1,111 research outputs found

    Random Lie-point symmetries of stochastic differential equations

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    We study the invariance of stochastic differential equations under random diffeomorphisms, and establish the determining equations for random Lie-point symmetries of stochastic differential equations, both in Ito and in Stratonovich form. We also discuss relations with previous results in the literature.Comment: In new version (November 2017) we have added an important ERRATUM. Due to a trivial mistake in a formula, several examples should be revised; more relevant, the qualitatove results of Section VIII turn out to be wrong, as discussed in the erratum. See also arXiv:1711.0199

    Sulle fonti dell' Assedio di Malta di Antonio Achelis

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    DELAMINAZIONE INTERLAMINARE DI COMPOSITI CFRP AL VARIARE DELLE CONDIZIONI DI CURA DELLA MATRICE

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    In questo lavoro si è condotto uno studio sperimentale del comportamento a delaminazione interlaminare in Modo I di laminati compositi unidirezionali in fibra di carbonio e matrice epossidica (CFRP), al variare delle condizioni di cura della matrice. Tutti i sistemi analizzati hanno utilizzato lo stesso tessuto e lo stesso monomero epossidico DGEBA. Variando il processo di cura (cura termica o mediante radiazioni), gli agenti di cura (ammine o anidridi per i sistemi curati termicamente), e l’impiego di additivi tenacizzanti (es. il PES per i sistemi irradiati), è stato possibile controllare e modificare sia il grado di adesione fibra/matrice, che il grado di fragilità della matrice (monitorato attraverso il Fattore Critico di Intensificazione degli Sforzi KIC). Il lavoro quindi propone una analisi critica dei meccanismi di resistenza alla delaminazione controllati dalla tenacità della matrice e dalla resistenza dell’interfaccia fibra-matrice, mediante la determinazione delle Curve di Resistenza e dei valori di GIC di Innesco e di Propagazione ottenuti per i diversi sistemi presi in esame

    Επιδράσεις του Ariosto στον Ερωτόκριτο. Ο Tasso άγνωστος στον Κορνάρο

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    Water diffusion and swelling stresses in highly crosslinked epoxy matrices

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    The present work investigates the swelling induced stresses arising in two epoxy systems during water uptake. The analysed systems are two epoxy resin based on DGEBA monomer and DGEBF monomer respectively, both fully cured by DDS amine. The systems achieve different cross-link density degrees, and are characterised by high glass transition temperatures ranging between 200 and 230 °C. Both epoxies have been conditioned in deionized water baths at two different temperatures (50 °C and 80 °C). A desorption process at room temperature in a dry airborne environment was performed after saturation. Dynamic Mechanical Thermal Analysis, carried out at the various stages of hydrothermal conditioning, has allowed to characterise the modifications occurring in the network structures during aging. Photoelastic Stress Analysis is adopted to monitor the evolution of stresses on rectangular beam samples during absorption and desorption of water. Correlation of water uptake, dynamic mechanical behaviour and transitory stress fields, has allowed to make some assumptions about the influence of the epoxy network on the swelling behaviour

    Gastric cancer is the leading cause of death in Italian adult patients with common variable immunodeficiency

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    An increased prevalence of malignant lymphoma and of gastric cancer has been observed in large cohorts of patients with common variable immunodeficiency (CVID), the most frequently symptomatic primary immunodeficiency. Surveillance strategies for cancers in CVID should be defined based on epidemiological data. Risks and mortality for cancers among 455 Italian patients with CVID were compared to cancer incidence data from the Italian Cancer Registry database. CVID patients showed an increased cancer incidence for all sites combined (Obs = 133, SIR = 2.4; 95%CI = 1.7\u20133.5), due to an excess of non-Hodgkin lymphoma (Obs = 33, SIR = 14.3; 95%CI = 8.4\u201322.6) and of gastric cancer (Obs = 25; SIR = 6.4; 95%CI = 3.2\u201312.5). CVID patients with gastric cancer and lymphoma had a worse survival in comparison to cancer-free CVID (HR: 4.8, 95%CI: 4.2\u201344.4 and HR: 4.2, 95%CI: 2.8\u201344.4). Similar to what observed in other series, CVID-associated lymphomas were more likely to be of B cell origin and often occurred at extra-nodal sites. We collected the largest case-series of gastric cancers in CVID subjects. In contrast to other reports, gastric cancer was the leading cause of death in CVID. Standardized mortality ratio indicated a 10.1-fold excess mortality among CVID patients with gastric cancer. CVID developed gastric cancer 15 years earlier than the normative population, but they had a similar overall survival. Only CVID diagnosed at early stage gastric cancer survived >24 months. Stomach histology from upper endoscopy performed before cancer onset showed areas of atrophic gastritis, intestinal metaplasia or dysplasia. CVID patients might progress rapidly to an advanced cancer stage as shown by patients developing a III-IV stage gastric cancer within 1 year from an endoscopy without signs of dysplasia. Based on high rate of mortality due to gastric cancer in Italian CVID patients, we hereby suggest a strategy aimed at early diagnosis, based on regular upper endoscopy and on Helicobacter pylori infection treatment, recommending an implementation of national guidelines

    Static hot air and infrared rays roasting are efficient methods for aflatoxin decontamination on hazelnuts

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    Aflatoxins are a group of secondary metabolites produced by members of Aspergillus Section Flavi that are dangerous to humans and animals. Nuts can be potentially contaminated with aflatoxins, often over the legal threshold. Food processes, including roasting, may have different effects on mycotoxins, and high temperatures have proven to be very effective in the reduction of mycotoxins. In this work, two different roasting methods—traditional static hot air roasting and infra-red rays roasting—were applied and compared for the detoxification of hazelnuts from Italy and Turkey. At the temperature of 140 °C for 40 min of exposure, detoxification was effective for both roasting techniques. Residual aflatoxins after infra-red rays treatments were lower compared to static hot air roasting. On Italian hazelnuts, residual aflatoxins were lower than 5%, while for Turkish hazelnuts they were lower than 15% after 40 min of exposure to an infra-red rays roaster. After roasting, the perisperm was detached from the nuts and analyzed for aflatoxin contents. Residual aflatoxins in the perisperm ranged from 80% up to 100%. After roasting, the lipid profile and the nutritional quality of hazelnuts were not affected. Fatty acid methyl esters analyses showed a similar composition for Italian and Turkish hazelnuts
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