Judul: Analisis Kualitas Air dan Kinerja Produksi saat Outbreak Berbagai Penyakit di Tambak Intensif Udang Vaname (Litopenaeus vannamei)
Abstrak: Kualitas air berperan penting pada tambak udang terlebih saat terjadinya outbreak penyakit oleh acute hepatopancreatic necrosis disease (AHPND), white feces disease (WFD), dan white spot disease (WSD). Penelitian ini bertujuan menganalisis kondisi kualitas air dan kinerja produksi saat outbreak berbagai penyakit. Penelitian ini dilakukan pada tiga petak tambak aktif, air tandon, dan air buangan. Parameter yang diamati yaitu kinerja produksi dan kualitas air baik komponen fisika, kimia, ataupun biologi. Analisis statistik dilakukan secara deskriptif dengan teknik principal component analysis (PCA) dan klaster k-means. Hasil penelitian menunjukan parameter kualitas air yang diduga sebagai penyebab terjadinya outbreak penyakit yaitu pH, amonium, nitrit, nitrat, alkalinitas, total bacteria count (TBC), total vibrio count (TVC), total yellow vibrio (TYV), total green vibrio (TGV), dan fitoplankton dengan dominansi Cyanophyceae genus Trichodesmium sp. Laju pertumbuhan bobot harian (LPBH) semakin menurun seiring bertambahnya hari budidaya, tingkat kelangsungan hidup (TKH) dan produktivitas yang dihasilkan rendah, serta rasio konversi pakan (RKP) menunjukan nilai yang tergolong baik. Karakterisasi tambak menunjukan air tandon memiliki kualitas air yang baik dibandingkan dengan petak dan air buangan tambak, semakin meningkatnya hari budidaya karakter kualitas air pada petak tambak semakin mendekati air buangan yang memiliki karakter paling buruk diantara semua lokasi sampling., Water quality plays an important role in shrimp ponds especially during disease outbreaks by acute hepatopancreatic necrosis disease (AHPND), white feces disease (WFD), and white spot disease (WSD). This study aimed to analyze water quality conditions and production performance during outbreaks of various diseases. The study was conducted on three plots of active ponds, reservoir water, and waste water. Parameters observed were production performance and water quality in terms of physical, chemical and biological components. Statistical analysis was conducted descriptively with principal component analysis (PCA) and k-means clustering techniques. The results showed that the water quality parameters suspected as the cause of disease outbreak were pH, ammonium, nitrite, nitrate, alkalinity, total bacteria count (TBC), total vibrio count (TVC), total yellow vibrio (TYV), total green vibrio (TGV), and phytoplankton with dominance of Cyanophyceae genus Trichodesmium sp. The daily weight growth rate decreased with increasing days of cultivation, the survival rate and productivity were low, and the feed conversion ratio showed a relatively good value. Pond characterization showed that the reservoir water has good water quality compared to the plots and pond effluent water, the increasing days of cultivation of water quality characters in pond plots are getting closer to the effluent water which has the worst character among all sampling locations.
Keyword: characterization, disease, production performance, vaname shrimp, water quality

Judul: Relationship of Water Quality and Production Performance of Vaname Shrimp (Litopenaeus vannamei) at PT Persada Karya Lestari, Pesawaran Regency, Lampung
Abstrak: Ekspor udang menjadi sumber devisa yang lebih besar dibandingkan dengan ekspor produk perikanan lainnya di Indonesia. Potensi udang yang prospektif diikuti juga dengan permasalahan dalam budidaya yang dapat menyebabkan kegagalan panen akibat penurunan kualitas air. Penurunan kualitas air cepat terjadi pada tambak udang sistem intensif dengan padat tebar yang tinggi. Faktor lain yang berpengaruh pada budidaya udang yaitu adanya agen patogen yang dapat menurunkan tingkat kelangsungan hidup udang vaname. Penelitian ini bertujuan untuk menganalisis hubungan kualitas air dan kinerja produksi pada tambak udang vaname (Litopenaeus vannamei). Parameter yang diukur pada penelitian ini adalah average daily growth (ADG), survival rate (SR), feed conversion ratio (FCR), kualitas air, dan indikator kesehatan udang. Hasil uji korelasi menunjukkan bahwa kualitas air memiliki hubungan terhadap kinerja produksi udang vaname. Parameter kualitas air yang berhubungan terhadap ADG secara signifikan adalah pH pagi, total ammonia nitrogen (TAN), alkalinitas bikarbonat, dan rasio total vibrio count (TVC) dan total bacterial count (TBC). Tidak ada parameter kualitas air yang berhubungan signifikan terhadap SR. Parameter kualitas air yang berhubungan secara signifikan terhadap FCR adalah pH pagi, pH siang, suhu pagi, alkalinitas karbonat, alkalinitas bikarbonat, dan rasio total vibrio count (TVC) dan total bacterial count (TBC). Kata kunci: kinerja produksi, kualitas air, udang vaname., Shrimp exports become a greater source of foreign exchange compared to the export of other fishery products in Indonesia. The potential of prospective shrimp is also followed by problems in cultivation that can lead to crop failure due to decreased water quality. Rapid decline in water quality occurs in intensive system shrimp ponds with high density. Another factor that affects shrimp cultivation is the presence of pathogenic agents that can decrease the survival rate of shrimp vaname. This study aims to analyze the relationship of water quality and production performance in shrimp ponds vaname (Litopenaeus vannamei). The parameters measured in this study are average daily growth (ADG), survival rate (SR), feed conversion ratio (FCR), water quality, and shrimp health indicators. The results of the correlation test showed that water quality has a relationship to the production performance of vaname shrimp. The water quality parameters associated with ADG are significantly the morning pH, total nitrogen ammonia (TAN), bicarbonate alkalinity, and the ratio of total vibrio count (TVC) and total bacterial count (TBC). There are no water quality parameters significantly related to SR. Water quality parameters significantly related to FCR are morning pH, afternoon pH, morning temperature, carbonate alkalinity, bicarbonate alkalinity, and total vibrio count (TVC) and total bacterial count (TBC) ratio. Keywords: production performance, shrimp vaname, water quality.
Keyword: production performance, shrimp vaname, water quality

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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