Structures Related to the Emplacement of Shallow-Level Intrusions

A systematic view of the vast nomenclature used to describe the structures of shallow-level intrusions is presented here. Structures are organised in four main groups, according to logical breaks in the timing of magma emplacement, independent of the scales of features: (1) Intrusion-related structures, formed as the magma is making space and then develops into its intrusion shape; (2) Magmatic flow-related structures, developed as magma moves with suspended crystals that are free to rotate; (3) Solid-state, flow-related structures that formed in portions of the intrusions affected by continuing flow of nearby magma, therefore considered to have a syn-magmatic, non-tectonic origin; (4) Thermal and fragmental structures, related to creation of space and impact on host materials. This scheme appears as a rational organisation, helpful in describing and interpreting the large variety of structures observed in shallow-level intrusions

Southward migration of continental volcanic activity in the Sierra de Las Cruces, Mexico: palaeomagnetic and radiometric evidence

New Palaeomagnetic data for 30 sites (271 samples) and K-Ar data from five units in the Sierra de Las Cruces, western Basin of Mexico, provide constraints on the spatial-temporal evolution of are magmatism in the central Trans-Mexican Volcanic Belt. The normal and reversed directions show a polarity pattern with a consistent spatial zonation perpendicular to the NNW-SSE trend of the range. The magnetostratigraphy and K-Ar dates indicate that volcanic activity in the Sierra de Las Cruces migrated southeastward at a mean rate of 1.6 cm/a, between 3.6 and 1.8 Ma, sind that the rate of migration may have been higher, up to 4 cm/a, during the Gauss Chron. Normal and reversed directions pass the reversal test at a 95% confidence level. The mean Plio-Quaternary palaeomagnetic direction for Sierra de Las Cruces is D =350.7 degrees, I = 30.6 degrees (N = 25, k = 30.7, alpha(95) = 5.3 degrees). The declination deviates to the west of the expected direction, which suggests that small counterclockwise rotations could take place during formation of the Sierra de Las Cruces volcanics. (C) 2000 Elsevier Science B.V. All rights reserved

Experiences of women referred for urgent assessment of postmenopausal bleeding (PMB)

Women with postmenopausal bleeding (PMB) are referred for specialist assessment within 2 weeks of presentation to their GP. No research has previously examined women's experiences of expedited referral. This was investigated in the present study using questionnaires (6-item State Anxiety Inventory (6-STAI)) and focus groups. A total of 55 women completed questionnaires. Results showed high levels of anxiety at first hospital visit (mean 47.0 (SD 14.27); 95% CI 43.14–50.93). Scores declined by 90 days, but were higher in those not undergoing hysteroscopy. Fifteen women who underwent hysteroscopy attended focus groups. Women recalled fear of cancer from symptom onset until receipt of results. Anxiety was exacerbated by poor knowledge of PMB and lack of awareness of expedited referral. Post-discharge, those with unexplained or recurrent symptoms expressed frustration and upset. Effective strategies to raise awareness of PMB and its causes are needed, including reasons for expedited referral. Women without cancer may also need more support

Dissipation of tidal energy by Antarctic ice shelves

FLEXING of ice shelves may dissipate enough tidal energy to have a significant effect on the Moon's retreat from the Earth. It is generally agreed that tidal friction slows the rotation of the Earth and decelerates the Moon in its orbit1. The total energy dissipated can be calculated from observations of the Moon's motion and agrees closely with estimates of the gravitational work done by the Sun and Moon on the ocean tidal bulge2. Therefore dissipation of tidal energy is considered to occur mainly in the ocean with small upper limits being set on energy losses in the Earth's mantle and core. Because the amount of tidal dissipation in shallow seas3 and internal tides4 is uncertain it is of interest to search for additional dissipative mechanisms. In this note the possibility of tidal bending of ice shelves is examined