Judul: Validation of the Red-Eared Slider Turtle Trachemys scripta elegans (Wied-Neuwied, 1839) Traded in Bogor Based on Cytochrome Oxydase Subunit I (COI) Gene Markers
Abstrak: Kura-kura Brazil Trachemys scripta elegans (Wied-Nuwied, 1839), termasuk hewan introduksi semi akuatik di Indonesia. Namun, keberadaannya dikhawatirkan dapat mengancam spesies lokal akibat pelepasliaran di perairan bebas. Tujuan penelitian ini adalah untuk validasi secara molekuler spesies kura-kura Brazil (Trachemys scripta elegans) di wilayah Bogor, Jawa Barat yang didasarkan pada marka gen COI. Metode yang digunakan meliputi isolasi dan ekstraksi DNA, elektroforesis, amplifikasi, serta sekuensing. Analisis data berupa analisis morfologi, pensejajaran nukleotida, validasi fragmen COI, perhitungan jarak genetik, konstruksi pohon filogenetik, dan keragaman haplotype. Hasil didapat berupa 11 DNA target yang memiliki jarak genetik < 3% dengan Trachemys scripta elegans, hubungan kekerabatan yang dekat dengan Trachemys scripta elegans, serta keragaman haplotype yang sedang. Dapat disimpulkan bahwa sampel berpotensi menjadi invasif jika dilepasliarkan secara bebas dan tervalidasi dengan Trachemys scripta elegans berdasarkan identifikasi molekuler.
Keyword: gen COI, identifikasi molekuler, T. scripta elegans

Judul: Analisis Kekerabatan Genetik Labi-Labi Bengkulu (Pelochelys cantorii) Berdasarkan Gen 12S rRNA Pada Mitokondria
Abstrak: Pelochelys cantorii merupakan salah satu spesies kura-kura air tawar besar yang dikenal dengan labi-labi raksasa asia dari famili Trionichidae dan ordo Testudines. Pelochelys cantorii dilaporkan telah mengalami penurunan populasi disebabkan adanya eksploitasi berlebih, fragmentasi habitat dan juga sering tertangkap tidak sengaja oleh nelayan. Tujuan penelitian ini adalah memastikan spesies Pelochelys cantorii yang tertangkap di Bengkulu menggunakan gen 12S rRNA dan menganalisis posisi filogenetiknya dengan beberapa spesies kura-kura yang lain. Sampel DNA diekstraksi dari darah 2 ekor labi-labi (P1 dan P2) yang tertangkap di Bengkulu. Ruas gen 12S rRNA diamplifikasi dengan mesin PCR kemudian runutan nukleotidanya disekuensing. Hasil sekuensing gen 12S rRNA sampel P1 dan P2 masing-masing 959 bp dan 901 bp, dan setelah dilakukan alignment dengan beberapa spesies kura-kura yang lain diperoleh panjang DNA sebesar 950 bp (ada gap). Hasil alignment menunjukkan bahwa jarak genetik terhadap P. cantorii dengan NC015825 sebesar 0.007 dan 0.012 masing-masing P1 dan P2. Hasil rekontruksi pohon filogeni dengan metode Neighbour Joining menempatkan Pelochelys dalam satu klad dengan labi-labi raksasa yang lain, yaitu Chitra indica., Pelochelys cantorii is one of large freshwater turtle species known as the Asian giant turtle from the Trionichidae family and the order of Testudines. Pelochelys cantorii has been reported of experienced a decrease number of population caused by large exploitations, habitat fragmentation, and also unplanned caught by fisherman. The result of this study is to analyze the pelochelys cantorii using 12S rRNA and the filogenetic position with other turtles species. The DNA samples were extracted from 2 tutles (P1 and P2) that caught in Bengkulu. The 12S rRNA gene segment was amplified using PCR technique and sequenced the nucleotides materials. The results for each samples are 959 bp for P1 and 901 bp for P2, after aligning them with several turtles species, the DNA length was 950 bp (gap). The alignment results show that the genetic distance to P. cantorii with NC015825 is 0.007 and 0.012 respectively P1 and P2. The rescontruction of phylogenetic tree were using Neighbour Joining method by placing the Pelochelys into one clad with the giant turtle, named Chitra indica.
Keyword: 12S rRNA gene, Pelochelys cantorii, genetic kinship

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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