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See detailWild boar movement ecology across scales: Insights from a population expanding into agroecosystems of Southern Belgium
Morelle, Kevin ULg

Doctoral thesis (2015)

Over the time, ungulates have seen their populations continuously changing under the e ect of direct, i.e. hunting pressure, and indirect, i.e. land-use changes, human activities. Under control until ... [more ▼]

Over the time, ungulates have seen their populations continuously changing under the e ect of direct, i.e. hunting pressure, and indirect, i.e. land-use changes, human activities. Under control until recently, ungulates have progressively adapted to these modi cations and are now able to cope with human-shaped environments, consequently their number and range have greatly and worryingly increased. More particularly, among ungulates species, the wild boar Sus scrofa raises important concerns due to its environmental, economic and social impacts on modern societies. Understanding the ecology of ungulates species and their ability to survive within highly dynamic and seasonal ecosystems, such as agricultural environment, is thus necessary to better mitigate their negative impacts and to sustainably manage growing and expanding populations. Although only recently studied, movement ecology of animal is an important species trait that allows animal to adapt to rapid environmental changes. Considering movement as the resulting interaction of the animal’s internal state, navigation and motion capacity as well as of the e ect of the surrounding environment (“external factors”), provides a clear conceptual framework enabling to study patterns, mechanisms and processes, such as coping with land-use changes. In this thesis, we study the case of an expanding wild boar population in Southern Belgium and consider the movement ecology of the species to understand how wild boar colonize and ourish in agroecosystems. More speci cally, the thesis aims at i) reviewing quantitatively and qualitatively the scienti c literature about wild boar movement ecology, and ii) analyzing the spatial response of wild boar to agroecosystems in terms of movement and habitat selection across three spatial and temporal scales. The literature review highlights that wild boar is the least studied ungulates species in terms of movement ecology.We suggest that this is likely due i) to the relative complexity of tting tracking devices to this species, and ii) to its generalist diet making the species not suitable to test foraging hypotheses. Among existing studies, a large part focuses on the role of external factors (e.g. hunting, landscape features) on movement while others components of the movement ecology framework (internal state, navigation and motion capacity) remain poorly studied. However, when assuming behavioral similarity between wild and domestic boars, experimental studies on captive animals show how wild boar can develop complex movement strategies by using their highly developed cognitive and sensory abilities, and spatial memory. The spatio-temporal analysis suggests a scale-speci c response of wild boar to agricultural habitat. At the intermediate scale (landscape, seasonal), wild boar uses seasonal habitat shift strategies towards agricultural areas, while at broader scale (regional, decades), wild boar avoids this habitat, preferring the forest habitat to spread and extend its occupancy range. This results in a contradiction with our preliminary hypothesis that increased area of cultivations providing cover (maize, rapeseed, cereals) facilitates wild boar population expansion. Furthermore, we show that besides the use of forest habitat, high population density is a major driving factor of the colonization of agroecosystems by wild boar. The ne-scale analysis (home range, daily), highlights the large variety of spatial behaviors (area restricted search, central place foraging, nomadism, dispersing) wild boar is able to use to cope with heterogeneous environments. In terms of management of the species, the results of this thesis suggest that it is required to lower the population density in order to limit the population spread into agroecosystems, not only at the margin of expansion but all over the species’ range. Furthermore, we recommend developing more exible control strategies taking into account both the spatial abilities of the species and the complexity and dynamics of the environment. For example, the creation of a seasonal landscape of fear could be promoted, i.e. reducing attractivity of agricultural lands by increasing risk sensation (e.g. hunting with dogs all along the growing season). However, in our opinion, the success of any management strategy requires rst to tackle the issue of the decreasing number of hunters observed in large part of Europe and to improve communication among the di erent stakeholders (hunting associations, farmers, public administration). Indeed, while ungulates have progressively adapted to human-induced changes, the capacity of humans to adapt to this new human-ungulate relation is questionable. [less ▲]

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See detailPerturbations de l'épissage des ARN pré-messagers par les agents chimiothérapeutiques: mécanismes d'action du cisplatine et impact sur la mortalité des cellules cancéreuses
Gabriel, Maude ULg

Doctoral thesis (2015)

L’épissage alternatif est un processus qui concerne plus de 90% des pré-ARN messagers et qui contribue largement à la diversité protéique. Il est régulé par une série de facteurs d’épissage qui se lient ... [more ▼]

L’épissage alternatif est un processus qui concerne plus de 90% des pré-ARN messagers et qui contribue largement à la diversité protéique. Il est régulé par une série de facteurs d’épissage qui se lient sur des séquences situées sur les transcrits primaires. L’activité de ces facteurs d’épissage est régulée, entre autres, par divers signaux externes et voies de signalisation.  Les agents chimiothérapeutiques peuvent altérer la régulation de l’épissage et, ainsi, modifier la séquence d’un grand nombre d’ARN messagers et, éventuellement, la fonction des protéines qui en résultent. Cependant, l’implication de ces mécanismes dans la thérapie anticancéreuse demeure mal connue en termes d’efficacité thérapeutique, de diagnostic, de pronostic, de développement de résistances aux traitements et d’induction d’effets secondaires. L’objectif principal de cette étude est d’évaluer si la régulation de l’épissage par le cisplatine est critique pour son activité anticancéreuse. L’analyse du transcriptome de cellules mammaires cancéreuses traitées avec du cisplatine a permis d’identifier de nombreuses altérations d’épissage induites par la chimiothérapie. Parmi les 700 évènements observés, un grand nombre touche des transcrits impliqués dans le cycle cellulaire et dans la régulation de l’épissage lui-même.   Bien que le cisplatine induise des dommages au niveau de l’ADN, nous avons exclu la participation des membres de la voie des dommages à l’ADN, tels que ATM, ATR, DNA-PK et p53, dans les altérations d’épissage induites par le cisplatine. Les PI3K de class I (p110) et la voie MEK/ERK sont , en revanche, requises.  L’utilisation d’une banque de plus de 50 siRNA ciblant des protéines se liant à l’ARN, en particulier des facteurs d’épissage, nous a permis d’évaluer l’implication de ces facteurs dans les modifications d’épissage observées après le traitement au cisplatine. Il est apparu que la réduction de l’expression de certains facteurs dont SF3A1, RBM39, U2AF1 et snRNP70 mime les effets du cisplatine. A l’inverse, l’inhibition de SRSF4 réprime ces effets.  Par co-immunoprécipitation, nous avons observé un lien physique entre le facteur de transcription c-Jun et les facteurs d’épissage SF3A1 et RBM39. Alors que cette liaison ne semble pas être affectée par le cisplatine, des modifications du statut de phosphorylation de c-Jun ont été observées après traitement au cisplatine. La déplétion de c-Jun et l’inhibition d’AP-1 corrigent en partie l’effet du cisplatine sur l’épissage, suggérant leur implication dans le processus.   Finalement, nous avons montré que la déplétion en SRSF4 réduit la mortalité cellulaire induite par le cisplatine, alors que la déplétion en SF3A1 et RBM39 l’augmente. Ces résultats montrent une corrélation entre épissage et mort cellulaire et suggèrent que la modulation de l’épissage pourrait être utilisée comme thérapie adjuvante afin d’augmenter l’efficacité de la chimiothérapie.   [less ▲]

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See detailEtude du potentiel des sous produits de la filière vinicole pour des applications à haute valeur ajoutée
Berchem, Thomas ULg

Master's dissertation (2015)

Nowadays, there is no longer any doubt about the future fossil fuels rarefaction. It is necessary to find more sustainable ways to produce everyday consumer products faced to an increasing population. Bio ... [more ▼]

Nowadays, there is no longer any doubt about the future fossil fuels rarefaction. It is necessary to find more sustainable ways to produce everyday consumer products faced to an increasing population. Bio-based chemistry and bio-refining are alternative solutions deserving a particular attention. The large amount of green waste produced all around the world represents energy and chemical resources with an under-exploited potential. Wine-making byproducts come from grape growing which is one of the largest crop around world. It seems to be an interesting source of bio-based molecules but, despite this potential, these byproducts are untapped. Their uses are limited to poor value added applications like composting, agricultural spreading or bioethanol. This work focuses on the high value added valorization possibilities of the wine-making byproducts. It takes part in the current trend of using natural bioactive molecules in pharmaceutical, parapharmaceutical or food industry. This study is built around three main objectives: a characterization of the raw material and the development of a method to extract polyphenols. The results shown in this work tend to indicate a high valorization potential of grape pomace thank to the identification of interesting compounds like bioactive molecules and especially polyphenols as well as high concentrations of other molecules of which the valorization potential from wine-making byproducts needs to be explored. [less ▲]

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Peer Reviewed
See detailComparative transcriptomic analysis of the distinct pancreatic cell types
Peers, Bernard ULg

Conference (2015, June 28)

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See detailMultiscale structure characterization of sawdust-waste water sludge extrudates dried in a pilot-scale fixed bed
Li, Jie ULg; Plougonven, Erwan ULg; Fraikin, Laurent ULg et al

in Biomass and Bioenergy (2015), 81(0), 98-107

Abstract Convective drying of waste water sludge and sawdust-sludge mixtures in a pilot-scale fixed bed was studied. Drying was performed in a cross-flow convective dryer using 500 g of wet material ... [more ▼]

Abstract Convective drying of waste water sludge and sawdust-sludge mixtures in a pilot-scale fixed bed was studied. Drying was performed in a cross-flow convective dryer using 500 g of wet material extruded through a disk with circular dies 12 mm in diameter. The structure of the bed mainly shows volume shrinkage and crack formation during drying. Several characterization techniques were used over a wide range of scales from nm up to mm. The overall bed structure was imaged with X-ray macrotomography, at a resolution of 0.36 mm per pixel. Single extrudates were scanned with X-ray microtomography, at a resolution of 41 μm per pixel. Pore structure of the dried samples were characterized by mercury porosimetry (7.5 nm < dp < 150 μm). Results show significant structural changes on all scales with increasing amounts of sawdust: shrinkage decreases, crack formation increases, and the pores become larger. This confirms the benefits of sawdust addition for sludge drying applications. [less ▲]

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See detailRiga. Une capitale balte à l'époque de l'Art nouveau
Folville, Xavier ULg

Conference given outside the academic context (2015)

Au début du XVIIIe siècle, Riga, ancienne ville hanséatique, faisait partie de l'empire tsariste dont elle était un des ports les plus importants ; elle connut une histoire compliquée et douloureuse ... [more ▼]

Au début du XVIIIe siècle, Riga, ancienne ville hanséatique, faisait partie de l'empire tsariste dont elle était un des ports les plus importants ; elle connut une histoire compliquée et douloureuse, partagée avec les autres pays baltes. A la fin du XIXe siècle, la destruction des anciens remparts facilite son extension sur de nouveaux territoires et permet de répondre à l'explosion démographique et au développement économique du moment. Au tournant du siècle, l’Art nouveau s’impose comme le style moderne qui correspond à une ville dynamique. Mais ici, c’est un Art nouveau très différent de celui que nous connaissons à Bruxelles. Teinté de symbolisme dans sa décoration, animé par un sentiment de renouveau national, d’esprit romantique, il engendre des immeubles, des rues, voire des quartiers entiers ou des palais qui seront édifiés jusqu’à la Première Guerre mondiale. Riga, consciente de son patrimoine, est reconnue par l’Unesco ; de nombreux bâtiments sont restaurés et un musée-témoin de l’art de vivre à cette époque est ouvert au public. La conférence propose de faire une courte promenade illustrée dans ce patrimoine. [less ▲]

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See detailEnergetics and Structural Characterization of Isomers Using Ion Mobility and Gas-phase H/D Exchange: Learning from Lasso Peptides
Hanozin, Emeline ULg; Morsa, Denis ULg; De Pauw, Edwin ULg

in Proteomics (2015), early view

State-of-the-art characterization of proteins using mass spectrometry namely relies on fragmentation methods which allows exploring featured dissociative reaction pathways. These pathways are often ... [more ▼]

State-of-the-art characterization of proteins using mass spectrometry namely relies on fragmentation methods which allows exploring featured dissociative reaction pathways. These pathways are often initiated by a series of potentially informative mass-constant conformational changes that are nonetheless frequently overlooked by lack of adequate investigation techniques. In the present study, we propose a methodology to readily address both structural and energetic aspects of stereoisomerization reactions using ion mobility coupled with mass spectrometry. To this end, a commercial spectrometer was used as a reactor comprising an energy resolved collisional activation step intended at promoting controlled conformational changes and a structural assignment step dedicated to the identification of the generated isomers. This identification relies on ion mobility and other on-line coupled techniques, namely an originally designed gas-phase H/D exchange experiment. We here apply this methodology to characterize the isomerization kinetics of capistruin, a 19-residue long lasso-folded peptide. We expect this approach to bring insights into the physical origin of global dissociation thresholds monitored in tandem mass spectrometry experiments and to set a promising basis for quantitative investigations of the stability of different molecular folds. [less ▲]

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See detailAssessment of climate change effects on groundwater resource in transient conditions
Goderniaux, Pascal; Wildemeersch, Samuel; Brouyère, Serge ULg et al

Conference (2015, June 27)

A sophisticated transient weather generator (WG) in combination with an integrated surface-subsurface hydrological model (HydroGeoSphere) are used for producing a stochastic generation of large numbers of ... [more ▼]

A sophisticated transient weather generator (WG) in combination with an integrated surface-subsurface hydrological model (HydroGeoSphere) are used for producing a stochastic generation of large numbers of equiprobable climatic time series, representing transient climate change, and assess impacts on groundwater resources in a probabilistic way. The modelling approach, involving the catchment-scale fully integrated surface-subsurface model, is described in Goderniaux et al. [2009]. Biased-corrected climate change scenarios are applied as input of the hydrological model to quantify their impact on groundwater resources. In Goderniaux et al. [2011], the integrated model is used in combination with a stochastic daily weather generator (WG). This WG allowed generating a large number of equiprobable climate change scenarios representative of a full transient climate between 2010 and 2085. These scenarios enabled to account for the transient nature of the future climate change, and to assess the uncertainty related to the weather natural variability. The downscaling method considers changes in the climatic means, but also in the distribution of wet and dry days. This new methodology is applied for the unconfined chalky aquifer of the Geer catchment in Belgium. A general decrease of the mean groundwater piezometric heads, has been calculated. The approach allowed also to assess different uncertainty sources: (1) the uncertainty linked to the calibration of the hydrological model, using 'UCODE_2005'; (2) the uncertainty linked to the global and regional climatic models (GCMs and RCMs), by using a multi-model ensemble; (3) the uncertainty linked to the natural variability of the weather, by using stochastic climate change scenarios. 30 equiprobable climate change scenarios from 2010 to 2085 have been generated for each of 6 different RCMs. Results show that although the 95% confidence intervals calculated around projected groundwater levels remain large, the climate change signal becomes stronger than that of natural climate variability by 2085. The WG ability to simulate transient climate change enabled the assessment of the likely timescale and associated uncertainty of a specific impact. This methodology constitutes a real improvement in the field of groundwater projections under transient climate change conditions as it enables water managers to analyse risks and take decisions with full knowledge of projected impact and their degree of confidence. [less ▲]

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See detailDUSP3 Phosphatase Deficiency or Inhibition Limits Platelet Activation and Arterial Thrombosis
Tautz, Lutz; Rahmouni, Souad ULg; Oury, Cécile ULg et al

Conference (2015, June 27)

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See detailTime-domain simulation of large electric power systems using domain-decomposition and parallel processing methods
Aristidou, Petros ULg

Doctoral thesis (2015)

Dynamic simulation studies are used to analyze the behavior of power systems after a disturbance has occurred. Over the last decades, they have become indispensable to anyone involved in power system ... [more ▼]

Dynamic simulation studies are used to analyze the behavior of power systems after a disturbance has occurred. Over the last decades, they have become indispensable to anyone involved in power system planning, control, operation, and security. Transmission system operators depend on fast and accurate dynamic simulations to train their personnel, analyze large sets of scenarios, assess the security of the network in real-time, and schedule the day ahead operation. In addition, those designing future power systems depend on dynamic simulations to evaluate proposed reinforcements, whether these involve adding new transmission lines, increasing renewable energy sources, or implementing new control schemes. Even though almost all computers are now parallel, power system dynamic simulators are still based on monolithic, circuit-based, single-process algorithms. This is mainly due to legacy code, written in the 80's, that is still today in the core of the most important commercial tools and does not allow them to fully exploit the parallel computational resources of modern computers. In this thesis, two parallel algorithms belonging to the family of Domain Decomposition Methods are developed to tackle the computational complexity of power system dynamic simulations. The first proposed algorithm is focused on accelerating the dynamic simulation of large interconnected systems; while, the second algorithm aims at accelerating dynamic simulations of large combined transmission and distribution systems. Both proposed algorithms employ non-overlapping decomposition schemes to partition the power system model and expose parallelism. Then, “divide-and-conquer” techniques are utilized and adapted to exploit this parallelism. These algorithms allow the full usage of parallel processing resources available in modern, inexpensive, multi-core machines to accelerate the dynamic simulations. In addition, some numerical acceleration techniques are proposed to further speed-up the parallel simulations with little or no impact on accuracy. All the techniques proposed and developed in this thesis have been thoroughly tested on academic systems, a large real-life system, and a realistic system representative of the continental European synchronous grid. The investigations were performed on a large multi-core machine, set up for the needs of this work, as well as on two multi-core laptops computers. [less ▲]

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See detailTowards the identification of cis-elements responsible for the high expression of HMA4, an essential gene for Zn hyperaccumulation in Arabidopsis halleri.
Spielmann, Julien ULg; Nouet, Cécile ULg; Scheepers, Maxime ULg et al

Conference (2015, June 26)

A. halleri is a Zn and Cd hypertolerant and hyperaccumulator plant which stores metals in shoot vacuoles. One key step for hyperaccumulation is a highly efficient root-to-shoot translocation of metals ... [more ▼]

A. halleri is a Zn and Cd hypertolerant and hyperaccumulator plant which stores metals in shoot vacuoles. One key step for hyperaccumulation is a highly efficient root-to-shoot translocation of metals. The Zn/Cd plasmamembrane pump HMA4 (heavy metal ATPase 4) plays a central role in this process and is involved in xylem loading/unloading. Moreover, HMA4 is overexpressed in A. halleri compare to its non-tolerant and non-hyperaccumulator sister, Arabidopsis thaliana. The HMA4 overexpression is determined by a combination of gene triplication and cis-regulatory changes increasing transcription levels of each three HMA4 copies. In this study, we are focusing on the two most active HMA4 promoters and we aim to identify the cis-elements underlying high expression of HMA4 in A. halleri using promoter-reporter constructs. Through deletion analysis, two important regions for a high expression have been identified. Ongoing analysis of more detailed deletions will be presented. [less ▲]

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See detailInfluence of terroir on the fungal assemblages associated to common bean seed
Klaedtke, Stephanie ULg; Jacques, Marie-Agnès; Chable, Véronique et al

Conference (2015, June 25)

Plants have evolved in association with microbial assemblages, also known as microbiota, which can affect plant growth and health. In contrast with other plant habitats, microbiota associated to seeds ... [more ▼]

Plants have evolved in association with microbial assemblages, also known as microbiota, which can affect plant growth and health. In contrast with other plant habitats, microbiota associated to seeds have only recently become an object of research. First surveys reveal that seed-associated microbial assemblages are composed of 50 to 1000 bacterial and fungal operational taxonomic units (OTUs) (Barret et al., 2015), including plant pathogens. Common bean (Phaseolus vulgaris L.) is affected by several seed-borne pathogens representing a phytosanitary challenge for common bean seed production. In a participatory research project (Farm Seed Opportunities, a European FP6 project), small scale organic seed producers emitted the hypothesis that seed microbiota in their integrity, including pathogens, play a role in shaping the crop as it adapts to local environments, leading to more resilience (Döring et al., 2014). As a first step to investigating this hypothesis, we analyzed 27 bean seed samples to assess whether the seed microbiota are indeed site-dependant or in contrary transmitted from on plant generation to the next within each cultivar. [less ▲]

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See detailIs western lowland gorilla a good gardener? Effect of fecal matrix and deposition at nest sites on seedling growth
Haurez, Barbara ULg; Brostaux, Yves ULg; Petre, Charles-Albert ULg et al

Conference (2015, June 25)

The Western lowland gorilla is a key dispersal agent, which disperses viable seeds of various size. In consequence of its nesting behavior, gorilla deposits half of its feces, and therefore about half of ... [more ▼]

The Western lowland gorilla is a key dispersal agent, which disperses viable seeds of various size. In consequence of its nesting behavior, gorilla deposits half of its feces, and therefore about half of dispersed seeds, at nest sites. This study was conducted in a logging concession of southeast Gabon where 78 % of the observed nest sites (n=183) were installed in open canopy terra firma forest. The aim of this research was to assess if seed deposition by gorillas (i) in fecal matrix and (ii) at nest sites is advantageous for seedling growth. To assess the effect of fecal matrix, seeds of Santiria trimera (Burseraceae), Chrysophyllum lacourtianum (Sapotaceae) and Plagiostyles africana (Euphorbiaceae) collected in gorilla feces were sown with and without fecal matrix in a nursery at the study site. The impact of seed deposition at nest sites on seedling growth was evaluated in situ. Seedlings of Santiria trimera and Dacryodes normandii (Burseraceae) were installed at nest sites and at closed canopy terra firma forest sites. For both type of trials, seedling growth was monitored. [less ▲]

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See detailCaractéristiques des patchs dans les herbiers à Posidonia oceanica. Origine naturelle versus origine anthropique
Abadie, Arnaud ULg

Scientific conference (2015, June 25)

La plante marine endémique de Méditerranée Posidonia oceanica, ou posidonie, forme en Corse des herbiers colonisant les substrats depuis la surface jusqu’à 40 m de profondeur. Ces herbiers constituent un ... [more ▼]

La plante marine endémique de Méditerranée Posidonia oceanica, ou posidonie, forme en Corse des herbiers colonisant les substrats depuis la surface jusqu’à 40 m de profondeur. Ces herbiers constituent un véritable écosystème, l’un des plus riches en espèces de Méditerranée. Ils sont notamment soumis à des phénomènes de fragmentation naturels (hydrodynamisme) et anthropiques (par exemple l’ancrage, le chalutage, la pollution) à l’origine de la formation de patchs (ou "intermattes"), créant des zones de contact entre habitats de nature disparate. Issus de phénomènes différents, les patchs auront ainsi des caractéristiques et une dynamique propre. Les présents travaux de recherche ont été réalisés en baie de Calvi à 15 m de profondeur et visent à comparer les caractéristiques de patchs naturels générés par l’hydrodynamisme, et de patchs anthropiques issus de l’ancrage intensif. Dans cette optique, un patch de chaque type a été sélectionné et cartographié par triangulation à l’aide de balises afin d’étudier précisément leur dynamique spatiale. Les patchs au sein des herbiers à P. oceanica étant en grande partie composés de sédiments, le flux de déposition des particules a été étudié à l’aide de pièges à sédiments. Les caractéristiques chimiques du sédiment ayant une importante influence sur le développement de la posidonie, l’oxygène (O2), un composé vital, et le sulfure d’hydrogène (H2S), un composé létal, ont été mesurés à différentes profondeurs dans la couche sédimentaire et comparés avec les valeurs obtenues dans l’herbier adjacent. Des données ont été récoltées en hiver et en été afin de prendre en compte la variation saisonnière des phénomènes biotiques et abiotiques. Le suivi de la dynamique spatiale des patchs montre que, concernant le patch naturel, l’érosion de l’herbier (-10,3 cm.a-1) est compensée par sa colonisation (+10,1 cm.a-1), alors qu’une très grande proportion du patch d’ancrage (64 %) est érodée. Le flux de particules dans les patchs est de façon générale très faible en été (de 1,71 à 4,45 gDW.m-².d-1) par rapport à l’hiver (de 32,17 à 91,48 gDW.m-².d-1). Le dépôt total de particule est beaucoup plus important au sein du patch d’ancrage en hiver. Les deux patchs montrent des profils de concentration en oxygène et en sulfure d’hydrogène dans le sédiment similaire en hiver et contrastés en été, avec une concentration importante en sulfure dans le patch d’ancrage (9,3 µM à 10 cm de profondeur), limitant la potentielle recolonisation par l’herbier environnant. [less ▲]

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See detailRobustifier nos analyses de données: un must!
Aerts, Stéphanie ULg

Conference given outside the academic context (2015)

Financiers, biologistes, psychologues, économistes ou chimistes,… tous utilisent des outils statistiques pour prédire, expliquer, modéliser, comprendre des processus spécifiques à leur domaine. Néanmoins ... [more ▼]

Financiers, biologistes, psychologues, économistes ou chimistes,… tous utilisent des outils statistiques pour prédire, expliquer, modéliser, comprendre des processus spécifiques à leur domaine. Néanmoins, les résultats de toute analyse statistique, de la plus simple à la plus complexe, peuvent être fortement influencés, voire renversés, par la présence d’une seule valeur atypique. S’il est assez aisé de surmonter ce problème pour de simples ensembles de données, lorsque plusieurs caractéristiques sont mesurées simultanément, disposer de méthodes robustes nécessite l’emploi d’algorithmes alliant à la puissance actuelle de nos ordinateurs, des théorèmes mathématiques parfois vieux de plus de 50 ans. A l’heure où on dispose de bases de données de plus en plus grandes mais de qualité inégale, il est indispensable que les praticiens se familiarisent avec les statistiques robustes afin de fiabiliser leurs conclusions. [less ▲]

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