Judul: Correlation of Consumption Frequency with Species Identity and Heavy Metal Contamination in Processed Smoked Stingray
Abstrak: Ikan pari asap termasuk olahan populer yang meningkat produksinya. Pemanfaatan komoditas yang tinggi berakibat pada status konservasi komoditas pari di Indonesia menurut Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) ataupun International Union for Conservation of Nature (IUCN), dan kesehatan akibat akumulasi logam berat. Penelitian bertujuan mengidentifikasi spesies pada sampel olahan berbasis DNA barcoding dan status konservasi berdasarkan CITES/IUCN, menentukan cemaran logam berat, serta korelasi antara frekuensi konsumsi dengan beberapa variabel terhadap sustainability komoditas dan dampak akumulasi logam berat yang dikonsumsi. Penentuan cemaran dengan ICP OES untuk tembaga dan ICP MS untuk selain tembaga. Spesies yang teridentifikasi adalah Neotrygon kuhlii status Data Deficient dan Maculabatis macrura status Endangered menurut IUCN. Uji logam berat menunjukkan sampel produk tercemar merkuri berada di bawah batas aman konsumsi menurut SNI, namun logam berat lain seperti timbal, kadmium, dan tembaga tidak terdeteksi. Frekuensi konsumsi olahan pari masih tinggi di kalangan masyarakat., Smoked stingray is a popular dish that has led to an increase in production. The high utilization can impact the conservation status of stingrays’ commodity in Indonesia based on Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) or International Union for Conservation of Nature (IUCN). Excessive consumption can also be harmful because ray can accumulate heavy metals. The research aims to identify stingray species based on DNA barcoding, their conservation status based on CITES/IUCN, determine heavy metal contamination and the correlation between the frequency of consumption with several variables related to sustainability and the impact of heavy metal consumed. Heavy metal analysis was determined using the ICP OES for copper and the ICP MS for other than copper. The results are Neotrygon kuhlii with Data Deficient and Maculabatis macrura with Endangered according to IUCN. Heavy metal testing shows that the contaminated product sample is below the safe consumption limit according to SNI, but other heavy metals such as lead, cadmium, and copper are not detected. However, frequency consumption products are still high in the public.
Keyword: DNA barcoding, heavy metals, Maculabatis macrura, Neotrygon kuhlii

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: Penggunaan Metode Homotopi untuk Menyelesaikan Persamaan KdV (Korteweg-de Vries)
Abstrak: Natural phenomena can be explained using nonlinear mathematical models. In this paper, we studied the solution of KdV equation using the Homotopy method. The KdV equation is used for describing both surface and internal waves. One of the solutions is called a solitary wave. The use of homotopy method to solve the KdV equation required a nonlinear operator which was determined by the nonlinear form of the KdV equation itself. Based on this operator, a recursive formula was obtained to get a sequence of the KdV solution. The higher the sequence order of the sequence used, the closer to the exact solution of the KdV equation.
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