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91.
Rainbow trout were exposed to 200 ppb cadmium in the water during four months at 5°C. The liver, kidney and gills were analyzed for cadmium, copper, zinc and metallothionein. Cadmium accumulated in all three organs and reached the highest concentration in the kidney. The zinc and copper concentrations were not altered during the experiment. The metallothionein concentration was significantly higher in liver of exposed fish than in control fish after three months. The kidneys reached significantly elevated levels of metallothionein in the exposed group after four months. These results demonstrate that metallothionein is induced by cadmium after exposure to the metal via water. 相似文献
92.
An extensive trial to examine physiological and biochemical changes in perch (Perca fluviatilis) inhabiting coastal waters polluted by bleached kraft mill effluents has been carried out. The results from this investigation show profound effects of bleached kraft mill effluents on several fundamental biochemical and physiological functions on four different sampling occasions. Typical symptoms in perch from the polluted areas were reduced gonad growth, enlarged liver, and very strong induction of certain cytochrome P-450-dependent activities. Elevated content of ascorbic acid in liver tissue and strongly affected carbohydrate metabolism show that the effluent causes metabolic disorders. Marked effects on the white blood cell pattern indicate a suppressed immune defence. Alterations in the red blood cell status and the ion balance suggest an impaired gill function. This extensive symptom picture is strengthened by the relatively good agreement with the effects previously observed in fish exposed to bleached kraft mill effluents (BKME) in the laboratory.1–3 相似文献
93.
Summary A new method is described for deriving values of the natural illumination of direct solar radiation from measurements of the
latter, integrally with regard to wavelength and, simultaneously, in well-defined spectral regions. The basic equations are
presented and graphical comparisons between data so computed and observed analyzed. The degree of prediction of individual
short-period values of direct illumination flux (e. g. half-hourly intervals), established for wide ranges of solar height
and turbidity, is of the same order as the accuracy generally expected in such series of carefully conducted measurement programs.
This technique of employing radiometric rather than photometric measurements is thus shown to have a general application.
With 3 Figures
Dedicated to Dr.W. M?rikofer on the occasion of his 70th birthday. 相似文献
Zusammenfassung Es wird eine neue Methode zur Berechnung von Werten der natürlichen Beleuchtungsst?rke durch die direkte Sonnenstrahlung aus Messungen der letzteren abgeleitet, und zwar gleichzeitig für das gesamte Spektrum und für genau abgegrenzte Spektralbereiche. Es werden die Grundgleichungen angegeben und graphische Vergleiche zwischen den so berechneten und den beobachteten Werten durchgeführt. Einzelwerte des direkten Lichtstromes über kurze Zeiten (z. B. Halbstundenintervalle), die für gro?e Bereiche von Sonnenh?he und Trübung berechnet wurden, haben denselben Genauigkeitsgrad, wie man ihn bei sorgf?ltig ausgeführten Me?programmen gew?hnlich erwartet. Damit ist erwiesen, da? die Methode, Strahlungsmessungen statt Lichtmessungen zu verwenden, allgemein angewendet werden kann.
Résumé Les auteurs exposent ici une nouvelle méthode permettant de calculer l'intensité lumineuse naturelle du rayonnement solaire direct au moyen de la mesure de ce dernier. Cette méthode permet le calcul aussi bien pour la totalité du spectre que pour certaines bandes délimitées. Les auteurs indiquent les équations de base et donnent des comparaisons graphiques entre des valeurs observeés et calculées de cette manière. Les valeurs isolées du flux lumineux direct regu en des laps de temps brefs (par exemple dúne demie-heure), valeurs calculées pour de grands intervalles aussi bien de la hauteur du soleil que du trouble atmosphérique, donnent le même degré déxactitude que celui quón peut attendre de mesures directés effectées soigneusement. On a ainsi démontré que la méthode qui consiste à utiliser des mesures du rayonnement au lieu de la luminosité peut être utilisée de fa?on trés g&&ale.
With 3 Figures
Dedicated to Dr.W. M?rikofer on the occasion of his 70th birthday. 相似文献
94.
95.
MARK D. JOHNSON YLVA STÅHL 《Boreas: An International Journal of Quaternary Research》2010,39(2):199-214
Johnson, M. D. & Ståhl, Y. 2009: Stratigraphy, sedimentology, age and palaeoenvironment of marine varved clay in the Middle Swedish end‐moraine zone. Boreas, 10.1111/j.1502‐3885.2009.00124.x. ISSN 0300‐9483 Deglaciation of the Middle Swedish end‐moraine zone and age of the sediment in and between the moraines have been discussed for about a hundred years. The goal of this project was to determine the stratigraphy and age of the sediment in and between the moraines. Inter‐moraine flats are underlain by clay, 10–25 m thick, overlying thin sand and gravel or till on bedrock. The clay is overlain by a few metres of sand and gravel. Much of the clay beneath the flats consists of rhythmites that grade from grey to red and are 2–74 cm thick. Our interpretation of these rhythmites as being varves is supported by grain size and mineralogical and elemental variations. Foraminifera and ostracods show that the clay was deposited in an arctic marine environment, while radiocarbon dating of the microfossils indicates that the clay was deposited 12 150 cal. 14C years ago, during the Younger Dryas chronozone (YD). Most of the optical stimulated luminescence dates on the clay are much older, containing quartz sand that was insufficiently bleached. The stratigraphy indicates that the moraines are composed of YD clay pushed into ridge forms during ice‐front oscillations. It is not possible to determine how far north the Scandinavian Ice Sheet retreated prior to the YD advance. We neither support nor reject the suggestion that the ice margin retreated to the northern edge of Mt. Billingen during the Allerød, causing the Baltic Ice Lake to drain. 相似文献
96.
Søren Erbs Poulsen Keld Rømer Rasmussen Niels Bøie Christensen Steen Christensen 《Hydrogeology Journal》2010,18(1):161-171
A monitoring system, including five groups of piezometers and five vertical multielectrode profiling probes (VMEP), has been installed in an aquifer beneath a coastal dune in Denmark. In order to assess the salinity distribution within the aquifer, geoelectrical data were gathered in March, June and September 2008, by measuring a dipole-dipole and gradient array using multielectrode profiling. Interpretation of the processed resistivity data was performed by regularized inversion using a one-dimensional, horizontally layered model of formation resistivity. The standard deviation on estimated layer log-resistivity was 0.01–0.03. By estimating two parameters of a power function, observed fluid conductivities derived from samples of porewater were related to corresponding estimated formation resistivities. The conductivity profiles correlate with a winter situation in March with high sea level, active recharge and significant wave activity, causing increased hydraulic heads, a thicker freshwater lens and salt water overlying freshwater close to the sea. In June, the thickness of the freshwater lens is reduced due to less recharge and prevailing offshore winds, imposing density-stable conditions and a sharper transition between fresh and brackish water. During the autumn, aquifer recharge is enhanced and hydraulic heads increase, resulting in a thicker freshwater lens. 相似文献
97.
Ida Bülow Gregersen Hjalte Jomo Danielsen Sørup Henrik Madsen Dan Rosbjerg Peter Steen Mikkelsen Karsten Arnbjerg-Nielsen 《Climatic change》2013,118(3-4):783-797
Climate change is expected to influence the occurrence and magnitude of rainfall extremes and hence the flood risks in cities. Major impacts of an increased pluvial flood risk are expected to occur at hourly and sub-hourly resolutions. This makes convective storms the dominant rainfall type in relation to urban flooding. The present study focuses on high-resolution regional climate model (RCM) skill in simulating sub-daily rainfall extremes. Temporal and spatial characteristics of output from three different RCM simulations with 25 km resolution are compared to point rainfall extremes estimated from observed data. The applied RCM data sets represent two different models and two different types of forcing. Temporal changes in observed extreme point rainfall are partly reproduced by the RCM RACMO when forced by ERA40 re-analysis data. Two ECHAM forced simulations show similar increases in the occurrence of rainfall extremes of over a 150-year period, but significantly different changes in the magnitudes. The physical processes behind convective rainfall extremes generate a distinctive spatial inter-site correlation structure for extreme events. All analysed RCM rainfall extremes, however, show a clear deviation from this correlation structure for sub-daily rainfalls, partly because RCM output represents areal rainfall intensities and partly due to well-known inadequacies in the convective parameterization of RCMs. The results highlight the problem urban designers are facing when using RCM output. The paper takes the first step towards a methodology by which RCM performance and other downscaling methods can be assessed in relation to the simulation of short-duration rainfall extremes. 相似文献
98.
Fundamental differences between SPH and grid methods 总被引:1,自引:0,他引:1
Oscar Agertz Ben Moore Joachim Stadel Doug Potter Francesco Miniati Justin Read Lucio Mayer Artur Gawryszczak rey Kravtsov Åke Nordlund Frazer Pearce Vicent Quilis Douglas Rudd Volker Springel James Stone Elizabeth Tasker Romain Teyssier James Wadsley Rolf Walder 《Monthly notices of the Royal Astronomical Society》2007,380(3):963-978
99.
Åke Johansson David G. Gee Alexander N. Larionov Yoshihide Ohta Alexander M. Tebenkov 《地学学报》2005,17(4):317-325
Svalbard is located in the north-west corner of the Barents Sea shelf and the Eurasian Plate, in a key area for interpreting Caledonian and older orogens in the Arctic region. Recent U–Pb dating in the Nordaustlandet Terrane of eastern Svalbard shows this terrane to consist of a Grenville-age basement, overlain by Neoproterozoic to early Palaeozoic platformal sediments, and intruded by Caledonian anatectic granites. Deformation, metamorphism and crustal anatectic magmatism occurred both during the Grenvillian (960–940 Ma) and Caledonian (450–410 Ma) orogenies. This evolution shows great similarities with that of eastern Greenland. In the classical model, eastern Svalbard is placed outboard of central east Greenland in pre-Caledonian time. Alternatively, it may have been located north-east of Greenland and transferred west and rotated anticlockwise during Caledonian continent–continent collision. In the Neoproterozoic, easternmost Svalbard may have been part of a wider area of Grenville-age crust, now fragmented and dispersed around the Arctic. 相似文献
100.
Patricia Fernndez-Calvo Christian Nke Luis A. Rivas Miriam García-Villadangos Javier Gmez-Elvira Víctor Parro 《Planetary and Space Science》2006,54(15):1612-1621
We have developed antibodies and a multi-array competitive immunoassay (MACIA) for the detection of a wide range of molecular size compounds, from single aromatic ring derivatives or polycyclic aromatic hydrocarbons (PAHs), through small peptides, proteins or whole cells (spores). Multiple microarrays containing target molecules are used simultaneously to run several competitive immunoassays. The sensitivity of the MACIA for small organic compounds like naphthalene, 4-phenilphenol or 4-tertbutilphenol is in the range of 100–500 ppb (ng ml−1), for others like the insecticide terbutryn it is at the ppt (ng l−1) level, while for small peptides, as well as for more complex molecules like the protein thioredoxin, the sensitivity is approximately 1–2 ppb, or 104–105 spores of Bacillus subtilis per milliliter. For organic compounds, a water–methanol solution was used in order to achieve a better dissolution of the organics without compromising the antibody–antigen interaction. The above-mentioned compounds were detected by MACIA in water–(10%) methanol extracts from spiked pyrite and hematite-containing rock powder samples, as well as from a spiked-sand sample subjected to organic extraction with dichloromethane–methanol (1/1). 相似文献