Impact of the 3D source geometry on time-delay measurements of lensed type-Ia Supernovae

It has recently been proposed that gravitationally lensed type-Ia supernovae can provide microlensing-free time-delay measurements provided that the measurement is taken during the achromatic expansion phase of the explosion and that color light curves are used rather than single-band light curves. If verified, this would provide both precise and accurate time-delay measurements, making lensed type-Ia supernovae a new golden standard for time-delay cosmography. However, the 3D geometry of the expanding shell can introduce an additional bias that has not yet been fully explored. In this work, we present and discuss the impact of this effect on time-delay cosmography with lensed supernovae and find that on average it leads to a bias of a few tenths of a day for individual lensed systems. This is negligible in view of the cosmological time delays predicted for typical lensed type-Ia supernovae but not for the specific case of the recently discovered type-Ia supernova iPTF16geu, whose time delays are expected to be smaller than a day.Comment: 7 pages, 4 figures, published in A&

Modélisation de l'évolution du couvert nival, sur le sous-bassin LG4 de la rivière La Grande dans le nord du Québec, à l'aide du modèle français CROCUS

Au Québec, l'accumulation de la neige au sol prend une grande importance dans bon nombre d'activités humaines comme la production d'hydroélectricité. Face à cette importance de la neige, il devient fort intéressant de faire appel à des outils de modélisation dans le but de faire le suivi complet du manteau neigeux par la simulation des différents processus physiques agissant sur le couvert nival. En ce sens, la présente recherche vise à évaluer la capacité d'adaptation aux conditions environnementales du Québec, du modèle français multicouches CROCUS de suivi et de fonte du couvert nival, en vue de son utilisation ultérieure. Le choix du site d'étude s'accorde avec la présence de stations d'acquisition de données sur le couvert nival et la disponibilité d'un large éventail de données météorologiques essentielles aux modélisations.Suite au prétraitement des données d'entrée, le modèle CROCUS a pu être étalonné dans le but d'évaluer ses aptitudes à simuler l'évolution de l'épaisseur et de l'équivalent en eau du couvert nival, de même que les profils de densité et de température de ce couvert. Compte tenu des données disponibles, les résultats des périodes d'étalonnage et de vérification peuvent être considérés comme très bons et très encourageants pour des applications ultérieures de CROCUS au Québec.In Québec, snow accumulation on the ground is important for a large number of activities, including hydroelectric production. Snow being an important environmental aspect to look at for operations in cold regions, making use of adequate models able to simulate the various physical processes affecting the characteristics of the snowpack throughout the entire snow season becomes also quite important. So, the present project aims to evaluate the ability of the CROCUS French multilayer snow model to be adapted to Northern Quebec environmental conditions. The choice of the study area has been done on the basis of data availability on both the temporal evolution the snowpack at three automatic stations and the meteorological variables necessary as input to the model. Following preprocessing of input data, the CROCUS model has been calibrated in order to evaluate his capability to simulate the temporal evolution not only of the thickness and water equivalent of the snowpack, but also of the density and temperature profiles within the pack. Given the available data, the results for both the calibration and verification periods can be considered as good and very encouraging for future applications of the CROCUS model in Québec

Etudes epidemiologiques sur la rouille de l'arachide en Cote d'Ivoire

The study of the pathosystem: Arachis hypogaea - Puccinia arachidis was undertaken at different scales: the leaf, the plant, the field, the region, which allow to consider the monocyclic (leaf and plant) and polycyclic (field and region) processes. Several epidemiological processes were investigated as well as their succession during the epidemic build-up. At the region scale, some other important diseases of groundnut were considered, leading to a study of the multiple pathosystem: Arachis hypogaea - Puccinia arachidis - Cercosporidium personatum - Cercospora arachidicola .A preliminary analysis of the data from a survey in the various regions of Ivory Coast where groundnut is cultivated showed that rust was omnipresent. A correspondence analysis allowed to unravel the large variations of weather, cropping, and pathological situations, and to produce a general picture of the development of an average small farmer's field in time. Every year, general epidemics of groundnut rust developped in the Northern and Central regions. These were, to a large extent, ascribed to the endemicity of groundnut rust in the Southern region, which is a permanent source of inoculum.Several inoculation methods of detached leaf lets with groundnut rust were compared under laboratory conditions. The infection efficiency is highest with dry urediniospores at low inoculum level and lowest with suspended urediniospores at high inoculum level.The effects of temperature and inoculum level on the monocyclic process were investigated. Temperatures of about 27°C appeared to be optimal for rust development: infection efficiency, infectious period, and sporulation intensity were then highest, while latency period was lowest. Temperature effects on groundnut rust were compared to those on other host-rust systems, The results suggested that temperature variation has a strong effect on the development of groundnut rust epidemics.Leaf age and plant development stage were also considered as influencing factors on rust development on a susceptible groundnut cultivar. The results, a reduction of infection efficiency with increasing leaf age and an increase of latency period with increasing leaf age and development stage, indicated that different leaf layers in the canopy could differ in their epidemiological parameters.The monocyclic studies on detached leaflets were accompanied by experiments on potted plants, which yielded the same general conclusions on the effects of some factors. Differences in values of variables were found (for the infection efficiency and latency period), which were discussed.Aerial dispersal of dry spores was studied In artificial groundnut rust foci. A significant linear regression was found of the logit of the relative spore content of the air on the logit of rust intensity expressed as the number of lesions m -2of field. A major explanatory variable of the diurnal rhythmicity of the aerial spore density was relative humidity, and a secondary one was wind velocity. The hypothesis was put forward that these variables affect rhythmicity over the whole range of variation of the aerial spore density as measured at different rust intensities.Rain-induced dispersal of groundnut rust urediniospores was studied in artificially infected plots on which variable rainfall amounts and intensities were applied, using a rainfall simulator. Several trapping methods allowed to compare dry, splash and drip dispersal. The spore liberation mechanisms and the resulting spore flows were considered at the canopy and at the individual lesion scales. The results indicated that dry dispersal was predominant. The observed increase of the flow of spores dripping from the canopy to the soil with increasing rainfall amounts suggested that light rain showers were favourable, whereas heavy showers were unfavourable to rust dispersal.Disease dispersal from artificial foci was studied with respect of variation in canopy structure with increasing plot age, The primary gradients of rust which developped in older plots had higher mean values and slopes. The relative height of infection was also higher in older plots. These age-dependant variations were attributed to variations in dispersibility and accessibility. The results also indicated a strong ability of groundnut rust to disperse at mesoscaleThe analysis of survey data was resumed, focusing on groundnut rust epidemiology. This disease exhibited marked weather (temperature and rainfall) requirements, strong dispersal abilities at mesoscale and macroscale, and intensified quickly in well-tended crops. These characteristics differed much from those of leaf-spot diseases, especially C. arachidicola leaf-spot. The conclusions of this analysis were in agreement with previous results from monocyclic experiments, The hypothesis is forwarded that intensification in groundnut cultivation would enhance rust epidemics build-up,The results of this thesis on groundnut rust epidemiology may be assembled to build a pictorial, qualitative model or a quantitative summary model for dynamic simulation. Both approaches allow to identify gaps in the available information and to evaluate the results of these studies

Hydrological responses of a watershed to historical land use evolution and future land use scenarios under climate change conditions

Watershed runoff is closely related to land use but this influence is difficult to quantify. This study focused on the Chaudière River watershed (Québec, Canada) and had two objectives: (i) to quantify the influence of historical agricultural land use evolution on watershed runoff; and (ii) to assess the effect of future land use evolution scenarios under climate change conditions (CC). To achieve this, we used the integrated modeling system GIBSI. Past land use evolution was constructed using satellite images that were integrated into GIBSI. The general trend was an increase of agricultural land in the 80's, a slight decrease in the beginning of the 90's and a steady state over the last ten years. Simulations showed strong correlations between land use evolution and water discharge at the watershed outlet. For the prospective approach, we first assessed the effect of CC and then defined two opposite land use evolution scenarios for the horizon 2025 based on two different trends: agriculture intensification and sustainable development. Simulations led to a wide range of results depending on the climatologic models and gas emission scenarios considered, varying from a decrease to an increase of annual and monthly water discharge. In this context, the two land use scenarios induced opposite effects on water discharge and low flow sequences, especially during the growing season. However, due to the large uncertainty linked to CC simulations, it is difficult to conclude that one land use scenario provides a better adaptation to CC than another. Nevertheless, this study shows that land use is a key factor that has to be taken into account when predicting potential future hydrological responses of a watershed

Optimization of the Even Normal Multipole Components in the Main Dipole of the Large Hadron Collider

In this paper we discuss even multipolar components of the Large Hadron Collider dipole in relation to the manufacturing features and target values required by beam dynamics. Due to the two-in-one collar geometry, systematic components are induced by the mutual influence of the two apertures and are strongly affected by the shape of the magnetic iron yoke. In order to optimize the normal quadrupole and octupole harmonics, a new design was chosen for the ferromagnetic insert between the iron yoke and the collars. Three different insert shapes were selected and installed in a full scale prototype. The measured dependence of the even multipoles on the insert shape shows a good agreement with simulations based on a magnetostatic code. A final design of the insert has been worked out and implemented in pre-series magnets. Data relative to even multipoles in pre-series magnets are presented, both at room temperature and at the operational temperature of 1.9 K. Comparison with target values required by beam dynamics is discussed

PARSEME Survey on MWE Resources

International audienceThis paper summarizes the first results of an ongoing survey on multiword resources carried out within the IC1207 Cost ActionPARSEME (PARSing and Multi-word Expressions). Despite the availability of language resource catalogues and the inventory ofmultiword data-sets available at the SIGLEX-MWE website, multiword resources are scattered and prove to be difficult to be found.In many cases, language resources such as corpora, treebanks or lexical databases include multiwords as part of their data or take theminto consideration in their annotations. However, it is needed to centralize these resources so that other researches may subsequentlyuse them. The final aim of this survey is thus to create a portal where researchers may find multiword resources or multiword-awarelanguage resources for their research. We report on how the survey was designed and analyze the data gathered so far. We also discussthe problems we have detected upon examination of the data and possible ways of enhancing the survey

People making deontological judgments in the Trapdoor dilemma are perceived to be more prosocial in economic games than they actually are

Why do people make deontological decisions, although they often lead to overall unfavorable outcomes? One account is receiving considerable attention: deontological judgments may signal commitment to prosociality and thus may increase people’s chances of being selected as social partners–which carries obvious long-term benefits. Here we test this framework by experimentally exploring whether people making deontological judgments are expected to be more prosocial than those making consequentialist judgments and whether they are actually so. In line with previous studies, we identified deontological choices using the Trapdoor dilemma. Using economic games, we take two measures of general prosociality towards strangers: trustworthiness and altruism. Our results procure converging evidence for a perception gap according to which Trapdoor-deontologists are believed to be more trustworthy and more altruistic towards strangers than Trapdoor-consequentialists, but actually they are not so. These results show that deontological judgments are not universal, reliable signals of prosociality

Stocking activities for the Arctic charr in Lake Geneva: Genetic effects in space and time

Artificial stocking practices are widely used by resource managers worldwide, in order to sustain fish populations exploited by both recreational and commercial activities, but their benefits are controversial. Former practices involved exotic strains, although current programs rather consider artificial breeding of local fishes (supportive breeding). Understanding the complex genetic effects of these management strategies is an importan t challenge with economic and conservation implications, especially in the context of population declines. In this study, we focus on the declining Arctic charr (Salvelinus alpinus) population from Lake Geneva (Switzerland and France), which has initially been restocked with allochtonous fishes in the early eighties, followed by supportive breeding. In this context, we conducted a genetic survey to document the evolution of the genetic diversity and structure throughout the last 50 years, before and after the initiation of hatchery supplementation, using contemporary and historical samples. We show that the introduction of exotic fishes was associated with a genetic bottleneck in the 1980–1990s, a break of Hardy–Weinberg Equilibrium (HWE), a reduction in genetic diversity, an increase in genetic structure among spawning sites, and a change in their genetic composition. Together with better environmental conditions, three decades of subsequent supportive breeding using local fishes allowed to re-establish HWE and the initial levels of genetic variation. However, current spawning sites have not fully recovered their original genetic composition and were extensively h omogenized across the lake. Our study demonstrates the drastic genetic consequ e nces of different restocking tactics in a comprehensive spatiotemporal framewo rk and suggests that genetic alteration by nonlocal stocking may be partly reversible through supportive breeding. We recommend that conservation-based programs consider local diversity and implement adequate protocols to limit the genetic homogenization of this Arctic charr population

HOLISMOKES -- II. Identifying galaxy-scale strong gravitational lenses in Pan-STARRS using convolutional neural networks

We present a systematic search for wide-separation (Einstein radius >1.5"), galaxy-scale strong lenses in the 30 000 sq.deg of the Pan-STARRS 3pi survey on the Northern sky. With long time delays of a few days to weeks, such systems are particularly well suited for catching strongly lensed supernovae with spatially-resolved multiple images and open new perspectives on early-phase supernova spectroscopy and cosmography. We produce a set of realistic simulations by painting lensed COSMOS sources on Pan-STARRS image cutouts of lens luminous red galaxies with known redshift and velocity dispersion from SDSS. First of all, we compute the photometry of mock lenses in gri bands and apply a simple catalog-level neural network to identify a sample of 1050207 galaxies with similar colors and magnitudes as the mocks. Secondly, we train a convolutional neural network (CNN) on Pan-STARRS gri image cutouts to classify this sample and obtain sets of 105760 and 12382 lens candidates with scores pCNN>0.5 and >0.9, respectively. Extensive tests show that CNN performances rely heavily on the design of lens simulations and choice of negative examples for training, but little on the network architecture. Finally, we visually inspect all galaxies with pCNN>0.9 to assemble a final set of 330 high-quality newly-discovered lens candidates while recovering 23 published systems. For a subset, SDSS spectroscopy on the lens central regions proves our method correctly identifies lens LRGs at z~0.1-0.7. Five spectra also show robust signatures of high-redshift background sources and Pan-STARRS imaging confirms one of them as a quadruply-imaged red source at z_s = 1.185 strongly lensed by a foreground LRG at z_d = 0.3155. In the future, we expect that the efficient and automated two-step classification method presented in this paper will be applicable to the deeper gri stacks from the LSST with minor adjustments.Comment: 18 pages and 11 figures (plus appendix), submitted to A&