Judul: Infeksi Cacing Saluran Pencernaan pada Orangutan Sumatera (Pongo abelii) dan Orangutan Kalimantan (Pongo pygmaeus) di Taman Margasatwa Ragunan.
Abstrak: Orangutan merupakan hewan endemik Indonesia dan satu-satunya spesies primata besar yang masih ada di Asia. International Union For Conservation of Nature and Natural Resources (IUCN) menyebutkan bahwa orangutan sumatera (Pongo abelii) dan orangutan kalimantan (Pongo pygmaeus) dikategorikan sebagai hewan yang sudah sangat terancam punah. Upaya konservasi ex-situ merupakan hal penting untuk mempertahankan kelestarian jenisnya. Penelitian ini bertujuan untuk mempelajari kejadian infeksi kecacingan saluran pencernaan pada orangutan sumatera dan orangutan kalimantan di Taman Margasatwa Ragunan. Sejumlah total 24 sampel tinja dikumpulkan dari 8 orangutan pada 3 area kandang yang berbeda. Pemeriksaan sampel tinja menggunakan modifikasi teknik McMaster, flotasi sederhana, modifikasi filtrasi-sedimentasi dan kultur feses. Identifikasi jenis cacing ditentukan melalui morfometri telur cacing serta larva infektif strongyle (L3) secara mikroskopik. Hasil penelitian menunjukkan bahwa persentase kecacingan pada delapan orangutan adalah 100%, yaitu strongyle 37.5% dan Strongiloides 100%. Derajat infeksi tertinggi adalah jenis Strongyloides ditemukan pada orangutan yang berumur sangat muda, sedangkan derajat infeksi strongyle relatif lebih rendah. Hasil identifikasi larva ditemukan L3 Trichostrongylus spp.
Keyword: Cacing saluran pencernaan, Pongo abelii, Pongo pygmaeus, Taman Margasatwa

Judul: Infestasi Cacing pada Orangutan Kalimantan (Pongo pygmaeus) dan Orangutan Sumatera (Pongo abelii) di Taman Margasatwa Ragunan
Abstrak: Bornean and Sumatran Orangutans are endemic faunas which are classified by CITES in Appendix 1, list that contains species of faunas which are threatened for commercial international trading. Orangutans are included as endangered animals as the result of the decrease of habitat and illegal hunting so it needs conservation effort. The purpose of this research are to study the species of gastrointestinal parasite (worms) in orangutans, such as Strongiloides, Ancylostoma and Trichostrongiloid that could be transfered within the population and transmitted from orangutans to human, also to study the degree of worms infestation in orangutans. Fresh fecal sample was collected in Ragunan Zoo, and put into buffer formaline 10%. Fecal sample was examined with native method,modified filtration-sedimentation method and calculating TTGT (egg in each gram feces) by using Mc.Master method. Fecal sampel was examined natively and found several worm egg type, those are ascarid, strongiloides, trichostrongiloid and trichuris. The sedimentation examination was done by using sugar-salt liquid and filtered levelly for detain trematoda eggs, however all sampels not showed positive result. Based on the result of fecal examination of orangutans in Ragunan Zoo showed that Bornean and Sumatran Orangutan were positively infected by Nematoda worms. Orangutan at Ragunan Zoo were infected by 4 worm eggs type those are strongiloides type, ascarid type, strongiloid type and trichurid type. Bornean orangutan and Sumatran orangutan were infected by ascarid worm egg type and strongiloides worm egg type with low-moderate risk infection. The strongiloid worm egg type infected the orangutan at Ragunan Zoo with low risk infection meanwhile the trichurid worm egg type founded only at one animal.
Keyword: fecal sample., Helminthiasis, Orangutan

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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