117 research outputs found
Detection of a guanine X adenine base pair in a decadeoxyribonucleotide by proton magnetic resonance spectroscopy.
Understanding Acid-Base Concepts: Evaluating the Efficacy of a Senior High School Student-Centred Instructional Program in Indonesia
This study was a mixed quantitativeâqualitative research to evaluate the efficacy of a designed student-centred instructional (DSCI) program for teaching about acids and bases. The teaching innovation was designed based on constructivist, hands-on inquiry and context-based approaches and implemented in seven 45-min lessons with a class of 36 grade 11 students (experimental group) from a public senior high school in Indonesia. Another class of 38 students (comparison group) from the same school was instructed using a traditional teacher-centred approach. Data were obtained using a (1) 12-item achievement test on acids and bases that was administered to both groups as a pretest and a posttest, (2) self-evaluation 13-item questionnaire on studentsâ perceptions of their competence and confidence in carrying out the inquiry activities that was administered to the experimental group and (3) 3-item open-ended questionnaire on studentsâ perceptions of the instructional process using the DSCI that was administered to the experimental group.The results of the study showed that the teaching innovation was effective in improving studentsâ understanding of acidâbase concepts with significant difference between the two groups on the posttest mean scores. Moreover, the effectiveness of the innovation was supported by an increase in studentsâ interest in learning science as indicated by their (1) positive perceptions of their engagement and competence in doing inquiry activities, (2) positive perceptions of the learning environment and (3) positive outcome expectations. The findings have implications for chemistry teaching in any institution with similar achieving students as well as for the professional development of teachers
Relationship Between Affect and Achievement in Science and Mathematics in Malaysia and Singapore
Background: The Trends in International Mathematics and Science Study (TIMSS) assesses the quality of the teaching and learning of science and mathematics among Grades 4 and 8 students across participating countries. Purpose: This study explored the relationship between positive affect towards science and mathematics and achievement in science and mathematics among Malaysian and Singaporean Grade 8 students. Sample: In total, 4466 Malaysia students and 4599 Singaporean students from Grade 8 who participated in TIMSS 2007 were involved in this study. Design and method: Studentsâ achievement scores on eight items in the survey instrument that were reported in TIMSS 2007 were used as the dependent variable in the analysis. Studentsâ scores on four items in the TIMSS 2007 survey instrument pertaining to studentsâ affect towards science and mathematics together with studentsâ gender, language spoken at home and parental education were used as the independent variables.Results: Positive affect towards science and mathematics indicated statistically significant predictive effects on achievement in the two subjects for both Malaysian and Singaporean Grade 8 students. There were statistically significant predictive effects on mathematics achievement for the studentsâ gender, language spoken at home and parental education for both Malaysian and Singaporean students, with R 2 = 0.18 and 0.21, respectively. However, only parental education showed statistically significant predictive effects on science achievement for both countries. For Singapore, language spoken at home also demonstrated statistically significant predictive effects on science achievement, whereas gender did not. For Malaysia, neither gender nor language spoken at home had statistically significant predictive effects on science achievement. Conclusions : It is important for educators to consider implementing self-concept enhancement intervention programmes by incorporating âaffectâ components of academic self-concept in order to develop studentsâ talents and promote academic excellence in science and mathematics
Using metacognitive strategies in teaching to facilitate understanding of light concepts among year 9 students
Background: Enhancing studentsâ metacognitive abilities will help to facilitate their understanding of science concepts. Purpose: The study was designed to conduct and evaluate the effectiveness of a repertoire of interventions aimed at enhancing secondary school studentsâ metacognitive capabilities and their achievements in science. Sample: A class of 35 Year 9 students participated in the study. Design and methods: The study involved a pre-post design, conducted by the first author as part of the regular designated science programme in a class taught by him. In order to enhance the studentsâ metacognitive capabilities, the first author employed clearly stated focused outcomes, engaging them in collaborative group work, reading scientific texts and using concept mapping techniques during classroom instruction. The data to evaluate the effectiveness of the metacognitive interventions were obtained from pre- and post-test results of two metacognitive questionnaires, the Metacognitive Support Questionnaire (MSpQ) and the Metacognitive Strategies Questionnaire (MStQ), and data from interviews. In addition, pre-test and post-test scores were used from a two-tier multiple-choice test on Light.Results: The results showed gains in the MSpQ but not in the MStQ. However, the qualitative data from interviews suggested high metacognitive capabilities amongst the high- and average-achieving students at the end of the study. Studentsâ gains were also evident from the test scores in the Light test. Conclusion: Although the quantitative data obtained from the Metacognitive Strategies Questionnaire did not show significant gains in the studentsâ metacognitive strategies, the qualitative data from interviews suggested positive perceptions of studentsâ metacognitive strategies amongst the high- and average-achieving students. Data from the Metacognitive Support Questionnaire showed that there were significant gains in the studentsâ perceptions of their metacognitive support implying that the majority of the students perceived that their learning environment was oriented towards the development of their metacognitive capabilities. The effect of the metacognitive interventions on studentsâ achievement in the Light test resulted in students displaying the correct declarative knowledge, but quite often they lacked the procedural knowledge by failing to explain their answers correctly
Consequences of a telomerase-related fitness defect and chromosome substitution technology in yeast synIX strains
We describe the complete synthesis, assembly, debugging, and characterization of a synthetic 404,963 bp chromosome, synIX (synthetic chromosome IX). Combined chromosome construction methods were used to synthesize and integrate its left arm (synIXL) into a strain containing previously described synIXR. We identified and resolved a bug affecting expression of EST3, a crucial gene for telomerase function, producing a synIX strain with near wild-type fitness. To facilitate future synthetic chromosome consolidation and increase flexibility of chromosome transfer between distinct strains, we combined chromoduction, a method to transfer a whole chromosome between two strains, with conditional centromere destabilization to substitute a chromosome of interest for its native counterpart. Both steps of this chromosome substitution method were efficient. We observed that wild-type II tended to co-transfer with synIX and was co-destabilized with wild-type IX, suggesting a potential gene dosage compensation relationship between these chromosomes. </p
Effects of a Mathematics Cognitive Acceleration Program on Student Achievement and Motivation
This paper presents the effects of a cognitive acceleration program in mathematics classes on Tongan studentsâ achievements, motivation and self-regulation. Cognitive Acceleration in Mathematics Education (CAME) is a program developed at Kingâs College and implemented worldwide with the aim of improving studentsâ thinking skills, mathematics performance and attitudes. The first author adapted the program materials to Tongan educational context and provided support to participating teachers for 8 months. This study employed a quasi-experimental design with 219 Year 8 students as the experimental group and 119 Year 8 students as the comparison group. There were a significant differences in the mean scores between the pre-test and post-test of the three instruments that were employed in the study, indicating that learning mathematics under the CAME program had a positive effect on levels of studentsâ self-regulation, motivation and mathematics achievement. Students also reported changes to the ways they learn mathematics
An overview of knowledge sharing in new product development
This paper provides an overview of some of the issues in knowledge management related to the sharing of knowledge in new product development. Previous research and concepts reported by international researchers, and examples of the research projects carried out by the authors will be introduced. The paper first provides an overview of the history and importance of innovation and challenges in manufacturing. Then the importance of new product development in the sustainable success of manufacturing enterprises in the globalised business operations is discussed. The formalisation and modelling of product development processes will also be introduced. The concept and different definitions of knowledge management by previous researchers are then introduced, with further discussion on knowledge sharing. At this point, the authorsâ research in knowledge sharing is also introduced. Finally, the trend of using social media and Enterprise 2 technologies in knowledge management and sharing is introduced using the recent research projects of the authors as examples
Attenuation of Zinc Finger Nuclease Toxicity by Small-Molecule Regulation of Protein Levels
Zinc finger nucleases (ZFNs) have been used successfully to create genome-specific double-strand breaks and thereby stimulate gene targeting by several thousand fold. ZFNs are chimeric proteins composed of a specific DNA-binding domain linked to a non-specific DNA-cleavage domain. By changing key residues in the recognition helix of the specific DNA-binding domain, one can alter the ZFN binding specificity and thereby change the sequence to which a ZFN pair is being targeted. For these and other reasons, ZFNs are being pursued as reagents for genome modification, including use in gene therapy. In order for ZFNs to reach their full potential, it is important to attenuate the cytotoxic effects currently associated with many ZFNs. Here, we evaluate two potential strategies for reducing toxicity by regulating protein levels. Both strategies involve creating ZFNs with shortened half-lives and then regulating protein level with small molecules. First, we destabilize ZFNs by linking a ubiquitin moiety to the N-terminus and regulate ZFN levels using a proteasome inhibitor. Second, we destabilize ZFNs by linking a modified destabilizing FKBP12 domain to the N-terminus and regulate ZFN levels by using a small molecule that blocks the destabilization effect of the N-terminal domain. We show that by regulating protein levels, we can maintain high rates of ZFN-mediated gene targeting while reducing ZFN toxicity
High School Students' Proficiency and Confidence Levels in Displaying Their Understanding of Basic Electrolysis Concepts
This study was conducted with 330 Form 4 (grade 10) students (aged 15 â 16 years) who were involved in a course of instruction on electrolysis concepts. The main purposes of this study were (1) to assess high school chemistry studentsâ understanding of 19 major principles of electrolysis using a recently developed 2-tier multiple-choice diagnostic instrument, the Electrolysis Diagnostic Instrument (EDI), and (2) to assess studentsâ confidence levels in displaying their knowledge and understanding of these electrolysis concepts. Analysis of studentsâ responses to the EDI showed that they displayed very limited understanding of the electrolytic processes involving molten compounds and aqueous solutions of compounds, with a mean score of 6.82 (out of a possible maximum of 17). Students were found to possess content knowledge about several electrolysis processes but did not provide suitable explanations for the changes that had occurred, with less than 45â% of students displaying scientifically acceptable understandings about electrolysis. In addition, students displayed limited confidence about making the correct selections for the items; yet, in 16 of the 17 items, the percentage of students who were confident that they had selected the correct answer to an item was higher than the actual percentage of students who correctly answered the corresponding item. The findings suggest several implications for classroom instruction on the electrolysis topic that need to be addressed in order to facilitate better understanding by students of electrolysis concepts
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