99 research outputs found
The evolution of the coastal dunes in the western Belgian coastal plain
Two main dune systems exist in the area west of Nieuwpoort: the Younger Dunes along the present coastline, and the Older Dunes isolated within the coastal plain near the French border and also running parallel to the coast. Both systems have recently been subjected to geological and palynological investigations. The Older dune system is believed to be older than 4300 B. P. The Younger Dune-area appears to have a complex history. A stretch of older dunesediments (however not as old as these of the Older dunesystem) was found underneath the Younger Dunes, also near the French border. The age of these sediments is ranging from 2800 B. P. to 900 B. P. Furthermore two subphases of Younger Dune-formation are distinguished. Prior to the 14th century A. D. the dune area consisted of a relatively level plain. The completion of this plain marked the end of an active eolian phase. This phase started in the 11th century A. D., probably as the result of an increased incidence of storm-floods at that time (the Dunkerque-3 transgression). From the end of the 14th century on, large parabolic dunes partially buried the former landsurface. Some of them are still moving nowadays. Here the evolution of the Younger Dunearea near De Panneis described in more detail including aspects of the vegetational history of the dune area and adjacent coastal plain. Some attention is also drawn on the position of former coastlines
The effect of wind turbines alongside motorways on drivers’ behaviour
This paper presents the results of a first study aimed at investigating whether the presence of wind turbines in close proximity to motorways leads to behavioural adaptations among passing drivers. Empirical data from loop detectors and temporary video cameras were analysed in a study employing a before-and-after design at a site near Rotterdam, The Netherlands. Analyses of driving speed and standard deviation of speed (corrected for trend effects through the use of control sites) were performed as well as analyses of the lateral position and standard deviation of the lateral position and an observation of serious traffic conflicts. The results showed that constructing wind turbines alongside a motorway led to some clearly observable effects on drivers’ behaviour. The analyses of the speed data showed that the mean speed was lowered by 2.24km/h (corrected for trend effects) after the construction of the wind turbines while the standard deviation of the speed significantly increased. After the construction of the wind turbines, drivers took a lateral position somewhat more to the left-hand side in their driving lane. There was an indication close to the 0.05 significance level (p=0.057) that the standard deviation of the lateral position slightly increased when the rotor blades were in transversal position. In the before period as well as in the after period, no serious traffic conflicts were registered. The increase in standard deviation of speed and in lateral position are two factors that intrinsically can have an unfavourable effect on road safety. However, the observed order of magnitude of the change was shown to be quite limited. Earlier research suggests that negative effects on road safety are only expected for changes substantially greater than the ones that were observed in this study. On the other hand, there was a significant reduction in driving speed, which might have a favourable effect on the expected number and severity of crashes, although it could also be a compensatory mechanism that indirectly indicates a reduced driving performance. From these findings, it can be concluded that, based on the observed variables, no substantial negative effects for road safety were found in the present study. The authors recommend continuous monitoring and further research on the topic
PAR1 Agonists Stimulate APC-Like Endothelial Cytoprotection and Confer Resistance to Thromboinflammatory Injury
Stimulation of protease-activated receptor 1 (PAR1) on endothelium by activated protein C (APC) is protective in several animal models of disease, and APC has been used clinically in severe sepsis and wound healing. Clinical use of APC, however, is limited by its immunogenicity and its anticoagulant activity. We show that a class of small molecules termed “parmodulins” that act at the cytosolic face of PAR1 stimulates APC-like cytoprotective signaling in endothelium. Parmodulins block thrombin generation in response to inflammatory mediators and inhibit platelet accumulation on endothelium cultured under flow. Evaluation of the antithrombotic mechanism showed that parmodulins induce cytoprotective signaling through Gβγ, activating a PI3K/Akt pathway and eliciting a genetic program that includes suppression of NF-κB–mediated transcriptional activation and up-regulation of select cytoprotective transcripts. STC1 is among the up-regulated transcripts, and knockdown of stanniocalin-1 blocks the protective effects of both parmodulins and APC. Induction of this signaling pathway in vivo protects against thromboinflammatory injury in blood vessels. Small-molecule activation of endothelial cytoprotection through PAR1 represents an approach for treatment of thromboinflammatory disease and provides proof-of-principle for the strategy of targeting the cytoplasmic surface of GPCRs to achieve pathway selective signaling
Proactive Evaluation of Traffic Signs Using a Traffic Sign Simulator
Traffic signs and pavement markings are a crucial aspect of road design since they are essential sources of information for road users to calibrate their driving behavior, evaluate route possibilities and cope with unexpected events. A proactive evaluation of (the quality of) these road design elements will help to improve the safety performance of the roadway. This paper presents the Traffic Sign Simulator, an innovative research tool to study the influence of these elements on road users’ routing decisions, lane choice and visual behavior, to investigate road users’ comprehension of these signs, and to collect suggestions for improvements. Using a driving simulator mock-up, participants navigate through a full HD video from route(s) in which the planned traffic signs have been digitally implemented using specialized software for camera-tracking and 3D video-integration. Participants’ route and lane choice and their visual behavior (using eye tracking) are monitored while driving through the scenario(s). Laptop preand post-tests are applied to collect additional in-depth information concerning the participants’ processing, comprehension and general evaluation of the traffic signs and suggestions for improvement. The paper illustrates the possibilities of the Traffic Sign Simulator with a case study that examined the effectiveness of temporary work zone signalization (i.e., traffic signs, digital information panels and pavement markings) as it was used during the reconstruction works on the Vilvoorde fly-over near Brussels, one of the busiest interchanges in the Belgian motorway network
Parmodulins Inhibit Thrombus Formation Without Inducing Endothelial Injury Caused by Vorapaxar
Protease-activated receptor-1 (PAR1) couples the coagulation cascade to platelet activation during myocardial infarction and to endothelial inflammation during sepsis. This receptor demonstrates marked signaling bias. Its activation by thrombin stimulates prothrombotic and proinflammatory signaling, whereas its activation by activated protein C (APC) stimulates cytoprotective and antiinflammatory signaling. A challenge in developing PAR1-targeted therapies is to inhibit detrimental signaling while sparing beneficial pathways. We now characterize a novel class of structurally unrelated small-molecule PAR1 antagonists, termed parmodulins, and compare the activity of these compounds to previously characterized compounds that act at the PAR1 ligand–binding site. We find that parmodulins target the cytoplasmic face of PAR1 without modifying the ligand-binding site, blocking signaling through Gαq but not Gα13 in vitro and thrombus formation in vivo. In endothelium, parmodulins inhibit prothrombotic and proinflammatory signaling without blocking APC-mediated pathways or inducing endothelial injury. In contrast, orthosteric PAR1 antagonists such as vorapaxar inhibit all signaling downstream of PAR1. Furthermore, exposure of endothelial cells to nanomolar concentrations of vorapaxar induces endothelial cell barrier dysfunction and apoptosis. These studies demonstrate how functionally selective antagonism can be achieved by targeting the cytoplasmic face of a G-protein–coupled receptor to selectively block pathologic signaling while preserving cytoprotective pathways
Cyclists in shared bus lanes: could there be unrecognised impacts on bus journey times?
This paper contributes to debates around improving the modelling of cycles, through an exploratory case study of bus–cycle interactions in London. This case study examines undocumented delays to buses caused by high volumes of cyclists in bus lanes. It has generally been assumed that cyclists do not noticeably delay buses in shared lanes. However, in many contexts where cyclists routinely share bus lanes, cyclist numbers have historically been low. In some such places, bus lanes are now seeing very high volumes of cyclists, far above those previously studied. This may have implications for bus – and cycle – journey times, but traditionally traffic modelling has not represented the effects of such interactions well. With some manipulation of parameters taken from models of other cities, the model described here demonstrates that cycles can cause significant delays to buses in shared lanes, at high cycling volumes. These delays are likely to become substantially larger if London's cycling demographic becomes more diverse, because cyclist speeds will decline. Hence bus journey time benefits may derive from separating cycles from buses, where cycle flows are high. The project also suggests that microsimulation modelling software, as typically used, remains problematic for representing cyclists
Identification of safety effects of infrastructure related measures, Deliverable 5.2 of the H2020 project SafetyCube
Identification of safety effects of infrastructure related measures, Deliverable 5.2 of the H2020 project SafetyCub
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