124 research outputs found
Paolo De Matthaeis,órgano (Colombia)
No full textConcierto interpretado por el organista Paolo de Matthaeis. Este artista es organista titular de la Basílica de Santa Agnese en Roma, de la Basílica de San Pietro in Víncoli y organista y maestro preparador en la Iglesia Santa María alla Traspontina. Inició sus estudios musicales en el piano con G Bruno, en el órgano con P. Theo Flury (O. S. B.), y en órgano y composición con Guiuseppe Agostini• posteriormente los continuó con Wijnand Van de PoI en el curso superior experimental de órgano del Conservatorio Morlaccru en Perugia
Genetic structuring and gene flow in Cerastoderma glaucum (Bivalvia: Cardiidae): evidence from allozyme variation at different geographic scale
No full textGenetic variation at 16 enzyme loci was analysed in 20 Mediterranean and I Baltic population of Cerastoderma glaucum. Spatial genetic variation at different geographic scales was investigated. In general, this species was fairly genetically structured (over all loci theta=0.088), according to the fragmentary nature of its habitat. Spatial structuring of genetic diversity was shown to follow different models, depending on the geographic scale considered: a stepping-stone model provided a good fit at a wide scale, with gene flow inversely related to geographic distance, whereas at small scale, genetic relationships among samples could not be interpreted as simply the effect of physical distance among populations. Results are discussed taking into account the intrinsic and extrinsic factors which are most likely to affect the patterns of genetic structuring in coastal marine animals
Modeling and predictive control of a new injection system for Compressed Natural Gas engines
No full textThe accurate metering of the air/fuel mixture in internal combustion engines equipped with common rail injection systems strictly depends on the injection pressure regulation. This is a critical objective to be accomplished in compressed natural gas injection systems, as the gas compressibility makes the fuel delivery process more complex. Since the design of a controller requires a model of the injection system, in this paper a physics-based state space model of an innovative compressed natural gas injection system is presented. The model parameters only depend on well defined geometrical data and fuel properties. Comparison of simulation and experimental results for different operating conditions validates the model. Further, the proposed model is used for designing a generalized predictive controller (GPC) for the injection pressure regulation. The implementation of the control law consists of simple steps. Experimental results show the effectiveness of the proposed approach
Effects of hypercapnia on peripheral vascular reactivity in elderly patients with acute exacerbation of chronic obstructive pulmonary disease
No full textBlood acid-base imbalance has important effects on vascular reactivity, which can be related to nitric oxide (NO) concentration and increased during hypercapnia. Release of NO seems to be linked to H+ and CO2 concentration and to exacerbation of chronic obstructive pulmonary disease (COPD), a common medical condition in the elderly. Flow-mediated dilation (FMD), a valuable cardiovascular risk indicator, allows assessment of endothelial-dependent vasodilation, which is to a certain extent mediated by NO. We investigated the effects of hypercapnia and acid-base imbalance on endothelial-dependent vasodilation by measurement of FMD in 96 elderly patients with acute exacerbation of COPD. Patients underwent complete arterial blood gas analysis and FMD measurement before (phase 1) and after (phase 2) standard therapy for acute exacerbation of COPD and recovery. Significant differences between phase 1 and phase 2 were observed in the mean values of pH (7.38±0.03 versus 7.40±0.02, P<0.001), pO2 (59.6±4.9 mmHg versus 59.7±3.6 mmHg, P<0.001), pCO2 (59.3±8.63 mmHg versus 46.7±5.82 mmHg, P<0.001), FMD (10.0%±2.8% versus 8.28%±2.01%, P<0.001) and blood flow rate (1.5±0.3 m/s versus 1.5±0.3 m/s, P=0.001). FMD values were positively correlated with pCO2 values (r=0.294, P=0.004) at baseline. A significant correlation was also found between relative changes in FMD and pCO2 levels, passing from phase 1 to phase 2 (r = 0.23, P=0.023). Patients with higher baseline endothelium-dependent vasodilation as evaluated by FMD showed greater modification with regard to pCO2 changes (2.6±1.39 versus 1.59±1.4, P=0.012). In conclusion, endothelium-dependent vasodilation as evaluated by FMD was elevated during hypercapnia, and varied significantly according to pCO2 changes in patients with higher baseline levels, suggesting that vascular reactivity in acute COPD exacerbations in the elderly depends on integrity of the vascular endothelium. © 2014 de Matthaeis et al
Genetic differentiation and biogeography in southern European populations of the genus Scardinius (Pisces, Cyprinidae) based on allozyme data
No full textLevels of genetic differentiation and variability were assessed in several populations and species belonging to the primary freshwater fish genus Scardinius by means of electrophoretic analyses of 28 enzymatic loci. We studied one population of S. acarnanicus and one of S. graecus, both endemic to Greece, seven populations of S. erythrophthalmus from Greece, Slovenia, northern and central Italy, and the single extant population of S. scardafa, a species endemic to central Italy. Patterns of genetic relationships placed the Greek species basal in the neighbour-joining (NJ) and maximum parsimony (MP) trees, S. scardafa and S. erythrophthalmus are sister species. Based on the molecular clock, the split between S. acarnanicus and S. graecus occurred around 4.3 Myr ago and the split between (S. acarnanicus, S. graecus) and (S. scardafa, S. erythrophthalmus) around 3.5 Myr ago, both after the Messinian lacustrine 'Lago Mare' phase of the Mediterranean. The separation between S. scardafa and S. erytbrophthalmus was more recent (0.5 Myr ago) and was probably the result of confluences between adjacent river basins during the Pleistocene. Within S. erythrophthalmus, the Greek population showed a certain degree of genetic differentiation, whereas northern and central Italian populations were nearly indistinguishable. These findings demonstrate the impact of the artificial introduction of this species into central Italy, leading to the near extinction of the endemic S. scardafa
Prediction of the Behavior of a CNG Tank Exposed to Flames
No full textThe increasing request of vehicles fuelled by Compressed Natural Gas (CNG) requires that the safety issues related to this kind of fuel should be analyzed more and more thoroughly. So far, the minimum requirement for a CNG tank is to set up a Pressure Relief Device (PRD) triggered by temperature. This work aims to develop a procedure able to perform thoroughly tank behavior analyses, in presence of fire, in order to reduce the number of expensive experimental tests and to improve the design criteria of tank safety devices. The procedure consists in the solution of the unsteady solid-fluid conjugate heat transfer problem, by means of numerical simulations, in order to evaluate the transient behavior of both the temperature field inside the solid walls of the tank and the thermo-fluid-dynamic field of the compressed gas inside it, when it is exposed to a heating source. Moreover, the melting process of the fusible plug, inside the PRD, is simulated. In order to validate this procedure, experimental tests have been carried out on a suitable test rig. Several heating conditions, even unlikely, but able to jeopardize safety, have been considered. The condition characterized by a flame located on the opposite side of the PRD has been recognized to be the most critical with respect to explosion risk. In this case, the relationship between time and tank pressure has been numerically evaluated. The fusible plug, inside the PRD, has been checked to be completely melted of the fusible plug before the pressure reaches the safety limit
Genetic and morphological differentiation in populations of the Italian freshwater Gammarus species (Crustacea Amphipoda)
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Affinità e divergenze genetiche tra i Gammaridi italiani: il caso del Gammarus italicus (Crustacea, Amphipoda)
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