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: Aktivitas Makan dan Preferensi Pakan Orangutan Sumatera (Pongo abelii Lesson, 1827) di Resort Bukit Lawang, Taman Nasional Gunung Leuser
Abstrak: Orangutans are one of the primates which known as great apes and it is endemic in the island of Sumatera. This research was done at Sumatran Orangutan Viewing Center in Bukit Lawang. The aim of this study is to know the feed preferences and feeding activities of sumatran orangutan. The methods used in this study are Focal Animal Sampling which is done by following one individual orangutans during a certain period and single swath method in three different plots. The observations showed that orangutan’s feeding activity are smaller than resting and moving activity. There are 47 kinds of food that was eaten by orangutans. This food consisting of 5 habitus that is a tree, liana, herbaceous, clumps, and epiphyte. The part of plants that mostly consumed are leaves as much as 48,61%, fruit 27,49%, others (termites, ants, insects, soil) 12,75%, bark 7,17%, and flower 3,98%. Based on the feed preferences, the preferred type of feed are sibolangit (Garcinia lateriflora), rattan (Calamus sp.), and rambung (Vernonia arborea).
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Judul: Penggunaan Metode Homotopi untuk Menyelesaikan Persamaan KdV (Korteweg-de Vries)
Abstrak: Natural phenomena can be explained using nonlinear mathematical models. In this paper, we studied the solution of KdV equation using the Homotopy method. The KdV equation is used for describing both surface and internal waves. One of the solutions is called a solitary wave. The use of homotopy method to solve the KdV equation required a nonlinear operator which was determined by the nonlinear form of the KdV equation itself. Based on this operator, a recursive formula was obtained to get a sequence of the KdV solution. The higher the sequence order of the sequence used, the closer to the exact solution of the KdV equation.
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