Judul: Kelimpahan Dan Keragaman Artorpoda Predator Dan Artropoda Lainnya Pada Tanaman Talas (Colocasia Esculenta (L) Schoott) Di Situ Gede, Bogor
Abstrak: Informasi kelimpahan dan keragaman artropoda predator dan artropoda lainnya pada tanaman talas diperlukan sebagai langkah awal dalam penerapan tehnik pengendalian hama terpadu (PHT). Tujuan penelitian ini adalah mengetahui kelimpahan dan keragaman artropoda predator dan artropoda lainnya pada tanaman talas di Situ Gede, Bogor. Metode yang digunakan dalam penelitian ini adalah pengamatan langsung, penggunaan perangkap (pitfall trap), dan sticky trap. Hasil penelitian menunjukkan bahwa artropoda herbivora memiliki kelimpahan tinggi, sementara artropoda predator lebih beragam. Proporsi artropoda sebagai predator, herbivora, detrivora, dan parasitoid pada pertanaman talas secara berturut-turut adalah 19%, 66%, 10%, 5%. Artropoda predator yang dominan adalah semut (Hymenoptera: Formicidae) sebanyak 1324 individu. Artropoda herbivora yang dominan adalah kutu daun (Hemiptera: Aphididae) sebanyak 11059 individu. Artropoda detrivora yang dominan adalah serangga pengurai tanah (Collembola: Entomobryidae) sebanyak 624 individu. Artropoda parasitoid yang dominan adalah Encyrtidae (Hymenoptera) sebanyak 456 individu.
Keyword: PHT, pitfall trap, sticky trap

Judul: Kelimpahan Artropoda Predator dan Artropoda lainnya pada Pertanaman Kelapa Sawit (Elaeis guineensis Jacq.) di PTPN VIII Cikasungka, Bogor.
Abstrak: Informasi kelimpahan artropoda predator dan artropoda lainnya pada tanaman kelapa sawit sangat diperlukan dalam pertimbangan pengambilan keputusan pengendalian dengan menggunakan teknik pemanfaatan musuh alami. Tujuan penelitian ini adalah mengeksplorasi dan menginventarisasi artropoda predator dan artropoda lainnya pada tanaman kelapa sawit di PTPN VIII Cikasungka, Bogor. Pengamatan ini dilakukan dengan 3 macam metode yaitu pengamatan langsung digunakan untuk mengamati dan mengambil artropoda yang berada pada tajuk dan disekitar tanaman sampel, pitfall trap digunakan untuk mengambil artropoda yang terdapat pada permukaan tanah, dan jaring serangga digunakan untuk mendapatkan artropoda yang aktif terbang. Hasil penelitian menunjukkan bahwa proporsi peran artropoda sebagai detrivor, predator, hama, dan parasitoid berturut-turut sebesar 71%, 21%, 7%, dan 1%. Artropoda predator yang paling dominan adalah semut (Hymenoptera: Formicidae) sebanyak 493 individu. Artropoda herbivora yang paling dominan adalah belalang (Orthophtera: Acrididae) sebanyak 225 individu. Artropoda detrivor yang paling dominan adalah serangga pengurai tanah (Collembola: Isotomidae) sebanyak 2 175 individu. Artropoda parasitoid yang paling dominan adalah (Hymenoptera: Eulopidae) sebanyak 80 individu.
Keyword: kelapa sawit, musuh alami, parasitoid

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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