Judul: Korelasi Konsentrasi Hara N, P, K, Ca dan Fe pada Jaringan Tanaman dengan Pertumbuhan dan Produksi Metabolit Torbangun (Coleus amboinicus Lour.) secara Organik
Abstrak: Torbangun (Coleus amboinicus Lour.) is a tropical plant from the Lamiaceae family, with leaves that have a distinctive aroma and as a functional food from vegetable are used more as a medicinal plant. Bataknese lactating women in North Sumatra, Indonesia traditionally consumed torbangun leaves after giving birth with beliefs it could increase their breast milk production (a lactagogue), anti-fungal and/or anti-bacterial, analgesic, to reduce cholesterol, and to clean the uterus. The purpose of this study was to determine the correlation of N, P, K, Ca, and Fe leaf nutrient with growth and metabolite production torbangun and determine the effect of organic fertilizer with growth and metabolites production on torbangun. The trials were conducted at the experimental field, in Mulyaharja Village, South Bogor District, Bogor, West Java by using paranet with shade intensity of 55% and consists of two trials. First trial were conducted from January to March 2014, while the second trials were conducted from March to May 2014. The first trials to determine the correlation of N, P, K, Ca and Fe leaf nutrient with growth and metabolites production on torbangun. It had three replication. The data were analyzed using t-test and simple linear correlation test. The second trials were to determine the effect of organic fertilizer with growth and metabolites production on torbangun. This research used group randomized design one factor with four treatments. Each treatment was repeated four times so that there were 16 units of the experiment. The data were analyzed using analysis of variance and the significantly different effect using Duncan Multiple Range Test at 5% significance level. The trials was using three kinds of organic fertilizer i.e. chicken manure, guano fertilizer, and rice-hull ash (dose per hectare respectively for the treatment: 15 tons ha-1 chicken manure; 15 tons ha-1 chicken manure + 2 tons ha-1 guano fertilizer; 15 tons ha-1 chicken manure + 5.5 tons ha-1 rice-hull ash; 15 tons ha-1 chicken manure + 2 tons ha-1 guano fertilizer + 5.5 tons ha-1 rice-hull ash). The results showed that: (1) the best leaf position and leaf age to determine of the need of N, P, K, Ca and Fe nutrients are on the 3rd leaf position of 5 months-old plant. There is positive correlation between nutrient concentrations of K with shoot dry weight, Ca with PAL activity, and Fe with total saponins on the 3rd leaf position of 5 months-old plant; (2) In general, the combination of organic fertilization were not affected the average of relative growth rate and net assimilation rate, the growth components, the biomass components and crop production components torbangun. The combination of (15 tons ha-1 chicken manure + 5.5 tons ha-1 rice-hull ash) increased leaf nutrient concentrations. The combination of (15 tons ha-1 chicken manure + 2 tons ha-1 guano fertilizer + 5.5 tons ha-1 rice-hull ash) increased concentrations and metabolite production torbangun especially in saponins on torbangun.
Keyword: Coleus amboinicus Lour, leaf nutrients, secondary metabolites, organic fertilization, torbangun

Judul: Pertumbuhan dan Produksi Daun Torbangun (Plectranthus amboinicus Spreng.) dengan Pemupukan Organik dan Pemangkasan
Abstrak: Torbangun is a nutritious crop that increase breast milk because it contains lactagogen. Most study of torbangun plants focuses on pharmacological characteristics of plant. There is a need for research in cultivation techniques using organic fertilizer and pruning. The purpose of this study was to investigate the effect of organic fertilizer and pruning on the growth and leaf production of torbangun plant. This study used randomized block design (RBD) in the first experiment with fertilizer factor and Split plot design in the second experiment with fertilizer and pruning. Both of the experiment used Tukey‟s (Honestly Significant Difference) test. Organic fertilization is divided into 5 levels: without fertilizer, cow manure+rock phosphate, cow manure+rice-hull ash, rock phosphate+rice-hull ash, and cow manure+rock phosphate+rice-hull ash. Pruning is consisted of 2 levels: without pruning and with pruning. The results showed that fertilization using cow manure + rock phosphate + rice-hull ash increased shoot fresh weight of 125.21% compared to without fertilization. Pruning reduced plant biomass and leaf number. Torbangun growth is slow, so harvesting should have been done in a longer interval.
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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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