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: Komposisi Functional Species Group pada Sistem Silvikultur Tebang Pilih Tanam Jalur di Area IUPHHK-HA PT Sarpatim, Kalimantan Tengah
Abstrak: Forest management can have an impact on changes in forest structure and composition of plant species. Functional species Group (FSG) may explain the unity of the trees species that are selected in a group in a forest management activities so that it can help in explaining the characteristic of biodiversity such as the quality of habitat and ecosystem processes. The purpose of this research is to know the composition of forest vegetation that the production system are managed with a Silvikultur system of TPTJ as seen from the forest structure and composition of the type that belongs to FSG for the stands and natural regeneration in log over area (LOA) and KPPN (The Conservation of Germplasm Area) IUPHHK-HA PT Sarmiento Parakantja Timber (Sarpatim), Central Kalimantan. Analysis of the composition of the stands type and structure used terraced path in the area of TPTJ and KPPN. The results showed that the types of climax on an entire swath of observations, generally have greater proportion than the group of pioneers, the number of the climax type is 100 while pioneer type is 59. The structure of the stands form a J reverse curve, it show that the composition of vegetation recovery on log over areas managed by using TPTJ and KPPN Silvikultur system has balance characteristic of uneven age forest. The value of diversity is high (H'>3). Most of tree and stands community have different communities (ID>50%).
Keyword: Bogor Agricultural University (IPB), composition of species, Forest management, Silviculture system

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