title:
Tight Correlation-Function Bell Inequality for Multipartite
  $d$-Dimensional System

abstract:
  We generalize the correlation functions of the Clauser-Horne-Shimony-Holt
(CHSH) inequality to multipartite d-dimensional systems. All the Bell
inequalities based on this generalization take the same simple form as the CHSH
inequality. For small systems, numerical results show that the new inequalities
are tight and we believe this is also valid for higher dimensional systems.
Moreover, the new inequalities are relevant to the previous ones and for
bipartite system, our inequality is equivalent to the
Collins-Gisin-Linden-Masser-Popescu (CGLMP) inequality.


title:
Heisenberg's uncertainty principle for simultaneous measurement of
  positive-operator-valued measures

abstract:
  A limitation on simultaneous measurement of two arbitrary positive operator
valued measures is discussed. In general, simultaneous measurement of two
noncommutative observables is only approximately possible. Following Werner's
formulation, we introduce a distance between observables to quantify an
accuracy of measurement. We derive an inequality that relates the achievable
accuracy with noncommutativity between two observables. As a byproduct a
necessary condition for two positive operator valued measures to be
simultaneously measurable is obtained.


title: Improved Smoothed Analysis of the k-Means Method

abstract:
  The k-means method is a widely used clustering algorithm. One of its
distinguished features is its speed in practice. Its worst-case running-time,
however, is exponential, leaving a gap between practical and theoretical
performance. Arthur and Vassilvitskii (FOCS 2006) aimed at closing this gap,
and they proved a bound of $\poly(n^k, \sigma^{-1})$ on the smoothed
running-time of the k-means method, where n is the number of data points and
$\sigma$ is the standard deviation of the Gaussian perturbation. This bound,
though better than the worst-case bound, is still much larger than the
running-time observed in practice.
  We improve the smoothed analysis of the k-means method by showing two upper
bounds on the expected running-time of k-means. First, we prove that the
expected running-time is bounded by a polynomial in $n^{\sqrt k}$ and
$\sigma^{-1}$. Second, we prove an upper bound of $k^{kd} \cdot \poly(n,
\sigma^{-1})$, where d is the dimension of the data space. The polynomial is
independent of k and d, and we obtain a polynomial bound for the expected
running-time for $k, d \in O(\sqrt{\log n/\log \log n})$.
  Finally, we show that k-means runs in smoothed polynomial time for
one-dimensional instances.


title:
Functioning of the dimeric GABA(B) receptor extracellular domain
  revealed by glycan wedge scanning

abstract:
  The G-protein-coupled receptor (GPCR) activated by the neurotransmitter GABA
is made up of two subunits, GABA(B1) and GABA(B2). GABA(B1) binds agonists,
whereas GABA(B2) is required for trafficking GABA(B1) to the cell surface,
increasing agonist affinity to GABA(B1), and activating associated G proteins.
These subunits each comprise two domains, a Venus flytrap domain (VFT) and a
heptahelical transmembrane domain (7TM). How agonist binding to the GABA(B1)
VFT leads to GABA(B2) 7TM activation remains unknown. Here, we used a glycan
wedge scanning approach to investigate how the GABA(B) VFT dimer controls
receptor activity. We first identified the dimerization interface using a
bioinformatics approach and then showed that introducing an N-glycan at this
interface prevents the association of the two subunits and abolishes all
activities of GABA(B2), including agonist activation of the G protein. We also
identified a second region in the VFT where insertion of an N-glycan does not
prevent dimerization, but blocks agonist activation of the receptor. These data
provide new insight into the function of this prototypical GPCR and demonstrate
that a change in the dimerization interface is required for receptor
activation.


title:
Molecular determinants involved in the allosteric control of agonist
  affinity in the GABAB receptor by the GABAB2 subunit

abstract:
  The gamma-aminobutyric acid type B (GABAB) receptor is an allosteric complex
made of two subunits, GABAB1 (GB1) and GABAB2 (GB2). Both subunits are composed
of an extracellular Venus flytrap domain (VFT) and a heptahelical domain (HD).
GB1 binds GABA, and GB2 plays a major role in G-protein activation as well as
in the high agonist affinity state of GB1. How agonist affinity in GB1 is
regulated in the receptor remains unknown. Here, we demonstrate that GB2 VFT is
a major molecular determinant involved in this control. We show that isolated
versions of GB1 and GB2 VFTs in the absence of the HD and C-terminal tail can
form hetero-oligomers as shown by time-resolved fluorescence resonance energy
transfer (based on HTRF technology). GB2 VFT and its association with GB1 VFT
controlled agonist affinity in GB1 in two ways. First, GB2 VFT exerted a direct
action on GB1 VFT, as it slightly increased agonist affinity in isolated GB1
VFT. Second and most importantly, GB2 VFT prevented inhibitory interaction
between the two main domains (VFT and HD) of GB1. According to this model, we
propose that GB1 HD prevents the possible natural closure of GB1 VFT. In
contrast, GB2 VFT facilitates this closure. Finally, such inhibitory contacts
between HD and VFT in GB1 could be similar to those important to maintain the
inactive state of the receptor.


title:
Dominant role of GABAB2 and Gbetagamma for GABAB
  receptor-mediated-ERK1/2/CREB pathway in cerebellar neurons

abstract:
  gamma-aminobutyric acid type B (GABA(B)) receptor is an allosteric complex
made of two subunits, GABA(B1) and GABA(B2). GABA(B2) plays a major role in the
coupling to G protein whereas GABA(B1) binds GABA. It has been shown that
GABA(B) receptor activates ERK(1/2) in neurons of the central nervous system,
but the molecular mechanisms underlying this event are poorly characterized.
Here, we demonstrate that activation of GABA(B) receptor by either GABA or the
selective agonist baclofen induces ERK(1/2) phosphorylation in cultured
cerebellar granule neurons. We also show that CGP7930, a positive allosteric
regulator specific of GABA(B2), alone can induce the phosphorylation of
ERK(1/2). PTX, a G(i/o) inhibitor, abolishes both baclofen and
CGP7930-mediated-ERK(1/2) phosphorylation. Moreover, both baclofen and CGP7930
induce ERK-dependent CREB phosphorylation. Furthermore, by using LY294002, a
PI-3 kinase inhibitor, and a C-term of GRK-2 that has been reported to
sequester Gbetagamma subunits, we demonstrate the role of Gbetagamma in GABA(B)
receptor-mediated-ERK(1/2) phosphorylation. In conclusion, the activation of
GABA(B) receptor leads to ERK(1/2) phosphorylation via the coupling of GABA(B2)
to G(i/o) and by releasing Gbetagamma subunits which in turn induce the
activation of CREB. These findings suggest a role of GABA(B) receptor in
long-term change in the central nervous system.


title: Duality in spaces of finite linear combinations of atoms

abstract:
  In this note we describe the dual and the completion of the space of finite
linear combinations of $(p,\infty)$-atoms, $0<p\leq 1$ on ${\mathbb R}^n$. As
an application, we show an extension result for operators uniformly bounded on
$(p,\infty)$-atoms, $0<p < 1$, whose analogue for $p=1$ is known to be false.
Let $0 < p <1$ and let $T$ be a linear operator defined on the space of finite
linear combinations of $(p,\infty)$-atoms, $0<p < 1 $, which takes values in a
Banach space $B$. If $T$ is uniformly bounded on $(p,\infty)$-atoms, then $T$
extends to a bounded operator from $H^p({\mathbb R}^n)$ into $B$.


title: Extremal dyonic black holes in D=4 Gauss-Bonnet gravity

abstract:
  We investigate extremal dyon black holes in the Einstein-Maxwell-dilaton
(EMD) theory with higher curvature corrections in the form of the Gauss-Bonnet
density coupled to the dilaton. In the same theory without the Gauss-Bonnet
term the extremal dyon solutions exist only for discrete values of the dilaton
coupling constant $a$. We show that the Gauss-Bonnet term acts as a dyon hair
tonic enlarging the allowed values of $a$ to continuous domains in the plane
$(a, q_m)$ the second parameter being the magnetic charge. In the limit of the
vanishing curvature coupling (a large magnetic charge) the dyon solutions
obtained tend to the Reissner-Nordstr\"om solution but not to the extremal
dyons of the EMD theory. Both solutions have the same values of the horizon
radius as a function of charges. The entropy of new dyonic black holes
interpolates between the Bekenstein-Hawking value in the limit of the large
magnetic charge (equivalent to the vanishing Gauss-Bonnet coupling) and twice
this value for the vanishing magnetic charge. Although an expression for the
entropy can be obtained analytically using purely local near-horizon solutions,
its interpretation as the black hole entropy is legitimate only once the global
black hole solution is known to exist, and we obtain numerically the
corresponding conditions on the parameters. Thus, a purely local analysis is
insufficient to fully understand the entropy of the curvature corrected black
holes. We also find dyon solutions which are not asymptotically flat, but
approach the linear dilaton background at infinity. They describe magnetic
black holes on the electric linear dilaton background.


title: Reversal in time order of interactive events: Collision of inclined rods

abstract:
  In the rod and hole paradox as described by Rindler (1961 Am. J. Phys. 29
365-6), a rigid rod moves at high speed over a table towards a hole of the same
size. Observations from the inertial frames of the rod and slot are widely
different. Rindler explains these differences by the concept of differing
perceptions in rigidity. Gron and Johannesen (1993 Eur. J. Phys. 14 97-100)
confirmed this aspect by computer simulation where the shapes of the rods are
different as observed from the co-moving frames of the rod and slot. Lintel and
Gruber (2005 Eur. J. Phys. 26 19-23) presented an approach based on retardation
due to speed of stress propagation. In this paper we consider the situation
when two parallel rods collide while approaching each other along a line at an
inclination with their axis. The collisions of the top and bottom ends are
reversed in time order as observed from the two co-moving frames. This result
is explained by the concept of extended present derived from the principle of
relativity of simultaneity.


title:
Bifurcation-based parameter tuning in a model of the GnRH pulse and
  surge generator

abstract:
  We investigate a model of the GnRH pulse and surge generator, with the
definite aim of constraining the model GnRH output with respect to a
physiologically relevant list of specifications. The alternating pulse and
surge pattern of secretion results from the interaction between a GnRH
secreting system and a regulating system exhibiting fast-slow dynamics. The
mechanisms underlying the behavior of the model are reminded from the study of
the Boundary-Layer System according to the "dissection method" principle. Using
singular perturbation theory, we describe the sequence of bifurcations
undergone by the regulating (FitzHugh-Nagumo) system, encompassing the rarely
investigated case of homoclinic connexion. Basing on pure dynamical
considerations, we restrict the space of parameter search for the regulating
system and describe a foliation of this restricted space, whose leaves define
constant duration ratios between the surge and the pulsatility phase in the
whole system. We propose an algorithm to fix the parameter values to also meet
the other prescribed ratios dealing with amplitude and frequency features of
the secretion signal. We finally apply these results to illustrate the dynamics
of GnRH secretion in the ovine species and the rhesus monkey.


title: Quantum discord and quantum phase transition in spin chains

abstract:
  Quantum phase transitions of the transverse Ising and antiferromagnetic XXZ
spin S=1/2 chains are studied using quantum discord. Quantum discord allows the
measure of quantum correlations present in many-body quantum systems. It is
shown that the amount of quantum correlations increases close to the critical
points. The observations are in agreement with the information provided by the
concurrence which measures the entanglement of the many-body system.


title: Holomorphic self-maps of singular rational surfaces

abstract:
  We give a new proof of the classification of normal singular surface germs
admitting non-invertible holomorphic self-maps and due to J. Wahl. We then draw
an analogy between the birational classification of singular holomorphic
foliations on surfaces, and the dynamics of holomorphic maps. Following this
analogy, we introduce the notion of minimal holomorphic model for holomorphic
maps. We give sufficient conditions which ensure the uniqueness of such a
model.


title: Multi-wavelength study of a young open cluster NGC 7419

abstract:
  Using UBVRI Halpha CCD photometric observations and the archival NIR and
X-ray data, we have carried out a multi-wavelength study of a young star
cluster NGC 7419. An age of 22.5+/-3.0 Myr and a distance of 3230^{+330}_{-430}
pc are derived for the cluster with a higher value of color excess ratio
E(U-B)/E(B-V) than the normal one. There is an evidence for mass segregation in
this dynamically relaxed cluster with mass function slope is in agreement with
the Salpeter value. NIR and Halpha excess support the existence of a young (< 2
Myr) stellar population of Herbig Ae/Be stars (> 3.0 M_sun) indicating a second
episode of star formation in the cluster region. Using XMM-Newton observations,
we found several X-ray sources in the cluster region but none of the Herbig
Ae/Be stars is detected in X-rays. We compare the distribution of upper limits
for Herbig Ae/Be stars with the X-ray distribution functions of the T-Tauri and
the Herbig Ae/Be stars from previous studies, and found that the X-ray emission
level of these Herbig Ae/Be stars is not more than L_X ~5.2 x 10^{30} erg/s,
which is not significantly higher than for the T-Tauri stars. Therefore, X-ray
emission from Herbig Ae/Be stars could be the result of either unresolved
companion stars or a process similar to T-Tauri stars. We report an extended
X-ray emission from the cluster region NGC 7419, with a total L_X estimate of ~
1.8 x 10^31 erg/s/arcmin^2. Investigation of dust and CO map of 1 degree region
around the cluster indicates the presence of a foreground dust cloud which is
most likely associated with star forming region Sh2-154. This cloud harbors
uniformly distributed pre main sequence stars (0.1-2.0M_sun) and the star
formation in this cloud depend mostly upon the primordial fragmentation.


title:
Impact of a radius and composition variation on the solar subsurface
  layers stratification

abstract:
  Several works have reported changes of the Sun's subsurface stratification
inferred from f-mode or p-mode observations. Recently a non-homologous
variation of the subsurface layers with depth and time has been deduced from
f-modes. Progress on this important transition zone between the solar interior
and the external part supposes a good understanding of the interplay between
the different processes which contribute to this variation. This paper is the
first of a series where we aim to study these layers from the theoretical point
of view. For this first paper, we use solar models obtained with the CESAM
code, in its classical form, and analyze the properties of the computed
theoretical f-modes. We examine how a pure variation in the calibrated radius
influences the subsurface structure and we show also the impact of an
additional change of composition on the same layers. Then we use an inversion
procedure to quantify the corresponding f-mode variation and their capacity to
infer the radius variation. We deduce an estimate of the amplitude of the
11-year cyclic photospheric radius variation.


title:
Photoluminescence dispersion as a probe of structural inhomogeneity in
  silica

abstract:
  We report time-resolved photoluminescence spectra of point defects in
amorphous silicon dioxide (silica), in particular the decay kinetics of the
emission signals of extrinsic Oxygen Deficient Centres of the second type from
singlet and directly-excited triplet states are measured and used as a probe of
structural inhomogeneity. Luminescence activity in sapphire
($\alpha$-Al$_2$O$_3$) is studied as well and used as a model system to compare
the optical properties of defects in silica with those of defects embedded in a
crystalline matrix. Only for defects in silica, we observe a variation of the
decay lifetimes with emission energy and a time dependence of the first moment
of the emission bands. These features are analyzed within a theoretical model
with explicit hypothesis about the effect introduced by the disorder of
vitreous systems. Separate estimations of the homogenous and inhomogeneous
contributions to the measured emission linewidth are obtained: it is found that
inhomogeneous effects strongly condition both the triplet and singlet
luminescence activities of oxygen deficient centres in silica, although the
degree of inhomogeneity of the triplet emission turns out to be lower than that
of the singlet emission. Inhomogeneous effects appear to be negligible in
sapphire.


title: Cold guided beams of water isotopologs

abstract:
  Electrostatic velocity filtering and guiding is an established technique to
produce high fluxes of cold polar molecules. In this paper we clarify different
aspects of this technique by comparing experiments to detailed calculations. In
the experiment, we produce cold guided beams of the three water isotopologs
H2O, D2O and HDO. Their different rotational constants and orientations of
electric dipole moments lead to remarkably different Stark shift properties,
despite the molecules being very similar in a chemical sense. Therefore, the
signals of the guided water isotopologs differ on an absolute scale and also
exhibit characteristic electrode voltage dependencies. We find excellent
agreement between the relative guided fractions and voltage dependencies of the
investigated isotopologs and predictions made by our theoretical model of
electrostatic velocity filtering.


title:
Monte Carlo simulation for statistical mechanics model of ion channel
  cooperativity in cell membranes

abstract:
  Voltage-gated ion channels are key molecules for the generation and
propagation of electrical signals in excitable cell membranes. The
voltage-dependent switching of these channels between conducting and
nonconducting states is a major factor in controlling the transmembrane
voltage. In this study, a statistical mechanics model of these molecules has
been discussed on the basis of a two-dimensional spin model. A new Hamiltonian
and a new Monte Carlo simulation algorithm are introduced to simulate such a
model. It was shown that the results well match the experimental data obtained
from batrachotoxin-modified sodium channels in the squid giant axon using the
cut-open axon technique.


title:
Dynamical correlations in the Sherrington-Kirkpatrick model in a
  transverse field

abstract:
  We calculate the real-time-correlation function of the
Sherrington-Kirkpatrick spin-glass model in a transverse field. Using a careful
analysis of the perturbative expansion of the functional-integral
representation, we derive the asymptotic form of the correlation function. In
contrast to the previous works, we find for large transverse field a power-law
decay of the correlation with time $t$ as $t^{-3/2}$ at zero temperature and
$t^{-2}$ at infinite temperature. At the small field region, we also find a
significant change in the correlation which comes from the structural
difference between two paramagnetic phases.


title: Longitudinal Viscous Flow in Granular Gases

abstract:
  The flow characterized by a linear longitudinal velocity field
$u_x(x,t)=a(t)x$, where $a(t)={a_0}/({1+a_0t})$, a uniform density $n(t)\propto
a(t)$, and a uniform temperature $T(t)$ is analyzed for dilute granular gases
by means of a BGK-like model kinetic equation in $d$ dimensions. For a given
value of the coefficient of normal restitution $\alpha$, the relevant control
parameter of the problem is the reduced deformation rate $a^*(t)=a(t)/\nu(t)$
(which plays the role of the Knudsen number), where $\nu(t)\propto
n(t)\sqrt{T(t)}$ is an effective collision frequency. The relevant response
parameter is a nonlinear viscosity function $\eta^*(a^*)$ defined from the
difference between the normal stress $P_{xx}(t)$ and the hydrostatic pressure
$p(t)=n(t)T(t)$. The main results of the paper are: (a) an exact first-order
ordinary differential equation for $\eta^*(a^*)$ is derived from the kinetic
model; (b) a recursion relation for the coefficients of the Chapman--Enskog
expansion of $\eta^*(a^*)$ in powers of $a^*$ is obtained; (c) the
Chapman--Enskog expansion is shown to diverge for elastic collisions
($\alpha=1$) and converge for inelastic collisions ($\alpha<1$), in the latter
case with a radius of convergence that increases with inelasticity; (d) a
simple approximate analytical solution for $\eta^*(a^*)$, hardly
distinguishable from the numerical solution of the differential equation, is
constructed.


title:
The angular sizes of dwarf stars and subgiants - Non-linear surface
  brightness relations in BVRcIc from interferometry

abstract:
  Context: The prediction of stellar angular diameters from broadband
photometry plays an important role for different applications. In particular,
long-baseline interferometry, gravitational microlensing, extrasolar planet
transits, and many other observing techniques require accurate predictions of
the angular size of stars. These predictions are based on the surface
brightness-colour (SBC) relations. Aims: Our goal is to calibrate
general-purpose SBC relations using visible colours, the most commonly
available data for most stars. Methods: We compiled the existing long-baseline
interferometric observations of nearby dwarf and subgiant stars and the
corresponding broadband photometry in the Johnson B V and Cousins Rc Ic bands.
We then adjusted polynomial SBC models to these data. Results: Due to the
presence of spectral features that depend on the effective temperature, the SBC
relations are usually not linear for visible colours. We present polynomial
fits that can be employed with BVRcIc based colours to predict the
limb-darkened angular diameters (i.e. photospheric) of dwarf and subgiant stars
with a typical accuracy of 5%. Conclusions: The derived polynomial relations
provide a satisfactory approximation to the observed surface brightness of
nearby dwarfs and subgiants. For distant stars, the interstellar reddening
should be taken into account, and will usually introduce an additional
uncertainty to the predicted angular diameters.


title:
Estimates for parameters and characteristics of the confining
  SU(3)-gluonic field in charged pions and kaons from leptonic decays and
  chiral symmetry breaking

abstract:
  The confinement mechanism proposed earlier by the author is employed for to
compute the decay constants $f_P$ corresponding to leptonic decays $P\to
l^\pm+\nu_l$, $l=\mu, e$, where $P$ stands for any meson from $\pi^\pm$,
$K^\pm$. For this aim the weak axial form factor of $P$-meson is
nonperturbatively calculated. The study entails estimates for parameters of the
confining SU(3)-gluonic field in charged pions and kaons. The corresponding
estimates of the gluon concentrations, electric and magnetic colour field
strengths are also adduced for the mentioned field at the scales of the mesons
under consideration. Further the obtained results are applied to the problem of
chiral symmetry breaking in quantum chromodynamics (QCD). It is shown that in
chirally symmetric world masses of pions and kaons are fully determined by the
confining SU(3)-gluonic field among (massless) $u$, $d$ and $s$ quarks and not
equal to zero. Accordingly chiral symmetry is sufficiently rough approximate
one holding true only when neglecting the mentioned SU(3)-gluonic field between
quarks and no additional mechanism of the spontaneous chiral symmetry breaking
connected to the so-called Goldstone bosons is required. Finally, a possible
relation of the results obtained with a phenomenological string-like picture of
confinement is discussed too.


title: Dry Mergers: A Crucial Test for Galaxy Formation

abstract:
  We investigate the role that dry mergers play in the build-up of massive
galaxies within the cold dark matter paradigm. Implementing an empirical
shut-off mass scale for star formation, we find a nearly constant dry merger
rate of $ \sim 6 \times 10^{-5}$ Mpc$^{-3}$ Gyr$^{-1}$ at $z \leq 1$ and a
steep decline at larger z. Less than half of these mergers are between two
galaxies that are morphologically classified as early-types, and the other half
is mostly between an early-type and late-type galaxy. Latter are prime
candidates for the origin of tidal features around red elliptical galaxies. The
introduction of a transition mass scale for star formation has a strong impact
on the evolution of galaxies, allowing them to grow above a characteristic mass
scale of $M_{*,c} \sim 6.3 \times 10^{10}$ M$_{\odot}$ by mergers only. As a
consequence of this transition, we find that around $M_{*,c}$, the fraction of
1:1 mergers is enhanced with respect to unequal mass major mergers. This
suggest that it is possible to detect the existence of a transition mass scale
by measuring the relative contribution of equal mass mergers to unequal mass
mergers as a function of galaxy mass. The evolution of the high-mass end of the
luminosity function is mainly driven by dry mergers at low z. We however find
that only $10% -20%$ of galaxies more massive than $M_{*,c}$ experience dry
major mergers within their last Gyr at any given redshift $z \le 1$.


title: Meteorites and the physico-chemical conditions in the early solar nebula

abstract:
  Chondritic meteorites constitute the most ancient rock record available in
the laboratory to study the formation of the solar system and its planets.
Detailed investigations of their mineralogy, petrography, chemistry and
isotopic composition and comparison with other primitive solar system samples
such as cometary dust particles have allowed through the years to decipher the
conditions of formation of their individual components thought to have once
been free-floating pieces of dust and rocks in the early solar nebula. When put
in the context of astrophysical models of young stellar objects, chondritic
meteorites and cometary dust bring essential insights on the astrophysical
conditions prevailing in the very first stages of the solar system. Several
exemples are shown in this chapter, which include (1) high temperature
processes and the formation of chondrules and refractory inclusions, (2) oxygen
isotopes and their bearing on photochemistry and large scale geochemical
reservoirs in the nebula, (3) organosynthesis and cold cloud chemistry recorded
by organic matter and hydrogen isotopes, (4) irradiation of solids by flares
from the young Sun and finally (5) large scale transport and mixing of material
evidenced in chondritic interplanetary dust particles and samples returned from
comet Wild2 by the Stardust mission.


title:
Electrical spin injection and detection in lateral all-semiconductor
  devices

abstract:
  Electrical injection and detection of spin-polarized electrons is
demonstrated for the first time in a single wafer, all-semiconductor,
GaAs-based lateral spintronic device, employing p+-(Ga,Mn)As/n+-GaAs
ferromagnetic Esaki diodes as spin aligning contacts. The conversion of
spin-polarized holes into spin-polarized electrons via Esaki tunnelling leaves
its mark in a bias dependence of the spin-injection efficiency, which at
maximum reaches the relatively high value of 50%.


title:
Multiwavelength observations of 3C 454.3. I. The AGILE 2007 November
  campaign on the "Crazy Diamond"

abstract:
  [Abridged] We report on a multiwavelength observation of the blazar 3C 454.3
(which we dubbed "crazy diamond") carried out on November 2007 by means of the
astrophysical satellites AGILE, INTEGRAL, Swift, the WEBT Consortium, and the
optical-NIR telescope REM. 3C 454.3 is detected at a $\sim 19-\sigma$ level
during the 3-week observing period, with an average flux above 100 MeV of
$F_{\rm E>100MeV} = (170 \pm 13) \times 10^{-8}$ \phcmsec. The gamma-ray
spectrum can be fit with a single power-law with photon index $\Gamma_{\rm
GRID} = 1.73 \pm 0.16$ between 100 MeV and 1 GeV. We detect significant
day-by-day variability of the gamma-ray emission during our observations, and
we can exclude that the fluxes are constant at the 99.6% ($\sim 2.9 \sigma$)
level. The source was detected typically around 40 degrees off-axis, and it was
substantially off--axis in the field of view of the AGILE hard X-ray imager.
However, a 5-day long ToO observation by INTEGRAL detected 3C 454.3 at an
average flux of about $F_{\rm 20-200 keV} = 1.49 \times 10^{-3}$ \phcmsec with
an average photon index of $\Gamma_{\rm IBIS} = 1.75 \pm 0.24$ between 20--200
keV. Swift also detected 3C 454.3 with a flux in the 0.3--10 keV energy band in
the range $(1.23-1.40) \times 10^{-2}$ \phcmsec{} and a photon index in the
range $\Gamma_{\rm XRT} = 1.56-1.73$. In the optical band, both WEBT and REM
show an extremely variable behavior in the $R$ band. A correlation analysis
based on the entire data set is consistent with no time-lags between the
gamma-ray and the optical flux variations. Our simultaneous multifrequency
observations strongly indicate that the dominant emission mechanism between 30
MeV and 30 GeV is dominated by inverse Compton scattering of relativistic
electrons in the jet on the external photons from the broad line region.


title:
Exploring the Small Magellanic Cloud to the Faintest X-ray Fluxes:
  Source Catalog, Timing and Spectral Analysis

abstract:
  We present the results of a pair of 100 ksec Chandra observations in the
Small Magellanic Cloud to survey high mass X-ray binaries (HMXBs), stars and
LMXBs/CVs down to Lx = 4.3 x 10^32 erg/s The two SMC Deep Fields are located in
the most active star forming region of the bar, with Deep Field-1 positioned at
the most pulsar-rich location identified from previous surveys. Two new pulsars
were discovered in outburst: CXOU J004929.7-731058 (P=892s), CXOU
J005252.2-721715 (P=326s), and 3 new HMXB candidates were identified. Of 15
Be-pulsars now known in the field, 13 were detected, with pulsations seen in 9
of them. Ephemerides demonstrate that 6 of the 10 pulsars known to exhibit
regular outbursts were seen outside their periastron phase, and quiescent X-ray
emission at Lx=10^33 - 10^34 is shown to be common. Comparison with ROSAT,
ASCA, XMM-Newton catalogs resulted in positive identification of several
previously ambiguous sources. Bright optical counterparts exist for 40 of the
X-ray sources, of which 33 are consistent with early-type stars Mv<-2,
B-V<0.2), and are the subject of a companion paper. The results point to an
underlying HMXB population-density up to double that of active systems. The
full catalog of 394 point-sources is presented along with detailed analyses of
timing and spectral properties.


title:
The Stonehenge Technique. A new method for aligning coherent
  bremsstrahlung radiators

abstract:
  This paper describes a new technique for the alignment of crystal radiators
used to produce high energy, linearly polarized photons via coherent
bremsstrahlung scattering at electron beam facilities. In these experiments the
crystal is mounted on a goniometer which is used to adjust its orientation
relative to the electron beam. The angles and equations which relate the
crystal lattice, goniometer and electron beam direction are presented here, and
the method of alignment is illustrated with data taken at MAMI (the Mainz
microtron). A practical guide to setting up a coherent bremsstrahlung facility
and installing new crystals using this technique is also included.


title: Differing perceptions on the landing of the rod into the slot

abstract:
  In the usual rod and slot paradox, the rod, if it falls, was expected to fall
into the slot due to gravity. Many thought experiments have been conducted
where the presence of gravity is eliminated with the rod and slot approaching
each other along a line joining their centers, whereby the considerations come
strictly under Special Relativity. In these experiments the line of motion is
not parallel to either the axis of the rod or the slot. In this paper we
consider in detail the two cases when the rod does fall into the slot and when
the rod does not fall into the slot, each from the perspective of the co-moving
frames of the rod and the slot. We show that whether the rod falls into the
slot as determined by Galilean kinematics is also valid under relativistic
kinematics; this determination does not depend upon the magnitude of the
velocity, but only on the proper lengths and the proper angles of the rod and
slot with the line of motion. Our conclusion emphasizes the fact that the
passing (or crashing) of the rod as a wholesome event is unaffected by
relativistic kinematics. We also provide a simple formula to determine whether
or not the rod passes through the slot.


title: Stellar populations in a standard ISOGAL field in the Galactic disk

abstract:
  We aim to identify the stellar populations (mostly red giants and young
stars) detected in the ISOGAL survey at 7 and 15micron towards a field (LN45)
in the direction l=-45, b=0.0. The sources detected in the survey of the
Galactic plane by the Infrared Space Observatory are characterized based on
colour-colour and colour-magnitude diagrams. We combine the ISOGAL catalog with
the data from surveys such as 2MASS and GLIMPSE. Interstellar extinction and
distance are estimated using the red clump stars detected by 2MASS in
combination with the isochrones for the AGB/RGB branch. Absolute magnitudes are
thus derived and the stellar populations are identified based on their absolute
magnitudes and their infrared excess. A standard approach to the analysis of
ISOGAL disk observations has been established. We identify several hundred
RGB/AGB stars and 22 candidate young stellar objects in the direction of this
field in an area of 0.16 deg^2. An over-density of stellar sources is found at
distances corresponding to the distance of the Scutum-Crux spiral arm. In
addition, we determine mass-loss rates of AGB-stars using dust radiative
transfer models from the literature.


title: Force Induced DNA Melting

abstract:
  When pulled along the axis, double-strand DNA undergoes a large
conformational change and elongates roughly twice its initial contour length at
a pulling force about 70 pN. The transition to this highly overstretched form
of DNA is very cooperative. Applying force perpendicular to the DNA axis
(unzipping), double-strand DNA can also be separated into two single-stranded
DNA which is a fundamental process in DNA replication. We study the DNA
overstretching and unzipping transition using fully atomistic molecular
dynamics (MD) simulations and argue that the conformational changes of double
strand DNA associated with either of the above mentioned processes can be
viewed as force induced DNA melting. As the force at one end of the DNA is
increased the DNA start melting abruptly/smoothly after a critical force
depending on the pulling direction. The critical force fm, at which DNA melts
completely decreases as the temperature of the system is increased. The melting
force in case of unzipping is smaller compared to the melting force when the
DNA is pulled along the helical axis. In the cases of melting through
unzipping, the double-strand separation has jumps which correspond to the
different energy minima arising due to different base pair sequence. The
fraction of Watson-Crick base pair hydrogen bond breaking as a function of
force does not show smooth and continuous behavior and consists of plateaus
followed by sharp jumps.


title:
Suppression of dissipation in Nb thin films with triangular antidot
  arrays by random removal of pinning sites

abstract:
  The depinning current Ic versus applied magnetic field B close to the
transition temperature Tc of Nb thin films with randomly diluted triangular
arrays of antidots is investigated. % Our experiments confirm essential
features in Ic(B) as predicted by Reichhardt and Olson Reichhardt [Phys.Rev. B
76, 094512 (2007)]. % We show that, by introducing disorder into periodic
pinning arrays, Ic can be enhanced. % In particular, for arrays with fixed
density n_p of antidots, an increase in dilution Pd induces an increase in Ic
and decrease of the flux-flow voltage for B>Bp=n_p Phi_0.


title:
Gravitational and higher-order form factors of the pion in chiral quark
  models

abstract:
  The gravitational form factor of the pion is evaluated in two chiral quark
models and confronted to the recent full-QCD lattice data. We find good
agreement for the case of the Spectral Quark Model, which builds in the
vector-meson dominance for the charge form factor. We derive a simple relation
between the gravitational and electromagnetic form factors, holding in the
considered quark models in the chiral limit. The relation implies that the
gravitational mean squared radius is half the electromagnetic one. We also
analyze higher-order quark generalized form factors of the pion, related to
higher moments in the symmetric Bjorken X-variable of the generalized parton
distribution functions, and discuss their perturbative QCD evolution, needed to
relate the quark-model predictions to the lattice data. The values of the
higher-order quark form factors at t=0, computed on the lattice, also agree
with our quark model results within the statistical and method uncertainties.


title: Night sky at the Indian Astronomical Observatory during 2000-2008

abstract:
  We present an analysis of the optical night sky brightness and extinction
coefficient measurements in UBVRI at the Indian Astronomical Observatory (IAO),
Hanle, during the period 2003-2008. They are obtained from an analysis of CCD
images acquired at the 2 m Himalayan Chandra Telescope at IAO. Night sky
brightness was estimated using 210 HFOSC images obtained on 47 nights and
covering the declining phase of solar activity cycle-23. The zenith corrected
values of the moonless night sky brightness in mag/square arcsecs are 22.14(U),
22.42(B), 21.28(V), 20.54(R) and 18.86(I) band. This shows that IAO is a dark
site for optical observations. No clear dependency of sky brightness with solar
activity is found. Extinction values at IAO are derived from an analysis of
1325 images over 58 nights. They are found to be 0.36 in U-band, 0.21 in
B-band, 0.12 in V-band, 0.09 in R-band and 0.05 in I-band. On average,
extinction during the summer months is slightly larger than that during the
winter months. No clear evidence for a correlation between extinction in all
bands and the average night time wind speed is found. Also presented here is
the low resolution moonless optical night sky spectrum for IAO covering the
wavelength range 3000-9300 \AA. Hanle region thus has the required
characteristics of a good astronomical site in terms of night sky brightness
and extinction, and could be a natural candidate site for any future large
aperture Indian optical-infrared telescope(s).


title:
Understanding entanglement sudden death through multipartite
  entanglement and quantum correlations

abstract:
  The effect of Entanglement Sudden Death (ESD) can arise when entangling
interactions convert purely bipartite entangled states into more generally
entangled states. As a result, ESD can also be seen as a function of
partitioning of the system, not just of time, as the system partitioning
defines different (multipartite) entanglement classes. Computing both geometric
entanglement hierarchies and the generalization of concurrence allows one to
demonstrate that different methods of analysing quantum correlations provide
both qualitative and quantitatively different descriptions of two commonly
cited examples of ESD. These results follow directly from the inequivalence of
entanglement and quantum correlations, the later of which can exist in a state
without the former.


title: Local time and the pricing of time-dependent barrier options

abstract:
  A time-dependent double-barrier option is a derivative security that delivers
the terminal value $\phi(S_T)$ at expiry $T$ if neither of the continuous
time-dependent barriers $b_\pm:[0,T]\to \RR_+$ have been hit during the time
interval $[0,T]$. Using a probabilistic approach we obtain a decomposition of
the barrier option price into the corresponding European option price minus the
barrier premium for a wide class of payoff functions $\phi$, barrier functions
$b_\pm$ and linear diffusions $(S_t)_{t\in[0,T]}$. We show that the barrier
premium can be expressed as a sum of integrals along the barriers $b_\pm$ of
the option's deltas $\Delta_\pm:[0,T]\to\RR$ at the barriers and that the pair
of functions $(\Delta_+,\Delta_-)$ solves a system of Volterra integral
equations of the first kind. We find a semi-analytic solution for this system
in the case of constant double barriers and briefly discus a numerical
algorithm for the time-dependent case.


title: Supersymmetric Phenomenology in the mSUGRA Parameter Space

abstract:
  In this master thesis the possible supersymmetric phenomenologies associated
with low-mass mSUGRA are investigated. The main characteristics of the
supersymmetric mass spectrum are explained and a systematic method is presented
to predict phenomenology directly from the mass spectrum. The resulting
phenomenologies are compared to the current ATLAS benchmark points. It is found
that some phenomenological scenarios are not covered by these benchmark points.


title: Monte Carlo and large angle gluon radiation

abstract:
  We discuss the problem of incorporating recoil effects into the probabilistic
QCD evolution scheme based on the picture of colour dipoles as done in recent
Monte Carlo programs. Such a scheme correctly describes subleading soft
contributions to multiplicity distributions. However we find that a simple
receipt for incorporating recoil effects into the dipole multiplication picture
conflicts the collinear factorization and does not lead to the correct DGLAP
equation.


title:
The X-ray variability and the near-IR to X-ray spectral energy
  distribution of four low luminosity Seyfert 1 galaxies

abstract:
  We present the results from a study of the X-ray variability and the near-IR
to X-ray spectral energy distribution of four low-luminosity, Seyfert 1
galaxies. We compared their variability amplitude and broad band spectrum with
those of more luminous AGN in order to investigate whether accretion in
low-luminosity AGN operates as in their luminous counterparts. We used archival
XMM-Newton and, in two cases, ASCA data to estimate their X-ray variability
amplitude and determine their X-ray spectral shape and luminosity. We also used
archival HST data to measure their optical nuclear luminosity, and near-IR
measurements from the literature, in order to construct their near-IR to X-ray
spectra. The X-ray variability amplitude of the four Seyferts is what one would
expect, given their black hole masses. Their near-IR to X-ray spectrum has the
same shape as the spectrum of quasars which are 10^2-10^5 times more luminous.
The objects in our sample are optically classified as Seyfert 1-1.5. This
implies that they host a relatively unobscured AGN-like nucleus. They are also
of low luminosity and accrete at a low rate. They are therefore good candidates
to detect radiation from an inefficient accretion process. However, our results
suggest that they are similar to AGN which are 10^2-10^5 times more luminous.
The combination of a "radiative efficient accretion disc plus an X-ray
producing hot corona" may persist at low accretion rates as well.


title: Simplicial simple-homotopy of flag complexes in terms of graphs

abstract:
  A flag complex can be defined as a simplicial complex whose simplices
correspond to complete subgraphs of its 1-skeleton taken as a graph. In this
article, by introducing the notion of s-dismantlability, we shall define the
s-homotopy type of a graph and show in particular that two finite graphs have
the same s-homotopy type if, and only if, the two flag complexes determined by
these graphs have the same simplicial simple-homotopy type (Theorem 2.10, part
1). This result is closely related to similar results established by Barmak and
Minian (Adv. in Math., 218 (2008), 87-104) in the framework of posets and we
give the relation between the two approaches (theorems 3.5 and 3.7). We
conclude with a question about the relation between the s-homotopy and the
graph homotopy defined by Chen, Yau and Yeh (Discrete Math., 241(2001),
153-170).


title: Convexity bounds for L-functions

abstract:
  We give a sharp convexity estimate for L-functions which have a functional
equation and an Euler product.


title:
Orbital periods of cataclysmic variables identified by the SDSS. V. VLT,
  NTT and Magellan observations of nine equatorial systems

abstract:
  We present VLT and Magellan spectroscopy and NTT photometry of nine faint
cataclysmic variables (CVs) which were spectroscopically identified by the
SDSS. We measure orbital periods for five of these from the velocity variations
of the cores and wings of their Halpha emission lines. Four of the five have
orbital periods shorter than the 2-3 hour period gap observed in the known
population of CVs. SDSS J004335.14-003729.8 has an orbital period of Porb =
82.325 +/- 0.088 min; Doppler maps show emission from the accretion disc,
bright spot and the irradiated inner face of the secondary star. In its light
curve we find a periodicity which may be attributable to pulsations of the
white dwarf. SDSS J163722.21-001957.1 has Porb = 99.75 +/- 0.86 min. By
combining this new measurement with a published superhump period we estimate a
mass ratio of 0.16 and infer the physical properties and orbital inclination of
the system. For SDSS J164248.52+134751.4 we find Porb = 113.60 +/- 1.5 min. The
Doppler map of this CV shows an unusual brightness distribution in the
accretion disc which would benefit from further observations. SDSS
J165837.70+184727.4 had spectroscopic characteristics which were very different
between the SDSS spectrum and our own VLT observations, despite only a small
change in brightness. We measure Porb = 98.012 +/- 0.065 min from its narrow
Halpha emission line. Finally, SDSS J223843.84+010820.7 has a comparatively
longer period of Porb = 194.30 +/- 0.16 min. It contains a magnetic white dwarf
and, with g = 18.15, is brighter than the other objects studied here. These
results continue the trend for the fainter CVs identified by the SDSS to be
almost exclusively shorter-period objects with low mass transfer rates.


title:
A note concerning a tidying procedure and contraction groups in
  non-metrizable, totally disconnected groups

abstract:
  In a 2004 article, Udo Baumgartner and George Willis used ideas from the
structure theory of totally disconnected, locally compact groups to achieve a
better understanding of the contraction group U_f associated with an
automorphism f of such a group G, assuming that G is metrizable. (Recall that
U_f consists of all group elements x such that f^n(x) tends to the identity
element as n tends to infinity). Recently, Wojciech Jaworski showed that the
main technical tool of the latter article remains valid in the non-metrizable
case. He asserted without proof that, therefore, all results from that article
remain valid. However, metrizability enters the arguments at a second point. In
this note, we resolve this difficulty, by providing an affirmative answer to a
question posed by Willis in 2004.


title:
Structural and electronic response upon hole-doping of rare-earth iron
  oxyarsenides Nd1-xSrxFeAsO (0 < x < 0.2)

abstract:
  Hole-doping of NdFeAsO via partial replacement of Nd3+ by Sr2+ is a
successful route to obtain superconducting phases (Tc = 13.5 K for a Sr2+
content of 20%); however, the structural and electronic response with doping is
different from and non-symmetric to that in the electron-doped side of the
phase diagram.


title: More gravity solutions of AdS/CMT

abstract:
  We have generalized the gravity solutions presented in arXiv:0808.1725 and
arXiv:0808.3232 to arbitrary but even space time dimensions with the scaling
symmetry $r \to \f{r}{\lambda}, x_i \to \lambda^b x_i, t \to \lambda^a t$.
However, for $b=0$, we have the solution in arbitrary space time dimension, not
restricted to even dimensional. The physical meaning of this particular choice
of $b$ is that we can have a solution with only temporal scale invariance. From
the dual field theory point of view, the BF bound and the unitarity bound for
operators dual to scalar field is discussed.


title: Monopoles in lattice Electroweak theory

abstract:
  There exist several types of monopole - like topological defects in
Electroweak theory. We investigate properties of these objects using lattice
numerical methods. The intimate connection between them and the dynamics of the
theory is established.
  We find that the density of Nambu monopoles cannot be predicted by the choice
of the initial parameters of Electroweak theory and should be considered as the
new external parameter of the theory. We also investigate the difference
between the versions of Electroweak theory with the gauge groups $SU(2)\otimes
U(1)$ and $SU(2)\otimes U(1)/Z_2$. We do not detect any difference at $\alpha
\sim {1/128}$. However, such a difference appears in the unphysical region of
large coupling constant $\alpha > 0.1$.


title: Widths of tetraquarks with hidden charm

abstract:
  The relativistic four-quark equations are found in the framework of
coupled-channel formalism. The dynamical mixing of the meson-meson states with
the four-quark states is considered. The four-quark amplitudes of the
tetraquarks with hidden charm including u, d, s and charmed quarks are
constructed. The poles of these amplitudes determine the masses and widths of
tetraquarks.


title: A conjugate for the Bargmann representation

abstract:
  In the Bargmann representation of quantum mechanics, physical states are
mapped into entire functions of a complex variable z*, whereas the creation and
annihilation operators $\hat{a}^\dagger$ and $\hat{a}$ play the role of
multiplication and differentiation with respect to z*, respectively. In this
paper we propose an alternative representation of quantum states, conjugate to
the Bargmann representation, where the roles of $\hat{a}^\dagger$ and $\hat{a}$
are reversed, much like the roles of the position and momentum operators in
their respective representations. We derive expressions for the inner product
that maintain the usual notion of distance between states in the Hilbert space.
Applications to simple systems and to the calculation of semiclassical
propagators are presented.


title: Abelian categories in dimension 2

abstract:
  The goal of this thesis is to define a 2-dimensional version of abelian
categories, where symmetric 2-groups play the role that abelian groups played
in 1-dimensional algebra. Abelian and 2-abelian groupoid enriched categories
are defined and it is proved that homology can be developed in them, including
the existence of a long exact sequence of homology corresponding to an
extension of chain complexes. This generalises known results for symmetric
2-groups. The examples include, in addition to symmetric 2-groups, the
2-modules on a 2-ring, which form a 2-abelian groupoid enriched category.
Moreover, internal groupoids, functors and natural transformations in an
abelian category C (in particular, Baez-Crans 2-vector spaces) form a 2-abelian
groupoid enriched category if and only if the axiom of choice holds in C.


title:
Explicit solution of the linearized Einstein equations in TT gauge for
  all multipoles

abstract:
  We write out the explicit form of the metric for a linearized gravitational
wave in the transverse-traceless gauge for any multipole, thus generalizing the
well-known quadrupole solution of Teukolsky. The solution is derived using the
generalized Regge-Wheeler-Zerilli formalism developed by Sarbach and Tiglio.


title:
Hydrodynamical simulations of the jet in the symbiotic star MWC 560. II.
  Simulations beyond density balance

abstract:
  (Abridged) In the first paper of this series, we presented hydrodynamical
simulations with radiative cooling of jet models with parameters representative
of the symbiotic system MWC 560. These were jet simulations of a pulsed,
initially underdense jet in a high-density ambient medium. They were stopped
when the jet reached a length of 50 AU. There, however, a transition of the
initially underdense jet towards an overdense jet should occur, which should
result in changed kinematics. Therefore, we describe two hydrodynamical
simulations with cooling beyond this density balance, one with the same
parameters as model i in Paper I (now called model i'), which was presented
there with and without cooling, and the second with higher gas densities in the
jet pulses (model iv'). Hydrodynamical simulations, with a further approximated
cooling treatment compared to Paper I, were used to be able to enlarge the
computational domain. The transition causes changes in the expansion of the
cocoon and therefore the morphology of the jet, e.g. a larger radial width of
the jet knots. We investigate the radiation properties of the jets, the
bremsstrahlung and optical emissivities, integrated emission maps, and
synthetic absorption line profiles. The conclusion that the high observed
velocities in CH Cygni, R Aquarii, and MWC 560 favor the models with cooling is
unchanged by the transition. The observed parallel features in R Aquarii can be
produced by the internal knots or by a variable dense radiative shell of
shocked ambient medium. The absorption line profiles show that the real
parameters in MWC 560 are closer to model iv' than to model i'.


title:
Detecting Chameleons: The Astronomical Polarization Produced by
  Chameleon-like Scalar Fields

abstract:
  We show that a coupling between chameleon-like scalar fields and photons
induces linear and circular polarization in the light from astrophysical
sources. In this context chameleon-like scalar fields includes those of the
Olive-Pospelov (OP) model describing a varying fine structure constant. We
determine the form of this polarization numerically and give analytic
expressions in two useful limits. By comparing the predicted signal with
current observations we are able to improve the constraints on the
chameleon-photon coupling and the coupling in the OP model by over two orders
of magnitude. It is argued that, if observed, the distinctive form of the
chameleon induced circular polarization would represent a smoking gun for the
presence of a chameleon. We also report a tentative statistical detection of a
chameleon-like scalar field from observations of starlight polarization in our
galaxy.


title:
Hamiltonian Approach to 1+1 dimensional Yang-Mills theory in Coulomb
  gauge

abstract:
  We study the Hamiltonian approach to 1+1 dimensional Yang-Mills theory in
Coulomb gauge, considering both the pure Coulomb gauge and the gauge where in
addition the remaining constant gauge field is restricted to the Cartan
algebra. We evaluate the corresponding Faddeev-Popov determinants, resolve
Gauss' law and derive the Hamiltonians, which differ in both gauges due to
additional zero modes of the Faddeev-Popov kernel in the pure Coulomb gauge. By
Gauss' law the zero modes of the Faddeev-Popov kernel constrain the physical
wave functionals to zero colour charge states. We solve the Schroedinger
equation in the pure Coulomb gauge and determine the vacuum wave functional.
The gluon and ghost propagators and the static colour Coulomb potential are
calculated in the first Gribov region as well as in the fundamental modular
region, and Gribov copy effects are studied. We explicitly demonstrate that the
Dyson-Schwinger equations do not specify the Gribov region while the
propagators and vertices do depend on the Gribov region chosen. In this sense,
the Dyson-Schwinger equations alone do not provide the full non-abelian quantum
gauge theory, but subsidiary conditions must be required. Implications of
Gribov copy effects for lattice calculations of the infrared behaviour of
gauge-fixed propagators are discussed. We compute the ghost-gluon vertex and
provide a sensible truncation of Dyson-Schwinger equations. Approximations of
the variational approach to the 3+1 dimensional theory are checked by
comparison to the 1+1 dimensional case.


title: Distortion of Wigner molecules : pair function approach

abstract:
  We considered a two dimensional three electron quantum dot in a magnetic
field in the Wigner limit. A unitary coordinate transformation decouples the
Hamiltonian (with Coulomb interaction between the electrons included) into a
sum of three independent pair Hamiltonians. The eigen-solutions of the pair
Hamiltonian provide a spectrum of pair states. Each pair state defines the
distance of the two electrons involved in this state. In the ground state for
given pair angular momentum $m$, this distance increases with increasing $|m|$.
The pair states have to be occupied under consideration of the Pauli exclusion
principle, which differs from that for one-electron states and depends on the
total spin $S$ and the total orbital angular momentum $M_L=\sum m_i$ (sum over
all pair angular momenta). We have shown that the three electrons in the ground
state of the Wigner molecule form an equilateral triangle (as might be
expected) only, if the state is a quartet ($S=3/2$) and the orbital angular
momentum is a magic quantum number ($M_L=3 m ; m=$ integer). Otherwise the
triangle in the ground state is isosceles. For $M_L=3 m+1$ one of the sides is
longer and for $M_L=3 m-1$ one of the sides is shorter than the other two.


title: Single-photon excitation of surface plasmon polaritons

abstract:
  We provide the quantum mechanical description of the excitation of surface
plasmon polaritons on metal surfaces by single-photons. An
attenuated-reflection setup is described for the quantum excitation process in
which we find remarkably efficient photon-to-surface plasmon
wavepacket-transfer. Using a fully quantized treatment of the fields, we
introduce the Hamiltonian for their interaction and study the quantum
statistics during transfer with and without losses in the metal.


title: Eighty Years of Neutrino Physics

abstract:
  This is a pedagogical overview of neutrino physics from the invention of
neutrino by Pauli in 1930 to the precise measurement of neutrino mass and
mixing parameters via neutrino oscillation experiments in recent years. I have
tried to pitch it at the level of undergraduate students, occasionally cutting
corners to avoid the use of advanced mathematical tools. I hope it will be
useful in introducing this exciting field to a broad group of young physicists.


title: Tunneling D0-branes

abstract:
  In the D0-D4-brane system, D0-branes do not tunnel. Instead, they form bound
states with the D4-brane, whose ground states are exact. However, the D0-brane
quantum mechanics contains a BPS instanton. To what does this solution
correspond? We find that such a tunneling solution provides non-perturbative
corrections to the Berry phase connection for the first-excited states as the
D4-branes are moved adiabatically. We compute this connection for the first
four excited states, and show that it gives an emergent SO(5) connection
described previously by Tchrakian.


title:
The extension of Buckley-Feuring solutions for non-polynomial fuzzy
  partial differential equations

abstract:
  This paper presents the natural extension of Buckley-Feuring method proposed
in \cite{BuckleyFeuring99} for solving fuzzy partial differential equations
(FPDE) in a non-polynomial relation, such as the operator $\varphi(D_{x_1},
D_{x_2})$, which maps to the quotient between both partials. The new
assumptions and conditions proceedings from this consideration are given in
this document.


title: Pion and kaon structures from the instanton vacuum

abstract:
  In this presentation, we briefly review recent investigations on pion and
kaon structures from the instanton vacuum. Starting from the low-energy QCD
partition function, we have computed the Gasser-Leutwyler low-energy constants,
electromagnetic form factors of the pion and kaon, semileptonic decay form
factors of the kaon, and light-cone distribution amplitues of the pion and
kaon. The results are in good agreement with the experimental and empirical
data.


title: A Nonperturbative Test of M2-Brane Theory

abstract:
  We discuss non-perturbative effects in the ABJM model due to monopole
instantons. We begin by constructing the instanton solutions in the $U(2)\times
U(2)$ model, explicitly, and computing the Euclidean action. The Wick-rotated
Lagrangian is complex and its BPS monopole instantons are found to be a
delicate version of the usual 't Hooft-Polyakov monopole solutions. They are
generically 1/3 BPS but become 1/2 BPS at special locus in the moduli space of
two M2-branes, yet each instanton carries eight fermionic zero modes,
regardless of the vacuum choice. The low energy effective action induced by
monopole instantons are quartic order in derivatives. The resulting vertices
are nonperturbative in $1/k$, as expected, but are rational functions of the
vacuum moduli. We also analyze the system of two M2-branes in the supergravity
framework and compute the higher order interactions via 11-dimensional
supergraviton exchange. The comparison of the two shows that the instanton
vertices are precisely reproduced by this M2-brane picture, supporting the
proposal that the ABJM model describes multiple M2-branes.


title: HI and star formation in the most metal-deficient galaxies

abstract:
  We present Giant Metrewave Radio Telescope (GMRT) observations for three
(viz., DDO 68, SDSS J2104-0035 and UGC 772) of the six most metal-deficient
actively star-forming galaxies known. Although there is a debate as to whether
these galaxies are undergoing their first episode of star formation or not,
they are `young' in the sense that their ISM is chemically unevolved. In this
regard, they are the nearest equivalents of young galaxies in the early
Universe. All three galaxies, that we have observed, have irregular HI
morphologies and kinematics, which we interpret as either due to tidal
interaction with neighbouring galaxies, or the consequences of a recent merger.
The remaining three of the six most metal-deficient galaxies are also known to
have highly disturbed HI distributions and are interacting. It is interesting
because these galaxies were chosen solely on the basis of their metallicity and
not for any particular signs of interaction. In this sense (i.e., their gas has
not yet had time to settle into a regular disc), one could regard these
extremely metal deficient (XMD) galaxies as `young'. The current star formation
episode is likely to have been triggered by interaction/merger. It is also
possible that the tidal interaction has lead to enhanced mixing with metal-poor
gas in outer disc, and hence to a low gas-phase metallicity in the central
star-forming regions. We also find that in general these galaxies do not show a
one-to-one correspondence between regions of high HI column density and regions
with current star formation. However, to the extent that one can define a
threshold density, its value (~10^{21} atoms cm^{-2}) is similar to that in
galaxies with much higher metallicity.


title: Compatible associative products and trees

abstract:
  We compute dimensions of graded components for free algebras with two
compatible associative products, and give a combinatorial interpretation of
these algebras in terms of planar rooted trees.


title:
Strong polarization-induced reduction of addition energies in
  single-molecule nanojunctions

abstract:
  We address polarization-induced renormalization of molecular levels in
solid-state based single-molecule transistors and focus on an organic conjugate
molecule where a surprisingly large reduction of the addition energy has been
observed. We have developed a scheme that combines a self-consistent solution
of a quantum chemical calculation with a realistic description of the screening
environment. Our results indeed show a large reduction, and we explain this to
be a consequence of both (a) a reduction of the electrostatic molecular
charging energy and (b) polarization induced level shifts of the HOMO and LUMO
levels. Finally, we calculate the charge stability diagram and explain at a
qualitative level general features observed experimentally.


title: Geometrical Frustration: A Study of 4d Hard Spheres

abstract:
  The smallest maximum kissing-number Voronoi polyhedron of 3d spheres is the
icosahedron and the tetrahedron is the smallest volume that can show up in
Delaunay tessalation. No periodic lattice is consistent with either and hence
these dense packings are geometrically frustrated. Because icosahedra can be
assembled from almost perfect tetrahedra, the terms "icosahedral" and
"polytetrahedral" packing are often used interchangeably, which leaves the true
origin of geometric frustration unclear. Here we report a computational study
of freezing of 4d hard spheres, where the densest Voronoi cluster is compatible
with the symmetry of the densest crystal, while polytetrahedral order is not.
We observe that, under otherwise comparable conditions, crystal nucleation in
4d is less facile than in 3d. This suggest that it is the geometrical
frustration of polytetrahedral structures that inhibits crystallization.


title: Dissipation induced coherence of a two-mode Bose-Einstein condensate

abstract:
  We discuss the dynamics of a Bose-Einstein condensate in a double-well trap
subject to phase noise and particle loss. The phase coherence of a
weakly-interacting condensate as well as the response to an external driving
show a pronounced stochastic resonance effect: Both quantities become maximal
for a finite value of the dissipation rate matching the intrinsic time scales
of the system. Even stronger effects are observed when dissipation acts in
concurrence with strong inter-particle interactions, restoring the purity of
the condensate almost completely and increasing the phase coherence
significantly.


title:
A Regularized Method for Selecting Nested Groups of Relevant Genes from
  Microarray Data

abstract:
  Gene expression analysis aims at identifying the genes able to accurately
predict biological parameters like, for example, disease subtyping or
progression. While accurate prediction can be achieved by means of many
different techniques, gene identification, due to gene correlation and the
limited number of available samples, is a much more elusive problem. Small
changes in the expression values often produce different gene lists, and
solutions which are both sparse and stable are difficult to obtain. We propose
a two-stage regularization method able to learn linear models characterized by
a high prediction performance. By varying a suitable parameter these linear
models allow to trade sparsity for the inclusion of correlated genes and to
produce gene lists which are almost perfectly nested. Experimental results on
synthetic and microarray data confirm the interesting properties of the
proposed method and its potential as a starting point for further biological
investigations


title: Evidence for $B^0 \to \chi_{c1} \pi ^0$ at Belle

abstract:
  We present a measurement of the branching fraction for the Cabibbo- and
color-suppressed $B^0 \to \chi_{c1}\pi^0$ decay based on a data sample of
$657\times 10^6$ $B\bar B$ events collected at the $\Upsilon(4S)$ resonance
with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. We
observe a signal of $40\pm9$ events with a significance of $4.7\sigma$
including systematic uncertainties. The measured branching fraction is
$\mathcal {B}(B^0 \to \chi_{c1} \pi^0) = (1.12\pm 0.25(\rm {stat.})\pm
0.12({\rm syst.}))\times 10^{-5}$.


title:
Transition from Casimir to van der Waals force between macroscopic
  bodies

abstract:
  The transition of van der Waals to Casimir forces between macroscopic gold
surfaces is investigated by Atomic Force Microscopy in the plane-sphere
geometry. It was found that the transition appears to take place at separations
about 10 % the plasma wavelength for evaporated gold surfaces, which compares
to theoretical predictions by incorporation of experimental optical data and
roughness corrections. Moreover, the force data allow estimation of the Hamaker
constant AH in the van der Waals regime, which is in good agreement with the
Lifshitz theory predictions (even if roughness corrections are taken into
account) and former surface force apparatus measurements.


title:
Multi-Loop Results, Charm- and Bottom-Quark Masses and the Strong
  Coupling Constant

abstract:
  The impact of recent multi-loop calculations on precise determinations of
charm- and bottom-quark masses and the strong coupling constant is discussed.


title: Chiral Parametrization of QCD Vector Field in SU(3)

abstract:
  The chiral parametrization of gluons in SU(3) QCD is proposed extending an
approach developed earlier for SU(2) case. A color chiral field is introduced,
gluons are chirally rotated, and vector component of rotated gluons is defined
on condition that no new color variables appeared with the chiral field. This
condition associates such a vector component with SU(3)/U(2) coset plus an U(2)
field. The topological action in SU(3) QCD is derived. It is expressed in terms
of axial vector component of rotated gluons. The vector field in CP^2 sector is
studied in new variables of chiral parametrization.


title: Evolved Stars in the Core of the Massive Globular Cluster NGC 2419

abstract:
  We present an analysis of optical and ultraviolet Hubble Space Telescope
photometry for evolved stars in the core of the distant massive globular
cluster NGC 2419. We characterize the horizontal branch (HB) population in
detail including corrections for incompleteness on the long blue tail. We
present a method for removing (to first order) lifetime effects from the
distribution of HB stars to facilitate more accurate measurements of helium
abundance for clusters with blue HBs and to clarify the distribution of stars
reaching the zero-age HB. The population ratio R = N_HB / N_RGB implies there
may be slight helium enrichment among the EHB stars in the cluster, but that it
is likely to be small (dY < 0.05). An examination of the upper main sequence
does not reveal any sign of multiple populations. Through comparisons of
optical CMDs, we present evidence that the EHB clump in NGC 2419 contains the
end of the canonical horizontal branch, and that the boundary between the
normal HB stars and blue hook stars shows up as a change in the density of
stars in the CMD. This corresponds to a spectroscopically-verified gap in NGC
2808 and an "edge" in omega Cen. The more clearly visible HB gap at V = 23.5
appears to be too bright.(Abridged)


title:
On the tidal evolution of the orbits of low-mass satellites around black
  holes

abstract:
  Low-mass satellites, like asteroids and comets, are expected to be present
around the black hole at the Galactic center. We consider small bodies orbiting
a black hole, and we study the evolution of their orbits due to tidal
interaction with the black hole. In this paper we investigate the consequences
of the existence of plunging orbits when a black hole is present. We are
interested in finding the conditions that exist when capture occurs. The main
difference between the Keplerian and black hole cases is in the existence of
plunging orbits. Orbital evolution, leading from bound to plunging orbits, goes
through a final unstable circular orbit. On this orbit, tidal energy is
released on a characteristic black hole timescale. This process may be relevant
for explaining how small, compact clumps of material can be brought onto
plunging orbits, where they may produce individual short duration accretion
events. The available energy and the characteristic timescale are consistent
with energy released and the timescale typical of Galactic flares.


title:
Effect of structural defects on anomalous ultrasound propagation in
  solids during second-order phase transitions

abstract:
  The effect of structural defects on the critical ultrasound attenuation and
ultrasound velocity dispersion in Ising-like three-dimensional systems is
studied. A field-theoretical description of the dynamic effects of
acoustic-wave propagation in solids during phase transitions is performed with
allowance for both fluctuation and relaxation attenuation mechanisms. The
temperature and frequency dependences of the scaling functions of the
attenuation coefficient and the ultrasound velocity dispersion are calculated
in a two-loop approximation for pure and structurally disordered systems, and
their asymptotic behavior in hydrodynamic and critical regions is separated. As
compared to a pure system, the presence of structural defects in it is shown to
cause a stronger increase in the sound attenuation coefficient and the sound
velocity dispersion even in the hydrodynamic region as the critical temperature
is reached. As compared to pure analogs, structurally disordered systems should
exhibit stronger temperature and frequency dependences of the acoustic
characteristics in the critical region.


title:
VIMOS-VLT Integral Field Kinematics of the Giant Low Surface Brightness
  Galaxy ESO 323-G064

abstract:
  Aims:We have studied the bulge and the disk kinematics of the giant low
surface brightness galaxy ESO 323-G064 in order to investigate its dynamical
properties and the radial mass profile of the dark matter (DM) halo.
  Methods:We observed the galaxy with integral field spectroscopy (VLT/VIMOS,
in IFU configuration), measured the positions of the ionized gas by fitting
Gaussian functions to the O[III] and Hbeta emission lines, and fit stellar
templates to the galaxy spectra to determine velocity and velocity dispersions.
We modeled the stellar kinematics in the bulge with spherical isotropic Jeans
models and explored the implications of self consistent and dark matter
scenarios for NFW and pseudo isothermal halos.
  Results:In the bulge-dominated region, r<5", the emission lines show
multi-peaked profiles. The disk dominated region of the galaxy, 13"<r<30",
exhibits regular rotation, with a flat rotation curve that reaches 248 +/- 6
km/sec. From this we estimate the total barionic mass to be M_bar ~ 1.9 10^11
M_sun and the total DM halo mass to be M_DM ~ 4.8 10^12 M_sun. The stellar
velocity and velocity dispersion have been measured only in the innermost ~5"
of the bulge, and reveal a regular rotation with an observed amplitude of 140
km/sec and a central dispersion of sigma=180 km/sec. Our simple Jeans modeling
shows that dark matter is needed in the central 5" to explain the kinematics of
the bulge, for which we estimate a mass of (7 +/- 3) 10^10 M_sun. However, we
are not able to disentangle different DM scenarios. The computed central mass
density of the bulge of ESO 323-G064 resembles the central mass density of some
high surface brightness galaxies, rather than that of low surface brightness
galaxies.


title:
Geometric interpretation for A-fidelity and its relation with Bures
  fidelity

abstract:
  A geometric interpretation for the A-fidelity between two states of a qubit
system is presented, which leads to an upper bound of the Bures fidelity. The
metrics defined based on the A-fidelity are studied by numerical method. An
alternative generalization of the A-fidelity, which has the same geometric
picture, to a $N$-state quantum system is also discussed.


title: 3-Dimensional Lattice Polytopes Without Interior Lattice Points

abstract:
  A theorem of Howe states that every 3-dimensional lattice polytope $P$ whose
only lattice points are its vertices, is a Cayley polytope, i.e. $P$ is the
convex hull of two lattice polygons with distance one. We want to generalize
this result by classifying 3-dimensional lattice polytopes without interior
lattice points. The main result will be, that they are up to finite many
exceptions either Cayley polytopes or there is a projection, which maps the
polytope to the double unimodular 2-simplex. To every such polytope we
associate a smooth projective surface of genus 0.


title: Deconstructing the Quantum Debate: Toward a Non-Classical Epistemology

abstract:
  This article focuses on the problem of the authenticity of knowledge. It
argues that the failure to integrate the observer into the act of observing is
the main source of the disagreements and divisions in contemporary science and
scholarship. The article uses the quantum debate as a case study to illustrate
this point. It also argues that a truly non-classical epistemology should
abandon the traditional subject-object orientation and focus on the very
process of construction which creates both the subject and the object. The
understanding of this process in terms of the equilibrium between equilibrium
and disequilibrium will be critical for such epistemological perspective. The
article concludes with some illustrations that show how the new perspective can
help resolve the paradoxes which plague contemporary knowledge.
  Key words: the quantum debate, non-classical epistemology, paradox of
observing


title: Special symmetries of Banach spaces isomorphic to Hilbert spaces

abstract:
  In this paper Hilbert spaces are characterized among Banach spaces in terms
of transitivity with respect to nicely behaved subgroups of the isometry group.
For example, the following result is typical here: If X is a real Banach space
isomorphic to a Hilbert space and convex-transitive with respect to the
isometric finite-dimensional perturbations of the identity, then X is already
isometric to a Hilbert space.


title: Cellular Automata as a Model of Physical Systems

abstract:
  Cellular Automata (CA), as they are presented in the literature, are abstract
mathematical models of computation. In this pa- per we present an alternate
approach: using the CA as a model or theory of physical systems and devices.
While this approach abstracts away all details of the underlying physical
system, it remains faithful to the fact that there is an underlying physical
reality which it describes. This imposes certain restrictions on the types of
computations a CA can physically carry out, and the resources it needs to do
so. In this paper we explore these and other consequences of our
reformalization.


title: Mirror Quintics, discrete symmetries and Shioda Maps

abstract:
  In a recent paper, Doran, Greene and Judes considered one parameter families
of quintic threefolds with finite symmetry groups. A surprising result was that
each of these six families has the same Picard Fuchs equation associated to the
holomorphic 3-form. In this paper we give an easy argument, involving the
family of Mirror Quintics, which implies this result. Using a construction due
to Shioda, we also relate certain quotients of these one parameter families to
the family of Mirror Quintics. Our constructions generalize to degree n Calabi
Yau varieties in (n-1)-dimensional projective space.


title: Geometry of phase separation

abstract:
  We study the domain geometry during spinodal decomposition of a 50:50 binary
mixture in two dimensions. Extending arguments developed to treat non-conserved
coarsening, we obtain approximate analytic results for the distribution of
domain areas and perimeters during the dynamics. The main approximation is to
regard the interfaces separating domains as moving independently. While this is
true in the non-conserved case, it is not in the conserved one. Our results can
therefore be considered as a first-order approximation for the distributions.
In contrast to the celebrated Lifshitz-Slyozov-Wagner distribution of
structures of the minority phase in the limit of very small concentration, the
distribution of domain areas in the 50:50 case does not have a cut-off. Large
structures (areas or perimeters) retain the morphology of a percolative or
critical initial condition, for quenches from high temperatures or the critical
point respectively. The corresponding distributions are described by a $c
A^{-\tau}$ tail, where $c$ and $\tau$ are exactly known. With increasing time,
small structures tend to have a spherical shape with a smooth surface before
evaporating by diffusion. In this regime the number density of domains with
area $A$ scales as $A^{1/2}$, as in the Lifshitz-Slyozov-Wagner theory. The
threshold between the small and large regimes is determined by the
characteristic area, ${\rm A} \sim [\lambda(T) t]^{2/3}$. Finally, we study the
relation between perimeters and areas and the distribution of boundary lengths,
finding results that are consistent with the ones summarized above. We test our
predictions with Monte Carlo simulations of the 2d Ising Model.


title:
The advection-dominated accretion flow+thin accretion disk model for two
  low-luminosity active galactic nuclei: M81 and NGC4579

abstract:
  It was found that the advection-dominated accretion flow (ADAF)+thin disk
model calculations can reproduce the observed spectral energy distributions
(SED) of the two low luminosity AGN, provided they are accreting at ~0.01-0.03
Eddington rates and the thin disks are truncated to ADAFs at ~100 R_s
(Schwarzschild radii) for M81 and NGC4579 (Quataert et al., 1999). However, the
black hole masses adopted in their work are about one order of magnitude lower
than recent measurements on these two sources. Adopting the well estimated
black hole masses, our ADAF+thin disk model calculations can reproduce the
observed SEDs of these two LLAGN, if the black hole is accreting at 2.5e-4
Eddington rates with the thin disk truncated at 120 R_s for M81 (3.3e-3 and
R_tr = 80R_s are required for NGC4579). The observed widths of the thermal
X-ray iron lines at 6.8 keV are consistent with the Doppler broadening by the
Keplerian motion of the gases in the transition zones at ~100R_s. The observed
thermal X-ray lines provide a useful diagnosis on the physical properties of
the transition zones. We calculate the thermal X-ray line emission from the
transition zone between the ADAF and the thin disk with standard software
package Astrophysical Plasma Emission Code (APEC), and the physical
implications on the models of the transition zones are discussed.


title:
Comment on "Dual path integral representation for finite temperature
  quantum field theory"

abstract:
  I show that the novel dual path integral representation for finite
temperature quantum field theory proposed in [Phys. Rev. D 77, 105030 (2008),
arXiv:0803.1667 ] is a well-known representation of quantum mechanics in terms
of symbols of operators.


title: Two photon decays of scalar mesons in the quark NJL model

abstract:
  Two photon decays of scalar mesons f_0(980), a_0(980), \sigma(600) in the
quark Nambu - Jona - Lasinio (NJL) model are calculated. The contributions of
the meson loops are taken into account along with the quark loops (Hartree -
Fock approximation). This corresponds to the next order of the 1/N_c expansion,
where
  N_c=3 is the number of quark colors. It is shown that the meson and quark
loops give comparable contributions to the amplitude. Moreover, in the process
f_0(980)-> \gamma \gamma the kaon loop plays the dominant role. A similar
situation takes place in the decay
  \phi -> f_0(980) \gamma \cite{physrev}.
  Our results are in satisfactory agreement with the recent experimental data.


title: Extended Emission of Short Gamma-Ray Bursts

abstract:
  Preliminary results of our analysis on the extended emission of short/medium
duration GRBs observed with Swift/BAT are presented. The Bayesian blocks
algorithm is used to analyze the burst durations and the temporal structure of
the lightcurves in different energy bands. We show here the results of three
bursts (GRBs 050724, 061006 and 070714B) that have a prominent soft extended
emission component in our sample. The extended emission of these bursts is a
continuous, flickering-liked component, lasting $\sim 100$ seconds post the GRB
trigger at 15-25 keV bands. Without considering this component, the three
bursts are classified as short GRBs, with $T_{90}=2\sim 3$ seconds. GRB 060614
has an emission component similar to the extended emission, but this component
has pulse-liked structure, possibly indicating that this emission component is
different from that observed in GRBs 050724, 061006, and 070714B. Further
analysis on the spectral evolution behavior of the extended emission component
is on going.


title:
Membrane-Protein Interactions in a Generic Coarse-Grained Model for
  Lipid Bilayers

abstract:
  We study membrane-protein interactions and membrane-mediated protein-protein
interactions by Monte Carlo simulations of a generic coarse-grained model for
lipid bilayers with cylindrical hydrophobic inclusions. The strength of the
hydrophobic force and the hydrophobic thickness of the proteins are
systematically varied. The results are compared with analytical predictions of
two popular analytical theories: The Landau-de Gennes theory and the elastic
theory. The elastic theory provides an excellent description of the fluctuation
spectra of pure membranes and successfully reproduces the deformation profiles
of membranes around single proteins. However, its prediction for the potential
of mean force between proteins is not compatible with the simulation data for
large distances. The simulations show that the lipid-mediated interactions are
governed by five competing factors: Direct interactions, lipid-induced
depletion interactions, lipid bridging, lipid packing, and a smooth long-range
contribution. The mechanisms leading to "hydrophobic mismatch" interactions are
critically analyzed.


title:
Drainage of a nanoconfined simple fluid: rate effects on squeeze-out
  dynamics

abstract:
  We investigate the effect of loading rate on drainage in molecularly thin
films of a simple fluid made of quasi-spherical molecules
(octamethylcyclotetrasiloxane, OMCTS). We find that (i) rapidly confined OMCTS
retains its tendency to organize into layers parallel to the confining
surfaces, and (ii) flow resistance in such layered films can be described by
bulklike viscous forces if one accounts for the existence of one monolayer
immobilized on each surfaces. The latter result is fully consistent with the
recent work of Becker and Mugele, who reached a similar conclusion by analyzing
the dynamics of squeeze-out fronts in OMCTS [T. Becker and F. Mugele, Phys.
Rev. Lett. {\bf 91} 166104(2003)]. Furthermore, we show that the confinement
rate controls the nature of the thinning transitions: layer-by-layer expulsion
of molecules in metastable, slowly confined films proceeds by a
nucleation/growth mechanism, whereas deeply and rapidly quenched films are
unstable and undergo thinning transitions akin to spinodal decomposition.


title:
Superconducting BCS versus Fulde-Ferrell-Larkin-Ovchinnikov states of
  quasiparticles with spin dependent mass and their distinguishability

abstract:
  The first observation of the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO)
superconducting state and a subsequent detection of the spin-dependent
effective masses of quasiparticles in the CeCoIn_5 heavy fermion system are
combined into a single theoretical framework. The appearance of the spin-split
masses extends essentially the regime of temperatures and applied magnetic
fields, in which FFLO is observable and thus is claimed to be very important
for the FFLO detectability. We also stress that the quasiparticles composing
Cooper pair become distinguishable in the nonzero field. The analysis is
performed within the Kondo-lattice limit of the finite-U Anderson-lattice model
containing both the mass renormalization and real-space pairing within a single
scheme.


title: Formation and Evolution of Cataclysmic Variables

abstract:
  This article summarizes the basic facts and ideas concerning the formation
and evolution of cataclysmic variables (CVs). It is shown why the formation of
CVs must involve huge losses of mass and orbital angular momentum, very likely
via a common envelope evolution. A brief discussion of the principles of the
long-term evolution of semi-detached binaries follows. Finally a brief sketch
of CV evolution is given.


title: How do dynamos saturate?

abstract:
  In order better to understand how dynamo systems saturate, we study the
kinematic dynamo properties of velocity fields that arise from nonlinearly
saturated dynamos. The technique is implemented by solving concurrently, in
addition to the momentum equation, two induction equations, one for the actual
magnetic field, and one for an independent passive field. We apply this
technique to two illustrative examples: convectively driven turbulence, and
turbulence represented by a shell model. In all cases we find that the velocity
remains an efficient kinematic dynamo even after nonlinear saturation occurs.
We discuss the implications to the process of dynamo saturation.


title:
Automatic Identification and Data Extraction from 2-Dimensional Plots in
  Digital Documents

abstract:
  Most search engines index the textual content of documents in digital
libraries. However, scholarly articles frequently report important findings in
figures for visual impact and the contents of these figures are not indexed.
These contents are often invaluable to the researcher in various fields, for
the purposes of direct comparison with their own work. Therefore, searching for
figures and extracting figure data are important problems. To the best of our
knowledge, there exists no tool to automatically extract data from figures in
digital documents. If we can extract data from these images automatically and
store them in a database, an end-user can query and combine data from multiple
digital documents simultaneously and efficiently. We propose a framework based
on image analysis and machine learning to extract information from 2-D plot
images and store them in a database. The proposed algorithm identifies a 2-D
plot and extracts the axis labels, legend and the data points from the 2-D
plot. We also segregate overlapping shapes that correspond to different data
points. We demonstrate performance of individual algorithms, using a
combination of generated and real-life images.


title:
Measurement of Delta G/G from high transverse momentum hadron pairs in
  COMPASS

abstract:
  The new COMPASS Delta G/G result obtained from high transverse momentum
hadron pairs in the Q^2>1 GeV^2 region is presented. Comparing to the previous
analysis in this region the statistical error of Delta G/G is reduced by a
factor 3 to 0.10. A weighted method of the Delta G/G measurement based on
neural network approach is used. In addition, the formula for the Delta G/G
extraction used in the analysis has been updated. The contributions coming from
the leading order and QCD Compton processes are no longer neglected.


title: Influence of correlations on molecular recognition

abstract:
  The influence of the patchiness and correlations in the distribution of
hydrophobic and polar residues at the interface between two rigid biomolecules
on their recognition ability is investigated in idealised coarse-grained
lattice models. A general two-stage approach is utilised where an ensemble of
probe molecules is designed first and the recognition ability of the probe
ensemble is related to the free energy of association with both the target
molecule and a different rival molecule in a second step. The influence of
correlation effects are investigated using numerical Monte Carlo techniques and
mean field methods. Correlations lead to different optimum characteristic
lengths of the hydrophobic and polar patches for the mutual design of the two
biomolecules on the one hand and their recognition ability in the presence of
other molecules on the other hand.


title: Solutions of some nonlinear parabolic equations with initial blow-up

abstract:
  We study the existence and uniqueness of solutions of $\partial_tu-\Delta
u+u^q=0$ ($q>1$) in $\Omega\times (0,\infty)$ where $\Omega\subset\mathbb R^N$
is a domain with a compact boundary, subject to the conditions $u=f\geq 0$ on
$\partial\Omega\times (0,\infty)$ and the initial condition $\lim_{t\to
0}u(x,t)=\infty$. By means of Brezis' theory of maximal monotone operators in
Hilbert spaces, we construct a minimal solution when $f=0$, whatever is the
regularity of the boundary of the domain. When $\partial\Omega$ satisfies the
parabolic Wiener criterion and $f$ is continuous, we construct a maximal
solution and prove that it is the unique solution which blows-up at $t=0$.


title: Graph Operations that are Good for Greedoids

abstract:
  S is a local maximum stable set of a graph G, if the set S is a maximum
stable set of the subgraph induced by its closed neighborhood. In (Levit,
Mandrescu, 2002) we have proved that the family of all local maximum stable
sets is a greedoid for every forest. The cases of bipartite graphs and
triangle-free graphs were analyzed in (Levit, Mandrescu, 2004) and (Levit,
Mandrescu, 2007), respectively. In this paper we give necessary and sufficient
conditions for the family of all local maximum stable sets of a graph G to form
a greedoid, where G is: (a) the disjoint union of a family of graphs; (b) the
Zykov sum of a family of graphs, or (c) the corona X*{H_1,H_2,...,H_n} obtained
by joining each vertex k of a graph X to all the vertices of a graph H_k.


title: Twistors, strings and supersymmetric gauge theories

abstract:
  This thesis is concerned with the study of scattering amplitudes in
four-dimensional conformal field theories, more particularly the N=4
super-Yang-Mills theory. We study this theory first at tree level by using
twistor space techniques and review the twistor string models that were
proposed to describe it. Then, we turn to the issue of iteration relations and
all loop ansatze for scattering amplitudes. We review the unitarity method for
computing scattering amplitudes and discuss the Wilson loop--scattering
amplitude duality that was inspired by the strong-coupling prescription of
Alday and Maldacena for scattering amplitudes. We describe in some detail the
computation of a two-loop six-point scattering amplitude and its surprising
equality to the polygonal Wilson loop.


title: New examples of $c_0$-saturated Banach spaces

abstract:
  For every $ 1 < p < \infty $ an isomorphically polyhedral Banach space $E_p$
is constructed having an unconditional basis and admitting a quotient
isomorphic to $\ell_p$. It is also shown that $E_p$ is not isomorphic to a
subspace of a $C(K)$ space for every countable and compact metric space $K$.


title: Subdiffusive model of substance releasing from a thick membrane

abstract:
  We study both theoretically and experimentally the process of subdiffusive
substance releasing from a thick membrane. The theoretical model uses the
subdiffusion equation with fractional time derivative and specific boundary
conditions at the membrane surfaces. Using a special \textit{ansatz} we find
analytical formulas describing the time evolution of concentration profiles and
an amount of the substance remains in the membrane. Fitting the theoretical
functions to the experimental results, we estimate the subdiffusion coefficient
of polyethylene glycol 2000 in agarose hydrogel.


title: Characterization of the errors of the FMM in particle simulations

abstract:
  The Fast Multipole Method (FMM) offers an acceleration for pairwise
interaction calculation, known as $N$-body problems, from $\mathcal{O}(N^2)$ to
$\mathcal{O}(N)$ with $N$ particles. This has brought dramatic increase in the
capability of particle simulations in many application areas, such as
electrostatics, particle formulations of fluid mechanics, and others. Although
the literature on the subject provides theoretical error bounds for the FMM
approximation, there are not many reports of the measured errors in a suite of
computational experiments. We have performed such an experimental
investigation, and summarized the results of about 1000 calculations using the
FMM algorithm, to characterize the accuracy of the method in relation with the
different parameters available to the user. In addition to the more standard
diagnostic of the maximum error, we supply illustrations of the spatial
distribution of the errors, which offers visual evidence of all the
contributing factors to the overall approximation accuracy: multipole
expansion, local expansion, hierarchical spatial decomposition (interaction
lists, local domain, far domain). This presentation is a contribution to any
researcher wishing to incorporate the FMM acceleration to their application
code, as it aids in understanding where accuracy is gained or compromised.


title: Estimating intermittency in three-dimensional Navier-Stokes turbulence

abstract:
  The issue of why computational resolution in Navier-Stokes turbulence is so
hard to achieve is addressed. It is shown that Navier-Stokes solutions can
potentially behave differently in two distinct regions of space-time
$\mathbb{R}^{\pm}$ where $\mathbb{R}^{-}$ is comprised of a union of disjoint
space-time `anomalies'. Large values of $|\nabla\bom|$ dominate
$\mathbb{R}^{-}$, which is consistent with the formation of vortex sheets or
tightly-coiled filaments. The local number of degrees of freedom
$\mathcal{N}^{\pm}$ needed to resolve the regions in $\mathbb{R}^{\pm}$
satisfies $$\mathcal{N}^{\pm}(\bx, t)\lessgtr c_{\pm}\mathcal{R}_{u}^{3}$$
where $\mathcal{R}_{u} = uL/\nu$ is a Reynolds number dependent on the local
velocity field $u(\bx, t)$.


title: Topological Complexity of omega-Powers : Extended Abstract

abstract:
  This is an extended abstract presenting new results on the topological
complexity of omega-powers (which are included in a paper "Classical and
effective descriptive complexities of omega-powers" available from
arXiv:0708.4176) and reflecting also some open questions which were discussed
during the Dagstuhl seminar on "Topological and Game-Theoretic Aspects of
Infinite Computations" 29.06.08 - 04.07.08.