pinecone/core-2020-05-10-deduplication huggingface dataset:
Microstructural imaging of high repetition rate ultrafast laser written LiTaO3 waveguides

The microstructural changes associated with the formation of lithium tantalate waveguides after high repetition rate ultrafast laser inscription has been investigated by confocal micro-Raman experiments. While the laser beam focal volume is characterized by significant lattice damage, no reduction of Raman mode strength has been observed at the guiding region, suggesting the preservation of the nonlinear optical coefficient in the waveguide. A general blueshift of the Raman modes has been observed at the guiding region, suggesting lattice compression as the dominant mechanism of waveguide formation. © 2009 American Institute of Physics
Simultaneous multi-frequency observation of the unknown redshift blazar
  PG 1553+113 in March-April 2008

The blazar PG 1553+113 is a well known TeV gamma-ray emitter. In this paper,
we determine its spectral energy distribution using simultaneous
multi-frequency data in order to study its emission processes. An extensive
campaign was carried out between March and April 2008, where optical, X-ray,
high-energy (HE) gamma-ray, and very-high-energy (VHE) gamma-ray data were
obtained with the KVA, Abastumani, REM, RossiXTE/ASM, AGILE and MAGIC
telescopes, respectively. This is the first simultaneous broad-band (i.e.,
HE+VHE) gamma-ray observation, though AGILE did not detect the source. We
combine data to derive source's spectral energy distribution and interpret its
double peaked shape within the framework of a synchrotron self compton modelComment: 5 pages, 2 figures, publishe
Complete characterization and synthesis of the response function of
  elastodynamic networks

The response function of a network of springs and masses, an elastodynamic
network, is the matrix valued function $W(\omega)$, depending on the frequency
$\omega$, mapping the displacements of some accessible or terminal nodes to the
net forces at the terminals. We give necessary and sufficient conditions for a
given function $W(\omega)$ to be the response function of an elastodynamic
network, assuming there is no damping. In particular we construct an
elastodynamic network that can mimic a suitable response in the frequency or
time domain. Our characterization is valid for networks in three dimensions and
also for planar networks, which are networks where all the elements,
displacements and forces are in a plane. The network we design can fit within
an arbitrarily small neighborhood of the convex hull of the terminal nodes,
provided the springs and masses occupy an arbitrarily small volume.
Additionally, we prove stability of the network response to small changes in
the spring constants and/or addition of springs with small spring constants.Comment: 23 pages, 3 figure
A group model for stable multi-subject ICA on fMRI datasets

Spatial Independent Component Analysis (ICA) is an increasingly used
data-driven method to analyze functional Magnetic Resonance Imaging (fMRI)
data. To date, it has been used to extract sets of mutually correlated brain
regions without prior information on the time course of these regions. Some of
these sets of regions, interpreted as functional networks, have recently been
used to provide markers of brain diseases and open the road to paradigm-free
population comparisons. Such group studies raise the question of modeling
subject variability within ICA: how can the patterns representative of a group
be modeled and estimated via ICA for reliable inter-group comparisons? In this
paper, we propose a hierarchical model for patterns in multi-subject fMRI
datasets, akin to mixed-effect group models used in linear-model-based
analysis. We introduce an estimation procedure, CanICA (Canonical ICA), based
on i) probabilistic dimension reduction of the individual data, ii) canonical
correlation analysis to identify a data subspace common to the group iii)
ICA-based pattern extraction. In addition, we introduce a procedure based on
cross-validation to quantify the stability of ICA patterns at the level of the
group. We compare our method with state-of-the-art multi-subject fMRI ICA
methods and show that the features extracted using our procedure are more
reproducible at the group level on two datasets of 12 healthy controls: a
resting-state and a functional localizer study
$P$-parity of charm and strange particles in electroproduction
  processes, in collinear regime

We show that definite polarization observables for the simplest
electroproduction processes, $\ell+N\to \ell+B(1/2^\pm)+M(0^\pm)$,
$B=Y(\Lambda, \Sigma$ or $Y_c$-hyperon, $\Theta^+$-pentaquark) and $M=K$,
$\bar{K}$ or $D$, are sensitive to the relative P-parity $\pi(B)$ of the
NBM-system. The interference of the longitudinal and transversal amplitudes for
the collinear regime of the processes $\gamma^*+N\to B+M $($\gamma^*$ is the
virtual photon) - at any value of momentum transfer squared and excitation
energy of the $BM$-system - generates model independent relations between
analyzing powers (in unpolarized lepton scattering by polarized target), from
one side, and the components of the produced baryon $B$ polarization. It is
important to stress that these relations depend on the above mentioned
P-parity, and constitute a model independent method for the determination of
unknown parities of strange and charm particles.Comment: 4 page
Weinberg-Salam model at finite temperature and density

We present a new gauge fixing condition for the Weinberg-Salam electro-weak
theory at finite temperature and density.
  After spontaneous symmetry breaking occurs, every unphysical term in the
Lagrangian is eliminated with our gauge fixing condition. A new and simple
Lagrangian can be obtained where we can identify the propagators and vertices.
Some consequences are discussed, as the new gauge dependent masses of the gauge
fields and the new Faddeev-Popov Lagrangian. After obtaining the quadratic
terms, we calculate exactly the 1-loop effective potential identifying the
contribution of every particular field.Comment: 4 pages, no figures. New references added. Typo correcte
Diffusive scaling and the high-energy limit of deep inelastic scattering
  in QCD at large N_c

Within the limits of the large-N_c approximation (with N_c the number of
colors), we establish the high-energy behaviour of the diffractive and
inclusive cross-sections for deep inelastic scattering at fixed impact
parameter. We demonstrate that for sufficiently high energies and up to very
large values of Q^2, well above the proton average saturation momentum <Q_s^2>,
the cross-sections are dominated by dense fluctuations in the target
wavefunction, that is, by the relatively rare gluon configurations which are at
saturation on the resolution scale Q^2 of the virtual photon. This has
important physical consequences, like the emergence of a new, diffusive,
scaling, which replaces the `geometric scaling' property characteristic of the
mean field approximation. To establish this, we shall rely on a dipole version
of the Good-Walker formula for diffraction (that we shall derive here in the
context of DIS), together with the high-energy estimates for the dipole
scattering amplitudes which follow from the recently established evolution
equations with Pomeron loops and include the relevant fluctuations. We also
find that, as a consequence of fluctuations, the diffractive cross-section at
high energy is dominated by the elastic scattering of the quark-antiquark
component of the virtual photon, up to relatively large virtualities Q^2 >>
<Q_s^2>.Comment: 69 pages, 20 figure
The effect of episodic accretion on the phase transition of CO and CO_2
  in low-mass star formation

We study the evaporation and condensation of CO and CO_2 during the embedded
stages of low-mass star formation by using numerical simulations. We focus on
the effect of luminosity bursts, similar in magnitude to FUors and EXors, on
the gas-phase abundance of CO and CO_2 in the protostellar disk and infalling
envelope. The evolution of a young protostar and its environment is followed
based on hydrodynamical models using the thin-disk approximation, coupled with
a stellar evolution code and phase transformations of CO and CO_2. The
accretion and associated luminosity bursts in our model are caused by disk
gravitational fragmentation followed by quick migration of the fragments onto
the forming protostar. We found that bursts with luminosity on the order of
100-200 L_sun can evaporate CO ices in part of the envelope. The typical
freeze-out time of the gas-phase CO onto dust grains in the envelope (a few
kyr) is much longer than the burst duration (100-200 yr). This results in an
increased abundance of the gas-phase CO in the envelope long after the system
has returned into a quiescent stage. In contrast, luminosity bursts can
evaporate CO_2 ices only in the disk, where the freeze-out time of the
gas-phase CO_2 is comparable to the burst duration. We thus confirm that
luminosity bursts can leave long-lasting traces in the abundance of gas-phase
CO in the infalling envelope, enabling the detection of recent bursts as
suggested by previous semi-analytical studies.Comment: 12 pages, 6 figures, accepted for publication in Astronomy &
  Astrophysic
The Gaia-ESO Survey: metallicity of the Chamaeleon I star forming region

Context. Recent metallicity determinations in young open clusters and
star-forming regions suggest that the latter may be characterized by a slightly
lower metallicity than the Sun and older clusters in the solar vicinity.
However, these results are based on small statistics and inhomogeneous
analyses. The Gaia-ESO Survey is observing and homogeneously analyzing large
samples of stars in several young clusters and star-forming regions, hence
allowing us to further investigate this issue.
  Aims. We present a new metallicity determination of the Chamaeleon I
star-forming region, based on the products distributed in the first internal
release of the Gaia-ESO Survey.
  Methods. 48 candidate members of Chamaeleon I have been observed with the
high-resolution spectrograph UVES. We use the surface gravity, lithium line
equivalent width and position in the Hertzsprung-Russell diagram to confirm the
cluster members and we use the iron abundance to derive the mean metallicity of
the region.
  Results. Out of the 48 targets, we confirm 15 high probability members.
Considering the metallicity measurements for 9 of them, we find that the iron
abundance of Chamaeleon I is slightly subsolar with a mean value
[Fe/H]=-0.08+/-0.04 dex. This result is in agreement with the metallicity
determination of other nearby star-forming regions and suggests that the
chemical pattern of the youngest stars in the solar neighborhood is indeed more
metal-poor than the Sun. We argue that this evidence may be related to the
chemical distribution of the Gould Belt that contains most of the nearby
star-forming regions and young clusters.Comment: 13 pages, 11 figures, 3 tables, Accepted for publication in Astronomy
  & Astrophysic
Fractal analysis of the galaxy distribution in the redshift range 0.45 <
  z < 5.0

Evidence is presented that the galaxy distribution can be described as a
fractal system in the redshift range of the FDF galaxy survey. The fractal
dimension $D$ was derived using the FDF galaxy volume number densities in the
spatially homogeneous standard cosmological model with $\Omega_{m_0}=0.3$,
$\Omega_{\Lambda_0}=0.7$ and $H_0=70 \; \mbox{km} \; {\mbox{s}}^{-1} \;
{\mbox{Mpc}}^{-1}$. The ratio between the differential and integral number
densities $\gamma$ and $\gamma^\ast$ obtained from the red and blue FDF
galaxies provides a direct method to estimate $D$, implying that $\gamma$ and
$\gamma^\ast$ vary as power-laws with the cosmological distances. The
luminosity distance $d_{\scriptscriptstyle L}$, galaxy area distance
$d_{\scriptscriptstyle G}$ and redshift distance $d_z$ were plotted against
their respective number densities to calculate $D$ by linear fitting. It was
found that the FDF galaxy distribution is characterized by two single fractal
dimensions at successive distance ranges. Two straight lines were fitted to the
data, whose slopes change at $z \approx 1.3$ or $z \approx 1.9$ depending on
the chosen cosmological distance. The average fractal dimension calculated
using $\gamma^\ast$ changes from $\langle D \rangle=1.4^{\scriptscriptstyle
+0.7}_{\scriptscriptstyle -0.6}$ to $\langle D \rangle=0.5^{\scriptscriptstyle
+1.2}_{\scriptscriptstyle -0.4}$ for all galaxies, and $D$ decreases as $z$
increases. Small values of $D$ at high $z$ mean that in the past galaxies were
distributed much more sparsely and the large-scale galaxy structure was then
possibly dominated by voids. Results of Iribarrem et al. (2014,
arXiv:1401.6572) indicating similar fractal features with $\langle D \rangle
=0.6 \pm 0.1$ in the far-infrared sources of the Herschel/PACS evolutionary
probe (PEP) at $1.5 \lesssim z \lesssim 3.2$ are also mentioned.Comment: LaTex, 15 pages, 28 figures, 4 tables. To appear in "Physica A
Making Sense of Sunspot Decay; 2, Deviations from the Mean Law and Plage Effects

In a statistical analysis of Debrecen Photoheliographic Results sunspot area data we find that the logarithmic deviation (log D)' of the area decay rate D from the parabolic mean decay law (derived in the first paper in this series) follows a Gaussian probability distribution. As a consequence, the actual decay rate D and the its time average are also characterized by approximately lognormal distributions, as found in an earlier work. The correlation time of (log D)' is about 3 days. We find a significant physical anticorrelation between (log D)' and the amount of plage magnetic flux of the same polarity in an annulus around the spot on Kitt Peak magnetograms. The anticorrelation is interpreted in terms of a generalization of the turbulent erosion model of sunspot decay to the case when the flux tube is embedded in a preexisting homogeneous "plage" field. The decay rate is found to depend inversely on the value of this plage field, the relation being very close to logarithmic, i.e. the plage field acts as multiplicative noise in the decay process. A Gaussian probability distribution of the field strength in the surrounding plage will then naturally lead to a lognormal distribution of the decay rates, as observed. It is thus suggested that, beside other multiplicative noise sources, the environmental effect of surrounding plage fields is a major factor in the origin of lognormally distributed large random deviations from the mean law in the sunspot decay rates
Study of the fragmentation of $b$ quarks into $B$ mesons at the $Z$ peak

The fragmentation of b quarks into B mesons is studied with four million hadronic Z decays collected by the ALEPH experiment during the years 1991-1995. A semi-exclusive reconstruction of B->l nu D(*) decays is performed, by combining lepton candidates with fully reconstructed D(*) mesons while the neutrino energy is estimated from the missing energy of the event. The mean value of xewd, the energy of the weakly-decaying B meson normalised to the beam energy, is found to be mxewd = 0.716 +- 0.006 (stat) +- 0.006 \, (syst) using a model-independent method; the corresponding value for the energy of the leading B meson is mxel = 0.736 +- 0.006 (stat) +- 0.006 (syst). The reconstructed spectra are compared with different fragmentation models.The fragmentation of b quarks into B mesons is studied with four million hadronic Z decays collected by the ALEPH experiment during the years 1991-1995. A semi-exclusive reconstruction of B->l nu D(*) decays is performed, by combining lepton candidates with fully reconstructed D(*) mesons while the neutrino energy is estimated from the missing energy of the event. The mean value of xewd, the energy of the weakly-decaying B meson normalised to the beam energy, is found to be mxewd = 0.716 +- 0.006 (stat) +- 0.006 (syst) using a model-independent method; the corresponding value for the energy of the leading B meson is mxel = 0.736 +- 0.006 (stat) +- 0.006 (syst). The reconstructed spectra are compared with different fragmentation models.The fragmentation of b quarks into B mesons is studied with four million hadronic Z decays collected by the ALEPH experiment during the years 1991–1995. A semi-exclusive reconstruction of B →ℓ νD (★) decays is performed, by combining lepton candidates with fully reconstructed D (★) mesons while the neutrino energy is estimated from the missing energy of the event
Generation of entanglement in a system of two dipole-interacting atoms
  by means of laser pulses

Effectiveness of using laser field to produce entanglement between two
dipole-interacting identical two-level atoms is considered in detail. The
entanglement is achieved by driving the system with a carefully designed laser
pulse transferring the system's population to one of the maximally entangled
Dicke states in a way analogous to population inversion by a resonant
$\pi$-pulse in a two-level atom. It is shown that for the optimally chosen
pulse frequency, power and duration, the fidelity of generating a maximally
entangled state approaches unity as the distance between the atoms goes to
zero.Comment: 4 pages, 3 figures; submitted to the proceedings of the III Adriatico
  Research Conference on Quantum Interferometry, ICTP, March 1-5,1999; replaced
  with the final submitted versio
Quantum tomography of the GHZ state

We present a method of generation of the Greenberger-Horne-Zeilinger state
involving type II and type I parametric downconversion, and triggering
photodetectors. The state generated by the proposed experimental set-up can be
reconstructed through multi-mode quantum homodyne tomography. The feasibility
of the measurement is studied on the basis of Monte-Carlo simulations.Comment: Paper submitted to the proceedings of the III Adriatico Research
  Conference on Quantum Interferometry, ICTP, March 1-5,1999. 5 pages, 3 eps
  figure
Do banks really monitor? Evidence from CEO succession decisions

We demonstrate that banks play an important monitoring role in CEO succession that is not observed for other types of lenders, particularly public bondholders. There is a stronger relation between cash flow performance and forced CEO turnover for firms issuing bank debt during the year of CEO turnover than for firms not issuing bank debt, and bank debt issuance increases the likelihood of external CEO succession. The stock price reaction to CEO succession is higher when bank monitoring is prevalent. Our results are consistent with theories of relationship banking that propose a valuable monitoring role for well informed, incentivized bank lenders
Measurement of the Z boson differential cross section in transverse
  momentum and rapidity in proton-proton collisions at 8 TeV

We present a measurement of the Z boson differential cross section in
rapidity and transverse momentum using a data sample of pp collision events at
a centre-of-mass energy sqrt(s)=8 TeV, corresponding to an integrated
luminosity of 19.7 inverse femtobarns. The Z boson is identified via its decay
to a pair of muons. The measurement provides a precision test of quantum
chromodynamics over a large region of phase space. In addition, due to the
small experimental uncertainties in the measurement the data has the potential
to constrain the gluon parton distribution function in the kinematic regime
important for Higgs boson production via gluon fusion. The results agree with
the next-to-next-to-leading-order predictions computed with the FEWZ program.
The results are also compared to the commonly used leading-order MADGRAPH and
next-to-leading-order POWHEG generators.Comment: Replaced with published version. Added journal reference and DO
Electronic stress tensor analysis of molecules in gas phase of CVD
  process for GeSbTe alloy

We analyze the electronic structure of molecules which may exist in gas phase
of chemical vapor deposition process for GeSbTe alloy using the electronic
stress tensor, with special focus on the chemical bonds between Ge, Sb and Te
atoms. We find that, from the viewpoint of the electronic stress tensor, they
have intermediate properties between alkali metals and hydrocarbon molecules.
We also study the correlation between the bond order which is defined based on
the electronic stress tensor, and energy-related quantities. We find that the
correlation with the bond dissociation energy is not so strong while one with
the force constant is very strong. We interpret these results in terms of the
energy density on the "Lagrange surface", which is considered to define the
boundary surface of atoms in a molecule in the framework of the electronic
stress tensor analysis.Comment: 32 pages, 9 figure
Intersecting $P$-free families

We study the problem of determining the size of the largest intersecting
$P$-free family for a given partially ordered set (poset) $P$. In particular,
we find the exact size of the largest intersecting $B$-free family where $B$ is
the butterfly poset and classify the cases of equality. The proof uses a new
generalization of the partition method of Griggs, Li and Lu. We also prove
generalizations of two well-known inequalities of Bollob\'{a}s and Greene,
Katona and Kleitman in this case. Furthermore, we obtain a general bound on the
size of the largest intersecting $P$-free family, which is sharp for an
infinite class of posets originally considered by Burcsi and Nagy, when $n$ is
odd. Finally, we give a new proof of the bound on the maximum size of an
intersecting $k$-Sperner family and determine the cases of equality.Comment: Improved the writing following the suggestions of referees. Published
  version available via
  http://www.sciencedirect.com/science/article/pii/S009731651730047
Recovering star formation histories: Integrated-light analyses vs
  stellar colour-magnitude diagrams

Accurate star formation histories (SFHs) of galaxies are fundamental for
understanding the build-up of their stellar content. However, the most accurate
SFHs - those obtained from colour-magnitude diagrams (CMDs) of resolved stars
reaching the oldest main sequence turnoffs (oMSTO) - are presently limited to a
few systems in the Local Group. It is therefore crucial to determine the
reliability and range of applicability of SFHs derived from integrated light
spectroscopy, as this affects our understanding of unresolved galaxies from low
to high redshift.
  To evaluate the reliability of current full spectral fitting techniques in
deriving SFHs from integrated light spectroscopy by comparing SFHs from
integrated spectra to those obtained from deep CMDs of resolved stars.
  We have obtained a high signal--to--noise (S/N $\sim$ 36.3 per \AA)
integrated spectrum of a field in the bar of the Large Magellanic Cloud (LMC)
using EFOSC2 at the 3.6 meter telescope at La Silla Observatory. For this same
field, resolved stellar data reaching the oMSTO are available. We have compared
the star formation rate (SFR) as a function of time and the age-metallicity
relation (AMR) obtained from the integrated spectrum using {\tt STECKMAP}, and
the CMD using the IAC-star/MinnIAC/IAC-pop set of routines. For the sake of
completeness we also use and discuss other synthesis codes ({\tt STARLIGHT} and
{\tt ULySS}) to derive the SFR and AMR from the integrated LMC spectrum.
  We find very good agreement (average differences $\sim$ 4.1 $\%$) between the
SFR(t) and the AMR obtained using {\tt STECKMAP} on the integrated light
spectrum, and the CMD analysis. {\tt STECKMAP} minimizes the impact of the
age-metallicity degeneracy and has the advantage of preferring smooth solutions
to recover complex SFHs by means of a penalized $\chi^2$. [abridged]Comment: 23 pages, 24 figures. Accepted for publication in A&A (6 Sep 2015