Placebo effects on cycling performance in virtual-reality and laboratory environments

Placebo effects are a desirable outcome resulting from a person’s expected and/or learned response to a treatment or situation In sport, most research has examined placebo effects by administering a placebo and informing athletes that they received an ergogenic aid, or via manipulating their expectations about an opponent. While previous research has revealed the magnitude of placebo effects during sport performance, it is limited in that they are often conducted in highly controlled environments, and opponents are often a replication of participants’ own performance. Thus, it is unknown if placebo effects are induced outside of the laboratory and whether they can be induced when competing against real opponents. In this research programme, placebo effects induced via both ergogenic aids and opponents were examined when participants completed cycling time trials remotely on a virtual-reality software (i.e., Zwift) or in the laboratory. In Study 1 (N = 44), the reproducibility of 20-min cycling performance on Zwift was confirmed (CV = 3.7%). In Study 2 (N = 67), athletes completed two 20-min cycling time trials on Zwift, before completing a final time trial with the administration of one of four conditions as part of the balanced placebo design [1) told beetroot/given beetroot, 2) told beetroot/given placebo, 3) told placebo/given beetroot, and 4) told placebo/given placebo]). Findings showed no differences in power output (ηp2 = .03) during any condition in comparison to baseline. In Studies 3 and 4, a deceptive intervention was adopted to investigate the effects of different competitive environments on cycling performance, whereby participants were either correctly informed about the nature of the opponent (accurate condition) or informed they received a performance-enhancing substance (deception). In Study 3, after a 20-min baseline time trial, participants (N = 12) competed twice against a virtual avatar replicating their previous baseline performance (competitionBSL) or against a virtual avatar riding at 2% higher power outputs than their best competitive performance (augmented feedback conditions; accurate and deception). Results showed that participants improved performance during competitionBSL (P < .001) and accurate (P = .036) in comparison to baseline but not during deception (P = .152). In Study 4 (n = 14), participants competed against a real opponent of similar ability (± 2% difference achieved during baseline). Contrary to Study 3, performance during both accurate and deception conditions was similar to baseline (all P ≥ 0.134). Collectively, this research has shown that placebo effects might not be as evident in remote-research designs than when conducted in the laboratory, which could be explained by the limited social contact between researchers and participants. These results have important implications for researchers and practitioners interested in placebo effects outside of the controlled environments, highlighting the importance of considering the exercise context. Virtual-reality software an innovative tool in which to conduct experimental designs in applied settings, including a geographically diverse sample, perhaps increasing the generalisability of findings

Digital technologies and privacy: State of the art and research directions

Digital technologies have transformed every aspect of marketing and have brought consumer privacy front and center of research and discourse over the last two decades. Whereas companies and consumers have arguably benefited through the availability and use of data made possible by digitalization, consumer privacy-related concerns raise compelling questions that researchers, companies, and policymakers are addressing. In this Review Paper, we review privacy related to digital technologies in marketing, highlighting the constantly evolving nature of the field. We provide an overview of the rich contributions made by the articles in the special issue on digital technologies and privacy, and the original insights they provide for researchers and practitioners in four domains – communication, retailing, pricing, and product personalization. We identify and outline future research directions in each of these four domains to expand our understanding of privacy at the intersection of psychology and marketing by motivating new scholarly research and providing actionable insights to managers and policymakers

Flow dynamics in a model of a dilated thoracic aorta prior to and following prosthetic replacement

We numerically investigate the flow dynamics in a model of a dilated thoracic aorta, and compare the flow features with the case of a prosthetic replacement in its ascending part. The flow is characterized by an inlet jet which impacts the aortic walls and sweeps toward the aortic arch. Secondary flows generated by the transvalvular jet evolve downstream into a helical flow. The small curvature radius at the end of the aortic arch induces flow separation and vortex shedding in the initial part of the descending aorta, during the systole. The implantation of a prosthesis determines several modifications in the global and local flow patterns. An increase of the pulse wave velocity in the aorta leads to larger pressures inside the vessel, due to the geometrical and rigidity modifications. The sweeping jet is more aligned along the axial direction and propagates faster along the aortic arch. Consequently, a stronger separation of the flow downstream of the aortic arch is observed. By also exploiting manifold analysis, we identify regions characterized by near-wall disordered flows which may present intense accumulation and drop of concentration of biochemicals. These regions are localized downstream of the prosthetic replacement, in the aortic arch, and may be more prone to a new emergence of vessel dilation

Efcacy of sodium bicarbonate ingestion strategies for protecting blinding

Sodium bicarbonate (NaHCO3) is a widely researched ergogenic aid, but the optimal blinding strategy during randomised placebo-controlled trials is unknown. In this multi-study project, we aimed to determine the most efficacious ingestion strategy for blinding NaHCO3 research. During study one, 16 physically active adults tasted 0.3 g·kg-1 body mass NaHCO3 or 0.03 g·kg-1 body mass sodium chloride placebo treatments given in different flavour (orange, blackcurrant) and temperature (chilled, room temperature) solutions. They were required to guess which treatment they had received. During study two, 12 recreational athletes performed time-to-exhaustion (TTE) cycling trials (familiarisation, four experimental). Using a randomised, double-blind design, participants consumed 0.3 g·kg-1 body mass NaHCO3 or a placebo in 5 mL·kg-1 body mass chilled orange squash/water solutions or capsules and indicated what they believed they had received immediately after consumption, pre-TTE and post-TTE. In study one, NaHCO3 prepared in chilled orange squash resulted in the most unsure ratings (44%). In study two, NaHCO3 administered in capsules resulted in more unsure ratings (% here) than NaHCO3 (% here) given in solution, with differences in treatment assignment after consumption, epre-TTE, and post-TTE (all p<0.05). Administering NaHCO3 in capsules was the most efficacious blinding strategy which provides important implications for researchers conducting randomised placebo-controlled trials

Patient Specific Diagnostics for cardiovascular diseases based on diagnostic imaging: an application to the aneurism of the ascending aorta

In the framework of a collaboration between clinicians and engineers (namely, the Department of Radiology of the Brotzu Hospital in Cagliari and the group of experimental hydraulics at DICAAR - University of Cagliari), methodologies for the application of the in vitro study of the cardiovascular fluid mechanics to the support of the physical interpretation of the diagnostic imaging data are being tested. To this aim, we set up a mock-loop able to reproduce the physiologic pulsatile flow and designed to host a replica of aortic root made of transparent silicon rubber. Then, we developed a procedure to obtain a transparent and compliant replica of a patient specific ascending aorta from diagnostic images. The patient specific aorta model can be inserted in the mock-loop to study the fluid dynamics by means of particle image velocimetry techniques. We compared the flow in three cases, corresponding to physiological conditions, mild and severe aortic root dilation, observing significant differences in the redirection of the transvalvular jet and vortex evolution in the aortic flow. The observed fluid dynamics differences may have relevant implications on the thromboembolism and vascular tissue damage potential

Process Mining for Dynamic Modeling of Smart Manufacturing Systems: Data Requirements

Modern manufacturing systems can benefit from the use of digital tools to support both short- and long-term decisions. Meanwhile, such systems reached a high level of complexity and are frequently subject to modifications that can quickly make the digital tools obsolete. In this context, the ability to dynamically generate models of production systems is essential to guarantee their exploitation on the shop-floors as decision-support systems. The literature offers approaches for generating digital models based on real-time data streams. These models can represent a system more precisely at any point in time, as they are continuously updated based on the data. However, most approaches consider only isolated aspects of systems (e.g., reliability models) and focus on a specific modeling purpose (e.g., material flow identification). The research challenge is therefore to develop a novel framework that systematically enables the combination of models extracted through different process mining algorithms. To tackle this challenge, it is critical to define the requirements that enable the emergence of automated modeling and simulation tasks. In this paper, we therefore derive and define data requirements for the models that need to be extracted. We include aspects such as the structure of the manufacturing system and the behavior of its machines. The paper aims at guiding practitioners in designing coherent data structures to enable the coupling of model generation techniques within the digital support system of manufacturing companies

Fluid dynamics and blood damage in the dilated ascending aorta after mechanical prosthetic valve implantation: an in vitro study

The implantation of aortic valve prostheses is often associated with the dilation of the ascending aorta. It is well known that the modification of the fluid dynamics induced by both the prosthetic valve and aortic dilation may, in turn, promote further vessel remodelling. Besides, when the prosthesis is mechanical, a major concern is the blood cell damage and platelet activation which requires a lifelong anticoagulant therapy, which in turn is an additional significant factor of comorbidity. We analysed in vitro the combined effect of the presence of a bileaflet mechanical aortic valve and the dilation of the aortic root in patient specific laboratory models. Three model aortas with increasing degree of dilation, hosted in a mock loop reproducing the heart flow pulsatility, were investigated. The measurement of the time-resolved velocity field allowed the analysis of the general structure of the flow and shear strain-rate distribution. Additionally, the Blood Damage Indexes (BDIs) for both haemolysis and platelet activation were computed along synthetic particle trajectories. Results suggest that a feedback process can be triggered since the aortic dilation tends to decrease the shear stresses at the walls and favour blood stasis: two factors that are known to promote vessel remodelling. Secondly, the analysis of BDIs shows that aortic dilation significantly increases the damage index for haemolysis, whereas a similar effect is not shown when focusing on platelet activation. Graphical abstract: [Figure not available: see fulltext.

Simulation of Chlorine Decay in Water Distribution Networks Using EPANET – Case Study

Deterioration of water quality in distribution networks has a great impact on human health and public acceptance of tap water reaching them. Residual chlorine should be maintained through network pipes to prevent contamination and microbial regrowth. This paper investigates the ability of EPANET 2.0, a free software developed by United States Environment Protection Agency (USEPA), to simulate residual chlorine decay through water networks, taking water-age analyses into consideration, and assesses the feasibility of using it as a measuring and controlling tool to estimate and predict chlorine concentration at different water network points. A study was performed on drinking water network of 6th of October city, where field measurements were done, while data required as program inputs were taken from the daily records of the 6th of October and El-Shaikh Zayed WTPs. The network model was calibrated to minimize error in program results. Errors were evaluated using statistical analyses. The calculated concentrations by the calibrated model were very close to the actual concentrations measured in field at different sampling points for different sampling days. Moreover, EPANET showed that for the water network concerned in this study, chlorine concentrations at network extremities did not recede 0.5 mg/l, the minimum allowable limit established in the Egyptian Code of Practice (ECP), even for those points having water age greater than 24 hours. Keywords: chlorine decay, water quality, water distribution networks, EPANET, water-ag