Judul: Pencegahan Rebah dan Busuk Kecambah (Colletotrichum gloeosporioides (Penz.) Sacc.) Pada Pepaya Calina Oleh Beberapa Agens Biokontrol
Abstrak: Calina (IPB-9) is one of the superior varieties of papaya that have been released by IPB. This variety is susceptible to the causal agent of anthracnose. Anthracnose caused by Colletotrichum gloeosporioides is an impotant disease of papaya that reduce the quality of papaya in the storage. However, this patogen also caused damping-off and seedling rot at nursery. Therefore, this study purposed to evaluate the effectiveness of five biocontrol agents (Trichoderma harzianum (TH17), Gliocladium fimbriatum (G84), Bacillus subtilis (B12) and Actinomycetes (APS5 and APS12)) to reduce damping-off or seedling rot caused by Colletotrichum gloeosporioides on Calina (IPB-9). This study using in vitro test by dual culture and baiting poisonous methods and in vivo test by pouring their suspension into polybag. The result of in vitro experiments showed that TH17 and G84 were most effective to suppressing the growth of C. gloeosporioides with resistance level reached 100% on α = 5%. In the in vivo experiments, using the suspension of B12 and G84 were most effective suppressing incidental disease of damping off with relative resistance level 66.67% on α = 5%.
Keyword: Seedling disease, biocontrol agent, antraknosa, seedbed papaya calina

Judul: Keefektifan Agens Antagonis dalam Pengendalian Rebah Kecambah Cabai Merah
Abstrak: One of the major problems during cultivating of chilli is antrachnose disease. The cause of chili anthracnose can various as Colletotrichum acutatum, C. gloeosporoides, and Gloeosporium piperatum. Pathogens can cause seed decay, damping off, and anthracnose fruit rot. The objective of experiment is to evaluate the effectiveness of several antagonist agents in controlling damping off disease. The identification results show that the cause of anthracnose which can be isolated from the seeds and chilies are Gloeosporium piperatum. Antagonist agent Trichoderma harzianum (TH1), Gliocladium fimbriatum (G84), Bacillus subtilis (B12), and Pseudomonas fluorescens (P1) can inhibited the growth of pathogen colonies in vitro as 100%, 100%, 95.43%, and 39.83%. In the in vivo test is known that isolates TH1, G84, B12, and P1 is very effective (100%) in the controlling of chili damping off. Both of single treatment or combination treatment antagonist agents were not different significantly to control the damping off disease. The fourth of antagonist agents are very potential in controlling the damping off disease of red pepper germination
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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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