213 research outputs found
Reconstruction Mechanism of FCC Transition-Metal (001) Surfaces
The reconstruction mechanism of (001) fcc transition metal surfaces is
investigated using a full-potential all-electron electronic structure method
within density-functional theory. Total-energy supercell calculations confirm
the experimental finding that a close-packed quasi-hexagonal overlayer
reconstruction is possible for the late 5-metals Ir, Pt, and Au, while it is
disfavoured in the isovalent 4 metals (Rh, Pd, Ag). The reconstructive
behaviour is driven by the tensile surface stress of the unreconstructed
surfaces; the stress is significantly larger in the 5 metals than in 4
ones, and only in the former case it overcomes the substrate resistance to the
required geometric rearrangement. It is shown that the surface stress for these
systems is due to charge depletion from the surface layer, and that the
cause of the 4th-to-5th row stress difference is the importance of relativistic
effects in the 5 series.Comment: RevTeX 3.0, 12 pages, 1 PostScript figure available upon request] 23
May 199
Evaluation of methods for the concentration and extraction of viruses from sewage in the context of metagenomic sequencing
Viral sewage metagenomics is a novel field of study used for surveillance, epidemiological studies, and evaluation of waste water treatment efficiency. In raw sewage human waste is mixed with household, industrial and drainage water, and virus particles are, therefore, only found in low concentrations. This necessitates a step of sample concentration to allow for sensitive virus detection. Additionally, viruses harbor a large diversity of both surface and genome structures, which makes universal viral genomic extraction difficult. Current studies have tackled these challenges in many different ways employing a wide range of viral concentration and extraction procedures. However, there is limited knowledge of the efficacy and inherent biases associated with these methods in respect to viral sewage metagenomics, hampering the development of this field. By the use of next generation sequencing this study aimed to evaluate the efficiency of four commonly applied viral concentrations techniques (precipitation with polyethylene glycol, organic flocculation with skim milk, monolithic adsorption filtration and glass wool filtration) and extraction methods (Nucleospin RNA XS, QIAamp Viral RNA Mini Kit, NucliSENSÂź miniMAGÂź, or PowerViralÂź Environmental RNA/DNA Isolation Kit) to determine the viriome in a sewage sample. We found a significant influence of concentration and extraction protocols on the detected viriome. The viral richness was largest in samples extracted with QIAamp Viral RNA Mini Kit or PowerViralÂź Environmental RNA/DNA Isolation Kit. Highest viral specificity were found in samples concentrated by precipitation with polyethylene glycol or extracted with Nucleospin RNA XS. Detection of viral pathogens depended on the method used. These results contribute to the understanding of method associated biases, within the field of viral sewage metagenomics, making evaluation of the current literature easier and helping with the design of future studies
All-sky Search for High-Energy Neutrinos from Gravitational Wave Event GW170104 with the ANTARES Neutrino Telescope
Advanced LIGO detected a significant gravitational wave signal (GW170104)
originating from the coalescence of two black holes during the second
observation run on January 4, 2017. An all-sky high-energy
neutrino follow-up search has been made using data from the ANTARES neutrino
telescope, including both upgoing and downgoing events in two separate
analyses. No neutrino candidates were found within s around the GW
event time nor any time clustering of events over an extended time window of
months. The non-detection is used to constrain isotropic-equivalent
high-energy neutrino emission from GW170104 to less than
erg for a spectrum
The Antares Collaboration : Contributions to the 34th International Cosmic Ray Conference (ICRC 2015, The Hague)
The ANTARES detector, completed in 2008, is the largest neutrino telescope in the Northern hemisphere. Located at a depth of 2.5 km in the Mediterranean Sea, 40 km off the Toulon shore, its main goal is the search for astrophysical high energy neutrinos. In this paper we collect the 21 contributions of the ANTARES collaboration to the 34th International Cosmic Ray Conference (ICRC 2015). The scientific output is very rich and the contributions included in these proceedings cover the main physics results, ranging from steady point sources, diffuse searches, multi-messenger analyses to exotic physics
The ANTARES Collaboration: Contributions to ICRC 2017 Part I: Neutrino astronomy (diffuse fluxes and point sources)
Papers on neutrino astronomy (diffuse fluxes and point sources, prepared for
the 35th International Cosmic Ray Conference (ICRC 2017, Busan, South Korea) by
the ANTARES Collaboratio
The ANTARES Collaboration: Contributions to ICRC 2017 Part III: Searches for dark matter and exotics, neutrino oscillations and detector calibration
Papers on the searches for dark matter and exotics, neutrino oscillations and
detector calibration, prepared for the 35th International Cosmic Ray Conference
(ICRC 2017, Busan, South Korea) by the ANTARES Collaboratio
The ANTARES Collaboration: Contributions to ICRC 2017 Part II: The multi-messenger program
Papers on the ANTARES multi-messenger program, prepared for the 35th
International Cosmic Ray Conference (ICRC 2017, Busan, South Korea) by the
ANTARES Collaboratio
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