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141.
Fixed wavelength fluorescence (FF) of bile was used as a biomarker for PAH exposure in fish caged adjacent to an aluminium works. After 30 days of caging, a 20–50 fold increase of pyrene fluorescence was found in groups caged adjacent to the works as compared to two control groups. The PAH uptake occurred mainly from suspended particles rather than from PAH contaminated sediments at the caging sites. Our results demonstrates the combined use of fish caging and bile-fluorescence measurements as a powerful field model for the monitoring of coastal waters subjected to PAH pollution. 相似文献
142.
Filip Nilenius Fredrik Larsson Karin Lundgren Kenneth Runesson 《国际地质力学数值与分析法杂志》2013,37(11):1535-1551
Effective moisture and chloride ion diffusivity coefficients for concrete are determined by computational homogenization, where concrete is modeled on the mesoscale as a heterogenous three‐phase composite material. By imposing moisture and chloride ion gradients on a representative volume element, effective macroscale properties are obtained through finite element analysis. A parametric study of the effects of the ballast content was carried out. The numerical results correspond well with an estimate of the Hashin–Shtrikman type available in the literature. The computational homogenization strategy proposed here also includes the interfacial transition zone, and its influence on the effective diffusivity coefficients is assessed. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
143.
Quantitative methods for estimating flood fatalities: towards the introduction of loss-of-life estimation in the assessment of flood risk 总被引:1,自引:0,他引:1
Risk, including flood risk, can be defined as ??the combination of the probability of an event and its consequences??. Assessing and managing the risk from flooding should explicitly include the estimation of impacts to people. Extensive research is currently ongoing looking at both quantitative and qualitative approaches for assessing flood impacts on people. Although there is some literature available on such approaches, examples of methodological and routinely applications of these methodologies as part of flood risk assessments are rare. This paper focuses on quantitative approaches for estimating impacts of flooding to people, notably on methods for assessing fatality numbers associated with flooding. Three methods for assessing losses of life are discussed in detail. The methods discussed here constitute the forefront of research in Canada, UK and The Netherlands. These methods provide an assessment of the physical consequences of flooding on people and can be used to introduce the impacts to people as quantitative metric for the assessment of flood risk. In this paper, the three methodologies are discussed and applied in a UK case study reproducing the 1953 East Coast flood event. This study aims to provide a comprehensive comparison on both the reliability and the applicability of the methods. We analyse possible added values on using of these methods in systematic analyses, aiming to provide guidelines for applying these methods for flood fatality risk assessment. 相似文献
144.
23 October 2011 Van (Turkey) earthquake 总被引:2,自引:0,他引:2
An earthquake of Mw7.2 on 23 October 2011 occurred in the Van region of Eastern Turkey. The main shock and long series aftershocks caused significant damage and claimed 644 lives. The particular features and the lessons learned are covered. 相似文献
145.
Ilham Bouimetarhan Lydie Dupont Enno Schefuß Gesine Mollenhauer Stefan Mulitza Karin Zonneveld 《Quaternary Research》2009,72(2):188-197
Pollen and organic-walled dinoflagellate cyst assemblages from core GeoB 9503-5 retrieved from the mud-belt ( 50 m water depth) off the Senegal River mouth have been analyzed to reconstruct short-term palaeoceanographic and palaeoenvironmental changes in subtropical NW Africa during the time interval from ca. 4200 to 1200 cal yr BP. Our study emphasizes significant coeval changes in continental and oceanic environments in and off Senegal and shows that initial dry conditions were followed by a strong and rapid increase in humidity between ca. 2900 and 2500 cal yr BP. After ca. 2500 cal yr BP, the environment slowly became drier again as indicated by slight increases in Sahelian savannah and desert elements in the pollen record. Around ca. 2200 cal yr BP, this relatively dry period ended with periodic pulses of high terrigenous contributions and strong fluctuations in fern spore and river plume dinoflagellate cyst percentages as well as in the fluxes of pollen, dinoflagellate cysts, fresh-water algae and plant cuticles, suggesting “episodic flash flood” events of the Senegal River. The driest phase developed after about 2100 cal yr BP. 相似文献
146.
Karin Holmgren Jan Risberg Johan Freudendahl Mussa Achimo Anneli Ekblom Joao Mugabe Elin Norstr?m Sandra Sitoe 《Journal of Paleolimnology》2012,48(2):311-322
Stratigraphic variations in diatom composition and phytolith abundance in a sediment core from a small, hydrologically isolated waterbody, Lake Nhauhache, Mozambique, provide evidence of water-level fluctuations over the past ~2,300?years. Ten AMS radiocarbon dates on bulk sediment samples show that the lake came into existence about 2,300?years ago and that it has dried out since then, but only for brief time periods. Changes in the diatom assemblage composition indicate that lake level fluctuated in response to shifting humidity conditions. The changes reflect wetter conditions ca. 300 BC?CAD 800, more variable conditions between AD 800 and 1150, a distinct dry phase within the time span AD 1150?C1700 and a return thereafter to more humid conditions until present. There is general agreement between the Lake Nhauhache record and other records from the Southern Hemisphere summer rainfall region. This suggests that sediments from small interdunal lakes, which are abundant along the coast of southern Africa, provide reliable, regional paleoenvironmental information about an area from which more such data are needed. 相似文献
147.
Dr. Karin Dohnal 《Meteorology and Atmospheric Physics》1967,16(2-3):153-168
Zusammenfassung In der vorliegenden Arbeit wurde versucht, das Sutcliffesche Entwicklungstheorem auf dieV
b
-Wetterlage vom 8. und 9. Oktober 1964 anzuwenden. Dabei wurde dieses Theorem einer Kritik unterzogen und allgemeiner gefaßt. Die Anwendung ergab, daß die Entwicklung selbst dadurch nicht richtig erfaßt werden konnte, wohl aber das weitere Verhalten der Zyklone nach ihrer Entwicklung. Für die Entwicklung selbst spielen offenbar die Winddrehung mit der Höhe und der vertikale Vorticitytransport eine entscheidende Rolle, die bei der vorliegenden Untersuchung nicht berücksichtigt wurden.
Mit 2 Textabbildungen 相似文献
Summary In this paper Sutcliffe's theorem of development is applied to theV b -situation of October 8 and 9, 1964. Doing this the theorem has been critically revised and drafted in more generality. The application shows that the development cannot be explained by this theorem even in the more general drafting, however, the further behaviour of the cyclone after its development was in accordance to the theorem. For the development itself, obviously, the vertical windshear and the vertical transport of vorticity are dominating, both of which were not taken into consideration in the present investigation.
Résumé Dans la présente étude, on cherche à appliquer le théorème de développement établi par Sutcliffe à la situation météorologique générale diteV b -cyclone des 8 et 9 octobre 1964. On saisit cette occasion pour soumettre le dit théorème à la critique et pour lui donner une forme plus générale. Cette application a montré qu'il n'était pas possible de bien saisir par là le développement de la situation lui-même, mais, par contre de déterminer le comportement du cyclone après le dit développement. Il semble que la rotation des vents avec l'altitude et le transport vertical de la puissance tourbillonnaire (vorticity) jouent un rôle déterminant pour l'évolution elle-même de la situation. Ce rôle n'a cependant pas été pris en considération dans la présente étude.
Mit 2 Textabbildungen 相似文献
148.
Imbricate reflections commonly occur in the glacigenic section of seismic profiles from the Bjørnøya Trough. This was the main drainage pathway for fast‐flowing ice‐streams from the former Barents Sea and Scandinavian ice sheets. Industry three‐dimensional (3D) seismic data from the southern flank of the Bjørnøya Trough are used here to investigate these imbricate reflections. Integration of vertical seismic sections with 3D plan view images and attribute maps reveal that imbricate reflections at the SW Barents Sea Margin are mega‐scale sediment blocks with a glacigenic origin. Imbricate reflections in two regions to the east of the survey appear on plan‐view as well‐developed lineations of U‐shaped crescents; however, following detailed analysis of their location, geometry and relation to sailing direction during data acquisition, we can demonstrate that these are seismic artefacts. These artefacts are related to the straight parts of east–west‐trending plough marks on the sea floor, having a dip direction that is directly related to the sailing direction of the ship during seismic acquisition. By analysing both real glacigenic imbrications and false imbrications or artefacts, we are able to demonstrate the critical distinguishing criterion. 相似文献
149.
美国需要改进干旱监测与评估方法。干旱是代价昂贵的自然灾害(联邦应急管理局(FEMA),1995;W ilhite,2000),但经常被评估和预报产品的开发者忽略。相比于其他灾害,干旱表现得更模糊并且不适合用传统的评估或预报方法,它相对缓慢的发生以及其影响的复杂性,需要有一套新的方法来对它进行评估。干旱监测和预报技术的提高会使我们为应对干旱灾害做更好的准备工作,进行更好的应对实践,从而减少社会对干旱及其影响的脆弱性。为追踪和展示全美国干旱的程度、空间范围以及其影响,开发了新的干旱监测工具,研发了每周发布的国家级干旱监测业务产品(th… 相似文献
150.
Os, Sr, Nd and Pb isotope data were collected from a profile across the Cretaceous-Tertiary (K-T) boundary layer at Stevns Klint, Denmark. ?Nd [T=65 Ma] values from within the boundary layer (Fish Clay) are lower by ∼1 ? unit than those of the underlying Maastrichtian limestone and the overlying Danian chalk sequences. Systematic profile-upward changes of Pb, Sr and Os isotopic compositions and concentrations in the boundary layer cannot be accounted for by in situ growth of daughter products since the sedimentation of the Fish Clay. While Os, Nd and Pb isotopes indicate the admixing of less radiogenic components to the Fish Clay, Sr isotopes show elevated radiogenic values in the boundary layer, relative to the carbonate sequences beneath and above it. The sudden change in lithophile (e.g., Sr, Pb and Nd) isotope compositions at the base of the Fish Clay and profile-upward trends of 87Sr/86Sr and 206Pb/204Pb ratios towards those of the overlying Danian chalk are interpreted to reflect recovery from enhanced, acid rain-induced continental (local?) weathering input to the seawater. However, a continental crustal source is invalid for the siderophile element Os. In the light of evidence from chromium isotopes for a cosmic origin of the platinum group elements (PGEs) and certain moderately siderophile elements (Cr, Ni, Co, V) in K-T boundary sediments, including Stevns Klint [Shukolyukov and Lugmair, Science 282 (1998) 927-929], and supported by the finding of projectile debris [Bauluz et al., Earth Planet. Sci. Lett. 182 (2000) 127-136] and the occurrence of abundant Ni-rich spinel at many K-T sites [Robin et al., Nature 363 (1993) 615-617; Kyte, Nature 396 (1998) 237-239], we favor to explain the sudden drop of 187Os/188Os ratios from 0.210 to 0.160 at the K-T boundary to derive from global fall-out of extraterrestrial matter. The present 186Os/188Os ratio of 0.119836±0.000004 measured in the basal layer of the Fish Clay is within the uncertainty a chondritic value. We therefore exclude the possibility of a major contribution of PGEs to the sediment from iron meteorites. Chondrite-normalized (Ru/Ir)N ratios of ∼0.95±0.14 and (Os/Ir)N ratios of ∼0.93±0.14 in the Fish Clay cannot distinguish between abundance ratios of different types of chondrites, and strongly sub-chondritic (Pt/Ir)N ratios of ∼0.62±0.09 (2σ) suggest differential PGE remobilization through the sedimentary column (and consequently the alteration of inter-element ratios). PGEs and the moderately siderophile elements Cr, Ni, V, and Co form an elemental association with systematically upward-decreasing concentrations in the Fish Clay. Low Co/Ni ratios of ∼0.12 in the Fish Clay relative to values of ∼0.35 in the over- and underlying carbonate sequences support mixing of meteorite-derived (Co/Ni ∼0.05) and terrestrial upper mantle/crustal (Co/Ni >∼0.3) sources. While lithophile element isotope data indicate an increased continental crustal input to the Fish Clay at the K-T transition, the uncertainty with respect to possible post-depositional alteration of abundance patterns of siderophile and moderately siderophile elements - though not affecting the chondritic isotopic composition of Os - does not allow confirmation of indications from chromium isotopes for a carbonaceous (CV-type) meteorite as the preferred K-T impactor type by Shukolyukov and Lugmair [Science 282 (1998) 927-929]. 相似文献