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: Diversity and Abundance of Two Canopy Beetle Families in Four Landuse Types at Harapan Rainforest, Jambi.
Abstrak: Pembukaan lahan hutan menjadi kawasan perkebunan menyebabkan penurunan berbagai spesies flora dan fauna di wilayah tropis, tidak terkecuali di Indonesia. Salah satu yang terdampak besar adalah penurunan kelimpahan dan kekayaan spesies serangga, diantaranya kumbang Elateridae dan Staphylinidae. Penelitian ini bertujuan memelajari pengaruh perbedaan waktu dan perubahan tata guna lahan terhadap keanekaragaman dan komposisi kumbang Elateridae dan Staphylinidae di beberapa wilayah Hutan Harapan, Jambi, Sumatra. Pengambilan sampel dilakukan dengan menggunakan metode pengasapan kanopi pohon pada empat tipe penggunaan lahan: hutan, hutan karet, perkebunan karet, dan perkebunan kelapa sawit. Pada masing-masing tipe penggunaan lahan, terdapat empat plot inti dan pada setiap plot terdapat tiga subplot sebagai ulangan. Serangga dikumpulkan dalam delapan perangkap (ukuran 1 m × 1 m) yang dipasang di bawah tajuk tanaman sebelum proses pengasapan. Sampel yang telah dikumpulkan, disortir, dan diidentifikasi. Kumbang Elateridae ditemukan sebanyak 527 individu yang terdiri dari 3 subfamili, 10 genus, dan 18 morfospesies, sedangkan kumbang Staphylinidae ditemukan sebanyak 694 individu yang terdiri dari 11 subfamili, 16 genus, dan 47 morfospesies. Perbedaan tipe penggunaan lahan mempengaruhi kekayaan spesies kumbang Elateridae dan Staphylinidae, tetapi perbedaan tipe penggunaan lahan tidak mempengaruhi kelimpahan spesies kumbang Elateridae dan Staphylinidae., Transformation of forest land into plantation areas has resulted in the decline of various species of flora and fauna in the tropics, including Indonesia. One of the major impacts is the decrease in the abundance and richness of insect species, including Elateridae and Staphylinidae beetles. This reserach was aimed to study the effect of time and landuse change toward the diversity and abundance of Elateridae and Staphylinidae beetles in Hutan Harapan landscape in Jambi, Sumatra. Sampling was carried out using the tree canopy fogging method on four types of land use: forest, jungle rubber, rubber plantation, and oil palm plantation. In each land use type, there are four core plots and in each core plot, there are three subplots. Insects were collected in 8 traps (1 m × 1 m) installed under the plant canopy before the fumigation process. Samples that have been collected, sorted, and identified. The Elateridae beetles were found in as many as 527 individuals consisting of 3 subfamilies, 10 genera, and 18 morphospecies. While Staphylinidae beetles were found as many as 694 individuals consisting of 11 subfamilies, 16 genera, and 47 morphospecies. Different types of land use affect the species richness of Elateridae and Staphylinidae beetles, but differences in land use types do not affect the abundance of Elateridae and Staphylinidae beetles species.
Keyword: arboreal, keanekaragaman hayati, transformasi habitat, arboreal, biodiversity, habitat transformation

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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