Tribute to John Wasson     

Ed Anders  Derek Sears 《Meteoritics & planetary science》1992,27(1):2-2

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Variations in the Rate of Anaerobic Succinate Accumulation within the Central and Marginal Regions of an Euryoxic Bivalve Mantle     

Ed  Greenfield Miles A.  Crenshaw 《Marine Ecology》1981,2(4):353-362

Abstract. Anaerobic metabolism in the central and marginal portions of the mantle of Mercenaria mercenaria was compared. Anaerobic succinate accumulation was more rapid in the central region. This difference may be due to higher phosphoenolpyruvate carboxykinase activity in the central region. Thus, the central region is more specialized for anaerobic metabolism and the marginal region more for net shell growth. The original rate of succinate accumulation in the mantle is similar in isolated mantles and intact clams, suggesting that mantle succinate production does not require translocation of precursors from other tissues. However, in intact clams, the rate of succinate accumulation in the central region of the mantle slows after four hours. The reduced rate is probably caused by reducing the metabolic rate. Succinate accumulation and shell dissolution are slower in freshly collected clams than in clams that had been stored anaerobically. The difference may be due to induction of PEPCK synthesis during storage. Shell derived calcium did not accumulate in the mantle and, therefore did not alter the intracellular calcium concentration in the mantle.  相似文献   

The Ah receptor in marine animals: phylogenetic distribution and relationship to cytochrome P4501A inducibility     

Mark E. Hahn  Alan Poland  Ed Glover  John J. Stegeman 《Marine environmental research》1992,34(1-4)

In mammals, the induction of cytochrome P4501A forms by chlorinated dibenzo-p-dioxins, chlorinated dibenzofurans, and halogenated biphenyls is under control of a soluble protein known as the Ah (aromatic hydrocarbon) receptor. Little is known about the presence and properties of the Ah receptor in other vertebrate and invertebrate species. In these studies, we sought evidence for an Ah receptor in the liver or liver-equivalent of 20 species of marine and freshwater animals, using the photoaffinity ligand 2-azido-3-[¹²⁵I] iodo-7,8-dibromodibenzo-p-dioxin (N₃[¹²⁵I]Br₂DD). Specific labeling of cytosolic proteins by N₃[¹²⁵I]Br₂DD was observed in seven species of teleost and elasmobranch fish, in PLHC-I fish hepatoma cells, and in beluga whales. No specifically labeled proteins were found in cytosol from two species of agnathan fish nor in any of nine invertebrate species representing eight classes of four phyla. The presence or absence of specifically labeled polypeptides corresponds with the inducibility of cytochrome P4501A and sensitivity to the toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin and related planar halogenated aromatic hydrocarbons in many of these groups. Thus, Ah receptor function may have arisen early invertebrate evolution and has been conserved from elasmobranch and teleost fish to mammals.  相似文献   

The effects of sewage discharge on water quality and phytoplankton of Hawai'ian coastal waters     

Parnell PE 《Marine environmental research》2003,55(4):293-311

The effects of sewage discharge on algal populations and the quality of Hawai'ian coastal waters were investigated. Two outfalls were studied. One discharges primary treated sewage and the other discharges secondary treated sewage but are otherwise similar. This enabled comparisons of the effects of these different levels of treatment on the water quality and algal productivity of receiving waters. Plumes were followed and repeatedly sampled in a time-series manner. Rhodamine dye was used as a conservative tracer to compare the dilution behavior of the plume constituents MRP, NO(3)+NO(2), NH(4), Silicate, TDP, TDN, total bacteria, PC, and PN. Rates of initial dilution ranged from two to almost three orders of magnitude, and were in reasonable agreement with engineering model predictions. Dilution of plume constituents approximated that of Rhodamine until background concentrations were reached, typically within 10 min of discharge. Chl a concentrations did not increase through time in the primary sewage plume but did increase up to 30% in the secondary sewage plume. However, rates of far-field dilution were so rapid that the increase could not have been due to algal growth. The increase was attributed to the plume mixing with a water mass whose relative chl a concentrations were greater. Rates of secondary dilution ranged from 2 to 3 orders of magnitude resulting in total dilutions of 10(5)-10(6) within 3 h of discharge. These rates of secondary dilution were much greater than model predictions. From a nutrient standpoint, secondary treatment exhibited no advantages over primary treatment because dilutions were so rapid.  相似文献   

Beyond world cities: Central America in a global space of flows   总被引：1，自引：0，他引：1  

Ed Brown  Peter J. Taylor  & Gilda Catalano 《Area》2002,34(2):139-148

Central America is a region without a world city. Traditionally, the region's national projects have been based upon openness to the world economy: how do the region's contemporary transnational projects connect to the world economy under the new conditions of openness that is contemporary globalization? Focusing upon advanced producer services, three connections into the world city network are identified: global service firms operating directly in Central American cities, local service firms operating indirectly through extra-regional world cities and global service firms operating through Latin American regional offices. Miami is confirmed as the primary world city through which Central America connects into the world economy  相似文献   

Precambrian–Cambrian boundary interval deposition and the marginal platform of the Avalon microcontinent     

Ed Landing   《Journal of Geodynamics》2004,37(3-5):411

Thick terminal Proterozoic–lowest Cambrian successions allow reference of the Saint John, New Brunswick, and MacCodrum Brook, southern Cape Breton Island, areas to the marginal platform of the Avalon microcontinent. Marginal-platform siliciclastic-dominated sequences form a cover on Late Precambrian arc successions from southern New Brunswick to North Wales. Their deposition in fault-bounded basins began with the origin of the Avalon microcontinent and development of a persistent transtensional regime in the latest Precambrian. The terminal Proterozoic–lowest Cambrian on the Avalonian marginal platform consists of three successive lithofacies associations: lower subaerial rift to marginal-marine facies; overlying cool-water, wave-influenced, marine platform sandstones and shales; and higher macrotidal quartz arenites (=Avalonian depositional sequences 1–2). Only the Lower Cambrian macrotidal quartz arenites onlap southeast, where they form the oldest Cambrian unit on the inner platform. These major lithofacies are the Rencontre, Chapel Island, and Random formations, respectively, in Avalonian North America. Southwest thinning of the Rencontre–Chapel Island–Random interval in southern New Brunswick reflects slower subsidence of a fault-bounded area in the city of Saint John. The depositional sequence 1–2 unconformity, which falls in the sub-trilobitic Lower Cambrian Watsonella crosbyi Zone of the Chapel Island Formation, persists for 650 km along the marginal platform from southeastern Newfoundland to southern New Brunswick and, potentially, appears in Cape Breton Island. Latest Precambrian-earliest Cambrian epeirogenic and depositional history was very uniform along the marginal platform, and a unified lithostratigraphic nomenclature is appropriate.  相似文献   

Crustal observations beneath the southern North Sea and their tectonic and geological implications     

Richard H.B. Rijkers  Ed J.Th. Duin 《Tectonophysics》1994,240(1-4):215-224

In 1991, a deep seismic reflection line, MPNI-9101, was acquired in the southern North Sea from the Mesozoic Broad Fourteens Basin, across the West Netherlands Basin onto the London-Brabant Massif (LBM). The resultant section shows a strongly reflective lower crust beneath the area of Mesozoic basin development. This lower crustal reflectivity continues to be strong beneath the LBM. The travel time to the base of the reflective zone increases from approximately 11.0 s beneath the Mesozoic basins to 12.5 s beneath the LBM, suggesting a southward thickening of the crust (Rijkers et al., 1993). Based on these travel times and information from deep wells and refraction surveys. Moho depth is estimated to increase from about 31 km beneath the Mesozoic basins to about 38 km beneath the LBM. This difference in depth to the Moho can partly be explained by coaxial stretching of the crust beneath the Mesozoic basins. In comparison with the Mesozoic basins, the crust beneath the LBM was thickened during the Caledonian and Variscan orogenies.  相似文献   

Telecommunications Synchronization and GPS   总被引：1，自引：0，他引：1  

Ed Butterline  Sally L. Frodge 《GPS Solutions》2001,5(1):51-54

Today, the Global Positioning System (GPS) is the technology most frequently selected for use in digital communication networks to meet the requirement for precision timing synchronization. The technological evolution of the telecommunications industry over the past 30 years has driven this constantly growing demand for higher performance and timing accuracy. Increased timing accuracy provides overall improvements in system performance, quality, and efficiency. In the United States and in many parts of the world, the telecommunications infrastructure uses the GPS signal as an integral and basic part of the system. The stability of GPS, ongoing health of the GPS constellation, and GPS signal quality can mpact telecommunications systems. ? 2001 John Wiley & Sons, Inc.  相似文献   

R. E. (Ted) Munn — Founding editor; a mini-biography     

Peter Taylor  Morley Thomas  Ed Truhlar  Doug Whelpdale 《Boundary-Layer Meteorology》1996,78(1-2):3-8

Ted Munn founded Boundary-Layer Meteorology in 1970 and served as Editor for 75 volumes over a 25 year period. This short article briefly reviews Ted's scientific career with the Atmospheric Environment Service (of Canada), the International Institute for Applied Systems Analysis in Austria and with the Institute of Environmental Studies at the University of Toronto, and as editor of this journal.  相似文献   

A numerical integration of a two-level quasi-geostrophic model with variable Rossby parameter     

Dr. A. Huss 《Meteorology and Atmospheric Physics》1967,16(2-3):105-125

Summary Circulation patterns were obtained from a two-level quasi-geostrophic model, in which the Rossby parameter varied with latitude. The initial basic state was characterized by a constant zonal flow at both reference level. The results we re compared with the pattern obtained in a series of experiments with a similar model, in which the Rossby parameter was assumed to be constant. the initial zonal flow in these experiments was assumed in one case to be constant with latitude, in the second casse to have a symmetrical jet centered on the central latitude, and in the thrid case to have its maximum in the southern half of the region. the results of the experiment with a variable Rossby parameter have the closest resemblance to the patterns observed in the real atmospehre. In particular, during the mature stages of the run, the distribution of the zonallyaveraged eddytransport of momentum corresponded quite well to patterns actually observed in the atmosphere.

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Zusammenfassung Aus einem quasi-geostrophischen Modell mit breitenabhängigem rossby-Parameter wurden Zirkulationsformen errechnet. Der Anfangszustand war durc eine konstante zonale Strömung in zwei Niveaus charakteriseirt. Die Resultate wurden mit Zirkulationen verglichen, die in einer Reihe von Experimenten mit einem ähnlichen Modell, in dem aber der Rossby-Parameter konstant angenommen war, erhalten worden waren. In einemk dieser Fälle wurde angenommen, daß die ursprüngliche zonale Strömung breitenunabhängig war, in einem anderen fall wurde angenommen, daß die Strömung in einem symmetrischen Jetstream über eine mittleren Breite konzentriert war, und in einem dritten Fall wurden angenommen, daß die zonale Strömung ihr Maximum in der südlichen Hälfte des Bereiches hatte. Die Resultate des Experiments mit dem veränderlichen Rossby-Parameter haben die meiste Ähnlichkeit mit Zirkulationsformen in der wirklichen Atmosphäre. Insbesondere paßt die Verteilung des zonal gemittelten Momentumtransports in den Reifestadien des Versuchs gut zu den tatsächlich in der Atmosphäre beobachteten Zirkulationsformen.

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Résumé On a calculé les formes de circulation découlant d'un modèle quasigéostrophique dont le paramètres de Rossby dépendaient de la latitude. L'état initial en était caractérisé par un courant zonal constant aux deux niveaux. Lels résultats ont été comparés à ceux d'une série d'essais effectués avec un modèle semblable, mais dans lequel les paramètres de Rossby restaient constants. Dans un de ces cas, on a admis que la circulation zonale initiale ne dépendait pas de la latitude. Dans un deuxième, on a simulé un jet symétriquement à une latitude moyenne. Dans un troisième enfin, on a placè le maximum de la circulation zonale dans la moitié sud de l'espace étudié. Les résultats obtenus en partant des essais basés sur un paramètre de Rossby variable sont les plus semblables aux formes de circulation observées réellement dans l'atmosphère. En particulier, la répartition du transport turbulent de la quantité de mouvement — moyenne zonale calculée au stade de maturité de l'essai — est très voisine des formes de circulation observées réellement dans l'atmosphère.

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With 9 Figures

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The research reported in this document has been sponsored by the Air Force Cambridge Research Laboratories under Grant AF EOAR 63-108 through the European Office of Aerospace Reasearch (OAR), United States Air Force.  相似文献