pinecone/core-2020-05-10-deduplication huggingface dataset:
Third rank Killing tensors in general relativity: The (1+1)-dimensional case

Third rank Killing tensors in (1+1)-dimensional geometries are investigated and classified. It is found that a necessary and sufficient condition for such a geometry to admit a third rank Killing tensor can always be formulated as a quadratic PDE, of order three or lower, in a Kahler type potential for the metric. This is in contrast to the case of first and second rank Killing tensors for which the integrability condition is a linear PDE. The motivation for studying higher rank Killing tensors in (1+1)-geometries, is the fact that exact solutions of the Einstein equations are often associated with a first or second rank Killing tensor symmetry in the geodesic flow formulation of the dynamics. This is in particular true for the many models of interest for which this formulation is (1+1)-dimensional, where just one additional constant of motion suffices for complete integrability. We show that new exact solutions can be found by classifying geometries admitting higher rank Killing tensors
Algebraic Solutions of the Lam\'e Equation, Revisited

A minor error in the necessary conditions for the algebraic form of the
Lam\'e equation to have a finite projective monodromy group, and hence for it
to have only algebraic solutions, is pointed out. [See F. Baldassarri, "On
algebraic solutions of Lam\'e's differential equation", J. Differential
Equations 41 (1981), 44-58.] It is shown that if the group is the octahedral
group S_4, then the degree parameter of the equation may differ by +1/6 or -1/6
from an integer; this possibility was missed. The omission affects a recent
result on the monodromy of the Weierstrass form of the Lam\'e equation. [See R.
C. Churchill, "Two-generator subgroups of SL(2,C) and the hypergeometric,
Riemann, and Lam\'e equations", J. Symbolic Computation 28 (1999), 521-545.]
The Weierstrass form, which is a differential equation on an elliptic curve,
may have, after all, an octahedral projective monodromy group.Comment: 20 pages, elsart document class, no figure
Spectrality of ordinary differential operators

We prove the long standing conjecture in the theory of two-point boundary
value problems that completeness and Dunford's spectrality imply Birkhoff
regularity. In addition we establish the even order part of S.G.Krein's
conjecture that dissipative differential operators are Birkhoff-regular and
give sharp estimate of the norms of spectral projectors in the odd case.
  Considerations are based on a new direct method, exploiting \textit{almost
orthogonality} of Birkhoff's solutions of the equation $l(y)=\lambda y$, which
was discovered earlier by the author.Comment: AmsLaTeX, 26 pages, added section on dissipative operators and
  reference
Ethnic Enclaves and the Dynamics of Social Identity on the College Campus: The Good, the Bad, and the Ugly

The effects of membership in ethnic organizations and fraternities and sororities on intergroup attitudes were examined using a 5-wave panel study at a major, multiethnic university. The results showed that these effects were similar for both minority and White students. Membership in ethnic student organizations for minorities and Greek organizations for Whites was anteceded by the degree of one's ethnic identity, and the effects of membership in these groups were similar, although not identical, for both White and minority students. These effects included an increased sense of ethnic victimization and a decreased sense of common identity and social inclusiveness. Consistent with social identity theory, at least a portion of these effects were mediated by social identity among both White and minority students.African and African American StudiesPsycholog
Charged Scalar Perturbations around Garfinkle-Horowitz-Strominger Black
  Holes

We examine the stability of the Garfinkle-Horowitz-Strominger (GHS) black
hole under charged scalar perturbations. We find that different from the
neutral scalar field perturbations, only two numerical methods, such as the
continued fraction method and the asymptotic iteration method, can keep high
efficiency and accuracy requirements in the frequency domain computations. The
comparisons of the efficiency between these two methods have also been done.
Employing the appropriate numerical method, we show that the GHS black hole is
always stable against charged scalar perturbations. This is different from the
result obtained in the de Sitter and Anti-de Sitter black holes. Furthermore we
argue that in the GHS black hole background there is no amplification of the
incident charged scalar wave to cause the superradiance, so that the
superradiant instability cannot exist in this spacetime.Comment: 24 pages, 5 figure
Measurement of very forward neutron energy spectra for 7 TeV
  proton--proton collisions at the Large Hadron Collider

The Large Hadron Collider forward (LHCf) experiment is designed to use the
LHC to verify the hadronic-interaction models used in cosmic-ray physics.
Forward baryon production is one of the crucial points to understand the
development of cosmic-ray showers. We report the neutron-energy spectra for LHC
$\sqrt{s}$ = 7 TeV proton--proton collisions with the pseudo-rapidity $\eta$
ranging from 8.81 to 8.99, from 8.99 to 9.22, and from 10.76 to infinity. The
measured energy spectra obtained from the two independent calorimeters of Arm1
and Arm2 show the same characteristic feature before unfolding the difference
in the detector responses. We unfolded the measured spectra by using the
multidimensional unfolding method based on Bayesian theory, and the unfolded
spectra were compared with current hadronic-interaction models. The QGSJET
II-03 model predicts a high neutron production rate at the highest
pseudo-rapidity range similar to our results and the DPMJET 3.04 model
describes our results well at the lower pseudo-rapidity ranges. However no
model perfectly explains the experimental results in the whole pseudo-rapidity
range. The experimental data indicate the most abundant neutron production rate
relative to the photon production, which does not agree with predictions of the
models.Comment: 10pages, 6 figure
Anomalous triple gauge couplings from $B$-meson and kaon observables

We consider the three CP-conserving dimension-6 operators that encode the
leading new-physics effects in the triple gauge couplings. The contributions to
the standard-model electromagnetic dipole and semi-leptonic vector and
axial-vector interactions that arise from the insertions of these operators are
calculated. We show that radiative and rare $B$-meson decays provide, under
certain assumptions, constraints on two out of the three anomalous couplings
that are competitive with the restrictions obtained from LEP II, Tevatron and
LHC data. The constraints arising from the $Z \to b \bar b$ electroweak pseudo
observables, $K \to \pi \nu \bar \nu$ and $\epsilon^\prime/\epsilon$ are also
studied.Comment: 17 pages, 4 figures, v2: journal version, extended comments and added
  reference
Linear polarization structures in LOFAR observations of the interstellar
  medium in the 3C196 field

This study aims to characterize linear polarization structures in LOFAR
observations of the interstellar medium (ISM) in the 3C196 field, one of the
primary fields of the LOFAR-Epoch of Reionization key science project. We have
used the high band antennas (HBA) of LOFAR to image this region and Rotation
Measure (RM) synthesis to unravel the distribution of polarized structures in
Faraday depth. The brightness temperature of the detected Galactic emission is
$5-15~{\rm K}$ in polarized intensity and covers the range from -3 to +8 ${\rm
rad~m^{-2}}$ in Faraday depth. The most interesting morphological feature is a
strikingly straight filament at a Faraday depth of $+0.5~{\rm rad~m^{-2}}$
running from north to south, right through the centre of the field and parallel
to the Galactic plane. There is also an interesting system of linear
depolarization canals conspicuous in an image showing the peaks of Faraday
spectra. We used the Westerbork Synthesis Radio Telescope (WSRT) at 350 MHz to
image the same region. For the first time, we see some common morphology in the
RM cubes made at 150 and 350~{\rm MHz}. There is no indication of diffuse
emission in total intensity in the interferometric data, in line with results
at higher frequencies and previous LOFAR observations. Based on our results, we
determined physical parameters of the ISM and proposed a simple model that may
explain the observed distribution of the intervening magneto-ionic medium. The
mean line-of-sight magnetic field component, $B_\parallel$, is determined to be
$0.3\pm0.1~{\rm \mu G}$ and its spatial variation across the 3C196 field is
$0.1~{\rm \mu G}$. The filamentary structure is probably an ionized filament in
the ISM, located somewhere within the Local Bubble. This filamentary structure
shows an excess in thermal electron density ($n_e B_\parallel>6.2~{\rm
cm^{-3}\mu G}$) compared to its surroundings.Comment: 16 pages, 10 figures, aceppted for publication in A&
Uncertainties in water chemistry in disks : an application to TW Hydrae

G.M. is supported by Ramon y Cajal grant RYC-2011-07920. I.K. acknowledges funding by an NWO MEERVOUD grant. W.F.T., P.W. and I.K. acknowledge funding from the EU FP7-2011 under Grant Agreement No. 284405. C.P. acknowledges funding from the European Commission’s 7th Framework Program (contract PERG06-GA-2009-256513) and from Agence Nationale pour la Recherche (ANR) of France under contract ANR-2010-JCJC-0504-01.Context. This paper discusses the sensitivity of water lines to chemical processes and radiative transfer for the protoplanetary disk around TW Hya. The study focuses on the Herschel spectral range in the context of new line detections with the PACS instrument from the Gas in Protoplanetary Systems project (GASPS). Aims. The paper presents an overview of the chemistry in the main water reservoirs in the disk around TW Hya. It discusses the limitations in the interpretation of observed water line fluxes. Methods. We use a previously published thermo-chemical Protoplanetary Disk Model (ProDiMo) of the disk around TW Hya and study a range of chemical modeling uncertainties: metallicity, C/O ratio, and reaction pathways and rates leading to the formation of water. We provide results for the simplified assumption of Tgas = Tdust to quantify uncertainties arising for the complex heating/cooling processes of the gas and elaborate on limitations due to water line radiative transfer. Results. We report new line detections of p-H2O (322-211) at 89.99 μm and CO J = 18-17 at 144.78 μm for the disk around TW Hya. Disk modeling shows that the far-IR fine structure lines ([O I], [C II]) and molecular submm lines are very robust to uncertainties in the chemistry, while the water line fluxes can change by factors of a few. The water lines are optically thick, sub-thermally excited and can couple to the background continuum radiation field. The low-excitation water lines are also sensitive to uncertainties in the collision rates, e. g. with neutral hydrogen. The gas temperature plays an important role for the [O I] fine structure line fluxes, the water line fluxes originating from the inner disk as well as the high excitation CO, CH+ and OH lines. Conclusions. Due to their sensitivity on chemical input data and radiative transfer, water lines have to be used cautiously for understanding details of the disk structure. Water lines covering a wide range of excitation energies provide access to the various gas phase water reservoirs (inside and outside the snow line) in protoplanetary disks and thus provide important information on where gas-phase water is potentially located. Experimental and/or theoretical collision rates for H2O with atomic hydrogen are needed to diminish uncertainties from water line radiative transfer.Publisher PDFPeer reviewe
The Virtual Tourist in Greece, 1897-1905

While travelling in Greece in 1892, a British tourist wryly commented on a group of tourists arriving in Athens who were travelling with nothing but a Baedeker guidebook and a pair of opera glasses (Armstrong, 1892). By 1892 tourist images were beginning to determine the benchmark for authentic vistas of Greece. This argument analyses an early technology for generating three dimensional images of Greece and the technological, ideological and discursive features that distinguish a particular iteration of the early tourist gaze. The study seeks to bring research from the humanities on tourism in Greece to a broader audience as a means of investigating the potential for more productive cross-flows in research covering tourism and the arts and humanities. HIGHLIGHTS: • Research in tourism to Greece in the late nineteenth and early twentieth centuries is predominantly conducted in the arts and humanities. • Tourist guidebooks to Greece in the nineteenth century shift from a focus on oriental to classical stereotypes. • Stereoscopic guides through Greece in the late nineteenth and early twentieth centuries reproduced, and contradicted, guidebook stereotypes. KEYWORDS: Greece, interdisciplinary, stereoscope, visual, guideboo
Immunopathogenic mechanisms of Coronary Artery Disease and plaque destabilization

Inflammation seems to play a role in both the chronic atherosclerotic process as well as in plaque destabilization, leading to the development of acute coronary syndromes (ACS). The aim of this study was to further investigate the immunopathogenic mechanisms in patients with coronary artery disease (CAD), primarily focusing on i) the pathogenic role of chemokines, ii) platelet-mediated inflammation, and iii) the pathogenic role of activin A as a potential “new” anti-inflammatory mediator in this process. We found that platelets upon activation released the inflammatory cytokine LIGHT, a member of the TNF superfamiliy, and that platelet-derived LIGHT could promote endothelial cell activation, potentially contributing to vascular inflammation in atherosclerotic disorders. The traditionally platelet-derived chemokine NAP-2 was also produced by peripheral mononuclear cells (PBMC), and we found that NAP-2 has the potential to induce an inflammatory response within the atherosclerotic plaque involving interaction between platelets, leukocytes and endothelial cells. By its ability to promote leukocyte activation as well as expression of chemokines and adhesion molecules within the vessel wall, such a NAP-2-driven inflammation could ultimately lead to plaque rupture and ACS. CAD patients had raised levels of the CXC chemokine CXCL16, with significantly down-regulatory effects of statins. Our in vitro experiments, showing potential inflammatory and matrix degrading properties of CXCL16, indicate that soluble CXCL16 is not only a marker, but also a mediator of inflammation with particularly enhancing effects in CAD patients. We also showed abnormal regulation of the homeostatic chemokines CCL19 and CCL21 and their common receptor CCR7 in atherosclerosis with particularly disturbed expression in unstable and advanced clinical and experimental disease. By recruiting T cells and macrophages to the atherosclerotic lesions, by promoting inflammatory responses in T cells, and by inducing a matrix degrading, pro-thrombotic, and inflammatory phenotype in macrophages, these chemokines could contribute to atherogenesis and plaque destabilization. In contrast, activin A, which was found to be up-regulated in CAD patients, was shown to display anti-inflammatory properties on mononuclear cells, in particular in patients with unstable disease. Our findings illustrate the complex regulation of the inflammatory responses during atherogenesis and plaque destabilization. Further studies on these aspects could potentially lead to new treatment modalities in these disorders
Exactly solvable D-N-type quantum spin models with long-range interaction

We derive the spectra of the D-N-type Calogero (rational) su(m) spin model, including the degeneracy factors of all energy levels. By taking the strong coupling limit of this model, in which its spin and dynamical degrees of freedom decouple, we compute the exact partition function of the su(m) Polychronakos-Frahm spin chain of D-N type. In particular, we show that this partition function cannot be obtained as a limiting case of its BCN counterpart. With the help of the partition function we study several statistical properties of the chain's spectrum, such as the density of energy levels and the distribution of spacings between consecutive levels
Temporal and spatial structure of multi‐millennial temperature changes at high latitudes during the Last Interglacial

The Last Interglacial (LIG, 129–116 thousand of years BP, ka) represents a test bed for climate model feedbacks in warmer-than-present high latitude regions. However, mainly because aligning different palaeoclimatic archives and from different parts of the world is not trivial, a spatio-temporal picture of LIG temperature changes is difficult to obtain.\ud
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Here, we have selected 47 polar ice core and sub-polar marine sediment records and developed a strategy to align them onto the recent AICC2012 ice core chronology. We provide the first compilation of high-latitude temperature changes across the LIG associated with a coherent temporal framework built between ice core and marine sediment records. Our new data synthesis highlights non-synchronous maximum temperature changes between the two hemispheres with the Southern Ocean and Antarctica records showing an early warming compared to North Atlantic records. We also observe warmer than present-day conditions that occur for a longer time period in southern high latitudes than in northern high latitudes. Finally, the amplitude of temperature changes at high northern latitudes is larger compared to high southern latitude temperature changes recorded at the onset and the demise of the LIG.\ud
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We have also compiled four data-based time slices with temperature anomalies (compared to present-day conditions) at 115 ka, 120 ka, 125 ka and 130 ka and quantitatively estimated temperature uncertainties that include relative dating errors. This provides an improved benchmark for performing more robust model-data comparison. The surface temperature simulated by two General Circulation Models (CCSM3 and HadCM3) for 130 ka and 125 ka is compared to the corresponding time slice data synthesis. This comparison shows that the models predict warmer than present conditions earlier than documented in the North Atlantic, while neither model is able to produce the reconstructed early Southern Ocean and Antarctic warming. Our results highlight the importance of producing a sequence of time slices rather than one single time slice averaging the LIG climate conditions
Application of the fast multipole method to hybrid finite element-boundary element models

This paper focuses on the acceleration of the hybrid finite element–boundary element analysis of 2D eddy current problems by means of the fast multipole method. An adaptive truncation scheme for the expansion of the 2D Laplace Green function is proposed. A linear time harmonic test case is considered. The results obtained with the hybrid model, with and without fast multipole acceleration, agree well with those obtained with a finite element model. The computational cost of the three calculations is compared and discussed. The proposed adaptive truncation scheme significantly contributes to the computation time savings achieved with the fast multipole method, particularly when dealing with moderate sized problems.status: publishe
3.5 keV X-ray line from nearly-degenerate WIMP dark matter decays

The unidentified emission line at the energy of ~3.5 keV observed in X-rays from galaxy clusters may originate from a process involving a dark matter particle. On the other hand, a weakly interacting massive particle (WIMP) has been an attractive dark matter candidate, due to its well-understood thermal production mechanism and its connection to physics at the TeV scale. In this paper, we pursue the possibility that the 3.5 keV X-ray arises from a late time decay of a WIMP dark matter into another WIMP dark matter, both of which have the mass of O (100) GeV and whose mass splitting is about 3.5 keV. We focus on the simplest case where there are two Majorana dark matter particles and two charged scalars that couple with a standard model matter particle. By assuming a hierarchical structure in the couplings of the two dark matter particles and two charged scalars, it is possible to explain the 3.5 keV line and realize the WIMP dark matter scenario at the same time. Since the effective coupling of the two different Majorana dark matter particles and one photon violates CP symmetry, the model always contains a new source of CP violation, so the model’s connection to the physics of electric dipole moments is discussed. The model’s peculiar signatures at the LHC are also studied. We show the prospect of detecting the charged scalars through a detailed collider simulation
Higgs vacuum stability from the dark matter portal

We consider classically scale-invariant extensions of the Standard Model ( CSI ESM ) which stabilise the Higgs potential and have good dark matter candidates. In this framework all mass scales, including electroweak and dark matter masses, are generated dynamically and have a common origin. We consider Abelian and non-Abelian hidden sectors portally coupled to the SM with and without a real singlet scalar. We perform a careful analysis of RG running to determine regions in the parameter space where the SM Higgs vacuum is stabilised. After combining this with the LHC Higgs constraints, in models without a singlet, none of the regained parameter space in Abelian ESMs, and only a small section in the non-Abelian ESM survives. However, in all singlet-extended models we find that the Higgs vacuum can be stabilised in all of the parameter space consistent with the LHC constraints. These models naturally contain two dark matter candidates: the real singlet and the dark gauge boson in non-Abelian models. We determine the viable range of parameters in the CSI ESM framework by computing the relic abundance, imposing direct detection constraints and combining with the LHC Higgs constraints. In addition to being instrumental in Higgs stabilisation, we find that the singlet component is required to explain the observed dark matter density
Resummation and S-duality in N = 4 SYM

We consider the problem of resumming the perturbative expansions for anomalous dimensions of low twist, non-BPS operators in four dimensional $ \mathcal{N} $ = 4 supersymmetric Yang-Mills theories. The requirement of S-duality invariance imposes considerable restrictions on any such resummation. We introduce several prescriptions that produce interpolating functions on the upper half plane that are compatible with a subgroup of the full duality group. These lead to predictions for the anomalous dimensions at all points in the fundamental domain of the complex gauge coupling, and in particular at the duality-invariant values τ = i and τ = exp( iπ /3). For low-rank gauge groups, the predictions are compatible with the bounds derived by conformal bootstrap methods for these anomalous dimensions; within numerical errors, they are in good agreement with the conjecture that said bounds are saturated at a duality-invariant point. We also find that the anomalous dimensions of the lowest twist operators lie within an extremely narrow window around a straight line as we vary the moduli of the theory over the two dimensional fundamental domain