Assessment and mapping of the intrinsic vulnerability to pollution: an example from Keritis River Basin (Northwestern crete, Greece)   总被引：1，自引：1，他引：0  

S. Parisi  S. Pascale  F. Sdao  P. Soupios 《Environmental Earth Sciences》2013,70(6):2659-2670

Due to the geological and hydrogeological characteristics, the carbonate aquifers are frequently vulnerable to natural and/or anthropogenic polluting sources. The aim of the present study is to evaluate the intrinsic vulnerability to pollution of the Keritis River Basin (northwestern Crete, Greece). The huge amount of the flowing groundwater represents a strategic water resource to be allocated to drinking water purpose and to agricultural activities, too. The studied groundwater are characterized by quality degradation processes represented by the anthropogenic and natural pollution such as olive oil farming, agriculture activities, industrial waste and salt water intrusion. For a better management and protection of the water resources, the assessment and mapping of groundwater vulnerability to pollution are very important. From this investigation, the Keritis Basin showed an intrinsic vulnerability degree from extremely high to very low. This study allows to define the strategies which will permit a proper safeguard criteria, against the pollution sources of the Keritis Basin groundwater resources.  相似文献   

Star formation histories of local group dwarf galaxies     

Chisato Ikuta  Nobuo Arimoto  Pascale Jablonka 《Astrophysics and Space Science》2003,284(2):589-594

We present the study of the star formation histories (SFHs) of a sample of Local Group dwarf galaxies (LGDGs), via the analysis and modelling, with the means of an evolutionary stellar population synthesis, of their colour-magnitude (CM) diagrams. It appears that important parameters to describe the SFHs are star formation rate (SFR) and duration of star formation. We find a possible correlation between the mass and the SFRs. The correlation might be the origin of the observed luminosity-metallicity relation in the LGDGs. A well-defined correlation between the durations of star formation and the distance from M31 or the Galaxy indicates that the current early-type dwarf galaxies should have been transformed from late-type by strong tidal force of the massive galaxies. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Chemical and dynamical evolution of spiral galaxies     

Sébastien Poirier  Pascale Jablonka  Jean-Michel Alimi 《Astrophysics and Space Science》2003,284(2):849-852

We investigate the consequences of the hypothesis of the secular evolution (growth of the bulge from disc material via a bar and temporal evolution of the Hubble sequence) on the chemical evolution of a galaxy. We present the first dynamical and chemical results of our 3D tree-SPH simulations. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

A laboratory model of splash‐form tektites     

Linda T. ELKINS‐TANTON  Pascale AUSSILLOUS  Jos BICO  David QUR  John W. M. BUSH 《Meteoritics & planetary science》2003,38(9):1331-1340

Abstract— Splash‐form tektites are generally acknowledged to have the form of bodies of revolution. However, no detailed fluid dynamical investigation of their form and stability has yet been undertaken. Here, we review the dynamics and stability of spinning, translating fluid drops with a view to making inferences concerning the dynamic history of tektites. We conclude that, unless the differential speed between the molten tektite and ambient is substantially less than the terminal velocity, molten tektites can exist as equilibrium bodies of revolution only up to sizes of 3 mm. Larger tektites are necessarily non‐equilibrium forms and so indicate the importance of cooling and solidification during flight. An examination of the shapes of rotating, translating drops indicates that rotating silicate drops in air will assume the shapes of bodies of rotation if their rotational speed is 1% or more of their translational speed. This requirement of only a very small rotational component explains why most splash‐form tektites correspond to bodies of revolution. A laboratory model that consists of rolling or tumbling molten metallic drops reproduces all of the known forms of splashform tektites, including spheres, oblate ellipsoids, dumbbells, teardrops, and tori. The laboratory also highlights important differences between rolling drops and tumbling drops in flight. For example, toroidal drops are much more stable in the former than in the latter situation.  相似文献   

A search for interstellar pyrimidine   总被引：1，自引：0，他引：1  

Yi-Jehng Kuan  Chi-Hung Yan  Steven B. Charnley  Zbigniew Kisiel  Pascale Ehrenfreund  Hui-Chun Huang 《Monthly notices of the Royal Astronomical Society》2003,345(2):650-656

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Neural networks and landslide susceptibility: a case study of the urban area of Potenza   总被引：4，自引：1，他引：3  

Donatella Caniani  Stefania Pascale  Francesco Sdao  Aurelia Sole 《Natural Hazards》2008,45(1):55-72

For those working in the field of landslide prevention, the estimation of hazard levels and the consequent production of thematic maps are principal objectives. They are achieved through careful analytical studies of the characteristics of landslide prone areas, thus, providing useful information regarding possible future phenomena. Such maps represent a fundamental step in the drawing up of adequate measures of landslide hazard mitigation. However, for a complete estimation of landslide hazard, meant as the degree of probability that a landslide occurs in a given area, within a given space of time, detailed and uniformly distributed data regarding their incidence and causes are required. This information, while obtainable through laborious historical research, is usually partial, incomplete and uneven, and hence, unsatisfactory for zoning on a regional scale. In order to carry this out effectively, the utilization of spatial estimation of the relative levels of landslide hazard in the various areas was considered opportune. These areas were classified according to their levels of proneness to landslide activity without taking recurrence periods into account. Various techniques were developed in order to obtain upheaval numerical estimates. The method used in this study, which was applied in the area of Potenza, is based on techniques derived from artificial intelligence (Artificial Neural Network—ANN). This method requires the definition of appropriate thematic layers, which parameterize the area under study. These are recognized by means of specific analyses in a functional relationship to the event itself. The parameters adopted are: slope gradient, slope aspect, topographical index, topographical shape, elevation, land use and lithology.  相似文献   

Gravitational deformation and inherited structural control on slope morphology in the subduction zone of north‐central Chile (ca. 29–33°S)          下载免费PDF全文

Juan Becerra  César Arriagada  Eduardo Contreras‐Reyes  Sebastián Bascuñan  Gregory P. De Pascale  Christian Reichert  Juan Díaz‐Naveas  Natalia Cornejo 《Basin Research》2017,29(6):798-815

Subduction zones provide direct insight into plate boundary deformation and by studying these areas we better understand tectonic processes and variability over time. We studied the structure of the offshore subduction zone system of the Pampean flat‐slab segment (ca. 29–33°S) of the Chilean margin using seismic and bathymetric constraints. Here, we related and analysed the structural styles of the offshore and onshore western fore‐arc. Overlying the acoustic top of the continental basement, two syn‐extensional seismic sequences were recognised and correlated with onshore geological units and the Valparaíso Forearc Basin seismic sequences: (SII) Pliocene‐Pleistocene and (SI) Miocene‐Pliocene (Late Cretaceous (?) to Miocene‐Pliocene) syn‐extensional sequences. These sequences are separated by an unconformity (i.e. Valparaíso Unconformity). Seismic reflection data reveal that the eastward dipping extensional system (EI) recognised at the upper slope can be extended to the middle slope and controlled the accumulation of the older seismic package (SI). The westward dipping extensional system (EII) is essentially restricted to the middle slope. Here, EII cuts the eastward dipping extensional system (EI), preferentially parallel to the inclination of the older sequences (SI), and controlled a series of middle slope basins which are filled by the Pliocene‐Pleistocene seismic sequence (SII). At the upper slope and in the western Coastal Cordillera, the SII sequence is controlled by eastward dipping faults (EII) which are the local reactivation of older extensional faults (EI). The tectonic boundary between the middle (eastern outermost forearc block) and upper continental slope (western coastal block) is a prominent system of trenchward dipping normal fault scarps (ca. 1 km offset) that resemble a major trenchward dipping extensional fault system. This prominent structural feature can be readily detected along the Chilean erosive margin as well as the two extensional sets (EI and EII). Evidence of slumping, thrusting, reactivated faults and mass transport deposits, were recognised in the slope domain and locally restricted to some eastern dipping faults. These features could be related to gravitational effects or slope deformation due to coseismic deformation. The regional inclination of the pre‐Pliocene sequences favoured the gravitational collapse of the outermost forearc block. We propose that the structural configuration of the study area is dominantly controlled by tectonic erosion as well as the uplift of the Coastal Cordillera, which is partially controlled by pre‐Pliocene architecture.  相似文献   

Investigating the pace of temperature change and its implications over the twenty-first century     

Yann Chavaillaz  Sylvie Joussaume  Amaury Dehecq  Pascale Braconnot  Robert Vautard 《Climatic change》2016,137(1-2):187-200

Most climatological studies characterize the future climate change as the evolution between a fixed current baseline and the future. However, as climate continues to change, ecosystems and societies will need to continuously adapt to a moving target. Here, we consider indicators of the pace of temperature change estimated from CMIP5 projections of an ensemble of climate models. We define the pace as a difference in relevant metrics between two successive 20-year periods, i.e. with a continually moving baseline. Under the strongest emission pathway (RCP8.5), the warming rate strongly increases, and peaks before 2080. All latitudes experience at least a doubling in the warming rate compared to the current period. Significant shifts in temperature distributions above twice the standard deviation between two successive 20-year periods expand from 9 % of continents on average currently to 41 % by 2060 onwards. In these regions, a warm year with a return period of about 50 years would become quite common 20 years later. The fraction of the world population exposed to such shifts will grow from 8 % to about 60 % on average, i.e. 6 billion people. Tropical areas are strongly affected, especially West Africa and South-East Asia. Low mitigation (RCP6.0) limits the warming rate to current values. Medium mitigation (RCP4.5) even reduces population exposure to significant shifts in temperature distributions to negligible values by the end of the century. Strong mitigation (RCP2.6) is the only option that generates a return to values similar to the historical period for all our indicators related to the pace of temperature change. This alternative way to analyze climate projections can yield new insights for the climate impacts and adaptation communities.  相似文献   

Influences of Natural and Anthropogenic Factors and Tidal Restoration on Terrestrial Arthropod Assemblages in West Coast North American Estuarine Wetlands     

Aaron T. David  Pascale A. L. Goertler  Stuart H. Munsch  Brittany R. Jones  Charles A. Simenstad  Jason D. Toft  Jeffery R. Cordell  Emily R. Howe  Ayesha Gray  Michael P. Hannam  William Matsubu  Erin E. Morgan 《Estuaries and Coasts》2016,39(5):1491-1504

Compared to benthic and water-column invertebrate assemblages, considerably less is known about terrestrial arthropods inhabiting estuarine wetlands despite their importance to tidal wetland biodiversity and productivity. We also need to know more about how human modification of estuaries, including efforts to restore estuarine wetlands, affects these assemblages. To address this knowledge gap, we assembled data from multiple studies on terrestrial arthropod assemblages from 87 intertidal wetland sites in 13 estuaries along the west coast of North America. Arthropods were sampled between 1998 and 2013 with fallout traps deployed in wetlands for 1 to 3 days at a time. We describe patterns in the abundance and taxonomic composition of terrestrial arthropods and evaluate the relative ability of natural and anthropogenic factors to explain variation in abundance and composition. Arthropod abundance was highly variable. Vegetation assemblage, precipitation, and temperature best explained variation in arthropod abundance, while river discharge, latitude, and developed and agricultural land cover surrounding sampling sites were less important. Arthropod abundance rapidly achieved levels of reference wetlands after the restoration of tidal influence to leveed wetlands, regardless of surrounding land cover. However, arthropod assemblage composition was affected by the amount of developed land cover as well as restoration age. These results suggest that restoration of tidal influence to leveed wetlands can rapidly restore some components of estuarine wetland ecosystems but that recovery of other components will take longer and may depend on the extent of anthropogenic modification in the surrounding landscape.  相似文献   

The use of passive treatment alternatives for the mitigation of acidic drainage at the Williams Brother mine,California: Bench-scale study     

Erin J. Clyde  Pascale Champagne  Heather E. Jamieson 《Applied Geochemistry》2010

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