Judul: Faktor-faktor Produksi yang Memengaruhi Output Budidaya Udang Vanamei Indonesia
Abstrak: The major expor commodities of Indonesian fisheries is shrimp. Vannamei shrimp is the largest shrimp seeds are stocked in brackish water pond culture. Because of that, this research focuss in Production Factors that Influence the Vannamei Shrimp Aquaculture’s output in Indonesia. This research uses Cobb- Douglass production function approach with analytical methods of engle-granger cointegration and error correction model (ECM). The result are all variables have increasing trend for 1999 to 2012. All variables have a positive and significant impact on Vannamei Shrimp Aquaculture’s output in long term. In the short term, just variabel of fertilizer that hasn’t impact on Vannamei Shrimp Aquaculture’s output. Seed is the highest variable that influence Vannamei Shrimp Aquaculture’s output not only in long term but also in short term. Besides that, returns to scale of vannamei shrimp aquaculture is in the area of Increasing Return to Scale (IRTS).
Keyword: vannamei shrimp, increasing return to scale, Cobb- Douglass production function, error correction model (ECM), Engle-granger cointegration

Judul: Korelasi Kualitas Air dan Kinerja Produksi pada Pembesaran Udang Vaname (Litopenaeus vannamei) di PT Dewi Laut Aquaculture, Garut
Abstrak: Udang vaname (Litopenaeus vannamei) merupakan komoditas unggulan perikanan yang bernilai ekonomis tinggi. Salah satu faktor yang mempengaruhi keberhasilan budidaya udang vaname yaitu faktor kualitas air. Penelitian ini bertujuan untuk menghitung korelasi kualitas air selama pemeliharaan dan kinerja produksi udang vaname di Dewi Laut Aquaculture, Garut, Jawa Barat. Penelitian ini dilakukan dengan pengamatan secara langsung di tambak udang vaname pada tambak pemeliharaan dengan sistem intensif. Metode yang digunakan pada penelitian ini adalah analisis principal component analysis (PCA) dan uji korelasi. Parameter penelitian yang diamati adalah kualitas air (kecerahan, pH, DO, suhu, salinitas, amonia, nitrit, nitrat, alkalinitas, kesadahan, TOM, plankton, dan bakteri), survival rate (SR), average daily growth (ADG), feed conversion ratio (FCR). Hasil uji korelasi menunjukkan parameter nitrit, dan nitrat menjadi parameter yang paling banyak berkorelasi dengan parameter kinerja produksi. Parameter nitrit - 0,414 dan nitrat -0,496 berkorelasi negatif sedang dengan parameter SR. Parameter nitrit dan nitrat sama-sama berkorelasi negatif sedang dengan ADG yaitu masing masing sebesar -0,416 dan -0,424. Sementara itu, parameter nitrit dan nitrat berkorelasi positif sedang dengan parameter FCR yaitu masing-masing sebesar 0,419 dan 0,427., Whiteleg shrimp (Litopenaeus vannamei) is a leading fishery commodity with high economic value. One of the factors that affect the success of vannamei shrimp farming is the water quality factor. This study aims to calculate the correlation of water quality during rearing and production performance of vannamei shrimp in Dewi Laut Aquaculture, Garut, West Java. This study was conducted by direct observation in vannamei shrimp ponds in ponds with intensive system maintenance. The method used in this study was principal component analysis (PCA) and correlation test. The research parameters observed were water quality (brightness, pH, DO, temperature, salinity, ammonia, nitrite, nitrate, alkalinity, hardness, TOM, plankton, and bacteria), survival rate (SR), average daily growth (ADG), feed conversion ratio (FCR). Correlation test results showed that nitrite and nitrate parameters were the most correlated with production performance parameters. Nitrite -0.414 and nitrate -0.496 were moderately negatively correlated with SR parameters. The nitrite and nitrate parameters were both moderately negatively correlated with ADG at -0.416 and -0.424, respectively. Meanwhile, the nitrite and nitrate parameters were moderately positively correlated with the FCR parameter at 0.419 and 0.427.
Keyword: correlation, pond, production performance, shrimp vannamei, water  quality

Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology