Judul: Keanekaragaman dan Parasitisasi Parasitoid pada Pertanaman Sayuran di Bogor
Abstrak: In an agricultural area, agroecosystem could influence diversity and parasitism of parasitoids as natural enemies of insect pests. A survey to learn diversity and rate of parasitism of insect pests by parasitoids had been conducted in several agricultural fields with different criteria, such as farming practice (organic and convensional), species richness of vegetable crops (5-8 sp. and 9-15 sp.) and different crop ages (3, 4 and 5 months), in Bogor from August to October 2012. By making a 50 steps line transect for every field, eggs, larvae and pupa of insect pests were collected monthly, reared in laboratory and incidence of parasitism were calculated. The results showed that there were no significant differences on diversity and rate of parasitism based on three criterias used. However, based on the diversity of vegetable plant species around, the rate of parasitism in field with less plant species diversity (5-8 sp.) was higher than the field with more vegetable plant species diversity (9-15 sp.). These results might be caused by the limited number of samplings conducted and other potential factors such as surrounding habitat, seasonal fluctuation, and complex interactions between species in agroecosystem.
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Judul: . Keanekaragaman Parasitoid Pada Areal Sawah, Kebun Sayur, Dan Hutan Di Daerah Bogor
Abstrak: Parasitoid merupakan agens pengendali hayati yang berperan dalam pengendalian hama terpadu. Pengetahuan mengenai parasitoid yang berada di suatu areal pertanaman seperti sawah, kebun sayur, dan hutan sangat dibutuhkan. Penelitian ini bertujuan untuk mengetahui keanekaragaman parasitoid dengan memanfaatkan jaring serangga dan separator pada areal sawah, kebun sayur, dan hutan di daerah Bogor. Pengambilan sampel di setiap areal, terdiri atas tiga petak (plot), dan setiap plot terdiri atas empat subplot. Pengambilan sampel dilakukan sebanyak tiga ulangan yang mewakili fase pertumbuhan tanaman khususnya areal sawah dan kebun sayur. Serangga dikoleksi menggunakan jaring serangga dan separator. Pengambilan sampel dengan jaring serangga dilakukan sebanyak 50 kali ayunan ganda untuk setiap subplot pengamatan. Serangga yang tertangkap diidentifikasi hingga tingkat famili. Serangga dan laba-laba yang tertangkap selama penelitian sebanyak 6928 individu dari 12 ordo dan 79 famili. Ordo serangga yang dominan tertangkap pada penelitian ini adalah Diptera (35.0%), Hymenoptera (26.5%) dan Hemiptera (20.8%). Total serangga Hymenoptera parasitoid yang tertangkap sebanyak 1213 individu dari 19 famili yang terdiri atas 246 individu dari 13 ordo pada areal sawah, 652 individu dari 17 ordo pada areal kebun sayur dan 315 individu dari 16 ordo pada areal hutan. Hutan memiliki nilai indeks keanekaragaman jenis Shannon-Wienner (H’) untuk Hymenoptera parasitoid paling tinggi (2.30) dibandingkan lahan sawah (1.99) dan kebun sayur (1.96). Famili Hymenoptera parasitoid yang paling dominan di ketiga lahan penelitian adalah Scelionidae, Braconidae, dan Eulophidae.
Keyword: Arthropoda, Hymenoptera, identifikasi, jaring serangga, separator

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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