415 research outputs found
Interprétation et quête de la vérité par la fiction : Scènes d’enfants de Normand Chaurette
No full textOeuvre de fiction en même temps que critique de la fiction, le roman Scènes d'enfants de Normand Chaurette fictionnalise la problématique interprétative au point d'en faire le coeur même de sa diégèse. Observant l'herméneutique littéraire à l'oeuvre dans le roman, cet article se propose de questionner l'activité interprétative des divers protagonistes en présence, un "faire herméneutique" placé sous le signe de l'hybridation, du brouillage et de l'indécidabilité.As both work of fiction and criticism of fiction, Normand Chaurette's novel Scènes d'enfants fictionalises the interpretive problematic to the point of making it the heart of its diegesis. Observing the literary hermeneutics at work in the novel, this article questions the specific view of literature arising from the interpretive activity of the various protagonists - a "hermeneutic making" placed under the sign of hybridization, jamming and undecidability
Chemical signature in xylem cell wall of Salix glauca L. due to Eurois occulta L. outbreaks
No full textInsects driven defoliations are one of the major natural disturbances in high-latitude ecosystems and are expected to increase in frequency and severity due to global climate change. Defoliations cause severe reductions in biomass and carbon investments that affect the functioning and productivity of tundra ecosystems. Recent studies have quantified the decrease in cell-wall thickness (CWT) during the outbreak and the unexpected increase in primary production the following years. Here we combine dendro-anatomical analysis with chemical imaging to investigate how the outbreaks affect carbon assimilation and vegetation productivity.
Samples of Salix glauca L. featuring outbreak events of the moth Eurois occulta L. were collected at Iffiarterfik, Western Greenland. Samples were cross-dated and two pointer years in 2003 and 2010 (outbreaks) identified. These two annual rings showed a clear reduction in carbon investment such as reduction in ring-width, CWT but also colour intensity was affected, suggesting an altered biopolymer mark-up.
For each outbreak event, seven growth rings were analysed (outbreak ±3years). The wider rings formed the two following years highlighted a growth release after the outbreaks. The chemical composition of the xylem cell wall material was analysed using confocal Raman imaging on cross sections of fibres, vessels, and parenchyma cells to possibly identify the chemical signatures related to insect outbreaks. Possible differences in chemical composition between cell types and between growth years were explored using chemical imaging based on cluster analysis of integrated Raman band intensities as well as by more advanced chemometric approaches
Improving ecological insights from dendroecological studies of Arctic shrub dynamics: Research gaps and potential solutions
No full textRapid climate change has been driving changes in Arctic vegetation in recent decades, with increased shrub
dominance in many tundra ecosystems. Dendroecological observations of tundra shrubs can provide insight
into current and past growth and recruitment patterns, both key components for understanding and predicting
ongoing and future Arctic shrub dynamics. However, generalizing these dynamics is challenging as they are
highly scale-dependent and vary among sites, species, and individuals. Here, we provide a perspective on how
some of these challenges can be overcome. Based on a targeted literature search of dendrochronological studies
from 2005 to 2022, we highlight five research gaps that currently limit dendro-based studies from revealing
cross-scale ecological insight into shrub dynamics across the Arctic biome. We further discuss the related re-
search priorities, suggesting that future studies could consider: 1) increasing focus on intra- and interspecific var-
iation, 2) including demographic responses other than radial growth, 3) incorporating drivers, in addition to
warming, at different spatial and temporal scales, 4) implementing systematic and unbiased sampling ap-
proaches, and 5) investigating the cellular mechanisms behind the observed responses. Focusing on these aspects
in dendroecological studies could improve the value of the field for addressing cross-scale and plant community-
framed ecological questions. We outline how this could be facilitated through the integration of community-
based dendroecology and dendroanatomy with remote sensing approaches. Integrating new technologies and
a more multidisciplinary approach in dendroecological research could provide key opportunities to close impor-
tant knowledge gaps in our understanding of scale-dependencies, as well as intra- and inter-specific variation, in
vegetation community dynamics across the Arctic tundra.Marie Skłodowska-Curie Action. Uncovering the anatomical archive of annual RINGS to understand abiotic and biotic drivers of SHRUB growth at the range BORDER (BoRiS). Grant agreement no. 89523
Evidences of cyclic Eurois occulta outbreaks in West Greenland based on shrub-ring anatomy and remote sensing
No full textInsect outbreaks are among the major disturbances in high latitude ecosystems. Such outbreaks cause severe canopy defoliation and reduce the vegetation biomass and C investments, with potential consequences for species composition, functioning and productivity of tundra ecosystems. Outbreaks are expected to increase in severity and frequency in the future due to climate changes. Despite their importance, up to now only few studies tried a retrospective reconstruction of past outbreaks, and none has investigated their effect on shrub anatomical structure, e.g., cell wall thickness. In this research, we use a dendro-anatomical approach combined with remotely sensed data to assess and reconstruct past outbreaks of the moth Eurois occulta in West Greenland. We additionally quantify changes in annual growth and C investment for the host species Salix glauca L.
We analysed Salix glauca L. samples collected along the Nuuk fjord (7 sites, 136 samples) to identify outbreak events and quantify inter-annual variation in conduit diameters and wall thickness. Time series of Landsat images were used to detect NDVI deviations caused by reductions in the photosynthetic activity in the area. Wood samples were successfully crossdated and 7 chronologies were established spanning more than 50 years. We clearly identified three distinctive pointer years of reduced annual growth (1997, 2003 and 2010), where wood-anatomical traits showed either a significant reduction in cell-wall thickness or no variation in vessel size. This implies that under defoliations Salix glauca L. undergoes an adjustment in the xylem traits aimed to maintain the hydraulic structure but with a detrimental effect on fiber cell walls.
This multi-proxy approach allowed us to distinguish between abiotic (climate) and biotic (the moth) drivers of narrow ring formation
La chasse au chevreuil chez les frères Normand dans les Cantons de l’Est
No full textCe texte a été produit dans le cadre d’un séminaire de maîtrise en sociologie à la fin des années 1970. À la suite d’enquêtes orales auprès de ses quatre frères, l’auteure s’est d’abord attardée à étudier cette chasse, à en décrire sa structure, son organisation et son déroulement. Par la suite, cette chasse a été analysée sous les angles de la fête, de la cérémonie et du jeu. Cette recherche lui a permis de préciser son projet de mémoire de maîtrise et de circonscrire son nouveau terrain de prédilection : la nouvelle vie sur les terres acquises et cultivées par les cinq familles immigrées de Charlevoix à la fin des années 1910 sous l’impulsion de son père François, organisateur de cette migration dans les Cantons de l’Est.This text was produced in the course of a Masters seminar in sociology at the end of the 1970s. Having carried out oral interviews with her four brothers, the author set out to study deer hunting practises, describing the structure, the organization and the process followed during the hunt. In the project’s second phase, deer hunting was analyzed as a type of ceremony accompanied by gaming rituals and celebrations. Thanks to this research project, the author was able to choose her Masters dissertation topic, and to define a new area of research : the lives of five families of migrants from the Charlevoix region who settled on farmlands obtained with help from the author’s father, François, in the Eastern Townships at the end of the 1910s
The soft-focus lens and Anglo-American pictorialism
No full textElectronic version excludes illustrations for which permission has not been granted by the rights holderThe history, practice and aesthetic of the soft focus lens in photography is elucidated and developed from its earliest statements of need to the current time with a particular emphasis on its role in the development of the Pictorialist movement. Using William Crawford's concept of photographic 'syntax', the use of the soft focus lens is explored as an example of how technology shapes style.
A detailed study of the soft focus lenses from the earliest forms to the present is presented, enumerating the core properties of pinhole, early experimental and commercial soft focus lenses. This was researched via published texts in period journals, advertising, private correspondence, interviews, and the lenses themselves. The author conducted a wide range of in-studio experiments with both period and contemporary soft focus lenses to evaluate their character and distinct features, as well as to validate source material.
Nodal points of this history and development are explored in the critical debate between the diffuse and sharp photographic image, beginning with the competition between the calotype and daguerreotype. The role of George Davison's The Old Farmstead is presented as well as the invention of the first modern soft focus lens, the Dallmeyer-Bergheim, and its function in the development of the popular Pictorialist lens, the Pinkham & Smith Semi-Achromatic. The trajectory of the soft focus lens is plotted against the Pictorialist movement, noting the correlation betwixt them, and the modern renaissance of soft focus lenses and the diffuse aesthetic.
This thesis presents a unique history of photography modeled around the determining character of technology and the interdependency of syntax, style and art
Postglacial migration supplements climate in determining plant species ranges in Europe
No full textThe influence of dispersal limitation on species ranges remains controversial. Considering the dramatic impacts of the last glaciation in Europe, species might not have tracked climate changes through time and, as a consequence, their present-day ranges might be in disequilibrium with current climate. For 1016 European plant species, we assessed the relative importance of current climate and limited postglacial migration in determining species ranges using regression modelling and explanatory variables representing climate, and a novel species-specific hind-casting-based measure of accessibility to postglacial colonization. Climate was important for all species, while postglacial colonization also constrained the ranges of more than 50 per cent of the species. On average, climate explained five times more variation in species ranges than accessibility, but accessibility was the strongest determinant for one-sixth of the species. Accessibility was particularly important for species with limited long-distance dispersal ability, with southern glacial ranges, seed plants compared with ferns, and small-range species in southern Europe. In addition, accessibility explained one-third of the variation in species' disequilibrium with climate as measured by the realized/potential range size ratio computed with niche modelling. In conclusion, we show that although climate is the dominant broad-scale determinant of European plant species ranges, constrained dispersal plays an important supplementary role
Conseguenze delle pullulazioni di Eurois occulta sulla crescita della vegetazione in Groenlandia occidentale valutate da scala cellulare a satellitare
No full textEcoDes-DK15: High-resolution ecological descriptors of vegetation and terrain derived from Denmark's national airborne laser scanning data set
No full textEighteen high-resolution ecological descriptors of vegetation and terrain for Denmark "EcoDes-DK15"
The data are derived from the nationwide airborne laser scanning / LiDAR campaign of Denmark from 2014-2015 provided by the Danish Agency for Data Supply and Efficiency.
Update: EcoDes-DK15 v1.1.0 (4 Dec. 2021)
Following the recommendations and feedback during the first round of peer-review, we updated the EcoDes-DK processing pipeline and EcoDes-DK15 data set. The key changes are:
New version of the source data optimised to contain only point data collected before the end of 2015. The source data for EcoDes-DK15 v1.0.0 unintentionally contained data from 2018. The new source data is documented here.
New "date_stamp_*" auxiliary variables that illustrate the survey dates for the vegetation points in each cell. See updated descriptor documentation here.
Re-scaling of "solar_radiation" variable to MJ per 100 m2 per year.
Detailed documentation for the data set can be found in the accompanying manuscript and GitHub repository:
Assmann, J. J., Moeslund, J. E., Treier, U. A., and Normand, S.: EcoDes-DK15: High-resolution ecological descriptors of vegetation and terrain derived from Denmark's national airborne laser scanning data set, Earth Syst. Sci. Data Discuss. [preprint], https://doi.org/10.5194/essd-2021-222, in review, 2021.
https://github.com/jakobjassmann/ecodes-dk-lidar
Files are compressed using bzip2 and tar archiving. The compressed archives can be extracted using commonly available archiving tools (for example 7z on Windows, the archiving tool on macOS and bz2 on Linux).
A small example "teaser" subset (5 MB) of the data set, covering the Husby Klit area from Figure 7 in the manuscript, can be found here.
Abstract (from manuscript)
Biodiversity studies could strongly benefit from three-dimensional data on ecosystem structure derived from contemporary remote sensing technologies, such as Light Detection and Ranging (LiDAR). Despite the increasing availability of such data at regional and national scales, the average ecologist has been limited in accessing them due to high requirements on computing power and remote-sensing knowledge. We processed Denmark’s publicly available national Airborne Laser Scanning (ALS) data set acquired in 2014/15 together with the accompanying elevation model to compute 70 rasterized descriptors of interest for ecological studies. With a grain size of 10 m, these data products provide a snapshot of high-resolution measures including vegetation height, structure and density, as well as topographic descriptors including elevation, aspect, slope and wetness across more than forty thousand square kilometres covering almost all of Denmark’s terrestrial surface. The resulting data set is comparatively small (~94 GB, compressed 16.8 GB) and the raster data can be readily integrated into analytical workflows in software familiar to many ecologists (GIS software, R, Python). Source code and documentation for the processing workflow are openly available via a code repository, allowing for transfer to other ALS data sets, as well as modification or re-calculation of future instances of Denmark’s national ALS data set. We hope that our high-resolution ecological vegetation and terrain descriptors (EcoDes-DK15) will serve as an inspiration for the publication of further such data sets covering other countries and regions and that our rasterized data set will provide a baseline of the ecosystem structure for current and future studies of biodiversity, within Denmark and beyond.
Acknowledgements (from manuscript)
We would like to thank Andràs Zlinszky for his contributions to earlier versions of the data set, Charles Davison for feedback regarding data use and handling, as well as Matthew Barbee and Zsófia Koma for sharing their insights on the source data merger and Zsófia’s script to generate summary statistics for the different versions of the DHM point clouds. Funding for this work was provided by the Carlsberg Foundation (Distinguished Associate Professor Fellowships) and Aarhus University Research Foundation (AUFF-E-2015-FLS-8-73) to Signe Normand (SN). This work is a contribution to SustainScapes – Center for Sustainable Landscapes under Global Change (grant NNF20OC0059595 to SN)
La Sicile, carrefour des cultures en Méditerranée au XII e siècle : Al-Idrîsî, Livre de Roger (vue de la Sicile)
No full textAu carrefour des trois mondes, normand, arabe et byzantin, le royaume de Sicile, fondé en 1130 par Roger II, prince normand, est l’exemple de l’interpénétration des cultures sous le signe de la tolérance. Chacun pratique librement son culte. A la cour, on parle l’arabe autant que le français mais aussi le latin et le grec. Nos valeurs républicaines auront la force de l'exemplarité en Europe et dans le monde si notre République est dans la réalité des faits ce qu'elle déclare être dans la Constitution : démocratique, laïque et sociale.téléchargeabl
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