2,703 research outputs found
Comparison of the Effect of Caffeine Ingestion on Time to Exhaustion between Endurance Trained and Untrained Men
This study compared the ergogenic effects of caffeine on men who were endurance trained to those who were untrained. The study was a double-blind, placebo-controlled crossover experimental design. Ten endurance trained men (mean age 24.4 ± 2.0 yrs, weight 79.4 ± 8.5 kg, predicted VO2 max 46.3 ± 1.8 mL·kg-1·min-1) and 10 untrained men (mean age 22.8 ± 1.9 yrs, weight 88.9 ± 9.9 kg, predicted VO2 max 37.6 ± 2.7 mL·kg-1·min-1) completed two cycle ergometer trials to exhaustion at 80% of their predicted workload max 30 min after ingesting either 5 mg·kg-1 of body weight of caffeine or a placebo. Neither group displayed significant increases in time to exhaustion (Trained Group: 786.4 ± 251.5 sec for the placebo trial and 810.7 ± 209.4 sec for the caffeine trial and the Untrained Group: 514.6 ± 107.8 sec for the placebo trial and 567.3 ± 140.5 sec for the caffeine trial) after ingesting caffeine. When compared statistically between groups, the difference was not significant. When the groups were combined, the difference was caffeine and the placebo was not significant. The findings indicate that there was no ergogenic effect of caffeine on time to exhaustion in either endurance trained or untrained men
Affective instability and impulsivity predict nonsuicidal self-injury in the general population : a longitudinal analysis
Background
Impulsivity and affective instability are related traits known to be associated with nonsuicidal self-injury, although few longitudinal studies have examined this relationship. The purpose of this study was to determine if impulsivity and affective instability predict future nonsuicidal self-injury in the general population while accounting for the overlap between these traits.
Methods
Logistic regression analyses were conducted on data from 2344 participants who completed an 18-month follow-up of the 2000 British National Psychiatric Morbidity Survey. Affective instability and impulsivity were assessed at baseline with the Structured Clinical Interview for DSM-IV Axis II Personality Disorders. Nonsuicidal self-injury was assessed at baseline and follow-up during semi-structured interviews.
Results
Affective instability and impulsivity predicted the onset of nonsuicidal self-injury during the follow-up period. Affective instability, but not impulsivity, predicted the continuation of nonsuicidal self-injury during the follow-up period. Affective instability accounted for part of the relationship between impulsivity and nonsuicidal self-injury.
Conclusions
Affective instability and impulsivity are important predictors of nonsuicidal self-injury in the general population. It may be more useful to target affective instability over impulsivity for the treatment of nonsuicidal self-injury
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HHpXRF study of recent zinc and lead pollution on lava stepping stones from Pompeii: Tourist footfall, tyre dust and leaded petrol
A helium‐enabled Niton X‐ray analyser (HHpXRF) study of 296 lava stepping stones from ancient Pompeii showed that their surfaces were contaminated with superficial deposits of Zn and Pb. Recent research has shown that concentrations of these elements are highest in urban areas, where they were attributed to tyre dust and leaded petrol, respectively. The distribution of these elements on the stepping stones is represented on maps of the site. Zn pollution is most abundant in areas visited by tourists and is attributed mostly to wear from their rubber‐soled footwear. Pb pollution is attributed to the movement of onsite vehicles using leaded petrol
Image similarity metrics suitable for infrared video stabilization during active wildfire monitoring : a comparative analysis
Aerial Thermal Infrared (TIR) imagery has demonstrated tremendous potential to monitor active forest fires and acquire detailed information about fire behavior. However, aerial video is usually unstable and requires inter-frame registration before further processing. Measurement of image misalignment is an essential operation for video stabilization. Misalignment can usually be estimated through image similarity, although image similarity metrics are also sensitive to other factors such as changes in the scene and lighting conditions. Therefore, this article presents a thorough analysis of image similarity measurement techniques useful for inter-frame registration in wildfire thermal video. Image similarity metrics most commonly and successfully employed in other fields were surveyed, adapted, benchmarked and compared. We investigated their response to different camera movement components as well as recording frequency and natural variations in fire, background and ambient conditions. The study was conducted in real video from six fire experimental scenarios, ranging from laboratory tests to large-scale controlled burns. Both Global and Local Sensitivity Analyses (GSA and LSA, respectively) were performed using state-of-the-art techniques. Based on the obtained results, two different similarity metrics are proposed to satisfy two different needs. A normalized version of Mutual Information is recommended as cost function during registration, whereas 2D correlation performed the best as quality control metric after registration. These results provide a sound basis for image alignment measurement and open the door to further developments in image registration, motion estimation and video stabilization for aerial monitoring of active wildland fires
Discovery of Reflection Nebulosity Around Five Vega-like Stars
Coronagraphic optical observations of six Vega-like stars reveal reflection
nebulosities, five of which were previously unknown. The nebulosities
illuminated by HD 4881, HD 23362, HD 23680, HD 26676, and HD 49662 resemble
that of the Pleiades, indicating an interstellar origin for dust grains. The
reflection nebulosity around HD 123160 has a double-arm morphology, but no
disk-like feature is seen as close as 2.5 arcsec from the star in K-band
adaptive optics data. We demonstrate that uniform density dust clouds
surrounding HD 23362, HD 23680 and HD 123160 can account for the observed
12-100 micron spectral energy distributions. For HD 4881, HD 26676, and HD
49662 an additional emission source, such as from a circumstellar disk or
non-equilibrium grain heating, is required to fit the 12-25 micron data. These
results indicate that in some cases, particularly for Vega-like stars located
beyond the Local Bubble (>100 pc), the dust responsible for excess thermal
emission may originate from the interstellar medium rather than from a
planetary debris system.Comment: The Astrophysical Journal, in press for March, 2002 (32 pages, 13
figures
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Surfactants for heterogeneous processes in liquid or supercritical CO.sub.2
Heterogeneous polymer mixtures comprising a polymer in liquid or supercritical CO.sub.2 are stabilized by employing a poly(propylene oxide) or poly(butylene oxide) based surfactant. These surfactants are especially well suited for stabilizing heterogeneous polymer mixtures formed by micronizing techniques as well as by precipitation of a compressed fluid antisolvent applications.Board of Regents, University of Texas Syste
An Automated Method for the Detection and Extraction of HI Self-Absorption in High-Resolution 21cm Line Surveys
We describe algorithms that detect 21cm line HI self-absorption (HISA) in
large data sets and extract it for analysis. Our search method identifies HISA
as spatially and spectrally confined dark HI features that appear as negative
residuals after removing larger-scale emission components with a modified CLEAN
algorithm. Adjacent HISA volume-pixels (voxels) are grouped into features in
(l,b,v) space, and the HI brightness of voxels outside the 3-D feature
boundaries is smoothly interpolated to estimate the absorption amplitude and
the unabsorbed HI emission brightness. The reliability and completeness of our
HISA detection scheme have been tested extensively with model data. We detect
most features over a wide range of sizes, linewidths, amplitudes, and
background levels, with poor detection only where the absorption brightness
temperature amplitude is weak, the absorption scale approaches that of the
correlated noise, or the background level is too faint for HISA to be
distinguished reliably from emission gaps. False detection rates are very low
in all parts of the parameter space except at sizes and amplitudes approaching
those of noise fluctuations. Absorption measurement biases introduced by the
method are generally small and appear to arise from cases of incomplete HISA
detection. This paper is the third in a series examining HISA at high angular
resolution. A companion paper (Paper II) uses our HISA search and extraction
method to investigate the cold atomic gas distribution in the Canadian Galactic
Plane Survey.Comment: 39 pages, including 14 figure pages; to appear in June 10 ApJ, volume
626; figure quality significantly reduced for astro-ph; for full resolution,
please see http://www.ras.ucalgary.ca/~gibson/hisa/cgps1_survey
Controlled aqueous polymerization of acrylamides and acrylates and “in situ” depolymerization in the presence of dissolved CO2
Aqueous copper-mediated radical polymerization of acrylamides and acrylates in carbonated water resulted in high monomer conversions (t t > 10 min). The regenerated monomer was characterized and repolymerized following deoxygenation of the resulting solutions to reyield polymers in high conversions that exhibit low dispersities
Affective instability and impulsivity predict nonsuicidal self-injury in the general population:a longitudinal analysis
Measurement Instruments for Integration within Children and Young People Healthcare Systems and Networks: A Rapid Review of the International Literature
Introduction: Robust measures of integration are essential for assessment of the development, design and implementation of integration within healthcare systems. This review aimed to identify measurement instruments for integration within children and young people’s (CYP) healthcare systems (PROSPERO registration number CRD42021235383).Methods: We searched electronic databases (PubMED and Ovid Embase) using three main concepts: ‘(integrated care) AND (child population) AND (measurement)’, along with additional searches.Results: Fifteen studies describing 16 measurement instruments were eligible for inclusion. The majority of studies were conducted in the USA. There was a diversity of health conditions included in the studies. The most frequent type of assessment used was a questionnaire (11 identified), but interviews, patient data and healthcare records, and focus groups were also used. Integration outcomes assessed were quality of care coordination, quality of collaboration, continuity of care, completeness of care, structure of care, quality of communication, and local implementation of integrated care.Conclusion: A variety of instruments for the measurement of integration within CYP healthcare systems were identified. Further work on the standardisation of integrated care measures would be valuable; however, it is important that instruments and measures meet the needs of specific settings, populations and conditions being studied
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