TY  - BOOK
ED  - Ishihara, Shinichiro
ED  - Jannedy, Stefanie
ED  - Schwarz, Anne
T1  - Interdisciplinary studies on information structure : ISIS ; Working papers of the SFB 632. - Vol. 8
N2  - The 8th volume of the working paper series Interdisciplinary Studies on Information Structure (ISIS) of the SFB 632 contains a collection of eight papers contributed by guest authors and SFB-members. The first paper on “Biased Questions” is an invited contribution by Nicholas Asher (CNRS, Laboratoire IRIT) & Brian Reese (University of Texas at Austin). Surveying English tag questions, negative polar questions, and what they term “focus” questions, they investigate the effects of prosody on discourse function and discourse structure and analyze the interaction between prosody and discourse in SDRT (Segmented Discourse Representation Theory). Stefan Hinterwimmer (A2) explores the interpretation of singular definites and universally quantified DPs in adverbially quantified English sentences. He suggests that the availability of a co-varying interpretation is more constrained in the case of universally quantified DPs than in the case of singular definites, because different from universally quantified DPs, co-varying definites are inherently focus-marked. The existence of striking similarities between topic/comment structure and bimanual coordination is pointed out and investigated by Manfred Krifka (A2). Showing how principles of bimanual coordination influence the expression of topic/comment structure beyond spoken language, he suggests that bimanual coordination might have been a preadaptation of the development of Information Structure in human communication. Among the different ways of expressing focus in Foodo, an underdescribed African Guang language of the Kwa family, the marked focus constructions are the central topic of the paper by Ines Fiedler (B1 & D2). Exploring the morphosyntactic facilities that Foodo has for focalization, she suggests that the two focus markers N and n have developed out of a homophone conjunction. Focus marking in another scarcely documented African tone language, the Gur language Konkomba, is treated by Anne Schwarz (B1 & D2). Comparing the two alleged focus markers lé and lá of the language, she argues that lé is better interpreted as a syntactic device rather than as a focus marker and shows that this analysis is corroborated by parallels in related languages. The reflexes of Information Structure in four different European languages (French, German, Greek and Hungarian) are compared and validated by Sam Hellmuth & Stavros Skopeteas (D2). The production data was collected with selected materials of the Questionnaire on Information Structure (QUIS) developed at the SFB. The results not only allow for an evaluation of the current elicitation paradigms, but also help to identify potentially fruitful venues of future research. Frank Kügler, Stavros Skopeteas (D2) & Elisabeth Verhoeven (University of Bremen) give an account of the encoding of Information Structure in Yucatec Maya, a Mayan tone language spoken on the Yucatecan peninsula in Mexico. The results of a production experiment lead them to the conclusion that focus is mainly expressed by syntax in this language. Stefanie Jannedy (D3) undertakes an instrumental investigation on the expressions and interpretation of focus in Vietnamese, a language of the Mon-Khmer family contrasting six lexical tones. The data strongly suggests that focus in Vietnamese is exclusively marked by prosody (intonational emphasis expressed via duration, f0 and amplitude) and that different focus conditions can reliably be recovered. This volume offers insights into current work conducted at the SFB 632, comprising empirical and theoretical aspects of Information Structure in a multitude of languages. Several of the papers mine field work data collected during the first phase of the SFB and explore the expression of Information Structure in tone and non-tone languages from various regions of the world.
T3  - Interdisciplinary studies on information structure : ISIS ; working papers of the SFB 632 - 8 
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14359
SN  - 978-3-939469-72-8
SN  - 1866-4725
SN  - 1614-4708
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ER  - 
TY  - INPR
A1  - Braun, Robert
A1  - Feudel, Fred
A1  - Seehafer, Norbert
T1  - Bifurcations and chaos in an array of forced vortices
N2  - We have studied the bifurcation structure of the incompressible two-dimensional Navier-Stokes equations with a special external forcing driving an array of 8×8 counterrotating vortices. The study has been motivated by recent experiments with thin layers of electrolytes showing, among other things, the formation of large-scale spatial patterns. As the strength of the forcing or the Reynolds number is raised the original stationary vortex array becomes unstable and a complex sequence of bifurcations is observed. The bifurcations lead to several periodic branches, torus and chaotic solutions, and other stationary solutions. Most remarkable is the appearance of solutions characterized by structures on spatial scales large compared to the scale of the forcing. We also characterize the different dynamic regimes by means of tracers injected into the fluid. Stretching rates and Hausdorff dimensions of convected line elements are calculated to quantify the mixing process. It turns out that for time-periodic velocity fields the mixing can be very effective.
T3  - NLD Preprints - 37 
Y1  - 1997
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14564
ER  - 
TY  - INPR
A1  - Witt, Annette
A1  - Neiman, Alexander
A1  - Kurths, Jürgen
T1  - Characterizing the dynamics of stochastic bistable systems by measures of complexity
N2  - The dynamics of noisy bistable systems is analyzed by means of Lyapunov exponents and measures of complexity. We consider both the classical Kramers problem with additive white noise and the case when the barrier fluctuates due to additional external colored noise. In case of additive noise we calculate the Lyapunov exponents and all measures of complexity analytically as functions of the noise intensity resp. the mean escape time. For the problem of fluctuating barrier the usual description of the dynamics with the mean escape time is not sufficient. The application of the concept of measures of complexity allows to describe the structures of motion in more detail. Most complexity measures sign the value of correlation time at which the phenomenon of resonant activation occurs with an extremum.
T3  - NLD Preprints - 36 
Y1  - 1997
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14556
ER  - 
TY  - INPR
A1  - Schmidtmann, Olaf
A1  - Feudel, Fred
A1  - Seehafer, Norbert
T1  - Nonlinear Galerkin methods for the 3D magnetohydrodynamic equations
N2  - The usage of nonlinear Galerkin methods for the numerical solution of partial differential equations is demonstrated by treating an example. We desribe the implementation of a nonlinear Galerkin method based on an approximate inertial manifold for the 3D magnetohydrodynamic equations and compare its efficiency with the linear Galerkin approximation. Special bifurcation points, time-averaged values of energy and enstrophy as well as Kaplan-Yorke dimensions are calculated for both schemes in order to estimate the number of modes necessary to correctly describe the behavior of the exact solutions.
T3  - NLD Preprints - 35 
Y1  - 1997
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14431
ER  - 
TY  - INPR
A1  - Jansen, Wolfgang
T1  - A note on the determination of the type of communication areas
N2  - The paper presents a method that determines, by standard numerical means, the type of mutual relations of fold and flip bifurcations (configured as a so-called communication area) of a map. Equation systems are developed for the computation of points where a transition between areas of different types occurs. Furthermore, it is shown that saddle area<->spring area transitions can exist which have not yet been considered in the literature. Analytical conditions of that transition are derived.
T3  - NLD Preprints - 33 
Y1  - 1996
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14339
ER  - 
TY  - INPR
A1  - Seehafer, Norbert
A1  - Zienicke, Egbert
A1  - Feudel, Fred
T1  - Absence of magnetohydrodynamic activity in the voltage-driven sheet pinch
N2  - We have numerically studied the bifurcation properties of a sheet pinch with impenetrable stress-free boundaries. An incompressible, electrically conducting fluid with spatially and temporally uniform kinematic viscosity and magnetic diffusivity is confined between planes at x1=0 and 1. Periodic boundary conditions are assumed in the x2 and x3 directions and the magnetofluid is driven by an electric field in the x3 direction, prescribed on the boundary planes. There is a stationary basic state with the fluid at rest and a uniform current J=(0,0,J3). Surprisingly, this basic state proves to be stable and apparently to be the only time-asymptotic state, no matter how strong the applied electric field and irrespective of the other control parameters of the system, namely, the magnetic Prandtl number, the spatial periods L2 and L3 in the x2 and x3 directions, and the mean values B¯2 and B¯3 of the magnetic-field components in these directions.
T3  - NLD Preprints - 32 
Y1  - 1996
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14328
ER  - 
TY  - INPR
A1  - Feudel, Fred
A1  - Seehafer, Norbert
A1  - Galanti, Barak
A1  - Rüdiger, Sten
T1  - Symmetry breaking bifurcations for the magnetohydrodynamic equations with helical forcing
N2  - We have studied the bifurcations in a three-dimensional incompressible magnetofluid with periodic boundary conditions and an external forcing of the Arnold-Beltrami-Childress (ABC) type. Bifurcation-analysis techniques have been applied to explore the qualitative behavior of solution branches. Due to the symmetry of the forcing, the equations are equivariant with respect to a group of transformations isomorphic to the octahedral group, and we have paid special attention to symmetry-breaking effects. As the Reynolds number is increased, the primary nonmagnetic steady state, the ABC flow, loses its stability to a periodic magnetic state, showing the appearance of a generic dynamo effect; the critical value of the Reynolds number for the instability of the ABC flow is decreased compared to the purely hydrodynamic case. The bifurcating magnetic branch in turn is subject to secondary, symmetry-breaking bifurcations. We have traced periodic and quasi- periodic branches until they end up in chaotic states. In particular detail we have analyzed the subgroup symmetries of the bifurcating periodic branches, which are closely related to the spatial structure of the magnetic field.
T3  - NLD Preprints - 31 
Y1  - 1996
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14317
ER  - 
TY  - JOUR
A1  - Lipke, Katrin
A1  - Zitzmann, Max
A1  - Amberger, Manuel
A1  - Ehlert, Carsten
A1  - Rößler, Dirk
A1  - Krüger, Frank
A1  - Ohrnberger, Matthias
T1  - Traveltime residuals at regional and teleseismic distances for SE-Asia
N2  - Traveltime residuals for worldwide seismic stations are calculated. We use P and S waves from earthquakes in SE-Asia at teleseismic and regional distances. The obtained station residuals help to enhance earthquake localisation. Furthermore we calculated regional source dependent station residuals. They show a systematic dependence of the locality of the source. These source dependent residuals reflect heterogenities along the path and can be used for a refinement of earthquake localisation.
N2  - Laufzeitresiduen für weltweite seismische Stationen werden berechnet. Wir nutzen P - und S-Wellen von Erdbeben in Südostasien in teleseismischen und regionalen Distanzen. Die so erhaltenen Stationsresiduen helfen, die Lokaliesierung von Erdbeben zu verbessern. Außerdem berechnen wir regional quellabhängige Stationsresiduen. Diese zeigen eine systematische Abhänbgigkeit vom Ort der Quelle. Sie spiegeln Heterogenitäten entlang des Strahlweges wieder und können für eine Verfeinerung der Ersbebenlokaliesierung genutzt werden.
KW  - Seismologie
KW  - Südostasien
KW  - Laufzeitresiduen
KW  - GITEWS
KW  - Wellengeschwindigkeiten
KW  - seismology
KW  - Southeast Asia
KW  - traveltime
KW  - residuals
KW  - GITEWS
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14117
ER  - 
TY  - INPR
A1  - Maaß, Peter
A1  - Rieder, Andreas
T1  - Wavelet-accelerated Tikhonov-Phillips regularization with applications
N2  - Contents: 1 Introduction 1.1 Tikhanov-Phillips Regularization of Ill-Posed Problems 1.2 A Compact Course to Wavelets 2 A Multilevel Iteration for Tikhonov-Phillips Regularization 2.1 Multilevel Splitting 2.2 The Multilevel Iteration 2.3 Multilevel Approach to Cone Beam Reconstuction 3 The use of approximating operators 3.1 Computing approximating families {Ah}
T3  - NLD Preprints - 30 
Y1  - 1996
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14104
ER  - 
TY  - INPR
A1  - Braun, Robert
A1  - Feudel, Fred
T1  - Supertransient chaos in the two-dimensional complex Ginzburg-Landau equation
N2  - We have shown that the two-dimensional complex Ginzburg-Landau equation exhibits supertransient chaos in a certain parameter range. Using numerical methods this behavior is found near the transition line separating frozen spiral solutions from turbulence. Supertransient chaos seems to be a common phenomenon in extended spatiotemporal systems. These supertransients are characterized by an average transient lifetime which depends exponentially on the size of the system and are due to an underlying nonattracting chaotic set.
T3  - NLD Preprints - 29 
Y1  - 1996
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14099
ER  - 
TY  - INPR
A1  - Voss, Henning
A1  - Kurths, Jürgen
A1  - Schwarz, Udo
T1  - Reconstruction of grand minima of solar activity from Delta 14 C data : linear and nonlinear signal analysis
N2  - Using a special technique of data analysis, we have found out 34 grand minima of solar activity obtained from a 7,700 years long Δ14C record. The method used rests on a proper filtering of the Δ14C record and the extrapolation of verifiable results for the later history back in time. Additionally, we use a method of nonlinear dynamics, the recurrence rate, to back up the results. Our findings are not contradictory to the record of solar maxima resp. minima by Eddy [5], but constitute a considerable extension. Hence, it has become possible to look closer at the validity of models. This way, we have tested several models for solar activity, esp. the model of Barnes et al. [1]. There are hints for that the grand minima might solely be driven by the 209 year period found in the Δ14C record.
T3  - NLD Preprints - 28 
Y1  - 1996
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-14083
ER  - 
TY  - INPR
A1  - Jansen, Wolfgang
T1  - CANDYS/QA : algorithms, programs, and user‘s manual
N2  - Contents: I. Algorithms 1. Theoretical Backround 2. Numerical Procedures 3. Graph Representation of the Solutions 4. Applications and Example II. Users' Manual 5. About the Program 6. The Course of a Qualitative Analysis 7. The Model Module 8. Input description 9. Output Description 10. Example 11. Graphics
T3  - NLD Preprints - 27 
Y1  - 1995
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13920
ER  - 
TY  - GEN
A1  - Zyla, Benjamin
T1  - Multilateralism à la Carte? : The Bush II administration and US foreign policy
N2  - The use of unilateral force under George W. Bush is not a new phenomenon in US foreign policy. As the author argues, it is merely a continuation of Bill Clinton’s foreign policy and is deeply rooted in both the foreign policy traditions of Jacksonianism and Wilsonianism. The analysis concludes that Clinton used unilateralist foreign policy with a 'smile' whereas the Bush administration uses it with an attitude.
N2  - Die unilaterale Außenpolitik unter George W. Bush ist kein neues Phänomen der US-Diplomatie. Dem Autor zufolge ist sie vielmehr eine Fortführung der Politik der Clinton-Regierung und hat ihre Wurzeln in den Traditionen eines Andrew Jackson und Woodrow Wilson. Clinton vermochte jedoch seine unilaterale Politik mit einem "Lächeln" zu verkaufen, wohingegen die Art und Weise der Bush-Administration stets Irritationen hervorrief.
KW  - US-Außenpolitik
KW  - George W. Bush
KW  - Unilateralismus
KW  - US foreign policy
KW  - George W. Bush
KW  - unilateralism
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13439
ER  - 
TY  - GEN
A1  - Köchy, Martin
T1  - Stochastic time series of daily precipitation for the interior of Israel
N2  - This contribution describes a generator of stochastic time series of daily precipitation for the interior of Israel from c. 90 to 900 mm mean annual precipitation (MAP) as a tool for studies of daily rain variability. The probability of rainfall on a given day of the year is described by a regular Gaussian peak curve function. The amount of rain is drawn randomly from an exponential distribution whose mean is the daily mean rain amount (averaged across years for each day of the year) described by a flattened Gaussian peak curve. Parameters for the curves have been calculated from monthly aggregated, long-term rain records from seven meteorological stations. Parameters for arbitrary points on the MAP gradient are calculated from a regression equation with MAP as the only independent variable. The simple structure of the generator allows it to produce time series with daily rain patterns that are projected under climate change scenarios and simultaneously control MAP. Increasing within-year variability of daily precipitation amounts also increases among-year variability of MAP as predicted by global circulation models. Thus, the time series incorporate important characteristics for climate change research and represent a flexible tool for simulations of daily vegetation or surface hydrology dynamics.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 029 
KW  - stochastische Zeitreihen
KW  - täglicher Niederschlag
KW  - Israel
KW  - Klimawandel
KW  - stochastic time series
KW  - daily precipitation
KW  - Israel
KW  - climate change
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13155
ER  - 
TY  - GEN
A1  - Kaafarani, Bilal R.
A1  - Wex, Brigitte
A1  - Strehmel, Bernd
A1  - Neckers, Douglas C.
T1  - Structural concept for fluorinated Y-enynes with solvatochromic properties
N2  - An approach to the development of fluorescent probes to follow polymerizations in situ using fluorinated cross-conjugated enediynes (Y-enynes) is reported. Different substitution patterns in the Y-enynes result in distinct solvatochromic behavior. β,β-Bis(phenylethynyl)pentafluorostyrene 7, which bears no donor substituents and only fluorine at the styrene moiety, shows no solvatochromism. Donor substituted β,β-bis(3,4,5-trimethoxyphenylethynyl) pentafluorostyrene 8 and β,β-bis(4-butyl-2,3,5,6-tetrafluorophenylethynyl)-3,4,5-trimethoxystyrene 9 exhibit solvatochromism upon change of solvent polarity. Y-enyne 8 showed the largest solvatochromic shift (94 nm bathochromic shift) upon changing solvent from cyclohexane to acetonitrile. A smaller solvatochromic response (44 nm bathochromic shift) was observed for 9. Lippert–Mataga treatment of 8 and 9 yields slopes of -10,800 and -6,400 cm -1, respectively. This corresponds to a change in dipole moment of 9.6 and 6.9 D, respectively. The solvatochromic behavior in 8 and 9 supports the formation of an intramolecular charge transfer (ICT) state. The low fluorescence quantum yields are caused by competitive double bond rotation. The fluorescence decay time of 9 decreases in methyltetrahydrofuran from 2.1 ns at 77 K to 0.11 ns at 200 K. Efficient single bond rotation in 9 was frozen at -50 °C in a configuration in which the trimethoxyphenyl ring is perpendicular to the fluorinated rings. 7–9 are photostable compounds. The X-ray structure of 7 shows it is not planar and that its conjugation is distorted. Y-enyne 7 stacks in the solid state showing coulombic, actetylene–arene, and fluorine–π interactions.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 027 
Y1  - 2002
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13168
ER  - 
TY  - GEN
A1  - Reich, Oliver
A1  - Löhmannsröben, Hans-Gerd
A1  - Schael, Frank
T1  - Optical sensing with photon density waves: investigation of model media
N2  - Investigations with frequency domain photon density waves allow elucidation of absorption and scattering properties of turbid media. The temporal and spatial propagation of intensity modulated light with frequencies up to more than 1 GHz can be described by the P1 approximation to the Boltzmann transport equation. In this study, we establish requirements for the appropriate choice of turbid model media and characterize mixtures of isosulfan blue as absorber and polystyrene beads as scatterer. For these model media, the independent determination of absorption and reduced scattering coefficients over large absorber and scatterer concentration ranges is demonstrated with a frequency domain photon density wave spectrometer employing intensity and phase measurements at various modulation frequencies.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 026 
Y1  - 2003
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13147
ER  - 
TY  - GEN
A1  - Rößler, Dirk
A1  - Krüger, Frank
A1  - Ohrnberger, Matthias
T1  - Rupture propagation of recent large TsE off-coast Sumatra and Java
N2  - The spatio-temporal evolution of the three recent tsunamogenic earthquakes (TsE) off-coast N-Sumatra (Mw9.3), 28/03/2005 (Mw8.5) off-coast Nias, on 17/07/2006 (Mw7.7) off-coast Java. Start time, duration, and propagation of the rupture are retrieved. All parameters can be obtained rapidly after recording of the first-arrival phases in near-real time processing. We exploit semblance analysis, backpropagation and broad-band seismograms within 30°-95° distance. Image enhancement is reached by stacking the semblance of arrays within different directions. For the three events, the rupture extends over about 1150, 150, and 200km, respectively. The events in 2004, 2005, and 2006 had source durations of at least 480s, 120s, and 180s, respectively. We observe unilateral rupture propagation for all events except for the rupture onset and the Nias event, where there is evidence for a bilateral start of the rupture. Whereas average rupture speed of the events in 2004 and 2005 is in the order of the S-wave speed (≈2.5-3km/s), unusually slow rupturing (≈1.5 km/s) is indicated for the July 2006 event. For the July 2006 event we find rupturing of a 200 x 100 km wide area in at least 2 phases with propagation from NW to SE. The event has some characteristics of a circular rupture followed by unilateral faulting with change in slip rate. Fault area and aftershock distribution coincide. Spatial and temporal resolution are frequency dependent. Studies of a Mw6.0 earthquake on 2006/09/21 and one synthetic source show a ≈1° limit in resolution. Retrieved source area, source duration as well as peak values for semblance and beam power generally increase with the size of the earthquake making possible an automatic detection and classification of large and small earthquakes.
KW  - Tsunami
KW  - Erdbeben
KW  - Indischer Ozean
KW  - Bruchausbreitung
KW  - Seismologie
KW  - Tsunami
KW  - Earthquake
KW  - Indonesia
KW  - Indian Ocean
KW  - Rupture Propagation
KW  - Seismology
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13039
ER  - 
TY  - BOOK
ED  - Ishihara, Shinichiro
ED  - Schmitz, Michaela
ED  - Schwarz, Anne
T1  - Interdisciplinary studies on information structure : ISIS ; Working papers of the SFB 632 - Vol. 5
N2  - In this paper we compare the behaviour of adverbs of frequency (de Swart 1993) like usually with the behaviour of adverbs of quantity like for the most part in sentences that contain plural definites. We show that sentences containing the former type of Q-adverb evidence that Quantificational Variability Effects (Berman 1991) come about as an indirect effect of quantification over situations: in order for quantificational variability readings to arise, these sentences have to obey two newly observed constraints that clearly set them apart from sentences containing corresponding quantificational DPs, and that can plausibly be explained under the assumption that quantification over (the atomic parts of) complex situations is involved. Concerning sentences with the latter type of Q-adverb, on the other hand, such evidence is lacking: with respect to the constraints just mentioned, they behave like sentences that contain corresponding quantificational DPs. We take this as evidence that Q-adverbs like for the most part do not quantify over the atomic parts of sum eventualities in the cases under discussion (as claimed by Nakanishi and Romero (2004)), but rather over the atomic parts of the respective sum individuals.
T3  - Interdisciplinary studies on information structure : ISIS ; working papers of the SFB 632 - 5 
KW  - Adverbial Quantification
KW  - Situations
KW  - Tense Semantics
KW  - Adverbs of Frequency
KW  - Adverbs of Quantity
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-13047
SN  - 1866-4725
PB  - Universitätsverlag Potsdam
CY  - Potsdam
ER  - 
TY  - THES
A1  - Ott, Christian David
T1  - Stellar iron core collapse in {3+1} general relativity and the gravitational wave signature of core-collapse supernovae
T1  - Stellarer Eisenkernkollaps in Allgemeiner Relativitätstheorie und die Gravitationswellensignatur von Kern-Kollaps-Supernovae
N2  - I perform and analyse the first ever calculations of rotating stellar iron core collapse in {3+1} general relativity that start out with presupernova models from stellar evolutionary calculations and include a microphysical finite-temperature nuclear equation of state, an approximate scheme for electron capture during collapse and neutrino pressure effects. Based on the results of these calculations, I obtain the to-date most realistic estimates for the gravitational wave signal from collapse, bounce and the early postbounce phase of core collapse supernovae. I supplement my {3+1} GR hydrodynamic simulations with 2D Newtonian neutrino radiation-hydrodynamic supernova calculations focussing on (1) the late postbounce gravitational wave emission owing to convective overturn, anisotropic neutrino emission and protoneutron star pulsations, and (2) on the gravitational wave signature of accretion-induced collapse of white dwarfs to neutron stars.
N2  - Ich präsentiere die ersten Computer-Simulationen des rotierenden Kollapses stellarer Eisenkerne, die in der {3+1}-Zerlegung der Allgemeinen Relativitätstheorie durchgeführt werden und Vorsupernova-Sternmodelle aus Sternentwicklungsrechnungen, eine heiße nukleare Zustandsgleichung und ein näherungsweises Verfahren zur Beschreibung des Elektroneneinfangs enthalten und Neutrinodruck-Effekte berücksichtigen. Basierend auf den Ergebnissen dieser Rechnungen erhalte ich die zur Zeit realistischsten Vorhersagen für das Gravitationswellensignal der Kollaps, Abprall, Abkling und frühen Nach-Abprallphase einer Kern-Kollaps-Supernova. Neben den {3+1} Simulationen diskutiere ich newtonsche axisymmetrische Kern-Kollaps-Supernova-Simulationen mit Schwerpunkten auf: (1) der Gravitationswellenabstrahlung in der späten Nach-Abprallphase durch Konvektionsströmungen, anisotropische Neutrinoemission und Proto-Neutronenstern Pulsationen und (2) der Gravitationswellensignatur des Kollapses weißer Zwergsterne zu Neutronensternen, der durch Akkretion eingeleitet wird.
KW  - Gravitationswellen
KW  - Kern-Kollaps-Supernovae
KW  - Allgemeine Relativitätstheorie
KW  - Gravitational Waves
KW  - Core-Collapse Supernovae
KW  - General Relativity
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12986
ER  - 
TY  - JOUR
A1  - Rößler, Dirk
A1  - Krüger, Frank
A1  - Rümpker, Georg
A1  - Psencik, Ivan
T1  - Tensile source components of swarm events in West Bohemia in 2000 by considering seismic anisotropy
N2  - Earthquake swarms occur frequently in West Bohemia, Central Europe. Their occurrence is correlated with and propably triggered by fluids that escape on the earth's surface near the epicentres. These fluids raise up periodically from a seemingbly deep-seated source in the upper mantle. Moment tensors for swarm events in 1997 indicate tensile faulting. However, they were determined under assumption of seismic isotropy although anisotropy can be observed. Anisotropy may obscure moment tensors and their interpretation. In 2000, more than 10,000 swarm earthquakes occurred near Novy Kostel, West Bohemia. Event triggering by fluid injection is likely. Activity lasted from 28/08 until 31/12/00 (9 phases) with maximum ML=3.2. High quality P-wave seismograms were used to retrieve the source mechanisms for 112 events between 28/08/00 and 30/10/00 using > 20 stations. We determine the source geometry using a new algorithm and different velocity models including anisotropy. From inversions of P waves we observe ML<3.2, strike-slip events on steep N-S oriented faults with additional normal or reverse components. Tensile components seem to be evident for more than 60% of the processed swarm events in West Bohemia during the phases 1-7. Being most significant at great depths and at phases 1-4 during the swarm they are time and location dependent. Although tensile components are reduced when anisotropy is assumed they persist and seem to be important. They can be explained by pore-pressure changes due to the injection of fluids that raise up. Our findings agree with other observations e.g. correlation of fluid transport and seismicity, variations in b-value, forcing rate, and in pore pressure diffusion. Tests of our results show their significance.
KW  - Seismologie
KW  - Erbeben
KW  - Momententensor
KW  - Anisotropie
KW  - Vogtland
KW  - Seismology
KW  - tensile earthquake
KW  - moment tensor
KW  - anisotropy
KW  - West Bohemia
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12975
ER  - 
TY  - JOUR
A1  - Rößler, Dirk
A1  - Krüger, Frank
A1  - Ohrnberger, Matthias
T1  - Rupture propagation of the TsE (Mw7.7) on 17 July 2006 off-coast Java
N2  - The Mw=7.7 tsunamogenic earthquake (TsE) on 17 July 2006, 08:19:28 shock the Indian Ocean at about 15 km depth off-coast Java, Indonesia. It caused a local tsunami with wave heights exceeding 2 m. The death toll reached several hundred. Thousands of people were displaced. By means of standard array methods, we have investigated the propagation and the extent of the rupture front of the causative earthquake. Waveform similarity is expressed by means of the semblance. We back-propagate the semblance for first-arrival phases recorded at broad-band stations within teleseismic distances (30°-95°). Image enhancement is realised by stacking the semblance of 8 arrays within different epicentral and azimuthal directions. From teleseismic observations we find rupturing of a 200 x 100 km wide area in at least 2 phases with propagation from NW to SE and source duration >125 s. The event has some characteristics of a circular rupture followed by unilateral faulting with change in slip rate. Unusually slow rupturing (≈1.5 km/s) is indicated. Fault area and aftershock distribution coincide. Spatial and temporal resolution are frequency dependent. Studies of a Mw6.0 earthquake on 2006/09/21 and one synthetic source show a ≈1° limit in resolution. Retrieved source area, source duration as well as peak values for semblance and beam power increase with the size of the earthquake making possible an automatic detection and classification of large and small earthquakes.
KW  - Seismologie
KW  - Erdbeben
KW  - Tsunami
KW  - Indischer Ozean
Y1  - 2007
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12964
ER  - 
TY  - THES
A1  - Lunemann, Carolin
T1  - Quantum cryptography : security analysis of multiuser quantum communication with embedded authentication
N2  - Three quantum cryptographic protocols of multiuser quantum networks with embedded authentication, allowing quantum key distribution or quantum direct communication, are discussed in this work. The security of the protocols against different types of attacks is analysed with a focus on various impersonation attacks and the man-in-the-middle attack. On the basis of the security analyses several improvements are suggested and implemented in order to adjust the investigated vulnerabilities. Furthermore, the impact of the eavesdropping test procedure on impersonation attacks is outlined. The framework of a general eavesdropping test is proposed to provide additional protection against security risks in impersonation attacks.
N2  - In der Diplomarbeit werden drei verschiedene quantenkryptographische Protokolle mit dem Schwerpunkt auf authentifizierten Quantennetzwerken analysiert. Die Sicherheit der Protokolle gegenüber verschiedenen Angriffen wird untersucht, wobei der Fokus auf kompletten Personifikationsattacken („impersonation attacks“) liegt. Auf Basis der Sicherheitsanalyse und den Netzwerkanforderungen werden entsprechende Verbesserungen vorgeschlagen. Um die Gefahr von Personifikationen realistisch abschätzen zu können, wird außerdem der Einfluss des Testablaufs analysiert. Um zusätzlichen Schutz gegen Personifikationsattacken zu gewährleisten, werden die Rahmenbedingungen für eine allgemeine Testspezifikation festgelegt.
KW  - Kryptographie
KW  - Quantenkryptographie
KW  - Authentifizierung
KW  - Netzwerk
KW  - cryptography
KW  - quantum cryptography
KW  - authentication
KW  - multiuser
KW  - network
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12756
ER  - 
TY  - GEN
A1  - Köchy, Martin
A1  - Tielbörger, Katja
T1  - Hydrothermal time model of germination : parameters for 36 Mediterranean annual species based on a simplified approach
N2  - Germination rates and germination fractions of seeds can be predicted well by the hydrothermal time (HTT) model. Its four parameters hydrothermal time, minimum soil temperature, minimum soil moisture, and variation of minimum soil moisture, however, must be determined by lengthy germination experiments at combinations of several levels of soil temperature and moisture. For some applications of the HTT model it is more important to have approximate estimates for many species rather than exact values for only a few species. We suggest that minimum temperature and variation of minimum moisture can be estimated from literature data and expert knowledge. This allows to derive hydrothermal time and minimum moisture from existing data from germination experiments with one level of temperature and moisture. We applied our approach to a germination experiment comparing germination fractions of wild annual species along an aridity gradient in Israel. Using this simplified approach we estimated hydrothermal time and minimum moisture of 36 species. Comparison with exact data for three species shows that our method is a simple but effective method for obtaining parameters for the HTT model. Hydrothermal time and minimum moisture supposedly indicate climate related germination strategies. We tested whether these two parameters varied with the climate at the site where the seeds had been collected. We found no consistent variation with climate across species, suggesting that variation is more strongly controlled by site-specific factors.
N2  - Keimungsgeschwindigkeit und Anteil gekeimter Samen lassen sich gut mit dem Hydrothermalzeit-Modell bestimmen. Dessen vier Parameter Hydrothermalzeit, Mindesttemperatur, Mindestbodenfeuchte und Streuung der Mindestbodenfeuchte müssen jedoch durch aufwendige Keimungsversuche bei Kombinationen von mehreren Temperatur- und Feuchtigkeitsstufen bestimmt werden. Für manche Anwendungen des Hydrothermalzeit-Modells sind aber ungefähre Werte für viele Arten wichtiger als genaue Werte für wenige Arten. Wenn die Mindesttemperatur und die Streuung der Mindestfeuchte aus Veröffentlichungen und Expertenwissen geschätzt würde, können die Hydrothermalzeit und Mindestbodenfeuchte aus vorhandenen Daten von Keimungsversuchen mit nur einer Temperatur- und Feuchtigkeitsstufe berechnet werden. Wir haben unseren Ansatz auf einen Keimungsversuch zum Vergleich der Keimungsquote wilder einjähriger Arten entlang eines Trockenheitsgradienten in Israel angewendet. Mit diesem Ansatz bestimmten wir die Hydrothermalzeit und Mindestfeuchtigkeit von 36 Arten. Der Vergleich mit genauen Werten für drei Arten zeigt, dass mit unserem Ansatz Hydrothermalzeit-Parameter einfach und effektiv bestimmt werden können. Hydrothermalzeit und Mindestfeuchtigkeit sollten auch bestimmte klimabedingte Keimungsstrategien anzeigen. Deshalb testeten wir, ob diese zwei Parameter mit dem Klima am Ursprungsort der Samen zusammenhängen. Wir fanden jedoch keinen für alle Arten übereinstimmenden Zusammenhang, so dass die Unterschiede vermutlich stärker durch standörtliche als durch klimatische Ursachen hervorgerufen werden.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 022 
KW  - Keimungsrate
KW  - Dormanz
KW  - Hydrothermalzeit-Modell
KW  - einjährige Pflanzen
KW  - Mittelmeerraum
KW  - germination rate
KW  - dormancy
KW  - hydrothermal time model
KW  - annual plant species
KW  - Mediterranean
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12406
ER  - 
TY  - GEN
A1  - Engelhard, Sonja
A1  - Kumke, Michael Uwe
A1  - Löhmannsröben, Hans-Gerd
T1  - OPQS – optical process and quality sensing : exemplary applications in the beerbrewing and polyurethane foaming processes
N2  - Optical methods play an important role in process analytical technologies (PAT). Four examples of optical process and quality sensing (OPQS) are presented, which are based on three important experimental techniques: near-infrared absorption, luminescence quenching, and a novel method, photon density wave (PDW) spectroscopy. These are used to evaluate four process and quality parameters related to beer brewing and polyurethane (PU) foaming processes: the ethanol content and the oxygen (O2) content in beer, the biomass in a bioreactor, and the cellular structures of PU foam produced in a pilot production plant.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 004 
KW  - process analytical technology
KW  - beer
KW  - biomass
KW  - foam analysis
KW  - NIR spectroscopy
KW  - fluorescence quenching
KW  - photon density wave spectroscopy
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12191
ER  - 
TY  - GEN
A1  - Schmälzlin, Elmar
A1  - Walz, Bernd
A1  - Klimant, Ingo
A1  - Schewe, Bettina
A1  - Löhmannsröben, Hans-Gerd
T1  - Monitoring hormone-induced oxygen consumption in the salivary glands of the blowfly, Calliphora vicina, by use of luminescent microbeads
N2  - The salivary glands of the blowfly were injected with luminescent oxygen-sensitive microbeads. The changes in oxygen content within individual gland tubules during hormone-induced secretory activity were quantified. The measurements are based on an upgraded phase-modulation technique, where the phase shift of the sensor phosphorescence is determined independently from concentration and background signals. We show that the combination of a lock-in amplifier with a fluorescence microscope results in a convenient setup to measure oxygen concentrations within living animal tissues at the cellular level.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 006 
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12206
ER  - 
TY  - GEN
A1  - Hildebrandt, Nico
A1  - Charbonnière, Loïc J.
A1  - Ziessel, Raymond F.
A1  - Löhmannsröben, Hans-Gerd
T1  - Quantum dots as resonance energy transfer acceptors for monitoring biological interactions
N2  - Quantum dots (QDs) are common as luminescing markers for imaging in biological applications because their optical properties seem to be inert against their surrounding solvent. This, together with broad and strong absorption bands and intense, sharp tuneable luminescence bands, makes them interesting candidates for methods utilizing Forster Resonance Energy Transfer (FRET), e. g. for sensitive homogeneous fluoroimmunoassays (FIA). In this work we demonstrate energy transfer from Eu3+-trisbipyridin (Eu-TBP) donors to CdSe-ZnS-QD acceptors in solutions with and without serum. The QDs are commercially available CdSe-ZnS core-shell particles emitting at 655 nm (QD655). The FRET system was achieved by the binding of the streptavidin conjugated donors with the biotin conjugated acceptors. After excitation of Eu-TBP and as result of the energy transfer, the luminescence of the QD655 acceptors also showed lengthened decay times like the donors. The energy transfer efficiency, as calculated from the decay times of the bound and the unbound components, amounted to 37%. The Forster-radius, estimated from the absorption and emission bands, was ca. 77Å. The effective binding ratio, which not only depends on the ratio of binding pairs but also on unspecific binding, was obtained from the donor emission dependent on the concentration. As serum promotes unspecific binding, the overall FRET efficiency of the assay was reduced. We conclude that QDs are good substitutes for acceptors in FRET if combined with slow decay donors like Europium. The investigation of the influence of the serum provides guidance towards improving binding properties of QD assays.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 012 
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12213
ER  - 
TY  - GEN
A1  - Schuler, Benjamin
A1  - Lipman, Everett A.
A1  - Steinbach, Peter J.
A1  - Kumke, Michael Uwe
A1  - Eaton, William A.
T1  - Polyproline and the "spectroscopic ruler" revisited with single-molecule fluorescence
N2  - To determine whether Förster resonance energy transfer (FRET) measurements can provide quantitative distance information in single-molecule fluorescence experiments on polypeptides, we measured FRET efficiency distributions for donor and acceptor dyes attached to the ends of freely diffusing polyproline molecules of various lengths. The observed mean FRET efficiencies agree with those determined from ensemble lifetime measurements but differ considerably from the values expected from Förster theory, with polyproline treated as a rigid rod. At donor–acceptor distances much less than the Förster radius R0, the observed efficiencies are lower than predicted, whereas at distances comparable to and greater than R0, they are much higher. Two possible contributions to the former are incomplete orientational averaging during the donor lifetime and, because of the large size of the dyes, breakdown of the point-dipole approximation assumed in Förster theory. End-to-end distance distributions and correlation times obtained from Langevin molecular dynamics simulations suggest that the differences for the longer polyproline peptides can be explained by chain bending, which considerably shortens the donor–acceptor distances.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 008 
KW  - Förster resonance energy transfer
KW  - molecular dynamics
KW  - polypeptide
KW  - FRET
Y1  - 2005
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12229
ER  - 
TY  - GEN
A1  - Schmälzlin, Elmar
A1  - Dongen, Joost T. van
A1  - Klimant, Ingo
A1  - Marmodée, Bettina
A1  - Steup, Martin
A1  - Fishahn, Joachim
A1  - Geigenberger, Peter
A1  - Löhmannsröben, Hans-Gerd
T1  - An optical multifrequency phase-modulation method using microbeads for measuring intracellular oxygen concentrations in plants
N2  - A technique has been developed to measure absolute intracellular oxygen concentrations in green plants. Oxygen-sensitive phosphorescent microbeads were injected into the cells and an optical multifrequency phase-modulation technique was used to discriminate the sensor signal from the strong autofluorescence of the plant tissue. The method was established using photosynthesis-competent cells of the giant algae Chara corallina L., and was validated by application to various cell types of other plant species.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 007 
Y1  - 2005
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12232
ER  - 
TY  - GEN
A1  - Lemke, Matthias
A1  - Fernández-Trujillo, Rebeca
A1  - Löhmannsröben, Hans-Gerd
T1  - In-situ LIF analysis of biological and petroleum-based hydraulic oils on soil
N2  - Absorption and fluorescence properties of 4 hydraulic oils (3 biological and 1 petroleum-based) were investigated. In-situ LIF (laser-induced fluorescence) analysis of the oils on a brown sandy loam soil was performed. With calibration, quantitative detection was achieved. Estimated limits of detection were below ca. 500 mg/kg for the petroleum-based oil and ca. 2000 mg/kg for one biological oil. A semi-quantitative classification scheme is proposed for monitoring of the biological oils. This approach was applied to investigate the migration of a biological oil in soil-containing compartments, namely a soil column and a soil bed.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 011 
KW  - in-situ
KW  - optical oil sensor
KW  - lubricants
KW  - hydraulic oils
KW  - soil
KW  - laser induced
Y1  - 2005
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12268
ER  - 
TY  - GEN
A1  - Billard, Isabelle
A1  - Ansoborlo, Eric
A1  - Apperson, Kathleen
A1  - Arpigny, Sylvie
A1  - Azenha, M. Emilia
A1  - Birch, David
A1  - Bros, Pascal
A1  - Burrows, Hugh D.
A1  - Choppin, Gregory
A1  - Kumke, Michael Uwe
T1  - Aqueous solutions of Uranium(VI) as studied by time-resolved emission spectroscopy : a Round-Robin Test
N2  - Results of an inter-laboratory round-robin study of the application of time-resolved emission spectroscopy (TRES) to the speciation of uranium(VI) in aqueous media are presented. The round-robin study involved 13 independent laboratories, using various instrumentation and data analysis methods. Samples were prepared based on appropriate speciation diagrams and, in general, were found to be chemically stable for at least six months. Four different types of aqueous uranyl solutions were studied: (1) acidic medium where UO22+aq is the single emitting species, (2) uranyl in the presence of fluoride ions, (3) uranyl in the presence of sulfate ions, and (4) uranyl in aqueous solutions at different pH, promoting the formation of hydrolyzed species. Results between the laboratories are compared in terms of the number of decay components, luminescence lifetimes, and spectral band positions. The successes and limitations of TRES in uranyl analysis and speciation in aqueous solutions are discussed.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 005 
KW  - uranium (VI)
KW  - intercomparison
KW  - speciation
Y1  - 2003
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12318
ER  - 
TY  - GEN
A1  - Kumke, Michael Uwe
A1  - Frimmel, Fritz Hartmann
T1  - Stationary and time-resolved fluorescence for humic substances characterization
N2  - Steady-state and time-resolved fluorescence methods were applied to investigate the fluorescence properties of humic substances of different origins. Using standard 2D emission and total luminescence spectra, fluorescence maxima, the width of the fluorescence band and a relative fluorescence quantum efficiency were determined. Different trends for fulvic acids and humic acids were observed indicating differences in the heterogeneity of the sample fractions. The complexity of the fluorescence decay of humic substances is discussed and compared to simple model compounds. The effect of oxidation of humic substances on their fluorescence properties is discussed as well.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 014 
Y1  - 2002
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12353
ER  - 
TY  - GEN
A1  - Köchy, Martin
T1  - Photodegradation of grass litter in semi-arid grasslands : a global perspective
N2  - In a recent contribution in Nature (vol. 442, pp. 555-558) Austin & Vivanco showed that sunlight is the dominant factor for decomposition of grass litter in a semi-arid grassland in Argentine. The quantification of this effect was portrayed as a novel finding. I put this result in the context of three other publications from as early as 1980 that quantified photodegradation. My synopsis shows that photodegradation is an important process in semi-arid grasslands in South America, North America and eastern Europe.
KW  - Laubstreu
KW  - semi-arides Grasland
KW  - abiotische Zersetzung
KW  - UV-Licht
KW  - Schatten
KW  - leaf litter
KW  - semi-arid grassland
KW  - abiotic decomposition
KW  - UV radiation
KW  - shade
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-12006
ER  - 
TY  - GEN
A1  - Dosche, Carsten
A1  - Löhmannsröben, Hans-Gerd
A1  - Bieser, A.
A1  - Dosa, P. I.
A1  - Han, S.
A1  - Iwamoto, M.
A1  - Schleifenbaum, A.
A1  - Vollhardt, K. Peter C.
T1  - Photophysical properties of [N]phenylenes
N2  - In the present study, photophysical properties of [N]phenylenes were studied by means of stationary and time-resolved absorption and fluorescence spectroscopy (in THF at room temperature). For biphenylene (1) and linear [3]phenylene (2a), internal conversion (IC) with quantum yields ΦIC > 0.99 is by far the dominant mechanism of S1 state deactivation. Angular [3]phenylene (3a), the zig-zag [4]- and [5]phenylenes (3b), (3c), and the triangular [4]phenylene (4) show fluorescence emission with fluorescence quantum yieds and lifetimes between ΦF = 0.07 for (3a) and 0.21 for (3c) and τF = 20 ns for (3a) and 81 ns for (4). Also, compounds (3) and (4) exhibit triplet formation upon photoexcitation with quantum yields as high as ΦISC = 0.45 for (3c). The strong differences in the fluorescence properties and in the triplet fromation efficiencies between (1) and (2a) on one hand and (3) and (4) on the other are related to the remarkable variation of the internal conversion (IC) rate constants kIC. A tentative classification of (1) and (2a) as “fast IC compounds”, with kIC > 109 s-1, and of (3) and (4) as “slow IC compounds”, with kIC ≈ 107 s-1, is suggested. This classification cannot simply be related to Hückel’s rule-type concepts of aromaticity, because the group of “fast IC compounds” consists of “antiaromatic” (1) and “aromatic” (2a), and the group of “slow IC compounds” consists of “antiaromatic” (3b), (4) and “aromatic” (3a), (3c). The IC in the [N]phenylenes is discussed within the framework of the so-called energy gap law established for non-radiative processes in benzenoid hydrocarbons.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 001 
Y1  - 2002
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-11936
ER  - 
TY  - GEN
A1  - Löhmannsröben, Hans-Gerd
A1  - Beitz, Toralf
A1  - Luadien, Robert
A1  - Schultze, Rainer
T1  - Laser-based ion mobility spectrometry for sensing  of aromatic compounds
N2  - The drift time spectra of polycyclic aromatic hydrocarbons (PAH), alkylbenzenes and alkylphenylethers were recorded with a laser-based ion mobility (IM) spectrometer. The ion mobilities of all compounds were determined in helium as drift gas. This allows the calculation of the diffusion cross sections (Omegacalc) on the basis of the exact hard sphere scattering model (EHSSM) and their comparison with the experimentally determined diffusion cross sections (Omegaexp). These Omegaexp/Omegacalc-correlations are presented for molecules with a rigid structure like PAH and prove the reliability of the theoretical model and experimental method. The increase of the selectivity of IM spectrometry is demonstrated using resonance enhanced multiphoton ionisation (REMPI) at atmospheric pressure, realized by tuneable lasers. The REMPI spectra of nine alkylbenzenes and alkylphenylethers are investigated. On the basis of these spectra, the complete qualitative distinction of eight compounds in a mixture is shown. These experiments are extended to alkylbenzene isomer mixtures.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 003 
KW  - Laser
KW  - REMPI
KW  - Ion mobility spectrometry
KW  - PAH
Y1  - 2004
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-11892
ER  - 
TY  - THES
A1  - Hohberger, Horst
T1  - Semiclassical asymptotics for the scattering amplitude in the presence of focal points at infinity
T1  - Semiklassische Asymptotik der Streuamplitude bei unendlich fernen Fokalpunkten
N2  - We consider scattering in $\R^n$, $n\ge 2$, described by the Schr\"odinger operator $P(h)=-h^2\Delta+V$, where $V$ is a short-range potential. With the aid of Maslov theory, we give a geometrical formula for the semiclassical asymptotics as $h\to 0$ of the scattering amplitude $f(\omega_-,\omega_+;\lambda,h)$ $\omega_+\neq\omega_-$) which remains valid in the presence of focal points at infinity (caustics). Crucial for this analysis are precise estimates on the asymptotics of the classical phase trajectories and the relationship between caustics in euclidean phase space and caustics at infinity.
N2  - Wir betrachten Streuung in $\R^n$, $n\ge 2$, beschrieben durch den Schr\"odinger operator $P(h)=-h^2\Delta+V$, wo $V$ ein kurzreichweitiges Potential ist. Mit Hilfe von Maslov Theorie erhalten wir eine geometrische Formel fuer die semiklassische Asymptotik ($h\to 0$) der Streuamplitude $f(\omega_-,\omega_+;\lambda,h)$ ($\omega_+\neq\omega_-$) welche auch bei Vorhandensein von Fokalpunkten bei Unendlich (Kaustiken) gueltig bleibt.
KW  - Mathematik
KW  - Physik
KW  - Streutheorie
KW  - Streuamplitude
KW  - Semiklassik
KW  - mathematics
KW  - physics
KW  - scattering theory
KW  - semiclassics
KW  - scattering amplitude
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-11574
ER  - 
TY  - GEN
A1  - Fuhr, Harald
T1  - Institutional change and new incentive structures for development : can decentralization and better local governance help?
N2  - This paper focuses on some of the factors explaining recent trends in decentralisation, and some areas where decentralisation has had a positive impact, including bringing citizens into public affairs, improving sub-national public administration, and stimulating local economic development. It concludes by exploring the dangers and the implications for governments of differing capabilities starting out on the decentralisation path. More specifically, the paper stresses the underlying incentive structures within states in reform. It suggests a country-specific discussion of both vertical and horizontal incentive structures in decentralisation, as well as clear-cut accountability within a public sector in change. While vertical incentive structures mean defined rules for intergovernmental relationships, horizontal incentive structures mean defined rules between local governments, their citizens and the local private sector. Both sets of incentives need to be reformed jointly to stimulate better results from decentralisation and for better performance of local government. Neglecting one of them, could harm development. Above all, politics and processes are key to understanding, and eventually, managing decentralisation effectively.
Y1  - 1999
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-11492
ER  - 
TY  - GEN
A1  - Archer, Clive
T1  - The EU, security and the Baltic region
N2  - The end of the cold war division of the Baltic Sea in 1989, and the three Baltic states’ return to independence in 1991 created new opportunities for the decision-makers of the area, as well as new possibilities for fashioning security in the region. This article will examine the security debate affecting the Baltic Sea region in the post-cold war period, and in particular, the relevance of the European Union to that debate. The following section will examine various concepts of security relevant to the Baltic region; the third section looks at the EU and the Baltic area; and the last part deals with the implications that EU membership by the Baltic Sea states may have for the security of the Baltic Sea zone.
Y1  - 1999
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-11453
ER  - 
TY  - GEN
A1  - Hoffmann, Arthur
A1  - Longhurst, Kerry
T1  - German strategic culture and the changing role of the Bundeswehr
N2  - The article mobilises the concept of strategic culture in order to identify the impact of history upon contemporary security policy. The article will first look at the "wholesale construction" of a strategic culture after the Second World War in West Germany before exploring its impact upon security policy since the end of the Cold War in two areas: the Bundeswehr's out-of-area role and conscription. The central argument presented here is that the strategic culture of the former Federal Republic now writ large on to the new united Germany sets the context within which security policies are designed. This strategic culture, as will be argued, acts as both a facilitating and a restraining variable on behaviour, making certain policy options possible and others impossible.
Y1  - 1999
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-11448
ER  - 
TY  - GEN
A1  - Hocking, Brian
T1  - Bridging boundaries: creating linkages : non-central governments and multilayered policy environments
N2  - Observers of international politics have been conscious of the growing international involvement of non-central governments (NCGs), particularly in federal systems. These have been supplemented by the internationalisation of subnational actors in quasi-federal and even unitary states. One of the difficulties is that analysis has often been locked into the dominant paradigm debate in International Relations concerning who and who are not significant actors. Having briefly explored the nature of this changing environment, marked by a growing emphasis on access rather than control as a policy objective and the emergence of what is termed a 'catalytic diplomacy', the discussion focuses on the need for linkage between the levels of government in the pursuit of international as well as domestic policy goals. The nature of linkage mechanisms are discussed.
Y1  - 1996
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-11126
ER  - 
TY  - CHAP
A1  - Kempson, Ruth
A1  - Cann, Ronnie
T1  - Dialogue pressures and syntactic change
N2  - On the basis of the Dynamic Syntax framework, this paper argues that the production pressures in dialogue determining alignment effects and given versus new informational effects also drive the shift from case-rich free word order systems without clitic pronouns into systems with clitic pronouns with rigid relative ordering. The paper introduces assumptions of Dynamic Syntax, in particular the building up of interpretation through structural underspecification and update, sketches the attendant account of production with close coordination of parsing and production strategies, and shows how what was at the Latin stage a purely pragmatic, production-driven decision about linear ordering becomes encoded in the clitics in theMedieval Spanish system which then through successive steps of routinization yield the modern systems with immediately pre-verbal fixed clitic templates.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10469
ER  - 
TY  - CHAP
A1  - Wolska, Magdalena
A1  - Kruijff-Korbayová, Ivana
T1  - Modeling anaphora in informal mathematical dialogue
N2  - We analyze anaphoric phenomena in the context of building an input understanding component for a conversational system for tutoring mathematics. In this paper, we report the results of data analysis of two sets of corpora of dialogs on mathematical theorem proving. We exemplify anaphoric phenomena, identify factors relevant to anaphora resolution in our domain and extensions to the input interpretation component to support it.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10455
ER  - 
TY  - CHAP
A1  - DeVault, David
A1  - Stone, Matthew
T1  - Scorekeeping in an uncertain language game
N2  - Received views of utterance context in pragmatic theory characterize the occurrent subjective states of interlocutors using notions like common knowledge or mutual belief. We argue that these views are not compatible with the uncertainty and robustness of context-dependence in human–human dialogue. We present an alternative characterization of utterance context as objective and normative. This view reconciles the need for uncertainty with received intuitions about coordination and meaning in context, and can directly inform computational approaches to dialogue.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10448
ER  - 
TY  - CHAP
A1  - Saget, Sylvie
A1  - Guyomard, Marc
T1  - Goal-oriented dialog as a collaborative subordinated activity involving collective acceptance
N2  - Modeling dialog as a collaborative activity consists notably in specifying the contain of the Conversational Common Ground and the kind of social mental state involved. In previous work (Saget, 2006), we claim that Collective Acceptance is the proper social attitude for modeling Conversational Common Ground in the particular case of goal-oriented dialog. We provide a formalization of Collective Acceptance, besides elements in order to integrate this attitude in a rational model of dialog are provided; and finally, a model of referential acts as being part of a collaborative activity is provided. The particular case of reference has been chosen in order to exemplify our claims.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10420
ER  - 
TY  - CHAP
A1  - Mills, Gregory J.
A1  - Healey, Patrick G. T.
T1  - Clarifying spatial descriptions : local and global effects on semantic co-ordination
N2  - A key problem for models of dialogue is to explain the mechanisms involved in generating and responding to clarification requests. We report a 'Maze task' experiment that investigates the effect of 'spoof' clarification requests on the development of semantic co-ordination. The results provide evidence of both local and global semantic co-ordination phenomena that are not captured by existing dialogue co-ordination models.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10414
ER  - 
TY  - CHAP
A1  - Macura, Zoran
A1  - Ginzburg, Jonathan
T1  - Acquiring words across generations : introspectively or interactively?
N2  - How does a shared lexicon arise in population of agents with differing lexicons, and how can this shared lexicon be maintained over multiple generations? In order to get some insight into these questions we present an ALife model in which the lexicon dynamics of populations that possess and lack metacommunicative interaction (MCI) capabilities are compared. We ran a series of experiments on multi-generational populations whose initial state involved agents possessing distinct lexicons. These experiments reveal some clear differences in the lexicon dynamics of populations that acquire words solely by introspection contrasted with populations that learn using MCI or using a mixed strategy of introspection and MCI. The lexicon diverges at a faster rate for an introspective population, eventually collapsing to one single form which is associated with all meanings. This contrasts sharply with MCI capable populations in which a lexicon is maintained, where every meaning is associated with a unique word. We also investigated the effect of increasing the meaning space and showed that it speeds up the lexicon divergence for all populations irrespective of their acquisition method.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10408
ER  - 
TY  - CHAP
A1  - Lücking, Andy
A1  - Rieser, Hannes
A1  - Staudacher, Marc
T1  - Multi-modal integration for gesture and speech
N2  - Demonstratives, in particular gestures that "only" accompany speech, are not a big issue in current theories of grammar. If we deal with gestures, fixing their function is one big problem, the other one is how to integrate the representations originating from different channels and, ultimately, how to determine their composite meanings. The growing interest in multi-modal settings, computer simulations, human-machine interfaces and VRapplications increases the need for theories ofmultimodal structures and events. In our workshopcontribution we focus on the integration of multimodal contents and investigate different approaches dealing with this problem such as Johnston et al. (1997) and Johnston (1998), Johnston and Bangalore (2000), Chierchia (1995), Asher (2005), and Rieser (2005).
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10393
ER  - 
TY  - CHAP
A1  - Diderichsen, Philip
T1  - Cross recurrence quantification analysis of indefinite anaphora in Swedish dialog :  an eye-tracking pilot experiment
N2  - A new method is used in an eye-tracking pilot experiment which shows that it is possible to detect differences in common ground associated with the use of minimally different types of indefinite anaphora. Following Richardson and Dale (2005), cross recurrence quantification analysis (CRQA) was used to show that the tandem eye movements of two Swedish-speaking interlocutors are slightly more coupled when they are using fully anaphoric indefinite expressions than when they are using less anaphoric indefinites. This shows the potential of CRQA to detect even subtle processing differences in ongoing discourse.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10388
ER  - 
TY  - CHAP
A1  - Bergmann, Kirsten
A1  - Kopp, Stefan
T1  - Verbal or visual? : How information is distributed across speech and gesture in spatial dialog
N2  - In spatial dialog like in direction giving humans make frequent use of speechaccompanying gestures. Some gestures convey largely the same information as speech while others complement speech. This paper reports a study on how speakers distribute meaning across speech and gesture, and depending on what factors. Utterance meaning and the wider dialog context were tested by statistically analyzing a corpus of direction-giving dialogs. Problems of speech production (as indicated by discourse markers and disfluencies), the communicative goals, and the information status were found to be influential, while feedback signals by the addressee do not have any influence.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10375
ER  - 
TY  - CHAP
A1  - Kranstedt, Alfred
A1  - Lücking, Andy
A1  - Pfeiffer, Thies
A1  - Rieser, Hannes
A1  - Staudacher, Marc
T1  - Measuring and reconstructing pointing in visual contexts
N2  - We describe an experiment to gather original data on geometrical aspects of pointing. In particular, we are focusing upon the concept of the pointing cone, a geometrical model of a pointing’s extension. In our setting we employed methodological and technical procedures of a new type to integrate data from annotations as well as from tracker recordings. We combined exact information on position and orientation with rater’s classifications. Our first results seem to challenge classical linguistic and philosophical theories of demonstration in that they advise to separate pointings from reference.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10362
ER  - 
TY  - CHAP
A1  - Lücking, Andy
A1  - Rieser, Hannes
A1  - Staudacher, Marc
T1  - SDRT and multi-modal situated communication
N2  - Classical SDRT (Asher and Lascarides, 2003) discussed essential features of dialogue like adjacency pairs or corrections and up-dating. Recent work in SDRT (Asher, 2002, 2005) aims at the description of natural dialogue. We use this work to model situated communication, i.e. dialogue, in which sub-sentential utterances and gestures (pointing and grasping) are used as conventional modes of communication. We show that in addition to cognitive modelling in SDRT, capturing mental states and speech-act related goals, special postulates are needed to extract meaning out of contexts. Gestural meaning anchors Discourse Referents in contextually given domains. Both sorts of meaning are fused with the meaning of fragments to get at fully developed dialogue moves. This task accomplished, the standard SDRT machinery, tagged SDRSs, rhetorical relations, the up-date mechanism, and the Maximize Discourse Coherence constraint generate coherent structures. In sum, meanings from different verbal and non-verbal sources are assembled using extended SDRT to form coherent wholes.
Y1  - 2006
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10348
ER  -