title: Laser Excitation of Wakefields in a Parabolic Plasma Channel

abstract:
  A Gaussian laser pulse with a square profile in time propagating in a
parabolic plasma channel, exerts a ponderomotive force on electrons that drives
a large amplitude electrostatic wake potential phi. An analytic solution for
phi is possible when a characteristic relation is fulfilled. For pulse duration
tau ~ 9 tau_p / 4, where tau_p is the plasma period, the plasma wake potential
on the axis is twice the ponderomotive potential phi_0.


title: Efficient Plasma Heating by Radiofrequency

abstract:
  We propose an efficient mechanism to heat a plasma by an intense microwave
field solving the equation of ion motion in a wave field and a constant
magnetic field in a large coupling regime. The mechanism does not relies
explicitly on stochastic motion and is able to increase the ion velocity by
several magnitude orders. Known thresholds for the onset of stochastic motion
are also obtained.


title: Dispersion managed mode-locking dynamics in a Ti:Sapphire laser

abstract:
  We present what is to our knowledge the most complete 1-D numerical analysis
of the evolution and the propagation dynamics of an ultrashort laser pulse in a
Ti:Sapphire laser oscillator. This study confirms the dispersion managed model
of mode-locking, and emphasizes the role of the Kerr nonlinearity in generating
mode-locked spectra with a smooth and well-behaved spectral phase. A very good
agreement with preliminary experimental measurements is found.


title:
Nonlinear Interactions of Gravitational Wave with Matter in
  Magnetic-type Maxwell-Vlasov Description

abstract:
  The interactions of gravitational waves with interstellar matter, dealing
with resonant wave-particle and wave-wave interactions, are considered on the
basis of magnetic-type Maxwell-Vlasov equations. It is found that the behavior
of the fields, involving the "gravitoelectromagnetic" or "GEM " fields, the
perturbed density field and self-generated gravitomagnetic field with low
frequency,can be described by the nonlinear coupling equations Eqs.
(6.10)-(6.12). Numerical results show that they may collapse. In other words,
due to self-condensing, a stronger GME fields could be produced; and they could
appear as the gravitational waves with high energy reaching on Earth. In this
case, Weber's results, perhaps, are acceptable.


title: Formulating Initial and Boundary Effects for Maxwell Equations

abstract:
  In classical treatment of Maxwell equations, the initial and boundary
conditions are introduced by mathematical consideration rather than strictly
using the Maxwell equations. As a result, the initial and boundary conditions
are not logic consistent with the Maxwell equations. In fact, the boundary
problem of classical Maxwell equations is not solvable for general cases, if
the whole boundary fields are given. This problem is caused by implying the
divergence and the curl of a vector have no relations during introducing the
boundary condition. This research introduces new ideas and formulations to
solve this problem. The research shows that based on Chen S-R decomposition of
a rank-two tensor, this logical un-consistency can be discarded and, as a
consequence, the classical Maxwell equations are reformulated. According to the
reformulated Maxwell equations, the initial condition and boundary condition
have global effects. As an example, the London equations for superconductors
are deduced.


title:
Non-radiating and radiating configurations driven by left-handed
  metamaterials

abstract:
  It is shown that a pair of identical emitters (e.g. wire dipole antennas) in
the focal points of a disc, made of left-handed metamaterial (a "perfect"
lens), form a non-radiating electromagnetic configuration. The emitters are fed
with voltages of equal magnitude and pi-out-of-phase. Detailed
finite-difference time-domain (FDTD) modeling shows that there are
non-propagating electromagnetic fields generated - fields that remain confined
within the region between the emitters and the lens. The energy balance of the
system shows that the radiation resistance of the system is very low. This
means that the input power is converted to heat in the volume of the lens and
only a small fraction of it is radiated. The system performance shows that
disturbing the configuration of the non-propagating electromagnetic fields with
the presence of an externally introduced object stimulates radiation. This
suggests possible detector applications. In-phase feeding voltages are also
studied with the consequence that the radiation resistance of the antennae is
increased.


title:
Analyze of multistage transfer orbit to reach the GEO orbit in a
  rotational symmetric gravitational field

abstract:
  Placing satellites in geostationary obital (GEO) is propellant exigeant. It
requires large propellant consumption that will take a large part of the total
mass. Hence the interest is reduce the mass of propellant loaded both in the
rocket and the satellite. Both for improving selection of transfer orbits and
propellant.
  In this paper we give a reiew of analysis of launching of satellite to GEO
using multistage transfer orbit in order to reduce the mass of propellant.
Making this analysis complete, the effect of the general relativity regarding
elliptical transfer orbit and its potensial utilization will be briefly
reviewed.


title: Proof that quantum mechanics is internally inconsistent on antihydrogen

abstract:
  Quantum mechanics (QM) theoretically forbids natural H-antiH interactions
because of annihilation in the Dirac sense. But in practice, ab initio QM
relies explicitly on HantiH attraction, which it theoretically forbids, to
arrive at attractive forces in the molecular hydrogen cation, given away by the
cusp in its PEC (potential energy curve) at exactly 1,06 Angstrom. This
internal inconsistency in QM is easily removed by lifting its irrational ban on
natural antihydrogen.


title: Universe creation on a computer

abstract:
  The purpose of this paper is to provide an account of the epistemology and
metaphysics of universe creation on a computer.


title: Cerenkov Emission by Neutral Particles in Gravitoelectro-magnetic Fields

abstract:
  It is shown that under the post-Newtonian approximation the Einstein
equations can be reduced to the standard Maxwell-type field equations in a
medium; in such a context the Cerenkov emission by a neutralparticle gives
large energy loss while the particle moves at faster than the phase speed of
waves in the medium.


title:
On the significance in signal search through the sliding window
  algorithm

abstract:
  The experimental issue of the search for new particles of unknown mass poses
the challenge of exploring a wide interval to look for the usual signatures
represented by excess of events above the background. A side effect of such a
broad range quest is that the traditional significance calculations valid for
signals of known location are no more applicable when such an information is
missing. In this note the specific signal search approach via observation
windows sliding over the range of interest is considered; in the assumptions of
known background and of fixed width of the exploring windows the statistical
implications of such a search scheme are described, with special emphasis on
the correct significance assessment for a claimed discovery.


title: Dynamics of the return distribution in the Korean financial market

abstract:
  In this paper, we studied the dynamics of the log-return distribution of the
Korean Composition Stock Price Index (KOSPI) from 1992 to 2004. Based on the
microscopic spin model, we found that while the index during the late 1990s
showed a power-law distribution, the distribution in the early 2000s was
exponential. This change in distribution shape was caused by the duration and
velocity, among other parameters, of the information that flowed into the
market.


title: Introduction to Quantum Cryptography

abstract:
  We show in details the four quantum key distribution protocols which
initiated the important field of quantum cryptography, using an accessible
language for undergraduate students. We begin presenting the BB84 protocol,
which uses polarization states of photons in order to transmit cryptographic
keys. Thereupon we show the E91 protocol, whose security is based on the use of
singlet states to generate a random sequence of bits. We end the paper with the
BBM92 and the B92 protocol. These last two protocols can be seen as simplified
versions of the first two.


title:
Identification of a Damage Law by Using Full-Field Displacement
  Measurements

abstract:
  It is proposed to identify damage variables and their growth with loading in
two dimensions by only using full-field displacement measurements. The
equilibrium gap method is used to estimate the damage field during a biaxial
experiment on a sample made of a composite material. From the analysis of a
sequence of measurements, a proposed form of constitutive law is tested and
identified. The emphasis is put on the methodology that can be applied to a
vast class of materials.


title:
Digital Image Correlation: From Displacement Measurement to
  Identification of Elastic Properties - A Review

abstract:
  The current development of digital image correlation, whose displacement
uncertainty is well below the pixel value, enables one to better characterise
the behaviour of materials and the response of structures to external loads. A
general presentation of the extraction of displacement fields from the
knowledge of pictures taken at different instants of an experiment is given.
Different strategies can be followed to achieve a sub-pixel uncertainty. From
these measurements, new identification procedures are devised making use of
full-field measures. A priori or a posteriori routes can be followed. They are
illustrated on the analysis of a Brazilian test.


title:
Pump-probe nonlinear magneto-optical rotation with frequency modulated
  light

abstract:
  Specific types of atomic coherences between Zeeman sublevels can be generated
and detected using a method based on nonlinear magneto-optical rotation with
frequency modulated light. Linearly polarized, frequency modulated light is
employed to selectively generate ground-state coherences between Zeeman
sublevels for which $\Delta m=2$ and $\Delta m=4$ in $^{85}$Rb and $^{87}$Rb
atoms, and additionally $\Delta m=6$ in $^{85}$Rb. The atomic coherences are
detected with a separate, unmodulated probe light beam. Separation of the pump
and probe beams enables independent investigation of the processes of creation
and detection of the atomic coherences. With the present technique the transfer
of the Zeeman coherences, including high-order coherences, from excited to
ground state by spontaneous emission has been observed.


title: Early nonlinear regime of MHD internal modes: the resistive case

abstract:
  It is shown that the critical layer analysis, involved in the linear theory
of internal modes, can be extended continuously into the early nonlinear
regime. For the m=1 resistive mode, the dynamical analysis involves two small
parameters: the inverse of the magnetic Reynolds number S and the m=1 mode
amplitude A, that measures the amount of nonlinearities in the system. The
location of the instantaneous critical layer and the dominant dynamical
equations inside it are evaluated self-consistently, as A increases and crosses
some S-dependent thresholds. A special emphasis is put on the influence of the
initial q-profile on the early nonlinear behavior. Predictions are given for a
family of q-profiles, including the important low shear case, and shown to be
consistent with recent experimental observations.


title:
A New Approach to Analyse $H\otimes (2h\oplus g)$ Jahn-Teller System for
  $C_{60}$

abstract:
  It is now well known that electron (hole)-vibron coupling and hence
Jahn-Teller (JT) effect is important understanding the properties of $C_{60}$
and related molecules. In this paper, we study $H\otimes (2h\oplus g)$ coupling
case to find the potential energy surfaces for the positively charged $C_{60}$
molecule due to distortion. The $H\otimes (2h\oplus g)$ Jahn-Teller system is
of particular importance as this will be the JT effect displayed by $C_{60}$
molecules removed with an electron. $C_{60}^{+}$ is obtained by removing one
electron from fivefold degenerate Hu highest occupied molecular orbital (HOMO)
and a hole in HOMO interacts with the vibrational modes of $C_{60}$ and
symmetry is broken. We apply the method of symmetry breaking mechanism to
obtain expressions for the potential energy surface.


title:
Nonlinear evolution of the m=1 internal kink mode in the presence of
  magnetohydrodynamic turbulence

abstract:
  The nonlinear evolution of the m=1 internal kink mode is studied numerically
in a setting where the tokamak core plasma is surrounded by a turbulent region
with low magnetic shear. As a starting point we choose configurations with
three nearby q=1 surfaces where triple tearing modes (TTMs) with high poloidal
mode numbers m are unstable. While the amplitudes are still small, the fast
growing high-m TTMs enhance the growth of the m=1 instability. This is
interpreted as a fast sawtooth trigger mechanism. The TTMs lead to a partial
collapse, leaving behind a turbulent belt with q ~= 1 around the unreconnected
core plasma. Although, full reconnection can occur if the core displacement
grows large enough, it is shown that the turbulence may actively prevent
further reconnection. This is qualitatively similar to experimentally observed
partial sawtooth crashes with post-cursor oscillations due to a saturated
internal kink.


title: A Note on Linear Force Model in Car Accident Reconstruction

abstract:
  In the paper the linear force model used in car accident simulation programs
is discussed. A model of restitution is proposed and the possible
interpretation of CRASH coefficients is also discussed.


title: Traffic Flow by Cellular Automata: the Effect of Maximal Car Velocity

abstract:
  Effects of large value assigned to the maximal car velocity on the
fundamental diagrams in the Nagel-Schreckenberg model are studied by extended
simulations. The function relating the flow in the congested traffic phase with
the car density and deceleration probability is found numerically. Properties
of the region of critical changes, so-called jamming transition parameters, are
described in details. The basic model, modified by the assumption that for each
car an individual velocity limit is assigned, is investigated in the aim to
find the best supplementary rule allowing the jammed traffic to move with
velocity larger than the slowest driving vehicle.


title: Description of dynamics of stock prices by a Langevin approach

abstract:
  We present a time-dependent Langevin description of dynamics of stock prices.
Based on a simple sliding-window algorithm, the fluctuation of stock prices is
discussed in the view of a time-dependent linear restoring force which is the
linear approximation of the drift parameter in Langevin equation estimated from
the financial time series. By choosing suitable weighted factor for the linear
approximation, the relation between the dynamical effect of restoring force and
the autocorrelation of the financial time series is deduced. We especially
analyze the daily log-returns of S$&$P 500 index from 1950 to 1999. The
significance of the restoring force towards the prices evolution are
investigated from its two coefficients, slope coefficient and equilibrium
position. The new simple form of the restoring force obtained both from
statistical and theoretical analyses suggests that the Langevin approach can
effectively present the macroscopical and the detail properties of the price
evolution.


title:
Between light and eye: Goethe's science of color and the polar
  phenomenology of nature

abstract:
  In his interviews with Eckermann in the 1820s, Goethe referred to his Theory
of Colors as his greatest and ultimate achievement. Its reception following
publication in 1810 and subsequent reviews throughout the history of physical
science did not reflect this self-assessment. Even Hermann von Helmholtz, who
in part modeled his scientific work after Goethe's, initially thought that
Goethe's poetic genius prevented him from understanding physical science. Why
did Goethe champion his Farbenlehre so ardently even years after it was
dismissed by almost everyone else? In answering this question, this essay will
attempt to add to the existing scholarship by considering Goethe's Theory of
Colors in the context of his natural philosophy, and generalizing the variety
of objectifications of the concepts invoked by his color theory and their
relationships to Goethe's epistemology and Newton's mechanics. In this fashion,
I attempt to show that the reason for Goethe's self-assessment of his Theory of
Colors is less enigmatic than appears from its examination solely as a work of
physics. Rather, Zur Farbenlehre was the clearest expression of Goethe's most
universal archetype-- polarity of opposites-- which bridged Goethe's conflicts
with Kant's and Spinoza's epistemologies, and in an over-reaching way served as
a cosmology underlying Goethe's art and his science.


title:
Fitting potential energy surface of reactive system via genetic
  algorithm

abstract:
  In this work, we present a new fitting of the Na+HF potential energy surface
(PES) utilizing a new optmization method based in Genetic Algorithm. Topology
studies, such as isoenergetic contours and Minimum Energy Path(MEP), show that
the quality of this new PES is comparable to the best PES of literature. These
facts, suggests that this new approach can be utilized as new tool to fit PES
of reactive systems.


title: A genetic algorithm to build diatomic potentials

abstract:
  Several types of numerical and combinatorial optimization algorithms have
been used as useful tools to minimize functional forms. Generally, when those
forms are non-linear or occur in problems without a specific optimization
method, stochastic methods based on search algorithms have shown good results
due to its smaller susceptibility to be trapped in a local minimum. Besides
that, they can be easily implemented to work with other techniques In this
algorithms class, the genetic ones have received special attention because they
are a robust optimization tool. An algorithm can be named genetic when it uses
some kind of codification to transform a set of possible solutions of a given
problem in a population that will evolve subject to operators inspired, or not,
by mechanisms of natural selection. In other words, they work with a population
of solutions to obtain better solutions in the next generation. To do this,
they use only information of cost and prize. In this work, we propose a genetic
algorithm optimization technique (GAOT) to fit diatomic potential energy
curves.In order to show this method, we obtain the analytical functions of the
H2+ and Li2 systems using the ab initio energy calculations as well as Rydberg
trial function. These studies show that the quality of the GAOT fitting is
comparable to the best optimization techniques recommended to fit diatomic
systems. The introduction of this new technique is important because it arises
as a new option to fit PES for reactive scattering dynamics.


title:
Strongly nonexponential time-resolved fluorescence of quantum-dot
  ensembles in three-dimensional photonic crystals

abstract:
  We observe experimentally that ensembles of quantum dots in three-dimensional
(3D) photonic crystals reveal strongly nonexponential time-resolved emission.
These complex emission decay curves are analyzed with a continuous distribution
of decay rates. The log-normal distribution describes the decays well for all
studied lattice parameters. The distribution width is identified with
variations of the radiative emission rates of quantum dots with various
positions and dipole orientations in the unit cell. We find a striking sixfold
change of the width of the distribution by varying the lattice parameter. This
interpretation qualitatively agrees with the calculations of the 3D projected
local density of states. We therefore conclude that fluorescence decay of
ensembles of quantum dots is highly nonexponential to an extent that is
controlled by photonic crystals.


title: A numerical simulation of the backward Raman amplifying in plasma

abstract:
  This paper describe a numerical simulation method for the interaction between
laser pulses and low density plasmas based on hydrodynamic approximation. We
investigate Backward Raman Amplifying (BRA) experiments and their variants. The
numerical results are in good agreement with experiments.


title: The Real Message in the Sky

abstract:
  A recent paper by Hsu & Zee (physics/0510102) suggests that if a Creator
wanted to leave a message for us, and she wanted it to be decipherable to all
sentient beings, then she would place it on the most cosmic of all billboards,
the Cosmic Microwave Background (CMB) sky. Here we point out that the spherical
harmonic coefficients of the observed CMB anisotropies (or their squared
amplitudes at each multipole) depend on the location of the observer, in both
space and time. The amount of observer-independent information available in the
CMB is a small fraction of the total that any observer can measure. Hence a
lengthy message on the CMB sky is fundamentally no less observer-specific than
a communication hidden in this morning's tea-leaves. Nevertheless, the CMB sky
does encode a wealth of information about the structure of the cosmos and
possibly about the nature of physics at the highest energy levels. The Universe
has left us a message all on its own.


title: States of Traffic Flow in Deep Lefortovo Tunnel (Moscow): Empirical Data

abstract:
  The paper presents a preliminary analysis of traffic flow data collected in
the Lefortovo tunnel located on the 3-rd circular highway of Moscow.
  It is shown that the observed tunnel congested traffic in fact exhibits
cooperative phenomena in vehicle motion, namely, there is a region of widely
scatted states on the fundamental diagrams which is related typically to the
appearance of synchronized traffic. Besides, the spatial autocorrelations in
the occupancy, vehicle velocity, and flow rate measured by different detectors
are found to be essential. Especially it concerns the correlations in the
velocity and occupancy, their correlation length gets values about 1 km.
  The phase portrait of the vehicle ensemble dynamics on the occupancy-velocity
plane is also studied. It is demonstrated that there are two substantially
different region on it. One matches actually the cooperative vehicle motion and
contains some kernel where the dynamics is pure chaotic. The other part of the
phase plane corresponds to the irreversible stage of jam formation.


title: Complex networks in brain electrical activity

abstract:
  We analyze the complex networks associated with brain electrical activity.
Multichannel EEG measurements are first processed to obtain 3D voxel
activations using the tomographic algorithm LORETA. Then, the correlation of
the current intensity activation between voxel pairs is computed to produce a
voxel cross-correlation coefficient matrix. Using several correlation
thresholds, the cross-correlation matrix is then transformed into a network
connectivity matrix and analyzed. To study a specific example, we selected data
from an earlier experiment focusing on the MMN brain wave. The resulting
analysis highlights significant differences between the spatial activations
associated with Standard and Deviant tones, with interesting physiological
implications. When compared to random data networks, physiological networks are
more connected, with longer links and shorter path lengths. Furthermore, as
compared to the Deviant case, Standard data networks are more connected, with
longer links and shorter path lengths--i.e., with a stronger ``small worlds''
character. The comparison between both networks shows that areas known to be
activated in the MMN wave are connected. In particular, the analysis supports
the idea that supra-temporal and inferior frontal data work together in the
processing of the differences between sounds by highlighting an increased
connectivity in the response to a novel sound.


title: Dynamics with Low-Level Fractionality

abstract:
  The notion of fractional dynamics is related to equations of motion with one
or a few terms with derivatives of a fractional order. This type of equation
appears in the description of chaotic dynamics, wave propagation in fractal
media, and field theory. For the fractional linear oscillator the physical
meaning of the derivative of order $\alpha<2$ is dissipation. In systems with
many spacially coupled elements (oscillators) the fractional derivative, along
the space coordinate, corresponds to a long range interaction. We discuss a
method of constructing a solution using an expansion in $\epsilon=n-\alpha$
with small $\epsilon$ and positive integer $n$. The method is applied to the
fractional linear and nonlinear oscillators and to fractional Ginzburg-Landau
or parabolic equations.

categories: physics.class-ph cond-mat.other math-ph math.DS math.MP nlin.CD physics.gen-ph


title: Resolution of sub-wavelength lenses formed by the wire medium

abstract:
  The restrictions on the resolution of transmission devices formed by wire
media (arrays of conductive cylinders) recently proposed in [Phys. Rev. B, 71,
193105 (2005)] and experimentally tested in [Phys. Rev. B, 73, 033108 (2006)]
are studied in this paper using both analytical and numerical modeling. It is
demonstrated that such transmission devices have sub-wavelength resolution that
can in principle be made as fine as required by a specific application by
controlling the lattice constant of the wire medium. This confirms that slabs
of the wire medium are unique imaging devices at the microwave frequency range,
and are capable of transmitting distributions of TM-polarized electric fields
with nearly unlimited sub-wavelength resolution to practically arbitrary
distances.


title: Statistical considerations on safety analysis

abstract:
  Alerting experience with a well-acknowledged safety analysis code initiated
the authors to pay attention to safety issues of complex systems. Their first
concern was the statistical characteristics of such a code. We point out a
remarkable weakness of the so called 0.95/0.95 methodology: when repeating the
search for the tolerance limit, we get a higher value with non-negligible
probability. We propose the sign test as an alternative method. We point out
the correct form of Wilks' formula when the number of parameters subjected to
limitation is two or more.


title:
Intelligent Controlling Simulation of Traffic Flow in a Small City
  Network

abstract:
  We propose a two dimensional probabilistic cellular automata for the
description of traffic flow in a small city network composed of two
intersections. The traffic in the network is controlled by a set of traffic
lights which can be operated both in fixed-time and a traffic responsive
manner. Vehicular dynamics is simulated and the total delay experienced by the
traffic is evaluated within specified time intervals. We investigate both
decentralized and centralized traffic responsive schemes and in particular
discuss the implementation of the {\it green-wave} strategy. Our investigations
prove that the network delay strongly depends on the signalisation strategy. We
show that in some traffic conditions, the application of the green-wave scheme
may destructively lead to the increment of the global delay.


title: Withdrawal

abstract: This paper has been withdrawn


title:
Influence of Electron Diffusion On The Wave Front Shape for Intense
  Shock Waves in Xenon

abstract:
  A bifurcation of strong shock waves front for xenon in a shock tube has been
noted. We propose a model which explains the effect and gives a variation-law
of the front shape with respect to the Mach number M and the unperturbed gas
pressure p1.


title: Fractional Ginzburg-Landau equation for fractal media

abstract:
  We derive the fractional generalization of the Ginzburg-Landau equation from
the variational Euler-Lagrange equation for fractal media. To describe fractal
media we use the fractional integrals considered as approximations of integrals
on fractals. Some simple solutions of the Ginzburg-Landau equation for fractal
media are considered and different forms of the fractional Ginzburg-Landau
equation or nonlinear Schrodinger equation with fractional derivatives are
presented. The Agrawal variational principle and its generalization have been
applied.

categories: physics.class-ph cond-mat.mtrl-sci cond-mat.other cond-mat.stat-mech math-ph math.MP nlin.CD


title: Data Compression with Prime Numbers

abstract:
  A compression algorithm is presented that uses the set of prime numbers.
Sequences of numbers are correlated with the prime numbers, and labeled with
the integers. The algorithm can be iterated on data sets, generating factors of
doubles on the compression.


title:
Path-integral virial estimator for reaction rate calculation based on
  the quantum instanton approximation

abstract:
  The quantum instanton approximation is a type of quantum transition state
theory that calculates the chemical reaction rate using the reactive flux
correlation function and its low order derivatives at time zero. Here we
present several path-integral estimators for the latter quantities, which
characterize the initial decay profile of the flux correlation function. As
with the internal energy or heat capacity calculation, different estimators
yield different variances (and therefore different convergence properties) in a
Monte Carlo calculation. Here we obtain a virial-type estimator by using a
coordinate scaling procedure rather than integration by parts, which allows
more computational benefits. We also consider two different methods for
treating the flux operator, i.e., local-path and global-path approaches, in
which the latter achieves a smaller variance at the cost of using second-order
potential derivatives. Numerical tests are performed for a one-dimensional
Eckart barrier and a model proton transfer reaction in a polar solvent, which
illustrates the reduced variance of the virial estimator over the corresponding
thermodynamic estimator.


title:
Controlling Silver Nanoparticle Size and Morphology with Photostimulated
  Synthesis

abstract:
  Photo-induced synthesis and control over the size and shape of colloidal
silver nanoparticles is investigated in contrast to photo-stimulated
aggregation of small nanoparticles into large fractal-type structures. The
feasibility of light-driven nanoengineering which enables manipulation of the
sizes and shapes of the isolated nanoparticles is studied by varying the amount
and type of the stabilizing agent and the type of optical irradiation.


title:
Digital Image Correlation used to Analyze the Multiaxial Behavior of
  Rubber-like Materials

abstract:
  We present an experimental approach to discriminate models describing the
mechanical behavior of polymeric materials. A biaxial loading condition is
obtained in a multiaxial testing machine. An evaluation of the displacement
field obtained by digital image correlation allows us to evaluate the
heterogeneous strain field observed during these tests. We focus on the
particular case of hyper-elastic models to simulate the behavior of a
rubber-like material. Different expressions of hyper-elastic potential are used
to model experiments under uniaxial and biaxial loading conditions.


title:
Ambivalent effects of added layers on steady kinematic dynamos in
  cylindrical geometry: application to the VKS experiment

abstract:
  The intention of the ''von Karman sodium'' (VKS) experiment is to study the
hydromagnetic dynamo effect in a highly turbulent and unconstrained flow. Much
effort has been devoted to the optimization of the mean flow and the lateral
boundary conditions in order to minimize the critical magnetic Reynolds number
and hence the necessary motor power. The main focus of this paper lies on the
role of ''lid layers'', i.e. layers of liquid sodium between the impellers and
the end walls of the cylinder. First, we study an analytical test flow to show
that lid layers can have an ambivalent effect on the efficiency of the dynamo.
The critical magnetic Reynolds number shows a flat minimum for a small lid
layer thickness, but increases for thicker layers. For the actual VKS geometry
it is shown that static lid layers yield a moderate increase of the critical
magnetic Reynolds number by approximately 12 per cent. A more dramatic increase
by 100 until 150 per cent can occur when some rotational flow is taken into
account in those layers. Possible solutions of this problem are discussed for
the real dynamo facility.


title:
Cu-TBPP and PTCDA molecules on insulating surfaces studied by
  ultra-high-vacuum non-contact AFM

abstract:
  The adsorption of two kinds of porphyrin (Cu-TBPP) and perylene (PTCDA)
derived organic molecules deposited on KBr and Al2O3 surfaces has been studied
by non-contact force microscopy in ultra-high vacuum, our goal being the
assembly of ordered molecular arrangements on insulating surfaces at room
temperature. On a Cu(100) surface, well ordered islands of Cu-TBPP molecules
were successfully imaged. On KBr and Al2O3 surfaces, it was found that the same
molecules aggregate in small clusters at step edges, rather than forming
ordered monolayers. First measurements with PTCDA on KBr show that
nanometre-scale rectangular pits in the surface can act as traps to confine
small molecular assemblies.


title:
Distance dependence of force and dissipation in non-contact atomic force
  microscopy on Cu(100) and Al(111)

abstract:
  The dynamic characteristics of a tip oscillating in the nc-AFM mode in close
vicinity to a Cu(100)-surface are investigated by means of phase variation
experiments in the constant amplitude mode. The change of the quality factor
upon approaching the surface deduced from both frequency shift and excitation
versus phase curves yield to consistent values. The optimum phase is found to
be independent of distance. The dependence of the quality factor on distance is
related to 'true' damping, because artefacts related to phase misadjustment can
be excluded. The experimental results, as well as on-resonance measurements at
different bias voltages on an Al(111) surface, are compared to Joule
dissipation and to a model of dissipation in which long-range forces lead to
viscoelastic deformations.


title: Role of fluctuations in a snug-fit mechanism of KcsA channel selectivity

abstract:
  The KcsA potassium channel belongs to a class of K+ channels that is
selective for K+ over Na+ at rates of K+ transport approaching the diffusion
limit. This selectivity is explained thermodynamically in terms of favorable
partitioning of K+ relative to Na+ in a narrow selectivity filter in the
channel. One mechanism for selectivity based on the atomic structure of the
KcsA channel invokes the size difference between K+ and Na+, and the molecular
complementarity of the selectivity filter with the larger K+ ion. An
alternative view holds that size-based selectivity is precluded because atomic
structural fluctuations are greater than the size difference between these two
ions. We examine these hypotheses by calculating the distribution of binding
energies for Na+ and K+ in a simplified model of the selectivity filter of the
KcsA channel. We find that Na+ binds strongly to the selectivity filter with a
mean binding energy substantially lower than that for K+. The difference is
comparable to the difference in hydration free energies of Na+ and K+ in bulk
aqueous solution. Thus, the average filter binding energies do not discriminate
Na+ from K+ when measured from the baseline of the difference in bulk hydration
free energies. Instead, Na+/K+ discrimination can be attributed to scarcity of
good binding configurations for Na+ compared to K+. That relative scarcity is
quantified as enhanced binding energy fluctuations, and is consistent with
predicted relative constriction of the filter by Na+.


title:
Cavity Q, mode volume, and lasing threshold in small diameter AlGaAs
  microdisks with embedded quantum dots

abstract:
  The quality factor (Q), mode volume (Veff), and room-temperature lasing
threshold of microdisk cavities with embedded quantum dots (QDs) are
investigated. Finite element method simulations of standing wave modes within
the microdisk reveal that Veff can be as small as 2(lambda/n)^3 while
maintaining radiation-limited Qs in excess of 10^5. Microdisks of diameter D=2
microns are fabricated in an AlGaAs material containing a single layer of InAs
QDs with peak emission at lambda = 1317 nm. For devices with Veff ~2
(lambda/n)^3, Qs as high as 1.2 x 10^5 are measured passively in the 1.4 micron
band, using an optical fiber taper waveguide. Optical pumping yields laser
emission in the 1.3 micron band, with room temperature, continuous-wave
thresholds as low as 1 microWatt of absorbed pump power. Out-coupling of the
laser emission is also shown to be significantly enhanced through the use of
optical fiber tapers, with laser differential efficiency as high as xi~16% and
out-coupling efficiency in excess of 28%.


title:
Temperature Effects on Threshold Counterion Concentration to Induce
  Aggregation of fd Virus

abstract:
  We seek to determine the mechanism of like-charge attraction by measuring the
temperature dependence of critical divalent counterion concentration
($\rm{C_{c}}$) for the aggregation of fd viruses. We find that an increase in
temperature causes $\rm{C_c}$ to decrease, primarily due to a decrease in the
dielectric constant ($\epsilon$) of the solvent. At a constant $\epsilon$,
$\rm{C_c}$ is found to increase as the temperature increases. The effects of
$T$ and $\epsilon$ on $\rm {C_{c}}$ can be combined to that of one parameter:
Bjerrum length ($l_{B}$). $\rm{C_{c}}$ decreases exponentially as $l_{B}$
increases, suggesting that entropic effect of counterions plays an important
role at the onset of bundle formation.


title:
A Simple Three-Parameter Model Potential For Diatomic Systems: From
  Weakly and Strongly Bound Molecules to Metastable Molecular Ions

abstract:
  Based on a simplest molecular orbital theory of H$_{2}^{+}$, a
three-parameter model potential function is proposed to describe ground-state
diatomic systems with closed-shell and/or S-type valence-shell constituents
over a significantly wide range of internuclear distances. More than 200 weakly
and strongly bound diatomics have been studied, including neutral and
singly-charged diatomics (e.g., H$_{2}$, Li$_{2}$, LiH, Cd$_{2}$, Na$_{2}^{+}$,
and RbH$^{-}$), long-range bound diatomics (e.g., NaAr, CdNe, He$_{2}$, CaHe,
SrHe, and BaHe), metastable molecular dications (e.g., BeH$^{++}$, AlH$^{++}$,
Mg$_{2}^{++}$, and LiBa$^{++}$), and molecular trications (e.g., YHe$^{+++}$
and ScHe$^{+++}$).


title:
Using probability and rules of interaction to simulate the spin
  relaxation in a MRI

abstract:
  A computer code is written that simulates the relaxation back to thermal
equilibrium of an ensemble of particles after a pi/2 pulse. Beginning with
Bloch's equations the exponential relaxation behavior is discussed and the
transition into a step by step process (from the continuous process) is made
such that it is possible for the computer code to simulate the action. An
analysis of Boltzmann's factor is offered and serves as the link between the
temperature of the ensemble and the parameter that is used to determine if a
spin is in the up state or the down state. The specifics of the code are
discussed and the spins are shown to follow the rules of interaction governed
by the physical collisions that can take place. Lastly, graphs of the
simulation are provided and a discussion of its usefulness is given.


title: Why we live in the Computational Universe

abstract:
  To better understand the deep significance of our best physical theories it
could be interesting to compare our Universe with its models. It may happen
that the differences between the model and reality can be made
indistinguishable, to the point that it may seem acceptable to consider reality
as a gigantic program, a 'mother computation' running in a Universal Computer.
The computational interpretation of reality is here adopted for introducing
concepts that are common in computer science, they may offer a new insight. For
instance, code and memory usage optimization techniques are common in computer
science because they improve the performances at a reduced hardware cost.
According to the concepts discussed in this paper, the possibility of
recognizing the effects of optimization rules in a physical reality will allow
us to discriminate if our reality is fundamental or the result of a large
computation. Conversely, code and memory optimization has side effects, if it
is present in our Universe it can produce many interesting phenomena, some seem
readily recognizable, others only wait to be discovered.


title:
Heavy Superheated Droplet Detectors as a Probe of Spin-independent WIMP
  Dark Matter Existence

abstract:
  At present, application of Superheated Droplet Detectors (SDDs) in WIMP dark
matter searches has been limited to the spin-dependent sector, owing to the
general use of fluorinated refrigerants which have high spin sensitivity. Given
their recent demonstration of a significant constraint capability with
relatively small exposures and the relative economy of the technique, we
consider the potential impact of heavy versions of such devices on the
spin-independent sector. Limits obtainable from a $\mathrm{CF_{3}I}$-loaded SDD
are estimated on the basis of the radiopurity levels and backgrounds already
achieved by the SIMPLE and PICASSO experiments. With 34 kgd exposure,
equivalent to the current CDMS, such a device may already probe to below
10$^{-6}$ pb in the spin-independent cross section.


title: New Interpretation for Laser Light Scattering Technique

abstract:
  The new method proposed in this work not only measures the particle size
distribution and the average molar mass accurately using the static light
scattering (SLS) technique when the Rayleigh-Gans-Debye approximation is valid
for dilute poly-disperse homogenous spherical particles in dispersion, but also
enables us to have insight into the theoretical analysis of the dimensionless
shape parameter $\rho$. With the method, a new size, static radii $R_{s}$, can
be measured. Based on the new static particle size information, detailed
investigation of the normalized time auto-correlation function of the scattered
light intensity $g^{(2)}(\tau)$ reveals that there exist three different
particle sizes: the static radius, hydrodynamic radius and apparent
hydrodynamic radius that is the hydrodynamic radius obtained using the
cumulants method. With a simple assumption that the hydrodynamic radius $R_{h}$
is in proportion to the static radius $R_{s}$, the expected values of
$g^{(2)}(\tau) $ calculated based on the static and commercial particle size
information are consistent with the experimental data. With the assistance of
simulated data, the apparent hydrodynamic radius is discussed. The results show
that the apparent hydrodynamic radius is different from the mean hydrodynamic
radius and is determined by the optical, hydrodynamic characteristics and size
distribution of particles and scattering vector. The analysis also reveals that
$\rho$ is determined by not only the structure of particles but also the
relationship between the optical and hydrodynamic characteristics of particles
even for mono-disperse model.


title:
Investigation of Volume Phase Transition from the Different Properties
  of Particles

abstract:
  In this work, three different particle sizes: the static radius $R_{s}$,
hydrodynamic radius $R_{h}$ and apparent hydrodynamic radius $ R_{h,app}$
obtained using the light scattering technique, are investigated for dilute
poly-disperse homogenous spherical particles with a simple assumption that the
hydrodynamic radius is in proportion to the static radius, when the
Rayleigh-Gans-Debye approximation is valid. The results show that the expected
values of the normalized time auto-correlation function of the scattered light
intensity $g^{(2)}(\tau) $ calculated based on the static particle size
information are consistent with the experimental data. The volume phase
transition is thus investigated using the equilibrium swelling ratios of static
radii and apparent hydrodynamic radii respectively. The changes of the static
particle size information and apparent hydrodynamic radius as a function of
temperature $T$ show the effects of the volume phase transition on optical
properties and the total influences of the volume phase transition on the
optical, hydrodynamic characteristics and size distribution of particles,
respectively. The effects of cross-linker on the volume phase transition are
also discussed.


title: Auto-correlation Function Study of Scattered Light Intensity

abstract:
  In this work, the particle size distribution measured using the dynamic light
scattering (DLS) technique is compared with that obtained from the static light
scattering (SLS) technique or provided by the supplier measured using the
Transmission Electron Microscopy (TEM) technique for dilute
Poly($N$-isopropylacrylamide) microgel and standard polystyrene latex samples
in dispersion respectively. The results show that the narrow particle size
distribution that can be measured accurately using the SLS technique is not
suited to the determination by the DLS technique and the particle size
distribution obtained from the DLS technique is different from the value
provided by the supplier. With the assistance of the simulated data of the
normalized time auto-correlation function of the scattered light intensity
$g^{(2)}(\tau)$, the effects of the particle size distribution on the
nonexponentiality of $g^{(2)}(\tau)$ measured at a scattering angle of
30$^\mathrm o$ are investigated. The analysis reveals that the influences of
the particle size distribution are small on the nonexponentiality of
$g^{(2)}(\tau)$ and very large on the initial slope of the logarithm of
$g^{(2)}(\tau)$. The values of the apparent hydrodynamic radius are also
largely influenced by the particle size distribution and the difference between
the distributions of the apparent hydrodynamic radius and hydrodynamic radius
of particles is determined by the method of cumulants.


title:
Compact solid-state laser source for 1S-2S spectroscopy in atomic
  hydrogen

abstract:
  We demonstrate a novel compact solid-state laser source for high-resolution
two-photon spectroscopy of the $1S-2S$ transition in atomic hydrogen. The
source emits up to 20 mW at 243 nm and consists of a 972 nm diode laser, a
tapered amplifier, and two doubling stages. The diode laser is actively
stabilized to a high-finesse cavity. We compare the new source to the stable
486 nm dye laser used in previous experiments and record 1S-2S spectra using
both systems. With the solid-state laser system we demonstrate a resolution of
the hydrogen spectrometer of 6 \times 10^{11} which is promising for a number
of high-precision measurements in hydrogen-like systems.


title: Infinite non-causality in active cancellation of random noise

abstract:
  Active cancellation of broadband random noise requires the detection of the
incoming noise with some time advance. In an duct for example this advance must
be larger than the delays in the secondary path from the control source to the
error sensor. In this paper it is shown that, in some cases, the advance
required for perfect noise cancellation is theoretically infinite because the
inverse of the secondary path, which is required for control, can include an
infinite non-causal response. This is shown to be the result of two mechanisms:
in the single-channel case (one control source and one error sensor), this can
arise because of strong echoes in the control path. In the multi-channel case
this can arise even in free field simply because of an unfortunate placing of
sensors and actuators. In the present paper optimal feedforward control is
derived through analytical and numerical computations, in the time and
frequency domains. It is shown that, in practice, the advance required for
significant noise attenuation can be much larger than the secondary path
delays. Practical rules are also suggested in order to prevent infinite
non-causality from appearing.


title:
Active control of scattered acoustic radiation: a real-time
  implementation

abstract:
  This paper presents an active noise control experiment designed to validate a
real-time control strategy for reduction of the noise scattered from a
three-dimensional body. The control algorithm relies on estimating the
scattered noise by linear filtering of the total noise measured around the
body; suitable filters are identified from off-line measurements. A modified
Filtered-Error Least-Mean-Squares algorithm then leads to the adaptive filters
which drive the secondary sources. The paper provides the numerical simulations
using a Boundary Element Method which helped in designing a feasible experiment
in an anechoic chamber with a limited number of control sources. Eventually a
real-time pure-tone implementation with 14 ordinary loudspeakers and a large
body is shown to yield on average a 10 dB reduction of the scattered noise at
the error sensors, which is close to the optimum reduction predicted by the
numerical simulations for the sensor arrangement.


title:
Beam Performance and Luminosity Limitations in the High-Energy Storage
  Ring (HESR)

abstract:
  The High-Energy Storage Ring (HESR) of the future International Facility for
Antiproton and Ion Research (FAIR) at GSI in Darmstadt is planned as an
antiproton synchrotron and storage ring in the momentum range from 1.5 to 15
GeV/c. An important feature of this new facility is the combination of phase
space cooled beams with dense internal targets (e.g. pellet targets), resulting
in demanding beam parameter of two operation modes: high luminosity mode with
peak luminosities up to 2*10^32 cm-2 s-1, and high resolution mode with a
momentum spread down to 10^-5, respectively. To reach these beam parameters
very powerful phase space cooling is needed, utilizing high-energy electron
cooling and high-bandwidth stochastic cooling. The effect of beam-target
scattering and intra-beam interaction is investigated in order to study beam
equilibria and beam losses for the two different operation modes.


title: Design and Performance of the CMS Pixel Detector Readout Chip

abstract:
  The readout chip for the CMS pixel detector has to deal with an enormous data
rate. On-chip zero suppression is inevitable and hit data must be buffered
locally during the latency of the first level trigger. Dead-time must be kept
at a minimum. It is dominated by contributions coming from the readout. To keep
it low an analog readout scheme has been adopted where pixel addresses are
analog coded. We present the architecture of the final CMS pixel detector
readout chip with special emphasis on the analog readout chain. Measurements of
its performance are discussed.


title: Wasa at Cosy

abstract:
  The Wide Angle Shower Apparatus (WASA) has been transferred from the storage
ring CELSIUS (TSL, Uppsala, Sweden) to the cooler synchrotron COSY (FZ Juelich,
Germany). In this presentation, the status and planning of the WASAatCOSY
project are reported. The main physics aspects are rare decays of eta and eta'
mesons and isospin violation in deuteron-deuteron interactions.


title: Laser frequency stabilization to a single ion

abstract:
  A fundamental limit to the stability of a single-ion optical frequency
standard is set by quantum noise in the measurement of the internal state of
the ion. We discuss how the interrogation sequence and the processing of the
atomic resonance signal can be optimized in order to obtain the highest
possible stability under realistic experimental conditions. A servo algorithm
is presented that stabilizes a laser frequency to the single-ion signal and
that eliminates errors due to laser frequency drift. Numerical simulations of
the servo characteristics are compared to experimental data from a frequency
comparison of two single-ion standards based on a transition at 688 THz in
171Yb+. Experimentally, an instability sigma_y(100 s)=9*10^{-16} is obtained in
the frequency difference between both standards.


title:
Serial and parallel combinations of diodes: equivalence formulae and
  their do-main of validity

abstract:
  Serial and parallel combinations of diodes are studied by first establishing
approached equivalence formulae. Sorting diodes enlights the true dispersion of
their characteristics. This simple exercice helps students to realize that
"identical" components may have in fact slightly different behaviour,
especially in analogic electronic. Using very common components like diodes and
simple electronics assembly, students can then face and test the notion of
practical domain of validity for a theoretically established formula. Using
diodes is especially interesting to introduce these notions, because the domain
of application of the proposed formulae strongly depends on the components
combination (parallel or serial), because of their non-linear behaviour.


title: Evolution of Continuum from Elastic Deformation to Flow

abstract:
  Traditionally, the deformation of continuum is divided into elastic, plastic,
and flow. For a large deformation with cracking, they are combined together.
So, for complicated deformation, a formulation to express the evolution of
deformation from elastic to flow will help to understand the intrinsic relation
among the related parameters which relate the deformation with a stress field.
To this purpose, Eringen polar decomposition and Trusedell polar decomposition
are formulated by explicit formulation of displacement field, based on Chen
additive decomposition of deformation gradient. Then the strain introduced by
the multiplicative decomposition and the strain introduced by the additive
decomposition are formulated explicitly with displacement gradient. This
formulation clears the intrinsic contents of strains defined by taking the
Eringen polar decomposition and Trusedell polar decomposition. After that, it
shows that the plastic deformation can be expressed as the irreversible local
average rotation. For initial isotropic simple elastic material, the
path-dependent feature of classical plasticity theory is naturally expressed in
Chen strain definition. It is founded that for initially isotropic material the
motion equations require a non-symmetric stress for dynamic deformation and a
symmetric stress for static deformation. This controversy between dynamic
deformation and static deformation can be used to explain the cracking or
buckling of solid continuum. Finally, the research shows that the flow motion
of continuum can be expressed by the same formulation system. So, it forms an
evolution theory from elastic deformation to flow of continuum.


title: Redundancy of stereoscopic images: Experimental Evaluation

abstract:
  With the recent advancement in visualization devices over the last years, we
are seeing a growing market for stereoscopic content. In order to convey 3D
content by means of stereoscopic displays, one needs to transmit and display at
least 2 points of view of the video content. This has profound implications on
the resources required to transmit the content, as well as demands on the
complexity of the visualization system. It is known that stereoscopic images
are redundant, which may prove useful for compression and may have positive
effect on the construction of the visualization device. In this paper we
describe an experimental evaluation of data redundancy in color stereoscopic
images. In the experiments with computer generated and real life and test
stereo images, several observers visually tested the stereopsis threshold and
accuracy of parallax measuring in anaglyphs and stereograms as functions of the
blur degree of one of two stereo images and color saturation threshold in one
of two stereo images for which full color 3D perception with no visible color
degradations is maintained. The experiments support a theoretical estimate that
one has to add, to data required to reproduce one of two stereoscopic images,
only several percents of that amount of data in order to achieve stereoscopic
perception.


title: Instantaneous Interaction between Charged Particles

abstract:
  The interaction between charged particles through quasi-static fields must
occur instantaneously; otherwise a violation of the energy principle would
occur. As a consequence, the instantaneous transmission of both energy and
information over macroscopic distances is feasible by using the quasi-static
fields which are predicted by Maxwell's equations.


title: D0 Silicon Microstrip Tracker

abstract:
  The D0 Run II silicon microstrip tracker (SMT) has 3 square meters of Si
area. There are 792,576 channels read out by 6192 SVXIIe chips on 912 read out
modules. The SMT provides track and vertex reconstruction capabilities over the
full pseudorapidity coverage of the D0 detector. The full detector has been
running successfully since April 2002. This presentation covers the experience
in commissioning and operating, the recent electronics upgrade which improved
stability of the SMT and estimates of the radiation damage.


title: Delay of Disorder by Diluted Polymers

abstract:
  We study the effect of diluted flexible polymers on a disordered capillary
wave state. The waves are generated at an interface of a dyed water sugar
solution and a low viscous silicon oil. This allows for a quantitative
measurement of the spatio-temporal Fourier spectrum. The primary pattern after
the first bifurcation from the flat interface are squares. With increasing
driving strength we observe a melting of the square pattern. It is replaced by
a weak turbulent cascade. The addition of a small amount of polymers to the
water layer does not affect the critical acceleration but shifts the disorder
transition to higher driving strenghs and the short wave length - high
frequency fluctuations are suppressed.


title:
A viscous compressible model of soap film flow and its equivalence with
  the Navier-Stokes equations

abstract:
  We present a quasi-two dimensional model of flowing soap films that bears
striking similarity to the compressible Navier-Stokes equations. The variation
in soap film thickness that is commonly used for flow visualization in
experiments is analogous to density variations in the Navier-Stokes equations.
When the soap film flow velocity is comparable to the Marangoni elastic wave
velocity we recover the compressible Navier-Stokes equations and the soap film
behaves like a two-dimensional isothermal viscous gas.


title: Entropy, geometry, and the quantum potential

abstract:
  We sketch and emphasize the automatic emergence of a quantum potential Q in
e.g. classical WDW type equations upon inserting a (Bohmian) complex wave
function. The interpretation of Q in terms of momentum fluctuations via Fisher
information and entropy ideas is discussed along with the essentially forced
role of the amplitude squared as a probability density. We also review the
constructions of Padmanabhan connecting entropy and the Einstein equations.


title:
Optimized Integration of the Equations of Motion of a Particle in the
  HERA-B Magnet

abstract:
  In this note we present a flexible approach to perform the propagation of
track parameters and their derivatives in an inhomogeneous magnetic field,
keeping the computational effort small. We discuss also a Kalman filter
implementation using this optimized computation of the derivatives.


title:
Do redshifted cosmological photons really violate the principle of
  energy conservation?

abstract:
  Although the Universe is far from understood, we are fairly confident about
some key features: Special Relativity (SR) describes the kinematics of inertial
frames; General Relativity (GR) explains gravitation; the Universe had a
beginning in time and has been expanding since. Nevertheless it is quite
difficult to see the 'big picture', although the idea of applying GR to the
entire Universe has been very successful with a model emerging that is
consistent with observation. One unpleasant feature of the model is that
cosmological photons appear not to conserve energy, and the only explanation
forthcoming is the claim that GR is exempt from the principle of energy
conservation. It is demonstrated here that cosmological observations may
legitimately be projected onto flat spacetime and can then be treated Special
Relativistically, whereupon energy conservation is restored. This is not to say
that the concordance General Relativistic cosmological model is incorrect, just
that in observational terms there is no energy conservation anomaly.


title: Stiff three-frequency orbit of the hydrogen atom

abstract:
  We study a stiff quasi-periodic orbit of the electromagnetic two-body problem
of Dirac's electrodynamics of point charges. We expand the delay equations of
motion about circular orbits to obtain the variational equations up to
nonlinear terms. We study the normal modes of the variational dynamics with
period of the order of the time for light to travel the interparticle distance.
In the atomic magnitude these are fast frequencies compared to the circular
rotation. We construct a quasi-periodic orbit with three frequencies; the
frequency of the unperturbed circular rotation (slow) and the two fast
frequencies of two mutually orthogonal harmonic modes of the variational
dynamics. Poynting's theorem gives a simple mechanism for a beat of two
mutually orthogonal fast modes to cancel the radiation of the unperturbed
circular motion by interference. This mechanism operates when the two fast
frequencies beat at the circular frequency, a no-radiation condition. The
resonant orbits turn out to have unperturbed orbital angular momenta that are
integer multiples of Planck's constant to a good approximation. This dynamics
displays many qualitative agreements with quantum electrodynamics (QED); (i)
the unperturbed frequency of each resonant orbit agrees with a corresponding
emission line of QED within a few percent on average (ii) the unperturbed
orbital frequency of a resonant orbit is given by a difference of two linear
eigenvalues (the frequencies of the mutually orthogonal fast modes) and (iii)
the averaged angular momentum of gyration is of the order of Planck's constant.


title:
A New Option for a Search for Alpha Variation: Narrow Transitions with
  Enhanced Sensitivity

abstract:
  We consider several transitions between narrow lines that have an enhanced
sensitivity to a possible variation of the fine structure constant, alpha. This
enhancement may allow a search to be performed with an effective suppression of
the systematic sources of uncertainty that are unavoidable in conventional
high-resolution spectroscopic measurements. In the future this may provide the
strongest laboratory constraints on alpha variation.


title: Time evolution of link length distribution in PRL collaboration network

abstract:
  An important aspect of a Euclidean network is its link length distribution,
studied in a few real networks so far. We compute the distribution of the link
lengths between collaborators whose papers appear in the PhysicalReview Letters
(PRL) in several years within a range of four decades. The distribution is
non-monotonic; there is a peak at nearest neighbour distances followed by a
sharp fall and a subsequent rise at larger distances. The behaviour of the
statistical properties of the distribution with time indicates that
collaborations might become distance independent in about thirty to forty
years.


title:
Fits, and especially linear fits, with errors on both axes, extra
  variance of the data points and other complications

abstract:
  The aim of this paper, triggered by some discussions in the astrophysics
community raised by astro-ph/0508529, is to introduce the issue of `fits' from
a probabilistic perspective (also known as Bayesian), with special attention to
the construction of model that describes the `network of dependences' (a
Bayesian network) that connects experimental observations to model parameters
and upon which the probabilistic inference relies. The particular case of
linear fit with errors on both axes and extra variance of the data points
around the straight line (i.e. not accounted by the experimental errors) is
shown in detail. Some questions related to the use of linear fit formulas to
log-linearized exponential and power laws are also sketched, as well as the
issue of systematic errors.


title:
Transport coefficients for electrolytes in arbitrarily shaped nano and
  micro-fluidic channels

abstract:
  We consider laminar flow of incompressible electrolytes in long, straight
channels driven by pressure and electro-osmosis. We use a Hilbert space
eigenfunction expansion to address the general problem of an arbitrary cross
section and obtain general results in linear-response theory for the hydraulic
and electrical transport coefficients which satisfy Onsager relations. In the
limit of non-overlapping Debye layers the transport coefficients are simply
expressed in terms of parameters of the electrolyte as well as the geometrical
correction factor for the Hagen-Poiseuille part of the problem. In particular,
we consider the limits of thin non-overlapping as well as strongly overlapping
Debye layers, respectively, and calculate the corrections to the hydraulic
resistance due to electro-hydrodynamic interactions.


title:
Characterization of charge collection in CdTe and CZT using the
  transient current technique

abstract:
  The charge collection properties in different particle sensor materials with
respect to the shape of the generated signals, the electric field within the
detector, the charge carrier mobility and the carrier lifetime are studied with
the transient current technique (TCT). Using the well-known properties of Si as
a reference, the focus is laid on Cadmium-Telluride (CdTe) and
Cadmium-Zinc-Telluride (CZT), which are currently considered as promising
candidates for the efficient detection of X-rays. All measurements are based on
a transient-current technique (TCT) setup, which allows the recording of
current pulses generated by an 241Am alpha-source. These signals will be
interpreted with respect to the build-up of space-charges inside the detector
material and the subsequent deformation of the electric field. Additionally the
influence of different electrode materials (i.e. ohmic or Schottky contacts) on
the current pulse shapes will be treated in the case of CdTe. Finally, the
effects of polarization, i.e. the time-dependent degradation of the detector
signals due to the accumulation of fixed charges within the sensor, are
presented.


title:
Introducing the notion of bare and effective mass via Newton's second
  law of motion

abstract:
  The concepts of bare and effective mass are widely used within modern
physics. Their meaning is discussed in advanced undergraduate and graduate
courses such as solid state physics, nuclear physics and quantum field theory.
Here, I discuss how these concepts may be introduced, at a very early stage,
together with the discussion of Newton's second law of motion for a sliding
block. The setting up of a simple equation for the effective mass will allow
instructors to discuss how external parameters, such as the temperature,
influence this quantity. By developing the same equation as a power series one
may also discuss perturbation theory and introduce Feynman diagrams.

categories: physics.ed-ph cond-mat.other hep-th physics.class-ph


title:
Reply to Comment on "The origin of bursts and heavy tails in human
  dynamics"

abstract:
  Understanding human dynamics is of major scientific and practical importance
and can be increasingly addressed in a quantitative fashion thanks to
electronic records capturing various human activity patterns. The authors of
Ref. [1] revisit the datasets studied in Ref. [2], making four technical
observations. Some of the observations of Ref. [1] are based on the authors'
unfamiliarity with the details of the data collection process and have little
relevance to the findings of Ref. [2] and others are resolved in quantitative
fashion by other authors [3].


title:
Observation of individual molecules trapped on a nanostructured
  insulator

abstract:
  For the first time, ordered polar molecules confined in monolayer-deep
rectangular pits produced on an alkali halide surface by electron irradiation
have been resolved at room temperature by non-contact atomic force microscopy.
Molecules self-assemble in a specific fashion inside pits of width smaller than
15 nm. By contrast no ordered aggregates of molecules are observed on flat
terraces. Conclusions regarding nucleation and ordering mechanisms are drawn.
Trapping in pits as small as 2 nm opens a route to address single molecules.


title:
Networks between Professionals and Society: A Model for Protein
  Dependency

abstract:
  We propose a network model with a fixed number of nodes and links with a
dynamics which favors links between nodes differing in connectivity. Parameter
regimes where the degree distributions follow power-laws, P(k) ~ k^-gamma, high
clustering following C(N) ~ 1/N and small-world properties, with a network
diameter following D(N) ~ A+ B log N, are observed. Our model gives results
comparable with real-world protein networks.


title:
Attosecond light pulses to reveal the time-dependent rovibrational
  motion of the correlated electron pair in helium

abstract:
  We illustrate how attosecond light pulses can be used to directly mapping out
the time-dependence of the correlated motion of two excited atomic electrons,
discuss how the two-electron correlations manifest themselves in realistic
attosecond measurements, and propose the following for experimental
exploration:
  (a) The single ionization signals which directly reveal bending-vibrational
motion of the correlated electron pair,
  (b) and also its rotational motion.
  (c) The double ionization signals which directly reveal the two-electron
density in momentum space. To facilitate the description of the above points,
use is made of simple wave packets of doubly-excited states of helium.


title:
Isotopic replacement in ionic systems: the 4He2+ + 3He -> 3He4He+ + 4He
  reaction

abstract:
  Full quantum dynamics calculations have been carried out for the ionic
reaction 4He2+ + 3He and state-to-state reactive probabilities have been
obtained using both a time-dependent (TD) and a time-independent (TI) approach.
An accurate ab-initio potential energy surface has been employed for the
present quantum dynamics and the two sets of results are shown to be in
agreement with each other. The results for zero total angular momentum suggest
a marked presence of atom exchange (isotopic replacement) reaction with
probabilities as high as 60%. The reaction probabilities are only weakly
dependent on the initial vibrational state of the reactants while they are
slightly more sensitive to the degree of rotational excitation. A brief
discussion of the results for selected higher total angular momentum values is
also presented, while the l-shifting approximation [1] has been used to provide
estimates of the total reaction rates for the title process. Such rates are
found to be large enough to possibly become experimentally accessible.


title: The Production Function

abstract:
  Productions functions map the inputs of a firm or a productive system onto
its outputs. This article expounds generalizations of the production function
that include state variables, organizational structures and increasing returns
to scale. These extensions are needed in order to explain the regularities of
the empirical distributions of some economic variables.


title:
Localization of magnetic sources underground by a data adaptive
  tomographic scanner

abstract:
  A tomography method is proposed to image magnetic anomaly sources buried
below a non-flat ground surface, by developing the expression of the total
power associated with a measured magnetic field. By discretising the integral
relating a static magnetic field to its source terms, the total power can be
written as a sum of crosscorrelation products between the magnetic field data
set and the theoretical expression of the magnetic field generated by a source
element of unitary strength. Then, applying Schwarz's inequality, an occurrence
probability function is derived for imaging any distribution of magnetic
anomaly sources in the subsurface. The tomographic procedure consists in
scanning the half-space below the survey area by the unitary source and in
computing the occurrence probability function at the nodes of a regular grid
within the half-space. The grid values are finally contoured in order to single
out the zones with high probability of occurrence of buried magnetic anomaly
sources. Synthetic and field examples are discussed to test the resolution
power of the proposed tomography.


title: Theory of emission from an active photonic lattice

abstract:
  The emission from a radiating source embedded in a photonic lattice is
calculated. The analysis considers the photonic lattice and free space as a
combined system. Furthermore, the radiating source and electromagnetic field
are quantized. Results show the deviation of the photonic lattice spectrum from
the blackbody distribution, with intracavity emission suppressed at certain
frequencies and enhanced at others. In the presence of rapid population
relaxation, where the photonic lattice and blackbody populations are described
by the same equilibrium distribution, it is found that the enhancement does not
result in output intensity exceeding that of the blackbody at the same
frequency. However, for slow population relaxation, the photonic lattice
population has a greater tendency to deviate from thermal equilibrium,
resulting in output intensities exceeding those of the blackbody, even for
identically pumped structures.


title: Dynamics of Social Systems: Cooperation and Free-Riding

abstract:
  We study the mean field dynamics of a model introduced by Phan et al [Wehia,
2005] of a polymorphic social community. The individuals may choose between
three strategies: either not to join the community or, in the case of joining
it, to cooperate or to behave as a free-rider. Individuals' preferences have an
idiosyncratic component and a social component. Cooperators bear a fixed cost
whereas free-riders support a cost proportional to the number of cooperators.
We study the dynamics of this model analytically in the mean field
approximation for both parallel and sequential updating. As we vary one of the
parameters while keeping the other parameters fixed, the phase diagram
experiences a rich class of bifurcations. Noticeably, a limit cycle is shown to
exist in both parallel and sequential updating, under certain parameter
settings. A comparison of the analytical predictions with computer simulation
is also included.


title:
Nonlinear evolution of the plasma beatwave: Compressing the laser
  beatnotes via electromagnetic cascading

abstract:
  The near-resonant beatwave excitation of an electron plasma wave (EPW) can be
employed for generating the trains of few-femtosecond electromagnetic (EM)
pulses in rarefied plasmas. The EPW produces a co-moving index grating that
induces a laser phase modulation at the difference frequency. The bandwidth of
the phase-modulated laser is proportional to the product of the plasma length,
laser wavelength, and amplitude of the electron density perturbation. The laser
spectrum is composed of a cascade of red and blue sidebands shifted by integer
multiples of the beat frequency. When the beat frequency is lower than the
electron plasma frequency, the red-shifted spectral components are advanced in
time with respect to the blue-shifted ones near the center of each laser
beatnote. The group velocity dispersion of plasma compresses so chirped
beatnotes to a few-laser-cycle duration thus creating a train of sharp EM
spikes with the beat periodicity. Depending on the plasma and laser parameters,
chirping and compression can be implemented either concurrently in the same, or
sequentially in different plasmas. Evolution of the laser beatwave end electron
density perturbations is described in time and one spatial dimension in a
weakly relativistic approximation. Using the compression effect, we demonstrate
that the relativistic bi-stability regime of the EPW excitation [G. Shvets,
Phys. Rev. Lett. 93, 195004 (2004)] can be achieved with the initially
sub-threshold beatwave pulse.


title:
Single-Cycle High-Intensity Electromagnetic Pulse Generation in the
  Interaction of a Plasma Wakefield with Nonlinear Coherent Structures

abstract:
  The interaction of coherent nonlinear structures (such as sub-cycle solitons,
electron vortices and wake Langmuir waves) with a strong wake wave in a
collisionless plasma can be exploited in order to produce ultra-short
electromagnetic pulses. The electromagnetic field of a coherent nonlinear
structure is partially reflected by the electron density modulations of the
incident wake wave and a single-cycle high-intensity electromagnetic pulse is
formed. Due to the Doppler effect the length of this pulse is much shorter than
that of the coherent nonlinear structure. This process is illustrated with
two-dimensional Particle-in-Cell simulations. The considered laser-plasma
interaction regimes can be achieved in present day experiments and can be used
for plasma diagnostics.


title:
Non-perturbative approach to high-index-contrast variations in
  electromagnetic systems

abstract:
  We present a method that formally calculates \emph{exact} frequency shifts of
an electromagnetic field for arbitrary changes in the refractive index. The
possible refractive index changes include both anisotropic changes and boundary
shifts. Degenerate eigenmode frequencies pose no problems in the presented
method. The approach relies on operator algebra to derive an equation for the
frequency shifts, which eventually turn out in a simple and physically sound
form. Numerically the equations are well-behaved, easy implementable, and can
be solved very fast. Like in perturbation theory a reference system is first
considered, which then subsequently is used to solve another related, but
different system. For our method precision is only limited by the reference
system basis functions and the error induced in frequency is of second order
for first-order basis set error. As an example we apply our method to the
problem of variations in the air-hole diameter in a photonic crystal fiber.


title: Dipole trap for 87 Rb atoms using lasers of different wavelength

abstract:
  The parity of atomic wave functions prevents neutral atoms from having
permanent electric-dipole moment. Electric-dipole moment is induced in an atom
when exposed to strong light, the electric field of the light. Hence the
optical trapping of neutral atoms relies on the induced dipole moment. Here we
present the calculated numerical values of the detuning, potential depth,
minimum laser power required to trap $^{87}$Rb ($D_2$ line) atoms using lasers
of wavelength 1064 nm, 850 nm, 820 nm and 800 nm and beam waists 50$\mu$m,
100$\mu$m and 200$\mu$m.


title:
Calculations of energy levels and lifetimes of low-lying states of
  barium and radium

abstract:
  We use the configuration interaction method and many-body perturbation theory
to perform accurate calculations of energy levels, transition amplitudes, and
lifetimes of low-lying states of barium and radium. Calculations for radium are
needed for the planning of measurements of parity and time invariance violating
effects which are strongly enhanced in this atom. Calculations for barium are
used to control the accuracy of the calculations.


title: Random walk, cluster growth, and the morphology of urban conglomerations

abstract:
  We propose a new model of cluster growth according to which the probability
that a new unit is placed in a point at a distance $r$ from the city center is
a Gaussian with mean equal to the cluster radius and variance proportional to
the mean, modulated by the local density $\rho(r)$. The model is analytically
solvable in $d=2$ dimensions, where the density profile varies as a
complementary error function. The model reproduces experimental observations
relative to the morphology of cities, determined via an original analysis of
digital maps with a very high spatial resolution, and helps understanding the
emergence of vehicular traffic.


title: Strategies for fast convergence in semiotic dynamics

abstract:
  Semiotic dynamics is a novel field that studies how semiotic conventions
spread and stabilize in a population of agents. This is a central issue both
for theoretical and technological reasons since large system made up of
communicating agents, like web communities or artificial embodied agents teams,
are getting widespread. In this paper we discuss a recently introduced simple
multi-agent model which is able to account for the emergence of a shared
vocabulary in a population of agents. In particular we introduce a new
deterministic agents' playing strategy that strongly improves the performance
of the game in terms of faster convergence and reduced cognitive effort for the
agents.

categories: physics.soc-ph cond-mat.stat-mech cs.GT cs.MA


title:
Ordering Algorithms and Confidence Intervals in the Presence of Nuisance
  Parameters

abstract:
  We discuss some issues arising in the evaluation of confidence intervals in
the presence of nuisance parameters (systematic uncertainties) by means of
direct Neyman construction in multi-dimensional space. While this kind of
procedure provides rigorous coverage, it may be affected by large overcoverage,
and/or produce results with counterintuitive behavior with respect to the
uncertainty on the nuisance parameters, or other undesirable properties. We
describe a choice of ordering algorithm that provides results with good general
properties, the correct behavior for small uncertainties, and limited
overcoverage.


title:
Subgrid-scale modeling of reacting scalar fluxes in large-eddy
  simulations of atmospheric boundary layers

abstract:
  In large-eddy simulations of atmospheric boundary layer turbulence, the
lumped coefficient in the eddy-diffusion subgrid-scale (SGS) model is known to
depend on scale for the case of inert scalars. This scale dependence is
predominant near the surface. In this paper, a scale-dependent dynamic SGS
model for the turbulent transport of reacting scalars is implemented in
large-eddy simulations of a neutral boundary layer. Since the model coefficient
is computed dynamically from the dynamics of the resolved scales, the
simulations are free from any parameter tuning. A set of chemical cases
representative of various turbulent reacting flow regimes is examined. The
reactants are involved in a first-order reaction and are injected in the
atmospheric boundary layer with a constant and uniform surface flux. Emphasis
is placed on studying the combined effects of resolution and chemical regime on
the performance of the SGS model. Simulations with the scale-dependent dynamic
model yield the expected trends of the coefficients as function of resolution,
position in the flow and chemical regime, leading to resolution-independent
turbulent reactant fluxes.


title: Fluctuation of magnetic induction in von K\'arm\'an swirling flows

abstract:
  Studies of magnetic induction in von K\'arm\'an swirling flows have so far
linked the time-averaged induced magnetic field to the structure of the mean
flow. They have evidenced the Omega and Parker mechanism generated respectively
by the flow differential rotation and helicity, which underly the Duddley and
James \cite{DuddleyJames} dynamos. Using an array of Hall probes we study here
the dynamical regime. In the experimental flow, turbulence is fully developed
and large fluctuations are observed in the magnetic induction processes. We
find that the large scale turbulent fluctuations have different characteristics
when induction results from the differential rotation or from the dynamics of
the stagnation point in the mid plane of the von K\'arm\'an flow. Symmetry
considerations indicate that the dynamical flow spends half of its time away
from the time-averaged structure. The consequences of these observations for
dynamo experiments are discussed.


title:
Random Phase Approximation For allowed and Parity Non-conserving
  Electric Dipole Transition Amplitudes and its connection with Many-Body
  Perturbation Theory and Coupled Cluster Theory

abstract:
  The connections between the Random Phase Approximation (RPA) and Many-Body
Perturbation Theory (MBPT) and its all order generalisation, the Coupled-
Cluster Theory (CCT) have been explored. Explicit expressions have been derived
for the electric dipole amplitudes for allowed and forbidden transitions
induced by the parity non-conserving neutral weak interaction. The Goldstone
diagrams associated with the RPA terms in both cases are shown to arise in MBPT
and CCT and the numerical verification of this relationship is made for the
allowed electric dipole transitions.


title:
Comparison of the Hirsch-index with standard bibliometric indicators and
  with peer judgment for 147 chemistry research groups

abstract:
  In this paper we present characteristics of the statistical correlation
between the Hirsch (h-) index and several standard bibliometric indicators, as
well as with the results of peer review judgment. We use the results of a large
evaluation study of 147 university chemistry research groups in the Netherlands
covering the work of about 700 senior researchers during the period 1991-2000.
Thus, we deal with research groups rather than individual scientists, as we
consider the research group as the most important work floor unit in research,
particularly in the natural sciences. Furthermore, we restrict the citation
period to a three-year window instead of life time counts in order to focus on
the impact of recent work and thus on current research performance. Results
show that the h-index and our bibliometric crown indicator both relate in a
quite comparable way with peer judgments. But for smaller groups in fields with
less heavy citation traffic the crown indicator appears to be a more
appropriate measure of research performance.


title:
Simple derivation of dyadic Green functions of a simply moving,
  isotropic, dielectric-magnetic medium

abstract:
  Dyadic Green functions for time-harmonic fields in a homogeneous, isotropic,
dielectric-magnetic medium, moving with constant velocity, are derived by first
implementing a simple transformation and then using the dyadic Green functions
available for uniaxial dielectric-magnetic mediums.


title:
Physical and Mathematical Properties of a Quasi-Geostrophic Model of
  Intermediate Complexity of the Mid-Latitudes Atmospheric Circulation

abstract:
  A quasi-geostrophic intermediate complexity model is considered, providing a
schematic representation of the baroclinic conversion processes which
characterize the physics of the mid-latitudes atmospheric circulation. The
model is relaxed towards a given latitudinal temperature profile, which acts as
baroclinic forcing, controlled by a parameter TE determining the forced
equator-to-pole temperature gradient. As TE increases, a transition takes place
from a stationary regime to a periodic regime, and eventually to an earth-like
chaotic regime where evolution takes place on a strange attractor. The
dependence of the attractor dimension, metric entropy, and bounding box volume
in phase space is studied by varying both TE and model resolution. The
statistical properties of observables having physical relevance, namely the
total energy of the system and the latitudinally averaged zonal wind, are also
examined. It is emphasized that while the attractor's properties are quite
sensitive to model resolution, the global physical observables depend less
critically on it. For more detailed physical observables, such as the
latitudinal profiles of the zonal wind, model resolution again may be critical:
the effectiveness of the zonal wind convergence, acting as barotropic
stabilization of the baroclinic waves, heavily relies on the details of the
latitudinal structure of the fields. The necessity and complementarity of both
the dynamical systems and physical approach is underlined.

categories: physics.ao-ph nlin.CD physics.comp-ph physics.flu-dyn physics.geo-ph


title: The LHC, shining light on the Dark Side

abstract:
  Starting in the summer of 2007, the Large Hadron Collider (LHC) will collide
proton beams at center-of-mass energies of 14 TeV exceeding by a factor of ten
what was previously achieved. It will be located in the 27km long underground
tunnel, in which the Large Electron Positron collider (LEP) was working until
the year 2000. The Large Hadron Collider is a part of the accelerator complex
of the European Laboratory of Particle Physics (CERN), situated on the
Franco-Swiss border close to Geneva.


title: Orthogonal-Phase-Velocity Propagation of Electromagnetic Plane Waves

abstract:
  In an isotropic, homogeneous, nondissipative, dielectric-magnetic medium that
is simply moving with respect to an inertial reference frame, planewave
solutions of the Maxwell curl postulates can be such that the phase velocity
and the time-averaged Poynting vector are mutually orthogonal.
Orthogonal-phase-velocity propagation thus adds to the conventional
positive-phase-velocity propagation and the recently discovered
negative-phase-velocity propagation that is associated with the phenomenon of
negative refraction.


title:
Hydration process of multi-stacked phospholipid bilayers to form giant
  vesicles

abstract:
  The hydration process of multi-stacked phospholipid bilayers to form giant
vesicles was investigated by time-resolved small angle X-ray scattering. The
hydration of lipids in the liquid-crystalline phase was found to proceed in two
stages. In the early stage, until about 100 s after hydration, lipid bilayers
on a solid substrate swell about 12 $\rm{\AA}$ and reach a quasi-stable state.
In the late stage, after several hundreds of seconds, lipid bilayers gradually
peel off from the stack. On the other hand, in the case of a lipid in the gel
phase, only the early stage is observed. These behaviors correspond to the
capacity for the giant vesicle formation depending on the lipid phases. The
kinetics of the peeling-off process is discussed in terms of Kramers' formulas.


title: Advanced Photodetectors for Hyperspectroscopy and Other Applications

abstract:
  Hyperspectroscopy is a new method of surface image taking, providing
simultaneously high position and spectral resolutions which allow one to make
some conclusions about chemical compositions of the surfaces. We are now
studying applications of the hyperspctroscopic technique to be used for
medicine. This may allow one to develop early diagnostics of some illnesses, as
for example, skin cancer. For image taking advanced MCPs are currently used,
sensitive in the spectral interval of 450-850 nm. One of the aims of this work
is to extend the hyperspectrocpic method to the UV region of spectra: 185-280
nm. For this we have developed and successfully tested innovative 1D and 2D UV
sealed photosensitive gaseous detectors with resistive electrodes. These
detectors are superior MCPs due to the very low rate of noise pulses and thus
due to the high signal to noise ratio. Other important features of these
detectors are that they have excellent position resolutions - 30 micron in
digital form, are vibration stable and are spark protected. The first results
from the application of these detectors for spectroscopy, hyperspectroscopy and
the flame detection are presented.


title: Low vorticity and small gas expansion in premixed flames

abstract:
  Different approaches to the nonlinear dynamics of premixed flames exist in
the literature: equations based on developments in a gas ex- pansion parameter,
weak nonlinearity approximation, potential model equation in a coordinate-free
form. However the relation between these different equations is often unclear.
Starting here with the low vor- ticity approximation proposed recently by one
of the authors, we are able to recover from this formulation the dynamical
equations usually obtained at the lowest orders in gas expansion for plane on
average flames, as well as obtain a new second order coordinate-free equation
extending the potential flow model known as the Frankel equation. It is also
common to modify gas expansion theories into phenomelogical equations, which
agree quantitatively better with numerical simula- tions. We discuss here what
are the restrictions imposed by the gas expansion development results on this
process.


title:
Zero-spin-photon hypothesis: `Zero-spin-photon generation in
  pair-production and its subsequent decay into neutrino and antineutrino' -
  solves many-riddles of physics and universe

abstract:
  `What is work and what is heat' is re-investigated from the perspective of
second law of thermodynamics. It is shown that the inevitable consequence of
second law of thermodynamics and spin conservation necessitates the possible
generation of zero spin photon in pair production process, and its subsequent
decay explains the birth of neutrino and antineutrino. The proposed
neutrino-genesis, solves many riddles of physics and universe. The riddles
considered and explained are about: (i) mysterious neutrino (and antineutrino)
and its bizarre properties such as handed-ness and parity-violation, (ii)
questionable asymmetry/ excess of matter over antimatter, (iii) possibility of
existence of antimatter world and (iv) parity (P) violation and aspects of CP
and CPT violation or restoration in the universe.


title: The Network of Collaboration Among Rappers and its Community Structure

abstract:
  The social network formed by the collaboration between rappers is studied
using standard statistical techniques for analyzing complex networks. In
addition, the community structure of the rap music community is analyzed using
a new method that uses weighted edges to determine which connections are most
important and revealing among all the communities. The results of this method
as well as possible reasons for the structure of the rap music community are
discussed.


title: Zipf Law for Brazilian Cities

abstract:
  This work studies the Zipf Law for cities in Brazil. Data from censuses of
1970, 1980, 1991 and 2000 were used to select a sample containing only cities
with 30,000 inhabitants or more. The results show that the population
distribution in Brazilian cities does follow a power law similar to the ones
found in other countries. Estimates of the power law exponent were found to be
2.22 +/- 0.34 for the 1970 and 1980 censuses, and 2.26 +/- 0.11 for censuses of
1991 and 2000. More accurate results were obtained with the maximum likelihood
estimator, showing an exponent equal to 2.41 for 1970 and 2.36 for the other
three years.

categories: physics.soc-ph cond-mat.stat-mech nlin.AO nlin.PS


title: Computing stationary free-surface shapes in microfluidics

abstract:
  A finite-element algorithm for computing free-surface flows driven by
arbitrary body forces is presented. The algorithm is primarily designed for the
microfluidic parameter range where (i) the Reynolds number is small and (ii)
force-driven pressure and flow fields compete with the surface tension for the
shape of a stationary free surface. The free surface shape is represented by
the boundaries of finite elements that move according to the stress applied by
the adjacent fluid. Additionally, the surface tends to minimize its free energy
and by that adapts its curvature to balance the normal stress at the surface.
The numerical approach consists of the iteration of two alternating steps: The
solution of a fluidic problem in a prescribed domain with slip boundary
conditions at the free surface and a consecutive update of the domain driven by
the previously determined pressure and velocity fields. ...


title:
Quantum Features of Vacuum Flux Impact: An Interpretation of Quantum
  Phenomena

abstract:
  Special relativity combined with the stochastic vacuum flux impact model lead
to an explicit interpretation of many of the phenomena of elementary quantum
mechanics. We examine characteristics of a repetitively impacted submicroscopic
particle in conjunction with examination of the ways in which effects
associated with the particle's behavior appear in moving frames of reference.
As seen from relatively moving frames of reference, the time and location of
impacts and recoils automatically exhibit wave behavior. This model leads to
free particle waves with frequencies proportional to the energy and wavelengths
inversely proportional to the momentum. As seen from relatively moving frames
of reference, impacts and their associated recoils can appear to an observer to
take place simultaneously at multiple locations in space. For superposed free
particle waves corresponding to bidirectional motion, an amplitude that varies
sinusoidally with distance results. A governing equation identical in form to
the Schroedinger equation is developed that describes the behavior of the
impacts and their associated recoils. This approach permits many features of
quantum mechanics to be examined within an intuitively visualizable framework.