Judul: Dinamika Komunitas Larva Chironomid pada Substrat Buatan di Kedalaman Berbeda
Abstrak: Larva chironomid merupakan serangga air yang paling banyak ditemukan pada ekosistem perairan tawar. Keberadaan larva chironomid sangat bergantung terhadap kondisi perairan dan substrat sebagai habitatnya. Kedalaman merupakan faktor yang mempengaruhi parameter kualitas air lainnya. Terjadinya perbedaan kedalaman memberikan pengaruh berbeda pula terhadap parameter kualitas air yang pada akhirnya berpengaruh terhadap penyebaran dan proses kolonisasilarva chironomid pada suatu habitat perairan. Seringkali penggunaan alat konvensional dirasakan kurang efisien dan efektif dalam upaya mengkaji larva chironomid oleh sebab itu substrat buatan digunakan untuk melihat proses kolonisasi dan suksesi pada larva chironomid. Penelitian ini bertujuan untuk mengetahui dinamika jenis dan kelimpahan komunitas larva chironomid.Larva chironomid yang diamati adalah larva chironomid yang berada pada substrat buatan yang diletakkan pada kedalaman berbeda. Pengamatan larva chironomid menggunakan substrat buatan pada kedalaman 2m dan 3,5m di stasiun KJA dan non-KJA yang dilakukan selama dua bulan, terbagi menjadi empat kali pengamatan. Hasil penelitian yang didapat selama pengamatan meliputi keberadaan jenis larva chironomid yang ditinjau dari kelimpahan larva chironomid, distribusi frekuensi panjanglarva chironomid, dan stage larva chironomid. Kondisi perairan ditinjau dari beberapa parameter fisika dan kimia, yaitu suhu, kecerahan, kekeruhan, padatan terlarut, padatan tersuspensi, pH, BOD, COD, dan oksigen terlarut yang terdapat dalam perairan.
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Judul: Produktivitas larva chironomidae pada substrat buatan di kedalaman perairan dan kandungan bahan organik berbeda
Abstrak: Chironomids larva plays important role in aquatic food webs. Substrates were important factor for chironomids larvae. Artificial substrates were means as tools to gain information about chironomids larva by reducing physical variation such as substrate types, water depth, and light penetration. The research was conduct to gather information about secondary productivity of chironomids larvae. Artificial substrates were positioned in cage culture and non-cage culture sites at Lido Lake, West-Java. Chironomids larva specimens were collected every day for 30 days in order to gather larvae dimensions (head capsule width and length, total body length and width). Research also conduct under laboratory condition using egg mass collected from Lido Lake which reared in a given organic content (0 mg/L, 0.5 mg/L, and 1.0 mg/L). Higher organic added in laboratory study was caused the Chironomus larvae spend less time in third instar and gain fourth instar faster (P<0,05), also emerge faster than the lower organic added. As for chironomids larvae found on artificial substrates (Polypedilum), the instar development and growth was faster at cage culture site than at non-cage culture site (P<0,05). Growth rate of chironomids larvae was affected by organic content as seen in laboratory and artificial substrates (P<0,05). Polypedilum productivity was higher at cage culture site than non-cage culture site. The COD value that represented as all type of organic was give significant effect for chironomids larvae (P<0,05) at cage culture site.
Keyword: Chironomidae larvae, artificial substrates, organic content, cluster analysis, Discriminant Analysis

Judul: Studi terhadap Perencanaan Premi Optimal dengan Reinstatements pada Perusahaan Reasuransi.
Abstrak: Reinsurance is an underwrite all or a portion of the insurance risk. Insurer paid a number of premiums to reinsurer and that premiums would be income for reinsurer. Premium plan is very important for reinsurer facing risks of submitted claims. Premium plan in this paper is premium plan of reinsurance with reinstatement. This premium is not paid in the beginning of the contract, but it is paid when the loss of the reinsurer exceed maximum bound capacity of reinsurer. For illustration purpose, it is assumed that the reinsurer’s loss is satisfied a truncated exponential distribution. Reinsurance contract minimizes the expectation of square the difference between the total premium income and the loss of the reinsurance, therefore it is said to be optimal. Minimizing the expectation of square all over premium plans can be viewed as a credibility problems. Covariance matrix of the explanatory random variables of premium plan with reinstatement is invertible, so that the premium plan has a unique solution. Optimal premium plan are unbiased and nonnegative.
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