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: Production Performance and Bussines of Apartment System Soka Crab Farming with Various Acclimatization Techniques
Abstrak: Budidaya kepiting soka dalam boks apartemen dengan recirculated aquaculture system (RAS) masih menggunakan benih hasil tangkapan alam. Lokasi sumber benih dengan kegiatan budidaya seringkali berjauhan, sehingga dibutuhkan pengangkutan yang umumnya dilakukan secara kering, yang dapat menyebabkan kepiting stres. Pascapengangkutan kepiting membutuhkan aklimatisasi sebelum ditebar ke boks apartemen namun informasi mengenai teknik aklimatisasinya masih terbatas. Penelitian ini bertujuan menganalisis respons fisiologis, tingkah laku, kinerja produksi dan usaha budidaya kepiting soka sistem apartemen dengan berbagai teknik aklimatisasi. Penelitian ini menggunakan rancangan acak lengkap (RAL) dengan tiga perlakuan dan tiga ulangan, yaitu perendaman dan aerasi 60 menit (P1), pencipratan 60 menit (P2), serta pencipratan 30 menit dan perendaman 30 menit (P3). Benih kepiting bakau (Scylla serrata) yang digunakan sebanyak 120 ekor berukuran 40-80 g dan dipelihara selama 30 hari dalam boks apartemen RAS. Kepiting diberi pakan ikan selar kuning satu kali sehari (17.00) secara restrictred (5% dari bobot). Kualitas air dijaga melalui penyifonan sisa pakan dan feses. Paramater penelitian yaitu glukosa hemolim, tingkah laku, tingkat kelangsungan hidup (TKH), laju pertumbuhan mutlak bobot (LPMBb), persentase molting, rasio konversi pakan (RKP), revenue/cost (R/C) dan break event poin (BEP). Perbedaan teknik aklimatisasi tidak berpengaruh terhadap TKH dan LPMBb. Persentase molting dan RKP terbaik diperoleh pada P1 dan P3. Respons fisiologis dan tingkah laku terbaik terdapat pada P3. Kinerja usaha pada semua perlakuan mengalami kerugian dengan R/C <1 dan produksi belum mencapai BEP., Farming soft shell crabs in apartment boxes using a recirculated aquaculture system (RAS) still uses fisheries caught seeds. The location of the seed source and farm activities are often far apart, so transportation is required which is generally carried out in dry condition, which can cause stress to the crabs. Post transportation of crabs requires environmental adjustment (acclimatization) before being stocked in apartment boxes, but information regarding acclimatization techniques is still limited. This research aims to analyze the physiological response, behavior, production performance and culture of soft shell crabs in an apartment system using various acclimatization techniques. This research used a completely randomized design with three treatments and three replications, namely 60 minutes of immersion and aeration (P1), 60 minutes of splashing (P2), and 30 minutes of splashing and 30 minutes of immersion (P3). There were 120 mud crab (Scylla serrata) seed each weighing 40-80 g were reared for 30 days in the RAS apartment boxes. The crabs were given yellow trevally fish once a day (17.00) on a restricted basis (5% of weight). Water quality is maintained through siphoning of leftover feed and feces. The research parameters are hemolytic glucose, behavior, survival rate (SR), absolute weight growth rate, molting percentage, feed conversion ratio (FCR), revenue/cost (R/C) and break event points (BEP). Differences in acclimatization techniques have no effect on SR and absolute weight growth rate. The best molting percentage and FCR were obtained at P1 and P3. The best physiological and behavioral responses are found in P3. Business performance in all treatments experienced losses with R/C <1 and production had not reached BEP.
Keyword: acclimatization, apartement box, mud crab, RAS, stress

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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