494 research outputs found
Application of relativistic scattering theory of x rays to diffraction anomalous fine structure in Cu
We apply our recent first-principles formalism of magnetic scattering of circularly polarized x rays to a single Cu crystal. We demonstrate the ability of our formalism to interpret the crystalline environment related near-edge fine structure features in the resonant x-ray scattering spectra at the Cu K absorption edge. We find good agreement between the computed and measured diffraction anomalous fine structure features of the x-ray scattering spectra
Inferring Absorbing Organic Carbon Content from AERONET Data
Black carbon, light-absorbing organic carbon (often called brown carbon) and mineral dust are the major light-absorbing aerosols. Currently the sources and formation of brown carbon aerosol in particular are not well understood. In this study we estimated globally the amount of light absorbing organic carbon and black carbon from AERONET measurements. We find that the columnar absorbing organic carbon (brown carbon) levels in biomass burning regions of South-America and Africa are relatively high (about 15-20 magnesium per square meters during biomass burning season), while the concentrations are significantly lower in urban areas in US and Europe. However, we estimated significant absorbing organic carbon amounts from the data of megacities of newly industrialized countries, particularly in India and China, showing also clear seasonality with peak values up to 30-35 magnesium per square meters during the coldest season, likely caused by the coal and biofuel burning used for heating. We also compared our retrievals with the modeled organic carbon by global Oslo CTM for several sites. Model values are higher in biomass burning regions than AERONET-based retrievals, while opposite is true in urban areas in India and China
Self-reported health problems and obesity predict sickness absence during a 12-month follow-up : a prospective cohort study in 21 608 employees from different industries
Objectives To study whether self-reported health problems predict sickness absence (SA) from work in employees from different industries. Methods The results of a health risk appraisal (HRA) were combined with archival data of SA of 21 608 employees (59% female, 56% clerical). Exposure variables were self-reported health problems, labelled as ' work disability (WD) risk factors' in the HRA, presence of problems with occupational well-being and obesity. Age, socioeconomic grading and the number of SA days 12 months before the survey were treated as confounders. The outcome measure was accumulated SA days during 12-month follow-up. Data were analysed separately for males and females. A Hurdle model with negative binomial response was used to analyse zero-inflated count data of SA. Results The HRA results predicted the number of accumulated SA days during the 12-month follow-up, regardless of occupational group and gender. The ratio of means of SA days varied between 2.7 and 4.0 among those with ' WD risk factors' and the reference category with no findings, depending on gender and occupational group. The lower limit of the 95% CI was at the lowest 2.0. In the Hurdle model, ' WD risk factors', SA days prior to the HRA and obesity were additive predictors for SA and/or the accumulated SA days in all occupational groups. Conclusion Self-reported health problems and obesity predict a higher total count of SA days in an additive fashion. These findings have implications for both management and the healthcare system in the prevention of WD. © Author(s) (or their employer(s)) 2019. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.Peer reviewe
Seasonal cycle and source analyses of aerosol optical properties in a semi-urban environment at Puijo station in Eastern Finland
We introduce a four-year (in 2006–2010) continuous data set of aerosol optical properties at Puijo in Kuopio, Finland. We study the annual and diurnal variation of the aerosol scattering and absorption coefficients, hemispheric backscattering fraction, scattering Ångström exponent, and single scattering albedo, whose median values over this period were 7.2 Mm<sup>−1</sup> (at 550 nm), 1.0 Mm<sup>−1</sup> (at 637 nm), 0.15, 1.93 (between 450 and 550 nm), and 0.85, respectively. The scattering coefficient peaked in the spring and autumn, being 2–4 times those in the summer and winter. An exception was the summer of 2010, when the scattering coefficient was elevated to ~300 Mm<sup>−1</sup> by plumes from forest fires in Russia. The absorption coefficient peaked in the winter when soot-containing particles derived from biomass burning were present. The higher relative absorption coefficients resulted in lower single scattering albedo in winter. The optical properties varied also with wind direction and time of the day, indicating the effect of the local pollutant sources and the age of the particles. Peak values in the single scattering albedo were observed when the wind blew from a paper mill and from the sector without local pollutant sources. These observations were linked, respectively, to the sulphate-rich aerosol from the paper mill and the oxygenated organics in the aged aerosol, which both are known to increase the scattering characteristics of aerosols. Decreases in the single scattering albedo in the morning and afternoon, distinct in the summertime, were linked to the increased traffic density at these hours. The scattering and absorption coefficients of residential and long-range transported aerosol (two separate cloud events) were found to be decreased by clouds. The effect was stronger for the scattering than absorption, indicating preferential activation of the more hygroscopic aerosol with higher scattering characteristics
Relativistic theory of magnetic scattering of x rays: Application to ferromagnetic iron
We present a detailed description of a first-principles formalism for magnetic scattering of circularly polar- ized x rays from solids in the framework of the fully relativistic spin-polarized multiple-scattering theory. The scattering amplitudes are calculated using a standard time-dependent perturbation theory to second order in the electron-photon interaction vertex. Particular attention is paid to understanding the relative importance of the positive- and negative-energy solutions of the Dirac equation to the scattering amplitude. The advantage of the present theory as compared with other recent works on magnetic x-ray scattering is that, being fully relativistic, spin-orbit coupling and spin-polarization effects are treated on an equal footing. Second, the electron Green’s function expressed in terms of the path operators in the multiple-scattering theory allows us to include the contribution of the crystalline environment to the scattering amplitude. To illustrate the use of the method we have done calculations on the anomalous magnetic scattering at the K , L_II , and L_III absorption edges of ferromagnetic iron
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Effect of Inhaled Xenon on Cerebral White Matter Damage in Comatose Survivors of Out-of-Hospital Cardiac Arrest: A Randomized Clinical Trial
IMPORTANCE: Evidence from preclinical models indicates that xenon gas can prevent the development of cerebral damage after acute global hypoxic-ischemic brain injury but, thus far, these putative neuroprotective properties have not been reported in human studies. OBJECTIVE: To determine the effect of inhaled xenon on ischemic white matter damage assessed with magnetic resonance imaging (MRI). DESIGN, SETTING, AND PARTICIPANTS: A randomized single-blind phase 2 clinical drug trial conducted between August 2009 and March 2015 at 2 multipurpose intensive care units in Finland. One hundred ten comatose patients (aged 24-76 years) who had experienced out-of-hospital cardiac arrest were randomized. INTERVENTIONS: Patients were randomly assigned to receive either inhaled xenon combined with hypothermia (33°C) for 24 hours (n = 55 in the xenon group) or hypothermia treatment alone (n = 55 in the control group). MAIN OUTCOMES AND MEASURES: The primary end point was cerebral white matter damage as evaluated by fractional anisotropy from diffusion tensor MRI scheduled to be performed between 36 and 52 hours after cardiac arrest. Secondary end points included neurological outcome assessed using the modified Rankin Scale (score 0 [no symptoms] through 6 [death]) and mortality at 6 months. RESULTS: Among the 110 randomized patients (mean age, 61.5 years; 80 men [72.7%]), all completed the study. There were MRI data from 97 patients (88.2%) a median of 53 hours (interquartile range [IQR], 47-64 hours) after cardiac arrest. The mean global fractional anisotropy values were 0.433 (SD, 0.028) in the xenon group and 0.419 (SD, 0.033) in the control group. The age-, sex-, and site-adjusted mean global fractional anisotropy value was 3.8% higher (95% CI, 1.1%-6.4%) in the xenon group (adjusted mean difference, 0.016 [95% CI, 0.005-0.027], P = .006). At 6 months, 75 patients (68.2%) were alive. Secondary end points at 6 months did not reveal statistically significant differences between the groups. In ordinal analysis of the modified Rankin Scale, the median (IQR) value was 1 (1-6) in the xenon group and 1 (0-6) in the control group (median difference, 0 [95% CI, 0-0]; P = .68). The 6-month mortality rate was 27.3% (15/55) in the xenon group and 34.5% (19/55) in the control group (adjusted hazard ratio, 0.49 [95% CI, 0.23-1.01]; P = .053). CONCLUSIONS AND RELEVANCE: Among comatose survivors of out-of-hospital cardiac arrest, inhaled xenon combined with hypothermia compared with hypothermia alone resulted in less white matter damage as measured by fractional anisotropy of diffusion tensor MRI. However, there was no statistically significant difference in neurological outcomes or mortality at 6 months. These preliminary findings require further evaluation in an adequately powered clinical trial designed to assess clinical outcomes associated with inhaled xenon among survivors of out-of-hospital cardiac arrest. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00879892
Quality of life and late-effects among childhood brain tumor survivors: a mixed method analysis
BackgroundReports on the quality of life (QOL) of childhood brain tumor (BT) survivors have been inconsistent. As cognitive limitations may restrict their participation in questionnaire-based studies, our aim was to evaluate in depth the QOL with a mixed-method analysis. MethodsThe 5-year survivors of childhood BTs born in 1975-2000 and alive in 2010 were identified via the Finnish Cancer Registry and treating clinics. Twenty-one survivors (32%) participated in a mixed-method analysis including 15D (a general health-related QOL questionnaire), the Beck Depression Inventory, and a qualitative semi-structured interview. ResultsBased on the 15D-questionnaire, the BT survivors had an impaired health-related QOL in several dimensions such as speech and usual activities. On the other hand, no difference was found in other dimensions such as distress or vitality. A majority (95%) of the survivors showed no increased risk for depression. The qualitative interview revealed that the most important aspects affecting the QOL of the survivors were positive mental growth, negative conceptions concerning illness, living one day at a time, age at diagnosis, time since diagnosis, social relationships, learning disabilities and limitations in vocational opportunities, limitations in independent life, and changed understanding of the term health'. ConclusionsChildhood BT survivors have heterogeneous attitudes on QOL. The survivors assess social aspects to be more important than functionality for their QOL. Social concerns should actively be brought up to offer support for those with significant social difficulties. Interventions for social difficulties should be more actively developed. Copyright (c) 2015 John Wiley & Sons, Ltd.</p
The effect of an active video game intervention on physical activity, motor performance, and fatigue in children with cancer: a randomized controlled trial
ObjectiveTo evaluate the effect of active video games in promoting physical activity and motor performance, and reducing fatigue in children with cancer. A randomized controlled trial was conducted. The intervention included playing Nintendo Wii™Fit (Nintendo Co., Ltd., Kyoto, Japan) for 30 min/day for 8 weeks. Physical activity was estimated with accelerometers, physical activity diaries and questionnaires. Movement-ABC2 and PedsQL™ were used to examine motor performance and fatigue. Intervention experiences and fidelity were examined with an interview.ResultsParticipants (n = 36 children with cancer, 3–16 years-old) were randomly assigned to the intervention and control groups. The median [min–max] accelerometer counts/h (500 [131–1130] vs 385 [116–1012], p = 0.63) and physical activity min/day (34 [0–150] vs 23 [0–260], p = 0.95) did not differ between the groups. Change between the pre-test and post-test regarding motor performance and fatigue was similar in both groups (motor performance p = 0.77; fatigue p = 1.00). Participants experienced playing active video games meaningful, but the intervention was not followed completely as instructed. Overall, the physical activity levels were low and one fourth of the children had or were at risk of having movement difficulties.</p
Motor Performance in Children Diagnosed with Cancer: A Longitudinal Observational Study
Children with cancer are dealing with different side and long-term
effects caused by cancer and its treatments, like vinca-alkaloids, which
may have negative effects on motor performance. However, the affected
areas of motor performance (aiming and catching, balance, manual
dexterity) and the differences in these areas between boys and girls and
diagnoses are not frequently reported in a longitudinal design.
Therefore, the aim of this study was to investigate how motor
performance changes over the course of cancer treatment. The study was
conducted with 3-to 16-year-old children with cancer (N = 36) in
2013-2017. The five assessment points were 0, 2, 6, 12 and 30 months
from diagnosis. Movement-ABC2 was used to assess motor performance. We
found that aiming and catching skills decreased significantly during the
follow-up (p p p p p p
< 0.05, respectively). Individual monitoring of motor performance
with standardized tests and physical activity/exercise programs during
and after treatment are needed.
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