Judul: Depurasi Logam Berat Timbal (Pb) pada Ikan Nila (Oreochromis niloticus) dengan Menggunakan Salinitas yang Berbeda
Abstrak: Heavy metal pollution in the water is one of the limiting factor that also determine the success of aquaculture operation. The purpose of this study was to analyze the influence of salinity with increasing depuration of heavy metals Pb, which accumulate in the flesh, measured the level of oxygen consumption, growth and survival of oreochromis and analyze changes in the kidney due to histopathology gills and exposure to heavy metals. This research was carried out in February-April 2011. This research was carried out in the laboratory of the Bogor agricultural University. Results of research depuration of heavy metals indicates that there are significant differences between all treatments. The best salinity is 20 ppt, where the lowest percentage of heavy metals Pb during the process of depuration 120 hours is 1.21%. One is the level of oxygen consumption charge indicators will fish tilapia low salinity obtained at 0 ppt (0.28 0.05 mgO2/gram of fish/hour) and the highest on the salinity of 8 ppt (0.64 0.02 mgO2/g of fish/day). Low oxygen consumption indicates that the amount of energy used to metabolize a little more so that the portion of energy for greater growth. On experiment depurasi of heavy metals Pb in fish flesh of oreochromis shows response inversely between fish oreochromis growth and changes in salinity, growth pressures oreochromis more decreases the increasing salinity of the medium. The greatest growth reduction is obtained at the treatment of 20 ppt salinity is 11.64± 1.15 gr. based on the observations, the degree of survival of oreochromis high salinity media achieved at 0 ppt, 5 ppt and 10 ppt to reach 100%. Whereas on 15 and 20 ppt salinity ppt respectively reached 86.45% and 83.3%. In addition, observations of the Chemical Physics of water media maintenance which include the temperature, DO, pH and alkalinity showed conditions still favor the growth of oreochromis fish.
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Judul: Analisis Kandungan Logam Berat Pb, Cu, dan Cd pada Ikan Nila (Oreochromis niloticus Linnaeus, 1758) Budidaya di Waduk Cirata, Jawa Barat
Abstrak: Waduk Cirata memiliki potensi yang besar baik dalam bidang ekonomi, maupun ekologi. Meskipun begitu, Waduk Cirata sangat rentan terhadap tekanan akibat aktivitas manusia, baik yang berasal dari dalam perairan waduk maupun dari Daerah Aliran Sungai (DAS) Citarum. Penelitian ini bertujuan menentukan kontaminasi kandungan logam berat timbal (Pb), tembaga (Cu) dan kadmium (Cd) pada ikan nila yang dibudidayakan dan hubungannya dengan kualitas perairan di Waduk Cirata. Konsentrasi logam berat dianalisis menggunakan AAS. Kandungan logam berat tertinggi pada ikan nila adalah Cu pada organ ginjal yakni 7,8 mg/kg. Kandungan logam berat tertinggi pada air yaitu Pb yakni 0,210 mg/L. Nilai Bioconcentration Factor (BCF) pada logam Pb sebesar 0,559, Cu 49,166 dan Cd 1,000. Nilai MTI (Maximum Tolerable Intake) untuk orang dewasa (60 kg) pada logam berat Pb sebesar 16,67 kg/minggu, Cd 0,13 kg/minggu dan Cu 11052,63 kg/minggu. Penelitian menunjukkan bahwa kadar Pb, Cu dan Cd tidak sesuai dengan baku mutu yang telah ditetapkan., Cirata Reservoir is great potential both in the economic and ecological fields. However, this Cirata Reservoir is very vulnerable to pressure due to human activities, both from within the reservoir waters and from the Citarum River Watershed (DAS). This study aimed to determine the contamination of the heavy metal content of lead (Pb), copper (Cu) and cadmium (Cd) in cultivated tilapia and its relationship with the quality of waters in the Cirata Reservoir. Heavy metal concentrations were analyzed using AAS. The highest heavy metal content in tilapia is Cu in the kidney, with concentration 7.8 mg/kg. The highest heavy metal content in water is Pb, with concentration 0.210 mg/L. Bioconcentration Factor (BCF) values of Pb 0.559, Cu 49.166 and Cd 1,000. The MTI (Maximum Tolerable Intake) value for adults (60 kg) for heavy metal Pb is 16.67 kg/week, Cd 0.13 kg/week and Cu 11052.63 kg/week. The research shows that the levels of Pb, Cu and Cd are not in accordance with the established quality standards.
Keyword: Cirata reservoir, heavy metals, nile, MTI, tilapia, water

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