Half-lives of rp-process waiting point nuclei

We give results of microscopic calculations for the half-lives of various proton-rich nuclei in the mass region A=60-90, which are involved in the astrophysical rp-process, and which are needed as input parameters of numerical simulations in Nuclear Astrophysics. The microscopic formalism consists of a deformed QRPA approach that involves a selfconsistent quasiparticle deformed Skyrme Hartree-Fock basis and residual spin-isospin separable forces in both the particle-hole and particle-particle channels. The strength of the particle-hole residual interaction is chosen to be consistent with the Skyrme effective force and mean field basis, while that of the particle-particle is globally fixed to 0.07 MeV after a judicious choice from comparison to experimental half-lives. We study and discuss the sensitivity of the half-lives to deformation and residual interactions.Comment: 8 pages, 4 figures, to be published in Eur. Phys. J.

Tachyon Condensation in Large Magnetic Fields with Background Independent String Field Theory

We discuss the problem of tachyon condensation in the framework of background independent open string field theory. We show, in particular, that the computation of the string field theory action simplifies considerably if one looks at closed string backgrounds with a large B field, and can be carried out exactly for a generic tachyon profile. We confirm previous results on the form of the exact tachyon potential, and we find, within this framework, solitonic solutions which correspond to lower dimensional unstable branes.Comment: 10 pages, some references added and minor imprecisions correcte

Mobilizing youth in the 21st century: How digital media use fosters civic duty, information efficacy, and political participation

Youth turnout at European Parliamentary elections has been dwindling. This study investigates the impact of news media exposure on electoral participation of first time voters. Relying on a data set that combines content analysis of news stories about the EU (N = 769) and a multiple wave panel survey (N = 994), we analyze the impact of exposure to online and offline coverage of relevant topics on turn out across a period of 6 months. We find that exposure to news in offline media had no significant effect on participation, whereas exposure to relevant news in online media positively affected turnout

Cross road elections: Change in EU performance evaluations during the European Parliament elections 2014

The 2014 European Parliament (EP) elections were held after a period where public opinion about the EU changed significantly. In this paper we investigate evaluations of the performance of the European Union, as this dimension of EU attitudes is particularly relevant ahead of elections. We look at public opinion developments since 2009 and then zoom in on the role played by the news media in shaping public opinion about EU performance by linking citizens’ evaluations across time to the news media content they were exposed to. The article relies on original multiple wave survey panel data and a systematic media content analysis in the Netherlands. It shows how public opinion has changed, how it changes around EP elections, and how exposure to media coverage can help improve citizens’ evaluations of EU performance

Tachyon cosmology with non-vanishing minimum potential: a unified model

We investigate the tachyon condensation process in the effective theory with non-vanishing minimum potential and its implications to cosmology. It is shown that the tachyon condensation on an unstable three-brane described by this modified tachyon field theory leads to lower-dimensional branes (defects) forming within a stable three-brane. Thus, in the cosmological background, we can get well-behaved tachyon matter after tachyon inflation, (partially) avoiding difficulties encountered in the original tachyon cosmological models. This feature also implies that the tachyon inflated and reheated universe is followed by a Chaplygin gas dark matter and dark energy universe. Hence, such an unstable three-brane behaves quite like our universe, reproducing the key features of the whole evolutionary history of the universe and providing a unified description of inflaton, dark matter and dark energy in a very simple single-scalar field model.Comment: 18 p

A perturbative analysis of tachyon condensation

Tachyon condensation in the open bosonic string is analyzed using a perturbative expansion of the tachyon potential around the unstable D25-brane vacuum. Using the leading terms in the tachyon potential, Pad\'e approximants can apparently give the energy of the stable vacuum to arbitrarily good accuracy. Level-truncation approximations up to level 10 for the coefficients in the tachyon potential are extrapolated to higher levels and used to find approximants for the full potential. At level 14 and above, the resulting approximants give an energy less than -1 in units of the D25-brane tension, in agreement with recent level-truncation results by Gaiotto and Rastelli. The extrapolated energy continues to decrease below -1 until reaching a minimum near level 26, after which the energy turns around and begins to approach -1 from below. Within the accuracy of this method, these results are completely consistent with an energy which approaches -1 as the level of truncation is taken to be arbitrarily large.Comment: 8 pages, 3 eps figures, Latex; v2: typo correcte

The influence of shock pressure, pre-shock temperature, and host rock composition on the survival rate of endolithic microorganisms during impact ejection from Mars

Petrographic and biological analysis of shock recovery experiments confirms the possible life transport due to an impact from Mars to Earth