Judul: Pengaruh Dosis Aromatase Inhibitor Terhadap Nisbah Kelamin Ikan Betta (Betta Sp.)
Abstrak: Ikan Betta (Belta sp.) merupakan salah satu jenis ikan hi as air tawar yang populer dan banyak diminati, terutama ikan betta jantan, karena memiliki bentuk sirip dan warn a tubuh yang lebih menarik serta tingkah laku yang lebih agresif dibandingkan betinanya. Kelebihan tersebut juga menyebabkan ikan betta jantan memiliki harga jual yang lebih tinggi dibandingkan betinanya, dan mendorong orang membuat populasi I110110sex jantan. eara yang umum dilakukan untuk memperoleh populasi l11onosex adalah melalui teknik manipulasi pengarahan kelamin (sex reversaT). Selama ini teknik sex reversal untuk memperoleh populasi I110110sex jantan (maskulinisasi) banyak dilakukan menggunakan hormon 17a.-metiltestosteron (MT) baik melalui oral, penyuntikan maupun dengan cara perendaman. Namun akhir-akhir ini penggunaan hormon MT mulai dibatasi karena diduga menjadi salah satu penyebab pencemaran lingkungan, dan diduga dapat menyebabkan kanker pada manusia (Phelps el al., 2001). Sehingga perlu ditemukan alternatif metode untuk sex reversal yang lebih aman.
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Judul: Pengaruh pemberian hormon 17 alpha-metiltestosteron secara oral terhadap nisbah kelamin Ikan Betta (Betta splendens Regan)
Abstrak: Percobaan ini dilakukan di Laboratorium Pengembangbiakan Ikan, Jurusan Budidaya Perairan, Fakultas Perikanan IPB, Darmaga-Bogor. Lama penelitian tiga bulan, mulai akhir Juni 1994 sampai akhir September 1994. Tujuan percobaan ini adalah untuk mengetahui pengaruh pemberian nauplius Artemia yang telah direndam dalam larutan hormon 17a metiltestosteron (MT) terhadap nisbah kelamin ikan betta. Ikan uji yang digunakan adalah larva ikan betta yang berumur 15 hari. Perlakuan diberikan selama 15 hari, sampai ikan berumur satu bulan. Selama perlakuan larva diberi nauplius Artemia yang telah direndam selama 24 sampai 28 jam dalam larutan hormon MT dengan dosis 0, 2, 4 dan 8 mg/1. Pakan diberikan secara ad libitum dengan frekuensi 4 kali sehari, yaitu pukul 06.00, 10.00, 14.00 dan 18.00 WIB. Analisis jenis kelamin dilakukan pada waktu ikan berumur tiga bulan. Hasil percobaan menunjukkan bahwa nilai nisbah kelamin ikan uji antar perlakuan dan kontrol dalam setiap ulangan tidak berbeda nyata. Suhu media selama perlakuan berkisar antara 24°C sampai 26°C. Tingkat kelangsungan hidup ikan uji berkisar antara 81,7% sampai 95,7%. Kesimpulan yang diperoleh dari hasil penelitian ini bahwa pemberian hormon sejak ikan berumur 15 hari sampai berumur 30 hari, tidak merubah nilai nisbah kelamin normal.
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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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