L'Europe nouvelle vue de Prague

Czech View of the New Europe by Alexandr Ort The upheavals experienced by Czechoslovakia in 1989 brought many internal policy problems but also had a significant impact on foreign policy. Since the founding of the Czech State in 1918, the government has always sought to secure its independence by a foreign policy aimed to preserve peace in Europe. In divided Europe, it found itself committed to an Eastern bloc dominated by the USSR. After the events of 1968, its foreign policy was obliged to follow Soviet directives. In 1989, with a new government installed an a new president elected, a whole range of new options became possible. The Czechs and the Slovaks consider the location of the permanent secretariat of the CSCE in Prague as recognition of their country's significant role in this new organisation particularly in its human rights dimension.Les bouleversements qu'a connus la Tchécoslovaquie en 1989 ont suscité nombre de problèmes dans la politique intérieure du pays. Ils ne pouvaient pas ne pas influencer également sa politique extérieure. Depuis la fondation de l'Etat en 1918, le gouvernement tchécoslovaque a toujours cherché à garantir l'indépendance et la sécurité de la République par son attachement à un système de sécurité qui puisse assurer la paix sur le continent européen. Dans une Europe coupée en deux, le pays fut inclus irrévocablement dans la partie orientale dominée par l'URSS et, après 1968, la Tchécoslovaquie « normalisée » s'aligna docilement sur la politique étrangère soviétique. En 1989, le nouveau gouvernement étant formé et un nouveau président élu, il fallait adopter une politique nouvelle dans le pays, y compris pour ses relations extérieures. La décision de créer un secrétariat permanent de la CSCE, siégeant à Prague, est interprétée par les Tchèques et les Slovaques comme une reconnaissance de la participation active de leur pays à la Conférence sur la sécurité et la coopération en Europe, notamment la dimension humaine du processus.Ort. L'Europe nouvelle vue de Prague. In: Politique étrangère, n°1 - 1991 - 56ᵉannée. pp. 149-156

Tomorrow's Europe : the views of those concerned

845 p., ref. bib. : 37 p

Coronal Heating as Determined by the Solar Flare Frequency Distribution Obtained by Aggregating Case Studies

Flare frequency distributions represent a key approach to addressing one of the largest problems in solar and stellar physics: determining the mechanism that counter-intuitively heats coronae to temperatures that are orders of magnitude hotter than the corresponding photospheres. It is widely accepted that the magnetic field is responsible for the heating, but there are two competing mechanisms that could explain it: nanoflares or Alfv\'en waves. To date, neither can be directly observed. Nanoflares are, by definition, extremely small, but their aggregate energy release could represent a substantial heating mechanism, presuming they are sufficiently abundant. One way to test this presumption is via the flare frequency distribution, which describes how often flares of various energies occur. If the slope of the power law fitting the flare frequency distribution is above a critical threshold, $\alpha=2$ as established in prior literature, then there should be a sufficient abundance of nanoflares to explain coronal heating. We performed $>$600 case studies of solar flares, made possible by an unprecedented number of data analysts via three semesters of an undergraduate physics laboratory course. This allowed us to include two crucial, but nontrivial, analysis methods: pre-flare baseline subtraction and computation of the flare energy, which requires determining flare start and stop times. We aggregated the results of these analyses into a statistical study to determine that $\alpha = 1.63 \pm 0.03$. This is below the critical threshold, suggesting that Alfv\'en waves are an important driver of coronal heating.Comment: 1,002 authors, 14 pages, 4 figures, 3 tables, published by The Astrophysical Journal on 2023-05-09, volume 948, page 7