title:
Descriptive set theoretic methods applied to strictly singular and
  strictly cosingular operators

abstract:
  The class of strictly singular operators originating from the dual of a
separable Banach space is written as an increasing union of $\omega_1$
subclasses which are defined using the Schreier sets. A question of J. Diestel,
of whether a similar result can be stated for strictly cosingular operators, is
studied.


title: Universal Record Statistics of Random Walks and L\'evy Flights

abstract:
  It is shown that statistics of records for time series generated by random
walks are independent of the details of the jump distribution, as long as the
latter is continuous and symmetric. In N steps, the mean of the record
distribution grows as the sqrt(4N/pi) while the standard deviation grows as
sqrt((2-4/pi) N), so the distribution is non-self-averaging. The mean shortest
and longest duration records grow as sqrt(N/pi) and 0.626508... N,
respectively. The case of a discrete random walker is also studied, and similar
asymptotic behavior is found.


title:
A new approach to the Ramsey-type games and the Gowers dichotomy in
  F-spaces

abstract:
  We give a new approach to the Ramsey-type results of Gowers on block bases in
Banach spaces and apply our results to prove the Gowers dichotomy in F-spaces.


title: Shock formation and the ideal shape of ramp compression waves

abstract:
  We derive expressions for shock formation based on the local curvature of the
flow characteristics during dynamic compression. Given a specific ramp adiabat,
calculated for instance from the equation of state for a substance, the ideal
nonlinear shape for an applied ramp loading history can be determined. We
discuss the region affected by lateral release, which can be presented in
compact form for the ideal loading history. Example calculations are given for
representative metals and plastic ablators. Continuum dynamics (hydrocode)
simulations were in good agreement with the algebraic forms. Example
applications are presented for several classes of laser-loading experiment,
identifying conditions where shocks are desired but not formed, and where long
duration ramps are desired.


title:
Sur l'existence d'une cat\'egorie ayant une matrice strictement positive
  donn\'ee

abstract:
  The Leinster matrix corresponding to a finite category has entries counting
the number of morphisms between objects. A first question is to know which
positive integer matrices come from at least one finite category. Here, that
question will be answered when the entries are strictly positive.


title:
Thermodynamic stabilities of ternary metal borides: An ab initio guide
  for synthesizing layered superconductors

abstract:
  Density functional theory calculations have been used to identify stable
layered Li-$M$-B crystal structure phases derived from a recently proposed
binary metal-sandwich (MS) lithium monoboride superconductor. We show that the
MS lithium monoboride gains in stability when alloyed with electron-rich metal
diborides; the resulting ordered Li$_{2(1-x)}M_x$B$_2$ ternary phases may form
under normal synthesis conditions in a wide concentration range of $x$ for a
number of group-III-V metals $M$. In an effort to pre-select compounds with the
strongest electron-phonon coupling we examine the softening of the in-plane
boron phonon mode at $\Gamma$ in a large class of metal borides. Our results
reveal interesting general trends for the frequency of the in-plane boron
phonon modes as a function of the boron-boron bond length and the valence of
the metal. One of the candidates with a promise to be an MgB$_2$-type
superconductor, Li$_2$AlB$_4$, has been examined in more detail: according to
our {\it ab initio} calculations of the phonon dispersion and the
electron-phonon coupling $\lambda$, the compound should have a critical
temperature of $\sim4$ K.


title:
Generating functions of stable pair invariants via wall-crossings in
  derived categories

abstract:
  The notion of limit stability on Calabi-Yau 3-folds is introduced by the
author to construct an approximation of Bridgeland-Douglas stability conditions
at the large volume limit. It has also turned out that the wall-crossing
phenomena of limit stable objects seem relevant to the rationality conjecture
of the generating functions of Pandharipande-Thomas invariants. In this
article, we shall make it clear how wall-crossing formula of the counting
invariants of limit stable objects solves the above conjecture.


title:
Very high critical field and superior Jc-field performance in
  NdO0.82F0.18FeAs with Tc of 51 K

abstract:
  The discovery of the new family of oxypnictide superconductors, such as
LaFeAsO0.89F0.1, with critical temperature, Tc, over 26 K, has brought new
impetus to the fields of high temperature superconductivity and strongly
correlated electron systems. These materials showed high upper critical fields,
Hc2, which have been estimated to be higher than 55 or 63-65 T in
LaO0.9F0.1FeAs with Tc of 26 K, 70 T in PrFeAsO0.85F0.15, and over 100 T in
SmO0.85F0.15FeAs with Tc of 46 K. The two gap superconductivity proposed for
LaO0.9F0.1FeAs suggests that the Hc2 could be further increased to a
significant extent. This is one of the unique features of the FeAs based new
superconductors. In this work, we show that the Bc2(48 K) = 13 T and the Bc2(0)
value can exceed 230 T in a high pressure fabricated NdO0.82F0.18FeAs bulk
sample with Tc of 51 K. We also demonstrate that the supercurrent density from
1 up to 9 T only drops by a factor of 2-6 for T < 30 K, much weaker than MgB2
and high Tc cuprate superconductors. The very high Bc2 already far surpasses
those of high Tc cuprates, MgB2, and classical low temperature superconductors,
paving the way to use the new NdO0.82F0.18FeAs superconductors for high-field
applications.


title:
The first $R_{cr}$ as a possible measure of the entrainment length in a
  2D steady wake

abstract:
  At a fixed distance from the body which creates the wake, entrainment is only
seen to increase with the Reynolds number ($R$) up to a distance of almost 20
body scales. This increase levels up to a Reynolds number close to the critical
value for the onset of the first instability. The entrainment is observed to be
almost extinguished at a distance which is nearly the same for all the steady
wakes within the $R$ range here considered, i.e. [20-100], which indicates that
supercritical steady wakes have the same entrainment length as the subcritical
ones. It is observed that this distance is equal to a number of body lengths
that is equal to the value of the critical Reynolds number ($\sim 47$), as
indicated by a large compilation of experimental results. {\it A fortiori} of
these findings, we propose to interpret the unsteady bifurcation as a process
that allows a smooth increase-redistribution of the entrainment along the wake
according to the weight of the convection over the diffusion. The entrainment
variation along the steady wake has been determined using a matched asymptotic
expansion of the Navier-Stokes velocity field [Tordella and Belan, {\it Physics
of Fluids}, 15(2003)] built on criteria that include the matching of the
transversal velocity produced by the entrainment process.


title: Infinity inner products on A-infinity algebras

abstract:
  We give a self contained introduction to A$_\infty$-algebras,
A$_\infty$-bimodules and maps between them. The case of A$_\infty$-bimodule-map
between $A$ and its dual space $A^{*}$, which we call $\infty$-inner-product,
will be investigated in detail. In particular, we describe the graph complex
associated to $\infty$-inner-product. In a later paper, we show how
$\infty$-inner-products can be used to model the string topology BV-algebra on
the free loop space of a Poincar\'e duality space.


title: Elliptic systems and material interpenetration

abstract:
  We classify the second order, linear, two by two systems for which the two
fundamental theorems for planar harmonic mappings, the Rado'-Kneser-Choquet
Theorem and the H. Lewy Theorem, hold. They are those which, up to a linear
change of variable, can be written in diagonal form with the same operator on
both diagonal blocks. In particular, we prove that the aforementioned Theorems
cannot be extended to solutions of either the Lame' system of elasticity, or of
elliptic systems in diagonal form, even with just slightly different operators
for the two components.


title: Exploring the substellar temperature regime down to ~550K

abstract:
  We report the discovery of three very late T dwarfs in the UKIRT Infrared
Deep Sky Survey (UKIDSS) Third Data Release: ULAS J101721.40+011817.9
(ULAS1017), ULAS J123828.51+095351.3 (ULAS1238) and ULAS J133553.45+113005.2
(ULAS1335).We detail optical and near-infrared photometry for all three
sources, and mid-infrared photometry for ULAS1335. We use near-infrared spectra
of each source to assign spectral types T8p (ULAS1017), T8.5 (ULAS1228) and T9
(ULAS1335) to these objects. We estimate that ULAS1017 has 750 < Teff < 850K,
and 5.0 < log g < 5.5, assuming solar metallicity, an age of 1.6-15 Gyr, a mass
of 33-70 MJ and lies at a distance of 31-54 pc. We extend the unified scheme of
Burgasser et al. (2006) to the type T9 and suggest the inclusion of the WJ
index to replace the now saturated J-band indices. ULAS1335 is the same
spectral type as ULAS J003402.77-005206.7 and CFBDS J005910.90-011401.3.
Comparison of model spectra with that of ULAS1335 suggest a temperature below
600K. We find ULAS1335 to be extremely red in near to mid-infrared colours,
with H-[4.49]=4.34+/-0.04. This is the reddest near to mid-infrared colour yet
observed for a T dwarf, which supports Teff < 600K, and we estimate Teff
~550-600K for ULAS1335. We estimate that ULAS1335 has an age of 0.6-5.3 Gyr, a
mass of 15-31 MJ and lies at a distance of 8-12 pc.


title:
An exploratory analysis of the transient and long term behaviour of
  small 3D perturbations in the circular cylinder wake

abstract:
  An initial-value problem for arbitrary small 3D vorticity perturbations
imposed on a free shear flow is considered. The viscous perturbation equations
are then combined in terms of the vorticity and velocity, and are solved by
means of a combined Laplace-Fourier transform in the plane normal to the basic
flow. This treatment allows for a simplification of the governing equations
such that it is possible to observe long transients, that can last hundreds
time scales. This result would not be possible over an acceptable lapse of time
by carrying out a direct numerical integration of the linearized Navier-Stokes
equations. The exploration is done with respect to physical inputs as the angle
of obliquity, the symmetry of the perturbation and the streamwise damping rate.
The base flow is an intermediate section of the growing 2D circular cylinder
wake where the entrainment process is still active. Two Reynolds numbers of the
order of the critical value for the onset of the first instability are
considered. The early transient evolution offers very different scenarios for
which we present a summary for particular cases. For example, for amplified
perturbations, we have observed two kinds of transients, namely (1) a monotone
amplification and (2) a sequence of growth - decrease - final growth. In the
latter case, if the initial condition is an asymmetric oblique or longitudinal
perturbation, the transient clearly shows an initial oscillatory time scale.
Furthermore, the more a perturbation is longitudinally confined the more it is
amplified in time. The long-term behavior of two-dimensional disturbances shows
excellent agreement with a recent two-dimensional spatio-temporal multiscale
modal analysis and with laboratory data concerning the frequency and wave
length of the parallel vortex shedding in the cylinder wake.


title: Single W and Anomalous Single Top Production at HERA

abstract:
  The search for events containing isolated leptons (electrons or muons) and
missing transverse momentum produced in e^{\pm}p collisions is performed
individually and in a common phase space with the H1 and ZEUS detectors at HERA
in the period 1994--2007. The presented H1+ZEUS data sample corresponds to an
integrated luminosity of 0.97 fb^{-1}, and comprises the complete high energy
data from the HERA programme. A total of 87 events are observed in the data,
compared to a Standard Model prediction of 92.7 \pm 11.2. At large hadronic
transverse momentum P_{T}^{X} > 25 GeV in the e^{+}p data, luminosity 0.58
fb^{-1}, 23 data events are observed compared to a SM prediction of 14.6 \pm
1.9. Production cross section measurements of events containing isolated
leptons and missing transverse momentum and of single W production are
performed by H1, where the measured cross sections are found to be in agreement
with SM predictions. A complementary search by H1 for events containing an
isolated tau lepton and missing P_{T} is also presented. A measurement of the W
polarisation fractions is performed by H1, where the presented results are
found to be in agreement with the SM. Finally, the H1 isolated lepton events
are examined in the context of a search for anomalous single top production. In
the absence of a clear signal, an upper limit on the anomalous top production
cross section \sigma_{ep\to etX} < 0.16 pb is established at the 95% confidence
level, corresponding to a limit an upper bound on the anomalous magnetic
coupling \kappa_{tu\gamma} < 0.14.


title: Superantenna made of transformation media

abstract:
  We show how transformation media can make a superantenna that is either
completely invisible or focuses incoming light into a needle-sharp beam. Our
idea is based on representating three-dimensional space as a foliage of sheets
and performing two-dimensional conformal maps on each sheet


title: Growing drift-cyclotron modes in the hot solar atmosphere

abstract:
  Well-known analytical results dealing with ion cyclotron and drift waves and
which follow from the kinetic theory are used and the dispersion equation,
which describes coupled two modes, is solved numerically. The numerical results
obtained by using the values for the plasma density, magnetic field and
temperature applicable to the solar corona clearly show the coupling and the
instability (growing) of the two modes. The coupling happens at very short
wavelengths, that are of the order of the ion gyro radius, and for
characteristic scale lengths of the equilibrium density that are altitude
dependent and may become of the order of only a few meters. The demonstrated
instability of the two coupled modes (driven by the equilibrium density
gradient) is obtained by using a rigorous kinetic theory model and for
realistic parameter values. The physical mechanism which is behind the coupling
is simple and is expected to take place throughout the solar atmosphere and the
solar wind which contain a variety of very elongated density structures of
various sizes. The mode grows on account of the density gradient, it is
essentially an ion mode, and its further dissipation should result in an
increased ion heating.


title: Gelfand-Tsetlin algebras and cohomology rings of Laumon spaces

abstract:
  Laumon moduli spaces are certain smooth closures of the moduli spaces of maps
from the projective line to the flag variety of GL_n. We calculate the
equivariant cohomology rings of the Laumon moduli spaces in terms of
Gelfand-Tsetlin subalgebra of U(gl_n), and formulate a conjectural answer for
the small quantum cohomology rings in terms of certain commutative shift of
argument subalgebras of U(gl_n).


title: An abstract Coifman-Rochberg-Weiss commutator theorem

abstract:
  We formulate and prove a version of the celebrated Coifman-Rochberg-Weiss
commutator theorem for the real method of interpolation


title: An X-ray spectral survey of the disc of M31 with XMM-Newton

abstract:
  We present the results of a complete spectral survey of the X-ray point
sources detected in five XMM-Newton observations along the major axis of M31
but avoiding the central bulge, aimed at establishing the population
characteristics of X-ray sources in this galaxy. We obtained background
subtracted spectra and lightcurves for each of the 335 X-ray point sources
detected across the five observations from 2002. We also correlate our source
list with those of earlier X-ray surveys and radio, optical and infra-red
catalogues. Sources with more than 50 source counts are individually spectrally
fit in order to create the most accurate luminosity functions of M31 to date.
Based on the spectral fitting of these sources with a power law model, we
observe a broad range of best fit photon index. From this distribution of best
fit index, we identify 16 strong high mass X-ray binary system candidates in
M31. We show the first cumulative luminosity functions created using the best
fit spectral model to each source with more than 50 source counts in the disc
of M31. The cumulative luminosity functions show a prominent, statistically
significant flattening in the X-ray luminosity LX interval 37.0 \lesssim log LX
erg s-1 \lesssim 37.5. Such a feature may also be present in the X-ray
populations of several other galaxies, but at a much lower statistical
significance. We investigate the number of AGN present in our source list and
find that above LX ~1.4x1036 erg s-1 the observed population is statistically
dominated by the point source population of M31.


title: An Experimental Investigation of XML Compression Tools

abstract:
  This paper presents an extensive experimental study of the state-of-the-art
of XML compression tools. The study reports the behavior of nine XML
compressors using a large corpus of XML documents which covers the different
natures and scales of XML documents. In addition to assessing and comparing the
performance characteristics of the evaluated XML compression tools, the study
tries to assess the effectiveness and practicality of using these tools in the
real world. Finally, we provide some guidelines and recommen- dations which are
useful for helping developers and users for making an effective decision for
selecting the most suitable XML compression tool for their needs.


title:
Equation of State for a van der Waals Universe during Reissner-Nordstrom
  Expansion

abstract:
  In a previous work [E.M. Prodanov, R.I. Ivanov, and V.G. Gueorguiev,
Reissner-Nordstrom Expansion, Astroparticle Physics 27 (150-154) 2007], we
proposed a classical model for the expansion of the Universe during the
radiation-dominated epoch based on the gravitational repulsion of the
Reissner-Nordstrom geometry - naked singularity description of particles that
"grow" with the drop of the temperature. In this work we model the Universe
during the Reissner-Nordstrom expansion as a van der Waals gas and determine
the equation of state.


title:
Single spin optical read-out in CdTe/ZnTe quantum dot studied by photon
  correlation spectroscopy

abstract:
  Spin dynamics of a single electron and an exciton confined in CdTe/ZnTe
quantum dot is investigated by polarization-resolved correlation spectroscopy.
Spin memory effects extending over at least a few tens of nanoseconds have been
directly observed in magnetic field and described quantitatively in terms of a
simple rate equation model. We demonstrate an effective (68%) all-optical
read-out of the single carrier spin state through probing the degree of
circular polarization of exciton emission after capture of an oppositely
charged carrier. The perturbation introduced by the pulsed optical excitation
serving to study the spin dynamics has been found to be the main source of the
polarization loss in the read-out process. In the limit of low laser power the
read-out efficiency extrapolates to a value close to 100%. The measurements
allowed us as well to determine neutral exciton spin relaxation time ranging
from 3.4 +/- 0.1 ns at B = 0 T to 16 +/- 3 ns at B = 5 T.


title:
Doping-insensitive density-of-states suppression in polycrystalline
  iron-based superconductor SmO$_{1-x}$F$_{x}$FeAs

abstract:
  We investigated the temperature dependence of the density-of-states in the
iron-based superconductor SmO_1-xF_xFeAs (x=0, 0.12, 0.15, 0.2) with high
resolution angle-integrated photoemission spectroscopy. The density-of-states
suppression is observed with decreasing temperature in all samples, revealing
two characteristic energy scales (10meV and 80meV). However, no obvious doping
dependence is observed. We argue that the 10meV suppression is due to an
anomalously doping-independent normal state pseudogap, which becomes the
superconducting gap once in the superconducting state; and alert the
possibility that the 80meV-scale suppression might be an artifact of the
polycrystalline samples.


title: Overview of charm production at RHIC

abstract:
  We present an overview of the recent abundant measurements for charm
production at RHIC. The significant information of charm cross sections in
different collision system at 200 GeV and charmed hadron freeze-out and flow
properties extracted from these measurements are presented. The heavy flavor
energy loss in the medium and heavy flavor related azimuthal correlations in
heavy ion collisions are also discussed.


title:
Outer Bounds for Multiple Access Channels with Feedback using Dependence
  Balance

abstract:
  We use the idea of dependence balance to obtain a new outer bound for the
capacity region of the discrete memoryless multiple access channel with
noiseless feedback (MAC-FB). We consider a binary additive noisy MAC-FB whose
feedback capacity is not known. The binary additive noisy MAC considered in
this paper can be viewed as the discrete counterpart of the Gaussian MAC-FB.
Ozarow established that the capacity region of the two-user Gaussian MAC-FB is
given by the cut-set bound. Our result shows that for the discrete version of
the channel considered by Ozarow, this is not the case. Direct evaluation of
our outer bound is intractable due to an involved auxiliary random variable
whose large cardinality prohibits an exhaustive search. We overcome this
difficulty by using functional analysis to explicitly evaluate our outer bound.
Our outer bound is strictly less than the cut-set bound at all points on the
capacity region where feedback increases capacity. In addition, we explicitly
evaluate the Cover-Leung achievable rate region for the binary additive noisy
MAC-FB in consideration. Furthermore, using the tools developed for the
evaluation of our outer bound, we also explicitly characterize the boundary of
the feedback capacity region of the binary erasure MAC, for which the
Cover-Leung achievable rate region is known to be tight. This last result
confirms that the feedback strategies developed by Kramer for the binary
erasure MAC are capacity achieving.


title: Canonical calculi with (n,k)-ary quantifiers

abstract:
  Propositional canonical Gentzen-type systems, introduced in 2001 by Avron and
Lev, are systems which in addition to the standard axioms and structural rules
have only logical rules in which exactly one occurrence of a connective is
introduced and no other connective is mentioned. A constructive coherence
criterion for the non-triviality of such systems was defined and it was shown
that a system of this kind admits cut-elimination iff it is coherent. The
semantics of such systems is provided using two-valued non-deterministic
matrices (2Nmatrices). In 2005 Zamansky and Avron extended these results to
systems with unary quantifiers of a very restricted form. In this paper we
substantially extend the characterization of canonical systems to (n,k)-ary
quantifiers, which bind k distinct variables and connect n formulas, and show
that the coherence criterion remains constructive for such systems. Then we
focus on the case of k∈{0,1} and for a canonical calculus G show that it
is coherent precisely when it has a strongly characteristic 2Nmatrix, which in
turn is equivalent to admitting strong cut-elimination.


title:
Global Solution to Enskog Equation with External Force in Infinite
  Vacuum

abstract:
  We first give hypotheses of the bicharacteristic equations corresponding to
the Enskog equation with an external force. Since the collision operator of the
Enskog equation is more complicated than that of the Boltzmann equation, these
hypotheses are more complicated than those given by Duan et al. for the
Boltzmann equation. The hypotheses are very related to collision of particles
of moderately or highly dense gases along the bicharacteristic curves and they
can be used to make the estimation of the so-called gain and loss integrals of
the Enskog integral equation. Then, by controlling these integrals, we show the
existence and uniqueness of the global mild solution to the Enskog equation in
an infinite vacuum for moderately or highly dense gases. Finally, we make some
remarks on the locally Lipschitz assumption of the collision factors in the
Enskog equation.


title:
Photodissociation of small carbonaceous molecules of astrophysical
  interest

abstract:
  Astronomical observations have shown that small carbonaceous molecules can
persist in interstellar clouds exposed to intense ultraviolet radiation.
Current astrochemical models lack quantitative information on photodissociation
rates in order to interpret these data. We here present ab initio
multi-reference configuration-interaction calculations of the vertical
excitation energies, transition dipole moments and oscillator strengths for a
number of astrophysically relevant molecules: C3, C4, C2H, l- and c-C3H, l- and
c-C3H2, HC3H, l-C4H and l-C5H. Highly excited states up to the 9'th root of
each symmetry are computed, and several new states with large oscillator
strengths are found below the ionization potentials. These data are used to
calculate upper limits on photodissociation rates in the unattenuated
interstellar radiation field by assuming that all absorptions above the
dissociation limit lead to dissociation.


title: Muscle fatigue degrades force sense at the ankle joint

abstract:
  To investigate the effects of muscle fatigue on force sense at the ankle
joint, 10 young healthy adults were asked to perform an isometric
contra-lateral force ankle-matching task in two experimental conditions of: (1)
no-fatigue and (2) fatigue of the plantar-flexor muscles. Measures of the
overall accuracy and the variability of the force matching performances were
determined using the absolute error and the variable error, respectively.
Results showed less accurate and less consistent force matching performances in
the fatigue than no fatigue condition, as indicated by decreased absolute and
variable errors, respectively. The present findings evidence that muscle
fatigue degrades force sense at the ankle joint.


title:
Isotropic transformation optics: approximate acoustic and quantum
  cloaking

abstract:
  Transformation optics constructions have allowed the design of
electromagnetic, acoustic and quantum parameters that steer waves around a
region without penetrating it, so that the region is hidden from external
observations. The material parameters are anisotropic, and singular at the
interface between the cloaked and uncloaked regions, making physical
realization a challenge.
  We address this problem by showing how to construct {\sl isotropic and
nonsingular} parameters that give {\sl approximate} cloaking to any desired
degree of accuracy for electrostatic, acoustic and quantum waves. The
techniques used here may be applicable to a wider range of transformation
optics designs.
  For the Helmholtz equation, cloaking is possible outside a discrete set of
frequencies or energies, namely the Neumann eigenvalues of the cloaked region.
For the frequencies or energies corresponding to the Neumann eigenvalues of the
cloaked region, the ideal cloak supports trapped states; near these energies,
an approximate cloak supports {\sl almost trapped states}. This is in fact a
useful feature, and we conclude by giving several quantum mechanical
applications.


title: Long distance quantum key distribution without decoy state

abstract:
  We present a method without decoy state to estimate faithfully and
efficiently the yield and quantum bit error rate of single photon pulse for
BB84 protocol. The numerical calculations show that key generation rate and
maximal secure communication distance of our method are better than results of
the decoy state method. As we know, it is the first time we present this method
and the idea is very novel. Furthermore, our method can overcome the drawbacks
of decoy state method. In our method, the maximal secure distance is
insensitive to the deviation of dark count rate from exact value.


title:
Postural destabilization induced by trunk extensor muscles fatigue is
  suppressed by use of a plantar pressure-based electro-tactile biofeedback

abstract:
  Separate studies have reported that postural control during quiet standing
could be (1) impaired with muscle fatigue localized at the lower back, and (2)
improved through the use of plantar pressure-based electro-tactile biofeedback,
under normal neuromuscular state. The aim of this experiment was to investigate
whether this biofeedback could reduce postural destabilization induced by trunk
extensor muscles. Ten healthy adults were asked to stand as immobile as
possible in four experimental conditions: (1) no fatigue/no biofeedback, (2) no
fatigue/biofeedback, (3) fatigue/no biofeedback and (4) fatigue/biofeedback.
Muscular fatigue was achieved by performing trunk repetitive extensions until
maximal exhaustion. The underlying principle of the biofeedback consisted of
providing supplementary information related to foot sole pressure distribution
through electro-tactile stimulation of the tongue. Centre of foot pressure
(CoP) displacements were recorded using a force platform. Results showed (1)
increased CoP displacements along the antero-posterior axis in the fatigue than
no fatigue condition in the absence of biofeedback and (2) no significant
difference between the no fatigue and fatigue conditions in the presence of
biofeedback. This suggests that subjects were able to efficiently integrate an
artificial plantar pressure information delivered through electro-tactile
stimulation of the tongue that allowed them to suppress the destabilizing
effect induced by trunk extensor muscles fatigue.


title: Photoprocesses in protoplanetary disks

abstract:
  Circumstellar disks are exposed to intense ultraviolet radiation from the
young star. In the inner disks, the UV radiation can be enhanced by more than
seven orders of magnitude compared with the average interstellar field,
resulting in a physical and chemical structure that resembles that of a dense
photon-dominated region (PDR). This intense UV field affects the chemistry, the
vertical structure of the disk, and the gas temperature, especially in the
surface layers of the disk. The parameters which make disks different from
traditional PDRs are discussed, including the shape of the UV radiation field,
grain growth, the absence of PAHs, the gas/dust ratio and the presence of inner
holes. New photorates for selected species, including simple ions, are
presented. Also, a summary of available cross sections at Lyman alpha 1216 A is
made. Rates are computed for radiation fields with color temperatures ranging
from 4000 to 30,000 K, and can be applied to a wide variety of astrophysical
regions including exo-planetary atmospheres. The importance of photoprocesses
is illustrated for a number of representative disk models, including disk
models with grain growth and settling.


title: On the equations for universal torsors over del Pezzo surfaces

abstract:
  We show that every split del Pezzo surface of degree d=5,4,3 or 2 has a
universal torsor which is a dense open subset of the intersection of 6-d
dilatations of the affine cone over the corresponding generalized Grassmannian
G/P. Here a dilatation is the linear transformation by an element of the
'diagonal' torus. This gives a concise description of the quadratic equations
of universal torsors obtained by Popov and Derenthal. Any (possibly, non-split)
del Pezzo surface with a rational point has a universal torsor which embeds
into the same homogeneous space as a split surface of the same degree. The
proof uses a recent result of Ph. Gille and Raghunathan.


title: Structure Theorem for Riemannian surfaces with arbitrary curvature

abstract:
  In this paper we prove that any Riemannian surface, with no restriction of
curvature at all, can be decomposed into blocks belonging just to some of these
types: generalized Y-pieces, generalized funnels and halfplanes.


title:
Low-x QCD studies with forward jets in proton-proton collisions at 14
  TeV

abstract:
  The Large Hadron Collider will provide hadronic collisions at energies in the
multi-TeV range, never explored before. The parton fractional momenta probed at
such energies can be as low as x~2p_T/\sqrt(s) e^(-y)~10^-5 at large rapidities
y, opening up attractive opportunities for low-x QCD studies. The combination
of the CMS HF (3$<|\eta|<$5) and CASTOR (5.1<|\eta|<6.6) calorimeters allows
one, in particular, to reconstruct very forward jets. We present
generator-level studies of the CMS capabilities to measure the single inclusive
forward jet spectrum and forward-backward (Mueller-Navelet) dijets in p-p
collisions at 14 TeV. Both observables are sensitive to low-x gluon densities
and non-linear QCD evolution.


title: Asymptotically tight bounds on subset sums

abstract:
  For a subset A of a finite abelian group G we define Sigma(A)={sum_{a\in
B}a:B\subset A}. In the case that Sigma(A) has trivial stabiliser, one may
deduce that the size of Sigma(A) is at least quadratic in |A|; the bound
|Sigma(A)|>= |A|^{2}/64 has recently been obtained by De Vos, Goddyn, Mohar and
Samal. We improve this bound to the asymptotically best possible result
|Sigma(A)|>= (1/4-o(1))|A|^{2}.
  We also study a related problem in which A is any subset of Z_{n} with all
elements of A coprime to n; it has recently been shown, by Vu, that if such a
set A has the property Sigma(A) is not Z_{n} then |A|=O(sqrt{n}). This bound
was improved to |A|<= 8sqrt{n} by De Vos, Goddyn, Mohar and Samal, we further
improve the bound to the asymptotically best possible result |A|<=
(2+o(1))sqrt{n}.


title:
A real variable characterization of Gromov hyperbolicity of flute
  surfaces

abstract:
  In this paper we give a characterization of the Gromov hyperbolicity of
trains (a large class of Denjoy domains which contains the flute surfaces) in
terms of the behavior of a real function. This function describes somehow the
distances between some remarkable geodesics in the train. This theorem has
several consequences; in particular, it allows to deduce a result about
stability of hyperbolicity, even though the original surface and the modified
one are not quasi-isometric.


title: Domain walls in gapped graphene

abstract:
  The electronic properties of a particular class of domain walls in gapped
graphene are investigated. We show that they can support mid-gap states which
are localized in the vicinity of the domain wall and propagate along its
length. With a finite density of domain walls, these states can alter the
electronic properties of gapped graphene significantly. If the mid-gap band is
partially filled,the domain wall can behave like a one-dimensional metal
embedded in a semi-conductor, and could potentially be used as a single-channel
quantum wire.


title:
Inter-impurity and impurity-host magnetic correlations in semiconductors
  with low-density transition-metal impurities

abstract:
  Experiments on (Ga,Mn)As in the low-doping insulating phase have shown
evidence for the presence of an impurity band at 110 meV above the valence
band. The motivation of this paper is to investigate the role of the impurity
band in determining the magnetic correlations in the low-doping regime of the
dilute magnetic semiconductors. For this purpose, we present results on the
Haldane-Anderson model of transition-metal impurities in a semiconductor host,
which were obtained by using the Hirsch-Fye Quantum Monte Carlo (QMC)
algorithm. In particular, we present results on the impurity-impurity and
impurity-host magnetic correlations in two and three-dimensional semiconductors
with quadratic band dispersions. In addition, we use the tight-binding
approximation with experimentally-determined parameters to obtain the host band
structure and the impurity-host hybridization for Mn impurities in GaAs. When
the chemical potential is located between the top of the valence band and the
impurity bound state (IBS), the impurities exhibit ferromagnetic (FM)
correlations with the longest range. We show that these FM correlations are
generated by the antiferromagnetic coupling of the host electronic spins to the
impurity magnetic moment. Finally, we obtain an IBS energy of 100 meV, which is
consistent with the experimental value of 110 meV, by combining the QMC
technique with the tight-binding approach for a Mn impurity in GaAs.


title: More efficient Bell inequalities for Werner states

abstract:
  In this paper we study the nonlocal properties of two-qubit Werner states
parameterized by the visibility parameter 0<p<1. New family of Bell
inequalities are constructed which prove the two-qubit Werner states to be
nonlocal for the parameter range 0.7056<p<1. This is slightly wider than the
range 0.7071<p<1, corresponding to the violation of the
Clauser-Horne-Shimony-Holt (CHSH) inequality. This answers a question posed by
Gisin in the positive, i.e., there exist Bell inequalities which are more
efficient than the CHSH inequality in the sense that they are violated by a
wider range of two-qubit Werner states.


title:
Gromov hyperbolicity of Denjoy domains with hyperbolic and
  quasihyperbolic metrics

abstract:
  We obtain explicit and simple conditions which in many cases allow one
decide, whether or not a Denjoy domain endowed with the Poincare or
quasihyperbolic metric is Gromov hyperbolic. The criteria are based on the
Euclidean size of the complement. As a corollary, the main theorem allows to
deduce the non-hyperbolicity of any periodic Denjoy domain.


title: Quantum many-body theory of qubit decoherence in a finite-size spin bath

abstract:
  Decoherence of a center spin or qubit in a spin bath is essentially
determined by the many-body bath evolution. We develop a cluster-correlation
expansion (CCE) theory for the spin bath dynamics relevant to the qubit
decoherence problem. A cluster correlation term is recursively defined as the
evolution of a group of bath spins divided by the cluster correlations of all
the subgroups. The so-defined correlation accounts for the authentic collective
excitations within a given group. The bath propagator is the product of all
possible cluster correlation terms. For a finite-time evolution as in the qubit
decoherence problem, a convergent result can be obtained by truncating the
expansion up to a certain cluster size. The two-spin cluster truncation of the
CCE corresponds to the pair-correlation approximation [PRB 74,195301(2006)]. In
terms of the standard linked cluster expansion, a cluster correlation term is
the infinite summation of all the connected diagrams with all and only the
spins in the group flip-flopped, and thus the expansion is exact whenever
converges. When the individual contribution of each higher-order correlation
term to the decoherence is small, as the usual case for relatively large baths
where the decoherence could complete well within the bath spin flip-flop time,
the CCE coincides with the cluster expansion [PRB 74,035322(2006)]. For small
baths, however, the qubit decoherence may not complete within the bath spin
flip-flop timescale and thus individual higher-order cluster correlations could
grow significant. In such cases, only the CCE converges to the exact coherent
dynamics of multi-spin clusters. We check the accuracy of the CCE in an exactly
solvable spin-chain model.


title:
The Swift Discovery of X-ray Afterglows Accompanying Short Bursts from
  SGR 1900+14

abstract:
  The discovery of X-ray afterglows accompanying two short bursts from SGR
1900+14 is presented. The afterglow luminosities at the end of each observation
are lower by 30-50% than their initial luminosities, and decay with power law
indices p ~ 0.2-0.4. Their initial bolometric luminosities are L ~ 10^34-10^35
erg s^-1. We discuss analogies and differences between the X-ray afterglows of
SGR short bursts and short gamma-ray bursts.


title:
Random Attractors for the Stochastic FitzHugh-Nagumo System on Unbounded
  Domains

abstract:
  The existence of a random attractor for the stochastic FitzHugh-Nagumo system
defined on an unbounded domain is established. The pullback asymptotic
compactness of the stochastic system is proved by uniform estimates on
solutions for large space and time variables. These estimates are obtained by a
cut-off technique.


title:
Coherent quasi-particles-to-incoherent hole-carriers crossover in
  underdoped cuprates

abstract:
  In underdoped cuprates, only a portion of the Fermi surface survives as Fermi
arcs due to pseudogap opening. In hole-doped La$_{2}$CuO$_4$, we have deduced
the "coherence temperature" $T_{coh}$ of quasi-particles on the Fermi arc above
which the broadened leading edge position in angle-integrated photoemission
spectra is shifted away from the Fermi level and the quasi-particle concept
starts to lose its meaning. $T_{coh}$ is found to rapidly increase with hole
doping, an opposite behavior to the pseudogap temperature $T^*$. The
superconducting dome is thus located below both $T^*$ and $T_{coh}$, indicating
that the superconductivity emerges out of the coherent Fermionic
quasi-particles on the Fermi arc. $T_{coh}$ remains small in the underdoped
region, indicating that incoherent charge carriers originating from the Fermi
arc are responsible for the apparently metallic transport at high temperatures.


title: GUTs and Exceptional Branes in F-theory - II: Experimental Predictions

abstract:
  We consider realizations of GUT models in F-theory. Adopting a bottom up
approach, the assumption that the dynamics of the GUT model can in principle
decouple from Planck scale physics leads to a surprisingly predictive
framework. An internal U(1) hypercharge flux Higgses the GUT group directly to
the MSSM or to a flipped GUT model, a mechanism unavailable in heterotic
models. This new ingredient automatically addresses a number of puzzles present
in traditional GUT models. The internal U(1) hyperflux allows us to solve the
doublet-triplet splitting problem, and explains the qualitative features of the
distorted GUT mass relations for lighter generations due to the Aharanov-Bohm
effect. These models typically come with nearly exact global symmetries which
prevent bare mu terms and also forbid dangerous baryon number violating
operators. Strong curvature around our brane leads to a repulsion mechanism for
Landau wave functions for neutral fields. This leads to large hierarchies of
the form exp(-c/B^(2*g)) where c and g are order one parameters and B ~
M_(GUT)/(M_(pl)*alpha_(GUT)). This effect can simultaneously generate a viably
small mu term as well as an acceptable Dirac neutrino mass on the order of 0.5
* 10^(-2 +/- 0.5) eV. In another scenario, we find a modified seesaw mechanism
which predicts that the light neutrinos have masses in the expected range while
the Majorana mass term for the heavy neutrinos is ~ 3 * 10^(12 +/- 1.5) GeV.
Communicating supersymmetry breaking to the MSSM can be elegantly realized
through gauge mediation. In one scenario, the same repulsion mechanism also
leads to messenger masses which are naturally much lighter than the GUT scale.


title: A note on clique-width and tree-width for structures

abstract:
  We give a simple proof that the straightforward generalisation of
clique-width to arbitrary structures can be unbounded on structures of bounded
tree-width. This can be corrected by allowing fusion of elements.


title: New demonstrations about the resolution of numbers into squares

abstract:
  Translated from the Latin original "Novae demonstrationes circa resolutionem
numerorum in quadrata" (1774). E445 in the Enestrom index. See Chapter III,
section XI of Weil's "Number theory: an approach through history". Also, a very
clear proof of the four squares theorem based on Euler's is Theorem 370 in
Hardy and Wright, "An introduction to the theory of numbers", fifth ed. It uses
Theorem 87 in Hardy and Wright, but otherwise does not assume anything else
from their book. I translated most of the paper and checked those details a few
months ago, but only finished last few parts now. If anything isn't clear
please email me.


title:
Analytical and numerical modeling of front propagation and interaction
  of fronts in nonlinear thermoviscous fluids including dissipation

abstract:
  A wave equation, that governs finite amplitude acoustic disturbances in a
thermoviscous Newtonian fluid, and includes nonlinear terms up to second order,
is proposed. In contrast to the model known as the Kuznetsov equation, the
proposed nonlinear wave equation preserves the Hamiltonian structure of the
fundamental fluid dynamical equations in the non-dissipative limit. An exact
traveling front solution is obtained from a generalized traveling wave
assumption. This solution is, in an overall sense, equivalent to the Taylor
shock solution of the Burgers equation. However, in contrast to the Burgers
equation, the model equation considered here is capable to describe waves
propagating in opposite directions. Owing to the Hamiltonian structure of the
proposed model equation, the front solution is in agreement with the classical
Rankine-Hugoniot relations. The exact front solution propagates at supersonic
speed with respect to the fluid ahead of it, and subsonic speed with respect to
the fluid behind it, similarly to the fluid dynamical shock. Linear stability
analysis reveals that the front is stable when the acoustic pressure belongs to
a critical interval, and is otherwise unstable. These results are verified
numerically. Studies of head-on colliding fronts demonstrate that the front
propagation speed changes upon collision.


title:
Alternative scattering power for Gaussian beam model of heavy charged
  particles

abstract:
  This study provides an accurate, efficient, and simple multiple scattering
formulation for heavy charged particles such as protons and heavier ions with a
new form of scattering power that is a key quantity for beam transport in
matter. The Highland formula for multiple scattering angle was modified to a
scattering-power formula to be used within the Fermi-Eyges theory in the
presence of heterogeneity. An analytical formula for RMS end-point displacement
in homogeneous matter was also derived for arbitrary ions. The formulation was
examined in terms of RMS angles and displacements in comparison with other
formulations and measurements. The results for protons, helium ions, and carbon
ions in water agreed with them at a level of 2% or the differences were
discussed.


title: Hodge theoretic aspects of mirror symmetry

abstract:
  We discuss the Hodge theory of algebraic non-commutative spaces and analyze
how this theory interacts with the Calabi-Yau condition and with mirror
symmetry. We develop an abstract theory of non-commutative Hodge structures,
investigate existence and variations, and propose explicit construction and
classification techniques. We study the main examples of non-commutative Hodge
structures coming from a symplectic or a complex geometry possibly twisted by a
potential. We study the interactions of the new Hodge theoretic invariants with
mirror symmetry and derive non-commutative analogues of some of the more
interesting consequences of Hodge theory such as unobstructedness and the
construction of canonical coordinates on moduli.


title: The C-value enigma and timing of the Cambrian explosion

abstract:
  The Cambrian explosion is a grand challenge to science today and involves
multidisciplinary study. This event is generally believed as a result of
genetic innovations, environmental factors and ecological interactions, even
though there are many conflicts on nature and timing of metazoan origins. The
crux of the matter is that an entire roadmap of the evolution is missing to
discern the biological complexity transition and to evaluate the critical role
of the Cambrian explosion in the overall evolutionary context. Here we
calculate the time of the Cambrian explosion by an innovative and accurate
"C-value clock"; our result (560 million years ago) quite fits the fossil
records. We clarify that the intrinsic reason of genome evolution determined
the Cambrian explosion. A general formula for evaluating genome size of
different species has been found, by which major questions of the C-value
enigma can be solved and the genome size evolution can be illustrated. The
Cambrian explosion is essentially a major transition of biological complexity,
which corresponds to a turning point in genome size evolution. The observed
maximum prokaryotic complexity is just a relic of the Cambrian explosion and it
is supervised by the maximum information storage capability in the observed
universe. Our results open a new prospect of studying metazoan origins and
molecular evolution.


title: The holographic principle and the language of genes

abstract:
  We show that the holographic principle in quantum gravity imposes a strong
constraint on life. The degrees of freedom of an organism can be estimated
according to the theory of Boolean networks, which is constrained by the
entropy bound. Hence we can explain the languages in protein sequences or in
DNA sequences. The overall evolution of biological complexity can be
illustrated. And some general properties of protein length distributions can be
explained by a linguistic mechanism.


title: Universal conductivity and central charges

abstract:
  We discuss a class of critical models in d>1+1 dimensions whose electrical
conductivity and charge susceptibility are fixed by the central charge in a
universal manner. We comment on possible bounds on conductivity, as suggested
by holographic duality.


title:
A generalization of Cachazo-Douglas-Seiberg-Witten conjecture for
  symmetric spaces

abstract:
  We extend the original Cachazo-Douglas-Seiberg-Witten conjecture for
symmetric spaces.


title: On iterating operators and on generalized periodic orbits

abstract:
  We try to define the more general form of iterative processes in which the
Pomeau-Manneville and the Feigenbaum scenario may occur along with their
specific scaling properties. Doing this we need to generalize other basic
concepts. Thus, what we call a periodic carousel is a generalization of what is
usually called a periodic orbit.


title: A revised catalogue of EGRET gamma-ray sources

abstract:
  We present a catalog of point gamma-ray sources detected by the EGRET
detector aboard the Compton Gamma Ray Observatory. We have used the whole
gamma-ray dataset of reprocessed photons at energies above 100 MeV together
with new Galactic interstellar emission models based on recent CO, HI, dark
gas, and interstellar radiation field data. Two different assumptions have been
used for the cosmic-ray distribution in the Galaxy to explore the resulting
systematic uncertainties in source detection and characterization. We have used
the same 2-dimensional maximum-likelihood detection method as for the 3rd EGRET
catalogue. The revised catalogue lists 188 sources, 14 of which are marked as
confused, compared to the 271 entries of the 3rd EGRET (3EG) catalogue. 107
former sources have not been confirmed because of the additional structure in
the interstellar background. The vast majority of them were unidentified and
marked as possibly extended or confused in the 3EG catalogue. In particular, we
do not confirm most of the 3EG sources associated with the local clouds of the
Gould Belt. Alternatively, we find 30 new sources with no 3EG counterpart. The
new error circles for the confirmed 3EG sources largely overlap the previous
ones, but several counterparts of particular interest that had been discussed
in the litterature, such as Sgr A*, radiogalaxies and several microquasars are
now found outside the error circles. We have cross-correlated the source
positions with a large number of radio pulsars, pulsar wind nebulae, supernova
remnants, OB associations, blazars and flat radiosources and we find a
surprising large number of sources (87) at all latitudes with no counterpart
among the potential gamma-ray emitters.


title: Loops in the Reggeon model for hA scattering

abstract:
  Contribution of simplest loops is studied in the Local Reggeon Field Theory
with a supercritical pomeron in the nuclear matter. It is shown that the latter
transforms the supercritical pomeron into the subcritical. Renormalization of
the intercept and difficulties related to the fact that the renormalized
intercept is complex are discussed. Numerical results with the conventional
parameters are reported.


title:
Nonlocal entanglement concentration scheme for partially entangled
  multipartite systems with nonlinear optics

abstract:
  We present a nonlocal entanglement concentration scheme for reconstructing
some maximally entangled multipartite states from partially entangled ones by
exploiting cross-Kerr nonlinearities to distinguish the parity of two
polarization photons. Compared with the entanglement concentration schemes
based on two-particle collective unitary evolution, this scheme does not
require the parties to know accurately information about the partially
entangled states--i.e., their coefficients. Moreover, it does not require the
parties to possess sophisticated single-photon detectors, which makes this
protocol feasible with present techniques. By iteration of entanglement
concentration processes, this scheme has a higher efficiency and yield than
those with linear optical elements. All these advantages make this scheme more
efficient and more convenient than others in practical applications.


title: Dark Matter, Modified Gravity and the Mass of the Neutrino

abstract:
  It has been suggested that Einstein's theory of General Relativity can be
modified to accomodate mismatches between the gravitational field and luminous
matter on a wide range of scales. Covariant theories of modified gravity
generically predict the existence of extra degrees of freedom which may be
interpreted as dark matter. We study a subclass of these theories where the
overall energy density in these extra degrees of freedom is subdominant
relative to the baryon density and show that they favour the presence of
massive neutrinos. For some specific cases (such as a flat Universes with a
cosmological constant) one finds a conservative lower bound on the neutrinos
mass of $m_\nu>0.31$ eV.


title:
Effect of magnetic field and temperature on the ferroelectric loop in
  MnWO4

abstract:
  The ferroelectric properties of MnWO4 single crystal have been investigated.
Despite a relatively low remanent polarization, we show that the sample is
ferroelectric. The shape of the ferroelectric loop of MnWO4 strongly depends on
magnetic field and temperature. While its dependence does not directly
correlate with the magnetocapacitance effect before the paraelectric
transition, the effect of magnetic field on the ferroelectric polarization loop
supports magnetoelectric coupling.


title:
The influence of winds on the time-dependent behavior of
  self-gravitating accretion discs

abstract:
  We study effects of winds on the time evolution of isothermal,
self-gravitating accretion discs by adopting a radius dependent mass loss rate
because of the existence of the wind. Our similarity and semi-analytical
solution describes time evolution of the system in the slow accretion limit.
The disc structure is distinct in the inner and outer parts, irrespective of
the existence of the wind. We show that existence of wind will lead to a
reduction of the surface density in the inner and outer parts of the disc in
comparison to a no-wind solution. Also, the radial velocity significantly
increases in the outer part of the disc, however, the accretion rate decreases
due to the reduced surface density in comparison to the no-wind solution. In
the inner part of the disc, mass loss due to the wind is negligible according
to our solution. But the radial size of this no-wind inner region becomes
smaller for stronger winds.


title: Differentiability of stochastic flow of reflected Brownian motions

abstract:
  We prove that a stochastic flow of reflected Brownian motions in a smooth
multidimensional domain is differentiable with respect to its initial position.
The derivative is a linear map represented by a multiplicative functional for
reflected Brownian motion. The method of proof is based on excursion theory and
analysis of the deterministic Skorokhod equation.


title: Security Bounds for Quantum Cryptography with Finite Resources

abstract:
  A practical quantum key distribution (QKD) protocol necessarily runs in
finite time and, hence, only a finite amount of communication is exchanged.
This is in contrast to most of the standard results on the security of QKD,
which only hold in the limit where the number of transmitted signals approaches
infinity. Here, we analyze the security of QKD under the realistic assumption
that the amount of communication is finite. At the level of the general
formalism, we present new results that help simplifying the actual
implementation of QKD protocols: in particular, we show that symmetrization
steps, which are required by certain security proofs (e.g., proofs based on de
Finetti's representation theorem), can be omitted in practical implementations.
Also, we demonstrate how two-way reconciliation protocols can be taken into
account in the security analysis. At the level of numerical estimates, we
present the bounds with finite resources for ``device-independent security''
against collective attacks.


title: The Rosette Eye: the key transition phase in the birth of a massive star

abstract:
  Massive protostars dramatically influence their surroundings via
accretion-induced outflows and intense radiation fields. They evolve rapidly,
the disk and infalling envelope being evaporated and dissipated in $\sim$
10$^5$ years. Consequently, they are very rare and investigating this important
phase of early stellar evolution is extremely difficult. Here we present the
discovery of a key transient phase in the emergence of a massive young star, in
which ultraviolet radiation from the new-born giant has just punctured through
its natal core. The massive young stellar object AFGL 961 II is readily
resolved in the near infrared. Its morphology closely resembles a cat's eye and
is here dubbed as the Rosette Eye. Emerging ionized flows blow out an hourglass
shaped nebula, which, along with the existence of strong near-infrared excess,
suggests the existence of an accretion disk in the perpendicular direction. The
lobes of the hourglass, however, are capped with arcs of static H$_{2}$
emission produced by fluorescence. This study has strong implications for our
understanding of how massive stars embark on their formation.


title: On the degenerated Arnold-Givental conjecture

abstract:
  We present another view dealing with the Arnold-Givental conjecture on a real
symplectic manifold
  $(M, \omega, \tau)$ with nonempty and compact real part $L={\rm Fix}(\tau)$.
For given $\Lambda\in (0, +\infty]$ and $m\in\N\cup\{0\}$ we show the
equivalence of the following two claims: (i)
  $\sharp(L\cap\phi^H_1(L))\ge m$ for any Hamiltonian function $H\in
C_0^\infty([0, 1]\times M)$ with Hofer's norm $\|H\|<\Lambda$; (ii) $\sharp
{\cal P}(H,\tau)\ge m$ for every $H\in C^\infty_0(\R/\Z\times M)$ satisfying
$H(t,x)=H(-t,\tau(x))\;\forall (t,x)\in\mathbb{R}\times M$ and with Hofer's
norm $\|H\|<2\Lambda$, where ${\cal P}(H, \tau)$ is the set of all $1$-periodic
solutions of $\dot{x}(t)=X_{H}(t,x(t))$ satisfying $x(-t)=\tau(x(t))\;\forall
t\in\R$ (which are also called brake orbits sometimes). Suppose that $(M,
\omega)$ is geometrical bounded for some $J\in{\cal J}(M,\omega)$ with
$\tau^\ast J=-J$ and has a rationality index $r_\omega>0$ or
$r_\omega=+\infty$. Using Hofer's method we prove that if the Hamiltonian $H$
in (ii) above has Hofer's norm $\|H\|<r_\omega$ then
$\sharp(L\cap\phi^H_1(L))\ge\sharp {\cal P}_0(H,\tau)\ge {\rm
Cuplength}_{\F}(L)$ for $\F=\Z_2$, and further for $\F=\Z$ if $L$ is
orientable, where ${\cal P}_0(H,\tau)$ consists of all contractible solutions
in ${\cal P}(H,\tau)$.


title: Itinerant Ferromagnetism in layered crystals LaCoOX (X = P, As)

abstract:
  The electronic and magnetic properties of cobalt-based layered oxypnictides,
LaCoOX (X = P, As), are investigated. LaCoOP and LaCoOAs show metallic type
conduction, and the Fermi edge is observed by hard x-ray photoelectron
spectroscopy. Ferromagnetic transitions occur at 43 K for LaCoOP and 66 K for
LaCoOAs. Above the transition temperatures, temperature dependence of the
magnetic susceptibility follows the Curie-Weiss law. X-ray magnetic circular
dichroism (XMCD) is observed at the Co L2,3-edge, but not at the other edges.
The calculated electronic structure shows a spin polarized ground state. These
results indicate that LaCoOX are itinerant ferromagnets and suggest that their
magnetic properties are governed by spin fluctuation.


title:
Creation and annihilation of fluxons in ac-driven semi-annular Josephson
  junction

abstract:
  The dynamical behavior of a fluxon in a semi-annular long Josephson junction
in the presence of an ac-drive is studied. The non-uniformity due to the non
uniform distribution of bias current is investigated. The oscillating potential
is found to increase the depinning current. Finite difference method is used
for numerical analysis and the response of the system to the ac-bias is
studied. The creation and annihilation of fluxon is also demonstrated
numerically for the first, second and third Zero-Field step cases.


title: Spin-glass instability of short-range spherical ferromagnet

abstract:
  In structurally disordered ferromagnets the weak random dipole-dipole
exchange may transform the polydomain state into a spin-glass one. To some
extent the properties of such phase in disordered isotropic ferromagnet can be
qualitatively described by the spherical model with the short-range
ferromagnetic interaction and weak frustrated infinite-range random-bond
exchange. This model is shown to predict that spin-glass phase substitute the
ferromagnetic one at the arbitrary small disorder strength and that its
thermodynamics has some similarity to that of polydomain state along with some
significant distinctions. In particular, the longitudinal susceptibility at
small fields becomes frozen below transition point at a constant value
depending on the disorder strength, while the third order nonlinear magnetic
susceptibilitiy exhibits the temperature oscillations in small field near the
transition point. The relation of these predictions to the experimental data
for some disordered isotropic ferromagnets is discussed.


title: Survival of charmonia above Tc in anisotropic lattice QCD

abstract:
  We find a strong evidence for the survival of $J/\Psi$ and $\eta_c$ as
spatially-localized $c\bar c$ (quasi-)bound states above the QCD critical
temperature $T_c$, by investigating the boundary-condition dependence of their
energies and spectral functions. In a finite-volume box, there arises a
boundary-condition dependence for spatially spread states, while no such
dependence appears for spatially compact states. In lattice QCD, we find almost
{\it no} spatial boundary-condition dependence for the energy of the $c\bar c$
system in $J/\Psi$ and $\eta_c$ channels for $T\simeq(1.11-2.07)T_c$. We also
investigate the spectral function of charmonia above $T_c$ in lattice QCD using
the maximum entropy method (MEM) in terms of the boundary-condition dependence.
There is {\it no} spatial boundary-condition dependence for the low-lying peaks
corresponding to $J/\Psi$ and $\eta_c$ around 3GeV at $1.62T_c$. These facts
indicate the survival of $J/\Psi$ and $\eta_c$ as compact $c\bar c$
(quasi-)bound states for $T_c < T < 2T_c$.


title: Universal Cellular Automata Based on the Collisions of Soft Spheres

abstract:
  Fredkin's Billiard Ball Model (BBM) is a continuous classical mechanical
model of computation based on the elastic collisions of identical
finite-diameter hard spheres. When the BBM is initialized appropriately, the
sequence of states that appear at successive integer time-steps is equivalent
to a discrete digital dynamics. Here we discuss some models of computation that
are based on the elastic collisions of identical finite-diameter soft spheres:
spheres which are very compressible and hence take an appreciable amount of
time to bounce off each other. Because of this extended impact period, these
Soft Sphere Models (SSM's) correspond directly to simple lattice gas
automata--unlike the fast-impact BBM. Successive time-steps of an SSM lattice
gas dynamics can be viewed as integer-time snapshots of a continuous physical
dynamics with a finite-range soft-potential interaction. We present both 2D and
3D models of universal CA's of this type, and then discuss spatially-efficient
computation using momentum conserving versions of these models (i.e., without
fixed mirrors). Finally, we discuss the interpretation of these models as
relativistic and as semi-classical systems, and extensions of these models
motivated by these interpretations.


title: QoS Challenges and Opportunities in Wireless Sensor/Actuator Networks

abstract:
  A wireless sensor/actuator network (WSAN) is a group of sensors and actuators
that are geographically distributed and interconnected by wireless networks.
Sensors gather information about the state of physical world. Actuators react
to this information by performing appropriate actions. WSANs thus enable cyber
systems to monitor and manipulate the behavior of the physical world. WSANs are
growing at a tremendous pace, just like the exploding evolution of Internet.
Supporting quality of service (QoS) will be of critical importance for
pervasive WSANs that serve as the network infrastructure of diverse
applications. To spark new research and development interests in this field,
this paper examines and discusses the requirements, critical challenges, and
open research issues on QoS management in WSANs. A brief overview of recent
progress is given.


title: Symbolic computation of moments of sampling distributions

abstract:
  By means of the notion of umbrae indexed by multisets, a general method to
express estimators and their products in terms of power sums is derived. A
connection between the notion of multiset and integer partition leads
immediately to a way to speed up the procedures. Comparisons of computational
times with known procedures show how this approach turns out to be more
efficient in eliminating much unnecessary computation.


title: Feedback Scheduling of Priority-Driven Control Networks

abstract:
  With traditional open-loop scheduling of network resources, the
quality-of-control (QoC) of networked control systems (NCSs) may degrade
significantly in the presence of limited bandwidth and variable workload. The
goal of this work is to maximize the overall QoC of NCSs through dynamically
allocating available network bandwidth. Based on codesign of control and
scheduling, an integrated feedback scheduler is developed to enable flexible
QoC management in dynamic environments. It encompasses a cascaded feedback
scheduling module for sampling period adjustment and a direct feedback
scheduling module for priority modification. The inherent characteristics of
priority-driven control networks make it feasible to implement the proposed
feedback scheduler in real-world systems. Extensive simulations show that the
proposed approach leads to significant QoC improvement over the traditional
open-loop scheduling scheme under both underloaded and overloaded network
conditions.


title:
Cooperative sequential adsorption with nearest-neighbor exclusion and
  next-nearest neighbor interaction

abstract:
  A model for cooperative sequential adsorption that incorporates
nearest-neighbor exclusion and next-nearest neighbor interaction is presented.
It is analyzed for the case of one-dimensional dimer and two-dimensional
monomer adsorption. Analytic solutions found for certain values of the
interaction strength are used to investigate jamming coverage and temporal
approach to jamming in the one-dimensional case. In two dimensions, the series
expansion of the coverage $\theta(t)$ is presented and employed to provide
estimates for the jamming coverage as a function of interaction strength. These
estimates are supported by Monte Carlo simulation results.


title: Control-theoretic dynamic voltage scaling for embedded controllers

abstract:
  For microprocessors used in real-time embedded systems, minimizing power
consumption is difficult due to the timing constraints. Dynamic voltage scaling
(DVS) has been incorporated into modern microprocessors as a promising
technique for exploring the trade-off between energy consumption and system
performance. However, it remains a challenge to realize the potential of DVS in
unpredictable environments where the system workload cannot be accurately
known. Addressing system-level power-aware design for DVS-enabled embedded
controllers, this paper establishes an analytical model for the DVS system that
encompasses multiple real-time control tasks. From this model, a feedback
control based approach to power management is developed to reduce dynamic power
consumption while achieving good application performance. With this approach,
the unpredictability and variability of task execution times can be attacked.
Thanks to the use of feedback control theory, predictable performance of the
DVS system is achieved, which is favorable to real-time applications. Extensive
simulations are conducted to evaluate the performance of the proposed approach.


title: Strange hadron ratios from quark coalescence at RHIC and LHC

abstract:
  Quark coalescence models have been applied successfully to reproduce measured
hadron production data in relativistic heavy ion collisions at SPS and RHIC
energies, which finding strongly supports the formation of deconfined quark
matter in these collisions. The investigation of meson and baryon production is
an ideal tool to understand dynamical details of hadronization, especially
strange hadron numbers and ratios. We display latest results on the production
of strange particles in quark coalescence processes in heavy ion collisions at
different collider energies.


title:
Fuzzy Logic Control Based QoS Management in Wireless Sensor/Actuator
  Networks

abstract:
  Wireless sensor/actuator networks (WSANs) are emerging rapidly as a new
generation of sensor networks. Despite intensive research in wireless sensor
networks (WSNs), limited work has been found in the open literature in the
field of WSANs. In particular, quality-of-service (QoS) management in WSANs
remains an important issue yet to be investigated. As an attempt in this
direction, this paper develops a fuzzy logic control based QoS management
(FLC-QM) scheme for WSANs with constrained resources and in dynamic and
unpredictable environments. Taking advantage of the feedback control
technology, this scheme deals with the impact of unpredictable changes in
traffic load on the QoS of WSANs. It utilizes a fuzzy logic controller inside
each source sensor node to adapt sampling period to the deadline miss ratio
associated with data transmission from the sensor to the actuator. The deadline
miss ratio is maintained at a pre-determined desired level so that the required
QoS can be achieved. The FLC-QM has the advantages of generality, scalability,
and simplicity. Simulation results show that the FLC-QM can provide WSANs with
QoS support.


title: Critical Accretion Rate for Triggered Star Formation

abstract:
  We have reexamined the similarity solution for a self-gravitating isothermal
gas sphere and examined implication to star formation in a turbulent cloud.
When parameters are adequately chosen, the similarity solution expresses an
accreting isothermal gas sphere bounded by a spherical shock wave. The mass and
radius of the sphere increases in proportion to the time, while the central
density decreases in proportion to the inverse square of time. The similarity
solution is specified by the accretion rate and the infall velocity. The
accretion rate has an upper limit for a given infall velocity. When the
accretion rate is below the upper limit, there exist a pair of similarity
solutions for a given set of the accretion rate and infall velocity. One of
them is confirmed to be unstable against a spherical perturbation. This means
that the gas sphere collapses to initiate star formation only when the
accretion rate is larger than the upper limit. We have also examined stability
of the similarity solution against non-spherical perturbation. Non-spherical
perturbations are found to be damped.


title: On the Adsorption of Two-State Polymers

abstract:
  Monte Carlo(MC) simulations produce evidence that annealed copolymers
incorporating two interconverting monomers, P and H, adsorb as homopolymers
with an effective adsorption energy per monomer, $\epsilon_{eff}$, that depends
on the PH equilibrium constants in the bulk and at the surface. The cross-over
exponent, $\Phi,$ is unmodified. The MC results on the overall PH ratio, the PH
ratio at the surface and in the bulk as well as the number of adsorbed monomers
are in quantitative agreement with this hypothesis and the theoretically
derived $\epsilon_{eff}$. The evidence suggests that the form of surface
potential does not affect $\Phi$ but does influence the PH equilibrium.


title:
Towards Canonical Quantum Gravity for G1 Geometries in 2+1 Dimensions
  with a Lambda--Term

abstract:
  The canonical analysis and subsequent quantization of the (2+1)-dimensional
action of pure gravity plus a cosmological constant term is considered, under
the assumption of the existence of one spacelike Killing vector field. The
proper imposition of the quantum analogues of the two linear (momentum)
constraints reduces an initial collection of state vectors, consisting of all
smooth functionals of the components (and/or their derivatives) of the spatial
metric, to particular scalar smooth functionals. The demand that the
midi-superspace metric (inferred from the kinetic part of the quadratic
(Hamiltonian) constraint) must define on the space of these states an induced
metric whose components are given in terms of the same states, which is made
possible through an appropriate re-normalization assumption, severely reduces
the possible state vectors to three unique (up to general coordinate
transformations) smooth scalar functionals. The quantum analogue of the
Hamiltonian constraint produces a Wheeler-DeWitt equation based on this reduced
manifold of states, which is completely integrated.


title:
Influence of salt and viral protein charge distribution on encapsidation
  of single-stranded viral RNA molecules

abstract:
  We examine the limits on viral composition that are set by the electrostatic
interactions effected by the charge on the viral proteins, the single-stranded
viral RNA molecule and monovalent salt ions in the solution. Within the
mean-field model of viral energetics we demonstrate the prime importance of the
salt concentration for the assembly of a virus. We find that the encapsidation
of the viral RNA molecule is thermodynamically suppressed in solutions with
high concentrations of monovalent salt. This effect is significantly less
important in viruses with proteins whose charge distribution protrudes into the
interior of the capsid, leading to an increase in the stability of such viruses
in solutions with high salt concentrations. The delocalization of positive
charge on the capsid protein arms thus profoundly increases reliability of
viral assembly in high-salt solutions.


title:
Zener Tunneling in Semiconducting Nanotube and Graphene Nanoribbon p-n
  Junctions

abstract:
  A theory is developed for interband tunneling in semiconducting carbon
nanotube and graphene nanoribbon p-n junction diodes. Characteristic length and
energy scales that dictate the tunneling probabilities and currents are
evaluated. By comparing the Zener tunneling processes in these structures to
traditional group IV and III-V semiconductors, it is proved that for identical
bandgaps, carbon based 1D structures have higher tunneling probabilities. The
high tunneling current magnitudes for 1D carbon structures suggest the distinct
feasibility of high-performance tunneling-based field-effect transistors.


title:
Endohedral resonances: modification of atomic photoionization by the
  fullerenes shell

abstract:
  We discuss the complicated resonance structure of the endohedral atom
photoionization cross section. Very strong enhancement and interference
patterns in the photoionization cross-section of the valent and subvalent
subshells of noble gas endohedral atoms A@C60 are demonstrated. It is shown
also that the atomic Giant resonance can be either completely destroyed or
remains almost untouched depending on the velocity of photoelectrons that are
emitted in the resonance's decay process. These effects are results of dynamic
modification of the incoming beam of radiation due to polarization of the
fullerenes electron shell and reflection of photoelectrons be the fullerenes
shell static potential. We have considered the outer np- and subvalent
ns-subshells for Ne, Ar, Kr and Xe noble gas atoms. The modification of the
Giant resonances is considered for a whole sequence of endohedrals with atoms
and ions Xe, Ba, La, Ce+, Ce+4, Eu. The polarization of the fullerene shell is
expressed via the total photoabsorption cross section. The photoelectron
reflection from the static potential is taken into account in the frame of the
so-called bubble potential that is a spherical -type potential.


title: Quantum induced w = -1 crossing of the quintessence and phantom models

abstract:
  Considering the single scalar field models of dark energy, i.e. the
quintessence and phantom models, it is shown that the quantum effects can cause
the system crosses the w = -1 line. This phenomenon does not occur in classical
level. The quantum effects are described via the account of conformal anomaly.


title: Regularization of Invers Problem for M-Ary Channel

abstract:
  The problem of computation of parameters of m-ary channel is considered. It
is demonstrated that although the problem is ill-posed, it is possible turning
of the parameters of the system and transform the problem to well-posed one.


title:
Recall a Prediction on J/psi Nuclear Modification Factor for STAR
  Measurements

abstract:
  STAR collaboration has offered eminent nuclear modification factor of J/psi
at high p_T and midrapidity produced in Cu-Cu collisions at \sqrt {s_{NN}}= 200
GeV. Recalling a prediction we can understand that the feature of high-p_T
nuclear modification factor is related to c\bar c produced by 2-to-1 and 2-to-2
partonic processes in deconfined matter particularly in the prethermal stage
and to the recombination of c and \bar c. The nuclear modification factor at
high p_T is sensitive to the earliest form of deconfined matter that does not
have a temperature.


title:
3-d resistive MHD simulations of magnetic reconnection and the tearing
  mode instability in current sheets

abstract:
  Magnetic reconnection plays a critical role in many astrophysical processes
where high energy emission is observed, e.g. particle acceleration,
relativistic accretion powered outflows, pulsar winds and probably in
dissipation of Poynting flux in GRBs. The magnetic field acts as a reservoir of
energy and can dissipate its energy to thermal and kinetic energy via the
tearing mode instability. We have performed 3d nonlinear MHD simulations of the
tearing mode instability in a current sheet. Results from a temporal stability
analysis in both the linear regime and weakly nonlinear (Rutherford) regime are
compared to the numerical simulations. We observe magnetic island formation,
island merging and oscillation once the instability has saturated. The growth
in the linear regime is exponential in agreement with linear theory. In the
second, Rutherford regime the island width grows linearly with time. We find
that thermal energy produced in the current sheet strongly dominates the
kinetic energy. Finally preliminary analysis indicates a P(k) 4.8 power law for
the power spectral density which suggests that the tearing mode vortices play a
role in setting up an energy cascade.


title: Lasso-type recovery of sparse representations for high-dimensional data

abstract:
  The Lasso is an attractive technique for regularization and variable
selection for high-dimensional data, where the number of predictor variables
$p_n$ is potentially much larger than the number of samples $n$. However, it
was recently discovered that the sparsity pattern of the Lasso estimator can
only be asymptotically identical to the true sparsity pattern if the design
matrix satisfies the so-called irrepresentable condition. The latter condition
can easily be violated in the presence of highly correlated variables. Here we
examine the behavior of the Lasso estimators if the irrepresentable condition
is relaxed. Even though the Lasso cannot recover the correct sparsity pattern,
we show that the estimator is still consistent in the $\ell_2$-norm sense for
fixed designs under conditions on (a) the number $s_n$ of nonzero components of
the vector $\beta_n$ and (b) the minimal singular values of design matrices
that are induced by selecting small subsets of variables. Furthermore, a rate
of convergence result is obtained on the $\ell_2$ error with an appropriate
choice of the smoothing parameter. The rate is shown to be optimal under the
condition of bounded maximal and minimal sparse eigenvalues. Our results imply
that, with high probability, all important variables are selected. The set of
selected variables is a meaningful reduction on the original set of variables.
Finally, our results are illustrated with the detection of closely adjacent
frequencies, a problem encountered in astrophysics.


title:
Dynamics of meromorphic maps with small topological degree III:
  geometric currents and ergodic theory

abstract:
  We continue our study of the dynamics of mappings with small topological
degree on (projective) complex surfaces. Previously, under mild hypotheses, we
have constructed an ergodic ``equilibrium'' measure for each such mapping. Here
we study the dynamical properties of this measure in detail: we give optimal
bounds for its Lyapunov exponents, prove that it has maximal entropy, and show
that it has product structure in the natural extension. Under a natural further
assumption, we show that saddle points are equidistributed towards this
measure. This generalize results that were known in the invertible case and is,
to our knowledge, one among not very many instances in which a natural
invariant measure for a non-invertible dynamical system is well-understood.


title:
Anomalous frequency and intensity scaling of collective and local modes
  in a coupled spin tetrahedron system

abstract:
  We report on the magnetic excitation spectrum of the coupled spin tetrahedral
system Cu$_{2}$Te$_{2}$O$_{5}$Cl$_{2}$ using Raman scattering on single
crystals. The transition to an ordered state at T$_{N}^{Cl}$=18.2 K evidenced
from thermodynamic data leads to the evolution of distinct low-energy magnetic
excitations superimposed by a broad maximum. These modes are ascribed to
magnons with different degree of localization and a two-magnon continuum. Two
of the modes develop a substantial energy shift with decreasing temperature
similar to the order parameter of other Neel ordered systems. The other two
modes show only a negligible temperature dependence and dissolve above the
ordering temperature in a continuum of excitations at finite energies. These
observations point to a delicate interplay of magnetic inter- and
intra-tetrahedra degrees of freedom and an importance of singlet fluctuations
in describing a spin dynamics.


title:
Proposal for geometric generation of a biexciton in a quantum dot using
  a chirped pulse

abstract:
  We propose to create a biexciton by a coherent optical process using a
frequency-sweeping (chirped) laser pulse. In contrast to the two-photon Rabi
flop scheme, the present method uses the state transfer through avoided level
crossing and is a geometric control. The proposed process is robust against
pulse area uncertainty, detuning, and dephasing. The speed of the adiabatic
operation is constrained by the biexciton binding energy.


title: Burgers' equation in 2D SU(N) YM

abstract:
  It is shown that the logarithmic derivative of the characteristic polynomial
of a Wilson loop in two dimensional pure Yang Mills theory with gauge group
SU(N) exactly satisfies Burgers' equation, with viscosity given by 1/(2N). The
Wilson loop does not intersect itself and Euclidean space-time is assumed flat
and infinite. This result provides a precise framework in 2D YM for recent
observations of Blaizot and Nowak and was inspired by their work.


title: Fun With Fourier Series

abstract:
  By using computers to do experimental manipulations on Fourier series, we
construct additional series with interesting properties. For example, we
construct several series whose sums remain unchanged when the nth term is
multiplied by sin(n)/n. One series with this property is this classic series
for pi/4: pi/4 = 1 - 1/3 + 1/5 ... = 1*(sin(1)/1) - (1/3)*(sin(3)/3) +
(1/5)*(sin(5)/5).... Another example is sum (n = 1 to infinity) of (sin(n)/n) =
sum (n = 1 to infinity) of (sin(n)/n)^2 = (pi - 1)/2. This material should be
accessible to undergraduates. This paper also includes a Mathematica package
that makes it easy to calculate and graph the Fourier series of many types of
functions.


title: Repeated Interaction Quantum Systems: Deterministic and Random

abstract:
  This paper gives an overview of recent results concerning the long time
dynamics of repeated interaction quantum systems in a deterministic and random
framework. We describe the non equilibrium steady states (NESS) such systems
display and we present, as a macroscopic consequence, a second law of
thermodynamics these NESS give rise to. We also explain in some details the
analysis of products of certain random matrices underlying this dynamical
problem.


title: On the spectra of scalar mesons from HQCD models

abstract:
  We determine the holographic spectra of scalar mesons from the fluctuations
of the embedding of flavor D-brane probes in HQCD models. The models we
consider include a generalization of the Sakai Sugimoto model at zero
temperature and at the "high-temperature intermediate phase", where the system
is in a deconfining phase while admitting chiral symmetry breaking and a
non-critical 6d model at zero temperature. All these models are based on
backgrounds associated with near extremal N_c D4 branes and a set of N_f<<N_c
flavor probe branes that admit geometrical chiral symmetry breaking. We point
out that the spectra of these models include a 0^{--} branch which does not
show up in nature.
  At zero temperature we found that the masses of the mesons M_n depend on the
"constituent quark mass" parameter m^c_q and on the excitation number n as
M_n^2 m^c_q and M^2_n n^{1.7} for the ten dimensional case and as M_n m^c_q and
M_n n^{0.75} in the non-critical case. At the high temperature intermediate
phase we detect a decrease of the masses of low spin mesons as a function of
the temperature similar to holographic vector mesons and to lattice
calculations.


title: Chronological spacetimes without lightlike lines are stably causal

abstract:
  The statement of the title is proved. It implies that under physically
reasonable conditions, spacetimes which are free from singularities are
necessarily stably causal and hence admit a time function. Read as a
singularity theorem it states that if there is some form of causality violation
on spacetime then either it is the worst possible, namely violation of
chronology, or there is a singularity. The analogous result: "Non-totally
vicious spacetimes without lightlike rays are globally hyperbolic" is also
proved, and its physical consequences are explored.


title: Superlinear Amplitude Amplification

abstract:
  Quantum search/amplitude amplification algorithms are designed to be able to
amplify the amplitude in the target state linearly with the number of
operations. Since the probability is the square of the amplitude, this results
in the success probability rising quadratically with the number of operations.
This paper presents a new kind of quantum search algorithm in which the
amplitude of the target state, itself increases quadratically with the number
of operations. However, the domain of applications of this is much more limited
than standard amplitude amplification.


title: Formation of Non-Abelian Monopoles Connected by Strings

abstract:
  We study the formation of monopoles and strings in a model where SU(3) is
spontaneously broken to U(2)=[SU(2)\times U(1)]/\ZZ_2, and then to U(1). The
first symmetry breaking generates monopoles with both SU(2) and U(1) charges
since the vacuum manifold is \CC P^2. To study the formation of these
monopoles, we explicitly describe an algorithm to detect topologically
non-trivial mappings on \CC P^2. The second symmetry breaking creates \ZZ_2
strings linking either monopole-monopole pairs or monopole-antimonopole pairs.
When the strings pull the monopoles together they may create stable monopoles
of charge 2 or else annihilate. We determine the length distribution of strings
and the fraction of monopoles that will survive after the second symmetry
breaking. Possible implications for topological defects produced from the
spontaneous breaking of even larger symmetry groups, as in Grand Unified
models, are discussed.


title: Some properties of non-positively curved lattices

abstract:
  We announce results on the structure of CAT(0) groups, CAT(0) lattices and of
the underlying spaces. Our statements rely notably on a general study of the
full isometry groups of proper CAT(0) spaces. Classical statements about
Hadamard manifolds are established for singular spaces; new arithmeticity and
rigidity statements are obtained.


title: Even Walks and Estimates of High Moments of Large Wigner Random Matrices

abstract:
  We revisit the problem of estimates of moments of random n-dimensional
matrices of Wigner ensemble by using the approach elaborated by Ya. Sinai and
A. Soshnikov and further developed by A. Ruzmaikina. Our main subject is given
by the structure of closed even walks and their graphs that arise in these
studies. We show that the total degree of a vertex of such a graph depends not
only on the self-intersections degree of but also on the total number of all
non-closed instants of self-intersections of the walk. This result is used to
fill the gaps of earlier considerations.


title: Marking (1,2) Points of the Brownian Web and Applications

abstract:
  The Brownian web (BW), which developed from the work of Arratia and then
T\'{o}th and Werner, is a random collection of paths (with specified starting
points) in one plus one dimensional space-time that arises as the scaling limit
of the discrete web (DW) of coalescing simple random walks. Two recently
introduced extensions of the BW, the Brownian net (BN) constructed by Sun and
Swart, and the dynamical Brownian web (DyBW) proposed by Howitt and Warren, are
(or should be) scaling limits of corresponding discrete extensions of the DW --
the discrete net (DN) and the dynamical discrete web (DyDW). These discrete
extensions have a natural geometric structure in which the underlying Bernoulli
left or right "arrow" structure of the DW is extended by means of branching
(i.e., allowing left and right simultaneously) to construct the DN or by means
of switching (i.e., from left to right and vice-versa) to construct the DyDW.
In this paper we show that there is a similar structure in the continuum where
arrow direction is replaced by the left or right parity of the (1,2) space-time
points of the BW (points with one incoming path from the past and two outgoing
paths to the future, only one of which is a continuation of the incoming path).
We then provide a complete construction of the DyBW and an alternate
construction of the BN to that of Sun and Swart by proving that the switching
or branching can be implemented by a Poissonian marking of the (1,2) points.


title: Connected components of partition preserving diffeomorphisms

abstract:
  Let $f:\mathbb{R}^2 \to \mathbb{R}$ be a real homogeneous polynomial and
$S(f)$ be the group of diffeomorphisms $h:\mathbb{R}^2 \to \mathbb{R}^2$
preserving $f$, i.e. $f \circ h = f$. Denote by $S(f,r)$, $(0\leq r \leq
\infty)$, the identity path component of $S(f)$ with respect to the weak
Whitney $C^{r}_{W}$-topology. We prove that $S(f,\infty) = \cdots = S(f,1)$ for
all such $f$ and that $S(f,1) \not= S(f,0)$ if and only if $f$ is a product of
at least two distinct irreducible over $\mathbb{R}$ quadratic forms.


title:
Comment on ``Success of collinear expansion in the calculation of
  induced gluon emission''

abstract:
  We show that the arguments against our recent paper on the failure of the
collinear expansion in the calculation of the induced gluon emission raised by
X.N. Wang are either incorrect or irrelevant.


title:
Modulational instability of optical beams in photorefractive media in
  the presence of two wave and four wave mixing effects

abstract:
  Modulational instability in a photorefractive medium is studied in the
presence of two wave mixing. We then propose and derive a model for forward
four wave mixing in the photorefractive medium and investigate the modulational
instability induced by four wave mixing effects. By using the standard linear
stability analysis the instability gain is obtained. In both the cases, the
geometry is such that the effect of self-phase-modulation self-focusing is
suppressed and only the holographic focusing nonlinearity is acting.


title:
Generalized inverses and polar decomposition of unbounded regular
  operators on Hilbert $C^*$-modules

abstract:
  In this note we show that an unbounded regular operator $t$ on Hilbert
$C^*$-modules over an arbitrary $C^*$ algebra $ \mathcal{A}$ has polar
decomposition if and only if the closures of the ranges of $t$ and $|t|$ are
orthogonally complemented, if and only if the operators $t$ and $t^*$ have
unbounded regular generalized inverses. For a given $C^*$-algebra $
\mathcal{A}$ any densely defined $\mathcal A$-linear closed operator $t$
between Hilbert $C^*$-modules has polar decomposition, if and only if any
densely defined $\mathcal A$-linear closed operator $t$ between Hilbert
$C^*$-modules has generalized inverse, if and only if $\mathcal A$ is a
$C^*$-algebra of compact operators.


title:
Interpreting the Variability of Double-Peaked Emission Lines in Active
  Galactic Nuclei with Stochastically Perturbed Accretion Disk Models

abstract:
  In an effort to explain the short-timescale variability of the broad,
double-peaked profiles of some active galactic nuclei, we constructed
stochastically perturbed accretion disk models and calculated H alpha line
profile series as the bright spots rotate, shear and decay. We determined the
dependence of the properties of the line profile variability on the spot
properties. We compared the variability of the line profile from the models to
the observed variability of the H alpha line of Arp 102B and 3C 390.3. We find
that spots need to be concentrated in the outer parts of the line emitting
region to reproduce the observed variability properties for Arp 102B. This
rules out spot production by star/disk collisions and favors a scenario where
the radius of marginal self-gravity is within the line emitting region,
creating a sharp increase in the radial spot distribution in the outer parts.
In the case of 3C 390.3, all the families of models that we tested can
reproduce the observed variability for a suitable choice of model parameters.


title: Operating an atom interferometer beyond its linear range

abstract:
  In this paper, we show that an atom interferometer inertial sensor, when
associated to the auxiliary measurement of external vibrations, can be operated
beyond its linear range and still keep a high acceleration sensitivity. We
propose and compare two measurement procedures (fringe fitting and nonlinear
lock) that can be used to extract the mean phase of the interferometer when the
interferometer phase fluctuations exceed $2\pi$. Despite operating in the urban
environment of inner Paris without any vibration isolation, the use of a low
noise seismometer for the measurement of ground vibrations allows our atom
gravimeter to reach at night a sensitivity as good as $5.5\times10^{-8}$g at 1
s. Robustness of the measurement to large vibration noise is also demonstrated
by the ability of our gravimeter to operate during an earthquake with excellent
sensitivity. Our high repetition rate allows for recovering the true low
frequency seismic vibrations, ensuring proper averaging. Such techniques open
new perspectives for applications in other fields, such as navigation and
geophysics.


title: Attoscience

abstract:
  Fascinating developments in optical pulse engineering over the last 20 years
lead to the generation of laser pulses as short as few femtosecond, providing a
unique tool for high resolution time domain spectroscopy. However, a number of
the processes in nature evolve with characteristic times of the order of 1 fs
or even shorter. Time domain studies of such processes require at first place
sub-fs resolution, offered by pulse depicting attosecond localization. The
generation, characterization and proof of principle applications of such pulses
is the target of the attoscience.


title:
Preparation and detection of d-wave superfluidity in two-dimensional
  optical superlattices

abstract:
  We propose a controlled method to create and detect d-wave superfluidity with
ultracold fermionic atoms loaded in two-dimensional optical superlattices. Our
scheme consists in preparing an array of nearest-neighbor coupled square
plaquettes or ``superplaquettes'' and using them as building blocks to
construct a d-wave superfluid state. We describe how to use the coherent
dynamical evolution in such a system to experimentally probe the pairing
mechanism. We also derive the zero temperature phase diagram of the fermions in
a checkerboard lattice (many weakly coupled plaquettes) and show that by tuning
the inter-plaquette tunneling spin-dependently or varying the filling factor
one can drive the system into a d-wave superfluid phase or a Cooper pair
density wave phase. We discuss the use of noise correlation measurements to
experimentally probe these phases.