34 research outputs found
L'exil de Jan Cep (contribution à l'histoire de la littérature tchèque moderne)
No full textL écrivain tchèque Jan Cep (1902-1974), qui compta au nombre des médiateurs importants des rapports culturels franco-tchèques dans l entre-deux-guerres, fut, à la suite du Coup de Prague en 1948, contraint à quitter son pays. Ami et traducteur de Pourrat et de Bernanos, il choisit naturellement la France comme patrie d adoption. L exil parisien s avère pour Cep une rude épreuve existentielle. Conditions matérielles dures, déracinement linguistique, manque d écho favorable pour son oeuvre, tout cela fait que Cep vit en marge de la vie littéraire française. Il s engage d autant plus dans diverses structures de l émigration tchèque, notamment dans la rédaction tchécoslovaque de Radio Free Europe où il déploie son art de l essai dans des méditations imprégnées d humanisme chrétien. L essai autobiographique Ma soeur l angoisse que Cep écrivit directement en français dans les années 1960, représente la somme de sa vie et de sa penséeThe Czech writer Jan Cep (1902-1974), one of important mediators of French-Czech cultural relations between the two World Wars, was forced to emigrate after the Communist coup in 1948. As Cep was the friend and translator of Pourrat and Bernanos, he naturally chose France as his adoptive homeland. Nevertheless, exile in Paris turned into a harsh existential ordeal for Cep. Difficult material conditions, linguistic disunity, and the fact that his writing was not accepted by a new audience made Cep an outsider in a French literary life. This status led to his increased involvement in the Czech émigré community, especially work on the Czechoslovak editorial staff of Radio Free Europe, where he developed his essay style in meditations infused with Christian humanism. The autobiographical essay My Sister Anxiety, written in French in the 1960s, repesents a summary of Cep s life and ideasPARIS-EST-Université (770839901) / SudocPARIS12-Bib. électronique (940280011) / SudocSudocFranceF
Long-Term Accumulation, Biological Effects and Toxicity of BSA-Coated Gold Nanoparticles in the Mouse Liver, Spleen, and Kidneys
No full textKristina Jakic,1 Michal Selc,1,2 Filip Razga,3 Veronika Nemethova,3 Petra Mazancova,3 Filip Havel,4,5 Michal Sramek,5 Monika Zarska,5 Jan Proska,4 Vlasta Masanova,6 Iveta Uhnakova,6 Peter Makovicky,7 Marta Novotova,8 Vit Vykoukal,9 Andrea Babelova1,2 1Department of Nanobiology, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia; 2Centre for Advanced Material Application, Slovak Academy of Sciences, Bratislava, Slovakia; 3Selecta Biotech SE, Bratislava, Slovakia; 4Department of Physical Electronics, Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic; 5Department of Genome Integrity, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic; 6Department of Metallomics, Faculty of Medicine, Slovak Medical University, Bratislava, Slovakia; 7Department of Molecular Oncology, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia; 8Department of Cellular Cardiology, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia; 9Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech RepublicCorrespondence: Andrea Babelova, Department of Nanobiology, Cancer Research Institute, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia, Tel +421-2-32295-189, Fax +421-2-5477-4284, Email [email protected]: Gold nanoparticles are promising candidates as vehicles for drug delivery systems and could be developed into effective anticancer treatments. However, concerns about their safety need to be identified, addressed, and satisfactorily answered. Although gold nanoparticles are considered biocompatible and nontoxic, most of the toxicology evidence originates from in vitro studies, which may not reflect the responses in complex living organisms.Methods: We used an animal model to study the long-term effects of 20 nm spherical AuNPs coated with bovine serum albumin. Mice received a 1 mg/kg single intravenous dose of nanoparticles, and the biodistribution and accumulation, as well as the organ changes caused by the nanoparticles, were characterized in the liver, spleen, and kidneys during 120 days.Results: The amount of nanoparticles in the organs remained high at 120 days compared with day 1, showing a 39% reduction in the liver, a 53% increase in the spleen, and a 150% increase in the kidneys. The biological effects of chronic nanoparticle exposure were associated with early inflammatory and fibrotic responses in the organs and were more pronounced in the kidneys, despite a negligible amount of nanoparticles found in renal tissues.Conclusion: Our data suggest, that although AuNPs belong to the safest nanomaterial platforms nowadays, due to their slow tissue elimination leading to long-term accumulation in the biological systems, they may induce toxic responses in the vital organs, and so understanding of their long-term biological impact is important to consider their potential therapeutic applications. Keywords: AuNPs, in vivo, long-term accumulation, biodistribution, inflammation, fibrosi
Observation on the Apiosoma piscicola under optical and transmission electron microscope
No full textAs a species of the epizootic ciliate, Apiosoma piscicola Blanchard, 1885 which attaches to the surfaces of many kinds of hydrobionts can badly endanger the hosts and cause great losses to the aquaculture industry. It also has a wide spread, such as Europe, Asia and South Africa. Because of its great variability in different regions, Apiosoma piscicola (Blanchard, 1885) has some synonyms such as "Glossatella cyprinid Sramek-Husek, 1953", "Apiosoma magna Banina, 1968", etc. In China, it was firstly reported by Chen with the name "Glossatella cylindriformis" in 1956. Although Apiosoma piscicola was found more than one century before, today our understanding to them remains in the stage of alpha taxonomy. In order to carry out the research deeply, the author collected numerous specimens from the gills and fins of the fishes that were heavily infected in the Hongze Lake of Jiangsu Province located in east of China. This paper systematically dealt with the morphology and structure of the living specimens( stained with 2% Neutral Red)and fixed-stained specimens(the smears fixed in saturated HgCl2 solution and stained with Heidenhain's haematoxylin, Ehrlich's haematoxylin and the dry smears impregnated in 3% AgNO3 solution)under optical microscopy and the ultrastructure under transmission electron microscopy. Great diversities have been found on the sizes of the organisms (the length and width of the body, macronucleus and micronucleus)compared with the data of Hupei specimens and the reason was discussed. In addition, lots of bacteria and food particles were observed within the body of the organisms, especially around the peristomial disc under transmission electron microscopy. This phenomenon gives a strong support from the aspect of food sources to the viewpoint that Apiosoma is a kind of ectocommensals but not ectoparasites
A simple disc wind model for broad absorption line quasars
No full textApproximately 20 per cent of quasi-stellar objects (QSOs) exhibit broad, blue-shifted absorption lines in their ultraviolet spectra. Such features provide clear evidence for significant outflows from these systems, most likely in the form of accretion disc winds. These winds may represent the ‘quasar’ mode of feedback that is often invoked in galaxy formation/evolution models, and they are also key to unification scenarios for active galactic nuclei (AGN) and QSOs. To test these ideas, we construct a simple benchmark model of an equatorial, biconical accretion disc wind in a QSO and use a Monte Carlo ionization/radiative transfer code to calculate the ultraviolet spectra as a function of viewing angle. We find that for plausible outflow parameters, sightlines looking directly into the wind cone do produce broad, blue-shifted absorption features in the transitions typically seen in broad absorption line (BAL) QSOs. However, our benchmark model is intrinsically X-ray weak in order to prevent overionization of the outflow, and the wind does not yet produce collisionally excited line emission at the level observed in non-BAL QSOs. As a first step towards addressing these shortcomings, we discuss the sensitivity of our results to changes in the assumed X-ray luminosity and mass-loss rate, Ṁwind. In the context of our adopted geometry, Ṁwind ∼ Ṁacc is required in order to produce significant BAL features. The kinetic luminosity and momentum carried by such outflows would be sufficient to provide significant feedback
Emerging stability of forest productivity by mixing two species buffers temperature destabilizing effect
No full textInternational audienceThe increasing disturbances in monocultures around the world are testimony to their instability under global change. Many studies have claimed that temporal stability of productivity increases with species richness, although the ecological fundamentals have mainly been investigated through diversity experiments. To adequately manage forest ecosystems, it is necessary to have a comprehensive understanding of the effect of mixing species on the temporal stability of productivity and the way in which it is influenced by climate conditions across large geographical areas. Here, we used a unique dataset of 261 stands combining pure and two-species mixtures of four relevant tree species over a wide range of climate conditions in Europe to examine the effect of species mixing on the level and temporal stability of productivity. Structural equation modelling was employed to further explore the direct and indirect influence of climate, overyielding, species asynchrony and additive effect (i.e. temporal stability expected from the species growth in monospecific stands) on temporal stability in mixed forests. We showed that by adding only one tree species to monocultures, the level (overyielding: +6%) and stability (temporal stability: +12%) of stand growth increased significantly. We identified the key effect of temperature on destabilizing stand growth, which may be mitigated by mixing species. We further confirmed asynchrony as the main driver of temporal stability in mixed stands, through both the additive effect and species interactions, which modify between-species asynchrony in mixtures in comparison to monocultures. Synthesis and applications. This study highlights the emergent properties associated with mixing two species, which result in resource efficient and temporally stable production systems. We reveal the negative impact of mean temperature on temporal stability of forest productivity and how the stabilizing effect of mixing two species can counterbalance this impact. The overyielding and temporal stability of growth addressed in this paper are essential for ecosystem services closely linked with the level and rhythm of forest growth. Our results underline that mixing two species can be a realistic and effective nature-based climate solution, which could contribute towards meeting EU climate target policies
Mixing has limited impacts on the foliar nutrition of European beech and Scots pine trees across Europe
No full textTree species-mixing has been suggested as one option to counteract the adverse effects of global change on tree mineral nutrition, yet the effect of mixing on nutrient availability remains poorly documented. We therefore analyzed the current foliar nutrient (N, P, K, Ca, Mg) quantities and ilr balances (isometric log transformed ratios between elements or groups of elements) for 261 European beech and 248 Scots pine trees from 15 sites, each consisting of one beech-pine mixed stand and the respective monocultures, across a gradient of environmental conditions in Europe. We hypothesized an overall positive effect of mixing on tree foliar nutrient content, and that this mixing effect would be stronger on nutrient-poor sites. Using linear mixed models and multivariate linear regression models, we first tested for the effects of species (beech/pine) and composition (pure/mixed) across all sites; we then investigated whether the species-mixing effect was related to site fertility. The nutrient composition of beech leaves and pine needles differed significantly for all ilr balances. For both species, significant mixing effects were detected for some nutrients and ilr balances; those effects, however, could not be consistently related to contrasted nutrient composition between species. For most nutrients and ilr balances, the mixing effect was influenced by the site nutritional status, but the pattern differed from expectation: absence or minor differences between monocultures and mixtures at the lower end of the chemical fertility gradient, and maximum differences in rich soils. The contrasting foliar nutrient composition of pine and beech trees and the site nutrient status only partly explained the mixing effects on tree mineral nutrition. Our results claim for a better understanding of nutrientrelated mechanisms associated with complementarity and points towards the need to further expand the existing frameworks to account for the multivariate nature of tree nutrition
Optical polarimetry studies of Seyfert galaxies
No full textOptical imaging polarimetry has been performed on seven nearby Seyfert galaxies, three with face-on and four with edge-on host galaxies of various morphological classifications. Observations in V, R, B and H(_a) wavebands are presented as maps of total intensity and of polarized intensity, overlaid with polarization vectors. Independent determinations of the interstellar polarization (ISP) contribution from our own galaxy are made where possible, and are used to produce ISP corrected maps. The polarization patterns seen in the maps show evidence of either dichroic extinction, which indicates the presence of non-spherical dust grains in large-scale galactic magnetic fields, or scattering, which is due to the illumination of regions of dust grains or electrons. The polarization features, which are observed at the different wavebands, are then compared to recent models of polarization in external galaxies. Estimates of the intrinsic Seyfert nuclear polarization are made where possible by correcting for ISP and for an approximation of the dilution due to the host galaxy flux by using values from previous studies. Both the measured and the corrected nuclear polarizations are compared with previously published values, and are discussed in the context of the standard models of Seyfert galaxies. Most of the observed galaxies show evidence of polarization, both from the host galaxy and from the intrinsic Seyfert nucleus. In particular, distinct polarization features: bands of polarization consistent with extended dusty disks aligned with the dusty tori proposed in Seyferts, and regions of polarization corresponding to scattering of the nuclear continuum along the biconical extended Seyfert emission-line regions, have been identified in several of the observed galaxies
MRS Drone: A Modular Platform for Real-World Deployment of Aerial Multi-Robot Systems
No full textThis paper presents a modular autonomous Unmanned Aerial Vehicle (UAV)
platform called the Multi-robot Systems (MRS) Drone that can be used in a large
range of indoor and outdoor applications. The MRS Drone features unique
modularity with respect to changes in actuators, frames, and sensory
configuration. As the name suggests, the platform is specially tailored for
deployment within a MRS group. The MRS Drone contributes to the
state-of-the-art of UAV platforms by allowing smooth real-world deployment of
multiple aerial robots, as well as by outperforming other platforms with its
modularity. For real-world multi-robot deployment in various applications, the
platform is easy to both assemble and modify. Moreover, it is accompanied by a
realistic simulator to enable safe pre-flight testing and a smooth transition
to complex real-world experiments. In this manuscript, we present mechanical
and electrical designs, software architecture, and technical specifications to
build a fully autonomous multi UAV system. Finally, we demonstrate the full
capabilities and the unique modularity of the MRS Drone in various real-world
applications that required a diverse range of platform configurations.Comment: 49 pages, 39 figures, accepted for publication to the Journal of
Intelligent & Robotic System
EuMIXFOR empirical forest mensuration and ring width data from pure and mixed stands of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) through Europe
No full textKey message: This data set provides unique empirical data from triplets of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) across Europe. Dendrometric variables are provided for 32 triplets, 96 plots, 7555 trees and 4695 core samples. These data contribute to our understanding of mixed stand dynamics. Dataset access at http://dx.doi.org/10.5061/dryad.8v04m. Associated metadata available at https://metadata-afs.nancy.inra.fr/geonetwork/apps/georchestra/? uuid=b3e098ca-e681-4910-90990e25d3b4cd52&hl=eng
