title: Nonexpansive iterations in uniformly convex $W$-hyperbolic spaces

abstract:
  We propose the class of uniformly convex $W$-hyperbolic spaces with monotone
modulus of uniform convexity ($UCW$-hyperbolic spaces for short) as an
appropriate setting for the study of nonexpansive iterations. $UCW$-hyperbolic
spaces are a natural generalization both of uniformly convex normed spaces and
CAT(0)-spaces. Furthermore, we apply proof mining techniques to get effective
rates of asymptotic regularity for Ishikawa iterations of nonexpansive
self-mappings of closed convex subsets in $UCW$-hyperbolic spaces. These
effective results are new even for uniformly convex Banach spaces.


title: Beyond networks: Opinion formation in triplet-based populations

abstract:
  We study a process of opinion formation in a population of agents whose
interaction pattern is defined on the basis of randomly distributed groups of
three agents, or triplets -in contrast to networks, which are defined on the
basis of agent pairs. Results for the time needed to reach full consensus are
compared between a triplet-based structure with a given number of triplets and
a random network with the same number of triangles. The full-consensus time in
the triplet structure is systematically lower than in the network. This
discrepancy can be ascribed to differences in the shape of the probability
distribution for the number of triplets and triangles per agent in each
interaction pattern.


title: Master-equation analysis of accelerating networks

abstract:
  In many real-world networks, the rates of node and link addition are time
dependent. This observation motivates the definition of accelerating networks.
There has been relatively little investigation of accelerating networks and
previous efforts at analyzing their degree distributions have employed
mean-field techniques. By contrast, we show that it is possible to apply a
master-equation approach to such network development. We provide full
time-dependent expressions for the evolution of the degree distributions for
the canonical situations of random and preferential attachment in networks
undergoing constant acceleration. These results are in excellent agreement with
results obtained from simulations. We note that a growing, non-equilibrium
network undergoing constant acceleration with random attachment is equivalent
to a classical random graph, bridging the gap between non-equilibrium and
classical equilibrium networks.


title: Algebraic properties of edge ideals via combinatorial topology

abstract:
  We apply some basic notions from combinatorial topology to establish various
algebraic properties of edge ideals of graphs and more general Stanley-Reisner
rings. In this way we provide new short proofs of some theorems from the
literature regarding linearity, Betti numbers, and (sequentially)
Cohen-Macaulay properties of edges ideals associated to chordal, complements of
chordal, and Ferrers graphs, as well as trees and forests. Our approach unifies
(and in many cases strengthens) these results and also provides
combinatorial/enumerative interpretations of certain algebraic properties. We
apply our setup to obtain new results regarding algebraic properties of edge
ideals in the context of local changes to a graph (adding whiskers and ears) as
well as bounded vertex degree. These methods also lead to recursive relations
among certain generating functions of Betti numbers which we use to establish
new formulas for the projective dimension of edge ideals. We use only
well-known tools from combinatorial topology along the lines of independence
complexes of graphs, (not necessarily pure) vertex decomposability,
shellability, etc.


title:
Checking formalism for central exclusive production in the first LHC
  runs

abstract:
  We discuss how the early LHC data runs can provide crucial tests of the
formalism used to predict the cross sections of central exclusive production.


title: Counting integral points on universal torsors

abstract:
  Manin's conjecture for the asymptotic behavior of the number of rational
points of bounded height on del Pezzo surfaces can be approached through
universal torsors. We prove several auxiliary results for the estimation of the
number of integral points in certain regions on universal torsors. As an
application, we prove Manin's conjecture for a singular quartic del Pezzo
surface.


title: The Donaldson equation

abstract:
  In this short note, we solve a Dirichlet problem for a fully nonlinear
elliptic equation. The operator is introduced by S. Donaldson and it is
relevant to the geometry of the space of volume forms.


title: Interferometric and seismic constraints on the roAp star alpha Cir

abstract:
  We present new constraints on the rapidly oscillating Ap star alpha Cir,
derived from a combination of interferometric and photometric data obtained
with the Sydney University Stellar Interferometer (SUSI) and the WIRE
satellite. The highlights of our study are:
  1. The first determination of the angular diameter of an roAp star.
  2. A nearly model-independent determination of the effective temperature of
alpha Cir, which is found to be lower than previously estimated values.
  3. Detection of two new oscillation frequencies allowing a determination of
the large separation of alpha Cir.
  Based on this new information, we have computed non-magnetic and magnetic
models for alpha Cir. We show that the value of the observed large separation
found from the new data agrees well with that derived from theoretical models.
Moreover, we also show how the magnetic field may explain some of the anomalies
seen in the oscillation spectrum and how these in turn provide constraints on
the magnitude and topology of the magnetic field.


title:
Vortex Penetration into a Type II Superconductor due to a Mesoscopic
  External Current

abstract:
  Applying the London theory we study curved vortices produced by an external
current near and parallel to the surface of a type II superconductor. By
minimizing the energy functional we find the contour describing the hard core
of the flux line, and predict the threshold current for entrance of the first
vortex. We assume that the vortex entrance is allowed due to surface defects,
despite the Bean-Livingston barrier. Compared to the usual situation with a
homogeneous magnetic field, the main effect of the present geometry is that
larger magnetic fields can be applied locally before vortices enter the
superconducting sample. It is argued that this effect can be further enhanced
in anisotropic superconductors.


title: D-state effects in the electromagnetic N-Delta transition

abstract:
  We consider here a manifestly covariant quark model of the nucleon and the
Delta, where one quark is off-shell and the other two quarks form an on-shell
diquark pair. Using this model, we have shown previously that the nucleon form
factors and the dominant form factor for the gamma N -> Delta transition (the
magnetic dipole (M1) form factor) can be well described by nucleon and Delta
wave functions with S-state components only. In this paper we show that
non-vanishing results for the small electric (E2) and Coulomb (C2) quadrupole
form factors can be obtained if D-state components are added to the Delta
valence quark wave function. We present a covariant definition of these
components and compute their contributions to the form factors. We find that
these components cannot, by themselves, describe the data. Explicit pion cloud
contributions must also be added and these contributions dominate both the E2
and the C2 form factors. By parametrizing the pion cloud contribution for the
transition electric and Coulomb form factors in terms of the neutron electric
form factor, we estimate that the contributions of the Delta D-state coupled to
quark core spin of 3/2 is of the order of 1%, and the contributions of the
Delta D-state coupled to quark core spin 1/2 is of the order of 4%.


title: On the short string limit of the folded spinning string in AdS5 x S5

abstract:
  In this paper we generalize the results of arXiv:0806.4758 to non-zero value
J of angular momentum in S^5. We compute the 1-loop correction to the energy of
the folded spinning string in AdS_5 x S^5 in the particular limit of slow short
string approximation. In this limit the string is moving in a near-flat central
region of AdS_5 slowly rotating in both AdS_5 and S^5. The one-loop correction
should represent the first subleading correction to strong coupling expansion
of the anomalous dimension of short gauge theory operators of the form Tr D^S
Z^J in the SL(2) sector.


title: Study of the mixed Ising spins (1/2,3/2) in a random crystal field

abstract:
  We study the magnetic properties of a mixed Ising ferrimagnetic system, in
which the two interacting sublattices have spins $\sigma$, $(\pm 1/2)$ and
spins $S$, $(\pm 3/2,\pm 1/2)$ in the presence of a random crystal field, with
the mean field approach. The obtained results show the existence of some
interesting phenomena, such as the appearance of a new ferrimagnetic phase
namely the partly ferrimagnetic phase $(m_{\sigma}=\frac{-1}{2},m_S=+1)$ and
consequently the existence of three topologically different types of phase
diagrams. The effect of increasing the exchange interaction parameter $J$, at
very low temperature is investigated. The transitions shown in these phase
diagrams are in good agreement with those obtained in the ground state case.


title: The cohomology of line bundles of splice-quotient singularities

abstract:
  We provide several results on splice-quotient singularities: a combinatorial
expression of the dimension of the first cohomology of all `natural' line
bundles, an equivariant Campillo-Delgado-Gusein-Zade type formula about the
dimension of relative sections of line bundles (proving that the equivariant,
divisorial multi-variable Hilbert series is topological), a combinatorial
description of divisors of analytic function-germs, and an expression for the
multiplicity of the singularity from its resolution graph.
  Additional, we establish a new formula for the Seiberg-Witten invariants of
any rational homology sphere singularity link.


title:
Stability and asymptotic behavior of periodic traveling wave solutions
  of viscous conservation laws in several dimensions

abstract:
  Under natural spectral stability assumptions motivated by previous
investigations of the associated spectral stability problem, we determine sharp
$L^p$ estimates on the linearized solution operator about a multidimensional
planar periodic wave of a system of conservation laws with viscosity, yielding
linearized $L^1\cap L^p\to L^p$ stability for all $p \ge 2$ and dimensions $d
\ge 1$ and nonlinear $L^1\cap H^s\to L^p\cap H^s$ stability and
$L^2$-asymptotic behavior for $p\ge 2$ and $d\ge 3$. The behavior can in
general be rather complicated, involving both convective (i.e., wave-like) and
diffusive effects.


title: Melting Instantons, Domain Walls, and Large N

abstract:
  Monte Carlo studies of $CP^{N-1}$ sigma models have shown that the structure
of topological charge in these models undergoes a sharp transition at
$N=N_c\approx 4$. For $N<N_c$ topological charge is dominated by small
instantons, while for $N>N_c$ it is dominated by extended, thin,
1-dimensionally coherent membranes of topological charge, which can be
interpreted as domain walls between discrete quasi-stable vacua. These vacua
differ by a unit of background electric flux. The transition can be identified
as the delocalization of topological charge, or "instanton melting," a
phenomenon first suggested by Witten to resolve the conflict between instantons
and large $N$ behavior. Implications for $QCD$ are discussed.


title: Neutrino Oscillations and Decoherence

abstract:
  We present an expression for the transition probability between Dirac or
Majorana neutrino flavors obtained from first principles within quantum field
theory. Our derivation is based on a standard quantum mechanical setup and
includes the specific mechanism of neutrino production only in as much as it
specifies the initial state. Our expression for the transition probability
reproduces the usual formula in the plane wave limit and shows the correct
non-relativistic and ultra-relativistic behaviors. It also allows a simple
understanding of the decoherence of the oscillations and of the question of the
arrival times of the different neutrino mass eigenstates. We show numerical
examples for the case of two neutrino generations.


title: The CMS Level-1 Trigger at LHC and Super-LHC

abstract:
  The Level-1 trigger of the CMS experiment at CERN has been designed to select
proton-proton interactions whose final state includes signatures of new physics
in the form of high transverse energy electrons, photons, jets, or high missing
transverse energy. The Level-1 trigger system process data in a pipeline
fashion at a rate of 40 MHz, has a design latency of 128 bunch crossings and an
output rate of 100 KHz. The design of this system is presented with emphasis on
the calorimeter triggers. After a long period of testing and validation of its
performance the Level-1 trigger system has been installed and commissioned at
the CMS experiment at CERN. Cosmic ray data and Monte Carlo events have been
used to compare the actual performance of the trigger with expectations from
off-line emulation models. Results from these studies are presented here. The
limitations of this system to cope with future luminosity upgrades of the LHC,
the Super-LHC, are discussed. The current CMS plan for a new CMS Level-1
trigger system at the Super-LHC is presented. The center point of the new
system is a Level-1 tracking trigger which uses data from a new CMS silicon
tracking detector.


title:
The Best Constant, the Nonexistence of Extremal Functions and Related
  Results for an Improved Hardy-Sobolev Inequality

abstract:
  We present the best constant and the existence of extremal functions for an
Improved Hardy-Sobolev inequality. We prove that, under a proper
transformation, this inequality is equivalent to the Sobolev inequality in
$\mathbb{R}^N$. We also discuss the connection of the related functional spaces
and as a result we obtain some Caffarelli - Kohn - Nirenberg inequalities. Our
starting point is the existence of a minimizer for the Bliss' inequality and
the indirect dependence of the Hardy inequality at the origin.


title: Polarization Patterns in Pulsar Radio Emission

abstract:
  A variety of intriguing polarization patterns are created when polarization
observations of the single pulses from radio pulsars are displayed in a
two-dimensional projection of the Poincare sphere. In many pulsars, the
projections produce two clusters of data points that reside at antipodal points
on the sphere. The clusters are formed by fluctuations in polarization
amplitude that are parallel to the unit vectors representing the polarization
states of the wave propagation modes in the pulsar magnetosphere. In other
pulsars, however, the patterns are more complex, resembling annuli and bow ties
or bars. The formation of these complex patterns is not understood and largely
unexplored. An empirical model of pulsar polarization is used to show that
these patterns arise from polarization fluctuations that are perpendicular to
the mode vectors. The model also shows that the modulation index of the
polarization amplitude is an indicator of polarization pattern complexity. A
stochastic version of generalized Faraday rotation can cause the orientation of
the polarization vectors to fluctuate and is a possible candidate for the
perpendicular fluctuations incorporated in the model. Alternative models
indicate that one mode experiences perpendicular fluctuations and the other
does not, suggesting that the fluctuations could also be due to a
mode-selective random process, such as scattering in the magnetosphere. A
polarization stability analysis of the patterns implies that processes
intrinsic to the emission are more effective in depolarizing the emission than
fluctuations in the orientation of its polarization vector.


title: The Classical Exchange Algebra of AdS5 x S5 String Theory

abstract:
  The classical exchange algebra satisfied by the monodromy matrix of AdS5 x S5
string theory in the Green-Schwarz formulation is determined by using a
first-order Hamiltonian formulation and by adding to the Bena-Polchinski-Roiban
Lax connection terms proportional to constraints. This enables in particular to
show that the conserved charges of this theory are in involution. This result
is obtained for a general world-sheet metric. The same exchange algebra is
obtained within the pure spinor description of AdS5 x S5 string theory. These
results are compared to the one obtained by A. Mikhailov and S. Schaefer-Nameki
for the pure spinor formulation.


title:
Obstructions to the existence of monotone Lagrangian embeddings into
  cotangent bundles of manifolds fibered over the circle

abstract:
  We extend constructions and results of Damian to get topological obstructions
to the existence of closed monotone Lagrangian embeddings into the cotangent
bundle of a space which is the total space of a fibration over the circle.


title: Leptoquarks and Neutrino Masses at the LHC

abstract:
  The properties of light leptoquarks predicted in the context of a simple
grand unified theory and their observability at the LHC are investigated. The
SU(5) symmetry of the theory implies that the leptoquark couplings to matter
are related to the neutrino mass matrix. We study the resulting connection
between neutrino masses and mixing parameters and the leptoquark decays, and
show that different light neutrino hierarchies imply distinctive leptoquark
decay signatures. We also discuss low-energy constraints implied by searches
for charged lepton flavour violation, studies of meson decays, and electroweak
precision data. We perform a detailed parton-level study of the leptoquark
signals and the Standard Model backgrounds at the LHC. With the clean final
states containing a di-lepton plus two jets, the QCD production of the
leptoquark pair can be observed for a leptoquark mass of one TeV and beyond. By
examining the lepton flavor structure of the observed events, one could further
test the model predictions related to the neutrino mass spectrum. In
particular, b-flavor tagging will be useful in distinguishing the neutrino mass
pattern and possibly probing an unknown Majorana phase in the Inverted
Hierarchy or the Quasi-Degenerate scenario. Electroweak associated production
of the leptoquark doublet can also be useful in identifying the quantum numbers
of the leptoquarks and distinguishing between the neutrino mass spectra, even
though the corresponding event rates are smaller than for QCD production. We
find that with only the clean channel of mu+ E_T jets, one could expect an
observable signal for a leptoquark masses of about 600 GeV or higher.


title: Coarse-grained models of complex fluids at equilibrium and unter shear

abstract:
  Complex fluids exhibit structure on a wide range of length and time scales,
and hierarchical approaches are necessary to investigate all facets of their
often unusual properties. The study of idealized coarse-grained models at
different levels of coarse-graining can provide insight into generic structures
and basic dynamical processes at equilibrium and non-equilibrium.
  In the first part of this lecture, some popular coarse-grained models for
membranes and membrane systems are reviewed. Special focus is given to
bead-spring models with different solvent representations, and to
random-interface models. Selected examples of simulations at the molecular and
the mesoscopic level are presented, and it is shown how simulations of
molecular coarse-grained models can bridge between different levels.
  The second part addresses simulation methods for complex fluids under shear.
After a brief introduction into the phenomenology (in particular for liquid
crystals), different non-equilibrium molecular dynamics (NEMD) methods are
introduced and compared to one another. Application examples include the
behavior of liquid crystal interfaces and lamellar surfactant phases under
shear. Finally, mesoscopic simulation approaches for liquid crystals under
shear are briefly discussed.


title: Localized Spins on Graphene

abstract:
  The problem of a magnetic impurity, atomic or molecular, absorbed on top of a
carbon atom in otherwise clean graphene is studied using the numerical
renormalization group. The spectral, thermodynamic, and scattering properties
of the impurity are described in detail. In the presence of a small magnetic
field, the low energy electronic features of graphene make possible to inject
spin polarized currents through the impurity using a scanning tunneling
microscope (STM). Furthermore, the impurity scattering becomes strongly spin
dependent and for a finite impurity concentration it leads to spin polarized
bulk currents and a large magnetoresistance. In gated graphene the impurity
spin is Kondo screened at low temperatures. However, at temperatures larger
than the Kondo temperature, the anomalous magnetotransport properties are
recovered.


title: A Natural Connection on (2,3) Sub-Riemannian Manifolds

abstract:
  We build an analogue for the Levi-Civita connection on Riemannian manifolds
for sub-Riemannian manfiolds modeled on the Heisenberg group. We demonstrate
some geometric properties of this connection to justify our choice and show
that this connection is unique in having these properties.


title: Low-Velocity Halo Clouds

abstract:
  Models that reproduce the observed high-velocity clouds (HVCs) also predict
clouds at lower radial velocities that may easily be confused with Galactic
disk (|z| < 1 kpc) gas. We describe the first search for these low-velocity
halo clouds (LVHCs) using IRAS data and the initial data from the Galactic
Arecibo L-band Feed Array survey in HI (GALFA-HI). The technique is based upon
the expectation that such clouds should, like HVCs, have very limited infrared
thermal dust emission as compared to their HI column density. We describe our
'displacement-map' technique for robustly determining the dust-to-gas ratio of
clouds and the associated errors that takes into account the significant
scatter in the infrared flux from the Galactic disk gas. We find that there
exist lower-velocity clouds that have extremely low dust-to-gas ratios,
consistent with being in the Galactic halo - candidate LVHCs. We also confirm
the lack of dust in many HVCs with the notable exception of complex M, which we
consider to be the first detection of warm dust in HVCs. We do not confirm the
previously reported detection of dust in complex C. In addition, we find that
most Intermediate- and Low-Velocity clouds that are part of the Galactic disk
have a higher 60 micron/100 micron flux ratio than is typically seen in
Galactic HI, which is consistent with a previously proposed picture in which
fast-moving Galactic clouds have smaller, hotter dust grains.


title:
The influence of star clusters on galactic disks: new insights on
  star-formation in galaxies

abstract:
  Stars form in embedded star clusters which play a key role in determining the
properties of a galaxy's stellar population. Physical mechanisms discussed in
this paper are runaway stars shot out from young clusters, binary-star
disruption in clusters, gas blow-out from clusters and the origin of thick
galactic disks. I emphasise that the SNIa rate per low-mass star depends on the
star-clusters formed in a galaxy and I discuss the IGIMF theory. Based on the
IGIMF theory, the re-calibrated Halpha-luminosity--SFR relation implies dwarf
irregular galaxies to have the same gas-depletion time-scale as major disk
galaxies, suggesting a major change in our understanding of dwarf-galaxy
evolution. The IGIMF-theory also naturally leads to the observed radial Halpha
cutoff in disk galaxies without a radial star-formation cutoff. It emerges that
the thorough understanding of the physics and distribution of star clusters may
be leading to a major paradigm shift in our understanding of galaxy evolution.


title: Quasar Clustering from SDSS DR5: Dependences on Physical Properties

abstract:
  Using a homogenous sample of 38,208 quasars with a sky coverage of $4000 {\rm
deg^2}$ drawn from the SDSS Data Release Five quasar catalog, we study the
dependence of quasar clustering on luminosity, virial black hole mass, quasar
color, and radio loudness. At $z<2.5$, quasar clustering depends weakly on
luminosity and virial black hole mass, with typical uncertainty levels $\sim
10%$ for the measured correlation lengths. These weak dependences are
consistent with models in which substantial scatter between quasar luminosity,
virial black hole mass and the host dark matter halo mass has diluted any
clustering difference, where halo mass is assumed to be the relevant quantity
that best correlates with clustering strength. However, the most luminous and
most massive quasars are more strongly clustered (at the $\sim 2\sigma$ level)
than the remainder of the sample, which we attribute to the rapid increase of
the bias factor at the high-mass end of host halos. We do not observe a strong
dependence of clustering strength on quasar colors within our sample. On the
other hand, radio-loud quasars are more strongly clustered than are radio-quiet
quasars matched in redshift and optical luminosity (or virial black hole mass),
consistent with local observations of radio galaxies and radio-loud type 2 AGN.
Thus radio-loud quasars reside in more massive and denser environments in the
biased halo clustering picture. Using the Sheth et al.(2001) formula for the
linear halo bias, the estimated host halo mass for radio-loud quasars is $\sim
10^{13} h^{-1}M_\odot$, compared to $\sim 2\times 10^{12} h^{-1}M_\odot$ for
radio-quiet quasar hosts at $z\sim 1.5$.


title:
Lensed CMB temperature and polarization maps from the Millennium
  Simulation

abstract:
  We have constructed the first all-sky CMB temperature and polarization lensed
maps based on a high-resolution cosmological N-body simulation, the Millennium
Simulation (MS). We have exploited the lensing potential map obtained using a
map-making procedure (Carbone et al. 2008) which integrates along the
line-of-sight the MS dark matter distribution by stacking and randomizing the
simulation boxes up to $z = 127$, and which semi-analytically supplies the
large-scale power in the angular lensing potential that is not correctly
sampled by the N-body simulation. The lensed sky has been obtained by properly
modifying the latest version of the LensPix code (Lewis 2005) to account for
the MS structures. We have also produced all-sky lensed maps of the so-called
$\psi_E$ and $\psi_B$ potentials, which are directly related to the electric
and magnetic types of polarization. The angular power spectra of the simulated
lensed temperature and polarization maps agree well with semi-analytic
estimates up to $l < 2500$, while on smaller scales we find a slight excess of
power which we interpret as being due to non-linear clustering in the MS. We
also observe how non-linear lensing power in the polarised CMB is transferred
to large angular scales by suitably misaligned modes in the CMB and the lensing
potential. This work is relevant in view of the future CMB probes, as a way to
analyse the lensed sky and disentangle the contribution from primordial
gravitational waves.


title: Fluctuating Interfaces in Liquid Crystals

abstract:
  We review and compare recent work on the properties of fluctuating interfaces
between nematic and isotropic liquid-crystalline phases. Molecular dynamics and
Monte Carlo simulations have been carried out for systems of ellipsoids and
hard rods with aspect ratio 15:1, and the fluctuation spectrum of interface
positions (the capillary wave spectrum) has been analyzed. In addition, the
capillary wave spectrum has been calculated analytically within the Landau-de
Gennes theory. The theory predicts that the interfacial fluctuations can be
described in terms of a wave vector dependent interfacial tension, which is
anisotropic at small wavelengths (stiff director regime) and becomes isotropic
at large wavelengths (flexible director regime). After determining the elastic
constants in the nematic phase, theory and simulation can be compared
quantitatively. We obtain good agreement for the stiff director regime. The
crossover to the flexible director regime is expected at wavelengths of the
order of several thousand particle diameters, which was not accessible to our
simulations.


title: Two component dark matter

abstract:
  We explain the PAMELA positron excess and the PPB-BETS/ATIC e+ + e- data
using a simple two component dark matter model (2DM). The two particle species
in the dark matter sector are assumed to be in thermal equilibrium in the early
universe. While one particle is stable and is the present day dark matter, the
second one is metastable and decays after the universe is 10^-8 s old. In this
model it is simple to accommodate the large boost factors required to explain
the PAMELA positron excess without the need for large spikes in the local dark
matter density. We provide the constraints on the parameters of the model and
comment on possible signals at future colliders.


title:
Modeling Molecular Hydrogen and Star Formation in Cosmological
  Simulations

abstract:
  We describe a phenomenological model for molecular hydrogen formation suited
for applications in galaxy formation simulations, which includes on-equilibrium
formation of molecular hydrogen on dust and approximate treatment of both its
self-shielding and shielding by dust from the dissociating UV radiation. The
model is applicable in simulations in which individual star forming regions -
the giant molecular complexes - can be identified (resolution of tens of pc)
and their mean internal density estimated reliably, even if internal structure
is not resolved. In agreement with previous studies, calculations based on our
model show that the transition from atomic to fully molecular phase depends
primarily on the metallicity, which we assume is directly related to the dust
abundance, and clumpiness of the interstellar medium. The clumpiness simply
boosts the formation rate of molecular hydrogen, while dust serves both as a
catalyst of molecular hydrogen formation and as an additional shielding from
dissociating UV radiation. The upshot is that it is difficult to form
fully-shielded giant molecular clouds while gas metallicity is low. However,
once the gas is enriched to Z ~ 0.01-0.1 solar, the subsequent star formation
and enrichment can proceed at a much faster rate. This may keep star formation
efficiency in the low-mass, low-metallicity progenitors of galaxies very low
for a certain period of time with the effect similar to a strong "feedback"
mechanism. [abridged]


title:
Pairing instability driven by macroscopically degenerate collective
  modes in two-dimensional rotating fermion liquids near unitarity

abstract:
  Fermionic superfluids can undergo phase transitions into different kinds of
normal regimes, loosely characterized by whether Cooper pairs remain locally
stable. If the normal phase retains strong pairing fluctuations, it behaves
like a liquid of vortices, which has been observed in cuprate superconductors.
We argue that analogous strongly correlated normal states exist in
two-dimensional neutral fermion liquids near unitarity, where superfluid is
destroyed by fast rotation. These states have non-universal properties, and if
they develop as distinct thermodynamic phases they can be characterized as
quantum Hall states of Cooper pairs. The formal analysis is based on a model
with SP(2N) symmetry that describes the quantum critical region in the vicinity
of a broad Feshbach resonance. We explore the pairing phase diagram and
demonstrate that the considered model has macroscopically degenerate bosonic
modes in the normal phase, to all orders in 1/N. It takes finite-range
interactions to lift this degeneracy, making the Abrikosov flux lattice of the
superfluid particularly susceptible to quantum melting.


title: Determining Star Formation Rates for Infrared Galaxies

abstract:
  We show that measures of star formation rates (SFRs) for infrared galaxies
using either single-band 24 um or extinction-corrected Paschen-alpha
luminosities are consistent in the total infrared luminosity = L(TIR) ~ 10^10
L_sun range. MIPS 24 micron photometry can yield star formation rates
accurately from this luminosity upward: SFR(M_sun/yr) = 7.8 x 10^-10 L(24 um,
L_sun) from L(TIR) = 5 x 10^9 L_sun to 10^11 L_sun, and SFR = 7.8 x 10^-10 L(24
um, L_sun) x (7.76 x 10^-11 L(24))^0.048 for higher L(TIR). For galaxies with
L(TIR) >= 10^10 L_sun, these new expressions should provide SFRs to within 0.2
dex. For L(TIR) >= 10^11 L_sun, we find that the SFR of infrared galaxies is
significantly underestimated using extinction-corrected Pa-alpha (and
presumably using any other optical or near infrared recombination lines). As a
part of this work, we constructed spectral energy distribution (SED) templates
for eleven luminous and ultraluminous purely star forming infrared galaxies
(LIRGs and ULIRGs) and over the spectral range 0.4 microns to 30 cm. We use
these templates and the SINGS data to construct average templates from 5
microns to 30 cm for infrared galaxies with L(TIR) = 5 x 10^9 to 10^13 L_sun.
All of these templates are made available on line.


title: Bistable anchoring of nematics on rough substrates

abstract:
  We analyze the interplay between wetting and anchoring of nematic liquid
crystals on disordering, e.g., rough substrates in the framework of the
Landau-de Gennes theory, in situations of competing homeotropic and planar easy
axes on the substrate and the nematic-isotropic (NI) interface. The phase
diagram for azimuthally symmetric substrates is calculated. We identify two
regimes - a strongly coupled regime, where the wetting transition coincides
with an anchoring transition, and a weakly coupled regime, where the two are
separated. The anchoring transition is first order and switches between
homeotropic and planar anchoring. The two competing orientations are metastable
over a broad parameter range. Hence such surfaces can be used to generate
bistable surfaces.


title: Quantum Machian Time in Toy Models of Gravity

abstract:
  General Relativity on closed spatial topologies can be derived, using a
technique called "best-matching", as an evolving 3-geometry subject to
constraints. These constraints can be thought of as a way of imposing temporal
and spatial relationalism. The same type of constraints can be used in
non-relativistic particle models to produce relational theories that suffer
from the same Problem of Time as that encountered in General Relativity. As a
result, these simple toy models are well suited for studying the Problem of
Time in quantum gravity. In this paper, a version of these particle models is
studied where we "best-match" the time translational invariance of the theory.
Using insights gained from this procedure, we can move back and forth between
absolute and relational time by changing the way in which the relational fields
are varied. We then proceed to quantize this theory using Dirac and path
integral quantizations. We discover that one of the constraints of the theory,
which we call the Mach constraint, is responsible for removing the dependence
of the theory on a background structure. It is this Mach constraint that is
responsible for making the theory temporally relational. Because of the deep
relationship between these models and General Relativity, this work may shed
new light on the Problem of Time in quantum gravity and how one might expect
time to emerge on quantum subsystems of the universe.


title:
From Knothe's transport to Brenier's map and a continuation method for
  optimal transport

abstract:
  A simple procedure to map two probability measures in $\mathbb{R}^d$ is the
so-called \emph{Knothe-Rosenblatt rearrangement}, which consists in rearranging
monotonically the marginal distributions of the last coordinate, and then the
conditional distributions, iteratively. We show that this mapping is the limit
of solutions to a class of Monge-Kantorovich mass transportation problems with
quadratic costs, with the weights of the coordinates asymptotically dominating
one another. This enables us to design a continuation method for numerically
solving the optimal transport problem.


title:
Formation of protostellar jets as two-component outflows from star-disk
  magnetospheres

abstract:
  Axisymmetric magnetohydrodynamic (MHD) simulations have been applied to
investigate the interrelation of a central stellar magnetosphere and stellar
wind with a surrounding magnetized disk outflow and how the overall formation
of a large scale jet is affected. The initial magnetic field distribution
applied is a superposition of two components - a stellar dipole and a
surrounding disk magnetic field, in both either parallel or anti-parallel
alignment. Correspondingly, the mass outflow is launched as stellar wind plus a
disk wind. Our simulations evolve from an initial state in hydrostatic
equilibrium and an initially force-free magnetic field configuration. Due to
initial differential rotation and induction of a strong toroidal magnetic field
the stellar dipolar field inflates and is disrupted on large scale. Stellar and
disk wind may evolve in a pair of collimated outflows. The existence of a
reasonably strong disk wind component is essential for collimation. A disk jet
as known from previous numerical studies will become de-collimated by the
stellar wind. In some simulations we observe the generation of strong flares
triggering a sudden change in the outflow mass loss rate by a factor of two and
also a re-distribution in the radial profile of momentum flux and jet velocity
across the jet. We discuss the hypothesis that these flares may trigger
internal shocks in the asymptotic jets which are observed as knots.


title: Modeling a high velocity LMC. The formation of the Magellanic Stream

abstract:
  I use high resolution N-body/SPH simulations to model the new proper motion
of the Large Magellanic Cloud (LMC) within the Milky Way (MW) halo and
investigate the effects of gravitational and hydrodynamical forces on the
formation of the Magellanic Stream (MS). Both the LMC and the MW are fully self
consistent galaxy models embedded in extended cuspy LCDM dark matter halos. I
find that ram-pressure from a low density ionized halo is sufficient to remove
a large amount of gas from the LMC's disk forming a trailing Stream that
extends more than 120 degrees from the Cloud. Tidal forces elongate the
satellite's disk but do not affect its vertical structure. No stars become
unbound showing that tidal stripping is almost effectiveless.


title:
Electronic transitions in disc-shaped quantum dots induced by twisted
  light

abstract:
  We theoretically investigate the absorption and emission of light carrying
orbital angular momentum (twisted-light) by quasi-two-dimensional (disc-shaped)
quantum dots in the presence of a static magnetic field. We calculate the
transition matrix element for the light-matter interaction and use it to
explore different scenarios, depending on the initial and final state of the
electron undergoing the optically-induced transition. We make explicit the
selection rule for the conservation of the z-projection of the orbital angular
momentum. For a realistic set of parameters (quantum dots size, beam waist,
photon energy, etc.) the strength of the transition induced by twisted light is
10% of that induced by plane-waves. Finally, our analysis indicates that it may
be possible to select precisely the electronic level one wishes to populate
using the appropriate combination of light-beam parameters suggesting
technological applications to the quantum control of electronic states in
quantum dots.


title: Quantum Curves and D-Modules

abstract:
  In this article we continue our study of chiral fermions on a quantum curve.
This system is embedded in string theory as an I-brane configuration, which
consists of D4 and D6-branes intersecting along a holomorphic curve in a
complex surface, together with a B-field. Mathematically, it is described by a
holonomic D-module. Here we focus on spectral curves, which play a prominent
role in the theory of (quantum) integrable hierarchies. We show how to
associate a quantum state to the I-brane system, and subsequently how to
compute quantum invariants. As a first example, this yields an insightful
formulation of (double scaled as well as general Hermitian) matrix models.
Secondly, we formulate c=1 string theory in this language. Finally, our
formalism elegantly reconstructs the complete dual Nekrasov-Okounkov partition
function from a quantum Seiberg-Witten curve.


title:
On the Debarre-de Jong and Beheshti-Starr conjectures on hypersurfaces
  with too many lines

abstract:
  We show that the Debarre-de Jong conjecture that the Fano scheme of lines on
a smooth hypersurface of degree at most n in n-dimensional projective space
must have its expected dimension, and the Beheshti-Starr conjecture that bounds
the dimension of the Fano scheme of lines for hypersurfaces of degree at least
n in n-dimensional projective space, reduce to determining if the intersection
of the top Chern classes of certain vector bundles is nonzero.


title:
Kohn anomaly and interplay of electron-electron and electron-phonon
  interactions in epitaxial graphene

abstract:
  The interplay of electron-phonon (el-ph) and electron-electron (el-el)
interactions in epitaxial graphene is studied by directly probing its
electronic structure. We found a strong coupling of electrons to the soft part
of the A1g phonon evident by a kink at 150+/-15 meV, while the coupling of
electrons to another expected phonon E2g at 195 meV can only be barely
detected. The possible role of the el-el interaction to account for the
enhanced coupling of electrons to the A1g phonon, and the contribution of el-ph
interaction to the linear imaginary part of the self energy at high binding
energy are also discussed. Our results reveal the dominant role of the A1g
phonon in the el-ph interaction in graphene, and highlight the important
interplay of el-el and el-ph interactions in the self energy of graphene.


title: Non-compact Mirror Bundles and (0,2) Liouville Theories

abstract:
  We study (0,2) deformations of N=2 Liouville field theory and its mirror
duality. A gauged linear sigma model construction of the ultraviolet theory
connects (0,2) deformations of Liouville field theory and (0,2) deformations of
N=2 SL(2,R)/U(1) coset model as a mirror duality. Our duality proposal from the
gauged linear sigma model completely agrees with the exact CFT analysis. In the
context of heterotic string compactifications, the deformation corresponds to
the introduction of a non-trivial gauge bundle. This non-compact
Landau-Ginzburg construction yields a novel way to study the gauge bundle
moduli for non-compact Calabi-Yau manifolds.


title: Enhanced stochastic oscillations in autocatalytic reactions

abstract:
  We study a simplified scheme of $k$ coupled autocatalytic reactions,
previously introduced by Togashi and Kaneko. The role of stochastic
fluctuations is elucidated through the use of the van Kampen system-size
expansion and the results compared with direct stochastic simulations. Regular
temporal oscillations are predicted to occur for the concentration of the
various chemical constituents, with an enhanced amplitude resulting from a
resonance which is induced by the intrinsic graininess of the system. The
associated power spectra are determined and have a different form depending on
the number of chemical constituents, $k$. We make detailed comparisons in the
two cases $k=4$ and $k=8$. Agreement between the theoretical and numerical
results for the power spectrum are good in both cases. The resulting spectrum
is especially interesting in the $k=8$ system, since it has two peaks, which
the system-size expansion is still able to reproduce accurately.


title:
Captured at Millimeter Wavelengths: a Flare from the Classical T Tauri
  Star DQ Tau

abstract:
  For several hours on 2008 April 19 the T Tauri spectroscopic binary DQ Tau
was observed to brighten, reaching a maximum detected flux of 468 mJy and
likely making it (briefly) the brightest object at 3 mm in the Taurus
star-forming region. We present the light curve of a rarely before observed
millimeter flare originating in the region around a pre-main-sequence star, and
the first from a classical T Tauri star. We discuss the properties and nature
of the flaring behavior in the context of pulsed accretion flows (the current
picture based largely on studies of this object's optically variable spectrum),
as well as magnetospheric re-connection models (a separate theory that predicts
millimeter flares for close binaries of high orbital eccentricity). We believe
that the flare mechanism is linked to the binary orbit, and therefore periodic.
DQ Tau makes a strong case for multi-wavelength follow-up studies, performed in
parallel, of future flares to help determine whether magnetospheric and
dynamical interactions in a proto-binary system are independent.


title:
Dispersion relation and spectral function of an impurity in a
  one-dimensional quantum liquid

abstract:
  We consider the motion of an impurity particle in a general one-dimensional
quantum fluid at zero temperature. The dispersion relation $\Omega(P)$ of the
impurity is strongly affected by interactions with the fluid as the momentum
approaches $\pm\pi\hbar n, \pm 3\pi\hbar n, ...$, where $n$ is the density.
This behavior is caused by singular $\pm 2\pi\hbar n$ scattering processes and
can be understood by analogy to the Kondo effect, both at strong and weak
coupling, with the possibility of a quantum phase transition where $\Omega'(\pm
\pi n)$ jumps to zero with increasing coupling. The low energy singularities in
the impurity spectral function can be understood on the same footing.


title: Models and van Kampen theorems for directed homotopy theory

abstract:
  We study topological spaces with a distinguished set of paths, called
directed paths. Since these directed paths are generally not reversible, the
directed homotopy classes of directed paths do not assemble into a groupoid,
and there is no direct analog of the fundamental group. However, they do
assemble into a category, called the fundamental category. We define models of
the fundamental category, such as the fundamental bipartite graph, and minimal
extremal models which are shown to generalize the fundamental group. In
addition, we prove van Kampen theorems for subcategories, retracts, and models
of the fundamental category.


title: A Contribution for the Construction of Parabolic Mirrors

abstract:
  We present a new procedure for the construction of parabolic mirrors using
low cost materials. We build a spinning system composed of nylon threads, fish
hooks and a plastic bucket. We pour liquid plaster into the bucket and set it
in constant rotational motion relative to the earth. A liquid substance assumes
a parabolic profile when spinning at constant angular velocity relative to an
inertial frame under the influence of an uniform vertical gravitational field.
By keeping the bucket under rotation for a long time, the plaster solidifies
into a parabolic format. We utilize this solidified plaster paraboloid as a
model to construct a counter-mould of glass fibre and resin. Over this
counter-mould it is placed stretched laminated foil and then it is poured thick
plaster over it. In this way it is obtained a parabolic mirror made of
laminated foil and plaster. Our only objective here is to present a new method
for the construction of parabolic mirror using low cost materials. This allows
further exploration of this procedure by teachers and students either in
high-schools or in universities.


title:
Compactons and kink-like solutions of BBM-like equations by means of
  factorization

abstract:
  In this work, we study the Benjamin-Bona-Mahony like equations with a fully
nonlinear dispersive term by means of the factorization technique. In this way
we find the travelling wave solutions of this equation in terms of the
Weierstrass function and its degenerated trigonometric and hyperbolic forms.
Then, we obtain the pattern of periodic, solitary, compacton and kink-like
solutions. We give also the Lagrangian and the Hamiltonian, which are linked to
the factorization, for the nonlinear second order ordinary differential
equations associated to the travelling wave equations.


title: The population of Magellanic Cloud planetary nebulae

abstract:
  In this review we address the progress that has been made toward the
understanding the population of Magellanic Cloud planetary nebulae since the
last Magellanic Cloud Symposium. Planetary nebulae in the Clouds are not only
important as key probes of stellar and ISM evolution in these galaxies, but
also reflect the evolution of AGB stars and beyond in low-metallicity
environments. We present the recent surveys results, including the wide fields
ground-based search for PNe, the {\it HST} study of the resolves ejecta and
their central stars, and the {\it Spitzer} analysis of the gas contents of
these ejecta. Finally, we show how Magellanic Cloud PNe can be used to
constraint the distance scale of galactic PNe.


title: The transmission sense of information

abstract:
  Biologists rely heavily on the language of information, coding, and
transmission that is commonplace in the field of information theory as
developed by Claude Shannon, but there is open debate about whether such
language is anything more than facile metaphor. Philosophers of biology have
argued that when biologists talk about information in genes and in evolution,
they are not talking about the sort of information that Shannon's theory
addresses. First, philosophers have suggested that Shannon theory is only
useful for developing a shallow notion of correlation, the so-called "causal
sense" of information. Second they typically argue that in genetics and
evolutionary biology, information language is used in a "semantic sense,"
whereas semantics are deliberately omitted from Shannon theory. Neither
critique is well-founded. Here we propose an alternative to the causal and
semantic senses of information: a transmission sense of information, in which
an object X conveys information if the function of X is to reduce, by virtue of
its sequence properties, uncertainty on the part of an agent who observes X.
The transmission sense not only captures much of what biologists intend when
they talk about information in genes, but also brings Shannon's theory back to
the fore. By taking the viewpoint of a communications engineer and focusing on
the decision problem of how information is to be packaged for transport, this
approach resolves several problems that have plagued the information concept in
biology, and highlights a number of important features of the way that
information is encoded, stored, and transmitted as genetic sequence.


title:
Interference of guiding polariton mode in "traffic" circle waveguides
  composed of dielectric spherical particles

abstract:
  The interference of polariton guiding modes propagating through "traffic
circle" waveguides composed of dielectric spherical particles is investigated.
The dependence of intensity of the wave on the position of the particle was
studied using the multisphere the Mie scattering formalism. We show that if the
frequency of light belongs to the passband of the waveguide, electromagnetic
waves may be considered as two optical beams running along a circle in opposite
directions and interfering with each other. Indeed, the obtained intensity
behavior can be represented as a simple superposition of two waves propagating
around a circle in opposite directions. The applications of this interference
are discussed.


title: The Impact of Non-Gaussian Errors on Weak Lensing Surveys

abstract:
  The weak lensing power spectrum carries cosmological information via its
dependence on the growth of structure and on geometric factors. Since much of
the cosmological information comes from scales affected by nonlinear
clustering, measurements of the lensing power spectrum can be degraded by
non-Gaussian covariances. Recently there have been conflicting studies about
the level of this degradation. We use the halo model to estimate it and include
new contributions related to the finite size of lensing surveys, following
Rimes and Hamilton's study of 3D simulations. We find that non-Gaussian
correlations between different multipoles can degrade the cumulative
signal-to-noise for the power spectrum amplitude by up to a factor of 2 (or 5
for a worst-case model that exceeds current N-body simulation predictions).
However, using an eight-parameter Fisher analysis we find that the marginalized
errors on individual parameters are degraded by less than 10% (or 20% for the
worst-case model). The smaller degradation in parameter accuracy is primarily
because: individual parameters in a high-dimensional parameter space are
degraded much less than the volume of the full Fisher ellipsoid; lensing
involves projections along the line of sight, which reduce the non-Gaussian
effect; some of the cosmological information comes from geometric factors which
are not degraded at all. We contrast our findings with those of Lee & Pen
(2008) who suggested a much larger degradation in information content. Finally,
our results give a useful guide for exploring survey design by giving the
cosmological information returns for varying survey area, depth and the level
of some systematic errors.


title: Capacity of Steganographic Channels

abstract:
  This work investigates a central problem in steganography, that is: How much
data can safely be hidden without being detected? To answer this question, a
formal definition of steganographic capacity is presented. Once this has been
defined, a general formula for the capacity is developed. The formula is
applicable to a very broad spectrum of channels due to the use of an
information-spectrum approach. This approach allows for the analysis of
arbitrary steganalyzers as well as non-stationary, non-ergodic encoder and
attack channels.
  After the general formula is presented, various simplifications are applied
to gain insight into example hiding and detection methodologies. Finally, the
context and applications of the work are summarized in a general discussion.


title: Thermal (in)stability of type I collagen fibrils

abstract:
  We measured Young's modulus at temperatures ranging from 20 to 100 ^{\circ}$C
for a collagen fibril taken from rat's tendon. The hydration change under
heating and the damping decrement were measured as well. At physiological
temperatures $25-45^{\circ}$C Young's modulus decreases, which can be
interpreted as instability of collagen. For temperatures between
$45-80^{\circ}$C Young's modulus first stabilizes and then increases with
decreasing the temperature. The hydrated water content and the damping
decrement have strong maxima in the interval $70-80^{\circ}$C indicating on
complex inter-molecular structural changes in the fibril. All these effects
disappear after heat-denaturating the sample at $120^\circ$C. Our main result
is a five-stage mechanism by which the instability of a single collagen at
physiological temperatures is compensated by the interaction between collagen
molecules within the fibril.


title: Etude de deux classes de groupes nilpotents de pas deux

abstract:
  The aim of my PhD work is to study the $L^p$-boundedness of operators on two
classes of two-step nilpotent Lie groups, using Plancherel formulas and
spherical functions as tools. The first class of groups consists of the groups
of Heisenberg type, and the second, of the two-step free nilpotent Lie groups
(denoted $N_{v,2}$ for $v$ generators). In the latter case, we develop a radial
Fourier calculus. Our study has focused on the maximal functions associated
with Kor\'anyi spheres, together with their square functions, and the
convolution operator defined with the radial Fourier calculus on the two-step
free nilpotent Lie group (radial Fourier multipliers problem). In fact, one
chapter of this work is devoted to the proof of $L^p$-inequalities for the
maximal spherical function on the two considered classes of groups. Our method
is based on interpolation for the same operator family as in the euclidean
case, on $L^p$-boundedness for the standard maximal function, and
$L^2$-inequalities for square functions. These $L^2$-inequalities are based on
Plancherel formula and on the properties of bounded spherical functions for the
orthogonal group. On $N_{v,2}$, we construct the bounded spherical functions
using representations of the semidirect product of $N_{v,2}$ with the
orthogonal group. We also obtain some properties of the Kohn sublaplacian and
the radial Plancherel measure. Then we present a first study of the radial
Fourier multiplier problem, with the aim of giving our solutions for some
technicals difficulties.


title: Correlators and Descendants of Subcritical Stein Manifolds

abstract:
  We determine contact homology algebra of a subcritical Stein-fillable contact
manifold whose first Chern class vanishes. We also compute the genus-0 one
point correlators and gravitational descendants of compactly supported closed
forms of their subcritical Stein fillings. This is a step towards determining
the full potential function of the filling as defined in
\cite{EliashbergGiventalHofer}. These invariants also give a canonical
presentation of the cylindrical contact homology. With respect to this
presentation, we determine the degree-2 differential in the Bourgeois--Oancea
exact sequence of \cite{Oancea}. As a further application, we proved that if a
K\"{a}hler manifold $M^{2n}$ admits a subcritical polarization and $c_1$
vanishes in the subcritical complement, then $M$ is uniruled.


title: Top quark physics expectations at the LHC

abstract:
  The top quark will be produced copiously at the LHC. This will make both
detailed physics studies and the use of top quark decays for detector
calibration possible. This talk reviews plans and prospects for top physics
activities in the ATLAS and CMS experiments.


title: Top quark theory review for the Tevatron, LHC, and ILC

abstract:
  I will briefly review the status of higher-order calculations for top-quark
observables, comment on the need for improvements, discuss some of the recent
theoretical advances, and present a few examples to highlight the role of
top-quark observables in searches for signals of physics beyond the Standard
Model.


title: The Spherical Maximal Function on the Free Two-step Nilpotent Lie Group

abstract:
  We consider here the free two step nilpotent Lie group, provided with the
homogeneous Kor\'anyi norm; we prove the $L^p$-boundedness of the maximal
function corresponding to the homogeneous unit sphere, for some $p$.


title: Color singlet and adjoint free energy at finite temperature

abstract:
  We study correlation functions of static quark-antiquark pairs in SU(2) gauge
theory at finite temperature. By measuring Polyakov loop correlators and
temporal Wilson loops with APE smearing of spatial links we are able to give
consistent definitions of the singlet and adjoint free energies at short
distances, where the notion of these free energies is meaningful. APE smearing
procedure allows to achieve a high degree of overlap in the singlet channel and
to reconstruct the adjoint part from the color averaged and singlet free
energy.


title: Memristive model of amoeba's learning

abstract:
  Recently, it was shown that the amoeba-like cell {\it Physarum polycephalum}
when exposed to a pattern of periodic environmental changes learns and adapts
its behavior in anticipation of the next stimulus to come. Here we show that
such behavior can be mapped into the response of a simple electronic circuit
consisting of an $LC$ contour and a memory-resistor (a memristor) to a train of
voltage pulses that mimic environment changes. We also identify a possible
biological origin of the memristive behavior in the cell. These biological
memory features are likely to occur in other unicellular as well as
multicellular organisms, albeit in different forms. Therefore, the above
memristive circuit model, which has learning properties, is useful to better
understand the origins of primitive intelligence.


title:
Discovery of a redshift 6.13 quasar in the UKIRT Infrared Deep Sky
  Survey

abstract:
  Optical and near-infrared (NIR) spectra are presented for ULAS
J131911.29+095951.4 (hereafter ULAS J1319+0950), a new redshift z = 6.127 +/-
0.004 quasar discovered in the Third Data Release (DR3) of the UKIRT Infrared
Deep Sky Survey (UKIDSS). The source has Y_Vega = 19.10 +/- 0.03, corresponding
to M_1450,AB = -27.12, which is comparable to the absolute magnitudes of the z
~= 6 quasars discovered in the SDSS. ULAS J1319+0950 was, in fact, registered
by SDSS as a faint source with z_AB = 20.1 +/- 0.1, just below the
signal--to--noise ratio limit of the SDSS high-redshift quasar survey. The
faint z-band magnitude is a consequence of the weak Ly alpha/N V emission line,
which has a rest-frame equivalent width of only ~20 A and provides only a small
boost to the z-band flux. Nevertheless, there is no evidence from this
UKIDSS-based search for a significant population of high-redshift quasars with
weak emission lines. The Ly alpha optical depth to ULAS J1319+0950 is
consistent with that measured towards similarly distant SDSS quasars, implying
that results from optical- and NIR-selected quasars may be combined.
  Also presented is a new NIR-spectrum of the previously discovered UKIDSS
quasar ULAS J020332.38+001229.2, which reveals the object to be a broad
absorption line quasar. The new spectrum shows that the emission line
previously identified as Ly alpha is actually N V, leading to a revised
redshift of z = 5.72, rather than z = 5.86 as previously estimated.


title: Shear viscosity of pure Yang-Mills theory at strong coupling

abstract:
  We calculate the shear viscosity to entropy density ratio in pure SU(N)
Yang-Mills theory below the critical temperature using the strong coupling
expansion. The result for the eta/s ratio for temperatures around the phase
transition is 0.22 for N = 2 and 0.028N^2 for N > 2. The results are consistent
with the conjectured 1/4pi lower bound inspired by the AdS/CFT correspondence.


title:
Bucketing Coding and Information Theory for the Statistical High
  Dimensional Nearest Neighbor Problem

abstract:
  Consider the problem of finding high dimensional approximate nearest
neighbors, where the data is generated by some known probabilistic model. We
will investigate a large natural class of algorithms which we call bucketing
codes. We will define bucketing information, prove that it bounds the
performance of all bucketing codes, and that the bucketing information bound
can be asymptotically attained by randomly constructed bucketing codes.
  For example suppose we have n Bernoulli(1/2) very long (length d-->infinity)
sequences of bits. Let n-2m sequences be completely independent, while the
remaining 2m sequences are composed of m independent pairs. The interdependence
within each pair is that their bits agree with probability 1/2<p<=1. It is well
known how to find most pairs with high probability by performing order of
n^{\log_{2}2/p} comparisons. We will see that order of n^{1/p+\epsilon}
comparisons suffice, for any \epsilon>0. Moreover if one sequence out of each
pair belongs to a a known set of n^{(2p-1)^{2}-\epsilon} sequences, than
pairing can be done using order n comparisons!


title: On converting a side-pairing to a handle decomposition

abstract:
  We give a method for obtaining a handle decomposition of an $n$-manifold if
the manifold is given by isometric side-pairings of a polyhedron in $\en$,
$\sn$ or $\hn$. Every cycle of $k$-faces on the polyhedron corresponds to an
$(n-k)$-handle of the manifold.
  Two applications of the method are given. One helps recognize when a
noncompact hyperbolic 3-manifold is a complement of a link in $S^3$ (and
automatically produces the link diagram), the other shows that a topological
$S^4$ described by the author in \cite{Ivansic3} is diffeomorphic to the
standard differentiable $S^4$.


title: Constraining the Proper Motions of Two Magnetars

abstract:
  We attempt to measure the proper motions of two magnetars - the soft
gamma-ray repeater SGR 1900+14 and the anomalous X-ray pulsar 1E 2259+586 -
using two epochs of Chandra observations separated by ~5 yr. We perform
extensive tests using these data, archival data, and simulations to verify the
accuracy of our measurements and understand their limitations. We find 90%
upper limits on the proper motions of 54 mas/yr (SGR 1900+14) and 65 mas/yr (1E
2259+586), with the limits largely determined by the accuracy with which we
could register the two epochs of data and by the inherent uncertainties on
two-point proper motions. We translate the proper motions limits into limits on
the transverse velocity using distances, and find v_perp < 1300 km/s (SGR
1900+14, for a distance of 5 kpc) and v_perp < 930 km/s (1E 2259+586, for a
distance of 3 kpc) at 90% confidence; the range of possible distances for these
objects makes a wide range of velocities possible, but it seems that the
magnetars do not have uniformly high space velocities of > 3000 km/s.
Unfortunately, our proper motions also cannot significantly constrain the
previously proposed origins of these objects in nearby supernova remnants or
star clusters, limited as much by our ignorance of ages as by our proper
motions.


title:
On the discrepancy principle for some Newton type methods for solving
  nonlinear inverse problems

abstract:
  We consider the computation of stable approximations to the exact solution
$x^\dag$ of nonlinear ill-posed inverse problems $F(x)=y$ with nonlinear
operators $F:X\to Y$ between two Hilbert spaces $X$ and $Y$ by the Newton type
methods $$ x_{k+1}^\delta=x_0-g_{\alpha_k} (F'(x_k^\delta)^*F'(x_k^\delta))
F'(x_k^\delta)^* (F(x_k^\delta)-y^\delta-F'(x_k^\delta)(x_k^\delta-x_0)) $$ in
the case that only available data is a noise $y^\delta$ of $y$ satisfying
$\|y^\delta-y\|\le \delta$ with a given small noise level $\delta>0$. We
terminate the iteration by the discrepancy principle in which the stopping
index $k_\delta$ is determined as the first integer such that $$
\|F(x_{k_\delta}^\delta)-y^\delta\|\le \tau \delta <\|F(x_k^\delta)-y^\delta\|,
\qquad 0\le k<k_\delta $$ with a given number $\tau>1$. Under certain
conditions on $\{\alpha_k\}$, $\{g_\alpha\}$ and $F$, we prove that
$x_{k_\delta}^\delta$ converges to $x^\dag$ as $\delta\to 0$ and establish
various order optimal convergence rate results. It is remarkable that we even
can show the order optimality under merely the Lipschitz condition on the
Fr\'{e}chet derivative $F'$ of $F$ if $x_0-x^\dag$ is smooth enough.


title: Planar algebras: a category theoretic point of view

abstract:
  We define Jones's planar algebra as a map of multicategories and constuct a
planar algebra starting from a 1-cell in a pivotal strict 2-category. We prove
finiteness results for the affine representations of finite depth planar
algebras. We also show that the radius of convergence of the dimension of an
affine representation of the planar algebra associated to a finite depth
subfactor is at least as big as the inverse-square of the modulus.


title:
Bicycle cycles and mobility patterns - Exploring and characterizing data
  from a community bicycle program

abstract:
  This paper provides an analysis of human mobility data in an urban area using
the amount of available bikes in the stations of the community bicycle program
Bicing in Barcelona. The data was obtained by periodic mining of a KML-file
accessible through the Bicing website. Although in principle very noisy, after
some preprocessing and filtering steps the data allows to detect temporal
patterns in mobility as well as identify residential, university, business and
leisure areas of the city. The results lead to a proposal for an improvement of
the bicing website, including a prediction of the number of available bikes in
a certain station within the next minutes/hours. Furthermore a model for
identifying the most probable routes between stations is briefly sketched.


title: A Heterogeneous High Dimensional Approximate Nearest Neighbor Algorithm

abstract:
  We consider the problem of finding high dimensional approximate nearest
neighbors. Suppose there are d independent rare features, each having its own
independent statistics. A point x will have x_{i}=0 denote the absence of
feature i, and x_{i}=1 its existence. Sparsity means that usually x_{i}=0.
Distance between points is a variant of the Hamming distance. Dimensional
reduction converts the sparse heterogeneous problem into a lower dimensional
full homogeneous problem. However we will see that the converted problem can be
much harder to solve than the original problem. Instead we suggest a direct
approach. It consists of T tries. In try t we rearrange the coordinates in
decreasing order of (1-r_{t,i})\frac{p_{i,11}}{p_{i,01}+p_{i,10}}
\ln\frac{1}{p_{i,1*}} where 0<r_{t,i}<1 are uniform pseudo-random numbers, and
the p's are the coordinate's statistical parameters. The points are
lexicographically ordered, and each is compared to its neighbors in that order.
  We analyze a generalization of this algorithm, show that it is optimal in
some class of algorithms, and estimate the necessary number of tries to
success. It is governed by an information like function, which we call
bucketing forest information. Any doubts whether it is "information" are
dispelled by another paper, where unrestricted bucketing information is
defined.


title: New Experimental Limit on Photon Hidden-Sector Paraphoton Mixing

abstract:
  We report on the first results of a search for optical-wavelength photons
mixing with hypothetical hidden-sector paraphotons in the mass range between
10^-5 and 10^-2 electron volts for a mixing parameter greater than 10^-7. This
was a generation-regeneration experiment using the "light shining through a
wall" technique in which regenerated photons are searched for downstream of an
optical barrier that separates it from an upstream generation region. The new
limits presented here are approximately three times more sensitive to this
mixing than the best previous measurement. The present results indicate no
evidence for photon-paraphoton mixing for the range of parameters investigated.


title:
The existence results for solutions of indefinite scalar curvature
  problem

abstract:
  In this paper, we consider the indefinite scalar curvature problem on $R^n$.
We propose new conditions on the prescribing scalar curvature function such
that the scalar curvature problem on $R^n$ (similarly, on $S^n$) has at least
one solution. The key observation in our proof is that we use the bifurcation
method to get a large solution and then after establishing the Harnack
inequality for solutions near the critical points of the prescribed scalar
curvature and taking limit, we find the nontrivial positive solution to the
indefinite scalar curvature problem.


title: Survey on recent invariants on classical knot theory

abstract:
  The survey we are presenting is over 22 years old but it has still some ideas
which where never published (except in Polish). This survey is the base of the
third Chapter of my book: KNOTS: From combinatorics of knot diagrams to
combinatorial topology based on knots, which is still in preparation (but
compare http://arxiv.org/pdf/math.GT/0512630).
  The purpose of this survey is to present a new combinatorial method of
constructing invariants of isotopy classes of tame links. The period of time
between the spring of 1984 and the summer of 1985 was full of discoveries which
revolutionized the knot theory and will have a deep impact on some other
branches of mathematics. It started by the discovery of Jones of the new
polynomial invariant of links (in May 1984), and the last big step (which will
be described in this survey) has been made by Kauffman in August 1985 when
Kauffman applied his method which allowed him to unify almost all previous
work. This survey is far from being complete, even if we limit ourselves to the
purely combinatorial methods and to the period May, 1984 -- September, 1985.


title: Pseudospin and Deformation-induced Gauge Field in Graphene

abstract:
  The basic properties of $\pi$-electrons near the Fermi level in graphene are
reviewed from a point of view of the pseudospin and a gauge field coupling to
the pseudospin. The applications of the gauge field to the electron-phonon
interaction and to the edge states are reported.


title:
Exact Analysis of Scaling and Dominant Attractors Beyond the Exponential
  Potential

abstract:
  By considering the potential parameter $\Gamma$ as a function of another
potential parameter $\lambda$[47], We successfully extend the analysis of
two-dimensional autonomous dynamical system of quintessence scalar field model
to the analysis of three-dimension, which makes us be able to research the
critical points of a large number of potentials beyond the exponential
potential exactly. We find that there are ten critical points in all, three
points $P_{3, 5, 6}$} are general points which are possessed by all
quintessence models regardless of the form of potentials and the rest points
are closely connected to the concrete potentials. It is quite surprising that,
apart from the exponential potential, there are a large number of potentials
which can give the scaling solution when the function
$f(\lambda)(=\Gamma(\lambda)-1)$ equals zero for one or some values of
$\lambda_{*}$ and if the parameter $\lambda_{*}$ also satisfies the condition
Eq.(16) or Eq.(17) at the same time. We give the differential equations to
derive these potentials $V(\phi)$ from $f(\lambda)$. We also find that, if some
conditions are satisfied, the de-Sitter-like dominant point $P_4$ and the
scaling solution point $P_9$(or $P_{10}$) can be stable simultaneously but
$P_9$ and $P_{10}$ can not be stable simultaneity. Although we survey scaling
solutions beyond the exponential potential for ordinary quintessence models in
standard general relativity, this method can be applied to other extensively
scaling solution models studied in literature[46] including coupled
quintessence, (coupled-)phantom scalar field, k-essence and even beyond the
general relativity case $H^2 \propto\rho_T^n$. we also discuss the disadvantage
of our approach.


title:
Higgs bosons of a supersymmetric $E_6$ model at the Large Hadron
  Collider

abstract:
  It is found that CP symmetry may be explicitly broken in the Higgs sector of
a supersymmetric $E_6$ model with two extra neutral gauge bosons at the
one-loop level. The phenomenology of the model, the Higgs sector in particular,
is studied for a reasonable parameter space of the model, in the presence of
explicit CP violation at the one-loop level. At least one of the neutral Higgs
bosons of the model might be produced via the $WW$ fusion process at the Large
Hadron Collider.


title: Numerical properties of isotrivial fibrations

abstract:
  In this paper we investigate the numerical properties of relatively minimal
isotrivial fibrations $\varphi \colon X \lr C$, where $X$ is a smooth,
projective surface and $C$ is a curve. In particular we prove that, if $g(C)
\geq 1$ and $X$ is neither ruled nor isomorphic to a quasi-bundle, then $K_X^2
\leq 8 \chi(\mO_X)-2$; this inequality is sharp and if equality holds then $X$
is a minimal surface of general type whose canonical model has precisely two
ordinary double points as singularities. Under the further assumption that
$K_X$ is ample, we obtain $K_X^2 \leq 8 \chi(\mO_X)-5$ and the inequality is
also sharp. This improves previous results of Serrano and Tan.


title: Interval Semantics for Standard Floating-Point Arithmetic

abstract:
  If the non-zero finite floating-point numbers are interpreted as point
intervals, then the effect of rounding can be interpreted as computing one of
the bounds of the result according to interval arithmetic. We give an interval
interpretation for the signed zeros and infinities, so that the undefined
operations 0*inf, inf - inf, inf/inf, and 0/0 become defined.
  In this way no operation remains that gives rise to an error condition.
Mathematically questionable features of the floating-point standard become
well-defined sets of reals. Interval semantics provides a basis for the
verification of numerical algorithms. We derive the results of the newly
defined operations and consider the implications for hardware implementation.


title:
Weak localization and magnetoconductance of Dirac fermions under charged
  impurities in graphene

abstract:
  On the basis of self-consistent Born approximation, we present a theory of
weak localization of Dirac fermions under finite-range scatters in graphene.
With an explicit solution to the ground state of singlet pseudospin Cooperons,
we solve the Bethe-Salpeter matrix equation for all the singlet and triplet
pseudospin Cooperons at long-wave length states by perturbation treatment. The
solution to the Cooperon in the presence of the external weak magnetic field is
also obtained. We calculate the quantum interference correction to the
conductivity and present the comparison with experiments. It is shown that the
present calculation for the magnetoconductivity is in good agreement with some
of the experimental measurements.


title: Temperature-dependent Drude transport in a two-dimensional electron gas

abstract:
  We consider transport of dilute two-dimensional electrons, with temperature
between Fermi and Debye temperatures. In this regime, electrons form a
nondegenerate plasma with mobility limited by potential disorder. Different
kinds of impurities contribute unique signatures to the resulting
temperature-dependent Drude conductivity, via energy-dependent scattering. This
opens up a way to characterize sample disorder composition. In particular,
neutral impurities cause a slow decrease in conductivity with temperature,
whereas charged impurities result in conductivity growing as a square root of
temperature. This observation serves as a precaution for literally interpreting
metallic or insulating conductivity dependence, as both can be found in a
classical metallic system.


title:
Classical and quantum dynamics of pulsating instability in a
  Bose-Einstein condensate in an optical lattice

abstract:
  We study the dynamics of a Bose-Einstein condensate (BEC) in a one
dimensional optical lattice in the limit of weak atom-atom interactions.
Numerically we find that a BEC may develop a pulsating instability in which
atoms nearly periodically collect themselves into a pulse and subsequently
disperse back into the initial homogeneous state. A qualitative explanation of
the quasi-periodic behavior is given by drawing an analogy with a double-well
system. In an extension we introduce quantum effects approximately within
Truncated Wigner Approximation (TWA). In pure classical mean field theory the
condensate shows an undamped pulsating instability, whereas we have observed a
damping in the oscillation when we average over many stochastic realizations.


title: Dirac Spectra and Edge States in Honeycomb Plasmonic Lattices

abstract:
  We study theoretically the dispersion of plasmonic honeycomb lattices and
find Dirac spectra for both dipole and quadrupole modes. Zigzag edge states
derived from Dirac points are found in ribbons of these honeycomb plasmonic
lattices. The zigzag edge states for out-of-plane dipole modes are closely
analogous to the electronic ones in graphene nanoribbons. The edge states for
in-plane dipole modes and quadrupole modes, however, have rather unique
characters due to the vector nature of the plasmonic excitations. The
conditions for the existence of plasmonic edge states are derived analytically.


title: Interchanging Interactive 3-d Graphics for Astronomy

abstract:
  We demonstrate how interactive, three-dimensional (3-d) scientific
visualizations can be efficiently interchanged between a variety of mediums.
Through the use of an appropriate interchange format, and a unified interaction
interface, we minimize the effort to produce visualizations appropriate for
undertaking knowledge discovery at the astronomer's desktop, as part of
conference presentations, in digital publications or as Web content. We use
examples from cosmological visualization to address some of the issues of
interchange, and to describe our approach to adapting S2PLOT desktop
visualizations to the Web.
  Supporting demonstrations are available at
http://astronomy.swin.edu.au/s2plot/interchange/


title: Spin-1/2 kagome compounds: volborthite vs herbertsmithite

abstract:
  Two kagome compounds, volborthite Cu3V2O7(OH)2-2H2O and herbertsmithite
ZnCu3(OH)6Cl2, are compared in order to derive information about the intrinsic
properties of the spin-1/2 kagome antiferromagnet. Volborthite shows a broad
maximum at T ~ J / 4 and the approach at T = 0 to a large finite value of the
bulk magnetic susceptibility chi_bulk as well as the local susceptibility
chi_local from NMR measurements. These must be intrinsic properties for the
spin-1/2 kagome antiferromagnet, as similar behavior has also been reported in
chi_local for herbertsmithite [Olariu A et al. 2008 Phys. Rev. Lett., 100
087202]. Impurity effects that may significantly influence the bulk properties
are discussed.


title: Extended obstruction tensors and renormalized volume coefficients

abstract:
  The behavior under conformal change of the renormalized volume coefficients
associated to a pseudo-Riemannian metric is investigated. It is shown that they
define second order fully nonlinear operators in the conformal factor whose
algebraic structure is elucidated via the introduction of "extended obstruction
tensors". These together with the Schouten tensor constitute building blocks
for the coefficients in the ambient metric expansion. The renormalized volume
coefficients have recently been considered by Chang-Fang motivated by
comparison with the elementary symmetric functions of the eigenvalues of the
Schouten tensor.


title: Analytic torsion for twisted de Rham complexes

abstract:
  We define analytic torsion for the twisted de Rham complex, consisting of the
spaces of differential forms on a compact oriented Riemannian manifold X valued
in a flat vector bundle E, with a differential given by a flat connection on E
plus an odd-degree closed differential form H on X. The difficulty lies in the
fact that the twisted de Rham complex is only Z_2-graded, and so the definition
of analytic torsion in this case uses pseudo-differential operators and residue
traces. We show that when dim X is odd, then the twisted analytic torsion is
independent of the choice of metrics on X and E and of the representative H in
the cohomology class of H. We define twisted analytic torsion in the context of
generalized geometry and show that when H is a 3-form, the deformation H -> H -
dB, where B is a 2-form on X, is equivalent to deforming a usual metric g to a
generalized metric (g,B). We establish some basic functorial properties. When H
is a top-degree form, we compute the torsion, define its simplicial counterpart
and prove an analogue of the Cheeger-Muller Theorem. We also study the
relationship of the analytic torsion for T-dual circle bundles with integral
3-form fluxes.


title: Buried Points in Julia Sets

abstract:
  We give an introduction to buried points in Julia sets and a list of
questions about buried points, written to encourage aficionados of topology and
dynamics to work on these questions.


title: Quantum Optomechanics with Single Atom

abstract:
  The recently increasing explorations for cavity optomechanical coupling
assisted by a single atom or an atomic ensemble have opened an experimentally
accessible fashion to interface quantum optics and nano (micro) -mechanical
systems. In this paper, we study in details such composite quantum dynamics of
photon, phonon and atoms, specified by the triple coupling, which only exists
in this triple hybrid system: The cavity QED system with a movable end mirror.
We exactly diagonalize the Hamiltonian of the triple hybrid system under the
parametric resonance condition. We find that, with the rotating-wave
approximation, the hybrid system is modeled by a generalized spin-orbit
coupling where the orbital angular momentum operator is defined through a
Jordan-Schwinger realization with two bosonic modes, corresponding to the
mirror oscillation and the single mode photon of the cavity. In the
quasi-classical limit of very large angular momentum, this system will behave
like a standard cavity-QED system described by the Jaynes-Cummings model as the
angular momentum operators are transformed to bosonic operators of a single
mode. We test this observation with an experimentally accessible system with
the atom in the cavity with a moving mirror.


title:
Localized matter-waves patterns with attractive interaction in rotating
  potentials

abstract:
  We consider a two-dimensional (2D) model of a rotating attractive
Bose-Einstein condensate (BEC), trapped in an external potential. First, an
harmonic potential with the critical strength is considered, which generates
quasi-solitons at the lowest Landau level (LLL). We describe a family of the
LLL quasi-solitons using both numerical method and a variational approximation
(VA), which are in good agreement with each other. We demonstrate that kicking
the LLL mode or applying a ramp potential sets it in the Larmor (cyclotron)
motion, that can also be accurately modeled by the VA.


title: AC Stark shift of the Cs microwave atomic clock transitions

abstract:
  We analyze the AC Stark shift of the Cs microwave atomic clock transition
theoretically and experimentally. Theoretical and experimental data are in a
good agreement with each other. Results indicate the absence of a magic
wavelength at which there would be no differential shift of the clock states
having zero projections of the total angular momentum.


title:
Quantum Limits and Robustness of Nonlinear Intracavity Absorption
  Spectroscopy

abstract:
  We investigate the limits of intracavity absorption spectroscopy with
nonlinear media. Using a common theoretical framework, we compare the detection
of a trace gas within an undriven cavity with gain near and above threshold, a
driven cavity with gain kept just below threshold, and a cavity driven close to
the saturation point of a saturable absorber. These phase-transition-based
metrology methods are typically quantum-limited by spontaneous emission, and we
compare them to the empty cavity shotnoise-limited case. Although the
fundamental limits achievable with nonlinear media do not surpass the empty
cavity limits, we show that nonlinear methods are more robust against certain
technical noise models. This recognition may have applications in spectrometer
design for devices operating in non-ideal field environments.


title: Driving Currents for Flux Rope Coronal Mass Ejections

abstract:
  We present a method for measuring electrical currents enclosed by flux rope
structures that are ejected within solar coronal mass ejections (CMEs). Such
currents are responsible for providing the Lorentz self-force that propels
CMEs. Our estimates for the driving current are based on measurements of the
propelling force obtained using data from the LASCO coronagraphs aboard the
SOHO satellite. We find that upper limits on the currents enclosed by CMEs are
typically around $10^{10}$ Amperes. We estimate that the magnetic flux enclosed
by the CMEs in the LASCO field of view is a few $\times 10^{21}$ Mx.


title: WSRT Faraday tomography of the Galactic ISM at \lambda ~ 0.86 m

abstract:
  We investigate the properties of the Galactic ISM by applying Faraday
tomography to a radio polarization data set in the direction of the Galactic
anti-centre. We address the problem of missing large-scale structure in our
data, and show that this does not play an important role for the results we
present. The main peak of the Faraday depth spectra in our data set is not
measurably resolved for about 8% of the lines of sight. An unresolved peak
indicates a separation between the regions with Faraday rotation and
synchrotron emission. However, cosmic rays pervade the ISM, and synchrotron
emission would therefore also be produced where there is Faraday rotation. We
suggest that the orientation of the magnetic field can separate the two
effects. By modelling the thermal electron contribution to the Faraday depth,
we map the strength of the magnetic field component along the line of sight.
Polarized point sources in our data set have rotation measures that are
comparable to the Faraday depths of the diffuse emission in our data. Our
Faraday depth maps show narrow canals of low polarized intensity. We conclude
that depolarization over the telescope beam produces at least some of these
canals. Finally, we investigate the properties of one conspicuous region in
this data set and argue that it is created by a decrease in line-of-sight
depolarization compared to its surroundings.


title:
Composition dependence of magnetocaloric effect in Sm1-xSrxMnO3 (x =
  0.3-0.5)

abstract:
  We investigated magnetic and magnetocaloric properties in Sm1-xSrxMnO3 (x =
0.30-0.5). We report a magnetic field driven first-order metamagnetic
transition in the paramagnetic state in x = 0.4 and 0.5 and a second-order
transition in x = 0.3. The highest magnetic entropy (-Sm = 6.2 J/kgK for H = 5
T at T = 125 K) that occurs in x = 0.4 is associated with the metamagnetic
transition resulting from the field-induced growth and coalescence of
ferromagnetic nano clusters preexisting in the paramagnetic state. Our results
suggest that manganites with intrinsic nanoscale phase separation can be
exploited for magnetic refrigeration.


title: How do f-mode Frequencies Change with Solar Radius?

abstract:
  We test the relation between relative f-mode frequency variation and
Lagrangian perturbation in the solar radius obtained by Dziembowski and Goode
(2004) using several pairs of solar models and show that it doesn't hold true
for any of the model pairs we have used. We attempt to derive a better
approximation for the kernel linking the relative frequency changes and the
solar radius variation in the subsurface layers


title: Estimating high-dimensional intervention effects from observational data

abstract:
  We assume that we have observational data generated from an unknown
underlying directed acyclic graph (DAG) model. A DAG is typically not
identifiable from observational data, but it is possible to consistently
estimate the equivalence class of a DAG. Moreover, for any given DAG, causal
effects can be estimated using intervention calculus. In this paper, we combine
these two parts. For each DAG in the estimated equivalence class, we use
intervention calculus to estimate the causal effects of the covariates on the
response. This yields a collection of estimated causal effects for each
covariate. We show that the distinct values in this set can be consistently
estimated by an algorithm that uses only local information of the graph. This
local approach is computationally fast and feasible in high-dimensional
problems. We propose to use summary measures of the set of possible causal
effects to determine variable importance. In particular, we use the minimum
absolute value of this set, since that is a lower bound on the size of the
causal effect. We demonstrate the merits of our methods in a simulation study
and on a data set about riboflavin production.


title:
One-dimensional steady-state structures at relativistic interaction of
  laser radiation with overdense plasma for finite electron temperature

abstract:
  One-dimensional steady-state plasma-field structures in overdense plasma are
studied assuming that the electron temperature is uniform over plasma bulk and
the ions are stationary. It is shown that there may exist solutions for
electron distributions with cavitation regions in plasma under the action of
ponderomotive force


title:
Fefferman-Stein inequalities for the \mathbb{Z}_2^d Dunkl maximal
  operator

abstract:
  In this article, we establish the Fefferman-Stein inequalities for the Dunkl
maximal operator associated with a finite reflection group generated by the
sign changes. Similar results are also given for a large class of operators
related to Dunkl's analysis.


title: Restricted Schur Polynomials and Finite N Counting

abstract:
  Restricted Schur polynomials have been posited as orthonormal operators for
the change of basis from N=4 SYM to type IIB string theory [1,2,3,4]. In this
letter we briefly expound the relationship found between the restricted Schurs
and the operators found by Brown, Heslop and Ramgoolam in [5]. We then briefly
examine the finite N counting of the restricted Schur polynomials.


title: Localization for Linear Stochastic Evolutions

abstract:
  We consider a discrete-time stochastic growth model on the $d$-dimensional
lattice with non-negative real numbers as possible values per site. The growth
model describes various interesting examples such as oriented site/bond
percolation, directed polymers in random environment, time discretizations of
the binary contact path process. We show the equivalence between the slow
population growth and a localization property in terms of "replica overlap".
The main novelty of this paper is that we obtain this equivalence even for
models with positive probability of extinction at finite time. In the course of
the proof, we characterize, in a general setting, the event on which an
exponential martingale vanishes in the limit.


title: Noiseless Quantum Transmission of Information via Aharonov - Bohm Effect

abstract:
  The possibility of quantum transmission of information via the induced
fractional angular momentum by the Aharonov - Bohm vector potential is
revealed. Its special advantage is that it is noiseless: Stray magnetic fields
of environments influence the energy spectrum of the ion, but cannot contribute
the fractional angular momentum to cause noise.


title:
Vertex operator approach for correlation functions of Belavin's
  (Z/nZ)-symmetric model

abstract:
  Belavin's $(\mathbb{Z}/n\mathbb{Z})$-symmetric model is considered on the
basis of bosonization of vertex operators in the $A^{(1)}_{n-1}$ model and
vertex-face transformation. The corner transfer matrix (CTM) Hamiltonian of
$(\mathbb{Z}/n\mathbb{Z})$-symmetric model and tail operators are expressed in
terms of bosonized vertex operators in the $A^{(1)}_{n-1}$ model. Correlation
functions of $(\mathbb{Z}/n\mathbb{Z})$-symmetric model can be obtained by
using these objects, in principle. In particular, we calculate spontaneous
polarization, which reproduces the result by myselves in 1993.


title: Chaos, concentration, and multiple valleys

abstract:
  Disordered systems are an important class of models in statistical mechanics,
having the defining characteristic that the energy landscape is a fixed
realization of a random field. Examples include various models of glasses and
polymers. They also arise in other areas, like fitness models in evolutionary
biology. The ground state of a disordered system is the state with minimum
energy. The system is said to be chaotic if a small perturbation of the energy
landscape causes a drastic shift of the ground state. We present a rigorous
theory of chaos in disordered systems that confirms long-standing physics
intuition about connections between chaos, anomalous fluctuations of the ground
state energy, and the existence of multiple valleys in the energy landscape.
Combining these results with mathematical tools like hypercontractivity, we
establish the existence of the above phenomena in eigenvectors of GUE matrices,
the Kauffman-Levin model of evolutionary biology, directed polymers in random
environment, a subclass of the generalized Sherrington-Kirkpatrick model of
spin glasses, the discrete Gaussian free field, and continuous Gaussian fields
on Euclidean spaces. We also list several open questions.


title:
Search for a light pseudoscalar particle in the decay $K^0_L \to \pi^0
  \pi^0 X$

abstract:
  We performed a search for a light pseudoscalar particle $X$ in the decay
$K_L^0->pi0pi0X$, $X->\gamma\gamma$ with the E391a detector at KEK. Such a
particle with a mass of 214.3 MeV/$c^2$ was suggested by the HyperCP
experiment. We found no evidence for $X$ and set an upper limit on the product
branching ratio for $K_L^0->pi0pi0X$, $X->\gamma\gamma$ of $2.4 \times 10^{-7}$
at the 90% confidence level. Upper limits on the branching ratios in the mass
region of $X$ from 194.3 to 219.3 MeV/$c^2$ are also presented.


title:
Calculation of the nucleon sigma term and strange quark content with two
  flavors of dynamical overlap fermions

abstract:
  We present a calculation of the nucleon sigma term on two-flavor QCD
configurations with dynamical overlap fermions. We analyse the lattice data for
the nucleon mass using the baryon chiral perturbation theory. Using partially
quenched data sets, we extract the connected and disconnected contributions to
the nucleon sigma term separately. Chiral symmetry on the lattice simplifies
the determination of the disconnected contribution. We find that the strange
quark content, which determines the neutralino dark matter reaction rate with
nucleon through the Higgs boson exchange, is much smaller than the previous
lattice results.


title:
Modular elliptic directions with complex multiplication (with an
  application to Gross's elliptic curves)

abstract:
  For every normalized newform f in S_2(Gamma_1(N)) with complex
multiplication, we study the modular parametrizations of elliptic curves C from
the abelian variety A_f. We apply the results obtained when C is Gross's
elliptic curve A(p).