Collaborative and Cooperative Learning in Malaysian Mathematics Education

Collaborative and cooperative learning studies are well recognized in Malaysian mathematics education research. Cooperative learning is used to serve various ability students taking into consideration of their level of understanding, learning styles, sociological backgrounds that develop students' academic achievement and skills, and breeze the social harmony among students of different ethnic backgrounds. Besides academic achievement, process skills and values are required to extend the social harmony among students in today's multiethnic schools. Therefore, teachers are expected to find the pedagogy that enables students to learn academic knowledge and professional skills to face the challenges in their everyday lives. The Malaysian scholars, based on the findings of their cooperative learning studies, emphasized the use of cooperative learning as an effective pedagogy with the aim to improve students' mathematics achievement and communication skills. This paper describes the role of collaborative and cooperative learning to the development of students' mathematics achievement along with their communication skills and with significant integration of values in Malaysian mathematics education

2MASS Studies of Differential Reddening Across Three Massive Globular Clusters

J, H, and K_S band data from the Two Micron All-Sky Survey (2MASS) are used to study the effects of differential reddening across the three massive Galactic globular clusters Omega Centauri, NGC 6388, and NGC 6441. Evidence is found that variable extinction may produce false detections of tidal tails around Omega Centauri. We also investigate what appears to be relatively strong differential reddening towards NGC 6388 and NGC 6441, and find that differential extinction may be exaggerating the need for a metallicity spread to explain the width of the red giant branches for these two clusters. Finally, we consider the implications of these results for the connection between unusual, multipopulation globular clusters and the cores of dwarf spheroidal galaxies (dSph).Comment: 40 pages, 14 figures. Accepted for publication in Oct. 2003 A

Effect of compression on the acoustic absorption of coir fiber

Problem statement: The absorption characteristics of coir fiber were analyzed previously. Analytical method to predict the acoustical behavior of coir fiber has already been developed. However, compression effects of coir fiber were not explored which might significant for acoustics absorption during seat padding. In this study, compression effect on the sound absorption characteristics of coir fiber are demonstrated based on the previous analytical approach such as rigid frame method with the modification in the physical parameters. Approach: The verification of the estimated acoustical absorption coefficient in uncompressed condition using rigid frame Johnson- Allard Model are shown for three different thicknesses of industrially processed coir fiber mixed with binder latex. Measurements were conducted in impedance tube on normal incidence sound absorption of coir fiber. It is well known that the absorption behavior of a porous material varies during compression and affects the physical parameters. In these analyses, formulas proposed by Castagnede are employed to predict the compression effect on the absorption of coir fiber which takes into account the modifications of the physical parameters during compression. Results: The agreement between the analytical and measured results is justified for all three sample thicknesses in uncompressed condition. Analyses on the acoustic behavior of material during compressed condition show that compression has a substantial effect on the absorption of coir fiber. It also indicates that the absorption of coir fiber can be enhanced by compressing the material. In addition, the absorption performances are compared by varying the compression rate on material at uncompressed and compressed condition. Conclusion: From overall analyses, it is evident that compression of coir fiber can significantly change the absorption behavior of coir fiber from the actual acoustical characteristics as estimated at normal condition. Moreover, compressing the material might be considered as a possible approach to improve the absorption coefficient of coir fiber. An additional example is presented to show a potential way of enhancing absorption coefficient of coir fiber utilizing compression effect.Mohd Jailani Mohd Nor, Md. Ayub, Rozli Zulkifli, Nowshad Amin and Mohammad Hosseini Foulad

Collaborative and Cooperative Learning in Malaysian Mathematics Education

Collaborative and cooperative learning studies are well recognized in Malaysian mathematics education research. Cooperative learning is used to serve various ability students taking into consideration of their level of understanding, learning styles, sociological backgrounds that develop students' academic achievement and skills, and breeze the social harmony among students of different ethnic backgrounds. Besides academic achievement, process skills and values are required to extend the social harmony among students in today's multiethnic schools. Therefore, teachers are expected to find the pedagogy that enables students to learn academic knowledge and professional skills to face the challenges in their everyday lives. The Malaysian scholars, based on the findings of their cooperative learning studies, emphasized the use of cooperative learning as an effective pedagogy with the aim to improve students' mathematics achievement and communication skills. This paper describes the role of collaborative and cooperative learning to the development of students' mathematics achievement along with their communication skills and with significant integration of values in Malaysian mathematics education

Produção de antissoro policlonal utilizando a proteína capsidial recombinante do Rupestris stem pitting-associated virus.

O Rupestris stem pitting-associated virus (RSPaV) é o agente causal das caneluras do lenho da videira. Este trabalho teve como objetivo produzir antissoro policlonal a partir da proteína capsidial (CP) recombinante do RSPaV e avaliar a sua especificidade e sensibilidade. O gene da CP do RSPaV, com 780pb, foi previamente caracterizado. Esse gene foi subclonado no sítio de restrição EcoRI, no vetor de expressão pRSET-B e o plasmídeo recombinante foi utilizado para induzir a expressão da CP em Escherichia coli. A CP, ligada a uma cauda de seis histidinas, foi purificada por meio de cromatografia de afinidade em coluna de Ni-NTA a partir do extrato de proteínas totais extraídas de E. coli. A identidade da proteína purificada foi confirmada em SDS-PAGE e Western blot, utilizando-se anticorpos comerciais contra a cauda de seis histidinas. A CP recombinante expressada in vitro apresentou massa molecular de cerca de 31kDa. A proteína purificada foi quantificada e 2,55mg foram utilizados para a imunização de um coelho. O antissoro policlonal obtido reagiu com diferentes isolados deste vírus, extraídos de videiras em ELISA indireto.Nota técnica

Length-weight relationships of 13 fish species from Pahang River, Temerloh district, Pahang, Malaysia

Length–weight relationships (LWRs) are described for 13 fish species from Pahang River, Temerloh district, Pahang, Malaysia. The river serves as a main water body for freshwater aquaculture in the country and also supplies various fishes for local consumption. This is the first record of LWRs for nine fish species and new maximum lengths for three species in fishbase

Biodegradação de glifosato pela microbiota de solos cultivados com macieira.

Resumo: O glifosato é um herbicida sistêmico, pós-emergente, não seletivo do grupo dos organofosforados, sendo amplamente usado em pomares de macieira no sul do Brasil, podendo causar consequências negativas para microrganismos benéficos do solo. O objetivo deste trabalho foi avaliar a capacidade de biodegradação do glifosato pela microbiota de solos de pomares de macieira, com diferentes históricos de aplicação do produto. Para isso, amostras de solos da região de Vacaria, RS, foram utilizadas, cuja biodegradação do glifosato foi avaliada monitorando a liberação de CO2 pelos microrganismos durante 32 dias, bem como quantificando os resíduos de glifosato e seu metabólito, o ácido aminometilfosfônico (AMPA), no início e no final do período pela extração seguidade análise por cromatografia líquida de alta eficiência. Os resultados evidenciaram que houve degradação do glifosato pelos microrganismos edáficos durante o período avaliado com formação do metabólito AMPA. O glifosato diminuiu o número de bactérias do solo, porém favoreceu o aumento da atividade microbiana. As bactérias presentes nos solos com histórico de menor tempo de aplicação do herbicida apresentaram maior capacidade de degradação do produto, quando comparadas àquelas existentes em solos com maior período de aplicação de glifosato. Abstract: Glyphosate is a systemic post-emergent herbicide of the non-selective organophosphate group widely used in apple orchards in the South of Brazil. It may have adverse effects on beneficial soil microorganisms. The aim of this study was to evaluate the biodegradability of glyphosate by soil microbiota in apple orchards with different histories of application of the product. For that purpose, soil samples from the region of Vacaria, Rio Grande do Sul, were used, with the biodegradation of glyphosate being evaluated by monitoring the release of CO 2 by microorganisms over 32 days, as well as quantifying the residues of glyphosate and its metabolite, aminomethylphosphonic acid (AMPA), at the beginning and end of the period through extraction followed by analysis by high performance liquid chromatography (HPLC). The results showed that there was glyphosate degradation by soil microorganisms during the period evaluated, with formation of the metabolite AMPA. Glyphosate decreased the number of soil bacteria, but favored increased microbial activity. The bacteria present in soils with lower herbicide exposure showed more degradability of the product when compared to those found in soils with a greater period of glyphosate application

Effect of Compacting Pressure on Fuel Properties of Finger Millet Briquettes

In this work, the effect of compacting pressure on fuel properties of finger millet briquettes was investigated and reported. Four different varieties of finger millet namely P224, Gulu-E, U-15 and Okhale-1 were used to produce briquettes without a binder using manual hydraulic press at predetermined compacting pressure of 15, 25 and 35MPa. The proximate analysis results of the resultant briquettes was between 68-70% volatile matter, 21-24% fixed carbon, 9-11% moisture content and 7-8% ash content which is comparable with those of other biomass materials such as rice, wheat and wood. On the effect of compacting pressure on fuel properties, the study showed an increasing trend in briquette density and compressive strength as compacting pressure increased from 15 to 35MPa. However, as compacting pressure increased, the burning rate decreased due to reduced air voids in the briquettes thus limiting mass and heat transfer during combustion. Keywords: Burning rate, Briquettes, Compacting Pressure, Density, Finger Millet straw

Functional characterization of a melon alcohol acyl-transferase gene family involved in the biosynthesis of ester volatiles. Identification of the crucial role of a threonine residue for enzyme activity

Volatile esters, a major class of compounds contributing to the aroma of many fruit, are synthesized by alcohol acyl-transferases (AAT). We demonstrate here that, in Charentais melon (Cucumis melo var. cantalupensis), AAT are encoded by a gene family of at least four members with amino acid identity ranging from 84% (Cm-AAT1/Cm-AAT2) and 58% (Cm-AAT1/Cm-AAT3) to only 22% (Cm-AAT1/Cm-AAT4). All encoded proteins, except Cm-AAT2, were enzymatically active upon expression in yeast and show differential substrate preferences. Cm-AAT1 protein produces a wide range of short and long-chain acyl esters but has strong preference for the formation of E-2-hexenyl acetate and hexyl hexanoate. Cm-AAT3 also accepts a wide range of substrates but with very strong preference for producing benzyl acetate. Cm-AAT4 is almost exclusively devoted to the formation of acetates, with strong preference for cinnamoyl acetate. Site directed mutagenesis demonstrated that the failure of Cm-AAT2 to produce volatile esters is related to the presence of a 268-alanine residue instead of threonine as in all active AAT proteins. Mutating 268-A into 268-T of Cm-AAT2 restored enzyme activity, while mutating 268-T into 268-A abolished activity of Cm-AAT1. Activities of all three proteins measured with the prefered substrates sharply increase during fruit ripening. The expression of all Cm-AAT genes is up-regulated during ripening and inhibited in antisense ACC oxidase melons and in fruit treated with the ethylene antagonist 1-methylcyclopropene (1-MCP), indicating a positive regulation by ethylene. The data presented in this work suggest that the multiplicity of AAT genes accounts for the great diversity of esters formed in melon