32,220 research outputs found
The LCO/Palomar 10,000 km/sec Cluster Survey. II. Constraints on Large-Scale Streaming
The LCO/Palomar 10,000 km/sec (LP10K) Tully-Fisher (TF) data set is used to
test for bulk streaming motions on a ~150 Mpc scale. The sample consists of 172
cluster galaxies in the original target range of the survey, 9000-13,000
km/sec, plus an additional 72 galaxies with cz < 30,000 km/sec. A
maximum-likelihood analysis that is insensitive to Malmquist and selection bias
effects is used to constrain the bulk velocity parameters, and realistic
Monte-Carlo simulations are carried out to correct residual biases and
determine statistical errors. When the analysis is restricted to the original
target range, the bias-corrected bulk flow is v_B=720 +/- 280 km/sec toward
l=266, b=19. When all objects out to z=0.1 are included the result is virtually
unchanged, v_B=700 +/- 250 km/sec toward l=272, b=10. The hypothesis that the
Hubble flow has converged to the CMB frame at distances less than ~ 100 Mpc is
ruled out at the 97% confidence level. The data are inconsistent with the flow
vector found by Lauer & Postman. However, the LP10K bulk flow is consistent
with that obtained from the SMAC survey of elliptical galaxies recently
described by Hudson et al. If correct, the LP10K results indicate that the
convergence depth for the Hubble flow is >~ 150 Mpc.Comment: 14 pages, 7 figures, uses emulateapj, submitted to the Astrophysical
Journal. Also available at http://astro.stanford.edu/jeff
Spectral universality of strong shocks accelerating charged particles
As a rule, the shock compression controls the spectrum of diffusively
accelerated particles. We argue that this is not so if the backreaction of
these particles on the shock structure is significant. We present a
self-similar solution in which the accelerated particles change the flow
structure near the shock so strongly that the total shock compression may
become arbitrarily large. Despite this, the energy spectrum behind the shock is
close to E^{-3/2} independently of anything at all.Comment: Submitted to ApJL, 4 pages, 1 figure, uses revtex and boxedep
Condensation risk – impact of improvements to Part L and robust details on Part C Final report: BD2414
This report summarises the main findings of the project ‘Impacts of Improvements to Part L and Robust Construction Details (RCD) on Part C’. The work consisted of a fieldwork element, undertaken by Leeds Metropolitan University and a modelling element carried out by University College London. Details of the work programme are contained in Appendix 1. The fieldwork consisted of the analysis of design material and site surveys from 16 housing developments constructed to Part L 2002 and adopting the Robust Construction Detail route to compliance. The modelling element of the project sought to identify the extent to which the ‘as built’ details give rise to a significantly increased condensation risk as compared to the relevant ‘standard’ robust construction details, as defined in the guidance. In addition to assessing ‘as built’ performance, the modelling phase of the project has investigated the suitability of the relevant calculation methods used to assess the risk of surface and interstitial condensation and mould growth. This report draws together the important conclusions from the project which has previously been presented in several very detailed interim reports and also for the first time presents the results of a workshop where these results were discussed to obtain industry feedback. The overall conclusions, future work and dissemination plans are also presented
An evaluation of the hygrothermal performance of 'standard' and 'as built' construction details using steadystate and transient modelling
Accurate assessment of both surface and interstitial condensation risk at the design stage of buildings is of great importance - not just to minimise the damaging effects moisture can cause to building envelopes, but also to contribute to the provision of adequate indoor air quality. Guidance certainly does exist with regards to limiting thermal bridging in order to prevent condensation occurring on new constructions. However, a recent study has provided clear evidence that the reality, both in translating the available guidance into a specific design and in construction on site is often rather different from the 'ideal'. This paper reports on that study and compares and evaluates the hygrothermal performance of construction details for different phases during the building life cycle. The results of both the surface and interstitial condensation risk simulations under both steady-state and transient conditions are presented and discussed. Significant differences in the hygrothermal performance of 'standard' and 'as built' construction details are observed
Quantum Correlation Bounds for Quantum Information Experiments Optimization: the Wigner Inequality Case
Violation of modified Wigner inequality by means binary bipartite quantum
system allows the discrimination between the quantum world and the classical
local-realistic one, and also ensures the security of Ekert-like quantum key
distribution protocol. In this paper we study both theoretically and
experimentally the bounds of quantum correlation associated to the modified
Wigner's inequality finding the optimal experimental configuration for its
maximal violation. We also extend this analysis to the implementation of
Ekert's protocol
Feasibility of loophole-free nonlocality tests with a single photon
Recently much interest has been directed towards designing setups that
achieve realistic loss thresholds for decisive tests of local realism, in
particular in the optical regime. We analyse the feasibility of such Bell tests
based on a W-state shared between multiple parties, which can be realised for
example by a single photon shared between spatial modes. We develop a general
error model to obtain thresholds on the efficiencies required to violate local
realism, and also consider two concrete optical measurement schemes.Comment: 8 pages, 5 figure
N-particle nonclassicality without N-particle correlations
Most of known multipartite Bell inequalities involve correlation functions
for all subsystems. They are useless for entangled states without such
correlations. We give a method of derivation of families of Bell inequalities
for N parties, which involve, e.g., only (N-1)-partite correlations, but still
are able to detect proper N-partite entanglement. We present an inequality
which reveals five-partite entanglement despite only four-partite correlations.
Classes of inequalities introduced here can be put into a handy form of a
single non-linear inequality. An example is given of an N qubit state, which
strongly violates such an inequality, despite having no N-qubit correlations.
This surprising property might be of potential value for quantum information
tasks.Comment: 5 page
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