Measuring and modelling the redshift evolution of clustering: the Hubble Deep Field North     

S. Arnouts  S. Cristiani  L. Moscardini  S. Matarrese  F. Lucchin  A. Fontana  E. Giallongo 《Monthly notices of the Royal Astronomical Society》1999,310(2):540-556

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The Influence of Streambed Heterogeneity on Hyporheic Flow in Gravelly Rivers     

YaoQuan Zhou  Robert W. Ritzi Jr.  Mohamad Reza Soltanian  David F. Dominic 《Ground water》2014,52(2):206-216

Deposits of open‐framework gravel occurring in gravelly streambeds can exert a significant influence on hyporheic flow. The influence was quantified using a numerical model of the hyporheic zone. The model included open‐framework gravel stratasets represented with commonly observed characteristics including a volume fraction of about one‐third of the streambed sediment, a hydraulic conductivity two orders of magnitude greater than other strata present, and a spatial connectivity forming preferential‐flow pathways. The influence of open‐framework gravel stratasets on hyporheic flow was much greater than the influence of the channel morphology including meanders, point bars, dunes, and ripples. Seventy percent of the total hyporheic exchange occurred across 30% of the channel boundary at locations of open‐framework gravel stratasets. The maximum local interfacial flux rates occurred at these locations, and were orders of magnitude greater than those at other locations. The local flux rates varied by six orders of magnitude over the channel boundary. The composite flow rate through the model with open‐framework gravel stratsets was an order of magnitude greater than that through an equivalent but homogeneous model.  相似文献   

Geochemistry and potential use of groundwater in the Rocca Busambra area (Sicily, Italy)     

M. Fontana  F. Grassa  G. Cusimano  R. Favara  S. Hauser  C. Scaletta 《Environmental Geology》2009,57(4):885-898

In the Rocca Busambra area (mid-west Sicily, Italy), from November 1999 to July 2002, 23 water points including wells and springs were sampled and studied for their chemical and isotopic compositions. Two rain gauges were also installed at different altitudes, and rainwater was collected monthly to determine the isotopic composition. The obtained results revealed the Rocca Busambra carbonate complex as being the main recharge area on account of its high permeability value. From a chemical view point, two main groups of water can be distinguished: calcium–magnesium–bicarbonate-type and calcium–magnesium–chloride–sulphate-type waters. The first group reflects the dissolution of the carbonate rocks; the second group probably originates from circulation within flyschoid sediments. Three water wells differ from the other samples due to their relatively high Na and K content, which probably is to be referred to a marked interaction with the “Calcareniti di Corleone” formation, which is rich in glauconite [(K, Na)(Fe³⁺, Al, Mg)₂(Si, Al)₄O₁₀(OH)₂]. In accordance with WHO guidelines for drinking water (2004), almost all the samples collected can be considered drinkable, with the exception of four of them, whose NO₃ ⁻, F⁻ and Na⁺ contents exceed the limits. On the contrary, the sampled groundwater studied is basically suitable for irrigation.  相似文献   

Geomicrobiology of cores from Suruí Mangrove - Guanabara Bay - Brazil     

Luiz Francisco Fontana  João Graciano Mendonça Filho 《Marine pollution bulletin》2010,60(10):1674-1681

The aim of this work was to quantify the biopolymers associated to esterase enzymes and identify bacterial respiratory activity in four cores collected in Suruí Mangrove, Guanabara Bay - RJ. Biopolymer concentration was 1000 times lower than previously reported in the literature, indicating the need for creating and establishing eutrophication indicative rates and records compatible with tropical coastal systems. The biochemical representative relationships in the cores were equivalent to those from studies on coastal marine environments made in the Northern Hemisphere. The esterase enzymes in the sediment proved efficient in the mineralization of biopolymers, even with preferentially anaerobic metabolic physiology. Despite the lack of incipient geomicrobiological studies, the results highlighted the possible application of microbiology to a better understanding of geological processes.  相似文献   

Component correlations in structure‐specific seismic loss estimation     

Brendon A. Bradley  Dominic S. Lee 《地震工程与结构动力学》2010,39(3):237-258

This paper addresses correlations between multiple components in structure‐specific seismic loss estimation. To date, the consideration of such correlations has been limited by methodological tractability, increased computational demand, and a paucity of data for their computation. The effect of component correlations, which arises in various forms, is however a significant factor affecting the results of structure‐specific seismic loss estimation and therefore it is prudent that adequate consideration be given to their effect. This paper provides the details of a tractable and computationally efficient seismic loss estimation methodology in which correlations can be considered. Methods to determine the necessary correlations are discussed, particularly those that can be used in the absence of sufficient empirical data, for which values are suggested based on the judgement. The effects of various assumptions regarding correlations are illustrated via application to a case‐study office structure. It is observed that certain correlation assumptions can lead to errors in excess of 50% in the lognormal standard deviation in the loss given intensity and loss hazard relationships, while full consideration of partial correlations is 50 times more computationally expensive than other assumptions. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   

Simulating soil stiffness degradation in transient site response predictions     

Wei Li  Dominic Assimaki 《Soil Dynamics and Earthquake Engineering》2010,30(5):299-309

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A Place to Howl: A GIS Instructional Module on the Mexican Gray Wolf     

Paul R. Baumann  Dominic Oppedisano 《国际地球制图》2013,28(4):73-79

Abstract

This paper covers the development of a GIS instructional module centered on the reintroduction of the Mexican Gray Wolf in the Southwest, United States. This module is used in an undergraduate geography course on the United States. The paper also reports on how forty‐one students applied the module in trying to find an appropriate location to reintroduce the wolf.  相似文献   

Cation substitution in synthetic meridianiite (MgSO<Subscript>4</Subscript>·11H<Subscript>2</Subscript>O) I: X-ray powder diffraction analysis of quenched polycrystalline aggregates     

A.?Dominic?FortesEmail author  Frank?Browning  Ian?G.?Wood 《Physics and Chemistry of Minerals》2012,39(5):419-441

Meridianiite, MgSO₄·11H₂O, is the most highly hydrated phase in the binary MgSO₄–H₂O system. Lower hydrates in the MgSO₄–H₂O system have end-member analogues containing alternative divalent metal cations (Ni²⁺, Zn²⁺, Mn²⁺, Cu²⁺, Fe²⁺, and Co²⁺) and exhibit extensive solid solution with MgSO₄ and with one another, but no other undecahydrate is known. We have prepared aqueous MgSO₄ solutions doped with these other cations in proportions up to and including the pure end-members. These liquids have been solidified into fine-grained polycrystalline blocks of metal sulfate hydrate + ice by rapid quenching in liquid nitrogen. The solid products have been characterised by X-ray powder diffraction, and the onset of partial melting has been quantified using a thermal probe. We have established that of the seven end-member metal sulfates studied, only MgSO₄ forms an undecahydrate; ZnSO₄ forms an orthorhombic heptahydrate (synthetic goslarite), MnSO₄, FeSO₄, and CoSO₄ form monoclinic heptahydrates (syn. mallardite, melanterite, bieberite, respectively), and CuSO₄ crystallises as the well-known triclinic pentahydrate (syn. chalcanthite). NiSO₄ forms a new hydrate which has been indexed with a triclinic unit cell of dimensions a = 6.1275(1) Å, b = 6.8628(1) Å, c = 12.6318(2) Å, α = 92.904(2)°, β = 97.678(2)°, and γ = 96.618(2)°. The unit-cell volume of this crystal, V = 521.74(1) ų, is consistent with it being an octahydrate, NiSO₄·8H₂O. Further analysis of doped specimens has shown that synthetic meridianiite is able to accommodate significant quantities of foreign cations in its structure; of the order 50 mol. % Co²⁺ or Mn²⁺, 20–30 mol. % Ni²⁺ or Zn²⁺, but less than 10 mol. % of Cu²⁺ or Fe²⁺. In three of the systems we examined, an ‘intermediate’ phase occurred that differed in hydration state both from the Mg-bearing meridianiite end-member and the pure dopant end-member hydrate. In the case of CuSO₄, we observed a melanterite-structured heptahydrate at Cu/(Cu + Mg) = 0.5, which we identify as synthetic alpersite [(Mg_0.5Cu_0.5)SO₄·7H₂O)]. In the NiSO₄- and ZnSO₄-doped systems we characterised an entirely new hydrate which could also be identified to a lesser degree in the CuSO₄- and the FeSO₄-doped systems. The Ni-doped substance has been indexed with a monoclinic unit-cell of dimensions a = 6.7488(2) Å, b = 11.9613(4) Å, c = 14.6321(5) Å, and β = 95.047(3)°, systematic absences being indicative of space-group P2₁/c with Z = 4. The unit-cell volume, V = 1,176.59(5) ų, is consistent with it being an enneahydrate [i.e. (Mg_0.5Ni_0.5)SO₄·9H₂O)]. Similarly, the new Zn-bearing enneahydrate has refined unit cell dimensions of a = 6.7555(3) Å, b = 11.9834(5) Å, c = 14.6666(8) Å, β = 95.020(4)°, V = 1,182.77(7) ų, and the new Fe-bearing enneahydrate has refined unit cell dimensions of a = 6.7726(3) Å, b = 12.0077(3) Å, c = 14.6920(5) Å, β = 95.037(3)°, and V = 1,190.20(6) ų. The observation that synthetic meridianiite can form in the presence of, and accommodate significant quantities of other ions increases the likelihood that this mineral will occur naturally on Mars—and elsewhere in the outer solar system—in metalliferous brines.  相似文献   

Future wave climate over the west-European shelf seas     

Anna Zacharioudaki  Shunqi Pan  Dave Simmonds  Vanesa Magar  Dominic E. Reeve 《Ocean Dynamics》2011,61(6):807-827

In this paper, we investigate changes in the wave climate of the west-European shelf seas under global warming scenarios. In particular, climate change wind fields corresponding to the present (control) time-slice 1961–2000 and the future (scenario) time-slice 2061–2100 are used to drive a wave generation model to produce equivalent control and scenario wave climate. Yearly and seasonal statistics of the scenario wave climates are compared individually to the corresponding control wave climate to identify relative changes of statistical significance between present and future extreme and prevailing wave heights. Using global, regional and linked global–regional wind forcing over a set of nested computational domains, this paper further demonstrates the sensitivity of the results to the resolution and coverage of the forcing. It suggests that the use of combined forcing from linked global and regional climate models of typical resolution and coverage is a good option for the investigation of relative wave changes in the region of interest of this study. Coarse resolution global forcing alone leads to very similar results over regions that are highly exposed to the Atlantic Ocean. In contrast, fine resolution regional forcing alone is shown to be insufficient for exploring wave climate changes over the western European waters because of its limited coverage. Results obtained with the combined global–regional wind forcing showed some consistency between scenarios. In general, it was shown that mean and extreme wave heights will increase in the future only in winter and only in the southwest of UK and west of France, north of about 44–45° N. Otherwise, wave heights are projected to decrease, especially in summer. Nevertheless, this decrease is dominated by local wind waves whilst swell is found to increase. Only in spring do both swell and local wind waves decrease in average height.  相似文献   

“This is the mess that we are living in”: residents everyday life experiences of living in a stigmatized community     

Dominic?Odwa?AtariEmail author  Isaac?Luginaah  Jamie?Baxter 《GeoJournal》2011,76(5):483-500

This paper is part of a larger community health study aimed at delineating the determinants of health in Sarnia. The paper specifically investigates Sarnia residents’ daily lived experiences, perceptions of and responses to living within the St. Clair River “Area of Concern” (AOC) as designated by the federal government based on the hypothesis that relatively high levels of environmental pollution in the region are negatively influencing human health. Results from in-depth interviews (N = 27) show that residents of Sarnia are conflicted by the elevation of awareness about environmental health threats by being labelled within an AOC. Residents use their emotional and sensual experiences to adopt appropriate coping strategies to live within a contaminated community. In contextualizing their everyday lived realities, residents argued that living in an AOC demands personal acceptance of the conditions in Sarnia and awareness of “bad air days” to cope with pollution exposure. Yet, residents were not willing to abandon Sarnia because of their cultural, social, and economical attachments to the place they call home. These findings suggest the need for local health policies that incorporate local concerns and perceptions of how environmental pollution affects people’s experiences and well-being. There is a necessity to involve community members as central participants in the process of policy making.  相似文献