Judul: Penentuan Sistem Silvikultur Berbasis pada Proses Pemulihan Vegetasi dalam Teknik Silvikultur Intensif (Studi Kasus di Areal PT Sarpatim, Kalimantan Tengah)
Abstrak: Mistakes in implementing the right silvicultural system with forest characteristic cause forest degradation. The aim of this observation is to determine the appropriate silvicultural system based on the forest standing structure and similarity of community. The analyzed data’s composition’s type and forest standing structure, forest regeneration type composition, type variety index value, ordination showed by important value index and community dissimilarity index, and cluster and biplot analysis. The result shows that non-Dipterocarpaceae commercial type community has the biggest density and proportion in all levels. Forest standing structure shapes J-reversed curve. The variety on all plots is high enough. Ubar and red meranti dominate all observation plots. Almost tree community has relatively different types in each plot. Regeneration community almost all has value for ID <50% that means the community is relatively the same. It can be seen from cluster analysis chart which part of three grup. The biplot analysis result shows that TJ6 has the most similarity between recovery and tree, while the other plots have different composition.
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Judul: Pemulihan Vegetasi di Areal Hutan yang Dikelola dengan Sistem TPTJ (Studi Kasus di Areal IUPHHK-HA PT. Suka Jaya Makmur, Kalimantan Barat)
Abstrak: Massive utilization of forest resources became one factor which caused degradation on natural forest. Forest degradation which occurred continuously could cause a change in forest composition. This could happen because seedling from invasive species dominated the area of natural forest. This research aimed to determine the composition and structure recovery of forest stands managed by TPTJ system on area of IUPHHK-HA PT. Suka Jaya Makmur, West Kalimantan. The results showed that non-commercial Dipterocarp species group had the biggest value of density and proportion among all levels Dipterocarp. Curve diameter distribution showed a balanced logged forest. The diversity in all plotarea was high. Kelampai and meranti were dominated in canopy level. Jambu monyet and kelampai were the species that dominated in seedling level. Tree and seedling had a different composition, it was shown by the ID value at >50%. This was shown by cluster analysis which divided into four groups. Commercial species proportion was generally larger than other non-commercial species.
Keyword: selective cutting and line planting, vegetation recovery, forest utilization

Judul: Analysis of Dose Distribution to the Fetus Using Monte Carlo Simulation
Abstrak: Radioterapi pada ibu hamil harus memperhatikan dosis radiasi yang diterima janin. Oleh karena itu, perlu adanya pengetahuan lebih lanjut mengenai distribusi dosis pada janin. Penelitian ini bertujuan mengetahui distribusi dosis pada janin dengan paru-paru sebagai lokasi penyinaran dengan variasi usia janin, energi, medan paparan, dan jarak janin dengan lokasi penyinaran. Percobaan dilakukan dengan metode Monte Carlo menggunakan software EGSnrc dengan fantom berukuran 40x40x40 cm3. Hasil yang didapatkan pada trimester 1 janin mendapat dosis hingga 13% pada 0,02%. Trimester 2 janin mendapat dosis hingga 100% pada 0,04% dan trimester 3 janin mendapat dosis hingga 100% pada 0,07%. Selanjutnya, ketika menggunakan energi 3 MeV janin mendapat dosis hingga 100% pada 0,03%, dan dengan energi 5 MeV janin mendapatkan dosis hingga 100% pada 0,07%. Medan paparan diatur pada ukuran 5, It is important to pay attention to the amount of radiation the fetus receives when performing radiotherapy on pregnant women. Therefore, a further study is needed regarding dose distribution to the fetus. This study aims to determine the distribution of dose to the fetus with the lungs as the radiation location with variations in fetal age, energy, exposure field, and distance of the fetus to the radiation beam. The experiment was done using Monte Carlo method using EGSnrc with a sized phantom. In the 1st trimester, the fetus received dose up to 13% at 0,02%, in the 2nd trimester, the fetus receives dose up to 100% at 0,04%, and in the 3rd trimester, the fetus receives dose up to 100% at 0,07%. Furthermore, when using 3 MeV energy the fetus gets dose up to 100% in 0,03%, and with 5 MeV energy the fetus gets dose up to 100% in 0,07%. The exposure field is set at 5×5 cm2 resulting in the fetus receiving dose up to 37% in 0,009% and with an exposure field of 8×8 cm2 the fetus receives dose up to 100% in 0,07%. At location 1, the fetus receives dose up to 12% at 0,07% and at location 2 the fetus receives dose up to 100% at 0,075%.
Keyword: Monte Carlo, dosis janin, EGSnrc, radioterapi