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| 2. |
- Botvinik-Nezer, Rotem, et al.
(författare)
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Variability in the analysis of a single neuroimaging dataset by many teams
- 2020
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 582, s. 84-88
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Tidskriftsartikel (refereegranskat)abstract
- Data analysis workflows in many scientific domains have become increasingly complex and flexible. Here we assess the effect of this flexibility on the results of functional magnetic resonance imaging by asking 70 independent teams to analyse the same dataset, testing the same 9 ex-ante hypotheses(1). The flexibility of analytical approaches is exemplified by the fact that no two teams chose identical workflows to analyse the data. This flexibility resulted in sizeable variation in the results of hypothesis tests, even for teams whose statistical maps were highly correlated at intermediate stages of the analysis pipeline. Variation in reported results was related to several aspects of analysis methodology. Notably, a meta-analytical approach that aggregated information across teams yielded a significant consensus in activated regions. Furthermore, prediction markets of researchers in the field revealed an overestimation of the likelihood of significant findings, even by researchers with direct knowledge of the dataset(2-5). Our findings show that analytical flexibility can have substantial effects on scientific conclusions, and identify factors that may be related to variability in the analysis of functional magnetic resonance imaging. The results emphasize the importance of validating and sharing complex analysis workflows, and demonstrate the need for performing and reporting multiple analyses of the same data. Potential approaches that could be used to mitigate issues related to analytical variability are discussed. The results obtained by seventy different teams analysing the same functional magnetic resonance imaging dataset show substantial variation, highlighting the influence of analytical choices and the importance of sharing workflows publicly and performing multiple analyses.
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| 3. |
- Genuneit, J., et al.
(författare)
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A multi-centre study of candidate genes for wheeze and allergy : the International Study of Asthma and Allergies in Childhood Phase 2
- 2009
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Ingår i: Clinical and Experimental Allergy. - : John Wiley & Sons. - 0954-7894 .- 1365-2222. ; 39:12, s. 1875-1888
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Common polymorphisms have been identified in genes suspected to play a role in asthma. We investigated their associations with wheeze and allergy in a case-control sample from Phase 2 of the International Study of Asthma and Allergies in Childhood.METHODS: We compared 1105 wheezing and 3137 non-wheezing children aged 8-12 years from 17 study centres in 13 countries. Genotyping of 55 candidate single nucleotide polymorphisms (SNPs) in 14 genes was performed using the Sequenom System. Logistic regression models were fitted separately for each centre and each SNP. A combined per allele odds ratio and measures of heterogeneity between centres were derived by random effects meta-analysis.RESULTS: Significant associations with wheeze in the past year were detected in only four genes (IL4R, TLR4, MS4A2, TLR9, P<0.05), with per allele odds ratios generally <1.3. Variants in IL4R and TLR4 were also related to allergen-specific IgE, while polymorphisms in FCER1B (MS4A2) and TLR9 were not. There were also highly significant associations (P<0.001) between SPINK5 variants and visible eczema (but not IgE levels) and between IL13 variants and total IgE. Heterogeneity of effects across centres was rare, despite differences in allele frequencies.CONCLUSIONS: Despite the biological plausibility of IgE-related mechanisms in asthma, very few of the tested candidates showed evidence of association with both wheeze and increased IgE levels. We were unable to confirm associations of the positional candidates DPP10 and PHF11 with wheeze, although our study had ample power to detect the expected associations of IL13 variants with IgE and SPINK5 variants with eczema.
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| 5. |
- Morales-Suarez-Varela, M.M., et al.
(författare)
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Occupational sun exposure and mycosis fungoides : A european multicenter caseg-control study
- 2006
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Ingår i: Journal of Occupational and Environmental Medicine. - : Ovid Technologies (Wolters Kluwer Health). - 1076-2752 .- 1536-5948. ; 48:4, s. 390-393
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: We sought to study the association between occupational sun exposure and mycosis fungoides (MF), a peripheral T-cell lymphoma. SUBJECTS and METHODS: A European multicenter case-control study including seven rare cases (one being MF) was conducted between 1995 and 1997. From the 118 accepted cases, 104 were interviewed, of which 76 were definite cases. Population controls were selected randomly from the regions of case ascertainment. Information based on occupational experiences was coded according to industry types. A job exposure matrix was created according to the expected exposure to sunlight. RESULTS: Once exposures to aromatic halogenated hydrocarbons were eliminated (odds ratio = 2.3, 95% confidence interval = 0.9-6.2), a high MF risk was associated with exposures to solar radiation. CONCLUSION: It would appear that workers exposed to sunlight have a higher risk of MF. However, this factor is not the only one involved. Copyright © 2006 by American College of Occupational and Environmental Medicine.
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| 6. |
- Morales-Suarez-Varela, M.M., et al.
(författare)
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Occupational exposures and Mycosis Fungoides. A European multicentre case-control study (Europe)
- 2005
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Ingår i: Cancer Causes and Control. - : Springer Science and Business Media LLC. - 0957-5243 .- 1573-7225. ; 16:10, s. 1253-1259
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Mycosis Fungoides (MF) is a rare disease with an occurrence indicating that occupational exposures may play a role. To estimate the association between MF and occupational exposures as measured by means of an job-exposure matrix (JEM). Methods: A European multicenter case-control study was conducted from 1995 to 1997 and included seven rare cancers, one of which was MF. Patients between 35 and 69 years of age, diagnosed with MF (n = 140), were recruited and the diagnoses were checked by a reference pathologist who classified 83 cases as definite, 35 cases as possible and 22 cases as not accepted. Among the 118 accepted cases, 104 cases were interviewed, of which 76 were definite cases. We selected population controls and colon cancer controls to serve all seven case groups. Altogether 833 colon cancer controls and 2071 population controls were interviewed. Based on the reported occupational experiences, a team of industrial hygiene specialists identified five potential exposures and developed an JEM. This JEM was used to estimate the odds ratios (OR) for MF as a function of these exposures. The JEM included aromatic and/or halogenated hydrocarbons (AAHs), chrome (VI) and its salts, electromagnetic radiations, silica and pesticides. Results: Exposures to AHHs (OR 6.3, C.I 2.4-16.7 for male) were associated with a high MF risk. Conclusions: The study supports the hypothesis that some MFs have an occupational etiology but only a small fraction of exposed workers are apparently susceptible since the disease is so rare. © Springer 2005.
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| 7. |
- Ortega-Ferrusola, C., et al.
(författare)
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Identification of Sperm Subpopulations in Stallion Ejaculates: Changes after Cryopreservation and Comparison with Traditional Statistics
- 2009
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Ingår i: Reproduction in domestic animals. - : Wiley-Blackwell. - 0936-6768 .- 1439-0531. ; 44:3, s. 419-423
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Tidskriftsartikel (refereegranskat)abstract
- In an attempt to improve the information obtained after computer-assisted sperm analysis (CASA), data from five stallions (three ejaculates from each) were analysed before (fresh, extended semen) and after cryopreservation using traditional statistics as well as a cluster analysis. The data matrix consisted of 13 987 observations of individual spermatozoa for fresh, extended semen, and 8305 for frozen-thawed samples. As expected, freezing and thawing resulted in a marked decrease of CASA-derived variables of sperm kinematics. All sperm velocities were significantly lower in frozen-thawed samples than in samples before cooling. Using sperm velocities, six sperm subpopulations were identified in fresh semen (S1-S6). As such, subpopulations S1 and S2 were characterized by low sperm velocities, subpopulations S3 and S4 corresponded to spermatozoa depicting medium speed values, and finally, subpopulations S5 and S6 were those depicting the highest velocities. After freezing and thawing, four sperm subpopulations were identified, listed as nr FT1 to FT4. While subpopulations FT1-FT3 were characterized by low sperm velocities, and thus corresponded speed-wise to those listed as S1-S4 for fresh, extended semen, the one called number FT4 in frozen semen was characterized by high velocities, of the same range as that of the subpopulations S5 and S6 for fresh spermatozoa. The sperm subpopulation structure varied among stallions, but the cluster analysis hereby assayed was able to provide valuable information about the freezability of the samples that the customary statistics did not reveal.
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| 8. |
- Schramm, Isabella C., et al.
(författare)
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Effects of nitrogen vacancies on phase stability and mechanical properties of arc deposited (Ti0.52Al0.48)Ny (y<1) coatings
- 2017
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Ingår i: Surface & Coatings Technology. - : Elsevier. - 0257-8972 .- 1879-3347. ; 330:Supplement C, s. 77-86
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Tidskriftsartikel (refereegranskat)abstract
- Nitrogen sub-stoichiometric (Ti0.52Al0.48)Ny (0.92 ≥ y ≥ 0.46) coatings were grown in a mixed Ar/N2 atmosphere by cathodic arc deposition on cemented carbide (WC/Co-based) substrates. The coatings present a columnar structure with decreasing column widths from 250 to 60nm, due to a corresponding reduced N content, accompanied by changes in preferred orientation from 200 to 111 to 220. Among these, coatings prepared with 0.92≥y≥0.75 exhibit spinodal decomposition and consequently age hardening at elevated temperatures. A reduced N content upshifts the hardness maximum by >300 °C. For these samples, the high temperature treatment resulted in interdiffusion of substrate elements, Co and C, mainly along column boundaries. Nevertheless, no detrimental effect in the hardness could be correlated. Conversely, a low N content sample (y=0.46) presents significant lattice diffusion of substrate elements Co, C, W, and Ta in the coating. In this case, the substrate elements are present throughout the coating, forming additional phases such as c-Ti(C,N), c-Co(Al,Ti,W), and c-(Ti,W,Ta)(C,N), with an observed increased hardness from 16 to 25GPa. We suggest that the substitution of nitrogen by carbon and the solution of W and Ta in c-TiN are responsible for the observed hardening. Our investigation shows the potential of sub-stoichiometric (Ti1-xAlx)Ny coatings for high temperature applications such as cutting tools and puts forth corresponding criteria for N content selection.
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| 9. |
- van der Heijde, Nicky, et al.
(författare)
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Use and outcome of minimally invasive pancreatic surgery in the European E-MIPS registry
- 2023
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Ingår i: HPB. - : ELSEVIER SCI LTD. - 1365-182X .- 1477-2574. ; 25:4, s. 400-408
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Tidskriftsartikel (refereegranskat)abstract
- Background: The European registry for minimally invasive pancreatic surgery (E-MIPS) collects data on laparoscopic and robotic MIPS in low-and high-volume centers across Europe.Methods: Analysis of the first year (2019) of the E-MIPS registry, including minimally invasive distal pancreatectomy (MIDP) and minimally invasive pancreatoduodenectomy (MIPD). Primary outcome was 90-day mortality.Results: Overall, 959 patients from 54 centers in 15 countries were included, 558 patients underwent MIDP and 401 patients MIPD. Median volume of MIDP was 10 (7-20) and 9 (2-20) for MIPD. Median use of MIDP was 56.0% (IQR 39.0-77.3%) and median use of MIPD 27.7% (IQR 9.7-45.3%). MIDP was mostly performed laparoscopic (401/558, 71.9%) and MIPD mostly robotic (234/401, 58.3%). MIPD was performed in 50/54 (89.3%) centers, of which 15/50 (30.0%) performed >= 20 MIPD annually. This was 30/ 54 (55.6%) centers and 13/30 (43%) centers for MIPD respectively. Conversion rate was 10.9% for MIDP and 8.4% for MIPD. Overall 90 day mortality was 1.1% (n = 6) for MIDP and 3.7% (n = 15) for MIPD.Conclusion: Within the E-MIPS registry, MIDP is performed in about half of all patients, mostly using laparoscopy. MIPD is performed in about a quarter of patients, slightly more often using the robotic approach. A minority of centers met the Miami guideline volume criteria for MIPD.
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