1,003 research outputs found
The association of reduced lung function with blood pressure variability in African Americans: data from the Jackson Heart Study
Background
African Americans (AAs) have lower lung function, higher blood pressure variability (BPV) and increased risk for hypertension and cardiovascular disease (CVD) compared with whites. The mechanism through which reduced lung-function is associated with increased CVD risk is unclear.
Methods
We evaluated the association between percent predicted lung-function and 24-hour BPV in 1008 AAs enrolled in the Jackson Heart Study who underwent ambulatory blood pressure (BP) monitoring. Lung-function was assessed as forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and the ratio of FEV1-to-FVC during a pulmonary function test using a dry rolling sealed spirometer and grouped into gender-specific quartiles. The pairwise associations of these three lung-function measures with two measures of 24-hour BPV, (1) day-night standard deviation (SDdn) and (2) average real variability (ARV) were examined for systolic BP (SBP) and, separately, diastolic BP (DBP).
Results
SDdn of SBP was not associated with FEV1 (mean ± standard deviation from lowest-to-highest quartile: 9.5 ± 2.5, 9.4 ± 2.4, 9.1 ± 2.3, 9.3 ± 2.6; p-trend = 0.111). After age and sex adjustment, the difference in SDdn of SBP was 0.0 (95 % CI −0.4,0.4), −0.4 (95 % CI −0.8,0.1) and −0.3 (95 % CI −0.7,0.1) in the three progressively higher versus lowest quartiles of FEV1 (p-trend = 0.041). Differences in SDdn of SBP across FEV1 quartiles were not statistically significant after further multivariable adjustment. After multivariable adjustment, no association was present between FEV1 and ARV of SBP or SDdn and ARV of DBP or when evaluating the association of FVC and FEV1-to-FVC with 24-hour BPV.
Conclusion
Lung-function was not associated with increased 24-hour BPV
Trends in Prehypertension and Hypertension Risk Factors in US Adults: 1999-2012.
Prehypertension is associated with increased risk for hypertension and cardiovascular disease. Data are limited on the temporal changes in the prevalence of prehypertension and risk factors for hypertension and cardiovascular disease among US adults with prehypertension. We analyzed data from 30 958 US adults ≥20 years of age who participated in the National Health and Nutrition Examination Surveys between 1999 and 2012. Using the mean of 3 blood pressure (BP) measurements from a study examination, prehypertension was defined as systolic BP of 120 to 139 mm Hg and diastolic BP <90 mm Hg or diastolic BP of 80 to 89 mm Hg and systolic BP <140 mm Hg among participants not taking antihypertensive medication. Between 1999-2000 and 2011-2012, the percentage of US adults with prehypertension decreased from 31.2% to 28.2% (P trend=0.007). During this time period, the prevalence of several risk factors for cardiovascular disease and incident hypertension increased among US adults with prehypertension, including prediabetes (9.6% to 21.6%), diabetes mellitus (6.0% to 8.5%), overweight (33.5% to 37.3%), and obesity (30.6% to 35.2%). There was a nonstatistically significant increase in no weekly leisure-time physical activity (40.0% to 43.9%). Also, the prevalence of adhering to the Dietary Approaches to Stop Hypertension eating pattern decreased (18.4% to 11.9%). In contrast, there was a nonstatistically significant decline in current smoking (25.9% to 23.2%). In conclusion, the prevalence of prehypertension has decreased modestly since 1999-2000. Population-level approaches directed at adults with prehypertension are needed to improve risk factors to prevent hypertension and cardiovascular disease
The debris disk - terrestrial planet connection
The eccentric orbits of the known extrasolar giant planets provide evidence
that most planet-forming environments undergo violent dynamical instabilities.
Here, we numerically simulate the impact of giant planet instabilities on
planetary systems as a whole. We find that populations of inner rocky and outer
icy bodies are both shaped by the giant planet dynamics and are naturally
correlated. Strong instabilities -- those with very eccentric surviving giant
planets -- completely clear out their inner and outer regions. In contrast,
systems with stable or low-mass giant planets form terrestrial planets in their
inner regions and outer icy bodies produce dust that is observable as debris
disks at mid-infrared wavelengths. Fifteen to twenty percent of old stars are
observed to have bright debris disks (at wavelengths of ~70 microns) and we
predict that these signpost dynamically calm environments that should contain
terrestrial planets.Comment: Contribution to proceedings of IAU 276: Astrophysics of Planetary
System
Circadian preference and physical and cognitive performance in adolescence:A scoping review
Adolescence is a crucial period of development which coincides with changes in circadian rhythmicity. This may augment the impact of circadian preference on performance in this group. We aimed to scope the literature available on chronotypes and their effect on physical and mental aspects of performance in adolescents. Methods: Studies were identified by systematically searching bibliographical databases and grey literature. Results: The Morningness-Eveningness Questionnaire was the most frequently reported tool for circadian preference assessment. Academic achievement was the most prevailing outcome, with evidence suggesting that morning type adolescents tend to outperform evening types, yet the results vary depending on multiple factors. Performance in tests of intelligence and executive functions was generally better at optimal times of the day (synchrony effect). Physical performance was examined in 8 studies, with very heterogeneous outcomes. Conclusions: Although the associations between circadian preference and performance in adolescents are evident in some areas, there are many factors that may be involved in the relationship and require further investigation. This review highlights the assessment of physical performance in relation to chronotypes, the multidimensional assessment of circadian preference, and the need for longitudinal studies as priorities for further research
Duality of Quasilocal Gravitational Energy and Charges with Non-orthogonal Boundaries
We study the duality of quasilocal energy and charges with non-orthogonal
boundaries in the (2+1)-dimensional low-energy string theory. Quasilocal
quantities shown in the previous work and some new variables arisen from
considering the non-orthogonal boundaries as well are presented, and the boost
relations between those quantities are discussed. Moreover, we show that the
dual properties of quasilocal variables such as quasilocal energy density,
momentum densities, surface stress densities, dilaton pressure densities, and
Neuve-Schwarz(NS) charge density, are still valid in the moving observer's
frame.Comment: 19pages, 1figure, RevTe
Evaluation of Criteria to Detect Masked Hypertension
The prevalence of masked hypertension, out-of-clinic daytime systolic/diastolic blood pressure (SBP/DBP)≥135/85 mmHg on ambulatory blood pressure monitoring (ABPM) among adults with clinic SBP/DBP<140/90 mmHg, is high. It is unclear who should be screened for masked hypertension. We derived a clinic blood pressure (CBP) index to identify populations for masked hypertension screening. Index cut-points corresponding to 75% to 99% sensitivity and prehypertension were evaluated as ABPM testing criterion. In a derivation cohort (n=695), the index was clinic SBP+1.3*clinic DBP. In an external validation cohort (n=675), the sensitivity for masked hypertension using an index ≥190 mmHg and ≥217 mmHg and prehypertension status was 98.5%, 71.5% and 82.5%, respectively. Using NHANES data (n=11,778), we estimated that these thresholds would refer 118.6, 44.4 and 59.3 million US adults, respectively, to ABPM screening for masked hypertension. In conclusion, the CBP index provides a useful approach to identify candidates for masked hypertension screening using ABPM
Advances in Measuring the Apparent Optical Properties (AOPs) of Optically Complex Waters
This report documents new technology used to measure the apparent optical properties (AOPs) of optically complex waters. The principal objective is to be prepared for the launch of next-generation ocean color satellites with the most capable commercial off-the-shelf (COTS) instrumentation. An enhanced COTS radiometer was the starting point for designing and testing the new sensors. The follow-on steps were to apply the lessons learned towards a new in-water profiler based on a kite-shaped backplane for mounting the light sensors. The next level of sophistication involved evaluating new radiometers emerging from a development activity based on so-called microradiometers. The exploitation of microradiometers resulted in an in-water profiling system, which includes a sensor networking capability to control ancillary sensors like a shadowband or global positioning system (GPS) device. A principal advantage of microradiometers is their flexibility in producing, interconnecting, and maintaining instruments. The full problem set for collecting sea-truth data--whether in coastal waters or the open ocean-- involves other aspects of data collection that were improved for instruments measuring both AOPs and inherent optical properties (IOPs), if the uncertainty budget is to be minimized. New capabilities associated with deploying solar references were developed as well as a compact solution for recovering in-water instrument systems from small boats
Differences in night-time and daytime ambulatory blood pressure when diurnal periods are defined by self-report, fixed-times, and actigraphy: Improving the Detection of Hypertension study
To determine whether defining diurnal periods by self-report, fixed-time or actigraphy produce different estimates of nighttime and daytime ambulatory blood pressure (ABP)
Optical Sensors for Planetary Radiant Energy (OSPREy): Calibration and Validation of Current and Next-Generation NASA Missions
A principal objective of the Optical Sensors for Planetary Radiance Energy (OSPREy) activity is to establish an above-water radiometer system as a lower-cost alternative to existing in-water systems for the collection of ground-truth observations. The goal is to be able to make high-quality measurements satisfying the accuracy requirements for the vicarious calibration and algorithm validation of next-generation satellites that make ocean color and atmospheric measurements. This means the measurements will have a documented uncertainty satisfying the established performance metrics for producing climate-quality data records. The OSPREy approach is based on enhancing commercial-off-the-shelf fixed-wavelength and hyperspectral sensors to create hybridspectral instruments with an improved accuracy and spectral resolution, as well as a dynamic range permitting sea, Sun, sky, and Moon observations. Greater spectral diversity in the ultraviolet (UV) will be exploited to separate the living and nonliving components of marine ecosystems; UV bands will also be used to flag and improve atmospheric correction algorithms in the presence of absorbing aerosols. The short-wave infrared (SWIR) is expected to improve atmospheric correction, because the ocean is radiometrically blacker at these wavelengths. This report describes the development of the sensors, including unique capabilities like three-axis polarimetry; the documented uncertainty will be presented in a subsequent report
Sedentary behavior and subclinical atherosclerosis in African Americans: cross-sectional analysis of the Jackson heart study
BACKGROUND: Previous studies have reported conflicting results as to whether an association exists between sedentary time and cardiovascular disease (CVD) risk among African Americans. These studies, however, were limited by lack of consideration of sedentary behavior in leisure versus non-leisure settings. To elucidate this relation, we investigated the associations of television (TV) viewing time and occupational sitting with carotid intima-media thickness (CIMT), a subclinical atherosclerosis measure, in a community-based sample of African Americans. METHODS: We studied 3410 participants from the Jackson Heart Study, a single-site, community-based study of African Americans residing in Jackson, MS. CIMT was assessed by ultrasonography and represented mean far-wall thickness across right and left sides of the common carotid artery. TV viewing time, a measure of leisure sedentary behavior, and occupational sitting, a measure of non-leisure sedentary behavior, were assessed by questionnaire. RESULTS: In a multivariable regression model that included physical activity and CVD risk factors, longer TV viewing time (2-4 h/day and >4 h/day) was associated with greater CIMT (adjusted mean ± SE difference from referent [4 h/day; P-trend =0.001). In contrast, more frequent occupational sitting ('sometimes' and 'often/always') was associated with lower CIMT (adjusted mean ± SE difference from referent ['never/seldom']:-0.021 ± 0.009 mm for 'sometimes', and-0.018 ± 0.008 mm for 'often/always'; P-trend = 0.042). CONCLUSIONS: Longer TV viewing time was associated with greater CIMT, while occupational sitting was associated with lower CIMT. These findings suggest the role of sedentary behaviors in the pathogenesis of CVD among African Americans may vary by whether individuals engage in leisure versus non-leisure sedentary behaviors
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