Nitrogen deficiency increases basal branching and modifies visual quality of the rose bushes

Rosebush architecture resulting from the spatial organisation of the plant axes induces plant shape and consequently within ornamental horticulture context, its visual quality and commercial value. This architecture can be modulated by environmental conditions, particularly in the horticulture context in which the possibilities to control growing conditions are numerous. The objectives of the study were to determine, in young rose bushes, (1) whether short periods of nitrogen deficiency affect branching and (2) whether this effect is sufficient to modify the visual quality of the plant in a sustainable manner. Between vegetative bud burst and the petal colour visible stage of the generated primary branch, young rooted cuttings of bush rose (cv Radrazz) were subjected to one of three nitrogen regimes: (1) no nitrogen deficiency, (2) continuous nitrogen deficiency, i.e. 35 days of N deficiency, and (3) nitrogen deficiency restricted to the flowering stages, i.e. 18 days of N deficiency. After the petal colour visible stage, all three groups of plants were supplied continuously with nitrogen. We observed the morphology of the axes and the kinetics of axillary bud burst. Twelve weeks after the petal colour visible stage, the visual quality of the rose bushes was evaluated by an expert jury. We found that nitrogen deficiencies (1) increased bud burst ratios in the medial and basal zones of the primary branch, (2) delayed the bud burst in the apical zone of the primary branch and (3) had long-term effects on plant visual quality. The continuous nitrogen deficiency regime produced flatter, more asymmetric and less vigorous rose bushes than the no nitrogen deficiency regime. By contrast, nitrogen deficiency during the flowering stages only resulted in more symmetric, taller and more vigorous rose bushes than the no nitrogen deficiency regime. Based on these results, the role of nitrogen on bud burst was discussed and candidate processes at the origin of the visual quality modification were suggested. This new approach combining ecophysiology and sensory assessment of ornamental plants enabled the identification of some early architecture components to be correlated with later visual quality characteristics and then to better target the physiological processes of interest

Blue light effects on rose photosynthesis and photomorphogenesis

Through its impact on photosynthesis and morphogenesis, light is the environmental factor that most affects plant architecture. Using light rather than chemicals to manage plant architecture could reduce the impact on the environment. However, the understanding of how light modulates plant architecture is still poor and further research is needed. To address this question, we examined the development of two rose cultivars, Rosa hybrida‘Radrazz’ and Rosa chinensis‘Old Blush’, cultivated under two light qualities. Plants were grown from one-node cuttings for 6 weeks under white or blue light at equal photosynthetic efficiencies. While plant development was totally inhibited in darkness, blue light could sustain full development from bud burst until flowering. Blue light reduced the net CO2 assimilation rate of fully expanded leaves in both cultivars, despite increasing stomatal conductance and intercellular CO2 concentrations. In ‘Radrazz’, the reduction in CO2 assimilation under blue light was related to a decrease in photosynthetic pigment content, while in both cultivars, the chl a/b ratio increased. Surprisingly, blue light could induce the same organogenetic activity of the shoot apical meristem, growth of the metamers and flower development as white light. The normal development of rose plants under blue light reveals the strong adaptive properties of rose plants to their light environment. It also indicates that photomorphogenetic processes can all be triggered by blue wavelengths and that despite a lower assimilation rate, blue light can provide sufficient energy via photosynthesis to sustain normal growth and development in roses

Thromboembolic risk stratification by TRiP(cast) score to rationalise thromboprophylaxis in patients with lower leg trauma requiring immobilisation: a study protocol of the casting stepped-wedge cluster randomised trial.

Patients with lower limb trauma requiring orthopaedic immobilisation may be at risk of venous thromboembolism but opinions differ about who may benefit from thromboprophylactic anticoagulant treatment.The aim of this CASTING study is to demonstrate the safety of thromboprophylaxis based on the Thrombosis Risk Prediction for patients with cast immobilisation (TRiP(cast) score with regards to the 3-month incidence of symptomatic venous thromboembolism events in low-risk patients not receiving thromboprophylaxis, as well as the usefulness of this strategy on the rate of patients receiving anticoagulant treatment in comparison to current practice. CASTING will be a stepped-wedge cluster randomised controlled clinical trial, performed in 15 emergency departments in France and Belgium. With their informed consent, outpatients admitted to one of the participating emergency departments for a lower limb trauma requiring orthopaedic immobilisation without surgery will be included. All centres will begin the trial with the 'observational period' and, every 2 weeks, 1 centre will be randomly assigned to switch to the 'interventional period' and to apply the TRiP(cast) score, in which only patients with a score ≥7 will receive thromboprophylactic anticoagulant treatment. The primary endpoint is the rate of clinical thromboembolic events within 90 days following the inclusion of low-risk patients not receiving thromboprophylaxis. The protocol has been approved by the Comité de Protection des Personnes Sud I (Ethics Review ID-RCB: 2019-A01829-48) for France and the Comité d'éthique hôpital-facultaire Saint Luc (N° B403201941338) for Belgium. It is carried out in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines. The findings of this study will be disseminated in peer-reviewed journals and at scientific conferences. NCT04064489

French political science at a turning point

This paper outlines the origins and institutionalization process of French political science since 1945. It sketches the present state of the discipline, and it analyses recent trends that appear almost as a form of ‘de-institutionalization’. Overall, the discipline is quite well entrenched and is independent in terms of recruitment with its own teaching and research branches. However, political scientists suffer from a relative lack of visibility in the public space in comparison with their colleagues from more prominent disciplines. In many fields French political science remains invisible at the international level, though this may change considerably in the years to come. The main element of uncertainty comes from the ongoing reforms, the redefinition of the partnership between universities, the Instituts d'Etudes Politiques and the CNRS, and the way the autonomy of universities will be implemented

Development of a PbWO4 Detector for Single-Shot Positron Annihilation Lifetime Spectroscopy at the GBAR Experiment

We have developed a PbWO4 (PWO) detector with a large dynamic range to measure the intensity of a positron beam and the absolute density of the ortho-positronium (o-Ps) cloud it creates. A simulation study shows that a setup based on such detectors may be used to determine the angular distribution of the emission and reflection of o-Ps to reduce part of the uncertainties of the measurement. These will allow to improve the precision in the measurement of the cross-section for the (anti)hydrogen formation by (anti)proton-positronium charge exchange and to optimize the yield of antihydrogen ion which is an essential parameter in the GBAR experiment

Origine, transport et devenir des apports naturels et anthropiques dans le lagon sud-ouest de Nouvelle-Calédonie

L’ird (Institut de recherche pour le développement) conduit depuis dix ans un programme pluridisciplinaire sur les effets des apports naturels et anthropiques sur le fonctionnement du lagon de Nouvelle-Calédonie. Celle-ci connaît actuellement une croissance de sa population et un développement de son industrie minière. Trois grands types d’apports sont pris en compte : les particules entraînées par l’érosion des sols et des sous-sols et dont l'accumulation brutale peut être responsable du dépôt de quantités considérables de sédiments, les métaux potentiellement toxiques pour les organismes vivant dans le lagon et les éléments nutritifs susceptibles de conduire les eaux jusqu'à l’eutrophisation (confinement chimique conduisant à l'élimination de nombreuses espèces vivantes et à la dominance d'un petit nombre d'autres). Le présent article offre trois exemples de problématiques environnementales qui n'ont pu être résolues qu’au moyen de la fédération de différentes approches de recherche complémentaires : l’influence des courants sur la dispersion des particules détritiques en provenance de l'île, le devenir des métaux dans le lagon et leur accumulation dans les organismes, les effets des apports en nutriments sur les communautés planctoniques et les risques d'eutrophisation. Les résultats de ces recherches sont présentés tout en conservant à l’esprit les objectifs nécessairement appliqués d’un programme de recherche pour le développement. Il s’agit principalement de définir les bases scientifiques permettant d’identifier certains outils de diagnostic environnemental et de développer des approches de simulation mathématique susceptibles d'offrir une vision synthétique et prévisionnelle de l’état et du devenir des environnements lagonaires sous influence anthropique.For the past ten years, the ird (Institut de recherche pour le développement) has developed a multidisciplinary programme dealing with the effects of natural and anthropogenic terrigenous inputs on the New Caledonia coral reef lagoon which is currently subjected to environmental pressure due to population increase and development of the mining industry. The ongoing study focused on three main categories of inputs: (i) particles generated by erosion processes and responsible for excessive sediment inputs in the lagoon, (ii) metals exhibiting a potentially lethal effect on the lagoon biota, (iii) nutrients responsible for eutrophication. This article presents three examples of environmental issues that could be addressed through complementary research approaches: (i) the dispersion of terrigenous inputs as commended by currents, (ii) the fate of metals in the lagoon and their accumulation in the biota, (iii) the effects of nutrient enrichment on pelagic communities. Results are presented while keeping in mind the necessary applied outcomes requested from a research programme devoted to development issues. Such outcomes are mainly related to the identification of suited environmental diagnostic tools and to the development of modelling approaches yielding synthetic and predictive information on the status and fate of coral reef lagoons subject to anthropogenic stress

Towards a test of the weak equivalence principle of gravity using anti-hydrogen at CERN

International audienceThe aim of the GBAR (Gravitational Behavior of Antimatter at Rest) experiment is to measure the free fall acceleration of an antihydrogen atom, in the terrestrial gravitational field at CERN and therefore test the Weak Equivalence Principle with antimatter. The aim is to measure the local gravity with a 1% uncertainty which can be reduced to few parts of 10-3

Accumulation of Positrons from a LINAC Based Source

International audienc

Low exposure long-baseline neutrino oscillation sensitivity of the DUNE experiment

The Deep Underground Neutrino Experiment (DUNE) will produce world-leading neutrino oscillation measurements over the lifetime of the experiment. In this work, we explore DUNE's sensitivity to observe charge-parity violation (CPV) in the neutrino sector, and to resolve the mass ordering, for exposures of up to 100 kiloton-megawatt-years (kt-MW-yr). The analysis includes detailed uncertainties on the flux prediction, the neutrino interaction model, and detector effects. We demonstrate that DUNE will be able to unambiguously resolve the neutrino mass ordering at a 3$\sigma$ (5$\sigma$) level, with a 66 (100) kt-MW-yr far detector exposure, and has the ability to make strong statements at significantly shorter exposures depending on the true value of other oscillation parameters. We also show that DUNE has the potential to make a robust measurement of CPV at a 3$\sigma$ level with a 100 kt-MW-yr exposure for the maximally CP-violating values \delta_{\rm CP}} = \pm\pi/2. Additionally, the dependence of DUNE's sensitivity on the exposure taken in neutrino-enhanced and antineutrino-enhanced running is discussed. An equal fraction of exposure taken in each beam mode is found to be close to optimal when considered over the entire space of interest