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: Toksisitas isolat Bacillus thuringiensis berliner dari tanah terhadap Crocidolomia binotalis zeller (Lipidopter : Puralidae) dan Spodoptera litura (Fabricius) ( Lepidoptera : Noctuidae)
Abstrak: Penelitian inj dilaksanakan di Laboratorium Pengendalian Hayati, Jurusan Hama dan Penyakit Tumbuhan, Fakul- tas Pertanian dan Laboratorium Mikrobiologi, Fakultas Kedokteran Hewan. Penelitian ini bertujuan untuk mengeta- hui toksisitas isolat B. thuringiensis dari tanah terhadap C. binotalis dan S. litura. C. binotalis instar pertama diberi perlakuan 23 isoinstar ke tiga diberi perlakuan 5 isolat dan lat, S. litura diberi perlakuan 16 isolat. Percobaan dilakukan dengan cara menyemprotkan isolat pada daun petsai untuk C. binotalis dan daun kedelai untuk S. litura. Gejala luar yang tampak pada larva akibat infeksi B. thuringiensis yaitu aktivitas dan tanggap terhadap sen- tuhan berkurang, nafsu makan berkurang dan ukuran tubuh mengec11. Jika larva mati warnanya menjadi coklat dan kemudian menghitam, sangat lunak dan mudah hancur. Dari isolat isolat yang diuji hanya ada 2 23 yang toksik terhadap C. binotalis instar pertama, yaitu isolat TTS 48 dan TTS 55, sedangkan untuk instar ke-tiga tidak ada isolat yang toksik. Dari 16 isolat yang dicobakan pada S. litura ada 2 isolat yang tingkat toksisitasnya rendah dan persentase kematian terkoreksinya juga rendah. ada isolat yang toksik. Dari 16 isolat yang dicobakan pada S. litura ada 2 isolat yang tingkat toksisitasnya rendah dan persentase kematian terkoreksinya juga rendah…
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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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