Detailed S-wave structure in the Dublin Basin and its northern margin     

N. P. Murphy  A. W. B. Jacob 《Geophysical Journal International》1985,83(3):803-807

Summary. The seismic structure has been measured to a depth of about 3 km along a 30 km seismic profile in east central Ireland. This profile is unusual in that it is the S -wave velocity—depth structure that has been measured to a degree of precision more normally associated with P -wave results. One reason for this is that the sources used were quarry blasts which generated strong S -waves and short-period surface waves but rather weak P -waves.
The results show a layer of Carboniferous limestone with shear velocity 2.65 km⁻¹ s overlying a layer with a velocity of 3.06 km s⁻¹. This second layer was interpreted as Lower Palaeozoic strata (Silurian/Ordovician) since this velocity was evident in an inlier seen at the surface at the northern end of the line. A third refraction horizon, shear velocity 3.45 km s⁻¹ and displaying a basinal structure, was also recognized. This may be Cambrian or Precambrian basement.  相似文献   

Resilient characterization of pavement materials     

Jacob Uzan 《国际地质力学数值与分析法杂志》1992,16(6):453-459

The paper presents an approach for characterizing pavement materials using the modified linear elastic behaviour. The secant modulus of elasticity is expressed in terms of the stress invariants and an expression for the secant Poisson's ratio is derived using path independence of the total work along a closed loading cycle. Triaxial test results of granular base–subbase materials which exhibit strong non-linear behaviour and dilatancy are analysed and presented. The constitutive law is included in a finite element program and results of pavement analyses are discussed. It is found that the secant Poisson's ratio of granular base materials reaches values between 0·6 and 0·7, indicating a volume increase under high stress ratios. The pavement response predicted using the above material characterization is compatible with non-destructive test results.  相似文献   

Biogeographical drivers of ragweed pollen concentrations in Europe     

Matyasovszky  István  Makra  László  Tusnády  Gábor  Csépe  Zoltán  Nyúl  László G.  Chapman  Daniel S.  Sümeghy  Zoltán  Szűcs  Gábor  Páldy  Anna  Magyar  Donát  Mányoki  Gergely  Erostyák  János  Bodnár  Károly  Bergmann  Karl-Christian  Deák  Áron József  Thibaudon  Michel  Albertini  Roberto  Bonini  Maira  Šikoparija  Branko  Radišić  Predrag  Gehrig  Regula  Rybníček  Ondřej  Severova  Elena  Rodinkova  Victoria  Prikhodko  Alexander  Maleeva  Anna  Stjepanović  Barbara  Ianovici  Nicoleta  Berger  Uwe  Seliger  Andreja Kofol  Weryszko-Chmielewska  Elżbieta  Šaulienė  Ingrida  Shalaboda  Valentina  Yankova  Raina  Peternel  Renata  Ščevková  Jana  Bullock  James M. 《Theoretical and Applied Climatology》2018,133(1-2):277-295

Theoretical and Applied Climatology - The drivers of spatial variation in ragweed pollen concentrations, contributing to severe allergic rhinitis and asthma, are poorly quantified. We analysed the...  相似文献   

Nanostructure, composition and mechanisms of bivalve shell growth   总被引：3，自引：0，他引：3  

D.E. Jacob  A.L. Soldati  J. Huth  W. Hofmeister 《Geochimica et cosmochimica acta》2008,72(22):5401-5415

Freshwater and marine cultured pearls form via identical processes to the shells of bivalves and can therefore serve as models for the biomineralization of bivalve shells in general. Their nanostructure consists of membrane-coated granules (vesicles) which contain amorphous calcium carbonate (ACC) at the beginning of the biomineralization sequence, preceding the crystallization of aragonite and vaterite. In contrast to the commonly accepted view, crystallization of ACC occurs rapidly and within the granular nano-compartments mediated by organic molecules much earlier than platelet formation. The interlamellar organic sheets in nacre that form the platelet structure of nacre themselves form by self-organization after the crystallization process of CaCO₃ is completed and, thus, cannot serve as a nucleation template for aragonite. Pores in the organic sheets are postulated to be a result of this process rather than to represent the pathways for CaCO₃ through pre-existing interlamellar sheets. The amorphous phase has the highest concentrations of Mg (5.8 mol%), Mn (6.6 mol%), S (4.7 mol%) and P (1 mol%) of the three CaCO₃-polymorphs. Mg/Ca and Mn/Ca ratios are found to decrease in the order ACC > vaterite > aragonite, corresponding to decreasing organic content in the different phases. This, as well as an observed enrichment of Mg in the organic-rich growth-banding of the pearls, suggests an at least partially organic speciation of Mg and Mn in bivalves and may be responsible for the observed physiological influence on Mg/Ca and Mn/Ca ratios in bivalves as a proxy for environmental parameters.  相似文献   

Alonso's Theory of Movements: Developments in Spatial Interaction Modeling   总被引：1，自引：1，他引：1  

Jacob J. de Vries  Peter Nijkamp  Piet Rietveld 《Journal of Geographical Systems》2001,3(3):233-256

 The Spatial Interaction Model proposed by Alonso as “Theory of Movements” offers an innovative specification of spatial origin-destination flow models. Equations for flows between regions, total outflow from and total inflow to a region are linked by balancing factors. This paper presents a consistent formulation of Spatial Interaction Models in the Wilson tradition and Alonso's Theory of Movements. The paper is intended as an introduction to the model and a review of␣the state of the art. Besides it is argued that simultaneous equation techniques are required to estimate the so-called systemic parameters. Received: 21 May 2000 / Accepted: 18 January 2001  相似文献   

Zooplankton distribution and abundance in saline lakes of British Columbia,Canada   总被引：2，自引：0，他引：2  

U. Theodore Hammer  László Forró 《International Journal of Salt Lake Research》1992,1(1):65-80

Zooplankton in saline lakes of the Southern Interior Plateau of British Columbia were collected on three occasions: mid-May and early August, 1990, and in late July, 1991. Salinities ranged from 2.6 to 45.8 g L⁻¹. Of the 17 lakes examined, 13 were hyposaline (∼-20g L⁻¹), four, mesosaline (20–50 g L⁻¹) and none, hypersaline (>50 g L⁻¹). pH ranged from 8.7 (Three Mile) to 10.7 (Goodenough), with values <9.6 in 10, and <9.0 in only three lakes. Lakes with high pHs had high bicarbonate-carbonate alkalinities. Thirty one species of zooplankton occurred: Protista (1), Rotifera (13), Anostraca (2), Cladocera (7), Ostracoda (1) and Copepoda (7). Sixteen species were restricted to hyposaline waters, with seven found only in salinities of ≤5 gL⁻¹. Two species (Diaptomus connexus, Artemia franciscana) were restricted to mesosaline waters of salinity >35 g L⁻¹. Eurysaline species includedBrachionus plicatilis, Hexarthra fennica, Limnocythere staplini, Artemia franciscana andDiaptomus connexus. Most species were abundant in 1+ lakes, but six species always had low populations.B. plicatilis, Hexarthra polyodonta, A. franciscana, Limnocythere staplini, Daphnia similis andD. connexus had densest populations in one or more of the three most saline lakes, viz. Long, Goodenough and Three Mile. Cladocerans other thanD. similis (Alona sp., Ceriodaphnia quadrangula, Daphnia pulex) were usually abundant in lakes of low salinity (<5 g L⁻¹).Diatomus sicilis, present in all except the three most saline lakes, also occurred in abundance in ten of these lakes.Moina hutchinsoni andH. polyodonta were present in both hyposaline and mesosaline lakes, but, more importantly, tended to occur only at higher pH values (>pH 9.4) but not in all such lakes. These can be regarded as alkaline-saline species. Sorensen’s Coefficient of Community Similarity was used to compare communities in Alberta-Saskatchewan and British Columbia. It was low (0.37). A comparison restricted to just Cladocera gave a slightly higher value, 0.44, but a comparison of Copepoda gave a value of 71 per cent similarity between the regions. Multiple regression analyses using pH, TDS and K regressed on species richness for all samples accounted for only 41 per cent of the variance. However, when the analysis was seasonally restricted (May), and thus to a limited chemical range, 47 to 77.5 per cent of the variance was accounted for by these three variables.  相似文献   

Treatment of rotation errors in the final adjustment of GPS baseline components     

László Bányai 《Journal of Geodesy》1991,65(2):102-108

Summary The significant coordinate difference changes of the same baselines, measured in different observing sessions, may be interpreted as the rotation around the station held fixed during the differenced processing, if the length changes of these baselines show random behavior. These rotation errors can significantly bias the final network adjustment based on redundant observing sessions and a relative approach. The Gauss-Helmert model with the estimation of the stochastic properties of the rotation errors is the most effective investigated approach. The standard deviation of the baseline length differences between those derived from a precise geodetic network and derived by Trimvec relative positioning software improved by a factor 2.4 after the final network adjustment using the introduced Gauss-Helmert model.  相似文献   

Computer estimation of intensities: The 1985 Berhida,Hungary, earthquake     

Tibor Zsíros  Péter Mónus  László Tóth 《Pure and Applied Geophysics》1990,132(3):533-543

In this paper a computerized method for the intensity estimation from macroseismic observations is presented. The successive steps of the MSK intensity scale (2° to 10°) receives weights according to the observations marked on the earthquake questionnaires. These weights are summed for the individual scale steps. The distribution of these summed weights and their relation to an experimentally chosen function of the criterion make it possible to estimate the appropriate intensity value and its reliability. By computer evaluation of earthquake reports an objective comparison of estimated intensities given by different seismologists can be made, provided that uniform earthquake questionnaires are used. The application of this method will result in more homogeneous intensity data.  相似文献   

Well-Purging Criteria for Sampling Purgeable Organic Compounds     

Jacob Gibs  Thomas E. Lmbrigiotta 《Ground water》1990,28(1):68-78

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Determination of total carbonate content in some representative loess-paleosol profiles     

László Gerei  János Balogh  Magda Reményi 《GeoJournal》1995,36(2-3):187-188

Samples taken from loess and paleosols were examined for carbonate content. The main results were as follows:

1. The carbonate content measured differed significantly when the samples were analysed jointly with the concretions occurring in them or separately from these constituents.
2. Solubility of different carbonates (calcite, dolomite, aragonite etc.) was found different. This factor also might have influenced the measured total amounts of carbonates.

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