671 research outputs found
Spin Gap in the Single Spin-1/2 Chain Cuprate SrCaCuO
We report Cu nuclear magnetic resonance and muon spin rotation
measurements on the S=1/2 antiferromagnetic Heisenberg spin chain compound
SrCaCuO. An exponentially decreasing spin-lattice
relaxation rate 1/T indicates the opening of a spin gap. This behavior is
very similar to what has been observed for the cognate zigzag spin chain
compound SrCaCuO, and confirms that the occurrence of a
spin gap upon Ca doping is independent of the interchain exchange coupling
. Our results therefore generally prove the appearance of a spin gap in an
antiferromagnetic Heisenberg spin chain induced by a local bond disorder of the
intrachain exchange coupling . A low temperature upturn of 1/T evidences
growing magnetic correlations. However, zero field muon spin rotation
measurements down to 1.5 K confirm the absence of magnetic order in this
compound which is most likely suppressed by the opening of the spin gap.Comment: 5 pages, 4 figure
Heterogeneity of T-cell receptor alpha-chain complementarity-determining region 3 in myelin basic protein-specific T cells increases with severity of multiple sclerosis.
Energy landscapes, ideal glasses, and their equation of state
Using the inherent structure formalism originally proposed by Stillinger and
Weber [Phys. Rev. A 25, 978 (1982)], we generalize the thermodynamics of an
energy landscape that has an ideal glass transition and derive the consequences
for its equation of state. In doing so, we identify a separation of
configurational and vibrational contributions to the pressure that corresponds
with simulation studies performed in the inherent structure formalism. We
develop an elementary model of landscapes appropriate to simple liquids which
is based on the scaling properties of the soft-sphere potential complemented
with a mean-field attraction. The resulting equation of state provides an
accurate representation of simulation data for the Lennard-Jones fluid,
suggesting the usefulness of a landscape-based formulation of supercooled
liquid thermodynamics. Finally, we consider the implications of both the
general theory and the model with respect to the so-called Sastry density and
the ideal glass transition. Our analysis shows that a quantitative connection
can be made between properties of the landscape and a simulation-determined
Sastry density, and it emphasizes the distinction between an ideal glass
transition and a Kauzmann equal-entropy condition.Comment: 11 pages, 3 figure
Update of the Swiss source model for road traffic noise
In Switzerland, the calculation method of road traffic noise is specified in the Ordonnance sur la protection contre le bruit (OPB) (Noise Protection Ordonnance (NPO)). This method is mainly based on observations that were realized in the 80s, and that are not satisfactory many situations anymore. Since the 80s, the traffic volumes have increased, new developments in car and road technologies have occurred, behaviors of users have changed. All these parame-ters contribute to lower reliability of the initial method. Even if the model is still correct in some case such as for fluid traffic, the obtained levels in different types of traffic are hardly reliable. In collaboration with the Swiss Federal Office for the Environment (FOEN), a re-search program has been setup to update the method according to those observations. The ob-jective was to give new guidelines to evaluate emission levels of roads. An important collect of data from cantons and others acoustics partners has been performed as well as measure-ments in real traffic conditions. That made it possible to gather about 7500 points of mea-surement through all Switzerland for several types of road and traffic conditions
Concomitant Carcinoma in situ in Cystectomy Specimens Is Not Associated with Clinical Outcomes after Surgery
Objective: The aim of this study was to externally validate the prognostic value of concomitant urothelial carcinoma in situ (CIS) in radical cystectomy (RC) specimens using a large international cohort of bladder cancer patients. Methods: The records of 3,973 patients treated with RC and bilateral lymphadenectomy for urothelial carcinoma of the bladder (UCB) at nine centers worldwide were reviewed. Surgical specimens were evaluated by a genitourinary pathologist at each center. Uni- and multivariable Cox regression models addressed time to recurrence and cancer-specific mortality after RC. Results: 1,741 (43.8%) patients had concomitant CIS in their RC specimens. Concomitant CIS was more common in organ-confined UCB and was associated with lymphovascular invasion (p < 0.001). Concomitant CIS was not associated with either disease recurrence or cancer-specific death regardless of pathologic stage. The presence of concomitant CIS did not improve the predictive accuracy of standard predictors for either disease recurrence or cancer-specific death in any of the subgroups. Conclusions: We could not confirm the prognostic value of concomitant CIS in RC specimens. This, together with the discrepancy between pathologists in determining the presence of concomitant CIS at the morphologic level, limits the clinical utility of concomitant CIS in RC specimens for clinical decision-making. Copyright (C) 2011 S. Karger AG, Base
QTL mapping of improving forage maize starch degradability in European elite maize germplasm
Improving maize starch content is of great importance for both forage and grain yield. In this study, 13 starch degradability traits were analyzed including percentage of the seedling area, floury endosperm, hard endosperm of total grain area, percentage of the floury endosperm surface, and vitreousness ratio surface hard: floury endosperm surface, etc. We mapped quantitative trait loci (QTL) in a biparental population of 309 doubled haploid lines (DHL) based on field phenotyping at two locations. A genetic linkage map was constructed using 168 SSR (simple sequence repeat) markers, which covered 1508 cM of the maize genome, with an average distance of 9.0 cM. Close phenotypic and genotypic correlations were found for all traits, and were all statistically significant (P = 0.01) at two locations. Major QTL for more than two traits were detected, especially in two regions in bins 4.05-4.06 and 7.04-7.05, associated with 13 and 9 traits, respectively. This study contributes to marker assisted breeding and also to fine mapping candidate genes associated with maize starch degradability
The All-Data-Based Evolutionary Hypothesis of Ciliated Protists with a Revised Classification of the Phylum Ciliophora (Eukaryota, Alveolata)
This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ The file attached is the published version of the article
Plastic Flow in Two-Dimensional Solids
A time-dependent Ginzburg-Landau model of plastic deformation in
two-dimensional solids is presented. The fundamental dynamic variables are the
displacement field \bi u and the lattice velocity {\bi v}=\p {\bi u}/\p t.
Damping is assumed to arise from the shear viscosity in the momentum equation.
The elastic energy density is a periodic function of the shear and tetragonal
strains, which enables formation of slips at large strains. In this work we
neglect defects such as vacancies, interstitials, or grain boundaries. The
simplest slip consists of two edge dislocations with opposite Burgers vectors.
The formation energy of a slip is minimized if its orientation is parallel or
perpendicular to the flow in simple shear deformation and if it makes angles of
with respect to the stretched direction in uniaxial stretching.
High-density dislocations produced in plastic flow do not disappear even if
the flow is stopped. Thus large applied strains give rise to metastable,
structurally disordered states. We divide the elastic energy into an elastic
part due to affine deformation and a defect part. The latter represents degree
of disorder and is nearly constant in plastic flow under cyclic straining.Comment: 16pages, Figures can be obtained at
http://stat.scphys.kyoto-u.ac.jp/index-e.htm
Evidences of vortex curvature and anisotropic pinning in superconducting films by quantitative magneto-optics
We present the experimental observation of magnetic field line curvature at
the surface of a superconducting film by local quantitative magneto-optics. In
addition to the knowledge of the full induction field at the superconductor
surface yielding the quantitative observation of the flux line curvature, our
analysis method allows also local value measurements of the electrical current
density inside the sample. Thus, we study the interplay between the
electrodynamic constraints dictated by the film geometry and the pinning
properties of the superconductor. In particular, we investigate the anisotropic
vortex-pinning, due to columnar defects introduced by heavy ion irradiation, as
revealed in the local current density dependence on the vortex curvature during
magnetic flux diffusion inside the superconducting film.Comment: 12 pages, 11 figures, to be submitted to Phys. Rev.
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