SHATTER CONES AT GLOVER BLUFF,WISCONSIN

Shatter cones were discovered at Glover Bluff, Wisconsin. Coordinates are: N 43° 58.2′ W 089° 32.3′.     

High-frequency oscillations in a solar active region coronal loop

The Solar Eclipse Corona Imaging System (SECIS) was used to record high-cadence observations of the solar corona during the total solar eclipse of 1999 August 11. During the 2 min 23.5 s of totality, 6364 images were recorded simultaneously in each of the two channels: a white light channel, and the Fe  xiv (5303 Å) 'green line' channel ( T ∼2 MK) . Here we report initial results from the SECIS experiment, including the discovery of a 6-s intensity oscillation in an active region coronal loop.     

Hadley circulations and Kelvin wave-driven equatorial jets in the atmospheres of Jupiter and Saturn

We propose a dynamical mechanism that can plausibly explain the origin of the broad prograde equatorial winds observed on Jupiter and Saturn, and examine the feasibility of this mechanism using two- (2D) and three-dimensional (3D) numerical simulation models. The idea is based on combining a narrow Gaussian jet peaking at the equator, which is induced by the momentum transfer from an upward propagating equatorial Kelvin-wave, and a pair of off-equatorial jets due to a meridional-vertical circulation similar to the tropical Hadley circulation on Earth. We employ for this feasibility study a 2D mechanistic mean-flow model which incorporates the influence of prescribed waves, and a 3D general circulation model, based on the generalised primitive equations of atmospheric motion. We then confirm that the dynamical models of both kinds can successfully reproduce theoretically expected flows of a reasonable magnitude, and that when two mechanisms are combined, a broad super-rotating jet is produced with off-equatorial maxima in zonal velocity for both Jupiter and Saturn, approximately in accordance with observations.     

XMM–Newton Reflection Grating Spectrometer observations of the prototypical starburst galaxy M82

We present results from XMM–Newton Reflection Grating Spectrometer observations of the prototypical starburst galaxy M82. These high-resolution spectra represent the best X-ray spectra to date of a starburst galaxy. A complex array of lines from species over a wide range of temperatures is seen, the most prominent being due to Lyman α emission from abundant low- Z elements such as N, O, Ne, Mg and Si. Emission lines from helium-like charge states of the same elements are also seen in emission, as are strong lines from the entire Fe L series. Further, the O vii line complex is resolved and is seen to be consistent with gas in collisional ionization equilibrium.
Spectral fitting indicates emission from a large mass of gas with a differential emission measure over a range of temperatures (from ∼ 0.2 to ∼ 1.6 keV, peaking at ∼ 0.7 keV), and evidence for super-solar abundances of several elements is indicated. Spatial analysis of the data indicates that low-energy emission is more extended to the south and east of the nucleus than to the north and west. Higher energy emission is far more centrally concentrated.     

Defining and detecting undesirable disturbance in the context of marine eutrophication

An understanding of undesirable disturbance to the balance of organisms is needed to diagnose marine eutrophication as defined by EU Directives and OSPAR. This review summarizes the findings of the UK Defra-funded Undesirable Disturbance Study Team, which concluded that 'an undesirable disturbance is a perturbation of a marine ecosystem that appreciably degrades the health or threatens the sustainable human use of that ecosystem'. A methodology is proposed for detecting disturbance of temperate salt-water communities dominated by phytoplanktonic or phytobenthic primary producers. It relies on monitoring indicators of ecosystem structure and vigour, which are components of health. Undesirable disturbance can be diagnosed by accumulating evidence of ecohydrodynamic type-specific changes in: (i) bulk indicators; (ii) frequency statistics; (iii) flux measurements; (iv) structural indicators; and (v) indicator species. These are exemplified by (i) chlorophyll, transparency, dissolved oxygen, and opportunistic seaweed cover; (ii) HABs frequency; (iii) primary production; (iv) benthic and planktonic 'trophic indices'; (v) seagrasses and Nephrops norvegicus. Ecological Quality Objectives are proposed for some of these. Linking the diagnosis to eutrophication requires correlation of changes with nutrient enrichment. The methodology, which requires the development of a plankton community index and emphasizes the importance of primary production as an indicator of vigour, can be harmonized with the EU Water Framework Directive and OSPAR's Strategy to Combat Eutrophication.     

Pre-treatment of feed for dry magnetic separation of fine materials

Changes in the flow properties of the feed to an induced-roll magnetic separator have been shown to have a marked effect on the efficiency of its operation. The optimisation of the feeding system and removal of the ultrafines (?10 μm) from the feed have both been found to be viable methods for achieving good dry magnetic separations of fine mineral mixtures. Series of experiments have been performed on hematite/limestone and cassiterite/wolframite separations.