Search

Biogeography has been linked to differences in gut microbiota in several animals. However, the existence of such a relationship in fish is not clear yet. So far, it seems to depend on the fish species studied. However, most studies of fish gut microbiotas are based on single populations. In this study, we investigated the gut microbiota of fish from three wild populations of the two-banded sea bream Diplodus vulgaris (Geoffroy Saint-Hilaire, 1817) to determine whether its diversity, structure and potential functionality reflect the geographic origin of the fish, at large and small geographical scale. Additionally, we explored the host- and environmental-related factors explaining this relationship., SCOPUS: ar.j, info:eu-repo/semantics/published

Reliable protein detection methods are vital for advancing biological research and medical diagnostics. While immunohistochemistry and immunofluorescence are commonly employed, their limitations underscore the necessity for alternative approaches. This study introduces immunoplasmonic labelling, utilizing plasmonic nanoparticles (NPs), specifically designed gold and gold–silver alloy NPs (Au:Ag NPs), for multiplexed and quantitative protein detection. These NPs, when coupled with antibodies targeting proteins of interest, enable accurate counting and evaluation of protein expression levels while overcoming issues such as autofluorescence. In this study, we compare two nanoparticle functionalization strategies—one coating based on thiolated PEG and one coating based on calix[4]arenes—on gold and gold–silver alloy nanoparticles of varying sizes. Overall results tend to demonstrate a greater versatility for the calix[4]arene-based coating. With this coating and using the classical EDC/sulfo-NHS cross-linking procedure, we also demonstrate the successful multiplexed immunolabelling of Her2, CD44, and EpCAM in breast cancer cell lines (SK-BR-3 and MDA-MB-231). Furthermore, we introduce a user-friendly software for automatic NP detection and classification by colour, providing a promising proof-of-concept for the practical application of immunoplasmonic techniques in the quantitative analysis of biopsies in the clinical setting., info:eu-repo/semantics/published

info:eu-repo/semantics/published

info:eu-repo/semantics/published

Dans cette présentation, j'analyse 100 articles scientifiques français publiés de 2010 à 2022, axés sur le genre et la socialisation sexuelle. L'objectif est de décrypter les postulats sous-jacents à ces recherches concernant les différences entre individus homosexuels et hétérosexuels. Il ressort que nombre de ces études s'appuient sur des hypothèses fragiles. Cette présentation démontre comment les chercheurs attribuent une importance exagérée à l'orientation sexuelle, en établissant des dichotomies erronées et en surévaluant la portée de leurs résultats., info:eu-repo/semantics/inPress

Nematomorpha, also known as Gordiacea or Gordian worms, are a phylum of parasitic organisms that belong to the Ecdysozoa, a clade of invertebrate animals characterized by molting. They are one of the less scientifically studied animal phyla, and many aspects of their biology and evolution are still unknown, partially due to the lack of genomic resources for this phylum. As part of the European Reference Genome Atlas pilot effort to generate reference genomes for European biodiversity, we present the taxonomic description and chromosome-level genome assembly of a newly described species of Nematomorpha (Gordionus montsenyensis Schmidt-Rhaesa & Fernández sp. nov.). The final assembly has a total length of 288 Mb in 396 scaffolds with an N50 of 64.4 Mb, 97% of which is scaffolded into 5 pseudochromosomes. The circular mitochondrial genome was also assembled into a 15kilobases sequence. Gene annotation predicted 10,320 protein-coding genes in the nuclear genome. In this study, we contribute a key genomic resource to not only explore the evolution of Ecdysozoa, but also to further our understanding on the genomic basis of parasitic lifestyles. In addition, we describe a species new to science from this enigmatic animal phyla., SCOPUS: ar.j, info:eu-repo/semantics/published

0, info:eu-repo/semantics/published

Antony van Leeuwenhoek, "le père de la microbiologie", a découvert en 1702, à l'aide de son microscope, des créatures microscopiques uniques qu'il a ressuscitées en ajoutant de l'eau à de la litière de feuilles sèches. L'un de ces micro-organismes était un rotifère bdelloïde, l'un des plus petits animaux que l'on puisse trouver, mesurant moins d'un millimètre et comprenant environ 1 000 cellules. Ces petites créatures ont étonné van Leeuwenhoek parce qu'elles étaient encore vivantes après avoir réhydraté des feuilles gardées au sec pendant des mois. Les rotifères bdelloïdes sont des animaux remarquables pour leur capacité à survivre à la dessiccation à tous les stades de leur cycle de vie, mais aussi à résister à d'autres stress abiotiques, notamment la congélation et de fortes doses de radiations ionisantes. Lors de ces stress, les rotifères bdelloïdes arrêtent leur métabolisme de manière réversible et entrent dans un état d'animation suspendue appelé "tun". Lorsque les conditions sont favorables, ces animaux microscopiques sortent de l'état "tun" et reprennent leur mode de vie actif et hydraté, où ils continuent à se nourrir et à se reproduire de manière asexuée.Afin d'explorer la résistance au stress oxydatif chez les eucaryotes extrémotolérants, en se concentrant principalement sur l'espèce bdelloïde Adineta vaga, cette thèse comprend 4 chapitres principaux, brièvement détaillés ci-dessous.Chapitre 2 :Tolérance au stress extrême chez les eucaryotes :Réduire, sauver, recycler, Réparer et ÉliminerCette revue présente le concept de stress oxydatif, avec un accent particulier sur le stress oxydatif induit par les radiations et la dessiccation. Elle donne également un aperçu des réponses observées chez diverses espèces extrémotolérantes. Ces réponses sont classées comme suit :RÉDUIRE :se réfère principalement à une réduction des divisions cellulaires, également connue sous le nom d'eutely. SAUVEGARDE :consiste à sauver les macromolécules cellulaires actives par l'acc, Doctorat en Sciences, info:eu-repo/semantics/nonPublished

info:eu-repo/semantics/published

info:eu-repo/semantics/published

The Negombo Lagoon is a coastal lagoon influenced by local communities that introduce waste into its ecosystem. This study examined seven sewage entry points, out of which five sites were chosen for oyster sampling based on availability. Physicochemical and microbiological parameters of water (measured in triplicate at each site, n = 84) and oyster samples (total length, TL > 6 cm, n = 30) were assessed. Variation in regional coliform contamination was analyzed employing a one-way analysis of variance (ANOVA). Results indicated that the northern part of the lagoon exceeded recommended coliform thresholds for swimming (total coliform concentration (TCC) < 126 most probable number (MPN)) and seafood consumption (TCC < 100 MPN/g), indicating the presence of Escherichia coli. Water quality indices affirmed fecal pollution, except in the southern part of the lagoon. Furthermore, the study found high oyster consumption (76.7 %), elucidating that oysters from the northern part of Negombo Lagoon pose health risks., SCOPUS: ar.j, info:eu-repo/semantics/published

info:eu-repo/semantics/published

info:eu-repo/semantics/published

The synthesis of a series of mononuclear, dicationic CoII funnel complexes is reported herein. Three ligands Calix‐TMPAX present a calix[6]arene cone closed at its small rim by a tris(2‐pyridylmethyl)amine (TMPA) unit and differ by the nature of three cavity walls, anisole, phenol or quinone. The X‐ray diffraction structure of [CoII(MeCN)Calix‐TMPAOMe](ClO4)2 displays a trigonal bipyramidal geometry, with Co bound to all 4 nitrogen atoms of the TMPA cap, and to one MeCN guest molecule buried inside the calixarene cavity. All complexes were fully characterized in solution as high spin 5‐coordinate species using various techniques, including 1H NMR spectroscopy. For comparison purpose, an analogous CoII complex based on the TMPACH2OH ligand, devoid of a calixarene core, was synthetized. Its X‐ray structure shows a dicationic 7‐coordinate cobalt(II) center in the N4O3 environment provided by the ligand, leaving no space for exogenous ligand binding. This contrasts with the 5‐coordinate complexes obtained with the calix‐ligands that allow guest‐ligand binding and exchange. A brief overview of the coordination properties of the calix‐complexes, compared to those obtained with TMPA ligands, devoid of a cavity, highlights major differences in terms of complexation kinetics, geometry, coordination to the labile site, anion affinity, nuclearity, and stability., SCOPUS: ar.j, info:eu-repo/semantics/published

0, info:eu-repo/semantics/published

Increasing evidence points to the complex interplay of multiple genetic variants as a major contributing factor in many human diseases. Oligogenic diseases, in which a small set of genes collaborate to cause a pathology, present a compelling example of this phenomenon and necessitate a shift away from traditional single-gene inheritance models. Our work aimed to develop robust methods for pinpointing pathogenic combinations of genetic variants across patient cohorts, ultimately improving disease understanding and potentially guiding future diagnostic approaches.We began by developing a novel machine learning framework that integrates explainable AI (XAI) techniques and game-theoretic concepts. This framework allows us to classify and characterise different types of oligogenic effects, providing insights into the specific mechanisms by which multiple genes interact to drive disease. Next, we focused on refining existing computational methods used to predict the pathogenicity of variant combinations. Our emphasis was two-fold: improving computational efficiency for handling the expansive datasets associated with cohort analysis, and critically, reducing false-positive rates to ensure the reliability of our results. With these tools in hand, we developed a specialised cohort analysis approach tailored to investigating diseases with complex genetic origins. To demonstrate the capabilities of our methodology, we delved into a Marfan syndrome cohort. Marfan syndrome is a hereditary condition affecting the body's connective tissue. Our analysis successfully uncovered potential modifier mutations that appear to interact with the primary disease-causing variant, offering new clues about the intricate genetic landscape of this condition., Doctorat en Sciences, info:eu-repo/semantics/nonPublished

Ce travail de thèse concerne l’étude théorique des dommages radiatifs subis par l'acide désoxyribonucléique (ADN), qui jouent un rôle important dans des mécanismes tels que la carcinogenèse ou la mutagenèse.Notre étude est réalisée sur des systèmes moléculaires de taille réduite en phase gazeuse, en particulier sur des complexes formés par l’empilement de bases d’ADN successives d’un même brin (stackings). Pour ces systèmes, des méthodes de chimie quantique de haut niveau ont pu être utilisées afin de déterminer des surfaces d’énergie potentielle et les propriétés électroniques telles que le potentiel d'ionisation vertical.Ce manuscrit s'articule en trois grandes parties.La première partie replace ce travail de thèse dans son contexte général, en détaillant les dommages radiatifs, diverses notions biologiques sur l'ADN ainsi que les méthodes de chimie quantique utilisées.La seconde partie est consacrée à la détermination systématique du potentiel d'ionisation vertical (vIP) des stackings de deux à quatre bases d'ADN, à l’aide de la théorie de la fonctionnelle densité (DFT) et la méthode locale explicitement corrélée PNO-LCCSD(T)-F12 (explicitly correlated Pair Natural Orbital Local Coupled-Cluster). Au cours de nos calculs, l’influence de la séquence de bases d’ADN sur le vIP a été mise en évidence ainsi que les effets de taille des stackings.La troisième partie est consacrée au transfert de charge dans le stacking ionisé GGG+. À l'issue de nombreux tests méthodologiques réalisés sur des structures-test, nous avons établi une stratégie calculatoire basée sur les méthodes ab initio multi-configurationnelles. Notre niveau de calcul a permis d’étudier le transfert de la charge d’une guanine à une autre en fonction du mouvement de shift des guanines. La surface d'énergie potentielle a été calculée pour les deux premiers états électroniques du stacking GGG+. Ce travail ouvre la voie vers une étude approfondie de l'influence des autres paramètres conformationnels sur le s, Doctorat en Sciences, info:eu-repo/semantics/nonPublished

The objective of this research is to evaluate Landsat OLI/TIRS multi-spectral images, and fusion of GRASS GIS, GMT and QGIS software for land cover mapping in Guinea, West Africa. The scenes of Landsat imagery were acquired on February 2014, 2018 and 2023. Land cover data were used from FAO for validation of classes. The images were classified into 18 classes and upscaled to 10 classes for generalisation towards the study area regional setting. The method included K-means clustering using scripting approach with programming codes included in Appendix. The results demonstrated that the script-based computer vision approach to image processing, classification and analysis is effective in extracting land cover classes for environmental mapping of tropical region of West Africa., info:eu-repo/semantics/published

Mapping coastal regions is important for environmental assessment and for monitoring spatio-temporal changes. Although traditional cartographic methods using a geographic information system (GIS) are applicable in image classification, machine learning (ML) methods present more advantageous solutions for pattern-finding tasks such as the automated detection of landscape patches in heterogeneous landscapes. This study aimed to discriminate landscape patterns along the eastern coasts of Mozambique using the ML modules of a Geographic Resources Analysis Support System (GRASS) GIS. The random forest (RF) algorithm of the module 'r.learn.train' was used to map the coastal landscapes of the eastern shoreline of the Bight of Sofala, using remote sensing (RS) data at multiple temporal scales. The dataset included Landsat 8-9 OLI/TIRS imagery collected in the dry period during 2015, 2018, and 2023, which enabled the evaluation of temporal dynamics. The supervised classification of RS rasters was supported by the Scikit-Learn ML package of Python embedded in the GRASS GIS. The Bight of Sofala is characterized by diverse marine ecosystems dominated by swamp wetlands and mangrove forests located in the mixed saline-fresh waters along the eastern coast of Mozambique. This paper demonstrates the advantages of using ML for RS data classification in the environmental monitoring of coastal areas. The integration of Earth Observation data, processed using a decision tree classifier by ML methods and land cover characteristics enabled the detection of recent changes in the coastal ecosystem of Mozambique, East Africa., info:eu-repo/semantics/published

info:eu-repo/semantics/published

The variability of the Antarctic and Greenland ice sheets occurs on various timescales and is important for projections of sea level rise; however, there are substantial uncertainties concerning future ice-sheet mass changes. In this Review, we explore the degree to which short-term fluctuations and extreme glaciological events reflect the ice sheets’ long-term evolution and response to ongoing climate change. Short-term (decadal or shorter) variations in atmospheric or oceanic conditions can trigger amplifying feedbacks that increase the sensitivity of ice sheets to climate change. For example, variability in ocean-induced and atmosphere-induced melting can trigger ice thinning, retreat and/or collapse of ice shelves, grounding-line retreat, and ice flow acceleration. The Antarctic Ice Sheet is especially prone to increased melting and ice sheet collapse from warm ocean currents, which could be accentuated with increased climate variability. In Greenland both high and low melt anomalies have been observed since 2012, highlighting the influence of increased interannual climate variability on extreme glaciological events and ice sheet evolution. Failing to adequately account for such variability can result in biased projections of multi-decadal ice mass loss. Therefore, future research should aim to improve climate and ocean observations and models, and develop sophisticated ice sheet models that are directly constrained by observational records and can capture ice dynamical changes across various timescales., SCOPUS: re.j, info:eu-repo/semantics/published

Centrée au Pôle Sud, l’Antarctique constitue la plus grande étendue de glace continentale sur Terre,représentant le plus important réservoir d’eau douce. Cette masse de glace est constamment en mouvement.La glace se déforme sous l’action de la gravité, et glisse sur le substract rocheux sur lequel ellerepose. Depuis des années, l’Antarctique perd de la masse de glace en raison du réchauffement climatique.Les prédictions concernant l’évolution de sa masse de glace et sa contribution potentielle au niveau marinsont très incertaines. Une des principales sources d’incertitude réside dans comment exactement la glaceglisse-t-elle à la base? Le glissement basal inclut le glissement stricto sensu de la glace sur le lit rocheuxdans le cas d’un lit rigide, ainsi que la déformation du lit composé de sédiments dans le cas d’un lit déformable.Dans certaines zones, comme les ice streams, le glissement basal est le processus majoritaire dudéplacement de la glace. Les ice streams drainant la grande majorité de la calotte, il semble essentiel demieux comprendre le processus responsable de leur mouvement. Mathématiquement, le glissement basalest représenté par une loi de glissement reliant la vitesse du glacier à la contrainte exercée par celui-ci surle lit. Cette loi peut prendre plusieurs formes en fonction des phénomènes qu’elle englobe. L’eau sousglaciairejoue un rôle clef dans le glissement basal en lubrifiant le lit rocheux et en réduisant la résistance dusol à la déformation. Cette eau provient de la fonte de la glace à la base et s’organise en différents types desystèmes de drainage classés comme inefficaces ou efficaces. Les systèmes inefficaces se caractérisent parun faible flux en écoulement diffus, tandis que les systèmes efficaces présentent un fort flux en écoulementconcentré dans des conduits. Le premier objectif de cette thèse est de lier l’hydrologie sous-glaciaire auglissement basal à l’aide du modèle numérique Kori-ULB. Pour ce faire, nous évaluons quatre méthodesd, Centered at the South Pole, Antarctica constitutes the largest expanse of continental ice on Earth, representingthe most significant freshwater stock. This mass of ice is in constant motion, deforming underthe influence of gravity and sliding over the bedrock on which it is lying. Antarctica has been losing icemass for years due to global warming. Predictions regarding the evolution of its ice mass and its potentialcontribution to sea level rise are highly uncertain. One of the main sources of uncertainty lies in understandingexactly how the ice slides at the base. Basal sliding includes the sliding of the ice over the bedrockin the case of a hard bed, as well as the deformation of the bed composed of sediments in the case of adeformable and soft bed. In certain areas, such as ice streams, basal sliding is the predominant processin ice movement. As ice streams drain the majority of the ice sheet, it is essential to better understandthe process responsible for their motion. Mathematically, basal sliding is represented by a sliding law relatingthe glacier’s velocity to the stress it exerts on the bed. This law can take various forms dependingon the phenomena it encompasses. Subglacial water plays a key role in basal sliding by lubricating thebedrock and reducing the till’s resistance to deformation. This water comes from the melting of ice at thebase and organizes into different types of drainage systems classified as inefficient or efficient. Inefficientsystems are characterized by low-flow diffuse drainage, while efficient systems exhibit high-flow concentrateddrainage in conduits. The first objective of this thesis is to link subglacial hydrology to basal slidingusing the Kori-ULB numerical ice sheet model. To achieve this, we evaluate four methods developed inthe literature across the entire Antarctic ice sheet and compare them to simulations that do not considersubglacial hydrology. These methods differ in the representation of subglacial water: seawater pressure, Doctorat en Sciences, info:eu-repo/semantics/nonPublished

We use an observationally calibrated ice-sheet model to investigate the future trajectory of the Antarctic ice sheet related to uncertainties in the future balance between sub-shelf melting and ice discharge, on the one hand, and the surface mass balance, on the other. Our ensemble of simulations, forced by a panel of climate models from the sixth phase of the Coupled Model Intercomparison Project (CMIP6), suggests that the ocean will be the primary driver of short-term Antarctic mass loss, initiating ice loss in West Antarctica already during this century. The atmosphere initially plays a mitigating role through increased snowfall, leading to an Antarctic contribution to global mean sea-level rise by 2100 of 6 (−8 to 15) cm under a low-emission scenario and 5.5 (−10 to 16) cm under a very high-emission scenario. However, under the very high-emission pathway, the influence of the atmosphere shifts beyond the end of the century, becoming an amplifying driver of mass loss as the ice sheet's surface mass balance decreases. We show that this transition occurs when Antarctic near-surface warming exceeds a critical threshold of +7.5 ∘C, at which the increase in surface runoff outweighs the increase in snow accumulation, a signal that is amplified by the melt–elevation feedback. Therefore, under the very high-emission scenario, oceanic and atmospheric drivers are projected to result in a complete collapse of the West Antarctic ice sheet along with significant grounding-line retreat in the marine basins of the East Antarctic ice sheet, leading to a median global mean sea-level rise of 2.75 (6.95) m by 2300 (3000). Under a more sustainable socio-economic pathway, we find that the Antarctic ice sheet may still contribute to a median global mean sea-level rise of 0.62 (1.85) m by 2300 (3000). However, the rate of sea-level rise is significantly reduced as mass loss is likely to remain confined to the Amundsen Sea Embayment, where present-day climate conditions seem sufficient, info:eu-repo/semantics/published

In some areas of Antarctica, blue‐colored bare ice is exposed at the surface. These blue ice areas (BIAs) can trap meteorites or old ice and are vital for understanding the climatic history. By combining multi‐sensor remote sensing data (MODIS, RADARSAT‐2, and TanDEM‐X) in a deep learning framework, we map blue ice across the continent at 200‐m resolution. We use a novel methodology for image segmentation with “noisy” labels to learn an underlying “clean” pattern with a neural network. In total, BIAs cover ca. 140,000 km 2 (∼1%) of Antarctica, of which nearly 50% located within 20 km of the grounding line. There, the low albedo of blue ice enhances melt‐water production and its mapping is crucial for mass balance studies that determine the stability of the ice sheet. Moreover, the map provides input for fieldwork missions and can act as constraint for other geophysical mapping efforts., SCOPUS: ar.j, info:eu-repo/semantics/published

0, info:eu-repo/semantics/inPress

In this work we focus on the concept of optimization-by-continuation as a strategy for solving a set of optimization problems in about the time it would take to solve a single instance of them. Each cost function is a different linear combination of two convex terms, one differentiable and the other prox-simple. Such optimization problems occur frequently in the numerical solution of inverse problems (data misfit term plus penalty or constraint term), and the relative weight of both terms is often not known in advance. The algorithm's special feature lies in its ability to approximate, in a single iteration run, the minimizers of the cost function for many different values of the parameters determining the relative weight of the two terms. We also discuss the same problem in the presence of a third term in the cost function which is the combination of a prox-simple function and a linear map. As a special case, one recovers a generalization of the primal-dual algorithm of Chambolle and Pock., info:eu-repo/semantics/nonPublished

Le Marais Wiels se trouve sur le site des anciennes brasseries Wielemans. En termes écologiques, il s’inscrit dans le bas de la vallée de la Senne, un ensemble de zones humides caractérisées par la présence historique d’infrastructures ferroviaires et de sites industriels, à présent en majorité désaffectés. Depuis une dizaine d’années, le site s’est re-naturalisé à la faveur de travaux d’excavation qui ont provoqué la formation d’un étang permanent lié à la nappe phréatique et d’une roselière ainsi que la constitution d’une biodiversité caractéristique d’un marais (avifaune, amphibiens, odonates et hyménoptères). Ce qui apparaît comme une infrastructure écologique importante dans un quartier populaire et dense marqué par les inégalités sociales et environnementales (inondations, îlot de chaleur, accès limité aux espaces verts récréatifs, trafic de transit) est à présent menacé par un projet d’aménagement régional., info:eu-repo/semantics/inPress

Malgré le consensus croissant sur la nécessité d'une transition vers des pratiques agricoles plus durables, les céréales et, en particulier, le froment, ont pris du retard dans la conversion à l'agriculture biologique. Parmi les facteurs contribuant à ce retard figure le manque de variétés adaptées à ces pratiques agricoles et à leurs spécificités. Dans cette thèse, nous nous concentrons sur l’une des principales alternatives variétales pour répondre à ce problème :les populations hétérogènes. Par populations hétérogènes, nous désignons ici tout type de diversité intraspécifique, allant des mélanges variétaux jusqu’aux variétés-populations. Un avantage essentiel de cette hétérogénéité est que la présence de contrastes entre plantes peut donner lieu à des mécanismes de facilitation susceptibles d'améliorer les performances des cultures et leur stabilité face à des conditions défavorables. Malgré ces propriétés prometteuses, nous manquons cependant encore de clés pour guider ce type de sélection. Il s’agit là du principal objet de cette thèse.Ces dernières années, la recherche académique semble avoir mis l’accent sur la recherche d'associations de traits pouvant conduire aux mécanismes de facilitation que nous mentionnions ci-dessus. Dans ce travail, nous avons choisi de nous intéresser également à un autre type d'interaction qui a lieu au sein des populations hétérogènes :la compétition. En particulier, nous avons émis l'hypothèse qu'un certain type de compétition, que nous appelons « compétition individualiste », pourrait avoir des effets négatifs sur la culture. En effet, il arrive parfois que la sélection naturelle nous joue des tours en favorisant des individus qui ont pourtant un moindre potentiel de rendement, ou qui contribuent moins à la facilitation. Par conséquent, plus que la seule facilitation, le principal déterminant de la performance des populations hétérogènes pourrait plus précisément être l'équilibre entre compétition et facilitation. Dans les chapi, Despite the growing consensus on the need for a transition to more sustainable farming practices, cereals and, in particular, common wheat, have been lagging behind in the conversion to organic farming. We argue that one of the reasons for this is the lack of varieties that are adapted to these farming practices and their specificities. In this thesis, we focus on a main varietal alternative to respond to this issue: intra-crop diversity. By intra-crop diversity, we mean anything from variety mixtures to evolutionary populations, which we hereafter refer to with the umbrella term “heterogeneous stands”. One main advantage of intra-crop diversity is that trait contrasts between crop plants can give rise to facilitative mechanisms which can enhance crop performance and its stability in the face of unpredictable adverse conditions. However, we still know little about how to breed these heterogeneous stands. This is the main question that we try to address in this thesis.In recent years, a primary focus in the literature has been to identify favorable trait associations that can lead to facilitation. Here, we chose to also lend an eye to another type of plant interaction that unfolds in heterogeneous stands: competition. Indeed, we hypothesized that a specific type of competition, which we call “selfish competition”, could lead to negative effects on the crop. Sometimes, natural selection can indeed play tricks on us and favor genotypes that have lower grain yield potential or contribute less to facilitation. Hence, more than simply facilitation, it is the balance between competition and facilitation that may actually be the main determinant of heterogeneous stand performance. In chapters II and III, we thus sought to assess if selfish competition could indeed hinder heterogeneous stand performance, and to identify some of its underlying causes (with a focus on trait contrasts and sowing density). In agronomic trials with 12 variety mixtures and 2 Composite-Cross Popula, Doctorat en Sciences agronomiques et ingénierie biologique, info:eu-repo/semantics/nonPublished

This paper presents an R-based approach to mapping dynamics of the flooded areas in the Inner Niger Delta (IND), Mali, using time series analysis of Landsat 8-9 satellite images. As the largest inland wetland in West Africa, the habitats of IND offers high potential for biodiversity of the flood-dependent e c o systems. IND is one of the most productive areas in West Africa. Mapping flooded areas based on satellite images enables to provide strategies for land management and rice planting and modelling vegetation types of IND. Our approach is based on using libraries of R programming language for processing six Landsat images, and each image was taken on November from 2013 to 2022. By capturing spatial and temporal structures of the satellite images on 2013, 2015, 2018, 2020, 2021 and 2022, the remote sensing data are combined to yield estimates of landscape dynamics that is temporally coherent, while helping to analyse fluctuations of spatial extent in fluvial wetlands caused by the hydrological processes of seasonal flooding. Further, by allowing packages of R to support image processing, an approach to mapping vegetation by NDVI, SAVI and EVI indices and visualising changes in distribution of different land cover classes over time is realised. In this context, processing Earth observation data by advanced scripting tools of R language provides new insights into complex interlace of climate-hydrological processes and vegetation responses. Our study contributes to the sustainable management of natural resources and improving knowledge on the functioning of IND ecosystems in Mali, West Africa., SCOPUS: ar.j, SCOPUS: re.j, info:eu-repo/semantics/published

Background Islands are known to host unique flowering plant assemblages visited by insular insects, including by social bees, a phenomenon thought to potentially impact the honey composition and associated medicinal applications. In this study, we characterized several physical–chemical parameters of honey produced by the stingless bee Meliponula (Axestotrigona) ferruginea with samples collected both from continental (Kenya) and insular (Tanzania) ecosystems. Results Our results show that stingless bees in islands produce a honey whose composition significantly differs from those produced in the continent, with a significantly higher concentration of bioactive phytochemicals. Conclusion Our results illustrate how insularity might drive different and unique compositional profiles in honeys and provide evidence that certain groups of compounds found in stingless bee honey from the Afrotropical region have potential therapeutic benefits with medicinal applications that largely remain to be explored., info:eu-repo/semantics/published

info:eu-repo/semantics/published

We present a numerical iterative optimization algorithm for the minimization of a cost function consisting of a linear combination of three convex terms, one of which is differentiable, a second one is prox-simple and the third one is the composition of a linear map and a prox-simple function. The algorithm's special feature lies in its ability to approximate, in a single iteration run, the minimizers of the cost function for many different values of the parameters determining the relative weight of the three terms in the cost function. A proof of convergence of the algorithm, based on an inexact variable metric approach, is also provided. As a special case, one recovers a generalization of the primal-dual algorithm of Chambolle and Pock, and also of the proximal-gradient algorithm. Finally, we show how it is related to a primal-dual iterative algorithm based on inexact proximal evaluations of the non-smooth terms of the cost function., Submitted., info:eu-repo/semantics/inPress

info:eu-repo/semantics/nonPublished

Solid supported lipid bilayers (SLBs) are excellent platforms for studying the biophysical properties of cell membranes, as well as versatile biomimetic films for biotechnology applications. Among the existing approaches used to form SLBs, vesicle fusion and rupture onto solid supports is the most commonly employed one owing to its straightforward procedure. SLBs are typically formed on atomically flat and very hydrophilic surfaces, overlooking the influence of roughness and topography on membrane formation and organization. As a matter of fact, lipid bilayers in vivo are corrugated at the nanoscale level, as a result of interactions with proteins, fibrils, and other components within the intracellular and extracellular environment. Fundamental studies of the effect of surface roughness on SLBs are scarce and restricted to few contributions, where nanoroughness has shown to affect lipid mobility by a 5-fold decrease and inhibit domain growth in phase-separated membranes. In this work, the impact of nanoroughness on the formation and stability of SLBs onto SiO2 surfaces with different degrees of vertical and lateral surface roughness is studied. Combining quartz crystal microbalance with dissipation monitoring (QCM-D) and atomic force microscopy with force spectroscopy (AFM-FS), it is shown that nanoroughness affects the formation of SLBs by increasing the activation energy of vesicle fusion, rupture and spreading, and weakens the stability and lateral organization of the formed SLBs., info:eu-repo/semantics/published

info:eu-repo/semantics/nonPublished

info:eu-repo/semantics/published

info:eu-repo/semantics/inPress

info:eu-repo/semantics/published

Chronotherapy aims at optimising the time of day and dosing of drugs administration. This is a promising perspective because the toxicity and efficacy of many drugs show a dependence on the time of the day at which they are administrated. Efficient cancer chronotherapy requires a good understanding of the interplay between the cell cycle and the circadian clock. Computational models offer a way to study the dynamics resulting from the coupling between these two biological oscillators and to predict successful therapeutic protocols. We review here recent advances and highlight key challenges for further developments of predictive mathematical models., SCOPUS: re.j, info:eu-repo/semantics/published

info:eu-repo/semantics/nonPublished

More than 60% of meteorite finds on Earth originate from Antarctica. Using a data-driven analysis that identifies meteorite-rich sites in Antarctica, we show climate warming causes many extraterrestrial rocks to be lost from the surface by melting into the ice sheet. At present, approximately 5,000 meteorites become inaccessible per year (versus ~1,000 finds per year) and, independent of the emissions scenario, ~24% will be lost by 2050, potentially rising to ∼76% by 2100 under a high-emissions scenario., SCOPUS: ar.j, info:eu-repo/semantics/published

info:eu-repo/semantics/nonPublished

info:eu-repo/semantics/nonPublished

Provenance records from sediments deposited offshore of the West Antarctic Ice Sheet (WAIS) can help identify past major ice retreat, thus constraining ice‐sheet models projecting future sea‐level rise. Interpretations from such records are, however, hampered by the ice obscuring Antarctica's geology. Here, we explore central West Antarctica's subglacial geology using basal debris from within the Byrd ice core, drilled to the bed in 1968. Sand grain microtextures and a high kaolinite content (∼38–42%) reveal the debris consists predominantly of eroded sedimentary detritus, likely deposited initially in a warm, pre‐Oligocene, subaerial environment. Detrital hornblende 40 Ar/ 39 Ar ages suggest proximal late Cenozoic subglacial volcanism. The debris has a distinct provenance signature, with: common Permian‐Early Jurassic mineral grains; absent early Ross Orogeny grains; a high kaolinite content; and high 143 Nd/ 144 Nd and low 87 Sr/ 86 Sr ratios. Detecting this “fingerprint” in Antarctic sedimentary records could imply major WAIS retreat, revealing the WAIS's sensitivity to future warming., info:eu-repo/semantics/published

Nitrogen is an essential component of all living organisms and a basic element for synthesizing many chemical products. However, N2 is chemically inert and inaccessible to most organisms in its original form. Therefore, it must be first converted into other more reactive forms like ammonia or nitrates in a process named “Nitrogen Fixation”. Nitrogen fixation (NF) with low energy consumption and minimal CO2 emissions is a significant challenge in today's technological landscape. The natural processes allowing NF are mostly lightning and the activity of some bacteria. The global population growth also increases food demands, thus the industrialization of agriculture using nitrogen-based fertilizers has driven the development of artificial NF processes. In the beginning of the 20th century, intensive research efforts led to the development of several industrial NF processes. The most developed processes are (I) Birkeland–Eyde (B-E) process, (II) Frank–Carlo (F-C) process, and (III) Haber–Bosch (H-B) process. As a result of high energy consumption, the first two processes were abandoned and quickly replaced by the H-B process. In the H-B process, nitrogen from air is combined with hydrogen during steam methane reforming under extremely high pressures (100−250 bar) and moderately high temperatures (500°C) in presence of an active catalyst (Fe or Ru–based catalysts) to yield a high proportion of ammonia. For a fully optimized and integrated H-B process, an energy efficiency as low as 0.48 MJ/mol of nitrogen is reported. Nevertheless, despite its effectiveness, this process consumes almost 1%–2% of the world’s total energy resources and emits more than 180 million tons of CO2 annually. In addition, a fully operational H-B process demands a large infrastructure that does not allow for decentralization on a small scale which makes the transportation requirement an additional disadvantage of this method. It is therefore necessary to develop a new NF process allowing for lower en, Doctorat en Sciences de l'ingénieur et technologie, info:eu-repo/semantics/nonPublished

Termites are amongst the most abundant and ecologically-important groups of insects in tropical forests. However, the destructive potential of some species amounts to billions of dollars in damage each year. Despite their economic and ecological impacts, only a limited number of invasive termite species have been studied using distribution modelling and no studies have taken trade, transport and demography variables into account. We used Species Distribution Models (SDMs) to investigate the potential distribution of 10 highly-invasive termites. Our study includes bioclimatic conditions, land-use patterns, elevation and connectivity predictors (i.e. urban areas, human population, accessibility to cities and private vessels), alongside different climatic and socioeconomic change scenarios.The distribution of the termite species hinges on bioclimatic and connectivity variables, highlighting the significance of these latter factors in invasive species analyses. Our models demonstrate the potential of these invasive termites to thrive in large urbanised and connected areas within tropical and subtropical regions and to a lesser extent within temperate regions. As climate changes and urbanisation intensifies, most species’ range could expand, particularly under a “fossil fuel-driven development” scenario. Furthermore, while some species may have a slightly reduced range, they could extend their presence into more urbanised and connected areas, increasing the risks and costs associated with termite damages. Our models highlight the anticipated role of growing connectivity and climate change dynamics in facilitating the widespread proliferation of invasive termites in the coming years., SCOPUS: ar.j, info:eu-repo/semantics/published

The kinetics of spontaneous monomer transfer between vesicles consisting of zwitterionic phospholipids is dictated by the difference in desorption rate of lipid monomers from their donor vesicles and the concentration imbalance in the dispersion. In a system with two lipid species with the same headgroup, transfer is asymmetric, and takes place from the population of donor vesicles consisting of shorter chain lipids to acceptor ones of longer chain. Transfer typically proceeds until equilibrium is reached, resulting in populations of vesicles consisting of a binary mixture of both lipid species, whose concentration depends on the number of lipids in the precursor donor and acceptor vesicles before transfer.Upon the introduction of a second lipid species in the donor vesicle population, the desorption rate of monomers should change with time, since the composition of donor vesicles changes when monomers of a given lipid type desorb. To tackle this problem, we added a cationic lipid, 1,2-dimyristoyl-3-trimethylammonium-propane (DMTAP), into donor zwitterionic lipid vesicles and assessed how the concentration of DMTAP affects the lipid transfer process. Lipid transfer is the result of the interplay between the initial concentration of DMTAP in the donor vesicles (and related probability of desorption at short transfer times) and their concomitant time-dependent concentration (and thus desorption rate) change due to the depletion of monomer species as the transfer process proceeds., info:eu-repo/semantics/published

The study of biogenic structures (e.g. lebensspuren) produced by benthic fauna on the seafloor provides invaluable information about the behavior of their tracemakers. In the case of sea stars, most of the previous research has been focused on shallow-marine environments due to the extreme scarcity of data from deep-sea lebensspurens. Here, we examined sea star traces from six deep-sea stations (deeper than 4500 m) near the Aleutian Trench (North Pacific). A total of six families were identified from still images. The majority of them were not observed producing any lebensspuren or just pentameral impressions related to resting and feeding activities. Two members of the families Pterasteridae and Porcellanasteridae could be clearly characterized by a composite behavior resulting in contrasting lebensspuren morphotypes. A morphotype belonging to the genus Hymenaster undet .produced pentameral impressions (related to predation) and punctuated trails (related to podia locomotion). Members of the family Porcellanasteridae produced oval to circular impressions (that may be related to burrowing trails for the detection of organic matter), flat-shallow trails (related to podia locomotion), and irregular M-ridged trails (related to locomotion while feeding through the sediment interface). There is a severe scarcity of data related to the locomotion of past deep-sea Asteroidea (i.e. trace fossils) and their ichnotaxonomical classification. We discuss the implications of our results for the ichnofamily Biformitidae, as well as the importance of considering other features (e.g. podia impressions) rather than just hook-shaped traces related to arm locomotion., SCOPUS: ar.j, info:eu-repo/semantics/published

Myoelectric prostheses have recently shown significant promise for restoring hand function in individuals with upper limb loss or deficiencies, driven by advances in machine learning and increasingly accessible bioelectrical signal acquisition devices. Here, we first introduce and validate a novel experimental paradigm using a virtual reality headset equipped with hand-tracking capabilities to facilitate the recordings of synchronized EMG signals and hand pose estimation. Using both the phasic and tonic EMG components of data acquired through the proposed paradigm, we compare hand gesture classification pipelines based on standard signal processing features, convolutional neural networks, and covariance matrices with Riemannian geometry computed from raw or xDAWN-filtered EMG signals. We demonstrate the performance of the latter for gesture classification using EMG signals. We further hypothesize that introducing physiological knowledge in machine learning models will enhance their performances, leading to better myoelectric prosthesis control. We demonstrate the potential of this approach by using the neurophysiological integration of the “move command" to better separate the phasic and tonic components of the EMG signals, significantly improving the performance of sustained posture recognition. These results pave the way for the development of new cutting-edge machine learning techniques, likely refined by neurophysiology, that will further improve the decoding of real-time natural gestures and, ultimately, the control of myoelectric prostheses., SCOPUS: ar.j, info:eu-repo/semantics/published

info:eu-repo/semantics/nonPublished