Passive acoustic recording of Ophidion rochei calling activity in Calvi Bay (France)          下载免费PDF全文

Loïc Kéver  Pierre Lejeune  Loïc N. Michel  Eric Parmentier 《Marine Ecology》2016,37(6):1315-1324

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Nickel dispersion and enrichment at the bottom of the regolith: formation of pimelite target-like ores in rock block joints (Koniambo Ni deposit,New Caledonia)     

Michel Cathelineau  Benoît Quesnel  Pierre Gautier  Philippe Boulvais  Clément Couteau  Maxime Drouillet 《Mineralium Deposita》2016,51(2):271-282

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Radio study of X-ray clusters of galaxies — I. A3528: a pre-merging cluster in the core of the Shapley Supercluster     

A. D. Reid  R. W. Hunstead  & M. M. Pierre 《Monthly notices of the Royal Astronomical Society》1998,296(3):531-544

As part of an extensive radio–IR–optical–X-ray study of ROSAT clusters of galaxies in the Hydra region we have observed the bimodal Abell cluster A3528, located in the core of the Shapley Supercluster ( z  ≃ 0.053), with the Molonglo Observatory Synthesis Telescope at 843 MHz and the Australia Telescope Compact Array at 1.4 and 2.4 GHz. This is part I in a series of papers which looks at the relationship between the radio and X-ray emission in samples of ROSAT selected clusters.   The radio source characteristics — tailed morphologies and steep spectra — are consistent with the effects of a dense intracluster medium and the pre-merging environment of A3528. In particular, we present evidence that the minor member of the radio-loud dumbbell galaxy located at the centre of the northern component of A3528 is on a plunging orbit. We speculate that this orbit may have been induced by the tidal interactions between the merging components of A3528. In addition, the radio source associated with the dominant member of the dumbbell galaxy exhibits many of the characteristics of compact steep spectrum sources. We argue that the radio emission from this source was triggered ∼ 10⁶ yr ago by tidal interactions between the two members of the dumbbell galaxy, strengthening the argument that compact steep spectrum (CSS) sources are young.   Re-analysis of archive pointed Position Sensitive Proportional Counter (PSPC) data using multiresolution filtering suggests the presence of an AGN and/or a cooling flow in the southern component of A3528.  相似文献   

Detection of underground cavities with monofrequency electromagnetic tomography between boreholes in the frequency range 100 MHz to 1 GHz1     

Philippe C&#x;te  Pierre Degauque  Richard Lagabrielle  Nathalie Levent 《Geophysical Prospecting》1995,43(8):1083-1107

In order to detect underground cavities, we have designed a geophysical method based on the interaction of a monochromatic electromagnetic wave in the frequency band 100 MHz to 1 GHz with the ground situated between two boreholes. Three different approaches are involved in the design of this EM tomographic method.

• 1 The application of an ‘exact’ theory is used to calculate artificial data, based on an integral equation method. These data are inverted using a tomographic algorithm whose basic assumptions are rather coarse. The results show that, however, cavities can very well be detected and their position recovered.
• 2 Data are obtained with a physical reduced-scale model in a water tank, in which all parameters are known in advance. The inversion process confirms the validity of the method.
• 3 Underground cavities are actually detected.

The above approaches are described and discussed and results are shown. The equipment involved and its operation is quite simple: the surface devices are commercially available and only the transmitter and receiver antennae must be specially built. The method is shown to be quite efficient and its cost should be reasonably low.  相似文献   

Nitrogen compound emission from biomass burning in tropical African savanna FOS/DECAFE 1991 experiment (Lamto,Ivory Coast)     

Robert Delmas  Jean Pierre Lacaux  Jean Claude Menaut  Luc Abbadie  Xavier Le Roux  Gunter Helas  Jurgen Lobert 《Journal of Atmospheric Chemistry》1995,22(1-2):175-193

Gaseous nitrogen compounds (NO _x , NO _y , NH₃, N₂O) were measured at ground level in smoke plumes of prescribed savanna fires in Lamto, in the southern Ivory Coast, during the FOS/DECAFE experiment in January 1991. During the flaming phase, the linear regression between [NO _x ] and [CO₂] (differences in concentration between smoke plumes and atmosheric background) results volumic emission ratio [NO _x ]/[CO₂]=1.37×10^–3 with only slight differences between heading and backing fires. Nearly 90% of the nitrogen oxides are emitted as NO. Average emission ratios of other compounds are: 1.91, 0.047, and 0.145×10^–3 for NO _y , NH₃ and N₂O, respectively. The emission ratios obtained during this field experiment are compred with corresponding values measured during former experiments with the same plant species in combustion chambers. An accurate determination of both the biomass actually burned and of the plant nitrogen content, allows an assessment of emission fluxes of N-compounds from Guinean savanna burns. Preliminary results dealing with the influence of fire on biogenic emissions from soils are also reported.  相似文献   

Seasonal dynamics of nutrient and biofilm in interstitial habitats of two contrasting riffles in a regulated large river   总被引：3，自引：0，他引：3  

Cécile Claret  Pierre Marmonier  Jean-Paul Bravard 《Aquatic Sciences - Research Across Boundaries》1998,60(1):33-55

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An overview of the mink study     

Pierre R. Crosson  Norman J. Rosenberg 《Climatic change》1993,24(1-2):159-173

Highlights of the previous papers in this series are reviewed. Methodology developed for the MINK study has improved the ability of impacts analysis to deal with questions of (1) spatial and temporal variability in climate change; (2) CO₂-enrichment effects; (3) the reactions of complex enterprises (farms and forests) to climate change and their ability to adjust and adapt; and (4) integrated effects on current and, more particularly, on future regional economies. The methodology also provides for systematic study of adjustment and adaptation opportunities and of the inter-industry linkages that determine what the overall impacts on the regional economy might be. The analysis shows that with a 1930s dust bowl climate the region-wide economic impacts would be small, after adjustments in affected sectors. In this final paper we consider whether synergistic effects among sectoral impacts and more severe climate change scenarios might alter this conclusion. The MINK analysis, as is, leads to the conclusion that a strong research capacity will be required to ensure that technologies facilitating adaptation to climate change will be available when needed. The capacity to deal with climate change also requires an open economy allowing for free trade and movement of people and for institutions that protect unpriced environmental values. More severe climate scenarios and negative synergisms can only strengthen these conclusions.  相似文献   

Global acceleration of lake sediment accumulation rates associated with recent human population growth and land-use changes     

Baud  Alexandre  Jenny  Jean-Philippe  Francus  Pierre  Gregory-Eaves  Irene 《Journal of Paleolimnology》2021,66(4):453-467

Journal of Paleolimnology - Sediment Accumulation Rate (SAR; measured as mm yr?1) and Mass Accumulation Rate (MAR; measured as g cm?2 yr?1) data were collected from...  相似文献   

Kriging and Semivariogram Deconvolution in the Presence of Irregular Geographical Units     

Pierre Goovaerts 《Mathematical Geosciences》2008,40(1):101-128

This paper presents a methodology to conduct geostatistical variography and interpolation on areal data measured over geographical units (or blocks) with different sizes and shapes, while accounting for heterogeneous weight or kernel functions within those units. The deconvolution method is iterative and seeks the point-support model that minimizes the difference between the theoretically regularized semivariogram model and the model fitted to areal data. This model is then used in area-to-point (ATP) kriging to map the spatial distribution of the attribute of interest within each geographical unit. The coherence constraint ensures that the weighted average of kriged estimates equals the areal datum.This approach is illustrated using health data (cancer rates aggregated at the county level) and population density surface as a kernel function. Simulations are conducted over two regions with contrasting county geographies: the state of Indiana and four states in the Western United States. In both regions, the deconvolution approach yields a point support semivariogram model that is reasonably close to the semivariogram of simulated point values. The use of this model in ATP kriging yields a more accurate prediction than a naïve point kriging of areal data that simply collapses each county into its geographic centroid. ATP kriging reduces the smoothing effect and is robust with respect to small differences in the point support semivariogram model. Important features of the point-support semivariogram, such as the nugget effect, can never be fully validated from areal data. The user may want to narrow down the set of solutions based on his knowledge of the phenomenon (e.g., set the nugget effect to zero). The approach presented avoids the visual bias associated with the interpretation of choropleth maps and should facilitate the analysis of relationships between variables measured over different spatial supports.  相似文献   

Conditional Wavelet Technique Applied to Aircraft Data Measured in the Thermal Internal Boundary Layer During Sea-Breeze Events     

Jean-Luc Attié  Pierre Durand 《Boundary-Layer Meteorology》2003,106(3):359-382

We describe a wavelet-based technique to determine the spectral turbulentcontribution to the vertical flux of sensible heat in a position-wavelength representation. This technique combines awavelet transform (Morlet wavelet) with conditional sampling. We apply this methodto aircraft datacollected during a sea-breeze circulation (BEMA97 experiment) with heterogeneousturbulence conditions horizontally and vertically as well. The turbulent fluxes are analysed with the conditional wavelet techniqueas a function of the wavelength and the horizontal distance.The turbulent processes within the thermal internal boundary layer associatedwith the sea breeze are clearly identified. The results exhibit the wavelength bands through which the upward flux (originating fromthe surface) and the downward flux (originating from the top of theboundary layer) are important.  相似文献