Role of vitamin B12 on methylmalonyl-CoA mutase activity     

Tóshiko Takahashi-I?iguez  Enrique García-Hernandez  Roberto Arreguín-Espinosa  María Elena Flores 《Journal of Zhejiang University. Science. B》2012,13(6):423-437

Vitamin B₁₂ is an organometallic compound with important metabolic derivatives that act as cofactors of certain enzymes, which have been grouped into three subfamilies depending on their cofactors. Among them, methylmalonyl-CoA mutase (MCM) has been extensively studied. This enzyme catalyzes the reversible isomerization of L-methylmalonyl-CoA to succinyl-CoA using adenosylcobalamin (AdoCbl) as a cofactor participating in the generation of radicals that allow isomerization of the substrate. The crystal structure of MCM determined in Propionibacterium freudenreichii var. shermanii has helped to elucidate the role of this cofactor AdoCbl in the reaction to specify the mechanism by which radicals are generated from the coenzyme and to clarify the interactions between the enzyme, coenzyme, and substrate. The existence of human methylmalonic acidemia (MMA) due to the presence of mutations in MCM shows the importance of its role in metabolism. The recent crystallization of the human MCM has shown that despite being similar to the bacterial protein, there are significant differences in the structural organization of the two proteins. Recent studies have identified the involvement of an accessory protein called MMAA, which interacts with MCM to prevent MCM’s inactivation or acts as a chaperone to promote regeneration of inactivated enzyme. The interdisciplinary studies using this protein as a model in different organisms have helped to elucidate the mechanism of action of this isomerase, the impact of mutations at a functional level and their repercussion in the development and progression of MMA in humans. It is still necessary to study the mechanisms involved in more detail using new methods.  相似文献   

Rolling: A new technique for the practical teaching in computer science university degree     

Irene Luque Ruiz  Miguel ángel Gómez-Nieto 《Education and Information Technologies》2012,17(1):49-77

In this paper we describe a new methodology for practical teaching in the Computer Science University Degree. The methodology is based on the Rolling technique. This technique consists in assign, in a rotary process, tasks, activities and responsibilities to students along an established calendar with the aim of developing a software product. Practical teaching is supported by a student-teacher contract that describes the goal, rules, plan with stages and activities, responsibilities and even the assessment method. Students are organized in groups and teams, emulating a company organization. They develop all the activities of the software engineering process in order to obtain a commercial product (the goal). In this process, students take different responsibilities over the software verification and validation, activities and tasks, and over groups and teams leadership. Along the teaching process, comprehensive information about the working team, time invested, deliverables in each stage, and work/students assessment is gathered. The methodology has been tested for 4 years at the University of Córdoba and the results, described in this paper, have shown an improvement in the students learning as well as in the acquisition of attitudes and skills mandatory for their professional development.  相似文献   

Teachers’ implicit theories of intelligence: influences from different disciplines and scientific theories     

Anna-Carin Jonsson  Dennis Beach  Helena Korp  Peter Erlandson 《欧洲师范教育杂志》2012,35(4):387-400

A sample of 226 Swedish high school teachers from various knowledge domains completed self-report measures of intelligence regarding implicit theories and scientific theories of intelligence. A mixed ANOVA showed that teachers from language, social science and practical disciplines had a significant preference for an incremental theory of intelligence compared to an entity theory of intelligence whilst the teachers in mathematics did not. One of the conclusions was that entity theories of intelligence may be more pronounced among teachers in mathematics. Second there is a significant relation between naïve beliefs in intelligence as fixed and inborn, entity theories, and the scientific g-factor theory. Last, it was the oldest and most experienced and youngest and least experienced teachers who preferred an entity theory of intelligence the most.  相似文献   

An integrated approach to develop professional and technical skills for informatics engineering students     

João M. Fernandes  Natascha van Hattum-Janssen  António Nestor Ribeiro  Victor Fonte  Luís Paulo Santos  Pedro Sousa 《European Journal of Engineering Education》2012,37(2):167-177

Many of the current approaches used in teaching and learning in engineering education are not the most appropriate to prepare students for the challenges they will face in their professional careers. The active involvement of students in their learning process facilitates the development of the technical and professional competencies they need as professionals. This article describes the organisation and impact of a mini-conference and project work – the creation of a software product and its introduction in the market – aimed at the development of professional competencies in general and writing skills in particular. The course was evaluated by assessing the students’ perception of the development of a number of professional competencies through a questionnaire completed by 125 students from two consecutive year groups. The results indicate that the project work and the mini-conference had a positive impact on students’ perceptions of the development of professional competencies.  相似文献   

Reasons which influence on the students’ decision to take a university course: differences by gender and degree     

Jesús Manuel López-Bonilla  Ramón Barrera Barrera  Mª Ángeles Rodríguez Serrano  Luis Miguel López-Bonilla  Beatriz Palacios Florencio  Mª Carmen Reyes Rodríguez 《Educational studies》2012,38(3):297-308

After compulsory secondary education; many teenagers face the process of choosing a university degree. This process involves uncertainties referred to their personal abilities, interests, social expectations and professional future. The present work is aimed at determining whether the reasons behind the selection of a particular university degree differ depending on the chosen degree. Another objective is determining whether these reasons differ significantly according to gender. The sample comprises 983 students belonging to the area of social and legal sciences at the University of Seville. The obtained results reveal the existence of four main reasons behind the selection of university degrees for which significant gender-related differences were observed: easy degree, job opportunities, high wages and provision of social services. Besides, these seven reasons are observed to differ widely in six of the considered degrees.  相似文献   

Understanding factors associated with teacher‐directed student use of technology in elementary classrooms: A structural equation modeling approach     

Helena P. Miranda  Michael Russell 《British journal of educational technology : journal of the Council for Educational Technology》2012,43(4):652-666

Analyses presented here are secondary data analyses of the Use, Support and Effect of Instructional Technology study aimed at identifying predictors of teacher‐directed student use of technology (TDS) in elementary classrooms. Using data from a convenience sample of 1040 teachers nested within 81 schools in 21 Massachusetts' school districts, researchers developed a teacher‐level structural equation modeling for TDS depicting relationships between and among factors associated with TDS. Researchers relied on diffusion and adoption theories as well as prior empirical evidence to specify the hypothetical model. Evidence presented here suggests that the strongest predictors of TDS are as follows: (1) teachers' experience with technology, (2) belief that technology is beneficial to meet instructional goals, (3) perceived importance of technology for teaching and that (4) experiencing obstacles with the integration of technology appears to be one deterrent to teachers using technology in the classroom. The most important finding reported here is that two of the most important factors in increasing TDS are teachers' beliefs about the benefits of technology and perceived importance of technology for teaching.  相似文献   

The effect of a structured story reading intervention,story retelling and higher order thinking for English language and literacy acquisition     

Ana M. Cruz de Quirós  Rafael Lara‐Alecio  Fuhui Tong  Beverly J. Irby 《Journal of Research in Reading》2012,35(1):87-113

The purpose of this study was to investigate the effectiveness of structured story reading intervention, Story reTelling and higher order thinking for English Language and Literacy Acquisition (STELLA), delivered to 38 Hispanic English language learners (ELL) placed in an enhanced transitional bilingual programme over 2 years from first to second grade as compared with 34 control students placed in a typical practice transitional bilingual programme during the same time period. Both treatment and comparison ELL students' retellings of two stories in Spanish and English were measured by five story elements. Findings were that (a) students receiving intervention outperformed their comparison peers in all five story elements in English and Spanish of both stories; (b) students showed stronger ability in their native language in four of five story elements; and (c) students performed at a higher level in the narrative‐informational story than a narrative story in both languages. Educational implications are discussed.  相似文献   

Dynamics of Acculturation, Enculturation, and Ethnic Identity: Influence of Psychocultural Constructs on Conscientiousness and Expectations of Higher Education Among Latinos     

Miguel ángel Cano  Linda G. Castillo  Matthew J. Davis  Araceli López-Arenas  Juana Vaquero  Keisha V. Thompson  Isaac M. Saldivar 《International journal for the advancement of counseling》2012,34(3):231-241

This study investigated the influence of psychocultural variables (e.g., acculturation, enculturation, ethnic identity) and personality characteristics in relation to educational expectations among 345 Latino middle school students in the U.S. Results from a path model indicate that 24.4?% of the variance of educational expectations was accounted for by all predictor variables included in the model. Age, acculturation, and conscientiousness had statistically significant direct effects on educational expectations. Findings also show that elements of ethnic identity and conscientiousness mediated the association from acculturation and enculturation to educational expectations. Implications of the findings for counselors are addressed.  相似文献   

Students’ self-grading,professor’s grading and negotiated final grading at three university programmes: analysis of reliability and grade difference ranges and tendencies     

Victor M. López-Pastor  María L. Santos Pastor  Antonio Fraile Aranda 《Assessment & Evaluation in Higher Education》2012,37(4):453-464

This study was undertaken at three teacher education programmes and was designed to determine the following within each programme: (1) the reliability correlations among students’ self‐grade (SSG), the grade granted by the professor (PG) and the negotiated final grade (NFG); (2) the range and frequency of grade differences between SSG and PG; and (3) the tendency of the negotiation on NFG as compared to SSG (i.e. NFG > SSG or NFG < SSG), when SSG was not equal to PG. The samples were made up of three professors and their corresponding student groups (students, n = 100, 34 and 53, respectively), each in a different teacher education programme. The results show that there was a high reliability correlation among SSG, PG and NFG in all three programmes. Furthermore, in these programmes, the grade differences were never higher than 1.5 on a scale of 0 to 10 points; in fact, agreement between DDG and PG was reached 96%, 35.29% and 43.39% of the time), and, when disagreement emerged, it was mainly within a minimum range of 0.1 to 0.5 points. As for the tendency of NFG versus SSG in each programme, slightly higher percentages were obtained for NFG > SSG in Programmes B and C, whereas the opposite (NFG < SSG) was true in Programme A; overall, however, it could be said that both tendencies balanced each other out, being the total percentages in each programme 0%, 41% and 30% for NFG > SSG; and 4%, 23% and 26%, for NFG < SSG, respectively.  相似文献   

A further step forward in measuring journals’ scientific prestige: The SJR2 indicator     

Vicente P. Guerrero-Bote  Félix Moya-Anegón 《Journal of Informetrics》2012,6(4):674-688

A new size-independent indicator of scientific journal prestige, the SJR2 indicator, is proposed. This indicator takes into account not only the prestige of the citing scientific journal but also its closeness to the cited journal using the cosine of the angle between the vectors of the two journals’ cocitation profiles. To eliminate the size effect, the accumulated prestige is divided by the fraction of the journal's citable documents, thus eliminating the decreasing tendency of this type of indicator and giving meaning to the scores. Its method of computation is described, and the results of its implementation on the Scopus 2008 dataset is compared with those of an ad hoc Journal Impact Factor, JIF(3y), and SNIP, the comparison being made both overall and within specific scientific areas. All three, the SJR2 indicator, the SNIP indicator and the JIF distributions, were found to fit well to a logarithmic law. Although the three metrics were strongly correlated, there were major changes in rank. In addition, the SJR2 was distributed more equalized than the JIF by Subject Area and almost as equalized as the SNIP, and better than both at the lower level of Specific Subject Areas. The incorporation of the cosine increased the values of the flows of prestige between thematically close journals.  相似文献