Real-world walking economy: can laboratory equations predict field energy expenditure?

We addressed a practical question that remains largely unanswered after more than a century of active investigation: can equations developed in the laboratory accurately predict the energy expended under free-walking conditions in the field? Seven subjects walked a field course of 6415 meters that varied in gradient (-3.0 to +5.0%) and terrain (asphalt, grass) under unloaded (body weight only, Wb) and balanced, torso-loaded (1.30 x Wb) conditions at self-selected speeds while wearing portable calorimeter and GPS units. Portable calorimeter measures were corrected for a consistent measurement-range offset (+13.8±1.8%, mean±sd) vs. a well-validated laboratory system (Parvomedics TrueOne). Predicted energy expenditure totals (mls O2/kg) from four literature equations: ACSM, Looney, Minimum Mechanics and Pandolf, were generated using the speeds and gradients measured throughout each trial in conjunction with empirically determined terrain/treadmill factors (asphalt=1.0, grass=1.08). The mean energy expenditure total measured for the unloaded field trials (981±91 mls O2/kg) was over-predicted by +4%, +13%, +17% and +20% by the Minimum Mechanics, ACSM, Pandolf, and Looney equations, respectively (corresponding predicted totals: 1018±19, 1108±26, 1145±37, and 1176±24 mls O2/kg). The measured loaded-trial total (1310±153 mls O2/kg) was slightly under-predicted by the Minimum Mechanics equation (-2%, 1289±22 mls O2/kg) and over-predicted by the Pandolf equation (+13%, 1463±32 mls O2/kg). Computational comparisons for hypothetical trials at different constant speeds (range: 0.6-1.8 m/s) on variable-gradient loop courses revealed between-equation prediction differences from 0 to 37%. We conclude that treadmill-based predictions of free-walking field energy expenditure are equation-dependent but can be highly accurate with rigorous implementation.

The spread of breathing air from wind instruments and singers using schlieren techniques

In this article, the spread of breathing air when playing wind instruments and singing was investigated and visualized using two methods: (1) schlieren imaging with a schlieren mirror and (2) background-oriented schlieren (BOS). These methods visualize airflow by visualizing density gradients in transparent media. The playing of professional woodwind and brass instrument players, as well as professional classical trained singers, were investigated to estimate the spread distances of the breathing air. For a better comparison and consistent measurement series, a single high and a single low note as well as an extract of a musical piece were investigated. Additionally, anemometry was used to determine the velocity of the spreading breathing air and the extent to which it was still quantifiable. The results presented in this article show there is no airflow escaping from the instruments, which is transported farther than 1.2 m into the room. However, differences in the various instruments have to be considered to assess properly the spread of the breathing air. The findings discussed below help to estimate the risk of cross-infection for wind instrument players and singers and to develop efficacious safety precautions, which is essential during critical health periods such as the current COVID-19 pandemic.

The Analysis and the Measurement of Poverty: An Interval Based Composite Indicator Approach

The analysis and measurement of poverty is a crucial issue in the field of social science. Poverty is a multidimensional notion that can be measured using composite indicators relevant to synthesizing statistical indicators. Subjective choices could, however, affect these indicators. We propose interval-based composite indicators to avoid the problem, enabling us in this context to obtain robust and reliable measures. Based on a relevant conceptual model of poverty we have identified, we will consider all the various factors identified. Then, considering a different random configuration of the various factors, we will compute a different composite indicator. We can obtain a different interval for each region based on the distinct factor choices on the different assumptions for constructing the composite indicator. So we will create an interval-based composite indicator based on the results obtained by the Monte-Carlo simulation of all the different assumptions. The different intervals can be compared, and various rankings for poverty can be obtained. For their parameters, such as center, minimum, maximum, and range, the poverty interval composite indicator can be considered and compared. The results demonstrate a relevant and consistent measurement of the indicator and the shadow sector's relevant impact on the final measures.

Index for the Consistent Measurement of Spatial Heterogeneity for Large-Scale Land Cover Datasets

Recognizing land cover heterogeneity is essential for the assessment of spatial patterns to guide conservation planning. One of the top research priorities is the quantification of land cover heterogeneity using effective landscape metrics. However, due to the diversity of land cover types and their varied distribution, a consistent, larger-scale, and standardized framework for heterogeneity information extraction from this complex perspective is still lacking. Consequently, we developed a new Land Cover Complexity Index (LCCI), which is based on information-theory. The LCCI contains two foundational aspects of heterogeneity, composition and configuration, thereby capturing more comprehensive information on land cover patterns than any single metric approach. In this study, we compare the performance of the LCCI with that of other landscape metrics at two different scales, and the results show that our newly developed indicator more accurately characterizes and distinguishes different land cover patterns. LCCI provides an alternative way to measure the spatial variation of land cover distribution. Classification maps of land cover heterogeneity generated using the LCCI provide valuable insights and implications for regional conservation planning. Thus, the LCCI is shown to be a consistent indicator for the quantification of land cover heterogeneity that functions in an adaptive way by simultaneously considering both composition and configuration.

BN-invariant Sharpness Regularizes the Training Model to Better Generalization

It is arguably believed that flatter minima can generalize better. However, it has been pointed out that the usual definitions of sharpness, which consider either the maxima or the integral of loss over a delta ball of parameters around minima, cannot give consistent measurement for scale invariant neural networks, e.g., networks with batch normalization layer. In this paper, we first propose a measure of sharpness, BN-Sharpness, which gives consistent value for equivalent networks under BN. It achieves the property of scale invariance by connecting the integral diameter with the scale of parameter. Then we present a computation-efficient way to calculate the BN-sharpness approximately i.e., one dimensional integral along the "sharpest" direction. Furthermore, we use the BN-sharpness to regularize the training and design an algorithm to minimize the new regularized objective. Our algorithm achieves considerably better performance than vanilla SGD over various experiment settings.

Accurate Dopant and Interface Characterization in Oxidized SiC with Refined Non-Contact C-V Technique

The non-contact C-V technique has been recently gaining interest as a precise, cost and time effective metrology for wide-bandgap semiconductors. Originally focused on dopant measurement, non-contact C-V has been expanding to encompass wide-bandgap surface and interface characterization, including complex reliability issues critical for the future of power devices. In this work, we report progress achieved using a new direct method for determining the flatband voltage, VFB, and capacitance, CFB. Experimental results are presented for n-type oxidized epitaxial 4-H SiC. They demonstrate the approach and the unique self-consistent measurement producing an entire set of pertinent electrical parameters, including the interface trap density, Dit.

Toward Consistency: Updating Lactation and Breastfeeding Terminology for Population Health Research

There has, historically, been a lack of consistency in the use and definition of terms and their associated measurement in breastfeeding research. The purpose of this paper is to promote consistency through a taxonomy and lexicon for population-based breastfeeding research with the modern nursing dyad. The taxonomy organizes concepts in categories related to research on feeding human milk to infants, noting the perspective from the provider of human milk (parent or alloparent) and the receiver of human milk (child). The taxonomy includes these categories: psychology, physiology, behavior, and modality. The intensity of behaviors and modalities can be characterized qualitatively or quantitatively. Other terms are introduced or defined for the modern era and measurement standards are posed. These suggestions invite discussion and debate, in an effort to move researchers toward consistent measurement, documentation, and presentation, to build a credible evidence base for breastfeeding and practices related to the provision and consumption of human milk.

The Distance between the Pectoralis Major Tendon Insertion and the Top of the Humeral Head is a Reliable Landmark: An Anatomic Study

Purpose This study aimed to analyze the distance between the superior edge of the pectoralis major and the top of the humeral head and evaluate whether this distance is a consistent measurement. Methods Twenty-two shoulders in eleven cadavers were dissected and the attachment of the pectoralis major tendon was preserved. Two distances were recorded with the help of digital vernier caliper: the distance between the upper edge of pectoralis major and tangent to the top of humeral head (PM–T) and the distance between the superomedial tip of greater tuberosity (GT) and the upper edge of the pectoralis major tendon (PM–G; ± standard error of the means). Results The mean PM–T distance was 53.8 mm (±0.8 mm) and the mean PM–G distance was 46.8 mm (±0.9 mm). The distance between the top of humeral head and tip of the GT was 7 mm. The PM–T distance was a significant outlier in three shoulders as it inserted high on the humerus. Conclusion We can conclude that the PM–T and PM–G distances were a consistent measurement. Clinical Relevance The distance between the pectoralis major tendon and top of the humeral head was measured in this study as a reliable method that can be used intraoperatively to decide the height of the humerus prosthesis in comminuted fractures of the proximal humerus.

Binary and Nonbinary Measures of Successful Aging: Do They Yield Comparable Conclusions?

Recently, some researchers have employed nonbinary measures of successful aging. Little has been done to determine whether these newer measures yield similar findings compared to traditional binary measures. To test for differences, three measures of successful aging were constructed within five waves of the Americans’ Changing Lives data set. A number of demographic, behavioral, and psychosocial predictors were used to predict each outcome, examining whether estimates of effect sizes and statistical significance were similar across measures. Although many effect sizes were similar, conclusions regarding statistical significance were inconsistent. For instance, the binary measure downplayed income gradients, the ordinal measure found more racial disparities, and the continuous measure was most likely to detect effects for stressful life events. These differences may be due to the statistical techniques used to handle each outcome. Results imply that uneven application of operationalization approaches may complicate replication efforts, suggesting a need for consistent measurement standards.