11,752 research outputs found
Control of multiferroic domains by external electric fields in TbMnO3
The control of multiferroic domains through external electric fields has been
studied by dielectric measurements and by polarized neutron diffraction on
single-crystalline TbMnO. Full hysteresis cycles were recorded by varying
an external field of the order of several kV/mm and by recording the chiral
magnetic scattering as well as the charge in a sample capacitor. Both methods
yield comparable coercive fields that increase upon cooling.Comment: 12 pages, 6 figure
Large-time Behavior of Solutions to the Inflow Problem of Full Compressible Navier-Stokes Equations
Large-time behavior of solutions to the inflow problem of full compressible
Navier-Stokes equations is investigated on the half line .
The wave structure which contains four waves: the transonic(or degenerate)
boundary layer solution, 1-rarefaction wave, viscous 2-contact wave and
3-rarefaction wave to the inflow problem is described and the asymptotic
stability of the superposition of the above four wave patterns to the inflow
problem of full compressible Navier-Stokes equations is proven under some
smallness conditions. The proof is given by the elementary energy analysis
based on the underlying wave structure. The main points in the proof are the
degeneracies of the transonic boundary layer solution and the wave interactions
in the superposition wave.Comment: 27 page
Development of fuel cell electrodes, Electrode improvement and life testing, tasks 1 and 3 Final report, 30 Jun. 1966 - 30 Apr. 1968
Volt-ampere characteristics improvement and life testing of electrodes for hydrogen oxygen fuel cell
Parameter estimation in pair hidden Markov models
This paper deals with parameter estimation in pair hidden Markov models
(pair-HMMs). We first provide a rigorous formalism for these models and discuss
possible definitions of likelihoods. The model being biologically motivated,
some restrictions with respect to the full parameter space naturally occur.
Existence of two different Information divergence rates is established and
divergence property (namely positivity at values different from the true one)
is shown under additional assumptions. This yields consistency for the
parameter in parametrization schemes for which the divergence property holds.
Simulations illustrate different cases which are not covered by our results.Comment: corrected typo
WFPC2 LRF Imaging of Emission Line Nebulae in 3CR Radio Galaxies
We present HST/WFPC2 Linear Ramp Filter images of high surface brightness
emission lines (either [OII], [OIII], or H-alpha+[NII]) in 80 3CR radio
sources. We overlay the emission line images on high resolution VLA radio
images (eight of which are new reductions of archival data) in order to examine
the spatial relationship between the optical and radio emission. We confirm
that the radio and optical emission line structures are consistent with weak
alignment at low redshift (z < 0.6) except in the Compact Steep Spectrum (CSS)
radio galaxies where both the radio source and the emission line nebulae are on
galactic scales and strong alignment is seen at all redshifts. There are weak
trends for the aligned emission line nebulae to be more luminous, and for the
emission line nebula size to increase with redshift and/or radio power. The
combination of these results suggests that there is a limited but real capacity
for the radio source to influence the properties of the emission line nebulae
at these low redshifts (z < 0.6). Our results are consistent with previous
suggestions that both mechanical and radiant energy are responsible for
generating alignment between the radio source and emission line gas.Comment: 80 pages, 54 figures. Accepted for publication in ApJ
Expectation adjustment in the housing market: insights from the Scottish auction system
This paper examines price expectation adjustment of house buyers and sellers to rapid changes in the housing market using data from Scotland where houses are sold through 'first-price sealed-bid' auctions. These auctions provide more information on market signals, incentives and the behaviour of market participants than private treaty sales. This paper therefore provides a theoretical framework for analysing revealed preference data generated from these auctions. We specifically focus on the analysis of the selling to asking price difference, the 'bid-premium'. The bid-premium is shown to be affected by expectations of future price movements, market duration and high bidding frequency. The bid-premium reflects consumers' expectations, adapting to market conditions more promptly than asking price setting behaviour and final sale prices. The volatile conditions of the recent housing market bubble are fully reflected in the bid-premium, whereas the asking and sale prices are much less prone to rapid movements
Multimodality Biomedical Image Registration using Free Point Transformer Networks
We describe a point-set registration algorithm based on a novel free point
transformer (FPT) network, designed for points extracted from multimodal
biomedical images for registration tasks, such as those frequently encountered
in ultrasound-guided interventional procedures. FPT is constructed with a
global feature extractor which accepts unordered source and target point-sets
of variable size. The extracted features are conditioned by a shared multilayer
perceptron point transformer module to predict a displacement vector for each
source point, transforming it into the target space. The point transformer
module assumes no vicinity or smoothness in predicting spatial transformation
and, together with the global feature extractor, is trained in a data-driven
fashion with an unsupervised loss function. In a multimodal registration task
using prostate MR and sparsely acquired ultrasound images, FPT yields
comparable or improved results over other rigid and non-rigid registration
methods. This demonstrates the versatility of FPT to learn registration
directly from real, clinical training data and to generalize to a challenging
task, such as the interventional application presented.Comment: 10 pages, 4 figures. Accepted for publication at International
Conference on Medical Image Computing and Computer Assisted Intervention
(MICCAI) workshop on Advances in Simplifying Medical UltraSound (ASMUS) 202
Does the act of surgery provoke activation of "latent" metastases in early breast cancer?
This paper is written in support of the challenging article by Retsky and colleagues in this issue of Breast Cancer Research, and develops on the idea that the act of surgery can provoke the outgrowth of dormant micrometastases, which often leads to the failure of screening to deliver its promise. The therapeutic consequence of this idea involves the use of antiangiogenic drugs before surgery
- …