Judul: Penerapan Analisis Konjoin Terhadap Preferensi Penggunaan Instant Messenger
Abstrak: Pesan singkat (instant messenger) merupakan salah satu aplikasi yang tersedia pada smartphone yang digunakan untuk berkomunikasi. Terdapat beberapa jenis instant messenger dan fitur yang mendukung penggunanya. Penelitian ini membahas tentang preferensi penggunaan instant messenger di kalangan mahasiswa dengan analisis konjoin. Metode yang digunakan adalah traditional conjoint dengan data numerik berupa rating. Hasil analisis konjoin menunjukkan bahwa atribut yang paling dipentingkan responden adalah chat tambahan dengan rata-rata nilai penting relatif (NPR) sebesar 27.91%, hal ini berarti sebagian besar responden mengutamakan penggunaan instant messenger sebagai alat komunikasi yang lebih cepat dan mudah. Atribut kedua yang dipentingkan adalah atribut akses komputer dengan rata-rata NPR sebesar 19.53%. Atribut fitur tambahan merupakan atribut yang paling tidak dipentingkan dengan rata-rata NPR sebesar 11.02%. Kombinasi level dari atribut yang paling disukai responden adalah chat tambahan berupa panggilan suara dan video, kapasitas grup obrolan kurang dari 150 kontak, jumlah karakter pesan kurang dari 2000 karakter, dapat diakses melalui komputer, memiliki fitur tambahan stiker dan emoticon, serta dapat mengirim berkas berupa foto dan video.
Keyword: analisis konjoin, instant messenger, NPR, preferensi, rating

Judul: Pendekatan Metode Konjoin untuk Menentukan Preferensi Atribut Telepon Seluler Pintar pada Mahasiswa FMIPA IPB Angkatan 2009-2011
Abstrak: Nowadays the development of smart phones advanced rapidly. This forced producers to create products that are most desirable for all kind of consumers, including teenagers and youngsters. In this connection, information about students preferences on the smart phone attributes is very important for the producers. Conjoint method is a statistical tools that can be used to identify smart phone attributes that are most preferred by students. This research used students of FACULTY OF MATHEMATICS AND NATURAL SCIENCES of entering years, 2009-2011 as respondents. There were 16 stimuli combinations that were used in this research. Two assessment methods were used: ranking and rating methods. The attributes most preferred were price, design and added features consecutively. For ranking method, repondents choose price as the most preferred, while for rating method the most desired attribute was design.
Keyword: conjoint analysis, smart phone

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.