Judul: Seleksi dan Optimasi Aktivitas Biodegradasi Senyawa Piren serta Identifikasi Molekuler Bakteri Laut
Abstrak: Piren merupakan salah satu jenis kelompok senyawa Polisiklik Aromatik Hidrokarbon (PAH) berbobot molekul tinggi sehingga sulit didegradasi di lingkungan. Teknik biodegradasi dengan menggunakan bakteri laut indigenous digunakan sebagai upaya mengurangi polutan piren yang bersifat karsinogenik. Tujuan penelitian ini adalah melakukan seleksi dan optimasi aktivitas biodegradasi senyawa piren oleh bakteri laut serta identifikasi dengan metode 16S rDNA. Hasil penelitian pada uji sublimasi menghasilkan 16 isolat positif yang terbagi menjadi 3 kelompok isolat yaitu 5 isolat berdasarkan perubahan warna, 6 isolat pembentuk zona bening dan 5 isolat pembentuk keduanya. Uji pertumbuhan menyatakan terdapat 4 isolat unggul dalam mendegradasi senyawa piren yaitu isolat LBF-1-0114, LBF-0132, LBF-1-0137, dan LBF-1-0140. Isolat LBF-1-0114 dan LBF-1-0137 mampu mendegradasi senyawa piren secara optimum pada konsentrasi piren 250 ppm. Isolat LBF-1-0132 dan isolat LBF-1-0140 menghasilkan konsentrasi piren optimum 650 ppm. Keempat isolat tersebut menghasilkan konsentrasi sel optimum (OD600nm) sebesar 20. Hasil identifikasi 16S rDNA bakteri laut menyatakan bahwa LBF-1-0114 merupakan Stenotropomonas sp., LBF-1-0132 merupakan Pseudomonas aeruginosa, LBF-1-0137 adalah Halomonas sp., dan LBF-1-0140 merupakan spesies Bacillus statosphericus.
Keyword: piren, optimasi, identifikasi molekuler 16S rDNA

Judul: Identifikasi dan Pencirian Isolat Bakteri Pendegradasi Hidrokarbon
Abstrak: Biodegradation with bioremediation method is performed by utilizing bacteria that can survive in contaminated soil and shows metabolic capabilities towards pollutants as carbon sources. Identification and characterization are needed to determine the genera name of the bacterial isolates. Conventional methods is commonly used, that is by observing the morphological and physiological properties as well as the biochemical activities. This research was aimed to identify and characterize several hydrocarbondegrading bacteria already isolated from the soil contaminated with petroleum waste. Identification were performed at 20, 30, and 37 °C in a mineral-enriched medium. Identification consisted of 4 steps, namely regeneration of bacterial isolates; morphology test of isolates grown in petri dish for 24 hours, including the form, edge, color, and surface of the colony; physiology test of isolates, including simple coloring, Gram coloring , spore and capsule staining; and biochemical activity test including carbohydrate fermentation test, hydrolysis test (starch, fat, casein, and gelatin), IMViC analysis, oxidase-catalase test, motility, hydrogen sulfide and nitrate reduction analysis. The identification and characterization results were compared with guidance in Bergey's Manual Determinative of Bacteriology and showed that isolate coded MY 1, MY 3, MY 6, MY 8, MY 9, and MY FLR were Bacillus genera, MY 10 and MY 11 were Enterobacter group, and isolate MY12 was Pseuodomonas sp.
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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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