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Many methods have been proposed for the stabilization of higher index differential-algebraic equations (DAEs). Such methods often involve constraint differentiation and problem stabilization, thus obtaining a stabilized index reduction. A popular method is Baumgarte stabilization, but the choice of parameters to make it robust is unclear in practice. Here we explain why the Baumgarte method may run into trouble. We then show how to improve it. We further develop a unifying theory for stabilization methods which includes many of the various techniques proposed in the literature. Our approach is to (i) consider stabilization of ODEs with invariants, (ii) discretize the stabilizing term in a simple way, generally different from the ODE discretization, and (iii) use orthogonal projections whenever possible. The best methods thus obtained are related to methods of coordinate projection. We discuss them and make concrete algorithmic suggestions.
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)
Im vorliegenden Beitrag wird an Hand dreier Beispiele der Einsatz von optischer Sensorik zur Produktcharakterisierung dargestellt, nämlich Untersuchungen zum O2-Gehalt in Fruchtsäften, zur Isotopiesignatur von CO2 in Mineralwässern und zu Lichtstreueigenschaften eines Sonnenschutzmittels. Inhalt: Bestimmung von O2 mit Lumineszenzsonden Isotopenselektive Bestimmung von CO2 mit TDLAS Optische Charakterisierung stark streuender Materialien mit Photonendichtewellen
An approach to the development of fluorescent probes to follow polymerizations in situ using fluorinated cross-conjugated enediynes (Y-enynes) is reported. Different substitution patterns in the Y-enynes result in distinct solvatochromic behavior. β,β-Bis(phenylethynyl)pentafluorostyrene 7, which bears no donor substituents and only fluorine at the styrene moiety, shows no solvatochromism. Donor substituted β,β-bis(3,4,5-trimethoxyphenylethynyl) pentafluorostyrene 8 and β,β-bis(4-butyl-2,3,5,6-tetrafluorophenylethynyl)-3,4,5-trimethoxystyrene 9 exhibit solvatochromism upon change of solvent polarity. Y-enyne 8 showed the largest solvatochromic shift (94 nm bathochromic shift) upon changing solvent from cyclohexane to acetonitrile. A smaller solvatochromic response (44 nm bathochromic shift) was observed for 9. Lippert–Mataga treatment of 8 and 9 yields slopes of -10,800 and -6,400 cm -1, respectively. This corresponds to a change in dipole moment of 9.6 and 6.9 D, respectively. The solvatochromic behavior in 8 and 9 supports the formation of an intramolecular charge transfer (ICT) state. The low fluorescence quantum yields are caused by competitive double bond rotation. The fluorescence decay time of 9 decreases in methyltetrahydrofuran from 2.1 ns at 77 K to 0.11 ns at 200 K. Efficient single bond rotation in 9 was frozen at -50 °C in a configuration in which the trimethoxyphenyl ring is perpendicular to the fluorinated rings. 7–9 are photostable compounds. The X-ray structure of 7 shows it is not planar and that its conjugation is distorted. Y-enyne 7 stacks in the solid state showing coulombic, actetylene–arene, and fluorine–π interactions.
Investigations with frequency domain photon density waves allow elucidation of absorption and scattering properties of turbid media. The temporal and spatial propagation of intensity modulated light with frequencies up to more than 1 GHz can be described by the P1 approximation to the Boltzmann transport equation. In this study, we establish requirements for the appropriate choice of turbid model media and characterize mixtures of isosulfan blue as absorber and polystyrene beads as scatterer. For these model media, the independent determination of absorption and reduced scattering coefficients over large absorber and scatterer concentration ranges is demonstrated with a frequency domain photon density wave spectrometer employing intensity and phase measurements at various modulation frequencies.
Die Anwendung von optischen Parametern zur Stoffcharakterisierung wird diskutiert. Dabei ist der Schwerpunkt der Diskussion auf absorptions- und fluoreszenzspektroskopische Methoden gesetzt. Beide Methoden können schnell und zuverlässig – auch im on-line Betrieb – eingesetzt werden. Der Beitrag soll einen Überblick über die grundlegenden Möglichkeiten der Anwendung beider Methoden geben.
China ist auf dem Weg zu einer offeneren Gesellschaft mit zunehmender Partizipation, größerer rechtlicher Sicherheit und individueller Autonomie. Der Staat zog sich aus vielen Bereichen zurück, ökonomische Ziele bestimmen seine Prioritäten. Die Entwicklungserfolge brachten jedoch eine Legitimationskrise des Staates mit sich. Vier Dilemmata, die China heute konfrontieren, werden aufgezeigt und Hypothesen zur Charakterisierung des chinesischen party state diskutiert.
Chinas Wandel und die Welt
(2006)
Wie stellt sich das Verhältnis zwischen China und der Welt im 21. Jahrhundert dar? Die Autorin, Politikwissenschaftlerin aus Peking, verweist auf die aktuelle Debatte in China, in der das Primat der Innenpolitik, regionaler Multilateralismus und harmonische Weltordnung intensiv diskutiert werden. China habe nicht vor, das internationale System herauszufordern oder zu zerstören. Vielmehr sei es um stärkere Einbindung bemüht.
First studies of electron transfer in [N]phenylenes were performed in bimolecular quenching reactions of angular [3]- and triangular [4]phenylene with various electron acceptors. The relation between the quenching rate constants kq and the free energy change of the electron transfer (ΔG0CS ) could be described by the Rehm-Weller equation. From the experimental results, a reorganization energy λ of 0.7 eV was derived. Intramolecular electron transfer reactions were studied in an [N]phenylene bichomophore and a corresponding reference compound. Fluorescence lifetime and quantum yield of the bichromophor display a characteristic dependence on the solvent polarity, whereas the corresponding values of the reference compound remain constant. From the results, a nearly isoenergonic ΔG0CS can be determined. As the triplet quantum yield is nearly independent of the polarity, charge recombination leads to the population of the triplet state.
According to the author, chairman of the Foreign Policy Committee in the German parliament (Bundestag), German foreign policy is based on a strong parliamentary consensus: continuing as a Western European country, co-operating with our partners in the European Union and the NATO, acting as a responsible member of UN and OSCE. Germany firmly stands up to these basic decisions, also today in a changed world, concentrating on reaching two major goals: building up a new security architecture for Europe as a whole and reuniting Europe by enlarging the European Union. Moderate and co-operate in style, Germany will continue to be a reliable partner, willing and ready to accept even more responsibilities in Europe and beyond Europe.
The ten-years presidency of Alberto Fujimori in Peru is a classic example of the sort of hybrid democracy that emerged in various Latin American countries in the 1990s, combining a mixture of democratic and clearly non-democratic elements. Fujimori was one of the more autocratic Latin American leaders of the 1990s, he is being the only regime formally to break with pre-existing constitutional rules. Closely tied to the military and intelligence apparatus, his government involved a concentration of political power that reduced the scope and autonomy of other branches of the state. But, unlike previous Latin American military dictatorships, Fujimori’s government enjoyed a considerable popularity, born out of disaffection for representative institutions. The article argues, however, that these characteristics of apparent strength carried within them the seeds of their own destruction. Far from establishing lasting political stability, the regime was weakly based. Within six weeks of his inauguration for a third term in July 2000, Fujimori was obliged to announce his intention to withdraw from politics. Two months later, he was ousted altogether.
After the democratic euphoria of the early 1990s, today the "third wave of democratization" seems to be less a triumph of political liberalism and much more a success story of a "defective" form of democracy. The authors argue that none of the strategies which can be found in contemporary democratization studies is satisfactory. They offer an alternative two-step-strategy of (1) specifying the root concept of democracy and (2) building subtypes of democracy which are based on this specified root concept. In doing so, the authors conceptualize the model of embedded democracy, from which they generate the concept of "defective democracy" and present a typology of these "defective democracies".
While at the time of Goethe, Turkey and other parts of the world seemed to be far away. Today’s Germany is confronted with the pressure of globalization. With regard to environmental issues or the threat of terrorism, international co-operation and combined efforts are strongly demanded. Unfortunately, the German higher education system is not prepared to face these challenges. The article calls for the education of an elite at German universities, which is fit to work in national as well in international institutions. The author presents the Master’s of International Relations coursework at the Technical University of Dresden.
Confronted with new dimensions of international problems, Germany needs a new foreign policy elite that is able to deal with the pending challenges in world politics. Therefore, the author points out, it is necessary to reorganize the German way to recruit personal for international tasks and the manner of its education at German universities. Furthermore, the German society should revise its general hostile attitude towards the elite and recognize it as an important driving force in politics.
The author detects some of the causes for the less than satisfactory representation of the German foreign policy elite on the international level within the German university structure. The article also reflects upon the issue of the 'content' of a possible and desirable German 'Weltpolitik' which is seen in Global Public Policy - an example of which is provided and reasons given for the ability of the German elite to be proactively engaged in the promotion and management of Global Public Policy Networks.
The security policy of Pakistan is aimed at a reduction of nuclear threats in the South Asian region. It is only natural, that a state, whose national security is endangered by a mighty neighbor, will have to strengthen its defense capacities. Unfortunately, the effective collective measures to prevent and to remove threats to peace and international security as laid down in the Charter of the United Nations prove to be an unreliable promise. Ever since India carried out its first nuclear tests in 1974, Pakistan has been forced into a race to catch up with the capabilities if its neighbor. Nevertheless, Pakistan chose a minimalist approach and refrained from converting its nuclear capabilities into weapon systems. Pakistan is against an arms race in the South Asian region, and opposes the concept of first use of nuclear weapons. To ensure lasting peace, a common vision on disarmament is necessary.
The comprehensive transformation after the breakdown of communist rule was also reflected in a profound change in national policies. The dominating approach in the days of the old regime were grounded in the concept of a single nation state. The years since 1989 witnessed a rise of new democratic attitudes towards national and ethnic minorities. National minorities make up 3 to 4% of the population. Their total number is estimated to be approximately 1.0 to 1.3 Million people. Contemporary national policy rejects the principle of assimilation (polonization) of national and ethnic minorities while supporting their integration.
The Bush Administration supported, earlier than some West European NATO partners, the reunification of the two German states. When the crisis of the political system in East Germany escalated in 1989, the US-government tried to link the support for far-reaching democratic reforms with a rapid involvement of all NATO members in the unification strategy of the Bonn government. For the Bush administration, the most complicated task was to convince the Moscow leadership that a loss of the GDR as a strategic domain in the Central Europe, and NATO membership of a united Germany, would not undermine security interests of the Soviet Union. At the End of the East-West-Conflict, German unification was in full accordance with the global strategic interests of the United States.
The end of the Cold War opened a window for a new era in world security. Instead of rising to this extraordinary occasion, the United States has adopted a regressive Great Power approach to military security. Rather than promote 'win-win' solutions for peace, security, disarmament, and democracy, it treats international security as a 'zero-sum' game. This article discusses examples in the areas of military spending, military research and development, and arms production and export. It also looks at US policy regarding the use of force, including the role of the United Nations, military intervention in other nations, military alliances, and multilateral military action. In conclusion, the article comments on whether we can expect more constructive action under a new administration and congress.
Ghana’s local government system has been subject to various reform attempts which all involved some sort of decentralisation. This article tries to link decentralisation to changing national policy frames and the various governments’ need to maintain political control. Consequently, decentralisation becomes a dependent variable of the so called bureaucratic development state. After a brief discussion of the colonial and post-colonial local government system in Ghana, emphasis is placed on the crisis of the post colonial state and the emergence of a new local government system in 1988 - which was successfully transformed into the administrative system of Ghana’s 4th republic after 1992. Local participation has been substantially improved an sustained by the introduction of the District Assemblies Common Fund in 1993 which transfers 5% of the national tax income to the districts.