Changes in net ecosystem exchange over Europe during the 2018 drought based on atmospheric observations.

The 2018 drought was one of the worst European droughts of the twenty-first century in terms of its severity, extent and duration. The effects of the drought could be seen in a reduction in harvest yields in parts of Europe, as well as an unprecedented browning of vegetation in summer. Here, we quantify the effect of the drought on net ecosystem exchange (NEE) using five independent regional atmospheric inversion frameworks. Using a network of atmospheric CO2 mole fraction observations, we estimate NEE with at least monthly and 0.5° × 0.5° resolution for 2009-2018. We find that the annual NEE in 2018 was likely more positive (less CO2 uptake) in the temperate region of Europe by 0.09 ± 0.06 Pg C yr-1 (mean ± s.d.) compared to the mean of the last 10 years of -0.08 ± 0.17 Pg C yr-1, making the region close to carbon neutral in 2018. Similarly, we find a positive annual NEE anomaly for the northern region of Europe of 0.02 ± 0.02 Pg C yr-1 compared the 10-year mean of -0.04 ± 0.05 Pg C yr-1. In both regions, this was largely owing to a reduction in the summer CO2 uptake. The positive NEE anomalies coincided spatially and temporally with negative anomalies in soil water. These anomalies were exceptional for the 10-year period of our study. This article is part of the theme issue 'Impacts of the 2018 severe drought and heatwave in Europe: from site to continental scale'.

Five decades of northern land carbon uptake revealed by the interhemispheric CO2 gradient.

The global land and ocean carbon sinks have increased proportionally with increasing carbon dioxide emissions during the past decades1. It is thought that Northern Hemisphere lands make a dominant contribution to the global land carbon sink2-7; however, the long-term trend of the northern land sink remains uncertain. Here, using measurements of the interhemispheric gradient of atmospheric carbon dioxide from 1958 to 2016, we show that the northern land sink remained stable between the 1960s and the late 1980s, then increased by 0.5 ± 0.4 petagrams of carbon per year during the 1990s and by 0.6 ± 0.5 petagrams of carbon per year during the 2000s. The increase of the northern land sink in the 1990s accounts for 65% of the increase in the global land carbon flux during that period. The subsequent increase in the 2000s is larger than the increase in the global land carbon flux, suggesting a coincident decrease of carbon uptake in the Southern Hemisphere. Comparison of our findings with the simulations of an ensemble of terrestrial carbon models5,8 over the same period suggests that the decadal change in the northern land sink between the 1960s and the 1990s can be explained by a combination of increasing concentrations of atmospheric carbon dioxide, climate variability and changes in land cover. However, the increase during the 2000s is underestimated by all models, which suggests the need for improved consideration of changes in drivers such as nitrogen deposition, diffuse light and land-use change. Overall, our findings underscore the importance of Northern Hemispheric land as a carbon sink.

Biopsy-based comparison of liquid-based, thin-layer preparations to conventional Pap smears.

OBJECTIVE: To evaluate and compare histologic diagnosis of squamous intraepithelial neoplasia and cancer of the cervix with cytologic diagnosis using the conventional Pap smear versus the AutoCyte PREP liquid-based, thin-layer preparation. STUDY DESIGN: Two randomly selected, large patient groups from the same population were studied using two different cervical cytology preparation techniques. Cytologic results were compared to histologic diagnosis to estimate the relative sensitivities and specificities of the preparations. RESULTS: AutoCyte's liquid-based, thin-layer preparation method demonstrated improved agreement with histologic diagnosis as compared to the conventional Pap smear. This result supported the previously reported finding that use of this thin-layer method reduced atypical squamous cells of undetermined significance cases and substantially increased the detection of squamous intraepithelial lesions (SILs). CONCLUSION: Our cytohistologic correlation for conventional Pap smears and the AutoCyte PREP liquid-based preparations demonstrate that the increased rate of both low and high grade SILs on AutoCyte PREP reflects real detection as opposed to overdiagnosis.

Human papillomavirus (HPV) DNA assay as an adjunct to liquid-based Pap test in the diagnostic triage of women with an abnormal Pap smear.

OBJECTIVE: The diagnostic performance and clinical value of the combined use of liquid-based Pap test and human papillomavirus testing were determined in 336 patients with a previous abnormal smear. METHOD: Subsequent histologic evaluation was used as definitive diagnosis. RESULT: The combined use of liquid-based Pap test and HPV DNA testing showed higher rates in sensitivity (99.0%), specificity (59.3%), positive predictive value (89.9%) and negative predictive value (94.5%) than either cytology alone (sensitivity 98.8%, specificity 45.7%, positive predictive value 84.7%, negative predictive value 92.6%) or HPV DNA testing alone (sensitivity 84.9%, specificity 67.4%, positive predictive value 88.8%, negative predictive value 59.5%). CONCLUSION: The study demonstrated that the diagnostic accuracy for cervical cancer and its precursors was improved by using the liquid-based Pap test as a primary diagnostic procedure and HPV assay as an adjunctive test. This information may assist the clinicians in triaging patients with equivocal cytologic cervical atypias.