Consulta: creatorFacets:"van Ierland,   Ekko C."
Registros recuperados: 7
Data/hora: 13/06/2024 05:28:24

Estimating Feedback Effect in Technical Change: A Frontier Approach
Provedor de dados: 31
Autores: Otto,   Vincent M.; Kuosmanen,   Timo; van Ierland,   Ekko C.
This study examines whether today’s technical change depends on yesterday’s technical change. We propose to investigate this feedback effect by using the technical-change component of the Malmquist productivity index. This approach can overcome some problems in alternative patent-citation approaches. We apply the approach by estimating the feedback effect from production data of 25 OECD countries for 1980 through 1997. Our model yields evidence on a positive feedback effect with delays up till eight years. These findings are in line with patent-citation studies and bring us closer to a measure of the social returns to R&amp;D.
Tipo: Working or Discussion Paper
Palavras-chave: Research and Development/Tech Change/Emerging Technologies.
Ano: 2006
URL: http://purl.umn.edu/12086

The Effect of HIV/AIDS Driven Labor Organization on Agrobiodiversity: an Empirical Study in Ethiopia
Provedor de dados: 31
Autores: Gebreselassie,   Kidist; Wesseler,   Justus; van Ierland,   Ekko C.
Improved micronutrient intake contributes to delaying the progression of HIV into AIDS and to reducing HIV infection rates. Higher agrobiodiversity in the homegarden contributes to improving the nutritional status of farm households. Farm households with HIV/AIDS affected members observe a decrease in labor supply and productivity causing them to reallocate labor. The reallocation of labor may result in change in agrobiodiversity. Sharecropping is often used to alleviate labor shortage in agricultural production. The purpose of this paper is to analyze the implications of HIV/AIDS on agrobiodiversity through sharecropping arrangements. The study is based on a survey among 205 farm households in the Jimma zone of South Western Ethiopia. Results show that...
Tipo: Conference Paper or Presentation
Palavras-chave: Agrobiodiversity; Ethiopia; HIV/AIDS; Labor organization; Sharecropping; Farm Management; Labor and Human Capital.
Ano: 2007
URL: http://purl.umn.edu/7929

Biological control of invasive plant species: stochastic economic analysis
Provedor de dados: 31
Autores: Chalak-Haghighi,   Morteza; Ruijs,   Arjan; van Ierland,   Ekko C.
We analysed to what extent the stochastic effects of two biological control agents (i.e. weevils and mycoherbicides) affect the optimal choice of Californian thistle control. A stochastic, dynamic optimisation model was set up to analyse strategies that maximise the expected net present values. We analysed the cost-effective strategies to control the thistle for deterministic and stochastic cases. Results show that the stochasticity of the efficacy of weevils does not affect the optimal strategy. Compared to the deterministic case, however, mycoherbicides will be introduced at a higher level of weed density if we take the stochastic effect of mycoherbicides into account.
Tipo: Conference Paper or Presentation
Palavras-chave: Stochastic; Optimisation; Biological control; Californian thistle; Economics.
Ano: 2009
URL: http://purl.umn.edu/48153

Economics of controlling invasive species: optimal control and stability of ecological-economic system
Provedor de dados: 31
Autores: Chalak,   Morteza; Ruijs,   Arjan; Hemerik,   Lia; van der Werf,   Wopke; van Ierland,   Ekko C.
Natural enemies such as herbivores that are introduced to reduce invasive plants can spill over into nature, threaten indigenous species and impose significant costs. We develop a bioeconomic model to analyse the optimal control management strategy of an introduced herbivore that has spilled over from a managed system to a natural area. Cost-effective control strategies are analysed that reduce the spillover effects of herbivores on endangered plants species to reduce the risk of extinction and increase benefits obtained from the ecosystem. We consider two competing indigenous plant species as the representatives of the plant community. Only one of these species is consumed by introduced herbivore. We show that the optimal level of controlling herbivores...
Tipo: Presentation
Palavras-chave: Economics; Biological agent; Externality; Spillover; Control; Environmental Economics and Policy.
Ano: 2012
URL: http://purl.umn.edu/124374

DYNAMICS OF AGRICULTURAL GROUNDWATER EXTRACTION
Provedor de dados: 31
Autores: Hellegers,   Petra J.G.J.; Zilberman,   David; van Ierland,   Ekko C.
Agricultural shallow groundwater extraction can result in desiccation of neighbouring nature reserves and degradation of groundwater quality in the Netherlands, whereas both externalities are often not considered when agricultural groundwater extraction patterns are being determined. A model is developed to study socially optimal agricultural shallow groundwater extraction patterns. It shows the importance of stock size to slow down changes in groundwater quality.
Tipo: Conference Paper or Presentation
Palavras-chave: Resource /Energy Economics and Policy.
Ano: 2001
URL: http://purl.umn.edu/20446

Economic Incentives for Entry and Exit in Gum Arabic Agroforestry System in Sudan
Provedor de dados: 31
Autores: Rahim,   Afaf H.; van Ierland,   Ekko C.; Wesseler,   Justus.
The gum tree (Acacia senegal) in the Sahel-Sudan zone has many environmental benign functions. An important function is to control desertification. In this paper we analyze farmers' economic incentives to preserve the existing gum trees and their incentives to create new plantations using a real options approach. Results indicate that agricultural crops provide higher economic benefits as compared to gum agroforestry system. However, on the one hand, as gum arabic is produced during the dry period and land is abundant, there are low incentives for deforestation. Instead, farmers' tend to leave the land idle and let the tree growing. On the other hand, our results suggest that an increase in the prices of gum arabic of about 330 per cent is needed to induce...
Tipo: Conference Paper or Presentation
Palavras-chave: Gum arabic; Deforestation; Entry and exit; Real options; Sudan; Crop Production/Industries; D4; N5; O13; Q12; Q23.
Ano: 2006
URL: http://purl.umn.edu/25720

Designing a Decision Support System for Marine Reserves Management: An Economic Analysis for the Dutch North Sea
Provedor de dados: 31
Autores: van Ierland,   Ekko C.; Ding,   Hongyu; Ruijs,   Arjan.
In this paper we discuss how a Decision Support System (DSS) for managing the marine environment can be set up. We use the Driving force-Pressure-State-Impact-Respond (DPSIR) framework to analyze which are the major driving forces impacting upon the marine environment in the North Sea. Moreover, a number of potential responses are identified. Furthermore, a preliminary and simplified optimization model has been set up and can be used in a DSS to decide on the best location of marine reserves for the protection of species. The model is based on a bio-economic metapopulation model that can be used to decide which parts of the sea should be opened for fisheries and which should be protected as marine reserve. It accounts for the dispersal of fish and...
Tipo: Working or Discussion Paper
Palavras-chave: Resource /Energy Economics and Policy.
Ano: 2007
URL: http://purl.umn.edu/10266