859 research outputs found
Avoidability index for binary patterns with reversal
For every pattern over the alphabet , we specify the
least such that is -avoidable.Comment: 15 pages, 1 figur
MONEY ILLUSION, GORMAN AND LAU
Any demand equation satisfying Lauâs (1982) Fundamental Theorem of Exact Aggregation and 0° homogeneity in prices and income will have a Gorman (1981) functional form for each income term. This property does not depend on symmetry or adding up. The implications of this result are illustrated by an extensive example.Demand, exact aggregation, functional form, homogeneity
Les signes dâune appartenance multidimensionnelle
Les comportements et les discours, crĂ©ateurs dâentreprise, sâintĂšgrent dans les pratiques des diffĂ©rentes appartenances auxquelles adhĂšre chacun des acteurs. Tout est jugĂ© Ă lâaune des intĂ©rĂȘts des groupes dâappartenance autant quâĂ celui des intĂ©rĂȘts individuels. Il sâagit lĂ dâenjeux qui sont habituellement masquĂ©s par des arguments dits « objectifs » portant sur le changement lui-mĂȘme. Les auteurs proposent une grille dâobservation des signes qui tĂ©moignent des appartenances des acteurs dâun projet. Elle a Ă©tĂ© construite Ă partir dâune Ă©tude de cas, la production dâun plan de communication, impliquant une agence de publicitĂ©, une entreprise-cliente et un environnement Ă la fois concurrentiel et partenaire. Cette triade agence-client-environnement se retrouve dans la planification et la gestion de la plupart des projets.The actions and the speech-acts, which are the real organizing factors of any organization, can be used as signs of different loyalties entertained by the actors. The problem is, for the observer, to identify these loyalties which are hidden in the apparently objective arguments referring to the project at hand. The authors propose an observation grid built from a case study involving an agency, a client and a specific environment. This trio of actors is present in all phases of planning and managing a project. And the arguments, signs of their differing and converging loyalties, can be traced using also a trio of negociated portals
Face the Music and Glance: How Nonverbal Behaviour Aids Human Robot Relationships Based in Music
It is our hypothesis that improvised musical interaction will be able to provide the extended engagement often failing others during long term Human Robot Interaction (HRI) trials. Our previous work found that simply framing sessions with their drumming robot Mortimer as social interactions increased both social presence and engagement, two factors we feel are crucial to developing and maintaining a positive and meaningful relationship between human and robot. For this study we investigate the inclusion of the additional social modalities, namely head pose and facial expression, as nonverbal behaviour has been shown to be an important conveyor of information in both social and musical contexts. Following a 6 week experimental study using automatic behavioural metrics, results demonstrate those subjected to nonverbal behaviours not only spent more time voluntarily with the robot, but actually increased the time they spent as the trial progressed. Further, that they interrupted the robot less during social interactions and played for longer uninterrupted. Conversely, they also looked at the robot less in both musical and social contexts. We take these results as support for open ended musical activity providing a solid grounding for human robot relationships and the improvement of this by the inclusion of appropriate nonverbal behaviours
Imperfect Price Deflation in Production Systems
Numeraire prices that are measured with error create challenges for econometric estimation. A straightforward approach for a model with linear input demands, such as generated from a quadratic normalized profit function, is proposed where the numeraire price is measured with error. Numeraire measurement error is likely because expected output price is measured imperfectly by actual output price. An approach using generalized method of moments is developed to estimate such errors-in-variables systems that avoids use of extra-sample data or additional structural specifications. Monte-Carlo examination of small sample properties shows promise. Measurement error is statistically significant using aggregate U.S. agricultural data
The Generalized Second Law implies a Quantum Singularity Theorem
The generalized second law can be used to prove a singularity theorem, by
generalizing the notion of a trapped surface to quantum situations. Like
Penrose's original singularity theorem, it implies that spacetime is null
geodesically incomplete inside black holes, and to the past of spatially
infinite Friedmann--Robertson--Walker cosmologies. If space is finite instead,
the generalized second law requires that there only be a finite amount of
entropy producing processes in the past, unless there is a reversal of the
arrow of time. In asymptotically flat spacetime, the generalized second law
also rules out traversable wormholes, negative masses, and other forms of
faster-than-light travel between asymptotic regions, as well as closed timelike
curves. Furthermore it is impossible to form baby universes which eventually
become independent of the mother universe, or to restart inflation. Since the
semiclassical approximation is used only in regions with low curvature, it is
argued that the results may hold in full quantum gravity. An introductory
section describes the second law and its time-reverse, in ordinary and
generalized thermodynamics, using either the fine-grained or the coarse-grained
entropy. (The fine-grained version is used in all results except those relating
to the arrow of time.) A proof of the coarse-grained ordinary second law is
given.Comment: 46 pages, 8 figures. v2: discussion of global hyperbolicity revised
(4.1, 5.2), more comments on AdS. v3: major revisions including change of
title. v4: similar to published version, but with corrections to plan of
paper (1) and definition of global hyperbolicity (3.2). v5: fixed proof of
Thm. 1, changed wording of Thm. 3 & proof of Thm. 4, revised Sec. 5.2, new
footnote
Measurement of Spin Transfer Observables in Antiproton-Proton -> Antilambda-Lambda at 1.637 GeV/c
Spin transfer observables for the strangeness-production reaction
Antiproton-Proton -> Antilambda-Lambda have been measured by the PS185
collaboration using a transversely-polarized frozen-spin target with an
antiproton beam momentum of 1.637 GeV/c at the Low Energy Antiproton Ring at
CERN. This measurement investigates observables for which current models of the
reaction near threshold make significantly differing predictions. Those models
are in good agreement with existing measurements performed with unpolarized
particles in the initial state. Theoretical attention has focused on the fact
that these models produce conflicting predictions for the spin-transfer
observables D_{nn} and K_{nn}, which are measurable only with polarized target
or beam. Results presented here for D_{nn} and K_{nn} are found to be in
disagreement with predictions from existing models. These results also
underscore the importance of singlet-state production at backward angles, while
current models predict complete or near-complete triplet-state dominance.Comment: 5 pages, 3 figure
Born-Infeld Theory and Stringy Causality
Fluctuations around a non-trivial solution of Born-Infeld theory have a
limiting speed given not by the Einstein metric but the Boillat metric. The
Boillat metric is S-duality invariant and conformal to the open string metric.
It also governs the propagation of scalars and spinors in Born-Infeld theory.
We discuss the potential clash between causality determined by the closed
string and open string light cones and find that the latter never lie outside
the former. Both cones touch along the principal null directions of the
background Born-Infeld field. We consider black hole solutions in situations in
which the distinction between bulk and brane is not sharp such as space filling
branes and find that the location of the event horizon and the thermodynamic
properties do not depend on whether one uses the closed or open string metric.
Analogous statements hold in the more general context of non-linear
electrodynamics or effective quantum-corrected metrics. We show how Born-Infeld
action to second order might be obtained from higher-curvature gravity in
Kaluza-Klein theory. Finally we point out some intriguing analogies with
Einstein-Schr\"odinger theory.Comment: 31 pages, 4 figures, LaTex; Some comments and references adde
Self-dual gravity and self-dual Yang-Mills in the context of Macdowell-Mansouri formalism
In this work we propose an action which unifies self-dual gravity and
self-dual Yang-Mills in the context of the Macdowell-Mansouri formalism. We
claim that such an action may be used to find the S-dual action for both
self-dual gravity and self-dual Yang-Mills.Comment: 8 pages, Revtex, no figures, submitted to Phys. Rev.
Trends in Initial Lower Extremity Amputation Rates Among Veterans Health Administration Health Care System Users From 2000 to 2004
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