title: Error correcting code using tree-like multilayer perceptron

abstract:
  An error correcting code using a tree-like multilayer perceptron is proposed.
An original message $\mbi{s}^0$ is encoded into a codeword $\boldmath{y}_0$
using a tree-like committee machine (committee tree) or a tree-like parity
machine (parity tree). Based on these architectures, several schemes featuring
monotonic or non-monotonic units are introduced. The codeword $\mbi{y}_0$ is
then transmitted via a Binary Asymmetric Channel (BAC) where it is corrupted by
noise. The analytical performance of these schemes is investigated using the
replica method of statistical mechanics. Under some specific conditions, some
of the proposed schemes are shown to saturate the Shannon bound at the infinite
codeword length limit. The influence of the monotonicity of the units on the
performance is also discussed.

categories: cond-mat.stat-mech cond-mat.dis-nn cs.IT math.IT


title:
Estimation and tests for models satisfying linear constraints with
  unknown parameter

abstract:
  We introduce estimation and test procedures through divergence minimization
for models satisfying linear constraints with unknown parameter. Several
statistical examples and motivations are given. These procedures extend the
empirical likelihood (EL) method and share common features with generalized
empirical likelihood (GEL). We treat the problems of existence and
characterization of the divergence projections of probability measures on sets
of signed finite measures. Our approach allows for a study of the estimates
under misspecification. The asymptotic behavior of the proposed estimates are
studied using the dual representation of the divergences and the explicit forms
of the divergence projections. We discuss the problem of the choice of the
divergence under various respects. Also we handle efficiency and robustness
properties of minimum divergence estimates. A simulation study shows that the
Hellinger divergence enjoys good efficiency and robustness properties.


title: Hidden symmetries and Killing tensors on curved spaces

abstract:
  Higher order symmetries corresponding to Killing tensors are investigated.
The intimate relation between Killing-Yano tensors and non-standard
supersymmetries is pointed out. In the Dirac theory on curved spaces,
Killing-Yano tensors generate Dirac type operators involved in interesting
algebraic structures as dynamical algebras or even infinite dimensional
algebras or superalgebras. The general results are applied to space-times which
appear in modern studies. One presents the infinite dimensional superalgebra of
Dirac type operators on the 4-dimensional Euclidean Taub-NUT space that can be
seen as a twisted loop algebra. The existence of the conformal Killing-Yano
tensors is investigated for some spaces with mixed Sasakian structures.


title: Counting number of factorizations of a natural number

abstract:
  In this note we describe a new method of counting the number of unordered
factorizations of a natural number by means of a generating function and a
recurrence relation arising from it, which improves an earlier result in this
direction.


title:
Universal fermionization of bosons on permutative representations of the
  Cuntz algebra ${\cal O}_{2}$

abstract:
  Bosons and fermions are described by using canonical generators of Cuntz
algebras on any permutative representation. We show a fermionization of bosons
which universally holds on any permutative representation of the Cuntz algebra
${\cal O}_{2}$. As examples, we show fermionizations on the Fock space and the
infinite wedge.


title: Cosmology with minimal length uncertainty relations

abstract:
  We study the effects of the existence of a minimal observable length in the
phase space of classical and quantum de Sitter (dS) and Anti de Sitter (AdS)
cosmology. Since this length has been suggested in quantum gravity and string
theory, its effects in the early universe might be expected. Adopting the
existence of such a minimum length results in the Generalized Uncertainty
Principle (GUP), which is a deformed Heisenberg algebra between minisuperspace
variables and their momenta operators. We extend these deformed commutating
relations to the corresponding deformed Poisson algebra in the classical limit.
Using the resulting Poisson and Heisenberg relations, we then construct the
classical and quantum cosmology of dS and Ads models in a canonical framework.
We show that in classical dS cosmology this effect yields an inflationary
universe in which the rate of expansion is larger than the usual dS universe.
Also, for the AdS model it is shown that GUP might change the oscillatory
nature of the corresponding cosmology. We also study the effects of GUP in
quantized models through approximate analytical solutions of the Wheeler-DeWitt
(WD) equation, in the limit of small scale factor for the universe, and compare
the results with the ordinary quantum cosmology in each case.


title: Note on Generalized Janus Configurations

abstract:
  We study several aspects of generalized Janus configuration, which includes a
theta term. We investigate the vacuum structure of the theory and find that
unlike the Janus configuration without theta term there is no nontrivial
vacuum. We also discuss BPS soliton configuration both by supersymmetry
analysis and from energy functional. The half BPS configurations could be
realized by introducing transverse (p,q)-strings in original brane
configuration corresponding to generalized Janus configuration. It turns out
the BPS soliton could be taken as modified dyon. We discuss the solution of
half BPS equations for the sharp interface case. Moreover we construct less
supersymmetric Janus configuration with theta term.


title: New anti-perovskite-type Superconductor ZnNyNi3

abstract:
  We have synthesized a new superconductor ZnNyNi3 with Tc ~3 K. The crystal
structure has the same anti-perovskite-type such as MgCNi3 and CdCNi3. As far
as we know, this is the third superconducting material in Ni-based
anti-perovskite series. For this material, superconducting parameters,
lower-critical field Hc1(0), upper-critical field Hc2(0), coherence length
x(0), penetration depth l(0), and Gintzburg -Landau parameter k(0) have been
experimentally determined.


title: Review on recent developments in jet finding

abstract:
  We review recent developments related to jet clustering algorithms and jet
finding. These include fast implementations of sequential recombination
algorithms, new IRC safe algorithms, quantitative determination of jet areas
and quality measures for jet finding, among many others. We also briefly
discuss the status of jet finding in heavy ion collisions, where full QCD jets
have been measured for the first time at RHIC.


title:
Soft-lubrication effect on the lateral migration of a slightly deformed
  bubble rising near a vertical plane wall

abstract:
  Deformation-induced lateral migration of a bubble slowly rising near a
vertical plane wall in a stagnant liquid is numerically and theoretically
investigated. In particular, our focus is set on a situation with a small
clearance $c$ between the bubble interface and the wall. Motivated by the fact
that experimentally measured migration velocity (Takemura et al. (2002, J.
Fluid Mech. {\bf 461}, 277)) is higher than the velocity estimated by the
available analytical solution (Magnaudet et al. (2003, J. Fluid Mech. {\bf
476}, 115)) using the Fax\'{e}n mirror image technique for $\kappa(=a/(a+c))\ll
1$ (here $a$ is the bubble radius), when the clearance parameter
$\epsilon(=c/a)$ is comparable to or smaller than unit, the numerical analysis
based on the boundary-fitted finite-difference approach by solving the Stokes
equation is performed to complement the experiment. To improve the
understandings of a role of the squeezing flow within the bubble-wall gap, the
theoretical analysis based on a soft-lubrication approach (Skotheim & Mahadevan
(2004, Phys. Rev. Lett. {\bf 92}, 245509)) is also performed. The present
analyses demonstrate the migration velocity scales $\propto{\rm Ca}\
\epsilon^{-1}V_{B1}$ (here, $V_{B1}$ and ${\rm Ca}$ denote the rising velocity
and the capillary number, respectively) in the limit of $\epsilon\to 0$.


title: Spin-injection Hall effect in a planar photovoltaic cell

abstract:
  Successful incorporation of the spin degree of freedom in semiconductor
technology requires the development of a new paradigm allowing for a scalable,
non-destructive electrical detection of the spin-polarization of injected
charge carriers as they propagate along the semiconducting channel. In this
paper we report the observation of a spin-injection Hall effect (SIHE) which
exploits the quantum-relativistic nature of spin-charge transport and which
meets all these key requirements on the spin detection. The two-dimensional
electron-hole gas photo-voltaic cell we designed to observe the SIHE allows us
to develop a quantitative microscopic theory of the phenomenon and to
demonstrate its direct application in optoelectronics. We report an
experimental realization of a non-magnetic spin-photovoltaic effect via the
SIHE, rendering our device an electrical polarimeter which directly converts
the degree of circular polarization of light to a voltage signal.


title: Room temperature ferromagnetism in carbon-implanted ZnO

abstract:
  Unexpected ferromagnetism has been observed in carbon doped ZnO films grown
by pulsed laser deposition [Phys. Rev. Lett. 99, 127201 (2007)]. In this
letter, we introduce carbon into ZnO films by ion implantation. Room
temperature ferromagnetism has been observed. Our analysis demonstrates that
(1) C-doped ferromagnetic ZnO can be achieved by an alternative method, i.e.
ion implantation, and (2) the chemical involvement of carbon in the
ferromagnetism is indirectly proven.


title:
Sub-terahertz, microwaves and high energy emissions during the December
  6, 2006 flare, at 18:40 UT

abstract:
  The presence of a solar burst spectral component with flux density increasing
with frequency in the sub-terahertz range, spectrally separated from the
well-known microwave spectral component, bring new possibilities to explore the
flaring physical processes, both observational and theoretical. The solar event
of 6 December 2006, starting at about 18:30 UT, exhibited a particularly
well-defined double spectral structure, with the sub-THz spectral component
detected at 212 and 405 GHz by SST and microwaves (1-18 GHz) observed by the
Owens Valley Solar Array (OVSA). Emissions obtained by instruments in
satellites are discussed with emphasis to ultra-violet (UV) obtained by the
Transition Region And Coronal Explorer (TRACE), soft X-rays from the
Geostationary Operational Environmental Satellites (GOES) and X- and gamma-rays
from the Ramaty High Energy Solar Spectroscopic Imager (RHESSI). The sub-THz
impulsive component had its closer temporal counterpart only in the higher
energy X- and gamma-rays ranges. The spatial positions of the centers of
emission at 212 GHz for the first flux enhancement were clearly displaced by
more than one arc-minute from positions at the following phases. The observed
sub-THz fluxes and burst source plasma parameters were found difficult to be
reconciled to a purely thermal emission component. We discuss possible
mechanisms to explain the double spectral components at microwaves and in the
THz ranges.


title: Localized magnetic states in biased bilayer and trilayer graphene

abstract:
  We study the localized magnetic states of impurity in biased bilayer and
trilayer graphene. It is found that the magnetic boundary for bilayer and
trilayer graphene presents the mixing features of Dirac and conventional
fermion. For zero gate bias, as the impurity energy approaches the Dirac point,
the impurity magnetization region diminishes for bilayer and trilayer graphene.
When a gate bias is applied, the dependence of impurity magnetic states on the
impurity energy exhibits a different behavior for bilayer and trilayer graphene
due to the opening of a gap between the valence and the conduction band in the
bilayer graphene with the gate bias applied. The magnetic moment and the
corresponding magnetic transition of the impurity in bilayer graphene are also
investigated.


title: Faster Approximate String Matching for Short Patterns

abstract:
  We study the classical approximate string matching problem, that is, given
strings $P$ and $Q$ and an error threshold $k$, find all ending positions of
substrings of $Q$ whose edit distance to $P$ is at most $k$. Let $P$ and $Q$
have lengths $m$ and $n$, respectively. On a standard unit-cost word RAM with
word size $w \geq \log n$ we present an algorithm using time $$ O(nk \cdot
\min(\frac{\log^2 m}{\log n},\frac{\log^2 m\log w}{w}) + n) $$ When $P$ is
short, namely, $m = 2^{o(\sqrt{\log n})}$ or $m = 2^{o(\sqrt{w/\log w})}$ this
improves the previously best known time bounds for the problem. The result is
achieved using a novel implementation of the Landau-Vishkin algorithm based on
tabulation and word-level parallelism.


title:
Frequency-dependent reflection of spin waves from a magnetic
  inhomogeneity induced by a surface DC-current

abstract:
  The reflectivity of a highly localized magnetic inhomogeneity is
experimentally studied. The inhomogeneity is created by a dc-current carrying
wire placed on the surface of a ferrite film. The reflection of propagating
dipole-dominated spin-wave pulses is found to be strongly dependent on the
spin-wave frequency if the current locally increases the magnetic field. In the
opposite case the frequency dependence is negligible.


title: Dynamic System Adaptation by Constraint Orchestration

abstract:
  For Paradigm models, evolution is just-in-time specified coordination
conducted by a special reusable component McPal. Evolution can be treated
consistently and on-the-fly through Paradigm's constraint orchestration, also
for originally unforeseen evolution. UML-like diagrams visually supplement such
migration, as is illustrated for the case of a critical section solution
evolving into a pipeline architecture.


title: Grounded Uniaxial Material Slabs as Magnetic Conductors

abstract:
  The objective of this paper is all-angle artificial magnetic conductor, i.e.
artificial magnetic conductor that has stable magnetic-wall effect with respect
to the incidence angle. Furthermore, we seek for a design that would be easy
for manufacturing. In order to achieve this we use grounded uniaxial material
slabs and we do not constrict ourselves to naturally available materials.
Instead, we assume that the desired parameters can be synthesized using the
emerging artificial electromagnetic materials. It is found that it is possible
to have an all-angle magnetic-wall effect for both TE and TM polarization.
Especially for the TM fields the structure would be easily manufacturable. The
proposed structure has similar appearance as more well-known artificial
impedance surfaces, but the design parameters and the physical properties
behind the magnetic wall effect are novel. The performance of the proposed
artificial magnetic conductor is verified with numerical simulations. This
paper introduces a new approach how to obtain a magnetic-wall effect. It is
possible to use this this approach also together with other ways of obtaining
the magnetic-wall effect for dual-band operation.


title: Quantum Lift of Non-BPS Flat Directions

abstract:
  We study N=2, d=4 attractor equations for the quantum corrected two-moduli
prepotential $\mathcal{F}=st^2+i\lambda$, with $\lambda$ real, which is the
only correction which preserves the axion shift symmetry and modifies the
geometry. In the classical case the black hole effective potential is known to
have a flat direction. We found that in the presence of D0-D6 branes the black
hole potential exhibits a flat direction in the quantum case as well. It
corresponds to non-BPS $Z\neq 0$ solutions to the attractor equations. Unlike
the classical case, the solutions acquire non-zero values of the axion field.
For the cases of D0-D4 and D2-D6 branes the classical flat direction reduces to
separate critical points which turn out to have a vanishing axion field.


title:
New light on the driving mechanism in roAp stars. Part I. Effects of
  metallicity

abstract:
  Observations suggest that a relationship exists between the driving mechanism
of roAp star pulsations and the heavy element distribution in these stars. We
attempt to study the effects of local and global metallicity variations on the
excitation mechanism of high order p-modes in A star models. We developed
stellar evolutionary models to describe magnetic A stars with different global
metallicity or local metal accumulation profiles. These models were computed
with CLES ("Code Li\`egeois d'\'evolution stellaire"), and the stability of our
models was assessed with the non-adiabatic oscillation code MAD. Our models
reproduce the blue edge of the roAp star instability strip, but generate a red
edge hotter than the observed one, regardless of metallicity. Surprisingly, we
find that an increase in opacity inside the driving region can produce a lower
amount of driving, which we refer to as the "inverse $\kappa$-mechanism".


title:
Sufficient conditions on observability grammian for synchronization in
  arrays of coupled time-varying linear systems

abstract:
  Synchronizability of stable, output-coupled, identical, time-varying linear
systems is studied. It is shown that if the observability grammian satisfies a
persistence of excitation condition, then there exists a bounded, time-varying
linear feedback law that yields exponential synchronization for all fixed,
asymmetrical interconnections with connected graphs. Also, a weaker condition
on the grammian is given for asymptotic synchronization. No assumption is made
on the strength of coupling. Moreover, related to the main problem, a
particular array of output-coupled systems that is pertinent to much-studied
consensus problems is investigated. In this array, the individual systems are
integrators with identical, time-varying, symmetric positive semi-definite
output matrices. Trajectories of this array are shown to stay bounded using a
time-invariant, quadratic Lyapunov function. Also, sufficient conditions on
output matrix for synchronization are provided. All of the results in the paper
are generated for both continuous time and discrete time.


title: First evidence for Casimir scaling in G(2) lattice gauge theory

abstract:
  Potentials between static quarks and antiquarks from a few lowest
representations were evaluated in numerical simulations of 4-dimensional pure
G$_2$ lattice gauge theory at various couplings. The obtained potentials are
linearly rising at intermediate distances and their string tensions exhibit
(approximate) Casimir scaling. This result is in accordance with a model of the
vacuum of non-Abelian gauge theories with a domain structure, in which the
(color) magnetic flux randomly fluctuates within a domain, but the total flux
in each domain is quantized in units of the gauge group center.


title: Course of lectures on physical constructivism

abstract:
  In this course, I talk about the source of mathematical constructivism and
its role in the future development of theoretical physics. I describe what
physical constructivism is and why it is necessary for the penetration of exact
methods of theoretical physics to the area of complex systems, which formally
belong to the others natural disciplines. I describe the concrete heuristic for
the creating of models of constructive quantum theory the method of collective
behavior. I represent the constructive viewpoint on the quantum computer, which
treats it as the model object of many particle quantum physics, and the
practical recommendation concerning its building. Due to the known inertia of
the educational system constructive methods in mathematics remains mostly
unknown to the wide physical community, and I hope that this course will
stimulate the interest to the new possibilities, which these methods open.
These possibilities represent interest to natural scientists and for
programmers as well.


title:
Kernel Regression by Mode Calculation of the Conditional Probability
  Distribution

abstract:
  The most direct way to express arbitrary dependencies in datasets is to
estimate the joint distribution and to apply afterwards the argmax-function to
obtain the mode of the corresponding conditional distribution. This method is
in practice difficult, because it requires a global optimization of a
complicated function, the joint distribution by fixed input variables. This
article proposes a method for finding global maxima if the joint distribution
is modeled by a kernel density estimation. Some experiments show advantages and
shortcomings of the resulting regression method in comparison to the standard
Nadaraya-Watson regression technique, which approximates the optimum by the
expectation value.


title: Pivots, Determinants, and Perfect Matchings of Graphs

abstract:
  We give a characterization of the effect of sequences of pivot operations on
a graph by relating it to determinants of adjacency matrices. This allows us to
deduce that two sequences of pivot operations are equivalent iff they contain
the same set S of vertices (modulo two). Moreover, given a set of vertices S,
we characterize whether or not such a sequence using precisely the vertices of
S exists. We also relate pivots to perfect matchings to obtain a
graph-theoretical characterization. Finally, we consider graphs with self-loops
to carry over the results to sequences containing both pivots and local
complementation operations.


title:
Merger of Massive Black Holes using N-Body Simulations with
  Post-Newtonian Corrections

abstract:
  We present preliminary results from self-consistent, high resolution direct
{\it N}-body simulations of massive black hole binaries in mergers of galactic
nuclei. The dynamics of the black hole binary includes the full Post-Newtonian
corrections (up to 2.5PN) to its equations of motion. We show that massive
black holes starting at separations of 100 pc can evolve down to
gravitational-wave-induced coalescence in less than a Hubble time. The
binaries, in our models, often form with very high eccentricity and, as a
result, reach separations of 50 Schwarzschild radius with eccentricities which
are clearly distinct from zero -- even though gravitational wave emission damps
the eccentricity during the inspiral. These deviations from exact circular
orbits, at such small separations, may have important consequences for LISA
data analysis.


title:
SERpredict: Detection of tissue- or tumor-specific isoforms generated
  through exonization of transposable elements

abstract:
  Background: Transposed elements (TEs) are known to affect transcriptomes,
because either new exons are generated from intronic transposed elements (this
is called exonization), or the element inserts into the exon, leading to a new
transcript. Several examples in the literature show that isoforms generated by
an exonization are specific to a certain tissue (for example the heart muscle)
or inflict a disease. Thus, exonizations can have negative effects for the
transcriptome of an organism. Results: As we aimed at detecting other tissue-
or tumor-specific isoforms in human and mouse genomes which were generated
through exonization of a transposed element, we designed the automated analysis
pipeline SERpredict (SER = Specific Exonized Retroelement) making use of
Bayesian Statistics. With this pipeline, we found several genes in which a
transposed element formed a tissue- or tumor-specific isoform. Conclusion: Our
results show that SERpredict produces relevant results, demonstrating the
importance of transposed elements in shaping both the human and the mouse
transcriptomes. The effect of transposed elements on the human transcriptome is
several times higher than the effect on the mouse transcriptome, due to the
contribution of the primate-specific Alu elements


title: Finiteness for the k-factor model and chirality varieties

abstract:
  This paper deals with two families of algebraic varieties arising from
applications. First, the k-factor model in statistics, consisting of n-times-n
covariance matrices of n observed Gaussian variables that are pairwise
independent given k hidden Gaussian variables. Second, chirality varieties
inspired by applications in chemistry. A point in such a chirality variety
records chirality measurements of all k-subsets among an n-set of ligands. Both
classes of varieties are given by a parameterisation, while for applications
having polynomial equations would be desirable. For instance, such equations
could be used to test whether a given point lies in the variety. We prove that
in a precise sense, which is different for the two classes of varieties, these
equations are finitely characterisable when k is fixed and n grows.


title: XXZ-like phase in the F-AF anisotropic Heisenberg chain

abstract:
  By means of the Density Matrix Renormalization Group technique, we have
studied the region where $XXZ$-like behavior is most likely to emerge within
the phase diagram of the F-AF anisotropic extended ($J-J'$) Heisenberg chain.
We have analyzed, in great detail, the equal-time two-spin correlation
functions, both in- and out-of- plane, as functions of the distance (and
momentum). Then, we have extracted, through an accurate fitting procedure, the
exponents of the asymptotic power-law decay of the spatial correlations. We
have used the exact solution of $XXZ$ model ($J'=0$) to benchmark our results,
which clearly show the expected agreement. A critical value of $J'$ has been
found where the relevant power-law decay exponent is independent of the
in-plane nearest-neighbor coupling.


title:
The origin of abundance gradients in the Milky Way: the predictions of
  different models

abstract:
  We aim at studying the abundance gradients along the Galactic disk and their
dependence upon several parameters: a threshold in the surface gas density
regulating star formation, the star formation efficiency, the timescale for the
formation of the thin disk and the total surface mass density of the stellar
halo. We test a model which considers a cosmological infall law. This law does
not predict an inside-out disk formation, but it allows to well fit the
properties of the solar vicinity. We study several cases. We find that to
reproduce at the same time the abundance, star formation rate and surface gas
density gradients along the Galactic disk it is necessary to assume an
inside-out formation for the disk. The threshold in the gas density is not
necessary and the same effect could be reached by assuming a variable star
formation efficiency. A cosmologically derived infall law with an inside-out
process for the disk formation and a variable star formation efficiency can
indeed well reproduce all the properties of the disk. However, the cosmological
model presented here does not have sufficient resolution to capture the
requested inside-out formation for the disk.


title:
Production of fragments with and without strangeness within a combined
  BUU+SMM approach

abstract:
  The formation of hypernuclei in hadron-induced reactions and in heavy-ion
collisions within a combination of a covariant transport model and a
statistical fragmentation approach is investigated. We study the applicability
and limitations of such a hybrid approach by comparing fragmentation data in
heavy-ion collisions and proton induced reactions. It turns out that the
combined approach describes fairly well multiplicities and momentum spectra of
fragments. We thus extend the model by including strangeness degrees of freedom
in the fragmentation process, modeled by a phase-space coalescence method. We
provide theoretical predictions on spectra and on inclusive cross sections of
light hypernuclei for the future experiments on hypernuclear physics at the new
GSI facility.


title:
Biased exonization of transposed elements in duplicated genes: A lesson
  from the TIF-IA gene

abstract:
  Background: Gene duplication and exonization of intronic transposed elements
are two mechanisms that enhance genomic diversity. We examined whether there is
less selection against exonization of transposed elements in duplicated genes
than in single-copy genes. Results: Genome-wide analysis of exonization of
transposed elements revealed a higher rate of exonization within duplicated
genes relative to single-copy genes. The gene for TIF-IA, an RNA polymerase I
transcription initiation factor, underwent a humanoid-specific triplication,
all three copies of the gene are active transcriptionally, although only one
copy retains the ability to generate the TIF-IA protein. Prior to TIF-IA
triplication, an Alu element was inserted into the first intron. In one of the
non-protein coding copies, this Alu is exonized. We identified a single point
mutation leading to exonization in one of the gene duplicates. When this
mutation was introduced into the TIF-IA coding copy, exonization was activated
and the level of the protein-coding mRNA was reduced substantially. A very low
level of exonization was detected in normal human cells. However, this
exonization was abundant in most leukemia cell lines evaluated, although the
genomic sequence is unchanged in these cancerous cells compared to normal
cells. Conclusion: The definition of the Alu element within the TIF-IA gene as
an exon is restricted to certain types of cancers; the element is not exonized
in normal human cells. These results further our understanding of the delicate
interplay between gene duplication and alternative splicing and of the
molecular evolutionary mechanisms leading to genetic innovations. This implies
the existence of purifying selection against exonization in single copy genes,
with duplicate genes free from such constrains.


title:
Transduplication resulted in the incorporation of two protein-coding
  sequences into the Turmoil-1 transposable element of C. elegans

abstract:
  Transposable elements may acquire unrelated gene fragments into their
sequences in a process called transduplication. Transduplication of
protein-coding genes is common in plants, but is unknown of in animals. Here,
we report that the Turmoil-1 transposable element in C. elegans has
incorporated two protein-coding sequences into its inverted terminal repeat
(ITR) sequences. The ITRs of Turmoil-1 contain a conserved RNA recognition
motif (RRM) that originated from the rsp- 2 gene and a fragment from the
protein-coding region of the cpg-3 gene. We further report that an open reading
frame specific to C. elegans may have been created as a result of a Turmoil-1
insertion. Mutations at the 5' splice site of this open reading frame may have
reactivated the transduplicated RRM motif


title: Specific heat anomalies of open quantum systems

abstract:
  The evaluation of the specific heat of an open, damped quantum system is a
subtle issue. One possible route is based on the thermodynamic partition
function which is the ratio of the partition functions of system plus bath and
of the bath alone. For the free damped particle it has been shown, however,
that the ensuing specific heat may become negative for appropriately chosen
environments. Being an open system this quantity then naturally must be
interpreted as the change of the specific heat obtained as the difference
between the specific heat of the heat bath coupled to the system degrees of
freedom and the specific heat of the bath alone. While this difference may
become negative, the involved specific heats themselves are always positive;
thus, the known thermodynamic stability criteria are perfectly guaranteed. For
a damped quantum harmonic oscillator, instead of negative values, under
appropriate conditions one can observe a dip in the difference of specific
heats as a function of temperature. Stylized minimal models containing a single
oscillator heat bath are employed to elucidate the occurrence of the anomalous
temperature dependence of the corresponding specific heat values. Moreover, we
comment on the consequences for the interpretation of the density of states
based on the thermal partitionfunction.


title:
Comparative analysis of transposed element insertion within human and
  mouse genomes reveals Alu's unique role in shaping the human transcriptome

abstract:
  Background: Transposed elements (TEs) have a substantial impact on mammalian
evolution and are involved in numerous genetic diseases. We compared the impact
of TEs on the human transcriptome and the mouse transcriptome. Results: We
compiled a dataset of all TEs in the human and mouse genomes, identifying
3,932,058 and 3,122,416 TEs, respectively. We than extracted TEs located within
human and mouse genes and, surprisingly, we found that 60% of TEs in both human
and mouse are located in intronic sequences, even though introns comprise only
24% of the human genome. All TE families in both human and mouse can exonize.
TE families that are shared between human and mouse exhibit the same percentage
of TE exonization in the two species, but the exonization level of Alu, a
primatespecific retroelement, is significantly greater than that of other TEs
within the human genome, leading to a higher level of TE exonization in human
than in mouse (1,824 exons compared with 506 exons, respectively). We detected
a primate-specific mechanism for intron gain, in which Alu insertion into an
exon creates a new intron located in the 3' untranslated region (termed
'intronization'). Finally, the insertion of TEs into the first and last exons
of a gene is more frequent in human than in mouse, leading to longer exons in
human. Conclusion: Our findings reveal many effects of TEs on these two
transcriptomes. These effects are substantially greater in human than in mouse,
which is due to the presence of Alu elements in human.


title:
A solvable model which has X(5) as a limiting symmetry and removes some
  inherent drawbacks

abstract:
  Solvable Hamiltonians for the $\beta$ and $\gamma$ intrinsic shape
coordinates are proposed. The eigenfunctions of the $\gamma$ Hamiltonian are
spheroidal periodic functions, while the Hamiltonian for the $\beta$ degree of
freedom involves the Davidson's potential and admits eigenfunctions which can
be expressed in terms of the generalized Legendre polynomials. The proposed
model goes to X(5) in the limit of $|\gamma|$-small. Some drawbacks of the X(5)
model, as are the eigenfunction periodicity and the $\gamma$ Hamiltonian
hermiticity, are absent in the present approach. Results of numerical
applications to $^{150}$Nd, $^{154}$Gd and $^{192}$Os are in good agreement to
the experimental data. Comparison with X(5) calculations suggests that the
present approach provides a quantitative better description of the data. This
is especially true for the excitation energies in the gamma band.


title: LFV in Models with A4 Flavour Symmetry

abstract:
  The approximated tri-bimaximal mixing observed in the neutrino oscillations
is a particular feature of a class of models characterized by the spontaneously
broken horizontal flavour symmetry A4. In this paper, it is presented an
analysis on the predictions of these models for relevant low-energy
observables. In an effective operator approach, these effects are dominated by
dim-6 operators, suppressed by the scale M of new physics. Indications for M
and an upper bound on \theta_{13} of a few percent are found.


title:
TranspoGene and microTranspoGene: transposed elements influence on the
  transcriptome of seven vertebrates and invertebrates

abstract:
  Transposed elements (TEs) are mobile genetic sequences. During the evolution
of eukaryotes TEs were inserted into active protein-coding genes, affecting
gene structure, expression and splicing patterns, and protein sequences.
Genomic insertions of TEs also led to creation and expression of new functional
non-coding RNAs such as micro- RNAs. We have constructed the TranspoGene
database, which covers TEs located inside proteincoding genes of seven species:
human, mouse, chicken, zebrafish, fruit fly, nematode and sea squirt. TEs were
classified according to location within the gene: proximal promoter TEs,
exonized TEs (insertion within an intron that led to exon creation), exonic TEs
(insertion into an existing exon) or intronic TEs. TranspoGene contains
information regarding specific type and family of the TEs, genomic and mRNA
location, sequence, supporting transcript accession and alignment to the TE
consensus sequence. The database also contains host gene specific data: gene
name, genomic location, Swiss-Prot and RefSeq accessions, diseases associated
with the gene and splicing pattern. In addition, we created microTranspoGene: a
database of human, mouse, zebrafish and nematode TEderived microRNAs. The
TranspoGene and micro- TranspoGene databases can be used by researchers
interested in the effect of TE insertion on the eukaryotic transcriptome.


title: The Alternative Choice of Constitutive Exons throughout Evolution

abstract:
  Alternative cassette exons are known to originate from two processes
exonization of intronic sequences and exon shuffling. Herein, we suggest an
additional mechanism by which constitutively spliced exons become alternative
cassette exons during evolution. We compiled a dataset of orthologous exons
from human and mouse that are constitutively spliced in one species but
alternatively spliced in the other. Examination of these exons suggests that
the common ancestors were constitutively spliced. We show that relaxation of
the 59 splice site during evolution is one of the molecular mechanisms by which
exons shift from constitutive to alternative splicing. This shift is associated
with the fixation of exonic splicing regulatory sequences (ESRs) that are
essential for exon definition and control the inclusion level only after the
transition to alternative splicing. The effect of each ESR on splicing and the
combinatorial effects between two ESRs are conserved from fish to human. Our
results uncover an evolutionary pathway that increases transcriptome diversity
by shifting exons from constitutive to alternative splicing


title: Intronic Alus Influence Alternative Splicing

abstract:
  Examination of the human transcriptome reveals higher levels of RNA editing
than in any other organism tested to date. This is indicative of extensive
double-stranded RNA (dsRNA) formation within the human transcriptome. Most of
the editing sites are located in the primate-specific retrotransposed element
called Alu. A large fraction of Alus are found in intronic sequences, implying
extensive Alu-Alu dsRNA formation in mRNA precursors. Yet, the effect of these
intronic Alus on splicing of the flanking exons is largely unknown. Here, we
show that more Alus flank alternatively spliced exons than constitutively
spliced ones; this is especially notable for those exons that have changed
their mode of splicing from constitutive to alternative during human evolution.
This implies that Alu insertions may change the mode of splicing of the
flanking exons. Indeed, we demonstrate experimentally that two Alu elements
that were inserted into an intron in opposite orientation undergo base-pairing,
as evident by RNA editing, and affect the splicing patterns of a downstream
exon, shifting it from constitutive to alternative. Our results indicate the
importance of intronic Alus in influencing the splicing of flanking exons,
further emphasizing the role of Alus in shaping of the human transcriptome


title: Clues to unveil the emitter in LS 5039: powerful jets vs colliding winds

abstract:
  LS 5039 is among the most interesting VHE sources in the Galaxy. Two
scenarios have been put forward to explain the observed TeV radiation: jets vs
pulsar winds. The source has been detected during the superior conjunction of
the compact object, when very large gamma-ray opacities are expected. In
addition, electromagnetic cascades, which may make the system more transparent
to gamma-rays, are hardly efficient for realistic magnetic fields in massive
star surroundings. All this makes unlikely the standard pulsar scenario for LS
5039, in which the emitter is the region located between the star and the
compact object, where the opacities are the largest. Otherwise, a jet-like flow
can transport energy to regions where the photon-photon absorption is much
lower and the TeV radiation is not so severely absorbed.


title: Multiplicative Aspects of the Halperin-Carlsson Conjecture

abstract:
  We use the multiplicative structure of the Koszul resolution to give short
and simple proofs of some known estimates for the total dimension of the
cohomology of spaces which admit free torus actions and analogous results for
filtered differential modules over polynomial rings. We also point out the
possibility of improving these results in the presence of a multiplicative
structure on the so-called minimal Hirsch-Brown model for the equivariant
cohomology of the space.


title: A unified Pietsch domination theorem

abstract:
  In this paper we prove an abstract version of Pietsch's domination theorem
which unify a number of known Pietsch-type domination theorems for classes of
mappings that generalize the ideal of absolutely p-summing linear operators. A
final result shows that Pietsch-type dominations are totally free from
algebraic conditions, such as linearity, multilinearity, etc.


title: Is the ejection of the corona a general phenomenon in microquasars?

abstract:
  We study the evolution of some microquasars during their outbursts as
observed with the X-ray telescopes RXTE and INTEGRAL. We focus on the interplay
between the accretion disc, and the medium responsible for the production of
the hard X-rays (the so-called corona). By comparing the behaviour of two
sources (XTE J1550-564 and GRS 1915+105) at X-ray energies and radio
wavelengths, we propose a scenario in which the discrete ejections are
triggered in coincidence with soft X-ray peaks during the outburst. We also
suggest, in those two sources, that the ejected material is the corona that is
seen to disappear in coincidence with the X-ray maxima. We then turn to two
other sources, XTE J1748-248, and XTE J1859+226, and study whether the same
conclusions can be drawn from the existing multi-wave length (radio+X-ray)
data.


title: Gas Phase diagnostics of Protoplanetary disk extension

abstract:
  We investigate the potential of using ratios of fine structure and
near-infrared forbidden line transitions of atomic carbon to diagnose
protoplanetary disk extension. Using results from 2D photoionisation and
radiative transfer modeling of a realistic protoplanetary disk structure
irradiated by X-rays from a T Tauri star, we obtain theoretical emission maps
from which we construct radial distributions of the strongest emission lines
produced in the disk. We show that ratios of fine structure to near-infrared
forbidden line emission of atomic carbon are especially promising to constrain
the minimum size of gaseous protoplanetary disks. While theoretically viable,
the method presents a number of observational difficulties that are also
discussed here.


title: Craig Interpolation for Quantifier-Free Presburger Arithmetic

abstract:
  Craig interpolation has become a versatile algorithmic tool for improving
software verification. Interpolants can, for instance, accelerate the
convergence of fixpoint computations for infinite-state systems. They also help
improve the refinement of iteratively computed lazy abstractions. Efficient
interpolation procedures have been presented only for a few theories. In this
paper, we introduce a complete interpolation method for the full range of
quantifier-free Presburger arithmetic formulas. We propose a novel convex
variable projection for integer inequalities and a technique to combine them
with equalities. The derivation of the interpolant has complexity low-degree
polynomial in the size of the refutation proof and is typically fast in
practice.


title: Flips and variation of moduli schemes of sheaves on a surface

abstract:
  Let $H$ be an ample line bundle on a non-singular projective surface $X$, and
$M(H)$ the coarse moduli scheme of rank-two $H$-semistable sheaves with fixed
Chern classes on $X$. We show that if $H$ changes and passes through walls to
get closer to $K_X$, then $M(H)$ undergoes natural flips with respect to
canonical divisors. When $X$ is minimal and its Kodaira dimension is positive,
this sequence of flips terminates in $M(H_X)$; $H_X$ is an ample line bundle
lying so closely to $K_X$ that the canonical divisor of $M(H_X)$ is nef. Remark
that so-called Thaddeus-type flips somewhat differ from flips with respect to
canonical divisors.


title: Carbon and Nitrogen Abundances in Early-type Galaxies

abstract:
  For the first time, we undertake a systematic examination of the nitrogen
abundances for a sample of 35 early-type galaxies spanning a range of masses
and local environment. The nitrogen-sensitive molecular feature at 3360\AA has
been employed in conjunction with a suite of atomic- and molecular-sensitive
indices to provide unique and definitive constraints on the chemical content of
these systems. By employing NH3360, we are now able to break the carbon,
nitrogen, and oxygen degeneracies inherent to the use of the CN-index. We
demonstrate that the NH3360 feature shows little dependency upon the velocity
dispersion (our proxy for mass) of the galaxies, contrary to what is seen for
carbon- and magnesium-sensitive indices. At face value, these results are at
odds with conclusions drawn previously using indices sensitive to both carbon
and nitrogen, such as cyanogen (CN). With the aid of stellar population models,
we find that the N/Fe ratios in these galaxies are consistent with being
mildly-enhanced with respect to the solar ratio. We also explore the dependence
of these findings upon environment, by analyzing the co-added spectra of
galaxies in the field and the Coma cluster. We confirm the previously found
differences in carbon abundances between galaxies in low- and high-density
environments, while showing that these differences do not seem to exist for
nitrogen. We discuss the implications of these findings for the derivation of
the star formation histories in early-type galaxies, and for the origin of
carbon and nitrogen, themselves.


title: Non Abelian Chern-Simons-Higgs solutions in (2+1) dimensions

abstract:
  Non Abelian vortices of a SU(2) Chern-Simons--Higgs theory in 2+1 dimensions
are constructed numerically. They represent natural counterparts of the U(1)
solutions considered by Hong, Kim and Pac, and, by Jackiw and Weinberg. The
Abelian embeddings are identified, for all values of the Higgs selfinteraction
strength $\nu$, resulting in both attractive and repulsive phases. A detailed
analysis of the properties of the solutions reveals the existence ofa number of
unexpected features. For a certain range of the parameter $\nu$, it is shown
that the non Abelian vortices have lower energy than their topologically stable
Abelian counterparts, resulting in an effective energy lower bound on the SU(2)
configurations. The angular momentum of these vortices is analysed and it is
found that unlike the Abelian ones, whose angular momentum and energy are
unrelated, there is a nontrivial mass--spin relation of the non Abelian
vortices.


title:
Kinetic study of the oxide-assisted catalyst-free synthesis of silicon
  nitride nanowires

abstract:
  The synthesis of Si3N4 nanowires from the reaction of silicon nanoparticles
with N2 in the 1200-1440 C temperature range is reported. The nitridation
conditions are such that the reaction with nitrogen is favoured by the presence
of silicon oxide in the particles and by the active oxidation of silicon
without a catalyst. It is shown that the Si to Si3N4 conversion rate depends on
the amount of silicon particles used in the experiments and that, in general,
the reaction slows down for greater amounts. This trend is explained by
particle stacking, which restricts the exchange of gases between the furnace
atmosphere and the atmosphere around the inner particles. In a first stage,
local oxygen partial pressure increases around the inner particles and inhibits
nitridation locally. If the amount of reactant Si nanoparticles is small
enough, this extrinsic effect is avoided and the intrinsic nitridation kinetics
can be measured. Experiments show that intrinsic kinetics does not depend on
temperature.


title: Status of indirect searches in the PAMELA and Fermi era

abstract:
  The detection of gamma-rays, antiprotons and positrons due to pair
annihilation of dark matter particles in the Milky Way halo is a viable
indirect technique to search for signatures of supersymmetric dark matter where
the major challenge is the discrimination of the signal from the background
generated by standard production mechanisms. The new PAMELA antiproton data are
consistent with the standard secondary production and this allows us to
constrain exotic contribution to the spectrum due to neutralino annihilations.
In particular, we show that in the framework of minimal supergravity (mSUGRA),
in a clumpy halo scenario (with clumpiness factor > 10) and for large values of
tan(beta)> 55, almost all the parameter space allowed by WMAP is excluded.
  Instead, the PAMELA positron fraction data exhibit an excess that cannot be
explained by secondary production. PPB-BETS and ATIC reported a feature in
electron spectrum at a few hundred GeV. The excesses seem to be consistent and
imply a source, conventional or exotic, of additional leptonic component. Here
we discuss the status of indirect dark matter searches and a perspective
forPAMELA and Fermi gamma-ray space telescope (Fermi) experiments.


title: 3D spectroscopy of candidate double-barred lenticular galaxies

abstract:
  Significant fraction of barred galaxies hosts secondary bar-like structures
on optical and NIR images. The circumnuclear dynamics of double-barred objects
are still not well understood, observational data concerning kinematics are
incomplete and inconsistent. In order to compare the simulations results with
observations, we have started new spectroscopic studying of stellar kinematics
in lenticular galaxies from Peter Erwin's catalog of secondary bars. We present
first results concerning their stellar kinematics based on the observations
performed with the integral-field spectrograph MPFS at the Russian 6-m
telescope.


title:
Variational Theory of Hot Nucleon Matter II : Spin-Isospin Correlations
  and Equation of State of Nuclear and Neutron Matter

abstract:
  We apply the variational theory for fermions at finite temperature and high
density, developed in an earlier paper, to symmetric nuclear matter and pure
neutron matter. This extension generalizes to finite temperatures, the many
body technique used in the construction of the zero temperature
Akmal-Pandharipande-Ravenhall equation of state. We discuss how the formalism
can be used for practical calculations of hot dense matter. Neutral pion
condensation along with the associated isovector spin longitudinal sum rule is
analyzed. The equation of state is calculated for temperatures less than 30 MeV
and densities less than three times the saturation density of nuclear matter.
The behavior of the nucleon effective mass in medium is also discussed.


title:
Dark matter and dark energy proposals: maintaining cosmology as a true
  science?

abstract:
  I consider the relation of explanations for the observed data to testability
in the following contexts: observational and experimental detection of dark
matter; observational and experimental detection of dark energy or a
cosmological constant $\Lambda$; observational or experimental testing of the
multiverse proposal to explain a small non-zero value of $\Lambda$; and
observational testing of the possibility of large scale spatial inhomogeneity
with zero $\Lambda$.


title: Conditions for synchronizability in arrays of coupled linear systems

abstract:
  Synchronization control in arrays of identical output-coupled continuous-time
linear systems is studied. Sufficiency of new conditions for the existence of a
synchronizing feedback law are analyzed. It is shown that for neutrally stable
systems that are detectable form their outputs, a linear feedback law exists
under which any number of coupled systems synchronize provided that the
(directed, weighted) graph describing the interconnection is fixed and
connected. An algorithm generating one such feedback law is presented. It is
also shown that for critically unstable systems detectability is not
sufficient, whereas full-state coupling is, for the existence of a linear
feedback law that is synchronizing for all connected coupling configurations.


title: Algebraic methods in random matrices and enumerative geometry

abstract:
  We review the method of symplectic invariants recently introduced to solve
matrix models loop equations, and further extended beyond the context of matrix
models. For any given spectral curve, one defined a sequence of differential
forms, and a sequence of complex numbers Fg . We recall the definition of the
invariants Fg, and we explain their main properties, in particular symplectic
invariance, integrability, modularity,... Then, we give several example of
applications, in particular matrix models, enumeration of discrete surfaces
(maps), algebraic geometry and topological strings, non-intersecting brownian
motions,...


title: Some results on dynamical black holes

abstract:
  We give indications that outer future trapping horizons play a role in the
particular semi-classical instability of an evolving black hole that produces
the Hawking's radiation. These are obtained with the use of the Hamilton-Jacobi
tunneling method. It automatically selects one special expression for the
surface gravity of a changing horizon, the one defined a decade ago by Hayward
using Kodama's theory of spherically symmetric gravitational fields. The method
also applies to point masses embedded in an expanding universe and to general,
spherically symmetric black holes.


title: Meson supercurrents and the Meissner effect in the Sakai-Sugimoto model

abstract:
  The Sakai-Sugimoto model provides a holographic description for chiral
symmetry breaking. We use this model to investigate chirally broken phases in
an external magnetic field at finite isospin and baryon chemical potentials.
The equations of motion for the bulk gauge fields are solved analytically and
the free energy is computed from the Yang-Mills and Chern-Simons contributions
to the D8 brane action. In the case of a neutral pion condensate, a magnetic
field is found to induce nonzero gradients of the Goldstone boson fields
corresponding to meson supercurrents. A charged pion condensate, on the other
hand, expels the magnetic field due to the Meissner effect. Upon comparing the
Gibbs free energies of these two phases we find that the rotation of the chiral
condensate into a charged pion condensate for finite isospin chemical
potentials is partially undone by switching on a magnetic field, and we
determine the critical magnetic field which removes the charged pion condensate
in a first-order phase transition.


title:
SO(n + 1) Symmetric Solutions of the Einstein Equations in Higher
  Dimensions

abstract:
  A method of solving the Einstein equations with a scalar field is presented.
It is applied to find higher dimensional vacuum metrics invariant under the
group SO(n + 1) acting on n-dimensional spheres.


title: Galaxy systems in the optical and infrared

abstract:
  In these three lectures a review is provided of the properties of galaxy
systems as determined from optical and infrared measurements. Covered topics
are: clusters identification, global cluster properties and their scaling
relations, cluster internal structure and dynamics, and properties of cluster
galaxy populations.


title:
Analyse de la rigidit\'e des machines outils 3 axes d'architecture
  parall\`ele hyperstatique

abstract:
  The paper presents a new stiffness modelling method for overconstrained
parallel manipulators, which is applied to 3-d.o.f. translational mechanisms.
It is based on a multidimensional lumped-parameter model that replaces the link
flexibility by localized 6-d.o.f. virtual springs. In contrast to other works,
the method includes a FEA-based link stiffness evaluation and employs a new
solution strategy of the kinetostatic equations, which allows computing the
stiffness matrix for the overconstrained architectures and for the singular
manipulator postures. The advantages of the developed technique are confirmed
by application examples, which deal with comparative stiffness analysis of two
translational parallel manipulators.


title: Many Light Higgs Bosons in the NMSSM

abstract:
  The next-to-minimal supersymmetric model with a light doublet-like
  CP-odd Higgs boson and small $\tan \beta$ can satisfy all experimental limits
on Higgs bosons even with light superpartners. In these scenarios, the two
lightest CP-even Higgs bosons, $\hi$ and $\hii$, and the charged Higgs boson,
$\hp$, can all be light enough to be produced at LEP and yet have decays that
have not been looked for or are poorly constrained by existing collider
experiments. The channel $\hi\to \ai\ai$ (where $\ai$ is the lightest CP-odd
boson and has mass below $2m_b$) with $\ai\to \tau^+\tau^-$ or $2j$ is still
awaiting LEP constraints for $\mhi>86\gev$ or $82\gev$, respectively. LEP data
may also contain $\epem\to \hii\ai$ events where $\hii\to Z\ai$ is the dominant
decay, a channel that was never examined. Decays of the charged Higgs bosons
are often dominated by $H^\pm \to W^{\pm (\star)} \ai$ with $\ai \to gg,c \bar
c, \tau^+ \tau^-$. This is a channel that has so far been ignored in the search
for $t\to \hp b$ decays at the Tevatron. A specialized analysis might reveal a
signal. The light $\ai$ might be within the reach of $B$ factories via
$\Upsilon\to \gamma \ai$ decays. We study typical mass ranges and branching
ratios of Higgs bosons in this scenario and compare these scenarios where the
$\ai$ has a large doublet component to the more general scenarios with
arbitrary singlet component for the $\ai$.


title: Stochastic evolutionary game dynamics

abstract:
  In this review, we summarize recent developments in stochastic evolutionary
game dynamics of finite populations.


title:
Contribution of Two-Boson-Exchange with $\Delta(1232)$ Excitation to
  Parity-Violating Elastic Electron-Proton Scattering

abstract:
  We study the leading electroweak corrections in the precision measurement of
the strange form factors. Specifically, we calculate the two-boson-exchange
(TBE), two-photon-exchange (TPE) plus $\gamma Z$-exchange ($\gamma Z$E),
corrections with $\Delta(1232)$ excitation to the parity-violating asymmetry of
the elastic electron-proton scattering. The interplay between nucleon and
$\Delta$ contributions is found to depend strongly on the kinematics, as
$\delta_\Delta$ begins as negligible at backward angles but becomes very large
and negative and dominant at forward angles, while $\delta_N$ always stays
positive and decreases monotonically with increasing $\epsilon$. The total TBE
corrections to the extracted values of $G^{s}_{E}+\beta G^{s}_{M}$ in recent
experiments of HAPPEX and G0 are, depending on kinematics, found to be large
and range between 13% to -75% but small in the case of A4 experiments.


title: A Review of the Magnitudes of the CKM Matrix Elements

abstract:
  Flavour mixing is described within the Standard Model by the
Cabibbo-Kobayashi-Maskawa matrix elements. With the increasingly higher
statistics collected by many experiments, the matrix elements are measured with
improved precision, allowing for more stringent tests of the Standard Model. In
this paper, a review of the current status of the absolute values of the CKM
matrix elements is presented, with particular attention to the latest
measurements.


title:
Three Dimensional Line Transfer Study of Energy Sources in Compact
  Molecular Gas in Active Galaxies -- AGN/Starburst Connection --

abstract:
  Recent observations suggest molecular line ratios in millimeter and
submillimeter bands may be a good tool to reveal the long-standing question on
the origin of energy sources in obscured active galaxies -- AGN and/or
starburst. Observations of actual molecular medium show in general
inhomogeneous structures as well as high-resolution hydrodynamic simulations
do. In order for precise interpretation of emergent line emission from the
inhomogeneous molecular gas to probe the dominant energy source of active
galaxies, we study characteristic features of emergent intensities via
three-dimensional non-LTE (non-local thermodynamic equilibrium) line transfer
simulations. Our results succeeded in making clear 1) the necessary conditions
for HCN/HCO$^{+}$-dichotomy, and 2) importance of clumpiness on intensity ratio
and its interpretation. These results are obtained for the first time by our
realistic three-dimensional simulations, and line transfer simulations will be
a powerful tool to comprehensive studies of extragalactic interstellar medium
(ISM) in forthcoming ALMA (Atacama Large Millimeter/submillimeter Array) era.


title: Ab initio self-consistent laser theory and random lasers

abstract:
  We review our recent work leading to steady-state solutions of the
semiclassical (Maxwell-Bloch) equations of a laser. These are coupled
non-linear partial differential equations in space and time which have
previously been solved either by fully time-dependent numerical simulations or
by using major approximations which neglect non-linear modal interactions
and/or the openness of the laser system. We have found a time-independent
technique for determining these stationary solutions which can treat lasers of
arbitrary complexity and degree of openness. Our method has been shown to agree
with time-dependent numerical solutions to high accuracy and has been applied
to find the electric field patterns (lasing modes) of random lasers, which lack
a laser cavity and are so strongly damped that the linear system has no
detectable resonances. Our work provides a link between an important non-linear
wave system and the field of quantum/wave chaos in linear systems.


title: Map Lattices coupled by collisions

abstract:
  We introduce a new coupled map lattice model in which the weak interaction
takes place via rare "collisions". By "collision" we mean a strong (possibly
discontinuous) change in the system. For such models we prove uniqueness of the
SRB measure and exponential space-time decay of correlations.


title: The complexity of certain Specht modules for the symmetric group

abstract:
  During the 2004-2005 academic year the VIGRE algebra research group at the
University of Georgia computed the complexities of certain Specht modules
S^\lambda for the symmetric group, using the computer algebra program Magma.
The complexity of an indecomposable module does not exceed the p-rank of the
defect group of its block. The Georgia group conjectured that, generically, the
complexity of a Specht module attains this maximal value; that it is smaller
precisely when the Young diagram of $\lambda$ is built out of $p \times p$
blocks. We prove one direction of this conjecture by showing these Specht
modules do indeed have less than maximal complexity. It turns out that this
class of partitions, which has not previously appeared in the literature,
arises naturally as the solution to a question about the $p$-weight of
partitions and branching.


title:
Numerical Study of Current-Induced Domain-Wall Dynamics: Crossover from
  Spin Transfer to Momentum Transfer

abstract:
  We study current-induced dynamics of a magnetic domain wall by solving a
time-dependent Schr\"{o}dinger equation combined with Landau-Lifshitz-Gilbert
equation in a one-dimensional electron system coupled to localized spins. Two
types of domain-wall motions are observed depending on the hard-axis
anisotropy, $K_{\perp}$, of the localized spin system. For small values of
$K_{\perp}$, the magnetic domain wall shows a streaming motion driven by spin
transfer. In contrast, for large values of $K_{\perp}$, a stick-slip motion
driven by momentum transfer is obtained. We clarify the origin of these
characters of domain-wall motions in terms of the dynamics of one-particle
energy levels and distribution functions.


title: On the Existence of $U$-Polygons of Class $c\geq 4$ in Planar Point Sets

abstract:
  For a finite set $U$ of directions in the Euclidean plane, a convex
non-degenerate polygon $P$ is called a $U$-polygon if every line parallel to a
direction of $U$ that meets a vertex of $P$ also meets another vertex of $P$.
We characterize the numbers of edges of $U$-polygons of class $c\geq4$ with all
their vertices in certain subsets of the plane and derive explicit results in
the case of cyclotomic model sets.


title: Atomic toposes and countable categoricity

abstract:
  We give a model-theoretic characterization of the class of geometric theories
classified by an atomic topos having enough points; in particular, we show that
every complete geometric theory classified by an atomic topos is countably
categorical. Some applications are also discussed.


title:
Topological characterization of flow structures in resistive
  pressure-gradient-driven turbulence

abstract:
  Visualization of turbulent flows is a powerful tool to help understand the
turbulence dynamics and induced transport. However, it does not provide a
quantitative description of the observed structures. In this paper, an approach
to characterize quantitatively the topology of the flows is given. The
technique, which can be applied to any type of turbulence dynamics, is
illustrated through the example of resistive ballooning instabilities.


title: Thermodynamics of the frustrated ferromagnetic spin-1/2 Heisenberg chain

abstract:
  We studied the thermodynamics of the one-dimensional J1-J2 spin-1/2
Heisenberg chain for ferromagnetic nearest-neighbor bonds J1 < 0 and
frustrating antiferromagnetic next-nearest-neighbor bonds J1 > 0 using full
diagonalization of finite rings and a second-order Green-function formalism.
Thereby we focus on J2 < |J1|/4 where the ground state is still ferromagnetic,
but the frustration influences the thermodynamic properties. We found that
their critical indices are not changed by J2. The analysis of the
low-temperature behavior of the susceptibility chi leads to the conclusion that
this behavior changes from chi \propto T^{-2} at J2 < |J1|/4 to chi \propto
T^{-3/2} at the quantum-critical point J2=|J1|/4. Another effect of the
frustration is the appearance of an extra low-T maximum in the specific heat
C_v(T) for J2 \gtrsim |J1|/8, indicating its strong influence on the low-energy
spectrum.


title: Spectral signature of short attosecond pulse trains

abstract:
  We report experimental measurements of high-order harmonic spectra generated
in Ar using a carrier-envelope-offset (CEO) stabilized 12 fs, 800nm laser field
and a fraction (less than 10%) of its second harmonic. Additional spectral
peaks are observed between the harmonic peaks, which are due to interferences
between multiple pulses in the train. The position of these peaks varies with
the CEO and their number is directly related to the number of pulses in the
train. An analytical model, as well as numerical simulations, support our
interpretation.


title: A Note on Coincidence Isometries of Modules in Euclidean Space

abstract:
  It is shown that the coincidence isometries of certain modules in Euclidean
$n$-space can be decomposed into a product of at most $n$ coincidence
reflections defined by their non-zero elements. This generalizes previous
results obtained for lattices to situations that are relevant in
quasicrystallography.


title: On the residual dependence index of elliptical distributions

abstract:
  The residual dependence index of bivariate Gaussian distributions is
determined by the correlation coefficient. This tail index is of certain
statistical importance when extremes and related rare events of bivariate
samples with asymptotic independent components are being modeled. In this paper
we calculate the partial residual dependence indices of a multivariate
elliptical random vector assuming that the associated random radius is in the
Gumbel max-domain of attraction. Furthermore, we discuss the estimation of
these indices when the associated random radius possesses a Weibull-tail
distribution.


title: Meson spectrum and tetraquarks through an AdS/QCD inspired potential

abstract:
  AdS/QCD correspondence allows to compute the quark-antiquark potential in the
static limit. We use this piece of information together with the Salpeter
equation (Schroedinger equation with relativistic kinematics) and a short range
hyperfine splitting potential to describe the bound states of quark-antiquark.
Comparison with experiment permits to fit the parameters of the model, namely
the quark masses and the quark potential parameters. A discussion of heavy
tetraquark masses, prompted by the hypothesis of a diquark-antidiquark
structure for the puzzling state X(3872), is also presented.


title:
Likelihood method and Fisher information in construction of physical
  models

abstract:
  The subjects of the paper are the likelihood method (LM) and the expected
Fisher information (FI) considered from the point od view of the construction
of the physical models which originate in the statistical description of
phenomena. The master equation case and structural information principle are
derived. Then, the phenomenological description of the information transfer is
presented. The extreme physical information (EPI) method is reviewed. As if
marginal, the statistical interpretation of the amplitude of the system is
given. The formalism developed in this paper would be also applied in quantum
information processing and quantum game theory.


title: Explanation of the activity sensitivity of Mn I 5394.7 \AA

abstract:
  There is a long-standing controversy concerning the reason why the Mn I
5394.7 A line in the solar irradiance spectrum brightens more at larger
activity than most other photospheric lines. The claim that this activity
sensitivity is caused by spectral interlocking to chromospheric emission in Mg
II h & k is disputed.
  Classical one-dimensional modeling is used for demonstration; modern
three-dimensional MHD simulation for verification and analysis.
  The Mn I 5394.7 A line thanks its unusual sensitivity to solar activity to
its hyperfine structure. This overrides the thermal and granular Doppler
smearing through which the other, narrower, photospheric lines lose such
sensitivity. We take the nearby Fe I 5395.2 A line as example of the latter and
analyze the formation of both lines in detail to demonstrate and explain
granular Doppler brightening. We show that this affects all narrow lines.
Neither the chromosphere nor Mg II h & k play a role, nor is it correct to
describe the activity sensitivity of Mn I 5394.7 A through plage models with
outward increasing temperature contrast.
  The Mn I 5394.7 A line represents a proxy diagnostic of strong-field magnetic
concentrations in the deep solar photosphere comparable to the G band and the
blue wing of H-alpha, but not a better one than these. The Mn I lines are more
promising as diagnostic of weak fields in high-resolution Stokes polarimetry.


title:
The outer regions of galaxy clusters: Chandra constraints on the X-ray
  surface brightness

abstract:
  (Abridged version) We study the properties of the X-ray surface brightness
profiles in a sample of galaxy clusters that were observed with Chandra and
have emission detectable with a signal-to-noise ratio higher than 2 at a radius
beyond R500 ~ 0.7 R200. Our study aims to measure the slopes of the X-ray
surface brightness and of the gas density profiles in the outskirts of massive
clusters. These constraints are compared to similar results obtained from
observations and numerical simulations of the temperature and dark matter
density profiles with the intention of presenting a consistent picture of the
outer regions of galaxy clusters. We extract the surface brightness profiles
Sb(r) of 52 X-ray luminous galaxy clusters at z>0.3 from X-ray exposures
obtained with Chandra. We estimate R200 using both a beta-model that reproduces
Sb(r) and scaling relations from the literature. The two methods converge to
comparable values. We determine the radius, R_S2N, at which the signal-to-noise
ratio is larger than 2 and select the objects in the sample that satisfy the
criterion R_S2N/R200 > 0.7. For the eleven selected objects, we model with a
power-law the behaviour of Sb(r). We measure a consistent steepening of the
Sb(r) profile moving outward from 0.4 R200, where an average slope of -3.6
(sigma=0.8) is estimated. At R200, we evaluate a slope of -4.3 (sigma=0.9) that
implies a slope in the gas density profile of -2.6 and a predicted mean value
of the surface brightness in the 0.5-2 band of 2e-12 erg/s/cm2/deg2. Combined
with estimates of the outer slope of the gas temperature profile and
expectations about the dark matter distribution, these measurements allow us to
describe properly how X-ray luminous clusters behave out to the virial radius.


title: Parameters of Herbig Ae/Be and Vega-type stars

abstract:
  This work presents the determination of the effective temperature, gravity,
metallicity, mass, luminosity and age of 27 young early-type stars, most of
them in the age range 1-10 Myr, and three -suspected- hot companions of post-T
Tauri stars belonging to the Lindroos binary sample. Most of these objects show
IR excesses in their spectral energy distributions, which are indicative of the
presence of disks. The work is relevant in the fields of stellar physics,
physics of disks and formation of planetary systems.
  Spectral energy distributions and mid-resolution spectra were used to
estimate the effective temperature. The comparison of the profiles of the
Balmer lines with synthetic profiles provides the value of the stellar gravity.
High-resolution optical observations and synthetic spectra are used to estimate
the metallicity, [M/H]. Once these three parameters are known for each star,
evolutionary tracks and isochrones provide estimations of the mass, luminosity,
age and distance (or upper limits in some cases). The method is original in the
sense that it is distance-independent, i.e. the estimation of the stellar
parameters does not require, as it happens in other works, the knowledge of the
distance to the object. A detailed discussion on some individual objects, in
particular VV Ser, RR Tau, 49 Cet and the three suspected hot companions of
post-T Tauris, is presented. The paper also shows the difficulty posed by the
morphology and behaviour of the system star+disk in the computation of the
stellar parameters.


title:
The distribution of ejected subhalos and its implication for halo
  assembly bias

abstract:
  Using a high-resolution cosmological $N$-body simulation, we identify the
ejected population of subhalos, which are halos at redshift $z=0$ but were once
contained in more massive `host' halos at high redshifts. The fraction of the
ejected subhalos in the total halo population of the same mass ranges from 9%
to 4% for halo masses from $\sim 10^{11}$ to $\sim 10^{12}\msun$. Most of the
ejected subhalos are distributed within 4 times the virial radius of their
hosts. These ejected subhalos have distinct velocity distribution around their
hosts in comparison to normal halos. The number of subhalos ejected from a host
of given mass increases with the assembly redshift of the host. Ejected
subhalos in general reside in high-density regions, and have a much higher bias
parameter than normal halos of the same mass. They also have earlier assembly
times, so that they contribute to the assembly bias of dark matter halos seen
in cosmological simulations. However, the assembly bias is {\it not} dominated
by the ejected population, indicating that large-scale environmental effects on
normal halos are the main source for the assembly bias.


title: Note on the X_(1)-Laguerre orthogonal polynomials

abstract:
  This note supplements the work of Gomez-Ullate, Kamran and Milson on the
X_(1)-Laguerre polynomials which are orthogonal in a weighted Hilbert function
space on the positive half-line of the real line. These polynomials are
generated by a second-order ordinary linear differential equation with a
spectral parameter. Some additional information on the Sturm-Liouville form of
this equation is given in this note, together with details of the singular
differential operators generated in the weighted Hilbert function space. In
particular, structured boundary conditions are given to determine the special
self-adjoint operator, whose discrete spectrum and associated eigenvectors
yield the X_(1)-Laguerre polynomials.


title:
Nuclear State Preparation via Landau-Zener-Stueckelberg transitions in
  Double Quantum Dots

abstract:
  We theoretically model a nuclear-state preparation scheme that increases the
coherence time of a two-spin qubit in a double quantum dot. The two-electron
system is tuned repeatedly across a singlet-triplet level-anticrossing with
alternating slow and rapid sweeps of an external bias voltage. Using a
Landau-Zener-Stueckelberg model, we find that in addition to a small nuclear
polarization that weakly affects the electron spin coherence, the slow sweeps
are only partially adiabatic and lead to a weak nuclear spin measurement and a
nuclear-state narrowing which prolongs the electron spin coherence. This
resolves some open problems brought up by a recent experiment [D. J. Reilly et
al., Science 321, 817 (2008).]. Based on our description of the weak
measurement, we simulate a system with up to n=200 nuclear spins per dot.
Scaling in n indicates a stronger effect for larger n.


title:
Observation of spatial quantum correlations induced by multiple
  scattering of non-classical light

abstract:
  We present the experimental realization of spatial quantum correlations of
photons that are induced by multiple scattering of squeezed light. The quantum
correlation relates photons propagating along two different light trajectories
through the random medium and is infinite in range. Both positive and negative
spatial quantum correlations are observed when varying the quantum state
incident to the multiple scattering medium, and the magnitude of the
correlations is controlled by the number of photons. The experimental results
are in excellent agreement with recent theoretical proposals by implementing
the full quantum model of multiple scattering.


title: Langevin's `Twin Paradox' paper revisited

abstract:
  An in-depth and mathematically-detailed analysis of Langevin's popular 1911
article on the special theory of relativity is presented. For the reader's
convenience, English translations of large parts of the original French text
are given. The self-contradictory nature of many of Langevin's assertions is
pointed out. Of special interest is the analysis of the exchange of light
signals between the travelling and stay-at-home twins in Langevin's thought
experiment, in which antinomies are found in the conventional relativistic
treatment. Their resolution shows that the physical basis of the differential
aging effect in the experiment is not `length contraction', as in the
conventional interpretation, but instead the application of the correct
relative velocity transformation formula. The spurious nature of the correlated
`length contraction' and `relativity of simultaneity' effects of conventional
special relativity is also demonstrated. In consequence, an argument given,
claiming to demonstrate that an upper limit of $c$ on the speed of any physical
signal is required by causality, is invalid. Its conclusion is also in
contradiction with astronomical observations and the results of a recent
experiment.


title:
A Real Space Description of Magnetic Field Induced Melting in the Charge
  Ordered Manganites: I. The Clean Limit

abstract:
  We study the melting of charge order in the half doped manganites using a
model that incorporates double exchange, antiferromagnetic superexchange, and
Jahn-Teller coupling between electrons and phonons. We primarily use a real
space Monte Carlo technique to study the phase diagram in terms of applied
field $(h)$ and temperature $(T)$, exploring the melting of charge order with
increasing $h$ and its recovery on decreasing $h$. We observe hysteresis in
this response, and discover that the `field melted' high conductance state can
be spatially inhomogeneous even without extrinsic disorder. The hysteretic
response plays out in the background of field driven equilibrium phase
separation. Our results, exploring $h$, $T$, and the electronic parameter
space, are backed up by analysis of simpler limiting cases and a Landau
framework for the field response. This paper focuses on our results in the
`clean' systems, a companion paper studies the effect of cation disorder on the
melting phenomena.


title:
Properties of WNh stars in the Small Magellanic Cloud: evidence for
  homogeneous evolution

abstract:
  We derive the physical properties of three WNh stars in the SMC to constrain
stellar evolution beyond the main sequence at low metallicity and to
investigate the metallicity dependence of the clumping properties of massive
stars. We compute atmosphere models to derive the stellar and wind properties
of the three WNh targets. A FUV/UV/optical/near-infrared analysis gives access
to temperatures, luminosities, mass loss rates, terminal velocities and stellar
abundances. All stars still have a large hydrogen mass fraction in their
atmosphere, and show clear signs of CNO processing in their surface abundances.
One of the targets can be accounted for by normal stellar evolution. It is a
star with initial mass around 40-50 Msun in, or close to, the core He burning
phase. The other two objects must follow a peculiar evolution, governed by fast
rotation. In particular, one object is likely evolving homogeneously due to its
position blue-ward of the main sequence and its high H mass fraction. The
clumping factor of one star is found to be 0.15+/-0.05. This is comparable to
values found for Galactic Wolf-Rayet stars, indicating that within the
uncertainties, the clumping factor does not seem to depend on metallicity.


title:
Tuning the Correlation Decay in the Resistance Fluctuations of
  Multi-Species Networks

abstract:
  A new network model is proposed to describe the $1/f^\alpha$ resistance noise
in disordered materials for a wide range of $\alpha$ values ($0< \alpha < 2$).
More precisely, we have considered the resistance fluctuations of a thin
resistor with granular structure in different stationary states: from nearly
equilibrium up to far from equilibrium conditions. This system has been
modelled as a network made by different species of resistors, distinguished by
their resistances, temperature coefficients and by the energies associated with
thermally activated processes of breaking and recovery. The correlation
behavior of the resistance fluctuations is analyzed as a function of the
temperature and applied current, in both the frequency and time domains. For
the noise frequency exponent, the model provides $0< \alpha < 1$ at low
currents, in the Ohmic regime, with $\alpha$ decreasing inversely with the
temperature, and $1< \alpha <2$ at high currents, in the non-Ohmic regime.
Since the threshold current associated with the onset of nonlinearity also
depends on the temperature, the proposed model qualitatively accounts for the
complicate behavior of $\alpha$ versus temperature and current observed in many
experiments. Correspondingly, in the time domain, the auto-correlation function
of the resistance fluctuations displays a variety of behaviors which are tuned
by the external conditions.


title:
On the plasma temperature in supernova remnants with cosmic-ray modified
  shocks

abstract:
  Context: Multiwavelength observations of supernova remnants can be explained
within the framework of the diffusive shock acceleration theory, which allows
effective conversion of the explosion energy into cosmic rays. Although the
models of nonlinear shocks describe reasonably well the nonthermal component of
emission, certain issues, including the heating of the thermal plasma and the
related X-ray emission, remain still open.
  Aims: To discuss how the evolution and structure of supernova remnants is
affected by strong particle acceleration at the forward shock.
  Methods: Analytical estimates combined with detailed discussion of the
physical processes.
  Results: The overall dynamics is shown to be relatively insensitive to the
amount of particle acceleration, but the post-shock gas temperature can be
reduced to a relatively small multiple, even as small as six times, the ambient
temperature with a very weak dependence on the shock speed. This is in marked
contrast to pure gas models where the temperature is insensitive to the ambient
temperature and is determined by the square of the shock speed. It thus appears
to be possible to suppress effectively thermal X-ray emission from remnants by
strong particle acceleration. This might provide a clue for understanding the
lack of thermal X-rays from the TeV bright supernova remnant RX J1713.7-3946.


title: Noncommutative epsilon-graded connections

abstract:
  We introduce the new notion of epsilon-graded associative algebras which
takes its root into the notion of commutation factors introduced in the context
of Lie algebras. We define and study the associated notion of
epsilon-derivation-based differential calculus, which generalizes the
derivation-based differential calculus on associative algebras. A corresponding
notion of noncommutative connection is also defined. We illustrate these
considerations with various examples of epsilon-graded algebras, in particular
some graded matrix algebras and the Moyal algebra. This last example permits
also to interpret mathematically a noncommutative gauge field theory.


title: Two Strange Constructions in the Euclidean Plane

abstract:
  We present two new constructions in the usual euclidean plane. We only deal
with 'Grecian Geometry', with this phrase we mean elementary geometry in the
two-dimensional space R 2 . We describe and prove two propositions about
'projections'. The proofs need only elementary analytical knowledge.


title: Two-Dimensional Gauge Theory and Matrix Model

abstract:
  We study a matrix model obtained by dimensionally reducing Chern-Simon theory
on S^3. We find that the matrix integration is decomposed into sectors
classified by the representation of SU(2). We show that the N-block sectors
reproduce SU(N) Yang-Mills theory on S^2 as the matrix size goes to infinity.


title:
Dynamical Schwinger effect and high-intensity lasers. Realising
  nonperturbative QED

abstract:
  We consider the possibility of experimental verification of vacuum e^+e^-
pair creation at the focus of two counter-propagating optical laser beams with
intensities 10^{20}-10^{22} W/cm^2, achievable with present-day petawatt
lasers, and approaching the Schwinger limit: 10^{29} W/cm^2 to be reached at
ELI. Our approach is based on the collisionless kinetic equation for the
evolution of the e^+ and e^- distribution functions governed by a non-Markovian
source term for pair production. As possible experimental signals of vacuum
pair production we consider e^+e^- annihilation into gamma-pairs and the
refraction of a high-frequency probe laser beam by the produced e^+e^- plasma.
We discuss the dependence of the dynamical pair production process on laser
wavelength, with special emphasis on applications in the X-ray domain (X-FEL),
as well as the prospects for \mu^+\mu^- and \pi^+\pi^- pair creation at
high-intensity lasers. We investigate perspectives for using high-intensity
lasers as ``boosters'' of ion beams in the few-GeV per nucleon range, which is
relevant, e.g., to the exploration of the QCD phase transition in laboratory
experiments.

categories: physics.plasm-ph hep-ph nucl-th physics.optics


title:
Random matrix model for antiferromagnetism and superconductivity on a
  two-dimensional lattice

abstract:
  We suggest a new mean field method for studying the thermodynamic competition
between magnetic and superconducting phases in a two-dimensional square
lattice. A partition function is constructed by writing microscopic
interactions that describe the exchange of density and spin-fluctuations. A
block structure dictated by spin, time-reversal, and bipartite symmetries is
imposed on the single-particle Hamiltonian. The detailed dynamics of the
interactions are neglected and replaced by a normal distribution of random
matrix elements. The resulting partition function can be calculated exactly.
The thermodynamic potential has a structure which depends only on the spectrum
of quasiparticles propagating in fixed condensation fields, with coupling
constants that can be related directly to the variances of the microscopic
processes. The resulting phase diagram reveals a fixed number of phase
topologies whose realizations depend on a single coupling-parameter ratio,
alpha. Most phase topologies are realized for a broad range of values of alpha
and can thus be considered robust with respect to moderate variations in the
detailed description of the underlying interactions.


title: Half integer features in the quantum Hall Effect: experiment and theory

abstract:
  The quantum Hall effect is one of the most important developments in
condensed matter physics of the 20th century. The standard explanations of the
famous integer quantized Hall plateaus in the transverse resistivity are
qualitative, and involve assumptions about disorder, localized states, extended
states, edge states, Fermi levels pinned by Landau levels, etc. These standard
narratives give plausible reasons for the existence of the plateaus, but
provide little in the way of even a qualitative understanding of the shape and
width of the Hall plateaus, much less a first principles calculation. The
injection model presented in this paper changes that situation. Rather than
focusing on the middle of the Hall device, we follow the electrons to their
source: one corner of the Hall bar and its steep electric field gradients. We
find the entire resistivity curve including the Hall plateaus is calculable as
a function of magnetic field, temperature, and current. The new higher current
experiments reported here show remarkable half integer features for the first
time; these are faithfully reproduced by the injection theory. The Hall
plateaus and half integer inflections are shown to result from the local
density of states appropriate to the magnetic field and the strong electric
field gradient at the injection corner.


title: Particle-acceleration timescales in TeV blazar flares

abstract:
  Observations of minute-scale flares in TeV Blazars place constraints on
particle acceleration mechanisms in those objects. The implications for a
variety of radiation mechanisms have been addressed in the literature; in this
paper we compare four different acceleration mechanisms: diffusive shock
acceleration, second-order Fermi, shear acceleration and the converter
mechanism. When the acceleration timescales and radiative losses are taken into
account, we can exclude shear acceleration and the neutron-based converted
mechanism as possible acceleration processes in these systems. The first-order
Fermi process and the converter mechanism working via SSC photons are still
practically instantaneous, however, provided sufficient turbulence is generated
on the timescale of seconds. We propose stochastic acceleration as a promising
candidate for the energy-dependent time delays in recent gamma-ray flares of
Markarian 501.


title: Small-correlation expansions for the inverse Ising problem

abstract:
  We present a systematic small-correlation expansion to solve the inverse
Ising problem: find a set of couplings and fields corresponding to a given set
of correlations and magnetizations. Couplings are calculated up to the third
order in the correlations for generic magnetizations, and to the seventh order
in the case of zero magnetizations; in addition we show how to sum some useful
classes of diagrams exactly. The resulting expansion outperforms existing
algorithms on the Sherrington-Kirkpatrick spin-glass model.


title:
Si3N4 single-crystal nanowires grown from silicon micro and
  nanoparticles near the threshold of passive oxidation

abstract:
  A simple and most promising oxide-assisted catalyst-free method is used to
prepare silicon nitride nanowires that give rise to high yield in a short time.
After a brief analysis of the state of the art, we reveal the crucial role
played by the oxygen partial pressure: when oxygen partial pressure is slightly
below the threshold of passive oxidation, a high yield inhibiting the formation
of any silica layer covering the nanowires occurs and thanks to the synthesis
temperature one can control nanowire dimensions.


title: Semiuniform semigroups and convolution

abstract:
  Semiuniform semigroups provide a natural setting for the convolution of
generalized finite measures on semigroups. A semiuniform semigroup is said to
be ambitable if each uniformly bounded uniformly equicontinuous set of
functions on the semigroup is contained in an ambit. In the convolution
algebras constructed over ambitable semigroups, topological centres have a
tractable characterization.


title:
Absence of Breakdown of the Poisson Hypothesis I. Closed Networks at Low
  Load

abstract:
  We prove that the general mean-field type networks at low load behave in
accordance with the Poisson Hypothesis. That means that the network
equilibrates in time independent of its size. This is a "high-temperature"
counterpart of our earlier result, where we have shown that at high load the
relaxation time can diverge with the size of the network ("low-temperature").
In other words, the phase transitions in the networks can happen at high load,
but cannot take place at low load.


title:
Three-body Recombination of Lithium-6 Atoms with Large Negative
  Scattering Lengths

abstract:
  The 3-body recombination rate at threshold for distinguishable atoms with
large negative pair scattering lengths is calculated in the zero-range
approximation. The only parameters in this limit are the 3 scattering lengths
and the Efimov parameter, which can be complex valued. We provide semi-analytic
expressions for the cases of 2 or 3 equal scattering lengths and we obtain
numerical results for the general case of 3 different scattering lengths. Our
general result is applied to the three lowest hyperfine states of Lithium-6
atoms. Comparisons with recent experiments provide indications of loss features
associated with Efimov trimers near the 3-atom threshold.


title:
Entropy inference and the James-Stein estimator, with application to
  nonlinear gene association networks

abstract:
  We present a procedure for effective estimation of entropy and mutual
information from small-sample data, and apply it to the problem of inferring
high-dimensional gene association networks. Specifically, we develop a
James-Stein-type shrinkage estimator, resulting in a procedure that is highly
efficient statistically as well as computationally. Despite its simplicity, we
show that it outperforms eight other entropy estimation procedures across a
diverse range of sampling scenarios and data-generating models, even in cases
of severe undersampling. We illustrate the approach by analyzing E. coli gene
expression data and computing an entropy-based gene-association network from
gene expression data. A computer program is available that implements the
proposed shrinkage estimator.


title: Pseudo-parallel Lagrangian submanifolds are semi-parallel

abstract:
  We prove a conjecture formulated by Pablo M. Chacon and Guillermo A. Lobos in
[Pseudo-parallel Lagrangian submanifolds in complex space forms, Differential
Geom. Appl.] stating that every Lagrangian pseudo-parallel submanifold of a
complex space form of dimension at least 3 is semi-parallel.


title: Relaxation due to random collisions with a many-qudit environment

abstract:
  We analyze the dynamics of a system qudit of dimension mu sequentially
interacting with the nu-dimensional qudits of a chain playing the ore of an
environment. Each pairwise collision has been modeled as a random unitary
transformation. The relaxation to equilibrium of the purity of the system
qudit, averaged over random collisions, is analytically computed by means of a
Markov chain approach. In particular, we show that the steady state is the one
corresponding to the steady state for random collisions with a single
environment qudit of effective dimension nu_e=nu*mu. Finally, we numerically
investigate aspects of the entanglement dynamics for qubits (mu=nu=2) and show
that random unitary collisions can create multipartite entanglement between the
system qudit and the qudits of the chain.


title:
Detecting a Stochastic Gravitational-Wave Background: The Overlap
  Reduction Function

abstract:
  Detection of a gravitational-wave stochastic background via ground or
space-based gravitational-wave detectors requires the cross-correlation of the
response of two or more independent detectors. The cross-correlation involves a
frequency-dependent factor -- the so-called overlap reduction function or
Hellings-Downs curve -- that depends on the relative geometry of each detector
pair: i.e., the detector separations and the relative orientation of their
antenna patterns (beams). An incorrect formulation of this geometrical factor
has appeared in the literature, leading to incorrect conclusions regarding the
sensitivity of proposed detectors to a stochastic gravitational-wave
background. To rectify these errors and as a reference for future work we
provide here a complete, first-principles derivation of the overlap reduction
function and assess the nature of the errors associated with the use of the
incorrect expression that has appeared in the literature. We describe the
behavior of the overlap reduction function in different limiting regimes, and
show how the difference between the correct and incorrect expressions can be
understood physically.