| 1. |
- Bergström, Malin, et al.
(författare)
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Narrative review of interventions suitable for well-baby clinics to promote infant attachment security and parents' sensitivity
- 2020
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Ingår i: Acta Paediatrica. - : Wiley. - 0803-5253 .- 1651-2227. ; 109:9, s. 1745-1757
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Tidskriftsartikel (refereegranskat)abstract
- Aim The aim of this narrative review was to evaluate the evidence for interventions for children's secure attachment relationships and parents' caregiving sensitivity that could potentially be implemented in the context of a well-baby clinic. Methods Literature search on programmes for parental caregiving sensitivity and secure attachment for infants aged 0-24 months. Randomised controlled trials (RCTs) published 1995-2018 with interventions starting from one week postpartum, and with a maximum of 12 sessions (plus potential booster session) were included. Results We identified 25 studies, of which 22 studied effects of home-based programmes using video feedback techniques. Positive effects of these interventions in families at risk were found on parental caregiving sensitivity and to a lesser extent also on children's secure or disorganised attachment. The effects of two of these programmes were supported by several RCTs. Three intervention studies based on group and individual psychotherapy showed no significant positive effects. Most of the interventions targeted mothers only. Conclusions The review found some evidence for positive effects of selective interventions with video feedback techniques for children's secure attachment and strong evidence for positive effects on parental caregiving sensitivity. Important knowledge gaps were identified for universal interventions and interventions for fathers and parents with a non-Western background.
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| 2. |
- Berkowicz, Sharon
(författare)
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The Role of Molecular Heterogeneity in the Structural Dynamics of Aqueous Solutions
- 2022
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Aqueous solutions constitute the basis of life, yet their complex and anomalous nature is far from well-understood. Transient molecular ordering gives rise to microscopic spatial liquid heterogeneities and fluctuations which are believed to play a key role in biochemical processes as well as in pure water, the latter of which could fundamentally alter our view on water as life's solvent. In this thesis, we experimentally investigate the structural dynamics in aqueous solutions with the aim to understand the role of molecular heterogeneity in the complex solution dynamics. To extract dynamic information, we utilize coherent light- and X-ray scattering techniques, such as dynamic light scattering (DLS) and X-ray photon correlation spectroscopy (XPCS), which can resolve structural dynamics on a broad range of length and time scales. We explore the influence of hypothesized water fluctuations in the dynamics of simple model solutes, finding that their diffusive dynamic behaviour is effectively similar and independent of solute size down to molecular scale, whilst significantly different from that of single water molecules. Secondly, in a first proof-of-concept experiment, we successfully combine the spatial resolution of nanofocused coherent X-ray beams with dynamic measurements by XPCS, the results of which indicate that `nano-XPCS' could prove a valuable tool in the quest to resolve nanoscale fluctuations. Finally, an outlook is given where the next steps in these investigations are discussed, such as the use of aqueous-organic mixtures as model systems for spatially heterogeneous dynamics in biological solutions.
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| 3. |
- Bohm, Christian, et al.
(författare)
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A MHz-repetition-rate hard X-ray free-electron laser driven by a superconducting linear accelerator
- 2020
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Ingår i: Nature Photonics. - : Springer Science and Business Media LLC. - 1749-4885 .- 1749-4893. ; 14:6, s. 391-397
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Tidskriftsartikel (refereegranskat)abstract
- The European XFEL is a hard X-ray free-electron laser (FEL) based on a high-electron-energy superconducting linear accelerator. The superconducting technology allows for the acceleration of many electron bunches within one radio-frequency pulse of the accelerating voltage and, in turn, for the generation of a large number of hard X-ray pulses. We report on the performance of the European XFEL accelerator with up to 5,000 electron bunches per second and demonstrating a full energy of 17.5 GeV. Feedback mechanisms enable stabilization of the electron beam delivery at the FEL undulator in space and time. The measured FEL gain curve at 9.3 keV is in good agreement with predictions for saturated FEL radiation. Hard X-ray lasing was achieved between 7 keV and 14 keV with pulse energies of up to 2.0 mJ. Using the high repetition rate, an FEL beam with 6 W average power was created. The first operation of the European X-ray free-electron laser facility accelerator based on superconducting technology is reported. The maximum electron energy is 17.5 GeV. A laser average power of 6 W is achieved at a photon energy of 9.3 keV.
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| 4. |
- Brunsell, Per, et al.
(författare)
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Initial results from the rebuilt EXTRAP T2R RFP device
- 2001
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Ingår i: Plasma Physics and Controlled Fusion. - BRISTOL. ENGLAND : IOP PUBLISHING LTD. - 0741-3335 .- 1361-6587. ; 43:11, s. 1457-1470
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Tidskriftsartikel (refereegranskat)abstract
- The EXTRAP T2R thin shell reversed-field pinch (RFP) device has recently resumed operation after a major rebuild including the replacement of the graphite armour with molybdenum limiters, a fourfold increase of the shell time constant, and the replacement of the helical coil used for the toroidal field with a conventional solenoid-type coil. Wall-conditioning using hydrogen glow discharge cleaning was instrumental for successful RFP operation. Carbon was permanently removed from the walls during the first week of operation. The initial results from RFP operation with relatively low plasma currents in the range I-p = 70-100 kA are reported. RFP discharges are sustained for more than three shell times. Significant improvements in plasma parameters are observed, compared to operation before the rebuild. There is a substantial reduction in the carbon impurity level. The electron density behaviour is more shot-to-shot reproducible. The typical density is n(e) = 0.5-1 x 10(19) m(-3). Monitors of H-alpha line radiation indicate that the plasma wall interaction is more toroidally symmetric and that there is less transient gas release from the wall. The minimum loop voltage is in the range V-t = 28-35 V, corresponding to a reduction by a factor of two to three compared to the value before the rebuild.
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| 5. |
- Brunsell, Per R., et al.
(författare)
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Reversed field pinch operation with intelligent shell feedback control in EXTRAP T2R
- 2006
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 46:11, s. 904-913
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Tidskriftsartikel (refereegranskat)abstract
- Discharges in the thin shell reversed field pinch (RFP) device EXTRAP T2R without active feedback control are characterized by growth of non-resonant m = 1 unstable resistive wall modes (RWMs) in agreement with linear MHD theory. Resonant m = 1 tearing modes (TMs) exhibit initially fast rotation and the associated perturbed radial fields at the shell are small, but eventually TMs wall-lock and give rise to a growing radial field. The increase in the radial field at the wall due to growing RWMs and wall-locked TMs is correlated with an increase in the toroidal loop voltage, which leads to discharge termination after 3-4 wall times. An active magnetic feedback control system has been installed in EXTRAP T2R. A two-dimensional array of 128 active saddle coils (pair-connected into 64 independent m = 1 coils) is used with intelligent shell feedback control to suppress the m = 1 radial field at the shell. With feedback control, active stabilization of the full toroidal spectrum of 16 unstable m = 1 non-resonant RWMs is achieved, and TM wall locking is avoided. A three-fold extension of the pulse length, up to the power supply limit, is observed. Intelligent shell feedback control is able to maintain the plasma equilibrium for 10 wall times, with plasma confinement parameters sustained at values comparable to those obtained in thick shell devices of similar size.
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| 6. |
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| 7. |
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| 8. |
- Falowska-Pietrzak, Olga, 1995-
(författare)
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Absorbed dose and fluence measurements and simulations at EuXFEL undulator systems
- 2023
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The European X-Ray Free Electron Laser generates X-ray pulsesas GeV electrons progress in the beam pipe through periodic arrangements of magnets called undulators. An undesired scattered radiation (stray radiation) is also present outside the beam pipe. It may damage not only undulator magnets, but also diagnostic and correction equipment located near undulators. It results in decreased performance of the EuXFEL. As the severity of magnet damage differs for different particles and energies, it is of great importance to properly characterize the stray radiation field in the vicinity of the undulators. In this thesis, results of Gafchromic film dose measurements near EuXFEL undulators are presented. Films were placed at the entrance of the undulator segments, along the undulator permanent magnets and at the front of phase shifters located in the intersections separating two undulator segments. In addition, Monte Carlo simulations of absorbed dose and fluence were performed with Geant4 toolkit to characterize the composition and energy spectra of the radiation field near undulators. Comparison of film measurements and simulations show that theradiation field near the upstream undulator cells may be a result of high-energy electrons interactions with the beam pipe. Almost 99 % of the dose absorbed to the permanent magnets comes from electrons and positrons created through photon interactions with matter. However, the majority of particles are photons. In addition,simulations show that neutrons are also presented within the magnets. Significant doses were measured further away from thepermanent magnets, close to phase shifters installed in the intersections.
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| 9. |
- Falowska-Pietrzak, Olga, et al.
(författare)
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Investigation of the stray radiation origin and composition at the European XFEL undulators with gafchromic films measurements and Geant4 simulations
- 2023
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - 0168-9002 .- 1872-9576. ; 1056
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Tidskriftsartikel (refereegranskat)abstract
- At EuXFEL, a stray field of ionizing radiation is present near undulator magnets which eventually can lead to their demagnetization and decreased efficiency of the Self-Amplified Spontaneous Emission (SASE) process. In this work we investigate both the origin and composition of the radiation field at the undulator magnets with gafchromic film measurements and Geant4 Monte Carlo simulations. Both measurements and simulations suggest that the radiation field in the upstream undulator cells comes from high-energy electrons striking the beam pipe. In addition, horizontal dose distributions at the entrance of the undulator segments depend on where the electrons hit the beam pipe. Geant4 simulations show that the radiation fluence near magnets is dominated by photons, while charged secondary electrons and positrons contribute almost entirely to the ionizing dose absorbed by magnets.
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| 10. |
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Fjärde nationella konferensen i svenska med didaktisk inriktning : Tala, lyssna, skriva, läsa, lära – modersmåls-ndervisning i ett nordiskt perspektiv, Umeå 16–17 november 2006
- 2007
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Proceedings (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- Temat för konferensen i Umeå var ”Tala, lyssna, skriva, läsa, lära – modersmålsundervisning i ett nordiskt perspektiv”. De inledande fem honnörsorden i rubriken var inte tänkta som ett eko ur det förflutna, det vill säga från momentsplittringen i de gamla Lgr 69 och Lgy 70, utan fick ge namn åt parallella sessioner där svenskämnets helhet var en självklar utgångspunkt. Forskning om elevers språkutveckling i vid mening stimuleras av en vidare didaktisk syn som inte begränsas till enbart modersmålsundervisning. Forskning om hur man talar, lyssnar, läser och skriver i inlärningssituationer är något vi vill tro kan komma all undervisning till del.Det finns en risk med att sätta ’språkutveckling’ i fokus, som om studier inom fältet Svenska med didaktisk inriktning vore renodlat språkinriktade. Så är det inte. Forskning om hur skönlitteratur, och andra kommunikationsformer, kommer in i klassrummet är ett centralt forskningsområde som Nätverket vill stödja, vilket läsaren av denna konferensvolym kommer att upptäcka. Rapporter från projektet ”Den skönlitterära texten i skola och lärarutbildning” liksom samtal om framtida möjliga projekt var uppskattade inslag i konferensen. Svenska är det största ämnet i skolan, med vilka mått man än mäter och vilka aspekter man än betonar. I skolämnet Svenska ingår språk- och litteraturstudier. En lektor och lärarutbildare har än så länge normalt bara fördjupad kompetens i en av ämnets delar. Framväxten av forskarutbildning inom Svenska med didaktisk inriktning innebär på sikt en dubblering av kompetensen. Glädjande nog deltog flera doktorander och disputerade inom fältet Svenska med didaktisk inriktning i konferensen, vilket också avspeglas i denna volym.Ett utvecklat samarbete mellan universitetsämnena nordiska språk och litteraturvetenskap samt med Lärarutbildningen är en självklar förutsättning för utbildning av kvalificerade svensklärare. Vid Umeå universitet studeras nordiska språk och litteraturvetenskap vid en och samma institution, en lösning som bidragit till ett fördjupat samarbete i lärarutbildningen. Representanter från lärarutbildning, litteraturvetenskap och nordiska språk ingår också i ledningsgruppen för Nätverket, vilket bidragit till att arbetet med konferensen och konferensvolymen varit stimulerande och verklighetsförankrat.Svenskämnets storlek och betydelse gör att behovet av forskning inom både ungdomsskola, lärarutbildningar och andra inlärningssituationer är mycket stort. Nätverkets konferenser ska stimulera till adekvat forskning inom området och vara en naturlig mötesplats för forskare att presentera sina rön. Med konferensvolymen från Smdi:s fjärde konferens tar vi ännu ett steg framåt. Plenarföredragen får inleda volymen, varefter sektionsföredragen kommer i bokstavsordning.
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