The global distribution of O₃ on mars     

T.Y. Kong  M.B. McElroy 《Planetary and Space Science》1977,25(9):839-857

Models are developed to describe the photochemistry of ozone on Mars. Catalytic reactions involving H, OH and HO₂ play a major role at low latitudes where they ensure a vertical column density for O₃ of less than 2 × 10^?4 cm atm. The source for odd hydrogen (H + OH + HO₂) is relatively smaller at high latitudes in winter due to the small concentrations of H₂O present there at that time. Odd hydrogen is also efficiently removed from the high-latitude winter atmosphere by condensation of H₂O₂. The role of catalytic chemistry is reduced accordingly and the vertical column density of O₃ may be as large as 5.7 × 10^?3 cm atm in accord with earlier observations carried out by Barth and co-workers with instruments on Mariner 9.  相似文献   

Photoelectrons in the upper atmosphere: A formulation incorporating effects of transport     

Michael J. Prather  Michael B. McElroy  Jose Rodriguez 《Planetary and Space Science》1978,26(2):131-138

An efficient scheme is described for computation of photoelectron energy spectra. The method, similar to one used in radiative transfer theory, incorporates effects due to spatial and angular redistribution of electrons. These effects play a dominant role at heights above 400 km.  相似文献   

Data,dispossession, and Facebook: techno-imperialism and toponymy in gentrifying San Francisco     

Erin McElroy 《Urban geography》2019,40(6):826-845

ABSTRACT

This article situates the 2015 rebranding of Zuckerberg San Francisco General within San Francisco’s technopolitical landscape. After Facebook’s CEO Mark Zuckerberg donated to the hospital, thereby acquiring naming rights, local toponymical tension percolated. This was in part due to Facebook’s gentrifying role in the city and the racial violence such processes constitute, as well as ongoing practices data colonialism. The latter includes Facebook’s attempt at pairing hospital data with user data in order to augment its scope into intimate and bodily geographies. In exploring the intertwining of gentrification and data colonialism, here I forge the concept of techno-imperialism as an analytic and as a point of departure in understanding Facebook’s multi-scalar impacts. As I suggest, the transformation of “The General” to “The Zuckerberg” indexes the company's techno-imperiality, as well as its efforts to mask its dispossessive impacts.  相似文献   

Genomic resources for the spotted ragged-tooth shark Carcharias taurus     

JD Klein  AE Bester-van der Merwe  ML Dicken  A Emami-Khoyi  KL Mmonwa 《African Journal of Marine Science》2019,41(1):115-118

Genomic data can be a useful tool in the management and conservation of biodiversity. Here, we report the development of genomic resources for the spotted ragged-tooth shark Carcharias taurus using genome-wide DNA data from Illumina next-generation sequencing. We explored two commonly used genetic marker types: microsatellites and mitochondrial DNA. A total of 4 394 putative microsatellites were identified, of which 10 were tested on 24 individuals and found to have ideal properties for population genetic analyses. Additionally, we reconstructed the first complete mitochondrial genome of a South African spotted ragged-tooth shark, and highlight the most informative gene regions to facilitate future primer design. The data reported here may serve as a resource for future studies and can ultimately be applied in the sustainable conservation and fisheries management of this apex predator.  相似文献   

Introduction to the Special Issue of Atmosphere-Ocean—Proceedings of the Twenty-Second QOS / Introduction du numéro spécial d'Atmosphere-Ocean – Comptes-rendus du vingt-deuxième SQO     

C.T. McElroy 《大气与海洋》2015,53(1):1-6

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Design, Installation, and Uses of Combination Ground Water and Gas Sampling Wells     

Joel M. Hubbell  Thomas R. Wood  Brian Higgs  Allan H. Wylie  Deborah L. McElroy 《Ground Water Monitoring & Remediation》1998,18(3):151-157

Waste disposal sites with volatile organic compounds (VOCs) frequently contain contaminants that are present in both the ground water and vadose zone. Vertical sampling is useful where transport of VOCs in the vadose zone may effect ground water and where steep vertical gradients in chemical concentrations are anticipated. Designs for combination ground water and gas sampling wells place the tubing inside the casing with the sample port penetrating the casing for sampling. This physically interferes with pump or sampler placement. This paper describes a well design that combines a ground water well with gas sampling ports by attaching the gas sampling tubing and ports to the exterior of the casing. Placement of the tubing on the exterior of the casing allows exact definition of gas port depth, reduces physical interference between the various monitoring equipment, and allows simultaneous remediation and monitoring in a single well. The usefulness and versatility of this design was demonstrated at the Idaho National Engineering and Environmental Laboratory (INEEL) with the installation of seven wells with 53 gas ports, in a geologic formation consisting of deep basalt with sedimentary interbeds at depths from 7.2 to 178 m below land surface. The INEEL combination well design is easy to construct, install, and operate.  相似文献   

Tectonic and Topographic Framework of Political Division     

Brandon J. McElroy  Bruce H. Wilkinson  Edward D. Rothman 《Mathematical Geology》2005,37(2):197-206

Boundaries between the various topographic, geologic, and socio-political entities that span the Earths continental surfaces are determined by a myriad of complexly interrelated natural and/or cultural factors. Areas of large river basins, of lithologic units on geologic maps, and of nations exhibit size frequency distributions that are closely approximated by density functions in which diameters of individual areas are distributed exponentially. As such, size distributions of each type of surface unit are closely modeled as randomly delimited areas. In other words, if one were to walk in a straight line across any particular continent, each step along that transect would embody some random continuous probability of passing out of a major drainage basin, or out of an area of more or less homogeneous rock type, or from one country to another. Moreover, this simple truism gives rise to area frequency distributions for large river basin or outcrop or nation area that are primarily dependent on the number of basins or outcrops or countries that exist across that particular landmass. As a consequence, the size frequencies of these areal units can be closely predicted knowing only the total area under consideration and the number of drainage basins, outcrop areas, or nations that exist within the area. The similarity between area frequencies of large river basins and rock types and nations suggests a nontrivial component of geologic influence on the partitioning of continental surfaces into major political divisions, and implies that cultural and economic factors, which serve to divide and unite political entities, do so within a geological framework.  相似文献   

Packaging the Falklands     

J.K. McElroy 《Marine Policy》1983,7(2):124-125

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Effects of sewage-impacted sediment on reproduction in the benthic crustacean Leptocheirus plumulosus     

Zulkosky AM  Ferguson PL  McElroy AE 《Marine environmental research》2002,54(3-5):615-619

Several organic contaminants in sewage effluent have been shown to elicit an estrogenic response in juvenile fish. Comparatively little emphasis has been placed on assessing these effects in marine invertebrates, particularly benthic organisms inhabiting sediment where lipophilic contaminants tend to persist. The present study examined reproductive effects in the benthic crustacean Leptocheirus plumulosus exposed to sewage-impacted sediment from Jamaica Bay, New York. Data from chronic 28-day tests showed a 50% reduction in the average number of young (juveniles + embryos) produced per surviving female in exposures to sediment from Jamaica Bay (JB). Nonylphenol ethoxylate ('NPEO) concentrations at this site were measured at 44.2 microg/g dw, concentrations two orders of magnitude higher than reference site concentrations in central Long Island Sound (CLIS). Dose-response studies with nonylphenol (NP) amended reference sediment, however, did not significantly affect reproduction suggesting that other contaminants may have contributed to the effects observed.  相似文献   

In vivo metabolism of benz[a]anthracene by the polychaete Nereis virens     

Anne E. McElroy   《Marine environmental research》1985,17(2-4)

Polycyclic aromatic hydrocarbons (PAH) can be metabolically activated to reactive intermediates with mutagenic potential. Although marine sediments serve as the major repository for PAH released into the environment, little is known of the capabilities of benthic organisms, particularly infaunal invertebrates to metabolize PAH.¹ In this study, in vivo metabolism of of the PAH benz[a]anthracene (BA) by the polychaete Nereis virens was investigated. Worms maintained in flow-through benthic microcosms were exposed to [¹⁴C-12]-BA sorbed to sediment, introduced directly to the water column, and in labeled food for periods of 4 to 25 days. Regardless of mode of exposure, most radiolabel recovered from Nereis was present as metabolic products with only 2 to 23% remaining as parent compound. In addition, a significant proportion (from 33 to 51%) of accumulated radioactivity was neither solvent extractable nor water soluble, suggesting that incorporation into macromolecular pools is a major fate of accumulated BA in Nereis virens.  相似文献