1,274 research outputs found
Enhanced Orbital Degeneracy in Momentum Space for LaOFeAs
The Fermi surfaces (FS) of LaOFeAs (in =0 plane) consist of two
hole-type circles around point, which do not touch each other, and two
electron-type co-centered ellipses around M point, which are degenerate along
the M-X line. By first-principles calculations, here we show that additional
degeneracy exists for the two electron-type FS, and the crucial role of
F-doping and pressure is to enhance this orbital degeneracy. It is suggested
that the inter-orbital fluctuation is the key point to understand the
unconventional superconductivity in these materials.Comment: 4 pages, 5 figure
Square patterns in Rayleigh-Benard convection with rotation about a vertical axis
We present experimental results for Rayleigh-Benard convection with rotation
about a vertical axis at dimensionless rotation rates in the range 0 to 250 and
upto 20% above the onset. Critical Rayleigh numbers and wavenumbers agree with
predictions of linear stability analysis. For rotation rates greater than 70
and close to onset, the patterns are cellular with local four-fold coordination
and differ from the theoretically expected Kuppers-Lortz unstable state. Stable
as well as intermittent defect-free square lattices exist over certain
parameter ranges. Over other ranges defects dynamically disrupt the lattice but
cellular flow and local four-fold coordination is maintained.Comment: ReVTeX, 4 pages, 7 eps figures include
First Principles Studies on 3-Dimentional Strong Topological Insulators: Bi2Te3, Bi2Se3 and Sb2Te3
Bi2Se3, Bi2Te3 and Sb2Te3 compounds are recently predicted to be
3-dimentional (3D) strong topological insulators. In this paper, based on
ab-initio calculations, we study in detail the topological nature and the
surface states of this family compounds. The penetration depth and the
spin-resolved Fermi surfaces of the surface states will be analyzed. We will
also present an procedure, from which highly accurate effective Hamiltonian can
be constructed, based on projected atomic Wannier functions (which keep the
symmetries of the systems). Such Hamiltonian can be used to study the
semi-infinite systems or slab type supercells efficiently. Finally, we discuss
the 3D topological phase transition in Sb2(Te1-xSex)3 alloy system.Comment: 8 pages,17 figure
Temporal Profiling of the Secretome during Adipogenesis in Humans
Adipose tissue plays a key role as a fat-storage depot and as an endocrine organ. Although mouse adipogenesis has been studied extensively, limited studies have been conducted to characterize this process in humans. We carried out a temporal proteomic analysis to interrogate the dynamic changes in the secretome of primary human preadipocytes as they differentiate into mature adipocytes. Using iTRAQ-based quantitative proteomics, we identified and quantified 420 proteins from the secretome of differentiated human adipocytes. Our results revealed that the majority of proteins showed differential expression during the course of differentiation. In addition to adipokines known to be differentially secreted in the course of adipocyte differentiation, we identified a number of proteins whose dynamic expression in this process has not been previously documented. They include collagen triple helix repeat containing 1, cytokine receptor-like factor 1, glypican-1, hepatoma-derived growth factor, SPARC related modular calcium binding protein 1, SPOCK 1, and sushi repeat-containing protein. A bioinformatics analysis using Human Protein Reference Database and Human Proteinpedia revealed that of the 420 proteins identified, 164 proteins possess signal peptides and 148 proteins are localized to the extracellular compartment. Additionally, we employed antibody arrays to quantify changes in the levels of 182 adipokines during human adipogenesis. This is the first large-scale quantitative proteomic stud
Statefinder diagnostic for cosmology with the abnormally weighting energy hypothesis
In this paper, we apply the statefinder diagnostic to the cosmology with the
Abnormally Weighting Energy hypothesis (AWE cosmology), in which dark energy in
the observational (ordinary matter) frame results from the violation of weak
equivalence principle (WEP) by pressureless matter. It is found that there
exist closed loops in the statefinder plane, which is an interesting
characteristic of the evolution trajectories of statefinder parameters and can
be used to distinguish AWE cosmology from the other cosmological models.Comment: 5 pages, 4 figures, accepted by PR
Effects of dimers on cooperation in the spatial prisoner's dilemma game
We investigate the evolutionary prisoner's dilemma game in structured
populations by introducing dimers, which are defined as that two players in
each dimer always hold a same strategy. We find that influences of dimers on
cooperation depend on the type of dimers and the population structure. For
those dimers in which players interact with each other, the cooperation level
increases with the number of dimers though the cooperation improvement level
depends on the type of network structures. On the other hand, the dimers, in
which there are not mutual interactions, will not do any good to the
cooperation level in a single community, but interestingly, will improve the
cooperation level in a population with two communities. We explore the
relationship between dimers and self-interactions and find that the effects of
dimers are similar to that of self-interactions. Also, we find that the dimers,
which are established over two communities in a multi-community network, act as
one type of interaction through which information between communities is
communicated by the requirement that two players in a dimer hold a same
strategy.Comment: 12 pages and 3 figure
Probing the isospin dependent mean field and nucleon nucleon cross section in the medium by the nucleon emissions
We study the isospin effects of the mean field and two-body collision on the
nucleon emissions at the intermediate energy heavy ion collisions by using an
isospin dependent transport theory. The calculated results show that the
nucleon emission number depends sensitively the isospin effect of
nucleon nucleon cross section and weakly on the isospin dependent mean field
for neutron-poor system in higher beam energy region . In particular, the
correlation between the medium correction of two-body collision and the
momentum dependent interaction enhances the dependence of nucleon emission
number on the isospin effect of nucleon nucleon cross section.
On the contrary, the ratio of the neutron proton ratio of the gas phase to
the neutron proton ratio of the liquid phase, i.e., the degree of isospin
fractionation depends sensitively on the
isospin dependent mean field and weakly on the isospin effect of two-body
collision for neutron-rich system in the lower beam energy region. In this
case, and are the probes for
extracting the information about the isospin dependent nucleon nucleon cross
section in the medium and the isospin dependent mean field,respectively.Comment: 4 pages,4 figure
Drinfeld twist and symmetric Bethe vectors of the open XYZ chain with non-diagonal boundary terms
With the help of the Drinfeld twist or factorizing F-matrix for the
eight-vertex solid-on-solid (SOS) model, we find that in the F-basis provided
by the twist the two sets of pseudo-particle creation operators simultaneously
take completely symmetric and polarization free form. This allows us to obtain
the explicit and completely symmetric expressions of the two sets of Bethe
states of the model.Comment: Latex file, 25 page
Disrupted neural variability during propofolāinduced sedation and unconsciousness
Variability quenching is a widespread neural phenomenon in which trialātoātrial variability (TTV) of neural activity is reduced by repeated presentations of a sensory stimulus. However, its neural mechanism and functional significance remain poorly understood. Recurrent network dynamics are suggested as a candidate mechanism of TTV, and they play a key role in consciousness. We thus asked whether the variabilityāquenching phenomenon is related to the level of consciousness. We hypothesized that TTV reduction would be compromised during reduced level of consciousness by propofol anesthetics. We recorded functional magnetic resonance imaging signals of restingāstate and stimulusāinduced activities in three conditions: wakefulness, sedation, and unconsciousness (i.e., deep anesthesia). We measured the average (trialātoātrial mean, TTM) and variability (TTV) of auditory stimulusāinduced activity under the three conditions. We also examined another form of neural variability (temporal variability, TV), which quantifies the overall dynamic range of ongoing neural activity across time, during both the restingāstate and the task. We found that (a) TTM deceased gradually from wakefulness through sedation to anesthesia, (b) stimulusāinduced TTV reduction normally seen during wakefulness was abolished during both sedation and anesthesia, and (c) TV increased in the task state as compared to restingāstate during both wakefulness and sedation, but not anesthesia. Together, our results reveal distinct effects of propofol on the two forms of neural variability (TTV and TV). They imply that the anesthetic disrupts recurrent network dynamics, thus prevents the stabilization of cortical activity states. These findings shed new light on the temporal dynamics of neuronal variability and its alteration during anestheticāinduced unconsciousness.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146388/1/hbm24304_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146388/2/hbm24304.pd
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