title: A number filter for matter-waves

abstract:
  In current Bose-Einstein condensate experiments, the shot-to-shot variation
of atom number fluctuates up to 10%. In here, we present a procedure to
suppress such fluctuations by using a nonlinear p-pi-pbar matter wave
interferometer for a Bose-Einstein condensate with two internal states and a
high beam-splitter asymmetry (p, pbar not-equal 0.5). We analyze the situation
for an inhomogeneous trap within the Gross-Pitaevskii mean-field theory, as
well as a quantum mechanical Josephson model, which addresses complementary
aspects of the problem and agrees well otherwise.


title: Modified f(R) gravity unifying R^m inflation with \LambdaCDM epoch

abstract:
  We consider modified $f(R)$ gravity which may unify $R^m$ early-time
inflation with late-time $\Lambda$CDM epoch. It is shown that such model passes
the local tests (Newton law, stability of Earth-like gravitational solution,
very heavy mass for additional scalar degree of freedom) and suggests the
realistic alternative for General Relativity. Various scenarios for future
evolution of $f(R)$ $\Lambda$CDM era are discussed.


title: Lagrangian statistics in forced two-dimensional turbulence

abstract:
  We report on simulations of two-dimensional turbulence in the inverse energy
cascade regime. Focusing on the statistics of Lagrangian tracer particles,
scaling behavior of the probability density functions of velocity fluctuations
is investigated. The results are compared to the three-dimensional case. In
particular an analysis in terms of compensated cumulants reveals the transition
from a strong non-Gaussian behavior with large tails to Gaussianity. The
reported computation of correlation functions for the acceleration components
sheds light on the underlying dynamics of the tracer particles.


title:
A regularity and compactness theory for immersed stable minimal
  hypersurfaces of multiplicity at most 2

abstract:
  We prove that a stable minimal hypersurface of an open ball having a singular
set of locally finite codimension 2 Hausdorff measure which is weakly close to
a multiplicity 2 hyperplane is a 2-valued C^{1, alpha} graph in the interior.
Applications including a compactness theorem for a class of immersed stable
minimal hypersurfaces and a pointwise curvature estimate for the hypersurfaces
in this class in low dimensions are also discussed.


title: Semileptonic D-decays and Lattice QCD

abstract:
  We explore four different strategies to extract the D-meson semileptonic
decay form factors from the Green functions computed in QCD numerically on the
lattice. From our numerical tests we find that two such strategies, based on
the use of double ratios of 3-point correlation functions, lead to an
appreciable reduction of systematic uncertainties. This is an important step in
reducing the overall uncertainty in the lattice QCD results for the D-decay
form factors which are needed to determine the CKM entries |Vcd| and |Vcs|
experimentally, that are nowadays known by imposing the unitarity of the CKM
matrix.


title:
Neutrino Mass Matrix from Seesaw Mechanism with Heavy Majorana Neutrino
  Subject to Texture Zero and Invariant Under a Cyclic Permutation

abstract:
  We evaluate the predictive power of the neutrino mass matrices arising from
seesaw mechanism with heavy Majorana mass matrices subject to texture zero and
satisfy a cyclic permutation invariant form to the solar neutrino mixing
phenomena. From eight possible patterns of heavy Majorana neutrino mass matrix,
we found that there is no heavy Majorana neutrino mass matrix to be invariant
in form under a cyclic permutation. But, by imposing an additional assumption
that at least one of the 2x2 sub-matrices of heavy Majorana neutrino mass
matrix inverse having zero determinant, we found that only two of the eight
possible patterns for heavy Majorana neutrino mass matrices to be invariant
under a cyclic permutation. One of the two invariant heavy Majorana neutrino
mass matrices could produces neutrino mass matrix $M_{\nu}$ that can be used to
explain the neutrino mixing phenomena for both solar and atmospheric neutrinos
qualitatively.


title: Non-Statistical gamma Rays from Fragments

abstract:
  Polarization mechanism by Strutinsky-Denisov gives rise to the electric
dipole radiation from fragments. Its probability calculated within the LDM
turns out to be ~3.5x10-2 per fission. The radiation occurs during
thermolization of the post-rupture deformation energy of the fragments, but
before the neutron emission.


title: Quantum problem solving as simultaneous computation

abstract:
  I provide an alternative way of seeing quantum computation. First, I describe
an idealized classical problem solving machine that, thanks to a many body
interaction, reversibly and nondeterministically produces the solution of the
problem under the simultaneous influence of all the problem constraints. This
requires a perfectly accurate, rigid, and reversible relation between the
coordinates of the machine parts - the machine can be considered the many body
generalization of another perfect machine, the bounching ball model of
reversible computation. The mathematical description of the machine, as it is,
is applicable to quantum problem solving, an extension of the quantum
algorithms that comprises the physical representation of the problem-solution
interdependence. The perfect relation between the coordinates of the machine
parts is transferred to the populations of the reduced density operators of the
parts of the computer register. The solution of the problem is reversibly and
nondeterministically produced under the simultaneous influence of the state
before measurement and the quantum principle. At the light of the present
notion of simultaneous computation, the quantum speed up turns out to be
"precognition" of the solution, namely the reduction of the initial ignorance
of the solution due to backdating, to before running the algorithm, a
time-symmetric part of the state vector reduction on the solution; as such, it
is bounded by state vector reduction through an entropic inequality. PACS
numbers: 03.67.Lx, 01.55.+b, 01.70.+w


title:
The GBT350 Survey of the Northern Galactic Plane for Radio Pulsars and
  Transients

abstract:
  Using the Green Bank Telescope (GBT) and Pulsar Spigot at 350MHz, we have
surveyed the Northern Galactic Plane for pulsars and radio transients. This
survey covers roughly 1000 square degrees of sky within 75 deg < l < 165 deg
and |b| < 5.5 deg, a region of the Galactic Plane inaccessible to both the
Parkes and Arecibo multibeam surveys. The large gain of the GBT along with the
high time and frequency resolution provided by the Spigot make this survey more
sensitive by factors of about 4 to slow pulsars and more than 10 to millisecond
pulsars (MSPs), compared with previous surveys of this area. In a preliminary,
reduced-resolution search of all the survey data, we have discovered 33 new
pulsars, almost doubling the number of known pulsars in this part of the
Galaxy. While most of these sources were discovered by normal periodicity
searches, 5 of these sources were first identified through single, dispersed
bursts. We discuss the interesting properties of some of these new sources.
Data processing using the data's full-resolution is ongoing, with the goal of
uncovering MSPs missed by our first, coarse round of processing.


title: Field Theory on Nonanticommutative Superspace

abstract:
  We discuss a deformation of the Hopf algebra of supersymmetry (SUSY)
transformations based on a special choice of twist. As usual, algebra itself
remains unchanged, but the comultiplication changes. This leads to the deformed
Leibniz rule for SUSY transformations. Superfields are elements of the algebra
of functions of the usual supercoordinates. Elements of this algebra are
multiplied by using a $\star$-product which is noncommutative, hermitian and
finite when expanded in power series of the deformation parameter. Chiral
fields are no longer a subalgebra of the algebra of superfields. One possible
deformation of the Wess-Zumino action is proposed and analysed in detail.
Differently from most of the literature concerning this subject, we work in
Minkowski space-time.


title:
Manifold and metric in numerical solution of the quasi-static
  electromagnetic boundary value problems

abstract:
  Classical vector analysis is the predominant formalism used by engineers of
computational electromagnetism, despite the fact that manifold as a theoretical
concept has existed for a century. This paper discusses the benefits of
manifolds over the traditional approach in practical problems of modelling.
With a structural approach, it outlines the role and interdependence of
coordinate systems, metric, constitutive equations, and fields, and relates
them to practical problems of quasi-static computational electromagnetics: mesh
generation, open-boundary problems, and electromagnetic-mechanical coupled
problems involving motion and deformation. The proposed procedures also imply
improvements to the flexibility of the modelling software.


title: One-loop corrections to three-body leptonic chargino decays

abstract:
  We calculate full one-loop corrections to the genuine three-body decays of
the light chargino \chi_1^\pm to \chi^0_1 l^\pm \nu in the Minimal
Supersymmetric Standard Model. We find that the corrections to the decay width
can be of the order of a few percent. We show also how radiative corrections
affect energy and angular distributions of the final lepton.


title: On the frequency and temperature dependence of the conductivity

abstract:
  We obtain the frequency and temperature dependence of the conductivity for
(disordered) solids, where the temperature dependence is defined in terms of
the related thermodynamic state function in exponential (or power law, etc.)
forms. The model is applied to n-type Si with various donor and acceptor
impurities and several concentrations at T about 0 Kelvin and sodium borate
glasses and mixed alkalis with various compositions (x) in all at T about 500
Kelvin. The results are found in good agreement with experiments.


title:
3000 % high-field magnetoresistance in super-lattices of CoFe
  nanoparticles

abstract:
  We report on magnetotransport measurements on millimetre-large super-lattices
of CoFe nanoparticles surrounded by an organic layer. Electrical properties are
typical of Coulomb blockade in three dimensional arrays of nanoparticles. A
large high-field magnetoresistance, reaching up to 3000 %, is measured between
1.8 and 10 K. This exceeds by two orders of magnitude magnetoresistance values
generally measured in arrays of 3d metals ferromagnetic nanoparticles. The
magnetoresistance amplitude scales with the magnetic field / temperature ratio
and displays an unusual exponential dependency with the applied voltage. The
magnetoresistance abruptly disappears below 1.8 K. We propose that the
magnetoresistance is due to some individual paramagnetic moments localized
between the metallic core of the nanoparticles, the origin of which is
discussed.


title: Effective string theory description of the interface free energy

abstract:
  We compare the predictions of the Nambu-Goto effective string model with a
set of high precision Monte Carlo results for interfaces with periodic boundary
conditions in the 3D Ising model. We compute the free energy in the covariant
gauge exactly, up to the inclusion of the Liouville mode. The perturbative
expansion of this result agrees both with the result evaluated several years
ago by Dietz and Filk in the physical gauge and with a recent calculation with
the Polchinski-Strominger action. We also derive the effective string spectrum
which, because of the different boundary conditions, is very different from the
well known one of Arvis. Taking into proper account the effective string
corrections and exploiting some technical improvements in the simulations we
obtain precise estimate of the amplitude ratios T_c/\sqrt{sigma},
m_{0++}/\sqrt{\sigma} and sigma xi_{2nd}^2. We also discuss the behaviour of
the effective string free energy in the dimensional reduction limit (i.e., near
the deconfinement transition of the dual 3d gauge Ising model) and its
relationship with the 2d Ising model interfaces


title:
The formation and evolution of very massive stars in dense stellar
  systems

abstract:
  The early evolution of dense stellar systems is governed by massive single
star and binary evolution. Core collapse of dense massive star clusters can
lead to the formation of very massive objects through stellar collisions
($M\geq$ 1000 \msun). Stellar wind mass loss determines the evolution and final
fate of these objects, and decides upon whether they form black holes (with
stellar or intermediate mass) or explode as pair instability supernovae,
leaving no remnant. We present a computationaly inexpensive evolutionary scheme
for very massive stars that can readily be implemented in an N-body code. Using
our new N-body code 'Youngbody' which includes a detailed treatment of massive
stars as well as this new scheme for very massive stars, we discuss the
formation of intermediate mass and stellar mass black holes in young starburst
regions. A more detailed account of these results can be found in Belkus et al.
2007.


title: A generalisation of the Cauchy-Kovalevskaia theorem

abstract:
  I prove, under mild assumptions, that solutions to linear evolution equations
admit sectorial solutions. The size of the sector depends on the regularity of
the initial data. If it is regular enough the solution is holomorphic and
unique otherwise it is sectorial. I also prove that the result is optimal for
many partial differential systems (which includes KdV and other examples).


title:
Strong reduction of field-dependent microwave surface resistance in
  YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ with sub-micrometric BaZrO$_3$ inclusions

abstract:
  We observe a strong reduction of the field induced thin film surface
resistance measured at high microwave frequency ($\nu=$47.7 GHz) in
YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ thin films grown on SrTiO$_3$ substrates, as a
consequence of the introduction of sub-micrometric BaZrO$_3$ particles. The
field increase of the surface resistance is smaller by a factor of $\sim$3 in
the film with BaZrO$_3$ inclusions, while the zero-field properties are not
much affected. Combining surface resistance and surface reactance data we
conclude (a) that BaZrO$_3$ inclusions determine very deep and steep pinning
wells and (b) that the pinning changes nature with respect to the pure film.


title: Kaon Pair Production in Proton--Proton Collisions

abstract:
  The differential and total cross sections for kaon pair production in the
pp->ppK+K- reaction have been measured at three beam energies of 2.65, 2.70,
and 2.83 GeV using the ANKE magnetic spectrometer at the COSY-Juelich
accelerator. These near-threshold data are separated into pairs arising from
the decay of the phi-meson and the remainder. For the non-phi selection, the
ratio of the differential cross sections in terms of the K-p and K+p invariant
masses is strongly peaked towards low masses. This effect can be described
quantitatively by using a simple ansatz for the K-p final state interaction,
where it is seen that the data are sensitive to the magnitude of an effective
K-p scattering length. When allowance is made for a small number of phi events
where the K- rescatters from the proton, the phi region is equally well
described at all three energies. A very similar phenomenon is discovered in the
ratio of the cross sections as functions of the K-pp and K+pp invariant masses
and the identical final state interaction model is also very successful here.
The world data on the energy dependence of the non-phi total cross section is
also reproduced, except possibly for the results closest to threshold.


title: Photon Correlation Spectroscopy for Observing Natural Lasers

abstract:
  Natural laser emission may be produced whenever suitable atomic energy levels
become overpopulated. Strong evidence for laser emission exists in astronomical
sources such as Eta Carinae, and other luminous stars. However, the evidence is
indirect in that the laser lines have not yet been spectrally resolved. The
lines are theoretically estimated to be extremely narrow, requiring spectral
resolutions very much higher (R approx.= 10**8) than possible with ordinary
spectroscopy. Such can be attained with photon-correlation spectroscopy on
nanosecond timescales, measuring the autocorrelation function of photon arrival
times to obtain the coherence time of light, and thus the spectral linewidth. A
particular advantage is the insensitivity to spectral, spatial, and temporal
shifts of emission-line components due to local velocities and probable
variability of 'hot-spots' in the source. A laboratory experiment has been set
up, simulating telescopic observations of cosmic laser emission. Numerically
simulated observations estimate how laser emission components within realistic
spectral and spatial passbands for various candidate sources carry over to
observable statistical functions.


title:
Adsorption of H2O, NH3, CO, NO2, and NO on graphene: A first-principles
  study

abstract:
  Motivated by the recent realization of graphene sensors to detect individual
gas molecules, we investigate the adsorption of H2O, NH3, CO, NO2, and NO on a
graphene substrate using first-principles calculations. The optimal adsorption
position and orientation of these molecules on the graphene surface is
determined and the adsorption energies are calculated. Molecular doping, i.e.
charge transfer between the molecules and the graphene surface, is discussed in
light of the density of states and the molecular orbitals of the adsorbates.
The efficiency of doping of the different molecules is determined and the
influence of their magnetic moment is discussed.


title:
Unconventional particle-hole mixing in the systems with strong
  superconducting fluctuations

abstract:
  Development of the STM and ARPES spectroscopies enabled to reach the
resolution level sufficient for detecting the particle-hole entanglement in
superconducting materials. On a quantitative level one can characterize such
entanglement in terms of the, so called, Bogoliubov angle which determines to
what extent the particles and holes constitute the spatially or momentum
resolved excitation spectra. In classical superconductors, where the phase
transition is related to formation of the Cooper pairs almost simultaneously
accompanied by onset of their long-range phase coherence, the Bogoliubov angle
is slanted all the way up to the critical temperature Tc. In the high
temperature superconductors and in superfluid ultracold fermion atoms near the
Feshbach resonance the situation is different because of the preformed pairs
which exist above Tc albeit loosing coherence due to the strong quantum
fluctuations. We discuss a generic temperature dependence of the Bogoliubov
angle in such pseudogap state indicating a novel, non-BCS behavior. For
quantitative analysis we use a two-component model describing the pairs
coexisting with single fermions and study their mutual feedback effects by the
selfconsistent procedure originating from the renormalization group approach.


title: Neutralino Dark Matter in SUSY-SU(5) with RH neutrinos

abstract:
  In the context of low-energy Supersymmetry, a model of Grand Unification with
right-handed neutrinos, based on the group SU(5), is discussed and its
implications for neutralino dark matter (DM) are studied and compared with the
constrained MSSM. RG effects in this model modify the sparticle spectrum such
that the WMAP limit on the DM relic density cannot be satisfied for small
values of $\tan\beta$ ($\tan\beta \lesssim 35$) and the region of the parameter
space allowed by efficient neutralino-stau coannihilation presents a peculiar
phenomenology and an upper bound on the neutralino mass for most of the
parameters choices.


title: A Spectral Analysis Approach for Gaussian Mixture Estimation

abstract:
  This paper deals with the estimation of one-dimensional Gaussian mixture.
Given a set of observations of a K-component Gaussian mixture, we focus on the
estimation of the component expectations. The number of components is supposed
to be known. Our method is based on a spectral analysis of the estimated first
characteristic function. We construct a Toeplitz matrix RM with 2M-1 estimated
samples of the first characteristic function and show that the mixture
component expectations can be derived from the eigenvector decomposition of RM.
Simulations illustrate the performance of our algorithm on several
configurations of a six-component Gaussian mixture. In the investigated
scenarios the proposed method outperforms the Expectation-Maximization
algorithm


title: Search for Charged Higgs Bosons at the LHC

abstract:
  The discovery potential for charged Higgs bosons at the ATLAS and CMS
experiments is discussed with focus on the MSSM. Studies for several decay
channels for the charged Higgs boson are presented both for production in top
quark decays and gluon-gluon/gluon-bottom fusion.


title:
Static potential for the quark-antiquark-gluon hybrid system in lattice
  QCD

abstract:
  The static gluon-quark-antiquark interaction is investigated using lattice
QCD techniques. A Wilson loop adequate to the static hybrid three-body system
is developed and, using a $24^3 \times 48$ periodic lattice with $\beta = 6.2$,
the potential energy of the system is measured for different geometries. For
the medium range behaviour, when the quarks are far apart, we find a string
tension which is compatible with two fundamental strings. On the other hand,
when the quark and antiquark are nearby, the string tension is larger than two
fundamental strings and is compatible with the Casimir scaling.


title: Linearized Torsion Waves in a Tensor-Tensor Theory of Gravity

abstract:
  We investigate a linearized tensor-tensor theory of gravity with torsion and
a perturbed torsion wave solution is discovered in background Minkowski
spacetime with zero torsion. Furthermore, gauge transformations of any
perturbed tensor field are derived in general background non-Riemannian
geometries. By calculating autoparallel deviations, both longitudinal and
transverse polarizations of the torsion wave are discovered.


title:
The weighed average geodetic of distributions of probabilities in the
  statistical physics

abstract:
  The results received in works [Centsov N.N. [N.N. Chentsov], Statistical
decision rules and optimal inference, 1982 Amer. Math. Soc. (Translated from
Russian); Morozova, E. A., Chentsov, N. N. Natural geometry of families of
probability laws. 1991 Probability theory, 8, 133--265, 270--274, 276 (in
Russian)] for statistical distributions at studying algebra of decision rules
and natural geometry generated by her, are applied to estimations of the
nonequilibrium statistical operator and superstatistics. Expressions for the
nonequilibrium statistical operator and superstatistics are received as special
cases of the weighed average geodetic of distributions of probabilities.


title: NMR Time Reversal as a Probe of Incipient Turbulent Spin Dynamics

abstract:
  We demonstrate time reversal of nuclear spin dynamics in highly magnetized
dilute liquid 3He-4He mixtures through effective inversion of long-range
dipolar interactions. These experiments, which involve using magic sandwich NMR
pulse sequences to generate spin echoes, probe the spatiotemporal development
of turbulent spin dynamics and promise to serve as a versatile tool for the
study and control of dynamic magnetization instabilities. We also show that a
repeated magic sandwich pulse sequence can be used to dynamically stabilize
modes of nuclear precession that are otherwise intrinsically unstable. To date,
we have extended the effective precession lifetimes of our magnetized samples
by more than three orders of magnitude.


title:
NMR Time Reversal Experiments in Highly Polarised Liquid 3He-4He
  Mixtures

abstract:
  Long-range magnetic interactions in highly magnetised liquids
(laser-polarised 3He-4He dilute mixtures at 1 K in our experiment) introduce a
significant non-linear and non-local contribution to the evolution of nuclear
magnetisation that leads to instabilities during free precession. We recently
demonstrated that a multi-echo NMR sequence, based on the magic sandwich pulse
scheme developed for solid-state NMR, can be used to stabilise the
magnetisation against the effect of distant dipolar fields. Here, we report
investigations of echo attenuation in an applied field gradient that show the
potential of this NMR sequence for spin diffusion measurements at high
magnetisation densities.


title:
Primary particle acceleration above 100 TeV in the shell-type Supernova
  Remnant RX J1713.7--3946 with deep H.E.S.S. observations

abstract:
  The shell-type supernova remnant RX J1713.7--3946 was observed during three
years with the H.E.S.S. Cherenkov telescope system. The first observation
campaign in 2003 yielded the first-ever resolved TeV gamma-ray image. Follow-up
observations in 2004 and 2005 revealed the very-high-energy gamma-ray
morphology with unprecedented precision and enabled spatially resolved spectral
studies. Combining the data of three years, we obtain significantly increased
statistics and energy coverage of the gamma-ray spectrum as compared to earlier
H.E.S.S. results. We present the analysis of the data of different years
separately for comparison and demonstrate that the telescope system operates
stably over the course of three years. When combining the data sets, a
gamma-ray image is obtained with a superb angular resolution of 0.06 degrees.
The combined spectrum extends over three orders of magnitude, with significant
gamma-ray emission approaching 100 TeV. For realistic scenarios of
very-high-energy gamma-ray production, the measured gamma-ray energies imply
efficient particle acceleration of primary particles, electrons or protons, to
energies exceeding 100 TeV in the shell of RX J1713.7--3946.


title: Phase Transitions in the Pseudospin-Electron Model

abstract:
  A review of the present state of investigations of the pseudospin-electron
model (PEM), which is used in the theory of strongly correlated electron
systems, is given. The model is used to describe the systems with the locally
anharmonic elements of structure represented in the model by pseudospins. The
consideration is based on the dynamical mean field theory approach and the
generalized random phase approximation. Electron spectrum and thermodynamics of
the model are investigated; the cases of the simplified model, the model with
strong interaction and the two-sublattice model are studied more in detail. The
phase transitions into other uniform or modulated states as well as
superconducting phases are described; the criteria of their realization are
established. Based on this, the description of structural and dielectric
(ferroelectric type) instabilities, phase separation and bistability phenomena
is given. A comparison is made with the thermodynamics of the Falicov-Kimball
model (which can be considered as a particular case of PEM). The possibility of
applying the PEM to the analysis of thermodynamics of the real HTSC systems is
discussed. Attention is paid to the unsolved problems in the study of PEM.


title:
Critical Oxide Thickness for Efficient Single-walled Carbon Nanotube
  Growth on Silicon Using Thin SiO2 Diffusion Barriers

abstract:
  The ability to integrate carbon nanotubes, especially single-walled carbon
nanotubes, seamlessly onto silicon would expand the range of applications
considerably. Though direct integration using chemical vapor deposition is the
simplest method, the growth of single-walled carbon nanotubes on bare silicon
and on ultra-thin oxides is greatly inhibited due to the formation of a
non-catalytic silicide. Using x-ray photoelectron spectroscopy, we show that
silicide formation occurs on ultra-thin oxides due to thermally activated metal
diffusion through the oxide. Silicides affect the growth of single-walled
nanotubes more than multi-walled nanotubes due to the increased kinetics at the
higher single-walled nanotube growth temperature. We demonstrate that nickel
and iron catalysts, when deposited on clean silicon or ultra-thin silicon
dioxide layers, begin to form silicides at relatively low temperatures, and
that by 900C, all of the catalyst has been incorporated into the silicide,
rendering it inactive for subsequent single-walled nanotube growth. We further
show that a 4 nm silicon dioxide layer is the minimum diffusion barrier
thickness which allows for efficient single-walled nanotube growth.


title:
Effelsberg Observations of Excited-State (6.0 GHz) OH in Supernova
  Remnants and W3(OH)

abstract:
  While masers in the 1720 MHz transition of OH are detected toward many
supernova remnants (SNRs), no other OH transition is seen as a maser in SNRs.
We present a search for masers at 6049 MHz, which has recently been predicted
to produce masers by pure collisional excitation at conditions similar to that
required for 1720 MHz masing. The Effelsberg 100 m telescope was used to
observe the excited-state 6016, 6030, 6035, and 6049 MHz lines of OH toward
selected SNRs, most of which have previously-detected bright 1720 MHz masers.
No excited-state masers are found toward SNRs, consistent with previous
observations of the 6049 MHz and other excited-state transitions. We do not see
clear evidence of absorption toward SNR target positions, although we do see
evidence of absorption in the molecular cloud at +50 km/s near Sgr A East. Weak
absorption is detected at 6016 MHz toward W3(OH), while stronger, narrower
emission is seen at 6049 MHz, suggesting that the 6049 MHz emission is a
low-gain maser. We conclude that conditions in SNRs are not conducive to
excited-state maser emission, especially in excited-state satellite lines.


title: Crystallization and melting of bacteria colonies and Brownian Bugs

abstract:
  Motivated by the existence of remarkably ordered cluster arrays of bacteria
colonies growing in Petri dishes and related problems, we study the spontaneous
emergence of clustering and patterns in a simple nonequilibrium system: the
individual-based interacting Brownian bug model. We map this discrete model
into a continuous Langevin equation which is the starting point for our
extensive numerical analyses. For the two-dimensional case we report on the
spontaneous generation of localized clusters of activity as well as a
melting/freezing transition from a disordered or isotropic phase to an ordered
one characterized by hexagonal patterns. We study in detail the analogies and
differences with the well-established Kosterlitz-Thouless-Halperin-Nelson-Young
theory of equilibrium melting, as well as with another competing theory. For
that, we study translational and orientational correlations and perform a
careful defect analysis. We find a non standard one-stage, defect-mediated,
transition whose nature is only partially elucidated.


title:
Cross-Participants : fostering design-use mediation in an Open Source
  Software community

abstract:
  Motivation - This research aims at investigating emerging roles and forms of
participation fostering design-use mediation during the Open Source Software
design process Research approach - We compare online interactions for a
successful "pushed-by-users" design process with unsuccessful previous
proposals. The methodology developed, articulate structural analyses of the
discussions (organization of discussions, participation) to actions to the code
and documentation made by participants to the project. We focus on the
useroriented and the developer-oriented mailing-lists of the Python project.
Findings/Design - We find that key-participants, the cross-participants, foster
the design process and act as boundary spanners between the users and the
developers' communities. Research limitations/Implications - These findings can
be reinforced developing software to automate the structural analysis of
discussions and actions to the code and documentation. Further analyses,
supported by these tools, will be necessary to generalise our results.
Originality/Value - The analysis of participation among the three interaction
spaces of OSS design (discussion, documentation and implementation) is the main
originality of this work compared to other OSS research that mainly analyse one
or two spaces. Take away message - Beside the idealistic picture that users may
intervene freely in the process, OSS design is boost and framed by some
key-participants and specific rules and there can be barriers to users'
participation


title: Meridional Circulation and Global Solar Oscillations

abstract:
  We investigate the influence of large-scale meridional circulation on solar
p-modes by quasi-degenerate perturbation theory, as proposed by
\cite{lavely92}. As an input flow we use various models of stationary
meridional circulation obeying the continuity equation. This flow perturbs the
eigenmodes of an equilibrium model of the Sun. We derive the signatures of the
meridional circulation in the frequency multiplets of solar p-modes. In most
cases the meridional circulation leads to negative average frequency shifts of
the multiplets. Further possible observable effects are briefly discussed.


title:
Morin singularities and global geometry in a class of ordinary
  differential operators

abstract:
  We consider the operator $F(u) = u' + f(t,u(t))$ acting on periodic real
valued functions. Generically, critical points of $F$ are infinite dimensional
Morin-like singularities and we provide operational characterizations of the
singularities of different orders. A global Lyapunov-Schmidt decomposition of
$F$ converts $F$ into adapted coordinates, $\Fbd(\tilde v, \overline u) =
(\tilde v, \overline v)$, where $\tilde v$ is a function of average zero and
both $\overline u$ and $\overline v$ are numbers. Thus, global geometric
aspects of $F$ reduce to the study of a family of one-dimensional maps: we use
this approach to obtain normal forms for several nonlinearities $f$. For
example, we characterize autonomous nonlinearities giving rise to global folds
and, in general, we show that $F$ is a global fold if all critical points are
folds. Also, $f(t,x) = x^3 - x$, or, more generally, the Cafagna-Donati
nonlinearity, yield global cusps; for $F$ interpreted as a map between
appropriate Hilbert spaces, the requested changes of variable to bring $F$ to
normal form can be taken to be diffeomorphisms. A key ingredient in the
argument is the contractibility of both the critical set and the set of
non-folds for a generic autonomous nonlinearity. We also obtain a numerical
example of a polynomial $f$ of degree 4 for which $F$ contains butterflies
(Morin singularities of order 4)---% it then follows that $F(u) = v$ has six
solutions for some $v$.


title: Quantum Entanglement in Some Physical Systems

abstract:
  The summary of the Author's results on Bell inequalities and macroscopic
entanglement.


title: Refined Topological Vertex and Instanton Counting

abstract:
  It has been proposed recently that topological A-model string amplitudes for
toric Calabi-Yau 3-folds in non self-dual graviphoton background can be
caluculated by a diagrammatic method that is called the ``refined topological
vertex''. We compute the extended A-model amplitudes for SU(N)-geometries using
the proposed vertex. If the refined topological vertex is valid, these
computations should give rise to the Nekrasov's partition functions of N=2
SU(N) gauge theories via the geometric engineering. In this article, we verify
the proposal by confirming the equivalence between the refined A-model
amplitude and the K-theoretic version of the Nekrasov's partition function by
explicit computation.


title: Magnetism, rotation and accretion in Herbig Ae-Be stars

abstract:
  Studies of stellar magnetism at the pre-main sequence phase can provide
important new insights into the detailed physics of the late stages of star
formation, and into the observed properties of main sequence stars. This is
especially true at intermediate stellar masses, where magnetic fields are
strong and globally organised, and therefore most amenable to direct study.
This talk reviews recent high-precision ESPaDOnS observations of pre-main
sequence Herbig Ae-Be stars, which are yielding qualitatively new information
about intermediate-mass stars: the origin and evolution of their magnetic
fields, the role of magnetic fields in generating their spectroscopic activity
and in mediating accretion in their late formative stages, and the factors
influencing their rotational angular momentum.


title:
Sizes of Confirmed Globular Clusters in NGC 5128: A Wide-Field
  High-Resolution Study

abstract:
  Using Magellan/IMACS images covering a 1.2 x 1.2 sq. degree FOV with seeing
of 0.4"-0.6", we have applied convolution techniques to analyse the light
distribution of 364 confirmed globular cluster in the field of NGC 5128 and to
obtain their structural parameters. Combining these parameters with existing
Washington photometry from Harris et al. (2004), we are able to examine the
size difference between metal-poor (blue) and metal-rich (red) globular
clusters. For the first time, this can be addressed on a sample of confirmed
clusters that extends to galactocentric distances about 8 times the effective
radius, R$_{eff}$, of the galaxy. Within 1 R$_{eff}$, red clusters are about
30% smaller on average than blue clusters, in agreement with the vast majority
of extragalactic globular cluster systems studied. As the galactocentric
distance increases, however, this difference becomes negligible. Thus, our
results indicate that the difference in the clusters' effective radii, r$_e$,
could be explained purely by projection effects, with red clusters being more
centrally concentrated than blue ones and an intrinsic r$_e$--R$_{gc}$
dependence, like the one observed for the Galaxy.


title: Polymer drift in a solvent by force acting on one polymer end

abstract:
  We investigate the effect of hydrodynamic interactions on the non-equilibrium
drift dynamics of an ideal flexible polymer pulled by a constant force applied
at one end of the polymer using the perturbation theory and the renormalization
group method. For moderate force, if the polymer elongation is small, the
hydrodynamic interactions are not screened and the velocity and the
longitudinal elongation of the polymer are computed using the renormalization
group method. Both the velocity and elongation are nonlinear functions of the
driving force in this regime. For large elongation we found two regimes. For
large force but finite chain length $L$ the hydrodynamic interactions are
screened. For large chain lengths and a finite force the hydrodynamic
interactions are only partially screened, which in three dimensions results in
unusual logarithmic corrections to the velocity and the longitudinal
elongation.


title: Magnetism and rotation in Herbig Ae/Be stars

abstract:
  Among the main sequence intermediate mass A and B stars, around 5% host
large-scale organized magnetic fields. Most of these stars are very slow
rotators compared to their non-magnetic counterparts, and show photospheric
abundance anomalies. They are referred to as the Ap/Bp stars. One of the
greatest challenges, today is to understand the origin of their magnetic field
and their slow rotation. The favoured hypothesis is a fossil origin of the
magnetic field, in which the magnetic fields of Ap/Bp stars are relics of those
which existed in the parental molecular clouds during the formation. This
implies that the magnetic field must survive all the initial phases of the
stellar evolution and especially the pre-main sequence (PMS) phase. This is
consistent with the general belief that magnetic braking occurs during the PMS
phase, which sheds angular momentum and slows the rotation of these stars. In
this context, we proceeded with a survey of a sample of around 50 PMS Herbig
Ae/Be stars, using the new spectropolarimeter ESPaDOnS at the CFHT, in order to
study the magnetic field and the rotation velocity of these stars. This talk
reviews the results of our survey, as well as their consequences for the origin
of the magnetic fields and the evolution of the rotation of intermediate mass
stars during the PMS phase.


title:
A near-ultraviolet view of the Inner Region of M31 with the Large
  Binocular Telescope

abstract:
  We present a 900 sec, wide-field U image of the inner region of the Andromeda
galaxy obtained during the commissioning of the blue channel of the Large
Binocular Camera mounted on the prime focus of the Large Binocular Telescope.
Relative photometry and absolute astrometry of individual sources in the image
was obtained along with morphological parameters aimed at discriminating
between stars and extended sources, e.g. globular clusters. The image unveils
the near-ultraviolet view of the inner ring of star formation recently
discovered in the infrared by the Spitzer Space Telescope and shows in great
detail the fine structure of the dust lanes associated with the galaxy inner
spiral arms. The capabilities of the blue channel of the Large Binocular Camera
at the Large Binocular Telescope (LBC-Blue) are probed by direct comparison
with ultraviolet GALEX observations of the same region in M31. We discovered 6
new candidate stellar clusters in this high-background region of M31. We also
recovered 62 bona-fide globulars and 62 previously known candidates from the
Revised Bologna Catalogue of the M31 globular clusters, and firmly established
the extended nature of 19 of them.


title: Linear and nonlinear tails I: general results and perturbation theory

abstract:
  For nonlinear wave equations with a potential term we prove pointwise
space-time decay estimates and develop a perturbation theory for small initial
data. We show that the perturbation series has a positive convergence radius by
a method which reduces the wave equation to an algebraic one. We demonstrate
that already first and second perturbation orders, satisfying linear equations,
can provide precise information about the decay of the full solution to the
nonlinear wave equation. In a forthcoming publication (part II) we address the
issue of optimal decay estimates and precise asymptotics under spherical
symmetry where the perturbation equations can be solved almost exactly.


title: Towards the Construction of Local Logarithmic Conformal Field Theories

abstract:
  Although logarithmic conformal field theories (LCFTs) are known not to
factorise many previous findings have only been formulated on their chiral
halves. Making only mild and rather general assumptions on the structure of an
chiral LCFT we deduce statements about its local non-chiral equivalent. Two
methods are presented how to construct local representations as
subrepresentations of the tensor product of chiral and anti-chiral Jordan
cells. Furthermore we explore the assembly of generic non-chiral correlation
functions from generic chiral and anti-chiral correlators. The constraint of
locality is studied and the generality of our method is discussed.


title: Designing a commutative replicated data type

abstract:
  Commuting operations greatly simplify consistency in distributed systems.
This paper focuses on designing for commutativity, a topic neglected
previously. We show that the replicas of \emph{any} data type for which
concurrent operations commute converges to a correct value, under some simple
and standard assumptions. We also show that such a data type supports
transactions with very low cost. We identify a number of approaches and
techniques to ensure commutativity. We re-use some existing ideas
(non-destructive updates coupled with invariant identification), but propose a
much more efficient implementation. Furthermore, we propose a new technique,
background consensus. We illustrate these ideas with a shared edit buffer data
type.


title: Dynamical overlap fermions with increased topological tunnelling

abstract:
  We present two improvements to our previous dynamical overlap HMC algorithm.
We introduce a new method of differentiating the eigenvectors of the Kernel
operator, which removes an instability in the fermionic force. Secondly, by
simulating part of the fermion determinant exactly, without pseudo-fermions, we
are able to increase the rate of topological tunnelling by a factor of more
than ten, reducing the auto-correlation.


title: Photometric study of the IC 65 group of galaxies

abstract:
  We carry out a photometric study of a poor group of late-type galaxies around
IC 65, with the aim: (a) to search for new dwarf members and to measure their
photometric characteristics; (b) to search for possible effects of mutual
interactions on the morphology and star-formation characteristics of luminous
and faint group members; (c) to evaluate the evolutionary status of this
particular group. We make use of our BRI CCD observations, DPOSS blue and red
frames, and the 2MASS JHK frames. In addition, we use the HI imaging data, the
far-infrared and radio data from the literature. Search for dwarf galaxies is
made using the SExtractor software. Detailed surface photometry is performed
with the MIDAS package. Four LSB galaxies were classified as probable dwarf
members of the group and the BRI physical and model parameters were derived for
the first time for all true and probable group members. Newly found dIrr
galaxies around the IC 65 contain a number of H II regions, which show a range
of ages and propagating star-formation. Mildly disturbed gaseous and/or stellar
morphology is found in several group members. Various structural, dynamical,
and star-forming characteristics let us conclude that the IC 65 group is a
typical poor assembly of late-type galaxies at an early stage of its dynamical
evolution with some evidence of intragroup (tidal) interactions.


title:
Large contribution of virtual Delbrueck scattering to the emission of
  photons by relativistic nuclei in nucleus-nucleus and electron-nucleus
  collisions

abstract:
  Delbrueck scattering is an elastic scattering of a photon in the Coulomb
field of a nucleus via a virtual electron loop. The contribution of this
virtual subprocess to the emission of a photon in the collision of
ultra-relativistic nuclei Z_1 Z_2 -> Z_1 Z_2 gamma is considered. We identify
the incoming virtual photon as being generated by one of the relativistic
nuclei involved in the binary collision and the scattered photon as being
emitted in the process. The energy and angular distributions of the photons are
calculated. The discussed process has no infrared divergence. The total cross
section obtained is 14 barn for Au-Au collisions at the RHIC collider and 50
barn for Pb-Pb collisions at the LHC collider. These cross sections are
considerably larger than those for ordinary tree-level nuclear bremsstrahlung
in the considered photon energy range m_e << E_\gamma << m_e gamma, where gamma
is the Lorentz factor of the nucleus. Finally, photon emission in
electron-nucleus collisions e Z -> e Z gamma is discussed in the context of the
eRHIC option.


title:
A Strong Upper Limit on the Pulsed Radio Luminosity of the Compact
  Object 1RXS J141256.0+792204

abstract:
  The ROSAT X-ray source 1RXS J141256.0+792204 has recently been identified as
a likely compact object whose properties suggest it could be a very nearby
radio millisecond pulsar at d = 80 - 260pc. We investigated this hypothesis by
searching for radio pulsations using the Westerbork Synthesis Radio Telescope.
We observed 1RXS J141256.0+792204 at 385 and 1380MHz, recording at high time
and frequency resolution in order to maintain sensitivity to millisecond
pulsations. These data were searched both for dispersed single pulses and using
Fourier techniques sensitive to constant and orbitally modulated periodicities.
No radio pulsations were detected in these observations, resulting in pulsed
radio luminosity limits of L_400 ~ 0.3 (d/250pc)^2 mJy kpc^2 and L_1400 ~ 0.03
(d/250pc)^2 mJy kpc^2 at 400 and 1400MHz respectively. The lack of detectable
radio pulsations from 1RXS J141256.0+792204 brings into question its
identification as a nearby radio pulsar, though, because the pulsar could be
beamed away from us, this hypothesis cannot be strictly ruled out.


title: Lifetime Difference and CP Asymmetry in the Bs -> J/psi phi decay

abstract:
  The Bs meson is an interesting particle to study because a sizable mixing
induced CP violation in the Bs-Bsbar system would be an indication for physics
beyond the Standard Model. In this paper we present a measurement of the
lifetime difference DeltaGamma between the Bs mass eigenstates and the CP
violating phase in the decay Bs -> J/psi phi. In 1.7 fb^-1 of data collected
with the CDF II detector at the Tevatron ppbar collider we measure DeltaGamma =
0.076 +0.059-0.063 (stat.) +- 0.006 (syst.) ps^-1, well consistent with the
Standard Model prediction, and a mean Bs lifetime of ctau_s = 456 +-13 (stat.)
+- 7 (syst.) m^-6. We find no evidence for CP violation.


title:
Static and dynamic properties of hadronic systems with heavy quarks b
  and c

abstract:
  This thesis has been devoted to the study of different properties of hadrons
with one and two heavy quarks $c$ and/or $b$. All calculations have been done
in the framework of a nonrelativistic constituent quark model. In order to
check the sensitivity of our results to the inter--quark interaction we have
used five different quark--quark potentials. The spread in results gives an
estimation of theoretical uncertainties and so has been quoted.
  Most observables studied change only at the level of a few per cent when
changing the interaction potential.
  Another source of theoretical uncertainty is the use of nonrelativistic
kinematics in the evaluation of the orbital wave functions and the construction
of our nonrelativistic states, although we think that a good part of these
relativistic effects are contained in an effective way in the parameters of the
quark-quark potentials, which were adjusted in the original works to reproduce
the experimental spectra of mesons. Mesons wave functions have been evaluated
using a Numerov algorithm, while for baryons the three body problem has been
solved using a variational approach with ansatz wave functions that include
simplifications that arise from HQS and HQSS. To compute hadron decays we have
relied on the impulse approximation, which induces small axial and vector
current conservation violations due to binding effects. These binding effects,
though they affect some of the weak form factors analyzed, have little
influence on the decay widths.


title: On duality of Drell-Yan and J/psi production processes

abstract:
  It is studied the model on J/psi production allowing to extract parton
distribution functions (PDFs) from the combined analysis with both data on
Drell-Yan and J/psi production processes. It is shown that this, so attractive
from theoretical point of view, model, can be safely used in the low energy
region E<100 GeV. The significance of gluon contributions to the J/psi
cross-sections is investigated. The obtained results in the high energy region
occur to be rather surprising.


title:
Inclusive production of $J/\psi$ meson in proton-proton collisions at
  BNL RHIC

abstract:
  Inclusive cross sections for $J/\psi$ production in proton-proton collisions
were calculated in the $k_t$-factorization approach for the RHIC energy.
Several mechanisms were considered, including direct color-singlet mechanism,
radiative decays of $\chi_c$ mesons, decays of $\psi'$, open-charm associated
production of $J/\psi$ as well as weak decays of B mesons. Different
unintegrated gluon distributions from the literature were used. We find that
radiative $\chi_c$ decays and direct color-singlet contributions constitute the
dominant mechanism of $J/\psi$ production. These process cannot be consistently
treated within collinear-factorization approach. The results are compared with
recent RHIC data. The new precise data at small transverse momenta impose
stringent constraints on UGDFs. Some UGDFs are inconsistent with the new data.
The Kwieci\'nski UGDFs give the best description of the data. In order to
verify the mechanism suggested here we propose $J/\psi$ -- jet correlation
measurement and an independent measurement of $\chi_c$ meson production in
$\pi^+ \pi^-$ and/or $K^+ K^-$ decay channels. Finally, we address the issue of
\J spin alignment.


title:
Nonlinearity of vacuum reggeons and exclusive diffractive production of
  vector mesons at HERA

abstract:
  The processes of exclusive photo- and electroproduction of vector mesons
$\rho^0$(770), $\phi$(1020) and $J/\psi$(3096) at collision energies $30
GeV<W<300 GeV$ and transferred momenta squared $0<-t<2 GeV^2$ are considered in
the framework of a phenomenological Regge-eikonal scheme with nonlinear Regge
trajectories in which their QCD asymptotic behavior is taken into account
explicitly. By comparison of available experimental data from ZEUS and H1
Collaborations with the model predictions it is demonstrated that corresponding
angular distributions and integrated cross-sections in the above-mentioned
kinematical range can be quantitatively described with use of two $C$-even
vacuum Regge trajectories. These are the "soft" pomeron dominating the high
energy reactions without a hard scale and the "hard" pomeron giving an
essential contribution to photo- and electroproduction of heavy vector mesons
and deeply virtual electroproduction of light vector mesons.


title:
Spectral density of an interacting dot coupled indirectly to conducting
  leads

abstract:
  We study the spectral density of electrons rho in an interacting quantum dot
(QD) with a hybridization lambda to a non-interacting QD, which in turn is
coupled to a non-interacting conduction band. The system corresponds to an
impurity Anderson model in which the conduction band has a Lorentzian density
of states of width Delta2.
  We solved the model using perturbation theory in the Coulomb repulsion U
(PTU) up to second order and a slave-boson mean-field approximation (SBMFA).
The PTU works surprisingly well near the exactly solvable limit Delta2 -> 0.
For fixed U and large enough lambda or small enough Delta2, the Kondo peak in
rho(omega) splits into two peaks. This splitting can be understood in terms of
weakly interacting quasiparticles. Before the splitting takes place the
universal properties of the model in the Kondo regime are lost. Using the
SBMFA, simple analytical expressions for the occurrence of split peaks are
obtained. For small or moderate Delta2, the side bands of rho(omega) have the
form of narrow resonances, that were missed in previous studies using the
numerical renormalization group. This technique also has shortcomings for
describing properly the split Kondo peaks. As the temperature is increased, the
intensity of the split Kondo peaks decreases, but it is not completely
suppressed at high temperatures.


title:
Outlining the Local Void with the Parkes HI ZOA and Galactic Bulge
  Surveys

abstract:
  The Parkes deep HI ZOA survey has been extended between 2002 and 2004 towards
higher latitudes in the Galactic Bulge region. This area of extreme star
crowding and high extinction levels remains impenetrable at any other waveband
regime.
  Preliminary results of the 3 dimensional distribution based on the combined
HI-surveys are presented. We focus on the extent and "content" of the Local
Void as outlined by these HI surveys, followed by a preliminary discussion of
the properties of the few galaxies detected in the Local Void.


title:
Search for Low Mass Exotic mesonic structures. Part I: experimental
  results

abstract:
  Recently, several papers discussed on the existence of a low mass new
structure at a mass close to M=214.3 MeV. It was suggested that the
$\Sigma^{+}$ disintegration: $\Sigma^{+}\to$pP$^{0}$, P$^{0}\to\mu^{-}\mu^{+}$
proceeds through an intermediate particle P$^{0}$ having such mass. The present
work intends to look at other new or available data, in order to observe the
eventual existence of small narrow peaks or shoulders in very low mesonic
masses. Indeed narrow structures were already extracted from various data in
dibaryons, baryons and mesons (at larger masses that those studied here).


title: Families intersecting on an interval

abstract:
  We shall be interested in the following Erdos-Ko-Rado-type question. Fix some
subset B of [n]. How large a family A of subsets of [n] can we find such that
the intersection of any two sets in A contains a cyclic translate (modulo n) of
B? Chung, Graham, Frankl and Shearer have proved that, in the case where B is a
block of length t, we can do no better than to take A to consist of all
supersets of B. We give an alternative proof of this result, which is in a
certain sense more 'direct'.


title:
Search for Low Mass Exotic mesonic structures. Part II: attempts to
  understand the experimental results

abstract:
  Our previous paper, part I of the same study, shows the different
experimental spectra used to conclude on the genuine existence of narrow,
weakly excited mesonic structures, having masses below and a little above the
pion (M=139.56 MeV) mass. This work \cite{previous} was instigated by the
observation, in the $\Sigma^{+}$ disintegration: $\Sigma^{+}\to$pP$^{0}$,
P$^{0}\to\mu^{-}\mu^{+}$ \cite{park}, of a narrow range of dimuon masses. The
authors conclude on the existence of a neutral intermediate state P$_{0}$, with
a mass M=214.3 MeV $\pm$ 0.5 MeV. We present here some attempts to understand
the possible nature of the structures observed in part I.


title: Right-Left Asymmetry of Radiation from Fission

abstract:
  The effect of the right-left asymmetry is considered in the predicted earlier
electric dipole radiation from fission fragments arising due to the
Strutinski-Denisov induced polarisation mechanism. The magnitude of the
asymmetry parameter is on the level of 10^-3. That is in agreement with the
recent experimental data on the radiative ROT effect in ^{235}U fission induced
by cold polarised neutrons.


title:
Andrzej Pekalski networks of scientific interests with internal degrees
  of freedom through self-citation analysis

abstract:
  Old and recent theoretical works by Andrzej Pekalski (APE) are recalled as
possible sources of interest for describing network formation and clustering in
complex (scientific) communities, through self-organisation and percolation
processes. Emphasis is placed on APE self-citation network over four decades.
The method is that used for detecting scientists field mobility by focusing on
author's self-citation, co-authorships and article topics networks as in [1,2].
It is shown that APE's self-citation patterns reveal important information on
APE interest for research topics over time as well as APE engagement on
different scientific topics and in different networks of collaboration. Its
interesting complexity results from "degrees of freedom" and external fields
leading to so called internal shock resistance. It is found that APE network of
scientific interests belongs to independent clusters and occurs through rare or
drastic events as in irreversible "preferential attachment processes", similar
to those found in usual mechanics and thermodynamics phase transitions.


title:
Absence of fermionic quasi-particles in the superfluid state of the
  attractive Fermi gas

abstract:
  We calculate the effect of order parameter fluctuations on the fermionic
single-particle excitations in the superfluid state of neutral fermions
interacting with short range attractive forces. We show that in dimensions D
\leq 3 the singular effective interaction between the fermions mediated by the
gapless Bogoliubov-Anderson mode prohibits the existence of well-defined
quasi-particles. We explicitly calculate the single-particle spectral function
in the BEC regime in D=3 and show that in this case the quasi-particle residue
and the density of states are logarithmically suppressed.


title: A complex periodic QES potential and exceptional points

abstract:
  We show that the complex $\cal PT$-symmetric periodic potential $V(x) = -
({\rm i} \xi \sin 2x + N)^2$, where $\xi$ is real and $N$ is a positive
integer, is quasi-exactly solvable. For odd values of $N \ge 3$, it may lead to
exceptional points depending upon the strength of the coupling parameter $\xi$.
The corresponding Schr\"odinger equation is also shown to go over to the
Mathieu equation asymptotically. The limiting value of the exceptional points
derived in our scheme is consistent with known branch-point singularities of
the Mathieu equation.


title:
Kondo Universal Scaling for a Quantum Dot Coupled to Superconducting
  Leads

abstract:
  We study competition between the Kondo effect and superconductivity in a
single self-assembled InAs quantum dot contacted with Al lateral electrodes.
Due to Kondo enhancement of Andreev reflections the zero-bias anomaly develops
sidepeaks, separated by the superconducting gap energy Delta. For ten valleys
of different Kondo temperature T_K we tune the gap Delta with an external
magnetic field. We find that the zero-bias conductance in each case collapses
onto a single curve with Delta/kT_K as the only relevant energy scale,
providing experimental evidence for universal scaling in this system.


title:
Observational evidence for the origin of X-ray sources in globular
  clusters

abstract:
  Low-mass X-ray binaries, recycled pulsars, cataclysmic variables and
magnetically active binaries are observed as X-ray sources in globular
clusters. We discuss the classification of these systems, and find that some
presumed active binaries are brighter than expected. We discuss a new
statistical method to determine from observations how the formation of X-ray
sources depends on the number of stellar encounters and/or on the cluster mass.
We show that cluster mass is not a proxy for the encounter number, and that
optical identifications are essential in proving the presence of primordial
binaries among the low-luminosity X-ray sources.


title:
The dependence of the viscosity-parameter on the disk scale height
  profile

abstract:
  It is shown that the height scale for accretion disks is a constant whenever
hydrostatic equilibrium and sub-sonic turbulence regime hold in the disk. In
order to have a variable height scale, processes that do contribute with an
extra term to the continuity equation are needed. This makes the viscosity
parameter much greater in the outer region and much smaller in the inner
region. Under these circumstances, turbulence is a presumable source of
viscosity in the disk.


title:
Spin ladder compound Pb(0.55)Cd(0.45)V(2)O(5): synthesis and
  investigation

abstract:
  The complex oxide Pb(0.55)Cd(0.45)V(2)O(5) was synthesized and investigated
by means of X-ray powder diffraction, electron diffraction, magnetic
susceptibility measurements and band structure calculations. Its structure is
similar to that of MV(2)O(5) compounds (M = Na, Ca) giving rise to a spin
system of coupled S=1/2 two-leg ladders. Magnetic susceptibility measurements
reveal a spin gap-like behavior with \Delta ~ 270 K and a spin singlet ground
state. Band structure calculations suggest Pb(0.55)Cd(0.45)V(2)O(5) to be a
system of weakly coupled dimers in perfect agreement with the experimental
data. Pb(0.55)Cd(0.45)V(2)O(5) provides an example of the modification of the
spin system in layered vanadium oxides by cation substitution. Simple
correlations between the cation size, geometrical parameters and exchange
integrals for the MV(2)O(5)-type oxides are established and discussed.


title: Fractional Statistical Mechanics

abstract:
  The Liouville and first Bogoliubov hierarchy equations with derivatives of
noninteger order are derived. The fractional Liouville equation is obtained
from the conservation of probability to find a system in a fractional volume
element. This equation is used to obtain Bogoliubov hierarchy and fractional
kinetic equations with fractional derivatives. Statistical mechanics of
fractional generalization of the Hamiltonian systems is discussed. Liouville
and Bogoliubov equations with fractional coordinate and momenta derivatives are
considered as a basis to derive fractional kinetic equations. The
Fokker-Planck-Zaslavsky equation that has fractional phase-space derivatives is
obtained from fractional Bogoliubov equation. The linear fractional kinetic
equation for distribution of the charged particles is considered.


title: Initial Observations of Sunspot Oscillations Excited by Solar Flare

abstract:
  Observations of a large solar flare of December 13, 2006, using Solar Optical
Telescope (SOT) on Hinode spacecraft revealed high-frequency oscillations
excited by the flare in the sunspot chromosphere. These oscillations are
observed in the region of strong magnetic field of the sunspot umbra, and may
provide a new diagnostic tool for probing the structure of sunspots and
understanding physical processes in solar flares.


title: Proceedings of the Second International Workshop on Eta Meson Physics

abstract:
  These are the proceedings of the Second International Workshop on Eta Meson
Physics held in May 10-11, 2007, at the resort Peniscola in Spain. The workshop
was focused on topics regarding eta and eta' -meson production and decays
physics of common interest in the EU EtaMesonNet network.


title: Effects of self-phase modulation on weak nonlinear optical quantum gates

abstract:
  A possible two-qubit gate for optical quantum computing is the parity gate
based on the weak Kerr effect. Two photonic qubits modulate the phase of a
coherent state, and a quadrature measurement of the coherent state reveals the
parity of the two qubits without destroying the photons. This can be used to
create so-called cluster states, a universal resource for quantum computing.
Here, the effect of self-phase modulation on the parity gate is studied,
introducing generating functions for the Wigner function of a modulated
coherent state. For materials with non-EIT-based Kerr nonlinearities, there is
typically a self-phase modulation that is half the magnitude of the cross-phase
modulation. Therefore, this effect cannot be ignored. It is shown that for a
large class of physical implementations of the phase modulation, the quadrature
measurement cannot distinguish between odd and even parity. Consequently, weak
nonlinear parity gates must be implemented with physical systems where the
self-phase modulation is negligable.


title:
The HELLAS2XMM survey: XI. Unveiling the nature of X-ray Bright
  Optically Normal Galaxies

abstract:
  X-ray Bright Optically Normal Galaxies (XBONGs) constitute a small but not
negligible fraction of hard X-ray selected sources in recent Chandra and
XMM-Newton surveys. Even though several possibilities were proposed to explain
why a relatively luminous hard X-ray source does not leave any significant
signature of its presence in terms of optical emission lines, the nature of
XBONGs is still subject of debate. We aim to a better understanding of their
nature by means of a multiwavelength and morphological analysis of a small
sample of these sources. Good-quality photometric near-infrared data
(ISAAC/VLT) of four low-redshift (z=0.1-0.3) XBONGs, selected from the
HELLAS2XMM survey, have been used to search for the presence of the putative
nucleus, applying the surface-brightness decomposition technique through the
least-squares fitting program GALFIT. The surface brightness decomposition
allows us to reveal a nuclear point-like source, likely to be responsible of
the X-ray emission, in two out of the four sources. The results indicate that
moderate amounts of gas and dust, covering a large solid angle (possibly 4pi)
at the nuclear source, combined with the low nuclear activity, may explain the
lack of optical emission lines. The third XBONG is associated with an X-ray
extended source and no nuclear excess is detected in the near infrared at the
limits of our observations. The last source is associated to a close (d< 1
arcsec) double system and the fitting procedure cannot achieve a firm
conclusion.


title: Comparing Infrared Dirac-Born-Infeld Brane Inflation to Observations

abstract:
  We compare the Infrared Dirac-Born-Infeld (IR DBI) brane inflation model to
observations using a Bayesian analysis. The current data cannot distinguish it
from the \LambdaCDM model, but is able to give interesting constraints on
various microscopic parameters including the mass of the brane moduli
potential, the fundamental string scale, the charge or warp factor of throats,
and the number of the mobile branes. We quantify some distinctive testable
predictions with stringy signatures, such as the large non-Gaussianity, and the
large, but regional, running of the spectral index. These results illustrate
how we may be able to probe aspects of string theory using cosmological
observations.


title: Deflation Methods in Fermion Inverters

abstract:
  I will review recent developments in matrix deflation methods, by Ronald
Morgan/Walter Wilcox, Andreas Stathopoulos/Konstantinos Orginos, and Martin
L\"uscher, with application to lattice QCD fermion inversion. I will begin with
a short review of deflation-related work in the field. The Morgan/Wilcox
algorithms using GMRES and BiCGStab for deflation will be described. Typical
results for quenched (Wilson and twisted mass) and dynamical configurations
(CP-PACS and ETMC) will be displayed and discussed. I will outline how
inclusion of multiple right-hand sides and multiple shifts can be accommodated
within versions of these methods. I will also review deflation methods based on
Conjugate Gradient introduced by Stathopoulos and Orginos for hermitian systems
with multiple right-hand sides as well as L\"uscher's non-hermitian domain
decomposition algorithm using Generalized Conjugate Residual.}


title: From multiple integrals to Fredholm determinants

abstract:
  We consider a multiple integral representation for the finite temperature
density-density correlation functions of the one-dimensional Bose gas with
delta function interaction in the limits of infinite and vanishing repulsion.
In the former case a known Fredholm determinant is recovered. In the latter
case a similar expression appears with permanents replacing determinants.

categories: math-ph cond-mat.stat-mech hep-th math.MP


title: Comment on "Solving the mystery of booming sand dunes"

abstract:
  We show here that the standard physical model used by Vriend et al. to
analyse seismograph data, namely a non-dispersive bulk propagation, does not
apply to the surface layer of sand dunes. According to several experimental,
theoretical and field results, the only possible propagation of sound waves in
a dry sand bed under gravity is through an infinite, yet discrete, number of
dispersive surface modes. Besides, we present a series of evidences, most of
which have already been published in the literature, that the frequency of
booming avalanches is not controlled by any resonance as argued in this
article. In particular, plotting the data provided by Vriend et al. as a table,
it turns out that they do not present any correlation between the booming
frequency and their estimate of the resonant frequency.


title: Crossings and Nestings of Two Edges in Set Partitions

abstract:
  Let $\pi$ and $\lambda$ be two set partitions with the same number of blocks.
Assume $\pi$ is a partition of $[n]$.
  For any integer $l, m \geq 0$, let $\mathcal{T}(\pi, l)$ be the set of
partitions of $[n+l]$ whose restrictions to the last $n$ elements are
isomorphic to $\pi$, and $\mathcal{T}(\pi, l, m)$ the subset of
$\mathcal{T}(\pi,l)$ consisting of those partitions with exactly $m$ blocks.
Similarly define $\mathcal{T}(\lambda, l)$ and $\mathcal{T}(\lambda, l,m)$. We
prove that if the statistic $cr$ ($ne$), the number of crossings (nestings) of
two edges, coincides on the sets $\mathcal{T}(\pi, l)$ and
$\mathcal{T}(\lambda, l)$ for $l =0, 1$, then it coincides on $\mathcal{T}(\pi,
l,m)$ and $\mathcal{T}(\lambda, l,m)$ for all $l, m \geq 0$. These results
extend the ones obtained by Klazar on the distribution of crossings and
nestings for matchings.


title: High pressure Raman study of La$_{1-x}$Ca$_x$MnO$_{3-\delta}$ manganites

abstract:
  We report on a high-pressure Raman study on two members of the
La$_{1-x}$Ca$_x$MnO$_{3-\delta}$ manganite family ($x=0.20$, $\delta=0$ and
$\delta=0.08$). The results obtained for the $\delta=0$ sample show a different
behavior in the low and high pressure regimes ascribed to the onset of a new
pressure-activated interaction previously invoked in other manganite compounds.
The comparison of our results with literature data gives further support to the
identification of the Jahn-Teller active stretching mode and shows that
pressure-induced octahedral symmetrization is more effective in systems
exhibiting a lower metallic character. On the contrary the new interaction sets
in at pressure which decreases on increasing the metallic character of the
system indicating a relevant role of the Mn-Mn hopping integral in its
activation.


title: Spacelike Singularities and Hidden Symmetries of Gravity

abstract:
  We review the intimate connection between (super-)gravity close to a
spacelike singularity (the "BKL-limit") and the theory of Lorentzian Kac-Moody
algebras. We show that in this limit the gravitational theory can be
reformulated in terms of billiard motion in a region of hyperbolic space,
revealing that the dynamics is completely determined by a (possibly infinite)
sequence of reflections, which are elements of a Lorentzian Coxeter group. Such
Coxeter groups are the Weyl groups of infinite-dimensional Kac-Moody algebras,
suggesting that these algebras yield symmetries of gravitational theories. Our
presentation is aimed to be a self-contained and comprehensive treatment of the
subject, with all the relevant mathematical background material introduced and
explained in detail. We also review attempts at making the infinite-dimensional
symmetries manifest, through the construction of a geodesic sigma model based
on a Lorentzian Kac-Moody algebra. An explicit example is provided for the case
of the hyperbolic algebra E10, which is conjectured to be an underlying
symmetry of M-theory. Illustrations of this conjecture are also discussed in
the context of cosmological solutions to eleven-dimensional supergravity.


title: Electronic Correlations in Double Quantum Dots

abstract:
  We present a study of the electronic structure of two laterally coupled
gaussian quantum dots filled with two particles. The exact diagonalization
method has been used in order to inspect the spatial correlations and examine
the particular spin singlet-triplet configurations for different coupling
degrees between quantum dots. The outcome of our research shows this structure
to have highly modifiable properties promoting it as an interesting quantum
device, showing the possible use of this states as a quantum bit gate.


title:
Hadron Structure from Inclusive and Exclusive Cross-Sections in ep
  Scattering

abstract:
  The contribution of both inclusive and exclusive cross-section data from HERA
to our knowledge of parton distribution functions is reviewed and future
prospects are outlined.


title:
Full one-loop corrections to the relic density in the MSSM: A few
  examples

abstract:
  We show the impact of the electroweak, and in one instance the QCD, one-loop
corrections on the relic density of dark matter in the MSSM which is provided
by the lightest neutralino. We cover here some of the most important scenarii:
annihilation into fermions for a bino-like neutralino, annihilation involving
gauge bosons in the case of a mixed neutralino, the neutralino-stau
co-annihilation region and annihilation into a bottom quark pair. The
corrections can be large and should be taken into account in view of the
present and forthcoming increasing precision on the relic density measurements.
Our calculations are made possible thanks to a newly developed automatic tool
for the calculation at one-loop of any process in the MSSM. We have implemented
a complete on-shell gauge invariant renormalisation scheme, with the
possibility of switching to other schemes. In particular we will report on the
impact of different renormalisation schemes for tan beta.


title:
The approach to a superconductor-to-Bose-insulator transition in
  disordered films

abstract:
  Through a detailed study of scaling near the magnetic field-tuned
superconductor-to-insulator transition in strongly disordered films, we find
that results for a variety of materials can be collapsed onto a single phase
diagram. The data display two clear branches, one with weak disorder and an
intervening metallic phase, the other with strong disorder. Along the strongly
disordered branch, the resistance at the critical point approaches $R_Q =
h/4e^2$ and the scaling of the resistance is consistent with quantum
percolation, and therefore with the predictions of the dirty boson model.


title: Spherically Symmetric Solutions in Macroscopic Gravity

abstract:
  Schwarzschild's solution to the Einstein Field Equations was one of the first
and most important solutions that lead to the understanding and important
experimental tests of Einstein's theory of General Relativity. However,
Schwarzschild's solution is essentially based on an ideal theory of
gravitation, where all inhomogeneities are ignored. Therefore, any
generalization of the Schwarzschild solution should take into account the
effects of small perturbations that may be present in the gravitational field.
The theory of Macroscopic Gravity characterizes the effects of the
inhomogeneities through a non-perturbative and covariant averaging procedure.
With similar assumptions on the geometry and matter content, a solution to the
averaged field equations as dictated by Macroscopic Gravity are derived. The
resulting solution provides a possible explanation for the flattening of
galactic rotation curves, illustrating that Dark Matter is not real but may
only be the result of averaging inhomogeneities in a spherically symmetric
background.


title: The motion of a charged particle in Kalusa-Klein manifolds

abstract:
  In this paper we use Jacobi fields to describe the motion of a charged
particle in the classical gravitational, electromagnetic, and Yang-Mills
fields.


title: Thermodynamics of Charged BTZ Black Holes and Effective String Theory

abstract:
  In this paper we study the first law of thermodynamics for the (2+1)
dimensional charged BTZ black hole considering a pair of thermodinamical
systems constructed with the two horizons of this solution. We show that these
two systems are similar to the right and left movers of string theory and that
the temperature associated with the black hole is the harmonic mean of the
temperatures associated with these two systems.


title: Fractional APT in QCD in the Euclidean and Minkowski regions

abstract:
  We describe the development of Analytic Perturbation Theory (APT) in QCD,
called Fractional APT (FAPT), which has been suggested to apply the
renormalization group evolution and QCD factorization technique in the
framework of APT.


title: Multi-Pion Systems in Lattice QCD and the Three-Pion Interaction

abstract:
  The ground-state energies of 2, 3, 4 and 5 \pi^+'s in a spatial volume V (2.5
fm)^3 are computed with lattice QCD. By eliminating the leading contribution
from three-\pi^+ interactions, particular combinations of these n-\pi^+
ground-state energies provide precise extractions of the \pi^+\pi^+ scattering
length in agreement with that obtained from calculations involving only two
\pi^+'s. The three-\pi^+ interaction can be isolated by forming other
combinations of the n-\pi^+ ground-state energies. We find a result that is
consistent with a repulsive three-\pi^+ interaction for m_\pi < 352 MeV.


title: Precision abundance analysis of bright HII galaxies

abstract:
  We present high signal-to-noise spectrophotometric observations of seven
luminous HII galaxies. The observations have been made with the use of a
double-arm spectrograph which provides spectra with a wide wavelength coverage,
from 3400 to 10400\AA free of second order effects, of exactly the same region
of a given galaxy. These observations are analysed applying a methodology
designed to obtain accurate elemental abundances of oxygen, sulphur, nitrogen,
neon, argon and iron in the ionized gas. Four electron temperatures and one
electron density are derived from the observed forbidden line ratios using the
five-level atom approximation. For our best objects errors of 1% in
t_e([OIII]), 3% in t_e([OII]) and 5% in t_e([SIII]) are achieved with a
resulting accuracy of 7% in total oxygen abundances, O/H.
  The ionisation structure of the nebulae can be mapped by the theoretical
oxygen and sulphur ionic ratios, on the one side, and the corresponding
observed emission line ratios, on the other -- the \eta and \eta' plots --. The
combination of both is shown to provide a means to test photo-ionisation model
sequences currently applied to derive elemental abundances in HII galaxies.


title: IIB solutions with N>28 Killing spinors are maximally supersymmetric

abstract:
  We show that all IIB supergravity backgrounds which admit more than 28
Killing spinors are maximally supersymmetric. In particular, we find that for
all N>28 backgrounds the supercovariant curvature vanishes, and that the
quotients of maximally supersymmetric backgrounds either preserve all 32 or
N<29 supersymmetries.


title: Structural efficiency of percolation landscapes in flow networks

abstract:
  Complex networks characterized by global transport processes rely on the
presence of directed paths from input to output nodes and edges, which organize
in characteristic linked components. The analysis of such network-spanning
structures in the framework of percolation theory, and in particular the key
role of edge interfaces bridging the communication between core and periphery,
allow us to shed light on the structural properties of real and theoretical
flow networks, and to define criteria and quantities to characterize their
efficiency at the interplay between structure and functionality. In particular,
it is possible to assess that an optimal flow network should look like a "hairy
ball", so to minimize bottleneck effects and the sensitivity to failures.
Moreover, the thorough analysis of two real networks, the Internet
customer-provider set of relationships at the autonomous system level and the
nervous system of the worm Caenorhabditis elegans --that have been shaped by
very different dynamics and in very different time-scales--, reveals that
whereas biological evolution has selected a structure close to the optimal
layout, market competition does not necessarily tend toward the most customer
efficient architecture.


title: Structural phase transitions in low-dimensional ion crystals

abstract:
  A chain of singly-charged particles, confined by a harmonic potential,
exhibits a sudden transition to a zigzag configuration when the radial
potential reaches a critical value, depending on the particle number. This
structural change is a phase transition of second order, whose order parameter
is the crystal displacement from the chain axis. We study analytically the
transition using Landau theory and find full agreement with numerical
predictions by [J. Schiffer Phys. Rev. Lett. 70, 818 (1993)] and [Piacente et
al Phys. Rev. B 69, 045324 (2004)]. Our theory allows us to determine
analytically the system's behaviour at the transition point.


title:
Next-to-leading order predictions for WW + 1 jet distributions at the
  LHC

abstract:
  We present numerical results for the production of a $W^+W^-$ pair in
association with a jet at the LHC in QCD at next-to-leading order (NLO). We
include effects of the decay of the massive vector bosons into leptons with
spin correlations and contributions from the third generation of massive
quarks. The calculation is performed using a semi-numerical method for the
virtual corrections, and is implemented in MCFM. In addition to its importance
{\it per se} as a test of the Standard Model, this process is an important
background to searches for the Higgs boson and to many new physics searches. As
an example, we study the impact of NLO corrections to $W^+W^-+$ jet production
on the search for a Higgs boson at the LHC.


title: Stable and Metastable Vacua in Brane Constructions of SQCD

abstract:
  In a recent paper [1] we showed that N=1 supersymmetric QCD in the presence
of certain superpotential deformations has a rich landscape of supersymmetric
and non-supersymmetric vacua. In this paper we embed this theory in string
theory as a low energy theory of intersecting NS and D-branes. We find that in
the region of parameter space of brane configurations that can be reliably
studied using classical string theory, the vacuum structure is qualitatively
similar to that in the field theory regime. Effects that in field theory come
from one loop corrections arise in string theory as classical gravitational
effects. The brane construction provides a useful guide to the structure of
stable and metastable gauge theory vacua.


title:
A Search for NIR Molecular Hydrogen Emission in the CTTS LkHa 264 and
  the debris disk 49 Cet

abstract:
  We report on the first results of a search for H2 emission from
protoplanetary disks using CRIRES, ESO's new VLT high resolution NIR
spectrograph. We observed the CTTS LkHa 264 and the debris disk 49 Cet, and
searched for the 1-0 S(1), 1-0 S(0) and 2-1 S(1) H2 emission lines. The H2 line
at 2.1218 micron is detected in LkHa 264. Our CRIRES spectra reveal the
previously observed but not detected H2 line at 2.2233 micron in LkHa 264. An
upper limit on the 2-1 S(1) H2 line flux in LkHalpha 264 is derived. These
observations are the first simultaneous detection of 1-0 S(1) and 1-0 S(0) H2
emission from a protoplanetary disk. 49 Cet does not exhibit H2 emission in any
of the three observed lines. There are a few lunar masses of optically thin hot
H2 in the inner disk (~0.1 AU) of LkHa 264, and less than a tenth of a lunar
mass of hot H2 in the inner disk of 49 Cet. The measured 1-0 S(0)/1-0 S(1) and
2-1 S(1)/1-0 S(1) line ratios in LkHa 264 indicate that the H2 emitting gas is
at T<1500 K and that the H2 is most likely thermally excited by UV photons.
Modeling of the shape of the line suggests that the disk should be seen close
to face-on (i<35). A comparative analysis of the physical properties of CTTS in
which the H2 1-0 S(1) line has been detected and non-detected indicates that
the presence of H2 emission is correlated with the magnitude of the UV excess
and the strength of the Halpha line. The lack of H2 emission in the NIR spectra
of 49 Cet and the absence of Halpha emission suggest that the gas in the inner
disk of 49 Cet has dissipated. The disk surrounding 49 Cet should have an inner
hole.


title:
Computations with finite index subgroups of $PSL_2(\mathbb Z)$ using
  Farey Symbols

abstract:
  Finite index subgroups of the modular group are of great arithmetic
importance. Farey symbols, introduced by Ravi Kulkarni in 1991, are a tool for
working with these groups. Given such a group $\Gamma$, a Farey symbol for
$\Gamma$ is a certain finite sequence of rational numbers (representing
vertices of a fundamental domain of $\Gamma$) together with pairing information
for the edges between the vertices. They are a compact way of encoding the
information about the group and they provide a simple way to do calculations
with the group. For example: calculating an independent set of generators and
decomposing group elements into a word in these generators, finding coset
representatives, elliptic points, and genus of the group, testing if the group
is congruence, etc. In this expository article, we will discuss Farey Symbols
and explicit algorithms for working with them.


title:
High-J v=0 SiS Maser Emission in IRC+10216: A New Case of Infrared
  Overlaps

abstract:
  We report on the first detection of maser emission in the J=11-10, J=14-13
and J=15-14 transitions of the v=0 vibrational state of SiS toward the C-rich
star IRC+10216. These masers seem to be produced in the very inhomogeneous
region between the star and the inner dust formation zone, placed at 5-7 R*,
with expansion velocities below 10 km/s. We interpret the pumping mechanism as
due to overlaps between v=1-0 ro-vibrational lines of SiS and mid-IR lines of
C2H2, HCN and their 13C isotopologues. The large number of overlaps found
suggests the existence of strong masers for high-J v=0 and v=1 SiS transitions,
located in the submillimeter range. In addition, it could be possible to find
several rotational lines of the SiS isotopologues displaying maser emission.


title:
A glass-like behavior in the low-temperature specific heat is a natural
  property of any real crystal

abstract:
  We provide a rigorous calculation of the free energy of a non-metallic
crystal containing a small concentration of defects. The low-temperature
leading contribution is found to be $\propto T^2$. This further gives a
linear-in-$T$ low-temperature specific heat as that exhibited by glasses. These
results also show that, similarly to what happens in glasses, the
long-wavelength spectrum of a nearly perfect crystal does not suffice to
determine its low-temperature behavior.


title: Warped Phenomenology in the Holographic Basis

abstract:
  The holographic basis is a novel tool which allows for a quantitative
description of elementary/composite mixing in holographic duals of warped
models. We apply this tool to bulk fermions in a slice of AdS_5 and determine
the precise admixture of elementary source field and composite resonances
forming the Standard Model fermions. In particular, for the phenomenologically
important case of an IR localized right-handed top quark, we show that the
massless eigenstate is approximately a 50/50 elementary-composite admixture. We
also translate, in a simple yet quantitative manner, several of the
phenomenological successes enjoyed by warped models to the language of partial
compositeness.


title:
Comparing and calibrating black hole mass estimators for distant active
  galactic nuclei

abstract:
  Black hole mass is a fundamental property of active galactic nuclei (AGNs).
In the distant universe, black hole mass is commonly estimated using the MgII,
Hbeta, or Halpha emission line widths and the optical/UV continuum or line
luminosities, as proxies for the characteristic velocity and size of the
broad-line region. Although they all have a common calibration in the local
universe, a number of different recipes are currently used in the literature.
It is important to verify the relative accuracy and consistency of the recipes,
as systematic changes could mimic evolutionary trends when comparing various
samples. At z=0.36, all three lines can be observed at optical wavelengths,
providing a unique opportunity to compare different empirical recipes. We use
spectra from the Keck Telescope and the Sloan Digital Sky Survey to compare
black hole mass estimators for a sample of nineteen AGNs at this redshift. We
compare popular recipes available from the literature, finding that mass
estimates can differ up to 0.38+-0.05 dex in the mean (or 0.13+-0.05 dex, if
the same virial coefficient is adopted). Finally, we provide a set of 30
internally self consistent recipes for determining black hole mass from a
variety of observables. The intrinsic scatter between cross-calibrated recipes
is in the range 0.1-0.3 dex. This should be considered as a lower limit to the
uncertainty of the black hole mass estimators.


title: A Catalogue of Be Stars in the Direction of the Galactic Bulge

abstract:
  Detailed studies of Be stars in environments with different metallicities
like the Magellanic Clouds or the Galactic bulge are necessary to understand
the formation and evolution mechanisms of the circumstellar disks. However, a
detailed study of Be stars in the direction of the bulge of our own galaxy has
not been performed until now. We report the first systematic search for Be star
candidates in the direction of the Galactic Bulge. We present the catalogue,
give a brief description of the stellar variability seen, and show some light
curve examples. We searched for stars matching specific criteria of magnitude,
color and variability in the I band. Our search was conducted on the 48 OGLE II
fields of the Galactic Bulge.This search has resulted in 29053 Be star
candidates, 198 of them showing periodic light variations. Nearly 1500 stars in
this final sample are almost certainly Be stars, providing an ideal sample for
spectroscopic multiobject follow-up studies.


title: HAT-P-5b: A Jupiter-like hot Jupiter Transiting a Bright Star

abstract:
  We report the discovery of a planet transiting a moderately bright (V =
12.00) G star, with an orbital period of 2.788491 +/-0.000025 days. From the
transit light curve we determine that the radius of the planet is Rp = 1.257
+/- 0.053 RJup. HAT-P-5b has a mass of Mp = 1.06 +/- 0.11 MJup, similar to the
average mass of previously-known transiting exoplanets, and a density of rho =
0.66 +/- 0.11 g cm^-3 . We find that the center of transit is Tc =
2,454,241.77663 +/- 0.00022 (HJD), and the total transit duration is 0.1217 +/-
0.0012 days.


title: An explicit universal cycle for the (n-1)-permutations of an n-set

abstract:
  We show how to construct an explicit Hamilton cycle in the directed Cayley
graph Cay({\sigma_n, sigma_{n-1}} : \mathbb{S}_n), where \sigma_k = (1 2 >...
k). The existence of such cycles was shown by Jackson (Discrete Mathematics,
149 (1996) 123-129) but the proof only shows that a certain directed graph is
Eulerian, and Knuth (Volume 4 Fascicle 2, Generating All Tuples and
Permutations (2005)) asks for an explicit construction. We show that a simple
recursion describes our Hamilton cycle and that the cycle can be generated by
an iterative algorithm that uses O(n) space. Moreover, the algorithm produces
each successive edge of the cycle in constant time; such algorithms are said to
be loopless.


title: Dark Matter Phenomenology of GUT-less SUSY Breaking

abstract:
  We study models in which supersymmetry breaking appears at an intermediate
scale, M_in, below the GUT scale. That is, that the soft supersymmetry-breaking
parameters of the MSSM are universal at M_in. We demand that the lightest
neutralino be the LSP, and that the relic neutralino density not conflict with
measurements by WMAP and others, and study the morphology of this constraint as
the universality scale is reduced from the GUT scale. At moderate values of
M_in, we find that the allowed regions of the (m_1/2,m_0) plane are squeezed by
the requirements of electroweak symmetry breaking and that the lightest
neutralino be the LSP, whereas the constraint on the relic density is less
severe. At very low M_in, the electroweak vacuum conditions become the dominant
constraint, and a secondary source of astrophysical cold dark matter would be
necessary to explain the measured relic density for nearly all values of the
soft SUSY-breaking parameters and tan(beta).


title: Killing graphs with prescribed mean curvature and Riemannian submersions

abstract:
  It is proved the existence and uniqueness of graphs with prescribed mean
curvature in Riemannian submersions fibered by flow lines of a vertical Killing
vector field.


title: Smooth deformations of piecewise expanding unimodal maps

abstract:
  In the space of C^k piecewise expanding unimodal maps, k>=1, we characterize
the C^1 smooth families of maps where the topological dynamics does not change
(the "smooth deformations") as the families tangent to a continuous
distribution of codimension-one subspaces (the "horizontal" directions) in that
space. Furthermore such codimension-one subspaces are defined as the kernels of
an explicit class of linear functionals. As a consequence we show the existence
of C^{k-1+Lip} deformations tangent to every given C^k horizontal direction,
for k>=2.


title:
Stellar evolution through the ages: period variations in galactic RRab
  stars as derived from the GEOS database and TAROT telescopes

abstract:
  The theory of stellar evolution can be more closely tested if we have the
opportunity to measure new quantities. Nowadays, observations of galactic RR
Lyr stars are available on a time baseline exceeding 100 years. Therefore, we
can exploit the possibility of investigating period changes, continuing the
pioneering work started by V. P. Tsesevich in 1969. We collected the available
times of maximum brightness of the galactic RR Lyr stars in the GEOS RR Lyr
database. Moreover, we also started new observational projects, including
surveys with automated telescopes, to characterise the O-C diagrams better. The
database we built has proved to be a very powerful tool for tracing the period
variations through the ages. We analyzed 123 stars showing a clear O-C pattern
(constant, parabolic or erratic) by means of different least-squares methods.
Clear evidence of period increases or decreases at constant rates has been
found, suggesting evolutionary effects. The median values are beta=+0.14
day/Myr for the 27 stars showing a period increase and beta=-0.20 day/Myr for
the 21 stars showing a period decrease. The large number of RR Lyr stars
showing a period decrease (i.e., blueward evolution) is a new and intriguing
result. There is an excess of RR Lyr stars showing large, positive $\beta$
values. Moreover, the observed beta values are slightly larger than those
predicted by theoretical models.


title:
Control of nucleation and crystal growth of a silicate apatitic phase in
  a glassy matrix

abstract:
  Nucleation and growth of crystal in an oxide glass was studied in a Si B Al
Zr Nd Ca Na O system. The nucleation and growth process was monitored by
thermal analysis and isothermal experiments. For the Ca sample the
crystallization is homogeneous in the bulk showing a slow increase of
crystallinity as temperature increases. The Na rich sample on the other hand go
through several crystallization process in the bulk or from the surface,
leading to bigger crystals. The activation energy of the viscous flow and the
glass transition are of same magnitude when that of crystallization is a lot
smaller. Early diffusion of element is done with a mechanism different than the
configurational rearrangements of the liquid sate. The global density and small
shape of the crystals within the Ca rich matrix confirmed that it would be a
profitable waste form for minor actinides.