Use of Otolith Strontium:Calcium Ratios for Hindcasting Larval Cod Gadus Morhua Distributions Relative to Water Masses on Georges Bank

The concentration ratios of strontium to calcium in laboratory-reared larval cod otoliths are shown to be related to the water temperature (T) at the time of otolith precipitation. This relationship is curvilinear, and is best described by a simple exponential equation of the form (Sr/Ca x 1000 = a exp(-T/b). We show that when Sr/Ca elemental analyses are related to the daily growth increments in the larval otoliths, relative temperature histories of individual field-caught larvae can be reconstructed from the egg stage to the time of capture. We present preliminary examples of how such reconstructed temperature histories of Atlantic cod Gadus morhua larvae, collected on Georges Bank during April and May 1993, may be interpreted in relation to the broad-scale larval distributions and the hydrography of the Bank.

A LAPLACE TRANSFORM PAIR MODEL TO DETERMINE BREMSSTRAHLUNG SPECTRA FROM ATTENUATION DATA (RADIATION, X-RAY, SPECTRAL MODELING)

Every x-ray attenuation curve inherently contains all the information necessary to extract the complete energy spectrum of a beam. To date, attempts to obtain accurate spectral information from attenuation data have been inadequate.^ This investigation presents a mathematical pair model, grounded in physical reality by the Laplace Transformation, to describe the attenuation of a photon beam and the corresponding bremsstrahlung spectral distribution. In addition the Laplace model has been mathematically extended to include characteristic radiation in a physically meaningful way. A method to determine the fraction of characteristic radiation in any diagnostic x-ray beam was introduced for use with the extended model.^ This work has examined the reconstructive capability of the Laplace pair model for a photon beam range of from 50 kVp to 25 MV, using both theoretical and experimental methods.^ In the diagnostic region, excellent agreement between a wide variety of experimental spectra and those reconstructed with the Laplace model was obtained when the atomic composition of the attenuators was accurately known. The model successfully reproduced a 2 MV spectrum but demonstrated difficulty in accurately reconstructing orthovoltage and 6 MV spectra. The 25 MV spectrum was successfully reconstructed although poor agreement with the spectrum obtained by Levy was found.^ The analysis of errors, performed with diagnostic energy data, demonstrated the relative insensitivity of the model to typical experimental errors and confirmed that the model can be successfully used to theoretically derive accurate spectral information from experimental attenuation data. ^

Georges Duhamel: Spiegel der Zukunft [Rezension]

N. H.

Georges Bizet, Brustbild

Signatur des Originals: S 36/F00161

Georges Kastner, Kniestück

Signatur des Originals: S 36/F00917

Georges Bizet, Brustbild

Signatur des Originals: S 36/F03054

Georges Bizet, Brustbild

Signatur des Originals: S 36/F03055

Martha Bommer als Carmen, Rollenbild, in: Georges Bizet: Carmen

Signatur des Originals: S 36/F03104

Richard Breitenfeld als Escamillo, Rollenbild, Kniestück, in: Georges Bizet: Carmen

Signatur des Originals: S 36/F03180

Richard Breitenfeld als Escamillo, Rollenbild, Ganzfigurbildnis, in: Georges Bizet: Carmen

Signatur des Originals: S 36/F03181

Robert Burg als Escamillo, Rollenbild, Hüftbild, in: Georges Bizet: Carmen

Signatur des Originals: S 36/F03273

Jean Buysson als Don José, Rollenbild, in: Georges Bizet: Carmen

Signatur des Originals: S 36/F03307

Enrico Caruso als Don José, Rollenbild, Brustbild, Georges Bizet: Carmen

Signatur des Originals: S 36/F03321

Enrico Caruso als Don José, Rollenbild, Brustbild, in: Georges Bizet: Carmen

Signatur des Originals: S 36/F03322

Enrico Caruso als Don José, Rollenbild, Brustbild, in Georges Bizet: Carmen

Signatur des Originals: S 36/F03325