Judul: Respon Pertumbuhan Anakan Shorea leprosula Miq, Shorea mecistopteryx Ridley, Shorea ovalis (Korth) Blume, dan Shorea selanica (Dc) Blume terhadap Tingkat Intensitas Cahaya Matahari
Abstrak: Meranti is one of the commercial wood that has been recognized by many countries of Southeast Asia with a variety of trade names, especially the kind of red meranti (Shorea spp.). Red Meranti, including endemic species in Indonesian including threatened extinct namely Shorea leprosula (Kalimantan), Shorea ovalis (Kalimantan) and Shorea selanica (Maluku) are entered into the IUCN Red List (Ashton 2011). The giving of shade on meranti saplings is very important in both the field and in the nursery. The giving of shade plants performed as meranti is the kind of gap opportunist in where light is a limiting factor for early growth. This research observe the growth response of red meranti saplings of Shorea leprosula, Shorea mecistopteryx, Shorea ovalis and Shorea selanica with treatment shade 0% (light intensity 100%), 20% shade (light intensity 80%), 40% shade (light intensity 60 %), 60% shade (light intensity 40%). The experiments did with two factorial completely randomized design. The results of research treatment shade showed that red meranti saplings of Shorea leprosula, Shorea mecistopteryx, Shorea ovalis, and Shorea selanica real influential. The treatment shade 60% (light intensity 40%) give the best response to the growth of Shorea leprosula, Shorea mecistopteryx, Shorea ovalis, and Shorea selanica.
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Judul: Pengaruh Intensitas Cahaya Matahari Terhadap Pertumbuhan Jenis Shorea parvifolia dan Shorea leprosula dalam Sistem TPTI Intensif (Studi Kasus di Areal IUPHHK-HA PT. Sarpatim, Kalimantan Tengah)
Abstrak: Silvicultural system of Intensive Indonesian Selective Cutting and Planting (TPTI) comprises the techniques of regeneration, tending and harvesting of a stand or forest for producing certain products, and is designed to create sustainable management of natural production forest. In relation with that, there is a need for research on the effect of light intensity on the growth of Shorea parvifolia and Shorea leprosula species (meranti), to obtain information on light intensity where the growth of meranti is maximum. Such information could be used as the basis of consideration in the action of environmental manipulation on intensity of lights which enter the forest floor, to increase the growth of the two species of tree for achieving high productivity. The research was conducted in operational planting strip in block of PUP (Permanent Measurement Plot) of RKT (Annual Working Plan) 2005 and 2006, with 4 plots, and in each plot there were 3 planting strips comprising 120 strip plants. Plot size was 100 m X 100 m. The collected primary data were among other things total height of plants, plant diameter, wet bulb and dry bulb air temperature, humidity, light intensity in the planting strip and health condition of the trees. The collected secondary data were among other things site map, general condition of the research site (which comprised site geographic position, climate, rainfall, soil type, topography), and data of the tree diameter and height of the previous years. Diameter growth of Shorea parvifolia in plot which was rather steep of strip 2 possesed the greatest increment (1.59 cm / year) which differed significantly at 5 % level, and was affected by sunlight intensity as much as 6.85 %. On the other hand, diameter growth in level plot of strip 2 possessed the largest increment of 2.91 cm / year which differed significantly at 5 % level and was affected by sunlight intensity of 16.6 %. It could be shown that the diameter growth of Shorea leprosula was greater than that of Shorea parvifolia. The largest increment of diameter and height of S. parvifolia were respectively 1.59 cm / year and 140.88 cm / year. The largest increment of diameter and height of S. parvifolia were respectively 1.50 cm /year and 247.05 cm / year. The largest increment of diameter and height of S. leprosula were respectively 2.91 cm /year and 217.58 cm / year. The largest increment of diameter and height of S. leprosula were respectively 2.95 cm /year and 289.35 cm / year. During observation of S. parvifolia and S. leprosula growth, there were diameter increments as affected by IC sunlight exposure as large as 1.59 cm / year with IC exposure of 397.07 foot candle; and 2.91 cm / year with IC exposure 278.2 foot candle.
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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