Judul: Keanekaragaman Repril di Sekitar Kawasan Suaka Margasatwa Nantu Provinsi Gorontalo
Abstrak: Sulawesi island is known for high endemicity of mammals, birds, amphibians and reptiles. Previous amphibians and reptilians survey showed that amphibians and reptiles diversity in this area are still negleted. This research was conducted on June 13th until 27th of Juni 2013 on the eastern part of Nantu Wildlife Reserveand around Bontula village. The objective of this study is to identify the composition of reptile and comparing reptile diversity based on habitats. This study resulted in 19 species reptiles consisting of 54 individual found on seven sampling sites. Three species were Sulawesi endemics consisting of Chrysopelea paradisi celebensis, Rhabdophis callistus, Cyrtodactylus jellesmae and 12 species were classified as Least Concern (LC) based on IUCN redlist.Undisturbed habitat has the highest index of Shannon Wiener diversity (2.11) whilst the lowest index is found on housing area (0.68). Changes in habitat conditions is predicted affect the microclimate of location which caused the majority of reptile unable adapt.
Keyword: reptile, nantu, gorontalo, diversity

Judul: Keanekaragaman Jenis dan Sebaran Spasial Amfibi di Suaka Margasatwa Nantu Gorontalo dan Sekitarnya
Abstrak: Nantu Wildlife Reserve area is one of tropical remnant forest in Sulawesi, a part of Wallaceae bioregion. Nantu Wildlife Reserve was established especially to conserve babirusa, and therefore amphibians data is not available yet. Objectives of the research were to identify types of habitat and species diversity of amphibians in Nantu Wildlife Reserve and its surrounding areas. Data were collected on 14th to 27th of June 2013. Observations were made at seven locations focusing on the east area of the Nantu Wildlife Reserve. Species data were collected using Visual Encountering Survey (VES) combined with Time Search methods. During observation, 4 families were found consisted of 17 species. A map of the spatial distribution of amphibians showed that there was species composition differences among four types of habitats (fields, gardens, low disturbed forest, undisturbed forest). Family of Dicroglossidae was the most common family. There was a clear distinction composition of amphibians between the of amphibians in forest areas with areas that have been cultivated/disturbed by humans.
Keyword: Sulawesi, Nantu Wildlife Reserve, diversity, amphibian

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: