Judul: Identifikasi Postlarva Famili Gobiidae dari Muara Sungai Kedurang, Bengkulu melalui DNA Barcode
Abstrak: Gobiidae family fish postlarvae is one of seasonal migrant biota in a very large number. It is difficult to identify fishes species according to morphological characteristics of postlarvae because most of the fish identification guide is based on adult characters. The aim of this study was to identify the species composition of Gobiidae postlarvae that migrated in Kedurang estuary, Bengkulu through DNA Barcode. A total of 22 tails Gobiidae family postlarvae which were preserved in alcohol used as sampels. Segment of CO1 gene was used for barcoding purpose. Amplified of CO1 gene were successfully yielded in 700-800 bp fragment. Sample no 4, 5, 6, 10, 11, 12, 14, 16, 18, 21, 22 and 22 were identified as Stiphodon atratus, sample no 19 and 20 were identified as Amblyeleotris sungami while the sample no 3 were identified as of Novem Genus of subfamily Sicydiinae. Phylogeny tree reconstruction using the Neighbor Joining (NJ) bootstrap 1000x showed two major clades. One clade contains Stiphodon atratus and Novem Genus, other clades include only Amblyeleotris sungami
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Judul: Identifikasi Famili Galatheidae Berdasarkan Karakteristik Morfologi dan DNA Barcoding di Perairan Kepulauan Seribu, DKI Jakarta
Abstrak: Identifikasi spesies di antara keluarga Galatheidae terbukti sangat sulit karena pendeskripsian ciri morfologi banyak menimbulkan kontroversi dan lebih dari 900 spesies yang belum teridentifikasi secara morfologi. Teknik molekuler terbukti dapat mengidentifikasi dan mengkarakterisasi spesies dari Galatheidae yang belum teridentifikasi secara morfologi. Famili Galatheidae banyak ditemukan di ekosistem terumbu karang perairan dangkal. Penelitian ini bertujuan mengidentifikasi famili Galatheidae melalui pendekatan morfologi dan DNA barcoding yang berada di perairan Kepulauan Seribu, DKI Jakarta. Proses analisis pada penelitian ini terdiri atas ekstraksi, PCR, elektroforesis, dan sekuensing DNA serta penggambaran sampel morfologi dari famili Galatheidae. Target penanda untuk amplifikasi DNA menggunakan marka mitokondria lokus 16S. Sebanyak 73 sampel jaringan yang teranalisis dan teridentifikasi sebagai Allogalathea inermis, Allogalathea elegans, dan Galathea sp2 dengan nilai BLAST berkisar 83-100%. Bagian tubuh dari famili Galatheidae meliputi bagian karapas dan abdomen, sternal plastron, cephalothorax bagian anterior menunjukkan bagian antennule dan antena bagian kiri, maxilliped, pereiopod. Persentase tutupan terumbu karang dapat mempengaruhi sebaran spesies dari family Galatheidae. Rekonstruksi pohon filogenetik dari tiga spesies saling bertumpuk pada clade yang sama, menunjukkan secara genetik terdapat kekerabatan antara ketiga spesies. Terkonfirmasi secara morfologi ketiga spesies memiliki kedekatan dari ciri bentuk tubuhnya yang tidak berbeda jauh. Berdasarkan analisis molekular dari 73 sampel yang diteliti didapatkan tiga spesies yaitu Allogalathea elegans, Allogalathea inermis, dan Galathea sp2. Analisis molekuler kurang dapat mengkonfirmasi perbedaan yang dimiliki oleh ketiga spesies tersebut, meskipun demikian secara morfologi terdapat perbedaan pada bagian bentuk dan ukuran dari rostrum, bentuk ridges pada cervical groove, bentuk spine pada bagian margin movable finger dan fixed finger, dan ukuran setae pada setiap bagian tubuhnya. Kedekatan antar individu digambarkan dengan pohon filogenetik.
Keyword: Dekapoda, DNA Barcoding, filogenetik, spesies morfologi, terumbu karang

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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