3/2004
Contents:

K.Murawski and A.Zawada, The Influence of Wavenoise on Wave Speeds and Amplitudes of Surfacegravity Waves
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R.Ogrodowczyk and K.Murawski, Parallel Computing in a Network of Workstations
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L.Pasini and S.Feliziani, A Method to Build NetworkofQueuesBased Simulators for Communication Systems
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E.Frulloni and S.Fiori, Quality Enhancement of EddyCurrentBased NonDestructive Evaluation Data through Independent Component Analysis
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M.Kekana and J.Badur, An Analysis of a Piezoelastic Restrictor Using a Capacitive Shunt
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E.A.Anagnostakis, Finite Difference Method Determination of the Nanoheterointerface Wavefunction Engineering of Intersubband LASER Functionality
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G.Bergmanski, M.Bialoskorski, M.RychcikLeyk, A.Witkowska, J.Rybicki, S.Frigio and S.Feliziani, The Structure of Rarefied and Densified PbSiO_{3} Glass: a Molecular Dynamics Study
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M.Brylinski, W.Jurkowski, L.Konieczny and I.Roterman, Limitation of Conformational Space for Proteins  Early Stage Folding Simulation of Human α and β Hemoglobin Chains
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K.Grzeda, A.Nowakowski and P.Czarnul, Analysis of Nonlinear Properties of Cardiomyocyte Cellular Membranes
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B.G.Trzeciak, M.Jaskiewicz and J.Siebert, Using the Internet to Determine Fatal Cardiovascular Risk in the Polish Population
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From the History of Science in Gdansk

A.Januszajtis,
Stroke of Fate
Abstracts:

K.Murawski and A.Zawada, The Influence of Wavenoise on Wave Speeds and Amplitudes of Surfacegravity Waves
We have analytically examined surfacegravity waves which propagate in
space and timedependent random velocity fields. Using a perturbative method,
we have derived a dispersion relation which is solved for the case of wavenoise
whose spectrum E(k,ω) ∼
E(k)δ(ωc_{r}k), where δ is
Dirac's deltafunction and c_{r} is the random phase speed. We have found that
for a dispersionless noise resonance occurs when c_{r} is equal to the
group velocity c_{g} of the surfacegravity wave. In this resonance the real
part of the wave frequency is finite, but its imaginary part exhibits the
characteristic 1/x singularity. The wavenoise interacts with a packet of
the surfacegravity waves in such a way that the waves are attenuated for
c_{r} < c_{g} and are amplified for c_{r} > c_{g}. As the
real part is positive for high values of k, the surfacegravity waves are accelerated by the
wavenoise.

R.Ogrodowczyk and K.Murawski, Parallel Computing in a Network of Workstations
In this paper we describe a few architectures and software for
parallelprocessing computers. We have tested a cluster constructed with
the use of MPI. All tests have been performed for one and twodimensional
magnetohydrodynamic plasma. We have concluded from the results of these tests that
a simple problem should be run in a sequential node, as its execution time does
not essentially decrease with the number of processors used. At the same time,
the execution time of a complex problem decreases significantly with the
number of processors. In the case of twodimensional plasma the acceleration
factor has reached the value of 3.7 with the use of 10 processors.

L.Pasini and S.Feliziani, A Method to Build NetworkofQueuesBased Simulators for Communication Systems
In this study we build a library of new object types whose architecture
is based on models of networksofqueues to simulate communication networks.
We also define a class of procedures to automatically generate a simulator
of a generic communication network described by the library's objects.

E.Frulloni and S.Fiori, Quality Enhancement of EddyCurrentBased NonDestructive Evaluation Data through Independent Component Analysis
The aim of this paper is to examine the performance of an independent
component analysis algorithm based on neural networks applied to the solution
of an electrical engineering problem related to nondestructive evaluation of
conductive objects. The proposed application is assessed through computer
experiments carried out on realworld data, which prove the usefulness of
this nondestructive evaluation technique.

M.Kekana and J.Badur, An Analysis of a Piezoelastic Restrictor Using a Capacitive Shunt
The study investigates the control of structural response using collocated
piezoelectric elements mounted on both sides of beam. A capacitive shunt
is introduced into the circuitry to provide passive control of the beam's
configuration. The energy method is used to develop the structure's governing
equations. In order to select the appropriate electrostatic
relations for the material, i.e. conductor or insulator material, the free
charge rearrangement time is used. The effects of the capacitive shunt are
introduced into the electrostatic relations using additive decomposition
of capacitance. As an application of the model, a piezoelastic beam
restrictor using a capacitive shunt is investigated. Numerical results show
that the capacitive shunt can effect passive control of the configuration of
the beam.

E.A.Anagnostakis, Finite Difference Method Determination of the Nanoheterointerface Wavefunction Engineering of Intersubband LASER Functionality
A novel LASER action nanoheterostructure of the intersubband, midinfrared
functionality type is designed on the basis of optically pumped dual resonant
tunnelling of conductivity electrons within an appropriately energetically
determined scheme of five subbands hosted by two communicating asymmetric,
approximately rectangular quantum wells (QWs).
The upper LASER action level employed is the second excited subband of the
nanostructure's back, wider QW and is provided with electrons via
resonant tunnelling from the first excited subband of the nanostructure's front
QW populated through remotely ignited optical pumping out of the
local fundamental subband.
The first excited back QW subband functions as the lower LASER action level,
directly delivering the received electrons to the
local fundamental subband  via fast vertical longitudinal optical phonon
scattering  wherefrom they are being recycled back to the nanostructure's front
QW fundamental subband by virtue of a secondreverse senseresonant
tunnellingmediated normal charge transport mechanism.
The handling of the de Broglie wavefunction problem evolves into a numerical
calculation of a SturmLiouville eigensystem solved by means of a finite
difference method employing an appropriate tridiagonal coefficient matrix.

G.Bergmanski, M.Bialoskorski, M.RychcikLeyk, A.Witkowska, J.Rybicki, S.Frigio and S.Feliziani, The Structure of Rarefied and Densified PbSiO_{3} Glass: a Molecular Dynamics Study
The paper is a molecular dynamics (MD) study of the structure of rarefied
and densified leadsilicate glass of the PbSiO_{3} composition. Simulations
have been performed in the constant volume regime for systems with densities
of 3000, 4000, 5000, 5970 (normal density), 7000 and 8000kg/m^{3},
using a twobody potential (BornMayer repulsive forces and Coulomb forces due to full
ionic charges). All the systems were initially prepared as well equilibrated
hot melts, and then slowly cooled down to 300K. The information on
shortrange correlations was obtained in a conventional way (from radial and
angular distribution functions), while the middlerange order was studied via
cationanion ring analysis, using our new programme for basal ring
determination. The structure of rarefied and densified glasses is compared
with the structure of the same glasses under normal conditions. Moreover, the
present results on PbSiO_{3} glass are compared with the corresponding data
previously obtained for rarefied and densified PbGeO_{3} glass (Rybicki
et al. 2001 Comput. Met. Sci. Technol. 7 91112).

M.Brylinski, W.Jurkowski, L.Konieczny and I.Roterman, Limitation of Conformational Space for Proteins  Early Stage Folding Simulation of Human α and β Hemoglobin Chains
The starting structure of ab initio protein structure prediction
methods is problematic as the energy minimization procedure stops
searching for an optimal structure of the function's local minimum. The method
presented in the paper helps to find the starting structure. Although it is
based on the known native protein structure, it seems to deliver a key to the
formation of a common universal starting structure. The limited conformational
subspace, defined on the basis of a geometrical model of the polypeptide backbone
with the side chainside chain interaction excluded, seems to deliver the original
structure of the polypeptide, which is modified step by step as the role of
the side chain interactions increases during the energy minimization
procedure. Here, the method is applied to human hemoglobin chains α and
β to test the applicability of the method to proteins with a high content
of helical forms and lacking disulphide bonds.

K.Grzeda, A.Nowakowski and P.Czarnul, Analysis of Nonlinear Properties of Cardiomyocyte Cellular Membranes
Nonlinear properties of cardiomyocyte membranes are poorly understood. We
model a cell membrane using the BeelerReuter model with the DrouhardRoberge
modification (the BRDR model). Simulations are performed using AC voltage
test excitation of 1 or 100kHz frequency and 1 or 10mV RMS. Values of
currents flowing through the cell membrane are considered to be the response. The
BRDR response is presented at the fundamental frequency and at its second
and third harmonics. The response is mainly contributed to by the timeindependent
potassium current (i_{K1}) during resting membrane potential. The level
of currents varies strongly during the period of action potential.
However, the linear response from the membrane capacitance is relatively high.
The second and third harmonics of the 1kHz/10mV probing voltage carry some
information about the action potential. In particular, it may be used to
investigate the process of repolarization and its disorders.

B.G.Trzeciak, M.Jaskiewicz and J.Siebert, Using the Internet to Determine Fatal Cardiovascular Risk in the Polish Population
We present the first program in Poland to determine the cardiovascular
disease (CVD) risk of individuals, called Ryzyko. The program is freely
available at www.ryzyko.amg.gda.pl. Our program, partially based on
the European SCORECARD program, takes into account parameters such as age,
sex, systolic blood pressure, total cholesterol concentration and cigarette
smoking, and enables internet users to observe themselves to determine the
degree of their CVD risk.
