1,746 research outputs found
LEDFD: A Low Energy Consumption Distributed Fault Detection Algorithm for Wireless Sensor Networks
Detection of faulty nodes and network energy saving have become the hottest research topics. Furthermore, current fault detection algorithms always pursue high detection performance but neglect energy consumption. In order to obtain good fault detection performance and save the network power, this paper proposes a low energy consumption distributed fault detection algorithm (LEDFD), which takes full advantage of temporally correlated and spatially correlated characteristics of the sensor nodes. LEDFD utilizes the temporally correlated information to examine some faulty nodes and then utilizes the spatially correlated information to examine the nodes that have not been detected as faulty through exchanging information among neighbor nodes to determine those nodes' state. Because LEDFD takes the data produced by nodes themselves to detect certain types of faults, which means nodes need not exchange information with their neighbor nodes during the entire detection process, the energy consumption of networks is efficiently reduced. Experimental results show that the algorithm has good performance and low energy consumption compared with current algorithms. </jats:p
Synthetic X-ray and radio maps for two different models of Stephan's Quintet
We present simulations of the compact galaxy group Stephan's Quintet (SQ)
including magnetic fields, performed with the N-body/smoothed particle
hydrodynamics (SPH) code \textsc{Gadget}. The simulations include radiative
cooling, star formation and supernova feedback. Magnetohydrodynamics (MHD) is
implemented using the standard smoothed particle magnetohydrodynamics (SPMHD)
method. We adapt two different initial models for SQ based on Renaud et al. and
Hwang et al., both including four galaxies (NGC 7319, NGC 7320c, NGC 7318a and
NGC 7318b). Additionally, the galaxies are embedded in a magnetized, low
density intergalactic medium (IGM). The ambient IGM has an initial magnetic
field of G and the four progenitor discs have initial magnetic fields
of G. We investigate the morphology, regions of star
formation, temperature, X-ray emission, magnetic field structure and radio
emission within the two different SQ models. In general, the enhancement and
propagation of the studied gaseous properties (temperature, X-ray emission,
magnetic field strength and synchrotron intensity) is more efficient for the SQ
model based on Renaud et al., whose galaxies are more massive, whereas the less
massive SQ model based on Hwang et al. shows generally similar effects but with
smaller efficiency. We show that the large shock found in observations of SQ is
most likely the result of a collision of the galaxy NGC 7318b with the IGM.
This large group-wide shock is clearly visible in the X-ray emission and
synchrotron intensity within the simulations of both SQ models. The order of
magnitude of the observed synchrotron emission within the shock front is
slightly better reproduced by the SQ model based on Renaud et al., whereas the
distribution and structure of the synchrotron emission is better reproduced by
the SQ model based on Hwang et al..Comment: 20 pages, 15 figures, accepted to MNRA
Trapping of Rb atoms by ac electric fields
We demonstrate trapping of an ultracold gas of neutral atoms in a macroscopic
ac electric trap. Three-dimensional confinement is obtained by switching
between two saddle-point configurations of the electric field. Stable trapping
is observed in a narrow range of switching frequencies around 60 Hz. The
dynamic confinement of the atoms is directly visualized at different phases of
the ac switching cycle. We observe about 10^5 Rb atoms in the 1 mm^3 large and
several microkelvins deep trap with a lifetime of approximately 5 s.Comment: 4 pages, 4 figures; updated version, added journal referenc
Origin and evolution of lysyl oxidases
Lysyl oxidases (LOX) are copper-dependent enzymes that oxidize primary amine substrates to reactive aldehydes. The best-studied role of LOX enzymes is the remodeling of the extracellular matrix (ECM) in animals by cross-linking collagens and elastin, although intracellular functions have been reported as well. Five different LOX enzymes have been identified in mammals, LOX and LOX-like (LOXL) 1 to 4, showing a highly conserved catalytic carboxy terminal domain and more divergence in the rest of the sequence. Here we have surveyed a wide selection of genomes in order to infer the evolutionary history of LOX. We identified LOX proteins not only in animals, but also in many other eukaryotes, as well as in bacteria and archaea - which reveals a pre-metazoan origin for this gene family. LOX genes expanded during metazoan evolution resulting in two superfamilies, LOXL2/L3/L4 and LOX/L1/L5. Considering the current knowledge on the function of mammalian LOX isoforms in ECM remodeling, we propose that LOXL2/L3/L4 members might have preferentially been involved in making cross-linked collagen IV-based basement membrane, whereas the diversification of LOX/L1/L5 forms contributed to chordate/vertebrate-specific ECM innovations, such as elastin and fibronectin. Our work provides a novel view on the evolution of this family of enzymes.This work was supported by grants from Ministerio de EconomÃa y Competitividad (MINECO; Plan Nacional de I+ D+ I: SAF2012-34916 to F.R-P., BFU2011-23434 to I.R.-T.); Comunidad Autónoma de Madrid (2010-BMD2321, FIBROTEAM Consortium to F.R-P.); Secretaria d’Universitats i Recerca del Departament d’Economia i Coneixement de la Generalitat de Catalunya (2014 SGR 619 to I.R.-T.) and European Research Council Starting Grant (ERC-2012-Co-616960 to I.R.-T.). X.G.-B. is supported by a pregraduate Formación del Personal Investigador grant from MINECO.Peer Reviewe
Accurate relativistic chiral nucleon-nucleon interaction up to NNLO
We construct a relativistic chiral nucleon-nucleon interaction up to the
next-to-next-to-leading order in covariant baryon chiral perturbation theory.
We show that a good description of the phase shifts up to
MeV and even higher can be achieved with a
less than 1. Both the next-to-leading order
results and the next-to-next-to-leading order results describe the phase shifts
equally well up to MeV, but for higher energies, the
latter behaves better, showing satisfactory convergence. The relativistic
chiral potential provides the most essential inputs for relativistic ab initio
studies of nuclear structure and reactions, which has been in need for almost
two decades.Comment: Accepted for publication in PRL. Uncertainty estimates updated and
comparison with the Granada PWA adde
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