Suchergebnisse

Colloque Dinabio mai 2008 à Montpellier. 3. Dynamiques de développement de l'AB ; International audience ; In Martinique, the environmental and food crisis, linked in particular to pollution by chlordecone, has led to a local demand for agro-ecological products. The aim of this study was to analyse: (i) institutional and organisational frameworks that determine the emergence and development conditions of these agricultural systems, and (ii) the technical and economical disincentives found on farms, in order to reveal the limiting factors and main levers. First and foremost, results showed that the "organic" sector is divided into two distinct groups of producers in terms of their certification process and of their integration into institutional systems. However, in both cases, an important disincentive is the absence of the control of indicators concerning the economic and financial assessment conditions of organic products. In addition, the technico–economic and agronomic analysis of farms revealed three major disincentives: (i) the absence of local references and technical support; (ii) weakness and dispersion in terms of supply and of access to specific inputs, and; (iii) low labour productivity. A coordinated effort involving local government agencies, producer organisations and technical and research institutions is necessary. ; Les résultats montrent tout d'abord que la filière de produits dits « biologiques » se structure en deux organisations de producteurs qui se différencient, tant par le mode de certification choisie que par leur niveaux d'insertion dans les dispositifs institutionnels conventionnels. Dans les deux cas néanmoins, un frein important est l'absence de maîtrise d'indicateurs sur les conditions d'évaluation économique et financière des produits biologiques. Par ailleurs, trois freins majeurs sont mis en évidence par l'analyse technico-économique et agronomique des exploitations (i) l'absence de référentiels et d'appui technique adaptés aux conditions locales, (ii) la faiblesse et la ...

Colloque Dinabio mai 2008 à Montpellier. 3. Dynamiques de développement de l'AB ; International audience ; In Martinique, the environmental and food crisis, linked in particular to pollution by chlordecone, has led to a local demand for agro-ecological products. The aim of this study was to analyse: (i) institutional and organisational frameworks that determine the emergence and development conditions of these agricultural systems, and (ii) the technical and economical disincentives found on farms, in order to reveal the limiting factors and main levers. First and foremost, results showed that the "organic" sector is divided into two distinct groups of producers in terms of their certification process and of their integration into institutional systems. However, in both cases, an important disincentive is the absence of the control of indicators concerning the economic and financial assessment conditions of organic products. In addition, the technico–economic and agronomic analysis of farms revealed three major disincentives: (i) the absence of local references and technical support; (ii) weakness and dispersion in terms of supply and of access to specific inputs, and; (iii) low labour productivity. A coordinated effort involving local government agencies, producer organisations and technical and research institutions is necessary. ; Les résultats montrent tout d'abord que la filière de produits dits « biologiques » se structure en deux organisations de producteurs qui se différencient, tant par le mode de certification choisie que par leur niveaux d'insertion dans les dispositifs institutionnels conventionnels. Dans les deux cas néanmoins, un frein important est l'absence de maîtrise d'indicateurs sur les conditions d'évaluation économique et financière des produits biologiques. Par ailleurs, trois freins majeurs sont mis en évidence par l'analyse technico-économique et agronomique des exploitations (i) l'absence de référentiels et d'appui technique adaptés aux conditions locales, (ii) la faiblesse et la dispersion concernant l'approvisionnement et l'accès aux intrants adaptés et enfin (iii) la faible productivité du travail. Une action collective de coordination impliquant les collectivités locales, les organisations de producteurs, les organismes techniques et la recherche est nécessaire.

International audience In Martinique, the environmental and food crisis, linked in particular to pollution by chlordecone, has led to a local demand for agro-ecological products. The aim of this study was to analyse: (i) institutional and organisational frameworks that determine the emergence and development conditions of these agricultural systems, and (ii) the technical and economical disincentives found on farms, in order to reveal the limiting factors and main levers. First and foremost, results showed that the "organic" sector is divided into two distinct groups of producers in terms of their certification process and of their integration into institutional systems. However, in both cases, an important disincentive is the absence of the control of indicators concerning the economic and financial assessment conditions of organic products. In addition, the technico–economic and agronomic analysis of farms revealed three major disincentives: (i) the absence of local references and technical support; (ii) weakness and dispersion in terms of supply and of access to specific inputs, and; (iii) low labour productivity. A coordinated effort involving local government agencies, producer organisations and technical and research institutions is necessary. ; Colloque Dinabio mai 2008 à Montpellier. 3. Dynamiques de développement de l'AB Les résultats montrent tout d'abord que la filière de produits dits « biologiques » se structure en deux organisations de producteurs qui se différencient, tant par le mode de certification choisie que par leur niveaux d'insertion dans les dispositifs institutionnels conventionnels. Dans les deux cas néanmoins, un frein important est l'absence de maîtrise d'indicateurs sur les conditions d'évaluation économique et financière des produits biologiques. Par ailleurs, trois freins majeurs sont mis en évidence par l'analyse technico-économique et agronomique des exploitations (i) l'absence de référentiels et d'appui technique adaptés aux conditions locales, (ii) la faiblesse et la dispersion ...

Every year about 45 000 forest fires occur in Europe, burning half a million hectares of forests and rural lands; between 1995 and 2004, more than 4 million hectares burned in the Mediterranean Region alone. Post-fire management of burned areas has been given much lesser attention than combating or preventing fires. However, important questions raise public concern and call for sound scientific knowledge to undertake appropriate post-fire actions: e.g., how to evaluate fire damages in economical terms? How to manage burned areas? Is it possible to establish, in the long-term, less flammable and more fire resilient forests and landscapes? To address these questions, a network of researchers and practitioners working in the field of fire ecology and forest management from all around Europe has been established in the frame of "COST Action FP0701-Post-Fire Forest Management in Southern Europe", supported by the European Union Research and Technology Development Framework Program. The Action aims to: i) develop and disseminate scientifically based decision criteria for planning post-fire forest management, from the stand to the landscape level; ii) translate this scientific knowledge into management practices; iii) connect scientists and stakeholders for exchanging experiences, evaluating these practices, and putting them into practice. To achieve these objectives the scientific groups involved will a) review and summarize the current scientific knowledge on post-fire management in Europe, by gathering and evaluating the results of previous and ongoing research; b) translate this knowledge into technical recommendations, by producing thematic reports, a book on the state-of-the-art of scientific knowledge on post fire assessment, and an electronic handbook on post-fire restoration; c) disseminate this knowledge to stakeholders, practitioners and decision makers. Besides publications and a project website already active (http://uaeco.biol.uoa.gr/cost/), training schools and one major conference will be organized. Although focused on Southern Europe, the outcomes of this Action will be crucial for central and northern European countries as well, as climate change and land use changes often leading to more homogeneous and expanding forest areas are already increasing fire hazard in those regions.

A study of the electronic conduction mechanisms and electrically active defects in polycrystalline Sb2Se3 is presented. It is shown that for temperatures above 200 K, the electrical transport is dominated by thermal emission of free holes, ionized from shallow acceptors, over the intergrain potential barriers. In this temperature range, the temperature dependence of the mobility of holes, limited by the intergrain potential barriers, is the main contributor to the observed thermal activation energy of the conductivity of 485 meV. However, at lower temperatures, nearest-neighbor and Mott variable range hopping transport in the bulk of the grains turn into the dominant conduction mechanisms. Important parameters of the electronic structure of the Sb2Se3 thin film such as the average intergrain potential barrier height ϕ = 391 meV, the intergrain trap density Nt = 3.4 × 1011 cm−2, the shallow acceptor ionization energy EA0 = 124 meV, the acceptor density NA = 1 × 1017 cm−3, the net donor density ND = 8.3 × 1016 cm−3, and the compensation ratio k = 0, 79 were determined from the analysis of these measurements. ; P. M. P. Salomé acknowledges the funding of Fundação para Ciencêa e Tecnologia (FCT) through the project IF/00133/ ̂2015. This research is supported by the Development of novel ultrathin solar cell architectures for low-light, low-cost, and flexible optoelectronic devices project (028075) co-funded by FCT and ERDF through COMPETE2020. B. Vermang has received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement no. 715027). A. Shongalova acknowledges the funding of Erasmus + program 2016/17. This work was funded by FEDER funds through the COMPETE 2020 Programme and by FCTPortuguese Foundation for Science and Technology under the projects UID/CTM/50025/2013. The financial support from Brazilian funding agencies CNPq, CAPES, and FAPEMIG is also acknowledged. ; info:eu-repo/semantics/publishedVersion

In this work, metal-insulator-semiconductor structures were fabricated in order to study different types of insulators, namely, aluminum oxide (Al2O3), silicon nitride, and silicon oxide (SiOx) to be used as passivation layers in Cu(In,Ga)Se-2 (CIGS) thin-film solar cells. The investigated stacks consisted of SLG/Mo/CIGS/insulator/Al. Raman scattering and photoluminescence measurements were done to verify the insulator deposition influence on the CIGS surface. In order to study the electrical properties of the CIGS-insulator interface, capacitance versus conductance and voltage (C-G-V) measurements were done to estimate the number and polarity of fixed insulator charges (Q(f)). The density of interface defects (D-it) was estimated from capacitance versus conductance and frequency (C-G-f) measurements. This study evidences that the deposition of the insulators at high temperatures (300 degrees C) and the use of a sputtering technique cause surface modification on the CIGS surface. We found that, by varying the SiOx deposition parameters, it is possible to have opposite charges inside the insulator, which would allow its use in different device architectures. The material with lower Dit values was Al2O3 when deposited by sputtering. ; This work was supported by European Union's Horizon 2020 research and innovation programme ARCIGS-M project under Grant 720887. The work of J. M. V. Cunha and P. M. P. Salome was supported by the Fundacao para a Ciencia e a Tecnologia (FCT) through the project IF/00133/2015. The work of J. P. Teixeira and J. P. Leitao was supported by the FCT through the project UID/CTM/50025/2013. The work of B. Vermang was supported by the European Research Council under the European Union's Horizon 2020 research and innovation programme under Grant 715027.

RiskBenefit4EU – Partnering to strengthen the risk–benefit assessment within EU using a holistic approach, is a recent European pilot project funded by EFSA and coordinated by Portugal (PT), integrating a multidisciplinary team from health and food institutes, national food safety authorities, R&D institutions and academia from PT, Denmark (DK) and France (FR). The main objectives of RiskBenefit4EU concerns the development of a set of Risk–Benefit Assessment (RBA) tools to assess and integrate food risks and benefits in the areas of microbiological, nutritional and chemical components through the development of a harmonised framework. This pilot project will validate the RBA framework created using a Portuguese case study on cereal-based foods. The research idea for food safety in risk assessment is to create an international network on RBA to promote and disseminate the outputs and knowledge acquired under RiskBenefir4EU, at European level. This network aims to promote knowledge and capacity building on RBA (acquired under RiskBenefit4EU) among European early stage researchers and to apply the harmonised framework on their countries. Health risks associated with consumption of cereal-based foods, an important source of nutrients with beneficial health effects, could increase soon due to climate changes in Europe (dry conditions and increased ambient temperatures could promote an increase in toxins production; occurrence of emergent compounds) so the dissemination and use of the RBA harmonized tools related with ingestion of cereal-based foods and derivatives could contribute to support future food and health policy in Europe. ; Projects GP/EFSA/AFSCO/2017/01-GA02 (EFSA), BioMAN/DAN/01 (INSA), UID/AMB/50017/2013 (CESAM) ; N/A

The incorporation of nanostructures in optoelectronic devices for enhancing their optical performance is widely studied. However, several problems related to the processing complexity and the low performance of the nanostructures have hindered such actions in real-life devices. Herein, a novel way of introducing gold nanoparticles in a solar cell structure is proposed in which the nanostructures are encapsulated with a dielectric layer, shielding them from high temperatures and harsh growth processing conditions of the remaining device. Through optical simulations, an enhancement of the effective optical path length of approximately four times the nominal thickness of the absorber layer is verified with the new architecture. Furthermore, the proposed concept in a Cu(In,Ga)Se2 solar cell device is demonstrated, where the short-circuit current density is increased by 17.4%. The novel structure presented in this work is achieved by combining a bottom-up chemical approach of depositing the nanostructures with a top-down photolithographic process, which allows for an electrical contact. ; This work was funded in part by the Fundação para a Ciência e a Tecnologia (FCT) under Grants IF/00133/2015, PD/BD/142780/2018 and SFRH/BD/ 146776/2019. The authors also want to acknowledge the European Union's Horizon 2020 Research and Innovation Programme through the ARCIGS-M project under Grant 720887, the Special Research Fund (BOF) of Hasselt University, the FCT through the project NovaCell (PTDC/CTM-CTM/28075/ 2017), and InovSolarCells (PTDC/FISMAC/29696/2017) co-funded by FCT and the ERDF through COMPETE2020. The authors also want to acknowledge Sandra Maya for the production of images used in this work. ; info:eu-repo/semantics/publishedVersion

In the past years, the strategies used to break the Cu(In,Ga)Se-2 (CIGS) light to power conversion efficiency world record value were based on improvements of the absorber optoelectronic and crystalline properties, mainly using complex post-deposition treatments. To reach even higher efficiency values, further advances in the solar cell architecture are needed, in particular, with respect to the CIGS interfaces. In this study, we evaluate the structural, morphological and optoelectronic impact of an Al2O3 layer as a potential front passivation layer on the CIGS properties, as well as an Al2O3 tunneling layer between CIGS and CdS. Morphological and structural analyses reveal that the use of Al2O3 alone is not detrimental to CIGS, although it does not resist to the CdS chemical bath deposition. The CIGS optoelectronic properties degrade when the CdS is deposited on top of Al2O3. Nonetheless, when Al2O3 is used alone, the optoelectronic measurements reveal a positive impact of this inclusion such as a very low concentration of interface defects while keeping the same CIGS recombination channels. Thus, we suggest that an Al2O3 front passivation layer can be successfully used with alternative buffer layers. Depth-resolved microscopic analysis of the CIGS interface with slow-muons strongly suggests for the first time that low-energy muon spin spectroscopy (LE-mu SR) is sensitive to both charge carrier separation and bulk recombination in complex semiconductors. The demonstration that Al2O3 has the potential to be used as a front passivation layer is of significant importance, considering that Al2O3 has been widely studied as rear interface passivation material. (C) 2020 Published by Elsevier Ltd. ; This work was supported in part by NovaCell (028075) and InovSolarCells (029696) and in part by FunrIa(do para a Ciencia c a Tecnologia and the ERDF through COMPETE2020. Fundacao para a Ciencia e a Tecnologia (FCT) is further acknowledged through 1F/00133/2015, PD/BD/142780/2018 and SFREHBD/1/1677G/2019. The European Union's Horizon 2020 research and innovation programme ARCIGS-M project (Grant agreement 720887) is also acknowledged. The financial support by National Funds through the FCT -Fundacao para a Ciencia e a Tecnologia, I.P., under the scope of the projects MB/50025/2020 and UIDP/50025/2020 -Programatico, are acknowledged. W. C. thanks the individual grant financed by the SusPhotoSolutions project CENTRO-01-0145-FEDER-000005. P. A. Fernandes would like to acknowledge FCT for the support of the project FCT UIDB/04730/2020. This work was supported with funds from FEDER (Programa Operacional Factores de Competitividade COMPETE) and from FCT [Fundacao para a Ciencia e Tecnologia (Portugal)] under Projects No. UID/FIS/04564/2016 and No. PTDC/FIS-MAC/29696/2017. The muon experiments were performed at the Swiss Muon Source SO, Paul Scherrer Institute, Villigen, Switzerland. The authors would like to thanks to Dr. Guy Brammertz for the helping in the interpretation of the TRPL data. ; Curado, MA (corresponding author), INL, Int Iberian Nanotechnol Lab, P-4715330 Braga, Portugal. marco.alberto@inl.int