4,128 research outputs found
Can continental bogs with stand the pressure due to climate change?
Not all peatlands are alike. Theoretical and process based models suggest that ombrogenic, oligotrophic peatlands can withstand the pressures due to climate change because of the feedbacks among ecosystem production, decomposition and water storage. Although there have been many inductive explanations inferring from paleo-records, there is a lack of deductive empirical tests of the models predictions of these systemsâ stability and there are few records of the changes in the net ecosystem carbon balance (NECB) of peatlands that are long enough to examine the dynamics of the NECB in relation to climate variability. Continuous measurements of all the components of the NECB and the associated general climatic and environmental conditions have been made at the Mer Bleue (MB) peatland, a large, 28 km2, 5 m deep, raised ombro-oligotrophic, shrub and Sphagnum covered bog, near Ottawa, Canada from May 1, 1998 until the present. The sixteen-year daily CO2, CH4, and DOC flux and NECB covers a wide range of variability in peatland water storage from very dry to very wet growing seasons. We used the MB data to test the extent of MB peatlandâs stability and the strength of the underlying key feedback between the NECB and changes in water storage projected by the models. In 2007 we published a six-year (1999-2004) net ecosystem carbon balance (NECB) for MB of âŒ22 ± 40 g C m-2 yr-1, but we have since recalculated the 1998-2004 NECB to be 32 ± 40 g C m-2 yr-1 based on a reanalyzed average NEP of 51 ± 41 g C m-2 yr-1. Over the same period the net loss of C via the CH4 and DOC fluxes were -4 ± 1 and -15 ± 3 g C m-2 yr-1. The 1998-2004 six-year MB average NECB is similar to the long-term C accumulation rate, estimated from MB peat cores, for the last 3,000 years. The post 2004 MB NEP has increased to an average of âŒ96 ± 32 g C m-2 yr-1 largely to there being generally wetter growing seasons. The losses of C via DOC (18 ± 1 g C m-2 yr-1) and CH4 (7 ± 4 g C m-2 yr-1) while showing considerable year-to-year variability are not significantly different post 2004. Hence, the proportional loss of C as DOC and CH4 in the MB NECB is slightly less post-2004 than it was before 2004 though the cumulative errors preclude statistically differences. As a result the MB NECB has increased to 79 ± 29 g C m-2 yr-1 post 2004 yielding a 14 year contemporary NECB of 56 ± 36 g C m-2 yr-1, which is double the long-term accumulation rate of C. The variability in the annual NECB and growing season mean NEP for the MB bog can be explained (r2 = 0.35, p \u3c 0.01) by the variability in growing season water table depth. These results suggest the carbon balance â water table feedback is sufficient enough to create stability in continental bogs so they will withstand a considerable amount of climate change
Economic Evaluation Plan (EEP) for A Very Early Rehabilitation Trial (AVERT): An international trial to compare the costs and cost-effectiveness of commencing out of bed standing and walking training (very early mobilization) within 24 h of stroke onset with usual stroke unit care
Rationale: A key objective of A Very Early Rehabilitation Trial is to determine if the intervention, very early mobilisation following stroke, is cost-effective. Resource use data were collected to enable an economic evaluation to be undertaken and a plan for the main economic analyses was written prior to the completion of follow up data collection.
Aim and hypothesis To report methods used to collect resource use data, pre-specify the main economic evaluation analyses and report other intended exploratory analyses of resource use data.
Sample size estimates: Recruitment to the trial has been completed. A total of 2,104 participants from 56 stroke units across three geographic regions participated in the trial.
Methods and design: Resource use data were collected prospectively alongside the trial using standardised tools. The primary economic evaluation method is a cost-effectiveness analysis to compare resource use over 12 months with health outcomes of the intervention measured against a usual care comparator. A cost-utility analysis is also intended.
Study outcome: The primary outcome in the cost-effectiveness analysis will be favourable outcome (modified Rankin Scale score 0-2) at 12 months. Cost-utility analysis will use health-related quality of life, reported as quality-adjusted life years gained over a 12 month period, as measured by the modified Rankin Scale and the Assessment of Quality of Life.
Discussion: Outcomes of the economic evaluation analysis will inform the cost-effectiveness of very early mobilisation following stroke when compared to usual care. The exploratory analysis will report patterns of resource use in the first year following stroke
Comparative functional characterization of the CSR-1 22G-RNA pathway in Caenorhabditis nematodes
As a champion of small RNA research for two decades, Caenorhabditis elegans has revealed the essential Argonaute CSR-1 to play key nuclear roles in modulating chromatin, chromosome segregation and germline gene expression via 22G-small RNAs. Despite CSR-1 being preserved among diverse nematodes, the conservation and divergence in function of the targets of small RNA pathways remains poorly resolved. Here we apply comparative functional genomic analysis between C. elegans and Caenorhabditis briggsae to characterize the CSR-1 pathway, its targets and their evolution. C. briggsae CSR-1-associated small RNAs that we identified by immunoprecipitation-small RNA sequencing overlap with 22G-RNAs depleted in cbr-csr-1 RNAi-treated worms. By comparing 22G-RNAs and target genes between species, we defined a set of CSR-1 target genes with conserved germline expression, enrichment in operons and more slowly evolving coding sequences than other genes, along with a small group of evolutionarily labile targets. We demonstrate that the association of CSR-1 with chromatin is preserved, and show that depletion of cbr-csr-1 leads to chromosome segregation defects and embryonic lethality. This first comparative characterization of a small RNA pathway in Caenorhabditis establishes a conserved nuclear role for CSR-1 and highlights its key role in germline gene regulation across multiple animal species
SOMATOSENSORY AMPLIFICATION AND MENOPAUSAL SYMPTOMS IN BREAST CANCER SURVIVORS AND MIDLIFE WOMEN
OBJECTIVES
Somatosensory amplification is the experience of sensing everyday bodily sensations as intense, agitating, and unpleasant. Using data from menopausal breast cancer survivors and midlife women without cancer, the study purposes were to (1) explore the psychometric properties of the Somatosensory Amplification Scale and (2) to describe somatosensory amplification and its relationship to menopausal symptoms of hot flashes, mood and sleep disturbance.
STUDY DESIGN
This was a cross-sectional, descriptive, correlational study using demographic, e-diary, and questionnaire data from 99 breast cancer survivors and 138 midlife women.
MAIN OUTCOME MEASURES
Somatosensory amplification, hot flashes (frequency, severity, bother, interference, perceived control), mood, and sleep.
RESULTS
Cronbachâs alphas for the scale were low. When an 8-item version of the scale was evaluated, alphas improved and item-total correlations remained strong or improved. Midlife women and breast cancer survivors did not have significantly different somatosensory amplification total or item scores after adjusting for group differences in demographics. Somatosensory amplification was significantly correlated with hot flash interference, perceived control over hot flashes, and mood and sleep disturbance in both groups but the patterns of correlations differed slightly between groups and depending on whether the 10-item or 8-item scale was used.
CONCLUSION
Somatosensory amplification may be a relevant concept to assess in relation to the menopausal symptom experience of midlife women with and without breast cancer as it may represent a potential intervention target to improve the menopausal symptom experience
In Search of a Common European Approach to a Healthy Indoor Environment
Increasingly, policymakers in Europe and around the world are realizing the importance of healthy indoor environments for public health. Certain member states of the European Union (EU) have already achieved successes in improving indoor environmental quality, such as controlling certain contaminants (e.g., environmental tobacco smoke) or developing nationwide policies that address indoor air generally. However, a common European approach to achieving healthy indoor environments is desirable for several reasons including providing a broader recognition of the problem of unhealthy indoor air, setting a policy example for all 27 EU member states, and achieving greater public health equity across the different European nations. In this article we address the question âWhy is it so difficult in the EU to develop a coherent approach on indoor environment?â We identify and describe four main barriers: a) the subsidiarity principle in EU policymaking, introducing decentralization of decision making to the member states; b) fragmentation of the topic of the indoor environment; c) the differences in climate and governance among different member states that make a common policy difficult; and d) economic issues. We discuss potential lessons and recommendations from EU and U.S. successes in achieving healthier indoor environments through various policy mechanisms
Secondary Sex Ratio among Women Exposed to Diethylstilbestrol in Utero
BACKGROUND. Diethylstilbestrol (DES), a synthetic estrogen widely prescribed to pregnant women during the mid-1900s, is a potent endocrine disruptor. Previous studies have suggested an association between endocrine-disrupting compounds and secondary sex ratio. METHODS. Data were provided by women participating in the National Cancer Institute (NCI) DES Combined Cohort Study. We used generalized estimating equations to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the relation of in utero DES exposure to sex ratio (proportion of male births). Models were adjusted for maternal age, child's birth year, parity, and cohort, and accounted for clustering among women with multiple pregnancies. RESULTS. The OR for having a male birth comparing DES-exposed to unexposed women was 1.05 (95% CI, 0.95-1.17). For exposed women with complete data on cumulative DES dose and timing (33%), those first exposed to DES earlier in gestation and to higher doses had the highest odds of having a male birth. The ORs were 0.91 (95% C, 0.65-1.27) for first exposure at â„ 13 weeks gestation to < 5 g DES; 0.95 (95% CI, 0.71-1.27) for first exposure at â„ 13 weeks to â„ 5 g; 1.16 (95% CI, 0.96-1.41) for first exposure at < 13 weeks to < 5 g; and 1.24 (95% CI, 1.04-1.48) for first exposure at < 13 weeks to â„ 5 g compared with no exposure. Results did not vary appreciably by maternal age, parity, cohort, or infertility history. CONCLUSIONS. Overall, no association was observed between in utero DES exposure and secondary sex ratio, but a significant increase in the proportion of male births was found among women first exposed to DES earlier in gestation and to a higher cumulative dose.National Cancer Institute (N01-CP-21168, N01-CP-51017, N01-CP-01289
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