Judul: Isolasi dan Seleksi Bakteri Berpotensi Sebagai Pemicu Pertumbuhan Tanaman
Abstrak: This study aims to collect bacterial isolates potentially such as; solubilizing bacterial phosphate, cellulose decomposer, and N2 fixer (Azospirillum). Stages of research include the isolation and purification; Selection BPF (qualitative test, quantitative), CPM (cellulolytic index), Azospirillum (Kjeldahl method); bacterial testing (hypersensitivity test, hemolytic test, bacterial antagonism test). The results showed that the best BPF isolates with the biggest IP and the P-value was BPF3.2.1 and BPF2.1.1 isolates. The best isolates of best CPM in producing cellulose with highest is value was BPS2.1.1 and BPS3.5 isolates. The best Azospirillum isolates which able to fix N2 was AZ3.2 and AZ2.4 isolates. Isolates BPS3.5 BPF2.1.1 and AZ3.2 indicated to show have antagonistic when were grow in the same plate . All isolates were not pathogenic to plants. However, isolates AZ3.2 and BPS2.1.1 potentially pathogenic to animals.
Keyword: Bogor Agricultural University (IPB), patogenitas, BPS, BPF, Azospirillum, antagonistic

Judul: Uji Efektivitas Bakteri Pemicu Tumbuh Tanaman Penyusun Pupuk Hayati Provibio.
Abstrak: The use of biofertilizers is expected to improve soil health, stimulate plant growth and increase crop production. In connection with the utilization of microbial biofertilizers, quality testing needs to be done periodically to maintain the quality of biofertilizers. This study aims to evaluate the effective of plant growth promoting bacteria at Provibio biofertilizer. The stages of this research are strains testing of plant growth promoting bacteria which includes purification, testing the potency of bacteria, pathogenicity test, antagonism test, characterization and identification, the calculation of the total population for each strain of bacteria in mixed cultures. The results show that plant growth promoting bacteria inoculan real in increase plant growth, but does not significant effect in increasing root length, wet weight and dry weight of plant compared to controls. ICBB 6099 isolate potentially pathogenic to humans or animals. ICBB 6088 shown antagonistic characteristic on ICBB 6099 isolate when combined in vitro. ICBB 6099 isolate has similar characteristics to the genus Listeria. Whereas ICBB 8767 isolate which has similar characteristics to the genus Phenylobacterium and Aeromicrobium. ICBB 8767 has highest density of populations in the mixed cultures.
Keyword: effectivity test, pathogenicity, identification, plant growth promoting bacteria, antagonism

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.
Keyword: