Judul: Peningkatan ketersediaan biologis phospor dari rock phosphate dengan proses fermentasi Aspergillus niger dan pengasaman
Abstrak: Phosphorus availability of rock phosphate can be improved to be phosphorus source for poultry. The availability of phosphorus (P) in rock phosphate is limited because it less soluble in neutral PH. The experiment was conducted to find out a process that could improve the phosphorus bio-availability of rock phosphate.
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Judul: Potensi Aspergillus niger dan Penicillium spp. sebagai Endosimbion Pelarut Fosfat pada Akar Serealia
Abstrak: Aspergillus niger and Penicillium sp. are known to have the ability to solubilize phosphorus (P). P in acid soils exists in unavailable forms that decrease productivity. Indonesia has a large acid soil that used for cereal crops production. Therefore, the potential of A. niger (IPBCC 10.643) and Penicillium spp. (IPBCC 09.620 and 09.621 IPBCC) as P solubilizing endosymbiont in the roots of cereals (maize, sorghum, and rice) was studied. Endosymbiosis of P solubilizing fungi was observed in germlings that were free from endophytic fungi and planted on zeolite in acidic condition with AlPO4 as a source of P, for eight weeks period. Endosymbiosis was determined based on fungal percentage of colonization in the roots. The effects of endosymbiosis on plant growth was measured as height and dry weight of plants for four weeks, and also by efficiency of nutrient uptake in plants at eight weeks old. The results of this study indicated that A. niger and Penicillium spp. colonized the roots up to 70%, so the fungi were considered as endosymbionts. Association of A. niger and roots showed a negative effect on all test plants. Two strains of Penicillium spp. only increased the height and dry weight of sorghum and increased P uptake in maize and sorghum. The N, P, and K efficiency uptake of maize that inoculated with Peniclillium sp. IPBCC 09.620 about 1.22, 1.45, and 1.36 of the control respectively, while those inoculated with Penicillium sp. IPBCC 09.621 were 1.55, 1.52, and 1.04, respectively. Sorghum that were inoculated with Penicillium sp. IPBCC 09.620 showed the efficiency uptake of N, P, and K about 1.04, 2.00, and 1.79, respectively. This efficiency uptake of N, P, and K as relatively greater than the efficiency uptake of N, P, and K of sorghum plants (1.19, 1.30, and 1.46, respectively) that were inoculated Penicillium sp. IPBCC 09.62
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Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology