The importance of guiding on the motion of a comet in astrometric observations

In this paper we discuss the influence of guiding on the motion of a comet on the derived astrometric position

A new method for astrometric observations of asteroids

In this paper we propose a new method for photographic astrometric observations of asteroids. We discuss its advantages and disadvantages and compare them to the advantages and disadvantages of the classical photographic methods. The new method is best suited for observations on a spot where no CCD cameras, blink or stereo comparators are available and when a fast detection of unknown objects is required

Improving port hinterland connection capacity: a comparative study of Polish and Belgian cases

The study takes a comparative approach by investigating the situation in the hinterlands of two different port areas in Europe: Antwerp (Belgium) and Gdansk-Sopot-Gdynia agglomeration (Poland). Both port centres have an important road hinterland connection that faces competition from other alternative modes of freight transport. However, the Port of Antwerp is already one of the leading ports of the continent while the ports of Gdansk and Gdynia are at the stage of building their competitive position. Also the importance of inland waterways in the transport systems in these countries is different – Belgium has a functioning network of waterways while Poland still has to develop it. The Belgian case is the E313 motorway, which makes the connection between Antwerp and Li�ge and further on also Germany. The motorway has competition from both rail and inland waterways, especially in dealing with port-bound traffic. The Albert Canal, which runs mainly in parallel with the motorway, is currently being subject to capacity expansion through the extension and elevation of a number bridges that cross the canal. Rail could specifically benefit from the potential re-activation of the Iron Rhine - an almost parallel connection to the motorway E313 between Antwerp and the German Ruhr area. The Polish case is focused on possible scenarios of freight traffic between Baltic port centre of Gdansk and Gdynia with important international harbour and fast developing regional centre - Bydgoszcz-Torun. At present the main connections between those urban areas are the state road 1, section of motorway A1 and railway CE-65. Gdansk, Torun and Bydgoszcz are also linked with Vistula river (part of international inland waterways E-40 and E-70) but so far it is not used extensively. The cases are analyzed separately. The added value of the paper is the comparative analysis which allows making conclusions that are valid for both environments. The results are of high relevance to policy makers in charge of alleviating port hinterland problems, and also to ports in the current highly competitive environment.

Construction and Validation of an Analytical Grid about Video Representations of Suicide (“MoVIES”)

International audienceExposure to fictional suicide scenes raises concerns about the risk of suicide contagion. However, researchers and clinicians still lack empirical evidence to estimate this risk. Here, we propose a theory-grounded tool that measures properties related to aberrant identification and suicidal contagion of potentially harmful suicide scenes. Methods. The items of the Movies and Video: Identification and Emotions in reaction to Suicide (MoVIES) operationalize the World Health Organization's recommendations for media coverage of suicide, and were adapted and completed with identification theory principles and cinematographic evidence. Inter-rater reliability (Cohen's kappa) and internal consistency (Cronbach's alpha) were estimated and optimized for two series of 19 and 30 randomly selected movies depicting a suicide scene. The validity of the scale in predicting identification with the suicidal character was tested in nine unknowledgeable participants who watched seven suicide movie scenes each. Results. The MoVIES indicated satisfying psychometric properties with kappas measured at 0.7 or more for every item and a global internal consistency of [α = 0.05]. The MoVIES score significantly predicted participants' strength of identification independently from their baseline empathy ((β = 0.20), p < 0.05). Conclusions. The MoVIES is available to scholars as a valid, reliable, and useful tool to estimate the amount of at-risk components of fictional suicidal behavior depicted in films, series, or television shows

The pH-sensitive properties of azo dyes in aqueous environment

Azo dyes consist of a double nitrogen-nitrogen bond connected to two aromatic moieties, creating a large conjugated pi-system. A relatively simple synthesis and large variety of colours have made azo dyes the most abundant class of colourants. The dye studied in this research, ethyl orange (EO), is a prototypical example of a halochromic (pH-sensitive) azo dye. Halochromic dyes have already proven useful for application in textile sensors since the colour change of such sensors is easy to perceive and the advantages of the parent materials (e.g. flexibility) are maintained.[1] The key to further development of smart materials is combining multiple responses that can be separately addressed by different triggers.[2] To achieve this, we need a full knowledge of the colour changing mechanism and the influence of the environment. Herein, both theoretical and experimental methods were used to unravel the halochromic properties of EO.[3] Experimental UV-VIS and Raman spectra point towards a structural change of EO in water between pH 5 and pH 3. This pH-sensitivity is modeled through a series of ab initio computations on the neutral, various singly and doubly protonated structures. Static calculations (with inclusion of implicit solvation) are successful in assigning the most probable protonation site. However, to fully understand the origin of the main absorption peaks, a molecular dynamics simulation study in a water molecular environment is used in combination with Time Dependent-DFT calculations to deduce average UV-VIS spectra which take into account the flexibility of the dye and the explicit interactions with the surrounding water molecules. The proposed methodology allows to achieve a remarkable agreement between the theoretical and experimental UV-VIS spectrum and enables to fully unravel the pH sensitive behaviour of EO in aqueous environment. References: [1] L. Van der Schueren and K. De Clerck, Textile Research Journal 80(7) 590-603 (2010). [2] M. A. C. Stuart et al., Nature Materials, 9(2) 101-113 (2010). [3] T. De Meyer et al., submitted to Chemistry - A European Journa

Towards the Industrialization of New MDO Methodologies and Tools for Aircraft Design

An overall summary of the Institute of Technology IRT Saint Exupery MDA-MDO project (Multi-Disciplinary Analysis - Multidisciplinary Design Optimization) is presented. The aim of the project is to develop efficient capabilities (methods, tools and a software platform) to enable industrial deployment of MDO methods in industry. At IRT Saint Exupery, industrial and academic partners collaborate in a single place to the development of MDO methodologies; the advantage provided by this mixed organization is to directly benefit from both advanced methods at the cutting edge of research and deep knowledge of industrial needs and constraints. This paper presents the three main goals of the project: the elaboration of innovative MDO methodologies and formulations (also referred to as architectures in the literature 1) adapted to the resolution of industrial aircraft optimization design problems, the development of a MDO platform featuring scalable MDO capabilities for transfer to industry and the achievement of a simulation-based optimization of an aircraft engine pylon with industrial Computational Fluid Dynamics (CFD) and Computational Structural Mechanics (CSM) tools

Groundwater Isolation Governs Chemistry and Microbial Community Structure along Hydrologic Flowpaths

International audienceThis study deals with the effects of hydrodynamic functioning of hard-rock aquifers on microbial communities. In hard-rock aquifers, the heterogeneous hydrologic circulation strongly constrains groundwater residence time, hydrochemistry, and nutrient supply. Here, residence time and a wide range of environmental factors were used to test the influence of groundwater circulation on active microbial community composition, assessed by high throughput sequencing of 16S rRNA. Groundwater of different ages was sampled along hydrogeologic paths or loops, in three contrasting hard-rock aquifers in Brittany (France). Microbial community composition was driven by groundwater residence time and hydrogeologic loop position. In recent groundwater, in the upper section of the aquifers or in their recharge zone, surface water inputs caused high nitrate concentration and the predominance of putative denitrifiers. Although denitrification does not seem to fully decrease nitrate concentrations due to low dissolved organic carbon concentrations, nitrate input has a major effect on microbial communities. The occurrence of taxa possibly associated with the application of organic fertilizers was also noticed. In ancient isolated groundwater, an ecosystem based on Fe(II)/Fe(III) and S/SO4 redox cycling was observed down to several 100 of meters below the surface. In this depth section, microbial communities were dominated by iron oxidizing bacteria belonging to Gallionellaceae. The latter were associated to old groundwater with high Fe concentrations mixed to a small but not null percentage of recent groundwater inducing oxygen concentrations below 2.5 mg/L. These two types of microbial community were observed in the three sites, independently of site geology and aquifer geometry, indicating hydrogeologic circulation exercises a major control on microbial communities

Gaia Data Release 2 Mapping the Milky Way disc kinematics

Context. The second Gaia data release (Gaia DR2) contains high-precision positions, parallaxes, and proper motions for 1.3 billion sources as well as line-of-sight velocities for 7.2 million stars brighter than G(RVS) = 12 mag. Both samples provide a full sky coverage. Aims. To illustrate the potential of Gaia DR2, we provide a first look at the kinematics of the Milky Way disc, within a radius of several kiloparsecs around the Sun. Methods. We benefit for the first time from a sample of 6.4 million F-G-K stars with full 6D phase-space coordinates, precise parallaxes (sigma((omega) over bar)/(omega) over bar Results. Gaia DR2 allows us to draw 3D maps of the Galactocentric median velocities and velocity dispersions with unprecedented accuracy, precision, and spatial resolution. The maps show the complexity and richness of the velocity field of the galactic disc. We observe streaming motions in all the components of the velocities as well as patterns in the velocity dispersions. For example, we confirm the previously reported negative and positive galactocentric radial velocity gradients in the inner and outer disc, respectively. Here, we see them as part of a non-axisymmetric kinematic oscillation, and we map its azimuthal and vertical behaviour. We also witness a new global arrangement of stars in the velocity plane of the solar neighbourhood and in distant regions in which stars are organised in thin substructures with the shape of circular arches that are oriented approximately along the horizontal direction in the U - V plane. Moreover, in distant regions, we see variations in the velocity substructures more clearly than ever before, in particular, variations in the velocity of the Hercules stream. Conclusions. Gaia DR2 provides the largest existing full 6D phase-space coordinates catalogue. It also vastly increases the number of available distances and transverse velocities with respect to Gaia DR1. Gaia DR2 offers a great wealth of information on the Milky Way and reveals clear non-axisymmetric kinematic signatures within the Galactic disc, for instance. It is now up to the astronomical community to explore its full potential.Peer reviewe

Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe