862 research outputs found
Temperature-Dependent Anomalies in the Structure of the (001) Surface of LiCu2O2
Surface corrugation functions, derived from elastic helium atom scattering
(HAS) diffraction patterns at different temperatures, reveal that the Cu2+ rows
in the (001) surface of LiCu2O2 undergo an outward displacement of about 0.15
{\AA} as the surface was cooled down to 140 K. This is probably the first time
that isolated one-dimensional magnetic ion arrays were realized, which
qualifies the Li1+Cu2+O2-2 surface as a candidate to study one-dimensional
magnetism. The rising Cu2+ rows induce a surface incommensurate structural
transition along the a-direction. Surface equilibrium analysis showed that the
surface Cu2+ ions at bulk-like positions experience a net outward force along
the surface normal which is relieved by the displacement. Temperature-dependent
changes of the surface phonon dispersions obtained with the aid of inelastic
HAS measurements combined with surface lattice dynamical calculations are also
reported.Comment: 4 pages, 7 figure
Vertical Confinement and Evolution of Reentrant Insulating Transition in the Fractional Quantum Hall Regime
We have observed an anomalous shift of the high field reentrant insulating
phases in a two-dimensional electron system (2DES) tightly confined within a
narrow GaAs/AlGaAs quantum well. Instead of the well-known transitions into the
high field insulating states centered around , the 2DES confined
within an 80\AA-wide quantum well exhibits the transition at .
Comparably large quantum lifetime of the 2DES in narrow well discounts the
effect of disorder and points to confinement as the primary driving force
behind the evolution of the reentrant transition.Comment: 5 pages, 4 figure
Differential gene expression profiles in foetal skin of Rex rabbits with different wool density
[EN] This study investigated the mechanisms controlling hair follicle development in the Rex rabbit. The Agilent rabbit gene expression microarray was used to determine differentially expressed genes in Rex rabbit foetuses with different wool densities. The expression patterns of selected differentially-expressed genes were further investigated by quantitative real-time PCR. Compared to low wool density rabbits, 1342 differentially expressed probes were identified in high wool density rabbits, including 950 upregulated probes and 392 downregulated probes. Gene ontology analysis revealed that the most upregulated differentially expressed probes belonged to receptors and the most downregulated differentially expressed probes belonged to DNA binding molecules. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that the differentially expressed probes were mainly involved in the sonic hedgehog (Shh) and Eph signalling pathways. The results also suggest that transforming growth factor-beta 1, growth hormone receptor, and the keratin-associated protein 6.1 genes, as well as the Shh and Eph signalling pathways, may be involved in the regulation of hair follicle developmental in Rex rabbits.The authors thank Ms. Libo Huang for her technical assistance. This study was supported by grants from the
Modern Agro-industry Technology Research System (CARS-44-B-1), the Postdoctoral Science Foundation of China (2015M580601)
and Agricultural Major Application Technology Innovation Project of Shandong Province (2015-2016),Liu, L.; Li, B.; Zhu, Y.; Wang, C.; Li, F. (2016). Differential gene expression profiles in foetal skin of Rex rabbits with different wool density. World Rabbit Science. 24(3):223-231. https://doi.org/10.4995/wrs.2016.2335SWORD22323124
Striped antiferromagnetic order and electronic properties of stoichiometric LiFeAs from first-principles calculations
We investigate the structural, electronic, and magnetic properties of
stoichiometric LiFeAs by using state-of-the-arts first-principles method. We
find the magnetic ground-state by comparing the total energies among all the
possible magnetic orders. Our calculated internal positions of Li and As are in
good agreement with experiment. Our results show that stoichiometric LiFeAs has
almost the same striped antiferromagnetic spin order as other FeAs-based parent
compounds and tetragonal FeSe do, and the experimental fact that no magnetic
phase transition has been observed at finite temperature is attributed to the
tiny inter-layer spin coupling
Parity-violating neutron spin rotation in hydrogen and deuterium
We calculate the (parity-violating) spin rotation angle of a polarized
neutron beam through hydrogen and deuterium targets, using pionless effective
field theory up to next-to-leading order. Our result is part of a program to
obtain the five leading independent low-energy parameters that characterize
hadronic parity-violation from few-body observables in one systematic and
consistent framework. The two spin-rotation angles provide independent
constraints on these parameters. Using naive dimensional analysis to estimate
the typical size of the couplings, we expect the signal for standard target
densities to be 10^-7 to 10^-6 rad/m for both hydrogen and deuterium targets.
We find no indication that the nd observable is enhanced compared to the np
one. All results are properly renormalized. An estimate of the numerical and
systematic uncertainties of our calculations indicates excellent convergence.
An appendix contains the relevant partial-wave projectors of the three-nucleon
system.Comment: 44 pages, 17 figures; minor corrections; to be published in EPJ
Measurements of the observed cross sections for exclusive light hadrons containing at , 3.650 and 3.6648 GeV
By analyzing the data sets of 17.3, 6.5 and 1.0 pb taken,
respectively, at , 3.650 and 3.6648 GeV with the BES-II
detector at the BEPC collider, we measure the observed cross sections for
, , ,
and at the three energy
points. Based on these cross sections we set the upper limits on the observed
cross sections and the branching fractions for decay into these
final states at 90% C.L..Comment: 7 pages, 2 figure
Partial wave analysis of J/\psi \to \gamma \phi \phi
Using events collected in the BESII detector, the
radiative decay is
studied. The invariant mass distribution exhibits a near-threshold
enhancement that peaks around 2.24 GeV/.
A partial wave analysis shows that the structure is dominated by a
state () with a mass of
GeV/ and a width of GeV/. The
product branching fraction is: .Comment: 11 pages, 4 figures. corrected proof for journa
Direct Measurements of Absolute Branching Fractions for D0 and D+ Inclusive Semimuonic Decays
By analyzing about 33 data sample collected at and around 3.773
GeV with the BES-II detector at the BEPC collider, we directly measure the
branching fractions for the neutral and charged inclusive semimuonic decays
to be and , and determine the ratio of the two branching
fractions to be
Search for the Rare Decays J/Psi --> Ds- e+ nu_e, J/Psi --> D- e+ nu_e, and J/Psi --> D0bar e+ e-
We report on a search for the decays J/Psi --> Ds- e+ nu_e + c.c., J/Psi -->
D- e+ nu_e + c.c., and J/Psi --> D0bar e+ e- + c.c. in a sample of 5.8 * 10^7
J/Psi events collected with the BESII detector at the BEPC. No excess of signal
above background is observed, and 90% confidence level upper limits on the
branching fractions are set: B(J/Psi --> Ds- e+ nu_e + c.c.)<4.8*10^-5, B(J/Psi
--> D- e+ nu_e + c.c.) D0bar e+ e- + c.c.)<1.1*10^-5Comment: 10 pages, 4 figure
Parity nonconserving cold neutron-parahydrogen interactions
Three pion dominated observables of the parity nonconserving interactions
between the cold neutrons and parahydrogen are calculated. The transversely
polarized neutron spin rotation, unpolarized neutron longitudinal polarization,
and photon-asymmetry of the radiative polarized neutron capture are considered.
For the numerical evaluation of the observables, the strong interactions are
taken into account by the Reid93 potential and the parity nonconserving
interactions by the DDH model along with the two-pion exchange.Comment: 17 pages, 2 figure
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