26,775 research outputs found
Holder exponent spectra for human gait
The stride interval time series in normal human gait is not strictly
constant, but fluctuates from step to step in a complex manner. More precisely,
it has been shown that the control process for human gait is a fractal random
phenomenon, that is, one with a long-term memory. Herein we study the Holder
exponent spectra for the slow, normal and fast gaits of 10 young healthy men in
both free and metronomically triggered conditions and establish that the stride
interval time series is more complex than a monofractal phenomenon. A slightly
multifractal and non-stationary time series under the three different gait
conditions emerges.Comment: 23 pages, 12 figures, 9 Table
A history of biographical research in the United Kingdom
Biograpahical researchers in the United Kingdom have been influenced by symbolic interactionism, feminism, oral history, critical sociology, psychoanalysis and what we term an auto/biographical imagination. The latter involves reflexively situating the researcher and her influence, via power, unconscious processes and writing, into the text and by acknowledging the co-construction of stories.
The focus of much research has been on marginalised peoples, as part of a democratising project to bring more diverse voices and stories into the historical or contemporary social record. It is important to avoid too rigid a distinction between mainland Europe and developments in Britain. Collaboration and dialogue have been extensive, across various research networks, including in the European Society for Research in the Education of Adults (ESREA)
On Holomorphic Effective Actions of Hypermultiplets Coupled to External Gauge Superfields
We study the structure of holomorphic effective action for hypermultiplet
models interacting with background super Yang-Mills fields. A general form of
holomorphic effective action is found for hypermultiplet belonging to arbitrary
representation of any semisimple compact Lie group spontaneously broken to its
maximal abelian subgroup. The applications of obtained results to
hypermultiplets in fundamental and adjoint representations of the SU(n), SO(n),
Sp(n) groups are considered.Comment: 8 pages, no figure
Non-Poisson dichotomous noise: higher-order correlation functions and aging
We study a two-state symmetric noise, with a given waiting time distribution
, and focus our attention on the connection between the four-time
and the two-time correlation functions. The transition of from
the exponential to the non-exponential condition yields the breakdown of the
usual factorization condition of high-order correlation functions, as well as
the birth of aging effects. We discuss the subtle connections between these two
properties, and establish the condition that the Liouville-like approach has to
satisfy in order to produce a correct description of the resulting diffusion
process
Non-Poisson dichotomous noise: higher-order correlation functions and aging
We study a two-state symmetric noise, with a given waiting time distribution
, and focus our attention on the connection between the four-time
and the two-time correlation functions. The transition of from
the exponential to the non-exponential condition yields the breakdown of the
usual factorization condition of high-order correlation functions, as well as
the birth of aging effects. We discuss the subtle connections between these two
properties, and establish the condition that the Liouville-like approach has to
satisfy in order to produce a correct description of the resulting diffusion
process
Actively Tuned and Spatially Trapped Polaritons
We report active tuning of the polariton resonance of quantum well excitons
in a semiconductor microcavity using applied stress. Starting with the quantum
well exciton energy higher than the cavity photon mode, we use stress to reduce
the exciton energy and bring it into resonance with the photon mode. At the
point of zero detuning, line narrowing and strong increase of the
photoluminescence are seen. By the same means, we create an in-plane harmonic
potential for the polaritons, which allows trapping, potentially making
Bose-Einstein condensation of polaritons analogous to trapped atoms possible.
We demonstrate drift of the polaritons into this trap.Comment: 10 pages, 5 figure
Galaxy Orientations in the Coma Cluster
We have examined the orientations of early-type galaxies in the Coma cluster
to see whether the well-established tendency for brightest cluster galaxies to
share the same major axis orientation as their host cluster also extends to the
rest of the galaxy population. We find no evidence of any preferential
orientations of galaxies within Coma or its surroundings. The implications of
this result for theories of the formation of clusters and galaxies
(particularly the first-ranked members) are discussed.Comment: Accepted for publication in the Astrophysical Journal Letters. 4
pages, 4 figure
Metastable Resistance Anisotropy Orientation of Two-Dimensional Electrons in High Landau Levels
In half-filled high Landau levels, two-dimensional electron systems possess
collective phases which exhibit a strongly anisotropic resistivity tensor. A
weak, but as yet unknown, rotational symmetry-breaking potential native to the
host semiconductor structure is necessary to orient these phases in macroscopic
samples. Making use of the known external symmetry-breaking effect of an
in-plane magnetic field, we find that the native potential can have two
orthogonal local minima. It is possible to initialize the system in the higher
minimum and then observe its relaxation toward equilibrium.Comment: 5 pages, 3 figures. Figure references corrected. Version accepted for
publication in Physical Review Letter
On the relation between nuclear and nucleon Structure Functions and their moments
Calculations of nuclear Structure Functions (SF) F_k^A(x,Q^2) routinely
exploit a generalized convolution, involving the SF for nucleons F_k^N and the
linking SF f^{PN,A} of a fictitious nucleus, composed of point-particles, with
the latter usually expressed in terms of hadronic degrees of freedom. For
finite Q^2 the approach seemed to be lacking a solid justification and the same
is the case for recently proposed, effective nuclear parton distribution
functions (pdf), which exactly reproduce the above-mentioned hadronically
computed F_k^A. Many years ago Jaffe and West proved the above convolution in
the Plane Wave Impulse Approximation (PWIA) for the nuclear components in the
convolution. In the present note we extend the above proof to include classes
of nuclear Final State Interactions (FSI). One and the same function appears to
relate parton distribution functions (pdf) in nuclei and nucleons, and SF for
nuclear targets and for nucleons. That relation is the previously conjectured
one,with an entirely different interpretation of f^{PN,A}. We conclude with an
extensive analysis of moments of nuclear SF based on the generalized
convolution. Characteristics of those moments are shown to be quite similar to
the same for a nucleon. We conclude that the above evidences asymptotic freedom
of a nucleon in a medium and not of a composite nucleus.Comment: 18 pages, 9 figure
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