The visualization of turbulence data using a wavelet‐based method

This technical communication presents some MATLAB^® routines for visualizing the structure in turbulent signals based on a standard conditional averaging and thresholding approach. Up to three velocity components may be analysed and the resulting output highlights the time at which important flow events occur as well as the frequency levels that contribute the greatest energy to this particular event. The latter information is derived from a wavelet decomposition of the signal and may assist in providing a process‐based explanation of observed flow features. Copyright © 2006 John Wiley & Sons, Ltd.     

Botswana gravity reference net

Gravity reference stations for the National Gravity Survey of Botswana have been established at twenty-three sites throughout the country in a net linked to existing bases in South Africa, Kenya and Zambia with an internal accuracy of better than 0.5 gravity units (one gravity unit, gu, equals an acceleration of 10⁻⁶ m.s⁻²). The field procedure and reduction of data are explained and a list is given of the gravity values.     

Automated Image Registration for Hydrologic Change Detection in the Lake-Rich Arctic

Multitemporal remote sensing provides a unique tool to track lake dynamics at the pan-Arctic scale but requires precise registration of thousands of satellite images. This is a challenging task owing to a dearth of stable features to be used as tie points [(TPs), i.e., control points] in the dynamic landscapes. This letter develops an automated method to precisely register images in the lake-rich Arctic. The core premise of the method is that the centers of lakes are generally stable even if their shorelines are not. The proposed procedures first extract lakes in multitemporal satellite images, derive lake centroids and match them between images, and then use the centroids of stable lakes as TPs for image registration. The results show that this approach can achieve subpixel registration accuracy, outcompeting the conventional manual methods in both efficiency and accuracy. The proposed method is fully automated and represents a feasible way to register images for lake change detection at the pan-Arctic scale.      

Iron ore workings near Horsham,Sussex, and the sedimentology of Wealden clay ironstone

The distribution of old workings, or ‘minepits’, for clay ironstone in an area between Horsham and Crawley is shown on geological sketch-maps. The geological structure of the area is described in outline. The old workings, except for those in two anomalous patches, are restricted to two argillaceous units in the Upper Tunbridge Wells Sand and to an ironstone horizon some 2 m. below the Horsham Stone in the Weald Clay. Slags from two bloomery sites are described. The amount of ore dug from the minepits is estimated to correspond roughly to the requirements of local blast furnaces, of sixteenth- and seventeenth-century date. Depletion of iron ore reserves is suggested as a factor deciding against resumption of the iron industry in the area after the Civil War.     

Zinc content in otoliths of mackerel from the Aegean

The zinc content in otoliths of the mackerel (Scomber japonicus colias) has been determined by instrumental neutron activation analysis. Six groups each of twelve specimens of the same age selected from three areas of the Aegean sea have been analysed. The zinc content was found to be a linear function of the age and body length.     

Geordnete Deponie von festen Siedlungs- und geeigneten Industrieabfällen

Ohne Zusammenfassung     

Ontogeny ofHybocrinus punctatus (Miller and Gurley), an ordovician crinoid

Relative growth of the Ordovician crinoid Hybocrinus punctatus (Miller and Gurley)was studied using regression, correlation, and R-mode factor analysis. Systematic growth gradients of both initial intercepts and slopes existed throughout the calyx. Development of a single plate was best correlated with growth of the directly adjacent plates and was less well correlated with that of more distant plates. A total of 86 percent of the R-mode correlation matrix variance is associated with overall size increase of all dimensions and size-correlated shape changes. Most of the remaining variance is linked with divergent growth of small groups of specimens with respect to various shape parameters.