440 research outputs found
xURLLC in 6G with meshed RAN
5G Ultra-Reliable Low Latency Communications Technology (URLLC) will not be able to provide extremely reliable low latency services to the complex networks in 6G. Moreover, URLLC that began with 5G has to be refined and improved in 6G to provide xURLCC (extreme URLCC) with sub-millisecond latency, for supporting diverse mission-critical applications. This paper aims to highlight the importance of peer-to-peer mesh connectivity for services that require xURLLC. Deploying mesh connectivity among RAN nodes would add significant value to the current 5G New Radio (5G NR) enabling 6G to increase flexibility and reliability of the networks while reducing the inherent latency introduced by the core network. To provide a mesh connectivity in RAN, the nodes should be able to communicate with each other directly and be independent from the mobile core network so that data can be directly exchanged between base stations (gNBs) whereas certain aspects of signalling procedure including data session establishment will be managed by RAN itself. In this paper, we introduce several architectural choices for a mesh network topology that could potentially be crucial to a number of applications. In addition, three possible options to create mesh connectivity in RAN are provided, and their pros and cons are discussed in detail
The 2016 outburst of PSR J1119-6127: cooling & a spin-down dominated glitch
We report on the aftermath of a magnetar outburst from the young,
high-magnetic-field radio pulsar PSR J1119-6127 that occurred on 2016 July 27.
We present the results of a monitoring campaign using the Neil Gehrels Swift
X-ray Telescope, NuSTAR, and XMM-Newton. After reaching a peak luminosity of
~300 times the quiescent luminosity, the pulsar's X-ray flux declined by factor
of ~50 on a time scale of several months. The X-ray spectra are well described
by a blackbody and a hard power-law tail. After an initial rapid decline during
the first day of the outburst, we observe the blackbody temperature rising from
kT = 0.9 keV to 1.05 keV during the first two weeks of the outburst, before
cooling to 0.9 keV. During this time, the blackbody radius decreases
monotonically by a factor of ~4 over a span of nearly 200 days. We also report
a heretofore unseen highly pulsed hard X-ray emission component, which fades on
a similar timescale to the soft X-ray flux, as predicted by models of
relaxation of magnetospheric current twists. The previously reported spin-up
glitch which accompanied this outburst was followed by a period of enhanced and
erratic torque, leading to a net spin-down of Hz, a
factor of ~24 over-recovery. We suggest that this and other radiatively loud
magnetar-type glitch recoveries are dominated by magnetospheric processes, in
contrast to conventional radio pulsar glitch recoveries which are dominated by
internal physics.Comment: Submitted to Ap
PLAN2L: a web tool for integrated text mining and literature-based bioentity relation extraction
There is an increasing interest in using literature mining techniques to complement information extracted from annotation databases or generated by bioinformatics applications. Here we present PLAN2L, a web-based online search system that integrates text mining and information extraction techniques to access systematically information useful for analyzing genetic, cellular and molecular aspects of the plant model organism Arabidopsis thaliana. Our system facilitates a more efficient retrieval of information relevant to heterogeneous biological topics, from implications in biological relationships at the level of protein interactions and gene regulation, to sub-cellular locations of gene products and associations to cellular and developmental processes, i.e. cell cycle, flowering, root, leaf and seed development. Beyond single entities, also predefined pairs of entities can be provided as queries for which literature-derived relations together with textual evidences are returned. PLAN2L does not require registration and is freely accessible at http://zope.bioinfo.cnio.es/plan2l
High-efficiency Autonomous Laser Adaptive Optics
As new large-scale astronomical surveys greatly increase the number of
objects targeted and discoveries made, the requirement for efficient follow-up
observations is crucial. Adaptive optics imaging, which compensates for the
image-blurring effects of Earth's turbulent atmosphere, is essential for these
surveys, but the scarcity, complexity and high demand of current systems limits
their availability for following up large numbers of targets. To address this
need, we have engineered and implemented Robo-AO, a fully autonomous laser
adaptive optics and imaging system that routinely images over 200 objects per
night with an acuity 10 times sharper at visible wavelengths than typically
possible from the ground. By greatly improving the angular resolution,
sensitivity, and efficiency of 1-3 m class telescopes, we have eliminated a
major obstacle in the follow-up of the discoveries from current and future
large astronomical surveys.Comment: Published in ApJL. 6 pages, 4 figures, and 1 tabl
The Rise of SN 2014J in the Nearby Galaxy M82
We report on the discovery of SN 2014J in the nearby galaxy M82. Given its proximity, it offers the best opportunity to date to study a thermonuclear supernova (SN) over a wide range of the electromagnetic spectrum. Optical, near-IR, and mid-IR observations on the rising light curve, orchestrated by the intermediate Palomar Transient Factory, show that SN 2014J is a spectroscopically normal Type Ia supernova (SN Ia), albeit exhibiting high-velocity features in its spectrum and heavily reddened by dust in the host galaxy. Our earliest detections start just hours after the fitted time of explosion. We use high-resolution optical spectroscopy to analyze the dense intervening material and do not detect any evolution in the resolved absorption features during the light curve rise. Similar to other highly reddened SNe Ia, a low value of total-to-selective extinction, R_V ā² 2, provides the best match to our observations. We also study pre-explosion optical and near-IR images from Hubble Space Telescope with special emphasis on the sources nearest to the SN location
Phase-resolved NuSTAR and Swift-XRT Observations of Magnetar 4U 0142+61
We present temporal and spectral analysis of simultaneous 0.5-79 keV
Swift-XRT and NuSTAR observations of the magnetar 4U 0142+61. The pulse profile
changes significantly with photon energy between 3 and 35 keV. The pulse
fraction increases with energy, reaching a value of ~20%, similar to that
observed in 1E 1841-045 and much lower than the ~80% pulse fraction observed in
1E 2259+586. We do not detect the 55-ks phase modulation reported in previous
Suzaku-HXD observations. The phase-averaged spectrum of 4U 0142+61 above 20 keV
is dominated by a hard power law with a photon index, ~ 0.65, and the
spectrum below 20 keV can be described by two blackbodies, a blackbody plus a
soft power law, or by a Comptonized blackbody model. We study the full
phase-resolved spectra using the electron-positron outflow model of Beloborodov
(2013). Our results are consistent with the parameters of the active j-bundle
derived from INTEGRAL data by Hascoet et al. (2014). We find that a significant
degeneracy appears in the inferred parameters if the footprint of the j-bundle
is allowed to be a thin ring instead of a polar cap. The degeneracy is reduced
when the footprint is required to be the hot spot inferred from the soft X-ray
data.Comment: 14 pages, 8 figures, 4 tables. Accepted for publication in Ap
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