Scaling behavior of nucleotide cluster in DNA sequences

In this paper we study the scaling behavior of nucleotide cluster in 11 chromosomes of Encephalitozoon cuniculi Genome. The statistical distribution of nucleotide clusters for 11 chromosomes is characterized by the scaling behavior of P（S） ∝ e^-αs＇ where S represents nucleotide cluster size. The cluster-size distribution P（S1＋S2） with the total size of sequential C-G cluster and A-T cluster S1＋S2 were also studied. P（S1＋S2） follows exponential decay. There does not exist the case of large C-G cluster following large A-T cluster or large A-T cluster following large C-G cluster. We also discuss the relatively random walk length function L（n） and the local compositional complexity of nucleotide sequences based on a new model. These investigations may provide some insight into nucleotide cluster of DNA sequence.     

Novel high torque bearingless two-sided rotary ultrasonic motor

Applications are limited at present because the currently available ultrasonic motors (USMs) do not provide suffi-ciently high torque and power. The conventional travelling-wave USM needs the bearing to support, which required lubricant. To solve the above problem, a bearingless travelling-wave USM is designed. First, a novel structure of the two-sided USM consisting of a two-sided teeth stator and two disk-type rotors is designed. And the excitation principle of the two-sided travelling-wave USM is analyzed. Then, using ANSYS software, we set up the model of the stator to predict the excitation frequency and modal response of the stator. The shape of the vibration mode was obtained. Last, the load characteristics of the USM are measured using ex-perimental method. The maximum stall torque and the no-load speed were obtained. The results showed that the characteristics of the two-sided USM are better than those of the conventional one-sided USM.     

Students’ Perceptions of High School Science: What has Changed Over the Last Decade?

This paper presents comparative questionnaire data from three different samples of Australian high school students in an attempt to see if anything has changed in relation to how they perceive the science they experience in the compulsory years of secondary school (grades 7–10). Questionnaire data were obtained from 1,585 high school students in 2011 and 2,016 students in 2005 and findings are compared with those reported in a national report (Goodrum et al. 2001). Results show significant increases in the frequency with which students report that their science teacher takes notice of their ideas and in the use of computers and the Internet. There have also been changes regarding the rapid provision of feedback, the use of understandable language by teachers and the contextualisation of the new work in terms of work already covered. Little appears to have changed, however, in relation to the teacher-directed pedagogies employed to teach science where there appears to be a higher incidence of copying notes and fewer opportunities for students to investigate topics in which they are interested. The findings suggest that while there have been some positive changes, there are still many students who indicate that the science they experience in secondary school is irrelevant to their everyday life and to their future. It seems that the curiosity and wonder one would hope is associated with studying science is missing for a large proportion of students. It is clear that further actions need to be undertaken to transform this continuing situation.     

Confronting Challenges to the Liberal Arts Curriculum: Perspectives of Developing and Transitional Countries

Contemporary international higher education scholarship tends to focus on the global financial crisis,on massification,privatization,cross-border education,university ranking,and student mobility.However,few studies deal with the development of liberal arts programs around the world and they are often related to Western systems of higher education or that of the US,where liberal arts education has long been seen as a fundamental issue.Comparative studies,however,could help scholars to become aware of critical trends and reforms,also the impact they might have on a global society.     

Expectancies as mediators in the differential-reward conditional discrimination performance of pigeons

In a series of within-subject experiments employing a two-choice delayed conditional discrimination task, pigeons chose correctly more often when kind of correct choice and kind of reinforcer were perfectly correlated than when uncorrelated. Correct choice behavior fell to chance levels when the correlation was reversed or when it was removed by using only one kind of reinforcer. Implications for mediation theories are discussed, with the conclusion being that, although the possibility that instrumental mediators are present in this situation cannot be dismissed, the overall pattern of results indicates that classical mediators are of principal importance in this type of task.     

Population density and nonaggressive competition

The Calhoun (1962) paper has become a keystone article for the population density literature. Although a few research reports have followed, several aspects of population density and the behavioral phenomena identified by Calhoun have been ignored. For example, the consummatory behavior in-aggregate property of the behavioral sink is an unstudied phenomenon. Furthermore, although the literature on potential population reduction mechanisms has grown rapidly, the mechanisms of pup mortality (cannibalization by adults) as identified by Calhoun has not been pursued systematically. Finally, the question of whether social or spatial density or other factors constitute the potent variables in the development of social pathology has not been tested directly. The purpose of these five related experiments was to investigate aspects of these behaviors.     

Similarity of science textbooks: A content. Analysis

The investigator completed a content analysis of the astronomy portion of science texts at three grade levels (4th, 5th, and 6th) that were produced by five different publishers. The analysis used an operant paradigm and compared the responses expected of students who used one science text to those expected of students using other science texts. The response comparisons were made both within and across grade levels. Using similarity of the responses expected of students as a basis of comparison, elementary school science texts produced by different publishers had more in common across grade levels than within grade levels. Less than 50% of the responses expected of students at one grade level were common to other science texts at the same or different grade levels.