Judul: Ground Surface Dwelling Predatory Arthropods In Soybean Fields: Abundance, Predation Pressure, And Effects Of Cultural Practices
Abstrak: Penelitian dilakukan pada pertanaman kedelai di Kecamatan Ciranjang, Kabupaten Cianjur pada MT 1997 dan 1998, dan di Kecamatan Lemahabang, Kabupaten Karawang pada MT 2000. Penelitian bertujuan untuk menentukan komposisi dan kelimpahan artropoda predator penghuni permukaan tanah dan tekanan pemangsaannya, dan mengkaji pengaruh beberapa praktek budidaya tanaman seperti mulsa jerami dan aplikasi insektisida dan herbisida. Kelimpahan predator diamati menggunakan lubang perangkap, dan tekanan pemangsaan dievaluasi menggunakan larva dan pupa Spodoptera litura (F.) sebagai mangsa umpan. Hasil penelitian menunjukkan bahwa pada permukaan tanah di pertanaman kedelai ditemukan lebih dari 15 jenis artropoda predator. Dua jenis yang paling dominan di Cianjur adalah laba-laba serigala Pardosa pseudoannulata (Boes. & Str.) (Araneae: Lycosidae) dan kumbang tanah Pheropsophus occipitalis (MacLeay) (Coleoptera: Carabidae), sedangkan di Karawang hanya jenis yang disebut pertama yang dominan. Demikian juga tekanan pemangsaan di Cianjur sekitar 9 kali lipat lebih tinggi daripada di Karawang. Perbedaan dominasi dan tekanan pemangsaan ini diduga berhubungan dengan perbedaan struktur lansekap dan intensitas penggunaan insektisida di kedua tempat tersebut. Kelimpahan artropoda predator penghuni permukaan tanah di Cianjur pada MT 1997 lebih rendah dibandingkan MT 1998, demikianjuga halnya dengan. detritivor seperti colembolan dan tungau., Cianjur during the two soybean growing seasons of 1997 and 1998, and in the sub district of Lemahabang, Karawang during 2000. The objectives were to determine the composition and abundance of ground surface dwelling predatory arthropods and their predation pressure, and to evaluate the effects of some cultural practices, i.e. straw mulching, and insecticide and herbicide applications. Ground surface dwelling predatory arthropods were monitored using pitfall traps, and their predation pressure was evaluated using larvae and pupae of Spodoptera litura (F.) as baits. Our research revealed more than 15 species of ground-dwelling predators. The most dominant predators in Cianjur were wolf spider Pardosa pseudoannulata (Boes. & Str.) (Araneae: Lycosidae) and ground beetle Pheropsophus occipitalis (MacLeay) (Coleoptera: Carabidae), whereas in Karawang only the first mentioned species. Predation pressure in Cianjur was 9 times higher than those in Karawang. The differences in species dominance and predation pressure were thought to be related to differences in landscape stuctures and intensity of pesticide uses between the two locations. Abundance of ground-dwelling predators in Cianjur during 1997 growing season was much lower compared to those during 1998, and the same with the detritivores such as collembolans and mites. Predation pressure on lepidopteran larvae placed on soil surface reached 18 individuals per 2 hours which was mostly caused by ground beetles, whereas on pupae 10 individuals per 2 hours caused by shrew. Predation pressure on larvae at distance of 1 m from field bunds were 5 times higher than those placed at 5 m. Predation occurred mostly during the night. Some of the predators climbed the soybean canopy to prey the larvae. Predation pressure decreased with the increasing size of canopy. Incorporation of straw mulch onto soil surface inreased abundance of wolf spiders, dwarf spiders, and ants. The increase of predator population generally occurred several days following mulching. Conversely, burning of straw caused deleterious effects on predators. Immediatelly after burning, abundance of wolf and dwarf spiders, ants, and rove beetles decreased 66 up
Keyword: Arthropods, Soybean, Abudance, Predation pressure

Judul: Kelimpahan Artropoda Predator Permukaan Tanah pada Tiga Ekosistem Pertanaman
Abstrak: Penelitian ini bertujuan untuk mengetahui kelimpahan artropoda predator permukaan tanah pada ekosistem pertanaman jagung, ubi jalar dan cabai di Kelurahan Situgede Kecamatan Bogor Barat, Kota Bogor. Lubang perangkap yang dipergunakan untuk mengambil artropoda predator permukaan tanah terbuat dari gelas plastik bekas air mineral bervolume 240 ml. Dalam satu buah lubang perangkap dimasukkan formalin 2% sebanyak 30 ml. Jumlah lubang perangkap pada masing-masing pertanaman 20 buah yang dipasang menyebar secara sistematis dengan jarak 5 m antar lubang perangkap. Perangkap dipasang selama 3 x 24 jam dengan interval satu minggu selama delapan minggu. Artropoda predator permukaan tanah yang berhasil ditangkap dihitung jumlahnya dan diidentifikasi di laboratorium serta diawetkan ke dalam botol film yang berisi alkohol 90%. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL). Kelimpahan total artropoda predator permukaan tanah pada pertanaman jagung berjumlah 1196 individu, sedangkan pada pertanaman ubi jalar dan cabai masing-masing berjumlah 532 dan 421 individu. Artropoda predator permukaan tanah yang dominan pada tiga ekosistem pertanaman adalah semut (Formicidae), kumbang tanah (Carabidae) dan laba-laba serigala (Lycosidae). Proporsi ketiga artropoda predator tersebut pada pertanaman jagung adalah 54.52%, 25.42%, dan 16.97%, sedangkan pada pertanaman ubi jalar masing-masing sebesar 66.92%, 19.36%, dan 13.16%, serta pada pertanaman cabai masing-masing sebesar 45.13%, 44.89% dan 6.89%. Perkembangan kelimpahan artropoda predator pada tiga ekosistem pertanaman dipengaruhi oleh serasah, sedangkan curah hujan dan Collembola tidak tampak jelas pengaruhnya. Berdasarkan data yang telah dianalisis secara statistik menunjukkan bahwa rata-rata kelimpahan total artropoda predator permukaan tanah pada pertanaman jagung tertinggi dan berbeda nyata bila dibandingkan dengan pertanaman ubi jalar dan cabai.
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Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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