title:
On a method to calculate conductance by means of the Wigner function:
  two critical tests

abstract:
  We have implemented the linear response approximation of a method proposed to
compute the electron transport through correlated molecules based on the
time-independent Wigner function [P. Delaney and J. C. Greer, \prl {\bf 93},
36805 (2004)]. The results thus obtained for the zero-bias conductance through
quantum dot both without and with correlations demonstrate that this method is
either quantitatively nor qualitatively able to provide a correct physical
escription of the electric transport through nanosystems. We present an
analysis indicating that the failure is due to the manner of imposing the
boundary conditions, and that it cannot be simply remedied.


title: Gravitational renormalization of quantum field theory

abstract:
  We propose to include gravity in quantum field theory non-perturbatively, by
modifying the propagators so that each virtual particle in a Feynman graph move
in the space-time determined by the four-momenta of the other particles in the
same graph. By making additional working assumptions, we are able to put this
idea at work in a simplified context, and obtain a modified Feynman propagator
for the massless neutral scalar field. Our expression shows a suppression at
high momentum, strong enough to entail finite results, to all loop orders, for
processes involving at least two virtual particles.


title: Dynamical suppression of the spin-orbit interaction in hadrons

abstract:
  Spin-dependent interaction in hadrons is considered in the approach of the
QCD string. The string moment of inertia, which ensures the correct (inverse)
Regge slope 2*pi*sigma, is found to suppress the spin-orbit interaction. For
light quarks and moderate angular momenta the suppression constitutes around
25% whereas for large angular momenta the spin-orbit interaction is suppressed
by the factor L^(-2/5). For heavy quarks the effect manifests itself as a
string correction for the spin-dependent potential.


title: Examples of quantum commutants

abstract:
  We describe the notion of a quantum family of maps of a quantum space and
that of a quantum commutant of such a family. Quantum commutants are quantum
semigroups defined by a certain universal property. We give a few examples of
these objects acting on a classical $n$-point space and on the quantum space
underlying the algebra of two by two matrices. We show that some of the
resulting quantum semigroups are not compact quantum groups. The proof of one
result touches on an interesting problem of the theory of compact quantum
groups.


title: Modification of nucleon properties in nuclear matter and finite nuclei

abstract:
  We present a model for the description of nuclear matter and finite nuclei,
and at the same time, for the study of medium modifications of nucleon
properties. The nucleons are described as nontopological solitons which
interact through the self-consistent exchange of scalar and vector mesons. The
model explicitly incorporates quark degrees of freedom into nuclear many-body
systems and provides satisfactory results on the nuclear properties. The
present model predicts a significant increase of the nucleon radius at normal
nuclear matter density. It is very interesting to see the nucleon properties
change from the nuclear surface to the nuclear interior.


title: Stretching chimeric DNA: a test for the putative S-form

abstract:
  Double-stranded DNA `overstretches' at a pulling force of about 65 pN,
increasing in length by a factor of 1.7. The nature of the overstretched state
is unknown, despite its considerable importance for DNA's biological function
and technological application. Overstretching is thought by some to be a
force-induced denaturation, and by others to consist of a transition to an
elongated, hybridized state called S-DNA. Within a statistical mechanical model
we consider the effect upon overstretching of extreme sequence heterogeneity.
`Chimeric' sequences possessing halves of markedly different AT composition
elongate under fixed external conditions via distinct, spatially segregated
transitions. The corresponding force-extension data display two plateaux at
forces whose difference varies with pulling rate in a manner that depends
qualitatively upon whether the hybridized S-form is accessible. This
observation implies a test for S-DNA that could be performed in experiment. Our
results suggest that qualitatively different, spatially segregated
conformational transitions can occur at a single thermodynamic state within
single molecules of DNA.


title:
High-Probability Quantum State Transfer in the Alternating Open Chains
  of 1/2 Spins with XY Hamiltonian

abstract:
  This paper concerns the problem of non-ideal state transfer along the
alternating open chain of spins $s=1/2$ with XY Hamiltonian. It is found that
the state transfer along the chain with even number of spins $N$ ($N=4,6,8$)
may be realized with high probability. Privilege of even $N$ in comparison with
odd $N$ is demonstrated.


title:
Strong peak points and strongly norm attaining points with applications
  to denseness and polynomial numerical indices

abstract:
  Using the variational method, it is shown that the set of all strong peak
functions in a closed algebra $A$ of $C_b(K)$ is dense if and only if the set
of all strong peak points is a norming subset of $A$. As a corollary we can
induce the denseness of strong peak functions on other certain spaces. In case
that a set of uniformly strongly exposed points of a Banach space $X$ is a
norming subset of $\mathcal{P}({}^n X)$, then the set of all strongly norm
attaining elements in $\mathcal{P}({}^n X)$ is dense. In particular, the set of
all points at which the norm of $\mathcal{P}({}^n X)$ is Fr\'echet
differentiable is a dense $G_\delta$ subset.
  In the last part, using Reisner's graph theoretic-approach, we construct some
strongly norm attaining polynomials on a CL-space with an absolute norm. Then
we show that for a finite dimensional complex Banach space $X$ with an absolute
norm, its polynomial numerical indices are one if and only if $X$ is isometric
to $\ell_\infty^n$. Moreover, we give a characterization of the set of all
complex extreme points of the unit ball of a CL-space with an absolute norm.


title: On the binomial convolution of arithmetical functions

abstract:
  Let $n=\prod_p p^{\nu_p(n)}$ denote the canonical factorization of $n\in \N$.
The binomial convolution of arithmetical functions $f$ and $g$ is defined as
$(f\circ g)(n)=\sum_{d\mid n} (\prod_p \binom{\nu_p(n)}{\nu_p(d)}) f(d)g(n/d),$
where $\binom{a}{b}$ is the binomial coefficient. We provide properties of the
binomial convolution. We study the $\C$-algebra $({\cal A},+,\circ,\C)$,
characterizations of completely multiplicative functions, Selberg
multiplicative functions, exponential Dirichlet series, exponential generating
functions and a generalized binomial convolution leading to various
M\"obius-type inversion formulas. Throughout the paper we compare our results
with those of the Dirichlet convolution *. Our main result is that $({\cal
A},+,\circ,\C)$ is isomorphic to $({\cal A},+,*,\C)$. We also obtain a
"multiplicative" version of the multinomial theorem.


title: Complete and Consistent Non-Minimal String Corrections to Supergravity

abstract:
  We give a complete and consistent solution to string corrected (deformed),
D=10, N=1 supergravity as the non-minimal low energy limit of string theory. We
solve the Bianchi identities with suitable constraints to second order in the
string slope parameter. In so doing we pave the way for continuing the study of
the many applications of these results. We also modify, reaffirm and correct a
previously given incomplete solution, and we introduce an important adjustment
to the known first order results.


title:
Line bundles on spectral curves and the generalised Legendre transform
  construction of hyperkaehler metrics

abstract:
  An analogue of the correspondence between GL(k)-conjugacy classes of
matricial polynomials and line bundles is given for K-conjugacy classes, where
K is one of the following: maximal parabolic, maximal torus, GL(k-1) embedded
diagonally. The generalised Legendre transform construction of hyperkaehler
metrics is studied further, showing that many known hyperkaehler metrics
(including the ones on coadjoint orbits) arise in this way, and giving a large
class of new (pseudo-)hyperkaehler metrics, analogous to monopole metrics.


title: AGN Dusty Tori: I. Handling of Clumpy Media

abstract:
  According to unified schemes of Active Galactic Nuclei (AGN), the central
engine is surrounded by dusty, optically thick clouds in a toroidal structure.
We have recently developed a formalism that for the first time takes proper
account of the clumpy nature of the AGN torus. We now provide a detailed report
of our findings in a two-paper series. Here we present our general formalism
for radiative transfer in clumpy media and construct its building blocks for
the AGN problem -- the source functions of individual dusty clouds heated by
the AGN radiation field. We show that a fundamental difference from smooth
density distributions is that in a clumpy medium, a large range of dust
temperatures coexist at the same distance from the radiation central source.
This distinct property explains the low dust temperatures found close to the
nucleus of NGC1068 in 10 \mic interferometric observations. We find that
irrespective of the overall geometry, a clumpy dust distribution shows only
moderate variation in its spectral energy distribution, and the 10\mic\
absorption feature is never deep. Furthermore, the X-ray attenuating column
density is widely scattered around the column density that characterizes the IR
emission. All of these properties are characteristic of AGN observations. The
assembly of clouds into AGN tori and comparison with observations is presented
in the companion paper.


title: AGN Dusty Tori: II. Observational Implications of Clumpiness

abstract:
  From extensive radiative transfer calculations we find that clumpy torus
models with \No \about 5--15 dusty clouds along radial equatorial rays
successfully explain AGN infrared observations. The dust has standard Galactic
composition, with individual cloud optical depth \tV \about 30--100 at visual.
The models naturally explain the observed behavior of the 10\mic silicate
feature, in particular the lack of deep absorption features in AGN of any type.
The weak 10\mic emission feature tentatively detected in type 2 QSO can be
reproduced if in these sources \No drops to \about 2 or \tV exceeds \about 100.
The clouds angular distribution must have a soft-edge, e.g., Gaussian profile,
the radial distribution should decrease as $1/r$ or $1/r^2$. Compact tori can
explain all observations, in agreement with the recent interferometric evidence
that the ratio of the torus outer to inner radius is perhaps as small as \about
5--10. Clumpy torus models can produce nearly isotropic IR emission together
with highly anisotropic obscuration, as required by observations. In contrast
with strict variants of unification schemes where the viewing-angle uniquely
determines the classification of an AGN into type 1 or 2, clumpiness implies
that it is only a probabilistic effect; a source can display type 1 properties
even from directions close to the equatorial plane. The fraction of obscured
sources depends not only on the torus angular thickness but also on the cloud
number \No. The observed decrease of this fraction at increasing luminosity can
be explained with a decrease of either torus angular thickness or cloud number,
but only the latter option explains also the possible emergence of a 10\mic
emission feature in QSO2.


title:
Charge Independent(CI) and Charge Dependent(CD) correlations vs.
  Centrality from $\Delta \phi \Delta \eta$ Charged Pairs in Minimum Bias Au +
  Au Collisions at 200 Gev

abstract:
  We report high precision charged-particle pair (2-D) correlation analyses in
the space of $\Delta \phi$ (azimuth) and $\Delta \eta$ (pseudorapidity), for
minimum bias Au + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV as a function of
centrality (0-80%). The intermediate transverse momenta region chosen $0.8 <
p_t < 4.0$ GeV/c corresponds to an emission source size $\sim2$fm obtained from
HBT measurements and should resolve substructures at the scale of $\sim2$fm.
The difference and the sum of unlike-sign and like-sign charged pairs form
Charge Dependent (CD) correlations and Charge Independent (CI) correlations
respectively. The CD displays the initial correlation at hadronization of the
opposite sign pairs emitted from the same space-time region as modified by
further medium interactions before kinetic freeze-out. Our analysis of the CD
correlations shows approximately jet-like structure, independent of centrality
and is consistent with the initial correlation which is predicted by Pythia (or
HIJING) jets. The CI correlation displays the average structure of the
correlated emitting sources after kinetic freeze-out. For the most central
bins, the $\Delta \eta$ width of the CI correlation on the near side ($\Delta
\phi$ around $0^\circ$) is elongated by a factor $\sim$3 destroying the
jet-like symmetry. This elongation decreases continually with decreasing
centrality and essentially restores the jet-like symmetric structure in the
most peripheral bins. The Pythia and HIJING event generators together with a
QCD inspired Parton Bubble Model (PBM), which motivated this analysis, are used
to compare to our data. We discuss the arguments for substructure, surface
emission, and opacity in the central fireball region.


title: Conformation of Circular DNA in 2 Dimensions

abstract:
  The conformation of circular DNA molecules of various lengths adsorbed in a
2D conformation on a mica surface is studied. The results confirm the
conjecture that the critical exponent $\nu$ is topologically invariant and
equal to the SAW value (in the present case $\nu=3/4$), and that the topology
and dimensionality of the system strongly influences the cross-over between the
rigid regime and the self-avoiding regime at a scale $L\approx 8 \ell_p$.
Additionally, the bond correlation function scales with the molecular length
$L$ as predicted. For molecular lengths $L\leq5 \ell_p$, circular DNA behaves
like a stiff molecule with approximately elliptic shape.


title: Enhanced superconductivity in Hf-base metallic glasses

abstract:
  Systematic study of electrical resistivity of Hf_{100-x}Fe_x (x=20,25),
Hf_{100-x}Cu_x (x=30,40,50), and Ti_{65}Cu_{35} metallic glasses has been done
in the temperature range 0.3 K - 290 K, and in magnetic fields B <= 5 T. All
Hf-base alloys are superconducting with T_c >= 0.44 K, which is well above T_c
of pure crystalline Hf (0.13 K). From the initial slopes of the upper critical
fields, (dH_{c2}/dT)_{T_c}, and resistivities we determined the dressed
electronic densities of states, N_{\gamma}(E_F), for all alloys. Both T_c and
N_{\gamma}(E_F) decrease with increasing x (Fe and Cu content). The results are
compared with those for corresponding Zr-base metallic glasses and
ion-implanted Hf films.


title:
Scalar field-perfect fluid correspondence and nonlinear perturbation
  equations

abstract:
  The properties of dynamical Dark Energy (DE) and, in particular, the
possibility that it can form or contribute to stable inhomogeneities, have been
widely debated in recent literature, also in association to a possible coupling
between DE and Dark Matter (DM). In order to clarify this issue, in this paper
we present a general framework for the study of the nonlinear phases of
structure formation, showing the equivalence between two possible descriptions
of DE: a scalar field \phi self-interacting through a potential V(\phi) and a
perfect fluid with an assigned negative equation of state w(a). This enables us
to show that, in the presence of coupling, the mass of DE quanta may increase
where large DM condensations are present, so that also DE may partake to the
clustering process.


title: On the reliability of mass-loss-rate estimates for AGB stars

abstract:
  In the recent literature there has been some doubt as to the reliability of
CO multi-transitional line observations as a mass-loss-rate estimator for AGB
stars. Mass-loss rates for 10 intermediate- to high-mass-loss-rate AGB stars
are derived using a detailed non-LTE, non-local radiative transfer code based
on the Monte-Carlo method to model the CO radio line intensities. The
circumstellar envelopes are assumed to be spherically symmetric and formed by
constant mass-loss rates. The energy balance is solved self-consistently and
the effects of dust on the radiation field and thermal balance are included. An
independent estimate of the mass-loss rate is also obtained from the
combination of dust radiative transfer modelling with a dynamical model of the
gas and dust particles. We find that the CO radio line intensities and shapes
are successfully reproduced for the majority of our objects assuming a constant
mass-loss rate. Moreover, the CO line intensities are only weakly dependent on
the adopted micro-turbulent velocity, in contrast to recent claims in the
literature. The two methods used in the present work to derive mass-loss-rates
are consistent within a factor of ~3 for intermediate- to high-mass-loss-rate
objects, indicating that this is a lower limit to the uncertainty in present
mass-loss-rate estimates. We find a tentative trend with chemistry. Mass-loss
rates from the dust/dynamical model are systematically higher than those from
the CO model for the carbon stars and vice versa for the M-type stars. This
could be ascribed to a discrepancy in the adopted CO/H_2-abundance ratio, but
we caution that the sample is small and systematic errors cannot be excluded.


title:
On the existence of Kundt's metrics with compact sections of null
  hypersurfaces

abstract:
  It is shown that Kundt's metric for vacuum cannot be constructed when
two-dimensional space-like sections of null hypersurfaces are compact,
connected manifolds with no boundary unless they are tori or spheres, i.e.
higher genus $\mathbf{g} \geq 2$ is excluded by vacuum Einstein equations. The
so-called {\em basic equation} (resulting from Einstein equations) is examined.
This is a non-linear PDE for unknown covector field and unknown Riemannian
structure on the two-dimensional manifold. It implies several important results
derived in this paper. It arises not only for Kundt's class but also for
degenerate Killing horizons and vacuum degenerate isolated horizons.


title: Cluster Development and Knowledge Exchange in Supply Chain

abstract:
  Industry cluster and supply chain are in focus of every countries which rely
on knowledge-based economy. Both focus on improving the competitiveness of firm
in the industry in the different aspect. This paper tries to illustrate how the
industry cluster can increase the supply chain performance. Then, the proposed
methodology concentrates on the collaboration and knowledge exchange in supply
chain. For improving the capability of the proposed methodology, information
technology is applied to facilitate the communication and the exchange of
knowledge between the actors of the supply chain within the cluster. The supply
chain of French stool producer was used as a case study to validate the
methodology and to demonstrate the result of the study.


title:
A Statistical Analysis of the "Internal Linear Combination" Method in
  Problems of Signal Separation as in CMB Observations

abstract:
  AIMS: The separation of foreground contamination from cosmic microwave
background (CMB) observations is one of the most challenging and important
problem of digital signal processing in Cosmology. In literature, various
techniques have been presented, but no general consensus about their real
performances and properties has been reached. This is due to the
characteristics of these techniques that have been studied essentially through
numerical simulations based on semi-empirical models of the CMB and the
Galactic foregrounds. Such models often have different level of sophistication
and/or are based on different physical assumptions (e.g., the number of the
Galactic components and the level of the noise). Hence, a reliable comparison
is difficult. What actually is missing is a statistical analysis of the
properties of the proposed methodologies. Here, we consider the "Internal
Linear Combination" method (ILC) which, among the separation techniques,
requires the smallest number of "a priori" assumptions. This feature is of
particular interest in the context of the CMB polarization measurements at
small angular scales where the lack of knowledge of the polarized backgrounds
represents a serious limit. METHODS: The statistical characteristics of ILC are
examined through an analytical approach and the basic conditions are fixed in a
way to work satisfactorily. RESULTS: ILC provides satisfactory results only
under rather restrictive conditions. This is a critical fact to take into
consideration in planning the future ground-based observations (e.g., with
ALMA) where, contrary to the satellite experiments, there is the possibility to
have a certain control of the experimental conditions.


title: Theory of Scalars

abstract:
  Outline: 1. Introduction, 2. Confinement, chiral dynamics and light scalar
mesons, 3. Chiral shielding of the \sigma(600), chiral constraints (the CGL
band), the \sigma(600) and the f0(980) in \pi\pi->\pi\pi, \pi\pi->KKbar,
\phi->\gamma\pi0\pi0, 4. The \phi meson radiative decays on light scalar
resonances, 5. Light scalars in \gamma\gamma collisions.
  Evidence for four-quark components of light scalars is given. The priority of
Quantum Field Theory in revealing the light scalar mystery is emphasized.


title:
Computational study of (111) epitaxially strained ferroelectric
  perovskites BaTiO3 and PbTiO3

abstract:
  The phase transition behaviour of PbTiO3 and BaTiO3 under (111) epitaxial
strain is investigated using density-functional theory calculations. From
tensile strains of +0.015 to compressive strains of -0.015, PbTiO3 undergoes
phase transitions from C2 through two Cm phases and then to R3m. The total
polarisation is found to be almost independent of strain. For the same range of
strains BaTiO3 undergoes phase transitions from a single Cm phase, through R3m
and then to R-3m. In this case the application of compressive strain inhibits
and then completely suppresses the polarisation on transition to the non-polar
R-3m phase.


title: Nuclear like effects in proton-proton collisions at high energy

abstract:
  We show that several effects considered nuclear effects are not nuclear in
the sense that they do not only occur in nucleus-nucleus and hadron-nucleus
collisions but, as well, they are present in hadron-hadron (proton-proton)
collisions. The matter creation mechanism in hh, hA and AA collisions is always
the same. The pT suppression of particles produced in large multiplicity events
compared to low multiplicity events, the elliptic flow and the Cronin effect
are predicted to occur in pp collisions at LHC energies as a consequence of the
obtained high density partonic medium.


title: Tromino Tiling Deficient Cubes of Any Side Length

abstract:
  We show that three dimensional cubes of any size can be tiled with trominoes
and, when necessary, one or two singletons in any positions. Cubes of side
length a multiple of three can always be tiled with trominoes (known), cubes of
side length congruent to 1 mod 3 can always be tiled with an arbitrary single
cube and trominoes, and cubes of side length congruent to 2 mod 3 can always be
tiled with two single cubes in arbitrary locations and trominoes.


title: On the definition of L2-Betti numbers of equivalence relations

abstract:
  We show that the L2-Betti numbers of equivalence relations defined by R.
Sauer coincide with those defined by D. Gaboriau.


title: An Ontology-based Knowledge Management System for Industry Clusters

abstract:
  Knowledge-based economy forces companies in the nation to group together as a
cluster in order to maintain their competitiveness in the world market. The
cluster development relies on two key success factors which are knowledge
sharing and collaboration between the actors in the cluster. Thus, our study
tries to propose knowledge management system to support knowledge management
activities within the cluster. To achieve the objectives of this study,
ontology takes a very important role in knowledge management process in various
ways; such as building reusable and faster knowledge-bases, better way for
representing the knowledge explicitly. However, creating and representing
ontology create difficulties to organization due to the ambiguity and
unstructured of source of knowledge. Therefore, the objectives of this paper
are to propose the methodology to create and represent ontology for the
organization development by using knowledge engineering approach. The
handicraft cluster in Thailand is used as a case study to illustrate our
proposed methodology.


title: Fano effect in a Josephson junction with a quantum dot

abstract:
  We theoretically investigate the Fano effect in dc Josephson current at the
absolute zero of temperature. The system under consideration is a double-path
Josephson junction in which one path is through an insulating barrier and the
other one is through a quantum dot (QD). Here the Kondo temperature is assumed
to be much smaller than the superconducting gap, and the Coulomb interaction
inside the QD is treated by the Hartree-Fock approximation. It is shown that
the Josephson critical current exhibits an asymmetric resonance against the QD
energy level. This behavior is caused by the interference between the two
tunneling processes between the superconductors; the direct tunneling across
the insulating barrier and the resonant one through the QD. Moreover, we find
that the Josephson critical current changes its sign around the resonance when
the Coulomb interaction is sufficiently strong. Our results suggest that
0-$\pi$ transition is induced by the cooperation of the Fano effect and the
Coulomb interaction inside the QD.


title: Some Comments on the Tests of General Relativity

abstract:
  A brief outline of the history of the discrepancies within Newtonian
mechanics at the end of the nineteenth century is given. The framework of
general relativity is described briefly and the famous 'tests' of general
relativity are considered and alternative solutions discussed, with particular
attention concentrating on the advance of the perihelion of the planet Mercury.
The implications for the claims of relativity are discussed, all with reference
to both pre and post 1915 publications.


title:
Simulation study of fast ion instability in the ILC damping ring and
  PETRA III

abstract:
  The fast ion instability is simulated in different gas pressures and fill
patterns for the damping ring of the International Linear Collider (ILC) and
PETRA III respectively. Beam size variation due to beta function and dispersion
function change is taken into account. Feedback is also applied in the
simulation.


title: Averaging Results with Theoretical Uncertainties

abstract:
  Combining measurements which have "theoretical uncertainties" is a delicate
matter, due to an unclear statistical basis. We present an algorithm based on
the notion that a theoretical uncertainty represents an estimate of bias.


title:
Probing the dusty environment of the Seyfert 1 nucleus in NGC 3783 with
  MIDI/VLTI interferometry

abstract:
  We present mid-IR spectro-interferometry of the Seyfert type 1 nucleus of NGC
3783. The dusty circumnuclear environment is spatially resolved and the
wavelength dependence of the compact emission is discussed. The observations
were carried out with the MIDI instrument at the Very Large Telescope
Interferometer in the N-band. Spectra and visibilities were derived with a
spectral resolution of 30 in the wavelength range from 8 to 13 micron. For the
interpretation we developed a simple dusty disk model with small and variable
covering factor. At baselines of 65 and 69 m, visibilities in the range of 0.4
to 0.7 were measured. The N-band spectra show a monotonic increase of the
measured flux with wavelength with no apparent silicate feature around 10
micron. We find that the mid-IR emission from the nucleus can be reproduced by
an extended dust disk or torus with a small covering factor of the radiating
dust clouds. Our mid-IR observations of NGC 3783 are consistent with a clumpy
circumnuclear dust environment. The interpretation in terms of a dusty torus
with low covering factor supports a clumpy version of the unified scheme for
AGN. The inferred sizes and luminosities are in good agreement with dust
reverberation sizes and bolometric luminosities from optical and X-ray
observations.


title: Critical Fields and Anisotropy of NdO0.82F0.18FeAs Single Crystals

abstract:
  The newly discovered iron-based superconductors have stimulated enormous
interests in the field of superconductivity. Since the new superconductor is a
layered system, the anisotropy is a parameter with the first priority to know.
Meanwhile any relevant message about the critical fields (upper critical field
and irreversibility line) are essentially important. By using flux method, we
have successfully grown the single crystals NdO0.82F0.18FeAs at ambient
pressure. Resistive measurements reveal a surprising discovery that the
anisotropy \Gamma = (mc/mab)^{1/2} is below 5, which is much smaller than the
theoretically calculated results. The data measured up to 400 K show a
continuing curved feature which prevents a conjectured linear behavior for an
unconventional metal. The upper critical fields determined based on the
Werthamer-Helfand-Hohenberg formula are H_{c2}^{H||ab}(T=0 K) = 304 T and
H_{c2}^{H||c}(T=0 K)=62-70 T, indicating a very encouraging application of the
new superconductors.


title: Thresholding Projection Estimators in Functional Linear Models

abstract:
  We consider the problem of estimating the regression function in functional
linear regression models by proposing a new type of projection estimators which
combine dimension reduction and thresholding. The introduction of a threshold
rule allows to get consistency under broad assumptions as well as minimax rates
of convergence under additional regularity hypotheses. We also consider the
particular case of Sobolev spaces generated by the trigonometric basis which
permits to get easily mean squared error of prediction as well as estimators of
the derivatives of the regression function. We prove these estimators are
minimax and rates of convergence are given for some particular cases.


title:
Effect of the Bloch-Siegert Shift on the Frequency Responses of Rabi
  Oscillations in the Case of Nutation Resonance

abstract:
  The dynamics of a two-level spin system dressed by bichromatic radiation is
studied under the conditions of double resonance when the frequency of one
(microwave) field is equal to the Larmor frequency of the spin system and the
frequency of the other (radio-frequency) field \omega_{rf} is close to the Rabi
frequency \omega_{1} in a micro-wave field. It is shown theoretically that Rabi
oscillations between dressed-spin states with the frequency \epsilon are
accompanied by higher-frequency oscillations at frequencies n\omega_{rf} and
n\omega_{rf}\pm \epsilon, where n = 1, 2, .... The most intense among these are
the signals corresponding to n = 1. The counter-rotating (antiresonance)
components of the RF field give rise to a shift of the dressed-state energy,
i.e., to a frequency shift similar to the Bloch-Siegert shift. In particular,
this shift is manifested as the dependence of the Rabi-oscillation frequency
\epsilon on the sign of the detuning \omega{1} -\omega{rf} from resonance. In
the case of double resonance, the oscillation amplitude is asymmetric; i.e.,
the amplitude at the sum frequency \omega_{rf} +\epsilon increases, while the
amplitude at the difference frequency \omega_{rf} -\epsilon decreases. The
predicted effects are confirmed by observations of the nutation signals of the
electron paramagnetic resonance (EPR) of centers in quartz and should be taken
into account to realize qubits with a low Rabi frequency in solids.


title:
Sincere-Strategy Preference-Based Approval Voting Fully Resists
  Constructive Control and Broadly Resists Destructive Control

abstract:
  We study sincere-strategy preference-based approval voting (SP-AV), a system
proposed by Brams and Sanver [Electoral Studies, 25(2):287-305, 2006], and here
adjusted so as to coerce admissibility of the votes (rather than excluding
inadmissible votes a priori), with respect to procedural control. In such
control scenarios, an external agent seeks to change the outcome of an election
via actions such as adding/deleting/partitioning either candidates or voters.
SP-AV combines the voters' preference rankings with their approvals of
candidates, where in elections with at least two candidates the voters'
approval strategies are adjusted--if needed--to approve of their most-preferred
candidate and to disapprove of their least-preferred candidate. This rule
coerces admissibility of the votes even in the presence of control actions, and
hybridizes, in effect, approval with pluralitiy voting.
  We prove that this system is computationally resistant (i.e., the
corresponding control problems are NP-hard) to 19 out of 22 types of
constructive and destructive control. Thus, SP-AV has more resistances to
control than is currently known for any other natural voting system with a
polynomial-time winner problem. In particular, SP-AV is (after Copeland voting,
see Faliszewski et al. [AAIM-2008, Springer LNCS 5034, pp. 165-176, 2008]) the
second natural voting system with an easy winner-determination procedure that
is known to have full resistance to constructive control, and unlike Copeland
voting it in addition displays broad resistance to destructive control.


title: Cosmic strings in a space-time with positive cosmological constant

abstract:
  We study Abelian strings in a fixed de Sitter background. We find that the
gauge and Higgs fields extend smoothly across the cosmological horizon and that
the string solutions have oscillating scalar fields outside the cosmological
horizon for all currently accepted values of the cosmological constant. If the
gauge to Higgs boson mass ratio is small enough, the gauge field function has a
power-like behaviour, while it is oscillating outside the cosmological horizon
if Higgs and gauge boson mass are comparable. Moreover, we observe that Abelian
strings exist only up to a maximal value of the cosmological constant and that
two branches of solutions exist that meet at this maximal value. We also
construct radially excited solutions that only exist for non-vanishing values
of the cosmological constant and are thus a novel feature as compared to flat
space-time. Considering the effect of the de Sitter string on the space-time,
we observe that the deficit angle increases with increasing cosmological
constant. Lensed objects would thus be separated by a larger angle as compared
to asymptotically flat space-time.


title: Flexible Logic from Neuronal Dynamics

abstract:
  We present two novel methods for performing logic operations. Our methods are
based on using the time dimension for programming and data representation. The
first method is based on varying the sampling moment in time of a neuronal
action potential, and the second method is based on a neural delay system,
where the generation of the action potential is delayed by specific time
lengths, to be sampled at a fixed moment in time. Both methods are supported by
explicit examples.


title: Sarah

abstract:
  SARAH is a Mathematica package for building and analyzing supersymmetric
models. SARAH just needs the gauge structure, particle content and
superpotential to produce all information about the gauge eigenstates of a
model. Breaking of gauge symmetries and mixings of particles can easily be in a
second step and entire Lagrangian is derived automatically. Also the gauge
fixing terms are derived by SARAH in R_Xi gauge, and the corresponding ghost
interactions are calculated. Using this information, SARAH can calculate the
all mass matrices, tadpole equations and vertices at tree-level for the given
model. In addition, the expressions for the 1- and 2-loop renormalization group
equations of all parameters can be calculated and an automatic calculation for
the 1-loop corrections to self energies and the tadpoles are possible.
  SARAH can write all information about the model to LaTeX files, or create a
model files for FeynArts/FormCalc, WHIZARD/OMEGA and CalcHep/CompHep, which can
also be used for dark matter studies using MicrOmegas, and in the UFO format
which is supported by MadGraph 5. Beginning with version 3, SARAH is also the
first available spectrum-generator-generator: based on the derived, analytical
expression it creates source code for SPheno to calculate the mass spectrum as
well the SUSY decays with high precision. In that way, it is possible to
implement new models in SPheno without the need to write any Fortran code by
hand. Already many models beyond the MSSM are included in the public version of
SARAH and the implementation of new models is easy and straightforward.


title:
Nonparametric Partial Importance Sampling for Financial Derivative
  Pricing

abstract:
  Importance sampling is a promising variance reduction technique for Monte
Carlo simulation based derivative pricing. Existing importance sampling methods
are based on a parametric choice of the proposal. This article proposes an
algorithm that estimates the optimal proposal nonparametrically using a
multivariate frequency polygon estimator. In contrast to parametric methods,
nonparametric estimation allows for close approximation of the optimal
proposal. Standard nonparametric importance sampling is inefficient for
high-dimensional problems. We solve this issue by applying the procedure to a
low-dimensional subspace, which is identified through principal component
analysis and the concept of the effective dimension. The mean square error
properties of the algorithm are investigated and its asymptotic optimality is
shown. Quasi-Monte Carlo is used for further improvement of the method. It is
easy to implement, particularly it does not require any analytical computation,
and it is computationally very efficient. We demonstrate through path-dependent
and multi-asset option pricing problems that the algorithm leads to significant
efficiency gains compared to other algorithms in the literature.


title: Long-range correlations in disordered graphene

abstract:
  The appearence of long-range correlations near the Dirac point of a
Dirac-like spinor model with random vector potential is studied. These
correlations originate from a spontaneously broken symmetry and their
corresponding Goldstone modes. Using a strong-disorder expansion, correlation
functions and matrix elements are analyzed and compared with results from a
weak-disorder expansion. The local density of states correlation and the
overlap between states above and below the Dirac point are characterized by a
long-range behavior. The correlation range decreases with the distance from the
Dirac point. Transport is diffusive and the diffusion coefficient is
proportional to the one-particle scattering time for any strength of disorder.
A consequence of the special properties of particle-hole scattering is a
constant microwave conductivity for weak as well as for strong disorder,
describing a deviation from conventional Drude-like transport. Some properties
of the model can be linked to a kind of Kondo scale, which is generated by
disorder. Finally, the properties of the wave functions at the Dirac point are
characterized by their participation ratios, indicating a critical state at the
Dirac point.


title: Asymptotic Harmonic Analysis on the Space of Square Complex Matrices

abstract:
  In this paper, we determine the spherical functions of positive type on the
inductive limit space of square complex matrices.


title: Some special functions identities arising from commuting operators

abstract:
  Commuting is an important property in many cases of investigation of
properties of operators as well as in various applications, especially in
quantum physics. Using the observation that the generalized weighted
differential operator of order $k$ and the weighted Hardy-type operator commute
we derive a number of new and interesting identities involving some functions
of mathematical physics.


title:
Tethered Monte Carlo: computing the effective potential without critical
  slowing down

abstract:
  We present Tethered Monte Carlo, a simple, general purpose method of
computing the effective potential of the order parameter (Helmholtz free
energy). This formalism is based on a new statistical ensemble, closely related
to the micromagnetic one, but with an extended configuration space (through
Creutz-like demons). Canonical averages for arbitrary values of the external
magnetic field are computed without additional simulations. The method is put
to work in the two dimensional Ising model, where the existence of exact
results enables us to perform high precision checks. A rather peculiar feature
of our implementation, which employs a local Metropolis algorithm, is the total
absence, within errors, of critical slowing down for magnetic observables.
Indeed, high accuracy results are presented for lattices as large as L=1024.


title: Symmetric space sigma-model dynamics: Current formalism

abstract:
  After explicitly constructing the symmetric space sigma model lagrangian in
terms of the coset scalars of the solvable Lie algebra gauge in the current
formalism we derive the field equations of the theory.


title: Science results from the imaging Fourier transform spectrometer SpIOMM

abstract:
  SpIOMM is an imaging Fourier transform spectrometer designed to obtain the
visible range (350 to 850 nm) spectrum of every light source in a circular
field of view of 12 arcminutes in diameter. It is attached to the 1.6-m
telescope of the Observatoire du Mont Megantic in southern Quebec. We present
here some results of three successful observing runs in 2007, which highlight
SpIOMMs capabilities to map emission line objects over a very wide field of
view and a broad spectral range. In particular, we discuss data cubes from the
planetary nebula M27, the supernova remnants NGC 6992 and M1, the barred spiral
galaxy NGC7479, as well as Stephans quintet, an interacting group of galaxies.


title: The Radial Velocity Experiment (RAVE): second data release

abstract:
  We present the second data release of the Radial Velocity Experiment (RAVE),
an ambitious spectroscopic survey to measure radial velocities (RVs) and
stellar atmosphere parameters of up to one million stars using the 6dF
multi-object spectrograph on the 1.2-m UK Schmidt Telescope of the
Anglo-Australian Observatory (AAO). It is obtaining medium resolution spectra
(median R=7,500) in the Ca-triplet region (8,410--8,795 \AA) for southern
hemisphere stars in the magnitude range 9<I<12. Following the first data
release (Steinmetz et al. 2006) the current release doubles the sample of
published RVs, now containing 51,829 RVs for 49,327 individual stars observed
on 141 nights between April 11 2003 and March 31 2005. Comparison with external
data sets shows that the new data collected since April 3 2004 show a standard
deviation of 1.3 km/s, about twice better than for the first data release. For
the first time this data release contains values of stellar parameters from
22,407 spectra of 21,121 individual stars. They were derived by a penalized
\chi^2 method using an extensive grid of synthetic spectra calculated from the
latest version of Kurucz models. From comparison with external data sets, our
conservative estimates of errors of the stellar parameters (for a spectrum with
S/N=40) are 400 K in temperature, 0.5 dex in gravity, and 0.2 dex in
metallicity. We note however that the internal errors estimated from repeat
RAVE observations of 822 stars are at least a factor 2 smaller. We demonstrate
that the results show no systematic offsets if compared to values derived from
photometry or complementary spectroscopic analyses. The data release includes
proper motion and photometric measurements. It can be accessed via the RAVE
webpage: http://www.rave-survey.org and through CDS.


title: Coulomb blockade for an oscillating tunnel junction

abstract:
  We consider a tunnel junction formed between a fixed electrode and an
oscillating one. Accumulation of the charge on the junction capacitor induces a
force on the nano-mechanical oscillator. The junction is voltage biased and
connected in series with an impedance $Z(\omega)$. We discuss how the picture
of Coulomb blockade is modified by the presence of the oscillator. Quantum
fluctuations of the mechanical oscillator modify the $I$-$V$ characteristics
particularly in the strong Coulomb blockade limit. We show that the oscillator
can be taken into account by a simple modification of the effective impedance
of the circuit. We discuss in some details the case of a single inductance
$Z(\omega)=iL\omega$ and of a constant resistance $Z(\omega)=R$. With little
modifications the theory applies also to incoherent transport in Josephson
junctions in the tunneling limit.


title: Impurity Induced Polar Kerr Effect in A Chiral p-wave Superconductor

abstract:
  We discuss the polar Kerr effect (PKE) in a chiral p-wave (p_x+i p_y-wave)
superconductor. It is found that the off-diagonal component of a
current-current correlation function is induced by impurity scattering in the
chiral p-wave condensate, and a nonzero Hall conductivity is obtained using the
Kubo formula. We estimate the Kerr rotation angle by using this
impurity-induced Hall conductivity and compare it with experimental results
[Jing Xia et al., Phys. Rev. Lett. 97, 167002 (2006)].


title: Paramagnetic adsorbates on graphene: a charge transfer analysis

abstract:
  We introduce a modified version of the Hirshfeld charge analysis method and
demonstrate its accurateness by calculating the charge transfer between the
paramagnetic molecule NO2 and graphene. The charge transfer between
paramagnetic molecules and a graphene layer as calculated with ab initio
methods can crucially depend on the size of the supercell used in the
calculation. This has important consequences for adsorption studies involving
paramagnetic molecules such as NO2 physisorbed on graphene or on carbon
nanotubes.


title:
On the geometry of classically integrable two-dimensional non-linear
  sigma models

abstract:
  A master equation expressing the classical integrability of two-dimensional
non-linear sigma models is found. The geometrical properties of this equation
are outlined. In particular, a closer connection between integrability and
T-duality transformations is emphasised. Finally, a whole new class of
integrable non-linear sigma models is found and all their corresponding Lax
pairs depend on a spectral parameter.


title: Dualisation of the principal sigma model

abstract:
  The first-order formulation of the principal sigma model with a Lie group
target space is performed. By using the dualisation of the algebra and the
field content of the theory the field equations which are solely written in
terms of the field strengths are realized through an extended symmetry algebra
parametrization. The structure of this symmetry algebra is derived so that it
generates the realization of the field equations in a Bianchi identity of the
current derived from the extended parametrization.


title: Nuclear isospin mixing and elastic parity-violating electron scattering

abstract:
  The influence of nuclear isospin mixing on parity-violating elastic electron
scattering is studied for the even-even, N=Z nuclei 12C, 24Mg, 28Si, and 32S.
Their ground-state wave functions have been obtained using a self-consistent
axially-symmetric mean-field approximation with density-dependent effective
two-body Skyrme interactions. Some differences from previous shell-model
calculations appear for the isovector Coulomb form factors which play a role in
determining the parity-violating asymmetry. To gain an understanding of how
these differences arise, the results have been expanded in a spherical harmonic
oscillator basis. Results are obtained not only within the plane-wave Born
approximation, but also using the distorted-wave Born approximation for
comparison with potential future experimental studies of parity-violating
electron scattering. To this end, for each nucleus the focus is placed on
kinematic ranges where the signal (isospin-mixing effects on the
parity-violating asymmetry) and the experimental figure-of-merit are maximized.
Strangeness contributions to the asymmetry are also briefly discussed, since
they and the isospin mixing contributions may play comparable roles for the
nuclei being studied at the low momentum transfers of interest in the present
work.


title: Thermodynamics of two lattice ice models in three dimensions

abstract:
  In a recent paper we introduced two Potts-like models in three dimensions,
which share the following properties: (A) One of the ice rules is always
fulfilled (in particular also at infinite temperature). (B) Both ice rules hold
for groundstate configurations. This allowed for an efficient calculation of
the residual entropy of ice I (ordinary ice) by means of multicanonical
simulations. Here we present the thermodynamics of these models. Despite their
similarities with Potts models, no sign of a disorder-order phase transition is
found.


title: Altitude-dependent polarization in radio pulsars

abstract:
  Because of the corotation, the polarization angle (PA) curve of a pulsar lags
the intensity profile by 4r/Rlc rad in pulse phase. I present a simple and
short derivation of this delay-radius relation to show that it is not caused by
the aberration (understood as the normal beaming effect) but purely by
contribution of corotation to the electron acceleration in the observer's
frame. Available altitude-dependent formulae for the PA curve are expressed
through observables and emission altitude to make them immediately ready to use
in radio data modelling. The analytical approximations for the
altitude-dependent PA curve are compared with exact numerical results to show
how they perform at large emission altitudes. I also discuss several possible
explanations for the opposite-than-normal shift of PA curve, exhibited by the
pedestal emission of B1929+10 and B0950+08.


title: Integrated field equations of heterotic supergravities

abstract:
  The first-order bosonic field equations of the D-dimensional effective low
energy theory which describes the massless background coupling of the
D-dimensional fully Higgsed heterotic string are derived.


title:
A study on the anomaly of $p$ over $\pi$ ratios in $Au+Au$ collisions
  with jet quenching

abstract:
  The ratios of $p/\pi$ at large transverse momentum in central $Au+Au$
collisions at RHIC are studied in the framework of jet quenching based on a
next-to-leading order pQCD parton model. It is shown that theoretical
calculations with a gluon energy loss larger than the quark energy loss will
naturally lead to a smaller $p/\pi$ ratios at large transverse momentum in
$Au+Au$ collisions than those in $p+p$ collisions at the same energy. Scenarios
with equal energy losses for gluons and quarks and a strong jet conversion are
both explored and it is demonstrated in both scenarios $p/\pi$ ratios at high
$p_T$ in central $Au+Au$ collisions are enhanced and the calculated ratios of
protons over pions approach to the experimental measurements. However, ${\bar
p}/p$ in the latter scenario is found to fit data better than that in the
former scenario.


title: An efficient and provably secure arbitrated quantum signature scheme

abstract:
  In this paper, an efficient arbitrated quantum signature scheme is proposed
by combining quantum cryptographic techniques and some ideas in classical
cryptography. In the presented scheme, the signatory and the receiver can share
a long-term secret key with the arbitrator by utilizing the key together with a
random number. While in previous quantum signature schemes, the key shared
between the signatory and the arbitrator or between the receiver and the
arbitrator could be used only once, and thus each time when a signatory needs
to sign, the signatory and the receiver have to obtain a new key shared with
the arbitrator through a quantum key distribution protocol. Detailed
theoretical analysis shows that the proposed scheme is efficient and provably
secure.


title: Matrix Models, Gauge Theory and Emergent Geometry

abstract:
  We present, theoretical predictions and Monte Carlo simulations, for a simple
three matrix model that exhibits an exotic phase transition. The nature of the
transition is very different if approached from the high or low temperature
side. The high temperature phase is described by three self interacting random
matrices with no background spacetime geometry. As the system cools there is a
phase transition in which a classical two-sphere condenses to form the
background geometry. The transition has an entropy jump or latent heat, yet the
specific heat diverges as the transition is approached from low temperatures.
We find no divergence or evidence of critical fluctuations when the transition
is approached from the high temperature phase. At sufficiently low temperatures
the system is described by small fluctuations, on a background classical
two-sphere, of a U(1) gauge field coupled to a massive scalar field. The
critical temperature is pushed upwards as the scalar field mass is increased.
Once the geometrical phase is well established the specific heat takes the
value 1 with the gauge and scalar fields each contributing 1/2.


title: Gauge theory picture of an ordering transition in a dimer model

abstract:
  We study a phase transition in a 3D lattice gauge theory, a "coarse-grained"
version of a classical dimer model. Duality arguments indicate that the dimer
lattice theory should be dual to a XY model coupled to a gauge field with
geometric frustration. The transition between a Coulomb phase with dipolar
correlations and a long range ordered columnar phase is understood in terms of
a Higgs mechanism. Monte Carlo simulations of the dual model indicate a
continuous transition with exponents close but apparently different from those
of the 3d XY model. The continuous nature of the transition is confirmed by a
flowgram analysis.


title: Beyond XSPEC: Towards Highly Configurable Analysis

abstract:
  We present a quantitative comparison between software features of the defacto
standard X-ray spectral analysis tool, XSPEC, and ISIS, the Interactive
Spectral Interpretation System. Our emphasis is on customized analysis, with
ISIS offered as a strong example of configurable software. While noting that
XSPEC has been of immense value to astronomers, and that its scientific core is
moderately extensible--most commonly via the inclusion of user contributed
"local models"--we identify a series of limitations with its use beyond
conventional spectral modeling. We argue that from the viewpoint of the
astronomical user, the XSPEC internal structure presents a Black Box Problem,
with many of its important features hidden from the top-level interface, thus
discouraging user customization. Drawing from examples in custom modeling,
numerical analysis, parallel computation, visualization, data management, and
automated code generation, we show how a numerically scriptable, modular, and
extensible analysis platform such as ISIS facilitates many forms of advanced
astrophysical inquiry.


title:
Prediction of residual stress due to early age behaviour of massive
  concrete structures: on site experiments and macroscopic modelling

abstract:
  Early age behaviour of concrete is based on complex multi-physical and
multiscale phenomena. The predication of both cracking risk and residual
stresses in hardened concrete structures is still a challenging task. We
propose in this paper a practical method to characterize in the construction
site the material parameters and to identify a macroscopic model from simple
tests. We propose for instance to use a restrained shrinkage ring test to
identify a basic early age creep model based on a simple ageing visco-elastic
Kelvin model. The strain data obtained from this test can be treated through an
early age finite element incremental procedure such that the fitting parameters
of the creep law can be quickly identified. The others properties of concrete
have been measured at different ages (elastic properties, hydration kinetics,
and coefficient of thermal expansion). From the identified early age model, we
computed the temperature rise and the stress development in a non reinforced
concrete stress for nuclear waste. The good agreement between in-situ
measurement and predicted behaviour allowed us to validate our approach.


title:
Universal Coding on Infinite Alphabets: Exponentially Decreasing
  Envelopes

abstract:
  This paper deals with the problem of universal lossless coding on a countable
infinite alphabet. It focuses on some classes of sources defined by an envelope
condition on the marginal distribution, namely exponentially decreasing
envelope classes with exponent $\alpha$. The minimax redundancy of
exponentially decreasing envelope classes is proved to be equivalent to
$\frac{1}{4 \alpha \log e} \log^2 n$. Then a coding strategy is proposed, with
a Bayes redundancy equivalent to the maximin redundancy. At last, an adaptive
algorithm is provided, whose redundancy is equivalent to the minimax redundancy


title: Local detection of X-ray spectroscopies with an in-situ AFM

abstract:
  The in situ combination of Scanning Probe Microscopies (SPM) with X-ray
microbeams adds a variety of new possibilities to the panoply of synchrotron
radiation techniques. In this paper we describe an optics-free AFM/STM that can
be directly installed on synchrotron radiation end stations for such combined
experiments. The instrument can be used just for AFM imaging of the
investigated sample or can be used for detection of photoemitted electrons with
a sharp STM-like tip, thus leading to the local measure of the X-ray absorption
signal. Alternatively one can can measure the flux of photon impinging on the
sharpest part of the tip to locally map the pattern of beams diffracted from
the sample. In this paper we eventually provide some examples of local
detection of XAS and diffraction.


title: Growth of a dynamical correlation length in an aging superspin glass

abstract:
  We report on zero field cooled magnetization relaxation experiments on a
concen- trated frozen ferrofluid exhibiting a low temperature superspin glass
transition. With a method initially developed for spin glasses, we investigate
the field dependence of the relaxations that take place after different aging
times. We extract the typical number of correlated spins involved in the aging
dynamics. This brings important insights into the dynamical correlation length
and its time growth. Our results, consistent with expressions obtained for spin
glasses, extend the generality of these behaviours to the class of superspin
glasses. Since the typical flipping time is much larger for superspins than for
atomic spins, our experiments probe a time regime much closer to that of
numerical simulations.


title:
Star-forming galaxies in low-redshift clusters: Data and integrated
  galaxy properties

abstract:
  This paper is a continuation of an ongoing study of the evolutionary
processes affecting cluster galaxies. Both CCD R band and H alpha narrow-band
imaging was used to determine photometric parameters (m_(r), r_(24), H alpha
flux and equivalent width) and derive star formation rates for 227 CGCG
galaxies in 8 low-redshift clusters. The galaxy sample is a subset of CGCG
galaxies in an objective prism survey of cluster galaxies for H alpha emission.
It is found that detection of emission-line galaxies in the OPS is 85%, 70%,
and 50% complete at the mean surface brightness values of 1.25 x 10^(-19), 5.19
x 10^(-20), and 1.76 x 10^(-20) W m^(-2) arcsec^(-2), respectively, measured
within the R band isophote of 24 mag arcsec^(-2) for the galaxy. The CCD data,
together with matched data from a recent H alpha galaxy survey of UGC galaxies
within 3000 km s^(-1), will be used for a comparative study of R band and H
alpha surface photometry between cluster and field spirals.


title: Finite Generation of Algebras Associated to Powers of Ideals

abstract:
  We study generalized symbolic powers and form ideals of powers of ideals and
compare their growth with the growth of ordinary powers, and we discuss the
question of when the graded rings attached to symbolic powers or to form ideals
of powers are finitely generated.


title: HST observations of gravitationally lensed QSOs

abstract:
  Thanks to its sharp view, HST has significantly improved our knowledge of
tens of gravitationally lensed quasars in four different respects: (1)
confirming their lensed nature; (2) detecting the lensing galaxy responsible
for the image splitting; (3) improving the astrometric accuracy on the
positions of the unresolved QSO images and of the lens; (4) resolving extended
lensed structures from the QSO hosts into faint NIR or optical rings or arcs.
These observations have helped to break some degeneracies on the lens
potential, to probe the galaxy evolution and to reconstruct the true shape of
the QSO host with an increased angular resolution.


title: Kaon Decays from AdS/QCD

abstract:
  We briefly review one of the current applications of the AdS/CFT
correspondence known as AdS/QCD and discuss about the calculation of four-point
quark-flavour current correlation functions and their applications to the
calculation of observables related to neutral kaon decays and neutral kaon
mixing processes.


title: Tensor-triangulated categories and dualities

abstract:
  In a triangulated symmetric monoidal closed category, there are natural
dualities induced by the internal Hom. Given a monoidal functor f^* between two
such catgories and adjoint couples (f^*,f_*) and (f_*,f^!), we prove the
necessary commutative diagrams for f^* and f_* to respect certain dualities,
for a projection formula to hold between them (as duality preserving functors)
and for classical base change and composition formulas to hold when such
duality preserving functors are composed. This framework is for example useful
to define push-forwards for Witt groups.


title:
Mass distribution and orbital anisotropy of early-type galaxies:
  constraints from the Mass Plane

abstract:
  Massive early-type galaxies are observed to lie on the Mass Plane (MP), a
two-dimensional manifold in the space of effective radius R_e, projected mass
M_p (measured via strong gravitational lensing) and projected velocity
dispersion sigma within R_e/2. The MP is less `tilted' than the Fundamental
Plane, and the two have comparable associated scatter. This means that
c_e2=2*G*M_p/(R_e*sigma^2) is a nearly universal constant in the range
sigma=175-400 km/s. This finding can be used to constrain the mass distribution
and internal dynamics of early-type galaxies. We find that a relatively wide
class of spherical galaxy models has values of c_e2 in the observed range,
because c_e2 is not very strongly sensitive to the mass distribution and
orbital anisotropy. If the total mass distribution is isothermal, a broad range
of stellar luminosity profile and anisotropy is consistent with the
observations, while NFW dark-matter halos require more fine tuning of the
stellar mass fraction, luminosity profile and anisotropy. If future data can
cover a broader range of masses, the MP could be seen to be tilted and the
value of any such tilt would provide a discriminant between models for the
total mass-density profile of the galaxies. [Abridged]


title: Push-forwards for Witt groups of schemes

abstract:
  We define push-forwards for Witt groups of schemes along proper morphisms,
using Grothendieck duality theory. This article is an application of results of
the authors on tensor-triangulated closed categories to such structures on some
derived categories of schemes together with classical derived functors.


title: PGMS: to study the Galactic magnetism out of the Galactic plane

abstract:
  The Parkes Galactic Meridian Survey (PGMS) is a 5 deg X 90 deg strip to map
the polarized synchrotron emission along a Galactic meridian from the Galactic
plane down to the south Galactic pole. The survey is carried out at the Parkes
radio telescope at a frequency of 2.3 GHz with 30 adjacent 8-MHz bands which
enable Faraday Rotation studies. The scientific goal is twofold: (1) To probe
the Galactic magnetism off the Galactic plane of which little is known so far.
PGMS gives an insight into the Galactic magnetic field in the thick disc, halo,
and disc-halo transition; (2) To study the synchrotron emission as foreground
noise of the CMB Polarization, especially for the weak B-Mode which carries the
signature of the primordial gravitational wave background left by the
Inflation. PGMS observations have been recently concluded. In this contribution
we present the survey along with first results.


title: Skyrme and Wigner crystals in graphene

abstract:
  At low-energy, the band structure of graphene can be approximated by two
degenerate valleys $(K,K^{\prime})$ about which the electronic spectra of the
valence and conduction bands have linear dispersion relations. An electronic
state in this band spectrum is a linear superposition of states from the $A$
and $B$ sublattices of the honeycomb lattice of graphene. In a quantizing
magnetic field, the band spectrum is split into Landau levels with level N=0
having zero weight on the $B(A)$ sublattice for the $% K(K^{\prime})$ valley.
Treating the valley index as a pseudospin and assuming the real spins to be
fully polarized, we compute the energy of Wigner and Skyrme crystals in the
Hartree-Fock approximation. We show that Skyrme crystals have lower energy than
Wigner crystals \textit{i.e.} crystals with no pseudospin texture in some range
of filling factor $\nu $ around integer fillings. The collective mode spectrum
of the valley-skyrmion crystal has three linearly-dispersing Goldstone modes in
addition to the usual phonon mode while a Wigner crystal has only one extra
Goldstone mode with a quadratic dispersion. We comment on how these modes
should be affected by disorder and how, in principle, a microwave absorption
experiment could distinguish between Wigner and Skyrme crystals.


title:
Exact distorted-wave approach to multiple-scattering theory for general
  potentials

abstract:
  We present a new approach to real-space multiple-scattering theory for
molecules and clusters, based on the two-potential (distorted-wave)
Lippmann-Schwinger equation formalism. Our approach uses a recently developed
form [D. L. Foulis, Phys. Rev. A70, 022706 (2004)], for the partial-wave
expansions of the exact time-independent single-particle Green function for a
general potential, to solve exactly the scattering problem for the distorting
potential. The multiple-scattering problem for the full multicenter molecular
potential is then developed along familiar lines, within a partition of space
consisting of non-overlapping atomic spheres, but relative to the distorting
potential. To achieve this some new general Green-function re-expansion
formulas are derived, as well as further developments of our earlier
partial-wave expansions. Based on the division of the multicenter molecular
potential into the non-singular distorting potential and a remaining singular
part we develop explicitly the secular equations of our approach and prove a
result concerning the symmetry of the atomic matrices. The new secular
equations are similar in overall form to those of related methods, requiring
coupled radial Schr\"odinger-equation solutions for each atomic center,
together with atomic-sphere surface integrals, but no volume integrals. We
treat both continuum (scattering) states and bound states within the same
framework, and consider also the case of an outer sphere.


title: Warm-Chaplygin inflationary universe model

abstract:
  Warm inflationary universe models in the context of a Chaplygin gas equation
are studied. General conditions required for these models to be realizable are
derived and discussed. By using a chaotic potential we develop models for a
dissipation coefficient of the form $\Gamma\propto \phi^n$, with $n=0$ or
$n\neq 0$.


title: Steganographic Routing in Multi Agent System Environment

abstract:
  In this paper we present an idea of trusted communication platform for
Multi-Agent Systems (MAS) called TrustMAS. Based on analysis of routing
protocols suitable for MAS we have designed a new proactive hidden routing.
Proposed steg-agents discovery procedure, as well as further routes updates and
hidden communication, are cryptographically independent. Steganographic
exchange can cover heterogeneous and geographically outlying environments using
available cross-layer covert channels. Finally we have specified rules that
agents have to follow to benefit the TrustMAS distributed router platform.


title: Thermal Dimuon Emission in In-In at the CERN SPS

abstract:
  The NA60 experiment at the CERN SPS has studied low-mass dimuon production in
158A GeV In-In collisions. A significant excess of pairs is observed above the
yield expected from neutral meson decays, consistent with a dominant
contribution from $\pi\pi\to\rho\to\mu\mu$. This paper presents precision
results on the mass and transverse momentum spectra of the excess pairs. The
space-time averaged rho spectral function associated to the measured mass
distribution shows a significant broadening, but essentially no mass shift. The
slope parameter $T_{eff}$ extracted from the spectra rises with dimuon mass up
to the $\rho$, followed by a sudden decline above. While the initial rise is
consistent with the expectations for radial flow of a hadronic decay source,
the decline indicates a transition to an emission source with much smaller
flow, possibly of partonic origin.


title:
Semileptonic $B_{q}\to D^{\ast}_{q}l\nu $ $(q=s, d, u)$ Decays in QCD
  Sum Rules

abstract:
  The form factors relevant to $B_{q}\to D^{\ast}_{q}(J^{P}=1^{-}) ell\nu$
$(q=s, d, u)$ decays are calculated in the framework of the three point QCD sum
rules approach. The heavy quark effective theory prediction of the form factors
as well as $1/m_{b}$ corrections to those form factors are obtained. A
comparison of the results for the ratio of form factors at zero recoil limit
and other values of $q^{2}$ with the predictions of the subleading Isgur-Wise
form factor application for $B\to D^{\ast}\ell\nu$ is presented. The total
decay width and branching ratio for these decays are also evaluated using the
$q^2$ dependencies of these form factors. The results are in good agreement
with the constituent quark meson model and existing experimental data. The
$q=s$ case can also be detected at LHC in the near future.


title: Multirate Synchronous Sampling of Sparse Multiband Signals

abstract:
  Recent advances in optical systems make them ideal for undersampling
multiband signals that have high bandwidths. In this paper we propose a new
scheme for reconstructing multiband sparse signals using a small number of
sampling channels. The scheme, which we call synchronous multirate sampling
(SMRS), entails gathering samples synchronously at few different rates whose
sum is significantly lower than the Nyquist sampling rate. The signals are
reconstructed by solving a system of linear equations. We have demonstrated an
accurate and robust reconstruction of signals using a small number of sampling
channels that operate at relatively high rates. Sampling at higher rates
increases the signal to noise ratio in samples. The SMRS scheme enables a
significant reduction in the number of channels required when the sampling rate
increases. We have demonstrated, using only three sampling channels, an
accurate sampling and reconstruction of 4 real signals (8 bands). The matrices
that are used to reconstruct the signals in the SMRS scheme also have low
condition numbers. This indicates that the SMRS scheme is robust to noise in
signals. The success of the SMRS scheme relies on the assumption that the
sampled signals are sparse. As a result most of the sampled spectrum may be
unaliased in at least one of the sampling channels. This is in contrast to
multicoset sampling schemes in which an alias in one channel is equivalent to
an alias in all channels. We have demonstrated that the SMRS scheme obtains
similar performance using 3 sampling channels and a total sampling rate 8 times
the Landau rate to an implementation of a multicoset sampling scheme that uses
6 sampling channels with a total sampling rate of 13 times the Landau rate.


title: Two Impurity Anderson problem: Perturbative Kondo-Doublet interaction

abstract:
  We reobtain the Kondo-Doublet interaction by means of the Brillouin-Wigner
Perturbation theory. By applying the same method to the single impurity case we
show that the Kondo-Doublet interaction is a direct consequence of the Kondo
screening cloud. We fully confirm our previous results on this novel
interaction. In particular, we found that for values of the system parameters
typical of semiconductor Quantum Dots heterostructures, the ferromagnetic
Kondo-Doublet interaction dominates over the RKKY one.


title:
A new stellar library in the region of the CO index at 2.3 $\mu$m. New
  index definition and empirical fitting functions

abstract:
  Context: The analysis of unresolved stellar populations demands evolutionary
synthesis models with realistic physical ingredients and extended wavelength
coverage.
  Aims: To obtain a quantitative description of the first CO bandhead at 2.3
$\mu$m, to allow stellar population models to provide improved predictions in
this wavelength range.
  Methods: We have observed a new stellar library with a better coverage of the
stellar atmospheric parameter space than preceding works. We have performed a
detailed analysis of the robustness of previous CO index definitions with
spectral resolution, wavelength calibration, signal-to-noise ratio, and flux
calibration.
  Results: We define a new line-strength index for the first CO bandhead at 2.3
$\mu$m, D$_{\rm CO}$, better suited for stellar population studies than
previous index definitions. We compute empirical fitting functions for the CO
feature as a function of the stellar parameters (T$_{\rm eff}$, $\log g$ and
[Fe/H]), showing a detailed quantitative metallicity dependence.


title: Sampling Spatially Correlated Clutter

abstract:
  Correlated ${\cal G}$ distributions can be used to describe the clutter seen
in images obtained with coherent illumination, as is the case of B-scan
ultrasound, laser, sonar and synthetic aperture radar (SAR) imagery. These
distributions are derived using the square root of the generalized inverse
Gaussian distribution for the amplitude backscatter within the multiplicative
model. A two-parameters particular case of the amplitude ${\mathcal G}$
distribution, called ${\mathcal G}_{A}^{0}$, constitutes a modeling improvement
with respect to the widespread ${\mathcal K}_{A}$ distribution when fitting
urban, forested and deforested areas in remote sensing data. This article deals
with the modeling and the simulation of correlated ${\mathcal
G}_{A}^{0}$-distributed random fields. It is accomplished by means of the
Inverse Transform method, applied to Gaussian random fields with spatial
correlation. The main feature of this approach is its generality, since it
allows the introduction of negative correlation values in the resulting
process, necessary for the proper explanation of the shadowing effect in many
SAR images.


title: Analysis of the Rare $B_c \to D_{s,d}^{*} l^+ l^-$ Decays in QCD

abstract:
  The rare $B_c \to D_{s,d}^{*} l^+ l^-$ decays are investigated in the
framework of the three point QCD sum rules approach. Considering the gluon
condensate corrections to the correlation function, the form factors relevant
to these transitions are calculated. The total decay width and branching ratio
for these decays are also evaluated. The results for the branching ratios are
in good agreement with the quark models.


title: Pure Spinor Partition Function and the Massive Superstring Spectrum

abstract:
  We explicitly compute up to the fifth mass-level the partition function of
ten-dimensional pure spinor worldsheet variables including the spin dependence.
After adding the contribution from the (x^{\mu}, \theta^{\alpha}, p_{\alpha})
matter variables, we reproduce the massive superstring spectrum. Even though
pure spinor variables are bosonic, the pure spinor partition function contains
fermionic states which first appear at the second mass-level. These fermionic
states come from functions which are not globally defined in pure spinor space,
and are related to the b ghost in the pure spinor formalism. This result
clarifies the proper definition of the Hilbert space for pure spinor variables.


title: Properties of cut ideals associated to ring graphs

abstract:
  A cut ideal of a graph records the relations among the cuts of the graph.
These toric ideals have been introduced by Sturmfels and Sullivant who also
posed the problem of relating their properties to the combinatorial structure
of the graph.
  We study the cut ideals of the family of ring graphs, which includes trees
and cycles. We show that they have quadratic Gr\"obner bases and that their
coordinate rings are Koszul, Hilbertian, and Cohen-Macaulay, but not Gorenstein
in general.


title: Hilbert space of curved \beta\gamma systems on quadric cones

abstract:
  We clarify the structure of the Hilbert space of curved \beta\gamma systems
defined by a quadratic constraint. The constraint is studied using intrinsic
and BRST methods, and their partition functions are shown to agree. The quantum
BRST cohomology is non-empty only at ghost numbers 0 and 1, and there is a
one-to-one mapping between these two sectors. In the intrinsic description, the
ghost number 1 operators correspond to the ones that are not globally defined
on the constrained surface. Extension of the results to the pure spinor
superstring is discussed in a separate work.


title: Collisional stability of a three-component degenerate Fermi gas

abstract:
  We report on the creation of a degenerate Fermi gas consisting of a balanced
mixture of atoms in three different hyperfine states of $^6$Li. This new system
consists of three distinguishable Fermions with different and tunable
interparticle scattering lengths $a_{12}$, $a_{13}$ and $a_{23}$. We are able
to prepare samples containing $5 \cdot 10^4$ atoms in each state at a
temperature of about $215 $nK, which corresponds to $T/T_F \approx 0.37$. We
investigated the collisional stability of the gas for magnetic fields between 0
and 600 G and found a prominent loss feature at 130 G. From lifetime
measurements we determined three-body loss coefficients, which vary over nearly
three orders of magnitude.


title: Numerical study of the Kardar-Parisi-Zhang equation

abstract:
  We integrate numerically the Kardar-Parisi-Zhang (KPZ) equation in 1+1 and
2+1 dimensions using an Euler discretization scheme and the replacement of
${(\nabla h)}^2$ by exponentially decreasing functions of that quantity to
suppress instabilities. When applied to the equation in 1+1 dimensions, the
method of instability control provides values of scaling amplitudes consistent
with exactly known results, in contrast to the deviations generated by the
original scheme. In 2+1 dimensions, we spanned a range of the model parameters
where transients with Edwards-Wilkinson or random growth are not bserved, in
box sizes $8\leq L\leq 128$. We obtain roughness exponent $0.37\leq \alpha\leq
0.40$ and steady state height distributions with skewness $S= 0.25\pm 0.01$ and
kurtosis $Q= 0.15\pm 0.1$. These estimates are obtained after extrapolations to
the large $L$ limit, which is necessary due to significant finite-size effects
in the estimates of effective exponents and height distributions. On the other
hand, the steady state roughness distributions show weak scaling corrections
and evidence of stretched exponentials tails. These results confirm previous
estimates from lattice models, showing their reliability as representatives of
the KPZ class.


title:
Electric-field switchable magnetization via the Dzyaloshinskii-Moriya
  interaction: FeTiO_3 versus BiFeO_3

abstract:
  In this article we review and discuss a mechanism for coupling between
electric polarization and magnetization that can ultimately lead to
electric-field switchable magnetization. The basic idea is that a ferroelectric
distortion in an antiferromagnetic material can "switch on" the
Dzyaloshinskii-Moriya interaction which leads to a canting of the
antiferromagnetic sublattice magnetizations, and thus to a net magnetization.
This magnetization M is coupled to the polarization P via a trilinear free
energy contribution of the form P(M x L), where L is the antiferromagnetic
order parameter. In particular, we discuss why such an invariant is present in
R3c FeTiO_3 but not in the isostructural multiferroic BiFeO_3. Finally, we
construct symmetry groups that in general allow for this kind of
ferroelectrically-induced weak ferromagnetism.


title:
Analysis of the rare semileptonic $B_c \rar P(D,D_s)
  l^{+}l^{-}/\nu\bar{\nu}$ decays within QCD sum rules

abstract:
  Considering the gluon condensate corrections, the form factors relevant to
the semileptonic rare $B_c \rar D,D_s(J^{P}=0^{-}) l^{+}l^{-}$ with
$l=\tau,\mu,e$ and $B_c \rar D,D_s(J^{P}=0^{-})\nu\bar{\nu}$ transitions are
calculated in the framework of the three point QCD sum rules. The heavy quark
effective theory limit of the form factors are computed. The branching fraction
of these decays are also evaluated and compared with the predictions of the
relativistic constituent quark model. Analyzing of such type transitions could
give useful information about the strong interactions inside the pseudoscalar
$D_{s}$ meson and its structure.


title:
The Atmospheric Mutual Coherence Function from the First and Second
  Rytov Approximations and its Comparison to That of Strong Fluctuation Theory

abstract:
  An expression for the mutual coherence function (MCF) of an electromagnetic
beam wave propagating through atmospheric turbulence is derived within the
confines of the Rytov approximation. It is shown that both the first and second
Rytov approximations are required. The Rytov MCF is then compared to that which
issues from the parabolic equation method of strong fluctuation theory. The
agreement is found to be quite good in the weak fluctuation case. However, an
instability is observed for the special case of beam wave intensities. The
source of the instabilities is identified to be the characteristic way beam
wave amplitudes are treated within the Rytov method.


title: Jumping numbers of a unibranch curve on a smooth surface

abstract:
  A formula for the jumping numbers of a curve unibranch at a singular point is
established. The jumping numbers are expressed in terms of the Enriques diagram
of the log resolution of the singularity, or equivalently in terms of the
canonical set of generators of the semigroup of the curve at the singular
point.


title: Laws of crack motion and phase-field models of fracture

abstract:
  Recently proposed phase-field models offer self-consistent descriptions of
brittle fracture. Here, we analyze these theories in the quasistatic regime of
crack propagation. We show how to derive the laws of crack motion either by
using solvability conditions in a perturbative treatment for slight departure
from the Griffith threshold, or by generalizing the Eshelby tensor to
phase-field models. The analysis provides a simple physical interpretation of
the second component of the classic Eshelby integral in the limit of vanishing
crack propagation velocity: it gives the elastic torque on the crack tip that
is needed to balance the Herring torque arising from the anisotropic interface
energy. This force balance condition reduces in this limit to the principle of
local symmetry in isotropic media and to the principle of maximum energy
release rate for smooth curvilinear cracks in anisotropic media. It can also be
interpreted physically in this limit based on energetic considerations in the
traditional framework of continuum fracture mechanics, in support of its
general validity for real systems beyond the scope of phase-field models.
Analytical predictions of crack paths in anisotropic media are validated by
numerical simulations. Simulations also show that these predictions hold even
if the phase-field dynamics is modified to make the failure process
irreversible. In addition, the role of dissipative forces on the process zone
scale as well as the extension of the results to motion of planar cracks under
pure antiplane shear are discussed.


title: Solvable model for chimera states of coupled oscillators

abstract:
  Networks of identical, symmetrically coupled oscillators can spontaneously
split into synchronized and desynchronized sub-populations. Such chimera states
were discovered in 2002, but are not well understood theoretically. Here we
obtain the first exact results about the stability, dynamics, and bifurcations
of chimera states by analyzing a minimal model consisting of two interacting
populations of oscillators. Along with a completely synchronous state, the
system displays stable chimeras, breathing chimeras, and saddle-node, Hopf and
homoclinic bifurcations of chimeras.


title: Unique factor ordering in the continuum limit of LQC

abstract:
  We show that the factor ordering ambiguities associated with the loop
quantisation of the gravitational part of the cosmological Hamiltonian
constraint, disappear at the level of Wheeler-DeWitt equation only for a
particular choice of lattice refinement model, which coincides with constraints
imposed from phenomenological and consistency arguments.


title:
Local-global principles for embedding of fields with involution into
  simple algebras with involution

abstract:
  In this paper we prove local-global principles for embedding of fields with
involution into central simple algebras with involution over a global field.
These should be of interest in study of classical groups over global fields. We
deduce from our results that in a group of type D_n, n>4 even, two weakly
commensurable Zariski-dense S-arithmetic subgroups are actually commensurable.
A consequence of this result is that given an absolutely simple algebraic
K-group G of type D_n, n>4 even, K a number field, any K-form G' of G having
the same set of isomorphism classes of maximal K-tori as G, is necessarily
K-isomorphic to G. These results lead to results about isolength and
isospectral compact hyperbolic spaces of dimension 2n-1 with n even.


title:
An integral test for the transience of a Brownian path with limited
  local time

abstract:
  We study a one-dimensional Brownian motion conditioned on a self-repelling
behaviour. Given a nondecreasing positive function f(t), consider the measures
mu_t obtained by conditioning a Brownian path so that L_s< f(s), for all s<t,
where L_s is the local time spent at the origin by time s. It is shown that the
measures mu_t are tight, and that any weak limit of mu_t as t tends to infinity
is transient provided that t^{-3/2}f(t) is integrable. We conjecture that this
condition is sharp and present a number of open problems.


title: Fermion-mediated interactions in a dilute Bose-Einstein condensate

abstract:
  We develop a diagrammatic perturbation treatment to calculate the
zero-temperature equation of state of the dilute gas mixture of a single spin
component Bose-Einstein condensate (BEC) and a normal Fermi gas of
indistinguishable (single spin) fermion particles. We find that the mean-field
description breaks down near the mechanical instability related to the phase
separation phenomenon. Our analysis shows that the instability is caused by the
competition of the usual short-range and fermion-mediated boson-boson
interactions, which result in a boson compressibility that diverges. In the low
BEC-density limit, we show that the diagrammatic analysis simplifies, we sum
part of the higher order diagrams, and we discuss the effects of other
higher-order contributions.


title: Productive Dialog During Collaborative Problem Solving

abstract:
  Collaboration is an important problem-solving skill; however, novice
collaboration generally benefits from some kind of support. One possibility for
supporting productive conversations between collaborators is to encourage pairs
of students to provide explanations for their problem-solving steps. To test
this possibility, we contrasted individuals who were instructed to self-explain
problem-solving steps with dyads who were instructed to jointly explain
problem-solving steps in the context of an intelligent tutoring system (ITS).
The results suggest that collaboratively developed explanations prompted
students to remediate their errors in dialog, as opposed to relying on the ITS
for assistance, which is provided in the form of on-demand hints. The paper
concludes with a discussion about implications for combining proven learning
interventions.


title: Genuine deformations of submanifolds II:the conformal case

abstract:
  We extend to the conformal realm the concept of genuine deformations of
submanifolds, introduced by Dajczer and the first author for the isometric
case. Analogously to that case, we call a conformal deformation of a
submanifold $M^n$ genuine if no open subset of $M^n$ can be included as a
submanifold of a higher dimensional conformally deformable submanifold in such
a way that the conformal deformation of the former is induced by a conformal
deformation of the latter. We describe the geometric structure of a submanifold
that admits a genuine conformal deformation and give several applications
showing the unifying character of this concept.


title: Functoriality for the su(3) Khovanov homology

abstract:
  We prove that Morrison and Nieh's categorification of the su(3) quantum knot
invariant is functorial with respect to tangle cobordisms. This is in contrast
to the categorified su(2) theory, which was not functorial as originally
defined. We use methods of Bar-Natan to construct explicit chain maps for each
variation of the third Reidemeister move. Then, to show functoriality, we
modify arguments used by Clark, Morrison, and Walker to show that induced chain
maps are invariant under Carter and Saito's movie moves.


title: Decaying Dark Matter and the Deficit of Dwarf Haloes

abstract:
  The hierarchical clustering inherent in Lambda-CDM cosmology seems to produce
many of the observed characteristics of large-scale structure. But some glaring
problems still remain, including the over-prediction (by a factor 10) of the
number of dwarf galaxies within the virialized population of the local group.
Several secondary effects have already been proposed to resolve this problem.
It is still not clear, however, whether the principal solution rests with
astrophysical processes, such as early feedback from supernovae, or possibly
with as yet undetermined properties of the dark matter itself. In this paper,
we carry out a detailed calculation of the dwarf halo evolution incorporating
the effects of a hypothesized dark-matter decay, D -> D'+l, where D is the
unstable particle, D' is the more massive daughter particle and l is the other,
lighter (or possibly massless) daughter particle. This process preferentially
heats the smaller haloes, expanding them during their evolution and reducing
their present-day circular velocity. We find that this mechanism can account
very well for the factor 4 deficit in the observed number of systems with
velocity 10--20 km/s compared to those predicted by the numerical simulations,
if dm/m_D' ~ 5-7 x 10^{-5}, where dm is the mass difference between the initial
and final states. The corresponding lifetime tau cannot be longer than ~30 Gyr,
but may be as short as just a few Gyr.

categories: astro-ph astro-ph.CO gr-qc hep-ph hep-th


title: Constraining Modified Gravity with Large non-Gaussianities

abstract:
  In writing a covariant effective action for single field inflation, one is
allowed to add a Gauss-Bonnet and axion-type curvature couplings. These
couplings represent modifications of gravity, and are the unique
higher-curvature terms that lead to second order equations of motion in four
dimensions. In this paper we study the observational consequences of such
couplings for models with large non-gaussianities. Our focus is on the
Gauss-Bonnet term. In particular, we study an effective action where the scalar
Lagrangian is a general function of the inflaton and its first derivative. We
show that, for large non-gaussianities, one can write $f_{NL}$ in terms of only
three parameters. The shape of $f_{NL}$ is also studied, and we find that it is
very similar to that of k-inflation. We show that the Gauss-Bonnet term
enhances the production of gravitational waves, and allows a smaller speed of
sound for scalar perturbations. This, in turn, can lead to larger
non-gaussianities which can be constrained by observations. Using current WMAP
limits on $f_{NL}$ and the tensor/scalar ratio, we put constraints on all
parameters. As an example, we show that for DBI inflation, the Gauss-Bonnet
coupling leads to an interesting observational window with both large $f_{NL}$
and a large amplitude of gravitational waves. Finally, we show that the
Gauss-Bonnet coupling admits a de-Sitter phase with a relativistic dispersion
relation for scalar perturbations.


title:
Information-theoretic limits on sparse signal recovery: Dense versus
  sparse measurement matrices

abstract:
  We study the information-theoretic limits of exactly recovering the support
of a sparse signal using noisy projections defined by various classes of
measurement matrices. Our analysis is high-dimensional in nature, in which the
number of observations $n$, the ambient signal dimension $p$, and the signal
sparsity $k$ are all allowed to tend to infinity in a general manner. This
paper makes two novel contributions. First, we provide sharper necessary
conditions for exact support recovery using general (non-Gaussian) dense
measurement matrices. Combined with previously known sufficient conditions,
this result yields sharp characterizations of when the optimal decoder can
recover a signal for various scalings of the sparsity $k$ and sample size $n$,
including the important special case of linear sparsity ($k = \Theta(p)$) using
a linear scaling of observations ($n = \Theta(p)$). Our second contribution is
to prove necessary conditions on the number of observations $n$ required for
asymptotically reliable recovery using a class of $\gamma$-sparsified
measurement matrices, where the measurement sparsity $\gamma(n, p, k) \in
(0,1]$ corresponds to the fraction of non-zero entries per row. Our analysis
allows general scaling of the quadruplet $(n, p, k, \gamma)$, and reveals three
different regimes, corresponding to whether measurement sparsity has no effect,
a minor effect, or a dramatic effect on the information-theoretic limits of the
subset recovery problem.


title: Exact Half-BPS Flux Solutions in M-theory I, Local Solutions

abstract:
  The complete eleven-dimensional supergravity solutions with 16
supersymmetries on manifolds of the form $AdS_3 \times S^3 \times S^3 \times
\Sigma$, with isometry $SO(2,2) \times SO(4) \times SO(4)$, and with either
$AdS_4 \times S^7$ or $AdS_7 \times S^4$ boundary behavior, are obtained in
exact form. The two-dimensional parameter space $\Sigma$ is a Riemann surface
with boundary, over which the product space $AdS_3 \times S^3 \times S^3$ is
warped. By mapping the reduced BPS equations to an integrable system of the
sine-Gordon/Liouville type, and then mapping this integrable system onto a
linear equation, the general local solutions are constructed explicitly in
terms of one harmonic function on $\Sigma$, and an integral transform of two
further harmonic functions on $\Sigma$. The solutions to the BPS equations are
shown to automatically solve the Bianchi identities and field equations for the
4-form field, as well as Einstein's equations. The solutions we obtain have
non-vanishing 4-form field strength on each of the three factors of $AdS_3
\times S^3 \times S^3$, and include fully back-reacted M2-branes in $AdS_7
\times S^4$ and M5-branes in $AdS_4 \times S^7$. No interpolating solutions
exist with mixed $AdS_4 \times S^7$ and $AdS_7 \times S^4$ boundary behavior.
Global regularity of these local solutions, as well as the existence of further
solutions with neither $AdS_4 \times S^7$ nor $AdS_7 \times S^4$ boundary
behavior will be studied elsewhere.


title:
Toric K\"ahler metrics seen from infinity, quantization and compact
  tropical amoebas

abstract:
  We consider the metric space of all toric K\"ahler metrics on a compact toric
manifold; when "looking at it from infinity" (following Gromov), we obtain the
tangent cone at infinity, which is parametrized by equivalence classes of
complete geodesics. In the present paper, we study the associated limit for the
family of metrics on the toric variety, its quantization, and degeneration of
generic divisors.
  The limits of the corresponding K\"ahler polarizations become degenerate
along the Lagrangian fibration defined by the moment map. This allows us to
interpolate continuously between geometric quantizations in the holomorphic and
real polarizations and show that the monomial holomorphic sections of the
prequantum bundle converge to Dirac delta distributions supported on
Bohr-Sommerfeld fibers.
  In the second part, we use these families of toric metric degenerations to
study the limit of compact hypersurface amoebas and show that in Legendre
transformed variables they are described by tropical amoebas. We believe that
our approach gives a different, complementary, perspective on the relation
between complex algebraic geometry and tropical geometry.


title: On common divisors of multinomial coefficients

abstract:
  Erd\H{o}s and Szekeres showed in 1978 that for any four positive integers
satisfying m_1+m_2 = n_1+n_2, the two binomial coefficients (m_1+m_2)!/m_1!
m_2! and (n_1+n_2)!/n_1! n_2! have a common divisor >1. The analogous statement
for families of k k-nomial coefficients (k>1) was conjectured in 1997 by David
Wasserman.
  Erd\H{o}s and Szekeres remark that if m_1, m_2, n_1, n_2 as above are all >1,
there is probably a lower bound on the common divisor in question which goes to
infinity as a function of m_1+m_2. Such a bound is here obtained.
  Results are proved that narrow the class of possible counterexamples to
Wasserman's conjecture. On the other hand, several plausible generalizations of
that conjecture are shown to be false.