Canadian permafrost stores large pools of ammonium and optically distinct dissolved organic matter.

Permafrost degradation may lead to mobilization of carbon and nutrients and enhance microbial processing rates of previously frozen organic matter. Although the pool size and chemical composition of dissolved organic matter (DOM) are fundamental determinants of the carbon cycle in Arctic watersheds, its source within the seasonally thawing active layer and the underlying permafrost remains largely uncharacterized. Here, we used 25 soil cores that extended down into the permafrost from nine sites across Arctic Canada to quantify dissolved organic carbon (DOC) and nitrogen stocks, and to characterize DOM optical properties. Organic permafrost stores 5-7 times more DOC and ammonium than the active layer and mineral permafrost. Furthermore, the permafrost layers contain substantial low molecular weight DOM with low aromaticity suggesting high biodegradability. We conclude that soil organic matter stoichiometry and cryogenic processes determine permafrost DOM chemistry, and that thawing will mobilize large amounts of labile DOC and ammonium into Arctic watersheds.

Global plant trait relationships extend to the climatic extremes of the tundra biome.

The majority of variation in six traits critical to the growth, survival and reproduction of plant species is thought to be organised along just two dimensions, corresponding to strategies of plant size and resource acquisition. However, it is unknown whether global plant trait relationships extend to climatic extremes, and if these interspecific relationships are confounded by trait variation within species. We test whether trait relationships extend to the cold extremes of life on Earth using the largest database of tundra plant traits yet compiled. We show that tundra plants demonstrate remarkably similar resource economic traits, but not size traits, compared to global distributions, and exhibit the same two dimensions of trait variation. Three quarters of trait variation occurs among species, mirroring global estimates of interspecific trait variation. Plant trait relationships are thus generalizable to the edge of global trait-space, informing prediction of plant community change in a warming world.

Evaluating health benefits and cost-effectiveness of a mass-media campaign for improving participation in the National Bowel Cancer Screening Program in Australia.

OBJECTIVES: The Australian National Bowel Cancer Screening Program (NBCSP) offers free 2-yearly immunochemical faecal occult blood testing to individuals aged 50-74 years; national participation in 2015-2016 was 41%. In 2017, a 7-week television-led mass-media campaign to increase participation in the Australian state of Victoria was associated with a 1.31-fold increase in participation for 11 weeks. We aimed to evaluate the cost-effectiveness and health benefits of the 2017 campaign and scaled-up equivalent campaigns run over 4 years in Victoria and nationally. STUDY DESIGN: This study used microsimulation modelling. METHODS: A comprehensive microsimulation model of colorectal cancer (CRC), Policy1-Bowel, was used to simulate three scenarios. Scenario 1 simulated the 2017 campaign in Victoria; Scenarios 2 and 3 assumed that campaigns were run three times annually from 2019 to 2022 in Victoria and Australia-wide, respectively. Total campaign costs of AUD$1million, AUD$10million, and AUD$40million were assumed for Scenarios 1, 2, and 3, respectively. The incremental effects and costs of the campaign on the NBCSP were assessed. A governmental perspective was used. RESULTS: All campaign scenarios were predicted to be highly cost-effective, with cost-effectiveness ratios under AUD$4,800/life-year saved. The actual 2017 campaign in Victoria is estimated to prevent 319 CRC cases and 183 deaths over the following 40 years. A 4-year campaign would prevent 1,750 CRC cases and 987 deaths if conducted in Victoria, and 8,100 cases and 4,330 deaths if conducted Australia-wide. CONCLUSION: Mass-media participation campaigns could be highly cost-effective and maximise the potential life-saving impact of bowel screening. These results support ongoing investment in major bowel screening campaigns.

Cancer costs and gender: a snapshot of issues, trends, and opportunities to reduce inequities using Australia as an example.

As the cancer burden increases, so too does the cost, to health systems, economies, and individuals. There is increasing interest in productivity and out-of-pocket costs for individuals and their carers, but these remain poorly understood. The costs of cancer in women, often carers themselves, are less understood. This summary analysis explored data on the cancer burden in Australia (and health costs in comparable countries), including expenditure reports and literature on macroeconomic outcomes and out-of-pocket costs, to highlight the cost impacts of a cancer diagnosis in women, at a societal and an individual level. Data on productivity costs were skewed toward men, as men are over-represented in paid work compared with women. Data on societal and individual costs of cancer in women were scant, yet the predominance of women in unpaid work suggests the cost is significant. Evidence for the benefits of cancer prevention and early detection suggests that improved targeting of interventions to women would reduce costs at a societal and an individual level. More research is needed on the specific impacts of cancer on women and those they care for, to better target public health and support services to need.

Traditional plant functional groups explain variation in economic but not size-related traits across the tundra biome.

AIM: Plant functional groups are widely used in community ecology and earth system modelling to describe trait variation within and across plant communities. However, this approach rests on the assumption that functional groups explain a large proportion of trait variation among species. We test whether four commonly used plant functional groups represent variation in six ecologically important plant traits. LOCATION: Tundra biome. TIME PERIOD: Data collected between 1964 and 2016. MAJOR TAXA STUDIED: 295 tundra vascular plant species. METHODS: We compiled a database of six plant traits (plant height, leaf area, specific leaf area, leaf dry matter content, leaf nitrogen, seed mass) for tundra species. We examined the variation in species-level trait expression explained by four traditional functional groups (evergreen shrubs, deciduous shrubs, graminoids, forbs), and whether variation explained was dependent upon the traits included in analysis. We further compared the explanatory power and species composition of functional groups to alternative classifications generated using post hoc clustering of species-level traits. RESULTS: Traditional functional groups explained significant differences in trait expression, particularly amongst traits associated with resource economics, which were consistent across sites and at the biome scale. However, functional groups explained 19% of overall trait variation and poorly represented differences in traits associated with plant size. Post hoc classification of species did not correspond well with traditional functional groups, and explained twice as much variation in species-level trait expression. MAIN CONCLUSIONS: Traditional functional groups only coarsely represent variation in well-measured traits within tundra plant communities, and better explain resource economic traits than size-related traits. We recommend caution when using functional group approaches to predict tundra vegetation change, or ecosystem functions relating to plant size, such as albedo or carbon storage. We argue that alternative classifications or direct use of specific plant traits could provide new insights for ecological prediction and modelling.

Myopathy with skeletal asymmetry and hemidiaphragm elevation is caused by myotubularin mutations.

The authors report two families with a myopathy phenotype affecting only women, marked by asymmetric weakness, skeletal asymmetry, and an elevated hemidiaphragm. One family had a mutation in a stop codon in exon 9 of the myotubularin gene, and the other had a splice site mutation in exon 13. Both families had manifesting and nonmanifesting carriers. Skewed X-inactivation appeared to explain the clinical manifestations in only one of the two families.

Practice parameter: Steroids, acyclovir, and surgery for Bell's palsy (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology.

OBJECTIVE: To determine the effectiveness of steroids, acyclovir, and surgical facial nerve decompression in Bell's palsy. METHODS: The authors identified articles by searching MEDLINE and selected those that prospectively compared outcomes in patients treated with steroids, acyclovir, or surgery with patients not receiving these modalities. The authors graded the quality of each study (class I to IV) using a standard classification-of-evidence scheme. They compared the proportion of patients recovering facial function in the treated group to the proportion of patients recovering facial function in the control group. RESULTS: The authors identified no adequately powered class I studies for any treatment modality. The pooled results of two class I and two class II studies showed significantly better facial outcomes in steroid-treated patients compared with non-steroid-treated patients (relative rate good outcome 1.16, 95% CI 1.05 to 1.29). One class II study demonstrated a significant benefit from acyclovir in combination with prednisone compared with prednisone alone (relative rate good outcome 1.22, 95% CI 1.02 to 1.45). All studies describing outcomes in patients treated with facial nerve decompression were graded as class IV. CONCLUSION: For patients with Bell's palsy, a benefit from steroids, acyclovir, or facial nerve decompression has not been definitively established. However, available evidence suggests that steroids are probably effective and acyclovir (combined with prednisone) is possibly effective in improving facial functional outcomes. There is insufficient evidence to make recommendations regarding surgical facial nerve decompression for Bell's palsy. Well-designed studies of the effectiveness of treatments for Bell's palsy are still needed.

Fire effects on ecosystem nitrogen cycling in a Californian bishop pine forest.

Fire can cause severe nitrogen (N) losses from grassland, chaparral, and temperate and boreal forest ecosystems. Paradoxically, soil ammonium levels are markedly increased by fire, resulting in high rates of primary production in re-establishing plant communities. In a manipulative experiment, we examined the influence of wild-fire ash residues on soil, microbial and plant N pools in a recently burned Californian bishop pine (Pinus muricata D. Don) forest. Ash stimulated post-fire primary production and ecosystem N retention through direct N inputs from ash to soils, as well as indirect ash effects on soil N availability to plants. These results suggest that redistribution of surface ash after fire by wind or water may cause substantial heterogeneity in soil N availability to plants, and could be an important mechanism contributing to vegetation patchiness in fire-prone ecosystems. In addition, we investigated the impact of fire on ecosystem N cycling by comparing 15N natural abundance values from recently burned and nearby unburned P. muricata forest communities. At the burned site, 15N natural abundance in recolonising species was similar to that in bulk soil organic matter. By contrast, there was a marked 15N depletion in the same species relative to the total soil N pool at the unburned site. These results suggest that plant uptake of nitrate (which tends to be strongly depleted in 15N because of fractionation during nitrification) is low in recently burned forest communities but could be an important component of eco- system N cycling in mature conifer stands.

Initial effects of experimental warming on above- and belowground components of net ecosystem CO2 exchange in arctic tundra.

The Arctic contains extensive soil carbon reserves that could provide a substantial positive feedback to atmospheric CO2 concentrations and global warming. Evaluation of this hypothesis requires a mechanistic understanding of the in situ responses of individual components of tundra net ecosystem CO2 exchange (NEE) to warming. In this study, we measured NEE, total ecosystem respiration and respiration from below ground in experimentally warmed plots within Alaskan acidic tussock tundra. Soil warming of 2-4°C during a single growing season caused strong increases in total ecosystem respiration and belowground respiration from moss-dominated inter-tussock areas, and similar trends from sedge-dominated tussocks. Consequently, the overall effect of the manipulation was to substantially enhance net ecosystem carbon loss during mid-summer. Components of vascular plant biomass were closely correlated with total ecosystem respiration and belowground respiration in control plots of both microsites, but not in warmed plots. By contrast, in the warmed inter-tussock areas, belowground respiration was most closely correlated with organic-layer depth. Warming in tussock areas was associated with increased leaf nutrient pools, indicating enhanced rates of soil nutrient mineralisation. Together, these results suggest that warming enhanced net ecosystem CO2 efflux primarily by stimulating decomposition of soil organic matter, rather than by increasing plant-associated respiration. Our short-term experiment provides field evidence to support previous growth chamber and modelling studies indicating that arctic soil C reserves are relatively sensitive to warming and could supply an initial positive feedback to rising atmospheric CO2 concentrations/changing climate.