Judul: Isolasi bacillus thuringiensis berliner dari berbagai contoh tanah dan toksisitasnya terhadap larva crocidolomia binotalis zeller ( Lepidoptera : Pyralidae )
Abstrak: Kekuatiran terhadap dampak negatif yang timbul akibat penggunaan insektisida kimiawi yang kurang bijaksana dalam mengendalikan hama tanaman telah mendorong para ahli untuk mengembangkan pengendalian hama secara hayati dengan lebih intensif. Organisme yang dapat digunakan sebagai pengendali hayati meliputi predator, parasit dan patogen pada serangga (de Bach, 1979). Bacillus thuringiensis merupakan salah satu bakteri yang dikenal mempunyai sifat patogen terhadap serangga, sehingga dapat digunakan dalam pengendalian hama secara hayati (van Emden, 1980). Efek patogenisitas yang ditimbulkan oleh bakteri ini berasal dari beberapa toksin bersifat insektisida yang diproduksinya, di antaranya alpha-eksotoksin, beta-eksotoksin dan delta- endotoksin (Dulmage, 1981). Di antara toksin-toksin tersebut, delta-endotoksin dan beta-eksotoksin telah dikembangkan secara komersial oleh beberapa negara. Beberapa merk dagang produk delta-endotoksin yang telah ada di Indonesia meliputi Bactospeine, Dipel dan Thuricide. Di Indonesia, insektisida mikrobe berbahan aktif B. thuringiensis ini sudah digunakan pada tanaman kelapa sawit, kubis, tomat dan tebu (Anonim, 1988).
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Judul: Isolasi bacillus thuringiensis berliner dari tanah peternakan ulat sutra serta toksisitasnya terhadap crocidolomia binotalis zeller dan spodoptera litura fabricius
Abstrak: Dalam usaha mengisolasi Bacillus thuringiensis dari tanah peternakan ulat sutra, dari 48 contoh tanah yang diperiksa, 43.75% mengandung bakteri pembentuk kristal protein. Dari 2813 isolat Bacillus yang diamati, diperoleh 32 isolat bakteri pembentuk kristal protein yang berasal dari 21 contoh tanah yang meliputi lima kabupaten. Kabupaten yang mempunyai frekuensi kandungan bakteri pembentuk kristal protein tertinggi adalah Soppeng (1.66%), sedangkan contoh tanah yang mempunyai frekuensi tertinggi adalah SPG-A 11.19 (11.45 %). Sebagian besar isolat yang diperoleh menghasilkan kristal protein berbentuk bipiramida. Selain itu, ada pula yang berbentuk oval, amorf atau bulat. Secara umum, larva Crocidolomia binotalis (instar pertama) lebih rentan terhadap Bacillus thuringiensis dibandingkan larva Spodoptera litura (instar pertama). Isolat-isolat yang toksik terhadap C. binotalis adalah SPG-A 11.10b.01, SPG-A 12.01.03, SPG-A 12.03.01 dan SPG-A 12.16.01; toksisitas ini setara dengan galur pembanding (dari Thuricide). Terhadap larva Spodoptera litura, tidak ada satupun isolat yang dapat mengakibatkan kematian 100%. Namun demikian isolat SPG-A 11.10b.01 dan SPG-A 12.16.01 ternyata lebih toksik dibandingkan dengan galur pembanding. Mortalitas tertinggi terhadap larva Spodoptera litura adalah 65 %.
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Judul: The Effects of Variance of Interest rate to Variance of Annuity Future Values
Abstrak: Time value of money is a concept that refers to the difference of the value of money due to time difference. The value of money for present time would not be the same as the value of money in the future. The value of money for present time is called as Present Value (PV) of the money and the value of money for future time is called Future Value (FV) of the money. Determination the value of money, for present and future time, depends on the time and rate of return. The value of money is determined by several factors such as inflation, fluctuation of interest rates, and government policy in securities and taxation. Due to fluctuation of the value of money we need a FV formulation, it is useful for knowing whether an investment can be profitable or not, and this information is useful also in budget analysis. Annuity is defined as a series of payments made for a specific period. The payment, fixed or varied, can be made at the beginning or at the end of the period. Annuity paid at the beginning of the period is called annuity-due and annuity paid at the end of the period is called immediate annuity-certain. The accumulated value of the annuity after few years later is called as a final value or a future value. Burnecki et al. (2003) have discussed about the FV of a fixed-rate annuity in which payments are made according to the arithmetic or geometric series. They have also examined FV for annuities in which payments are made according to arithmetic or geometric series with random rates of interest. This paper examines FV for annuity-due in which payments are made according to arithmetic or geometric series with interest rates as a random variable, which is normal distribution ,  . Future value formula is expressed in recursive form. FV for annuity-due which payments are made according to the arithmetic or geometric series with random rates of interest is calculated by theoretical way and simulation way. The random rates of interest is denoted as k k i  i  , where k i an independent random variable; i is a constant and k  is a random variable which has normal distribution ,  . By using the determined parameters, a sequence of random rates of interest are generated for theoretical calculation. Meanwhile for the simulation, the random rates of interest is generated 1000 times for the simulation. The generated data give mean value, variance, and standard deviation. Moreover, error of mean value, variance, and standard deviation from the theoretical and simulation results are calculated. Error calculation uses Symmetric Mean Absolute Percentage Error (SMAPE). The smaller the value of SMAPE is the more accurate the simulation. The interest rate variances are varied from 0.000036 to 0.0001 to study the relationship between variance of rates of interest and variance of future value. The theoretical and simulation results show that when the variance of random rates of interest increases, then the variance of FV increases linearly. FV of the annuity-due in
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