Judul: Seleksi bakteri endofit untuk pengendalian penyakit rebah kecambah (Pythium sp.) pada tanaman mentimun
Abstrak: Damping-off is one of the major diseases that often attack almost any plants in the nursery phase. Cucumber is one of the main hosts for damping-off disease caused by Pythium sp. The use of biocontrol agents such as endophytic bacteria is one an alternative for controlling plant diseases. The objective of this study was to isolate an endophytic bacteria from betel and paddy and to select their potency in controlling damping-off disease on cucumber. The isolation of endophytic bacteria was carried out through surface sterilization method with 70% alcohol, 4% NaOCl and sterile distilled water. A total of 50 isolates of endophytic bacteria were isolated from the betel and two isolates from the paddy. Based on antibiosis test result, growth and suppression of endophytic bacteria against damping-off, four isolates AS2, BS14, Ci6, and Ci10 were known to have ability in suppressing the disease severity of damping-off up to 87.6% and able to increase the plant growth of cucumber in a greenhouse.
Keyword: plant growth., antibiosis, sterilization method, stem, root, paddy, Bete

Judul: Formulasi Pelet Berbahan Aktif Trichoderma sp. untuk Pengendalian Penyakit Rebah Kecambah (Pythium sp.) pada Tanaman Mentimun
Abstrak: Cucumber (Cucumis sativus Linn. ) is an important agricultural comodity in Indonesia, but the production rate of it still low. One of the factors that causes the low productivity is plant diseases. Damping-off disease often causes the damage of cucumber plant, early stage of cucumber plant growth. It is caused by Phytium sp, a fungus that lives in the soil as soilborne disease. The controlling effort of this disease have been done, for example by using Trichoderma sp. as bio-agent, but the utilization of the bio-agent still not practical so it is difficult to be applied in field. The utilization of Trichoderma sp as a pallet formulation is more effective to be implemented because of the small size and easily moved. The purpose of this research is to produce the pellet formulation with active material of Trichoderma sp. with high nutritious, cheap and easy carrier. This research uses two tests, invitro and invivo. The invitro test uses six different pellet formulations, DAT, UAT, TAT, PAT, DDS and ATS. The best formulation in invitro test byare UAT and DDS because Trichoderma sp can grow very well in these pellet formulation and the raw material of them are cheap and easily obtained. The DDS and UAT can suppress the attack of pathogenic fungus, Pythium sp. on the test with invivo
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Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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