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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 115 (1993), S. 331-338 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Trace metals were analyzed in the muscle and other organs from several species of deep-water sharks (particularly Centrophorus granulosus and Galeus melastomus) from 1280 to 1500 m depth in the eastern Mediterranean between 1985 and 1991. As has been shown with other pelagic fish, there was a significant correlation between specimen size and the mercury concentration in the muscle as well as in the liver and kidneys. For a given size, the level of mercury in sharks from the eastern Mediterranean was considerably higher compared with the same species caught off the west coast of Italy. There was no significant correlation between the concentrations of Cd, Cu, Zn and Fe in the muscle (or other organs) and body size. The overall trace metal content was considerably higher in the specimens from the eastern Mediterranean compared with the same species from the N. E. Atlantic. It is suggested that these higher-than-expected trace metal levels might be due to a relatively high trace metal content in the waters of the region or to the unusual physiology of these fish, possibly related to the extreme oligotrophic conditions in the area.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Marine biology 25 (1974), S. 339-343 
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A sampler is described which can be used for the collection of microbiological, phytoplanktological, and chemical sea-water samples. The sampler consist of a polyvinylchloride (PVC) frame on which a sterile silicone-rubber container (500 ml) is assembled. The sampler is fitted with a couple of reversing thermometers. All materials used, including the hydrographic cable and the messenger, have been tested for toxicity. The container, actuated by the messenger, fills and then is closed by a stop-cock to prevent any contamination with upper-level sea water during hauling aboard. The reversing thermometers reverse only when the sample has been taken properly. Thus, the thermometers guarantee good functioning of the sampler and supply also information on the exact depth at which the sample was collected. The device can operate at any depth and several devices can be operated in one cast. During normal operation, contamination due to microorganisms attached to the frame and container is negligible.
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  • 3
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sampling performance of two high-speed samplers, (Delfino I and II), fitted with a calibrated flow meter, was studied in the open Ligurian Sea using a battery comprising 6 such Delfinos linked together. Since, in plankton counts, only those organisms should be counted which are definitely retained in the nets, several techniques for the separation of the organisms which pass through the pore of a net of a given pore size and those which are safely retained were tested. Attempts to separate these two fractions by filtration of the fixed sample through nets of different pore sizes were not successful, as living organisms were able to pass through pore sizes which retained dead organisms. However, optical sizing under the dissecting microscope during counting gave reproducible results. Using this counting technique, the influence of the pore size of plankton nets on the reproducibility of sampling of natural populations was studied. The results obtained show that live plankton passes through the net pores at a size at which fixed plankton is retained. Hence, the minimum retention size for living and dead plankton is different. By comparing samples taken with nets of different pore sizes, and counting the organisms caught according to different sizes, it was possible to determine the minimum retention size of live plankton organisms for several different net pore-sizes. The minimum retention size is, therefore, the smallest pore size at which the organisms of a certain width cannot escape through the pores of the net and are, thus, quantitatively retained in the net. By applying the criterion of minimum retention size, the influence of speed towing on the number of plankton organisms caught was studied. It was shown that the number of organisms which are safely retained, i.e., do not escape through the pores, increased with speed, reaching a plateau at 5 to 7 knots.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Solar physics 99 (1985), S. 101-109 
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In the solar corona the opacities of some of the prominent X-ray emission lines are on the order of τ ≈ 1 over typical coronal path lengths. We present and discuss a particular solution of the radiative transfer problem involving an extended, spherically symmetric coronal shell radiating isotropic, homogeneous emission in which single-scattering also takes place. Within the context of this simplified model we find that scattered radiation is an important contribution to the total emergent resonance line flux and that for the He-like family of resonance (r), intercombination (i), and forbidden (f) lines, the ratio G=(f + i)/r would decrease as a function of optical depth for disk-center emission in an extended spherically symmetric corona.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Helgoland marine research 20 (1970), S. 655-675 
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary 1. Using 6 phytoplankton species and/or the copepodEuterpina acutifrons or larvae of the sea urchinArbacia lixula the potential inhibitory effects of chemicals released from some 70 different materials (mainly plastics) have been tested. In addition, the effects of 6 detergents have been examined. 2. Several materials, such as natural rubbers and polyvinyl chlorides, are highly toxic and should never be used when experimenting with living marine organisms. 3. Teflon (Algoflon), Perspex, Polyethylene, Tygon, Polypropylene, Polycarbonates (Makrolon) and Polyester (Gabraster) have been shown to be non-toxic and are, therefore, suitable for use in cultivation of marine organisms. Some materials had slightly negative effects on the organisms tested and should, therefore, be used only if no alternatives are available. 4. Some suggestions are advanced on how to construct non-toxic samplers and laboratory equipment used for experiments with marine organisms.
    Notes: Kurzfassung Etwa 80 chemisch verschiedene Substanzen und Materialien wurden hinsichtlich einer möglichen toxischen Wirkung an mehreren Phytoplanktonarten, dem CopepodenEuterpina acutifrons und den Larven des SeeigelsArbacia lixula geprüft. Es zeigte sich, daß die Phytoplankter empfindlichere Testorganismen sind alsEuterpina acutifrons und die Larven vonArbacia lixula. Auch konnte zwischen den verschiedenen Phytoplanktonarten erhebliche Unterschiede in der Reaktion festgestellt werden. Detergentien erwiesen sich nur in relativ hohen Konzentrationen als toxisch. Viele Substanzen, die eine mannigfache Anwendung im Laboratorium finden, wie zum Beispiel roter und schwarzer Gummi oder Polyvinylchlorid, sind ausgesprochen toxisch und sollten nicht für Geräte benutzt werden, die zur Probeentnahme lebender Organismen dienen. Einige Substanzen, die sich zunächst als nicht toxisch erwiesen hatten, wurden toxisch, nachdem sie bei 0,5 atm 20 min in dem Kulturmedium sterilisiert wurden. Es konnte jedoch nachgewiesen werden, daß Polyäthylene (naturfarben), Gabraster (mit Katalysatoren), Perspex, Silicongummi, Algoflon (Teflon), Tygon, Silikon SE 1201 und Kautschuk (für Stöpsel) auch nach dem Sterilisieren optimales Wachstum der Testorganismen zulassen. Da aber Firmen oft die Zusammensetzung ihrer Materialien ändern, müssen die einzelnen Lieferungen immer wieder auf Toxizität geprüft werden. Nur so kann verhindert werden, daß Wasserschöpfer, Planktonnetze und andere Geräte, die zur Probenentnahme von lebenden Organismen benutzt werden, die Organismen nicht bereits negativ beeinflussen, bevor das eigentliche Experiment angesetzt worden ist. Das gleiche gilt natürlich auch für Materialien, die zur Konstruktion der Kulturgefäße und-apparate benutzt werden.
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  • 6
    ISSN: 1436-5073
    Keywords: Auger electron spectroscopy ; iron ; surface segregation ; single crystal surfaces
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The analysis of segregation phenomena in bicrystals is an important step for the understanding of combined effects of the elementary diffusion processes involved in the segregation in polycristalline systems. The segregation of Si and P in a Fe-6at.%Si bicrystal with a (100) and (110) surface has been investigated by means of AES (Auger electron spectroscopy). For these experiments the technique of a linearly increased temperature has been applied. Significant differences between the segregation kinetics at the two surfaces of the sample have been found on the one hand for the maximum coverage of P and on the other hand for the high temperature behaviour of Si. Additionally, model calculations based on the KTBIM (kinetic tight binding Ising model) have been performed to qualitatively describe the experimental results. It is shown, that the striking differences between the segregation behaviour at the two differently oriented surfaces can be explained by different segregation energies of P, whereas Si plays a minor role due to its relatively small segregation energy.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Solar physics 121 (1989), S. 1-2 
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Solar physics 121 (1989), S. 3-18 
    ISSN: 1573-093X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract An overview of the many topics discussed at IAU Colloquium No. 104 is presented as an introduction to the Proceedings. Suggested areas for future research emerging from the conference are summarized.
    Type of Medium: Electronic Resource
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  • 9
    Publication Date: 2006-05-20
    Print ISSN: 1618-2642
    Electronic ISSN: 1618-2650
    Topics: Chemistry and Pharmacology
    Published by Springer
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  • 10
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