Judul: Karakteristik Struktur Anatomi Bagian Kayu Tarik dan Kayu Opposite pada Kayu Balik Angin (Alphitonia excelsa)
Abstrak: Wood is a very variable substance, with differences occurring among species and genera, within a species as well as within each individual tree because of a metabolism product. Wood variability becomes higher if the stem contains tension wood. The purpose of this study was to analyze anatomical structure, fiber quality and some physical properties of Alphitonia excelsa tension wood and compare them to those of the opposite one. Demarcation between juvenile and mature wood will also be assessed based on their fiber length, wood density, and microfibril angle. The results showed that there are differences in anatomical characteristics, physical properties, and the quality of the wood fibers between tension wood and opposite wood, except for fiber length, texture, color, grain, odour and taste, rays, perforation plate, and porosity. Average microfibril angle in tension wood was 23.81º, while in opposite wood was 26.23º in average. Moisture content, wood density, and specific gravity on tension wood region tended to be 6.5%, 11.63% and 13.16% higher than those of its opposite wood region.
Keyword: 

Judul: Kajian Struktur Anatomi dan Sifat Fisis Kayu Balik Angin (Alphitonia excelsa): A Lesser Known Species from Kalimantan
Abstrak: Scarcity of wood supply for wood industries in Indonesian could be solved by searching several potential of wood species from natural forest. Among them, balik angin (Alphitonia excelsa) is one of the promising species since it belongs to faster grown lesser known wood species and abundant. To promote this species effectively, its anatomical structure and physical properties have to be studied. From the research it was showed that heartwood and sapwood are almost similar in colour (light gray), decorative (“V”-type), medium and even textured, straight grain, smooth, lustrous, medium hardness and odourless. Microscopic characteristics are 1, 4, 7, 9, 10, 13, 22, 30, 44, 47, 53, 56, 61, 65, 66, 69, 78, 79, 93, 97, 106, 109, 138, 153 and has resin material within the ray parenchyma cells. Average values of fiber length, moisture content, wood density, specific gravity, and MFA were 1042.84 μm, 13.03%, 0.49 g/cm3, 0.43 and 17.1˚, respectively. Fiber quality of this wood belonged to class of II-III with strength class of III.
Keyword: 

Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
Keyword: