HIDEEP – an extragalactic blind survey for very low column-density neutral hydrogen     

R. F. Minchin  M. J. Disney  P. J. Boyce  W. J. G. de Blok  Q. A. Parker  G. D. Banks †  K. C. Freeman  D. A. Garcia  B. K. Gibson  M. Grossi  R. F. Haynes  P. M. Knezek  R. H. Lang  D. F. Malin  R. M. Price  I. M. Stewart  A. E. Wright 《Monthly notices of the Royal Astronomical Society》2003,346(3):787-802

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Chromospheric synoptic charts for the solar eclipse of November 3, 1994     

Zadig Mouradian  Guillaume Prevot  Germaine Zlicaric  Adriana Galvao Garcia 《Solar physics》1995,158(2):379-381

The synoptic charts of the filaments and active regions near the solar limb are given for the eclipse of November 3, 1994, along with the positions of the prominences. A table helps to associate coronal and chromospheric structures.  相似文献   

Hysteretic energy spectrum and damage control   总被引：1，自引：0，他引：1  

Rafael Riddell  Jaime E. Garcia 《地震工程与结构动力学》2001,30(12):1791-1816

The inelastic response of single‐degree‐of‐freedom (SDOF) systems subjected to earthquake motions is studied and a method to derive hysteretic energy dissipation spectra is proposed. The amount of energy dissipated through inelastic deformation combined with other response parameters allow the estimation of the required deformation capacity to avoid collapse for a given design earthquake. In the first part of the study, a detailed analysis of correlation between energy and ground motion intensity indices is carried out to identify the indices to be used as scaling parameters and base line of the energy dissipation spectrum. The response of elastoplastic, bilinear, and stiffness degrading systems with 5 per cent damping, subjected to a world‐wide ensemble of 52 earthquake records is considered. The statistical analysis of the response data provides the factors for constructing the energy dissipation spectrum as well as the Newmark–Hall inelastic spectra. The combination of these spectra allows the estimation of the ultimate deformation capacity required to survive the design earthquake, capacity that can also be presented in spectral form as an example shows. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   

The use of egg shells to infer the historical presence of copepods in alpine lakes     

Roland Knapp  Jodi Garton  Orlando Sarnelle 《Journal of Paleolimnology》2001,25(4):539-543

Copepods (Class Crustacea, Order Copepoda) are rarely included in paleoecological studies of lakes because they lack long-lasting exoskeletal remains. We describe the remains of eggs (egg shells) from Hesperodiaptomus copepods that are well preserved and abundant in alpine lake sediments. We demonstrate that the egg shells are the remains of Hesperodiaptomus eggs based on (i) the similar size and morphology of egg shells collected from sediments and those produced from the hatching of eggs obtained from laboratory-maintained Hesperodiaptomus, and (ii) the finding that diapausing eggs collected from lake sediments and hatched in the laboratory produced copepod nauplii that were morphologically indistinguishable from those hatched from eggs produced by laboratory-maintained Hesperodiaptomus. Egg shells were approximately two orders of magnitude more abundant in sediment cores than were viable diapausing eggs, making egg shells superior to viable diapausing eggs for quantifying the historical presence and abundance of Hesperodiaptomus. These results have important implications for alpine lake restoration as egg shells can be used to identify lakes in which Hesperodiaptomus was eliminated by fish introductions but has failed to return after fish eradication, lakes in which the pre-disturbance conditions are likely to be restored only by reintroductions of this important taxon.  相似文献   

FLR: an open-source framework for the evaluation and development of management strategies   总被引：1，自引：3，他引：1  

Kell  L. T.; Mosqueira  I.; Grosjean  P.; Fromentin  J-M.; Garcia  D.; Hillary  R.; Jardim  E.; Mardle  S.; Pastoors  M. A.; Poos  J. J.; Scott  F.; Scott  R. D. 《ICES Journal of Marine Science》2007,64(4):640-646

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Pleistocene Charophyta from Arroyo Perucho Verna,Province of Entre Rios,Argentina     

Adriana Garcia 《Journal of Paleolimnology》1994,10(1):53-58

The Pleistocene charophytes from Arroyo Perucho Verna, Province of Entre Ríos, were analyzed.Chara contraria Br. ex Kütz.,C. contraria var.longilinea Cáceres,C. globularis Thuill. andTolypella intricata (Trent. ex Roth.) Leonh. var.apiculata (A. Br.) Wood were described and illustrated with scanning electron microscope. The assemblage indicates fresh alkaline to slightly saline waters, not very deep, in a lentic or sometimes lotic environment. Extant assemblages provide data for this paleoecological reconstruction.This is the sixth in a series of papers published in this issue on Paleolimnology in Southern South America. Dr. C. A. Fernandéndez served as guest editor for these papers.  相似文献   

Stereoscopic measurements of flares from PHOBOS and GOES     

Howard A. Garcia  František Fárník 《Solar physics》1991,131(1):137-148

A unique approach to observing the Sun stereoscopically in soft X-rays was afforded by the PHOBOS mission to Mars during 1989. Concurrent measurements of two flares from two widely separated spacecraft allowed us to obtain estimates of each flare's height above the solar surface. The requirement was that the flare had to be over the limb as observed by one spacecraft and on the visible disk as viewed by the other. The first flare occurred on March 4, when the active region was beyond the east limb as observed by GOES (at Earth), but on the disk as viewed by PHOBOS (at Mars). The second flare, on March 15, was on the disk for GOES, but beyond the west limb for PHOBOS. We believe that the same extraordinary active region, 5395, was responsible for both events. Soft X-ray photometers on each spacecraft contained two broad-band channels. The two-channel data were used to computeflare (assumed isothermal) plasma temperatures. The sharply peaked flare on March 4 indicated essentially identical maximum electron temperatures ( 13 Mk) at both spacecraft, confirming that the hottest plasma was indeed concentrated at the highest (unocculted) part of the loop. However, in the case of the long-duration March 15 flare, whose loop was in apparent upwards motion, the partially occulted flare indicated substantially cooler temperatures. This finding suggests that the hot core of this flare may have been below the limb, or that the partially occulted flux originated not from post-flare loops but from an independent, higher X-ray arch. The PHOBOS and GOES X-ray photometers were intercompared in July 1988, soon after the PHOBOS launch, to establish relative calibration parameters.  相似文献   

Automated astrographic plates measuring process     

A. López Garcia  J. L. Valdés Navarro  J. A. López Orti  R. López Machi 《Astrophysics and Space Science》1990,171(1-2):289-292

The astrographic plates measuring process applied at the Astronomical Observatory of Valencia has been described.The measure of astrographic plates of our minor planets observation programme has been carried out by means of a binocular microscope with a photometer, held by a personal computer through an interface. The process of measure in each position of the plate holder is automated, once two stars are selected and the sequence of the objects to be measured is defined.The process will be improved in the next future, by the substitution of the searching device (a photometer) by a CCD camera plus a digitizer board.Paper presented at the 11th European Regional Astronomical Meetings of the IAU on New Windows to the Universe, held 3–8 July, 1989, Tenerife, Canary Islands, Spain.  相似文献   

A search for new objects in the transition phase between AGB-stars and planetary nebulae     

A. Manchado  P. Garcia Lario  S. R. Pottasch 《Astrophysics and Space Science》1989,156(1-2):57-62

We present the first results of a spectroscopy survey of iras sources with colours similar to those of planetary nebulae.Two new planetary nebulae, some H emission line stars, one peculiar source which is probably a pre-Main-Sequence object and a new Seyfert I galaxy have been found.Based on observations collected at the European Southern Observatory, La Silla, Chile.  相似文献   

Hydrogeochemical and Flow Modeling of Aquitard Percolation in the Cariri Valley-Northeast Brazil     

Carlos José Freire Machado  Maria Marlúcia Freitas Santiago  Luiz Alberto Ribeiro Mendonça  Horst Frischkorn  Josué Mendes Filho 《Aquatic Geochemistry》2007,13(2):187-196

Flow modeling and hydrogeochemical inversion calculations were performed on the aquifer systems of the Crato-Juazeiro Graben in the Araripe Sedimentary Basin of the Cariri Valley, Northeast Brazil, in order to assess aquifer interconnections through an aquitard of the Araripe Plateau. Steady state hydraulic head numeric calculations with the finite difference method used Modflow software with hydrologically based boundary conditions and a piezometric surface as initial condition. Hydrogeochemical inversion with PHREEQC was performed for two water samples representing typical initial and final waters along the flow path. Flow simulation shows that approximately 20% of all recharge water from the superior aquifer system passes through the Santana aquitard reaching the middle aquifer system. Quantification of mineral dissolution/precipitation processes, ion exchange and microbiological redox reactions taking place in the aquifer systems also indicates hydraulic interconnection of the superior and middle aquifer systems through the Santana aquitard.  相似文献