Judul: Keanekaragaman dan Kelimpahan Arthropoda pada Perkebunan Teh 300-600 m dari Tepi Hutan di PTPN VIII Gunung Mas, Bogor
Abstrak: Pest control with synthetic pesticides causes various negative influences, on the environment, plant, or human health and safety. The concept of integrated pest control (IPC) began to be developed as an alternative. Understanding on the diversity and abundance of arthropods in an ecosystem is the basic consideration to implement the IPC system. The research is conducted to identify the diversity and abundance of arthropod in tea plantations within 300-600 m from edge of the forest in Gunung Mas PTPN VIII. Sampling was conducted from March until May 2013. The sampling location is in areas of tea plantations within 300-400, 400-500, to 500-600 m from the forest edge. Arthropod sampling method is to use insect netting, branches beating, and using pitfall trap. Observation performed 12 times with one week interval between observations. Number of arthropods obtained in the observations is 4403 individuals consisting of 18 orders and 58 families. Arthropod diversity was highest in locations 300-400 m from the forest edge. Arthropod abundance was highest at locations 400-500 m from the forest edge. The proportion of predatory arthropods obtained the highest is 52%, then 27% herbivor, detrivor 20%, and parasitoids and other insects about 1%.
Keyword: 

Judul: Keanekaragaman dan Kelimpahan Arthropoda pada Perkebunan Teh 600-900 meter dari Tepi Hutan di Kebun PTPN VIII Gunung Mas, Bogor, Jawa Barat
Abstrak: Tea (Camellia sinensis) is one of the plantation commodities that have a strategic role for the Indonesian economy. Almost of every year tea production has decreased, this is due to pest attack. Pest is one part of Arthropoda herbivore. Diversity and abundance Arthopoda in tea gardens need to know because some Arthropods have a beneficial role. The experiment was conducted to identify the diversity and abundance Arthropoda at tea plantation PTPN VIII Gunung Mas,. The research used three sampling methods, that is: net insect, Branches beating and pitfall trap. Identification of Arthropods in the Laboratory Bioecology Insects, Department of Plant Protection, Faculty of Agriculture, Bogor Agricultural University. Diversity Arthropoda 600 meter to 700 meters from forest edge has highest number is 49 family. The Arthropod proportions as predator is 46%, parasitoid 6%, herbivor 41% and detrivor 7%. Tea plants are generally much damage caused by Helopeltis sp. and Hyposidra talaca. Arthropod predators, parasitoids and herbivors most commonly found with nets and detrivor is most widely with pitfall trap method.
Keyword: 

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.
Keyword: