Beschreibung: The main phase of the 2013 March 17 storm had excellent coverage from ground-based instruments and from low- and high-altitude spacecraft, allowing for evaluation of the relations between major storm-time phenomena that are often considered separately. The shock impact with its concurrent southward IMF immediately drove dramatic poleward expansion of the poleward boundary of the auroral oval (implying strong nightside reconnection), strong auroral activity, and strong penetrating mid-latitude convection and ionospheric currents. This was followed by periods of southward IMF driving of electric fields that were at first relatively smooth as often employed in storm modeling, but then became extremely bursty and structured associated with equatorward extending auroral streamers. The auroral oval did not expand much further poleward during these two latter periods, suggesting a lower overall nightside reconnection rate than that during the first period and approximate balance with dayside reconnection. Characteristics of these three modes of driving were reflected in horizontal and field-aligned currents. Equatorward expansion of the auroral oval occurred predominantly during the structured convection mode, when electric fields became extremely bursty. The period of this third mode also approximately corresponded to the time of largest equatorward motion of the ionospheric trough, of apparent transport of high TEC features into the auroral oval from the polar cap, and of largest earthward injection of ions and electrons into the ring current. The enhanced responses of the aurora, currents, TEC, and the ring current indicate a common driving of all these stormtime features during the bursty convection mode period.

Beschreibung: [1]  Poleward boundary intensifications (PBIs) are auroral intensifications along the poleward boundary of the auroral oval and occur during all levels of geomagnetic activity. However, little is known about the triggering of PBIs. Recent case studies have indicated the existence of longitudinally localized flow channels in the polar cap near, and directed towards, the nightside open-closed field line boundary just before PBIs. Motivated by these studies, we analyze 115 events of coordinated observations by the THEMIS all-sky imager and SuperDARN HF radar at Rankin Inlet to determine if this polar cap flow-PBI relationship is commonly observed. We start with isolated and intense PBIs and examine the probability of them being associated with equatorward-directed polar cap flows. Our results show the association to be frequent (90%), with one-to-one correlations occurring in ~50% of events. Considering the limitations of the radar observations, this result indicates that PBIs are commonly correlated with polar cap flow channels directed towards, and then traversing, the open-closed field line boundary. The flows statistically occur ~1-2 min before the PBI initiations, and the duration and width of the flows are comparable to those of the PBIs. We also perform a reverse study by starting with isolated polar cap flows and obtain similar results. The remarkably high occurrence of association between enhanced polar cap flows and PBIs indicates that enhanced meso-scale flows within the open field line region that traverse the open-closed field line boundary are an important driver of PBI formation.

Beschreibung: Background— Heterozygous familial hypercholesterolemia (HeFH) is a common genetic disorder leading to premature coronary artery disease. Despite statins and additional lipid-lowering therapies, many HeFH patients fail to achieve low-density lipoprotein cholesterol (LDL-C) goals. We evaluated mipomersen, an apolipoprotein B synthesis inhibitor, to further lower LDL-C in HeFH patients with coronary artery disease. Methods and Results— This double-blind, placebo-controlled, phase 3 trial randomized patients with HeFH and coronary artery disease on maximally tolerated statin and LDL-C ≥2.6 mmol/L (≥100 mg/dL) to weekly subcutaneous mipomersen 200 mg or placebo (2:1) for 26 weeks. The primary end point was percent change in LDL-C from baseline at week 28. Safety assessments included adverse events, laboratory tests, and magnetic resonance imaging assessment of hepatic fat. Of 124 randomized patients (41 placebo, 83 mipomersen), 114 (41 placebo, 73 mipomersen) completed treatment. Mean (95% confidence interval) LDL-C decreased significantly with mipomersen (–28.0% [–34.0% to –22.1%] compared with 5.2% [–0.5% to 10.9%] increase with placebo; P 〈0.001). Mipomersen significantly reduced apolipoprotein B (–26.3%), total cholesterol (–19.4%), and lipoprotein(a) (–21.1%) compared with placebo (all P 〈0.001). No significant change occurred in high-density lipoprotein cholesterol. Adverse events included injection site reactions and influenza-like symptoms. Five mipomersen patients (6%) had 2 consecutive alanine aminotransferase values ≥3 times the upper limit of normal at least 7 days apart; none were associated with significant bilirubin increases. Hepatic fat content increased a median of 4.9% with mipomersen versus 0.4% with placebo ( P 〈0.001). Conclusions— Mipomersen is an effective therapy to further reduce apolipoprotein B–containing lipoproteins, including LDL and lipoprotein(a), in HeFH patients with coronary artery disease on statins and other lipid-lowering therapy. The significance of hepatic fat and transaminase increases remains uncertain at this time. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00706849.