布格缪勒钢琴练习曲op.109创作特征及教学意义

布格缪勒钢琴练习曲Op.109具有标题性、音乐性、技术性和性格多样性四个方面的创作特征。作品有助于培养学生对音乐的理解力和想象力,提高学生对弹奏练习曲的兴趣,同时也有利于增强学生对不同性格音乐的驾驭能力。     

Effects of zinc on cadmium uptake by spring wheat （Triticum aestivum, L.）： long-time hydroponic study and short-time ^109Cd tracing study

To investigate effects of Zn on Cd uptake by spring wheat (Triticum aestivum, L.) in solution culture, long-time hydroponic experiment (1 month) (Experiment 1) and short-time Cd isotope (109Cd) tracing experiment (24 h) (Experiment 2) were conducted. In Experiment 1, spring wheat (cv. Brookton) was grown in nutrient solution at uniform cadmium concentration of 20μ mol/L and 10 zinc concentrations (0, 1, 5, 10, 20, 100, 200, 500, 1000, 2000 μ mol/L). In Experiment 2, spring wheat seedlings,pre-cultivated in complete nutrient solution, were treated with 109Cd of uniform activity and the same series of Zn concentrations as those in Experiment 1 for 24 h. Cd concentrations in shoots and roots in Experiment 1 increased marginally but not consistently with Zn increasing at Zn rates of 1～200 μmol/L, and then decreased significantly at high rates (＞200 μ mol/L). In Experiment 2, the response of 109Cd activities in shoots and roots to increasing Zn was greatly similar to the response of Cd concentrations to Zn increasing in Experiment 1. The results of the two experiments indicated that the short-time and long-time exposure of spring wheat to Zn had similar effects on Cd accumulation.     

A small study assessing teacher effectiveness: Does learning last?

Students of six classes who had previously participated in a larger study of teaching styles were tested a year after completion of the course. The purpose of the follow-up was to determine whether or not the prior battery of tests, including a student evaluation of instructor form, the Introductory Psychology Criteria Test, an Attitude Toward Psychology Scale, and a knowledge test, administered in a large group setting independent of those used for grades by instructors, would be positively related to student performance on comparable tests given a year later. The follow-up measures included items from the above measures plus questions regarding experiences and readings related to psychology in the year since the students' introductory course and two brief experiments which the students were to critique. Results indicated that the end of the semester measures of teaching effectiveness in terms of student performance and attitudes were positively related to similar responses obtained a year later.