Judul: Kajian Paleoklimatologi dan Perubahan Suhu Global
Abstrak: Global climate change is a change of climate patterns and intensity on a global scale as a result of changes in the energy budget components within the earth system and may be caused by both natural and antrophogenic factors. Studies of climate change requires a long data which may be reconstructed by several methods of paleoclimatology including ice cores, tree ring, coral, and pollen methods. Climate reconstruction using Ice core method requires longer data records compared with the tree ring, coral, and pollen method. The complexity of physical and chemical analysis are major constaints in utilizing ice core and coral method. On the other hand, the unven speard of tree on the earth cause limitations to the information obtained from tree ring and pollen method. Among factors consider important to the global climate change include solar constant, properties of earth surface, and atmospheric chemical compositions of greenhouse gases. Radiative forcing is an index defined by the rate of energy change per unit area of the globe as measured at the top of the atmosphere. Global climate change is indicated by increased of global average surface temperature which according to data records has increased by 0.7oC during the last century. A number of literature suggest the temperature rise was due to anthropogenic factors; however, using simplified energy balance model of the earth-atmosphere system reveals that an increase of solar constant by 1% (which may occur during the last century), while holding other factors unchanged, will result in an average global surface temperature increase of 0.6oC which is fairly close to the value obtained from observations. It must be emphasized that climate is an extremely complex system in which various factors interact with each other in some forms of linear and non-linear feedbacks. Analysis of time series data of Jakarta Observatory which cover a period of 1965-2010 shows a slight increase of average temperature and decrease of average rainfall.
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Judul: Analisis Peningkatan Intensitas Cuaca Ekstrim Di JABOTA (Jakarta, Bogor, Tangerang) Periode 1980 - 2008
Abstrak: Pertumbuhan penduduk mempengaruhi perubahan penggunaan lahan terutama berkurang ruang terbuka hijau. Hal ini mempengaruhi naiknya suhu udara dan meningkatnya cuaca ekstrim. Penelitian di beberapa negara sudah terbukti adanya kenaikan suhu dan cuaca ekstrim sebagai akibat dari perubahan penggunaan lahan seperti Taiwan, Cina dan Jepang. Data yang di gunakan pengamatan cuaca harian stasiun Meteorologi sekitar Jabota kurun waktu antara tahun 1980-2008 dibagi menjadi dua periode (periode 1980-1997 dan 1998- 2008) dan dibandingkan untuk mengetahui peningkatan suhu dan cuaca ekstrim. Data pengamatan udara atas periode tahun 1988-2008 dibagi menjadi dua periode dan dibandingkan untuk mengetahui peningkatan suhu udara atas pada lapisan tertentu. Data cuaca setiap jam antara tahun 2003-2008, stasiun Curug sebagai contoh untuk menganalisis pergeseran waktu kejadian suhu maksimum dan waktu terjadinya badai petir. Hasil analisis menunjukkan adanya peningkatan suhu rata-rata pada periode kedua, meningkatnya frekuensi suhu di atas 34°C, meningkatnya frekuensi curah hujan ekstrim pada bulanbulan tertentu terutama pada bulan di musim hujan dan transisi, meningkatnya frekuensi kejadian badai petir, meningkatnya rata-rata suhu udara atas terutama pada lapisan permukaan hingga 500mb, terjadi pergeseran waktu suhu maksimum pada bulan-bulan tertentu di musim kemarau dan transisi pada dari pukul 13.00 mejadi pukul 14.00 wib dan waktu kejadian badai petir tertinggi antara pukul 15.00-17.00 wib dan pukul 19.00-20.00 wib
Keyword: land us e changes, increase temperature, extreme weather

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.