3,197 research outputs found
Efficient Analysis for the Design Refinement of Large Multilayered Printed Reflectarrays
In this paper, we present an efficient numerical technique for the analysis of a reflectarray and its design refinement by the characterization of the “actual” influence of each radiating element when embedded in the antenna structure. The method makes use of the MLayAIM, a fast full-wave formulation suitable for the analysis of electrically large multilayered printed arrays which have one or more planar metallizations and vertical conductors. The low numerical complexity of the analysis method allows the development of a recursive procedure that, starting from the equivalent currents relevant to each cell of the reflectarray when this is immersed in the actual antenna layout, calculates the real phase-shift introduced by each radiating element and corrects its dimensions to better fit the antenna requirements
Attenuating surface gravity waves with mechanical metamaterials
4noMetamaterials and photonic/phononic crystals have been successfully developed in recent years to achieve advanced wave manipulation and control, both in electromagnetism and mechanics. However, the underlying concepts are yet to be fully applied to the field of fluid dynamics and water waves. Here, we present an example of the interaction of surface gravity waves with a mechanical metamaterial, i.e., periodic underwater oscillating resonators. In particular, we study a device composed of an array of periodic submerged harmonic oscillators whose objective is to absorb wave energy and dissipate it inside the fluid in the form of heat. The study is performed using a state-of-the-art direct numerical simulation of the Navier-Stokes equation in its two-dimensional form with free boundary and moving bodies. We use a volume of fluid interface technique for tracking the surface and an immersed boundary method for the fluid-structure interaction. We first study the interaction of a monochromatic wave with a single oscillator and then add up to four resonators coupled only fluid-mechanically. We study the efficiency of the device in terms of the total energy dissipation and find that by adding resonators, the dissipation increases in a nontrivial way. As expected, a large energy attenuation is achieved when the wave and resonators are characterized by similar frequencies. As the number of resonators is increased, the range of attenuated frequencies also increases. The concept and results presented herein are of relevance for coastal protection applications.openpartially_openembargoed_20220426De Vita F.; De Lillo F.; Bosia F.; Onorato M.De Vita, F.; De Lillo, F.; Bosia, F.; Onorato, M
Estimating annual groundwater recharge coefficient for karst aquifers of the southern Apennines (Italy)
Abstract. To assess the mean annual groundwater recharge of the karst aquifers in the southern Apennines (Italy), the estimation of the mean annual groundwater recharge coefficient (AGRC) was conducted by means of an integrated approach based on hydrogeological, hydrological, geomorphological, land use and soil cover analyses. Starting from the hydrological budget equation, the coefficient was conceived as the ratio between the net groundwater outflow and the precipitation minus actual evapotranspiration (P − ETR) for a karst aquifer. A large part of the southern Apennines, which is covered by a meteorological network containing 40 principal karst aquifers, was studied. Using precipitation and air temperature time series gathered through monitoring stations operating in the period 1926–2012, the mean annual P − ETR was estimated, and its distribution was modelled at a regional scale by considering the orographic barrier and rain shadow effects of the Apennine chain, as well as the altitudinal control. Four sample karst aquifers with available long spring discharge time series were identified for estimating the AGRC. The resulting values were correlated with other parameters that control groundwater recharge, such as the extension of outcropping karst rocks, morphological settings, land use and covering soil type. A multiple linear regression between the AGRC, lithology and the summit plateau and endorheic areas was found. This empirical model was used to assess the AGRC and mean annual groundwater recharge in other regional karst aquifers. The coefficient was calculated as ranging between 50 and 79%, thus being comparable with other similar estimations carried out for karst aquifers of European and Mediterranean countries. The mean annual groundwater recharge for karst aquifers of the southern Apennines was assessed by these characterizations and validated by a comparison with available groundwater outflow measurements. These results represent a deeper understanding of an aspect of groundwater hydrology in karst aquifers which is fundamental for the formulation of appropriate management models of groundwater resources at a regional scale, also taking into account mitigation strategies for climate change impacts. Finally, the proposed hydrological characterizations are also supposed to be useful for the assessment of mean annual runoff over carbonate mountains, which is another important topic concerning water management in the southern Apennines
Hydro-geomorphological modelling of ash-fall pyroclastic soils for debris flow initiation and groundwater recharge in Campania (southern Italy)
Carbonate mountain ranges surrounding volcanic centers in the Campania region of southern Italy are covered by discontinuous ash-fall pyroclastic deposits of variable thicknesses. The cover thickness and stratigraphy are relevant to hydrological controls on both rainfall-induced landslides and groundwater recharge. To improve understanding of the hydrologic regimes within the pyroclastic soil mantle, a hydrological monitoring station was installed upslope of a debris flow source area in the Sarno Mountains. Monitoring results demonstrate consistently unsaturated conditions, strong seasonal and inter-annual variations in pressure head, and delayed and damped dynamics at different depths related to rainfall and evapotranspiration patterns. Frequencies of recorded pressure head time series were analyzed to quantify the seasonal hydrological regime of the cover as a whole, as well as variations within individual soil horizons. For the whole ash-fall pyroclastic soil cover, variable seasonal frequencies of pressure head were recognized exceeding landslide alert and groundwater recharge threshold values. Analysis of frequencies for individual soil horizons showed a strongly delayed timing determining in winter and summer an opposite hydrological behavior between the shallowest and deepest soil horizons. A model that accounts for topographic variations in cover thickness and these hydrological regimes is proposed to quantify hydro-geomorphological controls on debris flows triggering and groundwater recharge. The model is based on the estimation of ash-fall pyroclastic soil thickness along slopes by the total thickness fallen in a given area and an inverse relationship with slope angle, allowing the assessment at the distributed scale over peri-volcanic mountainous areas. Moreover, it links the spatially variable thicknesses of ash-fall pyroclastic soils to the amount of soil water storage allowing the assessment of frequency of hydrological conditions leading to debris flow initiation and groundwater recharge
Healthcare and economic burden of ANCA-associated vasculitis in Italy: an integrated analysis from clinical and administrative databases
ANCA-associated vasculitides (AAV) comprise a group of systemic vasculitides characterized by inflammation of small-sized blood vessels leading to multi-organ involvement. The worldwide annual incidence of AAV ranges from 1.2 to 3.3 cases per 100 000 individuals with a prevalence of 4.6\u201342.1 cases per 100 000 individuals. The prevalence of AAV is geographically heterogeneous; therefore, regional epidemiological studies can be more informative to improve health care systems. Even though clinicians are aware that the healthcare burden and the risk of hospitalization of AAV appear high, data on hospitalization and cost of illness due to AAV are still scarce or even lacking. This study aims to characterize the economic burden of AAV in Friuli Venezia Giulia (FVG), Italy. Thus, a retrospective study was conducted through the integration of many administrative health databases of the FVG as the source of information. From data integration, we estimated that more than two-thirds of AAV patients showed at least one hospitalization in their medical history, most frequently caused by the disease itself or superimposed infections. Around 10% of patients developed end-stage renal disease. In an 8-year follow-up, the overall healthcare cost was \u20ac 1,215,078, corresponding to \u20ac 6,168 patient-year. ANCA-positive patients showed much higher costs than ANCA-negative patients did. Overall, AAV are rare diseases, but imply very high healthcare costs. Early diagnosis and optimal treatment probably still remain unmet needs for AAV
Coupled decadal variability of the North Atlantic Oscillation, regional rainfall and karst spring discharges in the Campania region (southern Italy)
Abstract. Thus far, studies on climate change have focused mainly on the variability of the atmospheric and surface components of the hydrologic cycle, investigating the impact of this variability on the environment, especially with respect to the risks of desertification, droughts and floods. Conversely, the impacts of climate change on the recharge of aquifers and on the variability of groundwater flow have been less investigated, especially in Mediterranean karst areas whose water supply systems depend heavily upon groundwater exploitation. In this paper, long-term climatic variability and its influence on groundwater recharge were analysed by examining decadal patterns of precipitation, air temperature and spring discharges in the Campania region (southern Italy), coupled with the North Atlantic Oscillation (NAO). The time series of precipitation and air temperature were gathered over 90 yr, from 1921 to 2010, using 18 rain gauges and 9 air temperature stations with the most continuous functioning. The time series of the winter NAO index and of the discharges of 3 karst springs, selected from those feeding the major aqueducts systems, were collected for the same period. Regional normalised indexes of the precipitation, air temperature and karst spring discharges were calculated, and different methods were applied to analyse the related time series, including long-term trend analysis using smoothing numerical techniques, cross-correlation and Fourier analysis. The investigation of the normalised indexes highlighted the existence of long-term complex periodicities, from 2 to more than 30 yr, with differences in average values of up to approximately ±30% for precipitation and karst spring discharges, which were both strongly correlated with the winter NAO index. Although the effects of the North Atlantic Oscillation (NAO) had already been demonstrated in the long-term precipitation and streamflow patterns of different European countries and Mediterranean areas, the results of this study allow for the establishment of a link between a large-scale atmospheric cycle and the groundwater recharge of carbonate karst aquifers. Consequently, the winter NAO index could also be considered as a proxy to forecast the decadal variability of groundwater flow in Mediterranean karst areas
Maintenance bevacizumab beyond first-line paclitaxel plus bevacizumab in patients with Her2-negative hormone receptor-positive metastatic breast cancer. Efficacy in combination with hormonal therapy
Background: Data on efficacy of bevacizumab (B) beyond first-line taxane -including regimen (BT) as first-line treatment are lacking. Although preclinical results that anti-angiogenic agents combined with hormonal therapy (HT) could be active, no clinical data exist about combination of maintenance Bevacizumab (mBev) with HT.Methods: Thirty-five patients who experienced a response after first-line BT, were given mBev at the dose of 15 mg/kg every 3 weeks. Among 30 pts with hormonal receptor-positive metastatic breast cancer (MBC), 20 (66.6%) received HT with mBev (mHTBev). Objective of the study was the outcome and safety of mBev and in two groups of patients receiving HT or not.Results: Complete response and partial response was achieved/maintained in 4 (11.4%) and 13 (37.1%) patients, respectively (overall response rate: 48.5%). Clinical benefit was obtained on 23 patients (65.7%). Median of mBev PFS and clinical benefit were 6.8 months (95% CI: 0.8-12.7) and 17.1 months (95% CI :12.2-21.9), respectively. Median PFS of patients who received mHTBev was longer than mBev without HT (13 months and 4.1 months, respectively, p = 0.05). The most common severe toxicities were proteinuria (11.4%) and hypertension (8.5%). No additional toxicity was observed with HTBev.Conclusion: Maintenance bevacizumab with or without anti-hormonal therapy in patients with hormone receptor positive breast cancer is tolerable and associated with long-term clinical outcome; these results encourage the strategy of prolonging bevacizumab until progression in combination with anti-hormonal agents
Seasonal and event-based hydrological and slope stability modeling of pyroclastic fall deposits covering slopes in Campania (Southern Italy)
The pyroclastic fall deposits mantling mountain slopes in the Campania region (Southern Italy) represent one of the most studied geomorphological frameworks of the world regarding rainfall-induced debris flows threating urban areas. The proposed study focused on advancing knowledge about the hydrological response of pyroclastic fall coverings from the seasonal to event-based time scales, leading to the initiation of slope instability. The study was based on two consequential tasks. The first was the analysis of a six-year monitoring of soil pressure head carried out in a sample area of the Sarno Mountains, located above a debris flow initiation zone. The second was based on coupled hydrological and slope stability modeling performed on the physical models of slopes, which were reconstructed by empirical correlations between the slope angle, total thickness, and stratigraphic settings of pyroclastic fall deposits mantling slopes. The results obtained were: (a) The understanding of a soil pressure head regime of the volcaniclastic soil mantle, always ranging in unsaturated conditions and characterized by a strong seasonal variability depending on precipitation patterns and the life cycle of deciduous chestnut forest; and (b) the reconstruction through a deterministic approach of seasonal intensity-duration rainfall thresholds related to different morphological conditions
AB0521 COST OF ILLNESS OF ANCA-ASSOCIATED VASCULITIS IN ITALY: DATA LINKAGE ANALYSIS OF MULTIPLE CLINICAL AND ADMINISTRATIVE DATABASES IN THE PROVINCE OF UDINE, ITALY
Background:ANCA-associated vasculitides (AAV) are a group of systemic vasculitis carrying a high risk of hospitalization because the multiorgan involvement, the acute nature of some clinical manifestations, the chronic but very disabling course of some other manifestations and finally the risk of severe infections due to chronic glucocorticoid and immunosuppressor administration. However, data on cost of illness due to AAV are lacking.Objectives:to estimate the cost of illness in patients suffering from AAV in the province of Udine (about 500,000 inhabitants), Friuli Venezia Giulia (FVG), Italy, from year 2010 to 2018.Methods:integration of the information coming from many administrative databases were used to this end. The Regional Health Information System of FVG was used as the source of information for this retrospective cohort study. The system covers the entire regional population and includes various electronic health administrative databases that can be linked with one another on an individual basis through a unique encrypted identifier. In particular, the following databases were matched: the database of the health care beneficiaries (including demographic information and the residential history of all of the subjects living in FVG), the hospital discharge database, the database of exemptions from medical charges, the database of the laboratories. The population under study was selected based on the following inclusion criteria: patients were residents in the province of Udine and they had to carry the exemption code for AAV, including GPA, or EGPA, or MPA. This population was observed from 2010 to 2018.Results:57 patients (201 patient-years) with AAV were identified. They were ANCA-positive in 44/57 (77%). GPA, EGPA and MPA was diagnosed in 18 (31,6%), 15 (26,3%), 11 (19,3%) patients, respectively. The mean age at diagnosis was 54,5 (17,5) years. The disease itself was the main cause of hospitalization in almost half of the hospital discharges (60/126, 47,6%). Four patients died during the observation period due to vasculitis itself (1), pneumonia (2), or haematological malignancy (1). Time to the first event (death or hospitalization) was significantly higher in ANCA-negative AAV patients than in ANCA-positive AAV patients (p=0,03, Log-Rank test), ANCA-positive AAV patients having a three-times higher risk (HR 3,38 95%CI 1,13-10,08, p=0,03). Total estimated cost was € 1,215,078, corresponding to € 6,168 patient-year. Costs for ANCA-positive AAV patients were much higher than those for ANCA-negative AAV patients (€ 1,115,253 vs € 99,825, and € 7058 per person-year vs € 2,559 per person-year, respectively). GPA and MPA showed the highest costs if compared to EGPA [GPA: € 239,168 (€ 5199 per person-year) vs MPA: € 281,502 (€ 4771 per person-year) vs EGPA: € 214,287 (2329 per person-year), respectively]. Costs for hospitalization were the highest [€ 734,957 (€ 3731 per person-year) vs other costs € 480,121 (€ 2437 per person-year)].Conclusion:costs for AAV are very high, confirming the high health care burden of this illness. Management of ANCA-positive patients rather than ANCA-negative patients was burdened by the highest costs. GPA and MPA showed the highest direct costs for hospitalization, which very frequently occurred due to the vasculitis itself.Disclosure of Interests:Luca Quartuccio Consultant of: Abbvie, Bristol, Speakers bureau: Abbvie, Pfizer, Elena Treppo: None declared, Salvatore De Vita Consultant of: Roche, GSK, Speakers bureau: Roche, GSK, Novartis, Francesca Valent: None declare
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