Judul: As partial requirement fulfilment for the Doctorate Degree in plant taxonomy
Abstrak: An account of the diversity, distribution, and taxonomy of the Asteraceae in Sumatera is given, There are 133 species of74 genera in 11 tribes, New species are recoqnized in this study, Prenanthes L. (2 species), Senecio L. (1 species), and Emilia sonchifolia (L.) DC (1 variety). The tribe Heliantheae is the largest, with 28% ofthe total number ofthe genera, followed by Astereae with 15%, Inuleae 12%, Senecioneae 10%, Anthemideae, Eupatorieae and Lactuceae 8%, the' other tribes are represented by 4% or less, The most diverse genus is Blumea DC with 14 species. Other genera are only represented by 10 species or less, usually 3, or 2, or, more usually, by 1 species only. In terms ofindigenous and endemic species, Sumatera is richer than Java, There are 43 important weed species, which were introduced from tropical America, Africa, Asia and Europe. Among these Chromolaena odorata (L.) RM. King & H Rob. and Mikania micrantha Kunth are reported as the most noxious ones. Studies on 9 species of Vernonia Schreb, in Sumatera were conducted to find distinct characters to support their taxonomic delimitation. Foliar trichome types may have taxonomical value to delimit sections. However, further study on many more specimens form larger geographical areas such as Malesia is required combined with other investigations, i.e. chemotaxonomy, pollen morphology or DNA analyses to obtain a better idea for new proposals of redefinitions of the sections.
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Judul: Artabotrys (Annonacea) in East Malesia
Abstrak: Studies on the taxonomy of the genus Artabotrys R. Br. ( Annonaeceae ) in East Malesia were based on morphological characters by examining a large number of Herbarium Bogoriense (BO), Celebense (CEB), Manokwari (MAN), Departemen of Forest Lae (LAE) and living plants of Bogor Botanical Garden. There are eight species which have been known previously: A. camptopetala Diels, A. gracilis King., A. hexapetalus (L.f.) Bhandari, A. inodorus Zipp., A. macranthus Holthuis, A. speciosus Kurz., A. suaveolens Blume, A. sumatranus Miq. and A. venustus King. Four new species are proposed in this treatment : A. desmidantha Diels ex Triasti., A. longipetalus Triasti., A. palmatiflorus Triasti., and A. trichofolius Triasti.. An identification key and detailed discription are provided for taxa. Artabotrys suaveolens Blume is widely distributed. While A. camptopetala, A. desmidantha, A. longipetalus, A. inodorus, A. palmatiflorus and A. trichofolius have a limited distribution. New Guinea is the area with the highest diversity of Artabotrys species in East Malesia. A phylogenetic analysis with Cyathocalyx sumatranus as outgroup, shows three major groups. The first group is Cyatocalyx sumatranus. The second group is A. macranthus which has the closest relationship with the outgroup. The third group separated from the other group by the synapomorph characters 2 (leaf length), 3 (hook), 11 (carpel shape), 14 (number of ovule) and 15 (position of seed).
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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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