Judul: Respon cendawan tanah terhadap herbisida glifosat
Abstrak: Glifosat (N-(fosfonometil)glisina) merupakan herbisida post emergent, berspektrum luas dan non selektif. Walaupun diaplikasikan secara post emergent, molekul glifosat mencapai tanah juga dan secara kuat akan diikat oleh partikel-partikel tanah. Residu glifosat yang terdapat di dalam tanah akan menyebabkan dampak terhadap keadaan tanah termasuk mikroorganisme tanah. Penelitian ini bertujuan untuk memperoleh cendawan tanah yang mampu tumbuh cepat pada media dengan glifosat konsentrasi tinggi dan mengamati pertumbuhannya pada berbagai konsentrasi glifosat. Sebanyak 72 isolat berhasil diisolasi dari tanah Biotrop (Bogor) dan Sukabumi yang telah disemprot glifosat 1445 gram dalam 404 liter larutan per hektar tanah (disemprot pada konsentrasi 3,577 mg/ml atau konsentrasi lapang) menggunakan media kecambah kacang hijau. Lima isolat dari 72 isolat mampu tumbuh cepat (lebih dari setengah diameter cawan petri selama 5 hari) pada glifosat 8 x konsentrasi lapang. Kelima isolat tersebut diidentifikasi sebagai Trichoderma koningii B5.1, Trichoderma sp. B9.5, anggota Mucorales isolat B21.1, Aspergillus flavus S7.2, dan Trichoderma harzianum S10.1. Pertumbuhan semua cendawan terpilih kecuali Trichoderma harzianum S10.1 meningkat seiring peningkatan konsentrasi glifosat sampai 2 x konsentrasi lapang, bahkan sampai 4 x konsentrasi lapang pada anggota Mucorales isolat B21.1. Pertumbuhan Trichoderma harzianum S10.1 menurun seiring peningkatan konsentrasi glifosat. Pertumbuhan semua cendawan terpilih terhambat pada glifosat 8 x konsentrasi lapang.
Keyword: Glifosat, cendawan, pertumbuhan

Judul: Deteksi penguraian herbisida glifosat oleh berbagai isolat cendawan tanah
Abstrak: Glifosat (N-fosfonometil glisina) merupakan bahan aktif dari herbisida seperti Roundup. Mikrob merupakan pengurai utama residu glifosat di tanah, namun demikian penggunaan glifosat secara terus- menerus dapat menimbulkan dampak negatif terhadap lingkungan. Sebanyak lima isolat cendawan yang resisten terhadap konsentrasi glifosat tinggi masing-masing ditumbuhkan pada tiga macam media cair dan diinkubasi selama 7 hari. Kelima isolat cendawan tersebut ialah Aspergillus flavus S7.2, Trichoderma harzianum $10.1, Trichoderma koningii B5.1, Trichoderma sp. B9.5, dan Mucorales B21.1. Sedangkan ketiga macam media cairnya ialah media mengandung ekstrak kecambah kacang hijau (MT), media mengandung ekstrak kecambah kacang hijau dan glifosat 5,1 mg/ml (MTG), dan larutan glifosat 5,1 mg/ml (MG). Pertumbuhan cendawan diamati melalui bobot kering koloni dan hasil penguraian glifosat dideteksi melalui kromatografi lapis tipis (KLT). Asam aminometilfosfonat (AMPA), glisina, dan glifosat murni digunakan sebagai standar dalam KLT. Isolat cendawan Trichoderma sp. B9.5, dan Mucorales B21.1 memiliki bobot kering lebih besar (berbeda nyata) pada MTG dibandingkan dengan MT. Hal ini menunjukkan bahwa glifosat mampu meningkatkan pertumbuhan kedua isolat. Meskipun demikian pada kedua isolat tersebut belum tampak hasil uraian glifosat dengan metode KLT. Sedangkan A. flavus S7.2, T. harzianmum S10.1, dan 7. koningii B5.1 pada MT maupun MTG memiliki bobot kering yang tidak berbeda nyata. Kelima isolat cendawan mungkin belum mampu menguraikan glifosat meskipun telah diinkubasi selama 28 hari.
Keyword: cendawan, glifosat, dan penguraian

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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