Judul: Akumulasi Bahan Organik pada Substrat Buatan dengan Kedalaman Berbeda di Danau Lido, Bogor Jawa Bara
Abstrak: Lido is used for culture with floating cages (KJA). The existence of the KJA indicates high input of organic material. Organics matter study accumulation in Lido Lake is important. Artificial substrates was set learn the accumulation of organic matter at different sites (KJA site and non-KJA site) and depths (1 meter and 2 meter depth). This study was aimed to determine the accumulation of organic matter at artificial substrates at different depth at KJA site and non-KJA site. The results showed that the accumulation of chlorophyll-a different between the sites and the depths. The accumulation of AFDM different between depths and was not different between the sites. The accumulation of COD was different between the sites and was not different between the depths. Chlorophyll-a accumulation was increase to day 29th. The accumulation of AFDM and COD was increase to day 22th and was decline to day 29th.
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Judul: Pendugaan Status Kesuburan Perairan Danau Lido, Bogor, Jawa Barat, Melalui Beberapa Pendekatan
Abstrak: Danau Lido berada pada koordinat 1060 48’ 26”-1060 48’ 50” BT dan 60 44’ 30”-60 44’ 58” LS, Desa Tugujaya, Kecamatan Cigombong, Bogor, Jawa Barat. Kegiatan pemanfaatan di dalam ekosistem perairan danau berupa kegiatan perikanan dengan sistem keramba jaring apung (KJA) dan kegiatan pariwisata. Daerah di sekitar danau dimanfaatkan untuk pertanian, hotel, pariwisata, dan tempat pemukiman penduduk. Kegiatan tersebut akan menghasilkan buangan berupa bahan organik dan anorganik. Peningkatan nutrien akan meningkatkan kesuburan suatu perairan. Peningkatan secara terus menerus menyebabkan terjadinya perubahan status kesuburan perairan. Penelitian ini bertujuan untuk menduga status kesuburan perairan Danau Lido melalui beberapa pendekatan. Penelitian dilaksanakan pada bulan Mei-Agustus 2009 berlokasi di Danau Lido. Pengambilan contoh dilakukan setiap satu minggu secara spasial, baik horizontal dan vertikal sebanyak empat kali pengamatan. Pengambilan contoh secara horizontal dilakukan di dua stasiun yaitu stasiun KJA dan non-KJA, dan secara vertikal dilakukan pada kedalaman permukaan, kedalaman Secchi disk, dan kedalaman kompensasi. Pendugaan produktivitas perairan Danau Lido dilakukan melalui pendekatan Shore Line Development Index (SDI) (Cole 1983), dan Morphoedaphic Index (Ryder 1982). Pendugaan status kesuburan Danau Lido dilakukan berdasarkan Trophic State Index (TSI) (Carlson 1977), Trophic Index (TRIX) (Vollenweider et al. 1998), dan Indeks Nygaard (In) (Nygaard 1949 in Rawson 1956).
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Judul: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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