Judul: Kualitas media budidaya dan produksi ikan lele sangkuriang Clarias sp. yang dipelihara pada sistem resirkulasi dengan kepadatan berbeda.
Abstrak: Increasing demand for catfish and the need of anticipation for aquaculture productionadecreasedaasaresultafromashrinkageaofacultivatedaland and deturatio n water quality in catfish media causes catfish cultivation should be done intensively by through improvement of culturing technology, one of them is throught utilization of a recirculation system in order to maintain water quality. Therefore, this experiment will observe at changes of water quality that occur in catfish rearingnponds at different stockingadensity whichausinga recirculation system. The purpose of this experiment was to analyze the changes in water quality, growth, survival and differences in the production growth of Sangkuriang catfish Clarias sp. in the outdoor recirculation system with different stocking density as a base for determining the optimal stocking density. The experimentawasaimplementedafromaAugustato Septembera2011,aatathe Installati on ofaAquacultureaEnvironmental Research and Toxicology, Cibalagung, Bogor. The design of the experiment is Randomized Complete Design with 3 treatments and 3 replications. The treatments include 50 ekor/m2, 100 ekor/m2 dan 150 ekor/m2. Water quality measurements performed on a regular basis, consisting of physical and chemical character of maintenance water media that ware temperature, pH, DO, ammonia, nitrites and nitrates as well as measurement fish biology parameters include, SR, SGR, the absolute growth weight and length. The results showed that different stocking density that used in each treatment produces changes of water quality still within the normal range for rearing Sangkuriang catfish Clarias sp . The treatment that gives the growth, survival and production results of best is the 150 ekor/
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Judul: Effectiveness of Aquaponic Systems for Catfish (Clarias sp.) Nursery with Different Numbers of Water Spinach (Ipomoea spp.) Plants
Abstrak: Sistem akuaponik adalah teknik polikultur antara perikanan (akuakultur) dan pertanian (hidroponik). Sistem ini dapat menjadi solusi permasalahan limbah organik media air budidaya dan keterbatasan lahan dan air di perkotaan, sebagai urban farming. Kandungan organik yang tidak terkontrol dapat menyebabkan terganggunya kesehatan pada ikan. Kangkung (Ipomoea spp.) menjadi salah satu tanaman akuaponik karena dapat digunakan sebagai biofilter, sehingga jumlah penggunaannya dapat mempengaruhi kualitas air budidaya. Tujuan penelitian ini yaitu mengetahui efektivitas jumlah tanaman kangkung dalam pendederan ikan lele (Clarias sp.) dengan sistem akuaponik terhadap kinerja produksi. Penelitian dilakukan di Laboratorium Manajemen Akuakultur, Departemen Budidaya Perairan IPB serta menggunakan Metode Rancang Acak Lengkap (RAL). Ikan lele dipelihara selama 30 hari dengan sistem akuaponik bersama kangkung (Ipomoea spp.) dengan berbagai jumlah yaitu 30 netpot yang ditempatkan pada rak hidroponik serta tanaman tambahan 45 netpot dan 60 netpot ditempatkan di atas permukaan air budidaya sebagai perlakuan. Masing-masing netpot memiliki 4 bibit tanaman dengan bobot sekitar 20-23 g per tanaman. Ikan lele ukuran panjang rata-rata 8,05±0,42 cm ditebar sebanyak 90 ekor/m2 setelah diaklimatisasi, diberi pakan secara ad satiation (sekenyangnya) dengan frekuensi 3 kali sehari. Ikan lele disampling setiap 10 hari sekali. Jumlah kangkung meningkatkan laju pertumbuhan spesifik ikan lele dan mengurangi total suspended solid (TSS) media air budidaya akuaponik yakni 225±35,35 mg L-1. Peningkatan jumlah tanaman kangkung sebesar 60 netpot dalam sistem akuaponik mengurangi TSS dan meningkatkan pertumbuhan ikan lele., The aquaponics system is a polyculture technique between fisheries (aquaculture) and agriculture (hydroponics). This system can be a solution for organic waste problem in cultivation water media and limited land and water in urban areas, as urban farming. Uncontrolled organic content can cause health problems in fish. Water spinach (Ipomoea spp.) is one of the aquaponic plants because it can be used as a biofilter, so the amount of plant used can affect the quality of water. The aim of this research is to determine the effectiveness of the number of water spinach in catfish (Clarias sp.) nurseries using an aquaponics system on production performance. The research was conducted at the Aquaculture Management Laboratory, Department of Aquaculture IPB and used the Completely Randomized Design (RAL) Method. Catfish were reared for 30 days using an aquaponics system with water spinach (Ipomoea spp.) in various quantities, namely 30 netpots placed on hydroponic racks and additional plants in 45 netpots and 60 netpots placed above the surface of the cultivation water as treatment. Each netpot has 4 plants weighing around 20-23 g each plant. Catfish with an average length of 8.05 ± 0.42 cm were stocked at 90 fish/m2 after acclimatization, fed ad satiation (as much as possible) with a frequency of 3 times a day. Catfish were sampled every 10 days. The amount of water spinach increases the specific growth rate of catfish and reduces the total suspended solids (TSS) in aquaponic cultivation water media, namely 225 ± 35.35 mg L-1. Increasing the number of water spinach by 60 netpots in the aquaponics system reduces TSS and increases catfish growth.
Keyword: specific growth rate, total suspended solid, water quality

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
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