ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
Collection
  • 1
    Publication Date: 2011-08-09
    Description: Stream particles are nanometer-scale dust particles ejected with speeds $\gtrsim$100 km s−1 from both the Jovian and Saturnian systems. Here we report the dynamical analysis of Saturnian stream particles on the basis of observations made by the Cosmic Dust Analyzer on board the Cassini spacecraft during its first three orbits around Saturn. The time span of the presented measurements covers from the beginning of orbit A to the end of orbit C (from the Saturn orbit insertion on 1 July 2004 UTC to 16 January 2005 UTC). During these orbits the Cassini spacecraft was usually located outside but not far from Saturn's magnetosphere. The Cassini observations therefore provide important information on the dynamics of stream particles just ejected from the system. As with earlier observations, two impact populations are identified. These appear as faint but continuous impacts as well as semiregular and energetic impact bursts. Faint impacts from directions close to the Saturn line of sight are recognized as recently ejected stream particles, while energetic dust bursts most probably consist of previously ejected particles that experienced significant acceleration within the solar wind. The presented measurements not only confirm the previous proposed stream particle ejection scenario but also serve as essential inputs for detailed dynamical modeling.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2011-09-16
    Description: We analyze the dynamics and composition of Saturnian stream particles measured by the Cosmic Dust Analyser (CDA) onboard the Cassini spacecraft. To reconstruct the dynamical properties of Saturnian stream particles, we adopt a backward tracing method with in situ solar wind measurements to filter out the influence of the interplanetary magnetic field. Our results show that stream particles from Saturn have sizes ranging from 2 to 8 nm (radius) with ejection velocities between 50 and 200 kms−1. Moreover, the derived “ejection region” of stream particles in the outer part of Saturn's E ring is indicative of the dust charging condition profile in the planet's magnetosphere. By using the Cassini magnetospheric plasma measurements as input, our ejection model considers stochastic charging and well reproduces the dynamical properties of stream particles derived from backward simulations. An updated analysis of CDA stream-particle mass spectra confirms that the silicateous material is the most probable composition of Saturnian stream particles, in contrast to E ring particles whose composition is dominated by water ice. This compositional discrepancy can be reproduced by our model if the different sputter efficiencies of silicateous material and water ice are considered. We suggest that silicateous impurities released from icy grains at the outer E ring are the most probable source of Saturnian stream particles. Finally, we discuss the role of dust particles as a mobile neutral reservoir in Saturn's magnetosphere which may be responsible for certain features in the Cassini O and O2+ measurements.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    facet.materialart.
    Unknown
    In:  Eos, Trans., Am. Geophys. Un., London, Army Corps of Engineers, Woodward-Clyde Consultants, vol. 80, no. 48, pp. 575, 579, 581, pp. 1062, (ISBN: 0-12-018847-3)
    Publication Date: 1999
    Keywords: Project report/description ; Volcanology ; Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Global Positioning System ; Gravimetry, Gravitation ; Geochemistry ; microgravity ; changes ; no ; deformation ; gas ; sulfur
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 2016-07-27
    Description: A flow system to perform Chan–Lam coupling reactions of various amines and arylboronic acids has been realised employing molecular oxygen as an oxidant for the re-oxidation of the copper catalyst enabling a catalytic process. A tube-in-tube gas reactor has been used to simplify the delivery of the oxygen accelerating the optimisation phase and allowing easy access to elevated pressures. A small exemplification library of heteroaromatic products has been prepared and the process has been shown to be robust over extended reaction times. Beilstein J. Org. Chem. 2016, 12, 1598–1607. doi:10.3762/bjoc.12.156
    Keywords: Chan–Lam couplingflow chemistrygases in flowoxygen“tube-in-tube”
    Electronic ISSN: 1860-5397
    Topics: Chemistry and Pharmacology
    Published by Beilstein-Institut
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Publication Date: 2015-04-09
    Description: The dynamics of the 2–12 January 2010 effusive eruption at Piton de la Fournaise volcano were examined through seismic and infrasound records, time-lapse photography, SO 2 flux measurements, deformation data and direct observations. Digital elevation models were constructed for four periods of the eruption, thus providing an assessment of the temporal evolution of the morphology, the volume and the extrusion rate of the lava flow. These data were compared to the continuous recording of the seismic and infrasonic waves, and a linear relationship was found between the seismic energy of the tremor and the lava extrusion rate. This relationship is supported by data from three other summit eruptions of Piton de la Fournaise and gives total volume and average lava extrusion rate in good agreement with previous studies. We can therefore provide an estimate of the lava extrusion rate for the January 2010 eruption with a very high temporal resolution. We found an average lava extrusion rate of 2.4 m 3 S −1 with a peak of 106.6 m 3 S −1 during the initial lava fountaining phase. We use the inferred average lava extrusion rate during the lava fountaining phase (30.2 m 3 S −1 ) to estimate the value of the initial overpressure in the magma reservoir, which we found to range from 3.7×10 6 Pa to 5.9×10 6 Pa. Finally, based on the estimated initial overpressure, the volume of magma expelled during the lava fountaining phase and geodetic data, we inferred the volume of the magma reservoir using a simple Mogi model, between 0.25km 3 and 0.54km 3 , which is in good agreement with previous studies.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Publication Date: 2011-09-09
    Description: Author(s): Zlatko Dimcovic, Daniel Rockwell, Ian Milligan, Robert M. Burton, Thinh Nguyen, and Yevgeniy Kovchegov We formulate a framework for discrete-time quantum walks, motivated by classical random walks with memory. We present a specific representation of the classical walk with memory 2, on which this is based. The framework has no need for coin spaces, it imposes no constraints on the evolution operator ... [Phys. Rev. A 84, 032311] Published Thu Sep 08, 2011
    Keywords: Quantum information
    Print ISSN: 1050-2947
    Electronic ISSN: 1094-1622
    Topics: Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2014-09-13
    Description: A bstract Paleontologists have long speculated that the bizarre, giant Ordovician gastropods Maclurites Le Sueur, 1818 and Maclurina Ulrich and Scofield, 1897 lived more like suspension-feeding oysters than typical algivorous snails. Geometric and eigenshape morphometrics demonstrate the plausibility of this lifestyle, but with a twist. The apertures of these gastropods were small ellipsoids when young, transitioning rapidly to polygonal morphologies at maturity, with angulations (sinuses) occurring in regions associated with development of mature ctenidia (gills) and enhanced stability on the seafloor. Combined with knowledge of extant suspension-feeding gastropods and functional and phylogenetic analysis of the anatomy of other fossil relatives, this ontogenetic pattern suggests these snails began life as typical mobile algae-grazers, but switched to sedentary suspension-feeders as they aged.
    Print ISSN: 0022-3360
    Electronic ISSN: 1937-2337
    Topics: Geosciences
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2014-11-22
    Description: Many bacteria take up DNA from their environment as part of the process of natural transformation. DNA uptake allows microorganisms to gain genetic diversity and can lead to the spread of antibiotic resistance or virulence genes within a microbial population. Development of genetic competence (Com) in Bacillus subtilis is a highly regulated process that culminates in expression of several late competence genes and formation of the DNA uptake apparatus. The late competence operon comF encodes a small protein of unknown function, ComFB. To gain insight into the function of ComFB, we determined its three-dimensional structure via X-ray crystallography. ComFB is a dimer, and each subunit consists of four α-helices connected by short loops and one extended β-strand-like stretch. Each subunit contains one zinc-binding site formed by four cysteines, which are unusually spaced in the primary sequence. Using structure- and bioinformatics-guided substitutions we analyzed the intersubunit interface of the ComFB dimer. Based on these analyses, we conclude that ComFB is an obligate dimer. We also characterized ComFB in vivo and found that this protein is produced in competent cells and is localized to the cytosol. Consistent with previous reports, we showed that deletion of ComFB does not affect DNA uptake function. Combining our results, we conclude that ComFB is unlikely to be a part of the DNA uptake machinery under tested conditions and instead may have a regulatory function.
    Print ISSN: 0144-8463
    Electronic ISSN: 1573-4935
    Topics: Biology , Chemistry and Pharmacology
    Published by Portland Press
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2008-08-12
    Description: The domestication of cattle, sheep and goats had already taken place in the Near East by the eighth millennium bc. Although there would have been considerable economic and nutritional gains from using these animals for their milk and other products from living animals-that is, traction and wool-the first clear evidence for these appears much later, from the late fifth and fourth millennia bc. Hence, the timing and region in which milking was first practised remain unknown. Organic residues preserved in archaeological pottery have provided direct evidence for the use of milk in the fourth millennium in Britain, and in the sixth millennium in eastern Europe, based on the delta(13)C values of the major fatty acids of milk fat. Here we apply this approach to more than 2,200 pottery vessels from sites in the Near East and southeastern Europe dating from the fifth to the seventh millennia bc. We show that milk was in use by the seventh millennium; this is the earliest direct evidence to date. Milking was particularly important in northwestern Anatolia, pointing to regional differences linked with conditions more favourable to cattle compared to other regions, where sheep and goats were relatively common and milk use less important. The latter is supported by correlations between the fat type and animal bone evidence.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Evershed, Richard P -- Payne, Sebastian -- Sherratt, Andrew G -- Copley, Mark S -- Coolidge, Jennifer -- Urem-Kotsu, Duska -- Kotsakis, Kostas -- Ozdogan, Mehmet -- Ozdogan, Asly E -- Nieuwenhuyse, Olivier -- Akkermans, Peter M M G -- Bailey, Douglass -- Andeescu, Radian-Romus -- Campbell, Stuart -- Farid, Shahina -- Hodder, Ian -- Yalman, Nurcan -- Ozbasaran, Mihriban -- Bicakci, Erhan -- Garfinkel, Yossef -- Levy, Thomas -- Burton, Margie M -- England -- Nature. 2008 Sep 25;455(7212):528-31. doi: 10.1038/nature07180. Epub 2008 Aug 6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Organic Geochemistry Unit, Bristol Biogeochemistry Research Centre, School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK. r.p.evershed@bristol.ac.uk〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/18690215" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Cattle/*physiology ; Ceramics/analysis ; Dairying/*history ; Europe ; Europe, Eastern ; Fatty Acids/analysis ; Goats ; History, Ancient ; Humans ; Meat ; Milk/chemistry/*history/*utilization ; Sheep
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2007-07-14
    Description: Strombolian-type eruptive activity, common at many volcanoes, consists of regular explosions driven by the bursting of gas slugs that rise faster than surrounding magma. Explosion quakes associated with this activity are usually localized at shallow depth; however, where and how slugs actually form remain poorly constrained. We used spectroscopic measurements performed during both quiescent degassing and explosions on Stromboli volcano (Italy) to demonstrate that gas slugs originate from as deep as the volcano-crust interface (approximately 3 kilometers), where both structural discontinuities and differential bubble-rise speed can promote slug coalescence. The observed decoupling between deep slug genesis and shallow (approximately 250-meter) explosion quakes may be a common feature of strombolian activity, determined by the geometry of plumbing systems.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Burton, Mike -- Allard, Patrick -- Mure, Filippo -- La Spina, Alessandro -- New York, N.Y. -- Science. 2007 Jul 13;317(5835):227-30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Istituto Nazionale di Geofisica e Vulcanologia, Catania, Italy. burton@ct.ingv.it〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/17626881" 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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...