The possibility that a pairing boson might act as the 'glue' to bind electrons into a Cooper pair in superconductors with a high critical temperature (T(c)) is being actively pursued in condensed-matter physics. Gweon et al. claim that there is a large and unusual oxygen-isotope effect on the electronic structure, indicating that phonons have a special importance in high-temperature superconductors. However, we are unable to detect this unusual oxygen-isotope effect in new data collected under almost identical material and experimental conditions. Our findings point towards a more conventional influence of phonons in these materials.
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http://dx.doi.org/10.1038/nature05738 | DOI Listing |
J Am Chem Soc
October 2024
Department of Chemistry, Collaborative Innovation Center of Chemistry for Energy Materials, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Fudan University, Shanghai 200438, China.
Quantum mechanical tunneling (QMT) has long been recognized as crucial for understanding chemical reaction mechanisms, particularly in reactions involving light atoms like hydrogen. However, recent findings have expanded this understanding to include heavy-atom tunneling reactions. In this report, we present the observation of two heavy-atom tunneling reactions involving the spontaneous conversions from end-on bonded beryllium ozonide complexes, OBeOOO () and BeOBeOOO (), to their corresponding side-on bonded ozonide isomers, OBe(η-O) () and BeOBe(η-O) (), respectively, in a cryogenic neon matrix.
View Article and Find Full Text PDFSci Adv
March 2024
Department of Archaeology and History, University of Exeter, Exeter, UK.
Nature
April 2024
National Science Foundation Research Experience for Undergraduates Program, Department of Anthropology, The University of Texas, Austin, TX, USA.
Although modern humans left Africa multiple times over 100,000 years ago, those broadly ancestral to non-Africans dispersed less than 100,000 years ago. Most models hold that these events occurred through green corridors created during humid periods because arid intervals constrained population movements. Here we report an archaeological site-Shinfa-Metema 1, in the lowlands of northwest Ethiopia, with Youngest Toba Tuff cryptotephra dated to around 74,000 years ago-that provides early and rare evidence of intensive riverine-based foraging aided by the likely adoption of the bow and arrow.
View Article and Find Full Text PDFFEMS Microbiol Lett
January 2024
Center for the Pan-third Pole Environment, Lanzhou University, Lanzhou 730000, China.
Methane-oxidizing bacteria (methanotrophs) play an important role in mitigating methane emissions in various ecological environments, including cold regions. However, the response of methanotrophs in these cold environments to extreme temperatures above the in-situ temperature has not been thoroughly explored. Therefore, this study collected soil samples from Longxiazailongba (LXZ) and Qiangyong (QY) glacier forelands and incubated them with 13CH4 at 35°C under different soil water conditions.
View Article and Find Full Text PDFSci Rep
January 2024
Martin Fleischmann Memorial Project, Worthing, UK.
This paper reports the discovery that water can trigger a peculiar nuclear reaction and produce energy. Cavitation may induce unusual reactions through implosion of water vapor bubbles. Many of this research has been published formally or informally.
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