scholarly journals Optimum yield of demersal fisheries in Japan's coastal and offshore waters

2020 ◽  
Vol 86 (4) ◽  
pp. 256-256
Author(s):  
EIJI TANAKA
Keyword(s):  
Optimum Yield

Multiattribute Analysis and the Concept of Optimum Yield

1984 ◽  
Vol 41 (9) ◽  
pp. 1393-1406 ◽  
Author(s):  
M. C. Healey
Keyword(s):  
Decision Analysis ◽  
Fisheries Management ◽  
Social Factors ◽  
The United States ◽  
Operational Definition ◽  
Clupea Harengus ◽  
Management Options ◽  
Optimum Yield ◽  
Wide Range ◽  
Skeena River

This paper reviews the origin and operational definition of the optimum yield (OY) concept and demonstrates how techniques of decision analysis can provide an analytical model for OY. The concept of OY was formalized as the guiding principle of fisheries management in the United States and Canada in 1976. The policies of both countries make it clear that a wide range of biological, economic, and social factors are to be taken into account in determining OY. Confusion exists, however, about precisely which of these factors should determine OY in any fishery and what is their relative importance. Uncertainty also exists about how to take biological, economic, and social factors jointly into account as the concept of OY implies one must. Established biological and economic models in fisheries are not adequate for such an analysis because their focus is single- rather than multi-objective. Operational techniques of decision analysis, such as multiattribute utility analysis, are specifically designed to deal with multiobjective problems like OY. I propose that a simple, linear, utility model be used to assess the optimality of alternative yield strategies in fisheries management. I illustrate the application of the model by assessing OY options in the New England herring (Clupea harengus) fishery and the Skeena River salmon (Oncorhynchus spp.) fishery. The advantages of the model are that it is simple and intuitively appealing, that it permits a wide range of types and qualities of data to be incorporated into the evaluation of management options, that it is amenable to sensitivity analysis, and that it is adaptable to a variety of decision rules.

Production of Biodiesel from Desert Date Seed Oil Using Heterogeneous Catalysts

2021 ◽  
Vol 53 ◽  
pp. 180-189
Author(s):  
Saidat Olanipekun Giwa ◽  
Maku Barbanas Haggai ◽  
Abdulwahab Giwa
Keyword(s):  
Reaction Time ◽  
Alternative Fuels ◽  
Heterogeneous Catalysts ◽  
Raw Materials ◽  
Biodiesel Production ◽  
Local Market ◽  
Flat Bottom ◽  
Optimum Yield ◽  
Animal Fats ◽  
Date Seed

In the recent time, there is increasing research in the area of alternative fuels as the exhausts of presently used petroleum-based fuels have been identified to have negative effects on the environment. Fuels produced from plant oils and animal fats have the tendencies of replacing petro fuels since they are renewable in nature. One of these renewable fuels is biodiesel. However, the homogenous catalyst used in biodiesel production has some drawbacks such as difficulty in separation from the fuel, soap formation and corrosiveness of the product mixture. In this work, the use of heterogeneous catalyst sourced from local raw materials (kaolin and eggshell) for the production of biodiesel from oil of desert date seed has been investigated. The kaolin obtained from Alkaleri Mining Site, Bauchi, was calcined in an oven at 800 °C for 3 h. The calcined kaolin was then chemically activated. Also, the eggshell-based catalyst was produced from raw eggshells after washing, drying, grinding, sieving using 0.3 mm sieve size and calcining at 900 °C for 3 h. Furthermore, the oil content of the desert date seed, which was acquired from a local market in Bauchi, was extracted via solvent extraction in a laboratory with a yield of 42%. Then, the biodiesel was subsequently prepared by mixing the oil, methanol and catalyst in a flat bottom flask and heating the mixture for a specified period. The catalyst concentration, methanol to oil ratio and time of reaction were subsequently varied to obtain the best yield. The results obtained revealed that an optimum yield of 29% could be obtained at methanol to oil ratio of 6:1 and a reaction time of 60 min using 1.5 g of eggshell-based catalyst while an optimum yield of 22% was obtained with 0.6 g for kaolin-based catalyst at a reaction time of 60 min and methanol to oil ratio of 4:1. It is recommended that further work should be carried out to improve on the yield of the biodiesel obtained using the heterogeneous catalysts.

scholarly journals 16-Unsaturated C19 3-oxo steroids as metabolic intermediates in boar testis

1972 ◽  
Vol 128 (4) ◽  
pp. 945-952 ◽  
Author(s):  
P. J. Brophy ◽  
D. B. Gower
Keyword(s):  
Prolonged Storage ◽  
Fresh Tissue ◽  
Optimum Yield ◽  
Metabolic Intermediates ◽  
Unsaturated Alcohols ◽  
Testis Tissue

1. The formation of the two 16-unsaturated alcohols 5α-androst-16-en-3α-ol and 5α-androst-16-en-3β-ol from [5α-3H]5α-androst-16-en-3-one has been demonstrated in boar testis homogenates. 2. The optimum yield (23%) of the 3α-alcohol was obtained in the presence of NADPH, whereas that for the 3β-alcohol (74%) was obtained when NADH was the added cofactor. 3. The two alcohols were not interconvertible. 4. Prolonged storage of boar testis tissue at −20°C abolished the ability to form all androst-16-enes except androsta-4,16-dien-3-one from [4-14C]progesterone. 5. The production of 5α-androst-16-en-3-one and the two alcohols from [7α-3H]androsta-4,16-dien-3-one only occurred when fresh tissue was used, whereas reduction of [5α-3H]5α-androst-16-en-3-one was unaffected by storage of testis at −20°C. 6. NADPH was the preferred cofactor for the reduction of androsta-4,16-dien-3-one. 7. The previously established conversion of androsta-5,16-dien-3β-ol into androsta-4,16-dien-3-one was shown to be reversible, NADH and NADPH being equally effective cofactors. 8. Pathways of biosynthesis of 5α-androst-16-en-3α- and 3β-ols, with the C19 3-oxo steroids as intermediates, are presented.

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