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  • Numerical Methods and Modeling  (4)
  • Adélie Penguin  (1)
  • Cell death  (1)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Oecologia 83 (1990), S. 420-426 
    ISSN: 1432-1939
    Schlagwort(e): Adélie Penguin ; energetics ; Microclimate ; Reproduction ; Thermoregulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We measured meteorological conditions and estimated the energy costs of thermoregulation for young and adult Adélie Penguins (Pygoscelis adeliae) at a breeding colony near the Antarctic Peninsula. Air temperatures averaged 〈 5°C and strong winds were frequent. Operative temperatures (Te) for adults ranged from −8 to 28°C, averaging 5–6°C, for the period from courtship to fledging of chicks. The average energy cost of thermoregulation (Cth) for adult penguins was equivalent to 10–16% of basal metabolism. Cth comprised about 15% of the estimated daily energy budget (DEB) of incubating adults, but only about 1% of the DEB of adults feeding chicks. The Te's for chicks older than 14 days ranged from 0 to 31°C, averaging 8.0 C. The Cth for downy chicks ranged from about 31% of minimal metabolic rate (MMR) in 1 kg chicks to about 10% of MMR in 3 kg chicks. Between initial thermal independence (age 12–14 days) and the cessation of parental feeding (age 35–40 days), chicks use about 10–11% of assimilated energy for thermoregulation. Cth is equivalent to about 17% of the MMR of fledglings during their 2–3 week fast. We observed no indication of thermal stress (i.e., conditions in which birds cannot maintain stable Tb) in adults and no indication of cold stress in any age class. However, on clear, calm days when air temperature exceeds 7–10°C for several hours, downy chicks are vulnerable to lethal hyperthermia.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Development genes and evolution 183 (1977), S. 41-59 
    ISSN: 1432-041X
    Schlagwort(e): Imaginal discs ; Pattern formation ; Cell death ; Duplication
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary We describe the range of phenotypes caused by cell death when larvae of the heat-sensitive cell-lethal mutant,l(1)ts726 ofDrosophila, are subjected to heat treatment at different stages of development. When the treatment extends into the pupal period, certain bristles fail to develop but the disc derivatives are otherwise normal. Earlier treatments cause the replacement of sets of leg and eye-antennal markers by mirror image duplications of neighbouring sets. The results are compared in detail with those expected under a gradient model proposed earlier to account for the phenotype. It is found that although the results for the second leg are in excellent agreement with the predictions of the model, a more elaborate hypothesis is necessary to account for the eye-antennal disc data. Abnormal head patterns fall into several distinct categories, any one of which could be explained by postulating the existence of a gradient, if other categories did not also occur. The markers affected in each case belong to overlapping sets, and each category of pattern can be induced by heat treatments administered throughout the temperature-sensitive period. The statistical distribution of the data is such that only one category of pattern would be detected in a small scale experiment. The possible implications relative to pattern formation in normal development are discussed.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 27 (1998), S. 1-11 
    ISSN: 0271-2091
    Schlagwort(e): Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Maschinenbau
    Notizen: No Abstract
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 28 (1998), S. 1325-1353 
    ISSN: 0271-2091
    Schlagwort(e): finite elements ; compressible flow ; artificial viscosity ; Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Maschinenbau
    Notizen: The performance of different shock capturing viscosities has been examined using our general fluid mechanics algorithm. Four different schemes have been tested, both for viscous and inviscid compressible flow problems. Results show that the methods based on the second gradient of pressure give better performance in all situations. For instance, the method constructed from the nodal pressure values and consistent and lumped mass matrices is an excellent choice for inviscid problems. The method based on L2 projection is better than any other method in viscous flow computations. The residual based anisotropic method gives excellent performance in the supersonic range and gives better results in the hypersonic regime if a small amount of residual smoothing is used. © 1998 John Wiley & Sons, Ltd.
    Zusätzliches Material: 23 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 27 (1998), S. 57-80 
    ISSN: 0271-2091
    Schlagwort(e): high speed flow ; shock modelling ; numerical method ; computational fluid dynamics ; Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Maschinenbau
    Notizen: In this paper we compare the performance of a new general algorithm developed recently in application to problems of high Mach number flows with the performance of specialised algorithms applicable only to such flows. It appears that the results for most examples compare well, the biggest difference occurring in that of high Mach number compression corner. © 1998 John Wiley & Sons, Ltd.
    Zusätzliches Material: 10 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 27 (1998), S. 41-55 
    ISSN: 0271-2091
    Schlagwort(e): unstructured mesh ; compressible flow ; transient flow ; mesh adaptation ; moving boundaries ; Delaunay triangulation ; Engineering ; Numerical Methods and Modeling
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Maschinenbau
    Notizen: The solution of high-speed transient inviscid compressible flow problems in three dimensions is considered. Discretization of the spatial domain is accomplished by the use of tetrahedral elements generated by Delaunay triangulation with automatic point creation. Methods of adapting the mesh to allow for boundary movement are considered and a strategy for ensuring boundary recovery is proposed. An explicit multistage time-stepping algorithm is employed to advance the flow solution. A number of examples are included to illustrate the numerical performance of the proposed procedures. © 1998 John Wiley & Sons, Ltd.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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