Leisure-time physical activity sustained since midlife and preservation of cognitive function: The Atherosclerosis Risk in Communities Study

Introduction: We tested the hypotheses that higher levels of and persistence of midlife leisure-time physical activity (LTPA) are associated long-term with lower cognitive decline and less incident dementia. Methods: A total of 10,705 participants (mean age: 60 years) had LTPA (no, low, middle, or high) measured in 1987-1989 and 1993-1995. LTPA was assessed in relation to incident dementia and 14-year change in general cognitive performance. Results: Over a median follow-up of 17.4 years, 1063 dementia cases were observed. Compared with no LTPA, high LTPA in midlife was associated with lower incidence of dementia (hazard ratio [95% confidence interval], 0.71 [0.61, 0.86]) and lower declines in general cognitive performance (−0.07 standard deviation difference [−0.12 to −0.04]). These associations were stronger when measured against persistence of midlife LTPA over 6 years. Discussion: LTPA is a readily modifiable factor associated inversely with long-term dementia incidence and cognitive decline

The association of Step-based metrics and adiposity in the Hispanic community Health Study/Study of Latinos

Objective: Examine cross-sectional and longitudinal associations of accelerometer measured step volume (steps/day) and cadence with adiposity and six-year changes in adiposity in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Methods: HCHS/SOL's target population was 60% female with a mean age of 41 years. Cross-sectional (n = 12,353) and longitudinal analyses (n = 9,077) leveraged adjusted complex survey regression models to examine associations between steps/day, and cadence with weight (kg), waist circumference (cm) and body mass index (kg/m2). Effect measure modification by covariates was examined. Results: Lower steps/day and intensity was associated with higher adiposity at baseline. Compared to those in the highest quartile of steps/day those in the lowest quartile have 1.42 95% CI (1.19, 1.70) times the odds of obesity. Compared to those in the highest categories of cadence step-based metrics, those in the lowest categories had a 1.62 95% CI (1.36, 1.93), 2.12 95% CI (1.63, 2.75) and 1.41 95% CI (1.16, 1.70) odds of obesity for peak 30-minute cadence, brisk walking and faster ambulation and bouts of purposeful steps and faster ambulation, respectively. Compared to those with the highest stepping cadences, those with the slowest peak 30-minute cadence and fewest minutes in bouts of purposeful steps and faster ambulation had 0.72 95% CI (0.57, 0.89) and 0.82 95% CI (0.60, 1.14) times the odds of gaining weight, respectively. Conclusion: Inverse cross-sectional relationships were found for steps/day and cadence and adiposity. Over a six-year period, higher step intensity but not volume was associated with higher odds of gaining weight

Central arterial stiffness is associated with structural brain damage and poorer cognitive performance: The ARIC study

Background Central arterial stiffening and increased pulsatility, with consequent cerebral hypoperfusion, may result in structural brain damage and cognitive impairment. Methods and Results We analyzed a cross‐sectional sample of ARIC‐NCS(Atherosclerosis Risk in Communities–Neurocognitive Study) participants (aged 67–90 years, 60% women) with measures of cognition (n=3703) and brain magnetic resonance imaging (n=1255). Central arterial hemodynamics were assessed as carotid‐femoral pulse wave velocity and pressure pulsatility (central pulse pressure). We derived factor scores for cognitive domains. Brain magnetic resonance imaging using 3‐Tesla scanners quantified lacunar infarcts; cerebral microbleeds; and volumes of white matter hyperintensities, total brain, and the Alzheimer disease signature region. We used logistic regression, adjusted for demographics, apolipoprotein E ɛ4, heart rate, mean arterial pressure, and select cardiovascular risk factors, to estimate the odds of lacunar infarcts or cerebral microbleeds. Linear regression, additionally adjusted for intracranial volume, estimated the difference in log‐transformed volumes of white matter hyperintensities, total brain, and the Alzheimer diseasesignature region. We estimated the mean difference in cognitive factor scores across quartiles of carotid‐femoral pulse wave velocity or central pulse pressure using linear regression. Compared with participants in the lowest carotid‐femoral pulse wave velocity quartile, participants in the highest quartile of carotid‐femoral pulse wave velocity had a greater burden of white matter hyperintensities (P=0.007 for trend), smaller total brain volumes (−18.30 cm 3 ; 95% CI, −27.54 to −9.07 cm 3 ), and smaller Alzheimer disease signature region volumes (−1.48 cm 3 ; 95% CI, −2.27 to −0.68 cm 3 ). These participants also had lower scores in executive function/processing speed (β=−0.04 z score; 95% CI, −0.07 to −0.01 z score) and general cognition (β=−0.09 z score; 95% CI, −0.15 to −0.03 z score). Similar results were observed for central pulse pressure. Conclusions Central arterial hemodynamics were associated with structural brain damage and poorer cognitive performance among older adults

Spatial interpolation of the deuterium and oxygen-18 composition of global precipitation using temperature as ancillary variable

To aid our research in geographical forensic provenancing and food authentication we have developed high resolution prediction maps of the annual mean deuterium and oxygen-18 composition of modern precipitation. The maps have a spatial resolution of 10′ (∼ 20 × 20 km at the equator) and cover the global land surface excluding the Antarctic. To achieve this, the relation between various temperature related variables and the isotopic composition of modern precipitation was explored using a combination of high resolution climate maps and global isotope records from the GNIP database. This revealed that the isotopic composition of precipitation is somewhat better correlated to the temperature during the coldest – often driest – period of year than the temperatures during the warmest – often wettest – period of year (especially below 0 °C). Although the reason for this effect is not directly clear, the temperature during the coldest quarter is used as ancillary variable in simple kriging with varying local means (SKlm). In SKlm, only the residual isotope values from the regression with Tcq are kriging interpolated, which are then added to the predicted isotope map based on Tcq. Because the ancillary variable explains the bulk of the isotopic variation (R2 = 0.79–0.85), the deuterium and oxygen-18 maps mainly reflect the large scale global temperature pattern. More local isotope effects are accounted for by the interpolation of the residual values. This study furthermore shows that surface temperature better explains the global isotopic variation compared to a combination of latitude and altitude (R2 = 0.68–0.69). Yet, at very low temperatures (< − 40 °C) our maps might underestimate the true isotope signal. The new isotope maps and the maps of the 95% confidence intervals can be downloaded from www.waterisotopes.org

Tl concentration and its variation in a CsI(Tl) crystal for the CALIFA detector

© 2020 Published by Elsevier B.V. One of the factors that can contribute to the resolution of long, doped inorganic scintillators used for nuclear spectroscopy is the variation of the dopant concentration over the length the detector crystal. In this work an investigation of such potential variations in one of the CsI(Tl) scintillators used in the calorimeter, CALIFA, of the R3B experiment at FAIR, has been performed using particle induced X-ray emission. No statistically significant gradient in doping level was found along the long axis of the investigated sample crystal and the mean value of the Tl concentration was measured to be 0.0839(38)% by weight. This corresponds to a light output of 97.3−1.7 +1.3% relative to the maximum attainable light output according to previously published work. By taking the ±1σ bounds, the 3% statistical spread in the relative light output provides a good reference value of the minimum light-output non-uniformity observed for the CALIFA crystals. If the relative light output is estimated pointwise from a set of Tl concentration measurements a light-output non-uniformity of 4.6(2.4)% results. For a γ-ray energy of 662 keV the deduced variation in Tl concentration contributes with 0.48(6)% to the typical resolution of 7.74(6)% measured with a collimated source along the crystal main axis. The result is of interest for the characterization of the detector system performance and for realistic simulations of the light collection process in detector systems that are used for nuclear spectroscopy and calorimetry11sciescopu