560 research outputs found
Quantum transport thermometry for electrons in graphene
We propose a method of measuring the electron temperature in mesoscopic
conductors and demonstrate experimentally its applicability to micron-size
graphene devices in the linear-response regime (, the bath
temperature). The method can be {especially useful} in case of overheating,
. It is based on analysis of the correlation function of mesoscopic
conductance fluctuations. Although the fluctuation amplitude strongly depends
on the details of electron scattering in graphene, we show that extracted
from the correlation function is insensitive to these details.Comment: 4 pages, 4 figures; final version, as publishe
Dirac fermions in a power-law-correlated random vector potential
We study localization properties of two-dimensional Dirac fermions subject to
a power-law-correlated random vector potential describing, e.g., the effect of
"ripples" in graphene. By using a variety of techniques (low-order perturbation
theory, self-consistent Born approximation, replicas, and supersymmetry) we
make a case for a possible complete localization of all the electronic states
and compute the density of states.Comment: Latex, 4+ page
Search for the edge-on galaxies using an artificial neural network
We present an application of an artificial neural network methodology to a
modern wide-field sky survey Pan-STARRS1 in order to build a high-quality
sample of disk galaxies visible in edge-on orientation. Such galaxies play an
important role in the study of the vertical distribution of stars, gas and
dust, which is usually not available to study in other galaxies outside the
Milky Way. We give a detailed description of the network architecture and the
learning process. The method demonstrates good effectiveness with detection
rate about 97\% and it works equally well for galaxies over a wide range of
brightnesses and sizes, which resulted in a creation of a catalogue of edge-on
galaxies with of objects. The catalogue is published on-line with an
open access.Comment: 15 pages, 11 figure
Observation of dipole-mode vector solitons
We report on the first experimental observation of a novel type of optical
vector soliton, a {\em dipole-mode soliton}, recently predicted theoretically.
We show that these vector solitons can be generated in a photorefractive medium
employing two different processes: a phase imprinting, and a symmetry-breaking
instability of a vortex-mode vector soliton. The experimental results display
remarkable agreement with the theory, and confirm the robust nature of these
radially asymmetric two-component solitary waves.Comment: 4 pages, 8 figures; pictures in the PRL version are better qualit
Partially incoherent optical vortices in self-focusing nonlinear media
We observe stable propagation of spatially localized single- and
double-charge optical vortices in a self-focusing nonlinear medium. The
vortices are created by self-trapping of partially incoherent light carrying a
phase dislocation, and they are stabilized when the spatial incoherence of
light exceeds a certain threshold. We confirm the vortex stabilization effect
by numerical simulations and also show that the similar mechanism of
stabilization applies to higher-order vortices.Comment: 4 pages and 6 figures (including 3 experimental figures
Predictors of effectiveness of glucagon-like peptide-1 receptor agonist therapy in patients with type 2 diabetes and obesity
Background: Type 2 diabetes mellitus (DM2), which mainly develops from visceral obesity, is a socially significant disease. Reduction of losses from DM2 is a priority in modern medicine development. Glucagon-like peptide-1 receptor agonists (aGLP-1) present one of few groups of antidiabetic drugs that allows to reduce not only glycemia, but also weight in DM2. Taking into account predictors of response to the therapy will allow to reach trearment targets with the highest probability, maintaining a safety of treatment, to optimize recommendations for administration of aGPP-1 as much as possible. Aims: To assess dynamics of metabolic parameters, to identify predictors of reduction in blood glucose, body weight and other metabolic parameters on aGLP-1 therapy in patients with DM2 with body mass index (BMI) ≥35 kg/m2. Materials and methods: The study involved 33 patients (10 men, 23 women), who had been treated with aGLP-1, the observation period for 24 weeks was planned. 3 patients terminated the participation before the appointed time (1 – due to pancreatitis development 2 – due to the lack of financial opportunity to purchase the drug). So, 30 patients (10 men, 20 women) were included in the final analysis. Examination consisted of the survey, physical examination with measurement of anthropometric, clinical parameters, filling questionnaires. Data were evaluated at baseline and after 24 weeks of treatment. Results: The study found that patients who achieved weight loss ≥ 5% initially had higher BMI (p = 0.028), lower GLP-1 (p = 0.036), had lower level of ghrelin after standard breakfast test (p = 0.022). There was trend (p = 0.071) to greater decrease in BMI in patients with restrictive type of eating behavior compared to patients who had a mixed type. More pronounced decrease in glycemia was noted in patients who had higher fasting plasma glucose level at inclusion (p = 0.001). Dynamics of HbA1c was better in patients with initially higher GLP-1 (p = 0.016) and higher levels of glycemia (p = 0.001). Also, we revealed the statistically significant decrease in triglycerides level, blood pressure by end of the treatment period. Conclusions: Results indicate the different predictors for reduction in weight, glycemia and blood pressure on aGLP-1 therapy. In addition to the metabolic parameters, level of orexigenic and anorexigenic hormones and psycho-social characteristics of patients help to estimate an expected effect of aGLP-1 therapy. When being identifying, the predictors of weight loss and the predictors of carbohydrate metabolism compensation should be studied separately. Identification of response predictors is necessary to optimize indications for this group of drugs administration in DM2
Observation of discrete vortex solitons in optically-induced photonic lattices
We report on the frst experimental observation of discrete vortex solitons in
two-dimensional optically-induced photonic lattices. We demonstrate strong
stabilization of an optical vortex by the lattice in a self-focusing nonlinear
medium and study the generation of the discrete vortices from a broad class of
singular beams.Comment: 4pages, 5 colour figures. to appear in PR
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