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We investigate the effects of strong color fields and of the associated enhanced intrinsic transverse momenta on the phi-meson production in ultrarelativistic heavy ion collisions at RHIC. The observed consequences include a change of the spectral slopes, varying particle ratios, and also modified mean transverse momenta. In particular, the composition of the production processes of phi-mesons, that is, direct production vs. coalescence-like production, depends strongly on the strength of the color fields and intrinsic transverse momenta and thus represents a sensitive probe for their measurement.
In this paper, I investigate more closely the contribution of modal operators to the semantics of comparatives and I show that there is no need for a maximality or minimality operator. Following Kratzer s (1981, 1991) analysis of modal elements, I assume that the meaning of a modal sentence is dependent on a conversational background and an ordering source. For comparative environments, I demonstrate that the ordering source reduces a set of possible degrees to a single degree that is most (or least) wanted or expected, i.e., maximality and minimality readings of comparative constructions are an effect of the pragmatic meaning of the modal.
Im Rahmen dieser Dissertation wurde die Photophysik und die elektronische Struktur einer Klasse neuartiger Donator-Akzeptor-Ladungstransfer-Komplexe untersucht. Im Wesentlichen bestehen diese Verbindungen aus einem Ferrocen-Donator (Fc) und organischen Akzeptoren, die über B-N-Bindungen verbrückt sind, welche sich bei dieser Art von makromolekularen Systemen spontan bilden. Zentraler Gegenstand dieser Arbeit war die spektroskopische Untersuchung des Metall-zu-Ligand-Ladungstransfers (engl. Abkürzung: MLCT) im elektronischen Anregungszustand dieser kationischen Komplexverbindungen, die im Weiteren als „Fc-B-bpy“-Verbindungen bezeichnet werden. Die vorliegende Arbeit analysiert eine Vielzahl miteinander verwandter Fc-B-bpy-Derivate. Die Arbeit ist gegliedert in 1.) die Analyse der Absorptionsspektren vom UV- bis zum nahen Infrarot-Spektralbereich (250-1000 nm) von Lösungen, dotierten Polymer-Dünnfilmen und Einkristallen, 2.) die zeitaufgelöste optische Spektroskopie des angeregten Zustands auf der Pikosekunden-Zeitskala, 3.) die Analyse elektrochemischer Messungen an Lösungen, und 4.) die Auswertung quantenchemischer Berechnungen. Für die zeitaufgelösten Messungen wurde ein komplexes optisches Spektroskopie-System mit breitbandigen Femtosekunden-Pulsen sowie den entsprechenden zeitaufgelösten Detektionsmethoden (spektral gefilterte Weißlicht-Detektion) aufgebaut. Die Ergebnisse dieser Arbeit beweisen die Existenz eines MLCT-Übergangs mit fast vollständigem Übergang eines Fc-Donator-Elektrons zum B-bpy-Akzeptor bei optischer Anregung. Die vergleichenden Untersuchungen der spektroskopischen Eigenschaften verschiedener Derivate liefern wichtige Information für die Entwicklung neuartiger Derivate, einschließlich verwandter Polymere, mit verbesserten spektroskopischen Eigenschaften. Es wurden transiente Absorptionsmessungen bestimmter Fc-B-bpy-Derivate in Lösung nach gepulster Anregung der MLCT-Bande (bei 500 nm) über einen Zeitbereich von 0,1-1000 ps und einen Wellenlängenbereich von 460-760 nm vorgenommen. Aus den Messergebnissen geht hervor, dass die Relaxation aus dem angeregten MLCT-Zustand in den Grundzustand auf verschiedenen Zeitskalen geschehen kann, welche im Bereich zwischen ~18 und 900 ps liegen. Ein Vergleich verschiedener Derivate mit unterschiedlicher Flexibilität in der Konformation zeigt, dass die Starrheit der Bindungen zwischen Donatoren und Akzeptoren ein wesentlicher Faktor für die Lebensdauer des angeregten Zustands ist. Wenn die Akzeptorgruppen relativ frei rotieren können, ist es der Verbindung möglich, eine Geometrie einzunehmen, von der aus ein effizienter, strahlungsfreier Übergang in den Grundzustand erfolgen kann. Dieser Befund zeigt einen Weg auf, wie neuartige, verwandte Verbindungen mit größerer Lebensdauer das angeregten Zustands synthetisiert werden können, indem darauf geachtet wird, daß eine starre molekulare Architektur zwischen Donator und Akzeptor verwirklicht wird.
Invited talk at the International Workshop XXX on Gross Properties of Nuclei and Nuclear Excitations - Ultrarelativistic Heavy-Ion Collisions, Jan. 13-19, 2002, Hirschegg, Austria. Report-no: LBNL-49674. We discuss predictions for the pion and kaon interferometry measurements in relativistic heavy ion collisions at SPS and RHIC energies. In particular, we confront relativistic transport model calculations that include explicitly a first-order phase transition from a thermalized quark-gluon plasma to a hadron gas with recent data from the RHIC experiments. We critically examine the "HBT-puzzle" both from the theoretical as well as from the experimental point of view. Alternative scenarios are briefly explained.
Invited talk at the XXXIII International Symposium on Multiparticle Dynamics, Krakow, Poland, 5-11 Sept, 2003. 5 pages, 1 figure Journal-ref: Acta Phys.Polon. B35 (2004) 23-28. We review the recent developments on microscopic transport calculations for two-particle correlations at low relative momenta in ultrarelativistic heavy ion collisions at RHIC.
Invited talk at the 7th International Conference on Strangeness in Quark Matter, SQM 2003, Atlantic Beach, North Carolina, USA, 12-17 Mar, 2003. 11 pages, 12 figures. Journal-ref: J.Phys. G30 (2004) S139-S150. We review recent developments in the field of microscopic transport model calculations for ultrarelativistic heavy ion collisions. In particular, we focus on the strangeness production, for example, the phi-meson and its role as a messenger of the early phase of the system evolution. Moreover, we discuss the important e ects of the (soft) field properties on the multiparticle system. We outline some current problems of the models as well as possible solutions to them
The wide-area deployment of WiFi hot spots challenges IP access providers. While new profit models are sought after by them, profitability as well as logistics for large-scale deployment of 802.11 wireless technology are still to be proven. Expenditure for hardware, locations, maintenance, connectivity, marketing, billing and customer care must be considered. Even for large carriers with infrastructure, the deployment of a large-scale WiFi infrastructure may be risky. This paper proposes a multi-level scheme for hot spot distribution and customer acquisition that reduces financial risk, cost of marketing and cost of maintenance for the large-scale deployment of WiFi hot spots.
Despite the apparent stability of the wage bargaining institutions in West Germany, aggregate union membership has been declining dramatically since the early 90's. However, aggregate gross membership numbers do not distinguish by employment status and it is impossible to disaggregate these sufficiently. This paper uses four waves of the German Socioeconomic Panel in 1985, 1989, 1993, and 1998 to perform a panel analysis of net union membership among employees. We estimate a correlated random effects probit model suggested in Chamberlain (1984) to take proper account of individual specfic effects. Our results suggest that at the individual level the propensity to be a union member has not changed considerably over time. Thus, the aggregate decline in membership is due to composition effects. We also use the estimates to predict net union density at the industry level based on the IAB employment subsample for the time period 1985 to 1997. JEL - Klassifikation: J5
The paper analyses the financial structure of German inward FDI. From a tax perspective, intra-company loans granted by the parent should be all the more strongly preferred over equity the lower the tax rate of the parent and the higher the tax rate of the German affiliate. From our study of a panel of more than 8,000 non-financial affiliates in Germany, we find only small effects of the tax rate of the foreign parent. However, our empirical results show that subsidiaries that on average are profitable react more strongly to changes in the German corporate tax rate than this is the case for less profitable firms. This gives support to the frequent concern that high German taxes are partly responsible for the high levels of intracompany loans. Taxation, however, does not fully explain the high levels of intra-company borrowing. Roughly 60% of the cross-border intra-company loans turn out to be held by firms that are running losses. JEL - Klassifikation H25 , F23 .
This paper is a draft for the chapter German banks and banking structure of the forthcoming book The German financial system . As such, the paper starts out with a description of past and present structural features of the German banking industry. Given the presented empirical evidence it then argues that great care has to be taken when generalising structural trends from one financial system to another. Whilst conventio nal commercial banking is clearly in decline in the US, it is far from clear whether the dominance of banks in the German financial system has been significantly eroded over the last decades. We interpret the immense stability in intermediation ratios and financing patterns of firms between 1970 and 2000 as strong evidence for our view that the way in which and the extent to which German banks fulfil the central functions for the financial system are still consistent with the overall logic of the German financial system. In spite of the current dire business environment for financial intermediaries we do not expect the German financial system and its banking industry as an integral part of this system to converge to the institutional arrangements typical for a market-oriented financial system. This Version: March 25, 2003
Initiated by the seminal work of Diamond/Dybvig (1983) and Diamond (1984), advances in the theory of financial intermediation have sharpened our understanding of the theoretical foundations of banks as special financial institutions. What makes them "unique" is the combination of accepting deposits and issuing loans. However, in recent years the notion of "disintermediation" has gained tremendous popularity, especially among American observers. These observers argue that deregulation, globalisation and advances in information technology have been eroding the role of banks as intermediaries and thus their alleged uniqueness. It is even assumed that ever more efficiently organised capital markets and specialised financial institutions that take advantage of these markets, such as mutual funds or finance companies, will lead to the demise of banks. Using a novel measurement concept based on intermediation and securitisation ratios, the present article provides evidence which shows that banking disintermediation is indeed a reality for the US financial system. This seems to indicate that American banks are not all that "unique"; they can be replaced to a considerable extent. Moreover, many observers seem to believe that what has happened in the US reflects a universal trend. However, empirical results reported in this paper indicate that such a trend has not manifested itself in other financial systems, and in particular, not in Germany or Japan. Evidence on the enormous structural differences between financial systems and the lack of unequivocal signs of convergence render any inferences from the American experience to other financial systems very problematic.
Abstract: It is commonplace in the debate on Germany's labor market problems to argue that high unemployment and low wage dispersion are related. This paper analyses the relationship between unemployment and residual wage dispersion for individuals with comparable attributes. In the conventional neoclassical point of view, wages are determined by the marginal product of the workers. Accordingly, increases in union minimum wages result in a decline of residual wage dispersion and higher unemployment. A competing view regards wage dispersion as the outcome of search frictions and the associated monopsony power of the firms. Accordingly, an increase in search frictions causes both higher unemployment and higher wage dispersion. The empirical analysis attempts to discriminate between the two hypotheses for West Germany analyzing the relationship between wage dispersion and both the level of unemployment as well as the transition rates between different labor market states. The findings are not completely consistent with either theory. However, as predicted by search theory, one robust result is that unemployment by cells is not negatively correlated with the within cell wage dispersion.
This paper evaluates the effects of Public Sponsored Training in East Germany in the context of reiterated treatments. Selection bias based on observed characteristics is corrected for by applying kernel matching based on the propensity score. We control for further selection and the presence of Ashenfelter's Dip before the program with conditional difference-in-differences estimators. Training as a first treatment shows insignificant effects on the transition rates. The effect of program sequences and the incremental effect of a second program on the reemployment probability are insignificant. However, the incremental effect on the probability to remain employed is slightly positive. JEL - Klassifikation: H43 , C23 , J6 , J64 , C14
Central wage bargaining and local wage flexibility : evidence from the entire wage distribution
(1998)
We argue that in labor markets with central wage bargaining wage flexibility varies systematically across the wage distribution: local wage flexibility is more relevant for the upper part of the wage distribution, and flexibility of wages negotiated under central wage bargaining affects the lower part of the wage distribution. Using a random sample of German social-security accounts, we estimate wage flexibility across the wage distribution by means of quantile regressions. The results support our hypothesis, as employees with low wages have significantly lower local wage flexibility than high wage employees. This effect is particularly relevant for the lower educational groups. On the other hand, employees with low wages tend to have a higher wage flexibility with respect to national unemployment.
The Box-Cox quantile regression model using the two stage method introduced by Chamberlain (1994) and Buchinsky (1995) provides an attractive extension of linear quantile regression techniques. However, a major numerical problem exists when implementing this method which has not been addressed so far in the literature. We suggest a simple solution modifying the estimator slightly. This modification is easy to implement. The modified estimator is still [square root] n-consistent and its asymptotic distribution can easily be derived. A simulation study confirms that the modified estimator works well.
This paper investigates the magnitude and the main determinants of share price reactions to buy-back announcements of German corporations. For our comprehensive sample of 224 announcements that took place between May 1998 and April 2003 we find average cumulative abnormal returns around -7.5% for the thirty days preceding the announcement and around +7.0 % for the ten days following the announcement. We regress post-announcement abnormal returns with multiple firm characteristics and provide evidence which supports the undervaluation signaling hypothesis but not the excess cash hypothesis or the tax-efficiency hypothesis. In extending prior empirical work, we also analyze price effects from initial statements of firms that they intend to seek shareholder approval for a buy-back plan. Observed cumulative abnormal returns on this initial date are in excess of 5% implying a total average price effect between 12% and 15% from implementing a buy-back plan. We conjecture that the German regulatory environment is the main reason why market variations to buy-back announcements are much stronger in Germany than in other countries and conclude that initial statements by managers to seek shareholders’ approval for a buy-back plan should also be subject to legal ad-hoc disclosure requirements.
This paper shows that abnormal stock price returns around open market repurchase announcements are about four times higher in Germany than in the US (12% versus 3%). We hypothesize that this observation can be explained by country differences in repurchase regulation. Our empirical evidence indicates that German managers primarily buy back shares to signal an undervaluation of their firm. We demonstrate that the stringent repurchase process prescribed by German law attributes a higher credibility to such a signal than lax US regulations and thereby corroborate our hypothesis.
This paper analyzes empirically the distribution of unemployment durations in West- Germany before and after the changes during the mid 1980s in the maximum entitlement periods for unemployment benefits for elderly unemployed. The analysis is based on the comprehensive IAB employment subsample containing register panel data for about 500.000 individuals in West Germany. We analyze two proxies for unemployment since the data do not precisely measure unemployment in an economic sense. We provide a theoretical analysis of the link between the durations of nonemployment and of unemployment between jobs. Our empirical analysis finds significant changes in the distributions of nonemployment durations for older unemployed individuals. At the same time, the distribution of unemployment durations between jobs did not change in response to the reforms. Our findings are consistent with an interpretation that many firms and workers used the more bene cial laws as a part of early retirement packages but those workers who were still looking for a job did not reduce their search effort in response to the extension of the maximum entitlement periods. This interpretation is consistent with our theoretical model under plausible assumptions. JEL: C24, J64, J65
This paper examines intraday stock price effects and trading activity caused by ad hoc disclosures in Germany. The evidence suggests that the observed stock prices react within 90 minutes after the ad hoc disclosures. Trading volumes take even longer to adjust. We find no evidence for abnormal price reactions or abnormal trading volume before announcements. The bigger the company that announces an ad hoc disclosure, the less severe is the abnormal price effect following the announcement. The number of analysts is negatively correlated to the trading volume effect before the ad hoc disclosure. The higher the trading volume on the last trading day before the announcement, the greater is the price effect after the ad hoc disclosures and the greater the trading volume effect. Keywords: ad hoc disclosure rules, intraday stock price adjustments, market efficiency.