Holographic Oddballs

The spectrum of the glueball with $J^{PC}=0^{--}$ is computed using different bottom-up holographic models of QCD. The results indicate a lowest-lying state lighter than in the determination by other methods, with mass $m \simeq 2.8$ GeV. The in-medium properties of this gluonium are investigated, and stability against thermal and density effects is compared to other hadronic systems. Production and decay modes are identified, useful for searching the $J^{PC}=0^{--}$ glueball.Comment: 16 pages, 9 figures, 3 table

On thermalization of a boost-invariant non Abelian plasma

Using a holographic method, we further investigate the relaxation towards the hydrodynamic regime of a boost-invariant non-Abelian plasma taken out-of-equilibrium. In the dual description, the system is driven out-of-equilibrium by boundary sourcing, a deformation of the boundary metric, as proposed by Chesler and Yaffe. The effects of several deformation profiles on the bulk geometry are investigated by the analysis of the corresponding solutions of the Einstein equations. The time of restoration of the hydrodynamic regime is investigated: setting the effective temperature of the system at the end of the boundary quenching to $T_{eff}(\tau^*)=500$ MeV, the hydrodynamic regime is reached after a lapse of time of ${\cal O}$(1 fm/c).Comment: 24 pages, 11 figures. Improved numerical analysis, one more appendix, two new figures. To appear in JHE

Quarkonium dissociation in a far-from-equilibrium holographic setup

The real-time dissociation of the heavy quarkonium in a strongly coupled boost-invariant non-Abelian plasma relaxing towards equilibrium is analyzed in a holographic framework. The effects driving the plasma out of equilibrium are described by boundary quenching, impulsive variations of the boundary metric. Quarkonium is represented by a classical string with endpoints kept close to the boundary. The evolution of the string profile is computed in the time-dependent geometry, and the dissociation time is evaluated for different configurations with respect to the direction of the plasma expansion. Dissociation occurs fastly for the quarkonium placed in the transverse plane.Comment: 14 pages, 8 figures. References added. Matches the published versio

Quarkonium dissociation in strongly coupled far-from-equilibrium matter: holographic description

Abstract The heavy quarkonium real-time dissociation in a strongly coupled non-Abelian matter relaxing to equilibrium is described in a holographic approach. Boundary sourcing, impulsive distortions of the boundary metric, are used to mimic effects driving the matter far-from-equilibrium. Quarkonium is represented by a string with endpoints kept close to the boundary, and its evolution in the time-dependent geometry is studied

Accurate noninvasive estimation of pulmonary vascular resistance by Doppler echocardiography in patients with chronic heart failure

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Doppler-derived mitral deceleration time of early filling as a strong predictor of pulmonary capillary wedge pressure in postinfarction patients with left ventricular systolic dysfunction

AbstractObjectives. The aim of this study was to investigate the correlations between Doppler-derlved transmitral flow velocity variables and pulmonary capillary wedge pressure in patients with severe left ventricular systolic dysfunction.Background. Abnormal relaxation and increased chamber stiffness have opposing effects on the left ventricular filling pattern. When both abnormalities are present at the same time, as often occurs in patients with systolic dysfunction, the ability of Doppler recording to assess diastolic function and predict left ventricular fillng pressure may be significantly compromised.Method. Pulmonary capillary wedge pressure and Doppler transmitral flow velocity profile were simultaneously recorded in 140 postinfarction patients with ejection fraction ≤35%.Results. Correlation between the ratio of mitral peak low velocity in early diastole to peak low velocity in late diastole (E/A ratio) and pulmonary capillary wedge pressure was weak (r = 0.65). Although the specificity of E/A ≥ 2 in predicting ≥29 mm Hg in pulmonary capillary wedge pressure was high (99%), its sensitivity was low (43%). Conversely, a very close negative correlation was found between mitral deceleration time of early filling and pulmonary capillary wedge pressure (r = −0.91). Sensitivity and specificity of ≤120 ms in deceleration time in predicting ≥20 mm Hg in pulmonary capillary wedge pressure were 100% and 99%, respectively.Conclusions. Doppler-derived mitral deceleration time of early filling provides a simple and accurate means of estimating pulmonary capillary wedge pressure that is particularly useful in patients with a normal or normalized mitral low velocity pattern

Occurrence of Toxic Cyanobacterial Blooms in Rio de la Plata Estuary, Argentina: Field Study and Data Analysis

Water samples were collected during 3 years (2004–2007) at three sampling sites in the Rio de la Plata estuary. Thirteen biological, physical, and chemical parameters were determined on the water samples. The presence of microcystin-LR in the reservoir samples, and also in domestic water samples, was confirmed and quantified. Microcystin-LR concentration ranged between 0.02 and 8.6 μg.L−1. Principal components analysis was used to identify the factors promoting cyanobacteria growth. The proliferation of cyanobacteria was accompanied by the presence of high total and fecal coliforms bacteria (>1500 MNP/100 mL), temperature ≥25°C, and total phosphorus content ≥1.24 mg·L−1. The observed fluctuating patterns of Microcystis aeruginosa, total coliforms, and Microcystin-LR were also described by probabilistic models based on the log-normal and extreme value distributions. The sampling sites were compared in terms of the distribution parameters and the probability of observing high concentrations for Microcystis aeruginosa, total coliforms, and microcystin-LR concentration

Short and long term surface chemistry and wetting behaviour of stainless steel with 1D and 2D periodic structures induced by bursts of femtosecond laser pulses

We investigate the short and long term wettability of laser textured stainless steel samples in order to better understand the interplay between surface topography and chemistry. Very different 1D and 2D periodic as well as non-periodic surface patterns were produced by exploiting the extreme flexibility of a setup consisting of five rotating birefringent crystals, which allows generating bursts of up to 32 femtosecond laser pulses with fixed intra-burst delay of 1.5 ps. The change of the surface morphology as a function of the pulse splitting, the burst polarization state and the fluence was systematically studied. The surface topography was characterized by SEM and AFM microscopy. The laser textured samples exhibited, initially, superhydrophilic behaviour which, during exposure to ambient air, turned into superhydrophobic with an exponential growth of the static contact angle. The dynamic contact angle measurements revealed a water adhesive character which was explained by XPS analyses of the surfaces that showed an increase of hydrocarbons and more oxidized metal species with the aging. The characteristic water adhesiveness and superhydrophobicity of laser textured surfaces can be exploited for no loss droplet reversible transportation or harvesting

Effects of diffusion induced recrystallization on volume diffusion in the copper-nickel system

Abstract The effects of diffusion induced recrystallization (DIR) on volume diffusion in the Cu(Ni) system was investigated. Cu-Ni diffusion couples annealed at 500, 550, 600, and 650°C for 120 and 200 h were used to calculate the volume diffusion for the Cu(Ni) binary system. Using characterization techniques such as focused ion beam (FIB) and transmission electron microscopy (TEM), observation of the interdiffusion zone revealed areas containing DIR and non-DIR. The volume diffusion of Ni into Cu across the non-DIR regions were calculated using the Boltzmann-Matano (B/M) method at 1 wt% Ni to be 8.05E-21, 9.88E-20, 4.53E-19, 2.67E-18 m 2 /s for 500, 550, 600, and 650°C, respectively. Calculations of volume diffusion across the DIR zones were approximately three to four orders of magnitude higher than the volume diffusion based on the non-DIR information. Literature values for volume diffusion in the Cu(Ni) system are also higher than the non-DIR values by approximately one order of magnitude, implying that previous values may contain grain boundary contributions