Lowest order stabilization free Virtual Element Method for the Poisson equation

We introduce and analyse the first order Enlarged Enhancement Virtual Element Method (E^2VEM) for the Poisson problem. The method has the interesting property of allowing the definition of bilinear forms that do not require a stabilization term. We provide a proof of well-posedness and optimal order a priori error estimates. Numerical tests on convex and non-convex polygonal meshes confirm the theoretical convergence rates

SUPG-stabilized stabilization-free VEM: a numerical investigation

We numerically investigate the possibility of defining stabilization-free Virtual Element (VEM) discretizations of advection-diffusion problems in the advection-dominated regime. To this end, we consider a SUPG stabilized formulation of the scheme. Numerical tests comparing the proposed method with standard VEM show that the lack of an additional arbitrary stabilization term, typical of VEM schemes, that adds artificial diffusion to the discrete solution, allows to better approximate boundary layers, in particular in the case of a low order scheme.Comment: 15 page

Lowest order stabilization free Virtual Element Method for the Poisson equation

We introduce and analyse the first order Enlarged Enhancement Virtual Element Method (E$^2$VEM) for the Poisson problem. The method has the interesting property of allowing the definition of bilinear forms that do not require a stabilization term. We provide a proof of well-posedness and optimal order a priori error estimates. Numerical tests on convex and non-convex polygonal meshes confirm the theoretical convergence rates.Comment: 29 pages, 6 figure

The role of natural killer cells in pancreatic ductal adenocarcinoma

Natural Killers are innate immune cells, actively involved in the detection and killing of malignant cells. Their role in pancreatic cancer is not yet understood, in part because of the paucity of infiltrative cells, compared other immune cells. Here, we have demonstrated that circulating NK cells undergo phenotypic changes, leading to functional impairment, characterised by downregulation of the main activating receptors, such as DNAM-1, NKG2D, NKp30 and NKp46. However, they retain ADCC ability and show a mature phenotype. Moreover, the analysis of the cytokines production indicates a shift to a more suppressive phenotype, highlighted by the expression of the suppressive cytokine IL-10. These changes are even more emphasized in the infiltrative compartment, with the almost complete loss of ADCC ability and the acquirement of a more “regulatory” phenotype, similar to decidual NK cells during early phases of pregnancy. Our results suggest that this could be partially induced by tumour cells, through the release of soluble form of ligands and/or the chronic cell-to-cell contact. Nevertheless, pancreatic cancer is potentially a target for NK cells’ killing activity, as demonstrated by the expression of activating ligands. In conclusion, NK cells actively participate in shaping the immune response against pancreatic cancer and they could be exploited either as a target in immune therapy and/or as biomarkers to better stratify patients, in a patient-tailored treatment settlement

A lowest order stabilization-free mixed Virtual Element Method

We initiate the design and the analysis of stabilization-free Virtual Element Methods for the laplacian problem written in mixed form. A Virtual Element version of the lowest order Raviart-Thomas Finite Element is considered. To reduce the computational costs, a suitable projection on the gradients of harmonic polynomials is employed. A complete theoretical analysis of stability and convergence is developed in the case of quadrilateral meshes. Some numerical tests highlighting the actual behaviour of the scheme are also provided

Weekend mortality in an Italian hospital: immediate versus delayed bedside critical care treatment

Background: a number of studies highlighted increased mortality associated with hospital admissions during weekends and holidays, the so-call "weekend effect". In this retrospective study of mortality in an acute care public hospital in Italy between 2009 and 2015, we compared inpatient mortality before and after a major organizational change in 2012. The new model (Model 2) implied that the intensivist was available on call from outside the hospital during nighttime, weekends, and holidays. The previous model (Model 1) ensured the presence of the intensivist coordinating a Medical Emergency Team (MET) inside the hospital 24 h a day, 7 days a week. Methods: life status at discharge after 9298 and 8223 hospital admissions that occurred during two consecutive periods of 1185 days each (organizational Model 1 and 2), respectively, were classified into "discharged alive", "deceased during nighttime-weekends-holidays" and "deceased during daytime-weekdays". We estimated Relative Risk Ratios (RRR) for the associations between the organizational model and life status at discharge using multinomial logistic regression models adjusted for demographic and case-mix indicators, and timing of admission (nighttime-weekends-holidays vs. daytime-weekdays). Results: there were 802 and 840 deaths under Models 1 and 2, respectively. Total mortality was higher for hospital admissions under Model 2 compared to Model 1. Model 2 was associated with a significantly higher risk of death during nighttime-weekends-holidays (IRR: 1.38, 95% CI 1.20-1.59) compared to daytime-weekdays (RRR: 1.12, 95% CI 0.97-1.31) (p = 0.04). Respiratory diagnoses, in particular, acute and chronic respiratory failure (ICD 9 codes 510-519) were the leading causes of the mortality excess under Model 2. Conclusions: our data suggest that the immediate availability of an intensivist coordinating a MET 24 h, 7 days a week can result in a better prognosis of in-hospital emergencies compared to delayed consultation

Comparative analysis of the thermal insulation performance of a façade enclosure integrated by vegetation under simultaneous windy and rainy climatic conditions

The literature offers some studies on the capacity of the greenery apparatus to decrease wind speed and regulate temperatures with the combination of the moisture retained by the plants and the air passing through them, but there is little on the maintenance of performance under particular weather conditions. The aim of this contri- bution is to verify the effectiveness of a vegetal façade in particularly windy conditions combined with rainy and/or high-irradiation events. The subject of the study is the enclosure of the Technology Innovation Centre for Development (itdUPM), on the Polytechnic University of Madrid, where a green wall prototype has been installed. For the purposes of the analysis, the environmental variables are examined and the monitoring data received from sensors positioned at the walls and skin of the insulated envelope are compared with the green face and without, comparing the differences in surface temperatures. These analyses are further examined by considering the correlation with different weather conditions. Experimentation shows a maintenance of per- formance, retaining an insulating capacity in all seasons, in both wind and rain, with results more evident in daylight hours. This contribute want to analyse the subtle variance between the performance of south and west facades. The strongest effect came forward during the summer season because the wall is affected by continuous irradiation on the south that is, also increased by hot weather

Association between daily levels of air pollution and school absences in the proximity of a cement plant in Italy

Background: Emission of dust represents the main hazard associated with cement production and may cause adverse respiratory health effects to the population living nearby. Aim: To evaluate the association between daily levels of PM10 and a morbidity indicator (school absenteeism) in children aged 7-14 years attending a school within 2km from a cement plant in Fumane (Northern Italy). Methods: Data on absences of students (average: 461 students/year) and daily concentrations of PM10 from a fixed monitoring station placed in the schoolyard were collected for 3 school years (541 school days from November 2007 to June 2010). The association between pollution in the same day (Lag 0) and in the previous 4 days (Lag 1 to 4) and school absenteeism was studied using generalized additive Poisson regression models, adjusting for short-term trend, day of the week, flu epidemics and daily temperature. Results: During the considered period, the daily average concentration of PM10 was 34.8 µg/m³. An increase of 10 µg/m³ of PM10 was associated with a significant increase of 2.2% in school absences (RR:1.022; 95%CI: 1.007-1.037) two days after (lag2). The association between average level of pollutants from Lag 0 to Lag 4 and school absences confirmed the presence of a statically significant association with PM10 levels (RR:1.016; 95%CI:1.003-1.029 for each + µg/m³ of PM10). Conclusions: Daily PM10 levels are associated with school absences, a proxy indicator of short-term morbidity, in children who attend schools in proximity to a cement plant. Primary prevention interventions aimed at reducing air pollution in the area are recommended