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  • Springer  (56)
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  • 1
    Electronic Resource
    Electronic Resource
    Effects of ambient ammonia levels on blood ammonia, ammonia excretion and heart and scaphognathite rates of Nephrops norvegicus (1997)
    Springer
    Marine biology 127 (1997), S. 411-418 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During commercial handling of Nephropsnorvegicus (L.) there are a number of situations when the prawns may be exposed to very high ambient ammonia levels. These experiments evaluated the effects of increased levels of ambient total ammonia (TA = NH3 + NH4 +) on␣blood ammonia, ammonia efflux rates and on the cardio-ventilatory performance of N. norvegicus. When prawns were taken from 〈1 to 2000 μmol TA l−1 medium, blood TA concentrations increased rapidly for the first 2 h but tended to drop thereafter. Original blood TA levels were restored 6 h after the prawns were transferred back from seawater containing 2000 to 〈1 μmol TA l−1. Sudden exposure to 500, 1000, 2000 or 4000 μmol TA l−1 medium induced blood TA concentrations to increase respectively to 50, 30, 33 and 36% of external concentrations (normally, internal TA values are much higher than external levels). Immediately after transfer back to seawater with low ammonia concentration ( 〈1 μmol TA l−1), excretion rates were higher than those of control prawns, and the absolute amounts of TA excreted were considerably higher than those calculated to have accumulated in the haemolymph. Heart rate (HR) and scaphognathite rate (SR) were not altered when prawns were subjected to sudden alterations in ambient ammonia ( 〈1 to 2000 to 〈1 μmol TA l−1). When water ammonia concentrations were altered more gradually, both rates increased, but only at 4000 μmol TA l−1. These results show that N. norvegicus is able to remove ammonia from the haemolymph and/or transform ammonia into some other substance when subjected to increased levels of ambient ammonia. Possible mechanisms involved (e.g. active transport across the gills; storage in some other tissue; glutamate synthe sis) are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050028
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  • 2
    Electronic Resource
    Electronic Resource
    Haemolymph constituent levels and ammonia efflux rates of Nephrops norvegicus during emersion (1997)
    Springer
    Marine biology 127 (1997), S. 403-410 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nephropsnorvegicus (L.) were subjected to 8 h of emersion, either between layers of seawater-soaked hessian with periodical (20 min) flushes of seawater (high humidity, HH) or to unprotected emersion (low humidity, LH). Blood ammonia levels rose during emersion in both groups but reached higher levels under LH conditions. Ammonia efflux rates after re-immersion were higher than those of control prawns, and amounts of ammonia excreted at such times were considerably higher than those calculated to have accumulated in the blood during emersion. Possible explanations for such differences are discussed. C aO2 and C vO2 decreased rapidly to ca. 10% normoxia values within 2 h of HH and LH emersion and remained low throughout the remaining emersion time. Emersion-induced tissue hypoxia increased blood concentrations of glucose and lactate. Lactate accumulation was higher during LH emersion, compared with HH emersion. Blood pH dropped ca. 0.40 units but increased again after 2 h of re-immersion. Acidosis was probably related more to respiratory difficulties (CO2 accumulation) than to lactate accumulation, as blood lactate values remained high after 2 h of re-immersion. The ability of N. norvegicus to cope with emersion appears to be little influenced by high humidity conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050027
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  • 3
    Electronic Resource
    Electronic Resource
    Damage anneal of antimony/phosphorus double implants in silicon (1980)
    Springer
    Applied physics 22 (1980), S. 137-143 
    Details
    ISSN: 1432-0630
    Keywords: 61.70.Tm ; 61.80.Jh ; 61.70.Ph
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract A method is presented for avoiding the dislocation generation in (100) silicon implanted with phosphorus doses up to 5×1015 ions/cm2 at 50 keV. The residual defects after the damage anneal are considerably reduced if the phosphorus implant is combined with a low dose, e.g. 1×1014 ions/cm2, antimony implant which produces a deeper surface layer of amorphous silicon. It is essential that the phosphorus ions are implanted shallower than the antimony ions, and come to rest within the amorphous layer. Subsequent thermal annealing proceeds by a solid phase epitaxial regrowth mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00885996
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  • 4
    Electronic Resource
    Electronic Resource
    Transient adsorption of a tri(ethyleneglycol) polyacrylate on a plasmapheresis membrane (1991)
    Springer
    Colloid & polymer science 269 (1991), S. 36-42 
    Details
    ISSN: 1435-1536
    Keywords: Polymer adsorption ; tri(ethyleneglycol) polyacrylate ; plasmapheresis ; membrane
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract We study the adsorption of polyacrylate of tri(ethyleneglycol) in water on a plasmapheresis membrane, whose main constituent is a copolymer of acrylonitrile and methylmethacrylate. The amount of adsorbed polymer has a strong dependence on pH. Adsorbance is high at low pH and very low at high pH, while in the intermediate range the interfacial concentration Γ is not a monotonic function of the solution concentrationC. Viscosimetry andUV adsorbance measurements in solution suggest the existence of plurimolecular structures, aggregates, or micelles. We propose a kinetic model, where these latter objects act as detergents at highC and, therefore, contribute to decreasing the interfacial concentration Γ when increasingC.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00654657
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  • 5
    Electronic Resource
    Electronic Resource
    Visible surface calculation for complex unstructured polygonal scences (1985)
    Springer
    Computing 35 (1985), S. 231-246 
    Details
    ISSN: 1436-5057
    Keywords: 51N20 ; 68-04 ; 68C05 ; 68C25 ; Visible surface algorithms ; computational geometry ; computer graphics ; computational complexity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Das Visible-Surface-Problem besteht darin, die Teilpolygone einer 3-D-Szene aus beliebigen einfachen planaren Polygonen zu bestimmen, die von einem gegebenen Augenpunkt aus sichtbar sind. Der Algorithmus der hier vorgestellt wird, und der für umfangreiche Szenen ausgelegt ist, löst dieses Problem durch implizites Zerlegen bezüglich eines Zellrasters. Die Komplexitätsabschätzung führt zu Aussagen über die günstige Wahl des Gitters und zu der Charakterisierung von Szenenklassen, welche bei praktischen Anwendungen auftreten, und für die der Algorithmus ein lineares Zeit- und Speicherplatzverhalten zeigt.
    Notes: Abstract The visible surface problem is to determine those subpolygons of a 3-D scence of arbitrary simple planar polygons which are visible from a given viewpoint. The algorithm which is presented here, and which is designed for complex scenes solves this problem by an implicit partitioning w.r.t. a raster of cells. The estimation of complexity leads to propositions on the favorable choice of the grid, and to the characterization of classes of scenes, which are relevant for practical applications, and for which the algorithm shows a linear time and space behavior.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02240191
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  • 6
    Electronic Resource
    Electronic Resource
    Zur Theorie der nichtdeterministischen und unvollständigen Automaten (1969)
    Springer
    Computing 4 (1969), S. 56-74 
    Details
    ISSN: 1436-5057
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Summary Non-deterministic incomplete sequential machines (NISM) are generalizations of the well-known deterministic complete sequential machines (DCSM) ofMealy type. The NISM are derived from the DCSM by replacing the next state and output function by a correspondence, that is a generalized multivalued mapping. Therefore the states generate input-output correspondences instead of sequential functions and two states are defined to be equivalent if the two correspondences genrated by the states are equal. Exactly the simply defined sequential correspondences can be generated by states of NISM. If there is aZ-epimorphism of one machine onto another, then these machines are equivalent. To each NISM there exists an equivalent machine with pairwise inequivalent states, i. e. a reduced machine, which is in general not unique up to an isomorphism. But reduced equivalent and so-called “komplettierte” machines are isomorphic. Precisely the “halbkomplettierten” machines allowZ-epimorphisms onto reduced machines. If a finite NISM is given, then an equivalent reduced machine can be obtained by an algorithm similar to but more complicated than in the case of the DCSM. The developed algorithm is demonstrated by an example.
    Notes: Zusammenfassung Nichtdeterministische und unvollständige Automaten (NUA) sind eine Verallgemeinerung der vielfach untersuchten deterministischen und vollständigenMealy-Automaten (DVA). Die NUA erhält man aus den DVA, wenn man die Abbildung für Folgezustand und Ausgabe durch eine Korrespondenz, also eine mehrdeutige Abbildung ersetzt. An die Stelle der bei DVA von Zuständen erzeugten Automatenabbildungen treten dann Korrespondenzen, und zwei Zustände eines NUA heißen demgemäß äquivalent, wenn die in ihnen dargestellten Korrespondenzen gleich sind. Genau die einfach definierbaren Automatenkorrespondenzen sind in Zuständen von NUA darstellbar.Z-epimorph aufeinander abbildbare Automaten sind äquivalent, und zu jedem NUA gibt es einen äquivalenten Automaten mit paarweise inäquivalenten Zuständen, also einen voll reduzierten Automaten, der jedoch im allgemeinen nicht bis auf Isomorphie eindeutig bestimmt ist. Aber voll reduzierte, äquivalente und sogenannte komplettierte Automaten sind stets isomorph und genau die halbkomplettierten NUA lassen einenZ-Epimorphismus auf einen voll reduzierten Automaten zu. Zu endlichen NUA lassen sich algorithmisch äquivalente, voll reduzierte Automaten bestimmen. Der entwickelte Algorithmus wird an einem Beispiel demonstriert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02236542
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  • 7
    Electronic Resource
    Electronic Resource
    Importance of pause between spider courtship vibrations and general problems using synthetic stimuli in behavioural studies (1993)
    Springer
    Journal of comparative physiology 172 (1993), S. 707-714 
    Details
    ISSN: 1432-1351
    Keywords: Vibratory communication ; Spider behaviour ; Playback ; Natural stimulus ; Synthetic stimulus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Effectiveness of natural stimuli (recorded and replayed male vibratory courtship signals) in eliciting a female's vibratory response was compared with that of synthetic stimuli in a plant-dwelling spider (Cupiennius salei). Specifically, the role of interseries (pauses between consecutive male series) was evaluated. Effectiveness was assessed by the number of responding females and the number of responses per female per stimulus. In case of both synthetic and natural stimuli, effectiveness increases with increasing duration of interseries in both measures. Interseries are thus represented in the female's innate releasing mechanism. However, synthetic stimuli are less effective (about 55%) than natural stimuli (set 100%). With decreasing interseries, the number of female responses per unit time sharply increases in case of playback of natural stimuli, but only slightly in case of synthetic stimuli. Since males courting on plants decrease interseries as soon as a female responds, thus facilitating their orientation, the data obtained with natural stimuli much better fit natural male courtship behaviour. This finding brings into question the validity of the synthetic stimulus. In the bioacoustics literature there is neither consensus on the effectiveness of a synthetic stimulus necessary to qualify it for behavioural analysis nor on how to measure effectiveness. We propose three measures : the percentage of responding animals, the action pattern of the response and the number of responses. It may be crucial, particularly when addressing evolutionary questions, to use either natural stimuli or synthetic stimuli (nearly) as effective as natural stimuli to avoid biased sampling of experimental animals and results difficult to interpret in biological terms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195396
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  • 8
    Electronic Resource
    Electronic Resource
    Recent developments in and applications of resonance ionization mass spectrometry (1999)
    Springer
    Fresenius' journal of analytical chemistry 364 (1999), S. 471-477 
    Details
    ISSN: 1432-1130
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Resonance Ionization Mass Spectrometry (RIMS) has nowadays reached the status of a routine method for sensitive and selective ultratrace determination of long-lived radioactive isotopes in environmental, biomedical and technical samples. It provides high isobaric suppression, high to ultra-high isotopic selectivity and good overall efficiency. Experimental detection limits are as low as 106 atoms per sample and permit the fast and sensitive determination of ultratrace amounts of radiotoxic contaminations. Experimental arrangements for the detection of different radiotoxic isotopes, e.g. 236–244Pu, 89,90Sr and 99Tc in environmental samples are described, and the application of RIMS to the ultrarare long-lived radioisotope 41Ca for cosmochemical, radiodating and medical purposes are presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002160051370
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  • 9
    Electronic Resource
    Electronic Resource
    Thermische Denaturierung von Kaltblüter-Enzymproteinen (1960)
    Springer
    Cellular and molecular life sciences 16 (1960), S. 491-492 
    Details
    ISSN: 1420-9071
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The temperature, which leads to 50% reduction of catalytic activity by heat denaturation, has been determined for 8 different enzymes from cod muscle, as being in the range between 30 and 52°C. Therefore, there are no indications of a generally different heat resistance of enzymes from cold-blooded animals as compared with those from warm-blooded animals. The same conclusion is derived from calculations ofQ 10-values, measured between +37 and − 37°C for cathepsin and glycylglycine dipeptidase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02158354
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  • 10
    Electronic Resource
    Electronic Resource
    Isolierung und Eigenschaften von Lipofuscin aus Herzgewebe des Menschen (1962)
    Springer
    Histochemistry and cell biology 3 (1962), S. 17-45 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00737235
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