Judul: Metode Binomial untuk Menentukan Harga Opsi Call Indonesia  dan Strategi Lindung Nilainya
Abstrak: Opsi merupakan suatu kontrak antara seorang pembeli dan seorang penjual yang memberikan hak kepada pembeli (tetapi bukan kewajiban) untuk menjual atau membeli sesuatu pada waktu tertentu pada tingkat harga tertentu yang disepakati pada saat ini. Suatu opsi untuk membeli sesuatu disebut call; sedangkan suatu opsi untuk menjual sesuatu disebut put. Seseorang yang menerbitkan suatu opsi disebut writer. Untuk memperoleh opsi, pemegang opsi membayar premi kepada writer. Opsi dapat dieksekusi sebelum waktu jatuh tempo (expiration date) yang disebut eksekusi lebih awal (early exercise). Opsi juga dapat dijual kapanpun sebelum jatuh tempo.
Keyword: Metode Binomial, Monte Carlo, opsi Indonesia, nilai opsi call, strategi hedging

Judul: Penentuan Harga Opsi Chooser dengan Menggunakan Metode Binomial.
Abstrak: Opsi chooser adalah opsi yang memberikan hak kepada pemilik opsi untuk memutuskan di beberapa titik dalam waktu sebelum jatuh tempo apakah menjadikan opsi tersebut sebagai opsi call atau opsi put. Karya ilmiah ini membahas tentang penentuan harga opsi chooser tipe Eropa menggunakan metode binomial dan menganalisis pengaruh beberapa parameter terhadap harga opsi chooser. Nilai hampiran opsi chooser dihitung menggunakan metode binomial, sedangkan nilai “eksak” didapatkan dari mengambil nilai hampiran dengan n (langkah) yang besar. Berdasarkan hasil penghitungan, pergerakan nilai opsi awalnya berfluktuasi kemudian nilai hampiran opsi chooser tipe Eropa semakin mendekati nilai “eksak” sehingga akan konvergen ke suatu nilai tertentu seiring bertambahnya langkah binomial.
Keyword: konvergen, metode binomial, opsi call, opsi chooser, opsi put

Judul: Heterologous Expression Of Endo-Β-Xylanase From Bacillus Pumilus Strain Bcrs-01 In Escherichia Coli.
Abstrak: Xylanases are glycoside hydrolase family 11 which depolymerise xylan in the plant cell wall, the most excessive form of hemicellulose. Endo-β-xylanases (EC 3.2.1.8) are most important to breakdown β-1,4-glicoside bond of xylan to produce disaccaride xyloolygosaccaride (XOs) and xylose (monomer). Bovine rumen fluids have potential to obtain endo-β-xylanase produced of bacteria. The objectives of this study were to obtain xylanase producing bacteria and to express xynA gene encoding endo-β-xylanase from bacterium in Escherichia coli. Twenty nine isolate bacteria have been succesfully isolated from bovine rumen fluid in agar medium containing birchwood xylan. Isolate BCRS-01 bacterium was previously screened for the high production of xylanase. Based on 16S rRNA gene sequence analysis, BCRS-01 showed high similarity (99%) to Bacillus pumilus (accession number NR043241). The crude xylanase had optimal activity at 55oC, pH 7.0. Furthermore, the crude xylanase exhibited broad pH stability from 4.0 to 10.0 and remained more than 60% and 40% of its activity after incubation at pH 4.0 until 10.0, respectively for 60 min. It also showed a stability at temperature 25-50oC since it retained 80% and 50% of its activity when incubated at 50oC or 30 and 60 min, respectively. The xylanase activity was strongly inhibited by Ca2+ and Cu2+ at concentration 10 mM, and as little as 1 mM for Mn2+. Therefore, this xylanase has potentially used as additive feeds in animal feed industry. The DNA sequence xynA gene encoded endo-β-xylanase was amplified and cloned into the expression vector pET-15by under the control of T7 promoter. The recombinant protein had succesfully expressed in Escherichia coli BL21 (DE3) pLysS. A protein recombinant of approximately, 26.7 kDa was observed on the SDS-PAGE analysis. Crude extract of recombinant endo-β-xylanase demonstrated activity of enzyme at 56 U mL-1 using birchwood xylan as a substrate at 55oC for 10 min.
Keyword: Bacillus pumilus, bovine rumen fluid, endo-β-xylanase, heterologous expression.