Judul: Penggunaan saringan untuk mencegah infeksi parasit myxosperea pada pemeliharaan benih ikan mas
Abstrak: Penelitian ini bertujuan untuk mengetahui efektifitas sistim saringan terhadap infeksi Myxosporea pada benih ikan mas (Cyprinus carpio L.). Ikan yang digunakan adalah larva ikan mas yang diperoleh dari pemijahan pada kolam-kolam bebas parasit. Saringan dibuat dari tong plastik dengan kapasitas 100 liter, yang diisi bahan-bahan berturut-turut dari dasar tong adalah baskom berlubang kecil-kecil, kerikil, ijuk, pasir, kerikil, ijuk, pasir dan kerikil. Tebal masing-masing adalah kurang lebih 10 cm. Air mengalir ke dalam saringan melewati pipa pralon dengan sistim "upwelling". Pengamatan dilakukan setiap minggu selama 8 minggu (2 bulan) dengan mengambil 5 ekor ikan dari setiap ulangan dan setiap perlakuan. Pemeriksaan parasit dilakukan secara makroskopis dan mikroskopis yaitu dengan melihat bagian insang untuk mengetahui insidensi Myxosporea pada kolam yang disaring (F) dan yang tidak disaring (NF). Kemudian data masing masing parasit yang diperoleh dibandingkan antara kolam F dengan kolam NF.
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Judul: Kerentanan Benih Ikan Mas (Cyprinus carpio L.) Terhadap Myxosporea
Abstrak: Penelitian ini bertujuan untuk mempelajari morfologi Myxosporea yang menyerang insang dan otot daging serta mendeterminasinya, mempelajari kerentanan berbagai ukuran benih ikan mas terhadap serangan Myxosporea, serta memeriksa isi usus ikan mas sebagai salah satu petunjuk dari penularan. Tempat penelitian di Balai Budidaya Air Tawar, Sukabumi, dalam kolam tanah berukuran 574 m² yang mendapatkan sumber air dari saluran irigasi dan saluran pembuangan penduduk. Penularan di kolam ini selama 21 hari, kemudian ikan-ikan dipindahkan kedalam bak-bak "fiberglass" yang berisi air dari sumur artesis. Penelitian ini dilakukan dari tanggal 11 Juni 1983 sampai dengan tanggal 8 September 1983. Pengamatan meliputi morfologi spora dan "cyste" Myxosporea pada insang dan otot daging, spora didalam isi usus, frekuensi kejadian Myxosporea, intensitas Myxosporea, distribusi "cyste" Myxosporea pada insang, serta mortalitas ikan mas. Sebagai data penunjang diamati kualitas air kolam serta air bak "fiberglass". ...
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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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