Judul: Aktivitas Antibakteri Zat Ekstraktif Kayu Balata (Manilkara bidentata) Terhadap Bakteri Pseudomonas aeruginosa dan Staphylococcus aureus
Abstrak: Penelitian ini bertujuan menentukan kadar zat ekstraktif kayu balata (Manilkara bidentata), menguji aktivitas antibakterinya terhadap Pseudomonas aeruginosa dan Staphylococcus aureus, serta mengidentifikasi komponen kimia fraksi teraktif dari zat ekstraktif kayu balata. Ekstraksi serbuk kayu menggunakan metode maserasi dengan pelarut aseton. Ekstrak aseton kayu balata difraksinasi secara bertingkat menggunakan pelarut n-heksana, dietil eter, dan etil asetat. Pengujian aktivitas antibakteri menggunakan metode difusi cakram dengan pemberian konsentrasi 10%, 20%, 30%, dan 50% pada tiap fraksi. Identifikasi senyawa kimia zat ekstraktif menggunakan GC-MS. Hasil penelitian menunjukkan kadar ekstrak aseton kayu balata sebesar 3,01%. Hasil fraksinasi ekstrak aseton menghasilkan fraksi n-heksana, dietil eter, etil asetat dan residu berturut-turut 0,27%, 0,26%, 0,45%, dan 2,03%. Fraksi teraktif dan terefektif menghambat pertumbuhan bakteri P. aeruginosa dan S. aureus adalah fraksi dietil eter. Pemberian fraksi dietil eter pada konsentrasi 20% menunjukkan aktivitas antibakteri S. aureus dan P. aeruginosa yang tergolong kuat dan sedang, sedangkan fraksi etil asetat, n-heksana, residu tergolong rendah. Fraksi dietil eter mampu menghambat S.aureus lebih kuat dibanding P.aeruginosa. Efektivitas antibakteri pada P.aeruginosa lebih tinggi dibandingkan S.aureus. Hasil analisis GC-MS menunjukkan 10 senyawa yang mendominasi yaitu Dietilheksil ftalat, Asam Benzoat, Asam Adipat, Asam Siringat, Stigmasta-7,16-dien-3-ol, Asam Barbiturat, Propilamina, Asam Isovanilat, Diaseton alkohol, dan 5-Chloroindole.
Keyword: antibakteri, Manilkara bidentata, Pseudomonas aeruginosa, Staphylococcus aureus

Judul: Aktivitas Anti-Rayap Zat Ekstraktif Kayu Balata (Manilkara bidentata) terhadap Rayap Tanah Coptotermes curvignathus Holmgren.
Abstrak: Kayu balata (Manilkara bidentata) berasal dari famili dan genus yang telah diketahui menghasilkan berbagai senyawa dengan bioaktivitas tinggi. Penelitian ini bertujuan menentukan kadar ekstraktif kayu balata, menguji aktivitas anti-rayap ekstrak terhadap rayap Coptotermes curvignathus, dan mengidentifikasi senyawa kimia yang diduga paling berpengaruh dalam ekstrak. Serbuk kayu dimaserasi menggunakan pelarut aseton kemudian difraksinasi hingga didapatkan fraksi n-heksan, etil eter, etil asetat, dan residu. Setiap fraksi diumpankan ke rayap melalui kertas selulosa pada konsentrasi 2, 4, 6, 8, dan 10%. Identifikasi senyawa dilakukan dengan analisis GC-MS. Hasil penelitian menunjukkan kadar ekstraktif kayu balata sebesar 3.01%. Fraksi etil asetat menghasilkan aktivitas anti-rayap tertinggi yang pada konsentrasi 10% menghasilkan nilai mortalitas rayap sebesar 84% dan kehilangan berat kertas sebesar 23.2 %. Asetaldehid dan salicylic acid diduga merupakan senyawa yang paling berpengaruh terhadap aktivitas anti-rayap.
Keyword: zat ekstraktif, Manilkara bidentata, Coptotermes curvignathus, asetaldehid, salicylic acid

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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