19,882 research outputs found
Signaling pathways in osteogenesis and osteoclastogenesis: Lessons from cranial sutures and applications to regenerative medicine.
One of the simplest models for examining the interplay between bone formation and resorption is the junction between the cranial bones. Although only roughly a quarter of patients diagnosed with craniosynostosis have been linked to known genetic disturbances, the molecular mechanisms elucidated from these studies have provided basic knowledge of bone homeostasis. This work has translated to methods and advances in bone tissue engineering. In this review, we examine the current knowledge of cranial suture biology derived from human craniosynostosis syndromes and discuss its application to regenerative medicine
Properties of the stochastic Gross-Pitaevskii equation: Projected Ehrenfest relations and the optimal plane wave basis
We investigate the properties of the stochastic Gross-Pitaevskii equation
describing a condensate interacting with a stationary thermal cloud derived by
Gardiner and coworkers. We find the appropriate Ehrenfest relations for the
SGPE, including the effect of growth noise and projector terms arising from the
energy cutoff. This is carried out in the high temperature regime appropriate
for the SGPE, which simplifies the action of the projectors. The validity
condition for neglecting the projector terms in the Ehrenfest relations is
found to be more stringent than the usual condition of validity of the
truncated Wigner method or classical field method -- which is that all modes
are highly occupied. In addition it is required that the overlap of the
nonlinear term with the lowest energy eigenstate of the non-condensate band is
small. We show how to use the Ehrenfest relations along with the corrections
generated by the projector to monitor dynamical artifacts arising from the
cutoff. We also investigate the effect of using different bases to describe a
harmonically trapped BEC at finite temperature by comparing the condensate
fraction found using the plane wave and single particle bases. We show that the
equilibrium properties are strongly dependent on the choice of basis. There is
thus an optimal choice of plane wave basis for a given cut-off energy and we
show that this basis gives the best reproduction of the single particle
spectrum, the condensate fraction and the position and momentum densities.Comment: 23 pages, 5 figure
Mumford dendrograms and discrete p-adic symmetries
In this article, we present an effective encoding of dendrograms by embedding
them into the Bruhat-Tits trees associated to -adic number fields. As an
application, we show how strings over a finite alphabet can be encoded in
cyclotomic extensions of and discuss -adic DNA encoding. The
application leads to fast -adic agglomerative hierarchic algorithms similar
to the ones recently used e.g. by A. Khrennikov and others. From the viewpoint
of -adic geometry, to encode a dendrogram in a -adic field means
to fix a set of -rational punctures on the -adic projective line
. To is associated in a natural way a
subtree inside the Bruhat-Tits tree which recovers , a method first used by
F. Kato in 1999 in the classification of discrete subgroups of
.
Next, we show how the -adic moduli space of
with punctures can be applied to the study of time series of
dendrograms and those symmetries arising from hyperbolic actions on
. In this way, we can associate to certain classes of dynamical
systems a Mumford curve, i.e. a -adic algebraic curve with totally
degenerate reduction modulo .
Finally, we indicate some of our results in the study of general discrete
actions on , and their relation to -adic Hurwitz spaces.Comment: 14 pages, 6 figure
Estimation and optimal designing under latent variable models for paired comparisons studies via a multiplicative algorithm
We consider:<BR/>
1. The problem of estimating the parameters of latent variable models such as the Bradley Terry or Thurstone Model by the method of maximum likelihood, given data from a paired comparisons experiment. The parameters of these models can be taken to be weights which are positive and sum to one;<BR/>
2. The problem of determining approximate locally optimal designs for good estimation of these parameters; i.e of determining optimal design weights which are also positive and sum to one
A NOVEL BEDSIDE COMMUNICATION TOOL
Effective communication between patients, their families, their carers and health care professionals is paramount to the delivery
of high quality care. Addressing the ideas, concerns and expectations of these groups may improve their healthcare experience.
We propose that opening a new channel of communication between patients, families, carers and healthcare professionals on the
wards would improve the delivery of healthcare. We present a novel written communication aid- the Care Communication Aid
(CCA), with preliminary data from secondary and tertiary healthcare trials demonstrating its efficacy and shortcomings, and the
reaction of both recipients and providers of healthcare to this novel approach
Ground-State Properties of a Rotating Bose-Einstein Condensate with Attractive Interaction
The ground state of a rotating Bose-Einstein condensate with attractive
interaction in a quasi-one-dimensional torus is studied in terms of the ratio
of the mean-field interaction energy per particle to the
single-particle energy-level spacing. The plateaus of quantized circulation are
found to appear if and only if with the lengths of the plateaus
reduced due to hybridization of the condensate over different angular-momentum
states.Comment: 4 pages, 2 figures, Accepted for publication in Physical Reveiw
Letter
Suppression of Kelvon-induced decay of quantized vortices in oblate Bose-Einstein Condensates
We study the Kelvin mode excitations on a vortex line in a three-dimensional
trapped Bose-Einstein condensate at finite temperature. Our stochastic
Gross-Pitaevskii simulations show that the activation of these modes can be
suppressed by tightening the confinement along the direction of the vortex
line, leading to a strong suppression in the vortex decay rate as the system
enters a regime of two-dimensional vortex dynamics. As the system approaches
the condensation transition temperature we find that the vortex decay rate is
strongly sensitive to dimensionality and temperature, observing a large
enhancement for quasi-two-dimensional traps. Three-dimensional simulations of
the recent vortex dipole decay experiment of Neely et al. [Phys. Rev. Lett.
104, 160401 (2010)] confirm two-dimensional vortex dynamics, and predict a
dipole lifetime consistent with experimental observations and suppression of
Kelvon-induced vortex decay in highly oblate condensates.Comment: 8 pages, 8 figure
- …