Abstract Previous studies have suggested beneficial effects of physical activity on cognition. Here, we asked in an interventional approach if physical activity performed at different intensity ...levels would differentially affect episodic memory function. Additionally, we tried to identify mechanisms mediating these changes. Sixty-two healthy elderly individuals were assessed for level of physical activity, aerobic fitness, episodic memory score, neurotrophin and catecholamine levels, and received a magnetic resonance image of the brain at baseline and after a six months intervention of medium or low-intensity physical activity or control. Increase in total physical activity was positively associated with increase in memory score over the entire cohort, without significant differences between intensity groups. It was also positively associated with increases in local gray matter volume in prefrontal and cingulate cortex, and BDNF levels (trend). In conclusion, we showed that physical activity conveys the beneficial effects on memory function independently of its intensity, possibly mediated by local gray matter volume and neurotrophic factors. Our findings may carry significant implications for prevention of cognitive decline in the elderly.
The preconditioning of major sudden stratospheric warmings (SSWs) is investigated with two long time series using reanalysis (ERA‐40) and model (MAECHAM5/MPI‐OM) data. Applying planetary wave ...analysis, we distinguish between wavenumber‐1 and wavenumber‐2 major SSWs based on the wave activity of zonal wavenumbers 1 and 2 during the prewarming phase. For this analysis an objective criterion to identify and classify the preconditioning of major SSWs is developed. Major SSWs are found to occur with a frequency of six and seven events per decade in the reanalysis and in the model, respectively, thus highlighting the ability of MAECHAM5/MPI‐OM to simulate the frequency of major SSWs realistically. However, from these events only one quarter are wavenumber‐2 major warmings, representing a low (∼0.25) wavenumber‐2 to wavenumber‐1 major SSW ratio. Composite analyses for both data sets reveal that the two warming types have different dynamics; while wavenumber‐1 major warmings are preceded only by an enhanced activity of the zonal wavenumber‐1, wavenumber‐2 events are either characterized by only the amplification of zonal wavenumber‐2 or by both zonal wavenumber‐1 and zonal wavenumber‐2, albeit at different time intervals. The role of tropospheric blocking events influencing these two categories of major SSWs is evaluated in the next step. Here, the composite analyses of both reanalysis and model data reveal that blocking events in the Euro‐Atlantic sector mostly lead to the development of wavenumber‐1 major warmings. The blocking–wavenumber‐2 major warming connection can only be statistical reliable analyzed with the model time series, demonstrating that blocking events in the Pacific region mostly precede wavenumber‐2 major SSWs.
Key Points
Analysis of the preconditioning of major SSWs by different planetary waves
Planetary wave dynamics of wavenumber‐1 and wavenumber‐2 major SSWs
Influence of tropospheric blockings on wavenumber‐1 and wavenumber‐2 major SSWs
Simulations of tropical volcanic eruptions using a general circulation model with coupled aerosol microphysics are used to assess the influence of season of eruption on the aerosol evolution and ...radiative impacts at the Earth's surface. This analysis is presented for eruptions with SO2 injection magnitudes of 17 and 700 Tg, the former consistent with estimates of the 1991 Mt. Pinatubo eruption, the later a near-"super eruption". For each eruption magnitude, simulations are performed with eruptions at 15° N, at four equally spaced times of year. Sensitivity to eruption season of aerosol optical depth (AOD), clear-sky and all-sky shortwave (SW) radiative flux is quantified by first integrating each field for four years after the eruption, then calculating for each cumulative field the absolute or percent difference between the maximum and minimum response from the four eruption seasons. Eruption season has a significant influence on AOD and clear-sky SW radiative flux anomalies for both eruption magnitudes. The sensitivity to eruption season for both fields is generally weak in the tropics, but increases in the mid- and high latitudes, reaching maximum values of ~75 %. Global mean AOD and clear-sky SW anomalies show sensitivity to eruption season on the order of 15–20 %, which results from differences in aerosol effective radius for the different eruption seasons. Smallest aerosol size and largest cumulative impact result from a January eruption for Pinatubo-magnitude eruption, and from a July eruption for the near-super eruption. In contrast to AOD and clear-sky SW anomalies, all-sky SW anomalies are found to be insensitive to season of eruption for the Pinatubo-magnitude eruption experiment, due to the reflection of solar radiation by clouds in the mid- to high latitudes. However, differences in all-sky SW anomalies between eruptions in different seasons are significant for the larger eruption magnitude, and the ~15 % sensitivity to eruption season of the global mean all-sky SW anomalies is comparable to the sensitivity of global mean AOD and clear-sky SW anomalies. Our estimates of sensitivity to eruption season are larger than previously reported estimates: implications regarding volcanic AOD timeseries reconstructions and their use in climate models are discussed.
Summary
Background Because psoriatic arthritis (PsA) usually develops years after the first manifestation of skin symptoms, in many cases the initial diagnosis of PsA depends on the dermatologist.
...Objectives To investigate the prevalence and clinical pattern of PsA in a daily practice population of patients with psoriasis.
Methods Patients were enrolled in an observational prospective cross‐sectional cohort study at 48 community and academic centres. Demographic and medical parameters were recorded, including severity of skin symptoms (Psoriasis Area and Severity Index, PASI), previous and current treatments, concomitant diseases, and the impact of psoriasis on productivity and health‐related quality of life (Dermatology Life Quality Index, DLQI). Patients with joint symptoms were referred to a rheumatologist for diagnosis and to record the activity and pattern of arthritis.
Results Among 1511 patients 20·6% had PsA; in 85% of the cases PsA was newly diagnosed. Of these patients more than 95% had active arthritis and 53·0% had five or more joints affected. Polyarthritis (58·7%) was the most common manifestation pattern, followed by oligoarthritis (31·6%) and arthritis mutilans (4·9%). Distal interphalangeal involvement was present in 41·0% and dactylitis in 23·7% of the patients. Compared with patients without arthritis, patients with PsA had more severe skin symptoms (mean PASI 14·3 vs. 11·5), a lower quality of life (mean DLQI 11·6 vs. 7·7) and greater impairment of productivity parameters.
Conclusions The findings are consistent with a high prevalence of undiagnosed cases of active PsA among patients with psoriasis seen by dermatologists. As many of these patients also have significant skin symptoms, treatment strategies are required that are equally effective in the control of skin and joint symptoms of psoriasis.
Epidemiological studies reveal better cognitive function in physically active individuals. Possible mediators for this effect are neurotrophins, which are up-regulated through physical exercise and ...induce neuronal growth and synaptogenesis in the animal model. Here we cross-sectionally assessed 75 healthy older individuals for levels of physical activity, aerobic fitness, and memory encoding, as well as neurotrophin levels and cerebral gray matter volume. We found that physical activity, but not cardiovascular fitness, was associated with better memory encoding after controlling for age, sex, education, depression, alcohol consumption, and smoking. Higher levels of physical activity were associated with higher levels of the neurotrophin granulocyte colony stimulating factor (G-CSF) and increased cerebral gray matter volume in prefrontal and cingulate cortex as assessed by magnetic resonance voxel-based morphometry. While mediating factors will need to be further elucidated, these findings indicate that even low-level physical activity exerts beneficial effects on memory functions in older individuals.
Observations and simple theoretical arguments suggest that the Northern Hemisphere (NH) stratospheric polar vortex is stronger in winters following major volcanic eruptions. However, recent studies ...show that climate models forced by prescribed volcanic aerosol fields fail to reproduce this effect. We investigate the impact of volcanic aerosol forcing on stratospheric dynamics, including the strength of the NH polar vortex, in ensemble simulations with the Max Planck Institute Earth System Model. The model is forced by four different prescribed forcing sets representing the radiative properties of stratospheric aerosol following the 1991 eruption of Mt. Pinatubo: two forcing sets are based on observations, and are commonly used in climate model simulations, and two forcing sets are constructed based on coupled aerosol–climate model simulations. For all forcings, we find that simulated temperature and zonal wind anomalies in the NH high latitudes are not directly impacted by anomalous volcanic aerosol heating. Instead, high-latitude effects result from enhancements in stratospheric residual circulation, which in turn result, at least in part, from enhanced stratospheric wave activity. High-latitude effects are therefore much less robust than would be expected if they were the direct result of aerosol heating. Both observation-based forcing sets result in insignificant changes in vortex strength. For the model-based forcing sets, the vortex response is found to be sensitive to the structure of the forcing, with one forcing set leading to significant strengthening of the polar vortex in rough agreement with observation-based expectations. Differences in the dynamical response to the forcing sets imply that reproducing the polar vortex responses to past eruptions, or predicting the response to future eruptions, depends on accurate representation of the space–time structure of the volcanic aerosol forcing.
For aqueous poly(N-isopropyl acrylamide) (PNIPAM) solutions, a structural instability leads to the collapse and aggregation of the macromolecules at the temperature-induced demixing transition. The ...accompanying cooperative dehydration of the PNIPAM chains is known to play a crucial role in this phase separation. We elucidate the impact of partial dehydration of PNIPAM on the volume changes related to the phase separation of dilute to concentrated PNIPAM solutions. Quasi-elastic neutron scattering enables us to directly follow the isotropic jump diffusion behavior of the hydration water and the almost freely diffusing water. As the hydration number decreases from 8 to 2 for the demixing 25 mass % PNIPAM solution, only a partial dehydration of the PNIPAM chains occurs. Dilatation studies reveal that the transition-induced volume changes depend in a remarkable manner on the PNIPAM concentration of the solutions. The excess volume per mole of H2O molecules expelled from the solvation layers of PNIPAM during phase separation probably strongly increases from dilute to concentrated PNIPAM solutions. This finding is qualitatively related to the immense strain-softening previously observed for demixing PNIPAM solutions.
Due to developments recently termed as ‘audit,’ ‘evaluation,’ or ‘metric society,’ universities have become subject to ratings and rankings and researchers are evaluated according to standardized ...quantitative indicators such as their publication output and their personal citation scores. Yet, this development is not only based on the rise of new public management and ideas on ‘the return on public or private investment.’ It has also profited from ongoing technological developments. Due to a massive increase in digital publishing corresponding with the growing availability of related data bibliometric infrastructures for evaluating science are continuously becoming more differentiated and elaborate. They allow for new ways of using bibliometric data through various easily applicable tools. Furthermore, they also produce new quantities of data due to new possibilities in following the digital traces of scientific publications. In this article, I discuss this development as quantification 2.0. The rise of digital infrastructures for publishing, indexing, and managing scientific publications has not only made bibliometric data become a valuable source for performance assessment. It has triggered an unprecedented growth in bibliometric data production turning freely accessible data about scientific work into edited databases and producing competition for its users. The production of bibliometric data has thus become decoupled from their application. Bibliometric data have turned into a self-serving end while their providers are constantly seeking for new tools to make use of them.
Abstract
Background
Welders demonstrate a high prevalence of musculoskeletal disorders (MSDs), as indicated by high rates of illness-related absenteeism. Leisure time physical activity (LTPA) could ...be a preventive strategy. However, little is known about LTPA prevalence and its association with MSDs among welders.
Aims
The aim of this study was to analyse the prevalence of MSD and LTPA levels among welders and to identify risk factors for the main disorder of low back pain (LBP).
Methods
The following data were collected from 145 welders from 34 companies in the German steel industry: individual factors (demographics, health behaviour), job-related factors (welding process, welding hours per day, employment years, shift work, ergonomic tools) and MSD (Nordic questionnaire). LTPA (International Physical Activity Questionnaire) was calculated to determine the metabolic equivalent of task (MET) per week as an objective measure of energy expenditure. Prevalence and multivariate regression analysis were calculated to determine odds ratios (ORs).
Results
The 12-month prevalence of LBP was 71%, for neck pain 61% and for shoulder pain 55%. Forty-two per cent of the participants accumulated <600 MET/week. The multivariate regression model revealed LTPA <600 MET/week (OR 3.4, 95% CI 1.05–10.85) and neck pain in the previous 12 months (OR 5.2, 95% CI 2.02–13.56) to be significantly associated with LBP.
Conclusions
The results show a high prevalence of MSDs and thus a strong requirement for intervention. Therefore, LTPA should be prioritized and employers should encourage access to regular activity.
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