17,929 research outputs found
Bell inequalities for continuous-variable correlations
We derive a new class of correlation Bell-type inequalities. The inequalities
are valid for any number of outcomes of two observables per each of n parties,
including continuous and unbounded observables. We show that there are no
first-moment correlation Bell inequalities for that scenario, but such
inequalities can be found if one considers at least second moments. The
derivation stems from a simple variance inequality by setting local commutators
to zero. We show that above a constant detector efficiency threshold, the
continuous variable Bell violation can survive even in the macroscopic limit of
large n. This method can be used to derive other well-known Bell inequalities,
shedding new light on the importance of non-commutativity for violations of
local realism.Comment: 4 pages, 1 figure. v2: New results on detector efficiencies and
macroscopic limit, new co-author, changed title and abstract, changed figure,
added journal reference and DO
The Facilitation of Learning Groups: A Study of a Dairy Discussion Group Facilitator
Farm Management,
Retransmission of hydrometric data in Canada
The author has identified the following significant results. The project continues to demonstrate the feasibility of transmitting hydrometric data to polar orbiting spacecraft and using these data operationally. All elements on the system are functioning well
Three newly-discovered M-dwarf companions of Solar Neighbourhood stars
We present low-resolution spectroscopy of newly-discovered candidate
companions to three stars in the Solar Neighbourhood. All three companions are
M dwarfs, with spectral types ranging from M4 to M9.5. In two cases, G85-55`B'
(M6) and G87-9`B' (M4), we have circumstantial evidence from spectroscopy,
photometry and limited astrometry that the systems are physical binaries; in
the third, G216-7B (M9.5), comparison of POSS II IIIaF plate material and the
2MASS image indicates common proper motion. The primary star in this system,
G216-7A (M0), appears itself to be an unresolved, nearly equal-mass binary. All
three low-mass companions are highly likely to be stellar in nature, although
G216-7B lies very close to the hydrogen-burning limit.Comment: Accepted for publication in PASP; 21 pages, 6 figure
Mesospheric turbulent velocity estimation using the Buckland Park MF radar
Copyright © 2001 European Geosciences UnionThis paper investigates turbulent velocity estimation using the full correlation analysis (FCA) of spaced antenna (SA) data, and its application to the routine FCA observations of the Buckland Park MF (BPMF) radar. The effects of transmitter beamwidths are investigated, confirming the suggestions of previous authors that wide transmit beam widths lead to an overestimation of the turbulent velocity. The annual variation of the turbulent velocity is investigated, revealing an increase in turbulent velocity with height, and equinoctal minima and solstice maxima observed below 80 km. Investigations of the turbulent velocities about the March diurnal tide maximum reveals a diurnal variation in phase with the zonal velocity. Harmonic analysis reveals this relationship exists between February and September. Descending power layers are also observed during this period. A number of mechanisms are proposed to describe these observations.D. A. Holdsworth, R. A. Vincent, and I. M. Rei
Challenges in using GPUs for the real-time reconstruction of digital hologram images
This is the pre-print version of the final published paper that is available from the link below.In-line holography has recently made the transition from silver-halide based recording media, with laser reconstruction, to recording with large-area pixel detectors and computer-based reconstruction. This form of holographic imaging is an established technique for the study of fine particulates, such as cloud or fuel droplets, marine plankton and alluvial sediments, and enables a true 3D object field to be recorded at high resolution over a considerable depth.
The move to digital holography promises rapid, if not instantaneous, feedback as it avoids the need for the time-consuming chemical development of plates or film film and a dedicated replay system, but with the growing use of video-rate holographic recording, and the desire to reconstruct fully every frame, the computational challenge becomes considerable. To replay a digital hologram a 2D FFT must be calculated for every depth slice desired in the replayed image volume. A typical hologram of ~100 μm particles over a depth of a few hundred millimetres will require O(10^3) 2D FFT operations to be performed on a hologram of typically a few million pixels.
In this paper we discuss the technical challenges in converting our existing reconstruction code to make efficient use of NVIDIA CUDA-based GPU cards and show how near real-time video slice reconstruction can be obtained with holograms as large as 4096 by 4096 pixels. Our performance to date for a number of different NVIDIA GPU running under both Linux and Microsoft Windows is presented. The recent availability of GPU on portable computers is discussed and a new code for interactive replay of digital holograms is presented
Management consultancy’s role in delivering lasting [triple bottom line] benefits
Management consultants have become ubiquitous in helping improve organizational performance. This paper presents an investigation of the impact of their interventions on organizational sustainability and growth through the performance improvement work carried out for and with their clients. The paper presents the findings of a questionnaire survey of 440 respondents from 206 countries; 197 of respondents were Small and Medium Sized Enterprises (SMEs) and 243 from large organizations. There is a particular focus on knowledge transfer in terms of urgency and impact of the work with regard to the extent to which consulting interventions in SMEs, as well as large multinational corporations, embed long-term sustainability practices
Discovery of a Magnetic DZ White Dwarf with Zeeman-Split Lines of Heavy Elements
A spectroscopic survey of previously-unstudied Luyten Half Second proper
motion stars has resulted in the discoveries of two new cool magnetic white
dwarfs. One (LHS 2273) is a routine DA star, T= 6,500K, with Zeeman-split H
alpha and H beta, for which a simple model suggests a polar field strength of
18.5 MG viewed close to equator-on. However, the white dwarf LHS 2534 proves to
be the first magnetic DZ showing Zeeman-split Na I and Mg I components, as well
as Ca I and Ca II lines for which Zeeman components are blended. The Na I
splittings result in a mean surface field strength estimate of 1.92 MG. Apart
from the magnetic field, LHS 2534 is one of the most heavily-blanketed and
coolest DZ white dwarfs at T ~ 6,000K.Comment: 7 pages, Astrophysical Journal (Letters), in pres
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