1,545 research outputs found

    Correlated Nanoscopic Josephson Junctions

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    We discuss correlated lattice models with a time-dependent potential across a barrier and show how to implement a Josephson-junction-like behavior. The pairing occurs by a correlation effect enhanced by the symmetry of the system. In order to produce the effect we need a mild distortion which causes avoided crossings in the many-body spectrum. The Josephson-like response involves a quasi-adiabatic evolution in the time-dependent field. Besides, we observe an inverse-Josephson (Shapiro) current by applying an AC bias; a supercurrent in the absence of electromotive force can also be excited. The qualitative arguments are supported by explicit exact solutions in prototype 5-atom clusters with on-site repulsion. These basic units are then combined in ring-shaped systems, where one of the units sits at a higher potential and works as a barrier. In this case the solution is found by mapping the low-energy Hamiltonian into an effective anisotropic Heisenberg chain. Once again, we present evidence for a superconducting flux quantization, i.e. a Josephson-junction-like behavior suggesting the build-up of an effective order parameter already in few-electron systems. Some general implications for the quantum theory of transport are also briefly discussed, stressing the nontrivial occurrence of asymptotic current oscillations for long times in the presence of bound states.Comment: 12 pages, 2 figures, to appear in J. Phys. - Cond. Ma

    Factors associated with metabolic syndrome in a Mediterranean population : role of caffeinated beverages

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    BACKGROUND: Intake of caffeinated beverages, such as coffee and tea, has been related to improvements in components of metabolic syndrome (MetS), but studies conducted in the Mediterranean region are scarce. The aim of this study was to evaluate whether or not consumption of a variety of beverages containing caffeine was associated with components of MetS in an Italian population. METHODS: From May 2009 to December 2010, a cross-sectional survey was conducted on 1889 inhabitants living in Sicily, southern Italy. Data regarding demographic characteristics, habitual beverage intake, and adherence to the Mediterranean diet were collected, and clinical information was retrieved from the general practitioners’ computer records. RESULTS: After adjusting for all covariates, coffee (odds ratio [OR] 0.43, 95% confidence interval [CI] 0.27–0.70) and tea (OR 0.51, 95% CI 0.34–0.78) were associated with MetS, whereas no association was observed between caffeine intake and MetS. Among other factors, age, body mass index, physical activity, current smoking, and adherence to Mediterranean diet were associated with having MetS. Triglycerides were inversely associated with consumption of both espresso coffee and tea. The healthy effects of such beverages were more evident in individuals with unhealthy dietary habits. CONCLUSIONS: Although no direct association between caffeine intake and MetS or its components was observed, coffee and tea consumption was significantly related to reduced odds of MetS

    Anisotropic straining of graphene using micropatterned SiN membranes

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    We use micro-Raman spectroscopy to study strain profiles in graphene monolayers suspended over SiN membranes micropatterned with holes of non-circular geometry. We show that a uniform differential pressure load ΔP\Delta P over elliptical regions of free-standing graphene yields measurable deviations from hydrostatic strain conventionally observed in radially-symmetric microbubbles. The top hydrostatic strain εˉ\bar{\varepsilon} we observe is estimated to be 0.7%\approx0.7\% for ΔP=1bar\Delta P = 1\,{\rm bar} in graphene clamped to elliptical SiN holes with axis 4040 and 20μm20\,{\rm \mu m}. In the same configuration, we report a G±G_\pm splitting of 10cm110\,{\rm cm^{-1}} which is in good agreement with the calculated anisotropy Δε0.6%\Delta\varepsilon \approx 0.6\% for our device geometry. Our results are consistent with the most recent reports on the Gr\"uneisen parameters. Perspectives for the achievement of arbitrary strain configurations by designing suitable SiN holes and boundary clamping conditions are discussed.Comment: 8 pages, 6 figure (including SI

    Association between polyphenol intake and adherence to the Mediterranean diet in Sicily, southern Italy

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    Abstract Background Mediterranean diet has been demonstrated to exert beneficial effects toward various health outcomes. Among the compounds that may be responsible for such benefits, polyphenols have been proposed as potential candidates. The aim of this study was to evaluate whether dietary polyphenols were associated with adherence to the Mediterranean diet in a Sicilian cohort. Methods A total of 1937 adults were recruited in the urban area of Catania, southern Italy. Background characteristics and dietary habits were collected through validated questionnaires. Adherence to the Mediterranean diet was evaluated through application of a validated score (MEDI-LITE score). Dietary intake of polyphenols was estimated through the Phenol-explorer database. Differences in mean intake between quartiles of the MEDI-LITE score and association between quartiles of polyphenol intake and high adherence to the Mediterranean diet (highest quartile of the score) were calculated though logistic regression analyses. Results Mean intake of most polyphenols was significantly different between quartiles of the MEDI-LITE score, being generally higher in individuals more adherent to the Mediterranean diet. Only few compounds, such as lignans, anthocyanins, and flavanones, showed a linear positive association with high adherence to the Mediterranean diet, while other polyphenol classes were associated in a non-linear manner. Among individual polyphenols, apigenin, hesperetin, naringenin, lariciresinol, matairesinol, pinoresinol, secoisolariciresinol, and ferulic acid were associated with high adherence to Mediterranean diet in a linear manner, while all the others (except for myricetin) were associated in a non-linear way. Conclusions Mean polyphenol intake was higher in individuals more adherent to the Mediterranean diet compared to less adherent. However, dietary sources of polyphenols not included in the traditional foods comprised in the Mediterranean diet may contribute to total and specific classes of polyphenols irrespectively of their inclusion within the context of the Mediterranean diet

    Population status, distribution and trophic implications of Pinna nobilis along the South-eastern Italian coast

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    The dramatic Mass Mortality Event, MME, of Pinna nobilis populations initially detected in the western Mediterranean basin, has also spread rapidly to the central and eastern basin. Unfortunately, there is still a significant lack of information on the status and health of P. nobilis, since only a fragmentary picture of the mortality rate affecting these populations is available. Regarding the Italian coast, several surveys have given only localized or point-like views on the distribution of species and the effect of the MME. Therefore, for the first time, this study investigated P. nobilis density of individuals, distribution and mortality throughout 161 surveys along 800 km of coastline in the Apulia region (South-east of Italy). The geographical scale of this investigation made it the largest ever conducted in Italy, and this was achieved through a rapid and standardized protocol. During this monitoring campaign, 90 km of linear underwater transects were surveyed, along which no live individuals were observed. This result allowed to estimate that the P. nobilis populations had totally collapsed, with a mortality rate of 100% in Apulia. The distributional pattern of the species showed a strong overlap with seagrass meadows on meso- and macro-geographical scale, however this was not the case on a micro-scale. This result evidenced that relationships between P. nobilis and seagrass meadows are not limited to the habitat patch, but cross the boundaries of seagrass leading us to suggest that the distribution of P. nobilis hold a trophic link through the cross-boundary subsidy occurring from seagrass meadows to the nearby habitat, by means of the refractory detrital pathway

    Retrofit of the existing buildings using a novel developed aerogel-based coating: results from an in-field monitoring

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    The energy retrofit of existing buildings and more in general building rehabilitation represents an important challenge in EU countries since a large part of their building stock is old, poorly insulated and affected by pathologies, i.e. mould growth, with relevant implications on users health other than aesthetical drawbacks. Unfortunately, the energy retrofit of existing buildings and particularly when dealing with historic buildings presents several issues, i.e. the compatibility between the identified solutions and the heritage value or the reduction of the internal space if internal solutions have to be adopted. An emerging solution to address the target of the energy efficiency, according to the abovementioned issues, is the application of advanced materials characterized by high thermal performance and thus allowing to keep low layer thickness. In the framework of an on-going Wall-ACE Horizon 2020 project, a set of aerogel-based novel super insulating plasters, particularly suitable for internal and external application on existing walls is under development. As far as the interior layer is concerned, so far two different aerogel-based products have been developed: an interior plaster and a thermal coating were developed respectively aimed at reducing the heating energy needs and mitigating thermal bridges mould issues. The paper reports the first results of the laboratory tests carried out on the thermal coating Moreover, a monitoring activity in a 1920s building in Torino (Italy, Lat.45°N, Long 7.65°E) was carried out to characterize the actual thermal performance of the insulating layer and to assess the technical and the hygrothermal compatibility of the intervention. The monitoring results highlight that the application of a thin thermal coating finishing layer can lead to a significant increment of the indoor surface temperature of ~1.5°C with a decrease of the wall heat losses of ~30%. Moreover, a mitigation of the effect of the thermal bridge was also observed with an increment of the node surface temperature (wall-window frame) of up to 2°C

    Environmental Impact of Dietary Choices: Role of the Mediterranean and Other Dietary Patterns in an Italian Cohort

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    Background: Current scientific literature suggests healthy dietary patterns may have less environmental impact than current consumption patterns, but most of the studies rely on theoretical modeling. The aim of this study was to assess the impact on resources (land, water, and energy) use and greenhouse gas (GHG) emissions of healthy dietary patterns in a sample of Italian adults. Methods: Participants (n = 1806) were recruited through random sampling in the city of Catania, southern Italy. Dietary consumption was assessed through a validated food frequency questionnaire (FFQ); dietary patterns were calculated through dietary scores. The specific environmental footprints of food item production/processing were obtained from various available life-cycle assessments; a sustainability score was created based on the impact of the four environmental components calculated. Results: The contribution of major food groups to the environmental footprint showed that animal products (dairy, egg, meat, and fish) represented more than half of the impact on GHG emissions and energy requirements; meat products were the stronger contributors to GHG emissions and water use, while dairy products to energy use, and cereals to land use. All patterns investigated, with the exception of the Dietary Approach to Stop Hypertension (DASH), were linearly associated with the sustainability score. Among the components, higher adherence to the Mediterranean diet and Alternate Diet Quality Index (AHEI) was associated with lower GHG emissions, dietary quality index-international (DQI-I) with land use, while Nordic diet with land and water use. Conclusions: In conclusion, the adoption of healthy dietary patterns involves less use of natural resources and GHG emissions, representing eco-friendlier options in Italian adults

    Legume consumption and CVD risk: a systematic review and meta-analysis

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    Objective: The aim of the present study was to systematically review and perform a meta-analysis of prospective cohort studies exploring the association between dietary legume consumption and CVD risk, including CHD and stroke. Design: The PubMed and EMBASE databases were searched up to December 2015. A meta-analysis of the highest v. lowest (reference) category of dietary legume consumption was performed through random-effects models. Results: Fourteen studies conducted on eleven cohorts and accounting for a total of 367 000 individuals and 18 475 cases of CVD (7451 CHD and 6336 stroke cases) were considered for the analyses. Compared with lower legume consumption, the highest category of exposure was associated with a decreased risk of 10 % in both CVD and CHD (relative risk=0·90; 95 % CI 0·84, 0·97) with no or little evidence of heterogeneity and no publication bias. Null results were found regarding legume consumption and stroke risk. No substantial confounding factors were evident in stratified analyses. Conclusions: Legume consumption was associated with lower risk of CVD. Legumes' intrinsic characteristics, because they are often part of an overall healthy diet, or because they are a substitute for unhealthy sources of protein may potentially explain the current findings. Keywords: CVD; Fibre; Legumes; Meta-analysis; Mortality

    Health related quality of life in colorectal cancer patients: state of the art

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    Proceedings of the 26th National Congress of the Italian Society of Geriatric Surgery Silvestro Canonico, Bruno Amato and Alessandro Puzziello This supplement has not been sponsored. The source of funding used to cover open access publication charges is declared by the authors in each article. Articles have undergone the journal's standard review process for supplements. The supplement editors declare they have no competing interests. Conference 26th National Congress of the Italian Society of Geriatric Surgery 19-22 June 2013 Naples, ItalyBACKGROUND: Colorectal cancer (CRC) is the third most commonly diagnosed cancer in males and the second in females with a progressive increase in prevalence in industrialized countries. The loss of health due to the cancer and/or the consequence of the treatment may result in psychophysical, functional and social impairment; all of these affect health-related quality of life (QoL). DESCRIPTION: The most frequently CRC-specific QoL questionnaires is the FACT-C. QoL is not only important for the well-being of cancer patient but it also influences survival and response to therapy. Many studies investigated various determinants involved in the assessment of QoL in CRC, suggesting that symptoms, surgical procedures and the number of comorbidity significantly affected QoL. CONCLUSION: Despite that CRC patients have a relatively good QoL compared with the general population, a wide range of intervention could be undertaken to improve their QoL. The finding of this review may be useful for cancer clinicians in taking therapy and surveillance-related decisions. However, future research should be directed to large-scale prospective studies using well validated QoL instruments to facilitate comparison of results.Funding for this article has come from University funds.S
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