Judul: Endophytic bacteria as alternatives diseases control of bacterial wilt on ginger (Zingiber officinale).
Abstrak: Ginger is cultivated in many tropical and subtropical regions of the world. Growers expressed concern regarding the impact of pathogens on yields in recent years. Similarly, growers expressed concern regarding the effect that pathogen threats will have on the industry in the future. Bacterial wilt disease caused by Ralstonia solanacearum is an important disease on ginger plant (Zingiber officinale Rosc) in Indonesia. The objective of this research was to study the effectiveness of endophytic bacteria in inhibiting the progress of bacterial wilt disease on ginger. Three isolates of endophytic bacteria were selected and tested their antibiosis activity and plant growth promoting rhizobacteria (PGPR) against the bacterial wilt disease (R. solanacearum). The research showed that under greenhouse condition all of the ginger plants treated with the 3 isolates of endophytic bacteria produced symptoms of bacterial wilt disease 7 days after inoculation of R. solanacearum. The 3 isolates of can only inhibit 12 % of severity of bacterial wilt disease on ginger up to 42 days after the inoculation, therefore they are not effective as biocontrol agent.
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Judul: Efikasi Bakteri Endofit dan Plant Growth Promoting Rhizobacteria dalam Menekan Perkembangan Penyakit Layu Bakteri (Ralstonia solanacearum) pada Tomat
Abstrak: Tomato (Lycopersicum esculentum Mill.) is a popular vegetable in Indonesia, but the production levels are still fluctuated. One of the factors affected productivity is the incidence of bacterial wilt disease caused by Ralstonia solanacearum. Effective control to manage the disease which is environmentally friendly is the use of biocontrol agents. Application of endophytic bacterial (Staphylococcus epidermidis BC4) and Plant Growth Promoting Rizhobacteria (Pseudomonas fluorescens RH4003 and Bacillus subtilis AB89) as biocontrol of tomato bacterial wilt was expected to be an alternative tool. The objective of this study is to determine the efficacy of combination among endophytic bacteria and PGPR to suppress the development of bacterial wilt disease (R. solanacearum) and promote the growth of tomato. Depend on the growth test (growth rate and dry weight plant), the combination of bacteria that could promote the growth of tomato plant was combination of S. epidermidis BC4 75% with P.fluorescens RH4003 25%. That combination gave a better effect than the other treatments and control, but did not provide better suppression than treatment of single bacterium. Based on sinergism test, the relationship between PGPR and endophytic bacteria was an antagonistic. However, there were combination treatments which were able to suppress the disease, ie. combination of S. epidermidis BC4 50% with P. fluorescens RH4003 50% and the combination of S. epidermidis BC4 50% with B. subtilis AB89 50%.
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Judul: Pricing of Lookback Options with Floating Strike Price Using The Monte Carlo Method
Abstrak: Opsi lookback adalah opsi yang payoff-nya bergantung pada harga saham terbesar atau harga saham terkecil yang dicapai selama masa berlaku opsi. Opsi lookback dikatakan dengan floating strike price jika nilai dari strike price sebesar harga saham pada saat jatuh tempo. Nilai hampiran opsi lookback ditentukan dengan metode Monte Carlo, sedangkan nilai eksak didapat dari nilai simulasi terbesar yang mampu dihitung oleh komputer. Berdasarkan hasil penghitungan, nilai galat relatif yang dihasilkan semakin kecil dengan semakin bertambah banyaknya simulasi yang dilakukan, sehingga metode Monte Carlo untuk menghitung harga opsi lookback dengan floating strike price konvergen ke nilai eksaknya., Lookback option is an option whose payoff depends on the maximum or minimum of the asset price reached during the option period. The lookback option is said to be a floating strike price if the value of the strike price is equal to the stock price at maturity. The value of the lookback option is determined by the Monte Carlo method, while the exact value is obtained from the largest simulation value that the computer can compute. Based on the calculation results, the resulting relative error value get smaller with the increasing number of simulations performed. Therefore, the Monte Carlo method to calculate the price of the lookback option with the floating strike price converges to the exact value.
Keyword: lookback option, floating strike price, Monte Carlo method, convergent