Judul: Respon Sorghum bicolor (Linn.) terhadap Perbaikan Tanah Masam PT Holcim Tbk, Cibadak, Kabupaten Sukabumi
Abstrak: Mining activities have some obstacles such as acid soil where soil pH is low, high Al saturation, less of macro nutrients content, especially P, K, Ca, and Mg, and low organic content. The purpose of this research was to determine the right treatment of acid soil reparation in the post-mining land and see the impact of acid soils reparation in Sorghum bicolor plants. The research consisted of two factors, namely the treatment of medium acid soil (soil color is gray, reddish brown, brown) and the HSC (Humate Substance Complex) treatment in concentration 1L: 400L, 1L: 800L, and without HSC (control). The appropriate treatment for grey and brown acid soil reparation is adding HSC with a concentration of 1L: 800L, while reddish brown soil with a concentration of 1L:400L. The reparation acid soil with HSC has some impacts on the performance improvement such as increased root length, apical root length, quantity of lateral roots, and lateral root length and leaf color.
Keyword: toxicity, Sorghum bicolor, HSC, acid soil

Judul: berjudul Respon Pertumbuhan Sorghum bicolor (L.) Moench pada Media Tanah Bekas Tambang Emas dengan Pemberian Humic Substance Complex.
Abstrak: Kegiatan revegetasi yang dilakukan di lahan pasca tambang umumnya terkendala kondisi tanah yang tidak subur untuk dilakukan penanaman sehingga menimbulkan permasalahan pertumbuhan vegetasi. Hal tersebut dikarenakan perubahan sifat fisik, kimia, dan biologi tanah akibat kegiatan eksplorasi, penataan lahan, eksploitasi dan pengaruh kegiatan ekstraksi seperti pembuangan limbah konsentrat. Salah satu cara dalam membenahi permasalahan tanah ialah dengan menggunakan HSC. Penelitian ini bertujuan untuk megukur respon pertumbuhan tanaman S. bicolor sebagai bioindikator pada tanah bekas tambang emas. Tanah yang digunakan merupakan tanah bekas kegiatan tambang emas di area Landfill PT Cibaliung Sumberdaya, Provinsi Banten. Konsentrasi larutan HSC yang digunakan yakni 1%, 2.5%, dan 5%. Parameter yang diamati meliputi panjang batang, jumlah akar primer, panjang akar primer, dan jumlah akar sekunder. Taraf konsentrasi larutan HSC 5% memberikan rataan hasil terbaik pada parameter panjang akar primer dengan 8.48 cm dan jumlah akar sekunder dengan 14 akar sekunder. Hal ini mengindikasikan pemberian larutan konsentrasi HSC dapat memperbaiki sistem perakaran pada tanah bekas tambang emas.
Keyword: HSC, S. bicolor, Tanah

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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