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  • 1
    ISSN: 1438-3888
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract On Helgoland (North Sea), the imagines ofClunio emerge during two seasonal periods (late spring and summer) from water temperatures of 8°–18 °C. The temperature dependence of the known semilunar eclosion rhythm ofClunio (correlated in nature with the spring tides every 14–15 days) was tested in the laboratory. Between 15° and 23 °C the semilunar eclosion maxima varied by only one day within the artifical 15-day zeitgebercycle, below 15 °C they were delayed up to 8 days at 8 °C. However, the days of pupation were approximately independent of the temperature level. One can conclude the existence of a temperature-independent physiological switch inducing the pupation only within a few days of the semilunar zeitgeber-cycle. Moreover, a semilunar synchronized differentiation of the imaginal discs already starts in the preceding larval instar, indicating an additional physiological switch. A model is suggested in which the semilunar eclosion rhythm and its relatively slight temperature dependence is explained by the action of two physiological switches which are coupled with the endogenous temperature-compensated lunar timing mechanism on the same days of the 15-day zeitgeber-cycle. In the laboratory, the diurnal eclosion and its underlying circadian timing mechanism (correlated on Helgoland with the time of spring low water in the late afternoon) also proved to be temperature independent between 12° and 20 °C. A comparison of field and laboratory data showed very similar results at temperatures around 18 °C (summer swarming period). In contrast, the midges emerged on all days of the semimonthly cycle of springs and neaps during the spring swarming period. This lack of semilunar synchronization may be the consequence of fluctuating temperatures during the larval and pupal development in spring time due to a general rise in the water temperature (4°–8 °C) and to short temperature rises up to 18 °C during exposure of the intertidal habitat at about low tide. Since some higher parts of theClunio habitat suitable for egg deposition are exposed on almost every day of the semimonthly cycle, even such animals that undergo lunar unsynchronized metamorphosis can reproduce within the short imaginal life duration (ca 2 h) if they emerge just about the time of low water. In correspondence with the daily delay in the times of low water by about 50 min, the diurnal eclosion rhythm was in fact modified with the tides during the spring period resulting in shifts of the diurnal eclosion time of up to 12 hours within the semimonthly cycle of springs and neaps.
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  • 2
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Branching ratios for the decay τ→ν+(n pions) withn≧2 are presented. The new data include all possible charge configurations of the pion system and, in particular, final states containing one or several neutral pions. The data are compared with predictions from CVC (even number of pions in final state) and current algebra (odd number of pions). They strongly support the standard coupling of the τ to the weak charged current.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The production of thef 0 in two photon collisions, with the subsequent decayf 0→π+π− has been observed in the CELLO detector at PETRA. Thef 0 peak was found to lie on a dipion continuum and to be shifted downwards in mass by ≃50 MeV/c2. The ππ mass spectrum from 0.8 to 1.5 GeV/c2 was well fitted by the model of Mennessier using only a unitarised Born amplitude and helicity 2f 0 amplitude. The previously observed mass shift and distortion of thef 0 peak are explained by strong interference between the Born andf 0 amplitudes. The only free parameter in the fit of the data to the model is the radiative widthΓ γγ(f 0). It was found that:Γ γγ(f 0)=2.5±0.1±0.5 keV where the first (second) quoted errors are statistical (systematic).
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 121 (1943), S. 377-437 
    ISSN: 1434-601X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Zusammenfassung In einem Medium 1 befinde sich eine Kugelwellenstrahlungsquelle in endlichem Abstand von der Grenzebene gegen ein Medium 2. Es werden dann am elektro-dynamischen Beispiel unter Voraussetzung eines vertikalen Dipols exakte asymptotische Entwicklungen der Potentialfunktion in beiden Medien gegeben, in den Abschnitten 3, 4 für endlichen komplexen, in Abschnitt 5 für reellen Brechungsindex. Die Ergebnisse gelten für Entfernungen, welche groß sind gegen die Wellenlänge, für beliebigen endlichen Abstand der Strahlungsquelle von der Grenzebene und für beliebige Zenitdistanz des Aufpunktes. In dieser Allgemeinheit gelingt die Lösung des Problems mit Hilfe der Weylschen Methode der Transformation der komplexen Ausgangsdoppelintegrale. Durch Spezialisierung werden bisher vorliegende Lösungen wiedergewonnen und dabei durch Berücksichtigung einer von Weyl vernachlässigten Singularität bei komplexer Integration die Weylsche und die hinsichtlich der „Oberflächenwelle“ verbesserte Sommerfeldsche Theorie der Wellenausbreitung, welche im Ansatz übereinstimmen, auch in der Auswertung in völliger Übereinstimmung gefunden. Die Berücksichtigung der erwähnten Singularität liefert ferner mutatis mutandis die von O.v.Schmidt entdeckte elastische „Kopfwelle“.
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 91 (1960), S. 305-306 
    ISSN: 1434-4475
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Archive of applied mechanics 20 (1952), S. 234-246 
    ISSN: 1432-0681
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Zusammenfassung Das aus der Anwendung hochfrequenter Wechselströme auf die Erwärmung von Materialien wachsende allgemeine Problem lautet: Durch Kombination elektromagnetischer und thermischer Felder ist zu einer vorgeschriebenen Zeit ein vorgeschriebener Temperaturverlauf herzustellen. Unter der Annahme des Newtonschen Abkühlungsgesetzes zu beiden Seiten einer unendlich ausgedehnten ebenen Platte der Dicke d wird zunächst bei allgemein gegebener, ebenfalls nur von einer Variablen abhängiger Wärmeproduktion f(z), eine allgemeine Lösung des inhomogenen Wärmeleitungsproblems in solcher Form gegeben, daß daraus die Endtemperaturbedingung abgeleitet werden kann. Als erstes. Beispiel wird aus dieser die Wärmeproduktion berechnet, die nötig wäre, um schon zu vorgegebener endlicher Zeit die Platte auf eine vorgeschriebene konstante Temperatur ϑ o zu bringen, wenn die Anfangstemperatur Null ist und an den Rändern die konstante Temperatur ϑ o herrscht. Die Frage nach dem Aussehen quasistationärer elektromagnetischer Felder in Dielektriken geringen Verlustfaktors, die mit f(z) vereinbar sind, führt auf f(z)=k 1 e k z 1, k Konstante), eine auch für andere wichtige Anwendungen gültige Form der Wärmeproduktion. Für dieses f(z) wird der allgemeine Temperaturverlauf angegeben und die Endbedingung für das Problem ausgewertet, Anfangs- und Randtemperaturen so zu bestimmen, daß sich zu einer vorgeschriebenen endlichen Zeit eine konstante Temperatur in der ganzen Platte einstellt. Es zeigt sich, daß bei diesem Beispiel die gesuchten Temperaturverläufe eindeutig bestimmbar sind und nur bei homogenem Feld (k=0) eine konstante Anfangstemperatur möglich ist.
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  • 7
    ISSN: 1434-4475
    Keywords: Maleimides ; Chemoimmunoconjugates ; Crosslinking reagent
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Bifunctional maleimide compounds are suitable for binding small molecules to carrier proteins in that they bind to the sulfhydryl group of proteins through the double bond of the maleimide group and to molecules of low molecular weight (e.g. anticancer drugs) through a functional groupX. 18 maleimide compounds of the general formula Maleimid-R-X (R=phenylene, benzyl-, methylene-, ethylene, or am-benzoylethylamide group andX=hydroxy-, amino-, hydrazino-, carboxylic acid-, carboxylic anhydride-, carboxylic acid chloride-, carboxylic acid hydrazide-, oxycarbonylchloride-, aldehyde, keto-, orp-toluenesulfonate-group) were synthesized and characterized through1H- and13C-NMR-spectroscopy, elemental analysis, and mass spectrometry.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Applied microbiology and biotechnology 28 (1988), S. 272-275 
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary A microbial amperometric sensor using peptide-induced cells of Bacillus subtilis was developed for the determination of peptides, based on the measurement of change of current (acceleration of respiration). The sensor system showed a low sensitivity for amino acids and glucose, but a high sensitivity for peptides, e.g. angiotensin and gonadotropin-releasing hormone. The microbial peptide sensor could also be used for the determination of proteolytic activities by measurement of the products of protein splitting.
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Electrical engineering 77 (1994), S. 213-219 
    ISSN: 1432-0487
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Description / Table of Contents: Contents Growing concern with environmental pollution encourages renewed investigations in the field of electrically driven vehicles. The most significant drawback of electrical drive systems as applied to autonomous vehicles is their need for a continuous electrical power supply, mostly provided by electrochemical storage batteries. However, due to physical limitations their power and energy capacity is poor compared to liquid fuel. An alternative can be seen in the use of an on-board power supply, with a generator driven by a thermal prime mover. In this case the battery serves only as short-time energy buffer with reduced capacity, weight and cost, whereas the mean electrical power is directly fed from the generator to the electrical drive of the vehicle. In this investigation the use of a high-speed generator, that might be directly coupled to a gas turbine, is proposed to reduce volume and weight of the on-board power supply. This paper deals only with the electromechanical part of the power supply. Experimental results from a generator system rated 10 kW at 36 000 rpm are discussed.
    Notes: Übersicht Wegen zunehmender Umweltbelastungen gibt es wieder verstärkte Entwicklungsanstrengungen zugunsten elektrisch angetriebener Fahrzeuge. Der wesentliche Nachteil autonomer elektrisch angetriebener Fahrzeuge besteht nach wie vor in deren Abhängigkeit von einer kontinuierlichen elektrischen Energiequelle, die in den meisten Fällen durch eine elektrochemische Speicherbatterie bereitgestellt wird. Aufgrund physikalischer Beschränkungen bleibt deren Leistungsdichte und Kapazität jedoch weit hinter der von flüssigen Kraftstoffen zurück. Eine mögliche Alternative besteht in der Verwendung einer Bordstromversorgung, mit einem Generator der durch eine thermische Kraftmaschine angetrieben wird. In diesem Fall dient die Batterie nur als Kurzzeitspeicher, was deren Kosten, Gewicht und Preis wesentlich reduziert. Der Mittelwert der elektrischen Leistung kann direkt vom Generator zum elektrischen Fahrantrieb geführt werden. Um Gewicht und Volumen der Bordstromversorgung zu reduzieren, wird im folgenden die Verwendung eines schnellaufenden Generators, der direkt an eine Gasturbine gekoppelt werden könnte, vorgeschlagen. Der Aufsatz befaßt sich ausschließlich mit dem elektromechanischen Teil der Bordstromversorgung. Experimentelle Ergebnisse mit einem Generatorsystem im Leistungsbereich von 10 kW bei 36 000 min−1 werden vorgestellt.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Oecologia 67 (1985), S. 154-156 
    ISSN: 1432-1939
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Breeding experiments with a temperate zone population of the marine insect Clunio marinus (stock Helgoland-North Sea from 54° N) demonstrated an onset of larval diapause under combined short day and low temperature conditions only (examined LD 8:16 with 7 or 10°C resp.). Long photoperiods (LD 16:8) at 7–10° C or higher temperatures in shorter photoperiods completely prevented any dormancy response. The diapausing larvae were still locomotory active and fed in their benthic environment; their metamorphosis, however, stopped during a specific stage of the early imaginal disc formation in the last instar. In the experiments, the diapause was maintained up to 5.5 months and longer. In nature, the termination may be mainly controlled by temperature rises during low tide and fine weather under long day conditions, at Helgoland generally in late April or early May. The dormancy response can be classified as a larval oligopause (sensu H.J. Müller) of a potentially multivoltine species. It is supposed that this kind of diapause control is more widely distributed in aquatic chironomids.
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