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- Petersson, C. L.M., et al.
(författare)
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Anisotropic photoemission time delays close to a Fano resonance
- 2018
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Electron correlation and multielectron effects are fundamental interactions that govern many physical and chemical processes in atomic, molecular and solid state systems. The process of autoionization, induced by resonant excitation of electrons into discrete states present in the spectral continuum of atomic and molecular targets, is mediated by electron correlation. Here we investigate the attosecond photoemission dynamics in argon in the 20-40 eV spectral range, in the vicinity of the 3s(-1)np autoionizing resonances. We present measurements of the differential photoionization cross section and extract energy and angle-dependent atomic time delays with an attosecond interferometric method. With the support of a theoretical model, we are able to attribute a large part of the measured time delay anisotropy to the presence of autoionizing resonances, which not only distort the phase of the emitted photoelectron wave packet but also introduce an angular dependence.
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2. |
- Petersson, C. L M, et al.
(författare)
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Phase metrology with multi-cycle two-colour pulses
- 2016
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Ingår i: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 49:9
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Tidskriftsartikel (refereegranskat)abstract
- Strong-field phenomena driven by an intense infrared (IR) laser depend on during what part of the field cycle they are initiated. By changing the sub-cycle character of the laser electric field it is possible to control such phenomena. For long pulses, sub-cycle shaping of the field can be done by adding a relatively weak, second harmonic of the driving field to the pulse. Through constructive and destructive interference, the combination of strong and weak fields can be used to change the probability of a strong-field process being initiated at any given part of the cycle. In order to control sub-cycle phenomena with optimal accuracy, it is necessary to know the phase difference of the strong and the weak fields precisely. If the weaker field is an even harmonic of the driving field, electrons ionized by the field will be asymmetrically distributed between the positive and negative directions of the combined fields. Information about the asymmetry can yield information about the phase difference. A technique to measure asymmetry for few-cycle pulses, called stereo-ATI (above threshold ionization), has been developed by Paulus et al (2003 Phys. Rev. Lett. 91 253004). This paper outlines an extension of this method to measure the phase difference between a strong IR and its second harmonic.
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3. |
- Wengström, Yvonne, 1959-, et al.
(författare)
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Developing patient reported outcome measures (PROM) for implementation in the Swedish National Breast Cancer Quality Register
- 2013
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Ingår i: European Journal of Cancer. - 0959-8049 .- 1879-0852. ; 49, s. S329-S329
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Tidskriftsartikel (refereegranskat)abstract
- Background: The local authorities for health and welfare support the introduction of Patient Reported Outcome Measures (PROM) in the quality registers in Sweden. Valid and reliable instruments measuring PROM do not exist that could be used throughout the whole breast cancer process. We sought to develop and implement PROM for breast cancer at different stages in the disease course in different Swedish geographic regions for later use in the Swedish National Quality Register for breast cancer. The aim was to develop appropriate PROM to assess symptoms and problems among patients with breast cancer about one year after diagnosis.Materials and Methods: A scoping review and focus group discussions were conducted with women invited by the breast cancer association Amazona (Stockholm). The symptoms that emerged from the scoping review and focus group discussions formed the basis for the development of a web based questionnaire consisting of validated instruments (EORTC QLQ-C30, BR 23, MSAS) for measuring PROM. The women who participated in the focus group discussions were invited to respond to a pilot version of the web based questionnaire. The results were used to revise the web based questionnaire. An invitation was sent to a national random sample from the Swedish National Breast Cancer Quality Register diagnosed one year earlier to respond to the revised version of the web based questionnaire.Results: The results will present the work process of the development of the PROM as well as plans for further work on the implementation of the PROM in the Swedish National Quality Register for breast cancer. Preliminary data shows that about 70% responded to the revised version of the web based questionnaire. However, some women requested a paper version of the questionnaire mostly because they did not have access to a computer.Conclusion: In the development of PROM in quality registers it is important to include patients experiences in order to develop relevant outcome measures to influence the quality of the health care delivery.
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