765 research outputs found
Global properties of Stochastic Loewner evolution driven by Levy processes
Standard Schramm-Loewner evolution (SLE) is driven by a continuous Brownian
motion which then produces a trace, a continuous fractal curve connecting the
singular points of the motion. If jumps are added to the driving function, the
trace branches. In a recent publication [1] we introduced a generalized SLE
driven by a superposition of a Brownian motion and a fractal set of jumps
(technically a stable L\'evy process). We then discussed the small-scale
properties of the resulting L\'evy-SLE growth process. Here we discuss the same
model, but focus on the global scaling behavior which ensues as time goes to
infinity. This limiting behavior is independent of the Brownian forcing and
depends upon only a single parameter, , which defines the shape of the
stable L\'evy distribution. We learn about this behavior by studying a
Fokker-Planck equation which gives the probability distribution for endpoints
of the trace as a function of time. As in the short-time case previously
studied, we observe that the properties of this growth process change
qualitatively and singularly at . We show both analytically and
numerically that the growth continues indefinitely in the vertical direction
for , goes as for , and saturates for . The probability density has two different scales corresponding to
directions along and perpendicular to the boundary. In the former case, the
characteristic scale is . In the latter case the scale
is for , and
for . Scaling functions for the probability density are given for
various limiting cases.Comment: Published versio
PAS-positive lymphocyte vacuoles can be used as diagnostic screening test for Pompe disease
Screening of blood films for the presence of periodic acid-Schiff (PAS)-positive lymphocyte vacuoles is sometimes used to support the diagnosis of Pompe disease, but the actual diagnostic value is still unknown. We collected peripheral blood films from 65 untreated Pompe patients and 51 controls. Lymphocyte vacuolization was quantified using three methods: percentage vacuolated lymphocytes, percentage PAS-positive lymphocytes, and a PAS score depending on staining intensity. Diagnostic accuracy of the tests was assessed using receiver operating characteristic (ROC) curves. All three methods fully discerned classic infantile patients from controls. The mean values of patients with milder forms of Pompe disease were significantly higher than those of controls, but full separation was not obtained. The area under the ROC curve was 0.98 for the percentage vacuolated lymphocytes (optimal cutoff value 3; sensitivity 91%, specificity 96%) and 0.99 for the percentage PAS-positive lymphocytes and PAS score (optimal cutoff value 9; sensitivity 100%, specificity 98%). Our data indicate that PAS-stained blood films can be used as a reliable screening tool to support a diagnosis of Pompe disease. The percentage of PAS-positive lymphocytes is convenient for use in clinical practice but should always be interpreted in combination with other clinical and laboratory parameters
The Close AGN Reference Survey (CARS): Tracing the circumnuclear star formation in the super-Eddington NLS1 Mrk 1044
The host galaxy conditions for rapid supermassive black hole growth are
poorly understood. Narrow-line Seyfert 1 (NLS1) galaxies often exhibit high
accretion rates and are hypothesized to be prototypes of active galactic nuclei
(AGN) at an early stage of their evolution. We present VLT MUSE NFM-AO
observations of Mrk 1044, the nearest super-Eddington accreting NLS1. Together
with archival MUSE WFM data we aim to understand the host galaxy processes that
drive Mrk 1044's black hole accretion. We extract the faint stellar continuum
emission from the AGN-deblended host and perform spatially resolved emission
line diagnostics with an unprecedented resolution. Combining both MUSE WFM and
NFM-AO observations, we use a kinematic model of a thin rotating disk to trace
the stellar and ionized gas motion from 10kpc down to 30pc around the
nucleus. Mrk 1044's stellar kinematics follow circular rotation, whereas the
ionized gas shows tenuous spiral features in the center. We resolve a compact
star forming circumnuclear ellipse (CNE) that has a semi-minor axis of
306pc. Within this CNE, the gas is metal rich and its line ratios are
entirely consistent with excitation by star formation. With an integrated SFR
of the CNE contributes 27% of
the galaxy-wide star formation. We conclude that Mrk 1044's nuclear activity
has not yet affected the circumnuclear star formation. Thus, Mrk 1044 is
consistent with the idea that NLS1s are young AGN. A simple mass budget
consideration suggests that the circumnuclear star formation and AGN phase are
connected and the patterns in the ionized gas velocity field are a signature of
the ongoing AGN feeding.Comment: accepted for publication in A&A, 17 pages, 14 figures, 1 table, for
Fig. 5 associated animation see https://youtube.com/watch?v=H_WSgWJSCf
A global view on star formation: The GLOSTAR Galactic plane survey. VII. Supernova remnants in the Galactic longitude range
Context. While over 1000 supernova remnants (SNRs) are estimated to exist in
the Milky Way, only less than 400 have been found to date. In the context of
this apparent deficiency, more than 150 SNR candidates were recently identified
in the D-configuration Very Large Array (VLA-D) continuum images of the 4--8
GHz global view on star formation (GLOSTAR) survey, in the Galactic longitude
range . Aims. We attempt to find evidence of nonthermal
synchrotron emission from 35 SNR candidates in the region of Galactic longitude
range , and also to study the radio continuum emission
from the previously confirmed SNRs in this region. Methods. Using the
short-spacing corrected GLOSTAR VLA-D+Effelsberg images, we measure
GHz total and linearly polarized flux densities of the SNR candidates and the
SNRs that were previously confirmed. We also attempt to determine the spectral
indices by measuring flux densities from complementary Galactic plane surveys
and from the temperature-temperature plots of the GLOSTAR-Effelsberg images.
Results. We provide evidence of nonthermal emission from four candidates that
have spectral indices and polarization consistent with a SNR origin, and,
considering their morphology, we are confident that three of these
(G28.36+0.21, G28.78-0.44, and G29.38+0.10) are indeed SNRs. However, about
of the candidates have spectral index measurements that indicate thermal
emission, and the rest of them are too faint to have a good constraint on the
spectral index yet. Conclusions. Additional observations at longer wavelengths
and higher sensitivities will shed more light on the nature of these
candidates. A simple Monte-Carlo simulation reiterates the view that future
studies must persist with the current strategy of searching for SNRs with small
angular size to solve the problem of the Milky Way's missing SNRs.Comment: To be published in A&A. 21 pages, 15 figure
- …