A local-scale approach to estuarine flood risk management   总被引：1，自引：0，他引：1  

Paula Freire  Alexandre O. Tavares  Luís Sá  Anabela Oliveira  André B. Fortunato  Pedro P. dos Santos  Ana Rilo  João L. Gomes  João Rogeiro  Rui Pablo  Pedro J. Pinto 《Natural Hazards》2016,84(3):1705-1739

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Alpine thermal events in the central Serbo-Macedonian Massif (southeastern Serbia)     

Milorad D. Antić  Alexandre Kounov  Branislav Trivić  Andreas Wetzel  Irena Peytcheva  Albrecht von Quadt 《International Journal of Earth Sciences》2016,105(5):1485-1505

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Defining the Potential of Nanoscale Re‐Os Isotope Systematics Using Atom Probe Microscopy          下载免费PDF全文

Luke Daly  Phil A. Bland  Svetlana Tessalina  David W. Saxey  Steven M. Reddy  Denis Fougerouse  William D.A. Rickard  Lucy V. Forman  Alexandre La Fontaine  Julie M. Cairney  Simon P. Ringer  Bruce F. Schaefer  Daniel Schwander 《Geostandards and Geoanalytical Research》2018,42(3):279-299

Atom probe microscopy (APM) is a relatively new in situ tool for measuring isotope fractions from nanoscale volumes (< 0.01 μm³). We calculate the theoretical detectable difference of an isotope ratio measurement result from APM using counting statistics of a hypothetical data set to be ± 4δ or 0.4% (2s). However, challenges associated with APM measurements (e.g., peak ranging, hydride formation and isobaric interferences), result in larger uncertainties if not properly accounted for. We evaluate these factors for Re‐Os isotope ratio measurements by comparing APM and negative thermal ionisation mass spectrometry (N‐TIMS) measurement results of pure Os, pure Re, and two synthetic Re‐Os‐bearing alloys from Schwander et al. (2015, Meteoritics and Planetary Science, 50, 893) [the original metal alloy (HSE) and alloys produced by heating HSE within silicate liquid (SYN)]. From this, we propose a current best practice for APM Re‐Os isotope ratio measurements. Using this refined approach, mean APM and N‐TIMS ¹⁸⁷Os/¹⁸⁹Os measurement results agree within 0.05% and 2s (pure Os), 0.6–2% and 2s (SYN) and 5–10% (HSE). The good agreement of N‐TIMS and APM ¹⁸⁷Os/¹⁸⁹Os measurements confirms that APM can extract robust isotope ratios. Therefore, this approach permits nanoscale isotope measurements of Os‐bearing alloys using the Re‐Os geochronometer that could not be measured by conventional measurement principles.  相似文献   

Physicochemical properties of fine aerosols at Plan d'Aups during ESCOMPTE     

Angela Marinoni  Paolo Laj  Pierre Alexandre Deveau  Federica Marino  Grazia Ghermandi  Fabien Aulagnier  Hlne Cachier 《Atmospheric Research》2005,74(1-4):565-580

The physical and chemical properties of aerosol particles were investigated at Plan d'Aups, one of the ESCOMPTE sites located in the St. Baume mountain area (700 m a.s.l.), 50 km east of Marseilles (France). The site is ideally located for assessing the vertical and horizontal extent of the pollution plume from the Marseilles–Berre area.Our study showed that polluted air masses from the Marseilles–Berre area are advected to Plan d'Aups in the early afternoon. Average daily concentration of particles reaches up to 40 μg m⁻³ while 1-h average particle number concentration is greater than 30,000 cm⁻³. Most of the particle mass is composed of SO₄²⁻ and organic carbon (OC). The chemical properties of the particles revealed that an additional source, possibly from the industrial area of Gardanne, contributes to the aerosol mass. This last source is characterised by significant emissions of elements, such as Zn, V, Al and Si.In addition to transport, we found that gas-to-particle conversion takes place at the interface between the free troposphere and the boundary layer. We estimated that on average, 30% of the particle number is accounted for by direct nucleation. This is potentially a major aerosol source to the free troposphere.  相似文献   

Long-term evolution of the spin of Venus: II. numerical simulations     

Alexandre C.M. Correia  Jacques Laskar 《Icarus》2003,163(1):24-45

We present here the numerical application of the theoretical results derived in Correia et al. (2003, Icarus 163, 1-23) for the spin evolution of Venus since its formation. We explore a large variety of initial conditions to cover the possible formation and evolutionary scenarios. In particular, we pay special attention to the evolutions which cross the chaotic zone resulting from secular planetary perturbations (Laskar and Robutel, 1993, Nature 361, 608-612). We demonstrate that Venus’ axis can be temporarily trapped in a secular resonance with the node of Neptune’s orbit, which can prevent it from being tilted to 180° and will drive it toward 0°. We test several dissipation models and parameters to evaluate their contribution to the planet’s spin history. We confirm that despite the variations in the models, only three of the four final spin states of Venus are possible (Correia and Laskar, 2001, Nature 411, 767-770) and that the present observed retrograde spin state of Venus can be attained by two different processes. In the first scenario (π−), the axis is tilted toward 180° while its rotation rate slows down, while in the second one, the axis is driven toward 0° obliquity and the rotation rate decreases, stops, and increases again in the reverse direction to a final equilibrium value (0−).  相似文献   

Pore scale modeling of immiscible and miscible fluid flows using smoothed particle hydrodynamics     

Alexandre M. Tartakovsky  Paul Meakin 《Advances in water resources》2006

A numerical model based on smoothed particle hydrodynamics (SPH) was developed and used to simulate immiscible and miscible fluid flows in porous media and to study effects of pore scale heterogeneity and anisotropy on such flows.  相似文献   

Occurrence and Resistance of Pathogenic Bacteria Along the Tietê River Downstream of São Paulo in Brazil     

Wolf-Rainer Abraham  Alexandre José Macedo  Luiz Humberto Gomes  Flavio C. A. Tavares 《洁净——土壤、空气、水》2007,35(4):339-347

The load of pathogenic bacteria, their fate and their dangerousness in the Tietê River were assessed along 100 km starting from the city of São Paulo, Brazil. The data were compared with those from two German rivers. High loads of pathogens were found in the Tietê River near the city of São Paulo (Escherichia coli O157:H7, Shigella flexneri, and Shigella boydii), which were absent 30 km downstream of São Paulo. The antibiotic resistances observed in the Tietê river were rather low and decreased after the major input in São Paulo to significantly lower levels about 30 km downstream. While the Brazilian isolates were more susceptible for ampicillin than the German ones, the reverse was observed for gentamycin. For optimal control of infections in humans critical areas where these bacteria survived longer and their elimination mechanisms should be identified as well as the extent and the origin of antibiotic resistance should be determined.  相似文献   

Electron-impact rotational and hyperfine excitation of HCN, HNC, DCN and DNC     

Alexandre Faure  Hemal N. Varambhia  Thierry Stoecklin  Jonathan Tennyson 《Monthly notices of the Royal Astronomical Society》2007,382(2):840-848

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Slope-control on the aspect ratio of river basins     

Sébastien Castelltort  Guy Simpson  Alexandre Darrioulat 《地学学报》2009,21(4):265-270

Although it is traditionally thought that drainage basins are geometrically similar, we present new results which indicate that the aspect ratio of weakly dissected river basins at large scales (10–10³ km²) depends on the surface slope: steeper surfaces develop narrower and lengthier basins whereas more gently dipping surfaces develop more equant and wider basins. This relationship is interpreted to be related to the nature of water flow over rough surfaces, with steeper slopes causing less flow convergence and lengthier and narrower basins. We derive an empirical relationship that can be used to infer the slope of a surface on which a river basin acquired its geometry based solely on a measure of its basin form. This relation provides a unique means of inferring the relative chronology of river basin development with respect to surface tilting and therefore provides a direct link between river basin morphology and tectonics.  相似文献   

Molecular and distribution data on the poorly known,elusive, cave mysid Harmelinella mariannae (Crustacea: Mysida)          下载免费PDF全文

Pierre Chevaldonné  Pierre‐Alexandre Rastorgueff  Defne Arslan  Christophe Lejeusne 《Marine Ecology》2015,36(3):305-317

Mediterranean underwater marine caves harbour abundant populations of several species of mysids that are increasingly used as biological models in ecological and evolutionary studies. One exception is the species Harmelinella mariannae, described in 1989 and then hardly ever again reported in the literature. We here provide the first data on the distribution of this poorly known taxon that, contrary to expectations for a rare brooding cave dweller, we now report from Madeira Island in the nearby Atlantic, to the easternmost parts of the Mediterranean. Brief behavioural observations are added, particularly its atypical solitary habits and its feeding behaviour as a high trophic level carnivore. Molecular characterization of the different specimens captured provided three sorts of information. Mitochondrial COI and 16S haplotypes suggest different colonization waves in the Mediterranean, with one group in the Eastern Basin, two in the Marseille region in the NW part of this sea, and another group with a very wide extension from Madeira to Liguria and Malta. Mitochondrial data also support that one of the groups in Marseille might have diverged as a cryptic species of Harmelinella. 18S rRNA gene displays a single common sequence to all specimens from the four groups, and seems to confirm the original proposed placement of this taxon within the subfamily Heteromysinae, not Leptomysinae.  相似文献