Judul: Trade and Harvest Characteristics of Asian Bockadam (Cerberus schneiderii) from West Java
Abstrak: Salah satu ular dari famili homalopsidae yaitu ular asin (Cerberus schneiderii) banyak diperdagangkan dari Indonesia. Namun, ular tersebut hanya sedikit diteliti di seluruh wilayah sebarannya yang luas. Data perdagangan dan biologis dari ular asin di Indonesia tidak terdokumentasi dengan baik. Berdasarkan data perdagangan dan pembedahan 3.382 ular yang dibawa ke fasilitas pemrosesan di Cirebon, Jawa Barat, kami mendokumentasikan volume dan karakteristik perdagangan, juga aspek biologi dari ular air yang memiliki habitat di daerah pesisir ini. Panen komersial dilakukan pada individu dewasa jantan dan betina. 43 Negara diketahui mengimpor ular asin dalam berbagai bentuk (kulit dan turunannya, daging, hewan hidup, dan spesimen) dari 1984-2020. Singapura menjadi negara terbesar yang mengimpor jenis ini dari Indonesia (>60%) setara dengan 2.176.477 individu. Ular asin didapatkan dari alam (W>60%) di sebagian pesisir utara Jawa Barat, dan Jawa Tengah. Ular asin diperoleh dari individu, dan kelompok pemburu ular. Ular asin dihargai 6000-12000 rupiah per kilogram. Ular asin yang diekspor sebagian besar berupa kulit dan daging. Berdasarkan data perdagangan ular asin tersebut, pejantan menunjukkan pembesaran testis di akhir tahun (Agustus-November), akan tetapi betina yang produktif dan tidak produktif dijumpai di sepanjang tahun. Betina dapat memiliki 3-45 anakan dalam satu waktu, lebih banyak pada betina dengan ukuran lebih besar. Jenis ini diketahui memiliki kemampuan pematangan awal dalam fase reproduksinya, serta beranak (ovovivipar) sepanjang tahun. Tekanan terhadap populasi ular asin akibat adanya panenan komersial dapat ditahan dengan membatasi panen di beberapa lokasi dan/atau beberapa waktu dalam setahun, sehingga dapat mengalihkan dampak panen dari kelompok kritis seperti betina dewasa., One of homalopsid snake, Asian bockadams (Cerberus schneiderii) is heavily traded from Indonesia. However, the snake has attracted relatively little study across their wide geographic range. Trade and biological data from Asian Bockadams in Indonesia are not well documented. Based on trade data and dissection of 3,382 snakes brought to a processing facility in Cirebon, West Java, we document the volume and characteristics of the trade, as well as the biology of the water snakes that have a habitat in the coastal area. 43 Countries are known to import asian bockadam in various forms (skins and derivatives, meat, live animals, and specimens) from 1984-2020. Singapore is the largest country that imports this species from Indonesia (> 60%), equivalent to 2,176,477 individuals. Asian bockadam are obtained mostly from nature (W> 60%), in parts of the north coast of West Java and Central Java. Asian bockadam are obtained from individuals and groups of snake hunters. Asian bockadam are valued at 6000-12000 rupiah per kilogram. Skin and meat are the most traded forms for asian bockadam. Among all of the snake that harvested from West Java, males showed testicular enlargement late in the year (August-November), but both reproductive and non-reproductive females were found year-round. Litters were large (3 to 45 offspring), especially in larger females. The commercial harvest falls mainly on adult snakes of both sexes. Life-history traits such as early maturation and frequent production of large litters render this species resilient to commercial harvesting. The data obtained can be used as a scientific basis in Asian Bockadams conservation management.
Keyword: Berkelanjutan, Homalopsidae, Konservasi, Perdagangan

Judul: Tata Niaga, Parameter Demografi, Morfometri, Panenan dan Karakteristik Habitat Ular Sendok Naja sputatrix (Boie, 1827) di Provinis Jawa Timur.
Abstrak: Spitting cobra (Naja sputatrix Boie 1827) has been harvested and traded in local and international market, yet there was still no suficient data concerning its population and habitat. The main purposes of this research was to analyze the trading system, demographic parameters, morphometry and habitat characteristics of spitting cobra in East Java Province. The actors involved in the trading systems functioning as harvesters, collector, sub agen, agents, and also domestic users which likely had no allegiance between them and very much influenced by the market. Morphometrics measurement of the speciments, showed that male snakes had a longer bodysize compare to females, SVL were 999,2 cm and 998,9 cm respectively,which 81,90% of total harvested speciments were adult spitting cobras. The females dominated the harvested population of all trade actors, up to 90,54%, this might be an effect of harvesting pattern where the harvesters conducted catching outside the nests. Such pattern would be a threat for the population of the snake. Spitting cobras had no habitat preference and could easily adapted with different kinds of environment.
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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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