Moullec F.,Agrocampus Ouest |
Moullec F.,Montpellier University |
Gascuel D.,Agrocampus Ouest |
Bentorcha K.,Agrocampus Ouest |
And 2 more authors.
Journal of Marine Systems | Year: 2017
Trophic models are key tools to go beyond the single-species approaches used in stock assessments to adopt a more holistic view and implement the Ecosystem Approach to Fisheries Management (EAFM). This study aims to: (i) analyse the trophic functioning of the Celtic Sea and the Bay of Biscay, (ii) investigate ecosystem changes over the 1980–2013 period and, (iii) explore the response to management measures at the food web scale. Ecopath models were built for each ecosystem for years 1980 and 2013, and Ecosim models were fitted to time series data of biomass and catches. EcoTroph diagnosis showed that in both ecosystems, fishing pressure focuses on high trophic levels (TLs) and, to a lesser extent, on intermediate TLs. However, the interplay between local environmental conditions, species composition and ecosystem functioning could explain the different responses to fisheries management observed between these two contiguous ecosystems. Indeed, over the study period, the ecosystem's exploitation status has improved in the Bay of Biscay but not in the Celtic Sea. This improvement does not seem to be sufficient to achieve the objectives of an EAFM, as high trophic levels were still overexploited in 2013 and simulations conducted with Ecosim in the Bay of Biscay indicate that at current fishing effort the biomass will not be rebuilt by 2030. The ecosystem's response to a reduction in fishing mortality depends on which trophic levels receive protection. Reducing fishing mortality on pelagic fish, instead of on demersal fish, appears more efficient at maximising catch and total biomass and at conserving both top-predator and intermediate TLs. Such advice-oriented trophic models should be used on a regular basis to monitor the health status of marine food webs and analyse the trade-offs between multiple objectives in an ecosystem-based fisheries management context. © 2017 Elsevier B.V.
Ouammi A.,Unite Technologies |
Zejli D.,Unite Technologies |
Dagdougui H.,University of Genoa |
Benchrifa R.,Unite Technologies
Renewable and Sustainable Energy Reviews | Year: 2012
An artificial neural network (ANN) model is used to forecast the annual and monthly solar irradiation in Morocco. Solar irradiation data are taken from the new Satellite Application Facility on Climate Monitoring (CM-SAF)-PVGIS database. The database represents a total of 12 years of data from 1998 to 2010. In this paper, the data are inferred using an ANN algorithm to establish a forward/reverse correspondence between the longitude, latitude, elevation and solar irradiation. Specifically, for the ANN model, a three-layered, back-propagation standard ANN classifier is considered consisting of three layers: input, hidden and output layer. The learning set consists of the normalised longitude, latitude, elevation and the normalised mean annual and monthly solar irradiation of 41 Moroccan sites. The testing set consists of patterns just represented by the input component, while the output component is left unknown and its value results from the ANN algorithm for that specific input. The results are given in the form of the annual and monthly maps. They indicate that the method could be used by researchers or engineers to provide helpful information for decision makers in terms of sites selection, design and planning of new solar plants. © 2012 Elsevier Ltd. All rights reserved.
Dagdougui H.,University of Genoa |
Dagdougui H.,MINES ParisTech |
Minciardi R.,University of Genoa |
Ouammi A.,Unite Technologies |
And 2 more authors.
Energy Conversion and Management | Year: 2012
Renewable energy sources (RES) are an "indigenous" environmental option, economically competitive with conventional power generation where good wind and solar resources are available. Hybrid systems can help in improving the economic and environmental sustainability of renewable energy systems to fulfill the energy demand. The aim of this paper is to present a dynamic model able to integrate different RES and one storage device to feed a "Green" building for its thermal and electrical energy needs in a sustainable way. The system model is embedded in a dynamic decision model and is used to optimize a quite complex hybrid system connected to the grid which can exploit different renewable energy sources. A Model Predictive Control (MPC) is adopted to find the optimal solution. The optimization model has been applied to a case study where electric energy is also used to pump water for domestic use. Optimal results are reported for two main cases: the presence/absence of the energy storage system. © 2012 Elsevier Ltd. All rights reserved.
Brand B.,Wuppertal Institute for Climate |
Boudghene Stambouli A.,University of Science and Technology of Oran |
Zejli D.,Unite Technologies
Energy Policy | Year: 2012
This paper examines the effects of an increased integration of concentrated solar power (CSP) into the conventional electricity systems of Morocco and Algeria. A cost-minimizing linear optimization tool was used to calculate the best CSP plant configuration for Morocco's coal-dominated power system as well as for Algeria, where flexible gas-fired power plants prevail. The results demonstrate that in both North African countries, storage-based CSP plants offer significant economic advantages over non-storage, low-dispatchable CSP configurations. However, in a generalized renewable integration scenario, where CSP has to compete with other renewable generation technologies, like wind or photovoltaic (PV) power, it was found that the cost advantages of dispatchability only justify CSP investments when a relatively high renewable penetration is targeted in the electricity mix. © 2012 Elsevier Ltd.
Farr W.G.,University of Western Australia |
Creedon D.L.,University of Western Australia |
Goryachev M.,University of Western Australia |
Benmessai K.,Unite Technologies |
Tobar M.E.,University of Western Australia
Physical Review B - Condensed Matter and Materials Physics | Year: 2013
Progress in the emerging field of engineered quantum systems requires the development of devices that can act as quantum memories. The realization of such devices by doping solid-state cavities with paramagnetic ions imposes a tradeoff between ion concentration and cavity coherence time. Here, we investigate an alternative approach involving interactions between photons and naturally occurring impurity ions in ultrapure crystalline microwave cavities exhibiting exceptionally high quality factors. We implement a hybrid whispering gallery/electron spin resonance method to perform rigorous spectroscopy of an undoped single-crystal sapphire resonator over the frequency range 8-19 GHz, and at external applied DC magnetic fields up to 0.9 T. Measurements of high-purity sapphire cooled close to 100 mK reveal the presence of Fe3+, Cr3+, and V2+ impurities. A host of electron transitions are measured and identified, including the two-photon classically forbidden quadrupole transition (Δms=2) for Fe3+, as well as hyperfine transitions of V2+. © 2013 American Physical Society.
Fritzsche K.,Adelphi |
Zejli D.,Unite Technologies |
Energy Policy | Year: 2011
Global climate and energy governance have led to the creation of a wide range of international and regional institutions, initiatives and financial mechanisms dedicated to fostering renewable energies. Furthermore, a low-carbon economy has evolved in recent years. The objective of this paper is to assess the potential benefits and merits of these institutions, initiatives and mechanisms from the perspective of the Middle East and North Africa (MENA) region. The central questions are if and how these organizations, initiatives and finance mechanisms could support a country from MENA in its efforts to implement large-scale capacities for renewable energy production. For this purpose, Morocco was chosen as a case study. The findings in this paper indicate that the existing institutions and financial mechanisms do not sum up to a coordinated governance approach, although the main needs of a country or region appear to be addressed. The existing institutions and financial mechanisms vary significantly in their ability to support countries, especially those taking the lead in renewable energy implementation. © 2010 Elsevier Ltd.
Maiga A.I.,Unite Technologies
Journal of acquired immune deficiency syndromes (1999) | Year: 2012
Mutations in the connection domain (CD) of reverse transcriptase have been implicated in reverse transcriptase inhibitor (RTI) resistance, but this is controversial and little is known in non-B subtype HIV-1. We determined CD mutations prevalence in a population infected predominantly with CRF02_AG and investigated associations with phenotypic RTI resistance. Detected CD mutations were G335D (82.3%), A371V (69.8%), E399D (9.4%), N348I (5.2%), V365I (4.2), Y318F (2.1%), G333E (2.1%), and A360V (2.1%). Mutations were largely polymorphic and did not confer RTI resistance. The observed trend toward reduced likelihood of etravirine or nevirapine resistance in the presence of G335D should be investigated further.
Lebacq T.,Catholic University of Louvain |
Lebacq T.,Unite Technologies |
Baret P.V.,Catholic University of Louvain |
Stilmant D.,Unite Technologies
Agronomy for Sustainable Development | Year: 2013
Intensive livestock farming has raised issues about environmental impacts and food security during the past 20 years. As a consequence, there is a strong social demand for sustainable livestock systems. Sustainable livestock systems should indeed be environmentally friendly, economically viable for farmers, and socially acceptable, notably for animal welfare. For that goal, many sustainability indicators and methods have been developed at the farm level. The main challenge is using a transparent selection process to avoid assessment subjectivity. Here, we review typologies of sustainability indicators. We set guidelines for selecting indicators in a data-driven context, by reviewing selection criteria and discussing methodological issues. A case study is presented. The selected set of indicators mainly includes (1) environmental indicators focusing on farmer practices; (2) quantitative economic indicators; and (3) quantitative social indicators with a low degree of aggregation. The selection of indicators should consider (1) contextualization to determine purpose, scales, and stakeholders involved in the assessment; (2) the comparison of indicators based on various criteria, mainly data availability; and (3) the selection of a minimal, consistent, and sufficient set of indicators. Finally, we discuss the following issues: topics for which no indicators are measurable from available data should explicitly be mentioned in the results. A combination of means-based indicators could be used to assess a theme, but redundancy must be avoided. The unit used to express indicators influences the results and has therefore to be taken into account during interpretation. To compare farms from indicators, the influence of the structure on indicator values has to be carefully studied. © 2012 INRA and Springer-Verlag France.
Moubarik A.,Unite Technologies |
El-Belghiti K.,Unite Technologies |
Vorobiev E.,Unite Technologies
Food and Bioproducts Processing | Year: 2011
This work investigates the aqueous extraction from Fennel (Foeniculum vulgare) assisted by pulsed electric field (PEF), electrical discharges (ED) and ultrasound irradiations (UI). It aims the improvement of the solutes yield and the extraction kinetics at room temperature. Fennel gratings of size (1.5 × 0.75 × 30-50 mm3; width × height × length), were treated by PEF (intensity: 50-1200 V/cm and number of pulses: 50-1000), ED (voltage: 40 kV and number of discharges: 10-60) and ultrasound (intensity: 400 W/cm2 and treatment duration: 10-350 min). The liquid-to-solid (weight/weight) ratio equal to 2. All tests were carried out at room temperature (20 °C), under stirring at 250 rpm. The extraction kinetics was modelled using a simplified two-exponential kinetic model, which corresponds to mass transfer in two stages (rapid washing and slow diffusion). The optimal parameters of PEF, ED and UI, giving the maximal juice yield, were determined and the effect of these three treatments on the mass transfer rate was studied. © 2010 The Institution of Chemical Engineers.