Refine
Year of publication
Document Type
- Article (30509)
- Part of Periodical (11892)
- Book (8260)
- Doctoral Thesis (5703)
- Part of a Book (3710)
- Working Paper (3386)
- Review (2878)
- Contribution to a Periodical (2338)
- Preprint (2053)
- Report (1544)
Language
- German (42389)
- English (29177)
- French (1067)
- Portuguese (723)
- Multiple languages (309)
- Croatian (302)
- Spanish (301)
- Italian (194)
- mis (174)
- Turkish (148)
Is part of the Bibliography
- no (75109) (remove)
Keywords
- Deutsch (1038)
- Literatur (807)
- taxonomy (760)
- Deutschland (543)
- Rezension (491)
- new species (449)
- Frankfurt <Main> / Universität (341)
- Rezeption (325)
- Geschichte (292)
- Linguistik (268)
Institute
- Medizin (7684)
- Präsidium (5156)
- Physik (4421)
- Wirtschaftswissenschaften (2688)
- Extern (2661)
- Gesellschaftswissenschaften (2372)
- Biowissenschaften (2180)
- Biochemie und Chemie (1972)
- Frankfurt Institute for Advanced Studies (FIAS) (1671)
- Center for Financial Studies (CFS) (1621)
A lot of interest has recently been paid to constraint-based definitions and extensions of Tree Adjoining Grammars (TAG). Examples are the so-called quasi-trees, D-Tree Grammars and Tree Description Grammars. The latter are grammars consisting of a set of formulars denoting trees. TDGs are derivation based where in each derivation step a conjunction is built of the old formular, a formular of the grammar and additional equivalences between node names of the two formulars. This formalism is more powerfull than TAGs. TDGs offer the advantages of MC-TAG and D-Tree Grammars for natural languages and they allow underspecification. However the problem is that TDGs might be unnecessarily powerfull for natural languages. To solve this problem, in this paper, I will propose a local TDGs, a restricted version of TDGs. Local TDGs still have the advantages of TDGs but they are semilinear and therefore more appropriate for natural languages. First, the notion of the semilinearity is defined. Then local TDGs are introduced, and, finally, semilinearity of local Tree Description Languages is proven.
Quantifizierung des pulmonal-arteriellen Drucks im Truncus pulmonalis des Schweins. Methode: Künstliche Induktion einer pulmonalen Hypertonie mittels Thromboxan A2 in verschiedenen Schweregraden. Quantifizierung des Blutflusses anhand magnetresonanztomographischer Flussmessung im T.p., hieraus Bestimmung des zeitlichen Flussprofils und Akzelerationszeit (AT). Korrelation der AT mit den simultan erhobenen Daten einer invasiven Druckmessung (Pulmonalis-Katheter).
This paper proposes a compositional semantics for lexicalized tree adjoining grammars (LTAG). Tree-local multicompnent derivations allow seperation of semantiv contribution of a lexical item into one component contributing to the predicate argument structure and second a component contributing to scope semantics. Based on this idea a syntx-semantics interface is presented where the compositional semantics depends only on the derivation structure. It is shown that the derivation structure allows an appropriate amount of underspecification. This is illustrated by investigating underspecified representations for quantifier scpoe ambiguities and related phenomena such as adjunct scope and island constraints.
A hierarchy of local TDGs
(1998)
Many recent variants of Tree Adoining Grammars (TAG) allow an underspecifiaction of the parent relation between nodes in a tree, i.e. they do not deal with fully specified trees as it is the case with TAGs.Such TAG variants are for example Description Tree Grammars (DTG), Unordered Vector Grammars with Dominance Links (UVG-DL), a definition of TAGs via so-called quasi trees and Tree Description Grammars (TDG. The last TAg variant, local TDG, is an extension of TAG generating Tree Descriptions. Local TDGs even allow an underspecification of the dominance relation between node names and thereby provide the possibility to generate underspecified representations for structural ambiguities such as quantifier scope ambiguities. This abstract deals with formal properties of local TDGs. A hierarchiy of local TDGs is established together with a pumping lemma for local TDGs of a certain rank.
We argue for incorporating the financial economics of market microstructure into the financial econometrics of asset return volatility estimation. In particular, we use market microstructure theory to derive the cross-correlation function between latent returns and market microstructure noise, which feature prominently in the recent volatility literature. The cross-correlation at zero displacement is typically negative, and cross-correlations at nonzero displacements are positive and decay geometrically. If market makers are sufficiently risk averse, however, the cross-correlation pattern is inverted. Our results are useful for assessing the validity of the frequently-assumed independence of latent price and microstructure noise, for explaining observed cross-correlation patterns, for predicting as-yet undiscovered patterns, and for making informed conjectures as to improved volatility estimation methods.
The future of securitization
(2008)
Securitization is a financial innovation that experiences a boom-bust cycle, as many other innovations before. This paper analyzes possible reasons for the breakdown of primary and secondary securitization markets, and argues that misaligned incentives along the value chain are the primary cause of the problems. The illiquidity of asset and interbank markets, in this view, is a market failure derived from ill-designed mechanisms of coordinating financial intermediaries and investors. Thus, illiquidity is closely related to the design of the financial chains. Our policy conclusions emphasize crisis prevention rather than crisis management, and the objective is to restore a “comprehensive incentive alignment”. The toe-hold for strengthening regulation is surprisingly small. First, we emphasize the importance of equity piece retention for the long-term quality of the underlying asset pool. As a consequence, equity piece allocation needs to be publicly known, alleviating market pricing. Second, on a micro level, accountability of managers can be improved by compensation packages aiming at long term incentives, and penalizing policies with destabilizing effects on financial markets. Third, on a macro level, increased transparency relating to effective risk transfer, risk-related management compensation, and credible measurement of rating performance stabilizes the valuation of financial assets and, hence, improves the solvency of financial intermediaries. Fourth, financial intermediaries, whose risk is opaque, may be subjected to higher capital requirements.
Proteorhodopsin (PR) originally isolated from uncultivated γ-Proteobacterium as a result of biodiversity screens, is highly abundant ocean wide. PR, a Type I retinal binding protein with 26% sequence identity, is a bacterial homologue of Bacteriorhodopsin (BR). The members within this family share about 78% of sequence identity and display a 40 nm difference in the absorption spectra. This property of the PR family members provides an excellent model system for understanding the mechanism of spectral tuning. Functionally PR is a photoactive proton pump and is suggested to exhibit a pH dependent vectorality of proton transfer. This raises questions about its potential role as pH dependent regulator. The abundance of PR in huge numbers within the cell, its widespread distribution ocean wide at different depths hints towards the involvement of PR in utilization of solar energy, energy metabolism and carbon recycling in the Sea. Contrary to BR, which is known to be a natural 2D crystal, no such information is available for PR til date. Neither its functional mechanism nor its 3D structure has been resolved so far. This PhD project is an attempt to gain a deeper insight so as to understand structural and functional characterization of PR. The approach combines the potentials of 2D crystallography, Atomic Force Microscopy and Solid State NMR techniques for characterization of this protein. Wide range of crystalline conditions was obtained as a result of 2D crystallization screens. This hints towards dominant protein protein interactions. Considering the high number of PR molecules reported per cell, it is likely that driven by such interactions, the protein has a native dense packing in the environment. The projection map represented low resolution of these crystals but suggested a donut shape oligomeric arrangement of protein in a hexagonal lattice with unit cell size of 87Å*87Å. Preliminary FTIR measurements indicated that the crystalline environment does not obstruct the photocycle of PR and K as well as M intermediate states could be identified. Single molecule force spectroscopy and atomic force microscopy on these 2D crystals was used to probe further information about the oligomeric state and nature of unfolding. The data revealed that protein predominantly exists as hexamers in crystalline as well as densely reconstituted regions but a small percentage of pentamers is also observed. The unfolding mechanism was similar to the other relatively well-characterized members of rhodopsin family. A good correlation of the atomic force microscopy and the electron microscopy data was achieved. Solid State NMR of the isotopically labeled 2D crystalline preparations using uniformly and selectively labeling schemes, allowed to obtain high quality SSNMR spectra with typical 15N line width in the range of 0.6-1.2 ppm. The measured 15N chemical shift value of the Schiff base in the 2D crystalline form was observed to be similar to the Schiff base chemical shift values for the functionally active reconstituted samples. This provides an indirect evidence for the active functionality of the protein and hence the folding. The first 15N assignment has been achieved for the Tryptophan with the help of Rotational Echo Double Resonance experiments. The 2D Cross Polarization Lee Goldberg measurements reflect the dynamic state of the protein inspite of restricted mobility in the crystalline state. The behavior of lipids as measured by 31P from the lipid head group showed that the lipids are not tightly bound to the protein but behave more like the lipid bilayer. The 13C-13C homonulear correlation experiments with optimized mixing time based on build up curve analysis, suggest that it is possible to observe individual resonances as seen in case of glutamic acid. The signal to noise was good enough to record a decent spectrum in a feasible period. The selective unlabeling is an efficient method for reduction in the spectral overlap. However, more efficient labeling schemes are required for further characterization. The present spectral resolution is good for individual amino acid investigation but for uniformly labeled samples, further improvement is required.
Tree-local MCTAG with shared nodes : an analysis of word order variation in German and Korean
(2004)
Tree Adjoining Grammars (TAG) are known not to be powerful enough to deal with scrambling in free word order languages. The TAG-variants proposed so far in order to account for scrambling are not entirely satisfying. Therefore, an alternative extension of TAG is introduced based on the notion of node sharing. Considering data from German and Korean, it is shown that this TAG-extension can adequately analyse scrambling data, also in combination with extraposition and topicalization.
In this paper, we present an open-source parsing environment (Tübingen Linguistic Parsing Architecture, TuLiPA) which uses Range Concatenation Grammar (RCG) as a pivot formalism, thus opening the way to the parsing of several mildly context-sensitive formalisms. This environment currently supports tree-based grammars (namely Tree-Adjoining Grammars (TAG) and Multi-Component Tree-Adjoining Grammars with Tree Tuples (TT-MCTAG)) and allows computation not only of syntactic structures, but also of the corresponding semantic representations. It is used for the development of a tree-based grammar for German.
This paper proposes a corpus encoding standard that meets the needs of linguistic research using a variety of linguistic data structures. The standard was developed in SFB 441, a research project at the University of Tuebingen. The principal concern of SFB 441 are the empirical data structures which feed into linguistic theory building. SFB 441 consists of several projects, most of which are building corpora to empirically investigate various linguistic phenomena in various languages (e.g. modal verbs in German, forms of address and politeness in Russian). These corpora will form the components of the "Tuebingen collection of reusable, empirical, linguistic data structures (TUSNELDA)". The TUSNELDA annotation standard aims at providing a uniform encoding scheme for all subcorpora and texts of TUSNELDA such that they can be processed with uniform standardized tools. To guarantee maximal reusability we use XML for encoding. Previous SGML standards for text encoding were provided by the Text Encoding Initiative (TEI) and the Expert Advisory Group on Language Engineering Standards (Corpus Encoding Standard, CES). The TUSNELDA standard is based on TEI and XCES (XML version of CES) but takes into account the specific needs of the SFB projects, i.e. the peculiarities of the examined languages and linguistic phenomena.