691 research outputs found
Innovation and research in organic farming: A multiâlevel approach to facilitate cooperation among stakeholders
A wider range of stakeholders is expected to be involved in organic research. A decisionâsupport tool is needed to define priorities and to allocate tasks among institutions. Based on research and management experience in organic research, the authors have developed a framework for experimental and research
projects. The framework is based on a multiâlevel approach. Each level is defined according to the directness of the innovation impact on the organic systems. The projects carried out for each level were assessed over a ten-year period. Two applications are presented: analysis of crop protection strategies in horticulture and plant breeding programmes. When combined with four development models of organic farming, this multiâlevel analysis appears to be promising for defining research agendas
Steady state fluctuation relations for systems driven by an external random force
We experimentally study the fluctuations of the work done by an external
Gaussian random force on two different stochastic systems coupled to a thermal
bath: a colloidal particle in an optical trap and an atomic force microscopy
cantilever. We determine the corresponding probability density functions for
different random forcing amplitudes ranging from a small fraction to several
times the amplitude of the thermal noise. In both systems for sufficiently weak
forcing amplitudes the work fluctuations satisfy the usual steady state
fluctuation theorem. As the forcing amplitude drives the system far from
equilibrium, deviations of the fluctuation theorem increase monotonically. The
deviations can be recasted to a single master curve which only depends on the
kind of stochastic external force.Comment: 6 pages, submitted to EP
Assessing the benefits of Andean crop diversity on farmers' livelihood: insights from a development programme in Bolivia and Peru
This paper analyses the impact of a development programme designed at promoting the sustainable use of Andean Grain diversity. Results demonstrate that knowledge-sharing on agronomic practices, on benefits derived from consumption, and improving Andean Grain quality had a positive impact on income generation and farmer livelihoods. These results demonstrate the effectiveness of programmes aimed at improving rural livelihoods through greater knowledge transfer and use of local agrobiodiversity, wherein private benefits may incentivise the public benefits of agrobiodiversity use and conservation. Findings warrant the need to further monitor and evaluate the potential of agrobiodiversity to improve the well-being of rural communities
Integrability of one degree of freedom symplectic maps with polar singularities
In this paper, we treat symplectic difference equations with one degree of
freedom. For such cases, we resolve the relation between that the dynamics on
the two dimensional phase space is reduced to on one dimensional level sets by
a conserved quantity and that the dynamics is integrable, under some
assumptions. The process which we introduce is related to interval exchange
transformations.Comment: 10 pages, 2 figure
Enhancing agroecological innovations with a multi-level approach to experimental research needs
Public policies clearly aim at an ecologisation of agriculture. However, few concrete goals or incentives have been established to mobilize the experimental research. Applied to 13-year results of four experimental stations of the South-East of France, the Direct-Indirect-System multi-level analysis grid showed a diversification of their experimental strategies. These three levels of analysis, combined with the identification of different types of agroecosystems, appears as promising for instigating assessment and determining agroecological innovation priorities for an experimental station, a territory or a food chain
Agriculture numérique, une (r)évolution en marche dans les territoires ? Avant-propos
ForewordAvant-propo
Sensors for fruit firmness assessment: Comparision and fusion
Non-destructive measurement of fruit firmness is a difficult problem and many different sensors have been developed in order to achieve this task. Three different European laboratories were associated in collaborative experiments on peaches, to compare three different sensing techniques, namely, sound, impact and micro-deformation. A Bayesian classifier is associated with each individual sensor and provides a classification into three categories, namely âsoftâ, âhalf firmâ and âfirmâ. The fusion of the different sensors is performed by using Bayesian classifiers associated with heuristic methods for identity fusion. The result of the identity fusion is compared with the classification provided by an unsupervised algorithm based on destructive measurements. The fusion process provides some improvement in the classification results. For the individual sensors, the error rate of the classification varied from 19 to 28%, but the fusion process reduced this to 14%. Moreover, all measures of agreement between sensors lead to the conclusion that fusing sensors is better than using individual sensor
Agroecologia, movimento social, ciĂȘncia, prĂĄticas e polĂticas pĂșblicas: uma abordagem comparativa.
Resumo: Nos Ășltimos anos tanto no Brasil, como na França o tema da agroecologia tem ganhado forte visibilidade na sociedade e ocupado espaços importantes em programas e açÔes de desenvolvimento rural, bem como, no mundo da pesquisa cientĂfica, ensino e no movimento social. Diante desse fato, o objetivo do nosso artigo Ă© o de apresentar os primeiros resultados do projeto Capes-Cofecub 1. Primeiramente, analisaremos numa perspectiva cruzada ? da sociologia e das ciĂȘncias agrĂĄrias -, a evolução e a dinĂąmica da agroecologia, indicando as principais açÔes em curso tendo em conta o processo de institucionalização e estruturação crescente da agroecologia no Brasil e na França. Em seguida, proporemos uma reflexĂŁo em torno da agroecologia e Ă©tica. Abstract: In recent years, in Brazil as in France the theme of agroecology has gained high visibility in society and occupied important places in programs and rural development actions, as well as in the world of scientific research, education and social movement. Given this fact, the goal of our article is to present the first results of the project CAPES- COFECUB. First, from an interdisciplinary perspective cross- (sociology and the agronomic sciences), we analyze the evolution and dynamics of agroecology, indicating the main actions in the process of increasing institutionalization and structuring of agroecology in Brazil and France. Then, we propose a reflection on the perscpectiveconclude with the issue of agroecology and scientific ethics
Extreme events driven glassy behaviour in granular media
Motivated by recent experiments on the approach to jamming of a weakly forced
granular medium using an immersed torsion oscillator [Nature 413 (2001) 407],
we propose a simple model which relates the microscopic dynamics to macroscopic
rearrangements and accounts for the following experimental facts: (1) the
control parameter is the spatial amplitude of the perturbation and not its
reduced peak acceleration; (2) a Vogel-Fulcher-Tammann-like form for the
relaxation time. The model draws a parallel between macroscopic rearrangements
in the system and extreme events whose probability of occurrence (and thus the
typical relaxation time) is estimated using extreme-value statistics. The range
of validity of this description in terms of the control parameter is discussed
as well as the existence of other regimes.Comment: 7 pages, to appear in Europhys. Let
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