Judul: Keanekaragaman Cendawan Mikoriza Arbuskula (CMA) di Hutan Pantai Ujung Genteng, Sukabumi-Jawa Barat
Abstrak: Indonesia is one of the countries that has a megadiversity of microorganisms and has a large area of coastal forests. However, research on microbial diversity particularly AMF as one of the dominant microbes in a coastal forest ecosystems has not been done extensively. The main objective of this research was to study the diversity and distribution of AMF in coastal forest and to analyse effects of salinity on the fungal and plant community at Coastal Forest Ujung Genteng Cape, Sukabumi - West Java. This research was carried out in two parts: field, green house and laboratorium experimental activities. Field experimental activities were conducted for vegetation analysis, collecting of plant root system, rhizosphere soils from tree and pole phase,. seedling of understorey plants for fungal colonization analysis, isolation and identification of AMF and soil characteristics, include salinity. Green house and laboratorium activities were carried out for isolation, identification and colonization analysis of AMF. Field research location was divided into three zones, first zone was 0 – 70 m distance from coastal area (P), second zone was 71 – 140 m distance from coastal area (T), and third zone was 141 m distance from coastal until forest up to area in the center (H). Twenty three AMF species from 45 plant rizosphere were identified. The fungi belong to 5 species of Acaulospora, 2 species of Gigaspora, 13 species of Glomus, 1 species of Paraglomus and 2 species of Scutellospora. Glomus geosporum was the most dominant AMF in the ecosystem with the value of frequency was 16.49% - 23.67%. Glomus etunicatum, Acaulospora foveata, A. longula, A. scrobiculata, A. tuberculata, and Scutellospora auriglobosa were the AMF that had frequency higher than other species but less than G. geosporum in the field. Results from vegetation analysis indicated that Ujung Genteng Coastal Forest had 68 plant species belonging to 40 families. Dysoxylum parasiticum and Piper cf. baccatum were dominant plants in the ecosystem. The plant community measured at the three zones experimental sites were differed. The similarity index value of the plant community (Is) between coastal P) and center (T) area was 35.42%, between center (T) and forest center (H) was 32.53%, and between coastal edge (P) and forest center (H) was 27.04%. There was no correlation between diversity of plant and diversity of AMF onserved. Diversity of AMF were influenced with all interaction environment factors especially salinity. Two species of AMF had a narrow distribution and found only in a rhizosphere of one plant species . Glomus sp 5. found only in Guettarda speciosa rhizosphere and Glomus sp6. in Salacia sp. rhizosphere. Nineteen species were identified from P zone, 17 species from T zone and 14 species from H zone, with the index diversity values of AMF were 0.73 – 6.64, 0.85 – 4.93 and 1.26 – 4.84, respectively. The salinity at Ujung Genteng Cape was falled in moderate degree with the value of 420 – 1735 μs/cm. The salinity influenced the diversity of AMF and plant community structures. Nineteen species were identified from P zone, 17 species from T zone and 14 species from H zone,
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Judul: Keanekaragaman Fungi Mikoriza Arbuskula Berdasarkan Gradien Salinitas di Hutan Pantai Taman Nasional Baluran, Jawa Timur
Abstrak: Mikoriza merupakan simbiosis mutualisme antara fungi dengan perakaran tanaman. Penelitian ini bertujuan untuk mengidentifikasi keberagaman genus kelompok Fungi Mikoriza Arbuskula (FMA) serta hubungannya dengan sifat-sifat tanah, khususnya gradien salinitas di tegakan hutan pantai Perengan Taman Nasional Baluran, Jawa Timur. Prosedur kerja dalam penelitian ini meliputi pengambilan sampel, penghitungan kepadatan spora, isolasi dan identifikasi genus FMA, kuantifikasi kolonisasi FMA, serta penentuan sifat kimia tanah. Kepadatan spora di tanah salin hutan pantai TN Baluran tidak memiliki korelasi dengan gradien salinitas (3‰, 2.5‰, 2‰, 1.5‰ dan 1‰) dan jarak sub plot pengamatan dari garis pantai. Kepadatan spora lebih dipengaruhi oleh faktor genangan dan jenis tanaman sampel. Selain itu gradien salinitas juga tidak memberikan pengaruh terhadap tinggi rendahnya persen kolonisasi FMA. Ditemukan tiga genus FMA (genus Glomus, Acaulospora, dan Gigaspora) dengan genus Glomus sebagai genus yang paling mendominasi. Tanah hutan pantai Taman Nasional Baluran tergolong subur yang ditandai oleh nisbah C/N sedang hingga tinggi. Kandungan P tersedia dalam tanah sampel memberikan pengaruh negatif terhadap kolonisasi mikoriza.
Keyword: FMA, genangan, keanekaragaman, salinitas, tanaman

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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