Judul: Maskulinisasi Ikan Cupang (Betta splendens) Melalui Perendaman Embrio dalam Ekstrak Purwoceng (Pimpinella alpina)
Abstrak: This study aimed to know the effect of extract of P. alpina for masculinization of Betta splendens. This research used the Completely Randomized Design with 3 treatments that were distinguished by doses of extract of P. alpina, those are 10, 20, and 30 μL/L, and 0 μL/L as control. The treatments are given to 35 embryos by immersion in extract of Pimpinella alpina when eye spots phase or about 28th hour after fertilization. The immersion process was done for 8 hours. The result showed that 20 μL/L dose of P. alpina’s extract produced male fish percentage 62,66%, it’s higher than control (45,91%), and hatching rate was 85,71%. At the higher dose (30 μL/L), male fish population and hatching rate went down with each value 39,72% and 68,57%.
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Judul: Maskulinisasi Ikan Cupang Betta splendens dengan Ekstrak Tanaman Purwoceng Pimpinella alpina Melalui Perendaman Artemia
Abstrak: Ikan cupang Betta splendens jantan memiliki keindahan warna serta sifat yang agresif sehingga banyak diminati dan memiliki harga jual yang lebih tinggi. Penelitian ini dilakukan untuk menguji penggunaan ekstrak tanaman purwoceng dengan teknik perendaman artemia pada maskulinisasi ikan cupang. Penelitian ini menggunakan rancangan acak lengkap dengan tiga perlakuan dosis ekstrak tanaman purwoceng (20, 40, dan 60 mg/L), perlakuan 17α-methyltestosterone (MT) 500 μg/L dan kontrol dengan masing-masing tiga ulangan setiap perlakuan. Artemia bervolume 100 mL diperkaya selama 24 jam melalui perendaman dan diberikan pada larva sejak berumur 4 hari setelah penetasan hingga 40 hari. Jenis kelamin ikan yang telah berumur 2 bulan diidentifikasi. Hasil penelitian menunjukkan bahwa perlakuan ekstrak tanaman purwoceng 20 mg/L memberikan nisbah kelamin jantan (75,00%) dan kelangsungan hidup (86,67%) tertinggi bila dibandingkan dengan kontrol (40,00 % dan 77,78%) dan perlakuan dengan 17-α methyltestosterone (MT) 500 μg/L (62,50% dan 46,67%). Dengan demikian, ekstrak tanaman purwoceng dapat digunakan untuk maskulinisasi ikan cupang melalui perendaman artemia dengan dosis terbaik adalah 20 mg/L yang membuat nisbah kelamin jantan ikan cupang lebih tinggi dari kontrol.
Keyword: artemia, Betta splendens, ekstrak tanaman purwoceng P. alpina, maskulinisasi, perendaman

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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