Judul: Variasi Gene Cytochrome Oxidase 1 pada Apis andreniformis dan Apis dorsata
Abstrak: Distribusi lebah madu Apis andreniformis dan A. dorsata (Hymenoptera: Apidae) adalah di Asia Tenggara, termasuk Indonesia. Analisis morfologi untuk kedua spesies lebah ini sudah banyak dilakukan di Indonesia, namun belum ada data DNA mitokondria berdasarkan gen cytochrome oxidase 1 (CO1). Penelitian ini bertujuan untuk menganalisis variasi gen CO1 A. andreniformis dan A. dorsata. Analisis filogenetik pada lebah A. andreniformis dilakukan dengan menggabungkan database gen CO1 A. andreniformis asal Nepal dan Cina, lebah A. dorsata digabungkan dengan database gen CO1 A. dorsata asal Kalimantan Selatan, Sabah, Sarawak dan Cina. Hasil sekuen gen CO1 parsial A. andreniformis adalah 582 pb dan A. dorsata 507 pb. Jarak genetik terendah antara sampel A. andreniformis asal Padang Pariaman dengan Nepal dan Cina. Jarak genetik tertinggi pada A. dorsata antara sampel asal Sukabumi dengan sampel asal Kalimantan Selatan, Sabah, Sarawak dan Cina. Analisis filogenetik berdasarkan gen CO1 menunjukkan A. andreniformis asal Indonesia dan Cina mengelompok menjadi satu grup. Analisis filogenetik A. dorsata menunjukkan bahwa sampel asal Sukabumi terpisah dengan A. dorsata asal Kalimantan Selatan, Sabah, Sarawak, dan Cina
Keyword: Apis, open nesting honey bee, dwarf honey bee, giant honey bee, DNA mitochondria, CO1 gene

Judul: Mitochondrial DNA Variation of Cytochrome C Oxidase  1 (COX1) Gene, Cytochrome C Oxidase 2 (COX2) Gene, and Intergenic Spacer  (IGS) COX1/COX2 Apis dorsata from Sumatra
Abstrak: Apis dorsata merupakan lebah madu hutan dengan distribusi di Asia tropis dan subtropis, salah satunya Sumatra, Indonesia. Penelitian terkait molekuler A. dorsata di Sumatra masih belum banyak dilakukan. Oleh sebab itu, penelitian ini bertujuan menganalisis variasi molekuler A. dorsata Sumatra menggunakan gen COX1, COX2, dan IGS COX1/COX2 DNA mitokondria (mtDNA). Analisis molekuler terdiri dari ekstraksi DNA menggunakan metode Cetyl Trimethyl Ammonium Bromide (CTAB) dan presipitasi alkohol dengan modifikasi, amplifikasi dan sekuensing DNA, serta ,analisis bioinformatika dan filogenetik. Sampel dikoleksi dari empat provinsi di Sumatra: Riau, Jambi, Sumatra Selatan dan Kepulauan Bangka Belitung. Hasil menunjukkan A. dorsata asal Sumatra pada gen COX1 dan COX2 memiliki variasi sebanyak delapan dan enam nukleotida, yang menghasilkan enam haplotipe untuk tiap marka. Sekuen IGS COX1/COX2 memiliki panjang total 25 pb dan tidak ada variasi nukleotida. Setiap lokasi kecamatan di Sumatra Selatan membentuk haplotipe spesifik pada gen COX1 dan menunjukkan variasi genetik yang tinggi. Berdasarkan pohon filogenetik, gen COX1 lebih informatif daripada gen COX2 dalam menunjukkan kekerabatan lebah A. dorsata Sumatra. Pada pohon filogenetik COX1, A. dorsata asal Jambi, Riau, Kepulauan Bangka Belitung, serta satu koloni asal Kec. Peninjauan, Kab. Ogan Komering Ulu, Sumatra Selatan berada dalam satu kluster., Apis dorsata is a forest honeybee distributed in tropical and subtropical Asia, one of which is Sumatra, Indonesia. The molecular study of A. dorsata in Sumatra has not been widely carried out. Therefore, this study aimed to analyze molecular variations of Sumatran A. dorsata using the COX1 gene, COX2 gene, and IGS COX1/COX2. The molecular analysis consisted of DNA extraction using the Cetyl Trimethyl Ammonium Bromide (CTAB) and alcohol precipitation with modification, DNA amplification and sequencing, bioinformatics and phylogenetics analysis. Samples were collected from four provinces in Sumatra: Riau, Jambi, South Sumatra, and Bangka Belitung Islands. The results showed that Sumatran A. dorsata in the COX1 and COX2 genes had eight and six nucleotide variations, resulting in six haplotypes for each marker. The total length of the IGS COX1/COX2 sequence was 25 bp and there was no nucleotide variation. Each sub-district location in South Sumatra formed a specific haplotype in the COX1 gene and showed high genetic variation. Based on the phylogenetic tree, the COX1 gene is more informative in presenting the genetic relationship of A. dorsata from Sumatra than the COX2 gene. In the COX1 phylogenetic tree, A. dorsata from Jambi, Riau, Bangka Belitung Islands, and a colony from Peninjauan Sub-district, Ogan Komering Ulu Regency, South Sumatra is in one cluster.
Keyword: DNA mitokondria, filogenetik, jarak genetik, Sumatra Selatan, variasi haplotipe, genetic distance, haplotype variation, mitochondrial DNA, phylogenetic, South Sumatra

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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