Judul: Identifikasi dan pengamatan status parasitoid pada Cecidochares connexa(Diptera:Tephritidae)
Abstrak: Cecidochares connexa (Diptera: Tephritidae) merupakan agen biokontrol gulma Chromolaena odorata (kirinyu). Keberhasilan C. connexa sebagai agen biokontrol dapat terganggu oleh adanya parasitoid. Penelitian ini bertujuan untuk mengidentifikasi parasitoid, mengetahui persebaran dan status parasitoid pada C. connexa dari Cigudeg (Bogor) dan Cagar Alam Pangandaran (Ciamis), Jawa Barat. Puru kirinyu yang telah berjendela dan berwarna kecokelatan dikoleksi dari Cigudeg dan Cagar Alam Pangandaran. Pupa dan atau larva C. connexa yang terdapat di dalam puru diletakkan dalam cawan Petri yang diberi alas kapas basah. Parasitoid yang keluar diawetkan dalam alkohol 70% untuk selanjutnya diidentifikasi. Sepasang imago parasitoid diinfestasikan ke dalam tiap kurungan kayu (50x50x100 cm) yang berisi satu tahap siklus hidup C. connexa. Parasitoid pada C. connexa berhasil ditemukan, yaitu Ormyrus dan Eupelmus. Ormyrus betina berwarna merah metalik dan kecokelatan pada bagian toraks dan abdomen, panjang tubuh 3.45 ± 0.14 mm, dan ovipositor termodifikasi dalam bentuk sengat. Ormyrus jantan berwarna hijau metalik dengan panjang tubuh 2.68 ± 0.02 mm.. Eupelmus berwarna hitan dengan panjang tubuh 1.24 ± 0.02 mm, kepala pipih dorsoventral, bagian dorsal abdomen rata, bagian posterior abdomen meruncing, dan ovipositor panjang. Ormyrus ditemukan di kedua lokasi. Eupelmus hanya ditemukan di Pangandaran. Persentase perolehan Ormyrus di kedua lokasi lebih besar dibandingkan persentase perolehan Eupelmus di Pangandaran. Penelitian ini belum dapat menunjukkan status parasitoid pada tahap hidup C. connexa.
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Judul: Keanekaragaman hymenoptera parasitoid pada habitat Chromolaena odorata (L.) King & Robinson (Asteraceae): studi parasitoid yang berasosiasi dengan Cecidochares connexa Macquart (Diptera: Tephritidae) di daerah Bogor
Abstrak: Penelitian Keanekaragaman Hymenoptera parasitoid dilaksanakan di beberapa tempat di Kabupaten Bogor, Jawa Barat, diantaranya Parung Panjang (HTI), Kecamatan Jasinga; Desa Setu, Kecamatan Jasinga; Gunung Bunder, Kecamatan Pamijahan; dan kampus IPB, Kecamatan Darmaga. Penelitian dilaksanakan mulai Agustus 2005 sampai Pebruari 2006. Penelitian bertujuan untuk (1) mempelajari keanekaragaman hymenoptera parasitoid pada habitat C. odorata (kirinyuh), (2) mempelajari hymenoptera parasitoid yang dominan berasosiasi dengan lalat C. connexa dan habitat inangnya C. odorata dengan mengambil studi kasus di daerah Bogor, Jawa Barat. Koleksi serangga hymenoptera parasitoid dilakukan dalam petak contoh dengan memasang perangkap nampan kuning dan perangkap malaise, serta koleksi parasitoid yang berasosiasi dengan lalat C. connexa dilakukan dengan mengoleksi puru C. odorata dari lapangan. Hasil penelitian keanekaragaman hymenoptera parasitoid pada empat lokasi berdasarkan perangkap nampan kuning dan perangkap malaise memperlihatkan bahwa kekayaan spesies (species richness) tertinggi diperoleh di Darmaga dan terendah di Parung Panjang. Hymenoptera yang dikumpulkan dari keempat lokasi adalah 1737 individu, 8 super famili, 25 famili dan 178 morfospesies. Kelimpahan individu hymenoptera parasitoid terbesar diperoleh di Gunung Bunder sebesar 566 individu. Kekayaan spesies hymenoptera tertinggi di Darmaga sebesar 121 individu. Kemiripan komposisi spesies serangga hymenoptera parasitoid memperlihatkan bahwa Setu, Gunung Bunder dan Darmaga memiliki indeks kemiripan tertinggi (0.63 atau 63%) sedangkan Parung Panjang dengan Gunung Bunder yang terendah (0.54 atau 54%). Hymenoptera parasitoid yang ditemukan berasosiasi langsung dengan lalat C. connexa yaitu famili Ormyridae (genus Ormyrus), famili Eupelmidae (genus Eupelmus), famili Eucoilidae (genus Gronotoma), dan famili Braconidae.
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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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