pinecone/core-2020-05-10-deduplication huggingface dataset:
Roles of resonance and dark irradiance for infrared photorefractive
  self-focusing and solitons in bi-polar InP:Fe

This paper shows experimental evidence of photorefractive steady state
self-focusing in InP:Fe for a wide range of intensities, at both 1.06 and
1.55$\mu$m. To explain those results, it is shown that despite the bi-polar
nature of InP:Fe where one photocarrier and one thermal carrier are to be
considered, the long standing one photocarrier model for photorefractive
solitons can be usefully applied. The relationship between the dark irradiance
stemming out of this model and the known resonance intensity is then discussed
Optical Lattices with Micromechanical Mirrors

We investigate a setup where a cloud of atoms is trapped in an optical
lattice potential of a standing wave laser field which is created by
retro-reflection on a micro-membrane. The membrane vibrations itself realize a
quantum mechanical degree of freedom. We show that the center of mass mode of
atoms can be coupled to the vibrational mode of the membrane in free space, and
predict a significant sympathetic cooling effect of the membrane when atoms are
laser cooled. The controllability of the dissipation rate of the atomic motion
gives a considerable advantage over typical optomechanical systems enclosed in
optical cavities, in that it allows a segregation between the cooling and
coherent dynamics regimes. The membrane can thereby be kept in a cryogenic
environment, and the atoms at a distance in a vacuum chamber
On the high-density expansion for Euclidean Random Matrices

Diagrammatic techniques to compute perturbatively the spectral properties of
Euclidean Random Matrices in the high-density regime are introduced and
discussed in detail. Such techniques are developed in two alternative and very
different formulations of the mathematical problem and are shown to give
identical results up to second order in the perturbative expansion. One method,
based on writing the so-called resolvent function as a Taylor series, allows to
group the diagrams in a small number of topological classes, providing a simple
way to determine the infrared (small momenta) behavior of the theory up to
third order, which is of interest for the comparison with experiments. The
other method, which reformulates the problem as a field theory, can instead be
used to study the infrared behaviour at any perturbative order.Comment: 29 page
Flavor-Symmetry Restoration and Symanzik Improvement for Staggered Quarks

We resolve contradictions in the literature concerning the origins and size of unphysical flavor-changing strong interactions generated by the staggered-quark discretization of QCD. We show that the leading contributions are tree-level in $\order(a^2)$ and that they can be removed by adding three correction terms to the link operator in the standard action. These corrections are part of the systematic Symanzik improvement of the staggered-quark action. We present a new improved action for staggered quarks that is accurate up to errors of $\order(a^4,a^2\alpha_s)$ --- more accurate than most, if not all, other discretizations of light-quark dynamics
Discrete Black-Hole Radiation and the Information Loss Paradox

Hawking's black hole information puzzle highlights the incompatibility between our present understanding of gravity and quantum physics. However, Hawking's prediction of black-hole evaporation is at a semiclassical level. One therefore suspects some modifications of the character of the radiation when quantum properties of the {\it black hole itself} are properly taken into account. In fact, during the last three decades evidence has been mounting that, in a quantum theory of gravity black holes may have a discrete mass spectrum, with concomitant {\it discrete} line emission. A direct consequence of this intriguing prediction is that, compared with blackbody radiation, black-hole radiance is {\it less} entropic, and may therefore carry a significant amount of {\it information}. Using standard ideas from quantum information theory, we calculate the rate at which information can be recovered from the black-hole spectral lines. We conclude that the information that was suspected to be lost may gradually leak back, encoded into the black-hole spectral lines
Picture-Changing operators and Space-Time supersymmetry

We explore geometrical properties of fermionic vertex operators for a NSR
superstring in order to establish connection between worldsheet and target
space supersymmetries. The mechanism of picture-changing is obtained as a
result of imposing certain constraints on a world-sheet gauge group of the NSR
theory. It is found that picture-changing operators of various integer ghost
numbers form a polynomial ring. By using properties of the picture-changing
formalism we establish connection between the NSR and GS superstring theories.
We explore the properties of the $\kappa$-symmetry in the NSR formalism and
show that it leads to some new identities between correlation functions.Comment: 24 page
Nonlinear stability of oscillatory wave fronts in chains of coupled
  oscillators

We present a stability theory for kink propagation in chains of coupled
oscillators and a new algorithm for the numerical study of kink dynamics. The
numerical solutions are computed using an equivalent integral equation instead
of a system of differential equations. This avoids uncertainty about the impact
of artificial boundary conditions and discretization in time. Stability results
also follow from the integral version. Stable kinks have a monotone leading
edge and move with a velocity larger than a critical value which depends on the
damping strength.Comment: 11 figure
Clustering in Complex Directed Networks

Many empirical networks display an inherent tendency to cluster, i.e. to form
circles of connected nodes. This feature is typically measured by the
clustering coefficient (CC). The CC, originally introduced for binary,
undirected graphs, has been recently generalized to weighted, undirected
networks. Here we extend the CC to the case of (binary and weighted) directed
networks and we compute its expected value for random graphs. We distinguish
between CCs that count all directed triangles in the graph (independently of
the direction of their edges) and CCs that only consider particular types of
directed triangles (e.g., cycles). The main concepts are illustrated by
employing empirical data on world-trade flows
Knowledge, attitudes and practices of medical staff towards obesity management in patients with spinal cord injuries: an International survey of four western European countries

Objective: To (1) examine the opinions of medical staff working in spinal cord injury (SCI) centres (SCICs); (2) evaluate their knowledge, attitudes and practices towards obesity prevention and management; (3) report the number of beds and dietitians available at each SCIC. Methods: A 37-item questionnaire was sent to 23 SCICs in the UK, the Netherlands, Belgium and the Republic of Ireland between September 2012 and January 2013. Results: Eighteen SCICs returned the questionnaires for analysis. All respondents stated that they had an interest in obesity treatment but only 2.3% of the respondents received training in obesity management. Sixty-one percent of staff did not consider body mass index (BMI) to be appropriate for use in SCI patients and subsequently less than half of the respondents use BMI routinely. The majority of respondents reported that they are confident in dealing with overweight (74.5%) and obese (66.1%) SCI adults, less than half (44.1%) are confident in treating overweight and obese SCI children. Respondents also indicated the need for nationally adopted guidelines and a lack of physical activity provision. There were 17.5 whole-time equivalent (WTE) dietitians recorded in 22 SCICs, equivalent to 47.8 beds per WTE dietitians (range 10–420). Non-UK SCIC dietitians are significantly better resourced than in UK SCICs (beds per WTE dietitian: 36 vs 124, P=0.035). Conclusion: Medical staff expressed the need to participate in obesity prevention and management. Appropriate training should be considered for all medical staff and the development of specific weight management guidelines and dietetic provision should be considered
Molecular and macromolecular structure changes in polyamide 11 during thermal oxidation

The present article reports a study of thermal oxidation of unstabilized polyamide 11 films at several temperatures (90–165 °C) under atmospheric pressure and under various oxygen pressures (up to 1.6 MPa) at 110 °C. The chemical structure changes are monitored by IR spectroscopy (carbonyl groups) and UV–visible spectrophotometry (yellowing). Molar mass changes are determined by size exclusion chromatography (SEC). By investigating the influence of oxygen pressure it is clearly shown that reactions involving P° radicals other than O2 addition cannot be neglected under atmospheric pressure. Under the conditions of this study limited to relatively low oxidation levels, IR and UV measurements indicate that carbonyl groups and chromophores responsible for yellowing have the same relative yield whatever the temperature and oxygen pressure. SEC measurements highlight the significant predominance of random chain scissions over crosslinking events. Crosslinking only appears after an induction time, presumably because it involves reactions between primary oxidation products. The ratio of carbonyl groups over chain scissions is about 7.5 at low conversion and about 2.5 at high conversion, showing that α amino alkoxy radicals are mainly transformed into imides without chain scission
Cosmology in bimetric theory with an effective composite coupling to
  matter

We study the cosmology of bimetric theory with a composite matter coupling.
We find two possible branches of background evolution. We investigate the
question of stability of cosmological perturbations. For the tensor and vector
perturbations, we derive conditions on the absence of ghost and gradient
instabilities. For the scalar modes, we obtain conditions for avoiding ghost
degrees. In the first branch, we find that one of the scalar modes becomes a
ghost at the late stages of the evolution. Conversely, this problem can be
avoided in the second branch. However, we also find that the constraint for the
second branch prevents the doubly coupled matter fields from being the standard
ingredients of cosmology. We thus conclude that a realistic and stable
cosmological model requires additional minimally coupled matter fields.Comment: 22 page
Opinion dynamics: inhomogeneous Boltzmann-type equations modelling opinion leadership and political segregation

We propose and investigate different kinetic models for opinion formation, when the opinion formation process depends on an additional independent variable, e.g. a leadership or a spatial variable. More specifically, we consider: (i) opinion dynamics under the effect of opinion leadership, where each individual is characterised not only by its opinion, but also by another independent variable which quantifies leadership qualities; (ii) opinion dynamics modelling political segregation in the `The Big Sort', a phenomenon that US citizens increasingly prefer to live in neighbourhoods with politically like-minded individuals. Based on microscopic opinion consensus dynamics such models lead to inhomogeneous Boltzmann-type equations for the opinion distribution. We derive macroscopic Fokker-Planck-type equations in a quasi-invariant opinion limit and present results of numerical experiments
Learning outcomes across disciplines and professions: Measurement and interpretation

Learning outcomes of higher education are a quality tool in a changing higher education landscape but cannot be seen as neutral measures across professions and disciplines. Survey results from graduates and recent graduates indicate that prevailing measures of learning outcomes yield the same result within and across disciplinary and professional divides. The main interpretation is that learning outcomes must be seen as a valid construct but that the results are highly dependent on the profession and discipline in a way that cannot be reduced to differences in learning outcomes only; measurements of learning outcomes must also be interpreted as mirroring different knowledge structures and knowledge bases in different professions and disciplines. Thus, attempts to make neutral comparisons of learning outcomes between different professions and disciplines are vulnerable to measuring only the differences in knowledge structures
Safety climate dimensions as predictors for risk behavior

This study examines the interactive relationship between three dimensions of safety climate (management commitment to safety, priority of safety, and pressure for production), and their impact on risk behavior reported by employees. The sample consisted of 623 employees from a chemical manufacturing organization in South Africa. Hierarchical regression analyses were carried out to test the direct effects and the interaction effect of the three safety climate dimensions on risk behavior. The results showed that, as expected, employees’ risk behavior was negatively related to management commitment to safety and priority of safety and positively related to pressure for production. Moreover, as expected, the three-way interaction between management commitment to safety, priority of safety and pressure for production was significant. When pressure for production was high, management commitment to safety was positively related to risk behavior, regardless of level of priority of safety on plant. When pressure for production was low, the effect of management commitment to safety on risk behavior was nullified under conditions of high, as compared to low priority of safety on plant. These findings highlight the importance of managerial commitment to safety in contexts where employees experience tensions between production deadlines and safety procedures
Does relatedness influence migratory timing and behaviour in Atlantic salmon smolts?

Aggregating and moving with relatives may enable animals to increase opportunities for kin selection to occur. To gain group-living benefits, animals must coordinate their behaviour. Atlantic salmon, Salmo salar, demonstrate both territoriality and schooling: the two key social behaviours performed by fish. In this investigation we compared the migratory timing and behaviour of six distinct full-sibling groups of tagged S. salar smolts with a large control sample from the same wild population. The results clearly demonstrate that the incidence of schooling and diel migratory timing is not significantly influenced by relatedness, and this adds further support to the hypothesis that S. salar smolt migration is primarily an adaptive response to environmental conditions, rather than a behaviour based solely on genetics or kin-biased behaviour. Used in conjunction with the results of two previous investigations, this is the first study to illustrate that kin discrimination among full-sibling groups of parr does not lead to kin-biased schooling in smolts. Thus, even within the same full-sibling groups, the extent of kin-biased behaviour in fish can both differ within a life history stage under varying ecological conditions and shift from one life history stage to the next
Constrained inflaton due to a complex scalar

We reexamine inflation due to a constrained inflaton in the model of a complex scalar. Inflaton evolves along  a spiral-like valley of special scalar potential in the scalar  field space just like single field inflation.  Sub-Planckian inflaton can induce sufficient e-foldings because of a long slow-roll path. In a special limit,  the scalar spectral index and the tensor-to-scalar ratio has  equivalent expressions to the inflation with monomial potential  φn. The favorable values for them could be obtained  by varying parameters in the potential.  This model could be embedded in a certain radiative neutrino  mass mode
Universal turbulence on branes in holography

At a meson melting transition in holographic QCD, a weak turbulence of mesons was found with critical embeddings of probe D-branes in gravity duals. The turbulent mesons have a power-law energy distribution ε n ∝ ( ω n ) α where ω n is the mass of the n -th excited resonance of the meson tower. In this paper, we find that the turbulence power α is universal, irrespective of how the transition is driven, by numerically calculating the power in various static brane setups at criticality. We also find that the power α depends only on the cone dimensions of the probe D-branes
Evidence for the suppression of intermediate anti-ferroelectric ordering and observation of hardening mechanism in Na1/2Bi 1/2TiO3 ceramics through cobalt substitution

Co-ion (5 mol %) substitution in Na1/2Bi1/2TiO 3 (NBT) host lattice and their effects on the structural, ferroelectric and dielectric behavior has been investigated thoroughly in this present study. The substituted Co-ion at Ti-site acts an acceptor type doping and hardens (i.e., increase in coercivity) the system without any noticeable change in the remanent polarization values. However, the intermediate antiferroelectric (AFE) ordering which exists between 200 C-280 C in NBT system has been suppressed due to Co-ion substitution, which is an interesting feature for device applications
Phase structure and the gluon propagator of SU(2) gauge-Higgs model in two dimensions

We study numerically the phase structure and the gluon propagator of the SU(2) gauge-Higgs model in two dimensions. First, we calculate gauge-invariant quantities, in particular the static potential from Wilson Loop, the W propagator, and the plaquette expectation value. Our results suggest that a confinement-like region and a Higgs-like region appear even in two dimensions. In the confinement-like region, the static potential rises linearly, with string breaking at large distances, while in the Higgs-like region, it is of Yukawa type, consistent with a Higgs-type mechanism. The correlation length obtained from the W propagator has a finite maximum between these regions. The plaquette expectation value shows a smooth cross-over consistent with the Fradkin-Shenker-Osterwalder-Seiler theorem. From these results, we suggest that there is no phase transition in two dimensions. We also calculate a gauge-dependent order parameter in Landau gauge. Unlike gauge invariant quantities, the gauge non-invariant order parameter has a line of discontinuity separating these two regions. Finally we calculate the gluon propagtor. We infer from its infrared behavior that the gluon propagator would vanish at zero momentum in the infinite-volume limit, consistent with an analytical study
An evaluation of the PM2.5 trace elemental composition in the VeniceLagoon area and an analysis of the possible sources

Global emissions reported by many authors have shown as natural and anthropic sources can contribute\ud
to the principal aerosol classes, but values change according the local scenario. The Venice Lagoon is\ud
exposed to different anthropic source emissions like vehicular traffic, industrial thermoelectric power\ud
plant, petrochemical plant, incinerator plant, domestic heating, ship traffic, glass factories and airport.\ud
Samplings of PM2.5 were daily performed between March and November 2007 in Sacca San Biagio island\ud
(Venice), and values of PM2.5 concentration and element concentration were obtained. Monthly average\ud
concentrations (mgm3) during this period show higher values during the spring and the autumn. A good\ud
relationship between data obtained and concentration values from environmental local agencies is\ud
evidenced, both for PM2.5 from urban area (Venezia Mestre), and for PM10 sampled in the same area, as\ud
well as the influence of some meteorological parameters on PM2.5 concentration sampled. Trace\ud
elements samples were measured by an Inductively Coupled Plasma-Quadrupole Mass Spectrometry\ud
(ICP-QMS), and values (ng m3 and mg g1) for elements regulated by European directives (As, Cd, Ni, Pb),\ud
as well as, other elements (Na, Al, K, Ti, V, Mn, Fe, Co, Zn, Se, Ag) are also reported. Data analysis by mean\ud
of Principal Component Analysis (PCA) and Positive Matrix Factorization (PMF) pointed out four principal\ud
groups of elements like Mn–Fe–K, As–Se–Cd, V–Co, and Pb that could be assigned to specific sources of\ud
the Venetian wetland basin
Financial contagion in the laboratory: The cross-market rebalancing channel

We present the results of the first experimental study of financial markets contagion. We develop a model of financial contagion amenable to be tested in the laboratory. In the model, contagion happens because of cross-market rebalancing, a channel for transmission of shocks across markets first studied by Kodres and Pritsker (2002). Theory predicts that, because of portfolio rebalancing, a negative shock in one market transmits itself to the others, as investors adjust their portfolio allocations. The theory is supported by the experimental results. The price observed in the laboratory is close to that predicted by theory, and strong contagion effects are observed. The results are robust across different market structures. Moreover, as theory predicts, lower asymmetric information in a (“developed”) financial market increases the contagion effects in (“emerging”) markets
Isotropy Properties of the Multi-Step Markov Symbolic Sequences

A new object of the probability theory, the two-sided chain of symbols (introduced in Ref. arXiv:physics/0306170) is used to study isotropy properties of binary multi-step Markov chains with the long-range correlations. Established statistical correspondence between the Markov chains and certain two-sided sequences allows us to prove the isotropy properties of three classes of the Markov chains. One of them is the important class of weakly correlated additive Markov chains, which turned out to be equivalent to the additive two-sided sequences
The quantum fidelity for the time-dependent singular quantum oscillator

Journal of Mathematical Physics ThéorieIn this paper we perform an exact study of ``Quantum Fidelity'' (also called Loschmidt Echo) for the time-periodic quantum Harmonic Oscillator of Hamiltonian : $$ \hat H_{g}(t):=\frac{P^2}{2 }+ f(t)\frac{Q^2}{2}+\frac{g^2}{Q^2} $$ when compared with the quantum evolution induced by $\hat H_{0}(t)$ ($g=0$), in the case where $f$ is a $T$-periodic function and $g$ a real constant. The reference (initial) state is taken to be an arbitrary ``generalized coherent state'' in the sense of Perelomov. We show that, starting with a quadratic decrease in time in the neighborhood of $t=0$, this quantum fidelity may recur to its initial value 1 at an infinite sequence of times {$t_{k}$}. We discuss the result when the classical motion induced by Hamiltonian $\hat H_{0}(t)$ is assumed to be stable versus unstable. A beautiful relationship between the quantum and the classical fidelity is also demonstrated