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| Registros recuperados: 22 | |
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| Tisdell, Clement A.. |
| Discusses concepts of competition in economics and ecology and the relevance of evolution to both subjects. It is suggested that although speciation or increasing biodiversity tends to occur in undisturbed ecological systems, the opposite trend may occur in economic systems. Competition based on optimisation plays a significant role in theories of the evolution of species and some theories of the evolution of business or industrial structures. But evolution does not result in optimal selection of species or businesses for the future, and there is scope for doubt about what is being optimised by survivors in the evolutionary process. Ecological or biological theories of intra-specific competition involving scramble and contest competition are outlined and... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Biology; Competition; Evolution; Market development; Optimisation; Environmental Economics and Policy. |
| Ano: 2001 |
URL: http://purl.umn.edu/48384 |
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| Alemán Morales, Mireya. |
| La producción de “setas” (Pleurotus ostreatus), es una alternativa para producir y diversificar los alimentos que requiere la población en México. En el país es escasa la información acerca de la rentabilidad de éste cultivo. Por ello, el objetivo de este trabajo fue estimar una función de producción que muestre matemáticamente la relación funcional entre los insumos productivos utilizados y la producción “setas”. La variable dependiente la constituyó la producción de “setas” producidas y la variable independiente fueron las bolsas en producción. Los resultados económicos mostraron que la etapa de producción II, la que es económicamente relevante, se inicia en el punto donde se encuentran en el área de producción 2449 bolsas y termina donde el producto... |
| Tipo: Tesis |
Palavras-chave: Función de producción; Pleurotus ostreatus; Optimización; Rentabilidad; “setas”; Production function; Pleurotus ostreatus; Optimisation; Viability; “mushrooms”. |
| Ano: 2008 |
URL: http://hdl.handle.net/10521/1417 |
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| Chalak, Morteza; Pannell, David J.. |
| Weeds can cause significant problems to natural ecosystems. Although there have been numerous studies on the economics of weed control, relatively few of these studies have focused on natural ecosystems. This paper addresses this gap in the literature by assessing the cost-effectiveness of a comprehensive range of control strategies for blackberry (Rubus anglocandicans) in natural environments in Australia. We developed a stochastic dynamic simulation model and a deterministic dynamic optimisation model. The stochastic model calculates the expected net present value (NPV) of a range of control strategies, including any combination of treatment options. The optimisation model identifies the treatment combination that maximises NPV. Both models represent the... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Environment; Economics; Weed; Stochastic; Optimisation; Management; Environmental Economics and Policy. |
| Ano: 2011 |
URL: http://purl.umn.edu/108416 |
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| Chalak-Haghighi, Morteza; Pannell, David J.. |
| Weeds can cause significant problems to natural ecosystems. Although there have been numerous studies on the economics of weed control, relatively few of these studies have focused on natural ecosystems. This paper addresses this gap in the literature by assessing the cost-effectiveness of a comprehensive range of control strategies for blackberry (Rubus anglocandicans) in natural environments in Australia. We developed a stochastic dynamic simulation model and a deterministic dynamic optimisation model. The stochastic model calculates the expected net present value (NPV) of a range of control strategies, including any combination of treatment options. The optimisation model identifies the treatment combination that maximises NPV. Both models represent the... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Environment; Economics; Weed; Stochastic; Optimisation; Management; Environmental Economics and Policy. |
| Ano: 2010 |
URL: http://purl.umn.edu/58886 |
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| Chalak, Morteza; Pannell, David J.; Polyakov, Maksym. |
| Invasive species are significant threats to biodiversity, natural ecosystems and agriculture leading to large worldwide economic and environmental damage. Spread and control of invasive species are stochastic processes with important spatial dimensions. Most economic studies of invasive species control ignore spatial and stochastic aspects. This paper covers this gap in the previous studies by analysing a spatially explicit dynamic process of controlling invasive species in a stochastic setting. We show how stochasticity, spatial location of infestation and control can influence the spread, control efficiency and optimal control strategies. The main aim of this paper is to analyse the relationship between economic parameters and stochastic spatial... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Spatial; Dynamics; Invasive; Economics; Stochastic; Optimisation; Environmental Economics and Policy. |
| Ano: 2011 |
URL: http://purl.umn.edu/103325 |
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| Bedene Szoke, Eva; Mohamed, Zsuzsanna. |
| Az általunk kidolgozott Biomassza Termelési Modell (BTM) lineáris programozáson alapul, és lehetővé teszi, hogy adott mezőgazdasági területre vonatkozóan meghatározzák az optimális vetésszerkezetet, különböző célfüggvények mellett. A különböző célfüggvények esetére vonatkozó optimalizálást a gazdasági környezet, különösen a szabályozó rendszer változása miatt tartottuk szükségesnek, amely adott körülmények között a legkedvezőbb gazdasági haszonnal jár. A döntés fő kérdése, hogy a rendelkezésre álló földterület és erőforrás-kapacitás mellett élelmiszercélú, vagy inkább energetikai célú hasznosítás irányában célszerű-e elmozdulni. --------------------------------------- We have developed a Biomass Production Model (BTM), which is based on linear programming.... |
| Tipo: Journal Article |
Palavras-chave: Biomassza-termelés; LP modell; Optimalizálás.; Biomass production; LP model; Optimisation; Land Economics/Use; Production Economics; Research Methods/ Statistical Methods. |
| Ano: 2010 |
URL: http://purl.umn.edu/99135 |
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| Nordblom, Thomas L.; Hume, Iain H.; Cresswell, Hamish; Glover, Mark; Hean, Robyn L.; Finlayson, John D.; Wang, Enli. |
| Although dryland farming and grazing have been practiced for over 130 years in the 17,000 ha Simmons Creek catchment without surface salinity problems, the area has been identified as a significant source of salt seepage to Billabong Creek in the NSW Murray catchment. Groundwater movement and salinity levels are spatially heterogenous at Simmons Creek. Groundwater of the upper catchment is relatively fresh and seemingly unconnected with the highly saline groundwater of the lower catchment. However, fresh surface water does flow from the upper to the lower catchment. This spatial diversity provokes the question of where high-water-use forest habitats might be placed to achieve different combinations of environmental services (greater water yield, lower... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Optimisation; Opportunity costs; Forest-habitat; Environmental services; Environmental Economics and Policy. |
| Ano: 2007 |
URL: http://purl.umn.edu/10357 |
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| Costa,Rejane Helena Ribeiro da; Medri,Waldir. |
| O modelo de produção adotado na suinocultura brasileira, principalmente na Região Oeste de Santa Catarina, é feita com os animais confinados em pequenas áreas, trazendo como conseqüência grande produção de dejetos. Este é diluído, através do uso de água para a limpeza das baias, aumentando seu volume. Seu lançamento nos cursos dágua da região está comprometendo a qualidade dos mananciais devido a contaminação bacteriológica e poluição por compostos químicos. Dessa forma, há necessidade de processos de tratamento para minimizar os problemas ambientais gerados por essa atividade. As lagoas de estabilização têm sido utilizadas, por apresentar um excelente desempenho quanto à eficiência de remoção da matéria orgânica, dos nutrientes e de coliformes fecais;... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Stabilisation ponds; Swine wastes; Costs; Models; Optimisation. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132002000300017 |
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| Priour, Daniel. |
| Trawls energy efficiency is greatly affected by the drag, as well as by the swept area regarding pelagic trawls and by the swept width for bottom ones. The drag results in an increase of the energy consumption and the sweeping influences the catch. In order to reduce the drag per swept area (or width) a numerical tool dedicated to the automatic optimisation of the trawl design has been developed. Based on a finite element method model for flexible netting structures, the tool modifies step by step a reference design. For each step the best-modified design, in terms of drag per swept area (or width), is kept. Such a methodology was used in two cases: which show a 43% increase in energy efficiency regarding the pelagic trawl case and 27% for the bottom trawl... |
| Tipo: Text |
Palavras-chave: Swept width; Swept area; Drag; Fuel consumption; Optimisation; Modelling; Trawl; Fishing gears. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6583.pdf |
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| Chalak, Morteza; Pannell, David J.. |
| Although there have been numerous studies on the economics of weed control, relatively few of these studies have focused on natural ecosystems. The aims of this papers are: A) to identify the combination of control options that is optimal for blackberry (Rubus anglocandicans) in Australian natural ecosystems, B) to assess whether an integrated control strategy is superior to chemical-only strategies, C) to evaluate the economic net benefits of specific biologically oriented control methods (a rust and grazing by goats), D) to determine how changes in model parameters affect the optimal control strategy. To address these aims, a stochastic dynamic simulation model and a stochastic dynamic programming model are developed. The results indicate that, while an... |
| Tipo: Presentation |
Palavras-chave: Environment; Economics; Weed; Stochastic; Optimisation; Management; Environmental Economics and Policy. |
| Ano: 2012 |
URL: http://purl.umn.edu/124373 |
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| Stott, Alistair W.. |
| Endemic disease of animals is an economic problem as it deprives humans of scarce resources that might otherwise satisfy human wants. Optimisation methods identify the strategies that minimise this economic problem. Given the potentially vast extent of the deprivation, not only in terms of lost wealth but also in terms of animal welfare, human health and environmental damage, this subject offers great benefits to decision-makers from the individual farm to the global level. This paper uses examples to illustrate the basic economic principles concerned. It shows how these principles may be extended to deal with current limitations in theory and practice. Lack of data is a common problem that may be dealt with by using computer simulation, theoretical... |
| Tipo: Working or Discussion Paper |
Palavras-chave: Economics; Decision analysis; Optimisation; Modelling; Endemic disease; Knowledge transfer; Health Economics and Policy. |
| Ano: 2006 |
URL: http://purl.umn.edu/46000 |
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| Priour, Daniel; Khaled, Ramez. |
| Trawls energy efficiency is greatly affected by the drag, as well as by the swept area. The drag results in an increase of the energy consumption and the sweeping influences the catch. Methods of optimisation of the trawl design have been developed in order to reduce the volume of carburant per kg of caught fish and consequently the drag per swept area of the trawl. Based on a finite element method model for flexible netting structures, the tool modifies step by step a reference design. For each step the best-modified design, in terms of drag per swept area is kept. Such optimisation can lead to a decrease of the drag or an increase of the swept area. In the second case, that could lead to an increase of fishing effort. To avoid such increase, which could... |
| Tipo: Text |
Palavras-chave: Fishing; Fuel; Fishing gear; Trawl; Optimisation; Fishing effort. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00170/28151/26381.pdf |
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| Hannesson, Rognvaldur; Kennedy, John O.S.. |
| Where a fish stock straddles or migrates between country A's exclusive economic zone (EEZ) and country B's EEZ, or the high seas, vesting ownership rights in the stock with A does not ensure efficient harvesting of the stock. This problem arises in the case of migratory tuna stocks in the Western and Central Pacific Ocean (WCPO). Four species of tuna reside for only part of the year in the EEZs of coastal states, many of which are Pacific Island Countries (PICs). Most of the harvesting of the stocks is carried out by distant water fishing nations such as the USA, Japan, Taiwan, China and Korea. Problems arise for achieving efficiency and equity in the harvesting of the stocks by disparate countries. The problems are made more difficult by changes in the... |
| Tipo: Conference Paper or Presentation |
Palavras-chave: Bioeconomic modelling; Game theory; Optimisation; Migratory tuna; Resource /Energy Economics and Policy. |
| Ano: 2007 |
URL: http://purl.umn.edu/9458 |
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| Registros recuperados: 22 | |
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