Judul: Studi Perilaku Simakobu (Simias concolor Miller, 1903) dan Pola Penggunaan Habitat di Area Siberut Conservation Programme, Sumatera Barat
Abstrak: Simakobu was one of endemic primates in Siberut island that become attention of Siberut Conservation Programme. This species was threatened mainly by heavy hunting and commercial logging by local people. This study aims to determine the behavior of simakobu and habitat use. This research was conducted from July 2011 until January 2012 in SCP. Pattern of behavior data collected via Scan Sampling. The results found that simakobu in exploiting their food used more sitting posture than hanging posture. Actively grooming often existed between female and juvenile and passively grooming existed on male. The highest percentage calls of simakobu was occurred at 07.00-08.00 am with loud call duration in 20-30 second. Simakobu often used space between the first branch of the tree to the canopy at 21-25 meter in height.
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Judul: Studi Ko-Habitasi Antara Simakoru (Simias concolor) dan Joja (Presbytis potenziani) di Area Siberut Conservation Program (SCP), Pulau Siberut-Kepulauan Mentawai Sumatera Barat
Abstrak: Siberut Island represented union of various endemic and unique plant and animal as effect of continually evolution process. One of uppermost example is four species of rndemic primate found in this island Both of Simakobu (Simias concolor) and Joja (Presbytis potenziani) representing some of endemic primates exploiting Siberut Island as habitat and lived at some habitat during more than hundred of year. Putman (1984) uttered that two or more species with some or similiar ecology eill not earn to coexist in same community. Therefore, This research is very attractive and requiared to be conducted in order to knowing habitat exploiting concept among Simakobu (Simias concolor) and Joja (Presbytis Potenziani). The aims of this research are: 1) Knowing pattern of location of activities according to dimension of space by Simakobu and Joja. 2) Knowing niche breadth quantitatively using by Simakobu and Joja. 3)Knowing overlapping niche among Simakobu and Joja
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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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