Judul: Pruning Akar untuk Meningkatkan Keberhasilan Infeksi Fungi Ektomikoriza pada Bibit Melinjo (Gnetum gnemon) Umur 7 Bulan
Abstrak: The success of ectomycorrizha fungi infection on 7 months age of melinjo seedling may be improved through root pruning technique. Root pruning may improve new lateral root’s growth. The purposes of this research are to implement root pruning to enhance ectomycorrizha fungi infection success and melinjo seedling’s growth. This research is done by using split plot design. The source of ectomycorrizha inoculum as main plot consist of 3 types: control, infected seedling of ectomycorrhiza, and soil inoculum. The root pruning rate as main plot also consist of 3 types, they are: 0%, 30%, and 50%. Observation is done on month 5th and month 6th after treatment. The result of this research indicates that root pruning is able to enhance melinjo seedling’s growth and increase ectomycorrhiza’s colonization (Scleroderma spp.) after 6 months observation. The source of inoculum is able to enhance ectomyrorrhiza’s colonization but had not give significant influence toward melinjo seedling’s growth on month 6th after treatment.
Keyword: Scleroderma, root pruning, Gnetum gnemon, ectomycorrhiza

Judul: Pruning Akar untuk Meningkatkan Kolonisasi Ektomikoriza pada Bibit Melinjo (Gnetum gnemon) Umur 2 Bulan
Abstrak: Melinjo seedling inoculation with ectomycorrhizal fungi should be done when the seedlings are still young, to get the seedlings with the high colonization. Ectomycorrhizal colonization on the young melinjo seedlings (age 2 months) perhaps can be improved by root pruning. Objective at the research is to study the effect of root pruning toward the increasing of ectomycorrhizal colonization and melinjo seedling growth (age 2 months). The research used split plot design. Source of ectomycorrhizal inoculum as main plots consisted of 3 levels, i.e. control, ectomycorrhizal seedling, and soil inoculum. Root pruning as sub plots consisted of 3 levels, i.e. 0%, 30%, and 50%. The results showed that root pruning can improve the root system of melinjo seedlings through the increasing of branching roots and could increase ectomycorrhizal colonization. Root pruning at 50% level that combined with soil inoculum more effective to increase rate of ectomychorrhizal colonization compared with other treatments. Increasing of ectomychorrhizal colonization did not significantly improving the growth of melinjo seedling.
Keyword: root pruning, Gnetum gnemon, ectomychorrhizal

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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