Judul: Isolation of Bacillus thuringiensis Bacteria from Soil and Test of Toxicity to Armyworm (Spodoptera litura).
Abstrak: Bacillus thuringiensis (Bt) diketahui dapat menghambat pertumbuhan larva Lepidoptera seperti ulat grayak (Spodoptera litura), yang menyebabkan banyak masalah di bidang pertanian. Penghambatan aktivitas Bt disebabkan racun protein kristal yang diproduksi selama fase sporulasi. Penelitian ini bertujuan untuk mengisolasi Bt dari berbagai contoh tanah dan uji toksisitas terhadap larva ulat grayak instar kelima. Dua isolat berhasil diisolasi dari sampel tanah yaitu isolat 47 dan Lot 2. Isolat-isolat termasuk bakteri Gram positif, berbentuk batang, memiliki endospora subterminal, dan kristal protein. Morfologi koloni isolat berbentuk bulat, berwarna putih, dan tepian berkerut. Kedua isolat diuji dengan ulat grayak instar kelima dengan metode celup. Toksisitas isolat lebih tinggi tetapi tidak berbeda secara signifikan jika dibandingkan dengan Bt pembanding subsp. aizawai dan kontrol negatif. Kontrol negatif memiliki persentase kematian yang cukup tinggi yaitu 72,5%.
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Judul: Isolasi Bacillus Thuringiensis dari berbagai contoh tanah dan toksisitasnya terhadap larva spodoptera litura
Abstrak: Dalam usaha mengi solasi bakteri penghasil kristal protein (p.k.p.) dari 24 contoh tanah, diperoleh empat isolat yang berasal dari empat contoh tanah yang berbeda (16.67%). yaitu contoh tanah M.041, M.211, M.071, dan M.191. Pada pengamatan bentuk kristal menggunakan mikroskop kontras fase pada perbesaran 1000 kali di jumpai dua bentuk kristal, yaitu bipiramida (M.041, M.191, M.211) dan bulat (M.071). Rendahnya perolehan isolat bakteri p.k.p. dari contoh tanah yang diperiksa kemungkinan besar disebabkan karena contoh tanah yang diperiksa terlalu lama disimpan (tujuh bulan). beberapa di antaranya berasal pembakaran limbah ulat sutra dari tempat Hasil penquil an toksisitas kristal terhadap empat isolat tersebut ditambah 15 isolat hasil peneliti lain menunjukkan bahwa isolat 1.01 dan K.04 menvebabkan mortalitas mendekati 100 % pada larva S. litura. Data ini ditafsirkan dengan hati-hati dari perlu dilakukarı pengujian ulang.
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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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