431 research outputs found
Magnetic structures of the lithium orthophosphates and the study of the Bragg glass phase of vortex matter
Effects of ground movements on realistic guide models for the European Spallation Source
We model the effect of ground movement, based on empirical experience, on the
transport properties of long neutron guides by ray-tracing simulations. Our
results reproduce the large losses found by an earlier study for a simple
model, while for a more realistic engineering model of guide mounting, we find
the losses to be significantly smaller than earlier predicted. A detailed study
of the guide for the cold neutron spectrometer BIFROST at the European
Spallation Source shows that the loss is 7.0(5) % for wavelengths of 2.3-4.0
{\AA}; the typical operational wavelength range of the instrument. This amount
of loss does not call for mitigation by overillumination as suggested in the
previous work. Our work serves to quantify the robustness of the transport
properties of long neutron guides, in construction or planning at neutron
facilities worldwide.Comment: 8 pages, 12 figure
Gains from the upgrade of the cold neutron triple-axis spectrometer FLEXX at the BER-II reactor
The upgrade of the cold neutron triple-axis spectrometer FLEXX is described.
We discuss the characterisation of the gains from the new primary spectrometer,
including a larger guide and double focussing monochromator, and present
measurements of the energy and momentum resolution and of the neutron flux of
the instrument. We found an order of magnitude gain in intensity (at the cost
of coarser momentum resolution), and that the incoherent elastic energy widths
are measurably narrower than before the upgrade. The much improved count rate
should allow the use of smaller single crystals samples and thus enable the
upgraded FLEXX spectrometer to continue making leading edge measurements.Comment: 8 pages, 7 figures, 5 table
In utero exposure to glucocorticoids and risk of anxiety and depression in childhood or adolescence
Glucocorticoid use is prevalent in pregnant women, but whether in utero exposure impacts mental health in the offspring has not been fully explored. The aim of this study was to investigate if in utero exposure to synthetic glucocorticoids increases the risk of anxiety and depression in childhood or adolescence. The study was conducted as a nationwide cohort study, including negative control exposure analyses and a sibling design to optimize control of confounding. The study population comprised 1,275,909 children born in 1996–2015 in Denmark (median follow-up of 13 years). Exposure was divided into systemic and local glucocorticoid exposure, levels of cumulative dose, generic type and according to trimester of exposure. The comparison cohort was children without exposure born to maternal never-users. Negative control exposures included children without glucocorticoid exposure born to: maternal users of non-steroidal anti-inflammatory drugs or immunotherapy during pregnancy, maternal former users of systemic glucocorticoids, maternal users of systemic glucocorticoids in the postnatal period, and fathers who were prescribed glucocorticoids. The sibling design compared siblings with and without exposure. 9307 (0.7%) children were exposed to systemic glucocorticoids and 116,389 (9.1%) children were exposed to local glucocorticoids. High-dose systemic glucocorticoids (≥500 mg prednisolone equivalents) increased the risk of anxiety compared to the comparison cohort [aIRR 1.79 (95% CI: 1.36–2.37), cumulative risk 16% vs. 7.8% by age 20]. A similar result was found for depression [aIRR 1.45 (95% CI: 0.80–2.63), cumulative risk 3.6% vs. 2.6% by age 20]. The association with anxiety was consistent in the sibling design [aIRR 1.83 (95% CI: 1.03–3.66), exposed siblings (≥ 500 mg) vs. unexposed]. Sex did not modify the associations. Negative control exposure analyses indicated robustness towards confounding from genetics and family environment. No association was found with low doses of systemic exposure or local use. In conclusion, potential adverse mental health effects of in utero exposure to high-dose glucocorticoids merit clinical attention
Prenatal exposure to glucocorticoids and the prevalence of overweight or obesity in childhood
Objective: Prenatal exposure to excess cortisol can affect postnatal metabolic health by epigenetic mechanisms. We aimed to investigate if prenatal exposure to pharmacological glucocorticoids increases the risk of overweight/obesity in childhood. Design: A nationwide population registry-based cohort study. Methods: We identified 383 877 children born in Denmark (2007-2012), who underwent routine anthropometric evaluation at 5-8 years of age. Prenatal exposure to glucocorticoids was divided into systemic and topical glucocorticoids, cumulative systemic dose, and use by trimester. The comparison cohort included children without exposure, born to maternal never-users. Negative control exposures were used to investigate confounding from an underlying disease or unmeasured characteristics. Such exposures included children without glucocorticoid exposure born to maternal users of non-steroidal anti-inflammatory drugs or immunotherapy during pregnancy, maternal former users of glucocorticoids, or paternal users of glucocorticoids during the pregnancy of their partner. We estimated sex-stratified adjusted prevalence ratios (aPR) of overweight/obesity at 5-8 years of age, as epigenetic modifications have shown to be sex-specific. Results: In the study, 21 246 (11%) boys and 27 851 (15%) girls were overweight/obese at 5-8 years of age. Overall, neither systemic nor topical glucocorticoids were associated with overweight/obesity. In boys, high-dose systemic glucocorticoids was associated with higher prevalence of overweight/obesity vs the comparison cohort (aPR: 1.41 (95% CI: 1.07-1.86), prevalence: 16% vs 11%). Negative control exposures indicated robustness to confounding. Conclusion: Overweight/obesity might be an adverse effect of prenatal exposure to high-dose systemic glucocorticoids in boys. We found no association for neither prenatal exposure to lower doses of systemic nor topical glucocorticoids. These results merit clinical attention
Evaluation of the potential use of risk-based sampling to surveillance of antibacterial residues in Danish pork
Consumers consider presence of chemical substances in food products as undesirable. In Denmark, more than 20,000 samples are analysed each year for presence of antibacterial residues in Danish slaughter pigs, and these surveillance data indicate that the true antibacterial residue prevalence in Danish slaughter pigs is negligible. The question has been raised whether it would be possible to improve the cost-effectiveness of the surveillance programme. This was addressed in this study
Assisted ventilation in COPD:association between previous hospitalizations and mortality
BACKGROUND: In general, previous studies have shown an association between prior exacerbations and mortality in COPD, but this association has not been demonstrated in the subpopulation of patients in need of assisted ventilation. We examined whether previous hospitalizations were independently associated with mortality among patients with COPD ventilated for the first time. PATIENTS AND METHODS: In the Danish National Patient Registry, we established a cohort of patients with COPD ventilated for the first time from 2003 to 2011 and previously medicated for obstructive airway diseases. We assessed the number of hospitalizations for COPD in the preceding year, age, sex, comorbidity, mode of ventilation, survival to discharge, and days to death beyond discharge. RESULTS: The cohort consisted of 6,656 patients of whom 66% had not been hospitalized for COPD in the previous year, 18% once, 8% twice, and 9% thrice or more. In-hospital mortality was 45%, and of the patients alive at discharge, 11% died within a month and 39% within a year. In multivariate models, adjusted for age, sex, mode of ventilation, and comorbidity, odds ratios for in-hospital death were 1.26 (95% confidence interval [CI]: 1.11–1.44), 1.43 (95% CI: 1.19–1.72), and 1.56 (95% CI: 1.30–1.87) with one, two, and three or more hospitalizations, respectively. Hazard ratios for death after discharge from hospital were 1.32 (95% CI: 1.19–1.46), 1.76 (95% CI: 1.52–2.02), and 2.07 (95% CI: 1.80–2.38) with one, two, and three or more hospitalizations, respectively. CONCLUSION: Preceding hospitalizations for COPD are associated with in-hospital mortality and after discharge in the subpopulation of patients with COPD with acute exacerbation treated with assisted ventilation for the first time
The RECORD reporting guidelines: meeting the methodological and ethical demands of transparency in research using routinely-collected health data.
Routinely-collected health data (RCD) are now used for a wide range of studies, including observational studies, comparative effectiveness research, diagnostics, studies of adverse effects, and predictive analytics. At the same time, limitations inherent in using data collected without specific a priori research questions are increasingly recognized. There is also a growing awareness of the suboptimal quality of reports presenting research based on RCD. This has created a perfect storm of increased interest and use of RCD for research, together with inadequate reporting of the strengths and weaknesses of these data resources. The REporting of studies Conducted using Observational Routinely-collected Data (RECORD) statement was developed to address these limitations and to help researchers using RCD to meet their ethical obligations of complete and accurate reporting, as well as improve the utility of research conducted using RCD. The RECORD statement has been endorsed by more than 15 journals, including Clinical Epidemiology. This journal now recommends that authors submit the RECORD checklist together with any manuscript reporting on research using RCD
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