Judul: Kajian ekologis pasak bumi (Eurycoma longifolia Jack.) di pusat kajian hutan tropika areal HPH Pt. Siak Raya Timber, Riau
Abstrak: Pasak bumi merupakan tumbuhan obat yang mempunyai banyak kegunaan. Di Indonesia, tumbuhan ini sudah mulai melangka karena penyebarannya yang terbatas (Kalimantan dan Sumatera) dan pemanenan secara langsung dari alam untuk bahan baku industri jamu. Berdasarkan pustaka, penelitian mengenai aspek ekologi pasak bumi belum pernah dilakukan. Diharapkan dari hasil penelitian ini dapat memberikan data dasar ekologi dalam upaya penangka- ran/pembudidayaan dan pelestariannya. Tujuan dari penelitian ini adalah untuk mengetahui karakteristik ekologis dari tumbuhan pasak bumi. Adapun komponen ekologis yang diamati yaitu komposisi jenis tumbuhan penyusun vegetasi, tanah yang mendukung kehidupan vegetasi, kondisi fisiografi lapangan, kondisi iklim, sifat toleransi terhadap cahaya, kondisi populasi serta pengaruh aktifitas manusia. Penelitian dilakukan melalui pengamatan terhadap kondisi tumbuhan pasak bumi dan hubungan semua faktor lingkungan yang diduga berpengaruh terhadap pertumbuhan dan penyebaran jenis tersebut. Hasil analisis faktor- faktor yang diamati disajikan secara deskriptif. Faktor biotik yang mempengaruhi pertumbuhan dan penye- baran pasak bumi adalah komunitas vegetasi hutan, mikro Sorganisme tanah (mikoriza) dan manusia, sedangkan faktor abiotiknya adalah tanah, kondisi fisiografis, mataheri, suhu dan kelembaban. sinar Suhu tempat tumbuh pasak bumi berkisar antara 23,5°C - 34,0°C. Kelembaban berkisar antara 62% - 98%. Pasak bumi didapati tumbuh pada tanah yang miskin hara dengan pH tanah asam sampai sangat asam. Tekstur tanah lempung liat berpasir, lempung berliat dan lempung berpasir. Dengan memanfaatkan mikoriza, tumbuhan ini dapat meningkatkan efektifitas dalam penyerapan unsur hara. Anakan pasak bumi memerlukan naungan, sedangkan pada tingkat belta dan pohon memerlukan banyak sinar matahari secara langsung untuk pertumbuhan diameter, pembentukan cabang dan organ generatifnya..dst
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Judul: Teknik Perbanyakan dan Kekerabatan Genetik Pasak Bumi (Eurycoma longifolia Jack)
Abstrak: Pasak bumi (Eurycoma longifolia Jack) is a shrubs growing wildly in the forests of Southeast Asia and widely used throughout the region because of its medicinal properties. Uncontrolled harvesting of wild-grown trees has led to rapid decrease of natural populations, as well as causing a potential decrease in genetic diversity. The objectives of this research were 1). To get information about propagation technique of pasak bumi by seed and stem cutting and its suitable growing medium and 2). To estimate genetic relatedness of pasak bumi propagated by seed collected from Jambi using RAPD marker. Propagation by seed produced low germination percentage (14-34%) at different media. Seedling planted in pure carbonized rice husk medium produced the best growth variabel on vigority, primary root number, secondary root number, primary root length and secondary root length. Result from stem cutting showed that medium significantly improved secondary root length, while rooting percentage, primary root length and the number of root significantly was affected by Rootone F treatment. Genetic relatedness by RAPD marker showed that pasak bumi propagated by seed has high value of genetic diversity within population (He = 0,3076) and 78,57% all the loci tested were polimorphic, clustering analysis showed that the plant can be grouped into two group.
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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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