Judul: Analysis of the heavy metal Pb and Fe content of  susuh kura (Sulcospira testudinaria) in rivers in Cinangka Village, Bogor Regency
Abstrak: Desa Cinangka merupakan daerah yang tercemar oleh logam berat yang disebabkan oleh kegiatan pembakaran atau peleburan aki bekas. Kualitas logam berat yang terdapat pada sungai di Desa Cinangka akan mempengaruhi kandungan logam berat yang terdapat pada keong. Penelitian mengenai analisis kandungan logam berat terhadap keong susuh kura (Sulcospira testudinaria) di Sungai Desa Cinangka masih sangat minim. Penelitian ini bertujuan untuk menganalisis tingkat bioakumulasi logam Pb dan Fe pada keong susuh kura (Sulcospira testudinaria) di Sungai Desa Cinangka Kabupaten Bogor. Kandungan logam berat Pb dan Fe pada air berkisar antara 0,0497 – 4,1748. Kandungan logam berat Pb dan Fe pada keong susuh kura berkisar antara 10,82 – 3364,62. Bioakumulasi logam berat Pb dan Fe pada keong susuh kura tergolong dalam akumulasi sedang. Hasil meta-analisis menunjukkan bahwa tidak terdapat perbedaan yang signifikan antara rata-rata kandungan logam berat Pb dan Fe pada keong susuh kura dari beberapa negara. Logam berat dapat memengaruhi organisme perairan yang terakumulasi dalam beberapa organ dan dapat memengaruhi kelangsungan hidup dan pertumbuhan, Cinangka Village is an area polluted by heavy metals caused by the burning or smelting of used batteries. The quality of heavy metals found in the river in Cinangka Village will affect the heavy metal content found in snails. Research on the analysis of heavy metal content in snails (Sulcospira testudinaria) in the Cinangka Village River is still very minimal. This study aims to analyze the level of bioaccumulation of Pb and Fe metals in snails (Sulcospira testudinaria) in the Cinangka Village River, Bogor Regency. The content of heavy metals Pb and Fe in water ranged from 0,0497 – 4,1748. The content of Pb and Fe heavy metals in snails ranged from 10,82 – 3364,62. Bioaccumulation of heavy metals Pb and Fe in snails is classified as moderate accumulation. The results of the meta-analysis showed that there was no significant difference between the average content of heavy metals Pb and Fe in snails from several countries. Heavy metals can affect aquatic organisms that accumulate in several organs and can affect survival and growth
Keyword: Logam berat, heavy metal, bioakumulasi, keong susuh kura, bioaccumulation, snail

Judul: Heavy Metal Content of Fe, Pb in Water and Tilapia (Oreochromis niloticus) in Cinangka Village, Bogor District
Abstrak: Perairan yang tercemar oleh logam berat akibat aktivitas antropogenik sangat memungkinkan terakumulasi ke dalam tubuh biota seperti ikan nila (Oreochromis niloticus) yang terdapat di wilayah perairan sekitar Desa Cinangka. Penelitian ini bertujuan menganalisis bioakumulasi kandungan logam berat timbal (Pb) dan besi (Fe) pada ikan nila serta hubungannya dengan kualitas air. Pengambilan sampel dilakukan sebanyak tiga kali pada bulan September 2020. Titik sampling yang dipilih adalah kolam pemancingan ikan yang terdapat di Desa Cinangka. Analisis konsentrasi logam berat dilakukan dengan menggunakan metode Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Parameter kualitas air kolam pemancingan Desa Cinangka masih sesuai dengan baku mutu. Hasil pengukuran kandungan logam Pb pada daging ikan nila berkisar antara 0,32 mg kg-1 hingga 0,4 mg kg-1 dan kandungan logam Fe sebesar 2,18 mg kg-1 hingga 3 mg kg-1. Faktor biokonsentrasi logam Pb termasuk kategori tinggi dan logam Fe termasuk kategori rendah hingga sedang. Waktu pengambilan sampel yang dilakukan tidak berpengaruh secara signifikan terhadap akumulasi logam berat pada ikan nila. Kata kunci: Bioakumulasi, Desa Cinangka, logam berat, Oreochromis niloticus, Waters polluted by heavy metals due to community activities are very likely to accumulate in the body of organism such as tilapia (Oreochromis niloticus) found in the waters around Cinangka Village. This study aims to analyze the bioaccumulation of lead (Pb) and iron (Fe) in tilapia and their relationship with water quality. Sampling was carried out three times in September 2020. The selected sampling point is a fishing pond in Cinangka Village. Heavy metal concentration analysis was carried out using the Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) method. Parameters of water quality of Cinangka Village fishing pond still in accordance with quality standards. The results of measurements of Pb metal content in tilapia ranged from 0.32 mg kg-1 to 0.4 mg kg-1 and Fe metal content was 2.18 mg kg-1 to 3 mg kg-1. Bioconcentration factor of Pb is high category and Fe metal is low to medium category. The sampling time was not significantly affected by the accumulation of heavy metals in tilapia. Keywords: Bioaccumulation, Cinangka Village, heavy metals, Oreochromis niloticus
Keyword: Bioaccumulation, Cinangka Village, heavy metals, Oreochromis niloticus

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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