Hospital readmissions have become a more examined indicator of surgical care delivery and quality. There is scarcity of data in the literature on the rate, risk factors, and most common reasons of ...readmission following major hiatal hernia surgery. The primary endpoint was 90-day readmission after surgery for large hiatal hernia. Secondary endpoint was to examine which characteristics related with a higher risk of readmission.
A retrospective review of two distinct institutional databases was performed for patients who had surgery for a large hiatal hernia between January 2012 and December 2019. Demographic, perioperative, and outpatient data were collected from the medical record.
A total of 71 patients met the inclusion criteria, most of them suffering from a type III hernia (66.2%). Mean operative time was 146 (±56.5) minutes and median length of stay (LOS) was 6 days (interquartile range = 3). The overall morbidity was 21.1% and the in-hospital mortality was 1.4%. The 30- and 90-day readmission rates were 7% and 8.5%, respectively. The mean time to readmission was 14.3 (±15.6) days. The reasons for 90-day hospital readmission were dysphagia (50%), pneumonia (16.7%), congestive heart failure (16.7%), and bowel obstruction (16.7%). Grade of esophagitis ≥2, presence of Barrett's esophagus, and LOS longer than 8 days were significant risk factors for unplanned readmission within 90 days.
We observed that about 6 out of 71 patients who had surgery readmitted within 90 days (8.5%). Readmissions were most often linked to esophagitis ≥2, presence of Barrett's esophagus, and LOS longer than 8 days. These findings point to the necessity for focused treatments before, during, and after hospitalization to decrease morbidity and extra costs in this high-risk population.
The study that we present is part of the preparation work for the setup of the FOOT (FragmentatiOn Of Target) experiment whose main goal is the measurement of the double differential cross sections ...of fragments produced in nuclear interactions of particles with energies relevant for particle therapy. The present work is focused on the characterization of the gas-filled drift chamber detector composed of 36 sensitive cells, distributed over two perpendicular views. Each view consists of six consecutive and staggered layers with three cells per layer. We investigated the detector efficiency and we performed an external calibration of the space–time relations at the level of single cells. This information was then used to evaluate the drift chamber resolution. An external tracking system realized with microstrip silicon detectors was adopted to have a track measurement independent on the drift chamber. The characterization was performed with a proton beam at the energies of 228 and 80 MeV. The overall hit detection efficiency of the drift chamber has been found to be 0.929±0.008, independent on the proton beam energy. The spatial resolution in the central part of the cell is about 150±10μ m and 300±10μ m and the corresponding detector angular resolution has been measured to be 1.62±0.16 mrad and 2.1±0.4 mrad for the higher and lower beam energies, respectively. In addition, the best value on the intrinsic drift chamber resolution has been evaluated to be in the range 60−100μ m. In the framework of the FOOT experiment, the drift chamber will be adopted in the pre-target region, and will be exploited to measure the projectile direction and position, as well as for the identification of pre-target fragmentation events.
This PhD thesis presents two measurements of differential production cross section of top and anti-top pairs tt ̅ decaying in a lepton+jets final state. The normalize cross section is measured as a ...function of the top transverse momentum and the tt ̅ mass, transverse momentum and rapidity using the full 2011 proton-proton (pp) ATLAS data taking at a center of mass energy of √s=7 TeV and corresponding to an integrated luminosity of L=4.6 〖fb〗^(-1). The cross section is also measured at the particle level as a function of the hadronic top transverse momentum for highly energetic events using the full 2012 data taking at √s=8 TeV and with L=20 〖fb〗^(-1). The measured spectra are fully corrected for detector efficiency and resolution effects and are compared to several theoretical predictions showing a quite good agreement, depending on different spectra.
Stable tracking in variable time-delay teleoperation Benedetti, C.; Franchini, M.; Fiorini, P.
Proceedings 2001 IEEE/RSJ International Conference on Intelligent Robots and Systems. Expanding the Societal Role of Robotics in the the Next Millennium (Cat. No.01CH37180),
2001, Letnik:
4
Conference Proceeding
Describes an improved architecture, for the control of force-feedback teleoperation in the presence of variable communication time-delay between the master and the slave. It is based on wave variable ...transformations and identification of time delay properties. This scheme achieves better position and force tracking than similar architectures, by estimating the current value of time delay and compensating its variations by adjusting a single control parameter. We derive some of the analytical properties of this scheme, and we show system performance by simulating a simple Internet-based teleoperation system.
Abstract
Massive black hole binaries are predicted to form during the hierarchical assembly of cosmic structures and will represent the loudest sources of low-frequency gravitational waves (GWs) ...detectable by present and forthcoming GW experiments. Before entering the GW-driven regime, their evolution is driven by the interaction with the surrounding stars and gas. While stellar interactions are found to always shrink the binary, recent studies predict the possibility of binary outspiral mediated by the presence of a gaseous disk, which could endlessly delay the coalescence and impact the merger rates of massive binaries. Here we implement a semianalytical treatment that follows the binary evolution under the combined effect of stars and gas. We find that binaries may outspiral only if they accrete near or above their Eddington limit and only until their separation reaches the gaseous disk self-gravitating radius. Even in case of an outspiral, the binary eventually reaches a large enough mass for GW to take over and drive it to coalescence. The combined action of stellar hardening, mass growth, and GW-driven inspiral brings binaries to coalescence in a few hundreds of megayears at most, implying that gas-driven expansion will not severely affect the detection prospects of upcoming GW facilities.
Supermassive black hole binaries (SMBHBs) are binary systems formed by black holes with masses exceeding millions of solar masses, and are expected to form and evolve in the nuclei of galaxies. The ...extremely compact nature of these objects leads to the intense and efficient emission of gravitational waves (GWs), which can be detected by the Pulsar Timing Array (PTA) experiment in the form of a gravitational wave background (GWB); that is, a superposition of GW signals coming from different sources. The modelling of the GWB requires some assumptions as to the binary population, and exploration of the whole parameter space involved is hindered by the great computational cost involved. We trained two neural networks (NN) on a semi-analytical modelling of the GWB generated by an eccentric population of MBHBs that interact with the stellar environment. We then used the NN to predict the characteristics of the GW signal in regions of the parameter space that we did not sample analytically. The developed framework allows us to quickly predict the amplitude, shape, and variance of the GWB signals produced in different realisations of the universe.
We studied the dynamical evolution of quasi-circular, equal-mass massive black hole binaries embedded in circumbinary discs from separations of ∼100 R g down to the merger, following the post merger ...evolution. The binary orbit evolves owing to the presence of the gaseous disc and the addition of post-Newtonian (PN) corrections up to the 2.5 PN order, therefore including the dissipative gravitational wave back reaction. We investigated two cases of relatively cold and warm circumbinary discs, with aspect ratios of H / R = 0.03, 0.1, respectively, employing 3D hyper-Lagrangian resolution simulations with the GIZMO -MFM code. We extracted spectral energy distributions and light curves in different frequency bands (i.e. X-ray, optical, and UV) from the simulations. We find a clear two orders of magnitude drop in the X-ray flux right before merger if the disc is warm, while we identify a significant increase in the UV flux regardless of the disc temperature. The optical flux shows clear distinctive modulations on the binary orbital period and on the cavity edge period, regardless of the disc temperature. We find that the presence of a cold disc can accelerate the coalescence of the binary by up to 130 s over the last five days of inspiral, implying a phase shift accumulation of about 0.14 radians compared to the binary evolution in vacuum. These differences are triggered by the presence of the gaseous disc and might have implications on the waveforms that can be detected in principle. We discuss the implications that these distinctive signatures might have for existing and upcoming time domain surveys and for multi-messenger astronomy.
X-ray quasi-periodic eruptions (QPEs) represent a recently discovered example of extreme X-ray variability associated with supermassive black holes. These are high-amplitude bursts recurring every ...few hours that are detected in the soft X-ray band from the nuclei of nearby galaxies whose optical spectra lack the broad emission lines typically observed in unobscured active galaxies. The physical origin of this new X-ray variability phenomenon is still unknown and several theoretical models have been presented. However, no attempt has been made so far to account for the varying QPE recurrence time and luminosity in individual sources, nor for the diversity of the QPE phenomenology in the different known erupters. We present a semi-analytical model based on an extreme mass-ratio inspiral (EMRI) system where the secondary intersects, along its orbit, a rigidly precessing accretion disc surrounding the primary. We assume that QPEs result from emission from an adiabatically expanding, initially optically thick gas cloud expelled from the disc plane at each impact. We produced synthetic X-ray light curves, which we then compared with X-ray data from four QPE sources: GSN 069, eRO-QPE1, eRO-QPE2, and RX J1301.9+2747. Our model aptly reproduces the diversity of QPE properties between the considered objects and it is also able to naturally account for the varying QPE amplitudes and recurrence times in individual sources. Future implementations will enable us to refine the match with the data and to estimate the system parameters precisely, making additional use of multi-epoch QPE data. We briefly discuss the nature of the secondary object, as well as the possible implications of our findings for the EMRI population at large.
Prophylaxis represents a keystone to reduce periocular skin and ocular conjunctiva bacterial load before surgical procedures. Despite many prophylactic agents are available the preferred ...perioperative ocular surface antimicrobial is still unknown. The purpose of this study was to assess the effectiveness of preoperative liposomal ozone dispersion in reducing bacterial colonization from the conjunctival sac and periocular skin in dogs, in comparison with povidone-iodine and fluoroquinolone. Twenty-two owned dogs consisting with 44 eyes in total scheduled for ophthalmic surgical procedure were enrolled for the study and divided in four groups receiving either ozone dispersion or povidone iodine in eyelid and conjunctiva, fluoroquinolone or placebo. A swab was taken before and after the antisepsis protocol evaluating total microbial count, coagulase positive and negative staphylococci. Statistical analysis revealed a significant decrease in colony forming units (CFU) for total microbial count, coagulase positive and negative staphylococci both for liposomal ozone dispersion and povidone iodine. No statistical differences were detected in median CFU for both one-day placebo and fluoroquinolone preoperative prophylactic topical therapy. The results of this preliminary study demonstrate that liposomal ozone-dispersion is as effective as povidone iodine to reduce preoperative bacterial load in ocular surface.
•Prophylaxis is crucial to preoperatively reduce ocular surface bacterial and the ideal antimicrobial agent is still unknown.•Ozone decrease bacterial load facilitating the formation of hydrogen- and lipo-peroxide from reactive oxygen species.•Liposomal ozone dispersion is as effective as 5% povidone-iodine in reducing conjunctival bacterial populations.
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