title:
Experimental Investigation of New Method of Energy Generation in Plasma
  Devices caused by Existence of Physical Space Global Anisotropy

abstract:
  An experimental investigation of a new interaction connected with the
existence of the cosmological vectorial potential, has been carried out. On its
basis, a new method of energy generation with the use of a plasma generator,
has been studied. The experimental results and complete analysis of errors in
the experiments are presented.


title:
Optimization of Quantum Monte Carlo Wave Functions Using Analytical
  Energy Derivatives

abstract:
  An algorithm is proposed to optimize quantum Monte Carlo (QMC) wave functions
based on New ton's method and analytical computation of the first and second
derivatives of the variati onal energy. This direct application of the
variational principle yields significantly low er energy than variance
minimization methods when applied to the same trial wave function.
  Quadratic convergence to the local minimum of the variational parameters is
achieved. A g eneral theorem is presented, which substantially simplifies the
analytic expressions of de rivatives in the case of wave function optimization.
To demonstrate the method, the ground state energies of the first-row elements
are calculated.


title: Genetic Algorithms in Time-Dependent Environments

abstract:
  The influence of time-dependent fitnesses on the infinite population dynamics
of simple genetic algorithms (without crossover) is analyzed. Based on general
arguments, a schematic phase diagram is constructed that allows one to
characterize the asymptotic states in dependence on the mutation rate and the
time scale of changes. Furthermore, the notion of regular changes is raised for
which the population can be shown to converge towards a generalized
quasispecies. Based on this, error thresholds and an optimal mutation rate are
approximately calculated for a generational genetic algorithm with a moving
needle-in-the-haystack landscape. The so found phase diagram is fully
consistent with our general considerations.

categories: physics.bio-ph adap-org cs.NE nlin.AO q-bio


title: Do Gravitational Fields Have Mass? Or on the Nature of Dark Matter

abstract:
  As has been shown before (a brief comment will be given in the text),
relativistic mass and relativistic time dilation of moving bodies are
equivalent as well as time and mass in the rest frame. This implies that the
time dilation due to the gravitational field is combined with inertial and
gravitational mass as well and permits the computation of the gravitational
action of the vacuum constituting the gravitational field in any distance from
the source of the field. Theoretical predictions are compared with experimental
results and it is shown that many known astrophysical and gravitational
phenomena, especially the so-called dark or missing matter, owe their existence
to the gravitational effects of the mass of the field-vacuum.


title: Stationary Velocity and Charge Distributions of Grains in Dusty Plasmas

abstract:
  Within the kinetic approach velocity and charge distributions of grains in
stationary dusty plasmas are calculated and the relations between the effective
temperatures of such distributions and plasma parameters are established. It is
found that the effective temperature which determines the velocity grain
distribution could be anomalously large due to the action of accelerating ionic
bombarding force. The possibility to apply the results obtained to the
explanation of the increasing grain temperature in the course of the
Coulomb-crystal melting by reduction of the gas pressure is discussed. This
paper was received by Phys.Rev.Lett. on 11 August 1999. As potential referees
the authors offered to Editor the following persons: V.N.Tsytovich, Russia;
R.Bingham, UK; D.Resendes, Portugal; G.Morfill, P.Shukla, Y.M.Yu., Germany.


title:
Expression of Interest in R&D towards a Neutrino Factory Based on a
  Storage Ring and a Muon Collider

abstract:
  We are exploring the feasibility of a neutrino factory based on a muon
storage ring. In this, beams of nu_mu and nubar_e arise from the decay of mu-
particles (or alternatively, nubar_mu and nu_e from mu+). The muons come from
the decay of low-energy pions produced by a megawatt proton beam incident on a
nuclear target. The muons are captured into a magnetic channel, "cooled" by
ionization in liquid hydrogen, accelerated to energy of order 50 GeV, and
injected into a storage ring. A nonhorizontal ring can deliver neutrino beams
to an on-site detector, as well as to two off-site detectors separated by
global distances. Such a neutrino factory is a challenging extension of present
accelerator technology. It is also a natural path to a muon collider, in that
both facilities share many common elements upstream of their storage rings.
Prior to a formal design study, R&D must be performed in several keys areas,
such detailed simulations and actual targetry and cooling experiments. This in
an excellent opportunity to advance the field of accelerator physics both at
national laboratories and at universities.


title: Coherent Backscattering of Light by Cold Atoms

abstract:
  Light propagating in an optically thick sample experiences multiple
scattering. It is now known that interferences alter this propagation, leading
to an enhanced backscattering, a manifestation of weak localization of light in
such diffuse samples. This phenomenon has been extensively studied with
classical scatterers. In this letter we report the first experimental evidence
for coherent backscattering of light in a laser-cooled gas of Rubidium atoms.


title: On Gravitational Shielding in Electromagnetic Fields

abstract:
  We show the presence of an electromagnetic field can cause a gravitational
Meissner effect and, as a result, a gravitational shielding. With this aim in
view we must first unveil the following problems : generalized Maxwell
equations, generalized London equations, generalized Meissner effect,
generalized shielding, etc.


title:
Calculation of the free-free transitions in the electron-hydrogen
  scattering S-wave model

abstract:
  The S-wave model of electron-hydrogen scattering is evaluated using the
convergent close-coupling method with an emphasis on scattering from excited
states including an initial state from the target continuum. Convergence is
found for discrete excitations and the elastic free-free transition. The latter
is particularly interesting given the corresponding potential matrix elements
are divergent.


title: On the Conservation of Physical Quantities

abstract:
  Certain transformations of isolated physical systems underlying various
conservation laws in physics are noted. As regards each of these
transformations, there is a theoretical action that is equivalent to a matched
physical action on the system. Evidence supporting this thesis is found in
experimental psychological research where results of various experiments allow
that the imagined rotation of an object is analogous to a physical rotation.
The conservation laws based on the transformations noted are theoretical or
mental in nature to the same extent that they are physical. When one of the
conservation principles noted is tested by carrying out the relevant
transformation on the system, this test is essentially one of the influence of
mental activity on physical reality.


title:
Second virial coefficient for the Landau diamagnetism of a two component
  plasma

abstract:
  This paper investigates the density expansion of the thermodynamic properties
of a two component plasma under the influence of a weak constant uniform
magnetic field. We start with the fugacity expansion for the Helmholtz free
energy. The leading terms with respect to the density are calculated by a
perturbation expansion with respect to the magnetic field. We find a new
magnetic virial function for a low density plasma which is exact in quadratic
order with respect to the magnetic field. Using these results we compute the
magnetization and the magnetic susceptibility.


title: Is the best estimate of power equal to the power of the best estimate?

abstract:
  In an inverse problem, such as the determination of brain activity given
magnetic field measurements outside the head, the main quantity of interest is
often the power associated with a source. The `standard' way to determine this
has been to find the best linear estimate of the source and calculate the power
associated with this. This paper proposes an alternative method and then
relationship to this previous method of estimation is explored both
algebraically and by numerical simulation.
  In abstract terms the problem can be stated as follows. Let H be a Hilbert
space with inner product <, >. Let L be a linear map: H->R^n. Suppose that we
are a given data vector b in R^n such that b=Lx+e where e is a vector of random
variables with zero mean and given covariance matrix that represents
measurement errors. The problem that is addressed in this paper is to estimate
<x,Xx> where X is an operator on H (e.g. the characteristic function of a
region of interest).
  Keywords: Linear inverse problem, biomagnetic inverse problem,
magnetoencephalography (MEG).


title: Seismic Wave Recording by 2S-Seismographs

abstract:
  Researchers of seismic waves may construct a new seismographic recording
adding one seismometer to each component of a conventional seismic station. The
two identical conventional seismometers are set up in position of perpendicular
and are connected in parallel feeding one recording device (digital or analog).
This use of the seismometers (which they may be both horizontal or, one is
vertical) is called "two seismometers seismograph" or simply "2S-S".
  2S-seismograph performs new capabilities: 1.-it cause to a higher gain which
is based on directly ground motion energy from the two orthogonal components of
signals, 2.-it has a much smoother response curve than that of the single use
of seismometer,3.-because of this smoothing, we are able to apply a higher
level of static magnification which cause to widening the response at its both
ends, therefore, 2S-System enable to work with a larger dynamic range
frequency, 4.- it has a directional and motional filtering property which may
be used in some cases advantageously, The contribution of "1", "2", "3" and "4"
correspond to unique instrumental improvements for which seismography are ever
needed.
  Data which are obtained from the 2S-Ss have also more advantageous properties
comparing with even that of ARRAY's: 5.-it is possible to record signals with
their larger plane components all the time by a second 2S-S connected with the
opposite ends, 6.-seismic wave types (P,S,R,L) can often be recorded separately
on a separated 2S-seismogram since researchers usually deal with a known area
of research, 7.-some implicit weak signals, which can not be readable as a
phase on the conventional seismograms, become recorded newly and readably by
the 2S-Ss


title: The RR interval spectrum, the ECG signal and aliasing

abstract:
  A reliable spectral analysis requires sampling rate at least twice as large
as the frequency bound, otherwise the analysis will be unreliable and plagued
with aliasing distortions. The RR samplings do not satisfy the above
requirements and therefore their spectral analysis might be unreliable.
  In order to demonstrate the feasibility of aliasing in RR spectral analysis,
we have done an experiment which have shown clearly how the aliasing was
developed. In the experiments, one of us (A.G) had kept his high breathing rate
constant with the aid of metronome for more than 5 minutes. The breathing rate
was larger than one-half the heart rate. Very accurate results were obtained
and the resulting aliasing well understood. To our best knowledge this is the
first controlled experiment of this kind coducted on humans.
  We compared the RR spectral analysis with the spectrum of the ECG signals
from which the RR intervals were extracted. In the significant for RR analysis
frequencies (below one-half Hertz) significant differences were observed.
  In conclusion we recommend to study the spectral analysis of the ECG signal
in the free of aliasing frequency range.


title:
Dirac's Representation Theory as a Framework for Signal Theory. I.
  Discrete Finite Signals

abstract:
  We demonstrate that the Dirac representation theory can be effectively
adjusted and applied to signal theory. The main emphasis is on orthogonality as
the principal physical requirement. The particular role of the identity and
projection operators is stressed. A Dirac space is defined, which is spanned by
an orthonormal basis labeled with the time points. An infinite number of
orthonormal bases is found which are labeled with frequencies, they are
distinguished by the continuous parameter a. In a way, similar to one used in
quantum mechanics, self-adjoint operators (observables) and averages
(expectation values) are defined. Non orthonormal bases are discussed and it is
shown, in an example, that they are less stable compared to the orthonormal
ones. A variant of the sampling theorem for finite signals is derived. The
aliasing phenomenon is described in the paper in terms of aliasing symmetry.
Relations between different bases are derived. The uncertainty principle for
finite signals is discussed.


title:
Dirac's Representation Theory as a Framework for Signal Theory. II.
  Infinite Duration and Continuous Signals

abstract:
  We generalize previous results and demonstrate that the Dirac representation
theory can be effectively adjusted and applied to continuous or discrete
signals of infinite time duration. The role of the identity and projection
operators is emphasized. The sampling theorem is viewed from the point of view
of orthogonal physical states. An orthogonal basis which spanned the time
space, ceases to be orthogonal and becomes overcomplete if the domain of
frequencies is restricted in a bandwidth. In this case there exists an infinite
number of sub-bases of discrete times which are orthogonal and complete. The
relation between the overcomplete bases and a complete one is the essence of
the sampling theorem. The signal theory is reformulated in the framework of the
Dirac bra-kets. The case of signals existing for positive time is treated in
detail.


title: Cold Collision Frequency Shift of an Optical Spectrum of a Trapped Gas

abstract:
  We develop an exact sum rule that relates the spectral shift of a trapped gas
undergoing cold collisions to measurable quantities of the system. The method
demonstrates the dependence of the cold collision frequency shift on the
quantum degeneracy of the gas and facilitates extracting scattering lengths
from the data. We apply the method to analyzing spectral data for magnetically
trapped hydrogen atoms and determine the value of the $1S-2S$ scattering
length.


title: Numerical Simulation Of Warm Rain Process

abstract:
  Extensive aircraft cloud physical observations made in more than 2000
tropical cumulus clouds indicated new observational evidence viz., (1)
horizontal structure of the air flow inside the cloud has consistent variations
with successive positive and negative values of vertical velocity
representative of ascending and descending currents, (2) regions of ascending
currents are associated with higher liquid water content (LWC) and negative
cloud drop charges and the descending currents are associated with lower LWC
and positive cloud drop charge, (3) width of the ascending and descending
currents is about 100 m, (4) ratio of the measured LWC (q) to that of the
adiabatic value (qa) = 0.60 at cloud-base levels, (5) increase in the cloud
electrical activity with LWC, (6) cloud drop size spectra is unimodal near the
cloud-base and multimodal at higher levels, (7) in-cloud temperatures are
colder than the environment, (8) environmental lapse rates are equal to the
saturated adiabatic value while inside the cloud they are lower, (9) positive
increments in the LWC are associated with the increments in temperature inside
the cloud and the immediate environment and (10) variances of in-cloud
temperature and humidity are larger in the regions where the values of the LWC
are higher. The observed dynamical and physical characteristics of clouds
cannot be explained by the presently available cloud models. An alternative
cell dynamical system cloud model which predicts the observed cloud
characteristics is discussed in this paper.


title: Is the Lorentz Transformation Distance-Dependent?

abstract:
  An analysis of the Lorentz transformation shows that the unchangeability of
the space-time coordinates of the inertial systems under consideration and the
possibility of a direct projection of those coordinates onto another are the
underlying assumptions as to its unlimited validity. It is demonstrated that
from a empiric-physical point of view these assumptions are not given in the
case of inertial systems separated by very large distances. Analogous to the
impossibility to measure motion relative to absolute space, it turns out to be
physically non feasible to extend the coordinate system of any reference frame
considered at rest relative to a distantly moving system for a direct
comparision of the coordinates, and vice versa. The extended Lorentz
transformation strictly based on first physical principles predicts the
possibility of superluminal propagation of very distant material bodies and, in
this case, the generation of Cerenkov radiation out of the quantum vacuum. For
many astrophysical phenomena and their experimentally verified properties this
yields a novel view.


title:
An improved Rosenbluth Monte Carlo scheme for cluster counting and
  lattice animal enumeration

abstract:
  We describe an algorithm for the Rosenbluth Monte Carlo enumeration of
clusters and lattice animals. The method may also be used to calculate
associated properties such as moments or perimeter multiplicities of the
clusters. The new scheme is an extension of the Rosenbluth method for growing
polymer chains and is a simplification of a scheme reported earlier by one of
the authors. The algorithm may be used to estimate the number of distinct
lattice animals on any lattice topology. The method is validated against exact
and Monte Carlo enumerations for clusters up to size 50, on a two dimensional
square lattice and three dimensional simple cubic lattice. The method may be
readily adapted to yield Boltzmann weighted averages over clusters.


title: Quasilinear theory of the 2D Euler equation

abstract:
  We develop a quasilinear theory of the 2D Euler equation and derive an
integro-differential equation for the evolution of the coarse-grained
vorticity. This equation respects all the invariance properties of the Euler
equation and conserves angular momentum in a circular domain and linear impulse
in a channel. We show under which hypothesis we can derive a H-theorem for the
Fermi-Dirac entropy and make the connection with statistical theories of 2D
turbulence.


title:
Matter Creation or Destruction in a Variable Gravitational Field as
  Predicted by a Scalar Theory of Gravitation

abstract:
  Newton's second law: "force = time-derivative of momentum", may also be
defined for theories of gravitation endowing space-time with a curved metric.
Thus, Einstein's assumption of a geodesic motion may be rewritten in that form,
and it corresponds to a velocity-dependent gravity acceleration vector g. In
contrast, the investigated theory states that, in the preferred reference frame
assumed by the theory, vector g does not depend on the velocity. It recovers
geodesic motion only for a constant gravitational field. This leads to a
different equation for continuum dynamics, as compared with general relativity.
For a perfect fluid, this alternative dynamics predicts tenuous amounts of
matter production or destruction, by a reversible exchange with the
gravitational field. This exchange is completely determined by the dynamical
equation and the scalar equation of the gravitational field. In contrast, the
usual equation for relativistic continuum dynamics allows matter production
only if some additional field is assumed, and the production rate must be
phenomenologically postulated. With the alternative equation, the mass
conservation is very nearly recovered for a weak field. The explosion
(implosion) of a spherical compact body implies some matter production
(destruction).


title: Multipositronic systems

abstract:
  The stability of Coulombic systems containing positrons are investigated by
the stochastic variational method. The existence of several new exotic atoms
are predicted, including HPse+, LiPs2e+, or (H-,Ps2). Similar systems
(replacing the positrons by holes) might be observed in semiconductors.

categories: physics.atom-ph astro-ph cond-mat physics.chem-ph


title: The critical manifold of the Lorentz-Dirac equation

abstract:
  We investigate the solutions to the Lorentz-Dirac equation and show that its
solution flow has a structure identical to the one of renormalization group
flows in critical phenomena. The physical solutions of the Lorentz-Dirac
equation lie on the critical surface. The critical surface is repelling, i.e.
any slight deviation from it is amplified and as a result the solution runs
away to infinity. On the other hand, Dirac's asymptotic condition (acceleration
vanishes for long times) forces the solution to be on the critical manifold.
The critical surface can be determined perturbatively. Thereby one obtains an
effective second order equation, which we apply to various cases, in particular
to the motion of an electron in a Penning trap.


title:
Conserved Currents of the Maxwell Equations with Electric and Magnetic
  Sources

abstract:
  New Lagrangians, depending on the field strengths and the electric and
magnetic sources are found, which lead to the Maxwell equations. One new
feature is that the equations of motion are obtained by varying the Lagrangian
with respect to both the field strengths and the sources. In this way,
conserved currents can be found for the field strengths and the electric or
magnetic sources. Furthermore, using the equations of motion, the electric or
magnetic sources can be eliminated, leading to conserved currents for the field
strengths only (in the presence of electric and magnetic sources). Another new
feature is the construction of a Lagrangian invariant under the duality
transformation for both field strengths and electric and magnetic sources. The
conserved current, after the elimination of electric and magnetic sources,
depends on the field strengths only. The conserved quantity is related to the
total helicity of the electromagnetic field.


title:
Evaluation of the Extension of the Cerebral Blood Flow and its Main
  Parameters

abstract:
  Among the major factors controlling the cerebral blood flow (CBF) - cerebral
perfusion pressure, arterial partial pressure of oxygen (PaO2), cerebral
metabolism, arterial partial pressure of carbon dioxide (PaCO2), and cardiac
output, the effect of PaCO2 is peculiar in being independent of autoregulatory
CBF mechanisms and it allows to explore the full range of the CBF. We have
developed a simple physical model, and have derived a simple four parameter
formula, relating the CBF to PaCO2. The parameters can be extracted in an easy
way, directly from the experimental data. With this model five experimental
data sets of human, rats, baboons and dogs were well fitted. The same type of
parametrization was also used successfully for fitting experimental data of
PaO2 of dogs. We have also looked on the dependence of the parameters on other
factors and were able to evaluate their dependence on the mean arterial blood
pressure.


title: One-way multigrid method in electronic structure calculations

abstract:
  We propose a simple and efficient one-way multigrid method for
self-consistent electronic structure calculations based on iterative
diagonalization. Total energy calculations are performed on several different
levels of grids starting from the coarsest grid, with wave functions
transferred to each finer level. The only changes compared to a single grid
calculation are interpolation and orthonormalization steps outside the original
total energy calculation and required only for transferring between grids. This
feature results in a minimal amount of code change, and enables us to employ a
sophisticated interpolation method and noninteger ratio of grid spacings.
Calculations employing a preconditioned conjugate gradient method are presented
for two examples, a quantum dot and a charged molecular system. Use of three
grid levels with grid spacings 2h, 1.5h, and h decreases the computer time by
about a factor of 5 compared to single level calculations.


title:
Object-oriented construction of a multigrid electronic-structure code
  with Fortran 90

abstract:
  We describe the object-oriented implementation of a higher-order
finite-difference density-functional code in Fortran 90. Object-oriented models
of grid and related objects are constructed and employed for the implementation
of an efficient one-way multigrid method we have recently proposed for the
density-functional electronic-structure calculations. Detailed analysis of
performance and strategy of the one-way multigrid scheme will be presented.


title:
Modeling of Liquid Water on CM Meteorite Parent Bodies and Implications
  for Amino Acid Racemization

abstract:
  We have constructed an asteroid model with the intent of tracking the radial
and temporal dependence of temperature and composition throughout a 100-km
diameter CM-type parent body, with emphasis on constraining the temperature and
duration of a liquid water phase. We produce a non-uniform distribution where
liquid water persists longest and is hottest in the deepest zones and the
regolith never sees conditions appropriate to aqueous alteration. We apply the
model predictions of the liquid water characteristics to the evolution of amino
acids. IN some regions of the parent body, very little change occurs in the
amino acids, but for the majority of the asteroid, complete racemization or
even destruction occurs. We attempt to match our thermal model results with CM
meteorite observations, but thus far, our model does not produce scenarios that
are fully consistent with these observations.


title:
Effect of laser polarization in laser-assisted electron-helium inelastic
  collisions:a sturmian approach

abstract:
  The influence of linearly and circularly polarized laser fields on the
dynamics of fast electron-impact excitation in atomic helium is discussed. A
detailed analysis is made in the excitation of 2^1S, 3^1S and 3^1D dressed
states of helium target.


title:
Theoretical Study of Quantum Dissipation and Laser Noise Effects on the
  Atomic Response

abstract:
  The nonlinear dynamics of dissipative quantum systems in incoherent laser
fields is studied in the framework of master equation with random model
describing the laser noise and Markovian approximation for dealing with the
system-bath couplings.


title: The Kinetic of the Atomic Relaxation Induced by Laser Noise

abstract:
  We present a theoretical study of strong laser-atom interactions, when the
laser field parameters are subjected to random processes. The atom is modelled
by a two-level and three-level systems, while the statistical fluctuations of
the laser field are described by a pre-Gaussian model.


title: 9.84 vs. 9.84: The Battle of Bruny and Bailey

abstract:
  At the recent 1999 World Athletics Championships in Sevilla, Spain, Canada's
Bruny Surin matched Donovan Bailey's National and former World Record 100 m
mark of 9.84 s. The unofficial times for each, as read from the photo-finish,
were 9.833 s and 9.835 s respectively. Who, then, is the fastest Canadian of
all time? A possible solution is offered, accounting for drag effects resulting
from ambient tail-winds and altitude.


title:
Residue profile in predivergence sequences as a guide to the origin of
  DNA replication

abstract:
  DNA dependent RNA polymerase core subunits abb' conserved residues at
frequencies most closely matched with codons at stage 10.4-11.1 in code
evolution. An excess of acidic residues (stage 2 additions) lowered this
estimate, but not by more than 2.3 stages. With 1 tryptophan (stage 14
addition) in 529 conserved residues, abb' significantly under-represented this
amino acid, consistent with a cut-off in its residue profile before completion
of the genetic code. Residue profiles in FEN-1 homologs and DNA topoisomerase
I-5' placed their origin at stage 11-13. Prokaryote septation protein, FtsZ,
arose earlier, between stage 8-11. Proteolipid in an ATP-driven proton pump
served as a marker for cell membrane formation. It indicated this event took
place near stage 7. Cell division, DNA replication and transcription were
inferred to have originated in a protocell antecedent of the last common
ancestor. Late-forming residue profiles characterized RNA dependent RNA
replicase, DNA polymerase, reverse transcriptase and ribonucleotide reductase.
This suggests some early processes, including RNA replication and
deoxynucleotide synthesis, once depended on catalysts not found in extant
residue sequences. Early formation of topoisomerase I, and enzymes that
synthesize and trim RNA-DNA hybrids was viewed as evidence for a mixed duplex,
with linear RNA and DNA strands, in the transition from an RNA to DNA genome.


title: Super-paramagnetic clustering of yeast gene expression profiles

abstract:
  High-density DNA arrays, used to monitor gene expression at a genomic scale,
have produced vast amounts of information which require the development of
efficient computational methods to analyze them. The important first step is to
extract the fundamental patterns of gene expression inherent in the data. This
paper describes the application of a novel clustering algorithm,
Super-Paramagnetic Clustering (SPC) to analysis of gene expression profiles
that were generated recently during a study of the yeast cell cycle. SPC was
used to organize genes into biologically relevant clusters that are suggestive
for their co-regulation. Some of the advantages of SPC are its robustness
against noise and initialization, a clear signature of cluster formation and
splitting, and an unsupervised self-organized determination of the number of
clusters at each resolution. Our analysis revealed interesting correlated
behavior of several groups of genes which has not been previously identified.


title: Correlation Dimension Maps of EEG from Epileptic Absences

abstract:
  Purpose: The understanding of brain activity, and in particular events such
as epileptic seizures, lies on the characterisation of the dynamics of the
neural networks. The theory of non-linear dynamics provides signal analysis
techniques which may give new information on the behaviour of such networks.
Methods: We calculated correlation dimension maps for 19-channel EEG data from
3 patients with a total of 7 absence seizures. The signals were analysed
before, during and after the seizures. Phase randomised surrogate data was used
to test chaos. Results: In the seizures of two patients we could distinguish
two dynamical regions on the cerebral cortex, one that seemed to exhibit chaos
whereas the other seemed to exhibit noise. The pattern shown is essentially the
same for seizures triggered by hyperventilation, but differ for seizures
triggered by light flashes. The chaotic dynamics that one seems to observe is
determined by a small number of variables and has low complexity. On the other
hand, in the seizures of another patient no chaotic region was found. Before
and during the seizures no chaos was found either, in all cases. Conclusions:
The application of non-linear signal analysis revealed the existence of
differences in the spatial dynamics associated to absence seizures. This may
contribute to the understanding of those seizures and be of assistance in
clinical diagnosis.


title:
Effect of Optical Coating and Surface Treatments on Mechanical Loss in
  Fused Silica

abstract:
  We report on the mechanical loss in fused silica samples with various surface
treatments and compare them with samples having an optical coating. Mild
surface treatments such as washing in detergent or acetone were not found to
affect the mechanical loss of flame-drawn fused silica fibers stored in air.
However, mechanical contact (with steel calipers) significantly increased the
loss. The application of a high-reflective optical coating of the type used for
the LIGO test masses was found to greatly increase the mechanical loss of
commercially polished fused silica microscope slides. We discuss the
implications for the noise budget of interferometers.


title: On the Biological Advantage of Chirality

abstract:
  The presence of chirality in the main molecules of life may well be not just
a structural artifact, but of pure biological advantage. The possibility of the
existence of a phenomenon of a special mode of interaction, labeled as "chiral
interaction" (CI), for which structural chirality is a necessary condition, is
the main reason for such an advantage. In order to demonstrate such a
possibility, macroscopic chiral devices are introduced and presented as
analogies for such an interaction. For this purpose it is important to make a
clear distinction between geometric and physical chiralities, where the latter
are capable to perform chiral interactions with various media. Apart from
chirality, a few other structural elements are required. In particular, the
presence of an interface that separates between the chiral device and the
medium with which it is interacting. The physical chirality is build into this
very interface where chiral interaction is taking place. On a molecular level,
soluble proteins in particular, the active medium is the presence of random
ionic motion in the aqueous solvent. As a result of chiral interaction a
certain perturbation, or current, is generated and flowing along the coils of $
\alpha$-helix structure in one preferred direction out of two possible ones. A
model for such a chiral interaction is presented and a few significant
consequences are pointed out. In particular, it is important to emphasize the
time-irreversible feature of chiral interaction, which leads to its non-ergodic
nature that is to be considered a necessary condition for evolutionary
processes in biomolecules. There exists an experimental result by Careri et al.
who found a clear linkage between the free protonic motion in the hydration
layer of protein s and their enzymatic activity.


title:
Melting in large sodium clusters: An orbital-free molecular dynamics
  study

abstract:
  The melting-like transition in sodium clusters Na_N, with N=55, 92, and 142
is studied by using constant-energy molecular dynamics simulations. An
orbital-free version of the Car-Parrinello technique is used which scales
linearly with system size allowing investigation of the thermal behaviour of
large clusters. The ground state isomer of Na_142 (an uncomplete three-shell
icosahedron) melts in two steps: the first one (at approx. 240 K) is
characterized by the high mobility of the atoms located on the cluster surface;
the second, homogeneous melting (at approx. 270 K), involves diffusive motion
of all the atoms across the cluster. For the case of Na_92, the icosahedral
structure has a larger number of surface vacancies, and melts in two well
separated steps, surface melting at approx. 130 K and homogeneous melting at
approx. 240 K. Na_55, a complete two-shell icosahedron, melts in a single stage
at approx. 190 K. Our results on homogeneous melting for Na_142 and Na_92 are
in excellent agreement with recent experimental determinations of melting
temperatures and latent heats. However, the experimentally observed enhancement
of the melting temperature around N=55 is not reproduced by the calculations.


title: Moving Embedded Solitons

abstract:
  The first theoretical results are reported predicting {\em moving} solitons
residing inside ({\it embedded} into) the continuous spectrum of radiation
modes. The model taken is a Bragg-grating medium with Kerr nonlinearity and
additional second-derivative (wave) terms. The moving embedded solitons (ESs)
are doubly isolated (of codimension 2), but, nevertheless, structurally stable.
Like quiescent ESs, moving ESs are argued to be stable to linear approximation,
and {\it semi}-stable nonlinearly. Estimates show that moving ESs may be
experimentally observed as $\sim$10 fs pulses with velocity $\leq 1/10$th that
of light.


title:
Frequency selection by soliton excitation in nondegenerate intracavity
  downconversion

abstract:
  We show that soliton excitation in intracavity downconversion naturally
selects a strictly defined frequency difference between the signal and idler
fields. In particular, this phenomenon implies that if the signal has smaller
losses than the idler then its frequency is pulled away from the cavity
resonance and the idler frequency is pulled towards the resonance and {\em vice
versa}. The frequency selection is shown to be closely linked with the relative
energy balance between the idler and signal fields.


title: Embedded Solitons in a Three-Wave System

abstract:
  We report a rich spectrum of isolated solitons residing inside ({\it embedded
} into) the continuous radiation spectrum in a simple model of three-wave
spatial interaction in a second-harmonic-generating planar optical waveguide
equipped with a quasi-one-dimensional Bragg grating. An infinite sequence of
fundamental embedded solitons are found, which differ by the number of internal
oscillations. Branches of these zero-walkoff spatial solitons give rise,
through bifurcations, to several secondary branches of walking solitons. The
structure of the bifurcating branches suggests a multistable configuration of
spatial optical solitons, which may find straightforward applications for
all-optical switching.


title:
Existence criteria for stabilization from the scaling behaviour of
  ionization probabilities

abstract:
  We provide a systematic derivation of the scaling behaviour of various
quantities and establish in particular the scale invariance of the ionization
probability. We discuss the gauge invariance of the scaling properties and the
manner in which they can be exploited as consistency check in explicit
analytical expressions, in perturbation theory, in the Kramers-Henneberger and
Floquet approximation, in upper and lower bound estimates and fully numerical
solutions of the time dependent Schroedinger equation. The scaling invariance
leads to a differential equation which has to be satisfied by the ionization
probability and which yields an alternative criterium for the existence of
atomic bound state stabilization.


title: On Quantum Groups and Their Potential Use in Mathematical Chemistry

abstract:
  The quantum algebra suq(2) is introduced as a deformation of the ordinary Lie
algebra su(2). This is achieved in a simple way by making use of $q$-bosons. In
connection with the quantum algebra suq(2), we discuss the q-analogues of the
harmonic oscillator and the angular momentum. We also introduce q-analogues of
the hydrogen atom by means of a q-deformation of the Pauli equations and of the
so-called Kustaanheimo-Stiefel transformation.

categories: physics.chem-ph math-ph math.MP quant-ph


title:
Coherence Resonance and Noise-Induced Synchronization in Globally
  Coupled Hodgkin-Huxley Neurons

abstract:
  The coherence resonance (CR) of globally coupled Hodgkin-Huxley neurons is
studied. When the neurons are set in the subthreshold regime near the firing
threshold, the additive noise induces limit cycles. The coherence of the system
is optimized by the noise. A bell-shaped curve is found for the peak height of
power spectra of the spike train, being significantly different from a
monotonic behavior for the single neuron. The coupling of the network can
enhance CR in two different ways. In particular, when the coupling is strong
enough, the synchronization of the system is induced and optimized by the
noise. This synchronization leads to a high and wide plateau in the local
measure of coherence curve. The local-noise-induced limit cycle can evolve to a
refined spatiotemporal order through the dynamical optimization among the
autonomous oscillation of an individual neuron, the coupling of the network,
and the local noise.


title: Symmetry in Order-Disorder Changes of Molecular Clusters

abstract:
  The dynamic orientational order-disorder transition of clusters consisting of
octahedral molecules is formulated in terms of symmetry-adapted rotator
functions.
  The transition from a higher-temperature body-centered-cubic, orientationally
disordered phase to a lower-temperature, monoclinic, orientationally-ordered
phase is a two-step process. The higher-temperature transition has two local
minima in the free energy, like a finite-system counterpart of a first-order
transition. Simulations show the lower-temperature transition is continuous.
The analytic theory predicts a temperature of 27K for this transition, for a
59-molecule cluster of tellurium hexafluoride in a good agreement with the ~30K
result of canonical Monte Carlo calculations.


title:
A fast programmable trigger for isolated cluster counting in the BELLE
  experiment

abstract:
  We have developed a fast programmable trigger processor board based on a
field programmable gate array and a complex programmable logic device for use
in the BELLE experiment. The trigger board accommodates 144 ECL input signals,
2 NIM input signals, 24 ECL output signals, and the VME bus specification. An
asynchronous trigger logic for counting isolated clusters is used. We have
obtained trigger latency of 50 ns with a full access to input and output
signals via a VME interface. The trigger logic can be modified at any time
depending on the experimental conditions.


title:
Spin-Lattice Relaxation in Zero-Magnetic Field Indused by Molecular
  Reorientations

abstract:
  The stochastic Liouville method is used to analyze the general problem of
spin-lattice relaxation in zero-field for molecules undergoing Markovian
reorientations.


title:
Electron exchange model potential: Application to positronium-helium
  scattering

abstract:
  The formulation of a suitable nonlocal model potential for electron exchange
is presented, checked with electron-hydrogen and electron-helium scattering,
and applied to the study of elastic and inelastic scattering and ionization of
ortho positronium (Ps) by helium. The elastic scattering and the $n = 2$
excitations of Ps are investigated using a three-Ps-state close-coupling
approximation. The higher ($n\ge 3$) excitations and ionization of Ps atom are
treated in the framework of Born approximation with present exchange.
Calculations are reported of phase shifts, and elastic, Ps-excitation, and
total cross sections. The present target elastic total cross section agrees
well with experimental results at thermal to medium energies.

categories: physics.atm-clus cond-mat nucl-th physics.atom-ph physics.chem-ph quant-ph


title: Low-energy quenching of positronium by helium

abstract:
  Very low-energy scattering of orthopositronium by helium has been
investigated for simultaneous study of elastic cross section and pick-off
quenching rate using a model exchange potential. The present calculational
scheme, while agrees with the measured cross section of Skalsey et al,
reproduces successfully the parameter $^ 1Z_{\makebox{eff}}$, the effective
number of electrons per atom in a singlet state relative to the positron.
Together with the fact that this model potential also leads to an agreement
with measured medium energy cross sections of this system, this study seems to
resolve the long-standing discrepancy at low energies among different
theoretical calculations and experimental measurements.

categories: physics.atm-clus cond-mat nucl-th physics.atom-ph physics.chem-ph


title: Positronium-hydrogen-atom scattering in a five-state model

abstract:
  The scattering of ortho-positronium (Ps) by hydrogen atoms has been
investigated in a five-state coupled-channel model allowing for Ps(1s)H(2s,2p)
and Ps(2s,2p)H(1s) excitations using a recently proposed electron-exchange
model potential. The higher ($n\ge 3$) excitations and ionization of the Ps
atom are calculated using the first Born approximation. Calculations are
reported of scattering lengths, phase shifts, elastic, Ps- and H-excitation,
and total cross sections. Remarkable correlations are observed between the
S-wave Ps-H binding energy and the singlet scattering length, effective range,
and resonance energy obtained in various model calculations. These correlations
suggest that if a Ps-H dynamical model yields the correct result for one of
these four observables, it is expected to lead to the correct result for the
other three. The present model, which is constructed so as to reproduce the
Ps-H resonance at 4.01 eV, automatically yields a Ps-H bound state at -1.05 eV
which compares well with the accurate value of -1.067 eV. The model leads to a
singlet scattering length of 3.72$a_0$ and effective range of 1.67$a_0$,
whereas the correlations suggest the precise values of $3.50a_0$ and 1.65$a_0$
for these observables, respectively.


title: Effective Field Theory for Highly Ionized Plasmas

abstract:
  We examine the equilibrium properties of hot, dilute, non-relativistic
plasmas. The partition function and density correlation functions of a
classical plasma with several species are expressed in terms of a functional
integral over electrostatic potential distributions. The leading order,
field-theoretic tree approximation automatically includes the effects of Debye
screening. Subleading, one-loop corrections are easily evaluated. The two-loop
corrections, however, have ultraviolet divergences. These correspond to the
short-distance, logarithmic divergence which is encountered in the spatial
integral of the Boltzmann exponential when it is expanded to third order in the
Coulomb potential. Such divergences do not appear in the underlying quantum
theory --- they are rendered finite by quantum fluctuations. We show how such
divergences may be removed and the correct finite theory obtained by
introducing additional local interactions in the manner of modern effective
quantum field theories. We obtain explicit results for density-density
correlation functions through two-loop order and thermodynamic quantities
through three-loop order. The induced couplings are shown to obey
renormalization group equations, and these equations are used to characterize
all leading logarithmic contributions in the theory. A linear combination of
pressure and energy and number densities is shown to be described by a
field-theoretic anomaly. The effective theory allows us to evaluate very easily
the algebraic long-distance decay of density correlation functions.

categories: physics.plasm-ph astro-ph cond-mat.stat-mech hep-ph


title:
New Use of Dimensional Continuation Illustrated by dE/dx in a Plasma and
  the Lamb Shift

abstract:
  Physical processes ranging from the Lamb shift to the energy loss dE/dx of a
charged particle traversing a plasma entail processes that occur over a wide
range of energy or length scales. Different physical mechanisms dominate at one
or the other end of this range. For example, in the energy loss problem, soft
collisions that are screened by collective effects are important at large
distances, while at short distances hard collisions are important where the
exact details of the single-particle interactions must be taken into account.
We introduce a novel application of dimensional continuation. The soft
processes dominate at all scales when the spatial dimension \nu is less than 3,
and we use them to compute the result to leading order for \nu < 3. On the
other hand, the hard processes dominate at all scales for \nu > 3, and we use
them to compute the result to leading order for these spatial dimensions. We
then explain why the sum of the analytic continuation of these disparate
mechanisms yields the correct leading-order result for the physical limit at
\nu = 3 dimensions. After applying this new method to the energy loss problem
in some detail, we then show how it also provides a very short and easy way to
compute the Lamb shift.


title: Solidification pipes: from solder pots to igneous rocks

abstract:
  When a substance that shrinks in volume as it solidifies (for example, lead)
is melted in a container and then cooled, a deep hole is often found in the
center after resolidification. We use a simple model to describe the shape of
the pipe and compare it with experimental results.


title:
Semiempirical charge distribution of clusters in the ion sputtering of
  metal

abstract:
  We propose the generalization of a known established empirically (Wahl W. and
Wucher A. Nucl. Instrum. Meth. B 94, 36(1994)) power law, describing relative
mass-spectra of neutral sputtered clusters, on the cases of arbitrary cluster
charges. The fluctuation mechanism of charge state formation of sputtering
products in the form of large clusters with the number of atoms N > 5 is also
proposed. The simple formula obtained by us has been shown a good agreement
with the experimental data.


title:
Classical Tunneling as the Result of Retardation in Classical
  Electrodynamics: Nonrelativistic Case

abstract:
  In nonrelativistic approximation one-dimensional motion of Sommerfeld sphere
in the case of potential barrier is numerically investigated. The effect of
classical tunneling is confirmed once more - Sommerfeld sphere overcomes the
barrier and finds itself in the forbidden, from classical point of view, area.


title: Symmetry Principles of the Unified Field Theory

abstract:
  The principles of energy, symmetry, entropy, and causality conservation are
discussed in a "Tetrahedron Model" of a conceptually complete "T.O.E.:" "The
charges of matter are the symmetry debts of light" (Noether's Theorem).
Symmetry debts for each force as well as gravitation's conservation roles are
considered. Special attention is given to the weak force. Charge invariance
(including "Lorentz Invariance") and "Noether's Theorem" are seen as keys to
understanding the local action of the forces. A synthesis between the
"Tetrahedron Model" and global vs local gauge symmetry concepts as found in the
"Standard Model" of physics is presented.


title: About Charge Density Wave for Electromagnetic Field-Drive

abstract:
  To generate a propulsive force without propellant and external couplings, it
has been shown that two confined macroscopic and time-varying charge density
waves well separated in space are needed. Here, some physical conditions will
be proposed to support and maintain these particular collective modes of charge
distributions.


title:
The Light Velocity Casimir Effect - Does the Velocity of Light Increase
  when Propagating Between the Casimir Plates?

abstract:
  We propose experiments that might be set up to detect the increase in the
velocity of light in a vacuum in the laboratory frame for photons travelling
between (and perpendicular to) the Casimir plates in a vacuum. The Casimir
plates are two closely spaced, conductive plates, where an attractive force is
observed to exist between the plates called the 'Casimir Force'. We propose
that the velocity of light in a vacuum increases when propagating between two
transparent Casimir Plates. We call this effect the 'Light Velocity Casimir
Effect' or LVC effect. The LVC effect happens because the vacuum energy density
in between the plates is lower than that outside the Casimir plates. The
conductive plates disallow certain frequencies of electrically charged virtual
particles to exist inside the plates, thus lowering the inside vacuum particle
density, compared to the density outside the plates. The reduced (electrically
charged) virtual particle density results in fewer photon scattering events
inside the plates, which should increase the light velocity between the plates
in a vacuum relative to the normal vacuum light speed. A similar effect,
involving light velocity change, occurs when light travels through two
different real material densities; for example when light propagates from water
to air, a process known as optical refraction.


title: A twist in chiral interaction between biological helices

abstract:
  Using an exact solution for the pair interaction potential, we show that
long, rigid, chiral molecules with helical surface charge patterns have a
preferential interaxial angle ~((RH)^1/2)/L, where L is the length of the
molecules, R is the closest distance between their axes, and H is the helical
pitch. Estimates based on this formula suggest a solution for the puzzle of
small interaxial angles in a-helix bundles and in cholesteric phases of DNA.


title:
Residual Symmetries in the Spectrum of Periodically Driven Alkali
  Rydberg States

abstract:
  We identify a fundamental structure in the spectrum of microwave driven
alkali Rydberg states, which highlights the remnants of the Coulomb symmetry in
the presence of a non-hydrogenic core. Core-induced corrections with respect to
the hydrogen spectrum can be accounted for by a perturbative approach.


title:
Unconventional Logic Elements on the Base of Topologically Modulated
  Signals

abstract:
  The paper presents new results in the field of super high-speed and
multi-valued signal processing. Writting digital information into spatial
structures (topological charts) of electromagnetic field pulses allows to use
passive circuits for fulfillment several subpicosecond spatial logical
operations. This is confirmed by analysis of several physical effects in solids
and micron circuits, which influence on time delay of signals. A subpicosecond
circuit for spatially modulated signal switching is considered. An analogy
between electromagnetic mode physics and several aspects of quantum mechanics
is studied. On this base a new digital multi-valued device for spatially
modulated signal processing is suggested and modeled. A conclusion on
possibility to design a new threedimensional architecture of super-density IC
has been made.


title: The Rest Mass of the Hydrogen Atom from First Principles

abstract:
  The rest mass of the hydrogen atom in its ground state is calculated from
first physical principles and elementary geometric considerations.


title: Full Physical Derivation and Meaning of Lorentz Transformation

abstract:
  In the line of thought of Einstein's 1905 paper on relativity, I get a
physical derivation of Lorentz transformation (LT) answering its main criticism
and considerably enlarging the area of applications of the theory of
relativity.


title:
Two-dimensional sideband Raman cooling and Zeeman state preparation in
  an optical lattice

abstract:
  A method of sideband Raman cooling to the vibrational ground state of the
$m=0$ Zeeman sublevel in a far-detuned two-dimensional optical lattice is
proposed. In our scheme, the Raman coupling between vibrational manifolds of
the adjacent Zeeman sublevels is shifted to the red sideband due to the ac
Stark effect induced by a weak pump field. Thus, cooling and optical pumping to
$m=0$ is achieved by purely optical means with coplanar cw laser beams. The
optical lattice and cooling parameters are estimated in the framework of simple
theoretical models. An application of the transverse sideband cooling method to
frequency standards is discussed. Coherent population trapping for the sideband
Raman transitions between the degenerate vibrational levels is predicted.


title: The evolved vacuum model (EVM) of redshifts

abstract:
  A new interpretation of cosmological redshifts is proposed to construct the
evolved-vacuum model of this phenomenon.The physical vacuum was considered to
be a real matter with time-dependent permittivity and permeability. Time
variation of these parameters 10^{-10} per year was shown on the base of
Maxwell's equations and Hubble's law to obey the exponential behavior causing
step-by-step decrease of light velocity with a rate of about 3m/s over 100
years. Cosmological aspects are discussed to explain some features of reality
of the Universe evolution.


title:
Exact solution to the Schr\"{o}dinger equation for the quantum rigid
  body

abstract:
  The exact solution to the Schr\"{o}dinger equation for the rigid body with
the given angular momentum and parity is obtained. Since the quantum rigid body
can be thought of as the simplest quantum three-body problem where the internal
motion is frozen, this calculation method is a good starting point for solving
the quantum three-body problems.


title: Making sense of Physics in the first year of study

abstract:
  We address the question "How do students make sense of Physics from the point
of view of constituting physics knowledge?". A phenomenographic study is
described as a result of which we present six qualitatively different ways in
which students experience the first year of Physics. The variation is analysed
in terms of the structure of experience, the nature of knowlege and an ethical
aspect related to the identification of authority. Three of these ways of
experiencing the first year are considered to be unproductive in terms of
making sense of physics, while the other three support, to an increasing
degree, the formation of a well-grounded physics knowledge object. Implications
for practice are considered.


title: On acoustic cavitation of slightly subcritical bubbles

abstract:
  The classical Blake threshold indicates the onset of quasistatic evolution
leading to cavitation for gas bubbles in liquids. When the mean pressure in the
liquid is reduced to a value below the vapor pressure, the Blake analysis
identifies a critical radius which separates quasistatically stable bubbles
from those which would cavitate. In this work, we analyze the cavitation
threshold for radially symmetric bubbles whose radii are slightly less than the
Blake critical radius, in the presence of time-periodic acoustic pressure
fields. A distinguished limit equation is derived that predicts the threshold
for cavitation for a wide range of liquid viscosities and forcing frequencies.
This equation also yields frequency-amplitude response curves. Moreover, for
fixed liquid viscosity, our study identifies the frequency that yields the
minimal forcing amplitude sufficient to initiate cavitation. Numerical
simulations of the full Rayleigh-Plesset equation confirm the accuracy of these
predictions. Finally, the implications of these findings for acoustic pressure
fields that consist of two frequencies will be discussed.


title: Polarized Electromagnetic Radiation from Spatially Correlated Sources

abstract:
  We consider the effect of spatial correlations on sources of polarized
electromagnetic radiation. The sources, assumed to be monochromatic, are
constructed out of dipoles aligned along a line such that their orientation is
correlated with their position. In one representative example, the dipole
orientations are prescribed by a generalized form of the standard von Mises
distribution for angular variables such that the azimuthal angle of dipoles is
correlated with their position. In another example the tip of the dipole vector
traces a helix around the symmetry axis of the source, thereby modelling the
DNA molecule. We study the polarization properties of the radiation emitted
from such sources in the radiation zone. For certain ranges of the parameters
we find a rather striking angular dependence of polarization. This may find
useful applications in certain biological systems as well as in astrophysical
sources.


title: Monte Carlo implementation of supercoiled double-stranded DNA

abstract:
  Metropolis Monte Carlo simulation is used to investigate the elasticity of
torsionally stressed double-stranded DNA, in which twist and supercoiling are
incorporated as a natural result of base-stacking interaction and backbone
bending constrained by hydrogen bonds formed between DNA complementary
nucleotide bases. Three evident regimes are found in extension versus torsion
and/or force versus extension plots: a low-force regime in which over- and
underwound molecules behave similarly under stretching; an intermediate-force
regime in which chirality appears for negatively and positively supercoiled DNA
and extension of underwound molecule is insensitive to the supercoiling degree
of the polymer; and a large-force regime in which plectonemic DNA is fully
converted to extended DNA and supercoiled DNA behaves quite like a torsionless
molecule. The striking coincidence between theoretic calculations and recent
experimental measurement of torsionally stretched DNA [Strick et al., Science
{\bf 271}, 1835 (1996), Biophys. J. {\bf 74}, 2016 (1998)] strongly suggests
that the interplay between base-stacking interaction and permanent
hydrogen-bond constraint takes an important role in understanding the novel
properties of elasticity of supercoiled DNA polymer.

categories: physics.bio-ph cond-mat.soft physics.chem-ph physics.comp-ph q-bio


title:
Enhanced Phase Space Diffusion due to Chaos in Relativistic Electron-
  Whistler Mode Wave Particle Interactions in Planetary Magnetospheres

abstract:
  The chaotic interaction between electrons and whistler mode waves has been
shown to provide a mechanism for enhanced diffusion in phase space. Pitch angle
diffusion is relevant for the scattering of electrons into the loss cones, thus
providing a source for auroral precipitating electrons. A single whistler mode
wave propagating parallel to the background magnetic field has resonance with
the electrons but the process is not stochastic. The presence of a second,
oppositely directed whistler wave has been shown previously to introduce
stochasticity into the system, thus enhancing phase space diffusion. Here we
generalise previous work to include relativistic effects. The full relativistic
Lorentz equations are solved numerically to permit application to a more
extensive parameter space. We consider parameters scaled to intrinsic planetary
magnetospheres, for electron populations with 'pancake' velocity distributions
i.e. large anisotropies in velocity space. We show that the diffusion is rapid,
occuring on timescales of the order of tens of electron gyroperiods, and is
strongly sensitive to the wave amplitude, the wave frequency and the
perpendicular velocity. Using Voyager 1 data we give an estimate of the
whistler wave amplitude in the Io torus at Jupiter and show that the two
whistler mechanism produces pitch angle diffusion of up to 10 degrees from an
initial pancake distribution, on millisecond timescales.


title: Spin-Lattice Relaxation in Metal-Organic Platinum(II) Complexes

abstract:
  The dynamics of spin-lattice relaxation (slr) of metal-organic Pt(II)
compounds is studied. Often, such systems are characterized by pronounced
zero-field splittings (zfs) of the lowest-lying triplets. Previous expressions
for the Orbach slr process do not allow to treat such splitting patterns
properly. We discuss the behavior of a modified Orbach expression for a model
system and present results of a fit of the temperature dependence of the
spin-lattice relaxation rate of Pt(2-thpy)$_2$ based on the modified
expression.


title: Mixtures of Gaussian process priors

abstract:
  Nonparametric Bayesian approaches based on Gaussian processes have recently
become popular in the empirical learning community. They encompass many
classical methods of statistics, like Radial Basis Functions or various
splines, and are technically convenient because Gaussian integrals can be
calculated analytically. Restricting to Gaussian processes, however, forbids
for example the implemention of genuine nonconcave priors. Mixtures of Gaussian
process priors, on the other hand, allow the flexible implementation of complex
and situation specific, also nonconcave "a priori" information. This is
essential for tasks with, compared to their complexity, a small number of
available training data. The paper concentrates on the formalism for Gaussian
regression problems where prior mixture models provide a generalisation of
classical quadratic, typically smoothness related, regularisation approaches
being more flexible without having a much larger computational complexity.


title: On the Viscosity of Emulsions

abstract:
  Combining direct computations with invariance arguments, Taylor's
constitutive equation for an emulsion can be extrapolated to high shear rates.
We show that the resulting expression is consistent with the rigorous limits of
small drop deformation and that it bears a strong similarity to an a priori
unrelated rheological quantity, namely the dynamic (frequency dependent) linear
shear response. More precisely, within a large parameter region the nonlinear
steady-state shear viscosity is obtained from the real part of the complex
dynamic viscosity, while the first normal stress difference is obtained from
its imaginary part. Our experiments with a droplet phase of a binary polymer
solution (alginate/caseinate) can be interpreted by an emulsion analogy. They
indicate that the predicted similarity rule generalizes to the case of
moderately viscoelastic constituents that obey the Cox-Merz rule.


title: The Variant Principle

abstract:
  Based on the principle of causality, I advance a new principle of variation
and try to use it as the most general principle for research into laws of
nature.


title:
High sensitivity two-photon spectroscopy in a dark optical trap, based
  on electron shelving

abstract:
  We propose a new spectroscopic method for measuring weak transitions in cold
and trapped atoms, which exploits the long interaction times and tight
confinement offered by dark optical traps together with an electron shelving
technique to achieve extremely high sensitivity. We demonstrate our scheme by
measuring a 5S_{1/2}-> 5D_{5/2} two-photon transition in cold Rb atoms trapped
in a new single-beam dark optical trap, using an extremely weak probe laser
power of 25 micro-Watt. We were able to measure transitions with as small
excitation rate as 0.09 sec^(-1).


title:
A simple scaling law between the total energy of a free atom and its
  atomic number

abstract:
  A simple, approximate relation is found between the total energy of a free
atom and its atomic number: E ~= -Z^{2.411}. The existence of this index is
inherent in the Coulomb and many-body nature of the electron-electron
interaction in the atomic system and cannot be fabricated from the existing
fundamental physical constants.

categories: physics.chem-ph physics.atom-ph physics.comp-ph physics.pop-ph quant-ph


title: Relativistic Kinematic Anomaly

abstract: This paper has been withdrawn


title:
Bayesian Field Theory: Nonparametric Approaches to Density Estimation,
  Regression, Classification, and Inverse Quantum Problems

abstract:
  Bayesian field theory denotes a nonparametric Bayesian approach for learning
functions from observational data. Based on the principles of Bayesian
statistics, a particular Bayesian field theory is defined by combining two
models: a likelihood model, providing a probabilistic description of the
measurement process, and a prior model, providing the information necessary to
generalize from training to non-training data. The particular likelihood models
discussed in the paper are those of general density estimation, Gaussian
regression, clustering, classification, and models specific for inverse quantum
problems. Besides problem typical hard constraints, like normalization and
positivity for probabilities, prior models have to implement all the specific,
and often vague, "a priori" knowledge available for a specific task.
Nonparametric prior models discussed in the paper are Gaussian processes,
mixtures of Gaussian processes, and non-quadratic potentials. Prior models are
made flexible by including hyperparameters. In particular, the adaption of mean
functions and covariance operators of Gaussian process components is discussed
in detail. Even if constructed using Gaussian process building blocks, Bayesian
field theories are typically non-Gaussian and have thus to be solved
numerically. According to increasing computational resources the class of
non-Gaussian Bayesian field theories of practical interest which are
numerically feasible is steadily growing. Models which turn out to be
computationally too demanding can serve as starting point to construct easier
to solve parametric approaches, using for example variational techniques.

categories: physics.data-an adap-org cond-mat.dis-nn nlin.AO


title: The Universe's Evolution

abstract:
  Based on a new theory of causality [1] and its development to the theory of
the Universe [2], we show, in this paper, new ideas for building a theory of
everything.


title: The Equation of Causality

abstract:
  We research the natural causality of the Universe. We find that the equation
of causality provides very good results on physics. That is our first endeavour
and success in describing a quantitative expression of the law of causality.
Hence, our theoretical point suggests ideas to build other laws including the
law of the Universe's evolution.


title: Causality: The Nature of Everything

abstract:
  We pursue research leading towards the nature of causality in the universe.
We establish the equation of the universe's evolution from the universe-state
function and its series expansion, in which causes and effects connect together
to construct a linked chain of causality. And the equation of causality [1] is
rederived. Therefrom, our theory informs the progress of the universe and,
simulaneously, a law that presents everywhere. Furthermore, we lay some
foundations for a new mathematical phrasing of the movement of physics. That is
the life-like mathematics - a mathematics full of life.


title: Spinning jets

abstract:
  A fluid jet with a finite angular velocity is subject to centripetal forces
in addition to surface tension forces. At fixed angular momentum, centripetal
forces become large when the radius of the jet goes to zero. We study the
possible importance of this observation for the pinching of a jet within a
slender jet model. A linear stability analysis shows the model to break down at
low viscosities. Numerical simulations indicate that angular momentum is
expelled from the pinch region so fast that it becomes asymptotically
irrelevant in the limit of the neck radius going to zero.


title: Electrodynamic forces in elastic matter

abstract:
  A macroscopic theory for the dynamics of elastic, isotropic matter in
presence of electromagnetic fields is proposed here. We avail of Gordon's
general relativistic derivation of Abraham's electromagnetic energy tensor as
starting point. The necessary description of the elastic and of the inertial
behaviour of matter is provided through a four dimensional generalisation of
Hooke's law, made possible by the introduction of a four dimensional
``displacement'' vector. As intimated by Nordstroem, the physical origin of
electrostriction and of magnetostriction is attributed to the change in the
constitutive equation of electromagnetism caused by the deformation of matter.
The part of the electromagnetic Lagrangian that depends on that deformation is
given explicitly for the case of an isotropic medium and the resulting
expression of the electrostrictive force is derived, thus showing how more
realistic equations of motion for matter subjected to electromagnetic fields
can be constructed.


title:
Marcatili's Lossless Tapers and Bends: an Apparent Paradox and its
  Solution

abstract:
  Numerical results based on an extended BPM algorithm indicate that, in
Marcatili's lossless tapers and bends, through-flowing waves are drastically
different from standing waves. The source of this surprising behavior is
inherent in Maxwell's equations. Indeed, if the magnetic field is correctly
derived from the electric one, and the Poynting vector is calculated, then the
analytical results are reconciled with the numerical ones. Similar
considerations are shown to apply to Gaussian beams in free space.


title: Dynamic Fitness Landscapes in Molecular Evolution

abstract:
  We study self-replicating molecules under externally varying conditions.
Changing conditions such as temperature variations and/or alterations in the
environment's resource composition lead to both non-constant replication and
decay rates of the molecules. In general, therefore, molecular evolution takes
place in a dynamic rather than a static fitness landscape. We incorporate
dynamic replication and decay rates into the standard quasispecies theory of
molecular evolution, and show that for periodic time-dependencies, a system of
evolving molecules enters a limit cycle for $t\to\infty$. For fast periodic
changes, we show that molecules adapt to the time-averaged fitness landscape,
whereas for slow changes they track the variations in the landscape arbitrarily
closely. We derive a general approximation method that allows us to calculate
the attractor of time-periodic landscapes, and demonstrate using several
examples that the results of the approximation and the limiting cases of very
slow and very fast changes are in perfect agreement. We also discuss landscapes
with arbitrary time dependencies, and show that very fast changes again lead to
a system that adapts to the time-averaged landscape. Finally, we analyze the
dynamics of a finite population of molecules in a dynamic landscape, and
discuss its relation to the infinite population limit.

categories: physics.bio-ph adap-org cond-mat.soft cond-mat.stat-mech nlin.AO q-bio.PE


title: Atomic collisions and sonoluminescence

abstract:
  We consider inelastic collisions between atoms of different kinds as a
potential source of photons in the sonoluminescence phenomena. We estimate the
total energy emitted in one flash and the shape of the spectrum and find a
rough agreement between the results of our calculation and the experimental
data. We conclude that the atomic collisions might be a candidate for the
light-emitting mechanism for sonoluminescence and discuss the implications.


title: A New Hypothesis for the Vertical Distribution of Atmospheric Aerosols

abstract:
  A simple model which can explain the observed vertical distribution and size
spectrum of atmospheric aerosol has been proposed. The model is based on a new
physical hypothesis for the vertical mass exchange between the troposphere and
the stratosphere. The vertical mass excange takes place through a gravity wave
feedback mechanism. There is a close agreement between the model predicted
aerosol distribution and size spectrum and the observed distributions.


title: Negative Observations in Quantum Mechanics

abstract:
  In quantum mechanics, it is possible to make observations that affect
physical entities without there being a physical interaction between the
observer and the physical entity measured. Epstein (1945) and Renninger (1960)
discussed this situation, and Renninger called this type of observation a
"negative observation." Empirical research on electron shelving supports the
possibility of negative observations (Bergquist, Hulet, Itano, and Wineland,
1986; Nagourney, Sandberg, and Dehmelt, 1986; Sauter, Neuhauser, Blatt, and
Toschek, 1986). Two scenarios are presented that emphasize the role of human
observation in negative observations. The first is modeled after the two hole
gedankenexperiments of Feynman, Leighton, and Sands (1965) and portrays
negative observations in a non-technical manner. The second scenario allows for
quantifying the affect on physical entities of negative observations in a
simple fashion. In addition, various issues related to negative observation are
discussed, including an objection that might be raised. The Schrodinger cat
gedankenexperiment is discussed briefly as well.


title:
Effect of Subphase Ca++ Ions on the Viscoelastic Properties of Langmuir
  Monolayers

abstract:
  It is known that the presence of cations like Ca++ or Pb++ in the water
subphase alters the pressure-area isotherms for fatty acid monolayers. The
corresponding lattice constant changes have been studied using x-ray
diffraction. Reflection-absorption spectroscopy has been used to probe the
chemical composition of the film. We report on the first measurements of the
time evolution of the shear viscosity of arachidic acid monolayers in the
presence of Ca++ ions in the subphase. We find that the introduction of Ca++
ions to the water subphase results in an increase of the film's viscosity by at
least three orders of magnitude. This increase occurs in three distinct stages.
First, there is a rapid change in the viscosity of up to one order of
magnitude. This is followed by two periods, with very different time constants,
of a relatively slow increase in the viscosity over the next 10 or more hours.
The corresponding time constants for this rise decrease as either the subphase
pH or Ca++ concentration is increased.


title:
An elementary quantum mechanics calculation for the Casimir effect in
  one dimension

abstract:
  We obtain the Casimir effect for the massless scalar field in one dimension
based on the analogy between the quantum field and the continuum limit of an
infinite set of coupled harmonical oscillators.


title: Stopping of ion beam in a temperature anisotropic magnetized plasma

abstract:
  Using the dielectric theory for a weakly coupled plasma we investigate the
stopping power of the ion in a temperature anisotropic magnetized electron
plasma. The analysis is based on the assumption that the energy variation of
the ion is much less than its kinetic energy. The obtained general expression
for stopping power is analyzed for weak and strong magnetic fields (i.e., for
the electron cyclotron frequency less than and greater than the plasma
frequency), and for low and high ion velocities. It is found that the friction
coefficient contains, in addition to the usual velocity independent friction
coefficient, an anomulous term which diverges logarithmically as the projectile
velocity approaches zero. The physical origin of this anomulous term is the
coupling between the cyclotron motion of the electrons and the long-wave
length, low-frequency fluctuations produced by the projectile ion.


title:
Electric microfield distribution in two-component plasmas. Theory and
  Simulations

abstract:
  The distribution of the electric microfield at a charged particle moving in a
two-component plasma is calculated. The theoretical approximations are obtained
via the parameter integration technique and using the screened pair
approximation for the generalized radial distribution function. It is shown
that the two-component plasma microfield distribution shows a larger
probability of high microfield values than the corresponding distribution of
the commonly used OCP model. The theory is checked by quasiclassical
molecular-dynamics simulations. For the simulations a corrected Kelbg
pseudopotential has been used.


title: Classical approaches to Higgs mechanism

abstract:
  The standard approach to Higgs mechanism is based on the existence of unitary
gauge but, unfortunately, it does not come from a coordinate change in the
configuration space of the initial model and actually defines a new dynamical
system. So, it is a questionable approach to the problem but it is shown here
that the final result could still make sense as a Marsden-Weinstein reduced
system. (This reduction can be seen as completely analogous to the procedure of
obtaining the "centrifugal" potential in the classical Kepler problem.) It is
shown that in the standard linearization approximation of the Coulomb gauged
Higgs model geometrical constraint theory offers an explanation of the Higgs
mechanism because solving of the Gauss law constraint leads to different
physical submanifolds which are not preserved by the action of the (broken)
global U(1) group.


title: Mathematical Model of Attraction and Repulsion Forces

abstract:
  Here I introduce the model in an attempt to describe the underlying reasons
of attraction and repulsion forces between two physical bodies. Both electrical
and gravitational forces are considered. Results are based on the technique
developed in the Dual Time-Space Model of Wave Propagation.


title: About Perpetuum Mobile without Emotions

abstract:
  One of the oldest science problems - possibility of the perpetuum mobile is
discussed. The interest to this problem was provoke a result, published in J.
Low Temp.Phys. 112, 227 (1998); cond-mat/9811148, which contradicts to the
second law of thermodynamics. According to this result, the thermal
fluctuations can induce a voltage with direct component in a inhomogeneous
superconducting ring at an unaltered temperature corresponded to the resistive
transition of the ring segment with the lowest critical temperature. This
result arises from obvious statements: 1) the switching of a ring segment
$l_{b}$ into and out of the normal state, while the rest of the ring (segment
$l_{a}$) remains superconducting, can induced a voltage with dc component (It
is shown that, in spite of the wide spread opinion, this statement is correct
because the superconductivity is a macroscopic quantum phenomena); 2) the
thermal fluctuations switch the mesoscopic ring segment $l_{b}$ with lowest
critical temperature $T_{sb}$ into and out of the normal state at $T \simeq
T_{sb}$, while the rest of the ring remains superconducting if $T_{sa} > T
\simeq T_{sb}$. In order to resolve the contradiction between these obvious
statements and the second law of thermodynamics a possibility of the second
order perpetuum mobile is considered theoretically. It is shown that from two
type of the perpetuum mobile, only type "b" and only in quantum systems is
possible. According to the presented interpretation, the total entropy, as the
measure of the chaos, may be systematically reduced in some quantum system
because a "switching" between the classical and quantum mechanics is possible.
Instruction for the making of the perpetuum mobile is enclosed.


title: Mechanisms of positron annihilation on molecules

abstract:
  The aim of this work is to identify the mechanisms responsible for very large
rates and other peculiarities observed in low-energy positron annihilation on
molecules. The two mechanisms considered are: (i) Direct annihilation of the
incoming positron with one of the molecular electrons. This mechanism dominates
for atoms and small molecules. I show that its contribution to the annihilation
rate can be related to the positron elastic scattering cross section. This
mechanism is characterized by strong energy dependence of the annihilation rate
at small positron energies if a low-lying virtual level or a weakly bound state
exists for the positron. (ii) Resonant annihilation, which takes place when the
positron undergoes resonant capture into a vibrationally excited quasibound
state of the positron-molecule complex. This mechanism dominates for larger
molecules capable of forming bound states with the positron. For this mechanism
the energy-averaged annihilation rate is proportional to the level density of
the positron-molecule complex, which is basically determined by the spectrum of
molecular vibrational states populated in the positron capture. For
room-temperature positrons this mechnism can produce annihilation rates up to 5
orders of magnitude greater than the first one. Its contribution is inversely
proportional to the positron momentum at small positron energies.


title: Comment on a Tonomura Experiment : Locality of the Vector Potential

abstract:
  Three predictions for additional tests in a Tonomura experiment: 1,2: The
Fresnel frin-ges displayed outside and inside the geometric shadow of a
toroidal magnet should subsist intact, the ones if the others are masked, and
vice versa ; 3 : Placing the registering film just before the magnet and thus
uncovering the entire fringe pattern should display the curved fringes
connecting the outer and inner straight ones. Physicality of the vector
potential expressed in the source adhering gauge will thus be unequivocally
proved.


title:
A 'New Formula' to Provide the Compatibility between the Special Theory
  of Relativity (STR), Black Holes and Strings

abstract:
  This paper describes a 'New Formula' in place of Einstein's Famous Formula
(EFF) to provide the compatibility between the Special Theory of Relativity
(STR), black holes and strings. The 'New Formula' can also predict and describe
the space-time singularities without the distribution of mass and energy.
According to the 'New Formula', any particle can reach to and exceed the speed
of light. The EFF is only valid and applicable in the vacuum (the mediums which
have low current density: outside string, outside black hole), but is not valid
and applicable for inside string and inside black hole including space-time
singularities. However, the 'New Formula' is valid and applicable in all
mediums including inside string and inside black hole.


title:
Detection of a flow induced magnetic field eigenmode in the Riga dynamo
  facility

abstract:
  In an experiment at the Riga sodium dynamo facility, a slowly growing
magnetic field eigenmode has been detected over a period of about 15 seconds.
For a slightly decreased propeller rotation rate, additional measurements
showed a slow decay of this mode. The measured results correspond satisfactory
with numerical predictions for the growth rates and frequencies.

categories: physics.flu-dyn astro-ph physics.gen-ph physics.geo-ph physics.plasm-ph


title: Relation between the Inertial Mass and the Gravity Mass

abstract:
  This article shows the relation between the inertial mass and the gravity
mass. The gravity field can propagate only with a limited velocity. Therefore
the Helmholz equation is introduced for the gravity potential. The analysis of
the Helmholz equation leads to the "Maxwell equations" for the gravity field.
The dualism between the electricity and the gravity shows that the structure of
the own gravity field of a mass object is responsible for his inertial mass.
Additional all dual electric field values are described in the gravity field
notation.


title: Calculation of parity and time invariance violation in the radium atom

abstract:
  Parity (P) and time (T) invariance violating effects in the Ra atom are
strongly enhanced due to close states of opposite parity, the large nuclear
charge Z and the collective nature of P,T-odd nuclear moments. We have
performed calculations of the atomic electric dipole moments (EDM) produced by
the electron EDM and the nuclear magnetic quadrupole and Schiff moments. We
have also calculated the effects of parity non-conservation produced by the
nuclear anapole moment and the weak charge. Our results show that as a rule the
values of these effects are much larger than those considered so far in other
atoms (enhancement is up to 10^5 times).


title: The Bag Model of Nuclei

abstract:
  The basic assumptions and the general results of our bag model for nuclei are
presented in detail. Nuclei are considered in a unified integration of the mean
field theory and the MIT bag model


title:
Radiation of mixed layer near-inertial oscillations into the ocean
  interior

abstract:
  The radiation from the mixed layer into the interior of the ocean of
near-inertial oscillations excited by a passing storm in the presence of the
beta effect is reconsidered as an initial-value problem. Making use of the fact
that the mixed layer depth is much smaller than the total depth of the ocean,
the solution is obtained in the limit of an ocean that is effectively
infinitely deep. For a uniform initial condition, analytical results for the
velocity, horizontal kinetic energy density and fluxes are obtained. The
resulting decay of near-inertial mixed layer energy in the presence of the beta
effect occurs on a timescale similar to that observed.


title: Hydrogen atom in a spherical well: linear approximation

abstract:
  We discuss the boundary effects on a quantum system by examining the problem
of a hydrogen atom in a spherical well. By using an approximation method which
is linear in energy we calculate the boundary corrections to the ground-state
energy and wave function. We obtain the asymptotic dependence of the
ground-state energy on the radius of the well.


title: Stabilization not for certain and the usefulness of bounds

abstract:
  Stabilization is still a somewhat controversial issue concerning its very
existence and also the precise conditions for its occurrence. The key quantity
to settle these questions is the ionization probability, for which hitherto no
computational method exists which is entirely agreed upon. It is therefore very
useful to provide various consistency criteria which have to be satisfied by
this quantity, whose discussion is the main objective of this contribution. We
show how the scaling behaviour of the space leads to a symmetry in the
ionization probability, which can be exploited in the mentioned sense.
Furthermore, we discuss how upper and lower bounds may be used for the same
purpose. Rather than concentrating on particular analytical expressions we
obtained elsewhere for these bounds, we focus in our discussion on the general
principles of this method. We illustrate the precise working of this procedure,
its advantages, shortcomings and range of applicability. We show that besides
constraining possible values for the ionization probability these bounds, like
the scaling behaviour, also lead to definite statements concerning the physical
outcome. The pulse shape properties which have to be satitisfied for the
existence of asymptotical stabilization is the vanishing of the total classical
momentum transfer and the total classical displacement and not smoothly
switched on and off pulses. Alternatively we support our results by general
considerations in the Gordon-Volkov perturbation theory and explicit studies of
various pulse shapes and potentials including in particular the Coulomb- and
the delta potential.


title:
On the gravitational field of a sphere of incompressible fluid according
  to Einstein's theory

abstract:
  Communication by K. Schwarzschild to the Prussian Academy of Sciences,
dealing with the gravitational field of a sphere of incompressible fluid.


title: Kalman Filter Track Fits and Track Breakpoint Analysis

abstract:
  We give an overview of track fitting using the Kalman filter method in the
NOMAD detector at CERN, and emphasize how the wealth of by-product information
can be used to analyze track breakpoints (discontinuities in track parameters
caused by scattering, decay, etc.). After reviewing how this information has
been previously exploited by others, we describe extensions which add power to
breakpoint detection and characterization. We show how complete fits to the
entire track, with breakpoint parameters added, can be easily obtained from the
information from unbroken fits. Tests inspired by the Fisher F-test can then be
used to judge breakpoints. Signed quantities (such as change in momentum at the
breakpoint) can supplement unsigned quantities such as the various chisquares.
We illustrate the method with electrons from real data, and with Monte Carlo
simulations of pion decays.


title:
Cantorian Fractal Space-Time Fluctuations in Turbulent Fluid Flows and
  the Kinetic Theory of Gases

abstract:
  Fluid flows such as gases or liquids exhibit space-time fluctuations on all
scales extending down to molecular scales. Such broadband continuum
fluctuations characterise all dynamical systems in nature and are identified as
selfsimilar fractals in the newly emerging multidisciplinary science of
nonlinear dynamics and chaos. A cell dynamical system model has been developed
by the author to quantify the fractal space-time fluctuations of atmospheric
flows. The earth's atmosphere consists of a mixture of gases and obeys the gas
laws as formulated in the kinetic theory of gases developed on probabilistic
assumptions in 1859 by the physicist James Clerk Maxwell. An alternative theory
using the concept of fractals and chaos is applied in this paper to derive
these fundamental gas laws.


title:
Relativistic semiclassical approach in strong-field nonlinear
  photoionization

abstract:
  Nonlinear relativistic ionization phenomena induced by a strong laser
radiation with elliptically polarization are considered. The starting point is
the classical relativistic action for a free electron moving in the
electromagnetic field created by a strong laser beam. The application of the
relativistic action to the classical barrier-suppression ionization is briefly
discussed. Further the relativistic version of the Landau-Dykhne formula is
employed to consider the semiclassical sub-barrier ionization. Simple
analytical expressions have been found for: (i) the rates of the strong-field
nonlinear ionization including relativistic initial and final state effects;
(ii) the most probable value of the components of the photoelectron final state
momentum; (iii) the most probable direction of photoelectron emission and (iv)
the distribution of the photoelectron momentum near its maximum value.


title: In search of fundamental laws

abstract:
  One of the main activities in science teaching, and in particular in Physics
teaching, is not only the discussion of both modern problems and problems which
solution is an urgent matter. It means that the picture of an active and alive
science should be transmitted to the students, mainly to the College students.
A central point in this matter is the issue which characterizes the Fundamental
Laws of Nature. In this work we emphasize that this sort of laws may exist in
areas which are different from those usually considered. In this type of
discussion it is neither possible nor desirable to avoid the historical
perspective of the scientific development.


title: A Model of Convergent Extension in Animal Morphogenesis

abstract:
  In this paper we argue that the pattern of cell movements in the
morphogenetic process known as convergent extension can be understood as a
energy minimization process, provided the cell-cell adhesive energy has a
certain kind of anisotropy. This single simple property is sufficient cause for
the type of cell elongation, alignment, and intercalation of a cellular array
that is the characteristic of convergent extension. We describe the type of
anisotropy required. We show that the final aspect ratio of the array of cells
is independent of the initial configuration and of the degree of cell
elongation. We find how it depends on the anisotropy.


title: Semiclassical dynamics and time correlations in two-component plasmas

abstract:
  The semiclassical dynamics of a charged particle moving in a two-component
plasma is considered using a corrected Kelbg pseudopotential. We employ the
classical Nevanlinna-type theory of frequency moments to determine the velocity
and force autocorrelation functions. The constructed expressions preserve the
exact short and long-time behavior of the autocorrelators. The short-time
behavior is characterized by two parameters which are expressable through the
plasma static correlation functions. The long-time behavior is determined by
the self-diffusion coefficient. The theoretical predictions are compared with
the results of semiclassical molecular dynamics simulation.


title: Exploring the physics of the relativistic energy-momentum relationship

abstract:
  Considerations on the complementary time-dependent coordinate transformations
emboding Lorentz transformation (LT) show that the relativistic energy-momentum
relationship, implicitly the relativistic mass and energy, do not depend on the
square root appearing in LT, being associated to the absolute motion of a
particle and related to its inner structure. Results concerning the concept of
operational theory and its application to the electromagnetic and gravitational
field theories, as well as to the quantum mechanics are given in appendixes.


title:
Dynamic structure factor and collective excitations of neutral and
  Coulomb fluids

abstract:
  The dynamic sructure factor as the basic quantity describing the collective
excitations in a fluid is considered. We consider the cases of neutral and
Coulombic fluids. The classical method of moments is applied to construct the
dynamic structure factor satisfying all known sum rules. An interpolational
formula is found which expresses the dynamic characteristics of a classical or
quantum fluid system in terms of its static correlation parameters. The
analytical results based on the theory of moments are compared with Molecular
dynamics data for various model systems.


title:
A Monte Carlo code for full simulation of a transition radiation
  detector

abstract:
  A full simulation of a transition radiation detector (TRD) based on the
GEANT, GARFIELD, MAGBOLTZ and HEED codes has been developed. This simulation
can be used to study and develop TRD for high energy particle identification
using either the cluster counting or the total charge measurement method. In
this article it will be also shown an application of this simulation to the
discrimination of electrons from hadrons in beams of momentum of few GeV/c or
less, assuming typical TRD configuration, namely radiator-detector modules.


title: DNA transport by a micromachined Brownian ratchet device

abstract:
  We have micromachined a silicon-chip device that transports DNA with a
Brownian ratchet that rectifies the Brownian motion of microscopic particles.
Transport properties for a DNA 50mer agree with theoretical predictions, and
the DNA diffusion constant agrees with previous experiments. This type of
micromachine could provide a generic pump or separation component for DNA or
other charged species as part of a microscale lab-on-a-chip. A device with
reduced feature size could produce a size-based separation of DNA molecules,
with applications including the detection of single nucleotide polymorphisms.


title:
Relativistic photoelectron spectra in the ionization of atoms by
  elliptically polarized light

abstract:
  Relativistic tunnel ionization of atoms by intense, elliptically polarized
light is considered. The relativistic version of the Landau-Dykhne formula is
employed. The general analytical expression is obtained for the relativistic
photoelectron spectra. The most probable angle of electron emission, the
angular distribution near this angle, the position of the maximum and the width
of the energy spectrum are calculated. In the weak field limit we obtain the
familiar non-relativistic results. For the case of circular polarization our
analytical results are in agreement with recent derivations of Krainov [V.P.
Krainov, J. Phys. B, {\bf 32}, 1607 (1999)].