Results 251 to 260 of about 132,518 (295)

The mathematical model of productivity- and age-structured scientific community evolution

Scientometrics, 1997
The productivity factor is very important at the mathematical simulation of scientific community evolution. In Ref. 1 the productivity index has been incorporated into the model exogenously to formulate the criterion of dynamic optimization of the scientific community age structure. In this paper we are going to include the productivity (as well as the
A. K. Romanov, A. I. Terekhov
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Production models for nonlinear stochastic age-structured fisheries

Mathematical Biosciences, 1984
Die mathematische Beschreibung der Populationsgröße von Fischpopulationen, deren zeitlicher Verlauf nicht nur durch Umwelteinflüsse, sondern auch durch Fischfang beeinflußt wird, ist wegen der wirtschaftlichen Bedeutung der Fischerei von beträchtlichem Interesse; es wurde daher schon eine Reihe von diesbezüglichen Modellen entwickelt.
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Comparison of stock management with production, difference, and age-structured models using operating models

Fisheries Research, 2011
Abstract Management strategy evaluation (MSE) was used to test the assessment and management performance of three assessment methods in combination with harvest control rules. The assessment procedures considered were: the eXtended Survivors Analysis (XSA), the Schaefer production model, and the difference model.
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Age structure or functional response? Reconciling the energetics of surplus production between single-species models and ECOSIM

African Journal of Marine Science, 2004
Whole-ecosystem foodweb models, specifically the dynamic model ECOSIM, contain specific hypotheses for surplus production that differ from traditional single-species management models. Specifically, ECOSIM begins with an assumption that all species are tightly connected and energetic surplus does not arise through fishing, whereas single-species ...
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Simulated comparisons of breeding plans for beef production—Part 1: A dynamic model to evaluate the effect of mating plan on herd age structure and productivity

Agricultural Systems, 1980
Abstract A computer program to simulate beef production is described. The model is based on the principles of industrial dynamics and constructed in the simulation language DYNAMO. This dynamic model is composed of subroutines that simulate herd structure for a cow herd and a production herd composed of calves from the cow herd.
W.R. Congleton, R.E. Goodwill
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Assessment and management of Cape horse mackerelTrachurus capensisoff Namibia based on a fleet-disaggregated age-structured production model

African Journal of Marine Science, 2010
The Cape horse mackerel stock off Namibia is assessed using a fleet-disaggregated age-structured production model including historical International Commission for the Southeast Atlantic Fisheries (ICSEAF) and current data. Data from acoustic biomass surveys, on commercial catch per unit effort and on commercial catch-at-age, were used to estimate ...
Kirchner, C, Bauleth-D’Almeida, G, Wilhelm, MR   +2 more
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Stock assessment and risk analysis for the South Atlantic population of albacoreThunnus alalungausing an age-structured production model

South African Journal of Marine Science, 1995
The South Atlantic population of albacore is assessed by means of an (observation-error) age-structured production model. Relative abundance (cpue) series up to 1993 from the Republic of China, Japan and South Africa are used in the model-fitting process.
A. E. Punt, D. S. Butterworth, A. J. Penney   +2 more
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The Age-Structured Production Model for the south coast rock lobster population

2005
The south coast rock lobster resource is modelled using an age-structured-productionmodel (ASPM).
Johnston, Susan J, Butterworth, Doug S
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Namibian orange roughy age-structured production model assessments and projections for 2006

2006
Updated assessments of the four orange roughy aggregations off Namibia, based upon a maximum penalised likelihood approach which uses all available indices of abundance and reflects the proportion of a stock present at the fishing aggregation each year, are presented, and projections under constant catch levels reported.
Brandão, Anabela, Butterworth, Doug S
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The 2004 age-structured production model assessments and projections for the South Coast rock lobster resource

2004
The assessment conducted in 2003 has been routinely extended, taking account of a further year’s catch, CPUE and catch-at-age data. CPUE shows a continuation of the increase that commenced in 1998. Results are generally more optimistic than those for the 2003 assessment; this is shown to be a result of both the new abundance data now available as well ...
Johnston, Susan J, Butterworth, Doug S
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