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Homogeneous Ricci flows and the Dynamical Alekseevskii Conjecture
No full textDiese Dissertation befasst sich mit der Ricci-Fluss-Gleichung in der riemannischen
Geometrie. Das Hauptziel ist es, unser Verständnis des langfristigen Verhaltens von
Ricci-Fluss-Lösungen mit homogenen Anfangsmetriken zu vertiefen. Konkret wird die
Dynamische Alekseevskii-Vermutung behandelt, die besagt, dass der universelle Überzug
einer unsterblichen homogenen Ricci-Fluss-Lösung zusammenziehbar ist. Zunächst stellen
wir ein allgemeines strukturelles Ergebnis für die Isometriengruppe einer homogenen
Mannigfaltigkeit auf, die eine unsterbliche Ricci-Fluss-Lösung zulässt, nämlich dass diese
keine einfache normale kompakte Untergruppe enthält. Danach zeigen wir, dass die
Vermutung für zwei spezielle Mengen homogener Anfangsmetriken gilt: die
awesome-Metriken und die awesome-Polarmetriken. Das Testen der Vermutung in diesen
Fällen ist von Interesse, weil sie Metriken mit negativer Ricci-Krümmung enthalten und
daher komplexere Argumente erfordern, um die anfänglichen Krümmungsschätzungen zu
verbessern, was wiederum unser Verständnis des allgemeinen Falls erweitern könnte. Im
Fall der awesome-Metriken führen die gewonnenen geometrischen Schätzungen zu einer
genaueren Beschreibung der asymptotischen Geometrien der Lösungen, sowohl im
unsterblichen als auch im nicht unsterblichen Fall.This dissertation deals with the Ricci flow equation in Riemannian geometry. The main goal
is to deepen our understanding of the long-time behavior of Ricci flow solutions with
homogeneous initial metrics. Specifically, it addresses the Dynamical Alekseevskii
Conjecture, which states that the universal covering of an immortal homogeneous Ricci flow
solution is contractible. First, we establish a general structural result for the isometry group
of a homogeneous manifold admitting an immortal Ricci flow solution, namely that it does
not contain a simple normal compact subgroup. We then show that the conjecture holds for
two special sets of homogeneous initial metrics: the awesome metrics and the awesome
polar metrics. Testing the conjecture in these cases is of interest because they include
metrics with negative Ricci curvature and therefore require more involved arguments to
improve the initial curvature estimates, which in turn could expand our understanding of the
general case. In the case of awesome metrics, the obtained geometric estimates lead to a
more accurate description of the asymptotic geometries of the solutions, both in the
immortal and non-immortal cases
Liberal Corona Policy
No full textEs wird ein liberaler Ansatz zum Umgang mit der aktuellen Corona-Pandemie vorgestellt, der mehr auf individuellen Entscheidungen und Eigenverantwortung setzt als auf staatliche Vorgaben und Zwang, die weder besonders effektiv noch effizient sind. Die Anwendung dieses Ansatzes wird für zahlreiche Unterthemen skizziert und diskutiert, es werden allerdings auch mögliche Grenzen benannt.A liberal approach to dealing with the current coronavirus pandemic is presented, which relies more on individual decisions and personal responsibility than on state requirements and coercion that are neither particularly effective nor efficient. The application of this approach is outlined and discussed for numerous sub-topics, but possible limits are also named
Multi-chiral materials comprising metallosupramolecular and covalent helical polymers containing five axial motifs within a helix
No full textSupramolecular and covalent polymers share multiple structural effects such as communication mechanisms among monomer repeating units, which are related to their axial helical structure. Herein, a unique multi-helical material combining information from both metallosupramolecular and covalent helical polymers is presented. In this system, the helical structure described by the poly(acetylene) (PA) backbone ('cis-cisoidal', 'cis-transoidal') guides the pendant groups in a fashion where a tilting degree emerges between a pendant and the adjacent ones. As a result, a multi-chiral material is formed comprising four or five axial motifs when the polyene skeleton adopts either a 'cis-transoidal' or 'cis-cisoidal' configuration: the two coaxial helices—internal and external—and the two or three chiral axial motifs described by the bispyridyldichlorido PtII complex array. These results show that complex multi-chiral materials can be obtained by polymerizing appropriate monomers that combine both point chirality and the ability to generate chiral supramolecular assemblies
Gramática da Lingua Geral do Brazil:Manuscrito anônimo de 1750, Universidade de Coimbra No. 69. Transcrição, edição comentada e análise linguística
No full textKommentierte Erstausgabe einer anonymen Grammatik der "brasilianischen Sprache" des 17. oder 18. Jhs. Das Manuskript der einzigen bekannten, wahrscheinlich franziskanischen, Grammatik der als Verkehrssprache dienenden "Língua brasílica", indigenen Ursprungs, wird in diplomatischer Transkription erstmals veröffentlicht, versehen mit zahlreichen linguistischen und sprachhistorischen Kommentaren. Das der "Língua Geral do Brazil" zugrundeliegende Tupinambá wird dadurch strukturell verändert, dass es von nicht-indigenen Siedlern und Missionaren übernommen wird und so über die gesamte Kolonialzeit hin zur "Língua geral" oder "Língua brasílica" wird. Es wurde an der gesamten Küste Brasiliens und in Amazonien gesprochen und lebt noch heute in Rückzugsgebieten fort.
In diesem Buch werden vor allem die durch den Kontakt mit dem Portugiesischen erfolgten sprachlichen Veränderungen, soweit sie in der Grammatik dokumentiert sind, herausgearbeitet. Beschreibungssprache ist Portugiesisch.Here is published for the first time an anonymous Portuguese manscript, which contains the only grammar of Amazonian General Language we know. Not only the author, probably a Franciscan missionary, but also time and place of composition are unknown. It only can be presumed that it was written at the end of the 17th or during the first decades of the 18th century. Manuscript 69 of the University Library of Coimbra (Portugal), which is edited here, is a copy of a lost original. It includes the grammar and a dictionary of the same language, which is still unpublished.
The transcription of the grammar is accompanied by a large number of linguistic comments, all in Portuguese, preceded by a philological and a linguistic introduction as well. It is followed by a more detailed linguistic study about the role Amazonian General Language played in the history of language change. A sketch of a historical phonology and grammar is included
What Is the Survivorship of Megaprosthetic Reconstruction Following the Resection of Renal Cell Carcinoma Long Bone Metastases and What Are the Potential Risk Factors for a Prosthetic Complication?
No full textBackground: Long bone metastases are common in patients with metastatic renal cell carcinoma (RCC). One potential surgical treatment option is resection and megaprosthetic reconstruction. However, implant complications and survival are poorly understood. This study analyzes patient and implant survival as well as associated risk factors. Methods: This is a retrospective study from a single academic center, analyzing 86 patients that underwent resection and megaprosthetic reconstruction performed between 1993 and 2017. The most common location of megaprosthetic reconstruction was the proximal femur (PFR) in 38% (33 of 86) of patients. We calculated overall patient survival and associated risk factors using the Kaplan–Meier method and implant survivorship using a competing risk analysis. Results: A total of 73% (63/86) of patients died of their disease after a median of 19 (IQR 9–37) months following surgery, and a median of 71 (IQR 31–132) months after the initial diagnosis of RCC. The overall survival probability was 29% (95% CI 18–40%) five years after surgery. The five-year risk of revision surgery (within a competing risk framework) was 18% (95% CI 11–28). A total of 8% (7 of 86) of patients underwent an exchange of the implant itself. Patients with total bone replacements had a higher revision risk (SHR 19.46 (95% CI 6.9–54.9), p < 0.01). Furthermore, the revision risk was higher with increasing reconstruction length per mm (SHR 1.01 (95% CI 1.01–1.02), p = 0.03) and prolonged surgical time per minute (SHR: 1.01 (95% CI 1.0–1.02), p < 0.01). Local postoperative radiation treatment (RTX) was associated with an increased risk for revisions (SHR 2.59 (95% CI 0.96–6.95), p = 0.06). Conclusions: Modular megaprostheses demonstrated a fairly low risk of implant revision although postoperative radiation therapy and total bone replacements are associated with an increased risk
A Cell Biologist’s View on APOL1: What We Know and What We Still Need to Address
No full text'APOL1' is the most recent member of the 'APOL' gene family and is expressed exclusively in humans and a few higher primates. More than twenty years ago, it was discovered that APOL1 protects humans from infections by trypanosome subspecies that cause African sleeping sickness. Interestingly, by a co-evolutionary process between parasite and host, two APOL1 variants emerged, which, in addition to their trypanotoxic effects, are simultaneously associated with a significantly increased risk for various different kidney diseases, which are now summarized as APOL1-mediated kidney diseases (AMKDs). The aim of this review is to highlight and formulate key aspects of APOL1’s cell biologic features, including questions and unaddressed aspects. This perspective may contribute to a deeper understanding of APOL1-associated cytotoxicity as well as AMKDs
A matter of life and death. The Akkadian verb dâku and Tukultī-apil-Ešarra IV*'s war with Mukīn-zēri (731–727 BC)
No full textDiese Anmerkung untersucht die genauen Konnotationen des akkadischen Verbs daku "toten" und zeigt, dass seine gelegentliche Obersetzung mit dem nicht todlichen "besiegen" nach den derzeitigen Erkenntnissen ungerechtfertigt ist. Dies hat entscheidende Konsequenzen fur die assyrische Invasion Babyloniens ab 731 v. Chr. und erfordert eine neue Chronologie der Ereignisse der Invasion. Daraus lasst sich ableiten, dass sich die Regierungszeit des vorherigen babylonischen Konigs Mukin-zeri tatsachlich mit der van Tukulti-apil-Esarra IV*. uberschneidet (wie im Ptolemaischen Kanan angedeutet) und dass Mukin-zeri erst 727 v. Chr. bei einer Belagerung starb, nur wenige Monate vor
Tukulti-apil-Esarra IV*. selbst. Dies deutet darauf hin, dass die assyrische Besetzung Babyloniens van Anfang an chaotisch verlief und nicht erst, nachdem Marduk-apla-iddina (11.) 722 v. Chr. den Thran bestiegen hatte.This note investigates the precise connotations of the Akkadian verb daku 'to kill', demonstrating that its occasional translation as the non-lethal 'to defeat' is unwarranted according to present evidence. This has crucial consequences for the Assyrian invasion of Babylonia from 731 BC onwards, demanding a new chronology for the invasion's events. As a result, it can be shown that the preceeding Babylonian king Mukin-zeri's reign actually overlapped with that of Tukulti-apil-Esarra IV* (as implied by the Ptolemaic Canon), and that Mukin-zeri only died in 727 BC in a siege, a scarce few months before Tukulti-apil-Esarra IV* himself. This suggests that the Assyrian occupation of Babylonia was chaotic from the very outset, rather than only after Marduk-apla-iddina (11) took the throne in 722 BC
A tale of two scandals: scale shift and the inefficacy of crisis communication management in Olympic scandals
No full textIntroduction: Mega sporting events, such as the Olympic Games, provide niche sports with unique opportunities to attract public attention. However, scandals during these events can pose serious threats to these sports. In particular, if a sport scandal enables hostile stakeholders to achieve a scale shift, it becomes almost impossible for a niche sport organization to manage the scandal. Methods: The article employs a comparative research design that examines the trajectory of two scandals related to the German Olympic team that differ with regard to the occurrence of a scale shift. The first scandal involved a racist slur made by a German official during a cycling event; the second scandal was a case of animal cruelty during the modern pentathlon's equestrian event. Research relies on a mix of qualitative document analyses and quantitative analyses of the German Twitter discourse on both scandals. The analyses focus on the vulnerability to scandals, the potential for contentious politics, the scandal triggering events, the crisis communication, the reception, and the outcomes of both scandals.
Results and discussion: Our results show the detrimental impact of a scale shift on niche sports. The animal cruelty scandal put the future of the modern pentathlon at the Olympics at risk and triggered far-reaching reforms. The case supports the idea that a scale shift becomes more likely if there exists an effective collective action frame. In contrast, the German sports organizations effectively ended the racist slur scandal by imposing a limited sanction on the offender
