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  • 1995-1999  (3)
  • 1930-1934
  • 1998  (3)
  • Cavitation  (1)
  • Communication  (1)
  • Engineering  (1)
  • Malondialdehyde
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Behavioral ecology and sociobiology 43 (1998), S. 47-58 
    ISSN: 1432-0762
    Keywords: Key wordsStingless bee ; Communication ; Pheromone ; Scent beacon ; recruitment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Melipona panamica foragers can deposit a scent beacon that influences the orientation of foragers near a food source. In misdirection experiments, newcomers (bees from the same colony as trained foragers) consistently preferred the feeder at which trained foragers had fed (training feeder) over an identical feeder at which bees had never fed (control feeder) even when the training feeder was placed at a site where experienced foragers had never foraged. Through similar misdirection experiments, the effective radius of the scent beacon was determined to be greater than 6 and less than 12 m. Foragers may deposit this beacon during a sequence of departure behaviors performed at the feeder. Prior to leaving the feeder with a load of sugar solution, bees tended to perform the following sequence of behaviors: (1) spinning, (2) grooming, (3) abdomen dragging, (4) excreting anal droplets, and (5) producing sounds, although not all behaviors were performed prior to each departure or at all sucrose concentrations (0.5–2.5 m). As sucrose concentration increased, the number of newcomers significantly increased, and the number of experienced foragers producing sounds and spinning on the feeder increased. The exact source of the scent beacon remains a mystery. However, three important sources have been excluded. When choosing between identical paired feeders, foragers were not attracted to the feeders with (1) anal droplets, (2) extracts of sucrose solution at which foragers had fed, or (3) mandibular gland extracts. They were indifferent to the first two preparations and exhibited only typical alarm behavior towards the mandibular gland (MG) extract: they oriented towards the feeder with MG extract but consistently landed on the feeder with no MG extract. Other authors have suggested that Melipona foragers deposit anal droplets to attract recruits, however the frequency of anal droplet production and the mass of anal droplets produced by M. panamica foragers are negatively correlated with sucrose concentration. Thus the scent beacon is evidently not deposited with anal droplets, infused into the feeder solution, or produced by mandibular glands.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-0603
    Keywords: Cavitation ; Cell injury ; Shock wave lithotripsy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Increased ambient pressure (excess hydrostatic pressure) was used to regulate cavitation in the aqueous media surrounding isolated red blood cells and aluminum foils used as targets in studies of the mechanisms of shock wave (SW) damage in shock wave lithotripsy (SWL). Foils or cells were placed in a cylindrical chamber (bronze-aluminum alloy) connected to a regulator and nitrogen source. The ends of the cylinder were capped with planar, plastic plates 12.7 mm thick. Tests performed with a PVDF membrane hydrophone showed that SW's passed through the plastic without significant loss of amplitude or change in waveform. Pitting of foils, a form of damage that can only be due to cavitation, was eliminated by very high (∼70 atm) added pressure. It took substantially greater added pressure to reduce damage to foils than has been reported to reduce damage to cells, suggesting differences in how cavitation is regulated in bulk fluid versus a solid surface. This report describes the design of the pressure chamber used in these studies and explains how SW exposures of isolated cells and foil targets were performed.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester [u.a.] : Wiley-Blackwell
    International Journal for Numerical Methods in Engineering 42 (1998), S. 1215-1229 
    ISSN: 0029-5981
    Keywords: boundary element method ; fast multipole method ; many-particle problem ; linear elasticity ; iterative solution strategy ; Engineering ; Numerical Methods and Modeling
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mathematics , Technology
    Notes: A boundary element method for solving three-dimensional linear elasticity problems that involve a large number of particles embedded in a binder is introduced. The proposed method relies on an iterative solution strategy in which matrix-vector multiplication is performed with the fast multipole method. As a result the method is capable of solving problems with N unknowns using only O(N) memory and O(N) operations. Results are given for problems with hundreds of particles in which N=O(105). © 1998 John Wiley & Sons, Ltd.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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