7,464 research outputs found
Ecological psychology is radical enough: A reply to radical enactivists
Ecological psychology is one of the most influential theories of perception in the embodied, anti-representational, and situated cognitive sciences. However, radical enactivists claim that Gibsonians tend to describe ecological information and its âpick upâ in ways that make ecological psychology close to representational theories of perception and cognition. Motivated by worries about the tenability of classical views of informational content and its processing, these authors claim that ecological psychology needs to be âRECtifiedâ so as to explicitly resist representational readings. In this paper, we argue against this call for RECtification. To do so, we offer a detailed analysis of the notion of perceptual information and other related notions such as specificity and meaning, as they are presented in the specialized ecological literature. We defend that these notions, if properly understood, remain free of any representational commitment. Ecological psychology, we conclude, does not need to be RECtified
On the Curvature Invariants of the Massive Banados-Teitelboim-Zanelli Black Holes and Their Holographic Pictures
In this paper, the curvature structure of a (2+1)-dimensional black hole in
the massive-charged-Born-Infeld gravity is investigated. The metric that we
consider is characterized by four degrees of freedom which are the mass and
electric charge of the black hole, the mass of the graviton field, and a
cosmological constant. For the charged and neutral cases separately, we present
various constraints among scalar polynomial curvature invariants which could
invariantly characterize our desired spacetimes. Specially, an appropriate
scalar polynomial curvature invariant and a Cartan curvature invariant which
together could detect the black hole horizon would be explicitly constructed.
Using algorithms related to the focusing properties of a bundle of light rays
on the horizon which are accounted by the Raychaudhuri equation, a procedure
for isolating the black hole parameters, as the algebraic combinations
involving the curvature invariants, would be presented. It will be shown that
this technique could specially be applied for black holes with zero electric
charge, contrary to the cases of solutions of lower-dimensional non-massive
gravity. In addition, for the case of massive (2+1)-dimensional black hole, the
irreducible mass, which quantifies the maximum amount of energy which could be
extracted from a black hole through the Penrose process would be derived.
Therefore, we show that the Hawking temperatures of these black holes could be
reduced to the pure curvature properties of the spacetimes. Finally, we comment
on the relationship between our analysis and the novel roles it could play in
numerical quark-gluon plasma simulations and other QCD models and also black
hole information paradox where the holographic correspondence could be
exploited.Comment: v3; 25 pages; 11 figures; 105 reference
Seeing spin dynamics in atomic gases
The dynamics of internal spin, electronic orbital, and nuclear motion states
of atoms and molecules have preoccupied the atomic and molecular physics
community for decades. Increasingly, such dynamics are being examined within
many-body systems composed of atomic and molecular gases. Our findings
sometimes bear close relation to phenomena observed in condensed-matter
systems, while on other occasions they represent truly new areas of
investigation. I discuss several examples of spin dynamics that occur within
spinor Bose-Einstein gases, highlighting the advantages of spin-sensitive
imaging for understanding and utilizing such dynamics.Comment: Chapter in upcoming Review Volume entitled "From Atomic to Mesoscale:
The Role of Quantum Coherence in Systems of Various Complexities" from World
Scientifi
Image processing for plastic surgery planning
This thesis presents some image processing tools for plastic surgery planning. In particular,
it presents a novel method that combines local and global context in a probabilistic
relaxation framework to identify cephalometric landmarks used in Maxillofacial plastic
surgery. It also uses a method that utilises global and local symmetry to identify abnormalities
in CT frontal images of the human body. The proposed methodologies are
evaluated with the help of several clinical data supplied by collaborating plastic surgeons
Matched detectors as definers of force
Although quantum states nicely express interference effects, outcomes of
experimental trials show no states directly; they indicate properties of
probability distributions for outcomes. We prove categorically that probability
distributions leave open a choice of quantum states and operators and
particles, resolvable only by a move beyond logic, which, inspired or not, can
be characterized as a guess. By recognizing guesswork as inescapable in
choosing quantum states and particles, we free up the use of particles as
theoretical inventions by which to describe experiments with devices, and
thereby replace the postulate of state reductions by a theorem. By using the
freedom to invent probe particles in modeling light detection, we develop a
quantum model of the balancing of a light-induced force, with application to
models and detecting devices by which to better distinguish one source of weak
light from another. Finally, we uncover a symmetry between entangled states and
entangled detectors, a dramatic example of how the judgment about what light
state is generated by a source depends on choosing how to model the detector of
that light.Comment: 30 pages, 4 figs, LaTeX; new Introduction; new material in Secs. 4 &
5; new Sec. 6; 1 new figure, added reference
Simulations of Alice Electrodynamics on a Lattice
In this paper we present results of numerical simulations and some
(analytical) approximations of a compact U(1)\ltimes\ZZ_2 lattice gauge
theory, including an extra bare mass term for Alice fluxes. The subtle
interplay between Alice fluxes and (Cheshire) magnetic charges is analysed. We
determine the phase diagram and some characteristics of the model in three and
four dimensions. The results of the numerical simulations in various regimes,
compare well with some analytic approximations.Comment: 17 pages, 16 figures; minor change
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