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: Isolasi dan seleksi bakteri filosfer pemicu tumbuh dari daun padi (Oryza sativa L. var. IR-64)
Abstrak: Penelitian ini bertujuan untuk mengisolasi bakteri filosfer pemicu tumbuh dan mendapatkan bakteri filosfer unggul yang mampu meningkatkan pertumbuhan tanaman pada skala laboratorium. Parameter yang diukur meliputi: tinggi tanaman pada uji benih (2 MST-5 MST), tinggi tanaman pada uji daun (4 MST - 5 MST). Bobot basah dan bobot kering tanaman bagian atas, dan bobot basah dan bobot kering akar Percobaan dilakukan berdasarkan Rancangan Acak Lengkap (RAL) dengan tiga kali ulangan dan dilanjutkan dengan uji lanjut Duncan. Isolat bakteri yang berhasil diisolasi dari permukaan daun padi terdiri dari 19 solat, dimana sembilan isolat berasal dari desa Pasir Kuda, Ciomas, Bogor (C). sepuluh isolat berasal dari desa Ciherang, Sindang Barang, Bogor (S). Sebelas isolat terdapat pada filosfer (A), dan delapan isolat terdapat pada endofilosfer (B) Dua isolat diambil dari daun berumur 2 MST (X), sembilan isolat berasal dari daun berumur 4 MST (Y), dan delapan isolat berasal dari daun berumur 8 MST (Z). Hasil penelitian menunjukkan bahwa inokulasi isolat filosfer sangat nyata meningkatkan tinggi tanaman pada uji benih. Pada uji daun, pengaruh inokulasi isolat filosfer nyata pada 4 MST dan sangat nyata pada 5 MST. Pengaruh inokulasi terhadap bobot tanaman secara umum berpengaruh nyata meningkatkan bobot tanaman dibandingkan kontrol. Isolat yang berasal dari hasil isolasi tanaman berumur muda (X) cenderung menunjukkan pertumbuhan yang lebih rendah dibandingkan isolat lainnya terhadap pertumbuhan tanaman padi Dari semua isolat, terdapat 6 isolat terpilih, yaitu isola SAYS diklasifikasikan ke dalam genus Bacillus, Isola SAY3 diklasifikasikan ke dalam genus Arthrobacter, Isolat CBZ9 dan Isolat SBZ10 termasuk kedalam genus Microbacter, dan Isolat CBZ8 dan isolat SBY8 termasuk kedalam genus Celluloos.
Keyword: Oryza sativa, phyllosphere bacteria, isolate inoculation

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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