832 research outputs found

    The role of initial conditions in the ageing of the long-range spherical model

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    The kinetics of the long-range spherical model evolving from various initial states is studied. In particular, the large-time auto-correlation and -response functions are obtained, for classes of long-range correlated initial states, and for magnetized initial states. The ageing exponents can depend on certain qualitative features of initial states. We explicitly find the conditions for the system to cross over from ageing classes that depend on initial conditions to those that do not.Comment: 15 pages; corrected some typo

    Dynamic heterogeneities in critical coarsening: Exact results for correlation and response fluctuations in finite-sized spherical models

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    We study dynamic heterogeneities in the out-of-equilibrium coarsening dynamics of the spherical ferromagnet after a quench from infinite temperature to its critical point. A standard way of probing such heterogeneities is by monitoring the fluctuations of correlation and susceptibility, coarse-grained over mesoscopic regions. We discuss how to define fluctuating coarse-grained correlations (C) and susceptibilities (Chi) in models where no quenched disorder is present. Our focus for the spherical model is on coarse-graining over the whole volume of NN spins, which requires accounting for N^{-1/2} non-Gaussian fluctuations of the spin. The latter are treated as a perturbation about the leading order Gaussian statistics. We obtain exact results for these quantities, which enable us to characterise the joint distribution of C and Chi fluctuations. We find that this distribution is qualitatively different, even for equilibrium above criticality, from the spin-glass scenario where C and Chi fluctuations are linked in a manner akin to the fluctuation-dissipation relation between the average C and Chi. Our results show that coarsening at criticality is clearly heterogeneous for d>4 and suggest that, as in other glassy systems, there is a well-defined timescale on which fluctuations across thermal histories are largest. Surprisingly, however, neither this timescale nor the amplitude of the heterogeneities increase with the age of the system, as would be expected from the growing correlation length. For d<4, the strength of the fluctuations varies on a timescale proportional to the age of the system; the corresponding amplitude also grows with age, but does not scale with the correlation volume as might have been expected naively.Comment: 39 pages, 9 figures, version for publication in J. Stat. Mech. Shortened by cutting all technical details in section 6, with minor corrections elsewher

    Coexistence of supersymmetric and supersymmetry-breaking states in spherical spin-glasses

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    The structure of states of the perturbed p-spin spherical spin-glass is analyzed. At low enough free energy metastable states have a supersymmetric structure, while at higher free energies the supersymmetry is broken. The transition between the supersymmetric and the supersymmetry-breaking phase is triggered by a change in the stability of states

    Time trend occurrence of duodenal intraepithelial lymphocytosis and celiac disease in an open access endoscopic population

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    Background: Duodenal intraepithelial lymphocytosis (DIL) is a histological finding characterized by the increase of intraepithelial CD3T-lymphocytes over the normal value without villous atrophy, mostly associated to coeliac disease (CD), Helicobacter pylori (Hp) gastritis and autoimmune diseases. Objective: To assess the occurrence of DIL, CD and Hp gastritis in an endoscopic population over a 13 year period. Methods: From 2003 to 2015 we included adult patients who consecutively underwent oesophago-gastro-duodenoscopy (OGD) with duodenal biopsies assessing the overall and annual occurrence of DIL and CD and the prevalence of Hp gastritis. Results: 160 (2.3%) patients with DIL and 275 (3.9%) with CD were detected among 7001 patients. CD occurrence was higher from 2003 to 2011, while since 2012 DIL occurrence gradually increased significantly compared to CD (p = 0.03). DIL patients were more frequently female (p = 0.0006) and underwent OGD more frequently for dyspepsia (p = 0.002) and for indications not related to gastrointestinal symptoms than CD patients (p = 0.0003). Hp gastritis occurred similarly in CD and DIL patients but the latter had higher frequency of atrophic body gastritis (p = 0.005). Conclusions: DIL is a condition increasing in the general endoscopic population mainly diagnosed by chance. Concomitant gastric histological evaluation is able in one third of DIL patients to identify associated possible causes of DIL, such as Hp and atrophic gastritis

    Environmental Risk Assessment in the Tuscany Region: a Proposal

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    Practice parameters for the treatment of colonic diverticular disease: Italian Society of Colon and Rectal Surgery (SICCR) guidelines

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    The mission of the Italian Society of Colorectal Surgery (SICCR) is to optimize patient care. Providing evidence-based practice guidelines is therefore of key importance. About the present report it concernes the SICCR practice guidelines for the diagnosis and treatment of diverticular disease of the colon. The guidelines are not intended to define the sole standard of care but to provide evidence-based recommendations regarding the available therapeutic options

    Hypergastrinemia and enterochromaffin-like cell hyperplasia.

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    The enterochromaffin-like (ECL) cells, the most frequent endocrine cells of the oxyntic mucosa of the stomach, are under the trophic stimulus of gastrin. These cells undergo a hyperplastic increase in variety of hypergastrinemic diseases. The most widely accepted nomenclature for the description of hyperplastic proliferation has been retrospectively arranged in a sequence presumed to reflect a temporal evolution of the proliferative process. A comparative, prospective study aimed to verify, in human hypergastrinemic diseases such as atrophic body gastritis (ABG), Zollinger-Ellison syndrome (ZES) and antral gastrin cell hyperfunction (AGCH), the effect of exposure of ECL cells to different pattern of gastrin hypersecretion, is lacking. To this purpose, we studied a series of consecutive patients with ABG, ZES and AGCH at the time of first diagnosis. Material and Methods: The patients included in this study (124 ABG, 18 ZES and 10 AGCH) were selected on the basis of two previously performed screening studies aimed to diagnose these diseases. All patients at the time of diagnosis underwent gastroscopy, with multiple biopsies of the gastric body mucosa for the evaluation of qualitative pattern of ECL cells hyperplasia, and basal fasting gastrin determination. A sample of hypergastrinemic patients from each group was further investigated by meal-stimulation of gastrin secretion and quantitative morphometry for CgA positive gastric body endocrine cells. Results: AGCH patients showed only the normal or simple hyperplasia pattern. In the ZES group, simple and linear grades accounted for 38.4 percent and 46.1 percent, respectively. MEN-I patients showed only these two patterns. The majority of ABG patients showed the presence of micronodular pattern (59.7 percent). A correlation analysis between fasting gastrin levels and grade of hyperplasia (r = 0.5580, p < 0.0001), indicates that the greater the gastrin levels, the higher is the degree of severity of ECL hyperplasia pattern. In conclusion, our data support the role of gastrin as the selective contributor to the progression of ECL cell hyperplasia in humans

    MWNT Surface Self-Assembling in Fire Retardant Polyethylene-Carbon nanotubes nanocomposites

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    Multiwall carbon nanotubes (MWNT) were melt blended at different concentration with linear low density polyethylene (LLDPE). The nanotubes impart the fire-retardant characteristics to the polymer by formation of a thin protective film of MWNT/carbon char generated on the surface of the nanocomposites. The film formation mechanism is discussed

    Iron deficiency anemia caused by nonspecific (idiopathic) small bowel ulceration: an uncommon presentation of an uncommon disease.

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    Ulcers of the small bowel are rare, and in most cases are due to infections, inflammatory bowel diseases, malignancies or drugs. When none of these causes is recognized, they are classified as 'nonspecific' or idiopathic. Such lesions are uncommon, and in most cases present with occlusion. A case of a middle-aged woman with iron deficiency anemia due to occult bleeding, with negative gastroscopy and colonoscopy is presented. The diagnosis of a small bowel pathology resembling Crohn's disease was made by small bowel follow through and small intestine contrast ultrasonography. An ileal ulcer was identified at surgery, and after resection the patient experienced a stable recovery from the anemia without ulcer recurrence. Neither histology nor clinical or biochemical features suggested the diagnosis of an inflammatory bowel disease. Other possible causes were unlikely and the lesion was therefore diagnosed as idiopathic. This report also focuses on the need and the modality to investigate the small bowel in iron deficiency anemia patients

    Progression to Overt Nephropathy in Type 2 Diabetes: the Casale Montferrato Study

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