Sceloporus slevini

Number of Pages: 6Integrative BiologyGeological Science

Shafranov's virial theorem and magnetic plasma confinement

Shafranov's virial theorem implies that nontrivial magnetohydrodynamical equilibrium configurations must be supported by externally supplied currents. Here we extend the virial theorem to field theory, where it relates to Derrick's scaling argument on soliton stability. We then employ virial arguments to investigate a realistic field theory model of a two-component plasma, and conclude that stable localized solitons can exist in the bulk of a finite density plasma. These solitons entail a nontrivial electric field which implies that purely magnetohydrodynamical arguments are insufficient for describing stable, nontrivial structures within the bulk of a plasma.Comment: 9 pages no figure

Stroke in Devon: knowledge was good, but action was poor.

BACKGROUND AND AIM: Effective implementation of early treatment strategies for stroke requires prompt admission to hospital. There are several reasons for delayed admission. Good awareness should facilitate early admission. We identified local targets for education. METHODS: Four groups, each of 40 people, completed questionnaires to determine their knowledge of stroke symptoms and risk factors, and the action they took or would take in the event of a stroke. The groups were: patients with a diagnosis of stroke or TIA (within 48 hrs of admission); patients at risk of stroke; the general population; and nurses. RESULTS: Forty per cent of stroke patients identified their stroke. Median time from onset of symptoms to seeking medical help was 30 minutes. Medical help was sought by the patient themselves in only 15% of cases. In 80% of cases the GP was called rather than an ambulance. Of the at risk group, 93% were able to list at least one symptom of acute stroke, as were 88% of the general population. An ambulance would be called by 73% of the at risk group in the event of a stroke. Patients with self reported risk factors for stroke were largely unaware of their increased risk. Only 7.5% of at risk patients acquired their stroke information from the medical profession. CONCLUSIONS: Public knowledge about stroke is good. However, stroke patients access acute services poorly. At risk patients have limited awareness of their increased risk. A campaign should target people at risk, reinforcing the diagnosis of stroke and access to medical services