Exploring Metapopulation-Scale Suppression Alternatives for a Global Invader in a River Network Experiencing Climate Change

Invasive species can dramatically alter ecosystems, but eradication is difficult, and suppression is expensive once they are established. Uncertainties in the potential for expansion and impacts by an invader can lead to delayed and inadequate suppression, allowing for establishment. Metapopulation viability models can aid in planning strategies to improve responses to invaders and lessen invasive species’ impacts, which may be particularly important under climate change. We used a spatially-explicit metapopulation viability model to explore suppression strategies for ecologically-damaging invasive brown trout (Salmo trutta), established in the Colorado River and a tributary within Grand Canyon National Park. Our goals were to: 1) estimate the effectiveness of strategies targeting different life stages and subpopulations within a metapopulation, 2) quantify the effectiveness of a rapid response to a new invasion relative to delaying action until establishment; and 3) estimate whether future hydrology and temperature regimes related to climate change and reservoir management affect metapopulation viability and alter the optimal management response. We included scenarios targeting different life-stages with spatially-varying intensities of electrofishing, redd destruction, incentivized angler harvest, piscicides, and a weir. Quasi-extinction (QE) was obtainable only with metapopulation-wide suppression targeting multiple life-stages; subpopulations were most sensitive to age-0 and large adult mortality. The duration of suppression needed to reach QE for a large established subpopulation was triple compared to a rapid response to a new invasion. Isolated subpopulations were vulnerable to suppression; however, connected tributary subpopulations enhanced metapopulation persistence by serving as climate refuges. Water shortages driving changes in reservoir storage and subsequent warming would cause brown trout declines, but metapopulation QE was only achieved by re-focusing and increasing suppression. Our modeling approach improved our understanding of invasive brown trout metapopulation dynamics, which could lead to more focused and effective invasive species suppression strategies, and ultimately, maintenance of populations of endemic fishes

Secondary Lead Poisoning in Golden Eagle and Ferruginous Hawk Chicks consuming Shot Black-tailed Prairie Dogs, Thunder Basin National Grassland, Wyoming

Recreational shooting of black-tailed prairie dogs (Cynomys ludovicianus) is a common activity at Thunder Basin National Grassland (TBNG), Wyoming. The prairie dog carcasses left in the area are scavenged by coyotes (Canis latrans), raptors, and other animals. These scavengers are susceptible to lead (Pb) poisoning if they consume Pb bullet fragments or Pb shot when scavenging the shooter-killed prairie dogs. In 2000, a local rehabilitator noted an increase of Pb poisoning cases in raptors (L.Layton, pers. comm. 3/30/01) from the area. We collected several shooter-killed prairie dog carcasses from TBNG for determining if Pb fragments remained embedded in the tissue that potentially would be consumed by raptors. Radiographs showed fragments consistent with Pb to be present. In 2002, we conducted a more in-depth study to determine if Pb poisoning was occurring in raptors at TBNG by documenting the number of raptors on prairie dogs at colonies where shooting occurred, assaying bullet fragments in shot prairie dogs to determine Pb content, and analyzing blood and feather samples of ferruginous hawk (Buteo regalis) and golden eagle (Aquila chrysaetos) nestlings and feathers from burrowing owls (Athene cunicularia) for clinical signs of Pb poisoning. We observed raptors foraging at prairie dog colonies and collected data on the number of shooters shooting at prairie dog colonies. To determine if raptors preferred foraging on shot prairie dogs, we compared raptor use at prairie dog colonies where shooting occurred to raptor use at prairie dog colonies where shooting did not occur. Shooter intensity did not predict raptor use. We also collected prairie dog carcasses and examined them for Pb shot fragments. We detected metal fragments in four of ten prairie dog carcasses. The total weight of the fragments found in each carcass ranged from 10 – 146 mg. Copper was the primary metal detected in 3 of 4 carcasses; but, significant amounts of Pb (20 mg, 28 mg, and 124 mg) were found in the three carcasses. Blood Pb concentrations in ferruginous hawk nestlings were below sub-clinical levels at TBNG and the control site near Rawlins, Wyoming. Analysis of red blood cell delta-aminolevulinic acid dehydratase activity, hemoglobin levels, and protoporphyrin levels also did not indicate Pb poisoning in ferruginous hawk nestlings. Additionally, blood and feather samples from golden eagle nestlings and feather samples from burrowing owls (juveniles and adults) at TBNG did not indicate Pb poisoning. Although ferruginous hawks and golden eagles (and possibly burrowing owls) scavenge on the carcasses of shot prairie dogs and some carcasses contained Pb-bullet fragments, we did not detect Pb poisoning in any of the birds. Lead poisoning may become important if the availability of alternate food sources decreases or shooter intensity increases

Estimating Population Abundance with a Mixture of Physical Capture and PIT Tag Antenna Detection Data

The inclusion of passive interrogation antenna (PIA) detection data has promise to increase precision of population abundance estimates (Nˆ ). However, encounter probabilities are often higher for PIAs than for physical capture. If the difference is not accounted for, Nˆ may be biased. Using simulations, we estimated the magnitude of bias resulting from mixed capture and detection probabilities and evaluated potential solutions for removing the bias for closed capture models. Mixing physical capture and PIA detections (pdet) resulted in negative biases in Nˆ . However, using an individual covariate to model differences removed bias and improved precision. From a case study of fish making spawning migrations across a stream-wide PIA (pdet ≤ 0.9), the coefficient of variation (CV) of Nˆ declined 39%–82% when PIA data were included, and there was a dramatic reduction in time to detect a significant change in Nˆ . For a second case study, with modest pdet (≤0.2) using smaller PIAs, CV (Nˆ ) declined 4%–18%. Our method is applicable for estimating abundance for any situation where data are collected with methods having different capture–detection probabilities

Development of white matter circuitry in infants with fragile x syndrome

IMPORTANCE Fragile X syndrome (FXS) is a genetic neurodevelopmental disorder and the most common inherited cause of intellectual disability in males. However, there are no published data on brain development in children with FXS during infancy. OBJECTIVE To characterize the development of white matter at ages 6, 12, and 24 months in infants with FXS compared with that of typically developing controls. DESIGN, SETTING, AND PARTICIPANTS Longitudinal behavioral and brain imaging datawere collected at 1 or more time points from 27 infants with FXS and 73 typically developing controls between August 1, 2008, and June 14, 2016, at 2 academic medical centers. Infants in the control group had no first- or second-degree relatives with intellectual or psychiatric disorders, including FXS and autism spectrum disorder. MAIN OUTCOMES AND MEASURES Nineteen major white matter pathwayswere defined in common atlas space based on anatomically informed methods. Diffusion parameters, including fractional anisotropy, were compared between groups using linear mixed effects modeling. Fiber pathways showing group differences were subsequently examined in association with direct measures of verbal and nonverbal development. RESULTS There were significant differences in the development of 12 of 19 fiber tracts between the 27 infants with FXS (22 boys and 5 girls) and the 73 infants in the control group (46 boys and 27 girls), with lower fractional anisotropy in bilateral subcortical-frontal, occipital-temporal, temporal-frontal, and cerebellar-thalamic pathways, as well as 4 of 6 subdivisions of the corpus callosum. For all 12 of these pathways, there were significant main effects between groups but not for the interaction of age × group, indicating that lower fractional anisotropy was present and stable from age 6 months in infants with FXS. Lower fractional anisotropy values in the uncinate fasciculi were correlated with lower nonverbal developmental quotient in the FXS group (left uncinate, F = 10.06; false discovery rate-corrected P = .03; right uncinate, F = 21.8; P = .004). CONCLUSIONS AND RELEVANCE The results substantiate in human infants the essential role of fragile X gene expression in the early development of white matter. The findings also suggest that the neurodevelopmental effects of FXS are well established at 6 months of age

A novel method for high-dimensional anatomical mapping of extra-axial cerebrospinal fluid: Application to the infant brain

Cerebrospinal fluid (CSF) plays an essential role in early postnatal brain development. Extra-axial CSF (EA-CSF) volume, which is characterized by CSF in the subarachnoid space surrounding the brain, is a promising marker in the early detection of young children at risk for neurodevelopmental disorders. Previous studies have focused on global EA-CSF volume across the entire dorsal extent of the brain, and not regionally-specific EA-CSF measurements, because no tools were previously available for extracting local EA-CSF measures suitable for localized cortical surface analysis. In this paper, we propose a novel framework for the localized, cortical surface-based analysis of EA-CSF. The proposed processing framework combines probabilistic brain tissue segmentation, cortical surface reconstruction, and streamline-based local EA-CSF quantification. The quantitative analysis of local EA-CSF was applied to a dataset of typically developing infants with longitudinal MRI scans from 6 to 24 months of age. There was a high degree of consistency in the spatial patterns of local EA-CSF across age using the proposed methods. Statistical analysis of local EA-CSF revealed several novel findings: several regions of the cerebral cortex showed reductions in EA-CSF from 6 to 24 months of age, and specific regions showed higher local EA-CSF in males compared to females. These age-, sex-, and anatomically-specific patterns of local EA-CSF would not have been observed if only a global EA-CSF measure were utilized. The proposed methods are integrated into a freely available, open-source, cross-platform, user-friendly software tool, allowing neuroimaging labs to quantify local extra-axial CSF in their neuroimaging studies to investigate its role in typical and atypical brain development

Diffusion MRI quality control and functional diffusion map results in ACRIN 6677/RTOG 0625: A multicenter, randomized, phase II trial of bevacizumab and chemotherapy in recurrent glioblastoma

Functional diffusion mapping (fDM) is a cancer imaging technique that quantifies voxelwise changes in apparent diffusion coefficient (ADC). Previous studies have shown value of fDMs in bevacizumab therapy for recurrent glioblastoma multiforme (GBM). The aim of the present study was to implement explicit criteria for diffusion MRI quality control and independently evaluate fDM performance in a multicenter clinical trial (RTOG 0625/ACRIN 6677). A total of 123 patients were enrolled in the current multicenter trial and signed institutional review board-approved informed consent at their respective institutions. MRI was acquired prior to and 8 weeks following therapy. A 5-point QC scoring system was used to evaluate DWI quality. fDM performance was evaluated according to the correlation of these metrics with PFS and OS at the first follow-up time-point. Results showed ADC variability of 7.3% in NAWM and 10.5% in CSF. A total of 68% of patients had usable DWI data and 47% of patients had high quality DWI data when also excluding patients that progressed before the first follow-up. fDM performance was improved by using only the highest quality DWI. High pre-treatment contrast enhancing tumor volume was associated with shorter PFS and OS. A high volume fraction of increasing ADC after therapy was associated with shorter PFS, while a high volume fraction of decreasing ADC was associated with shorter OS. In summary, DWI in multicenter trials are currently of limited value due to image quality. Improvements in consistency of image quality in multicenter trials are necessary for further advancement of DWI biomarkers

Functional neuroimaging of high-risk 6-month-old infants predicts a diagnosis of autism at 24 months of age

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social deficits and repetitive behaviors that typically emerge by 24 months of age. To develop effective early interventions that can potentially ameliorate the defining deficits of ASD and improve long-term outcomes, early detection is essential. Using prospective neuroimaging of 59 6-month-old infants with a high familial risk for ASD, we show that functional connectivity magnetic resonance imaging correctly identified which individual children would receive a research clinical best-estimate diagnosis of ASD at 24 months of age. Functional brain connections were defined in 6-month-old infants that correlated with 24-month scores on measures of social behavior, language, motor development, and repetitive behavior, which are all features common to the diagnosis of ASD. A fully cross-validated machine learning algorithm applied at age 6 months had a positive predictive value of 100% [95% confidence interval (CI), 62.9 to 100], correctly predicting 9 of 11 infants who received a diagnosis of ASD at 24 months (sensitivity, 81.8%; 95% CI, 47.8 to 96.8). All 48 6-month-old infants who were not diagnosed with ASD were correctly classified [specificity, 100% (95% CI, 90.8 to 100); negative predictive value, 96.0% (95% CI, 85.1 to 99.3)]. These findings have clinical implications for early risk assessment and the feasibility of developing early preventative interventions for ASD

Increased Extra-axial Cerebrospinal Fluid in High-Risk Infants Who Later Develop Autism

Background We previously reported that infants who developed autism spectrum disorder (ASD) had increased cerebrospinal fluid (CSF) in the subarachnoid space (i.e., extra-axial CSF) from 6 to 24 months of age. We attempted to confirm and extend this finding in a larger independent sample. Methods A longitudinal magnetic resonance imaging study of infants at risk for ASD was carried out on 343 infants, who underwent neuroimaging at 6, 12, and 24 months. Of these infants, 221 were at high risk for ASD because of an older sibling with ASD, and 122 were at low risk with no family history of ASD. A total of 47 infants were diagnosed with ASD at 24 months and were compared with 174 high-risk and 122 low-risk infants without ASD. Results Infants who developed ASD had significantly greater extra-axial CSF volume at 6 months compared with both comparison groups without ASD (18% greater than high-risk infants without ASD; Cohen's d = 0.54). Extra-axial CSF volume remained elevated through 24 months (d = 0.46). Infants with more severe autism symptoms had an even greater volume of extra-axial CSF from 6 to 24 months (24% greater at 6 months, d = 0.70; 15% greater at 24 months, d = 0.70). Extra-axial CSF volume at 6 months predicted which high-risk infants would be diagnosed with ASD at 24 months with an overall accuracy of 69% and corresponding 66% sensitivity and 68% specificity, which was fully cross-validated in a separate sample. Conclusions This study confirms and extends previous findings that increased extra-axial CSF is detectable at 6 months in high-risk infants who develop ASD. Future studies will address whether this anomaly is a contributing factor to the etiology of ASD or an early risk marker for ASD

Lynx Mission Concept Status

Lynx is a concept under study for prioritization in the 2020 Astrophysics Decadal Survey. Providing orders of magnitude increase in sensitivity over Chandra, Lynx will examine the first black holes and their galaxies, map the large-scale structure and galactic halos, and shed new light on the environments of young stars and their planetary systems. In order to meet the Lynx science goals, the telescope consists of a high-angular resolution optical assembly complemented by an instrument suite that may include a High Definition X-ray Imager, X-ray Microcalorimeter and an X-ray Grating Spectrometer. The telescope is integrated onto the spacecraft to form a comprehensive observatory concept. Progress on the formulation of the Lynx telescope and observatory configuration is reported in this paper