Penerapan Model Pembelajaran Relating, Experiencing, Applying, Cooperating, and Transferring (React) Terhadap Motivasi Dan Hasil Belajar Dalam Pembelajaran Fisika Di SMA

The model of learning is a learning model that REACT can help teachers to inculcate concepts in students. Students are invited to find itself a concept study, in cooperation, applying those concepts in everyday life and transfer in new condition. The study was conducted based on the results of the initial observations where there are problems of lack of motivation of students to attend lessons, learning achievements of students resulting in decreased. The purpose of this study was to examine the differences in the results using a model Relating physics learning, Experiencing, Applying, Cooperating, and Transferring (REACT) with models Direct learning Intruction (in). It also Mendiskripsikan the motivation of learning students during the learning process using a model Relating, Experiencing, Applying, Cooperating, and Transferring (REACT) in high school. Data collection techniques used in this research is the observation, documentation, interviews and tests. The data obtained is an assessment of observer and post-test which is the student learning outcomes, the value of motivation and now test the delay was the result of learning motivation of students. Data analysis using Independent Samples T-test to answer the first problem formulation. The results of research and analysis of the data shows that the test results of the Independent Samples T-test acquired Sig. (2-tailed) $ 0,022 < 0.05. This shows that there is a significant learning outcome differences between students in learning using models REACT by using the Direct model Intruction (in). The second issue in the analysis using question form of motivation. The result of the percentage of the average for all the indicators in question form is the motivation of 82,7%, on the basis of those results can be drawn the conclusion that learning Physics by using model Relating, Experiencing, Applying, Cooperating, and Transferring (REACT) positive impact on students ' learning motivation

The effect of vitamin e antioxidant addition in goat milk diluent on the quality of thin-tailed sheep semen

Artificial insemination supports the prevention of infectious dispersion in organisms which share the same environment. Meanwhile, spermatozoa usually experience a decrease in quality during processing due to the peroxidation process. This study aims to identify the effect of vitamin E antioxidant addition in goat milk diluent on the quality of thin-tailed sheep semen after storing at 5°C for five days. A total of 4 male thin-tailed sheep were used and the treatments consisted of controls, namely goat milk sperm diluent without vitamin E antioxidant (P0), and others with the addition of vitamin E at a dose of 2 gL-1 diluent (P1); 3 gL-1diluent (P2); and 4 gL-1 (P3). Moreover, the variables observed include individual motility, viability, and intact plasma membrane of spermatozoa after storing at 5°C for five days. The data were analyzed statistically using analysis of variance (ANOVA) with a completely randomized design in one-way. The results showed that the addition of vitamin E antioxidant to goat milk diluent during sperm dilution had a significant effect (P < 0.05) on the motility, viability, and intact plasma membrane. Spermatozoa motility at P0, P1, P2, and P3 were 44.0, 48.2, 50.4, and 53.2, while the viability was 48.2, 51.4, 54.2, and 56.0, respectively. Additionally, the intact plasma membranes at P0, P1, P2, and P3 were 41.0, 46.6, 48.2, and 51.4, respectively. The addition of antioxidant vitamins in goat milk diluent with a concentration of 4 gL-1 produced the best results on sperm quality after cooling. Based on the results, it was concluded that the addition of vitamin E antioxidant to the sperm diluent can improve the quality of thin-tailed sheep chilled semen. © Published under licence by IOP Publishing Ltd

The crystal structure of an extracellular catechol oxidase from the ascomycete fungus Aspergillus oryzae

Catechol oxidases (EC 1.10.3.1) catalyse the oxidation of o-diphenols to their corresponding o-quinones. These oxidases contain two copper ions (CuA and CuB) within the so-called coupled type 3 copper site as found in tyrosinases (EC 1.14.18.1) and haemocyanins. The crystal structures of a limited number of bacterial and fungal tyrosinases and plant catechol oxidases have been solved. In this study, we present the first crystal structure of a fungal catechol oxidase from Aspergillus oryzae (AoCO4) at 2.5-Å resolution. AoCO4 belongs to the newly discovered family of short-tyrosinases, which are distinct from other tyrosinases and catechol oxidases because of their lack of the conserved C-terminal domain and differences in the histidine pattern for CuA. The sequence identity of AoCO4 with other structurally known enzymes is low (less than 30 %), and the crystal structure of AoCO4 diverges from that of enzymes belonging to the conventional tyrosinase family in several ways, particularly around the central α-helical core region. A diatomic oxygen moiety was identified as a bridging molecule between the two copper ions CuA and CuB separated by a distance of 4.2–4.3 Å. The UV/vis absorption spectrum of AoCO4 exhibits a distinct maximum of absorbance at 350 nm, which has been reported to be typical of the oxy form of type 3 copper enzymes