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The continuing internationalization of business education offers MBA students a unique cross-cultural environment in which to develop their business acumen. This pluralistic context can produce unc...

Gallbladder polyps (also known as polypoid lesions of the gallbladder) are a common incidental finding. The vast majority of gallbladder polyps smaller than 10 mm are not true neoplastic polyps but are benign cholesterol polyps with no inherent risk of malignancy. In addition, recent studies have shown that the overall risk of gallbladder cancer is not increased in patients with small gallbladder polyps, calling into question the rationale for frequent and prolonged follow-up of these common lesions. In 2021, a Society of Radiologists in Ultrasound, or SRU, consensus conference was convened to provide recommendations for the management of incidentally detected gallbladder polyps at US. See also the editorial by Sidhu and Rafailidis in this issue.

How does sentiment in a pitch affect an entrepreneur’s fundraising outcomes? Although research suggests that negativity in entrepreneurial “pitches” to investors adversely impacts resource acquisition, there is a lack of empirical research showing whether, and to what extent, this is true. We study over 30,000 entrepreneurial loan requests from one of the largest loan marketplaces to understand how the sentiment in text-only pitches to investors affects fundraising. In contrast to prior literature, we find that negatively-worded pitches are funded faster than positively-worded ones. We also find that negatively-worded pitches result in lower interest rates to entrepreneurs. Finally, we find that negatively-worded loans default less, suggesting that the benefits of negativity are not one-sided but two-sided: negativity helps both resource seekers and resource providers. Collectively, the results from our study reveal how negativity can be beneficial in impression management and offer fresh insights for the psychological foundations of entrepreneurship.

Wind-Assisted Propulsion Systems (WAPS) can play a key role in achieving the IMO 2050 targets on reducing the total annual GHG emissions from international shipping by at least 50%. The present project deals with the development of a six degree of freedom (DoF) Performance Prediction Program (PPP) for wind-assisted cargo ships aimed at contributing knowledge on WAPS performance. It is a fast and easy tool, able to predict the performance of any commercial ship with three possible different WAPS installed: rotor sails, rigid wing sails and DynaRigs; with only the ship main particulars and general dimensions as input data. The tool is based on semi-empirical methods and a WAPS aerodynamic database created from published data on lift and drag coefficients, which can be interpolated with the aim to scale to different sizes and configurations. A model validation is carried out to evaluate its reliability. The results are compared with the real sailing data of a Long Range 2 (LR2) class wind-assisted tanker vessel, the Maersk Pelican. The study indicates that the PPP shows good agreement with the technology suppliers’ own modelling tool and reasonable agreement with the trends of the real sailing measurements. However, for downwind sailing conditions, the predictions are more conservative than the measured values. Lastly, results showing and comparing power savings for the three different WAPS are presented. Rotor Sails are found to be the most efficient WAPS studied with a much higher potential of driving force generation per square meter of projected sail area.

Introduction INI1-deficient undifferentiated rhabdoid carcinoma is a rare pancreatic carcinoma for which the optimal treatment is unknown. Pancreatic ductal adenocarcinoma, the most common histology of pancreas cancer, is treated with combination chemotherapy in the advanced setting, a strategy supported by strong evidence in well powered studies. In patients with excellent performance status, first-line treatment usually consists of the three-drug regimen FOLFIRINOX, with the combination of gemcitabine with nab-paclitaxel, typically less toxic than the three-drug regimen, reserved for second-line therapy. Given the lack of published reports describing treatment outcomes for patients with rare forms of pancreatic cancer, the same treatment approach used for pancreatic ductal adenocarcinoma is typically employed. Observation This case describes a patient with metastatic pancreatic INI1-deficient undifferentiated rhabdoid carcinoma who was primarily resistant to FOLFIRINOX therapy but who then achieved an immediate, marked and sustained response to gemcitabine with nab-paclitaxel. Conclusion Given the lack of data informing on optimal management of INI1-deficient pancreatic undifferentiated rhabdoid carcinoma, and the exceptional response achieved by gemcitabine with nab-paclitaxel, this case report highlights a surprising and potentially informative anecdote. Additional studies are needed to confirm responses observed in this report which when taken together may strongly influence first-line therapy choice for this rare malignancy. Given the difficult in acquiring sufficient numbers of these rare histologies in any one institution, multi-institution collaboration in studying outcomes of rare pancreatic malignancies is likely essential.

International audience; The paper presents results from the Collaborative Computational Project in Wave Structure Interaction (CCP-WSI) Blind Test Series 2. Without prior access to the physical data, participants, with numerical methods ranging from low-fidelity linear models to fully non-linear Navier–Stokes (NS) solvers, simulate the interaction between focused wave events and two separate, taut-moored, floating structures: a hemispherical-bottomed cylinder and a cylinder with a moonpool. The ‘blind’ numerical predictions for heave, surge, pitch and mooring load, are compared against physical measurements. Dynamic time warping is used to quantify the predictive capability of participating methods. In general, NS solvers and hybrid methods give more accurate predictions; however, heave amplitude is predicted reasonably well by all methods; and a WEC-Sim implementation, with CFD-informed viscous terms, demonstrates comparable predictive capability to even the stronger NS solvers. Large variations in the solutions are observed (even among similar methods), highlighting a need for standardisation in the numerical modelling of WSI problems.

A practical estimation methodology of the mean added resistance in irregular waves is shown, and the present paper provides statistical analyses of estimates for ships in actual conditions. The study merges telemetry data of more than 200 in-service container vessels with ocean re-analysis data from ERA5. Theoretical estimates relying on spectral calculations of added resistance are made for both long- and short-crested waves and are based on a combination of a parametric expression for the wave spectrum and a semi-empirical formula for the added resistance transfer function. The theoretical estimates are compared to predictions from an indirect calculation of added resistance relying on shaft power measurements and empirical estimates of the remaining resistance components. Overall, the comparison reveals a bias in bow oblique waves and higher sea states of the spectral estimates as well as the large variance of the empirically derived predictions — particularly in beam-to-following waves. One of the study’s main findings, confirming previous studies but based on a much larger dataset than in earlier similar studies, is that added resistance assessment based on in-service data is complex due to significant associated uncertainties.

For families facing end-of-life decisions for their critically ill children, compassionate extubation at home is a valuable service that pediatric intensivists can provide. Compassionate extubation at home is resource intensive and can be logistically challenging. Discouragingly, guidance on compassionate extubation at home in the literature is limited. We developed an evidence- and experience-based framework for compassionate extubation at home addressing common planning challenges and resource management. Our objective is to share this framework and an accompanying checklist, so that pediatric intensivists in other institutions can adapt these tools for their use, reducing barriers to providing compassionate extubation at home for critically ill children at the end of life.

We have developed a low-cost approach for accurately measuring short-term vertical motions of the seafloor and maintaining a continuous long-term record of seafloor pressure without the requirement for costly ship time. We equipped the University of Hawai‘i Liquid Robotics Wave Glider with an integrated acoustic telemetry package, a dual-frequency geodetic-grade global positioning system (GPS) receiver, meteorological pressure sensor, processing unit, and cellular communications. The Wave Glider interrogates high accuracy pressure sensors on the seafloor to retrieve their pressure and temperature data. We correct the seafloor pressure measurements using sea surface kinematic GPS location and atmospheric pressure data collected by the Wave Glider payload. By combining the concurrent seafloor and sea surface observations, we demonstrate the capability to provide timely, continuous, and high-accuracy estimation and monitoring of centimeter-scale vertical seafloor motions.

Employees’ receipt of inducements is associated with trust and affective commitment, and employees pay for their inducements with their contributions (e.g., time, and physical and intellectual effo...

Background: Recent European multisociety guidelines recommend routine follow-up imaging of gallbladder polyps (including polyps

This paper is concerned with a machine learning-based approach for sea state estimation using the wave buoy analogy. In-situ sensor data of an advancing medium-size container vessel has been utilized for the prediction of integral sea state parameters. The main novelty of this contribution is the rigorous comparison of time and frequency domain models in terms of accuracy, robustness and computational cost. The frequency domain model is trained on sequences of spectral ordinates derived from cross response spectra, while the time domain model is applied to 5-minute time series of ship responses. Multiple deep neural networks were trained and the sensitivity of individual sensor recordings, sample length, and frequency discretization on estimation accuracy was analysed. An Inception Architecture adapted for sequential data yields the highest out of sample performance in both considered domains. Additionally, multi-task learning was employed, as it is known for increased generalization capability and diminished uncertainty. Overall, it was found that the frequency domain method provides both superior performance and significantly less computational effort for training.

Versions of the non-linear Schrödinger equation are frequently used for modelling the non-linear propagation of water waves. In this paper, we compare two models against the results of fully non-linear numerical simulations. We consider uni-directional versions of the non-linear Schrödinger equation of Dysthe et al. with the hybrid model of Trulsen et al. The model of Trulsen et al. is shown to have clear advantages in all situations considered including modelling wave crest statistics for highly non-linear cases. However, for very broad bandwidths this model does start to break down, presumably due to the inherent limitation of the envelope representation of water waves. This in turn leads to a small, non-physical, leakage of energy in nonlinear simulations, although, this leakage is much smaller than for the version with 5th order linear dispersion relationship.

This article addresses employment arbitration, which is emerging as a controversial method for resolving disputes between employers and employees not represented by a union. Employment arbitration holds great promise as a dispute resolution process for employees who otherwise would never have a hearing on their claims against an employer. However, critics argue that mandatory arbitration is a new corporate tool used to advantage by large companies against consumers, employees, and other “little guys.” In particular, critics caution that in the absence of a union, the process is skewed against the employee, particularly the unrepresented employee. Some have expressed concern that, as institutional repeat players who will use the arbitration process for multiple cases, employers have an advantage over employees, who are unlikely to use it more than once or twice in their lifetimes. The article determines whether there is a measurable repeat player effect, examines possible explanations for its existence, and identifies policy issues for employment arbitration that are raised by the effect.

To identify early sonographic features of gangrenous cholecystitis.101 patients with acute cholecystitis and a pre-operative sonogram were retrospectively reviewed by three radiologists in this IRB-approved and HIPAA-compliant study. Imaging data were correlated with histologic findings and compared using the Fisher's exact test or Student t test with p 0.05 to determine statistical significance.Forty-eight patients had gangrenous cholecystitis and 53 had non-gangrenous acute cholecystitis. Patients with gangrenous cholecystitis tended to be older (67 ± 17 vs 48 ± 18 years; p = 0.0001), male (ratio of male:female 2:1 vs 0.6:1; p = 0.005), tachycardic (60% vs 28%; p = 0.001), and diabetic (25% vs 8%; p = 0.001). Median time between pre-operative sonogram and surgery was 1 day. On imaging, patients with gangrenous cholecystitis were more likely to have echogenic pericholecystic fat (p = 0.001), mucosal discontinuity (p = 0.010), and frank perforation (p = 0.004), while no statistically significant differences were seen in the presence of sloughed mucosa (p = 0.104), pericholecystic fluid (p = 0.523) or wall striations (p = 0.839). In patients with gangrenous cholecystitis and echogenic pericholecystic fat, a smaller subset had concurrent mucosal discontinuity (57%), and a smaller subset of those had concurrent frank perforation (58%). The positive likelihood ratios for gangrenous cholecystitis with echogenic fat and mucosal discontinuity were 4.6 (95% confidence interval 1.9-11.3) and 14.4 (2.0-106), respectively.Echogenic pericholecystic fat and mucosal discontinuity are early sonographic findings that may help identify gangrenous cholecystitis prior to late findings of frank perforation.

Research Summary As firms mature, their founders are often replaced with seasoned executives. When founders are retained, the surrounding top management team (TMT) members are viewed as critical resources in helping compensate for the founder's managerial deficiencies. Surprisingly, however, little is known about how TMT members affect a founder‐led firm's performance later in a firm's life. Using novel methods and a sample of over 2,000 firms, we address this gap. We find that although team structure has a significant impact on the performance of nonfounder‐led firms (consistent with past literature), it has little to no effect on the operating performance of founder‐led firms, suggesting that founder chief executive officers (CEOs) may exert too much control. Thus, the irony is that founders are retained to propel progress but their very retention may prevent progress. Taken together, our findings add to the entrepreneurship, team, and research methods literatures. Managerial Summary Although founders have the entrepreneurial skills to successfully grow a startup, they generally lack the managerial skills required to lead a large, public firm. As a result, many founder CEOs are replaced before a firm goes public. When founders do stay as CEO, the prevailing belief is that they require a strong TMT to help compensate for the founder's managerial deficiencies. However, given founders' desire to retain control, there is a question of whether they will rely on that team, or if they will simply continue to follow their own intuition. We find evidence that founder CEOs are much less likely to listen to and benefit from their teams relative to nonfounder CEOs.

This paper considers pseudo-impulsive numerical solutions to the forward-speed diffraction problem, as derived from classical linearized potential flow theory. Both head- and following-seas cases are treated. Fourth-order finite-difference approximations are applied on overlapping, boundary-fitted grids to obtain solutions using both the Neumann-Kelvin and the double-body flow linearizations of the problem. A method for computing the pseudo-impulsive incident wave forcing in finite water depth using the Fast Fourier Transform (FFT) is presented. The pseudo-impulsive scattering solution is then Fourier transformed into the frequency domain to obtain the wave excitation forces and the body motion response. The calculations are validated against reference solutions for a submerged circular cylinder and a submerged sphere. Calculations are also made for a modern bulk carrier, showing good agreement with experimental measurements.

The relative contributions of free waves and bound waves to the formation of an extreme wave event remains a topic of interest in offshore engineering. A variety of methods have been proposed for identifying and removing the bound wave components. The method of “phase separation” or “phase manipulation” repeats simulations/experiments of a wave field with an offset in the initial phase of the wave components and relies upon summation of the resulting wave fields to isolate the bound harmonics, following from a Stokes expansion in steepness; the method has proven effective in isolating bound harmonics but requires that all cases be repeated. Alternatively, the bound harmonics can be removed using a three-dimensional fast Fourier transform (3D-FFT) of the wave field. However, the Fourier transform requires periodicity in the signal and assumes homogeneity in space and stationarity in time, producing spurious modes otherwise. We compare the phase separation and 3D-FFT approaches for a steep, focusing wave group in deep water using the numerical simulation tool, OceanWave3D, and discuss the effectiveness of both methods.

2020 IEEE International Systems Communications Conference (SYSCON) The Robot Operating System 2 (ROS 2) is an open source middleware used for robotic applications. ROS 2 provides extensive security enhancements and quality of service (QoS) profiles not available in ROS 1. This paper studies the performance of ROS 2 in a small network of nodes, similar to how a group of unmanned assets would operate. Specifically, we analyze ROS 2 under varying QoS and security constraints in a wireless, lossy environment. This is the first work to comprehensively study ROS 2 network performance using QoS and security classification as a function of network scale in an environment that uses Wi-Fi communications. We custom build a simulation architecture that integrates ROS 2 with NS-3, an open source network simulator. Network performance metrics include latency and message drop rate. We show that enabling security results in a higher message drop rate across all QoS profiles. We also show that scaling the network to more nodes results in various consequences with the use of different QoS settings, including an increase in the average latency of messages. We also highlight some of the limitations there were observed with NS-3 and ROS 2. This work was funded and sponsored by the Office of Naval Research via the Consortium for Robotics and Unmanned Systems Education and Research (CRUSER) at NPS.

2020 IEEE International Systems Conference (SysCon) Throughout the Department of Defense, there are ongoing efforts to increase cybersecurity and improve data transfer in unmanned robotic systems (UxS). This paper explores the performance of the Robot Operating System (ROS) 2, which is built with the Data Distribution Service (DDS) standard as a middleware. Based on how quality of service (QoS) parameters are defined in the robotic middleware interface, it is possible to implement strict delivery requirements to different nodes on a dynamic nodal network with multiple unmanned systems con- nected. Through this research, different scenarios with varying QoS settings were implemented and compared to baseline values to help illustrate the impact of latency and throughput on data flow. DDS security settings were also enabled to help understand the cost of overhead and performance when secured data is compared to plaintext baseline values. Our experiments were performed using a basic ROS 2 network consisting of two nodes (one publisher and one subscriber). Our experiments showed a measurable latency and throughput change between different QoS profiles and security settings. We analyze the trends and tradeoffs associated with varying QoS and security settings. This paper provides performance data points that can be used to help future researchers and developers make informative choices when using ROS 2 for UxS. This work was funded and sponsored by the Office of Naval Research via the Consortium for Robotics and Unmanned Systems Education and Research (CRUSER) at NPS.

Using a nested multiple-case study of participating ventures, directors, and mentors of eight of the original U.S. accelerators, we explore how accelerators’ program designs influence new ventures’ ability to access, interpret, and process the external information needed to survive and grow. Through our inductive process, we illuminate the bounded-rationality challenges that may plague all ventures and entrepreneurs—not just those in accelerators—and identify the particular organizational designs that accelerators use to help address these challenges, which left unabated can result in suboptimal performance or even venture failure. Our analysis revealed three key design choices made by accelerators—(1) whether to space out or concentrate consultations with mentors and customers, (2) whether to foster privacy or transparency between peer ventures participating in the same program, and (3) whether to tailor or standardize the program for each venture—and suggests a particular set of choices is associated with improved venture development. Collectively, our findings provide evidence that bounded rationality challenges new ventures differently than it does established firms. We find that entrepreneurs appear to systematically satisfice prematurely across many decisions and thus broadly benefit from increasing the amount of external information searched, often by reigniting search for problems that they already view as solved. Our study also contributes to research on organizational sponsors by revealing practices that help or hinder new venture development and to emerging research on the lean start-up methodology by suggesting that startups benefit from engaging in deep consultative learning prior to experimentation.

Breakwaters are used to provide sheltered areas for loading and unloading of ships, and coastal protection. Often the breakwaters are bottom mounted such as rubble mound breakwaters. However, there can be several advantages to use a Floating Breakwater (FB). Therefore, the objective of this paper is to study the effect of two different damping mechanisms of a floating breakwater. Three basic cross-sections of FBs were tested and analysed in 2D; a regular pontoon (RG), a regular pontoon with wing plates attached (WP), and a regular pontoon with wing plates and porous media attached to the sides (WP P100). The damping of the FB motions was due to wave radiation and viscous damping. The viscous damping originated mainly from vortex generation around the edges of the structure and due to energy loss inside the porous material attached to the vertical sides of the floating breakwater. Attaching wing plates to the floating breakwater significantly reduced the motion, which was also anticipated. When the porous sides were attached the motion of the FB increased compared to the (WP) cross-section, but the wave transmission was reduced. The possibility for incorporating the effect of the damping in the radiation/diffraction code WAMIT was assessed. The study showed that the cross section with wing plates reduced the motions of the breakwater to the largest extend, while the cross section with wing plates and porous media attached to the sides reduced the reflection and transmission most effectively.

Throat packs are commonly inserted by anaesthetists after induction of anaesthesia for dental, maxillofacial, nasal or upper airway surgery. However, the evidence supporting this practice as routine is unclear, especially in the light of accidentally retained throat packs which constitute 'Never Events' as defined by NHS England. On behalf of three relevant national organisations, we therefore conducted a systematic review and literature search to assess the evidence base for benefit, and also the extent and severity of complications associated with throat pack use. Other than descriptions of how to insert throat packs in many standard texts, we could find no study that sought to assess the benefit of their insertion by anaesthetists. Instead, there were many reports of minor and major complications (the latter including serious postoperative airway obstruction and at least one death), and many descriptions of how to avoid complications. As a result of these findings, the three national organisations no longer recommend the routine insertion of throat packs by anaesthetists but advise caution and careful consideration. Two protocols for pack insertion are presented, should their use be judged necessary.

Our purpose is to develop a perspective on how executives form superior strategies in entrepreneurial settings. Understanding how executives achieve such strategies is theoretically intriguing because it pushes beyond the boundary conditions of the traditional strategic logics of position and leverage to the less-understood opportunity logic where advantage is precarious and often short-lived. Understanding how executives form superior strategies in entrepreneurial settings is also practically relevant. Strategically successful firms in these settings like Apple, Facebook, and Dropbox are primary motors for economic growth, but their strategists are challenged by the “high velocity” of their markets and opportunities. Our perspective combines two intertwined themes: (1) broad view of the strategic playing field enabling better visibility and understanding of opportunities (thinking) and (2) action within structures organized at the “edge of chaos” enabling flexible yet efficient capture of opportunities (doing). We describe these themes and opportunity logic and then contrast them with traditional strategic logics like positioning and resource leverage.

Research summary Examining the strategy formation process is central to understanding why some firms in entrepreneurial settings create competitive advantage and succeed while others do not. The strategy formation process, however, remains unclear. While existing work shows the value of learning from experience or having a holistic understanding of how the pieces fit together, there is limited empirical research that fuses the two streams. We first review the extant literature on strategy formation in entrepreneurial settings by organizing around this fundamental tension between strategizing by “doing” versus “thinking.” We then describe recent work that blends the two and conclude with a future research agenda. Managerial summary An effective strategy can be the difference between becoming the next Google or Netflix or floundering as an also-ran. But how should executives in entrepreneurial settings form strategy? Are they better off letting strategy emerge incrementally by learning from experience? Or should they create a holistic understanding of the interdependent activities that constitute strategy with cognitive structures like mental models and analogies? Here, we indicate the extant research findings on strategy formation in entrepreneurial settings for each of these approaches. We also discuss the new research on how they can be effectively combined and outline an agenda for future research to help executives improve their strategy formation process. Copyright © 2017 Strategic Management Society

The response of an offshore wind turbine tower and its monopile foundation has been investigated when exposed to linear and fully nonlinear irregular waves on four different water depths. The investigation focuses on the consequences of including full nonlinearity in the wave kinematics. The linear and nonlinear irregular wave realizations are calculated using the fully nonlinear potential flow wave model OceanWave3D [1]. The linear and nonlinear wave realizations are compared using both a static analysis on a fixed monopile and dynamic calculations with the aeroelastic code Flex5 [2]. The conclusion from this analysis is that linear wave theory is generally sufficient for estimating the fatigue loading, but wave nonlinearity is important in determining the ultimate design loads.

Generally, numerous marine and offshore structures are composed of a number of modules which introduce narrow gaps between the multi-modules arranged side by side. The interaction between water waves and floating structures excites complex wave runup in the gaps and wave forces on the adjacent modules. In this study, free surface oscillations in twin narrow gaps between identical floating rectangular boxes are investigated by establishing a 2D viscous flow numerical wave tank based on a Constrained Interpolation Profile (CIP) method. The Tangent of Hyperbola for INterface Capturing (THINC) method is employed to capture the free surface. The rigid floating bodies are treated by a Virtual Particle Method (VPM). The incident waves are generated by an internal wave maker. For the fixed module cases, the computational results of wave height in narrow gaps are found in good coincidence with the available experimental measurements, especially for the resonant frequencies. The wave forces on the floating bodies are calculated numerically. The characteristic response of wave forces on the leading and rear bodies are consistent with the free surface elevations in the corresponding narrow gaps. With shallow draft, the gap resonance occurs at higher wave number.

Numerical and physical modeling are the two main tools available for predicting the influence of water waves on coastal or offshore structures. Both models have their strengths and weaknesses. An integrated use of numerical and physical modeling which exploits their advantages can provide an optimal description of full-scale, realistic engineering problems. In this series of two papers, we report on a generalized three-dimensional (3D) deterministic coupling theory for multidirectional nonlinear wave propagation from a numerical model to a physical model up to second order. In this work, the second-order coupling theory developed by [Z. Yang, S. Liu, H.B. Bingham and J. Li, 2014a. Second-order coupling of numerical and physical wave tanks for 2D irregular waves. Part I Formulation, implementation and numerical properties. Coast. Eng. 92, 48–60] and the ad hoc unified wave generation theory developed by [H. Zhang, H.A., Schaffer, K.P., Jakobsen, 2007. Deterministic combination of numerical and physical coastal wave models. Coast. Eng. 54, 171–186.] have been extended to include the coupling between multidirectional nonlinear waves. In part I of this article series, the full second-order 3D coupling theory for multidirectional nonlinear waves is been described in detail. A novel generalized fully-nonlinear motion boundary equation has been derived, which allows the interface between the numerical and physical wave domains to be a 3D arbitrarily shaped wavemaker system. The corresponding 3D wave coupling equation is given for I-, L-, and O-shaped wavemaker layouts. The new formulation is presented in a unified form for an arbitrarily shaped layout of planar wavemakers, and covers both hinged and piston wavemaker types. For the second-order dispersive correction of the paddle stroke, the super-harmonic and sub-harmonic wave-wave interactions have been taken into account. For practical implementation, a typical discretization method for the 3D coupling equations is derived by considering the case of the I-shaped piston wavemaker. The new 3D coupling equations are solved by a combined five-point Lagrange interpolation and the fourth-order Runge–Kutta scheme. Numerical evaluations of the implementation have been conducted by considering a theoretical second-order unidirectional wave field over a range of spatial and time resolutions. The results thus obtained indicate that the proposed discretization scheme is accurate and effective. In addition, the precision of the discrete scheme is observed to be closely related to the spatial and temporal resolution. A separate experimental validation of the theory is presented in Part II.

This paper reports on an ongoing international effort to establish guidelines for numerical modeling of wave energy converters, initiated by the International Energy Agency Technology Collaboration Program for Ocean Energy Systems. Initial results for point absorbers were presented in previous work, and here we present results for a breakwater-mounted Oscillating Water Column (OWC) device. The experimental model is at scale 1:4 relative to a full-scale installation in a water depth of 12.8 m. The power-extracting air turbine is modeled by an orifice plate of 1–2% of the internal chamber surface area. Measurements of chamber surface elevation, air flow through the orifice, and pressure difference across the orifice are compared with numerical calculations using both weakly-nonlinear potential flow theory and computational fluid dynamics. Both compressible- and incompressible-flow models are considered, and the effects of air compressibility are found to have a significant influence on the motion of the internal chamber surface. Recommendations are made for reducing uncertainties in future experimental campaigns, which are critical to enable firm conclusions to be drawn about the relative accuracy of the numerical models. It is well-known that boundary element method solutions of the linear potential flow problem (e.g., WAMIT) are singular at infinite frequency when panels are placed directly on the free surface. This is problematic for time-domain solutions where the value of the added mass matrix at infinite frequency is critical, especially for OWC chambers, which are modeled by zero-mass elements on the free surface. A straightforward rational procedure is described to replace ad-hoc solutions to this problem that have been proposed in the literature.

This paper investigates the optimization of second-order control signals required to produce stable non-linear, deep-water waves using a wedge-shaped, plunger-type wave generator. Both numerical and experimental methods are utilized. A fully non-linear and dispersive potential flow (FNPF) solver developed at DTU is used for the numerical work, following improvements that reduce reflection to 1%. The numerical solver is validated against theoretical and experimental data. A defect correction optimization scheme is employed, resulting in optimized control signals for non-dimensional wave numbers of 2.04-8.17 and steepness of 3-7%. These control signals produce waves that are within 2% of stream function theory solutions for the fundamental harmonic component, and within 10% for the second-order harmonic component. The results demonstrate both the applicability of this optimization procedure and the suitability of a heaving wedge for generating stable non-linear deep-water waves.

Wellbore cement is subjected to a number of mechanical, thermal and chemical stress regimes over its lifetime. Therefore, next-generation wellbore cement formulations need to be evaluated in conditions relevant to these environments. In this work, we investigate the mechanism of the alteration of a novel self-healing polymer-cement composite after exposure to a CO2-rich environment by using synchrotron-based X-ray Fluorescence (XRF), X-ray absorption near edge structure (XANES), and scanning electron microscopy coupled with energy dispersive spectroscopy. Results showed that a chemical alteration of the polymer-cement follows the rim carbonation mechanism, similar to conventional cement, although carbonation takes place to a lesser extent in polymer-cements despite the higher porosity. Along with detailed mechanistic insights on carbonation in polymer-cement composite, the performance of these in CO2-rich environment is further studied using standard compressive strength analysis.

Aims Deep learning (DL), a sub-area of artificial intelligence, has demonstrated great promise at automating diagnostic tasks in pathology, yet its translation into clinical settings has been slow. Few studies have examined its impact on pathologist performance, when embedded into clinical workflows. The identification of H. pylori on HE 47 and 126 WSI were respectively used to train and optimize the DL assistant to detect H. pylori, and 130 were used in a clinical experiment in which 3 experienced GI pathologists reviewed the same test set with and without assistance. On the test set, the assistant achieved high performance, with a WSI-level area under the receiver-operating-characteristic curve (AUROC) of 0.965 (95% CI 0.934–0.987). On H. pylori-positive cases, assisted diagnoses were faster ( β ˆ , the fixed effect size for assistance ​= ​−0.557, p ​= ​0.003) and much more accurate (OR ​= ​13.37, p ​ β ˆ for assistance ​= ​0.010, p ​= ​0.860). Conclusions DL can assist pathologists with H. pylori diagnosis, but its integration into clinical workflows requires optimization to mitigate diagnostic uncertainty as a potential consequence of assistance.