3,072 research outputs found

    Including Limited Partners in the Diversity Jurisdiction Analysis

    Get PDF
    This paper presents the results of the Dynamic Pricing Challenge, held on the occasion of the 17th INFORMS Revenue Management and Pricing Section Conference on June 29–30, 2017 in Amsterdam, The Netherlands. For this challenge, participants submitted algorithms for pricing and demand learning of which the numerical performance was analyzed in simulated market environments. This allows consideration of market dynamics that are not analytically tractable or can not be empirically analyzed due to practical complications. Our findings implicate that the relative performance of algorithms varies substantially across different market dynamics, which confirms the intrinsic complexity of pricing and learning in the presence of competition

    Correlation of esophageal pressure-flow analysis findings with bolus transit patterns on videofluoroscopy

    Get PDF
    This is a pre-copyedited, author-produced version of an article accepted for publication in Diseases of the Esophagus following peer review. The version of record Omari TI, Szczesniak MM, Maclean J, Myers JC, Rommel N, Cock C and Cook IJ. Correlation of esophageal pressure-flow analysis findings with bolus transit patterns on videofluoroscopy. Dis Esophagus. 2016 Feb-Mar;29(2):166-73. and is available online at: http://dx.doi.org/10.1111/dote.12300 Copyright © 2017 The International Society for Diseases of the EsophagusPressure-flow analysis quantifies the interactions between bolus transport and pressure generation. We undertook a pilot study to assess the interrelationships between pressure-flow metrics and fluoroscopically determined bolus clearance and bolus transport across the esophagogastric junction (EGJ). We hypothesized that findings of abnormal pressure-flow metrics would correlate with impaired bolus clearance and reduced flow across the EGJ. Videofluoroscopic images, impedance, and pressure were recorded simultaneously in nine patients with dysphagia (62–82 years, seven male) tested with liquid barium boluses. A 3.6 mm diameter solid-state catheter with 25 × 1 cm pressure/12 × 2 cm impedance was utilized. Swallowed bolus clearance was assessed using a validated 7-point radiological bolus transport scale. The cumulative period of bolus flow across the EGJ was also fluoroscopically measured (EGJ flow time). Pressure only parameters included the length of breaks in the 20 mmHg iso-contour and the 4 second integrated EGJ relaxation pressure (IRP4s). Pressure-flow metrics were calculated for the distal esophagus, these were: time from nadir impedance to peak pressure (TNadImp to PeakP) to quantify bolus flow timing; pressure flow index (PFI) to integrate bolus pressurization and flow timing; and impedance ratio (IR) to assess bolus clearance. When compared with controls, patients had longer peristaltic breaks, higher IRs, and higher residual EGJ relaxation pressures (break length of 8 [2, 13] vs. 2 [0, 2] cm, P = 0.027; IR 0.5 ± 0.1 vs. 0.3 ± 0.0, P = 0.019; IRP4s 11 ± 2 vs. 6 ± 1 mmHg, P = 0.070). There was a significant positive correlation between higher bolus transport scores and longer peristaltic breaks (Spearman correlation r = 0.895, P < 0.001) and with higher IRs (r = 0.661, P < 0.05). Diminished EGJ flow times correlated with a shorter TNadImp to PeakP (r = −0.733, P < 0.05) and a higher IR (r = −0.750, P < 0.05). Longer peristaltic breaks and higher IR correlate with failed bolus clearance on videofluoroscopy. The metric TNadImp to PeakP appears to be a marker of the period of time over which the bolus flows across the EGJ

    Angiogenesis in Paget's Disease of the Vulva and the Breast: Correlation with Microvessel Density

    Get PDF
    Our understanding of the pathogenesis of Paget's disease of the vulva and the breast remains limited. Current evidence supports the fact that angiogenesis plays an important role in the pathogenesis of several diseases. Therefore, we sought to define its role, as correlated with microvessel density, in Paget's disease of the vulva and the breast. Microvessels were analysed using anti-von Willebrand factor antibody in 105 cases of Paget's disease of the vulva and the breast comprising 71 cases of Paget's disease of the vulva, including 8 cases with invasive disease, and 34 cases of Paget's disease of the breast. The latter included 12 cases with DCIS, 5 cases with both DCIS and invasive carcinoma, and 6 with carcinoma alone. Eleven cases had no underlying tumour identified. Increased microvessel density was demonstrated in Paget's disease of the breast with DCIS and with carcinoma alone compared to Paget's disease of the breast alone, P < 0.08 and P < 0.013, respectively. There were no significant differences in microvessel density in the vulval cases. Neovascularisation is an important process in the development of Paget's disease of the breast. Other biological and molecular processes are more involved in the pathogenesis of Paget's disease of the vulva

    Inter-rater reliability and validity of automated impedance manometry analysis and fluoroscopy in dysphagic patients after head and neck cancer radiotherapy

    Get PDF
    This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving'.Copyright © 2015 John Wiley & Sons, Inc. All rights reserved.Introduction: Automated Impedance manometry (AIM) pressure-flow analysis is novel non-radiological method to analyse swallowing function based on impedance-pressure recordings of pharyngeal swallows. In a population of dysphagic head and neck cancer patients, we evaluated the reliability and validity of the AIM-derived swallow risk index (SRI) and a novel measure of post-swallow residue (iZn/Z) by comparing it against videofluoroscopy as the gold standard for assessing aspiration and post-swallow residue risk. Materials and Methods: Three blinded experts classified 88 videofluoroscopic swallows from 16 patients for aspiration and the degree of post-swallow residue using validated videofluroscopy scales. Pressure-impedance recordings of the swallows were also analysed using automated analysis software by one expert and two novice observers who derived the SRI and iZn/Z. Inter-observer concordance for videofluoroscopic and AIM measures was assessed using intraclass correlation coefficients (ICC). Patient SRI and iZn/Z measurements were compared with videofluoroscopy scores and control subjects to determine validity for detecting clinically relevant swallowing dysfunction. . Results: Among individual swallows, agreement among observers assessing presence of penetration and aspiration on videofluoroscopy was modest (ICC 0.57). Agreement among observers for AIM-derived swallow risk index (SRI) and the iZn/Z was good (ICC of 0.71 and ICC of 0.82 respectively). When compared with age-matched controls the SRI was higher in patients with aspiration (mean diff. 28.6, 95% CI [55.85 1.355], p<0.05). The iZn/Z was increased, suggesting greater post-swallow residues, in both patients with aspiration (Δ244 [419.7, 69.52, p<0.05]) and penetration (Δ240 [394.3, 85.77, p<0.05]) compared to controls. Discussion: AIM based measures of swallowing function have better inter-rater reliability than comparable fluoroscopically-derived measures. These measures can be easily determined and are objective markers of clinically relevant features of disordered swallowing following head and neck cancer therapy

    Biomechanics of Pharyngeal Deglutitive Function Following Total Laryngectomy

    Get PDF
    Copyright © 2016 American Academy of Otolaryngology—Head and Neck Surgery Foundation. Reprinted by permission of SAGE PublicationsObjective: Post-laryngectomy surgery, pharyngeal weakness and pharyngoesophageal junction (PEJ) restriction are the underlying candidate mechanisms of dysphagia. We aimed to determine, in laryngectomees whether: 1) hypopharyngeal propulsion is reduced and/or PEJ resistance is increased; 2) endoscopic dilatation improves dysphagia; and 3) if so, whether symptomatic improvement correlate with reduction in resistance to flow across the PEJ. Methods: Swallow biomechanics were assessed in 30 total laryngectomees. Average peak contractile pressure (hPP) and hypopharyngeal intrabolus pressure (hIBP) were measured from combined high resolution manometry and video-fluoroscopic recordings of barium swallows (2, 5&10ml). Patients were stratified into severe dysphagia (Sydney Swallow Questionnaire (SSQ)>500) and mild/nil dysphagia (SSQ≤500). In 5 patients, all measurements were repeated after endoscopic dilatation. Results: Dysphagia was reported by 87%, and 57% had severe and 43% had minor/nil dysphagia. Laryngectomees had lower hPP than controls (110±14mmHg vs 170±15mmHg; p<0.05), while hIBP was higher (29±5mmHg vs 6±5mmHg; p<0.05). There were no differences in hPP between patient groups. However, hIBP was higher in severe than in mild/nil dysphagia (41±10mmHg vs 13±3mmHg; p<0.05). Pre-dilation hIBP (R2=0.97) and its decrement following dilatation (R2=0.98) were good predictors of symptomatic improvement. Conclusion: Increased PEJ resistance is the predominant determinant of dysphagia as it correlates better with dysphagia severity than peak pharyngal contractile pressure. While both baseline PEJ resistance and its decrement following dilatation are strong predictors of outcome following dilatation, the peak pharyngeal pressure is not. PEJ resistance is vital to detect as it is the only potentially reversible component of dysphagia in this context
    corecore