Judul: Performance of gonad development of sea urchin (Tripneustes gratilla) fed artificial diet with different protein level and energy-protein ratio, and estradiol 17-β hormone.
Abstrak: Sea urchin is one of the important marine biota which has economic value. Its gonads fetch high price in many countries. The research was conducted in four phases. The first phase was to study the biological reproduction aspect of sea urchin (Tripneustes gratilla) that catched from Kupang Bay. Ten to thirty individuals were catched every month from May until December 2008. Parameters observed consisted of gonad weight, gonad somatic index, oocyte diameter, gonad colour, test diameter, and body weigth. The second phase was to study gonad development of sea urchin that reared in captivity. Twenty five individuals were reared in tank (2.5 x 2.0 x 1.5 m) and fed macroalga every two days. Parameters such as testosterone and estradiol hormone in gonad and coelomic fluids, gonad weight, and oocyte diameter were measured every two weeks. The third phase was to know the requirement of protein and energy-protein ratio to maximize gonad production and quality. Adult sea urchins were collected from the wild and held in aquarium at laboratory. Nine formulated diet were prepared in order to examine two experimental factors: (1 protein levels (22, 27, and 32%) and (2) energy protein ratio (9, 11, 13 kcalGE/g protein). Gonad weight, protein, total carotenoid, β-carotene, colour, texture, and gonad taste were evaluated at the end of the experiment. The fourth phase was to study the effect of estradiol-17β at dose of 10 and 30 μg/g wet weight of diet for accelerating gonad maturation of sea urchin at different test diameter: 50 – 59, 60 – 69, and 70 – 79 mm. Parameter observed in this experiment were the same as that of the second phase. Result from the first phase showed gonad of sea urchin consisted of five stages of development, namely; developing/recovering, growing, pre mature, mature, and partial spawning. At the second phase, development stages of gonad were the same as observed at the first phase, gonad maturation achieved maximum at 9th week. At the third phase, the 32% protein level and 9 kcal GE/g energy-protein ratio gave higher production and gonad quality. At the fourth phase, estradiol-17β at dose 30 μg could accelerate gonad maturation of sea urchin at the 60 – 69 mm test diameter. Gonad maturation achieved maximum at 7th week. As conclusion, application of 32% protein and 9 ccal GE/g energy-protein ratio, as well as estradiol-17β could maximize gonad performance.
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Judul: Macroalgae development as feeding stimulants for the adult sea urchin (Tripneustes gratilla Linnaeus 1758)
Abstrak: Development of artificial feed for somatic growth and gonad quality is one of the focus of research on sea urchin aquaculture activities. Palatability is important factor when developing artificial feed for aquaculture diets. This study investigated the effects of macroalgae (Sargassum polycystum, Gracilaria lichenoides, and Ulva reticulata) as feeding stimulants to artificial diets consumption and gonad profile for the adult sea urchin Tripneustes gratilla, by three feeding trials. Previously starved T. gratilla were held in replicated (3X) 50 L aquaria with recirculation water system (in the first feeding trial) and flow through water system (in the second and third feeding trial). In the first feeding trial, preference of T. gratilla for dried macroalgae was assessed in choice feeding experiment. T. gratilla displayed significant preference for the agar containing dried U. reticulata at 20% agar weight over nine other diets treatment when they were offered simultaneously. Total protein, energy and the ratio of protein to energy in the dried macroalgae had no correlation on agar consumption by T. gratilla. Three artificial diets were made by incorporating one of each of these dried macroalgae at 5% feed weight used in the second feeding trial. Although no significant difference in artificial diets containing dried macroalgae, urchins fed diets containing dried macroalgae consumed more than basal diet when they were offered as single diet. These results indicate that dried macroalgae added to the artificial diets act as feeding stimulants and increasing the acceptability of artificial sea urchin diets. The third feeding trial used dried U. reticulata as feeding stimulant to artificial diet. Data suggest that artificial diet containing 10% dried U. reticulata boosting feed consumption and significantly increasing nutrient accumulation, gonad index, egg diameter and fix gonad color.
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Judul: Kombinasi algoritma sha 1 dan algoritma rsa untuk membentuk tanda tangan digital
Abstrak: Tanda tangan digital termasuk ke dalam teknik kriptografi yang memanfaatkan teknologi kunci publik (enkripsi asimetris). Tanda tangan digital dapat dibuat dengan mengkombinasikan teknik hashing (untuk membentuk message digest dari pesan asli) dan enkripsi asimetris (untuk membentuk kunci publik dan kunci privat). Teknik hashing yang digunakan adalah teknik rashing satu arah dengan menggunakan algoritma SHA 1, sedangkan algoritma RSA digunakan untuk enkripsi asimetris Tulisan ini bertujuan untuk mempelajari, menganalisis, dan mengimplementasikan pembentukan dan verifikasi tanda tangan digital menggunakan dua metode, yaitu dengan mengkombinasikan algoritma SHA 1 dan algoritma RSA dan dengan menggunakan algoritma RSA saja. Analisis yang dilakukan pada kedua algoritma ini meliputi analisis algoritma, dan analisis hasil implementasi. Analisis terhadap algoritma SHA | menunjukkan bahwa algoritma ini memiliki kompleksitas O(n) untuk kasus terburuk. Sedangkan untuk pembentukan kunci publik dan kunci privat dengan algoritma RSA diperlukan beberapa algoritma pendukung, yaitu algoritma Miller Rabin, Witness, Euclid, dan Extended Euclid. Semua algoritma pendukung tersebut memiliki kompleksitas waktu yang sama, yaitu O(k), dengan adalah panjang representasi bit bilangan bulat. Kompleksitas waktu yang didapatkan untuk proses pembentukan tanda tangan digital dengan kedua metode ini adalah sama yaitu O(nk). Untuk proses verifikasi, kompleksitas waktu yang didapatkan dengan menggunakan kombinasi dua algoritma adalah O(1 + k) dan untuk algoritma RSA adalah O(n + k). Pada proses pembentukan tanda tangan digital menggunakan kombinasi dua algoritma yang ditandatangani adalah message digest yang dihasilkan oleh algoritma SHA 1, sedangkan pada algoritma RSA yang ditandatangani adalah pesan itu sendiri. Dari hasil implementasi didapatkan untuk proses pembentukan tanda tangan digital menggunakan kombinasi dua algoritma lebih cepat dibandingkan dengan menggunakan algoritma RSA saja untuk file-file yang berukuran besar, dst
Keyword: Tnda Tangan Digital, Teknik Kriptografi, Enskripsi Asimetris