "sentence template" that operationally defines a fixed set of 13 underlying semantic-syntactic relationships essential to communication. A strategy for assessing a child's knowledge of verbs from each subset is described.     

潜心研地质辛勤育英才--纪念地质教育家喻德渊先生百年华诞

原长春地质学院院长喻德渊先生是著名的地质学家和地质教育家,今年是他诞生一百周年.人们深情地缅怀他的光辉业绩和崇高风范.     

科学乎?迷信乎?

大约一年前在北京举行的科技普及与科教兴国研讨会上，科普大师们就科学普及和科学传播、反科学与反“科学主义”、科学与迷信，以及新闻的性质与功能等问题进行了认真研究和热烈讨论。大家对所谓“科学文化人”最近提出的若干“科普新见”给以有力的批判。     

科学家的强国梦——纪念钱三强院士百年诞辰

今年10月16日,是著名核物理学家钱三强院士百年诞辰,人们深情地缅怀这位伟大的科学家、社会活动家、青年教育家和"两弹一星"的元勋、功臣。钱三强出生在一个开明进步的书香世家,他父亲钱玄同曾任北京大学等高校教授,是"五四"时期"新文化运功"的主将,与陈独秀、李大钊、胡适、刘半农、沈尹默等创办了《新青年》杂志,他们6人轮流担任编辑。钱三强在这个充满文化气氛和爱国精神的家庭里受到很好的熏陶和教育,他刻苦学习,成绩优异,在那国难当头之际,他总是梦想着投身科学事业来救国,强国。他19岁那年,考入了清华大学物理系。系主任吴有训亲自指导他完成了毕业论文,结果很满意,毕业后又将他推荐到北平研究院物理研究所所长严济慈那里。他工作了几个月,表现很出色,又在严济慈的支持与鼓励下,考取了公费留学法国的资格。