Implementing the Gaia Astrometric Global Iterative Solution (AGIS) in Java     

William O’Mullane  Uwe Lammers  Lennart Lindegren  Jose Hernandez  David Hobbs 《Experimental Astronomy》2011,31(2-3):215-241

  相似文献   

Distribution and chronology of Pleistocene permafrost features in France: Database and first results     

Pascal Bertran  Eric Andrieux  Pierre Antoine  Sylvie Coutard  Laurent Deschodt  Philippe Gardère  Marion Hernandez  Claude Legentil  Arnaud Lenoble  Morgane Liard  Norbert Mercier  Olivier Moine  Luca Sitzia  Brigitte Van Vliet‐Lanoë 《Boreas: An International Journal of Quaternary Research》2014,43(3):699-711

Numerous periglacial features (polygons, nets, soil stripes, ice‐wedge pseudomorphs and sand‐wedge casts, involutions) have been recorded in France by examining bibliographical sources and aerial photographs. These data show that a large part of France was affected by permafrost during the Pleistocene and only the southern Aquitaine Basin and Languedoc seem to have been beyond its maximum extent. The first OSL ages obtained from the aeolian infill of wedge structures indicate that at least two phases of thermal contraction cracking occurred in southwestern France between ～25 and 36 ka. Chronostratigraphical data from loess in northern France indicate that these episodes correspond to the formation of ice‐wedge networks associated with tundra gleys. In the latter region, two additional permafrost episodes probably occurred during the Last Glacial, the older one corresponding to the end of Marine Isotope Stage (MIS) 4 around 60 ka and the more recent one to MIS 2 around 19–16 ka. Although stratigraphical data indicate that these episodes were relatively short (about one millennium), relict permafrost may have existed for longer periods in northern France.  相似文献   

Exploring the Boundaries of Web Map Services: The Example of the Online Injury Atlas for Ontario     

Claus Rinner  Byron Moldofsky  Michael D. Cusimano  Sean Marshall  Tony Hernandez 《Transactions in GIS》2011,15(2):129-145

Injury from causes such as falls, traffic accidents, or violence is a major public health issue globally. Injury prevention research aims to identify vulnerable populations and places by analyzing the spatial patterns of demographic and socio‐economic risk factors associated with elevated injury rates. The stakeholders in injury prevention and control are often distributed across government and public health institutions, non‐profits, and even the private sector (e.g. insurance firms). While this situation calls for distributed, online research tools, their implementation may conflict with health data confidentiality and license limitations for socio‐economic data. In this article, we present the Online Injury Atlas for Ontario, which was designed with the explicit goal of making use of, and contributing to, the Canadian Geospatial Data Infrastructure. We propose a service‐based architecture that integrates publicly accessible map services with protected data layers. Thereby, we demonstrate the benefits of using spatial data infrastructures alongside private data at different levels of protection. In addition, we discuss the extensive data processing needs and specific cartographic design requirements of a Web atlas in the health and social sciences domain.  相似文献   

Basic concepts of the crystallization from aqueous solutions: The example of aluminum oxy(hydroxi)des and aluminosilicates     

Jean-Pierre Jolivet  Corinne Chanéac  David Chiche  Sophie Cassaignon  Olivier Durupthy  Julien Hernandez 《Comptes Rendus Geoscience》2011,343(2-3):113-122

This overview features the chemical background on condensation phenomena of the aluminum cation in aqueous solution. The formation of polycationic molecular clusters and nanosized solid phases of aluminum oxy(hydroxi)des is interpreted with illustrative mechanisms, building a bridge between solution chemistry and solid-state chemistry. The formation of the main structural types of aluminosilicates (zeolites, clays, imogolite) is also illustrated through the aqueous chemistry of aluminum and silicates.  相似文献   

Application of geomorphologic knowledge for erosion hazard mapping     

José Alexander Chávez Hernandez  Jiři Šebesta  Lubomir Kopecky  Reynaldo López Landaverde 《Natural Hazards》2014,71(3):1323-1354

An erosion hazard map was elaborated using geomorphologic and lithological information; this was the base to characterize the erodibility of the territory. The aim of the proposed methodology is to define the areas where more detailed studies are necessary (e.g., to estimate rates of soil erosion, mitigation measurements, land use) to prevent future problems. Field work and remote sensing data (study of historical aerial photographs and satellite images) were used to understand the geomorphologic evolution and the current processes taking place in an area; this information was used to group the units according to its lithology, dynamic and slope inclination. The map was processed using the geographical information system and categorized in zones of very high, high, moderate, low and null fluvial erosion hazards. The map covers the Metropolitan Area of San Salvador, which is experiencing serious problems of mass wasting processes, collapse and settlements of foundations. Most affected areas belong to the Tierra Blanca Joven tephras which are unsaturated and cover most of the surface; nowadays, the urban projects and infrastructure resting in this material are suffering from extensive damage. The geotechnical information on the tephras shows a decrease in strength and collapsible behavior when saturated. Due to this, the use of Quickdraw tensiometers (suction) and TMS3 (soil moisture content) is proposed for monitoring. The methodology of erosion hazard mapping correlates well with mass wasting reported in the studied area, and for this reason, it could be a good way to protect the natural resources and improve the land use.  相似文献   

A GIS enabled nested simulation-optimization model for routing groundwater to overcome spatio-temporal water supply and demand disconnects in South Texas     

Venkatesh Uddameri  Chandana Kakarlapudi  E. Annette Hernandez 《Environmental Earth Sciences》2014,71(6):2573-2587

Groundwater, under sustainable management policies, can be an invaluable source of water to municipal, agricultural, and industrial sectors. Management, however, can be challenging given that historically, these resources have been privately owned and minimally regulated. This research details the development of a decision support system (DSS) which couples a GIS-based multi-criteria decision-making (MCDM) scheme with simulation-optimization routines to identify suitable regions for groundwater development and optimal preferences for apportioning those supplies to areas of demand in South Texas. The developed DSS consisted of three modules: (1) a GIS-based MCDM for identifying suitable locations for groundwater production; (2) a simulation-optimization model for estimating available groundwater; and (3) a transportation optimization model for redistributing the groundwater. Applying a comprehensive suite of nine exclusionary criteria in GIS resulted in only 15,304 km² (5,909 mi²) suitable for groundwater production out of the original ~50,500 km² (19,500 mi²). Two ideal sites were selected in the suitable region based on proposed major water supply projects in the study area. The projected groundwater extraction rates per month varied considerably over a year emphasizing a need for storage technologies. Furthermore, a transportation optimization model, which considered cost of storage and movement, was developed and applied to obtain the most optimal scheme to transport groundwater from potential supply centers located in Bee and Kennedy counties to projected water deficit areas of San Antonio, Laredo, and McAllen, TX, USA. Lastly, a full-factorial sensitivity analysis was carried out to check the impacts of the supply and demand factors on groundwater production and transport. Policies at the supply centers had a larger impact on the total availability of water, and policies at the demand centers had a larger impact on the total cost of the management scheme. Furthermore, an analysis of total volume stored in a storage and recovery system exhibited an inverse relationship with the groundwater development (supply side) policies and a direct relationship with the demand requirements. The developed DSS proved useful for determining the most optimal siting and distribution network for groundwater sources in South Texas.  相似文献   

SLRS‐5 Elemental Concentrations of Thirty‐Three Uncertified Elements Deduced from SLRS‐5/SLRS‐4 Ratios     

Alexie Heimburger  Mickael Tharaud  Fabrice Monna  Rémi Losno  Karine Desboeufs  Elisabeth B. Nguyen 《Geostandards and Geoanalytical Research》2013,37(1):77-85

The fifth version of natural river water certified reference material, SLRS‐5 (National Research Council – Conseil National de Recherches Canada), is commonly used to control the quality of major and trace element measurements. Concentrations of silicon and thirty‐one uncertified trace elements have been reported for the certified reference material SLRS‐4, but they are not yet available for SLRS‐5. Here, SLRS‐5/SLRS‐4 ratios were deduced from SLRS‐5 and SLRS‐4 measurements by inductively coupled plasma‐atomic emission spectrometry and high‐resolution inductively coupled plasma‐mass spectrometry for certified elements and thirty‐five uncertified elements (rare earth elements, B, Bi, Br, Cs, Ga, Ge, Hf, Li, Nb, P, Pd, Rb, Rh, S, Sc, Si, Sn, Th, Ti, Tl, Y). Both reference materials were measured directly one after the other, so that calculated elemental ratios would not be notably influenced either by calibration uncertainties or by eventual long‐term instrumental drift. The computed ratios are in good agreement with those deduced from the certified values. We also report concentrations for thirty‐three uncertified elements in SLRS‐5 by combining the measured SLRS‐5/SLRS‐4 ratios and the published SLRS‐4 values. The resulting new data set provides target SLRS‐5 values, which will be useful in quality control procedures.  相似文献   

Dynamical consequences of CDM merger trees     

Xavier Hernandez  William H. Lee 《Monthly notices of the Royal Astronomical Society》2004,347(4):1304-1316

  相似文献   

GHASP: A 3-D Survey of Spiral and Irregular Galaxies at Hα     

P. Amram  C. Adami  C. Balkowski  S. Blais-Ouellette  A. Boselli  J. Boulesteix  C. Carignan  V. Cayatte  L. Chemin  J.L. Gach  O. Garrido  O. Hernandez  M. Marcelin  L. Michel-Dansac  H. Plana  D. Russeil  B. Vollmer  H. Wozniak 《Astrophysics and Space Science》2002,281(1-2):393-396

  相似文献   

Using multinomial models to analyse data from Iberian sardine egg incubation experiments: a comparison with traditional techniques     

Bernal  Miguel; Ibaibarriaga  Leire; Lago de Lanzos  Ana; Lonergan  Mike E.; Hernandez  Carmen; Franco  Concha; Rasines  Inmaculada; Valdes  Luis; Borchers  David L. 《ICES Journal of Marine Science》2008,65(1):51-59

  相似文献