In the red zone
Article Abstract:
Statistical models for the composition of temporal fluctuations in natural populations is of importance for the study of population biology. Population models predict the domination of high frequencies in the power spectra of chaotic time series. This indicates that the one-dimensional difference equations are unsuitable for predicting fluctuations in population dynamics. Population models show the presence of 'blue' statistical spectra, and have a parametric range where the fluctuations are chaotic but the spectra are reddened.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1996
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High-efficiency multilevel zone plates for keV X-rays
Article Abstract:
High-efficiency, high-contrast gold and nickel multistep Fresnel zone plates were fabricated using electron beam lithography. Maximum efficiency of 55% was achieved for the nickel plate at 7 keV. The lenses also have low background signal and unwanted diffraction orders are effectively reduced. They could be of use in techniques such as microscopy, micro-fluorescence and micro-diffraction.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1999
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Megaripple migration in a natural surf zone
Article Abstract:
Migrating megaripples are seen in the surf zone of sandy coasts. They affect overlying currents through the introduction of hydraulic roughness. Their formation, orientation and migration is not well understood. It is suggested that megaripples do not migrate in the direction of the vector sum of the currents, but are aligned to maximize sediment transport normal to the bedform crest.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1998
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