21,096 research outputs found
Modelling the Effect of Policy Reform on Structural Change in Irish Farming
End of project reportThe Mid Term Review (MTR) of the Common Agricultural Policy (CAP) has allowed for the decoupling of all direct payments from production from 2005 onwards; until then, most direct payments were coupled to production, requiring farmers to produce specific products in order to claim support. After decoupling, farmers will receive a payment regardless of production as long as their farm land is maintained in accordance with good agricultural practices. Direct payments to farmers have been an integral part of the CAP since the 1992 Mac Sharry reforms. Throughout the 1990s, market prices for farm produce have declined generally in line with policy while costs of production have continued to increase. Meanwhile, direct payments increased in value, increasing farmers’ reliance on this source of income. Furthermore, farmers adapted farming practices to maximise their receipt of direct payments, leading to the culture of ‘farming the subsidy’. By 1997, on cattle and tillage farms in Ireland 100 per cent of family farm income was derived from direct payments, meaning that on average the market-based revenue was insufficient to cover total costs
SLIM: A Language for Microcode Description and Simulation in VLSI
SLIM (Stanford Language for Implementing Microcode) is a programming language based system for
specifying and simulating microcode in a VLSI chip. The language is oriented towards PLA
implementations of microcoded machines using either a microprogram counter or a finite state
machine. The system supports simulation of the microcode and will drive a PLA layout program to
automatically create the PLA
Modelling Probabilistic Wireless Networks
We propose a process calculus to model high level wireless systems, where the
topology of a network is described by a digraph. The calculus enjoys features
which are proper of wireless networks, namely broadcast communication and
probabilistic behaviour. We first focus on the problem of composing wireless
networks, then we present a compositional theory based on a probabilistic
generalisation of the well known may-testing and must-testing pre- orders.
Also, we define an extensional semantics for our calculus, which will be used
to define both simulation and deadlock simulation preorders for wireless
networks. We prove that our simulation preorder is sound with respect to the
may-testing preorder; similarly, the deadlock simulation pre- order is sound
with respect to the must-testing preorder, for a large class of networks. We
also provide a counterexample showing that completeness of the simulation
preorder, with respect to the may testing one, does not hold. We conclude the
paper with an application of our theory to probabilistic routing protocols
GENEDEC
End of Project reportGENEDEC was a European project funded under the 6th Framework. It was co-ordinated by INRA Grignon with ten European partners and a time frame of 42 months. The purpose of the project was to conduct a quantitative and qualitative assessment of the socio-economic and environmental impacts of the decoupling of direct payments on agricultural production, markets and land use in the EU. It was envisaged that the pan-EU nature of the project would facilitate an international comparison of the effects of decoupling and would provide policy makers with sufficient information to identify the key winners and losers from decoupling throughout the EU. The project aimed to provide insights into the workability of decoupling and its impacts, and to analyse alternative policy options to improve the agricultural support system. Specifically, through the use of farm level models, this project estimated the effects of existing and proposed decoupled support schemes on production, land use and land prices and the implications for farm incomes and the future structural development of farms. The project was divided into 9 Work Packages depending on objectives and time frame of the project. The main role of RERC Teagasc was in Work Package 2 which aimed to develop farm level mathematical models and used the models developed to determine the impact of decoupling on Irish farms. The work in RERC started in November 2004 and ended in May 2006. A brief description of the models developed and results generated by RERC is provided here.GENEDEC was a European project funded under the 6th Framework
Feeding and the Equilibrium Feeder Animal Price-Weight Schedule
The feeder animal price is a derivative in the sense that its value depends upon the price of animals for the consumption market. It also depends upon the biological growth technology and feed costs. Daily maintenance costs are of particular interest to the husbander because they can be avoided through accelerated feeding. In this paper, the optimal feeding path under equilibrium feeder animal prices is established. This analysis is used to gain a better understanding of feeding decisions, regulation in feedstuff markets, and the consequences of genetic innovations. It is shown that days on feed can increase or decrease with a genetic innovation or other improvement in feed conversion efficiency. The structure of comparative prices for feeder animals at different weights, the early slaughter decision, and equilibrium in feeder animal markets are also developed. Feeder animal prices can increase over a weight interval if biological feed efficiency parameters are low over the interval.
Feeding and the Equilibrium Feeder Animal Price-Weight Schedule
Feeder animal prices depend on fed animal prices, the biological growth technology, and feed costs. In addition, daily maintenance costs can be avoided through accelerated feeding. These observations allow us to model optimal feeding under equilibrium feeder animal pricing. Our model enables a better understanding of regulation in feedstuff markets. The feeder animal price-weight schedule is likely decreasing and convex in weight. Prices for animals with better growth potential should be less sensitive to feed and fed animal prices. Prices for lighter animals should be more sensitive to these prices. Regression analyses on Southern Great Plains cattle prices provide support for this model.days on feed, energy use, feed ban, growth hormones, Kleiber's law, ration density, veal market, Livestock Production/Industries,
A multiple scales approach to evaporation induced Marangoni convection
This paper considers the stability of thin liquid layers of binary mixtures of a volatile (solvent) species and a non-volatile (polymer) species. Evaporation leads to a depletion of the solvent near the liquid surface. If surface tension increases for lower solvent concentrations, sufficiently strong compositional gradients can lead to Bénard-Marangoni-type convection that is similar to the kind which is observed in films that are heated from below. The onset of the instability is investigated by a linear stability analysis. Due to evaporation, the base state is time dependent, thus leading to a non-autonomous linearised system, which impedes the use of normal modes. However, the time scale for the solvent loss due to evaporation is typically long compared to the diffusive time scale, so a systematic multiple scales expansion can be sought for a finite dimensional approximation of the linearised problem. This is determined to leading and to next order. The corrections indicate that sufficient separation of the top eigenvalue from the remaining spectrum is required for the validity of the expansions, but not the magnitude of the eigenvalues themselves. The approximations are applied to analyse experiments by Bassou and Rharbi with polystyrene/toluene mixtures [Langmuir 2009 (25) 624–632]
INFORMATION ASYMMETRY AS A REASON FOR VERTICAL INTEGRATION
Vertical integration, information, product quality, Agribusiness,
On Monoculture and the Structure of Crop Rotations
An issue when seeking to identify rotation choice is persistence in yield-enhancement and input-saving carry-over effects. Focusing on carry-over length and the monoculture decision, we use quasi-convexity of choice functions to develop price-independent and price-dependent principles concerning rotation structure. Iowa corn-soybean rotation data suggest corn has one-year memory. For corn, soybeans in the prior year is yield increasing (16.5 bu./ac.) and nitrogen saving (51 lb./ac.). The hypothesis that soybean has two-year memory cannot be rejected. Corn in the prior year (two years) increases yield by 7 bu./ac. (11.6 bu./ac.). We simulate to find price and practice subsidy levels that support different rotations.
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