1,581 research outputs found
Severity of traumatic brain injury correlates with long-term cardiovascular autonomic dysfunction
After traumatic brain injury (TBI), central autonomic dysfunction might contribute to long-term increased mortality rates. Central autonomic dysfunction might depend on initial trauma severity. This study was performed to evaluate differences in autonomic modulation at rest and upon standing between patients with a history of mild TBI (post-mild-TBI patients), moderate or severe TBI (post-moderate–severe-TBI patients), and healthy controls. In 20 post-mild-TBI patients (6–78 months after TBI), age-matched 20 post-moderate–severe-TBI patients (6–94 months after TBI) and 20 controls, we monitored respiration, RR intervals (RRI) and systolic blood pressure (BPsys) at supine rest and upon standing. We determined mainly sympathetic low (LF) and parasympathetic high (HF) frequency powers of RRI fluctuations, sympathetically mediated LF-BPsys powers, LF/HF-RRI ratios, normalized (nu) LF-RRI and HF-RRI powers, and compared data between groups, at rest and upon standing (ANOVA with post hoc testing). We correlated autonomic parameters with initial Glasgow Coma Scale (GCS) scores (Spearman test; significance: p < 0.05). Supine BPsys and LFnu-RRI powers were higher while HFnu-RRI powers were lower in post-moderate–severe-TBI patients than post-mild-TBI patients and controls. LFnu-RRI powers were higher and HFnu-RRI powers were lower in post-mild-TBI patients than controls. Upon standing, only post-mild-TBI patients and controls increased LF-BPsys powers and BPsys and decreased HF-RRI powers. GCS scores correlated positively with LFnu-RRI powers, LF/HF-RRI ratios, and inversely with HFnu-RRI powers, at standing position. More than 6 months after TBI, there is autonomic dysfunction at rest and upon standing which is more pronounced after moderate–severe than mild TBI and in part correlates with initial trauma severity
Marital Status, Partnership and Health Behaviour: Findings from the German Ageing Survey (DEAS)
Numerous empirical studies have confirmed that married people have a lower risk of morbidity and mortality than unmarried people. However, there is relatively little existing research on the impact of marital status and partnerships on the health behaviour of elderly people in Europe. This study examines the association between partnership status and health-related behaviour among the German population in the second half of life (aged 40-85). We focus on four indicators of health behaviour: smoking, physical activity, body weight, and health check-ups. The data used in the analysis come from the 2008 (n=6,205) and 2014 (n=6,002) waves of the German Ageing Survey (DEAS). We applied logistic regression models with average marginal effects (AME).The results of our analysis are in line with the findings of previous studies, which indicated that being married has a protective effect on smoking and a negative effect on body weight. Crisis effects are found to be limited primarily to smoking by recently widowed people. Our study provides new empirical insights into the extent to which being married has protective effects on the use of health care, as people who are separated, divorced, or never married are found to be less likely to have regular health check-ups compared to married people. Furthermore, our results for physical activity are contrary to previous findings for younger adults, according to which being married is associated with a lower likelihood of participating in physical activities. The results of the data analyses show that at ages 40 and older, unmarried individuals, especially those who are not in a partnership, are at higher risk of physical inactivity than their married counterparts. Our findings on marital status and partnership status therefore demonstrate that being married is strongly associated with positive health behaviours. The results may be useful for designing health programmes or prevention measures
On Retardation Effects in Space Charge Calculations Of High Current Electron Beams
Laser-plasma accelerators are expected to deliver electron bunches with high
space charge fields. Several recent publications have addressed the impact of
space charge effects on such bunches after the extraction into vacuum.
Artifacts due to the approximation of retardation effects are addressed, which
are typically either neglected or approximated. We discuss a much more
appropriate calculation for the case of laser wakefield acceleration with
negligible retardation artifacts due to the calculation performed in the mean
rest frame. This presented calculation approach also aims at a validation of
other simulation approaches
The mass and angular momentum distribution of simulated massive early-type galaxies to large radii
We study the dark and luminous mass distributions, circular velocity curves
(CVC), line-of-sight kinematics, and angular momenta for a sample of 42
cosmological zoom simulations of massive galaxies. Using a temporal smoothing
technique, we are able to reach large radii. We find that: (i)The dark matter
halo density profiles outside a few kpc follow simple power-law models, with
flat dark matter CVCs for lower-mass systems, and rising CVCs for high-mass
haloes. The projected stellar density distributions at large radii can be
fitted by Sersic functions with n>10, larger than for typical ETGs. (ii)The
massive systems have nearly flat total CVCs at large radii, while the less
massive systems have mildly decreasing CVCs. The slope of the CVC at large
radii correlates with v_circ itself. (iii)The dark matter fractions within Re
are in the range 15-30% and increase to 40-65% at 5Re. Larger and more massive
galaxies have higher dark matter fractions. (iv)The short axes of simulated
galaxies and their host dark matter haloes are well aligned and their
short-to-long axis ratios are correlated. (v)The stellar vrms(R) profiles are
slowly declining, in agreement with planetary nebulae observations in the outer
haloes of most ETGs. (vi)The line-of-sight velocity fields v show that rotation
properties at small and large radii are correlated. Most radial profiles for
the cumulative specific angular momentum parameter lambda(R) are nearly flat or
slightly rising, with values in [0.06,0.75] from 2Re to 5Re. (vii)Stellar mass,
ellipticity at 5Re, and lambda(5Re) are correlated: the more massive systems
have less angular momentum and are rounder, as for observed ETGs. (viii)More
massive galaxies with a large fraction of accreted stars have radially
anisotropic velocity distributions outside Re. Tangential anisotropy is seen
only for galaxies with high fraction of in-situ stars. (Full abstract in PDF)Comment: 17 pages, 15 figures, 2 tables, accepted by MNRA
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