Judul: Efektivitas aromatase inhibitor melalui perendaman pada larva ikan lele sangkuriang, Clarias sp., yang berumur 0, 2, dan 4 hari setelah menetas
Abstrak: Maskulinisasi ikan lele telah dapat dilakukan engan menggunakan aromatase inhibitor (AI). Dalam sex reversal ikan lele, periode kritis diferensiasi seks merupakan faktor penting yang harus diketahui untuk efektifitas sex reversal.
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Judul: Efektivitas aromatase inhibitor pada perendaman embrio terhadap sex reversal ikan lele Sangkuriang clarias sp.
Abstrak: Produksi ikan lele jantan perlu dilakukan untuk dapat meningkatkan produksi ikan lele, yang terus meningkat. Salah satu cara untuk produksi ikan lele jantan adalah sex reversal. Penelitian ini bertujuan untuk mengetahui dosis yang efektif untuk melakukan perendaman embrio ikan lele stadia bintik mata dengan aromatase inhibitor (AI) agar dapat menghasilkan ikan jantan secara optimal. Penelitian ini menggunakan 3 perlakuan dan 1 kontrol yaitu perendaman embrio stadia bintik mata dengan dosis Al 10, 20, dan 30 mg/l air. Seratus lima puluh telur yang telah dibuahi dimasukkan ke dalam akuarium berukuran 20x20x20 cm lalu dilarutkan Al pada saat fase bintik mata, salama 18 jam. Lalu dipelihara dalanı akuarium 40x60x40 cm selama 45 hari. Perlakuan perendaman embrio selama 18 jam dalam aromatase inhibitor dengan dosis 30 ing/! efektif untuk meningkatkan persentase jantan sebesar 20,26% dari kontrol menjadi 67,46% (P<0,05). Sesuai hasil penelitian ini dapat disimpulkan bahwa perendaman telur ikan lele yang telah dibuahi dalam larutan Al dosis 30 mg/l dapat meningkatkan jumlah ikan jantan secara efektif, serta perendaman embrio dengan aromatase inhibitor tidak mempengaruhi derajat penetasan telur dan tingkat kelangsungan hidup ikan leie sangkuriang Clarias sp..
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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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