Judul: Risk Assessment of Commercial Smoked Shark Consumption
Abstrak: Merkuri merupakan jenis logam berat yang dapat memberikan dampak negatif bagi tubuh. Bentuk merkuri yang paling toksik adalah metil merkuri. Ikan hiu memiliki kemungkinan mengandung merkuri yang tinggi akibat biomagnifikasi. Indonesia merupakan salah satu pemasok utama hiu di dunia. Bentuk olahan ikan hiu adalah hiu asap. Pengasapan dapat menghasilkan senyawa polisiklik aromatik hidrokarbon (PAH) yang diantaranya bersifat karsinogen. Penelitian bertujuan menentukan tingkat cemaran merkuri, metil merkuri, PAH, dan menghitung analisis risiko konsumsi hiu asap. Metode penelitian meliputi uji merkuri, metil merkuri dan kandungan PAH pada ikan hiu asap dan penyebaran kuesioner. Seluruh sampel mengandung merkuri dengan 4 sampel yang melebihi ambang batas (1 ppm). Kandungan metil merkuri terdeteksi pada 6 sampel dengan 3 sampel yang melebihi batas (1 ppm). Kandungan PAH pada sampel terdeteksi dengan jumlah yang tidak melebihi batas maksimum. Hasil analisis risiko menunjukkan nilai Hazard Index (HI) >1 yang berarti risiko dari mengonsumsi hiu asap adalah signifikan dan kronis., Mercury is a type of heavy metal that can have a negative impact on the body. The most toxic form of mercury is methylmercury. Sharks are likely to contain high levels of mercury due to biomagnification. Indonesia is one of the main suppliers of shark in the world. The processed form of shark is smoked shark. Smoking can produce polycyclic aromatic hydrocarbon (PAH) compounds, some of which are carcinogens. The study aims to determine the level of mercury, methyl mercury, PAH, and calculate the risk analysis of smoked shark consumption. Research methods included testing mercury, methylmercury and PAH content in smoked shark and distributing questionnaires. All samples contained mercury with 4 samples exceeding the threshold (1 ppm). Methylmercury was detected in 6 samples with 3 samples exceeding the limit (1 ppm). PAH content in the samples was detected with an amount that did not exceed the maximum limit. The results of the risk analysis showed a Hazard Index (HI) value >1, which means that the risk from consuming smoked shark is significant and chronic.
Keyword: heavy metal, hazard index, chronic

Judul: Detemination Heavy Metal Contamination and Species Identification in Shark Products Using DNA Barcoding
Abstrak: Hiu merupakan konsumen tingkat tinggi (apex predator) yang dapat mengakumulasi logam berat melalui sumber makanannya. Hiu olahan yang mengandung logam berat dalam jumlah tinggi dapat membahayakan manusia. Hiu olahan dijual dalam bentuk potongan kecil dan sulit diidentifikasi spesiesnya, sehingga memerlukan metode molekuler berbasis DNA. Penelitian bertujuan menentukan cemaran logam berat pada olahan hiu, mengidentifikasi spesies menggunakan metode DNA barcoding serta menentukan korelasi antar faktor dalam produksi ikan hiu asap di 3 wilayah Pantura. Metode penelitian ini meliputi uji logam berat, isolasi DNA, amplifikasi DNA dengan marka gen COI, sekuensing, dan penyebaran kuesioner. Spesies yang teridentifikasi meliputi C. sealei, C. tjutjot, C. limbatus, S. lewini, dan R. springeri. Kelima sampel mengandung logam berat merkuri terutama spesies C. limbatus dan S. lewini yang jumlahnya melebihi 1 mg/kg. Hiu olahan masih banyak diminati masyarakat Indonesia khususnya wilayah Pantura dengan volume penjualan rata rata lebih dari 1 kuintal per minggu. Pendidikan dan pendapatan produsen berkorelasi positif dengan volume penjualan hiu di wilayah Pantura., Sharks are high-level consumers (apex predators) that can accumulate heavy metals through their food sources. Processed sharks containing high amounts of heavy metals can harm humans. Processed sharks are sold in the market in the form of small pieces, making it difficult to identify the species, requiring DNA-based molecular methods. The aims of the study were to determine heavy metal contamination in processed sharks, to identify species using the DNA barcoding method and to determine the correlation between factors in smoked shark production in 3 regions of Pantura. The research methods included DNA isolation, DNA amplification with COI gene markers, electrophoresis, sequencing, heavy metal testing, and distributing questionnaires. The identified species include C. sealei, C. tjutjot, C. limbatus, S. lewini, and R. springeri. The five samples contained the heavy metal mercury, especially the species C. limbatus and S. lewini whose amount exceeded 1 mg/kg. Processed sharks are still in great demand by the people of Indonesia, especially in Pantura, with an average sales volume of more than 1 quintal per week. The sales volume of sharks is positively correlated with the education and income of producers in the Pantura.
Keyword: amplifikasi, DNA barcoding, logam berat, amplification, heavy metals

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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