2,826 research outputs found
Symmetries and collective excitations in large superconducting circuits
The intriguing appeal of circuits lies in their modularity and ease of
fabrication. Based on a toolbox of simple building blocks, circuits present a
powerful framework for achieving new functionality by combining circuit
elements into larger networks. It is an open question to what degree modularity
also holds for quantum circuits -- circuits made of superconducting material,
in which electric voltages and currents are governed by the laws of quantum
physics. If realizable, quantum coherence in larger circuit networks has great
potential for advances in quantum information processing including topological
protection from decoherence. Here, we present theory suitable for quantitative
modeling of such large circuits and discuss its application to the fluxonium
device. Our approach makes use of approximate symmetries exhibited by the
circuit, and enables us to obtain new predictions for the energy spectrum of
the fluxonium device which can be tested with current experimental technology
A three-dimensional finite element model of maximal grip loading in the human wrist
The aim of this work was to create an anatomically accurate three-dimensional finite element model of the wrist, applying subject-specific loading and quantifying the internal load transfer through the joint during maximal grip. For three subjects, representing the anatomical variation at the wrist, loading on each digit was measured during a maximal grip strength test with simultaneous motion capture. The internal metacarpophalangeal joint load was calculated using a biomechanical model. High-resolution magnetic resonance scans were acquired to quantify bone geometry. Finite element analysis was performed, with ligaments and tendons added, to calculate the internal load distribution. It was found that for the maximal grip the thumb carried the highest load, an average of 72.2 ¡ 20.1 N in the neutral position. Results from the finite element model suggested that the highest regions of stress were located at the radial aspect of the carpus. Most of the load was transmitted through the radius, 87.5 per cent, as opposed to 12.5 per cent through the ulna with the wrist in a neutral position. A fully three-dimensional finite element analysis of the wrist using subject-specific anatomy and loading conditions was performed. The study emphasizes the importance of modelling a large ensemble of subjects in order to capture the spectrum of the load transfer through the wrist due to anatomical variation
More evidence for extinction of activity in galaxies
This Research Note amends an article in which we showed that radio-loud
quasars can become radio-quiet. Exploring the analogy between galactic nuclei
and X-ray binaries (XRB), we pointed out there that this transition in quasars
could be identified with a switch from low/hard to high/soft state in
microquasars. Here, we present the evidence that traces of past occurrences of
this kind of phenomena can be found in normal but once active galaxies. Based
on the properties of a few such "post-active" galaxies that are representative
for a much wider group, it has been argued that they have reached the
evolutionary stages when their nuclei, which were radio-loud in the past, now,
mimicking the behaviour of XRBs, remain in the intermediate state on their way
towards quiescence or even have already entered the quiescent state. It follows
that the full evolutionary track of XRBs can be mapped onto the evolution of
galaxies. The above findings are in line with those reported recently for IC
2497, a galaxy that 70,000 years ago or less hosted a quasar but now appears as
a normal one. This scenario stems from the presence of Hanny's Voorwerp, a
nebulous object in its vicinity excited by that QSO in the epoch when IC 2497
was active. The post-active galaxies we deal with here are accompanied by
extremely weak and diffuse relic radio lobes that were inflated during their
former active period. These relics can be regarded as radio analogues of
Hanny's Voorwerp.Comment: 10 pages, 6 figures, A&A in pres
Towards Data Literacy Competencies: business students, workforce needs, and the role of the librarian
Companies are looking to harness the power of data, both big and small, to take their business to new levels. One major hurdle for companies seeking to become data-centric is facing a lack of data literate talent for hire in the current market of recent college graduates. This article establishes a conversation about data literacy in business education, discusses the role of the librarian in this work, and proposes a set of data literacy competencies that librarians could help incorporate into business school education, as has been similarly seen in other disciplines
SINFONI's take on Star Formation, Molecular Gas, and Black Hole Masses in AGN
We present some preliminary (half-way) results on our adaptive optics
spectroscopic survey of AGN at spatial scales down to 0.085arcsec. Most of the
data were obtained with SINFONI which provides integral field capability at a
spectral resolution of R~4000. The themes on which we focus in this
contribution are: star formation around the AGN, the properties of the
molecular gas and its relation to the torus, and the mass of the black hole.Comment: 5 pages, 2 figures. To appear in Science Perspectives for 3D
Spectroscopy. ESO Astrophysics Symposia. Ed by M. Kissler-Patig, M. Roth and
J. Wals
Sub-Milliarcsecond Precision of Pulsar Motions: Using In-Beam Calibrators with the VLBA
We present Very Long Baseline Array phase-referenced measurements of the
parallax and proper motion of two pulsars, B0919+06 and B1857-26.
Sub-milliarcsecond positional accuracy was obtained by simultaneously observing
a weak calibrator source within the 40' field of view of the VLBA at 1.5 GHz.
We discuss the merits of using weak close calibrator sources for VLBI
observations at low frequencies, and outline a method of observation and data
reduction for these type of measurements. For the pulsar B1919+06 we measure a
parallax of 0.31 +/- 0.14 mas. The accuracy of the proper motions is
approximately 0.5 mas, an order of magnitude improvement over most previous
determinations.Comment: 11 pages plus 4 figures. In press, Astronomical Journa
- …