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See detailCARACTÉRISATION DE LA DIVERSITÉ GÉNÉTIQUE DE CULTIVARS D’OIGNON (ALLIUM CEPA L.) DU NIGER EN VUE DE LEUR CONSERVATION IN SITU ET DE LEUR AMÉLIORATION
Abdou, Rabiou ULg

Doctoral thesis (2014)

Plante monocotylédone, allogame, entomophile, avec un cycle cultural annuel pour la production des bulbes, bisannuel pour celle des graines, l’oignon est l’un des légumes le plus important au Niger en ... [more ▼]

Plante monocotylédone, allogame, entomophile, avec un cycle cultural annuel pour la production des bulbes, bisannuel pour celle des graines, l’oignon est l’un des légumes le plus important au Niger en raison de son utilisation en alimentation et en médecine. Le semis en pépinière suivi d’un repiquage des planches est le mode de culture le plus fréquent chez les producteurs nigériens. Cette étude explore la diversité génétique des cultivars d’oignon du Niger. La diversité est à comprendre ici au sens de la diversité nommée, la diversité morphologique et la diversité moléculaire. Cette thèse se propose d’utiliser ces trois approches complémentaires pour identifier et caractériser les variétés et écotypes selon la perception des producteurs, de caractériser la diversité morphologique et agronomique à partir des descripteurs du genre Allium établis par Bioversity International, et d’analyser la diversité moléculaire des variétés et écotypes d’oignon du Niger à partir des marqueurs moléculaires microsatellites. Cinquante-deux écotypes nommés ont été inventoriés, mais après analyse et regroupement des synonymes, il ressort que dix-sept écotypes sont cultivés au Niger. Les principaux critères des paysans pour caractériser un écotype local sont la couleur des bulbes et la zone de provenance. Les variables quantitatives et qualitatives les plus distinctives entre les écotypes d’oignon sont la longueur et le diamètre des feuilles, le poids des bulbes, la couleur des feuilles, la forme et la couleur des bulbes, l’uniformité de la forme et de la couleur des bulbes. La distance génétique est plus grande, d’une part, entre les écotypes les plus éloignées géographiquement, et d’autre part, entre les écotypes les plus différents au niveau des caractères morphologiques. Le nombre de morphotypes varie de un à neuf par écotype testé. Les analyses moléculaires confirment la forte variabilité à l’intérieur des écotypes et les conclusions relatives à la distance génétique observée à partir des données morphologiques. A l’issue de ces travaux de caractérisation génétique de l’oignon, il est donc utile de combiner des stratégies de conservation in situ et ex situ, et l’exploitation de ces ressources génétiques pour améliorer la production et la rusticité des cultivars d’oignon du Niger. [less ▲]

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See detailMulti-period Stochastic Optimization Problems in Transportation Management
Pironet, Thierry ULg

Doctoral thesis (2014)

The topic of this thesis in management science is to propose a methodology to tackle multi-period decision problems including stochastic forecasts and to apply it to the field of transportation management ... [more ▼]

The topic of this thesis in management science is to propose a methodology to tackle multi-period decision problems including stochastic forecasts and to apply it to the field of transportation management. This methodology relies mostly on a sequence of numerical experimentations based on a set of algorithms to assess the value of the multi-period setting and the interest to use the stochastic information contained in the forecasts. Moreover, a statistical validation method to compare the performances of algorithms enables us to rank them meaningfully. From theory to practice, the thesis is structured into four parts. Firstly, we define the thesis subject and content. Then, based on a literature review, we present the past and present issues within the research field: "Optimization in Transportation". Mainly, we define the differences between multi-period stochastic models and classical deterministic mono-period ones. We explain how dynamism and stochasticity are taken into account within transportation problems. Secondly, our methodology, which is our main contribution, is exposed from a generic point of view in the theoretical research field: "Multi-period Stochastic Optimization Problems". On the one hand, temporal parameters and computational issues in multi-period optimization are detailed; on the other hand a summary of optimization techniques and algorithms for stochastic optimization problems is provided. Afterwards, the statistical validation of algorithmic performance is discussed. Then, part three contains two applications that lead us to set up the methodology, following an inductive method. The first problem, based on an industrial application at the start of the research, investigates a "multi-period vehicle loading problem with stochastic release dates". The second application, based on a more generic approach for the deployment of the methodology, deals with a "multi-period vehicle assignment problem with stochastic load availability". Finally, in the fourth part, we conclude on the thesis contributions and propose some perspectives. [less ▲]

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See detailThe PLATO 2.0 Mission
Rauer, H.; Catala, C.; Aerts, C. et al

in Experimental Astronomy (2014)

PLATO 2.0 has recently been selected for ESA’s M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental ... [more ▼]

PLATO 2.0 has recently been selected for ESA’s M3 launch opportunity (2022/24). Providing accurate key planet parameters (radius, mass, density and age) in statistical numbers, it addresses fundamental questions such as: How do planetary systems form and evolve? Are there other systems with planets like ours, including potentially habitable planets? The PLATO 2.0 instrument consists of 34 small aperture telescopes (32 with 25 s readout cadence and 2 with 2.5 s candence) providing a wide field-of-view (2232 deg 2) and a large photometric magnitude range (4–16 mag). It focusses on bright (4–11 mag) stars in wide fields to detect and characterize planets down to Earth-size by photometric transits, whose masses can then be determined by ground-based radial-velocity follow-up measurements. Asteroseismology will be performed for these bright stars to obtain highly accurate stellar parameters, including masses and ages. The combination of bright targets and asteroseismology results in high accuracy for the bulk planet parameters: 2 %, 4–10 % and 10 % for planet radii, masses and ages, respectively. The planned baseline observing strategy includes two long pointings (2–3 years) to detect and bulk characterize planets reaching into the habitable zone (HZ) of solar-like stars and an additional step-and-stare phase to cover in total about 50 % of the sky. PLATO 2.0 will observe up to 1,000,000 stars and detect and characterize hundreds of small planets, and thousands of planets in the Neptune to gas giant regime out to the HZ. It will therefore provide the first large-scale catalogue of bulk characterized planets with accurate radii, masses, mean densities and ages. This catalogue will include terrestrial planets at intermediate orbital distances, where surface temperatures are moderate. Coverage of this parameter range with statistical numbers of bulk characterized planets is unique to PLATO 2.0. The PLATO 2.0 catalogue allows us to e.g.: - complete our knowledge of planet diversity for low-mass objects, - correlate the planet mean density-orbital distance distribution with predictions from planet formation theories,- constrain the influence of planet migration and scattering on the architecture of multiple systems, and - specify how planet and system parameters change with host star characteristics, such as type, metallicity and age. The catalogue will allow us to study planets and planetary systems at different evolutionary phases. It will further provide a census for small, low-mass planets. This will serve to identify objects which retained their primordial hydrogen atmosphere and in general the typical characteristics of planets in such low-mass, low-density range. Planets detected by PLATO 2.0 will orbit bright stars and many of them will be targets for future atmosphere spectroscopy exploring their atmosphere. Furthermore, the mission has the potential to detect exomoons, planetary rings, binary and Trojan planets. The planetary science possible with PLATO 2.0 is complemented by its impact on stellar and galactic science via asteroseismology as well as light curves of all kinds of variable stars, together with observations of stellar clusters of different ages. This will allow us to improve stellar models and study stellar activity. A large number of well-known ages from red giant stars will probe the structure and evolution of our Galaxy. Asteroseismic ages of bright stars for different phases of stellar evolution allow calibrating stellar age-rotation relationships. Together with the results of ESA’s Gaia mission, the results of PLATO 2.0 will provide a huge legacy to planetary, stellar and galactic science. [less ▲]

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See detailLes effets délétères métaboliques et oxydants induits lors d'un sepsis sur la fonction rénale
Quoilin, Caroline ULg

Doctoral thesis (2014)

Acute kidney injury (AKI) is a frequent complication of sepsis that can increase mortality as high as 70%. The pathophysiology of this kidney failure was previously believed to be secondary to decreased ... [more ▼]

Acute kidney injury (AKI) is a frequent complication of sepsis that can increase mortality as high as 70%. The pathophysiology of this kidney failure was previously believed to be secondary to decreased global renal perfusion causing hypoxia-induced injury. However, new research suggests this paradigm is overly simplistic, and injury is now considered multifactorial in origin. Mechanisms that contribute to kidney injury mainly include inflammation, alterations in microvascular renal blood flow and changes in bioenergetics. To study the mechanism of oxygen regulation in acute kidney injury during sepsis, we developed a sepsis-induced in vitro model using proximal tubular epithelial cells (HK-2) exposed to a bacterial endotoxin (lipopolysaccharide, LPS). Our first investigation, by using both high-resolution respirometry and electron spin resonance spectroscopy, showed that HK-2 cells exhibit a decreased oxygen consumption rate when treated with LPS. Surprisingly, this cellular respiration alteration persists even after the stress factor is removed. We suggested that this irreversible decrease in renal oxygen consumption after LPS challenge is related to a pathologic metabolic down-regulation such as a lack of oxygen utilization by cells for ATP production. In the long term, this metabolic disturbance leads cells to a predominantly apoptotic death. To confirm this hypothesis of cytopathic hypoxia, we demonstrated that this alteration in the renal respiratory function is mainly due to an impairment in the metabolic activity of HK-2 cell mitochondria. Following LPS treatment, the oxidative phosphorylation is interrupted because of the inhibition of cytochrome c oxidase activity. As a consequence, disruptions in the electron transport and the proton pumping across the system occur, leading to a decrease of the mitochondrial membrane potential, the release of apoptotic-inducing factors and a decrease in ATP production. To clarify the mechanism by which the LPS induces mitochondrial alterations, we studied the oxidative stress generation in HK-2 cells. Interestingly, we revealed that the induction of a cytosolic oxidative stress is an event that appears before mitochondrial dysfunction in the LPS-treated HK-2 cells. This primary redox state is notably due to the activation of the two enzymes NADPH oxidase 4 and inducible NO synthase. The simultaneous production of anion superoxide and nitric oxide strongly suggests the formation of peroxynitrite, a relative stable powerful oxidant that can diffuse through mitochondrial compartments and undergo cytotoxic reactions. To our knowledge, our model reveals for the first time the role of NADPH oxidase-derived cytosolic ROS in triggering tubular cell damage. Moreover, after being first target of the oxidative stress, mitochondria become in turn producer of reactive oxygen species that carry on mitochondrial dysfunction. It seems thus that a mechanism of oxidative stress-induced redox cycling is a main cause of the mitochondrial dysfunction of LPS-treated HK-2 cells. The role of oxidants in mitochondrial dysfunction was further confirmed by the use of iNOS inhibitors or antioxidants that preserve cytochrome c oxidase activity and block mitochondrial membrane potential dissipation. Overall, these results suggest that sepsis-induced AKI should not only be regarded as failure of energy status but also as an integrated response, including transcriptional events, ROS signaling, mitochondrial activity and metabolic orientation such as apoptosis. [less ▲]

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See detailCost monitoring to promote the value added for clam raising farmers in the Northern area of Vietnam
Bui Thi, Nga; Tran Thu, Hoai; Tran Huu, Cuong et al

Conference (2014, September 02)

Clam farming in coastal provinces of Vietnam has notably developed since the last decade. It generated high income, improve socio-economic development for many local communities. However, many clam ... [more ▼]

Clam farming in coastal provinces of Vietnam has notably developed since the last decade. It generated high income, improve socio-economic development for many local communities. However, many clam raising farms are facing difficulties of farm management, disease control, markets and systems of quality control. This research aims to study about the real situation of cost monitoring in the clam raising farms in the Northern area of Vietnam and suggest some recommendation for apply a suitable model for cost monitoring to promote the value added for farmers. The paper based on the semi-structure, standard questionnaires and PRA method to collect data from 89 clam raising farms in two coastal provinces (Nam Dinh and Thai Binh) in the Northern area of Vietnam in 2014. The findings show that clam raising provides farmers a chance of getting high income parallel with high risk. There were 32.15% surveyed farms got profit, 32.14% of them met the breakeven and 35.71% was lost. The study finds out four key factors affecting farms’ economic performance and efficiency. The first is capacity of farm cost control as the cost for clam raising was very high at 8,142 to 9,190 USD per ha. The second is the farmers’ experience, skill, technique and ability of risk control. The third is low, unstable market price and unsuitable market channel with the dominant of the traders. Final factors is the area and location of clam raising. Despite of these difficulties, 55.14% surveyed farms still want to expand their production, 25% of them will continue, and only 17.86% will stop or change to other activities. In order to promote the value added for clam raising farmers, cost control should be paid more attention, improvement of the farmers’ capacity is necessary, and market should be regarded. [less ▲]

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See detailI know what you did last summer - High resolution mapping of wild boar damages with drones
Michez, Adrien ULg; Morelle, Kevin ULg; Lehaire, François ULg et al

Poster (2014, September 01)

Wild boar ability to cause important damages to agricultural lands is not anymore to be demonstrated. These damages often raise conflicts between farmers and hunters due to the associated economic losses ... [more ▼]

Wild boar ability to cause important damages to agricultural lands is not anymore to be demonstrated. These damages often raise conflicts between farmers and hunters due to the associated economic losses. Objective and accurate method for real impact assessment of losses suffered by farmers is thus needed. Currently,in Wallonia damage assessment is performed from the ground by experts, asked to evaluate precisely the area impacted. This task is time and man power consuming. Moreover, damaged areas are often large and consequently, sampling is mandatory and can induce accuracy issues. Recent development of unmanned aerial vehicle (UAV / drone) toghether with lower cost and better accessibility for civil society and scientific community, makes now possible the use of this technology for wildlife researches. Through photogrammetric 3D reconstruction of the field crop, UAV can allow to objectively and precisely measure the area impacted by wild boar damages. In a context of increasing issues caused by wild boar to agriculture, and the need for stakeholders for accurate impact assessment, we tested an innovative approach to estimate more effectively the area impacted by wild boar. [less ▲]

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See detailElastic damage to crack transition in a coupled non-local implicit discontinuous Galerkin/extrinsic cohesive law framework
Wu, Ling ULg; Becker, Gauthier ULg; Noels, Ludovic ULg

in Computer Methods in Applied Mechanics & Engineering (2014), 279

One current challenge related to computational fracture mechanics is the modeling of ductile fracture and in particular the damage to crack transition. On the one hand, continuum damage models, especially ... [more ▼]

One current challenge related to computational fracture mechanics is the modeling of ductile fracture and in particular the damage to crack transition. On the one hand, continuum damage models, especially in their non-local formulation which avoids the loss of solution uniqueness, can capture the material degradation process up to the localization of the damage, but are unable to represent a discontinuity in the structure. On the other hand cohesive zone methods can represent the process zone at the crack tip governing the crack propagation, but cannot account for the diffuse material damaging process. In this paper we propose to combine, in a small deformations setting, a non-local elastic damage model with a cohesive zone model. This combination is formulated within a discontinuous Galerkin nite element discretization. Indeed this DG weak formulation can easily be developed in a non-local implicit form and naturally embeds interface elements that can be used to integrate the traction separation law of the cohesive zone model. The method remains thus consistent and computationally e cient as compared to other cohesive element approaches. The effects of the damage to crack transition and of the mesh discretization are respectively studied on the compact tension specimen and on the double-notched specimen, demonstrating the efficiency and accuracy of the method. [less ▲]

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See detailPlanets and Stellar Activity: Hide and Seek in the CoRoT-7 system
Haywood, R. D.; Cameron, A. C.; Queloz, D. et al

in Monthly Notices of the Royal Astronomical Society (2014), 443(3), 2517-2531

Since the discovery of the transiting Super-Earth CoRoT-7b, several investigations have been made of the number and precise masses of planets present in the system, but they all yield different results ... [more ▼]

Since the discovery of the transiting Super-Earth CoRoT-7b, several investigations have been made of the number and precise masses of planets present in the system, but they all yield different results, owing to the star's high level of activity. Radial velocity (RV) variations induced by stellar activity therefore need to be modelled and removed to allow a reliable detection of all planets in the system. We re-observed CoRoT-7 in January 2012 with both HARPS and the CoRoT satellite, so that we now have the benefit of simultaneous RV and photometric data. We fitted the off-transit variations in the CoRoT lightcurve using a harmonic decomposition similar to that implemented in Queloz et al. (2009). This fit was then used to model the stellar RV contribution, according to the methods described by Aigrain et al. (2011). This model was incorporated into a Monte Carlo Markov Chain in order to make a precise determination of the orbits of CoRoT-7b and CoRoT-7c. We also assess the evidence for the presence of one or two additional planetary companions. [less ▲]

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See detailImmunovirologic Evaluation of Triomune (Lamivudine, Stavudine and Nevirapine) Antiretroviral Therapy in First Line HIV-1 Adult Patients in N’Djamena, Chad
Adawaye, Chatté Idekhim ULg

in Immunovirologic Evaluation of Triomune (Lamivudine, Stavudine and Nevirapine) Antiretroviral Therapy in First Line HIV-1 Adult Patients in N’Djamena, Chad (2014), 4

Dans cet article, nous avons évalué les taux des lymphocytes TCD4 et les charges virales chez des patients Vivant avec le VIH sous Triomune, à N'Djaména au Tchad. Cette évaluation a lieu au J0 avant le ... [more ▼]

Dans cet article, nous avons évalué les taux des lymphocytes TCD4 et les charges virales chez des patients Vivant avec le VIH sous Triomune, à N'Djaména au Tchad. Cette évaluation a lieu au J0 avant le traitement et après huit (8) mois de traitement. Nous avons remarqué que le taux d'échec à la Triomune était de 43,75% (21/48). [less ▲]

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See detailPredictive microbiology combined with metagenomic analysis targeted on the 16S rDNA : A new approach for food quality
Delhalle, Laurent ULg; Ellouze, Mariem; Taminiau, Bernard ULg et al

Poster (2014, September 01)

The food spoilage process is mainly caused by alteration micro-organisms and classical culture-based methods may not be relevant to understand the modifications of the microbial ecology in food products ... [more ▼]

The food spoilage process is mainly caused by alteration micro-organisms and classical culture-based methods may not be relevant to understand the modifications of the microbial ecology in food products. Metagenomic analysis targeted on 16S ribosomal DNA can elucidate microbial community structures at a muche higher resolution than was previously possible. Combined with predictive microbiological models, a new approach was investigated to take into account bacterial populations dynamics in perishable foods under different environmental conditions. White pudding samples, a typical Belgian pork meat product, were packed under food wrap (atmospheric air condition). Durability studies were conducted at 4°C, 12°C and a dynamic temperature profile according to the NF V01-003 standards (4°C (1/3 of the shelf life) - 8°C (2/3 of the shelf life)) during 15 days. The effect of organic acids was also investigated using a lactic acid (1.8% w/w) treatment. At each day of the trials, classical microbiological (total flora) and 16S rDNA metagenomic analysis were carried out on all these samples. For the metagenomic analysis, a sequencing library was generated, targeting the V1-V3 region of the 16S rDNA. The two major bacterial populations were thus identified (Psychrobacter sp and Brochotrix thermosphacta) and predictive microbiology models used to assess the growth parameters. Cardinal parameters for temperature were collected on the two main bacterial species. The model was validated using the data obtained at a dynamic temperature profile. The results of the simulations for Psychrobacter sp and Brochotrix thermosphacta show a good compliance between predicted and observed data. Compared to culture based methods on selective media and previous independent culture techniques, metagenomic analysis combined with predictive microbiology gives more valuable information, and could be considered as a technological breakthrough to control the quality or for accurately determining shelf life. [less ▲]

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See detailFraming and Political Discourse Analysis: Bush's Trip to Europe in 2005
Azpíroz Manero, María Luisa ULg

in Observatorio (OBS*) (2014), 8(3), 075-96

Framing empirical research analyzes the construction (frame building) and influence (frame effects) of the frames with which different social agents interpret and communicate reality. Based on Entman’s ... [more ▼]

Framing empirical research analyzes the construction (frame building) and influence (frame effects) of the frames with which different social agents interpret and communicate reality. Based on Entman’s (2004; 2008) and Kuypers’ (2008; 2009) contributions, this paper proposes and applies a qualitative methodology for the analysis of frame building in political discourse. It is located, therefore, on the strategic and methodological lines of framing research in political communication (Bartolomé; Rodríguez & Sádaba, 2012). As Kinder and Sanders state, frames are “invented and employed by political elites, often with an eye on advancing their own interests or ideologies, and intended to make favorable interpretations prevail” (Kinder & Sanders, 1990, p. 74). The paper includes a theoretical framework that reviews the evolution of framing literature in Communication, focusing especially on empirical studies. The contributions adopted for the elaboration of the methodology and the application process are explained in detail. The context of the case study, Bush’s discourse about the War on Terror on his trip to Europe in February 2005, is revised. Finally, the results obtained and the conclusions are detailed. [less ▲]

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See detailCalibration of Building Simulation Models: Assessment of Current Acceptance Criteria
Ruiz Flores, Roberto ULg; Lemort, Vincent ULg

in Proceedings of the 8th International Conference Improving Energy Efficiency in Commercial Buildings (IEECB’14) (2014, September)

In this paper, the most used acceptance criteria in calibration of building simulation models are introduced and tried out by means of a practical exercise. In order to simplify the process of obtaining ... [more ▼]

In this paper, the most used acceptance criteria in calibration of building simulation models are introduced and tried out by means of a practical exercise. In order to simplify the process of obtaining “simulated data” and to avoid carrying out a formal calibration procedure; two yearly testing profiles (hourly time scale) are created from real building electrical metered data (¼ hour profile). Both testing profiles represent two model responses that could possibly be obtained in a common calibration procedure. The objective of this work is to test the capabilities of the method to determine (1) the model adequacy to represent an existing situation; (2) the reliability of the model when predicting a future or different scenario and also (3) the ability of the method to orient the practitioner to upgrade the model when it provides a non-satisfactory response. To do this, the real accuracy of both testing profiles is verified by means of a complementary statistical bin analysis. This crosschecking analysis allows highlighting the strengths and weakness of the current criteria and determining whether they need to be revised, modified or complemented. At the end of the analysis, it is concluded that the capabilities of the current acceptance criteria are limited because don’t provide any satisfactory answer, indication or clue for none of the three points aforementioned and some other complementary tests (such as bin analysis) must be implemented and performed in order to properly declare a model as calibrated. [less ▲]

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See detailMeasurement uncertainty for persistent organic pollutants by isotope dilution mass spectrometry
Eppe, Gauthier ULg; Diletti, G; Fernandes, A et al

in Organohalogen Compounds (2014, September), 76

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See detailEmbargo russe sur les aliments européens : l'Europe doit montrer l'exemple
Habran, Maxime ULg

E-print/Working paper (2014)

Cette note a pour but d’apporter des éclaircissements sur les mesures en matière de politique agricole commune prises par l’Union européenne

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See detailComentário sobre o artigo de Pizzanelli
Jamoulle, Marc ULg

in Revista Brasileira de Medicina de Família e Comunidade (2014), 9(31),

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