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- Breznau, Nate, et al.
(författare)
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Observing many researchers using the same data and hypothesis reveals a hidden universe of uncertainty
- 2022
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 119:44
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Tidskriftsartikel (refereegranskat)abstract
- This study explores how researchers analytical choices affect the reliability of scientific findings. Most discussions of reliability problems in science focus on systematic biases. We broaden the lens to emphasize the idiosyncrasy of conscious and unconscious decisions that researchers make during data analysis. We coordinated 161 researchers in 73 research teams and observed their research decisions as they used the same data to independently test the same prominent social science hypothesis: that greater immigration reduces support for social policies among the public. In this typical case of social science research, research teams reported both widely diverging numerical findings and substantive conclusions despite identical start conditions. Researchers expertise, prior beliefs, and expectations barely predict the wide variation in research outcomes. More than 95% of the total variance in numerical results remains unexplained even after qualitative coding of all identifiable decisions in each teams workflow. This reveals a universe of uncertainty that remains hidden when considering a single study in isolation. The idiosyncratic nature of how researchers results and conclusions varied is a previously underappreciated explanation for why many scientific hypotheses remain contested. These results call for greater epistemic humility and clarity in reporting scientific findings.
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- Jacobsen, Hedin, et al.
(författare)
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Tensile Strength After Closure of Mesenteric Gaps in Laparoscopic Gastric Bypass: Three Techniques Tested in a Porcine Model.
- 2013
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Ingår i: Obesity surgery. - : Springer Science and Business Media LLC. - 1708-0428 .- 0960-8923. ; 23:3, s. 320-324
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Internal hernias occur frequently after laparoscopic gastric bypass. We have found no data on the relative strength of the various techniques available for closing these defects. The present study was performed to obtain such data to form a theoretical basis for clinical studies. METHODS: Six piglets were operated laparoscopically and four loops of small bowel created in each. These mesenteric gaps were closed over a distance of 40mm using (1) running 2-0 Ethibond® suture, (2) Endo Hernia stapler, (3) fibrin glue (Tisseel®) and (4) controls, where the mesenteric surfaces were rubbed with a sponge and approximated without further intervention. After 6weeks, the different segments of the mesentery were excised. The tensile strength was measured using continuously increased traction until the closure ruptured. The ordinary mesentery served as the control. The breaking tension and total amount of energy transferred to the tissue were registered. RESULTS: Control areas with rubbed areas developed no adhesions. Suture and staple lines contracted by 30% in length, whereas the fibrin glued lines were even shorter. Median tensile strength was greatest for the sutured lines (14,293mN) and stapled lines (10,798mN). Fibrin glued lines were significantly weaker (6,780mN, p=0.013 and p=0.026), but as strong as ordinary mesentery (4,165mN). CONCLUSIONS: If ongoing controlled randomized trials show closure to be beneficial, further studies should include staples as one of the options for the closure of mesenteric defects. The role of fibrin glue needs to be further investigated.
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- Ahrens, J., et al.
(författare)
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Results from AMANDA
- 2001
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Ingår i: Proceedings, 9th International Workshop, Venice, Italy, March 6-9, 2001. Vol. 1, 2. ; , s. 569-580
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Konferensbidrag (refereegranskat)
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- Brok, Erik, et al.
(författare)
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Polarized neutron powder diffraction studies of antiferromagnetic order in bulk and nanoparticle NiO
- 2015
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Ingår i: Physical Review B (Condensed Matter and Materials Physics). - 1098-0121. ; 91:1
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Tidskriftsartikel (refereegranskat)abstract
- In many materials it remains a challenge to reveal the nature of magnetic correlations, including antiferromagnetism and spin disorder. Revealing the spin structure in magnetic nanoparticles is further complicated by the large incoherent neutron scattering cross section from water adsorbed at the particle surfaces and by the broadening of diffraction peaks due to the finite crystallite size. Moreover, the spin structure in magnetic nanoparticles may deviate significantly from that of the corresponding bulk material because of the low-symmetry surroundings of surface atoms and the large relative surface contribution to the magnetic anisotropy. Here we explore the potential use of polarized neutron diffraction to reveal the magnetic structure in NiO bulk and nanoparticle powders by applying the XYZ-polarization analysis method. Our investigations address in particular the spin orientation in bulk NiO and platelet-shaped NiO nanoparticles with thickness from greater than 200 nm down to 2.0 nm. The advantage of the applied method is that it is able to clearly separate the structural, the magnetic, and the spin-incoherent scattering signals for all particle sizes. For platelet-shaped particles with thickness from greater than 200 nm down to 2.2 nm we find that the spin orientation deviates about 16 degrees from the primary (111) plane of the platelet-shaped particles. In the smallest particles (2.0 nm thick) we find the spins are oriented with a 30 degrees. average angle to the primary (111) plane of the particles. The results show that polarization analyzed neutron powder diffraction is a viable method to investigate magnetic order in powders of antiferromagnetic nanoparticles.
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