13 research outputs found
A Framework to Evaluate Aircraft Trajectory Generation Methods
No full textAircraft trajectory generation is a widely addressed problem with applications including emergency trajectory generation, collision risk models, air traffic flow and capacity management or airspace design. State of the art methods to generate individual trajectories and optimise some performance or emergency criterion may lack of realism with respect to common situations implemented by air traffic controllers. On the other hand, statistical data-driven methods to generate aircraft trajectories excel at imitating operational practice but may be difficult to implement even in simulations due to aircraft performance limitations. This contribution proposes a common baseline to compare literature and bleeding-edge methods to generate air traffic trajectories. Keeping in mind that the most appropriate criterion should always depend on the targeted application, we present here an extensive set of metrics to evaluate the quality of generated trajectories, before assessing two generation methods in light of these indicators.Control & Simulatio
Adaptive optics: a tool for screening hydroxychloroquine-induced maculopathy?
No full textInternational audienc
Chemo-enzymatic synthesis of NPN cofactor taking advantage of ADP-ribosyl cyclase and LarC cyclometallase promiscuous activities
No full textThe nickel-pincer nucleotide cofactor (NPN) is a widespread organometallic cofactor required for lactate racemase (LarA) and for α-hydroxy acid racemases and epimerases of the LarA superfamily. Its biosynthesis, which starts with nicotinic acid adenine dinucleotide (NaAD), requires three enzymes: LarB, LarC, and LarE, and can be performed in vitro with purified enzymes. Nevertheless, as LarE and LarC are single turnover enzymes, the in vitro NPN biosynthesis requires huge amounts of enzymes (particularly 2 equivalents of LarE), which hampers the study of NPN and of NPN-dependent enzymes. By using adenosine diphosphate (ADP)-ribosyl cyclase (ARC), we exchanged the nicotinamide moiety in NAD+ with synthetic pyridine-3,5-bisthiocarboxylic acid in order to synthesize the novel intermediate pyridinium-3,5-bisthiocarboxylic acid adenine dinucleotide (P2TAD). The latter could be produced at a multimilligram scale allowing its characterization by Nuclear Magnetic Resonance (NMR) and mass spectrometry. Interestingly, P2TAD could directly be used by LarC in order to generate the NPN cofactor, bypassing both LarB and LarE. Globally, a new chemoenzymatic route towards NPN was developed via the intermediate P2TAD, which should facilitate the biochemical and biotechnological investigations on NPN binding enzymes
Provision of instructions to drink ad libitum or according to thirst sensation: impact during 120 km of cycling in the heat in men
No full textThe terms drinking to thirst and ad libitum drinking are used interchangeably, but should they? We investigated the differences in how athletes consume fluids during exercise when instructed to drink according to thirst or ad libitum. Using a randomized, crossover and counterbalanced design, 10 males (27 4 y) cycled 120 km (48 4% of peak power, 33C, 40% relative humidity) on two occasions, while drinking water according to thirst or ad libitum. Participants covered the cycling trials in 222 11 min (p = 0.29). Although the body mass loss at the end of exercise and total volume of water consumed were similar between trials, thirst perception before each sip and the volume consumed per sip were significantly higher with thirst than ad libitum drinking, whereas the total number of sips was significantly lower with thirst than ad libitum drinking. Perceived exertion, rectal temperature and heart rate were all significantly higher with thirst than ad libitum drinking, but the difference was trivial. In conclusion, thirst and ad libitum drinking are associated with different drinking patterns, but equally maintain fluid balance during prolonged exercise. The terms drinking to thirst and ad libitum drinking can be used interchangeably for guiding fluid intake during prolonged exercise.
NOVELTY
• Both strategies are associated with different patterns of fluid ingestion during prolonged exercise, but are equally effective in maintaining fluid balance;
• Perceived exertion, rectal temperature and heart rate are regulated dissimilarly by thirst and ad libitum drinking, but the difference is trivial.The presentation of the authors' names and (or) special characters in the title of the pdf file of the accepted manuscript may differ slightly from what is displayed on the item page. The information in the pdf file of the accepted manuscript reflects the original submission by the author
Clinical and biometric determinants of actual lens position after cataract surgery
No full textInternational audienc
Stress Assessment in Armour Layers of Flexible Risers
No full textThe accurate modeling of offshore flexible risers behaviour remains a great challenge because of (i) their complex internal structure, (ii) the variable nature of the loads along the pipe (tension, curvature, internal and external pressures), (iii) and the interactions with structures used to limit the pipe curvature. Technip and IFP have been codeveloping for many years models dedicated to stresses calculation in the armour wires, to assess the flexible lifetime. These models must account for a large number of potential inner contacts (contacts between upper and lower layers, lateral contacts between adjacent armour wires in the same layer) as well as external contacts (bend stiffener, arch, bellmouth or other curvature limitation setup). The paper presents a comparison between 3 models with different level of complexity and realism. The first one is a in house model, whereas the two others were developed on the basis of the commercial FE code Abaqus. The first model, Life6, is based on some simplified assumptions in particular the fact that periodic solutions are assumed (given constant curvature in the pipe) and uses analytical solutions of equilibrium of wires on a torus (the bend pipe). The effect of non uniform curvature (in particular end-fitting proximity) is not considered in this model. The second model, namely 3D/Periodic model, is still based on a periodic assumption, but can cope with severe loadings (such as large curvature of the pipe or compression) leading to specific wires contact interactions. Abaqus Standard (Implicit scheme) is used. The third model, called 3D/Explicit model, is a full length model, as it includes end fittings effects, outer structure (like stiffener) interactions and any curvatures variations along the pipe. All contacts interactions are considered. The number of DOFs involved in the analysis requires the use of an explicit integration scheme (Abaqus Explicit) running on a parallel platform. These models are cross validated on a dedicated case study that consisted of a pressurized pipe cyclically bent with constant curvature. The validation of the model results is very satisfying even when lateral contacts between wires occur. Finally, a comparison of the 3D/Explicit model results with experimental data is presented. This model provides a very good estimation of the flexible behavior and of the end fitting effects.</jats:p
High-capacity nations can unlock momentum for quality marine protection
No full textSummary.Highly and fully protected marine protected areas (HF-MPAs) deliver the strongest ecological outcomes, yet they cover just 3.8% of the ocean, and annual gains have stalled. We combine ProtectedSeas regulatory classifications with coastal habitat maps for corals, mangroves, seagrasses, and saltmarshes to track HF-MPAs and minimally/lightly protected MPAs (ML-MPAs) from 2000 to 2025 and overlay results with governance-based enabling conditions. HF-MPAs remain rare even in high-capacity countries that host most mapped coastal habitats and 39% of the global upgrade gap. Upgrading ML-MPAs in this small cohort—especially in overseas territories—offers immediate habitat protection gains and a visible pathway toward 30 × 30, while parallel efforts expand high-quality protection in open-ocean and deep-sea ecosystems and build enabling conditions elsewhere
Extrapolated degradation of optical systems at MGy levels due to radiation-induced refractive index change
No full textInternational audienc
Growth and Decay Kinetics of Radiation-Induced Attenuation in Bulk Optical Materials
No full textInternational audienc
