4,488 research outputs found
Quantum confinement in perovskite oxide heterostructures: tight binding instead of nearly free electron picture
Most recently, orbital-selective quantum well states of electrons have
been experimentally observed in SrVO ultrathin films [K. Yoshimatsu et.
al., Science 333, 319 (2011)] and SrTiO surfaces [A. F. Santander-Syro et.
al., Nature 469, 189 (2011)]. Hitherto, one tries to explain these experiments
by a nearly free electron (NFE) model, an approach widely used for delocalized
electrons in semiconductor heterostructures and simple metal films. We show
that a tight binding (TB) model is more suitable for describing
heterostructures with more localized electrons. In this paper, we construct
from first principles simple TB models for perovskite oxide heterostructures
and surfaces. We show that the TB model provides a simple intuitive physical
picture and yields, already with only two parameters, quantitatively much more
reliable results, consistent with experiment
The Expanding Landscape of Alternative Splicing Variation in Human Populations.
Alternative splicing is a tightly regulated biological process by which the number of gene products for any given gene can be greatly expanded. Genomic variants in splicing regulatory sequences can disrupt splicing and cause disease. Recent developments in sequencing technologies and computational biology have allowed researchers to investigate alternative splicing at an unprecedented scale and resolution. Population-scale transcriptome studies have revealed many naturally occurring genetic variants that modulate alternative splicing and consequently influence phenotypic variability and disease susceptibility in human populations. Innovations in experimental and computational tools such as massively parallel reporter assays and deep learning have enabled the rapid screening of genomic variants for their causal impacts on splicing. In this review, we describe technological advances that have greatly increased the speed and scale at which discoveries are made about the genetic variation of alternative splicing. We summarize major findings from population transcriptomic studies of alternative splicing and discuss the implications of these findings for human genetics and medicine
M\"ossbauer spectroscopy study of magnetic fluctuations in superconducting RbGdFeAsO
Fe M\"ossbauer spectra were measured at different temperatures between
5.9 K and 300 K on the recently discovered self-doped superconducting
RbGdFeAsO with T as high as 35 K. Singlet pattern was
observed down to the lowest temperature measured in this work, indicating the
absence of static magnetic order on the Fe site. The intermediate isomer shift
in comparison with that of the samples RbFeAs and GdFeAsO confirms the
self doping induced local electronic structure change. Surprisingly, we observe
two magnetic fluctuation induced spectral broadenings below 15 K and
100 K which are believed to be originated from the transferred magnetic
fluctuations of the Gd moments and that of the magnetic fluctuations of
the Fe atoms, respectively.Comment: 6 pages, 6 figures, 1 tabl
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