Lynx X-Ray Observatory: Response to the First Astro 2020 Decadal Survey Request for Information

This document serves as the Lynx Teams response to the first Request For Information (RFI) from the 2020 Decadal Survey in Astronomy and Astrophysics. Detailed answers to all of the questions asked in this RFI can be found in the Lynx Concept Study Report, Supplementary Technology Roadmaps, and the Lynx Cost Book

Effect of beef heifer development systems utilizing corn residue and late summer planted cover crops on growth, reproductive performance, and economics

The objective of this study was to evaluate growth and reproductive performance of heifers developed using 3 different winter systems in the midwestern U.S. Spring-born heifers (n = 1,156; 214 d of age; SD ± 17 d) were used in a 3-yr study to evaluate performance in winter development systems, which utilized cover crop (CC) and corn residue grazing. Heifers were assigned to 1 of 3 treatments: grazing corn residue with 0.77 kg/d dried distillers grains (CD) or 1.69 kg/d wheat midds (CW) supplementation followed by a grower ration in the drylot, or grazing late summer planted oat-brassica CC followed by corn residue grazing with 0.35 kg/d dried distillers grains supplementation (CC). Supplementation during the corn residue phase was targeted to result in a common body weight (BW) (276 kg; ~45% of mature BW) by the end of the winter development period. Grazing of corn residue (CD and CW) and CC began in early November. After 63 d, heifers assigned to CC were moved to corn residue; on day 77 heifers assigned to CD and CW began receiving a grower ration in the drylot. In mid-February (day 98), heifers were comingled and managed in a single group. Breeding season began in June and lasted for 29 d. The ADG of heifers assigned to CC when grazing CC (days 1 to 63) was greater (0.76 kg/d; P \u3c 0.01) than those assigned to CD or CW (0.58 kg/d and 0.49 kg/d, respectively). Gain during the last 35 d of the winter period for heifers assigned to CC (0.36 kg/d) was less (P \u3c 0.01) than those assigned to CW (0.49 kg/d) but not different from CD heifers (0.41 kg/d). Overall (days 1 to 98), winter ADG was greater (P \u3c 0.05) for heifers assigned to CC (0.62 kg/d) than CD (0.53 kg/d) or CW (0.50 kg/d), which did not differ (P = 0.42). Percent of mature BW in May (27 d pre-breeding) was greater (P \u3c 0.01) for heifers assigned to CC (52%) than for those on CD and CW (50%), which did not differ (P = 0.64). Pregnancy rates were affected by treatment (P \u3c 0.03), with heifers assigned to CC (76%) being greater than CW (64%) and CD heifers being intermediate (70%). When accounting for the differences in cost and the value of open and bred heifers, the economic return tended to differ (P = 0.07) among treatments, with CC and CW not differing (P ≥ 0.20) from CD but return for CC being $73 greater than CW (P = 0.02). Utilizing oat-brassica CCs early in the winter followed by a slower rate of gain while grazing corn residue with distillers supplementation appears to be as effective for developing beef heifers in the midwestern U.S. as supplementing distillers grains

Seasonal Patterns in Stable Isotope and Fatty Acid Profiles of Southern Stingrays (Hypanus americana) at Stingray City Sandbar, Grand Cayman

Ecotourism opportunities in the marine environment often rely heavily on provisioning to ensure the viewing of cryptic species by the public. However, intentional feeding of wildlife can impact numerous aspects of an animals’ behavior and ecology. Southern stingrays (Hypanus americana) provisioned at Stingray City Sandbar (SCS) in Grand Cayman have altered diel activity patterns and decreased measures of health. This study looked at seasonal changes in stable isotope (SI) and fatty acid (FA) profiles of provisioned stingrays at SCS. Plasma δ15N was higher in male stingrays (11.86 ± 1.71‰) compared to females (10.70 ± 1.71‰). Lower values for δ15N in males and females were measured in October during low tourist season, suggesting stingrays may be forced to rely on native prey items to supplement the decreased amount of provisioned squid available during this time. Plasma FA profiles were significantly different between sexes and across sampling time points, with FAs 22:6n3, 16:0, 20:5n3, 18:1n3C, 18:0 and 18:1n9T contributing to dissimilarity scores between groups. Dietary FAs primarily contributed to differences between males and females lending further evidence to differences in foraging patterns at SCS, likely due to intraspecific competition. Further, canonical analysis of principal coordinates (CAP) analysis of FA profiles suggest similar diets during peak tourist season and differences in diet between males and females during the low season. This study demonstrates alterations in feeding ecology in stingrays at SCS which is of critical importance for effective management of the SCS aggregation

Lynx X-Ray Observatory: An Overview

Lynx, one of the four strategic mission concepts under study for the 2020 Astrophysics Decadal Survey, provides leaps in capability over previous and planned x-ray missions and provides synergistic observations in the 2030s to a multitude of space- and ground-based observatories across all wavelengths. Lynx provides orders of magnitude improvement in sensitivity, on-axis subarcsecond imaging with arcsecond angular resolution over a large field of view, and high-resolution spectroscopy for point-like and extended sources in the 0.2- to 10-keV range. The Lynx architecture enables a broad range of unique and compelling science to be carried out mainly through a General Observer Program. This program is envisioned to include detecting the very first seed black holes, revealing the high-energy drivers of galaxy formation and evolution, and characterizing the mechanisms that govern stellar evolution and stellar ecosystems. The Lynx optics and science instruments are carefully designed to optimize the science capability and, when combined, form an exciting architecture that utilizes relatively mature technologies for a cost that is compatible with the projected NASA Astrophysics budget

A Preliminary DTI Tractography Study of Developmental Neuroplasticity 5-15 Years After Early Childhood Traumatic Brain Injury

Plasticity is often implicated as a reparative mechanism when addressing structural and functional brain development in young children following traumatic brain injury (TBI); however, conventional imaging methods may not capture the complexities of post-trauma development. The present study examined the cingulum bundles and perforant pathways using diffusion tensor imaging (DTI) in 21 children and adolescents (ages 10-18 years) 5-15 years after sustaining early childhood TBI in comparison with 19 demographically-matched typically-developing children. Verbal memory and executive functioning were also evaluated and analyzed in relation to DTI metrics. Beyond the expected direction of quantitative DTI metrics in the TBI group, we also found qualitative differences in the streamline density of both pathways generated from DTI tractography in over half of those with early TBI. These children exhibited hypertrophic cingulum bundles relative to the comparison group, and the number of tract streamlines negatively correlated with age at injury, particularly in the late-developing anterior regions of the cingulum; however, streamline density did not relate to executive functioning. Although streamline density of the perforant pathway was not related to age at injury, streamline density of the left perforant pathway was significantly and positively related to verbal memory scores in those with TBI, and a moderate effect size was found in the right hemisphere. DTI tractography may provide insight into developmental plasticity in children post-injury. While traditional DTI metrics demonstrate expected relations to cognitive performance in group-based analyses, altered growth is reflected in the white matter structures themselves in some children several years post-injury. Whether this plasticity is adaptive or maladaptive, and whether the alterations are structure-specific, warrants further investigation

Marine heatwaves threaten global biodiversity and the provision of ecosystem services

The global ocean has warmed substantially over the past century, with far-reaching implications for marine ecosystems 1 . Concurrent with long-term persistent warming, discrete periods of extreme regional ocean warming (marine heatwaves, MHWs) have increased in frequency 2 . Here we quantify trends and attributes of MHWs across all ocean basins and examine their biological impacts from species to ecosystems. Multiple regions in the Pacific, Atlantic and Indian Oceans are particularly vulnerable to MHW intensification, due to the co-existence of high levels of biodiversity, a prevalence of species found at their warm range edges or concurrent non-climatic human impacts. The physical attributes of prominent MHWs varied considerably, but all had deleterious impacts across a range of biological processes and taxa, including critical foundation species (corals, seagrasses and kelps). MHWs, which will probably intensify with anthropogenic climate change 3 , are rapidly emerging as forceful agents of disturbance with the capacity to restructure entire ecosystems and disrupt the provision of ecological goods and services in coming decades. © 2019, The Author(s), under exclusive licence to Springer Nature Limited

Association of Genetic Variants With Primary Open-Angle Glaucoma Among Individuals With African Ancestry.

Importance:Primary open-angle glaucoma presents with increased prevalence and a higher degree of clinical severity in populations of African ancestry compared with European or Asian ancestry. Despite this, individuals of African ancestry remain understudied in genomic research for blinding disorders. Objectives:To perform a genome-wide association study (GWAS) of African ancestry populations and evaluate potential mechanisms of pathogenesis for loci associated with primary open-angle glaucoma. Design, Settings, and Participants:A 2-stage GWAS with a discovery data set of 2320 individuals with primary open-angle glaucoma and 2121 control individuals without primary open-angle glaucoma. The validation stage included an additional 6937 affected individuals and 14 917 unaffected individuals using multicenter clinic- and population-based participant recruitment approaches. Study participants were recruited from Ghana, Nigeria, South Africa, the United States, Tanzania, Britain, Cameroon, Saudi Arabia, Brazil, the Democratic Republic of the Congo, Morocco, Peru, and Mali from 2003 to 2018. Individuals with primary open-angle glaucoma had open iridocorneal angles and displayed glaucomatous optic neuropathy with visual field defects. Elevated intraocular pressure was not included in the case definition. Control individuals had no elevated intraocular pressure and no signs of glaucoma. Exposures:Genetic variants associated with primary open-angle glaucoma. Main Outcomes and Measures:Presence of primary open-angle glaucoma. Genome-wide significance was defined as P < 5 × 10-8 in the discovery stage and in the meta-analysis of combined discovery and validation data. Results:A total of 2320 individuals with primary open-angle glaucoma (mean [interquartile range] age, 64.6 [56-74] years; 1055 [45.5%] women) and 2121 individuals without primary open-angle glaucoma (mean [interquartile range] age, 63.4 [55-71] years; 1025 [48.3%] women) were included in the discovery GWAS. The GWAS discovery meta-analysis demonstrated association of variants at amyloid-β A4 precursor protein-binding family B member 2 (APBB2; chromosome 4, rs59892895T>C) with primary open-angle glaucoma (odds ratio [OR], 1.32 [95% CI, 1.20-1.46]; P = 2 × 10-8). The association was validated in an analysis of an additional 6937 affected individuals and 14 917 unaffected individuals (OR, 1.15 [95% CI, 1.09-1.21]; P < .001). Each copy of the rs59892895*C risk allele was associated with increased risk of primary open-angle glaucoma when all data were included in a meta-analysis (OR, 1.19 [95% CI, 1.14-1.25]; P = 4 × 10-13). The rs59892895*C risk allele was present at appreciable frequency only in African ancestry populations. In contrast, the rs59892895*C risk allele had a frequency of less than 0.1% in individuals of European or Asian ancestry. Conclusions and Relevance:In this genome-wide association study, variants at the APBB2 locus demonstrated differential association with primary open-angle glaucoma by ancestry. If validated in additional populations this finding may have implications for risk assessment and therapeutic strategies

Induction of neural crest stem cells from Bardet–Biedl syndrome patient derived hiPSCs

Neural crest cells arise in the embryo from the neural plate border and migrate throughout the body, giving rise to many different tissue types such as bones and cartilage of the face, smooth muscles, neurons, and melanocytes. While studied extensively in animal models, neural crest development and disease have been poorly described in humans due to the challenges in accessing embryonic tissues. In recent years, patient-derived human induced pluripotent stem cells (hiPSCs) have become easier to generate, and several streamlined protocols have enabled robust differentiation of hiPSCs to the neural crest lineage. Thus, a unique opportunity is offered for modeling neurocristopathies using patient specific stem cell lines. In this work, we make use of hiPSCs derived from patients affected by the Bardet–Biedl Syndrome (BBS) ciliopathy. BBS patients often exhibit subclinical craniofacial dysmorphisms that are likely to be associated with the neural crest-derived facial skeleton. We focus on hiPSCs carrying variants in the BBS10 gene, which encodes a protein forming part of a chaperonin-like complex associated with the cilium. Here, we establish a pipeline for profiling hiPSCs during differentiation toward the neural crest stem cell fate. This can be used to characterize the differentiation properties of the neural crest-like cells. Two different BBS10 mutant lines showed a reduction in expression of the characteristic neural crest gene expression profile. Further analysis of both BBS10 mutant lines highlighted the inability of these mutant lines to differentiate toward a neural crest fate, which was also characterized by a decreased WNT and BMP response. Altogether, our study suggests a requirement for wild-type BBS10 in human neural crest development. In the long term, approaches such as the one we describe will allow direct comparison of disease-specific cell lines. This will provide valuable insights into the relationships between genetic background and heterogeneity in cellular models. The possibility of integrating laboratory data with clinical phenotypes will move us toward precision medicine approaches

Characterizing Hypertension Specialist Care in Canada: A National Survey

BACKGROUND: The hypertension specialist often receives referrals of patients with young-onset, severe, difficult-to-control hypertension, patients with hypertensive emergencies, and patients with secondary causes of hypertension. Specialist hypertension care compliments primary care for these complex patients and contributes to an overall hypertension control strategy. The objective of this study was to characterize hypertension centres and the practice patterns of Canadian hypertension specialists. METHODS: Adult hypertension specialists across Canada were surveyed to describe hypertension centres and specialist practice in Canada, including the following: the patient population managed by hypertension specialists; details on how care is provided; practice pattern variations; and differences in access to specialized hypertension resources across the country. RESULTS: The survey response rate was 73.5% from 25 hypertension centres. Most respondents were nephrologists and general internal medicine specialists. Hypertension centres saw between 50 and 2500 patients yearly. A mean of 17% (± 15%) of patients were referred from the emergency department and a mean of 52% (± 24%) were referred from primary care. Most centres had access to specialized testing (adrenal vein sampling, level 1 sleep studies, autonomic testing) and advanced therapies for resistant hypertension (renal denervation). Considerable heterogeneity was present in the target blood pressure in young people with low cardiovascular risk and in the diagnostic algorithms for investigating secondary causes of hypertension. CONCLUSIONS: These results summarize the current state of hypertension specialist care and highlight opportunities for further collaboration among hypertension specialists, including standardization of the approach to specialist care for patients with hypertension