Judul: Peningkatan Produksi Ikan Maanvis Pterophyllum scalare dalam Budidaya Sistem Resirkulasi melalui Peningkatan Padat Tebar
Abstrak: Angelfish is one of the freshwater ornamental fish commodities that has a good market opportunity and very easy to maintain, but the production nursery stage is limited by stocking density at 1 fish/liters. This study was aim to determine the best angelfish stocking density in recirculation systems by measuring the production parameters, water quality parameters, fish quality parameter and production efficiency. Stocking density used was 1, 2, 3 and 4 fish/liters. Fish were obtained from Parung Panjang-Bogor, with an average length of 15.025 ± 1.10 mm and average weight of 0.16 ± 0.012 g. It was kept for 40 days in the 20 liter tank volume that are equipped with a recirculation system with filter reef ginger, zeolites and activated carbon. Data taken during the fish culture was in the form of technical parameters, water quality and angelfish quality which would then be associated with the production efficiency. The results showed that treatment of stocking density 1 fish/liter generated the best results in the production parameters of the survival rate of 98.33 ± 2.89%, specific growth rate of 8.83 ± 0.07% and feed efficiency of 56.10 ± 1.60%. The best fish quality parameters achieved by treatment of stocking density 1 fish/liter with the ratio between height with standard length by 0.93 and the quality of the fin of 97%. Parameters of production efficiency was best achieved in the treatment stocking density 4 fish/liters which the value of R/C ratio was 1.67. Water quality in recirculation systems could be maintained at optimum conditions for growth of angelfish to the end of research without doing total water exchange. Based on consideration of production efficiency and aquaculture business purposes, the activities of the angelfish nursery should be done using recirculation system with stocking density at 4 fish/liters for generate higher profits. Future studies are expected to be able to know the limits on the angelfish stocking density at recirculation aquaculture system and relationship quality decreased with increasing fish stocking density.
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Judul: Produksi Ikan Neon Tetra Paracheirodon innesi Ukuran L dengan Padat Tebar 60, 80, 100 Ekor/Liter Menggunakan Sistem Pergantian Air
Abstrak: Increasing stocking density intended for fish production optimization in the culture system which should be accompanied with water management to maintain water quality remains good for support the survival and growth of fish. This study aimed to analyze the production performance of neon tetra rearing with increased stocking density in water exchange system culture. The fish samples used were neon tetra with the initial length of 1.78 ± 0.01 cm. The results showed that the cultivation of neon tetra in aquarium with size of 30 cm x 30 cm x 33 cm with stocking densities of 60, 80 and 100 individuals/liter with water exchange system could reached the L size of fish as targeted. Among the treatments, stocking density 80 fish/liter produce the best production performance, i.e the survival rate was 82.47% which giving profit value as much Rp 10,625,828 per month.
Keyword: water exhcange, density, neon tetra Paracheirodon innesi, ornamental fish

Judul: Invers dari Matriks Tridiagonal Jacobi
Abstrak: Suatu matriks berukuran n×n dinamakan matriks tridiagonal jika untuk . Karya ilmiah ini memberikan algoritma yang mudah untuk menemukan invers ( dari matriks tridiagonal Jacobi yang simetrik dan nonsimetrik. Setiap elemen pada matriks tridiagonal ini adalah bilangan real. Terdapat 3 lema dan 2 teorema untuk menentukan . Lema pertama menunjukkan persamaan utama dalam membuktikan lema-lema dan teorema-teorema selanjutnya. Invers dari matriks yang simetrik dibuktikan oleh lema kedua yang menunjukkan elemen-elemen baris ke- dari . Selanjutnya, lema kedua dilengkapi dengan teorema pertama yang menunjukkan elemen-elemen dengan . Invers dari matriks yang nonsimetrik dibuktikan oleh lema ketiga yang menunjukkan elemen-elemen dengan dan elemen-elemen dengan dibuktikankan oleh teorema kedua.
Keyword: symmetric, nonsymmetric, matrix