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31.
M. Cristina Fossi Silvia Casini Letizia Marsili Stefania Ancora Gabriele Mori Giovanni Neri Teresa Romeo Antonella Ausili 《Marine environmental research》2004,58(2-5):425
In this project we investigated the ecotoxicological effects of endocrine disrupters in a four-year survey of the Mediterranean population of swordfish (Xiphias gladius). In the Mediterranean environment, top predators, such as swordfish, accumulate high concentrations of polyhalogenated aromatic hydrocarbons (PHAHs) and toxic metals, potentially incurring high toxicological risk. The effects of organochlorines and trace elements (Hg, Cd and Pb) in 192 swordfish specimens, caught in the Strait of Messina, Sicily, Italy, were investigated using vitellogenin (Vtg), zona radiata proteins (Zrp) and CYP1A (BPMO, EROD) activities. Vtg and Zrp were found to be dramatically induced in some adult male specimens, suggesting that this species is highly exposed to estrogens in the Mediterranean Sea. A role of organochlorines in this induction phenomenon is suggested by the statistically significant correlations between Zrp in plasma and PCB concentrations in muscle (p<0.032) and Vtg in plasma and PCB concentrations in liver (p<0.034) of male specimens. Levels of trace elements in liver were in the following ranges: Hg 1–22, Cd 1–28 and Pb 0–1.6 ppm d.w. These data indicate potential reproductive alterations in large pelagic fish and suggest the need for continuous monitoring to avoid reductions in the population of this fish species of high commercial and ecological interest. 相似文献
32.
Rosanna Sordo Antonella Vallenari Rosaria Tantalo France Allard Ronny Blomme Jean-Claud Bouret Ines Brott Yves Fremat Christophe Martayan Yassine Damerdji Bengt Edvardsson Eric Josselin Bertrand Plez Oleg Kochukhov Mary Kontizas Ulisse Munari Tenay Saguner Jean Zorec Andreas Schweitzer Paraskevi Tsalmantza 《Astrophysics and Space Science》2010,328(1-2):331-335
ESA’s Gaia mission will collect low resolution spectroscopy in the optical range for ~109 objects. Complete and up-to-date libraries of synthetic stellar spectra are needed to built algorithms aimed to automatically derive the classification and the parametrization of this huge amount of data. In addition, libraries of stellar spectra are one of the main ingredients of stellar population synthesis models, aiming to derive the properties of unresolved stellar populations from their integrated light. We present (a) the newly computed libraries of synthetic spectra built by the Gaia community, covering the whole optical range (300–1100 nm) at medium-high resolution of (0.3 nm) for stars spanning the most different types, from M to O, from A-peculiar to Emission lines to White Dwarfs, and (b) the implementation of those libraries in our SSP code (Tantalo in The Initial Mass Function 50 Years Later, 327:235 2005), exploring different stellar evolution models. 相似文献
33.
This paper presents a new depth to acoustic basement map based on a grid of seismic profiles. In the Western Alboran Basin the basement is more than 10 km deep. An examination of a seismic profile of this region suggests that Late Oligocene–Early Miocene 5 km thick synrift formation has been accumulated in this basin. This West Alboran basin has been formed in an extensional setting, but in a fore‐arc position, south of the Balearic Islands then westwards transported behind a subduction zone. 相似文献
34.
E. Bonatti M. Sarnthein A. Boersma M. Gorini J. Honnorez 《Earth and Planetary Science Letters》1977,35(3):369-383
Partly phosphatized, oolitic-biogenic limestones were recovered 950–1300 m below sea level from two sites near the crest of a transverse ridge running parallel and adjacent to the Romanche fracture valley (equatorial Atlantic). Some of the biogenic contituents of the limestones (the benthonic foraminiferal genusAmphistegina; corals of the genusStylophora sp., scaphopods, etc.); their paleofacies assemblage (including echinoderms, gastropods, calcareous algae, etc.); and the presence of a well-developed oolitic facies, indicate that the limestones formed in very shallow water close to sea level. In addition, several features of the limestones (including the presence of stromatolite-like laminae, and dissolution features typical of subaerial diagenesis) suggest that the summit of the transverse ridge might have undergone episodes of emersion. The limestones were formed on a shallow carbonate bank at around the Miocene-Pliocene boundary, i.e., 5 ± 1 Myr ago, as determined by the age of fossil planktonic foraminifera and corals. The transverse ridge must have subsided since that time at an average rate of 0.2 mm/yr. It is unlikely that the vertical motions of the Romanche transverse crustal block were caused solely by accreting plate margin- or mantle plume-related volcanic and/or tectonic processes. It is suggested instead that such motions are related to vertical tectonism typical of large oceanic fracture zones. 相似文献
35.
36.
Giovanni De Giudici Antonella Rossi Pierfranco Lattanzi 《Geochimica et cosmochimica acta》2005,69(9):2321-2331
This work describes a laboratory investigation of processes ruling the dissolution of galena (PbS) under conditions that mimic oxidising Earth surface environments. Freshly cleaved (001) galena surface was partially dissolved in solutions at different pH (HCl, pH between 1.2 and 5.8) and temperature (298 K) levels for several weeks in a flow-through reactor. Analysis of the galena surface after exposure to oxygen-saturated solutions was performed by XPS. The estimated thickness of surface layer formed after interaction for four weeks with solution at pH 5.8 was ∼0.5 nm. After the same time of interaction with solution at pH 1, the surface layer was at least 9 nm thick. Stationary dissolution rates were measured at different pH (between 1 and 5.8) and temperatures (298, 323, 348 K). Reaction order with respect to hydrogen ion averages 0.6 and slightly decreases with temperature. Dissolution rates, plotted vs. the reciprocal values of temperature, follow Arrhenius behaviour. Activation energies show a sharply discontinuous variation with pH. They are 13.5 ± 2 kJmol−1 at pH = 1.2 and 2.87, whereas at pH of 4.08, 4.7, and 5.8, they show, respectively, values of 48.8 ± 3.5, 45 ± 4, and 51 ± 4 kJmol−1. The apparent activation energy was also investigated by starting the experiment from pH 5.8 and then decreasing to pH 1.2. In this case, the apparent activation energies were 44 ± 4 kJmol−1 and 21 ± 4 kJmol−1, respectively.Apparent activation energies indicate a diffusion-controlled kinetic regime for pH <3, and a mixture of surface and diffusion control for pH between ∼4 and 5.8. A strong effect of solution pH on the mineral-water interface is revealed also by the observed pH dependence of surface-layer thickness. On the basis of the high-resolution XPS signals, the dependence of activation energies on solution pH should reflect a change of structure, and also chemical composition, of the mineral-water interface. 相似文献
37.
Aldo Zollo Antonella Bobbio Antonio Emolo André Herrero Giuseppe De Natale 《Journal of Seismology》1997,1(4):305-319
A mixed statistical-deterministic model of earthquake rupture is developed for evaluating the strong ground motion in the near source range (receiver distance comparable to the fault length). The source parametrization is based on the k-square model and the propagation is computed by asymptotic Green's functions. The method is applied to the case of 1976, Friuli earthquake (M = 6.5) in northern Italy which occurred on a low-dip thrusting fault. Acceleration records at 29 stations are computed for 100 simulations of rupture histories. The mean value map of peak ground accelerations shows clearly a maximum to the south due to the inner geometry and directivity of the source. The variation of the estimated PGA versus the epicentral distance is strongly dependent on azimuth and is not decreasing monotonically. The comparison of these curves with those predicted by empirical acceleration–distance relationships shows discrepancies in the near source distance range. This study shows the importance of considering the complexity of the source rupture process for strong motion estimate in the near source range. 相似文献
38.
Antonio Tadeu dos Reis Christian Gorini Alain Mauffret Wiktor Weibull 《Comptes Rendus Geoscience》2004,336(2):143-150
The Marseilles (also called Marseilles/Planier) and Grand Rhone sedimentary ridges, offshore the Gulf of Lions, western Mediterranean Sea, are generated by sediment spillover funnelled by the Marseilles and Grand-Rhone canyons, respectively. We show that the Marseilles and Grand-Rhone canyon directions are tectonically conditioned by Plio-Quaternary salt-induced sea-floor relief. Overburden extension in the area created an assemblage of listric faults running parallel to the strike of the continental margin. This salt-induced topography resulted in accentuated fault scarps impacting the sea-floor morphology and forcing submarine valleys to deflect to the east. Gravity-induced extension equally influenced the morphological pattern of the valley overbanking deposits. Sediment spillover occurred on both flanks of the canyons, but because active faulting generated space accommodation for overflow deposits, it inhibited the development of typical levee morphology along the canyons' left flanks. To cite this article: A.T. dos Reis, C. R. Geoscience 336 (2004). 相似文献
39.
Lahcen Zouhri Christian Gorini Christian Lamouroux Daniel Vachard Mohammed Dakki 《Comptes Rendus Geoscience》2003,335(3):319-326
The aquifer of the Rharb Basin is constituted by heterogeneous material. The seismic reflexion interpretation carried out in this area, highlighted a permeable device compartmentalized in raised and subsided blocks. Depressions identified in the northern and southernmost zones are characterized by Plio-Quaternary fillings that are favourable to the hydrogeological exploitation. Two mechanisms contribute to structure the Plio-Quaternary aquifer: the Hercynian reactivation in the southernmost part, and the gravitational mechanism of the Pre-Rifean nappe. The groundwater flow and the aquifer thickening are controlled by this reactivation. 相似文献
40.
Imtiyaz A. Parvez Andrea Magrin Franco Vaccari Ashish Ramees R. Mir Antonella Peresan Giuliano Francesco Panza 《Journal of Seismology》2017,21(6):1559-1575
Current computational resources and physical knowledge of the seismic wave generation and propagation processes allow for reliable numerical and analytical models of waveform generation and propagation. From the simulation of ground motion, it is easy to extract the desired earthquake hazard parameters. Accordingly, a scenario-based approach to seismic hazard assessment has been developed, namely the neo-deterministic seismic hazard assessment (NDSHA), which allows for a wide range of possible seismic sources to be used in the definition of reliable scenarios by means of realistic waveforms modelling. Such reliable and comprehensive characterization of expected earthquake ground motion is essential to improve building codes, particularly for the protection of critical infrastructures and for land use planning. Parvez et al. (Geophys J Int 155:489–508, 2003) published the first ever neo-deterministic seismic hazard map of India by computing synthetic seismograms with input data set consisting of structural models, seismogenic zones, focal mechanisms and earthquake catalogues. As described in Panza et al. (Adv Geophys 53:93–165, 2012), the NDSHA methodology evolved with respect to the original formulation used by Parvez et al. (Geophys J Int 155:489–508, 2003): the computer codes were improved to better fit the need of producing realistic ground shaking maps and ground shaking scenarios, at different scale levels, exploiting the most significant pertinent progresses in data acquisition and modelling. Accordingly, the present study supplies a revised NDSHA map for India. The seismic hazard, expressed in terms of maximum displacement (Dmax), maximum velocity (Vmax) and design ground acceleration (DGA), has been extracted from the synthetic signals and mapped on a regular grid over the studied territory. 相似文献