Judul: Pendugaan Kejadian Penyakit Tungro di Empat Kabupaten di Jawa Tengah Menggunakan Analisis Regresi Multivariat Berdasarkan Data Luas Tambah Serang, Luas Tambah Tanam Padi dan Curah Hujan Tahun 1995-2000
Abstrak: Tungro sebagai penyakit padi telah dikenal sejak lama di Indonesia, namun sebelum tahun 1 969 tungro tidak diperlimbangkan sebagai penyakit penting pada padi. Baru setelah penanaman monokultur varietas padi unggul yang rentan terhadap wereng hijau, yang merupakan vektor penyakit tungro maupun virus tungro, penyakit ini menjadi penting di Indonesia. Kejadian ledakan tungro di berbagai daerah di Asia Tenggara telah terjadi sejak tahun 1960. Dan berbagai kejadian ledakan tungro karakteristik serupa yang teramati adalah rendahnya kejadian penyakit tungro sebe1um dan sesudah ledakan. Karakteristik ledakan tungro yang tiba-tiba ini mengisyaratkan kebutuhan akan suatu model pendugaan yang memuat di dalamnya variabel-variabel lingkungan, tanaman inang, serta penyakit yang mampu memberi pendugaan akan te rjadinya ledakan secara dini. Suzuki mengajukan model pendugaan ledakan tungro dengan rnenggunakan data curah huj an berdasarkan kejadian ledakan tungro di Bali.
Keyword: 

Judul: Keragaman Gen Protein Selubung Isolat Rice tungro bacilliform tungrovirus (RTBV) dan Rice grassy stunt tenuivirus (RGSV) dari beberapa Kabupaten di Pulau Jawa, Keragaman Gen Protein Selubung Isolat Rice tungro bacilliform tungrovirus (RTBV) dan Rice grassy stunt tenuivirus (RGSV) dari beberapa Kabupaten di Pulau Jawa
Abstrak: Indonesia is the largest consumer of rice in the world. International Rice Research Institute (IRRI) estimated that Indonesia may require an increase in rice production for the next 25 years. Among many constrains in rice production increement is plant diseases including tungro and grassy stunt diseases. Tungro disease is caused by infection of two viruses, Rice tungro bacilliform tungrovirus (RTBV) and Rice tungro spherical waikavirus (RTSV). These viruses are transmitted by the rice leaf hopper vectors which mainly is green leafhoppers (Nephotettix virescens). RTBV is a determinant of the disease symptoms eventhough it could not infect rice without the presence of RTSV. Infected plants showed typical tungro symptoms involving stunting, yellow or orange-yellow discoloration of the leaves, reduced number of tillers and rust-colored spots on the leaves. In 2006 a new symptoms was found in paddy crop in Indonesia, i.e. yellow-orange discoloration of the leaves, reduced number of tillers without any reduction in plant height. It was reported that the disease is caused by infection of Rice grassy stunt tenuivirus (RGSV) the cause of grassy stunt disease. Symptoms similarity of tungro and RGSV infection may cause difficulty in disease diagnosis and cause confusion in determining diseases control strategies. Therefore research on symptoms and genetic diversity of RTBV and RGSV is necessary to determine the appropriate control strategy. The genetic diversity of RTBV isolates from South Asia and Southeast Asia as well as from some tungro endemic area in Indonesia based on the symptoms variation and diversity of coat protein gene have been reported. The genetic diversity of the isolates RGSV from two areas in Taiwan and Philippines based on symptoms variation have also been reported. Genetic and symptoms diversity of RTBV and RGSV could be analysed through the diversity of coat protein gene. Coat protein gene is known as a determinant factor of infection, virulence, and symptoms induction. The research is conducted to study the diversity of symptoms and coat protein gene of RTBV and RGSV from several districts in Java. The areas in Bogor, Subang, Pandeglang, Klaten, Batang, Sleman, Jember and Banyuwangi were selected as disease survey location because these regions were reported as endemic areas for tungro disease and brown leafhopper. The study includes three main activities, i.e. observation of symptoms in the field and sampling of infected plants, detection of RTBV and RGSV, and analysis of diversity of coat protein gene of RTBV and RGSV. Most infected plants in the fields showed tungro-like symptoms. Two variations of symptoms can be classified by the number of tillers and plant height. These symptoms variations can be caused by RTBV or RGSV infection or mix infection of RTBV and RGSV as indicated by detection results using PCR. Identification of total 64 samples showed infection of RTBV in 13 samples, RGSV in 36 samples and mix of RTBV and RGSV in 2 samples. The results showed that tungro-like symptoms were positive from infection of RGSV. Therefore identification of diseases based only on symptoms are not sufficient. The whole coat protein gene of RTBV was amplified using DA-F and DA-R primers with the amplicon
Keyword: 

Judul: Membran Komposit Kitosan-Natrium Alginat untuk Aplikasi Direct Methanol Fuel Cell
Abstrak: Composite of chitosan and sodium alginate can be utilized as base material of proton exchange membrane (PEM). The composite membranes were produced by various concentrations of chitosan-sodium alginate, namely 3:3, 3:4, 3:5, 3:6, 4:3, 5:3, and 6:3 (% b/v). The composites were characterized by using Fourier transform infrared spectrophotometer (FTIR), scanning electron microscope (SEM), and were tested for the performance as PEM from the proton conductivity obtained by using impedance spectrometer. The FTIR spectrum indicated the NH3C group at 1637.29 cm-1 and symmetrical COO group at 1253.68 cm-1 indicating interactions between chitosan and sodium alginate. SEM micrographs showed that the composite membrane was nonporous. Composite membrane with 3:5 chitosan-sodium alginate composition had the highest proton conductivity, namely 9.594 × 10-7 S/cm. Based on this research results, chitosan-sodium alginate composite membrane can be applied well in direct methanol fuel cell system.
Keyword: