Judul: Perilaku Makan Gorila (Gorilla gorilla gorilla ) Di Pusat Primata Schmutzer Taman Margasatwa Ragunan Jakarta
Abstrak: Gorilla merupakan hewan diurnal teresterial. Makanan gorila berupa dedaunan dan buah, serta sedikit makanan berupa serangga. Penelitian ini bertujuan untuk mengidentifikasi perilaku harian dengan penekanan terhadap perilaku makan di dalam penangkaran Pusat Primata Schmutzer Jakarta. Pengamatan perilaku dengan metode focal animal sampling, dan ad libitum sampling. Hasil penelitian ini menunjukan bahwa persentase makan dan istirahat gorila lebih besar dibandingkan dengan perilaku lainya, yaitu 34,06% dan 29,32%. Hal ini dikarenakan gorila memiliki ukuran tubuh yang besar, sehinga waktunya lebih banyak dihabiskan untuk makan dan istirahat. Perilaku makan meningkat pada pukul 09.00, 12.00, dan 15.00. Persentase gorila mengambil pakan cenderung satu persatu 26,37%, pegang dengan satu tangan 17,69%, dan merobek dengan menggunakan gigi 24,19%. Posisi makan gorila lebih besar dengan duduk64, 36%, dan berbaring 27,10%.
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Judul: Feeding activity of orangutan (Pongo pygmaeus) in Schmutzer Primate Centre, Jakarta.
Abstrak: The study of feeding activity and feeding preference of eight orangutans has been conducted at Schmutzer Primate Centre, Jakarta, from March to September 2008. Feeding activity data collection was performed using focal animal sampling, while feeding preference of each object was collected by direct observation on the single cage. Based on 336 hours observation within 6 months, orangutan spent 53,18% of the time on feeding, 17,27% on resting, and 14,79% on traveling. The daily activity pattern was distributed bimodally with peaks at about 08.00 and 14.00. Feeding activity was greater in the morning (08.00–10.30) and in the afternoon (13.30– 16.00), while resting was greater at the midday. The percentage of fruits / vegetables consumed provided by the Schmutzer Primate Centre was greater (96,90%) than foods available in the exhibition cages (3,10%). Three species of plants were consumed frequently; fig (Ficus benjamina) (0,48%), rumput gajah (Pannisetum purpureum) (0,24%) and velvet tamarind (Dialium indicum) (0,21%), respectively. In addition, orangutan sometimes eat soil, feces, and insect. Based on feeding preference observed on the single cage, there were 3 kinds of foods highly preferred by orangutan, such as, egg, mango, and banana.
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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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