Judul: THE EFFECT OF DIFFERENT pH EXPOSURES TOWARD STRESS LEVEL OF Tor douronensis SEEDS (VALENCIENNES, 1842)
Abstrak: Ikan semah (Tor douronensis) adalah anggota dari marga Cyprinidae yang saat ini terancam oleh eksploitasi dan degredasi habitat sehingga upaya domestikasi perlu dilakukan agar pemanfaatan dan restocking dilakukan secara beriringan. Untuk keberhasilan domestikasi, pemeliharaan benih ikan semah membutuhkan kualitas air optimal dimana pH merupakan salah satu faktor kunci dalam pemeliharaan ikan air tawar. Penelitian ini bertujuan untuk menganalisis respon fisiologis benih ikan semah terhadap perubahan pH. Penelitian dilaksanakan pada Juni sampai Oktober 2021 dengan meneliti kualitas air, pertumbuhan, dan darah. Rancangan penelitian yang digunakan adalah Rancangan Acak Lengkap (RAL) dengan empat perlakuan pH berbeda yaitu pH 6, 7, 8, dan 9. Larutan asam nitrat (HNO3) 10% digunakan untuk menurunkan pH, sedangkan larutan natrium hidroksida (NaOH) 0,4% untuk meningkatkan pH. Hasil penelitian menunjukkan sintasan dan pertumbuhan terbaik terjadi pada perlakuan pH 7, sedangkan pH 9 tidak sesuai untuk pertumbuhan dan kelangsungan hidup benih ikan semah. Kondisi stres sebagai respon terhadap pH yang tidak sesuai ditunjukkan oleh meningkatnya konsentrasi kortisol dan penurunan konsentrasi hemoglobin yang terjadi pada perlakuan pH 9., Mahseer fish (Tor douronensis) is a cyprinid family member, threatened by high exploitation and habitat degradation. Therefore, domestication attemps are needed for sustainable utilization, from which harvesting and restocking are equally implemented. For domestication success, mahseer seeds rearing needs optimum water quality, of which pH is among the critical factor for freshwater species. This research is aimed to analyze the physiological response of mahseer fish seeds to pH changes. The research was conducted from June to October 2021 by observing water quality, growth, and blood. The research design was the Completely Randomized Design (CRD) with four different pH treatments; 6, 7, 8, and 9. The solution of 10% nitric acid (HNO3) was used to lower the pH, whereas 0,4% natrium hydroxide (NaOH) was used to increase the pH level. The results showed that the best pH for survival and growth rate was 7, whereas pH 9 was unsuitable and resulted in stress to mahseer seeds. The stress condition caused by inappropriate pH was shown by increased cortisol concentration and a decrease in hemoglobin concentration that occur in the pH 9 treatment.
Keyword: cortisol, mahseer, pH, stress, weight

Judul: Stress Response of Mahseer Tor douronensis (Valenciennes, 1842) Fingerlings on Ammonia Variability
Abstrak: Domestikasi dan budidaya ikan semah (Tor douronensis) sangat diperlukan untuk mempertahankan kelestariannya. Proses ini membutuhkan kondisi lingkungan yang baik untuk mendukung pertumbuhan dari spesies tersebut. Penelitian ini bertujuan untuk mengevaluasi tingkat toleransi benih ikan semah terhadap variasi konsentrasi amonia yang diukur berdasarkan respon stres ikan tersebut. Percobaan skala laboratorium dilakukan dengan tiga perlakuan, yaitu konsentrasi amonia rendah (<0,4 mg/L), sedang (0,4–0,79 mg/L) dan tinggi (0,8–1,3 mg/L). Tiap perlakuan terdiri dari tiga ulangan. Benih ikan semah yang digunakan pada penelitian ini memiliki ukuran panjang 11,18± 0,8 cm dan bobot 14,91±0,1 g. Pengamatan dan analisis data dilakukan terhadap kualitas air, pertumbuhan ikan, dan parameter darah pada ikan. Hasil penelitian menunjukkan bahwa paparan amonia pada kisaran 0,4–1,3 mg/L menyebabkan benih ikan semah mengalami stres yang ditunjukkan dengan pertumbuhan yang menurun, meningkatnya kadar glukosa dan kortisol serta menurunnya kadar hemoglobin. Berdasarkan penelitian ini, dapat disimpulkan bahwa konsentrasi amonia yang dapat ditolerir benih ikan semah yaitu <0,4 mg/L., Domestication and aquaculture of mahseer (Tor douronensis) are essential to maintain its sustainability. These processes require good environmental conditions to support the growth of cultured species. This study aims to evaluate the tolerance level of mahseer fingerlings to various ammonia concentrations based on their stress response. Experimental laboratory trials were conducted with three treatments: low (<0.4 mg/L), medium (0.4–0.79 mg/L), and high (0.8–1.3 mg/L) ammonia concentrations. Each treatment was carried out with three replicates. Mahseer’s fingerlings used in this study have length of 11.18±0.8 cm and a weight of 14.91±0.1 g. Observations and data analysis were carried out on water quality, fish growth, and fish blood parameters. Results showed that ammonia exposure at 0.4–1.3 mg/L caused stress in mahseer fingerlings as indicated by a decrease in growth, increase in glucose and cortisol levels, and decrease in hemoglobin levels. According to this study, it can be concluded that the tolerable concentration of ammonia exposure in mahseer fingerlings is < 0.4 mg/L.
Keyword: Ammonia, Domestication, Fish, Tor douronensis, Stress

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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