6,251 research outputs found
Incommensurate phonon anomaly and the nature of charge density waves in cuprates
While charge density wave (CDW) instabilities are ubiquitous to
superconducting cuprates, the different ordering wavevectors in various cuprate
families have hampered a unified description of the CDW formation mechanism.
Here we investigate the temperature dependence of the low energy phonons in the
canonical CDW ordered cuprate LaBaCuO. We discover
that the phonon softening wavevector associated with CDW correlations becomes
temperature dependent in the high-temperature precursor phase and changes from
a wavevector of 0.238 reciprocal space units (r.l.u.) below the ordering
transition temperature up to 0.3~r.l.u. at 300~K. This high-temperature
behavior shows that "214"-type cuprates can host CDW correlations at a similar
wavevector to previously reported CDW correlations in non-"214"-type cuprates
such as YBaCuO. This indicates that cuprate CDWs may
arise from the same underlying instability despite their apparently different
low temperature ordering wavevectors.Comment: Accepted in Phys. Rev. X; 9 pages; 5 figures; 3 pages of
supplementary materia
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The cumulative effects of known susceptibility variants to predict primary biliary cirrhosis risk.
Multiple genetic variants influence the risk for development of primary biliary cirrhosis (PBC). To explore the cumulative effects of known susceptibility loci on risk, we utilized a weighted genetic risk score (wGRS) to evaluate whether genetic information can predict susceptibility. The wGRS was created using 26 known susceptibility loci and investigated in 1840 UK PBC and 5164 controls. Our data indicate that the wGRS was significantly different between PBC and controls (P=1.61E-142). Moreover, we assessed predictive performance of wGRS on disease status by calculating the area under the receiver operator characteristic curve. The area under curve for the purely genetic model was 0.72 and for gender plus genetic model was 0.82, with confidence limits substantially above random predictions. The risk of PBC using logistic regression was estimated after dividing individuals into quartiles. Individuals in the highest disclosed risk group demonstrated a substantially increased risk for PBC compared with the lowest risk group (odds ratio: 9.3, P=1.91E-084). Finally, we validated our findings in an analysis of an Italian PBC cohort. Our data suggested that the wGRS, utilizing genetic variants, was significantly associated with increased risk for PBC with consistent discriminant ability. Our study is a first step toward risk prediction for PBC
Local stabilisation of polar order at charged antiphase boundaries in antiferroelectric (Bi<sub>0.85</sub>Nd<sub>0.15</sub>)(Ti<sub>0.1</sub>Fe<sub>0.9</sub>)O<sub>3</sub>
Observation of an unusual, negatively-charged antiphase boundary in (Bi<sub>0.85</sub>Nd<sub>0.15</sub>)(Ti<sub>0.1</sub>Fe<sub>0.9</sub>)O<sub>3</sub> is reported. Aberration corrected scanning transmission electron microscopy is used to establish the full three dimensional structure of this boundary including O-ion positions to ~ ± 10 pm. The charged antiphase boundary stabilises tetragonally distorted regions with a strong polar ordering to either side of the boundary, with a characteristic length scale determined by the excess charge trapped at the boundary. Far away from the boundary the crystal relaxes into the well-known Nd-stabilised antiferroelectric phase
The Measure for the Multiverse and the Probability for Inflation
We investigate the measure problem in the framework of inflationary
cosmology. The measure of the history space is constructed and applied to
inflation models. Using this measure, it is shown that the probability for the
generalized single field slow roll inflation to last for e-folds is
suppressed by a factor , and the probability for the generalized
-field slow roll inflation is suppressed by a much larger factor
. Some non-inflationary models such as the cyclic model do not
suffer from this difficulty.Comment: 16 page
Effects of Sand Addition to Heavy Saline-Alkali Soil on the Infiltration and Salt Leaching in Hetao Irrigation District, China
Proceeding PaperSoil salinity is a matter of great economic and environmental implications. In Hetao
Irrigation District, soil salinity limits crop productivity affecting about 69% of its total cultivated
land due to natural soil salinisation and salt accumulation caused by irrigation. The goal of this
study is to contribute to the alleviation of this problem through the technique of adding wind-sand to
the top layer of heavy saline-alkali soil, and to evaluate and analyse their effects on the infiltration
and salt leaching. The experiment was carried out on a laboratory scale. Clayey soil with 21 g/kg
of salts collected at the Ulat Front Banner site was used. Wind-sand was added to the top 30 cm
layer of this soil. The infiltration tests were carried out in plastic columns with 9 cm diameter and
45 cm high, loaded with a soil and wind-sand mixture (from 2% to 30% ratio), supplied by a constant
hydraulic head. Soil water samples were collected for 15 days for quantification of the soil salt
leaching. A significant increase of the infiltration rate was observed in the first infiltration hour, rising
from 1 to 9 mm/h, in response to the addition of 8% and 30% of sandy particles, respectively. The
effects of wind-sand in salt leaching were relevant in the top 20 cm layer. After 7 days of infiltration
there was a decrease in the salt content in soils with 4%, 8%, and 30% of sand particles added, of 35%,
55%, and 95%, respectively, in relation to the control. In conclusion, the practice of adding sandy
particles to the topsoil is a soil melioration method that allows a positive impact on soil infiltration
and salt leaching. An addition of 8% of sand seems to be a good choice, as it favours an increase in
salt leaching of about 55% after 7 days. These results are encouraging and appeal to field studies
to assess the impact on a field-scale system, and the effects of this soil melioration on irrigation,
drainage, and agronomic aspectsinfo:eu-repo/semantics/publishedVersio
On geometric problems related to Brown-York and Liu-Yau quasilocal mass
We discuss some geometric problems related to the definitions of quasilocal
mass proposed by Brown-York \cite{BYmass1} \cite{BYmass2} and Liu-Yau
\cite{LY1} \cite{LY2}. Our discussion consists of three parts. In the first
part, we propose a new variational problem on compact manifolds with boundary,
which is motivated by the study of Brown-York mass. We prove that critical
points of this variation problem are exactly static metrics. In the second
part, we derive a derivative formula for the Brown-York mass of a smooth family
of closed 2 dimensional surfaces evolving in an ambient three dimensional
manifold. As an interesting by-product, we are able to write the ADM mass
\cite{ADM61} of an asymptotically flat 3-manifold as the sum of the Brown-York
mass of a coordinate sphere and an integral of the scalar curvature plus
a geometrically constructed function in the asymptotic region outside
. In the third part, we prove that for any closed, spacelike, 2-surface
in the Minkowski space for which the Liu-Yau mass is
defined, if bounds a compact spacelike hypersurface in ,
then the Liu-Yau mass of is strictly positive unless lies on
a hyperplane. We also show that the examples given by \'{O} Murchadha, Szabados
and Tod \cite{MST} are special cases of this result.Comment: 28 page
On the global well-posedness of a class of Boussinesq- Navier-Stokes systems
In this paper we consider the following 2D Boussinesq-Navier-Stokes systems
\partial_{t}u+u\cdot\nabla u+\nabla p+ |D|^{\alpha}u &= \theta e_{2}
\partial_{t}\theta+u\cdot\nabla \theta+ |D|^{\beta}\theta &=0 \quad with
and . When , , where is an explicit function
as a technical bound, we prove global well-posedness results for rough initial
data.Comment: 23page
A Weak Gravity Conjecture for Scalar Field Theories
We show that the recently proposed weak gravity conjecture\cite{AMNV0601} can
be extended to a class of scalar field theories. Taking gravity into account,
we find an upper bound on the gravity interaction strength, expressed in terms
of scalar coupling parameters. This conjecture is supported by some
two-dimensional models and noncommutative field theories.Comment: version published in JHE
Bibliometric Analysis of the Top-100 Cited Articles on Postoperative Delirium
Qingyuan Miao,* Rui Zhou,* Xinyang Li, Lize Xiong Shanghai Key Laboratory of Anesthesiology and Brain Functional Modulation, Clinical Research Center for Anesthesiology and Perioperative Medicine, Translational Research Institute of Brain and Brain-Like Intelligence, Department of Anesthesiology and Perioperative Medicine, Shanghai Fourth People’s Hospital, School of Medicine, Tongji University, Shanghai City, People’s Republic of China*These authors contributed equally to this workCorrespondence: Lize Xiong, Department of Anesthesiology and Perioperative Medicine, Shanghai Fourth People’s Hospital, No. 1279, Sanmen Road, Shanghai, 200434, People’s Republic of China, Tel +86-21-55603002, Fax +86-21-56660851, Email [email protected]; [email protected]: Postoperative delirium (POD), a common complication affecting short- and long-term prognosis in elderly patients, leads to a heavy burden on social economy and health care. The main purpose of this study is to conduct a bibliometric analysis of the 100 most frequently cited articles on POD.Methods: “Postoperative delirium” and its synonyms were searched in the Web of Science (WoS) core database. The top-100 cited articles were automatically selected by sorting the records in descending order. Key information such as author, journal, article type, publication year, citations, since 2013 usage count, institution, country, and keywords were extracted and analyzed. VOSviewer software was applied to do the visualization analyses of institution co-operation, author interaction, author co-citation, and keywords co-occurrence. The CiteSpace software was used to analyze keywords burst.Results: Most articles were published by authors and institutions in the United States of America (USA). Inouye was the most influential author of this field. The journals that recorded these articles had a high impact factor (IF), with a highest IF of 168.9 and an average IF of 18.04. Cohort studies were the main document type in this field (42 publications), followed by randomized controlled trial (RCT) and systematic reviews or meta-analysis (18 and 14, respectively). The 10 keywords with the highest appearance were “delirium”, “risk-factors”, “surgery”, “confusion assessment method”, “elderly patients”, “hip fracture”, “intensive care unit”, “cardiac surgery”, “general anesthesia”, and “risk”. Moreover, “double blind” and “cardiac surgery” were the most recent booming keywords.Conclusion: We indicated the current research status and tendency of POD by analyzing the 100 most influential articles on POD. The USA is the leader in this field. Prospective study is the preference for authors to cite. Cardiac surgery remains the primary research carrier and the hotspots in the near future may be double-blind studies.Keywords: bibliometric analysis, postoperative delirium, psychiatry, postoperative cognitive disorder, top-10
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