Energy and system size dependence of charged particle elliptic flow and v_2/\eps scaling

We report measurements of charged particle elliptic flow %($v_2$) at mid-rapidity in Au+Au and Cu+Cu collisions at $\sqrt{s_{_{NN}}}=62$ and 200 GeV. Using correlations between main STAR TPC and Forward TPCs ensures minimal bias due to non-flow effects. We further investigate the effect of flow fluctuations on v_2/\eps scaling studying initial geometry eccentricity fluctuations in Monte-Carlo Glauber model, consistent with STAR direct measurements of elliptic flow fluctuations. It is found that accounting for the effect of flow fluctuations improves v_2/\eps scaling.Comment: 4 pages, Quark Matter 2006 proceeding

Extract of Combretum micranthum as corrosion inhibitor for Al – Si – Mg alloy in simulated sea water environment

The leaf extract  of  Combretum micranthum (CM) was  tested  as  green  corrosion  inhibitor for Al-Si-Mg alloy in 3.5wt% NaCl solution using gravimetric and linear polarization methods at 300C, 500C and 700C, from 1, 2, 3, 4, 5 hours of exposure time with concentration of the extract 0, 0.2, 0.4, 0.6, 0.8 and 1.0 v/v  respectively. The result obtained indicate that the leaf extract of CM is a good corrosion inhibitor in the simulated sea  water medium. The inhibition efficiency of the extract increased with an increase in concentration of the CM extract and decreased with increase in temperature. On the other hand, inhibition efficiency (IE%) synergistically decreased on addition of surfactant (Monoethylamine). The adsorption of the inhibitor on Al-Si-Mg surface is exothermic, Spontaneous and is best described by Langmuir, Freundlick and El-Awady adsorption models. The calculated values of activation energy, enthalpy of activation entropy of activation, free energy of process is by physical adsorption. Equally, methanol extract CM is a good adsorption inhibitor for the corrosion of Al-Si-Mg in 3.5wt% NaCl solution. Tafel polarization analysis indicates that the studied plant extract is a mixed type inhibitor. http://dx.doi.org/10.4314/njt.v35i4.2

Theoretical analysis for the apparent discrepancy between pbarp and pp data in charged particle forward-backward multiplicity correlations

The strength of charged particle forward-backward multiplicity correlation in pbar+p and p+p collisions at s^1/2 = 200 GeV is studied by PYTHIA 6.4 and compared to the UA5 and STAR data correspondingly. It is turned out that a factor of 3-4 apparent discrepancy between UA5 and STAR data can be attributed to the differences in detector acceptances and observing bin interval in both experiments. A mixed event method is introduced and used to calculate the statistical correlation strength and the dynamical correlation strengths stemming from the charge conservation, four- momentum conservation, and decay, respectively. It seems that the statistical correlation is much larger than dynamical one and the charge conservation, four-momentum conservation and decay may account for most part of the dynamical correlation. In addition, we have also calculated the correlation strength by fitting the charged particle multiplicity distribution from PYTHIA to the Negative Binomial Distribution and found that the result agrees well with the correlation strength calculated by mixed events.Comment: 5 pages, 4 figure

Shear Modes, Criticality and Extremal Black Holes

We consider a (2+1)-dimensional field theory, assumed to be holographically dual to the extremal Reissner-Nordstrom AdS(4) black hole background, and calculate the retarded correlators of charge (vector) current and energy-momentum (tensor) operators at finite momentum and frequency. We show that, similar to what was observed previously for the correlators of scalar and spinor operators, these correlators exhibit emergent scaling behavior at low frequency. We numerically compute the electromagnetic and gravitational quasinormal frequencies (in the shear channel) of the extremal Reissner-Nordstrom AdS(4) black hole corresponding to the spectrum of poles in the retarded correlators. The picture that emerges is quite simple: there is a branch cut along the negative imaginary frequency axis, and a series of isolated poles corresponding to damped excitations. All of these poles are always in the lower half complex frequency plane, indicating stability. We show that this analytic structure can be understood as the proper limit of finite temperature results as T is taken to zero holding the chemical potential fixed.Comment: 28 pages, 7 figures, added reference

The QGP phase in relativistic heavy-ion collisions

The dynamics of partons, hadrons and strings in relativistic nucleus-nucleus collisions is analyzed within the novel Parton-Hadron-String Dynamics (PHSD) transport approach, which is based on a dynamical quasiparticle model for partons (DQPM) matched to reproduce recent lattice-QCD results - including the partonic equation of state - in thermodynamic equilibrium. The transition from partonic to hadronic degrees of freedom is described by covariant transition rates for the fusion of quark-antiquark pairs or three quarks (antiquarks), respectively, obeying flavor current-conservation, color neutrality as well as energy-momentum conservation. The PHSD approach is applied to nucleus-nucleus collisions from low SIS to RHIC energies. The traces of partonic interactions are found in particular in the elliptic flow of hadrons as well as in their transverse mass spectra.Comment: To be published by Springer in Proceedings of the International Symposium on `Exciting Physics', Makutsi-Range, South Africa, 13-20 November, 201

Bosonic Fractionalisation Transitions

At finite density, charge in holographic systems can be sourced either by explicit matter sources in the bulk or by bulk horizons. In this paper we find bosonic solutions of both types, breaking a global U(1) symmetry in the former case and leaving it unbroken in the latter. Using a minimal bottom-up model we exhibit phase transitions between the two cases, under the influence of a relevant operator in the dual field theory. We also embed solutions and transitions of this type in M-theory, where, holding the theory at constant chemical potential, the cohesive phase is connected to a neutral phase of Schr\"odinger type via a z=2 QCP.Comment: references added. minor changes. version published in JHE

TEMPRANILLO is a regulator of juvenility in plants

Many plants are incapable of flowering in inductive daylengths during the early juvenile vegetative phase (JVP). Arabidopsis mutants with reduced expression of TEMPRANILLO (TEM), a repressor of FLOWERING LOCUS T (FT) had a shorter JVP than wild-type plants. Reciprocal changes in mRNA expression of TEM and FT were observed in both Arabidopsis and antirrhinum, which correlated with the length of the JVP. FT expression was induced just prior to the end of the JVP and levels of TEM1 mRNA declined rapidly at the time when FT mRNA levels were shown to increase. TEM orthologs were isolated from antirrhinum (AmTEM) and olive (OeTEM) and were expressed most highly during their juvenile phase. AmTEM functionally complemented AtTEM1 in the tem1 mutant and over-expression of AmTEM prolonged the JVP through repression of FT and CONSTANS (CO). We propose that TEM may have a general role in regulating JVP in herbaceous and woody species

Ceramides: a new player in the inflammation-insulin resistance paradigm?

No abstract available