Judul: Keanekaragaman Jenis Ular di Areal Perkebunan Sawit PT Sukses Tani Nusasubur Kalimantan Timur
Abstrak: Ecologically, snake has been known to functions as biological pest control. The aim of this research is to assess snake diversity in oil palm plantation area of PT Sukses Tani Nusasubur in East Kalimantan. The survey found 22 individual of snakes consisting of eight species in four families. Xenopeltidae (1 species), Colubridae (5 types), Pythonidae (1 species), and Elapidae (1 species). Two species of snakes, Naja sumatrana and Python reticulatus, is include in Appendix II of CITES. Snake species diversity is highest on karst habitats with Shanon Index of diversity of 1.74 and the lowest in the secondary forest habitat type with an index value of 0. Evenness index within oil-palm plantation are moderate, with low dominance of Dendrelaphis pictus. Highest level of evenness is found in karst habitat and lowest in the secondary forest habitat. Food habits analysis were only conducted for selected species with limited number of snake. The result only found reptile and amphibian as food, but unable to showed the function of snake as rodent control
Keyword: 

Judul: Studi Keanekaragaman Jenis dan Sebaran Spasial Ular pada Beberapa Tipe Habitat di Taman Nasional Tanjung Puting, Kalimantan Tengah
Abstrak: Snake is one part of herpetofauna with large number of species. At least 154 species from 10 families of snakes have been recorded from Borneo island (Stuebing and Inger, 1999). Although information about snakes diversity is already available, however it is too general. Specific information about snakes diversity, especially in the conservation area is still very limited. Tanjung Puting National Park (TPNP) is one of the conservation area in Indonesia that have limited information about snakes diversity. Whereas, TPNP have many type of ecosystems as well as snakes habitat. The objectives of this research were to identify species diversity and mapping the spatial distribution of snakes in TPNP. Data were collected about 24 days on April - May 2008 at 6 habitat types; shrub, secondary swamp forest at Beguruh, secondary swamp riverine forest at Sekonyer Kanan River, primary swamp forest, mixed forest at Camp Tanjung Harapan, and mixed forest at Camp Leakey. Data were collected using Visual Encounter Survey (VES) with randomized-walk design method (Heyer et al., 1994) . In total 14 species and 12 genus from 4 families of snakes were recorded during the surveys. The species richness represents 9,09 % of snakes in Borneo island. All of the species are not protected by Indonesian government laws and non-endemic species. There were two species categorized as Appendix II CITES, which are Naja sumatrana and Python reticulatus. The highest species richness was recorded in Camp Tanjung Harapan. These habitat are ecotone area and has a high number of snakes prey. Lowest species richness was found in primary swamp forest, whereas no snake was recorded in shrub habitat. Spatial distribution of snake in each habitat type are affected by difference of habitat characteristics, especially cover, water, and easiness to get prey. Keywords: diversity, spatial distribution, snake, TPNP
Keyword: 

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.
Keyword: