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: Effectiveness of using Nitrifying Bacteria Pseudomonas sp. and Denitrifying Bacteria Stenotrophomonas sp. on Culture Media of Vannamei Shrimp Litopenaeus vannamei
Abstrak: Aplikasi bakteri nitrifikasi dan denitrifikasi ke media perairan dilakukan untuk meningkatkan kualitas air budidaya. Penelitian ini bertujuan untuk mengukur efektivitas pengaplikasian bakteri nitrifikasi Pseudomonas sp., denitrifikasi Stenotrophomonas sp., serta perpaduan dari bakteri nitrifikasi dan denitrifikasi dalam mengendalikan lingkungan budidaya udang vaname Litopenaeus vannamei. Hewan uji yang digunakan stadia PL 38 dengan ukuran bobot 2,45±0,23 g dan panjang 7,7±0,25 cm. Bakteri Pseudomonas sp. dan Stenotrophomonas sp. yang digunakan di setiap perlakuan sebanyak 150 mL. Penelitian ini terdiri dari empat perlakuan dengan tiga kali pengulangan. Perlakuan yang diujikan menggunakan kode yang terdiri dari perlakuan K (kontrol), N (aplikasi bakteri Pseudomonas sp. di media air), D (aplikasi bakteri Stenotrophomonas sp. di media air), dan ND (aplikasi bakteri Pseudomonas sp. dan Stenotrophomonas sp. di media air). Penambahan bakteri Pseudomonas sp. dan Stenotrophomonas sp. di media air udang vaname mampu memperbaiki kualitas air, meningkatkan kinerja pertumbuhan, dan mempertahankan kondisi udang vaname dari stres. Hasil penelitian terbaik terdapat pada aplikasi perpaduan bakteri nitrifikasi jenis Pseudomonas sp. dan denitrifikasi jenis Stenotrophomonas sp. di media budidaya udang vaname, The application of nitrifying and denitrifying bacteria to water is carried out to improve the water quality of culture media. This study aimed to measure the effectiveness nitrifying bacteria Pseudomonas sp., denitrifying bacteria Stenotrophomonas sp., and combination of nitrifying and denitrifying bacteria application in controlling the environment of vannamei shrimp Litopenaeus vannamei. The animals used PL 38 measuring weight (2,45±0,23)g and length (7,7±0,25)cm. Pseudomonas sp . and Stenotrophomonas sp . bacteria used on treatment as many as 150 ml. The study consisted of four treatments with three replications. The treatments were K (control), N (application of nitrifying bacteria in water media), D (application of denitrifying bacteria in water media), and ND (application of nitrifying and denitrifying bacteria in water media). The addition of nitrifying and denitrifying bacteria in vannamei shrimp water media can improve water quality, increase growth performance, and reduce stress on vannamei shrimp. The best results was application of an integrated bacteria of nitrifying type Pseudomonas sp. and denitrifying bacteria type Stenotrophomonas sp.
Keyword: growth, Litopenaeus vannamei, Pseudomonas sp, Stenotrophomonas sp

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.
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