Judul: Analysis of Catfish (Pangasius sp.) Farming Agribusiness System in Koto Mesjid Village Kampar Riau Regency
Abstrak: Ikan patin merupakan komoditas unggulan Indonesia dengan prospek bisnis yang berorientasi ekspor. Salah satu wilayah yang mengembangkan budidaya ikan patin di Pulau Sumatera adalah Desa Koto Mesjid Kecamatan XIII Koto Kampar yang merupakan kawasan minapolitan dengan produktivitas panen mencapai 40-50 ton/hari. Tujuan penelitian ini adalah menganalisis kegiatan budidaya ikan patin di Desa Koto Mesjid sebagai subsistem on farm terkait dengan subsistem hulu, subsistem hilir, dan subsistem pendukung. Penelitian ini menggunakan metode studi kasus melalui observasi langsung dan wawancara kepada pembudidaya, UMKM olahan patin, dan pedagang pemasar. Hasil menunjukan bahwa bisnis budidaya ikan patin di Desa Koto Mesjid terdiri dari dua tipe, yaitu produksi untuk ikan salai dengan ratio R/C 1,12 dan produksi untuk ikan konsumsi dengan ratio R/C 1,18. Bisnis ikan patin ini didukung oleh balai pembenihan, pakan mandiri, UMKM pengolahan, dan saluran pemasaran yang terus berkembang dan bertambah jumlahnya serta jasa layanan pendukung yang cukup lengkap tersedia. Peningkatan produksi ikan patin sejalan dengan peningkatan pakan mandiri (R2 = 0,72) dan penambahan jumlah RTP budidaya (R2 = 0,74). Hubungan antara subsistem hulu dan hilir dengan subsistem budidaya mampu meningkatkan volume produksi budidaya di kawasan tersebut., Catfish is Indonesia's leading commodity with export-oriented business prospects. One of the areas that develops catfish farming on the island of Sumatra is Koto Mesjid Village, XIII Koto Kampar District, which is a minapolitan area with harvest productivity reaching 40-50 tons / day. The purpose of this study was to analyze catfish farming activities in Koto Mesjid Village as an on-farm subsystem related to the upstream subsystem, downstream subsystem, and supporting subsystems. This research uses a case study method through direct observation and interviews with cultivators, MSME processed catfish, and marketers. The results showed that the catfish farming business in Koto Mesjid village consisted of two types, namely production for smoked fish with an ratio R/C of 1,12 and production for consumption fish with an ratio R/C of 1,18. The catfish business is supported by hatcheries, independent feed, processing MSMEs, and marketing channels that continue to grow and increase in number as well as fairly complete support services available. The increase in catfish production was in line with the increase in independent feed (R2 = 0,72) and the increase in the number of cultivated FHs (R2 = 0,74). The relationship between the upstream and downstream subsystems with the cultivation subsystem is able to increase the volume of cultivation production in the area.
Keyword: Business, catfish, Koto Mesjid Village, production

Judul: Analysis of the Production Function and Cultivation of Catfish (Pangasius sp.) in Muara Enim Regency
Abstrak: Ikan patin (Pangasius sp.) mengalami kenaikan produksi dari tahun 2017 sampai 2021 sebesar 15,04%. Daerah dengan tingkat produksi ikan patin yang tinggi adalah Sumatera Selatan dan salah satunya di Kabupaten Muara Enim. Beberapa pembudidaya melakukan kegiatan usaha sebagai sumber penghasilan utama, sehingga dipengaruhi oleh keberhasilan usaha. Keberhasilan produksi ditentukan oleh faktor-faktor input yang digunakan. Tujuan penelitian ini adalah menganalisis fungsi produksi dan usaha budidaya patin (Pangasius sp.) di Kabupaten Muara Enim. Penelitian dilakukan dengan metode sensus melalui survey, wawancara, dan dokumentasi kepada pembudidaya ikan patin. Analisis dilakukan dengan menghitung kinerja produksi, fungsi produksi (model Cobb-Douglas) dan analisis usaha. Hasil penelitian menunjukkan adanya perbedaan jenis wadah/kolam yang digunakan meliputi keramba jaring apung, keramba jaring tancap, dan kolam tanah. Produktivitas dari masing-masing wadah/kolam berturut-turut adalah 106,88±21,54 kg/m2 (KJA), 53,01±36,43 kg/m2 (KJT), dan 13,95±4,79 kg/m2 (KT). Rata-rata survival rate pada masing-masing kolam berturut-turut adalah 75,63%, 91,43%, dan 85,4%. Hasil fungsi produksi didapatkan variabel penggunaan input belum menunjukkan nilai yang efisien., Catfish (Pangasius sp.) experienced an increase in production from 2017 to 2021 of 15.04%. Areas with a high level of catfish production are South Sumatra and one of them is in Muara Enim Regency. Some cultivators carry out business activities as the main source of income, so that it is influenced by business success. Production success is determined by the input factors used. The purpose of this research is to analyze the production function and cultivation of catfish (Pangasius sp.) in Kab. Muara Enim. The research was conducted using the census method through surveys, interviews, and documentation of catfish cultivators. Analysis is performed by calculating production performance, production function (Cobb-Douglas model) and business analysis. The results showed that there were differences in the types of containers/ponds used, including floating net cages, fixed net cages, and earthen ponds. The productivity of each container/pond were 106,88±21,54 kg/m2 (KJA), 53,01±36,43 kg/m2 (KJT), and 13,95±4,79 kg/m2 (KT) respectively. Average survival rate in each type of pond respectively were 75.63%, 91.43%, and 85.4%. The result of the production function is the usage variable input has not shown an efficient value and needs optimization on input production.
Keyword: business analysis, catfish, Cobb-Douglas, Muara Enim, Productivity

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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