8,047 research outputs found
Azimuthal and single spin asymmetry in deep-inelastic lepton-nucleon scattering
We derive a general framework for describing semi-inclusive deep-inelastic
lepton-nucleon scattering in terms of the unintegrated parton distributions and
other higher twist parton correlations. Such a framework provides a consistent
approach to the calculation of inclusive and semi-inclusive cross sections
including higher twist effects. As an example, we calculate the azimuthal
asymmetries to the order of 1/Q in semi-inclusive process with transversely
polarized target. A non-vanishing single-spin asymmetry in the ``triggered
inclusive process'' is predicted to be 1/Q suppressed with a part of the
coefficient related to a moment of the Sivers function.Comment: 9 pages, 1 figur
Ab-initio density functional studies of stepped TaC surfaces
We report on density functional total energy calculations of the step
formation and interaction energies for vicinal TaC(001) surfaces. Our
calculations show that double and triple-height steps are favored over
single-height steps for a given vicinal orientation, which is in agreement with
recent experimental observations. We provide a description of steps in terms of
atomic displacements and charge localization and predict an experimentally
observable rumpled structure of the step-edges, where the Ta atoms undergo
larger displacements compared to the C atoms.Comment: 4 pages, 4 figure
Correlation effects in the ground state charge density of Mott-insulating NiO: a comparison of ab-initio calculations and high-energy electron diffraction measurements
Accurate high-energy electron diffraction measurements of structure factors
of NiO have been carried out to investigate how strong correlations in the Ni
3d shell affect electron charge density in the interior area of nickel ions and
whether the new ab-initio approaches to the electronic structure of strongly
correlated metal oxides are in accord with experimental observations. The
generalized gradient approximation (GGA) and the local spin density
approximation corrected by the Hubbard U term (LSDA+U) are found to provide the
closest match to experimental measurements. The comparison of calculated and
observed electron charge densities shows that correlations in the Ni 3d shell
suppress covalent bonding between the oxygen and nickel sublattices.Comment: 6 pages, LaTeX and 5 figures in the postscript forma
BDPCA plus LDA : a novel fast feature extraction technique for face recognition
2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe
System Dynamics Model and Simulation of Employee Work-Family Conflict in the Construction Industry.
The construction industry is a demanding work environment where employees' work-family conflict is particularly prominent. This conflict has a significant impact on job and family satisfaction and performance of employees. In order to analyze the dynamic evolution of construction industry employee's work-family conflict between work and family domains, this paper constructs a bi-directional dynamic model framework of work-family conflict by referring to the relevant literature. Consequently, a system dynamics model of employee's work-family conflict in the construction industry is established, and a simulation is conducted. The simulation results indicate that construction industry employees experience work interference with family conflict (WIFC) levels which are significantly greater than the family interference with work conflict (FIWC) levels. This study also revealed that improving work flexibility and organizational support can have a positive impact on the satisfaction and performance of construction industry employees from a work and family perspective. Furthermore, improving family support can only significantly improve employee job satisfaction
Heavy-to-light transition form factors and their relations in light-cone QCD sum rules
The improved light-cone QCD sum rules by using chiral current correlator is
systematically reviewed and applied to the calculation of all the
heavy-to-light form factors, including all the semileptonic and penguin ones.
By choosing suitable chiral currents, the light-cone sum rules for all the form
factors are greatly simplified and depend mainly on one leading twist
distribution amplitude of the light meson. As a result, relations between these
form factors arise naturally. At the considered accuracy these relations
reproduce the results obtained in the literature. Moreover, since the explicit
dependence on the leading twist distribution amplitudes is preserved, these
relations may be more useful to simulate the experimental data and extract the
information on the distribution amplitude.Comment: 1+16 pages, no figure
Quantitative profiling of selective Sox/POU pairing on hundreds of sequences in parallel by Coop-seq
© The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research. Cooperative binding of transcription factors is known to be important in the regulation of gene expression programs conferring cellular identities. However, current methods to measure cooperativity parameters have been laborious and therefore limited to studying only a few sequence variants at a time. We developed Coop-seq (cooperativity by sequencing) that is capable of efficiently and accurately determining the cooperativity parameters for hundreds of different DNA sequences in a single experiment. We apply Coop-seq to 12 dimer pairs from the Sox and POU families of transcription factors using 324 unique sequences with changed half-site orientation, altered spacing and discrete randomization within the binding elements. The study reveals specific dimerization profiles of different Sox factors with Oct4. By contrast, Oct4 and the three neural class III POU factors Brn2, Brn4 and Oct6 assemble with Sox2 in a surprisingly indistinguishable manner. Two novel half-site configurations can support functional Sox/Oct dimerization in addition to known composite motifs. Moreover, Coop-seq uncovers a nucleotide switch within the POU half-site when spacing is altered, which is mirrored in genomic loci bound by Sox2/Oct4 complexes.Link_to_subscribed_fulltex
A novel role for 14-3-3σ in regulating epithelial cell polarity
The loss of epithelial polarity is thought to play an important role during mammary tumor progression. Using a unique transgenic mouse model of ErbB2-induced mammary tumorigenesis, we demonstrated previously that amplification of ErbB2 is frequently accompanied by loss of the 14-3-3σ gene. Here, we demonstrate that ectopic expression of 14-3-3σ results in restoration of epithelial polarity in ErbB2-transformed mammary tumor cells. We further demonstrate that targeted deletion of 14-3-3σ within primary mammary epithelial cells increases their proliferative capacity and adversely affects their ability to form polarized structures. Finally, we show that 14-3-3σ can specifically form complexes with Par3, a protein that is essential for the maintenance of a polarized epithelial state. Taken together, these observations suggest that 14-3-3σ plays a critical role in retaining epithelial polarity. © 2010 by Cold Spring Harbor Laboratory Press
Suppression of Zeeman gradients by nuclear polarization in double quantum dots
We use electric dipole spin resonance to measure dynamic nuclear polarization
in InAs nanowire quantum dots. The resonance shifts in frequency when the
system transitions between metastable high and low current states, indicating
the presence of nuclear polarization. We propose that the low and the high
current states correspond to different total Zeeman energy gradients between
the two quantum dots. In the low current state, dynamic nuclear polarization
efficiently compensates the Zeeman gradient due to the -factor mismatch,
resulting in a suppressed total Zeeman gradient. We present a theoretical model
of electron-nuclear feedback that demonstrates a fixed point in nuclear
polarization for nearly equal Zeeman splittings in the two dots and predicts a
narrowed hyperfine gradient distribution
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