Judul: Kinerja Reproduksi Ikan Nila Oreochromis niloticus pada Media Bioflok
Abstrak: Biofloc technology system (BFT) has been successfully applied for nile tilapia growth, but yet for contribution on reproductive performance. This study aimed to evaluate the effect of the application of BFT on reproductive performance of Oreochromis niloticus. This study used tilapia with an average body weight of 84.56 + 4.81 g. Analysis of variance showed that gonadal somatic index (P <0.05) on day 84, liver somatic index at day 56 (P <0.05), fecundity and larvae production from biofloc treatment is higher than controls. But in egg diameter and survival rate have no effect significantly from BFT application (P<0,05).
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Judul: Feed Utilization and Growth Performance of Nile Tilapia (Oreochromis niloticus) in Different Biofloc System
Abstrak: Biofloc accumulation in rearing media could disturb the feed utilization by the cultured fish. One of the solutions to solve the problems is by using settling tank. This study aimed to compare feed utilization and growth performance of nile tilapia in biofloc system with settling tank and without settling tank. This study use two treatments, i.e. biofloc system with settling tank (Bioras) and biofloc system without settling tank (Control) with three replication for each treatment. Fish was reared in outdoor tarpaulin tanks with a diameter of 3 m and a height of 1,2 m, which was filled with about 5000 L of water. Tilapia with an initial average weight of 100 g was cultured at initial density 5 kg m-3 for 112 days with a partial harvest at day-29. Tilapia was feed with comercial diets (protein content 30,54% and lipid content 4,37%) twice a day to apparent satiation. The result showed that feed utilization and growth perfomance of nile tilapia in bioras is better than control. In conclucion, the addition of settling tank in biofloc system make a better impact in feed utilization and growth performance of nile tilapia (Oreochromis niloticus). Keyword : biofloc, bioras, settling tank, tilapia, Akumulasi bioflok dalam media pemeliharaan dapat mengganggu kemampuan ikan dalam memanfaatkan pakan. Salah satu solusi untuk menangani masalah tersebut adalah dengan penggunaan bak pengendapan. Penelitian ini bertujuan untuk membandingkan tingkat pemanfaatan pakan dan kinerja pertumbuhan ikan nila pada sistem bioflok dengan bak pengendapan dan tanpa bak pengendapan. Penelitian ini menggunakan dua perlakuan, yaitu bak pemeliharaan ikan dengan media bioflok dengan penggunaan bak pengendapan (Bioras) dan bak pemeliharaan ikan dengan media bioflok tanpa penggunaan bak pengendapan (Kontrol) dengan tiga ulangan. Pemeliharaan ikan dilakukan di ruang terbuka (outdoor) menggunakan bak terpal dengan diameter 3 m dan tinggi 1,2 m yang diisi air sebanyak 5000 L. Ikan nila dengan bobot rata-rata awal 100 g dipelihara dengan kepadatan 50 ekor m-3 selama 112 hari dan dilakukan panen parsial pada hari ke-29. Ikan nila diberi pakan dengan pelet komersil (kadar protein 30,54% dan lemak 4,37%) dua kali sehari secara at satiation. Hasil penelitian ini menunjukkan bahwa kinerja pertumbuhan dan pemanfaatan pakan ikan nila pada sistem bioras lebih baik daripada kontrol. Berdasarkan hasil penelitian ini dapat disimpulkan bahwa penambahan bak pengendapan pada sistem bioflok memberikan dampak yang lebih baik pada kinerja pertumbuhan dan pemanfaatan pakan ikan nila merah (Oreochromis niloticus).
Keyword: biofloc, bioras, settling tank, tilapia

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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