934 research outputs found
PMS48 Cost-Effectiveness of Tocilizumab for The Management of Inadequately Responding Rheumatoid Arthritis Patients
Weiner, LawrencePrimer pla de l'obra. Tres grans
paral·lelepípedes de formigó, amb
aparença de sarcòfags.Repartits al llarg
de l'avinguda. Tots porten uns versos,
escrits el 1845, quan tenia 15 anys, pel
premi Nobel Frederic Mistral
S=1 kagom\'e Ising model with triquadratic interactions, single-ion anisotropy and magnetic field: exact phase diagrams
We consider a S=1 kagom\'e Ising model with triquadratic interactions around
each triangular face of the kagom\'e lattice, single-ion anisotropy and an
applied magnetic field. A mapping establishes an equivalence between the
magnetic canonical partition function of the model and the grand canonical
partition function of a kagom\'e lattice-gas model with localized
three-particle interactions. Since exact phase diagrams are known for
condensation in the one-parameter lattice-gas model, the mapping directly
provides the corresponding exact phase diagrams of the three-parameter S=1
Ising model. As anisotropy competes with interactions, results include the
appearance of confluent singularities effecting changes in the topology of the
phase diagrams, phase boundary curves (magnetic field vs temperature) with
purely positive or negative slopes as well as intermediate cases showing
nonmonotonicity, and coexistence curves (magnetization vs temperature) with
varying shapes and orientations, in some instances entrapping a homogeneous
phase.Comment: 14 pages plus 11 figures; to be published in Physica
Constructive Dimension and Turing Degrees
This paper examines the constructive Hausdorff and packing dimensions of
Turing degrees. The main result is that every infinite sequence S with
constructive Hausdorff dimension dim_H(S) and constructive packing dimension
dim_P(S) is Turing equivalent to a sequence R with dim_H(R) <= (dim_H(S) /
dim_P(S)) - epsilon, for arbitrary epsilon > 0. Furthermore, if dim_P(S) > 0,
then dim_P(R) >= 1 - epsilon. The reduction thus serves as a *randomness
extractor* that increases the algorithmic randomness of S, as measured by
constructive dimension.
A number of applications of this result shed new light on the constructive
dimensions of Turing degrees. A lower bound of dim_H(S) / dim_P(S) is shown to
hold for the Turing degree of any sequence S. A new proof is given of a
previously-known zero-one law for the constructive packing dimension of Turing
degrees. It is also shown that, for any regular sequence S (that is, dim_H(S) =
dim_P(S)) such that dim_H(S) > 0, the Turing degree of S has constructive
Hausdorff and packing dimension equal to 1.
Finally, it is shown that no single Turing reduction can be a universal
constructive Hausdorff dimension extractor, and that bounded Turing reductions
cannot extract constructive Hausdorff dimension. We also exhibit sequences on
which weak truth-table and bounded Turing reductions differ in their ability to
extract dimension.Comment: The version of this paper appearing in Theory of Computing Systems,
45(4):740-755, 2009, had an error in the proof of Theorem 2.4, due to
insufficient care with the choice of delta. This version modifies that proof
to fix the error
Universal fluctuations in subdiffusive transport
Subdiffusive transport in tilted washboard potentials is studied within the
fractional Fokker-Planck equation approach, using the associated continuous
time random walk (CTRW) framework. The scaled subvelocity is shown to obey a
universal law, assuming the form of a stationary Levy-stable distribution. The
latter is defined by the index of subdiffusion alpha and the mean subvelocity
only, but interestingly depends neither on the bias strength nor on the
specific form of the potential. These scaled, universal subvelocity
fluctuations emerge due to the weak ergodicity breaking and are vanishing in
the limit of normal diffusion. The results of the analytical heuristic theory
are corroborated by Monte Carlo simulations of the underlying CTRW
Recommended from our members
Smart packaging for photonics
Unlike silicon microelectronics, photonics packaging has proven to be low yield and expensive. One approach to make photonics packaging practical for low cost applications is the use of {open_quotes}smart{close_quotes} packages. {open_quotes}Smart{close_quotes} in this context means the ability of the package to actuate a mechanical change based on either a measurement taken by the package itself or by an input signal based on an external measurement. One avenue of smart photonics packaging, the use of polysilicon micromechanical devices integrated with photonic waveguides, was investigated in this research (LDRD 3505.340). The integration of optical components with polysilicon surface micromechanical actuation mechanisms shows significant promise for signal switching, fiber alignment, and optical sensing applications. The optical and stress properties of the oxides and nitrides considered for optical waveguides and how they are integrated with micromechanical devices were investigated
The PKC, HOG and Ca2+ signalling pathways co-ordinately regulate chitin synthesis in Candida albicans
Open Access via PMC2649417Peer reviewedPublisher PD
Polynomial diffeomorphisms of C^2, IV: The measure of maximal entropy and laminar currents
This paper concerns the dynamics of polynomial automorphisms of .
One can associate to such an automorphism two currents and the
equilibrium measure . In this paper we study some
geometric and dynamical properties of these objects. First, we characterize
as the unique measure of maximal entropy. Then we show that the measure
has a local product structure and that the currents have a
laminar structure. This allows us to deduce information about periodic points
and heteroclinic intersections. For example, we prove that the support of
coincides with the closure of the set of saddle points. The methods used
combine the pluripotential theory with the theory of non-uniformly hyperbolic
dynamical systems
Unstimulated cortisol secretory activity in everyday life and its relationship with fatigue and chronic fatigue syndrome : a systematic review and subset meta-analysis
Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.Peer reviewedPublisher PD
Gravitational collapse of a Hagedorn fluid in Vaidya geometry
The gravitational collapse of a high-density null charged matter fluid,
satisfying the Hagedorn equation of state, is considered in the framework of
the Vaidya geometry. The general solution of the gravitational field equations
can be obtained in an exact parametric form. The conditions for the formation
of a naked singularity, as a result of the collapse of the compact object, are
also investigated. For an appropriate choice of the arbitrary integration
functions the null radial outgoing geodesic, originating from the shell
focussing central singularity, admits one or more positive roots. Hence a
collapsing Hagedorn fluid could end either as a black hole, or as a naked
singularity. A possible astrophysical application of the model, to describe the
energy source of gamma-ray bursts, is also considered.Comment: 14 pages, 2 figures, to appear in Phys. Rev.
- …