Agricultural ditches are hotspots of greenhouse gas emissions controlled by nutrient input.

Agricultural ditches are pervasive in agricultural areas and are potential greenhouse gas (GHG) hotspots, since they directly receive abundant nutrients from neighboring farmlands. However, few studies measure GHG concentrations or fluxes in this particular water course, likely resulting in underestimations of GHG emissions from agricultural regions. Here we conducted a one-year field study to investigate the GHG concentrations and fluxes from typical agricultural ditch systems, which included four different types of ditches in an irrigation district located in the North China Plain. The results showed that almost all the ditches were large GHG sources. The mean fluxes were 333 µmol m-2 h-1 for CH4, 7.1 mmol m-2 h-1 for CO2, and 2.4 µmol m-2 h-1 for N2O, which were approximately 12, 5, and 2 times higher, respectively, than that in the river connecting to the ditch systems. Nutrient input was the primary driver stimulating GHG production and emissions, resulting in GHG concentrations and fluxes increasing from the river to ditches adjacent to farmlands, which potentially received more nutrients. Nevertheless, the ditches directly connected to farmlands showed lower GHG concentrations and fluxes compared to the ditches adjacent to farmlands, possibly due to seasonal dryness and occasional drainage. All the ditches covered approximately 3.3% of the 312 km2 farmland area in the study district, and the total GHG emission from the ditches in this area was estimated to be 26.6 Gg CO2-eq yr-1, with 17.5 Gg CO2, 0.27 Gg CH4, and 0.006 Gg N2O emitted annually. Overall, this study demonstrated that agricultural ditches were hotspots of GHG emissions, and future GHG estimations should incorporate this ubiquitous but underrepresented water course.

Restoration impacts on rates of denitrification and greenhouse gas fluxes from tropical coastal wetlands.

Forested coastal wetlands are globally important systems sequestering carbon and intercepting nitrogen pollution from nutrient-rich river systems. Coastal wetlands that have suffered extensive disturbance are the target of comprehensive restoration efforts. Accurate assessment of restoration success requires detailed mechanistic understanding of wetland soil biogeochemical functioning across restoration chrono-sequences, which remains poorly understood for these sparsely investigated systems. This study investigated denitrification and greenhouse gas fluxes in mangrove and Melaleuca forest soils of Vietnam, using the 15N-Gas flux method. Denitrification-derived N2O was significantly higher from Melaleuca than mangrove forest soils, despite higher potential rates of total denitrification in the mangrove forest soils (8.1 ng N g-1 h-1) than the Melaleuca soils (6.8 ng N g-1 h-1). Potential N2O and CO2 emissions were significantly higher from the Melaleuca soils than from the mangrove soils. Disturbance and subsequent recovery had no significant effect on N biogeochemistry except with respect to the denitrification product ratio in the mangrove sites, which was highest from the youngest mangrove site. Potential CO2 and CH4 fluxes were significantly affected by restoration in the mangrove soils. The lowest potential CO2 emissions were observed in the mid-age plantation and potential CH4 fluxes decreased in the older forests. The mangrove system, therefore, may remove excess N and improve water quality with low greenhouse gas emissions, whereas in Melaleucas, increased N2O and CO2 emissions also occur. These emissions are likely balanced by higher carbon stocks observed in the Melaleuca soils. These mechanistic insights highlight the importance of ecosystem restoration for pollution attenuation and reduction of greenhouse gas emissions from coastal wetlands. Restoration efforts should continue to focus on increasing wetland area and function, which will benefit local communities with improved water quality and potential for income generation under future carbon trading.

Polygenic basis and biomedical consequences of telomere length variation.

Telomeres, the end fragments of chromosomes, play key roles in cellular proliferation and senescence. Here we characterize the genetic architecture of naturally occurring variation in leukocyte telomere length (LTL) and identify causal links between LTL and biomedical phenotypes in 472,174 well-characterized UK Biobank participants. We identified 197 independent sentinel variants associated with LTL at 138 genomic loci (108 new). Genetically determined differences in LTL were associated with multiple biological traits, ranging from height to bone marrow function, as well as several diseases spanning neoplastic, vascular and inflammatory pathologies. Finally, we estimated that, at the age of 40 years, people with an LTL >1 s.d. shorter than the population mean had a 2.5-year-lower life expectancy compared with the group with ≥1 s.d. longer LDL. Overall, we furnish new insights into the genetic regulation of LTL, reveal wide-ranging influences of LTL on physiological traits, diseases and longevity, and provide a powerful resource available to the global research community.

Genome-wide Association Analysis in Humans Links Nucleotide Metabolism to Leukocyte Telomere Length.

Leukocyte telomere length (LTL) is a heritable biomarker of genomic aging. In this study, we perform a genome-wide meta-analysis of LTL by pooling densely genotyped and imputed association results across large-scale European-descent studies including up to 78,592 individuals. We identify 49 genomic regions at a false dicovery rate (FDR) < 0.05 threshold and prioritize genes at 31, with five highlighting nucleotide metabolism as an important regulator of LTL. We report six genome-wide significant loci in or near SENP7, MOB1B, CARMIL1, PRRC2A, TERF2, and RFWD3, and our results support recently identified PARP1, POT1, ATM, and MPHOSPH6 loci. Phenome-wide analyses in >350,000 UK Biobank participants suggest that genetically shorter telomere length increases the risk of hypothyroidism and decreases the risk of thyroid cancer, lymphoma, and a range of proliferative conditions. Our results replicate previously reported associations with increased risk of coronary artery disease and lower risk for multiple cancer types. Our findings substantially expand current knowledge on genes that regulate LTL and their impact on human health and disease.

Bidirectional association between disturbed sleep and neuropathic pain symptoms: a prospective cohort study in post-total joint replacement participants.

BACKGROUND: Disturbed sleep is strongly correlated with chronic pain. The aim of this study was to examine the association between sleep disturbance and incident joint pain focusing on neuropathic-like pain symptoms. METHODS: A total of 423 individuals who had undergone total joint replacement (TJR) for osteoarthritis were assessed at the mean time of 3.6 years post-surgery and again at 5.9 years post-TJR, using the Medical Outcomes Survey sleep subscale, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and painDETECT questionnaire instruments. Cox hazard ratios (HRs) and 95% confidence intervals (CIs) were computed adjusting for age, body mass index, sex, and use of hypnotic and analgesic medication. RESULTS: The presence of neuropathic pain symptoms predicted incidence of disturbed sleep after adjustment for covariates and pain severity (adjusted HR [aHR] 2.01, 95% CI: 1.00-4.10; p<0.05). There was no association between joint pain and incidence of disturbed sleep when individuals with neuropathic pain symptoms at the baseline visit were excluded (aHR 1.11, 95% CI: 0.47-2.67). Disturbed sleep at baseline predicted incident neuropathic joint pain symptoms (aHR 2.75, 95% CI: 1.21-6.26; p<0.016) but had no effect on incidence of joint pain when all types of pain were considered together (aHR 0.63, 95% CI: 0.30-1.39). CONCLUSION: These data suggest a causal bidirectional link between sleep disturbance and joint pain with neuropathic features but not with other types of joint pain.

Neuropathic pain-like symptoms and pre-surgery radiographic severity contribute to patient satisfaction 4.8 years post-total joint replacement.

AIM: To investigate a comprehensive range of factors that contribute to long-term patient satisfaction post-total joint replacement (TJR) in people who had undergone knee or hip replacement for osteoarthritis. METHODS: Participants (n = 1151) were recruited from Nottinghamshire post-total hip or knee replacement. Questionnaire assessment included medication use, the pain-DETECT questionnaire (PDQ) to assess neuropathic pain-like symptoms (NP) and TJR satisfaction measured on average 4.8 years post-TJR. Individual factors were tested for an association with post-TJR satisfaction, before incorporating all factors into a full model. Data reduction was carried out using LASSO and receiver operator characteristic (ROC) curve analysis was used to quantify the contribution of variables to post-TJR satisfaction. RESULTS: After data reduction, the best fitting model for post-TJR satisfaction included various measures of pain, history of revision surgery, smoking, pre-surgical X-ray severity, WOMAC function scores and various comorbidities. ROC analysis of this model gave AUC = 0.83 (95%CI: 0.80-0.85). PDQ scores were found to capture much of the variation in post-TJR satisfaction outcomes: AUC = 0.79 (0.75-0.82). Pre-surgical radiographic severity was associated with higher post-TJR satisfaction: ORsatisfied = 2.06 (95%CI: 1.15-3.69), P = 0.015. CONCLUSION: These results highlight the importance of pre-surgical radiographic severity, post-TJR function, analgesic medication use and NP in terms of post-TJR satisfaction. The PDQ appears to be a useful tool in capturing factors that contribute to post-TJR satisfaction.

Use of prescription analgesic medication and pain catastrophizing after total joint replacement surgery.

OBJECTIVE: To survey the use of analgesic medication 4.8 years after total joint replacement (TJR) surgery and assess the determinants of medication usage. PATIENTS AND METHODS: Of 852 patients who had undergone TJR for osteoarthritis were recruited from secondary care. Participants (mean age, 73.7 years) responded to a questionnaire on medication use, physical function and pain (WOMAC, VAS and body pain), pain catastrophizing and illness behaviour (somatization). RESULTS: Only 37% of study participants were not on any pain relief medication, 25.1% were taking opioids, 6.9% were taking prescription NSAIDs and 25.9% were taking only non-prescription analgesics. Use of NSAIDs correlated with presence of back pain, body pain and high illness behaviour. The strongest associations with use of opioids were severe joint pain, high pain catastrophizing, body and back pain. After adjustment for covariates plus presence of pain, catastrophizing remained significantly associated with higher risk of opioid use (OR = 1.66, 95% CI: 1.13-2.43, p < 0.009) and of other prescription medication that can be used to treat pain (anti-depressants, anti-epileptics and hypnotics) (OR = 2.52, 95% CI: 1.61-3.95, p < 0.0005). CONCLUSIONS: Use of opioid medication 4 years post-TJR is very high in our study population. In addition to joint, back and body pain, a major contributor to opioid use is pain catastrophizing. Our data suggest that current opioid and other analgesic prescribing patterns may benefit from considering the catastrophizing characteristics of patients.