University of Potsdam

About: University of Potsdam is a education organization based out in Potsdam, Germany. It is known for research contribution in the topics: Population & Computer science. The organization has 9629 authors who have published 26740 publications receiving 759745 citations. The organization is also known as: Universität Potsdam.

Constraints on axionlike particles with H.E.S.S. from the irregularity of the PKS 2155−304 energy spectrum

Abstract: Axionlike particles (ALPs) are hypothetical light (sub-eV) bosons predicted in some extensions of the Standard Model of particle physics. In astrophysical environments comprising high-energy gamma rays and turbulent magnetic fields, the existence of ALPs can modify the energy spectrum of the gamma rays for a sufficiently large coupling between ALPs and photons. This modification would take the form of an irregular behavior of the energy spectrum in a limited energy range. Data from the H. E. S. S. observations of the distant BL Lac object PKS 2155 - 304 (z = 0.116) are used to derive upper limits at the 95% C. L. on the strength of the ALP coupling to photons, g(gamma a) < 2.1 x 10(-11) GeV-1 for an ALP mass between 15 and 60 neV. The results depend on assumptions on the magnetic field around the source, which are chosen conservatively. The derived constraints apply to both light pseudoscalar and scalar bosons that couple to the electromagnetic field.

Indications for a successively triggered rupture growth underlying the 2000 earthquake swarm in Vogtland/NW Bohemia

Abstract: [1] The characteristics of earthquake swarms can neither be described by simple laws nor are the underlying mechanisms presently understood. Swarm activity is often assumed to be caused by an intrusion of fluids into the seismogenic zone. We have studied the earthquake catalog of the large earthquake swarm that occurred in the year 2000 in Vogtland, SE-Germany and NW-Bohemia, an area well known for its episodic swarm generation. We observe a significant decrease of the Gutenberg–Richter b value during the swarm evolution as well as a fractal temporal clustering of the earthquakes. The spatial spreading of the swarm's activity, which is approximately confined to one plane, cannot simply be explained by a process of fluid diffusion. Instead, we observe a simple relationship between the spatial spreading and the seismic moment release, which is in good agreement with empirical relationships derived for tectonically driven earthquakes and theoretical crack growth models. This observation points to a progressively growing main fracture underlying the swarm activity. In addition, we find that the swarm earthquakes themselves trigger aftershocks near the border of their rupture area. The stick-slip behavior of the rupture propagation can be explained by stress transfers and induced fluid flows due to earthquakes in a fluid-permeated critically loaded fault zone. However, during the first phase, the temporal behavior is found to be different, pointing to intrusion of fluids initiating the swarm activity.

Entanglement-enhanced probing of a delicate material system

Abstract: Researchers report the entanglement-enhanced measurement of a delicate material system, in which they non-destructively probe an 85Rb atomic spin ensemble by near-resonant Faraday rotation. They use narrowband, atom-resonant ‘NOON’ states to beat the standard quantum limit of sensitivity by more than five standard deviations, both on a per-photon and a per-damage basis.

The Trans-Ancestral Genomic Architecture of Glycaemic Traits

Abstract: Glycaemic traits are used to diagnose and monitor type 2 diabetes, and cardiometabolic health. To date, most genetic studies of glycaemic traits have focused on individuals of European ancestry. Here, we aggregated genome-wide association studies in up to 281,416 individuals without diabetes (30% non-European ancestry) with fasting glucose, 2h-glucose post-challenge, glycated haemoglobin, and fasting insulin data. Trans-ancestry and single-ancestry meta-analyses identified 242 loci (99 novel; P

Readers of Chinese extract semantic information from parafoveal words.

Abstract: Evidence for semantic preview benefit (PB) from parafoveal words has been elusive for reading alphabetic scripts such as English. Here we report semantic PB for noncompound characters in Chinese reading with the boundary paradigm. In addition, PBs for orthographic relatedness and, as a numeric trend, for phonological relatedness were obtained. Results are in agreement with other research suggesting that the Chinese writing system is based on a closer association between graphic form and meaning than is alphabetic script. We discuss implications for notions of serial attention shifts and parallel distributed processing of words during reading.