1,316 research outputs found
The Posting of Luther’s Theses - Legend or Fact?
Less than 10 years ago a discussion began over the posting of Luther\u27s Ninety-five Theses, some doubting that it actually took place on the traditional day of October 31, 1517, some going so far as to contend that the posting never happened and is only a legend. Ten years ago, in the summer of 1957 at the Lutheran World Federation Meeting in Minneapolis, I was one of those who saw a young Sunday school teacher, impersonating Luther, on a float in a parade vigorously nail a copy of the Ninety-five Theses on a stage door depicting the one of Wittenberg. None of us who witnessed this spectacle had the faintest idea that in the course of the next 10 years the posting of these Theses would become so hot a subject of discussion in academic circles and be so vehemently contested as is the case
Analog Simulation of Weyl Particles with Cold Atoms
We study theoretically, numerically, and experimentally the relaxation of a
collisionless gas in a quadrupole trap after a momentum kick. The
non-separability of the potential enables a quasi thermalization of the single
particle distribution function even in the absence of interactions.
Suprinsingly, the dynamics features an effective decoupling between the strong
trapping axis and the weak trapping plane. The energy delivered during the kick
is redistributed according to the symmetries of the system and satisfies the
Virial theorem, allowing for the prediction of the final temperatures. We show
that this behaviour is formally equivalent to the relaxation of massless
relativistic Weyl fermions after a sudden displacement from the center of a
harmonic trap
Magnetic-field dependence of electron spin relaxation in n-type semiconductors
We present a theoretical investigation of the magnetic field dependence of
the longitudinal () and transverse () spin relaxation times of
conduction band electrons in n-type III-V semiconductors. In particular, we
find that the interplay between the Dyakonov-Perel process and an additional
spin relaxation channel, which originates from the electron wave vector
dependence of the electron -factor, yields a maximal at a finite
magnetic field. We compare our results with existing experimental data on
n-type GaAs and make specific additional predictions for the magnetic field
dependence of electron spin lifetimes.Comment: accepted for publication in PRB, minor changes to previous manuscrip
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Atmosphere-ocean coupled processes in the Madden-Julian oscillation
The Madden-Julian oscillation (MJO) is a convectively coupled 30-70 day (intraseasonal) tropical atmospheric mode that drives variations in global weather, but which is poorly simulated in most atmospheric general circulation models. Over the past two decades, field campaigns and modeling experiments have suggested that tropical atmosphere-ocean interactions may sustain or amplify the pattern of enhanced and suppressed atmospheric convection that defines the MJO, and encourage its eastward propagation through the Indian and Pacific Oceans. New observations collected during the past decade have advanced our understand of the ocean response to atmospheric MJO forcing and the resulting intraseasonal sea surface temperature (SST) fluctuations. Numerous modeling studies have revealed a considerable impact of the mean state on MJO ocean-atmosphere coupled processes, as well as the importance of resolving the diurnal cycle of atmosphere--upper-ocean interactions. New diagnostic methods provide insight to atmospheric variability and physical processes associated with the MJO, but offer limited insight on the role of ocean feedbacks. Consequently, uncertainty remains concerning the role of the ocean in MJO theory. Our understanding of how atmosphere-ocean coupled processes affect the MJO can be improved by collecting observations in poorly sampled regions of MJO activity, assessing oceanic and atmospheric drivers of surface fluxes, improving the representation of upper-ocean mixing in coupled-model simulations, designing model experiments that minimize mean-state differences, and developing diagnostic tools to evaluate the nature and role of coupled ocean-atmosphere processes over the MJO cycle
Distinct magneto-Raman signatures of spin-flip phase transitions in CrI
The discovery of 2-dimensional (2D) materials, such as CrI, that retain magnetic ordering at monolayer thickness has resulted in a surge of both pure and applied research in 2D magnetism. Here, we report a magneto-Raman spectroscopy study on multilayered CrI, focusing on two additional features in the spectra that appear below the magnetic ordering temperature and were previously assigned to high frequency magnons. Instead, we conclude these modes are actually zone-folded phonons. We observe a striking evolution of the Raman spectra with increasing magnetic field applied perpendicular to the atomic layers in which clear, sudden changes in intensities of the modes are attributed to the interlayer ordering changing from antiferromagnetic to ferromagnetic at a critical magnetic field. Our work highlights the sensitivity of the Raman modes to weak interlayer spin ordering in CrI
Distinct magneto-Raman signatures of spin-flip phase transitions in CrI3
The discovery of 2-dimensional (2D) materials, such as CrI3, that retain
magnetic ordering at monolayer thickness has resulted in a surge of research in
2D magnetism from both pure and applied perspectives. Here, we report a
magneto-Raman spectroscopy study on multilayered CrI3, focusing on two new
features in the spectra which appear at temperatures below the magnetic
ordering temperature and were previously assigned to high frequency magnons. We
observe a striking evolution of the Raman spectra with increasing magnetic
field in which clear, sudden changes in intensities of the modes are attributed
to the interlayer ordering changing from antiferromagnetic to ferromagnetic at
a critical magnetic field. Our work highlights the sensitivity of the Raman
modes to weak interlayer spin ordering in CrI3. In addition, we theoretically
examine potential origins for the new modes, which we deduce are unlikely
single magnons
In silico screening of the impact of hERG channel kinetic abnormalities on channel block and susceptibility to acquired long QT syndrome
Accurate diagnosis of predisposition to long QT syndrome is crucial for reducing the risk of cardiac arrhythmias. In recent years, drug-induced provocative tests have proved useful to unmask some latent mutations linked to cardiac arrhythmias. In this study we expanded this concept by developing a prototype for a computational provocative screening test to reveal genetic predisposition to acquired long-QT syndrome (aLQTS). We developed a computational approach to reveal the pharmacological properties of I blocking drugs that are most likely to cause aLQTS in the setting of subtle alterations in I channel gating that would be expected to result from benign genetic variants. We used the model to predict the most potentially lethal combinations of kinetic anomalies and drug properties. In doing so, we also implicitly predicted ideal inverse therapeutic properties of K channel openers that would be expected to remedy a specific defect We systematically performed "in silico mutagenesis" by altering discrete kinetic transition rates of the Fink et al. Markov model of human l channels, corresponding to activation, inactivation, deactivation and recovery from inactivation of I-Kr channels. We then screened and identified the properties of IKr blockers that caused acquired long QT and therefore unmasked mutant phenotypes for mild, moderate and severe variants. Mutant I-Kr channels were incorporated into the O'Hara et al. human ventricular action potential (AP) model and subjected to simulated application of a wide variety of I-drug interactions in order to identify the characteristics that selectively exacerbate the AP duration (APD) differences between wild-type and IKr mutated cells. Our results show that drugs with disparate affinities to conformation states of the I-Kr, channel are key to amplify variants underlying susceptibility to acquired long QT syndrome, an effect that is especially pronounced at slow frequencies. Finally, we developed a mathematical formulation of the M54T MiRP1 latent mutation and simulated a provocative test. In this setting, application of dofetilide dramatically amplified the predicted QT interval duration in the M54T hMiRP1 mutation compared to wild-type.This work was partially supported by the "VI Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica" from the Ministerio de Economia y Competitividad of Spain (TIN2012-37546-CO3-01) and the European Commission (European Regional Development Funds - ERDF-FEDER), Programa de Apoyo a la Investigacion y Desarrollo de la Universidad Politecnica de Valencia (PAID-00-10-3212) to L.R., Direccion General de Politica Cientifica de la Generalitat Valenciana (GV/2013/119), and Programa Prometeo de la Conselleria d'Educacio Formacio I Ocupacio, Generalitat Valenciana (PROMETEO/ 2012/030). The research was also supported by the American Heart Association (GIAs (10GRNT3880050, 13GRNT14370019), Western States Affiliate), Alfred P. Sloan Foundation, the National Institutes of Health NHLBI R01-HL-085592 and a research grant from Gilead Sciences (to CEC).Romero Pérez, L.; Trénor Gomis, BA.; Yang, P.; Saiz Rodríguez, FJ.; Clancy, CE. (2014). In silico screening of the impact of hERG channel kinetic abnormalities on channel block and susceptibility to acquired long QT syndrome. Journal of Molecular and Cellular Cardiology. 72:126-137. https://doi.org/10.1016/j.yjmcc.2014.02.018S1261377
Erwartungsbildung über den Wahlausgang und ihr Einfluss auf die Wahlentscheidung
Erwartungen über den Wahlausgang haben einen festen Platz sowohl in Rational-Choice-Theorien des Wählerverhaltens als auch in stärker sozialpsychologisch orientierten Ansätzen. Die Bildung von Erwartungen und ihr Einfluss auf die Wahlentscheidung ist dabei jedoch ein noch relativ unerforschtes Gebiet. In diesem Beitrag werden anhand von Wahlstudien für Belgien, Österreich und Deutschland verschiedene Fragen der Erwartungsbildung und ihrer Auswirkungen untersucht. Zunächst wird die Qualität der Gesamterwartungen analysiert und verschiedene Faktoren identifiziert, die einen systematischen Einfluss auf die Erwartungsbildung haben. Im zweiten Schritt wenden wir uns den Einzelerwartungen über verschiedene Parteien und Koalitionen zu und finden eine moderate Verzerrung zugunsten der präferierten Parteien und Koalitionen. Dabei kann gezeigt werden, dass der Effekt des Wunschdenkens mit dem politischen Wissen und dem Bildungsgrad abnimmt. Schließlich werden in einem letzten Schritt zwei unterschiedliche Logiken für die Auswirkungen von Erwartungen getestet, das rationale Kalkül des koalitionsstrategischen Wählens zur Vermeidung der Stimmenvergeudung sowie der sozialpsychologisch begründete Bandwagon-Effekt. Das Ausmaß an politischem Wissen scheint dabei eine zentrale vermittelnde Variable zwischen den beiden Logiken zu sein
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