Judul: Keberadaan Beberapa Virus dan Efisiensi Tular Benih Squash mosaic virus pada Cucurbitaceae
Abstrak: Virus-virus pada tanaman Cucurbitaceae dapat menyebabkan kegagalan panen dan kerugian ekonomi yang tinggi. Salah satu virus yang terdapat pada Cucurbitaceae dan terbawa benih adalah Squash mosaic virus. SqMV berbahaya karena dapat menyebabkan kerugian yang sangat tinggi dan menjadi penghambat bagi negara penanam Cucurbitaceae seperti Indonesia. Pengujian keberadaan Cucumber mosaic virus (CMV), Squash mosaic virus (SqMV), Watermelon mosaic virus-2 (WMV-2), Zucchini yellow mosaic virus (ZYMV), dan Tobacco ringspot virus (TRSV) pada sampel daun dan benih Cucurbitaceae dilakukan dengan menggunakan metode Indirect-ELISA. Pengujian bobot molekul virus dilakukan menggunakan metode Western blot. Benih Cucurbitaceae berasal dari distributor benih dan dari tanaman sakit. Sampel Cucurbitaceae hasil survei terinfeksi secara tunggal atau ganda oleh CMV, SqMV atau ZYMV. Benih Cucurbitaceae yang berasal dari distributor benih terinfeksi oleh SqMV dan ZYMV. SqMV ditemukan pada 13.3% benih oyong dan semangka, 33.3% benih zucchini, 73.3% benih kabocha, dan 100% benih mentimun dan melon. ZYMV hanya ditemukan pada benih oyong dan zucchini berturut-turut 13.3% dan 26.67%. SqMV ditemukan pada biji mentimun, oyong, dan melon yang berasal dari benih tanaman sakit berturut-turut pada 93.3%, 100%, dan 100% benih. Bobot molekul SqMV 45 kDa dan 69 kDa. SqMV telah berada di Jawa Barat. Oleh karena itu status SqMV sebagai OPTK A1 golongan 1 perlu ditinjau kembali.
Keyword: 

Judul: Efisiensi Penularan Cucumber mosaic virus, Zucchini yellow mosaic virus, dan Squash mosaic virus Melalui Benih Cucurbitacea
Abstrak: Seed-transmitted viruses have been known to cause negative effect on seed germination and seedling growth and may cause disease spread more widely in the field. Research was conducted to identify seed-transmitted viruses from Cucurbitaceae and to study their potential role as primary inoculum in the field. Cucurbitaceae seeds used in the experiment i.e. cucumber, bottle gourd, watermelon, zucchini, melon, and kabocha were obtained from commercial seeds available in the market. Evaluation of seed-transmitted viruses was done using growing on test method. I-ELISA and DIBA was used for detection of virus infection. Three viruses i.e. CMV, SqMV, and ZYMV were detected from cucumber field in Situgede, Dramaga, Bogor. CMV was detected from melon variety Kinanti and zucchini seed (2%) as well as from kabocha seed (12%). SqMV was detected 80%, 6%, and 2% from cucumber, melon variety Kinanti and bottle gourd seeds, respectively. Virus infection was detected in seedling up to 5 weeks after transplanting, i.e. CMV in kabocha and SqMV in cucumber. This results indicated the potential role of seed-transmitted viruses as primary inoculums in the field
Keyword: 

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.
Keyword: