Landmark-dependent Navigation Strategy Declines across the Human Life-Span: Evidence from Over 37,000 Participants

Humans show a remarkable capacity to navigate various environments using different navigation strategies, and we know that strategy changes across the life span. However, this observation has been based on studies of small sample sizes. To this end, we used a mobile app-based video game (Sea Hero Quest) to test virtual navigation strategies and memory performance within a distinct radial arm maze level in over 37,000 participants. Players were presented with 6 pathways (3 open and 3 closed) and were required to navigate to the 3 open pathways to collect a target. Next, all 6 pathways were made available and the player was required to visit the pathways that were previously unavailable. Both reference memory and working memory errors were calculated. Crucially, at the end of the level, the player was asked a multiple-choice question about how they found the targets (i.e., a counting-dependent strategy vs. a landmark-dependent strategy). As predicted from previous laboratory studies, we found the use of landmarks declined linearly with age. Those using landmark-based strategies also performed better on reference memory than those using a counting-based strategy. These results extend previous observations in the laboratory showing a decreased use of landmark-dependent strategies with age

Mississippian Stratigraphic Nomenclature Revisions in Kansas

This paper reviews proposed Mississippian nomenclature changes in Kansas and outlines the changes to Zeller (1968) that have been adopted by the Kansas Geological Survey. The Sedalia Dolomite is changed to the Sedalia Formation and the Northview Shale is changed to Northview Formation due to lateral lithology changes. The Short Creek Oolite Member as originally defined and described by Smith and Siebenthal (1907) at the type section in Kansas is reinstated. The Cowley Formation as originally defined and described by Lee (1940) in Kansas is reinstated. The Ste. Genevieve Limestone is placed as the basal formation of the Chesteran Stage

Quaternary Stratigraphy and Stratigraphic Nomenclature Revisions in Kansas

This paper outlines Quaternary nomenclature changes to Zeller (1968) that have been adopted by the Kansas Geological Survey (KGS). The KGS formally recognizes two series/epochs for the Quaternary: the Holocene and Pleistocene. Pleistocene stage/age names Kansan, Aftonian, Nebraskan, and Yarmouthian are abandoned and replaced with the broader term "pre-Illinoian." Formation names Bignell, Peoria, Gilman Canyon, and Loveland are maintained for loess units. Formation names for the following alluvial lithostratigraphic units are abandoned: Crete, Sappa, Grand Island, Fullerton, and Holdrege. The Severance Formation is adopted as a new lithostratigraphic unit for thick packages of late Pleistocene alluvium and colluvium in Kansas. The DeForest Formation is accepted as a valid lithostratigraphic unit for deposits of fine-grained Holocene alluvium in Kansas. Formation names Iowa Point, Nickerson, and Cedar Bluffs for glacial tills and Atchison and David City for glaciofluvial deposits are abandoned. The Afton and Yarmouth Soils are abandoned as pedostratigraphic units, whereas the Sangamon Geosol and Brady Geosol are maintained

Considering environmental factors, navigation strategies, and age

Sex differences in navigation have been a topic of investigation for decades and has been subjected to various contradictory findings and debates. The aim of this work was to compare the spatial memory of men and women tested in various different types of spatial tasks, while controlling for navigation strategies and aging. It is generally thought that men outperform women in navigation and that women have higher scores on object location tasks. However, many studies fail to control for different factors that may bias one sex or the other. We aggregated the data of 465 participants (349 young adults, 127 older adults) who took part in various studies conducted in our laboratory, which include both published and original unpublished data, in order to investigate sex differences. In these studies, we used a number of different paradigms: virtual radial arm mazes, a virtual wayfinding task, an object location task, a virtual Morris Water Maze, and the invisible sensor task which is a real-life model of the Morris Water Maze. While our results may seem discordant at first glance, they demonstrate that several factors can impact the performance of men and women on spatial tasks, including spontaneous navigation strategies, environmental characteristics, and age. We replicated findings showing that women favor proximal landmarks compared to men who favor distal landmarks, women have better memory than men for the position of objects in the absence of reference frames, but they will have poorer scores when navigation requires specific angles, distances and polar coordinates. Moreover, we found that in aging, women who avoid the use of landmarks when navigating a radial maze show stronger reliance on these non-spatial strategies than men. On the other hand, women who rely on landmarks, do so to the same extent as men. Our findings highlight the need to carefully take into consideration these factors in order to produce a more harmonious understanding of sex differences in navigation. Finally, the interaction between spontaneous navigation strategies, sex, and age is discussed in terms of its implications for risk of Alzheimer’s disease

Magnetic inflation and Stellar Mass. II. On the radii of wingle, rapidly rotating, fully convective M-dwarf stars

Main-sequence, fully convective M dwarfs in eclipsing binaries are observed to be larger than stellar evolutionary models predict by as much as 10%–15%. A proposed explanation for this discrepancy involves effects from strong magnetic fields, induced by rapid rotation via the dynamo process. Although, a handful of single, slowly rotating M dwarfs with radius measurements from interferometry also appear to be larger than models predict, suggesting that rotation or binarity specifically may not be the sole cause of the discrepancy. We test whether single, rapidly rotating, fully convective stars are also larger than expected by measuring their $R\sin i$ distribution. We combine photometric rotation periods from the literature with rotational broadening ($v\sin i$) measurements reported in this work for a sample of 88 rapidly rotating M dwarf stars. Using a Bayesian framework, we find that stellar evolutionary models underestimate the radii by 10 \% \mbox{--}15{ \% }_{-2.5}^{+3}, but that at higher masses (0.18 < M < 0.4 M Sun), the discrepancy is only about 6% and comparable to results from interferometry and eclipsing binaries. At the lowest masses (0.08 < M < 0.18 M Sun), we find that the discrepancy between observations and theory is 13%–18%, and we argue that the discrepancy is unlikely to be due to effects from age. Furthermore, we find no statistically significant radius discrepancy between our sample and the handful of M dwarfs with interferometric radii. We conclude that neither rotation nor binarity are responsible for the inflated radii of fully convective M dwarfs, and that all fully convective M dwarfs are larger than models predict.The authors would like to thank the referee for the thoughtful report, which greatly improved the manuscript. The authors would also like to thank Lisa Prato and Larissa Nofi for IGRINS training, and Heidi Larson, Jason Sanborn, and Andrew Hayslip for operating the DCT during our observations. We would also like to thank Jen Winters, Jonathan Irwin, Paul Dalba, Mark Veyette, Eunkyu Han, and Andrew Vanderburg for useful discussions and helpful comments on this work. Some of this work was supported by the NASA Exoplanet Research Program (XRP) under grant No. NNX15AG08G issued through the Science Mission Directorate.These results made use of the Lowell Observatory's Discovery Channel Telescope, supported by Discovery Communications, Inc., Boston University, the University of Maryland, the University of Toledo and Northern Arizona University; the Immersion Grating Infrared Spectrograph (IGRINS) that was developed under a collaboration between the University of Texas at Austin and the Korea Astronomy and Space Science Institute (KASI) with the financial support of the US National Science Foundation under grant AST-1229522, of the University of Texas at Austin, and of the Korean GMT Project of KASI; data taken at The McDonald Observatory of The University of Texas at Austin; and data products from the Two Micron All Sky Survey, which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology, funded by NASA and the NSF. (NNX15AG08G - NASA Exoplanet Research Program (XRP); Discovery Communications, Inc.; Boston University; University of Maryland; University of Toledo; Northern Arizona University; AST-1229522 - US National Science Foundation; University of Texas at Austin; Korean GMT Project of KASI; NASA; NSF

Expression quantitative trait loci are highly sensitive to cellular differentiation state

Blood cell development from multipotent hematopoietic stem cells to specialized blood cells is accompanied by drastic changes in gene expression for which the triggers remain mostly unknown. Genetical genomics is an approach linking natural genetic variation to gene expression variation, thereby allowing the identification of genomic loci containing gene expression modulators (eQTLs). In this paper, we used a genetical genomics approach to analyze gene expression across four developmentally close blood cell types collected from a large number of genetically different but related mouse strains. We found that, while a significant number of eQTLs (365) had a consistent “static” regulatory effect on gene expression, an even larger number were found to be very sensitive to cell stage. As many as 1,283 eQTLs exhibited a “dynamic” behavior across cell types. By looking more closely at these dynamic eQTLs, we show that the sensitivity of eQTLs to cell stage is largely associated with gene expression changes in target genes. These results stress the importance of studying gene expression variation in well-defined cell populations. Only such studies will be able to reveal the important differences in gene regulation between different ce

Advances in Distinguishing Groundwater Influenced by Oil Sands Process-Affected Water (OSPW) from Natural Bitumen-Influenced Groundwater

The objective of this study was to advance analytical methods for detecting oil sands process-affected water (OSPW) seepage from mining containments and discriminating any such seepage from the natural bitumen background in groundwaters influenced by the Alberta McMurray formation. Improved sampling methods and quantitative analyses of two groups of monoaromatic acids were employed to analyze OSPW and bitumen-affected natural background groundwaters for source discrimination. Both groups of monoaromatic acids showed significant enrichment in OSPW, while ratios of O /O containing heteroatomic ion classes of acid extractable organics (AEOs) did not exhibit diagnostic differences. Evaluating the monoaromatic acids to track a known plume of OSPW-affected groundwater confirmed their diagnostic abilities. A secondary objective was to assess anthropogenically derived artificial sweeteners and per- and polyfluoroalkyl substances (PFAS) as potential tracers for OSPW. Despite the discovery of acesulfame and PFAS in most OSPW samples, trace levels in groundwaters influenced by general anthropogenic activities preclude them as individual robust tracers. However, their inclusion with the other metrics employed in this study served to augment the tiered, weight of evidence methodology developed. This methodology was then used to confirm earlier findings of OSPW migrations into groundwater reaching the Athabasca River system adjacent to the reclaimed pond at Tar Island Dyke

Immune or genetic-mediated disruption of CASPR2 causes pain hypersensitivity due to enhanced primary afferent excitability

Human autoantibodies to contactin-associated protein-like 2 (CASPR2) are often associated with neuropathic pain, and CASPR2 mutations have been linked to autism spectrum disorders, in which sensory dysfunction is increasingly recognized. Human CASPR2 autoantibodies, when injected into mice, were peripherally restricted and resulted in mechanical pain-related hypersensitivity in the absence of neural injury. We therefore investigated the mechanism by which CASPR2 modulates nociceptive function. Mice lacking CASPR2 (Cntnap2 ) demonstrated enhanced pain-related hypersensitivity to noxious mechanical stimuli, heat, and algogens. Both primary afferent excitability and subsequent nociceptive transmission within the dorsal horn were increased in Cntnap2 mice. Either immune or genetic-mediated ablation of CASPR2 enhanced the excitability of DRG neurons in a cell-autonomous fashion through regulation of Kv1 channel expression at the soma membrane. This is the first example of passive transfer of an autoimmune peripheral neuropathic pain disorder and demonstrates that CASPR2 has a key role in regulating cell-intrinsic dorsal root ganglion (DRG) neuron excitability

True interindividual variability exists in postprandial appetite responses in healthy men but is not moderated by the FTO genotype

Background: After meal ingestion, a series of coordinated hormone responses occur concomitantly with changes in perceived appetite. It is not known whether interindividual variability in appetite exists in response to a meal. Objectives: This study aimed to 1) assess the reproducibility of appetite responses to a meal; 2) quantify individual differences in responses; and 3) explore any moderating influence of the fat mass and obesity associated (FTO) gene. Methods: Using a replicated crossover design, 18 healthy men (mean ± SD 28.5 ± 9.8 years, 27.0 ± 5.0 kg·m-2 ) recruited according to FTO genotype (9 AA, 9 TT) completed two identical control and two identical standardized meal conditions (5025 kJ) in randomized sequences. Perceived appetite and plasma acylated ghrelin, total peptide YY (PYY), insulin and glucose concentrations were measured before and after interventions as primary outcomes. Interindividual differences were explored using Pearson’s product-moment correlations between the first and second replicate of the control-adjusted meal response. Within-participant covariate-adjusted linear mixed models were used to quantify participant by-condition and genotype-by-condition interactions. Results: The meal suppressed acylated ghrelin and appetite perceptions (standardized effect sizes (ES): 0.18-4.26) and elevated total PYY, insulin and glucose (ES: 1.96-21.60). For all variables, SD of change scores was greater in the meal versus control conditions. Moderate-to-large positive correlations were observed between the two replicates of control-adjusted meal responses for all variables (r=0.44-0.86, P≤0.070). Participant-by-condition interactions were present for all variables (P≤0.056). FTO genotype-by-condition interactions were not significant (P≥0.19) and treatment effect differences between genotype groups were small (ES≤0.27) for all appetite parameters. Conclusions: Reproducibility of postprandial appetite responses is generally good. True interindividual variability is present beyond any random within-subject variation in healthy men but is not moderated by the FTO genotype. These findings highlight the 3 importance of exploring individual differences in appetite for the prevention and/or treatment of obesity. Clinical trial registry number: NCT03771690 (ClinicalTrials.gov)