pinecone/core-2020-05-10-deduplication huggingface dataset:
Retreat history of the East Antarctic Ice Sheet since the Last Glacial Maximum

The East Antarctic Ice Sheet (EAIS) is the largest continental ice mass on Earth, and documenting its evolution since the Last Glacial Maximum (LGM) is important for understanding its present-day and future behaviour. As part of a community effort, we review geological evidence from East Antarctica that constrains the ice sheet history throughout this period (∼30,000 years ago to present). This includes terrestrial cosmogenic nuclide dates from previously glaciated regions, 14C chronologies from glacial and post-glacial deposits onshore and on the continental shelf, and ice sheet thickness changes inferred from ice cores and continental-scale ice sheet models. We also include new 14C dates from the George V Land – Terre Adélie Coast shelf. We show that the EAIS advanced to the continental shelf margin in some parts of East Antarctica, and that the ice sheet characteristically thickened by 300–400 m near the present-day coastline at these sites. This advance was associated with the formation of low-gradient ice streams that grounded at depths of >1 km below sea level on the inner continental shelf. The Lambert/Amery system thickened by a greater amount (800 m) near its present-day grounding zone, but did not advance beyond the inner continental shelf. At other sites in coastal East Antarctica (e.g. Bunger Hills, Larsemann Hills), very little change in the ice sheet margin occurred at the LGM, perhaps because ice streams accommodated any excess ice build up, leaving adjacent, ice-free areas relatively unaffected. Evidence from nunataks indicates that the amount of ice sheet thickening diminished inland at the LGM, an observation supported by ice cores, which suggest that interior ice sheet domes were ∼100 m lower than present at this time. Ice sheet recession may have started ∼18,000 years ago in the Lambert/Amery glacial system, and by ∼14,000 years ago in Mac.Robertson Land. These early pulses of deglaciation may have been responses to abrupt sea-level rise events such as Meltwater Pulse 1a, destabilising the margins of the ice sheet. It is unlikely, however, that East Antarctica contributed more than ∼1 m of eustatic sea-level equivalent to post-glacial meltwater pulses. The majority of ice sheet recession occurred after Meltwater Pulse 1a, between ∼12,000 and ∼6000 years ago, during a period when the adjacent ocean warmed significantly. Large tracts of East Antarctica remain poorly studied, and further work is required to develop a robust understanding of the LGM ice sheet expansion, and its subsequent contraction. Further work will also allow the contribution of the EAIS to post-glacial sea-level rise, and present-day estimates of glacio-isostatic adjustment to be refined
The Peroxisomal Enzyme L-PBE Is Required to Prevent the Dietary Toxicity of Medium-Chain Fatty Acids.

Specific metabolic pathways are activated by different nutrients to adapt the organism to available resources. Although essential, these mechanisms are incompletely defined. Here, we report that medium-chain fatty acids contained in coconut oil, a major source of dietary fat, induce the liver ω-oxidation genes Cyp4a10 and Cyp4a14 to increase the production of dicarboxylic fatty acids. Furthermore, these activate all ω- and β-oxidation pathways through peroxisome proliferator activated receptor (PPAR) α and PPARγ, an activation loop normally kept under control by dicarboxylic fatty acid degradation by the peroxisomal enzyme L-PBE. Indeed, L-pbe(-/-) mice fed coconut oil overaccumulate dicarboxylic fatty acids, which activate all fatty acid oxidation pathways and lead to liver inflammation, fibrosis, and death. Thus, the correct homeostasis of dicarboxylic fatty acids is a means to regulate the efficient utilization of ingested medium-chain fatty acids, and its deregulation exemplifies the intricate relationship between impaired metabolism and inflammation
The process gg->WW as a probe into the EWSB mechanism

We present the first estimate of the gluon-gluon fusion process, gg->4f, in
the high energy domain as a probe of the electroweak symmetry breaking
mechanism (EWSB). We consider the exact matrix element at
$O(\alpha_s\alpha_{em}^2)$, and we include all irreducible background coming
from qq->4f. Purely leptonic final states, pp->llvv, are numerically
investigated. We find that this channel is extremely sensitive to the regime of
the interaction between gauge bosons. It can thus be associated to the
traditionally used vector boson scattering (VBS) to improve the analysis of the
EWSB physics.Comment: 4 pages, LaTex, 5 figure
Absence of gravitational contributions to the running Yang-Mills
  coupling

The question of a modification of the running gauge coupling of (non-)
abelian gauge theories by an incorporation of the quantum gravity contribution
has recently attracted considerable interest. In this letter we perform an
involved diagrammatical calculation in the full Einstein-Yang-Mills system both
in cut-off and dimensional regularization at one loop order. It is found that
all gravitational quadratic divergencies cancel in cut-off regularization and
are trivially absent in dimensional regularization so that there is no
alteration to asymptotic freedom at high energies. The logarithmic divergencies
give rise to an extended effective Einstein-Yang-Mills Lagrangian with a
counterterm of dimension six. In the pure Yang-Mills sector this counterterm
can be removed by a nonlinear field redefinition of the gauge potential,
reproducing a classical result of Deser, Tsao and van Nieuwenhuizen obtained in
the background field method with dimensional regularization.Comment: 4 pages, 1 figure, uses revtex and feynmf. v2: references adde
Localizing estimates of the support of solutions of some nonlinear Schrodinger equations - The stationary case

The main goal of this paper is to study the nature of the support of the solution of suitable nonlinear Schrodinger equations, mainly the compactness of the support and its spatial localization. This question touches the very foundations underlying the derivation of the Schrodinger equation, since it is well-known a solution of a linear Schrodinger equation perturbed by a regular potential never vanishes on a set of positive measure. A fact, which reflects the impossibility of locating the particle. Here we shall prove that if the perturbation involves suitable singular nonlinear terms then the support of the solution is a compact set, and so any estimate on its spatial localization implies very rich information on places not accessible by the particle. Our results are obtained by the application of certain energy methods which connect the compactness of the support with the local vanishing of a suitable "energy function" which satisfies a nonlinear differential inequality with an exponent less than one. The results improve and extend a previous short presentation by the authors published in 2006
Search for an extended VHE gamma-ray emission from Mrk 421 and Mrk 501 with the MAGIC Telescope\ud

Context. Part of the very high energy gamma-ray radiation coming from extragalactic sources is absorbed through the pair production process on the extragalactic background light photons. Extragalactic magnetic fields alter the trajectories of these cascade pairs and, in turn, convert cosmic background photons to.-ray energies by inverse Compton scattering. These secondary photons can form an extended halo around bright VHE sources. Aims. We searched for an extended emission around the bright blazars Mrk 421 and Mrk 501 using the MAGIC telescope data. Methods. If extended emission is present, the angular distribution of reconstructed gamma-ray arrival directions around the source is broader than for a point-like source. In the analysis of a few tens of hours of observational data taken from Mrk 421 and Mrk 501 we used a newly developed method that provides better angular resolution. This method is based on the usage of multidimensional decision trees. Comparing the measured shapes of angular distributions with those expected from a point-like source one can detect or constrain possible extended emission around the source. We also studied the influence of different types of systematic errors on the shape of the distribution of reconstructed gamma-ray arrival directions for a point source. Results. We present upper limits for an extended emission calculated for both sources for various source extensions and emission profiles. We obtain upper limits on the extended emission around the Mrk 421 (Mrk 501) on the level of <5% (<4%) of the Crab Nebula flux above the energy threshold of 300 GeV. Using these results we discuss possible constraints on the extragalactic magnetic fields strength around a few times 10(-15) G.\u
Search for the neutral Higgs bosons of the minimal supersymmetric standard model in pp collisions at √s = 7 TeV with the ATLAS detector

A search for neutral Higgs bosons of the Minimal Supersymmetric Standard Model (MSSM) is reported. The analysis is based on a sample of proton-proton collisions at a centre-of-mass energy of 7 TeV recorded with the ATLAS detector at the Large Hadron Collider. The data were recorded in 2011 and correspond to an integrated luminosity of 4.7 fb[superscript −1] to 4.8 fb[superscript −1]. Higgs boson decays into oppositely-charged muon or τ lepton pairs are considered for final states requiring either the presence or absence of b-jets. No statistically significant excess over the expected background is observed and exclusion limits at the 95% confidence level are derived. The exclusion limits are for the production cross-section of a generic neutral Higgs boson, ϕ, as a function of the Higgs boson mass and for h/A/H production in the MSSM as a function of the parameters m [subscript A] and tan β in the m[max over h] scenario for m [subscript A] in the range of 90 GeV to 500 GeV.United States. Dept. of EnergyNational Science Foundation (U.S.)Brookhaven National Laborator
Ionization in atmospheres of brown dwarfs and extrasolar planets. V. Alfvén ionization

Funding: European Community under the FP7 ERC starting grant. UK Science and Technology Funding Council via grant No. ST/I001808/1.Observations of continuous radio and sporadic X-ray emission from low-mass objects suggest they harbor localized plasmas in their atmospheric environments. For low-mass objects, the degree of thermal ionization is insufficient to qualify the ionized component as a plasma, posing the question: what ionization processes can efficiently produce the required plasma that is the source of the radiation? We propose Alfvén ionization as a mechanism for producing localized pockets of ionized gas in the atmosphere, having sufficient degrees of ionization (≥10) that they constitute plasmas. We outline the criteria required for Alfvén ionization and demonstrate its applicability in the atmospheres of low-mass objects such as giant gas planets, brown dwarfs, and M dwarfs with both solar and sub-solar metallicities. We find that Alfvén ionization is most efficient at mid to low atmospheric pressures where a seed plasma is easier to magnetize and the pressure gradients needed to drive the required neutral flows are the smallest. For the model atmospheres considered, our results show that degrees of ionization of 10-1 can be obtained as a result of Alfvén ionization. Observable consequences include continuum bremsstrahlung emission, superimposed with spectral lines from the plasma ion species (e.g., He, Mg, H, or CO lines). Forbidden lines are also expected from the metastable population. The presence of an atmospheric plasma opens the door to a multitude of plasma and chemical processes not yet considered in current atmospheric models. The occurrence of Alfvén ionization may also be applicable to other astrophysical environments such as protoplanetary disks.Publisher PDFPeer reviewe
Deeply Virtual Compton Scattering and its Beam Charge Asymmetry in e^\pm
  p Collisions at HERA

A measurement of elastic deeply virtual Compton scattering gamma* p -> gamma
p using e^+ p and e^- p collision data recorded with the H1 detector at HERA is
presented. The analysed data sample corresponds to an integrated luminosity of
306 pb^-1, almost equally shared between both beam charges. The cross section
is measured as a function of the virtuality Q^2 of the exchanged photon and the
centre-of-mass energy W of the gamma* p system in the kinematic domain 6.5 <
Q^2 < 80 GeV^2, 30 < W < 140 GeV and |t| < 1 GeV^2, where t denotes the squared
momentum transfer at the proton vertex. The cross section is determined
differentially in t for different Q^2 and W values and exponential t-slope
parameters are derived. Using e^+ p and e^- p data samples, a beam charge
asymmetry is extracted for the first time in the low Bjorken x kinematic
domain. The observed asymmetry is attributed to the interference between
Bethe-Heitler and deeply virtual Compton scattering processes. Experimental
results are discussed in the context of two different models, one based on
generalised parton distributions and one based on the dipole approach.Comment: Revised version, accepted by journal, 21 pages, 6 figures, 4 table
Thermodynamic Bethe Ansatz Equations for Minimal Surfaces in AdS_3

We study classical open string solutions with a null polygonal boundary in
AdS_3 in relation to gluon scattering amplitudes in N=4 super Yang-Mills at
strong coupling. We derive in full detail the set of integral equations
governing the decagonal and the dodecagonal solutions and identify them with
the thermodynamic Bethe ansatz equations of the homogeneous sine-Gordon models.
By evaluating the free energy in the conformal limit we compute the central
charges, from which we observe general correspondence between the polygonal
solutions in AdS_n and generalized parafermions.Comment: 25 pages, 4 figures, v2: a figure and references added, minor
  corrections, v3: references added, minor corrections, to appear in JHE
Two-step flux penetration in layered antiferromagnetic superconductor

A layered antiferromagnetic superconductor in the mixed state may posses
magnetic domains created along the Josephson vortices. This may happen when an
external magnetic field is strong enough to flip over magnetic moments, lying
in the phase core of the Josephson vortex, from their ground state
configuration. The formation of the domain structure of the vortices modifies
the surface energy barrier of the superconductor. During this process the
entrance of the flux is stopped and a newly created state exhibits perfect
shielding. Such behavior should be visible as a plateau on the dependence of
flux density as a function of the external magnetic field. The end of the
plateau determines the critical field, which we call the second critical field
for flux penetration.Comment: 8 pages, 3 figure
Radiation of a circulating quark in strongly coupled N=4 super
  Yang-Mills theory

The energy density and angular distribution of power radiated by a quark
undergoing circular motion in strongly coupled ${\cal N}=4$ supersymmetric
Yang-Mills (SYM) theory is computed using gauge/gravity duality. The results
are qualitatively similar to that of synchrotron radiation produced by an
electron in circular motion in classical electrodynamics: At large velocities
the quark emits radiation in a narrow beam along its velocity vector with a
characteristic opening angle $\alpha \sim 1/\gamma$ and radial thickness
scaling like $\sim 1/\gamma^3$.Comment: 8 pages, 2 figures - Talk presented by D. Nickel at QCD@Work, June
  20-23rd, 2010, Martina Franca, Ital
Quasiparticle Calculations for Point Defects on Semiconductor Surfaces

We discuss the implementation of quasiparticle calculations for point defects
on semiconductor surfaces and, as a specific example, present an ab initio
study of the electronic structure of the As vacancy in the +1 charge state on
the GaAs(110) surface. The structural properties are calculated with the
plane-wave pseudopotential method, and the quasiparticle energies are obtained
from Hedin's GW approximation. Our calculations show that the 1a" vacancy state
in the band gap is shifted from 0.06 to 0.65 eV above the valence-band maximum
after the self-energy correction to the Kohn-Sham eigenvalues. The GW result is
in close agreement with a recent surface photovoltage imaging measurement.Comment: 9 pages including 3 figures, LaTe
Black holes: A physical route to the Kerr metric

As a consequence of Birkhoff's theorem, the exterior gravitational field of a
spherically symmetric star or black hole is always given by the Schwarzschild
metric. In contrast, the exterior gravitational field of a rotating
(axisymmetric) star differs, in general, from the Kerr metric, which describes
a stationary, rotating black hole.
  In this paper, I discuss the possibility of a quasi-stationary transition
from rotating equilibrium configurations of normal matter to rotating black
holes.Comment: 14 pages, 1 table, 4 figures, accepted for publication in Annalen der
  Physik (Leipzig
A lattice field theoretical model for high-$T_c$ superconductivity

We present a 2+1-dimensional lattice model for the copper oxide
superconductors and their parent compounds, in which both the charge and spin
degrees of freedom are treated dynamically. The spin-charge coupling parameter
is associated to the doping fraction in the cuprates. The model is able to
account for the various phases of the cuprates and their properties, not only
at low and intermediate doping but also for (highly) over-doped compounds. We
acquire a qualitative understanding of high-$T_c$ superconductivity as a
Bose-Einstein condensation of bound charge pairs.Comment: talk presented in the Lattice 97 conferenc
Evolution of the N=28 shell closure: a test bench for nuclear forces

The evolution of the N=28 shell closure is investigated far from stability.
Using the latest results obtained from various experimental techniques, we
discuss the main properties of the N=28 isotones, as well as those of the N=27
and N=29 isotones. Experimental results are confronted to various theoretical
predictions. These studies pinpoint the effects of several terms of the
nucleon-nucleon interaction, such as the central, the spin-orbit, the tensor
and the three-body force components, to account for the modification of the
N=28 shell gap and spin-orbit splittings. Analogies between the evolution of
the N=28 shell closure and other magic numbers originating from the spin-orbit
interaction are proposed (N=14,50, 82 and 90). More generally, questions
related to the evolution of nuclear forces towards the drip-line, in bubble
nuclei, and for nuclei involved in the r-process nucleosynthesis are proposed
and discussed.Comment: 40 pages,15 figures, Procceedings Nobel Symposium 2012, accepted for
  publication in Physica Script
Pion-photon Transition Distribution Amplitudes in the Spectral Quark
  Model

The vector and axial pion-photon transition distribution amplitudes are
analyzed in the Spectral Quark Model. We proceed by the evaluation of double
distributions through the use of a manifestly covariant calculation based on
the alpha representation of propagators. As a result polynomiality is
incorporated and calculations become rather simple. Explicit formulas, holding
at the low-energy quark-model scale, are obtained. The corresponding form
factors for the anomalous decay pi0 -> gamma gamma* and the radiative pion
decays are also evaluated and confronted with the data.Comment: 13 pages, 3 figure
A new look at instantons and large-N limit

We analyze instantons in the very strongly coupled large-$N$ limit
($N\to\infty$ with $g^2$ fixed) of large-$N$ gauge theories, where the effect
of the instantons remains finite. By using the exact partition function of
four-dimensional ${\cal N}=2^*$ gauge theories as a concrete example, we
demonstrate that each instanton sector in the very strongly coupled large-$N$
limit is related to the one in the 't Hooft limit ($N\to\infty$ with $g^2N$
fixed) through a simple analytic continuation. Furthermore we show the
equivalence between the instanton partition functions of a pair of large-$N$
gauge theories related by an orbifold projection. This can open up a new way to
analyze the partition functions of low/non-supersymmetric theories. We also
discuss implication of our result to gauge/gravity dualities for M-theory as
well as a possible application to large-$N$ QCD.Comment: 10 page
Domain Adaptation of Majority Votes via Perturbed Variation-based Label
  Transfer

We tackle the PAC-Bayesian Domain Adaptation (DA) problem. This arrives when
one desires to learn, from a source distribution, a good weighted majority vote
(over a set of classifiers) on a different target distribution. In this
context, the disagreement between classifiers is known crucial to control. In
non-DA supervised setting, a theoretical bound - the C-bound - involves this
disagreement and leads to a majority vote learning algorithm: MinCq. In this
work, we extend MinCq to DA by taking advantage of an elegant divergence
between distribution called the Perturbed Varation (PV). Firstly, justified by
a new formulation of the C-bound, we provide to MinCq a target sample labeled
thanks to a PV-based self-labeling focused on regions where the source and
target marginal distributions are closer. Secondly, we propose an original
process for tuning the hyperparameters. Our framework shows very promising
results on a toy problem
Global and local properties of AdS(2) higher spin gravity

Two-dimensional BF theory with infinitely many higher spin fields is
proposed. It is interpreted as the AdS(2) higher spin gravity model describing
a consistent interaction between local fields in AdS(2) space including
gravitational field, higher spin partially-massless fields, and dilaton fields.
We carry out analysis of the frame-like and the metric-like formulation of the
theory. Infinite-dimensional higher spin global algebras and their
finite-dimensional truncations are realized in terms of o(2,1) - sp(2) Howe
dual auxiliary variables.Comment: 51 pages; v2: comments and refs added, typos removed, JHEP versio
Exact solution of the spin-s Heisenberg chain with generic non-diagonal
  boundaries

The off-diagonal Bethe ansatz method is generalized to the high spin
integrable systems associated with the su(2) algebra by employing the spin-s
isotropic Heisenberg chain model with generic integrable boundaries as an
example. With the fusion techniques, certain closed operator identities for
constructing the functional T-Q relations and the Bethe ansatz equations are
derived. It is found that a variety of inhomogeneous T-Q relations obeying the
operator product identities can be constructed. Numerical results for two-site
s=1 case indicate that an arbitrary choice of the derived T-Q relations is
enough to give the complete spectrum of the transfer matrix.Comment: 26 pages, 2 tables, 1 figure, published versio
On the Validity of the Geiger-Nuttall Alpha-Decay Law and its
  Microscopic Basis

The Geiger-Nuttall (GN) law relates the partial $\alpha$-decay half-life with
the energy of the escaping $\alpha$ particle and contains for every isotopic
chain two experimentally determined coefficients. The expression is supported
by several phenomenological approaches, however its coefficients lack a fully
microscopic basis. In this paper we will show that: 1) the empirical
coefficients that appear in the GN law have a deep physical meaning and 2) the
GN law is successful within the restricted experimental data sets available so
far, but is not valid in general. We will show that, when the dependence of
logarithm values of the $\alpha$ formation probability on the neutron number is
not linear or constant, the GN law is broken. For the $\alpha$ decay of
neutron-deficient nucleus $^{186}$Po, the difference between the experimental
half-life and that predicted by the GN Law is as large as one order of
magnitude.Comment: 4 pages, 5 figures, to appear in Phys. Lett.