Does high-impact research come at the expense of quality? An automated analysis of the REF impact landscape

As part of the 2014 Research Excellence Framework, the impact of research was assessed for the first time. But how effective was the impact category in capturing the many diverse forms of interaction between academia and society? Were certain interpretations of impact more highly rewarded than others? And does high-impact research come at the expense of quality? Martin Zaltz Austwick and his research team used a text mining technique to analyse impact case study submissions and address some of these questions

Endommagement par fatigue et prédiction de la durée de vie des structures soudées de type caisson

The Chapter 9 of Eurocode 3 is one of the most widely adapted codes for fatigue life prediction of welded joints, the drawback of this code being the single curve fatigue strength for each type of welded joint produced regardless of the type of steel used. The fatigue strength of welded joints is particularly sensitive to the geometry of the weld bead and the stress fields which could potentially be introduced by the welding process or by other microscopic defects introduced by the welding. In this study the volumetric method, which has proven its validity in the study of fatigue, has been used to determine the effective stress in the plastic zone near the weld bead. Numerical simulations have been performed on a welded box to determine the stress distribution and gradient which would allow proper calculation of the effective stress. Both numerical simulations and experimental results support the validity of the volumetric method for such type of welded structuresLe chapitre 9 de L'Eurocode 3 est le moyen le plus utilisé par les ingénieurs pour prédire la durée de vie des joints soudés, mais ce code ne donne qu'une seule courbe de résistance en fatigue pour chaque type de joint soudé, quel que soit l'acier utilisé. La résistance à la fatigue des assemblages soudés est particulièrement sensible à la géométrie du cordon déposé, ainsi qu'aux champs de contraintes introduits, soit par le procédé de soudage, soit par les défauts microscopiques inclus dans le soudage. Nous avons donc besoin d'une méthode locale telle la méthode volumétrique, qui a donné de bons résultats en fatigue, pour déterminer la contrainte effective dans la zone plastifiée à côté du cordon de soudure. Une étude numérique est réalisée sur un caisson soudé. La distribution et le gradient de contrainte permettent de calculer la contrainte effective. Les résultats numériques, comparés aux résultats expérimentaux, ont validé la méthode volumétrique sur ce type de structures soudée

Miniforceps EBUS-Guided Lymph Node Biopsy: Impact on Diagnostic Yield

Introduction: Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) is the standard diagnostic method for sampling mediastinal and hilar lymph nodes. Non-diagnostic samples have led some pulmonologists to add a miniforceps biopsy (EBUS-TBFB) in order to increase diagnostic yield. Our study aims to analyze the impact of adding EBUS-TBFB to the EBUS-TBNA in cases where Rapid On-site Evaluation (ROSE) was negative for malignancy or was non-diagnostic. Material and methods: This retrospective chart review included 91 patients who were aged 18–90 years old and underwent EBUS with both TBNA and TBFB between January 1, 2013 and July 1, 2018. Results: There was no significant statistical difference in the diagnostic yield of TBNA vs TBFB with a McNemar value of 0.167, and this conclusion was the same when stratified by race, age and lymph node size. Using TBNA as a gold standard, the sensitivity and specificity of TBFB was 87% and 69%, respectively. Out of the non-diagnostic TBNA samples on ROSE and cell-block, subsequent TBFB resulted in additional pathologic diagnoses in 16% of cases, of which 67% were non-caseating granulomas. Furthermore, two additional malignant cases were identified by TBFB consisting of small cell carcinoma and non-Hodgkin’s lymphoma. Conclusion: In conclusion, TBFB is a useful adjunctive tool in the diagnosis of non-malignant conditions (i.e., granulomatous diseases) with the potential to spare the patient from more invasive surgical biopsies. Training of future fellows in performing TBFB in addition to TBNA should be strongly encouraged

Capture and long-term suspension of aerosols in an open cavity flow

International audienceThe motion of non-Brownian aerosols in an open laminar cavity flow is investigated by means of numerical and asymptotic methods. The cavity is a rectangular domain where air enters through an inlet located on the top, and exits in the horizontal direction through symmetric apertures near the bottom wall. While such flows are generally used to provide a clean (particle-free) environment, the introduction of any object inside the cavity can affect the flow topology and, in return, can lead to large aerosol residence times. In addition, it is known that the unsteadiness of the flow, though weak, significantly delays the exit of aerosols from the cavity. The goal of this paper is to analyze the conditions under which these phenomena occur, for heavy inertial particles with a small response time and a finite free-fall velocity, in a laminar cavity flow. A two-dimensional situation is considered and investigated by means of numerical simulations and perturbation methods, at moderate cavity Reynolds numbers. It is observed that any obstacle placed inside the cavity (along the symmetry axis) creates large quasi-steady triangular recirculation cells stretched by the outward flow, provided the Reynolds number is not too large. In particular, streamlines near the floor are reversed, so that deposited particles are swept inward and remain in the cavity. The probability of trapping has been calculated asymptotically, for inertia-free sedimenting particles, and compared to numerical results. Trapping in the wake of obstacles is observed to persist when the flow is slightly unsteady. In addition, it is shown that the small but finite unsteadiness of the flow can lead to the temporary trapping of a significant portion of particles by large recirculation cells near the upper corners of the cavity. This phenomenon takes place in spite of gravity and centrifuge effects due to the curvature of the cell, and leads to a long-term suspension which significantly increases the residence time of aerosols. By making use of separatrix map methods, the critical aerosol diameter below which this phenomenon occurs has been obtained and compared to numerical simulation results