例谈高中地理研学调查活动的开展——以调查银川贺兰山东麓葡萄栽植、葡萄酒产销情况为例

依据课程标准策划地理研学调查活动,有助于培养高中生的地理实践力素养。高中地理教师应注重整合校内外的学科资源,组织研学调查活动等,引导学生发扬自身优点,改掉缺点,最终促进学生的长足进步和长远发展。

探讨高职学生厌学形成——以高职院校41例学生为例

21世纪以来,国家大力发展职业教育,《国家职业教育改革实施方案》指出职业教育与普通教育是两种不同教育类型,具有同等重要地位。但在我国职业教育发展的黄金时期下,高职学生厌学现象较为普遍,且呈现不断上升的趋势。高职生厌学问题越来越受到学术界的关注,厌学问题已成为困扰职业院校的主要问题之一。本研究选取高职院校41例厌学学生,进行详细访谈,获取一手资料,深度剖析高职院校学校厌学现状。

Adaptive changes of gastro-entero-pancreatic system endocrine cells in the black-spotted pond frog Rana nigromaculata after fasting

Changes in distribution density,morphology and secretory content of endocrine cells in the gastro-entero-pancreatic system of black-spotted frogs Rana nigromaculata before and after fasting were investigated using immunohistochemistry and antisera to six gut hormones.Six types of endocrine cells were detected in the digestive tract of Rana nigromaculata,including 5-hydroxytryptamine(5-HT),gastrin(GAS),somatostatin(SOM),glucagon(GLU),pancreatic polypeptide(PP)and vasoactive intestinal polypeptide(VIP)cells.After fasting,the density of 5-HT cells in the esophagus,cardia and fundus,GAS cells in the fundus and pylorus,PP cells in the fundus decreased significantly(P<0.01),while SOM cells in the cardia,GLU cells in the rectum increased significantly(P<0.01).The cytoplasmic processes of 5-HT cells became shorter or not detectable.The secretory content of GAS cells reduced in the cardia.The positive immunostaining reaction in the perinuclear region of SOM cells in the cardia,fundus and pylorus became weaker,while the staining intensity in the periphery of these cells became stronger.VIP cells were not detectable in the whole digestive tract after fasting.Five types of endocrine cells were found in the pancreas of Rana nigromaculata,including 5-HT,GAS,SOM,GLU and PP cells.After fasting,the density of 5-HT cells decreased slightly(P>0.05),while SOM,GAS,GLU and PP cells increased significantly(P<0.01).Furthermore,the secretory content of GLU cells increased significantly.Considering their functionalities,our results indicate that the changes of GEP endocrine cells in Rana nigromaculata responded adaptively to starvation-induced stress.

Melatonin and schistosomal antigens ameliorate the anti-oxidative and biochemical response to Schistosoma mansoni infection in hamster

The present study was designed to investigate the potential protective effect of melatonin as an antioxidant separately or in combination with antigens （cerearial; CAP or soluble worm; SWAP） against Schistosoma mansoni infection in hamsters. Each hamster was sensitized with an initial immunization of 0.6 ml of the extracted antigen （30μg protein/mL）. After four days, a second injection of 0.4 mL was given （20μg protein/mL）. Then, each hamster was exposed to 260 ± 20 S. mansoni cercariae followed with melatonin treatment （3.5 mg/kg） for thirty days from the 1st day of post infection. Levels of lipid peroxidation （LPO） products, eatalase （CAT） activity, hepatic glutathione （GSH） and biochemical changes in the liver and kidneys functions were investigated. The results revealed a high significant increasing of LPO and decreasing of CAT and GSH in liver of infected hamsters. Biochemical observations showed severe damage in the liver enzyme activities and increasing cholesterol level in infected animals. Melatonin co-treatment with antigen to the infeeted-hamster attenuated the increase of LPO and restored the activity of CAT and levels of hepatic GSH. Also, the biochemical damages in the liver and kidneys funetions were reduced. The present study suggests that melatonin may be useful in combating free radical-induced damage due to infection toxicity. The immunization with previous antigens resulted in a remarkable improvement on the liver enzyme activities, which were increased after infection. Thus, vaccination of hamsters with antigens （both CAP and SWAP） and melatonin treatment has more potent effect on the enhancement of antioxidant and biochemical of S. mansoni infected-hamster than each treatment separately. Immunization of the hamster with SWAP followed by melatonin was the best way among the other regime treatments to improve the biochemical and antioxidant parameters of the infected-hamsters.

How to Teach Academic Reading More Effectively： Reading-Aloud Approach

In furtherance of their most recent research on the textbook of the course LC （language and communication） 4001 Reading Skills Development in English for Graduate Studies （2012）, the co-authors carried out a follow-up work on read-aloud approach as some students voiced a sense of dissatisfaction with regard to such means which was primarily used in the LC 4001 class taking place from August 8 to November 27, 2012. In the current study, the data were garnered from 37 students enrolling in LC 4001 from January 8 to May 7, 2013. Based on the questionnaire, the findings revealed that a large number of the English reading learners acknowledged the mounting importance of English as a linguafranca in the region of 84% and 16% at the ＂most＂ and ＂much＂ levels, respectively. Likewise, around 90% of the participants had a positive attitude toward such pedagogical method, while only 10% disliked it. Concerning the academic reading curriculum for higher English reading competence, students＇ different language learning backgrounds and personal excitement caused by reading-aloud activities should be taken on board. Any activity introduced into the classroom should be explicitly stated to the students at the beginning of the course. Using any instructional approach without clear explanations or precautions may seriously upset learners partially or even completely obstruct their effective learning

Teaching Programming Concepts to K-12 Teachers With Scratch

This study aims to investigate teaching programming concepts to K-12 teachers with Scratch. A total of 10 K-12 teachers enrolled in one graduate course participated in this study. They received lectures, took practices and exercises of Scratch programming and were then asked to design and implement their projects before the semester. It was found that teaching programming concepts to K-12 teachers with Scratch is feasible. K-12 teachers with less computer background can learned basic programming concepts and applied them in their project code implementation. Although no significant difference was found between participants＇ pre-test and post-test on programming self-efficacy, positive attitudes toward learning Scratch programming was revealed in the questionnaire survey and results of interviews. This study paves a way for referring to the teaching of programming concepts for K- 12 teachers.

Motivation in a Flipped Classroom, a Case Study of Teaching Oral English in a Vocational College in China's Mainland

This action research explores the use of the flipped classroom approach in an English speaking class with 25 students at intermediate level in a vocational college in China's Mainland. It aims at motivating English learners and helping them develop communicative language skills more effectively and efficiently. Both qualitative and quantitative methods are adopted to analyze the data collected through interviews, teaching logs, as well as anonymous questionnaires and a summative assessment. Results show that the flipped classroom approach does stimulate students to invest more time and effort prior to instruction and during class learners do participate in communicative language exercises more enthusiastically. As a result, conceivable progress has been made in learners＇ performance. Possible recommendations of incorporating periodic rotation within the class, adding certain teacher-led instruction, and informal evaluation with group members, are raised at the end of the paper to help further improve the teaching/learning outcome of the flipped classroom approach.

基于小波消噪的EMD模型在GPS振动信号处理中的应用

经验模式分解和小波分解是当前有效处理非平稳信号的两种时频分析方法,它们各具有其优缺点,适用于不同的应用。从对GPS振动信号的预处理、时域和频域处理入手,结果分析表明,对GPS振动信号先进行小波滤波消除随机噪声的干扰,再应用经验模式分解更有利于变形特征信息的分离和提取,提取的信号与振动平台记录数据更加吻合。

Numerical Simulation on the Effect of Tip Clearance Size on Unsteadiness in Tip Clearance Flow

Unsteadiness of tip clearance flow with three different tip clearance sizes is numerically investigated in this paper. NASA Rotor 67 is chosen as the computational model. It is found that among all the simulated cases, the un- steadiness exists when the size of the tip clearance is equal to or larger than design tip clearance size. The relative total pressure coefficient contours indicate that region of influence by tip leakage flow augments with the increase of tip clearance size at a fixed mass flow rate. Root Mean Square contours of static pressure distribution in the rotor tip region are provided to illustrate that for design tip clearance （1.1% tip chord） the strongest fluctuating region is located on pressure side of blade near leading edge, while for the larger tip clearance （2.2% tip chord）, it is in the region of the interaction between the shock wave and the tip leakage flow.

Effects of Axial Non-uniform Tip Clearances on Aerodynamic Performance of a Transonic Axial Compressor

This paper presents a numerical investigation of effects of axial non-uniform tip clearances on the aerodynamic performance of a transonic axial compressor rotor （NASA Rotor 37）. The three-dimensional steady flow field within the rotor passage was simulated with the datum tip clearance of 0.356 mm at the design wheel speed of 17188.7 rpm. The simulation results are well consistent with the measurement results, which verified the numeri- cal method. Then the three-dimensional steady flow field within the rotor passage was simulated respectively with different axial non-uniform tip clearances. The calculation results showed that optimal axial non-uniform tip clearances could improve the compressor performance, while the efficiency and the pressure ratio of the com- pressor were increased. The flow mechanism is that the axial non-uniform tip clearance can weaken the tip leak- age vortex, blow down low-energy fluids in boundary layers and reduce both flow blockage and tip loss.