It is generally argued that epilithic diatoms and macroinvertebrates are highly sensitive to changes in water quality, while only a few studies have been conducted on their response to physical disturbance. The main purpose of this research is to investigate whether these two communities respond to physical river disturbance like banks, substrate and flux alteration induced by human action.We sampled 12 high-altitude streams in the Gran Paradiso National Park, a protected area where the main human activities are limited to hiking and high-altitude pasture. The sampled stretches of the rivers were characterized with respect to their geomorphological features and possible human modifications. Water uptake for power supply, riverbed and bank modifications represented the main human activities which could determinate alterations in community structure and composition. Habitat structure was evaluated using the Southern European River Habitat (RHS-SE), while the biological status of the river has been estimated by means of the following biotic and diatomic indices: IBE, BMWP, ASPT, Ephemeroptera, Plecoptera and Trichoptera families (EPT) for macroinvertebrates, EPI-D, IBD and IPS for diatoms. A general concordance between chemical parameters and structure of biological communities was observed. On the other hand, the RHS-SE highlighted the main geomorphological features and detected some slight physical alterations, as quantified by the indices Habitat Modification Score (HMS) and Habitat Quality Assessment (HQA). In short, our findings demonstrate that morphological alterations, even if slight, affect biological diversity and the presence of some specific taxa, while biological indices are independent of the level of physical modifications.

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We show efficient elastic energy transfer and wave confinement through a graded array of resonators attached to an elastic beam. Experiments demonstrate that flexural resonators of increasing lengths allow to reduce wave scattering and to achieve the rainbow effect with local wavefield amplifications. We show that the definition of a monotonically decreasing distribution of the natural frequencies of the resonators along the wave propagation direction, is the preferable choice to increase the energy efficiency of the system. The proposed configuration is suitable for micro-fabrication, envisaging practical applications for micro-scale vibration energy harvesting.

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Precise control of elastic waves is a challenge for many applications in the field of mechanical vibrations, ultrasonic inspection, and energy harvesting. Graded arrays of resonators on elastic substrates recently revealed superior performances for broadband wave trapping and mode conversion. In this study we present elastic waveguides able to govern waves at different scales exploiting rainbow reflection, trapping and mode conversion. We investigate whether these mechanisms, and the associated control, can be used for energy harvesting or signal conversion devices.

Background: To investigate the effects of the COVID-19 lockdowns on the vasculopathic population. Methods: The Divisions of Vascular Surgery of the southern Italian peninsula joined this multicenter retrospective study conducted through cross-sectional survey. Each received a 13-point questionnaire, investigating the hospitalization rate of vascular patients in the first 11 months of the COVID-19 pandemic and in the preceding 11 months. Results: 27 out of 29 Centers were enrolled. April-December 2020 (7092 patients) vs 2019 (9161 patients): post-EVAR surveillance, treatment for Rutherford category 3 peripheral arterial disease, and asymptomatic carotid stenosis revascularization significantly decreased [1484 (16.2%) vs 1014 (14.3%), p=0.0009; 1401 (15.29%) vs 959 (13.52%), p=0.0006; and 1558 (17.01%) vs 934 (13.17%), p<0.0001, respectively]; while revascularization or major amputations for chronic limb-threatening ischemia, and urgent revascularization for symptomatic carotid stenosis significantly increased [1204 (16.98%) vs 1245 (13.59%), p<0.0001; 355 (5.01%) vs 358 (3.91%), p=0.0007; and 153 (2.16%) vs 140 (1.53%), p=0.0009, respectively]. Conclusions: The suspension of elective activities during the COVID-19 pandemic caused a significant reduction in asymptomatic carotid stenosis revascularization, treatment for Rutherford 3 peripheral arterial disease, post-EVAR surveillance. Contestually, we observed a significant increase in urgent revascularization for symptomatic carotid stenosis, and revascularization or major amputations for chronic limb-threatening ischemia.

Background: To investigate the effects of the COVID-19 lockdowns on the vasculopathic population. Methods: The Divisions of Vascular Surgery of the southern Italian peninsula joined this multicenter retrospective study. Each received a 13-point questionnaire investigating the hospitalization rate of vascular patients in the first 11 months of the COVID-19 pandemic and in the preceding 11 months. Results: 27 out of 29 Centers were enrolled. April-December 2020 (7092 patients) vs. 2019 (9161 patients): post-EVAR surveillance, hospitalization for Rutherford category 3 peripheral arterial disease, and asymptomatic carotid stenosis revascularization significantly decreased (1484 (16.2%) vs. 1014 (14.3%), p = 0.0009; 1401 (15.29%) vs. 959 (13.52%), p = 0.0006; and 1558 (17.01%) vs. 934 (13.17%), p < 0.0001, respectively), while admissions for revascularization or major amputations for chronic limb-threatening ischemia and urgent revascularization for symptomatic carotid stenosis significantly increased (1204 (16.98%) vs. 1245 (13.59%), p < 0.0001; 355 (5.01%) vs. 358 (3.91%), p = 0.0007; and 153 (2.16%) vs. 140 (1.53%), p = 0.0009, respectively). Conclusions: The suspension of elective procedures during the COVID-19 pandemic caused a significant reduction in post-EVAR surveillance, and in the hospitalization of asymptomatic carotid stenosis revascularization and Rutherford 3 peripheral arterial disease. Consequentially, we observed a significant increase in admissions for urgent revascularization for symptomatic carotid stenosis, as well as for revascularization or major amputations for chronic limb-threatening ischemia.