Judul: Penentuan Salinitas Optimum untuk Pertumbuhan Benih Kepiting Bakau Scylla serrata dalam Sistem Resirkulasi
Abstrak: One of the abiotic factors that affects the growth and the survival of crabs is salinity. The optimum salinity media will give maximum impact on mangrove crabs because it is related with the osmoregulation process. This study aimed to examine the effect of salinity on the survival rate (SR) and spesific growth rate (SGR) of Mangrove Crab (Scylla serrata) through the reaction of physiological condition. This study consisted of the treatments with the salinity medium 15 ppt (A), salinity medium 20 ppt (B), salinity medium 25 ppt (C), and salinity medium 30 ppt (D). The crab’s maintenance in different salinity gave a significant effect (p < 0.05) on the survival rate of the crabs. The salinity treatments also gave a significant effect (p < 0.05) on the Spesific Growth Rate (SGR) of the crabs. The low level of crab’s stress at salinity 25 ppt was described by the total value of high hemocyte and the low osmotic load so that the salinity 25 ppt was the optimum condition for the crabs.
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Judul: Penentuan pH Optimum untuk Pertumbuhan Kepiting Bakau Scylla serrata dalam Wadah Terkontrol
Abstrak: One of the abiotic factors that affects the growth and the survival of crabs is pH. The optimum pH media will give maximum impact on mangrove crabs because it is related with the osmoregulation process. This study aimed to examine the effect of pH on the survival rate (SR) and spesific growth rate (SGR) of Mangrove Crab (Scylla serrata) through the reaction of physiological condition. This study consisted of the treatments with the pH medium 5, pH medium 6, pH medium 7, and pH medium 8. The crab’smaintenance in different pH gave a significant effect (p < 0.05) on the survival rate of the crabs. The pH treatments also gave a significant effect (p < 0.05) on the Spesific Growth Rate (SGR) of the crabs. The low level of crab’s stress at pH 7 was described by the total value of high hemocyte and the high osmotic load so that the pH 7 was the optimum condition for the crabs.
Keyword: pH., specific growth rate, mangrove crabs, survival rate

Judul: Invers Drazin dari Matriks Toeplitz Singular
Abstrak: Matriks Toeplitz adalah matriks yang setiap unsur pada diagonal utama bernilai sama dan setiap unsur pada subdiagonal yang bersesuaian dengan diagonal utama juga bernilai sama. Matriks singular adalah matriks yang tidak bisa ditentukan inversnya. Akan tetapi, dapat diupayakan untuk ditentukan inversnya menggunakan invers matriks yang diperumum. Invers Drazin merupakan salah satu jenis invers matriks yang diperumum. Pada karya ilmiah ini ditentukan invers Drazin dari matriks Toeplitz singular dengan menggunakan metode Leverrier Faddeev. Kemudian, ditentukan invers Drazin dari matriks Toeplitz singular yang direpresentasikan sebagai penjumlahan segitiga bawah dan segitiga atas matriks Toeplitz berdasar pada teorema Gohberg dan Semencul., Toeplitz matrix is a matrix in with element on the main diagonal has the same value and on the subdiagonal corresponding to the main diagonal also has the same value. Singular matrix is a matrix that has no inverse. However, it can be attempted to determine the inverse using a generalized inverse matrix. Inverse Drazin is a type of generalized matrix inverse. This paper discussed the inverse Drazin for a singular Toeplitz matrix using the Leverrier Faddeev method. Then, the Drazin inverse of the singular Toeplitz matrix which is represented as a sum of products of lower and upper triangular Toeplitz matrix based on Gohberg and Semencul theorem.
Keyword: inverse Drazine, singular Toeplitz matrix