We examine how directors with investment banking experience affect firms׳ acquisition behavior. We find that firms with investment bankers on the board have a higher probability of making ...acquisitions. Furthermore, acquirers with investment banker directors experience higher announcement returns, pay lower takeover premiums and advisory fees, and exhibit superior long-run performance. Overall, our results suggest that directors with investment banking experience help firms make better acquisitions, both by identifying suitable targets and by reducing the cost of the deals.
A power take-off oil-hydraulic system is designed for an oscillating wave surge converter. The adaptation of the converter to the power take-off is performed with genetic algorithms in order to find ...out the optimal geometrical and control parameters, while different power take-off layout configurations are simulated to maximize their efficiency. The simulations show that the power take-off of the oscillating wave surge converter is more effective and efficient, because the converter is driven by bigger excitation wave moments, rather than the resonant characteristics of the point absorber converter, and on the other hand, allows a less constrained design optimization of the mechanical interface with the power take-off. It was verified that these key features allow the production of lower oil flowrates at higher pressure levels, lower oil flow speeds at the cylinder ports and lower ratios between hydraulic peak and averaged power, thus characteristics that must be found in an efficient and effective power take-off.
•A power take-off oil-hydraulic system is designed for a bottom-hinged flap type wave energy converter.•The adaptation of the converter to the power take-off is performed with genetic algorithms.•The simulations show that the power take-off of the bottom-hinged plate converter is effective and efficient.•The design allowed production of lower oil flowrates at higher pressure levels, lower oil flow speeds at the cylinder ports.•The design allowed also lower ratios between hydraulic peak and averaged power.
The present study investigated effects of cognitive and visual loads on driving performance after take-over request (TOR) in an automated driving task. Participants completed automated driving in a ...driving simulator without a non-driving related task, with an easy non-driving related task, and with a difficult non-driving related task. The primary task was to monitor the environment and the system state. An N-back task and a Surrogate Reference Task (SuRT) were adapted to induce cognitive and visual loads respectively. The system followed a front vehicle automatically. Driving performance was measured by responses to a critical event (appearance of a broken-down car) after the automated system issued TOR and then terminated. High subjective difficulty of the N-back task was related to increased time and increased steering angle variance in the time course from onset of steering control to lane change, while high subjective difficulty of SuRT was related to increased steering angle variance in the time course after lane change. This suggests that both cognitive and visual loads affect driving performance after TOR in automated driving, but the effects appear in different time courses.
•We tested effects of cognitive and visual loads on driving performance after TOR.•Both cognitive and visual loads affected driving performance after TOR.•However, the effects appeared in different time courses.•The results suggest a need to monitor driver's state in automated driving.
Adipose‐derived mesenchymal stem cell (ADSC)‐based regenerative therapies have shown potential for use in many chronic diseases. Aging diminishes stem cell regenerative potential, yet it is unknown ...whether stem cells from aged donors cause adverse effects in recipients. ADSCs can be obtained using minimally invasive approaches and possess low immunogenicity. Nevertheless, we found that transplanting ADSCs from old donors, but not those from young donors, induces physical dysfunction in older recipient mice. Using single‐cell transcriptomic analysis, we identified a naturally occurring senescent cell‐like population in ADSCs primarily from old donors that resembles in vitro‐generated senescent cells with regard to a number of key pathways. Our study reveals a previously unrecognized health concern due to ADSCs from old donors and lays the foundation for a new avenue of research to devise interventions to reduce harmful effects of ADSCs from old donors.
Take-off behavior is crucial to the overall success of insect migration. Although most high-altitude migratory flights commence with mass take-offs around dusk and dawn, little is known about ...nighttime take-off behavior. The take-off behavior of migratory Sogatella furcifera was investigated in field cages from 2017 to 2019. The species showed a bimodal take-off pattern at dusk and dawn on rainless nights, with mass flight at dusk more intense than dawn flight. However, a higher frequency of take-offs during the nighttime was observed on rainy nights, resulting in the absence of dawn take-offs. Most migratory take-off individuals at dusk and dawn landed on the cage top or the walls above 150 cm, while non-migratory individuals that took off during the nighttime due to rainfall mainly landed on the cage walls below 150 cm. Furthermore, it has been observed that migratory take-off individuals possess stronger sustained flight capabilities and exhibit more immature ovaries compared with non-migratory take-offs. These findings advance our understanding of the take-off behavior of S. furcifera and thus provide a basis for the accurate prediction and management of the migratory dynamics of this pest.
Urban Air Mobility (UAM), a subset of advanced air mobility, is a concept that envisions safe, sustainable, affordable, and accessible air transportation for passenger mobility, cargo delivery, and ...emergency management within or traversing a metropolitan area. In recent years, several companies have designed and tested enabling elements of this concept, including; prototypes of vertical take-off and landing (VTOL) aircraft, operational concepts, and market studies to understand potential business models. While UAM may be enabled by the convergence of several factors, a number of barriers such as weather could present challenges to scaling operations. This research discusses the potential weather and public acceptance challenges for operations in adverse conditions. This article presents a comprehensive seasonal and diurnal climatology analysis using historical observations across anticipated operational altitudes (surface- 5000 ft AGL) at ten metropolitan areas across the United States for the NASA Aeronautics Research Mission Directorate (ARMD). Public perceptions of weather-related societal barriers were evaluated through a five-city general population survey (n = 1,702) where respondents were asked about their views regarding flying in a small aircraft in a variety of adverse weather conditions using a six statement 5-point Likert scale. The results of the climatology analysis found weather most favorable in Los Angeles and San Francisco, with much less favorable conditions in Denver, New York City, and Washington D.C. In the future, equipping automated vehicles, unmanned aircraft systems, and VTOLs with meteorological sensors coupled with machine learning and artificial intelligence could enhance predictive capabilities that reduce flight cancellations and delays for travelers.
The effects of non-Gaussian Lévy noise in a competitive neural model of binocular rivalry are analyzed numerically. We first investigate how Lévy noise added to the input strength changes the period ...of oscillations and leads to the disappearance of the winner-take-all behavior. Noise-induced alternations are then studied in terms of their statistical measures. We are interested in the overlapping of the regions where the model’s behavior satisfies the experimental constraints on the mean dominance duration and the coefficient of variation of the dominance durations. The results indicate that changes in each of the parameters of Lévy noise produce changes in the overlap regions. The differences with Gaussian noise are emphasized. Finally we plot the distributions of the perceptual dominance durations for different parameters of Lévy noise and compare these distributions with gamma, log-normal and Weibull distributions using the Kolmogorov–Smirnov goodness-of-fit test.
•The role of Lévy noise in a neuronal competition model is studied.•Lévy noise can change the period of oscillations for the system.•The evolution of the region matching perceptual dynamics of human observers is discussed.•The histograms of the perceptual dominance times are plotted in the Lévy case.
Converting persistent and renewable wave energy into electricity has been a research focus in recent years. The oscillating-body wave energy converter (WEC) is a promising approach, especially for ...offshore areas. However, conventional oscillating-body WECs with linear power take-off (PTO) systems are less efficient under off-resonance conditions and have a narrow power capture bandwidth, which has inhibited the commercial application of wave energy. In order to enhance the power capture performance, this study examined oscillating-body WECs with three new types of PTO systems: bistable impulsive PTO, coupled linear PTO, and coupled bistable PTO. Governing equations for the heave motion of a WEC were established based on the linear potential theory by coupling the buoy and PTO systems and were numerically calculated with the fourth-order Runge–Kutta method. The influence of PTO parameters such as the spring constant, stable equilibrium position, and mass ratio on the power capture ratio was investigated. The differences among the WECs with different PTOs were analysed to determine the optimum device. Compared with the linear PTO system, the WEC with the bistable impulse PTO system enhanced the power capture ratio for low-frequency regular waves, and WECs with coupled linear or coupled bistable PTO systems increased the power capture ratio for low-frequency regular waves and expanded the power capture spectrum bandwidth when proper PTO parameters were applied.
•Three new power take-off (PTO) systems for a wave energy converter (WEC).•Influence of PTO parameters on the power capture ratio was studied.•WEC with bistable PTO can enhance power capture ratio at low-frequency waves.•WECs with coupled (linear or bistable) PTOs expand power capture spectrum bandwidth.
Constrained optimization problems arise in numerous scientific and engineering applications, and many papers on the online solution of constrained optimization problems using projection neural ...networks have been published in the literature. The purpose of this paper is to provide a comprehensive review of the research on projection neural networks for solving various constrained optimizations as well as their applications. Since convergence and stability are important for projection neural networks, theoretical results of projection neural networks are reviewed in detail. In addition, various applications of projection neural networks, e.g., the motion generation of redundant robot manipulators, coordination control of multiple robots with limited communications, generation of winner-take-all strategy, model predictive control and WSN localizations, are discussed and compared. Concluding remarks and future directions of projection neural networks as well as their applications are provided.
•The work constructs a bridge between mathematical optimization and neural networks.•A comprehensive review of the research on projection neural networks is presented.•Various applications of projection neural networks are discussed and compared.
Summary
Aging is a multifactorial process where deterioration of body functions is driven by stochastic damage while counteracted by distinct genetically encoded repair systems. To better understand ...the genetic component of aging, many studies have addressed the gene and protein expression profiles of various aging model systems engaging different organisms from yeast to human. The recently identified small non‐coding miRNAs are potent post‐transcriptional regulators that can modify the expression of up to several hundred target genes per single miRNA, similar to transcription factors. Increasing evidence shows that miRNAs contribute to the regulation of most if not all important physiological processes, including aging. However, so far the contribution of miRNAs to age‐related and senescence‐related changes in gene expression remains elusive. To address this question, we have selected four replicative cell aging models including endothelial cells, replicated CD8+ T cells, renal proximal tubular epithelial cells, and skin fibroblasts. Further included were three organismal aging models including foreskin, mesenchymal stem cells, and CD8+ T cell populations from old and young donors. Using locked nucleic acid‐based miRNA microarrays, we identified four commonly regulated miRNAs, miR‐17 down‐regulated in all seven; miR‐19b and miR‐20a, down‐regulated in six models; and miR‐106a down‐regulated in five models. Decrease in these miRNAs correlated with increased transcript levels of some established target genes, especially the cdk inhibitor p21/CDKN1A. These results establish miRNAs as novel markers of cell aging in humans.
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