258 research outputs found
Bright burst detections from FRB 20220912A at 332 MHz using the Westerbork-RT1 25-m telescope
Bright burst detections from FRB 20220912A at 332 MHz using the Westerbork-RT1 25-m telescope
A fast radio burst with a low dispersion measure
Fast radio bursts (FRBs) are millisecond pulses of radio emission of
seemingly extragalactic origin. More than 50 FRBs have now been detected, with
only one seen to repeat. Here we present a new FRB discovery, FRB 110214, which
was detected in the high latitude portion of the High Time Resolution Universe
South survey at the Parkes telescope. FRB 110214 has one of the lowest
dispersion measures of any known FRB (DM = 168.90.5 pc cm), and was
detected in two beams of the Parkes multi-beam receiver. A triangulation of the
burst origin on the sky identified three possible regions in the beam pattern
where it may have originated, all in sidelobes of the primary detection beam.
Depending on the true location of the burst the intrinsic fluence is estimated
to fall in the range of 50 -- 2000 Jy ms, making FRB 110214 one of the
highest-fluence FRBs detected with the Parkes telescope. No repeating pulses
were seen in almost 100 hours of follow-up observations with the Parkes
telescope down to a limiting fluence of 0.3 Jy ms for a 2-ms pulse. Similar
low-DM, ultra-bright FRBs may be detected in telescope sidelobes in the future,
making careful modeling of multi-beam instrument beam patterns of utmost
importance for upcoming FRB surveys.Comment: 8 pages, 3 figures, accepted for publication in MNRA
Heterogeneous Delays in Neural Networks
We investigate heterogeneous coupling delays in complex networks of excitable
elements described by the FitzHugh-Nagumo model. The effects of discrete as
well as of uni- and bimodal continuous distributions are studied with a focus
on different topologies, i.e., regular, small-world, and random networks. In
the case of two discrete delay times resonance effects play a major role:
Depending on the ratio of the delay times, various characteristic spiking
scenarios, such as coherent or asynchronous spiking, arise. For continuous
delay distributions different dynamical patterns emerge depending on the width
of the distribution. For small distribution widths, we find highly synchronized
spiking, while for intermediate widths only spiking with low degree of
synchrony persists, which is associated with traveling disruptions, partial
amplitude death, or subnetwork synchronization, depending sensitively on the
network topology. If the inhomogeneity of the coupling delays becomes too
large, global amplitude death is induced
Synchronisation in networks of delay-coupled type-I excitable systems
We use a generic model for type-I excitability (known as the SNIPER or SNIC
model) to describe the local dynamics of nodes within a network in the presence
of non-zero coupling delays. Utilising the method of the Master Stability
Function, we investigate the stability of the zero-lag synchronised dynamics of
the network nodes and its dependence on the two coupling parameters, namely the
coupling strength and delay time. Unlike in the FitzHugh-Nagumo model (a model
for type-II excitability), there are parameter ranges where the stability of
synchronisation depends on the coupling strength and delay time. One important
implication of these results is that there exist complex networks for which the
adding of inhibitory links in a small-world fashion may not only lead to a loss
of stable synchronisation, but may also restabilise synchronisation or
introduce multiple transitions between synchronisation and desynchronisation.
To underline the scope of our results, we show using the Stuart-Landau model
that such multiple transitions do not only occur in excitable systems, but also
in oscillatory ones.Comment: 10 pages, 9 figure
Mycobacterium tuberculosis phagosome
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75241/1/j.1365-2958.1999.01279.x.pd
The High Time Resolution Universe survey:XIV. Discovery of 23 pulsars through GPU-accelerated reprocessing
Directed flow in Au+Au, Xe+CsI and Ni+Ni collisions and the nuclear equation of state
We present new experimental data on directed flow in collisions of Au+Au,
Xe+CsI and Ni+Ni at incident energies from 90 to 400A MeV. We study the
centrality and system dependence of integral and differential directed flow for
particles selected according to charge. All the features of the experimental
data are compared with Isospin Quantum Molecular Dynamics (IQMD) model
calculations in an attempt to extract information about the nuclear matter
equation of state (EoS). We show that the combination of rapidity and
transverse momentum analysis of directed flow allow to disentangle various
parametrizations in the model. At 400A MeV, a soft EoS with momentum dependent
interactions is best suited to explain the experimental data in Au+Au and
Xe+CsI, but in case of Ni+Ni the model underpredicts flow for any EoS. At 90A
MeV incident beam energy, none of the IQMD parametrizations studied here is
able to consistently explain the experimental data.Comment: RevTeX, 20 pages, 30 eps figures, accepted for publication in Phys.
Rev. C. Data files available at http://www.gsi.de/~fopiwww/pub
Increasing importance of anthelmintic resistance in European livestock: creation and meta-analysis of an open database
Trabajo presentado al: COMBAR meeting (Combatting Anthelmintic Resistance in Ruminants). Atenas (Grecia). Febrero. 2022
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