233 research outputs found

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

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    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

    Deep Learning Strategies for Industrial Surface Defect Detection Systems

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    Deep learning methods have proven to outperform traditional computer vision methods in various areas of image processing. However, the application of deep learning in industrial surface defect detection systems is challenging due to the insufficient amount of training data, the expensive data generation process, the small size, and the rare occurrence of surface defects. From literature and a polymer products manufacturing use case, we identify design requirements which reflect the aforementioned challenges. Addressing these, we conceptualize design principles and features informed by deep learning research. Finally, we instantiate and evaluate the gained design knowledge in the form of actionable guidelines and strategies based on an industrial surface defect detection use case. This article, therefore, contributes to academia as well as practice by (1) systematically identifying challenges for the industrial application of deep learning-based surface defect detection, (2) strategies to overcome these, and (3) an experimental case study assessing the strategies' applicability and usefulness

    One-dimensional arrangements of metal atoms in transition metal carbonyl complexes of mixed main group metal alkoxides

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    Mixed metal alkoxides containing main group elements with ns2 electron configurations of the general formula M(OtBu)3M\u27 (M = In, Tl; M\u27 = Ge, Sn, Pb), M\u27(OtBu)3M(OtBu)3M\u27 (M = divalent metal atom, M\u27 = Ge, Sn) and (OtBu)M\u27(OtBu)2M(OtBu)2M\u27(OtBu) (M = Co, Ni; M\u27 = Ge, Sn) can be reacted with simple metal carbonyls. The products obtained are composed of a one-dimensional array of metal atoms held together by direct metal-metal bonds or by bridging alkoxide groups. The following compounds have been isolated and characterized by IR and NMR spectroscopy and X-ray diffraction (M\u27 = Ge, Sn, Pb; M = In, Tl; MT = transition metal): M\u27(OtBu)3M-MT(CO)n, (CO)nMT-M(OtBu)3M\u27-MT(CO)n, M\u27(OtBu)3M-MT(CO)nM(OtBu)3M\u27, (CO)nMT-M\u27(OtBu)3M(OtBu)3M\u27-MT(CO)n, (CO)nMT-M\u27[OtBu](OtBu)2M(OtBu)2M(OtBu)2[OtBu]M\u27-MT(CO)n and (CO)nMT-M\u27(OtBu)3M-MT(CO)nM(OtBu)3M\u27-MT(CO)n. In addition, an oligomeric species of the general formula [Sn(OtBu)3In-Mo(CO)4]n-Sn(OtBu)3In-Mo(CO)5 with n ~ 9, 10 has been isolated

    Hidden localization motifs: naturally occurring peroxisomal targeting signals in non-peroxisomal proteins

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    BACKGROUND: Can sequence segments coding for subcellular targeting or for posttranslational modifications occur in proteins that are not substrates in either of these processes? Although considerable effort has been invested in achieving low false-positive prediction rates, even accurate sequence-analysis tools for the recognition of these motifs generate a small but noticeable number of protein hits that lack the appropriate biological context but cannot be rationalized as false positives. RESULTS: We show that the carboxyl termini of a set of definitely non-peroxisomal proteins with predicted peroxisomal targeting signals interact with the peroxisomal matrix protein receptor peroxin 5 (PEX5) in a yeast two-hybrid test. Moreover, we show that examples of these proteins - chicken lysozyme, human tyrosinase and the yeast mitochondrial ribosomal protein L2 (encoded by MRP7) - are imported into peroxisomes in vivo if their original sorting signals are disguised. We also show that even prokaryotic proteins can contain peroxisomal targeting sequences. CONCLUSIONS: Thus, functional localization signals can evolve in unrelated protein sequences as a result of neutral mutations, and subcellular targeting is hierarchically organized, with signal accessibility playing a decisive role. The occurrence of silent functional motifs in unrelated proteins is important for the development of sequence-based function prediction tools and the interpretation of their results. Silent functional signals have the potential to acquire importance in future evolutionary scenarios and in pathological conditions

    Design, Manufacturing, and Characterization of Thin, Core-Free, Rolled Dielectric Elastomer Actuators

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    In this work, we develop a coreless rolled dielectric elastomer actuator (CORDEA) to be used as artificial muscles in soft robotic structures. The new CORDEA concept is based on a 50 µm silicone film with screen-printed electrodes made of carbon black suspended in polydimethylsiloxane. Two printed silicone films are stacked together and then tightly rolled in a spiral-like structure. Readily available off-the-shelf components are used to implement both electrical and mechanical contacts. A novel manufacturing process is developed to enable the production of rolled actuators without a hollow core, with a focus on simplicity and reliability. In this way, actuator systems with high energy density can be effectively achieved. After presenting the design, an experimental evaluation of the CORDEA electromechanical behavior is performed. Finally, actuator experiments in which the CORDEA is pre-loaded with a mass load and subsequently subject to cycling voltage are illustrated, and the resulting performance is discussed

    Predicting drug metabolism: experiment and/or computation?

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    Drug metabolism can produce metabolites with physicochemical and pharmacological properties that differ substantially from those of the parent drug, and consequently has important implications for both drug safety and efficacy. To reduce the risk of costly clinical-stage attrition due to the metabolic characteristics of drug candidates, there is a need for efficient and reliable ways to predict drug metabolism in vitro, in silico and in vivo. In this Perspective, we provide an overview of the state of the art of experimental and computational approaches for investigating drug metabolism. We highlight the scope and limitations of these methods, and indicate strategies to harvest the synergies that result from combining measurement and prediction of drug metabolism.This is the accepted manuscript of a paper published in Nature Reviews Drug Discovery (Kirchmair J, Göller AH, Lang D, Kunze J, Testa B, Wilson ID, Glen RC, Schneider G, Nature Reviews Drug Discovery, 2015, 14, 387–404, doi:10.1038/nrd4581). The final version is available at http://dx.doi.org/10.1038/nrd458

    One-dimensional arrangements of metal atoms in transition metal carbonyl complexes of mixed main group metal alkoxides

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    Mixed metal alkoxides containing main group elements with ns2 electron configurations of the general formula M(OtBu)3M' (M = In, Tl; M' = Ge, Sn, Pb), M'(OtBu)3M(OtBu)3M' (M = divalent metal atom, M' = Ge, Sn) and (OtBu)M'(OtBu)2M(OtBu)2M'(OtBu) (M = Co, Ni; M' = Ge, Sn) can be reacted with simple metal carbonyls. The products obtained are composed of a one-dimensional array of metal atoms held together by direct metal-metal bonds or by bridging alkoxide groups. The following compounds have been isolated and characterized by IR and NMR spectroscopy and X-ray diffraction (M' = Ge, Sn, Pb; M = In, Tl; MT = transition metal): M'(OtBu)3M-MT(CO)n, (CO)nMT-M(OtBu)3M'-MT(CO)n, M'(OtBu)3M-MT(CO)nM(OtBu)3M', (CO)nMT-M'(OtBu)3M(OtBu)3M'-MT(CO)n, (CO)nMT-M'[OtBu](OtBu)2M(OtBu)2M(OtBu)2[OtBu]M'-MT(CO)n and (CO)nMT-M'(OtBu)3M-MT(CO)nM(OtBu)3M'-MT(CO)n. In addition, an oligomeric species of the general formula [Sn(OtBu)3In-Mo(CO)4]n-Sn(OtBu)3In-Mo(CO)5 with n ~ 9, 10 has been isolated

    Technical assistance to assess the potential of renewable liquid and gaseous transport fuels of non-biological origin (RFNBOs) as well as recycled carbon fuels (RCFs), to establish a methodology to determine the share of renewable energy from RFNBOs as well as to develop a framework on additionality in the transport sector

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    This report is a summary of the work conducted in Task 1 of the technical assistance to assess the potential of renewable fuels of non-biological origin (RFNBOs) and recycled carbon fuels (RCFs) to establish a methodology to determine the share of renewable energy from RFNBOs as well as to develop a framework on additionality in the transport sector. The goal of Task 1 within the entire project was the assessment of the deployment potential of RFNBOs and RCFs over the period from 2020 to 2050 in the EU transport sector. All relevant transport sub-sectors and modalities are considered: road transport, maritime and inland shipping, aviation, and railway. Furthermore, the competition for RFNBOs and RCFs between the transport sectors and other sectors and applications of RFNBOs is considered. A central result is the potential gross final consumption of RFNBOs and RCFs that would count towards the RES target in the transport sector. In addition, the needed resources and the arising costs for this deployment as well as the impacts on greenhouse gas emissions and local environments are analyzed. Finally, barriers to the deployment and options to overcome these are outlined

    LuFo V-3 CORINNE - Schlussbericht Comfort Of Ride Improved eNgiNEering -Komfortverbesserung im niederfrequenten Bereich für Hubschrauber

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    Hubschrauberpiloten sind auch in aktuellen Hubschraubermustern einem hohen Vibrationsniveau ausgesetzt. Diese Vibrationen können negative Auswirkungen auf die Gesundheit und die Leistungsfähigkeit der Hubschrauberbesatzung und der Passagiere haben. Insbesondere Schwingungen im niederfrequenten Bereich standen dabei im Fokus des Verbundprojekts CORINNE. Diese Vibrationen werden u.a. durch Turbulenz angeregt und wirken verstärkt durch Flugregelungssysteme und Autopiloten auf die flugmechanischen Moden des Hubschraubers. Im DLR-Beitrag von CORINNE wurde hauptsächlich an drei Teilaspekten zur Reduzierung der niederfrequenten Vibrationen geforscht. Erstens wurde ein Turbulenzmodell für den Forschungshubschrauber ACT/FHS auf Basis von Flugversuchsdaten erstellt und validiert. Dieses sog. CETI-Modell wurde auch auf andere Hubschraubermuster skaliert. Zusätzlich ist es im ACT/FHS und AVES Simulator verfügbar, um Turbulenz zu simulieren. Zweitens wurde das Simulationsverfahren UPM in das Hubschraubersimulationsmodell von Airbus Helicopters integriert und validiert. Mit diesem Simulationsverfahren können flugmechanische Stabilitätseigenschaften wie die der Phygoide und des Dutch Rolls genauer vorhersagt und die Simulationsgüte im Manöverflug gesteigert werden. Drittens wurde ein Beobachter für die longitudinalen und lateralen Rotormastmomente des ACT/FHS auf Basis von Flugversuchsdaten entwickelt. Der Beobachter benötigt dabei lediglich Messgrößen aus dem stehenden Hubschraubersystem, welche auch auf Serienhubschraubern verfügbar sind. Durch die Integration des Beobachters in die Flugregelung soll der Komfort in turbulenter Luft gesteigert werden
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