Entspannung in der Taiwanstraße? Aus Publikationen taiwanesischer Denkfabriken in der zweiten Jahreshälfte 2008

Nach den Wahlen in Taiwan 2008 und der Ablösung von Pekings »Erzfeind« Chen Shui bian (Demokratische Fortschrittspartei - DPP) durch den China-freundlicheren Ma Ying-jeou (Kuomintang - KMT) bestand die Hoffnung, dass sich die Beziehungen zum Festland verbessern würden. Trotz abgemilderter Rhetorik und vertrauensbildenden Gesten der neuen Regierung Ma gibt die chinesische Führung jedoch der Forderung Taiwans nach mehr internationalem Spielraum nicht nach. Es bleibt also die Frage, ob sich die in Ansätzen erkennbare Entspannung der Beziehungen verstetigt oder ob das mangelnde Entgegenkommen Pekings den innenpolitischen Druck in Taiwan verstärkt und für neue Spannungen in der Taiwanstraße sorgt. (Autorenreferat

Chinas militärische Entwicklung: Modernisierung und Internationalisierung der Streitkräfte

'Anlässlich des 60. Jahrestages der Gründung der Volksrepublik China und der zur Feier dessen durchgeführten, umfangreichen Militärparade am 1. Oktober 2009 wird in der vorliegenden Studie die Entwicklung des chinesischen Militärs - der größten Berufsarmee der Welt - entlang der folgenden Leitfragen untersucht: Welche programmatischen Richtlinien gibt die KPCh für den Verteidigungssektor des wiedererstarkten modernen China vor? Welche strategischen Ziele lassen sich aus den bisherigen Veränderungen ablesen? Wie sind die militärischen Fortschritte politisch einzuordnen und zu bewerten? Welche Rolle spielen dabei die zunehmenden internationalen Aktivitäten der chinesischen Streitkräfte? Es lässt sich feststellen, dass die Modernisierung des Militärs in einen übergreifenden politischen Anpassungsprozess eingeordnet wird, mit dem China den sicherheitspolitischen Gegebenheiten des 21. Jahrhunderts gerecht werden will. Die umfangreichen Kapazitäten aus der Ära des Kalten Krieges werden schrittweise angepasst und qualitativ aufgewertet, um internationale Friedensmissionen sowie humanitäre Hilfseinsätze bewältigen und bei militärischen Konflikten im Zeitalter des informationstechnologischen Wettstreits bestehen zu können. Die Grundausrichtung der Volksbefreiungsarmee ist dabei derzeit noch als eher defensiv zu bewerten, auch wenn im Bereich der Nuklear-, Weltraum-, Luft- und Seestreitkräfte das offensive Potential wächst. Gleichzeitig geht der rasante Anstieg bei Chinas militärischen Fähigkeiten bislang noch nicht mit einer ausreichenden politischen Kommunikation einher. Eine Erhöhung der sicherheits- und militärpolitischen Transparenz durch die chinesische Führung könnte dazu beitragen, Irritationen bei anderen Staaten zu vermeiden.' (Autorenreferat)'The steady rise in China's defence budget over recent years naturally stokes the speculation. From just Dollar 9.8 billion in 1997 it more than quadrupled within a decade, according to the official figures, to reach Dollar 46.8 billion by 2007 (although the proportion of annual GDP rose by just 0.29 percentage points over the same period). Beijing's official defence budget for 2009 is Dollar 70.2 billion, but the real level of Chinese military spending is disputed. Because they leave important expenditures on strategic capabilities and military space programmes unaccounted for, the official figures say little about the actual state of China's armed forces (PLA). The PLA is still a fundamentally defensive force, although its offensive potential is growing in the fields of nuclear weapons and space-based systems, as well as air and naval forces. Military modernisation has progressed furthest in the realm of the strategic forces and the navy, while the greatest deficits remain in the air force, where a lack of force multipliers such as reconnaissance aircraft and aerial refuelling tankers is the main obstacle to greater strength and force projection. The Western arms embargo ensures that the import of such force multipliers and access to the relevant technologies remain restricted. If it is in the interests of the EU and the United States to deny China access to these technologies at least in the short to medium term, the embargo will have to be maintained on key technologies. The rapid expansion of China's military capabilities has not thus far been accompanied by adequate political communication. An increase in transparency on security and military matters could help to reassure other states. Effective international integration would support this process.' (author's abstract)

New Equations of State in Simulations of Core-Collapse Supernovae

We discuss three new equations of state (EOS) in core-collapse supernova simulations. The new EOS are based on the nuclear statistical equilibrium model of Hempel and Schaffner-Bielich (HS), which includes excluded volume effects and relativistic mean-field (RMF) interactions. We consider the RMF parameterizations TM1, TMA, and FSUgold. These EOS are implemented into our spherically symmetric core-collapse supernova model, which is based on general relativistic radiation hydrodynamics and three-flavor Boltzmann neutrino transport. The results obtained for the new EOS are compared with the widely used EOS of H. Shen et al. and Lattimer & Swesty. The systematic comparison shows that the model description of inhomogeneous nuclear matter is as important as the parameterization of the nuclear interactions for the supernova dynamics and the neutrino signal. Furthermore, several new aspects of nuclear physics are investigated: the HS EOS contains distributions of nuclei, including nuclear shell effects. The appearance of light nuclei, e.g., deuterium and tritium is also explored, which can become as abundant as alphas and free protons. In addition, we investigate the black hole formation in failed core-collapse supernovae, which is mainly determined by the high-density EOS. We find that temperature effects lead to a systematically faster collapse for the non-relativistic LS EOS in comparison to the RMF EOS. We deduce a new correlation for the time until black hole formation, which allows to determine the maximum mass of proto-neutron stars, if the neutrino signal from such a failed supernova would be measured in the future. This would give a constraint for the nuclear EOS at finite entropy, complementary to observations of cold neutron stars.Comment: 26 pages, 17 figures. v3: replaced Fig. 1 with the published one, text unchange

Explosive Nucleosynthesis: What we learned and what we still do not understand

This review touches on historical aspects, going back to the early days of nuclear astrophysics, initiated by B$^2$FH and Cameron, discusses (i) the required nuclear input from reaction rates and decay properties up to the nuclear equation of state, continues (ii) with the tools to perform nucleosynthesis calculations and (iii) early parametrized nucleosynthesis studies, before (iv) reliable stellar models became available for the late stages of stellar evolution. It passes then through (v) explosive environments from core-collapse supernovae to explosive events in binary systems (including type Ia supernovae and compact binary mergers), and finally (vi) discusses the role of all these nucleosynthesis production sites in the evolution of galaxies. The focus is put on the comparison of early ideas and present, very recent, understanding.Comment: 11 pages, to appear in Springer Proceedings in Physics (Proc. of Intl. Conf. "Nuclei in the Cosmos XV", LNGS Assergi, Italy, June 2018

Europe and China after Brexit: the 5G question

A decision looms for Britain on 5G and Huawei. London’s choice will signal whether it wishes to stay close to Europe when dealing with Beijing – or to go its own way, writes Janka Oertel (European Council on Foreign Relations)

Equation-of-state constraints and the QCD phase transition in the era of gravitational-wave astronomy

International audienceWe describe a multi-messenger interpretation of GW170817, which yields a robust lower limit on NS radii. This excludes NSs with radii smaller than about 10.7 km and thus rules out very soft nuclear matter. We stress the potential of this type of constraints when future detections become available. For instance, a very similar argumentation may yield an upper bound on the maximum mass of nonrotating NSs. We also discuss simulations of NS mergers, which undergo a first-order phase transition to quark matter. We point out a different dynamical behavior. Considering the gravitational-wave signal, we identify an unambiguous signature of the QCD phase transition in NS mergers. We show that the occurrence of quark matter through a strong first-order phase transition during merging leads to a characteristic shift of the dominant postmerger frequency. The frequency shift is indicative for a phase transition if it is compared to the postmerger frequency which is expected for purely hadronic EoS models. A very strong deviation of several 100 Hz is observed for hybrid EoSs in an otherwise tight relation between the tidal deformability and the postmerger frequency. In future events the tidal deformability will be inferred with sufficient precision from the premerger phase, while the dominant postmerger frequency can be obtained when current detectors reach a higher sensitivity in the high-frequency range within the next years. Finally, we address the potential impact of a first-order phase transition on the electromagnetic counter-part of NS mergers. Our simulations suggest that there would be no significant qualitative differences between a system undergoing a phase transition to quark matter and purely hadronic mergers. The quantitative differences are within the spread which is found between different hadronic EoS models. This implies on the one hand that GW170817 is compatible with a possible transition to quark matter. On the other hand these considerations show that it may not be easy to identify quantitative differences between purely hadronic mergers and events in which quark matter occurs considering solely their electromagnetic counterpart or their nucleosynthesis products