338 research outputs found

    Probing dark matter with polarimetry techniques

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    In this work, we propose polarimetry experiments to search for low-mass (sub-eV) bosonic field dark matter, including axions and axion-like particles. We show that a polarimetry configuration consisting of a thick birefringent solid inside a Fabry-P\'erot cavity is exceptionally sensitive to scalar field dark matter, which may cause oscillatory variations in the solid's thickness and refractive index. In addition, we show that a reconfiguration of this polarimetry experiment, in which two quarter-wave plates are placed inside the Fabry-P\'erot cavity instead of a thick birefringent solid, is very sensitive to axion-like particles. We investigate the possibility of using cross-correlation of twin polarimeters to increase the sensitivity of the experiment, which in turn could allow us to explore unexplored parts of the parameter space and potentially detect a signal in either dark matter scenario

    A Systematic Review on Natural Antioxidant Properties of Resveratrol

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    Polyphenols, including anthocyanins, flavonoids and stilbenes, which constitute one of the most abundant and ubiquitous groups of plant metabolites, are an integral part of the human diet. Resveratrol (3,5,4'-trihydroxystilbene), a naturally occurring polyphenol produced by some plants as a self-defence agent, has an antifungal activity. Resveratrol has been found in some plants (such as grapevine, pine and peanuts) and is considered to have beneficial effects also on human health. The number of studies on resveratrol greatly increased in PubMed database since 1997, after the anticancer effect of this molecule was first reported. The interest in resveratrol in grape was originally sparked by epidemiological studies indicating an inverse relationship between long-standing moderate consumption of red wine and the risk of coronary heart disease; this effect has been ascribed to resveratrol, which possesses diverse biochemical and physiological properties, including antiplatelet and anti-inflammatory proprieties, and provides a wide range of health benefits ranging from chemoprevention to cardioprotection. Recently, resveratrol has been described as an anti-aging compound. The consumption of resveratrol (red wine) together with a Mediterranean diet or a fast-food meal ("McDonald'sMeal") had a positive impact on oxidized (ox-) LDL and on the expression of oxidative and inflammatory genes. Therefore, this review summarized the most important scientific data about healing and preventive potential of resveratrol, acting as cardioprotective, neuroprotective, chemopreventive and antioxidant agent

    QR code and the wine sector: What contents? an exploratory research study on the wine industry

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    This paper presents an explorative analysis of the contents shared through QR codes as a tool of proximity marketing. The aim of the research is to identify the most common links shared through the QR code technology, in order to investigate the use of this tool from a marketing point of view. Moreover, the research explores the main aspects of the communications related to the contents shared through QR codes. Specifically, the authors focus on hedonic aspects and functional ones. Finally, the research aims at identifying preliminary best practices in the use of QR code technology. Due to the widespread use of this tool in the sector, the research focuses on the wine industry, as one of the most involved with QR code practices. The study adopts a qualitative approach based on a content analysis of 91 wine labels. Considering the importance of this integrated communication, the purpose of this explorative analysis is to deduce implications that enable managers to master the use of this tool, exploiting all its potential

    Advancement flap in the management of chronic anal fissure: A prospective study

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    Lateral internal sphincterotomy is the surgical treatment of choice of chronic anal fissure after failure of conservative measures. Several randomized trials identified an overall risk of incontinence of 10 % mostly for flatus. Fissurectomy is the most commonly used procedure to preserve the integrity of the anal sphincters. However, a possible complication is keyhole defect that may lead to faecal soiling. In this study, chronic anal fissure (CAF) was treated by fissurectomy and anal advancement flap to preserve the anatomo-functional integrity of sphincters and to reduce healing time and the risk of anal stenosis. In patients with hypertonia, surgical treatment was combined with chemical sphincterotomy by injection of botulinum toxin to enhance tissue perfusion. Forty eight patients with CAF underwent fissurectomy and anal advancement flap. In 22 subjects with hypertonia of the internal anal sphincter, intrasphincter injection of 30 UI of botulinum toxin at the completion of the surgical operation was used. All patients were followed up to 24 months. Since the first defecation, the intensity and duration of pain were significantly reduced. Two patients had urinary retention, five had infections and three had partial breakdowns. No anal stenosis, keyhole deformity or necrosis flap was recorded. At the 24 months follow-up visit, anal incontinence was similar to those detected preoperatively. Only four recurrences were detected at 18 and 20 months. After medical treatment failure, fissurectomy with advancement flap is a valid sphincter-conserving procedure for treatment of anterior or posterior CAF, regardless of hypertonia of the internal anal sphincter. © 2011 Springer-Verlag

    Conventional and HD-tDCS May (or May Not) Modulate Overt Attentional Orienting: An Integrated Spatio-Temporal Approach and Methodological Reflections.

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    Transcranial Direct Current Stimulation (tDCS) has been employed to modulate visuo-spatial attentional asymmetries, however, further investigation is needed to characterize tDCS-associated variability in more ecological settings. In the present research, we tested the effects of offline, anodal conventional tDCS (Experiment 1) and HD-tDCS (Experiment 2) delivered over the posterior parietal cortex (PPC) and Frontal Eye Field (FEF) of the right hemisphere in healthy participants. Attentional asymmetries were measured by means of an eye tracking-based, ecological paradigm, that is, a Free Visual Exploration task of naturalistic pictures. Data were analyzed from a spatiotemporal perspective. In Experiment 1, a pre-post linear mixed model (LMM) indicated a leftward attentional shift after PPC tDCS; this effect was not confirmed when the individual baseline performance was considered. In Experiment 2, FEF HD-tDCS was shown to induce a significant leftward shift of gaze position, which emerged after 6 s of picture exploration and lasted for 200 ms. The present results do not allow us to conclude on a clear efficacy of offline conventional tDCS and HD-tDCS in modulating overt visuospatial attention in an ecological setting. Nonetheless, our findings highlight a complex relationship among stimulated area, focality of stimulation, spatiotemporal aspects of deployment of attention, and the role of individual baseline performance in shaping the effects of tDCS

    An Experiment for Observing Quantum Gravity Phenomena using Twin Table-Top 3D Interferometers

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    Theories of quantum gravity based on the holographic principle predict the existence of quantum fluctuations of distance measurements that accumulate and exhibit correlations over macroscopic distances. This paper models an expected signal due to this phenomenology, and details the design and estimated sensitivity of co-located twin table-top 3D interferometers being built to measure or constrain it. The experiment is estimated to be sensitive to displacements ∼10−19 m/Hz\sim10^{-19}\,\rm{m}/\sqrt{\rm{Hz}} in a frequency band between 1 and 250 MHz, surpassing previous experiments and enabling the possible observation of quantum gravity phenomena. The experiment will also be sensitive to MHz gravitational waves and various dark matter candidates.Comment: Accepted for publication in Classical and Quantum Gravit
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