The Cengio submarine turbidite system of the Tertiary Piedmont Basin, Northwestern Italy     

Carlo Cazzola  Emiliano Mutti  Bartolomeo Vigna 《Geo-Marine Letters》1984,3(2-4):173-177

The Cengio sandstone member of the Tertiary Piedmont Basin in northwestern Italy has a conservatively estimated volume of 2.5 to 3 km³ (length: 6.4 km; width: 4.8 km; thickness: 170 m). It is interpreted as a sandstone-rich submarine fan deposit. The Cengio member consists of eight tabular depositional sandstone lobes that are 5- to 25-m thick. These lobes filled a submarine structural depression and onlap and/or pinch-out against bounding slope mudstones. The stacking of the lobe units was related to synsedimentary tectonism. Margin setting represents fan and/or source area  相似文献   

The organisational context of retail locational planning   总被引：1，自引：0，他引：1  

Tony Hernandez  David Bennison  Sarah Cornelius 《GeoJournal》1998,45(4):299-308

Retailers have a large number of techniques at their disposal to assist them in their locational planning, but the use made of them is varied, regardless of their intrinsic merits. The reasons for this lie very much in the organisational context in which the techniques are applied. This paper discusses the nature of locational planning and decision making, and puts forward a framework which links locational planning and the organisational settings in which it takes place. The preliminary results of a survey of the use of techniques by U.K. retailers are presented, which show that while most companies use more than ‘Rules of Thumb’, it is the simplest techniques which are the most widely used. The application of the more advanced knowledge based methods is still relatively uncommon. The explanation for the variations lies in the attributes of the techniques themselves, the types of locational planning undertaken, and the structural and cultural characteristics of the companies. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Dynamical friction in dwarf galaxies     

X. Hernandez  & Gerard Gilmore 《Monthly notices of the Royal Astronomical Society》1998,297(2):517-525

We present a simplified analytic approach to the problem of the spiralling of a massive body orbiting within the dark halo of a dwarf galaxy. This dark halo is treated as the core region of a King distribution of dark matter particles, in consistency with the observational result of dwarf galaxies having solid-body rotation curves. Thus we derive a simple formula which provides a reliable and general first-order solution to the problem, totally analogous to the one corresponding to the dynamical friction problem in an isothermal halo. This analytic approach allows a clear handling and a transparent understanding of the physics and the scaling of the problem. A comparison with the isothermal case shows that in the core regions of a King sphere, dynamical friction proceeds at a different rate, and is sensitive to the total core radius. Thus, in principle, observable consequences may result. In order to illustrate the possible effects, we apply this formula to the spiralling of globular cluster orbits in dwarf galaxies, and show how present-day globular cluster systems could, in principle, be used to derive better limits on the structure of dark haloes around dwarf galaxies, when the observational situation improves. As a second application, we study the way a massive black hole population forming a fraction of these dark haloes would gradually concentrate towards the centre, with a consequent deformation of an originally solid-body rotation curve. This effect allows us to set limits on the fraction/mass of any massive black hole minority component of the dark haloes of dwarf galaxies. In essence, we take advantage of the way the global matter distribution fixes the local distribution function for the dark matter particles, which in turn determines the dynamical friction problem.  相似文献   

Hepatic histopathology in two populations of the mummichog, Fundulus heteroclitus     

W. F. Schmalz  Jr.  A. D. Hernandez  P. Weis   《Marine environmental research》2002,54(3-5)

The pollution-tolerant mummichog, Fundulus heteroclitus, inhabits a heavily contaminated estuary, Piles Creek (PC), in Linden, NJ. PC contaminants include PAHs, PCBs and many metals, including high Hg and Pb. PC mummichog livers and kidneys were compared with those from a pristine estuary in Tuckerton (TK), NJ, by standard histopathological methods, with quantification by computerized image analysis. PC livers had>2× the lipid ratios of TK livers. Cell sizes and shapes were not different between populations. TK livers had a 25% incidence of basophilic areas and an age-related 30% incidence of macrophage aggregates; PC livers had none of these lesions. PC livers had a 100% incidence of necrotic foci, compared with 55% of TK livers. Inflammation was noted in 50% of TK livers but only 27% of PC livers. Curiously, the TK livers had a 45% incidence of metacercarial cysts of a digenetic trematode, while none were found in the PC livers. The TK focal necrosis and macrophage aggregates coincided with parasite infestation. There were no observed kidney lesions in either population. Positive biomarkers in this species thus included high hepatic lipid content, possibly necrosis, but no other lesions. The lack of trematode cysts in PC livers may reflect the lack of an intermediate host in this low biodiversity estuary.  相似文献   

Ontology‐supported Querying of Geographical Databases     

Miriam Baglioni  Emiliano Giovannetti  Maria Vittoria Masserotti  Chiara Renso  Laura Spinsanti 《Transactions in GIS》2008,12(Z1):31-44

Querying geographical information systems has been recognized as a difficult task for non‐expert users. Furthermore, user queries are often characterized by semantic aspects not directly managed by traditional spatial databases or GIS. Examples of such semantic geospatial queries are the use of implicit spatial relations between objects, or the reference of domain concepts not explicitly represented in data. To handle such queries, we envisage a system that translates natural language queries into spatial SQL statements on a database, thus improving standard GIS with new semantic capabilities. Within this general objective, the contribution of this article is to introduce a methodology to handle semantic geospatial queries issued over a spatial database. This approach captures semantics from an ontology built upon the spatial database and enriched by domain concepts and properties specifically defined to represent the localization of objects. Some examples of the use of the methodology in the urban domain are presented.  相似文献   

Helium isotopes in the Izu Peninsula,Japan: Relation of magma and crustal activity     

Masao Ohno  Hirochika Sumino  Pedro A. Hernandez  Tsutomu Sato  Keisuke Nagao 《Journal of Volcanology and Geothermal Research》2011,199(1-2):118-126

The relation of magma and crustal activity has been studied from spatial distribution of ³He/⁴He ratios of gas and/or water samples over the Izu Peninsula, where significant crustal deformation associated with seismic swarm activities has been observed since 1970s. The air-corrected values of ³He/⁴He ratios ranged from 3.5 to 8.2 R_A, where R_A is the atmospheric ³He/⁴He ratio = 1.4 × 10^? 6, indicating that helium is mostly of magmatic origin. Among the three pressure sources proposed to explain the crustal deformation, two inflation sources beneath the inland of northeast and the mid east coast of the Izu Peninsula locate in the broad distribution of high ³He/⁴He ratios, which supports relation of magma to the crustal uplift. In contrast, the distribution of ³He/⁴He ratios around the tensile fault assumed in the area of seismic swarms appears not to indicate existence of significant amount of magma below the tensile fault. Alternatively, the results suggest magma below a point several kilometers south of the tensile fault. The seismic swarms are explained either by fluid pressurization of thermal water heated by this magma or by intrusion of magma to the tensile fault moved obliquely from the deep magma reservoir.  相似文献   

Carbon dioxide and helium dissolved gases in groundwater at central Tenerife Island,Canary Islands: chemical and isotopic characterization     

Rayco Marrero-Diaz  Dina López  Nemesio M. Perez  Emilio Custodio  Hirochika Sumino  Gladys V. Melián  Eleazar Padrón  Pedro A. Hernandez  David Calvo  José Barrancos  Germán Padilla  Francesco Sortino 《Bulletin of Volcanology》2015,77(10):1-18

  相似文献   

Semi-analytical solutions for stream–aquifer interactions under triangular stream-stage variations and its application to study urbanization impacts in an ungaged watershed of south Texas     

E. Annette Hernandez  Venkatesh Uddameri 《Environmental Earth Sciences》2014,71(6):2547-2557

Simple yet physically based models to evaluate stream–aquifer interactions during a flooding event subject to triangular stream stage variation were developed in this study. The results from the developed models were compared with other analytical and numerical solutions and noted to be very accurate. The study fills an important gap with regard to available analytical and semi-analytical solutions for modeling stream–aquifer interactions, which can be used for evaluating numerical codes. In particular, the developed models are very useful to obtain preliminary insights with regard to bank storage in ungaged watersheds as required for watershed management and planning studies in rapidly urbanizing watersheds. The utility of the model is illustrated by applying it to study the effects of urbanization on stream–aquifer interactions in the Arroyo Colorado River Watershed along the US–Mexico border region. The results indicate that increased urbanization reduces the amount of influx into the banks. The reduction in flood passage time was noted to have a greater impact than the associated rise in stage. The presence of a semi-permeable barrier was seen to mask the effects of urbanization. The model results also implicitly highlight the importance of how water quality variations caused due to urbanization can affect stream–aquifer interactions.  相似文献   

Assessment of groundwater water quality in central and southern Gulf Coast aquifer,TX using principal component analysis     

Venkatesh Uddameri  Vivekanand Honnungar  E. Annette Hernandez 《Environmental Earth Sciences》2014,71(6):2653-2671

Principal component analysis has been applied for source identification and to assess factors affecting concentration variations. In particular, this study utilizes principal component analysis (PCA) to understand groundwater geochemical characteristics in the central and southern portions of the Gulf Coast aquifer in Texas. PCA, along with exploratory data analysis and correlation analysis is applied to a spatially extensive multivariate dataset in an exploratory mode to conceptualize the geochemical evolution of groundwater. A general trend was observed in all formations of the target aquifers with over 75 % of the observed variance explained by the first four factors identified by the PCA. The first factor consisted of older water subjected to weathering reactions and was named the ionic strength index. The second factor, named the alkalinity index explained greater variance in the younger formations rather than in the older formations. The third group represented younger waters entering the aquifers from the land surface and was labeled the recharge index. The fourth group which varied between aquifers was either the hardness index or the acidity index depending on whether it represented the influences of carbonate minerals or parameters affecting the dissolution of fluoride minerals, respectively. The PCA approach was also extended to the well scale to determine and identify the geographic influences on geochemical evolution. It was found that wells located in outcrop areas and near rivers and streams had a larger influence on the factors suggesting the importance of surface water–groundwater interactions.  相似文献   

Identifying influencing wells for gradient estimation in the confined portion of the Gulf Coast aquifer near Kingsville,TX     

Venkatesh Uddameri  Sreeram Singaraju  E. Annette Hernandez 《Environmental Earth Sciences》2014,71(6):2629-2640

Hydraulic gradient is a fundamental aquifer characteristic required to estimate groundwater flow and quantify advective fluxes of pollutants. Graphical and local estimation schemes using potentiometric head information from three or four wells are used to compute hydraulic gradients but suffer from imprecision and subjectivity. The use of linear regression is recommended when hydraulic head data from a groundwater monitoring network consisting of several wells are available. In such cases, statistical influence analysis can be carried out to evaluate how each well within the network impacts the gradient estimate. A suite of five metrics, namely—(1) the hat-values, (2) studentized residuals, (3) Cook’s distance, (4) DFBETAs and (5) Covariance ratio (COVRATIO) are used in this study to identify influential wells within a regional groundwater monitoring network in Kleberg County, TX. The hat-values indicated that the groundwater network was reasonably well balanced and no well exerted an undue influence on the regression. The studentized residuals and Cook’s distance indicated the wells with the highest influence on the regression predictions were those that were close to high groundwater production centers or affected by coastal-aquifer interactions. However, the wells in the proximity of the production centers had the highest impact on the estimated gradient values as ascertained using DFBETAs. The covariance ratio which indicates the sensitivity of a monitoring well on the estimated standard error of regression was noted to be significant at most wells within the network. Therefore, networks seeking to address changes in groundwater gradients due to climate and anthropogenic influences need to be denser than those used to ascertain synoptic gradient estimates alone. The magnitude of the groundwater velocity was greatly underestimated when the influential wells were excluded from the network. The direction of flow was affected to a lesser extent, but a complete gradient reversal was noted when the network consisted of only four peripheral wells. The influence analysis therefore provides a valuable tool to assess the importance of individual wells within a monitoring network and can therefore be useful when existing networks are to be pruned due to fiscal constraints.  相似文献