Numerical Simulation of Compressible Vortical Flows Using a Conservative Unstructured-Grid Adaptive Scheme

A two-dimensional numerical scheme for the compressible Euler equations is presented and applied here to the simulation of exemplary compressible vortical flows. The proposed approach allows to perform computations on unstructured moving grids with adaptation, which is required to capture complex features of the flow-field. Grid adaptation is driven by suitable error indicators based on the Mach number and by element-quality constraints as well. At the new time level, the computational grid is obtained by a suitable combination of grid smoothing, edge-swapping, grid refinement and de-refinement. The grid modifications-including topology modification due to edge-swapping or the insertion/deletion of a new grid node-are interpreted at the flow solver level as continuous (in time) deformations of suitably-defined node-centered finite volumes. The solution over the new grid is obtained without explicitly resorting to interpolation techniques, since the definition of suitable interface velocities allows one to determine the new solution by simple integration of the Arbitrary Lagrangian-Eulerian formulation of the flow equations. Numerical simulations of the steady oblique-shock problem, of the steady transonic flow and of the start-up unsteady flow around the NACA 0012 airfoil are presented to assess the scheme capabilities to describe these flows accurately

Acquired tracheoesophageal fistula repair, due to prolonged mechanical ventilation, in patient with double incomplete aortic arch

We report a case of the repair of an acquired benign tracheoesophageal fistula (TEF) after prolonged mechanical invasive ventilation. Patient had an unknown double incomplete aortic arch determining a vascular ring above trachea and esophagus. External tracheobronchial compression, caused by the vascular ring, increasing the internal tracheoesophageal walls pressure determined by endotracheal and nasogastric tubes favored an early TEF development. The fistula was repaired through an unusual left thoracotomy and vascular ring dissection. TEFs are a heterogeneous group of diseases affecting critically ill patients. Operative closure is necessary to avoid further complications related to this condition. Pre-opera-tive study is mandatory to plan an adequate surgical approach

Pulmonary sclerosing pneumocytoma: A pre and intraoperative diagnostic challenge. report of two cases and review of the literature

Pulmonary sclerosing pneumocytoma is a rare benign pulmonary tumor of primitive epithelial origin. Because of the unspecific radiological features mimicking malignancies and its histological heterogeneity, the differential diagnosis with adenocarcinoma and carcinoid tumors is still challenging. We report our experience of two cases of sclerosing pneumocytoma, as well as a review of the literature. Immunohistochemical findings showed intense staining of the cuboidal epithelial cells for cytokeratin-pool and TTF-1, with focal positivity for progesterone receptors. Round and spindle cells expressed positivity for vimentin, TTF-1 and focally for the progesterone receptor. Cytologic diagnosis of pulmonary pneumocytoma requires the identification of its dual cell population, made up of abundant stromal cells and fewer surface cells. Since the pre-and intraoperative diagnosis should guide surgical decision making, obtaining a sufficient specimen size to find representative material in the cell block is of paramount importance

The clustering of X-ray selected AGN at z=0.1

The clustering properties of moderate luminosity ($L_X = \rm 10^{41} - 10^{44} \, erg \,s^{-1}$) X-ray selected AGN at $z\approx0.1$ are explored. X-ray sources in the redshift interval $0.03<z<0.2$ are selected from a serendipitous XMM survey of the SDSS footprint (XMM/SDSS) and are cross-correlated with the SDSS Main galaxy sample. The inferred X-ray AGN auto-correlation function is described by a power law with amplitude $r_0\approx5\,$h$^{-1}$Mpc and slope $\gamma\approx2.0$. The corresponding mass of the dark matter haloes that host X-ray AGN at $z\approx0.1$ is \approx 10^{13} \,h ^{-1} \, M_{\sun}. Comparison with studies at higher redshift shows that this mass scale is characteristic of moderate luminosity X-ray AGN out to $z\approx 1$. Splitting the AGN sample by rest-frame color shows that X-ray sources in red hosts are more clustered than those associated with blue galaxies, in agreement with results at $z\approx1$. We also find that the host galaxies of X-ray AGN have lower stellar masses compared to the typical central galaxy of a \approx 10^{13} \,h ^{-1} \, M_{\sun} dark matter halo. AGN hosts either have experienced less stellar mass growth compared to the average central galaxy of a \approx 10^{13} \,h ^{-1} \, M_{\sun} halo or a fraction of them are associated with satellite galaxies.Comment: MNRAS accepted 14 pages, 8 figures, 5 table

Multicenter randomized study on the comparison between electronic and traditional chest drainage systems

Background: In patients submitted to major pulmonary resection, the postoperative length of stay is mainly influenced by the duration of air leaks and chest tube removal. The measurement of air leaks largely relies on traditional chest drainage systems which are prone to subjective interpretation. Difficulty in differentiating between active air leaks and bubbles due to a pleural space effect may also lead to tentative drain clamping and prolonged time for chest drain removal. New digital systems allow continuous monitoring of air leaks, identifying subtle leakage that may be not visible during daily patient evaluation. Moreover, an objective assessment of air leaks may lead to a reduced interobserver variability and to an optimized timing for chest tube removal. Methods: This study is a prospective randomized, interventional, multicenter trial designed to compare an electronic chest drainage system (Drentech\u2122 Palm Evo) with a traditional system (Drentech\u2122 Compact) in a cohort of patients undergoing pulmonary lobectomy through a standard three-port video-assisted thoracic surgery approach for both benign and malignant disease. The study will enroll 382 patients in three Italian centers. The duration of chest drainage and the length of hospital stay will be evaluated in the two groups. Moreover, the study will evaluate whether the use of a digital chest system compared with a traditional system reduces the interobserver variability. Finally, it will evaluate whether the digital drain system may help in distinguishing an active air leak from a pleural space effect, by the digital assessment of intrapleural differential pressure, and in identifying potential predictors of prolonged air leaks. Discussion: To date, few studies have been performed to evaluate the clinical impact of digital drainage systems. The proposed prospective randomized trial will provide new knowledge to this research area by investigating and comparing the difference between digital and traditional chest drain systems. In particular, the objectives of this project are to evaluate the feasibility and usefulness of digital chest drainages and to provide new tools to identify patients at higher risk of developing prolonged air leaks. Trial registration: ClinicalTrials.gov, NCT03536130. Retrospectively registered on 24 May 2018

Resectable IIIA-N2 non-small-cell lung cancer (NSCLC): In search for the proper treatment

Locally advanced non-small cell lung cancer accounts for one third of non-small cell lung cancer (NSCLC) at the time of initial diagnosis and presents with a wide range of clinical and pathological heterogeneity. To date, the combined multimodality approach involving both local and systemic control is the gold standard for these patients, since occult distant micrometastatic disease should always be suspected. With the rapid increase in treatment options, the need for an interdisciplinary discussion involving oncologists, surgeons, radiation oncologists and radiologists has become essential. Surgery should be recommended to patients with non-bulky, discrete, or single-level N2 involvement and be included in the multimodality treatment. Resectable stage IIIA patients have been the subject of a number of clinical trials and retrospective analysis, discussing the efficiency and survival benefits on patients treated with the available therapeutic approaches. However, most of them have some limitations due to their retrospective nature, lack of exact pretreatment staging, and the involvement of heterogeneous populations leading to the awareness that each patient should undergo a tailored therapy in light of the nature of his tumor, its extension and his performance status

AMICO galaxy clusters in KiDS-DR3: Cosmological constraints from angular power spectrum and correlation function

We study the tomographic clustering properties of the photometric cluster catalogue derived from the Third Data Release of the Kilo Degree Survey, focusing on the angular correlation function and its spherical harmonic counterpart, the angular power spectrum. We measure the angular correlation function and power spectrum from a sample of 5162 clusters, with an intrinsic richness $\lambda^*\geq 15$, in the photometric redshift range $z\in [0.1, 0.6]$, comparing our measurements with theoretical models, in the framework of the $\Lambda$-Cold Dark Matter cosmology. We perform a Monte Carlo Markov Chain analysis to constrain the cosmological parameters $\Omega_{\mathrm{m}}$, $\sigma_8$ and the structure growth parameter $S_8\equiv\sigma_8 \sqrt{\Omega_{\mathrm{m}}/0.3}$. We adopt Gaussian priors on the parameters of the mass-richness relation, based on the posterior distributions derived from a previous joint analysis of cluster counts and weak lensing mass measurements carried out with the same catalogue. From the angular correlation function, we obtain $\Omega_{\mathrm{m}}=0.32^{+0.05}_{-0.04}$, $\sigma_8=0.77^{+0.13}_{-0.09}$ and $S_8=0.80^{+0.08}_{-0.06}$, in agreement, within $1\sigma$, with 3D clustering result based on the same cluster sample and with existing complementary studies on other datasets. For the angular power spectrum, we derive statistically consistent results, in particular $\Omega_{\mathrm{m}}=0.24^{+0.05}_{-0.04}$ and $S_8=0.93^{+0.11}_{-0.12}$, while the constraint on $\sigma_8$ alone is weaker with respect to the one provided by the angular correlation function, $\sigma_8=1.01^{+0.25}_{-0.17}$. Our results show that the 2D clustering from photometric cluster surveys can provide competitive cosmological constraints with respect to the full 3D clustering statistics, and can be successfully applied to ongoing and forthcoming spectro/photometric surveys.Comment: 14 pages, 9 figures. Submitted to Astronomy & Astrophysics (A&A

AMICO galaxy clusters in KiDS-DR3: cosmological constraints from counts and stacked weak-lensing

We present a cosmological analysis of abundances and stacked weak-lensing profiles of galaxy clusters, exploiting the AMICO KiDS-DR3 catalogue. The sample consists of 3652 galaxy clusters with intrinsic richness $\lambda^*\geq20$, over an effective area of 377 deg$^2$, in the redshift range $z\in[0.1,\,0.6]$. We quantified the purity and completeness of the sample through simulations. The statistical analysis has been performed by simultaneously modelling the comoving number density of galaxy clusters and the scaling relation between the intrinsic richnesses and the cluster masses, assessed through a stacked weak-lensing profile modelling. The fluctuations of the matter background density, caused by super-survey modes, have been taken into account in the likelihood. Assuming a flat $\Lambda$CDM model, we constrained $\Omega_{\rm m}$, $\sigma_8$, $S_8 \equiv \sigma_8(\Omega_{\rm m}/0.3)^{0.5}$, and the parameters of the mass-richness scaling relation. We obtained $\Omega_{\rm m}=0.24^{+0.03}_{-0.04}$, $\sigma_8=0.86^{+0.07}_{-0.07}$, $S_8=0.78^{+0.04}_{-0.04}$. The constraint on $S_8$ is consistent within 1$\sigma$ with the results from WMAP and Planck. Furthermore, we got constraints on the cluster mass scaling relation in agreement with those obtained from a previous weak-lensing only analysis.Comment: 12 pages, 7 figures, 2 tables. Accepted by A&

The VIMOS Public Extragalactic Redshift Survey (VIPERS). Never mind the gaps: comparing techniques to restore homogeneous sky coverage

[Abridged] Non-uniform sampling and gaps in sky coverage are common in galaxy redshift surveys, but these effects can degrade galaxy counts-in-cells and density estimates. We carry out a comparison of methods that aim to fill the gaps to correct for the systematic effects. Our study is motivated by the analysis of the VIMOS Extragalactic Redshift Survey (VIPERS), a flux-limited survey (i<22.5) based on one-pass observations with VIMOS, with gaps covering 25% of the surveyed area and a mean sampling rate of 35%. Our findings are applicable to other surveys with similar observing strategies. We compare 1) two algorithms based on photometric redshift, that assign redshifts to galaxies based on the spectroscopic redshifts of the nearest neighbours, 2) two Bayesian methods, the Wiener filter and the Poisson-Lognormal filter. Using galaxy mock catalogues we quantify the accuracy of the counts-in-cells measurements on scales of R=5 and 8 Mpc/h after applying each of these methods. We also study how they perform to account for spectroscopic redshift error and inhomogeneous and sparse sampling rate. We find that in VIPERS the errors in counts-in-cells measurements on R<10 Mpc/h scales are dominated by the sparseness of the sample. All methods underpredict by 20-35% the counts at high densities. This systematic bias is of the same order as random errors. No method outperforms the others. Random and systematic errors decrease for larger cells. We show that it is possible to separate the lowest and highest densities on scales of 5 Mpc/h at redshifts 0.5<z<1.1, over a large volume such as in VIPERS survey. This is vital for the characterisation of cosmic variance and rare populations (e.g, brightest galaxies) in environmental studies at these redshifts.Comment: 17 pages, 13 figures, accepted for publication in A&A (revised version after minor revision and language editing