Judul: Analysis of Transaction Cost and Impact of Capture Fisheries Fuel Quota Policy in Padang City
Abstrak: Nilai subsektor perikanan terhadap PDRB Kota Padang mengalami peningkatan dari tahun 2017 sampai 2021 seiring dengan peningkatan jumlah nelayan dan peningkatan produksi ikan. Ketersediaan input produksi bahan bakar minyak serta kedekatan akses nelayan pada pasar input merupakan hal penting dalam kegiatan usaha perikanan. Penelitian ini bertujuan untuk mengestimasi penerimaan bersih nelayan setelah adanya kebijakan kuota bahan bakar minyak di Kota Padang, mengestimasi biaya transaksi nelayan dengan dan tanpa kebijakan kuota bahan bakar minyak dan menganalisis dampak kebijakan kuota bahan bakar minyak terhadap keberlanjutan perikanan cakalang di Kota Padang. Analisis yang digunakan adalah analisis penerimaan dan biaya dan analisis bioekonomi. Hasil analisis penerimaan bersih nelayan kapal tonda tahun 2021 dalam satu tahun sebesar Rp 85.097.477. Biaya transaksi yang muncul sebelum adanya kebijakan kuota bahan bakar minyak pada tahun 2021 rata-rata sebesar Rp 405.000 per trip dan sesudah kebijakan kuota bahan bakar minyak, biaya transaksi berkurang secara signifikan menjadi Rp 10.000 per trip. Kebijakan kuota bahan bakar minyak meningkatkan penerimaan nelayan karena berkurangnya biaya transaksi yang dihadapi. Analisis bioekonomi menunjukkan kebijakan ini mengakibatkan kenaikan produksi namun dengan laju yang cukup rendah, sehingga dinilai tidak mengancam kelestarian sumberdaya ikan cakalang di Kota Padang karena produksi tangkap aktual belum melebihi produksi tangkap optimal., The value of the fisheries subsector to the GRDP of Padang City has increased from 2017 to 2021 in line with the increase in the number of fishermen and the increase in fish production. The availability of fuel oil production inputs and the close access of fishermen to input markets are important in fisheries business activities. This study aims to estimate the net income of fishermen after the fuel oil quota policy in Padang City, estimate the transaction costs of fishermen with and without the fuel oil quota policy and analyze the impact of the fuel oil quota policy on the sustainability of skipjack tuna fisheries in Padang City. The analysis used is revenue and cost analysis and bioeconomic analysis. The results of the analysis of net income of tonda boat fishermen in 2021 in one year amounted to IDR 143,895,020. Transaction costs incurred before the fuel oil quota policy in 2021 averaged IDR 405,000 per trip and after the fuel oil quota policy, transaction costs were significantly reduced to IDR 10,000 per trip. The fuel oil quota policy increases fishermen's income due to reduced transaction costs. Bioeconomic analysis shows that this policy results in an increase in production but at a fairly low rate, so it is considered not to threaten the sustainability of skipjack tuna resources in Padang City because actual catch production has not exceeded optimal catch production.
Keyword: fuel oil, bioeconomics, transaction cost, skipjack tuna, fisherman's income

Judul: Catching productivity and biotechnical economic analysis of Danish Seine Net Fishing Units at Palabuhanratu Fishing Port
Abstrak: Volume produksi ikan tongkol di PPN Palabuhanratu tahun 2017 sampai 2021 menunjukkan trend menurun. Salah satu alat tangkap yang menangkap tongkol adalah payang. Penelitian ini bertujuan menganalisis produktivitas penangkapan dan bioteknik ekonomi unit penangkapan payang di PPN Palabuhanratu. Analisis yang dilakukan yaitu CPUE, komposisi hasil tangkapan, korelasi Pearson, dan analisis ekonomi. Penelitian dilakukan di PPN Palabuhanratu, pada bulan April sampai Mei 2022, menggunakan metode observasi dan wawancara. Produktivitas unit penangkapan payang mengalami fluktuasi dan pada tahun 2021 terjadi penurunan sebesar 50% tetapi trend yang dihasilkan masih stabil. komposisi hasil tangkapan payang di antaranya cakalang, eteman, peperek, tongkol lisong, tongkol banjar, dan tongkol abu-abu. Terdapat beberapa jenis ikan dengan volume produksi yang rendah tetapi bernilai ekonomis di antaranya ikan selar bentong, kuwe, dan gulamah. Faktor teknis yang mempengaruhi produksi kegiatan penangkapan adalah lama setting dan hauling, jumlah ABK mempengaruhi waktu yang dibutuhkan untuk melakukan setting dan hauling. Analisis ekonomi dari kelayakan usaha diperoleh keuntungan sebesar Rp79.928.095,00, PP selama tiga tahun delapan bulan, dan ROI sebesar 20,88%, kelayakan investasi menunjukkan nilai NPV sebesar Rp230.766.053,00, nilai IRR sebesar 24,1%, dan nilai Net B/C 1,786 sehingga usaha menguntungkan dan investasi layak dilakukan., The volume of mackerel tuna production at Palabuhanratu Fishing Port in 2017 to 2021 shows declining trend. One fishing gear that catches mackerel tuna is danish seine net. This study aims to analyze catching productivity and biotechnical economic of danish seine net fishing unit at Palabuhanratu. Analysis carried out is CPUE, catch composition, Pearson correlation, and economic analysis. The research was conducted at Palabuhanratu Fishing Port, in April to May 2022, using observation and interview methods. The productivity of danish seine net fluctuates, in 2021 there will be a 50% decrease in productivity, but resulting trend is still stable. The composition of danish seine net catch included skipjack tuna, moonfish, ponyfish, bullet tuna, black skipjack, and longtail tuna. Fish with low production but high economic value include bigeye scad, giant trevally, and leaftail croaker. Technical factors that affect the production of fishing activities are the length of setting and hauling, number of crews affects time needed to setting and hauling. Economic analysis of business feasibility obtained profit Rp79.928.095.00, PP for three years and eight months, and ROI 20,88%, investment feasibility shows NPV value Rp230.766053.00, IRR value 24,1%, and Net B/C value is 1,786, so that business is profitable and investment is feasible.
Keyword: biotechnical economic analysis, catching productivity, danish seine net, mackerel tuna

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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