The Holocene marine depositional event in the historical centre of Palermo

Studi recenti hanno indicato come al di sopra della classica sequenza del Quaternario marino della Piana di Palermo ricorra, in alcunisiti del Centro Storico, un limitato spessore di depositi marini di età post-tirreniana. Con lo scopo di precisare l’età di tali depositi sonostate studiate le associazioni di microfossili di campioni provenienti da sondaggi geognostici. Utilizzando lo schema ecobiozonale anannofossili calcarei recentemente proposto per l’ultima deglaciazione nel Mediterraneo centrale (Canale di Sicilia) detti depositi contengononannoflore attribuibili all’Olocene. Un'analisi al radiocarbonio ha confermato tale attribuzione, limitando alla parte bassadell'Olocene la pertinenza stratigrafica di tali depositi.Recent data have pointed out that, above the classical depositional sequence of the Quaternary marine sediments of the PalermoCoastal plain, post-Tyrrhenian sediments occur. In order to determine the age of these sediments and to confirm the deposition of arecent sedimentary cycle, microfossil assemblage of several samples, coming from geognostic drillings, have been analysed. Usingthe calcareous nannofossil ecobiozone scheme recently proposed for the last deglaciation of the central Mediterranean (SicilyChannel), examined sediments can be ascribed to the Holocene. Radiocarbon analysis confirmed such an attribution providing a moreaccurate stratigraphic determination

HIGH RESOLUTION CHRONOLOGY FOR LATE MIOCENE MEDITERRANEAN STRATIGRAPHIC EVENTS

&nbsp

Anonymous crypt P2P. A model for a secure and private communication

The aim of this work is to contribute to the modelling of a peer-to-peer protocol in order to fill a lack that still remains in the wide panorama of developed model, i.e. .e. a deterministic anonymous and crypt peer-to-peer communication system. This work considers first the most important model confirmed by the diffusion and the reliability for their purposes, presenting an overview that focuses on the main characteristics. Than an analysis of the requirements is done and two different strategies are analysed, building two models for different anonymity and security levels. The two models are discussed and a communication protocol for a minimal user client interface is described. Finally the scalability problem is discussed

PALEOCEANOGRAPHIC CONDITIONS AT THE BASE OF THE PLIOCENE IN THE SOUTHERN MEDITERRANEAN BASIN

Detailed quantitative analyses of the benthic foraminiferal assemblage from the base of the Pliocene sections (M Pl 1 biozone) at Eraclea Minoa and the Capo Rossello area (southern Sicily) documented fluctuating paleoecological conditions indicative of a dysaerobic bottom water environment. In particular, we identify the Uvigerina pygmaea-peregrina Event, which in the area studied covers the upper part of the M Pl 1 biozone. According to the integrated calcareous plankton biostratigraphy and to cyclostratigraphy based on fluctuations in the relative abundance of fauna in the planktonic foraminiferal assemblage, the base of the Uvigerina pygmaea-peregrina Event coincides with cycle 6a and its top coincides with cycle 10 in the Sicilian sections.A similar temporal correlation is seen in the Tyrrhenian basin (ODP Site 652). On the contrary, the Uvigerina pygmaea-peregrina Event covers a longer time interval in the Jonian basin, where it is recognizable from cycle 4 to cycle 12. The Uvigerina pygmaea-peregrina Event is time equivalent with an interval characterized by cyclically repeated sapropels in the eastern Mediterranean basin. As a matter of fact, 10 sapropels are present in the deep-sea sediments (ODP Site 969) and 10 Uvigerina pygmaea-peregrina peaks are present in the Roccella Ionica - Capo Spartivento composite section in the M Pl 1- lowest M Pl 2 biozones. The diachronous termination of the Uvigerina pygmaea-peregrina Event may indicate that well-oxygenated bottom conditions were established earlier in the western than in the eastern Mediterranean basin. Both the sapropels interval in the eastern Mediterranean and low-oxygen bottom conditions in the Jonian basin occurred during a time interval which straddles a minimum of eccentricity in the astronomical record.  &nbsp

Extended narrow-line region in Seyfert galaxies

We present our recent results about the extended narrow-line region (ENLR) of two nearby Seyfert 2 galaxies (IC 5063 and NGC 7212) obtained by modelling the observed line profiles and spectra with composite models (photoionization+shocks) in the different regions surrounding the AGN. Then, we compare the Seyfert 2 ENLRs with the very extended one recently discovered in the narrow-line Seyfert 1 (NLS1) galaxy Mrk 783. We have found several evidences of interaction between the ISM of the galaxies and their radio jets, such as a) the contribution of shocks in ionizing the high velocity gas, b) the complex kinematics showed by the profile of the emission lines, c) the high fragmentation of matter, etc. The results suggest that the ENLR of IC 5063 have a hollow bi-conical shape, with one edge aligned to the galaxy disk, which may cause some kind of dependence on velocity of the ionization parameter. Regarding the Mrk 783 properties, it is found that the extension of the optical emission is almost twice the size of the radio one and it seems due to the AGN activity, although there is contamination by star formation around 12 arcsec from the nucleus. Diagnostic diagrams excluded the contribution of star formation in IC 5063 and NGC 7212, while the shock contribution was used to explain the spectra emitted by their high velocity gas.Comment: 9 pages, 2 figures, proceeding of the conference "Quasars at all cosmic epochs", accepted for publication in Front. Astron. Space Sci. - Milky Way and Galaxie

Influence of Storage Media on Color Stability of Different Resin Composites as Determined by \u394E and \u394E00

Objective: To evaluate the color stability of 3 different resin composites when exposed to storage in water, air or artificial saliva. Materials and Methods: Initial color of 81 specimens was assessed by a calibrated reflectance spectrophotometer over a black as well as a white background. Specifically, 9 disc shaped specimens made out of 3 resin composite materials were kept in distilled water, air and artificial saliva (Glandosane) at 37\ub0C. After a storage period of 4 weeks, spectrophotometric measurements were repeated and the color changes calculated by means of \u394E and \u394E00. Results: When analysed over a white background, median \u394E values varied from 0.6 (Filtek Supreme Dentin/water) to 7.1 (Filtek Supreme Enamel/Glandosane). When analysed over a black background median \u394E values varied from 0.4 (Filtek Supreme Dentin/water) to 5.0 (Filtek Supreme Enamel/Glandosane). When analysed over a white background, median \u394E00 values varied from 0.4 (Filtek Supreme Dentin/water) to 4.6 (Filtek Supreme Enamel/Glandosane). When analysed over a black background median \u394E00 values varied from 0.4 (Filtek Supreme Dentin/water) to 4.6 (Filtek Supreme Enamel/Glandosane). Statistical analysis performed by means of ANOVA and Fisher\u2019s LSD post hoc tests showed differences between groups. The correlation between \u394E and \u394E00 was 99.09% and 99.65% over black and white background, respectively. Conclusion: Within the limits of the present study, storage media significantly influenced color stability of resin composites

Enhancement of three-mode optomechanical interaction by feedback-controlled light

We realise a feedback-controlled optical Fabry-Perot cavity in which the transmitted cavity output is used to modulate the input amplitude fluctuations. The resulting phase-dependent fluctuations of the in-loop optical field, which may be either sub-shot- or super-shot-noise, can be engineered to favorably affect the optomechanical interaction with a nanomechanical membrane placed within the cavity. Here we show that in the super-shot-noise regime ("anti-squashed light") the in-loop field has a strongly reduced effective cavity linewidth, corresponding to an increased optomechanical cooperativity. In this regime feedback improves the simultaneous resolved sideband cooling of two nearly degenerate membrane mechanical modes by one order of magnitude.Comment: 16 pages, 11 figure

Enhancing sideband cooling by feedback--controlled light

We realise a phase-sensitive closed-loop control scheme to engineer the fluctuations of the pump field which drives an optomechanical system, and show that the corresponding cooling dynamics can be significantly improved. In particular, operating in the counter-intuitive "anti-squashing" regime of positive feedback and increased field fluctuations, sideband cooling of a nanomechanical membrane within an optical cavity can be improved by 7.5~dB with respect to the case without feedback. Close to the quantum regime of reduced thermal noise, such feedback-controlled light would allow going well below the quantum backaction cooling limit