Judul: Evaluasi Produktivitas Beberapa Varietas Padi
Abstrak: The research was conducted during February to June 2014 in Muara Rice Research Institute, Bogor. The purpose of this study was to determine the factors that affect the productivity of some rices varieties The design used was a randomized complete design group with one factor consists of 6 varieties. The varieties used were high yielding varieties (Inpari 13, Ciherang, Mekongga), a new plant type of rice (IPB 4S), local variety (Mentik Wangi), and hybrid variety (Hipa Jatim 2). Each variety was replicated of three. The results showed that in general, high yielding varieties (VUB) Inpari 13, Ciherang and Mekongga have higher productivity than other varieties (local, PTB, hybrid). VUB Productivity ranged from 4.59 to 5.62 tons per hectare. The results of the three VUB productivity was influenced by yield components such as number of productive tillers, 1000 grain weight, percentage of filled grain and resistance to pests and diseases.
Keyword: Bogor Agricultural University (IPB), productivity, yield component, rice varieties

Judul: Keragaan Agronomi Varietas Padi di Kabupaten Bogor dan Kabupaten Subang Menggunakan Sistem Tanam Jajar Legowo 4:1
Abstrak: Peningkatan produksi padi dapat dilakukan dengan penggunaan varietas unggul didukung oleh sistem budidaya yang tepat dan lingkungan yang sesuai. Lokasi atau lingkungan tumbuh yang berbeda memiliki perbedaan kondisi agroekosistem sehingga dapat menyebabkan pertumbuhan dan produksi yang berbeda pada varietas yang dibudidayakan. Penelitian ini bertujuan mengetahui pengaruh lokasi terhadap keragaan agronomi dan produktivitas beberapa varietas padi yang ditanam menggunakan sistem tanam jajar legowo 4:1. Varietas yang digunakan yaitu Inpari 32, Inpari 33, Inpari 43, IPB 3S, IPB 9G, dan Batang Piaman. Rancangan yang digunakan adalah Rancangan Kelompok Lengkap Teracak (RKLT) dengan satu faktor varietas, kemudian dilakukan analisis gabungan antar lokasi percobaan. Lokasi tanam berpengaruh terhadap jumlah anakan, jumlah malai per rumpun, jumlah gabah total per malai, jumlah gabah bernas total per malai, dan bobot gabah kering giling (GKG). Varietas unggul baru (VUB) yang meliputi Inpari 32, Inpari 33, dan Inpari 43 memiliki ciri-ciri jumlah anakan banyak dengan jumlah gabah per malai kategori sedikit dan sedang, sedangkan padi tipe baru (PTB) memiliki ciri-ciri jumlah anakan sedikit dengan jumlah gabah per malai kategori sedang. Jumlah anakan, jumlah malai per rumpun, dan jumlah gabah per malai akan berpengaruh pada produksi padi., The effort for Increasing rice production could be achieved by planting high yielding varieties supported by implementing an appropriate cultivation system and suitable growing environments. Differetnt location or growing environment have different agroecosystem conditions could be differences growth and production of cultivated varieties. This study aimed to determine the effect of different location on agronomic performance and productivity of several rice varieties grown using “jajar legowo 4:1” system. The varieties used were Inpari 32, Inpari 33, Inpari 43, IPB 3S, IPB 9G, and Batang Piaman. It was arranged in Randomized Complete Block Design (RCBD) of one factor, namely variety, then a combined analysis was carried out between the experimental locations. Planting location affected the total stem, total panicle per clump, total grain per panicle, total pithy grain per panicle, and dry milled grain weight (GKG). The new superior varieties (VUB) which include Inpari 32, Inpari 33, and Inpari 43 have the characteristics of a large number of tillers with the number of grain per panicle in the category of few and medium, while the new type of rice (PTB) has the characteristics of a small number of tillers with the number of grain per panicle medium category. The number of tillers, number of panicles per clump, and number of grain per panicle will affect rice production.
Keyword: Agroecosystem, high yielding varieties, productivity

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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