Judul: Manajemen Pakan Orangutan Sumatera (Pongo abelii Lesson, 1827) di Pusat Reintroduksi Orangutan Sumatera (PROS) Provinsi Jambi
Abstrak: One effort to conserve orangutans population in their natural habitat was by reintroduction. In reintroduction stage, orangutans temporarily live in socialization cage and feed as necessary for introduction to ensure their survival in the wild. Success of orangutan survival in nature could be reached through good management, including orangutan’s food management. Research is needed to identify food and feeding management in a reintroduction activity, to study the feeding duration of orangutan based on feeding frequency, and to study feeding habit of orangutan in socialization cage. Data was collected in June to September 2011 in Sumatran Orangutan Reintroduction Center (SORC) located in two stations: SORC Sungai Pengian Station (Tebo District, Jambi Province) and Open Orangutan Sanctuary (OOS) Danau Alo Station (West Tanjung Jabung District, Jambi Province). Data collection was including primary and secondary data that consist of feeding management, feeding duration, orangutan’s feeding habit, cage management and orangutan’s health management. Focal Animal Sampling methods was used to know orangutan’s feeding habit. Data was analyzed descriptively and qualitative. There were 6 orangutans used as samples, representing different sexes and age structures. Orangutan’s food management in socialization cage was categorized based on food type, feeding time, food preparation, and feed presentation. There were 4 types of food: main food, enrichment food, natural food, and additional food. The main food was given 5 times a day. Food type and main feeding time was arranged based on food management by considering diet of orangutan’s food. The fastest average feeding time was by orangutan named Frangkie (sub adult, female; averaging 3 minutes 52 seconds), while the longest was in orangutan named Mirriam (juvenile, female; 20 minutes 12 seconds). Management implementation was supported by reintroduction to natural habitat, Mobile Educational Unit, Wildlife Protection Unit and Community Development. Feeding duration of orangutan was affected by food type, method of food provision, method of feed preparation and feeding habit of orangutan. Feeding management in reintroduction centre was needed to increase enrichment food and natural food. In addition, further research about proximate analysis is needed, as well as changing food container
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Judul: Behavior and Food of Reintroduced Bornean Orangutan (Pongo pygmaeus wurmbii) at Feeding Site and Forest Area in Lamandau Wildlife Sanctuary
Abstrak: Orangutan Kalimantan (Pongo pygameus wurmbii) adalah primata besar Asia berstatus ‘Dalam Bahaya Kritis’. Reintroduksi dilakukan untuk menekan penurunan populasi mereka di alam. Penelitian yang dilaksanakan pada bulan Februari-April 2021 di Suaka Margasatwa Lamandau bertujuan mengidentifikasi perbedaan perilaku di feeding site dan hutan alam, komposisi dan preferensi pakan tambahan dan alami orangutan kalimantan reintroduksi. Sebanyak empat kategori dari enam individu berbeda telah teramati selama 219 jam. Kedatangan orangutan ke feeding site secara nyata (P = 1 > α = 0,05) tidak dipengaruhi oleh pemberian pakan tambahan, sehingga aktivitas harian di hutan alamlebih besar. Aktvitas harian tertinggi yang dilakukan berturut-turut adalah makan, istirahat, dan berpindah. Komposisi pakan tambahan yang diberikan dalam bentuk buah berupa pisang (Musa spp.) dan pepaya (Carica papaya). Komposisi pakan alami tertinggi orangutan dari jenis-jenis tumbuhan adalah buah (51%), daun muda 25%, dan bagian tumbuhan lainnya (15%). Jenis pakan yang termasuk kategori sangat disukai adalah papung (Sandoricum emarginatum) sebesar 0,73, dan kumpang darah (Knema conferta) sebesar 0,66. Kategori lainnya yaitu sembilan jenis tumbuhan ‘Disukai’, tujuh jenis tumbuhan ‘Kurang Disukai’, 16 jenis tumbuhan ‘Tidak Disukai’, dan delapan jenis tumbuhan ‘Tidak Dikategorikan’., The Bornean orangutan (Pongo pygameus wurmbii) is a 'Critically Endangered' large Asian primate. Reintroduction had been implementing to suppress their population decline in the wild. The research was conducted in February-April 2021 at Lamandau Nature Sanctuary, aimed to identify differences in behaviour at the feeding site and natural forest, composition and preferences for additional and nature feed for Bornean orangutan reintroduced. A total of six different individuals with four categories had observed for 219 hours. The arrival of orangutans to the feeding site significantly (P = 1 > = 0,05) was not affected by additional feeding, so daily activities in natural forestswere longer. The highest daily activities performed consecutively were eating, resting, and moving. The composition of the supplementary feed had given in the form of fruit in the form of banana (Musa spp.) and papaya (Carica papaya). The highest composition of natural food for orangutans from plant species is fruit (51%), young leaves 25%, and other plant parts (15%). Types of feed which included in the category of 'Highly Favoured' were papung (Sandoricum ermarginatum) of 0,73 and kumpang darah (Knema conferta) of 0,66. Other categories are nine plant species 'Preferred', seven plant species 'Less Like', 16 plant species 'Disliked', and eight plant species 'Not Categorized'.
Keyword: Bornean orangutan, daily activities, feed preferences, feeding site, Lamandau nature sanctuary, reintroduction

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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