Judul: Studi Keanekaragaman Jenis Tumbuhan Pakan Bekantan (Nasalis Larvatus) Di Taman Nasional Tanjung Puting Kalimantan Tengah (Studi Kasus Di Areal Research Pondok Ambung )
Abstrak: Bekantan (Nasalis larvatus) is one of an endemic primate in Indonesia, especially in Kalimantan and this species protected by the law. Bekantan had a priority to be an object in food ecology research because of this species is rare and also endemic. Their habitat limited in forest around the rivers, mangrove and peat swamp forests and nowadays some of that threatened by human activities. On February, 22nd 2008 fire attack Pondok Ambung Areal Research part of Tanjung Puting National Park which burned around 5,6 ha. This damage decrease the number of bekantan population along the year. Because of that, conservation action needed into population of bekantan, ecosystem of peat swamp forest and swamp forest around the rivers. Study about food variety in bekantan especially at Tanjung Puting National Park, Province of Center Kalimantan really important as an a conservation action in population of bekantan. Direct and indirect identification of feed variety was used as method to collect the data. Direct observation was conducted for 12 days on 4 groups of bekantan. Vegetation analyze was conducted by using line transect method. This study found 11 species that consumed by bekantan in 12 observation days. From 12 time monitoring, most after consumed vegetation is Genua motleyana, but they just consumed the leaves. Crudia teysmanii and Eugenia zeylanica are another choice often Genua motleyana. In Eugenia zeylanica, bekantan just consumed the flowers and leaves. Comparison between leaves : flowers : fruit is 79% : 18 % : 3%. Result from vegetation analysis in swamp forest and lowland forest found 22 food variety of bekantan. Result from species diversity indexs (Shannon- Wieners index) showed foods variety level in swamp forest is more diverse than in lowland forest. This difference may influenced by difference of seasons that related to tree phenology. If was found 22 foods species of bekantan in swamp forest and lowland forest, among them Genua motleyana, Syzygium leucoxylon, Neoscortechinia sp., Eugenia zeylanica and Crudia teysmanii. Bekantan prefer to consumed leaves than flowers and fruits.
Keyword: 

Judul: Karakteristik Habitat dan Wilayah Jelajah Bekantan (Nasalis Larvatus, Wurmb) di Hutan Mangrove Desa Nipah Panjang Kabupaten Kubu Raya Provinsi Kalimantan Barat
Abstrak: Bekantan is a spesies of the primates who lived at rivarian forest and mangrove forest in Kalimantan island. Bekantan was protected by law and regulation No.5 of 1990 about nature resources conservation and the ecosystem which is showed the status of bekantan. This species also included in Appendix I of CITES and was categorized as susceptible species on IUCN Red Data Book 1978. The population of bekantan has decrease drastically through habitat destruction because of that it has to do a research about habitat characteristic and homerange of bekantan at Nipah Panjang Village, Batu ampar. The information will be one of the variable to get sustainable populatin management of bekantan. The species of vegetation and ground vegetation that using as habitat and food resources for bekantan was already calculated using plot line method with the length of the line is 100 m and width of the line is 50 m. To ,measuring the dayrange of bekantan that based on DR, RM, and NPS in radio tracking that base on GPS. It was started when the bekantan leave sleeping tree on 05.30 AM until the bekantan get into the next sleeping tree on 06.30 PM. Scope of the homerange was determined using Minimum Convex Polygon method in software Arc view. This method can connected outside coordinate points on the activities place of bekantan. On the research site at Lalau river and Sukamaju River was identified is spesies of vegetations that used at food resources by bekantan. The species of vegetation that often consumed by bekantan are R. apiculata, R mucronata, B. gymnorrhiza, B. parviflora and Acrostchum speciosum. Estimation homeranges scope of group I is 13.4 ha in Lalau riverine and group II in Suka Maju riverine is 38 ha. Daily range group of bekantan in Suka Maju river is 984.9 m on the average. It is different with DR from group of bekantan at Lalau river is 756.7 m on the average. The differences of DR caused by some factors like foods abudances, human disturbing, and the rise and fall of the tides and water salinity. Bekantan using strata B on the high at 20 - 30 m for their vertical movement to activities like eating, resting, calling, moving, and also to chose the sleeping tree has influenced by the food avaibility like shoot of youg leaves and young leaves and security factor from predators attacks like monitor lizards crocodiles and mangrove snakes. The habitat of bekantan at Nipah Panjang is Mangrove rivarian forest with estimation homerange scope group of bekantan in Lalau river is 13.4 ha, value of DR is 756.7 m and RM 367.5 m on the average. The home range scope group of bekantan in Suka Maju river is 38 ha, value of DR is 984.9 m on the average and RM is 367.82 m on the average.
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: