258 research outputs found
La Història pren els actors seriosament?
Se señala el olvido de la problemática de la actuación libre de la persona en historiografia francesa moderna, y se reivindica la importancia de la misma. Se analiza brevemente el ejemplo de los Conseils de Prud'hommes de la Francia de la Restauración, y se concluye defendiendo la conveniencia de un enfoque historiográfico en el que la el estado de una sociedad aparezca determinada por las decisiones libres y múltiples de los individuos.Lepetit points out the problem of personal freedom of acts' oblivion in the modern French historiography and he vindicates the importante of this factor. He also analyses the example of the Conseils de Prud'hommes in the time of the Restoration in France and he Jinishes his article advocating for the conveniente of an approach that would consider the state of a society as determined for personal (free and multiple) choices
Understanding interface effects in perovskite thin films
The control of matter properties (transport, magnetic, dielectric,...) using
synthesis as thin films is strongly hindered by the lack of reliable theories,
able to guide the design of new systems, through the understanding of the
interface effects and of the way the substrate constraints are imposed to the
material. The present paper analyses the energetic contributions at the
interfaces, and proposes a model describing the microscopic mechanisms
governing the interactions at an epitaxial interface between a manganite and
another transition metal oxide in perovskite structure (as for instance ). The model is checked against experimental results and literature
analysis
Javaslatok az interdiszciplinaritás szűkĂtett Ă©rtelmezĂ©sĂ©hez : Propositions pour une pratique restreinte de PinterdisciplinaritĂ©
Pour une nouvelle histoire sociale
Le temps paraît venu d'une redéfinition (provisoire, mais non éphémère) de l'histoire sociale. La conjoncture y est propice. A l'interieur de l'histoire et parmi les disciplines voisines, des propositions émergent qui présentent les mêmes caractères : attention croissante à l'action située, aux constructions identitaires, à l'ordonnancement temporel des phénomènes. On propose donc d'explorer une nouvelle alliance qui associerait, au sein de la discipline, convention, lien social, historicité ..
Large increase of the Curie temperature by orbital ordering control
Using first principle calculations we showed that the Curie temperature of
manganites thin films can be increased by far more than an order of magnitude
by applying appropriate strains. Our main breakthrough is that the control of
the orbital ordering responsible for the spectacular increase cannot be
imposed by the substrate only. Indeed, the strains, first applied by the
substrate, need to be maintained over the growth direction by the alternation
of the manganite layers with another appropriate material. Following these
theoretical findings, we synthesized such super-lattices and verified our
theoretical predictions
La ville : cadre, objet, sujet
En France, l’histoire urbaine, depuis une vingtaine d’années, n’est pas simplement un domaine nouveau qui a connu une vive expansion. Désignée un temps comme une voie pour sortir l’histoire sociale des années soixante d’une impasse historiographique, la ville s’affirme dans les années soixante-dix comme un objet de recherche autonome, au moment où l’histoire urbaine tend à se constituer en histoire problème. Contre une approche limitée à la description des groupes sociaux, cette dernière s’intéresse désormais davantage aux réseaux, aux stratégies, aux situations, aux processus, faisant progressivement émerger la créativité des phénomènes citadins et, par la même, la ville comme un véritable sujet de l’histoire.In France, urban history since the last twenty years is not simply a new field which has known a brisk expansion. Considered for some time as a way of extricating social history of the sixties from a historiographical impasse, the city affirmed itself in the seventies as an object of independent research at a moment when urban history was attempting to organize itself as a problematic history. As against an approach limited to the description of social groups, urban history henceforth concerned itself more with networks, strategies, situations or processes, gradually bringing to light the creativity of the phenomenon of town life, and at the same time the city as a true subject of history
La société comme un tout : sur trois formes d'analyse de la totalité sociale
Comment faire une histoire totale ? Autrement dit, comment rendre compte, à partir de la conduite individuelle des acteurs (du côté de l'objet) et d'enquêtes empiriques nécessairement limitées (du côté des méthodes) de la totalité sociale et des processus macro-historiques ? Au moins dans l'historiographie française, la réponse ne va plus de soi. D'une part, les historiens qui se réclament des Annales sont fréquemment accusés, depuis plusieurs années, d'avoir oublié le projet d'histoire total..
Prey preference in a kleptoplastic dinoflagellate is linked to photosynthetic performance
Dinoflagellates of the family Kryptoperidiniaceae, known as “dinotoms”, possess diatom-derived endosymbionts and contain individuals at three successive evolutionary stages: a transiently maintained kleptoplastic stage; a stage containing multiple permanently maintained diatom endosymbionts; and a further permanent stage containing a single diatom endosymbiont. Kleptoplastic dinotoms were discovered only recently, in Durinskia capensis; until now it has not been investigated kleptoplastic behavior and the metabolic and genetic integration of host and prey. Here, we show D. capensis is able to use various diatom species as kleptoplastids and exhibits different photosynthetic capacities depending on the diatom species. This is in contrast with the prey diatoms in their free-living stage, as there are no differences in their photosynthetic capacities. Complete photosynthesis including both the light reactions and the Calvin cycle remain active only when D. capensis feeds on its habitual associate, the “essential” diatom Nitzschia captiva. The organelles of another edible diatom, N. inconspicua, are preserved intact after ingestion by D. capensis and expresses the psbC gene of the photosynthetic light reaction, while RuBisCO gene expression is lost. Our results indicate that edible but non-essential, “supplemental” diatoms are used by D. capensis for producing ATP and NADPH, but not for carbon fixation. D. capensis has established a species-specifically designed metabolic system allowing carbon fixation to be performed only by its essential diatoms. The ability of D. capensis to ingest supplemental diatoms as kleptoplastids may be a flexible ecological strategy, to use these diatoms as “emergency supplies” while no essential diatoms are available.Open Access funding enabled and organized by Projekt DEAL.We are grateful to Dr Benjamin Bailleul for discussing the photoactivity possibility of N. inconspicua, and to Prof Dieter Spiteller and Dr Adrien Lapointe for suggesting the feeding experiment of D. capensis with four selected diatoms. We also thank Dr Martin Stöckl, from the Bioimaging Centre at University of Konstanz, for technical support of the CLSM. Our thanks also go to Ms Selina Pucher and Mr Alexander H. Fürst for discussing the RT-qPCR data analyses and evaluation, and to Mr Niccolo Mosesso for discussing the TEM protocol improvement. This research was supported by the Bridging Stipend of University of Konstanz (No.638/20, granted to NY), the DFG Research Grant (No. YA 577/2-1, granted to NY), and the Symbiosis Model Systems Award (No. GBMF9360, granted to NY, RT, DGM, PGK) of the Gordon and Betty Moore Foundation. The CERCA Programme of Generalitat of Catalonia is also acknowledged. The Royal Botanic Garden Edinburgh is supported by the Scottish Government’s Rural and Environment Science and Analytical Services Division.info:eu-repo/semantics/publishedVersio
Multisignal control of expression of the LHCX protein family in the marine diatom Phaeodactylum tricornutum
Diatoms are phytoplanktonic organisms that grow successfully in the ocean where light conditions are highly variable. Studies of the molecular mechanisms of light acclimation in the marine diatom Phaeodactylum tricornutum show that carotenoid de-epoxidation enzymes and LHCX1, a member of the light-harvesting protein family, both contribute to dissipate excess light energy through non-photochemical quenching (NPQ). In this study, we investigate the role of the other members of the LHCX family in diatom stress responses. Our analysis of available genomic data shows that the presence of multiple LHCX genes is a conserved feature of diatom species living in different ecological niches. Moreover, an analysis of the levels of four P. tricornutum LHCX transcripts in relation to protein expression and photosynthetic activity indicates that LHCXs are differentially regulated under different light intensities and nutrient starvation, mostly modulating NPQ capacity. We conclude that multiple abiotic stress signals converge to regulate the LHCX content of cells, providing a way to fine-tune light harvesting and photoprotection. Moreover, our data indicate that the expansion of the LHCX gene family reflects functional diversification of its members which could benefit cells responding to highly variable ocean environments
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