793 research outputs found
OPE statistics from higher-point crossing
We present new asymptotic formulas for the distribution of OPE coefficients in conformal field theories. These formulas involve products of four or more coefficients and include light-light-heavy as well as heavy-heavy-heavy contributions. They are derived from crossing symmetry of the six and higher point functions on the plane and should be interpreted as non-Gaussianities in the statistical distribution of the OPE coefficients. We begin with a formula for arbitrary operator exchanges (not necessarily primary) valid in any dimension. This is the first asymptotic formula constraining heavy-heavy-heavy OPE coefficients in d > 2. For two-dimensional CFTs, we present refined asymptotic formulas stemming from exchanges of quasi-primaries as well as Virasoro primaries.We present new asymptotic formulas for the distribution of OPE coefficients in conformal field theories. These formulas involve products of four or more coefficients and include light-light-heavy as well as heavy-heavy-heavy contributions. They are derived from crossing symmetry of the six and higher point functions on the plane and should be interpreted as non-Gaussianities in the statistical distribution of the OPE coefficients. We begin with a formula for arbitrary operator exchanges (not necessarily primary) valid in any dimension. This is the first asymptotic formula constraining heavy-heavy-heavy OPE coefficients in . For two-dimensional CFTs, we present refined asymptotic formulas stemming from exchanges of quasi-primaries as well as Virasoro primaries
Happiness, environmental protection and market economy
The manufacturing sector is leaving the West for Asiaâs low wages and good working culture. Europe would be better off keeping these manufacturing activities, slowing down wage inflation and what is more, letting a young, cheaper workforce from the East settle down within their borders. This would aid in preserving the diverse economic structure which has been characteristic for Europe.Beside the economic growth there are two more concepts which have turned into the âholy cowsâ of economics during the last fifty years. One is the need to constantly improve labor productivity and the other is increasing competitiveness of nations. The high labor productivity of some countries, induces severe unemployment in the globalized world. In the other hand it is high time we understood that it is not competition, but cooperation that brings more happiness to humanity.Should we still opt for âhappinessâ and âsanityâ, it is quite obvious that we all should, in economistsâ terms, define our individual welfare functions corresponding to our own set of values, staying free from the influence of media, advertisements and fashion. The cornerstone to all this is the intelligent citizen who prefers local goods and services
Discovery of Five New Pulsars in Archival Data
Reprocessing of the Parkes Multibeam Pulsar Survey has resulted in the
discovery of five previously unknown pulsars and several as-yet-unconfirmed
candidates. PSR J0922-52 has a period of 9.68 ms and a DM of 122.4 pc cm^-3.
PSR J1147-66 has a period of 3.72 ms and a DM of 133.8 pc cm^-3. PSR J1227-6208
has a period of 34.53 ms, a DM of 362.6 pc cm^-3, is in a 6.7 day binary orbit,
and was independently detected in an ongoing high-resolution Parkes survey by
Thornton et al. and also in independent processing by Einstein@Home volunteers.
PSR J1546-59 has a period of 7.80 ms and a DM of 168.3 pc cm^-3. PSR J1725-3853
is an isolated 4.79-ms pulsar with a DM of 158.2 pc cm^-3. These pulsars were
likely missed in earlier processing efforts due to their high DMs and short
periods and the large number of candidates that needed to be looked through.
These discoveries suggest that further pulsars are awaiting discovery in the
multibeam survey data.Comment: 12 pages, 2 figures, 2 tables, accepted to Ap
Application of Compromise Programming to a semi-detached housing development in order to balance economic and environmental criteria
This is a post-peer-review, pre-copyedit version of an article published in Journal of the Operational Research Society. The definitive publisher-authenticated version: RuĂĄ Aguilar, MJ.; Guadalajara Olmeda, MN. (2012). Application of Compromise Programming to a semi-detached housing development in order to balance economic and environmental criteria. Journal of the Operational Research Society. 64(3):459-468, is available online at: http://www.palgrave-journals.com/jors/journal/v64/n3/full/jors201276a.html.European Energy Performance of Buildings Directives DE promote energy efficiency in buildings. Under these Directives, the European Union States must apply minimum requirements regarding the energy performance of buildings and ensure the certification of their energy performance. The Directives set only the basic principles and requirements, leaving a significant amount of room for the Member States to establish their specific mechanisms, numeric requirements and ways to implement them, taking into account local conditions. With respect to the Spanish case, the search for buildings that are more energy efficient results in a conflict between usersÂż economic objectives and society's environmental objectives. In this paper, Compromise Programming is applied to help in the decision-making process. An appropriate distribution of types of dwellings, according to their energy performance and to the climatic zone considered in Spain, will be suggested. Results provide a compromise solution between both objectives.RuĂĄ Aguilar, MJ.; Guadalajara Olmeda, MN. (2012). Application of Compromise Programming to a semi-detached housing development in order to balance economic and environmental criteria. Journal of the Operational Research Society. 64(3):459-468. doi:10.1057/jors.2012.76S459468643Andaloro, A. P. F., Salomone, R., Ioppolo, G., & Andaloro, L. (2010). Energy certification of buildings: A comparative analysis of progress towards implementation in European countries. Energy Policy, 38(10), 5840-5866. doi:10.1016/j.enpol.2010.05.039AndrĂ©, F. J., Cardenete, M. A., & Romero, C. (2008). Using compromise programming for macroeconomic policy making in a general equilibrium framework: theory and application to the Spanish economy. Journal of the Operational Research Society, 59(7), 875-883. doi:10.1057/palgrave.jors.2602415Baja, S., Chapman, D. M., & Dragovich, D. (2006). Spatial based compromise programming for multiple criteria decision making in land use planning. Environmental Modeling & Assessment, 12(3), 171-184. doi:10.1007/s10666-006-9059-1Ballestero, E., & Romero, C. (1991). A theorem connecting utility function optimization and compromise programming. Operations Research Letters, 10(7), 421-427. doi:10.1016/0167-6377(91)90045-qBallestero, E., & Romero, C. (1993). Weighting in compromise programming: A theorem on shadow prices. Operations Research Letters, 13(5), 325-329. doi:10.1016/0167-6377(93)90055-lDavies, H., & Wyatt, D. (2004). Appropriate use of the ISO 15686-1 factor method for durability and service life prediction. Building Research & Information, 32(6), 552-553. doi:10.1080/0961321042000291938Diakaki, C., Grigoroudis, E., Kabelis, N., Kolokotsa, D., Kalaitzakis, K., & Stavrakakis, G. (2010). A multi-objective decision model for the improvement of energy efficiency in buildings. Energy, 35(12), 5483-5496. doi:10.1016/j.energy.2010.05.012DıÌaz-Balteiro, L., & Romero, C. (2003). Forest management optimisation models when carbon captured is considered: a goal programming approach. Forest Ecology and Management, 174(1-3), 447-457. doi:10.1016/s0378-1127(02)00075-0Diaz-Balteiro, L., & Rodriguez, L. C. E. (2006). Optimal rotations on Eucalyptus plantations including carbon sequestrationâA comparison of results in Brazil and Spain. Forest Ecology and Management, 229(1-3), 247-258. doi:10.1016/j.foreco.2006.04.005Fattahi, P., & Fayyaz, S. (2009). A Compromise Programming Model to Integrated Urban Water Management. Water Resources Management, 24(6), 1211-1227. doi:10.1007/s11269-009-9492-4Hamdy, M., Hasan, A., & Siren, K. (2011). Applying a multi-objective optimization approach for Design of low-emission cost-effective dwellings. Building and Environment, 46(1), 109-123. doi:10.1016/j.buildenv.2010.07.006Johnstone, I. M. (2001). Energy and mass flows of housing: a model and example. Building and Environment, 36(1), 27-41. doi:10.1016/s0360-1323(99)00065-7Johnstone, I. M. (2001). Energy and mass flows of housing: estimating mortality. Building and Environment, 36(1), 43-51. doi:10.1016/s0360-1323(99)00066-9Linares, P., & Romero, C. (2000). A multiple criteria decision making approach for electricity planning in Spain: economic versus environmental objectives. Journal of the Operational Research Society, 51(6), 736-743. doi:10.1057/palgrave.jors.2600944Rey, F. J., Velasco, E., & Varela, F. (2007). Building Energy Analysis (BEA): A methodology to assess building energy labelling. Energy and Buildings, 39(6), 709-716. doi:10.1016/j.enbuild.2006.07.009Rudbeck, C. (2002). Service life of building envelope components: making it operational in economical assessment. Construction and Building Materials, 16(2), 83-89. doi:10.1016/s0950-0618(02)00003-xSan-JosĂ©, J. T., Losada, R., Cuadrado, J., & Garrucho, I. (2007). Approach to the quantification of the sustainable value in industrial buildings. Building and Environment, 42(11), 3916-3923. doi:10.1016/j.buildenv.2006.11.013Yu, P. L. (1973). A Class of Solutions for Group Decision Problems. Management Science, 19(8), 936-946. doi:10.1287/mnsc.19.8.936Zelany, M. (1974). A concept of compromise solutions and the method of the displaced ideal. Computers & Operations Research, 1(3-4), 479-496. doi:10.1016/0305-0548(74)90064-
The influence of residential and workday population mobility on exposure to air pollution in the UK
Traditional approaches of quantifying population-level exposure to air pollution assume that concentrations of air pollutants at the residential address of the study population are representative for overall exposure. This introduces potential bias in the quantification of human health effects. Our study combines new UK Census data comprising information on workday population densities, with high spatio-temporal resolution air pollution concentration fields from the WRF-EMEP4UK atmospheric chemistry transport model, to derive more realistic estimates of population exposure to NO2, PM2.5 and O3. We explicitly allocated workday exposures for weekdays between 8:00âŻam and 6:00âŻpm. Our analyses covered all of the UK at 1âŻkm spatial resolution. Taking workday location into account had the most pronounced impact on potential exposure to NO2, with an estimated 0.3âŻÎŒgâŻmâ3 (equivalent to 2%) increase in population-weighted annual exposure to NO2 across the whole UK population. Population-weighted exposure to PM2.5 and O3 increased and decreased by 0.3%, respectively, reflecting the different atmospheric processes contributing to the spatio-temporal distributions of these pollutants. We also illustrate how our modelling approach can be utilised to quantify individual-level exposure variations due to modelled time-activity patterns for a number of virtual individuals living and working in different locations in three example cities. Changes in annual-mean estimates of NO2 exposure for these individuals were considerably higher than for the total UK population average when including their workday location. Conducting model-based evaluations as described here may contribute to improving representativeness in studies that use small, portable, automatic sensors to estimate personal exposure to air pollution
Corresponding States of Structural Glass Formers
The variation with respect to temperature T of transport properties of 58
fragile structural glass forming liquids (68 data sets in total) are analyzed
and shown to exhibit a remarkable degree of universality. In particular,
super-Arrhenius behaviors of all super-cooled liquids appear to collapse to one
parabola for which there is no singular behavior at any finite temperature.
This behavior is bounded by an onset temperature To above which liquid
transport has a much weaker temperature dependence. A similar collapse is also
demonstrated, over the smaller available range, for existing numerical
simulation data.Comment: 6 pages, 2 figures. Updated References, Table Values, Submitted for
Publicatio
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High-radiation zone design of the FMIT high-density beam transport
The Fusion Materials Irradiation Test (FMIT) deuteron linac, operating at 35 MeV and 100 mA continuous duty, is expected to spill 3 ..mu..A/m and to lose 10 ..mu..A at specific bending-magnet positions. The major impact of this spill will be felt in the High-Energy Beam Transport (HEBT), where many beam-line components must be maintained. A modular design concept, that uses segmented termination panels remotely located from the modules, is being employed. Radiation-hardened quadrupoles can be opened, clam-shell fashion, to release the water-cooled beam tube r replacement if there is beam damage or lithium contamination from the target. Termination panels contain electrical, water, and instrumentation fittings to service the module, and are positioned to allow room for neutron-absorbing shielding between the beamline and the panel. The modular construction allows laboratory prealignment and check-out of all components on a structural carriage and is adaptable to supporting gamma shields. Proper choice of beam tube materials is essential for controlling activation caused by beam spill
Multi-Dimensional, Compressible Viscous Flow on a Moving Voronoi Mesh
Numerous formulations of finite volume schemes for the Euler and
Navier-Stokes equations exist, but in the majority of cases they have been
developed for structured and stationary meshes. In many applications, more
flexible mesh geometries that can dynamically adjust to the problem at hand and
move with the flow in a (quasi) Lagrangian fashion would, however, be highly
desirable, as this can allow a significant reduction of advection errors and an
accurate realization of curved and moving boundary conditions. Here we describe
a novel formulation of viscous continuum hydrodynamics that solves the
equations of motion on a Voronoi mesh created by a set of mesh-generating
points. The points can move in an arbitrary manner, but the most natural motion
is that given by the fluid velocity itself, such that the mesh dynamically
adjusts to the flow. Owing to the mathematical properties of the Voronoi
tessellation, pathological mesh-twisting effects are avoided. Our
implementation considers the full Navier-Stokes equations and has been realized
in the AREPO code both in 2D and 3D. We propose a new approach to compute
accurate viscous fluxes for a dynamic Voronoi mesh, and use this to formulate a
finite volume solver of the Navier-Stokes equations. Through a number of test
problems, including circular Couette flow and flow past a cylindrical obstacle,
we show that our new scheme combines good accuracy with geometric flexibility,
and hence promises to be competitive with other highly refined Eulerian
methods. This will in particular allow astrophysical applications of the AREPO
code where physical viscosity is important, such as in the hot plasma in galaxy
clusters, or for viscous accretion disk models.Comment: 26 pages, 21 figures. Submitted to MNRA
Singing the same tune? International continuities and discontinuities in how police talk about using force
This article focuses on a research project conducted in six jurisdictions: England, The Netherlands, Germany, Australia, Venezuela, and Brazil. These societies are very different ethnically, socially, politically, economically, historically and have wildly different levels of crime. Their policing arrangements also differ significantly: how they are organised; how their officers are equipped and trained; what routine operating procedures they employ; whether they are armed; and much else besides. Most relevant for this research, they represent policing systems with wildly different levels of police shootings, Police in the two Latin American countries represented here have a justified reputation for the frequency with which they shoot people, whereas at the other extreme the police in England do not routinely carry firearms and rarely shoot anyone. To probe whether these differences are reflected in the way that officers talk about the use of force, police officers in these different jurisdictions were invited to discuss in focus groups a scenario in which police are thwarted in their attempt to arrest two youths (one of whom is a known local criminal) by the youths driving off with the police in pursuit, and concludes with the youths crashing their car and escaping in apparent possession of a gun, It might be expected that focus groups would prove starkly different, and indeed they were, but not in the way that might be expected. There was little difference in affirmation of normative and legal standards regarding the use of force. It was in how officers in different jurisdictions envisaged the circumstances in which the scenario took place that led Latin American officers to anticipate that they would shoot the suspects, whereas officers in the other jurisdictions had little expectation that they would open fire in the conditions as they imagined them to be
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