Judul: Respon pertumbuhan padi terhadap pemberian bakteri fotosintetik anoksigenik
Abstrak: Padi pada sawah tergenang membentuk suatu lingkungan yang khas bagi mikroflora dan menjadi habitat sejumlah bakteri fotosintetik anoksigenik (BFA) yang dapat menghasilkan ALA ekstraseluler dan menambat nitrogen. Pada penelitian ini dipelajari respon pertumbuhan padi terhadap inokulasi BFA (sel hidup), pemberian metabolit ekstraseluler (supernatan) BFA, dan pemberian sonikasi sel BFA. Pemberian sel hidup BFA kepada tanaman padi memperlihatkan hasil yang lebih baik daripada pemberian supernatan BFA maupun sonikasi sel BFA. Inokulasi BFA memberikan hasil yang lebih baik diduga karena sel dapat menambat nitrogen dan ALA yang diproduksinya serta kemungkinan adanya hormon pertumbuhan. Dari hasil asai ALA yang dilakukan ternyata konsentrasi ALA yang ada masih terlalu rendah (5µM-15µM) untuk dapat memicu pertumbuhan padi. Berdasarkan hasil yang diperoleh dapat disimpulkan bahwa terdapat beberapa isolat BFA yang cenderung memicu pertumbuhan padi walaupun uji statistik masih tidak berbeda nyata dengan kontrol E. coli DH5a. Kemungkinannya karena kadar ALA yang dihasilkan rendah dan adanya perbedaan antara keadaan buatan di laboratorium dengan keadaan di alam dimana BFA berinteraksi dengan banyak jenis bakteri lain.
Keyword: Bakteri Fotosintetik

Judul: Pengaruh Pemakaian Bakteri Fotosintetik Anoksigenik terhadap Pertumbuhan Tanaman Padi
Abstrak: Nitrogen adalah salah satu unsur terpcnting bagi pertnmbuhan tanaman padi. Penambatan N2 dari udara merupakan peristiwa penting untuk mcningkatkan kadar nitrogen dalam tanah. Baktcri fotosintetik anoksigenik (BFA) memiliki kcmampuan menambal N2. Dalam penelitian ini dilakukan uji terhadap 15 isolat BFA dan kombinasinya dcngan Bacillus polymyxa dan Paenibacillus azotofixans, yang juga mampu mcnambat N1, atas pengaruhnya terhadap pertumbuhan tanaman padi yang dilihat dari berat keringnya. Data berat kering tanaman padi diolah dengan Rancangan Acak Lengkap dan Uji Duncan.
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Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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