Indonesian people still consume a lot of corn as a staple food. Corn productivity based on data from the Indonesian Central Bureau of Statistics from 2005 to 2015 is not stable. Therefore this study was conducted to determine the right prediction model to see the level of corn productivity in Indonesia for the coming year, with the hope that the government has a reference to continue to work to improve corn productivity to remain stable in order to meet the needs and minimize corn imports. This study uses data on corn productivity in 2005-2015 sourced from the Indonesian Central Bureau of Statistics. The algorithm used to determine the prediction model is the Backpropagation artificial neural network. This algorithm is able to predict times series data. Based on this algorithm, the training and testing process is carried out using 5 network architecture models, namely 5-25-1, 5-43-1, 5-76-1, 5-78-1 and 7-128-1. The best architecture obtained from the 5 models is 5-25-1 with 88% accuracy percentage and MSE value 0, 00992433.

AbstrakPenelitian ini bertujuan untuk mengetahui viabilitas isolat bakteri kitinolitik dalam beberapa media pembawa dan mengetahui potensi isolat bakteri kitinolitik pada berbagai media pembawa dalam mengendalikan penyakit rebah kecambah yang disebabkan oleh F. oxysporum dan S. rolfsii pada tanaman cabai merah. Metode yang digunakan dengan mengukur viabilitas dan kemampuan bakteri dalam media tumbuh dan media pembawa pada media MGMK setelah penyimpanan media pembawa selama 90 hari. Bakteri NR09 memiliki viabilitas yang baik pada media pembawa gambut dan janjang kelapa sawit dan memiliki potensi dalam menghambat serangan jamur patogen S. rolfsii dan F. oxysporum. Kata kunci: NR09, Fusarium oxysporum, Sclerotium rolfsii , Gambut, Kompos Janjang Sawit Abstract This study was aims to determine the viability of chitinolytic bacterial isolates in some carrier media and to know the potential of chitinolytic bacterial isolates in various carrier

Assay of chitinolytic bacterial isolate of Bacillus sp. Bk17 in peat and palm oil bunch compost as carrier media in inhibiting Sclerotium rolfsii and Fusarium oxysporum of chilli seedlings. Sclerotium rolfsii and Fusarium oxysporum have been known as causal agents of seedling-off of chilli. Biological control has been used as an alternative control to replace chemical control. This study was aimed to determine the viability and ability of chitinolityc bacteria Bacillus sp. BK17 in carrier media of peat and palm oil bunch compost and in growing media to control seedling-off caused by S. rolfsii dan F. oxysporum of chilli. Our previous study showed that Bacillus sp. BK17 could reduce disease severity and intensity. Bacterial viability was measured as colony number grown after 90 days of storage in minimum salt medium with colloidal chitin as sole C source. Reduction of disease infection was measured as seedling number infected by S. rolfsii dan F. oxysporum. Seedling performances were measured as seedling height, leaf number and dry-weight after 30-days of growth. The result showed that bacterial cell viability was still high in both peat and palm oil bunch compost both with and without colloidal chitin addition after 90 days of storage. It was also shown that during application bacterial cell could grow. Seedling performaces i.e. seedling height, leaf number and dry-weight showed to be normal or even increase compared to those of pathogenic fungal inoculation only and (-) control.

A study about the antimicrobial activity test of black tea ethanol extract (Camellia sinensis) against Pseudomonas aeruginosa has been carried out. The black tea leaves are sourced from Sidamanik Plantation, North Sumatra. The dried black tea leaf extract was obtained by maceration technique in which black tea leaves were macerated for 24 hours. Then, the macerate was concentrated to obtain a thick extract and make sure that the ethanol had evaporated. After that, the concentrated extract was made with a variation of 5%, 10% and 15%. The antimicrobial activity test used was the disc method, where distilled water was used as a negative blank. The results obtained for average SD for blank with diameter 6 mm, 5%, 10% and 15% extracts were 6 ± 0,00; 7,75 ± 0,35; 9,05 ± 0,07 and 9,95 ± 0,07 mm with the inhibition diameter 0 mm; 1,75 ± 0,35; 2,05 ±0,07 and 3,95 ± 0,07 mm. The conclusion of this study is that the concentration of the extract is straightly proportional to its inhibitory power, namely the higher the concentration of black tea ethanol extract, the higher its inhibitory activity against Pseudomonas aeruginosa, so it can be used as an antibacterial agent for Pseudomonas aeruginosa.

The research was conducted aimed at knowing the effect of the Problem Based Learning model with Mind Mapping techniques influencing critical thinking skills and metacognitive knowledge of junior high school students. The sample of this study was class IX in SMP Negeri 1 Ronggur Nihuta which was taken by random sampling with the number of students 62. The instrument of this research was a test. This research method is descriptive and data analysis techniques using the t test with a significance level α = 0.05. The results showed that the influence of the Problem Based Learning model with Mind Mapping techniques had an effect on students' critical thinking skills (tcount 90.66> t table 2.039); (2) There is the influence of the Problem Based Learning model with the Mind Mapping technique affecting the metacognitive knowledge of students (t count 40.68> t table 2.039). The results of this study imply that the level of critical thinking skills, metacognitive knowledge has an important role in improving the learning outcomes of junior high school students.