Judul: Biological and Economic Evaluation of The Impact of Predators on Oyster Mortality (A Case study in Quiberon Bay, France).
Abstrak: Pacific oysters have been cultured in several country as a result, Crassostrea gigas has become the leading species in world culture, with an estimated production of 4.6 million tons in 2006. France producing around 130 000 tons of the cupped oyster C. gigas annually and a remaining 1 500 tons of the flat oyster Ostrea edulis. Quiberon Bay has a large production of oyster, approximately 15 000 tons annually which contributes to oyster production in France. These small scale industry activities contributes to largely to France economy. Since the year of 2000 and especially 2006, the oyster mortality rates have reached quite unusual, estimated at 60% mortality in a breeding cycle ending in late 2006, according to the response of 51 companies interviewed by the CRC. This mortality brought a great impact on the France's economy. So, in this study, we observed the effects of oyster mortality in terms of biology and economics. The objectives of this study are to analyse RISCO data on oyster mortality, to determine effect of predators on oyster culture, mapping the distribution of different types of predators and to calculate the economic analysis of oyster mortality. RISCO project is conducted by Ifremer with their partners. As present in the study area, this project is held in Quiberon Bay, France and the 15 station’s of oyster culture. The observations of this research have been conducted monthly (8 surveys) in May until December 2010. Each month, there are several analyses of RISCO project which have been done, one of them is analysis oyster growth and mortality (Spat and Adult). In each station, we counted the number of predators (starfishes and gastropods) on the cage and in each bag we calculated the numbers of dead oysters then we took sampling of 30 living oysters for growth and pathology analysis. In each dead oyster, we also observed the boring oyster by oyster drill and parasitism by Polydora. The result of this research showed that there were a potential role of two species of starfishes, Asterias rubens and Marthasterias glacialis and two species of gastropods, Ocenebra erinacea and Ocenebrillus inornatus. Marthasterias glacialis indicated a great impact on mortality of adult oysters. The relation between oyster's mortality and the presence of gastropods depended on time and according to reproductive cycle. Several months show clearly a predation of oysters and others show a concentration of gastropods for spawning. Predators on oyster culture also indicated a great impact in economic value. The economic value on oyster culture model applied in RISCO project shows that BSP was higher than BAP. Based on economic value analysis on RISCO project shows that BSP was higher than BAP. Economic loss in BAP greatly happen in station 2 and 5, approximately €81.28 - €81.83. On the contrary, station 15 indicate has the higher loss in BSP approximately €54.92 or 363 oysters and for the rest, the economic value was varies between €29.67 - €40.30.
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Judul: Production Patterns and Performance Businesses of Pacific Oyster (Crassostrea gigas) Enlargement in Hyogo, Japan
Abstrak: Pola produksi yang dilakukan Yoshida Suisan Company sebelum pengembangan usaha dalam satu tahun dilakukan selama musim semi, dingin, dan gugur dengan total waktu 9 bulan. Perencanaan pengembangan usaha pada perusahaan perlu dilakukan untuk meningkatkan nilai ekonomi perusahaan, untuk itu perlu dilakukannya budidaya tiram pasifik (Crassostrea gigas) sepanjang tahun untuk memenuhi permintaan konsumen. Penelitian ini bertujuan menganalisis perencanaan pola produksi dan kinerja usaha budidaya tiram pasifik di Yoshida Suisan Company, Hyogo, Jepang. Perencanaan pola produksi yang telah dibuat dalam 1 tahun menghasilkan 12 siklus pembesaran tiram pasifik selama musim panas, gugur, dingin dan semi menggunakan 24 karamba. Panen dapat dilakukan sebanyak 4 karamba setiap bulannya di tahun ke-2. Efisiensi waktu selama 4 musim juga membuat peningkatan kapasitas produksi dari 600 ton menjadi 1200 dalam satu tahun, yang berarti ikut berpartisipasi dalam pemenuhan total produksi tiram pasifik Jepang sebanyak 0.81%. Kinerja usaha yang didapatkan setelah perencanaan pola produksi adalah PP 1,78 tahun dan R/C 1,81 yang berarti usaha kegiatan pembesaran tiram pasifik tersebut layak untuk dijalankan., The production pattern carried out by Yoshida Suisan Company before developing the business in one year is carried out during spring, winter and autumn for a total of 9 months. Business development planning for companies needs to be carried out to increase the company's economic value, for this reason it is necessary to cultivate pacific oysters (Crassostrea gigas) throughout the year to meet consumer demand. This research aims to analyze production pattern planning and performance of the pacific oyster cultivation business at Yoshida Suisan Company, Hyogo, Japan. The production pattern planning that was made in 1 year resulted in 12 pacific oyster rearing cycles during summer, autumn, winter and spring using 24 cages. Harvest can be done as many as 4 cages every month in the 2nd year. Time efficiency over 4 seasons also increases production capacity from 600 tons to 1200 in one year, which means participating in fulfilling the total production of Japanese pacific oysters by 0.81%. The business performance obtained after planning production patterns is PP 1.78 years and R/C 1.81, which means that the pacific oyster growing business is feasible to run.
Keyword: business performance, pacific oysters, production patterns

Judul: Cycle Hamilton pada Graf Lengkap, Graf Regular, dan Graf 2-Connected 4-Regular Berorder Kurang dari Sepuluh
Abstrak: Suatu graf disebut graf Hamilton apabila graf tersebut memuat cycle Hamilton, yaitu cycle yang melewati setiap vertex tepat satu kali. Menentukan keberadaan cycle Hamilton pada suatu graf dapat menggunakan syarat cukup yang berupa teorema-teorema yang telah diperkenalkan sejak tahun 1950-an. Beberapa syarat cukup yang dibahas dalam karya ilmiah ini adalah syarat cukup yang berhubungan dengan graf lengkap dan graf regular. Suatu graf lengkap berorder 𝑛������ ≥ 3 dan graf r-regular berorder 𝑛������ ≤ 2𝑟������ + 1 merupakan graf Hamilton, Karena kedua graf tersebut memuat cycle Hamilton. Selanjutnya, syarat cukup tersebut digunakan untuk menentukan keberadaan cycle Hamilton pada graf 2-connected 4- regular berorder kurang dari 10.
Keyword: graf Hamilton, graf regular, graf lengkap, graf 2-connected 4-regular