Judul: Hubungan antara inhibitor enzim pada Sengon dengan pertumbuhan larva Boktor dalam Artificial Diet
Abstrak: INTRODUCTION. Sengon (Paraserianthes falcataria (L) Nielsen) is widely planted for reforestation programs, especially in establishment of community forest as its timber is utilized for constrction, package box, lighter as well as raw material of pulp and paper. However, there is main problem in sengon plantation, which is boktor (Xystrocera festiva Pascoe) pest attact. In the midgut of boktor larvae it was detected trypsin and α-amylase enzymes activity. Whereas on sengon tree it was reported contains inhibitory substance against trypsin and α-amylase enzymes of boktor larvae. The inhibitory activity was assumed as defense mechanism of sengon tree against the pest attack. In order to clarify the assumption an investigation on the correlation between trypsin and α-amylase inhibitor of sengon with larval growth on an artificial diet is necessary. The experiments aimed at obtaining correlations between the activities of trypsin and α-amylase inhibitors of sengon tree with the growth of boktor larvae, with small (±1,5 cm) and big sizes (±3 cm) on an artificial diet containing respective sengon tree materials. METHODOLOGY. Plant material used was the wood and the bark of sengon trees made into powder by freeze drying. Two provenances were selected, i.e Kediri and Solomon, consisted of two conditions each i.e. healthy and heavily infested. Both small (±1,5 cm) and big sizes (±3 cm) of boktor larvae were put in a big test tubes filled with artificial diet, which contained powder of sengon wood and bark, as their main feed outside their natural habitat. Larvae growth parameters (weight, head diamaters, length and diet consumption) were observed and measured every two weeks. Data on trypsin and α-amylase inhibitors was obtained from biochemical analysis of wood and bark powders using a spectrophotometer. Two kinds of data, larval growth parameters and inhibitors activities, were then correlated using Pearson correlation in Microsoft Excel 2007. RESULTS AND CONCLUSION. Result of the experiments showed that correlation obtained between inhibitor activities of each tissue of each condition and corresponding larvae growth parameters was not all negative, as espected. Out of 64 observations about 35 are positive and about 29 are negatively correlated. In a healthy tree with high trypsin inhibitor activity small size boktor larvae do not prefer attacking. On the contrary similar larvae prefer heavily infested tree with low inhibitor activity. Healthy tree with high α-amylase inhibitor activity will be saved from big size boktor larvae preferences. The opposite accurs on heavily infested tree with low inhibitor activity, which is preferred by big size larvae. In order to obtain negative correlation for trypsin inhibitor it was suggested to do similar experiments using small size larvae, while for α-amylase inhibitor it was suggested using big size larvae.
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Judul: Biologi larva boktor (Xystrocera festiva Pascoe) dalam makanan buatan (Artificial diet) dengan bahan dasar serbuk kayu sengon (Paraserianthes falcataria)
Abstrak: The constraints faced in the development of sengon plantation forest is that i he sengon trees are planted in monoculture condition, they are very susceptible t -oktor (Xystrocera festiva) pest attack. During larvae stadium, boktor pest, in s r h for food, will bore sengon tree stem. This boktor larvae activity causes age on sengon trees, and even could cause death of the sengon plants. Various e • rts to control this pest have been conducted, although the results are still not e ective yet. This phenomenon was related with lack of knowledge concerning goktor larvae, because activities of this larvae occured in the inside parts of s gon trees, which made them difficult to be observed directly in the field. erefore, observation in the laboratory will help providing information on the biol gy of boktor pest, which comprise growth, life cycle, and feeding behavior. Artificial diet is an artificial food consisting of natural ingredients and chemicals with certain amount of dosage as a substitute for host plant for boktor larvae, to allow easy observation in laboratory. Materials used in this research was sengon wood powder comprising those of ijanjarnegara provenance in sick condition, Banjamegara provenance in healtpy condition, Solomon provenance in sick condition, Solomon provenance in healt y condition (each of them has undergone process of freeze dry), yeast extr ct, streptomycin, sucrose, agar, aquadest, ascorbic acid (vitamin C), benzoate, vitamin B, NaCl, dolomite, olive oil and small size boktor larvae (1.5 - 2.3 cm). The observed variables were weight of larvae, length of larvae, diameter of larvae head, and weight of food consumed by the boktor larvae. Measurement and replacement of food was conducted each week for a period of 8 weeks. Results of analysis of variance showed that factor which gave the largest contribution in creating significant effect on larvae growth (larvae weight, larvae lengili, larvae head diameter) and amount of food consumed by boktor larvae, was provenance factor. On the other hand, factor of condition (sick or healthy cond"tion of the trees which provide the wood powder) did not give significant effe on all observed variables during 6 weeks period. Factor of condition exe ed its effect, only during week-7 and week-8. Graph pattern of average gro h of larvae weight and length showed that during week -5, larvae from all treatments, on the average, underwent significant decrease in length and weight. This was because during the week -5, many of the larvae underwent molting. Results of Duncan test showed that provenance which exerted the greatest effect was Solomon provenance. The best growth of boktor larvae was in Solomon provenance with larvae weight increment of 72 mg, larvae length increment of 4.47 pun, and larvae head increment of 0.67 mm. During 8 weeks observation in laboratory, feeding behavior of boktor larvae in artificial diet was similar with fi ing behavior of boktor larvae in trees in the field .
Keyword: sengon, artificial diet, boktor

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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