Judul: Komunitas Semut Pada Bunga Jantan Kelapa Sawit di Kebun Cimulang PTPN VIII Bogor, Jawa Barat.
Abstrak: Ants are the most successful eusocial insect in the world, since highly adapted to the environment. The objective of this research was to study ants community on male flower of oil palm. Observation of ants were done by using fix sample method during 10 minutes in 3 time periods, which is in the morning (08. 00 - 10.00 am), noon (10. 00 - 12. 00 am), and evening (13. 00 - 15. 00 pm). The observations of ants were conducted during four days in each month, i.e. April, May, June 2012. During observation we collected ant samples to identification process. Weather elements, i.e. air temperature, humidity, and light intensity were measured. Results showed that ant community on male flower of oil palm consist of nine genera belong to four subfamilies, i.e. Leptanilla (subfamily Leptanillinae), Oecophylla, Polyrhachis, Plagiolepis, Camponotus (subfamily Formicinae), Odontoponera, Platyhyrea, Pachycondyla (subfamily Ponerinae), and Myrmica (subfamily Myrmicinae). Leptanilla was a dominant ant species on male flower of oils palm. Diversity of ant community on male flower of oils palm was lower (H ’=0,99) and medium evennes (E=0,45).
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Judul: Komunitas Serangga Indigenous pada Bunga Jantan Kelapa Sawit (Elaeis guineensis Jacq.) di Kebun PTPN VIII Cimulang Bogor.
Abstrak: Oil palm is the biggest source of natural oil in the world. Oil palm is monoecious plant, but the male and female flower of the plant located at a different cluster. This study addressed to study indigenous insect community on male flower at oil palm. The insect were observed by fixed sample method on May, June 2011, January, November, and December 2012. Relationship between environment factors and insect community were analyzed by Pearson’s correlation with Sigmaplot software version 10.0. From the observation we found 5 order and 10 genera, such as Apis, Odontomachus, Camponotus, Anoplolepis, Braconid, Scaptodrosophila, Curculionid, and Dermaptera (sp1, 2, and 3). Bee, Apis cerana visited male flower of oil palm and the species role in pollination. The other, we found predatory insects, such as, Odontomachus, Anoplolepis, and Dermaptera. Result showed that the most dominant insect was Scaptodrosophila sp. The insect population significantly affected by environmental temperature.
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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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