Judul: Komunitas Fitonematoda pada Tanaman Ubi Jalar (Ipomoea batatas L.)
Abstrak: Ubi jalar (Ipomoea batatas) merupakan salah satu komoditas penting dan menjadi bahan pangan pokok alternatif di Indonesia. Organisme Pengganggu Tanaman (OPT) merupakan penyebab penurunan produksi ubi jalar yang signifikan, salah satunya adalah nematoda parasit. Penelitian ini bertujuan mengeksplorasi keberadaan dan identifikasi komunitas nematoda parasit yang terdapat di ubi jalar. Penelitian dilakukan dengan mengambil sampel umbi, akar, dan tanah ubi jalar di dua lahan yang berbeda di Desa Cikarawang, ekstraksi nematoda, perhitungan populasi nematoda, pembuatan preparat semi permanen, pewarnaan nematoda dalam jaringan umbi, identifikasi morfologi nematoda, dan analisis data. Identifikasi nematoda dilakukan dengan pengamatan ciri morfologi antara lain morfologi anterior, organ reproduksi, dan posterior terutama bentuk ujung ekor. Di samping itu, studi pustaka dilakukan terhadap artikel terkait laporan fitonematoda ubi jalar di Indonesia. Nematoda parasit berhasil dideteksi pada sampel umbi dari Desa Cikarawang, Kecamatan Dramaga, Kabupaten Bogor dengan jumlah rata-rata 11 ekor/10 g umbi pada lahan 1 dan 6 ekor/10 g umbi pada lahan 2. Nematoda teridentifikasi dari ciri morfologi dan bentuk ujung ekor adalah juvenil 2 Meloidogyne spp. Berdasarkan penelusuran pustaka, fitonematoda lain pada tanaman ubi jalar di Indonesia antara lain Helicotylenchus spp., Criconomella sp., Rotylenchulus reniformis, Tylenchulus sp., Tylenchorinchus annulatus, Pratylenchus sp., Psilenchus sp., Hoplolaimus sp., Ditylenchus destructor dan Radopholus sp.
Keyword: Desa Cikarawang, Meloidogyne spp., morfologi nematoda

Judul: Inventarisasi Nematoda Parasit pada Umbi Ubi Jalar (Ipomoea batatas L.) di Kabupaten Bogor, Jawa Barat
Abstrak: Ubi jalar (Ipomoea batatas L.) merupakan komoditas penting di Indonesia. Nematoda parasit tanaman merupakan salah satu patogen utama ubi jalar yang dapat menurunkan kuantitas dan kualitas umbi. Penelitian ini dilakukan untuk mengidentifikasi nematoda parasit pada umbi ubi jalar konsumsi. Sampel didapatkan dari lima pasar di Kabupaten Bogor, Jawa Barat, yaitu Pasar Bojonggede, Cibinong, Ciampea, Leuwiliang, dan Jasinga. Nematoda diekstraksi dengan menggunakan metode pengabutan. Analisis komunitas nematoda dilakukan dengan menghitung nilai populasi absolut, frekuensi, dan kelimpahan. Pewarnaan dengan asam fuchsin digunakan untuk mendeteksi nematoda stadia telur, juvenil, dan dewasa. Preparat semipermanen digunakan untuk mempermudah pengamatan karakter morfologi dan identifikasi nematoda. Nematoda parasit terdeteksi pada tiga jenis ubi jalar. Nematoda parasit yang terindentifikasi adalah Meloidogyne, Pratylenchus, dan Helicotylenchus. Nematoda parasit yang memiliki populasi paling dominan adalah Meloidogyne populasi absolut 33,33 nematoda/100 g umbi, frekuensi 66,67%, dan kelimpahan 4 nematoda/100 g umbi pada sampel yang berasal dari Pasar Ciampea. Telur, juvenil termasuk J1, J2, J3, J4, dan betina dewasa Meloidogyne ditemukan di dalam umbi ubi jalar sakit.
Keyword: Absolute population, nematode morphology

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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