title:
Differential Equations on Complex Projective Hypersurfaces of Low
  Dimension

abstract:
  Let $n=2,3,4,5$ and let $X$ be a smooth complex projective hypersurface of
$\mathbb P^{n+1}$. In this paper we find an effective lower bound for the
degree of $X$, such that every holomorphic entire curve in $X$ must satisfy an
algebraic differential equation of order $k=n=\dim X$, and also similar bounds
for order $k>n$. Moreover, for every integer $n\ge 2$, we show that there are
no such algebraic differential equations of order $k<n$ for a smooth
hypersurface in $\mathbb P^{n+1}$.


title:
Two theorems that relate discrete stochastic processes to microscopic
  mechanics

abstract:
  Starting from a classical mechanics of a ``colloid particle'' and $N$ ``water
molecules'', we study effective stochastic dynamics of the particle which jumps
between deep potential wells. We prove that the effective transition
probability satisfies (local) detailed balance condition. This enables us to
rigorously determine precise form of the transition probability when barrier
potentials have certain regularity and symmetry.


title: Polynomial functors and opetopes

abstract:
  We give an elementary and direct combinatorial definition of opetopes in
terms of trees, well-suited for graphical manipulation and explicit
computation. To relate our definition to the classical definition, we recast
the Baez-Dolan slice construction for operads in terms of polynomial monads:
our opetopes appear naturally as types for polynomial monads obtained by
iterating the Baez-Dolan construction, starting with the trivial monad. We show
that our notion of opetope agrees with Leinster's. Next we observe a suspension
operation for opetopes, and define a notion of stable opetopes. Stable opetopes
form a least fixpoint for the Baez-Dolan construction. A final section is
devoted to example computations, and indicates also how the calculus of
opetopes is well-suited for machine implementation.


title: Infinite-dimensional diffusions as limits of random walks on partitions

abstract:
  The present paper originated from our previous study of the problem of
harmonic analysis on the infinite symmetric group. This problem leads to a
family {P_z} of probability measures, the z-measures, which depend on the
complex parameter z. The z-measures live on the Thoma simplex, an
infinite-dimensional compact space which is a kind of dual object to the
infinite symmetric group. The aim of the paper is to introduce stochastic
dynamics related to the z-measures. Namely, we construct a family of diffusion
processes in the Toma simplex indexed by the same parameter z. Our diffusions
are obtained from certain Markov chains on partitions of natural numbers n in a
scaling limit as n goes to infinity. These Markov chains arise in a natural
way, due to the approximation of the infinite symmetric group by the increasing
chain of the finite symmetric groups. Each z-measure P_z serves as a unique
invariant distribution for the corresponding diffusion process, and the process
is ergodic with respect to P_z. Moreover, P_z is a symmetrizing measure, so
that the process is reversible. We describe the spectrum of its generator and
compute the associated (pre)Dirichlet form.


title:
Comment on "Electromagnetic Global Gyrokinetic Simulation of Shear
  Alfven Wave Dynamics in Tokamak Plasmas" [Phys. Plasmas 14, 042503 (2007)]

abstract:
  This comment clarifies the relation of the research in a recently published
article [Phys. Plasmas 14, 042503 (2007)] to other prior publications
addressing the inclusion of electromagnetic and drift-kinetic electron physics
in gyrokinetic simulation, raises a concern related to the inclusion of kinetic
electrons in a system with magnetic shear, and discusses alternatives in the
face of an important limitation on the general applicability of the algorithm
described therein.


title: Transfer matrices for piecewise constant potentials

abstract:
  By expressing the time-independent Schrodinger equation in one dimension as a
system of two first-order differential equations, the transfer matrix for a
rectangular potential barrier is obtained making use of the matrix exponential.
It is shown that the transfer matrix allows one to find the bound states and
the quasinormal modes. A similar treatment for the one-dimensional propagation
of electromagnetic waves in a homogeneous medium is also presented.


title: Local Structure of Ideal Shapes of Knots, II, Constant Curvature Case

abstract:
  The thickness, NIR(K) of a knot or link K is defined to be the radius of the
largest solid tube one can put around the curve without any self intersections,
which is also known as the normal injectivity radius of K. For C^{1,1} curves
K, NIR(K)=min{(1/2)DCSC(K),(1/(supkappa(K))))}, where kappa(K) is the
generalized curvature, and the double critical self distance DCSD(K) is the
shortest length of the segments perpendicular to K at both end points. The
knots and links in ideal shapes (or tight knots or links) belong to the minima
of ropelength = length/thickness within a fixed isotopy class. In this article,
we prove that NIR(K)=(1/2)DCSC(K), for every relative minimum K of ropelength
in R^n for certain dimensions n, including n=3.


title:
Discrimination of the binary coherent signal: Gaussian-operation limit
  and simple non-Gaussian near-optimal receivers

abstract:
  We address the limit of the Gaussian operations and classical communication
in the problem of quantum state discrimination. We show that the optimal
Gaussian strategy for the discrimination of the binary phase shift keyed (BPSK)
coherent signal is a simple homodyne detection. We also propose practical
near-optimal quantum receivers that beat the BPSK homodyne limit in all areas
of the signal power. Our scheme is simple and does not require realtime
electrical feedback.


title: Form Factors in the radiative pion decay

abstract:
  We perform an analysis of the form factors that rule the structure-dependent
amplitude in the radiative pion decay. The resonance contributions to pion -> e
nu_e gamma decays are computed through the proper construction of the vector
and axial-vector form factors by setting the QCD driven asymptotic properties
of the three-point Green functions VVP and VAP, and by demanding the smoothing
of the form factors at high transfer of momentum. A comparison between
theoretical and experimental determinations of the form factors is also carried
out. We also consider and evaluate the role played by a non-standard tensor
form factor. We conclude that, at present and due to the hadronic incertitudes,
the search for New Physics in this process is not feasible.


title: H$_2$D$^+$ line emission in Proto-Planetary Disks

abstract:
  %Context: {Previous studies have indicated that the 372.4 GHz ground
transition of ortho-H$_2$D$^+$ might be a powerful probe of Proto-Planetary
Disks. The line could be especially suited for study of the disk mid-plane,
where the bulk of the mass resides and where planet formation takes place.}
%Aims: {Provide detailed theoretical predictions for the line intensity,
profile and maps expected for representative disk models.} %Methods: {We
determine the physical and chemical structure of the disks from the model
developed by Ceccarelli & Dominik (2005). The line emission is computed with
the new radiative transfer method developed recently by Elitzur & Asensio Ramos
(2006).} %Results: {We present intensity maps convolved with the expected ALMA
resolution, which delineate the origin of the H$_2$D$^+$ 372.4 GHz line. In the
disk inner regions, the line probes the conditions in the mid-plane out to
radial distances of a few tens of AU, where Solar-like planetary systems might
form. In the disk outermost regions, the line originates from slightly above
the mid-plane. When the disk is spatially resolved, the variation of line
profile across the image provides important information about the velocity
field. Spectral profiles of the entire disk flux show a double peak shape at
most inclination angles.} %Conclusions: {Our study confirms that the 372.4 GHz
H$_2$D$^+$ line provides powerful diagnostics of the mid-plane of
Proto-Planetary Disks. Current submillimeter telescopes are capable of
observing this line, though with some difficulties. The future ALMA
interferometer will have the sensitivity to observe and even spatially resolve
the H$_2$D$^+$ line emission.}


title: Spectroscopy of Ultracold, Trapped Cesium Feshbach Molecules

abstract:
  We explore the rich internal structure of Cs_2 Feshbach molecules. Pure
ultracold molecular samples are prepared in a CO_2-laser trap, and a multitude
of weakly bound states is populated by elaborate magnetic-field ramping
techniques. Our methods use different Feshbach resonances as input ports and
various internal level crossings for controlled state transfer. We populate
higher partial-wave states of up to eight units of rotational angular momentum
(l-wave states). We investigate the molecular structure by measurements of the
magnetic moments for various states. Avoided level crossings between different
molecular states are characterized through the changes in magnetic moment and
by a Landau-Zener tunneling method. Based on microwave spectroscopy, we present
a precise measurement of the magnetic-field dependent binding energy of the
weakly bound s-wave state that is responsible for the large background
scattering length of Cs. This state is of particular interest because of its
quantum-halo character.


title:
Dirac Magnetic Monopole Production from Photon Fusion in Proton
  Collisions

abstract:
  We calculate the lowest order cross--section for Dirac magnetic monopole
production from photon fusion in p p-bar collisions at sqrt{s}=1.96 TeV, p p
collisions at sqrt{s}=14 TeV, and we compare photon fusion with Drell--Yan (DY)
production. We find the total photon fusion cross--section is comparable with
DY at sqrt{s}=1.96 TeV and dominates DY by a factor ~50 at sqrt{s}=14 TeV. We
conclude that both the photon fusion and DY processes allow for a monopole mass
limit m>370 GeV based upon the null results of the recent monopole search at
the Collider Detector at Fermilab (CDF). We also conclude that photon fusion is
the leading production mechanism to be considered for direct monopole searches
at the Large Hadron Collider (LHC).


title: Lattice chirality and the decoupling of mirror fermions

abstract:
  We show, using exact lattice chirality, that partition functions of lattice
gauge theories with vectorlike fermion representations can be split into
"light" and "mirror" parts, such that the "light" and "mirror" representations
are chiral. The splitting of the full partition function into "light" and
"mirror" is well defined only if the two sectors are separately anomaly free.
We show that only then is the generating functional, and hence the spectrum, of
the mirror theory a smooth function of the gauge field background. This
explains how ideas to use additional non-gauge, high-scale mirror-sector
dynamics to decouple the mirror fermions without breaking the gauge
symmetry--for example, in symmetric phases at strong mirror Yukawa
coupling--are forced to respect the anomaly-free condition when combined with
the exact lattice chiral symmetry. Our results also explain a paradox posed by
a recent numerical study of the mirror-fermion spectrum in a toy
would-be-anomalous two-dimensional theory. In passing, we prove some general
properties of the partition functions of arbitrary chiral theories on the
lattice that should be of interest for further studies in this field.


title:
Structure and dynamics in glass-formers: predictability at large length
  scales

abstract:
  Dynamic heterogeneity in glass-formers has been related to their static
structure using the concept of dynamic propensity. We re-examine this
relationship by analyzing dynamical fluctuations in two atomistic glass-formers
and two theoretical models. We introduce quantitative statistical indicators
which show that the dynamics of individual particles cannot be predicted on the
basis of the propensity, nor by any structural indicator. However, the spatial
structure of the propensity field does have predictive power for the spatial
correlations associated with dynamic heterogeneity. Our results suggest that
the quest for a connection between static and dynamic properties of
glass-formers at the particle level is vain, but they demonstrate that such
connection does exist on larger length scales.


title:
Group gradings on simple Lie algebras of type A in positive
  characteristic

abstract:
  In this paper we consider gradings by a finite abelian group $G$ on the Lie
algebra $\mathfrak{sl}_n(F)$ over an algebraically closed field $F$ of
characteristic different from 2 and not dividing $n$.


title:
Multiscale expansion of the lattice potential KdV equation on functions
  of infinite slow-varyness order

abstract:
  We present a discrete multiscale expansion of the lattice potential
Korteweg-de Vries (lpKdV) equation on functions of infinite order of
slow-varyness. To do so we introduce a formal expansion of the shift operator
on many lattices holding at all orders. The lowest secularity condition from
the expansion of the lpKdV equation gives a nonlinear lattice equation,
depending on shifts of all orders, of the form of the nonlinear Schr\"odinger
(NLS) equation


title: The Dynamics-Based Approach to Studying Terrestrial Exoplanets

abstract:
  One of the great quests of astronomy is to obtain the spectrum of a
terrestrial planet orbiting within the habitable zone of its star, and the
dominant challenge in doing so is to isolate the light of the planet from that
of the star. Dynamics-based methods separate these signals temporally, whereas
imaging techniques do so spatially. In light of the overwhelming dominance of
dynamics-based methods over the past decade, we challenge the notion that
spectra of terrestrial planets necessarily require extreme imaging methods. We
advocate that some resources be committed to refining the proven technologies
of radial-velocity measurements, transit photometry, and occultation
spectroscopy (i.e. emergent infrared spectra obtained at secondary eclipse). We
see a particularly attractive opportunity in M-dwarfs, for which the habitable
zone is close to the star, increasing the probability and frequency of
transits, and the amplitude of the induced radial-velocity variation. Such
planets could be discovered by a dedicated ground-based transit survey of the
10,000 nearest M-dwarfs. The favorable planet-star contrast ratio would make
these planets ideal targets for the study of their atmospheres with the
technique of occultation spectroscopy.


title:
Estimates of the best Sobolev constant of the embedding of $BV(\Omega)$
  into $L^1(\partial\Omega)$ and related shape optimization problems

abstract:
  In this paper we find estimates for the optimal constant in the critical
Sobolev trace inequality $\lambda_1(\Omega)\|u\|_{L^1(\partial\Omega)} \le
\|u\|_{W^{1,1}(\Omega)}$ that are independent of $\Omega$. This estimates
generalize those of \cite{BS} concerning the $p$-Laplacian to the case $p=1$.
  We apply our results to prove existence of an extremal for this embedding. We
then study an optimal design problem related to $\lambda_1$, and eventually
compute the shape derivative of the functional $\Omega\to\lambda_1(\Omega)$. As
a consequence, we obtain that a ball of $\R^n$ of radius $n$ is critical for
volume-preserving deformations.


title:
The Evolution of Supernovae in Circumstellar Wind Bubbles II: Case of a
  Wolf-Rayet star

abstract:
  (Abridged) Mass-loss from massive stars leads to the formation of
circumstellar wind-blown bubbles surrounding the star, bordered by a dense
shell. When the star ends its life in a supernova (SN) explosion, the resulting
shock wave will interact with this modified medium. In a previous paper we
discussed the basic parameters of this interaction. In this paper we go a step
further and study the evolution of SNe in the wind blown bubble formed by a 35
$\msun$ star that starts off as an O star, goes through a red supergiant phase,
and ends its life as a Wolf-Rayet star. We model the evolution of the CSM and
then the expansion of the SN shock wave within this medium. Our simulations
clearly reveal fluctuations in density and pressure within the surrounding
medium. The SN shock interacting with these fluctuations, and then with the
dense shell surrounding the wind-blown cavity, gives rise to a variety of
transmitted and reflected shocks in the wind bubble. The interactions between
these various shocks and discontinuities is examined, and its effects on the
X-ray emission is noted. Our simulations reveal the presence of several
hydrodynamic instabilities. They show that the turbulent interior, coupled with
the large fluctuations in density and pressure, gives rise to an extremely
corrugated SN shock wave. The shock shows considerable wrinkles as it impacts
the dense shell, and the impact occurs in a piecemeal fashion, with some parts
of the shock wave interacting with the shell before the others. Therefore
different parts of the shell will `light-up' at different times. The
non-spherical nature of the interaction means that it will occur over a
prolonged period of time, and the spherical symmetry of the initial shock wave
is destroyed.


title:
The Discovery of an Active Galactic Nucleus in the Late-type Galaxy NGC
  3621: Spitzer Spectroscopic Observations

abstract:
  We report the discovery of an Active Galactic Nucleus (AGN) in the nearby SAd
galaxy NGC 3621 using Spitzer high spectral resolution observations. These
observations reveal the presence of [NeV] 14 um and 24 um emission which is
centrally concentrated and peaks at the position of the near-infrared nucleus.
Using the [NeV] line luminosity, we estimate that the nuclear bolometric
luminosity of the AGN is ~ 5 X 10^41 ergs s^-1, which corresponds based on the
Eddington limit to a lower mass limit of the black hole of ~ 4 X 10^3 Msun.
Using an order of magnitude estimate for the bulge mass based on the Hubble
type of the galaxy, we find that this lower mass limit does not put a strain on
the well-known relationship between the black hole mass and the host galaxy's
stellar velocity dispersion established in predominantly early-type galaxies.
Mutli-wavelength follow-up observations of NGC 3621 are required to obtain more
precise estimates of the bulge mass, black hole mass, accretion rate, and
nuclear bolometric luminosity. The discovery reported here adds to the growing
evidence that a black hole can form and grow in a galaxy with no or minimal
bulge.


title:
Improved Neural Modeling of Real-World Systems Using Genetic Algorithm
  Based Variable Selection

abstract:
  Neural network models of real-world systems, such as industrial processes,
made from sensor data must often rely on incomplete data. System states may not
all be known, sensor data may be biased or noisy, and it is not often known
which sensor data may be useful for predictive modelling. Genetic algorithms
may be used to help to address this problem by determining the near optimal
subset of sensor variables most appropriate to produce good models. This paper
describes the use of genetic search to optimize variable selection to determine
inputs into the neural network model. We discuss genetic algorithm
implementation issues including data representation types and genetic operators
such as crossover and mutation. We present the use of this technique for neural
network modelling of a typical industrial application, a liquid fed ceramic
melter, and detail the results of the genetic search to optimize the neural
network model for this application.


title:
Cavity Nonlinear Optics at Low Photon Numbers from Collective Atomic
  Motion

abstract:
  We report on Kerr nonlinearity and dispersive optical bistability of a
Fabry-Perot optical resonator due to the displacement of ultracold atoms
trapped within. In the driven resonator, such collective motion is induced by
optical forces acting upon up to $10^5$ $^{87}$Rb atoms prepared in the lowest
band of a one-dimensional intracavity optical lattice. The longevity of atomic
motional coherence allows for strongly nonlinear optics at extremely low cavity
photon numbers, as demonstrated by the observation of both branches of optical
bistability at photon numbers below unity.


title: Glimpsing through the high redshift neutral hydrogen fog

abstract:
  We analyze the transmitted flux in a sample of 17 QSOs spectra at
5.74<zem<6.42 to obtain tighter constraints on the volume-averaged neutral
hydrogen fraction, xHI, at z~6. We study separately the narrow transmission
windows (peaks) and the wide dark portions (gaps) in the observed absorption
spectra. By comparing the statistics of these spectral features with Lyalpha
forest simulations, we conclude that xHI evolves smoothly from 10^{-4.4} at
z=5.3 to 10^{-4.2} at z=5.6, with a robust upper limit xHI<0.36 at z=6.3. The
frequency and physical sizes of the peaks imply an origin in cosmic underdense
regions and/or in HII regions around faint quasars or galaxies. In one case
(the intervening HII region of the faint quasar RD J1148+5253 at z=5.70 along
the LOS of SDSS J1148+5251 at z=6.42) the increase of the peak spectral density
is explained by the first-ever detected transverse proximity effect in the HI
Lyalpha forest; this indicates that at least some peaks result from a locally
enhanced radiation field. We then obtain a strong lower limit on the foreground
QSO lifetime of tQ>11 Myr. The observed widths of the peaks are found to be
systematically larger than the simulated ones. Reasons for such discrepancy
might reside either in the photoionization equilibrium assumption or in
radiative transfer effects.


title:
The Compact X-ray Source 1E 1547.0-5408 and the Radio Shell
  G327.24-0.13: A New Proposed Association between a Candidate Magnetar and a
  Candidate Supernova Remnant

abstract:
  We present X-ray, infrared and radio observations of the field centered on
X-ray source 1E 1547.0-5408 in the Galactic Plane. A new Chandra observation of
this source shows it is unresolved at arc-second resolution, and a new XMM
observation shows that its X-ray spectrum is best described by an absorbed
power-law and blackbody model. A comparison of the X-ray flux observed from
this source between 1980 and 2006 reveals that its absorbed 0.5-10 keV X-ray
flux decreased from ~2x10^-12 ergs cm-2 s-1 to ~3x10^-13 ergs cm-2 during this
period. The most recent XMM observation allows us to put a 5 sigma confidence
upper limit of 14% for the 0.5-10 keV peak-to-peak pulsed fraction. A
near-infrared observation of this field shows a source with magnitude Ks =
15.9+/-0.2 near the position of 1E 1547.0-5408, but the implied X-ray to
infrared flux ratio indicates the infrared emission is from an unrelated field
source, allowing us to limit the IR magnitude of 1E 1547.0-5408 to >17.5.
Archival radio observations reveal that 1E 1547.0-5408 sits at the center of a
faint, small (4' diameter) radio shell, G327.24-0.13, which is possibly a
previously unidentified supernova remnant. The X-ray properties of 1E
1547.0-5408 suggest that this source is a magnetar - a young neutron star whose
X-ray emission is powered by the decay of its extremely strong magnetic field.
The spatial coincidence between this source and G327.24-0.13 suggests that 1E
1547.0-5408 is associated with a young supernova remnant, supporting a neutron
star interpretation. Additional observations are needed to confirm the nature
of both 1E 1547.0-5408 and G327.24-0.13, and to determine if these sources are
associated. If so, this pair will be an important addition to the small number
of known associations between magnetars and supernova remnants.


title:
EC-FORC: A New Cyclic Voltammetry Based Method for Examining Phase
  Transitions and Predicting Equilibrium

abstract:
  We propose a new, cyclic-voltammetry based experimental technique that can
not only differentiate between discontinuous and continuous phase transitions
in an adsorbate layer, but also quite accurately recover equilibrium behavior
from dynamic analysis of systems with a continuous phase transition. The
Electrochemical first-order reversal curve (EC-FORC) diagram for a
discontinuous phase transition (nucleation and growth), such as occurs in
underpotential deposition, is characterized by a negative region, while such a
region does not exist for a continuous phase transition, such as occurs in the
electrosorption of Br on Ag(100). Moreover, for systems with a continuous phase
transition, the minima of the individual EC-FORCs trace the equilibrium curve,
even at very high scan rates. Since obtaining experimental data for the EC-FORC
method would require only a simple reprogramming of the potentiostat used in
conventional cyclic-voltammetry experiments, we believe that this method has
significant potential for easy, rapid, in-situ analysis of systems undergoing
electrochemical deposition.


title: Spontaneous Emission Near Superconducting Bodies

abstract:
  In the present paper we study the spontaneous photon emission due to a
magnetic spin-flip transition of a two-level atom in the vicinity of a
dielectric body like a normal conducting metal or a superconductor. For
temperatures below the transition temperature T_c of a superconductor, the
corresponding spin-flip lifetime is boosted by several orders of magnitude as
compared to the case of a normal conducting body. Numerical results of an exact
formulation are also compared to a previously derived approximative analytical
expression for the spin-flip lifetime and we find an excellent agreement. We
present results on how the spin-flip lifetime depends on the temperature T of a
superconducting body as well as its thickness H. Finally, we study how
non-magnetic impurities as well as possible Eliashberg strong-coupling effects
influence the spin-flip rate. It is found that non-magnetic impurities as well
as strong-coupling effects have no dramatic impact on the spin-flip lifetime.


title: Effective equations for isotropic quantum cosmology including matter

abstract:
  Effective equations often provide powerful tools to develop a systematic
understanding of detailed properties of a quantum system. This is especially
helpful in quantum cosmology where several conceptual and technical
difficulties associated with the full quantum equations can be avoided in this
way. Here, effective equations for Wheeler-DeWitt and loop quantizations of
spatially flat, isotropic cosmological models sourced by a massive or
interacting scalar are derived and studied. The resulting systems are
remarkably different from that given for a free, massless scalar. This has
implications for the coherence of evolving states and the realization of a
bounce in loop quantum cosmology.


title:
Dynamical thermal response functions for strongly correlated
  one-dimensional systems

abstract:
  In this article we study the thermal response functions for two
one-dimensional models, namely the Hubbard and spin-less fermion $t$-$V$
models. By exactly diagonalizing finite sized systems we calculate dynamical
electrical, thermoelectrical, and thermal conductivities via the Kubo
formalism. The thermopower (Seebeck coefficient), Lorenz number, and
dimensionless figure of merit are then constructed which are quantities of
great interest to the physics community both theoretically and experimentally.
We also geometrically frustrate these systems and destroy integrability by the
inclusion of a second neighbor hop. These frustrated systems are shown to have
enhanced thermopower and Lorenz number at intermediate and low temperatures.


title: Search for the decay B+ -> Kbar*0(892) K+

abstract:
  We report on a search for the process B+ -> Kbar*0(892) K+ using 232 10^6
Upsilon(4S) -> BBbar decays collected with the BaBar detector at the PEP-II
asymmetric-energy B Factory at SLAC. From a signal yield of 25 +/- 13 [stat]
+/- 7 [syst] B+ -> Kbar*0(892) (-> K- pi+) K+ events, we place an upper limit
on the branching fraction BF(B+ -> Kbar*0(892) K+) of 1.1 10^-6, at the 90%
confidence level.


title:
Experimental setup for low-energy laser-based angle resolved
  photoemission spectroscopy

abstract:
  A laser-based angle resolved photoemission (APRES) system utilizing 6 eV
photons from the fourth harmonic of a mode-locked Ti:sapphire oscillator is
described. This light source greatly increases the momentum resolution and
photoelectron count rate, while reducing extrinsic background and surface
sensitivity relative to higher energy light sources. In this review, the
optical system is described, and special experimental considerations for
low-energy ARPES are discussed. The calibration of the hemispherical electron
analyzer for good low-energy angle-mode performance is also described. Finally,
data from the heavily studied high T_c superconductor Bi2Sr2CaCu2O8+\delta
(Bi2212) is compared to the results from higher photon energies.


title:
Design, Implementation, and Cooperative Coevolution of an Autonomous/
  Teleoperated Control System for a Serpentine Robotic Manipulator

abstract:
  Design, implementation, and machine learning issues associated with
developing a control system for a serpentine robotic manipulator are explored.
The controller developed provides autonomous control of the serpentine robotic
manipulatorduring operation of the manipulator within an enclosed environment
such as an underground storage tank. The controller algorithms make use of both
low-level joint angle control employing force/position feedback constraints,
and high-level coordinated control of end-effector positioning. This approach
has resulted in both high-level full robotic control and low-level telerobotic
control modes, and provides a high level of dexterity for the operator.


title: Power-law distributions in empirical data

abstract:
  Power-law distributions occur in many situations of scientific interest and
have significant consequences for our understanding of natural and man-made
phenomena. Unfortunately, the detection and characterization of power laws is
complicated by the large fluctuations that occur in the tail of the
distribution -- the part of the distribution representing large but rare events
-- and by the difficulty of identifying the range over which power-law behavior
holds. Commonly used methods for analyzing power-law data, such as
least-squares fitting, can produce substantially inaccurate estimates of
parameters for power-law distributions, and even in cases where such methods
return accurate answers they are still unsatisfactory because they give no
indication of whether the data obey a power law at all. Here we present a
principled statistical framework for discerning and quantifying power-law
behavior in empirical data. Our approach combines maximum-likelihood fitting
methods with goodness-of-fit tests based on the Kolmogorov-Smirnov statistic
and likelihood ratios. We evaluate the effectiveness of the approach with tests
on synthetic data and give critical comparisons to previous approaches. We also
apply the proposed methods to twenty-four real-world data sets from a range of
different disciplines, each of which has been conjectured to follow a power-law
distribution. In some cases we find these conjectures to be consistent with the
data while in others the power law is ruled out.

categories: physics.data-an cond-mat.dis-nn stat.AP stat.ME


title: Small Worlds: Strong Clustering in Wireless Networks

abstract:
  Small-worlds represent efficient communication networks that obey two
distinguishing characteristics: a high clustering coefficient together with a
small characteristic path length. This paper focuses on an interesting paradox,
that removing links in a network can increase the overall clustering
coefficient. Reckful Roaming, as introduced in this paper, is a 2-localized
algorithm that takes advantage of this paradox in order to selectively remove
superfluous links, this way optimizing the clustering coefficient while still
retaining a sufficiently small characteristic path length.


title:
Measurement of Double Helicity Asymmetry in Multi-Particle Production
  with Polarized Proton-Proton Collision at PHENIX

abstract:
  A goal of the PHENIX experiment is to obtain the polarized gluon distribution
function in the proton. Double helicity asymmetry in multi-particle production
with polarized proton-proton collision is measured at midrapidity with RHIC Run
2005 data. This result excludes the maximum positive gluon polarization
("GRSV-max").


title: Tridiagonal pairs of Krawtchouk type

abstract:
  Let $K$ denote an algebraically closed field with characteristic 0 and let
$V$ denote a vector space over $K$ with finite positive dimension. Let $A,A^*$
denote a tridiagonal pair on $V$ with diameter $d$. We say that $A,A^*$ has
Krawtchouk type whenever the sequence $\lbrace d-2i\rbrace_{i=0}^d$ is a
standard ordering of the eigenvalues of $A$ and a standard ordering of the
eigenvalues of $A^*$. Assume $A,A^*$ has Krawtchouk type. We show that there
exists a nondegenerate symmetric bilinear form $< , >$ on $V$ such that
$<Au,v>= < u,Av>$ and $<A^*u,v >= < u,A^*v>$ for $u,v\in V$. We show that the
following tridiagonal pairs are isomorphic: (i) $A,A^*$; (ii) $-A,-A^*$; (iii)
$A^*,A$; (iv) $-A^*,-A$. We give a number of related results and conjectures.


title:
Applying Test-Paradigms in a Generic Tutoring System Concept for
  Web-based Learning

abstract:
  Realizing test scenarios through a tutoring system involve questions about
architecture and didactic methods in such a system. Observing the fact that
traditional tutoring systems normally are domain-static, this paper shows
investigations for a generic domain-independent tutoring system for utilizing
test scenarios in computer-based and web-based environments. Furthermore, test
paradigms are analyzed and it is presented an approach for realizing
functionality for applying test paradigms in the presented generic tutoring
system architecture by an XML-specified language.


title:
Stability and mode analysis of solar coronal loops using thermodynamic
  irreversible energy principles

abstract:
  We study the modes and stability of non - isothermal coronal loop models with
different intensity values of the equilibrium magnetic field. We use an energy
principle obtained via non - equilibrium thermodynamic arguments. The principle
is expressed in terms of Hermitian operators and allow to consider together the
coupled system of equations: the balance of energy equation and the equation of
motion. We determine modes characterized as long - wavelength disturbances that
are present in inhomogeneous media. This character of the system introduces
additional difficulties for the stability analysis because the inhomogeneous
nature of the medium determines the structure of the disturbance, which is no
longer sinusoidal. Moreover, another complication is that we obtain a
continuous spectrum of stable modes in addition to the discrete one. We obtain
a unique unstable mode with a characteristic time that is comparable with the
characteristic life-time observed for loops. The feasibility of wave-based and
flow-based models is examined.


title: Rota-Baxter Categories

abstract:
  We introduce Rota-Baxter categories and construct examples of such
structures.


title:
Meta-nematic transitions in a bilayer system: Application to the bilayer
  ruthenate

abstract:
  It was suggested that the two consecutive metamagnetic transitions and the
large residual resistivity discovered in Sr$_3$Ru$_2$O$_7$ can be understood
via the nematic order and its domains in a single layer system. However, a
recently reported anisotropy between two longitudinal resistivities induced by
tilting the magnetic field away from the c-axis cannot be explained within the
single layer nematic picture. To fill the gap in our understanding within the
nematic order scenario, we investigate the effects of bilayer coupling and
in-plane magnetic field on the electronic nematic phases in a bilayer system.
We propose that the in-plane magnetic field in the bilayer system modifies the
energetics of the domain formation, since it breaks the degeneracy of two
different nematic orientations. Thus the system reveals a pure nematic phase
with a resistivity anisotropy in the presence of an in-plane magnetic field. In
addition to the nematic phase, the bilayer coupling opens a novel route to a
hidden nematic phase that preserves the x-y symmetry of the Fermi surfaces.


title:
A multi-wavelength study of z = 3.15 Lyman-alpha emitters in the GOODS
  South Field

abstract:
  Context: Ly-alpha-emitters have proven to be excellent probes of faint,
star-forming galaxies in the high redshift universe. However, although the
sample of known emitters is increasingly growing, their nature (e.g. stellar
masses, ages, metallicities, star-formation rates) is still poorly constrained.
  Aims: We aim to study the nature of Ly-alpha-emitters, to find the properties
of a typical Ly-alpha-emitting galaxy and to compare these properties with the
properties of other galaxies at similar redshift, in particular Lyman-break
galaxies.
  Methods: We have performed narrow-band imaging at the VLT, focused on
Ly-alpha at redshift z ~ 3.15, in the GOODS-S field. We have identified a
sample of Ly-alpha-emitting candidates, and we have studied their Spectral
Energy Distributions (SEDs).
  Results: We find that the emitters are best fit by an SED with low
metallicity (Z/Z_sun = 0.005), low dust extinction (A_V ~ 0.32) and medium
stellar masses of approximately 10^9 M_sun. The age is not very well
constrained. One object out of 24 appears to be a high redshift
Ly-alpha-emitting dusty starburst galaxy. We find filamentary structure as
traced by the Ly-alpha-emitters at the 4 sigma level. The rest-frame UV SED of
these galaxies is very similar to that of Lyman Break Galaxies (LBGs) and
comply with the selection criteria for U-band drop-outs, except they are
intrinsically fainter than the current limit for LBGs.
  Conclusion: Ly-alpha-emitters are excellent probes of galaxies in the distant
universe, and represent a class of star-forming, dust and AGN free, medium mass
objects.


title:
Anisotropic Magnification Distortion of the 3D Galaxy Correlation: I.
  Real Space

abstract:
  It is well known gravitational lensing, mainly via magnification bias,
modifies the observed galaxy/quasar clustering. Such discussions have largely
focused on the 2D angular correlation. Here and in a companion paper (Paper II)
we explore how magnification bias distorts the 3D correlation function and
power spectrum, as first considered by Matsubara. The interesting point is: the
distortion is anisotropic. Magnification bias preferentially enhances the
observed correlation in the line-of-sight (LOS) orientation, especially on
large scales. For example at LOS separation of ~100 Mpc/h, where the intrinsic
galaxy-galaxy correlation is rather weak, the observed correlation can be
enhanced by lensing by a factor of a few, even at a modest redshift of z ~
0.35. The opportunity: this lensing anisotropy is distinctive, making it
possible to separately measure the galaxy-galaxy, galaxy-magnification and
magnification-magnification correlations, without measuring galaxy shapes. The
anisotropy is distinguishable from the well known distortion due to peculiar
motions, as will be discussed in Paper II. The challenge: the magnification
distortion of the galaxy correlation must be accounted for in interpreting data
as precision improves. For instance, the ~100 Mpc/h baryon acoustic oscillation
scale in the correlation function is shifted by up to ~3% in the LOS
orientation, and up to ~0.6% in the monopole, depending on the galaxy bias,
redshift and number count slope. The corresponding shifts in the inferred
Hubble parameter and angular diameter distance, if ignored, could significantly
bias measurements of the dark energy equation of state. Lastly, magnification
distortion offers a plausible explanation for the well known excess
correlations seen in pencil beam surveys.


title:
Index reduction for Brauer classes via stable sheaves (with an appendix
  by Bhargav Bhatt)

abstract:
  We use twisted sheaves to study the problem of index reduction for Brauer
classes. In general terms, this problem may be phrased as follows: given a
field $k$, a $k$-variety $X$, and a class $\alpha \in \Br(k)$, compute the
index of the class $\alpha_{k(X)} \in \Br(X)$ obtained from $\alpha$ by
extension of scalars to $k(X)$. We give a general method for computing index
reduction which refines classical results of Schofield and van den Bergh. When
$X$ is a curve of genus 1, we use Atiyah's theorem on the structure of stable
vector bundles with integral slope to show that our formula simplifies
dramatically, giving a complete solution to the index reduction problem in this
case. Using the twisted Fourier-Mukai transform, we show that a similarly
simple formula describes homogeneous index reduction on torsors under
higher-dimensional abelian varieties.


title: The Merger in Abell 576: A Line of Sight Bullet Cluster?

abstract:
  Using a combination of Chandra and XMM observations, we confirmed the
presence of a significant velocity gradient along the NE/E-W/SW direction in
the intracluster gas of the cluster Abell 576. The results are consistent with
a previous ASCA SIS analysis of this cluster. The error weighted average over
ACIS-S3, EPIC MOS 1 & 2 spectrometers for the maximum velocity difference is
>3.3E03 km/s at the 90% confidence level, similar to the velocity limits
estimated indirectly for the "bullet" cluster (1E0657-56). The probability that
the velocity gradient is generated by standard random gain fluctuations with
Chandra and XMM is <0.1%. The regions of maximum velocity gradient are in CCD
zones that have the lowest temporal gain variations. It is unlikely that the
velocity gradient is due to Hubble distance differences between projected
clusters (probability<~0.01%). We mapped the distribution of elemental
abundance ratios across the cluster and detected a strong chemical
discontinuity using the abundance ratio of silicon to iron, equivalent to a
variation from 100% SN Ia iron mass fraction in the West-Northwest regions to
32% in the Eastern region. The "center" of the cluster is located at the
chemical discontinuity boundary, which is inconsistent with the radially
symmetric chemical gradient found in some regular clusters, but consistent with
a cluster merging scenario. We predict that the velocity gradient as measured
will produce a variation of the CMB temperature towards the East of the core of
the cluster that will be detectable by current and near-future bolometers. The
measured velocity gradient opens for the possibility that this cluster is
passing through a near line-of-sight merger stage where the cores have recently
crossed.


title:
The Abundances of Light Neutron-Capture Elements in Planetary Nebulae
  II. s-process Enrichments and Interpretation

abstract:
  We present the results of a large-scale survey of neutron(n)-capture elements
in Galactic planetary nebulae (PNe), undertaken to study enrichments from
s-process nucleosynthesis in their progenitor stars. From new K band
observations of over 100 PNe supplemented by data from the literature, we have
detected the emission lines [Kr III] 2.199 and/or [Se IV] 2.287 $\mu$m in 81 of
120 objects. We determine Se and Kr elemental abundances, employing ionization
correction formulae derived in the first paper of this series. We find a
significant range in Se and Kr abundances, from near solar (no enrichment) to
enhanced by >1.0 dex relative to solar, which we interpret as self-enrichment
due to in situ s-process nucleosynthesis. Kr tends to be more strongly enriched
than Se; in 18 objects exhibiting both Se and Kr emission, we find that [Kr/Se]
= 0.5$\pm$0.2.
  Our survey has increased the number of PNe with n-capture element abundance
determinations by a factor of ten, enabling us for the first time to search for
correlations with other nebular properties. As expected, we find a positive
correlation between s-process enrichments and the C/O ratio. Type I and bipolar
PNe, which arise from intermediate-mass progenitors (>3-4 solar masses),
exhibit little to no s-process enrichments. Finally, PNe with H-deficient
Wolf-Rayet central stars do not exhibit systematically larger s-process
enrichments than objects with H-rich nuclei. Overall, 44% of the PNe in our
sample display significant s-process enrichments (>0.3 dex). Using an empirical
PN luminosity function to correct for incompleteness, we estimate that the true
fraction of s-process enriched Galactic PNe is at least 20%.


title:
Voltage Induced Hidden Symmetry and Photon Entanglement Generation in a
  Single, Site-Selected Quantum Dot

abstract:
  Present proposals for the realisation of entangled photon pair sources using
the radiative decay of the biexciton in semiconductor quantum dots are limited
by the need to enforce degeneracy of the two intermediate, single exciton
states. We show how this requirement is lifted if the biexciton binding energy
can be tuned to zero and we demonstrate this unbinding of the biexciton in a
single, pre-positioned InAs quantum dot subject to a lateral electric field.
Full Configuration-Interaction calculations are presented that reveal how the
biexciton is unbound through manipulation of the electron-hole Coulomb
interaction and the consequent introduction of Hidden Symmetry.


title:
Clustering Properties of restframe UV selected galaxies II: Migration of
  Star Formation sites with cosmic time from GALEX and CFHTLS

abstract:
  We analyze the clustering properties of ultraviolet selected galaxies by
using GALEX-SDSS data at z<0.6 and CFHTLS deep u' imaging at z=1. These
datasets provide a unique basis at z< 1 which can be directly compared with
high redshift samples built with similar selection criteria. We discuss the
dependence of the correlation function parameters (r0, delta) on the
ultraviolet luminosity as well as the linear bias evolution. We find that the
bias parameter shows a gradual decline from high (b > 2) to low redshift (b ~
0.79^{+0.1}_{-0.08}). When accounting for the fraction of the star formation
activity enclosed in the different samples, our results suggest that the bulk
of star formation migrated from high mass dark matter halos at z>2 (10^12 <
M_min < 10^13 M_sun, located in high density regions), to less massive halos at
low redshift (M_min < 10^12 M_sun, located in low density regions). This result
extends the ``downsizing'' picture (shift of the star formation activity from
high stellar mass systems at high z to low stellar mass at low z) to the dark
matter distribution.


title: Regularity of Dirichlet nearly minimizing multiple-valued functions

abstract:
  In this paper, we extend the related notions of Dirichlet quasiminimizer,
$\omega-$minimizer and almost minimizer to the framework of multiple-valued
functions in the sense of Almgren and prove Holder regularity results. We also
give examples of those minimizers with various branch sets.


title:
Strain localization in a shear transformation zone model for amorphous
  solids

abstract:
  We model a sheared disordered solid using the theory of Shear Transformation
Zones (STZs). In this mean-field continuum model the density of zones is
governed by an effective temperature that approaches a steady state value as
energy is dissipated. We compare the STZ model to simulations by Shi, et
al.(Phys. Rev. Lett. 98 185505 2007), finding that the model generates
solutions that fit the data,exhibit strain localization, and capture important
features of the localization process. We show that perturbations to the
effective temperature grow due to an instability in the transient dynamics, but
unstable systems do not always develop shear bands. Nonlinear energy
dissipation processes interact with perturbation growth to determine whether a
material exhibits strain localization. By estimating the effects of these
interactions, we derive a criterion that determines which materials exhibit
shear bands based on the initial conditions alone. We also show that the shear
band width is not set by an inherent diffusion length scale but instead by a
dynamical scale that depends on the imposed strain rate.


title: Co-orbital Oligarchy

abstract:
  We present a systematic examination of the changes in semi-major axis caused
by the mutual interactions of a group of massive bodies orbiting a central star
in the presence of eccentricity dissipation. For parameters relevant to the
oligarchic stage of planet formation, dynamical friction keeps the typical
eccentricities small and prevents orbit crossing. Interactions at impact
parameters greater than several Hill radii cause the protoplanets to repel each
other; if the impact parameter is instead much less than the Hill radius, the
protoplanets shift slightly in semi-major axis but remain otherwise
unperturbed. If the orbits of two or more protoplanets are separated by less
than a Hill radius, they are each pushed towards an equilibrium spacing between
their neighbors and can exist as a stable co-orbital system. In the
shear-dominated oligarchic phase of planet formation we show that the feeding
zones contain several oligarchs instead of only one. Growth of the protoplanets
in the oligarchic phase drives the disk to an equilibrium configuration that
depends on the mass ratio of protoplanets to planetesimals, $\Sigma/\sigma$.
Early in the oligarchic phase, when $\Sigma/\sigma$ is low, the spacing between
rows of co-orbital oligarchs are about 5 Hill radii wide, rather than the 10
Hill radii cited in the literature. It is likely that at the end of oligarchy
the average number of co-orbital oligarchs is greater than unity. In the outer
solar system this raises the disk mass required to form the ice giants. In the
inner solar system this lowers the mass of the final oligarchs and requires
more giant impacts than previously estimated. This result provides additional
evidence that Mars is not an untouched leftover from the oligarchic phase, but
must be composed of several oligarchs assembled through giant impacts.


title:
WACA: A Hierarchical Weighted Clustering Algorithm optimized for Mobile
  Hybrid Networks

abstract:
  Clustering techniques create hierarchal network structures, called clusters,
on an otherwise flat network. In a dynamic environment-in terms of node
mobility as well as in terms of steadily changing device parameters-the
clusterhead election process has to be re-invoked according to a suitable
update policy. Cluster re-organization causes additional message exchanges and
computational complexity and it execution has to be optimized. Our
investigations focus on the problem of minimizing clusterhead re-elections by
considering stability criteria. These criteria are based on topological
characteristics as well as on device parameters. This paper presents a weighted
clustering algorithm optimized to avoid needless clusterhead re-elections for
stable clusters in mobile ad-hoc networks. The proposed localized algorithm
deals with mobility, but does not require geographical, speed or distances
information.


title: The limiting behavior of the Liu-Yau quasi-local energy

abstract:
  The small- and large-sphere limits of the quasi-local energy recently
proposed by Liu and Yau are carefully examined. It is shown that in the
small-sphere limit, the non-vacuum limit of the Liu-Yau quasi-local energy
approaches the expected value \frac{4\pi}{3} r^3 T(e_0, e_0)$. Here, T is the
energy-stress tensor of matter, e_0 \in T_p M is unit time-like and
future-directed at the point p located at the center of the small sphere of
radius $r$ in the limit r \to 0. In vacuum, however, the limiting value of the
Liu-Yau quasi-local energy contains the desired limit \frac{r^5}{90} B(e_0,
e_0, e_0, e_0), where B is the Bel-Robinson tensor, as well as an extra term.
In the large-sphere limit at null infinity, for isolated gravitational sources,
the Liu-Yau quasi-local energy is shown to recover the Bondi mass and Bondi
news flux, in space-times that are asymptotically empty and flat at null
infinity. The physical validity of the Liu-Yau model in view of these results
is discussed.


title: Analytic result for the one-loop massless triangle Feynman diagram

abstract:
  Different mathematical methods have been applied to obtain the analytic
result for the massless triangle Feynman diagram yielding a sum of four
linearly independent hypergeometric functions $F_4$. In this paper I work out
the diagram and show that that result, though mathematically sound, is not
physically correct, because it misses a fundamental physical constraint imposed
by the conservation of momentum, which should reduce by one the total number of
linearly independent (l.i.) functions $F_4$ in the overall solution. Taking
into account that the momenta flowing along the three legs of the diagram are
constrained by momentum conservation, the number of overall l.i. functions that
enter the most general solution must reduce accordingly.
  To determine the exact structure and content of the analytic solution for the
three-point function, I use the analogy that exists between Feynman diagrams
and electric circuit networks, in which the electric current flowing in the
network plays the role of the momentum flowing in the lines of a Feynman
diagram. This analogy is employed to define exactly which three out of the four
hypergeometric functions are relevant to the analytic solution for the Feynman
diagram. The analogy is built based on the equivalence between electric
resistance circuit networks of type "Y" and "Delta" in which flows a conserved
current. The equivalence is established via the theorem of minimum energy
dissipation within circuits having these structures.


title: An X-ray Spectral Analysis of the Central Regions of NGC 4593

abstract:
  We present a detailed analysis of XMM-Newton EPIC-pn data for the Seyfert-1
galaxy NGC 4593. We discuss the X-ray spectral properties of this source as
well as its variations with time. The 0.5-10 keV spectrum shows significant
complexity beyond a simple power-law form, with clear evidence existing for a
"soft excess" as well as absorption by highly ionized plasma (a warm absorber)
within the central engine of this active galactic nucleus. We show that the
soft excess is best described as originating from thermal Comptonization by
plasma that is appreciably cooler than the primary X-ray emitting plasma; we
find that the form of the soft excess cannot be reproduced adequately by
reflection from an ionized accretion disk. The only measurable deviation from
the power-law continuum in the hard spectrum comes from the presence of cold
and ionized fluorescent iron-K emission lines at 6.4 and 6.97 keV,
respectively. While constraints on the ionized iron line are weak, the cold
line is found to be narrow at CCD-resolution with a flux that does not track
the temporal changes in the underlying continuum, implying an origin in the
outer radii of the accretion disk or the putative molecular torus of Seyfert
unification schemes. The X-ray continuum itself varies on all accessible time
scales. We detect a ~230-second time-lag between soft and hard EPIC-pn bands
that, if interpreted as scattering timescales within a Comptonizing disk
corona, can be used to constrain the physical size of the primary X-ray source
to a characteristic length scale of ~2 gravitational radii. Taken together, the
small implied coronal size and the large implied iron line emitting region
indicate a departure from the current picture of a "typical" AGN geometry.


title: Sublinear Algorithms for Approximating String Compressibility

abstract:
  We raise the question of approximating the compressibility of a string with
respect to a fixed compression scheme, in sublinear time. We study this
question in detail for two popular lossless compression schemes: run-length
encoding (RLE) and Lempel-Ziv (LZ), and present sublinear algorithms for
approximating compressibility with respect to both schemes. We also give
several lower bounds that show that our algorithms for both schemes cannot be
improved significantly.
  Our investigation of LZ yields results whose interest goes beyond the initial
questions we set out to study. In particular, we prove combinatorial structural
lemmas that relate the compressibility of a string with respect to Lempel-Ziv
to the number of distinct short substrings contained in it. In addition, we
show that approximating the compressibility with respect to LZ is related to
approximating the support size of a distribution.


title:
Challenging Lorentz noninvariant neutrino oscillations without neutrino
  masses

abstract:
  We show that the combined data from solar, long-baseline and reactor neutrino
experiments can exclude the generalized bicycle model of Lorentz noninvariant
direction-dependent and/or direction-independent oscillations of massless
neutrinos. This model has five parameters, which is more than is needed in
standard oscillation phenomenology with neutrino masses. Solar data alone are
sufficient to exclude the pure direction-dependent case. The combination of
solar and long-baseline data rules out the pure direction-independent case.
With the addition of KamLAND data, a mixture of direction-dependent and
direction-independent terms in the effective Hamiltonian is also excluded.


title: Supernova Classes and Subclasses

abstract:
  The discovery of many objects with unprecedented, amazing observational
characteristics caused the last decade to be the most prolific period for the
supernova research. Many of these new supernovae are transitional objects
between existing classes, others well enter within the defined classes, but
still show unique properties. This makes the traditional classification scheme
inadequate to take into account the overall SN variety and, consequently,
requires the introduction of new subclasses.


title: On Anomalies in Annotation Systems

abstract:
  Today's computer-based annotation systems implement a wide range of
functionalities that often go beyond those available in traditional
paper-and-pencil annotations. Conceptually, annotation systems are based on
thoroughly investigated psycho-sociological and pedagogical learning theories.
They offer a huge diversity of annotation types that can be placed in textual
as well as in multimedia format. Additionally, annotations can be published or
shared with a group of interested parties via well-organized repositories.
Although highly sophisticated annotation systems exist both conceptually as
well as technologically, we still observe that their acceptance is somewhat
limited. In this paper, we argue that nowadays annotation systems suffer from
several fundamental problems that are inherent in the traditional
paper-and-pencil annotation paradigm. As a solution, we propose to shift the
annotation paradigm for the implementation of annotation system.


title: G-convergence and homogenization of viscoelastic flows

abstract:
  The paper is devoted to homogenization of two-phase incompressible
viscoelastic flows with disordered microstructure. We study two cases. In the
first case, both phases are modeled as Kelvin-Voight viscoelastic materials. In
the second case, one phase is a Kelvin-Voight material, and the other is a
viscous Newtonian fluid. The microscale system contains the conservation of
mass and balance of momentum equations. The inertial terms in the momentum
equation incorporate the actual interface advected by the flow. In the
constitutive equations, a frozen interface is employed. The interface geometry
is arbitrary: we do not assume periodicity, statistical homogeneity or scale
separation. The problem is homogenized using G-convergence and oscillating test
functions. Since the microscale system is not parabolic, previously known
constructions of the test functions do not work here. The test functions
developed in the paper are non-local in time and satisfy divergence-free
constraint exactly. The latter feature enables us to avoid working with
pressure directly. We show that the effective medium is a single phase
viscoelastic material that is not necessarily of Kelvin-Voight type. The
effective constitutive equation contains a long memory viscoelastic term, as
well as instantaneous elastic and viscous terms.


title:
Geochemistry of U and Th and its Influence on the Origin and Evolution
  of the Crust of Earth and the Biological Evolution

abstract:
  We have investigated the migration behaviors of uranium (U) and thorium (Th)
in Earth and other terrestrial planets. Theoretical models of U and Th
migration have been proposed. These models suggest that the unique features of
Earth are closely connected with its unique U and Th migration models and
distribution patterns. In the Earth, U and Th can combine with oxidative
volatile components and water, migrate up to the asthenosphere position to form
an enrichment zone (EZ) of U and Th first, and then migrate up further to the
crusts through magmatism and metamorphism. We emphasize that the formation of
an EZ of U, Th and other heat-producing elements is a prerequisite for the
formation of a plate tectonic system. The heat-producing elements, currently
mainly U and Th, in the EZ are also the energy sources that drive the formation
and evolution of the crust of Earth and create special granitic continental
crusts. In other terrestrial planets, including Mercury, Venus, and Mars, an EZ
can not be formed because of a lack of oxidative volatile components and water.
For this reason, a plate tectonic system can not been developed in these
planets. We also emphasize the influence of U and Th in EZ on the development
and evolution of life on Earth. We propose that since the Earth and planets
were born in a united solar system, there should be some common mechanisms to
create the similarities and differences between them. We have tried to develop
an integrated view to explain some problems in the tectonics of Earth and
evolution, bio-evolution, and planetary dynamics through U and Th geochemistry.
We believe that a comprehensive exploration on energy sources and their
evolution is a good way to build bridges between different disciplines of
science in order to better understand the Earth and planets.


title: Effective Hamiltonian Theory and Its Applications in Quantum Information

abstract:
  This paper presents a useful compact formula for deriving an effective
Hamiltonian describing the time-averaged dynamics of detuned quantum systems.
The formalism also works for ensemble-averaged dynamics of stochastic systems.
To illustrate the technique we give examples involving Raman processes,
Bloch-Siegert shifts and Quantum Logic Gates.


title: Some extremal problems related to Bell-type inequalities

abstract:
  The best approximation by bounded product functions is calculated for some
very simple two-valued functions of two variables.


title:
Generalizations of Khovanskii's theorems on growth of sumsets in abelian
  semigroups

abstract:
  We show that if $P$ is a lattice polytope in the nonnegative orthant of
$\R^k$ and $\chi$ is a coloring of the lattice points in the orthant such that
the color $\chi(a+b)$ depends only on the colors $\chi(a)$ and $\chi(b)$, then
the number of colors of the lattice points in the dilation $nP$ of $P$ is for
large $n$ given by a polynomial (or, for rational $P$, by a quasipolynomial).
This unifies a classical result of Ehrhart and Macdonald on lattice points in
polytopes and a result of Khovanski\u\i{} on sumsets in semigroups. We also
prove a strengthening of multivariate generalizations of Khovanski\u\i's
theorem. Another result of Khovanski\u\i{} states that the size of the image of
a finite set after $n$ applications of mappings from a finite family of
mutually commuting mappings is for large $n$ a polynomial. We give a
combinatorial proof of a multivariate generalization of this theorem.


title:
Cellular automata for traffic flow simulation with safety embedded
  notions

abstract:
  In this paper a cellular automata model for one-lane traffic flow is
presented. A new set of rules is proposed to better capture driver reactions to
traffic that are intended to preserve safety on the highway. As a result,
drivers behavior is derived from an analysis that determines the most
appropriate action for a vehicle based on the distance from the vehicle ahead
of it and the velocities of the two neighbor vehicles. The model preserves
simplicity of CA rules and at the same time makes the results closer to real
highway behavior. Simulation results exhibit the three states observed in real
traffic flow: Free-flow states, synchronized states, and stop-and-go states.


title:
Flame Evolution During Type Ia Supernovae and the Deflagration Phase in
  the Gravitationally Confined Detonation Scenario

abstract:
  We develop an improved method for tracking the nuclear flame during the
deflagration phase of a Type Ia supernova, and apply it to study the variation
in outcomes expected from the gravitationally confined detonation (GCD)
paradigm. A simplified 3-stage burning model and a non-static ash state are
integrated with an artificially thickened advection-diffusion-reaction (ADR)
flame front in order to provide an accurate but highly efficient representation
of the energy release and electron capture in and after the unresolvable flame.
We demonstrate that both our ADR and energy release methods do not generate
significant acoustic noise, as has been a problem with previous ADR-based
schemes. We proceed to model aspects of the deflagration, particularly the role
of buoyancy of the hot ash, and find that our methods are reasonably
well-behaved with respect to numerical resolution. We show that if a detonation
occurs in material swept up by the material ejected by the first rising bubble
but gravitationally confined to the white dwarf (WD) surface (the GCD
paradigm), the density structure of the WD at detonation is systematically
correlated with the distance of the deflagration ignition point from the center
of the star. Coupled to a suitably stochastic ignition process, this
correlation may provide a plausible explanation for the variety of nickel
masses seen in Type Ia Supernovae.


title: Noncommutative Fluids

abstract:
  We review the connection between noncommutative gauge theory, matrix models
and fluid mechanical systems. The noncommutative Chern-Simons description of
the quantum Hall effect and bosonization of collective fermion states are used
as specific examples.

categories: hep-th cond-mat.mes-hall math-ph math.MP physics.flu-dyn


title:
Inquiring the Potential of Evoking Small-World Properties for
  Self-Organizing Communication Networks

abstract:
  Mobile multi-hop ad hoc networks allow establishing local groups of
communicating devices in a self-organizing way. However, in a global setting
such networks fail to work properly due to network partitioning. Providing that
devices are capable of communicating both locally-e.g. using Wi-Fi or
Bluetooth-and additionally also with arbitrary remote devices-e.g. using
GSM/UMTS links-the objective is to find efficient ways of inter-linking
multiple network partitions. Tackling this problem of topology control, we
focus on the class of small-world networks that obey two distinguishing
characteristics: they have a strong local clustering while still retaining a
small average distance between two nodes. This paper reports on results gained
investigating the question if small-world properties are indicative for an
efficient link management in multiple multi-hop ad hoc network partitions.


title:
Computational techniques for proving identities in symmetric
  compositions

abstract:
  We present in this work a complete session in a Mathematica notebook. The aim
of this notebook is to check identities in symmetric compositions. This
notebook is a complement of our work [1] and it has all the explicit
computations. We refer the reader to that paper which can be seen in
http://www.uibk.ac.at/mathematik/loos/jordan/index.html. First of all we will
present a few number of comands in order to simplify identities by extracting
scalars, SOut. The rest of the strategy holds on the powerfull of using
patterns and rules.


title:
Characterization of the matrix whose norm is determined by its action on
  decreasing sequences

abstract:
  Let $A=(a_{j,k})_{j,k \ge 1}$ be a non-negative matrix. In this paper, we
characterize those $A$ for which $\|A\|_{E, F}$ are determined by their actions
on decreasing sequences, where $E$ and $F$ are suitable normed Riesz spaces of
sequences.


title: A slight improvement to Korenblum's constant

abstract:
  Let $A^2(D)$ be the Bergman space over the open unit disk $D$ in the complex
plane. Korenblum conjectured that there is an absolute constant $c \in (0,1)$
such that whenever $|f(z)|\le |g(z)|$ in the annulus $c<|z|<1$ then $||f(z)||
\le ||g(z)||$.In 2004 C.Wang gave an upper bound on $c$,that is, $c < 0.67795$,
and in 2006 A.Schuster gave a lower bound ,$c > 0.21 $ .In this paper we
slightly improve the upper bound for $c$.


title:
SUSY R-parity violating contributions to the width differences for
  $D-\bar{D}$ and $B_{d,s}-\bar B_{d,s}$ systems

abstract:
  We study R-parity violating contributions to the mixing parameter $y$ for
$D^0 -\bar D^0$ and $B^0_{d,s} - \bar B^0_{d,s}$ systems. We first obtain
general expressions for new physics contributions to $y$ from effective four
fermion operators. We then use them to study R-parity contributions. We find
that R-parity violating contributions to $D^0 - \bar D^0$ mixing, and $B_{d}^0
- \bar B_{d}^0$ to be small. There may be sizable contribution to $B_s^0 -\bar
B_s^0$ mixing. We also obtain some interesting bounds on R-parity violating
parameters using known Standard Model predictions and experimental data.


title: The absolutely continuous spectrum of Jacobi matrices

abstract:
  I explore some consequences of a groundbreaking result of Breimesser and
Pearson on the absolutely continuous spectrum of one-dimensional Schr"odinger
operators. These include an Oracle Theorem that predicts the potential and
rather general results on the approach to certain limit potentials. In
particular, we prove a Denisov-Rakhmanov type theorem for the general finite
gap case.
  The main theme is the following: It is extremely difficult to produce
absolutely continuous spectrum in one space dimension and thus its existence
has strong implications.


title:
Influence of Hydrodynamic Interactions on Mechanical Unfolding of
  Proteins

abstract:
  We incorporate hydrodynamic interactions in a structure-based model of
ubiquitin and demonstrate that the hydrodynamic coupling may reduce the peak
force when stretching the protein at constant speed, especially at larger
speeds. Hydrodynamic interactions are also shown to facilitate unfolding at
constant force and inhibit stretching by fluid flows.


title: On the threshold for k-regular subgraphs of random graphs

abstract:
  The $k$-core of a graph is the largest subgraph of minimum degree at least
$k$. We show that for $k$ sufficiently large, the $(k + 2)$-core of a random
graph $\G(n,p)$ asymptotically almost surely has a spanning $k$-regular
subgraph. Thus the threshold for the appearance of a $k$-regular subgraph of a
random graph is at most the threshold for the $(k+2)$-core. In particular, this
pins down the point of appearance of a $k$-regular subgraph in $\G(n,p)$ to a
window for $p$ of width roughly $2/n$ for large $n$ and moderately large $k$.


title: Emergence of Fluctuations from a Tachyonic Big Bang

abstract:
  It has recently been speculated that the end state of a collapsing universe
is a tachyonic big crunch. The time reversal of this process would be the
emergence of an expanding universe from a tachyonic big bang. In this
framework, we study the emergence of cosmological fluctuations. In particular,
we compare the amplitude of the perturbations at tne end of the tachyon phase
with what would be obtained assuming the usual vacuum initial conditions. We
find that cosmological fluctuations emerge in a thermal state. We comment on
the relation to the trans-Planckian problem of inflationary cosmology.


title: Hybrid Performance of the Pierre Auger Observatory

abstract:
  A key feature of the Pierre Auger Observatory is its hybrid design, in which
ultra high energy cosmic rays are detected simultaneously by fluorescence
telescopes and a ground array. The two techniques see air showers in
complementary ways, providing important cross-checks and measurement
redundancy. Much of the hybrid capability stems from the accurate geometrical
reconstruction it achieves, with accuracy better than either the ground array
detectors or a single telescope could achieve independently. We have studied
the geometrical and longitudinal profile reconstructions of hybrid events. We
present the results for the hybrid performance of the Observatory, including
trigger efficiency, energy and angular resolution, and the efficiency of the
event selection.


title:
Toward Application of a Thick Gas Electron Multiplier (THGEM) Readout
  for a Dark Matter Detector

abstract:
  The Yale-Weizmann collaboration aims to develop a low-radioactivity
(low-background) cryogenic noble liquid detector for Dark-Matter (DM) search in
measurements to be performed deep underground as for example carried out by the
XENON collaboration. A major issue is the background induced by natural
radioactivity of present-detector components including the Photo Multiplier
Tubes (PMT) made from glass with large U-Th content. We propose to use advanced
Thick Gaseous Electron Multipliers (THGEM) recently developed at the Weizmann
Institute of Science (WIS). These "hole-multipliers" will measure in a
two-phase (liquid/gas) Xe detector electrons extracted into the gas phase from
both ionization in the liquid as well as scintillation-induced photoelectrons
from a CsI photocathode immersed in LXe. We report on initial tests (in gas) of
THGEM made out of Cirlex (Kapton) which is well known to have low Ra-Th content
instead of the usual G10 material with high Ra-Th content.


title:
Orbital magnetization and its effect in antiferromagnets on the
  distorted fcc lattice

abstract:
  We study the intrinsic orbital magnetization (OM) in antiferromagnets on the
distorted face-centered-cubic lattice. The combined lattice distortion and spin
frustration induce nontrivial $k$-space Chern invariant, which turns to result
in profound effects on the OM properties. We derive a specific relation between
the OM and the Hall conductivity, according to which it is found that the
intrinsic OM vanishes when the electron chemical potential lies in the Mott
gap. The distinct behavior of the intrinsic OM in the metallic and insulating
regions is shown. The Berry phase effects on the thermoelectric transport is
also discussed.


title:
Reply to `Comment on ``Helmholtz Theorem and the V-Gauge in the Problem
  of Superluminal and Instantaneous Signals in Classical Electrodynamics" by A.
  Chubykalo Et Al' by J. A. Heras [FOUND. Phys. Lett. vol. 19(6) p. 579 (2006)]

abstract:
  This is the reply to `COMMENT ON ``HELMHOLTZ THEOREM AND THE V-GAUGE IN THE
PROBLEM OF SUPERLUMINAL AND INSTANTANEOUS SIGNALS IN CLASSICAL ELECTRODYNAMICS"
BY A. CHUBYKALO ET AL' BY J. A. HERAS [FOUND. PHYS. LETT. vol. 19(6) p. 579
(2006)]


title: Discovering the Kerr and Kerr-Schild metrics

abstract:
  An historical account of the reasoning that led to the discovery of the Kerr
and Kerr-Schild metrics in 1963-1964, and their physical interpretation as
rotating black holes, is presented.


title:
Calculation of the Underground Muon Intensity Crouch Curve from a
  Parameterization of the Flux at Surface

abstract:
  Utilizing only the vertical muon intensity of the Gaisser parameterization of
the muon flux at the surface and propagating this energy spectrum underground
according to statistical ionization and radiative energy losses, it is possible
to calculate the underground muon intensity Crouch curve. In addition, the
primary spectral index of the Gaisser parameterization can be adjusted from
$E^{-2.7}$ to $E^{-2.643}$ simply by minimizing the deviation from the Crouch
curve. For chemical compositions other than standard rock, the propagation of
the spectrum underground can be repeated with a different muon energy loss in
the material. The resulting underground muon intensity curve represents a
consistent conversion of the Crouch curve to the local rock, fully accounting
for the energy dependence of the muon $dE/dx$.


title:
Cosmological Black Hole Formation due to QCD and Electroweak Phase
  Transitions

abstract:
  We solve dynamical equations of motion to determine the conditions under
which an over-dense region in the early universe will lead to collapse to a
black hole, starting from horizon crossing of the over-dense region to the
point of gravitational instability. Here we focus on the sensitivity to QCD and
electroweak phase transitions. We then solve rate equations to determine the
mass distribution of black holes in the present universe. A second order phase
transition or rapid crossover would have significant consequences only if the
index of primordial density fluctuations n > 1.25. However, a first order
transition would lead to a black hole dominated universe for any realistic
value of n including n=1.


title: The theory of optical dispersive shock waves in photorefractive media

abstract:
  The theory of optical dispersive shocks generated in propagation of light
beams through photorefractive media is developed. Full one-dimensional
analytical theory based on the Whitham modulation approach is given for the
simplest case of sharp step-like initial discontinuity in a beam with
one-dimensional strip-like geometry. This approach is confirmed by numerical
simulations which are extended also to beams with cylindrical symmetry. The
theory explains recent experiments where such dispersive shock waves have been
observed.


title:
Symmetric linear functions of the restricted quantum group
  $\bar{U}_qsl_2(\mathbb{C})$

abstract:
  We determine a set of primitive idempotents and the basic algebra of the
restricted quantum group $\bar{U}_qsl_2(\mathbb{C})$. As a result, we can show
the dimension of the space of symmetric linear functions of
$\bar{U}_qsl_2(\mathbb{C})$ is $3p-1$


title:
Peculiarities of the hidden nonlinear supersymmetry of Poschl-Teller
  system in the light of Lame equation

abstract:
  A hidden nonlinear bosonized supersymmetry was revealed recently in
Poschl-Teller and finite-gap Lame systems. In spite of the intimate
relationship between the two quantum models, the hidden supersymmetry in them
displays essential differences. In particular, the kernel of the supercharges
of the Poschl-Teller system, unlike the case of Lame equation, includes
nonphysical states. By means of Lame equation, we clarify the nature of these
peculiar states, and show that they encode essential information not only on
the original hyperbolic Poschl-Teller system, but also on its singular
hyperbolic and trigonometric modifications, and reflect the intimate relation
of the model to a free particle system.


title:
Continuum quasiparticle linear response theory using the Skyrme
  functional for multipole responses of exotic nuclei

abstract:
  We develop a new formulation of the continuum quasiparticle random phase
approximation (QRPA) in which the residual interaction is derived directly from
the Skyrme energy functional, keeping all the velocity dependent terms of the
Skyrme effective interaction. Numerical analysis using the SkM$^*$ parameter
set is performed for the isovector dipole and the isovector/isoscalar
quadrupole responses in $^{20}$O and $^{54}$Ca. It is shown that the
energy-weighted sum rule including the enhancement factors for the isovector
responses is satisfied with good accuracy. We investigate also how the velocity
dependent terms influence the strength distribution and the transition
densities of the low-lying surface modes and the giant resonances.


title:
Sub-MHz Linewidth at 240 GHz from an Injection-Locked Free-Electron
  Laser

abstract:
  Radiation from an ultra-stable 240 GHz solid-state source has been injected,
through an isolator, into the cavity of the University of California Santa
Barbara (UCSB) MM-wave free-electron laser (FEL). High-power FEL emission,
normally distributed among many of the cavity's longitudinal modes, is
concentrated into the single mode to which the solid state source has been
tuned. The linewidth of the FEL emission is 0.5 MHz, consistent with the
Fourier transform limit for the 2 microsecond pulses. This demonstration of
frequency-stable, ultra-narrow-band FEL emission is a critical milestone on the
road to FEL-based pulsed electron paramagnetic resonance spectroscopy.


title: Rearrangement of the vortex lattice due to instabilities of vortex flow

abstract:
  With increasing applied current we show that the moving vortex lattice
changes its structure from a triangular one to a set of parallel vortex rows in
a pinning free superconductor. This effect originates from the change of the
shape of the vortex core due to non-equilibrium effects (similar to the
mechanism of vortex motion instability in the Larkin-Ovchinnikov theory). The
moving vortex creates a deficit of quasiparticles in front of its motion and an
excess of quasiparticles behind the core of the moving vortex. This results in
the appearance of a wake (region with suppressed order parameter) behind the
vortex which attracts other vortices resulting in an effective
direction-dependent interaction between vortices. When the vortex velocity $v$
reaches the critical value $v_c$ quasi-phase slip lines (lines with fast vortex
motion) appear which may coexist with slowly moving vortices between such
lines. Our results are found within the framework of the time-dependent
Ginzburg-Landau equations and are strictly valid when the coherence length
$\xi(T)$ is larger or comparable with the decay length $L_{in}$ of the
non-equilibrium quasiparticle distribution function. We qualitatively explain
experiments on the instability of vortex flow at low magnetic fields when the
distance between vortices $a \gg L_{in} \gg \xi (T)$. We speculate that a
similar instability of the vortex lattice should exist for $v>v_c$ even when
$a<L_{in}$.


title: Asynchronous games: innocence without alternation

abstract:
  The notion of innocent strategy was introduced by Hyland and Ong in order to
capture the interactive behaviour of lambda-terms and PCF programs. An innocent
strategy is defined as an alternating strategy with partial memory, in which
the strategy plays according to its view. Extending the definition to
non-alternating strategies is problematic, because the traditional definition
of views is based on the hypothesis that Opponent and Proponent alternate
during the interaction. Here, we take advantage of the diagrammatic
reformulation of alternating innocence in asynchronous games, in order to
provide a tentative definition of innocence in non-alternating games. The task
is interesting, and far from easy. It requires the combination of true
concurrency and game semantics in a clean and organic way, clarifying the
relationship between asynchronous games and concurrent games in the sense of
Abramsky and Melli\`es. It also requires an interactive reformulation of the
usual acyclicity criterion of linear logic, as well as a directed variant, as a
scheduling criterion.


title: Cointegration of the Daily Electric Power System Load and the Weather

abstract:
  The paper makes a thermal predictive analysis of the electric power system
security for a day ahead. This predictive analysis is set as a thermal
computation of the expected security. This computation is obtained by
cointegrating the daily electric power systen load and the weather, by finding
the daily electric power system thermodynamics and by introducing tests for
this thermodynamics. The predictive analysis made shows the electricity
consumers' wisdom.


title: Comparison Geometry for the Bakry-Emery Ricci Tensor

abstract:
  For Riemannian manifolds with a measure $(M,g, e^{-f} dvol_g)$ we prove mean
curvature and volume comparison results when the $\infty$-Bakry-Emery Ricci
tensor is bounded from below and $f$ is bounded or $\partial_r f$ is bounded
from below, generalizing the classical ones (i.e. when $f$ is constant). This
leads to extensions of many theorems for Ricci curvature bounded below to the
Bakry-Emery Ricci tensor. In particular, we give extensions of all of the major
comparison theorems when $f$ is bounded. Simple examples show the bound on $f$
is necessary for these results.


title: Controversy on a dispersion relation for MHD waves

abstract:
  Kumar et al. (2006) obtained a fifth order polynomial in $\omega$ for the
dispersion relation and pointed out that the calculations preformed by Porter
et al. (1994) and by Dwivedi & Pandey (2003) seem to be in error, as they
obtained a sixth order polynomial. The energy equation of Dwivedi & Pandey
(2003) was dimensionally wrong. Dwivedi & Pandey (2006) corrected the energy
equation and still claimed that the dispersion relation must be a sixth order
polynomial. The equations (11) $-$ (19) of Dwivedi & Pandey (2006) and the
equations (24) $-$ (32) Kumar et al. (2006) are the same. This fact has been
expressed by Kumar et al. (2006) themselves. Even then they tried to show this
set of equations on one side gives the sixth order polynomial as they got; on
the other side, the same set of equations gives the fifth order polynomial as
Kumar et al. (2006) obtained. The situation appears to be non-scientific, as
the system of equations is a linear one. These are simple algebraic equations
where the variables are to be eliminated. However, it is a matter of surprise
that by solving these equations, two scientific groups are getting polynomials
of different degrees. In the present discussion, we have attempted to short out
this discrepancy.


title: The richest superclusters. I. Morphology

abstract:
  We study the morphology of the richest superclusters from the catalogues of
superclusters of galaxies in the 2dF Galaxy Redshift Survey and compare the
morphology of real superclusters with model superclusters in the Millennium
Simulation. We use Minkowski functionals and shapefinders to quantify the
morphology of superclusters: their sizes, shapes, and clumpiness. We generate
empirical models of simple geometry to understand which morphologies correspond
to the supercluster shapefinders. We show that rich superclusters have
elongated, filamentary shapes with high-density clumps in their core regions.
The clumpiness of superclusters is determined using the fourth Minkowski
functional $V_3$. In the $K_1$-$K_2$ shapefinder plane the morphology of
superclusters is described by a curve which is characteristic to
multi-branching filaments. We also find that the differences between the fourth
Minkowski functional $V_3$ for the bright and faint galaxies in observed
superclusters are larger than in simulated superclusters.


title: Thurston obstructions and Ahlfors regular conformal dimension

abstract:
  Let $f: S^2 \to S^2$ be an expanding branched covering map of the sphere to
itself with finite postcritical set $P_f$. Associated to $f$ is a canonical
quasisymmetry class $\GGG(f)$ of Ahlfors regular metrics on the sphere in which
the dynamics is (non-classically) conformal. We show \[ \inf_{X \in \GGG(f)}
\hdim(X) \geq Q(f)=\inf_\Gamma \{Q \geq 2: \lambda(f_{\Gamma,Q}) \geq 1\}.\]
The infimum is over all multicurves $\Gamma \subset S^2-P_f$. The map
$f_{\Gamma,Q}: \R^\Gamma \to \R^\Gamma$ is defined by \[ f_{\Gamma, Q}(\gamma)
=\sum_{[\gamma']\in\Gamma} \sum_{\delta \sim \gamma'} \deg(f:\delta \to
\gamma)^{1-Q}[\gamma'],\] where the second sum is over all preimages $\delta$
of $\gamma$ freely homotopic to $\gamma'$ in $S^2-P_f$, and $
\lambda(f_{\Gamma,Q})$ is its Perron-Frobenius leading eigenvalue. This
generalizes Thurston's observation that if $Q(f)>2$, then there is no
$f$-invariant classical conformal structure.


title: Test ideals vs. multiplier ideals

abstract:
  The generalized test ideals introduced in [HY] are related to multiplier
ideals via reduction to characteristic p. In addition, they satisfy many of the
subtle properties of the multiplier ideals, which in characteristic zero follow
via vanishing theorems. In this note we give several examples to emphasize the
different behavior of test ideals and multiplier ideals. Our main result is
that every ideal in an F-finite regular local ring can be written as a
generalized test ideal. We also prove the semicontinuity of $F$-pure thresholds
(though the analogue of the Generic Restriction Theorem for multiplier ideals
does not hold).


title:
Polarization effects in the reaction $e^++e^-\to \rho^+ +\rho^- $ and
  determination of the $\rho -$ meson form factors in the time--like region

abstract:
  The electron positron annihilation reaction into four pion production has
been studied, through the channel $e^++e^-\to \bar \rho+\rho $. The
differential (and total) cross sections and various polarization observables
for this reaction have been calculated in terms of the electromagnetic form
factors of the corresponding $\gamma^*\rho\rho $ current. The elements of the
spin--density matrix of the $\rho -$meson were also calculated. Numerical
estimations have been done, with the help of phenomenological form factors
obtained in the space--like region of the momentum transfer squared and
analytically extended to the time-like region.


title: The richest superclusters. II. Galaxy populations

abstract:
  We study the morphology of galaxy populations of the richest superclusters
from the catalogue of superclusters of galaxies in the 2dF Galaxy Redshift
Survey using the luminosity density distribution and Minkowski functional V3.
We compare the properties of grouped and isolated galaxies in regions of
different density in superclusters. We find that in high-density cores of rich
superclusters there is an excess of early type, passive galaxies, among
galaxies in groups and clusters, as well as among those which do not belong to
groups, while in lower density outer regions there are more blue, star-forming
galaxies both in groups and among those galaxies which do not belong to groups.
This also shows that the galaxy content of groups depends on the environment
where the groups reside in. The density distributions and the behaviour of the
Minkowski functional V3 for different superclusters show that substructures in
superclusters as traced by different populations of galaxies are very
different. Our results show that both local (group/cluster) and global
(supercluster) environments are important in forming galaxy morphologies and
star formation activity. The presence of a high density core with X-ray
clusters and a relatively small fraction of star-forming galaxies in the
supercluster SCL126 may be an indication that this supercluster has started its
evolution earlier than the supercluster SCL9.


title:
Redesigning Computer-based Learning Environments: Evaluation as
  Communication

abstract:
  In the field of evaluation research, computer scientists live constantly upon
dilemmas and conflicting theories. As evaluation is differently perceived and
modeled among educational areas, it is not difficult to become trapped in
dilemmas, which reflects an epistemological weakness. Additionally, designing
and developing a computer-based learning scenario is not an easy task.
Advancing further, with end-users probing the system in realistic settings, is
even harder. Computer science research in evaluation faces an immense
challenge, having to cope with contributions from several conflicting and
controversial research fields. We believe that deep changes must be made in our
field if we are to advance beyond the CBT (computer-based training) learning
model and to build an adequate epistemology for this challenge. The first task
is to relocate our field by building upon recent results from philosophy,
psychology, social sciences, and engineering. In this article we locate
evaluation in respect to communication studies. Evaluation presupposes a
definition of goals to be reached, and we suggest that it is, by many means, a
silent communication between teacher and student, peers, and institutional
entities. If we accept that evaluation can be viewed as set of invisible rules
known by nobody, but somehow understood by everybody, we should add
anthropological inquiries to our research toolkit. The paper is organized
around some elements of the social communication and how they convey new
insights to evaluation research for computer and related scientists. We found
some technical limitations and offer discussions on how we relate to technology
at same time we establish expectancies and perceive others work.


title:
Dipole Oscillations in Bose - Fermi Mixture in the Time-Dependent
  Grosspitaevskii and Vlasov equations

abstract:
  We study the dipole collective oscillations in the bose-fermi mixture using a
dynamical time-dependent approach, which are formulated with the time-dependent
Gross-Pitaevskii equation and the Vlasov equation. We find big difference in
behaviors of fermion oscillation between the time-dependent approach and usual
approaches such as the random-phase approximation and the sum-rule approach.
While the bose gas oscillates monotonously, the fermion oscillation shows a
beat and a damping. When the amplitude is not minimal, the dipole oscillation
of the fermi gas cannot be described with a simple center-of-mass motion.


title: The nature of the infrared counterpart of IGR J19140+0951

abstract:
  The INTEGRAL observatory has been (re-)discovering new X-ray sources since
the beginning of nominal operations in early 2003. These sources include X-ray
binaries, Active Galactic Nuclei, cataclysmic variables, etc. Amongst the X-ray
binaries, the true nature of many of these sources has remained largely
elusive, though they seem to make up a population of highly absorbed high-mass
X-ray binaries. One of these new sources, IGR J19140+0951, was serendipitously
discovered on 2003 Mar 6 during an observation of the galactic microquasar GRS
1915+105. We observed IGR J19140+0951 with UKIRT in order to identify the
infrared counterpart. Here we present the H- and K-band spectra. We determined
that the companion is a B0.5-type bright supergiant in a wind-fed system, at a
distance $\la$ 5 kpc.


title:
A Communication Model for Adaptive Service Provisioning in Hybrid
  Wireless Networks

abstract:
  Mobile entities with wireless links are able to form a mobile ad-hoc network.
Such an infrastructureless network does not have to be administrated. However,
self-organizing principles have to be applied to deal with upcoming problems,
e.g. information dissemination. These kinds of problems are not easy to tackle,
requiring complex algorithms. Moreover, the usefulness of pure ad-hoc networks
is arguably limited. Hence, enthusiasm for mobile ad-hoc networks, which could
eliminate the need for any fixed infrastructure, has been damped. The goal is
to overcome the limitations of pure ad-hoc networks by augmenting them with
instant Internet access, e.g. via integration of UMTS respectively GSM links.
However, this raises multiple questions at the technical as well as the
organizational level. Motivated by characteristics of small-world networks that
describe an efficient network even without central or organized design, this
paper proposes to combine mobile ad-hoc networks and infrastructured networks
to form hybrid wireless networks. One main objective is to investigate how this
approach can reduce the costs of a permanent backbone link and providing in the
same way the benefits of useful information from Internet connectivity or
service providers. For the purpose of bridging between the different types of
networks, an adequate middleware service is the focus of our investigation.
This paper shows our first steps forward to this middleware by introducing the
Injection Communication paradigm as principal concept.


title: Hadron masses in QCD with one quark flavour

abstract:
  One-flavour QCD - a gauge theory with SU(3) colour gauge group and a fermion
in the fundamental representation - is studied by Monte Carlo simulations. The
mass spectrum of hadronic bound states is investigated in a volume with
extensions of L ~ 4.4r_0 (~2.2fm) at two different lattice spacings: a ~
0.37r_0 (~0.19fm) and a ~ 0.27r_0 (~0.13fm). The lattice action is Symanzik
tree-level-improved Wilson action for the gauge field and (unimproved) Wilson
action for the fermion.


title: From the microcosm of the atomic nuclei to the macrocosm of the stars

abstract:
  A necessary condition for the reliable modelling of the structure or
evolution of the stars and of their concomitant nucleosynthesis is the
availability of good quality nuclear data in a very wide area of the chart of
nuclides. This short review presents a non-exhaustive list of nuclear data of
astrophysics interest (masses, $\beta$-decays, thermonuclear and
non-thermonuclear reaction rates) for nuclides at the bottom of the valley of
nuclear stability (mainly involved in the modelling of non-explosive phases of
stellar evolution), or for more or less highly exotic nuclides (to be
considered in the description of stellar explosions). Special emphasis is put
on the importance of providing quality nuclear data bases that can be easily
used by astrophysicists.


title: Updated constraints on new physics in rare charm decays

abstract:
  Motivated by recent experimental results on charm physics we investigate
implications of the updated constraints of new physics in rare charm meson
decays. We first reconsider effects of the MSSM in $c\to u \gamma$ constrained
by the recent experimental evidence on $\Delta m_D$ and find, that due to the
dominance of long distance physics, $D \to V \gamma$ decay rates cannot be
modified by MSSM contributions. Then we consider effects of the extra heavy up
vector-like quark models on the decay spectrum of $D^+ \to \pi^+ l^+ l^-$ and
$D_s^+ \to K^+ l^+ l^-$ decays. We find a possibility for the tiny increase of
the differential decay rate in the region of large dilepton mass. The R-parity
violating supersymmetric model can also modify short distance dynamics in $c
\to u l^+ l^-$ decays. We constrain relevant parameters using current upper
bound on the $D^+ \to \pi^+ l^+ l^-$ decay rate and investigate impact of that
constraint on the $D_s^+ \to K^+ l^+ l^-$ differential decay dilepton
distribution. Present bounds still allow small modification of the standard
model differential decay rate distribution.


title:
Comment on: Failure of the work-Hamiltonian connection for free energy
  calculations

abstract:
  We argue that the apparent failure of the work-Hamiltonian connection for
free energy calculations reported by Vilar and Rubi' (cond-mat
arXiv:0704.0761v2) stems from their incorrect expression for the work.