22,005 research outputs found
Using film cutting in interface design
It has been suggested that computer interfaces could be made more usable if their designers utilized cinematography techniques, which have evolved to guide
the viewer through a narrative despite frequent discontinuities in the presented scene (i.e., cuts between shots). Because of differences between the domains of
film and interface design, it is not straightforward to understand how such techniques can be transferred. May and Barnard (1995) argued that a psychological
model of watching film could support such a transference. This article presents an extended account of this model, which allows identification of the practice of collocation
of objects of interest in the same screen position before and after a cut. To verify that filmmakers do, in fact, use such techniques successfully, eye movements
were measured while participants watched the entirety of a commerciall
On the heterogeneous character of water's amorphous polymorphism
In this letter we report {\it in situ} small--angle neutron scattering
results on the high--density (HDA) and low-density amorphous (LDA) ice
structures and on intermediate structures as found during the temperature
induced transformation of HDA into LDA. We show that the small--angle signal is
characterised by two regimes featuring different properties ( is the
modulus of the scattering vector defined as with being half the scattering
angle and the incident neutron wavelength). The very low--
regime ( \AA ) is dominated by a Porod--limit
scattering. Its intensity reduces in the course of the HDA to LDA
transformation following a kinetics reminiscent of that observed in wide--angle
diffraction experiments. The small--angle neutron scattering formfactor in the
intermediate regime of \AA HDA and LDA
features a rather flat plateau. However, the HDA signal shows an ascending
intensity towards smaller marking this amorphous structure as
heterogeneous. When following the HDA to LDA transition the formfactor shows a
pronounced transient excess in intensity marking all intermediate structures as
strongly heterogeneous on a length scale of some nano--meters
Agenda for Change: views and experiences from estates and facilities staff
Purpose – Agenda for Change is the biggest reform of staff pay in the UK National Health Service NHS) since it began in 1948. As well as introducing a standardised pay structure; it also aims to improve recruitment, retention and staff morale. The aim of this study is to look in-depth at the experiences and opinions of a range of estates and facilities staff surrounding Agenda for Change during the implementation period. Design/methodology/approach – Focus groups were used as the primary method of data collection in an attempt to tap into the views and opinions of staff working at operational positions in a wide range of trusts. Findings – One of the most important and common themes, which reoccurred throughout the focus groups, was the view that the Agenda for Change framework was designed around the needs of nursing staff. Therefore, the framework did not adequately cater for the needs of estates and facilities staff. Specific concerns related to this included; the role or contribution of estates and facilities staff during patient care was not fairly reflected; trade qualifications were not recognised, particularly in comparison to academic qualifications; members of the job matching panels did not have the appropriate knowledge to make decisions surrounding estates and facilities jobs; nurses were more likely to make progress through the bands than estates and facilities staff.</p
Energy transfer in finite-size exciton-phonon systems : confinement-enhanced quantum decoherence
Based on the operatorial formulation of the perturbation theory, the
exciton-phonon problem is revisited for investigating exciton-mediated energy
flow in a finite-size lattice. Within this method, the exciton-phonon
entanglement is taken into account through a dual dressing mechanism so that
exciton and phonons are treated on an equal footing. In a marked contrast with
what happens in an infinite lattice, it is shown that the dynamics of the
exciton density is governed by several time scales. The density evolves
coherently in the short-time limit whereas a relaxation mechanism occurs over
intermediated time scales. Consequently, in the long-time limit, the density
converges toward a nearly uniform distributed equilibrium distribution. Such a
behavior results from quantum decoherence that originates in the fact that the
phonons evolve differently depending on the path followed by the exciton to
tunnel along the lattice. Although the relaxation rate increases with the
temperature and with the coupling, it decreases with the lattice size,
suggesting that the decoherence is inherent to the confinement
Clustering in complex networks. II. Percolation properties
The percolation properties of clustered networks are analyzed in detail. In
the case of weak clustering, we present an analytical approach that allows to
find the critical threshold and the size of the giant component. Numerical
simulations confirm the accuracy of our results. In more general terms, we show
that weak clustering hinders the onset of the giant component whereas strong
clustering favors its appearance. This is a direct consequence of the
differences in the -core structure of the networks, which are found to be
totally different depending on the level of clustering. An empirical analysis
of a real social network confirms our predictions.Comment: Updated reference lis
Heteroclinic Chaos, Chaotic Itinerancy and Neutral Attractors in Symmetrical Replicator Equations with Mutations
A replicator equation with mutation processes is numerically studied.
Without any mutations, two characteristics of the replicator dynamics are
known: an exponential divergence of the dominance period, and hierarchical
orderings of the attractors. A mutation introduces some new aspects: the
emergence of structurally stable attractors, and chaotic itinerant behavior. In
addition, it is reported that a neutral attractor can exist in the mutataion
rate -> +0 region.Comment: 4 pages, 9 figure
Eigenvalue Separation in Some Random Matrix Models
The eigenvalue density for members of the Gaussian orthogonal and unitary
ensembles follows the Wigner semi-circle law. If the Gaussian entries are all
shifted by a constant amount c/Sqrt(2N), where N is the size of the matrix, in
the large N limit a single eigenvalue will separate from the support of the
Wigner semi-circle provided c > 1. In this study, using an asymptotic analysis
of the secular equation for the eigenvalue condition, we compare this effect to
analogous effects occurring in general variance Wishart matrices and matrices
from the shifted mean chiral ensemble. We undertake an analogous comparative
study of eigenvalue separation properties when the size of the matrices are
fixed and c goes to infinity, and higher rank analogues of this setting. This
is done using exact expressions for eigenvalue probability densities in terms
of generalized hypergeometric functions, and using the interpretation of the
latter as a Green function in the Dyson Brownian motion model. For the shifted
mean Gaussian unitary ensemble and its analogues an alternative approach is to
use exact expressions for the correlation functions in terms of classical
orthogonal polynomials and associated multiple generalizations. By using these
exact expressions to compute and plot the eigenvalue density, illustrations of
the various eigenvalue separation effects are obtained.Comment: 25 pages, 9 figures include
Multipartite entanglement in the Fenna-Matthews-Olson (FMO) pigment-protein complex
We investigate multipartite states in the Fenna-Matthews-Olson (FMO)
pigment-protein complex of the green sulfur bacteria using a Lorentzian
spectral density of the phonon reservoir fitted with typical parameter
estimates of the species, P. aestuarii. The evolution of the entanglement
measure of the excitonic W qubit states is evaluated in the picosecond time
range, showing increased revivals in the non-Markovian regime. Similar trends
are observed in the evolution dynamics of the Meyer-Wallach measure of the
N-exciton multipartite state, with results showing that multipartite
entanglement can last from 0.5 to 1 ps, between the Bchls of the FMO complex.
The teleportation and quantum information splitting fidelities associated with
the GHZ and W_A resource states of the excitonic qubit channels of the FMO
complex show that revivals in fidelities increase with the degree of
non-Markovian strength of the decoherent environment. Results indicate that
quantum information processing tasks involving teleportation followed by the
decodification process involving W_A states of the FMO complex, may play a
critical role during coherent oscillations at physiological temperatures.Comment: 16 pages, new figs, typo
Systems, interactions and macrotheory
A significant proportion of early HCI research was guided by one very clear vision: that the existing theory base in psychology and cognitive science could be developed to yield engineering tools for use in the interdisciplinary context of HCI design. While interface technologies and heuristic methods for behavioral evaluation have rapidly advanced in both capability and breadth of application, progress toward deeper theory has been modest, and some now believe it to be unnecessary. A case is presented for developing new forms of theory, based around generic “systems of interactors.” An overlapping, layered structure of macro- and microtheories could then serve an explanatory role, and could also bind together contributions from the different disciplines. Novel routes to formalizing and applying such theories provide a host of interesting and tractable problems for future basic research in HCI
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