Changes in Soil Fungal Communities, Extracellular Enzyme Activities, and Litter Decomposition Across a Fire Chronosequence in Alaskan Boreal Forests

Wildfires are a pervasive disturbance in boreal forests, and the frequency and intensity of boreal wildfires is expected to increase with climate warming. Boreal forests store a large fraction of global soil organic carbon (C), but relatively few studies have documented how wildfires affect soil microbial communities and soil C dynamics. We used a fire chronosequence in upland boreal forests of interior Alaska with sites that were 1, 7, 12, 24, 55, ~90, and ~100 years post-fire to examine the short- and long-term responses of fungal community composition, fungal abundance, extracellular enzyme activity, and litter decomposition to wildfires. We hypothesized that post-fire changes in fungal abundance and community composition would constrain decomposition following fires. We found that wildfires altered the composition of soil fungal communities. The relative abundance of ascomycetes significantly increased following fire whereas basidiomycetes decreased. Post-fire decreases in basidiomycete fungi were likely attributable to declines in ectomycorrhizal fungi. Fungal hyphal lengths in the organic horizon significantly declined in response to wildfire, and they required at least 24 years to return to pre-fire levels. Post-fire reductions in fungal hyphal length were associated with decreased activities of hydrolytic extracellular enzymes. In support of our hypothesis, the decomposition rate of aspen and black spruce litter significantly increased as forests recovered from fire. Our results indicate that post-fire reductions in soil fungal abundance and activity likely inhibit litter decomposition following boreal wildfires. Slower rates of litter decay may lead to decreased heterotrophic respiration from soil following fires and contribute to a negative feedback to climate warming

The Digital Engagement of Older People:Systematic Scoping Review Protocol

BACKGROUND: There is an ongoing negative narrative about aging that portrays older people as a socioeconomic burden on society. However, increased longevity and good health will allow older adults to contribute meaningfully to society and maximize their well-being. As such, a paradigm shift toward healthy and successful aging can be potentially facilitated by the growing digital technology use for mainstream (day-to-day activities) and assisted living (health and social care). Despite the rising digital engagement trend, digital inequality between the age groups persists. OBJECTIVE: The aims of this scoping review are to identify the extent and breadth of existing literature of older people’s perspectives on digital engagement and summarize the barriers and facilitators for technological nonuse, initial adoption, and sustained digital technology engagement. METHODS: This review will be based on the Arksey and O’Malley framework for scoping reviews. The 6-stage framework includes: identifying research questions, identifying relevant studies, study selection, charting the data, summarizing and reporting the results, and a consultation exercise. Published literature will be searched on primary electronic databases such as the Association of Computing Machinery, Web of Science, MEDLINE, PsycINFO, CINAHL, and ScienceDirect. Common grey literature sources will complement the database search on the topic. A two-stage (title/abstract and full article) screening will be conducted to obtain eligible studies for final inclusion. A standardized data extraction tool will be used to extract variables such as the profile of the study population, technologies under investigation, stage of digital engagement, and the barriers and facilitators. Identified and eligible studies will be analyzed using a quantitative (ie, frequency analysis) and qualitative (ie, content analysis) approach suitable for comparing and evaluating literature to provide an evaluation of the current state of the older person’s digital engagement. Inclusion will be based on the Joanna Briggs Institute–recommended participant, concept, and context framework. Articles on older people (65 years and older), on digital technology engagement, and from a global context will be included in our review. RESULTS: The results of this review are expected in July 2021. CONCLUSIONS: The findings from this review will identify the extent and nature of empirical evidence on how older people digitally engage and the associated barriers and facilitators. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): PRR1-10.2196/2561

Genetic Variation and Population Substructure in Outbred CD-1 Mice: Implications for Genome-Wide Association Studies

Outbred laboratory mouse populations are widely used in biomedical research. Since little is known about the degree of genetic variation present in these populations, they are not widely used for genetic studies. Commercially available outbred CD-1 mice are drawn from an extremely large breeding population that has accumulated many recombination events, which is desirable for genome-wide association studies. We therefore examined the degree of genome-wide variation within CD-1 mice to investigate their suitability for genetic studies. The CD-1 mouse genome displays patterns of linkage disequilibrium and heterogeneity similar to wild-caught mice. Population substructure and phenotypic differences were observed among CD-1 mice obtained from different breeding facilities. Differences in genetic variation among CD-1 mice from distinct facilities were similar to genetic differences detected between closely related human populations, consistent with a founder effect. This first large-scale genetic analysis of the outbred CD-1 mouse strain provides important considerations for the design and analysis of genetic studies in CD-1 mice.</p

Effects of the colour of photophase light on locomotor activity in a nocturnal and a diurnal South African rodent

Many physiological and behavioural responses to varying qualities of light, particularly during the night (scotophase), have been well documented in rodents. We used varying wavelengths of day-time (photophase) lighting to assess daily responses in locomotor activity in the nocturnal Namaqua rock mouse (Micaelamys namaquensis) and diurnal four-striped field mouse (Rhabdomys pumilio). Animals were exposed to three light–dark cycle regimes: a short-wavelength- (SWLC, blue), a medium-wavelength- (MWLC, green) and a long-wavelength light–dark cycle (LWLC, red). Overall, daily locomotor activity of both species changed according to different wavelengths of light: the diurnal species displayed most activity under the SWLC and the nocturnal species exhibited the highest levels of activity under the LWLC. Both species showed an increase in diurnal activity and a decrease in nocturnal activity under the LWLC. These results indicate an attenuated responsiveness to long-wavelength light in the nocturnal species, but this does not appear to be true for the diurnal species. These results emphasize that the effect of light on the locomotor activity of animals depends on both the properties of the light and the temporal organization of activity of a species.http://rsbl.royalsocietypublishinghj2019Mammal Research InstituteZoology and Entomolog

The Evolving Demographic and Health Transition in Four Low- and Middle-Income Countries: Evidence from Four Sites in the INDEPTH Network of Longitudinal Health and Demographic Surveillance Systems.

This paper contributes evidence documenting the continued decline in all-cause mortality and changes in the cause of death distribution over time in four developing country populations in Africa and Asia. We present levels and trends in age-specific mortality (all-cause and cause-specific) from four demographic surveillance sites: Agincourt (South Africa), Navrongo (Ghana) in Africa; Filabavi (Vietnam), Matlab (Bangladesh) in Asia. We model mortality using discrete time event history analysis. This study illustrates how data from INDEPTH Network centers can provide a comparative, longitudinal examination of mortality patterns and the epidemiological transition. Health care systems need to be reconfigured to deal simultaneously with continuing challenges of communicable disease and increasing incidence of non-communicable diseases that require long-term care. In populations with endemic HIV, long-term care of HIV patients on ART will add to the chronic care needs of the community

Locomotor activity in the Namaqua rock mouse (Micaelamys namaquensis) : entrainment by light manipulations

The locomotor activity rhythms of wild-caught Namaqua rock mice (Micaelamys namaquensis (A. Smith, 1834)) were examined under four light-cycle regimes to quantitatively describe the daily expression of locomotor activity and to study the innate relationship between activity and the light–dark cycle. Activity was always significantly higher at night than during the day; we note four trends. (1) The LD1 light cycle (12 h light : 12 h dark) established a distinct light-entrained and strongly nocturnal activity rhythm (99.11% nocturnal activity). The activity onset was prompt (zeitgeber time (ZT) 12.2 ± 0.04) and activity continued without any prominent peaks or extended times of rest until the offset of activity at ZT 23.73 ± 0.08. (2) Evidence for the internal maintenance of locomotor activity was obtained from the constant dark cycle (DD) in which locomotor activity free ran (mean = 23.89 h) and 77.58% of the activity was expressed during the subjective night. (3) During re-entrainment (LD2; 12 h light : 12 h dark), a nocturnal activity rhythm was re-established (98.65% nocturnal activity). (4) The inversion of the light cycle (DL; 12 h dark : 12 h light) evoked a shift in activity that again revealed dark-induced locomotor activity (95.69% nocturnal activity). Females were consistently more active than males in all of the light cycles, but only under the DD and LD2 cycles were females significantly more active than males. Although this species is considered nocturnal from field observations, information regarding its daily expression of activity and the role of light in its entrainment is lacking. To the best of our knowledge, this study is the first to report quantitatively on the species’ daily rhythm of activity and to investigate its relationship to the light–dark cycle.Les rythmes de l’activité locomotrice de souris de Namaqua (Micaelamys namaquensis (A. Smith, 1834)) capturées a` l’état sauvage ont été examinés pour quatre régimes de cycle lumineux afin de décrire de manière quantitative l’expression journalière de l’activité locomotrice et d’étudier le lien inné entre l’activité et le cycle lumière–noirceur. L’activité était toujours significativement plus grande la nuit que le jour; quatre tendances ont été notées. (1) Le cycle lumineux LDI (12 h de lumière, 12 h de noirceur) a établi un rythme d’activité distinct entraîné par la lumière et fortement nocturne (activité a` 99,11 % nocturne). Le début de l’activité n’a pas tardé (temps de zeitgeber (ZT) 12,2 ± 0,04) et l’activité s’est poursuivie sans pointe proéminente ou longue période de repos jusqu’a` la fin de l’activité a` ZT 23,73 ± 0,08. (2) Des indications du maintien interne de l’activité locomotrice ont été obtenues du cycle de noirceur constante (DD) dans lequel l’activité locomotrice avait libre cours ( moyen = 23,89 h) et 77,58 % de l’activité s’exprimait durant la nuit subjective. (3) Durant le réentrainement (LD2; 12 h de lumière, 12 h de noirceur), un rythme d’activité nocturne s’est rétabli (activité a` 98,65 % nocturne). (4) L’inversion du cycle lumineux (DL; 12 h de noirceur, 12 h de lumière) a provoqué un changement de l’activité qui révélait encore une fois une activité locomotrice induite par la noirceur (activité a` 95,69 % nocturne). Les femelles étaient uniformément plus actives que les mâles pour tous les cycles lumineux, mais les cycles DD et LD2 étaient les seuls durant lesquels les femelles étaient significativement plus actives que les mâles. Bien que cette espèce soit considérée comme étant nocturne sur la base d’observations de terrain, de l’information concernant l’expression journalière de son activité et le rôle de la lumière dans l’entraînement de cette dernière fait défaut. À notre connaissance, cette étude est la première a` rendre compte de manière quantitative du rythme journalier de l’activité de cette espèce et a` examiner le lien de ce dernier avec le cycle lumière–noirceur.South African Research Chair of Mammal Behavioural Ecology and Physiology and University of Pretoria.http://www.nrcresearchpress.com/cjzhb201

Promoting neurological recovery of function via metaplasticity

The modification of synapses by neural activity has been proposed to be the substrate for experience-dependent brain development, learning, and recovery of visual function after brain injury. The effectiveness or ‘strength’ of synaptic transmission can be persistently modified in response to defined patterns of pre- and post-synaptic activity. Well-studied examples of this type of synaptic plasticity are long-term potentiation and long-term depression. Can we exploit the current understanding of these mechanisms in order to strengthen brain connections that may have been weakened or impaired by sensory deprivation, disease or injury? Theoretically motivated research in the visual cortex has suggested ways to promote synaptic potentiation. The theoretical concept is that the type and extent of synaptic plasticity caused by patterns of activity depend critically on the recent prior history of synaptic or cellular activity. Studies in visual cortex strongly support this concept, and have suggested a mechanism for ‘metaplasticity’ – the plasticity of synaptic plasticity – based on activity-dependent modification of NMDA-receptor structure and function. The knowledge gained by these studies suggests ways in which recovery of function can be promoted.National Institutes of Health (U.S.) (NIH/NEI Grant RO1 EYO12309

Promoting physical activity among cancer survivors: meta-analysis and meta-cart analysis of randomized controlled trials

Objective: We conducted a meta-analysis of physical activity interventions among cancer survivors in order to (a) quantify the magnitude of intervention effects on physical activity, and (b) determine what combination of intervention strategies maximizes behavior change. Methods: Out of 32,626 records that were located using computerized searches, 138 independent tests (N = 13,050) met the inclusion criteria for the review. We developed a bespoke taxonomy of 34 categories of techniques designed to promote psychological change, and categorized sample, intervention, and methodological characteristics. Random effects meta-analysis and meta-regressions were conducted; effect size data were also submitted to Meta-CART analysis. Results: The sample-weighted average effect size for physical activity interventions was d+ = .35, equivalent to an increase of 1,149 steps per day. Effect sizes exhibited both publication bias and small sample bias but remained significantly different from zero, albeit of smaller magnitude (d+ ≥ .20), after correction for bias. Meta-CART analysis indicated that the major difference in effectiveness was attributable to supervised versus unsupervised programs (d+ = .49 vs. .26). Greater contact time was associated with larger effects in supervised programs. For unsupervised programs, establishing outcome expectations, greater contact time, and targeting overweight or sedentary participants each predicted greater program effectiveness, whereas prompting barrier identification and providing workbooks were associated with smaller effect sizes. Conclusion: The present review indicates that interventions have a small but significant effect on physical activity among cancer survivors, and offers insights into how the effectiveness of future interventions might be improved