Glass cliffs: firms appoint female executives in times of crisis as a signal of change to investors

The glass cliff hypothesis suggests that female executives are more likely to be put in charge when the company is already in a crisis. Yet research has found mixed evidence for the existence of glass cliffs in the business world. Max Reinwald, Johannes Zaia, and Florian Kunze analyse 26,156 executive appointments of public companies in the United States between 2000 and 2016 and show that crisis firms are about 50% more likely to appoint a female executive than noncrisis firms to send a signal of change to their investors

Stretch controlled shading capabilities of special elastomeric silicone films

A hitherto unexploited effect: the reversible stretch-induced change of translucency and transparency of certain silicone materials is experimentally investigated with regard to an application in a new type of shading system for biaxial bent, free-form building envelopes. In a first step the silicone raw materials showing the effect are processed into membrane shape and the stretch-dependent optical characteristics of the silicone film samples are examined. Shading effects are measured during cyclic and long term uniaxial tension tests. For multiaxial loading conditions, as appearing in planar biaxial tension tests with cross shaped specimens and bulge tests with inflated circular specimens, optical inhomogeneity effects due to locally varying elongations are documented. Further results concerning a variable transparency depending on the distance of the observer and an object behind the membrane are discussed. A conceptual application of the materials into translucent facades for shading purposes is presented. The closed cavity concept of planar stretched films located between window screens and the implementation of silicone films as inflatable shading structures are discussed. Furthermore, the advantages of silicone films in these kinds of cladding types are pointed out, as typical problems i.e. fogging and high-temperature stability pose no major issue

LROC-PANGU-GAN: closing the simulation gap in learning crater segmentation with planetary simulators

It is critical for probes landing on foreign planetary bodies to be able to robustly identify and avoid hazards – as, for example, steep cliffs or deep craters can pose significant risks to a probe’s landing and operational success. Recent applications of deep learning to this problem show promising results. These models are, however, often learned with explicit supervision over annotated datasets. These human-labelled crater databases, such as from the Lunar Reconnaissance Orbiter Camera (LROC), may lack in consistency and quality, undermining model performance – as incomplete and/or inaccurate labels introduce noise into the supervisory signal, which encourages the model to learn incorrect associations and results in the model making unreliable predictions. Physics-based simulators, such as the Planet and Asteroid Natural Scene Generation Utility, have, in contrast, perfect ground truth, as the internal state that they use to render scenes is known with exactness. However, they introduce a serious simulation-to-real domain gap – because of fundamental differences between the simulated environment and the real-world arising from modelling assumptions, unaccounted for physical interactions, environmental variability, etc. Therefore, models trained on their outputs suffer when deployed in the face of realism they have not encountered in their training data distributions. In this paper, we therefore introduce a system to close this “realism” gap while retaining label fidelity. We train a CycleGAN model to synthesise LROC from Planet and Asteroid Natural Scene Generation Utility (PANGU) images. We show that these improve the training of a downstream crater segmentation network, with segmentation performance on a test set of real LROC images improved as compared to using only simulated PANGU images. This will in the future allow researchers to more robustly test in-the-loop autonomous systems when tested in simulators such as PANGU

Fast 3D YOLOv3 based standard plane regression of vertebral bodies in intra-operative CBCT volumes

Purpose Mobile C-arm systems represent the standard imaging devices within the field of spine surgery. In addition to 2D imaging, they allow for 3D scans while preserving unrestricted patient access. For viewing, the acquired volumes are adjusted such that their anatomical standard planes align with the axes of the viewing modality. This difficult and time-consuming step is currently performed manually by the leading surgeon. This process is automatized within this work to improve the usability of C-arm systems. Thereby, the spinal region consisting of multiple vertebrae and the standard planes of all vertebrae being of interest to the surgeon need to be taken into account. Approach An object detection algorithm based on the you only look once version 3 architecture, adapted to 3D inputs, is compared with a segmentation-based approach employing a 3D U-Net. Both algorithms are trained on a dataset of 440 and tested on 218 spinal volumes. Results Although the detection-based algorithm is slightly inferior concerning the detection (91% versus 97% accuracy), localization (1.26 mm versus 0.74 mm error) and alignment accuracy (5.00 deg versus 4.73 deg error), it outperforms the segmentation-based one in terms of speed (5 s versus 38 s). Conclusions Both algorithms show similar good results. However, the speed gain of the detection-based algorithm, resulting in a run time of 5 s, makes it more suitable for usage in an intra-operative scenario

The 2017 Update of the German Clinical Guideline on Epidemiology, Diagnostics, Therapy, Prevention, and Management of Uncomplicated Urinary Tract Infections in Adult Patients: Part 1

Objectives: We aimed to update the 2010 evidence- and consensus-based national clinical guideline on the diagnosis and management of uncomplicated urinary tract infections (UTIs) in adult patients. Materials and Methods: An interdisciplinary group consisting of 17 representatives of 12 medical societies and a patient representative was formed. Systematic literature searches were conducted in MEDLINE, ­EMBASE, and the Cochrane Library to identify literature published in 2010–2015. Results: We provide 75 recommendations and 68 statements in the updated evidence- and consensus-based national clinical guideline. The diagnostics part covers practical recommendations on cystitis and pyelonephritis for each defined patient group. Clinical examinations, as well as laboratory testing and microbiological pathogen assessment, are addressed. Conclusion: In accordance with the global antibiotic stewardship initiative and considering new insights in scientific research, we updated our German clinical UTI guideline to promote a responsible antibiotic use and to give clear hands-on recommendations for the diagnosis and management of UTIs in adults in Germany for healthcare providers and patients

The 2017 Update of the German Clinical Guideline on Epidemiology, Diagnostics, Therapy, Prevention, and Management of Uncomplicated Urinary Tract Infections in Adult Patients. Part II: Therapy and Prevention

Background: We aimed to update the 2010 evidence- and consensus-based national clinical guideline on the diagnosis and management of uncomplicated urinary tract infections (UTIs) in adult patients. Results are published in 2 parts. Part 1 covers methods, the definition of patient groups, and diagnostics. This second publication focuses on treatment of acute episodes of cystitis and pyelonephritis as well as on prophylaxis of recurrent UTIs. Materials and Methods: An interdisciplinary group consisting of 17 representatives of 12 medical societies and a patient representative was formed. Systematic literature searches were conducted in MEDLINE, EMBASE, and the Cochrane Library to identify literature published in 2010–2015. Results: For the treatment of acute uncomplicated cystitis (AUC), fosfomycin-trometamol, nitrofurantoin, nitroxoline, pivmecillinam, and trimethoprim (depending on the local rate of resistance) are all equally recommended. Cotrimoxazole, fluoroquinolones, and cephalosporins are not recommended as antibiotics of first choice, for concern of an unfavorable impact on the microbiome. Mild to moderate uncomplicated pyelonephritis should be treated with oral cefpodoxime, ceftibuten, ciprofloxacin, or levofloxacin. For AUC with mild to moderate symptoms, instead of antibiotics symptomatic treatment alone may be considered depending on patient preference after discussing adverse events and outcomes. Primarily non-antibiotic options are recommended for prophylaxis of recurrent urinary tract infection. Conclusion: In accordance with the global antibiotic stewardship initiative and considering new insights in scientific research, we updated our German clinical UTI guideline to promote a responsible antibiotic use and to give clear hands-on recommendations for the diagnosis and management of UTIs in adults in Germany for healthcare providers and patients

Multi-Stage Platform for (Semi-)Automatic Planning in Reconstructive Orthopedic Surgery

Intricate lesions of the musculoskeletal system require reconstructive orthopedic surgery to restore the correct biomechanics. Careful pre-operative planning of the surgical steps on 2D image data is an essential tool to increase the precision and safety of these operations. However, the plan’s effectiveness in the intra-operative workflow is challenged by unpredictable patient and device positioning and complex registration protocols. Here, we develop and analyze a multi-stage algorithm that combines deep learning-based anatomical feature detection and geometric post-processing to enable accurate pre- and intra-operative surgery planning on 2D X-ray images. The algorithm allows granular control over each element of the planning geometry, enabling real-time adjustments directly in the operating room (OR). In the method evaluation of three ligament reconstruction tasks effect on the knee joint, we found high spatial precision in drilling point localization (ε<2.9mm) and low angulation errors for k-wire instrumentation (ε<0.75∘) on 38 diagnostic radiographs. Comparable precision was demonstrated in 15 complex intra-operative trauma cases suffering from strong implant overlap and multi-anatomy exposure. Furthermore, we found that the diverse feature detection tasks can be efficiently solved with a multi-task network topology, improving precision over the single-task case. Our platform will help overcome the limitations of current clinical practice and foster surgical plan generation and adjustment directly in the OR, ultimately motivating the development of novel 2D planning guidelines

Material models for highly dynamic metal forming processes

Nowadays, industrial processes like sheet metal bending or punching are performed with high precision. Further optimizations are only possible by simulation and appropriate material models and parameters. Goal of this work is to find a material model suitable for both, bending and punching processes, including the effects of plasticity at high strains and strain rates. The models are calibrated by material tests like tension or torsion tests