5,459 research outputs found
Doing the opposite to what another person is doing.
The three studies presented here aim to contribute to a better understanding of the role of the coordinate system of a person's body and of the environment in spatial organization underlying the recognition and production of gestures. The paper introduces a new approach by investigating what people consider to be opposite gestures in addition to identical gestures.
It also suggests a new point of view setting the issue in the framework of egocentric versus allocentric spatial encoding as compared to the anatomical versus non-anatomical matching which is usually adopted in the literature.
The results showed that the role of the allocentric system as a key player was much more evident when participants were asked to \u201cdo the opposite\u201d as compared to when they imitated which indicates that the two tasks really are different from each other. Response times were also quicker when people \u201cdid the opposite\u201d indicating that this is an immediate response and not the result of \u201creversing an imitation\u201d. These findings suggest that the issue of how the oppositional structure of space impacts on human perception and the performance of gestures has probably been underestimated in an area of research which traditionally focuses exclusively on imitation
Resolution à la Kronheimer of C3/ Γ singularities and the Monge–Ampère equation for Ricci-flat Kähler metrics in view of D3-brane solutions of supergravity
In this paper, we analyze the relevance of the generalized Kronheimer construction for the gauge/gravity correspondence. We begin with the general structure of D3-brane solutions of type IIB supergravity on smooth manifolds YΓ that are supposed to be the crepant resolution of quotient singularities C3/ Γ with Γ a finite subgroup of SU(3). We emphasize that nontrivial 3-form fluxes require the existence of imaginary self-dual harmonic forms ω2 , 1. Although excluded in the classical Kronheimer construction, they may be reintroduced by means of mass deformations. Next we concentrate on the other essential item for the D3-brane construction, namely, the existence of a Ricci-flat metric on YΓ. We study the issue of Ricci-flat Kähler metrics on such resolutions YΓ, with particular attention to the case Γ = Z4. We advance the conjecture that on the exceptional divisor of YΓ the Kronheimer Kähler metric and the Ricci-flat one, that is locally flat at infinity, coincide. The conjecture is shown to be true in the case of the Ricci-flat metric on tot KWP[112] that we construct, i.e., the total space of the canonical bundle of the weighted projective space WP[112] , which is a partial resolution of C3/ Z4. For the full resolution, we have YZ4=totKF2, where F2 is the second Hirzebruch surface. We try to extend the proof of the conjecture to this case using the one-parameter Kähler metric on F2 produced by the Kronheimer construction as initial datum in a Monge–Ampère (MA) equation. We exhibit three formulations of this MA equation, one in terms of the Kähler potential, the other two in terms of the symplectic potential but with two different choices of the variables. In both cases, one can establish a series solution in powers of the variable along the fibers of the canonical bundle. The main property of the MA equation is that it does not impose any condition on the initial geometry of the exceptional divisor, rather it uniquely determines all the subsequent terms as local functionals of this initial datum. Although a formal proof is still missing, numerical and analytical results support the conjecture. As a by-product of our investigation, we have identified some new properties of this type of MA equations that we believe to be so far unknown
Marginal Deformations with U(1)^3 Global Symmetry
We generate new 11-dimensional supergravity solutions from deformations based
on U(1)^3 symmetries. The initial geometries are of the form AdS_4 x Y_7, where
Y_7 is a 7-dimensional Sasaki-Einstein space. We consider a general family of
cohomogeneity one Sasaki-Einstein spaces, as well as the recently-constructed
cohomogeneity three L^{p,q,r,s} spaces. For certain cases, such as when the
Sasaki-Einstein space is S^7, Q^{1,1,1} or M^{1,1,1}, the deformed gravity
solutions correspond to a marginal deformation of a known dual gauge theory.Comment: 28pp; Refs. added and to appear in JHE
Energy device for monitoring 4-10 MeV industrial electron accelerators
The electron beam energy is one of the critical parameters of electron accelerators since it can affect the dose distribution inside the body or in products to be irradiated with a beam of energetic electrons. A device has been developed for monitoring small variations in the electron beam energy that is easy-to-use during an irradiation run. It involves measurement of currents (or charges) collected by two identical aluminium plates, except for their thickness, and electrically insulated from each other, located in the beam. The ratio of these two currents (or collected charges) is quite sensitive to the beam energy; optimization of sensitivity is obtained by selecting the appropriate thickness of the front plate depending on the beam energy. In the present paper, we have investigated the feasibility of using this energy device at energies, from 4 to 10 MeV
Nominal Unification of Higher Order Expressions with Recursive Let
A sound and complete algorithm for nominal unification of higher-order
expressions with a recursive let is described, and shown to run in
non-deterministic polynomial time. We also explore specializations like nominal
letrec-matching for plain expressions and for DAGs and determine the complexity
of corresponding unification problems.Comment: Pre-proceedings paper presented at the 26th International Symposium
on Logic-Based Program Synthesis and Transformation (LOPSTR 2016), Edinburgh,
Scotland UK, 6-8 September 2016 (arXiv:1608.02534
Strings on conifolds from strong coupling dynamics: quantitative results
Three quantitative features of string theory on AdS_5 x X_5, for any
(quasi)regular Sasaki-Einstein X_5, are recovered exactly from an expansion of
field theory at strong coupling around configurations in the moduli space of
vacua. These configurations can be thought of as a generalized matrix model of
(local) commuting matrices. First, we reproduce the spectrum of scalar
Kaluza-Klein modes on X_5. Secondly, we recover the precise spectrum of BMN
string states, including a nontrivial dependence on the volume of X_5. Finally,
we show how the radial direction in global AdS_5 emerges universally in these
theories by exhibiting states dual to AdS giant gravitons.Comment: 1+28 pages. 1 figur
Spacetime singularity resolution by M-theory fivebranes: calibrated geometry, Anti-de Sitter solutions and special holonomy metrics
The supergravity description of various configurations of supersymmetric
M-fivebranes wrapped on calibrated cycles of special holonomy manifolds is
studied. The description is provided by solutions of eleven-dimensional
supergravity which interpolate smoothly between a special holonomy manifold and
an event horizon with Anti-de Sitter geometry. For known examples of Anti-de
Sitter solutions, the associated special holonomy metric is derived. One
explicit Anti-de Sitter solution of M-theory is so treated for fivebranes
wrapping each of the following cycles: K\"{a}hler cycles in Calabi-Yau two-,
three- and four-folds; special lagrangian cycles in three- and four-folds;
associative three- and co-associative four-cycles in manifolds; complex
lagrangian four-cycles in manifolds; and Cayley four-cycles in
manifolds. In each case, the associated special holonomy metric is
singular, and is a hyperbolic analogue of a known metric. The analogous known
metrics are respectively: Eguchi-Hanson, the resolved conifold and the
four-fold resolved conifold; the deformed conifold, and the Stenzel four-fold
metric; the Bryant-Salamon-Gibbons-Page-Pope metrics on an
bundle over , and an bundle over or ;
the Calabi hyper-K\"{a}hler metric on ; and the
Bryant-Salamon-Gibbons-Page-Pope metric on an bundle
over . By the AdS/CFT correspondence, a conformal field theory is
associated to each of the new singular special holonomy metrics, and defines
the quantum gravitational physics of the resolution of their singularities.Comment: 1+52 page
Holographic Renormalization of general dilaton-axion gravity
We consider a very general dilaton-axion system coupled to Einstein-Hilbert
gravity in arbitrary dimension and we carry out holographic renormalization for
any dimension up to and including five dimensions. This is achieved by
developing a new systematic algorithm for iteratively solving the radial
Hamilton-Jacobi equation in a derivative expansion. The boundary term derived
is valid not only for asymptotically AdS backgrounds, but also for more general
asymptotics, including non-conformal branes and Improved Holographic QCD. In
the second half of the paper, we apply the general result to Improved
Holographic QCD with arbitrary dilaton potential. In particular, we derive the
generalized Fefferman-Graham asymptotic expansions and provide a proof of the
holographic Ward identities.Comment: 42 pages. v2: two references added. Version published in JHEP. v3:
fixed minor typos in eqs. (1.6), (2.3), (3.20), (A.3), (B.8), (B.12) and
(B.22
Scenario planning for the Edinburgh city region
This paper examines the application of scenario planning techniques to the detailed and daunting challenge of city re-positioning when policy makers are faced with a heavy history and a complex future context. It reviews a process of scenario planning undertaken in the Edinburgh city region, exploring the scenario process and its contribution to strategies and policies for city repositioning. Strongly rooted in the recent literature on urban and regional economic development, the text outlines how key individuals and organisations involved in the process participated in far-reaching analyses of the possible future worlds in which the Edinburgh city region might find itself
Supersymmetric AdS_5 Solutions of Type IIB Supergravity
We analyse the most general bosonic supersymmetric solutions of type IIB
supergravity whose metrics are warped products of five-dimensional anti-de
Sitter space AdS_5 with a five-dimensional Riemannian manifold M_5. All fluxes
are allowed to be non-vanishing consistent with SO(4,2) symmetry. We show that
the necessary and sufficient conditions can be phrased in terms of a local
identity structure on M_5. For a special class, with constant dilaton and
vanishing axion, we reduce the problem to solving a second order non-linear
ODE. We find an exact solution of the ODE which reproduces a solution first
found by Pilch and Warner. A numerical analysis of the ODE reveals an
additional class of local solutions.Comment: 33 page
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