22,879 research outputs found
Mediapolis: an introduction
The organisation of this workshop has been prompted by concerns with the way media so
often seem to get left out of writing on cities and urban politics (rather than vice-versa).
We agree with Iveson’s (2007) argument that urban and media studies have much more
in the way of shared concerns when it comes to politics than is conventionally thought to
be the case. As a result, we are hoping this workshop will create an occasion for urban
scholars to meet those studying media, to explore what difference it makes to explicitly
consider the place of media practices in making a politics of cities, and conversely, to
consider what is left out when such practices are relegated to the background. In certain
ways, we are suggesting a contemporary return to something like Robert Park’s
inclination in relation to cities and media. In his seminal essay on the natural history of
the newspaper, for example (Park, 1925), Park exhibits a style which does not generally
seem to distinguish between or oppose the urban and the media when studying politics
and democracy. This surely has something to do with Park’s own intellectual period, and
the absence of established disciplines in media or urban studies. Yet this is also precisely
the point of the workshop: an opportunity for engagement and discussion through a
similar sort of pre-disciplinary spirit
Difficulty of distinguishing product states locally
Non-locality without entanglement is a rather counter-intuitive phenomenon in
which information may be encoded entirely in product (unentangled) states of
composite quantum systems in such a way that local measurement of the
subsystems is not enough for optimal decoding. For simple examples of pure
product states, the gap in performance is known to be rather small when
arbitrary local strategies are allowed. Here we restrict to local strategies
readily achievable with current technology; those requiring neither a quantum
memory nor joint operations. We show that, even for measurements on pure
product states there can be a large gap between such strategies and
theoretically optimal performance. Thus even in the absence of entanglement
physically realizable local strategies can be far from optimal for extracting
quantum information.Comment: 5 pages, 1 figur
Optimal minimum-cost quantum measurements for imperfect detection
Knowledge of optimal quantum measurements is important for a wide range of
situations, including quantum communication and quantum metrology. Quantum
measurements are usually optimised with an ideal experimental realisation in
mind. Real devices and detectors are, however, imperfect. This has to be taken
into account when optimising quantum measurements. In this paper, we derive the
optimal minimum-cost and minimum-error measurements for a general model of
imperfect detection.Comment: 5 page
N/P GaAs concentrator solar cells with an improved grid and bushbar contact design
The major requirements for a solar cell used in space applications are high efficiency at AMO irradiance and resistance to high energy radiation. Gallium arsenide, with a band gap of 1.43 eV, is one of the most efficient sunlight to electricity converters (25%) when the the simple diode model is used to calculate efficiencies at AMO irradiance, GaAs solar cells are more radiation resistant than silicon solar cells and the N/P GaAs device has been reported to be more radiation resistant than similar P/N solar cells. This higher resistance is probably due to the fact that only 37% of the current is generated in the top N layer of the N/P cell compared to 69% in the top layer of a P/N solar cell. This top layer of the cell is most affected by radiation. It has also been theoretically calculated that the optimized N/P device will prove to have a higher efficiency than a similar P/N device. The use of a GaP window layer on a GaAs solar cell will avoid many of the inherent problems normally associated with a GaAlAs window while still proving good passivation of the GaAs surface. An optimized circular grid design for solar cell concentrators has been shown which incorporates a multi-layer metallization scheme. This multi-layer design allows for a greater current carrying capacity for a unit area of shading, which results in a better output efficiency
Discrimination of two mixed quantum states with maximum confidence and minimum probability of inconclusive results
We study an optimized measurement that discriminates two mixed quantum states
with maximum confidence for each conclusive result, thereby keeping the overall
probability of inconclusive results as small as possible. When the rank of the
detection operators associated with the two different conclusive outcomes does
not exceed unity we obtain a general solution. As an application, we consider
the discrimination of two mixed qubit states. Moreover, for the case of
higher-rank detection operators we give a solution for particular states. The
relation of the optimized measurement to other discrimination schemes is also
discussed.Comment: 7 pages, 1 figure, accepted for publication in Phys. Rev.
Epac and the high affinity rolipram binding conformer of PDE4 modulate neurite outgrowth and myelination using an in vitro spinal cord injury model
<b>Background and Purpose</b><p></p>
cAMP and pharmacological inhibition of PDE4, which degrades it, are promising therapeutic targets for the treatment of spinal cord injury (SCI). Using our previously described in vitro SCI model, we studied the mechanisms by which cAMP modulators promote neurite outgrowth and myelination using enantiomers of the PDE4-specific inhibitor rolipram and other modulators of downstream signalling effectors.<p></p>
<b>Experimental Approach</b><p></p>
Rat mixed neural cell myelinating cultures were cut with a scalpel and treated with enantiomers of the PDE4-specific inhibitor rolipram, Epac agonists and PKA antagonists. Neurite outgrowth, density and myelination were assessed by immunocytochemistry and cytokine levels analysed by qPCR.<p></p>
<b>Key Results</b><p></p>
Inhibition of the high-affinity rolipram-binding state (HARBS), rather than the low-affinity rolipram binding state (LARBS) PDE4 conformer promoted neurite outgrowth and myelination. These effects were mediated through the activation of Epac and not through PKA. Expression of the chemokine CXCL10, known to inhibit myelination, was markedly elevated in astrocytes after Rho inhibition and this was blocked by inhibition of Rho kinase or PDE4.<p></p>
<b>Conclusions and Implications</b><p></p>
PDE4 inhibitors targeted at the HARBS conformer or Epac agonists may provide promising novel targets for the treatment of SCI. Our study demonstrates the differential mechanisms of action of these compounds, as well as the benefit of a combined pharmacological approach and highlighting potential promising targets for the treatment of SCI. These findings need to be confirmed in vivo
Arkansas Cotton Variety Test 2016
The primary goal of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas
Maximum Confidence Quantum Measurements
We consider the problem of discriminating between states of a specified set
with maximum confidence. For a set of linearly independent states unambiguous
discrimination is possible if we allow for the possibility of an inconclusive
result. For linearly dependent sets an analogous measurement is one which
allows us to be as confident as possible that when a given state is identified
on the basis of the measurement result, it is indeed the correct state.Comment: 4 pages, 2 figure
Space-time variation of malaria incidence in Yunnan province, China
BACKGROUND Understanding spatio-temporal variation in malaria incidence provides a basis for effective disease control planning and monitoring. METHODS Monthly surveillance data between 1991 and 2006 for Plasmodium vivax and Plasmodium falciparum malaria across 128 counties were assembled for Yunnan, a province of China with one of the highest burdens of malaria. County-level Bayesian Poisson regression models of incidence were constructed, with effects for rainfall, maximum temperature and temporal trend. The model also allowed for spatial variation in county-level incidence and temporal trend, and dependence between incidence in June-September and the preceding January-February. RESULTS Models revealed strong associations between malaria incidence and both rainfall and maximum temperature. There was a significant association between incidence in June-September and the preceding January-February. Raw standardised morbidity ratios showed a high incidence in some counties bordering Myanmar, Laos and Vietnam, and counties in the Red River valley. Clusters of counties in south-western and northern Yunnan were identified that had high incidence not explained by climate. The overall trend in incidence decreased, but there was significant variation between counties. CONCLUSION Dependence between incidence in summer and the preceding January-February suggests a role of intrinsic host-pathogen dynamics. Incidence during the summer peak might be predictable based on incidence in January-February, facilitating malaria control planning, scaled months in advance to the magnitude of the summer malaria burden. Heterogeneities in county-level temporal trends suggest that reductions in the burden of malaria have been unevenly distributed throughout the province.This project was supported by a University of Queensland New Research Scientist Start-Up Fund grant. RWS is a Wellcome Trust Principal Research Fellow (#079080) and receives additional support from the Wellcome Trust for the Malaria Atlas Project (MAP, http://www.map.ox.ac.uk)
Enhancing space transportation: The NASA program to develop electric propulsion
The NASA Office of Aeronautics, Exploration, and Technology (OAET) supports a research and technology (R and T) program in electric propulsion to provide the basis for increased performance and life of electric thruster systems which can have a major impact on space system performance, including orbital transfer, stationkeeping, and planetary exploration. The program is oriented toward providing high-performance options that will be applicable to a broad range of near-term and far-term missions and vehicles. The program, which is being conducted through the Jet Propulsion Laboratory (JPL) and Lewis Research Center (LeRC) includes research on resistojet, arcjets, ion engines, magnetoplasmadynamic (MPD) thrusters, and electrodeless thrusters. Planning is also under way for nuclear electric propulsion (NEP) as part of the Space Exploration Initiative (SEI)
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