Cover Crop Effects on Nitrous Oxide Emissions: Role of Mineralizable Carbon

Nitrous oxide (N2O) emission from denitrification in agricultural soils often increases with N fertilizer and soil nitrate (NO3) concentrations. Overwintering cover crops in cereal rotations can decrease soil NO3 concentrations and may decrease N2O emissions. However, mineralizable C availability can be a more important control on N2O emission than NO3 concentration in fertilized soils, and cover crop residue provides mineralizable C input. We measured the effect of a winter rye (Secale cereale L.) cover crop on soil N2O emissions from a maize (Zea mays L.) cropping system treated with banded N fertilizer at three rates (0, 135, and 225 kg N ha–1) in Iowa. In addition, we conducted laboratory incubations to determine if potential N2O emissions were limited by mineralizable C or NO3 at these N rates. The rye cover crop decreased soil NO3 concentrations at all N rates. Although the cover crop decreased N2O emissions when no N fertilizer was applied, it increased N2O emissions at an N rate near the economic optimum. In laboratory incubations, N2O emissions from soils from fertilizer bands did not increase with added NO3, but did increase with added glucose. These results show that mineralizable C availability can control N2O emissions, indicating that C from cover crop residue increased N2O emissions from fertilizer band soils in the field. Mineralizable C availability should be considered in future evaluations of cover crop effects on N2O emissions, especially as cover crops are evaluated as a strategy to mitigate agricultural greenhouse gas emissions

Women's experiences of participating in a randomised trial comparing alternative policies for timing of cord clamping at very preterm birth: a questionnaire study

BACKGROUND: The Cord Pilot Trial compared two alternative policies for cord-clamping at very preterm birth at eight UK tertiary maternity units: clamping after at least 2 min and immediate neonatal care with cord intact, or clamping within 20 s and neonatal care after clamping. This paper reports views and experiences of the women who participated in the trial (261 randomised), based on data from two self-completed questionnaires. METHODS: Women were given or posted the first questionnaire between 4 and 8 weeks after birth, and posted a second similar questionnaire at 1 year. Both questionnaires included three questions about experiences of participating in the trial: (1) If time suddenly went backwards and you had to do it all over again, would you agree to participate in the Cord Pilot Trial?; (2) Please tell us if there was anything about the Cord Pilot Trial that you think could have been done better; and (3) Please tell us if there was anything about the Cord Pilot Trial, or your experiences of joining the trial, that you think were particularly good. RESULTS: One hundred and eighty-six women completed the first questionnaire and 133 completed the second. At both time points, 90% responded 'probably' or 'definitely' to participating in the trial again. More women randomised to deferred clamping responded 'definitely yes' than those allocated immediate clamping (78% versus 67% first questionnaire). Women were positive about the level of information and explanations, the friendly and caring staff, and the benefits for their baby and others as a result of participating in the trial. Suggestions for how the trial could be done better included being approached earlier, better staff communication about the trial, more information overall, and better timing of follow-up. CONCLUSIONS: Women were largely positive about participating in the trial. Nevertheless, they had suggestions for how the study could have been improved. These suggestions have implications for the design of future trials. TRIAL REGISTRATION: ISRCTN21456601 . Registered on 28 February 2013

Cord pilot trial, comparing alternative policies for timing of cord clamping before 32 weeks gestation: follow-up for women up to one year.

BACKGROUND: The Cord Pilot Trial compared two alternative policies for cord clamping at very preterm birth at eight UK maternity units: clamping after at least 2 min and immediate neonatal care (if needed) with cord intact, or clamping within 20 s and neonatal care after clamping. This paper reports follow-up of the women by two self-completed questionnaires up to one year after the birth. METHODS: Women were given or posted the first questionnaire between four and eight weeks after birth, usually before their baby was discharged, and were posted a second similar questionnaire at one year. The questionnaire included the Hospital Anxiety and Depression Scale; the Preterm Birth Experience and Satisfaction Scale (P-BESS) and questions about their baby's feeding. RESULTS: Of 261 women randomised (132 clamping ≥2 min, 129 clamping ≤20 s), six were excluded as birth was after 35+ 6 weeks (2, 4 in each group respectively). Six were not sent either questionnaire. The first questionnaire was given/sent to 244 and returned by 186 (76%) (79, 74%). The second, at one year, was sent to 242 and returned by 133 (55%) (66, 43%). On the first questionnaire, 89 (49%) had a score suggestive of an anxiety disorder, and 55 (30%) had a score suggestive of depression. Satisfaction with care at birth was high: median total P-BESS score 77 [interquartile range 68 to 84] (scale 17 to 85). There was no clear difference in anxiety, depression, or satisfaction with care between the two allocated groups. The median number of weeks after birth women breastfed/expressed was 16 (95% confidence interval (CI) 13 to 20, n = 119) for those allocated clamping ≥2 min and 12 (95% CI 11 to 16, n = 103) for those allocated clamping ≤20 s. CONCLUSIONS: The response rate was higher for the earlier questionnaire than at one year. A high proportion of women reported symptoms of anxiety or depression, however there were no clear differences between the allocated groups. Most women reported that they had breastfed or expressed milk and those allocated deferred cord clamping reported continuing this for slightly longer. TRIAL REGISTRATION: ISRCTN 21456601, registered 28th February 2013, http://www.isrctn.com/ISRCTN21456601

Extreme weather‐year sequences have nonadditive effects on environmental nitrogen losses

The frequency and intensity of extreme weather years, characterized by abnormal precipitation and temperature, are increasing. In isolation, these years have disproportionately large effects on environmental N losses. However, multi-year sequences of extreme weather years (e.g., wet-dry vs. dry-wet) and annual crop rotation (legume-cereal vs. cereal-legume) may interact to affect cumulative N losses across the complete crop rotation sequence. We calibrated and validated the DAYCENT model with a comprehensive set of biogeophysical measurements from a maizesoybean rotation managed at three different N fertilizer inputs with and without a winter cereal rye cover crop in Iowa, USA. Our objectives were to determine: i) how two-year sequences of extreme weather years interact with annual crop rotation sequence to affect two-year cumulative N losses, and ii) if the inclusion of a winter cover crop between corn and soybean and N fertilizer management mitigate the effect of extreme weather on N losses. Using historical weather data (1951-2013), we created nine two-year weather scenarios with all possible combinations of the hottest and driest (‘dry’), coolest and wettest (‘wet’), and average (‘normal’) weather years. We analyzed the effects of these scenarios following a period of relatively normal weather. Compared to the normal-normal two-year weather scenario, two-year extreme weather scenarios affected two-year cumulative NO3- leaching (range: -28 to +295%) more than N2O emissions (range: -54 to +21%). Moreover, the two-year weather scenarios had non-additive effects on N losses: although dry weather decreased NO3- leaching in isolation, two-year cumulative NO3- losses from the dry-wet scenario were 89% greater than the normal-normal scenario. Cover crops reduced the effect of extreme weather on NO3- leaching, but not N2O emissions. As the frequency of extreme weather events is expected to increase, understanding of interactions between crop rotation and interannual weather patterns can be used to mitigate the effect of extreme weather on environmental N losses

Life on a slippery slope: perceptions of health in adults with cystic fibrosis

This paper focuses on how adults with cystic fibrosis (CF) attending a specialist CF centre in the UK perceive their health. In common with many other genetic diseases, CF is traditionally conceptualised as a fatal childhood disease, yet the average survival age for those with CF has been steadily rising over the past half century. Thus it is now predicted that those born in 1990 will live on average for 40 years. To date, however, most sociological work has focused on children or adolescents affected by CF rather than on adults between the ages of 18 and 40, the focus of the study reported here. The paper shows that these adults' varying perceptions of health are related to the effects of CF, its treatment, and the context in which adults are placed. Four concepts of health are identified (health as 'normal', controllable, distressing and a release) along with certain styles, ways of coping and related strategies. Through these analytic distinctions the paper aims to make a contribution to the sociological understanding of lay concepts of health in adults with childhood or genetic disease

Analysis of RAD51C germline mutations in high-risk breast and ovarian cancer families and ovarian cancer patients

There is strong evidence that overtly inactivating mutations in RAD51C predispose to hereditary breast and ovarian cancer but the prevalence of such mutations, and whether they are associated with a particular clinical phenotype, remains unclear. Resolving these questions has important implications for the implementation of RAD51C into routine clinical genetic testing. Consequently, we have performed a large RAD51C mutation screen of hereditary breast and ovarian cancer families, and the first study of unselected patients diagnosed with ovarian cancer. Our data confirm a consistent but low frequency (2/335 families) of inactivating RAD51C mutations among families with a history of both breast and ovarian cancer and an absence of mutations among breast cancer only families (0/1,053 families). Our data also provide support for the designation of the missense variant p.Gly264Ser as a moderate penetrance allele