Using deductive reasoning to promote the change of students' conceptions about force and motion

Deductive reasoning is a basic logic form used in scientific explanations and predictions. In dynamics, the process of finding the direction of force acting on a moving object, from the change of its motion, can be structured as a syllogism that is an elementary model of deduction. In this study, the syllogistic form of a scientific explanation task was used to help middle school students change their prior conceptions about force and motion. However, because the conclusion drawn from a syllogistic explanation task contradicted students' prior ideas, many rejected the conclusion or reached another conclusion without using deductive reasoning. From the preliminary interview using the syllogistic explanation task with eight students, we found four factors preventing students' use of deductive reasoning. In the main interview designed to remove these obstacles, it was observed that 26 of the 27 students could find the direction of force correctly by using deduction. Finally, implications for classroom teaching are     

Book Review Section 2

A persistent belief in American culture is that males both outperform and have a higher inherent aptitude for mathematics than females. Using data from two school districts in two different states in the United States, this study used longitudinal multilevel modeling to examine whether overall performance on standardized as well as classroom tests reveals a gender difference in mathematics performance. The results suggest that both male and female students demonstrated the same growth trend in mathematics performance (as measured by standardized test scores) over time, but females' mathematics grade-point average is significantly higher than males. These results are discussed in the context of present day standardized assessment in the United States that may motivate teachers to focus on higher expectations for mathematics performance regardless of gender, thus challenging cultural beliefs that stigmatize mathematics as masculine in the United States.     

韩国大学教育的近况和展望

20世纪90年代以来,韩国大学数量快速上升,但是这种数量的上升并不意味着教育质量的上升,同时还面临一些问题,例如随着出生率的降低大学生的数量也逐渐减少,国际化现象所带来的教育市场的变化,信息化社会所带来的多种教育形态的出现,经济的影响,以及对大学的相关社会性认识的变化等,韩国社会一直要求寻找解决的办法,韩国大学今后应该恰当解决这些问题,同时谋求教育质量的提高。     

Greenhouse gas emission reduction in public buildings according to greenhouse gas reduction policies in Daegu

The issues related to climate change such as depletion of energy resources and continuous high oil prices,global warming,and development of clean energy are adopted and discussed as a national agenda i...     

Electricity consumption propensity of different household members in apartment house

South Korea is an energy-guzzling country.Economic reasons in the country force its households to save more energy.Household energy consumption in South Korea has grown slow compared to other sectors a...     

C60原子团簇电子结构的半经验研究 ——分子动力学与MNDO近似

用经典分子动力学以及量子化学的一种自洽求解数值方法 MNDO(m odified neglect of diatom ic overlap)研究了C6 0 原子团簇电子结构 .同时考虑σ-轨道和π-轨道 ,计算了一个电子能量级、对称性、π-轨道包含率、电子激发能量、凝聚能量、离子化能量以及电子亲和力 .得到的分子轨道比率显示了 σ-轨道和 π-轨道之间的明显分离 ,π-轨道大部分存在于HOMO-和 L U MO-能量级附近 .计算结果与对应的实验数值相当一致     

Agrobacterium-mediated transformation of herbicide resistance in creeping bentgrass and colonial bentgrass

Embryogenic calli were induced from the seeds of creeping bentgrass (Agrostis palustris Huds.) cv. Regent and colonial bentgrass (Agrostis Tenuis Sibth. Fl. Oxen.) cv. Tiger. The embryogenic calli were precultured on fresh medium for 4-7 days and then co-cultivated with Agrobacterium tumefaciens, LBA4404, which contains plasmid vector-pSBGM harboring bar coding region, synthetic green fluorescent protein (sGFP) coding region and matrix attachment region (MAR). After 3 days of co-cultivation, the calli were washed thoroughly and transferred to MS medium containing 2 mg/L of 2, 4-D, 12-15 mg/L phosphinothricin (PPT) and 250 mg/L of cefotaxime. After 2-3 months of selection, the actively growing calli of 'Regent' and 'Tiger' were transferred to MS medium with 12-15 mg/L PPT and 250 mg/L cefotaxime for regeneration. The putative transformants were maintained on MS medium with 3 mg/L PPT for long period but control died within 1 month. After establishing in greenhouse, the transformants also showed strong resistance to 0.4% of herbicide Basta but control plants died within 2 weeks. Under confocal microscope, both young leaves and roots showed significant GFP expression. PCR analysis revealed the presence of a DNA fragment of GFP gene at the expected size (380 bp) in the transformants and its absence in a randomly selected control plant.