一种有效的余弦调制滤波器组的设计方法

本文给出了一种有效的余弦调制滤波器组的设计方法。这种算法采用了内插法和迭代算法相结合设计原型滤波器,目标函数表示为滤波器系数的四次方,用迭代算法来优化滤波器的系数。这种方法使需要优化的参数大大减少。最后的实例仿真,验证了此算法的有效性。     

浅谈力学教学中提升学生的创新能力与素质

力学教学对当代大学生的创新能力和素质的培养有着重要的作用.该文结合教学实践和体会,通过力学史的渗透、多种教学手段相结合、“一题多解”的训练、使用力学知识解决生活实际问题和鼓励学生参加课程实践活动等方式,不断激发学生学习兴趣,提高思维积极性,培养创新精神,加强创新能力和科学素质.     

A qualitative analysis of context-aware ubiquitous learning environments using Bluetooth beacons

The use of Bluetooth Low Energy (BLE) beacons is becoming widespread for context-aware learning environments. This technology can be used in indoor and outdoor settings such as museums, shops, home and schools in order to identify the location of learners and their contexts. Specifically, in the constructivist view of learning, learners can use such sensing technology for constructing knowledge and experiencing learning at any time, anywhere. However, exploration of such technology has been limited in the constructivist context-aware ubiquitous learning (U-learning) literature. For this purpose, the authors evaluated two android-based U-learning applications: one was an outdoor learning environment in a garden, the other was about locating books in a library. The applications were implemented and tested with school and university students. The qualitative results are presented in this article, and show how such sensing technology is promising for both pedagogical environments.     

Optimization of cultural conditions for thermostable β-1, 3-1, 4-glucanase production byBacillus subtilis ZJF-1A5

The optimization of cultural conditions for β-glucanase production byBacillus subtilis ZJF-1A5 was investigated in flask trials. Temperature had great effect on β-glucanase production which maximized at optimal temperature of 37°C and decreased significantly when temperature was over 37°C. Charge quantity affected β-glucanase production significantly. Adding oxygen vector N-dodecane or acetic ether benefited β-glucanase production, but it depended on the concentration and charge quantity. The results of fractional factorial design showed that age and size of inoculum and shaking speed were the key factors affecting β-glucanase production and the cultivation time span to reach the highest β-glucanase activity. The optimal cultural conditions for β-glucanase production obtained with CCD were as follows: inoculum age and size (16 h, 3.82% (v/v)), shaking speed 210 r/min, charge quantity of 30 mL in 250 mL flask and initial pH 7.0, cultured at 37°C for 50 h. Repeated experimental results accorded with those predicted by a second-order polynomial model. The amount of β-glucanase, α-amylase and neutral protease produced byB subtilis ZJF-1A5 was associated partially with cell growth. Those three enzymes' activities increased following the cell growth and increased significantly when cells entered the stationary phase. Project (No. B0608) supported by the National Natural Science Foundation of China and a grant (2001121B25) from Hangzhou Science and Technology Development Project of Zhejiang Province, China     

Organizational culture,values, and routines in Iranian medical schools

In Iran, restructuring of medical education and the health care delivery system in 1985 resulted in a rapid shift from elite to mass education, ultimately leading to an increase in the number of medical schools, faculties, and programs and as well as some complications. This study aimed to investigate views on academic culture, values, and routines held by faculty members. A nation-wide survey conducted in six public medical schools in Iran. The research findings show weak organizational culture and values, together with routine behaviors sensed as a negative and low satisfaction with academic leadership. The research evidence suggests bureaucracy, politicization, conservativeness, and centralization as common features of medical schools in Iran and also suggests suitable supervisory skills to tackle the tension between governmental management and academic leadership with cultural changes, the creation of new values, and adoption more efficient routines.     

Allies in learning: critical insights into the importance of staff–student interactions in university education

Discussions of the quality of learning in university education often focus on curricula. Less attention is paid to the role of student–staff interactions. In a context in which a host of factors place pressure on the opportunities for students and staff to interact, it is important to use empirical insights to inform decisions about how to optimise learning. This paper uses data from a large survey of students and teaching staff in Australia to suggest that students and staff should be regarded as allies in learning. It investigates student reports to suggest that frequent interactions with those who teach them lead to higher levels of student engagement and satisfaction and lower attrition rates. The advantages do not only flow in one direction. Teaching staff gain insights into students' learning experiences, providing them with clues to better target their teaching.     

Hypoglycemic, hypolipidemic and antioxidant properties of combination ofCurcumin fromCurcuma longa, Linn, and partially purified product fromAbroma augusta, Linn. in streptozotocin induced diabetes

Dietary spice components ofCurcuma longa andAbroma augusta have been screened for their protective effect against reactive oxygen species induced lipid peroxidation. They have been found to be efficient antioxidant when administered in combination. The purpose of the study was to investigate the effect of oral administration (300mg/Kg) of the aqueous extract of turmeric whose active ingredient isCurcumin andAbromine powder as a hypoglycemic agent mixed with diet. The effect of this aqueous extract on blood glucose, lipid peroxidation (LPO) and the antioxidant defense system in rat tissues like liver, lung, kidney and brain was studied for 8 weeks in streptozotocin induced diabetic rats. The administration of an aqueous extract of turmeric and abromine powder resulted in a significant reduction in blood glucose and an increase in total haemoglobin. The aqueous extract also resulted in decreased free radical formation in the tissues studied. The decrease in thiobarbituric acid reactive substances (TBARS) and increase in reduced glutathione (GSH), superoxide dismutase (SOD) and catalase (CAT) clearly showed the antioxidant property of the mixture. It is suggested that these changes initially counteract the oxidative stress in diabetes however, a gradual decrease in the antioxidative process may be one of the factors which results in chronic diabetes. These results indicate that the mixture of the two plants have shown antidiabetic activity and also reduced oxidative stress in diabetes. A combination ofAbroma augusta and Curcuma longa also restored the other general parameters in diabetic animals. The results were statistically analyzed and indicated that combination of herbal extracts showed better efficacy as compared to individual herbal plant extracts used.     

Neural embedding-based indices for semantic search

Traditional information retrieval techniques that primarily rely on keyword-based linking of the query and document spaces face challenges such as the vocabulary mismatch problem where relevant documents to a given query might not be retrieved simply due to the use of different terminology for describing the same concepts. As such, semantic search techniques aim to address such limitations of keyword-based retrieval models by incorporating semantic information from standard knowledge bases such as Freebase and DBpedia. The literature has already shown that while the sole consideration of semantic information might not lead to improved retrieval performance over keyword-based search, their consideration enables the retrieval of a set of relevant documents that cannot be retrieved by keyword-based methods. As such, building indices that store and provide access to semantic information during the retrieval process is important. While the process for building and querying keyword-based indices is quite well understood, the incorporation of semantic information within search indices is still an open challenge. Existing work have proposed to build one unified index encompassing both textual and semantic information or to build separate yet integrated indices for each information type but they face limitations such as increased query process time. In this paper, we propose to use neural embeddings-based representations of term, semantic entity, semantic type and documents within the same embedding space to facilitate the development of a unified search index that would consist of these four information types. We perform experiments on standard and widely used document collections including Clueweb09-B and Robust04 to evaluate our proposed indexing strategy from both effectiveness and efficiency perspectives. Based on our experiments, we find that when neural embeddings are used to build inverted indices; hence relaxing the requirement to explicitly observe the posting list key in the indexed document: (a) retrieval efficiency will increase compared to a standard inverted index, hence reduces the index size and query processing time, and (b) while retrieval efficiency, which is the main objective of an efficient indexing mechanism improves using our proposed method, retrieval effectiveness also retains competitive performance compared to the baseline in terms of retrieving a reasonable number of relevant documents from the indexed corpus.     

A Cross-Age Study of the Understanding of Three Genetic Concepts: How Do They Image the Gene, DNA and Chromosome?

The study was carried out with 175 Turkish students by using drawings at different ages understanding of gene, DNA and chromosome concepts. Students from 8th, 9th, 11th grades and, science and biology student teachers were simply asked to draw the structure of gene, DNA and chromosome in a cell and also to give explanations about these three concepts. Differences in understanding between the age groups were found to be significant for the concepts of gene and DNA. None of the groups exhibit sound understanding and regardless of the age levels, students in all groups had alternative ideas about the three concepts investigated.