Laser-induced solid-solid phase transition in As under pressure: A theoretical prediction

In Arsenic a pressure-induced solid-solid phase transition from the A7 into the simple cubic structure has been experimentally demonstrated [Beister et al., Phys. Rev. B 41, 5535 (1990)]. In this paper we present calculations, which predict that this phase transition can also be induced by an ultrashort laser pulse in As under pressure. In addition, calculations for the pressure-induced phase transition are presented. Using density functional theory in the generalized gradient approximation, we found that the pressure-induced phase transition takes place at 26.3 GPa and is accompanied by a volume change "Delta V" = 0.5 bohr^3/atom. The laser-induced phase transition is predicted for an applied pressure of 23.8 GPa and an absorbed laser energy of 2.8 mRy/atom.Comment: 9 pages, 5 figures Changes to content To be published in New Journal of Physics (accepted for publication

Metatranscriptomic Sequencing of a Cyanobacterial Soil-Surface Consortium with and without a Diverse Underlying Soil Microbiome.

Soil surface consortia are easily observed and sampled, allowing examination of their interactions with soil microbiomes. Here, we present metatranscriptomic sequences from Dark Green 1 (DG1), a cyanobacterium-based soil surface consortium, in the presence and absence of an underlying soil microbiome and/or urea

Evaluation of a Sr+ 88 Optical Clock with a Direct Measurement of the Blackbody Radiation Shift and Determination of the Clock Frequency

We report on an evaluation of an optical clock that uses the S21/2→D25/2 transition of a single Sr+88 ion as the reference. In contrast to previous work, we estimate the effective temperature of the blackbody radiation that shifts the reference transition directly during operation from the corresponding frequency shift and the well-characterized sensitivity to thermal radiation. We measure the clock output frequency against an independent Yb+171 ion clock, based on the S21/2(F=0)→F27/2(F=3) electric octupole (E3) transition, and determine the frequency ratio with a total fractional uncertainty of 2.3×10-17. Relying on a previous measurement of the Yb+171 (E3) clock frequency, we find the absolute frequency of the Sr+88 clock transition to be 444 779 044 095 485.277(59) Hz. Our result reduces the uncertainty by a factor of 3 compared with the previously most accurate measurement and may help to resolve so far inconsistent determinations of this value. We also show that for three simultaneously interrogated Sr+88 ions, the increased number causes the expected improvement of the short-term frequency instability of the optical clock without degrading its systematic uncertainty

Coherent Excitation of the Highly Forbidden Electric Octupole Transition in Yb+ 172

We report on the first coherent excitation of the highly forbidden S21/2?F27/2 electric octupole (E3) transition in a single trapped Yb+172 ion, an isotope without nuclear spin. Using the transition in Yb+171 as a reference, we determine the transition frequency to be 642 116 784 950 887.6(2.4) Hz. We map out the magnetic field environment using the forbidden S21/2?D25/2 electric quadrupole (E2) transition and determine its frequency to be 729 476 867 027 206.8(4.4) Hz. Our results are a factor of 1×105 (3×105) more accurate for the E2 (E3) transition compared to previous measurements. The results open up the way to search for new physics via precise isotope shift measurements and improved tests of local Lorentz invariance using the metastable F27/2 state of Yb+. © 2020 authors. Published by the American Physical Society. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI

“I'm from Europe, but I'm not European”: Television and children's identities in England and Bulgaria

This is an Accepted Manuscript of an article published by Taylor & Francis in Journal of Children and Media on 5/11/2012 available online: http://wwww.tandfonline.com/10.1080/17482798.2012.740416This article examines the role television (TV) plays in the development of primary school children's European knowledge and identities in England and Bulgaria. It compares the media coverage on Europe and the European Union with pupils' European perceptions and identities. The article reports data from 174 qualitative interviews with children and the content analysis of seven TV programmes. It concludes that TV plays a strong role in collective identities when a topic is salient on the agenda. TV raises awareness and knowledge and sets the direction of understanding. Yet, despite the higher salience of Europe on the Bulgarian media agenda, Bulgarians feel less European than English children. The article provides an explanation to this phenomenon, thus filling an important gap in the literature about the media's role in collective identities formation from an early age. It also adopts an innovative approach in the study of agenda-setting theory by investigating its application among children