Judul: Ciri anatomi dan laju pengeringan alami tiga jenis kayu Cinnamomum:
Abstrak: Keberadaan jenis pohon kayu manis (Cinnamomum sp.) yang awalnya banyak tumbuh di hutan, dewasa ini sudah banyak di budidayakan pada lahan perkebunan dan pekarangan terutama untuk jenis C.burmanii. Pemanfaatan jenis Cinnamomun pada umumnya lebih menitikberatkna pada bagian kulit sementara bagian pohon lainnya untuk tujuan yang sama masih sangat terbatas kecuali pada C.Parthenoxylon. Di salah satu daeerah sentyar produk kayu mansi (Kabupaten Solok, Sumatera Barat), Kayu C.burmanii umumnya digunakan untuk keperluan kayu bakar, karena kayu ini cenderung cepat mengering dan mudah retak atau pecah.Penelitian ini bertujuan untuk mengetahui struktur anatomi serta besarnya laju pengeringan alami khususnya dari tiga jenis kayu Cinnamomum, yaitu C.burmanii, C.parthenoxylon, dan C.subarvenium.
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Judul: Anatomical characteristic and air drying rate of three Cinnamomum wood species.
Abstrak: Genus of Cinnamomum is well known enough as medicinal plant since it produces several active substances for many medicinal purposes. The bark, known as kulit kayu manis, and wood were extracted and utilized for food and pharmacy industries. Since the family consists of many species, wood identification as well as its drying rate should be examined well to proper utilization. Therefore, the aim of this research was to study the anatomical characteristic and drying rate of three Cinnamomum species, namely C. burmanii, C. parthenoxylon, and C. subavenium which were obtained from Solok (West Sumatera), Donggala (Central Sulawesi), and Maros (South Sulawesi). Wood and leaves were also collected as the sample. The wood then was utilized for anatomical and drying observations, while the remains for herbarium comparison. Both observations were carried out using the standard procedures. The result indicated that all species have similar wood characteristic such as brown to yellowish in colour; texture fine to rather fine; odoriferous while fresh; sapwood and heartwood indistinct; growth ring distinct; diffuse in porous; solitary and radial multiples of 2(-3) cells; simple perforation plates; intervessel pits alternate; oil and mucilage cells present. Specific character for each species as follow: vessel-ray pitting was much reduced to apparently simple; pits rounded or angular in C. burmanii; tyloses are absent in C. parthenoxylon; and in case of C. subavenium intervessel pittings are alternate, and the pits are polygonal in shape. Drying observation indicated that C. parthenoxylon wood is more easy to be dried with the rate of 5.14% per day compared to C. subavenium (2.55% per day) as well as C. burmanii (2.40% per day) from wet- to equilibrium conditions.
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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