Transforming observational data and theoretical isochrones into the ACS/WFC Vega-mag system     

Luigi R. Bedin †  Santi Cassisi  Fiorella Castelli  Giampaolo Piotto  Jay Anderson  Maurizio Salaris  Yazan Momany  Adriano Pietrinferni 《Monthly notices of the Royal Astronomical Society》2005,357(3):1038-1048

We propose a zero-point photometric calibration of the data from the Advanced Camera for Surveys (ACS) Wide Field Channel (WFC) on board the Hubble Space Telescope , based on a spectrum of Vega and the most up-to-date in-flight transmission curves of the camera. This calibration is accurate at the level of a few hundredths of a magnitude. The main purpose of this effort is to transform the entire set of evolutionary models into a simple observational photometric system for ACS/WFC data, and to make them available to the astronomical community. We provide the zero-points for the most used ACS/WFC bands, and give basic recipes for calibrating both the observed data and the models. We also present the colour–magnitude diagram from ACS data of five Galactic globular clusters, spanning the metallicity range  −2.2 <[Fe/H] < −0.04  , and we provide fiducial points representing their sequences from several magnitudes below the turn-off to the red giant branch tip. The observed sequences are compared with the models in the newly defined photometric system.  相似文献   

Palaeo-carbonate seep structures above an oil reservoir, Gryphon Field, Tertiary, North Sea     

Adriano Mazzini  D. Duranti  R. Jonk  J. Parnell  B. T. Cronin  A. Hurst  M. Quine 《Geo-Marine Letters》2003,23(3-4):323-339

Petrographic and geochemical analyses performed on a North Sea core from the Gryphon Field reveal the presence of palaeo-degassing features surrounded by injected sandstones in the Eocene interval. The injected sandstones are oil-stained and poorly cemented by carbonate and quartz. ¹⁸O isotope analyses indicate that carbonate cementation occurred during shallow burial (likely less than about 300 m). Depleted ¹³C (around –30 V-PDB) carbonate cement suggests that bicarbonate was derived from the microbial oxidation of oil and gas. Late quartz overgrowths enclose oil present in the injected units. The tubular degassing conduits are composed of zoned cements and have ¹⁸O and ¹³C isotope values similar to the injected sandstones, indicating that oil and gas seepage induced the precipitation of authigenic carbonate in the shallow subsurface. Oil inclusions in inter- and intra-crystal cement sites in both injected sandstones and degassing conduits indicate that oil seepage was an ongoing feature at shallow burial. A proposed model involves oil and gas seepage and the formation of the degassing conduits, followed by a sand injection phase. It seems likely that oil and gas continued to leak towards the seabed by exploiting the network of permeable injected sandstones and the horizons of porous degassing features.  相似文献   

Vertical distribution of the macrobenthic community and its relationships to trace metals and natural sediment characteristics in the lower Douro estuary, Portugal   总被引：2，自引：0，他引：2  

Ana P. Mucha  M. Teresa S. D. Vasconcelos  Adriano A. Bordalo   《Estuarine, Coastal and Shelf Science》2004,59(4):663

Vertical distribution (0–15 cm) of the macrobenthic community and its relationships to natural sediment characteristics and trace metal contents and bioavailability were studied at five locations in the lower Douro estuary, Portugal. An analysis of vertical metal distribution, for the interpretation of anthropogenic impact on the estuarine sediments, was also investigated. Sediment characterisation included organic matter, grain size, metals (Al, Fe, Cu, Pb, Cr, Ni, Cd, Zn and Mn), acid volatile sulphide (AVS) and simultaneously extracted metals (SEM). The macrobenthic community had low diversity (14 species), was dominated by small size opportunists and seemed to be controlled mainly by natural factors such as grain size distribution, Al and Fe contents and sediment depth. The vertically heterogeneous distribution of macrobenthic community appears to affect redox status of the sediments and consequently metal bioavailability. Despite anthropogenic contamination in terms of Zn, Cu, Pb, Cr and Ni having already been detected in the north bank, the analysis of vertical distribution was essential for the identification of current anthropogenic contamination in terms of Zn, Pb and Cd in the south bank.  相似文献   

Using radon-222 to study coastal groundwater/surface-water interaction in the Crau coastal aquifer (southeastern France)     

Adriano Mayer  Bach Thao Nguyen  Olivier Banton 《Hydrogeology Journal》2016,24(7):1775-1789

Radon has been used to determine groundwater velocity and groundwater discharge into wetlands at the southern downstream boundary of the Crau aquifer, southeastern France. This aquifer constitutes an important high-quality freshwater resource exploited for agriculture, industry and human consumption. An increase in salinity occurs close to the sea, highlighting the need to investigate the water balance and groundwater behavior. Darcy velocity was estimated using radon activities in well waters according to the Hamada “single-well method” (involving comparison with radon in groundwater in the aquifer itself). Measurements done at three depths (7, 15 and 21 m) provided velocity ranging from a few mm/day to more than 20 cm/day, with highest velocities observed at the 15-m depth. Resulting hydraulic conductivities agree with the known geology. Waters showing high radon activity and high salinity were found near the presumed shoreline at 3,000 years BP, highlighting the presence of ancient saltwater. Radon activity has also been measured in canals, rivers and ponds, to trace groundwater discharges and evaluate water balance. A model of the radon spatial evolution explains the observed radon activities. Groundwater discharge to surface water is low in pond waters (4 % of total inputs) but significant in canals (55 l/m²/day).  相似文献   

Preface to special issue VII workshop on catastrophic disruption in the Solar System     

Adriano Campo Bagatin 《Planetary and Space Science》2009,57(2):109-110

  相似文献   

Evolutionary and structural properties of mirror star MACHOs     

Zurab Berezhiani  Paolo Ciarcelluti  Santi Cassisi  Adriano Pietrinferni   《Astroparticle Physics》2006,24(6):495-510

There can exist a hidden sector of the Universe in the form of parallel “mirror” world which has the same particle physics as the observable world and interacts with the latter only gravitationally. Big Bang nucleosynthesis bounds demand that the mirror sector should have a smaller temperature than the ordinary one. This implies that the mirror matter could play a role of dark matter, and in addition its chemical content should be dominated by helium. Here we study the evolutionary and structural properties of the mirror stars which essentially are similar to that of the ordinary stars but with higher helium contents. Being invisible in terms of photons, they could be observed only as MACHOs in the microlensing experiments. Using a numerical code, we compute evolution of stars with large helium abundances (Y = 0.30–0.80) and a wide range of masses, from 0.5 to 10 M. We found that helium dominated mirror star should have much faster evolutionary time (up to a factor 30) than the ordinary star with the same mass. In addition, we show the diagrams of luminosities, effective temperatures, central temperatures and densities, and compute the masses of the He-core at ignition and the minimum mass for carbon ignition, for different chemical compositions. The general conclusion is that mirror stars evolve faster as compared to ordinary ones, and explode earlier as type II supernovae, thus enriching the galactic halo of processed mirror gas with higher metallicity, with implications for MACHO observations and galaxy evolution.  相似文献   

Retracking considerations in spaceborne GNSS-R altimetry   总被引：1，自引：0，他引：1  

Hyuk Park  Adriano Camps  Enric Valencia  Nereida Rodriguez-Alvarez  Xavier Bosch-Lluis  Isaac Ramos-Perez  Hugo Carreno-Luengo 《GPS Solutions》2012,16(4):507-518

The European Space Agency Passive Reflectometry and Interferometry System In-orbit Demonstrator (IoD) aims to perform mesoscale altimetric observations by measuring the Global Navigation Satellite System (GNSS) opportunity signals reflected over the sea surface. Altimetry based on GNSS reflectometry (GNSS-R) is significantly affected by satellite motion, since it requires relatively long integration times to reduce noise. We present the impact of the satellite motion on the GNSS-R observables and the need to retrack the waveforms. By using a detailed GNSS-R space mission simulator, the change of delay difference between the direct and the reflected signals during the incoherent averaging of the waveform has been investigated. Their effects on the waveform shape and the altimetric performance are presented comparing the aligned and non-aligned waveforms. Results show that the performance of spaceborne GNSS-R altimeter is seriously degraded without a proper alignment of the waveform samples.  相似文献   

A 180 ka record of environmental change at Erdut (Croatia): a new chronology for the loess–palaeosol sequence and its implications for environmental interpretation     

Kaja Fenn  Julie A. Durcan  David S. G. Thomas  Adriano Banak 《第四纪科学杂志》2020,35(4):582-593

While there are numerous thick loess–palaeosol sequences preserved across the Carpathian Basin, well dated sites that provide terrestrial palaeoenvironmental records extending beyond last glacial–interglacial cycle are scarce. Robust chronologies are essential for correlations of loess with other long-term Quaternary records and to further understanding of the palaeoenvironment and climate of this important region beyond the last 125 ka. Here a new geochronology based on 13 post-infrared infrared stimulated luminescence ages focused on the lower part of the loess–palaeosol sequence at Erdut is presented. The results show that the lower part of the Erdut profile spans the penultimate glacial cycle (MIS 7 to MIS 5). The considerable sediments overlaying the investigated part of the profile suggest that this section spans two glacial cycles, rather than the previously suggested one. The most likely source of the discrepancy is the use of uncorrected infrared stimulated luminescence signal, which can cause age underestimation if not accounted for. This study demonstrates the need to revisit sites such as Erdut, re-date them using updated measurement protocols, and update existing palaeoenvironmental interpretations.  相似文献   

Recent Advances in Agent-Based Tsunami Evacuation Simulations: Case Studies in Indonesia,Thailand, Japan and Peru   总被引：1，自引：0，他引：1  

Erick Mas  Shunichi Koshimura  Fumihiko Imamura  Anawat Suppasri  Abdul Muhari  Bruno Adriano 《Pure and Applied Geophysics》2015,172(12):3409-3424

  相似文献   

Comparative analysis of phytoplankton patterns in two modified lakes with contrasting hydrological features   总被引：1，自引：0，他引：1  

Monica Tolotti  Adriano Boscaini  Nico Salmaso 《Aquatic Sciences - Research Across Boundaries》2010,72(2):213-226

Hydrological management represents one of the main factors controlling physical and chemical characteristics as well as biodiversity and productivity of planktonic communities in artificial and modified lakes. In Alpine piedmont reservoirs, which often receive large water inputs from high altitude watersheds, control operated by hydrological regime over ecological processes is also mediated by other related variables such as water temperature and turbulence, and load of inorganic suspended solids. This contribution reports on results obtained from a comparative study on the impact of hydrological regime on phytoplankton patterns in two modified piedmont lakes of different size and hydrology located in the NE Italian Alps: Lake Santa Croce (V = 147 × 10⁶ km³) and Lake Toblino (V = 5.7 × 10⁶ km³). Phytoplankton of both lakes was characterised by a pronounced dominance of diatoms, accompanied by cryptophytes and green algae. The mesotrophic Lake Santa Croce showed a typical seasonal succession of dominant groups, while phytoplankton growth in the eutrophic Lake Toblino was variable and showed pronounced pulses in relation to dramatic changes in the hydrological regime. The comparative study of phytoplankton, based on morpho-functional classification and application of multivariate analyses (non-metric multidimensional scaling, principal components analysis, and redundancy analysis), showed that hydrological regime affected phytoplankton growth in the two lakes both directly, i.e. through renewal time, and indirectly, i.e. regulating thermal conditions in Lake Santa Croce and nutrient availability in both lakes. Nevertheless, effectiveness of hydrological constraints largely depended on lake size and morphology, being more pronounced in the shallower and smaller Lake Toblino.  相似文献