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  • 1
    Electronic Resource
    Electronic Resource
    The temporal effects of Dufour's gland secretion in host discrimination by Nemeritis canescens (1985)
    Springer
    Entomologia experimentalis et applicata 38 (1985), S. 215-220 
    Details
    ISSN: 1570-7458
    Keywords: Nemeritis canescens ; Hymenoptera ; Ichneumonidae ; Ephestia kuehniella ; Dufour's gland ; marker pheromone ; discrimination ; superparasitism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Des expériences sur le comportement de N. canescens ont montré que les sécrétions de la glande de Dufour sont utilisées comme phéromone de marquage pouvant affecter le comportement des autres hyménoptères face aux chenilles contaminées. Ce maqueur externe est produit à partir des sécrétions de la glande de Dufour, il a un effet dissuasif qui dure environ 32 heures après son émission. La séquence des actes comportementaux de Nemeritis montre un accroissement significatif de réactions de ‘fuite’ et d'‘évitement’ face à des chenilles d'Ephestia traitées superficiellement avec du contenu des glandes de Dufour. Cet article prouve pour la première fois que Nemeritis réagit aussi bien à des marqueurs externes qu'internes. Un comportement analogue vis à vis de papier filtre imprégné du contenu des glandes de Dufour et de son constituant hénéicosane constitue une preuve que le contenu de la glande influe sur le comportement de l'hymenoptère et ainsi lui évite de superparasiter ses hôtes.
    Notes: Abstract Behavioural experiments with Nemeritis canescens Grav. have demonstrated that the secretions from its Dufour's gland are used as a marker pheromone which can affect the behaviour of other wasps towards host caterpillars bearing it. The external marker is produced within the complex of secretions from the Dufour's gland and has oviposition deterrent effect which lasts approximately 32 h after deposition. The sequence of behaviour patterns shown by individual Nemeritis is described and shows a significant increase in ‘escape’ and ‘avoidance’ reactions towards Ephestia caterpillars treated topically with the Dufour's gland contents. This paper presents evidence for the first time to indicate that Nemeritis reacts to an external marker as well as to an internal one. Similar behaviour towards filter paper treated topically with contents of whole Dufour's gland and its component heneicosane contribute evidence for the conclusion that the gland contents influence the wasp's behaviour and hence its avoidance of superparasitism of its host.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00295253
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    A quantitative method for thein vitro study of sounds produced by prosthetic aortic heart valves Part II: an experimental, comparative study of the sounds produced by a normal and simulated-abnormal Starr-Edwards series 2400 aortic prosthesis (1984)
    Springer
    Medical & biological engineering & computing 22 (1984), S. 40-47 
    Details
    ISSN: 1741-0444
    Keywords: Fast Fourier transform ; In vitro comparison ; Sound ; Starr-Edwards 2400 prosthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract A comparative study was made of the sounds produced by a normal Starr-Edwards 2400 aortic valve prosthesis with those produced by the same valve but having a simulated overgrowth at the apex of the struts. Comparisons were made over the entire cardiac cycle for time and amplitude, power-density spectra, power-distribution spectra, power-distribution surfaces associated with individual valves, and three-dimensional power-distribution-difference surface. Power-density spectra were compared for portions of the cycle corresponding to the opening, systolic, and closing sounds of the valve. Physical parameters of an acoustical model were estimated from the power-density spectra. The results showed that each comparison gave information pertinent to the simulated malfunction. Opening. systolic and closing sounds, respectively, were different for each valve. The opening sound of the abnormal valve displayed a much lower frequency. Systolic sounds for the two valves were similar in frequency, but the normal valve produced more total power for this sound. The closing sound of the abnormal valve occurred later than that of the normal valve. These differences were more clearly seen when viewed in the frequency domain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02443744
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    A quantitative method for thein vitro study of sounds produced by prosthetic aortic heart valves Part III: an experimental comparative study of the sounds produced by normal and simulated-abnormal Smeloff aortic prostheses (1984)
    Springer
    Medical & biological engineering & computing 22 (1984), S. 48-54 
    Details
    ISSN: 1741-0444
    Keywords: Fast Fourier transform ; In vitro comparison ; Smeloff prosthesis ; Sound
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Anin vitro study was made of the sounds produced by a normal, Smeloffaortic-valve prosthesis and compared for the entire cardiac cycle with the same valve having a simulated overgrowth on the upstream struts. Time and amplitude information, power-density spectra, power-distribution functions, and three-dimensional power-frequency-time surfaces were compared. Power-density spectra and power-distribution functions were compared in more detail for those portions of the cycle corresponding to the opening, systolic, and closing sounds of the valve. Parameters for the acoustical model were estimated from these power-density spectra. All results were then compared and discussed in terms of the physical changes in the valve. Each comparison gave useful information about the simulated malfunction. Opening, systolic, and closing sounds were different for each case. More power was displayed in the opening sound of the abnormal valve and the systolic sound was early. The closing sound of the abnormal valve had a lower frequency content, and a diastolic sound was observed only for the abnormal valve. Use of the frequency domain gave additional understanding of differences in performance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02443745
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
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