| 1. |
- Maroju, P. K., et al.
(författare)
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Analysis of two-color photoelectron spectroscopy for attosecond metrology at seeded free-electron lasers
- 2021
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Ingår i: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 23:4
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Tidskriftsartikel (refereegranskat)abstract
- The generation of attosecond pulse trains at free-electron lasers opens new opportunities in ultrafast science, as it gives access, for the first time, to reproducible, programmable, extreme ultraviolet (XUV) waveforms with high intensity. In this work, we present a detailed analysis of the theoretical model underlying the temporal characterization of the attosecond pulse trains recently generated at the free-electron laser FERMI. In particular, the validity of the approximations used for the correlated analysis of the photoelectron spectra generated in the two-color photoionization experiments are thoroughly discussed. The ranges of validity of the assumptions, in connection with the main experimental parameters, are derived.
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| 2. |
- Finetti, P., et al.
(författare)
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Pulse duration of seeded free electron lasers
- 2017
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Ingår i: Physical Review X. - 2160-3308. ; 7:2
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Tidskriftsartikel (refereegranskat)abstract
- The pulse duration, and, more generally, the temporal intensity profile of free-electron laser (FEL) pulses, is of utmost importance for exploring the new perspectives offered by FELs; it is a nontrivial experimental parameter that needs to be characterized. We measured the pulse shape of an extreme ultraviolet externally seeded FEL operating in high-gain harmonic generation mode. Two different methods based on the cross-correlation of the FEL pulses with an external optical laser were used. The two methods, one capable of single-shot performance, may both be implemented as online diagnostics in FEL facilities. The measurements were carried out at the seeded FEL facility FERMI. The FEL temporal pulse characteristics were measured and studied in a range of FEL wavelengths and machine settings, and they were compared to the predictions of a theoretical model. The measurements allowed a direct observation of the pulse lengthening and splitting at saturation, in agreement with the proposed theory.
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| 3. |
- Grazioli, V.S., et al.
(författare)
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Injunctive norms of alcohol-related consequences among high school students : impact on alcohol outcomes
- 2013
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Ingår i: Alcoholism. - : John Wiley & Sons. - 0145-6008 .- 1530-0277. ; 37:s2, s. 156A-156A
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Literature indicates that high school students experience numerous negative consequences related to drinking (Miller, Naimi, Brewer, & Jones, 2007). It is therefore important to understand determinants of drinking behaviors in this population, such as injunctive norms (i.e., perception of self and/or others’ approval of a specific behavior; Cialdini et al., 1990). A recent study among college students documented a discrepancy between personal attitudes about alcohol-related consequences and perceived attitudes of peers, with students perceiving peers to be more approving of alcohol-related consequences than themselves, which predicted higher rates of alcohol use (DeMartini, Carey, Lao, & Luciano, 2011). To our knowledge, this has not been studied among high school students. Thus, the purpose of the current study is to evaluate the predictive role of perceived differences in injunctive norms between self and peers for alcohol-related consequences among high school seniors. The sample included 3,352 students in the US (n = 1181, 57.7%female) and Sweden (n = 2171, 55.9% female), participating in an international longitudinal study about alcohol use trajectories. Measures included injunctive norms for self and friends for alcohol-related consequences (i.e., 7 items adapted from the RAPI; White & Labouvie, 1989), alcohol-related consequences (RAPI; White & Labouvie, 1989), and alcohol use (DDQ; Collins, Parks, & Marlatt, 1985). Paired samples t-tests were used to compare mean injunctive norms for self (M = 1.78), and friends (M = 2.02). There was a significant difference in perceived attitudes between self and friends (t (3173) = -17.76, p < .001) such that injunctive norms for self were lower than for friends. Next, regression analyses evaluated the discrepancy in injunctive norms for self and friends and its relation to alcohol outcomes. Differences between self and friends were computed by subtracting self from friends (F-S). F-S significantly predicted total drinks per week (b = .11, F (1, 3059) = 40.27, p < .001), average drinks per drinking occasion (b = .08, F (1, 3059) = 17.37, p < .001), and negative consequences (b = .21, F (1, 3113) = 143.09, p < .001). These results provide additional support of the importance of injunctive norms of alcohol-related consequences in young adults and have implications for prevention programs tailored to high school students. This research was supported by NIAAA #U01 AA018276 awarded to Drs. Larimer & Berglund.
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