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  • 1
    Online Resource
    Online Resource
    Berlin ; Heidelberg : Springer-Verlag
    Keywords: Medizin ; Englisch ; Fachsprache ; Medizin ; Internal medicine ; Medicine ; Einführung ; Englisch ; Fachsprache ; Medizin
    Type of Medium: Online Resource
    Pages: 1 Online-Ressource (XIX, 506 S.)
    ISBN: 9783540496182
    URL: Volltext  (URL des Erstveröffentlichers)
    RVK:
    Language: English
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Water, air & soil pollution 19 (1983), S. 389-395 
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract A shortage of land in some urban areas has resulted in the use of hydro corridors for garden plots. Corrosion of the galvanized steel towers (hydro towers) which support electrical transmission lines causes Zn contamination of soils and may result in uptake and concentration of the metal by plants. Furthermore, the Zn used in hot dip galvanizing may be contaminated with Cd. To determine if vegetables accumulate and are affected by Zn and Cd corroded from hydro towers, soil was collected from near hydro towers, to grow lettuce and radish in a glasshouse pot experiment. Plants grown in soil collected 1 m from a tower had concentrations of Zn 5 to 10 times higher than in plants grown in garden soil collected 10 and 90 m from a tower but concentrations were not high enough to have apparent toxic effects on growth. Concentrations of Cd in the soils, lettuce and radish plants indicated that the particular towers were not a source of Cd contamination.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Water, air & soil pollution 37 (1988), S. 355-363 
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Corn kernels and young corn plants (Zea mays) growing beneath and close to a 6-yr old galvanized steel tower supporting a 500-kV electrical transmission line had elevated concentrations of Zn due to corrosion of the protective Zn coating on the steel. Zinc corrodes preferentially from galvanized steel and as a result, protects the underlying metal from rusting (sacrificial protection). Corn plants growing beneath and close to towers absorb Zn from soil contaminated by runoff from the lattice towers and from falling water droplets. Corn seedlings (7-wk old) grown in highly contaminated soil (1425 ± 264 μ g−1) collected near a 30-yr old tower had much higher concentrations of Zn than did plants (8-wk old) growing near and under the 6-yr old tower. The concentrations of Zn found in plants were not high enough to be hazardous to domestic animals and contamination of soil was localised around the towers studied. Cd does not appear to be accumulating in soils or plants near the towers.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 161 (1988), S. 271-274 
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 214 (1991), S. 149-154 
    ISSN: 1573-5117
    Keywords: palaeolimnology ; sediments ; heavy metal pollution ; Cu and Zn ; land-use ; crops ; Industrial Revolution ; Napoleonic Wars ; Wales
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Elevated concentrations of Cu and Zn have been found in the upper part of three sediment cores collected from Llangorse Lake, in south Wales. Palaeomagnetic evidence from one of the cores and 210Pb analysis of another, suggests that the increase in sediment Cu and Zn concentrations began during the eighteenth century. A sharp increase in the concentrations of these metals in the sediment profile appears to have occurred during the latter part of the eighteenth century and these concentrations remained high until the mid to late nineteenth century. The absence of known ore deposits and industry around the lake suggests that the lake and catchment soils were increasingly contaminated by long-range aerial transport of emissions from the expanding activity of Cu and Zn smelters located some 80 km upwind in the Swansea area during the Industrial Revolution. Evidence from agricultural crop returns indicates a significant increase in the amount of land devoted to tillage in the catchment, particularly to cereal production, during the late eighteenth and the first half of the nineteenth century which included the Napoleonic Wars. This agricultural shift appears to coincide with increased concentrations of Cu and Zn in the lake sediments. It is suggested that newly ploughed soils, contaminated with metals for many years by long-range aerial transport from the Swansea area, eroded, and were carried into the lake by catchment run-off and added to the sediment burden of Cu and Zn. A subsequent decline of Cu and Zn emissions due to the collapse of the non-ferrous smelting industry and reduced soil erosion because of a 50% reduction of tillage due to an agricultural depression in the second half of the 19th century may explain the fall in Cu and Zn concentrations in the upper part of the sediment profile. The most recent sediments (20th century) show the increase in heavy metals characteristic of many lakes around the world.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 47 (1975), S. 431-437 
    ISSN: 1573-5117
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A freshwater sampler using five sterile evacuated glass tubes is described. Water enters when a rubber stopper is mechanically removed from the end of a sterile hypodermic needle inserted into each tube. Plate counts of bacterial colonies were compared with those obtained with other samplers.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 229 (1992), S. 73-91 
    ISSN: 1573-5117
    Keywords: lakes ; humic substances ; plankton ; food chains
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Humic substances (HS) might influence planktonic food chains in lakes in two ways: 1) by altering the physical or chemical environment and thus modifying autotrophic primary production and the dependent food chains; 2) by acting as a direct carbon/energy source for food chains. HS compete with phytoplankton for available quanta underwater and this effect is seen in the reduced euphotic zone depth in lakes with high concentrations of HS. Thus potential photosynthetic production is lower in the presence of HS. However, this effect can be offset in small lakes in which the depth of mixing is also reduced when HS concentrations are high. Complexation by HS of important nutrients such as iron and phosphorus may also restrict primary production. Evidence is accumulating that photosynthetic primary production is insufficient to support measured metabolic activity in humic lakes, which implies that metabolism of allochthonous HS underpins much of the observed activity. Studies of bacterial abundance and growth in the presence of HS support the view that bacteria are the most significant utilisers of HS. This use is apparently facilitated by photolysis of HS, particularly by short wavelength radiation. Bacteria are grazed by both micro-zooplankton (heterotrophic and mixotrophic flagellates and ciliates) and macrozooplankton. It is within this microbial community that the food chains derived from autotrophic and allotrophic sources interact. These effects of HS on food chains are discussed in relation to possible implications for the response of different lake types to eutrophication.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Journal of biomolecular NMR 9 (1997), S. 55-62 
    ISSN: 1573-5001
    Keywords: Site-specific labeling of RNA ; 15N labeling of guanine and adenine ; Inosine-for-guanine substitution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The secondary structure of a recently identified ATP-binding RNA aptamer consists of apurine-rich 11-residue internal loop positioned opposite a single guanine bulge flanked oneither side by helical stem segments. The ATP ligand targets the internal loop and bulgedomains, inducing a structural transition in this RNA segment on complex formation.Specifically, 10 new slowly exchanging proton resonances in the imino, amino and sugarhydroxyl chemical shift range are observed on AMP–RNA aptamer complex formation.This paper outlines site-specific labeling approaches to identify slowly exchanging imino(guanine) and amino (guanine and adenine) protons in internal loop and bulge segments ofcompact RNA folds such as found in the AMP–RNA aptamer complex. One approachincorporates 15N-labeled guanine (N1 imino and N2 amino positions) and 15N-labeledadenine (N6 amino position), one residue at a time, in the AMP-binding RNA aptamer, withlabeling incorporation through chemical synthesis facilitated by generating the aptamer fromtwo separate strands. The unambiguous assignments deduced from the 15N labeling studieshave been verified from an independent labeling strategy where individual guanines in theinternal loop have been replaced, one at a time, by inosines and assignments were made onthe basis of the large 2 ppm downfield shift of the guanine imino protons on inosinesubstitution. The strengths and limitations of the inosine-for-guanine substitution approachemerge from our studies on the AMP–RNA aptamer complex. The assignment of theinternal loop and bulge imino and amino protons was critical in our efforts to define thesolution structure of the AMP–RNA aptamer complex since these slowly exchangingprotons exhibit a large number of long-range intramolecular NOEs within the RNA, as wellas intermolecular NOEs to the AMP in the complex. The current application of specific 15Nand inosine labeling approaches for exchangeable imino and amino proton assignments in thenonhelical segments of an RNA aptamer complex in our laboratory complements selective 2Hand 13C approaches to assign nonexchangeable base and sugar protons in RNA andligand–RNA complexes reported in the literature.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 243-244 (1992), S. 105-111 
    ISSN: 1573-5117
    Keywords: phosphorus ; transformations ; humic forest lake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Research on epilimnetic phosphorus transformations in lakes had led to the establishment of a generalised picture which is promoted in reviews and textbooks. However, it would be wrong to believe that this established view can be applied to all lakes. Certainly the transformations of phosphorus in the summer epilimnia of small, coloured, humic forest lakes in southern Finland show features which deviate markedly from the generally accepted paradigm. (1) The plankton appears to be limited simultaneously by P and N rather than being strongly P limited. (2) Particulate P is typically a rather small fraction of the total P. (3) Molybdate reactive P may be a large part of the total P, although much of this MRP is not free orthophosphate, especially in highly humic lakes. (4) Turnover times for PO4-P are normally long (50–1000 minutes); turnover times appear to be longer in highly humic lakes. (5) Added 32 PO4 passes rapidly to macrozooplankton, apparently with rapid turnover of zooplankton phosphorus. (6) Sedimentation of phosphorus from the typically shallow epilimnion appears high, but may be partially compensated by biological retrieval of phosphorus from the phosphorus-rich hypolimnion.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 62 (1979), S. 55-58 
    ISSN: 1573-5117
    Keywords: Aphanizomenon flos-aquae ; perennation ; akinete production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Aphanizomenon flos-aquae contributed regularly to the summer phytoplankton in Kinnego Bay, a highly eutrophic part of Lough Neagh. Growth of the alga was variable in different years, and was apparently related to the duration of depletion of dissolved nitrate-nitrogen in the water. Although four growth pulses occurred during the study period, sporulation was only observed during one of these, when the population was very dense although evenly distributed down the water column. It seems that Aphanizomenon overwintered in Kinnego Bay as vegetative filaments and that production of akinetes was not necessary for perennation of the species. The observed sporulation in 1973 may have been induced by the high pH values caused by dense phytoplankton crops; no other measured environmental factors were particularly unfavourable to growth of Aphanizomenon at this time.
    Type of Medium: Electronic Resource
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