381 research outputs found

    Wave forecasting dependent from bottom roughness: The case of the Marano and Grado Lagoon

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    Several forecasting curves have been developed in order to provide a useful estimation of the wind wave field generated on shallow depths. In particular, these equations can be successfully applied in confined and sheltered basins, such as lakes, or even lagoons and semi \u2013 enclosed estuarine in coastal environments. The important role of the bottom friction dissipation in the generation process has been deeply recognized, leading to a reformulation of the available curves in terms of the equivalent bed roughness. In the present study, the recent new set of equations is considered and applied to a coastal lagoon. The results in terms of significant wave height and peak period are compared to those derived from a complete numerical model and other previous curves. The performed application corroborates and further validate the forecasting equations

    A complete morphodynamic study to face a river engineering issue

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    The last reach of the Tagliamento River, in North East Italy, is progressively changing its planimetric geometry, causing sediment deposition close to a port and preventing the regular navigation in that area. In the present paper, this river engineering issue has been addressed in a complete way, first investigating the cause which brought to the present situation, and then proposing a number of design solution to mitigate the problem. Some of them have been analyzed by means of a morphodynamic numerical model, reproducing the effects on the bottom height of an average year in terms of flow and tides. The results of each simulation are compared to those of the present situation, in order to underline any advantages of the proposed design solution

    The tidal prism as a dynamic response of a nonlinear harmonic system

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    As known, the empirical relationship between the equilibrium cross-sectional area of a lagoon inlet and the tidal prism was intuited for the first time by LeConte ["Discussion on the paper, "Notes on the improvement of river and harbor outlets in the United States"by D. A. Watt,"Trans. ASCE 55, 306-308 (1905).] and then formalized by O'Brien ["Estuary tidal prism related to entrance areas,"Civ. Eng. 1(8), 738-739 (1931)]. This relationship requires knowledge of the tidal prism, which can be estimated either using the cubature method or the current data method [Jarrett, Tidal Prism-Inlet Area Relationships (Coastal Engineering Research Center, US Army Corps of Engineers, Fort Belvoir, VA, 1976)], both of which involve the execution of a number of experimental measurements. However, these methods, besides being very expensive, can only provide the prism value in the present condition and do not allow for predictions in the case of significant morphological changes, of both natural and anthropic origin, to the tidal inlet. On the other hand, the hydrodynamic relationship, which links the tidal prism to the product of the tidal range and the basin extension, can only give a coarse estimate of the prism, especially when the value of the tide outside the lagoon is considered. In this work, we propose a simple hydrodynamic relationship based on the dynamic response of a nonlinear harmonic system. This is a relationship that requires the calibration of a single physically based parameter. Through this relationship, knowing the geometric characteristics, the bottom friction of the inlet channel, the surface of the basin, and the tide amplitude in the open sea, it is possible to estimate the tidal prism. The application of this relationship to real cases shows a good agreement with the experimental data

    THE POTENTIAL OF PHYSIOLOGICAL ANALYSIS USING ELECTROMYOGRAPHY IN THE DESIGN OF MOTORCYCLES

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    Two-wheel vehicle comfort is usually assessed by means of subjective scorings or by measuring physical quantities such as acceleration, sound pressure, etc. which do not depend on the human response. This study has chosen a different approach, which is to use electromyography for evaluating the levels of muscle activity. It focuses more specifically on comfort in relation to aerodynamic loads. The loads were simulated by a wind tunnel. ANOVA statistical analysis was used to establish the impact of aerodynamic loads and of various motorcycle models on muscle activity levels. The results showed that aerodynamic loads generally cause an increase of muscle activity, although their impact varies in relation to the design of the motorcycle: each model ofmotorcycle produces a specific distribution of activity levels among muscles. The methodology can be used for vehicle-design purposes as well as organising motorbike training programmes.Keywords: Motorcycle; Aerodynamic loads; SEM; Ergonomics; Comfor

    Investigation of genomic DNA methylation by ultraviolet resonant Raman spectroscopy

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    Cytosine plays a preeminent role in DNA methylation, an epigenetic mechanism that regulates gene expression, the misregulation of which can lead to severe diseases. Several methods are nowadays employed for assessing the global DNA methylation levels, but none of them combines simplicity, high sensitivity, and low operating costs to be translated into clinical applications. Ultraviolet (UV) resonant Raman measurements at excitation wavelengths of 272 nm, 260 nm, 250 nm, and 228 nm have been carried out on isolated deoxynucleoside triphosphates (dNTPs), on a dNTP mixture as well as on genomic DNA (gDNA) samples, commercial from salmon sperm and non-commercial from B16 murine melanoma cell line. The 228 nm excitation wavelength was identified as the most suitable energy for enhancing cytosine signals over the other DNA bases. The UV Raman measurements performed at this excitation wavelength on hyper-methylated and hypo-methylated DNA from Jurkat leukemic T-cell line have revealed significant spectral differences with respect to gDNA isolated from salmon sperm and mouse melanoma B16 cells. This demonstrates how the proper choice of the excitation wavelength, combined with optimized extraction protocols, makes UV Raman spectroscopy a suitable technique for highlighting the chemical modifications undergone by cytosine nucleotides in gDNA upon hyper- and hypo-methylation events

    Somatic disorders and antidepressant use in suicides: A population-based study from the Friuli Venezia Giulia region, Italy, 2003-2013

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    Background: Many somatic disorders are complicated by depression and increase the risk of suicide. Little is known about whether antidepressants might reduce the suicidal risk in patients with somatic disorders. Methods: Data on diagnoses and antidepressant prescriptions were derived from the Social and Health Information System of the Friuli Venezia Giulia Region. Cases were all suicides that occurred in the region during the years 2003\u20132013 and were sex- and age-matched to controls from the general population. Conditional logistic regression analysis was used to assess the association between suicide and somatic disorders. Results: The suicide rate in Friuli Venezia Giulia decreased from 11.3 to 10.7 per 100,000 inhabitants during the years 2003\u20132013, however patients with somatic disorder had a three times increased risk of suicide. Elderly somatic patients' suicide risk was twice as high as younger patients. The risk increased from 2.6 to 9.8 times as the number of comorbid disorders increased from 1 to 4 and over. Although no significant risk of suicide in patients with somatic disorders was found when patients were adherent to antidepressants, only 11.5% of the suicides was adherent in the year prior to death. Conclusions: Medical illnesses and underlying depressive symptoms may have a synergy effect on the risk of suicide, particularly in older patients and in patients with multiple morbidities. Since medically ill subjects adherent to antidepressants did not showa significant risk of suicide, early identification and adequate treatment of depression in somatic patients should be considered in order to prevent suicide
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