Can we improve outcome of congenital diaphragmatic hernia?

This review gives an overview of the disease spectrum of congenital diaphragmatic hernia (CDH). Etiological factors, prenatal predictors of survival, new treatment strategies and long-term morbidity are described. Early recognition of problems and improvement of treatment strategies in CDH patients may increase survival and prevent secondary morbidity. Multidisciplinary healthcare is necessary to improve healthcare for CDH patients. Absence of international therapy guidelines, lack of evidence of many therapeutic modalities and the relative low number of CDH patients calls for cooperation between centers with an expertise in the treatment of CDH patients. The international CDH Euro-Consortium is an example of such a collaborative network, which enhances exchange of knowledge, future research and development of treatment protocols

Analyzing the influence of correlation length in permeability on convective systems in heterogeneous aquifers using entropy production

Hydrothermal convection in porous geothermal reservoir systems can be seen as a double-edged sword. On the one hand, regions of upflow in convective systems can increase the geothermal energy potential of the reservoir; on the other hand, convection introduces uncertainty, because it can be difficult to locate these regions of upflow. Several predictive criteria, such as the Rayleigh number, exist to estimate whether convection might occur under certain conditions. As such, it is of interest which factors influence locations of upwelling regions and how these factors can be determined. We use the thermodynamic measure entropy production to describe the influence of spatially heterogeneous permeability on a hydrothermal convection pattern in a 2D model of a hot sedimentary aquifer system in the Perth Basin, Western Australia. To this end, we set up a Monte Carlo study with multiple ensembles. Each ensemble contains several hundred realizations of spatially heterogeneous permeability. The ensembles only differ in the horizontal spatial continuity (i.e., correlation length) of permeability. The entropy production of the simulated ensembles shows that the convection patterns in our models drastically change with the introduction and increase of a finite, lateral correlation length in permeability. An initial decrease of the average entropy production number with increasing lateral correlation length shows that fewer ensemble members show convection. When neglecting the purely conductive ensembles in our analysis, no significant change in the number of convection cells is seen for lateral correlation lengths larger than 2000 m. The result suggests that the strength of convective heat transfer is not sensitive to changes in lateral correlation length beyond a specific factor. It does, however, change strongly compared to simulations with a homogeneous permeability field. As such, while the uncertainty in spatial continuity of permeability may not strongly influence the convective heat transfer, our findings show that it is important to consider spatial heterogeneity and continuity of permeability when simulating convective heat transfer in an aquifer.ISSN:2195-970

Autoignition of Dead Shrub Twigs: Influence of Diameter on Ignition

International audienceThe effect of the diameter of dead twigs of Cistus monspeliensis on their ignition was studied experimentally and theoretically. Autoignition experiments were carried out in a cone calorimeter. The ignition time, surface temperature before ignition, flame residence time, smoldering time and mass loss were measured. The particles were classified into two groups based on their ignitability. The first group contained the most flammable twigs, which had diameters smaller than or equal to 4 mm, along with leaves. The second one included twigs with diameters equal to or larger than 5 mm. For a radiant heat flux of 50 kW/m2, the 4-mm value appeared to be the upper limit for the size of the particles potentially involved in the spread dynamics of wildfires. However, bark detachment was observed on the thickest twigs, which greatly decreased their ignition time. Two ignition criteria were investigated: the ignition temperature and critical mass flux. The ignition temperature increased with the twig diameter, showing that this quantity should be carefully considered in ignition models. A thermal ignition model was proposed to determine the ignition time of twigs according to their diameter. The critical mass flux appeared to be fairly constant for any fuel diameter and could also be convenient for modeling the ignition of shrub fuels