Judul: Karakteristik Morfologi dan Anatomi Beberapa Spesies dan Kultivar Begonia Serta Analisis Hubungan Kekerabatannya
Abstrak: The distinctive asymmetric leaf, fleshy jointed stem, and showy flower are several common characters belongs to genus Begonia. Indonesia has more than 200 species Begonia which spread in Java, Sumatera, Kalimantan, Sulawesi, and Papua islands. Morphological and anatomical characters can be used to identify, classify, and determine plants relationship. The aims of this research were to identify morphological and anatomical characters of 11 species and cultivars of Begonia and to determine their relationship. Nine species and cultivars were successfully identified, while two species could not be identified. Seven species were identified as B. acetosa, B. bowerae. B. listada, B. thelmae, B. semperflorens, B. maculata, and B. lepida, while two cultivars could be identified as B. Argenteo-Gutata “Fanfare” and B. “Orpha C. Fox”. Study on morphological characters of 11 species and cultivars obtained six similar characters including simple leaf, alternate leaf arrangement, asymmetric leaf blade base, axillary’s inflorescence, and unisexual flower. Based on paradermal section, there were individual stomata, stomatal cluster, and both individual and stomatal cluster in leaves of Begonia. Begonia listada had the smallest stomatal size (35.0 x 22.9 μm) while B. maculata had the biggest (46.7 x 30.4 μm). Begonia “Orpha C. Fox” had the lowest stomatal density (23.2/mm2), while Begonia sp. 1 had the highest (108.7/mm2). Observation on transversal section showed that B. lepida had the smallest leaf thickness (162.5 μm) while B. listada had the highest (433.3 μm). The results of hierarchical cluster analysis based on morphological, anatomical, or both characters showed different patterns of relationship.
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Judul: Bali and Lombok species of begonia (Begoniaceae)
Abstrak: A taxonomic study of the genus Begonia Blume (Begoniaceae) in Bali and Lombok Islands were conducted based on morphological characters. Three previously known species ( Begonia coriaceae Hassk., B. longifolia Blume and B. tenuifolia Dryander ) five new species ( B. baliensis Girmansyah sp. nov., B. lempuyangensis Girmansyah sp. nov., B. lombokensis Girmansyah sp. nov., B .multibractea Girmansyah sp. nov, B. pseudomuricata Girmansyah sp. nov.,) are proposed. A key to species is included. A phylogenetic analysis was undertaken using PAUP vers. 4. Ob4. Programs Swofford (2000) with Hillebrandia sandwicencis as out group. This analysis be resulted a parsimonious cladogram, which shows that the Begonia divided into three subclade and belong to four section (Sphenanthera, Reichenheimia, Petermannia and Parvibegonia).
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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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