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271.
Figueroa FL Escassi L Pérez-Rodríguez E Korbee N Giles AD Johnsen G 《Journal of photochemistry and photobiology. B, Biology》2003,69(1):21-30
The effect of irradiance (40 and 840 micromol photons m(-2) s(-1)) of short-term (48 h) irradiation on photosynthetic activity (estimated as oxygen evolution and as chlorophyll fluorescence), specific absorption and fluorescence excitation spectra, photosynthetic pigment accumulation (chlorophyll a and biliproteins) and UV-absorbing compounds (mycosporine-like amino acids, MAAs) was investigated in sun and shade species of the red algal genus Porphyra collected in Trondheimsfjord (Norway). In the sun type, high irradiance exposure (840 micromol photons m(-2) s(-1)) did not alter the Chl a concentration, however, exposure to a lower irradiance (40 micromol photons m(-2) s(-1)) for 48 h significantly increased the chlorophyll concentration. The content of MAAs was significantly higher in the suntype than in the shade type algae. Porphyra-334 is the main MAA in this species followed by shinorine. The total content of MAAs significantly (P<0.05) increased in the sun type after 48 h exposure to both high and low irradiances. However, in the shade type, porphyra-334 significantly decreased (P<0.05) after both high and low irradiance exposure. Photosynthetic activity (as oxygen evolution) and the optimal quantum yield (F(v)/F(m)), as an indicator of photoinhibition, decreased under low and high irradiance in the shade type algae and no full recovery was observed when the algae were transferred to very low irradiation.The sun type algae presented a higher capacity of acclimation to increased irradiance than the shade type algae. This high acclimation of sun type algae to short term high irradiance exposure (48 h) is explained by the higher thermal dissipation. This was estimated as the ratio of nonphotochemical quenching related to the light dose (q(N):dose) and by the accumulation of MAAs. 相似文献
272.
273.
Forward and Inverse Potential Field Solutions for Cardiac Strands of Cylindrical Geometry 总被引:1,自引:0,他引:1
Ganapathy Nirmala Clark John W. Wilson Owen B. Giles Wayne 《IEEE transactions on bio-medical engineering》1985,(8):566-577
This paper deals with the classical forward and inverse volume conductor field problems associated with the isolated active cardiac muscle preparations of cylindrical geometry. Specifically, these are the Purkinje fiber, the atrial trabeculum, and the (idealized) single atrial cell. The electrical behavior of the multicellular preparations (Purkinje strand and atrial trabeculum) is modeled in terms of the electrical activity of an equivalent single cell, with a representative membrane that separates an anisotropic intracellular medium from an isotropic extracellular medium. The isolated single atrial fiber is considered an interesting special case anid is modeled in an idealized sense as a long cylindrical cell with an isotropic internal medium. A model based on potential theory is developed for the equivalent cardiac cell; it is based on a solution of Laplace's equation in the media of interest, subject to appropriate boundary conditions. The solution for potential at an arbitrary point in the extracellular medium is in the form of a Fourier integral; the equation is subsequently reformulated into a more convenient computational form using a discrete Fourier transform (DFT) method. Implementation of this method, using a fast Fourier transform (FFT) technique, results in a fast and efficient numerical algorithm for the calculation of volume conductor potentials. A benefit of this approach is that the classical forward and inverse problems in electrophysiology may be viewed as equivalent filtering problems. 相似文献
274.
William B. Giles 《Discrete Mathematics》1976,15(4):325-332
The main theorem of this paper states that any tree having at least five vertices can be recovered up to isomorphism from its two point deleted subtrees. The proof makes use of partially labelled trees. 相似文献
275.
Larrabee DC Khodaparast GA Tittel FK Kono J Scalari G Ajili L Faist J Beere H Davies G Linfield E Ritchie D Nakajima Y Nakai M Sasa S Inoue M Chung S Santos MB 《Optics letters》2004,29(1):122-124
Quantum-cascade lasers operating at 4.7, 3.5, and 2.3 THz have been used to achieve cyclotron resonance in InAs and InSb quantum wells from liquid-helium temperatures to room temperature. This represents one of the first spectroscopic applications of terahertz quantum-cascade lasers. Results show that these compact lasers are convenient and reliable sources with adequate power and stability for this type of far-infrared magneto-optical study of solids. Their compactness promises interesting future applications in solid-state spectroscopy. 相似文献
276.
Bowcock T Giles RT Hassard J Kinoshita K Pipkin FM Wilson R Wolinski J Xiao D Gentile T Haas P Hempstead M Jensen T Kagan H Kass R Behrends S Guida JM Guida JA Morrow F Poling R Thorndike EH Tipton P Alam MS Katayama N Kim IJ Sun CR Tanikella V Bortoletto D Chen A Garren L Goldberg M Holmes R Horwitz N Jawahery A Lubrano P Moneti GC Sharma V Csorna SE Mestayer MD Panvini RS Word GB Bean A Bobbink GJ Brock IC Engler A Ferguson T Kraemer RW Rippich C Vogel H Bebek C Berkelman K Blucher E 《Physical review letters》1987,58(4):307-310
277.
Bowcock T Giles RT Hassard J Kinoshita K Pipkin FM Wilson R Haas P Hempstead M Jensen T Kagan H Kass R Behrends S Gentile T Guida JM Guida JA Morrow F Parkhurst G Poling R Rosenfeld C Thorndike EH Tipton P Besson D Green J Namjoshi R Sannes F Skubic P Stone R Bartoletto D Chen A Goldberg M Horwitz N Jawahery A Lubrano P Moneti GC Trahern CG van Hecke H Csorna SE Garren L Mestayer MD Panvini RS Word GB Yi X Alam MS Bean A Ferguson T Avery P Bebek C Berkelman K Cassel DG Copie T DeSalvo R 《Physical review letters》1985,55(9):923-926
278.
Besson D Green J Namjoshi R Sannes F Skubic P Snyder A Stone R Chen A Goldberg M Horwitz N Jawahery A Lipari P Moneti GC Trahern CG van Hecke H Csorna SE Garren L Mestayer MD Panvini RS Yi X Alam MS Avery P Bebek C Berkelman K Cassel DG Copie T DeSalvo R DeWire JW Ehrlich R Ferguson T Galik R Gilchriese MG Gittelman B Halling M Hartill DL Holzner S Ito M Kandaswamy J Kreinick DL Kubota Y Mistry NB Morrow F Nordberg E Ogg M Peterson D Perticone D Read K Silverman A Stein PC Stone S Kezun X 《Physical review letters》1985,54(5):381-384
279.
280.