Search

This study aims to develop mathematical anxiety instruments of elementary school students in Singkawang that have good validity and reliability and can be applied in accordance with conditions in Indonesia. The subjects of this study were 710 Elementary School students in Singkawang. With the use of math anxiety questionnaire, it is hoped that it can be used as a measuring tool for teachers to find out students' mathematics anxiety. The method used in this research is R & D which is conducted for 1 year. The research design that was designed as a 4D development model without Dissemination stages, namely Define, Design and Develop. Data were analyzed through testing validity, reliability, and confirmatory factor analysis. The results of the confirmatory factor analysis show that students' mathematical anxiety instruments need to make some changes/improvements in accordance with the suggestions and various considerations before the students' mathematical anxiety instruments are used. Therefore, it is necessary to conduct further research to obtain the desired student's mathematical anxiety instrument. [ABSTRACT FROM AUTHOR]

This paper mainly focuses on the isolation and screening of actinomycetes from the south coast of Yogyakarta, which has bioactivity against plant pathogenic fungi. Actinomycetes with bioactivity against Phytophthora palmivora, a plant pathogenic fungus that causes fruit rot disease, was isolated and screened. The medium used for the isolation was starch casein mixed with antifungal compound of nystatin (25 µg/mL) and cycloheximide (75 µg/mL). The samples were pretreated by heating them for 15 minutes at 65℃. Bioactivity assay of the plant pathogenic fungi was conducted using the disc diffusion agar method. From the experiment, 36 isolates were obtained from 30 sediment samples. Two isolates, RS001.05, and RS003.04 showed inhibitory activity against the growth of the cocoa plant pathogenic fungi Phythopthora palmivora. RS001.05, which showed higher activity, was selected to be identified using DNA molecular identification. Microbial identification and characterization showed that RS.001.05 was actinobacteria, part of the genus Streptomyces, and part of the Streptomyces sp. with a homology was 99%. The phylogenetic tree showed that RS001.005 isolate was part of the same group as Streptomyces indonesiensis and Streptomyces malaysiensis. [ABSTRACT FROM AUTHOR]

This work aims to evaluate the antioxidant properties of an ethanolic extract of Sargassum polycystum C.A. Agardh. (EES) harvested from Lange coastal area (Aceh Besar). The bioactivity was estimated by conducting 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay followed by phenolic content measurement and infrared (IR) spectroscopy analysis to characterise the possible phytochemicals of the crude extract. The EES demonstrated a stronger free radical scavenging activity expressed in IC50 value of 2.178±0.117 µg/mL compared to other studies in the same species. Furthermore, the phenolic-related component was confirmed based on its phenolic content of 18.572±0.106 mg GAE/g and IR spectroscopy wavenumber of 3367.71 and 1624.06 cm−1 reflecting hydroxyl groups and aromatic rings, respectively. According to the finding, the brown algae from Lange could fairly be considered as a natural resource of antioxidants and phenolic bioactivities. [ABSTRACT FROM AUTHOR]