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  • 1
    Publication Date: 2009-10-06
    Description: Apatite fission-track (AFT) analyses were performed on 13 Late Palaeozoic samples in order to unravel the late- to post-Variscan evolution of the Ardennes. The dated AFT ages cover a range from 290{+/-}33 Ma to 168{+/-}12 Ma, and the mean confined track lengths correspond to a unimodal distribution, with means varying between 13.1{+/-}0.1 {micro}m and 11.7{+/-}0.3 {micro}m. These ages for the sedimentary rocks are clearly younger than the respective stratigraphic ages, indicative of a cooling through the apatite partial annealing zone after post-depositional complete annealing. All available AFT data (290-146 Ma) from this region might be classified as three groups, that is 290-229 Ma, 218-198 Ma and 190-146 Ma, at least in correlation with three exhumation events. Using an inverse model, four major cooling episodes are identified from the modelled temperature-time (T-t) paths. The first rapid cooling (4.2-5.4 {degrees}C Ma-1, 320-300 Ma) corresponds to the late-Variscan rapid thrusting that ceased at about 300 Ma. The second cooling episode (0.2-4.0 {degrees}C Ma-1, up to 230 Ma) activated differentially, and was probably controlled by the post-Variscan transtension. The third cooling regime (0.1-0.3 {degrees}C Ma-1, 230-45 Ma) in the Ardennes Allochthon is slow, and represents a long-term and slow exhumation. In the Brabant Parautochthon, however, it is subdivided into 0.7 {degrees}C Ma-1 (225-110 Ma) and 0.2 {degrees}C Ma-1 (110-45 Ma). The last accelerated cooling (0.7-1.1 {degrees}C Ma-1, since 45 Ma) that affected the whole Ardennes is associated with a south-north compression during the Pyrenean phase.
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  • 2
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    Luxembourg: Luxembourg Income Study (LIS)
    Publication Date: 2017-05-30
    Description: This paper compares poverty in the U.K. with 19 other countries. It is of particular interest because it uses the third wave of LIS data (early 1990 time period) and because it includes a number of of transitional economies as well as Taiwan. The main finding of this paper is that the overall pre-transfer poverty rate for the U.K. is the fifth highest our of the 20 countries and is relatively high for lone parents and couples with children. The result of direct taxes and social security benefits is to reduce the poverty rate but leaves the U.K. with the third highest, next only to the U.S. and Russia. In addition, poverty rates have increased more in the U.K. during the 1990's than other countries studied.
    Keywords: ddc:330 ; Armut ; Einkommensverteilung ; Großbritannien ; Industrieländer ; Osteuropa
    Repository Name: EconStor: OA server of the German National Library of Economics - Leibniz Information Centre for Economics
    Language: English
    Type: doc-type:workingPaper
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  • 3
    Publication Date: 2011-08-24
    Description: The evolutionary divergence of cnidarian and bilaterian lineages from their remote metazoan ancestor occurred at an unknown depth in time before the Cambrian, since crown group representatives of each are found in Lower Cambrian fossil assemblages. We report here a variety of putative embryonic, larval, and adult microfossils deriving from Precambrian phosphorite deposits of Southwest China, which may predate the Cambrian radiation by 25-45 million years. These are most probably of cnidarian affinity. Large numbers of fossilized early planula-like larvae were observed under the microscope in sections. Though several forms are represented, the majority display remarkable conformity, which is inconsistent with the alternative that they are artifactual mineral inclusions. Some of these fossils are preserved in such high resolution that individual cells can be discerned. We confirm in detail an earlier report of the presence in the same deposits of tabulates, an extinct crown group anthozoan form. Other sections reveal structures that most closely resemble sections of basal modern corals. A large number of fossils similar to modern hydrozoan gastrulae were also observed. These again displayed great morphological consistency. Though only a single example is available, a microscopic animal remarkably similar to a modern adult hydrozoan is also presented. Taken together, the new observations reported in this paper indicate the existence of a diverse and already differentiated cnidarian fauna, long before the Cambrian evolutionary event. It follows that at least stem group bilaterians must also have been present at this time.
    Keywords: Life Sciences (General)
    Type: Developmental biology (ISSN 0012-1606); Volume 248; 1; 182-96
    Format: text
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  • 4
    Publication Date: 2016-09-22
    Description: © The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of General Physiology 139 (2012): 19-30, doi:10.1085/jgp.201110717.
    Description: Two types of microvillar photoreceptors in the neural tube of amphioxus, an early chordate, sense light via melanopsin, the same photopigment as in “circadian” light detectors of higher vertebrates. Because in amphioxus melanopsin activates a Gq/phospholipase C cascade, like phototransduction in arthropods and mollusks, possible commonalities in the photoconductance were investigated. Unlike other microvillar photoreceptors, reversal of the photocurrent can only be attained upon replacement of extracellular Na+. In addition to Na+, Ca2+ is also permeant, as indicated by the fact that (a) in normal ionic conditions the photocurrent remains inward at Vm 〉 ENa; (b) in Na-free solution a small residual inward photocurrent persists at Vm near resting level, provided that Ca is present; and (c) Vrev exhibits a modest shift with [Ca]o manipulations. The unusual reversal is accounted for by an uncommonly low permeability of the light-dependent channels to K+, as [K]o only marginally affects the photocurrent amplitude and its reversal. Lanthanum and ruthenium red (RuR), two TRP channel antagonists, reversibly suppress the response to photostimulation of moderate intensity; therefore, the melanopsin-initiated cascade may recruit ion channels of the same family as those of rhabdomeric photoreceptors. With brighter lights, blockage declines, so that both La3+ and RuR induce a right shift in the sensitivity curve without a reduction of its asymptote. Nonetheless, an effect on the transduction cascade, rather than the channels, was ruled out on the basis of the voltage dependency of the blockade and the lack of effects of intracellular application of the same substances. The mechanisms of action of these antagonists thus entail a state-dependent blockade, with a higher affinity for the channel in the closed conformation. Collectively, the results indicate a kinship of the light-sensitive channels of amphioxus with those of invertebrate rhabdomeric visual cells and support the representation of this lineage of photoreceptors among chordates.
    Description: This work was supported by National Science Foundation grant 0918930.
    Description: 2012-06-26
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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  • 5
    Publication Date: 2019-07-12
    Description: Disclosed are a method and system for video compression, wherein the video encoder has low computational complexity and high compression efficiency. The disclosed system comprises a video encoder and a video decoder, wherein the method for encoding includes the steps of converting a source frame into a space-frequency representation; estimating conditional statistics of at least one vector of space-frequency coefficients; estimating encoding rates based on the said conditional statistics; and applying Slepian-Wolf codes with the said computed encoding rates. The preferred method for decoding includes the steps of; generating a side-information vector of frequency coefficients based on previously decoded source data, encoder statistics, and previous reconstructions of the source frequency vector; and performing Slepian-Wolf decoding of at least one source frequency vector based on the generated side-information, the Slepian-Wolf code bits and the encoder statistics.
    Keywords: Instrumentation and Photography
    Format: application/pdf
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  • 6
    Publication Date: 2019-07-10
    Description: The Pb-2.2 wt pct Sb alloy has been directionally solidified in 1-, 2-, 3-, and 7-mm-diameter crucibles with planar and dendritic liquid-solid interface orphology. For plane front solidification, the experimentally observed macrosegregation along the solidified length follows the relationship proposed by Favier. Application of a 0.4 T transverse magnetic field has no effect on the extent of convection. Reducing the ampoule diameter appears to decrease the extent of convection. However, extensive convection is still present even in the 1-mm-diameter crucible. An extrapolation of the observed behavior indicated that nearly diffusive transport conditions require ampoules that are about 40 microns in diameter. Reduction of the crucible diameter does not appear to have any significant effect on the primary dendrite spacing. However, it results in considerable distortion of the dendrite morphology and ordering. This is especially true for the 1-mm diameter samples.
    Keywords: Metals and Metallic Materials
    Type: E-14334
    Format: text
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  • 7
    Publication Date: 2019-08-28
    Description: An engineered structure is proposed that can alleviate quasi-particle recombination losses via the existence of a phononic band gap that overlaps the 2-Delta energy of phonons produced during recombination of quasi-particles. Attention is given to a 1D Kronig-Penny model for phonons normally incident to the layers of a multilayered superconducting tunnel junction as an idealized example. A device with a high density of Bragg resonances is identified as desirable; both Nb/Si and NbN/SiN superlattices have been produced, with the latter having generally superior performance.
    Keywords: SOLID-STATE PHYSICS
    Type: In: EUV, X-ray, and gamma-ray instrumentation for astronomy III; Proceedings of the Meeting, San Diego, CA, July 22-24, 1992 (A93-29476 10-35); p. 12-23.
    Format: text
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  • 8
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    In:  Other Sources
    Publication Date: 2019-08-27
    Description: We use time-resolved charge-coupled device (CCD) images to assess the frequency of splitting of comets. When blinked on a computer, the CCD images provide relatively high and uniform sensitivity to comoving companions. We find that 3 comets are split in a sample of 49, and estimate that the cometary splitting rate is S approximately 0.01 per year per comet or larger. This large rate suggests that splitting may be an important destructive process for the cometary nuclei.
    Keywords: ASTRONOMY
    Type: ICARUS (ISSN 0019-1035); 108; 2, pt; p. 265-271
    Format: text
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  • 9
    Publication Date: 2013-10-16
    Type: http://purl.org/eprint/type/Book
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  • 10
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    In:  VI Hotine-Marussi Symposium on Theoretical and Computational Geodesy ; Year: 2008 ; Pages: 138-142
    Publication Date: 2013-10-16
    Type: http://purl.org/eprint/type/BookItem
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