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Cognitive training has shown promise for improving cognition in older adults. Aging involves a variety of neuroanatomical changes that may affect response to cognitive training. White matter hyperintensities (WMH) are one common age-related brain change, as evidenced by T2-weighted and Fluid Attenuated Inversion Recovery (FLAIR) MRI. WMH are associated with older age, suggestive of cerebral small vessel disease, and reflect decreased white matter integrity. Higher WMH load associates with reduced threshold for clinical expression of cognitive impairment and dementia. The effects of WMH on response to cognitive training interventions are relatively unknown. The current study assessed (a) proximal cognitive training performance following a 3-month randomized control trial and (b) the contribution of baseline whole-brain WMH load, defined as total lesion volume (TLV), on pre-post proximal training change.
Participants and Methods:
Sixty-two healthy older adults ages 65-84 completed either adaptive cognitive training (CT; n=31) or educational training control (ET; n=31) interventions. Participants assigned to CT completed 20 hours of attention/processing speed training and 20 hours of working memory training delivered through commercially-available Posit Science BrainHQ. ET participants completed 40 hours of educational videos. All participants also underwent sham or active transcranial direct current stimulation (tDCS) as an adjunctive intervention, although not a variable of interest in the current study. Multimodal MRI scans were acquired during the baseline visit. T1- and T2-weighted FLAIR images were processed using the Lesion Segmentation Tool (LST) for SPM12. The Lesion Prediction Algorithm of LST automatically segmented brain tissue and calculated lesion maps. A lesion threshold of 0.30 was applied to calculate TLV. A log transformation was applied to TLV to normalize the distribution of WMH. Repeated-measures analysis of covariance (RM-ANCOVA) assessed pre/post change in proximal composite (Total Training Composite) and sub-composite (Processing Speed Training Composite, Working Memory Training Composite) measures in the CT group compared to their ET counterparts, controlling for age, sex, years of education and tDCS group. Linear regression assessed the effect of TLV on post-intervention proximal composite and sub-composite, controlling for baseline performance, intervention assignment, age, sex, years of education, multisite scanner differences, estimated total intracranial volume, and binarized cardiovascular disease risk.
Results:
RM-ANCOVA revealed two-way group*time interactions such that those assigned cognitive training demonstrated greater improvement on proximal composite (Total Training Composite) and sub-composite (Processing Speed Training Composite, Working Memory Training Composite) measures compared to their ET counterparts. Multiple linear regression showed higher baseline TLV associated with lower pre-post change on Processing Speed Training sub-composite (ß = -0.19, p = 0.04) but not other composite measures.
Conclusions:
These findings demonstrate the utility of cognitive training for improving postintervention proximal performance in older adults. Additionally, pre-post proximal processing speed training change appear to be particularly sensitive to white matter hyperintensity load versus working memory training change. These data suggest that TLV may serve as an important factor for consideration when planning processing speed-based cognitive training interventions for remediation of cognitive decline in older adults.
We present seismic measurements of the firn column at Korff Ice Rise, West Antarctica, including measurements of compressional-wave velocity and attenuation. We describe a modified spectral-ratio method of measuring the seismic quality factor (Q) based on analysis of diving waves, which, combined with a stochastic method of error propagation, enables us to characterise the attenuative structure of firn in greater detail than has previously been possible. Q increases from 56 ± 23 in the uppermost 12 m to 570 ± 450 between 55 and 77 m depth. We corroborate our method with consistent measurements obtained via primary reflection, multiple, source ghost, and critically refracted waves. Using the primary reflection and its ghost, we find Q = 53 ± 20 in the uppermost 20 m of firn. From the critical refraction, we find Q = 640 ± 400 at 90 m depth. Our method aids the understanding of the seismic structure of firn and benefits characterisation of deeper glaciological targets, providing an alternative means of correcting seismic reflection amplitudes in cases where conventional methods of Q correction may be impossible.
The world is astoundingly variable, and organisms – from individuals to whole communities – must respond to variability to survive. One example of nature’s variability is the fluctuations in populations of spruce budworm, Choristoneura fumiferana Clemens (Lepidoptera: Tortricidae), which cycle every 35 years. In this study, we examined how a parasitoid community altered its parasitism of budworm and other caterpillar species in response to these fluctuations. Budworm and other caterpillar species were sampled from balsam fir (Pinaceae) in three plots for 14 years in Atlantic Canada, then were reared to identify any emerging parasitoids. We found that the parasitoid community generally showed an indiscriminate response (i.e., no preference, where frequencies dictated parasitism rates) to changes in budworm frequencies relative to other caterpillar species on balsam fir. We also observed changes in topology and distributions of interaction strengths between the parasitoids, budworm, and other caterpillar species as budworm frequencies fluctuated. Our study contributes to the hypothesis that hardwood trees are a critical part of the budworm–parasitoid food web, where parasitoids attack other caterpillar species on hardwood trees when budworm populations are low. Taken together, our results show that a parasitoid community collectively alters species interactions in response to variable budworm frequencies, thereby fundamentally shifting food-web pathways.
The COVID-19 pandemic and mitigation measures are likely to have a marked effect on mental health. It is important to use longitudinal data to improve inferences.
Aims
To quantify the prevalence of depression, anxiety and mental well-being before and during the COVID-19 pandemic. Also, to identify groups at risk of depression and/or anxiety during the pandemic.
Method
Data were from the Avon Longitudinal Study of Parents and Children (ALSPAC) index generation (n = 2850, mean age 28 years) and parent generation (n = 3720, mean age 59 years), and Generation Scotland (n = 4233, mean age 59 years). Depression was measured with the Short Mood and Feelings Questionnaire in ALSPAC and the Patient Health Questionnaire-9 in Generation Scotland. Anxiety and mental well-being were measured with the Generalised Anxiety Disorder Assessment-7 and the Short Warwick Edinburgh Mental Wellbeing Scale.
Results
Depression during the pandemic was similar to pre-pandemic levels in the ALSPAC index generation, but those experiencing anxiety had almost doubled, at 24% (95% CI 23–26%) compared with a pre-pandemic level of 13% (95% CI 12–14%). In both studies, anxiety and depression during the pandemic was greater in younger members, women, those with pre-existing mental/physical health conditions and individuals in socioeconomic adversity, even when controlling for pre-pandemic anxiety and depression.
Conclusions
These results provide evidence for increased anxiety in young people that is coincident with the pandemic. Specific groups are at elevated risk of depression and anxiety during the COVID-19 pandemic. This is important for planning current mental health provisions and for long-term impact beyond this pandemic.
Head impact exposure (HIE) in youth football is a public health concern. The objective of this study was to determine if one season of HIE in youth football was related to cognitive changes.
Method:
Over 200 participants (ages 9–13) wore instrumented helmets for practices and games to measure the amount of HIE sustained over one season. Pre- and post-season neuropsychological tests were completed. Test score changes were calculated adjusting for practice effects and regression to the mean and used as the dependent variables. Regression models were calculated with HIE variables predicting neuropsychological test score changes.
Results:
For the full sample, a small effect was found with season average rotational values predicting changes in list-learning such that HIE was related to negative score change: standardized beta (β) = -.147, t(205) = -2.12, and p = .035. When analyzed by age clusters (9–10, 11–13) and adding participant weight to models, the R2 values increased. Splitting groups by weight (median split), found heavier members of the 9–10 cohort with significantly greater change than lighter members. Additionaly, significantly more participants had clinically meaningful negative changes: X2 = 10.343, p = .001.
Conclusion:
These findings suggest that in the 9–10 age cluster, the average seasonal level of HIE had inverse, negative relationships with cognitive change over one season that was not found in the older group. The mediation effects of age and weight have not been explored previously and appear to contribute to the effects of HIE on cognition in youth football players.
Spinal muscular atrophy (SMA) is a devastating rare disease that affects individuals regardless of ethnicity, gender, and age. The first-approved disease-modifying therapy for SMA, nusinursen, was approved by Health Canada, as well as by American and European regulatory agencies following positive clinical trial outcomes. The trials were conducted in a narrow pediatric population defined by age, severity, and genotype. Broad approval of therapy necessitates close follow-up of potential rare adverse events and effectiveness in the larger real-world population.
Methods:
The Canadian Neuromuscular Disease Registry (CNDR) undertook an iterative multi-stakeholder process to expand the existing SMA dataset to capture items relevant to patient outcomes in a post-marketing environment. The CNDR SMA expanded registry is a longitudinal, prospective, observational study of patients with SMA in Canada designed to evaluate the safety and effectiveness of novel therapies and provide practical information unattainable in trials.
Results:
The consensus expanded dataset includes items that address therapy effectiveness and safety and is collected in a multicenter, prospective, observational study, including SMA patients regardless of therapeutic status. The expanded dataset is aligned with global datasets to facilitate collaboration. Additionally, consensus dataset development aimed to standardize appropriate outcome measures across the network and broader Canadian community. Prospective outcome studies, data use, and analyses are independent of the funding partner.
Conclusion:
Prospective outcome data collected will provide results on safety and effectiveness in a post-therapy approval era. These data are essential to inform improvements in care and access to therapy for all SMA patients.
Icequakes at or near the bed of a glacier have the potential to allow us to investigate the interaction of ice with the underlying till or bedrock. Understanding this interaction is important for studying basal sliding of glaciers and ice streams, a critical process in ice dynamics models used to constrain future sea-level rise projections. However, seismic observations on glaciers can be dominated by seismic energy from surface crevassing. We present a method of automatically detecting basal icequakes and discriminating them from surface crevassing, comparing this method to a commonly used spectrum-based method of detecting icequakes. We use data from Skeidararjökull, an outlet glacier of the Vatnajökull Ice Cap, South-East Iceland, to demonstrate that our method outperforms the commonly used spectrum-based method. Our method detects a higher number of basal icequakes, has a lower rate of incorrectly identifying crevassing as basal icequakes and detects an additional, spatially independent basal icequake cluster. We also show independently that the icequakes do not originate from near the glacier surface. We conclude that the method described here is more effective than currently implemented methods for detecting and discriminating basal icequakes from surface crevassing.
BACTOT, Quebec’s healthcare-associated bloodstream infection (HABSI) surveillance program has been operating since 2007. In this study, we evaluated the changes in HABSI rates across 10 years of BACTOT surveillance under a Bayesian framework.
Design:
A retrospective, cohort study of eligible hospitals having participated in BACTOT for at least 3 years, regardless of their entry date. Multilevel Poisson regressions were fitted independently for cases of HABSI, catheter-associated bloodstream infections (CA-BSIs), non–catheter-associated primary BSIs (NCA-BSIs), and BSIs secondary to urinary tract infections (BSI-UTIs) as the outcome and log of patient days as the offset. The log of the mean Poisson rate was decomposed as the sum of a surveillance year effect, period effect, and hospital effect. The main estimate of interest was the cohort-level rate in years 2–10 of surveillance relative to year 1.
Results:
Overall, 17,479 cases and 33,029,870 patient days were recorded for the cohort of 77 hospitals. The pooled 10-year HABSI rate was 5.20 per 10,000 patient days (95% CI, 5.12–5.28). For HABSI, CA-BSI, and BSI-UTI, there was no difference between the estimated posterior rates of years 2–10 compared to year 1. The posterior means of the NCA-BSI rate ratios increased from the seventh year until the tenth year, when the rate was 29% (95% confidence interval, 1%–89%) higher than the first year rate.
Conclusions:
HABSI rates and those of the most frequent subtypes remained stable over the surveillance period. To achieve reductions in incidence, we recommend that more effort be expended in active interventions against HABSI alongside surveillance.
In 1969, Robert E. Gregg collected five species of ants (Hymenoptera: Formicidae) in three Subarctic localities near the town of Churchill, Manitoba, Canada, which he documented in a 1972 publication in The Canadian Entomologist. To determine whether there have been any additions to the local fauna – as might be predicted to occur in response to a warming climate and increased traffic to the Port of Churchill in the intervening 40 years – we re-collected ants from the same localities in 2012. We identified the ants we collected from Gregg’s sampling sites using both traditional morphological preparations and DNA barcoding. In addition, we examined specimens from Gregg’s initial collection that are accessioned at the Field Museum of Natural History (Chicago, Illinois, United States of America). Using this integrative approach we report seven species present at the same sites Gregg sampled 40 years earlier. We conclude that the apparent increase is likely not due to any arrivals from more southerly distributed ants, but to the increased resolution provided by DNA barcodes to resident species complexes with a complicated history. We provide a brief synopsis of these results and their taxonomic context.
Many Neotropical species whose range is restricted to tropical montane cloud forests (TMCF) are in danger of local or total extinction due to warming and drying as air warmed by climate change ascends these mountains. While the species richness of many arthropod higher taxa declines at high elevations, those species that do reside in TMCF are often highly specialised and endemic, rendering their natural history especially interesting. However, we know little about these TMCF arthropods. One genus of ants, Adelomyrmex Emery, 1897 (Hymenoptera: Formicidae), is characteristic of many TMCFs in Central America, and exemplifies this pattern. While workers of this genus are very common in leaf litter samples, winged males and winged queens have been unknown and nests have never been observed for most species. Here we report how a combination of affordable digital field microscopes and DNA barcoding has allowed nest discovery and documentation and linked male and worker Adelomyrmex. Based on this work, we have now learned that male Adelomyrmex can be quite abundant locally.
Here we report the first North American detection of the gall wasp Aulacidea pilosellae Kieffer (Hymenoptera: Cynipidae), native to Central Europe and a promising candidate biological control agent for invasive hawkweeds (Pilosella Vaillant, Asteraceae) in North America. This occurrence was discovered through the intersection of (i) publically available DNA barcode data and (ii) DNA sequencing of a biocontrol agent before its release. COI DNA sequences of A. pilosellae collected in Central Europe were compared with publically available DNA sequence records. Despite the presence of other Aulacidea Ashmead in the database, the most similar sequence to the European A. pilosellae was an as yet unidentified specimen collected in the Ottawa Valley of eastern Ontario, Canada. Subsequent sequencing of a second gene region (28S-D2) of the Ottawa Valley specimen yielded an identical DNA sequence to the European A. pilosellae, confirming the presence of this species in Ontario. This note highlights the potential synergy that can result from making DNA barcode data publically available before formal taxonomic identification, and a new benefit of incorporating DNA sequencing of standardised markers into biological control programmes.
A dead lyside sulphur (Kricogonia lyside (Godart, 1819): Lepidoptera: Pieridae) was found in Guelph, Ontario, Canada, on 4 April 2011. DNA barcode analysis indicates it likely originated in Texas, United States of America or northern Mexico. The occurrence of this specimen coincided with a very strong weather system extending from southern Texas into eastern Canada on 3–4 April 2011. All possible means of it reaching Ontario are unlikely: natural dispersal, natural transportation on the jet stream, transportation on a vehicle, importation of a pupa on produce, and direct human transport. Unfortunately, there was no way to differentiate between these possibilities.
ZnO nanowire (NW) arrays were examined with Transmission Electron Microscopy (TEM) in cross-section after preparation by Focused Ion Beam (FIB) milling. This technique revealed that ZnO nanowires grown using a Au catalyzed vapor technique typically have Au particles at the NW tips, and also randomly dispersed across the base crystal growth that joins adjacent NWs. It is shown the adjacent NWs and the combined base growth is one crystal structure which can be used as a back electrical contact making fabrication of vertical array devices possible. However, the base growth displays detrimental features such as embedded Au particles and lattice defects which can affect the electrical output through depletion regions and scattering centers. In an effort to overcome these problems we investigate a growth method that is nucleated through a minor alteration of the a-plane sapphire surface roughness via a weak chemical etch. Observations of various stages of the growth show the growth nucleates as separate nanoislands that grow in c-plane alignment with Sapphire (1-210), and as growth continues these islands meet and form a polycrystalline film. Further growth initiates nanowire growth and the formation of a single crystal base layer and NW structure that can cover several square millimeter’s. This allows high quality arrays that are relatively free from defects to be formed without any metals contamination and ready for further device processing.
Edited by
Alex S. Evers, Washington University School of Medicine, St Louis,Mervyn Maze, University of California, San Francisco,Evan D. Kharasch, Washington University School of Medicine, St Louis