Self-induced consensus of Reddit users to characterise the GameStop short squeeze.

The short squeeze of GameStop (GME) shares in mid-January 2021 has been primarily orchestrated by retail investors of the Reddit r/wallstreetbets community. As such, it represents a paramount example of collective coordination action on social media, resulting in large-scale consensus formation and significant market impact. In this work we characterise the structure and time evolution of Reddit conversation data, showing that the occurrence and sentiment of GME-related comments (representing how much users are engaged with GME) increased significantly much before the short squeeze actually took place. Taking inspiration from these early warnings as well as evidence from previous literature, we introduce a model of opinion dynamics where user engagement can trigger a self-reinforcing mechanism leading to the emergence of consensus, which in this particular case is associated to the success of the short squeeze operation. Analytical solutions and model simulations on interaction networks of Reddit users feature a phase transition from heterogeneous to homogeneous opinions as engagement grows, which we qualitatively compare to the sudden hike of GME stock price. Although the model cannot be validated with available data, it offers a possible and minimal interpretation for the increasingly important phenomenon of self-organized collective actions taking place on social networks.

Retrograde Autologous Priming for Minimally Invasive Mitral Valve Surgery.

OBJECTIVES: Little is known about the safety and clinical utility of retrograde autologous priming (RAP) in patients undergoing minimally invasive mitral valve surgery. The study authors hypothesized that RAP would increase the oxygen delivery index (DO2i) while decreasing red blood cell transfusion requirements compared to valve surgery without RAP. DESIGN: The study was an observational analysis. SETTING: A single institutional study. PARTICIPANTS: The authors analyzed data from 500 consecutive patients who underwent minimally invasive isolated mitral valve repair from December 31, 2012, to December 31, 2019. INTERVENTION: RAP was performed in 235 patients (47%) prior to the initiation of cardiopulmonary bypass (CPB). MEASUREMENT AND MAIN RESULTS: A continuous monitoring system was used for DO2 management during CPB. The mean arterial pressure was maintained between 55 and 70 mmHg, and the cardiac index was set at 2.4 L/min/m2, with adjustments in accordance with DO2i. The trigger point for red cell blood transfusion during CPB was hemoglobin <7 g/dL. Baseline hematocrit was lower in the RAP group compared to the no-RAP group (33.4 ± 3.6 v 38.1 ± 4.9, respectively; p < 0.001). Both CPB and cross-clamp times were similar between groups. Hematocrit during CPB was significantly higher in the RAP group compared to the no-RAP group (27.6 ± 2.6 v 25.9 ± 5.1, respectively; p < 0.001). RAP was also associated with significantly higher mean DO2i (292 ± 19.5 v 282.9 ± 35.1 mL/min/m2, respectively; p < 0.001) and fewer red blood cells transfusions during the intraoperative and immediate postoperative periods (p < 0.001). CONCLUSIONS: In a minimally invasive mitral valve context, RAP was safe and associated with better DO2i, higher hematocrit, and fewer intraoperative and postoperative red blood cell transfusions.

Progress in the Development of CdTe and CdZnTe Semiconductor Radiation Detectors for Astrophysical and Medical Applications.

Over the last decade, cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) wide band gap semiconductors have attracted increasing interest as X-ray and gamma ray detectors. Among the traditional high performance spectrometers based on silicon (Si) and germanium (Ge), CdTe and CdZnTe detectors show high detection efficiency and good room temperature performance and are well suited for the development of compact and reliable detection systems. In this paper, we review the current status of research in the development of CdTe and CdZnTe detectors by a comprehensive survey on the material properties, the device characteristics, the different techniques for improving the overall detector performance and some major applications. Astrophysical and medical applications are discussed, pointing out the ongoing Italian research activities on the development of these detectors.

Tumor vascularity evaluated by transrectal color Doppler US in predicting therapy outcome for low-lying rectal cancer.

PURPOSE: To evaluate the impact on T downstaging of the vasculature supplying blood flow to rectal cancer evaluated by color Doppler ultrasound. METHODS AND MATERIALS: Color Doppler images were graded in 29 T3-staged rectal carcinoma patients sonographically just before chemoradiation. Any arterial vessels detected in rectal masses were assigned one of two grades: vascularity was considered as grade 1 for vessels feeding the periphery and as grade 2 for vessels coursing in all rectal masses within its peripheral and central portions. The pulsatility indices (PI = peak systolic velocity - end-diastolic velocity/time-averaged maximum velocity) were calculated in the central and peripheral portions. RESULTS: The pathologic observations showed a change in stage in 15 of the 23 patients graded 2, positive predictive value 65.2% (p = 0.047), and in one of the six rectal cancers graded 1 (negative predictive value, 83.3%). The minimal peripheral PI values in rectal cancer graded 2 were higher in nonresponding (2.2 +/- 1.3) than in responding lesions (1.6 +/- 0.7) p = 0.01. CONCLUSION: Vascularity graded 2 associated with low peripheral PI values are indicators of therapy outcome. Vascularity graded 1 and high peripheral PI values in graded 2 have negative predictive value.

Diagnostic imaging of the chest: exemplification of a reasoned integration.

Based on the discussion and integrated management of a case of chest radiology, the reasoned approach to the perceptive-interpretative analysis and the "reasoned" diagnostic integration is tentatively exemplified. The request of a chest X-ray from the emergency department concerned a 75-year old patient, heavy smoker and chronic alcoholic with reduced vesicular murmur, diffuse hissing sounds, basal rales, weight loss and lack of appetite. The finding of right apical nodular opacities was critically evaluated to establish its diagnostic relevance (contours, opacity, site, accessory signs). After broad-spectrum antibiotic therapy a second chest X-ray was substantially unchanged. For careful diagnostic assessment CT of the chest was performed and the definitive diagnosis of main airway obstruction, bronchiolitis and right nonspecific apical outcomes was established.

Combined diagnostic and therapeutic imaging of hemosuccus pancreaticus.

The justification of a request of ERCP in a patient with hematobilia, was evaluated, based on the medical history and negative endoscopy findings for gastrocolic bleeding. The diagnostic examination was performed: it confirmed the release of blood from the papilla of Vater, however the definitive diagnosis could not be established; CT, as the examination of first choice was performed. It provided additional information and the diagnosis of aneurysm of the splenic vein apparently non communicating with the main pancreatic duct, was established. Angiography of the splenic artery was performed as the examination of second choice to definitely ascertain the source of bleeding. During the examination, the aneurysm embolization excluded the affected vessel from the circulation and allowed immediate benefit to the patient.

Combined diagnostic imaging of transitional cell carcinoma of the upper urinary tract.

The case of a female patient with recurrent macroscopic hematuria and negative vesical and renal ultrasonography, is discussed. On urography a gross pyelocaliceal filling defect was visualized. Urographic findings were suggestive of the diagnosis of transitional cell carcinoma of the upper urinary. CT was performed to confirm the diagnosis and stage the tumor: it showed the presence of an advanced lesion. At histology the diagnosis of transitional cell carcinoma of the upper urinary tract was confirmed.