University of Duisburg-Essen

About: University of Duisburg-Essen is a education organization based out in Essen, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 16072 authors who have published 39972 publications receiving 1109199 citations.

Experimental study of pedestrian counterflow in a corridor

Abstract: In this work the results of a pedestrian counterflow experiment in a corridor of width 2 m are presented. 67 participants were divided into two groups with varying relative and absolute size and walked in opposite directions through a corridor. The video footage taken from the experiment was evaluated for passing times, walking speeds, fluxes and lane formation, including symmetry breaking. The results include comparatively large fluxes and speeds as well as a maximal asymmetry between left- and right-hand traffic. The sum of flow and counterflow in any case turns out to be larger than the flow in all situations without counterflow.

Transbronchial Cryobiopsies for the Diagnosis of Diffuse Parenchymal Lung Diseases: Expert Statement from the Cryobiopsy Working Group on Safety and Utility and a Call for Standardization of the Procedure.

Abstract: Transbronchial cryobiopsies (TBCB) have recently been introduced as a promising and safer alternative to surgical lung biopsy in the diagnostic approach to diffuse parenchymal lung diseases (DPLD). Despite a substantial and expanding body of literature, the technique has not yet been standardized and its place in the diagnostic algorithm of DPLD remains to be defined. In part, this reflects concerns over the diagnostic yield and safety of the procedure, together with the rapid spread of the technique without competency and safety standards; furthermore, there is a substantial procedural variability among centers and interventional pulmonologists. We report this expert statement proposed during the third international conference on "Transbronchial Cryobiopsy in Diffuse Parenchymal Lung Disease" (Ravenna, October 27-28, 2016), which formulates evidence- and expert-based suggestions on the indications, contraindications, patient selection, and procedural aspects of the procedure. The following 5 domains were reviewed: (1) what is the role of TBCB in the diagnostic evaluation of DPLD: patient selection; (2) pathological considerations; (3) contraindications and safety considerations; (4) how should TBCB be performed and in what procedural environment; and (5) who should perform TBCB. Finally, the existence of white paper recommendations may also reassure local hospital credentialing committees tasked with endorsing an adoption of the technique.

Set points, settling points and some alternative models: theoretical options to understand how genes and environments combine to regulate body adiposity.

Abstract: The close correspondence between energy intake and expenditure over prolonged time periods, coupled with an apparent protection of the level of body adiposity in the face of perturbations of energy balance, has led to the idea that body fatness is regulated via mechanisms that control intake and energy expenditure. Two models have dominated the discussion of how this regulation might take place. The set point model is rooted in physiology, genetics and molecular biology, and suggests that there is an active feedback mechanism linking adipose tissue (stored energy) to intake and expenditure via a set point, presumably encoded in the brain. This model is consistent with many of the biological aspects of energy balance, but struggles to explain the many significant environmental and social influences on obesity, food intake and physical activity. More importantly, the set point model does not effectively explain the ‘obesity epidemic’ – the large increase in body weight and adiposity of a large proportion of individuals in many countries since the 1980s. An alternative model, called the settling point model, is based on the idea that there is passive feedback between the size of the body stores and aspects of expenditure. This model accommodates many of the social and environmental characteristics of energy balance, but struggles to explain some of the biological and genetic aspects. The shortcomings of these two models reflect their failure to address the gene-by-environment interactions that dominate the regulation of body weight. We discuss two additional models – the general intake model and the dual intervention point model – that address this issue and might offer better ways to understand how body fatness is controlled.

Reactive Power Capability of Wind Turbines Based on Doubly Fed Induction Generators

Abstract: With the increasing penetration of wind turbines (WTs) grid utilities require extended reactive power supply capability not only during voltage dips but also in steady-state operation WTs with doubly fed induction generators (DFIG) are able to control active and reactive power independently The reactive power capability is subject to several limitations resulting from the voltage, current, and speed, which change with the operating point This paper discusses the steady-state reactive power loading capability of DFIG-based WTs by taking into account the most important physical phenomena restricting the reactive power supply of DFIG-based WT systems The active-reactive power diagram is systematically derived by considering the typical power-speed relationship and converter loading limits The authors discuss also some special operating modes limiting the reactive power capability together with aspects of modeling and control that give rise to these limitations