Space-time adaptive resolution for reactive flows

Multi-scale systems evolve over a wide range of temporal and spatial scales. The extent of time scales makes both theoretical and numerical analysis difficult, mostly because the time scales of interest are typically much slower than the fastest scales occurring in the system. Systems with such characteristics are usually classified as being stiff. An adaptive mesh refinement method based on the wavelet transform and the G-Scheme framework are used to achieve spatial and temporal adaptive model reduction, respectively, of physical problems described by PDEs. The combination of the methods is proposed to solve PDEs describing reaction-diffusion systems with the minimal number of degrees of freedom, for prescribed accuracies in space and time. Different reaction-diffusion systems are studied with the aim to test the performance and the capability of the combined scheme to generate accurate solutions with respect to reference ones. Several strategies are implemented to improve the performance of the scheme, with minimal loss of accuracy

Fenomenologia dei social network. Presenza, relazioni e consumi mediali degli italiani online

Cosa spinge ogni giorno milioni di persone a utilizzare i social network e a considerarli uno spazio oramai dato per scontato della propria vita quotidiana? Perché molti temi caldi del recente dibattito pubblico ruotano attorno alla vita online – dal narcisismo digitale alla perdita della privacy – e al suo rapporto di continuità con quella offline? Nel rispondere a queste domande, il libro si spinge alle radici della realtà dei social network, per interrogare condizioni di possibilità e pratiche sociali che hanno permesso ad ambienti comunicativi come Facebook di diventare un orizzonte diffuso di senso individuale e collettivo e un luogo di osservazione privilegiato dell’importanza che i media e il Web hanno nella nostra vita. Attraverso i racconti degli utenti raccolti nell’ambito di un progetto di ricerca nazionale, il lavoro indaga in che modo Facebook sia diventato una palestra sociale in cui gli intrecci tra pratiche d’uso, forme di consumo e affordance della piattaforma mettono in luce sia le dinamiche di socializzazione all’inclusione comunicativa, sia la costante ricerca di senso della e nella connessione

Fenomenologia dei social network. Presenza, relazioni e consumi mediali degli italiani online

Cosa spinge ogni giorno milioni di persone a utilizzare i social network e a considerarli uno spazio oramai dato per scontato della propria vita quotidiana? Perché molti temi caldi del recente dibattito pubblico ruotano attorno alla vita online – dal narcisismo digitale alla perdita della privacy – e al suo rapporto di continuità con quella offline? Nel rispondere a queste domande, il libro si spinge alle radici della realtà dei social network, per interrogare condizioni di possibilità e pratiche sociali che hanno permesso ad ambienti comunicativi come Facebook di diventare un orizzonte diffuso di senso individuale e collettivo e un luogo di osservazione privilegiato dell’importanza che i media e il Web hanno nella nostra vita. Attraverso i racconti degli utenti raccolti nell’ambito di un progetto di ricerca nazionale, il lavoro indaga in che modo Facebook sia diventato una palestra sociale in cui gli intrecci tra pratiche d’uso, forme di consumo e affordance della piattaforma mettono in luce sia le dinamiche di socializzazione all’inclusione comunicativa, sia la costante ricerca di senso della e nella connessione

Relazioni sociali e identità in rete: vissuti e narrazioni degli italiani su Facebook

Il paper presenta i risultati di una ricerca di interesse nazionale (PRIN) finanziata dal Ministero della Ricerca e dell’Università dal titolo Relazioni sociali ed identità in Rete: vissuti e narrazioni degli italiani su Facebook. La ricerca mira ad indagare le forme di costruzione e ridefinizione delle relazioni sociali e dell’identità degli italiani in Rete, concentrandosi in particolare sulle pratiche e i significati che gli utenti forniscono al loro stare su un Social Network come Facebook. Su questa base, la domanda di ricerca può essere formulata in questi termini: qual è il vissuto comunicativo degli italiani su Facebook? In altre parole, se con vissuto intendiamo il frame che incornicia l’esperienza e la rende comunicabile e condivisibile con gli altri, quali sono le dinamiche di senso attraverso le quali l’utente produce e racconta ciò che egli stesso pensa di esser su Facebook? Questa domanda non può che essere legata all’ipotesi generale secondo cui Facebook è un contesto non anonimo che presenta forti livelli di ancoraggio con la realtà offline (Zhao, Grasmuck, Martin 2008) in cui gli utenti adottano comportamenti comunicativi riflessivamente orientati alla presentazione di sé e alla gestione delle proprie reti sociali in termini di pubblico/audience

The Diagnostic Performance of Multi-Detector Computed Tomography (MDCT) in Depiction of Acute Spondylodiscitis in an Emergency Department

Background: The diagnosis of acute spondylodiscitis can be very difficult because clinical onset symptoms are highly variable. The reference examination is MRI, but very often the first diagnostic investigation performed is CT, given its high availability in the acute setting. CT allows rapid evaluation of other alternative diagnoses (e.g., fractures), but scarce literature is available to evaluate the accuracy of CT, and in particular of multi-detector computed tomography (MDCT), in the diagnosis of suspected spondylodiscitis. The aim of our study was to establish MDCT accuracy and how this diagnostic method could help doctors in the depiction of acute spondylodiscitis in an emergency situation by comparing the diagnostic performance of MDCT with MRI, which is the gold standard. Methods: We searched our radiological archive for all MRI examinations of patients who had been studied for a suspicion of acute spondylodiscitis in the period between January 2017 and January 2021 (n = 162). We included only patients who had undergone MDCT examination prior to MRI examination (n = 25). The overall diagnostic value of MDCT was estimated, using MRI as the gold standard. In particular, the aim of our study was to clarify the effectiveness of CT in radiological cases that require immediate intervention (stage of complications). Therefore, the radiologist, faced with a negative CT finding, can suggest an elective (not urgent) MRI with relative serenity and without therapeutic delays. Results: MDCT allowed identification of the presence of acute spondylodiscitis in 13 of 25 patients. Specificity and positive predictive value were 100% for MDCT, while sensitivity and negative predictive value were 68% and 50%, respectively, achieving an overall accuracy of 76%. In addition, MDCT allowed the identification of paravertebral abscesses (92%), fairly pathognomonic lesions of spondylodiscitis pathology. Conclusions: The MDCT allows identification of the presence of acute spondylodiscitis in the Emergency Department (ED) with a satisfactory accuracy. In the case of a positive CT examination, this allows therapy to be started immediately and reduces complications. However, we suggest performing an elective MRI examination in negative cases in which pathological findings are hard to diagnose with CT alone

Minimally invasive surgery for gastric cancer: A comparison between robotic, laparoscopic and open surgery

IF 3.365International audienceAIMTo investigate the role of minimally invasive surgery for gastric cancer and determine surgical, clinical, and oncological outcomes.METHODSThis is a propensity score-matched case-control study, comparing three treatment arms: robotic gastrectomy (RG), laparoscopic gastrectomy (LG), open gastrectomy (OG). Data collection started after sharing a specific study protocol. Data were recorded through a tailored and protected web-based system. Primary outcomes: harvested lymph nodes, estimated blood loss, hospital stay, complications rate. Among the secondary outcomes, there are: operative time, R0 resections, POD of mobilization, POD of starting liquid diet and soft solid diet. The analysis includes the evaluation of type and grade of postoperative complications. Detailed information of anastomotic leakages is also provided.RESULTSThe present analysis was carried out of 1026 gastrectomies. To guarantee homogenous distribution of cases, patients in the RG, LG and OG groups were 1: 1: 2 matched using a propensity score analysis with a caliper = 0.2. The successful matching resulted in a total sample of 604 patients (RG = 151; LG = 151; OG = 302). The three groups showed no differences in all baseline patients characteristics, type of surgery (P = 0.42) and stage of the disease (P = 0.16). Intraoperative blood loss was significantly lower in the LG (95.93 +/- 119.22) and RG (117.91 +/- 68.11) groups compared to the OG (127.26 +/- 79.50, P = 0.002). The mean number of retrieved lymph nodes was similar between the RG (27.78 +/- 11.45), LG (24.58 +/- 13.56) and OG (25.82 +/- 12.07) approach. A benefit in favor of the minimally invasive approaches was found in the length of hospital stay (P < 0.0001). A similar complications rate was found (P = 0.13). The leakage rate was not different (P = 0.78) between groups.CONCLUSIONLaparoscopic and robotic surgery can be safely performed and proposed as possible alternative to open surgery. The main highlighted benefit is a faster postoperative functional recovery

Minimally invasive surgery for gastric cancer: A comparison between robotic, laparoscopic and open surgery.

AimTo investigate the role of minimally invasive surgery for gastric cancer and determine surgical, clinical, and oncological outcomes.MethodsThis is a propensity score-matched case-control study, comparing three treatment arms: robotic gastrectomy (RG), laparoscopic gastrectomy (LG), open gastrectomy (OG). Data collection started after sharing a specific study protocol. Data were recorded through a tailored and protected web-based system. Primary outcomes: harvested lymph nodes, estimated blood loss, hospital stay, complications rate. Among the secondary outcomes, there are: operative time, R0 resections, POD of mobilization, POD of starting liquid diet and soft solid diet. The analysis includes the evaluation of type and grade of postoperative complications. Detailed information of anastomotic leakages is also provided.ResultsThe present analysis was carried out of 1026 gastrectomies. To guarantee homogenous distribution of cases, patients in the RG, LG and OG groups were 1:1:2 matched using a propensity score analysis with a caliper = 0.2. The successful matching resulted in a total sample of 604 patients (RG = 151; LG = 151; OG = 302). The three groups showed no differences in all baseline patients characteristics, type of surgery (P = 0.42) and stage of the disease (P = 0.16). Intraoperative blood loss was significantly lower in the LG (95.93 ± 119.22) and RG (117.91 ± 68.11) groups compared to the OG (127.26 ± 79.50, P = 0.002). The mean number of retrieved lymph nodes was similar between the RG (27.78 ± 11.45), LG (24.58 ± 13.56) and OG (25.82 ± 12.07) approach. A benefit in favor of the minimally invasive approaches was found in the length of hospital stay (P &lt; 0.0001). A similar complications rate was found (P = 0.13). The leakage rate was not different (P = 0.78) between groups.ConclusionLaparoscopic and robotic surgery can be safely performed and proposed as possible alternative to open surgery. The main highlighted benefit is a faster postoperative functional recovery