Judul: Perilaku Cacing Tanah (Perionyx excavatus) pada Media Kotoran Sapi: Langkah Awal Domestikasi
Abstrak: The most common found earth worm in Indonesia is Perionyx excavatus. This worm has weight and body length larger than other types of earthworms. This study aimed to observe the behavior of P. excavatus on cow dung media as a first step to facilitate the process of domestication of cultivation. The experimental design used in this research was Completely Randomized Design. Observations were conducted by observing the daily behavior of P. excavatus for 24 hours, by observing the daily behavior P. excavatus were maintained in four media, 100% cow dung, 50% banana midrib : 50% cow dung, 90% banana midrib : 10% cow dung, and 100% soil. Each media were consisted of 3 replication. Data were analyzed using ANOVA. Based on observations, P. excavatus performed 4 main activities, which were movement, resting, eating and mating. The best media to supports the activities of P.excavatus based on the percentage of movement activity and eating was 50% banana midrib : 50% cow dung. To support the production of cocoon, the best media 90% banana midrib : 10% cow dung, and the best media to support the juvenile production was 100% cow dung based on the value of the coefficient of variance were 71.18%, and 10, 23%.
Keyword: Bogor Agricultural University (IPB), Perionyx excavatus, daily behavior, local earthworms

Judul: Observasi Perilaku Cacing Tanah Metaphire sp. Sebagai Upaya Awal Domestikasi
Abstrak: Cacing tanah memiliki banyak peran dan manfaat, baik sebagai agen pengolah tanah, memperbaiki kesuburan tanah, maupun sebagai bahan utama berbagai produk (misalnya : obat, kosmetik), karenanya cacing tanah banyak dibudidayakan. cacing lokal Indonesia, Metaphire sp. memiliki biomassa yang besar,namun jenis cacing ini belum banyak diteliti dan dibudidayakan. Oleh karena itu, perlu upaya domestikasinya sebagai langkah awal untuk memudahkan budidaya. Penelitian ini bertujuan untuk mempelajari pola perilaku harian cacing tanah Metaphire sp. dewasa pada tingkat individu. Penelitian ini dilakukan dengan pengumpulan dan pemeliharaan stok cacing. Kemudian diamati perilaku Metaphire sp. di permukaan tanah (di dalam kandang pemeliharaan) dan perilaku di dalam tanah (dengan menggunakan terarium kaca). Masing-masing dilakukan selama 7 hari pengamatan. Setiap perilaku cacing diamati dan dicatat lalu dimasukkan ke dalam tabel ethogram. Selain itu, diamati juga panjang lorong galian dan pola galiannya. Hasil penelitian ini menunjukkan bahwa perilaku Metaphire sp. paling dominan dilakukan di siang hari yaitu perilaku istirahat (inaktif) dan lebih banyak melakukan aktivitasnya di dalam tanah. Metaphire sp. muncul ke permukaan tanah lebih banyak dilakukan di malam hari. Puncak aktivitas Metaphire sp. nampak berlangsung pada waktu malam dimulai dari 18.00-23.00. Kata kunci : Metaphire, domestikasi, perilaku, Earthworms plays many roles, comprising processing soil, improving soil fertility, and being an ingredient in various products (e.g. medicine, cosmetics). Therefore, earthworms are widely cultivated. The Indonesian worm, Metaphire sp. constitutes a large biomass, but it has not been widely researched and cultivated. Domestication is a necessary first step in facilitating cultivation and husbandry. This study aims to determine the natural daily behavioral pattern of adult Metaphire sp. earthworms at the individual level. This research was conducted by collecting and keeping a stock of worms. Then, we observed the natural behavior of Metaphire sp. on and under the surface of the soil (through a glass terrarium) for 7 days each. Observed parameters for each behavior were recorded in the ethogram table. We also sketched and recorded the length of the excavated tunnel. During the day, Metaphire sp. showed predominantly resting or inactive behavior and mostly activities were done under the soil surface. Metaphire sp. comes to the ground mostly at night. Based on these results, the peak activity of Metaphire sp. can be stated that it takes place at night starting from 18.00-23.00. In the night, Metaphire sp. appeared and did most activites on the surface. We conclude that Metaphire sp. are most active at night, precisely from 6 PM to 11 PM. Keywords : Metaphire, domestication, behavior
Keyword: Metaphire, domestication, behavior

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.
Keyword: