Judul: Produktivitas Lebah Trigona spp. sebagai Penghasil Propolis pada Perkebunan Pala Monokultur dan Polikultur di Jawa Barat
Abstrak: One of the stingless bee, namely Trigona spp. is a good propolis producer but, until now the species is not cultivated yet. Propolis is made from resin collected by bee from plants and mixed with enzim from bee saliva. The best resin produced by plants that used as medicine. Nutmeg is original plant from Indonesia, and commonly used as medicine. The aim of this study was to analyze the productivity of Trigona bee as propolis producer which were cultivated at monoculture and policulture plantations. This study was carried on at the Experimental Plantation (Cicurug Monoculture Farm) and Community Plantation (Cijeruk Policulture Farm) and data collection were conducted for three months from March until May 2012. Methodology used in this study was direct observation on daily activity and measurement the colony weight of Trigona that was kept at two different farms. Propolis production was measured in the two agroecosyestems and analysed to measure the flavonoid content of propolis produced in each locality. The results showed that the weight of Trigona at monoculture farm was higher than those at the policulture (299 g : 170 g), but the weight of propolis at policulture farm was higher than monoculture farm (92,75 g : 65,57 g). The result of flavonoid content of propolis at monoculture farm is 0,186%, and 0,288% at policulture farm. The difference might be related to the activity of the stingless bee which were more active at the monoculture farm to develop their colony rather than their product (propolis). It shows that the activity of the stingless bee at monoculture was more active than those at the policulture farm.
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Judul: Aktivitas dan Produktivitas Lebah Trigona laeviceps di Kebun Polikultur dan Monokultur Pala (Myristica fragrans)
Abstrak: Trigona laeviceps is belong to the family Apideae. It has belong to no sting (stingless bee) and produce propolis, honey and bee pollen. This study aimed to study and compare the activity and productivity of Trigona laeviceps in polyculture and monoculture plantation nutmeg (Myristica fragrans). The study used completely randomized with type of garden (policultures and monocultures of nutmeg) Trigona activity and productivity (honey, pollen, propolis and development of colonies) were the variables and the obtained data were analyzed by ANOVA T - test with 95% confidence interval. observation the activity in and out in the morning until late afternoon (from 06:00 to 17:00), and productivity seen from the weight indication colony, honey, propolis and bee pollen. Trigona bee activity in the nutmeg monoculture plantation (83 %) was higher than in polyculture garden (84 %) and determined by light intensity. Activity in the garden polyculture affected by temperature pollen and propolis production percentages were higher in policulture plantation, while Trigona colonies in nutmeg monoculture had a better development. However, in this study, ambient factors (temperature, Rh, and light intensity) do not significantly determined variation in Trigona productions.
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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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