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James Arthur Harris

Bio: James Arthur Harris is an academic researcher from Carnegie Institution for Science. The author has contributed to research in topics: Sugar beet & Herbaceous plant. The author has an hindex of 5, co-authored 14 publications receiving 1430 citations.


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Journal ArticleDOI
TL;DR: The 2011 Compendium is an update of a system for quantifying the energy cost of adult human PA and is a living document that is moving in the direction of being 100% evidence based.
Abstract: Purpose:The Compendium of Physical Activities was developed to enhance the comparability of results across studies using self-report physical activity (PA) and is used to quantify the energy cost of a wide variety of PA. We provide the second update of the Compendium, called the 2011 Compend

4,712 citations

Journal ArticleDOI
TL;DR: The data show that this polymorphism in PER3 predicts individual differences in the sleep-loss-induced decrement in performance and that this differential susceptibility may be mediated by its effects on sleep homeostasis.

484 citations

Journal ArticleDOI
TL;DR: A review of a range of objective measures of PA based on EE or oxygen uptake including DLW, activity energy expenditure, physical activity level, and metabolic equivalent to provide information on the utility and limitations of these measures.
Abstract: The ability to assess energy expenditure (EE) and estimate physical activity (PA) in free-living individuals is extremely important in the global context of non-communicable diseases including malnutrition, overnutrition (obesity), and diabetes. It is also important to appreciate that PA and EE are different constructs with PA defined as any bodily movement that results in EE and accordingly, energy is expended as a result of PA. However, total energy expenditure, best assessed using the criterion doubly labeled water (DLW) technique, includes components in addition to physical activity energy expenditure, namely resting energy expenditure and the thermic effect of food. Given the large number of assessment techniques currently used to estimate PA in humans, it is imperative to understand the relative merits of each. The goal of this review is to provide information on the utility and limitations of a range of objective measures of PA and their relationship with EE. The measures discussed include those based on EE or oxygen uptake including DLW, activity energy expenditure, physical activity level, and metabolic equivalent; those based on heart rate monitoring and motion sensors; and because of their widespread use, selected subjective measures.

405 citations

Journal ArticleDOI
TL;DR: The present approach is the first to establish an energy expenditure-body composition link with a mechanistic model in vivo, and has the potential to greatly expand the knowledge of energy Expenditure-body size relationships in humans.
Abstract: Investigators have expressed interest in the associations between resting energy expenditure (REE) and body mass for over a century. Traditionally, descriptive models using regression analysis are ...

400 citations

Journal ArticleDOI
TL;DR: The main objective was to compare eight methods to estimate SMR and show that 12 h is insufficient but 24 h is adequate, and a list of basic recommendations for practitioners who use respirometry to measure SMR in fishes is provided.
Abstract: This review and data analysis outline how fish biologists should most reliably estimate the minimal amount of oxygen needed by a fish to support its aerobic metabolic rate (termed standard metabolic rate; SMR). By reviewing key literature, it explains the theory, terminology and challenges underlying SMR measurements in fishes, which are almost always made using respirometry (which measures oxygen uptake, ṀO2 ). Then, the practical difficulties of measuring SMR when activity of the fish is not quantitatively evaluated are comprehensively explored using 85 examples of ṀO2 data from different fishes and one crustacean, an analysis that goes well beyond any previous attempt. The main objective was to compare eight methods to estimate SMR. The methods were: average of the lowest 10 values (low10) and average of the 10% lowest ṀO2 values, after removing the five lowest ones as outliers (low10%), mean of the lowest normal distribution (MLND) and quantiles that assign from 10 to 30% of the data below SMR (q0·1 , q0·15 , q0·2 , q0·25 and q0·3 ). The eight methods yielded significantly different SMR estimates, as expected. While the differences were small when the variability was low amongst the ṀO2 values, they were important (>20%) for several cases. The degree of agreement between the methods was related to the c.v. of the observations that were classified into the lowest normal distribution, the c.v. MLND (C.V.MLND ). When this indicator was low (≤5·4), it was advantageous to use the MLND, otherwise, one of the q0·2 or q0·25 should be used. The second objective was to assess if the data recorded during the initial recovery period in the respirometer should be included or excluded, and the recommendation is to exclude them. The final objective was to determine the minimal duration of experiments aiming to estimate SMR. The results show that 12 h is insufficient but 24 h is adequate. A list of basic recommendations for practitioners who use respirometry to measure SMR in fishes is provided.

398 citations