Last 7 days     Results 641-660 of 23122.   28 29 30 31 32 33 34 35 36 37 38   Transit confirmation and improved stellar and planet parameters for the super-Earth HD 97658 b and its host starVan Grootel, Valérie ; Gillon, Michaël ; Valencia, D. et alin Astrophysical Journal (2014), 786Super-Earths transiting nearby bright stars are key objects that simultaneously allow for accurate measurements of both their mass and radius, providing essential constraints on their internal composition ... [more ▼]Super-Earths transiting nearby bright stars are key objects that simultaneously allow for accurate measurements of both their mass and radius, providing essential constraints on their internal composition. We present here the confirmation, based on Spitzer transit observations, that the super-Earth HD 97658 b transits its host star. HD 97658 is a low-mass ($M_*=0.77\pm0.05\,M_{\odot}$) K1 dwarf, as determined from the Hipparcos parallax and stellar evolution modeling. To constrain the planet parameters, we carry out Bayesian global analyses of Keck-HIRES radial velocities, and MOST and Spitzer photometry. HD 97658 b is a massive ($M_P=7.55^{+0.83}_{-0.79} M_{\oplus}$) and large ($R_{P} = 2.247^{+0.098}_{-0.095} R_{\oplus}$ at 4.5 $\mu$m) super-Earth. We investigate the possible internal compositions for HD 97658 b. Our results indicate a large rocky component, by at least 60% by mass, and very little H-He components, at most 2% by mass. We also discuss how future asteroseismic observations can improve the knowledge of the HD 97658 system, in particular by constraining its age. Orbiting a bright host star, HD 97658 b will be a key target for coming space missions TESS, CHEOPS, PLATO, and also JWST, to characterize thoroughly its structure and atmosphere. [less ▲]Detailed reference viewed: 12 (4 ULg) Entre recettes du Soi et recettes de l'Autre. Ethnographie de pratiques culinaires marocaines à Sesto San Giovanni (Milan, Italie)Mescoli, Elsa Doctoral thesis (2014)La thèse porte sur les processus de subjectivation d’un groupe de femmes marocaines résidant dans la ville de Sesto San Giovanni, dans le nord de l’Italie. Elsa Mescoli considère les habitudes ... [more ▼]La thèse porte sur les processus de subjectivation d’un groupe de femmes marocaines résidant dans la ville de Sesto San Giovanni, dans le nord de l’Italie. Elsa Mescoli considère les habitudes alimentaires et les pratiques culinaires de ces femmes et de leurs familles, facteurs qui agissent dans la construction de soi à plusieurs niveau : celui intime, en contexte domestique ; celui partagé/contesté, en contexte publique. L’étude se situe au croisement entre l’anthropologie de l’alimentation, l’anthropologie de la culture matérielle et l’anthropologie des migrations. En fait, ces processus sont analysés en adoptant une perspective praxéologique, c’est-à-dire en portant l’attention sur la matérialité. La thèse met en évidence les « ingrédients » concrets de la définition de soi des femmes considérées, ainsi que de leurs rapports interpersonnels et « interculturels ». [less ▲]Detailed reference viewed: 11 (2 ULg) LARGE-SCALE SYNTHESIS OF CARBON NANOTUBES: A GREAT CHALLENGE BETWEEN PRODUCTIVITY AND PRODUCTIONPirard, Sophie ; Douven, Sigrid ; Pirard, Jean-Paul Conference (2014, April 29)Detailed reference viewed: 4 (4 ULg) Multiscale modelling of angiogenesis during normal and impaired bone regenerationCarlier, Aurélie Doctoral thesis (2014)Bone regeneration is, like many other healing events, a complex, well-orchestrated process involving a myriad of different cell types and regulated by countless biochemical, physical and mechanical ... [more ▼]Bone regeneration is, like many other healing events, a complex, well-orchestrated process involving a myriad of different cell types and regulated by countless biochemical, physical and mechanical factors. But unlike other adult biological tissues, the majority of bone fractures can heal without the production of scar tissue, eventually recovering the original bone shape, size and strength. Despite bone’s remarkable healing capacity and the continuing research efforts, the impaired healing of complex orthopaedic cases is still not fully understood. This PhD work hypothesises that computational modelling can make a substantial contribution to the bone regeneration field by proposing and testing the underlying mechanisms of action as well as by designing and optimising experimental strategies in silico. In the first part of this work, an existing bioregulatory model of fracture healing is extended with an intracellular module of Dll4-Notch1 signalling in order to capture the ingrowth of new blood vessels through sprouting angiogenesis. The predictions of the new MOSAIC model are compared to experimental results and an extensive sensitivity analysis is performed on the newly introduced parameters. The potential of the MOSAIC model to investigate the influence of the molecular mechanisms on angiogenesis and consequently the bone formation process is illustrated. In the second part of this work, the MOSAIC model is further improved with a rigorous implementation of the influence of oxygen on the behaviour of skeletal cells. A comprehensive literature study is performed in order to ensure the correspondence of the oxygen ranges of the cell-specific oxygen-dependent processes with the state-of-the-art experimental knowledge. The oxygen model is corroborated with previously published experimental results. The robustness of the oxygen model with respect to the newly introduced oxygen thresholds is demonstrated by a sensitivity analysis. Some limitations and shortcomings of the oxygen model are identified together with suggestions for future work. In the last part of this work, the added value of the oxygen model is shown by applying it to three cases of impaired bone healing: the occurrence of nonunions in critical size defects, bone graft healing in a compromised environment and the impaired healing of bone fractures in NF1 patients. Not only is the oxygen model used to determine the underlying mechanisms of action, potential treatment strategies for the respective challenging orthopaedic conditions are also designed and optimised in silico. In conclusion, this PhD thesis demonstrates the potential of an integrative in vivo-in silico approach to advance our current understanding of bone regeneration as well as to design effective treatments of complex bone fractures. [less ▲]Detailed reference viewed: 9 (0 ULg) CONTRIBUTION A L’ETUDE DE L’IMMUNOPATHOGENIE DE L’ASPERGILLOSE NASO-SINUSALE ET DE LA RHINITE LYMPHOPLASMOCYTAIRE CHEZ LE CHIENMercier, Elise Doctoral thesis (2014)Detailed reference viewed: 27 (4 ULg) Control of attosecond electronic dynamics in moleculesMignolet, Benoît Doctoral thesis (2014)Detailed reference viewed: 7 (2 ULg) Dioxin Analyses. The Dogs Bark, but the Caravan Goes on...Focant, Jean-François Scientific conference (2014, April 28)Detailed reference viewed: 11 (0 ULg) Microfossils’ diversity from the Proterozoic Taoudeni Basin, MauritaniaBeghin, Jérémie ; Javaux, Emmanuelle ; Houzay, Jean-Pierre et alin European Geosciences Union General Assembly 2014 Vienna, Austria, 27 April – 02 May 2014 (abstract book) (2014, April 27)Detailed reference viewed: 6 (0 ULg) Introduction aux travaux de Luciano Del Pistoia : corps et psychoseEnglebert, Jérôme Scientific conference (2014, April 25)Detailed reference viewed: 11 (1 ULg) Nanostructured catalysts by sol-gel processLambert, Stéphanie ; Heinrichs, Benoît Conference (2014, April 25)Detailed reference viewed: 29 (4 ULg) Predicting Grain Protein Content of Winter WheatMansouri, Majdi ; Dumont, Benjamin ; Destain, Marie-France in ESANN 2014 Proceedings (2014, April 24)Detailed reference viewed: 10 (1 ULg) A Frequency-domain Approach to Subspace Identification of Nonlinear Systems, Application to Aerospace StructuresNoël, Jean-Philippe Doctoral thesis (2014)The construction of mathematical models from experimental data is an essential step in the design process of engineering systems. The different tasks involved in this activity, from the measurement and ... [more ▼]The construction of mathematical models from experimental data is an essential step in the design process of engineering systems. The different tasks involved in this activity, from the measurement and processing of data to the validation of the model, fall into the general field of system identification. In structural dynamics, the theoretical and experimental aspects of linear system identification have been successfully addressed since the early seventies, and mature analytical, computational and testing tools have emerged. Nonlinear system identification of vibrating structures has also enjoyed significant advances during the past few years. However, the common practice in industry is to ignore nonlinearities, arguably because their analysis is still regarded as impractical. The objective of this doctoral thesis is precisely to progress towards the development of a practical system identification methodology dedicated to real-life nonlinear structures. The first facet of the thesis is to introduce a nonlinear generalisation in the frequency domain of the so-called subspace identification methods. The proposed frequency-domain nonlinear subspace identification (FNSI) approach yields accurate models of large-scale systems comprising strong nonlinearities, closely-spaced modes and high damping. Because it can also estimate a large number of parameters while maintaining an acceptable computational burden, the second facet of this research is to investigate the utilisation of cubic splines as a very flexible means to model complex nonlinearities. Finally, the third facet of the present work is to derive nonlinear models with optimal statistical properties in the presence of measurement noise. This is achieved by embedding the FNSI method into the maximum likelihood identification framework. The scope of the identification and modelling tools developed in this thesis encompasses nonlinear structural systems originating from the various areas of vibration engineering, including the aerospace, mechanical or civil fields, amongst others. Throughout the dissertation, these tools are illustrated using numerical and experimental structures of increasing complexity, mainly related to aerospace applications. [less ▲]Detailed reference viewed: 38 (14 ULg) Machine learning techniques to assess the performance of a gait analysis systemPierard, Sébastien ; Phan-Ba, Rémy; Van Droogenbroeck, Marc Poster (2014, April 24)This paper presents a methodology based on machine learning techniques to assess the performance of a system measuring the trajectories of the lower limbs extremities for the follow-up of patients with ... [more ▼]This paper presents a methodology based on machine learning techniques to assess the performance of a system measuring the trajectories of the lower limbs extremities for the follow-up of patients with multiple sclerosis. We show how we have established, with the help of machine learning, four important properties about this system: (1) an automated analysis of gait characteristics provides an improved analysis with respect to that of a human expert, (2) after learning, the gait characteristics provided by this system are valuable compared to measures taken by stopwatches, as used in the standardized tests, (3) the motion of the lower limbs extremities contains a lot of useful information about the gait, even if it is only a small part of the body motion, (4) a measurement system combined with a machine learning tool is sensitive to intra-subject modifications of the walking pattern. [less ▲]Detailed reference viewed: 22 (2 ULg) Le rôle du commerce frontalier des produits alimentaires avec le Rwanda dans l'approvisionnement des ménages de la ville de Bukavu (Province du Sud-Kivu)Vwima Ngezirabona, Stany Doctoral thesis (2014)This thesis aims at highlighting the importance of food supply from the Rusizi District (Rwanda) in the food security of the city Bukavu (Democratic Republic of Congo). Due to the informal nature of this ... [more ▼]This thesis aims at highlighting the importance of food supply from the Rusizi District (Rwanda) in the food security of the city Bukavu (Democratic Republic of Congo). Due to the informal nature of this supply, it was necessary to characterize its magnitude, drivers, and consequences as well as to develop policies that are likely to improve this supply and facilitate regional integration. The fieldwork consisted of two series of investigations. The first series of data collection included scoring the flow of food supply from Rusizi District during three months and for each of the food supply axes of Bukavu city. Secondly, a questionnaire was administered to a sample of 233 households, wherein 76 consuming households and 157 reselling households. Results from the scoring exercise show that 2,021 households on average cross both borders (Rusizi 1 and Ruzizi 2) for their food supply daily. A total of 661 of these households (about 32.7%) are direct food consumers and 1,360 households (about 67.3%) are food resellers. Excepted for cassava (which is a traditional staple of South Kivu), plantains (because of conservation problem, much more coming from within the province), and beans (much more from North Kivu), other major food products are imported from Ruzizi district in Rwanda. In this regard, the dependency ratios towards Rwanda remain much higher for products such as maize (66%), potatoes (82%), sorghum (73%), groundnut (69%), sweet potato (98%), rice (70%), and beef and pork meat (85%). With such dependency ratios, Bukavu is a major food market of the Rusizi District (Rwanda) food products. This is however far from being confirmed by official import statistics of the Congolese Control Office (CC0) which, except for rice, underestimates the border trade for a large portion of food commodities flows. The commodities analyzed provide the population of the city of Bukavu 1027 kcal per person per day from which 593.5 kcal, 338.9 kcal and 92.4 kcal are provided by products respectively from Rwanda, North-Kivu and South-Kivu. The calories consumed in the city of Bukavu are mainly of vegetable origin dominated by maize (563.1 kcal), cassava (120 kcal) and beans (167.1 kcal), which play a strategic role given their importance in the food habits of Bukavu. The significant flows of food supplies from Rusizi district are a major contribution to the livelihood of thousands of families in the city of Bukavu. It emerges that all products supplied from Rusizi district by reselling households generate positive return per month demonstrating a positive remuneration not only for the invested capital, but also for the time and effort invested in the activity (average 5.67 hours). More than 68 % of reselling households claim are satisfied with the result of this activity and allocate the generated income mainly to cover subsistence needs. In this sense, the economic impact of border trade on incomes of reselling households is a reality. The analysis of budgets of consuming households shows that 69.1% of food expenditure and 48.8% of total expenditure of consuming households cross the border. The significant impact of food supplies from the Rusizi district on reducing households’ income poverty, reflects the interests of border trade which only reinforces the structural and relative decline of the agricultural sector in South Kivu already confronted to various problems. The free trade policy advocated by a large number of sub-regional and regional communities such as CEPGL and COMESA will make the Rusizi originating food supply of Bukavu more efficient, but it remains a short-term solution of food security of the city and the province in general. In the long term, it would be better to stimulate the production and promote local food trade. To achieve this, investments need to be channeled to the agricultural sector. It is at this price that the agricultural sector in South-Kivu can be revived and reach the threshold of self-sufficiency, and even create a surplus for export. Admittedly, this solution then poses the problem of reconversion of consuming households and sellers-households that we should rethink from the outset. [less ▲]Detailed reference viewed: 9 (4 ULg) Le psychopathe : apprésentation, chosification de l’alter ego et compétences émotionnellesEnglebert, Jérôme Conference (2014, April 23)La psychopathie est une entité diagnostique « trouble », tant au sein de la tradition psychopathologique que dans les nosographies internationales contemporaines (DSM-IV et DSM-V). Le modèle faisant ... [more ▼]La psychopathie est une entité diagnostique « trouble », tant au sein de la tradition psychopathologique que dans les nosographies internationales contemporaines (DSM-IV et DSM-V). Le modèle faisant autorité en psychologie forensic est celui développé par R.D. Hare (2003) à travers une échelle diagnostique appelée PCL-R. Ce modèle rencontre, d’un point de vue théorique, plusieurs apories, et, d’un point de vue clinique, de nombreuses impasses. Nous proposons de réaliser un exercice de compréhension psychopathologique axé sur notre pratique clinique en nous inspirant des recommandations du courant de la psychopathologie phénoménologique (Minkowski, 1966 ; Binswanger, 1960 ; Stanghellini, 2006 ; Sass, Parnas & Zahavi, 2011). Celui-ci suggère de procéder par la mise en évidence de la structure psychopathologique qui organise le fonctionnement psychologique du sujet. De façon plus précise, nous centrerons notre propos sur deux dimensions essentielles à l’être-au-monde psychopathique. D’une part, nous réaliserons une comparaison avec l’être-au-monde maniaque à travers les variables de l’apprésentation et de la chosification de l’alter ego – telles que les développe Binswanger (1960). Nous discuterons, d’autre part, du vécu émotionnel propre à la psychopathie qui est davantage source d’adaptation (du moins en certaines situations) que de carence véritable. Ce constat nous permettra de rediscuter brièvement de la notion d’empathie en psychopathologie. Nous verrons que ces dimensions propres à l’existence psychopathique font apparaitre une thématique explicitement absente de la nosographie de Hare, celle de la morale. [less ▲]Detailed reference viewed: 31 (1 ULg) L’archéologie du volontaire : la dimension imaginaire de l’agir selon Paul RicœurZincq, Aurélien Conference (2014, April 22)Detailed reference viewed: 19 (2 ULg) David Knoke, Economic networksDufays, Frédéric in Lectures (2014)Detailed reference viewed: 7 (0 ULg) Incertitudes liées à la modélisation agro-environnementale en vue de développer des outils d'aide à la décisionDumont, Benjamin Doctoral thesis (2014)The European Nitrates Directive 91/6/76/EEC aims to ensure water quality by preventing pollution of surface and groundwater induced by nitrates originating from agricultural sources and by promoting ... [more ▼]The European Nitrates Directive 91/6/76/EEC aims to ensure water quality by preventing pollution of surface and groundwater induced by nitrates originating from agricultural sources and by promoting agronomical good practices. While the implementation of this Directive seems effective, it appears however that the use of nitrogen has still increased by 6% over the last four years in 27 European countries. Furthermore, agricultural sources would be still at the origin of 50% of the total amount of nitrogen discharged into surface waters (http://ec.europa.eu/environment/water/water-nitrates/index_en.html). In Wallonia (Belgium), the Nitrates Directive has been transposed under the Sustainable Nitrogen Management in Agriculture Program (PGDA). Launched in 2002, it involves different sets of actions, like rules definitions concerning fertilizers application, specific and appropriate crop management in vulnerable areas, the control of potentially leachable nitrogen (APL) levels in soils, etc. This is the global context in which lies the present thesis. The main aim is to optimise the nitrogen fertiliser practices to ensure that the needs of a winter wheat culture (Triticum aestivum L.) could be met while reducing the environmental pressure. It relies on the use of crop models, which describe the growth and the development of a culture interacting with its environment, namely the soil and the atmosphere. The major difficulty while working with crop models and model-based decision support tools lies in the fact that different sources of uncertainties have an impact on the modelled phenomena. Indeed, crop models are constituted by a consequent number of differential non-linear equations, involving a lot of parameters which need to be determined as accurately as possible in order to match as close as possible observed sequences of measurements. The first source of uncertainty is thus constituted by the parameters definition. Once the model has been correctly and robustly calibrated it can be used to perform predictions. However, in an agronomical context, the time-delay between sowing and harvest is consequent. As the end-season yield is often the expected output, the uncertainty linked to the non-knowledge of the future implies for the modeller to refer to different hypothesis concerning upcoming climatic scenarios. Finally, moving from models to decision systems dealing with N management involves a last source of uncertainty. Indeed the main problem is that the impact of a given practice is delayed in time from its realisation. In addition to the uncertainty linked to climatic projections themselves, it is highly important to consider the interactions between the practices and the climate. Furthermore, in a decision-making process, it could be highly relevant to know the uncertainty's estimation that could be tolerated on the decision.. Therefore, the present thesis aims to study these different sources of uncertainty in order to design an efficient decision support system. It is divided into five parts. In the first part, a Bayesian sampling algorithm, known as DREAM (DiffeRential Evolution Adaptative Metropolis) will be presented. It was successfully coupled with the STICS soil-crop model used in this study. The a posteriori probability density function of many parameters was sampled in order to improve the simulations of the growth of a winter wheat culture (Triticum aestivum L.). The DREAM algorithm offers different advantages in comparison to usual methods. Among these, it is possible to study i) the most probable a posteriori parameters distributions, ii) the parameters correlations, and iii) the uncertainties impacted on model outputs. Furthermore, a new version of the likelihood function was proposed, making an explicit use of the coefficient of variation. Results showed that it allowed the noise existing on measurements to be considered, but also the heteroscedasticity phenomenon usually encountered in biological growth processes. In parallel, assimilation data is another way to improve models simulations. These techniques allow considering measurements performed in real-time (e.g. remote measures of LAI or soil water content) in order to correct and adjust the possible drift of model simulations. In particular, a recently developed algorithm, known as variational filter, was evaluated. Its superiority, both in term of state variables simulations improvement and parameter resampling, was demonstrated. The third part of the research focuses on the real-time end season yield prediction. It involves building climate matrix ensembles, combining different time ranges of projected mean data and real measured weather originating from the historical records. As the crop growing season progresses, the effects of real monitored data plays a greater role and the prediction reliability increases. Our results demonstrated that a reliable predictive delay of 3-4 weeks before harvest could be obtained. Finally, using real-time data acquired with a micrometeorological station enabled to (i) predict, daily, potential yield at the local level, (ii) detect stress occurrence, and (iii) quantify yield losses (or gains). Being based on projected seasonal norms, this methodology is in opposition to another technique that consists to offer a panel of solution for what concerns the future. Such probabilistic technique relies on the use of stochastic weather generator (LARS-WG in this case). However, in the fourth part of this thesis, on the basis of the convergence in law theorem, it was demonstrated that in 90% of the climatic situations, both approaches were equivalent, exhibiting RRMSE and normalised deviation criteria inferior to 10%. Furthermore the two approaches offered similar predictive delay-time. The main difference between techniques lies in the finality. The first allows to quickly simulate the remaining yield potential, while the second aims to quantify the uncertainty level associated to the predictions. In the fifth and last part of this thesis, in order to quantify the uncertainty level associated to different modalities of N applications, the STICS model answers were studied under stochastic climatic realisations. It was demonstrated that, if no N was applied, under our temperate climatic conditions, the yield distribution could be considered as normal. However, with increasing N practices, the asymmetry level was found itself increasing. As soon as N was applied, not only were the yields higher, but also was the probability to achieve yields that were at least superior to the mean of the distribution. This undoubtedly reduced the risk for the farmer to achieve low yields levels. To summary all the researches conducted in this thesis, a N strategic decision support system was developed. In a general way, for what concerns the Hesbaye Region, the superiority of three fractions N protocols was demonstrated. In addition, the three rates fertilisation management based on the systematic applications of 60 kgN.ha-1 at tillering and stem extension stages and offering the possibility to adapt the flag-leaf fraction in real-time appeared as an optimal strategy. Within this tool, the uncertainty associated to climatic variability could be finely characterised, and the risk encountered by the farmer was quantified for different investigated practices. But far more important, it was demonstrated that N management could be optimised in real-time. In a general way, the research should be pursued by studying more fundamentally and systematically a wide range of different agro-environmental situations. In particular, it would be interesting to study of the Genotype × Environment × Cultural practices interactions to ensure food security in a climatic changing world. [less ▲]Detailed reference viewed: 69 (27 ULg) Participation au Jury du Festival philosophique du Film "Eidolon" (concours "lycéens" et "pro")Herla, Anne Diverse speeche and writing (2014)Detailed reference viewed: 9 (0 ULg)