Judul: Keanekaragaman Semut pada Berbagai Tipe Penggunaan Lahan di Jambi
Abstrak: Conversion of tropical forests, mainly to agricultural area is the most important driver of tropical biodiversity loss. As dominant species in lowland forests, ant species diversity is prone to decline sharply due to forest transformation. This research was conducted to investigate the diversity of ants and its role in different land use. Ecological research was conducted in four types of land-use i.e. forest, jungle rubber, oil palm plantation and rubber plantation, located within two landscapes i.e. Bukit Duabelas National Park and Harapan Forest in Jambi, Indonesia. Each type of land use, four plots were selected for ant sampling. Ants were collected using baiting methods, combination between tuna and sugar. Ant diversity in Harapan Forest higher than in TNBD. In total, 66 species of ants belonging to 4 subfamilies and 20 genera were recorded from both area of Bukit Duabelas and Harapan. Surprisingly, the highest number of ant species was found in oil palm plantation. In addition, the compositions of ants based on its role showed differ among land-use types. It indicates that land-use change drive ant species composition.
Keyword: land use, foresty, ant diversity

Judul: Perbandingan Keanekaragaman Semut (Hymenoptera: Formicidae) Pada Empat Tipe Ekosistem yang Berbeda
Abstrak: Deforestation or transformation of forest function to non-forest has been playing a role in the changes of ecosystem and species in it. Insect as one of the living fauna that live in the forest is an interesting aspect to be studied, especially ants. This experiment was conducted in Bungku, Bajubang District , Batanghari Regency, Jambi. Sampling technique using pitfall traps in four ecosystem. The four ecosystem mentioned is secondary forest, oil palm plantations, rubber plantations, and jungle rubber. The results found there were 5 484 individuals of 50 ant morphospecies, 33 genera of 6 subfamily i.e. Formicinae, Myrmicinae, Ponerinae, Dolichodorinae, Pseudomyrmicinae, and Dolichorinae. Secondary forest is an ecosystem that relatively stable with the value of diversity index H '= 2.76, index of richness DMg = 4.96, and index of evenness E = 0.70. The ant communities depend on environment factor of each ecosystem.
Keyword: secondary forest., rubber plantation, oil palm plantation, jungle rubber, Ant diversity

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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