Judul: Improvement of mangosteen (Garcinia mangostana L.) seedling root system through agrobacterium rhizogeneses inoculation
Abstrak: Mangosteen is known as a slow growing plant, this is due to the root that is fragile, sensitive to the environmental condition and easly disturbed. Great care ia therefore required during the transplanting of seedling, which form a long taproot with few laterals. Many writers note an apparent absence of root hairs at all stage of growth. The use of Agrobacterium rhizogenes may improve root system of mangosteen.
Keyword: Hormone, Root hairs, Strain, Bacterium, T-DNA, Eksplan, In Vitro

Judul: Increasing the growth of mangosteen (Garcinia mangostana) seedlings with growing media optimation
Abstrak: Mangosteen is slowly growth trees that caused by root system development. Mangosteen root system has limited number of lateral roots and easily disturbed by unfavorable medium environmental conditions such as poor aeration, water availability, and nutrient content. The objective of this study was to enhance the growth of mangosteen seedlings by modifying media properties. The experiment was conducted in the Plastic house at Centre for Tropical Fruit Studies (CETROFS) Bogor Agricultural University, Tajur from January 2009 until May 2011. The study consisted of five experiments. The first experiment conducted to study the morphological and physiological characteristics of mangosteen seedlings that cultivate in drought conditions. Experiment arranged in a completely randomized block design with three replications. The results shown that an increasing the level of drought stress was decreased canopy and root growth include plant height, leaf area, root length, shoot and root dry weight and also root volume. Increasing the level of drought stress also led to significantly increased proline content. The second experiment was conducted to obtain the porosity of the media from various sources. The result shown that the lowest porosity in media was 53.48% and the highest was 69.63%, thus this research obtained four porosity ranges e.i.: 51-55%, 56-60%, 61-65% and 66-70%. These criteria then applied as the basis of the experimental treatments for the third study. The third experiment was conducted to analyses the growth of mangosteen seedlings at different water availability and porosity of the media. The result shown that watering intervals 6 day + water retaining polymer (WRP) at 61-65% porosity media drive the availability of optimal water and air. It caused an optimal rate of photosynthesis, stomata conductivity and the highest water potential of leaf tissue. The fourth experiment was conducted to study the growth of mangosteen seedlings at different method of fertilizer application and porosity of the media. The result shown that fertilizer application by fertigation in 61-65% porosity media produced the highest growth of root length, root dry weight, shoot dry weight and total dry weight. Nutrient uptake of N in the leaf by fertigation applications was support shoot and root growth higher than the application of granular fertilizers and slow release fertilizer. The fifth experiment was conducted to study mangosteen plant growth in two types of pots containers in various media porosity. Results shown that the use of woven bamboo pots obtained shoot and root growth higher than the polybag. As the results from previous experiments, the porosity of 61-65% seems to consistently produce the highest shoot and root growth.
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Judul: Perbandingan Kekonvergenan Beberapa Model Binomial untuk Penentuan Harga Opsi Eropa
Abstrak: Kontrak opsi (selanjutnya disebut opsi) adalah suatu jenis kontrak antara dua pihak, satu pihak memberi hak kepada pihak lain untuk menjual atau membeli aset tertentu pada harga dan periode waktu tertentu. Terdapat dua jenis opsi yang paling mendasar, yaitu opsi call dan opsi put. Berdasarkan waktu eksekusi maka terdapat dua tipe opsi, yaitu opsi Eropa dan opsi Amerika. Untuk menentukan besarnya premi opsi maka dirumuskan dua cara yaitu dengan solusi analitik dan solusi numerik. Solusi analitik telah ditemukan oleh Black-Scholes pada tahun 1973. Metode numerik yang sering digunakan adalah metode beda hingga dan metode binomial dan trinomial. Beberapa model binomial hanya mendasarkan pada perbedaan faktor naik dan turun dari perkembangan harga saham. Metode binomial terutama digunakan untuk penentuan nilai opsi yang tidak dapat diturunkan secara analitik. Di antara modelmodel binomial tersebut adalah model CRR, JR, Tian, PP1, dan PP2. Model ini konvergen ke solusi Black-Scholes. Untuk melihat kevalidan masing-masing model perlu diketahui sifat-sifat kekonvergenannya, maka perlu melihat pendekatan numeriknya.
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