Myocardial fibrosis in stroke survivors

Stroke survivors are most likely to die of cardiac death, yet few undergo comprehensive cardiac assessment to look for reversible causes. Myocardial fibrosis (MF) is not only the hallmark of cardiomyopathy, but also a substrate for sudden cardiac death, ventricular tachyarrhythmia and heart failure. Procollagen carboxyl-terminal telopeptide (PICP) was found to be a marker of MF. The relationship between PICP and cardiac abnormalities in stroke survivors is unknown. We recently showed that MF in stroke survivors can be treated by spironolactone and amiloride in a randomised placebo-controlled cross-over study with reduction in PICP levels and QTc [1]

Anomalous Soft Photons in Hadron Production

Anomalous soft photons in excess of what is expected from electromagnetic bremsstrahlung have been observed in association with the production of hadrons, mostly mesons, in high-energy (K+)p, (pi+)p, (pi-)p, pp, and (e+)(e-) collisions. We propose a model for the simultaneous production of anomalous soft photons and mesons in quantum field theory, in which the meson production arises from the oscillation of color charge densities of the quarks of the underlying vacuum in the flux tube. As a quark carries both a color charge and an electric charge, the oscillation of the color charge densities will be accompanied by the oscillation of electric charge densities, which will in turn lead to the simultaneous production of soft photons during the meson production process. How the production of these soft photons may explain the anomalous soft photon data will be discussed. Further experimental measurements to test the model will be proposed.Comment: 19 pages, 2 figures, to be published in Physical Review

High p_T Triggered Delta-eta,Delta-phi Correlations over a Broad Range in Delta-eta

The first measurement of pseudorapidity (Delta-eta) and azimuthal angle (Delta-phi) correlations between high transverse momentum charged hadrons (p_T > 2.5 GeV/c) and all associated particles is presented at both short- (small Delta-eta) and long-range (large Delta-eta) over a continuous pseudorapidity acceptance (-4<Delta-eta<2). In these proceedings, the various near- and away-side features of the correlation structure are discussed as a function of centrality in Au+Au collisions measured by PHOBOS at sqrt(s_NN)=200 GeV. In particular, this measurement allows a much more complete determination of the longitudinal extent of the ridge structure, first observed by the STAR collaboration over a limited eta range. In central collisions the ridge persists to at least Delta-eta=4, diminishing in magnitude as collisions become more peripheral until it disappears around Npart=80.Comment: 5 pages, 2 figures, presented at the 20th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions, "Quark Matter 2008", Jaipur, India, February 4-10, 2008. Full author list included and typo corrected in equation

Multidimensional Worldline Instantons

We extend the worldline instanton technique to compute the vacuum pair production rate for spatially inhomogeneous electric background fields, with the spatial inhomogeneity being genuinely two or three dimensional, both for the magnitude and direction of the electric field. Other techniques, such as WKB, have not been applied to such higher dimensional problems. Our method exploits the instanton dominance of the worldline path integral expression for the effective action.Comment: 22 pages, 13 figure

Angularly localized Skyrmions

Quantized Skyrmions with baryon numbers $B=1,2$ and 4 are considered and angularly localized wavefunctions for them are found. By combining a few low angular momentum states, one can construct a quantum state whose spatial density is close to that of the classical Skyrmion, and has the same symmetries. For the B=1 case we find the best localized wavefunction among linear combinations of $j=1/2$ and $j=3/2$ angular momentum states. For B=2, we find that the $j=1$ ground state has toroidal symmetry and a somewhat reduced localization compared to the classical solution. For B=4, where the classical Skyrmion has cubic symmetry, we construct cubically symmetric quantum states by combining the $j=0$ ground state with the lowest rotationally excited $j=4$ state. We use the rational map approximation to compare the classical and quantum baryon densities in the B=2 and B=4 cases.Comment: 22 page

Nanoindentation-induced deformation of Ge

The deformation mechanisms of crystalline (100) Ge were studied using nanoindentation, cross sectional transmission electron microscopy (XTEM) and Raman microspectroscopy. For a wide range of indentation conditions using both spherical and pointed indenters, multiple discontinuities were found in the force–displacement curves on loading, but no discontinuities were found on unloading. Raman microspectroscopy, measured from samples which had plastically deformed on loading, showed a spectrum shift from that in pristine Ge, suggesting only residual strain. No evidence (such as extra Raman bands) was found to suggest that any pressure-induced phase transformations had occurred, despite the fact that the material had undergone severe plastic deformation.Selected area diffraction pattern studies of the mechanically damaged regions also confirmed the absence of additional phases. Moreover, XTEM showed that, at low loads, plastic deformation occurs by twinning and dislocation motion. This indicates that the hardness of Gemeasured by indentation is not primarily dominated by phase transformation, rather by the nucleation and propagation of twin bands and/or dislocations

The perception of lexical tone contrasts in Cantonese children with and without Specific Language Impairment (SLI)

Purpose: This study examined the perception of fundamental frequency (f0) patterns by Cantonese children with and without specific language impairment (SLI). Method: Participants were 14 five-year-old children with SLI, and 14 age-matched (AM) and 13 four-year-old vocabulary-matched (VM) controls. The children identified a word from familiar word pairs that illustrated the 8 minimally contrastive pairs of the 6 lexical tones. They discriminated the f0 patterns within contrastive tonal pairs in speech and nonspeech stimuli. Results: In tone identification, the SLI group performed worse than the AM group but not the VM group. In tone discrimination, the SLI group did worse than the AM group on 2 contrasts and showed a nonsignificant trend of poorer performance on all contrasts combined. The VM group generally did worse than the AM group. There were no group differences in discrimination performance between speech and nonspeech stimuli. No correlation was found between identification and discrimination performance. Only the normal controls showed a moderate correlation between vocabulary scores and performance in the 2 perception tasks. Conclusion: The SLI group's poor tone identification cannot be accounted for by vocabulary knowledge alone. The group's tone discrimination performance suggests that some children with SLI have a deficit in f0 processing. © American Speech-Language-Hearing Association.postprin

Fully nonlinear excitations of non-Abelian plasma

We investigate fully nonlinear, non-Abelian excitations of quark-antiquark plasma, using relativistic fluid theory in cold plasma approximation. There are mainly three important nonlinearities, coming from various sources such as non-Abelian interactions of Yang-Mills (YM) fields, Wong's color dynamics and plasma nonlinearity, in our model. By neglecting nonlinearities due to plasma and color dynamics we get back the earlier results of Blaizot {\it et. al.}, Phys. Rev. Lett. 72, 3317 (1994). Similarly, by neglecting YM fields nonlinearity and plasma nonlinearity, it reduces to the model of Gupta {\it et. al.}, Phys. Lett. B498, 223 (2005). Thus we have the most general non-Abelian mode of quark-gluon plasma (QGP). Further, our model resembles the problem of propagation of laser beam through relativistic plasma, Physica 9D, 96 (1983). in the absence of all non-Abelian interactions.Comment: 8 pages, 2 figures, articl