pinecone/core-2020-05-10-deduplication huggingface dataset:
Petrological Study as a Tool to Evaluate the\ud
Degradation of Speleothems in Touristic Caves,\ud
Castafiar de Ibor Cave, Caceres, Spain

In Castafiar cave the surface of most of the speleothems present dissolution\ud
and corrosion features. In touristic caves, this process has usually been related to\ud
the acidification of the atmospheric moisture caused by C02 from the breath of\ud
visitors. However, in Castafiar cave the process of corrosion has been also observed\ud
in rooms that are not visited by tourists. Petrological studies were carried out in\ud
the speleothems affected by surface corrosion in Castafiar cave. The results indicate\ud
that this process occurs not only at present time, but over a period of thousands of\ud
years, as evidenced by the presence of corrosion lines inside and on the surface of\ud
the speleothems. All this and the fact that Castafiar cave recovers very quickly from\ud
changes in the environmental parameters, indicates that the dissolution-corrosion\ud
process is slow and hence it is not related to the presence of visitors
Equality of ordinary and symbolic powers of Stanley-Reisner ideals

This paper studies properties of simplicial complexes for which the m-th
symbolic power of the Stanley-Reisner ideal equals to the m-th ordinary power
for a given m > 1. The main results are combinatorial characterizations of such
complexes in the two-dimensional case. It turns out that there exist only a
finite number of complexes with this property and that these complexes can be
described completely. As a consequence we are able to determine all complexes
for which the m-th ordinary power of the Stanley-Reisner ideal is
Cohen-Macaulay for a given m > 1.Comment: 19 page
Numerical Computations with H(div)-Finite Elements for the Brinkman
  Problem

The H(div)-conforming approach for the Brinkman equation is studied
numerically, verifying the theoretical a priori and a posteriori analysis in
previous work of the authors. Furthermore, the results are extended to cover a
non-constant permeability. A hybridization technique for the problem is
presented, complete with a convergence analysis and numerical verification.
Finally, the numerical convergence studies are complemented with numerical
examples of applications to domain decomposition and adaptive mesh refinement.Comment: Minor clarifications, added references. Reordering of some figures.
  To appear in Computational Geosciences, final article available at
  http://www.springerlink.co
Low Temperature Behavior of the Thermopower in Disordered Systems near
  the Anderson Transition

We investigate the behavior of the thermoelectric power [S] in disordered
systems close to the Anderson-type metal-insulator transition [MIT] at low
temperatures. In the literature, we find contradictory results for S. It is
either argued to diverge or to remain a constant as the MIT is approached. To
resolve this dilemma, we calculate the number density of electrons at the MIT
in disordered systems using an averaged density of states obtained by
diagonalizing the three-dimensional Anderson model of localization. From the
number density we obtain the temperature dependence of the chemical potential
necessary to solve for S. Without any additional approximation, we use the
Chester-Thellung-Kubo-Greenwood formulation and numerically obtain the behavior
of S at low T as the Anderson transition is approached from the metallic side.
We show that indeed S does not diverge.Comment: 6 pages, 4 eps figures, to appear in Proceedings PILS'98 in Ann.
  Physik Leipzig 199
Rapidity-Alignment and p_T Compensation of Particle Pairs in Hadronic Z0
  Decays

Observation is made of rapidity-alignment of K+K- and ppbar pairs which
results from their asymmetric orientation in rapidity, with respect to the
direction from primary quark to antiquark. The K+K- and ppbar data are
consistent with predictions from the fragmentation string model. However, the
ppbar data strongly disagree with the conventional implementation of the
cluster model. The non-perturbative process of `gluon splitting to diquarks'
has to be incorporated into the cluster model for it to agree with the data.
Local conservation of p_T between particles nearby in rapidity (i.e., p_T
compensation) is analysed with respect to the thrust direction for pi+pi-,
K+K-, and ppbar pairs. In this case, the string model provides fair agreement
with the data. The cluster model is incompatible with the data for all three
particle pairs. The model with its central premiss of isotropically-decaying
clusters predicts a p_T correlation not seen in the data.Comment: 15 pages, 5 figures, Accepted by Phys. Lett.
Search for Low Scale Gravity Effects in e+e- Collisions at LEP

Recent theories propose that quantum gravity effects may be observable at LEP
energies via gravitons that couple to Standard Model particles and propagate
into extra spatial dimensions. The associated production of a graviton and a
photon is searched for as well as the effects of virtual graviton exchange in
the processes: e+e- -> gamma gamma, ZZ, WW, mu mu, tau tau, qq and ee No
evidence for this new interaction is found in the data sample collected by the
L3 detector at LEP at centre-of-mass energies up to 183 GeV. Limits close to 1
TeV on the scale of this new scenario of quantum gravity are set
The gauged Nambu - Jona Lasinio model: a mean field calculation with non
  mean field exponents

We analyse the phase diagram of the lattice gauged Nambu-Jona Lasinio model
with the help of a mean field approximation plus numerical simulations. We find
a phase transition line in the coupling parameters space separating the
chirally broken phase from the symmetric phase, which is in good qualitative
agreement with results obtained in the quenched-ladder approximation. The mean
field approximation relates the critical exponents along the continuous phase
transition line with the mass dependence of the chiral condensate in the
Coulomb phase of standard noncompact $QED$. Our numerical results for
noncompact $QED$ strongly suggest non mean field exponents along the critical
line.Comment: 11 pages, figures on reques
Poles of light resonances from unitarized Chiral perturbation Theory and
  their large Nc behavior

We have recently completed the one loop calculation of meson-meson scattering
within Chiral Perturbation Theory. Once unitarized, these amplitudes provide
simultaneously a remarkable description of the resonance region up to 1.2 GeV
as well as the low energy region, respecting the chiral symmetry expansion. The
position of the poles in these amplitudes is related to the mass and width of
the associated resonances that are generated without being explicitly included
in the Lagrangian. The spectroscopic nature of these states can then be deduced
by studying the behavior of these poles, through the Nc dependence of the
Chiral Perturbation Theory parameters, which can be obtained from QCD in the
large Nc limit.Comment: Invited talk to the 25th MRST, Conference on High Energy Physics
  (``J. Schechter Fest''). May 13 - 15, 2003, Syracuse University, Syracuse,
  New York. 13 pages, 2 figure
Shear viscosity of neutron-rich nucleonic matter near its liquid-gas
  phase transition

Within a relaxation time approach using free nucleon-nucleon cross sections
modified by the in-medium nucleon masses that are determined from an isospin-
and momentum-dependent effective nucleon-nucleon interaction, we investigate
the specific shear viscosity ($\eta/s$) of neutron-rich nucleonic matter near
its liquid-gas phase transition. It is found that as the nucleonic matter is
heated at fixed pressure or compressed at fixed temperature, its specific shear
viscosity shows a valley shape in the temperature or density dependence, with
the minimum located at the boundary of the phase transition. Moreover, the
value of $\eta/s$ drops suddenly at the first-order liquid-gas phase transition
temperature, reaching as low as $4\sim5$ times the KSS bound of $\hbar/4\pi$.
However, it varies smoothly for the second-order liquid-gas phase transition.
Effects of the isospin degree of freedom and the nuclear symmetry energy on the
value of $\eta/s$ are also discussed.Comment: 6 pages, 5 figure
Lax matrix solution of c=1 Conformal Field Theory

To a correlation function in a two-dimensional conformal field theory with
the central charge $c=1$, we associate a matrix differential equation $\Psi' =
L \Psi$, where the Lax matrix $L$ is a matrix square root of the
energy-momentum tensor. Then local conformal symmetry implies that the
differential equation is isomonodromic. This provides a justification for the
recently observed relation between four-point conformal blocks and solutions of
the Painlev\'e VI equation. This also provides a direct way to compute the
three-point function of Runkel-Watts theory -- the common $c\rightarrow 1$
limit of Minimal Models and Liouville theory.Comment: 20 pages, v3: Corrected sign mistakes in eqs. (4.35), (4.37), (4.42),
  (4.45) and (4.52). Conclusions unchange
Landau level transitions indoped graphene in a time dependent magnetic
  field

The aim of this work is to describe the Landau levels transitions of Bloch
electrons in doped graphene with an arbitrary time dependent magnetic field in
the long wavelength approximation. In particular, transitions from the m Landau
level to the m + 1 and m + 2 Landau levels are studied using time-dependent
perturbation theory. Time intervals are computed in which transition
probabilities tend to zero at low order in the coupling constant. In
particular, Landau level transitions are studied in the case of Bloch electrons
travelling in the direction of the applied magnetic force and the results are
compared with classical and revival periods of electrical current in graphene.
Finally, current probabilities are computed for the n = 0 and n = 1 Landau
levels showing expected oscillating behavior with modified cyclotron frequency.Comment: 18 pages, 7 figure
Modeling of the Radio Emission from the Vela Supernova Remnant

Supernova remnants (SNRs) are widely considered to be sites of Galactic
cosmic ray (CR) acceleration. Vela is one of the nearest Galactic composite
SNRs to Earth accompanied by the Vela pulsar and its pulsar wind nebula (PWN)
Vela X. The Vela SNR is one of the most studied remnants and it benefits from
precise estimates of various physical parameters such as distance and age.
Therefore, it is a perfect object for a detailed study of physical processes in
SNRs. The Vela SNR expands into the highly inhomogeneous cloudy interstellar
medium (ISM) and its dynamics is determined by the heating and evaporation of
ISM clouds. It features an asymmetrical X-ray morphology which is explained by
the expansion into two media with different densities. This could occur if the
progenitor of the Vela SNR exploded close to the edge of the stellar wind
bubble of the nearby Wolf-Rayet star $\gamma^2$Velorum and hence one part of
the remnant expands into the bubble. The interaction of the ejecta and the main
shock of the remnant with ISM clouds causes formation of secondary shocks at
which additional particle acceleration takes place. This may lead to the close
to uniform distribution of relativistic particles inside the remnant. We
calculate the synchrotron radio emission within the framework of the new
hydrodynamical model which assumes the supernova explosion at the edge of the
stellar wind bubble. The simulated radio emission agrees well with both the
total radio flux from the remnant and the complicated radio morphology of the
source.Comment: 8 pages, 5 figures, 2 tables, accepted for publication in A&
The VLT/NaCo large program to probe the occurrence of exoplanets and
  brown dwarfs at wide orbits: II- Survey description, results and performances

In anticipation of the VLT/SPHERE planet imager guaranteed time programs, we
have conducted a preparatory survey of 86 stars between 2009 and 2013 in order
to identify new faint comoving companions to ultimately carry out a
comprehensive analysis of the occurence of giant planets and brown dwarf
companions at wide (10-2000 AU) orbits around young, solar-type stars. We used
NaCo at VLT to explore the occurrence rate of giant planets and brown dwarfs
between typically 0.1 and 8''. Diffraction-limited observations in H-band
combined with angular differential imaging enabled us to reach primary
star-companion brightness ratios as small as 10-6 at 1.5''. 12 systems were
resolved as new binaries, including the discovery of a new white dwarf
companion to the star HD8049. Around 34 stars, at least one companion candidate
was detected in the observed field of view. More than 400 faint sources were
detected, 90% of them in 4 crowded fields. With the exception of HD8049B, we
did not identify any new comoving companions. The survey also led to spatially
resolved images of the thin debris disk around HD\,61005 that have been
published earlier. Finally, considering the survey detection limits, we derive
a preliminary upper limit on the frequency of giant planets for semi-major axes
of [10,2000] AU: typically less than 15% between 100 and 500 AU, and less than
10% between 50 and 500 AU for exoplanets more massive than 5 MJup and 10 MJup
respectively, considering a uniform input distribution and with a confidence
level of 95%.Comment: 19 pages, 8 figures, 12 Tables, accepted to A&
A Non-Trivial Zero Length Limit of the Nambu-Goto String

We show that a Nambu-Goto string has a nontrivial zero length limit which
corresponds to a massless particle with extrinsic curvature. The system has the
set of six first class constraints, which restrict the phase space variables so
that the spin vanishes. Upon quantization, we obtain six conditions on the
state, which can be represented as a wave function of position coordinates,
$x^\mu$, and velocities, $q^\mu$. We have found a wave function $\psi(x,q)$
that turns out to be a general solution of the corresponding system of six
differential equations, if the dimensionality of spacetime is eight. Though
classically the system is just a point particle with vanishing extrinsic
curvature and spin, the quantized system is not trivial, because it is
consistent in eight, but not in arbitrary, dimensions.Comment: 13 pages; Improved Section
Stellar physical parameters from Str \"omgren photometry. Application to
  the young stars in the Galactic anticenter survey

Aims. The aim is to derive accurate stellar distances and extinctions for
young stars of our survey in the Galactic anticenter direction using the
Str\"omgren photometric system. This will allow a detailed mapping of the
stellar density and absorption toward the Perseus arm. Methods. We developed a
new method for deriving physical parameters from Str\"omgren photometry and
also implemented and tested it. This is a model-based method that uses the most
recent available stellar atmospheric models and evolutionary tracks to
interpolate in a 3D grid of the unreddened indexes [m1], [c1] and Hbeta.
Distances derived from both this method and the classical pre-Hipparcos
calibrations were tested against Hipparcos parallaxes and found to be accurate.
Results. Systematic trends in stellar photometric distances derived from
empirical calibrations were detected and quantified. Furthermore, a shift in
the atmospheric grids in the range Teff=[7000,9000]K was detected and a
correction is proposed. The two methods were used to compute distances and
reddening for about 12000 OBA-type stars in our Str\"omgren anticenter survey.
Data from the IPHAS and 2MASS catalogs were used to complement the detection of
emission line stars and to break the degeneracy between early and late
photometric regions. We note that photometric distances can differ by more than
20%, those derived from the empirical calibrations being smaller than those
derived with the new method, which agree better with the Hipparcos data.Comment: 13 pages, 15 figure
Compact analytical form for non-$\zeta$ terms in critical exponents at order $1/N^3$

We simplify, to a single integral of dilogarithms, the least tractable O(1/N^3) contribution to the large-N critical exponent $\eta$ of the non-linear sigma-model, and hence $\phi^4$-theory, for any spacetime dimensionality, D. It is the sole generator of irreducible multiple zeta values in epsilon-expansions with $D=2-2\epsilon$, for the sigma-model, and $D=4-2\epsilon$, for $\phi^4$-theory. In both cases we confirm results of Broadhurst, Gracey and Kreimer (BGK) that relate knots to counterterms. The new compact form is much simpler than that of BGK. It enables us to develop 8 new terms in the epsilon-expansion with $D=3-2\epsilon$. These involve alternating Euler sums, for which the basis of irreducibles is larger. We conclude that massless Feynman diagrams in odd spacetime dimensions share the greater transcendental complexity of massive diagrams in even dimensions, such as those contributing to the electron's magnetic moment and the electroweak $\rho$-parameter. Consequences for the perturbative sector of Chern-Simons theory are discussed
Analytic tools to brane technology in N=2 gauge theories with matter

Exact solutions to the low-energy effective action (LEEA) of the four-dimensional N=2 supersymmetric gauge field theories are known to be obtained either by quantum field theory methods from S-duality in the Seiberg-Witten approach, or by the Type-IIA superstring/M-Theory methods of brane technology. After a brief review of the standard field-theoretical results for the N=2 gauge (Seiberg-Witten) LEEA, we consider a field-theoretical derivation of the exact hypermultiplet LEEA by using the N=2 harmonic superspace methods. We illustrate our techniques on a number of explicit examples. Our main purpose, however, is to discuss the existing analytical (calculational) support for the alternative methods of brane technology. We summarize known exact solutions to the eleven-dimensional and ten-dimensional type-IIA supergravities, which describe classical configurations of intersecting BPS branes with eight supercharges relevant to the non-perturbative N=2 gauge field theory with fundamental hypermultiplet matter. The crucial role of M-Theory in providing a classical resolution of singularities in the ten-dimensional (Type-IIA superstring) brane picture, as well as the N=2 extended supersymmetry in four dimensions, are made manifest. The two approaches to a derivation of the exact N=2 gauge theory LEEA are thus seen to be complementary to each other and mutually dependent
Dynamical generation of gauge and Higgs bosons in N=2 supersymmetric non-linear $\sigma$-models

A four-dimensional N=2 supersymmetric non-linear sigma-model with the Eguchi-Hanson (ALE) target space and a non-vanishing central charge is rewritten to a classically equivalent and formally renormalizable gauged `linear' sigma-model over a non-compact coset space in N=2 harmonic superspace by making use of an N=2 vector gauge superfield as the Lagrange multiplier. It is then demonstrated that the N=2 vector gauge multiplet becomes dynamical after taking into account one-loop corrections due to quantized hypermultiplets. This implies the appearance of a composite gauge boson, a composite chiral spinor doublet and a composite complex Higgs particle, all defined as the physical states associated with the propagating N=2 vector gauge superfield. The composite N=2 vector multiplet is further identified with the zero modes of a superstring ending on a D-6-brane. Some non-perturbative phenomena, such as the gauge symmetry enhancement for coincident D-6-branes and the Maldacena conjecture, turn out to be closely related to our NLSM via M-theory. Our results support a conjecture about the composite nature of superstrings ending on D-branes
Constituent Quark Model Calculation for a possible J^P=0^-,T=0 Dibaryon

There exists experimental evidence that a dibaryon resonance d' with quantum
numbers J^P=0^-,T=0 and mass 2065 MeV could be the origin of the narrow peak in
the (\pi^+ ,\pi^- ) double charge exchange cross--sections on nuclei. We
investigate the six--quark system with these quantum--numbers within the
constituent quark model, with linear confinement, effective one--gluon exchange
at short range and chiral interactions between quarks (\pi and \sigma
exchange). We classify all possible six quark states with J^P=0^-,T=0, and with
N=1 and N=3 harmonic oscillator excitations, using different reduction chains.
The six--quark Hamiltonian is diagonalized in the basis including the unique
N=1 state and the 10 most important states from the N=3 shell. We find, that
with most of the possible sets of parameters, the mass of such a "dibaryon"
lies above the N(939)+N^\ast(1535) threshold. The only possibility to describe
the supposed d'(2065) in the present context is to reduce the confinement
strength to very small values, however at the expense of describing the
negative parity resonances N^\ast. We also analyze the J^P=0^-,T=2,N=1
six--quark state.Comment: 42 pages, Latex, submitted to Nucl.Phys.
Nucleon Structure Functions at Moderate Q**2: Relativistic Constituent
  Quarks and Spectator Mass Spectrum

We present a model description of the nucleon valence structure function
applicable over the entire region of the Bjorken variable x, and above moderate
values of Q**2 (> 1 GeV**2). We stress the importance of describing the
complete spectrum of intermediate states which are spectator to the
deep-inelastic collision. At a scale of 1 GeV**2 the relevant degrees of
freedom are constituent quarks and pions. The large-x region is then described
in terms of scattering from constituent quarks in the nucleon, while the
dressing of constituent quarks by pions plays an important role at intermediate
x values. The correct small-x behavior, which is necessary for the proper
normalization of the valence distributions, is guaranteed by modeling the
asymptotic spectator mass spectrum according to Regge phenomenology.Comment: 44 pages RevTeX, 9 uuencoded figures, accepted for publication in
  Nucl. Phys.
PS1-10afx at z= 1.388: Pan-STARRS1 Discovery of a New Type of Superluminous Supernova

We present the Pan-STARRS1 discovery of PS1-10afx, a unique hydrogen-deficient superluminous supernova (SLSN) at redshift z = 1.388. The light curve peaked at z P1 = 21.7 mag, making PS1-10afx comparable to the most luminous known SNe, with Mu = –22.3 mag. Our extensive optical and near-infrared observations indicate that the bolometric light curve of PS1-10afx rose on the unusually fast timescale of ~12 days to the extraordinary peak luminosity of 4.1 × 1044 erg s–1 (M bol = –22.8 mag) and subsequently faded rapidly. Equally important, the spectral energy distribution is unusually red for an SLSN, with a color temperature of ~6800 K near maximum light, in contrast to previous hydrogen-poor SLSNe, which are bright in the ultraviolet (UV). The spectra more closely resemble those of a normal SN Ic than any known SLSN, with a photospheric velocity of ~11, 000 km s–1 and evidence for line blanketing in the rest-frame UV. Despite the fast rise, these parameters imply a very large emitting radius (gsim 5 × 1015 cm). We demonstrate that no existing theoretical model can satisfactorily explain this combination of properties: (1) a nickel-powered light curve cannot match the combination of high peak luminosity with the fast timescale; (2) models powered by the spindown energy of a rapidly rotating magnetar predict significantly hotter and faster ejecta; and (3) models invoking shock breakout through a dense circumstellar medium cannot explain the observed spectra or color evolution. The host galaxy is well detected in pre-explosion imaging with a luminosity near L*, a star formation rate of ~15 M ☉ yr–1, and is fairly massive (~2 × 1010 M ☉), with a stellar population age of ~108 yr, also in contrast to the young dwarf hosts of known hydrogen-poor SLSNe. PS1-10afx is distinct from known examples of SLSNe in its spectra, colors, light-curve shape, and host galaxy properties, suggesting that it resulted from a different channel than other hydrogen-poor SLSNe.AstronomyPhysic