2,697 research outputs found
Vacation laws and annual work hours
This article reviews the theory and evidence regarding how work hours are determined and the role of employer policies on vacation. The authors discuss possible economic rationales for vacation laws and present empirical evidence on whether they affect annual work hours. The results indicate that vacation laws lead to a substantial reduction in work hours.Hours of labor ; Vacations, Employee
Noise-free high-efficiency photon-number-resolving detectors
High-efficiency optical detectors that can determine the number of photons in
a pulse of monochromatic light have applications in a variety of physics
studies, including post-selection-based entanglement protocols for linear
optics quantum computing and experiments that simultaneously close the
detection and communication loopholes of Bell's inequalities. Here we report on
our demonstration of fiber-coupled, noise-free, photon-number-resolving
transition-edge sensors with 88% efficiency at 1550 nm. The efficiency of these
sensors could be made even higher at any wavelength in the visible and
near-infrared spectrum without resulting in a higher dark-count rate or
degraded photon-number resolution.Comment: 4 pages, 4 figures Published in Physical Review A, Rapid
Communications, 17 June 200
Weyl Quantization of Fractional Derivatives
The quantum analogs of the derivatives with respect to coordinates q_k and
momenta p_k are commutators with operators P_k and $Q_k. We consider quantum
analogs of fractional Riemann-Liouville and Liouville derivatives. To obtain
the quantum analogs of fractional Riemann-Liouville derivatives, which are
defined on a finite interval of the real axis, we use a representation of these
derivatives for analytic functions. To define a quantum analog of the
fractional Liouville derivative, which is defined on the real axis, we can use
the representation of the Weyl quantization by the Fourier transformation.Comment: 9 pages, LaTe
Science for development : the experience of the International Development Research Centre (IDRC)
Meeting: Science and Technology for the Eight Billion People of the Planet by 2020, 3-5 June 1993, Wiesbaden, DEIncludes "Empowerment through knowledge : the strategy of IDRC
Dynamics of Fractal Solids
We describe the fractal solid by a special continuous medium model. We
propose to describe the fractal solid by a fractional continuous model, where
all characteristics and fields are defined everywhere in the volume but they
follow some generalized equations which are derived by using integrals of
fractional order. The order of fractional integral can be equal to the fractal
mass dimension of the solid. Fractional integrals are considered as an
approximation of integrals on fractals. We suggest the approach to compute the
moments of inertia for fractal solids. The dynamics of fractal solids are
described by the usual Euler's equations. The possible experimental test of the
continuous medium model for fractal solids is considered.Comment: 12 pages, LaTe
Pastures from Space - Application of Satellite-Derived Pasture Predictions Improve the Profitability of Australian Sheep Producers
Pastures from Space, a collaborative program between CSIRO Livestock Industries and the Western Australian state Departments of Agriculture and Land Information, has developed the capacity to measure both the biomass and growth rate of annual pasture in the winter rainfall regions of southern Australia using satellite images (Edirisinghe et al., 2002). Producer groups were set up to pilot test the delivery of satellitederived pasture growth rate (PGR, kg dry matter/hectare.day) and biomass (feed on offer or FOO, kg dry matter/hectare) predictions for paddocks on individual farms in Western Australia. This paper reports on the value to Australian sheep producers of satellite-derived PGR information on pastures
Fractional derivatives of random walks: Time series with long-time memory
We review statistical properties of models generated by the application of a
(positive and negative order) fractional derivative operator to a standard
random walk and show that the resulting stochastic walks display
slowly-decaying autocorrelation functions. The relation between these
correlated walks and the well-known fractionally integrated autoregressive
(FIGARCH) models, commonly used in econometric studies, is discussed. The
application of correlated random walks to simulate empirical financial times
series is considered and compared with the predictions from FIGARCH and the
simpler FIARCH processes. A comparison with empirical data is performed.Comment: 10 pages, 14 figure
Squeezed States and Hermite polynomials in a Complex Variable
Following the lines of the recent paper of J.-P. Gazeau and F. H. Szafraniec
[J. Phys. A: Math. Theor. 44, 495201 (2011)], we construct here three types of
coherent states, related to the Hermite polynomials in a complex variable which
are orthogonal with respect to a non-rotationally invariant measure. We
investigate relations between these coherent states and obtain the relationship
between them and the squeezed states of quantum optics. We also obtain a second
realization of the canonical coherent states in the Bargmann space of analytic
functions, in terms of a squeezed basis. All this is done in the flavor of the
classical approach of V. Bargmann [Commun. Pur. Appl. Math. 14, 187 (1961)].Comment: 15 page
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