409 research outputs found

    Velocity Distribution of Topological Defects in Phase-Ordering Systems

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    The distribution of interface (domain-wall) velocities v{\bf v} in a phase-ordering system is considered. Heuristic scaling arguments based on the disappearance of small domains lead to a power-law tail, Pv(v)vpP_v(v) \sim v^{-p} for large v, in the distribution of vvv \equiv |{\bf v}|. The exponent p is given by p=2+d/(z1)p = 2+d/(z-1), where d is the space dimension and 1/z is the growth exponent, i.e. z=2 for nonconserved (model A) dynamics and z=3 for the conserved case (model B). The nonconserved result is exemplified by an approximate calculation of the full distribution using a gaussian closure scheme. The heuristic arguments are readily generalized to conserved case (model B). The nonconserved result is exemplified by an approximate calculation of the full distribution using a gaussian closure scheme. The heuristic arguments are readily generalized to systems described by a vector order parameter.Comment: 5 pages, Revtex, no figures, minor revisions and updates, to appear in Physical Review E (May 1, 1997

    Non-equilibrium Condensation Process in a Holographic Superconductor

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    We study the non-equilibrium condensation process in a holographic superconductor. When the temperature T is smaller than a critical temperature T_c, there are two black hole solutions, the Reissner-Nordstrom-AdS black hole and a black hole with a scalar hair. In the boundary theory, they can be regarded as the supercooled normal phase and the superconducting phase, respectively. We consider perturbations on supercooled Reissner-Nordstrom-AdS black holes and study their non-linear time evolution to know about physical phenomena associated with rapidly-cooled superconductors. We find that, for T<T_c, the initial perturbations grow exponentially and, eventually, spacetimes approach the hairy black holes. We also clarify how the relaxation process from a far-from-equilibrium state proceeds in the boundary theory by observing the time dependence of the superconducting order parameter. Finally, we study the time evolution of event and apparent horizons and discuss their correspondence with the entropy of the boundary theory. Our result gives a first step toward the holographic understanding of the non-equilibrium process in superconductors.Comment: 20 pages, 7 figure

    Resezioni polmonari limitate “intenzionali” versus lobectomie nel trattamento dei tumori polmonari periferici non microcitomi allo stadio IA

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    Scopo del presente studio è valutare, attraverso l’analisi retrospettiva della nostra casistica e la revisione della letteratura, se le resezioni polmonari limitate siano equivalenti alla lobectomia nel trattamento dei tumori polmonari non microcitomi (NSCLC) periferici allo stadio IA (T1N0M0), in termini di radicalità oncologica, sopravvivenza e tasso di recidive locali, regionali e sistemiche.Viene inoltre preso in considerazione l’impatto delle resezioni limitate, rispetto alle resezioni lobari, sulla funzionalità polmonare postoperatoria. Pazienti e metodi. Abbiamo analizzato una serie consecutiva di 36 pazienti, 28 uomini e 8 donne, di età compresa fra 61 e 81 anni (media 73 anni), sottoposti ad intervento chirurgico, nel periodo compreso fra gennaio 2000 e dicembre 2003, per NSCLC periferici T1N0M0; sono state effettuate 11 resezioni limitate e 25 lobectomie. Sono state analizzate comparativamente sopravvivenza e recidive (follow-up 3-5 anni), nonché le prove di funzionalità respiratoria ad un anno dall’intervento. Risultati. La sopravvivenza a 3 e 5 anni è stata pari all’88% ed all’82% nel gruppo dei pazienti sottoposti a resezioni limitate, al 93% e all’88% nel gruppo dei pazienti sottoposti a lobectomia. Si è verificata una recidiva locale (9%) nel primo gruppo, una (4%) nel secondo. Ad un anno dall’intervento si sono osservati un moderato decremento del volume espiratorio forzato in 1 secondo (FEV1) e della capacità di diffusione per monossido di carbonio (DLCO) nei pazienti sottoposti a resezione lobare, e un sostanziale mantenimento dei parametri funzionali preoperatori, eccezion fatta per la DLCO, nei pazienti sottoposti a resezione limitata. Conclusioni. La nostra circoscritta esperienza, in accordo con le tendenze attuali della letteratura, indica che l’intervento di resezione polmonare limitata, in pazienti selezionati, con NSCLC periferici allo stadio IA, rappresenta una valida alternativa alla lobectomia in termini di sopravvivenza e tasso di recidiva, determinando altresì un minor decremento della funzionalità polmonare postoperatoria. La segmentectomia può essere dunque considerata, in tali casi, procedura chirurgica di scelta, anche in pazienti in grado di tollerare una resezione maggior

    Scaling Model of Annihilation-Diffusion Kinetics for Charged Particles with Long-Range Interactions

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    We propose the general scaling model for the diffusio n-annihilation reaction A++AA_{+} + A_{-} \longrightarrow \emptyset with long-range power-law i nteractions. The presented scaling arguments lead to the finding of three different regimes, dep ending on the space dimensionality d and the long-range force power e xponent n. The obtained kinetic phase diagram agrees well with existing simulation data and approximate theoretical results.Comment: RevTEX, 7 pages, no figures, accepted to Physical Review

    PROTECTIVE EFFECTS OF ANTHOCYANINS FROM BLACKBERRY IN A RAT MODEL OF ACUTE LUNG INFLAMMATION.

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    Anthocyanins are a group of naturally occuring phenolic compounds related to the coloring of plants, flowers and fruits. These pigments are important as quality indicators, as chemotaxonomic markers and for their antioxidant activities. Here, we have investigated the therapeutic efficacy of anthocyanins contained in blackberry extract (cyanidin-3-O-glucoside represents about 80% of the total anthocyanin contents) in an experimental model of lung inflammation induced by carrageenan in rats. Injection of carrageenan into the pleural cavity elicited an acute inflammatory response characterized by fluid accumulation which contained a large number of neutrophils as well as an infiltration of polymorphonuclear leukocytes in lung tissues and subsequent lipid peroxidation, and increased production of nitrite/nitrate (NOx) and prostaglandin E2 (PGE2). All parameters of inflammation were attenuated in a dose-dependent manner by anthocyanins (10, 30 mg kg-1 30 min before carrageenan). Furthermore, carrageenan induced an upregulation of the adhesion molecule ICAM-1, nitrotyrosine and poly (ADP-ribose) synthetase (PARS) as determined by immunohistochemical analysis of lung tissues. The degree of staining was lowered by anthocyanins treatment. Thus, the anthocyanins contained in the blackberry extract exert multiple protective effects in carrageenan-induced pleurisy

    Self-Consistent Model of Annihilation-Diffusion Reaction with Long-Range Interactions

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    We introduce coarse-grained hydrodynamic equations of motion for diffusion-annihilation system with a power-law long-range interaction. By taking into account fluctuations of the conserved order parameter - charge density - we derive an analytically solvable approximation for the nonconserved order parameter - total particle density. Asymptotic solutions are obtained for the case of random Gaussian initial conditions and for system dimensionality d2d \geq 2. Large-t, intermediate-t and small-t asymptotics were calculated and compared with existing scaling theories, exact results and simulation data.Comment: 22 pages, RevTEX, 1 PostScript figur

    Growth Laws for Phase Ordering

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    We determine the characteristic length scale, L(t)L(t), in phase ordering kinetics for both scalar and vector fields, with either short- or long-range interactions, and with or without conservation laws. We obtain L(t)L(t) consistently by comparing the global rate of energy change to the energy dissipation from the local evolution of the order parameter. We derive growth laws for O(n) models, and our results can be applied to other systems with similar defect structures.Comment: 12 pages, LaTeX, second tr

    Estimation of vortex density after superconducting film quench

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    This paper addresses the problem of vortex formation during a rapid quench in a superconducting film. It builds on previous work showing that in a local gauge theory there are two distinct mechanisms of defect formation, based on fluctuations of the scalar and gauge fields, respectively. We show how vortex formation in a thin film differs from the fully two-dimensional case, on which most theoretical studies have focused. We discuss ways of testing theoretical predictions in superconductor experiments and analyse the results of recent experiments in this light.Comment: 7 pages, no figure

    The Use of Biofluid Markers to Evaluate the Consequences of Sport-Related Subconcussive Head Impact Exposure : A Scoping Review

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    Funding Information: This review was supported by the University of Stirling (no grant number applies). L.W. also received support as part of Framework 7 programme of the European Union (CENTER-TBI, Grant number: 602150–2). S.M. received research support from the Italian Ministry of Health (GR-2013–02354960).Peer reviewe

    Machine learning to improve interpretability of clinical, radiological and panel-based genomic data of glioma grade 4 patients undergoing surgical resection

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    Background: Glioma grade 4 (GG4) tumors, including astrocytoma IDH-mutant grade 4 and the astrocytoma IDH wt are the most common and aggressive primary tumors of the central nervous system. Surgery followed by Stupp protocol still remains the first-line treatment in GG4 tumors. Although Stupp combination can prolong survival, prognosis of treated adult patients with GG4 still remains unfavorable. The introduction of innovative multi-parametric prognostic models may allow refinement of prognosis of these patients. Here, Machine Learning (ML) was applied to investigate the contribution in predicting overall survival (OS) of different available data (e.g. clinical data, radiological data, or panel-based sequencing data such as presence of somatic mutations and amplification) in a mono-institutional GG4 cohort. Methods: By next-generation sequencing, using a panel of 523 genes, we performed analysis of copy number variations and of types and distribution of nonsynonymous mutations in 102 cases including 39 carmustine wafer (CW) treated cases. We also calculated tumor mutational burden (TMB). ML was applied using eXtreme Gradient Boosting for survival (XGBoost-Surv) to integrate clinical and radiological information with genomic data. Results: By ML modeling (concordance (c)- index = 0.682 for the best model), the role of predicting OS of radiological parameters including extent of resection, preoperative volume and residual volume was confirmed. An association between CW application and longer OS was also showed. Regarding gene mutations, a role in predicting OS was defined for mutations of BRAF and of other genes involved in the PI3K-AKT-mTOR signaling pathway. Moreover, an association between high TMB and shorter OS was suggested. Consistently, when a cutoff of 1.7 mutations/megabase was applied, cases with higher TMB showed significantly shorter OS than cases with lower TMB. Conclusions: The contribution of tumor volumetric data, somatic gene mutations and TBM in predicting OS of GG4 patients was defined by ML modeling
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