| 1. |
- Chen, Shih-Ying, et al.
(författare)
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Transport of Contaminated Agents in Hospital Wards - Exposure Control with a Personalized Healthcare Ventilation System: Numerical Study
- 2021
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Konferensbidrag (refereegranskat)abstract
- Contaminated agents in hospital wards are the source of nosocomial infections known as hospital-acquired infection (HAI) or healthcare-associated infections (HAIs). Ventilation plays an essential role in the spreading and minimizing the transport of airborne infectious diseases such as Covid-19 and SARS in the hospital ward. The goal of this study is to explore elimination strategies for an efficient removal of contaminated agents, targeting the influence of using local air diffuser and exhaust. Computational Fluid Dynamics (CFD) technique was used to model the airflow field and contamination distribution in the ward environment. Simulated results showed that the bacteria spread from a patient confined to his bed was limited and under certain conditions significantly eliminated. Consequently, a relatively high efficiency of particle removal and a moderated transmission were obtained. Thus, this strategy is able to shorten the exposure time of patient and healthcare staff, as a result, mitigating cross-infection risk at the hospital.
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| 2. |
- Desjardins, Kewin, et al.
(författare)
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Characterization of a back-illuminated CMOS camera for soft x-ray coherent scattering
- 2019
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Ingår i: Proceedings of the 13th International Conference on Synchrotron Radiation Instrumentation, SRI 2018. - : Author(s). - 9780735417823 ; 2054
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Konferensbidrag (refereegranskat)abstract
- A commercial scientific camera has been adapted and characterized at the SOLEIL Synchrotron with the aim to improve the acquisition capabilities on the soft X-ray coherent scattering experimental station at SEXTANTS beamline. This device is equipped by the last generation of back side illuminated scientific CMOS (BSI-sCMOS) of 2048 by 2048 pixels of 11 μm2 able to acquire low noise images with a frame rate up to 48 Hz. The camera's performance measurements have been done and shows a good level of readout noise, a large full-well capacity, a medium dark current and a good homogeneity, respectively, 1.6 e- rms (in High Gain mode), 80 000 e- (in Low Gain mode),<5 e-/pixel/s and ∼ 1%. The quantum efficiency (QE) measurement has been performed at the soft x-ray branch of the METROLOGIE beamline and gives a relatively good agreement with the expected theoretical values. Finally, the demonstration of the camera's efficiency and of the gain in useful time measurement related to the high frame rate have been performed with a series of Airy patterns images compared with an image recorded using the standard BSI-CDD already in operation at the SEXTANTS beamline.
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| 3. |
- Griesmayer, E., et al.
(författare)
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Applications of single-crystal CVD diamond XBPM detectors with nanometre x-ray beams
- 2019
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Ingår i: Proceedings of the 13th International Conference on Synchrotron Radiation Instrumentation, SRI 2018. - : Author(s). - 9780735417823 ; 2054
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Konferensbidrag (refereegranskat)abstract
- Measurements with a Diamond XBPM were carried out at the MAX IV Laboratory, Lund, Sweden, at the NanoMAX beam line. This was the first investigation of a Diamond XBPM detector with nanometre beams. The effect of diffusion, as well as the position resolution at the smallest available beam sizes were studied.
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| 4. |
- Holmberg, Sture, et al.
(författare)
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Drug-resistant bacteria in hospital wards - the role of ventilation
- 2009
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Ingår i: 9th International Conference and Exhibition - Healthy Buildings 2009, HB 2009. ; , s. 596-
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Konferensbidrag (refereegranskat)abstract
- To limit the airborne spread of infectious agents (antibiotic-resistant bacteria) in hospital wards is an increasing world-wide concern. A multi-disciplinary Swedish research team is together with industry focusing on this problem. New knowledge is sought on how building ventilation services should be designed to minimize the risk of airborne infectious agents. In the literature there is strong and sufficient evidence to demonstrate the association between ventilation, air movements in buildings and the transmission/spread of diseases. There is, however, insufficient data to specify and quantify the minimum ventilation requirements in relation to the spread of infectious diseases via the airborne route. The latest developments in the advanced numerical simulation (CFD) methods offer new possibilities to follow the routes of airborne contaminants. Many ventilation parameters, including air flow rates, thermal and pressure conditions as well as the behavior of persons in the room are analyzed. The influence of both local air supply and local air exhaust has been analyzed and very promising results from this part of the work are presented. A bacterium spread from a patient confined to his bed was limited and for certain conditions almost eliminated. Ventilation and spatial parameter combinations to limit and prevent the spread of contaminants are mapped for different hospital wards. The risk of airborne transmission is modeled and discussed. Implementation in practice is sought via close collaboration with industry.
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| 5. |
- Marcouille, O., et al.
(författare)
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Production of high energy photons with in vacuum wigglers : From SOLEIL wiggler to MAXIV wiggler
- 2019
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Ingår i: Proceedings of the 13th International Conference on Synchrotron Radiation Instrumentation, SRI 2018. - : Author(s). - 9780735417823 ; 2054
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Konferensbidrag (refereegranskat)abstract
- Small gap wigglers become more and more attractive to produce high photon fluxes in the hard X-ray photon range. They use magnet blocks of high magnetization which resists much better to heating (baking, synchrotron radiation) than in the past, produce high magnetic field with numerous periods and are very compact. They also are a very good alternative to superconducting technology which requires special infrastructure, heavy maintenance and is not running cost free. SOLEIL, operating presently at 2.75 GeV has designed and built an in-vacuum wiggler of 38 periods of 50 mm producing 2.1 T at a minimum gap of 5.5 mm to delivered photon beam between 20 keV and 50 keV. Already in operation, further improvements are presently in progress to push photons towards higher energy, in particular thanks to the operation at lower gap (4.5 mm). MAX IV and SOLEIL, in the frame of collaboration, ave built an upgraded version of the existing SOLEIL wiggler with the target to extend the spectral range at high energy (above 50 keV) but also at low energy (4 keV) with the same insertion device. The design of the existing magnetic system has been modified to reach 2.4 T at a minimum gap of 4.2 mm and includes taper operation to avoid undulator structure in the radiated spectrum at low energy.
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| 6. |
- Plivelic, Tomás S., et al.
(författare)
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X-ray tracing, design and construction of an optimized optics scheme for CoSAXS, the small angle x-ray scattering beamline at MAX IV laboratory
- 2019
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Ingår i: Proceedings of the 13th International Conference on Synchrotron Radiation Instrumentation, SRI 2018. - : Author(s). - 9780735417823 ; 2054
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Konferensbidrag (refereegranskat)abstract
- A novel optical design for a flexible SAXS beamline at a modern synchrotron has been implemented for the CoSAXS beamline at the 3GeV ring at the MAX TV Laboratory. The performance of the beamline has been simulated through combined ray tracing and wave propagation with the code xrt taking into account the low emittance and highly coherent beam of MAX TV and the short inter-optics distances of the beamline. The total photon flux is estimated to be 1012-1013 ph/s with the coherent flux portion up to 10 % at 7.1 keV. The inhomogeneities in the X-ray beam arising from use of real (non-idealised) mirror surfaces are also modelled using the measured slope profiles of the mirrors. Strategies to mitigate these inhomogeneities are discussed. The optical components for CoSAXS have been constructed and beamline commissioning will start in 2019.
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| 7. |
- Reza, Bagger, et al.
(författare)
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RF LDMOS Power Amplifier Integrated Circuits for Cellular Wireless Base Station Applications
- 2006
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Konferensbidrag (refereegranskat)abstract
- Three broadband RF LDMOS Power Amplifier Integrated Circuits (PA ICs) for cellular base station applications have been developed in Si LDMOS IC technologies. They can be used for all typical modulation formats from 800 MHz to 2300 MHz, and power levels from 30 W to 50 W depending on application. GSM/EDGE PA IC achieved 35 dB gain and 30 W with 200 MHz bandwidth (22% bandwidth) at 900_MHz. CDMA2000 PA IC achieved 30 dB gain and 40 W with 300 MHz bandwidth (15% bandwidth) at 1900 MHz. TD-SCDMA/WCDMA PA IC achieved 27 dB gain and 50 W under TD-SCDMA signal and 40 W under WCDMA signal with 400 MHz bandwidth (20% bandwidth) at 2100 MHz. All three PA ICs have been characterized under all typical modulations formats and showed excellent linear power, efficiency, and bandwidth. The excellent performances of these three PA ICs, simplify power amplifier designs, enable a small footprint and help lower the cost of the modern base-station.
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| 8. |
- Silvervarg, Annika, 1974-, et al.
(författare)
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Assessment of Students' Feedback Behavior in A Game-Based Automated Feedback System-A Cross-Cultural Replication Study
- 2022
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Ingår i: 30th International Conference on Computers in Education Conference, ICCE 2022 - Proceedings. - Kuala Lumpur, Malaysia. - 9789869721493 ; , s. 292-301
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Konferensbidrag (refereegranskat)abstract
- In this paper, we argue for the importance of conducting replication studies over various schools and countries when addressing topics about learning and instruction and propose educational technology to be a tool for this endeavor. We present an example of a cross-cultural replication study that makes use of educational technology in the form of a digital game-based automated feedback system. The study addresses feedback related behavior in 11-15-year-old students in US and Swedish classrooms, investigating students' choices to seek confirmatory (i.e., positive) or critical (i.e., negative) feedback, as well as their subsequent choices to revise their work based on this feedback. Comparisons of the data collected at several schools in the US and Sweden showed similar patterns of relationships among students' feedback-seeking behavior, their tendency to revise their work, and their learning outcomes in and outside the assessment environment. Overall, the findings revealed that this assessment approach seems to be generalizable from a North American to a European population. However, the findings showed both a significant difference between Sweden and the US regarding the preference for critical feedback and between different schools within each country. Thus, it is possible that the difference between countries reflects school differences rather than cultural differences.
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| 9. |
- Ternblad, Eva Maria, et al.
(författare)
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I will help you, but will you help me? How the Perception of a Teachable Agent May Influence Performance
- 2022
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Ingår i: 30th International Conference on Computers in Education Conference, ICCE 2022 - Proceedings. - 9789869721493 ; , s. 63-72
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Konferensbidrag (refereegranskat)abstract
- Learning by teaching someone else has proven to be beneficial in both human-human and human-agent interaction. Instructing someone else, that is, taking the role as a tutor, has a series of positive effects on students' learning and performance. For example, the fact that someone else is in need of help seems to affect students to put more effort into the task at hand, trying harder, being more thorough and persisting longer. This has inspired researchers to design educational software that uses teachable agents (TAs). The use of such software has shown to improve students'-not the least lower-achieving students'-learning. Designing teachable agents is, however, a delicate matter since the personality and capability of the agent may affect students' behaviors and performance. This study, which includes data from 156 6th grade students who used an educational game in history during three lessons, contributes to research on how students' perceptions of a neutral TA (without any specific personality and behavior) may influence their performance. The focus is on whether and how students' learning gains are influenced by the extent to which students perceive their TA as someone who does need their help. In addition, we explored whether such potential effects would differ between lower- and higher-achieving students. Results were that students' perceptions about the TA's need for help was a significant predictor of high performance (based on in-game performance and post-test scores)-independent of their general achievement level (grounded in the students' reading proficiency). In other words, all students, whether lower- or higher-achieving, benefitted from being convinced of the agent's need for help. This finding is somewhat different from previous studies, where TAs mainly have been found to be beneficial for lower-achieving students. In relation to this, the present study adds a novel piece of information by suggesting that for TAs to be beneficial in educational software, their need for help should be clearly communicated and emphasized. This, on the other hand, may make them useful for all students, independently of how well they usually perform in school.
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| 10. |
- Ternblad, Eva Maria, et al.
(författare)
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Understanding Areas of Parallelograms Through Virtual Geometrical Representations : A Pilot Study
- 2022
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Ingår i: 30th International Conference on Computers in Education Conference, ICCE 2022 - Proceedings. - 9789869721493 ; , s. 206-209
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Konferensbidrag (refereegranskat)abstract
- Do virtual representations, intended for teaching and learning, afford different constraints and affordances compared to their physical twins, and may this lead to different ways of interaction and understanding? In this line of inquiry, and with the perspective on learning as an extended activity, where learning can be mediated through the interaction with artefacts, the present study has translated the concrete material from a 30-year-old study on geometry to a digital application with virtual geometrical manipulatives. 26 students from the 6th grade worked with the software for two lessons and thereafter completed a test. Learning outcomes are presented and compared to those from the original study, revealing not only substantially less learning gains, but also other unexpected differences.
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