GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Deflagration of white dwarfs as a model for type-I supernovae (1985)
    Springer
    Astrophysics and space science 109 (1985), S. 277-285 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Carbon-oxygen white dwarfs may be the progenitors of type-I supernovae. Spherically-symmetric models of such dwarfs have been evolved from an artificial core incineration. The convectively unstable incinerated region was allowed to grow at a velocity prescribed by the mixing-length theory of convection. The mixing length can be varied to give different cases. In all the cases considered the dwarfs exploded and were totally disrupted. The calculations were stopped after the dwarf matter had gone into homologous expansion. The model with the best estimated mixing length incinerated 0.8M ⊙. The energy released in burning this amount of carbon-oxygen to56Ni provides a disrupted dwarf with velocities suitable for type-I supernovae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00651274
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    One-photon and two-photon annihilation of positronium in strong magnetic fields (1978)
    Springer
    Astrophysics and space science 58 (1978), S. 83-88 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In the presence of a strong magnetic field (such as those believed to be characteristic of neutron stars:B≳-1012 Gauss) positronium may annihilate through the emission of a single photon, the magnetic field providing the photon momentum. We report on calculations of the one-photon and two-photon annihilation rates for the ground state of positronium, for magnetic fields in the range (1–44)×1012 Gauss, and give, in the two-photon case, the minimum energy half-width of the emission line due to the momentum contributions from the magnetic field. We find that unless neutron stars have magnetic fields in excess of 1013 Gauss, it is unlikely that the one-photon process will be observable.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00645375
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Neutrino scattering by phonons in neutron star matter (1978)
    Springer
    Astrophysics and space science 57 (1978), S. 409-417 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Neutrinos couple through a weak neutral current to the density of matter, in particular to the neutron density. Density fluctuations, or phonons, in the neutron fluid may be emitted or absorbed by neutrinos passing through the matter. At high densities, temperatures and neutrino energies the neutrino mean free paths for phonon emission and absorption can be ≤106 cm. Significant changes in the neutrino momentum and energy accompany these processes. We present a model calculation for neutrino scattering by phonons, and representative numerical results for the neutrino mean free path and mean energy and momentum changes fork B T andE v both ranging from 1 to 27 MeV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00639333
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Neutrino-pair bremsstrahlung in collisions between neutrons and nuclei in neutron star matter (1977)
    Springer
    Astrophysics and space science 48 (1977), S. 159-164 
    Details
    ISSN: 1572-946X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract In neutron star matter over the density range 4.3×1011〈-ϱ≤4×1014 g cm−3 there are both free neutrons and neutron-rich nuclei. If there is a weak neutral current interaction between neutrinos and neutrons, as suggested by recent experiments, then when neutrons scatter off nuclei they may emit $$v\bar v$$ pairs as bremsstrahlung radiation. We calculate the associated emissivity for degenerate (but not superfluid) neutrons and uncorrelated (not crystallized) nuclei. We find that, under these conditions. this emissivity can under some conditions compare with that calculated by Festa and Ruderman for $$v\bar v$$ bremsstrahlung in electron-nucleus collisions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00643047
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Can Pulsar Masses be Determined ? (1970)
    [s.l.] : Nature Publishing Group
    Nature 225 (1970), S. 353-354 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] To determine the mass it is necessary to observe the immediate shifts DW, DW and DW in the angular frequency (and its first two time derivatives) caused by the starquake. From these observations one can form the dimensionless parameter Q = (An)2/AQAii (1) In the two component model Q is given by ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/225353a0
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    facet.materialart.
    Unknown
    On the Geology of Natal (South Africa): being a paper read before the Natural History Association of Natal on the 27th June, 1868 (1868)
    Adams
    In:  Adams, Durban, South Africa, 23 pp.
    Details
    Publication Date: 2022-01-26
    Type: Book , NonPeerReviewed
    Format: text
    DOI: 10.3931/e-rara-82027
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Book
  • 7
    facet.materialart.
    Unknown
    Summertime increases in upper-ocean stratification and mixed-layer depth (2021)
    Nature Research
    Details
    Publication Date: 2024-02-07
    Description: The surface mixed layer of the world ocean regulates global climate by controlling heat and carbon exchange between the atmosphere and the oceanic interior1,2,3. The mixed layer also shapes marine ecosystems by hosting most of the ocean’s primary production4 and providing the conduit for oxygenation of deep oceanic layers. Despite these important climatic and life-supporting roles, possible changes in the mixed layer during an era of global climate change remain uncertain. Here we use oceanographic observations to show that from 1970 to 2018 the density contrast across the base of the mixed layer increased and that the mixed layer itself became deeper. Using a physically based definition of upper-ocean stability that follows different dynamical regimes across the global ocean, we find that the summertime density contrast increased by 8.9 ± 2.7 per cent per decade (10−6–10−5 per second squared per decade, depending on region), more than six times greater than previous estimates. Whereas prior work has suggested that a thinner mixed layer should accompany a more stratified upper ocean5,6,7, we find instead that the summertime mixed layer deepened by 2.9 ± 0.5 per cent per decade, or several metres per decade (typically 5–10 metres per decade, depending on region). A detailed mechanistic interpretation is challenging, but the concurrent stratification and deepening of the mixed layer are related to an increase in stability associated with surface warming and high-latitude surface freshening8,9, accompanied by a wind-driven intensification of upper-ocean turbulence10,11. Our findings are based on a complex dataset with incomplete coverage of a vast area. Although our results are robust within a wide range of sensitivity analyses, important uncertainties remain, such as those related to sparse coverage in the early years of the 1970–2018 period. Nonetheless, our work calls for reconsideration of the drivers of ongoing shifts in marine primary production, and reveals stark changes in the world’s upper ocean over the past five decades.
    Type: Article , PeerReviewed
    Format: text
    Format: text
    Format: text
    Format: text
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    OceanRep: Article in a Scientific Journal - peer-reviewed
  • 8
    facet.materialart.
    Unknown
    Cargo engagement protects protease adaptors from degradation in a substrate-specific manner [Microbiology] (2017)
    The American Society for Biochemistry and Molecular Biology (ASBMB)
    Details
    Publication Date: 2017-07-01
    Description: Protein degradation in bacteria is a highly controlled process involving proteolytic adaptors that regulate protein degradation during cell cycle progression or during stress responses. Many adaptors work as scaffolds that selectively bind cargo and tether substrates to their cognate proteases to promote substrate destruction, whereas others primarily activate the target protease. Because adaptors must bind their cognate protease, all adaptors run the risk of being recognized by the protease as substrates themselves, a process that could limit their effectiveness. Here we use purified proteins in a reconstituted system and in vivo studies to show that adaptors of the ClpXP protease are readily degraded but that cargo binding inhibits this degradation. We found that this principle extends across several adaptor systems, including the hierarchical adaptors that drive the Caulobacter bacterial cell cycle and the quality control adaptor SspB. We also found that the ability of a cargo to protect its adaptor is adaptor substrate-specific, as adaptors with artificial degradation tags were not protected even though cargo binding is unaffected. Our work points to an optimization of inherent adaptor degradation and cargo binding that ensures that robust adaptor activity is maintained when high amounts of substrate must be delivered and that adaptors can be eliminated when their tasks have been completed.
    Print ISSN: 0021-9258
    Electronic ISSN: 1083-351X
    Topics: Biology , Chemistry and Pharmacology
    Published by The American Society for Biochemistry and Molecular Biology (ASBMB)
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    Evidence of Early Metalworking in Arctic Canada (2014)
    Wiley-Blackwell
    Details
    Publication Date: 2014-12-02
    Description: This paper examines new evidence related to an early (pre-Columbian) European presence in Arctic Canada. Artifacts from archaeological sites that had been assumed to relate to pre-Inuit indigenous occupations of the region in the centuries around A.D. 1000 have recently been recognized as having been manufactured using European technologies. We report here on the SEM-EDS analysis of a small stone vessel recovered from a site on Baffin Island. The interior of the vessel contains abundant traces of copper–tin alloy (bronze) as well as glass spherules similar to those associated with high-temperature processes. These results indicate that it had been used as a crucible. This artifact may represent the earliest evidence of high-temperature nonferrous metalworking in the New World north of Mesoamerica.
    Print ISSN: 0883-6353
    Electronic ISSN: 1520-6548
    Topics: Archaeology , Geosciences
    Published by Wiley-Blackwell
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Overview of the Arctic Sea state and boundary layer physics program (2019)
    American Geophysical Union
    Details
    Publication Date: 2022-05-25
    Description: Author Posting. © American Geophysical Union, 2018. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research-Oceans 123(12), (2018): 8674-8687, doi:10.1002/2018JC013766.
    Description: A large collaborative program has studied the coupled air‐ice‐ocean‐wave processes occurring in the Arctic during the autumn ice advance. The program included a field campaign in the western Arctic during the autumn of 2015, with in situ data collection and both aerial and satellite remote sensing. Many of the analyses have focused on using and improving forecast models. Summarizing and synthesizing the results from a series of separate papers, the overall view is of an Arctic shifting to a more seasonal system. The dramatic increase in open water extent and duration in the autumn means that large surface waves and significant surface heat fluxes are now common. When refreezing finally does occur, it is a highly variable process in space and time. Wind and wave events drive episodic advances and retreats of the ice edge, with associated variations in sea ice formation types (e.g., pancakes, nilas). This variability becomes imprinted on the winter ice cover, which in turn affects the melt season the following year.
    Description: This program was supported by the Office of Naval Research, Code 32, under Program Managers Scott Harper and Martin Jeffries. The crew of R/V Sikuliaq provide outstanding support in collecting the field data, and the US National Ice Center, German Aerospace Center (DLR), and European Space Agency facilitated the remote sensing collections and daily analysis products. RADARSAT‐2 Data and Products are from MacDonald, Dettwiler, and Associates Ltd., courtesy of the U.S. National Ice Center. Data, supporting information, and a cruise report can be found at http://www.apl.uw.edu/arcticseastate
    Keywords: Arctic ; waves ; autumn ; sea ice ; Beaufort ; flux
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    PAPER (OA)
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...