Judul: Fattening of Mud Crab Scylla serrata Fed with Artificial Feed and Trash Fish
Abstrak: Usaha penggemukan kepiting bakau biasanya menggunakan ikan rucah sebagai pakannya, karena pakan buatan komersial belum ada. Di sisi lain, salinitas air di tambak juga bervariasi. Di musim kemarau, salinitas air tambak sangat tinggi, bisa mencapai 50 ppt. Penelitian ini bertujuan mengetahui pertumbuhan kepiting bakau dengan dua jenis pakan berbeda ikan rucah dan pakan buatan yang dibudidaya di dalam bak dan tambak, masing-masing wadah berisi air salinitas 20-23 ppt dan 35-50 ppt. Setiap perlakuan diulang secara individu sebanyak 20 kali. Hasil penelitian menunjukkan bahwa pemberian pakan buatan mampu mempertahankan kelangsungan hidup, laju pertumbuhan relatif dan rasio konversi pakan yang lebih baik dari penggunaan ikan rucah, baik di dalam bak maupun tambak. Nilai-nilai ke tiga kinerja pertumbuhan tersebut lebih baik saat kepiting dibudidaya di dalam bak dari pada di tambak. Usaha penggemukan kepiting bakau di dalam bak (salinitas 20-23 ppt) menghasilkan pendapatan kotor dua kali lipat lebih tinggi dari usaha penggemukan di dalam tambak (salinitas 35-50 ppt)., Mud crab fattening usually use trash fish as feed, due to the unavailability commercial artificial feed. On the other hand, the salinity of the water in the ponds also varies. During dry season, the salinity of pond water is very high, reaching 50 ppt. This research aims to determine the growth of mud crabs feeding with trash fish and artificial feed which were cultivated in tanks and ponds, each containing water with a salinity of 20-23 ppt and 35-50 ppt. Each treatment was replicated with 20 individuals. The results showed that artificial feed was able to maintain survival, relative growth rate and feed conversion ratio better than using trash fish, both in tanks and ponds. These three growth performance values were better when crabs were cultivated in tanks compared to ponds. Mud crab fattening businesses in tanks (salinity 20-23 ppt) generate twice the gross income compared to fattening businesses in ponds (salinity 35-50 ppt).
Keyword: penggemukan, salinitas, Ikan rucah, kepiting bakau, pakan buatan

Judul: Performance of Soft Shell Crab Production and Cultivation Business in Apartment Systems with Different Seed Sources
Abstrak: Pengembangan budidaya kepiting bakau di kawasan perkotaan (urban aquaculture) menggunakan sistem apartemen dengan resirkulasi air masih membutuhkan benih dari hasil tangkapan alam. Benih dari lokasi penangkapan yang berbeda akan mempengaruhi kelangsungan hidup, pertumbuhan, dan produktivitas kepiting bakau dalam sistem akuakultur, terkait dengan kondisi habitat asal kepiting, cara penangkapan, penanganan dan transportasi hasil tangkapan. Kepiting bakau berukuran 50-120 g sebanyak 90 ekor didatangkan dari Bekasi, Tangerang, dan Subang. Kepiting bakau ditangkap di tambak tradisional dan hutan mangrove menggunakan bubu dan pancingan, lalu ditampung selama 2- 3 jam pada drum plastik, karung, dan boks stirofoam, kemudian diangkut secara kering menggunakan keranjang berukuran 48 × 35,5 × 16,5 cm, selanjutnya diaklimatisasi dengan metode pencipratan dan perendaman. Kepiting bakau kemudian dipelihara dalam sistem apartemen selama 30 hari, dan diberi makan ikan rucah selar kuning sebanyak 2-5 g/ekor secara at satiation satu kali dalam sehari pada pukul 17.00 WIB. Hasil penelitian menunjukkan sumber benih dari Kabupaten Bekasi, Tangerang, Subang tidak berpengaruh terhadap kinerja produksi kepiting soka, yaitu kelangsungan hidup 73,33±5,77%, 70,00±10,00%, dan 50,00±10,00% dengan produksi kepiting soka antara 6,67-33,33%. Hasil penjualan kepiting belum mencapai titik impas, kecuali pada kepiting yang berasal dari Tangerang., Development of mangrove crab cultivation in urban areas (urban aquaculture) using an apartment system with water recirculation still requires seeds from natural catch. Seeds from different fishing locations will influence the survival, growth and productivity of mud crabs in the aquaculture system, related to the conditions of the crab's native habitat, methods of catching, handling and transporting the catch. The 90 mangrove crabs measuring 50-120 g were imported from Bekasi, Tangerang and Subang. Mangrove crabs are caught in traditional ponds and mangrove forests using traps and fishing rods, then stored for 2-3 hours in plastic drums, sacks and styrofoam boxes, then transported dry using baskets measuring 48 × 35.5 × 16.5 cm, then acclimatized by splashing and immersion methods. Mangrove crabs are then kept in an apartment system for 30 days, and fed 2-5 g of yellow trevally trash fish/head at satiation once a day at 17.00 WIB. The results of the research showed that seed sources from Bekasi, Tangerang, Subang Regencies had no effect on the production performance of soft shell crabs, namely survival of 73.33 ± 5.77%, 70.00 ± 10.00%, and 50.00 ± 10.00% with soft shell crab production between 6.67-33.33%. The sales of crabs have not yet reached the break-even point, except for crabs originating from Tangerang.
Keyword: crab catching, molting, survival

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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