Stellar kinematics and populations out to 1.5 effective radius in the elliptical galaxy NGC4636

We present high quality long slit spectra along the major and minor axes out to 1.5 effective radius ($R_e$) of the massive galaxy NGC4636 taken by Hobby-Eberly Telescope (HET). Using Fourier Correlation Quotient (FCQ) method, we measured the stellar line-of-sight velocity distribution along the axes. Furthermore, six Lick/IDS indices ($H\beta,Mgb,Fe_{5015},Fe_{5270},Fe_{5335},Fe_{5406}$) are derived from the clean spectrum. By comparing the measured absorption line strengths with the predictions of Simple Stellar Populations (SSP) models, we derived ages, total metallicity and $\alpha$ abundance profiles of the galaxy. This galaxy presents old and $[\alpha/Fe]$ over abundant stellar populations. Indeed, using the SSP model, we obtained the broadband color profiles. The theoretical colors match well with the measured colors and present red sharp peaks at the galaxy center. The sharp peaks of the colors are mainly shaped by the high metallicity in the galaxy center. Interestingly, the galaxy has steep negative metallicity gradients, but trend flattens outwards. This result likly suggests that the center and outer regions of the galaxy formed through different formation process.Comment: 14 pages, 7 figures, accepted by RA

The effects of a dietary excess of leucine on the synthesis of nicotinamide nucleotides in the rat

1. In order to test the suggestion that a dietary excess of leucine may be a precipitating factor in pellagra, rats were fed on diets that provided 15 g leucine/kg in excess of requirements for 7 weeks from weaning. This led to a significant reduction in the concentrations of nicotinamide nucleotides in liver and blood. The effect was only apparent when the diets provided less than a minimally adequate amount of nicotinamide, so that the animals were dependent on the synthesis of nicotinamide nucleotides from tryptophan to meet all or part of their requirements. 2. Urinary excretion of N1-methyl nicotinamide was not a useful indicator of tissue concentrations of nicotinamide nucleotides, and seemed not to be adequately sensitive to differentiate between minimal adequacy and marginal deficiency, as demonstrated by changes in concentrations of nicotinamide nucleotides in liver and blood. 3. The addition of leucine to incubation media for the measurement of enzyme activity in tissue homogenates at concentrations within the physiological range, led to a significant activation of tryptophan oxygenase (L-tryptophan: oxygen oxidoreductase (decyclizing), EC 1.13.11.11) and significant inhibition of kynureninase (L-kynurenine hydrolase, EC 3.7.1.3). The effect on tryptophan oxygenase may not be physiologically significant, in view of the considerable range of activity of this enzyme under normal conditions. However, the inhibition of kynureninase, which was primarily competitive with respect to the substrate, probably is physiologically significant, and was enough for this enzyme to become a probable rate-limiting step in tryptophan metabolism and nicotinamide nucleotide synthesis. Other enzymes of the tryptophan – nicotinamide nucleotide pathway were not affected by the addition of leucine to the incubation medium. 4. Feeding 15 g leucine/kg diet in excess of minimum requirements had no effect on the activities of tryptophan oxygenase or kynureninase in liver homogenates. This may reflect the reversible competitive nature of the inhibition of kynureninase by leucine, and hence be an artefact of the incubation procedure. Rats fed on the high-leucine diets excreted significantly more kynurenine than did control animals, which is evidence of inhibition of kynureninase in vivo. 5. It appears that a dietary excess of leucine, of the order of 15 g/kg above requirements, may be a precipitating factor in pellagra when there is reliance on the synthesis of nicotinamide nucleotides from tryptophan to meet a part or all of the requirements, but not when minimally adequate niacin is available from the diet

Guiding structures with multiply connected cross-sections: evolution of propagation in external fields at complex Robin parameters

Properties of the two-dimensional ring and three-dimensional infinitely long straight hollow waveguide with unit width and inner radius $\rho_0$ in the superposition of the longitudinal uniform magnetic field $\bf B$ and Aharonov-Bohm flux are analyzed within the framework of the scalar Helmholtz equation under the assumption that the Robin boundary conditions at the inner and outer confining walls contain extrapolation lengths $\Lambda_{in}$ and $\Lambda_{out}$, respectively, with nonzero imaginary parts. It is shown that, compared to the disk geometry, the annulus opens up additional possibilities of varying magnetization and currents by tuning imaginary components of the Robin parameters on each confining circumference; in particular, the possibility of restoring a lossless longitudinal flux by zeroing imaginary part $E_i$ of the total transverse energy $E$ is discussed. The energy $E$ turns real under special correlation between the imaginary parts of $\Lambda_{in}$ and $\Lambda_{out}$ with the opposite signs what physically corresponds to the equal transverse fluxes through the inner and outer interfaces of the annulus. In the asymptotic case of the very large radius, simple expressions are derived and applied to the analysis of the dependence of the real energy $E$ on $\Lambda_{in}$ and $\Lambda_{out}$. New features also emerge in the magnetic field influence; for example, if, for the quantum disk, the imaginary energy $E_i$ is quenched by the strong intensities $B$, then for the annulus this takes place only when the inner Robin distance $\Lambda_{in}$ is real; otherwise, it almost quadratically depends on $B$ with the corresponding enhancement of the reactive scattering. Closely related problem of the hole in the otherwise uniform medium is also addressed for real and complex extrapolation lengths with the emphasis on the comparative analysis with its dot counterpart.Comment: 37 pages, 9 figure

Probable mechanisms of regulation of the utilization of dietary tryptophan, nicotinamide and nicotinic acid as precursors of nicotinamide nucleotides in the rat

1. The regulation of the utilization of dietary tryptophan, nicotinamide and nicotinic acid as precursors of the nicotinamide nucleotides has been studied in groups of rats fed on diets providing only one of these precursors at a time, in amounts adequate to meet their requirements for nucleotide synthesis. 2. The concentration of nicotinamide nucleotides in the liver of rats receiving a high-tryptophan diet was 56% higher than in animals fed on a diet providing a minimum amount of tryptophan, together with nicotinic acid or nicotinamide. The excretion of N1-methyl nicotinamidc was three times higher in the tryptophan-fed animals than in the other two groups. 3. The concentration of quinolinic acid in the liver was significantly higher in animals receiving the high-tryptophan diet than in the other two groups; that of nicotinic acid was highest in those animals receiving the nicotinic-acid-containing diet. The concentration of nicotinamide was highest in the livers of those animals receiving the high-tryptophan diet, and lowest in those receiving the nicotinic-acid-contaning diet. 4. The values of the Michaelis constant Km of nicotinamide deamidase (nicotinamide amidohydrolase. EC 3.5,1,19) and nicotinamide phosphoribosylltransferase (nicotinamide nucleotide: pyrophosphate phosphoribosyltransferase, EC 2.4.2.12) were approximately equal, and approximately one-tenth of the concentration of nicotinamide was in the liver. This suggests that both these enzymes normally function at their maximum rate, and a change in the availability of nicotinamide would not affect the rate of its incorporation into nucleotides. 5. The maximum rate of reaction (Vmax) of nicotinamide deamidase was twice that of nicotinamide phosphoribosyltransferase; this suggests that unless compartmental or other factors are involved, the major route of nicotinamide utilization will be by way of deamidation. 6. The Km of nicotinate phosphoribosyltransferase (nicotinate nucleotide: pyrophosphate phosphoribosyltransferase, EC 2.4.2.11) was less than twice the concentration of nicotinic acid in the liver, so that a change in the availability of nicotinic acid might be expected to lead to a small change in the rate of its utilization. 7. The Km of quinolinate phosphoribosyltransferase (nicotinate nucleotide: pyrophosphate phosphoribosyltransferase (carboxylating) EC 2.4.2.19) was approximately 100 times greater than the concentration of quinolinic acid in the liver, so that any change in the availability of quinolinic acid would be expected to lead to a considerable change in the rate of its utilization. The Vmax of quinolinate phosphoribosyltransferase was relatively low, so that under conditions of high tryptophan flux, some accumulation of quinolinic acid might be expected. This was observed in animals receiving the high-tryptophan diet. 8. It is concluded that it is unlikely that the utilization of quinolinic acid, arising from tryptophan. for the synthesis of nicotinamide nucleotides is regulated, but that control over tissue concentrations of nucleotides is achieved by hydrolysis of NAD to nicotinamide. Incorporation of nicotinamide into nucleotides seems to be strictly limited by the activity of the enzymes involved

Measurement of the t¯tZ and t¯tW cross sections in proton-proton collisions at √s=13 TeV with the ATLAS detector

A measurement of the associated production of a top-quark pair (t¯t) with a vector boson (W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV is presented, using 36.1  fb−1 of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. Events are selected in channels with two same- or opposite-sign leptons (electrons or muons), three leptons or four leptons, and each channel is further divided into multiple regions to maximize the sensitivity of the measurement. The t¯tZ and t¯tW production cross sections are simultaneously measured using a combined fit to all regions. The best-fit values of the production cross sections are σt¯tZ=0.95±0.08stat±0.10syst pb and σt¯tW=0.87±0.13stat±0.14syst pb in agreement with the Standard Model predictions. The measurement of the t¯tZ cross section is used to set constraints on effective field theory operators which modify the t¯tZ vertex

Study of the hard double-parton scattering contribution to inclusive four-lepton production in pp collisions at √s=8 TeV with the ATLAS detector

The inclusive production of four isolated charged leptons in pp collisions is analysed for the presence of hard double-parton scattering, using 20.2fb−1of data recorded in the ATLAS detector at the LHC at centre-of-mass energy √s=8TeV. In the four-lepton invariant-mass range of 80 <m4<1000GeV, an artificial neural network is used to enhance the separation between single-and double-parton scattering based on the kinematics of the four leptons in the final state. An upper limit on the fraction of events originating from double-parton scattering is determined at 95% confidence level to be fDPS=0.042, which results in an estimated lower limit on the effective cross section at 95% confidence level of 1.0mb

Search for large missing transverse momentum in association with one top-quark in proton-proton collisions at √s = 13 TeV with the ATLAS detector

This paper describes a search for events with one top-quark and large missing transverse momentum in the final state. Data collected during 2015 and 2016 by the ATLAS experiment from 13 TeV proton–proton collisions at the LHC corresponding to an integrated luminosity of 36.1 fb−1 are used. Two channels are considered, depending on the leptonic or the hadronic decays of the W boson from the top quark. The obtained results are interpreted in the context of simplified models for dark-matter production and for the single production of a vector-like T quark. In the absence of significant deviations from the Standard Model background expectation, 95% confidence-level upper limits on the corresponding production cross-sections are obtained and these limits are translated into constraints on the parameter space of the models considered

Electron and photon energy calibration with the ATLAS detector using 2015–2016 LHC proton-proton collision data

This paper presents the electron and photon energy calibration obtained with the ATLAS detector using about 36 fb−1 of LHC proton-proton collision data recorded at √s = 13 TeV in 2015 and 2016. The different calibration steps applied to the data and the optimization of the reconstruction of electron and photon energies are discussed. The absolute energy scale is set using a large sample of Z boson decays into electron-positron pairs. The systematic uncertainty in the energy scale calibration varies between 0.03% to 0.2% in most of the detector acceptance for electrons with transverse momentum close to 45 GeV. For electrons with transverse momentum of 10 GeV the typical uncertainty is 0.3% to 0.8% and it varies between 0.25% and 1% for photons with transverse momentum around 60 GeV. Validations of the energy calibration with J/ψ → e + e − decays and radiative Z boson decays are also presented

Performance of top-quark and W -boson tagging with ATLAS in Run 2 of the LHC

The performance of identification algorithms (“taggers”) for hadronically decaying top quarks and W bosons in pp collisions at √s=13 TeV recorded by the ATLAS experiment at the Large Hadron Collider is presented. A set of techniques based on jet shape observables are studied to determine a set of optimal cut-based taggers for use in physics analyses. The studies are extended to assess the utility of combinations of substructure observables as a multivariate tagger using boosted decision trees or deep neural networks in comparison with taggers based on two-variable combinations. In addition, for highly boosted top-quark tagging, a deep neural network based on jet constituent inputs as well as a re-optimisation of the shower deconstruction technique is presented. The performance of these taggers is studied in data collected during 2015 and 2016 corresponding to 36.1 fb −1 for the tt ¯ and γ+jet and 36.7 fb −1 −1 for the dijet event topologies

The Kuramoto model in complex networks

181 pages, 48 figures. In Press, Accepted Manuscript, Physics Reports 2015 Acknowledgments We are indebted with B. Sonnenschein, E. R. dos Santos, P. Schultz, C. Grabow, M. Ha and C. Choi for insightful and helpful discussions. T.P. acknowledges FAPESP (No. 2012/22160-7 and No. 2015/02486-3) and IRTG 1740. P.J. thanks founding from the China Scholarship Council (CSC). F.A.R. acknowledges CNPq (Grant No. 305940/2010-4) and FAPESP (Grants No. 2011/50761-2 and No. 2013/26416-9) for financial support. J.K. would like to acknowledge IRTG 1740 (DFG and FAPESP).Peer reviewedPreprin