Judul: Tata Niaga, Parameter Demografi, Morfometri, Panenan dan Karakteristik Habitat Ular Sendok Naja sputatrix (Boie, 1827) di Provinis Jawa Timur.
Abstrak: Spitting cobra (Naja sputatrix Boie 1827) has been harvested and traded in local and international market, yet there was still no suficient data concerning its population and habitat. The main purposes of this research was to analyze the trading system, demographic parameters, morphometry and habitat characteristics of spitting cobra in East Java Province. The actors involved in the trading systems functioning as harvesters, collector, sub agen, agents, and also domestic users which likely had no allegiance between them and very much influenced by the market. Morphometrics measurement of the speciments, showed that male snakes had a longer bodysize compare to females, SVL were 999,2 cm and 998,9 cm respectively,which 81,90% of total harvested speciments were adult spitting cobras. The females dominated the harvested population of all trade actors, up to 90,54%, this might be an effect of harvesting pattern where the harvesters conducted catching outside the nests. Such pattern would be a threat for the population of the snake. Spitting cobras had no habitat preference and could easily adapted with different kinds of environment.
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Judul: Tata Niaga, Kelimpahan Dan Karakteristik Habitat Ular Jali Ptyas Mucosus (Linnaeus 1758) Di Jawa Tengah
Abstrak: The research of oriental rat-snake’s (Ptyas mucosus Linn 1758) abundance and its habitat is still rare. Oriental rat-snake is classified as a commerce species and is listed on Appendix II of CITES. This study was aimed at measuring the abundance and morphometric characteristic of oriental rat-snake in Central Java. In the present study, harvesting abundance was obtained from 7 major collectors, 3 medium collectors, 4 small collectors and 4 hunters/professional catcher. Information was also obtained by interviewing the managers of both of BKSDA and LIPI. The morphometric data collected from 159 living and 131 dead specimens from major collectors. Harvesting abundance derived from the average of rat-snakes that was received by major collectors. Descriptive analysis was used to process data morphometric. The multiple linier regressions were performed to determine the relationship between body mass and body size variables. In the trading system, there were traders, trade’s chain and price factors that influance its. The harvesting abundance of oriental rat-snake in Central Java were estimated annually a 132 000. Its abundance was mainly influenced by natural factor, especially paddy's crops cycles. Based on the descriptive analysis of morphometric data obtained, males had longer SVL and greater body masses than females of the same body length. Average of male’s snout-vent length was 142,67 (SD=14,09) and body mass is 0,95 kg, while for female’s SVL was 140,45(SD=12,99) and body mass is 0,93 kg. The analysis showed insignificant differences in body size between the sexes and in each collector’s level. At present, abundance of oriental rat-snake can support commercial harvesting. Habitat characteristic of oriental rat-snake’s nest were consisted of nine variables, i.e. hole and soil moisture, hole and soil temperature, soil pH, location altitude, distance from water and settlement, and slope. However, further studies are needed to assess sustainable levels of harvesting.
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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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