A multi-level stochastic collocation method for Schrödinger equations with a random potential

We propose and analyze a numerical method for time-dependent linear Schrödinger equations with uncertain parameters in both the potential and the initial data. The random parameters are discretized by stochastic collocation on a sparse grid, and the sample solutions in the nodes are approximated with the Strang splitting method. The computational work is reduced by a multi-level strategy, i.e. by combining information obtained from sample solutions computed on different refinement levels of the discretization. We prove new error bounds for the time discretization which take the finite regularity in the stochastic variable into account, and which are crucial to obtain convergence of the multi-level approach. The predicted cost savings of the multi-level stochastic collocation method are verified by numerical examples

Implementierung und Validierung eines Softwaremoduls für die Schädelsegmentierung aus CT- und DVT-Daten für Eingriffe in der Mund-, Kiefer- & Gesichtschirurgie

Im Rahmen eines Kooperationsprojektes zwischen dem Heidelberger Institut für Medizinische Informatik und Biometrie (IMBI) und der Mund- Kiefer und Gesichtschirurgie (MKG) des Universitätsklinikums Heidelberg soll ein MITK-Plugin für die Segmentierung von knöchernen Strukturen aus Schichtbilddaten der Computertomographie (CT), sowie der digitalen Volumentomographie (DVT) mit möglichst wenigen Nutzerinteraktionen entwickelt und evaluiert werden. Hierbei ist insbesondere eine hohe Segmentierungsqualität im Bereich des Kiefers und der Zähne relevant. Dabei erweisen sich Zahnspangen bzw. Zahnfüllungen als besondere Herausforderung. Die Arbeit, sowie das MITK-Plugin behandelt drei Aufgabenbereiche. Es handelt sich dabei um die Metallartefaktreduktion (MAR), Segmentierung und Oberflächenrekonstruktion. Die bildbasierte Artefaktreduktion kann auf CT-Datensätze entweder manuelle oder automatisch angewendet werden. Dabei stehen zwei verschiedene Methoden zur Auswahl. Es handelt sich dabei um die lineare Interpolation (LI) und die rohdatenfreien MAR (RFMAR). Ziel der Artefaktreduktion ist eine verbesserte 3D-Visualisierung. Dabei zeigen die Methoden stellenweise eine Verbesserung durch reduzierte schwarzer Schatten im Bereich der Metalle. Problematisch wirken sich neue Artefakte, welche durch die Reduktion enstehen, auf das Ergebnis der 3D-Visualierung aus. Für die Segmentierung sind zwei Verfahren implementiert worden. Es handelt sich dabei um ein eigenes automatisches Verfahren LCC (Largest Connected Component), und um einen Region Grower. Das automatische Verfahren ist hierbei robust gegenüber einer ungewollt segmentierten Patientenliege, hat aber den Nachteil dass unter Umständen nicht alle knöchernen Strukturen segmentiert werden. Für diesen Fall kann der Region Grower eingesetzt werden, welcher durch Benutzerinteraktion den Nachteil des LCC-Verfahrens ausgleicht. Die Verfahren zeigen im Bezug auf CT-Datensätze gute Ergebnisse. Durch den schlechten Knochenkontrast des verwendeten DVT-Gerätes müssen bei der Segmentierung der DVT-Datensätze Kompromisse eingegangen werden. Durch eine Histogramm-Analyse hat sich für die automatische Schwellwertbestimmung nach Otsu eine Mindestanzahl von drei Otsu-Schwellwerten ergeben. Weiterhin wurde das LCCVerfahren gegenüber einer Referenzsegmentierung eines MKG-Chirurgen evaluiert. Die Evaluierung zeigt, dass die Wahl zwischen drei und sechs Otsu-Schwellwerte keine signifikanten Auswirkungen auf die Genauigkeit der Segmentierung hat. Durch einen Kompromiss zwischen Laufzeit und Segmentierungsqualität wird die Verwendung von vier Otsu-Schwellwerten empfohlen

Simulationsstudie zu Konsolidierungsstrategien für das Bekleidungsmanagement der Bundeswehr

Having the right article in the right place at the right time is a logistical challenge – and can be vital. In this context, the Armed Forces of Germany (Bundeswehr) assess options to make the existing supply chain for protective attire more agile using online-shopping strategies. In this setting, the supply is internal to the organization: this allows for using of different consolidation strategies and applying customers’ risk aversion strategies to the supplier in using preventive sending strategies. To explore different delivery strategies, a high-level simulation model is proposed. Results show that with the applied strategies, the delivery of fitting articles on time can be improved: preventive sending can help to have the right article in place at the time needed, and consolidation helps to reduce the number of packages sent

Klotho controls the brain-immune system interface in the choroid plexus.

Located within the brain's ventricles, the choroid plexus produces cerebrospinal fluid and forms an important barrier between the central nervous system and the blood. For unknown reasons, the choroid plexus produces high levels of the protein klotho. Here, we show that these levels naturally decline with aging. Depleting klotho selectively from the choroid plexus via targeted viral vector-induced knockout in Klotho flox/flox mice increased the expression of multiple proinflammatory factors and triggered macrophage infiltration of this structure in young mice, simulating changes in unmanipulated old mice. Wild-type mice infected with the same Cre recombinase-expressing virus did not show such alterations. Experimental depletion of klotho from the choroid plexus enhanced microglial activation in the hippocampus after peripheral injection of mice with lipopolysaccharide. In primary cultures, klotho suppressed thioredoxin-interacting protein-dependent activation of the NLRP3 inflammasome in macrophages by enhancing fibroblast growth factor 23 signaling. We conclude that klotho functions as a gatekeeper at the interface between the brain and immune system in the choroid plexus. Klotho depletion in aging or disease may weaken this barrier and promote immune-mediated neuropathogenesis

Plumes in stellar convection zones

All numerical simulations of compressible convection reveal the presence of strong downwards directed flows. Thanks to helioseismology, such plumes have now been detected also at the top of the solar convection zone, on super- granular scales. Their properties may be crudely described by adopting Taylor's turbulent entrainment hypothesis, whose validity is well established under various conditions. Using this model, one finds that the strong density stratification does not prevent the plumes from traversing the whole convection zone, and that they carry upwards a net energy flux (Rieutord & Zahn 1995). They penetrate to some extent in the adjacent stable region, where they establish a nearly adiabatic stratification. These plumes have a strong impact on the dynamics of stellar convection zones, and they play probably a key role in the dynamo mechanism.Comment: Proceedings of the 14th Florida Workshop in Nonlinear Astronomy and Physics, "Astrophysical Turbulence and Convection", Eds. J.R. Buchler and H. Kandrup, to appear in the Annals of the New York Academy of Sciences (15 pages, 3 figures

Effects of Upper-Limb Exoskeletons Designed for Use in the Working Environment : A Literature Review

Introduction: Many employees report high physical strain from overhead work and resulting musculoskeletal disorders. The consequences of these conditions extend far beyond everyday working life and can severely limit the quality of life of those affected. One solution to this problem may be the use of upper-limb exoskeletons, which are supposed to relieve the shoulder joint in particular. The aim of this literature review was to provide an overview of the use and efficacy of exoskeletons for upper extremities in the working environment. Methods: A literature review was conducted using the PICO scheme and the PRISMA statement. To this end, a systematic search was performed in the PubMed, Web of Science and Scopus databases in May 2020 and updated in February 2022. The obtained studies were screened using previously defined inclusion and exclusion criteria and assessed for quality. Pertinent data were then extracted from the publications and analyzed with regard to type of exoskeleton used as well as efficacy of exoskeleton use. Results: 35 suitable studies were included in the review. 18 different exoskeletons were examined. The majority of the exoskeletons only supported the shoulder joint and were used to assist individuals working at or above shoulder level. The main focus of the studies was the reduction of muscle activity in the shoulder area. Indeed, 16 studies showed a reduced activity in the deltoid and trapezius muscles after exoskeleton use. Kinematically, a deviation of the movement behavior could be determined in some models. In addition, study participants reported perceived reduction in exertion and discomfort. Discussion: Exoskeletons for upper extremities may generate significant relief for the intended tasks, but the effects in the field (i.e., working environment) are less pronounced than in the laboratory setting. This may be due to the fact that not only overhead tasks but also secondary tasks have to be performed in the field. In addition, currently available exoskeletons do not seem to be suitable for all overhead workplaces and should always be assessed in the human-workplace context. Further studies in various settings are required that should also include more females and older people

The true price of external health effects from food consumption

Although global food consumption costs more in terms of impact on human life than money is spent on it, health costs have not been consistently quantified or included in food prices to date. In this paper, a method to determine the external health costs of nutrition and dietetics is developed by employing the cost-of-illness (COI) and true cost accounting (TCA) approaches. This is done exemplarily for the reference country Germany. The results show that 601.50 € per capita and 50.38 billion € in total external health costs are incurred annually due to nutrition. Overall, most costs are accrued through excessive meat consumption (32.56% of costs), deficient whole grain intake (15.42% of costs), and insufficient uptake of legumes (10.19% of costs). Comparing the external health costs with the external environmental costs in Germany, it can be seen that of the total annual costs of around 153.86 billion €, 67.26% originate from environmental impacts and 32.74% from impacts on human life. In order to achieve the 17 Sustainable Development Goals and to increase family as well as public health, there is a need to internalise these external costs into actual food prices

HTPheno: An image analysis pipeline for high-throughput plant phenotyping

<p>Abstract</p> <p>Background</p> <p>In the last few years high-throughput analysis methods have become state-of-the-art in the life sciences. One of the latest developments is automated greenhouse systems for high-throughput plant phenotyping. Such systems allow the non-destructive screening of plants over a period of time by means of image acquisition techniques. During such screening different images of each plant are recorded and must be analysed by applying sophisticated image analysis algorithms.</p> <p>Results</p> <p>This paper presents an image analysis pipeline (HTPheno) for high-throughput plant phenotyping. HTPheno is implemented as a plugin for ImageJ, an open source image processing software. It provides the possibility to analyse colour images of plants which are taken in two different views (top view and side view) during a screening. Within the analysis different phenotypical parameters for each plant such as height, width and projected shoot area of the plants are calculated for the duration of the screening. HTPheno is applied to analyse two barley cultivars.</p> <p>Conclusions</p> <p>HTPheno, an open source image analysis pipeline, supplies a flexible and adaptable ImageJ plugin which can be used for automated image analysis in high-throughput plant phenotyping and therefore to derive new biological insights, such as determination of fitness.</p