A new auroral phenomenon, the anti-black aurora

Black auroras are small-scale features embedded in the diffuse background aurora, typically occurring post-substorm after magnetic midnight and with an eastward drift imposed. Black auroras show a significant reduction in optical brightness compared to the surrounding diffuse aurora, and can appear as slow-moving arcs or rapidly-moving patches and arc segments. We report, for the first time, an even more elusive small-scale optical structure that has always been observed occurring paired with ∼ 10% of black aurora patches. A patch or arc segment of enhanced luminosity, distinctly brighter than the diffuse background, which we name the anti-black aurora, may appear adjacent to the black aurora. The anti-black aurora is of similar shape and size, and always moves in parallel to the drifting black aurora, although it may suddenly switch sides for no apparent reason. The paired phenomenon always drifts with the same average speed in an easterly direction. From the first dual-wavelength (427.8 nm and 844.6 nm) optical observations of the phenomenon recorded on 12 March 2016 outside Tromsø Norway, we show that the anti-black and black auroras have a higher and lower mean energy, respectively, of the precipitating electrons compared to the diffuse background

A space between two worlds: St. Petersburg in the early eighteenth century

In May 1703, Tsar Peter I of Russia is alleged to have led a small military foray to the Baltic coastline, near the mouth of the river Neva. Accounts of this occasion, both contemporary and retrospective, vary considerably on the precise chronology of the decision-making process and the question of whether the tsar himself was actually present. Regardless of the precise details, the area was claimed (or, some argue, reclaimed) in the name of Russia and plans were made to build a fortress in order to consolidate the Russian presence. This foundation and the associated myths, which have been explored by many writers and historians over the intervening centuries, feature in most discussions of St. Petersburg’s history. One such myth, which presents Peter creating his new city out of nothing, in a wilderness, was essentially poetic license on the part of later writers such as Vasilii Trediakovskii and Aleksandr Pushkin. In fact, the area was the site of a Swedish fortress known as “Nienschants,” the town of Nien, with a population of around four thousand, and a number of smaller settlements nearby that existed before the city was founded. Indeed, given the paucity of usable stone in the region, the ruins of the old fortress likely provided material used in the initial stage of St. Petersburg’s construction, particularly in the foundations of buildings

Contemporary Presentation and Management of Valvular Heart Disease The EURObservational Research Programme Valvular Heart Disease II Survey

International audienceBackground: Valvular heart disease (VHD) is an important cause of mortality and morbidity and has been subject to important changes in management. The VHD II survey was designed by the EURObservational Research Programme of the European Society of Cardiology to analyze actual management of VHD and to compare practice with guidelines. Methods: Patients with severe native VHD or previous valvular intervention were enrolled prospectively across 28 countries over a 3-month period in 2017. Indications for intervention were considered concordant if the intervention was performed or scheduled in symptomatic patients, corresponding to Class I recommendations specified in the 2012 European Society of Cardiology and in the 2014 American Heart Association/American College of Cardiology VHD guidelines. Results: A total of 7247 patients (4483 hospitalized, 2764 outpatients) were included in 222 centers. Median age was 71 years (interquartile range, 62-80 years); 1917 patients (26.5%) were >= 80 years; and 3416 were female (47.1%). Severe native VHD was present in 5219 patients (72.0%): aortic stenosis in 2152 (41.2% of native VHD), aortic regurgitation in 279 (5.3%), mitral stenosis in 234 (4.5%), mitral regurgitation in 1114 (21.3%; primary in 746 and secondary in 368), multiple left-sided VHD in 1297 (24.9%), and right-sided VHD in 143 (2.7%). Two thousand twenty-eight patients (28.0%) had undergone previous valvular intervention. Intervention was performed in 37.0% and scheduled in 26.8% of patients with native VHD. The decision for intervention was concordant with Class I recommendations in symptomatic patients with severe single left-sided native VHD in 79.4% (95% CI, 77.1-81.6) for aortic stenosis, 77.6% (95% CI, 69.9-84.0) for aortic regurgitation, 68.5% (95% CI, 60.8-75.4) for mitral stenosis, and 71.0% (95% CI, 66.4-75.3) for primary mitral regurgitation. Valvular interventions were performed in 2150 patients during the survey; of them, 47.8% of patients with single left-sided native VHD were in New York Heart Association class III or IV. Transcatheter procedures were performed in 38.7% of patients with aortic stenosis and 16.7% of those with mitral regurgitation. Conclusions: Despite good concordance between Class I recommendations and practice in patients with aortic VHD, the suboptimal number in mitral VHD and late referral for valvular interventions suggest the need to improve further guideline implementation