1,721,107 research outputs found
In Reply to the Letter to the Editor Regarding “Burnout Among Neurosurgeons and Residents in Neurosurgery: A Systematic Review and Meta-Analysis of the Literature”
No full textIn Reply to the Letter to the Editor Regarding “Burnout Among Neurosurgeons and Residents in Neurosurgery: A Systematic Review and Meta-Analysis of the Literature”
No full textLagrangian Raylaigh-Bénard convection
No full textUsing passive tracers as sensors, we obtain Lagrangian measurements of tracers position, velocity and temperature in Rayleigh-Bénard convection at Ra ∼ 107 ÷ 109. We report on statistics of temperature, velocity, and heat transport (Nusselt number). We observe that the Nusselt number is characterized by a largely intermittent behavior, likely due to the interaction of temperature with turbulent velocity fluctuations
Lagrangian Raylaigh-Bénard convection
No full textUsing passive tracers as sensors, we obtain Lagrangian measurements of tracers position, velocity and temperature in Rayleigh-Bénard convection at Ra=10^7-10^9. We report on statistics of temperature, velocity, and heat transport (Nusselt number). We observe that the Nusselt number is characterized by a largely intermittent behavior, likely due to the interaction of temperature with turbulent velocity fluctuations
Intermittency in elastic wave turbulence
No full textWe study numerically the long-time evolution of waves of a thin elastic plate for different energy input. In particular, we focus on the possible existence of intermittency, intended mainly as highly non-gaussian features. We show that deviations from the Kolmogorov- Zakharov scenario are present in high-order structure functions of the deplacement. This is more pronounced for higher- energy input even though the limit of small deformation so that modes of oscillations interact weakly is globally kept valid
Burnout Among Neurosurgeons and Residents in Neurosurgery: A Systematic Review and Meta-Analysis of the Literature
No full textBackground: Burnout syndrome (BS) is a common condition among medical professionals. It is composed of 3 different subdimensions: emotional exhaustion (EE), depersonalization (DP), and reduced personal accomplishment (PA). In the last years, interest in BS in the neurosurgical community has increased. Here we investigated burnout among neurosurgeons and residents in neurosurgery. Methods: A systematic review with meta-analysis was performed following PRISMA guidelines. A search of bibliographic databases was conducted from study inception to February 2020. A total of 16,377 studies were found. Six articles were included in our final analysis. Their references were checked for additional studies, but none were found. Results: From the initial 16,377 studies identified, only 6 met our inclusion criteria. These studies included a total of 3310 physicians. The general prevalence of BS was 48%. The prevalence in neurosurgeons was 51.1%, higher than that recorded in neurosurgical residents (45.4%). Regarding subdimensions, personal accomplishment seemed to be the most influential factor for burnout development among neurosurgeons (42.57%) and residents (51.56%) alike. Conclusions: Neurosurgery is a rewarding career choice, but numerous challenges and stressors can lead to lower levels of satisfaction and dangerously increased levels of burnout. We hope that our results will generate discussion, raise awareness, stimulate further studies, and lead to programs designed to mitigate excessive stress and burnout in neurosurgeons
Temperature dynamics in decaying isotropic turbulence with Joule heat production
No full textThis paper presents an extension of existing works dealing with the dynamics of a passive scalar in freely decaying isotropic turbulence, by accounting for a production mechanism of the passive scalar itself. The physically relevant case of the temperature dynamics in the presence of Joule heating via the dissipation of the turbulent kinetic energy is selected and analysed by theoretical and numerical means. In particular, the sensitivity of the temperature decay to the non-dimensional parameters Prandtl number (Pr) and Eckert number (Ec), the latter measuring the intensity of the internal energy production mechanism, is investigated. The time behaviour of the global quantities such as the temperature variance -2.t/ and its destruction rate "- .t/ is analysed, and a detailed analysis of the temperature variance spectrum E- .k/ is provided. In the case of a very strong heating mechanism, some important modifications of the temperature dynamics are observed. The time-decay-law exponents of the global physical quantities assume new values, which are governed only by features of the kinetic energy spectrum, while they depend on the shape of E- .k/ in the classical free-decay case. The temperature variance spectrum E- .k/ exhibits two new spectral ranges. One is a convective-production range such that E- .k/ / k1=3 is observed for a finite time at all values of Pr. In the case of very diffusive fluids with Pr - 1, a convective-diffusive-production range with E- .k/ / k7=3 is also detected. © 2013 Cambridge University Press
A Lagrangian probability-density-function model for collisional turbulent fluid-particle flows
No full textInertial particles in turbulent flows are characterised by preferential concentration and segregation and, at sufficient mass loading, dense particle clusters may spontaneously arise due to momentum coupling between the phases. These clusters, in turn, can generate and sustain turbulence in the fluid phase, which we refer to as cluster-induced turbulence (CIT). In the present work, we tackle the problem of developing a framework for the stochastic modelling of moderately dense particle-laden flows, based on a Lagrangian probability-density-function formalism. This framework includes the Eulerian approach, and hence can be useful also for the development of two-fluid models. A rigorous formalism and a general model have been put forward focusing, in particular, on the two ingredients that are key in moderately dense flows, namely, two-way coupling in the carrier phase, and the decomposition of the particle-phase velocity into its spatially correlated and uncorrelated components. Specifically, this last contribution allows us to identify in the stochastic model the contributions due to the correlated fluctuating energy and to the granular temperature of the particle phase, which determine the time scale for particle-particle collisions. The model is then validated and assessed against direct-numerical-simulation data for homogeneous configurations of increasing difficulty: (i) homogeneous isotropic turbulence, (ii) decaying and shear turbulence and (iii) CIT
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