American Geography and Geographers: Toward Geographical Science          下载免费PDF全文

Ron Johnston 《Geographical review》2017,107(3):e24-e28

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The magnetotelluric sounding method | A.A. Kaufman and G.V. Keller, 1981. Methods in Geochemistry and Geophysics, 15. Elsevier,Amsterdam, xiv + 596 pp., US$144.00, Dfl.295.00     

V.R.S. Hutton 《Earth》1983,19(4):352-353

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A magneto-telluric deep crustal study in south-central Portugal     

A. Correia  F. W. Jones  G. K. Dawes  V. R. S. Hutton 《Studia Geophysica et Geodaetica》1993,37(4):331-344

Summary A geothermal anomaly reported to exist in southern Portugal and with heat flow density values as high as 160 mW/m² was studied by the magneto-telluric method. The results of the magneto-telluric survey indicate that the study area is divided into several high electrical resistivity, deep-rooted blocks separated by low electrical resistivity zones. These latter zones coincide with the main trends of the faults that cross the region. The high heat flow density values reported for the area are incompatible with the high electrical resistivities observed in the magneto-telluric survey. Furthermore, heat production values calculated for some of the rocks that crop out in the area of the geothermal anomaly cannot explain the high heat flow density valuss. Since no hydrothermal activity is known for the region and recent volcanism is absent, it is suggested that previous heat flow density calculations for the area covered by the magnetotelluric survey are overestimated.Presented at International Meeting on Terrestrial Heat Flow and the Structure of Lithosphere, Bechyn Castle, Czech Republic, September 2 – 7, 1991.  相似文献   

Time-dependent neutrino transport out of dense stellar cores     

I. Lichtenstadt  A. Ron  N. Sack  J. J. Wagschal  S. A. Bludman 《Astrophysics and Space Science》1980,71(1):219-227

Time-dependent neutrino transport out of an optically thick neutronized stellar core is calculated to study the effects of neutrino degeneracy and of source depletion. Neutrino trapping inhibits further neutrino emission until neutrinos peel out of the outer zones of the core, exposing successively inner zones. This inwardly propagating neutrino rarefaction wave can lead toe ^–+pv+n oscillations in chemical composition. The effect of neutrino Fermi statistics is to retard considrably and disperse neutrino leakage out of the core, making neutrino transport insignificant during fast stages of core collapse.Supported in part by the U.S. Department of Energy under Contract EY-76-C-02-3071.  相似文献   

Relationship of Water Chemistry to Serum ThyroidHormones in Captive Sharks with Goitres     

Gerald L. Crow  Marlin J. Atkinson  Benny Ron  Shannon Atkinson  Arleene D. K. Skillman  George T. F. Wong 《Aquatic Geochemistry》1998,4(3-4):469-480

Captive whitetip reef sharks, Triaenodon obesus,at Sea Life Park (SLP) Hawaii, Waimanalo, Hawaii develop goitre, whereas, T. obesus at the Waikiki Aquarium (WAQ), Honolulu,Hawaii do not develop goitre. To determine theeffects of natural concentrations of iodine on thereduction of goitre, two sharks from SLP with goitrewere placed in an enclosed coastal lagoon with naturalseawater. Using ultrasound measurements the twogoitres were initially 11.4 cm and 14.6 cm in depthand after 3 months decreased to 4.7 cm and 5.7 cm. Radioimmunoassay analysis of the thyroid hormoneT3 sera concentrations were initially 0.22 ng/mland 0.33 ng/ml and increased to 1.84 ng/ml after beingplaced in the lagoon. Sera T4 were initially0.93 ng/ml and 0.99 ng/ml and increased dramaticallyto 17 ng/ml and 56 ng/ml. Over the six month samplingperiod, two resident sharks in the lagoon with normalthyroids had sera T3 concentrations from 0.89ng/ml to 1.1 ng/ml, and sera T4 concentrationsfrom 3.1 ng/ml to 7.9 ng/ml. The hypothyroidcondition in the SLP goitred-sharks is likely linkedto the low environmental iodide (<0.005 M), andhigh nitrate (111 M) of SLP water. The WAQwell-water facility was characterized by anoxic waterwith high iodide (0.60 M), total iodine (1.90M), and typical nitrate (24.6 M)concentrations of interstitial groundwater. Thedifference of iodide concentration of SLP and WAQ tankwater (<0.005 M versus 0.60 M) wasdirectly related to the hydrogeology of the well-watersources. To avoid goitre in marine aquarium systems,we recommend maintaining iodide concentrations of atleast 0.15 M.  相似文献   

Relative potency of PAHs and heterocycles as aryl hydrocarbon receptor agonists in fish   总被引：6，自引：0，他引：6  

Barron MG  Heintz R  Rice SD 《Marine environmental research》2004,58(2-5):95-100

The relative potency of polycyclic aromatic compounds as aryl hydrocarbon receptor (AhR) agonists in fish was determined using data on CYP1A induction or AhR binding for 74 polycyclic aromatic hydrocarbons (PAHs) and heterocycles in teleost, avian, or mammalian systems from 18 published papers. Each PAH was assigned a fish potency factor relative to the potency of 2,3,7,8-tetrachlorodibenzo-p-dioxin as an AhR agonist. Two and three ring unsubstituted PAHs were generally inactive in fish, avian, and mammalian systems. Benzo[k]fluoranthene and indeno[1,2,3-cd]pyrene were consistently the most potent PAHs, with fish potency factors of 0.001-0.002. Common structural features associated with higher potency PAHs included 4-6 rings containing fluoranthene or phenanthrene structures with an exposed bay region. These results show that PAHs can have similar potency as many dioxin-like PCBs, and AhR mediated toxicity should be considered in assessing the risks of PAHs in fish.  相似文献   

Development and evaluation of catch per unit effort indices for southern blue whiting (Micromesistius australis) on the Campbell Island Rise, New Zealand   总被引：1，自引：0，他引：1  

Hanchet  Stuart M.; Blackwell  Ron G.; Dunn  Alistair 《ICES Journal of Marine Science》2005,62(6):1131-1138

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Predicting the effects of area closures and fishing effort restrictions on the production, biomass, and species richness of benthic invertebrate communities   总被引：3，自引：0，他引：3  

Hiddink  J.G.; Hutton  T.; Jennings  S.; Kaiser  M.J. 《ICES Journal of Marine Science》2006,63(5):822-830

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Modelling fishing location choice within mixed fisheries: English North Sea beam trawlers in 2000 and 2001   总被引：1，自引：2，他引：1  

Hutton  Trevor; Mardle  Simon; Pascoe  Sean; Clark  Robin A. 《ICES Journal of Marine Science》2004,61(8):1443-1452

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Leadership in American Academic Geography: The Twentieth Century Michael S. DeVivo. Lexington Books,Lanham, 2015, pp. xiv + 211 (ISBN 978‐0‐7391‐9912‐1) (hbk).          下载免费PDF全文

Ron Johnston 《Singapore journal of tropical geography》2016,37(2):269-271

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