title:
Solving the Einstein constraints in periodic spaces with a multigrid
  approach

abstract:
  Novel applications of Numerical Relativity demand for more flexible
algorithms and tools. In this paper, I develop and test a multigrid solver,
based on the infrastructure provided by the Einstein Toolkit, for elliptic
partial differential equations on spaces with periodic boundary conditions.
This type of boundary often characterizes the numerical representation of
cosmological models, where space is assumed to be made up of identical copies
of a single fiducial domain, so that only a finite volume (with periodic
boundary conditions at its edges) needs to be simulated. After a few tests and
comparisons with existing codes, I use the solver to generate initial data for
an infinite, periodic, cubic black-hole lattice.


title:
Snaking states on a cylindrical surface in a perpendicular magnetic
  field

abstract:
  We calculate electronic states on a closed cylindrical surface as a model of
a core-shell nanowire. The length of the cylinder can be infinite or finite. We
define cardinal points on the circumference of the cylinder and consider a
spatially uniform magnetic field perpendicular to the cylinder axis,in the
direction South-North. The orbital motion of the electrons depends on the
radial component of the field which is not uniform around the circumference: it
is equal to the total field at North and South, but vanishes at the West and
East sides. For a strong field, when the magnetic length is comparable to the
radius of the cylinder, the electronic states at North and South become
localized cyclotron orbits, whereas at East and West the states become long and
narrow snaking orbits propagating along the cylinder. The energy of the
cyclotron states increases with the magnetic field whereas the energy of the
snaking states is stable. Consequently, at high magnetic fields the electron
density vanishes at North and South and concentrates at East and West. We
include spin-orbit interaction with linear Rashba and Dresselhaus models. For a
cylinder of finite length the Dresselhaus interaction produces an axial twist
of the charge density relative to the center of the wire, which may be
amplified in the presence of the Rashba interaction.


title:
Deformations of Lifshitz holography with the Gauss-Bonnet term in
  ($n+1$) dimensions

abstract:
  We investigate deformations of Gauss-Bonnet-Lifshitz holography in $(n+1)$
dimensional spacetime. Marginally relevant operators are dynamically generated
by a momentum scale $\Lambda \sim 0$ and correspond to slightly deformed
Gauss-Bonnet-Lifshitz spacetimes via a holographic picture. To admit
(non-trivial) sub-leading orders of the asymptotic solution for the marginal
mode, we find that the value of the dynamical critical exponent $z$ is
restricted by $z= n-1-2(n-2) \tilde{\alpha}$, where $\tilde{\alpha}$ is the
(rescaled) Gauss-Bonnet coupling constant. The generic black hole solution,
which is characterized by the horizon flux of the vector field and
$\tilde{\alpha}$, is obtained in the bulk, and we explore its thermodynamic
properties for various values of $n$ and $\tilde{\alpha}$.


title:
Influence of the Nucleon Hard Partons Distribution on J/\Psi Suppression
  in a GMC Framework

abstract:
  In a Glauber Monte Carlo framework, taking account of the transverse spatial
distribution of hard partons in the nucleon, we analyse the nuclear
modification factor $R_{dAu}$ for $J/\psi$ in d+Au collisions with the EPS09
shadowing parametrization. After the influence of nucleon hard partons
distribution is considered, a clearly upward correction is revealed for the
dependence of $R_{dAu}$ on $N_{coll}$ in peripheral d+Au collisions, however,
an unconspicuous correction is shown for the results versus $p_{T}$. The
theoretical results are in good agreement with the experimental data from
PHENIX.


title:
Subspace Embeddings and $\ell_p$-Regression Using Exponential Random
  Variables

abstract:
  Oblivious low-distortion subspace embeddings are a crucial building block for
numerical linear algebra problems. We show for any real $p, 1 \leq p < \infty$,
given a matrix $M \in \mathbb{R}^{n \times d}$ with $n \gg d$, with constant
probability we can choose a matrix $\Pi$ with $\max(1, n^{1-2/p}) \poly(d)$
rows and $n$ columns so that simultaneously for all $x \in \mathbb{R}^d$,
$\|Mx\|_p \leq \|\Pi Mx\|_{\infty} \leq \poly(d) \|Mx\|_p.$ Importantly, $\Pi
M$ can be computed in the optimal $O(\nnz(M))$ time, where $\nnz(M)$ is the
number of non-zero entries of $M$. This generalizes all previous oblivious
subspace embeddings which required $p \in [1,2]$ due to their use of $p$-stable
random variables. Using our matrices $\Pi$, we also improve the best known
distortion of oblivious subspace embeddings of $\ell_1$ into $\ell_1$ with
$\tilde{O}(d)$ target dimension in $O(\nnz(M))$ time from $\tilde{O}(d^3)$ to
$\tilde{O}(d^2)$, which can further be improved to $\tilde{O}(d^{3/2})
\log^{1/2} n$ if $d = \Omega(\log n)$, answering a question of Meng and Mahoney
(STOC, 2013).
  We apply our results to $\ell_p$-regression, obtaining a
$(1+\eps)$-approximation in $O(\nnz(M)\log n) + \poly(d/\eps)$ time, improving
the best known $\poly(d/\eps)$ factors for every $p \in [1, \infty) \setminus
\{2\}$. If one is just interested in a $\poly(d)$ rather than a
$(1+\eps)$-approximation to $\ell_p$-regression, a corollary of our results is
that for all $p \in [1, \infty)$ we can solve the $\ell_p$-regression problem
without using general convex programming, that is, since our subspace embeds
into $\ell_{\infty}$ it suffices to solve a linear programming problem.
Finally, we give the first protocols for the distributed $\ell_p$-regression
problem for every $p \geq 1$ which are nearly optimal in communication and
computation.


title: Primordial RNA Replication and Applications in PCR Technology

abstract:
  The emergence of self-replication and information transmission in life's
origin remains unexplained despite extensive research on the topic. A
hypothesis explaining the transition from a simple organic world to a complex
RNA world is offered here based on physical factors in hydrothermal vent
systems. An interdisciplinary approach is taken using techniques from
thermodynamics, fluid dynamics, oceanography, statistical mechanics, and
stochastic processes to examine nucleic acid dynamics and kinetics in a
hydrothermal vent from first principles. Analyses are carried out using both
analytic and computational methods and confirm the plausibility of a reaction
involving the PCR-like assembly of ribonucleotides. The proposal is put into
perspective with established theories on the origin of life and more generally
the onset of order and information transmission in prebiotic systems. A
biomimicry application of this hypothetical process to PCR technology is
suggested and its viability is evaluated in a rigorous logical analysis.
Optimal temperature curves begin to be established using Monte Carlo
simulation, variational calculus, and Fourier analysis. The converse argument
is also made but qualitatively, asserting that the success of such a
modification to PCR would in turn reconfirm the biological theory.


title: Metallic bonds become molecular-like in atomic-sized devices

abstract:
  Covalent molecules are characterized by directed bonds, which provide
stability-of-form to the molecules relative atomic positions. In contrast, bulk
metals are characterized by delocalized bonds, where a large number of
resonance structures ensure their high stability. However, reduced to atomic
dimensions, metallic arrangements become increasingly vulnerable to disruptive
entropic fluctuations. Using the smallest possible device, namely, a single
atom held between two atomically sharp probes, force to rupture single-atom
bridges was measured with pico-level resolution, using gold and silver.
Remarkably, measured forces are found to be a precise vector sum (directional
bonding) of cohesive forces between the central and adjacently coordinated
atoms. Over three to four times stronger than bulk, the directional bonds
provide high configurational stability to atomic-sized metallic devices, just
as delocalization-induced resonance stabilization is the emergent response of
bulk metals. Results open new opportunity for molecular electronics without
complications arising from metal/molecule interfaces.


title: Some Solvable Quantum Mechanical Models and Their Symmetries

abstract:
  This thesis is focused on some solvable quantum mechanical models and their
associated symmetries.


title:
Sets of Salem type and sharpness of the $L^2$-Fourier restriction
  theorem

abstract:
  We construct Salem sets on the real line with endpoint Fourier decay and
near-endpoint regularity properties. This complements a result of \L aba and
Pramanik, who obtained near-endpoint Fourier decay and endpoint regularity
properties. We then modify the construction to extend a theorem of Hambrook and
\L aba to show sharpness of the $L^2$-Fourier restriction estimate by
Mockenhaupt and Bak-Seeger, including the case where the Hausdorff and Fourier
dimension do not coincide.


title: On/Off Macrocells and Load Balancing in Heterogeneous Cellular Networks

abstract:
  The rate distribution in heterogeneous networks (HetNets) greatly benefits
from load balancing, by which mobile users are pushed onto lightly-loaded small
cells despite the resulting loss in SINR. This offloading can be made more
aggressive and robust if the macrocells leave a fraction of time/frequency
resource blank, which reduces the interference to the offloaded users. We
investigate the joint optimization of this technique - referred to in 3GPP as
enhanced intercell interference coordination (eICIC) via almost blank subframes
(ABSs) - with offloading in this paper. Although the joint cell association and
blank resource (BR) problem is nominally combinatorial, by allowing users to
associate with multiple base stations (BSs), the problem becomes convex, and
upper bounds the performance versus a binary association. We show both
theoretically and through simulation that the optimal solution of the relaxed
problem still results in an association that is mostly binary. The optimal
association differs significantly when the macrocell is on or off; in
particular the offloading can be much more aggressive when the resource is left
blank by macro BSs. Further, we observe that jointly optimizing the offloading
with BR is important. The rate gain for cell edge users (the worst 3-10%) is
very large - on the order of 5-10x - versus a naive association strategy
without macrocell blanking.


title:
Testing Accuracy and Precision of Existing Photometry Algorithms on
  Moving Targets

abstract:
  Previous studies determining which astronomical photometry software is best
suited for a particular dataset are usually focused on speed, source
classification, and/or meeting a sensitivity requirement. For faint objects in
particular, the priority is given to maximizing signal-to-noise. Photometry of
moving targets offers additional challenges (i) to aperture photometry because
background object contamination varies from image to image, and (ii) to
routines that build a PSF model from point sources in the image because trailed
field stars do not perfectly represent the PSF of the untrailed target. Here,
we present the results of testing several photometry algorithms (tphot,
DAOPHOT, DoPHOT, APT, and multiple techniques within Source Extractor and
IRAF's PHOT) on data for a faint, slow-moving solar system object with a known
light curve. We find that the newly-developed tphot software most accurately
and precisely reproduces the object's true light curve, with particular
advantages in centroiding, exclusion of contaminants from the target's flux,
and fitting flux in the wings of the point-spread function.


title: A sub-Mercury-sized exoplanet

abstract:
  Since the discovery of the first exoplanet we have known that other planetary
systems can look quite unlike our own. However, until recently we have only
been able to probe the upper range of the planet size distribution. The high
precision of the Kepler space telescope has allowed us to detect planets that
are the size of Earth and somewhat smaller, but no previous planets have been
found that are smaller than those we see in our own Solar System. Here we
report the discovery of a planet significantly smaller than Mercury. This tiny
planet is the innermost of three planets that orbit the Sun-like host star,
which we have designated Kepler-37. Owing to its extremely small size, similar
to that of Earth's Moon, and highly irradiated surface, Kepler-37b is probably
a rocky planet with no atmosphere or water, similar to Mercury.


title:
Diversity Backpressure Scheduling and Routing with Mutual Information
  Accumulation in Wireless Ad-hoc Networks

abstract:
  We suggest and analyze algorithms for routing in multi-hop wireless ad-hoc
networks that exploit mutual information accumulation as the physical layer
transmission scheme, and are capable of routing multiple packet streams
(commodities) when only the average channel state information is present and
that only locally. The proposed algorithms are modifications of the Diversity
Backpressure (DIVBAR) algorithm, under which the packet whose commodity has the
largest "backpressure metric" is chosen to be transmitted and is forwarded
through the link with the largest differential backlog (queue length). In
contrast to traditional DIVBAR, each receiving node stores and accumulates the
partially received packet in a separate "partial packet queue", thus increasing
the probability of successful reception during a later possible retransmission.
We present two variants of the algorithm: DIVBAR-RMIA, under which all the
receiving nodes clear the received partial information of a packet once one or
more receiving nodes firstly decode the packet; and DIVBAR-MIA, under which all
the receiving nodes retain the partial information of a packet until the packet
has reached its destination. We characterize the network capacity region with
RMIA and prove that (under certain mild conditions) it is strictly larger than
the network capacity region with the repetition (REP) transmission scheme that
is used by the traditional DIVBAR. We also prove that DIVBAR-RMIA is
throughput-optimum among the polices with RMIA, i.e., it achieves the network
capacity region with RMIA, which in turn demonstrates that DIVBAR-RMIA
outperforms traditional DIVBAR on the achievable throughput. Moreover, we prove
that DIVBAR-MIA performs at least as well as DIVBAR-RMIA with respect to
throughput. Simulations also confirm these results.


title: Fano resonance in Raman scattering of graphene

abstract:
  Fano resonances and their strong doping dependence are observed in Raman
scattering of single-layer graphene (SLG). As the Fermi level is varied by a
back-gate bias, the Raman G band of SLG exhibits an asymmetric line shape near
the charge neutrality point as a manifestation of a Fano resonance, whereas the
line shape is symmetric when the graphene sample is electron or hole doped.
However, the G band of bilayer graphene (BLG) does not exhibit any Fano
resonance regardless of doping. The observed Fano resonance can be interpreted
as interferences between the phonon and excitonic many-body spectra in SLG. The
absence of a Fano resonance in the Raman G band of BLG can be explained in the
same framework since excitonic interactions are not expected in BLG.


title: All the shapes of spaces: a census of small 3-manifolds

abstract:
  In this work we present a complete (no misses, no duplicates) census for
closed, connected, orientable and prime 3-manifolds induced by plane graphs
with a bipartition of its edge set (blinks) up to $k=9$ edges. Blinks form a
universal encoding for such manifolds. In fact, each such a manifold is a
subtle class of blinks, \cite{lins2013B}. Blinks are in 1-1 correpondence with
{\em blackboard framed links}, \cite {kauffman1991knots, kauffman1994tlr} We
hope that this census becomes as useful for the study of concrete examples of
3-manifolds as the tables of knots are in the study of knots and links.


title: Lower bounds to the spectral gap of Davies generators

abstract:
  We construct lower bounds to the spectral gap of a family of Lindblad
generators known as Davies maps. These maps describe the thermalization of
quantum systems weakly coupled to a heat bath. The steady state of these
systems is given by the Gibbs distribution with respect to the system
Hamiltonian. The bounds can be evaluated explicitly, when the eigenbasis and
the spectrum of the Hamiltonian is known. A crucial assumption is that the
spectrum of the Hamiltonian is non-degenerate. Furthermore, we provide a
counterexample to the conjecture, that the convergence rate is always
determined by the gap of the associated Pauli master equation. We conclude,
that the full dynamics of the Lindblad generator has to be considered. Finally,
we present several physical example systems for which the bound to the spectral
gap is evaluated.

categories: quant-ph cond-mat.stat-mech math-ph math.MP


title:
Finite-Length and Asymptotic Analysis of Correlogram for Undersampled
  Data

abstract:
  This paper studies a spectrum estimation method for the case that the samples
are obtained at a rate lower than the Nyquist rate. The method is referred to
as the correlogram for undersampled data. The algorithm partitions the spectrum
into a number of segments and estimates the average power within each spectral
segment. This method is able to estimate the power spectrum density of a signal
from undersampled data without essentially requiring the signal to be sparse.
We derive the bias and the variance of the spectrum estimator, and show that
there is a tradeoff between the accuracy of the estimation, the frequency
resolution, and the complexity of the estimator. A closed-form approximation of
the estimation variance is also derived, which clearly shows how the variance
is related to different parameters. The asymptotic behavior of the estimator is
also investigated, and it is proved that this spectrum estimator is consistent.
Moreover, the estimation made for different spectral segments becomes
uncorrelated as the signal length tends to infinity. Finally, numerical
examples and simulation results are provided, which approve the theoretical
conclusions.


title:
Solar source of energetic particles in interplanetary space during the
  2006 December 13 event

abstract:
  An X3.4 solar flare and a fast halo coronal mass ejection (CME) occurred on
2006 December 13, accompanied by a high flux of energetic particles recorded
both in near-Earth space and at ground level. Our purpose is to provide
evidence of flare acceleration in a major solar energetic particle (SEP) event.
We first present observations from ACE/EPAM, GOES, and the Apatity neutron
monitor. It is found that the initial particle release time coincides with the
flare emission and that the spectrum becomes softer and the anisotropy becomes
weaker during particle injection, indicating that the acceleration source
changes from a confined coronal site to a widespread interplanetary CME-driven
shock. We then describe a comprehensive study of the associated flare active
region. By use of imaging data from HINODE/SOT and SOHO/MDI magnetogram, we
infer the flare magnetic reconnection rate in the form of the magnetic flux
change rate. This correlates in time with the microwave emission, indicating a
physical link between the flare magnetic reconnection and the acceleration of
nonthermal particles. Combining radio spectrograph data from Huairou/NOAC,
Culgoora/IPS, Learmonth/RSTN, and WAVES/WIND leads to a continuous and
longlasting radio burst extending from a few GHz down to several kHz. Based on
the photospheric vector magnetogram from Huairou/NOAC and the nonlinear force
free field (NFFF) reconstruction method, we derive the 3D magnetic field
configuration shortly after the eruption. Furthermore, we also compute coronal
field lines extending to a few solar radii using a potential-field
source-surface (PFSS) model. Both the so-called type III-l burst and the
magnetic field configuration suggest that open-field lines extend from the
flare active region into interplanetary space, allowing the accelerated and
charged particles escape.


title:
Comparing composite likelihood methods based on pairs for spatial
  Gaussian random fieldsM

abstract:
  In the last years there has been a growing interest in proposing methods for
estimating covariance functions for geostatistical data. Among these, maximum
likelihood estimators have nice features when we deal with a Gaussian model.
However maximum likelihood becomes impractical when the number of observations
is very large. In this work we review some solutions and we contrast them in
terms of loss of statistical efficiency and computational burden. Specifically
we focus on three types of weighted composite likelihood functions based on
pairs and we compare them with the method of covariance tapering. Asymptotics
properties of the three estimation methods are derived. We illustrate the
effectiveness of the methods through theoretical examples, simulation
experiments and by analysing a data set on yearly total precipitation anomalies
at weather stations in the United States.


title:
Constraints on porosity and mass loss in O-star winds from modeling of
  X-ray emission line profile shapes

abstract:
  We fit X-ray emission line profiles in high resolution XMM-Newton and Chandra
grating spectra of the early O supergiant Zeta Pup with models that include the
effects of porosity in the stellar wind. We explore the effects of porosity due
to both spherical and flattened clumps. We find that porosity models with
flattened clumps oriented parallel to the photosphere provide poor fits to
observed line shapes. However, porosity models with isotropic clumps can
provide acceptable fits to observed line shapes, but only if the porosity
effect is moderate. We quantify the degeneracy between porosity effects from
isotropic clumps and the mass-loss rate inferred from the X-ray line shapes,
and we show that only modest increases in the mass-loss rate (<~ 40%) are
allowed if moderate porosity effects (h_infinity <~ R_*) are assumed to be
important. Large porosity lengths, and thus strong porosity effects, are ruled
out regardless of assumptions about clump shape. Thus, X-ray mass-loss rate
estimates are relatively insensitive to both optically thin and optically thick
clumping. This supports the use of X-ray spectroscopy as a mass-loss rate
calibration for bright, nearby O stars.


title:
Study of exclusive two-photon production of W(+)W(-) in pp collisions at
  sqrt(s) = 7 TeV and constraints on anomalous quartic gauge couplings

abstract:
  A search for exclusive or quasi-exclusive W(+)W(-) production by
photon-photon interactions, pp to p(*)W(+)W(-)p(*), at sqrt(s) = 7 TeV is
reported using data collected by the CMS detector with an integrated luminosity
of 5.05 inverse femtobarns. Events are selected by requiring a mu(+/-)e(-/+)
vertex with no additional associated charged tracks and dilepton transverse
momentum pt(mu(+/-)e(-/+)) > 30 GeV. Two events passing all selection
requirements are observed in the data, compared to a standard model expectation
of 2.2 +/- 0.4 signal events with 0.84 +/- 0.15 background. The tail of the
dilepton pt distribution is studied for deviations from the standard model. No
events are observed with pt > 100 GeV. Model-independent upper limits are
computed and compared to predictions involving anomalous quartic gauge
couplings. The limits on the parameters a[W,(0,C)]/Lambda^2 with a dipole form
factor and an energy cutoff Lambda(cutoff) = 500 GeV are of the order of 10E-4.


title:
Search for Gamma-ray Spectral Lines with the Fermi Large Area Telescope
  and Dark Matter Implications

abstract:
  Weakly Interacting Massive Particles (WIMPs) are a theoretical class of
particles that are excellent dark matter candidates. WIMP annihilation or decay
may produce essentially monochromatic gamma rays detectable by the Fermi Large
Area Telescope (LAT) against the astrophysical gamma-ray emission of the
Galaxy. We have searched for spectral lines in the energy range 5--300 GeV
using 3.7 years of data, reprocessed with updated instrument calibrations and
an improved energy dispersion model compared to the previous Fermi-LAT
Collaboration line searches. We searched in five regions selected to optimize
sensitivity to different theoretically-motivated dark matter density
distributions. We did not find any globally significant lines in our a priori
search regions and present 95% confidence limits for annihilation cross
sections of self-conjugate WIMPs and decay lifetimes. Our most significant fit
occurred at 133 GeV in our smallest search region and had a local significance
of 3.3 standard deviations, which translates to a global significance of 1.5
standard deviations. We discuss potential systematic effects in this search,
and examine the feature at 133 GeV in detail. We find that both the use of
reprocessed data and of additional information in the energy dispersion model
contribute to the reduction in significance of the line-like feature near 130
GeV relative to significances reported in other works. We also find that the
feature is narrower than the LAT energy resolution at the level of 2 to 3
standard deviations, which somewhat disfavors the interpretation of the 133 GeV
feature as a real WIMP signal.


title: Realizing a lattice spin model with polar molecules

abstract:
  With the recent production of polar molecules in the quantum regime,
long-range dipolar interactions are expected to facilitate the understanding of
strongly interacting many-body quantum systems and to realize lattice spin
models for exploring quantum magnetism. In atomic systems, where interactions
require wave function overlap, effective spin interactions on a lattice can be
realized via superexchange; however, the coupling is weak and limited to
nearest-neighbor interactions. In contrast, dipolar interactions exist in the
absence of tunneling and extend beyond nearest neighbors. This allows coherent
spin dynamics to persist even at high entropy and low lattice filling. Effects
of dipolar interactions in ultracold molecular gases have so far been limited
to the modification of chemical reactions. We now report the observation of
dipolar interactions of polar molecules pinned in a 3D optical lattice. We
realize a lattice spin model with spin encoded in rotational states, prepared
and probed by microwaves. This spin-exchange interaction arises from the
resonant exchange of rotational angular momentum between two molecules. We
observe clear oscillations in the evolution of the spin coherence in addition
to an overall decay. The frequency of these oscillations, the strong dependence
of the spin coherence time on the lattice filling, and the effect of a
multi-pulse sequence designed to reverse dynamics due to two-body exchange
interactions all provide evidence of dipolar interactions. We also demonstrate
suppression of loss in weak lattices due to a quantum Zeno mechanism.
Measurements of these tunneling-induced losses allow us to independently
determine the lattice filling factor. These results comprise an initial
exploration of the behavior of many-body spin models with direct, long-range
spin interactions and lay the groundwork for future studies of many-body
dynamics in spin lattices.


title: Trajectory Characters of Rogue Waves

abstract:
  We present a simple representation for arbitrary-order rogue wave solution
and study on the trajectories of them explicitly. We find that the global
trajectories on temporal-spatial distribution all look like "X" shape for rogue
waves. Short-time prediction on rogue wave can be done through measuring the
information contained in the initial perturbation twice.


title: Enhanced Schwinger's pair production in many-center systems

abstract:
  Electron-positron pair production is considered for many-center systems with
multiple bare nuclei immersed in a constant electric field. It is shown that
there are two distinct regimes where the pair production rate is enhanced. At
small interatomic distance, the effective charge of the nuclei approaches the
critical charge where the ground state dives into the negative continuum. This
facilitates the transition from the negative to the positive energy states,
which in turns, increases the pair production rate. At larger atomic distance,
the enhancement is due to the crossing of resonances and the pair production
proceeds by the Resonantly Enhanced Pair Production (REPP) mechanism. These
processes are studied within a simple one-dimensional model. A numerical method
is developed to evaluate the transmission coefficient in relativistic quantum
mechanics, which is required in the calculation of the pair production rate.
The latter is evaluated for systems with many (up to five) nuclei. It is shown
that the production rate for many-center systems can reach a few orders of
magnitude above Schwinger's tunnelling result in a static field.


title: Optimal Periodic Sensor Scheduling in Networks of Dynamical Systems

abstract:
  We consider the problem of finding optimal time-periodic sensor schedules for
estimating the state of discrete-time dynamical systems. We assume that
{multiple} sensors have been deployed and that the sensors are subject to
resource constraints, which limits the number of times each can be activated
over one period of the periodic schedule. We seek an algorithm that strikes a
balance between estimation accuracy and total sensor activations over one
period. We make a correspondence between active sensors and the nonzero columns
of estimator gain. We formulate an optimization problem in which we minimize
the trace of the error covariance with respect to the estimator gain while
simultaneously penalizing the number of nonzero columns of the estimator gain.
This optimization problem is combinatorial in nature, and we employ the
alternating direction method of multipliers (ADMM) to find its locally optimal
solutions. Numerical results and comparisons with other sensor scheduling
algorithms in the literature are provided to illustrate the effectiveness of
our proposed method.


title:
Coronal jets, magnetic topologies, and the production of interplanetary
  electron streams

abstract:
  We investigate the acceleration source of the impulsive solar energetic
particle (SEP) events on 2007 January 24. Combining the in situ electron
measurements and remote-sensing solar observations, as well as the calculated
magnetic fields obtained from a potential-field source-surface model, we
demonstrate that the jets associated with the hard X-ray flares and type-III
radio bursts, rather than the slow and partial coronal mass ejections, are
closely related to the production of interplanetary electron streams. The jets,
originated from the well-connected active region (AR 10939) whose magnetic
polarity structure favors the eruption, are observed to be forming in a coronal
site, extending to a few solar radii, and having a good temporal correlation
with the electron solar release. The open-field lines near the jet site are
rooted in a negative polarity, along which energetic particles escape from the
flaring AR to the near-Earth space, consistent with the in situ electron pitch
angle distribution. The analysis enables us to propose a coronal magnetic
topology relating the impulsive SEP events to their solar source.


title: Critical points of master functions and the mKdV hierarchy of type A^2_2

abstract:
  We consider the population of critical points generated from the critical
point of the master function with no variables, which is associated with the
trivial representation of the affine Lie algebra $A^2_2$. We describe how the
critical points of this population define rational solutions of the equations
of the mKdV hierarchy associated with $A^2_2$.


title:
Major electron events and coronal magnetic configurations of the related
  solar active regions

abstract:
  A statistical survey of 26 major electron events during the period 2002
February through the end of solar cycle 23 is presented. We have obtained
electron solar onset times and the peak flux spectra for each event by fitting
to a powerlaw spectrum truncated by an exponential high-energy tail. We also
derived the coronal magnetic configurations of the related solar active regions
(ARs) from the potential-field source-surface model. It is found that (1) 10 of
the 11 well-connected open field-line events are prompt events whose solar
onset times coincide with the maxima of flare emission and 13 of the 14 closed
field-line events are delayed events. (2) A not-wellconnected open field-line
event and one of the closed field-line events are prompt events, they are both
associated with large-scale coronal disturbances or dimming. (3)An averaged
harder spectrum is found in open field-line events compared with the closed
ones. Specifically, the averaged spectral index is of 1.6 +/- 0.3 in open
field-line events and of 2.0 +/- 0.4 in closed ones. The spectra of three
closed field-line events show infinite rollover energies E0. These correlations
clearly establish a significant link between the coronal magnetic field-line
topology and the escape of charged particles from the flaring ARs into
interplanetary space during the major solar energetic particle events.


title: Level Densities of Heavy Nuclei by the Shell Model Monte Carlo Method

abstract:
  The microscopic calculation of nuclear level densities in the presence of
correlations is a difficult many-body problem. The shell model Monte Carlo
method provides a powerful technique to carry out such calculations using the
framework of the configuration-interaction shell model in spaces that are many
orders of magnitude larger than spaces that can be treated by conventional
methods. We present recent applications of the method to the calculation of
level densities and their collective enhancement factors in heavy nuclei. The
calculated level densities are in close agreement with experimental data.


title:
Electron and proton acceleration during the first ground level
  enhancement of solar cycle 24

abstract:
  High-energy particles were recorded by near-Earth spacecraft and ground-based
neutron monitors (NMs) on 2012 May 17. This event was the first ground level
enhancement (GLE) of solar cycle 24. In this study, we try to identify the
acceleration source(s) of solar energetic particles by combining in situ
particle measurements from the WIND/3DP, GOES 13, and solar cosmic rays
registered by several NMs, as well as remote-sensing solar observations from
SDO/AIA, SOHO/LASCO, and RHESSI. We derive the interplanetary magnetic field
(IMF) path length (1.25 +/- 0.05 AU) and solar particle release time (01:29 +/-
00:01 UT) of the first arriving electrons by using their velocity dispersion
and taking into account contamination effects. We found that the electron
impulsive injection phase, indicated by the dramatic change in the spectral
index, is consistent with flare non-thermal emission and type III radio bursts.
Based on the potential field source surface concept, modeling of the open-field
lines rooted in the active region has been performed to provide escape channels
for flare-accelerated electrons.Meanwhile, relativistic protons are found to be
released 10 minutes later than the electrons, assuming their scatter-free
travel along the same IMF path length. Combining multi-wavelength imaging data
of the prominence eruption and coronal mass ejection (CME), we obtain evidence
that GLE protons, with an estimated kinetic energy of 1.12 GeV, are probably
accelerated by the CME-driven shock when it travels to 3.07 solar radii. The
time-of-maximum spectrum of protons is typical for shock wave acceleration.


title:
Explicit formulae for spectral norms of circulant-type matrices with
  some given entries

abstract:
  In this paper we investigate the spectral norm for circulant matrices, whose
entries are modified Fibonacci numbers and Lucas numbers. We obtain the
identity estimations for the spectral norms. Some numerical test results are
listed to verify the results using those approaches.


title:
To Reserve or Not to Reserve: Optimal Online Multi-Instance Acquisition
  in IaaS Clouds

abstract:
  Infrastructure-as-a-Service (IaaS) clouds offer diverse instance purchasing
options. A user can either run instances on demand and pay only for what it
uses, or it can prepay to reserve instances for a long period, during which a
usage discount is entitled. An important problem facing a user is how these two
instance options can be dynamically combined to serve time-varying demands at
minimum cost. Existing strategies in the literature, however, require either
exact knowledge or the distribution of demands in the long-term future, which
significantly limits their use in practice. Unlike existing works, we propose
two practical online algorithms, one deterministic and another randomized, that
dynamically combine the two instance options online without any knowledge of
the future. We show that the proposed deterministic (resp., randomized)
algorithm incurs no more than 2-alpha (resp., e/(e-1+alpha)) times the minimum
cost obtained by an optimal offline algorithm that knows the exact future a
priori, where alpha is the entitled discount after reservation. Our online
algorithms achieve the best possible competitive ratios in both the
deterministic and randomized cases, and can be easily extended to cases when
short-term predictions are reliable. Simulations driven by a large volume of
real-world traces show that significant cost savings can be achieved with
prevalent IaaS prices.


title: Local cohomology annihilators and Macaulayfication

abstract:
  The aim of this paper is to study a deep connection between local cohomology
annihilators and Macaulayfication and arithmetic Macaulayfication over a local
ring. Local cohomology annihilators appear through the notion of p-standard
system of parameters. For a local ring, we prove an equivalence of the
existence of Macaulayfications; the existence of a p-standard system of
parameters; being a quotient of a Cohen-Macaulay local ring; and the
verification of Faltings' Annihilator theorem. For a finitely generated module
which is unmixed and faithful, we prove an equivalence of the existence of an
arithmetic Macaulayfication and the existence of a p-standard system of
parameters; and both are proved to be equivalent to the existence of an
arithmetic Macaulayfication on the ground ring. A connection between
Macaulayfication and universal catenaricity is also discussed.


title:
Integrating tabu search and VLSN search to develop enhanced algorithms:
  A case study using bipartite boolean quadratic programs

abstract:
  The bipartite boolean quadratic programming problem (BBQP) is a
generalization of the well studied boolean quadratic programming problem. The
model has a variety of real life applications; however, empirical studies of
the model are not available in the literature, except in a few isolated
instances. In this paper, we develop efficient heuristic algorithms based on
tabu search, very large scale neighborhood (VLSN) search, and a hybrid
algorithm that integrates the two. The computational study establishes that
effective integration of simple tabu search with VLSN search results in
superior outcomes, and suggests the value of such an integration in other
settings. Complexity analysis and implementation details are provided along
with conclusions drawn from experimental analysis. In addition, we obtain
solutions better than the best previously known for almost all medium and large
size benchmark instances.


title:
Effects of excitation frequency on high-order terahertz sideband
  generation in semiconductors

abstract:
  We theoretically investigate the effects of the excitation frequency on the
plateau of high-order terahertz sideband generation (HSG) in semiconductors
driven by intense terahertz (THz) fields. We find that the plateau of the
sideband spectrum strongly depends on the detuning between the NIR laser field
and the band gap. We use the quantum trajectory theory (three-step model) to
understand the HSG. In the three-step model, an electron-hole pair is first
excited by a weak laser, then driven by the strong THz field, and finally
recombine to emit a photon with energy gain. When the laser is tuned below the
band gap (negative detuning), the electron-hole generation is a virtual process
that requires quantum tunneling to occur. When the energy gained by the
electron-hole pair from the THz field is less than 3.2 times the ponderomotive
energy, the electron and the hole can be driven to the same position and
recombine without quantum tunneling, so the HSG will have large probability
amplitude. This leads to a plateau feature of the HSG spectrum with a
high-frequency cutoff at about 3.2 times the ponderomotive energy above the
band gap. Such a plateau feature is similar to the case of high-order harmonics
generation in atoms where electrons have to overcome the binding energy to
escape the atomic core. A particularly interesting excitation condition in HSG
is that the laser can be tuned above the band gap (positive detuning),
corresponding to the unphysical "negative" binding energy in atoms for
high-order harmonic generation. Now the electron-hole pair is generation by
real excitation, but the recombination process can be real or virtual depending
on the energy gained from the THz field, which determines the plateau feature
in HSG.


title:
Two-year monitoring of intra-day variability of quasar 1156+295 at 4.8
  GHz

abstract:
  The quasar 1156+295 (4C +29.45) is one of the targets in the Urumqi
monitoring program which aimed to search for evidence of annual modulation in
the timescales of intra-day variable (IDV) sources. The IDV observations of
1156+295 were carried out nearly monthly from October 2007 to October 2009,
with the Urumqi 25m radio telescope at 4.8 GHz. The source has shown prominent
IDV of total flux density in most observing sessions with variability
timescales of <= 1 day at 4.8 GHz. The estimated IDV timescales seem to follow
an annual cycle that can be fitted with an anisotropic interstellar
scintillation (ISS) model suggesting that a significant part of the flux
density variations is due to ISS. The source underwent a dramatic flare in
2008. We studied the possible consequences of the flare on the IDV of 1156+295
by comparing the changes in its IDV characteristics with the evolution of the
43 GHz Very Long Baseline Array (VLBA) core size of the source. Conclusions:
The quasar 1156+295 shows evidence for an annual modulation of its IDV
timescales at 4.8 GHz, the ISS-induced IDV timescales and variability strength
might be affected by the overall activity state of the source core. More
frequent IDV and VLBI measurements are required to confirm the relation between
the IDV appearance and the core-size evolution of the source.


title: Isometric embeddings via heat kernel

abstract:
  For any n-dimensional compact Riemannian manifold (M,g), we construct a
canonical t-family of isometric embeddings I_{t}: M->R^{q(t)}, with t>0
sufficiently small and q(t)>>t^{-n/2}. This is done by intrinsically perturbing
the heat kernel embedding introduced in [BBG]. As t->0, asymptotic geometry of
the embedded images is discussed.


title:
On the Integrability of Four Dimensional N=2 Gauge Theories in the Omega
  Background

abstract:
  We continue to investigate the relationship between the infrared physics of
N=2 supersymmetric gauge theories in four dimensions and various integrable
models such as Gaudin, Calogero-Moser and quantum spin chains. We prove
interesting dualities among some of these integrable systems by performing
different, albeit equivalent, quantizations of the Seiberg-Witten curve of the
four dimensional theory. We also discuss conformal field theories related to
N=2 4d gauge theories by the Alday-Gaiotto-Tachikawa (AGT) duality and the role
of conformal blocks of those CFTs in the integrable systems. As a consequence,
the equivalence of conformal blocks of rank two Toda and
Novikov-Wess-Zumino-Witten (WZNW) theories on the torus with punctures is
found.


title:
A generic, hierarchical framework for massively parallel Wang-Landau
  sampling

abstract:
  We introduce a parallel Wang-Landau method based on the replica-exchange
framework for Monte Carlo simulations. To demonstrate its advantages and
general applicability for simulations of complex systems, we apply it to
different spin models including spin glasses, the Ising model and the Potts
model, lattice protein adsorption, and the self-assembly process in amphiphilic
solutions. Without loss of accuracy, the method gives significant speed-up and
potentially scales up to petaflop machines.


title:
A numerical dressing method for the nonlinear superposition of solutions
  of the KdV equation

abstract:
  In this paper we present the unification of two existing numerical methods
for the construction of solutions of the Korteweg-de Vries (KdV) equation. The
first method is used to solve the Cauchy initial-value problem on the line for
rapidly decaying initial data. The second method is used to compute
finite-genus solutions of the KdV equation. The combination of these numerical
methods allows for the computation of exact solutions that are asymptotically
(quasi-)periodic finite-gap solutions and are a nonlinear superposition of
dispersive, soliton and (quasi-)periodic solutions in the finite (x,t)-plane.
Such solutions are referred to as superposition solutions. We compute these
solutions accurately for all values of x and t.


title: Straight-line programs with memory and matrix Bruhat decomposition

abstract:
  We advocate that straight-line programs designed for algebraic computations
should be accompanied by a comprehensive complexity analysis that takes into
account both the number of fundamental algebraic operations needed, as well as
memory requirements arising during evaluation. We introduce an approach for
formalising this idea and, as illustration, construct and analyse straight-line
programs for the Bruhat decomposition of $d \times d$ matrices with determinant
1 over a finite field of order $q$ that have length $O(d^2 \log(q))$ and
require storing only $O(\log(q))$ matrices during evaluation.


title:
A general approach to the joint asymptotic analysis of statistics from
  sub-samples

abstract:
  In time series analysis, statistics based on collections of estimators
computed from sub-samples play a crucial role in an increasing variety of
important applications. Proving results about the joint asymptotic distribution
of such statistics is challenging since it typically involves a nontrivial
verification of technical conditions and tedious case-by-case asymptotic
analysis. In this paper, we provide a novel technique that allows to circumvent
those problems in a general setting. Our approach consists of two major steps:
a probabilistic part which is mainly concerned with weak convergence of
sequential empirical processes, and an analytic part providing general ways to
extend this weak convergence to functionals of the sequential empirical
process. Our theory provides a unified treatment of asymptotic distributions
for a large class of statistics, including recently proposed self-normalized
statistics and sub-sampling based p-values. In addition, we comment on the
consistency of bootstrap procedures and obtain general results on compact
differentiability of certain mappings that seem to be of independent interest.


title: Level Repulsion for a class of decaying random potentials

abstract:
  In this paper we consider the Anderson model with decaying randomness and
show that statistics near the band edges in the absolutely continuous spectrum
in dimensions $d \geq 3$ is independent of the randomness and agrees with that
of the free part. We also consider the operators at small coupling and identify
the length scales at which the statistics agrees with the free one in the limit
when the coupling constant goes to zero.


title:
Particle-in-cell simulations of collisionless shock formation via
  head-on merging of two laboratory supersonic plasma jets

abstract:
  We describe numerical simulations, using the particle-in-cell (PIC) and
hybrid-PIC code Lsp [T. P. Hughes et al., Phys. Rev. ST Accel. Beams 2, 110401
(1999)], of the head-on merging of two laboratory supersonic plasma jets. The
goals of these experiments are to form and study astrophysically relevant
collisionless shocks in the laboratory. Using the plasma jet initial conditions
(density ~ 10^14-10^16 cm^(-3), temperature ~ few eV, and propagation speed ~
20-100 km/s), large-scale simulations of jet propagation demonstrate that
interactions between the two jets are essentially collisionless at the merge
region. In highly resolved one- and two-dimensional simulations, we show that
collisionless shocks are generated by the merging jets when immersed in applied
magnetic fields (B ~ 0.1-1 kG). At expected plasma jet speeds of up to 100
km/s, our simulations do not give rise to unmagnetized collisionless shocks,
which require much higher velocities. The orientation of the magnetic field and
the axial and transverse density gradients of the jets have a strong effect on
the nature of the interaction. We compare some of our simulation results with
those of previously published PIC simulation studies of collisionless shock
formation.


title: On a Heath-Jarrow-Morton approach for stock options

abstract:
  This paper aims at transferring the philosophy behind Heath-Jarrow-Morton to
the modelling of call options with all strikes and maturities. Contrary to the
approach by Carmona and Nadtochiy (2009) and related to the recent contribution
Carmona and Nadtochiy (2012) by the same authors, the key parametrisation of
our approach involves time-inhomogeneous L\'evy processes instead of local
volatility models. We provide necessary and sufficient conditions for absence
of arbitrage. Moreover we discuss the construction of arbitrage-free models.
Specifically, we prove their existence and uniqueness given basic building
blocks.


title: Two Observations on the Perturbed Wedge

abstract:
  Francisco Santos has described a new construction, per- turbing apart a
non-simple face, to offer a counterexample to the Hirsch Conjecture. We offer
two observations about this perturbed wedge con- struction, regarding its
effect on edge-paths. First, that an all-but- simple spindle of dimension d and
length d + 1 is a counterexample to the nonrevisiting conjecture. Second, that
there are conditions under which the perturbed wedge construction does not
increase the diameter. NOTE: These are simply working notes, offering two
observations on the construction identified by Santos.


title:
Depletion and fluctuations of a trapped dipolar Bose-Einstein condensate
  in the roton regime

abstract:
  We consider the non-condensate density and density fluctuations of a trapped
dipolar Bose-Einstein condensate, focusing on the regime where a roton-like
excitation spectrum develops. Our results show that a characteristic peak in
the non-condensate density occurs at trap center due to the rotons. In this
regime we also find that the anomalous density becomes positive and peaked,
giving rise to enhanced density fluctuations. We calculate the non-condensate
density in momentum space and show that a small momentum halo is associated
with the roton excitations.


title:
Pathwise uniqueness for a SPDE with H\"older continuous coefficient
  driven by \alpha-stable noise

abstract:
  In this paper we study the pathwise uniqueness of solution to the following
stochastic partial differential equation (SPDE) with H\"older continuous
coefficient:
  \begin{eqnarray*} \frac{\partial X_t(x)}{\partial t}=\frac{1}{2} \Delta
X_t(x) +G(X_t(x))+H(X_{t-}(x)) \dot{L}_t(x),~~~ t>0, ~x\in\mathbb{R},
  \end{eqnarray*} where $\dot{L}$ denotes an $\alpha$-stable white noise on
$\mathbb{R}_+\times \mathbb{R}$ without negative jumps, $G$ satisfies the
Lipschitz condition and $H$ is nondecreasing and $\beta$-H\"older continuous
for $1<\alpha<2$ and $0<\beta<1$.
  For $G\equiv0$ and $H(x)=x^\beta$, in Mytnik (2002) a weak solution to the
above SPDE was constructedand the pathwise uniqueness of the solution was left
as an open problem. In this paper we give an affirmative answer to this problem
for certain values of $\alpha$ and $\beta$. In particular, for $\alpha\beta=1$,
where the solution to the above equation is the density of a super-Brownian
motion with $\alpha$-stable branching (see also Mytnik (2002)), our result
leads to its pathwise uniqueness for $1<\alpha<\sqrt{5}-1$.
  The local H\"older continuity of the solution is also obtained in this paper
for fixed time $t>0$.


title:
Memory Efficient Decoders using Spatially Coupled Quasi-Cyclic LDPC
  Codes

abstract:
  In this paper we propose the construction of Spatially Coupled Low-Density
Parity-Check (SC-LDPC) codes using a periodic time-variant Quasi-Cyclic (QC)
algorithm. The QC based approach is optimized to obtain memory efficiency in
storing the parity-check matrix in the decoders. A hardware model of the
parity-check storage units has been designed for Xilinx FPGA to compare the
logic and memory requirements for various approaches. It is shown that the
proposed QC SC-LDPC code (with optimization) can be stored with reasonable
logic resources and without the need of block memory in the FPGA. In addition,
a significant improvement in the processing speed is also achieved.


title: Erasure/list exponents for Slepian-Wolf decoding

abstract:
  We analyze random coding error exponents associated with erasure/list
Slepian-Wolf decoding using two different methods and then compare the
resulting bounds. The first method follows the well known techniques of
Gallager and Forney and the second method is based on a technique of distance
enumeration, or more generally, type class enumeration, which is rooted in the
statistical mechanics of a disordered system that is related to the random
energy model (REM). The second method is guaranteed to yield exponent functions
which are at least as tight as those of the first method, and it is
demonstrated that for certain combinations of coding rates and thresholds, the
bounds of the second method are strictly tighter than those of the first
method, by an arbitrarily large factor. In fact, the second method may even
yield an infinite exponent at regions where the first method gives finite
values. We also discuss the option of variable-rate Slepian-Wolf encoding and
demonstrate how it can improve on the resulting exponents.


title:
Microscopic theory of the insulating electronic ground states of
  actinide dioxides AnO2 (An=U, Np, Pu, Am, and Cm)

abstract:
  The electronic ground states of the actinide dioxides AnO2 (with An=U, Np,
Pu, Am, and Cm) are investigated employing first-principles calculations within
the framework of the local density approximation +U (LDA+U) approach,
implemented in a full-potential linearized augmented plane-wave scheme. A
systematic analysis of the An-5f states is performed which provides intuitive
connections between the electronic structures and the local crystalline fields
of the f states in the AnO2 series. Particularly the mechanisms leading to the
experimentally observed insulating ground states are investigated. These are
found to be caused by the strong spin-orbit and Coulomb interactions of the 5f
orbitals; however, as a result of the different configurations, this mechanism
works in distinctly different ways for each of the AnO2 compounds. In agreement
with experimental observations, the nonmagnetic states of plutonium and curium
dioxide are computed to be insulating, whereas those of uranium, neptunium, and
americium dioxides require additional symmetry breaking to reproduce the
insulator ground states, a condition which is met with magnetic phase
transitions. We show that the occupancy of the An-f orbitals is closely
connected to each of the appearing insulating mechanisms. We furthermore
investigate the detailed constitution of the noncollinear multipolar moments
for transverse 3q magnetic ordered states in UO2 and longitudinal 3q high-rank
multipolar ordered states in NpO2 and AmO2.


title: Coherent \pi 0\eta\ photoproduction on s-shell nuclei

abstract:
  Coherent photoproduction of \pi 0\eta\ on the deuteron, He3 and He4 nuclei is
considered in the energy region from threshold to the lab photon energy 1.2
GeV. The transition amplitude is derived using impulse approximation. Effects
of pion absorption are included by means of the Fernbach-Serber-Taylor model.
Interaction of the produced \eta-mesons with the recoiled nucleus is taken into
account for the reactions on d and He3. The corresponding \eta d and \eta He3
scattering amplitudes are obtained as solutions of the few-body equations for
\eta NN and \eta-3N systems. Impact of this interaction on the differential
cross section in the region of small relative \eta-nuclear momenta is
discussed.


title: Stability of Anisotropic Cylinder with Zero Expansion

abstract:
  We study the dynamical instability of anisotropic collapsing cylinder with
the expansion-free condition, which generates vacuum cavity within fluid
distribution. The perturbation scheme is applied to distinguish Newtonian,
post-Newtonian and post-post Newtonian terms, which are used for constructing
dynamical equation at Newtonian and post-Newtonian regimes. We analyze the role
of pressure anisotropy and energy density inhomogeneity on the stability of
collapsing cylinder. It turns out that stability of the cylinder depends upon
these physical properties of the fluid, not on the stiffness of the fluid.


title:
Understanding angular momentum transport in red giants: the case of KIC
  7341231

abstract:
  Context. Thanks to recent asteroseismic observations, it has been possible to
infer the radial differential rotation profile of subgiants and red giants.
  Aims. We want to reproduce through modeling the observed rotation profile of
the early red giant KIC 7341231 and constrain the physical mechanisms
responsible for angular momentum transport in stellar interiors.
  Methods. We compute models of KIC 7341231 including a treatment of shellular
rotation and we compare the rotation profiles obtained with the one derived by
Deheuvels et al. (2012). We then modify some modeling parameters in order to
quantify their effect on the obtained rotation profile. Moreover, we mimic a
powerful angular momentum transport during the Main Sequence and study its
effect on the evolution of the rotation profile during the subgiant and red
giant phases.
  Results. We show that meridional circulation and shear mixing alone produce a
rotation profile for KIC 7341231 too steep compared to the observed one. An
additional mechanism is then needed to increase the internal transport of
angular momentum. We find that this undetermined mechanism has to be efficient
not only during the Main Sequence but also during the much quicker subgiant
phase. Moreover, we point out the importance of studying the whole rotational
history of a star in order to explain its rotation profile during the red giant
evolution.


title: Characterizing vortex beam with angular-double-slit interference

abstract:
  The Fraunhofer diffraction intensity distribution of Laguerre-Gaussian beam
is studied in an angular-double-slit interferometer. We demonstrate that the
spiral phase structure of vortex light can be clearly revealed in this
interference geometry, and it gives us an efficient way to distinguish
different order of Laguerre-Gaussian beams. This angular-double-slit
interference gives us a better understanding to the nature of orbital angular
momentum and the interpretation of vortex beams interference phenomenon.


title: Photometric study of an Eclipsing Binary in Praesepe

abstract:
  We present CCD photometric observations of an eclipsing binary in the
direction of the open cluster Praesepe using the 2 m telescope of IUCAA
Girawali Observatory, India. Though the system was classified as an eclipsing
binary by Pepper et al.(2008),detail investigations were lacking. The
photometric solutions using the Wilson-Devinney code suggest that it is a
W-type W UMa system and interestingly, the system parameters were similar to
another contact binary system SW Lac.


title:
Spin Hall effect in spin-valley coupled monolayer transition-metal
  dichalcogenides

abstract:
  We study both the intrinsic and extrinsic spin Hall effect in spin-valley
coupled monolayers of transition metal dichalcogenides. We find that whereas
the skew-scattering contribution is suppressed by the large band gap, the
side-jump contribution is comparable to the intrinsic one with opposite sign in
the presence of scalar and magnetic scattering. Intervalley scattering tends to
suppress the side-jump contribution due to the loss of coherence. By tuning the
ratio of intra- to intervalley scattering, the spin Hall conductivity shows a
sign change in hole-doped samples. Multiband effect in other doping regime is
considered, and it is found that the sign change exists in the heavily
hole-doped regime, but not in the electron-doped regime.


title: Proceedings 16th International Refinement Workshop

abstract:
  The 16th BCS-FACS Refinement Workshop was co-located with iFM 2013 held in
Turku, Finland on June 11th, 2013. This volume contains the 6 papers selected
for presentation at the workshop following a peer review process. The papers
cover a wide range of topics in the theory and application of refinement.
Refinement is one of the cornerstones of a formal approach to software
engineering: the process of developing a more detailed design or implementation
from an abstract specification through a sequence of mathematically-based steps
that maintain correctness with respect to the original specification.


title:
Locking Free Quadrilateral Continuous/Discontinuous Finite Element
  Methods for the Reissner-Mindlin Plate

abstract:
  We develop a finite element method with continuous displacements and
discontinuous rotations for the Mindlin-Reissner plate model on quadrilateral
elements. To avoid shear locking, the rotations must have the same polynomial
degree in the parametric reference plane as the parametric derivatives of the
displacements, and obey the same transformation law to the physical plane as
the gradient of displacements. We prove optimal convergence, uniformly in the
plate thickness, and provide numerical results that confirm our estimates.


title: Analysis of Three SU UMa-Type Dwarf Novae in the Kepler Field

abstract:
  We studied the Kepler light curves of three SU UMa-type dwarf novae. Both the
background dwarf nova of KIC 4378554 and V516 Lyr showed a combination of
precursor-main superoutburst, during which superhumps always developed on the
fading branch of the precursor. This finding supports the thermal-tidal
instability theory as the origin of the superoutburst. A superoutburst of V585
Lyr recorded by Kepler did not show a precursor outburst and the superhumps
developed only after the maximum light, a first example in the Kepler data so
far. Such a superoutburst is understood within the thermal-tidal instability
model. The observation of V585 Lyr made the first clear Kepler detection of the
positive period derivative commonly seen in the "stage B" superhumps in dwarf
novae with short orbital periods. In all objects, there was no strong signature
of a transition to the dominating stream impact-type component of superhumps,
suggesting that there is no strong indication of an enhanced mass-transfer
following the superoutburst. We have determined the orbital period of V516 Lyr
to be 0.083999(8) d. In V516 Lyr, some of outbursts were double outbursts in a
various degree. The preceding outburst in the double outburst was of the
inside-out nature while the following one was of the outside-in nature. One of
superoutbursts in V516 Lyr was preceded by a double precursor. The preceding
precursor failed to trigger a superoutburst and the following precursor
triggered a superoutburst by developing positive superhumps.


title:
Algebraic Net Class Rewriting Systems, Syntax and Semantics for
  Knowledge Representation and Automated Problem Solving

abstract:
  The intention of the present study is to establish general framework for
automated problem solving by approaching the task universal algebraically
introducing knowledge as realizations of generalized free algebra based nets,
graphs with gluing forms connecting in- and out-edges to nodes. Nets are caused
to undergo transformations in conceptual level by type wise differentiated
intervening net rewriting systems dispersing problems to abstract parts,
matching being determined by substitution relations. Achieved sets of
conceptual nets constitute congruent classes. New results are obtained within
construction of problem solving systems where solution algorithms are derived
parallel with other candidates applied to the same net classes. By applying
parallel transducer paths consisting of net rewriting systems to net classes
congruent quotient algebras are established and the manifested class rewriting
comprises all solution candidates whenever produced nets are in anticipated
languages liable to acceptance of net automata.


title:
Sharp comparison and maximum principles via horizontal normal mapping in
  the Heisenberg group

abstract:
  In this paper we solve a problem raised by Guti\'errez and Montanari about
comparison principles for $H-$convex functions on subdomains of Heisenberg
groups. Our approach is based on the notion of the sub-Riemannian horizontal
normal mapping and uses degree theory for set-valued maps. The statement of the
comparison principle combined with a Harnack inequality is applied to prove the
Aleksandrov-type maximum principle, describing the correct boundary behavior of
continuous $H-$convex functions vanishing at the boundary of horizontally
bounded subdomains of Heisenberg groups. This result answers a question by
Garofalo and Tournier. The sharpness of our results are illustrated by
examples.


title:
Scaling Radio Astronomy Signal Correlation on Heterogeneous
  Supercomputers Using Various Data Distribution Methodologies

abstract:
  Next generation radio telescopes will require orders of magnitude more
computing power to provide a view of the universe with greater sensitivity. In
the initial stages of the signal processing flow of a radio telescope, signal
correlation is one of the largest challenges in terms of handling huge data
throughput and intensive computations. We implemented a GPU cluster based
software correlator with various data distribution models and give a systematic
comparison based on testing results obtained using the Fornax supercomputer. By
analyzing the scalability and throughput of each model, optimal approaches are
identified across a wide range of problem sizes, covering the scale of next
generation telescopes.


title: On the post-quantum security of encrypted key exchange protocols

abstract:
  We investigate the post-quantum security of the encrypted key exchange(EKE)
protocols based on some basic physical parameters of ion-trap quantum computer,
and show that the EKE protocol with a 40-bit password will be secure against a
quantum adversary with several ion-trap quantum computers. We present a
password encrypted no-key protocol to resist middle-man attack, and prove that
it is also with the post-quantum security. The analysis presented here is
probably of general meaning for the security evaluation of various hybrid
cryptosystems.


title: Photometric redshifts for Quasars in multi band Surveys

abstract:
  MLPQNA stands for Multi Layer Perceptron with Quasi Newton Algorithm and it
is a machine learning method which can be used to cope with regression and
classification problems on complex and massive data sets. In this paper we give
the formal description of the method and present the results of its application
to the evaluation of photometric redshifts for quasars. The data set used for
the experiment was obtained by merging four different surveys (SDSS, GALEX,
UKIDSS and WISE), thus covering a wide range of wavelengths from the UV to the
mid-infrared. The method is able i) to achieve a very high accuracy; ii) to
drastically reduce the number of outliers and catastrophic objects; iii) to
discriminate among parameters (or features) on the basis of their significance,
so that the number of features used for training and analysis can be optimized
in order to reduce both the computational demands and the effects of
degeneracy. The best experiment, which makes use of a selected combination of
parameters drawn from the four surveys, leads, in terms of DeltaZnorm (i.e.
(zspec-zphot)/(1+zspec)), to an average of DeltaZnorm = 0.004, a standard
deviation sigma = 0.069 and a Median Absolute Deviation MAD = 0.02 over the
whole redshift range (i.e. zspec <= 3.6), defined by the 4-survey cross-matched
spectroscopic sample. The fraction of catastrophic outliers, i.e. of objects
with photo-z deviating more than 2sigma from the spectroscopic value is < 3%,
leading to a sigma = 0.035 after their removal, over the same redshift range.
The method is made available to the community through the DAMEWARE web
application.


title:
Blow-up solutions and peakons to a generalized $\mu$-Camassa-Holm
  integrable equation

abstract:
  Consideration here is a generalized $\mu$-type integrable equation, which can
be regarded as a generalization to both the $\mu$-Camassa-Holm and modified
$\mu$-Camassa-Holm equations. It is shown that the proposed equation is
formally integrable with the Lax-pair and the bi-Hamiltonian structure and its
scale limit is an integrable model of hydrodynamical systems describing short
capillary-gravity waves. Local well-posedness of the Cauchy problem in the
suitable Sobolev space is established by the viscosity method. Existence of
peaked traveling-wave solutions and formation of singularities of solutions for
the equation are investigated. It is found that the equation admits a single
peaked soliton and multi-peakon solutions. The effects of varying
$\mu$-Camassa-Holm and modified $\mu$-Camassa-Holm nonlocal nonlinearities on
blow-up criteria and wave breaking are illustrated in detail. Our analysis
relies on the method of characteristics and conserved quantities and is
proceeded with a priori differential estimates.


title:
The critical state in thin superconductors as a mixed boundary value
  problem: analysis and solution by means of the Erd\'elyi-Kober operators

abstract:
  With this paper we provide an effective method to solve a large class of
problems related to the electromagnetic behavior of thin superconductors. Here
all the problems are reduced to finding the weight functions for the Green
integrals that represent the magnetic field components; these latter must
satisfy the mixed boundary value conditions that naturally arise from the
critical state assumptions. The use of the Erd\'elyi-Kober operators and of the
Hankel transforms (and mostly the employment of their composition properties)
is the keystone to unify the method toward the solution. In fact, the procedure
consists always of the same steps and does not require any peculiar invention.
For this reason the method, here presented in detail for the simplest cases
that can be handled in analytical way (two parts boundary), can be directly
extended to many other more complex geometries (three or more parts), which
usually will require a numerical treatment. In this paper we use the operator
technique to derive the current density and field distributions in perfectly
conducting and superconducting thin discs and tapes subjected to a uniform
magnetic field or carrying a transport current. Although analytical expressions
for the field and current distributions have already been found by other
authors in the past by using several other methods, their derivation is often
cumbersome or missing key details, which makes it difficult for the reader to
fully understand the derivation of the analytical formulas and, more
importantly, to extend the same methods to solve similar new problems. On the
contrary, the characterization of these cases as mixed boundary conditions has
the advantage of referring to an immediate and na\"ive translation of physics
into a consistent mathematical formulation whose possible extension to other
cases is self-evident.


title:
Additional material on local limit theorem for finite Additive Markov
  Processes [HL13]

abstract:
  This paper proposes additional material to the main statements of [HL13]
which are are recalled in Section~2. In particular an application of
[Theorem~2.2,HL13] to Renewal Markov Processes is provided in Section~4 and a
detailed checking of the assumptions of [Theorem~2.2,HL13] for the joint
distribution of local times of a finite jump process is reported in Section~5.
A uniform version of [Theorem~2.2,HL13] with respect to a compact set of
transition matrices is given in Section~6 (see [Remark 2.4,HL13]). The basic
material on the semigroup of Fourier matrices and the spectral approach used in
[HL13] is recalled in Section~3 in order to obtain a good understanding of the
properties involved in this uniform version.


title: On complex line arrangements and their boundary manifolds

abstract:
  Let A be a line arrangement in the complex projective plane CP2. We define
and describe the inclusion map of the boundary manifold --the boundary of a
close regular neighborhood of A-- in the exterior of the arrangement. We obtain
two explicit descriptions of the map induced on the fundamental groups. These
computations provide a new minimal presentation of the fundamental group of the
complement.


title: A simple proof for the multivariate Chebyshev inequality

abstract:
  In this paper a simple proof of the Chebyshev's inequality for random vectors
obtained by Chen (arXiv:0707.0805v2, 2011) is obtained. This inequality gives a
lower bound for the percentage of the population of an arbitrary random vector
X with finite mean E(X) and a positive definite covariance matrix V=Cov(X)
whose Mahalanobis distance with respect to V to the mean E(X) is less than a
fixed value. The proof is based on the calculation of the principal components.


title: Impact on the power spectrum of Screening in Modified Gravity Scenarios

abstract:
  We study the effects of screened modified gravity of the $f(R)$, dilaton and
symmetron types on structure formation, from the quasi-linear to the non-linear
regime, using semi-analytical methods. For such models, where the range of the
new scalar field is typically within the Mpc range and below in the
cosmological context, non-linear techniques are required to understand the
deviations of the power spectrum of the matter density contrast compared to the
$\Lambda$-CDM template. This is nowadays commonly tackled using extensive
N-body simulations. Here we present new results combining exact perturbation
theory at the one loop level (and a partial resummation of the perturbative
series) with a halo model. The former allows one to extend the linear
perturbative analysis up to $k\lesssim 0.15{\rm h Mpc}^{-1}$ at the
perturbative level while the latter leads to a reasonable, up to a few percent,
agreement with numerical simulations for $k\lesssim 3{\rm h Mpc}^{-1}$ for
large curvature $f(R)$ models, and $k\lesssim 1{\rm h Mpc}^{-1}$ for dilatons
and symmetrons, at $z=0$. We also discuss how the behaviors of the perturbative
expansions and of the spherical collapse differ for $f(R)$, dilaton, and
symmetron models.


title:
Analysis of $\Lambda_{b}\to$ $p K^{-}$ and $p \pi^{-}$ decays in a
  flavor changing $Z^{\prime}$ model

abstract:
  In this paper, we calculate the branching ratios of \Lambda_{b} \to pK^{-}
and p\pi^{-} decays in the flavor changing Z^{\prime} model. We find that the
branching ratios for these two decay modes are sensitive to the contributions
of Z^{\prime} boson. For \Lambda_{b}\to p K^{-} decay, if the left-handed
couplings are equal to the right-handed couplings, the branching ratio of this
decay could match up to the currently experimental data for \xi_{s}=0.01 and
-52^{\circ}<\phi^{L}_{s}<132^{\circ}, or \xi_{s}=0.004 and
0^{\circ}<\phi^{L}_{s}<84^{\circ}; if only the left-handed couplings are
considered, it could match up to the experimental data for \xi_{s}=0.01 and
-10^{\circ}<\phi^{L}_{s}<138^{\circ}$. And for \Lambda_{b} \to p\pi^{-} decay,
if the left-handed and right-handed couplings are equal, the branching ratio of
\Lambda_{b} \to p\pi^{-} decay may be consistent with the currently
experimental data with \xi_{d}=0.05 and -135^{\circ}<\phi^{L}_{d}<43^{\circ},
if only the left-handed couplings are considered, it may be consistent with
\xi_{d}=0.05 and -114^{\circ}<\phi^{L}_{d}<8^{\circ}.


title: Optimal strategies for estimating the average fidelity of quantum gates

abstract:
  We show that the minimum experimental effort to characterize the proper
functioning of a quantum device scales as 2^n for n qubits and requires
classical computational resources ~ n^2 2^{3n}. This represents an exponential
reduction compared to the best currently available protocol, Monte Carlo
characterization. The reduction comes at the price of either having to prepare
entangled input states or obtaining bounds rather than the average fidelity
itself. It is achieved by applying Monte Carlo sampling to so-called
two-designs or two classical fidelities. For the specific case of Clifford
gates, the original version of Monte Carlo characterization based on the
channel-state isomorphism remains an optimal choice. We provide a
classification of the available efficient strategies for device
characterization in terms of the number of required experimental settings,
average number of actual measurements and classical computational resources.


title: Exploration-exploitation trade-off features a saltatory search behaviour

abstract:
  Searching experiments conducted in different virtual environments over a
gender balanced group of people revealed a gender irrelevant scale-free spread
of searching activity on large spatiotemporal scales. We have suggested and
solved analytically a simple statistical model of the coherent-noise type
describing the exploration-exploitation trade-off in humans ("should I stay or
should I go"). The model exhibits a variety of saltatory behaviours, ranging
from Levy flights occurring under uncertainty to Brownian walks performed by a
treasure hunter confident of the eventual success.


title:
A reduction theory for operators in type $\rm{I}_{n}$ von Neumann
  algebras

abstract:
  In this paper, we study the structure of operators in a type $\mathrm{I}_{n}$
von Neumann algebra $\mathscr{A}$. Inspired by the Jordan canonical form
theorem, our main motivation is to figure out the relation between the
structure of an operator $A$ in $\mathscr{A}$ and the property that a bounded
maximal abelian set of idempotents contained in the relative commutant
$\{A\}^{\prime} \cap\mathscr{A}$ is unique up to similarity. Furthermore, we
classify this class of operators with the property by $K$-theory for Banach
algebras. Some views and techniques are from von Neumann's reduction theory.


title:
El Triangulo de Platon y El Factor Gnomonico: Una aplicacion a los
  oraculos de Herodoto

abstract:
  A modification to the gnomonic factor using the concept of triangle of Plato
is presented. With the aid of the platonic gnomonic factor (fgp) as we called
it, we find that the oracles mentioned by Herodotus in his History, Dodona in
Greece and Ammon in Oasis Siwa, Libya, were placed there because the noon
shadow of Sun of a gnomon formed, back in 2500BC, the triangle of Plato the
former, and the Egyptian sacred triangle the latter. This means that both
concepts were known by Egyptians form Thebes long before they were formalized
by the Greeks. The right angled triangle concept is an idealization, as said by
D. Magdolen, of an astronomical observation; i. e. it is the shadow cast by a
gnomon.
  -----
  Se presenta una modificacion al factor gnomonico usando el concepto de
triangulo de Platon. Con la ayuda de lo que llamamos factor gnomonico platonico
(fgp) nosotros encontramos que los oraculos mencionados por Herodoto en su
Historia, Dodona en Grecia, y Ammon en el Oasis Siwa, Libia, fueron ubicados
ahi porque, hacia el anio 2500AC, la sombra proyectada por un gnomon vertical
formo el triangulo de Platon en el primero y el triangulo sagrado Egipcio el
ultimo. Esto significa que ambos conceptos eran conocidos por los Egipcios de
Tebas, a decir de Herodoto, bastante antes de estos fueran formalizados por los
griegos. El concepto de triangulo rectangulo seria la idealizacion, como dice
D. Magdolen, de una observacion astronomica; esto es, la proyeccion de la
sombra por un gnomon.


title: Geographica: A Benchmark for Geospatial RDF Stores

abstract:
  Geospatial extensions of SPARQL like GeoSPARQL and stSPARQL have recently
been defined and corresponding geospatial RDF stores have been implemented.
However, there is no widely used benchmark for evaluating geospatial RDF stores
which takes into account recent advances to the state of the art in this area.
In this paper, we develop a benchmark, called Geographica, which uses both
real-world and synthetic data to test the offered functionality and the
performance of some prominent geospatial RDF stores.


title:
Magnetic field amplification and evolution in turbulent collisionless
  MHD: an application to the ICM

abstract:
  The amplification and maintenance of the observed magnetic fields in the ICM
are usually attributed to the turbulent dynamo action. This is generally
derived employing a collisional MHD model. However, in the ICM the ion mean
free path between collisions is of the order of the dynamical scales, thus
requiring a collisionless MHD description. Unlike collisional MHD simulations,
our study uses an anisotropic plasma pressure with respect to the direction of
the local magnetic field, which brings the plasma within a parameter space
where collisionless instabilities should take place. Within the adopted model
these instabilities are contained at bay through the relaxation term of the
pressure anisotropy which simulates the feedback of the mirror and firehose
instabilities. This relaxation acts to get the plasma distribution function
consistent with the empirical studies of collisionless plasmas. Our 3D
numerical simulations of forced transonic turbulence motivated by modeling of
the turbulent ICM are performed for different initial values of the magnetic
field intensity, and different relaxation rates of the pressure anisotropy. We
found that in the high beta plasma regime corresponding to the ICM conditions,
a fast anisotropy relaxation rate gives results which are similar to the
collisional-MHD model as far as the statistical properties of the turbulence
are concerned. Also, the amplification of seed magnetic fields due to the
turbulent dynamo action is similar to the collisional-MHD model. Our
simulations that do not employ the anisotropy relaxation deviate significantly
from the collisional-MHD results, and show more power at the small-scale
fluctuations of both density and velocity representing the results of the
instabilities. For these simulations the large scale fluctuations in the
magnetic field are mostly suppressed and the turbulent dynamo fails in
amplifying seed magnetic fields.

categories: astro-ph.CO astro-ph.GA astro-ph.HE physics.plasm-ph


title:
Math-Net.Ru as a Digital Archive of the Russian Mathematical Knowledge
  from the XIX Century to Today

abstract:
  The main goal of the project Math-Net.Ru is to collect scientific
publications in Russian and Soviet mathematics journals since their foundation
to today and the authors of these publications into a single database and to
provide access to full-text articles for broad international mathematical
community. Leading Russian mathematics journals have been comprehensively
digitized dating back to the first volumes.


title:
To the problem of turbulence in quantitative easing transmission
  channels and transactions network channels at quantitative easing policy
  implementation by central banks

abstract:
  In agreement with the recent research findings in the econophysics, we
propose that the nonlinear dynamic chaos can be generated by the turbulent
capital flows in both the quantitative easing transmission channels and the
transaction networks channels, when there are the laminar turbulent capital
flows transitions in the financial system. We demonstrate that the capital
flows in both the quantitative easing transmission channels and the transaction
networks channels in the financial system can be accurately characterized by
the Reynolds numbers. We explain that the transition to the nonlinear dynamic
chaos regime can be realized through the cascade of the Landau, Hopf
bifurcations in the turbulent capital flows in both the quantitative easing
transmission channels and the transaction networks channels in the financial
system. We completed the computer modeling, using both the Nonlinear Dynamic
Stochastic General Equilibrium Theory (NDSGET) and the Hydrodynamics Theory
(HT), to accurately characterize the US economy in the conditions of the QE
policy implementation by the US Federal Reserve. We found that the ability of
the US financial system to adjust to the different levels of liquidity depends
on the nonlinearities appearance in the QE transmission channels, and is
limited by the laminar turbulent capital flows transitions in the QE
transmission channels and the transaction networks channels in the US financial
system. The proposed computer model allows us to make the accurate forecasts of
the US economy performance in the cases, when there are the different levels of
liquidity in the US financial system.


title:
Performance and Error Analysis of Knill's Postselection Scheme in a
  Two-Dimensional Architecture

abstract:
  Knill demonstrated a fault-tolerant quantum computation scheme based on
concatenated error-detecting codes and postselection with a simulated error
threshold of 3% over the depolarizing channel. %We design a two-dimensional
architecture for fault-tolerant quantum computation based on Knill's
postselection scheme. We show how to use Knill's postselection scheme in a
practical two-dimensional quantum architecture that we designed with the goal
to optimize the error correction properties, while satisfying important
architectural constraints. In our 2D architecture, one logical qubit is
embedded in a tile consisting of $5\times 5$ physical qubits. The movement of
these qubits is modeled as noisy SWAP gates and the only physical operations
that are allowed are local one- and two-qubit gates. We evaluate the practical
properties of our design, such as its error threshold, and compare it to the
concatenated Bacon-Shor code and the concatenated Steane code. Assuming that
all gates have the same error rates, we obtain a threshold of $3.06\times
10^{-4}$ in a local adversarial stochastic noise model, which is the highest
known error threshold for concatenated codes in 2D. We also present a Monte
Carlo simulation of the 2D architecture with depolarizing noise and we
calculate a pseudo-threshold of about 0.1%. With memory error rates one-tenth
of the worst gate error rates, the threshold for the adversarial noise model,
and the pseudo-threshold over depolarizing noise, are $4.06\times 10^{-4}$ and
0.2%, respectively. In a hypothetical technology where memory error rates are
negligible, these thresholds can be further increased by shrinking the tiles
into a $4\times 4$ layout.


title: Elastic scattering and path integral

abstract:
  Representation of the elastic scattering amplitude in the form of the path
integral is obtained using the stationary Schroedinger equation. A few methods
of evaluation of path integrals for large coupling constants are formulated.
The methods are based on the uncertainty correlation. The scattering lengths
and cross sections are calculated for the right angled and singular potentials
and the Yukawa potential. The comparison with exact results is made.


title: Solar Coronal Heating and Limb Effect

abstract:
  The quiet solar coronal heating problem and the observed center-to-limb
wavelength variations of the solar lines (limb effect) can be explained. In
this paper the quantitative calculations for these two phenomena are presented.


title:
Transformation between statistical ensembles in the modelling of nuclear
  fragmentation

abstract:
  We explore the conditions under which the particle number conservation
constraint deforms the predictions of fragmentation observables as calculated
in the grand canonical ensemble. We derive an analytical formula allowing to
extract canonical results from a grand canonical calculation and vice versa.
This formula shows that exact canonical results can be recovered for
observables varying linearly or quadratically with the number of particles,
independent of the grand canonical particle number fluctuations. We explore the
validity of such grand canonical extrapolation for different fragmentation
observables in the framework of the analytical Grand Canonical or Canonical
Thermodynamical Model [(G)CTM] of nuclear multifragmentation. It is found that
corrections to the grand canonical expectations can be evaluated with high
precision, provided the system does not experience a first order phase
transition. In particular, because of the Coulomb quenching of the liquid-gas
phase transition of nuclear matter, we find that mass conservation corrections
to the grand canonical ensemble can be safely computed for typical observables
of interest in experimental measurements of nuclear fragmentation, even if
deviations exist for highly exclusive observables.


title: Higher Nash blowup on normal toric varieties

abstract:
  The higher Nash blowup of an algebraic variety replaces singular points with
limits of certain spaces carrying higher order data associated to the variety
at non-singular points. In the case of normal toric varieties we give a
combinatorial description of the higher Nash blowup in terms of a Gr\"obner
fan. This description will allow us to prove the analogue of Nobile's theorem
on the usual Nash blowup in this context. More precisely, we prove that for a
normal toric variety, the higher Nash blowup is an isomorphism if and only if
the variety is non-singular.


title: Memory size bounds of prefix DAGs

abstract:
  In this report an entropy bound on the memory size is given for a compression
method of leaf-labeled trees. The compression converts the tree into a Directed
Acyclic Graph (DAG) by merging isomorphic subtrees.


title: Applications of Clifford's Geometric Algebra

abstract:
  We survey the development of Clifford's geometric algebra and some of its
engineering applications during the last 15 years. Several recently developed
applications and their merits are discussed in some detail. We thus hope to
clearly demonstrate the benefit of developing problem solutions in a unified
framework for algebra and geometry with the widest possible scope: from quantum
computing and electromagnetism to satellite navigation, from neural computing
to camera geometry, image processing, robotics and beyond.


title:
Arithmetic three-spheres theorems for quasilinear Riccati type
  inequalities

abstract:
  We consider arithmetic three-spheres inequalities to solutions of certain
second order quasilinear elliptic differential equations and inequalities with
a Riccati-type drift term.


title:
Validity of a clinical decision rule based alert system for drug dose
  adjustment in patients with renal failure intended to improve pharmacists'
  analysis of medication orders in hospitals

abstract:
  Objective: The main objective of this study was to assess the diagnostic
performances of an alert system integrated into the CPOE/EMR system for renally
cleared drug dosing control. The generated alerts were compared with the daily
routine practice of pharmacists as part of the analysis of medication orders.
Materials and Methods: The pharmacists performed their analysis of medication
orders as usual and were not aware of the alert system interventions that were
not displayed for the purpose of the study neither to the physician nor to the
pharmacist but kept with associate recommendations in a log file. A senior
pharmacist analyzed the results of medication order analysis with and without
the alert system. The unit of analysis was the drug prescription line. The
primary study endpoints were the detection of drug-dose prescription errors and
inter-rater reliability between the alert system and the pharmacists in the
detection of drug dose error. Results: The alert system fired alerts in 8.41%
(421/5006) of cases: 5.65% (283/5006) exceeds max daily dose alerts and 2.76%
(138/5006) under dose alerts. The alert system and the pharmacists showed a
relatively poor concordance: 0.106 (CI 95% [0.068, 0.144]). According to the
senior pharmacist review, the alert system fired more appropriate alerts than
pharmacists, and made fewer errors than pharmacists in analyzing drug dose
prescriptions: 143 for the alert system and 261 for the pharmacists. Unlike the
alert system, most diagnostic errors made by the pharmacists were false
negatives. The pharmacists were not able to analyze a significant number (2097;
25.42%) of drug prescription lines because understaffing. Conclusion: This
study strongly suggests that an alert system would be complementary to the
pharmacists activity and contribute to drug prescription safety.


title: Range-Renewal Speed and Entropy for I.I.D Models

abstract:
  In this note the relation between the range-renewal speed and entropy for
i.i.d. models is discussed.


title:
Direct Photon Production at RHIC and LHC-energies: Measured Data Versus
  a Model

abstract:
  We attempt, in this paper, to deal with the direct photon production
phenomena in $p+p$, $d+Au$ and $Au+Au$ collisions at RHIC energy,
$\sqrt{s_{NN}}$ = 200 GeV and in $Pb+Pb$-collisions at LHC energy,
$\sqrt{s_{NN}}$ = 2.76 TeV on the basis of a non-standard framework outlined in
the text. Comparisons of the model-based results with the measured data on some
observables reveal fair agreement; and they are modestly consistent with the
results obtained by some other models of `Standard' framework.


title: Particle Production in f(R) Gravity during Structure Formation

abstract:
  We study particle production in infrared-modified gravitational theories in
the contemporary universe. It is shown that in astronomical systems with rising
mass density, the curvature scalar may oscillate with very high frequency.
These oscillations lead to efficient particle production and in an interesting
range of model parameters could be a source of energetic cosmic rays. This
effect either excludes some models of modified gravity or suggests a new
mechanism of cosmic ray production.


title:
A basic class of symmetric orthogonal polynomials using the extended
  Sturm-Liouville theorem for symmetric functions

abstract:
  In this research, by applying the extended Sturm-Liouville theorem for
symmetric functions, a basic class of symmetric orthogonal polynomials (BCSOP)
with four free parameters is introduced and all its standard properties, such
as a generic second order differential equation along with its explicit
polynomial solution, a generic orthogonality relation, a generic three term
recurrence relation and so on, are presented. Then, it is shown that four main
sequences of symmetric orthogonal polynomials can essentially be extracted from
the introduced class. They are respectively the generalized ultraspherical
polynomials, generalized Hermite polynomials and two other sequences of
symmetric polynomials, which are finitely orthogonal on (-inf,inf) and can be
expressed in terms of the mentioned class directly. In this way, two
half-trigonometric sequences of orthogonal polynomials, as special sub-cases of
BCSOP, are also introduced.


title: What is Visualization Really for?

abstract:
  Whenever a visualization researcher is asked about the purpose of
visualization, the phrase "gaining insight" by and large pops out
instinctively. However, it is not absolutely factual that all uses of
visualization are for gaining a deep understanding, unless the term insight is
broadened to encompass all types of thought. Even when insight is the focus of
a visualization task, it is rather difficult to know what insight is gained,
how much, or how accurate. In this paper, we propose that "saving time" in
accomplishing a user's task is the most fundamental objective. By giving
emphasis to saving time, we can establish a concrete metric, alleviate
unnecessary contention caused by different interpretations of insight, and
stimulate new research efforts in some aspects of visualization, such as
empirical studies, design optimisation and theories of visualization.


title: New Physics Signatures in Kaon Decays

abstract:
  Kaon physics provides a unique opportunity to identify new flavour and CP
violating interactions beyond the Standard Model (SM). In the SM, implied by
the hierarchical structure of the CKM matrix and the GIM mechanism, flavour
changing neutral current processes are most strongly suppressed in the kaon
sector while the suppression is much less effective in the B meson systems.
Thus their theoretical cleanness makes rare K decays, in particular the K -> pi
nu anti-nu system, extremely well suited to look for deviations from their tiny
SM values. Despite the increasingly stringent constraints on new physics from
direct search experiments as well as indirect searches in B meson decays, large
enhancements of both K^+ -> pi^+ nu anti-nu and K_L -> pi^0 nu anti-nu are
still possible, and deviations from the SM could be observed even for a
multi-TeV new physics scale. In addition the correlation betweeen the charged
and neutral K -> pi nu anti-nu modes provides insight on the new physics
operator structure in K^0 - anti-K^0 mixing and its interplay with rare K
decays. Useful model-discriminating correlations exist also in the K_L -> pi^0
l^+ l^- system. Finally the K -> l nu decays provide a clean test of lepton
universality and place constraints on new physics complementary to the ones
obtained from the searches for charged lepton flavour violating decays.


title: EuFe2(As1-xPx)2: reentrant spin glass and superconductivity

abstract:
  By systematic investigations of the magnetic, transport and thermodynamic
properties of single crystals of EuFe2(As1-xPx)2 we explore the complex
interplay of superconductivity and Eu2+ magnetism. Below 30K, two magnetic
transitions are observed for all P substituted crystals suggesting a revision
of the phase diagram. In addition to the canted A-type antiferromagnetic order
of Eu2+ at approximately 20K, a spin glass transition is discovered at lower
temperatures. Most remarkably, the reentrant spin glass state of
EuFe2(As1-xPx)2 coexists with superconductivity around x = 0.2.