Judul: Gender Determination of Reticulated Python (Malayophython reticulatus) through Probing and Contrast Radiography
Abstrak: The reticulated python, like most snakes which does not exhibit obvious sexual dimorphism; therefore, further steps need to be carried out in order to determine the gender. Gender determination is important for both snake breeders and pet owners as it can help to manage and monitor the breeding activity of the snakes. In this research, probing and contrast radiography is selected among the gender determination methods to compare and determine their consistency and effectiveness. Six reticulated pythons were carried out both probing and contrast radiography twice. The results were compared, and the accuracy of the methods are also determined. Among the snakes, four snakes are found to be male and two snakes are female. The probing results shows 100% accuracy, and the probe inserted for male snake ranged from 1.37-3.60 cm, while for female the probe can could only enter 0.3-0.76 cm. For contrast radiography, the accuracy is 75%. The hemipenis appeared as a white silhouette with a length of 1.13-1.93 cm and the female snake appeared colourless. Based on this research, the results of probing are very accurate and consistent, while contrast radiography there are some false positive and false negative results. Therefore, probing is a much reliable, consistent and efficient method to be applied. Contrast radiography is more suitable on snakes which have a larger body size., Ular sanca kembang, seperti kebanyakan ular lainnya tidak menunjukkan dimorfisme seksual yang jelas; oleh karena itu langkah-langkah lebih lanjut perlu dilakukan untuk menentukan jenis kelaminnya. Penentuan jenis kelamin penting bagi para penangkar ular dan pemilik ular peliharaan karena dapat membantu mengelola dan memantau aktivitas pemuliaan ular-ular mereka. Penelitian ini memilih probing dan radiografi kontras sebagai metode penentuan jenis kelamin untuk dibandingkan dan diketahui konsistensi dan efektifitasnya. Ular sanca kembang sebanyak 6 ekor telah dilakukan probing dan radiografi kontras sebanyak 2 kali. Hasilnya penentuan jenis kelamin kemudian dibandingkan, dan keakuratan dari metode tersebut juga ditentukan. Hasil yang dapat menunjukkan bahwa diantara ular-ular tersebut, 4 ekor ular diketahui berjenis kelamin jantan dan 2 ekor ular berjenis kelamin betina. Hasil pemeriksaan probing menunjukkan akurasi 100%, dan probe yang dimasukkan untuk ular jantan berkisar antara 1,37-3,60 cm, sedangkan untuk ular betina probe hanya dapat masuk 0,36-0,76 cm. Metode radiografi kontras menunjukkan akurasi sebesar 75%. Hemipenis tampak siluet berwarna putih dengan panjang 1,13-1,93 cm dan pada ular betina tidak tampak terwarnai. Berdasarkan penelitian ini, hasil dari probing sangat akurat dan konsisten, sedangkan radiografi kontras ada beberapa hasil positif palsu dan negatif palsu. Oleh karena itu, probing dalam penelitian ini merupakan metode yang lebih dapat diandalkan, konsisten dan efisien untuk diterapkan. Radiografi kontras lebih cocok digunakan pada ular yang memiliki ukuran tubuh yang lebih besar.
Keyword: Contrast Radiography, Gender Determination, Hemipenis, Probing, Reticulated Python

Judul: Penentuan Posisi dan Ukuran Organ Urogenital Ular Sanca Jantan Berdasarkan Sisik dan Citra Ultrasonografi
Abstrak: Penggunaan ultrasonografi untuk mengetahui jenis kelamin dan mencitrakan organ reproduksi ular sanca dapat mendukung manajemen reproduksi yang berkelanjutan.Penelitian ini bertujuan untuk mencitrakan organ urogenital ular sanca jantan menggunakan ultrasonografi. Total individu yang digunakan adalah 14 ekor, yang terdiri dari Malayopython reticulatus (n=6), Python molurus bivittatus (n=3), dan Python regius (n=5). Posisi dan panjang organ urogenital dihitung berdasarkan sisik ventral dan subkaudal. Hasil menunjukkan bahwa posisi dan panjang organ urogenital berada pada nomor dan jumlah sisik ventral yang hampir sama diantara ketiga jenis sanca. Ekogenisitas kelenjar empedu dan scent gland adalah anechoic, sedangkan testis, ginjal, dan hemipenis adalah hypoechoic.
Keyword: Pencitraan ultrasonografi, organ urogenital jantan, sanca, sisik ventral, sisik subkaudal

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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