Reversal of acidification in upland waters of the English Lake District

Water chemistry data are reported for five high-altitude standing waters in the English Lake District, with current average pH values in the range 5–7. The waters show long-term increases in pH, ranging from 0.3 to 0.8 pH units, between 1974 and 1997. The pH of Devoke Water, which was acidified only mildly, has returned to values estimated for the pre-industrial period (1850 and earlier). Alkalinity in Devoke Water increased from ca 20 μeq litre−1 in the early 1980s to ca 70 μeq litre−1 in the 1990s, and alkalinities in three of the other waters have increased by ca 20 μeq litre−1 since the 1970s. For the two intensively monitored sites (Devoke Water and Levers Water), significant decreases in the concentration of non-marine sulphate are demonstrated, which have taken place concurrently with decreases in the atmospheric deposition of pollutant sulphur. Approximate calculations suggest that the catchment of Levers Water was a sink for sulphur in the 1970s, and that the catchment of Devoke Water may currently be a source of sulphate. For neither Devoke Water nor Levers Water is there evidence of a long-term decrease in the concentration of non-marine base cations

Language Design Issues in Supporting Process-Oriented Computation in Persistent Environments

The problems of shared access to large bodies of information raise difficulties in the understanding and semantics of concurrency, distribution and stability. When the information is held in a persistent object store, these difficulties of understanding are extended to the interaction of the concepts of persistence and store with those above. Some of the difficulty is in deciding at what level the architecture or language operates, be it hardware or software. Other difficulties arise in the complexity of the problems of concurrency. In this paper we identify these difficulties and clarify them with regard to database programming language design. We propose a model of concurrency that may be used as a solution to the problems. It is based on the rendezvous of Ada and integrated with a polymorphic type system with inheritance. This yields a processoriented approach to system construction that has much in common with the objectoriented approach. We will demonstrate the facilities of the ..

Is planting trees the solution to reducing flood risks?

Flood risk and associated impacts are major societal and policy concerns following widespread flooding in December 2015, which cost the UK economy an estimated £5 billion. Increasing advocacy for alternatives to conventional hard engineering solutions is accompanied by demands for evidence. This study provides a systematic review and meta-analysis of direct evidence for the effect of tree cover on channel discharge. The results highlighted a deficiency in direct evidence. From 7 eligible studies of 156 papers reviewed, the results show that increasing tree cover has a small statistically significant effect on reducing channel discharge. Meta-analysis reveals that tree cover reduces channel discharge (standardised mean difference −0.35, 95%CI, −0.71 to 0.00), but the effect was variable (I2 = 81.91%), the potential for confounding was high, and publication bias is strongly suspected (Egger Test z = 3.0568, p =.002). Due to the lack of direct evidence the overall strength of evidence is low, indicating high uncertainty. Further primary research is required to understand reasons for heterogeneity and reduce uncertainty. A Bayesian network parameterised with data from the meta-analysis supports investment in integrated catchment management, particularly on infrastructure density and water storage (reservoirs), for effective responses to flood risk

Sustainability, the Next Generation Science Standards, and the Education of Future Teachers

The Next Generation Science Standards (NGSS) emphasize how human activities affect the Earth and how Earth processes impact humans, placing the concept of sustainability within the Earth and Space Sciences. We ask: how prepared are future teachers to address sustainability and systems thinking as encoded in the NGSS? And how can geoscientists support them? Most future teachers receive their Earth Science preparation in a single introductory geoscience course, but the content and delivery methods of these courses are not well matched to the NGSS knowledge and skills they will teach. We implemented a nationwide survey in undergraduate courses that addressed sustainability to some extent in order to assess career interests, behaviors, and motivations. Matched pre- and postdata (n = 1,125) respondents were divided into three groups: those very likely (22%), those somewhat likely (22%), and those not likely (56%) to become teachers. The very likely group resembles the current STEM teacher workforce in gender but is more diverse than the current workforce and the population currently enrolled in teacher preparation programs. The very likely group has higher rates of sustainable behaviors, is motivated by family and friends more than other groups, and is more likely to envision using their knowledge about sustainability in their careers. However, their understanding of key concepts, such as systems thinking, is limited. We suggest that curricular materials that address sustainability through concepts in introductory geoscience courses, such as those presented here, provide a means of reaching this group and better preparing future teachers to teach the NGSS

Colorectal Endoscopic Stenting Trial (CReST) for obstructing left-sided colorectal cancer: randomized clinical trial

Background Colorectal cancer often presents with obstruction needing urgent, potentially life-saving decompression. The comparative efficacy and safety of endoluminal stenting versus emergency surgery as initial treatment for such patients is uncertain. Methods Patients with left-sided colonic obstruction and radiological features of carcinoma were randomized to endoluminal stenting using a combined endoscopic/fluoroscopic technique followed by elective surgery 1–4 weeks later, or surgical decompression with or without tumour resection. Treatment allocation was via a central randomization service using a minimization procedure stratified by curative intent, primary tumour site, and severity score (Acute Physiology And Chronic Health Evaluation). Co-primary outcome measures were duration of hospital stay and 30-day mortality. Secondary outcomes were stoma formation, stenting completion and complication rates, perioperative morbidity, 6-month survival, 3-year recurrence, resource use, adherence to chemotherapy, and quality of life. Analyses were undertaken by intention to treat. Results Between 23 April 2009 and 22 December 2014, 245 patients from 39 hospitals were randomized. Stenting was attempted in 119 of 123 allocated patients (96.7 per cent), achieving relief of obstruction in 98 of 119 (82.4 per cent). For the 89 per cent treated with curative intent, there were no significant differences in 30-day postoperative mortality (3.6 per cent (4 of 110) versus 5.6 per cent (6 of 107); P = 0.48), or duration of hospital stay (median 19 (i.q.r. 11–34) versus 18 (10–28) days; P = 0.94) between stenting followed by delayed elective surgery and emergency surgery. Among patients undergoing potentially curative treatment, stoma formation occurred less frequently in those allocated to stenting than those allocated to immediate surgery (47 of 99 (47.5 per cent) versus 72 of 106 (67.9 per cent); P = 0.003). There were no significant differences in perioperative morbidity, critical care use, quality of life, 3-year recurrence or mortality between treatment groups. Conclusion Stenting as a bridge to surgery reduces stoma formation without detrimental effects. Registration number: ISRCTN13846816 (http://www.controlled-trials.com)