Judul: Produktivitas Burung Murai Batu (Copsychus malabaricus) Asal Medan di Penangkaran
Abstrak: Burung murai batu (Copsychus malabaricus) merupakan salah satu jenis burung yang sangat digemari oleh para penggemar burung. Populasi murai batu di alam sudah mulai langka walaupun penangkaran terhadap murai batu sangat bagus untuk mempertahankan populasi. Tujuan penelitian ini adalah untuk mengetahui daya produksi, fertilitas, daya tetas, dan mortalitas burung murai batu asal Medan (Copsychus malabaricus) di penangkaran. Penelitian dilakukan pada bulan April sampai Mei 2018 di penangkaran KABF di Bogor. Penelitian ini menggunakan 7 pasang induk burung murai batu asal Medan. Parameter yang diukur dalam penelitian ini adalah produksi telur, fertilitas, daya tetas, dan mortalitas. Hasil penelitian menunjukan bahwa produktivitas telur berkisar 2-4 butir tiap 1 kali periode bertelur. Fertilitas berkisar 29.2%-66.7%, daya tetas berkisar 86.67%-100% dan mortilitas sebesar 32.78% pada anak burung murai batu asal Medan di penangkaran.
Keyword: daya produksi, daya tetas, fertilitas, mortalitas, murai batu

Judul: Reproductive Pattern and Determinant Factor of Productivity White-Rumped Shamas (Copsychus malabaricus) at Bowo Bird Farm Bogor
Abstrak: Murai batu (Copsychus malabaricus) merupakan salah satu burung kicau yang digemari oleh masyarakat. Penelitian ini bertujuan mengidentifikasi manajemen indukan, pola reproduksi, tingkat produktivitas, dan faktor penentu produktivitas murai batu di Bowo Bird Farm. Data dikumpulkan melalui observasi lapang, wawancara, dan penelusuran dokumen. Hasil penelitian menunjukkan bahwa rata-rata umur dewasa kelamin murai batu betina 8 ± 0 bulan, sedangkan jantan 12 ± 0 bulan; jumlah telur per sarang 2,80 ± 0,41 butir; lama masa pengeraman telur 14 ± 0 hari; umur sapih anakan pada tahun 2014-2019 berumur 7 ± 0 hari (1 minggu), sedangkan tahun 2020 berumur 21,67 ± 0,57 (3 minggu); jarak bertelur kembali pada umur sapih anakan 1 minggu 31,17 ± 2,60 hari, sedangkan pada umur sapih anakan 3 minggu 40,34 ± 1,53 hari; lama umur produktif murai batu betina 4 tahun, sedangkan jantan 20 tahun. Tingkat produktivitas murai batu tergolong sedang dengan persentase induk produktif 65,77%, daya tetas telur 63,50%, dan persentase kematian anak 31,87%. Faktor penentu produktivitas berdasarkan regresi stepwise yaitu frekuensi bertelur induk, jumlah telur per sarang, dan jarak waktu bertelur kembali, sedangkan berdasarkan metode PCA yaitu PC I (jarak waktu bertelur kembali, frekuensi bertelur induk, dan umur induk betina) dan PC II (jumlah telur per sarang dan jumlah konsumsi pakan)., White-rumped shama (Copsychus malabaricus) is one of the chirping birds that are widely favored. This research aims to identify broodstock management, reproductive pattern, productivity levels, and determinant factor of productivity white-rumped shamas at Bowo Bird Farm. Data is collected through field observations, interviews, and relevant document analysis. The result of the research showed that average age of puberty female is 8 ± 0 months, while male 12 ± 0 months; clutch size is 2,80 ± 0,41 eggs; hatching period is 14 ± 0 days; age of weaned juveniles in 2014-2019 is 7 ± 0 days (1 week old), while in 2020 is 21,67 ± 0,57 days (3 weeks old); egg production cycle for 1 week weaned juveniles is 31,17 ± 2,60 days, while for 3 weeks weaned juveniles is 40,34 ± 1,53 days; productive lifespan of female is 4 years, while male is 20 years. The productivity level is classified as moderate with percentage of productive broodstock 65,77%, egg hatchability 63,50%, and juvenile mortality 31,87%. The determinant factors of productivity based on the stepwise regression were broodstock laying egg frequency, clutch size, and egg production cycle, while based on the PCA method were PC I (egg production cycle, broodstock egg laying frequency, and age of female broodstock) and PC II (clutch size and amount of feed consumed).
Keyword: murai batu, penangkaran, pola reproduksi, produktivitas, captivity, productivity, reproductive pattern, white-rumped shamas

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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