pinecone/core-2020-05-10-deduplication huggingface dataset:
Gauge field emergence from Kalb–Ramond localization

AbstractA new mechanism, valid for any smooth version of the Randall–Sundrum model, of getting localized massless vector field on the brane is described here. This is obtained by dimensional reduction of a five dimension massive two form, or Kalb–Ramond field, giving a Kalb–Ramond and an emergent vector field in four dimensions. A geometrical coupling with the Ricci scalar is proposed and the coupling constant is fixed such that the components of the fields are localized. The solution is obtained by decomposing the fields in transversal and longitudinal parts and showing that this gives decoupled equations of motion for the transverse vector and KR fields in four dimensions. We also prove some identities satisfied by the transverse components of the fields. With this is possible to fix the coupling constant in a way that a localized zero mode for both components on the brane is obtained. Then, all the above results are generalized to the massive p-form field. It is also shown that in general an effective p and (p−1)-forms cannot be localized on the brane and we have to sort one of them to localize. Therefore, we cannot have a vector and a scalar field localized by dimensional reduction of the five dimensional vector field. In fact we find the expression p=(d−1)/2 which determines what forms will give rise to both fields localized. For D=5, as expected, this is valid only for the KR field
A fast vector penalty-projection method for incompressible non-homogeneous or multiphase Navier–Stokes problems

AbstractWe present a new fast vector penalty-projection method (V PPε) to efficiently compute the solution of unsteady Navier–Stokes problems governing incompressible multiphase viscous flows with variable density and/or viscosity. The key idea of the method is to compute at each time step an accurate and curl-free approximation of the pressure gradient increment in time. This method performs a two-step approximate divergence-free vector projection yielding a velocity divergence vanishing as O(εδt), δt being the time step, with a penalty parameter ε as small as desired until the machine precision, e.g. ε=10−14, whereas the solution algorithm can be extremely fast and cheap. Indeed, the proposed vector correction step typically requires only a few iterations of a suitable preconditioned Krylov solver whatever the spatial mesh step. The method is numerically validated on three benchmark problems for non-homogeneous or multiphase flows where we compare it to the Uzawa augmented Lagrangian (UAL) and scalar incremental projection (SIP) methods. Moreover, a new test case for fluid–structure interaction problems is also investigated. That results in a very robust method running faster than usual methods and being able to efficiently and accurately compute sharp test cases whatever the density, viscosity or anisotropic permeability jumps, whereas other methods crash
The role of aluminium in chemical and phase segregation in a TRIP-assisted dual phase steel

AbstractIn this work we demonstrate that micro-segregation patterns of alloying elements present in a high-strength TRIP-assisted DP steel after casting are retained in the microstructure throughout processing, and lead to anisotropy (banding) in the final microstructure. In particular, we have assessed the role of Al on the chemical segregation of Mn, Cr and Si during casting, and their impact on the phase transformations occurring during thermo-mechanical processing of the as-cast material. We have derived the elemental partition coefficients, based on the experimentally determined dendrite spacing and chemical profiles in the as-cast structure, and used them to derive the local austenite-to-ferrite transformation temperature. Our cellular automaton methodology to simulate phase transformations allows reliable prediction of the formation or suppression of banding in the intermediate and final microstructures for different heating or cooling rates. Our results reveal that aluminium exerts the largest individual effect of the substitutional elements on the formation of banding in these steels. Controlling micro-segregation during solidification in advanced high-strength multiphase steels is therefore critical for obtaining homogeneous mechanical properties in the final product, as it controls the phase transformations occurring during thermo-mechanical processing and therefore the final microstructure
Quantitative computed tomography–derived clusters: Redefining airway remodeling in asthmatic patients

BackgroundAsthma heterogeneity is multidimensional and requires additional tools to unravel its complexity. Computed tomography (CT)–assessed proximal airway remodeling and air trapping in asthmatic patients might provide new insights into underlying disease mechanisms.ObjectivesThe aim of this study was to explore novel, quantitative, CT-determined asthma phenotypes.MethodsSixty-five asthmatic patients and 30 healthy subjects underwent detailed clinical, physiologic characterization and quantitative CT analysis. Factor and cluster analysis techniques were used to determine 3 novel, quantitative, CT-based asthma phenotypes.ResultsPatients with severe and mild-to-moderate asthma demonstrated smaller mean right upper lobe apical segmental bronchus (RB1) lumen volume (LV) in comparison with healthy control subjects (272.3 mm3 [SD, 112.6 mm3], 259.0 mm3 [SD, 53.3 mm3], 366.4 mm3 [SD, 195.3 mm3], respectively; P = .007) but no difference in RB1 wall volume (WV). Air trapping measured based on mean lung density expiratory/inspiratory ratio was greater in patients with severe and mild-to-moderate asthma compared with that seen in healthy control subjects (0.861 [SD, 0.05)], 0.866 [SD, 0.07], and 0.830 [SD, 0.06], respectively; P = .04). The fractal dimension of the segmented airway tree was less in asthmatic patients compared with that seen in control subjects (P = .007). Three novel, quantitative, CT-based asthma clusters were identified, all of which demonstrated air trapping. Cluster 1 demonstrates increased RB1 WV and RB1 LV but decreased RB1 percentage WV. On the contrary, cluster 3 subjects have the smallest RB1 WV and LV values but the highest RB1 percentage WV values. There is a lack of proximal airway remodeling in cluster 2 subjects.ConclusionsQuantitative CT analysis provides a new perspective in asthma phenotyping, which might prove useful in patient selection for novel therapies
High-precision ϵ-expansions of three-loop master integrals contributing to the electron g–2 in QED

AbstractIn this Letter we calculate at high-precision the Laurent expansions in ϵ=(4−D)/2 of the 17 master integrals which appeared in the analytical calculation of 3-loop QED contribution to the electron g–2, using difference and differential equations. The coefficients of the expansions so obtained are in perfect agreement with all the analytical expressions already known. The values of coefficients not previously known will be used in the high-precision calculation of the 4-loop QED contribution to the electron g–2
New aminocyclitols with quaternary stereocentres via acylnitroso cycloaddition with an ipso,ortho arene dihydrodiol

AbstractMicrobial ipso,ortho-dihydroxylation of benzoic acid by the B9 mutant strain of Ralstonia eutropha permits rapid construction of aminocyclitols containing a quaternary stereocentre. Installation of the amine functionality is achieved by use of an acylnitroso dienophile for a hetero-Diels–Alder reaction. Both aminotetrols and aminohexols are accessible as single enantiomers by this route. Both NOESY spectroscopic and X-ray crystallographic analyses were required to distinguish cycloadduct isomers. Notably, subsequent to the biooxidation step, all new stereocentres are installed under substrate control. Thus, all stereochemical information is ultimately of enzymatic origin
Response of the Jovian thermosphere to a transient ‘pulse’ in solar wind pressure

AbstractThe importance of the Jovian thermosphere with regard to magnetosphere–ionosphere coupling is often neglected in magnetospheric physics. We present the first study to investigate the response of the Jovian thermosphere to transient variations in solar wind dynamic pressure, using an azimuthally symmetric global circulation model coupled to a simple magnetosphere and fixed auroral conductivity model. In our simulations, the Jovian magnetosphere encounters a solar wind shock or rarefaction region and is subsequently compressed or expanded. We present the ensuing response of the coupling currents, thermospheric flows, heating and cooling terms, and the aurora to these transient events. Transient compressions cause the reversal, with respect to steady state, of magnetosphere–ionosphere coupling currents and momentum transfer between the thermosphere and magnetosphere. They also cause at least a factor of two increase in the Joule heating rate. Ion drag significantly changes the kinetic energy of the thermospheric neutrals depending on whether the magnetosphere is compressed or expanded. Local temperature variations appear between ~−45and175K for the compression scenario and ~−20and50K for the expansion case. Extended regions of equatorward flow develop in the wake of compression events – we discuss the implications of this behaviour for global energy transport. Both compressions and expansions lead to a ~2000TW increase in the total power dissipated or deposited in the thermosphere. In terms of auroral processes, transient compressions increase main oval UV emission by a factor of ~4.5 whilst transient expansions increase this main emission by a more modest 37%. Both types of transient event cause shifts in the position of the main oval, of up to 1° latitude
Signatures of material and optical chirality: Origins and measures

AbstractChirality in materials and light is of abiding interest across a broad range of scientific disciplines. This article discusses present and emerging issues in relation to molecular and optical chirality, also including some important developments in chiral metamaterials. Quantifying the chirality of matter or light leads to issues concerning the most appropriate measures, such as a helicity parameter for specific chiral chromophores and technical measures of light chirality. An optical helicity and chirality density depend on a difference between the numbers of left- and right-handed photons in a beam. In connection with circularly polarised luminescence, adoption of the Stokes parameter to spontaneous emission from chiral molecules invites critical attention. Modern spectroscopic techniques are often based on the different response arising from left-handed circularly polarised light compared to right-handed light. This dissimilarity can be exploited as a foundation for the separation of chiral molecules, promising new avenues of application
Casimir energy–momentum tensor for a brane in de Sitter spacetime

AbstractVacuum expectation values of the energy–momentum tensor for a conformally coupled scalar field are investigated in de Sitter (dS) spacetime in presence of a curved brane on which the field obeys the Robin boundary condition with coordinate dependent coefficients. To generate the corresponding vacuum densities we use the conformal relation between dS and Rindler spacetimes and the results previously obtained by one of the authors for the Rindler counterpart. The resulting energy–momentum tensor is non-diagonal and induces anisotropic vacuum stresses. The asymptotic behaviour of this tensor is investigated near the dS horizon and the boundary
Nitrosopersulfide (SSNO−) accounts for sustained NO bioactivity of S-nitrosothiols following reaction with sulfide

AbstractSulfide salts are known to promote the release of nitric oxide (NO) from S-nitrosothiols and potentiate their vasorelaxant activity, but much of the cross-talk between hydrogen sulfide and NO is believed to occur via functional interactions of cell regulatory elements such as phosphodiesterases. Using RFL-6 cells as an NO reporter system we sought to investigate whether sulfide can also modulate nitrosothiol-mediated soluble guanylyl cyclase (sGC) activation following direct chemical interaction. We find a U-shaped dose response relationship where low sulfide concentrations attenuate sGC stimulation by S-nitrosopenicillamine (SNAP) and cyclic GMP levels are restored at equimolar ratios. Similar results are observed when intracellular sulfide levels are raised by pre-incubation with the sulfide donor, GYY4137. The outcome of direct sulfide/nitrosothiol interactions also critically depends on molar reactant ratios and is accompanied by oxygen consumption. With sulfide in excess, a ‘yellow compound’ accumulates that is indistinguishable from the product of solid-phase transnitrosation of either hydrosulfide or hydrodisulfide and assigned to be nitrosopersulfide (perthionitrite, SSNO−; λmax 412nm in aqueous buffers, pH 7.4; 448nm in DMF). Time-resolved chemiluminescence and UV–visible spectroscopy analyses suggest that its generation is preceded by formation of the short-lived NO-donor, thionitrite (SNO−). In contrast to the latter, SSNO− is rather stable at physiological pH and generates both NO and polysulfides on decomposition, resulting in sustained potentiation of SNAP-induced sGC stimulation. Thus, sulfide reacts with nitrosothiols to form multiple bioactive products; SSNO− rather than SNO− may account for some of the longer-lived effects of nitrosothiols and contribute to sulfide and NO signaling
Diet-Dependent Effects of the Drosophila Mnk1/Mnk2 Homolog Lk6 on Growth via eIF4E

AbstractThe control of cellular growth is tightly linked to the regulation of protein synthesis. A key function in translation initiation is fulfilled by the 5′ cap binding eukaryotic initiation factor 4E (eIF4E), and dysregulation of eIF4E is associated with malignant transformation and tumorigenesis [1, 2]. In mammals, the activity of eIF4E is modulated by phosphorylation at Ser209 by mitogen-activated protein kinases (MAPK)-interacting kinases 1 and 2 (Mnk1 and Mnk2) [3–5], which themselves are activated by ERK and p38 MAPK in response to mitogens, cytokines or cellular stress [6]. Whether phosphorylation of eIF4E at Ser209 exerts a positive or inhibitory effect on translation efficiency has remained controversial. Here we provide a genetic characterization of the Drosophila homolog of Mnk1/2, Lk6. Lk6 function is dispensable under a high protein diet, consistent with the recent finding that mice lacking both Mnk1 and Mnk2 are not growth-impaired [4]. Interestingly, loss of Lk6 function causes a significant growth reduction when the amino acid content in the diet is reduced. Overexpression of Lk6 also results in growth inhibition in an eIF4E-dependent manner. We propose a model of eIF4E regulation that may reconcile the contradictory findings with regard to the role of phosphorylation by Mnk1/2
Diffractive dissociation of gluons into heavy quark–antiquark pairs in proton–proton collisions

AbstractWe discuss diffractive dissociation of gluons into heavy quark pairs. The particular mechanism is similar to the diffractive dissociation of virtual photons into quarks, which drives diffractive deep inelastic production of charm in the low-mass diffraction, or large β-region. There, it can be understood, with some reservations, in terms of a valence heavy quark content of the Pomeron. The amplitude for the gp→QQ¯p is derived in the impact parameter and momentum space. The cross section for single diffractive pp→QQ¯pX is calculated as a convolution of the elementary cross section and gluon distribution in the proton. Integrated cross section and the differential distributions in e.g. transverse momentum and rapidity of the charm and bottom quark and antiquark, as well as the quark–antiquark invariant mass are calculated for the nominal LHC energy for different unintegrated gluon distributions from the literature. The ratio of the bottom-to-charm cross sections are shown and discussed as a function of several kinematical variables
Increasing Scientific Confidence in Adverse Outcome Pathways: Application of Tailored Bradford-Hill Considerations for Evaluating Weight of Evidence

AbstractSystematic consideration of scientific support is a critical element in developing and, ultimately, using adverse outcome pathways (AOPs) for various regulatory applications. Though weight of evidence (WoE) analysis has been proposed as a basis for assessment of the maturity and level of confidence in an AOP, methodologies and tools are still being formalized. The Organization for Economic Co-operation and Development (OECD) Users’ Handbook Supplement to the Guidance Document for Developing and Assessing AOPs (OECD 2014a; hereafter referred to as the OECD AOP Handbook) provides tailored Bradford-Hill (BH) considerations for systematic assessment of confidence in a given AOP. These considerations include (1) biological plausibility and (2) empirical support (dose-response, temporality, and incidence) for Key Event Relationships (KERs), and (3) essentiality of key events (KEs). Here, we test the application of these tailored BH considerations and the guidance outlined in the OECD AOP Handbook using a number of case examples to increase experience in more transparently documenting rationales for assigned levels of confidence to KEs and KERs, and to promote consistency in evaluation within and across AOPs. The major lessons learned from experience are documented, and taken together with the case examples, should contribute to better common understanding of the nature and form of documentation required to increase confidence in the application of AOPs for specific uses. Based on the tailored BH considerations and defining questions, a prototype quantitative model for assessing the WoE of an AOP using tools of multi-criteria decision analysis (MCDA) is described. The applicability of the approach is also demonstrated using the case example aromatase inhibition leading to reproductive dysfunction in fish. Following the acquisition of additional experience in the development and assessment of AOPs, further refinement of parameterization of the model through expert elicitation is recommended. Overall, the application of quantitative WoE approaches hold promise to enhance the rigor, transparency and reproducibility for AOP WoE determinations and may play an important role in delineating areas where research would have the greatest impact on improving the overall confidence in the AOP
Quantifying human sensitivity to spatio-temporal information in dynamic faces

AbstractA great deal of perceptual and social information is conveyed by facial motion. Here, we investigated observers’ sensitivity to the complex spatio-temporal information in facial expressions and what cues they use to judge the similarity of these movements. We motion-captured four facial expressions and decomposed them into time courses of semantically meaningful local facial actions (e.g., eyebrow raise). We then generated approximations of the time courses which differed in the amount of information about the natural facial motion they contained, and used these and the original time courses to animate an avatar head. Observers chose which of two animations based on approximations was more similar to the animation based on the original time course. We found that observers preferred animations containing more information about the natural facial motion dynamics. To explain observers’ similarity judgments, we developed and used several measures of objective stimulus similarity. The time course of facial actions (e.g., onset and peak of eyebrow raise) explained observers’ behavioral choices better than image-based measures (e.g., optic flow). Our results thus revealed observers’ sensitivity to changes of natural facial dynamics. Importantly, our method allows a quantitative explanation of the perceived similarity of dynamic facial expressions, which suggests that sparse but meaningful spatio-temporal cues are used to process facial motion
Myers–Perry black holes with scalar hair and a mass gap

AbstractWe construct a family of asymptotically flat, rotating black holes with scalar hair and a regular horizon, within five dimensional Einstein's gravity minimally coupled to a complex, massive scalar field doublet. These solutions are supported by rotation and have no static limit. They are described by their mass M, two equal angular momenta J1=J2≡J and a conserved Noether charge Q, measuring the scalar hair. For vanishing horizon size the solutions reduce to five dimensional boson stars. In the limit of vanishing Noether charge density, the scalar field becomes point-wise arbitrarily small and the geometry becomes, locally, arbitrarily close to that of a specific set of Myers–Perry black holes (MPBHs); but there remains a global difference with respect to the latter, manifest in a finite mass gap. Thus, the scalar hair never becomes a linear perturbation of MPBHs. This is a qualitative difference when compared to Kerr black holes with scalar hair [1]. Whereas the existence of the latter can be anticipated in linear theory, from the existence of scalar bound states on the Kerr geometry (i.e. scalar clouds), the hair of these MPBHs is intrinsically non-linear
Weak KAM aspects of convex Hamilton–Jacobi equations with Neumann type boundary conditions

AbstractWe study convex Hamilton–Jacobi equations H(x,Du)=0 and ut+H(x,Du)=0 in a bounded domain Ω of Rn with the Neumann type boundary condition Dγu=g in the viewpoint of weak KAM theory, where γ is a vector field on the boundary ∂Ω pointing a direction oblique to ∂Ω. We establish the stability under the formations of infimum and of convex combinations of subsolutions of convex Hamilton–Jacobi equations, some comparison and existence results for convex and coercive Hamilton–Jacobi equations with the Neumann type boundary condition as well as existence results for the Skorokhod problem. We define the Aubry set associated with the Neumann type boundary problem and establish some properties of the Aubry set including the existence results for the “calibrated” extremals for the corresponding action functional (or variational problem)
Tevatron Higgs mass bounds: Projecting U(1)′ models to LHC domain

AbstractWe study Higgs boson masses in supersymmetric models with an extra U(1) symmetry to be called U(1)′. Such extra gauge symmetries are urged by the μ problem of the MSSM, and they also arise frequently in low-energy supersymmetric models stemming from GUTs and strings.We analyze mass of the lightest Higgs boson and various other particle masses and couplings by taking into account the LEP bounds as well as the recent bounds from Tevatron experiments. We find that the μ-problem motivated generic low-energy U(1)′ model yields Higgs masses as large as ∼200 GeV and violate the Tevatron bounds for certain ranges of parameters. We analyze correlations among various model parameters, and determine excluded regions by both scanning the parameter space and by examining certain likely parameter values. We also make educated projections for LHC measurements in light of the Tevatron restrictions on the parameter space.We further analyze certain benchmark models stemming from E(6) breaking, and find that they elevate Higgs boson mass into Tevatron's forbidden band when U(1)′ gauge coupling takes larger values than the one corresponding to one-step GUT breaking