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: Pengaruh Penambahan Media Tanam terhadap Keberhasilan Aplikasi Pangkas Akar dan Inokulasi Fungi Ektomikoriza pada Bibit Melinjo
Abstrak: Root pruning has been known to fix root’s root system and enhancing ectomycorrhiza colonization in 2 months old melinjo seeds, but during 6 months of observation, it is not giving any significant effect to enhance growth of seedlings. This research aimed to determine the effect of replenishment of planting media and time of observation to the success rate of ectomycorrhiza fungal infection and the growth of inoculated melinjo seedlings after 8 months. Planting media replenishment affected the growth of roots and shoots of the observed melinjo seedlings. Planting media replenishment shown its influence to the growth of melinjo seedlings at the 3rd month of after weaned. Root pruning is no longer giving a significant effect, either to ectomycorrhiza colonization or melinjo seedlings growth. Fungi’s ectomycorrhiza inoculation enhance the growth of melinjo seedlings.
Keyword: Bogor Agricultural University (IPB), Ectomycorrhiza, Gnetum gnemon, Planting media, Root pruning

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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