Water soluble cations and the fluvial history of mars     

Melvin P. Silverman  Elaine F. Munoz 《Icarus》1975,24(3):383-387

The electrical conductivity and water soluble Na, K, Ca, and Mg of aqueous solutions of terrestrial soils and finely divided igneous and metamorphic rocks were determined. Soils from dry terrestrial basins with a history of water accumulation as well as soils from the topographic lows of valleys accumulated water soluble cations, particularly Na and Ca. These soils as a group can be distinguished from the rocks or a second group of soils (leached upland soils and soils from sites other than the topographic lows of valleys) by significant differences in their mean electrical conductivity and water soluble Na + Ca content. Similar measurements on multiple samples from the surface of Mars, collected by an automated long-range roving vehicle along a highlands to basin transect at sites with morphological features resembling dry riverlike channels, are suggested to determine the fluvial history of the planet.  相似文献   

A Survey for EHB Stars in the Galactic Bulge     

Donald M. Terndrup  Deokkeun An  Angela Hansen  Ruth C. Peterson  Alistair R. Walker  Elaine M. Sadler 《Astrophysics and Space Science》2004,291(3-4):247-252

We present a progress report on an extensive survey to find and characterize all types of horizontal-branch stars in the nuclear bulge of the Galaxy. We have obtained wide, shallow imaging in UBV of ≈12 square degrees in the bulge, with follow-up spectroscopy for radial velocities and metal abundance determinations. We have discovered a number of metal-rich blue HB stars, whose presence in the bulge is expected by the interpretation of the extragalactic ultraviolet excess. Very deep images have been obtained in UBV and SDSS u along the bulge minor axis, which reveal a significant number of EHB candidates fainter than B=19, i.e., with the same absolute magnitudes as EHB stars in several globular clusters.  相似文献   

A search for distant radio galaxies from SUMSS and NVSS – I. Sample definition, radio and K-band imaging     

Carlos De Breuck †  Richard W. Hunstead  Elaine M. Sadler  Brigitte Rocca-Volmerange  Ilana Klamer 《Monthly notices of the Royal Astronomical Society》2004,347(3):837-853

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Effects of elevated CO₂ on the reproduction of two calanoid copepods     

Kristian McConville  Claudia Halsband  Elaine S. Fileman  Paul J. Somerfield  Helen S. Findlay  John I. Spicer 《Marine pollution bulletin》2013

Some planktonic groups suffer negative effects from ocean acidification (OA), although copepods might be less sensitive. We investigated the effect of predicted CO₂ levels (range 480–750 ppm), on egg production and hatching success of two copepod species, Centropages typicus and Temora longicornis. In these short-term incubations there was no significant effect of high CO₂ on these parameters. Additionally a very high CO₂ treatment, (CO₂ = 9830 ppm), representative of carbon capture and storage scenarios, resulted in a reduction of egg production rate and hatching success of C. typicus, but not T. longicornis. In conclusion, reproduction of C. typicus was more sensitive to acute elevated seawater CO₂ than that of T. longicornis, but neither species was affected by exposure to CO₂ levels predicted for the year 2100. The duration and seasonal timing of exposures to high pCO₂, however, might have a significant effect on the reproduction success of calanoid copepods.  相似文献   

Soil CO2 flux baseline in an urban monogenetic volcanic field: the Auckland Volcanic Field, New Zealand     

Agnès Mazot  Elaine R. Smid  Luitgard Schwendenmann  Hugo Delgado-Granados  Jan Lindsay 《Bulletin of Volcanology》2013,75(11):1-9

The Auckland Volcanic Field (AVF) is a dormant monogenetic basaltic field located in Auckland, New Zealand. Though soil gas CO₂ fluxes are routinely used to monitor volcanic regions, there have been no published studies of soil CO₂ flux or soil gas CO₂ concentrations in the AVF to date or many other monogenetic fields worldwide. We measured soil gas CO₂ fluxes and soil gas CO₂ concentrations in 2010 and 2012 in varying settings, seasons, and times of day to establish a baseline soil CO₂ flux and to determine the major sources of and controlling influences on Auckland's soil CO₂ flux. Soil CO₂ flux measurements varied from 0 to 203 g m^?2 day^?1, with an average of 27.1 g m^?2 day^?1. Higher fluxes were attributed to varying land use properties (e.g., landfill). Using a graphical statistical approach, two populations of CO₂ fluxes were identified. Isotope analyses of δ¹³CO₂ confirmed that the source of CO₂ in the AVF is biogenic with no volcanic component. These data may be used to assist with eruption forecasting in the event of precursory activity in the AVF, and highlight the importance of knowing land use history when assessing soil gas CO₂ fluxes in urban environments.  相似文献   

Global geographical databases for modelling trace gas fluxes     

Elaine Matthews 《International journal of geographical information science》2013,27(2):125-142

Abstract

The design and development of global digital databases and their integrated use in studies of terrestrial sources and sinks of trace gases are discussed. Generic design characteristics that expand the utility of these databases are outlined including: hierarchical classification systems that provide for encoding and accessing data at several levels of detail, and fine spatial and thematic resolution which accommodate adaptations to a broad base of applications. The discussion follows the sequence of (1) developing primary databases on major surface characteristics, (2) selectively integrating combinations of data bases to produce secondary data sets of source categories, and (3) combining information on source categories with fluxes to produce tertiary data sets of emissions. These procedures are demonstrated with the example of estimating and evaluating alternative global methane emissions from natural wetlands.  相似文献   

The magnitude and seasonality of aquatic insect subsidies to tropical stream riparia in Hong Kong     

Elaine Y. L. Yuen  David Dudgeon 《Aquatic Sciences - Research Across Boundaries》2016,78(4):655-667

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e-VLBI observations of GHz-peaked spectrum radio sources in nearby galaxies from the AT20G survey     

Paul J. Hancock  Steven J. Tingay  Elaine M. Sadler  Chris Phillips  Adam T. Deller 《Monthly notices of the Royal Astronomical Society》2009,397(4):2030-2036

Gigahertz-peaked spectrum (GPS) radio sources are thought to be young objects which later evolve into Fanaro–Riley type I (FR I) and FR II radio galaxies. We have used the Australia Telescope 20 GHz (AT20G) survey catalogue to select a uniform sample of GPS sources with spectral peaks above 5 GHz, which should represent the youngest members of this class. In this paper, we present e-VLBI observations of 10 such objects which are associated with nearby  ( z < 0.15)  galaxies and so represent a new population of local, low-power GPS sources. Our e-VLBI observations were carried out at 4.8 GHz with the Australia Telescope Long Baseline Array (LBA) using a real-time software correlator. All 10 sources were detected, and were unresolved on scales of ∼100 mas, implying that they are typically less than 100 pc in linear size.  相似文献   

Forest ecosystems, disturbance, and climatic change in Washington State, USA   总被引：2，自引：1，他引：1  

Jeremy S. Littell  Elaine E. Oneil  Donald McKenzie  Jeffrey A. Hicke  James A. Lutz  Robert A. Norheim  Marketa M. Elsner 《Climatic change》2010,102(1-2):129-158

Climatic change is likely to affect Pacific Northwest (PNW) forests in several important ways. In this paper, we address the role of climate in four forest ecosystem processes and project the effects of future climatic change on these processes across Washington State. First, we relate Douglas-fir growth to climatic limitation and suggest that where Douglas-fir is currently water-limited, growth is likely to decline due to increased summer water deficit. Second, we use existing analyses of climatic controls on tree species biogeography to demonstrate that by the mid twenty-first century, climate will be less suitable for key species in some areas of Washington. Third, we examine the relationships between climate and the area burned by fire and project climatically driven regional and sub-regional increases in area burned. Fourth, we suggest that climatic change influences mountain pine beetle (MPB) outbreaks by increasing host-tree vulnerability and by shifting the region of climate suitability upward in elevation. The increased rates of disturbance by fire and mountain pine beetle are likely to be more significant agents of changes in forests in the twenty-first century than species turnover or declines in productivity, suggesting that understanding future disturbance regimes is critical for successful adaptation to climate change.  相似文献   

Influence of solar activity,especially and high altitudes,on theTakata-flocculation-reaction in serum of normal persons     

Kurt R. Reißmann  Konrad Buettner  Elaine A. Topka 《Theoretical and Applied Climatology》1953,5(1):103-111

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