The response of ionospheric convection in the polar cap to substorm activity

We report multi-instrument observations during an isolated substorm on 17 October 1989. The EISCAT radar operated in the SP-UK-POLI mode measuring ionospheric convection at latitudes 71°-78°. SAMNET and the EISCAT Magnetometer Cross provide information on the timing of substorm expansion phase onset and subsequent intensifications, as well as the location of the field aligned and ionospheric currents associated with the substorm current wedge. IMP-8 magnetic field data are also included. Evidence of a substorm growth phase is provided by the equatorward motion of a flow reversal boundary across the EISCAT radar field of view at 2130 MLT, following a southward turning of the interplanetary magnetic field (IMF). We infer that the polar cap expanded as a result of the addition of open magnetic flux to the tail lobes during this interval. The flow reversal boundary, which is a lower limit to the polar cap boundary, reached an invariant latitude equatorward of 71° by the time of the expansion phase onset. A westward electrojet, centred at 65.4°, occurred at the onset of the expansion phase. This electrojet subsequently moved poleward to a maximum of 68.1° at 2000 UT and also widened. During the expansion phase, there is evidence of bursts of plasma flow which are spatially localised at longitudes within the substorm current wedge and which occurred well poleward of the westward electrojet. We conclude that the substorm onset region in the ionosphere, defined by the westward electrojet, mapped to a part of the tail radially earthward of the boundary between open and closed magnetic flux, the “distant” neutral line. Thus the substorm was not initiated at the distant neutral line, although there is evidence that it remained active during the expansion phase. It is not obvious whether the electrojet mapped to a near-Earth neutral line, but at its most poleward, the expanded electrojet does not reach the estimated latitude of the polar cap boundary

GATA-3 Has Dual Regulatory Functions in Human Interleukin-5 Transcription

Interleukin-5 (IL-5) is a T-cell cytokine involved in Type 2 diseases and is commonly described as being coordinately regulated with other Type 2 cytokines, such as IL-4 and IL-13. Considering the unique control of eosinophilia by IL-5, such coordinate regulation would be surprising. In fact, the biological specificity of eosinophilia and its control by IL-5 suggests a unique and independent control of IL-5 regulation. In this report we show the binding of GATA-3 to three sites in the human IL-5 promoter in the human T-cell line PER117. The previously identified -70 site and another site at position - 152 are shown to positively regulate IL-5 transcription. More importantly, the site located at -400 acts as a powerful repressor of IL-5 transcription with mutagenesis of this site allowing a high level expression of IL-5 without the activation of other factors normally required for IL-5 expression. Whereas GATA-3 has been proposed to be involved in the regulation of the IL-4/IL-5/ IL-13 locus, we show here that it has another function in controlling IL-5 transcription that supports the observed unique biological function of this cytokine.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Evaluation of drop size and two-component velocity measurement technique in annular two-phase flow

4.00SIGLEAvailable from British Library Lending Division - LD:9091.9F(AERE-R--11355) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

The use of calibration techniques for the development and application of optical particle sizing instruments

5.00Available from British Library Document Supply Centre- DSC:9091.9F(AERE-R--12601) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Plasma flow bursts in the nightside auroral zone ionosphere and their relation to geomagnetic activity

We examine the nature of flows in the nightside auroral zone ionosphere and their relationship with concurrent geomagnetic activity by studying a three-hour interval of ground-based radar, magnetometer array and spacecraft data. We find that the flows are bursty in nature, a characteristic previously reported, and that the bursts are related to a series of substorm electrojet intensifications initiated in the pre-midnight sector