Università degli Studi di Perugia
Recent publications
The growing need for assessing the integrity of aging monumental structures by means of cost-effective and not-destructive techniques has driven significant scientific interest in vibration-based structural health monitoring (SHM) procedures, allowing to track changes in selected damage-sensitive structural parameters. However, the evaluation of a healthy or damaged state from the acquired monitoring data is often a data-driven process that can be subjected to a large amount of uncertainty, resulting in false positives and false negatives. Hence, the main idea behind this work focuses on handling the main issues related to the uncertainty management by exploiting the aggregation of different sources of information. In this context, this study is aimed at detecting and locating structural damages in monumental structures with the aid of a data fusion approach including vibration-based system identification, Bayesian-based finite element (FE) model updating and visual inspections. As a preliminary step, potential damage-sensitive sections are defined on the basis of nonlinear static analyses (NLSA) performed on a calibrated FE model and/or engineering judgment (EJ). Then, a surrogate model is established enabling to transfer knowledge from the monitoring data to the updated numerical models and to solve the inverse problem aimed at deriving the posterior statistics of the uncertain parameters. The effectiveness of the proposed approach is demonstrated by using 1-year of recorded data acquired in a monumental structure named Consoli Palace, located in Umbria, central Italy, a region characterized by high seismic hazard. The palace has been continuously monitored by the Authors since 2017 using dynamic, static and environmental sensors.
A fully non-linear PFEM platform developed for coupled flow and deformation processes in saturated structured soils is employed in this work to explore the possibility of modeling the occurrence of strain localization and the evolution of the displacement field in the post-localization regime without the pathological mesh-dependence typically observed in conventional non-linear FEM simulation. The proposed formulation adopts an isotropic hardening elastoplastic model for bonded geomaterials, developed in the framework of multiplicative plasticity, equipped with non-local hardening laws of the integral type for both density- and bonding-related internal variables. These hardening laws provide the material with an internal length scale based on the size of the neighborhood where the non-local averaging is performed. A number of PFEM simulations of plane strain compression tests on ideal calcarenite specimens have been performed to explore the convergence of the numerical solution in the post-localization regime as the element size is reduced. The convergence study is focused on simulations with non-uniform, adaptive discretizations, exploring the convergence of the solution as the adopted minimum element size of the mesh is reduced. The results of the convergence study demonstrate the effectiveness of the adopted non-local approach in eliminating the pathological mesh-dependence in presence of strain localization, in the context of h-adaptive PFEM simulations.
In this research paper a new numerical model is developed to predict the leakage effect occurring at a pipeline junction. This model is based on the characteristic method. The two hydraulic singularities (leakage and junction) are taken as superposed boundary conditions that are located in the same section. This study allows locating a leak by separating its effect on the temporal pressure history from that of the junction. A numerical test based on different formulae shows the interest of a new approach for detecting and sizing a leak. The method uses transient pressure waves initiated by the sudden closure of a downstream shut-off valve. The effect of the leakage and pipe-geometrical-characteristics-change at the junction of two lines are separated and a new procedure of locating and sizing the leak is also investigated in the case of shrinkage. The shrinkage causes a pressure increase but the leak signature appears on the pressure time evolution as pressure drop. This finding facilitates the distinction between the effects of the two superposed singularities on pressure history. The friction is neglected to calculate the leak location and size. The sensitivity analysis either in sizing or locating leak is investigated to select the suitable formula. KeywordsSuperposed singularitiesLocalization techniqueMethod of characteristicsPipe-junctionPressure signalTransient analysis
Innovators are creative people who can conjure the groundbreaking ideas that represent the main engine of innovative organizations. Past research has extensively investigated who innovators are and how they behave in work-related activities. In this paper, we suggest that it is necessary to analyze how innovators behave in other contexts, such as in informal communication spaces, where knowledge is shared without formal structure, rules, and work obligations. Drawing on communication and network theory, we analyze about 38,000 posts available in the intranet forum of a large multinational company. From this, we explain how innovators differ from other employees in terms of social network behavior and language characteristics. Through text mining, we find that innovators write more, use a more complex language, introduce new concepts/ideas, and use positive but factual-based language. Understanding how innovators behave and communicate can support the decision-making processes of managers who want to foster innovation.
We present a scanning tunneling microscopy (STM) and ab-initio study of the anisotropic superconductivity of 2H-NbSe 2 in the charge-density-wave (CDW) phase. Differential-conductance spectra show a clear double-peak structure, which is well reproduced by density functional theory simulations enabling full k - and real-space resolution of the superconducting gap. The hollow-centered (HC) and chalcogen-centered (CC) CDW patterns observed in the experiment are mapped onto separate van der Waals layers with different electronic properties. We identify the CC layer as the high-gap region responsible for the main STM peak. Remarkably, this region belongs to the same Fermi surface sheet that is broken by the CDW gap opening. Simulations reveal a highly anisotropic distribution of the superconducting gap within single Fermi sheets, setting aside the proposed scenario of a two-gap superconductivity. Our results point to a spatially localized competition between superconductivity and CDW involving the HC regions of the crystal.
Landslides are considered as major natural hazards that cause enormous property damages and fatalities in Qinghai-Tibetan Plateau (QTP). In this article, we evaluated the landslide susceptibility, and its spatial differencing in the whole Qinghai-Tibetan Plateau region using five state-of-the-art learning algorithms; deep neural network (DNN), logistic regression (LR), Naïve Bayes (NB), random forest (RF), and support vector machine (SVM), differing from previous studies only in local areas of QTP. The 671 landslide events were considered, and thirteen landslide conditioning factors (LCFs) were derived for database generation, including annual rainfall, distance to drainage $${(\mathrm{Ds}}_{\mathrm{d}})$$ ( Ds d ) , distance to faults $${(\mathrm{Ds}}_{\mathrm{f}})$$ ( Ds f ) , drainage density ( $${D}_{d})$$ D d ) , elevation (Elev), fault density $$({F}_{d})$$ ( F d ) , lithology, normalized difference vegetation index (NDVI), plan curvature $${(\mathrm{Pl}}_{\mathrm{c}})$$ ( Pl c ) , profile curvature $${(\mathrm{Pr}}_{\mathrm{c}})$$ ( Pr c ) , slope $${(S}^{^\circ })$$ ( S ∘ ) , stream power index (SPI), and topographic wetness index (TWI). The multi-collinearity analysis and mean decrease Gini (MDG) were used to assess the suitability and predictability of these factors. Consequently, five landslide susceptibility prediction (LSP) maps were generated and validated using accuracy, area under the receiver operatic characteristic curve, sensitivity, and specificity. The MDG results demonstrated that the rainfall, elevation, and lithology were the most significant landslide conditioning factors ruling the occurrence of landslides in Qinghai-Tibetan Plateau. The LSP maps depicted that the north-northwestern and south-southeastern regions (< 32% of total area) were at a higher risk to landslide compared to the center, west, and northwest of the area (> 45% of total area). Moreover, among the five models with a high goodness-of-fit, RF model was highlighted as the superior one, by which higher accuracy of landslide susceptibility assessment and better prone areas management in QTP can be achieved compared to previous results. Graphical Abstract
Background and purpose In the retrospective-prospective multi-center "Blue Sky Radiomics” study (NCT04364776), we plan to test a pre-defined radiomic signature in a series of stage III unresectable NSCLC patients undergoing chemoradiotherapy and maintenance immunotherapy. As a necessary preliminary step, we explore the influence of different image-acquisition parameters on radiomic features’ reproducibility and apply methods for harmonization. Material and methods We identified the primary lung tumor on two computed tomography (CT) series for each patient, acquired before and after chemoradiation with i.v. contrast medium and with different scanners. Tumor segmentation was performed by two oncological imaging specialists (thoracic radiologist and radio-oncologist) using the Oncentra Masterplan® software. We extracted 42 radiomic features from the specific ROIs (LIFEx). To assess the impact of different acquisition parameters on features extraction, we used the Combat tool with nonparametric adjustment and the longitudinal version (LongComBat). Results We defined 14 CT acquisition protocols for the harmonization process. Before harmonization, 76% of the features were significantly influenced by these protocols. After, all extracted features resulted in being independent of the acquisition parameters. In contrast, 5% of the LongComBat harmonized features still depended on acquisition protocols. Conclusions We reduced the impact of different CT acquisition protocols on radiomic features extraction in a group of patients enrolled in a radiomic study on stage III NSCLC. The harmonization process appears essential for the quality of radiomic data and for their reproducibility. ClinicalTrials.gov Identifier : NCT04364776, First Posted:April 28, 2020, Actual Study Start Date: April 15, 2020, https://clinicaltrials.gov/ct2/show/NCT04364776 .
The current concept of clinical high-risk(CHR) of psychosis relies heavily on “below-threshold” (i.e. attenuated or limited and intermittent) psychotic positive phenomena as predictors of the risk for future progression to “above-threshold” positive symptoms (aka “transition” or “conversion”). Positive symptoms, even at attenuated levels are often treated with antipsychotics (AP) to achieve clinical stabilization and mitigate the psychopathological severity. The goal of this study is to contextually examine clinicians’ decision to prescribe AP, CHR individuals’ decision to take AP and psychosis conversion risk in relation to prodromal symptoms profiles. CHR individuals ( n = 600) were recruited and followed up for 2 years between 2016 and 2021. CHR individuals were referred to the participating the naturalistic follow-up study, which research procedure was independent of the routine clinical treatment. Clinical factors from the Structured Interview for Prodromal Syndromes (SIPS) and global assessment of function (GAF) were profiled via exploratory factor analysis (EFA), then the extracted factor structure was used to investigate the relationship of prodromal psychopathology with clinicians’ decisions to AP-prescription, CHR individuals’ decisions to AP-taking and conversion to psychosis. A total of 427(71.2%) CHR individuals were prescribed AP at baseline, 532(88.7%) completed the 2-year follow-up, 377(377/532, 70.9%) were taken AP at least for 2 weeks during the follow-up. EFA identified six factors (Factor-1-Negative symptoms, Factor-2-Global functions, Factor-3-Disorganized communication & behavior, Factor-4-General symptoms, Factor-5-Odd thoughts, and Factor-6-Distorted cognition & perception). Positive symptoms (Factor-5 and 6) and global functions (Factor-2) factors were significant predictors for clinicians’ decisions to AP-prescription and CHR individuals’ decisions to assume AP, whereas negative symptoms (Factor-1) and global functions (Factor-2) factors predicted conversion. While decisions to AP-prescription, decisions to AP-taking were associated to the same factors (positive symptoms and global functions), only one of those was predictive of conversion, i.e. global functions. The other predictor of conversion, i.e. negative symptoms, did not seem to be contemplated both on the clinician and patients’ sides. Overall, the findings indicated that a realignment in the understanding of AP usage is warranted.
Background Beckwith–Wiedemann syndrome (BWS) and Pseudohypoparathyroidism type 1B (PHP1B) are imprinting disorders (ID) caused by deregulation of the imprinted gene clusters located at 11p15.5 and 20q13.32, respectively. In both of these diseases a subset of the patients is affected by multi-locus imprinting disturbances (MLID). In several families, MLID is associated with damaging variants of maternal-effect genes encoding protein components of the subcortical maternal complex (SCMC). However, frequency, penetrance and recurrence risks of these variants are still undefined. In this study, we screened two cohorts of BWS patients and one cohort of PHP1B patients for the presence of MLID, and analysed the positive cases for the presence of maternal variants in the SCMC genes by whole exome-sequencing and in silico functional studies. Results We identified 10 new cases of MLID associated with the clinical features of either BWS or PHP1B, in which segregate 13 maternal putatively damaging missense variants of the SCMC genes. The affected genes also included KHDC3L that has not been associated with MLID to date. Moreover, we highlight the possible relevance of relatively common variants in the aetiology of MLID. Conclusion Our data further add to the list of the SCMC components and maternal variants that are involved in MLID, as well as of the associated clinical phenotypes. Also, we propose that in addition to rare variants, common variants may play a role in the aetiology of MLID and imprinting disorders by exerting an additive effect in combination with rarer putatively damaging variants. These findings provide useful information for the molecular diagnosis and recurrence risk evaluation of MLID-associated IDs in genetic counselling.
Introduction Several functional neuroimaging studies on healthy controls and patients with migraine with aura have shown that the activation of functional networks during visual stimulation is not restricted to the striate system, but also includes several extrastriate networks. Methods Before and after 4 min of visual stimulation with a checkerboard pattern, we collected functional MRI in 21 migraine with aura (MwA) patients and 18 healthy subjects (HS). For each recording session, we identified independent resting-state networks in each group and correlated network connection strength changes with clinical disease features. Results Before visual stimulation, we found reduced connectivity between the default mode network and the left dorsal attention system (DAS) in MwA patients compared to HS. In HS, visual stimulation increases functional connectivity between the independent components of the bilateral DAS and the executive control network (ECN). In MwA, visual stimulation significantly improved functional connectivity between the independent component pairs salience network and DAS, and between DAS and ECN. The ECN Z-scores after visual stimulation were negatively related to the monthly frequency of aura. Conclusions In individuals with MwA, 4 min of visual stimulation had stronger cognitive impact than in healthy people. A higher frequency of aura may lead to a diminished ability to obtain cognitive resources to cope with transitory but important events like aura-related focal neurological symptoms.
Background Fournier’s gangrene (FG) is a necrotizing fasciitis caused by aerobic and anaerobic bacterial infection that involves genitalia and perineum. Males, in their 60 s, are more affected with 1.6 new cases/100.000/year. Main risk factors are diabetes, malignancy, inflammatory bowel disease. FG is a potentially lethal disease with a rapid and progressive involvement of subcutaneous and fascial plane. A multimodal approach with surgical debridement, antibiotic therapy, intensive support care, and hyperbaric oxygen therapy (HBOT) is often needed. We present the inpatient management of an FG case during the Covid-19 pandemic period. A narrative review of the Literature searching “Fournier’s gangrene”, “necrotizing fasciitis” on PubMed and Scopus was performed. Case presentation A 60 years old man affected by diabetes mellitus, with ileostomy after colectomy for ulcerative colitis, was admitted to our Emergency Department with fever and acute pain, edema, dyschromia of right hemiscrotum, penis, and perineal region. Computed tomography revealed air-gas content and fluid-edematous thickening of these regions. Fournier’s Gangrene Severity Index was 9. A prompt broad-spectrum antibiotic therapy with Piperacillin/Tazobactam, Imipenem and Daptomycin, surgical debridement of genitalia and perineal region with vital tissue exposure, were performed. Bedside daily surgical wound medications with fibrine debridement, normal saline and povidone-iodine solutions irrigation, iodoform and fatty gauze application, were performed until discharge on the 40 th postoperative day. Every 3 days office-based medication with silver dressing, after normal saline and povidone-iodine irrigation and fibrinous tissue debridement, was performed until complete re-epithelialization of the scrotum on the 60 th postoperative day. Conclusions FG is burdened by a high mortality rate, up to 30%. In the literature, HBOT could improve wound restoration and disease-specific survival. Unfortunately, in our center, we do not have HBOT. Moreover, one of the pandemic period problems was the patient’s displacement and outpatient hospital management. For all these reasons we decided for a conservative inpatient management. Daily cleaning of the surgical wound allowed to obtain its complete restoration avoiding surgical graft and hyperbaric oxygen chamber therapy, without foregoing optimal outcomes.
Background The rate of chronic drooling in children older than 4 years is 0.5%, but it rises to 60% in those with neurological disorders. Physical and psychosocial consequences lead to a reduction in the quality of Life (QoL) of affected patients; however, the problem remains under-recognized and under-treated. We conducted an Italian consensus through a modified Delphi survey to discuss the current treatment paradigm of drooling in pediatric patients with neurological disorders. Methods After reviewing the literature, a board of 10 experts defined some statements to be administered to a multidisciplinary panel through an online encrypted platform. The answers to the questions were based on a 1–5 Likert scale (1 = strongly disagree; 5 = strongly agree). The scores were grouped into 1–2 (disagreement) and 4–5 (agreement), while 3 was discarded. The consensus was reached when the sum of the disagreement or agreement was ≥75%. Results Fifteen statements covered three main topics, namely clinical manifestations and QoL, quantification of drooling, and treatment strategies. All statements reached consensus (≥75% agreement). The 55 Italian experts agreed that drooling should be assessed in all children with complex needs, having a major impact on the QoL. Attention should be paid to investigating posterior hypersalivation, which is often neglected but may lead to important clinical consequences. Given that the severity of drooling fluctuates over time, its management should be guided by the patients’ current needs. Furthermore, the relative lack of validated and universal scales for drooling quantification limits the evaluation of the response to treatment. Finally, the shared therapeutic paradigm is progressive, with conservative treatments preceding the pharmacological ones and reserving surgery only for selected cases. Conclusion This study demonstrates the pivotal importance of a multidisciplinary approach to the management of drooling. National experts agree that progressive treatment can reduce the incidence of complications, improve the QoL of patients and caregivers, and save healthcare resources. Finally, this study highlights how the therapeutic strategy should be reconsidered over time according to the available drugs on the market, the progression of symptoms, and the patients’ needs.
Crooked functions are combinatorial objects of great interest. It is already known that the only monomial and binomial crooked functions are quadratic. In this paper, we investigate conditions on the shape of a polynomial to be crooked. Furthermore, the notion of exceptional crooked is introduced, similarly to those of APN or PN exceptional functions. Via a connection with algebraic varieties over finite fields, we provide non-existence results of exceptional crooked functions.
This note is motivated by recent work by Feng et al. (2021) which studies Novák’s conjecture for Steiner Triple Systems and extends it to cyclic Steiner 2-designs, and more generally to cyclic 2-designs. Here we consider instead a generalization to cyclic k-cycle systems: we show that in this setting the generalized conjecture is false for k≥5, and construct some families of counterexamples which arise.
An extensive, representative, and, multi-country tailored survey questionnaire eliciting social practices with heat as an energy service and the relative perceptions about heating devices was submitted to a randomized sample of more than 6,000 potential end-users in Europe within the framework of the Horizon 2020 project SWS-HEATING. The project is developing an innovative seasonal thermal energy storage unit for residential use. Moreover, within the project, the role of occupancy variability and use conditions in the performance of the proposed system is assessed. The present study focuses on tailor-made user-building interaction models to be implemented into dynamic simulation for the assessment of the proposed and similar systems starting from the sociological assessment of such large-scale survey results. These models take advantage from the knowledge raised by the findings of the social survey to frame for the first time occupants’ behavior scenarios representative of South, central, and North European countries. In this way, the influence of cultural context and demographic factors and their relation to heating practices are considered when developing these tailored occupant behavior models. Results show the non-negligible influence (up to 43% in the coldest climate) of implementing these models on predicted building heating energy needs, as quantitative demonstration of the role of societal-related variables on final energy use estimation.
Experiments with simulated rain on interrill plots were set up (2016–2017) at the Masse SERLAB station (42°59′34″N 12°17′27″E, Italy) to study the cumulative effects of the processes affecting the soil surface and the top 5-cm soil layer under a series of rainfalls separated by a no-rain period of several days. The modifications were quantified in terms of random roughness, bulk density (BD), porosity, and infiltration dynamics. Each experiment consists of an initial tillage and three rainfall events (intensity = 40 mm/h during wetting and 70 mm/h during runoff) in a silt-clay-loam with 51 % silt and 34 % and clay. The data confirm a quick and considerable decrease in porosity (derived through BD data). Nevertheless, the decrease is not monotonic and continuous; on the contrary, it is counteracted by an increase during the inter-rainfall period. When the porosity behavior is plotted versus applied pressure (rainfall impacts), as in oedometer tests, then it suggests a behavior on the verge of deterministic chaos with two attractors. The roughness behavior also shows a partial recovery during the between-rains intervals, confirming the BD trends. Introducing the decrease in pore size and the total porosity within a simple porous media hydraulic formula, it was possible to interpolate the infiltration data. The presence of the two BD attractors means that predictions can never be precise, unless the processes leading to the recovery of porosity are studied in detail in order to generate algorithms that evaluate the soil’s recovery behavior, which can be used in advanced infiltration models. This study underlines that adequate data are needed to generate algorithms that can evaluate the soil’s ability to recover and the total porosity between successive rainfalls.
The COVID-19 pandemic has changed people's habits, causing them to use large amounts of disposable items and exacerbating the already existing issue of pollution. One way to reduce the environmental impact of this shift in daily habits is to recycle these items, e.g. surgical masks that are the most common personal protective equipment against the virus, to produce panels for building applications. In this work, both the thermal and acoustical performance of such panels are evaluated using a small and a large scale investigation under real-world conditions. Small scale thermal tests are performed by means of the Hot Disk instrument while the acoustic investigations are performed by means of the impedance tube. Large scale tests are carried out in a reverberation chamber assessing both the heat flow passing through the wall and the acoustic absorption coefficient of the panels. Finally, the environmental impact of the innovative recycled panel is also investigated in a life cycle perspective. Overall, the material behavior scored well on these tests, suggesting that the proposed approach may be a good recycling method.
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5,357 members
Andrea Temperini
  • Department of Pharmaceutical Sciences
Erberto Carluccio
  • Department of Medicine and Surgery
Loredana Latterini
  • Department of Chemistry
Mario Mandala
  • Faculty of Medicine
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Via G. Duranti, 93, 06128, Perugia, Umbria, Italy
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Giuseppe Saccomandi
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www.ing.unipg.it
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