Judul: The Diversity of Soil Surface Insects in Three Types Land Use in Sintang District, West Kalimantan
Abstrak: Serangga tanah merupakan organisme yang memiliki peran penting dalam proses penguraian bahan organik tanah, indikator kesuburan tanah dan menjaga keseimbangan ekosistem. Penelitian ini bertujuan untuk mengetahui keane- karagaman dan kelimpahan serangga permukaan tanah pada tiga tipe lahan karet yaitu perkebunan karet, agroforestri karet, serta hutan sekunder dan mengetahui serangga yang menyerang batang karet di Kabupaten Sintang Kalimantan Barat. Metode penelitian yang digunakan adalah observasi lapang, pengambilan sampel dengan pitfall trap dan pengukuran kondisi lingkungan, identifikasi serta analisis data pada tiga tipe lahan karet. Hasil penelitian menunjukkan bahwa ditemukan sebanyak 649 individu yang terbagi menjadi 8 ordo 11 famili 14 jenis. Kelimpahan tertinggi terdapat pada tipe lahan agroforestri karet sedangkan keanekaragaman tertinggi terdapat pada hutan sekunder. Jenis serangga ditemukan menyerang batang pohon karet baik yang mati maupun hidup adalah Coptotermes curvignathus di lahan agroforestri karet dan Reticulitermes flavipes di lahan hutan sekunder dan perkebunan karet. Kata kunci: biodiversitas, kerusakan, pitfall trap, serangga tanah, tanaman karet, Soil insects are organisms that have an important role in the process of decomposing soil organic matter, indicators of soil fertility, and maintaining ecosystem balance. This study aims to determine the diversity and abundance of soil surface insects on three types of rubber land, namely rubber plantations, rubber agroforestry, and secondary forests and the alarm that attacks rubber stems in Sintang District, West Kalimantan. The research method used was field observation, sampling with pitfall traps and measurement of environmental conditions, identification, and data analysis on three types of rubber land. The results showed that 649 individuals were found which were divided into 8 orders of 11 families of 14 species. The highest abundance was found in rubber agroforestry land types, the highest biodiversity was in secondary forest. The types of insects found attacking the rubber tree trunks, both dead and alive, were Coptotermes curvignathus in rubber agroforestry and Reticulitermes flavipes in secondary forest and rubber plantations. Keywords: biodiversity, damage, ground insects, pitfall trap, rubber plant
Keyword: biodiversity, damage, ground insects, pitfall trap, rubber plant

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: 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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