63 research outputs found
Niche Variation in Endemic Lilium pomponium on a Wide Altitudinal Gradient in the Maritime Alps
The relationship between altitudinal and ecological gradients has long been a dominant theme in plant ecology; moreover, how species respond to climate change has renewed this interest. Mediterranean mountains are often hotspots of endemism, and some endemic species have local distributions that span different climatic belts; hence, local variations in topography and fine-scaled niche conditions may play crucial roles in their persistence along such gradients. Studies of the fine-scaled niche are, however, very rare; most studies involve broad-scale variations in climatic parameters. The Turban lily, Lilium pomponium L. is endemic to the Maritime and Ligurian Alps, where it occurs across a wide altitudinal gradient. Previous work has shown no link between climatic marginality and geographic range limits on morphological traits and genetic variability; however, possible variations of local topographic and ecological parameters have not yet been examined. The objective of this paper is to characterise local ecological niche conditions of L. pomponium populations in the different bioclimatic zones it occupies along the altitudinal gradient. The species occurs in four main types of microecological niches. One of these niche types, with a high mineral cover, is the most abundantâtype 2: it was detected in 39% of sampled quadrats and occurs across the whole bioclimatic gradient. Other niche types are more limited to subsections of the gradient: type 3 (in 19% of sampled quadrats) is restricted to high-altitude sites (>1070 m.a.s.l.) and is characterised by high vegetation and litter cover; type 4 (26%) corresponds to more forested habitats on substrates with low water retention capacities, in more inland zones close to the centre of L. pomponium distribution and across a range of altitudes; and type 1 (16% of quadrat) only occurs in the Mediterranean part of the gradient, close to distribution limits in pockets of soil among large blocks of rocks, mainly found at mid-altitudes. Despite heterogeneity in the spatial locations of niche types, there is no correspondence between ecological gradients and the distribution limits of this species. Knowledge of the fine-scaled ecological conditions that determine niche types is thus essential for conservation management of the habitats of this species and for the exploration of its possible response to ongoing climate change
Solitary Fibrous Tumors and So-Called Hemangiopericytoma
We have reviewed the literature data regarding the spectrum of tumors including solitary fibrous tumor and hemangiopericytoma with special focus on definition of the disease, discussion of the criteria for malignancy, and the key elements of standard treatment of localized disease. We have discussed the emerging concepts on the tumor biology and the different systemic treatments (chemotherapy and molecular-targeted therapies)
Hierarchization of priorities for an action plan for the protected flora in the Pyrénées National Park
In this paper we adapt a recently developed objective framework to assess which species
may require monitoring, vigilance or enhanced prospection for the protected flora (124 taxa) present in the
Pyrenees National Park (France). The method is based on three criteria : regional responsibility, local rarity
and habitat vulnerability. The first two criteria were quantified by adapting classes according to previous
work. The vulnerability criterion was quantified using three main parameters : the priority and conservation
status of the habitat of each species combined with the proportion of known occurrences of the species in
the « adhesion » area of the park which is not subject to regulatory control. Each species was ranked within
a hierarchy developed in collaboration with the different park staff which allowed precise taxa to be selected
for monitoring, vigilance and prospectionL'objectif de ce travail est de proposer une hiérarchisation des priorités pour la flore protégée du Parc national des Pyrénées (PNP). Une méthodologie objective basée sur trois critÚres, la responsabilité patrimoniale des taxons,
leur rareté locale et la vulnérabilité de leur habitat, a donc été appliquée aux 124 taxons protégés présents sur ce territoire. Nous avons classé les taxons en adaptant les critÚres de responsabilité patrimoniale et de rareté au contexte biogéographique du PNP. Pour la vulnérabilité des
habitats, nous avons mené un travail approfondi afin de quantifier ce critÚre en tenant compte de la priorité des habitats, de leur état de conservation et de la proportion de stations dans l'Aire Optimale d'Adhésion. Le renseignement de ces critÚres a permis d'élaborer une hiérarchisation
qui, aprĂšs avis des agents du PNP, met en Ă©vidence les taxons les plus pertinents en termes de suivis, de veille ou de prospection
A hybrid Si@FeSiy/SiOx anode structure for high performance lithium-ion batteries via ammonia-assisted one-pot synthesis
Synthesised via planetary ball-milling of Si and Fe powders in an ammonia (NH3) environment, a hybrid Si@FeSiy/SiOx structure shows exceptional electrochemical properties for lithium-ion battery anodes, exhibiting a high initial capacity of 1150 mA h gâ1 and a retention capacity of 880 mA h gâ1 after 150 cycles at 100 mA gâ1; and a capacity of 560 mA h gâ1 at 4000 mA gâ1. These are considerably high for carbon-free micro-/submicro-Si-based anodes. NH3 gradually turns into N2 and H2 during the synthesis, which facilitates the formation of highly conductive FeSiy (y = 1, 2) phases, whereas such phases were not formed in an Ar atmosphere. Milling for 20â40 h leads to partial decomposition of NH3 in the atmosphere, and a hybrid structure of a Si core of mixed nanocrystalline and amorphous Si domains, shelled by a relatively thick SiOx layer with embedded FeSi nanocrystallites. Milling for 60â100 h results in full decomposition of NH3 and a hybrid structure of a much-refined Si-rich core surrounded by a mantle of a relatively low level of SiOx and a higher level of FeSi2. The formation mechanisms of the SiOx and FeSiy phases are explored. The latter structure offers an optimum combination of the high capacity of a nanostructural Si core, relatively high electric conductivity of the FeSiy phase and high structural stability of a SiOx shell accommodating the volume change for high performance electrodes. The synthesis method is new and indispensable for the large-scale production of high-performance Si-based anode materials
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Soft X ray spectroscopy of light elements in energy storage materials
The increasing demand for electrochemical energy storage devices continuously promotes the development of new electrode materials and electrolytes. As a result, understanding their structural and electronic properties affecting electrochemical performance becomes crucial. The role of light elements, which are found in anode and cathode materials, in electrolytes and hence in the solid-electrolyte interphases, requires a special attention. Soft X-ray spectroscopies are particularly relevant to probe selectively light elements in complex environment. Here, the recent advances in the characterization of light elements in energy storage materials by soft X-ray spectroscopy and microscopy techniques are reviewed. After introducing the main X-ray spectroscopic methods and their application to ex situ/in situ/operando characterization of electrochemical processes, the role of light elements in the electrode for supercapacitors and Li/Na-ion storage applications is described. The characterization of electrolytes and related ion solvation is then briefly reviewed before describing how the formation and evolution of solid-electrolyte interphases can be monitored with these methods. Finally, major challenges and future opportunities for soft X-rays spectroscopy in the context of electrochemical energy storage are highlighted
Exploring vulnerability of listed Mediterranean plants in relation to risks of population loss
International audienceIn this paper, we propose a method to assess population numbers and quantify their vulnerability for listed plant species. For six study species, the spatial aggregation of point data allowed us to identify the numbers of populations for each species and thus how they differ in regional abundance. We assessed vulnerability by according a score to each population in relation to three criteria: (i) land-use (urbanisation, agriculture and natural areas), (ii) fragmentation of populations by infrastructures and (iii) protected status of populations. As a result of the combination and scoring of populations across the three criteria, only 9% have a low extinction risk and 73% are in one of the three classes of high vulnerability with 16% in the highest category. Finally, 29 of 32 populations monitored in a separate study are in one of the three highest categories of vulnerability. This study illustrates how information on population numbers of listed species at the regional scale brings to the fore their generalised vulnerability to threats in the Mediterranean landscape. This information is vital for conservation management staff to develop a strategy and appropriate actions for listed species' protection
HiĂ©rarchisation des prioritĂ©s pour un plan dâaction pour la flore protĂ©gĂ©e du territoire du parc national des PyrĂ©nĂ©es
In this paper we adapt a recently developed objective framework to assess which species may require monitoring, vigilance or enhanced prospection for the protected flora (124 taxa) present in the Pyrenees National Park (France). The method is based on three criteria : regional responsibility, local rarity and habitat vulnerability. The first two criteria were quantified by adapting classes according to previous work. The vulnerability criterion was quantified using three main parameters : the priority and conservation
status of the habitat of each species combined with the proportion of known occurrences of the species in the «adhesion » area of the park which is not subject to regulatory control. Each species was ranked within
a hierarchy developed in collaboration with the different park staff which allowed precise taxa to be selected
for monitoring, vigilance and prospection.Lâobjectif de ce travail est de proposer une hiĂ©rarchisation des prioritĂ©s pour la flore protĂ©gĂ©e du Parc national des PyrĂ©nĂ©es (PNP). Une mĂ©thodologie objective basĂ©e sur trois critĂšres, la responsabilitĂ© patrimoniale des taxons, leur raretĂ© locale et la vulnĂ©rabilitĂ© de leur habitat, a donc Ă©tĂ© appliquĂ©e aux 124 taxons protĂ©gĂ©s prĂ©sents sur ce territoire. Nous avons classĂ© les taxons en adaptant les critĂšres de responsabilitĂ© patrimoniale et de raretĂ© au contexte biogĂ©ographique du PNP. Pour la vulnĂ©rabilitĂ© des habitats, nous avons menĂ© un travail approfondi afin de quantifier ce critĂšre en tenant compte de la prioritĂ© des
habitats, de leur Ă©tat de conservation et de la proportion de stations dans lâAire Optimale dâAdhĂ©sion. Le
renseignement de ces critĂšres a permis dâĂ©laborer une hiĂ©rarchisation qui, aprĂšs avis des agents du PNP, met en Ă©vidence les taxons les plus pertinents en termes de suivis, de veille ou de prospection.Foulon Yoann, Gauthier Perrine, Jupille Olivier, Thompson John D. HiĂ©rarchisation des prioritĂ©s pour un plan dâaction pour la flore protĂ©gĂ©e du territoire du parc national des PyrĂ©nĂ©es. In: Revue d'Ăcologie (La Terre et La Vie), tome 68, n°3-4, 2013. pp. 213-229
Mixed camera angles viewpoints improve learning medical hand procedure in nurse training
Communication donnée le 31 Août 2017 lors de la session J 10 : Instructional Design, Learning and Instructional TechnologyComprehension of Text and Graphics - CInternational audienceFew previous research showed that camera viewpoints differences played a role in learning hand procedures from videos. However, learning videos on hand procedures showing only single viewpoints have been investigated, for example face to face vs. over the shoulder views. Further, the effect of seeing the human model's face and the effect of showing hand actions have also been studied. The results of these research are not always consistent. The goal of the present research was to investigate the effect of mixed camera viewpoints on learning a medical hand procedure from a video. Within a pretest-posttest paradigm, 43 students from a French institute of nursing education had to learn a complex hand procedure from a video showing an expert nursing teacher who installed an indwelling catheter in a closed system. Three videos conditions were compared showing the hand procedure respectively from (i) a face to face view (FtF), an over-the shoulder view (OtS) and (iii) an alternation of face to face and over the shoulder views (MixW). The students were randomly assigned (N =10-11) to one of four groups: the three experimental viewing conditions (FtF, OsS, MixW) and a control condition, without video. Pre and post-test consisted in the demonstration of the hand procedure in a full scale simulation room fully equipped. Results showed that learners in the mixed viewpoint (MixW) group performed better than the other groups (FtF, OsS, MixW and control condition). Learners in the FtF and OsS groups had betters scores than learners in the control group
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