Climate warming has direct and indirect effects on microbes associated with carbon cycling in northern lakes.

Northern lakes disproportionately influence the global carbon cycle, and may do so more in the future depending on how their microbial communities respond to climate warming. Microbial communities can change because of the direct effects of climate warming on their metabolism and the indirect effects of climate warming on groundwater connectivity from thawing of surrounding permafrost, especially at lower landscape positions. Here we used shotgun metagenomics to compare the taxonomic and functional gene composition of sediment microbes in 19 peatland lakes across a 1600-km permafrost transect in boreal western Canada. We found microbes responded differently to the loss of regional permafrost cover than to increases in local groundwater connectivity. These results suggest that both the direct and indirect effects of climate warming, which were respectively associated with loss of permafrost and subsequent changes in groundwater connectivity interact to change microbial composition and function. Archaeal methanogens and genes involved in all major methanogenesis pathways were more abundant in warmer regions with less permafrost, but higher groundwater connectivity partly offset these effects. Bacterial community composition and methanotrophy genes did not vary with regional permafrost cover, and the latter changed similarly to methanogenesis with groundwater connectivity. Finally, we found an increase in sugar utilization genes in regions with less permafrost, which may further fuel methanogenesis. These results provide the microbial mechanism for observed increases in methane emissions associated with loss of permafrost cover in this region and suggest that future emissions will primarily be controlled by archaeal methanogens over methanotrophic bacteria as northern lakes warm. Our study more generally suggests that future predictions of aquatic carbon cycling will be improved by considering how climate warming exerts both direct effects associated with regional-scale permafrost thaw and indirect effects associated with local hydrology.

Direct and Indirect Associations of Widespread Individual Differences in Brain White Matter Microstructure With Executive Functioning and General and Specific Dimensions of Psychopathology in Children.

BACKGROUND: Executive functions (EFs) are important partly because they are associated with risk for psychopathology and substance use problems. Because EFs have been linked to white matter microstructure, we tested the prediction that fractional anisotropy (FA) and mean diffusivity (MD) in white matter tracts are associated with EFs and dimensions of psychopathology in children younger than the age of widespread psychoactive substance use. METHODS: Parent symptom ratings, EF test scores, and diffusion tensor parameters from 8588 9- to 10-year-olds in the ABCD Study (Adolescent Brain Cognitive Development Study) were used. RESULTS: A latent factor derived from EF test scores was significantly associated with specific conduct problems and attention-deficit/hyperactivity disorder problems, with dimensions defined in a bifactor model. Furthermore, EFs were associated with FA and MD in 16 of 17 bilateral white matter tracts (range: ß = .05; SE = .17; through ß = -.31; SE = .06). Neither FA nor MD was directly associated with psychopathology, but there were significant indirect associations via EFs of both FA (range: ß = .01; SE = .01; through ß = -.09; SE = .02) and MD (range: ß = .01; SE = .01; through ß = .09; SE = .02) with both specific conduct problems and attention-deficit/hyperactivity disorder in all tracts except the forceps minor. CONCLUSIONS: EFs in children are inversely associated with diffusion tensor imaging measures in nearly all tracts throughout the brain. Furthermore, variance in diffusion tensor measures that is shared with EFs is indirectly shared with attention-deficit/hyperactivity disorder and conduct problems.

Impaired Spatial Reorientation in the 3xTg-AD Mouse Model of Alzheimer's Disease.

In early Alzheimer's disease (AD) spatial navigation is impaired; however, the precise cause of this impairment is unclear. Recent evidence suggests that getting lost is one of the first impairments to emerge in AD. It is possible that getting lost represents a failure to use distal cues to get oriented in space. Therefore, we set out to look for impaired use of distal cues for spatial orientation in a mouse model of amyloidosis (3xTg-AD). To do this, we trained mice to shuttle to the end of a track and back to an enclosed start box to receive a water reward. Then, mice were trained to stop in an unmarked reward zone to receive a brain stimulation reward. The time required to remain in the zone for a reward was increased across training, and the track was positioned in a random start location for each trial. We found that 6-month female, but not 3-month female, 6-month male, or 12-month male, 3xTg-AD mice were impaired. 6-month male and female mice had only intracellular pathology and male mice had less pathology, particularly in the dorsal hippocampus. Thus, AD may cause spatial disorientation as a result of impaired use of landmarks.

Effects of a Brief Physical Activity Program on Young Students' Physical Fitness.

BACKGROUND: Our objective was to test whether brief daily activity could increase young students' physical fitness and compare different forms of intervention delivery. METHODS: Two intervention groups were instructed to increase children's activity by 6 minutes daily. The principal was responsible for the intervention in the first group while classroom teachers were responsible in the second. The third group was a control. Success was defined by changes in student fitness. RESULTS: The principal-led group had a significant increase in the number of 75-foot laps completed after intervention (+0.61 laps) and a significant decrease in after-exercise heart rate (-37.4 beats per minute) as compared with the control group. The teacher-led group experienced no change in either outcome. CONCLUSIONS: Our findings demonstrate that a 6-minute increase in activity can produce a significant improvement in student fitness. Administrative support of school-based interventions can have a positive impact on program completion.

The availability, spatial accessibility, service utilisation and retrieval cost of paediatric intensive care services for children in rural, regional and remote Queensland: study protocol.

BACKGROUND: Specialist health services are often organised on a regionalised basis whereby clinical resources and expertise are concentrated in areas of high population. Through a high volume caseload, regionalised facilities may provide improved clinical outcomes for patients. In some cases, regionalisation may be the only economically viable way to organise specialist care. While regionalisation may have benefits, it may also disadvantage some population groups, particularly in circumstances where distance and time are impediments to access.Queensland is a large Australian state with a distributed population. Providing equitable access to specialist healthcare services to the population is challenging. Specialist care for critically ill or injured children is provided by the Queensland Paediatric Intensive Care Service which comprises two tertiary paediatric intensive care units. The two units are located 6 km (3.7 miles) apart by road in the state capital of Brisbane and provide state-wide telephone advice and specialist retrieval services. Services also extend into the northern area of the adjacent state of New South Wales. In some cases children may be managed locally in adult intensive care units in regional hospitals.The aim of this study is to describe the effect of geography and service organisation for children who need intensive care services but who present outside of metropolitan centres in Queensland. METHODS/DESIGN: Using health services and population data, the availability and spatial accessibility to paediatric intensive care services will be analysed. Retrieval utilisation and the associated costs to the health service will be analysed to provide an indication of service utilisation by non-metropolitan patients. DISCUSSION: While the regionalisation or centralisation of specialist services is recognised as an economical way to provide specialist health services, the extent to which these models serve critically ill children who live some distance from tertiary care has not been described. This study will provide new information on the effect of the regionalisation of specialist healthcare for critically ill children in Queensland and will have relevance to other regionalised health services. This study, which is focussed on describing the organisation, supply and demands on the health service, will provide the foundation for future work to explore clinical outcomes for non-metropolitan children who require intensive care.