| 31. |
- Moradian, Farzad, 1981-, et al.
(författare)
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Thermodynamic equilibrium prediction of bed agglomeration tendency in dual fluidized-bed gasification of forest residues
- 2016
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Ingår i: Fuel processing technology. - : Elsevier BV. - 0378-3820 .- 1873-7188. ; 154, s. 82-90
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Tidskriftsartikel (refereegranskat)abstract
- Dual fluidized-bed (DFB) gasification is one of the recently developed technologies for production of heat, power, transportation fuels and synthetic chemicals through steam gasification of biomass. Bed agglomeration is a serious ash-related problem that should be taken into account when biomass-based fuels are selected for fluidized-bed gasification and combustion. This study developed a thermodynamic equilibrium model to assess the risk of bed agglomeration in gasification and combustion reactors of a DFB gasifier using biomass (forest residues) as feedstock. The modelling approach combined thermodynamic equilibrium calculations with chemical fractionation technique to predict the composition and melting behaviour of the fuel-derived ash as well as bed particles coating layer in the gasification and combustion reactors. FactSage was employed for the thermodynamic equilibrium calculations. The modelling results were then compared with experimental data obtained from a full-scale DFB gasifier to estimate the reliability and validity of the predictive model. In general, a good agreement was found between the modelling results and experimental observations. For the forest residues as feedstock and olivine as bed material, the modelling results indicate a low risk of bed agglomeration in the DFB gasifier, as long as the dominant temperature in the combustion zone is below 1020 °C. In contrast, quartz as bed material in the DFB gasifier was shown to significantly increase the risk of bed agglomeration through coating-induced agglomeration mechanism.
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| 32. |
- Benouar, Sara, et al.
(författare)
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Classification of impedance cardiography dZ/dt complex subtypes using pattern recognition artificial neural networks
- 2021
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Ingår i: Biomedizinische Technik (Berlin. Zeitschrift). - : Walter de Gruyter. - 1862-278X .- 0013-5585. ; 66:5, s. 515-527
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Tidskriftsartikel (refereegranskat)abstract
- In impedance cardiography (ICG), the detection of dZ/dt signal (ICG) characteristic points, especially the X point, is a crucial step for the calculation of hemodynamic parameters such as stroke volume (SV) and cardiac output (CO). Unfortunately, for beat-to-beat calculations, the accuracy of the detection is affected by the variability of the ICG complex subtypes. Thus, in this work, automated classification of ICG complexes is proposed to support the detection of ICG characteristic points and the extraction of hemodynamic parameters according to several existing subtypes. A novel pattern recognition artificial neural network (PRANN) approach was implemented, and a divide-and-conquer strategy was used to identify the five different waveforms of the ICG complex waveform with output nodes no greater than 3. The PRANN was trained, tested and validated using a dataset from four volunteers from a measurement of eight electrodes. Once the training was satisfactory, the deployed network was validated on two other datasets that were completely different from the training dataset. As an additional performance validation of the PRANN, each dataset included four volunteers for a total of eight volunteers. The results show an average accuracy of 96% in classifying ICG complex subtypes with only a decrease in the accuracy to 83 and 80% on the validation datasets. This work indicates that the PRANN is a promising method for automated classification of ICG subtypes, facilitating the investigation of the extraction of hemodynamic parameters from beat-to-beat dZ/dt complexes.
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| 33. |
- Benouar, Sara, et al.
(författare)
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Time-series NARX feedback neural network for forecasting impedance cardiography ICG missing points : a predictive model
- 2023
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Ingår i: Frontiers in Physiology. - : Frontiers Media S.A.. - 1664-042X. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- One of the crucial steps in assessing hemodynamic parameters using impedance cardiography (ICG) is the detection of the characteristic points in the dZ/dt ICG complex, especially the X point. The most often estimated parameters from the ICG complex are stroke volume and cardiac output, for which is required the left ventricular pre-ejection time. Unfortunately, for beat-to-beat calculations, the accuracy of detection is affected by the variability of the ICG complex subtypes. Thus, in this work, we aim to create a predictive model that can predict the missing points and decrease the previous work percentages of missing points to support the detection of ICG characteristic points and the extraction of hemodynamic parameters according to several existing subtypes. Thus, a time-series non-linear autoregressive model with exogenous inputs (NARX) feedback neural network approach was implemented to forecast the missing ICG points according to the different existing subtypes. The NARX was trained on two different datasets with an open-loop mode to ensure that the network is fed with correct feedback inputs. Once the training is satisfactory, the loop can be closed for multi-step prediction tests and simulation. The results show that we can predict the missing characteristic points in all the complexes with a success rate ranging between 75% and 88% in the evaluated datasets. Previously, without the NARX predictive model, the successful detection rate was 21%–30% for the same datasets. Thus, this work indicates a promising method and an accuracy increase in the detection of X, Y, O, and Z points for both datasets.
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| 34. |
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| 35. |
- Bray, Lucy, et al.
(författare)
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Developing rights-based standards for children having tests, treatments, examinations and interventions : using a collaborative, multi-phased, multi-method and multi-stakeholder approach to build consensus
- 2023
-
Ingår i: European Journal of Pediatrics. - : Springer Nature. - 0340-6199 .- 1432-1076.
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Tidskriftsartikel (refereegranskat)abstract
- Children continue to experience harm when undergoing clinical procedures despite increased evidence of the need to improve the provision of child-centred care. The international ISupport collaboration aimed to develop standards to outline and explain good procedural practice and the rights of children within the context of a clinical procedure. The rights-based standards for children undergoing tests, treatments, investigations, examinations and interventions were developed using an iterative, multi-phased, multi-method and multi-stakeholder consensus building approach. This consensus approach used a range of online and face to face methods across three phases to ensure ongoing engagement with multiple stakeholders. The views and perspectives of 203 children and young people, 78 parents and 418 multi-disciplinary professionals gathered over a two year period (2020–2022) informed the development of international rights-based standards for the care of children having tests, treatments, examinations and interventions. The standards are the first to reach international multi-stakeholder consensus on definitions of supportive and restraining holds.Conclusion: This is the first study of its kind which outlines international rights-based procedural care standards from multi-stakeholder perspectives. The standards offer health professionals and educators clear evidence-based tools to support discussions and practice changes to challenge prevailing assumptions about holding or restraining children and instead encourage a focus on the interests and rights of the child.What is Known:• Children continue to experience short and long-term harm when undergoing clinical procedures despite increased evidence of the need to improve the provision of child-centred care.• Professionals report uncertainty and tensions in applying evidence-based practice to children’s procedural care. What is New:• This is the first study of its kind which has developed international rights-based procedural care standards from multi-stakeholder perspectives.• The standards are the first to reach international multi-stakeholder consensus on definitions of supportive and restraining holds.
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| 36. |
- Perman, Jeanna, 1981, et al.
(författare)
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The VLDL receptor promotes lipotoxicity and increases mortality in mice following an acute myocardial infarction.
- 2011
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Ingår i: The Journal of clinical investigation. - : American Society for Clinical Investigation. - 1558-8238 .- 0021-9738. ; 121:7, s. 2625-40
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Tidskriftsartikel (refereegranskat)abstract
- Impaired cardiac function is associated with myocardial triglyceride accumulation, but it is not clear how the lipids accumulate or whether this accumulation is detrimental. Here we show that hypoxia/ischemia-induced accumulation of lipids in HL-1 cardiomyocytes and mouse hearts is dependent on expression of the VLDL receptor (VLDLR). Hypoxia-induced VLDLR expression in HL-1 cells was dependent on HIF-1α through its interaction with a hypoxia-responsive element in the Vldlr promoter, and VLDLR promoted the endocytosis of lipoproteins. Furthermore, VLDLR expression was higher in ischemic compared with nonischemic left ventricles from human hearts and was correlated with the total lipid droplet area in the cardiomyocytes. Importantly, Vldlr-/- mice showed improved survival and decreased infarct area following an induced myocardial infarction. ER stress, which leads to apoptosis, is known to be involved in ischemic heart disease. We found that ischemia-induced ER stress and apoptosis in mouse hearts were reduced in Vldlr-/- mice and in mice treated with antibodies specific for VLDLR. These findings suggest that VLDLR-induced lipid accumulation in the ischemic heart worsens survival by increasing ER stress and apoptosis.
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| 37. |
- Wiklund, Urban, et al.
(författare)
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Adaptive spatio-temporal filtering of disturbed ECGs: a multi-channel approach to heartbeat detection in smart clothing
- 2007
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Ingår i: Medical and Biological Engineering and Computing. - : Springer Science and Business Media LLC. - 1741-0444 .- 0140-0118. ; 45:6, s. 515-523
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Tidskriftsartikel (refereegranskat)abstract
- Intermittent disturbances are common in ECG signals recorded with smart clothing: this is mainly because of displacement of the electrodes over the skin. We evaluated a novel adaptive method for spatio-temporal filtering for heartbeat detection in noisy multi-channel ECGs including short signal interruptions in single channels. Using multi-channel database recordings (12-channel ECGs from 10 healthy subjects), the results showed that multi-channel spatio-temporal filtering outperformed regular independent component analysis. We also recorded seven channels of ECG using a T-shirt with textile electrodes. Ten healthy subjects performed different sequences during a 10-min recording: resting, standing, flexing breast muscles, walking and pushups. Using adaptive multi-channel filtering, the sensitivity and precision was above 97% in nine subjects. Adaptive multi-channel spatio-temporal filtering can be used to detect heartbeats in ECGs with high noise levels. One application is heartbeat detection in noisy ECG recordings obtained by integrated textile electrodes in smart clothing.
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| 38. |
- Areljung, Sofie, 1983-, et al.
(författare)
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Potential for multi-dimensional teaching for 'emergent scientific literacy' in pre-school practice
- 2018
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Ingår i: Journal of Emergent Science. - : Association for Science Education. - 2046-4754. ; 15, s. 20-27
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Tidskriftsartikel (refereegranskat)abstract
- How can pre-school teachers form science teaching in a landscape of increasing focus on academically oriented learning outcomes, without losing the unique character of pre-school pedagogies? Seeking to contribute to the discussion of what pre-school science can be, we have analysed data from activities in fourteen Swedish pre-schools (for children aged 1-5 years), to examine if and how multi-dimensional teaching may be combined with teaching for scientific literacy.The overall picture is that elements of ‘emergent scientific literacy' can be combined with a wide range of teaching dimensions, such as empathy, fantasy and storytelling.These results contribute important perspectives to what pre-school science can be and how it can be researched in a way that is suitable for the preschool’s conditions.We suggest our analytical questions, and the dimensions displayed in our results, as a tool for teachers who plan or evaluate science teaching in the early years.
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| 39. |
- Areljung, Sofie, 1983-, et al.
(författare)
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Teaching for Emergent Disciplinary Drawing in Science? Comparing Teachers' and Children's Ways of Representing Science Content in Early Childhood Classrooms
- 2022
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Ingår i: Research in science education. - : Springer. - 0157-244X .- 1573-1898. ; 52:3, s. 909-926
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Tidskriftsartikel (refereegranskat)abstract
- This classroom-based study aims to contribute knowledge about children's opportunities to make use of drawing to make meaning in science. Employing a social semiotic approach to drawing, we examine what ways of representing science content that are (1) made available by the teacher and (2) adopted in children's drawings. We analysed observation data from 11 science lessons in early childhood classrooms (children aged 3 to 8 years), including the drawings that children made during those lessons (129 drawings in total). Our findings suggest that the semiotic resources that teachers provide have a large impact on how children represent science content in their drawings. Moreover, we interpret that teachers strive to support children's 'emergent disciplinary drawing' in science, since they predominantly provided semiotic resources where the science content was generalised and decontextualised. Finally, we propose that 'emergent disciplinary drawing' is incorporated as an element of science pedagogy in ECE practice and ECE teacher education.
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| 40. |
- Areljung, Sofie, 1983-, et al.
(författare)
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The role of children’s drawings in science teaching : A comparison across preschool, preschool class and early primary school
- 2018
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Konferensbidrag (refereegranskat)abstract
- Particularly since many children in early childhood education (ECE) (education for children from birth to 8 years) do not yet write, teachers and researchers tend to use children’s drawings to assess their developing science learning. Previous studies show that children’s choices on what to include in their drawings are affected by local cultures of what constitutes a good representation. However, there is a lack of studies that focus on the teacher perspective, in terms of why and how they include drawing activities in their science teaching. Further, there are currently no studies that compare the role of drawings in science teaching across ECE sectors. The study is part of a larger study which aims to to advance our understanding of how to bridge science teaching across ECE sectors (preschool, preschool class, early primary school). Here, our specific aim is to examine how educational cultures of different ECE sectors interact with teacher’s objectives for using children’s drawings in science activities. We use Activity Theory to analyse field data (notes, photos, videos) from science activities that include children’s drawings, as well as recordings from group discussions with teachers. First, we focus on the relation between the purpose of the activity, the tools used, the local educational culture, and the outcome of each activity. Second, we compare our results across ECE sectors. Our preliminary results indicate that the purpose of drawing activities vary across sectors. In preschool, children’s drawings may serve to tell stories, while in early primary school, drawings may serve as a part of observation practice or to display children’s understandings of science concepts. The results are discussed in relation to children’s transitions between educational cultures, and whether teachers should explicitly scaffold scientific drawing in ECE.
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