1,343 research outputs found
Learning Occupational Task-Shares Dynamics for the Future of Work
The recent wave of AI and automation has been argued to differ from previous
General Purpose Technologies (GPTs), in that it may lead to rapid change in
occupations' underlying task requirements and persistent technological
unemployment. In this paper, we apply a novel methodology of dynamic task
shares to a large dataset of online job postings to explore how exactly
occupational task demands have changed over the past decade of AI innovation,
especially across high, mid and low wage occupations. Notably, big data and AI
have risen significantly among high wage occupations since 2012 and 2016,
respectively. We built an ARIMA model to predict future occupational task
demands and showcase several relevant examples in Healthcare, Administration,
and IT. Such task demands predictions across occupations will play a pivotal
role in retraining the workforce of the future.Comment: 9 pages, 5 figures, 6 tables, Proceedings of the AAAI/ACM Conference
on AI, Ethics, and Society (AIES), 202
Signatures of helical jets
Observational signatures of helical jets can be found in some X-ray binaries
(XRB), planetary nebulae, Herbig-Haro objects and in jets of active galactic
nuclei (AGN). For the prototypical XRB SS433 a kinematic model of precessing
jets has been applied very successfully and yielded a determination of its
distance which is independent of conventional methods. In galactic jets
precession appears to be the predominant mechanism for the production of
observed helical signatures. In extragalactic jets other mechanisms seem to be
similarly frequent. As a result of their strong dependence on the direction of
motion with respect to the observer, special relativistic effects can be
pronounced in helical jets. These have to be taken into account in AGN-jets and
the newly discovered galactic sources which show apparent superluminal motion.
Since the galactic superluminal jets are located in a binary system, jet
precession is very likely in these sources. In this paper I review the main
structural and kinematic signatures of helical jets and briefly mention the
physical mechanisms behind them. I will present kinematic simulations of
relativistic jets which are helically bent or have an internal helical flow
field.Comment: Contribution to the proceedings of a workshop on 'Relativistic Jets
in X-ray binaries" held in Jodrell Bank, UK, 1996; to be published in 'Vistas
in Astronomy
Interaction of radio jets with clouds in the ambient medium: Numerical simulations
Hydrodynamical simulations of jets interacting with clouds moving in the
ambient medium of the host galaxy are presented. Clouds with sizes of the order
of the jet diameter and smaller, crossing the path of the jet with different
speeds are considered. In the case of slow moving clouds the jet is stopped
over the brief period of time taken by the cloud to cross the jet. The jet
maintains its general morphology in the case of fast moving clouds. Erosion of
the clouds leads to redistribution of cloud material to large distances. Such
interaction may explain the large outflow velocities observed from pc to kpc
scales in the compact radio sources.Comment: 4 pages, to appear in the Proceedings of "The 4th CSS/GPS Workshop
Determinants of left ventricular mass in obesity; a cardiovascular magnetic resonance study
<p>Abstract</p> <p>Background</p> <p>Obesity is linked to increased left ventricular mass, an independent predictor of mortality. As a result of this, understanding the determinants of left ventricular mass in the setting of obesity has both therapeutic and prognostic implications. Using cardiovascular magnetic resonance our goal was to elucidate the main predictors of left ventricular mass in severely obese subjects free of additional cardiovascular risk factors.</p> <p>Methods</p> <p>38 obese (BMI 37.8 ± 6.9 kg/m<sup>2</sup>) and 16 normal weight controls subjects, (BMI 21.7 ± 1.8 kg/m<sup>2</sup>), all without cardiovascular risk factors, underwent cardiovascular magnetic resonance imaging to assess left ventricular mass, left ventricular volumes and visceral fat mass. Left ventricular mass was then compared to serum and anthropometric markers of obesity linked to left ventricular mass, i.e. height, age, blood pressure, total fat mass, visceral fat mass, lean mass, serum leptin and fasting insulin level.</p> <p>Results</p> <p>As expected, obesity was associated with significantly increased left ventricular mass (126 ± 27 vs 90 ± 20 g; p < 0.001). Stepwise multiple regression analysis showed that over 75% of the cross sectional variation in left ventricular mass can be explained by lean body mass (β = 0.51, p < 0.001), LV stroke volume (β = 0.31 p = 0.001) and abdominal visceral fat mass (β = 0.20, p = 0.02), all of which showed highly significant independent associations with left ventricular mass (overall R<sup>2 </sup>= 0.77).</p> <p>Conclusion</p> <p>The left ventricular hypertrophic response to obesity in the absence of additional cardiovascular risk factors is mainly attributable to increases in lean body mass, LV stroke volume and visceral fat mass. In view of the well documented link between obesity, left ventricular hypertrophy and mortality, these findings have potentially important prognostic and therapeutic implications for primary and secondary prevention.</p
When are prime formulae characteristic?
In the setting of the modal logic that characterizes modal refinement over modal transition systems, Boudol and Larsen showed that the formulae for which model checking can be reduced to preorder checking, that is, the characteristic formulae, are exactly the consistent and prime ones. This paper presents general, sufficient conditions guaranteeing that characteristic formulae are exactly the consistent and prime ones. It is shown that the given conditions apply to the logics characterizing all the semantics in van Glabbeek's branching-time spectrum
Steady state entanglement of two coupled qubits
The maximum entanglement between two coupled qubits in the steady state under
two independent incoherent sources of excitation is reported. Asymmetric
configurations where one qubit is excited while the other one dissipates the
excitation are optimal for entanglement, reaching values three times larger
than with thermal sources. The reason is the purification of the steady state
mixture (that includes a Bell state) thanks to the saturation of the pumped
qubit. Photon antibunching between the cross emission of the qubits can be used
to experimentally evidence the large degrees of entanglement.Comment: 7 pages, 5 figure
Life after charge noise: recent results with transmon qubits
We review the main theoretical and experimental results for the transmon, a
superconducting charge qubit derived from the Cooper pair box. The increased
ratio of the Josephson to charging energy results in an exponential suppression
of the transmon's sensitivity to 1/f charge noise. This has been observed
experimentally and yields homogeneous broadening, negligible pure dephasing,
and long coherence times of up to 3 microseconds. Anharmonicity of the energy
spectrum is required for qubit operation, and has been proven to be sufficient
in transmon devices. Transmons have been implemented in a wide array of
experiments, demonstrating consistent and reproducible results in very good
agreement with theory.Comment: 6 pages, 4 figures. Review article, accepted for publication in
Quantum Inf. Pro
Generation of Three-Qubit Entangled States using Superconducting Phase Qubits
Entanglement is one of the key resources required for quantum computation, so
experimentally creating and measuring entangled states is of crucial importance
in the various physical implementations of a quantum computer. In
superconducting qubits, two-qubit entangled states have been demonstrated and
used to show violations of Bell's Inequality and to implement simple quantum
algorithms. Unlike the two-qubit case, however, where all maximally-entangled
two-qubit states are equivalent up to local changes of basis, three qubits can
be entangled in two fundamentally different ways, typified by the states
and . Here we demonstrate the operation of three coupled
superconducting phase qubits and use them to create and measure
and states. The states are fully characterized
using quantum state tomography and are shown to satisfy entanglement witnesses,
confirming that they are indeed examples of three-qubit entanglement and are
not separable into mixtures of two-qubit entanglement.Comment: 9 pages, 5 figures. Version 2: added supplementary information and
fixed image distortion in Figure 2
Preparation and Measurement of Three-Qubit Entanglement in a Superconducting Circuit
Traditionally, quantum entanglement has played a central role in foundational
discussions of quantum mechanics. The measurement of correlations between
entangled particles can exhibit results at odds with classical behavior. These
discrepancies increase exponentially with the number of entangled particles.
When entanglement is extended from just two quantum bits (qubits) to three, the
incompatibilities between classical and quantum correlation properties can
change from a violation of inequalities involving statistical averages to sign
differences in deterministic observations. With the ample confirmation of
quantum mechanical predictions by experiments, entanglement has evolved from a
philosophical conundrum to a key resource for quantum-based technologies, like
quantum cryptography and computation. In particular, maximal entanglement of
more than two qubits is crucial to the implementation of quantum error
correction protocols. While entanglement of up to 3, 5, and 8 qubits has been
demonstrated among spins, photons, and ions, respectively, entanglement in
engineered solid-state systems has been limited to two qubits. Here, we
demonstrate three-qubit entanglement in a superconducting circuit, creating
Greenberger-Horne-Zeilinger (GHZ) states with fidelity of 88%, measured with
quantum state tomography. Several entanglement witnesses show violation of
bi-separable bounds by 830\pm80%. Our entangling sequence realizes the first
step of basic quantum error correction, namely the encoding of a logical qubit
into a manifold of GHZ-like states using a repetition code. The integration of
encoding, decoding and error-correcting steps in a feedback loop will be the
next milestone for quantum computing with integrated circuits.Comment: 7 pages, 4 figures, and Supplementary Information (4 figures)
- …