Judul: Application of Pumpkin Skin Curcubitaeae Sp. as A Source of Stimulants for Nitrification and Denitrification Processes In Vaname Shrimp (Litopenaeus Vannamei) Culture Environment
Abstrak: Aplikasi tepung kulit labu Curcubitaeae Sp. untuk meningkatkan kualitas air budidaya dan pertumbuhan udang vaname dengan menjadikan sebagai sumber stimulan dalam sistem kekebalan yang dibutuhkan bakteri untuk bertahan pada proses nitrifikasi dan denitrifikasi. Sifat yang cenderung mesofilik dan sumber ion organik untuk pertumbuhan bakteri, kulit labu dapat mendukung pertumbuhan dan aktivitas bakteri nitrifikasi denitrifikasi di lingkungan budidaya. Penelitian ini bertujuan menentukan dosis terbaik tepung kulit labu sebagai bahan biostimulasi untuk pertumbuhan bakteri nitrifikasi denitrifikasi dan mendukung dalam pengelolaan kualitas air serta pertumbuhan udang vaname. Perlakuan yang digunakan yaitu pemberian tepung kulit labu dengan dosis 2%, 4%, 6% per 20 L air dan perlakuan kontrol. Pemberian tepung kulit labu dapat meningkatkan kinerja bakteri dalam proses nitrifikasi dan denitrifikasi. Aktivitas bakteri nitrifikasi terlihat dari adanya nilai ammonia yang relative lebih stabil dibandingkan dengan perlakuan lain. Ammonia paling baik pada perlakuan 6% nitrit paling baik di perlakuan 4%. Perlakuan tepung labu 4% efektif dalam pemeliharaan selama 30 hari yang dapat menjaga kualitas air tetap stabil dan pertumbuhan udang vaname yang meningkat., Application of pumpkin skin flour Curcubitaeae Sp. to improve the quality of aquaculture water and the growth of vannamei shrimp by making it a source of stimulants in the immune system needed by bacteria to survive the nitrification and denitrification processes. The nature of which tends to be mesophilic and a source of organic ions for bacterial growth, pumpkin peel can support the growth and activity of denitrifying nitrifying bacteria in the culture environment. This study aims to determine the best dose of pumpkin skin flour as a biostimulator for the growth of nitrifying denitrifying bacteria and to support the management of water quality and growth of vaname shrimp. The treatments used were pumpkin peel flour with doses of 2%, 4%, 6% per 20 L of water and control treatment. Giving pumpkin skin flour can increase the performance of bacteria in the process of nitrification and denitrification. The activity of nitrifying bacteria can be seen from the presence of ammonia value which is relatively more stable compared to other treatments. The best ammonia in the 6% nitrite treatment the best in the 4% treatment. Pumpkin flour treatment of 4% was effective in maintenance for 30 days which could maintain stable water quality and increase vaname shrimp growth.
Keyword: Curcubitaeae Sp, Litopenaeus Vannamei, Denitrification, Nitrification, Stimulant

Judul: Performa Pertumbuhan dan Vitalitas  Udang Vaname yang Diberi Dosis dan Genus Probiotik Berbeda
Abstrak: Penambahan probiotik pada pakan merupakan salah satu upaya yang dapat dilakukan untuk meningkatkan performa pertumbuhan udang. Penelitian ini bertujuan mengevaluasi pemberian probiotik Bacillus cereus BR2 dan probiotik Staphylococcus lentus L1k yang diberikan melalui pakan dengan dosis berbeda terhadap pertumbuhan dan uji vitalitas udang vaname (Litopenaeus vannamei). Hewan uji memiliki bobot rata-rata 0,19±0,02 g. Penelitian terdiri dari lima perlakuan dengan empat kali ulangan. Perlakuan uji meliputi A (penambahan pakan dengan probiotik BR2 kepadatan 103 CFU ml-1; 1% v/w), B (penambahan pakan dengan probiotik BR2 kepadatan 106 CFU ml-1; 1% v/w), C (penambahan pakan dengan probiotik L1k kepadatan 103 CFU ml-1; 1% v/w), D (penambahan pakan dengan probiotik L1k kepadatan 106 CFU ml-1; 1% v/w), dan kontrol (tanpa penambahan probiotik). Penelitian dilakukan selama 50 hari dan dilakukan sampling setiap 10 hari sekali. Hasil dari penelitian diperoleh nilai pada parameter Survival Rate (SR), Pertambahan Bobot Mutlak (PBM), Laju Pertumbuhan Harian (LPH), Rasio Konversi Pakan (RKP), dan Survival Rate (SR) saat uji respons stres pada perlakuan penambahan probiotik berbeda nyata (P<0,05) terhadap kontrol. Pemberian probiotik BR2 dan L1k melalui pakan dapat meningkatkan kinerja pertumbuhan dan vitalitas udang dengan hasil terbaik pada perlakuan L1k dosis 103 CFUml-1; 1% v/w., The addition of probiotics to feed is one of the efforts that can be made to improve the quality of shrimp. This study aimed to evaluate the administration of probiotics Bacillus cereus BR2 and probiotic Staphylococcus lentus L1k administered through feed with different doses against the growth and vitality test of vaname shrimp (Litopenaeus vannamei). Test animals have an average weight of 0,19±0,02 g. The study consisted of five treatments with four replication. The test treatments were A (addition of feed with probiotic BR2 density 103 CFU ml1 ; 1% v/w), B (addition of feed with probiotic BR2 density 106 CFU ml-1; 1% v/w), C (addition of feed with probiotic L1k density 103 CFU ml-1; 1% v/w), D (addition of feed with probiotic L1k density 106 CFU ml-1; 1% v/w), and control (without the addition of probiotics). The research was conducted for 50 days and sampling every 10 days. Results from the study obtained values on parameters Survival Rate (SR), Absolute Growth Weight (AGW), Specific Growth Rate (SGR), Feed Conversion Rate (FCR), and Survival Rate (SR) during stress response tests on probiotic addition treatments significanly different (P<0,05) to control. Administering probiotics BR2 and L1k through feed can improve the growth performance and viability of shrimp with the best results at L1k treatment dose 103 CFUml-1; 1% v/w).
Keyword: performance growth, probiotics, shrimp vaname, vitality

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
Keyword: