Experimental investigation of the scavenging of gaseous mercury by sea salt aerosol     

Elizabeth G. Malcolm  Amanda C. Ford  Tara A. Redding  Matthew C. Richardson  Brianna M. Strain  Scott W. Tetzner 《Journal of Atmospheric Chemistry》2009,63(3):221-234

Sea salt aerosol may be an important sink for reactive gaseous mercury (RGM) in the marine boundary layer, reducing ambient RGM concentrations and transferring the mercury (Hg) to the oceans and coastal ecosystems. The goal of this study was to determine the affinity of gaseous mercury for sea salt aerosol (SSA) by conducting adsorption experiments with sea salt-coated sampling denuders. In the first set of experiments, ambient outdoor air was passed through denuders coated with either KCl, as in the widely accepted method to sample RGM, or with NaCl, a primary component of sea salt aerosols. On the one sampling day in which RGM was above the MDL, the NaCl coated denuders removed Hg from the ambient air, equivalent to 87% of the RGM in the air (as determined by KCl denuders). For the second set of experiments HgCl₂ generated in the laboratory was passed through denuders coated with KCl and either NaCl or sea salt. The NaCl denuders collected an average of 99 ± 16% of the mercury that the KCl denuders collected. Newly coated sea salt denuders collected 88 ± 17% of the amount of mercury that the KCl denuders collected, but interestingly the sea salt denuders capacity decreased with repeated use. These experiments demonstrate that HgCl₂, a major component of RGM has a strong affinity for NaCl and sea salt and is therefore likely to be scavenged by SSA. This study adds to the growing evidence that RGM is scavenged by sea salt aerosols and therefore more quickly deposited to the ocean and coastal environment.  相似文献   

Geographical and structural change in nursing care provision for older people in England, 1993-2001     

Robert G. Ford  Geoffrey C. Smith 《Geoforum》2008,39(1):483-498

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RAISED MARINE TERRACES ALONG THE GULF OF ADEN COAST OF SOMALIA     

George A. Brook  James B. Cowart  Derek C. Ford 《自然地理学》2013,34(4):297-312

Mapping in the Galweda-Elayu area of northern Somalia has revealed depositional and erosional marine terraces at elevations of approximately 16 m, 8 m, and 2 m. These terraces vary from 0–2300 m, 200–2200 m, and 0–800 m in width, respectively. Sediments exposed in stream-valley walls demonstrate that the two higher terraces were formed by marine transgressions followed later by regressions to below present sea level. Beach ridges on the terraced alluvial fan at the mouth of togga Galweda imply that sea level and/or land elevation varied by at least 6 m during the formation of the 16-m terrace and by at least 3 m during the formation of the 8-m terrace. ²³⁰Th/²³⁴U ages of corals suggest that the 8-m terrace was formed during deep-sea isotope substage 5c (105 kyr B.P.) and the 2-m terrace during substage 5a (80 kyr B.P.). A 7-kyr-old coral from above the present storm beach on the outer flanks of the 2-m terrace suggests that sea level in the Gulf of Aden was close to its present level by the middle Holocene. No material suitable for dating was recovered from the 16-m terrace, but on morphological grounds and based on marine-terrace elevations elsewhere in the Red Sea-Gulf of Aden rift zone, we believe that the 16-m terrace was formed during isotope substage 5e (132–120 kyr B.P.), when global sea level was about 6 m above present.  相似文献   

Elemental abundances in the Blanco 1 open cluster     

A. Ford  R. D. Jeffries  B. Smalley 《Monthly notices of the Royal Astronomical Society》2005,364(1):272-282

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Investigation of MgO as a candidate for the primary nucleating dust species around M stars     

Jayesh S. Bhatt †  Ian J. Ford 《Monthly notices of the Royal Astronomical Society》2007,382(1):291-298

The possibility of magnesium oxide being the first species to nucleate in the cooling outflows around M stars has been investigated. By treating the formation of the seed nuclei as a homogeneous nucleation problem and using molecular dynamics data obtained with the 'compressible ion potential' for MgO, free energy calculations are performed to obtain an estimate of the population densities of MgO clusters of various sizes. It is found that a free energy barrier of at least hundreds of   k _B T   would need to be climbed in order for MgO to nucleate in significant amount in typical circumstellar shells, hence ruling out MgO as a realistic candidate for the primary nucleating dust species. This is in agreement with a similar conclusion reached in earlier studies, although the present calculations are based on a much more robust potential model for MgO.  相似文献   

National-level factors affecting planned,public adaptation to health impacts of climate change     

A.C. Lesnikowski  J.D. Ford  L. Berrang-Ford  M. Barrera  P. Berry  J. Henderson  S.J. Heymann 《Global Environmental Change》2013,23(5):1153-1163

Our understanding of whether adaptive capacity on a national level is being translated into adaptation policies, programs, and projects is limited. Focusing on health adaptation in Annex I Parties to the UNFCCC, we examine whether statistically significant relationships exist between regulatory, institutional, financial, and normative aspects of national-level adaptive capacity and systematically measured adaptation. Specifically, we (i) quantify adaptation actions in Annex I nations, (ii) identify potential factors that might impact progress on adaptation and select measures for these factors, and (iii) calculate statistical relationships between factors and adaptation actions across countries. Statistically significant relationships are found between progress on adaptation and engagement in international environmental governance, national environmental governance, perception of corruption in the public sector, population size, and national wealth, as well as between responsiveness to health vulnerabilities, population size and national wealth. This analysis contributes two key early empirical findings to the growing literature concerning factors facilitating or constraining adaptation. While country size and wealth are necessary for driving higher levels of adaptation, they may be insufficient in the absence of policy commitments to environmental governance. Furthermore, governance and/or incentive frameworks for environmental governance at the national level may be an important indicator of the strength of national commitments to addressing health impacts of climate change.  相似文献   

Intersexuality in crustaceans: genetic, individual and population level effects   总被引：1，自引：0，他引：1  

Ford AT  Sambles C  Kille P 《Marine environmental research》2008,66(1):146-148

Scientists investigating toxicants such as endocrine disrupting chemicals (EDCs) at the cellular at the sub-cellular level are often faced with criticisms as to how these effects can be extrapolated to the level of individuals and their populations. This report aims to provide an overview of the studies undertaken on crustacean model, Echinogammarus marinus LEACH (AMPHIPODA), and intersex phenotypes, at the individual and population levels, and provide additional emergent data at the genomic level. These, normal and intersex, males and females have been investigated by cross-hybridisation microarray analysis and specific sexually dimorphic genes and corresponding properties identified between each sexual phenotype. The morphology, physiology and histology of these intersexes have been investigated in detail and a number of reproductive costs have been identified including reduced fecundity and fertility. These costs have been incorporated into a population model and simulated over a ten-year period to ascertain how different levels of intersexuality affect the stability of populations. Based on the information gained through study of intersex models (with known endocrine dysfunction) together with the substantial quantity of historical data relating to effects of chemicals on amphipod fecundity, growth and mortality, the development of appropriate biomarkers is nearer to being assessed from the level of genes to that of the population.  相似文献   

Molluscan assemblages from archaeological deposits     

Pamela J. Ford 《Geoarchaeology》1989,4(2):157-173

Research about the impact of prehistoric human subsistence strategies upon prey populations of shellfish is based on the assumption that trends in shell size are directly related to collection strategies. A shell midden on San Juan Island, Washington, where archaeological research is sponsored by the University of Washington and hosted by the National Park Service, provides large samples of shells from separate archaeological deposits. the shells from each deposit produce size-frequency distributions that vary in shape (modality). Because several factors (the original prey population, the method of collection and transport, the environment of deposition, and post-depositional processes) affect the size-frequency distribution differentially, the shell measurements do not provide the direct archaeological information expected.  相似文献   

Practical Implementation of Random Forest-Based Mineral Potential Mapping for Porphyry Cu–Au Mineralization in the Eastern Lachlan Orogen,NSW, Australia     

Ford  Arianne 《Natural Resources Research》2020,29(1):267-283

Natural Resources Research - With the increasing use of machine learning for big data analytics, several methods have been implemented for the purpose of exploration targeting using mineral...  相似文献   

DARWIN GLASS AND DARWIN CRATER: A PROGRESS REPORT     

R.F. Fudali  R.J. Ford 《Meteoritics & planetary science》1979,14(3):283-296

Tasmanian Darwin glass has a fusion age sensibly identical with that of Australasian tektites and it is reasonable to assume all were produced in the same event. Recently a number of new Darwin glass localities and an associated crater have been discovered. The glass stewnfield covers at least 400 km² and there is a strong positive correlation between glass fragment size and abundance and proximity to the crater. The glass was distributed from some point near the crater, with the smallest pieces traveling furthest. This structure is apparently an impact crater of rather unusual configuration and fortuitous location. Our gravity survey reveals a closed sedimentary basin about 1000 meters in diameter. A centrally located drill hole penetrated 60 meters of lacustrine clays and 40 meters of mixed clay, sand and rock fragments. The hole was terminated at 100 meters in loose sand containing sand-sized fragments of Darwin glass and lechetelierite. The 100 meters of cored sediments accounts for only about half of the observed 3.5 milligal negative anomaly and there must be a substantial additional thickness of low density material at depth. Further drilling is essential to confirm an impact origin and to delineate the subsurface crater configuration. This information would be of great calibration value for theoretical modeling studies of explosive cratering. The Darwin strewnfield characteristics support the theory that the distribution of Australasian tektites was aided by an impact-generated, atmospheric blast wave (or waves). The stratigraphic position of glass below 100 meters of lake sediments is strong evidence that the postulated stratigraphic age of the Australian land tektites is incorrect.  相似文献