Judul: Penapisan Aktivitas Antibakteri Ekstrak Metanol Sianobakteria Terhadap Micrococcus luteus dan Escherichia coli
Abstrak: Sianobakteria adalah mikroalga yang mempunyai ciri seperti bakteri Gram negatif. Namun sianobakteria memiliki klorofil sehingga dapat melakukan fotosintesis. Sianobakteria memiliki bioaktifitas yang dapat berfungsi sebagai antibakteri. Penelitian ini bertujuan menguji strain sianobakteria yang mempunyai aktivitas senyawa antibakteri dengan metode mikrodilusi. Sianobakteria yang didapat berdasarkan karakteristik morfologi adalah ordo Oscillatoriales dan Chroococcales. Ekstrak sianobakteria yang dibuat dengan menggunakan pelarut metanol dapat menghambat pertumbuhan bakteri Gram positif dan Gram negatif. Ekstrak metanol sianobakteria dengan kode isolat LIPI-F-069 dan LIPI-F-077 memiliki aktivitas antibakteri paling besar dalam menghambat pertumbuhan bakteri Micrococcus luteus dan Escherichia coli. Pada konsentrasi 0.02 mg/mL, ekstrak dari isolat LIPI-F-069 memiliki nilai penghambatan sebesar 80.43% terhadap Micrococcus luteus dan 96.16% terhadap Escherichia coli, daya hambat untuk Lipi-F-077 sebesar 79.51% terhadap Micrococcus luteus dan sebesar 95.61% terhadap Escherichia coli.
Keyword: aktivitas antibakteri, kultivasi, morfologi, sianobakteria

Judul: Penapisan Aktifitas Antibakteri Ekstrak Etil Asetat Sianobakteri
Abstrak: Penelitian ini bertujuan mencari isolat sianobakteri yang memiliki aktifitas ekstrak paling baik dalam menghambat pertumbuhan Escerichia coli dan Micrococcus luteus secara in vitro. Etil asetat digunakan sebagai pelarut untuk ekstraksi biomassa sianobakteri. Dua puluh empat ekstrak etil asetat sianobakteri dapat menghambat pertumbuhan bakteri. Ekstrak dari isolat Lipi-F-001 dan Lipi-F-005 secara konsisten memiliki % daya hambat paling baik terhadap E.coli dan M.luteus. Pada konsentrasi 0.02 mg/mL, ekstrak dari isolat Lipi-F-001 memiliki % daya hambat sebesar 98.89% terhadap E.coli dan 59.33% terhadap M.luteus, dan % daya hambat untuk Lipi-F-005 sebesar 63.05 % terhadap E.coli dan terhadap 27.00 % M.luteus . Isolat Lipi-F-001 diduga merupakan Arthronema sp dan Isolat Lipi-F-005 diduga merupakan Leptolyngbya sp.
Keyword: Antibakteri, sianobakteri, Arthronema sp., Leptolyngbya sp.

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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