Contribution of multi-temporal remote sensing images to characterize landslide slip surface ‒ Application to the La Clapière landslide (France)

Landslide activity is partly controlled by the geometry of the slip surface. This activity is traduced at the surface by displacements and topographic variations. Consequently, multi-temporal remote sensing images can be used in order to characterize the geometry of landslide slip surface and its spatial and temporal evolution. Differential Digital Elevation Models (DEMs) are obtained by subtracting two DEMs of different years. A method of multi-temporal images correlation allows to generate displacement maps that can be interpreted in terms of velocity and direction of movements. These data are then used to characterize qualitatively the geometry of the slip surface of the la Clapière landslide (French Southern Alps). Distribution of displacement vectors and of topographic variations are in accordance with a curved slip surface, characterizing a preferential rotational behaviour of this landslide. On the other hand, a spatial and temporal evolution of the geometry of the slip surface is pointed out. Indeed, a propagation of the slip surface under the Iglière bar, in the W part of the landslide, is suspected and can be linked to the acceleration of the landslide in 1987. This study shows the high potential of multi-temporal remote sensing images for slip surface characterization. Although this method could not replace in situ investigations, it can really help to well distribute geophysical profiles or boreholes on unstable areas

Probing DNA conformational changes with high temporal resolution by Tethered Particle Motion

The Tethered Particle Motion (TPM) technique informs about conformational changes of DNA molecules, e.g. upon looping or interaction with proteins, by tracking the Brownian motion of a particle probe tethered to a surface by a single DNA molecule and detecting changes of its amplitude of movement. We discuss in this context the time resolution of TPM, which strongly depends on the particle-DNA complex relaxation time, i.e. the characteristic time it takes to explore its configuration space by diffusion. By comparing theory, simulations and experiments, we propose a calibration of TPM at the dynamical level: we analyze how the relaxation time grows with both DNA contour length (from 401 to 2080 base pairs) and particle radius (from 20 to 150~nm). Notably we demonstrate that, for a particle of radius 20~nm or less, the hydrodynamic friction induced by the particle and the surface does not significantly slow down the DNA. This enables us to determine the optimal time resolution of TPM in distinct experimental contexts which can be as short as 20~ms.Comment: Improved version, to appear in Physical Biology. 10 pages + 10 pages of supporting materia

Critical exponents at the ferromagnetic transition in tetrakis(diethylamino)ethylene-C60_{60} (TDAE-C60_{60})

Critical exponents at the ferromagnetic transition were measured for the first time in an organic ferromagnetic material tetrakis(dimethylamino)ethylene fullerene[60] (TDAE-C$_{60}$). From a complete magnetization-temperature-field data set near $T_{c}=16.1\pm 0.05,$ we determine the susceptibility and magnetization critical exponents $\gamma =1.22\pm 0.02$ and $\beta =0.75 \pm 0.03$ respectively, and the field vs. magnetization exponent at $T_{c}$ of $\delta =2.28\pm 0.14$. Hyperscaling is found to be violated by $\Omega \equiv d^{\prime}-d \approx -1/4$, suggesting that the onset of ferromagnetism can be related to percolation of a particular contact configuration of C$_{60}$ molecular orientations.Comment: 5 pages, including 3 figures; to appear in Phys. Rev. Let

Descobrindo “para-formalidades”: atividades que gritam por espaço

A pesquisa trabalha no sentido de mapear e dar visibilidade às cenas “para-formais” encontradas no espaço público dos centros de cidades latinoamericanas. Entendemos “para-formal” como todas as atividades encontradas no espaço público da cidade que não fazem parte de seu desenho urbano (original), mas que “agora” fazem parte de seu cotidiano. A investigação se dá a partir de cartografias urbanas, fazendo uso de recursos infográficos e sendo divulgado em tempo real por meio de website. Destacamos as principais “paraformalidades” encontradas na maioria das cidades que estudamos: trailers, para-ciclos inventados, para-formal no formal, vendedores isolados móveis e o grandes conjuntos para-formais. Podemos adiantar que é possível compreender que esses equipamentos são parte da cidade e devem ser levados em consideração pelos arquitetos e urbanistas, tanto em novos projetos como em revitalizações arquitetônicas e urbanísticas.The research works towards mapping and profiling the scenes “para-formal” found in the public space of the centers of Latin American cities. We understand “para-formal” as all activities found in the public space of the city that are not part of their urban design (the original), but that “now” part of their daily lives. The research starts from urban cartography, making use of infographics and resources being released in real time via the website. Highlight the main “to-tape” found in most cities we studied: trailers, for-cycles invented, paraformal in the formal, isolated mobile sallers and large ensembles para-formals. We anticipate that it is possible to understand that the equipment is part of the city and should be considered by architects and planners, both in new projects such as in architectural and urban revitalization.Eje 3: Derecho a la ciudad: mutaciones, recomposiciones, adaptaciones, reformulaciones.Facultad de Arquitectura y Urbanism

Descobrindo “para-formalidades”: atividades que gritam por espaço

A pesquisa trabalha no sentido de mapear e dar visibilidade às cenas “para-formais” encontradas no espaço público dos centros de cidades latinoamericanas. Entendemos “para-formal” como todas as atividades encontradas no espaço público da cidade que não fazem parte de seu desenho urbano (original), mas que “agora” fazem parte de seu cotidiano. A investigação se dá a partir de cartografias urbanas, fazendo uso de recursos infográficos e sendo divulgado em tempo real por meio de website. Destacamos as principais “paraformalidades” encontradas na maioria das cidades que estudamos: trailers, para-ciclos inventados, para-formal no formal, vendedores isolados móveis e o grandes conjuntos para-formais. Podemos adiantar que é possível compreender que esses equipamentos são parte da cidade e devem ser levados em consideração pelos arquitetos e urbanistas, tanto em novos projetos como em revitalizações arquitetônicas e urbanísticas.The research works towards mapping and profiling the scenes “para-formal” found in the public space of the centers of Latin American cities. We understand “para-formal” as all activities found in the public space of the city that are not part of their urban design (the original), but that “now” part of their daily lives. The research starts from urban cartography, making use of infographics and resources being released in real time via the website. Highlight the main “to-tape” found in most cities we studied: trailers, for-cycles invented, paraformal in the formal, isolated mobile sallers and large ensembles para-formals. We anticipate that it is possible to understand that the equipment is part of the city and should be considered by architects and planners, both in new projects such as in architectural and urban revitalization.Eje 3: Derecho a la ciudad: mutaciones, recomposiciones, adaptaciones, reformulaciones.Facultad de Arquitectura y Urbanism

Descobrindo “para-formalidades”: atividades que gritam por espaço

A pesquisa trabalha no sentido de mapear e dar visibilidade às cenas “para-formais” encontradas no espaço público dos centros de cidades latinoamericanas. Entendemos “para-formal” como todas as atividades encontradas no espaço público da cidade que não fazem parte de seu desenho urbano (original), mas que “agora” fazem parte de seu cotidiano. A investigação se dá a partir de cartografias urbanas, fazendo uso de recursos infográficos e sendo divulgado em tempo real por meio de website. Destacamos as principais “paraformalidades” encontradas na maioria das cidades que estudamos: trailers, para-ciclos inventados, para-formal no formal, vendedores isolados móveis e o grandes conjuntos para-formais. Podemos adiantar que é possível compreender que esses equipamentos são parte da cidade e devem ser levados em consideração pelos arquitetos e urbanistas, tanto em novos projetos como em revitalizações arquitetônicas e urbanísticas.The research works towards mapping and profiling the scenes “para-formal” found in the public space of the centers of Latin American cities. We understand “para-formal” as all activities found in the public space of the city that are not part of their urban design (the original), but that “now” part of their daily lives. The research starts from urban cartography, making use of infographics and resources being released in real time via the website. Highlight the main “to-tape” found in most cities we studied: trailers, for-cycles invented, paraformal in the formal, isolated mobile sallers and large ensembles para-formals. We anticipate that it is possible to understand that the equipment is part of the city and should be considered by architects and planners, both in new projects such as in architectural and urban revitalization.Eje 3: Derecho a la ciudad: mutaciones, recomposiciones, adaptaciones, reformulaciones.Facultad de Arquitectura y Urbanism

Bending and Base-Stacking Interactions in Double-Stranded Semiflexible Polymer

Simple expressions for the bending and the base-stacking energy of double-stranded semiflexible biopolymers (such as DNA and actin) are derived. The distribution of the folding angle between the two strands is obtained by solving a Schr\"{o}dinger equation variationally. Theoretical results based on this model on the extension versus force and extension versus degree of supercoiling relations of DNA chain are in good agreement with the experimental observations of Cluzel {\it et al.} [Science {\bf 271}, 792 (1996)], Smith {\it et al.} [{\it ibid.} {\bf 271}, 795 (1996)], and Strick {\it et al.} [{\it ibid.} {\bf 271}, 1835 (1996)].Comment: 8 pages in Revtex format, with 4 EPS figure

Emissions of Carbonaceous Particulate Matter and Ultrafine Particles from Vehicles-A Scientific Review in a Cross-Cutting Context of Air Pollution and Climate Change

Featured Application Key conclusions and recommendations are proposed to enlighten decision makers in view of the next regulations on vehicle emissions in Europe and worldwide through the synergistic contexts of air quality and climate change. Airborne particulate matter (PM) is a pollutant of concern not only because of its adverse effects on human health but also on visibility and the radiative budget of the atmosphere. PM can be considered as a sum of solid/liquid species covering a wide range of particle sizes with diverse chemical composition. Organic aerosols may be emitted (primary organic aerosols, POA), or formed in the atmosphere following reaction of volatile organic compounds (secondary organic aerosols, SOA), but some of these compounds may partition between the gas and aerosol phases depending upon ambient conditions. This review focuses on carbonaceous PM and gaseous precursors emitted by road traffic, including ultrafine particles (UFP) and polycyclic aromatic hydrocarbons (PAHs) that are clearly linked to the evolution and formation of carbonaceous species. Clearly, the solid fraction of PM has been reduced during the last two decades, with the implementation of after-treatment systems abating approximately 99% of primary solid particle mass concentrations. However, the role of brown carbon and its radiative effect on climate and the generation of ultrafine particles by nucleation of organic vapour during the dilution of the exhaust remain unclear phenomena and will need further investigation. The increasing role of gasoline vehicles on carbonaceous particle emissions and formation is also highlighted, particularly through the chemical and thermodynamic evolution of organic gases and their propensity to produce particles. The remaining carbon-containing particles from brakes, tyres and road wear will still be a problem even in a future of full electrification of the vehicle fleet. Some key conclusions and recommendations are also proposed to support the decision makers in view of the next regulations on vehicle emissions worldwide

Ferromagnetism and giant magnetoresistance in the rare earth fullerides Eu6-xSrxC60

We have studied crystal structure, magnetism and electric transport properties of a europium fulleride Eu6C60 and its Sr-substituted compounds, Eu6-xSrxC60. They have a bcc structure, which is an isostructure of other M6C60 (M represents an alkali atom or an alkaline earth atom). Magnetic measurements revealed that magnetic moment is ascribed to the divalent europium atom with S = 7/2 spin, and a ferromagnetic transition was observed at TC = 10 - 14 K. In Eu6C60, we also confirm the ferromagnetic transition by heat capacity measurement. The striking feature in Eu6-xSrxC60} is very large negative magnetoresistance at low temperature; the resistivity ratio \rho(H = 9 T)/\rho(H = 0 T) reaches almost 10^{-3} at 1 K in Eu6C60. Such large magnetoresistance is the manifestation of a strong pi-f interaction between conduction carriers on C60 and 4f electrons of Eu.Comment: 5 pages, 4 figure