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The Mars Atmosphere and Volatile Evolution (MAVEN) mission instrument suite includes an ultraviolet echelle spectrograph with high‐spectral resolution designed to resolve D and H Lyman‐α emissions. The high‐spectral resolution mode was previously characterized in the lab and in the cruise phase to Mars and had been calibrated using observations and models of interplanetary hydrogen Lyman‐α emissions. This work presents improved characterizations of the high‐spectral resolution mode using in‐orbit observations that allow for more robust detections of the faint D Lyman‐α emission line. Additionally, the instrument was re‐calibrated using simultaneous and comparable observations made with the Hubble Space Telescope high‐spectral resolution instrument. Comparisons to Lyman‐α observations made with the low‐resolution UV channel on the spectrometer, that had been calibrated with stars, showed consistency in the brightness values for measurements obtained at similar observational conditions. The combined upgrades to the faint‐emission fitting and new calibration techniques of the MAVEN echelle channel have resulted in an improved data‐reduction pipeline with favorable implications for the science utility of D and H Lyman‐α emissions. Plain Language Summary: The MAVEN high resolution echelle (ECH) instrument has been used to observe ultraviolet emissions from Mars. Measurements made with MAVEN/ECH were made available to the public by using a data reduction pipeline that had been developed with in‐lab and theoretical analysis to convert observations into a form that was useable by the broader scientific community. Since MAVEN's orbit insertion in 2014, the ECH detector has been better characterized with lessons learned from in‐orbit performance. These improvements produced a new data reduction pipeline that has enhanced the detection of faint D Lyman‐α emissions that are critical to interpreting water loss from the upper atmosphere of Mars. Key Points: MAVEN/ECH uses HST/STIS, the only other UV echelle instrument deployed to space, for calibration and independent verificationThe MAVEN/ECH data reduction algorithm has been upgraded to improve detection of faint D Lyman‐α emissionsThe scientific implications of this work include doubling the previous data set of D measurements available for reliable interpretation [ABSTRACT FROM AUTHOR]

The Coastal Dune Model, used to examine controls on dune development and evolution, includes negative feedback between the wind and the evolving topography that results in a scale‐invariant beach‐dune profile. While a limited number of reference profiles appear to support the Coastal Dune Model assumption of scale‐invariance, previously published studies and conceptual models suggest that the beach‐dune profile is not scale‐invariant. Using a combination of journal articles, textbooks, and remotely sensed data from Prince Edward Island, Washington state, and Texas, this short communication finds that there is no evidence for a scale‐invariant beach‐dune profile within and between field sites. Variability in the beach‐dune profile is due to site‐specific and scale‐dependent controls on the beach and the dune that are often highlighted in the conceptual models that authors use to depict the controls on sediment supply and transport from the beach to the dune. Results highlight a need to critically evaluate the assumptions and applications of models such as the Coastal Dune Model, and to explore how and when sites can be considered representative and in support of model results. Key Messages: There is no scale‐invariant beach‐dune profile as assumed in recent models.Beach‐dune profiles vary in response to site‐specific and scale‐dependent controls on sediment supply and transport.Further study is required to determine how and when sites can be considered representative. [ABSTRACT FROM AUTHOR]

The enhanced ratio of deuterium to hydrogen on Mars has been widely interpreted as indicating the loss of a large column of water into space, and the hydrogen content of the upper atmosphere is now known to be highly variable. The variation in the properties of both deuterium and hydrogen in the upper atmosphere of Mars is indicative of the dynamical processes that produce these species and propagate them to altitudes where they can escape the planet. Understanding the seasonal variability of D is key to understanding the variability of the escape rate of water from Mars. Data from a 15 month observing campaign, made by the Mars Atmosphere and Volatile Evolution Imaging Ultraviolet Spectrograph high-resolution echelle channel, are used to determine the brightness of deuterium as observed at the limb of Mars. The D emission is highly variable, with a peak in brightness just after southern summer solstice. The trends of D brightness are examined against extrinsic as well as intrinsic sources. It is found that the fluctuations in deuterium brightness in the upper atmosphere of Mars (up to 400 km), corrected for periodic solar variations, vary on timescales that are similar to those of water vapor fluctuations lower in the atmosphere (20-80 km). The observed variability in deuterium may be attributed to seasonal factors such as regional dust storm activity and subsequent circulation lower in the atmosphere. [ABSTRACT FROM AUTHOR]

Globally, boys and men are more physically active than girls and women. Despite geographical variation in physical activity participation and gender differences across types of physical activities, physical activity is frequently assessed at national scales using only select indicators. Using 2012 Canadian Community Health Survey data, we undertake a gender-based analysis using cross tabulations, chi-square tests, and binary logistic regression models to investigate whether gender differences in physical activity vary across geographical scales and physical activity types in Canada. We examine: (1) whether gender gaps in physical activity change across geographical scale (national, provincial, city); (2) if any geographical variation in gender differences varies by activity type (active leisure time, weight-training, home exercises); (3) whether age and/or income help to explain geographical variation in gender differences in physical activity; and (4) if gender, age, marital status, education, and income level predict variation in differences in physical activity at different geographical scales. Results demonstrate that both scale and activity type matter for how gender differences in physical activity are observed. By zooming in or out, or by changing the activity lens, gender gaps emerged or disappeared. We conclude that physical activity interventions need to be gender-sensitive in ways that are place-specific. L'entraînement physique au Canada : existe-t-il un écart entre les genres? Les garçons et les hommes sont généralement plus actifs que les filles et les femmes. Malgré l'existence de disparités géographiques dans la participation à l'activité physique et de différences entre les genres en fonction des types d'activité physique, des évaluations de l'activité physique prenant appui sur quelques indicateurs prédéterminés sont souvent réalisées à l'échelle nationale. Une analyse différenciée selon le genre a été effectuée à partir des données tirées de l'Enquête sur la santé dans les collectivités canadiennes de 2012 à l'aide de tableaux croisés, de tests de khi-deux et de modèles de régression logistique binaire, afin de déterminer si les différences entre les genres en matière d'activité physique varient selon les échelles géographiques et les types d'activité physique au Canada. Il s'agit de déterminer : (1) s'il existe des écarts liés au genre dans la variation de l'activité physique en fonction de l'échelle géographique (nationale, provinciale, urbaine); (2) si certaines disparités géographiques des écarts entre les genres varient en fonction du type d'activité (temps consacré aux loisirs actifs, musculation, exercices pratiqués à la maison); (3) si l'âge ou le revenu sont des facteurs qui contribuent aux disparités géographiques des écarts entre les genres; et (4) s'il est possible de prédire les effets du genre, de l'âge, de l'état civil, de la scolarité et du revenu sur la variation de l'écart de l'activité physique aux différentes échelles géographiques. Les résultats confirment que l'échelle et le type d'activité exercent une influence sur la manière de voir les écarts entre les genres en matière d'activité physique. En modifiant l'échelle d'observation ou la forme que prend l'activité physique, des écarts entre les genres surgissent ou disparaissent. En conclusion, il importe de s'assurer que les efforts de promotion de l'activité physique tiennent compte des spécificités de genre tout en considérant les caractéristiques propres à chaque milieu. [ABSTRACT FROM AUTHOR]

A general method for the evaluation of in situ heterogeneity of geochemical materials is described and the significance of the results discussed, by using three case studies and earlier data sets. The heterogeneity of Pb in soil (expressed as RSD due to sampling, RSDsamp) varies from < 5 to > 100% between different sites, in a way that relates to the mode of deposition of the element. The heterogeneity of an element also varies systematically as a function of the distance scale at some sites. This variation can be modelled using linear regression, accounting for over 90% of the experimental variance, at seven scales over three orders of magnitude. Variation in heterogeneity between elements at the same site, seems to be somewhat diagnostic of the origin of the element, lithogenic being less than anthropogenic, although the later is also being modified by the mode of deposition. Where the heterogeneity is large (RSD > 30%), it is proposed that it can be expressed more accurately as a heterogeneity factor (10GSDsamp), to reflect its frequency distribution, which is positively skewed towards higher concentration values. [ABSTRACT FROM AUTHOR]