Judul: Studi senyawa bioaktif eksopolisakarida Pleurotus ostreatus pada media cair dengan berbagai macam sumber karbon
Abstrak: Pleurotus ostreatus is one of the mushrooms that ablel to synthesize exopolysaccharides bioactive compound as result on secondary metabolite as respons to its environment (Chang and Miles 1989). Exopolysaccarides bioactive compound is very useful on medical purpose such as antimicrobial antioxidant antitumor etc.
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Judul: Studi senyawa bioaktif eksopolisakarida Pleurotus ostreatus pada media cair dengan berbagai macam sumber karbon
Abstrak: Pleurotus ostreatus merupakan salah satu jenis jamur yang mampu mensintesis metabolit sekunder berupa senyawa bioaktif eksopolisakarida sebagai respon terhadap lingkungannya (Chang dan Miles 1989). Senyawa bioaktif eksopolisakarida ini sangat bermanfaat dalam bidang kesehatan diantaranya dapat berfungsi sebagai antimikrob, antioksidan, antitumor dan lain-lain. Penelitian ini terdiri dari produksi P. ostreatus pada media cair MCM (Mushroom Complete Medium) dengan sumber karbon yang berbeda yaitu glukosa; maltosa; laktosa dan pati, pengukuran pH media, pengukuran bobot kering miselium dan pengukuran konsentrasi senyawa bioaktif eksopolisakarida (metode fenol sulfat). Selain itu dilakukan juga pengkarakterisasian senyawa bioaktif eksopolisakarida yang meliputi sifat antimikrob spektrofotemetri) dan antioksidan (metode ẞ-karoten/asam linoleat). (metode Hasil penelitian menunjukkan bahwa penumbuhan P. ostreatus pada media cair dengan berbagai macam sumber karbon memberikan pengaruh terhadap pertumbuhan P. ostreatus dan biosintesis senyawa eksopolisakarida. Dari 4 macam sumber karbon yang digunakan sumber karbon maltosa memberikan bobot kering miselium dan produksi senyawa bioaktif eksopolisakarida tertinggi sebesar 0.3532 g pada hari ke-24 dan 100.0000 mg/L pada hari ke-8. Sumber karbon maltosa juga memberikan aktivitas antimikrob tertinggi untuk E. coli, B. subtilis dan S. cerevisiae serta antioksidan tertinggi dengan nilai persentase sisa pemucatan ẞ-karoten sebesar 98.32% dibandingkan dengan sumber karbon laktosa, glukosa dan pati.
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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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