11,524 research outputs found

    Numerical study on Schramm-Loewner Evolution in nonminimal conformal field theories

    Get PDF
    The Schramm-Loewner evolution (SLE) is a powerful tool to describe fractal interfaces in 2D critical statistical systems. Yet the application of SLE is well established for statistical systems described by quantum field theories satisfying only conformal invariance, the so called minimal conformal field theories (CFTs). We consider interfaces in Z(N) spin models at their self-dual critical point for N=4 and N=5. These lattice models are described in the continuum limit by non-minimal CFTs where the role of a Z_N symmetry, in addition to the conformal one, should be taken into account. We provide numerical results on the fractal dimension of the interfaces which are SLE candidates for non-minimal CFTs. Our results are in excellent agreement with some recent theoretical predictions.Comment: 4 pages, 2 figures, v2: typos corrected, published versio

    Ripening-induced changes in microbial groups of artisanal Sicilian goats' milk cheese.

    Get PDF
    Changes in the microbial flora of "Caprino dei Nebrodi", a raw goat's milk cheese produced in Sicily, were studied during ripening. From 2 batches of cheese, 4 samples were taken at day 0, 2, 15, and 30 of ripening. Also, samples of curd and milk used in the manufacturing process were analyzed. By the end of the ripening process (day 30), high log10 cfu/g were found for Lactobacilli (7.20), Lattococci (7.10), and Enterococci (7.00), whereas counts of Enterobacteriaceae (3.91), Escherichia coli (3.30), and Staphylococcus (3.89) were found to be lower. The study provides useful information on the microbiological properties of "Caprino dei Nebrodi" cheese, and the results obtained suggest that in order to increase the quality of this artisanal product, it is necessary to improve the sanitary conditions of milking and cheese-making. The study was intended as a preliminary step towards the isolation and identification of bacterial species found in this type of goat's cheese

    Gravitational diffraction radiation

    Get PDF
    We show that if the visible universe is a membrane embedded in a higher-dimensional space, particles in uniform motion radiate gravitational waves because of spacetime lumpiness. This phenomenon is analogous to the electromagnetic diffraction radiation of a charge moving near to a metallic grating. In the gravitational case, the role of the metallic grating is played by the inhomogeneities of the extra-dimensional space, such as a hidden brane. We derive a general formula for gravitational diffraction radiation and apply it to a higher-dimensional scenario with flat compact extra dimensions. Gravitational diffraction radiation may carry away a significant portion of the particle's initial energy. This allows to set stringent limits on the scale of brane perturbations. Physical effects of gravitational diffraction radiation are briefly discussed.Comment: 5 pages, 2 figures, RevTeX4. v2: References added. Version to appear in Phys. Rev.

    Saffron: A multitask neuroprotective agent for retinal degenerative diseases

    Get PDF
    Both age related macular degeneration (AMD) and light induced retinal damage share the common major role played by oxidative stress in the induction/progression of degenerative events. Light damaged (LD) rats have been widely used as a convenient model to gain insight into the mechanisms of degenerative disease, to enucleate relevant steps and to test neuroprotectants. Among them, saffron has been shown to ameliorate degenerative processes and to regulate many genes and protective pathways. Saffron has been also tested in AMD patients. We extended our analysis to a possible additional effect regulated by saffron and compared in AMD patients a pure antioxidant treatment (Lutein/zeaxanthin) with saffron treatment. Methods: Animal model. Sprague-Dawley (SD) adult rats, raised at 5 lux, were exposed to 1000 lux for 24 h and then either immediately sacrificed or placed back at 5 lux for 7 days recovery period. A group of animals was treated with saffron. We performed in the animal model: (1) SDS-PAGE analysis; (2) Western Blotting (3) Enzyme activity assay (4) Immunolabelling; in AMD patients: a longitudinal open-label study 29 (+/- 5) months in two groups of patients: lutein/zeaxanthin (19) and saffron (23) treated. Visual function was tested every 8 months by ERG recordings in addition to clinical examination. Results: Enzymatic activity of MMP-3 is reduced in LD saffron treated retinas and is comparable to control as it is MMP-3 expression. LD treated retinas do not present "rosettes" and microglia activation and migration is highly reduced. Visual function remains stable in saffron treated AMD patients while deteriorates in the lutein/zeaxanthin group. Conclusion: Our results provide evidence of an additional way of action of saffron treatment confirming the complex nature of neuroprotective activities of its chemical components. Accordingly, long term follow-up in AMD patients reveals an added value of saffron supplementation treatment compared to classical antioxidant protocol

    High density QCD on a Lefschetz thimble?

    Get PDF
    It is sometimes speculated that the sign problem that afflicts many quantum field theories might be reduced or even eliminated by choosing an alternative domain of integration within a complexified extension of the path integral (in the spirit of the stationary phase integration method). In this paper we start to explore this possibility somewhat systematically. A first inspection reveals the presence of many difficulties but - quite surprisingly - most of them have an interesting solution. In particular, it is possible to regularize the lattice theory on a Lefschetz thimble, where the imaginary part of the action is constant and disappears from all observables. This regularization can be justified in terms of symmetries and perturbation theory. Moreover, it is possible to design a Monte Carlo algorithm that samples the configurations in the thimble. This is done by simulating, effectively, a five dimensional system. We describe the algorithm in detail and analyze its expected cost and stability. Unfortunately, the measure term also produces a phase which is not constant and it is currently very expensive to compute. This residual sign problem is expected to be much milder, as the dominant part of the integral is not affected, but we have still no convincing evidence of this. However, the main goal of this paper is to introduce a new approach to the sign problem, that seems to offer much room for improvements. An appealing feature of this approach is its generality. It is illustrated first in the simple case of a scalar field theory with chemical potential, and then extended to the more challenging case of QCD at finite baryonic density.Comment: Misleading footnote 1 corrected: locality deserves better investigations. Formula (31) corrected (we thank Giovanni Eruzzi for this observation). Note different title in journal versio

    Two novel amino acid substitutions in highly conserved regions of prion protein (PrP) and a high frequency of a scrapie protective variant in native Ethiopian goats

    Get PDF
    BackgroundPolymorphisms of the prion protein gene may influence scrapie susceptibility in small ruminants through modified protein conformation. At least 47 amino acid substitutions and 19 silent polymorphisms have been described in goat PRNP reported from several countries. The objective of this study was to investigate PRNP polymorphisms of native Ethiopian goat breeds and compare the results with other goat breeds.ResultsThe analysis of the prion protein gene PRNP in 229 goats belonging to three of the main Ethiopian native goat breeds showed a remarkably high frequency (>34.6%) of p.(Asn146Ser) in these breeds, a variant involved in scrapie resistance in Cyprus. In addition, two novel amino-acid substitutions p.(Gly127Ala) and p.(Thr193Ile), with frequencies ranging from 1.5 to 7.3% were detected. Both amino acids are well conserved in prion proteins (PrP) of most species and these changes have never been reported before in goats worldwide. Residue 127 is within the N-terminal domain of PrP and is probably involved in the recruitment of neural cell adhesion molecules (NCAM). Residue 193 is within the highly conserved string of 4 threonines that plays a role in determining the efficiency of prion protein conversion towards its pathological form.ConclusionTwo novel coding polymorphisms and a high frequency of a scrapie protective variant indicate a high level of genetic diversity in PRNP of Ethiopian goats. This finding increases the interest in exploring PRNP polymorphisms of native goat breeds in areas where cross breeding with foreign goats has rarely occurred

    Ruolo della chirurgia endovascolare nelle rotture aortiche del politraumatizzato con lesioni polidistrettuali di pertinenza chirurgica

    Get PDF
    Nel politraumatizzato con gravi lesioni polidistrettuali di interesse chirurgico il trattamento endovascolare (TEV) della rottura posttraumatica dell’ aorta toracica (RPAT) rappresenta oggi una valida alternativa terapeutica al trattamento chirurgico convenzionale. Nella nostra esperienza (ottobre 2001-novembre 2004) abbiamo osservato 5 casi di RPAT (3 rotture istmiche, 2 rotture aorta toracica discendente) in gravi politraumatizzati, tutti di sesso maschile, di età compresa fra i 23 ed i 42 anni (media 32,4), trattate con successo con TEV. Il Glasgow Coma Score (GCS) era compreso fra 5 e 13. Tutti i pazienti sono stati sottoposti, dopo adeguata stabilizzazione del quadro clinico-emodinamico, ad angio-TC total body al fine di valutare la lesione aortica ed identificare le altre lesioni associate. In 4 casi erano coinvolti più distretti corporei di pertinenza chirurgica (3 casi: trauma osseo, addominale e neurochirurgico; 1 caso: trauma osseo, addominale, neurochirurgico e toracico). Il TEV è stato eseguito sempre in sala operatoria previa arteriografia digitale. La durata media della procedura angio-radiologica è stata di 105 minuti (range 80 - 125). Non si è verificata nessuna complicanza né immediata né a distanza (follow-up = medio 24 mesi; range 12-36). In conclusione il TEV delle RPAT offre in pazienti ‘critici’ una valida opzione terapeutica alla chirurgia tradizionale in grado di stabilizzare il quadro clinico e trattare successivamente ‘in sicurezza’ le altre gravi lesioni chirurgiche associate

    Redefining the histopathologic profile of acute aortic syndromes: Clinical and prognostic implications

    Get PDF
    Objectives: The study objectives were to describe the aortic histopathologic substrates in patients with type A surgically treated acute aortic syndromes, to provide clinico-pathological correlations, and to identify the possible prognostic role of histology. Methods: We assessed the aortic wall degenerative or inflammatory alterations of 158 patients according to the histopathologic consensus documents. Moreover, we correlated these histologic patterns with the patients' clinical data and long-term follow-up for mortality, major aorta-related events, and nonaorta-related events (including cardiovascular ones). Results: We identified 2 histopathologic patterns: 122 patients (77%) with degenerative alterations and 36 patients (23%) with mixed degenerative-atherosclerotic lesions. Patients with mixed alterations were older (mean 69.6 \ub1 8.7 years vs 62.2 \ub1 12.4 years, P = .001) and more hypercholesterolemic (33.3% vs 13.9%, P = .017). The degenerative subgroup showed more intralamellar-mucoid extracellular matrix accumulation (86% vs 66.7%, P = .017) and a lower prevalence of translamellar collagen increase (9.8% vs 50%, P < .001). Patients with mixed degenerative-atherosclerotic abnormalities more frequently had long-term nonaorta-related events compared with those with degenerative abnormalities alone (P = .046); no differences were found between the groups with respect to mortality, major aorta-related events, and cardiovascular nonaorta-related events. Conclusions: Although degenerative lesions of the medial layer were present in all specimens, substantial atherosclerosis coexisted in approximately one quarter of cases. Patients with mixed degenerative-atherosclerotic abnormalities had a coherent clinical risk profile, a clinical presentation frequently mimicking acute coronary syndrome, and a higher incidence of nonaorta-related events during follow-up. Histopathologic characterization may improve the long-term prognostic stratification of patients after surgical treatment. \ua9 2018 The American Association for Thoracic Surger

    Study of high-pT charged particle suppression in PbPb compared to pp collisions at √sNN = 2.76 TeV

    Get PDF
    The transverse momentum spectra of charged particles have been measured in pp and PbPb collisions at √sNN=276 TeV by the CMS experiment at the LHC. In the transverse momentum range p_T = 5–10 GeV/c, the charged particle yield in the most central PbPb collisions is suppressed by up to a factor of 7 compared to the pp yield scaled by the number of incoherent nucleon–nucleon collisions. At higher p_T, this suppression is significantly reduced, approaching roughly a factor of 2 for particles with p_T in the range p_T=40–100 GeV/c

    Jet production rates in association with W and Z bosons in pp collisions at √s = 7 TeV

    Get PDF
    Measurements of jet production rates in association with W and Z bosons for jet transverse momenta above 30 GeV are reported, using a sample of proton-proton collision events recorded by CMS at √s = 7TeV, corresponding to an integrated luminosity of 36 pb^(-1). The study includes the measurement of the normalized inclusive rates of jets σ(V+ ≥n jets)/σ(V), where V represents either a W or a Z. In addition, the ratio of W to Z cross sections and the W charge asymmetry as a function of the number of associated jets are measured. A test of scaling at √s = 7TeV is also presented. The measurements provide a stringent test of perturbative-QCD calculations and are sensitive to the possible presence of new physics. The results are in agreement with the predictions of a simulation that uses explicit matrix element calculations for nal states with jets
    corecore