Judul: Keterkaitan Produktivitas Primer dengan Bahan Organik di Tambak Udang Intensif
Abstrak: Kondisi kualitas air yang perlu menjadi perhatian di ekosistem tambak adalah peningkatan bahan organik. Bahan organik tersebut akan mengalami dekomposisi oleh bakteri dan hasilnya yang berupa nutrien akan dimanfaatkan oleh fitoplankton melalui proses produksi primer. Penelitian ini bertujuan menganalisis keterkaitan antara produktivitas primer dengan bahan organik di tambak udang intensif. Penelitian dilakukan pada bulan September hingga Desember 2018. Parameter suhu, kecerahan, salinitas, pH, oksigen terlarut, produktivitas primer diamati secara in situ. Parameter bahan organik, nutrien (nitrit, nitrat, amonia, ortofosfat), rasio C/N dianalisis di laboratorium. Analisis keterkaitan produktivitas primer dengan bahan organik dilakukan menggunakan korelasi Pearson. Hasil penelitian menunjukkan semua parameter masih berada pada kisaran yang aman untuk kegiatan budidaya udang vaname sistem intensif. Produktivitas primer menunjukkan korelasi negatif dengan bahan organik, sedangkan produktivitas primer berkorelasi positif dengan nutrien. Produktivitas primer lebih menunjukkan kedekatan dengan nutrien daripada bahan organik., Water quality conditions that need attention in the pond ecosystem are the increasing of organic matter. The organic matter will be decomposed by bacteria and the results will be utilized by phytoplankton through a primary productivity process. This study aims to analyze the relationship between primary productivity and organic matter in intensive shrimp ponds. The study was conducted from September to December 2018. Temperature, brightness, salinity, pH, dissolved oxygen, primary productivity were observed in situ. While organic matter, nutrients (nitrite, nitrate, ammonia, orthophosphate), and C/N ratio were analyzed in the laboratory. Analysis of the relationship between primary productivity and organic matter was carried out using Pearson correlation. The results showed that all parameters were still in a safe range for the intensive system of vaname shrimp cultivation. Primary productivity shows negative correlation to organic matter, while primary productivity has positive correlation to nutrients. Primary productivity shows more proximity to nutrients than organic matter.
Keyword: organic matter, nutrients, primary productivity, intensive ponds

Judul: Korelasi Kualitas Air terhadap Kinerja Produksi dan Analisis Komponen Utama Produktivitas Udang Vaname (Litopenaeus vannamei) di PT Surya Windu Kartika
Abstrak: Udang vaname adalah komoditas unggulan dalam industri perikanan Indonesia. Budidaya udang vaname yang prospektif tidak luput dari permasalahan yang dapat menurunkan hasil produksi. Kualitas air yang menurun dapat mengakibatkan kematian. Penelitian bertujuan menganalisis korelasi kualitas air serta komponen utama pada budidaya udang vaname unit Badean PT SWK, Banyuwangi, Jawa Timur. Penelitian dilakukan menggunakan 5 kolam dengan padat tebar 96–102 ekor/m2 . Kualitas air yang diamati diantaranya pH, salinitas, suhu, kecerahan, oksigen terlarut, total plankton, NH4, NO2, NO3, PO4, alkalinitas, TOM, total yellow vibrio, total green vibrio, dan total vibrio count. Kualitas air di uji korelasi dengan kinerja produksi dan uji PCA terhadap produktivitas. SR berhubungan negatif signifikan dengan suhu siang, NO2, dan alkalinitas. FCR berhubungan signifikan positif dengan pH pagi, suhu pagi, suhu siang, dan alkalinitas. Sedangkan kecerahan pagi, kecerahan siang, DO malam berhubungan negatif terhadap FCR. Tidak ada kualitas air yang berhubungan kuat dan signifikan dengan ADG. Kualitas air yang terukur masih berada pada kisaran optimal, namun terdapat beberapa parameter yang memiliki kisaran yang berfluktuasi. Hasil PCA menunjukkan 4 PC. Komponen utama pada PC1 ada DO malam (positif), PC2 komponen utamanya TGV (positif), PC3 komponen utamanya ADG (positif), komponen utama pada PC4 adalah NO3 (positif)., Vannamei shrimp is a leading commodity in the Indonesian fishing industry. Prospective vaname shrimp cultivation is not free from problems that can reduce production yields. Decreased water quality can lead to death. This study aims to analyze the correlation of water quality and the main components in the cultivation of vaname shrimp at the Badean unit of PT SWK, Banyuwangi, East Java. The study was conducted using 5 ponds with a stocking density of 96–102 fish/m2. The observed water quality included pH, salinity, temperature, brightness, dissolved oxygen, total plankton, NH4, NO2, NO3, PO4, alkalinity, TOM, total yellow vibrio, total green vibrio, and total vibrio count. Water quality was tested for correlation with production performance and PCA test on productivity. SR was significantly negatively related to daytime temperature, NO2, and alkalinity. FCR was significantly positively related to morning pH, morning temperature, afternoon temperature, and alkalinity. Meanwhile, morning brightness, afternoon brightness, and night DO are negatively related to FCR. There is no water quality that is strongly and significantly associated with ADG. The measured water quality is still in the optimal range, but there are some parameters that have fluctuating ranges. PCA results show 4 PCs. The main components in PC1 is night DO (positive), PC2 isthe main component TGV (positive), PC3 is the main component is ADG (positive), the main component in PC4 is NO3 (positive).
Keyword: correlation, water quality, white shrimp

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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