3,337 research outputs found
SECOR observations in the Pacific
Geometric adjustment technique for Pacific SECOR observations based on least squares metho
North American datum in view of Geos 1 observations
Determination of North America datum by GEOS 1 satellite observation
On-Chip Microwave Quantum Hall Circulator
Circulators are non-reciprocal circuit elements integral to technologies
including radar systems, microwave communication transceivers, and the readout
of quantum information devices. Their non-reciprocity arises from the
interference of microwaves over the centimetre-scale of the signal wavelength
in the presence of bulky magnetic media that break time-reversal symmetry. Here
we realize a completely passive on-chip microwave circulator with size
one-thousandth the wavelength by exploiting the chiral, slow-light response of
a 2-dimensional electron gas (2DEG) in the quantum Hall regime. For an
integrated GaAs device with 330 um diameter and 1 GHz centre frequency, a
non-reciprocity of 25 dB is observed over a 50 MHz bandwidth. Furthermore, the
direction of circulation can be selected dynamically by varying the magnetic
field, an aspect that may enable reconfigurable passive routing of microwave
signals on-chip
Autism spectrum disorder in children and young people with non-epileptic seizures
Purpose:
Non-epileptic seizures are paroxysmal events which to an observer resemble epileptic seizures. Proposed risk factors incorporate biopsychosocial aspects including factors in the affected individual. Unexpectedly high rates of autism spectrum disorder (ASD) occurred in the clinical population reported here. Although elevated levels of psychiatric co-morbidity are known to be present in patients with NES, ASD has only been previously described in a single case report. /
Methods:
This case series captures rates of ASD in 59 children and young people who were referred to a specialist paediatric mental health service at Great Ormond Street Hospital, London, UK for assessment and treatment of non-epileptic seizures between 2012 and 2016. /
Results:
10/59 (16.9%) of the children and young people with non-epileptic seizures also had ASD, with 5/10 (50%) of these undiagnosed with ASD before referral. Children and young people with ASD were significantly more likely to have tics or attention-deficit hyperactivity disorder than those without ASD. /
Conclusion:
ASD may be a common co-morbidity in non-epileptic seizures. Careful clinical assessment with consideration of ASD traits is therefore important in the non-epileptic seizures population. It is beneficial to diagnose ASD early as its presence is likely to require a modified approach to assessment and treatment of non-epileptic seizures. Study of the development of non-epileptic seizures in ASD may suggest hypotheses for the pathogenesis of non-epileptic seizures in the wider population
Transport through quasi-ballistic quantum wires: the role of contacts
We model one-dimensional transport through each open channel of a quantum
wire by a Luttinger liquid with three different interaction parameters for the
leads, the contact regions and the wire, and with two barriers at the contacts.
We show that this model explains several features of recent experiments, such
as the flat conductance plateaux observed even at finite temperatures and for
different lengths, and universal conductance corrections in different channels.
We discuss the possibility of seeing resonance-like structures of a fully open
channel at very low temperatures.Comment: revtex, 5 pages, 1 eps figure; clarifications added in light of new
experiment
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