Judul: Resistensi beras terhadap serangan sitophilus oryzae linnaeus (coleoptera, curculionidae)
Abstrak: Sitophilus oryzae Linnaeus merupakan salah satu hama gudang yang termasuk penting, karena menimbulkan kerusakan besar terhadap bahan makanan terutama beras dan jagung yang disimpan. Di negara-negara maju kerusakan tersebut mencapai 5-10 persen per tahun, dan di negara-negara berkembang 10-54 persen per tahun. Cara yang umum untuk mengatasi hama gudang adalah dengan fumigasi insektisida. Akan tetapi karena senyawa kimia tersebut dapat mencemari bahan makanan dan lingkungan, maka cara tersebut memerlukan pertimbangan yang seksama. Kecuali itu penekanan populasi ini menghendaki cara yang praktis, ekonomis dan tidak membahayakan manusia. Salah satu kemungkinan yaitu dengan memanfaatkan resistensi yang mungkin ada pada beras terhadap serangan S.oryzae. Tujuan penelitian: (1) Mempelajari kemungkinan adanya varietas beras yang tidak disukai oleh serangga S.oryzae. (2) Mempelajari kemungkinan adanya varietas beras yang dapat berpengaruh buruk terhadap kehidupan S. oryzae. Penelitian terdiri dari : (1) Penelitian preferensi, dan (2) Penelitian antibiosis. Penelitian preferensi dilakukan dengan rancangan kelompok dalam enam ulangan. Penelitian antibiosis dilakukan dengan rancangan acak lengkap dalam tiga, enam dan 12 ulangan.
Keyword: Oryza;, Cereals;, Crops plants;, Plant diseases;, Bogor Agricultural University;

Judul: Resistensi Relatif Beras Pecah Kulit dan Beras Sosoh Lima Varietas Padi asal Banyumas terhadap Serangan Sitophilus oryzae
Abstrak: The purpose of this study was to examine the resistance level of five different variety of brown rice and milled rice from Sitophilus oryzae attack during storage. Five varieties of rice that examined were Pandanwangi, Inpari 13, IR-64, Situ Bagendit, and Srikandi which all were planted in Banyumas region. This research was conducted in two experiments. The first experiment is done to measure the growth of Sitophilus oryzae during storage, while the second experiment is done to measure the rate of loss during storage. In the first experiment, 200 seeds of rice was infested by 5 couples of Sitophilus oryzae aged 7-15 days and kept for 7 days. The insects were then removed and the rice was observed every day for 14 days for emergence of the first generation (F1) of insects. The progenies were counted every day until there were no emergence for five consecutive days. The experiments were conducted in three replications. From this experiment, the parameters were number of progenies (Nt), development period (D), development index (ID), intrinsic rate of increase (Rm), and weekly multiplication capacity (λ). In second experiment, 100 g of rice infested by 25 insects and stored for 6 weeks. After 6 weeks, insects were removed and the storage loss were determined. In this second experiment, the parameters observed were percentage increase of water fraction, the loss of dry matter loss, and percentage of frass. Those two experiments were conducted in three replication. According to this experiment, Srikandi rice has the highest resistance towards Sitophilus oryzae attack among other varieties.
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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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