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Symptoms of adjustment disorder during the COVID-19 pandemic:A longitudinal study
Get PDFAchtergrond: In deze longitudinale studie onderzochten we in welke mate symptomen van een aanpassingsstoornis (AS) in de Nederlandse bevolking in reactie op de COVID-19-pandemie voorkwamen.Doel: Nagaan welke persoonskenmerken (a) en welke pandemiegerelateerde (b), gezondheidgerelateerde (c) of traumagerelateerde factoren (d) een rol speelden bij de ernst van deze symptomen en de verandering in tijd.Methode: Een onlinevragenlijst werd ingevuld door 2079 mensen (meetmoment 1) en 777 mensen (meetmoment 2). De prevalentie van de aanpassingsstoornis werd bepaald en de samenhang over tijd werd onderzocht met vier clusters van factoren (a-d).Resultaten: Een derde ervoer hevige aanpassingsproblemen aan het begin van de pandemie; een half jaar later bleek dat gemiddeld gelijkgebleven. Er waren echter wijzigingen in het beloop van de aanpassing: een vrij grote groep mensen voldeed op meetmoment 1 niet aan de criteria van een AS, terwijl zij dat op meetmoment 2 wel deden, en vice versa. De betrokken factoren (a-d) droegen weliswaar bij aan een verklaring van de variatie in aanpassingsreacties tussen deelnemers (respectievelijk 27% op meetmoment 1 en 44% op meetmoment 2), maar deden dat niet volledig.Conclusie: Een meer individualistische kijk om voorspellers van transities in klachtenpatronen over tijd te bestuderen is nodig. Terwijl een minderheid symptomen van een AS kreeg, bleek de meerderheid goed in staat met de impact van de pandemie om te gaan
Motion of bulk nanobubbles driven by thermal Marangoni flow
Get PDFThermal Marangoni effects play important roles in bubble dynamics such as bubbles generated by water electrolysis or boiling. As macroscopic bubbles often originate from nucleated nanobubbles, it is crucial to understand how thermocapillarity operates at the nanoscale. In this study, the motion of transient bulk gas nanobubbles in water driven by a vertical temperature gradient between two solid plates is investigated using molecular dynamics simulations and analytical theory. The simulation results show that due to the thermal Marangoni force, nanobubbles move towards the hot plate at a constant velocity, similar to the behaviour of macroscale gas bubbles. However, unlike macroscale gas bubbles whose thermal conductivity and viscosity are negligible compared to those of water, the thermal conductivity and viscosity of nanoscale gas bubbles are significantly increased due to their large gas density. The thermal resistance and the slip length are also found to matter at the liquid-gas interface, though they decrease with increasing gas densities. The previous thermocapillary theory for macroscale bubbles is extended by considering all these nanoscopic effects. Expressions of the Marangoni force and the drag force are derived. By balancing the Marangoni force and the drag force, the theoretical velocity of the nanobubble migration in a thermal gradient is obtained. When using the measured transport properties of liquid, gas, and their interfaces, the theoretically obtained velocity is consistent with the result of the molecular simulations. We find that the slip length is too small to have considerable effects on nanobubble motions in the current liquid-gas system.</p
Combined effects of electrode morphology and electrolyte composition on single H<sub>2</sub> gas bubble detachment during hydrogen evolution reaction
Get PDFDuring the hydrogen evolution reaction, H2 gas bubbles form on the electrode surface, significantly affecting electrochemical processes, particularly at high current densities. While promoting bubble detachment has been shown to enhance the current density, the mechanisms governing gas bubble detachment at the electrochemical interface remain poorly understood. In this study, we investigated the interplay between electrode surface morphology and electrolyte composition on single H2 gas bubble detachment during hydrogen evolution reaction (HER). Using well-defined Pt microelectrodes as model systems, we systematically modify and enhance their surface roughness through mechanical polishing to investigate these effects in detail. By modulating the Marangoni effect through variations in electrolyte composition and applied potential, we identified two distinct detachment behaviours. When the Marangoni force acts towards the electrodes, H2 gas bubbles are positioned closer to the electrode surface and exhibit roughness-dependent detachment, with smaller bubbles detaching earlier on rougher surfaces. Conversely, when the Marangoni force is directed away from the electrode, H2 gas bubbles are located farther from the electrode surface and show roughness-independent detachment sizes. These findings highlight the importance of considering both electrode and electrolyte effects to optimize gas bubble detachment during electrochemical reactions.</p
Maintaining human-AI trust:Understanding breakdowns and repair
Get PDFPeople are increasingly working with Artificial Intelligence (AI) agents, whether as softwarebased systems such as AI-chatbots and voice assistants, or embedded in hardware devices like autonomous vehicles, advanced robots, and drones. The idea of Human-AI (H-AI) collaboration is promising, since humans and AI possess complementary skills that, when combined, can enhance performance beyond the capabilities of its individual members. Here, the real challenge is not just determining which tasks are better suited for humans or machines working independently, but in finding ways to enhance their respective strengths through effective interaction. Working together towards a common goal requires good cooperation, coordination, and communication, and it is within these areas that the true challenges lie.A key component in these activities is trust, as it allows individuals to depend on each other’s contributions to complete tasks and achieve shared goals. More specifically, maintaining balanced trust (i.e., neither too much nor too little) is crucial for safe and effective H-AI collaborations. Finding this balance, a process known as trust calibration, should enable people to determine when to rely on AI agents and when to override them. To facilitate this, we need to understand how H-AI trust is built, breaks down, and recovers (i.e., the ‘trust lifecycle’). This dissertation focusses on how to maintain H-AI trust, by examining how trust breaks down (i.e., trust violations) and the mechanisms through which trust can be repaired
Endovascular treatment in comatose patients with anterior circulation ischemic stroke
Get PDFBackground: Coma in the first hours after anterior circulation ischemic stroke is rare. We aimed to assess the causes of coma and outcomes after endovascular thrombectomy (EVT) in this relatively unexplored subgroup of patients. Materials and methods: We used data from the MR CLEAN Registry, a prospective, multicenter, observational cohort study of patients treated with EVT in the Netherlands between March 2014, and December 2018. We included patients with anterior circulation ischemic stroke treated within 6.5 h of symptom onset and assessed frequency and causes of coma, defined as a score of 8 or lower on the Glasgow Coma Scale. Patients with a posterior circulation stroke were excluded. The primary outcome was the score on the modified Rankin Scale at 90 days. We compared outcomes of comatose and non-comatose patients with logistic regression. Results: Fifty-two (1%) of 4,869 patients were comatose. The main causes of coma were bilateral ischemia, a post-ictal state after an epileptic seizure, and respiratory insufficiency. Comatose patients were less likely to receive intravenous thrombolysis (54% vs. 73%; p = 0.004) and onset-to-groin times were longer (226 vs. 199 min; p = 0.012). Patients with coma had poorer functional outcomes (adjusted common odds ratio (OR), 2.73; 95%CI: 1.45–5.13) and more frequently died within 90 days (adjusted OR, 2.95; 95%CI: 1.47–5.90). Conclusion: Bilateral ischemia, a post-ictal state after an epileptic seizure and respiratory insufficiency are common causes of coma in patients with anterior circulation ischemic stroke treated with EVT. These patients have a high risk of death or dependency at 90 days.</p
Additive Manufacturing of Soft Robots based on Graded Porous Structures
No full textSoft robotics is a relatively new approach to designing robots that incorporate soft and smart materials. This approach was inspired by the (soft) octopus tentacle and (soft) elephant trunk, which can perform complex tasks and seamlessly incorporate actuation, sensing, control, and more in a single structure. Researchers have been exploring unconventional materials such as rubber, textile, and foam for these integrated structures. This dissertation explored the Additive Manufacturing (AM) of porous/foam-like structures to integrate sensing and actuation for soft robots and sensors. These foam-like structures have the advantage of being lightweight, allowing for fluid transport, and stiffness regulation. These features make porous structures a promising platform for soft robotics, while AM provides (among other) multi-material capabilities and geometric freedom.To have a soft base material, we developed our own dual pellet extruder to print thermoplastic elastomers (TPEs). This pellet extruder could 3D print soft airtight membranes (0.2-1.2 mm) from TPEs down to Shore Hardness 00-30, which could be inflated up to a stretch of 1320%, and utilized for a bending actuator and a membrane-based sucker and gripper.We then developed the InFoam method to directly fabricate porous structures using TPEs. This method used the liquid rope coiling effect, which is the coiling seen when dropping a viscous liquid such as honey from a height, to create user-defined porosity gradients. Specifically, we established an empirical relationship between the process parameters (nozzle height and extrusion speed) and the resulting coiling pattern. We observed that the porosity magnitude could program the mechanical and actuation properties, which included changing the modulus by more than two orders of magnitude. We combined this large modulus change with normal 3D printing to create bending, contracting, and twisting actuators.Next, we used an electrically conductive TPE to add piezoresistive sensing to the foam-like/porous structures. These 3D printed piezoresistive sensing foam-like structures were used for multiple applications: a sensorized insole for measuring ground reaction forces, a wide range soft tactile sensor by using a layered porosity gradient, and sensorized actuators (incl. a 3DoF bending segment). The resistance changes of these sensors exhibited nonlinearities and hysteresis, which made estimating the stress/force or strain challenging. To compensate for these nonlinearities, we explored the system identification of Hammerstein-Wiener models, which gave good results (on average RMSE <7%). In addition, through characterization, we observed that the porosity had a power-law relationship with multiple mechanical, actuation, and sensing properties.Overall, this thesis contributes to AM of soft robotics based on foam-like/porous structures by (i) the design/usage of pellet extruders, (ii) exploring nonlinear system identification for foam-like structures, (iii), developing the InFoam method, and (iv) investigating the empirical relation between porosity and sensing/actuation behavior.<br/
The algebraic numerical range as a spectral set in Banach algebras
Get PDFWe investigate when the algebraic numerical range is a C-spectral set in a Banach algebra. While providing several counterexamples based on classical ideas as well as combinatorial Banach spaces, we discuss positive results for matrix algebras and provide an absolute constant in the case of complex 2 × 2-matrices with the induced 1-norm. Furthermore, we discuss positive results for infinite-dimensional Banach algebras, including the Calkin algebra.</p
Condemned to Authenticity:Corporate Branding through an Existentialist Lens
No full textCorporate branding has long been shaped by the assumption of a fixed, essential pathway towards an ‘authentic moral identity,’ reinforcing essentialist thought. However, as corporate brands increasingly navigate complex landscapes, essentialism reduces morality and authenticity to a set of criteria, overlooking its subjective and emergent nature. This conceptual paper critiques essentialist thought in corporate branding, arguing that conscientious corporate brands engage in a process of becoming worthy of moral consideration, which resonates with existentialist philosophy. Existentialism shelves predetermined essences and confronts human existence by emphasizing the primacy of authentic constructed meaning, (inter)subjective experience, freedom, and responsibility. What could existentialism mean for authentic corporate brands? And how can corporate brands pursue their true authentic self? By framing corporate brands as ‘condemned to authenticity’—in a state of perpetual becoming—we propose an existentialist rethinking of authenticity. This lens reshapes corporate branding towards nested, emergent phenomena, offering tenets grounded in existentialist thought, and addressing both theoretical and practical implications for brand orchestration
6.3 Barriers and opportunities to AE system development:insights from WaterWarmth pilots
Get PDFThe main research question that guides the analysis for this Work Package 6 Deliverable 6.3 report is: What are the barriers and opportunities that govern niche development and scaling of aqua thermal energy (AE) systems? In answering this research question, we map and analyze the enabling policy and opportunities that support AE system niche development, as well as policy that can also play a role in up-scaling and outscaling of AE systems and practices through demonstration pilots. The report also identifies barriers that (could potentially) hinder AE system niche development. The focus of the report is on the AE pilots of the Interreg North Sea WaterWarmth Project and is therefore primarily based on interviews and pilot text documents. We compiled a set of key questions that were designed to explore issues related to governance and implementation of renewable energy systems. For this report we particularly explored issues about the tensions and challenges faced by the pilots as well as enabling factors that lead to successes in the implementation and scaling of their projects. We studied nine pilot projects using an exploratory multi-case study approach. The first questions for mapping the AE projects were asked to the pilots in an on-line online survey April 2024. A workshop was then held in Caen May 2024 and in the next step semi-structured interviews were carried out with key respondents involved in the nine pilots during the Fall of 2024. The results are first analyzed case-by-case, and then a multi-case synthesis is presented followed by conclusions and policy recommendations.Results show that all the nine pilot projects have experienced several barriers that hinder AE niche development but also referred to important enablers. Policy and regulation barriers were observed in all cases. Lack of clear policy and regulations included complex regulations and inconsistent policies for AE systems. Working closely with policy and governance stakeholders was regarded as an enabling factor in developing the projects, especially at the early phases. Having no internal vision was considered a barrier as it leads to difficulty in formulating a business plan that in turn may hinder securing funding. Lack of financial support is in turn one of the key barriers for the projects having challenges in securing bank guarantees for equipment and operation costs as well as permitting costs. The novelty of the technology in some countries also created barriers in convincing permitting authorities and finance stakeholders about project viability. Further, lack of expertise was seen as something that could be overcome through sharing experiences with similar projects in the same regions or in other countries. Exchange of lessons lead to strengthening of the project and peer-to-peer feedback. Support of fossil fuels by governments reduces subsidies for innovations such as AE systems and leads to lack of incentives for adapting AE or large-scale collective energy systems and is therefore regarded as unfair competition for renewable energy alternatives. Reluctance and lack of acceptance of AE technology due to skepticism about renewable energy technologies is also a hindrance to AE development. Finally, lack of public awareness is a related barrier which can partly be attributed to keystakeholders withholding information that could benefit the projects through information exchange. Regarding enablers, networks and stakeholder collaboration were regarded as fundamental in the implementation andsuccess of projects. Good communication with these stakeholders was also seen as a key success and an enabling factor to ensure a full understanding of the project details and expectations. Through this analysis of barriers and enablers a solid basis is created for mapping and developing insights into how to resolve such hurdles, which is also a key component of the coming WP6 report D6.4., which will present a key vision, strategy and transition policy pathways. This may include developing and implementing specific policy instruments or policy mixes, or by using networking and participatory arrangements