204 research outputs found
Charting the phase diagram of QCD3
We study the phase diagram of SU (N) gauge theory in three space-time dimensions with a Chern-Simons term at level k, coupled to two sets of fundamental fermions with masses m1 and m2, respectively. The two-dimensional phase diagram that we propose shows a rich structure and widens in an interesting way previous results in the literature, to which it reduces in some limits. We present several checks of our proposal, including consistency with boson/fermion dualities. In this respect, we extensively comment on the structure of the scalar potential which is needed on the bosonic side of the duality
Simulation of the December 2017 Flood on the Enza River using a 2D SWE code Coupled with a Levee Breach Erosion Model
The levee breach that occurred on the Enza River (Italy) on December 12th 2017 and the resulting flood are simulated with a GPU-accelerated 2D SWE code, where a simple erosion model was implemented to describe the breach evolution in detail
2-D numerical modeling of rapidly varying shallow water flows by Smoothed Particle Hydrodynamics technique
River engineeringNumerical modelling in river engineerin
Flood inundation modeling in urbanized areas: A mesh-independent porosity approach with anisotropic friction
In the present work, a porosity-based numerical scheme for the Shallow Water Equations is presented. With the aim of accounting for the presence of storage areas, such as gardens, yards and dead zones, and for preferential flow pathways, both an isotropic storage porosity parameter and anisotropic friction are adopted. Particularly, the anisotropic effects due to the building alignments are evaluated defining conveyance porosities along principal directions and using them to express the friction losses in tensor form. The storage and conveyance porosities are evaluated from the geometry of the urban layout at a district scale and then assigned to computational cells rather than to cell sides, thus avoiding oversensitivity to the mesh design. The proposed formulation guarantees the C-property also in presence of wet-dry fronts. Model testing is performed analyzing schematic and idealized urban layouts, and against experimental data as well. The results obtained by the proposed anisotropic scheme are similar to a high-resolution model with resolved buildings, also in the presence of low-friction regimes, meanwhile with a remarkable reduction of the computational times
Sutureless and rapid deployment implantation in bicuspid aortic valve: results from the sutureless and rapid-deployment aortic valve replacement international registry.
Background
Benefits of sutureless and rapid deployment (SURD) bioprostheses in bicuspid aortic valves (BAV) are controversial. The aim of this study is to report the outcomes of patients undergoing aortic valve replacement (AVR) for BAV from the Sutureless and Rapid-Deployment Aortic Valve Replacement International Registry (SURD-IR).
Methods
Of the 4,636 patients who received primary isolated SURD-AVR between 2007 and 2018, 191 (4.1%) BAV patients underwent AVR with SURD valve.
Results
Overall 30-day mortality was 1.6%. The Intuity valve was implanted in 53.9% of cases, whereas the Perceval was implanted in 46.1%. Rate of stroke for isolated AVR was 4.2%. No case of endocarditis, thromboembolism, myocardial infarction, valve dislocation or structural valve deterioration was reported in the early phase. Rate of pacemaker implantation and moderate-severe aortic regurgitation (AR) were 7.9% and 3.7%, respectively.
Conclusions
BAV is not considered a contraindication for the implantation of SURD valves. However, detailed information of aortic root geometry as well as the knowledge of some technical considerations are mandatory for a good outcome
Sutureless Versus Rapid Deployment Aortic Valve Replacement: Results From a Multicenter Registry
BACKGROUND This study compared clinical and hemodynamic in-hospital outcomes of patients undergoing suture -less vs rapid deployment aortic valve replacement (SURD-AVR) in the large population of the Sutureless and Rapid Deployment International Registry (SURD-IR). METHODS We examined 4695 patients who underwent isolated or combined SURD-AVR. The "sutureless" Perceval valve (LivaNova PLC, London, United Kingdom) was used in 3133 patients and the "rapid deployment" Intuity (Edwards Life -sciences, Irvine, CA) in 1562. Potential confounding factors were addressed by the use of propensity score matching. After matching, 2 well-balanced cohorts of 823 pairs (isolated SURD-AVR) and 467 pairs (combined SURD-AVR) were created. RESULTS Patients who received Perceval and Intuity valves showed similar in-hospital mortality and rate of major post-operative complications. Perceval was associated shorter cross-clamp and cardiopulmonary bypass times. In the isolated SURD-AVR group, patients receiving Perceval were more likely to undergo anterior right thoracotomy incision. Postoperative transvalvular gradients were significantly lower for the Intuity valve compared with those of the Perceval valve, either in isolated and combined SURD-AVR. The Intuity valve was associated with a lower rate of postoperative mild aortic regurgitation. CONCLUSIONS Our results confirm the safety and efficacy of SURD-AVR regardless of the valve type. The Perceval valve was associated with reduced operative times and increased anterior right thoracotomy incision. The Intuity valve showed superior hemodynamic outcomes and a lower incidence of postoperative mild aortic regurgitation. (Ann Thorac Surg 2022;114:758-66) (c) 2022 by The Society of Thoracic Surgeon
Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.
BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24 months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500 steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30 minutes spent performing activities â„500 counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24 months), both the number of steps per day (per 500 steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity â„500 counts per minute (per 30 minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score >10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500
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