Judul: Karakteristik Sifat Fisis dan Kecepatan Gelombang Ultrasonik Pohon Penghasil Gaharu Jenis Aquilaria microcarpa Baill.
Abstrak: As the increasement of its usefulness and demand, more people tried to get agarwood in any ways. Those can be lead threaten on its existence. By this condition, an innovation to detect agarwood inside the tree is necessary. The objective of this research was to know the physical properties and ultrasonic propagation characteristics of Aquilaria microcarpa Baill. The trees used in this research were 60 A. microcarpa with 3 different treatment condition, i.e trees without any infections as control, trees which infected by fungi for one time and infected three times. The testing were conducted by radial and longitudinal direction. Radial Testing were conducted to know the internal condition of the tree. Meanwhile, longitudinal testing were performed to predict the elasticity of the wood. Physical properties samples were taken from the bark to the core of the tree. Ultrasonic propagation testing in radial direction showed that its value at 20 cm, 130 cm and 200 cm of the tree height of the control trees were 969 m s-1, 915 m s-1 and 943 m s-1 respectively. For those height, ultrasonic propagation value at trees which infected for one time were 955 m s-1, 913 m s-1 and 911 m s-1respectively, meanwhile at the trees which infected for three times were 1008 m s-1, 928 m s-1 and 953 m s-1 respectively. At the longitudinal testing, the average values of ultrasonic propagation were 3366 m s-1, 3188 m s-1 dan 2817 m s-1 for control, one inoculation, and three inoculations trees, respectively. The dynamic modulus of elasticity (MOEd) value of the control trees, the trees which infected for one time and three times were 9.194 GPa, 8.498 GPa and 5.703 Gpa, respectively. Statistical analysis revelaed that the interaction between tree height measurement and treatments were not significantly influenced for ultrasonic velocity tested radially as well as single factor for both height measurement and treatments. Meanwhile, inoculation treatments were significant difference on ultrasonic velocity testing longitudinally and dynamic MOE. The average value of moisture content of the wood was 53.18%, while the density was 0.75 g cm-3.
Keyword: ultrasonic propagation, physical properties, Aquilaria microcarpa Baill, Agarwood

Judul: Karakterisasi interaksi antara tanaman aquilaria microcarpa baill dengan fusarium solani dalam pembentukan gaharu
Abstrak: Aquilaria microcarpa is native to Indonesia and has been identified and promoted as potential tree species to yield high quality agarwood (gaharu). Individual trees of this species, both in its natural habitat and plantation, do not always yield agarwood due to many influencing factors. It is estimated that only 10% trees would be able to yield the resin. A clear mechanism of agarwood formation is unknown and there is a lack of information on underlying causes and triggers of the formation due to natural complexity and uncertainty. However, natural defense mechanisms through a series of pathogenesis are presumed as naturally observed in other resin producing tree species. Research on the characterization of host-pathogen interaction in gaharu formation was carried out based on the above mentioned problems with the following specific objectives, namely: i). to identify morphological characters of A. microcarpa trees interacting with F. solani sp, ii). to determine wood anatomical characters of A. microcarpa interacting with F. solani, and iii) to verify the genotypes of A. microcarpa seedlings and trees interacting with F.solani based on microsatellites. Results on tree morphological analysis showed that two out of 17 morphological characters (descriptor), namely tree height (m) and branching angles (0), showed significant differences between inoculated and non-inoculated individuals. In addition, microscopic observations on wood anatomical characters of A. microcarpa revealed that inoculated plants clearly deposited golden-brown colored resin in pores and canticles with a distinct scent. Further verification using GC MS on the sediment deposits identified common compounds as reported in many previous research on agarwood, namely: baimuxinal, elemol, 3-phenyl-2-butanone and chromone-3-one. On the other hand, tests on the viulence degrees of F. solani showed that one out of 4 strains, i.e. F.solani FORDA 512, showed the highest level of virulence and was significantly different with other F.solani, especially if inoculated on seedlings A60, A68 and B30. Two microsatellite loci of A. crassna, i.e. 6Pa18 and 71Pa17, were successfully transferable to A. microcarpa and could be used to characterize the genotypes of Fusarium-treated seedlings (n=40), inoculated trees (n=20) and non-inoculated trees (n=20). There were differences in terms of genetic structures between tree population and seedling population. Further sequence analysis on the microsatellite fragments on the most virulent F.solani FORDA 512- inoculated seedlings indicated genotype dependant responses for both seedling and tree stages. In addition, Sequence based cladogram showed that inoculated seedlings were closely placed with inoculated trees indicating certain genetic roles in the agarwood formation. In conclusion, tree morphological (i.e. height growth and branch habit) as well as genetic and genomic characters were clearly observed and useful to provide early information on gaharu formation. It is also supported by the wood anatomy analysis showing the presence of gaharu resin.
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Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model