Judul: Fishery Resource-Based Business Sustainability Index in Harapan Island, Kelapa Island, and Kelapa Dua Island, Kepulauan Seribu
Abstrak: Kepulauan Seribu memiliki potensi perikanan yang dapat dikembangkan sebagai usaha perikanan. Sumberdaya ikan dan ekosistem memiliki peran penting pada kegiatan usaha perikanan secara keberlanjutan. Tujuan penelitian ini menentukan indeks keberlanjutan usaha berbasis sumber daya perikanan di Pulau Harapan, Pulau Kelapa, dan Pulau Kelapa Dua. Penelitian dilaksanakan pada 29 Agustus - 1 September 2020 dan menggunakan metode survei dan observasi dengan analisis kelayakan usaha, dan multi-criteria analysis. Keberlanjutan usaha perikanan sangat ditentukan oleh daya dukung sumberdaya dan ekosistem. Keuntungan terbesar dalam kegiatan usaha perikanan tangkap dimiliki oleh Pulau Kelapa, diikuti oleh usaha budidaya di Pulau Harapan yaitu Rp 35.886.667 dan Rp 7.660.000 secara berurutan. Usaha perikanan tangkapan ataupun budidaya di lokasi penelitian memenuhi kriteria investasi sehingga layak dilakukan. Skor rata-rata multi-criteria analysis yang didapatkan dalam kegiatan usaha perikanan tangkap di Pulau Kelapa sebesar 3,13 dan usaha perikanan budidaya di Pulau Harapan sebesar 2,53. Berdasarkan skor tersebut, direkomendasikan agar keberlanjutan dari pengembangan investasi kegiatan usaha perikanan tangkap dan budidaya perlu memperhatikan intergrasi dari aspek ekologi, ekonomi, dan sosial., Kepuluan Seribu has fishery potential that can be developed as fisheries business. Fish resources and ecosystems has an important role in sustainable fishery business investment activities. The purpose of this study is to determine the sustainability index of fisheries resource-based businesses in Harapan Island, Kelapa Island, and Kelapa Dua Island. The research was conducted from August 29 to September 1, 2020. The method used in this research is survey and observation method with feasibility study and multi-criteria analysis. Sustainable fisheries business is very much determined by the carrying capacity of resources and ecosystems. Kelapa Island has the biggest profit in capture fisheries business, followed by mariculture on Harapan Island, which is IDR 35,886,667 and IDR 7,660,000 respectively. Capture fishery business or mariculture at the research location meet the investment criteria so that it is feasible to do so. The average score of multi criteria analysis obtained in capture fisheries business activities on Kelapa Island is 3.13 and aquaculture business on Harapan Island is 2.53. Based on this score, it was recommended that the development of investment in sustainable capture fisheries and mariculture activities needs to pay attention to the integrated carrying capacity of the ecological, economic, and social aspects.
Keyword: daya dukung, investasi, keberlanjutan, Kepulauan Seribu, usaha perikanan

Judul: Pola Rezim Pengelolaan dan Pemanfaatan Sumberdaya Ikan Ekor Kuning di Kepulauan Seribu
Abstrak: The objectives of this research were to determine influence activity utilization yellow tail fish resources to biomass value, production and resources rente on actual condition, open access and sustainable; analyze allocation level optimal dynamic yellow tail fish in Kepulauan Seribu sea; determine profit and financial level of yellow tail fish. Survey and purposive sampling was used as the method of the research. Analyze the data using bio technique, bio economic, dynamic model fish resources, degradation, depreciation and financial analyze. The result showed that utilization of yellow tail fish resources on actual condition more bigger than management regime MEY, open access and MSY from standardization to muroami and fish trap. Yellow tail fish resources utilization in Kepulauan Seribu sea had been overfishing in the biology and economy manner. Discount rate 10%-18% for yellow tail fish resources from standardization to muroami resulting in biomass optimal value ranging from 604.05-631.23 ton. Optimal fish production yellow tail fish ranging from 529.14-531.73 ton while optimal effort ranging from 486-505 trip and optimal rente utilization yellow tail fish resources ranging from Rp17,357.02-Rp30,344.01 million so the number of recommendation fishing gears ranging from 130-135 unit whereas allocation optimal level from standardization to fish trap resulting in biomass value ranging from 20,229,982.45-23,367,432.46 ton. Optimal production yellow tail fish ranging from 7,927,098.07-8,336,259.03 ton, optimal effort of yellow tail fish ranging from 5,098-5,462 trip and optimal rente utilization yellow tail fish resources ranging from Rp270,892,356.96-Rp494,709,645.90 million so the number of recommendation fishing gears 440-484 unit and profit in muroami business is Rp384,751,272 per years and R/C value 1.09, the profit in fish trap business is Rp62,640,000 per years and R/C value 1.46. Based on criteria investment muroami business acquired NPV Rp8,980,639.293 whereas fish trap business acquired NPV Rp2,544,075.314 so the both of fishing gears suitable to implementable and amendable but very sensitive to change price BBM (kerosene and solar).
Keyword: Management regime, Utilization regime, Yellow tail fish, Seribu island, Optimal static, Optimal dynamic, Alat penangkapan ikan, Model surplus produksi, Model bio-ekonomi sumberdaya perikanan, Model dinamik sumberdaya perikanan, Koefisien degradasi dan depresiasi, Analisis finansial, Analisis sensitivitas

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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