Toward an internally consistent astronomical distance scale

Accurate astronomical distance determination is crucial for all fields in astrophysics, from Galactic to cosmological scales. Despite, or perhaps because of, significant efforts to determine accurate distances, using a wide range of methods, tracers, and techniques, an internally consistent astronomical distance framework has not yet been established. We review current efforts to homogenize the Local Group's distance framework, with particular emphasis on the potential of RR Lyrae stars as distance indicators, and attempt to extend this in an internally consistent manner to cosmological distances. Calibration based on Type Ia supernovae and distance determinations based on gravitational lensing represent particularly promising approaches. We provide a positive outlook to improvements to the status quo expected from future surveys, missions, and facilities. Astronomical distance determination has clearly reached maturity and near-consistency.Comment: Review article, 59 pages (4 figures); Space Science Reviews, in press (chapter 8 of a special collection resulting from the May 2016 ISSI-BJ workshop on Astronomical Distance Determination in the Space Age

Astronomical Distance Determination in the Space Age: Secondary Distance Indicators

The formal division of the distance indicators into primary and secondary leads to difficulties in description of methods which can actually be used in two ways: with, and without the support of the other methods for scaling. Thus instead of concentrating on the scaling requirement we concentrate on all methods of distance determination to extragalactic sources which are designated, at least formally, to use for individual sources. Among those, the Supernovae Ia is clearly the leader due to its enormous success in determination of the expansion rate of the Universe. However, new methods are rapidly developing, and there is also a progress in more traditional methods. We give a general overview of the methods but we mostly concentrate on the most recent developments in each field, and future expectations. © 2018, The Author(s)

Short-term response of sage-grouse nesting to conifer removal in the northern great basin

Coniferwoodlands expanding into sage-steppe (Artemisia spp.) are a threat to sagebrush obligate species including the imperiled greater sage-grouse (Centrocercus urophasianus). Conifer removal is accelerating rapidly despite a lack of empirical evidence to assess outcomes to grouse. Using a before-after-control-impact design, we evaluated short-term effects of conifer removal on nesting habitat use by monitoring 262 sage-grouse nests in the northern Great Basin during 2010-2014. Tree removal made available for nesting an additional 28% of the treatment landscape by expanding habitat an estimated 9603 ha (3201 ha [±480 SE] annually). Relative probability of nesting in newly restored sites increased by 22% annually, and femaleswere 43%more likely to nestwithin 1000 m of treatments. From 2011 (pretreatment) to 2014 (3 yr after treatments began), 29% of the marked population (9.5% [±1.2 SE] annually) had shifted its nesting activities into mountain big sagebrush habitats that were cleared of encroaching conifer. Grouping treatments likely contributed to beneficial outcomes for grouse as individual removal projects averaged just 87 ha in size but cumulatively covered a fifth of the study area. Collaboratively identifying future priority watersheds and implementing treatments across public and private ownerships is vital to effectively restore the sage-steppe ecosystem for nesting sage-grouse.The Rangeland Ecology & Management archives are made available by the Society for Range Management and the University of Arizona Libraries. Contact [email protected] for further information

Phytoremediation and high rainfall combine to improve soil and plant health in a North America Northern Great Plains saline sodic soil

Saline/sodic soils are often remediated by applying gypsum, improving drainage, and irrigating with high quality water. However, these management approaches may not be effective or feasible in dryland soils supersaturated with gypsum. A field study, conducted between 2017 and 2021, investigated the effect of phytoremediation on soil and plant health in a landscape containing productive, transition, and saline/sodic soils. Phytoremediation treatments–corn (Zea mays) and two perennial grass mixes (mix 1 slender wheatgrass [Elymus trachycaulus] and beardless wildrye [Leymus triticoides], and mix 2 slender wheatgrass, creeping meadow foxtail [Alopecurus arundinaceus], western wheatgrass [Agropyron smithii], and green wheatgrass [Elymus Hoffmannii])–were planted and compared with a no-plant control treatment across three soil zones. Perennial grasses were dormant seeded in the winter of 2017 and 2018, and corn was grown in 2018, 2019, and 2020. Soil samples (0 to 15 cm) were collected on July 24, 2018, July 23, 2019, July 24, 2020, and April 15, 2021. Across soil zones, corn production was 5,990 (grain + stover), 3,900 (stover only), and 6,150 (grain + stover) kg ha−1 in 2018, 2019, and 2020, respectively, whereas perennial grass biomass yields averaged 1,220, 9,065, and 7,375 kg ha−1 in 2018, 2019, and 2020, respectively. Due to high rainfall that occurred from the fall of 2018 through the summer of 2019, the depth to the water table decreased and the soil electrical conductivity (EC1:1) (−0.83 ± 0.149 dS m−1) and exchangeable sodium (Na+) (−656 ± 220) decreased in all treatments. In addition, from 2018 to 2019, the risk of soil dispersion (lower Na+/EC1:1 ratio) was less in treatments with growing plants (p = 0.02) than plots without plants. With drier conditions from the fall of 2019 through the spring of 2021, the depth to groundwater increased, the EC1:1 decreased in the transition soil but increased in the saline/sodic soil (p = 0.001), and the Na+/EC1:1 ratio increased in the productive and transition soils and was static or decreased in the saline/sodic soil (p = 0.001). In conclusion, this and related work showed that phytoremediation when combined with high natural rainfall reduced soil EC1:1 and the exchangeable Na+ in all soils; however, these benefits may be short lived, and as the water tables dropped in 2020, EC1:1 increased in the saline/sodic zones. Laboratory and linked research from the study site also showed that fertilizing saline sodic soils can result in very high nitrous oxide (N2O) emissions, and reseeding degraded soil to perennial plants provides soil cover that reduces the risk of erosion and provides habitat for wildlife

Silhouette showcards confirm altered obesity-associated body image perception in international cohort study of African-origin populations.

Given the increasing prevalence of obesity and need for effective interventions, there is a growing interest in understanding how an individual's body image can inform obesity prevention and management. This study's objective was to examine the use of silhouette showcards to measure body size perception compared with measured body mass index, and assess body size dissatisfaction, in three different African-origin populations spanning the epidemiological transition. An ancillary objective was to investigate associations between body size perception and dissatisfaction with diabetes and hypertension. Research visits were completed in local research clinics in respective countries. Seven hundred and fifty-one African-origin participants from the USA and the Republic of Seychelles (both high-income countries), and Ghana (low/middle-income country). Silhouette showcards were used to measure perceived body size and body size dissatisfaction. Objectively measured body size was measured using a scale and stadiometer. Diabetes was defined as fasting blood glucose ≥126 mg/dL and hypertension was defined as ≥130 mm Hg/80 mm Hg. Most women and men from the USA and Seychelles had 'Perceived minus Actual weight status Discrepancy' scores less than 0, meaning they underestimated their actual body size. Similarly, most overweight or obese men and women also underestimated their body size, while normal weight men and women were accurately able to estimate their body size. Finally, participants with diabetes were able to accurately estimate their body size and similarly desired a smaller body size. This study highlights that overweight and obese women and men from countries spanning the epidemiological transition were unable to accurately perceive their actual body size. Understanding people's perception of their body size is critical to implementing successful obesity prevention programmes across the epidemiological transition