Judul: Dampak Aplikasi Pgpr Pada Kacang Panjang Terhadap Biologi Dan Statistik Demografi Aphis Craccivora Koch (Hemiptera: Aphididae).
Abstrak: Plant growth promoting rhizobacteria (PGPR) merupakan bakteri yang hidup dan berkembang disekitar perakaran tanaman yang dapat meningkatkan pertumbuhan tanaman dan sebagai agen antagonis. Penelitian ini bertujuan mengetahui pengaruh PGPR pada kacang panjang terhadap biologi dan statistik demografi A. craccivora Koch. Penelitian ini dilakukan di Laboratorium WiSH, Dramaga, Bogor dimulai dari bulan Oktober 2014 sampai Januari 2015. Penggunaan PGPR terdiri dari Rhizobium, Bacillus polymyxa, dan Pseudomonas fluorescens. Penggunaan PGPR berpengaruh terhadap biologi A. craccivora yaitu dapat memperpanjang stadia nimfa instar 2, siklus hidup, dan menurunkan keperidian. Penggunaan PGPR juga berpengaruh terhadap statistik demografi A. craccivora. Tanaman yang diaplikasikan PGPR mempunyai laju reproduksi kotor (GRR), laju reproduksi bersih (Ro), dan laju pertambahan intrinsik (r) A. craccivora yang lebih rendah daripada kontrol. PGPR dapat menghambat waktu berlipat ganda (DT) A. craccivora menjadi lebih lama daripada kontrol. PGPR dapat meningkatkan pertumbuhan tanaman, seperti adanya peningkatan panjang dan jumlah akar, jumlah bintil akar, tinggi tanaman, jumlah daun, panjang dan kerapatan trikoma.
Keyword: Aphis craccivora, biologi, kacang panjang, plant growth promoting rhizobacteria, statistik demografi

Judul: Pengaruh Plant Growth Promoting Rhizobacteria terhadap Biologi dan Statistik Demografi Aphis glycines Matsumura (Hemiptera: Aphididae) pada Tanaman Kedelai
Abstrak: On various plants, Plant Growth Promoting Rhizobacteria (PGPR) application known can suppress the development of plant pest population. This research aimed at PGPR effects against biology and statistic demographic of Aphis glycines Matsumura (Hemiptera: Aphididae) on soybean plant. This research conducted in the Department of Plant Protection, Faculty of Agriculture, Bogor Agricultural University. PGPR application, which consists of Bacillus polymyxa and Pseudomonas fluorescens can extend second instar nymphs stadia and life cycle of A. glycines. PGPR application also can effect to statistic demographic of Aphis glycines. The gross reproduction rate, net reproduction rate, and intrinsic growth rate of A. glicines on PGPR application plant is lower than non PGPR application plant. Moreover, PGPR application plant can extend long generation and doubling time of A. glycines. The use of PGPR can inhibits the development of A. glycines population on soybean plant.
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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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