Resolution of the atmospheric model matters for the Northern Hemisphere Mid-Holocene climate

Highlights: • Temperature anomalies for the Mid-Holocene compared to preindustrial are significantly different in the low- and high-resolution versions of the atmospheric model ECHAM5 • For summer, shortwave cloud radiative forcing emerges as an important factor. • For boreal winter, differences are mainly related to circulation changes. • Anomaly differences are regionally as large as the mid-Holocene minus preindustrial temperature signals. Abstract: This study evaluates the dependence of simulated surface air temperatures on model resolution and orography for the mid-Holocene. Sensitivity experiments with the atmospheric general circulation model ECHAM5 are performed with low (∼3.75°, 19 vertical levels) and high (∼1.1°, 31 vertical levels) resolution. Results are compared to the respective preindustrial runs. It is found that the large-scale temperature anomalies for the mid-Holocene (compared to preindustrial) are significantly different in the low- and high-resolution versions. For boreal winter, differences are mainly related to circulation changes caused by the response to thermal forcing in conjunction with orographic resolution. For summer, shortwave cloud radiative forcing emerges as an important factor. The anomaly differences (low minus high resolution version) in the Northern Hemisphere are regionally as large as the anomalous mid-Holocene temperature signals. Furthermore, they depend on the applied surface boundary conditions. We conclude that the resolution matters for the Northern Hemisphere response in mid-Holocene simulations, which should be taken into account in model-model and data-model comparisons

Hierarchical Time-Optimal Planning for Multi-Vehicle Racing

This paper presents a hierarchical planning algorithm for racing with multiple opponents. The two-stage approach consists of a high-level behavioral planning step and a low-level optimization step. By combining discrete and continuous planning methods, our algorithm encourages global time optimality without being limited by coarse discretization. In the behavioral planning step, the fastest behavior is determined with a low-resolution spatio-temporal visibility graph. Based on the selected behavior, we calculate maneuver envelopes that are subsequently applied as constraints in a time-optimal control problem. The performance of our method is comparable to a parallel approach that selects the fastest trajectory from multiple optimizations with different behavior classes. However, our algorithm can be executed on a single core. This significantly reduces computational requirements, especially when multiple opponents are involved. Therefore, the proposed method is an efficient and practical solution for real-time multi-vehicle racing scenarios.Comment: 6 pages, accepted to be published as part of the 26th IEEE International Conference on Intelligent Transportation Systems (ITSC 2023), Bilbao, Bizkaia, Spain, September 24-28, 202

Online Time-Optimal Trajectory Planning on Three-Dimensional Race Tracks

We propose an online planning approach for racing that generates the time-optimal trajectory for the upcoming track section. The resulting trajectory takes the current vehicle state, effects caused by \acl{3D} track geometries, and speed limits dictated by the race rules into account. In each planning step, an optimal control problem is solved, making a quasi-steady-state assumption with a point mass model constrained by gg-diagrams. For its online applicability, we propose an efficient representation of the gg-diagrams and identify negligible terms to reduce the computational effort. We demonstrate that the online planning approach can reproduce the lap times of an offline-generated racing line during single vehicle racing. Moreover, it finds a new time-optimal solution when a deviation from the original racing line is necessary, e.g., during an overtaking maneuver. Motivated by the application in a rule-based race, we also consider the scenario of a speed limit lower than the current vehicle velocity. We introduce an initializable slack variable to generate feasible trajectories despite the constraint violation while reducing the velocity to comply with the rules.Comment: 8 pages, accepted to be published as part of the 34th IEEE Intelligent Vehicles Symposium (IV), Anchorage, Alaska, USA, June 4-7, 202

Pegaptanib sodium treatment in neovascular age-related macular degeneration: clinical experience in Germany

Nikolaus Feucht, Huebner Matthias, Chris P Lohmann, Mathias MaierAugenklinik rechts der Isar, Technical University Munich, GermanyBackground: The VEGF Inhibition Study In Ocular Neovascularisation (VISION) reported the efficacy of intravitreal (ITV) vascular endothelial growth factor (VEGF) inhibition with pegaptanib sodium (Macugen®) for the treatment of neovascular age-related macular degeneration (AMD). This paper reports clinical experience with pegaptanib sodium for the treatment of occult or minimally classic choroidal neovascularization (CNV) due to AMD.Material and methods: The study included 50 eyes (in 49 patients) with either occult CNV or minimally classic CNV secondary to neovascular AMD who were not eligible for photodynamic therapy (PDT). Study data were analyzed retrospectively. During the 6-month study, patients were administered an average 2.74 injections of 0.3 mg ITV pegaptanib sodium. Angiography and optical coherence tomography (OCT) examinations were carried out and intraocular pressure (IOP) and visual acuity (VA) were measured at baseline, at 3 months and at 6 months. An eye examination was performed and VA was measured the 2 days following treatment and then again at weeks 4–6, and at 3 and 6 months. OCT, VA, and IOP were also assessed at 1 month.Results: ITV pegaptanib sodium was well tolerated and no treatment complications arose. Mean VA was measured as: 0.37 ± 0.24 at baseline; 0.37 ± 0.25 at 1 month; 0.37 ± 0.25 at 3 months and 0.40 ± 0.26 at 6 months. VA was stabilized in approximately 90% of eyes treated with pegaptanib sodium. OCT examination showed a minimal change in central retinal thickness (CRT) during the course of the study, from 251.19 µm at baseline to 251.63 µm at 6 months. No elevation in IOP was measured during treatment at 4–6 months in patients receiving pegaptanib sodium.Conclusions: ITV therapy with pegaptanib sodium for occult and minimally classic CNV secondary to neovascular AMD offered good efficacy with a favorable adverse events profile. The majority of patients showed stabilization in all assessed parameters. In clinical practice, careful consideration should be given to the use of nonselective VEGF inhibition in patients with a high cardiovascular risk profile or in those with a history of thromboembolic events.Keywords: Intravitreal (ITV) injection, age-related macular degeneration (AMD), choroidal neovascularization (CNV), anti-VEGF therapy, pegaptanib sodiu

Detoxification Strategy of Epoxide Hydrolase

The human microsomal epoxide hydrolase, a single enzyme, has to detoxify a broad range of structurally diverse, potentially genotoxic epoxides that are formed in the course of xenobiotic metabolism. The enzyme has developed a unique strategy to combine a broad substrate specificity with a high detoxification efficacy, by immediately trapping the reactive compounds as covalent intermediates and by being expressed at high levels for high trapping capacity. Computer simulation and experimental data as well as existing epidemiologic studies reveal this detoxification strategy as the mechanistic basis for a threshold in the tumorigenesis of mutagenic carcinogens

Radiomics in neuro-oncological clinical trials

The development of clinical trials has led to substantial improvements in the prevention and treatment of many diseases, including brain cancer. Advances in medicine, such as improved surgical techniques, the development of new drugs and devices, the use of statistical methods in research, and the development of codes of ethics, have considerably influenced the way clinical trials are conducted today. In addition, methods from the broad field of artificial intelligence, such as radiomics, have the potential to considerably affect clinical trials and clinical practice in the future. Radiomics is a method to extract undiscovered features from routinely acquired imaging data that can neither be captured by means of human perception nor conventional image analysis. In patients with brain cancer, radiomics has shown its potential for the non-invasive identification of prognostic biomarkers, automated response assessment, and differentiation between treatment-related changes from tumour progression. Despite promising results, radiomics is not yet established in routine clinical practice nor in clinical trials. In this Viewpoint, the European Organization for Research and Treatment of Cancer Brain Tumour Group summarises the current status of radiomics, discusses its potential and limitations, envisions its future role in clinical trials in neuro-oncology, and provides guidance on how to address the challenges in radiomics

Experimental analysis on the influence of freeform bending on Barkhausen noise for steel tubes

Freeform bending with a movable die makes it possible to bend complex structures and seamless radii without changing the bending tools. Currently, most research focuses on minimizing the geometrical deviations without considering the mechanical properties of the bent tubes. A previous work showed, that the geometry can be decoupled from the mechanical properties with non-tangential bending [1]. The implementation of a soft sensor based on ultrasonic contact impedance measurements (UCI) of the property-controlled freeform bending has also been examined [2], as well as a structure for closed-loop control based on material properties [3]. The present work deals with a micro-magnetic sensor and Barkhausen noise (BHN) and investigates its suitability for the closed-loop control. For this purpose, different processing routes for freeform-bent steel tubes are experimentally investigated by their characteristic BHN. In addition to an existing simulation model, a data basis for the impact of freeform bending parameters is built to extend the existing model of a property-based closed-loop control

Abrupt shift of the Atlantic Ocean circulation induced by atmospheric blocking

Fram Strait sea ice export from the Arctic represents a key source of fresh water for the North Atlantic. Although it may have strong influence on the ocean circulation, its causes and consequences are not yet fully understood. Using a global ocean-sea ice model with an increased resolution over the Arctic, here it is shown that enhanced blocking activity over Greenland during the 1962-1966 period favors sea ice accumulation in the Arctic, whereas during the 1967-1971 period, when this blocking configuration is weak, the associated intense sea ice export trough Fram Strait reduces the Labrador Sea salinity and weakens the AMOC. These results indicate that AMOC shifts toward weak states, as the one emphasized here in the 1970s, may be induced by rapid sea ice flushes from the Arctic, after periods of enhanced blocking activity over Greenland. They imply also that an important part of the atmosphere-ocean dynamics at mid- and high latitudes requires a proper representation of the Fram Strait and associated sea ice transport as well as synoptic scale variability such as atmospheric blocking, which is a challenge for current coupled climate models

Linkages between atmospheric blocking, sea ice export through Fram Strait and the Atlantic Meridional Overturning Circulation

As a key persistent component of the atmospheric dynamics, the North Atlantic blocking activity has been linked to extreme climatic phenomena in the European sector. It has also been linked to Atlantic multidecadal ocean variability, but its potential links to rapid oceanic changes have not been investigated. Using a global ocean-sea ice model forced with atmospheric reanalysis data, here it is shown that the 1962–1966 period of enhanced blocking activity over Greenland resulted in anomalous sea ice accumulation in the Arctic and ended with a sea ice flush from the Arctic into the North Atlantic Ocean through Fram Strait. This event induced a significant decrease of Labrador Sea water surface salinity and an abrupt weakening of the Atlantic Meridional Overturning Circulation (AMOC) during the 1970s. These results have implications for the prediction of rapid AMOC changes and indicate that an important part of the atmosphere-ocean dynamics at mid- and high latitudes requires a proper representation of the Fram Strait sea ice transport and of the synoptic scale variability such as atmospheric blocking, which is a challenge for current coupled climate models