841 research outputs found
Community Response to Forestry Transition in Rural Canada: Analysis of Media and Census Data for Six Case Study Communities in New Brunswick and British Columbia
The forest economy is in transition across Canada. Faced with high dollar values, increasing competition within the global market, high input costs for energy, labour and fibre, and growing expectations for environmental performance, the forest sector is undergoing significant economic transitions as companies across the country cut costs, close mills and shed jobs. This report contributes to our understanding of community response to mill closure with a detailed description of six case study communities during a period of forest industry mill closures. Three communities are in British Columbia (Mackenzie, Quesnel and Fort St. James) and three communities are in New Brunswick (Dalhousie, Nackawic and Mirimachi). Empirical information is derived from national and local media reports as well as recent data from the Census of Canada. Key thematic areas include resilience, economic diversification, the nature of mill closure, union involvement, government involvement and concerns over government policy changes such as appurtenancy.media analysis, rural sociology, community development, rural development, social change, Community/Rural/Urban Development, R52, R58, Q33,
Social and Ethical Considerations of Nuclear Power Development
A new urgency is emerging around nuclear power development and this urgency is accentuated by the post-tsunami events at the Fukushima Daiichi nuclear power plant in Japan. This urgency extends beyond these dramatic events in Japan, however, to many other regions of the world and situations where nuclear power development is receiving renewed attention as an alternative to carbon-based energy sources. As a contribution to the growing public debate about nuclear power development, this paper offers a set of insights into the social and ethical aspects of nuclear power development by drawing from published literature in the humanities and social sciences. We offer insights into public risk perception of nuclear power at individual and national levels, the siting of nuclear waste repositories, the changing policy context for nuclear power development, social movements, and the challenges of risk management at the institutional level. We also pay special attention to the ethical aspects of nuclear power with attention to principles such as means and ends, use value and intrinsic value, private goods and public goods, harm, and equity considerations. Finally, we provide recommendations for institutional design and performance in nuclear power design and management.nuclear power, risk perception, social context, megaprojects, energy production, applied ethics, social values, social movements, complexity, hazards, disaster response, Environmental Economics and Policy, Resource /Energy Economics and Policy, Risk and Uncertainty, Q40, Z00,
Mimicking a Squeezed Bath Interaction: Quantum Reservoir Engineering with Atoms
The interaction of an atomic two-level system and a squeezed vacuum leads to
interesting novel effects in atomic dynamics, including line narrowing in
resonance fluorescence and absorption spectra, and a suppressed (enhanced)
decay of the in-phase and out-of phase component of the atomic polarization. On
the experimental side these predictions have so far eluded observation,
essentially due to the difficulty of embedding atoms in a 4 pi squeezed vacuum.
In this paper we show how to ``engineer'' a squeezed-bath-type interaction for
an effective two-level system. In the simplest example, our two-level atom is
represented by the two ground levels of an atom with angular momentum J=1/2 ->
J=1/2 transition (a four level system) which is driven by (weak) laser fields
and coupled to the vacuum reservoir of radiation modes. Interference between
the spontaneous emission channels in optical pumping leads to a squeezed bath
type coupling, and thus to symmetry breaking of decay on the Bloch sphere. With
this system it should be possible to observe the effects predicted in the
context of squeezed bath - atom interactions. The laser parameters allow one to
choose properties of the squeezed bath interaction, such as the (effective)
photon number expectation number N and the squeezing phase phi. We present
results of a detailed analytical and numerical study.Comment: 24 pages, 8 figure
Omnidirectional scattering of ultrasonic waves from rough surfaces of known statistics with application to electromagnetic scattering
Directional properties of ultrasonic waves scattered from rough surfaces with applications to electromagnetic scatterin
Robust creation of atomic W state in a cavity by adiabatic passage
We propose two robust schemes to generate controllable (deterministic) atomic
W-states of three three-level atoms interacting with an optical cavity and a
laser beam. Losses due to atomic spontaneous emissions and to cavity decay are
efficiently suppressed by employing adiabatic passage technique and
appropriately designed atom-field couplings. In these schemes the three atoms
traverse the cavity-mode and the laser beam and become entangled in the free
space outside the cavity.Comment: 7 pages, 6 figures. Submitted to Optics Communication
The influence of magnetic field geometry on magnetars X-ray spectra
Nowadays, the analysis of the X-ray spectra of magnetically powered neutron
stars or magnetars is one of the most valuable tools to gain insight into the
physical processes occurring in their interiors and magnetospheres. In
particular, the magnetospheric plasma leaves a strong imprint on the observed
X-ray spectrum by means of Compton up-scattering of the thermal radiation
coming from the star surface. Motivated by the increased quality of the
observational data, much theoretical work has been devoted to develop Monte
Carlo (MC) codes that incorporate the effects of resonant Compton scattering in
the modeling of radiative transfer of photons through the magnetosphere. The
two key ingredients in this simulations are the kinetic plasma properties and
the magnetic field (MF) configuration. The MF geometry is expected to be
complex, but up to now only mathematically simple solutions (self-similar
solutions) have been employed. In this work, we discuss the effects of new,
more realistic, MF geometries on synthetic spectra. We use new force-free
solutions in a previously developed MC code to assess the influence of MF
geometry on the emerging spectra. Our main result is that the shape of the
final spectrum is mostly sensitive to uncertain parameters of the
magnetospheric plasma, but the MF geometry plays an important role on the
angle-dependence of the spectra.Comment: 6 pages, 4 figures To appear in Proceedings of II Iberian Nuclear
Astrophysics Meeting held in Salamanca, September 22-23, 201
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Modulating stiffness with photo-switchable supramolecular hydrogels
Stimuli-responsive hydrogels are attractive materials with many applications towards biomedicine,biology, construction, and manufacturing. Materials that can be cured or annealed rapidly at room temperature are of particular interest. In this work we develop a class of supramolecular coumarin-functionalised hydrogels formedviahost-guest mediated self-assembly with cucurbit[8]uril thatcan photo-switch to covalent gels and reversibly toggle between the two states. A principle ad-vantage of such materials is their ability to maintain a homogeneous chemical composition and crosslink density while selectively modulating stiffness with light. An investigation of the photo-reversibility of these functional materials elucidated that hydroxyethyl cellulose-coumarin based gels were soft and could only switch from a physical state to a covalent one, while hyaluronic acid-coumarin based gels were softer and could be photo-reversed back into a physical state after covalent curing.A.T. acknowledges The Winston Churchill Foundation of the United States.
R.A.F. acknowledges the Cambridge Commonwealth European and International Trust.
C.C.P. acknowledges the Engineering and Physical Sciences Research Council.
G.W. acknowledges the Leverhulme Trus
Deterministic cavity quantum electrodynamics with trapped ions
We have employed radio-frequency trapping to localize a single 40Ca+-ion in a high-finesse optical cavity. By means of laser Doppler cooling, the position spread of the ion's wavefunction along the cavity axis was reduced to 42 nm, a fraction of the resonance wavelength of ionized calcium (λ = 397 nm). By controlling the position of the ion in the optical field, continuous and completely deterministic coupling of ion and field was realized. The precise three-dimensional location of the ion in the cavity was measured by observing the fluorescent light emitted upon excitation in the cavity field. The single-ion system is ideally suited to implement cavity quantum electrodynamics under cw conditions. To this end we operate the cavity on the D3/2–P1/2 transition of 40Ca+ (λ = 866 nm). Applications include the controlled generation of single-photon pulses with high efficiency and two-ion quantum gates
Does particle decay cause wave function collapse: An experimental test
We describe an experimental test of whether particle decay causes wave
function collapse. The test uses interference between two well separated, but
coherent, sources of vector mesons. The short-lived mesons decay before their
wave functions can overlap, so any interference must involve identical final
states. Unlike previous tests of nonlocality, the interference involves
continuous variables, momentum and position. Interference can only occur if the
wave function retains amplitudes for all possible decays. The interference can
be studied through the transverse momentum spectrum of the reconstructed
mesons.Comment: Slightly revised version, to appear in Phys. Lett. A. 11 pgs.,
including 2 figure
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