| 531. |
- Prasciolu, Mauro, et al.
(författare)
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On the use of multilayer Laue lenses with X-ray free electron lasers
- 2021
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Ingår i: International Conference on X-Ray Lasers 2020. - : SPIE. - 0277-786X .- 1996-756X. - 9781510646186 ; 11886
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Konferensbidrag (refereegranskat)abstract
- We report on the use of multilayer Laue lenses to focus the intense X-ray Free Electron Laser (XFEL) beam at the European XFEL to a spot size of a few tens of nanometers. We present the procedure to align and characterize these lenses and discuss challenges working with the pulse trains from this unique X-ray source.
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| 532. |
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| 533. |
- Robbie, K., et al.
(författare)
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Formation of Ni-graphite intercalation compounds on SiC
- 2001
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - : American Physical Society. - 1098-0121 .- 1550-235X. ; 64, s. 155401-15540111
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Tidskriftsartikel (refereegranskat)
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| 534. |
- Robbie, K, et al.
(författare)
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Study of contact formation by high temperature deposition of Ni on SiC
- 2000
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Ingår i: Materials Science Forum. - 0255-5476 .- 1662-9752. ; 338-3, s. 981-984
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Tidskriftsartikel (refereegranskat)abstract
- We report the observation, by scanning tunneling microscopy (STM), scanning electron microscopy (SEM), Auger electron spectroscopy (AES), and atomic force microscopy (AFM), of island formation on SIC during high temperature deposition and annealing of thin Ni films. Ni films with a nominal thickness of 2.5 monolayers were sputter deposited onto H-2-etched single crystal 6H-SiC (0001) substrates heated to 600 degreesC in an ultrahigh vacuum STM system. After the substrates were annealed to 800-1000 degreesC, island formation was observed by STM. The islands were 0.1-0.5 mum in diameter, similar to 30 nm high, and separated by similar to2 mum from each other, with an exceptionally flat top with a peculiar 'stitched' surface structure. A second type of island, similar to1.5 mum in diameter, similar to 10 nm high, and separated by similar to 10 mum from each other, was observed by ex situ AFM and SEM. Microspot AES showed that the first islands are composed of Ni and C, while the second islands are composed of Ni, C, and Si. AES lineshape studies showed that the carbon in both types of islands is graphitically bound as opposed to the carbon in the substrate which is carbidically bound. From comparisons to literature, we believe that the first islands are a new type of graphite intercalation compound. An indexing of Ni on the top graphite sheets is presented for each anneal temperature.
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| 535. |
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| 536. |
- Schweinsberg, Martin, et al.
(författare)
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Same data, different conclusions : Radical dispersion in empirical results when independent analysts operationalize and test the same hypothesis
- 2021
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Ingår i: Organizational Behavior and Human Decision Processes. - : Elsevier BV. - 0749-5978 .- 1095-9920. ; 165, s. 228-249
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Tidskriftsartikel (refereegranskat)abstract
- In this crowdsourced initiative, independent analysts used the same dataset to test two hypotheses regarding the effects of scientists' gender and professional status on verbosity during group meetings. Not only the analytic approach but also the operationalizations of key variables were left unconstrained and up to individual analysts. For instance, analysts could choose to operationalize status as job title, institutional ranking, citation counts, or some combination. To maximize transparency regarding the process by which analytic choices are made, the analysts used a platform we developed called DataExplained to justify both preferred and rejected analytic paths in real time. Analyses lacking sufficient detail, reproducible code, or with statistical errors were excluded, resulting in 29 analyses in the final sample. Researchers reported radically different analyses and dispersed empirical outcomes, in a number of cases obtaining significant effects in opposite directions for the same research question. A Boba multiverse analysis demonstrates that decisions about how to operationalize variables explain variability in outcomes above and beyond statistical choices (e.g., covariates). Subjective researcher decisions play a critical role in driving the reported empirical results, underscoring the need for open data, systematic robustness checks, and transparency regarding both analytic paths taken and not taken. Implications for orga-nizations and leaders, whose decision making relies in part on scientific findings, consulting reports, and internal analyses by data scientists, are discussed.
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| 537. |
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| 538. |
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| 539. |
- Sztuk-Dambietz, J., et al.
(författare)
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Operational experience with Adaptive Gain Integrating Pixel Detectors at European XFEL
- 2024
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Ingår i: Frontiers in Physics. - : Frontiers Media SA. - 2296-424X. ; 11
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Forskningsöversikt (refereegranskat)abstract
- The European X-ray Free Electron Laser (European XFEL) is a cutting-edge user facility that generates per second up to 27,000 ultra-short, spatially coherent X-ray pulses within an energy range of 0.26 to more than 20 keV. Specialized instrumentation, including various 2D X-ray detectors capable of handling the unique time structure of the beam, is required. The one-megapixel AGIPD (AGIPD1M) detectors, developed for the European XFEL by the AGIPD Consortium, are the primary detectors used for user experiments at the SPB/SFX and MID instruments. The first AGIPD1M detector was installed at SPB/SFX when the facility began operation in 2017, and the second one was installed at MID in November 2018. The AGIPD detector systems require a dedicated infrastructure, well-defined safety systems, and high-level control procedures to ensure stable and safe operation. As of now, the AGIPD1M detectors installed at the SPB/SFX and MID experimental end stations are fully integrated into the European XFEL environment, including mechanical integration, vacuum, power, control, data acquisition, and data processing systems. Specific high-level procedures allow facilitated detector control, and dedicated interlock systems based on Programmable Logic Controllers ensure detector safety in case of power, vacuum, or cooling failure. The first 6 years of operation have clearly demonstrated that the AGIPD1M detectors provide high-quality scientific results. The collected data, along with additional dedicated studies, have also enabled the identification and quantification of issues related to detector performance, ensuring stable operation. Characterization and calibration of detectors are among the most critical and challenging aspects of operation due to their complex nature. A methodology has been developed to enable detector characterization and data correction, both in near real-time (online) and offline mode. The calibration process optimizes detector performance and ensures the highest quality of experimental results. Overall, the experience gained from integrating and operating the AGIPD detectors at the European XFEL, along with the developed methodology for detector characterization and calibration, provides valuable insights for the development of next-generation detectors for Free Electron Laser X-ray sources.
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| 540. |
- Theorell, Töres, et al.
(författare)
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Job strain in relation to body mass index : pooled analysis of 160 000 adults from 13 cohort studies
- 2012
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 272:1, s. 65-73
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Tidskriftsartikel (refereegranskat)abstract
- Job strain in relation to body mass index: pooled analysis of 160 000 adults from 13 cohort studies. J Intern Med 2012; 272: 6573. Background. Evidence of an association between job strain and obesity is inconsistent, mostly limited to small-scale studies, and does not distinguish between categories of underweight or obesity subclasses. Objectives. To examine the association between job strain and body mass index (BMI) in a large adult population. Methods. We performed a pooled cross-sectional analysis based on individual-level data from 13 European studies resulting in a total of 161 746 participants (49% men, mean age, 43.7 years). Longitudinal analysis with a median follow-up of 4 years was possible for four cohort studies (n = 42 222). Results. A total of 86 429 participants were of normal weight (BMI 18.524.9 kg m-2), 2149 were underweight (BMI < 18.5 kg m-2), 56 572 overweight (BMI 25.029.9 kg m-2) and 13 523 class I (BMI 3034.9 kg m-2) and 3073 classes II/III (BMI = 35 kg m-2) obese. In addition, 27 010 (17%) participants reported job strain. In cross-sectional analyses, we found increased odds of job strain amongst underweight [odds ratio 1.12, 95% confidence interval (CI) 1.001.25], obese class I (odds ratio 1.07, 95% CI 1.021.12) and obese classes II/III participants (odds ratio 1.14, 95% CI 1.011.28) as compared with participants of normal weight. In longitudinal analysis, both weight gain and weight loss were related to the onset of job strain during follow-up. Conclusions. In an analysis of European data, we found both weight gain and weight loss to be associated with the onset of job strain, consistent with a U-shaped cross-sectional association between job strain and BMI. These associations were relatively modest; therefore, it is unlikely that intervention to reduce job strain would be effective in combating obesity at a population level.
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