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to provide information on long-term outcomes of Heller myotomy for esophageal achalasia with or without an antireflux fundoplication.Since the adoption of the Heller myotomy, surgeons have modified the original technique in order to balance the cure of dysphagia and the consequent cardial incontinence.470 patients underwent primary Heller myotomy between 1955 and 2020. A long abdominal myotomy (AM) was performed in 83 patients, the Ellis limited transthoracic myotomy (TM) in 30, the laparotomic Heller-Dor (L-HD) in 202, the videolaparoscopic Heller-Dor (VL-HD) in 155. The HD was performed under intraoperative manometric assessment. Starting on 1973 these patients underwent a prospective follow-up program of timed lifelong clinical, radiological, endoscopic evaluations.Median follow-up time was 23.06 years (IQR 15.04-32.06) for AM, 29.22 years (IQR 13.46-40.17) for TM, 14.85 years (IQR 11.05-21.56) for L-HD and 7.51 years (IQR 3.25-9.60) for VL-HD. In AM, relapse of dysphagia occurred in 25/71 (35.21%), in TM in 11/30 (36.66%), in LH-D in 10/201 (4.97%), in VL-HD in 3/155 (1.93%). Erosive-ulcerative esophagitis was diagnosed for AM in 28.16%, for TM in 30%, for L-HD in 8.45%, for VL-HD in 2.58%. Overall, the outcome was satisfactory in 52.11% for AM, 41.9% for TM, 89.05% for L-HD, 96.12% for VL-HD.The Dor fundoplication drastically reduces post myotomy gastro-esophageal reflux. The Heller-Dor operation is a competitive option for the cure of esophageal achalasia if this operation is performed according to the rules of surgical physiology learned by means of intraoperative manometry.

The outcome of achalasia treatment in patients with sigmoid esophagus is worse than that achieved for fusiform achalasia. We compared two groups of sigmoid achalasia patients, in which we performed the standard Heller-Dor procedure (HD) and the Heller-Dor plus a technique aimed to restore the vertical axis of the intraabdominal portion of the esophagus pull-down Heller-Dor (PD-HD). Long-term results were evaluated. We considered 48 patients affected by primitive esophageal sigmoid achalasia operated upon consecutively (1979-2021) in first instance. After 1987, we routinely isolated 360° of the gastro-esophageal junction and the lower esophagus and applied U stitches at the right side of the lower esophagus to pull down and rotate the gastro-esophageal junction toward the right. Twenty-five patients underwent the standard HD and 23 patients underwent the PD-HD technique. Postoperative follow-up included barium swallow, clinical interview investigating dysphagia and reflux symptoms and endoscopy. The overall outcome was graded from excellent to poor according to the severity of symptoms and esophagitis. The median follow-up period was 11 years (IQR 6-22) for HD group and 9 (IQR 6-14) for PD-HD (p=0.22). At postoperative barium swallow, patients in the PD-DH group had smaller esophageal diameter [4 cm (IQR 4-4.7) vs 4.7 cm (IQR 4-5), p=0.04] and lower residual barium column [10 cm (IQR 6-13) vs 6 cm (IQR 0-8), p=0.001] than those in the HD group. Postoperative moderate-severe (D2-D3) dysphagia rates were 40% for HD and 13% for PD-HD group (p=0.003). The outcome of treatment revealed satisfactory (excellent, good, fair) results in 68% and 91.4% of HD and PD-HD group patients, respectively. The Heller-Dor operation is effective in the presence of sigmoid achalasia. The clinical and instrumental evaluations showed better results with the PD-HD technique. This technique may be the first choice for end-stage achalasia with null or low risk for cancer.

Prevalence and surgical treatment of true short esophagus (TSE), defined as the intra operative position of the apex of the gastric folds (endoscopic cardia- EC) The distance between the endoscopically-localized EC marked with clips by the surgeon and the apex of the diaphragmatic hiatus after maximal thoracic esophagus mobilization was measured during the laparoscopic procedure. A standard Nissen fundoplication (SN) was performed in cases with an abdominal length >1.5 cm; in cases of TSE a laparoscopic-thoracoscopic Collis-Nissen (CN) or laparoscopic Stomach Around Stomach Fundoplication (SASF) in elderly patients was performed. The fundoplication superior margin was always fixed below the hiatus, over the EC. Patients’ symptoms, radiological and endoscopic data were pre/postoperatively recorded. After intra-thoracic esophageal mobilization (median =9 cm), TSE was diagnosed in 30.38 % of 441 cases (31,8% in 311/2004-2017; 27,7% in 130/2017-2022). SN was performed in 69%, CN in 23% and SASF in 7%. On 441 cases regularly followed up with a median of 106 months, HH relapse was radiologically diagnosed in 3%, with excellent, good, fair, and poor outcomes respectively in 46.3%, 43.2%, 6.7%, and 3.8% of cases. No outcome significant differences among SN CN and SASF, were recorded. In the period 2004-2022, prevalence of TSE was constant in a significant third of patients routinely submitted to GERD/HH surgery. In the presence of TSE, CN and SASF performed according to determined surgical principles may achieve results as satisfactory as those obtained with SN.

Literature supporting the adoption of POEM in place of the standard Heller myotomy in the presence of significant chest pain associated with typical symptoms like in case of Achalasia Type III according to the Chicago classification, generally reports on outcome data collected after short follow up periods. We aimed to assess behaviors of chest pain in the long term in a case series of patients submitted to the Heller-Dor operation. Between 1978 and 2021,394 achalasia patients underwent the Heller-Dor operation. Chest pain was evaluated according to its frequency (0: absent; 1: occasional; 2: weekly; 3: daily): 81 preoperatively complained of chest pain (score 2-3) (CP group), 313 did not (score 0-1) (NCP group). Patients were followed up according to a timed protocol based on clinical assessment of dysphagia (D0 absent – D3 each meal), GERD symptoms (RS0 absent-RS3 each meal). Barium swallow and endoscopy (E0: normal, E1: mild esophagitis, E2-3: erosive/ulcerative esophagitis) were performed at each planned control. CP and NCP were compared. CP group had shorter duration of dysphagia (p=0.03), smaller esophageal diameter and lower barium column (p According to our single center case series, in the long term chest pain does not influence negatively HD outcome which is absolutely competitive with that generally reported for POEM and pneumatic dilation. Results presented in this study must be verified: as new randomized prospective studies would require a too long lag time, valid retrospective multi center studies should be performed.

Recently, it was reported that the Bladder EpiCheck test is likely to represent a valid tool in the diagnostic process of patients who have suspected bladder carcinoma, with some controversial management decisions because of the technical limitations of cytology.Two hundred ninety patients with a diagnosis of nonmuscle-invasive bladder carcinoma who were admitted at the authors' department from March 2019 to December 2019 were treated and followed for 1 year. During follow-up, all patients were evaluated by voided urine cytology, white-light cystoscopy (according to European Association of Urology guidelines), and the Bladder EpiCheck test.The cytologic diagnoses of high-grade urothelial carcinoma (HGUC) and suspicious for HGUC were histologically confirmed in 5 of 20 patients (25%) who had quantitative Bladder EpiCheck scores (EpiScores) from 60 to 69, in 23 of 36 patients (64%) who had EpiScores from 70 to 79, and in 42 of 56 patients (75%) and 57 of 63 patients (90%) who had EpiScores between 80 and 89 and EpiScores90, respectively. Of 48 patients who had a cytologic diagnosis of HGUC or suspicious for HGUC with EpiScores ≥60 and negative histology, 20 (42%) had a recurrence of HGUC, which was cytologically and histologically confirmed, at 6-12 months during follow-up.To the best of the authors' knowledge, this is the first study in which patients at high risk for HGUC were stratified using the Bladder EpiCheck EpiScore. The results validate this methylation analysis tool as a useful method for predicting recurrent HGUC during the follow-up of patients with nonmuscle-invasive bladder carcinoma.

This paper presents an approach to mesh adaptation suitable for scale-resolving simulations. The methodology is based on the entropy-adjoint approach, which corresponds to a standard output-based a...

In recent years Computational Fluid Dynamics (CFD) has become a widespread practice in industry. The growing need to simulate off-design conditions, characterized by massively separated flows, strongly promoted research on models and methods to improve the computational efficiency and to bring the practice of Scale Resolving Simulations (SRS), like the Large Eddy Simulation (LES), to an industrial level. Among the possible approaches to the SRS, an appealing choice is to perform Implicit LES (ILES) via a high-order Discontinuous Galerkin (DG) method, where the favourable numerical dissipation of the space discretization scheme plays directly the role of a subgrid-scale model. To reduce the large CPU time for ILES, implicit time integrators, that allows for larger time steps than explicit schemes, can be considered. The main drawbacks of implicit time integration in a DG framework are represented by the large memory footprint, the large CPU time for the operator assembly and the difficulty to design highly scalable preconditioners for the linear solvers. In this paper, which aims to significantly reduce the memory requirement and CPU time without spoiling the high-order accuracy of the method, we rely on a p-adaptive algorithm suited for the ILES of turbulent flows and an efficient matrix-free iterative linear solver based on a cheap p-multigrid preconditioner and a Flexible GMRES method. The performance and accuracy of the method have been assessed by considering the following test cases: (1) the T3L test case of the ERCOFTAC suite, a rounded leading edge flat plate at $${\mathrm{Re}}_D=3450$$ ; (2) the flow past a sphere at $$\mathrm{Re}_D=300$$ ; (3) the flow past a circular cylinder at $$\mathrm{Re}_D=3900$$ .

Purpose To prospectively evaluate the survival at 1 and 4 years of short implants retaining removable partial dentures (RPDs) in Kennedy Class I and II edentulism. Materials and methods Twenty patients (Kennedy Class I and II) rehabilitated with RPDs were selected for the insertion of one short implant in the distal edentulous ridge, connected to the RPD with a Locator attachment after osseointegration. The following data were recorded at the 1- and 4-year follow-up: bone loss, bleeding on probing (BOP), probing depth (PD), implant mobility, and survival. Results Thirty-five implants were placed from September 2012 to April 2014. At the 4-year follow-up, 12 implants showed BOP, and for PD, 15 implants showed 2 mm, 16 implants showed 3 mm, and 2 implants showed 4 mm. One implant showed mobility, and two were lost (survival rate: 94.3%; 95% CI: 80.84 to 99.30). The mean bone loss was 1.04 ± 1.88 mm. Conclusion Within the limitations of this study, the implant survival rate and the mean bone loss values reported are comparable with those reported by other authors. The use of short implants for retaining RPDs may be considered a viable treatment option for patients with distal edentulism and contraindications for more complex implant rehabilitation.

The management of non-muscle invasive bladder carcinoma (NMIBC) after transurethral resection of a bladder tumor consists of adjuvant intravesical therapy and strict and long surveillance with urine cytology and cystoscopy. The Bladder EpiCheck test (Nucleix Ltd) (BE) is a newly developed urinary markers based on DNA methylation changes in a panel of 15 genomic biomarkers, with a promising performance in term of non-invasive NMIBC detection.In this study we prospectively enrolled 151 consecutive patients with high grade NMIBC, treated with intravesical BCG and mitomycin C therapy and evaluated during the follow-up by voided urine cytology and white-light cystoscopy, according to the European Association of Urology Guidelines. The Bladder EpiCheck test was performed at the same time of urine cytology in voided specimen. In all cases with positive cytology the diagnosis was confirmed by histology and a diagnosis was made according to the 2017 tumor, node, metastasis (TNM) classification and graded using both the 1973 and the 2004 World Health Organization (WHO) classifications.At three months of follow-up, we reported similar overall specificity rates for BE and urine cytology (85,1% vs 86,3%). In the group of patients with carcinoma in situ (CIS), we found the same specificity for BE and urine cytology (81,4%), while in the groups of patients with papillary high grade NMIBC, the specificity of BE was higher compared to cytology (96,3% vs 90,4%). The sensitivity of BE was always higher compared to cytology during all the follow-up both for papillary NMIBC and CIS.In the early follow-up of NMIBC the EpiCheck test might replace urinary cytology.

In recent years the use of high-order Discontinuous Galerkin (DG) methods for the under-resolved direct numerical simulations (uDNS) of turbulent flows has received special attention. The suitability of the approach for this kind of applications is related to the dissipation and dispersion proprieties of the scheme: while the dispersion errors are small over a broad range of frequencies, a relevant dissipation error mainly acts at the smallest under-resolved scales, resembling a high frequency filter. Nevertheless, it was recognized (Flad and Gassner, 2017; Mengaldo et al., 2018) that the choice of the interface convective numerical flux strongly affects this dissipation behaviour and ultimately the success of the uDNS approach. In this regard, the excess of numerical dissipation caused by some upwind numerical convective fluxes must be avoided, in particular when dealing with low-speed flows, since this behaviour is exacerbated approaching the incompressibility limit. Fixes for the excess of numerical dissipation of these schemes have been proposed by several authors in the context of different numerical methods, see for example Weiss and Smith (1995). In this work a simple modification of the dissipation term of the low Mach preconditioned Roe scheme proposed by Weiss and Smith is considered. The aim is to reduce further the amount of numerical dissipation with the intent of improving the results of uDNS. A spatial DG discretization coupled with a linearly-implicit Rosenbrock-type time integrator is here considered as a numerical framework perfectly suited for the assessment and comparison of different numerical flux functions. Results on canonical turbulent flow problems as the Taylor–Green vortex and the flow in a straight sided channel are presented. The improved accuracy of the proposed flux function is demonstrated. The new low-dissipation flux can be useful also in the context of standard, lower order, finite volume methods.

This chapter describes space adaptive approaches developed by six TILDA partners for the application in scale-resolving simulations. They are designed to provide sufficient spatial resolution in regions where required and to allow a lower resolution elsewhere for efficiency reasons. Adaptation techniques considered include mesh (h-refinement), order refinement of the spatial discretization (p-refinement) or a combination of both (hp-refinement). Furthermore, near-wall local mesh refinement, refinement using feature-based indicators and indicators obtained from the Variational Multiscale Method are considered., Series: Notes on Numerical Fluid Mechanics and Multidisciplinary Design

This chapter includes computational details and results obtained in the EU-project TILDA on the Boeing Rudimentary Landing Gear.

The present work deals with the development of an original Discontinuous Galerkin (DG) finite element code and its application to compute the non-reactive aerodynamics of multicomponent gaseous mixtures in turbulent regime. Recent developments of the DG approach show great potential in computing high-order accurate solutions on arbitrarily complex grids even in the presence of strong discontinuities and thus the method is well suited for modeling combustion aerodynamics. The study of coaxial jets, with and without swirl, is indeed of paramount importance in assessing burner and combustor performance and the accurate understanding of their fluid dynamic behaviour is an essential prerequisite to subsequently investigate their reactive counterpart. The predictive capabilities of the novel method proposed are verified against several experimental tests taken from three different databases, selected to cover the widest range of coaxial jets operating conditions, and compared with simulations carried out using a commercial code, at most second-order accurate. Notwithstanding the numerical prediction of turbulent gaseous mixture is indeed challenging, it is shown that the DG method exhibits a good accuracy level even on coarse grids and allows to properly resolve the relevant jet structures and characteristic features.

This chapter describes the approaches to wall-modeled LES proposed by three TILDA Partners. DLR adopts a classic treatment of the near wall region with wall functions. University of Bergamo and Dassault Aviation rely on hybridization of LES with a RANS model near the wall. University of Bergamo relies on the switch of X-LES and Dassault Aviation adopts a DDES methodology coupled with their VMS.

The NASA Rotor 37 is an isolated transonic axial compressor rotor. This case was initially included in a wider research program to cover a range of design parameters typical of high pressure compressor inlet stage of aircraft engines. Most numerical studies fail at predicting with accuracy the overall performance, e.g., the adiabatic efficiency and the losses distribution downstream of the blade. This case presents indeed several phenomena which are challenging to capture: laminar-to-turbulent transition on the blade, interaction of the boundary layer with the shock, secondary and tip-leakage flows. If LES appears a more adequate tool than RANS to predict such inherently unsteady phenomena, it remains delicate, especially because wall modeling is required. This section presents results obtained by Safran and UniBG of WMLES using the Discontinuous Galerkin approach.

While the exascale computing era is approaching, the growing gap between computing resources and IO bandwidth for massively parallel simulations has already become a major bottleneck for the scientific discovery process. In this context, various strategies to enable and accelerate the analysis of data produced by massively parallel high-order methods are presented, with an emphasis on in-situ visualization and co-processing techniques. First, a library of parallel procedures is presented for an efficient collection of turbulence statistics within the framework of a modal discontinuous Galerkin method. Afterwards, an acoustic co-processing strategy is presented whereby sound radiation calculations are performed concurrently with CFD calculations in order to avoid the need to store prohibitive amount of data. Finally, an open-source and scalable post-hoc visualization and processing tool dedicated to the analysis of large data sets produced by high order methods is first presented. This post-hoc processing tool has then been extended to a co-processing interface which enables live in-situ visualization and analysis of high-order solutions produced by massively parallel simulations.

Objective: To explore the true short esophagus (TSE) frequency and longterm results of patients undergoing gastro-esophageal reflux disease (GERD) or hiatus hernia (HH) surgery. Background: The existence and treatment of TSE during GERD/HH surgery is controversial. Satisfactory long-term results have been achieved with and without surgical techniques dedicated to TSE. Methods: In 311 consecutive patients undergoing minimally invasive surgery for GERD/HH, the distance between the endoscopically-localized gastroesophageal junction (GEJ) and the apex of the diaphragmatic hiatus after maximal thoracic esophagus mobilization was measured. A standard Nissen fundoplication (SN) was performed in cases with an abdominal length >1.5 cm; in cases of TSE (abdominal length

In this Section a detailed and quantitative understanding is provided of how algorithms should be designed and implemented to effectively target a range of existing and emerging ‘massively parallel’ hardware platforms. The goal set up in the TILDA project was to demonstrate the capability and efficiency of the high-order methods developed by the partners on up to 50,000 cores.

In recent years, the interest for composite RANS-LES models, wall-modelled LES approaches and their application to the high-fidelity simulation of turbulent flows has been growing rapidly. This interest is motivated by the need to overcome the well known limitations of RANS models in simulating massively separated flows and to mitigate the cost of a full LES, which nowadays can be still not feasible for many industrial applications.

In this work we present a high-order discontinuous Galerkin approach for the simulation of variable density incompressible (VDI) flows. Here, the density is treated as a purely advected property tracking possibly multiple (more than two) components, while the fluids interface is captured in a diffuse fashion by the high-degree polynomial solution thus not requiring any geometrical reconstruction. Specific care is devoted to deal with density over/undershoots, spurious oscillations at flows interfaces and Godunov numerical fluxes at inter-element boundaries. Time integration is performed with high-order implicit schemes thus preventing any time step restriction condition. Promising results with high-degree polynomial representation and relatively coarse meshes are achieved on numerical experiments involving high-density ratios (water–air) and the possible interaction of more than two components.

In this work we present a novel exact Riemann solver for an artificial Equation of State (EoS) based modification of the incompressible Euler equations. Differently from the well known artificial compressibility method, this new approach overcomes the lack of the pressure-velocity coupling by using a suitably designed artificial EoS. The modified set of equations fits into the framework of first order hyperbolic conservation laws. Accordingly, an exact Riemann solver is derived. This new solver has the advantage to avoid a wave pattern violation issue which can affect the exact Riemann problem solution obtained by the standard artificial compressibility approach. The new artificial EoS based Riemann solver can be used as a tool for the definition of the advective Godunov fluxes in a Finite Volume or a discontinuous Galerkin discretization of the incompressible Navier–Stokes (INS) equations. We assess and analyse the new exact Riemann solver on 1D Riemann problems. Its capability and effectiveness are then shown in the context of a high-order accurate discontinuous Galerkin discretization of the INS equations. In particular, we verify the convergence properties, both in space and time, considering two test cases in 2D, namely, the Kovasznay test case and a damped travelling waves test case. Finally, we perform an implicit large eddy simulation of the incompressible turbulent flow over periodic hills where the classic forcing term formulation is modified to deal with variable time steps. Solution comparisons with respect to numerical and experimental results from the literature are given.

In this work we present and compare three Riemann solvers for the artificial compressibility perturbation of the 1D variable density incompressible Euler equations. The goal is to devise an artificial compressibility flux formulation to be used in Finite Volume or discontinuous Galerkin discretizations of the variable density incompressible Navier–Stokes equations. Starting from the constant density case, two Riemann solvers taking into account density jumps at fluid interfaces are first proposed. By enforcing the divergence free constraint in the continuity equation, these approximate Riemann solvers deal with density as a purely advected quantity. Secondly, by retaining the conservative form of the continuity equation, the exact Riemann solver is derived. The variable density solution is fully coupled with velocity and pressure unknowns. The Riemann solvers are compared and analysed in terms of robustness on harsh 1D Riemann problems. The extension to multidimensional problems is described. The effectiveness of the exact Riemann solver is demonstrated in the context of an high-order accurate discontinuous Galerkin discretization of variable density incompressible flow problems. We numerically validate the implementation considering the Kovasznay test case and the Rayleigh–Taylor instability problem.

Purpose To verify whether single-implant-supported mandibular overdentures improve thickness discrimination. Materials and methods A selection of edentulous patients treated with single-implant-supported overdentures underwent interocclusal thickness discrimination tests using dedicated metal strips. Fifteen patients were included, and recordings were repeated five times: with complete dentures in place before placement of implants, the day of the prosthetic connection, and 1 month, 1 year, and 6 years after the connection. Results and conclusion Thickness discrimination improved at the 1-month recall recording, while after 1 year, it remained stable at low levels.

This paper aims to report on the open multi-processing (OpenMP) parallel implementation of a fully unstructured high-order discontinuous Galerkin (DG) solver for computational fluid dynamics and computational aeroacoustics applications. Even if the use of OpenMP paradigm is confined to shared memory systems, it has some advantages over the use of the message passing interface (MPI) library, and getting the best of this approach potentially improves the parallel efficiency of codes running on clusters of multi-core nodes. While with MPI the use of a domain decomposition algorithm is almost unavoidable, the OpenMP shared memory context offers several opportunities. Three strategies, here optimised for a DG solver, are presented and compared: the first refers to a customization of a colouring approach, the second mimics an MPI implementation in the OpenMP context, while the third method is somehow half way between the previous two. The numerical tests performed on both inviscid and viscous test cases indicate that, thanks to the compactness of the DG discretization, all the code versions perform quite satisfactory. In particular, the domain decomposition algorithm reaches the highest level of parallel efficiency at low computational loads while the colouring approach excels at larger computational loads and it can be easily implemented within an existing MPI code. Moreover, colouring is very well suited to deal with hardware accelerators, an opportunity given by the OpenMP 4.0 standard. Finally, the performance gain observed in using a hybrid MPI/OpenMP version of the DG code on high performance computing facilities is demonstrated.

Recent years have seen an ever-increasing interest in turbulence models able to go beyond the limited predictive capability of the Reynolds-averaged Navier–Stokes (RANS) formulation. In the range of moderate Reynolds numbers, availability of large HPC resources now allows to employ Large Eddy Simulation (LES) also in complex flow applications. In this context, the practice of an implicit LES (ILES) based on the Discontinuous Galerkin (DG) method showed to be very promising due to the good dispersion and dissipation properties of DG methods. However, to date, characteristic Reynolds numbers of many industrial applications are too large for a fully resolved LES. For these applications the use of a hybrid RANS-LES model or a wall modelled LES approach seems mandatory. In hybrid RANS-LES models the RANS equations are active close to solid walls, where LES would be prohibitively costly, while LES is used in regions of separated flow where larger eddies can be resolved.

OBJECTIVES: The risk factors for oesophageal achalasia, a precancerous condition that can lead to epidermoid carcinoma, are unknown. The aim of this study was to determine these factors. METHODS: Beginning in 1973, patients presenting with achalasia from 1955 to 2016 periodically underwent clinical assessment, the barium swallow test (the oesophageal diameter and residual barium column were measured) and endoscopy according to a prospective protocol. We included patients with the minimum follow-up duration of 12 months. RESULTS: Of 681 cases, 583 patients were considered. The median follow-up time was 147.13 months (interquartile range 70.42-257.82 months), and 17 epidermoid carcinomas and 1 carcinosarcoma were diagnosed. After excluding 4 achalasia patients admitted with a cancer diagnosis, the incidence rate of epidermoid carcinomas was 1.61/1000 persons-year, and the cumulative probability of developing cancer at 56.34 years of follow-up was 13%. Risk factors for cancer were a sigmoid oesophagus [risk ratio (RR) = 17.64, 95% confidence interval (CI) 4.13-75.43], duration of achalasia symptoms >280 months (RR = 19.62, 95% CI 4.59-83.80), duration of follow-up >353 months (RR = 5.96, 95% CI 2.50-14.18), oesophageal diameter at diagnosis >71 mm (RR = 21.07, 95% CI 9.29-47.82), residual barium column at diagnosis >23 cm (RR = 24.27, 95% CI 6.93-85.01) and residual barium column at the last follow-up >10 cm (RR = 8.15, 95% CI 2.40-27.62). Conversely, the risk of epidermoid carcinoma was lower when the residual barium swallow decreased by >57% (RR = 0.10, 95% CI 0.03-0.34). CONCLUSIONS: Patients with achalasia carry a substantial risk of developing epidermoid carcinoma. Several factors, such as sigmoid achalasia and dysphagia lasting more than 23 years, are associated with an increased risk of cancer. An effective Heller myotomy may positively influence the carcinogenetic process.

The paper presents an approach to mesh adaptation suitable for scale resolving simulations. The methodology is based on the entropy adjoint approach, which corresponds to a standard output-based adjoint method with output functional targeting areas of spurious generation of entropy. The method shows several advantages over standard output-based error estimation: i) it is computationally inexpensive, ii) does not require the solution of a fine-space adjoint problem, and iii) is nonlinearly stable with respect to the primal solution for chaotic dynamical systems. In addition, the work reports on the parallel efficiency of the solver, which has been optimized through a multi-constraint domain decomposition algorithm available within the Metis 5.0 library.1 The reliability, accuracy, and efficiency of the approach are assessed by computing three test cases: the two-dimensional, laminar, chaotic flow around a square at Re = 3 000, the implicit Large Eddy Simulation (LES) of a circular cylinder at Re = 3 900, and the ILES of a square cylinder at Re = 22 000. The results show significant reduction in the number of DoFs with respect to uniform order-refinement, and good agreement with experimental data.