3,052 research outputs found
A caricature of a singular curvature flow in the plane
We study a singular parabolic equation of the total variation type in one
dimension. The problem is a simplification of the singular curvature flow. We
show existence and uniqueness of weak solutions. We also prove existence of
weak solutions to the semi-discretization of the problem as well as convergence
of the approximating sequences. The semi-discretization shows that facets must
form. For a class of initial data we are able to study in details the facet
formation and interactions and their asymptotic behavior. We notice that our
qualitative results may be interpreted with the help of a special composition
of multivalued operators
Postoperative hypofractionated radiotherapy of patients with glioblastoma: three courses of irradiation separated by 2 or 4 week intervals. A preliminary report on a randomized trial
Coexistence of opposite opinions in a network with communities
The Majority Rule is applied to a topology that consists of two coupled
random networks, thereby mimicking the modular structure observed in social
networks. We calculate analytically the asymptotic behaviour of the model and
derive a phase diagram that depends on the frequency of random opinion flips
and on the inter-connectivity between the two communities. It is shown that
three regimes may take place: a disordered regime, where no collective
phenomena takes place; a symmetric regime, where the nodes in both communities
reach the same average opinion; an asymmetric regime, where the nodes in each
community reach an opposite average opinion. The transition from the asymmetric
regime to the symmetric regime is shown to be discontinuous.Comment: 14 pages, 4 figure
Magneto-optical Selection Rules in Bilayer Bernal Graphene
The low-frequency magneto-optical properties of bilayer Bernal graphene are
studied by the tight-binding model with four most important interlayer
interactions taken into account. Since the main features of the wave functions
are well depicted, the Landau levels can be divided into two groups based on
the characteristics of the wave functions. These Landau levels lead to four
categories of absorption peaks in the optical absorption spectra. Such
absorption peaks own complex optical selection rules and these rules can be
reasonably explained by the characteristics of the wave functions. In addition,
twin-peak structures, regular frequency-dependent absorption rates and complex
field-dependent frequencies are also obtained in this work. The main features
of the absorption peaks are very different from those in monolayer graphene and
have their origin in the interlayer interactions
MYOD1 involvement in myopathy
[Excerpt] Introduction
Myogenic Differentiation 1 (MYOD1)
encodes a transcription factor that plays
an important role in myogenic determination into mature skeletal muscle [1].
The first loss-of-function mutation of
MYOD1 in humans was described in
three siblings with perinatal lethal fetal
akinesia [2].[...]We thank the individual and family.
Funding was provided by The Fonds de
recherche du Québec - Santé (FRQS) and
Canadian Institutes of Health Research
(CIHR) to P.M.C., Fundação para a
Ciência e Tecnologia (FCT) with the fellowship SFRH/BD/84650/2010 to F.L.
and Groupe Pasteur Mutualité Foundation (GPM Foundation) to M.M.info:eu-repo/semantics/publishedVersio
Strain-induced Evolution of Electronic Band Structures in a Twisted Graphene Bilayer
Here we study the evolution of local electronic properties of a twisted
graphene bilayer induced by a strain and a high curvature. The strain and
curvature strongly affect the local band structures of the twisted graphene
bilayer; the energy difference of the two low-energy van Hove singularities
decreases with increasing the lattice deformations and the states condensed
into well-defined pseudo-Landau levels, which mimic the quantization of massive
Dirac fermions in a magnetic field of about 100 T, along a graphene wrinkle.
The joint effect of strain and out-of-plane distortion in the graphene wrinkle
also results in a valley polarization with a significant gap, i.e., the
eight-fold degenerate Landau level at the charge neutrality point is splitted
into two four-fold degenerate quartets polarized on each layer. These results
suggest that strained graphene bilayer could be an ideal platform to realize
the high-temperature zero-field quantum valley Hall effect.Comment: 4 figure
Statistical Inference for Valued-Edge Networks: Generalized Exponential Random Graph Models
Across the sciences, the statistical analysis of networks is central to the
production of knowledge on relational phenomena. Because of their ability to
model the structural generation of networks, exponential random graph models
are a ubiquitous means of analysis. However, they are limited by an inability
to model networks with valued edges. We solve this problem by introducing a
class of generalized exponential random graph models capable of modeling
networks whose edges are valued, thus greatly expanding the scope of networks
applied researchers can subject to statistical analysis
Two band gap field-dependent thermal conductivity of
The thermal conductivity of the new superconductor was
studied as a function of the temperature and a magnetic field. No anomaly in
the thermal conductivity is observed around the superconducting
transition in absence or presence of magnetic fields up to 14 Tesla; upon that
field the superconductivity of persisted. The thermal conductivity in
zero-field shows a -linear increase up to 50K. The thermal conductivity is
found to increase with increasing field at high fields. We interpret the
findings as if there are two subsystems of quasiparticles with different
field-dependent characters in a two ( and )-band superconductor reacting
differently with the vortex structure. The unusual enhancement of at low temperature but higher than a () critical field
is interpreted as a result of the overlap of the low energy states outside the
vortex cores in the -band.Comment: 6 pages,3 figure
Graphene-based modulation-doped superlattice structures
The electronic transport properties of graphene-based superlattice structures
are investigated. A graphene-based modulation-doped superlattice structure
geometry is proposed and consist of periodically arranged alternate layers:
InAs/graphene/GaAs/graphene/GaSb. Undoped graphene/GaAs/graphene structure
displays relatively high conductance and enhanced mobilities at elevated
temperatures unlike modulation-doped superlattice structure more steady and
less sensitive to temperature and robust electrical tunable control on the
screening length scale. Thermionic current density exhibits enhanced behaviour
due to presence of metallic (graphene) mono-layers in superlattice structure.
The proposed superlattice structure might become of great use for new types of
wide-band energy gap quantum devices.Comment: 5 figure
Light smoking at base-line predicts a higher mortality risk to women than to men; evidence from a cohort with long follow-up
BACKGROUND: There is conflicting evidence as to whether smoking is more harmful to women than to men. The UK Cotton Workers’ Cohort was recruited in the 1960s and contained a high proportion of men and women smokers who were well matched in terms of age, job and length of time in job. The cohort has been followed up for 42 years. METHODS: Mortality in the cohort was analysed using an individual relative survival method and Cox regression. Whether smoking, ascertained at baseline in the 1960s, was more hazardous to women than to men was examined by estimating the relative risk ratio women to men, smokers to never smoked, for light (1–14), medium (15–24), heavy (25+ cigarettes per day) and former smoking. RESULTS: For all-cause mortality relative risk ratios were 1.35 for light smoking at baseline (95% CI 1.07-1.70), 1.15 for medium smoking (95% CI 0.89-1.49) and 1.00 for heavy smoking (95% CI 0.63-1.61). Relative risk ratios for light smoking at baseline for circulatory system disease was 1.42 (95% CI 1.01 to 1.98) and for respiratory disease was 1.89 (95% CI 0.99 to 3.63). Heights of participants provided no explanation for the gender difference. CONCLUSIONS: Light smoking at baseline was shown to be significantly more hazardous to women than to men but the effect decreased as consumption increased indicating a dose response relationship. Heavy smoking was equally hazardous to both genders. This result may help explain the conflicting evidence seen elsewhere. However gender differences in smoking cessation may provide an alternative explanation
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