Judul: Effectiveness of Aquaponic Systems for Catfish (Clarias sp.) Nursery with Different Numbers of Water Spinach (Ipomoea spp.) Plants
Abstrak: Sistem akuaponik adalah teknik polikultur antara perikanan (akuakultur) dan pertanian (hidroponik). Sistem ini dapat menjadi solusi permasalahan limbah organik media air budidaya dan keterbatasan lahan dan air di perkotaan, sebagai urban farming. Kandungan organik yang tidak terkontrol dapat menyebabkan terganggunya kesehatan pada ikan. Kangkung (Ipomoea spp.) menjadi salah satu tanaman akuaponik karena dapat digunakan sebagai biofilter, sehingga jumlah penggunaannya dapat mempengaruhi kualitas air budidaya. Tujuan penelitian ini yaitu mengetahui efektivitas jumlah tanaman kangkung dalam pendederan ikan lele (Clarias sp.) dengan sistem akuaponik terhadap kinerja produksi. Penelitian dilakukan di Laboratorium Manajemen Akuakultur, Departemen Budidaya Perairan IPB serta menggunakan Metode Rancang Acak Lengkap (RAL). Ikan lele dipelihara selama 30 hari dengan sistem akuaponik bersama kangkung (Ipomoea spp.) dengan berbagai jumlah yaitu 30 netpot yang ditempatkan pada rak hidroponik serta tanaman tambahan 45 netpot dan 60 netpot ditempatkan di atas permukaan air budidaya sebagai perlakuan. Masing-masing netpot memiliki 4 bibit tanaman dengan bobot sekitar 20-23 g per tanaman. Ikan lele ukuran panjang rata-rata 8,05±0,42 cm ditebar sebanyak 90 ekor/m2 setelah diaklimatisasi, diberi pakan secara ad satiation (sekenyangnya) dengan frekuensi 3 kali sehari. Ikan lele disampling setiap 10 hari sekali. Jumlah kangkung meningkatkan laju pertumbuhan spesifik ikan lele dan mengurangi total suspended solid (TSS) media air budidaya akuaponik yakni 225±35,35 mg L-1. Peningkatan jumlah tanaman kangkung sebesar 60 netpot dalam sistem akuaponik mengurangi TSS dan meningkatkan pertumbuhan ikan lele., The aquaponics system is a polyculture technique between fisheries (aquaculture) and agriculture (hydroponics). This system can be a solution for organic waste problem in cultivation water media and limited land and water in urban areas, as urban farming. Uncontrolled organic content can cause health problems in fish. Water spinach (Ipomoea spp.) is one of the aquaponic plants because it can be used as a biofilter, so the amount of plant used can affect the quality of water. The aim of this research is to determine the effectiveness of the number of water spinach in catfish (Clarias sp.) nurseries using an aquaponics system on production performance. The research was conducted at the Aquaculture Management Laboratory, Department of Aquaculture IPB and used the Completely Randomized Design (RAL) Method. Catfish were reared for 30 days using an aquaponics system with water spinach (Ipomoea spp.) in various quantities, namely 30 netpots placed on hydroponic racks and additional plants in 45 netpots and 60 netpots placed above the surface of the cultivation water as treatment. Each netpot has 4 plants weighing around 20-23 g each plant. Catfish with an average length of 8.05 ± 0.42 cm were stocked at 90 fish/m2 after acclimatization, fed ad satiation (as much as possible) with a frequency of 3 times a day. Catfish were sampled every 10 days. The amount of water spinach increases the specific growth rate of catfish and reduces the total suspended solids (TSS) in aquaponic cultivation water media, namely 225 ± 35.35 mg L-1. Increasing the number of water spinach by 60 netpots in the aquaponics system reduces TSS and increases catfish growth.
Keyword: specific growth rate, total suspended solid, water quality

Judul: Effect of Addition of Probiotic Bacillus NP5 in  Biofloc System on Growth and Health Status of Catfish Juvenile Clarias sp.
Abstrak: Teknologi bioflok telah diketahui dapat menurunkan kadar amonia pada media pemeliharaan budidaya sistem intensif dan probiotik Bacillus NP5R telah diketahui dapat meningkatkan pertumbuhan dan tingkat kelangsungan hidup melalui peningkatan efisiensi pencernaan dan kesehatan ikan. Penelitian bertujuan mengevaluasi penambahan probiotik Bacillus NP5R pada sistem bioflok dalam meningkatkan kinerja pertumbuhan dan status kesehatan benih lele Clarias sp.. Penelitian menggunakan rancangan acak lengkap (RAL) dengan tiga perlakuan dan tiga ulangan, yaitu ikan dipelihara tanpa aplikasi bioflok dan penambahan probiotik Bacillus NP5R (K), ikan dipelihara dengan sistem bioflok (BF), dan ikan dipelihara dalam sistem bioflok dengan penambahan probiotik Bacillus NP5R (BFP). Larva lele dengan panjang rata-rata 0,83±0,00 cm dan bobot rata-rata 0,02±0,01 g dipelihara dengan padat tebar 300 ekor/akuarium selama 30 hari. Parameter yang diamati meliputi pertumbuhan panjang mutlak, laju pertumbuhan harian, rasio konversi pakan, koefisien keragaman, kelimpahan bakteri Bacillus NP5R , total eritrosit, total leukosit, kadar hemoglobin, kadar hematokrit, dan tingkat kelangsungan hidup. Hasil penelitian menunjukkan bahwa penambahan probiotik Bacillus NP5R dalam sistem bioflok dapat meningkatkan laju pertumbuhan 5%, tingkat kelangsungan hidup 15%, dan status kesehatan benih lele yang menunjukkan hasil terbaik dibandingkan perlakuan lainnya. Penerapan sistem bioflok dengan penambahan Bacillus NP5R diharapkan menjadi alternatif solusi untuk mengurangi limbah amonia pada budidaya ikan lele., Biofloc technology has been known to reduce ammonia levels in aquaculture’s intensive system maintenance media and the probiotic Bacillus NP5R has been known to increase growth and survival rates through improved digestive efficiency and fish health. This study aimed to evaluate the addition of probiotic Bacillus NP5R in the biofloc system in improving growth and health status of catfish juvenile Clarias sp.. This study used a complete randomized design (RAL) of three treatments and three replications, namely fish reared without biofloc system and without addition of probiotic Bacillus NP5R (K), fish reared in a biofloc system (BF), and fish reared in a biofloc system with the addition of probiotic Bacillus NP5R (BFP) within 30 days of treatment. The larvae that used had an average length of 0,83±0,00 cm and an average weight of 0,02±0,01 g with a stocking density of 300 individuals per aquarium. Parameters observed during the study included absolute length growth, daily growth rate, feed conversion ratio, coefficient of diversity, abundance of Bacillus NP5R bacteria, total erythrocytes, total leukocytes, hemoglobin levels, hematocrit levels, and survival rates. The results showed that the addition of the probiotic Bacillus NP5R in the biofloc system can increase the growth rate by 5%, survival rate by 15%, and the health status of catfish juvenile which showed the best results compared to other treatments. The application of the biofloc system with the addition of Bacillus NP5R is expected to be an alternative solution to reduce ammonia waste in catfish farming.
Keyword: Bacillus NP5R, biofloc, Clarias sp., growth, health status

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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