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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 64 (1988), S. 3193-3200 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A method is presented to analyze complex glow curves composed of several, possibly overlapping, peaks from thermally stimulated processes of general kinetic order and is applicable when the process studied is activated using any arbitrary temperature profile. A theoretical analysis is given to determine the properties of a single glow curve peak. Several new results are presented, among which is an expression for the peak temperature for general kinetic order and temperature profile. From the theoretical analysis of the asymmetry of a glow peak a method is described to determine the kinetic order of a peak and to obtain an initial estimate of the peak parameters sufficiently accurate to start a least-squares minimization procedure to determine the actual parameters of all peaks present in the total glow curve. The method is demonstrated for a synthetic glow curve and for two measured glow curves from a thermoluminescence experiment and a thermal gas desorption experiment.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: : Strenuous exercise exacerbates gastro-oesophageal reflux and symptoms and this may be diminished by antisecretory medication with omeprazole.〈section xml:id="abs1-2"〉〈title type="main"〉Methods: Fourteen well-trained athletes (13 men, one woman), who indicated suffering from either heartburn, regurgitation or chest pain during competition running, performed two experimental trials at 2-week intervals using a randomized, double-blind, placebo-controlled crossover design. During the 6 days preceding the trial and on the trial day itself either 20 mg of omeprazole or a placebo was administered. Two hours after a low-fat breakfast and 1 h after the last study dose, the trial started with five successive 50-min periods: rest, three running periods on a treadmill, and recovery. Reflux (percentage time and number of periods oesophageal pH 〈 4) was measured with an ambulant pH system during these periods.〈section xml:id="abs1-3"〉〈title type="main"〉Results: Compared to rest, reflux lasted significantly longer and occurred more frequently during the first running period, irrespective of the intervention, whereas during the second running period this effect was only observed with the placebo. Reflux occurred for longer and more frequently with the placebo than with omeprazole, but this was significant during the first two running periods only. Seven subjects reported heartburn, regurgitation and/or chest pain during exercise, irrespective of the intervention. Only a minority of the symptom periods was actually associated with acid reflux and in all cases this concerned periods with heartburn.〈section xml:id="abs1-4"〉〈title type="main"〉Conclusions: Running-induced acid reflux, but not symptoms, were decreased by omeprazole, probably because most symptoms were not related to acid reflux.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Biochimica et Biophysica Acta (BBA)/General Subjects 136 (1967), S. 415-425 
    ISSN: 0304-4165
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-0867
    Keywords: scale ; aggregation ; model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Different soil acidification models have been developed for use on different scales, i.e. NUCSAM for the local scale, RESAM for the regional (national) scale and SMART for the continental scale. This paper focuses on the uncertainties associated with scale transfer by a simpler model description by (i) temporal aggregation of process descriptions, (ii) neglection of processes associated with vertical aggregation of soil layers and (iii) the use of less detailed formulations of processes (process aggregation) and by spatial aggregation of input data. Results obtained for simulations in acid (sandy) soils indicate that (i) temporal aggregation and process aggregation have a limited impact on the long-term (decades) annual response of soil solution chemistry to atmospheric deposition, (ii) vertical aggregation mainly affects predictions of solutes which show a strong concentration gradient with depth and (iii) spatial aggregation hardly affects the average output for a given forest/soil combination. However, ignoring the variability in input parameters, largely affects the frequency distribution of model outputs in a region. Results imply that model simplification is an adequate step in the upscaling of modelling results from a local to a regional scale.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-2932
    Keywords: critical load ; deposition ; heavy metals ; persistent organic pollutants ; soil quality ; water quality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract In the pilot study ESQUAD the impact of atmospheric deposition of three heavy metals (cadmium, copper and lead) and two persistent organic pollutants (benzo(a)-pyrene and lindane) on the quality of European soils and seawater has been calculated. Calculations have been made of atmospheric transport and deposition using a detailed emissions database for Europe. This enabled deposition maps to be produced to a resolution of approximately 50 km. The distribution of pollutant concentrations in forest soils was calculated for each grid cell using a database of soil property parameters in Europe. For the North Sea, a model was used to map long-term concentrations in water and sediment, which are due to atmospheric deposition and other, non-atmospheric sources. The model calculations allowed detailed comparisons of deposition fluxes and concentrations of the substances studied with critical loads and environmental quality threshold values, including critical loads. Although significant uncertainties were identified, the study gives insight in how threshold exceedance rates in Europe relate to pollutant type, threshold type, environmental compartment and chemophysical phase (adsorbed, dissolved). For all pollutants and for all compartments exceedances were calculated for at least some of the quality thresholds that were chosen.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-2932
    Keywords: acidification ; assessment ; eutrophication ; Speulder forest ; vitality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Within the framework of the Dutch Priority Program on Acidification, 10 yr of research was conducted in a Douglas fir stand at Speulder forest. Research was conducted to establish the loads and levels of acidifying and eutrophying pollutants and ozone, to determine forest vitality characteristics and follow growth parameters and nutrient status in time and to determine the effects of reduction of loads and levels by manipulation experiments. Results indicate that during the last 20 yr critical levels for air pollutants have hardly been exceeded except for ozone, which slightly affected assimilation. Elevated nitrogen deposition has caused several adverse effects including (i) inhibited mycorrhizal development, leading to a decreased base cation and phosphorus uptake; (ii) elevated foliage/root (fine and coarse) ratios, making the forest more sensitive to drought and windthrow; (iii) elevated nitrogen and arginine concentrations in the foliage, associated with relative base cation and phosphorus deficiency, and (iv) elevated nitrate leaching polluting the groundwater. High inputs of acidity have caused elevated ratios of Al to base cations, affecting fine root (uptake) and depletion of the readily available Al pool, thus affecting the long-term sustainability. Despite these effects, forest vitality, in terms of defoliation/discoloration, is reasonable and forest growth even increased in response to nitrogen. The exceedances of critical loads for nitrogen and acidity, however, implies a (large) risk for the long-term sustainability of the Speulder forest.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-2932
    Keywords: aluminium depletion ; critical loads ; forest stands ; modelling ; nutrient cycling ; silicate weathering ; soil acidification ; sustainability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract To assess the impact of acid deposition on the long-term sustainability of nine oak, pine and spruce stands on sandy to loamy sandy parent material in Sweden, Denmark and The Netherlands, a dynamic soil acidification model (ReSAM) was applied. Two deposition scenarios for the period 1990–2090 were used: a business as usual scenario (BAU) and a restrictive critical load scenario (CL). The BAU scenario leads to a strong decrease in both Al concentrations and pH in the topsoil of the Dutch and the Danish sites due to a decrease in the amount of amorphous Al compounds. The decline in pH leads to an enhanced release of base cations by silicate weathering. Despite the ongoing acidification, base saturation increases during the simulation period, due to both the increase in base cation weathering and an increased input from mineralization with the ageing of the tree stands. No change in Al concentration is predicted for northern Sweden as deposition levels are below critical loads. Soil chemistry at the recently replanted Swedish sites is dominated by changes in N cycling instead of by deposition. The CL scenario leads, especially after 2010, to a stronger decline in Al concentration compared with the BAU scenario, which is mainly caused by a reduction of the acid input. Up to 2010, a considerable acid input to the soil system is maintained as N supply is larger than the consumption of N by the trees. Despite the reduction of the deposition of S and N to critical loads, the readily available cation pools are still declining on the Danish and Dutch sites in 2090. It is concluded that deposition levels above critical loads lead to exhaustion of the pool of amorphous Al compounds and a decline in pH. Base saturation does not decline due to an increase in mineralization with stand age and an increase in weathering rate due to the decline in pH.
    Type of Medium: Electronic Resource
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  • 8
    Publication Date: 2020-02-12
    Keywords: 550 - Earth sciences
    Type: info:eu-repo/semantics/article
    Format: application/pdf
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  • 9
    Publication Date: 2016-06-01
    Description: Daniel Messerschmidt, Wilhelmine N. de Vries, Chanchao Lorthongpanich, Sathish Balu, Davor Solter, and Barbara B. Knowles β-catenin (CTNNB1) is integral to cell adhesion and to the canonical Wnt signaling pathway. The effects of maternal and zygotic CTNNB1 on embryogenesis have each been separately assessed, whereas the effect of its total absence has not. As the ‘traditional’ conditional Ctnnb1 knockout alleles give rise to truncated CTNNB1 fragments, we designed a new knockout allele incapable of CTNNB1 production. Mouse embryos lacking intact maternal/zygotic CTNNB1 from two knockout strains were examined in detail. Preimplantation embryos are formed, yet abnormalities in their size and shape were found throughout pre- and early postimplantation development. In the absence of the zona pellucida, embryos lacking CTNNB1 undergo fission and these separated blastomeres can become small trophoblastic vesicles, which in turn induce decidual reactions. Comparing the severity of this defective adhesion phenotype in embryos bearing the null allele with those carrying the ‘traditional’ knockout allele suggests a hypomorphic effect of the truncated CTNNB1 protein fragment, an important observation with possible impact on previous and future studies.
    Print ISSN: 0950-1991
    Electronic ISSN: 1477-9129
    Topics: Biology
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  • 10
    Publication Date: 2013-02-21
    Description: Inhibition of formyl peptide receptor in high-grade astrocytoma by CHemotaxis Inhibitory Protein of S. aureus British Journal of Cancer 108, 587 (19 February 2013). doi:10.1038/bjc.2012.603 Authors: J C Boer, U M Domanska, H Timmer-Bosscha, I G J Boer, C J C de Haas, J V Joseph, F A E Kruyt, E G E de Vries, W F A den Dunnen, J A G van Strijp & A M E Walenkamp
    Keywords: FPR1CHIPSastrocytomamitochondrial peptidesmigration
    Print ISSN: 0007-0920
    Electronic ISSN: 1532-1827
    Topics: Medicine
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