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  • Springer  (687)
  • Institute of Physics  (149)
  • Public Library of Science  (92)
  • Oxford University Press  (86)
  • Frontiers Media  (38)
  • 1
    Electronic Resource
    Electronic Resource
    Ultramikrobestimmung von Phosphat auf katalytischer Grundlage mit Hilfe der Simultankomparationsmethode (1965)
    Springer
    Microchimica acta 53 (1965), S. 1014-1024 
    Details
    ISSN: 1436-5073
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary The ultramicro determination of phosphate ion was conducted on the basis of its catalytic effect in the molybdic acid reduction, with the aid of a new colorimetric procedure. The phosphate-molybdic acid-ascorbic acid system was studied under conditions that correspond best to the kinetic (catalytic) character of the reaction. TheBognár simultaneous comparison method, that is suitable for the quantitative evaluation of kinetic systems, was employed. A method for the determination of phosphate in a concentration range from 0.1–10μg PO4 3−/5 ml is described. The relative error of the determination lies within ± 6.0%. Statements are made regarding the influence of foreign ions.
    Abstract: Résumé On a réalisé suivant un nouveau procédé colorimétrique l'ultramicrodosage de l'ion phosphate en mettant à profit son effet catalytique sur la réduction de l'acide molybdique. On a étudié le système phosphate-acide molybdiqueacide ascorbique dans des conditions correspondant le mieux au caractère cinétique (catalytique) de la réaction. On a utilisé la méthode de comparaison simultanée deBognár, qui convient à l'utilisation quantitative du système cinétique. On décrit un procédé de dosage des phosphates dans le domaine de concentration de 0,1 à 10μg PO4 3−/5 ml. L'erreur relative du dosage se situe à l'intérieur de ± 6,0%. On donne des indications sur l'influence des ions gênants.
    Notes: Zusammenfassung Die Ultramikrobestimmung des Phosphations wurde auf der Grundlage seines katalytischen Effektes bei der Molybdänsäurereduktion mit Hilfe eines neuen kolorimetrischen Verfahrens durchgeführt. Das Phosphat-Molybdänsäure-Ascorbinsäure-System wurde unter Bedingungen, die dem kinetischen (katalytischen) Charakter der Reaktion am besten entsprechen, untersucht. Die SimultankomparationsmethodeBognárs, die zur quantitativen Auswertung kinetischer Systeme geeignet ist, wurde verwendet. Ein Verfahren zur Bestimmung von Phosphat in einem Konzentrationsbereich von 0,1 bis 10μg PO4 3−/5 ml wurde beschrieben. Der relative Fehler der Bestimmung liegt innerhalb ± 6,0%. Über den Einfluß von Fremdionen werden Angaben gemacht.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01219290
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  • 2
    Electronic Resource
    Electronic Resource
    Almost tight bounds forɛ-Nets (1992)
    Springer
    Discrete & computational geometry 7 (1992), S. 163-173 
    Details
    ISSN: 1432-0444
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract Given any natural numberd, 0〈ɛ〈1, letf d (ɛ) denote the smallest integerf such that every range space of Vapnik-Chervonenkis dimensiond has anɛ-net of size at mostf. We solve a problem of Haussler and Welzl by showing that ifd≥2, then $$d - 2 + \frac{2}{{d + 2}} \leqslant \mathop {\lim }\limits_{\varepsilon \to 0} \frac{{f_d (\varepsilon )}}{{(1/\varepsilon )\log (1/\varepsilon )}} \leqslant d.$$ Further, we prove thatf 1(ɛ)=max(2, ⌌ 1/ɛ ⌍−1), and similar bounds are established for some special classes of range spaces of Vapnik-Chervonenkis dimension three.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02187833
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  • 3
    Electronic Resource
    Electronic Resource
    Conductance noise spectrum of mesoscopic systems (1990)
    Springer
    The European physical journal 81 (1990), S. 299-303 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We investigate the shape as well as the size- and temperature-dependence of the conductance noise spectrum of a small system containing electrons and both fixed and mobile scatterers. If the number of mobile scatterers within a phase-coherent region is sufficiently large, the temporal variation of the conductance can be viewed as a random walk process limited by the universal conductance fluctuations, resulting in a practically Lorentzian power spectrum. We discuss the conditions under which the noise spectrum of a system consisting of many phase-coherent regions is either Lorentzian or 1/f-like. The temperature-dependence of the power spectrum is determined by the hopping mechanism and the variation of the phase breaking length. As a function of temperature the spectrum satisfies power law scaling relations with exponents depending on the dimension and the temperature range; the spectral intensity can both increase and decrease with decreasing temperature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01309362
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  • 4
    Electronic Resource
    Electronic Resource
    Effect of Inorganic and Organic Tin Compounds on ACh- and Voltage-Activated Na Currents (2000)
    Springer
    Cellular and molecular neurobiology 20 (2000), S. 591-604 
    Details
    ISSN: 1573-6830
    Keywords: tin ; acetylcholine ; Lymnaea stagnalis L. ; membrane currents ; mollusks ; Na channel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. Inorganic tin and organotin compounds, occurring in aquatic ecosystems, are toxic and can cause behavioral abnormalities in living organisms. To determine the possible neuronal basis of these actions, the effects of both forms of Sn were studied on identified neurones of the mollusk, Lymnaea stagnalis L. 2. SnCl2 caused a dose-dependent decrease in the acetylcholine (Ach)-induced inward current. The effective threshold concentration, measured by a two microelectrode voltage clamp technique, was 0.1 μM, and the maximal effect occurred at 5 μM SnCl2. The depression of the inward current was greater after a 10 min preapplication (20%) than after 3 min treatment (7%). 3. The next series of experiments compared the actions of inorganic or organic tin compounds. In whole cell clamp experiments both (CH3)2SnCl2 and (CH3)3SnCl, like inorganic Sn, decreased the amplitude of Ach-induced current. Increasing the duration of the preapplication time resulted in an increase in the effect, but the action was not reversible. SnCl2 treatment caused a concentration-dependent alteration (initial potentiation followed by depression) of the amplitude of I Na(V) over the whole voltage range and slightly shifted the I–V curves to the left. In contrast, trimethyl tin decreased the amplitude of I Na(V) only at high concentration (100 μM). The activation time course of I Na was increased (τ = 0.43 ms in control and 0.55 ms in Sn), but Sn did not alter the inactivation parameters (τ = 3.43 and 3.41 ms). 4. These results support earlier findings that agonist- and voltage-activated channels are direct targets of toxic metals. We conclude that tin in both inorganic and organic forms acts at neuronal membranes to modulate synaptic transmission through direct actions on agonist-activated ion channels, and suggest that these actions may be the basis of the altered behavior of animals in tin-polluted environments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007016012520
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  • 5
    Electronic Resource
    Electronic Resource
    Palladium as a Catalyst in a Polycondensed Matrix, Part 1 (2000)
    Springer
    Reaction kinetics and catalysis letters 71 (2000), S. 153-158 
    Details
    ISSN: 1588-2837
    Keywords: Palladium adducts in organic matrix ; palladium polycondensation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Adducts of palladium and organic amines were polycondensed. The catalysts formed were studied in liquid-phase hydrogenations of simple organic molecules. Their activities and specific selectivities were compared with these of a palladium/carbon catalyst.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010363022434
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  • 6
    Electronic Resource
    Electronic Resource
    The study of chemical reactions, absorption and extraction, using apparatuses with serpentine pie for pelliclizing-bubbling, XIV. Hydroperoxidation of 1,3-diisopropylbenzene with oxygen (1999)
    Springer
    Reaction kinetics and catalysis letters 68 (1999), S. 213-219 
    Details
    ISSN: 1588-2837
    Keywords: 1,3-diisopropylbenzene ; hydroperoxidation ; apparatus of Vodnártype ; disodium adipate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Experimental results obtained by thermal hydroperoxidation of 1,3-diisopropylbenzene in the temperature region of 102–105°C, using a Vodnár-1 type apparatus with discontinuous operation are presented. Based on the results, the activation energy (E=48.5±2 kJ/mol), enthalpy (ΔH+=47±2 kJ/mol), entropy (ΔS+) and the activation free enthalpy (ΔG+) were calculated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02475504
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  • 7
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    Ablation of TNAP function compromises myelination and synaptogenesis in the mouse brain (2012)
    Springer
    Details
    Publication Date: 2012-06-14
    Print ISSN: 0302-766X
    Electronic ISSN: 1432-0878
    Topics: Biology , Medicine
    Published by Springer
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  • 8
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    Modeling social dynamics in a collaborative environment (2014)
    Springer
    Details
    Publication Date: 2014-11-14
    Description: Wikipedia is a prime example of today’s value production in a collaborative environment. Using this example, we model the emergence, persistence and resolution of severe conflicts during collaboration by coupling opinion formation with article editing in a bounded confidence dynamics. The complex social behavior involved in editing articles is implemented as a minimal model with two basic elements; (i) individuals interact directly to share information and convince each other, and (ii) they edit a common medium to establish their own opinions. Opinions of the editors and that represented by the article are characterised by a scalar variable. When the pool of editors is fixed, three regimes can be distinguished: (a) a stable mainstream article opinion is continuously contested by editors with extremist views and there is slow convergence towards consensus, (b) the article oscillates between editors with extremist views, reaching consensus relatively fast at one of the extremes, and (c) the extremist editors are converted very fast to the mainstream opinion and the article has an erratic evolution. When editors are renewed with a certain rate, a dynamical transition occurs between different kinds of edit wars, which qualitatively reflect the dynamics of conflicts as observed in real Wikipedia data.
    Electronic ISSN: 2193-1127
    Topics: Computer Science
    Published by Springer
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  • 9
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    Regulation of plankton by omnivore cyprinids in a shallow lake in the Kis–Balaton Reservoir System (2003)
    Springer
    Details
    Publication Date: 2003-09-01
    Print ISSN: 0018-8158
    Electronic ISSN: 1573-5117
    Topics: Biology
    Published by Springer
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  • 10
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    Ultramikrobestimmung von Phosphat auf katalytischer Grundlage mit Hilfe der Simultankomparationsmethode (1965)
    Springer
    Details
    Publication Date: 1965-09-01
    Print ISSN: 0026-3672
    Electronic ISSN: 1436-5073
    Topics: Chemistry and Pharmacology
    Published by Springer
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