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  • Articles: DFG German National Licenses  (3)
  • Aerobic power  (1)
  • Neoseiulus barkeri (Amblyseius mckenziei)  (1)
  • Potentiometrische Titration  (1)
  • 1
    Electronic Resource
    Electronic Resource
    How larvae of Thrips tabaci reduce the attack success of phytoseiid predators (1989)
    Springer
    Entomologia experimentalis et applicata 50 (1989), S. 47-51 
    Details
    ISSN: 1570-7458
    Keywords: Neoseiulus barkeri (Amblyseius mckenziei) ; Amblyseius cucumeris ; Thrips tabaci ; biological control ; attack success ; prey defence ; predation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Neoseiulus barkeri (= Amblyseius mckenziei) und Amblyseius cucumeris (Acari: Phytoseiidae) werden zur Bekämpfung von Thrips tabaci (Insecta: Thripidae) in Gewächshauskulturen eingesetzt. Sowohl der Ernährungszustand der räuberischen Milben als auch die Grösse der Thripslarven haben Einfluss auf das Ausmass der Beutenahme. Die Prädatoren sind erfolgreicher, wenn sie eine Zeitlang ohne Nahrung gehalten wurden. Beim Zusammentreffen mit einer ausgehungerten Raubmilbe besteht für Thripslarven des zweiten Stadiums ein geringeres Risiko erbeutet und gefressen zu werden als für Larven des ersten Stadiums. T. tabaci Larven mindern den Angriffserfolg der Prädatoren durch kräftiges Hin- und Herschlagen des Abdomens und durch Abgabe eines Tropfens Rektalflüssigkeit. Wird dieses Abwehrverhalten der Larven durch Anaästhesie mit CO2 verhindert, erhöht sich der Angriffserfolg der Prädatoren. Anästhesie nivelliert jedoch nicht das für beide Larvenstadien unterschiedlich hohe Risiko erbeutet zu werden. Mögliche Ursachen für diesen Unterschied werden diskutiert. Die Verfügbarkeit geeigneter Beutetiere hängt ab von der zeitlichen Entwicklung der Altersstruktur ihrer Population. Das Angebot an wirklich geeigneten Beutetieren kan also unter Umständen geringer sein, als dies die Gesamtthripsdichte zunächst vermuten lässt. Ist das der Fall, dürften alternative Nahrungsquellen für die Ernährung der Prädatorenpopulation wichtig sein.
    Notes: Abstract Neoseiulus barkeri (= Amblyseius mckenziei) and Amblyseius cucumeris (Acari:Phytoseiidae) are used as control agents of Thrips tabaci (Insecta:Thripidae) in greenhouse crops. Their success in capturing prey larval stages is related to both the feeding state of the predators and to the size of the larvae. When starved, predators are more successful in seizing larvae. Upon contact with a starved predator second stage prey larvae incur a lower death risk than first stage larvae. The larvae of T. tabaci reduce the attack success of their predators by jerking the abdomen and by producing a drop of rectal fluid. When this defensive behaviour is prevented by anaesthetising the larvae with CO2, predator attack success increases. Anaesthesia does not, however, level out the difference in death risk of the two larval stages. Conceivable causes for this discrepancy are discussed. Availability of suitable prey is dependent on the dynamics of the age structure of the prey population and, hence, may be lower than total thrips density suggests. If so, alternative food sources may be important to maintain the predator population.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00190128
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Supramaximal cycle tests do not detect seasonal progression in performance in groups of elite speed skaters (1992)
    Springer
    European journal of applied physiology 64 (1992), S. 292-297 
    Details
    ISSN: 1439-6327
    Keywords: Aerobic power ; Anaerobic power ; Training
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Seven female and eight male elite junior skaters performed cycle ergometer tests at four different times during the 1987/1988 season. The tests consisted of a Wingate-type 30-s sprint test and a 2.5-min supramaximal test. The subjects were tested in February, May and September 1987 and in January 1988. Maximal oxygen consumption was measured during the 2.5-min test. With the exception of the maximal oxygen consumption of the women in May which was about 6% lower than in the other three tests, no seasonal changes in the test results could be observed —this, in spite of a distinct increase in training volume (from 10 to more than 20 h · week−1) and training intensity in the course of the season. When the test data were compared to those of elite senior skaters, it appeared that the junior skaters showed the same values for mean power output during the sprint test [14.2 (SD 0.4) W · kg−1 for the men and 12.6 (SD 0.5) W · kg−1 for the women] and maximal oxygen consumption [63.1 (SD 2.8) ml· kg−1 · min−1 for the men and 55.3 (SD 3.5 ml · kg−1 · min−1 for the women, respectively] as found for senior skaters. It seemed, therefore, that the effects of training in these skaters had already levelled off in the period before they participated in this investigation. In contrast to previous studies, no relationship could be shown between the test results and skating performance. This was most likely due to the homogenous character of the groups (mean standard deviations in power and oxygen consumption were only 5%). It was concluded that the present cycle tests used to measure aerobic and anaerobic power were obviously not of use in evaluating seasonal changes in performance in these groups of highly trained athletes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00636214
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    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Accurate and precise determination of 2–25 mg amounts of uranium by means of a special automatic potentiometric titration (1978)
    Springer
    Fresenius' Zeitschrift für analytische Chemie 289 (1978), S. 102-105 
    Details
    ISSN: 1618-2650
    Keywords: Best. von Uran ; Potentiometrische Titration ; 2–25 mg, automatisch
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Summary A precise and accurate potentiometric titration of 2–25 mg of uranium is described. The uranium is reduced to U(IV) according to the method of Eberle et al. [3], and titrated with 0.05 N potassium dichromate, using a platinum indicator electrode. During the sample preparation the walls of the titration vessel are cleaned by centrifugation. To avoid overshoot of the set point a special differentiator is described, that interrupts the titration until equilibrium is reached. The precision of the method is 0.02%, the accuracy is better than 0.04% rel. Each titration takes 5 min.
    Notes: Zusammenfassung Das Uran wird nach Eberle et al. [3] zu U(IV) reduziert und mit 0.05 N Kaliumdichromatlösungtitriert, wobeider Endpunktmittels einer Platinelektrode indiziert wird. Während der Probevorbereitung wird das Titrationsgefäß zentrifugiert, um die Wände zu reinigen. Eine Überschreitung des vorgewählten Endpunktes wird verhütet, indem ein spezieller Differentiator die Titration unterbricht, bis sich das Gleichgewicht eingestellt hat. Die Reproduzierbarkeit des Verfahrens beträgt 0,02% relativ, die Genauigkeit ist besser als 0,04% relativ. Die Zeitaufwand beträgt 5 min pro Titration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00443954
    Library Location Call Number Volume/Issue/Year Availability
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    Paper (German National Licenses)
    Fulltext
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