Judul: Deteksi dan Identifikasi Virus dan Tungau pada Bibit Bawang Merah Impor dan Lokal
Abstrak: Every year, Indonesia imports large amount of shallots from several countries. This hight importation may increase the risk of entrance of quarantine pests and diseases. Laboratory study was conducted in order to detect and identify viruses and mites associating import and local shallots. Observations were conducted using shallots imported from Thailand, Philippines, and China; whereas for local varieties, observations were done using several varieties of shallots (varieties Jawa, Biru, Nganjuk, Brebes and Tuk Tuk) collected from farmers in Bantul Districs Yogyakarta. Based on RT-PCR and sequencing of the nucleotide, no viruses were found on imported shallots, but Shallot yellow stripe virus (SYSV) was found from local varieties Jawa and Brebes, with diseases incidence of 60% and 53.3% respectively. Morphological-based identification found 12 genus of 11 families of non quarantine pest mites were found on import and local shallots. The most frequent species found were Caloglyphus berlesei, Cheyletus mallacensis, Proctolaelaps sp and Leiodynichus sp.
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Judul: Deteksi Virus Yang Menginfeksi Allium dan Beberapa Tanaman Hias Herba
Abstrak: Kelompok Allium (bawang putih, bawang merah, bawang bombai, bawang daun) dan tanaman hias herba merupakan komoditas hortikultura yang penting secara ekonomi dalam perdagangan internasional. Perdagangan komoditas ini sering kali dilakukan melalui umbi yang memiliki potensi besar terhadap munculnya penyakit baru di suatu negara, termasuk Indonesia. Potyvirus dan Carlavirus dilaporkan sebagai virus utama yang menginfeksi bawang. Tujuan dari penelitian ini adalah mendeteksi dan mengidentifikasi Carlavirus dan Potyvirus yang menginfeksi bawang dan tanaman hias herba yang berasal dari sampel lapangan dan umbi impor. Sampel bawang merah,bawang daun, dan tanaman hias herba diambil secara purposive sampling di beberapa lokasi. Sampel bawang putih merupakan umbi impor yang diperoleh dari Balai Besar Karantina Hewan, Ikan, dan Tumbuhan DKI Jakarta dan ditumbuhkan di laboratorium. Deteksi virus dilakukan dengan metode one-step reverse transcription polymerase chain reaction (RT-PCR) menggunakan primer universal, yaitu AlcarF/Poty1 untuk Carlavirus dan U341/Poty1 untuk Potyvirus. Hasil deteksi menunjukkan bahwa Carlavirus yaitu Shallot latent virus (SLV) ditemukan pada bawang merah, bawang putih, dan bawang daun serta Nerine latent virus (NeLV) pada Hippeastrum sp dan Hymenocallis speciosa. Onion yellow dwarf virus (OYDV), Shallot yellow stripe virus (SYSV), dan Amazon lily mosaic virus (ALiMV) anggota Potyvirus yang masing-masing ditemukan pada bawang merah, bawang putih, dan Hippeastrum sp. Deteksi NeLV dan ALiMV yang menginfeksi tanaman hias pada studi ini merupakan laporan pertama di Indonesia. Hasil dari penelitian ini dapat menjadi basis data bagi Badan Karantina Indonesia dalam melakukan upaya pencegahan masuk dan tersebarnya Organisme Pengganggu Tumbuhan Karantina., Alliums (garlic, onion, shallot) and herbaceous ornamental plants are economically important horticultural commodities in international trade. The trade of these commodities often through vegetative propagation that has big potential on new emerging diseases in a country, including Indonesia. Potyvirus and carlavirus are reported as the main viruses infecting allium. This research aims to detect and identify Carlavirus and Potyvirus infecting alliums and herbaceous ornamental plants. Garlic bulb samples were obtained from Indonesian Plant Quarantine Agency (BBKHIT DKI Jakarta) which were then grown in the laboratory. Samples of shallots, leeks, and ornamental plants were taken purposively in several locations. Virus detection was done by one step reverse transcription polymerase chain reaction (RT-PCR) method using universal primers, namely AlcarF/Poty1 for Carlavirus and U341/Poty1 for Potyvirus. Detection results showed that Carlavirus those are Shallot latent virus (SLV) was found in shallot, garlic, and leek, and Nerine latent virus (NeLV) in Hippeastrum sp. and Hymenocallis speciosa. Onion yellow dwarf virus (OYDV), Shallot yellow stripe virus (SYSV) and Amazon lily mosaic virus (ALiMV) are members of Potyvirus each found in shallot, garlic and Hippeastrum sp. The results of this study can be a basis data for Indonesian Plant Quarantine Agency to prevent the new emerging disease. For our knowledge, this is the first report of NeLV and AliMV infecting ornamental plants in Indonesia.
Keyword: ALiMV, Carlavirus, NeLV, Potyvirus, primer universal, Amaryllidaceae

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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