电-机械延迟的研究现状和趋势

参考国内外的相关文献,阐述电-机械延迟与肌纤维类型、运动疲劳、年龄性别、遗传及环境、肌肉本身状态等关系的研究现状和未来研究趋势.探讨把电—机械延迟运用到实践中,评定运动能力和作为早期运动选材的可靠指标.     

建构主义教学方法在遗传育种教学中的应用

建构主义对发展现代学习技术具有重要的影响,将建构主义应用于遗传育种教学,适合学生终生学习的要求,在遗传育种教学改革中很有意义。在遗传育种教学中运用建构主义的教学方法,主要可以采用其中较为成熟的“支架式”教学法、“抛锚式”教学法和“随机引入”教学法等三种。     

Longitudinal Genetic Analysis of Early Reading: The Western Reserve Reading Project

We examined the genetic and environmental contribution to the stability and instability of reading outcomes in early elementary school using a sample of 283 twin pairs drawn from the Western Reserve Reading Project. Twins were assessed across two measurement occasions. In Wave 1, children were either in kindergarten or first grade. Wave 2 assessments were conducted one year later. Results suggested substantial genetic stability across measurement occasions. Additionally, shared environmental influences also accounted for stability, particularly for variables more closely tied to direct instruction such as phonological awareness, letter knowledge, and word knowledge. There was also evidence for independent genetic and shared environmental effects, suggesting that new sources of variance may emerge as the demands of school change and children begin to acquire early reading skills.     

Identifying sex differences in reading disability

The issue of sex differences in reading disability has been of recent interest in relation to sex ratios in families with reading disabled children and to possible sex biases in referred populations. Data from a study of 570 twins are used to develop alternative definitions of reading disability that vary in the manner to which sex effects are taken into account. These definitions include discrepancies between reading quotients and IQ, the use of the regression of reading onto IQ and chronological age/reading age differences. In each case the reading and spelling disability was defined either separately for the sexes or based upon the data for the sexes combined and with and without an IQ>90 exclusion criterion. The consequences of using the alternative definitions for prevalence, sex ratio and heritability are examined. The results demonstrate that the characteristics of reading disabled children vary with the way disability is defined. The excess of males seems to be a robust finding. Definitions that take into account differences in mean score for males and females reduce but do not eradicate the sex ratio. From the genetic analysis, there is no support for the suggestion that the genetic effect on reading is greater for females than males. It is concluded that the use of regression based procedures for identifying reading disability is desirable but that at present there is insufficient evidence to justify the adoption of separate regression procedures for the two sexes.     

浅谈遗传学教学中学生阅读能力的培养

生物阅读是一种主动式的阅读,要求在适当的地方,手脑结合,通过思维或推演主动预测或概括下文将要给出的结论．在遗传学教学中对学生阅读能力的培养的着力点可以放在研读课文、研读信息题等方面．     

Association of CETP and LIPC Gene Polymorphisms with HDL and LDL Sub-fraction Levels in a Group of Indian Subjects: A Cross-Sectional Study

There is an increasing interest to understand the molecular basis of high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) subfractions and their association with coronary artery disease (CAD). The formation of these subfractions is greatly influenced by hepatic lipase (HL) and cholesteryl ester transfer protein (CETP) enzymes. To identify genetic markers influencing LDL and HDL subfractions and their role in CAD we performed a case–control genetic association study on 117 healthy controls and 119 angiographically verified CAD patients. Biochemical analysis was performed using standard assays. HDL-C and LDL-C subfractions were estimated using precipitation methods. Genotyping of C-514T (rs1800588) in the LIPC gene for HL and I405V (rs5882) in the CETP gene was done using PCR-based restriction enzyme analysis and sequencing. Both the polymorphisms were not associated with CAD. The C-514T was associated with increased HDL₃-C levels in controls (P = 0.049). The I405V polymorphism was found to be associated with low levels of small dense, LDL (P = 0.038). A multiple regression analysis showed that the effects were dependent on gender and triglyceride levels. We conclude that these polymorphisms are not associated with CAD but are important determinants of HDL-C and small dense LDL particles in our population.     

Expertise for Teaching Biology Situated in the Context of Genetic Testing

Contemporary genomics research will impact the daily practice of biology teachers who want to teach up-to-date genetics in secondary education. This article reports on a research project aimed at enhancing biology teachers’ expertise for teaching genetics situated in the context of genetic testing. The increasing body of scientific knowledge concerning genetic testing and the related consequences for decision-making indicate the societal relevance of an educational approach based on situated learning. What expertise do biology teachers need for teaching genetics in the personal health context of genetic testing? This article describes the required expertise by exploring the educational practice. Nine experienced teachers were interviewed about the pedagogical content, moral and interpersonal expertise areas concerning how to teach genetics in the personal health context of genetic testing, and the lessons of five of them were observed. The findings showed that the required teacher expertise encompasses specific pedagogical content expertise, interpersonal expertise and a preference for teacher roles and teaching approaches for the moral aspects of teaching in this context. A need for further development of teaching and learning activities for (reflection on) moral reasoning came to the fore. Suggestions regarding how to apply this expertise into context-based genetics education are discussed.     

Evaluating Secondary Students’ Scientific Reasoning in Genetics Using a Two‐Tier Diagnostic Instrument

While genetics has remained as one key topic in school science, it continues to be conceptually and linguistically difficult for students with the concomitant debates as to what should be taught in the age of biotechnology. This article documents the development and implementation of a two‐tier multiple‐choice instrument for diagnosing grades 10 and 12 students’ understanding of genetics in terms of reasoning. The pretest and posttest forms of the diagnostic instrument were used alongside other methods in evaluating students’ understanding of genetics in a case‐based qualitative study on teaching and learning with multiple representations in three Western Australian secondary schools. Previous studies have shown that a two‐tier diagnostic instrument is useful in probing students’ understanding or misunderstanding of scientific concepts and ideas. The diagnostic instrument in this study was designed and then progressively refined, improved, and implemented to evaluate student understanding of genetics in three case schools. The final version of the instrument had Cronbach’s alpha reliability of 0.75 and 0.64, respectively, for its pretest and the posttest forms when it was administered to a group of grade 12 students (n = 17). This two‐tier diagnostic instrument complemented other qualitative data collection methods in this research in generating a more holistic picture of student conceptual learning of genetics in terms of scientific reasoning. Implications of the findings of this study using the diagnostic instrument are discussed.     

The Comparative Effects of Prediction/Discussion‐Based Learning Cycle,Conceptual Change Text,and Traditional Instructions on Student Understanding of Genetics

The present study examined the comparative effects of a prediction/discussion‐based learning cycle, conceptual change text (CCT), and traditional instructions on students' understanding of genetics concepts. A quasi‐experimental research design of the pre‐test–post‐test non‐equivalent control group was adopted. The three intact classes, taught by the same science teacher, were randomly assigned as prediction/discussion‐based learning cycle class (N = 30), CCT class (N = 25), and traditional class (N = 26). Participants completed the genetics concept test as pre‐test, post‐test, and delayed post‐test to examine the effects of instructional strategies on their genetics understanding and retention. While the dependent variable of this study was students' understanding of genetics, the independent variables were time (Time 1, Time 2, and Time 3) and mode of instruction. The mixed between‐within subjects analysis of variance revealed that students in both prediction/discussion‐based learning cycle and CCT groups understood the genetics concepts and retained their knowledge significantly better than students in the traditional instruction group.