title: Low frequency noise in chemical vapor deposited MoS2

abstract:
  Inherent low frequency noise is a ubiquitous phenomenon, which limits
operation and performance of electronic devices and circuits. This limiting
factor is very important for nanoscale electronic devices, such as 2D
semiconductor devices. In this work, low frequency noise in high mobility
single crystal MoS2 grown by chemical vapor deposition (CVD) is investigated.
The measured low frequency noise follows an empirical formulation of mobility
fluctuations with Hooge' s parameter ranging between 1.44E-3 and 3.51E-2. Small
variation of Hooge's parameter suggests superior material uniformity and
processing control of CVD grown MoS2 devices than reported single-layer MoS2
FET. The extracted Hooge's parameter is one order of magnitude lower than CVD
grown graphene. The Hooge's parameter shows an inverse relationship with the
field mobility.


title: Secret Key Cryptosystem based on Non-Systematic Polar Codes

abstract:
  Polar codes are a new class of error correcting linear block codes, whose
generator matrix is specified by the knowledge of transmission channel
parameters, code length and code dimension. Moreover, regarding computational
security, it is assumed that an attacker with a restricted processing power has
unlimited access to the transmission media. Therefore, the attacker can
construct the generator matrix of polar codes, especially in the case of Binary
Erasure Channels, on which this matrix can be easily constructed. In this
paper, we introduce a novel method to keep the generator matrix of polar codes
in secret in a way that the attacker cannot access the required information to
decode the intended polar code. With the help of this method, a secret key
cryptosystem is proposed based on non-systematic polar codes. In fact, the main
objective of this study is to achieve an acceptable level of security and
reliability through taking advantage of the special properties of polar codes.
The analyses revealed that our scheme resists the typical attacks on the secret
key cryptosystems based on linear block codes. In addition, by employing some
efficient methods, the key length of the proposed scheme is decreased compared
to that of the previous cryptosystems. Moreover, this scheme enjoys other
advantages including high code rate, and proper error performance as well.


title:
Systemic Risk Identification, Modelling, Analysis, and Monitoring: An
  Integrated Approach

abstract:
  Research capacity is critical in understanding systemic risk and informing
new regulation. Banking regulation has not kept pace with all the complexities
of financial innovation. The academic literature on systemic risk is rapidly
expanding. The majority of papers analyse a single source or a consolidated
source of risk and its effect. A fraction of publications quantify systemic
risk measures or formulate penalties for systemically important financial
institutions that are of practical regulatory relevance. The challenges facing
systemic risk evaluation and regulation still persist, as the definition of
systemic risk is somewhat unsettled and that affects attempts to provide
solutions. Our understanding of systemic risk is evolving and the awareness of
data relevance is rising gradually; this challenge is reflected in the focus of
major international research initiatives. There is a consensus that the direct
and indirect costs of a systemic crisis are enormous as opposed to preventing
it, and that without regulation the externalities will not be prevented; but
there is no consensus yet on the extent and detail of regulation, and research
expectations are to facilitate the regulatory process. This report outlines an
integrated approach for systemic risk evaluation based on multiple types of
interbank exposures through innovative modelling approaches as tensorial
multilayer networks, suggests how to relate underlying economic data and how to
extend the network to cover financial market information. We reason about data
requirements and time scale effects, and outline a multi-model hypernetwork of
systemic risk knowledge as a scenario analysis and policy support tool. The
argument is that logical steps forward would incorporate the range of risk
sources and their interrelated effects as contributions towards an overall
systemic risk indicator, would perform an integral analysis of ...


title: Infrared-Improved Soft-wall AdS/QCD Model for Mesons

abstract:
  We construct and investigate an infrared-improved soft-wall AdS/QCD model for
mesons. Both linear confinement and chiral symmetry breaking of low energy QCD
are well characterized in such an infrared-improved soft-wall AdS/QCD model.
The model enables us to obtain a more consistent numerical prediction for the
mass spectra of resonance scalar, pseudoscalar, vector and axial-vector mesons.
In particular, the predicted mass for the lightest ground state scalar meson
shows a good agreement with the experimental data. The model also provides a
remarkable check for the Gell-Mann-Oakes-Renner relation and a sensible result
for the space-like pion form factor.


title:
On the interpretation of new late B- and early A-type periodic variable
  stars in NGC 3766

abstract:
  We investigate possible interpretations of the new periodic B- and A-type
variable stars discovered in NGC 3766. They lie in the region of the
Hertzsprung-Russell diagram between slowly pulsating B and delta Sct stars, a
region where no pulsation is predicted by standard models of pulsating stars.
We show that the two other possible causes of periodic light curve variations,
rotational modulation and binarity, cannot provide a satisfactory explanation
for all the properties observed in those stars either. The question of their
origin is thus currently an open issue.


title:
On the zeros of the $k$-th derivative of the Riemann zeta function under
  the Riemann hypothesis

abstract:
  The number of zeros and the distribution of the real part of non-real zeros
of the derivatives of the Riemann zeta function have been investigated by
Berndt, Levinson, Montgomery, and Akatsuka. Berndt, Levinson, and Montgomery
investigated the general case, meanwhile Akatsuka gave sharper estimates for
the first derivative of the Riemann zeta function under the truth of the
Riemann hypothesis. In this paper, we generalize the results of Akatsuka to the
$k$-th derivative (for positive integer $k$) of the Riemann zeta function.


title: Local convertibility of the ground state of the perturbed Toric code

abstract:
  We present analytical and numerical studies of the behaviour of the
$\alpha$-Renyi entropies in the Toric code in presence of several types of
perturbations aimed at studying the simulability of these perturbations to the
parent Hamiltonian using local operations and classical communications (LOCC) -
a property called local-convertibility. In particular, the derivatives, with
respect to the perturbation parameter, present different signs for different
values of $\alpha$ within the topological phase. From the information-theoretic
point of view, this means that such ground states cannot be continuously
deformed within the topological phase by means of catalyst assisted local
operations and classical communications (LOCC). Such LOCC differential
convertibility is on the other hand always possible in the trivial disordered
phase. The non-LOCC convertibility is remarkable because it can be computed on
a system whose size is independent of correlation length. This method can
therefore constitute an experimentally feasible witness of topological order.


title: Development of a sub-milimeter position sensitive gas detector

abstract:
  A position sensitive thin gap chamber has been developed. The position
resolution was measured using the cosmic muons. This paper presents the
structure of this detector, position resolution measurement method and results.


title:
Manipulating femtosecond magnetism through pressure: First-principles
  calculations

abstract:
  Inspired by a recent pressure experiment in fcc Ni, we propose a simple
method to use pressure to investigate the laser-induced femtosecond magnetism.
Since the pressure effect on the electronic and magnetic properties can be well
controlled experimentally, this leaves little room for ambiguity when compared
with theory. Here we report our theoretical pressure results in fcc Ni:
Pressure first suppresses the spin moment reduction, and then completely
diminishes it; further increase in pressure to 40 GPa induces a
demagnetization-to-magnetization transition. To reveal its microscopic origin,
we slide through the L-U line in the Brillouin zone and find two essential
transitions are responsible for this change, where the pressure lowers two
valence bands, resulting in an off-resonant excitation and thus a smaller spin
moment reduction. In the spin-richest L-W-W' plane, two spin contours are
formed; as pressure increases, the contour size retrieves and its intensity is
reduced to zero eventually, fully consistent with the spin-dipole factor
prediction. These striking features are detectable in time- and spin-resolved
photoemission experiments.


title:
Quasi Periodic Oscillations in a Radiative Transonic Flow: Results of a
  Coupled Monte Carlo-TVD Simulation

abstract:
  Low and intermediate frequency quasi-periodic oscillations (QPOs) in black
hole candidates are believed to be due to oscillations of the Comptonizing
regions in an accretion flow. Assuming that the general structure of an
accretion disk is a Two Component Advective Flow (TCAF), we numerically
simulate the light curves emitted from an accretion disk for different
accretion rates and find how the QPO frequencies vary. We use a standard
Keplerian disk residing at the equatorial plane as a source of soft photons.
These soft photons, after suffering multiple scattering with the hot electrons
of the low angular momentum, sub-Keplerian, flow emerge out as hard radiation.
The hydrodynamic and thermal properties of the electron cloud is simulated
using a Total Variation Diminishing (TVD) code. The TVD code is then coupled
with a radiative transfer code which simulates the energy exchange between the
electron and radiation using Monte Carlo technique. The resulting localized
heating and cooling are included also. We find that the QPO frequency increases
and the spectrum becomes softer as we increase the Keplerian disk rate.
However, the spectrum becomes harder if we increase the sub-Keplerian accretion
rate. We find that an earlier prediction that QPOs occur when the infall time
scale roughly matches with the cooling time scale, originally obtained using a
power-law cooling, remains valid even for Compton cooling. Our findings agree
with the general observations of low frequency QPOs in black hole candidates.


title: p-type doping in CVD grown MoS2 using Nb

abstract:
  We report on the first demonstration of p-type doping in large area few-layer
films of (0001)-oriented chemical vapor deposited (CVD) MoS2. Niobium was found
to act as an efficient acceptor up to relatively high density in MoS2 films.
For a hole density of 4 x 1020 cm-3 Hall mobility of 8.5 cm2V-1s-1 was
determined, which matches well with the theoretically expected values. XRD and
Raman characterization indicate that the film had good out-of-plane crystalline
quality. Absorption measurements showed that the doped sample had similar
characteristics to high-quality undoped samples, with a clear absorption edge
at 1.8 eV. This demonstration of p-doping in large area epitaxial MoS2 could
help in realizing a wide variety of electrical and opto-electronic devices
based on layered metal dichalcogenides.


title: Giant Low Surface Brightness Galaxies : Evolution in Isolation

abstract:
  Giant Low Surface Brightness (GLSB) galaxies are amongst the most massive
spiral galaxies that we know of in our Universe. Although they fall in the
class of late type spiral galaxies, their properties are far more extreme. They
have very faint stellar disks that are extremely rich in neutral hydrogen gas
but low in star formation and hence low in surface brightness. They often have
bright bulges that are similar to those found in early type galaxies. The
bulges can host low luminosity Active Galactic Nuclei (AGN) that have
relatively low mass black holes. GLSB galaxies are usually isolated systems and
are rarely found to be interacting with other galaxies. In fact many GLSB
galaxies are found under dense regions close to the edges of voids. These
galaxies have very massive dark matter halos that also contribute to their
stability and lack of evolution. In this paper we briefly review the properties
of this unique class of galaxies and conclude that both their isolation and
their massive dark matter halos have led to the low star formation rates and
the slower rate of evolution in these galaxies.


title: Sign structure and ground state properties for a spin-$S$ $t$-$J$ chain

abstract:
  The antiferromagnetic Heisenberg spin chain of odd spin $S$ is in the Haldane
phase with several defining physical properties, such as thermodynamical
ground-state degeneracy, symmetry-protected edge states, and nonzero string
order parameter. If nonzero hole concentration $\delta$ and hole hopping energy
$t$ are considered, the spin chain is replaced by a spin-$S$ $t$-$J$ chain. The
motivation of this paper is to generalize the discussions of the Haldane phase
to the doped spin chain. The \emph{first result} of this paper is that, for the
model considered here, the $\mathbb{Z}_2$ sign structure in the usual Ising
basis can be totally removed by two consecutive unitary transformations
consisting of a spatially local one and a nonlocal one. Direct from the sign
structure, the \emph{second result} of this paper is that the Marshall theorem
and the Lieb-Mattis theorem for pure spin systems are generalized to the
$t$-$J$ chain for arbitrary $S$ and $\delta$. A corollary of the theorem
provides us with the ground-state degeneracy in the thermodynamic limit. The
\emph{third result} of this paper is about the phase diagram. We show that the
defining properties of the Haldane phase survive in the small $t/J$ limit. The
large $t/J$ phase supports a gapped spin sector with similar properties
(ground-state degeneracy, edge state, and string order parameter) of the
Haldane chain, although the charge sector is gapless.


title: The existence and nature of the interstellar bow shock

abstract:
  We report a new diagnostic between two different states of the local
interstellar medium (LISM) near our solar system using a sensitivity study
constrained by several distinct and complementary observations of the LISM,
solar wind, and inner heliosphere. Assuming the Interstellar Boundary Explorer
(IBEX) He flow parameters for the LISM, we obtain a strength of $\sim
2.7\pm0.2$ $\mu$G and a direction pointing away from galactic coordinates $(28,
52)\pm 3^\circ$ for the interstellar magnetic field as resulting from fitting
Voyager 1 & 2 in situ plasma measurements and IBEX energetic neutral atoms
ribbon}. When using Ulysses parameters for the LISM He flow, we recently
reported the same direction but a strength of $2.2\pm0.1$ $\mu$G. First, we
notice that with Ulysses He flow, our solution is in the expected hydrogen
deflection plane (HDP). In contrast, for the IBEX He flow, the solution is
$\sim 20^{\circ}$ away from the corresponding HDP plane. Second, the long-term
monitoring of the interplanetary H I flow speed shows a value of $\sim 26$ km/s
measured at upwind from the Doppler-shift in the strong Lyman-$\alpha $ sky
background emission line. All elements of diagnostics seem therefore to support
Ulysses He flow parameters for the interstellar state. In that frame, we argue
that reliable discrimination between superfast, subfast, or superslow states of
the interstellar flow should be based on most existing in situ and remote
observations used together with global modelling of the heliosphere. For
commonly accepted LISM ionization rates, we show that a fast interstellar
bow-shock should be standing-off upstream of the heliopause.

categories: astro-ph.SR physics.comp-ph physics.flu-dyn physics.plasm-ph physics.space-ph


title: Long term observations of B2 1215+30 with VERITAS

abstract:
  We report on VERITAS observations of the BL Lac object B2 1215+30 between
2008 and 2012. During this period, the source was detected at very high
energies (VHE; E > 100 GeV) by VERITAS with a significance of $8.9\sigma$ and
showed clear variability on time scales larger than months. In 2011, the source
was found to be in a relatively bright state and a power-law fit to the
differential photon spectrum yields a spectral index of $3.6 \pm
0.4_{\mathrm{stat}} \pm 0.3_{\mathrm{syst}}$ with an integral flux above 200
GeV of $(8.0 \pm 0.9_{\mathrm{stat}} \pm 3.2_{\mathrm{syst}}) \times 10^{-12}\,
\mathrm{cm}^{-2} \mathrm{s}^{-1}$. No short term variability could be detected
during the bright state in 2011. Multi-wavelength data were obtained
contemporaneous with the VERITAS observations in 2011 and cover optical
(Super-LOTIS, MDM, Swift-UVOT), X-ray (Swift-XRT), and gamma-ray (Fermi-LAT)
frequencies. These were used to construct the spectral energy distribution
(SED) of B2 1215+30. A one-zone leptonic model is used to model the blazar
emission and the results are compared to those of MAGIC from early 2011 and
other VERITAS-detected blazars. The SED can be well reproduced with model
parameters typical for VHE-detected BL Lacs.


title: Doppler tomography of the circumstellar disk of {\pi} Aquarii

abstract:
  The work is aimed at a study of the circumstellar disk of the bright
classical binary Be star {\pi} Aqr. We analysed variations of a double-peaked
profile of the H{\alpha} emission line in the spectrum of {\pi} Aqr that was
observed in many phases during ~40 orbital cycles in 2004--2013. We applied the
Discrete Fourier Transform (DFT) method to search for periodicity in the peak
intensity (V/R) ratio. Doppler tomography was used to study the structure of
the disk around the primary. The dominant frequency in the power spectrum of
the H{\alpha} V/R ratio is 0.011873 day^-1 that correspond to a period of
84.2(2) days and is in agreement with the earlier determined orbital period of
the system, Porb=84.1 days. The V/R ratio shows a sinusoidal variation
phase-locked with the orbital period. Doppler maps of all our spectra show a
non-uniform structure of the disk around the primary: a ring with the inner and
outer radii at Vin~ 450 km/s and Vout~ 200km/s, respectively, along with an
extended stable region (spot) at V_x ~ 225 km/s and V_y~100 km/s. The disk
radius of ~ 65 Rsun = 0.33 AU was estimated assuming Keplerian motion of a
particle on a circular orbit at the disk outer edge.


title: Microscopic approach to coupled-channels effects on fusion

abstract:
  Background: Near-barrier fusion can be strongly affected by the coupling
between relative motion and internal degrees of freedom of the collision
partners. The time-dependent Hartree-Fock (TDHF) theory and the
coupled-channels (CC) method are standard approaches to investigate this aspect
of fusion dynamics. However, both approaches present limitations, such as a
lack of tunnelling of the many-body wave function in the former and a need for
external parameters to describe the nucleus-nucleus potential and the couplings
in the latter. Method: A method combining both approaches is proposed to
overcome these limitations. CC calculations are performed using two types of
inputs from Hartree-Fock (HF) theory: the nucleus-nucleus potential calculated
with the frozen HF method, and the properties of low-lying vibrational states
and giant resonances computed from the TDHF linear response. Results: The
effect of the couplings to vibrational modes is studied in the
$^{40}$Ca$+^{40}$Ca and $^{56}$Ni$+^{56}$Ni systems. This work demonstrates
that the main effect of these couplings is a lowering of the barrier, in good
agreement with the fusion thresholds predicted by TDHF calculations.
Conclusions: As the only phenomenological inputs are the choice of the internal
states of the nuclei and the parameters of the energy density functional used
in the HF and TDHF calculations, the method presented in this work has a broad
range of possible applications, including studies of alternative couplings or
reactions involving exotic nuclei.


title: Quiver Bialgebras and Monoidal Categories

abstract:
  We study the bialgebra structures on quiver coalgebras and the monoidal
structures on the categories of locally nilpotent and locally finite quiver
representations. It is shown that the path coalgebra of an arbitrary quiver
admits natural bialgebra structures. This endows the category of locally
nilpotent and locally finite representations of an arbitrary quiver with
natural monoidal structures from bialgebras. We also obtain theorems of Gabriel
type for pointed bialgebras and hereditary finite pointed monoidal categories.


title:
AxPUE: Application Level Metrics for Power Usage Effectiveness in Data
  Centers

abstract:
  The rapid growth of data volume brings big challenges to the data center
computing, and energy efficiency is one of the most concerned problems.
Researchers from various fields are now proposing solutions to green the data
center operations. Power usage effectiveness metric plays an important role in
the energy saving research. However, the exising usage effectiveness metrics
focus on measuring the relationship between the total facility energy consumed
and the IT equipment energy consumed, without reflecting the energy efficiency
of applications. In this paper, we analyze the requirements of
application-level metrics for power usage efficiency of the data centers, and
propose two novel energy efficiency metrics to provide strong guidance and
useful insight to data center design and optimization. We conduct comprehensive
experiments in the practical data centers using BigDataBench, a big data
benchmark suite, and the results demonstrate the rationality and efficiency of
AxPUE in measuring the actual computation energy consumption in data centers.


title: Stochastic Optimization Based Study of Dimerization Kinetics

abstract:
  We investigate the potential of numerical algorithms to decipher the kinetic
parameters involved in multi-step chemical reactions. To this end we study a
dimerization kinetics of protein as a model system. We follow the dimerization
kinetics using a stochastic simulation algorithm and combine it with three
different optimization techniques (Genetic Algorithm, Simulated Annealing and
Parallel Tempering) to obtain the rate constants involved in each reaction
step. We find good convergence of the numerical scheme to the rate constants of
the process. We also perform a sensitivity test on the reaction kinetic
parameters to see the relative effects of the parameters for the associated
profile of the monomer/dimer distribution.


title: Perturbatively improving renormalization constants

abstract:
  Renormalization factors relate the observables obtained on the lattice to
their measured counterparts in the continuum in a suitable renormalization
scheme. They have to be computed very precisely which requires a careful
treatment of lattice artifacts. In this work we present a method to suppress
these artifacts by subtracting one-loop contributions proportional to the
square of the lattice spacing calculated in lattice perturbation theory.


title: On almost everywhere convergence of tensor product spline projections

abstract:
  Let $d\in\mathbb N$ and $f$ be a function in the Orlicz class
$L(\log^+L)^{d-1}$ defined on the unit cube $[0,1]^d$ in $\mathbb{R}^d$. Given
partitions $\Delta_1,\ldots,$ $\Delta_d$ of $[0,1]$, we first prove that the
orthogonal projection $P_{(\Delta_1,\dots,\Delta_d)}(f)$ onto the space of
tensor product splines with arbitrary orders $(k_1,\dots, k_d)$ and knots
$\Delta_1,\ldots,\Delta_d$ converges to $f$ almost everywhere as the mesh
diameters $|\Delta_1|,\ldots, |\Delta_{d}|$ tend to zero. This extends the
one-dimensional result in [Passenbrunner and Shadrin, Journal of Approximation
Theory, 2014] to arbitrary dimensions.
  In a second step, we show that this result is optimal, i.e., given any
"bigger" Orlicz class $X=\sigma(L)L(\log^+ L)^{d-1}$ with an arbitrary function
$\sigma$ tending to zero at infinity, there exists a function $\varphi\in X$
and partitions of the unit cube such that the orthogonal projections of
$\varphi$ do not converge almost everywhere.


title: Heterodyne Spectroscopy of Polariton Spinor Interactions

abstract:
  We report on spinor polariton interactions in GaAs based microcavities. This
investigation is carried out by means of heterodyne polarized pump-probe
spectroscopy. We show the dependence of the energy renormalization of the lower
and upper polariton resonances with cavity detuning for different polariton
densities. We use the exciton-photon based Gross-Pitaevskii equation to model
the experiment for both lower and upper polariton modes. The theoretical
results reproduce qualitatively the experimental observations revealing the
magnitude and the sign of the parallel and anti-parallel spin interaction
strength. We evidence the strong influence of the biexciton resonance on the
anti-parallel spin polariton energy shift and provide the exciton-biexciton
coupling constant. We derive our results in the lower polariton basis using
Gross-Pitaevskii equation from which, we express analytically the spinor
polariton interactions and identify the clear role of the biexciton resonance.


title: A Bcool spectropolarimetric survey of over 150 solar-type stars

abstract:
  As part of the Bcool project, over 150 solar-type stars chosen mainly from
planet search databases have been observed between 2006 and 2013 using the
NARVAL and ESPaDOnS spectropolarimeters on the Telescope Bernard Lyot (Pic du
Midi, France) and the Canada France Hawaii Telescope (Mauna Kea, USA),
respectively. These single 'snapshot' observations have been used to detect the
presence of magnetic fields on 40% of our sample, with the highest detection
rates occurring for the youngest stars. From our observations we have
determined the mean surface longitudinal field (or an upper limit for stars
without detections) and the chromospheric surface fluxes, and find that the
upper envelope of the absolute value of the mean surface longitudinal field is
directly correlated to the chromospheric emission from the star and increases
with rotation rate and decreases with age.


title:
Tunneling and Relaxation of Single Quasiparticles in a
  Normal-Superconductor-Normal Single Electron Transistor

abstract:
  We investigate the properties of a hybrid single electron transistor,
involving a small superconducting island sandwiched between normal metal leads,
which is driven by dc plus ac voltages. In order to describe its properties we
derive from the microscopic theory a set of coupled equations. They consist of
a master equation for the probability to find excess charges on the island,
with rates depending on the distribution of non-equilibrium quasiparticles.
Their dynamics follows from a kinetic equation which accounts for the
excitation by single-electron tunneling as well as the relaxation and eventual
recombination due to the interaction with phonons. Our low-temperature results
compare well with recent experimental findings obtained for ac-driven hybrid
single-electron turnstiles.


title: Pre-main-sequence population in NGC 1893 region: X-ray properties

abstract:
  Continuing the attempt to understand the properties of the stellar content in
the young cluster NGC 1893 we have carried out a comprehensive multi-wavelength
study of the region. The present study focuses on the X-ray properties of
T-Tauri Stars (TTSs) in the NGC 1893 region. We found a correlation between the
X-ray luminosity, $L_X$, and the stellar mass (in the range 0.2$-$2.0 \msun) of
TTSs in the NGC 1893 region, similar to those reported in some other young
clusters, however the value of the power-law slope obtained in the present
study ($\sim$ 0.9) for NGC 1893 is smaller than those ($\sim$1.4 - 3.6)
reported in the case of TMC, ONC, IC 348 and Chameleon star forming regions.
However, the slope in the case of Class III sources (Weak line TTSs) is found
to be comparable to that reported in the case of NGC 6611 ($\sim$ 1.1). It is
found that the presence of circumstellar disks has no influence on the X-ray
emission. The X-ray luminosity for both CTTSs and WTTSs is found to decrease
systematically with age (in the range $\sim $ 0.4 Myr - 5 Myr). The decrease of
the X-ray luminosity of TTSs (slope $\sim$ -0.6) in the case of NGC 1893 seems
to be faster than observed in the case of other star-forming regions (slope
-0.2 to -0.5). There is indication that the sources having relatively large NIR
excess have relatively lower $L_X$ values. TTSs in NGC 1893 do not follow the
well established X-ray activity - rotation relation as in the case of
main-sequence stars.


title:
Topological instabilities in families of semilinear parabolic problems
  subject to nonlinear perturbations

abstract:
  In this article it is proved that the dynamical properties of a broad class
of semilinear parabolic problems are sensitive to arbitrarily small but smooth
perturbations of the nonlinear term, when the spatial dimension is either equal
to one or two. This topological instability is shown to result from a local
deformation of the global bifurcation diagram associated with the corresponding
elliptic problems. Such a deformation is shown to systematically occur via the
creation of either a multiple-point or a new fold-point on this diagram when an
appropriate small perturbation is applied to the nonlinear term. More
precisely, it is shown that for a broad class of nonlinear elliptic problems,
one can always find an arbitrary small perturbation of the nonlinear term, that
generates a local S on the bifurcation diagram whereas the latter is e.g.
monotone when no perturbation is applied; substituting thus a single solution
by several ones. Such an increase in the local multiplicity of the solutions to
the elliptic problem results then into a topological instability for the
corresponding parabolic problem.
  The rigorous proof of the latter instability result requires though to
revisit the classical concept of topological equivalence to encompass important
cases for the applications such as semi-linear parabolic problems for which the
semigroup may exhibit non-global dissipative properties, allowing for the
coexistence of blow-up regions and local attractors in the phase space; cases
that arise e.g. in combustion theory. A revised framework of topological
robustness is thus introduced in that respect within which the main topological
instability result is then proved for continuous, locally Lipschitz but not
necessarily $C^1$ nonlinear terms, that prevent in particular the use of
linearization techniques, and for which the family of semigroups may exhibit
non-dissipative properties.


title:
Simultaneous Information and Energy Transfer in Large-Scale Networks
  with/without Relaying

abstract:
  Energy harvesting (EH) from ambient radio-frequency (RF) electromagnetic
waves is an efficient solution for fully autonomous and sustainable
communication networks. Most of the related works presented in the literature
are based on specific (and small-scale) network structures, which although give
useful insights on the potential benefits of the RF-EH technology, cannot
characterize the performance of general networks. In this paper, we adopt a
large-scale approach of the RF-EH technology and we characterize the
performance of a network with random number of transmitter-receiver pairs by
using stochastic-geometry tools. Specifically, we analyze the outage
probability performance and the average harvested energy, when receivers employ
power splitting (PS) technique for "simultaneous" information and energy
transfer. A non-cooperative scheme, where information/energy are conveyed only
via direct links, is firstly considered and the outage performance of the
system as well as the average harvested energy are derived in closed form in
function of the power splitting. For this protocol, an interesting optimization
problem which minimizes the transmitted power under outage probability and
harvesting constraints, is formulated and solved in closed form. In addition,
we study a cooperative protocol where sources' transmissions are supported by a
random number of potential relays that are randomly distributed into the
network. In this case, information/energy can be received at each destination
via two independent and orthogonal paths (in case of relaying). We characterize
both performance metrics, when a selection combining scheme is applied at the
receivers and a single relay is randomly selected for cooperative diversity.


title: On local generators of affine distributions on Riemannian manifolds

abstract:
  Using a coordinate free characterization of hyperplanes intersection, we
provide explicitly a set of local generators for a smooth affine distribution
given by those smooth vector fields $X\in\mathfrak{X}(U)$ defined eventually on
an open subset $U\subseteq M$ of a smooth Riemannian manifold $(M,g)$, that
verifies the relations $g(X,X_1)=\dots =g(X,X_k)=0$, $g(X,Y_1)=h_1, \dots,
g(X,Y_p)=h_p$, where $X_1,\dots, X_k, Y_1, \dots, Y_p \in\mathfrak{X}(U)$, and
respectively $h_1,\dots, h_p \in \mathcal{C}^{\infty}(U,\mathbb{R})$, are
a-priori given quantities.
  In the case when $X_1,\dots, X_k, Y_1, \dots, Y_p$ are gradient vector fields
associated with some smooth functions $I_1,\dots, I_k, D_1, \dots, D_p \in
\mathcal{C}^{\infty}(U,\mathbb{R})$, i.e., $X_1 =\nabla_{g}I_1$, $\dots$, $X_k
= \nabla_{g}I_k$, $Y_1 = \nabla_{g}D_1$, $\dots, Y_p = \nabla_{g}D_p$, then we
obtain a set of local generators for the smooth affine distribution of smooth
vector fields which conserve the quantities $I_1, \dots, I_k$ and dissipate the
scalar quantities $D_1, \dots, D_p$ with prescribed rates $h_1, \dots, h_p$.


title: Some consequences of the Majoron being the dark radiation

abstract:
  We discuss some phenomenological consequences in a scenario where a singlet
Majoron plays the role of dark radiation. We study the interrelations between
neutrino mass generation and the scalar potential arising from this
identification. We find the extra scalar has to be light with a mass at or
below the GeV level. The mixing of this scalar with the Standard Model Higgs
impacts low energy phenomena such as the muonic hydrogen Lamb shift and muon
anomalous magnetic moment. Demanding that the light scalar solves the puzzle in
the muon magnetic moment requires the scalar to be lighter still with mass at
or below the 10 MeV level. The cross-sections for the production of heavy
neutrinos at LHC14 are also given.


title: O:H-O Bond Anomalous Relaxation Resolving Mpemba Paradox

abstract:
  We demonstrate that the Mpemba paradox arises intrinsically from the release
rate of energy initially stored in the covalent H-O part of the O:H-O bond in
water albeit experimental conditions. Generally, heating raises the energy of a
substance by lengthening and softening all bonds involved. However, the O:H
nonbond in water follows actively the general rule of thermal expansion and
drives the H-O covalent bond to relax oppositely in length and energy because
of the inter-electron-electron pair coupling [J Phys Chem Lett 4, 2565 (2013);
ibid 4, 3238 (2013)]. Heating stores energy into the H-O bond by shortening and
stiffening it. Cooling the water as the source in a refrigerator as a drain,
the H-O bond releases its energy at a rate that depends exponentially on the
initially storage of energy, and therefore, Mpemba effect happens. This effect
is formulated in terms of the relaxation time tau to represent all possible
processes of energy loss. Consistency between predictions and measurements
revealed that the tau drops exponentially intrinsically with the initial
temperature of the water being cooled.


title: Computational algebraic methods in efficient estimation

abstract:
  A strong link between information geometry and algebraic statistics is made
by investigating statistical manifolds which are algebraic varieties. In
particular it it shown how first and second order efficient estimators can be
constructed, such as bias corrected Maximum Likelihood and more general
estimators, and for which the estimating equations are purely algebraic. In
addition it is shown how Gr\"obner basis technology, which is at the heart of
algebraic statistics, can be used to reduce the degrees of the terms in the
estimating equations. This points the way to the feasible use, to find the
estimators, of special methods for solving polynomial equations, such as
homotopy continuation methods. Simple examples are given showing both equations
and computations. *** The proof of Theorem 2 was corrected by the latest
version. Some minor errors were also corrected.


title:
Simulating the Influence of Collaborative Networks on the Structure of
  Networks of Organizations, Employment Structure, and Organization Value

abstract:
  From the perspective of reindustrialization, it is important to understand
the evolution of the structure of the network of organizations employment
structure, and organization value. Understanding the potential influence of
collaborative networks (CNs) on these aspects may lead to the development of
appropriate economic policies. In this paper, we propose a theoretical approach
to analysis this potential influence, based on a model of dynamic networked
ecosystem of organizations encompassing collaboration relations among
organization, employment mobility, and organization value. A large number of
simulations has been performed to identify factors influencing the structure of
the network of organizations employment structure, and organization value. The
main findings are that 1) the higher the number of members of CNs, the better
the clustering and the shorter the average path length among organizations; 2)
the constitution of CNs does not affect neither the structure of the network of
organizations, nor the employment structure and the organization value.


title: Starspots on Young Solar-Type Stars

abstract:
  Doppler Imaging of starspots on young solar analogues is a way to investigate
the early history of solar magnetic activity by proxy. Doppler images of young
G-dwarfs have yielded the presence of large polar spots, extending to moderate
latitudes, along with measurements of the surface differential rotation. The
differential rotation measurement for one star (RX J0850.1- 7554) suggests it
is possibly the first example of a young G-type dwarf whose surface rotates as
almost a solid body, in marked contrast to the differential rotation of other
rapidly rotating young G-dwarfs and the present-day Sun. Overall, our Doppler
imaging results show that the young Sun possessed a fundamentally different
dynamo to today.


title: Boosting an analogue of Jordan's theorem for finite groups

abstract:
  Let $\mathcal C$ be a set of finite groups which is closed under taking
subgroups and let $d$ and $M$ be positive integers. Suppose that for any
$G\in\mathcal C$ whose order is divisible by at most two distinct primes there
exists an abelian subgroup $A\subseteq G$ such that $A$ is generated by at most
$d$ elements and $[G : A] \le M$. We prove that there exists a positive
constant $C_0$ such that any $G \in \mathcal C$ has an abelian subgroup $A$
satisfying $[G : A] \le C_0$, and $A$ can be generated by at most $d$ elements.
We also prove some related results. Our proofs use the Classification of Finite
Simple Groups.


title:
One-dimensional disordered quantum mechanics and Sinai diffusion with
  random absorbers

abstract:
  We study the one-dimensional Schr\"odinger equation with a disordered
potential of the form $V (x) = \phi(x)^2+\phi'(x) + \kappa(x) $ where $\phi(x)$
is a Gaussian white noise with mean $\mu g$ and variance $g$, and $\kappa(x)$
is a random superposition of delta functions distributed uniformly on the real
line with mean density $\rho$ and mean strength $v$. Our study is motivated by
the close connection between this problem and classical diffusion in a random
environment (the Sinai problem) in the presence of random absorbers~: $\phi(x)$
models the force field acting on the diffusing particle and $\kappa(x)$ models
the absorption properties of the medium in which the diffusion takes place. The
focus is on the calculation of the complex Lyapunov exponent $ \Omega(E) =
\gamma(E) - \mathrm{i} \pi N(E) $, where $N$ is the integrated density of
states per unit length and $\gamma$ the reciprocal of the localisation length.
By using the continuous version of the Dyson-Schmidt method, we find an exact
formula, in terms of a Hankel function, in the particular case where the
strength of the delta functions is exponentially-distributed with mean $v=2g$.
Building on this result, we then solve the general case -- in the low-energy
limit -- in terms of an infinite sum of Hankel functions. Our main result,
valid without restrictions on the parameters of the model, is that the
integrated density of states exhibits the power law behaviour
  $$ N(E) \underset{E\to0+}{\sim} E^\nu \hspace{0.5cm} \mbox{where }
\nu=\sqrt{\mu^2+2\rho/g}\:. $$
  This confirms and extends several results obtained previously by approximate
methods.


title:
Taylor- and fugacity expansion for the effective center model of QCD at
  finite density

abstract:
  Using the effective center model of QCD we test series expansions for finite
chemical potential $\mu$. In particular we study two variants of Taylor
expansion as well as the fugacity series. The effective center model has a dual
representation where the sign problem is absent and reliable Monte Carlo
simulations are possible at arbitrary $\mu$. We use the results from the dual
simulation as reference data to assess the Taylor- and fugacity series
approaches. We find that for most of parameter space fugacity expansion is the
best (but also numerically most expensive) choice for reproducing the dual
simulation results, while conventional Taylor expansion is reliable only for
very small $\mu$. We also discuss the results of a modified Taylor expansion in
$e^{\pm \mu} - 1 $ which at the same numerical effort clearly outperforms the
conventional Taylor series.


title:
Projective normality of toric 3-folds with non-big adjoint hyperplane
  sections, II

abstract:
  Let $(X, A)$ be a nonsingular polarized toric 3-fold. We show that if the
adjoint bundle of $A$ has no glabal section, then all ample line bundles on $X$
are normally generated. Even if the adjoint bundle is effective, if it is not
big, then it is shown the normal generation. In particular, we show that all
ample line bundles on a nonsingular toric Fano 3-fold are normally generated.


title:
Measuring the universal synchronization properties of coupled
  oscillators across the Hopf instability

abstract:
  When a driven oscillator loses phase-locking to a master oscillator via a
Hopf bifurcation, it enters a bounded-phase regime in which its average
frequency is still equal to the master frequency, but its phase displays
temporal oscillations. Here we characterize these two synchronization regimes
in a laser experiment, by measuring the spectrum of the phase fluctuations
across the bifurcation. We find experimentally, and confirm numerically, that
the low frequency phase noise of the driven oscillator is strongly suppressed
in both regimes in the same way. Thus the long-term phase stability of the
master oscillator is transferred to the driven one, even in the absence of
phase-locking. The numerical study of a generic, minimal model suggests that
such behavior is universal for any periodically driven oscillator near a Hopf
bifurcation point.


title:
The global existence theorem for quasi-linear wave equations with
  multiple speeds, II

abstract:
  The Cauchy problem is studied for systems of quasi-linear wave equations with
multiple speeds in two space dimensions. Using the method of Klainerman and
Sideris together with the localized energy estimate, we give an alternative
proof of a beautiful result of Hoshiga and Kubo.


title: Some hard families of parameterised counting problems

abstract:
  We consider parameterised subgraph-counting problems of the following form:
given a graph G, how many k-tuples of its vertices have a given property? A
number of such problems are known to be #W[1]-complete; here we substantially
generalise some of these existing results by proving hardness for two large
families of such problems. We demonstrate that it is #W[1]-hard to count the
number of k-vertex subgraphs having any property where the number of distinct
edge-densities of labelled subgraphs that satisfy the property is o(k^2). In
the special case that the property in question depends only on the number of
edges in the subgraph, we give a strengthening of this result which leads to
our second family of hard problems.


title:
Weyl's law for Hecke operators on GL(n) over imaginary quadratic number
  fields

abstract:
  We prove a mean value theorem for the traces of Hecke operators acting on
cusp forms of GL(n) over imaginary quadratic number fields together with an
upper bound for the error term depending explicitly on the Hecke operator.


title: Exact simulation pricing with Gamma processes and their extensions

abstract:
  Exact path simulation of the underlying state variable is of great practical
importance in simulating prices of financial derivatives or their sensitivities
when there are no analytical solutions for their pricing formulas. However, in
general, the complex dependence structure inherent in most nontrivial
stochastic volatility (SV) models makes exact simulation difficult. In this
paper, we present a nontrivial SV model that parallels the notable Heston SV
model in the sense of admitting exact path simulation as studied by Broadie and
Kaya. The instantaneous volatility process of the proposed model is driven by a
Gamma process. Extensions to the model including superposition of independent
instantaneous volatility processes are studied. Numerical results show that the
proposed model outperforms the Heston model and two other L\'evy driven SV
models in terms of model fit to the real option data. The ability to exactly
simulate some of the path-dependent derivative prices is emphasized. Moreover,
this is the first instance where an infinite-activity volatility process can be
applied exactly in such pricing contexts.


title:
Measurement of the mass difference between top and anti-top quarks in pp
  collisions at sqrt(s) = 7 TeV using the ATLAS detector

abstract:
  A measurement of the mass difference between top and anti-top quarks is
presented. In a 4.7 fb-1 data sample of proton--proton collisions at sqrt(s) =
7 TeV recorded with the ATLAS detector at the LHC, events consistent with ttbar
production and decay into a single charged lepton final state are
reconstructed. For each event, the mass difference between the top and anti-top
quark candidate is calculated. A two b-tag requirement is used in order to
reduce the background contribution. A maximum likelihood fit to these per-event
mass differences yields mt-mtbar = 0.67 +/- 0.61 (stat) +/- 0.41 (syst) GeV,
consistent with CPT invariance.


title:
Degree-degree dependencies in directed networks with heavy-tailed
  degrees

abstract:
  In network theory, Pearson's correlation coefficients are most commonly used
to measure the degree assortativity of a network. We investigate the behavior
of these coefficients in the setting of directed networks with heavy-tailed
degree sequences. We prove that for graphs where the in- and out-degree
sequences satisfy a power law with realistic parameters, Pearson's correlation
coefficients converge to a non-negative number in the infinite network size
limit. We propose alternative measures for degree-degree dependencies in
directed networks based on Spearman's rho and Kendall's tau. Using examples and
calculations on the Wikipedia graphs for nine different languages, we show why
these rank correlation measures are more suited for measuring degree
assortativity in directed graphs with heavy-tailed degrees.


title: The graphs with all but two eigenvalues equal to $\pm 1$

abstract:
  We determine all graphs whose adjacency matrix has at most two eigenvalues
(multiplicities included) different from $\pm 1$ and decide which of these
graphs are determined by their spectrum. This includes the so-called friendship
graphs, which consist of a number of edge-disjoint triangles meeting in one
vertex. It turns out that the friendship graph is determined by its spectrum,
except when the number of triangles equals sixteen.


title:
Interplay of Kondo effect and strong spin-orbit coupling in multi-hole
  ultraclean carbon nanotubes

abstract:
  We report on cotunneling spectroscopy magnetoconductance measurements of
multi-hole ultraclean carbon nanotube quantum dots in the SU(4) Kondo regime
with strong spin-orbit coupling. Successive shells show a gradual weakening of
the Kondo effect with respect to the spin-orbital splittings, leading to an
evolution from SU(4) to SU(2) symmetry with a suppressed conductance at half
shell filling. The extracted energy level spectrum, overally consistent with
negligible disorder in the nanotube, shows in the half filled case large
renormalizations due to Coulombian effects.


title: Rigorous numerics for NLS: bound states, spectra, and controllability

abstract:
  In this paper it is demonstrated how rigorous numerics may be applied to the
one-dimensional nonlinear Schr\"odinger equation (NLS); specifically, to
determining bound--state solutions and establishing certain spectral properties
of the linearization. Since the results are rigorous, they can be used to
complete a recent analytical proof [6] of the local exact controllability of
NLS.


title: Two-dimensional families of hyperelliptic jacobians with big monodromy

abstract:
  Let $K$ be a global field of characteristic different from 2 and $u(x)\in
K[x]$ be an irreducible polynomial of even degree $2g\ge 6$, whose Galois group
over $K$ is either the full symmetric group $S_{2g}$ or the alternating group
$A_{2g}$. We describe explicitly how to choose (infinitely many) pairs of
distinct elements $t_1, t_2$ of $K$ such that the $g$-dimensional jacobian of a
hyperelliptic curve $y^2=(x-t_1)(x-t_2))u(x)$ has no nontrivial endomorphisms
over an algebraic closure of $K$ and has big $\ell$-adic monodromy.


title:
Activation cross-sections of deuteron induced reactions on natGd up to
  50 MeV

abstract:
  Activation cross-sections are presented for the first time for
natGd(d,xn)161,160,156(m+), 154,154m1,154m2,153,152(m+),151(m+)Tb,
natGd(d,x)159,153,151Gd and natGd(d,x)156Eu reactions from their respective
thresholds up to 50 MeV. The cross-sections were measured by the stacked-foil
irradiation technique and by using high resolution gamma-ray spectrometry. The
measured values were compared with the results of theoretical models calculated
by the computer codes ALICE-D, EMPIRE-D and TALYS (data from TENDL library).
Integral yields of the reaction products were deduced from the excitation
functions.


title:
A remark on perimeter-diameter and perimeter-circumradius inequalities
  under lattice constraints

abstract:
  In this note, we study several inequalities involving geometric functionals
for lattice point-free planar convex sets. We focus on the previously not
addressed cases perimeter--diameter and perimeter--circumradius.


title:
Common Envelope Mechanisms: Constraints from the X-ray Luminosity
  Function of High Mass X-ray Binaries

abstract:
  We use the measured X-ray luminosity function (XLF) of high-mass X-ray
binaries (HMXBs) in nearby star-forming galaxies to constrain the common
envelope (CE) mechanisms, which play a key role in governing the binary
evolution. We find that the XLF can be reproduced quite closely under both CE
mechanisms usually adopted, i.e., the $\alpha_{\rm CE}$ formalism and the
$\gamma$ algorithm, with a reasonable range of parameters considered. Provided
that the parameter combination is the same, the $\gamma$ algorithm is likely to
produce more HMXBs than the $\alpha_{\rm CE}$ formalism, by a factor of up to
$\sim$ 10. In the framework of the $\alpha_{\rm CE}$ formalism, a high value of
$\alpha_{\rm CE}$ is required to fit the observed XLF, though it does not
significantly affect the global number of the HMXB populations. We present the
detailed components of the HMXB populations under the $\gamma$ algorithm and
compare them with those in Zuo et al. and observations. We suggest the distinct
observational properties, as well as period distributions of HMXBs, may provide
further clues to discriminate between these two types of CE mechanisms.


title:
Randomized co-training: from cortical neurons to machine learning and
  back again

abstract:
  Despite its size and complexity, the human cortex exhibits striking
anatomical regularities, suggesting there may simple meta-algorithms underlying
cortical learning and computation. We expect such meta-algorithms to be of
interest since they need to operate quickly, scalably and effectively with
little-to-no specialized assumptions.
  This note focuses on a specific question: How can neurons use vast quantities
of unlabeled data to speed up learning from the comparatively rare labels
provided by reward systems? As a partial answer, we propose randomized
co-training as a biologically plausible meta-algorithm satisfying the above
requirements. As evidence, we describe a biologically-inspired algorithm,
Correlated Nystrom Views (XNV) that achieves state-of-the-art performance in
semi-supervised learning, and sketch work in progress on a neuronal
implementation.


title: Stabilizing entanglement in the presence of local decay processes

abstract:
  We investigate to what extent a suitably chosen system Hamiltonian can
counteract local dissipative processes and preserve entanglement in the
stationary state. The results determine prospects and limitations of
dissipative state preparation schemes based on natural dissipative processes --
in contrast to engineered, typically non-local dissipative schemes. As an
exemplary case, we determine the stationary state of two spontaneously decaying
two-level systems with optimal entanglement properties. The corresponding
system Hamiltonian is derived, and its possible experimental implementation is
discussed in detail. Finally, we discuss generalizations for many qubits.


title:
Vibrationally Resolved Decay Width of Interatomic Coulombic Decay in
  HeNe

abstract:
  We investigate the ionization of HeNe from below the He 1s3p excitation to
the He ionization threshold. We observe HeNe$^+$ ions with an enhancement by
more than a factor of 60 when the He side couples resonantly to the radiation
field. These ions are an experimental proof of a two-center resonant
photoionization mechanism predicted by Najjari et al. [Phys. Rev. Lett. 105,
153002 (2010)]. Furthermore, our data provide electronic and vibrational state
resolved decay widths of interatomic Coulombic decay (ICD) in HeNe dimers. We
find that the ICD lifetime strongly increases with increasing vibrational
state.


title: 3-filiform Leibniz algebras of maximum length

abstract:
  This work completes the study of the solvable Leibniz algebras, more
precisely, it completes the classification of the $3$-filiform Leibniz algebras
of maximum length \cite{3-filiform}. Moreover, due to the good structure of the
algebras of maximum length, we also tackle some of their cohomological
properties. Our main tools are the previous result of Cabezas and Pastor
\cite{Pastor}, the construction of appropriate homogeneous basis in the
considered connected gradation and the computational support provided by the
two programs implemented in the software \textit{Mathematica}.


title:
A higher-order spatial FDTD scheme with CFS PML for 3D numerical
  simulation of wave propagation in cold plasma

abstract:
  A novel 3-D higher-order finite-difference time-domain framework with complex
frequency-shifted perfectly matched layer for the modeling of wave propagation
in cold plasma is presented. Second- and fourth-order spatial approximations
are used to discretize Maxwell's curl equations and a uniaxial perfectly
matched layer with the complex frequency-shifted equations is introduced to
terminate the computational domain. A numerical dispersion study of second- and
higher-order techniques is elaborated and their stability criteria are
extracted for each scheme. Comparisons with analytical solutions verify the
accuracy of the proposed methods and the low dispersion error of the
higher-order schemes.


title: Einstein's 1916 derivation of the Field Equations

abstract:
  In his first November 4, 1915 paper Einstein wrote the Lagrangian form of his
field equations. In the fourth November 25, 1915 paper, Einstein added a trace
term of the energy-momentum tensor on the right-hand side of the generally
covariant field equations. The main purpose of the present work is to show that
in November 4, 1915, Einstein had already explored much of the main ingredients
that were required for the formulation of the final form of the field equations
of November 25, 1915. The present work suggests that the idea of adding the
second-term on the right-hand side of the field equation might have originated
in reconsideration of the November 4, 1915 field equations. In this regard, the
final form of Einstein's field equations with the trace term may be linked with
his work of November 4, 1915. The interesting history of the derivation of the
final form of the field equations is inspired by the exchange of letters
between Einstein and Paul Ehrenfest in winter 1916 and by Einstein's 1916
derivation of the November 25, 1915 field equations.


title:
SensorCloud: Towards the Interdisciplinary Development of a Trustworthy
  Platform for Globally Interconnected Sensors and Actuators

abstract:
  Although Cloud Computing promises to lower IT costs and increase users'
productivity in everyday life, the unattractive aspect of this new technology
is that the user no longer owns all the devices which process personal data. To
lower scepticism, the project SensorCloud investigates techniques to understand
and compensate these adoption barriers in a scenario consisting of cloud
applications that utilize sensors and actuators placed in private places. This
work provides an interdisciplinary overview of the social and technical core
research challenges for the trustworthy integration of sensor and actuator
devices with the Cloud Computing paradigm. Most importantly, these challenges
include i) ease of development, ii) security and privacy, and iii) social
dimensions of a cloud-based system which integrates into private life. When
these challenges are tackled in the development of future cloud systems, the
attractiveness of new use cases in a sensor-enabled world will considerably be
increased for users who currently do not trust the Cloud.


title:
A census of 4-valent half-arc-transitive graphs and arc-transitive
  digraphs of valence two

abstract:
  A complete list of all connected arc-transitive asymmetric digraphs of
in-valence and out-valence 2 on up to 1000 vertices is presented. As a
byproduct, a complete list of all connected 4-valent graphs admitting a
half-arc-transitive group of automorphisms on up to 1000 vertices is obtained.
Several graph-theoretical properties of the elements of our census are
calculated and discussed.


title:
Systematic Uncertainties at the T2K Experiment for Oscillation
  Measurements

abstract:
  The T2K experiment is a long-baseline neutrino oscillation experiment with
the ability to measure precisely $\nu_{\mu}\rightarrow\nu_e$ and
$\nu_{\mu}\rightarrow\nu_{\mu}$ oscillations. Control of systematic
uncertainties-dominated by flux and cross section uncertainties-is critical for
the precision of these measurements. An analysis of charged current $\nu_{\mu}$
interactions at the T2K near detector significantly reduces these
uncertainties, from 26.9% to 3.0% for the current $\nu_{\mu}\rightarrow\nu_e$
measurement at T2K.


title:
Vertex dynamics in multi-soliton solutions of Kadomtsev-Petviashvili II
  equation

abstract:
  A functional of the solution of the Kadomtsev-Petviashvili II equation maps
multi-soliton solutions onto systems of vertices - structures that are
localized around soliton junctions. A solution with one junction is mapped onto
a single vertex, which emulates a free, spatially extended, particle. In
solutions with several junctions, each junction is mapped onto a vertex. Moving
in the x-y plane, the vertices collide, coalesce upon collision, and then split
up. When well separated, they emulate free particles. Multi-soliton solutions,
whose structure does not change under space-time inversion as for infinite
times, are mapped onto vertex systems that undergo elastic collisions.
Solutions, whose structure does change, are mapped onto systems that undergo
inelastic collisions. The inelastic vertex collisions generated from the
infinite family of (M,1) solutions (M external solitons, (M-2) Y-shaped soliton
junctions, M greater than 3) play a unique role: The only definition of vertex
mass consistent with momentum conservation in these collisions is the spatial
integral of the vertex profile. This definition ensures, in addition, that, in
these collisions, the total mass and kinetic energy due to the motion in the
y-direction are conserved. In general, the kinetic energy due to the motion in
the x-direction is not conserved in these collisions.


title: The Implications from Benchmarking Three Big Data Systems

abstract:
  Along with today's data explosion and application diversification, a variety
of hardware platforms for big data are emerging, attracting interests from both
industry and academia. The existing hardware platforms represent a wide range
of implementation approaches, and different hardware platforms have different
strengths. In this paper, we conduct comprehensive evaluations on three
representative big data systems: Intel Xeon, Atom (low power processors), and
many-core Tilera using BigDataBench - a big data benchmark suite. Then we
explore the relative performance of the three implementation approaches by
running BigDataBench, and provide strong guidance for the big data systems
construction. Through our experiments, we have inferred that a big data system
based on specific hardware has different performance in the context of
different applications and data volumes. When we construct a system, we should
take into account not only the performance or energy consumption of the pure
hardware, but also the characteristics of applications running on them. Data
scale, application type and complexity should be considered comprehensively
when researchers or architects plan to choose fundamental components for their
big data systems.


title: Sparse Predictive Structure of Deconvolved Functional Brain Networks

abstract:
  The functional and structural representation of the brain as a complex
network is marked by the fact that the comparison of noisy and intrinsically
correlated high-dimensional structures between experimental conditions or
groups shuns typical mass univariate methods. Furthermore most network
estimation methods cannot distinguish between real and spurious correlation
arising from the convolution due to nodes' interaction, which thus introduces
additional noise in the data. We propose a machine learning pipeline aimed at
identifying multivariate differences between brain networks associated to
different experimental conditions. The pipeline (1) leverages the deconvolved
individual contribution of each edge and (2) maps the task into a sparse
classification problem in order to construct the associated "sparse deconvolved
predictive network", i.e., a graph with the same nodes of those compared but
whose edge weights are defined by their relevance for out of sample predictions
in classification. We present an application of the proposed method by decoding
the covert attention direction (left or right) based on the single-trial
functional connectivity matrix extracted from high-frequency
magnetoencephalography (MEG) data. Our results demonstrate how network
deconvolution matched with sparse classification methods outperforms typical
approaches for MEG decoding.


title: Finite subgroups of diffeomorphism groups

abstract:
  We prove:(1) the existence, for every integer n > 3, of a noncompact smooth
n-dimensional topological manifold whose diffeomorphism group contains an
isomorphic copy of every finitely presented group; (2) a finiteness theorem on
finite simple subgroups of diffeomorphism groups of compact smooth topological
manifolds.


title:
Two-point gauge invariant quark Green's functions with polygonal phase
  factor lines

abstract:
  Polygonal lines are used for the paths of the gluon field phase factors
entering in the definition of gauge invariant quark Green's functions. This
allows classification of the Green's functions according to the number of
segments the polygonal lines contain. Functional relations are established
between Green's functions with polygonal lines with different numbers of
segments. An integrodifferential equation is obtained for the quark two-point
Green's function with a path along a single straight line segment where the
kernels are represented by a series of Wilson loop averages along polygonal
contours. The equation is exactly and analytically solved in the case of
two-dimensional QCD in the large-$N_c$ limit. The solution displays generation
of an infinite number of dynamical quark masses accompanied with branch point
singularities that are stronger than simple poles. An approximation scheme,
based on the counting of functional derivatives of Wilson loops, is proposed
for the resolution of the equation in four dimensions.


title: Efficiency of the Wang-Landau algorithm: a simple test case

abstract:
  We analyze the efficiency of the Wang-Landau algorithm to sample a multimodal
distribution on a prototypical simple test case. We show that the exit time
from a metastable state is much smaller for the Wang Landau dynamics than for
the original standard Metropolis-Hastings algorithm, in some asymptotic regime.
Our results are confirmed by numerical experiments on a more realistic test
case.


title:
Study of Baryon Resonances in the Photoproduction gamma p ---> K*
  Sigma(1190)

abstract:
  In this talk, we report the theoretical studies of baryon resonances for the
gamma p ---> K*0 Sigma+ and gamma p ---> K*+ Sigma0 reaction processes by
making use of the effective Lagrangian method in the tree-level Born
approximation. The numerical results for the total and differential cross
sections are shown with the presently available data. It turns out that the
contributions from the N* and Delta* resonances are almost negligible near the
threshold energy. On the other hand, the effects of the K exchange in the t
channel and Delta(1232) in the s channel are considerably larger than other
ones in the scattering process, being in good agreement with the experimental
data.


title: Screening of electron-phonon coupling in graphene on Ir(111)

abstract:
  The phonon dispersion of graphene on Ir(111) has been determined by means of
angle-resolved inelastic electron scattering and density functional
calculations. Kohn anomalies of the highest optical-phonon branches are
observed at the $\Gamma$ and K point of the surface Brillouin zone. At K the
Kohn anomaly is weaker than observed from pristine graphene and graphite. This
observation is rationalized in terms of a decrease of the electron-phonon
coupling due to screening of graphene electron correlations by the metal
substrate.


title: A single photon transistor based on superconducting systems

abstract:
  We present a realistic scheme for how to construct a single-photon transistor
where the presence or absence of a single microwave photon controls the
propagation of a subsequent strong signal signal field. The proposal is
designed to work with existing superconducting artificial atoms coupled to
cavities. We study analytically and numerically the efficiency and the gain of
our proposal and show that current transmon qubits allow for error
probabilities ~1% and gains of the order of hundreds.


title:
A maximally superintegrable deformation of the N-dimensional quantum
  Kepler-Coulomb system

abstract:
  The $N$-dimensional quantum Hamiltonian $ \hat{H} = -\frac{\hbar^2
{|\mathbf{q} } | }{2(\eta +| {\mathbf{q}} |)} {\mathbf{\nabla}}^2 -
\frac{k}{\eta + |{\mathbf{q}} |} $ is shown to be exactly solvable for any real
positive value of the parameter $\eta$. Algebraically, this Hamiltonian system
can be regarded as a new maximally superintegrable $\eta$-deformation of the
$N$-dimensional Kepler-Coulomb Hamiltonian while, from a geometric viewpoint,
this superintegrable Hamiltonian can be interpreted as a system on an
$N$-dimensional Riemannian space with nonconstant curvature. The eigenvalues
and eigenfunctions of the model are explicitly obtained, and the spectrum
presents a hydrogen-like shape for positive values of the deformation parameter
$\eta$ and of the coupling constant $k$.


title: Web Annotation as a First Class Object

abstract:
  Scholars have made handwritten notes and comments in books and manuscripts
for centuries. Today's blogs and news sites typically invite users to express
their opinions on the published content; URLs allow web resources to be shared
with accompanying annotations and comments using third-party services like
Twitter or Facebook. These contributions have until recently been constrained
within specific services, making them second-class citizens of the Web.
  Web Annotations are now emerging as fully independent Linked Data in their
own right, no longer restricted to plain textual comments in application silos.
Annotations can now range from bookmarks and comments, to fine-grained
annotations of a selection of, for example, a section of a frame within a video
stream. Technologies and standards now exist to create, publish, syndicate,
mash-up and consume, finely targeted, semantically rich digital annotations on
practically any content, as first-class Web citizens. This development is being
driven by the need for collaboration and annotation reuse amongst domain
researchers, computer scientists, scientific publishers, and scholarly content
databases.


title:
Energy metabolism and glutamate-glutamine cycle in the brain: a
  stoichiometric modeling perspective

abstract:
  The energetics of cerebral activity critically relies on the functional and
metabolic interactions between neurons and astrocytes. Important open questions
include the relation between neuronal versus astrocytic energy demand, glucose
uptake and intercellular lactate transfer, as well as their dependence on the
level of activity. We have developed a large-scale, constraint-based network
model of the metabolic partnership between astrocytes and glutamatergic neurons
that allows for a quantitative appraisal of the extent to which stoichiometry
alone drives the energetics of the system. We find that the velocity of the
glutamate-glutamine cycle ($V_{cyc}$) explains part of the uncoupling between
glucose and oxygen utilization at increasing $V_{cyc}$ levels. Thus, we are
able to characterize different activation states in terms of the tissue
oxygen-glucose index (OGI). Calculations show that glucose is taken up and
metabolized according to cellular energy requirements, and that partitioning of
the sugar between different cell types is not significantly affected by
$V_{cyc}$. Furthermore, both the direction and magnitude of the lactate shuttle
between neurons and astrocytes turn out to depend on the relative cell glucose
uptake while being roughly independent of $V_{cyc}$. These findings suggest
that, in absence of ad hoc activity-related constraints on neuronal and
astrocytic metabolism, the glutamate-glutamine cycle does not control the
relative energy demand of neurons and astrocytes, and hence their glucose
uptake and lactate exchange.


title: The occultation of Arcturus in the Vatican

abstract:
  The dome of Saint Peter's Basilica plays the role of the Moon during a
stellar occultation and Arcturus is the target star. This occultation-like
phenomenon is useful for introducing to occultation astronomy a class of
student up to university level. It can be organized very easily at the
convenience of the audience. Techical and didactical aspects are discussed; the
video is available at http://www.youtube.com/watch?v=hIfsj7t-u-c and has been
realized with an ordinary camcorder.


title: Simulating Zeno physics by quantum quench with superconducting circuits

abstract:
  Studying out-of-equilibrium physics in quantum systems under quantum quench
is of vast experimental and theoretical interests. Using periodic quantum
quenches, we present an experimentally accessible scheme to simulate the
quantum Zeno and anti-Zeno effects in an open quantum system of a single
superconducting qubit interacting with an array of transmission line
resonators. The scheme is based on the following two observations: Firstly,
compared with conventional systems, the short-time non-exponential decay in our
superconducting circuit system is readily observed; and secondly, a quench-off
process mimics an ideal projective measurement when its time duration is
sufficiently long. Our results show the active role of quantum quench in
quantum simulation and control.


title:
Transverse shift of a beam with orbital angular momentum under
  reflection from a dielectric film

abstract:
  We present the results of numerical analysis of Gauss-Bessel beam reflection
from a dielectric film under different angles of incidence. A transverse shift
of the beam under the orbital momentum sign change is observed. The value of
the shift is independent of the polarization state of the incident beam.


title: Translation invariant time-dependent solutions to massive gravity

abstract:
  Homogeneous time-dependent solutions of massive gravity generalise the plane
wave solutions of the linearised Fierz-Pauli equations for a massive spin-two
particle, as well as the Kasner solutions of General Relativity. We show that
they also allow a clear counting of the degrees of freedom and represent a
simplified framework to work out the constraints, the equations of motion and
the initial value formulation. We work in the vielbein formulation of massive
gravity, find the phase space resulting from the constraints and show that
several disconnected sectors of solutions exist some of which are unstable. The
initial values determine the sector to which a solution belongs. Classically,
the theory is not pathological but quantum mechanically the theory may suffer
from instabilities. The latter are not due to an extra ghost-like degree of
freedom.


title:
A study of obliquely propagating longitudinal shear waves in a periodic
  laminate

abstract:
  The basic purpose of this work is to demonstrate, by quite simple and
explicit calculation, the possibility that a simple laminate composed of
ordinary materials can display the kind of response associated with a
"metamaterial". Specifically, a wave of Floquet--Bloch type is analyzed, taking
careful account of the requirements of causality and passivity. Then, the
generation of such a wave by transmission, from ordinary homogeneous material,
into a half-space composed of the laminate is considered. As is well-known for
any dispersive material, phase velocity is distinct from group velocity, and
information is carried by the latter. Thus, in line with the discussion of
photonic crystals by Notomi [1], refraction is considered in terms of the group
velocity. Negative refraction appears never to occur, if the interface between
ordinary material and composite is parallel to the interfaces in the composite
but negative refraction is possible, over an appreciable frequency range, if
the interface between ordinary material and composite is orthogonal to the
interface in the composite.


title: Spatial averaging and a non-Gaussianity

abstract:
  The spatial averaging used for the splitting of the local scale factor on the
homogeneous background and small inhomogeneous perturbation leads to a
non-local relationship between locally and globally defined comoving curvature
perturbations. We study this relationship within a quasi-homogeneous, nearly
spatially flat domain of the Universe. It is shown that, on scales larger than
the size of the observed patch, the Fourier components of the locally defined
comoving curvature perturbation are suppressed. We have also shown that the
statistical properties of local and global comoving curvature perturbations are
coincide on a small scale. Several examples are discussed in detail.


title: SU(12) Kondo Effect in Carbon Nanotube Quantum Dot

abstract:
  We study the Kondo effect in a CNT(left lead)-CNT(QD)-CNT(right lead)
structure. Here CNT is a single-wall metallic carbon nanotube, for which 1) the
valence and conduction bands of electrons with zero orbital angular momentum
($m=0$) coalesc at the two valley points ${\bf{K}}$ and ${\bf{K}}'$ of the
first Brillouin zone and 2) the energy spectrum of electrons with $m \ne 0$ has
a gap whose size is proportional to $|m|$. Following adsorption of hydrogen
atoms and application of an appropriately designed gate potential, electron
energy levels in the CNT(QD) are tunable to have: 1) two-fold spin degeneracy;
2) two-fold isospin (valley) degeneracy; 3) three-fold orbital degeneracy
$m=0,\pm1$. As a result, an SU(12) Kondo effect is realized with remarkably
high Kondo temperature. Unlike the SU(2) case, the low temperature conductance
and magnetic susceptibility have a peak at finite temperature. Moreover, the
magnetic susceptibilities for parallel and perpendicular magnetic fields (WRT
the tube axis) display anisotropy with a universal ratio
$\chi_{\rm{imp}}^\parallel / \chi_{\rm{imp}}^\perp=\eta$ that depends only on
the electron's orbital and spin $g$ factors.


title:
Identifying Potential Risks and Benefits of Using Cloud in Distributed
  Software Development

abstract:
  Cloud-based infrastructure has been increasingly adopted by the industry in
distributed software development (DSD) environments. Its proponents claim that
its several benefits include reduced cost, increased speed and greater
productivity in software development. Empirical evaluations, however, are in
the nascent stage of examining both the benefits and the risks of cloud-based
infrastructure. The objective of this paper is to identify potential benefits
and risks of using cloud in a DSD project conducted by teams based in Helsinki
and Madrid. A cross-case qualitative analysis is performed based on focus
groups conducted at the Helsinki and Madrid sites. Participants' observations
are used to supplement the analysis. The results of the analysis indicated that
the main benefits of using cloud are rapid development, continuous integration,
cost savings, code sharing, and faster ramp-up. The key risks determined by the
project are dependencies, unavailability of access to the cloud, code
commitment and integration, technical debt, and additional support costs. The
results revealed that if such environments are not planned and set up
carefully, the benefits of using cloud in DSD projects might be overshadowed by
the risks associated with it.


title: Finite group actions on manifolds without odd cohomology

abstract:
  Let $X$ be a compact smooth manifold, possibly with boundary. Denote by
$X_1,\dots,X_r$ the connected components of $X$. Assume that the integral
cohomology of $X$ is torsion free and supported in even degrees. We prove that
there exists a constant $C$ such that any finite group $G$ acting smoothly and
effectively on $X$ has an abelian subgroup $A$ of index at most $C$, which can
be generated by at most $\sum_i[\dim X_i/2]$ elements, and which satisfies
$\chi(X_i^A)=\chi(X_i)$ for every $i$. This proves, for all such manifolds $X$,
a conjecture of \'Etienne Ghys. An essential ingredient of the proof is a
result on finite groups by Alexandre Turull and the author which uses the
classification of finite simple groups.


title: Geometric Spinors, Generalized Dirac Equation and Mirror Particles

abstract:
  It is shown that since the geometric spinors are elements of Clifford
algebras, they must have the same transformation properties as any other
Clifford number. In general, a Clifford number $\Phi$ transforms into a new
Clifford number $\Phi'$ according to $\Phi \to \Phi ' = {\rm{R}}\,\Phi
\,{\rm{S}}$, i.e., by the multiplication from the left and from the right by
two Clifford numbers ${\rm R}$ and ${\rm S}$. We study the case of $Cl(1,3)$,
which is the Clifford algebra of the Minkowski spacetime. Depending on choice
of ${\rm R}$ and ${\rm S}$, there are various possibilities, including the
transformations of vectors into 3-vectors, and the transformations of the
spinors of one minimal left ideal of $Cl(1,3)$ into another minimal left ideal.
This, among others, has implications for understanding the observed
non-conservation of parity.


title: VLBI Constraints on Type I b/c Supernovae

abstract:
  VLBI observations of supernovae and gamma-ray bursts provide almost the only
way of obtaining spatially resolved information about the sources. In
particular, a determination of the expansion velocity of the forward shock, as
well as the geometry of the fireball and its evolution with time are possible
for relatively nearby events, provided they are radio bright. Monitoring the
expansion of the shock front can provide information on the density profiles of
both the circumstellar material and on the ejecta. VLBI observations can also
potentially resolve GRB jets which are not directed along the line of sight,
providing crucial confirmation of relativistic expansion in such objects. This
review gives an overview of recent results from supernovae, including the Type
I b/c SNe 2011dh, 2009bb, and 2007gr, and discusses the prospects for future
observations.


title: Tidal stability of giant molecular clouds in the Large Magellanic Cloud

abstract:
  Star formation does not occur until the onset of gravitational collapse
inside giant molecular clouds. However, the conditions that initiate cloud
collapse and regulate the star formation process remain poorly understood.
Local processes such as turbulence and magnetic fields can act to promote or
prevent collapse. On larger scales, the galactic potential can also influence
cloud stability and is traditionally assessed by the tidal and shear effects.
In this paper, we examine the stability of giant molecular clouds (GMCs) in the
Large Magellanic Cloud (LMC) against shear and the galactic tide using CO data
from the Magellanic Mopra Assessment (MAGMA) and rotation curve data from the
literature. We calculate the tidal acceleration experienced by individual GMCs
and determine the minimum cloud mass required for tidal stability. We also
calculate the shear parameter, which is a measure of a clouds susceptibility to
disruption via shearing forces in the galactic disk. We examine whether there
are correlations between the properties and star forming activity of GMCs and
their stability against shear and tidal disruption. We find that the GMCs are
in approximate tidal balance in the LMC, and that shear is unlikely to affect
their further evolution. GMCs with masses close to the minimal stable mass
against tidal disruption are not unusual in terms of their mass, location, or
CO brightness, but we note that GMCs with large velocity dispersion tend to be
more sensitive to tidal instability. We also note that GMCs with smaller radii,
which represent the majority of our sample, tend to more strongly resist tidal
and shear disruption. Our results demonstrate that star formation in the LMC is
not inhibited by to tidal or shear instability.


title:
Long-term monitoring, time delay and microlensing in the gravitational
  lens system Q0142-100

abstract:
  We present twelve years of monitoring of the gravitational lens Q0142-100
from the Teide Observatory. The data, taken from 1999 to 2010, comprise 105
observing nights with the IAC80 telescope. The application of the delta2-method
to the dataset leads to a value of the time delay between both components of
the system of 72+/-22 days (68 per cent confidence level), consistent within
the uncertainties with the latest previous results. With this value in mind a
possible microlensing event is detected in Q0142-100.


title: Uncertainty relation for focal spots in light beams

abstract:
  Uncertainty relations for light pulses found in [Phys. Rev. A {\bf 86},
022118 (2012)] were derived in the three-dimensional case which emphasized the
localization in a volume. Here we derive the uncertainty relation for light
beams in the two-dimensional plane perpendicular to the direction of the beam
propagation which is more interesting for realistic beams. This uncertainty
relation connects the area of the focal spot with the spectrum of transverse
photon momenta. The shape of the beam that saturates the uncertainty relation
is very close to a Gaussian. The directions of the electric and magnetic field
vectors are those of the circularly polarized plane wave. Our uncertainty
relation for the focal spot is quite general but we were able to determine the
value of the lower bound only for beams made of many photons.


title:
Turing pattern formation in the Brusselator system with nonlinear
  diffusion

abstract:
  In this work we investigate the effect of density dependent nonlinear
diffusion on pattern formation in the Brusselator system. Through linear
stability analysis of the basic solution we determine the Turing and the
oscillatory instability boundaries. A comparison with the classical linear
diffusion shows how nonlinear diffusion favors the occurrence of Turing pattern
formation. We study the process of pattern formation both in 1D and 2D spatial
domains. Through a weakly nonlinear multiple scales analysis we derive the
equations for the amplitude of the stationary patterns. The analysis of the
amplitude equations shows the occurrence of a number of different phenomena,
including stable supercritical and subcritical Turing patterns with multiple
branches of stable solutions leading to hysteresis. Moreover we consider
traveling patterning waves: when the domain size is large, the pattern forms
sequentially and traveling wavefronts are the precursors to patterning. We
derive the Ginzburg-Landau equation and describe the traveling front enveloping
a pattern which invades the domain. We show the emergence of radially symmetric
target patterns, and through a matching procedure we construct the outer
amplitude equation and the inner core solution.


title:
Rewriting systems and biautomatic structures for Chinese, hypoplactic,
  and sylvester monoids

abstract:
  This paper studies complete rewriting systems and biautomaticity for three
interesting classes of finite-rank homogeneous monoids: Chinese monoids,
hypoplactic monoids, and sylvester monoids. For Chinese monoids, we first give
new presentations via finite complete rewriting systems, using more lucid
constructions and proofs than those given independently by Chen & Qui and
G\"uzel Karpuz; we then construct biautomatic structures. For hypoplactic
monoids, we construct finite complete rewriting systems and biautomatic
structures. For sylvester monoids, which are not finitely presented, we prove
that the standard presentation is an infinite complete rewriting system, and
construct biautomatic structures. Consequently, the monoid algebras
corresponding to monoids of these classes are automaton algebras in the sense
of Ufnarovskij.


title:
Multigrid algorithms for $hp$-Discontinuous Galerkin discretizations of
  elliptic problems

abstract:
  We present W-cycle multigrid algorithms for the solution of the linear system
of equations arising from a wide class of $hp$-version discontinuous Galerkin
discretizations of elliptic problems. Starting from a classical framework in
multigrid analysis, we define a smoothing and an approximation property, which
are used to prove the uniform convergence of the W-cycle scheme with respect to
the granularity of the grid and the number of levels. The dependence of the
convergence rate on the polynomial approximation degree $p$ is also tracked,
showing that the contraction factor of the scheme deteriorates with increasing
$p$. A discussion on the effects of employing inherited or non-inherited
sublevel solvers is also presented. Numerical experiments confirm the
theoretical results.


title:
Chemical and Crystallographic Characterization of the Tip Apex in
  Scanning Probe Microscopy

abstract:
  The apex atom of a W scanning probe tip reveals a non-spherical charge
distribution as probed by a CO molecule bonded to a Cu(111) surface [Welker et
al. Science, 336, 444 (2012)]. Three high-symmetry images were observed and
related to three low-index crystallographic directions of the W bcc crystal.
Open questions remained, however, including the verification that the tip was
indeed W-terminated, and whether this method can be easily applied to
distinguish other atomic species. In this work, we investigate bulk Cu and Fe
tips. In both cases we can associate our data with the fcc (Cu) and bcc (Fe)
crystal structures. A model is presented, based on the partial filling of d
orbitals, to relate the AFM images to the angular orientation of the tip
structure.


title:
Emergences of C IV narrow absorption troughs in the quasar SDSS
  J095254.10+021932.8

abstract:
  In this paper, we report on two C IV narrow absorption systems emerging from
the spectrum of the quasar SDSS J095254.10 +021932.8, which are located at
$z_{\rm abs}=2.0053$ and $z_{\rm abs}=1.8011$, respectively. These features
have velocity offsets of $\rm \sim 13,800$ and $\rm \sim 34,700~km~s^{-1}$ with
respect to the quasar, and show obviously partial coverage to the background
emission sources. The two C IV absorption systems are imprinted on the spectrum
obtained by the Sloan Digital Sky Survey (SDSS) III on 2011 March 25, which
cannot be observed from the spectrum obtained by SDSS-I/II on 2000 December 30.
The time interval of the two SDSS observations is 1186.4 d at the quasar rest
frame. Because the continuum radiation, broad emission lines and mass accretion
rate are stable for the two observations, together with the time interval of
observations, we believe that the observed spectral variations are less likely
to be caused by the changes in the ionization states of the absorbing gas or by
a new outflow, arising from the situation where there was previously no outflow
at all. Instead, they probably arise from the motions of multiple streaming gas
across the sightline of the quasar.


title:
Goal oriented adaptivity in the IRGNM for parameter identification in
  PDEs II: all-at once formulations

abstract:
  In this paper we investigate adaptive discretization of the iteratively
regularized Gauss- Newton method IRGNM. All-at-once formulations considering
the PDE and the measurement equation simultaneously allow to avoid
(approximate) solution of a potentially nonlinear PDE in each Newton step as
compared to the reduced form [22]. We analyze a least squares and a generalized
Gauss-Newton formulation and in both cases prove convergence and convergence
rates with a posteriori choice of the regularization parameters in each Newton
step and of the stopping index under certain accuracy requirements on four
quantities of interest. Estimation of the error in these quantities by means of
a weighted dual residual method is discussed, which leads to an algorithm for
adaptive mesh refinement. Numerical experiments with an implementation of this
algorithm show the numerical efficiency of this approach, which especially for
strongly nonlinear PDEs outperforms the nonlinear Tikhonov regularization
considered in [21].


title:
Reconstruction of interfaces using CGO solutions for the Maxwell
  equations

abstract:
  We deal with the problem of reconstructing interfaces using complex
geometrical optics solutions for the Maxwell system. The contributions are
twofold. First, we justify the enclosure method for the impenetrable obstacle
case avoiding any assumption on the directions of the phases of the CGO's (or
the curvature of obstacle's surface). In addition, we need only a Lipschitz
regularity of this surface. The analysis is based on some fine properties of
the corresponding layer potentials in appropriate Sobolev spaces. Second, we
justify this method also for the penetrable case, where the interface is
modeled by the jump (or the discontinuity) of the magnetic permeability $\mu$.
A key point of the analysis is the global $L^p$-estimates for the curl of the
solutions of the Maxwell system with discontinuous coefficients. These
estimates are justified here for $p$ near $2$ generalizing to the Maxwell's
case the well known Meyers's $L^p$ estimates of the gradient of the solution of
scalar divergence form elliptic problems.


title:
Towards wafer scale inductive determination of magnetostatic and dynamic
  parameters of magnetic thin films and multilayers

abstract:
  We investigate an inductive probe head suitable for non-invasive
characterization of the magnetostatic and dynamic parameters of magnetic thin
films and multilayers on the wafer scale. The probe is based on a planar
waveguide with rearward high frequency connectors that can be brought in close
contact to the wafer surface. Inductive characterization of the magnetic
material is carried out by vector network analyzer ferromagnetic resonance.
Analysis of the field dispersion of the resonance allows the determination of
key material parameters such as the saturation magnetization MS or the
effective damping parameter Meff. Three waveguide designs are tested. The
broadband frequency response is characterized and the suitability for inductive
determination of MS and Meff is compared. Integration of such probes in a wafer
prober could in the future allow wafer scale in-line testing of magnetostatic
and dynamic key material parameters of magnetic thin films and multilayers.


title: Novae in Globular Clusters

abstract:
  We present the first light curve analysis of Population II novae that
appeared in M31 globular clusters. Our light curve models, based on the
optically thick wind theory, reproduce well both the X-ray turn-on and turnoff
times with the white dwarf (WD) mass of about 1.2 Mo for M31N 2007-06b in Bol
111 and about 1.37 Mo for M31N 2010-10f in Bol 126. The transient supersoft
X-ray source CXO J004345 in Bol 194 is highly likely a nova remnant of 1.2 --
1.3 Mo WD. These WD masses are quite consistent with the temperatures deduced
from X-ray spectra. We also present the dependence of nova light curves on the
metallicity in the range from [Fe/H]=0.4 to -2.7. Whereas strong optically
thick winds are accelerated in Galactic disk novae owing to a large Fe opacity
peak, only weak winds occur in Population II novae with low Fe abundance. Thus,
nova light curves are systematically slow in low Fe environment. For an
extremely low Fe abundance normal nova outbursts may not occur unless the WD is
very massive. We encourage V or y filter observation rather than R as well as
high cadence X-ray monitorings to open quantitative studies of extragalactic
novae.


title:
Long Range Triplet Josephson Current and $0-\pi$ Transition in Tunable
  Domain Walls

abstract:
  The order parameter of superconducting pairs penetrating an inhomogeneous
magnetic material can acquire a long range triplet component (LRTC) with
non-zero spin projection. This state has been predicted and generated recently
in proximity systems and Josephson junctions. We show using an analytically
derived domain wall of an exchange spring how the LRTC emerges and can be tuned
with the twisting of the magnetization. We also introduce a new kind of
Josephson current reversal, the triplet $0-\pi$ transition, that can be
observed in one and the same system either by tuning the domain wall or by
varying temperature.


title: Roy's Largest Root Test Under Rank-One Alternatives

abstract:
  Roy's largest root is a common test statistic in multivariate analysis,
statistical signal processing and allied fields. Despite its ubiquity,
provision of accurate and tractable approximations to its distribution under
the alternative has been a longstanding open problem. Assuming Gaussian
observations and a rank one alternative, or concentrated non-centrality, we
derive simple yet accurate approximations for the most common low-dimensional
settings. These include signal detection in noise, multiple response
regression, multivariate analysis of variance and canonical correlation
analysis. A small noise perturbation approach, perhaps underused in statistics,
leads to simple combinations of standard univariate distributions, such as
central and non-central $\chi^2$ and $F$. Our results allow approximate power
and sample size calculations for Roy's test for rank one effects, which is
precisely where it is most powerful.


title: Dark matter and U(1)' symmetry for the right-handed neutrinos

abstract:
  We consider a U(1)' gauge symmetry acting on three generations of
right-handed neutrinos. The U(1)' symmetry is broken at the TeV scale and its
remnant discrete symmetry makes one of the right-handed neutrinos stable. As a
natural consequence of the anomaly cancellation, the neutrino mass matrix
consists of a combination of Type I (TeV scale) seesaw and radiative
correction. The stable right-handed neutrino communicates with the Standard
Model via s-channel exchange of the Higgs field and the U(1)' gauge boson, so
that the observed relic density for dark matter is obtained in a wide range of
the parameter space. The experimental signatures in collider and other
experiments are briefly discussed.


title:
A formula for the derivative of the p-adic L-function of the symmetric
  square of a finite slope modular form

abstract:
  Let f be a modular form of weight k and Nebentypus $\psi$. By generalizing a
construction of Dabrowski and Delbourgo, we construct a p-adic L-function
interpolating the special values of the L-function
$L(s,\mathrm{Sym}^2(f)\otimes \xi)$, where $\xi$ is a Dirichlet character. When
s=k-1 and $\xi=\psi^{-1}$, this p-adic L-function vanishes due to the presence
of a so-called trivial zero. We give a formula for the derivative at s=k-1 of
this p-adic L-function when the form f is Steinberg at p. If the weight of f is
even, the conductor is even and squarefree, and the Nebentypus is trivial this
formula implies a conjecture of Benois.