Judul: Efikasi Beberapa Ekstrak Tanaman untuk Mengendalikan Bean common mosaic virus pada Kacang Panjang di Lapangan
Abstrak: Kacang panjang merupakan sayuran penting di Indonesia. Salah satu faktor pembatas produksi kacang panjang adalah adanya infeksi Bean common mosaic virus (BCMV). Di lapangan, infeksi BCMV sulit untuk dikendalikan. Salah satu upaya pengendalian virus tanaman adalah dengan memanfaatkan ekstrak tanaman yang mengandung substansi antivirus. Penelitian ini bertujuan untuk mengetahui keefektifan beberapa ekstrak tanaman yang diduga memiliki substansi antivirus untuk mengendalikan BCMV pada kacang panjang di lapangan. Empat belas ekstrak tanaman terpilih diaplikasikan dalam bentuk ekstrak kasar dan ekstrak protein yang disemprotkan ke daun satu jam sebelum inokulasi mekanis BCMV. Percobaan dirancang dengan RAK dan tiap perlakuan terdiri dari 3 blok sebagai ulangan. Peubah yang diamati adalah waktu inkubasi, kejadian penyakit, gejala, keparahan penyakit dan titer BCMV yang dideteksi secara serologi. Hasil penelitian menunjukkan bahwa baik perlakuan ekstrak kasar maupun protein memperpanjang waktu inkubasi dan menekan keparahan penyakit. Tingkat hambatan relatif keparahan dan titer BCMV perlakuan ekstrak kasar berturut-turut sebesar 48,4% - 89.8% dan 59.8% - 99.1%, sedangkan pada perlakuan ekstrak protein berturut-turut sebesar 43.2% - 74.4% dan -55.1% - 42.7%. Perlakuan ekstrak kasar menunjukkan lebih efektif dalam menekan BCMV dibandingkan perlakuan ekstrak protein. Diantara ekstrak kasar yang diuji, ekstrak bogenvil dan jambu biji menunjukkan penekanan BCMV tertinggi di lapangan
Keyword: antivirus, BCMV, plant extract, yard long bean

Judul: Seleksi Substansi Antivirus Asal Tanaman dan Efikasinya dalam Mengendalikan Bean common mosaic virus Strain Black eye cowpea (BCMV-BlC) pada Kacang Panjang.
Abstrak: Bean common mosaic virus (BCMV) is an important virus on yard long bean and it is difficult to control. Control efforts by utilizing antiviral substances of plant origin is worthy to studied. The research was done to select and test the effectiveness of plant extracts in suppressing BCMV infection on yard long bean. Twenty two plant extracts were selected by (1) spraying the crude extract to Chenopodium amaranticolor leaves, then plant inoculated by BCMV 1 hour after spraying, and (2) mixturing the crude extract with sap containing BCMV, then inoculated mechanically to C. amaranticolor. Lesio local number and lesio local inhibition percentage are measured. All plant extract treatments were able to reduced lesio local formation significantly in compare to untreatment control. Further, extracts treatment showing highest lesio local inhibition are selected to test the efectiveness in supressing BCMV infecting yard long bean in green house trial. Fifthteen plant extracts which may containing antiviral substances and inducing plant systemic resistance on yard long bean showed that except geranium and red ginger extracts, other plant extract treatments were able to reduced disease incidence and severity, milder symptom, and decreased BCMV titer, respectively. Among tested plant extracts, the most effective in suppressing BCMV infection are Bougainvillea spectabilis , Mirabilis jalapa, and Celosia cristata.
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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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