Judul: Sago (Metroxylon sagu Rottb.) Agroforestry Design Based on Morphological Characters, Physical Environment and Productivity in National Siberut Park
Abstrak: Sagu (Metroxylon sagu Rottb.) merupakan tumbuhan penghasil pati tertinggi dengan kandungan karbohidrat 94 g per 100 g. Potensi sagu dapat mengatasi permasalahan kekurangan pangan nasional dan mengurangi ketergantungan masyarakat terhadap beras. Tujuan penelitian yaitu menganalisis karakter morfologi, fisik lingkungan dan produktivitas sagu untuk mendapatkan rancangan agroforestri sagu berkelanjutan di kawasan Taman Nasional Siberut. Metode yang digunakan yaitu observasi dan analisis vegetasi. Fisik lingkungan habitat sagu terbagi menjadi dua kategori lahan, yaitu lahan lembab dan lahan basah. Karakter morfologi sagu (ukuran, bentuk dan jumlah) lebih unggul di Kecamatan Siberut Utara. Sagu siap panen, umumnya memiliki tinggi batang 8-10 m. Produktivitas sagu di Kecamatan Siberut Utara dan Kecamatan Siberut Barat masing masing menghasilkan 16,88 ton/ha dan 14,69 ton/ha. Rancangan agroforestri berbasis sagu yang direkomendasikan menggunakan jarak tanam 10 x 10 m yang menghasilkan tegakan sagu ideal sekitar 100 pohon/ha/tahun. Tumbuhan pendukung agroforestri, antara lain pangan, obat, rotan manau serta ternak lebah dan ikan., Sago is the highest starch-producing plant with a carbohydrate content of 94 g per 100 g. Potential of sago can overcome the problem of national food shortages and reduce peoples dependence on rice. Purposes the study were to analyze of morphological characters, physical environment and productivity of sago to obtain a sustainable sago agroforestry design in the Siberut National Park area. Methodsused were observation and vegetation analysis. Physical environment of the sago habitat wasdivided into two categories of land, moist land and wetlands. Morphological characters of sago (size, shape and total) were superior in North Siberut District. Sago is ready to harvested, generally has a stem height of 8 - 10 m. Sago productivity in North Siberut and West Siberut sub-districts produced 16,88 tons/ha and 14,69 tons/ha. Recommended sago-based agroforestry designed uses a spacing of 10 x 10 m which produces an ideal sago stand of around 100 trees/ha/year. Supporting plants for agroforestry include food, medicine, manau rattan as well as beekeeping and fish.
Keyword: agroforestry, morphological characters, physical environment, productivity

Judul: Identifikasi Berbagai Aksesi Sagu (Metroxylon spp.) di Taman Nasional Siberut, Kepulauan Mentawai, Sumatera Barat
Abstrak: Tumbuhan sagu (Metroxylon spp.) merupakan salah satu tumbuhan penghasil karbohidrat yang potensial untuk dikembangkan dan memiliki kandungan karbohidrat terbesar dibanding tumbuhan penghasil karbohidrat lain. Keragaman jenis tumbuhan sagu di Indonesia masih banyak yang belum diketahui. Penelitian ini bertujuan mempelajari keragaman tumbuhan sagu berdasarkan karakter morfologi, karakter produksi dan karakter genetik yang dilakukan secara langsung melalui pengukuran (kuantitatif) dan pengamatan visual (kualitatif) di Taman Nasional Siberut, Kepulauan Mentawai, Sumatera Barat. Karakter genetik diamati menggunakan metode Random Amplified Polymorphic DNA (RAPD). Terdapat enam aksesi sagu yang diamati di dua Kecamatan Siberut Barat dan Siberut Utara, yaitu aksesi Saikoat, Limu, Betaet, Ukra, Sirilanggai dan Sibeotcun yang keseluruhan aksesi tersebut termasuk jenis sagu yang tidak berduri. Berdasarkan karakter morfologi, terdapat perbedaan dari keenam aksesi, seperti habitus dan habitat tumbuhan, bentuk tajuk, bentuk dan ukuran batang, jumlah daun, ukuran daun dan anak daun, warna kulit batang, warna empulur, warna pati, serta warna kuncup daun muda anakan. Rata-rata produksi pati kering berbagai aksesi sagu sebesar 312,68 kg batang-1. Aksesi Ukra merupakan aksesi yang memiliki produksi pati kering tertinggi sebesar 544,37 kg batang-1. Produktivitas sagu di Taman Nasional Siberut berdasarkan perhitungan jumlah pohon sagu siap panen per hektar didapatkan produktivitas sagu sebesar 15,79 ton hektar-1 tahun-1. Berdasarkan analisis karakter genetik (RAPD), terdapat keragaman yang cukup dekat dari keenam aksesi sagu yang terdapat di Taman Nasional Siberut, dengan nilai koefisien kemiripan berkisar antara 61% hingga 77%. Aksesi Ukra memiliki nilai koefisien kemiripan paling jauh dengan aksesi yang lainnya yaitu sebesar 61%., Sago (Metroxylon spp.) is one of the potential carbohydrate-producing plants to be developed and has the largest carbohydrate content compared to other carbohydrate-producing plants. The diversity of sago plant species in Indonesia is still largely unknown. This study aims to study the diversity of sago plants based on morphological, production, and genetic characteristic which were carried out directly through measurements (quantitative) and visual observations (qualitative) in Siberut National Park, Mentawai Islands, West Sumatra. Genetic characters were observed using the Random Amplified Polymorphic DNA (RAPD) method. There were six accessions of sago observed in two sub-districts of West Siberut and North Siberut, namely accessions of Saikoat, Limu, Betaet, Ukra, Sirilanggai, and Sibeotcun all of which included the thornless type of sago. Based on morphological characters, there were differences between the six accessions, such as habitus and plant habitat, crown shape, stem shape and size, number of leaves, leaf size and leaflets, stem bark color, pith color, starch color, and color of young leaf buds. The average dry starch production of various accessions of sago was 312.68 kg stem-1. The Ukra accession was the accession with the highest dry starch production of 544.37 kg stem-1. Sago productivity in Siberut National Park based on the calculation of the number of ready-to-harvest sago trees per hectare obtained sago productivity of 15.79 tons hectare-1 year-1. Based on genetic character analysis (RAPD), there is a fairly close diversity of the six sago accessions found in Siberut National Park, with similarity coefficient values ranging from 61% to 77%. Ukra accession has the closest similarity coefficient with other accessions, which is 61%.
Keyword: character, diversity, genetics, morphology, production

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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