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The determination of the atmospheric aerosol size distribution is an inverse illposed problem. The shape and the material composition of the air-carried particles are two substantial model parameters. Present evaluation algorithms only used an approximation with spherical homogeneous particles. In this paper we propose a new numerically efficient recursive algorithm for inhomogeneous multilayered coated and absorbing particles. Numerical results of real existing particles show that the influence of the two parameters on the model is very important and therefore cannot be ignored.
We have numerically studied the bifurcations and transition to chaos in a two-dimensional fluid for varying values of the Reynolds number. These investigations have been motivated by experiments in fluids, where an array of vortices was driven by an electromotive force. In these experiments, successive changes leading to a complex motion of the vortices, due to increased forcing, have been explored [Tabeling, Perrin, and Fauve, J. Fluid Mech. 213, 511 (1990)]. We model this experiment by means of two-dimensional Navier-Stokes equations with a special external forcing, driving a linear chain of eight counter-rotating vortices, imposing stress-free boundary conditions in the vertical direction and periodic boundary conditions in the horizontal direction. 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. Several steady states and periodic branches and a period doubling cascade appear on the route to chaos. For increasing values of the Reynolds number, shear flow develops, for which the spatial scale is large compared to the scale of the forcing. Furthermore, we have investigated the influence of the aspect ratio of the container as well as the effect of no-slip boundary conditions at the top and bottom, on the bifurcation scenario.
This paper deals with the electrical conductivity problem in geophysics. It is formulated as an elliptic boundary value problem of second order for a large class of bounded and unbounded domains. A special boundary condition, the so called "Complete Electrode Model", is used. Poincaré inequalities are formulated and proved in the context of weighted Sobolev spaces, leading to existence and uniqueness statements for the boundary value problem. In addition, a parameter-to-solution operator arising from the inverse conductivity problem in medicine (EIT) and geophysics is investigated mathematically and is shown to be smooth and analytic.
The development of rural areas concerning food security, sustainability and social-economic stability is key issue to the globalized community. Regarding the current state of climatic change, especially semi-arid regions in uenced by monsoon or El Niño are prone to extreme weather events. Droughts, ooding, erosion, degradation of soils and water quality and deserti cation are some of the common impacts. State of the art in hydrologic environmental modeling is generally operating under a reductionist paradigm (Sivapalan 2005). Even an enormous quantity of process-oriented models exists, we fail in due reproduction of complexly interacting processes in their effective scale in the space-time-continuum, as they are described through deterministic small-scale process theories (e.g. Beven 2002). Yet large amounts of parameters - with partly doubtful physical expression - and input data are needed. In contradiction to that most soft information about patterns and organizing principles cannot be employed (Seibert and McDonnell 2002). For an analysis of possible strategies on the one hand towards integrated hydrologic modeling as decision support and on the other hand for sustainable land use development the 512 km2 large catchment of the Mod river in Jhabua, Madhya Pradesh, India has been chosen. It is characterized by a setting of common problems of peripheral rural semi-arid human-eco-systems with intensive agriculture, deforestation, droughts and general hardship for the people. Scarce data and missing gauges are adding to the requirements of data acquisition and process description. The study at hand presents a methodical framework to combine eld scale data analysis and remote sensing for the setup of a database focusing plausibility over strict data accuracy. The catena-based hydrologic model WASA (Güntner 2002) employes this database. It is expanded by a routine for crop development simulation after the de Wit approach (e.g. in Bouman et al. 1996). For its application as decision support system an agentbased land use algorithm is developed which decides on base of site speci cations and certain constraints (like maximum pro t or best local adaptation) about the cropping. The new model is employed to analyze (some) land use strategies. Not anticipated and a priori de ned scenarios will account for the realization of the model but the interactions within the system. This study points out possible approaches to enhance the situation in the catchment. It also approaches central questions of ways towards due integrated hydrological modeling on catchment scale for ungauged conditions and to overcome current paradigms.
Die moderne Kultur- und Sozialgeschichte lässt sich – auf den Ebenen des Transports, der Informationsübertragung und der interpersonellen Kommunikation – als ein sich permanent steigernder Beschleunigungsprozess beschreiben. Insbesondere neuartige Medientechnologien verkürzen die zeitlichen Intervalle der Kommunikation zunehmend. Es ist davon auszugehen, dass sich die dem Geschwindigkeitsimperativ unterliegenden neuen Kommunikationsbedingungen in sprachlichen Innovationen niederschlagen und diese wiederum Indikatoren für Sprachwandel sind. In der jüngsten linguistischen Forschung wird allerdings vielfach die These geäußert, der Sprachgebrauch in den neuen Medien indiziere fundamentale Veränderungen der Schriftlichkeit und führe zu einem sprachlichen Verfall besonderen Ausmaßes. Diese These soll am Beispiel schriftbasierter Alltagskommunikation – vom Telegramm über den Brief und der Internetkommunikation bis hin zur SMS-Kommunikation – in medien-, kultur- und texthistorischen Zusammenhängen überprüft werden. Es geht darum, die kulturhistorischen Modalitäten der Medien- und Beschleunigungsgenese aufzudecken und spezifische mediale und kontextuelle Bedingungen sprachlicher Veränderungen herauszustellen.
Global Circulation Models of climate predict not only a change of annual precipitation amounts but also a shift in the daily distribution. To improve the understanding of the importance of daily rain pattern for annual plant communities, which represent a large portion of semi-natural vegetation in the Middle East, I used a detailed, spatially explicit model. The model explicitly considers water storage in the soil and has been parameterized and validated with data collected in field experiments in Israel and data from the literature. I manipulated daily rainfall variability by increasing the mean daily rain intensity on rainy days (MDI, rain volume/day) and decreasing intervals between rainy days while keeping the mean annual amount constant. In factorial combination, I also increased mean annual precipitation (MAP). I considered five climatic regions characterized by 100, 300, 450, 600, and 800 mm MAP. Increasing MDI decreased establishment when MAP was >250 mm but increased establishment at more arid sites. The negative effect of increasing MDI was compensated by increasing mortality with increasing MDI in dry and typical Mediterranean regions (c. 360–720 mm MAP). These effects were strongly tied to water availability in upper and lower soil layers and modified by competition among seedlings and adults. Increasing MAP generally increased water availability, establishment, and density. The order of magnitudes of MDI and MAP effects overlapped partially so that their combined effect is important for projections of climate change effects on annual vegetation. The effect size of MAP and MDI followed a sigmoid curve along the MAP gradient indicating that the semi-arid region (≈300 mm MAP) is the most sensitive to precipitation change with regard to annual communitie
A water quality model for shallow river-lake systems and its application in river basin management
(2007)
This work documents the development and application of a new model for simulating mass transport and turnover in rivers and shallow lakes. The simulation tool called 'TRAM' is intended to complement mesoscale eco-hydrological catchment models in studies on river basin management. TRAM aims at describing the water quality of individual water bodies, using problem- and scale-adequate approaches for representing their hydrological and ecological characteristics. The need for such flexible water quality analysis and prediction tools is expected to further increase during the implementation of the European Water Framework Directive (WFD) as well as in the context of climate change research. The developed simulation tool consists of a transport and a reaction module with the latter being highly flexible with respect to the description of turnover processes in the aquatic environment. Therefore, simulation approaches of different complexity can easily be tested and model formulations can be chosen in consideration of the problem at hand, knowledge of process functioning, and data availability. Consequently, TRAM is suitable for both heavily simplified engineering applications as well as scientific ecosystem studies involving a large number of state variables, interactions, and boundary conditions. TRAM can easily be linked to catchment models off-line and it requires the use of external hydrodynamic simulation software. Parametrization of the model and visualization of simulation results are facilitated by the use of geographical information systems as well as specific pre- and post-processors. TRAM has been developed within the research project 'Management Options for the Havel River Basin' funded by the German Ministry of Education and Research. The project focused on the analysis of different options for reducing the nutrient load of surface waters. It was intended to support the implementation of the WFD in the lowland catchment of the Havel River located in North-East Germany. Within the above-mentioned study TRAM was applied with two goals in mind. In a first step, the model was used for identifying the magnitude as well as spatial and temporal patterns of nitrogen retention and sediment phosphorus release in a 100~km stretch of the highly eutrophic Lower Havel River. From the system analysis, strongly simplified conceptual approaches for modeling N-retention and P-remobilization in the studied river-lake system were obtained. In a second step, the impact of reduced external nutrient loading on the nitrogen and phosphorus concentrations of the Havel River was simulated (scenario analysis) taking into account internal retention/release. The boundary conditions for the scenario analysis such as runoff and nutrient emissions from river basins were computed by project partners using the catchment models SWIM and ArcEGMO-Urban. Based on the output of TRAM, the considered options of emission control could finally be evaluated using a site-specific assessment scale which is compatible with the requirements of the WFD. Uncertainties in the model predictions were also examined. According to simulation results, the target of the WFD -- with respect to total phosphorus concentrations in the Lower Havel River -- could be achieved in the medium-term, if the full potential for reducing point and non-point emissions was tapped. Furthermore, model results suggest that internal phosphorus loading will ease off noticeably until 2015 due to a declining pool of sedimentary mobile phosphate. Mass balance calculations revealed that the lakes of the Lower Havel River are an important nitrogen sink. This natural retention effect contributes significantly to the efforts aimed at reducing the river's nitrogen load. If a sustainable improvement of the river system's water quality is to be achieved, enhanced measures to further reduce the immissions of both phosphorus and nitrogen are required.
There is already strong evidence that temperate lakes have been highly vulnerable to human induced climate warming during the last century. Hitherto climate impact studies have mainly focussed on the impacts of the recent long-term warming in winter and spring and little is known on the influence of climate warming on temperate lakes in summer. In the present thesis, I studied some aspects, which may have been strongly involved in determining the response of a lake to climate warming in summer. Thereby I have focussed on climate induced impacts on the thermal characteristics and the phenology and abundance of summer plankton in a shallow polymictic lake (Müggelsee, Germany). First, the influence of climate warming on the phenology and abundance of the lake plankton was investigated across seasons. Fast-growing spring phytoplankton and zooplankton (Daphnia) advanced largely synchronously, whereas long-term changes in the phenology of slow-growing summer zooplankton were clearly species-specific and not synchronised. The phenology and/or abundance of several summer copepod species changed according to their individual thermal requirements at decisive developmental stages such as emergence from diapause in spring. The study emphasises that not only the degree of warming, but also its timing within the annual cycle is of great ecological importance. To analyse the impact of climate change on the thermal characteristics of the lake, I examined the long-term development of the daily epilimnetic temperature extrema during summer. The study demonstrated for the first time for lakes that the daily epilimnetic minima (during nighttime) have increased more rapidly than the daily epilimnetic maxima (during daytime), resulting in a distinct decrease in the daily epilimnetic temperature range. This day-night asymmetry in epilimnetic temperature was likely caused by an increased nighttime emission of long-wave radiation from the atmosphere. This underlines that not only increases in air temperature, but also changes in other meteorological variables such as wind speed, relative humidity and cloud cover may play an important role in determining the lake temperature with respect to further climate change. Furthermore, a short-term analysis on the mixing regime of the polymictic lake was conducted to examine the frequency and duration of stratification events and their impacts on dissolved oxygen, dissolved nutrients and summer phytoplankton. Even during the longest stratification events (heatwaves in 2003 and 2006) the thermal characteristics of the lake differed from those typically found in shallow dimictic lakes, which exhibit a continuous stratification during summer. Particularly, hypolimnetic temperatures were higher, favouring the depletion of oxygen and the accumulation of dissolved nutrient in the hypolimnion. Thermal stratification will be very likely amplified in the future, thus, I conclude that polymictic lakes will be very vulnerable to alterations in the thermal regime with respect to projections of further climate change during summer. Finally, a long-term case study on the long and short-term changes in the development of the planktonic larvae of the freshwater mussel Dreissena polymorpha was performed to analyse the impacts of simultaneous changes in the thermal and in the trophic regime of the lake. Both the climate warming and the decrease in external nutrient load were important in determining the abundance of the pelagic larvae by affecting different features of the life-history of this species throughout the warm season. The long-term increase in the abundance and length of larvae was related to the decrease in external nutrient loading and the change in phytoplankton composition. However, the recent heatwaves in 2003 and 2006 have offset this positive effect on larval abundance, due to unfavourable low oxygen concentrations that had resulted from extremely long stratification events, mimicking the effects of nutrient enrichment. Climate warming may thus induce counteracting effects in productive shallow lakes that underwent lake restoration through a decrease in external nutrient loading. I conclude that not only the nature of climate change and thus the timing of climate warming throughout the seasons and the occurrence of climatic extremes as heatwaves, but also site-specific lake conditions as the thermal mixing regime and the trophic state are crucial factors governing the impacts of climate warming on internal lake processes during summer. Consequently, further climate impact research on lake functioning should focus on how the different lake types respond to the complex environmental forcing in summer, to allow for a comprehensive understanding of human induced environmental changes in lakes.
The stability of the quiescent ground state of an incompressible, viscous and electrically conducting fluid sheet, bounded by stress-free parallel planes and driven by an external electric field tangential to the boundaries, is studied numerically. The electrical conductivity varies as cosh–2(x1/a), where x1 is the cross-sheet coordinate and a is the half width of a current layer centered about the midplane of the sheet. For a <~ 0.4L, where L is the distance between the boundary planes, the ground state is unstable to disturbances whose wavelengths parallel to the sheet lie between lower and upper bounds depending on the value of a and on the Hartmann number. Asymmetry of the configuration with respect to the midplane of the sheet, modelled by the addition of an externally imposed constant magnetic field to a symmetric equilibrium field, acts as a stabilizing factor.
The bifurcations in a three-dimensional incompressible, electrically conducting fluid with an external forcing of the Roberts type have been studied numerically. The corresponding flow can serve as a model for the convection in the outer core of the Earth and is realized in an ongoing laboratory experiment aimed at demonstrating a dynamo effect. The symmetry group of the problem has been determined and special attention has been paid to symmetry breaking by the bifurcations. The nonmagnetic, steady Roberts flow loses stability to a steady magnetic state, which in turn is subject to secondary bifurcations. The secondary solution branches have been traced until they end up in chaotic states.
Antike in Potsdam-Sanssouci
(2007)
Die in diesem Band zusammengestellten Beiträge sollen zu einer aktiven Auseinandersetzung mit der Antikerezeption auf dem Parkgelände von Potsdam-Sanssouci anregen. Ein Aufsatz zur Gartenkunst in der Antike und in Sanssouci leitet den Band ein. Den Hauptteil bilden zahlreiche Führungsblätter zur Mythologie, Architektur, Malerei u.a. Sie sind besonders als Grundlage für die Planung von Exkursionen mit Schülergruppen geeignet, richten sich aber auch ganz allgemein an Freunde der Antike. Weitere Informationstexte, antike Quellen, Lösungen zu den Führungsblättern sowie Karten und praktische Hinweise für einen Potsdam-Besuch runden den Band ab.
The solar tachocline is a thin transition layer between the solar radiative zone rotating uniformly and the solar convection zone, which has a mainly latitudinal differential rotation profile. This layer has a thickness of less than $0.05R_{\sun}$ and is subject to extreme radial as well as latitudinal shears. Helioseismological estimates put this layer at roughly $0.7R_{\sun}$. The tachocline mostly resides in the sub-adiabatic, non-turbulent radiative interior, except for a small overlap with the convection zone on the top. Many proposed dynamo mechanisms involve strong toroidal magnetic fields in this transition region. The exact mechanisms behind the formation of such a thin layer is still disputed. A very plausible mechanism is the one involving a weak, relic poloidal magnetic field trapped inside the radiative zone, which is responsible for expelling differential rotation outwards. This was first proposed by \citet{RK97}. The present work develops this idea with numerical simulations including additional effects like meridional circulation. It is shown that a relic field of 1~Gauss or smaller would be sufficient to explain the observed thickness of the tachocline. The stability of the solar tachocline is addressed as the next part of the problem. It is shown that the tachocline is stable up to a differential rotation of 52\% in the absence of magnetic fields. This is a new finding as compared to the earlier two dimensional models which estimated the solar differential rotation (about 28\%) to be marginally stable or even unstable. The changed stability limit is attributed to the changed stability criterion of the 3-dimensional model which also involves radial gradients of the angular velocity. In the presence of toroidal magnetic field belts, the lowest non-axisymmetric mode is shown to be the most unstable one for the radiative part of the tachocline. It is estimated that the tachocline would become unstable for toroidal fields exceeding about 100~Gauss. With both formation and stability questions satisfactorily addressed, this work presents the most comprehensive analysis of the physical processes in the solar tachocline to date.
Im Zuge des Transformations- und Globalisierungsprozesses in Rumänien kommt es in den letzten 15 Jahren zu einer Annäherung an westliche Lebensmuster und parallel dazu zu einer Binnendiversifizierung der Lebensverhältnisse. Allerdings wird das Land nicht flächendeckend von den internationalen ökonomischen Verflechtungen erfasst, sondern es lässt sich eine noch stärkere regionale Ausdifferenzierung als vor der Wende von 1989 beobachten. Traditionelle und moderne Gesellschaften leben nach wie vor nebeneinander. In vielen ländlichen Räumen Rumäniens, so besonders in der wirtschaftlich eher schwachen Dobrudscha, haben sich traditionelle Lebensweisen, Besitzstrukturen, Arbeitstechniken und Bewirtschaftungsformen bis in die heutige Zeit erhalten. Im September 2004 wurden im Rahmen eines Geländekurses unter Berücksichtigung der Raum- und Minderheitenforschung sechs ausgewählte ethnische Minderheiten der Kulturlandschaft Dobrudscha, die in der wissenschaftlichen Literatur meist nur am Rande untersucht wird, während des noch laufenden Transformationsprozesses genauer betrachtet. Dabei wurde mit Hilfe von Experten- und Betroffenen-Interviews die ethnische, ökonomische, politische und kulturelle Situation in der Region dargestellt und analysiert. Karten, Tabellen und 50 Farbfotografien ergänzen den Band.
Our Solar system contains a large amount of dust, containing valuable information about our close cosmic environment. If created in a planet's system, the particles stay predominantly in its vicinity and can form extended dust envelopes, tori or rings around them. A fascinating example of these complexes are Saturnian rings containing a wide range of particles sizes from house-size objects in the main rings up to micron-sized grains constituting the E ring. Other example are ring systems in general, containing a large fraction of dust or also the putative dust-tori surrounding the planet Mars. The dynamical life'' of such circumplanetary dust populations is the main subject of our study. In this thesis a general model of creation, dynamics and death'' of circumplanetary dust is developed. Endogenic and exogenic processes creating dust at atmosphereless bodies are presented. Then, we describe the main forces influencing the particle dynamics and study dynamical responses induced by stochastic fluctuations. In order to estimate the properties of steady-state population of considered dust complex, the grain mean lifetime as a result of a balance of dust creation, life'' and loss mechanisms is determined. The latter strongly depends on the surrounding environment, the particle properties and its dynamical history. The presented model can be readily applied to study any circumplanetary dust complex. As an example we study dynamics of two dust populations in the Solar system. First we explore the dynamics of particles, ejected from Martian moon Deimos by impacts of micrometeoroids, which should form a putative tori along the orbit of the moon. The long-term influence of indirect component of radiation pressure, the Poynting-Robertson drag gives rise in significant change of torus geometry. Furthermore, the action of radiation pressure on rotating non-spherical dust particles results in stochastic dispersion of initially confined ensemble of particles, which causes decrease of particle number densities and corresponding optical depth of the torus. Second, we investigate the dust dynamics in the vicinity of Saturnian moon Enceladus. During three flybys of the Cassini spacecraft with Enceladus, the on-board dust detector registered a micron-sized dust population around the moon. Surprisingly, the peak of the measured impact rate occurred 1 minute before the closest approach of the spacecraft to the moon. This asymmetry of the measured rate can be associated with locally enhanced dust production near Enceladus south pole. Other Cassini instruments also detected evidence of geophysical activity in the south polar region of the moon: high surface temperature and extended plumes of gas and dust leaving the surface. Comparison of our results with this in situ measurements reveals that the south polar ejecta may provide the dominant source of particles sustaining the Saturn's E ring.
Aus dem Inhalt dieser Ausgabe: Artikel und Miszellen: Karl E. Grözinger: Manfred Voigts zum Sechzigsten - 2.5.2006 Caspar Battegay: Wie nicht erinnern? - Die Frage nach der Jüdischkeit in Heinrich Heines autobiographischen Texten Edith Lutz: Heinrich Heine im "Verein für Cultur und Wissenschaft der Juden" Jakob Hessing: Wahrheit und Dichtung - Die Damaskusaffäre und Heines Der Rabbi von Bacharach Elvira Grözinger: Im Venusberg. Zu Gesundheit und Krankheit bei Heinrich Heine zwischen Eros und Thanatos Sabine Bierwirth: Meilenstein der Zeitgeschichtsschreibung: Heinrich Heines Berichte über die Judenverfolgung in Damaskus 1840 Hans Otto Horch: Die unheilbar große Brüderkrankheit - Zum programmatischen Zeitgedicht Das neue Israelitische Hospital zu Hamburg von H. Heine Hendrik Madsen: Vom Überleben der toten Schrift - Eine medientheoretisch orientierte Lektüre des Jeremiabuches Manfred Voigts: Moses Mendelssohn und Franz Kafka: Die Heilige Schrift Olivia Franz-Klauser: Samaritanerforschung im 19. Jahrhundert: Die Anfänge der historischen Kritik im Schatten religiöser Vorurteile, gezeigt an der Rezeption Moritz Heidenheims (1824-1898) Rezensionen: Mark R. Cohen: Unter Kreuz und Halbmond. Die Juden im Mittelalter (Daniel Jütte) Erika Timm: Historische jiddische Semantik. (Karl E. Grözinger) David B. Ruderman, Giuseppe Veltri (Hrsg.): Cultural Intermediaries. Jewish Intellectuals in Early Modern Italy (Daniel Jütte) Gian Maria Varanini, Reinhold C. Mueller (Hrsg.): Ebrei nella Terraferma veneta del Quattrocento (Daniel Jütte) Stefanie B. Siegmund: The Medici State and the Ghetto of Florence (Daniel Jütte) Johannes Mordstein: Selbstbewußte Untertänigkeit (Robert Jütte) Werner Heegewaldt, Oliver Sander (Hrsg.): Salomo Sachs (Elvira Grözinger) Philipp Theisohn: Die Urbarkeit der Zeichen. Zionismus und Literatur - eine andere Poetik der Moderne (Joachim Schlör) Jascha Nemtsov: Die Neue Jüdische Schule in der Musik (Susanne Hudak-Laziç) Ines Sonder: Gartenstädte in Eretz Israel. (Robert Jütte) Cilly Kugelmann (Hrsg.): Weihnukka. Geschichten von Weihnachten und Chanukka. (Daniel Jütte) Moshe Zimmermann, Yotam Hotam (Hrsg.): Zweimal Heimat. Die Jeckes zwischen Mitteleuropa und Nahost. (Anat Feinberg) Birgit Schlachter: Schreibweisen der Abwesenheit. (Elvira Grözinger) Jüdische Studien in aller Welt: Juden und Judentum im Iran - Einige zufällige und weniger zufällige Reiseeindrücke (Hans-Michael Haußig) Nachrichten Rückblicke
Two-dimensional bouyancy-driven convection in a horizontal fluid layer with stress-free boundary conditions at top and bottom and periodic boundary conditions in the horizontal direction is investigated by means of numerical simulation and bifurcation-analysis techniques. As the bouyancy forces increase, the primary stationary and symmetric convection rolls undergo successive Hopf bifurcations, bifurcations to traveling waves, and phase lockings. We pay attention to symmetry breaking and its connection with the generation of large-scale horizontal flows. Calculations of Lyapunov exponents indicate that at a Rayleigh number of 2.3×105 no temporal chaos is reached yet, but the system moves nonchaotically on a 4-torus in phase space.
We investigate the cognitive control in polyrhythmic hand movements as a model paradigm for bimanual coordination. Using a symbolic coding of the recorded time series, we demonstrate the existence of qualitative transitions induced by experimental manipulation of the tempo. A nonlinear model with delayed feedback control is proposed, which accounts for these dynamical transitions in terms of bifurcations resulting from variation of the external control parameter. Furthermore, it is shown that transitions can also be observed due to fluctuations in the timing control level. We conclude that the complexity of coordinated bimanual movements results from interactions between nonlinear control mechanisms with delayed feedback and stochastic timing components.
The stability of the quiescent ground state of an incompressible viscous fluid sheet bounded by two parallel planes, with an electrical conductivity varying across the sheet, and driven by an external electric field tangential to the boundaries is considered. It is demonstrated that irrespective of the conductivity profile, as magnetic and kinetic Reynolds numbers (based on the Alfvén velocity) are raised from small values, two-dimensional perturbations become unstable first.
Three-dimensional bouyancy-driven convection in a horizontal fluid layer with stress-free boundary conditions at the top and bottom and periodic boundary conditions in the horizontal directions is investigated by means of numerical simulation and bifurcation-analysis techniques. The aspect ratio is fixed to a value of 2√2 and the Prandtl number to a value of 6.8. Two-dimensional convection rolls are found to be stable up to a Rayleigh number of 17 950, where a Hopf bifurcation leads to traveling waves. These are stable up to a Rayleigh number of 30 000, where a secondary Hopf bifurcation generates modulated traveling waves. We pay particular attention to the symmetries of the solutions and symmetry breaking by the bifurcations.
The ill-posed problem of aerosol size distribution determination from a small number of backscatter and extinction measurements was solved successfully with a mollifier method which is advantageous since the ill-posed part is performed on exactly given quantities, the points r where n(r) is evaluated may be freely selected. A new twodimensional model for the troposphere is proposed.
Die durch Phosphatidylserin Decarboxylase (PSD) katalysierte Decarboxylierung von Phosphatidylserin (PS) zu Phosphatidylethanolamin (PE) ist für Mitochondrien in Hefe und Mäusen von essentieller Bedeutung. Im Rahmen der vorliegenden Dissertation wurde erstmals die Rolle dieses PE-Syntheseweges in Pflanzen untersucht. Die drei in Arabidopsis identifizierten PSD Gene atPSD1, atPSD2, atPSD3 codieren für Enzyme, die in Membranen der Mitochondrien (atPSD1), der Tonoplasten (atPSD2) und des Endoplasmatischen Retikulums (atPSD3) lokalisiert sind. Der Beitrag der einzelnen PSDs zur PE-Synthese wurde anhand von psd Null-Mutanten untersucht. Dabei stellte sich atPSD3 als das Enzym mit der höchsten Aktivität heraus. Alternativ zum PSD-Weg wird in Arabidopsis PE auch mittels Aminoalkohol-phosphotransferase synthetisiert. Der Verlust der gesamten PSD-Aktivität, wie es in der erzeugten psd Dreifachmutante der Fall ist, wirkt sich ausschließlich auf die Lipidzusammensetzung in der Mitochondrienmembran aus. Demzufolge wird extramitochondriales PE hauptsächlich über die Aminoalkoholphosphotransferase synthetisiert. Die veränderte Lipidzusammensetzung der Mitochondrienmembran hatte jedoch keinen Einfluss auf die Anzahl, Größe und Ultrastruktur der Mitochondrien sowie auf das ADP/ATP-Verhältnis und die Respiration. Neben der Bereitstellung von Reduktionsäquivalenten beeinflusst die Funktionalität der Mitochondrien auch die Bildung von Blüten- und Staubblättern. Diese Blütenorgane waren in der psd Dreifachmutante stark verändert, und der Blütenphänotyp ähnelte der APETALA3-Mutante. Dieses homöotische Gen ist für die Ausbildung von Blüten- und Staubblättern verantwortlich. Für die Erzeugung der Mutanten psd2-1 und psd3-1 wurde ein T-DNA Vektor verwendet, der den Promotor des APETALA3 Gens enthielt, welcher in den Mutanten psd2-1, psd3-1 sowie psd2-1psd3-1 und der psd1psd2-1psd3-1 Dreifachmutante eine vergleichbare Co-Suppression des APETALA3 Gens hervorruft. Der Blütenphänotyp trat jedoch nur in der psd Dreifachmutante auf, da nur in ihr die Kombination von geringen Funktionstörungen der Mitochondrien, hervorgerufen durch veränderte Lipidzusammensetzung, mit der Co-Suppression von APETALA3 auftritt.
Interdisciplinary studies on information structure : ISIS ; Working papers of the SFB 632. - Vol. 8
(2007)
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.
Development and application of novel genetic transformation technologies in maize (Zea mays L.)
(2007)
Plant genetic engineering approaches are of pivotal importance to both basic and applied research. However, rapid commercialization of genetically engineered crops, especially maize, raises several ecological and environmental concerns largely related to transgene flow via pollination. In most crops, the plastid genome is inherited uniparentally in a maternal manner. Consequently, a trait introduced into the plastid genome would not be transferred to the sexually compatible relatives of the crops via pollination. Thus, beside its several other advantages, plastid transformation provides transgene containment, and therefore, is an environmentally friendly approach for genetic engineering of crop plants. Reliable in vitro regeneration systems allowing repeated rounds of regeneration are of utmost importance to development of plastid transformation technologies in higher plants. While being the world’s major food crops, cereals are among the most difficult-to-handle plants in tissue culture which severely limits genetic engineering approaches. In maize, immature zygotic embryos provide the predominantly used material for establishing regeneration-competent cell or callus cultures for genetic transformation experiments. The procedures involved are demanding, laborious and time consuming and depend on greenhouse facilities. In one part of this work, a novel tissue culture and plant regeneration system was developed that uses maize leaf tissue and thus is independent of zygotic embryos and greenhouse facilities. Also, protocols were established for (i) the efficient induction of regeneration-competent callus from maize leaves in the dark, (ii) inducing highly regenerable callus in the light, and (iii) the use of leaf-derived callus for the generation of stably transformed maize plants. Furthermore, several selection methods were tested for developing a plastid transformation system in maize. However, stable plastid transformed maize plants could not be yet recovered. Possible explanations as well as suggestions for future attempts towards developing plastid transformation in maize are discussed. Nevertheless, these results represent a first essential step towards developing chloroplast transformation technology for maize, a method that requires multiple rounds of plant regeneration and selection to obtain genetically stable transgenic plants. In order to apply the newly developed transformation system towards metabolic engineering of carotenoid biosynthesis, the daffodil phytoene synthase (PSY) gene was integrated into the maize genome. The results illustrate that expression of a recombinant PSY significantly increases carotenoid levels in leaves. The beta-carotene (pro-vitamin A) amounts in leaves of transgenic plants were increased by ~21% in comparison to the wild-type. These results represent evidence for maize to have significant potential to accumulate higher amounts of carotenoids, especially beta-carotene, through transgenic expression of phytoene synthases. Finally, progresses were made towards developing transformation technologies in Peperomia (Piperaceae) by establishing an efficient leaf-based regeneration system. Also, factors determining plastid size and number in Peperomia, whose species display great interspecific variation in chloroplast size and number per cell, were investigated. The results suggest that organelle size and number are regulated in a tissue-specific manner rather than in dependency on the plastid type. Investigating plastid morphology in Peperomia species with giant chloroplasts, plasmatic connections between chloroplasts (stromules) were observed under the light microscope and in the absence of tissue fixation or GFP overexpression demonstrating the relevance of these structures in vivo. Furthermore, bacteria-like microorganisms were discovered within Peperomia cells, suggesting that this genus provides an interesting model not only for studying plastid biology but also for investigating plant-microbe interactions.
In nature one commonly finds interacting complex oscillators which by the coupling scheme form small and large networks, e.g. neural networks. Surprisingly, the oscillators can synchronize, still preserving the complex behavior. Synchronization is a fundamental phenomenon in coupled nonlinear oscillators. Synchronization can be enhanced at different levels, that is, the constraints on which the synchronization appears. Those can be in the trajectory amplitude, requiring the amplitudes of both oscillators to be equal, giving place to complete synchronization. Conversely, the constraint could also be in a function of the trajectory, e.g. the phase, giving place to phase synchronization (PS). In this case, one requires the phase difference between both oscillators to be finite for all times, while the trajectory amplitude may be uncorrelated. The study of PS has shown its relevance to important technological problems, e.g. communication, collective behavior in neural networks, pattern formation, Parkinson disease, epilepsy, as well as behavioral activities. It has been reported that it mediates processes of information transmission and collective behavior in neural and active networks and communication processes in the Human brain. In this work, we have pursed a general way to analyze the onset of PS in small and large networks. Firstly, we have analyzed many phase coordinates for compact attractors. We have shown that for a broad class of attractors the PS phenomenon is invariant under the phase definition. Our method enables to state about the existence of phase synchronization in coupled chaotic oscillators without having to measure the phase. This is done by observing the oscillators at special times, and analyzing whether this set of points is localized. We have show that this approach is fruitful to analyze the onset of phase synchronization in chaotic attractors whose phases are not well defined, as well as, in networks of non-identical spiking/bursting neurons connected by chemical synapses. Moreover, we have also related the synchronization and the information transmission through the conditional observations. In particular, we have found that inside a network clusters may appear. These can be used to transmit more than one information, which provides a multi-processing of information. Furthermore, These clusters provide a multichannel communication, that is, one can integrate a large number of neurons into a single communication system, and information can arrive simultaneously at different places of the network.
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.
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.
Biochemical and physiological studies of Arabidopsis thaliana Diacylglycerol Kinase 7 (AtDGK7)
(2006)
A family of diacylglycerol kinases (DGK) phosphorylates the substrate diacylglycerol (DAG) to generate phosphatidic acid (PA) . Both molecules, DAG and PA, are involved in signal transduction pathways. In the model plant Arabidopsis thaliana, seven candidate genes (named AtDGK1 to AtDGK7) code for putative DGK isoforms. Here I report the molecular cloning and characterization of AtDGK7. Biochemical, molecular and physiological experiments of AtDGK7 and their corresponding enzyme are analyzed. Information from Genevestigator says that AtDGK7 gene is expressed in seedlings and adult Arabidopsis plants, especially in flowers. The AtDGK7 gene encodes the smallest functional DGK predicted in higher plants; but also, has an alternative coding sequence containing an extended AtDGK7 open reading frame, confirmed by PCR and submitted to the GenBank database (under the accession number DQ350135). The new cDNA has an extension of 439 nucleotides coding for 118 additional amino acids The former AtDGK7 enzyme has a predicted molecular mass of ~41 kDa and its activity is affected by pH and detergents. The DGK inhibitor R59022 also affects AtDGK7 activity, although at higher concentrations (i.e. IC50 ~380 µM). The AtDGK7 enzyme also shows a Michaelis-Menten type saturation curve for 1,2-DOG. Calculated Km and Vmax were 36 µM 1,2-DOG and 0.18 pmol PA min-1 mg of protein-1, respectively, under the assay conditions. Former protein AtDGK7 are able to phosphorylate different DAG analogs that are typically found in plants. The new deduced AtDGK7 protein harbors the catalytic DGKc and accessory domains DGKa, instead the truncated one as the former AtDGK7 protein (Gomez-Merino et al., 2005).
To characterise the habitat preferences of ring ouzel (Turdus torquatus) and blackbird (T. merula) in Switzerland, we adopt species distribution modelling and predict the species’ spatial distribution. We model on two different scales to analyse in how far downscaling leads to a different set of predictors to describe the realised habitat best. While the models on macroscale (grid of one square kilometre) cover the entire country, we select a set of smaller plots for modelling on territory scale. Whereas ring ouzels occur in altitudes above 1’000 m a.s.l. only, blackbirds occur from the lowlands up to the timber line. The altitudinal range overlap of the two species is up to 400 m. Despite both species coexist on macroscale, a direct niche overlap on territory scale is rare. Small-scale differences in vegetation cover and structure seem to play a dominant role for habitat selection. On macroscale however, we observe a high dependency on climatic variables mainly representing the altitudinal range and the related forest structure preferred by the two species. Applying the models for climate change scenarios, we predict a decline of suitable habitat for the ring ouzel with a simultaneous median altitudinal shift of +440 m until 2070. In contrast, the blackbird is predicted to benefit from higher temperatures and expand its range to higher elevations.
Inhalt 1 Einleitung 2 Transplantation und Effektivität/Effizienz von Institutionen 2.1 Institutionen und institutioneller Wandel 2.2 Pfadabhängigkeit der institutionellen Entwicklung 2.3 Inkonsistenz der institutionellen Entwicklung 2.4 Determinanten der Effektivität von Institutionen 2.5 Effizienz transplantierter Institutionen 3 Wettbewerbspolitik in Russland 3.1 Die institutionelle Verankerung der Wettbewerbspolitik 3.2 Marktstruktur und Wettbewerbspolitik 3.3 Das Wettbewerbsgesetz von 2006 3.4 Verstöße gegen das Wettbewerbsgesetz 4 Welche Fehler hat Russland bei der Transplantation derWettbewerbspolitik gemacht? 5 Ist Ineffektivität von transplantierten Institutionen unvermeidlich? 6 Abschließende Bemerkungen
Do institutions matter?
(2006)
Contens 1 Introduction 2 Institutions and the Institutional Change 2.1 Institutions and Theoretical Concepts in Economics 2.2 Path Dependence 2.3 Inconsistence of Institutional Development 2.4 Determinants of Effectiveness 2.5 Efficiency of New Institutions 3 What is “Competition Policy”? 4 The Competition Policy in Russia as an Institution 4.1 Establishment of the Competition Policy as an Institution 4.2 Market Structure and Competition Policy 4.3 Measures of Competition Policy 4.3.1 Prohibition of Competition Restrictive Agreements or Concerted Actions 4.3.2 Abuse of Dominance 4.3.3 Merger Control 4.3.4 Restrictive Action to Competition of Administrative Bodies 4.4 Violations of the Competition Law 4.5 Problems of the Russian Competition Policy 5 Which Mistakes Russia has made with the Implementation of theCompetition Policy? 6 Is a Lacking Effectiveness of Transplanted Institutions Inevitable? 7 Concluding Remarks
Inhalt 1 Einleitung 2 Eine skizzenhafte Darstellung des deutschen Systemsder Hausmüllentsorgung 3 Zum Begriffsverständnis des Markt- und Wettbewerbsversagens 4 Transaktionales Marktversagen als Begründung für dasdeutsche System der Hausmüllentsorgung 4.1 Zur Theorie des transaktionalen Marktversagens 4.1.1 Definition und Formen des transaktionalen Marktversagens 4.1.2 Zu den zentralen Begriffen „Transaktion“ und „Transaktionskosten“ 4.2 Die Ermittelbarkeit der Transaktionskosten 4.3 Tendenzaussagen zur Höhe der Transaktionskosten mit Hilfe transaktionskostendeterminierenderFaktoren - Theorie und Anwendung 4.3.1 Spezifität 4.3.2 Messbarkeit 4.3.3 Unsicherheit 4.3.4 Transaktionshäufigkeit 4.3.5 Transaktionsatmosphäre 4.4 Marktpreis und Produktionskosten 4.5 Zum Nutzen der Abfallentsorgung für den privaten Haushalt 4.6 Das Verwaltungsmonopol als alternative, transaktionskostensenkende,nicht-marktliche Lösung 4.7 Transaktionales Marktversagen als Legitimationsgrundlage für einestaatliche Vorgabe des Koordinationsmechanismus 5 Fazit
Inhalt 1 Einleitung 2 Energiepolitische Zielsetzungen und Begründung für die Förderung EEin der EU 3 Ausgestaltung der Förderpolitik für EE in der EU 4 Überblick über die Fördersysteme für RS 5 Verteilung der Fördersysteme in der EU 6 Status quo vs. Harmonisierung - one size fits all? 7 RECS System 8 Welches Fördermodell für Europa? 9 Ausgestaltung eines europäischen Systems 10 Ausblick
Inhalt 1 Einleitung 2 Transplantation und Effektivität/Effizienz von Institutionen 2.1 Institutionen und institutioneller Wandel 2.2 Pfadabhängigkeit der institutionellen Entwicklung 2.3 Inkonsistenz der institutionellen Entwicklung 2.4 Determinanten der Effektivität 2.5 Effizienz transplantierter Institutionen 3 Wettbewerbspolitik als Institution in Russland 3.1 Die institutionelle Verankerung der Wettbewerbspolitik 3.2 Marktstruktur und Wettbewerbspolitik 3.3 Maßnahmen der Wettbewerbspolitik 3.3.1 Kartellverbot 3.3.2 Missbrauchsaufsicht über marktbeherrschende Stellungen 3.3.3 Zusammenschlusskontrolle 3.4 Verstöße gegen das Wettbewerbsgesetz 3.5 Probleme der Wettbewerbspolitik 4 Welche Fehler hat Russland bei der Transplantationder Wettbewerbspolitik gemacht? 5 Ist eine mangelnde Effektivität von transplantierten Institutionenunvermeidlich? 6 Abschließende Bemerkungen
Seit den Anfängen empirisch-neurowissenschaftlicher Forschung gilt Sprachkompetenz zuvorderst als eine Leistung der Hirnrinde (Kortex), jedoch wurden v. a. im Zuge sich verbessernder bildgebender Verfahren aphasische Syndrome auch nach Läsionen subkortikaler Hirnregionen, insbesondere der Basalganglien und des Thalamus nachgewiesen. Diese Strukturen liegen in der Tiefe des Gehirns und kommunizieren über weit gefächerte Faserverbindungen mit dem Kortex. In erster Linie werden den Basalganglien senso-motorische Kontrollfunktionen zugewiesen. Dementsprechend werden diverse Erkrankungen, die durch Störungen physiologischer Bewegungsabläufe gekennzeichnet sind (z. B. Morbus Parkinson, Chorea Huntington), auf Funktionsdefekte dieser Strukturen zurückgeführt. Der Thalamus wird häufig als Relaisstation des Informationsaustauschs zwischen anatomisch entfernten Arealen des Nervensystems aufgefasst. Basalganglien und Thalamus werden jedoch auch darüber hinausgehende Funktionen, z. B. zur Bereitstellung, Aufrechterhaltung und Auslenkung von Aufmerksamkeit bei der Bearbeitung kognitiver Aufgaben zugesprochen. In der vorliegenden Arbeit wurde mit elektrophysiologischen Methoden untersucht, ob auf der Ebene von Thalamus und Basalganglien kognitive Sprachleistungen, spezifisch der syntaktischen und semantischen Verarbeitung nachgewiesen werden können und inwieweit sich eventuell subkortikale von kortikaler Sprachverarbeitung unterscheidet. Die Untersuchung spezieller Sprachfunktionen der Basalganglien und des Thalamus ist im Rahmen der operativen Behandlung bewegungsgestörter Patienten mit der sog. Tiefenhirnstimulation (DBS = engl. Deep Brain Stimulation) möglich. Hierbei werden Patienten mit Morbus Parkinson Stimulationselektroden in den Nucleus subthalamicus (STN) implantiert. Bei Patienten mit generalisierten Dystonien erfolgt die Implantation in den Globus pallidus internus (GPI) und bei Patienten mit essentiellem Tremor in den Nucleus ventralis intermedius (VIM). STN und GPI sind Kernareale der Basalganglien, der VIM ist Teil des motorischen Systems. Nach der Implantation besteht die Möglichkeit, direkt von diesen Elektroden elektroenzephalographische (EEG)-Signale abzuleiten und diese mit simultan abgeleiteten Oberflächen-EEG zu vergleichen. In dieser Arbeit wurden DBS-Patienten aus allen genannten Gruppen in Bezug auf Sprachverständnisleistungen untersucht. Neben der Präsentation korrekter Sätze hörten die Patienten Sätze mit syntaktischen oder semantischen Fehlern. In verschiedenen Studien wurden an der Skalp-Oberfläche EKP-Komponenten (EKP = ereigniskorrelierte Potentiale) beschrieben, welche mit der Verarbeitung solcher Fehler in Verbindung gebracht werden. So verursachen syntaktische Phrasenstrukturverletzungen eine frühe links-anteriore Negativierung (ELAN). Dieser Komponente folgt eine späte Positivierung (P600), die mit Reanalyse und Reparaturmechanismen in Verbindung gebracht wird. Semantische Verletzungen evozieren eine breite Negativierung um 400ms (N400). In den thalamischen Ableitungen wurden zwei zusätzliche syntaktische fehlerbezogene Komponenten gefunden, die (i) ~ 80ms nach der Skalp-ELAN und (ii) ~ 70ms vor der Skalp-P600 auftraten. Bei semantischen Verletzungen wurde im Thalamus ein fehlerbezogenes Potential nachgewiesen, welches weitgehend parallel mit dem am Skalp gefundenen Muster verläuft. Aus den Ergebnissen der vorliegenden Studie folgt, dass der Thalamus spezifische Sprachfunktionen erfüllt. Komponenten, die Sprachverarbeitungsprozesse reflektieren, konnten in den Basalganglienstrukturen STN und GPI nicht identifiziert werden. Aufgrund der erhobenen Daten werden zwei getrennte Netzwerke für die Verarbeitung syntaktischer bzw. semantischer Fehler angenommen. In diesen Netzwerken scheint der Thalamus spezifische Aufgaben zu übernehmen. In einem ‚Syntaxnetzwerk’ kommunizieren frontale Hirnstrukturen unter Einbeziehung des Thalamus mit parietalen Hirnstrukturen. Dem Thalamus wurde eine Mediationsfunktion in der syntaktischen Reanalyse zugesprochen. In einem ‚Semantiknetzwerk’ waren keine eindeutig zuordenbaren Prozesse auf thalamischer Ebene nachweisbar. Es wurde eine unscharfe, jedoch aber spezifische Aktivierung des Thalamus über den gesamten Zeitraum der kortikalen semantischen Analyse gezeigt, welche als Integration verschiedener Analysemechanismen gewertet wurde.
Inhalt 1 Einleitung 2 Die Ziele des EnWG 2005 3 Die wichtigsten Neuregelungen des EnWG 2005 3.1 Neuregelungen zwecks Förderung des Wettbewerbs 3.1.1 Netzzugang 3.1.2 Netzentgelte 3.1.3 Unbundling 3.1.4 Stromkennzeichnung 3.2 Neuregelungen im Interesse der Versorgungssicherheit 4 Auswirkungen der Neuregelungen auf die Ziele des EnWG 2005 4.1 Preisgünstigkeit 4.2 Versorgungssicherheit 4.3 Umweltverträglichkeit 4.4 Energieeffizienz und Verbraucherfreundlichkeit 5 Fazit
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.
A casual look at regional unemployment rates reveals that there are vast differences, which cannot be explained by different institutional settings. Our paper attempts to trace these differences in the labor market performance back to the regions' specialization in products that are more or less advanced in their product cycle. The model we develop shows how individual profit and utility maximization endogenously yields higher employment levels in the beginning. In later phases, however, employment decreases in the presence of process innovation. Our model suggests that the only way to escape from this vicious circle is to specialize in products that are at the beginning of their "economic life". The model is based on an interaction of demand and supply side forces.
Anhand eines paradigmatischen Modellbeispiels werden die Konsequenzen der Koexistenz vieler Attraktoren auf die globale Dynamik schwach dissipativer Systeme studiert. Es wird gezeigt, dass diese Systeme eine sehr reichhaltige Dynamik besitzen und extrem sensitiv gegenüber Störungen in den Anfangsbedingungen sind. Diese Systeme zeichnen sich durch eine extrem hohe Flexibilität ihres Verhaltens aus.
Textbook wisdom says that competition yields lower prices and higher consumer surplus than monopoly. We show in two versions of a simple location-product differentiation model with and without endogenous choice of products that these two results have to be qualified. In both models, more than half of the reasonable parameter values lead to higher prices with duopoly than with monopoly. If the product characteristics are exogenous to the firms, consumers may even be be better off with monopoly in average.
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.
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.
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.
Ziel dieser Arbeit ist die phänomenologische Untersuchung der Feuchteempfindlichkeit der elektrischen Eigenschaften dünner Polymerschichten. Diese Untersuchungen stellen gleichzeitig Vorarbeiten zur Entwicklung von Prototypen von zwei polymeren Dünnschicht-Feuchtesensoren dar, die sich durch die spezielle Auswahl der feuchtesensitiven Materialien jeweils durch eine besondere Eigenschaft gegenüber kommerziellen Massenprodukten auszeichnen. Ziel der Entwicklungsarbeiten für den ersten Prototypen war die Konstruktion eines schnellen Feuchtesensors, der plötzliche und sprunghafte Feuchteänderungen in der umgebenden Atmosphäre möglichst rasch detektieren kann. Dafür wurden dünne Schichten von Poly-DADMAC auf Interdigitalstrukturen aufgebracht, die einen möglichst direkten Kontakt zwischen feuchtesensitiver Schicht und umgebender, feuchter Atmosphäre gewährleisten. Als Messgrößen dienten die Wechselstromgrößen Widerstand und Kapazität der Schichten. Die Feuchtekennlinien der Schichten zeigen gute Konstanz und hohe Reproduzierbarkeit. Der Widerstand der Schichten ändert sich durch den Einfluss von Feuchte je nach Schichtdicke um 3 bis 5 Größenordnungen und eignet sich als Messgröße für die Feuchtigkeit im gesamten Feuchtebereich. Die Hysterese der Filme konnte auf kleiner als 2,5% r.F. bestimmt werden, die Reproduzierbarkeit auf besser als 1% r.F. Die Ansprechzeit der Schichten lässt sich schichtdickenabhängig zu 1 bis 10 Sekunden bestimmen. Hierbei zeigen besonders die dünnen Schichten kurze Ansprechzeiten. Zielstellung für den zweiten Feuchtesensor war die Entwicklung eines Prototypen, dessen sensitive Schicht sich biostatisch und biozid verhält, so dass er in biotischen Umgebungen eingesetzt werden kann. Es wurden fünf Polysulfobetaine synthetisiert, deren Biozidität und Biostatik mit dem Kontakttest nach Rönnpagel, dem ISO846-Test und Abbautests bestimmt wurde. Zwei Polymere – Poly-DMMAAPS (BT2) und Poly-[MSA-Styren-Sulfobetain] (BT5) – erwiesen sich als ausreichend biozid und biostatisch. Schichten dieser Polymere wurden auf Interdigitalstrukturen aufgezogen, anschließend wurden die Kennlinien dieser Proben aufgenommen. Die Messwerte zeigen für beide Polymere gute Konstanz und eine hohe Reproduzierbarkeit. BT2-Proben sind zwischen 20% und 80% r.F. besonders empfindlich und zeigen über einen Monat keine Langzeitdrift. Vernetzte Proben zeigen bis 50°C keinen temperaturbedingten Abfall der Feuchteempfindlichkeit. Der Einsatz vernetzter BT5-Schichten als kapazitiver Feuchtesensor ist bis etwa 70°C möglich, die Schichten sind selbst nach Lagerung im Hochvakuum und mehrfacher Betauung stabil. Damit liegen zwei funktionsfähige Prototypen von Feuchtesensoren vor, für die die meisten Kennwerte denen von vergleichbaren kommerziellen Feuchtesensoren entsprechen. Gleichzeitig zeichnen sie sich aber durch eine sehr niedrige Ansprechzeit bzw. eine ausreichende Lebensdauer unter biotischen Bedingungen aus.
Box-Simulationen von rotierender Magnetokonvektion im flüssigen Erdkern Numerische Simulationen der 3D-MHD Gleichungen sind mit Hilfe des Codes NIRVANA durchgeführt worden. Die Gleichungen für kompressible rotierende Magnetokonvektion wurden für erdähnliche Bedingungen numerisch in einer kartesischen Box gelöst. Charakteristische Eigenschaften mittlerer Größen, wie der Turbulenz-Intensität oder der turbulente Wärmefluss, die durch die kombinierte Wirkung kleinskaliger Fluktuationen entstehen, wurden bestimmt. Die Korrelationslänge der Turbulenz hängt signifikant von der Stärke und der Orientierung des Magnetfeldes ab, und das anisotrope Verhalten der Turbulenz aufgrund von Coriolis- und Lorentzkraft ist für schnellere Rotation wesentlich stärker ausgeprägt. Die Ausbildung eines isotropen Verhaltens auf kleinen Skalen unter dem Einfluss von Rotation alleine wird bereits durch ein schwaches Magnetfeld verhindert. Dies resultiert in einer turbulenten Strömung, die durch die vertikale Komponente dominiert wird. In Gegenwart eines horizontalen Magnetfeldes nimmt der vertikale turbulente Wärmefluss leicht mit zunehmender Feldstärke zu, so dass die Kühlung eines rotierenden Systems verbessert wird. Der horizontale Wärmetransport ist stets westwärts und in Richtung der Pole orientiert. Letzteres kann unter Umständen die Quelle für eine großskalige meridionale Strömung darstellen, während erstes in globalen Simulationen mit nicht axialsymmetrischen Randbedingungen für den Wärmefluss von Bedeutung ist. Die mittlere elektromotorische Kraft, die die Erzeugung von magnetischem Fluss durch die Turbulenz beschreibt, wurde unmittelbar aus den Lösungen für Geschwindigkeit und Magnetfeld berechnet. Hieraus konnten die entsprechenden α-Koeffizienten hergeleitet werden. Aufgrund der sehr schwachen Dichtestratifizierung ändert der α-Effekt sein Vorzeichen nahezu exakt in der Mitte der Box. Der α-Effekt ist positiv in der oberen Hälfte und negativ in der unteren Hälfte einer auf der Nordhalbkugel rotierenden Box. Für ein starkes Magnetfeld ergibt sich zudem eine deutliche abwärts orientierte Advektion von magnetischem Fluss. Ein Mean-Field Modell des Geodynamos wurde konstruiert, das auf dem α-Effekt basiert, wie er aus den Box-Simulationen berechnet wurde. Für eine äußerst beschränkte Klasse von radialen α-Profilen weist das lineare α^2-Modell Oszillationen auf einer Zeitskala auf, die durch die turbulente Diffusionszeit bestimmt wird. Die wesentlichen Eigenschaften der periodischen Lösungen werden präsentiert, und der Einfluss der Größe des inneren Kerns auf die Charakteristiken des kritischen Bereichs, innerhalb dessen oszillierende Lösungen auftreten, wurden untersucht. Reversals werden als eine halbe Oszillation interpretiert. Sie sind ein recht seltenes Ereignis, da sie lediglich dann stattfinden können, wenn das α-Profil ausreichend lange in dem periodische Lösungen erlaubenden Bereich liegt. Aufgrund starker Fluktuationen auf der konvektiven Zeitskala ist die Wahrscheinlichkeit eines solchen Reversals relativ klein. In einem einfachen nicht-linearen Mean-Field Modell mit realistischen Eingabeparametern, die auf den Box-Simulationen beruhen, konnte die Plausibilität des Reversal-Modells anhand von Langzeitsimulationen belegt werden.
This paper analyses the structural change in Russia during the transition from the planned to a market economy. With regard to the famous three sector hypothesis, broad economic sectors were formed as required by this theory. The computation of their shares at GNP at market prices using Input-Output tables, and the adjustment of results from distortions, generated as side effects of tax avoidance practices, shows results that clearly reject claims that Russia would be on the road to a post-industrial service economy. Instead, at least until 2001, a tendency of "primarisation" could be observed, that presents Russia closer to less-developed countries.
Instability in competition
(2005)
In this paper we show that Puu (2002) does not provide a stable solution to the location game, according to his own definition of stability. If the usual two-stage game is considered, where in the first stage a location is chosen once and forever, and in the second stage prices are determined, the equilibrium proves stable for a sizeable interval of parameters, however. Even though this procedure is most common in analyzing Hotelling's location problem, it is not satisfying because it exhibits an inconsistent informational structure. The search for a better concept of stability is imperative.
Inhalt 1 Einleitung 2 Die Eisenbahnreform in Großbritaninien 2.1 Zum Bedarf einer Reorganisation von British Rail 2.2 Die Phase der Liberalisierung - Die Railtrack-Ära (1994 - 2001) 2.3 Die Problematik der Infrastrukturbetreiber 3 Das derzeitige britische Eisenbahnwesen 3.1 Die Hauptakteure und deren Beziehung zueinander 3.2 Die Marktstruktur des britischen Eisenbahnverkehrs 3.3 Das Marktverhalten der marktbeherrschenden Unternehmen 4 Die Performanceentwicklung des britischen Eisenbahnsystems seit dem Beginn der Bahnreform im Jahre 1994 4.1 Beschreibung der methodischen Herangehensweise 4.2 Die Entwicklung der Outout-IIndikatoren seit Beginn der Bahnreform 4.3 Die Entwicklung der Input-Indikatoren seit Beginn der Bahnreform 4.4 Ableitung eines Kosten-Nutzen-Trends seit Beginn der Bahnreform 5 Die aktuelle Reformpläne der britischen Regierung 6 Erfolgreiche Maßnahmen und Fehler der britischen Eisenbahnreform 7 Fazit
Inhalt 1 Ausgangslage 2 Regional- und industriepolitische Maßnahmen 2.1 Begriffliche Vorbemerkungen 2.2 Wichtige Maßnahmenbereiche 2.3 Brutto- und Nettotransfers 3 Auswirkungen 4 Regional- und industriepolitische Reformalternativen 4.1 Fortführung der Solidarpakts 4.2 Sonderwirtschaftszone Ost 4.3 Förderung der Infrastruktur 5 Fazit
Inhalt 1 Einleitung 2 Institutionen aus ökonomischer Sicht 3 Rolle der Institutionen in der ökonomischen Theorie 4 Institutioneller Wandel 5 Besonderer Fall der Institutionenökonomie: Transformationsländer 6 Formelle und informelle Institutuionen in den Transformationsländern: ein Fall der Inkomsistenz 7 Fazit
In Mikro- und Industrieökonomik ist scheinbar gewiss, dassWettbewerb zu niedrigeren Preisen führt und dass Konsumenten von Wettbewerb profitieren, während die etablierten Unternehmen einen Nachteil erleiden. Dieser Beitrag verwendet ein raumwirtschaftliches Standardmodell, um zu zeigen, dass dies nicht immer so sein muss. Der Grund ist, dass durch den Marktzutritt gerade die Konsumenten, deren Preiselastizität am größten ist, von dem Unternehmen bei der Preisbildung nicht berücksichtigt werden.
Do economists matter?
(2005)
Inhalt 1 Einleitung 2 Angebot an wettbewerbspolitischen Leitbildern 2.1 Ziele der Wissenschaftler 2.2 Bedeutung wettbewerbspolitischer Leitbilder 2.2.1 Ordoliberalismus 2.2.2 Workability-Konzepte 2.2.3 Kantzenbachs Leitbild der optimalen Wettbewerbsintensität 2.2.4 Hoppmanns Leitbild der Wettbewerbsfreiheit 2.2.5 Chicago School 3 Nachfrage nach wettbewerbspolitischen Leitbildern 3.1 Unterschiedliche Rollen der Politiker 3.2 Politiker und Ausrichtung der Wettbewerbspolitik 3.3 Wettbewerbspolitische Leitbilder und US-amerikanische Antitrustpolitik 4 Einfluss wettbewerbspolitischer Leitbilder auf die europäische Fusionskontroller 4.1 Deutsche Grundlagen 4.2 Materiell-rechtliche-Regelungen der FKVO 4.3 Einflüsse der wettbewerbspolitischen Leitbilder 4.4 Positionen der Interessengruppen 5 Fazit
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.
Inhalt: 1 Einleitung 2 Überblick über den Stand der Forschung 3 Theoretische Grundlagen 3.1 Transmissionsmechanismus Vermögen, Vermögenspreise und Konsum 3.2 Vermögenseffekte im Konsum 4 Modellierung der Vermögenseffekte im Konsum 4.1 Intertemporale Budgetbeschränkung 4.2 Permanente Einkommenshypothese (PIH) 4.3 Lebenszyklushypothese (LCH) 4.4 Lebenszyklushypothese als multikointegrierte Konsumfunktion 4.5 Trägheitsannahme des Konsumwachstums 5 Ökonometrische Methodologie 5.1 EG2 von Engle und Granger 5.2 Dynamisches OLS nach Stock und Watson 5.3 Vektorfehlerkorrekturmodell (VECM) und Johansen-Verfahren 6 Statistische Datenbasis 7 Empirische Ergebnisse 7.1 Empirische Ergebnisse ausgewählter Studien 7.2 Empirische Ergebnisse für Deutschland 7.2.1 Test auf Integration 7.2.2 Ergebnisse EG2 7.2.3 Ergebnisse DOLS 7.2.4 Test auf Parameterstabilität 7.2.5 Ergebnisse VECM 7.2.6 Ergebnisse Impuls-Antwort-Analyse 7.3 Zusammenfassung der empirischen Ergebnisse 8 Geldpolitische Implikationen 9 Zusammenfassung
Inhalt: 1. Der Forschungsgegenstand der Statistischen Modellierung und Prognose 2. Informationsversorgung der Statistischen Modellierung und Prognose 3. Grundprinzipien der Statistischen Modellierung und Prognose 4. Grundstufen der Statistischen Modellierung und Prognose 5. Die statistische Trägheit in der Modellierung und Prognose 6. Theoretische Aspekte des Identifikationsproblems bei der Statistischen Modellierung und Prognose Schlussfolgerung
This volume presents annotation guidelines that have been developed in the context of the SFB 632, a collaborative research center entitled "Information Structure: the Linguistic Means for Structuring Utterances, Sentences and Texts". An important result of the SFB 632 are the SFB corpora from more than 20 typologically different languages, which have been annotated according to the guidelines presented here. The ultimate target of the data and its annotations is to support the study of Information Structure. Information Structure involves all levels of grammar and, hence, the present guidelines cover relevant aspects of all these levels: - Phonology - Morphology - Syntax - Semantics - Information Structure These levels are dealt with in individual chapters, containing tagset declarations with obligatory and optional tags, detailed annotation instructions, and illustrative examples. The volume also presents an evaluation of inter-annotator agreement of Syntax and Information Structural annotation.
Table of contens 1 Introduction 2 The concept of sustainability 2.1 Ecological sustainability 2.2 Social sustainability 2.3 Economic sustainability 2.4 The sustainability strategy of the german government 3 Effects of energy use on the enviromment 4 Requirements of the SSGG for energy policy 4.1 Ecological implications of thr SSGG 4.2 Social and economic requirements of the SSGG 5 The German Renewable Energies Act 5.1 Objectives 5.2 Design and mechanisms 5.3 Fees-in tariffs 6 Does the EEG meet the sustainability requirements of the SSGG? 6.1 Management rules 6.2 Social sustainability 6.3 Economic sustainability 6.4 Development tendencis 7 Possible amendments for more sustainability 7.1 Changing the promotional system 7.2 A European regulation
Bei dieser Publikation handelt es sich um ein Kompendium, gedacht als Selbststudienliteratur für linguistische Grundkurse und Einführungsveranstaltungen zur deutschen Sprache der Gegenwart. Im Mittelpunkt der Darstellung stehen jene Sprachformen des Deutschen, die sich in verschiedenen Kommunikationsbereichen (privater Alltag, Kunst, Wissenschaft, Bürokratie, Journalismus, Werbung) herausgebildet haben. In jedem dieser Bereiche hat die Sprache eine spezifische Funktion, d. h. einen anderen gesellschaftlichen Zweck. Funktionale Varietäten sind dementsprechend zweckbestimmte, kommunikationsbereichsbezogene Teilsprachen einer Einzelsprache. Traditionell werden sie auch Funktionalstile genannt. Das Kompendium umfasst zwei Hauptteile. An die Vermittlung theoretischer Grundlagen schließen sich Beschreibungsprotokolle an, die zu jeder funktionalen Varietät (Alltags-, Dichter-, Wissenschafts-, Behörden-, Presse- und Werbesprache) Auskunft geben über • die kommunikative Hauptleistung der Varietät, • die kommunikativen Rahmenbedingungen ihrer Verwendung, • ihre Bindung an kommunikative Gattungen (Text- und Gesprächssorten) und • ihr sprachliches Erscheinungsbild. Eingegangen wird auch auf Abgrenzungsfragen, so z. B. auf das Verhältnis von Alltagssprache und Umgangssprache, von Dichtersprache und Literatursprache, von Pressesprache und Mediensprache. Die Protokolle verzeichnen darüber hinaus Zusatzliteratur, die für ein vertiefendes Studium zu empfehlen ist
Social segregation in cities takes place where different household groups exist and when, according to Schelling, their location choice either minimizes the number of differing households in their neighborhood or maximizes their own group. In this contribution an evolutionary simulation based on a monocentric city model with externalities among households is used to discuss the spatial segregation patterns of four groups. The resulting complex spatial patterns can be shown as graphic animations. They can be applied as initial situation for the analysis of the effects a rent control has on segregation.
Optimal spatial patterns of two, three and four segregated household groups in a monocentric city
(2004)
Usually, in monocentric city models the spatial patterns of segregated household groups are assumed to be ring-shaped, while early in the 1930ies Hoyt showed that wedge-shaped areas empirically predominate. This contribution presents a monocentric city model with different household groups generating positive externalities within the groups. At first, border length is founded as a criterion of optimality. Secondly, it is shown that mixed patterns of concentric and wedge-shaped areas represent multiple equilibria if more than two groups of households are being considered. The welfare optimal segregated pattern depends on the relative purchasing power of different household groups.
Usually, in monocentric city models, the spatial patterns of segregated ethnic groups are assumed to be ring-shaped, whereas in the 1930ies Hoyt showed that empirically wedge-shaped areas predominate. In contrast to Rose-Ackerman.s discussion of the in.uence within a ring-shaped pattern which the aversion which different households in the context of racism have, Yinger showed that, depending on the population mix, a wedge-shaped pattern may arise if it is border length which causes the spatial pattern. In this contribution, a simulation based on a monocentric city model with two or more different household groups is used to derive spatial patterns. Wedge-shaped segregation is shown to be the result of positive externalities among similar households. Differences between households only lead to ring-shaped patterns if the e¤ect of a city center on spatial structure dominates neighborhood e¤ects. If more than two groups of households are being considered, mixed patterns of concentric and wedge-shaped areas arise.
Dem Schriftsteller Jorge Semprún wurde am 25. Mai 2007 die Ehrendoktorwürde der Philosophischen Fakultät der Universität Potsdam verliehen. Damit ehrt die Philosophische Fakultät seine Lebensleistung als Schriftsteller, Denker und engagierter Intellektueller unserer Zeit. Der Geehrte sprach zum Thema "Philosophie als Überlebenswissenschaft". Jorge Semprún, 1923 in Madrid/Spanien geboren, muss mit 14 Jahren zu Beginn des spanischen Bürgerkrieges mit seiner Familie nach Paris fliehen. Dort studiert er Philosophie an der Sorbonne. Im Jahre 1941 tritt er der kommunistischen Résistance-Bewegung "Francs- Tireurs et Partisans" bei. Zwei Jahre später wird er von der deutschen Gestapo verhaftet und in das Konzentrationslager Buchenwald deportiert. 1945 kehrt er nach Paris zurück. Zwischen 1957 und 1962 arbeitet er im Untergrund der Kommunistischen Partei im faschistischen Spanien. Seit 1964, dem Jahr, in dem er wegen der Abweichung von der Parteilinie aus der Kommunistischen Partei ausgeschlossen wurde, ist er schriftstellerisch tätig. Von 1988 bis 1991 war er Kultusminister Spaniens. Zu den bekanntesten Werken des Schriftstellers gehören "Die große Reise", "Der zweite Tod des Ramón Mercader", "Was für ein schöner Sonntag" sowie "Der weiße Berg".
Inhalt 1 Politikzyklus als konzeptioneller Bezugsrahmen 2 Ökonomische Problematik von Netzindustrien und Liberalisierungsgründe 3 Privatisierung und Marktöffnung als wirtschaftspolitische Aufgaben 4 Politisierung von Liberalisierungsinteressen 4.1 Politiker als Intermediäre 4.2 Zielkonflikte und Interdependenzen mit anderen Politikfeldern 5 Rent-Seeking-Aktivitäten in Netzindustrien 5.1 Der „Markt“ für Rent-Seeking-Aktivitäten 5.2 Der „Wettbewerb“ von Interessengruppen 6 Administrative Umsetzung und Evaluierung von Liberalisierungen 7 Fazit
Economy vs. history
(2004)
The aim of this study is to examine in which cases economic forces or historical singularities prevail in the determination of the long-run distribution of firms. We develop a relatively general model of heterogenous firms' location choice in discrete space. The main force towards an agglomerated structure is the reduction of transaction costs for consumers if firms are located closely, whilst competition and transport costs work towards a more disperse structure. We then assess the importance of the initial conditions by simulating and comparing the resulting distribution of firms for identical economic parameters but varying initial settings. If the equilibrium distributions of firms are similar we conclude that economic forces have prevailed, while differences in the resulting distributions indicate that 'history' is more important. The (dis)similarity of distributions of firms is calculated by means of a measure, which exhibits a number of desirable features.
In diesem Beitrag wird das optimale Angebot für einen Wohnungsmarkt bestimmt. Die Nachfrage wird dafür aus einem offenen Modell der monozentrischen Stadt hergeleitet. Weiterhin wird davon ausgegangen, dass Wohnungen aufgrund der verschiedenen Standorte und aufgrund weiterer diskreter Wohnungsmerkmale heterogen sind. Der Wohnungsanbieter an einem Standort wird daher als Mehrproduktmonopolist aufgefasst. Als gewinnmaximale Angebotsstruktur zeigt sich, dass unter bestimmten Bedingungen Wohnungen gleichen Typs an verschiedenen Standorten gleich groß sind. Außerdem werden an den jeweiligen Standorten mehrere Wohnungstypen angeboten. Diese beiden Resultate stehen im deutlichen Gegensatz zu Modellen der Neuen Stadtökonomie, wonach an den Standorten jeweils nur ein Wohnungstyp angeboten wird, dessen Größe zudem über die verschiedenen Standorte variiert.
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}
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.
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.
In this thesis we mainly generalize two theorems from Mackaay-Picken and Picken (2002, 2004). In the first paper, Mackaay and Picken show that there is a bijective correspondence between Deligne 2-classes $\xi \in \check{H}^2(M,\mathcal{D}^2)$ and holonomy maps from the second thin-homotopy group $\pi_2^2(M)$ to $U(1)$. In the second one, a generalization of this theorem to manifolds with boundaries is given: Picken shows that there is a bijection between Deligne 2-cocycles and a certain variant of 2-dimensional topological quantum field theories. In this thesis we show that these two theorems hold in every dimension. We consider first the holonomy case, and by using simplicial methods we can prove that the group of smooth Deligne $d$-classes is isomorphic to the group of smooth holonomy maps from the $d^{th}$ thin-homotopy group $\pi_d^d(M)$ to $U(1)$, if $M$ is $(d-1)$-connected. We contrast this with a result of Gajer (1999). Gajer showed that Deligne $d$-classes can be reconstructed by a different class of holonomy maps, which not only include holonomies along spheres, but also along general $d$-manifolds in $M$. This approach does not require the manifold $M$ to be $(d-1)$-connected. We show that in the case of flat Deligne $d$-classes, our result differs from Gajers, if $M$ is not $(d-1)$-connected, but only $(d-2)$-connected. Stiefel manifolds do have this property, and if one applies our theorem to these and compare the result with that of Gajers theorem, it is revealed that our theorem reconstructs too many Deligne classes. This means, that our reconstruction theorem cannot live without the extra assumption on the manifold $M$, that is our reconstruction needs less informations about the holonomy of $d$-manifolds in $M$ at the price of assuming $M$ to be $(d-1)$-connected. We continue to show, that also the second theorem can be generalized: By introducing the concept of Picken-type topological quantum field theory in arbitrary dimensions, we can show that every Deligne $d$-cocycle induces such a $d$-dimensional field theory with two special properties, namely thin-invariance and smoothness. We show that any $d$-dimensional topological quantum field theory with these two properties gives rise to a Deligne $d$-cocycle and verify that this construction is surjective and injective, that is both groups are isomorphic.
In the recent years there are many researchs discussing the effects of trade policy (tariffs, subsidies etc.) in international trade. The results are manifold. Some authors show that trade policy has negative effects on welfare, some spatial economists demonstrate that trade policy can have positive effects on welfare. This paper considers the effects of the trade policy made by both countries participating in international trade in a spatial economic model. It can be showed that trade policy of both trade partners (tariffs of one country and export subsidies of the other country) can improve the world welfare in comparison with free trade.
Inhalt 1 Einführung und Grundlagen 1.1 Problemstellung und Vorgehensweise 1.2 Ordnungsökonomische Systematisierung 1.3 „Neue“ Besonderheitenlehre für Netzindustrien 2 Ansatzpunkte zur Liberalisierung in Netzindustrien 2.1 Liberalisierung durch Privatisierung 2.1.1 Interdependenz von Privatisierung und Marktöffnung 2.1.2 Privatisierungsstufen 2.2 Liberalisierung durch Deregulierung und Re-Regulierung 2.2.1 Abgrenzung des relevanten Marktes: Netzinfrastruktur versus Netzdienstleistungen 2.2.2 Lokalisierung und Kontrolle von Marktmacht bei Netzinfrastruktur 2.3 Modelle zur Gewährleistung eines diskriminierungsfreien Netzzugangs 2.3.1 Verhandelter Netzzugang mit Missbrauchsaufsicht im Sinne der Essential-Facilities-Doktrin 2.3.2 Staatliche Regulierung des Netzzugangs 2.4 Theorie der vertikalen (Des-)Integration 2.4.1 Allokativ-statische, wohlfahrtsökonomische Analyse vertikaler Integration 2.4.2 Institutionenökonomische Analyse vertikaler Integration 2.4.3 Dynamische, wettbewerbsökonomische Analyse vertikaler Integration 2.4.4 Konsequenz: Vertikale Desintegration 3 Institutionelle Ausgestaltung der Wettbewerbsaufsicht 3.1 Systematisierung der Träger und Kompetenzabgrenzung 3.2 Kriterien für eine effiziente Wettbewerbsaufsicht 4 Schlussfolgerungen und intersektoraler Vergleich des Liberalisierungsprozessesin Netzindustrien
Table of contents 1 Introduction 2 Ecological regulation and cost effectiveness 2.1 Climate policy 2.2 Promotion of renewable energies 3 Ecological regulation and security of supply 3.1 Climate policy 3.2 Promotion of renewable energies 4 The German Renewable Energies Act (EEG) 4.1 Objectives 4.2 Design and mechanisms 5 The European emissions trading system (EETS) 5.1 Objectives 5.2 Framework 6 The EEG and the EETS: trade off between ecological objectivesand cost effectiveness, innovation and security of supply? 6.1 EEG 6.2 EETS 6.3 Comparison between the approaches of the EEG and the EETS 7 Conclusions and outlook
Inhalt 1 Einleitung 2 Theoretische Vor- und Nachteile vertikaler Trennung von Netz undTransportbetrieb 3 Ausgangslage in Schweden vor der Bahnreform 4 Ziele der schwedischen Eisenbahnreform 5 Maßnahmen der schwedischen Eisenbahnreform 6 Kritische Würdigung der Reform 6.1 Marktstruktur des schwedischen Eisenbahnverkehrs 6.1.1 Hauptakteure und Eigentumsstruktur 6.1.2 Wettbewerbssituation im schwedischen Eisenbahnverkehr 6.1.3 Finanzierung des schwedischen Eisenbahnsystems 6.2 Marktverhalten der marktbeherrschenden Unternehmen 6.3 Performance des heutigen schwedischen Eisenbahnsystems 7 Fazit
Inhalt 1 Gegenstand der Untersuchung 2 SV aus wirtschaftstheoretischer Sicht:(neoklassische) Umweltökonomik 3 SV aus wirtschaftspolitischer Sicht:(ordoliberale) ordnungspolitische Aspekte 4 SV aus empirischer Sicht 5 Realitätsbezogene Probleme und Lösungsansätze 6 Realitätsnähere Analyse der Effektivität, Effizienz undWettbewerbskonformität von SV 7 Realitätsnähere Analyse der ordnungspolitischen Aspekte 8 Kriterien erfolgreicher SV 9 Aktuelle Problematik: SV versus Emissionsrechtehandel
(De)regulatory interventions frequently have unintended cross- market effects, which may or may not be desirable. We assess the effects of three policies on aggregate variables, in particular real income, from a theoretical perspective. Our results suggest that instruments acting upon wages have only a weak impact on real income, whereas the distribution of income is affected strongly. In contrast, a policy that enhances product market competition is fostering real income, but also impacts strongly on union wages and the distribution of income.
Existing theoretical literature fails to explain the differences between the pay of workers that are covered by union agreements and others who are not. This study aims at closing this gap by a single general- equilibrium approach that integrates a dual labor market and a two- sector product market. Our results suggest that the so called 'union wage gap' is largely determined by the degree of centralization of the bargains, and, to a somewhat lesser extent, by the expenditure share of the unionized sector's goods.
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
Different habitat models were created for the White Stork (Ciconia ciconia) in the region of the former German province of East Prussia (equals app. the current Russian oblast Kaliningrad and the Polish voivodship Warmia-Masuria). Different historical data sets describing the occurrence of the White Stork in the 1930s, as well as selected variables for the description of landscape and habitat, were employed. The processing and modeling of the applied data sets was done with a geographical information system (ArcGIS) and a statistical modeling approach that comes from the disciplines of machine-learning and data mining (TreeNet by Salford Systems Ltd.). Applying historical habitat descriptors, as well as data on the occurrence of the White Stork, models on two different scales were created: (i) a point scale model applying a raster with a cell size of 1 km2 and (ii) an administrative district scale model based on the organization of the former province of East Prussia. The evaluation of the created models show that the occurrence of White Stork nesting grounds in the former East Prussia for most parts is defined by the variables ‘forest’, ‘settlement area’, ‘pasture land’ and ‘proximity to coastline’. From this set of variables it can be assumed that a good food supply and nesting opportunities are provided to the White Stork in pasture and meadows as well as in the proximity to human settlements. These could be seen as crucial factors for the choice of nesting White Stork in East Prussia. Dense forest areas appear to be unsuited as nesting grounds of White Storks. The high influence of the variable ‘coastline’ is most likely explained by the specific landscape composition of East Prussia parallel to the coastline and is to be seen as a proximal factor for explaining the distribution of breeding White Storks. In a second step, predictions for the period of 1981 to 1993 could be made applying both scales of the models created in this study. In doing so, a decline of potential nesting habitat was predicted on the point scale. In contrast, the predicted White Stork occurrence increases when applying the model of the administrative district scale. The difference between both predictions is to be seen in the application of different scales (density versus suitability as breeding ground) and partly dissimilar explanatory variables. More studies are needed to investigate this phenomenon. The model predictions for the period 1981 to 1993 could be compared to the available inventories of that period. It shows that the figures predicted here were higher than the figures established by the census. This means that the models created here show rather a capacity of the habitat (potential niche). Other factors affecting the population size e.g. breeding success or mortality have to be investigated further. A feasible approach on how to generate possible habitat models was shown employing the methods presented here and applying historical data as well as assessing the effects of changes in land use on the White Stork. The models present the first of their kind, and could be improved by means of further data regarding the structure of the habitat and more exact spatially explicit information on the location of the nesting sites of the White Stork. In a further step, a habitat model of the present times should be created. This would allow for a more precise comparison regarding the findings from the changes of land use and relevant conditions of the environment on the White Stork in the region of former East Prussia, e.g. in the light of coming landscape changes brought by the European Union (EU).
It is shown that the ff effect of mean-field magnetohydrodynamics, which consists in the generation of a mean electromotive force along the mean magnetic field by turbulently fluctuating parts of velocity and magnetic field, is equivalent to the simultaneous generation of both turbulent and mean-field magnetic helicities, the generation rates being equal in magnitude and opposite in sign. In the particular case of statistically stationary and homogeneous fluctuations this implies that the ff effect can increase the energy in the mean magnetic field only under the condition that also magnetic helicity is accumulated there.
We report on bifurcation studies for the incompressible Navier-Stokes equations in two space dimensions with periodic boundary conditions and an external forcing of the Kolmogorov type. Fourier representations of velocity and pressure have been used to approximate the original partial differential equations by a finite-dimensional system of ordinary differential equations, which then has been studied by means of bifurcation-analysis techniques. A special route into chaos observed for increasing Reynolds number or strength of the imposed forcing is described. It includes several steady states, traveling waves, modulated traveling waves, periodic and torus solutions, as well as a period-doubling cascade for a torus solution. Lyapunov exponents and Kaplan-Yorke dimensions have been calculated to characterize the chaotic branch. While studying the dynamics of the system in Fourier space, we also have transformed solutions to real space and examined the relation between the different bifurcations in Fourier space and toplogical changes of the streamline portrait. In particular, the time-dependent solutions, such as, e.g., traveling waves, torus, and chaotic solutions, have been characterized by the associated fluid-particle motion (Lagrangian dynamics).
Projection methods based on wavelet functions combine optimal convergence rates with algorithmic efficiency. The proofs in this paper utilize the approximation properties of wavelets and results from the general theory of regularization methods. Moreover, adaptive strategies can be incorporated still leading to optimal convergence rates for the resulting algorithms. The so-called wavelet-vaguelette decompositions enable the realization of especially fast algorithms for certain operators.
The bifurcation behaviour of the 3D magnetohydrodynamic equations has been studied for external forcings of varying degree of helicity. With increasing strength of the forcing a primary non-magnetic steady state loses stability to a magnetic periodic state if the helicity exceeds a threshold value and to different non-magnetic states otherwise.
Es gibt aus unserer Sicht eine Reihe von Gründen, sich in der gewerkschaftlichen Bildungsarbeit von der Dominanz des Lehrplans abzuwenden und sich an Stelle dessen dem Lernenden in einer Weise zuzuwenden, die seine Deutungen, seine Handlungsmotive und seine Lerninteressen in den Vordergrund stellt. Für den Bildungspraktiker ergeben sich Gründe vor allem aus der wiederholten Erfahrung von Diskrepanzen. Erstens die Diskrepanzen, die zwischen der Definition von Lehrzielen und ihrem Erreichen in der Erwachsenenbildung bestehen. Zweitens die Diskrepanzen, die zwischen dem tatsächlich erlernten Wissen und seiner Umsetzung und Anwendung in der Praxis sich auftun. (aus dem Inhalt)
In diesem Beitrag untersuchen wir den Einfluß einer sozioökonomischen Variablen -- die Wertschätzung der Freizeit durch die Haushalte -- auf das innerstädtische Siedlungsverhalten. Die Diskussion dieser Variablen soll zunächst im Rahmen eines Standardmodells der Stadtökonomie erfolgen. Dabei zeigt sich ein eindeutiges Ergebnis: Jene Haushalte, für die die Freizeit einen hohen Nutzen stiftet, siedeln sich am Stadtzentrum an. Danach wenden wir uns der Empirie zu. Am Beispiel Potsdams soll das tatsächliche Siedlungsverhalten der Haushalte aufgezeigt werden. Der Vergleich der Modellergebnisse mit den empirischen Befunden verdeutlicht zum einen, daß die Modelle vermutlich wesentliche Einflußgrößen, die das Siedlungsverhalten bestimmen, nicht erfassen. Zum anderen zeigen die empirischen Ergebnisse die große Bedeutung der singulären, einer allgemeinen Theorie prinzipiell nicht zugänglichen Einflüsse auf die Zusammensetzung und Verteilung der Wohnbevölkerung.
Inhalt 1 Ziele der Liberalisierung von Netzindustrien:Privatisierung staatlicher Monopole und wettbewerbliche Marktöffnung 2 Markt- und wettbewerbstheoretische Aspekte der Netzinfrastruktur 2.1 Netze als Teil der materiellen Infrastruktur 2.2 Netzinfrastruktur als öffentliches Gut oderInstrument der Daseinsvorsorge? 2.3 Netze als natürliche Monopole? 2.3.1 Nutzenrelevante Netzeffekte 2.3.2 Kostenbestimmende Netzeffekte 2.3.3 Wettbewerbspotenziale trotz Wettbewerbsversagen 3 Wettbewerbsökonomische Implikationen für Netzindustrien 3.1 Vertikale Integration in Netzindustrien 3.1.1 Transaktionskosten versus vertikale Integration 3.1.2 Wettbewerbsökonomische Probleme 3.2 Netzzugangsmodelle 3.3 Institutionelle Ausgestaltung der Wettbewerbsaufsicht 4 Fazit
Inhalt 1 Globalisierung und Wettbewerb 1.1 Einzelne Aspekte 1.2 Unterschiedliche Bewertungen 2 Das MacDougall-Kemp-Modelldes institutionellen Wettbewerbs 2.1 Modellprämissen und -implikationen 2.2 Empirische Evidenz 3 Untersuchung weiterer Politikbereiche 3.1 Sozial- und Umweltpolitik 3.2 Wettbewerbspolitik 4 Mängel der betrachteten Ansätze 4.1 Transaktionskosten von Individuen und Unternehmen 4.2 Verhaltensweisen privater und politischer Akteure 5 Wirtschaftspolitische Konsequenzen
Inhalt 1 Einleitung 2 Standortwettbewerb und Race-to-the-bottom 2.1 Theorie des Standortwettbewerbs 2.2 Prozess des Race-to-the-bottom 2.3 Modelltheoretische Fundierung des Race-to-the-bottom 3 Fusionskontrolle als Standortfaktor 4 Instrumentalisierung der Fusionskontrolle im Standortwettbewerb 4.1 Die deutsche Ministererlaubnis 4.2 Race-to-the-bottom im Rahmen der deutschen Ministererlaubnis? 4.3 Restriktive Handhabung der deutschen Ministererlaubnis 4.4 Das Kriterium der internationalen Wettbewerbsfähigkeit in der deutschenMinistererlaubnis 5 Fazit
In der aktuellen Politik ist seit Beginn der neuen Legislaturperiode Subventionsabbau Gegenstand der politischen Auseinandersetzung. Im Zusammenhang mit der so genannten Ökosteuer ist Ende der 1990er Jahre schon einmal eine ausgiebige Diskussion über die Bedeutung von Subventionen im Transportsektor geführt worden. Eine konsequente theoretische Abhandlung zu diesem Thema liefert dabei Bröcker (1998): Er ermittelt die Wirkungen von Subventionen für den Transportsektor im Rahmen eines räumlichen Marktmodells und zeigt für eine spezifische Wettbewerbssituation, dass bei einer von mehreren möglichen Preissetzungsstrategien Subventionen in einem bestimmten Ausmaß nicht nur die Wohlfahrt erhöhen, sondern dass das Ausmaß der wohlfahrtsmaximierenden Subventionen mit etwa 70 % der entfernungsabhängigen Transportkosten durchaus ein hohes Niveau erreicht. In diesem Beitrag werden für eine andere Wettbewerbsform, nämlich Löschwettbewerb, und drei verschiedene Preisstrategien sowohl kurzfristige als langfristige Wohlfahrtseffekte von Subventionen analysiert. Dabei zeigt sich, dass eine kurzfristige Wohlfahrtsmaximierung langfristig die Wohlfahrt sogar mindern kann, während langfristig optimale Subventionen von Fixkosten bestimmt werden.
The present paper is related to the problem of approximating the exact solution to the magnetohydrodynamic equations (MHD). The behaviour of a viscous, incompressible and resistive fluid is exemined for a long period of time. Contents: 1 The magnetohydrodynamic equations 2 Notations and precise functional setting of the problem 3 Existence, uniqueness and regularity results 4 Statement and Proof of the main theorem 5 The approximate inertial manifold 6 Summary
We demonstrate the occurrence of regimes with singular continuous (fractal) Fourier spectra in autonomous dissipative dynamical systems. The particular example in an ODE system at the accumulation points of bifurcation sequences associated to the creation of complicated homoclinic orbits. Two different machanisms responsible for the appearance of such spectra are proposed. In the first case when the geometry of the attractor is symbolically represented by the Thue-Morse sequence, both the continuous-time process and its descrete Poincaré map have singular power spectra. The other mechanism owes to the logarithmic divergence of the first return times near the saddle point; here the Poincaré map possesses the discrete spectrum, while the continuous-time process displays the singular one. A method is presented for computing the multifractal characteristics of the singular continuous spectra with the help of the usual Fourier analysis technique.
An increasing number of applications requires user interfaces that facilitate the handling of large geodata sets. Using virtual 3D city models, complex geospatial information can be communicated visually in an intuitive way. Therefore, real-time visualization of virtual 3D city models represents a key functionality for interactive exploration, presentation, analysis, and manipulation of geospatial data. This thesis concentrates on the development and implementation of concepts and techniques for real-time city model visualization. It discusses rendering algorithms as well as complementary modeling concepts and interaction techniques. Particularly, the work introduces a new real-time rendering technique to handle city models of high complexity concerning texture size and number of textures. Such models are difficult to handle by current technology, primarily due to two problems: - Limited texture memory: The amount of simultaneously usable texture data is limited by the memory of the graphics hardware. - Limited number of textures: Using several thousand different textures simultaneously causes significant performance problems due to texture switch operations during rendering. The multiresolution texture atlases approach, introduced in this thesis, overcomes both problems. During rendering, it permanently maintains a small set of textures that are sufficient for the current view and the screen resolution available. The efficiency of multiresolution texture atlases is evaluated in performance tests. To summarize, the results demonstrate that the following goals have been achieved: - Real-time rendering becomes possible for 3D scenes whose amount of texture data exceeds the main memory capacity. - Overhead due to texture switches is kept permanently low, so that the number of different textures has no significant effect on the rendering frame rate. Furthermore, this thesis introduces two new approaches for real-time city model visualization that use textures as core visualization elements: - An approach for visualization of thematic information. - An approach for illustrative visualization of 3D city models. Both techniques demonstrate that multiresolution texture atlases provide a basic functionality for the development of new applications and systems in the domain of city model visualization.
Our analysis is concerned with the impact of a regionalisation of unemployment insurance (UI) on workers’ preferences, on firms’ profits, and on effciency. The existence and the extent of UI are endogenously derived by maximising an objective function of the state. Three different types of regionalisation are considered which differ with respect to the area the UI objective function is related to, and with respect to the policy variable used to maximise it. It comes to light that workers are always in favour of central UI, while it depends on the type of regionalisation whether or not firms are better off with regional or with central UI. The same somewhat surprising result applies for efficiency.
We examine the effects of regionalising the budget of unemployment insurance (UI) on wages, employment, and on UI parameters, which, for their part, determine the agents’ preferences concerning such a reform. A numerical example shows that, under reasonable assumptions, the intuition that the reform would enhance efficiency and improve the economic situation of agents from the low- unemployment region to the disadvantage of agents from the high- unemployment region is not valid in general.