Judul: Perubahan struktur dan kelimpahan zooplankton dan 200 benthos sehubungan dengan peningkatan bahan organik di beberapa lokasi Situ Ciburuy, Kabupaten Bandung
Abstrak: Hasil kegiatan manusia dan proses alami di areal basin drainase perairan Situ Ciburuy berupa bahan organik dan anorganik akan mempengaruhi struktur dan kelimpahan zooplankton makrozoobenthos invertebrata. Untuk mendeteksi efek perubahan kelimpahan bahan organik terhadap organisme akuatik, maka dilakukan pendekatan : (1) Penentuan zonasi atas dasar pola penyebaran bahan organik aktual di lapisan permukaan dan dasar. (2) Pemantauan kandungan bahan organik menurut zone dan waktu sampling. (3) Telaah perubahan kandungan bahan organik menurut zone dan waktu sampling. (4) Telaah pengaruh bahan organik terhadap struktur kelimpahan fitoplankton dan (5) Telaah pengaruh bahan organik terhadap struktur dan kelimpahan zooplankton dan makrozoobenthos. Analisis keragaman untuk mengevaluasi perbedaan kandungan bahan organik (800) dilakukan menurut zone dan waktu sampling, baik di lapisan permukaan maupun di lapisan dasar. Selanjutnya analisis struktur dan kelimpahan dilakukan dengan cara analisis kuantitas, dan bioekologi.
Keyword: Plankton, Organic matter, Benthos

Judul: Zooplankton Community Structure in Banten Bay to Describe the Health of the Aquatic Environment
Abstrak: Perairan Teluk Banten merupakan wilayah perairan yang dipengaruhi oleh berbagai aktivitas seperti kegiatan industri maupun berbagai aktivitas manusia sehingga dapat dikhawatirkan dapat menyebabkan penurunan kondisi perairan serta perubahan komposisi dan kelimpahan zooplankton. Penelitian ini bertujuan untuk menganalisis kondisi perairan Teluk Banten berdasarkan struktur komunitas zooplankton untuk menggambarkan kesehatan lingkungan perairan. Pengambilan contoh dilaksanakan pada bulan Oktober hingga Desember 2021, meliputi19 stasiun di muara Sungai Berung, muara Sungai Cibanten, muara Sungai Pamong, serta 16 stasiun di perairan laut. Parameter kualitas air yang diukur meliputi suhu, salinitas, kecerahan, dan klorofil-a. Analisis data meliputi kelimpahan zooplankton, indeks keanekaragaman, keseragaman, dan dominansi. Sebaran kelimpahan zooplankton dianalisis menggunakan Surfer 16 (Golden Software). Hubungan klorofil-a dan zooplankton dianalisis menggunakan regresi linear. Zooplankton yang ditemukan selama penelitian terdiri dari 29 genera dan 1 stadia. Zooplankton didominasi oleh Copepoda dan organisme yang mendominasi secara keseluruhan adalah krustasea Nauplius stadia. Kelimpahan zooplankton di perairan Teluk Banten berkisar 13,47–305,09 ind/L. Persebaran zooplankton lebih tinggi di area dekat pantai dan semakin rendah ke arah sisi luar teluk. Struktur komunitas zooplankton memiliki keanekaragaman rendah, keseragaman besar, dan dominansi rendah-sedang. Kelimpahan zooplankton berkorelasi signifikan dengan klorofil-a., Banten Bay is estuary that are affected by various human activities such as industrial and non-industrial activities, which can cause concerns about the decline in water quality conditions and changes in the composition and abundance of zooplankton. This research aims to analyze estuary conditions based on the structure of the zooplankton community to describe the health of the aquatic environment. Sampling and measurements were carried out from October to December 2021 at 19 stations, including the river mouth of Berung River, Cibanten River, Pamong River, and 16 other sea sites stations. Water quality parameters measured include temperature, salinity, water clarity, and chlorophyll-a. Data analysis includes zooplankton species abundance, diversity index, uniformity and dominance. The distribution of zooplankton abundance was analyzed using Surfer 16 (Golden Software). The relationship between chlorophyll-a and zooplankton was analyzed using linear regression. The zooplankton found during the research consisted of 29 genera and 1 stage. Zooplankton community was dominated by Copepods and the Nauplius of Crustacea dominates overall community. The abundance of zooplankton in the Banten Bay ranges from 13.47–305.09 ind/L. The distribution of zooplankton near the coast tends to be higher and lower towards outer side of the bay. The zooplankton community structure has low diversity, great uniformity, and low - medium dominance. The relationship between chlorophyll-a and zooplankton shows that zooplankton abundance can be influenced by chlorophyll-a.
Keyword: zooplankton, abundance, structure community, Banten Bay

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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