Stochastic Parameterization Toward a New View of Weather and Climate Models

Peer reviewe

Do Knobs have Character? Exploring Diversity in Users ’ Inferences

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Solid-state extrusion of nascent disentangled ultra-high molecular weight polyethylene

Ultra-high molecular weight polyethylene (UHMWPE) stands out as the preferred material across a wide spectrum of demanding applications, thanks to its remarkable mechanical, chemical and physical attributes. Nevertheless, processing UHMWPE can be an arduous and time-consuming endeavor. Traditional melt-processing techniques, commonly employed for polymers, prove impractical due to the exceedingly high viscosity of the melt that follows from the highly entangled macromolecular chains. Several methods are known to lower the entanglement density of UHMWPE, such as crystallization from a semidilute solution or direct polymerization, resulting in a less interconnected polymer structure. Unfortunately, even with low-entangled UHMWPE, melt processing remains unviable because of the rapid re-entanglement of polymer chains upon melting. However, these low-entangled UHMWPE materials can still be effectively processed in the solid state, a technique employed in the production of high-performance UHMWPE fibers and tapes, currently the only two feasible geometries. This research reports the development of a solid-state extrusion method for nascent low-entangled powder, centering on manipulating the surface energy of the interior wall materials within the extruder and die. Ordinary steel dies proved ineffective for solid-state extrusion, as they generated excessive friction between the die and UHMWPE, resulting in a rapidly escalating extrusion pressure. However, utilizing dies constructed from temperature-resistant polymers allowed for extrusion at a consistent pressure without the need for lubricating agents. We demonstrate the practicality of the developed solid-state extrusion method by fabricating UHMWPE monofilaments and tubes, showcasing its potential in expanding the range of producible UHMWPE geometries. Additionally, a first evaluation of the influence of processing conditions and the entanglement density of the reactor powder used on extrudability, and the properties of the resulting components is presented.Highlights A process for the solid-state extrusion of UHMWPE is developed. UHMWPE processing with higher design flexibility than current industrial standards. UHMWPE processing with higher throughput than current industrial standards. Contrary to previous techniques no lubricating agent or co-extrudate is used.ISSN:0032-3888ISSN:1548-263

Evaluation des Praktikums »Psychosomatik und Psychotherapie« mit standardisierten Patienten

Doering S, Schneider G, Burgmer M, et al. Evaluation des Praktikums »Psychosomatik und Psychotherapie« mit standardisierten Patienten. Zeitschrift für Psychosomatische Medizin und Psychotherapie. 2010;56(4):385-398

Early Stabilization Does Not Increase Complication Rates in Acetabular Fractures of the Elderly: A Retrospective Analysis from the German Pelvis Registry

Background: The incidence of acetabular fractures in geriatric patients has increased. Although there are strong data supporting the early operative treatment of hip fractures in geriatric patients, the optimal timing for acetabular fractures remains unclear and for several reasons, delayed treatment after trauma is common. Methods: A retrospective analysis of the German Pelvis Registry between 2008 and 2017 was performed. Ultimately, 665 patients with fractures of the anterior column or anterior column and posterior hemitransverse were enrolled. Patients above and below 65 years of age with these fracture types were analyzed regarding surgery day (within 48 hours, between 2 and 4 days, after 4 days), complication rate, reduction quality, and hospital stay. Results: The complication rate of the geriatric group was twice as high as that of younger patients; however, this finding was independent of the timing of surgery. Reduction quality and hospital stay were independent of surgical timing. Conclusions: In contrast to other fracture types, such as proximal femur fractures, the timing of surgery for acetabular fractures does not have a significant impact on the patient’s outcome. The optimal time for surgery cannot be determined using the current data. However, as expected, there is a significantly higher risk for postoperative complications in the geriatric population

Tailored bimodal ultra-high molecular weight polyethylene particles

A single molecular catalyst system supported on MgCl2 has been developed and combined with a simple two-stage fed-batch polymerization process to produce tailored bimodal polyethylene reactor blend particles of UHMWPE. By varying and controlling the process conditions in the first stage and second stage, bimodal HMWPE:UHMWPE reactor particles are obtained with independent control over the individual molar masses, the mass ratio of the HMWPE and UHMWPE components, and the reactor powder particle size. This allows multidimensional control over the individual UHMWPE reactor particle properties

An Approach for Asynchronous Awareness Support in Collaborative Non-Linear Storytelling

Workspace awareness support is mandatory for group support systems. It allows users not only to follow actions of others, but to understand and respond to any changes others make to the workspace. In this paper, we present a novel approach for asynchronous awareness support by offering different filters to retrieve relevant awareness information and visualizing the evolution of the shared artifact. We illustrate our approach with a tool for collaborative non-linear storytelling in which users can jointly create a story graph of interconnected audio files. Such a story graph is an example for a non-linear story. We describe the development of a prototype that visualizes how the collaborative story has evolved over time. We evaluate our approach for asynchronous awareness support in an experiment with 40 participants exploring story graphs of different complexity. The evaluation results show that our visualization approach helps group members to assess who has modified the shared story, how it was modified, what exactly has been modified, and when it has been modified.Multi Actor SystemsTechnology, Policy and Managemen

Profiling physical activity motivation based on self-determination theory: a cluster analysis approach

In order to promote physical activity uptake and maintenance in individuals who do not comply with physical activity guidelines, it is important to increase our understanding of physical activity motivation among this group. The present study aimed to examine motivational profiles in a large sample of adults who do not comply with physical activity guidelines.The sample for this study consisted of 2473 individuals (31.4% male; age 44.6?12.9). In order to generate motivational profiles based on motivational regulation, a cluster analysis was conducted. One-way analyses of variance were then used to compare the clusters in terms of demographics, physical activity level, motivation to be active and subjective experience while being active.Three motivational clusters were derived based on motivational regulation scores: a low motivation cluster, a controlled motivation cluster and an autonomous motivation cluster. These clusters differed significantly from each other with respect to physical activity behavior, motivation to be active and subjective experience while being active. Overall, the autonomous motivation cluster displayed more favorable characteristics compared to the other two clusters.The results of this study provide additional support for the importance of autonomous motivation in the context of physical activity behavior. The three derived clusters may be relevant in the context of physical activity interventions as individuals within the different clusters might benefit most from different intervention approaches. In addition, this study shows that cluster analysis is a useful method for differentiating between motivational profiles in large groups of individuals who do not comply with physical activity guidelines