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Data of magnetic storms and term-day observations from the Prague-Clementinum observatory (1839-1849)
No full textWe provide in digital form unique data observed at Prague-Clementinum in years 1839-1849. The data were obtained by digitising and processing the original old records published in the yearbooks of this historical observatory. The data contain two categories of high cadence observations of magnetic declination and horizontal intensity. The first of these categories captures 73 magnetic storms with their magnitude being of at least a moderate level. The second category is the dense observations during the days that had been agreed for joint measurements by the observatories organised in the Göttingen Magnetic Union (GMU), these measurements being known as term-day observations. Whereas four terms per year were set by GMU, many observatories agreed to carry out additional observations in the eight remaining months. The term-day observations also continued being performed for several years after the end of the GMU activities in 1841. Data of 120 term-days from January 1840 to December 1849 are published. The observations started at 10 p.m. of Göttingen Mean Time and lasted 24 hours. The interval between observations was 5 minutes (in April, June and July 1842 exceptionally 6 minutes). All time data were transformed into UT, based on the longitude of the Göttingen observatory, which was 9.950°. The time shift is thus 39'48''. The date in the file name of magnetic storm indicates the start day of the event, whereas the date in the term-day file name indicates the second day which involves substantial part of the observations (22 out of 24 hours)
Některá témata diferenciání a zobecněné geometrie s aplikacemi ve fyzice.
Get PDFDifferential geometry plays a prominent role in many areas of modern theoretical physics, ranging from electromagnetism and Yang-Mills to Einstein's general theory of relativity. It became a standard tool to investigate both the local and global properties of classical and quantum physical systems. Generalized geometry, as it emerged from string theory and has been first formulated mathematically by Hitchin and his students, proves to be a valuable tool for further study of quantum field theory and strings. We rigorously introduce all essential concepts of differential geometry, which are then crucial to build a basic framework of the generalized tangent bundle. 1Mathematical Institute of Charles UniversityMatematický ústav UKMatematicko-fyzikální fakultaFaculty of Mathematics and Physic
Courant algebroids and string low energy effective actions
No full textCette thèse est consacrée à l'application des méthodes de la géométrie de Poisson dans le contexte de la théorie des cordes, notamment pour étudier la limite d'énergie basse et les dualités de cette dernière. Les résultats contenus dans la thèse sont les suivants: - Reformulation des notions de tenseur de Ricci et de courbure scalaire généralisées aux algébroïdes de Courant. - Dérivation de ces tenseurs de courbure à partir de la variation d'une action naturelle. - Preuve de la compatibilité de la T-dualité de Poisson-Lie avec les transformations infinitésimales du groupe de renormalisation à une boucle, dans la configuration générale. - Preuve de la compatibilité de la T-dualité de Poisson-Lie avec la partie bosonique des équations d'arrière-plan pour les 5 théories des supercordes. - Découverte des nouvelles classes de solutions d'équations de supergravité modifiées sur des espaces symétriques
The intense magnetic storm of March 1918 as recorded by observatory Ógyalla (present day Hurbanovo)
Get PDFVyšší struktury v matematické fyzice
No full textVyšší struktury nabízejí přirozený jazyk pro popis teorie kalibračních polí. Tato práce poskytuje pedagogický úvod do nezbytného matematického pozadí, včetně graduované geometrie, teorie kategorií a vyšších struktur. Motivujeme a podrobně popisujeme proces kvantování, konkrétně Faddeev-Popovův trik, formalismus Becchi-Rouet-Stora-Tyutina a Batalin-Vilkovského formalismus. Prostřednictvím tohoto přístupu odhalujeme algebraic- kou strukturu teorií polí, kterou ilustrujeme na příkladech, jako je Chern-Simonsova a Yang-Millsova polní teorie.Higher structures offer a natural framework for the description of gauge field theories. This work provides a pedagogical introduction to the necessary mathematical background, including graded geometry, category theory, and higher structures. We motivate and detail the quantization process, namely the Faddeev-Popov trick, the Becchi-Rouet-Stora- Tyutin formalism, and the Batalin-Vilkovisky formalism. Through this approach, we uncover the algebraic structure of field theories, which we illustrate with examples such as Chern-Simons and Yang-Mills theories.Mathematical Institute of Charles UniversityMatematický ústav UKMatematicko-fyzikální fakultaFaculty of Mathematics and Physic
Higher Structures in Mathematical Physics
No full textHigher structures offer a natural framework for the description of gauge field theories. This work provides a pedagogical introduction to the necessary mathematical background, including graded geometry, category theory, and higher structures. We motivate and detail the quantization process, namely the Faddeev-Popov trick, the Becchi-Rouet-Stora- Tyutin formalism, and the Batalin-Vilkovisky formalism. Through this approach, we uncover the algebraic structure of field theories, which we illustrate with examples such as Chern-Simons and Yang-Mills theories
Exceptional algebroids and type IIA superstrings
No full textWe study exceptional algebroids in the context of warped compactifications of type IIA string theory down to dimensions, with . In contrast to the M-theory and type IIB case, the relevant algebroids are no longer exact, and their locali moduli space is no longer trivial, but has distinct points. This relates to two possible scalar deformations of the IIA theory. The proof of the local classification shows that, in addition to these scalar deformations, one can twist the bracket using a pair of -forms, a -form, a -form, and a -form. Furthermore, we use the analysis to translate the classification of Leibniz parallelisable spaces (corresponding to maximally supersymmetric consistent truncations) into a tractable algebraic problem. We finish with a discussion of the Poisson-Lie U-duality and examples given by tori and spheres in , , and dimensions.18 pages, accepted version, added Conclusions, small change
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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