Judul: Kemampuan Bakteri Endofit Penghasil Asam Indol Asetat dan Pengaruhnya dalam Mengendalikan Virus Gemini pada Tanaman Cabai (Capsicum annum L.)
Abstrak: Production of red chilli in Indonesia decreased because of gemini virus disease. The disease is transmitted by Bemisia tabacias insect vector. One of possibility methods is to improve plant resistancecan be supported byendhopytic bacteria or Plant Growth Promoting Rhizobacteria (PGPR) which can produce IAA (Indole Asetic Acid) hormone. IAA hormone can serves as a growth promoter and plant resistance. The aims of this research are to test the effect of 50 isolates endhopytic bacteria producing hormones in the IAA and analyze the effect on growth of chilli plants that Gemini virus. The experimental design was factorial randomize complete block design which three AIA treatment and two variety of chilli treatments as factors. These treatments were replicated in five blocks. The results showed that infection by Gemini virus could reduce and increase plant growth.
Keyword: Gemini virus, productivity, Plant Growth Promoting Rhizobacteria, endophytic bacteria, chilli, hormone

Judul: Pengaruh aplikasi bakteri perakaran pemacu pertumbuhan tanaman pada tiga genotipe cabai (Capsicum annum L.) terhadap pertumbuhan tanaman serta kejadian penyakit penting cabai
Abstrak: In Indonesia, chilli was an important vegetable commodity refer to production area as well as it’s value, but production of chilli in Indonesia still very low. The low production was caused by a lack of proper cultivation techniques, seed quality, and pest and plant disease. Important disease that can decrease the production of chilli includes antrachnose disease, bacterial wilt, mosaic and mottle virus in chilli. The disease controlling effort that were recently developed and relatively safe for the environment, using Plant Growth-promoting Rhizobacteria (PGPR). The objective of this study was to determine the effect of PGPR usage, that were P. fluorescens PG01 isolates, B. polymixa BG25 and a mixture of both isolates (PG01 + BG25) against agronomic characters and incidence of important diseases in the three genotypes of chilli (IPB C5, C10 IPB, and Kopay) on the field. The experiment was performed from February until November, 2009 on farmer land were located on Desa Cibatok I, Kecamatan Cibungbulang, Kabupaten Bogor. The experiment was arranged in split plot design, were randomly treated with bacterial group as main plots and genotypes as subplots. Four levels main plots were PGPR treatments isolates PG01, BG25, PG01 + BG25, and without PGPR treatment as a comparison. The three subplots were C10 IPB, C5 IPB, and Kopay. In the experiment there were 12 treatment combinations, each treatment consisted of three replications, so there are 36 experimental units. Each experimental unit consisted of 20 plants, with a total 720 plants were tested. PGPR treatments significantly influenced the plant height and number of branches, but gave no significant effect on leaves number. The highest growth improvement on vegetative phase was occurred by the mixed bacterial treatment (PG01 + BG25). IPB C10, C5 genotypes and varieties of IPB Kopay have different agronomic characteristics measured on plant height, number of branches and number of leaves. PGPR treatment did not affect significantly to crop production and disease incidence (antraknosa, bacterial wilt, TMV, CMV, and ChiVMV). Antrachnose infections most commonly found in Kopay varieties, while the bacterial wilt infection occurs more frequently in genotypes IPB C5.
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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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