Objective: There are widespread shortages of personal protective equipment as a result of the COVID-19 pandemic. Reprocessing filtering facepiece particle (FFP)-type respirators may provide an alternative solution in keeping healthcare professionals safe. Design: Prospective, bench-to-bedside. Setting: A primary care-based study using FFP-2 respirators without exhalation valve (3M Aura 1862+ (20 samples), Maco Pharma ZZM002 (14 samples)), FFP-2 respirators with valve (3M Aura 9322+ (six samples) and San Huei 2920V (16 samples)) and valved FFP type 3 respirators (Safe Worker 1016 (10 samples)). Interventions: All masks were reprocessed using a medical autoclave (17 min at 121°C with 34 min total cycle time) and subsequently tested up to three times whether these respirators retained their integrity (seal check and pressure drop) and ability to filter small particles (0.3–5.0 µm) in the laboratory using a particle penetration test. Results: We tested 33 respirators and 66 samples for filter capacity. All FFP-2 respirators retained their shape, whereas half of the decontaminated FFP-3 respirators showed deformities and failed the seal check. The filtering capacity of the 3M Aura 1862 was best retained after one, two and three decontamination cycles (0.3 µm: 99.3%±0.3% (new) vs 97.0±1.3, 94.2±1.3% or 94.4±1.6; p<0.001). Of the other FFP-2 respirators, the San Huei 2920 V had 95.5%±0.7% at baseline vs 92.3%±1.7% vs 90.0±0.7 after one-time and two-time decontaminations, respectively (p<0.001). The tested FFP-3 respirator (Safe Worker 1016) had a filter capacity of 96.5%±0.7% at baseline and 60.3%±5.7% after one-time decontamination (p<0.001). Breathing and pressure resistance tests indicated no relevant pressure changes between respirators that were used once, twice or thrice. Conclusion: This small single-centre study shows that selected FFP-2 respirators may be reprocessed for use in primary care, as the tested masks retain their shape, ability to retain particles and breathing comfort after decontamination using a medical autoclave.
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In recent years, there has been an exponential increase in the use of health and sports-related smartphone applications (apps). This is also reflected in App-stores, which are stacked with thousands of health- and sports-apps, with new apps launched each day. These apps have great potential to monitor and support people’s physical activity and health. For users, however, it is difficult to know which app suits their needs. In this paper, we present an online tool that supports the decision-making process for choosing an appropriate app. We constructed and validated a screening instrument to assess app content quality, together with the assessment of users’ needs. Both served as input for building the tool through various iterations with prototypes and user tests. This resulted in an online tool which relies on app content quality scores to match the users’ needs with apps that score high in the screening instrument on those particular needs. Users can add new apps to the database via the screening instrument, making the tool self-supportive and future proof. A feedback loop allows users to give feedback on the recommended app and how well it meets their needs. This feedback is added to the database and used in future filtering and recommendations. The principles used can be applied to other areas of sports, physical activity and health to help users to select an app that suits their needs. Potentially increasing the long-term use of apps to monitor and to support physical activity and health.
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Citizens regularly search the Web to make informed decisions on daily life questions, like online purchases, but how they reason with the results is unknown. This reasoning involves engaging with data in ways that require statistical literacy, which is crucial for navigating contemporary data. However, many adults struggle to critically evaluate and interpret such data and make data-informed decisions. Existing literature provides limited insight into how citizens engage with web-sourced information. We investigated: How do adults reason statistically with web-search results to answer daily life questions? In this case study, we observed and interviewed three vocationally educated adults searching for products or mortgages. Unlike data producers, consumers handle pre-existing, often ambiguous data with unclear populations and no single dataset. Participants encountered unstructured (web links) and structured data (prices). We analysed their reasoning and the process of preparing data, which is part of data-ing. Key data-ing actions included judging relevance and trustworthiness of the data and using proxy variables when relevant data were missing (e.g., price for product quality). Participants’ statistical reasoning was mainly informal. For example, they reasoned about association but did not calculate a measure of it, nor assess underlying distributions. This study theoretically contributes to understanding data-ing and why contemporary data may necessitate updating the investigative cycle. As current education focuses mainly on producers’ tasks, we advocate including consumers’ tasks by using authentic contexts (e.g., music, environment, deferred payment) to promote data exploration, informal statistical reasoning, and critical web-search skills—including selecting and filtering information, identifying bias, and evaluating sources.
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In de gemeente Oostzaan is een opvangbekken voor regenwater gerealiseerd waarbij het regenwater vertraagd, via een ‘zuiverende dijk’, in het oppervlaktewater terecht komt. De dijk maakt deel uit van een innovatief watersysteem, dat is aangelegd op het nieuwe bedrijvenpark De Bombraak in de gemeente Oostzaan. Speciale steensoorten in de dijk en het wateropvangbekken zuiveren het regenwater, zodat de kwaliteit van het oppervlaktewater op peil blijft.
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Social networks and news outlets entrust content curation to specialised algorithms from the broad family of recommender systems. Companies attempt to increase engagement by connecting users with ideas they are more likely to agree with. Eli Pariser, the author of the term filter bubble, suggested that it might come as a price of narrowing users' outlook. Although empirical studies on algorithmic recommendation showed no reduction in diversity, these algorithms are still a source of concern due to the increased societal polarisation of opinions. Diversity has been widely discussed in the literature, but little attention has been paid to the dynamics of user opinions when influenced by algorithmic curation and social network interaction.This paper describes our empirical research using an Agent-based modelling (ABM) approach to simulate users' emergent behaviour and track their opinions when getting news from news outlets and social networks. We address under which circumstances algorithmic filtering and social network dynamics affect users' innate opinions and which interventions can mitigate the effect.The simulation confirmed that an environment curated by a recommender system did not reduce diversity. The same outcome was observed in a simple social network with items shared among users. However, opinions were less susceptible to change: The difference between users' current and innate opinions was lower than in an environment with users randomly selecting items. Finally, we propose a modification to the collaborative filtering algorithm by selecting items in the boundary of users' latitude of acceptance, increasing the chances to challenge users' opinions.
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Dit artikel gaat over de waarde van Twitter als een nieuwsbron voor journalisten. Het artikel poogt de theoretische discussie in de literatuur over de mogelijkheden en de waarde van Twitter een empirische grondslag te geven. In die discussie speelt het artikel van Alfred Hermida, 'Twittering the News', een centrale rol. In dit artikel wordt berichtgeving via Twitter rondom de crash van Turkish Airline TK 1951 op 25 februari 2009 op Schiphol tot uitgangspunt genomen. De analyse, gebaseerd op een beoordeling van de tweets op verschillende variabelen, beschrijft de nieuwswaarde van Twitter en laat zien hoe het nieuws via Twitter zich ontwikkelt. Ten tweede wordt een vergelijking gemaakt met de crash van Ryanair in Schotland op 23 december en de crash van American Airlines op 22 december op het vliegveld van Kingston op Jamaica. Deze drie gevallen zijn als ongeval goed vergelijkbaar en op alle drie de gevallen is eenzelfde analyse toegepast, waarbij duidelijk verschillen zijn aan te wijzen in de rol van Twitter als nieuwsbron. Aan het eind van het artikel komt de vraag aan de orde of 'wisdom of the crowds', dat is het filteren van het nieuws door de gebruikers zelf, een rol speelt? Daarvoor wordt een vergelijking gemaakt tussen de tweets rondom de Schiphol crash en de verslaggeving via Coveritlive, waarin ook gebruik werd gemaakt van de input van Twitter en commentaar van de gebruikers, en waarbij een journalist de rol van moderator had.
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Algorithmic curation is a helpful solution for the massive amount of content on the web. The term is used to describe how platforms automate the recommendation of content to users. News outlets, social networks and search engines widely use recommendation systems. Such automation has led to worries about selective exposure and its side effects. Echo chambers occur when we are over-exposed to the news we like or agree with, distorting our perception of reality (1). Filter bubbles arise where the information we dislike or disagree with is automatically filtered out – narrowing what we know (2). While the idea of Filter Bubbles makes logical sense, the magnitude of the "filter bubble effect", reducing diversity, has been questioned [3]. Most empirical studies indicate that algorithmic recommendations have not locked large audience segments into bubbles [4]. However, little attention has been paid to the interplay between technological, social, and cognitive filters. We proposed an Agent-based Modelling to simulate users' emergent behaviour and track their opinions when getting news from news outlets and social networks. The model aims to understand under which circumstances algorithmic filtering and social network dynamics affect users' innate opinions and which interventions can mitigate the effect. Agent-based models simulate the behaviour of multiple individual agents forming a larger society. The behaviour of the individual agents can be elementary, yet the population's behaviour can be much more than the sum of its parts. We have designed different scenarios to analyse the contributing factors to the emergence of filter bubbles. It includes different recommendation algorithms and social network dynamics. Cognitive filters are based on the Triple Filter Bubble model [5].References1.Richard Fletcher, 20202.Eli Pariser, 20123.Chitra & Musco, 20204. Möller et al., 20185. Daniel Geschke et al, 2018
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This paper describes the concept of a new algorithm to control an Unmanned Aerial System (UAS) for accurate autonomous indoor flight. Inside a greenhouse, Global Positioning System (GPS) signals are not reliable and not accurate enough. As an alternative, Ultra Wide Band (UWB) is used for localization. The noise is compensated by combining the UWB with the delta position signal from a novel optical flow algorithm through a Kalman Filter (KF). The end result is an accurate and stable position signal with low noise and low drift.
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The Smart Current Limiter is a switching DC to DC converter that provides a digitally pre-set input current control for inrush limiting and power management. Being able to digitally adjust the current level in combination with external feedback can be used for control systems like temperature control in high power DC appliances. Traditionally inrush current limiting is done using a passive resistance whose resistance changes depending on the current level. Bypassing this inrush limiting resister with a Mosfet improves efficiency and controllability, but footprint and losses remain large. A switched current mode controlled inrush limiter can limit inrush currents and even control the amount of current passing to the application. This enables power management and inrush current limitation in a single device. To reduce footprint and costs a balance between losses and cost-price on one side and electromagnetic interference on the other side is sought and an optimum switching frequency is chosen. To reduce cost and copper usage, switching happens on a high frequency of 300kHz. This increases the switching losses but greatly reduces the inductor size and cost compared to switching supplies running on lower frequencies. Additional filter circuits like snubbers are necessary to keep the control signals and therefore the output current stable.
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The problem of single-use personal protective equipment (PPE) made from non-renewable resources polluting the environment encouraged the creation of a circular face mask. The main factors that influence the design of a face mask that protects the user from COVID-19 were investigated. According to the findings, these are filtration, fit performance, and comfortability. Therefore, the two following goals were set for this project, to design a face mask (1) produced in the Netherlands using 50% local circular materials and 50% recyclable materials and (2) that perfectly fits men's and women’s faces
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