Judul: Effects of Electricity Reduction on RAS (Recirculating Aquaculture System) Farming of Eels Monopterus albus
Abstrak: Berkembangnya teknologi budidaya belut Monopterus albus dalam air memungkinkan menggunakan sistem resirkulasi (RAS) yang hemat lahan dan air. Teknologi RAS memerlukan energi listrik selama prosesnya. Upaya untuk mengurangi penggunaan listrik dapat dilakukan penghentian sementara aliran air mengingat belut merupakan spesies air-breather. Tujuan penelitian ini adalah menganalisis efek penghentian secara berkala resirkulasi air dalam sistem RAS terhadap kelangsungan hidup dan status fisiologis belut (Monopterus albus). Perlakuan yang diuji adalah penghentian resirkulasi air pada RAS belut selama 0 jam (A), 6 jam pada siang hari (B), 12 jam pada siang hari (C), 18 jam pada siang sampai pagi hari (D), dan 18 jam pada malam sampai sore hari (E). Selama 60 hari pemeliharaan, belut diberi pakan berupa cacing darah beku sebanyak 2% dari total biomassa. Hasil menunjukkan bahwa penghentian resirkulasi air yang semakin lama tidak mempengaruhi kelangsungan hidup belut dengan kisaran 39,67 – 62,13%. Namun berdasarkan respons fisiologis kondisi belut lebih baik pada penghentian 6 jam sehingga dapat dilakukan penghematan listrik 25% pada budidaya belut dalam sistem RAS., The development of cultivation technology allows the rearing of eels Monopterus albus in water using a recirculation system (RAS) that saves land and water. RAS technology requires electrical energy during its process. Efforts to reduce electricity usage can be done by temporarily stopping the flow of water considering that eels are an air-breather species. The aim of this study was to examine the effects of periodic cessation of water recirculation in RAS on eel survival and its physiological status. The treatments tested were water flow stoppage on RAS for 0 hours (A), 6 hours (B), 12 hours (C), 18 hours at noon to early morning (D), and 18 hours at night until afternoon (E). During 60 days of rearing eels, the eels were fed on frozen blood worms as much as 2% of the total biomass. The results showed that the treatments did not affected on survival rate of the eel. However, based on the physiological response of the eel's blood, the eels were in better condition at six hours of stoppage so that electricity savings of 25% can be made in eel cultivation in the RAS system.
Keyword: air breather species, Monopterus albus, periodic water stoppage, recirculation system

Judul: Production Efficiency of Eel (Anguilla bicolor bicolor) Culture with Recirculation System by the Application of Probiotics in Water and  Feed
Abstrak: Budidaya ikan sidat dengan sistem resirkulasi merupakan upaya meminimalkan penggunaan lahan dan air, namun belum dapat mengatasi masalah penurunan kualitas air dan kinerja produksi ikan. Penambahan probiotik pada pakan dapat meningkatkan kerja metabolisme ikan dan berpotensi untuk memperbaiki kualitas air. Penelitian ini bertujuan untuk menganalisis efisiensi budidaya ikan sidat (Anguilla bicolor bicolor) segmen pendederan menggunakan sistem resirkulasi dengan aplikasi probiotik pada air dan pakan. Penelitian ini menggunakan rancangan acak lengkap (RAL) yang terdiri atas empat perlakuan dengan tiga ulangan. Perlakuan yang digunakan adalah pemberian probiotik secara kombinasi pada air dan pakan dengan dosis masing-masing 7,5 mL L-1dan 15 mL kg-1(A), 7,5 mL L-1 dan 30 mL kg-1 (B), 7,5 mL L-1 dan 60 mL kg-1 (C), serta tanpa pemberian probiotik (K). Ikan yang digunakan pada penelitian ini adalah elver ikan sidat berbobot rata-rata 14,45±0,42 g dan panjang rata-rata 20,8±0,52 cm yang dipelihara selama 60 hari. Efisiensi produksi budidaya ikan sidat terbaik diperoleh pada penambahan probiotik pada air 7,5 mL L-1 dan pada pakan 60 mL kg-1, Recirculation aquaculture system in eel farming could minimized land and water use, but there is still problem on water quality degradation which affects production performance of the fish. Probiotic addition to fish feed could improve fish metabolism and also could maintain water quality. This research aims to analyze the efficiency of eel (Anguilla bicolor bicolor) elver production in the recirculation system with probiotic application on water and feed. This research used a complete randomized design (RAL) consisting of four treatments with three repeats. The treatment that used is the addition of probiotic combination on water and feed at doses of 7.5 mL L-1 and 15 mL kg-1 (A), 7.5 mL L-1 and 30 mL kg-1 (B), 7.5 mL L-1 and 60 mL kg-1 (C), and without probiotic addition both in water and in feed (K). The fish used in this research were eel elver with average weight of 14.45±0.42 g and average length of 20.8±0.52 cm cultured for 60 days in the recirculation system. The best efficiency of eel elver culture production was shown on the addition of probiotic combination on water and feed at doses of 7.5 mL L-1 and 60 mL kg-1 respectively..
Keyword: Anguilla bicolor bicolor, production efficiency, probiotic, recirculation system

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
Keyword: