Judul: Aktivitas repelensi ekstrak sepuluh spesies tanaman terhadap Blatella germanica L. (Dictyoptera: Blatellidae)
Abstrak: Blattella germanica L. (Dictyoptera: Blattellidae) merupakan salah satu spesies kecoa yang mampu beradaptasi dengan kehidupan manusia. Serangga ini dapat hidup pada berbagai kondisi lingkungan baik. di luar ruangan maupun di dalam mangan. Serangga ini dapat bertindak sebagai agen penularan penyakit dan dapat menyebabkan alergi pada orang yang sensitif atas keberadaannya. Oleh sebab itu, diperlukan upaya pengendalian kecoa B. germanica.
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Judul: Repelansi beberapa ekstrak tanaman terhadap Periplaneta Americana L. (Dictyoptera : Blattidae)
Abstrak: Kecoa, Periplaneta americana L. (Dictyoptera: Blattidae), merupakan hama rumah tangga yang tersebar di seluruh dunia yang aktif pada malam hari. Serangga ini memakan segala jenis makanan. Dalam kehidupan manusia, serangga ini seringkali menimbulkan masalah karena dapat menularkan berbagai penyakit dan juga mengganggu kenyamanan manusia. Hingga saat ini, pengendalian secara kimiawi masih efektif dilakukan dengan menggunakan insektisida sintetik. Namun upaya pengendalian secara kimiawi banyak menimbulkan dampak negatif seperti resistensi dan racun kronis yang persisten terhadap organisme bukan sasaran, dapat membahayakan kesehatan manusia, kelestarian sumber daya alam dan lingkungan hidup sekitarnya. Untuk itu perlu dicari alternatif pengendalian lain yang dapat meminimalkan dampak negatif tersebut. Sebagai alternatif pengendalian secara kimiawi adalah dengan penggunaan insektisida botani yang berbahan aktif senyawa tumbuhan. Penelitian ini bertujuan untuk mempelajari aktivitas repelensi sepuluh ekstrak tanaman terhadap kecoa P. americana L. (Dictyoptera: Blattidae). Penelitian dilaksanakan sejak bulan Februari hingga September 2002 di Laboratorium Fisiologi dan Toksikologi Serangga, Jurusan Hama dan Penyakit Tumbuhan, Fakultas Pertanian, Institut Pertanian Bogor. ...
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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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