Knocking on heaven's door : are novel invaders necessarily facing naive native species on islands ?

The impact of alien predator species on insular native biota has often been attributed to island prey naivete (i.e. lack of, or inefficient, anti-predator behavior). Only rarely, however, has the concept of island prey naivete been tested, and then only a posteriori (i.e. hundreds or thousands of years after alien species introduction). The presence of native or anciently introduced predators or competitors may be crucial for the recognition and development of adaptive behavior toward unknown predators or competitors of the same archetype (i.e. a set of species that occupy a similar ecological niche and show similar morphological and behavioral traits when interacting with other species). Here, we tested whether two squamates endemic to New Caledonia, a skink, Caledoniscincus austrocaledonicus, and a gecko, Bavayia septuiclavis, recognized and responded to the odor of two major invaders introduced into the Pacific islands, but not yet into New Caledonia. We chose one predator, the small Indian mongoose Herpestes javanicus and one competitor, the cane toad Rhinella marina, which belong respectively to the same archetype as the following two species already introduced into New Caledonia in the nineteenth century: the feral cat Felis catus and the golden bell frog Litoria aurea. Our experiment reveals that geckos are naive with respect to the odors of both an unknown predator and an unknown competitor, as well as to the odors of a predator and a competitor they have lived with for centuries. In contrast, skinks seem to have lost some naivete regarding the odor of a predator they have lived with for centuries and seem "predisposed" to avoid the odor of an unknown potential competitor. These results indicate that insular species living in contact with invasive alien species for centuries may be, although not systematically, predisposed toward developing adaptive behavior with respect to species belonging to the same archetype and introduced into their native range

Optimization of DC reactive magnetron sputtering deposition process for efficient YSZ electrolyte thin film SOFC

International audienceYttria-stabilized zirconia (YSZ, ZrO2:Y2O3) thin films were deposited by reactive DC magnetron sputtering with a high deposition rate from a metallic target of Zr/Y in an argon/oxygen atmosphere. Plasma parameters and composition analysis of the gas phase reveal that the sputtering process in the "compound" mode is reached for a 2.5 sccm oxygen flow rate. Deposition onto silicon in "metal" mode at a flow rate close to the transition, allows obtaining at very high deposition rates (> 10 µm.h-1) a compact columnar stoichiometric crystallized YSZ film. When deposited on NiO YSZ commercial anode, the obtained coatings show the same properties. In spite of the complexity of the substrate (roughness and porosity), a compact and conformed layer was formed. Annealing treatments in air or hydrogen do not significantly alter the structure of the layers. Electrochemical test at 850°C with a screen-printed LSM (LaSrMnO3) cathode exhibits a satisfying gastightness (OCV=900 mV) and a maximum power density of 350 mW.cm-2

Realization of Conductive Wells for Rear Side Electrical Contact of Integrated Solar Cell

AbstractThe so-called integrated solar cell (i-Cell) consists of several small area sub-cells manufactured by bonding monocrystalline Si (mono-Si) thin foils (20-60μm) ontocost effective insulating substrates on which local conductive wells have been previously integrated. In this paper, we report on the realization of deep recrystallized conductive wells acting as the rear side electrical contact of each sub-cell. These conductive wells have been produced by screen-printing of a thick aluminum (Al) layer followed by a fast-firing process for the formation of the back electrode of each sub-cell. The i-Cell delivers a high voltage and a low current, which reduces the resistive losses in the interconnections of i-cells and modules. The influence of firing temperature profile on the depths and electrical properties of conductive wells are investigated. The feasibility of i-Cell realized on these deep recrystallized conductive wells has been demonstrated. The preliminary results, obtained from 156x156 mm2 i-Cell on which four sub-cells are connected in series, show an efficiency over 16%, with a short circuit current of 2.1 A and an open circuit voltage of 2.5V

Ernst Freund as Precursor of the Rational Study of Corporate Law

Gindis, David, Ernst Freund as Precursor of the Rational Study of Corporate Law (October 27, 2017). Journal of Institutional Economics, Forthcoming. Available at SSRN: https://ssrn.com/abstract=2905547, doi: https://dx.doi.org/10.2139/ssrn.2905547The rise of large business corporations in the late 19th century compelled many American observers to admit that the nature of the corporation had yet to be understood. Published in this context, Ernst Freund's little-known The Legal Nature of Corporations (1897) was an original attempt to come to terms with a new legal and economic reality. But it can also be described, to paraphrase Oliver Wendell Holmes, as the earliest example of the rational study of corporate law. The paper shows that Freund had the intuitions of an institutional economist, and engaged in what today would be called comparative institutional analysis. Remarkably, his argument that the corporate form secures property against insider defection and against outsiders anticipated recent work on entity shielding and capital lock-in, and can be read as an early contribution to what today would be called the theory of the firm.Peer reviewe

The impact of human expert visual inspection on the discovery of strong gravitational lenses

We investigate the ability of human ’expert’ classifiers to identify strong gravitational lens candidates in Dark Energy Survey like imaging. We recruited a total of 55 people that completed more than 25% of the project. During the classification task, we present to the participants 1489 images. The sample contains a variety of data including lens simulations, real lenses, non-lens examples, and unlabeled data. We find that experts are extremely good at finding bright, well-resolved Einstein rings, whilst arcs with g-band signal-to-noise less than ∼25 or Einstein radii less than ∼1.2 times the seeing are rarely recovered. Very few non-lenses are scored highly. There is substantial variation in the performance of individual classifiers, but they do not appear to depend on the classifier’s experience, confidence or academic position. These variations can be mitigated with a team of 6 or more independent classifiers. Our results give confidence that humans are a reliable pruning step for lens candidates, providing pure and quantifiably complete samples for follow-up studies

Correction to: Cluster identification, selection, and description in Cluster randomized crossover trials: the PREP-IT trials

An amendment to this paper has been published and can be accessed via the original article

Croissance par ablation laser de films minces d'oxyde pour la réalisation de structures optiquement guidantes

Notre démarche générale s'inscrit dans la réalisation de structures optiquement guidantes sous forme de films minces pour des applications en optoélectronique intégrée. Le matériau choisi pour la réalisation de couches minces optiquement actives est le titanate de plomb PbTiO3 (PT). En effet, ses coefficients optiques non linéaires en font un excellent candidat pour la génération d'un faisceau laser bleu par doublage de fréquence d'une diode laser émettant à 980 nm. Si la génération de second harmonique est connue et assez bien maîtrisée dans les cristaux massifs, la transposition de ce principe aux matériaux en couches minces reste délicate à mettre en œuvre. Dans ce travail, les couches minces de titanate de plomb sont réalisées par ablation laser (ou pulsed-laser deposition : PLD). L'optimisation des conditions de croissance a permis d'obtenir des films minces orientés et épitaxiés d'excellente qualité morpho-stucturale sur substrat monocristallin de MgO (100). Leurs propriétés de guides d'onde étudiées par spectroscopie des lignes noires (m-lines) montrent que les caractéristiques optiques des films minces de PT sont identiques à celles du matériau massif. Les pertes optiques mesurées à 633 nm sont inférieures à 1 dB/cm, valeur qui constitue le meilleur résultat obtenu jusqu'à présent sur de tels systèmes (PbTiO3/Substrat). La perspective de réaliser des structures optiquement guidantes capables de générer un laser bleu par quasi accord de phase dans un dispositif intégré PT/MgO/Si pourrait s'envisager mais cela nécessite la réalisation du retournement périodique des domaines ferroélectriques avec une résolution que la technologie actuelle ne permet d'accéder.Our general thought process (démarche de la pensée) is in keeping with the general pattern of the realization of optical waveguiding thin films for integrated optoelectronic applications. The matérial of choice is lead titanate PbTiO3 (PT). This compound is widely studied and well known for its ferroelectric properties, but it has not been used yet in optical devices for which the reference material is lithium niobate LiNbO3. Nevertheless, the non linear optical coefficients of PT are promising for the generation of a blue light source from laser diodes which emit at 980 nm. If the second harmonic generation is well known and mastered for bulk materials, the transposition in thin films is still difficult. In this study, lead titanate thin films were grown by pulsed-laser deposition (PLD). The growth conditions on (100)MgO substrate were optimized such as substrate temperature, oxygen pressure ou laser fluence to grow oriented and epitaxial thin films with excellent structural properties and surface roughness. The waguiding properties studied by m-lines spectroscopy indicate that optical characteritics (refractive indices) of thin films are the same as the bulk's ones. The optical losses measured at 632,8 nm are lower than 1 dB/cm, which constitute the best results obtained up to now on this kind of system (PbTiO3/Substrate). Future prospects for the realization of optical waguiding structures for the generation of blue light by quasi phase matching (QPM) in integrated devices PT/MgO/Si could be considered but it requires the realization of periodic poled thin films with a resolution that actual technology couldn't realize at this time.METZ-SCD (574632105) / SudocSudocFranceF

Croissance par ablation laser pulsé de nouvelles phases d'oxyde de titane pour l'électronique transparente et la conversion de photons

Le photovoltaïque nécessite de nouveaux matériaux pour diminuer ces coûts et améliorer les rendements. Ces travaux de thèse ont concerné le développement de nouvelles phases d'oxyde de titane pour l'électronique transparente et la conversion de photon appliquée au PV silicium. L'ablation laser pulsé est une méthode de croissance particulièrement adaptée pour la prospection de matériaux aux propriétés innovantes. Le contrôle des phases anatase, rutile et d'une phase de composition TiO1.45 épitaxié en fonction de la pression partielle d'oxygène a permis de réaliser des films aux propriétés électriques, optiques innovantes. Un film biphasé anatase/rutile dopé niobium (TNO1.80) présente ainsi une transition métal-semi-conducteur aux alentours de 68K. Par ailleurs, le film de composition TiO1.45 épitaxié s'est révélé être un oxyde transparent conducteur de type p. La découverte de ce nouveau p-TCOs a été valorisée et validée par l'élaboration d'une homojonction p - n transparente. Les matrices d'oxyde de titane rutile et anatase ont également été utilisées pour accueillir des ions terres rares Ln3+ afin de convertir les photons ultra-violet du spectre solaire incident vers le proche infrarouge (800 > > 1100 nm). Le transfert d'énergie des matrices TiO2 vers les dopants Ln3+ a été étudié en fonction de la structure, de la quantité de dopant ainsi que la qualité de la microstructure des films dopés Ln3+ (Ln3+=Pr3+,Tm3+,Eu3+,Yb3+,Nd3+).New materials are needed to decrease cost and improve photovoltaic cell performance. These thesis works are focused on the development of new titanium oxide phases for transparent electronic and photon conversion applied to silicon solar cell. Pulsed laser deposition is an adapted growth method for the prospection of materials with innovating properties. The control of epitaxial growth of anatase, rutile and a phase with a composition TiO1.45 in function of oxygen partial pressure allowed us to realize films with innovating electrical and optical properties. A two phase anatase/rutile film doped niobium (TNO1.80) have shown a metal-semiconductor transition about 68 K. Moreover, transparent TiO1.45 epitaxial thin film has displayed a p-type semiconduction behaviour which has been confirmed by the elaboration of a transparent p - n homojunction. Rutile and anatase titanium oxide matrix were also used to host rare earths ions in order to convert ultraviolet to near infra-red photon (800 > > 1100 nm). TiO2 matrix to dopant transfer has been studied in function of crystal structure, doping content and the quality of microstructure of films doped Ln3+(Ln3+=Pr3+,Tm3+,Eu3+,Yb3+,Nd3+).ORLEANS-SCD-Bib. electronique (452349901) / SudocSudocFranceF