Judul: Isolasi dan Seleksi Bacillus sp. untuk Biokontrol pada Tambak Udang
Abstrak: Penyakit bakteri yang umum ditemukan pada budidaya udang terutama disebabkan oleh Vibrio harveyi, selain itu syarat mutu dan keamanan pangan produk perikanan antara lain harus bebas dari cemaran mikrob seperti Escherichia coli. Tujuan penelitian ini untuk mengisolasi dan menyeleksi isolat bakteri Bacillus sp. dari tambak udang yang potensial digunakan sebagai agen biokontrol untuk menghambat V. harveyi dan E. coli di tambak udang. Bacillus sp. diisolasi dari sampel yang diambil dari tambak di provinsi Lampung. Sebanyak 175 isolat diperoleh dari 17 sampel berupa lumpur, air tambak dan saluran pencernaan udang. Dari 18 isolat yang yang memiliki aktifitas penghambatan, hanya delapan isolat yang memiliki indeks zona bening pada kedua bakteri indikator yaitu V. harveyi dan E. coli (perbandingan antara zona bening dan diameter koloni) yaitu sama dengan atau lebih dari 0.50. Tiga isolat yaitu LTS36, LTS40 dan LTW54 menunjukkan aktivitas antimikrob paling stabil saat diuji terhadap bakteri indikator dengan metode lapis ganda.
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Judul: Karakterisasi Fisiologi dan Identifikasi Molekuler Isolat-isolat  Bacillus sp. Penghasil Bakteriosin Asal Tambak Udang
Abstrak: Vibriosis merupakan kendala utama dalam pengembangan budidaya tambak udang. Penggunaan probiotik dari genus Bacillus sebagai agen biokontrol dapat dijadikan cara penanggulangan penyakit vibriosis. Isolat-isolat Bacillus sp. indigenus yang diisolasi dari tambak udang seperti isolat LTC8, LTC13, LTW4, LTW54, LTS36, dan LTS40 diketahui dapat menghambat pertumbuhan Vibrio harveyi, Escherichia coli, dan Staphylococcus aureus. Dalam penelitian ini dilakukan verifikasi daya hambat, uji fisiologi secara manual maupun menggunakan MicrogenTM GN-ID A+B Panel dan analisis sekuen gen 16S rRNA dari keenam isolat tersebut. Isolat LTS40, LTW54, dan LTC13 memiliki indeks penghambatan (IP) terbesar terhadap V. harveyi. IP terbesar terhadap E. coli dan S. aureus ditunjukkan oleh isolat LTW54 dan LTC13. Keenam isolat Bacillus menunjukkan hasil positif terhadap uji nitrat, Voges Proskauer (VP), pati, glukosa (kecuali LTS40), sukrosa (kecuali LTC13), O-nitrophenyl-â-D-galaktopiranosa (ONPG) (kecuali LTW4), dan gelatin (kecuali LTW54). Analisis 16S rRNA menunjukkan isolat LTW4, LTC13, LTS40, dan LTW54 memiliki kemiripan 98-99% dengan Bacillus subtilis sedangkan isolat LTS36 dan LTC8 memiliki kemiripan 98-99% dengan Bacillus sp. Pohon filogenetik menunjukkan keenam isolat berada dalam satu kelompok dan berkerabat dengan B. subtilis galur 168.
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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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