Judul: Potensi Pakan dan Perilaku Makan Lutung Budeng(Trachypithecus auratus) di Cagar Alam Dungus Iwul, Jawa Barat
Abstrak: Ebony leaf monkey (Trachypithecus auratus) is an endemic primate to Java Island, Lombok Island, and Bali Island. According to IUCN Red List of Threatened Species ver 3.1, conservation status of ebony leaf monkey is vulnerable and listed in Appendix II CITES. One of the things that need to be considered to preserve ebony leaf monkey’s population is maintain and increase the availability and abundance of its feed because feed is one of the basic needs of animals. The objectives of this research are to identify feed plant species, measured the abundance and distribution of feed plant species, estimate food palatability level, and identify ebony leaf monkey’s feeding behaviour. Data were analyzed using Chi-square test. There are 29 trees species of ebony leaf monkey’s feed. One of the feed is Orania sylvicola, which has the highest abundance. Distribution of ebony leaf monkey’s feed is random, only one species uniformly distributed which is Orania sylvicola. The most palatable food of ebony leaf monkey is Barringtonia racemosa. The position which most frequently performed when eating is sitting position.
Keyword: palatability, feeding behaviour, feed, ebony leaf monkey

Judul: Feeding Behavior and Feed Nutritional Content of Javan Langur (Trachypithecus auratus) at Leuweung Sancang Nature Reserve
Abstrak: Keberadaan pakan alami lutung budeng sangat bergantung pada ketersediaan habitatnya di alam yang nantinya akan berpengaruh terhadap keberadaan populasi lutung budeng di habitat aslinya. Tujuan penelitian ini adalah mengidentifikasi jenis tumbuhan pakan lutung budeng, menganalisis kandungan nutrisi pakan lutung budeng, dan mengidentifikasi perilaku makan lutung budeng di CA Leuweung Sancang. Metode yang digunakan yaitu Ad-libitum sampling dan Scan sampling untuk mencatat jenis tumbuhan pakan dan perilaku makan, serta analisis proksimat, kalsium, fosfor, dan gross energy untuk mengetahui kandungan nutrisi tumbuhan pakan lutung budeng. Jenis tumbuhan pakan lutung budeng di CA Leuweung Sancang yaitu sebanyak 47 jenis dari 30 famili. Persentase perilaku makan yaitu sebesar 40,70% dari keseluruhan aktivitas hariannya. Kadar air dan kandungan bahan ekstrak tanpa nitrogen (BETN) tertinggi terdapat pada jenis Terminalia catappa. Kadar abu, kandungan fosfor, dan kandungan energi tertinggi terdapat pada jenis Averrhoa bilimbi. Kandungan protein kasar tertinggi pada jenis Pongamia pinnata. Kandungan serat kasar dan lemak kasar tertinggi pada jenis Ardisia humilis. Kandungan kalsium tertinggi pada jenis Cananga odorata., The availability of natural feed for Javan langur (Trachypithecus auratus E. Geoffroy Saint-Hilaire, 1812) is very dependent on the existence of its habitat in nature which will later affect the persistence of the Javan langur population in its natural habitat. This study aims to identify the feed plants, analyse the nutritional content of feed plants, and identify the feeding behaviour of Javan langur at Leuweung Sancang Nature Reserve. The methods used were Ad-libitum and Scan sampling which recorded the feed plant species and feeding behaviour, and then proximate analysis also calcium, phosphorus, and gross energy to determine the nutritional content of feed plants. There are 47 type of feed plants in Leuweung Sancang Nature Reserve from 30 families. Feeding behaviour composed 40.70% of all daily activities. The results of the nutrient analysis showed that the highest water and extract material without nitrogen was attributed to Terminalia catappa. The highest ash, phosphorus, and gross energy content values was obtained in Averrhoa bilimbi. The highest crude protein content value was obtained in Pongamia pinnata. The highest crude fibre and crude fat content value was obtained in Ardisia humilis. The highest calcium content value was obtained in Cananga odorata.
Keyword: feeding behavior, feed plants, Javan langur, nutritional content

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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