Presenting the Sámi when learning Norwegian. An analysis of the representation of the Sámi in Norwegian as a Foreign and Second Language textbooks.

This thesis explores the representation of Sámi people in the textbooks used by foreigners to learn Norwegian. The research aims at identifying the different approaches used from the 1940s until the late 2010s to present Sámi people in Norwegian as Foreign Language textbooks and the factors influencing their presentation through a historical and sociocultural perspective. To do so, this research also describes the emergence and the evolution of the field of Norwegian as a Foreign and Second Language and and the textbooks it produced

Théorèmes limites pour les sommes de Birkhoff de fonctions d'intégrale nulle en théorie ergodique en mesure infinie

Ce travail est consacré à certaines classes de systèmes dynamiques ergodiques, munis d'une mesure invariante infinie, telles que des applications de l'intervalle avec un point fixe neutre ou des marches aléatoires. Le comportement asymptotique des sommes de Birkhoff d'observables d'intégrale non nulle est assez bien connu, pour peu que le système ait une certaine forme d'hyperbolicité. Une situation particulièrement intéressante est celle des tours au-dessus d'une application Gibbs-Markov. Nous cherchons dans ce contexte à étudier le cas d'observables d'intégrale nulle. Nous obtenons ainsi une forme de théorème central limite pour des systèmes dynamiques munis d'une mesure infinie. Après avoir introduit l'ensemble des notions nécessaires, nous adaptons des résultats de E. Csáki et A. Földes sur les marches aléatoires au cas des applications Gibbs-Markov. Les théorèmes d'indépendance asymptotique qui en découlent forment le cœur de cette thèse, et permettent de démontrer un théorème central limite généralisé. Quelques variations sur l'énoncé de ce théorème sont obtenues. Ensuite, nous abordons les processus en temps continu, tels que des semi-flots et des flots. Un premier travail consiste à étudier les propriété en temps grand du temps de premier retour et du temps local pour des extensions de systèmes dynamiques, ce qui se fait par des méthodes spectrales. Enfin, par réductions successives, nous pouvons obtenir une version du théorème central limite pour des flots périodiques, et en particulier le flot géodésique sur le fibré tangent unitaire de certaines variétés périodiques hyperboliques.This work is focused on some classes of ergodic dynamical systems endowed with an infinite invariant measure, such as transformations of the interval with a neutral fixed point or random walks. The asymptotic behavior of the Birkhoff sums of observables with a non-zero integral is well known, as long as the system shows some kind of hyperbolicity. The towers over a Gibbs-Markov map are especially interesting. In this context, we aim to study the case of observables whose integral is zero. We get the equivalent of a central limit theorem for some dynamical systems endowed with an infinite measure. After we introduce the necessary definitions, we adapt some results by E. Csáki and A. Földes on random walks to the case of Gibbs-Markov maps. We derive a theorem on the asymptotic independence of Birhoff sums, which is the core of this thesis, and from this point we work out a generalised central limit theorem. We also prove a few variations on this generalised central limit theorem. Then, we study dynamical systems in continuous time, such as semi-flows and flows. We first work on the asymptotic properties of the first return time and the local time for extensions of dynamical systems; this is done by spectral methods. Finally, step by step, we extend our generalised central limit theorem to cover some periodic flows, and in particular the geodesic flow on the unitary tangent bundle of some hyperbolic periodic manifolds.RENNES1-Bibl. électronique (352382106) / SudocSudocFranceF

Paving the way towards future-proofing our crops

To meet the increasing global demand for food, feed, fibre and other plant-derived products, a steep increase in crop productivity is a scientifically and technically challenging imperative. The CropBooster-P project, a response to the H2020 call ‘Future proofing our plants’, is developing a roadmap for plant research to improve crops critical for the future of European agriculture by increasing crop yield, nutritional quality, value for non-food applications and sustainability. However, if we want to efficiently improve crop production in Europe and prioritize methods for crop trait improvement in the coming years, we need to take into account future socio-economic, technological and global developments, including numerous policy and socio-economic challenges and constraints. Based on a wide range of possible global trends and key uncertainties, we developed four extreme future learning scenarios that depict complementary future developments. Here, we elaborate on how the scenarios could inform and direct future plant research, and we aim to highlight the crop improvement approaches that could be the most promising or appropriate within each of these four future world scenarios. Moreover, we discuss some key plant technology options that would need to be developed further to meet the needs of multiple future learning scenarios, such as improving methods for breeding and genetic engineering. In addition, other diverse platforms of food production may offer unrealized potential, such as underutilized terrestrial and aquatic species as alternative sources of nutrition and biomass production. We demonstrate that although several methods or traits could facilitate a more efficient crop production system in some of the scenarios, others may offer great potential in all four of the future learning scenarios. Altogether, this indicates that depending on which future we are heading toward, distinct plant research fields should be given priority if we are to meet our food, feed and non-food biomass production needs in the coming decades

Presenting the Sámi when learning Norwegian. An analysis of the representation of the Sámi in Norwegian as a Foreign and Second Language textbooks.

This thesis explores the representation of Sámi people in the textbooks used by foreigners to learn Norwegian. The research aims at identifying the different approaches used from the 1940s until the late 2010s to present Sámi people in Norwegian as Foreign Language textbooks and the factors influencing their presentation through a historical and sociocultural perspective. To do so, this research also describes the emergence and the evolution of the field of Norwegian as a Foreign and Second Language and and the textbooks it produced

Approches de génétique moléculaire et de protéomique pour l'analyse de l'homéostasie métallique chez Arabidopsis thaliana

Chez les plantes, les transporteurs de métaux jouent des rôles essentiels dans l'homéostasie métallique. Pour comprendre les liens entre le transport des métaux essentiels et la détoxication des métaux nocifs chez Arabidopsis, nous avons développé deux stratégies différentes: d'une part une approche ciblée pour comprendre la fonction des transporteurs de métaux AtNRAMP et, d'autre part, une approche de protéomique comparative pour identifier sans a priori de nouvelles protéines de la membrane plasmique régulées lors d'un stress par le cadmium.Les protéines NRAMP sont capables de transporter des métaux essentiels comme le Fe et le Mn et des métaux toxiques comme le cadmium. En associant des approches de génétique moléculaire, de biologie cellulaire et de biochimie, nous avons montré qu'AtNRAMP3 et AtNRAMP4 sont des protéines tonoplastiques. Pendant la germination, elles sont essentielles pour mobiliser les réserves de fer alors que chez la plante adulte, elles permettent le recyclage du Mn à partir de la vacuole. De plus, ces transporteurs jouent un rôle en réponse au stress oxydatif. La membrane plasmique représente la première interface en contact avec le cadmium. Pour identifier de nouvelles protéines membranaires impliquées dans les fonctions de perception, d'acquisition et d'exclusion du cadmium, nous avons développé une stratégie de protéomique quantitative reposant sur un marquage métabolique des cellules d'Arabidopsis thaliana par le 15N. L'analyse comparative entre les protéomes de la membrane plasmique de cellules stressées ou non par le cadmium est en cours. Quelques protéines candidates induites par le cadmium ont déjà été identifiées.In plants, metal transporters play major roles in intracellular metal homeostasis. Many metal transporters are able to transport essential metal as well as toxic metals. To understand the relationship between the transport of essential metals and the detoxification of noxious metals in Arabidopsis, we have used two strategies: a targeted approach with the aim to elucidate the function of NRAMP metal transporters and a global proteomic approach to identify novel plasma membrane proteins regulated under cadmium stress.NRAMP are able to transport a broad range of metals such as Fe, Mn and Cd. Using a combination of molecular genetic, cell biological and analytical approaches, we have shown that AtNRAMP3 and AtNRAMP4 are vacuolar membrane proteins with several redundant functions: during seed germination they are essential to mobilize vacuolar Fe stores while in adult plant they are required to recycle Mn from the vacuole. In addition, the nramp3nramp4 double mutant is also hypersensitive to the oxidative stress generated by cadmium and AtNRAMP3 and AtNRAMP4 accumulates after an oxidative stress. These proteins could be involved in the supply of metal cofactors to reactive oxygen species detoxifying enzymes. The plasma membrane is the first interface where Cd stress is perceived and where cadmium may be taken up or extruded from the cell. In order to characterize novel intrinsic proteins involved in these functions, we have developed a comparative proteomic strategy based on 15N metabolic labeling of Arabidopsis cell. Comparative analysis of the plasma membrane proteome is under way and we have already identified candidate proteins regulated by Cd.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Handing off iron to the next generation: how does it get into seeds and what for?

To ensure the success of the new generation in annual species, the mother plant transfers a large proportion of the nutrients it has accumulated during its vegetative life to the next generation through its seeds. Iron (Fe) is required in large amounts to provide the energy and redox power to sustain seedling growth. However, free Fe is highly toxic as it leads to the generation of reactive oxygen species. Fe must, therefore, be tightly bound to chelating molecules to allow seed survival for long periods of time without oxidative damage. Nevertheless, when conditions are favorable, the seed's Fe stores have to be readily remobilized to achieve the transition toward active photosynthesis before the seedling becomes able to take up Fe from the environment. This is likely critical for the vigor of the young plant. Seeds constitute an important dietary source of Fe, which is essential for human health. Understanding the mechanisms of Fe storage in seeds is a key to improve their Fe content and availability in order to fight Fe deficiency. Seed longevity, germination efficiency and seedling vigor are also important traits that may be affected by the chemical form under which Fe is stored. In this review, we summarize the current knowledge on seed Fe loading during development, long-term storage and remobilization upon germination. We highlight how this knowledge may help seed Fe biofortification and discuss how Fe storage may affect the seed quality and germination efficiency

Mechanotransduction in the spotlight of mechano-sensitive channels: Plant mechano-sensitive channels

International audienceThe study of mechanosensitive channels (MS) in living organisms has progressed considerably over the past two decades. The understanding of their roles in mechanosensation and mechanotransduction was consecrated by the awarding of the Nobel Prize in 2021 to A. Patapoutian for his discoveries on the role of MS channels in mechanoperception in humans. In this review, we first summarize the fundamental properties of MS channels and their mode of operation. Then in a second step, we provide an update on the knowledge on the families of MS channels identified in plants and the roles and functions that have been attributed to them

Calcium and plasma membrane force-gated ion channels behind development

International audienceDuring development, tissues are submitted to high variation of compression and tension forces. The roles of the cell wall, the cytoskeleton, the turgor pressure and the cell geometry during this process have received due attention. In contrast, apart from its role in the establishment of turgor pressure, the involvement of the plasma membrane as a transducer of mechanical forces during development has been under studied. Force-gated (FG) or Mechanosensitive (MS) ion channels embedded in the bilayer represent 'per se' archetypal mechanosensor able to directly and instantaneously transduce membrane forces into electrical and calcium signals. We discuss here how their fine-tuning, combined with their ability to detect micro-curvature and local membrane tension, allows FG channels to transduce mechanical cues into developmental signals

Plant science: the key to preventing slow cadmium poisoning

info:eu-repo/semantics/publishe