6685期

最新文章

• Tandem modules get better AI翻译
  作者：Chen, Cong; Zhao, Dewei
  作者单位：Sichuan University; Sichuan University
  摘要：An all-perovskite tandem solar module breaks 24% efficiency
• Prebiotically plausible chemoselective pantetheine synthesis in water AI翻译
  作者：Fairchild, Jasper; Islam, Saidul; Singh, Jyoti; Bucar, Dejan-Kresimir; Powner, Matthew W.
  作者单位：University of London; University College London; University of London; King's College London; University of London; King's College London
  摘要：Coenzyme A (CoA) is essential to all life on Earth, and its functional subunit, pantetheine, is important in many origin-of-life scenarios, but how pantetheine emerged on the early Earth remains a mystery. Earlier attempts to selectively synthesize pantetheine failed, leading to suggestions that simpler thiols must have preceded pantetheine at the origin of life. In this work, we report high-yielding and selective prebiotic syntheses of pantetheine in water. Chemoselective multicomponent aldol...
• Emission lines due to ionizing radiation from a compact object in the remnant of Supernova 1987A AI翻译
  作者：Fransson, C.; Barlow, M. J.; Kavanagh, P. J.; Larsson, J.; Jones, O. C.; Sargent, B.; Meixner, M.; Bouchet, P.; Temim, T.; Wright, G. S.; Blommaert, J. A. D. L.; Habel, N.; Hirschauer, A. S.; Hjorth, J.; Lenkic, L.; Tikkanen, T.; Wesson, R.; Coulais, A.; Fox, O. D.; Gastaud, R.; Glasse, A.; Jaspers, J.; Krause, O.; Lau, R. M.; Nayak, O.; Rest, A.; Colina, L.; van Dishoeck, E. F.; Guedel, M.; Henning, Th.; Lagage, P. -o.; Ostlin, G.; Ray, T. P.; Vandenbussche, B.
  作者单位：Oskar Klein Centre; Stockholm University; University of London; University College London; Maynooth University; Dublin Institute for Advanced Studies; Oskar Klein Centre; Royal Institute of Technology; University of Edinburgh; Space Telescope Science Institute; Johns Hopkins University; National Aeronautics & Space Administration (NASA); NASA Jet Propulsion Laboratory (JPL); California Institute of Technology; Centre National de la Recherche Scientifique (CNRS); Universite Paris Saclay; Princeton University; Vrije Universiteit Brussel; University of Copenhagen; Niels Bohr Institute; National Aeronautics & Space Administration (NASA); NASA Ames Research Center; Universities Space Research Association (USRA); University of Leicester; Cardiff University; Universite PSL; Observatoire de Paris; Sorbonne Universite; Universite Paris Saclay; Max Planck Society; National Science Foundation (NSF); National Aeronautics & Space Administration (NASA); NASA Goddard Space Flight Center; Consejo Superior de Investigaciones Cientificas (CSIC); CSIC - Centro de Astrobiologia (INTA); Max Planck Society; Leiden University; Leiden University - Excl LUMC; University of Vienna; KU Leuven
  摘要：The nearby Supernova 1987A was accompanied by a burst of neutrino emission, which indicates that a compact object (a neutron star or black hole) was formed in the explosion. There has been no direct observation of this compact object. In this work, we observe the supernova remnant with JWST spectroscopy, finding narrow infrared emission lines of argon and sulfur. The line emission is spatially unresolved and blueshifted in velocity relative to the supernova rest frame. We interpret the lines a...
• FDA OKs frostbite treatment AI翻译
  作者：Brainard, Jeffrey
• Global and regional temperature change over the past 4.5 million years AI翻译
  作者：Clark, Peter U.; Shakun, Jeremy D.; Rosenthal, Yair; Koehler, Peter; Bartlein, Patrick J.
  作者单位：Oregon State University; Ulster University; Boston College; Rutgers University System; Rutgers University New Brunswick; Rutgers University System; Rutgers University New Brunswick; Helmholtz Association; Alfred Wegener Institute, Helmholtz Centre for Polar & Marine Research; University of Oregon
  摘要：Much of our understanding of Cenozoic climate is based on the record of delta 18O measured in benthic foraminifera. However, this measurement reflects a combined signal of global temperature and sea level, thus preventing a clear understanding of the interactions and feedbacks of the climate system in causing global temperature change. Our new reconstruction of temperature change over the past 4.5 million years includes two phases of long-term cooling, with the second phase of accelerated cool...
• Stellar remains of 1987 supernova found at last AI翻译
  作者：Clery, Daniel
• Overcoming the noise in neural computingCircuit strategies can enable noisy analog hardware to achieve high precision AI翻译
  作者：Aimone, James B.; Agarwal, Sapan
  作者单位：United States Department of Energy (DOE); Sandia National Laboratories; United States Department of Energy (DOE); Sandia National Laboratories
• Arctic sea ice retreat fuels boreal forest advance AI翻译
  作者：Dial, Roman J.; Maher, Colin T.; Hewitt, Rebecca E.; Wockenfuss, Amy M.; Wong, Russell E.; Crawford, Daniel J.; Zietlow, Madeline G.; Sullivan, Patrick F.
  作者单位：Alaska Pacific University; University of Alaska System; University of Alaska Anchorage; Northern Arizona University; United States Department of Agriculture (USDA); United States Forest Service; Amherst College; University of Alaska System; University of Alaska Anchorage
  摘要：Climate-induced northward advance of boreal forest is expected to lessen albedo, alter carbon stocks, and replace tundra, but where and when this advance will occur remains largely unknown. Using data from 19 sites across 22 degrees of longitude along the tree line of northern Alaska, we show a stronger temporal correlation of tree ring growth with open water uncovered by retreating Arctic sea ice than with air temperature. Spatially, our results suggest that tree growth, recruitment, and rang...
• Passion is not misconduct AI翻译
  作者：Thorp, H. Holden
  摘要：University of Pennsylvania climate scientist Michael Mann was awarded more than $1 million in a lawsuit against bloggers who accused him of scientific misconduct in inflammatory terms, likening his treatment of data to what a noted child molester did to children. The verdict suggests that there are limits to which scientists working on politically sensitive topics can be falsely attacked. But the case also says something profound about the difference between matters of opinion and scientific i...
• An oxidative photocyclization approach to the synthesis of Securiflustra securifrons alkaloids AI翻译
  作者：Alexander, Brandon W.; Bartfield, Noah M.; Gupta, Vaani; Mercado, Brandon Q.; Del Campo, Mark; Herzon, Seth B.
  作者单位：Yale University; Yale University; Rigaku Corporation; Yale University; Yale University
  摘要：Securines and securamines are cytotoxic alkaloids that contain reactive alkene and heterocyclic residues embedded in skeletons comprising four to six oxidized rings. This structural complexity imparts a rich chemistry to the isolates but has impeded synthetic access to the structures in the nearly three decades since their isolation. We present a flexible route to eight isolates that exemplify the three skeletal classes of metabolites. The route proceeds by the modular assembly of the advanced...