The recognition of multiple magmatic events and pre-existing deformation zones in metamorphic rocks as illustrated by CL signatures and numerical modelling: examples from the Ballachulish contact aureole, Scotland     

Helena Bergman  Sandra Piazolo 《International Journal of Earth Sciences》2012,101(5):1127-1148

The combination of cathodoluminescence (CL) analysis, temperature and temperature–time calculations, and microstructural numerical modelling offers the possibility to derive the time-resolved evolution of a metamorphic rock. This combination of techniques is applied to a natural laboratory, namely the Ballachulish contact aureole, Scotland. Analysis of the Appin Quartzite reveals that the aureole was produced by two distinct magmatic events and infiltrated by associated fluids. Developing microstructures allow us to divide the aureole into three distinct regions. Region A (0–400?m, 663°C?<?T _max?<?714°C) exhibits a three-stage grain boundary migration (GBM) evolution associated with heating, fluid I and fluid II. GBM in region B (400–700?m, 630°C?<?T _max?<?663°C) is associated with fluid II only. Region C (>700?m of contact, T _max?<?630°C) is characterised by healed intragranular cracks. The combination of CL signature analysis and numerical modelling enables us to recognise whether grain size increase occurred mainly by surface energy-driven grain growth (GG) or strain-induced grain boundary migration (SIGBM). GG and SIGBM result in either straight bands strongly associated with present-day boundaries or highly curved irregular bands that often fill entire grains, respectively. At a temperature of ~620°C, evidence for GBM is observed in the initially dry, largely undeformed quartzite samples. At this temperature, evidence for GG is sparse, whereas at ~663°C, CL signatures typical for GG are commonplace. The grain boundary network approached energy equilibrium in samples that were at least 5?ka above 620°C.  相似文献   

THE MULTINATIONAL CORPORATION     

Edward F. Bergman 《The Professional geographer》1973,25(3):255-260

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ComparativeP-postlabeling analysis of DNA Adducts in Perch (Perca fluviatilis) from unpolluted and polluted areas in Swedish coastal waters     

Gunilla Ericson  Birgitta Liewenborg  Lennart Balk 《Marine environmental research》1995,39(1-4)

Perch (Perca fluviatilis), were sampled from unpolluted and polluted areas in Swedish coastal waters. The level of aromatic/hydrophobic DNA adducts in liver tissue was analyzed using the nucleas P1 version of the³²P-post-labeling assay. The level of total adducts measured in the individual fish from polluted areas was between 6 and 22 nmol of adducts/mol of nucleotides, and in the fish from the reference area between 0.2 and 0.6 nmol of adducts/mol of nucleotides.  相似文献   

Using global genome approaches to address problems in cod mariculture     

Goetz  Frederick W.; McCauley  Linda; Goetz  Giles W.; Norberg  Birgitta 《ICES Journal of Marine Science》2006,63(2):393-399

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Spatial and temporal trends of EROD-activity in plaice (Pleuronectes platessa) and flounder (Platichthys flesus)     

Martin Eggens  Andr Bergman 《Marine environmental research》1995,39(1-4)

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The border as an engine for mobility and spatial integration: A study of commuting in a Swedish–Norwegian context     

Cecilia Möller  Eva Alfredsson-Olsson  Birgitta Ericsson  Kjell Overvåg 《Norsk geografisk tidsskrift. Norwegian journal of geography》2018,72(4):217-233

The purpose of the study was to analyse how cross-border commuting differed from intranational commuting in Sweden, and how cross-border mobilities affected spatial integration. The authors analysed patterns and spatial flows of cross-border commuting by comparing them with characteristics of intranational commuting. In the article, they explore the assumption that the border constitutes an ‘engine’ for work-related mobility, which affects processes of spatial integration in cross-border areas. The empirical material comprised data from surveys of commuting from the Swedish county of Värmland to Norway and commuting within Värmland. The findings showed that cross-border commuting shared common features with intranational commuting, including how the frequency of commuting was dependent on distance. The motives for commuting differed, and the reasons for working in Norway were economic rather than professional. In terms of spatial integration, cross-border commuting was mainly one-directional, from Sweden to Norway, while leisure mobility and migration tended to be in the opposite direction. The authors conclude that the border region is characterised by integration through specialisation, which involves a permanent state of ‘transient’ mobility. Thus, a win-win situation can be distinguished, in which the border serves as a resource and an ‘engine’ for cross-border integration, mobility and economic activities.  相似文献   

Magnetic Rossby waves in a stably stratified layer near the surface of the Earth's outer core     

Michael I. Bergman 《地球物理与天体物理流体动力学》2013,107(1-4):151-176

Abstract

The stratification profile of the Earth's magnetofluid outer core is unknown, but there have been suggestions that its upper part may be stably stratified. Braginsky (1984) suggested that the magnetic analog of Rossby (planetary) waves in this stable layer (the ‘H’ layer) may be responsible for a portion of the short-period secular variation. In this study, we adopt a thin shell model to examine the dynamics of the H layer. The stable stratification justifies the thin-layer approximations, which greatly simplify the analysis. The governing equations are then the Laplace's tidal equations modified by the Lorentz force terms, and the magnetic induction equation. We linearize the Lorentz force in the Laplace's tidal equations and the advection term in the magnetic induction equation, assuming a zeroth order dipole field as representative of the magnetic field near the insulating core-mantle boundary. An analytical β-plane solution shows that a magnetic field can release the equatorial trapping that non-magnetic Rossby waves exhibit. A numerical solution to the full spherical equations confirms that a sufficiently strong magnetic field can break the equatorial waveguide. Both solutions are highly dissipative, which is a consequence of our necessary neglect of the induction term in comparison with the advection and diffusion terms in the magnetic induction equation in the thin-layer limit. However, were one to relax the thin-layer approximations and allow a radial dependence of the solutions, one would find magnetic Rossby waves less damped (through the inclusion of the induction term). For the magnetic field strength appropriate for the H layer, the real parts of the eigenfrequencies do not change appreciably from their non-magnetic values. We estimate a phase velocity of the lowest modes that is rather rapid compared with the core fluid speed typically presumed from the secular variation.  相似文献   

Dioxins and PCBs in Greenland shark (Somniosus microcephalus) from the North-East Atlantic     

Strid A  Jörundsdóttir H  Päpke O  Svavarsson J  Bergman A 《Marine pollution bulletin》2007,54(9):1514-1522

The Greenland shark (Somniosus microcephalus) is a high-trophic fish species present in Arctic waters. The present study aimed to determine concentrations of polychlorinated dibenzo-p-dioxins and furans (PCDDs/Fs), dioxin-like (DL) PCBs and six non-dioxin-like (NDL) PCBs in muscle and liver from 10 female Greenland sharks collected between 2001 and 2003 from Icelandic waters. The mean total concentrations of PCDDs/Fs were 13 and 530pg/g fat for muscle and liver, respectively, and show enrichment in the liver. Concentrations of DL-non-ortho PCBs were also higher in liver compared to muscle with mean concentrations of 7.8 and 0.36ng/g fat, respectively. No enrichment in the liver was found for DL-mono-ortho- and NDL-PCBs. No correlation was found between the size range studied and total concentrations of the compounds analyzed. Total WHO-TEQs (PCDDs/Fs and DL-PCBs) ranged between 7.1-70 and 54-1500pg/g fat in muscle and liver, respectively.  相似文献   

On the moments of time to first passage of the linear oscillator     

L. A. Bergman  J. C. Heinrich 《地震工程与结构动力学》1981,9(3):197-204

The moments of time to first passage of the response process of the linear oscillator excited by a stationary wide-band process are obtained numerically for the symmetric two-sided barrier problem. A recursive set of partial differential equations governing the moments is solved using a Petrov-Galerkin finite element method. Stable, accurate solutions for the first few moments are calculated over a wide range of oscillator damping.  相似文献   

The 1994 Sefidabeh (eastern Iran) earthquakes revisited: new evidence from satellite radar interferometry and carbonate dating about the growth of an active fold above a blind thrust fault   总被引：2，自引：0，他引：2  

B. Parsons  T. Wright  P. Rowe  J. Andrews  J. Jackson  R. Walker  M. Khatib  M. Talebian  E. Bergman  E. R. Engdahl 《Geophysical Journal International》2006,164(1):202-217

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