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The Montreal Protocol is working. Concentrations of major ozone-depleting substances in the atmosphere are now decreasing, and the decline in total column amounts seen in the 1980s and 1990s at mid-latitudes has not continued. In polar regions, there is much greater natural variability. Each spring, large ozone holes continue to occur in Antarctica and less(More)
Craniotomy using stereotactic techniques has the potential to improve the extent of tumor resection and to reduce wound and neurologic morbidity. Most reports of stereotaxy-assisted craniotomy (SC) for tumor resection have focused on techniques using sophisticated computer hardware and volumetric software. Results of nonvolumetric SC in 50 consecutive cases(More)
Interactive frameless stereotaxy has been successfully applied to intracranial surgery. It has contributed to the improved localization of deep-seated brain lesions and has demonstrated a potential for reducing both operative time and morbidity. However, it has not been as effectively applied to spinal surgery. The authors describe the application of(More)
Chlorine- and bromine-containing ozone-depleting substances (ODSs) are controlled by the 1987 Montreal Protocol. In consequence, atmospheric equivalent chlorine peaked in 1993 and has been declining slowly since then. Consistent with this, models project a gradual increase in stratospheric ozone with the Antarctic ozone hole expected to disappear by ∼2050.(More)
Comment on " Record solar UV irradiance in the tropical Andes, by Cabrol et al. " Recently Cabrol et al. (2014), hereafter C14, reported measurements of the UV Index (UVI) reaching 43.3 at a high altitude location in the Andes (Licancabur; 22.5 • S, 67.5 • W, 5917 m a.s.l.). This value is much larger than those previously reported from other high altitude(More)
Spinal instrumentation and frameless stereotaxy are two separate fields in neurosurgery that have rapidly advanced in recent years. The application of stereotaxis to spinal surgery has previously been limited by the inaccuracy of surface mounted reference points. The development of frameless stereotaxy using anatomical registration techniques has overcome(More)
The role and timing of a carotid endarterectomy in the setting of an acute ischemic stroke-in-evolution remain controversial. Although computed tomographic (CT) scans typically show no abnormalities in the acute stage, it is generally agreed that a dense neurological deficit (hemiplegia) and/or multiple modality neurological disturbance (involving motor,(More)
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