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  • FLUID MECHANICS AND HEAT TRANSFER  (4)
  • STRUCTURAL MECHANICS  (2)
  • Trimorphic incompatibility  (2)
  • Behavior  (1)
  • Chemistry  (1)
  • Heterostyly  (1)
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  • 1
    Digitale Medien
    Digitale Medien
    Trimorphic incompatibility in Eichhornia azurea (Pontederiaceae) (2000)
    Springer
    Sexual plant reproduction 12 (2000), S. 203-208 
    Details
    ISSN: 1432-2145
    Schlagwort(e): Key words Tristyly ; Trimorphic incompatibility ; Pollen trimorphism ; Partial incompatibility ; Clonal aquatic plant
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract  Eichhornia azurea (Pontederiaceae) is a mat-forming, clonal aquatic that inhabits lakes, marshes and river systems in many parts of the Neotropics. The species is tristylous with long-, mid-, and short-styled morphs commonly represented in natural populations. To investigate whether E. azurea possesses a trimorphic incompatibility system typical of tristylous species, we conducted a controlled pollination experiment on 15 clones representing the three style morphs from a natural population near Rosario, Argentina. Comparisons of fruit and seed set following self-, illegitimate, and legitimate pollinations clearly demonstrated the presence of trimorphic incompatibility in E. azurea. Self- and illegitimate pollinations produced significantly less fruit and seed than legitimate pollinations in all three style morphs. Pollen from the two anther levels within a flower exhibited contrasting compatibility relations in self-pollinations. In common with several other tristylous species in Pontederiaceae, the expression of self-incompatibility was weakest in the mid-styled morph and strongest in the short-styled morph. We discuss the ecological and evolutionary significance of the partial expression of trimorphic incompatibility in E. azurea.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s004970050001
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Pollinator foraging behavior and pollen collection on the floral morphs of tristylous Pontederia cordata L. (1987)
    Springer
    Oecologia 74 (1987), S. 347-351 
    Details
    ISSN: 1432-1939
    Schlagwort(e): Pontederia cordata ; Bombus ; Tristyly ; Pollination ; Behavior
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The foraging behavior of the pollinators of tristylous Pontederia cordata was studied to determine if differences in floral morphology would lead to preferential visitation of the floral morphs. Although nectar production is not different in the three floral morphs, differences in the production and size of pollen grains produced by the three anther levels results in the morphs offering variable amounts of resources to pollen-collecting insects. Bumblebees (Bombus spp.) and the solitary bee Melissodes apicata used P. cordata primarily as a nectar source and therefore did not seem to exhibit any morph preference. In contrast, honeybees visited flowers mainly for pollen and preferred to forage on long-level anthers of the short-and mid-styled morphs. An analysis of the composition of corbicular pollen loads indicated that, relative to the frequency of production in the population: 1) honeybees collected an excess of pollen from long-level anthers; 2) bumblebees collected the three types of pollen without any apparent preference; and 3) M. apicata preferentially collected pollen from the short-level anthers — presumably because their proboscides are modified by the presence of tiny hairs. The results suggest that P. cordata in Ontario is serviced by a diverse, unspecialized pollinator fauna which is not co-adapted to the tristylous floral polymorphism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00378928
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Variation in expression of trimorphic incompatibility in Pontederia cordata L. (Pontederiaceae) (1985)
    Springer
    Theoretical and applied genetics 70 (1985), S. 355-362 
    Details
    ISSN: 1432-2242
    Schlagwort(e): Trimorphic incompatibility ; Pontederia cordata L.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Pontederia cordata L. (Pontederiaceae), a perennial diploid, possesses the rare genetic polymorphism tristyly. A controlled pollination programme was conducted over a three year period, under glasshouse conditions, on 36 clones of P. cordata var. cordata to examine the nature of the self-incompatibility system. The three major findings of the pollination study were: (1) the three floral morphs display different levels of self-incompatibility, (2) pollen from the two anther levels within a flower exhibits different compatibility behaviour in self-pollinations, (3) considerable individual genetic variation in the expression of self-incompatibility is evident among clones within floral morphs. Similar results were also obtained from a smaller study on 15 clones of P. cordata var. lancifolia conducted over a 6 month period. In common with other Pontederia species the mid-styled morph (M) of P. cordata produces large amounts of seed when self-pollinated with pollen from long-level anthers. A developmental model is proposed to explain the high level of self-compatibility of the M morph in Pontederia species. Self-pollination of segregating progenies from M and S morphs of known incompatibility status demonstrated that the expression of incompatibility is closely associated with style length. It is suggested that overall differences in incompatibility behaviour among the floral morphs may be due to the pleiotropic effects of major genes controlling sub-characters of the tristylous syndrome, rather than linked modifier genes. However, the variable expression of trimorphic incompatibility within floral morphs suggests that this variation may be polygenic in origin.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00273739
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  • 4
    Digitale Medien
    Digitale Medien
    Attachment of gelatin films to tissue using argon beam coagulator (1998)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Biomedical Materials Research 43 (1998), S. 89-98 
    Details
    ISSN: 0021-9304
    Schlagwort(e): gelatin ; films ; tissue ; bonding ; argon beam ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin , Technik allgemein
    Notizen: Cross-linked gelatin films were bonded to heart muscle and to lung pleura and parenchyma using the electrical discharge of an argon beam radiofrequency coagulator. The bonds were stable in warm saline buffer for minutes to hours. Bonding was thought to partly occur through a mechanical interlock of film and tissue elements. The interdigitation of tissue and film arose during exposure to the argon beam, which denatured protein constituents of both, and created a fluidized state that rapidly coalesced. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 43: 89-98, 1998
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Heterostyly in the Lamiaceae: The case ofSalvia brandegeei (2000)
    Springer
    Plant systematics and evolution 223 (2000), S. 211-219 
    Details
    ISSN: 1615-6110
    Schlagwort(e): Heterostyly ; distyly ; zygomorphic flowers ; self-compatibility ; protandry ; geitonogamy ; Lamiaceae ; rare plant species
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Heterostyly rarely occurs in families with strongly zygomorphic flowers. For this reason Darwin (1877) doubted whether heterostyly would occur in the Lamiaceae and recent reviews have not reported the floral polymorphism in this family. Here we describe distyly in a rare species ofSalvia restricted to bluffs and seaward canyons on Santa Rosa Island (Santa Barbara Co., California) and northwestern Baja California (Mexico).Salvia brandegeei is morphologically distylous with populations composed of equal frequencies of long-and short-styled morphs differing reciprocally in stigma and anther position. Controlled hand pollinations demonstrated no significant differences in the seed set of self, intramorph or intermorph pollinations. Unlike most heterostylous species investigated,S. brandegeei does not possess diallelic incompatibility or ancillary polymorphisms of pollen and stigmas. We propose that the evolution of distyly inS. brandegeei may have been associated with an ecological shift to a new environment in which protandry failed to prevent increased levels of geitonogamy. Heterostyly was then selected because it increased the proficiency of cross-pollination. The origin of distyly in self-compatibleS. brandegeei is consistent with Lloyd and Webb's theoretical model for the evolution of distyly.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00985280
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  • 6
    facet.materialart.
    Unbekannt
    Direct simulation of a turbulent oscillating boundary layer (1987)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: The turbulent boundary layer driven by a freestream velocity that varies sinusoidally in time around a zero mean is considered. The flow has a rich behavior including strong pressure gradients, inflection points, and reversal. A theory for the velocity and stress profiles at high Reynolds number is formulated. Well-resolved direct Navier-Stokes simulations are conducted over a narrow range of Reynolds numbers, and the results are compared with the theoretical predictions. The flow is also computed over a wide range of Reynolds numbers using a new algebraic turbulence model; the results are compared with the direct simulations and the theory.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: NASA-TM-89460 , A-87220 , NAS 1.15:89460
    Format: application/pdf
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  • 7
    facet.materialart.
    Unbekannt
    A one-equation turbulence transport model for high Reynolds number wall-bounded flows (1991)
    In:  Other Sources
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: A one-equation turbulence model that avoids the need for an algebraic length scale is derived from a simplified form of the standard-k-epsilon model equations. After calibration based on well established properties of the flow over a flat plate, predictions of several other flows are compared with experiment. The preliminary results presented indicate that the model has predictive and numerical properties of sufficient interest to merit further investigation and refinement. The one-equation model is also analyzed numerically and robust solution methods are presented.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: AIAA PAPER 91-0610
    Format: text
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  • 8
    facet.materialart.
    Unbekannt
    A one-equation turbulence transport model for high Reynolds number wall-bounded flows (1990)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-28
    Beschreibung: A one-equation turbulence model that avoids the need for an algebraic length scale is derived from a simplified form of the standard k-epsilon model equations. After calibration based on well established properties of the flow over a flat plate, predictions of several other flows are compared with experiment. The preliminary results presented indicate that the model has predictive and numerical properties of sufficient interest to merit further investigation and refinement. The one-equation model is also analyzed numerically and robust solution methods are presented.
    Schlagwort(e): FLUID MECHANICS AND HEAT TRANSFER
    Materialart: NASA-TM-102847 , A-90231 , NAS 1.15:102847
    Format: application/pdf
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    facet.materialart.
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    On the use of coherence functions to evaluate sources of dynamic excitation (1979)
    In:  CASI
    Details
    Publikationsdatum: 2019-06-27
    Beschreibung: The use of coherence functions for identifying the relative contributions of multiple dynamic inputs to the measured vibration response of spacecraft components on a practical, complex structure was investigated. Data were generated by applying simultaneous vibratory and acoustic excitation to a test model (a modified Titan instrumentation truss). Up to three inputs were used. In some cases mutually coherent inputs were generated. A digital computer program was written to analyze the test data, using an approach based on iterative computational algorithms. The results showed that the coherence function technique was effective in identifying and evaluating sources of excitation, for both independent and coherent inputs. The effect of varying the number of data samples used in the necessary averaging process was briefly investigated.
    Schlagwort(e): STRUCTURAL MECHANICS
    Materialart: Shock and Vibration Inform. Center The Shock and Vibration Bull., Pt. 1; p 43-58
    Format: text
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  • 10
    facet.materialart.
    Unbekannt
    The use of coherence functions to determine dynamic excitation sources on launch vehicle payloads (1979)
    In:  CASI
    Details
    Publikationsdatum: 2019-07-13
    Beschreibung: The problem of determining the relative contribution of simultaneous acoustic and mechanical inputs to the response of structures under combined dynamic loads was studied. An analytical technique developed by Bendat for calculating ordinary, partial, and multiple coherence functions, using an iterative nonmatrix approach was applied to data obtained from laboratory tests on a complex structural assembly. Testing was performed in an acoustically 'live' room. Up to three random inputs, having similar spectral content and varying degrees of mutual coherence, and a single output were used. Stationary and nonstationary inputs were used. It was concluded that the technique provided an effective method of identifying sources of dynamic excitation and evaluating their relative contributions to the measured output at structural resonances, for stationary random inputs. An attempt to apply the technique to nonstationary inputs did not yield consistent results.
    Schlagwort(e): STRUCTURAL MECHANICS
    Materialart: NASA-CR-3142 , MCR-78-556
    Format: application/pdf
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