Complexity and asymptotic stability in the process of biochemical substance exchange
in a coupled ring of cells http://dx.doi.org/10.1016/j.chaos.2014.04.008 by Mihailović, D.T. (Faculty of Agriculture, Division of Meteorology and Biophysics,
University of Novi Sad, Dositeja Obradovica Sq. 8, 21000 Novi Sad (Serbia)); Kostić,
V. (Faculty of Sciences, Department of Mathematics and Informatics, University of
Novi Sad, Dositeja Obradovica Sq. 3, 21000 Novi Sad (Serbia)); Balaž, I. (Faculty
of Sciences, Department of Physics, University of Novi Sad, Dositeja Obradovica Sq.
3, 21000 Novi Sad (Serbia)); Cvetković, Lj. (Faculty of Sciences, Department
of Mathematics and Informatics, University of Novi Sad, Dositeja Obradovica Sq. 3,
21000 Novi Sad (Serbia)), E-mail: guto@polj.uns.ac.rs Read MoreCollapse
[en]
Highlights: • We make a model of biochemical substance exchange in a coupled
ring of cells. • We examined Lempel–Zev complexity of the dynamics of
modeled exchange process. • We have examined asymptotic stability of system
using an eigenvalue-based method. • For weak coupling exists a zone of low complexity
in the space of master parameters. • In chaotic conditions exists a zone of
stability in the space of master parameters. - Abstract: We have considered the complexity
and asymptotic stability in the process of biochemical substance exchange in a coupled
ring of cells. We have used coupled maps to model this process. It includes the coupling
parameter, cell affinity and environmental factor as master parameters of the model.
We have introduced: (i) the Lempel–Ziv complexity spectrum and (ii) the Lempel–Ziv
complexity spectrum highest value to analyze the dynamics of two cell model. The asymptotic
stability of this dynamical system using an eigenvalue-based method has been considered.
Using these complexity measures we have noticed an “island” of low complexity
in the space of the master parameters for the weak coupling. We have explored how
stability of the equilibrium of the biochemical substance exchange in a multi-cell
system (N = 100) is influenced by the changes in the master parameters of the model
for the weak and strong coupling. We have found that in highly chaotic conditions
there exists space of master parameters for which the process of biochemical substance
exchange in a coupled ring of cells is stable$$$$
Linear correlation between fractal dimension of surface EMG signal from Rectus Femoris
and height of vertical jump http://dx.doi.org/10.1016/j.chaos.2014.06.004 by Ancillao, Andrea (IRCCS “San Raffaele Pisana”, San Raffaele SPA, via della
Pisana 235, 00163 Roma (Italy)); Galli, Manuela (Department of Electronic, Information
and Bioengineering, Politecnico di Milano, p.zza Leonardo Da Vinci 32, 20133 Milano
(Italy); IRCCS “San Raffaele Pisana”, San Raffaele SPA, via della Pisana
235, 00163 Roma (Italy)); Rigoldi, Chiara (Department of Electronic, Information and
Bioengineering, Politecnico di Milano, p.zza Leonardo Da Vinci 32, 20133 Milano (Italy));
Albertini, Giorgio (IRCCS “San Raffaele Pisana”, San Raffaele SPA, via
della Pisana 235, 00163 Roma (Italy)), E-mail: andrea.ancillao@hotmail.com, E-mail:
manuela.galli@polimi.it, E-mail: chiara.rigoldi@polimi.it, E-mail: giorgio.albertini@sanraffaele.it Read MoreCollapse
[en]
Fractal dimension was demonstrated to be able to characterize the complexity of biological
signals. The EMG time series are well known to have a complex behavior and some other
studies already tried to characterize these signals by their fractal dimension. This
paper is aimed at studying the correlation between the fractal dimension of surface
EMG signal recorded over Rectus Femoris muscles during a vertical jump and the height
reached in that jump. Healthy subjects performed vertical jumps at different heights.
Surface EMG from Rectus Femoris was recorded and the height of each jump was measured
by an optoelectronic motion capture system. Fractal dimension of sEMG was computed
and the correlation between fractal dimension and eight of the jump was studied. Linear
regression analysis showed a very high correlation coefficient between the fractal
dimension and the height of the jump for all the subjects. The results of this study
show that the fractal dimension is able to characterize the EMG signal and it can
be related to the performance of the jump. Fractal dimension is therefore an useful
tool for EMG interpretation$$$$
Recent developments in the theory of plasma-based collisionally excited x-ray lasers
(XRL) have shown an optimization potential based on the dependence of the absorption
region of the pumping laser on its angle of incidence on the plasma. For the experimental
proof of this idea, a number of diagnostic schemes were developed, tested, qualified
and applied. A high-resolution imaging system, yielding the keV emission profile perpendicular
to the target surface, provided positions of the hottest plasma regions, interesting
for the benchmarking of plasma simulation codes. The implementation of a highly efficient
spectrometer for the plasma emission made it possible to gain information about the
abundance of the ionization states necessary for the laser action in the plasma. The
intensity distribution and deflection angle of the pump laser beam could be imaged
for single XRL shots, giving access to its refraction process within the plasma. During
a European collaboration campaign at the Lund Laser Center, Sweden, the optimization
of the pumping laser incidence angle resulted in a reduction of the required pumping
energy for a Ni-like Mo XRL, which enabled the operation at a repetition rate of 10
Hz. Using the experiences gained there, the XRL performance at the PHELIX facility,
GSI Darmstadt with respect to achievable repetition rate and at wavelengths below
20 nm was significantly improved, and also important information for the development
towards multi-100 eV plasma XRLs was acquired. Due to the setup improvements achieved
during the work for this thesis, the PHELIX XRL system now has reached a degree of
reproducibility and versatility which is sufficient for demanding applications like
the XRL spectroscopy of heavy ions. In addition, a European research campaign, aiming
towards plasma XRLs approaching the water-window (wavelengths below 5 nm) was initiated.
(orig.)$$$$
We present a systematic analysis on the role of the quantum dot (QD) shape in the
influence of the phonon bath on the dynamics of a QD cavity QED system. The spectral
functions of the phonon bath in three representative QD shapes: spherical, ellipsoidal,
and disk, are calculated from the carrier wave functions subjected to the confinement
potential provided by the corresponding shape. The obtained spectral functions are
used to calculate three main effects brought by the phonon bath, i.e., the coupling
renormalization, the off-resonance assisted feeding rate and the pure dephasing rate.
It is found that the spectral function of a disk QD has the widest distribution, hence
the phonon bath in a disk QD can lead to the smallest renormalization factor, the
largest dephasing rate in the short time domains(≤ 2 ps), and the off-resonance
assisted feeding can support the widest detuning. Except for the pure dephasing rate
in the long time domains, all the influences brought by the phonon bath show serious
shape dependence. (electromagnetism, optics, acoustics, heat transfer, classical mechanics,
and fluid dynamics)$$$$
The aim of the presented experiment was to investigate the feasibility of satellite-based
global quantum key distribution. In this context, a free-space quantum key distribution
experiment over a real distance of 144 km was performed. The transmitter and the receiver
were situated in 2500 m altitude on the Canary Islands of La Palma and Tenerife, respectively.
The small and compact transmitter unit generated attenuated laser pulses, that were
sent to the receiver via a 15-cm optical telescope. The receiver unit for polarisation
analysis and detection of the sent pulses was integrated into an existing mirror telescope
designed for classical optical satellite communications. To ensure the required stability
and efficiency of the optical link in the presence of atmospheric turbulence, the
two telescopes were equipped with a bi-directional automatic tracking system. Still,
due to stray light and high optical attenuation, secure key exchange would not be
possible using attenuated pulses in connection with the standard BB84 protocol. The
photon number statistics of attenuated pulses follows a Poissonian distribution. Hence,
by removing a photon from all pulses containing two or more photons, an eavesdropper
could measure its polarisation without disturbing the polarisation state of the remaining
pulse. In this way, he can gain information about the key without introducing detectable
errors. To protect against such attacks, the presented experiment employed the recently
developed method of using additional ''decoy'' states, i.e., the the intensity of
the pulses created by the transmitter were varied in a random manner. By analysing
the detection probabilities of the different pulses individually, a photon-number-splitting
attack can be detected. Thanks to the decoy-state analysis, the secrecy of the resulting
quantum key could be ensured despite the Poissonian nature of the emitted pulses.
For a channel attenuation as high as 35 dB, a secret key rate of up to 250 bit/s was
achieved. Our outdoor experiment was carried out under real atmospheric conditions
and with a channel attenuation comparable to an optical link from ground to a satellite
in low earth orbit. Hence, it definitely shows the feasibility of satellite-based
quantum key distribution using a technologically comparatively simple system. (orig.)$$$$
A remarkable variety of particle acceleration occurs in the solar system, from lightning-related
acceleration of electrons to tens of MeV energy in less than a millisecond in planetary
atmospheres; to acceleration of auroral and radiation belt particles in planetary
magnetospheres; to acceleration at planetary bow shocks, co-rotating interplanetary
region shocks, shocks driven by fast coronal mass ejections, and at the heliospheric
termination shock; to acceleration in magnetic reconnection regions in solar flares
and at planetary magnetopause and magnetotail current sheets. These acceleration processes
often occur in conjunction with transient energy releases, and some are very efficient,
with the accelerated particles containing ∼ 10-50% of the total energy released. Others
are highly selective; for example, the acceleration in ^{3}He-rich solar particle
events enriches ^{3}He by a factor of up to 10,000 or more relative to ^{4}He.
Unlike acceleration processes outside the solar system, the accelerated particles
and the physical conditions in the acceleration region can be studied through direct
in situ measurements, and/or through detailed imaging and spectroscopy. Here I review
recent observations of these acceleration phenomena, our current understanding of
the physics involved, and the applicability to particle acceleration elsewhere in
the universe. (author)$$$$
The equations of fluid mechanics, coupled with those that describe matter transportation
at the molecular level must be handled effectively. Putting the fluid into equations,
we model the Bloch NMR flow equations into the harmonic wave equation for the analysis
of general fluid flow. We derived the solution of the modelled harmonic equation in
non relativistic quantum mechanics and discuss its semi classical application to illustrate
its potential wide-ranging usefulness in the search for the best possible data obtainable
for general fluid flow analysis. Representing the solution of the derived harmonic
wave equation by a normalized state function is quite useful in generating the properly
normalized wave functions and in the efficient evaluation of expectation values of
many operators that can be fundamental to the analysis of fluid flow especially at
the microscopic level. (author)$$$$
Temporally coherent x-ray laser with the high order harmonic light 246 KB - http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/37/005/37005808.pdf - Text Version by Hasegawa, Noboru; Kawachi, Tetsuya; Kishimoto, Maki; Sukegawa, Kouta; Tanaka, Momoko;
Ochi, Yoshihiro; Nishikino, Masaharu; Kawazome, Hayato; Nagashima, Keisuke (Japan
Atomic Energy Research Inst., Kansai Research Establishment, Kizu, Kyoto (Japan)) fromProceedings of the 6th symposium on advanced photon research Read MoreCollapse
[en]
We obtained the neon-like manganese x-ray laser with the injection of the high order
harmonic light as the seed x-ray at the wavelength of 26.9 nm for the purpose of generation
of the temporally coherent x-ray laser. The x-ray amplifier, which has quite narrow
spectral width, selected and amplified the temporally coherent mode of the harmonic
light. The temporal coherence of the mode selected harmonic light was nearly transform
limited pulse, and the obtained x-ray laser with the seed x-ray expected to be nearly
temporally coherent x-ray. (author)$$$$
We investigate a mechanism of nonlinear phenomena in laser-plasma interaction, a laser
wakefield excited by intense laser pulses, and the possibility of generating an intense
bright electron source by an intense laser pulse. We need to understand and further
employ some of these phenomena for our purposes. We measure self-focusing, filamentation,
and the anomalous blueshift of the laser pulse. The ionization of gas with the self-focusing
causes a broad continuous spectrum with blueshift. The normal blueshift depends on
the laser intensity and the plasma density. We, however, have found different phenomenon.
The laser spectrum shifts to fixed wavelength independent of the laser power and gas
pressure above some critical power. We call the phenomenon 'anomalous blueshift'.
The results are explained by the formation of filaments. An intense laser pulse can
excite a laser wakefield in plasma. The coherent wakefield excited by 2 TW, 50 fs
laser pulses in a gas-jet plasma around 10^{18} cm^{-3} is measured
with a time-resolved frequency domain interferometer (FDI). The density distribution
of the helium gas is measured with a time-resolved Mach-Zehnder interferometer to
search for the optimum laser focus position and timing in the gas-jet. The results
show an accelerating wakefield excitation of 20 GeV/m with good coherency, which is
useful for ultrahigh gradient particle acceleration in a compact system. This is the
first time-resolved measurement of laser wakefield excitation in a gas-jet plasma.
The experimental results are compared with a Particle-in-Cell (PIC) simulation. The
pump-probe interferometer system of FDI and the anomalous blueshift will be modified
to the optical injection system as a relativistic electron beam injector. In 1D PIC
simulation we obtain the results of high quality intense electron beam acceleration.
These results illuminate the possibility of a high energy and a high quality electron
beam acceleration. (author)$$$$
Environmental standards which govern outdoor wireless equipment can stipulate stringent
conditions: high solar loads (up to 1 kW/m^{2}), ambient temperatures as high
as 55°C and negligible wind speeds (0 m/s). These challenges result in restrictions
on power dissipation within a given envelope, due to the limited heat transfer rates
achievable with passive cooling. This paper addresses an outdoor wireless device which
features two segregated heat sink structures arranged vertically within a shielded
chimney structure: a primary sink to cool temperature-sensitive components; and a
secondary sink for high power devices. Enhanced convective cooling of the primary
sink is achieved due to the increased mass flow within the chimney generated by the
secondary sink. An unshielded heat sink was examined numerically, theoretically and
experimentally, to verify the applicability of the methods employed. Nusselt numbers
were compared for three cases: an unshielded heat sink; a sink located at the inlet
of a shield; and a primary heat sink in a segregated structure. The heat sink, when
placed at the inlet of a shield three times the length of the sink, augmented the
Nusselt number by an average of 64% compared to the unshielded case. The Nusselt number
of the primary was found to increase proportionally with the temperature of the secondary
sink, and the optimum vertical spacing between the primary and secondary sinks was
found to be close to zero, provided that conductive transfer between the sinks was
suppressed.$$$$