Digital Twins of the Ocean (DTO) are a rapidly emerging topic that has attracted significant interest from scientists in recent years. The initiative, strongly driven by the EU, aims to create a digital replica of the ocean to better understand and manage marine environments. The Iliad project, funded under the EU Green Deal call, is developing a framework to support multiple interoperable DTO using a federated systems-of-systems approach across various fields of applications and ocean areas, called pilots. This paper presents the results of a Water Quality DTO pilot located in the Trondheim fjord in Norway. This paper details the building blocks of DTO, specific to this environmental monitoring pilot. A crucial aspect of any DTO is data, which can be sourced internally, externally, or through a hybrid approach utilizing both. To realistically twin ocean processes, the Water Quality pilot acquires data from both surface and benthic observatories, as well as from mobile sensor platforms for on-demand data collection. Data ingested into an InfluxDB are made available to users via an API or an interface for interacting with the DTO and setting up alerts or events to support ’what-if’ scenarios. Grafana, an interactive visualization application, is used to visualize and interact with not only time-series data but also more complex data such as video streams, maps, and embedded applications. An additional visualization approach leverages game technology based on Unity and Cesium, utilizing their advanced rendering capabilities and physical computations to integrate and dynamically render real-time data from the pilot and diverse sources. This paper includes two case studies that illustrate the use of particle sensors to detect microplastics and monitor algae blooms in the fjord. Numerical models for particle fate and transport, OpenDrift and DREAM, are used to forecast the evolution of these events, simulating the distribution of observed plankton and microplastics during the forecasting period.
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Bespreking van onderzoek van Rychard Bouwens in ‘Waar wij trots op zijn. De ontdekkingen van 2011’ van de Universiteit Leiden Faculteit der Wiskunde & Natuurwetenschappen. Het valt goed te begrijpen voor iedereen met een basale kennis van klassieke fotografie: bij weinig licht neem je een lange sluitertijd. En dat is wat Rychard Bouwens deed. Om naar de zogenaamde Dark Ages van het heelal te kijken, hield hij de Hubble-ruimtetelescoop maar liefst 87 uur lang op een plek gericht.
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Bespreking van onderzoek van Anton Akhmerov in ‘Waar wij trots op zijn. De ontdekkingen van 2011’ van de Universiteit Leiden Faculteit der Wiskunde & Natuurwetenschappen. De Leidse theoretisch natuurkundige Anton Akhmerov promoveerde in mei op een onderzoek naar functionele toepassingen van grafeen, een eenlaags koolstofmateriaal dat de afgelopen jaren volop in de belangstelling staat. Daarnaast werkte hij ook nog aan quantumcomputers, omdat hij tijd over had in zijn onderzoek.
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Bespreking van onderzoek van Erik Danen in ‘Waar wij trots op zijn. De ontdekkingen van 2011’ van de Universiteit Leiden Faculteit der Wiskunde & Natuurwetenschappen. Celbioloog Erik Danen doet onderzoek naar de verwoestende – maar in evolutionaire termen ook wonderlijke – strategieën van de kankercel. Met welke trucs verspreiden kankercellen zich door het lichaam? Hoe overleven ze een aanval van een chemokuur? En hoe wrang is het dat de één procent cellen die de therapie overleeft vervolgens dubbelhard terugslaat.
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Bespreking van onderzoek van Todor Stefanov in ‘Waar wij trots op zijn. De ontdekkingen van 2011’ van de Universiteit Leiden Faculteit der Wiskunde & Natuurwetenschappen. De Bulgaar Todor Stefanov onderzoekt methoden en middelen voor het ontwerpen en programmeren van multiprocessorsystemen die zijn geïntegreerd in een enkele chip. Dit om de verwerking van signalen en beelden in bijvoorbeeld smartphones te verbeteren. En dat moet snel, want ieder jaar komt er wel weer een nieuwe generatie op de markt.
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Light scattering is a fundamental property that can be exploited to create essential devices such as particle analysers. The most common particle size analyser relies on measuring the angle-dependent diffracted light from a sample illuminated by a laser beam. Compared to other non-light-based counterparts, such a laser diffraction scheme offers precision, but it does so at the expense of size, complexity and cost. In this paper, we introduce the concept of a new particle size analyser in a collimated beam configuration using a consumer electronic camera and machine learning. The key novelty is a small form factor angular spatial filter that allows for the collection of light scattered by the particles up to predefined discrete angles. The filter is combined with a light-emitting diode and a complementary metal-oxide-semiconductor image sensor array to acquire angularly resolved scattering images. From these images, a machine learning model predicts the volume median diameter of the particles. To validate the proposed device, glass beads with diameters ranging from 13 to 125 µm were measured in suspension at several concentrations. We were able to correct for multiple scattering effects and predict the particle size with mean absolute percentage errors of 5.09% and 2.5% for the cases without and with concentration as an input parameter, respectively. When only spherical particles were analysed, the former error was significantly reduced (0.72%). Given that it is compact (on the order of ten cm) and built with low-cost consumer electronics, the newly designed particle size analyser has significant potential for use outside a standard laboratory, for example, in online and in-line industrial process monitoring.
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Recent and ongoing curriculum innovations in Dutch secondary chemistry education have led to questions about which concepts should be central in the programme and which contexts should be used to embed these concepts into. Another important question is in the discussions about these innovations is: how do students learn chemistry? This thesis examines the relations between students' metacognitive beliefs, their learning outcomes, and the learning activities they conduct in the domain of chemistry. In studying these relations, a useful framework is provided bij Novak's educational theory on 'meaningful learning' as is described in chapter 2. In chapter 3, the development of an instrument for assessing students' metacognitive beliefs regarding chemistry is described. More specifically, this instrument, a questionnaire, consists of items that can be used to determine the nature of students' epistemological beliefs, learning conceptions, and goal orientations concerning chemistry. Using this instrument, it was found that the students' aforementioned metacognitive beliefs were highly interrelated. By means of the data produced in this study, an improved version of the instrument was constructed. We used this version of the instrument in a follow-up study and identified a set of items to assess a student's 'competence mindedness'. 'Competence mindedness' is defined as the extent to which students are oriented towards coming to understand subject matter in the chemical domain. This orientation is for instance inferred from students' beliefs about chemistry as a coherent body of knowledge and about chemistry learning as a process in which knowledge is actively constructed. We describe a student's score on this scale as the extent to which he is oriented towards developing chemical competence, or, in short, the student's 'competence mindedness'. As an indicator of students' chemical competence we used the so-called 'macro-micro concept'. The macro-micro concept consists of the ability to use the macro perspective (focusing on chemical phenomena on a substance level) and micro perspective on chemistry (focusing on the structure and behavior of subatomic particles) interchangeably. Although the macro-micro concept is considered to be a central chemical competence by many experts in the field of chemistry education, the concept itself is not mentioned explicitely in any Dutch chemistry textbook used in secondary education. Using the final version of the instrument described in chapter 3, relations between the competence mindedness of students and a central chemical competency were assessed in chapter 4. Consequently, an explorative study was conducted in which a small number of chemistry teachers was questioned on the extent to which they paid attention to the macro-micro concept in their own teaching. Five out of nine teachers interviewed, held the opinion that the macro-micro concept should be a part of chemistry teaching and consequently dedicated time in class to this concept. The other teachers that were interviewed, did not mention the macro-micro concept as a central chemical concept in the interviews. In another study, students' use of the macro-micro concept when answering regular chemistry test questions, was examined. From this study, it can be concluded that there are large differences in the students' use of this concept. However, from answers given by the students involved, it can be concluded that they use the macro-micro concept. Following from the last two studies mentioned, two more studies were conducted that focused on the use of the macro-micro concept by students. In particular we were interested in the way students use this concept differently than is to be expected from the sequencing of learning contents in chemistry textbooks. More specifically, we conducted two studies to determine if students' competence mindedness and the way they use the macro-micro concept (i.e. starting from the micro aspect or not) are related. In the first, small-scale, study, we concluded that senior students that are more competence minded, more often take the micro aspect of chemistry as a starting point when relating the micro and macro aspects of chemistry. In a follow-up study, a standardized instrument was used to assess students' use of the macro-micro concept. This instrument made it possible to include a larger sample of students in the study. This study confirmed the results found in the small-scale study: more competence minded students were found to prefer relations between the macro and micro aspects of chemistry that started from the micro aspect. Chapter 5 consists of several studies concerning students' notions about how the chemical domain can be described: their chemical domain beliefs. The development of these notions are considered an important indicator of chemical competence. Relations between students' competence mindedness and aspects of their chemical domain beliefs were examined through a repertory test procedure. More specifically, the students involved in this study were asked to compare the subject of chemistry with several other subjects. Thereby, data were gathered on constructs these students' used to describe the subject of chemistry and how they contrasted with the other subjects or resembled them. In another study, relations between students' chemical domain beliefs and the extent to which these students are competence minded were examined. The results show a number of relations between students' competence mindedness and selections of their chemical domain beliefs: in general, more competence minded students more often use concepts like 'chemistry as a science', 'properties of substances', and 'chemical reactions' to typify chemistry. Having found indications that students' competence mindedness regarding chemistry is related to their learning outcomes, the question arises how students' competence mindedness can be enhanced. Moreover, relations between students' competence mindedness and the learning strategies they deploy, have not been taken into consideration up to this point. In chapter 6, a learning environment was redesigned in the form of a student study guide, that is used as a supplement to the chemistry textbook students were used working with. The main purpose of the study guide was to change the type of learning activities students use. The two quasi-experimental studies in which the study guide was used as an intervention, did not lead to significant changes in students' learning activities. However, relations were found between students' learning activities and the extent to which students were competence minded. We conclude therefore, that the learning strategies used by the students involved in the study are in particular a consequence of their metacognitive beliefs, i.e. their competence mindedness, and not of the learning environment concerned.
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From the article: "A facile approach for the fabrication of large-scale interdigitated nanogap electrodes (nanogap IDEs) with a controllable gap was demonstrated with conventional micro-fabrication technology to develop chemocapacitors for gas sensing applications. In this work, interdigitated nanogap electrodes (nanogap IDEs) with gaps from 50–250 nm have been designed and processed at full wafer-scale. These nanogap IDEs were then coated with poly(4-vinyl phenol) as a sensitive layer to form gas sensors for acetone detection at low concentrations. These acetone sensors showed excellent sensing performance with a dynamic range from 1000 ppm to 10 ppm of acetone at room temperature and the observed results are compared with conventional interdigitated microelectrodes according to our previous work. Sensitivity and reproducibility of devices are discussed in detail. Our approach of fabrication of nanogap IDEs together with a simple coating method to apply the sensing layer opens up possibilities to create various nanogap devices in a cost-effective manner for gas sensing applications"
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A local operating theater ventilation device to specifically ventilate the wound area has been developed and investigated. The ventilation device is combined with a blanket which lies over the patient during the operation. Two configurations were studied: Configuration 1 where HEPA-filtered air was supplied around and parallel to the wound area and Configuration 2 where HEPA-filtered air was supplied from the top surface of the blanket, perpendicular to the wound area. A similar approach is investigated in parallel for an instrument table. The objective of the study was to verify the effectiveness of the local device. Prototype solutions developed were studied experimentally (laboratory) and numerically (CFD) in a simplified setup, followed by experimental assessment in a full scale mock-up. Isothermal as well as non-isothermal conditions were analyzed. Particle concentrations obtained in proposed solutions were compared to the concentration without local ventilation. The analysis procedure followed current national guidelines for the assessment of operating theater ventilation systems, which focus on small particles (<10 mm). The results show that the local system can provide better air quality conditions near the wound area compared to a theoretical mixing situation (proof-of-principle). It cannot yet replace the standard unidirectional downflow systems as found for ultraclean operating theater conditions. It does, however, show potential for application in temporary and emergency operating theaters
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The thoracic and peritoneal cavities are lined by serous membranes and are home of the serosal immune system. This immune system fuses innate and adaptive immunity, to maintain local homeostasis and repair local tissue damage, and to cooperate closely with the mucosal immune system. Innate lymphoid cells (ILCs) are found abundantly in the thoracic and peritoneal cavities, and they are crucial in first defense against pathogenic viruses and bacteria. Nanomaterials (NMs) can enter the cavities intentionally for medical purposes, or unintentionally following environmental exposure; subsequent serosal inflammation and cancer (mesothelioma) has gained significant interest. However, reports on adverse effects of NMon ILCs and other components of the serosal immune systemare scarce or even lacking. As ILCs are crucial in the first defense against pathogenic viruses and bacteria, it is possible that serosal exposure to NMmay lead to a reduced resistance against pathogens. Additionally, affected serosal lymphoid tissues and cells may disturb adipose tissue homeostasis. This review aims to provide insight into key effects of NMon the serosal immune system.
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