Interannual variability patterns of the world’s total column water content: Amazon River basin     

Isabella Bordi  Roberto De Bonis  Klaus Fraedrich  Alfonso Sutera 《Theoretical and Applied Climatology》2015,122(3-4):441-455

  相似文献   

Fundamental physics and absolute positioning metrology with the MAGIA lunar orbiter     

Simone Dell��Agnello  Caterina Lops  Giovanni O. Delle Monache  Douglas G. Currie  Manuele Martini  Roberto Vittori  Angioletta Coradini  Cesare Dionisio  Marco Garattini  Alessandro Boni  Claudio Cantone  Riccardo March  Giovanni Bellettini  Roberto Tauraso  Mauro Maiello  Luca Porcelli  Simone Berardi  Nicola Intaglietta 《Experimental Astronomy》2011,32(1):19-35

MAGIA is a mission approved by the Italian Space Agency (ASI) for Phase A study. Using a single large-diameter laser retroreflector, a large laser retroreflector array and an atomic clock onboard MAGIA we propose to perform several fundamental physics and absolute positioning metrology experiments: VESPUCCI, an improved test of the gravitational redshift in the Earth?CMoon system predicted by General Relativity; MoonLIGHT-P, a precursor test of a second generation Lunar Laser Ranging (LLR) payload for precision gravity and lunar science measurements under development for NASA, ASI and robotic missions of the proposed International Lunar Network (ILN); Selenocenter (the center of mass of the Moon), the determination of the position of the Moon center of mass with respect to the International Terrestrial Reference Frame/System (ITRF/ITRS); this will be compared to the one from Apollo and Lunokhod retroreflectors on the surface; MapRef, the absolute referencing of MAGIA??s lunar altimetry, gravity and geochemical maps with respect to the ITRF/ITRS. The absolute positioning of MAGIA will be achieved thanks to: (1) the laboratory characterization of the retroreflector performance at INFN-LNF; (2) the precision tracking by the International Laser Ranging Service (ILRS), which gives two fundamental contributions to the ITRF/ITRS, i.e. the metrological definition of the geocenter (the Earth center of mass) and of the scale of length; (3) the radio science and accelerometer payloads; (4) support by the ASI Space Geodesy Center in Matera, Italy. Future ILN geodetic nodes equipped with MoonLIGHT and the Apollo/Lunokhod retroreflectors will become the first realization of the International Moon Reference Frame (IMRF), the lunar analog of the ITRF.  相似文献   

Retraction notice to “On radial pulsations in relativistic stars” [Astropart. Phys. 26 (2006) 64-67]     

Roberto Aquilano 《Astroparticle Physics》2011,35(1):39

  相似文献   

Retraction notice to “On the nature of relativistic stars” [Astropart. Phys. 32 (2009) 153-159]     

Silvia Morales  Alejandra Zorzi  Roberto Aquilano 《Astroparticle Physics》2011,35(1):40

  相似文献   

An in-depth look at the lunar crater Copernicus: Exposed mineralogy by high-resolution near-infrared spectroscopy     

Roberto Bugiolacchi  Urs Mall  Susan McKenna-Lawlor  Kjell Brønstad  Finn Søraas  Rolf B. Pedersen 《Icarus》2011,213(1):43-63

Newly acquired, sequentially spaced, high-resolution near-infrared spectra across the central section of crater Copernicus’ interior have been analyzed using a range of complementary techniques and indexes.We have developed a new interpretative method based on a multiple stage normalization process that appears to both confirm and expand on previous mineralogical estimations and mapping. In broad terms, the interpreted distribution of the principle mafic species suggests an overall composition of surface materials dominated by calcium-poor pyroxenes and minor olivine but with notable exceptions: the southern rim displays strong ca-rich pyroxene absorption features and five other locations, the uppermost northern crater wall, opposite rim sections facing the crater floor, and the central peak Pk1 and at the foot of Pk3, show instead strong olivine signatures.We also propose impact glass an alternative interpretation to the source of the weak but widespread olivine-like spectral signature found in low-reflectance samples, since it probably represents a major regolith constituent and component in large craters such as Copernicus.The high quality and performance of the SIR-2 data allows for the detection of diagnostic key mineral species even when investigating spectral samples with very subdued absorption features, confirming the intrinsic high-quality value of the returned data.  相似文献   

Particulate organic matter uptake rates of two benthic filter-feeders (Sabella spallanzanii and Branchiomma luctuosum) candidates for the clarification of aquaculture wastewaters     

Cavallo D  Pusceddu A  Danovaro R  Giangrande A 《Marine pollution bulletin》2007,54(5):622-625

  相似文献   

Sulphate reduction in the sediment of the Venice canals (Italy)     

Zaggia L  Rosso J  Zonta R 《Marine pollution bulletin》2007,55(10-12):415-424

The sulphur cycle in the sediment of the Venice canal network was investigated by considering the sulphate reduction rate (SRR) and the distribution of sulphur compounds, in both pore water and sediment. Sulphate reduction (SR) is the main process in the metabolism of the organic matter supplied to the network by untreated urban effluents. Although it might account for the decomposition of only a limited percentage of the total organic-C inputs, the estimated rates are among the highest observed in coastal sediments. Measured rates range from 0.26 to 0.99 micromolcm(-3)d(-1), while mean annual values, estimated by a diagenetic model, vary from 0.16 to 0.43 micromolcm(-3)d(-1). The speciation of S in the sediment reveals that pyrite-S is the most abundant component of the total reduced S pool, whereas acid volatile sulphides and elemental sulphur together account for less than 45%. A preliminary budget indicates that the rate of burial of solid-phase S is small compared to the S produced by SR (from 10 to 25%). A large amount of reduced S is then lost from the canal deposits to be re-oxidised at the sediment-water interface or in the overlying water column.  相似文献   

Measuring and managing changes in estuaries and lagoons: morphological and eco-toxicological aspects   总被引：1，自引：0，他引：1  

Zonta R  Guerzoni S  Pérez-Ruzafa A  de Jonge VN 《Marine pollution bulletin》2007,55(10-12):403-406

  相似文献   

N and O isotope effects during nitrate assimilation by unicellular prokaryotic and eukaryotic plankton cultures   总被引：4，自引：0，他引：4  

J. Granger  D.M. Sigman  M.T. Maldonado 《Geochimica et cosmochimica acta》2010,74(3):1030-1040

In order to provide biological systematics from which to interpret nitrogen (N) and oxygen (O) isotope ratios of nitrate (¹⁵N/¹⁴N, ¹⁸O/¹⁶O, respectively) in the environment, we previously investigated the isotopic fractionation of nitrate during its assimilation by mono-cultures of eukaryotic algae (Granger et al., 2004). In this study, we extended our analysis to investigate nitrate assimilation by strains of prokaryotic plankton. We measured the N and O isotope effects, ¹⁵ε and ¹⁸ε, during nitrate consumption by cultures of prokaryotic strains and by additional eukaryotic phytoplankton strains (where ε is the ratio of reaction rate constants of the light vs. heavy isotopologues, ^lightk and ^heavyk; ε = ^lightk/^heavyk − 1 × 1000, expressed in per mil). The observed ¹⁵ε ranged from 5‰ to 8‰ among eukaryotes, whereas it did not exceed 5‰ for three cyanobacterial strains, and was as low as 0.4‰ for a heterotrophic α-protoeobacterium. Eukaryotic phytoplankton fractionated the N and O isotopes of nitrate to the same extent (i.e., ¹⁸ε ∼ ¹⁵ε). The ¹⁸ε:¹⁵ε among the cyanobacteria was also ∼1, whereas the heterotrophic α-proteobacterial strain, which showed the lowest ¹⁵ε, between 0.4‰ and 1‰, had a distinct ¹⁸ε:¹⁵ε of ∼2, unlike any plankton strain observed previously. Equivalent N vs. O isotope discrimination is thought to occur during internal nitrate reduction by nitrate reductase, such that the cellular efflux of the fractionated nitrate into the medium drives the typically observed ¹⁸ε:¹⁵ε of ∼1. We hypothesize that the higher in the ¹⁸ε:¹⁵ε of the α-proteobacterium may result from isotope discrimination by nitrate transport, which is evident only at low amplitude of ε. These observations warrant investigating whether heterotrophic bacterial assimilation of nitrate decreases the community isotope effects at the surface ocean.  相似文献   

Alpine tectonics in the Calabrian–Peloritan belt (southern Italy): New 40Ar/39Ar data in the Aspromonte Massif area     

Thomas Heymes  Patrick Monié  Nicolas Arnaud  Arnaud Pêcher  Jean-Pierre Bouillin  Roberto Compagnoni 《Lithos》2010,114(3-4):451-472

This study provides new ⁴⁰Ar/³⁹Ar geochronological constraints on the age of the Alpine tectonics in the Aspromonte Massif (southern part of the Calabrian–Peloritan belt). This massif exposes the upper units of the Calabride Complex which originated from the European continental margin. The Calabride Complex was incorporated in the Alpine orogenic wedge and then integrated into the Apennines and Maghrebides fold-and-thrust belts. Throughout the Calabride Complex there is evidence for a two stage tectonic history, which remains however rather poorly dated: Alpine nappe stacking is followed by extensional reworking along the former thrust contacts or along new detachment surfaces. Our new ages suggest that exhumation of the uppermost units, which accompanied nappe stacking, probably started at 45 Ma and that the deepest units were almost completely exhumed at 33 Ma. This kinematics probably corresponds to syn-orogenic extension while the end of exhumation is clearly related to the extensional tectonics dated at 28.6 Ma along detachment structures.Our geochronological data reveal a very short lag time between accretional and extensional processes in this part of the Mediterranean Alpine orogenic belt. The direction of extension, when the units are restored to their initial position (i.e. before the opening of the Western Mediterranean basins and the bending of the arc) is NNE–SSW. Such a direction does not fit with the eastward slab-retreat model generally put forward to explain extension in the Western Mediterranean. In contrast, we provide evidence for roughly N–S middle Oligocene extension in the accretionary prism, not previously described in this part of the Mediterranean domain.  相似文献