Evaluation of ecotoxicological effects of endocrine disrupters during a four-year survey of the Mediterranean population of swordfish (Xiphias gladius)

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.     

Evaluation of ecotoxicological effects of endocrine disrupters during a four-year survey of the Mediterranean population of swordfish (Xiphias gladius)

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.     

On the jet contribution to the active galactic nuclei cosmic energy budget

Black holes release energy via the production of photons in their accretion discs but also via the acceleration of jets. We investigate the relative importance of these two paths over cosmic time by determining the mechanical luminosity function (LF) of radio sources and by comparing it to a previous determination of the bolometric LF of active galactic nuclei (AGN) from X-ray, optical and infrared observations. The mechanical LF of radio sources is computed in two steps: the determination of the mechanical luminosity as a function of the radio luminosity and its convolution with the radio LF of radio sources. Even with the large uncertainty deriving from the former, we can conclude that the contribution of jets is unlikely to be much larger than ∼10 per cent of the AGN energy budget at any cosmic epoch.     

Synthetic stellar and SSP libraries as templates for Gaia simulations

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.     

Anomalously deep earthquakes in northwestern Italy

It is usually assumed that earthquakes in intraplate regions occur in the upper crust, and northwestern Italy is generally assigned to this kind of normal seismicity. In this work, the depth distribution of the events localized in this area by the Istituto Geofisico Geodetico (IGG) seismic network in the period 1991–1997 is analyzed in detail. In particular, the location capability of the network is discussed, adopting as reference quarry blasts (for the epicentral position) and the locations obtained from a dense temporary network (for the depth estimate). Within the so-obtained error limits, the depth distribution of events show a characteristic pattern: while for most of the area covered by the network the well-located seismicity lies within the first 20 km of depth, in a band following the inner arc of the Western Alps, numerous events have anomalously large focal depths, reaching a maximum of 114 km. These depth determinations cannot be attributed to instabilities of the location procedure: different choices of the propagation models used for the hypocentral determination led to very similar depth values, always significantly larger than the standard values for the surrounding areas. A strong correlation has been found between the 3-dimensional distribution of these foci and the P-wave propagation anomalies obtained from tomographic studies, suggesting a direct link between elastic and rheological properties of lower crust and upper mantle in this area.     

Seismic hazard in the Northwestern Apennines

A study of the seismic hazard for the Northwestern Apennines, based on seismotectonic and seismicity data, is presented. Starting from a seismotectonic analysis, showing the complex structural evolution of the region, the seismic activity in the period 1000–1975 has been modeled by some seismic source zones justified by geostructural and seismological considerations. The recurrence statistical parameters and the attenuation laws have been determined for all these sources. With an appropriate analysis method, maps of seismic hazard for return periods of 50, 200, and 500 years were elaborated. Finally, a comparison with the map of maximum felt intensity and with hazard values calculated by a different approach is presented.     

Mechanisms of galena dissolution in oxygen-saturated solutions: Evaluation of pH effect on apparent activation energies and mineral-water interface

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.     

Source study and tectonic implications of the 1995 Ventimiglia (border of Italy and France) earthquake (ML=4.7)

We analyse the source process and the aftershock distribution of the April 21, 1995, Ventimiglia, M_L=4.7 earthquake using the records of permanent high dynamic broad-band seismic stations and a temporary network deployed on land and at sea few hours after the earthquake. This event occurred on the western Mediterranean coast, near the border between Italy and France, at a depth of 9 km, at a point where Alpine tectonic units and Late Oligocene extensional structure overlap and are currently undergoing compressional stress. The focal solutions of the mainshock and three aftershocks depict a dominant reverse faulting with an important strike-slip component, which underlines two nodal planes: a NW–SE-dipping north fault and a NE–SW-dipping south fault. We operate a careful re-location of the aftershocks using a master-event technique and data from the temporal network and obtain a predominant NW–SE alignment. Then, we analyse the rupture process using an empirical Green function approach. We find that the mainshock broke a 0.5 to 1 km fault length and that the rupture propagated during 0.1–0.2 s probably in a SE direction. Those two arguments, together with the recent fault trace that exists close to the epicentre, leads us to propose that this event expresses the reactivation of an old transverse NW–SE structure with a dextral movement. This study thus emphasizes the role of inherited, deep-rooted, transcurrent features in the tectonic reactivation of this passive margin. It also underlines the importance of combining short-period and broad-band seismology to better resolve and understand regional tectonic processes in areas of moderate seismic activity and complex geology.