Judul: Aktivitas selulolitik sejumlah isolat kapang
Abstrak: Sebanyak 48 isolat kapang yang diperoleh dari kultur sediaan koleksi Laboratorium Mikrobiologi IPB yang merupakan hasil isolasi dari berbagai contoh dan diambil dari berbagai lokasi dilakukan pengujian untuk mengetahui aktivitas selulolitik yang dimiliki oleh masing-masing isolat. Pengujian kemampuan selulolitik pada agar cawan menggunakan medium Agar Czapek's Selulosa Mikrokristal. Hanya 5 isolat yang dilakukan asai enzimnya. Kelima isolat tersebut termasuk dalam satu genus yaitu Humicola dan tergolong unggul pada pengujian di atas agar cawan. Hanya 25 isolat yang membentuk areal jernih jelas sekali, 11 isolat membentuk areal jernih jelas dan 12 isolat membentuk areal jernih kurang jelas pada pengujian di atas agar cawan. Nilai kemampuan selulolitik tertinggi adalah 1.0000 diperoleh ketiga belas isolat yang pada pengujian di atas agar cawan membetuk areal jernih jelas sekali.
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Judul: Isolasi dan identifikasi terbatas kapang pengurai selulosa
Abstrak: Sebanyak 37 contoh (33 contoh tanah, terutama tanah perkebunan tebu, tiga contoh kotoran ternak dan satu contoh kayu lapuk) dikumpulkan untuk isolasi kapang pengurai selulosa. Isolasi langsung hanya dilakukan untuk contoh kayu lapuk; contoh-contoh lain pertama-tama dipakai untuk penyiapan kompos jerami padi yang selanjutnya digunakan untuk mengisolasi kapang pengurai selulosa melalui prosedur penyuburan pada medium cair yang mengandung kertas saring sebelum dicawankan pada agar cawan yang mengandung selulosa. Disamping itu, kapang pengurai selulosa diisolasi juga dari udara laboratorium dengan jalan memaparkan medium yang sesuai ke udara. Hanya 13 dari contoh tanah (satu di antaranya adalah tanah perkebunan coklat), kayu lapuk dan udara menghasilkan kapang pengurai selulosa melalui prosedur yang digunakan dalam percobaan. Sejumlah 21 isolat berhasil diisolasi; 11 di antaranya menunjukkan area jernih yang jelas sekali pada agar cawan yang mengandung selulosa, sedangkan tujuh yang lain menunjukkan respon yang cukup jelas dan ketiga sisanya kurang menunjukkan respon. Identifikasi terbatas kapang pengurai selulosa menun- jukkan bahwa 10 di antara isolat-isolat tersebut merupakan genus Fusarium, lima adalah Humicola, dan sisanya berturut-turut adalah Chaetomium, Cunninghamella, Syncephalastrum, Nigrospora dan Aspergillus. Satu isolat tidak dapat diiden- tifikasi karena tidak mampu bersporulasi.
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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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