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  • American Association for the Advancement of Science (AAAS)  (14)
  • Nature Publishing Group  (5)
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  • 1
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 219 (1968), S. 1292-1292 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] SIR,-Two months have passed since you published the last of a series of very provoking articles drawing attention to the many weaknesses in university government, and we have waited patiently and expectantly for some sort of reaction from your readers. Not one word in reply has yet been published. ...
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The lakes were found in field surveys in the summers of 1982 and 1983. We used motorized rubber boats to make bathymie maps with a recording sonar, to sample for plankton, water chemistry, 14C productivity, thermal stratification and light penetration and to raise sediment cores with a Livingstone ...
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  • 3
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 195 (1962), S. 1220-1221 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Gemmae are irradiated with X-rays and grown on a solid (agar) defined medium3 at 17 -22 C. A thallus arises presumably from a single apical cell at each of the two notches, at opposite ends of a gemma. Thalli are observed at the end of the second week and scored either as normal (35 units long, ...
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 204 (1964), S. 596-597 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The gemmae of Marchantia polymorpha, a bryophyte, are convenient well-defined organs with features which make it possible to examine the radiosensitivity of particular cells within the structure. Normally, one of the two apical cells at each end of the gemma produces the new thallus; but in the ...
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 202 (1964), S. 716-716 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Sordaria fimicola, a homothallic pyrenomycete, was grown at 28 C in Petri plates containing Difco 'Corn Meal Agar' and 0-1 per cent yeast extract. Some plates also contained specific amounts of radio-protective chemicals, and all media were adjusted to pH 5-8 with 1 N sodium hydroxide. Mycelial ...
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  • 6
    Publication Date: 2018-03-29
    Description: The Earth-Moon system likely formed as a result of a collision between two large planetary objects. Debate about their relative masses, the impact energy involved, and the extent of isotopic homogenization continues. We present the results of a high-precision oxygen isotope study of an extensive suite of lunar and terrestrial samples. We demonstrate that lunar rocks and terrestrial basalts show a 3 to 4 ppm (parts per million), statistically resolvable, difference in 17 O. Taking aubrite meteorites as a candidate impactor material, we show that the giant impact scenario involved nearly complete mixing between the target and impactor. Alternatively, the degree of similarity between the 17 O values of the impactor and the proto-Earth must have been significantly closer than that between Earth and aubrites. If the Earth-Moon system evolved from an initially highly vaporized and isotopically homogenized state, as indicated by recent dynamical models, then the terrestrial basalt-lunar oxygen isotope difference detected by our study may be a reflection of post–giant impact additions to Earth. On the basis of this assumption, our data indicate that post–giant impact additions to Earth could have contributed between 5 and 30% of Earth’s water, depending on global water estimates. Consequently, our data indicate that the bulk of Earth’s water was accreted before the giant impact and not later, as often proposed.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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  • 7
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    American Association for the Advancement of Science (AAAS)
    In: Science
    Publication Date: 2018-08-17
    Description: We document rapid and abrupt clearings of large portions of the subtropical marine low cloud deck that have implications for the global radiation balance and climate sensitivity. Over the southeast Atlantic, large areas of stratocumulus are quickly eroded, yielding partial or complete clearing along sharp transitions hundreds to thousands of kilometers in length that move westward at 8 to 12 meters per second and travel as far as 1000+ kilometers from the African coast. The westward-moving cloudiness reductions have an annual peak in occurrence in the period from April through June. The cloud erosion boundaries reduce cloud at 10-kilometer scale in less than 15 minutes, move approximately perpendicular to the mean flow, and are often accompanied by small-scale wave features. Observations suggest that the cloud erosion is caused by atmospheric gravity waves.
    Keywords: Geochemistry, Geophysics
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Geosciences , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
    Publication Date: 2015-02-24
    Description: The evolution of galaxies is connected to the growth of supermassive black holes in their centers. During the quasar phase, a huge luminosity is released as matter falls onto the black hole, and radiation-driven winds can transfer most of this energy back to the host galaxy. Over five different epochs, we detected the signatures of a nearly spherical stream of highly ionized gas in the broadband x-ray spectra of the luminous quasar PDS 456. This persistent wind is expelled at relativistic speeds from the inner accretion disk, and its wide aperture suggests an effective coupling with the ambient gas. The outflow's kinetic power larger than 10(46) ergs per second is enough to provide the feedback required by models of black hole and host galaxy coevolution.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Nardini, E -- Reeves, J N -- Gofford, J -- Harrison, F A -- Risaliti, G -- Braito, V -- Costa, M T -- Matzeu, G A -- Walton, D J -- Behar, E -- Boggs, S E -- Christensen, F E -- Craig, W W -- Hailey, C J -- Matt, G -- Miller, J M -- O'Brien, P T -- Stern, D -- Turner, T J -- Ward, M J -- New York, N.Y. -- Science. 2015 Feb 20;347(6224):860-3. doi: 10.1126/science.1259202.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Astrophysics Group, School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire ST5 5BG, UK. e.nardini@keele.ac.uk. ; Astrophysics Group, School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire ST5 5BG, UK. Center for Space Science and Technology, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA. ; Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA. ; Istituto Nazionale di Astrofisica, Osservatorio Astrofisico di Arcetri, Largo Enrico Fermi 5, I-50125 Firenze, Italy. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA. ; INAF, Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807 Merate (LC), Italy. ; Astrophysics Group, School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire ST5 5BG, UK. ; Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Pasadena, CA 91125, USA. Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA. ; Department of Physics, Technion, Haifa 32000, Israel. ; Space Science Laboratory, University of California, Berkeley, CA 94720, USA. ; Danmarks Tekniske Universitet Space-National Space Institute, Technical University of Denmark, Elektrovej 327, 2800 Lyngby, Denmark. ; Lawrence Livermore National Laboratory, Livermore, CA 94550, USA. ; Columbia Astrophysics Laboratory, Columbia University, New York, NY 10027, USA. ; Dipartimento di Matematica e Fisica, Universita degli Studi Roma Tre, Via della Vasca Navale 84, I-00146 Roma, Italy. ; Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA. ; Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK. ; Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA. ; Physics Department, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA. Eureka Scientific Inc., 2452 Delmer Street Suite 100, Oakland, CA 94602, USA. ; Department of Physics, University of Durham, South Road, Durham DH1 3LE, UK.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/25700515" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 9
    Publication Date: 2015-11-28
    Description: Solar photoconversion in semiconductors is driven by charge separation at the interface of the semiconductor and contacting layers. Here we demonstrate that time-resolved photoinduced reflectance from a semiconductor captures interfacial carrier dynamics. We applied this transient photoreflectance method to study charge transfer at p-type gallium-indium phosphide (p-GaInP2) interfaces critically important to solar-driven water splitting. We monitored the formation and decay of transient electric fields that form upon photoexcitation within bare p-GaInP2, p-GaInP2/platinum (Pt), and p-GaInP2/amorphous titania (TiO2) interfaces. The data show that a field at both the p-GaInP2/Pt and p-GaInP2/TiO2 interfaces drives charge separation. Additionally, the charge recombination rate at the p-GaInP2/TiO2 interface is greatly reduced owing to its p-n nature, compared with the Schottky nature of the p-GaInP2/Pt interface.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Yang, Ye -- Gu, Jing -- Young, James L -- Miller, Elisa M -- Turner, John A -- Neale, Nathan R -- Beard, Matthew C -- New York, N.Y. -- Science. 2015 Nov 27;350(6264):1061-5. doi: 10.1126/science.aad3459.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, CO, 80401, USA. ye.yang@nrel.gov matt.beard@nrel.gov. ; National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, CO, 80401, USA. ; National Renewable Energy Laboratory, Chemistry and Nanoscience Center, Golden, CO, 80401, USA. Material Science and Engineering Program, University of Colorado, Boulder, CO, 80309, USA.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/26612947" target="_blank"〉PubMed〈/a〉
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 10
    Publication Date: 2018-07-12
    Description: The contemporary Arctic carbon balance is uncertain, and the potential for a permafrost carbon feedback of anywhere from 50 to 200 petagrams of carbon (Schuur et al ., 2015) compromises accurate 21st-century global climate system projections. The 42-year record of atmospheric CO 2 measurements at Barrow, Alaska (71.29 N, 156.79 W), reveals significant trends in regional land-surface CO 2 anomalies (CO 2 ), indicating long-term changes in seasonal carbon uptake and respiration. Using a carbon balance model constrained by CO 2 , we find a 13.4% decrease in mean carbon residence time (50% confidence range = 9.2 to 17.6%) in North Slope tundra ecosystems during the past four decades, suggesting a transition toward a boreal carbon cycling regime. Temperature dependencies of respiration and carbon uptake suggest that increases in cold season Arctic labile carbon release will likely continue to exceed increases in net growing season carbon uptake under continued warming trends.
    Electronic ISSN: 2375-2548
    Topics: Natural Sciences in General
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