Judul: Pendugaan Potensi Simpanan Karbon Di Atas Permukaan Lahan Di Areal PT ANTAM UBPE Pongkor, Jawa Barat
Abstrak: Hutan dapat menjadi sumber emisi karbon (source) dan juga dapat menjadi penyerap karbon dan menyimpannya (sink). Kemampuan hutan dalam menyerap dan menyimpan karbon tidak sama baik pada berbagai tipe hutan. Saat ini, diperlukan suatu kegiatan mengkuantifikasi serapan karbon dari biomassa baik di hutan alam maupun hutan tanaman yang ada di perusahaan pertambangan seperti PT ANTAM UBPE Pongkor, Jawa Barat. Tujuan dilakukan penelitian ini untuk menghitung potensi biomassa dan simpanan karbon di atas permukaan lahan pada hutan alam dan hutan tanaman di areal PT ANTAM UBPE Pongkor, Jawa Barat. Pengukuran biomassa pohon, tiang, pancang, dan nekromassa dilakukan dengan metode non destruktif sedangkan pengukuran biomassa tumbuhan bawah dan serasah menggunakan metode destruktif. Hasil penelitian menunjukan bahwa potensi biomassa di atas permukaan lahan di hutan alam dan hutan tanaman sebesar 103.13 ton/ha dan 56.11 ton/ha. Simpanan karbon di atas permukaan lahan di hutan alam dan hutan tanaman sebesar 47.44 ton/ha dan 24.66 ton/ha. Hasil pendugaan potensi simpanan karbon berbanding lurus dengan potensi biomassa.
Keyword: biomassa, hutan alam, hutan tanaman, karbon

Judul: Pendugaan Potensi Simpanan Karbon di Atas Permukaan Lahan Pasca Tambang PT. Antam UBPE pongkor, Jawa Barat
Abstrak: Post mining land reclamation is one of the effort to increase carbon stock. Reclamation activities will recover the post-mining degraded lands. The objectives of this study were create an allometric of some tree species, estimate and compare the carbon stock on the land of PT. Antam UBPE Pongkor, West Java in 2001, 2002, and 2003 planting years. Biomass measurement of tree, pole, and sapling was done with non destructive method, while understorey, litter, and necromass was done with destructive method. The allometric which used in this study has the highest R2 value, so that all of allometric can be used for estimate tree’s volume. The result of this study show the highest potential carbon found in 2001 planting years, the potential carbon of this planting year is 107.14 ton/ha, and then 2003 planting years is 101.44 ton/ha, and 2002 planting years is 94.18 ton/hnd a. Carbon potential differences caused by composition, structure, stand density, and canopy coverage
Keyword: Bogor Agricultural University (IPB), PT. Antam UBPE Pongkor, carbon, biomass

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