Judul: Daily Activities and Welfare Rate Agile Gibbon (Hylobates agilis) at Schmutzer Primates Center, Ragunan Zoo
Abstrak: Keberadaan ungko sebagai salah satu jenis satwa yang dilindungi semakin menurun populasinya akibat perburuan dan hilangnya habitat. Salah satu upaya konservasi ungko dilakukan secara ex-situ di kebun binatang. Penelitian ini bertujuan untuk mengidentifikasi aktivitas harian, mengidentifikasi manajemen pemeliharaan dan mengukur tingkat kesejahteraan ungko. Metode yang digunakan meliputi observasi langsung dan wawancara kepada pengelola serta studi literatur. Hasil penelitian menunjukkan aktivitas yang paling banyak dilakukan oleh ungko jantan yaitu istirahat sebesar 29,33%, bergerak 25,33%, menelisik 20%, makan 14% dan main 11,33%. Sedangkan ungko betina lebih banyak melakukan aktivitas istirahat dengan persentase sebesar 31,69% yang diikuti dengan aktivitas menelisik 29,23%, bergerak 21,31%, makan 11,20% dan bermain 6,56%. Ukuran kandang ungko yang ada di PPS telah memenuhi standar NSW Agriculture sehingga ungko dapat bebas bergerak. Pakan yang diberikan telah memenuhi kebutuhan ungko. Pengelolaan kesejahteraan ungko di PPS dilakukan dengan sangat baik. Pencapaian implementasi kesejahteraan ungko di PPS memiliki nilai sebesar 81,50 yang termasuk dalam kategori sangat baik.
Keyword: agile gibbon, daily activities, maintenance management, welfare rate

Judul: Assessment of the Readiness on Release of Javan Gibbon (Hylobates moloch) in Javan Gibbon Center, Mount Gede Pangrango National Park
Abstrak: Owa jawa merupakan primata dilindungi yang masih diperdagangkan. Salah satu upaya konservasi owa jawa yaitu rehabilitasi sebelum dikembalikan ke alam liar. Penilaian kesiapan pelepasliaran merupakan salah satu cara untuk memastikan bahwa owa jawa dapat bertahan hidup setelah dilepasliarkan. Penelitian dilaksanakan di Javan Gibbon Center untuk menduga alokasi waktu aktivitas harian owa jawa pada masa rehabilitasi; dan membandingkan pola perilaku dan alokasi waktu aktivitas harian antara owa jawa masa rehabilitasi dengan owa jawa liar. Penelitian dilakukan pada bulan April selama 11 hari dengan mengamati aktivitas dua pasang owa jawa di kandang. Data tersebut kemudian dibandingkan dengan aktivitas owa jawa liar dan dimasukkan ke dalam tabel penilaian kesiapan pelepasliaran individu owa jawa. Tingkat kesamaan aktivitas harian owa jawa rehabilitan dengan owa jawa liar bervariasi, mulai dari 34,16-90,96% dengan tingkat kesamaan tertinggi pada aktivitas bergerak dan terendah pada aktivitas seksual. Pola perilaku bimodal tidak berlaku pada owa jawa di kandang rehabilitasi. Objek penelitian yang diamati masuk ke dalam kategori siap untuk dilepasliarkan., Javan gibbons (Hylobates moloch) are protected primates that are still being traded. One of the conservation efforts of the javan gibbon is rehabilitation before being returned to the wild. Assessment of release readiness is one way to ensure that the javan gibbon can survive after being released into the wild. The study was conducted at the Javan Gibbon Center to estimate the time allocation for the daily activities of the javan gibbons during the rehabilitation period; and comparing behavior patterns and time allocation of daily activities between Javan gibbons during rehabilitation and wild javan gibbons. The study was conducted in April for 11 days by observing the activity of two pairs of javan gibbons in a cage. These data were then compared with the activity of wild javan gibbons and entered into a table for assessing individual release readiness of javan gibbons. The level of similarity in the daily activities of the rehabilitated Javanese gibbon with the liar Javan gibbon varied, ranging from 34.16-90.96% with the highest level of similarity in moving activities and the lowest in sexual activity. Bimodal behavior patterns did not apply to Javan gibbons in rehabilitation cages. The observed object of research is categorized as ready to be released into the wild.
Keyword: daily activity, javan gibbon, Javan Gibbon Center, rehabilitation

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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