Judul: Deteksi Pepper vein yellow virus (PeVYV) Penyebab Penyakit Daun Merah pada Tanaman Wortel di Jawa Barat
Abstrak: Red leaf disease (RLD) is a new reported virus disease on carrot in Indonesia. The disease was characterized by reddening of leaves without any retardation of plant development. The disease was resemble to „carrot motley dwarf (CMD)‟ reported worldwide. Although the symptom likely to be similar, these two diseases were caused by two different viruses. CMD was caused by infection of Carrot red leaf virus (Polerovirus). Whereas, RLD was induced by other Polerovirus, Pepper vein yellow virus (PeVYV). PeVYV has a narrow host range, limited on chili pepper. A report that PeVYV infect carrot in a field of Cipanas, Cianjur was the first report for the virus having host plant other than chili pepper. In this study, some surveys were conducted to elucidate the occurrence of PeVYV in carrot production centers of West Java. Some carrot plants showing RLD were collected from Cipanas (Cianjur), Lembang (West Bandung), and Cikajang (Garut). Based on reverse trancription-polymerase chain reaction analyses, it was found that PeVYV has been already occurred in the areas. The fact that all samples from Garut were infected by the virus suggest that PeVYV may first infected carrot plants in Garut, then spread to other areas of West Java. This is the first report concerning the distribution of PeVYV on carrot crops in West Java.
Keyword: RT-PCR., Production centres, Polerovirus, Distribution

Judul: Identifikasi Spesies Polerovirus pada Tanaman Wortel melalui Analisis Sekuen Nukleotida Gen Coat Protein
Abstrak: During survey on central production of carrot in West Java, some plants were found exhibiting virus-like induced symptoms. The diseased plants showed reddening and yellowing of leaves, but the plants were unlikely to be stunting. The symptom was resemble to the disease reported in other countries as „motley dwarf‟, in which the reddening, yellowing, and stunting is accentuated. The disease was reported to be caused by mixed infection of two different viruses that were Carrot red leaf virus (CtRLV), member of genus Polerovirus and Carrot mottle mimic virus (CMoMV), member of genus Umbravirus. To know the causal agent of the disease present in Indonesia, total RNA extraced from the symptom exhibiting carrot plants obtained from field in Cipanas, Cianjur, West Java was subjected to reverse transcription-polymerase chain reaction (RT-PCR) using primer pair specific to CtRLV. Unfortunately, the virus was failed to be detected and therefore, further identification was focused on other virus. Using primer pair of CP-F (5‟-AATTAAGGATCCAATACGGGAGGGGTTAGGAGAAAT-3‟) and CP-R (5‟-AATTAACTGCAGTTTCGGGTTGTGCAATTGCACAGTA-3‟), that were specific to Polerovirus. RT-PCR was successfully amplified a DNA band of about 650 bp, the size which accordance with the designed primers. The RT-PCR product was then sequenced and the 630 nucleotides were succesfully read. The BLAST analysis of the nucleotide sequence revealed that the virus associated with red leaf disease on carrot in West Java was associated with Pepper vein yellow virus (PeVYV). PeVYV was a virus found previously infected chilli pepper in Bali. This is the first report concerning PeVYV infected carrot in Indonesia.
Keyword: reverse transcriptionpolymerase chain reaction, red leaf disease, Pepper vein yellow virus

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: