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: Studi Perilaku Makan dan Palatabilitas Rekrekan (Presbytis fredericae Sody, 1930) di Kawasan Hutan dan Perkebunan Karet Desa Gutomo Kabupaten Pekalongan Provinsi Jawa Tengah
Abstrak: Javan Fuscous Langurs is one of the endemic primate in Java island and was declared as protected animal by law in Indonesia and also IUCN define it as a species with category data defficience. In primate it self, the phylogenetic and ecological difference influence to feeding behavior and it makes every species with different habitat have different feeding behavior. Then, it is important to us to have data and information about their feeding behavior. The purpose of this research are to get information about feeding ecology of Javan Fuscous Langurs that consist of feeding behavior, composition and diversity of the foods, foods preference and also some factors that influence feeding behavior. The result from this research expected can consider as one of the substance for doing good habitat management for Javan Fuscous Langurs. Data collection were done with period 6 months in the forest area and rubber plantation dusun Sidoguno. The equipments are map, camera, GPS, binocular, stopwatch, compass, tallysheet, clinometers, rope, software Arcview 3.2 and stationery. Whereas, the objects are 2 groups of Javan Fuscous Langurs with different type for each other. Group A has type 1 male-multi female with composition 1 adult male, 4 adult female, 1 subadult female, 1 juvenille female and 2 infants. Group B has type all male with composition 2 adult male, 2 sub adult male, and 1 juvenille male. The method for observed used scan sampling and for record data used continous recording method and the data will be analyzed by descriptive statistic and on graphs . Daily activity of Javan Fuscous Langurs consist of resting (57,66%), feeding (29,33%), moving (11,51%), social activity (0,93%) and calling (0,43%). This 2 groups of Javan Fuscous Langurs has different homerange, group A has homerange 54,55 ha and group B has smaller homerange than group A (48,16 Ha) with overlap between two of them around 2,49 Ha. But then, group B has daily range more longer than group A, it around 694-1269 m where daily range of Group A only 576-1146 m. in the feeding behavior, group A more often used sit posture and used space in the tree canopy between top-middle with height around 6-10 m, group B more often used sit posture in space between middle-edge with height around 0-5 m. group A feed 56 species from 34 family of plants as their foods and group B feed 45 species from 29 family with variation foods composition such as young leaves, seeds and fruits. Plant species that have great contribute as foods for the two species is Hevea brasiliensis. Chisocheton divergens become species with the highest ratio selection in the group A and Pangium edule. for the group B. Two groups have different vegetation structure and composition. In the home range of group A were identified 170 trees/ha with lbds 27,51 m2/ha and the diversity index for tree level is 3,21. In the homerange of the Group B were identified 301 trees/ha with lbds 20,62 m2/ha and the diversity index for tree level is 1,24. Conclusions from this research are feeding behavior of Javan Fuscous Langurs is
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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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