39 research outputs found
Alternative method to find orbits in chaotic systems
We present here a new method which applies well ordered symbolic dynamics to
find unstable periodic and non-periodic orbits in a chaotic system. The method
is simple and efficient and has been successfully applied to a number of
different systems such as the H\'enon map, disk billiards, stadium billiard,
wedge billiard, diamagnetic Kepler problem, colinear Helium atom and systems
with attracting potentials. The method seems to be better than earlier applied
methods.Comment: 5 pages, uuencoded compressed tar PostScript fil
Occurrence of porcine dermatitis and nephropathy syndrome in Hungary
In the past few years a characteristic, often fatal disease associated with cutaneous lesions and nephropathy has been observed in several large pig herds and household pig stocks of Hungary. In addition to general symptoms and slight fever in several cases, the disease was characterised by cutaneous lesions occurring mostly on the ventral part of the thorax and abdomen, on the extremities and ear pinnae, and in the nasal and perianal region. In the acute phase, circumscribed hyperaemic, confluent, crust-covered areas were seen. Histological examination revealed necrosis of the epithelial layer and lympho-histiocytic vasculitis in the corium, here and there accompanied by thrombosis and fibrinoid degeneration. The kidneys were pale brown and harder to tear, with cortical petechiae in most cases. By histopathological examination, intra- and extracapillary glomerulonephritis accompanied by fibrinoid exudation was seen. Some of the renal tubules were dilated, others were atrophied, and in advanced cases proliferation of the intertubular connective tissue and inflammatory cell infiltration also occurred. Necrotic vasculitis was also observed in some cases. By immunohistochemical examination IgA, IgG and IgM, and in a single case C3 belonging to the complement system were observed in the pathologically changed skin areas and kidneys. By polymerase chain reaction (PCR), porcine circovirus type 2 (PCV-2) was detected. Bacteriological and serological examinations did not reveal infections of aetiological importance
First isolation and characterization of Brucella microti from wild boar
Background:
Brucella microti
was first isolated from common vole (
Microtus arvalis
) in the Czech Republic in Central
Europe in 2007. As
B. microti
is the only
Brucella
species known to live in soil, its distribution, ecology, zoonotic
potential, and genomic organization is of particular interest. The present paper is the first to report the isolation of
B. microti
from a wild boar (
Sus scrofa
), which is also the first isolation of this bacterial species in Hungary.
Results:
The
B. microti
isolate was cultured, after enrichment in
Brucella
-selective broth, from the submandibular
lymph node of a female wild boar that was taken by hunters in Hungary near the Austrian border in September
2014. Histological and immunohistological examinations of the lymph node sections with
B. abortus-
,
B. suis-
and
B. canis
-specific sera gave negative results. The isolate did not require CO
2
for growth, was oxidase, catalase, and
urease positive, H
2
S negative, grew well in the presence of 20
μ
g/ml basic fuchsin and thionin, and had brownish
pigmentation after three days of incubation. It gave strong positive agglutination with anti-A and anti-M but had a
negative reaction with anti-R monospecific sera. The API 20 NE test identified it as
Ochrobactrum anthropi
with
99.9 % identity, and it showed
B. microti
-specific banding pattern in the Bruce- and Suis-ladder multiplex PCR systems.
Whole genome re-sequencing id
entified 30 SNPs in orthologous loci when compared to the
B. microti
reference
genome available in GenBank, and the ML
VA analysis yielded a unique profile.
Conclusions:
Given that the female wild boar did not develop any
clinical disease, we hypothesize that this host
species only harboured the bacterium, serving as a possible reservoir capable of maintaining and spreading this
pathogen. The infectious source could have been either
a rodent, a carcass that had been eaten or infection
occurred via the boar rooting in soil. The low number of discovered SNPs suggests an unexpectedly high level of
genetic homogeneity in this
Brucella
species.
Keywords:
Biochemistry,
Brucella microti
, Immunohistochemistry, MLVA, Morphology, Wild boar, Whole genome
sequencing, Hungary
Chaos in Quantum Dots: Dynamical Modulation of Coulomb Blockade Peak Heights
The electrostatic energy of an additional electron on a conducting grain
blocks the flow of current through the grain, an effect known as the Coulomb
blockade. Current can flow only if two charge states of the grain have the same
energy; in this case the conductance has a peak. In a small grain with
quantized electron states, referred to as a quantum dot, the magnitude of the
conductance peak is directly related to the magnitude of the wavefunction near
the contacts to the dot. Since dots are generally irregular in shape, the
dynamics of the electrons is chaotic, and the characteristics of Coulomb
blockade peaks reflects those of wavefunctions in chaotic systems. Previously,
a statistical theory for the peaks was derived by assuming these wavefunctions
to be completely random. Here we show that the specific internal dynamics of
the dot, even though it is chaotic, modulates the peaks: because all systems
have short-time features, chaos is not equivalent to randomness. Semiclassical
results are derived for both chaotic and integrable dots, which are
surprisingly similar, and compared to numerical calculations. We argue that
this modulation, though unappreciated, has already been seen in experiments.Comment: 4 pages, 3 postscript figs included (2 color), uses epsf.st
Edge Diffraction, Trace Formulae and the Cardioid Billiard
We study the effect of edge diffraction on the semiclassical analysis of two
dimensional quantum systems by deriving a trace formula which incorporates
paths hitting any number of vertices embedded in an arbitrary potential. This
formula is used to study the cardioid billiard, which has a single vertex. The
formula works well for most of the short orbits we analyzed but fails for a few
diffractive orbits due to a breakdown in the formalism for certain geometries.
We extend the symbolic dynamics to account for diffractive orbits and use it to
show that in the presence of parity symmetry the trace formula decomposes in an
elegant manner such that for the cardioid billiard the diffractive orbits have
no effect on the odd spectrum. Including diffractive orbits helps resolve peaks
in the density of even states but does not appear to affect their positions. An
analysis of the level statistics shows no significant difference between
spectra with and without diffraction.Comment: 25 pages, 12 Postscript figures. Published versio
How Chaotic is the Stadium Billiard? A Semiclassical Analysis
The impression gained from the literature published to date is that the
spectrum of the stadium billiard can be adequately described, semiclassically,
by the Gutzwiller periodic orbit trace formula together with a modified
treatment of the marginally stable family of bouncing ball orbits. I show that
this belief is erroneous. The Gutzwiller trace formula is not applicable for
the phase space dynamics near the bouncing ball orbits. Unstable periodic
orbits close to the marginally stable family in phase space cannot be treated
as isolated stationary phase points when approximating the trace of the Green
function. Semiclassical contributions to the trace show an - dependent
transition from hard chaos to integrable behavior for trajectories approaching
the bouncing ball orbits. A whole region in phase space surrounding the
marginal stable family acts, semiclassically, like a stable island with
boundaries being explicitly -dependent. The localized bouncing ball
states found in the billiard derive from this semiclassically stable island.
The bouncing ball orbits themselves, however, do not contribute to individual
eigenvalues in the spectrum. An EBK-like quantization of the regular bouncing
ball eigenstates in the stadium can be derived. The stadium billiard is thus an
ideal model for studying the influence of almost regular dynamics near
marginally stable boundaries on quantum mechanics.Comment: 27 pages, 6 figures, submitted to J. Phys.
Semiclassical Theory of Coulomb Blockade Peak Heights in Chaotic Quantum Dots
We develop a semiclassical theory of Coulomb blockade peak heights in chaotic
quantum dots. Using Berry's conjecture, we calculate the peak height
distributions and the correlation functions. We demonstrate that the
corrections to the corresponding results of the standard statistical theory are
non-universal and can be expressed in terms of the classical periodic orbits of
the dot that are well coupled to the leads. The main effect is an oscillatory
dependence of the peak heights on any parameter which is varied; it is
substantial for both symmetric and asymmetric lead placement. Surprisingly,
these dynamical effects do not influence the full distribution of peak heights,
but are clearly seen in the correlation function or power spectrum. For
non-zero temperature, the correlation function obtained theoretically is in
good agreement with that measured experimentally.Comment: 5 color eps figure
Chlamydophila spp. infection in horses with recurrent airway obstruction: similarities to human chronic obstructive disease
Functional Interaction between Type III-Secreted Protein IncA of Chlamydophila psittaci and Human G3BP1
Chlamydophila (Cp.) psittaci, the causative agent of psittacosis in birds and humans, is the most important zoonotic pathogen of the family Chlamydiaceae. These obligate intracellular bacteria are distinguished by a unique biphasic developmental cycle, which includes proliferation in a membrane-bound compartment termed inclusion. All Chlamydiaceae spp. possess a coding capacity for core components of a Type III secretion apparatus, which mediates specific delivery of anti-host effector proteins either into the chlamydial inclusion membrane or into the cytoplasm of target eukaryotic cells. Here we describe the interaction between Type III-secreted protein IncA of Cp. psittaci and host protein G3BP1 in a yeast two-hybrid system. In GST-pull down and co-immunoprecipitation experiments both in vitro and in vivo interaction between full-length IncA and G3BP1 were shown. Using fluorescence microscopy, the localization of G3BP1 near the inclusion membrane of Cp. psittaci-infected Hep-2 cells was demonstrated. Notably, infection of Hep-2 cells with Cp. psittaci and overexpression of IncA in HEK293 cells led to a decrease in c-Myc protein concentration. This effect could be ascribed to the interaction between IncA and G3BP1 since overexpression of an IncA mutant construct disabled to interact with G3BP1 failed to reduce c-Myc concentration. We hypothesize that lowering the host cell c-Myc protein concentration may be part of a strategy employed by Cp. psittaci to avoid apoptosis and scale down host cell proliferation