Crossover from spin accumulation into interface states to spin injection in the germanium conduction band

Electrical spin injection into semiconductors paves the way for exploring new phenomena in the area of spin physics and new generations of spintronic devices. However the exact role of interface states in spin injection mechanism from a magnetic tunnel junction into a semiconductor is still under debate. In this letter, we demonstrate a clear transition from spin accumulation into interface states to spin injection in the conduction band of $n$-Ge. We observe spin signal amplification at low temperature due to spin accumulation into interface states followed by a clear transition towards spin injection in the conduction band from 200 K up to room temperature. In this regime, the spin signal is reduced down to a value compatible with spin diffusion model. More interestingly, we demonstrate in this regime a significant modulation of the spin signal by spin pumping generated by ferromagnetic resonance and also by applying a back-gate voltage which are clear manifestations of spin current and accumulation in the germanium conduction band.Comment: 5 pages, 4 figure

Assessment of the phenology impact on SVAT modelling through a crop growth model over a Mediterranean crop site : Consequences on the water balance under climate change conditions.

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Assessing the potentialities of FORMOSAT-2 data for water and crop monitoring at small regional scale in South-Eastern France

International audienceWater monitoring at the scale of a small agricultural region is a key point to insure a good crop development particularly in South-Eastern France, where extreme climatic conditions result in long dry periods in spring and summer with very sparse precipitation events, corresponding to a crucial period of crop development. Remote sensing with the increasing imagery resolution is a useful tool to provide information on plant water status over various temporal and spatial scales. The current study focussed on assessing the potentialities of FORMOSAT-2 data, characterized by high spatial (8m pixel) and temporal resolutions (1-3 day/time revisit), to improve crop modeling and spatial estimation of the main land properties. Thirty cloud free images were acquired from March to October 2006 over a small region called Crau-Camargue in SE France, while numerous ground measurements were performed simultaneously over various crop types. We have compared two models simulating energy transfers between soil, vegetation and atmosphere: SEBAL and PBLs. Maps of evapotranspiration were analyzed according to the agricultural practices at field scale. These practices were well identified from FORMOSAT-2 images, which provided accurate input surface parameters to the SVAT models

Assessment of the phenology impact on SVAT modelling through a crop growth model under climate change conditions and consequences on the water balance.

International audienc

Assessment of the phenology impact on SVAT modelling through a crop growth model under climate change conditions and consequences on the water balance.

International audienc

Multi-year assessment of soil-vegetation-atmosphere transfer (SVAT) modeling uncertainties over a Mediterranean agricultural site.

International audienc

Multi- year assessment of surface vegetation atmosphere transfer (SVAT) modeling uncertainties over Mediterranean Agricicultural site.

International audienc

Structural characterization of IrisFP, an optical highlighter undergoing multiple photo-induced transformations

Photoactivatable fluorescent proteins (FPs) are powerful fluorescent highlighters in live cell imaging and offer perspectives for optical nanoscopy and the development of biophotonic devices. Two types of photoactivation are currently being distinguished, reversible photoswitching between fluorescent and nonfluorescent forms and irreversible photoconversion. Here, we have combined crystallography and (in crystallo) spectroscopy to characterize the Phe-173-Ser mutant of the tetrameric variant of EosFP, named IrisFP, which incorporates both types of phototransformations. In its green fluorescent state, IrisFP displays reversible photoswitching, which involves cis–trans isomerization of the chromophore. Like its parent protein EosFP, IrisFP also photoconverts irreversibly to a red-emitting state under violet light because of an extension of the conjugated ?-electron system of the chromophore, accompanied by a cleavage of the polypeptide backbone. The red form of IrisFP exhibits a second reversible photoswitching process, which may also involve cis–trans isomerization of the chromophore. Therefore, IrisFP displays altogether 3 distinct photoactivation processes. The possibility to engineer and precisely control multiple phototransformations in photoactivatable FPs offers exciting perspectives for the extension of the fluorescent protein toolkit

Transferts hydriques aquifère-sol-végétation-atmosphère.

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