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  • 1
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    From bedside to bench: lung ultrasound for the assessment of pulmonary edema in animal models (2020)
    Springer
    Details
    Publication Date: 2020-02-03
    Print ISSN: 0302-766X
    Electronic ISSN: 1432-0878
    Topics: Biology , Medicine
    Published by Springer
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    PAPER CURRENT
  • 2
    Electronic Resource
    Electronic Resource
    Aerodynamics of Ephedra trifurca (1986)
    Springer
    Journal of mathematical biology 24 (1986), S. 1-24 
    Details
    ISSN: 1432-1416
    Keywords: Aerodynamics ; Pollination ; Ephedra ; Computer simulations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Mathematics
    Notes: Abstract Computer simulations are used to predict the behavior of pollen grains with different physical properties within the acceleration field created around the ovules of the gymnosperm Ephedra trifurca. A modelling procedure is given that (1) calculates the number of pollen grains captured by an ovule's pollination-droplet and (2) gives a correlation between pollination efficiency and the physical properties (= mass, size) of different types of pollen. Based on this procedure, the number of Ephedra pollen grains captured by micropyles can be less than the number captured from other species. However, the mass and size of Ephedra pollen grains appear to coincide with those predicted to yield a local maximum of pollination efficiency, i.e. slightly larger or smaller values of either mass or size would decrease the probability of capture. In addition, the properties of Ephedra pollen grains operate synergistically in the aerodynamic environment around ovules and are focused to collide with pollination-droplets. By analogy, the properties of Ephedra pollen coincide with those predicted for a localized “adaptive peak”. The physical properties of pollen grain types other than E. trifurca that can maximize pollen capture are not generally represented in the aerobiology of Ephedra during the pollination season. Therefore, the phenology of pollen release, community taxonomic-composition, and the physics of particle capture play collectively important roles in the reproductive success of Ephedra trifurca.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00275718
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  • 3
    Electronic Resource
    Electronic Resource
    A morphometric analysis of the phloem-unloading pathway in developing tobacco leaves (1988)
    Springer
    Planta 176 (1988), S. 307-318 
    Details
    ISSN: 1432-2048
    Keywords: Nicotiana (phloem unloading) ; Phloem unloading ; Photoassimilate unloading ; Translocation (phloem unloading)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A morphometric analysis of developing leaves of Nicotiana tabacum L. was conducted to determine whether imported photoassimilates could be unloaded by symplastic transport and whether interruption of symplastic transport could account for termination of import. Five classes of veins were recognized, based on numbers of cells in transverse section. Photoassimilate is unloaded primarily from Class III veins in tissue nearing the end of the sink phase of development. Smaller veins (Class IV and V) do not transport or unload photoassimilate in sink tissue because the sieve elements of these veins are immature until after the tissue stops importing. In Class III veins the sieve element-companion cell (SE-CC) complexes are surrounded by phloem parenchyma which abuts the bundle sheath. Along the most obvious unloading route, from SE-CC complex to phloem parenchyma to bundle sheath to mesophyll cells, the frequency of plasmodesmata at each interface increases. To determine whether this pattern of plasmodesmatal contact is consistent with symplastic unloading we first demonstrated, by derivation from Fick's law that the rate of diffusion from a compartment is proportional to a number N which is equal to the ratio of surface area to volume of the compartment multiplied by the frequency of pores (plasmodesmata) which connect it to the next compartment. N was calculated for each compartment within the vein which has the SE-CC complex as its center, and was shown to be statistically the same in all cases except one. These observations are consistent with a symplastic unloading route. As the leaf tissue matures and stops importing, plasmodesmatal frequency along the unloading route decreases and contact area between cells also decreases as intercellular spaces enlarge. As a result, the number of plasmodesmata between the SE-CC complex and the first layer of mesophyll cells declines in nonimporting tissue to 34% of the number found in importing tissue, indicating that loss of symplastic continuity between the phloem and surrounding cells plays a role in termination of photoassimilate unloading.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00395411
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  • 4
    Electronic Resource
    Electronic Resource
    The effect of leaf-lobing on the interception of direct solar radiation (1989)
    Springer
    Oecologia 80 (1989), S. 59-64 
    Details
    ISSN: 1432-1939
    Keywords: Leaf-lobing ; Light interception ; Thermal load
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The extent to which leaf-lobing influences the interception of direct solar radiation by individual plants was studied by means of computer simulations. The morphology, size and orientation ofAmbrosia artemisiifolia L. leaves were measured and used to construct a prototypeAmbrosia plant upon which a computer simulation was based. The leaf geometries of this simulation were then varied, and daily integrated irradiances (DII) were calculated for each variant plant simulation. Data indicate that lobedAmbrosia leaves do not confer an advantage to light-interception based upon values of DII. Simulated plants identical in all respects to the prototype, but with simple, elliptic leaves, had equivalent DII values to the prototype. Simulations with leaves in which gaps between lobes were “filledin” had reduced light-interception efficiencies compared to the prototype and to a simulation with elliptic-leaves. Lightinterception was maximized when leaves on distal nodes wereAmbrosia-like and leaves on proximal nodes were elliptic. The data are interpreted to indicate that lobingperse is not functionally advantageous to light-interception; however, gradients of leaf-lobing along the length of shoots may be very significant in terms of overall light interception.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00789932
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  • 5
    Electronic Resource
    Electronic Resource
    Disclosure of defects in YAG crystals by the thermoluminescence method (1984)
    Springer
    Applied physics 35 (1984), S. 249-253 
    Details
    ISSN: 1432-0630
    Keywords: 61.70 ; 61.80 ; 71.35 ; 78.55
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The topograms revealing the anisotropic distribution of defects in the volume of monocrystalline YAG samples have been obtained by the thermoluminescence (TL) technique. It has also been shown that the anisotropic distribution of the lattice defects affects strongly the shape of the TL curves. The greatest changes in the TL intensity were observed in the areas of the samples distributed symmetrically every 120°. It was noted that the selective distribution of the TL intensity is caused mainly by the presence of the (211) facets as well as growth striations formed during the growth process. The groups of lines observed in the TL spectrum have been ascribed to the Tb3+ ions, excited owing to the radiationless energy transfer from the bound exciton states (BES).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00617175
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  • 6
    Electronic Resource
    Electronic Resource
    Thermoluminescence of YAG:Nd crystals coloured with x-rays (1984)
    Springer
    Applied physics 34 (1984), S. 87-92 
    Details
    ISSN: 1432-0649
    Keywords: 61.70 ; 61.80 ; 71.35 ; 78.55
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The spectral distribution of the thermoluminescence (TL) of YAG:Nd crystals coloured by x-ray irradiation at room temperature (RT) and at 80 K has been investigated. The spectral distribution of TL in the uv-, visible and near ir ranges shows that the energy transfer by bound exciton states (BES) to the RE3+ ions (Nd3+ and Tb3+) decreases with increasing temperature. The TL spectrum in the uv range is ascribed to the hole defect centers. Diminution of the energy transferred by the BES to the Nd3+ and Tb3+ ions is the direct cause for the occurrence of the group of lines ascribed to the Nd3+ ions in TL observed at LT, whereas at RT and higher only the groups of Tb lines are observed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00697953
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  • 7
    Electronic Resource
    Electronic Resource
    EPR and ENDOR investigations of Sn impurities in CdS (1988)
    Springer
    The European physical journal 70 (1988), S. 491-497 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Wurtzite type CdS single crystals with tin impurities have been reinvestigated by means of magnetic resonance. The by far strongest neighbour interaction with the rare isotope33S is detectable by electron paramagnetic resonance (EPR), while nine weaker cadmium interactions can be resolved with the electron nuclear double resonance (ENDOR) technique. Three distinct shell symmetries are detected and can be explained by the wurtzite lattice symmetry. The parameters evaluated are interpreted in terms of the LCAO approach. An additional Sn-related spectrum, being not resolvable by ordinary EPR was identified by means of ENDOR-induced-EPR (EI-EPR) and turned out to be associated with Lithium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01312124
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  • 8
    Electronic Resource
    Electronic Resource
    Influence of magnetic fields on taylor vortex formation in magnetic fluids (1987)
    Springer
    The European physical journal 68 (1987), S. 493-501 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The flow of a magnetic fluid placed inside a small gap between concentric rotating cylinders is investigated for axial, radial and azimuthal magnetic fields. An equation of motion is derived phenomenologically to describe the hydrodynamics of magnetic fluids. Studied are the changes in the critical Taylor numberT c and wave numberT c which characterize the instability of primary circular Couette flow towards Taylor vortices. It is found that all above magnetic fields have a stabilizing effect on circular Couette flow and thatT c increases or decreases, depending on the direction of the magnetic field. Besides this, the influence of the magnetic fields on the correlation length ξ0, the wave number of maximal growthk m and the linear growth rate amplitude σ0 is determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01471080
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  • 9
    Electronic Resource
    Electronic Resource
    Thermostimulated luminescence of crystals of neodymium-doped lutecium-yttrium scandates (1981)
    Springer
    Journal of applied spectroscopy 34 (1981), S. 283-286 
    Details
    ISSN: 1573-8647
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00614055
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  • 10
    Electronic Resource
    Electronic Resource
    Deformation effects in the12C-12C system (1986)
    Springer
    The European physical journal 323 (1986), S. 27-39 
    Details
    ISSN: 1434-601X
    Keywords: 21.60 Jz
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The quantized adiabatic time dependent Hartree-Fock (quantized ATDHF) theory is applied to the12C-12C-system. Especially the intrinsic oblate ground state deformation of this nucleus is considered. For four relevant mutual orientations of the two nuclei the optimal, i.e. maximally decoupled collective paths, associated to relative motion, are evaluated by solving a coupled set of nonlinear differential equations on three dimensional grids in coordinate and momentum space. In a second step, the constituents of the corresponding collective Hamiltonian are calculated. Besides the collective potentials this includes the evaluation of the appropriate mass parameters, of the quantum corrections with regard to rotation, translation and collective relative motion and of the centrifugal potentials, all of which are shown to be important. By means of generalized WKB methods, subbarrier fusion cross sections are evaluated for different assumptions on the reaction process and compared with experimental data. Finally, the collective Hamiltonian is calculated for a head-on-collision of two12C-chains.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01294552
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