Judul: Utilization of calcium in aquatic environment for molting proccess and its consequence on giant freshwater prawn growth rate (Macrobrachiumrosenbergii de Man)
Abstrak: The Production of freshwater prawn in several pond cultures are very low due to the low availability of Ca 2+ in water. Calcium has a rate in the deposition of carapace after molting. The objectives of this research is to study the addition of calcium in the media for molting proccess and its consequence on the growth of the giant fresh water prawn.. The experiment used complete randomized desi gn with five treatments of different of Ca(OH) 2 : (0 , 15 , 30 , 45, and 60 mg/L), concentration. Each treatments has three replication . The parameters measured were the concentration calcium of exoskeleton, the period of post molt, molting cycle, daily feed consumption, total feed consumption, growth rate, and feed efficiency. Supplementations of 15-60 mg/L has increased the concentration of the media (25.51-35.22 mg/L) compared to the control (18.53 mg/L). Calcium contents of the exoskeleton were found to be different amongs the levels of Ca(OH) 2 addition (0-60 mg/L) until 20 days postmolt, except on molting. Duration of postmolt of the giant freshwater prawns suppl emented with 0. 15, 30, 45, and 60 mg/L were 17, 15, 12, 13 and 15 days, respectively
Keyword: Molting Cycle, Daily Consumption, Water Quality

Judul: The addition of calcium to increase the survival and growth of juvenile giant freshwater prawn (Macrobrachium rosenbergii de man) on the medium salinity
Abstrak: Mineral calcium plays a role in the process of osmoregulation and the formation of the exoskeleton of shrimp. This study aimed to determine the optimal calcium levels that can support the survival and growth of prawns and evaluate the role of calcium for the survival and growth of prawns on the medium salinity. The study consisted of two steps, the first to determine the range of calcium concentrations. The next steps evaluated the role of calcium on the frequency of molting, osmotic work rate, oxygen consumption rate, growth rate, survival and feed efficiency. This study used a completly randomized design with four treatments and three replications (A.salinity of 4 ppt + 0 mg/L Ca(OH)2 B. salinity of 4 ppt + 25 mg/L Ca(OH)2, C.salinity of 4 ppt + 50 mg /L Ca(OH)2 and D. salinity of 4 ppt + 75 mg/L Ca(OH)2 ). Results showed that adding calcium to the medium salinity can decrease levels of osmotic work and oxygen consumption and increasing the frequency of molting, growth rate, survival rate and feed efficiency. The addition of calcium to the medium salinity with a concentration of 50 mg/L Ca(OH)2) is the best medium for growth of juvenile giant freshwater prawn.
Keyword: 

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