Refine
Year of publication
Document Type
- Article (30512)
- Part of Periodical (11870)
- Book (8231)
- Doctoral Thesis (5594)
- Part of a Book (3869)
- Working Paper (3371)
- Review (2921)
- Contribution to a Periodical (2278)
- Preprint (1809)
- Report (1561)
Language
- German (42692)
- English (28429)
- French (1071)
- Portuguese (843)
- Multiple languages (312)
- Spanish (309)
- Croatian (302)
- Italian (197)
- mis (174)
- Turkish (168)
Keywords
- Deutsch (1082)
- Literatur (862)
- taxonomy (738)
- Deutschland (551)
- Rezension (511)
- new species (438)
- Rezeption (349)
- Frankfurt <Main> / Universität (341)
- Übersetzung (311)
- Geschichte (300)
Institute
- Medizin (7371)
- Präsidium (5082)
- Physik (4114)
- Extern (2742)
- Wirtschaftswissenschaften (2657)
- Gesellschaftswissenschaften (2366)
- Biowissenschaften (2111)
- Biochemie und Chemie (1950)
- Center for Financial Studies (CFS) (1609)
- Informatik (1577)
In tutte le sue diverse declinazioni, il dissenso nei riguardi della propria patria costituisce un motivo centrale e ricorrente nella cultura austriaca del Novecento. Come in una sorta di contagio il carattere distruttivo, soprattutto nel Secondo dopoguerra, si è diffuso – e continua a diffondersi – ad ampio raggio: esempi emblematici sono offerti da Peter Handke, con i suoi "insulti all'Austria" urlati dall'esilio francese, dalla prosa sofferta di Ingeborg Bachmann, che ha riparato a Roma, dalla scrittura caustica del Premio Nobel Elfriede Jelinek, o da quella estrema di Werner Schwab. Ma anche da autori meno noti, come Anna Mitgutsch, che, dagli Stati Uniti, non manca di esternare la sua avversione nei confronti del paese d'origine, o dai toni aspri dello scrittore Robert Menasse. Lo steso vale per il campo cinematografi co, con il cinema a tinte forti di Ulrich Seidl. Una passion durevole, quella degli austriaci per i toni antipatriottici, una tradizione che vanta come anticipatore il sacro nome del grande polemista Karl Kraus, o forse, ancor prima, affonda le sue radici nel teatro di Raimund Nestroy. Se l'ostilità per l'Austria sembra un Leitmotiv della grande retorica austriaca, Thomas Bernhard (1931-1989) può essere a giusto titolo considerate non solo come il legittimo erede di questa grande tradizione, ma anche come il suo massimo rappresentante. Ereditare signifi ca infatti fare i conti in modo cinico e rischioso con l'orizzonte vitale e culturale a cui si appartiene e che ci appartiene. Autore diffi cile, maniacale, irriverente ed eccessivo, Bernhard si è imposto all'attenzione del grande pubblico per la sua appassionata denuncia dell'universo austriaco, e della sua atmosfera piccolo-borghese, conformista, ottusamente fi loclericale. I suoi frequenti interventi pubblici – ora raccolti e pubblicati con il titolo Meine Preise – presentano come unico obiettivo la provocazione, e di fatto hanno suscitato scandali, polemiche. Un esempio per tutti è il discorso tenuto nel 1967 per il Conferimento del "Premio Nazionale Austriaco per la Letteratura": "Noi siamo austriaci, siamo apatici, siamo la vita intesa come ignobile disinteresse nei confronti della vita, siamo, nel processo naturale, la megalomania intesa come futuro". Un testo scritto con un inchiostro che è succo di nervi. Ma questa è solo una delle tante puntate che vedono Bernhard in polemica con i suoi connazionali, e che hanno contribuito a designarlo come un Nestbeschmutzer. È questa una visione decisamente riduttiva. Lo humour nero bernhardiano, che di certo ci ha regalato pagine irresistibili, nasce da un sentimento di amore e odio nei confronti dell'Austria. Per dirla in altri termini, è sintomo non di una nevrastenica insofferenza (di cui poco ci importerebbe), quanto piuttosto di una Unheimlichkeit, di un sofferto legame con l'origine. Su questo punto, per ora solo accennato, avrò occasione di tornare.
In un'intervista rilasciata in piena maturità a ricordo degli anni di gioventù, Bloch concentra la sua attenzione sulle rilessioni antimilitaristiche contenute in 'Spirito dell'utopia' (1918 e 1923). soprattutto riformula quella questione che – proposta con veemenza nella Introduzione (dal titolo Intenzione) del suo libro – attraversa come un ilo sotterraneo tutta la sua produzione giovanile: "dove deve essere rintracciata l'origine di quella cecità che ha portato al crimine della guerra? perché il popolo dei poeti e dei pensatori ha imboccato il vicolo cieco del primo conlitto mondiale?".
La vis polemica di Bloch nei confronti dello storico colpo di tuono emerge dai passi iniziali di 'Spirito dell’utopia', uno studio che – come segnala l'"avvertenza" del 1936 – è stato "sviscerato e realizzato di note contro la guerra". È soprattutto a un intenso brano della "Intenzione" che bloch affida la sua denuncia della barbarie della prima conflagrazione bellica, inquadrandola in uno 'Zeitgeist' di generale immiserimento economico e morale.
Die vorliegende Arbeit behandelt das Forschungsthema der Entstehung des flüssigen Eisenkerns im Zentrum unseres Planeten. Dieses bislang wenig verstandene Gebiet ist reich an Fragestellungen, sowohl für Experimentatoren als auch für die Geodynamik. Es gibt sehr viele Arbeiten, die den Bildungsprozess experimentell untersuchen, jedoch wurde in den letzten Jahren die numerische Untersuchung in diesem Gebiet kaum vorangetrieben. Der experimentelle Teil der Arbeit stellt sich hierbei der aktuellen Frage nach der Perkolationsschwelle
1 von Eisenschmelze in der Silikatmatrix der Protoerde, während numerisch die Effekte von Potenzgesetzkriechen, Dissipation und Schmelzsegregation beim Absinken eines Eisendiapirs nach Ausbildung eines ersten flachen Magmaozeans in der Protoerde behandelt werden. Die genauen Fragestellungen könnnen dabei im letzten Abschnitt der Einleitung gefunden werden.
Sondierungsstudie im Auftrag des Bundesministeriums für Bildung und Forschung: Die jüngste Finanzkrise und die darauf folgende Staatsschuldenkrise hat sowohl wirtschaftlich als auch gesellschaftlich tiefgreifende Spuren hinterlassen. Dabei wurden auch sehr deutliche Lücken in der Forschung offenbar. Ziel dieser Studie ist es, aufbauend auf dem aktuellen Forschungsstand weiteren Forschungsbedarf in den wesentlich mit Finanzkrisen verbundenen Bereichen aufzuzeigen. Es werden fünf Forschungsbereiche mit jeweiligen Unterthemen vorgeschlagen. Diese fünf Forschungsbereiche gehen unmittelbar aus der Struktur und den Mechanismen der Finanz- und Staatsschuldenkrise hervor. Dabei wird besonderes Augenmerk auf die wirtschafts- und regulierungspolitische Relevanz der Themen sowie dem Umstand getragen, dass die Beantwortung vieler der Fragen interdisziplinäre Zusammenarbeit erfordert.
Finanzkrisen sind inherent mit dem Bankenmodell verbunden. Aufgrund von Verbindungen der Banken untereinander können Probleme einzelner Institute auf andere Institute übertragen werden. Diese systemischen Risiken können das gesamte Finanzsystem destabilisieren. Das Finanzsystem nimmt durch die Kreditvergabe und Bereitstellung von Transaktionssystemen eine herausragende Stellung in einer Volkswirtschaft ein, wodurch stabilisierende Eingriffe der Politik notwendig werden können. Eingriffe zur Wiederherstellung von Stabilität können sehr kostspielig sein und, wie aktuell eindrucksvoll belegt, die stabilisierenden Staaten selbst destabilisieren. Die alternativen Eingriffe vorab betreffen neben der Geldpolitik vor allem regulatorische Eingriffe. Im besonderen sind die Corporate Governance von Finanzinstituten und die Informationsbereitstellung bzw. Transparenz innerhalb des Finanzsektors von Bedeutung. In den vergangen Jahren wuchs vor dem Hintergrund von Regulierung zudem ein paralleles Schattenbankensystems heran, das in seiner Bedeutung dem traditionellen Bankensystem nur unwesentlich nachsteht.
Zwar sind die groben Zusammenhänge und Auswirkungen in den einzelnen Bereichen bekannt, jedoch ist für ein tiefgreifendes Verständnis als Grundlage zur Vermeidung bzw. Eindämmung zukünftiger Krisen sowie zur Folgenabschätzung von Regulierung weitere Forschung unabdingbar.
In the past century, scientists have realized that venoms are a source of a number of natural substances presenting a wide range of pharmacological properties and often displaying a high specificity for their targets. Thus, the field of toxinology came into being, which is defined as the study of toxic substances of biological origin. Toxins are found in a wide variety of animals, including fish, cone snails, scorpions, snakes, and even some mammals. To be classified as venom, these must contain substances, i.e. toxins, which disturb physiological processes and must be deliberately delivered to the target animal. Snakes have evolved one of the most sophisticated mechanisms for venom delivery. Envenomation by snakebite can induce and inhibit aggregation/agglutination of platelets as well as inhibit/activate hemostasis, but also disrupt other physiological functions via neurotoxins and angioneurin growth factors. Snake venoms contain a substantial amount of C-type lectin-related proteins (CLRPs) which are known to function, notably, as integrin inhibitors. CLRPs are heterodimers composed of homologous α and β subunits which can assemble either covalently or noncovalently to oligomers, resulting in αβ, (αβ)2 and (αβ)4 structures. Some of the main targets of CLRPs are membrane receptors, coagulation factors, and proteins essential to hemostasis. The platelet collagen receptors GPVI and α2β1 integrin as well as the von Willebrand factor receptor GPIb play important roles in platelet activation and aggregation and are considered main targets of antithrombotic drugs. In this thesis, the integrin α2β1 is particularly considered as it is the sole collagen-binding integrin on platelets. Reduced expression of this platelet receptor results in dysfunction of platelet responses. Equivalently, overexpression of α2β1 integrin results in an increased risk of thrombosis. As a result, selective inhibitors of the collagen-α2β1 interaction could give rise to effective antithrombotic drugs. Integrins are large receptors which mediate cell-cell contacts and the binding of cells to the extracellular matrix (ECM). Therefore, they play a role in physiological processes, e.g. hemostasis and immunity, as well as in pathological processes, e.g. tumor angiogenesis and atherosclerosis. 18 α and 8 β integrin subunits, with nine α subunits containing an additional A domain, associate non-covalently to form 24 heterodimers with distinct binding specificities. Integrin collagen receptors are a subclass of four receptors which all utilize the β1 subunit. The α2β1 integrin is a collagen-binding receptor expressed not only on platelets, but also on endothelial and epithelial cells. Consequently, this integrin is also essential for cell adhesion and migration playing a role in angiogenesis as well as tumor metastasis. To date, there are five known antagonists of α2β1 integrin: EMS16, rhodocetin, vixapatin, and most recently rhinocetin and flavocetin-A. The first four have been shown to be specific for the integrin α2A domain, the major collagen-binding domain. All these antagonists are CLRPs and present new leads for drug design. In the past few years, many insights into the structure and function of rhodocetin were obtained. Monoclonal antibodies proved to be advantageous in disclosing this information, making them not only useful as therapeutic agents, but also as tools for protein characterization. The venom of the Vipera palaestinae snake was recently shown to contain an α2β1 integrin inhibitor, which prevented the integrin from binding collagen. This inhibitor, called vixapatin, was the initial focus of this dissertation. Vixapatin’s interaction with the α2β1 integrin needed further characterization on a molecular and cellular level to assess its medical potential and monoclonal antibodies were to be used as a tool. Originally, vixapatin had been isolated by reversed-phase high-performance liquid chromatography. To avoid the stringency of this method, for this study, it was replaced with gentler chromatographic methods. First, the α2β1 integrin inhibitor was isolated from the crude snake venom with affinity chromatography using the α2A domain as bait, establishing a method to quickly screen venoms for α2β1-binding proteins which affect the collagenintegrin interaction. The applicability of this method to other snake venoms was shown by isolating an α2A domain-specific toxin from the venom of Trimeresurus flavoviridis. To allow further characterization of both these toxins, gel filtration and ion exchange chromatography were employed to purify the protein without the α2A domain. These classical protein purification methods resulted in similar separation patterns of both the V. palaestinae and T. flavoviridis venom proteins. Purified proteins exhibiting the potential of inhibiting integrinbinding to collagen were analyzed by two-dimensional gel electrophoresis. Both VP-i and flavocetin-A, the integrin inhibitors from V. palaestinae and T. flavoviridis, respectively, were shown to have more complex structures than was evident from the purification. Each consisted of four low-molecular-weight proteins which assembled into two bands (for VP-i) or one single band (for flavocetin-A) under non-reducing conditions. Mass spectrometry analyses revealed VP-i to belong to the family of CLRPs, just like vixapatin does. However, these two proteins differed in their primary sequences and only showed homology to one another. The toxin purified from T. flavoviridis revealed this toxin to be flavocetin-A, a heterodimeric CLRP which had so far only been shown to have GPIb-binding activity. At the time of flavocetin-A’s purification, flavocetin-B was co-purified; flavocetin-B consists of the same two α and β subunits, plus an additional γ subunit. As no sequence information is known to date for the γ subunit, it may be one of the additional proteins purified here, along with an additional δ subunit. Therefore, the toxin isolated here may actually consist of four different subunits forming a tetramer of two different heterodimers, generating an (αβ)2(γδ)2 structure. This proposed (αβ)2(γδ)2 flavocetin-A structure has binding sites for both α2β1 integrin and GPIb, with no sterical overlap, as shown by affinity chromatography using the α2A domain and the extracellular domain of the GPIb receptor. The potential of VP-i and flavocetin-A to inhibit integrin-binding to type I collagen was shown during purification: Both toxins efficiently bind to the integrin α2A domain; also, VP-i and vixapatin bind to the A domain with the same affinity. Surface plasmon resonance showed the interaction of flavocetin-A with the α2β1 integrin to be extremely strong and association to be very fast. Furthermore, both toxins were shown to inhibit binding of the wildtype integrin to collagen: VP-i and flavocetin-A acted antagonistically on cell adhesion and cell migration. Initially, the interaction between VP-i and α2β1 integrin was to be further characterized with the help of monoclonal antibodies. However, this proved problematic, the procedure requiring various optimizations. Although, after expert consultation, some monoclonal antibodies could be obtained, the cells were extremely sensitive and gave unsatisfactory results when tested as detection tools in Western blot and immunoassays. Concluding, two novel α2β1 integrin inhibitors were discovered: VP-i and flavocetin-A, which were purified using the same procedure and which have similar functions. Both are Ctype lectin-related proteins which effectively inhibit cell adhesion and migration. This underlines that nature has instrumentalized CLRPs to specifically inhibit α2β1 integrin. Further characterization of VP-i and flavocetin-A will be able to provide leads for future drug development.
Sovereign bond risk premiums
(2013)
Credit risk has become an important factor driving government bond returns. We therefore introduce an asset pricing model which exploits information contained in both forward interest rates and forward CDS spreads. Our empirical analysis covers euro-zone countries with German government bonds as credit risk-free assets. We construct a market factor from the first three principal components of the German forward curve as well as a common and a country-specific credit factor from the principal components of the forward CDS curves. We find that predictability of risk premiums of sovereign euro-zone bonds improves substantially if the market factor is augmented by a common and an orthogonal country-specific credit factor. While the common credit factor is significant for most countries in the sample, the country-specific factor is significant mainly for peripheral euro-zone countries. Finally, we find that during the current crisis period, market and credit risk premiums of government bonds are negative over long subintervals, a finding that we attribute to the presence of financial repression in euro-zone countries.
This paper takes a novel approach to estimating bankruptcy costs by inference from market prices of equity and put options using a dynamic structural model of capital structure. This approach avoids the selection bias of looking at firms in or near default and therefore permits theories of ex ante capital structure determination to be tested. We identify significant cross sectional variation in bankruptcy costs across industries and relate these to specific firm characteristics. We find that asset volatility and growth options have significant positive impacts, while tangibility and size have negative impacts. Our bankruptcy cost variable estimate significantly negatively impacts leverage ratios. This negative impact is in addition to that of other firm characteristics such as asset intangibility and asset volatility. The results provide strong support for the tradeoff theory of capital structure.