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See detailÉvolution géomorphologique du littoral occidental de la péninsule tingitane (Maroc)
El Abdellaoui, Jamal ULg

Doctoral thesis (2014)

This work traces the geomorphological evolution of the western coast of the tingitane Peninsula (Morocco) in two time scales: the current scale and the Quaternary scale. Geomorphological characteristics ... [more ▼]

This work traces the geomorphological evolution of the western coast of the tingitane Peninsula (Morocco) in two time scales: the current scale and the Quaternary scale. Geomorphological characteristics have been identified and placed into their morphotectonic and/or morphodynamic contexts. To make our work more interesting, fruitful and realistic, we adopted an empirical approach. Firstly, we based our research on collection of data and analysis of available documents. Secondly, we made measurements, using appropriate techniques to answer specific questions, or to argue the hypotheses. It appears from this study, that the organization of geological units in a NNW-SSE direction has created a rugged shore, mainly in rocky cliff and pocket beaches on the Strait of Gibraltar coast, and a low sandy coast on the Atlantic coast. The geological and geomorphological quaternary history of Gibraltar Strait coast is characterized by a series of marine abrasion stepped and raised surfaces. The history of the Atlantic coast is rather marked by tectonic subsidence. This tectonic subsidence is manifested on the surface by a system of closed depressions (daya) arranged in a NNW-SSE axis, almost parallel to the orientation of geological units. The evolution of the geomorphological depressions is also controlled by the fluvio-marine action and wind activity. The last interglacial period is marked by two transgressive pulsations of eustatic origin. They were recorded at the marine terraces on both coasts. The second pulsation is aged at least 119.6 ± 2.3 ky. After the last interglacial, the central area of the Strait of Gibraltar was raised by an average of 8.1mm/100year from 117ky. The Ouljien was raised to a height of 13 to 16m. The Atlantic coast was stable at 117ky. Marine terraces are 5-6m high. The analysis shows that the current morphodynamics of the Atlantic coast are characterized by a barred beach geomorphology with a high spatio-temporal variability. It appears that a land wind plays a key role in the morphosedimentary evolution of backshore and foreshore. Indeed, the backshore develops, by negative retroaction, a geomorphology with a dune system to slow transport operated by land winds from the east. The foreshore, meanwhile, develops, by a positive retroaction, a system of bar and rip channels to counter a change in slope generated by the wind. On the one hand, risk analysis shows that the succession of anthropic changes at Tangier Bay has brooked the internal sediment balance. Erosion has affected both the sandy and rugged beaches of the eastern sector. The Atlantic coast doesn’t show signs of erosion, but it has a high vulnerability, because it evolves in a closed sedimentary system. On the other hand, the characteristic of a low open ocean coast facilitates the penetration of marine waters within the continent, especially the lower areas. Finally, a barred beach geomorphology creates problems of harbor silting and access disruption. [less ▲]

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See detailForest radiative transfer models: which approach for which application?
Ligot, Gauthier ULg; Balandier, Philippe; Courbaud, Benoît et al

in Canadian Journal of Forest Research = Journal Canadien de la Recherche Forestière (2014), 44(5), 385-397

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See detailOutplacement adequacy and benefits: The mediating role of retrospective justice
Marzucco, Laurence ULg; Hansez, Isabelle ULg

Poster (2014, May)

ABSTRACT We examined the relationships between perceived outplacement adequacy, retrospective justice and outplacement benefits for redundant employees using outplacement services. Based on an ... [more ▼]

ABSTRACT We examined the relationships between perceived outplacement adequacy, retrospective justice and outplacement benefits for redundant employees using outplacement services. Based on an outplacement experience perceived as adequate, victims formed retrospective justice perceptions about their former organization that in turn, impacted their negative emotions, well-being, future perspectives and job search. PRESS PARAGRAPH The increasing prevalence of organizational downsizing has been matched by growth in the provision of outplacement services over the last decade. Despite this rapid growth and ongoing need for outplacement services, little is yet known about the perceived adequacy and the benefits of these services for redundant employees using them. Our results indicated that an outplacement experience perceived as adequate for redundant employees retrospectively fosters their impressions of justice about the dismissing organization; this leads in turn to satisfactory benefits for them: reduction of negative emotions, enhancement of their perceived well-being, future perspectives, and job-seeking activities. [less ▲]

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See detailEvent justice and social entity justice: A cross-lagged analysis
Marzucco, Laurence ULg; Hansez, Isabelle ULg

Poster (2014, May)

ABSTRACT This study aimed to examine the directionality of the relationship between event justice and social entity justice. Using two samples and a cross-lagged panel analysis with two measurement times ... [more ▼]

ABSTRACT This study aimed to examine the directionality of the relationship between event justice and social entity justice. Using two samples and a cross-lagged panel analysis with two measurement times, social entity justice was found to predict event justice (procedural, distributive, interpersonal and informational justice event), supporting the top-down process. PRESS PARAGRAPH The life of organizations is punctuated by a wide range of managerial decisions (e.g., hiring, performance appraisal or organizational change). Facing such events, employees evaluate the fairness of the situation experienced. However, little is known about how employees develop justice judgments. This study shows that employees’ fairness perceptions about their organization influence their interpretation of the fairness of subsequent events involving the organization. Building and fostering a climate of justice is therefore of primary importance for organizations, since global fairness perceptions about the organization may help employees to perceive a specific event, such as a managerial decision, as being fair. [less ▲]

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See detailAzione, testualizzazione, notazione
Dondero, Maria Giulia ULg

in Pezzini, Isabella; Spaziante, Lucio (Eds.) Arti del vivere e semiotica (2014)

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See detailWork-home interference and well-being: A cross-lagged analysis.
Babic, Audrey ULg; Stinglhamber, Florence; Barbier, Marie ULg et al

Poster (2014, May)

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See detailL'enfant placé au carrefour de ses appartenances
Aubinet, Suzanne ULg

Poster (2014, May)

Michard (2009) nous dit de la loyauté qu’elle est l’armature de l’appartenance et à Neuburger de souligner qu’en plus d’être un socle sur lequel l’identité se structure, l’appartenance contient et limite ... [more ▼]

Michard (2009) nous dit de la loyauté qu’elle est l’armature de l’appartenance et à Neuburger de souligner qu’en plus d’être un socle sur lequel l’identité se structure, l’appartenance contient et limite les effets des relations (2003). Pour Onnis (2008) c’est dans la dialectique entre identité et appartenance que naît l’individualité qui, elle, se réalise dans la relation (Dolto, 1988). Plymackers (2006) insiste sur les notions d’espaces où se nouent ces relations mais aussi de temps où ces dernières se jouent. L’enfant, par des mouvements dialectiques d’allées et venues avec son/ses système(s) d’appartenances tisse pas à pas les prémices de son identité. Ses relations structurent et étayent ce processus et la temporalité constitue le squelette de celui-ci. Mais qu’en est-il de ces enfants placés, maltraités, déplacés ? Qu’en est-il si le conflit ou le clivage de loyauté entre famille(s) et institution(s) rend l’étayage de l’appartenance ardu ? Qu’en est-il si la discontinuité des espaces et des relations prédomine et si le processus d’individuation est suspendu par une séparation arbitraire dictée par un autrui qui « n’appartient pas » ? L’analyse clinique de cas d’enfants aux vécus chaotiques rythmés par de nombreux placements nous permet de décortiquer les particularités de ce processus complexifié par ces ruptures d’espaces, ces loyautés morcelées, ces appartenances diffuses et d’en cerner les impacts. [less ▲]

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See detailThe XMM-Newton view of the yellow hypergiant IRC+10420 and its surroundings
De Becker, Michaël ULg; Hutsemekers, Damien ULg; Gosset, Eric ULg

in New Astronomy (2014), 29

Among evolved massive stars likely in transition to the Wolf-Rayet phase, IRC +10420 is probably one of the most enigmatic. It belongs to the category of yellow hypergiants and it is characterized by ... [more ▼]

Among evolved massive stars likely in transition to the Wolf-Rayet phase, IRC +10420 is probably one of the most enigmatic. It belongs to the category of yellow hypergiants and it is characterized by quite high mass loss episodes. Even though IRC+10420 benefited of many observations in several wavelength domains, it has never been a target for an X-ray observatory. We report here on the very first dedicated observation of IRC+10420 in X-rays, using the XMM-Newton satellite. Even though the target is not detected, we derive X-ray flux upper limits of the order of 1–3 ×10−14 erg cm−2 s−1 (between 0.3 and 10.0 keV), and we discuss the case of IRC+10420 in the framework of emission models likely to be adequate for such an object. Using the Optical/UV Monitor on board XMM-Newton, we present the very first upper limits of the flux density of IRC +10420 in the UV domain (between 1800 and 2250 Å and between 2050 and 2450 Å). Finally, we also report on the detection in this field of 10 X-ray and 7 UV point sources, and we briefly discuss their properties and potential counterparts at longer wavelengths. [less ▲]

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See detailEntre recettes du Soi et recettes de l'Autre. Ethnographie de pratiques culinaires marocaines à Sesto San Giovanni (Milan, Italie)
Mescoli, Elsa ULg

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 ▲]

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See detailControl of attosecond electronic dynamics in molecules
Mignolet, Benoît ULg

Doctoral thesis (2014)

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See detailMicrofossils’ diversity from the Proterozoic Taoudeni Basin, Mauritania
Beghin, Jérémie ULg; Javaux, Emmanuelle ULg; Houzay, Jean-Pierre et al

in European Geosciences Union General Assembly 2014 Vienna, Austria, 27 April – 02 May 2014 (abstract book) (2014, April 27)

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See detailIntroduction aux travaux de Luciano Del Pistoia : corps et psychose
Englebert, Jérôme ULg

Scientific conference (2014, April 25)

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See detailPredicting Grain Protein Content of Winter Wheat
Mansouri, Majdi ULg; Dumont, Benjamin ULg; Destain, Marie-France ULg

in ESANN 2014 Proceedings (2014, April 24)

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See detailA Frequency-domain Approach to Subspace Identification of Nonlinear Systems, Application to Aerospace Structures
Noël, Jean-Philippe ULg

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 ▲]

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See detailIncertitudes liées à la modélisation agro-environnementale en vue de développer des outils d'aide à la décision
Dumont, Benjamin ULg

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 ▲]

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