53 research outputs found

    Microbial carbon and nitrogen cycling responses to drought and temperature in differently managed mountain grasslands

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    Grassland management can modify soil microbial carbon (C)and nitrogen (N)cycling, affecting the resistance to extreme weather events, which are predicted to increase in frequency and magnitude in the near future. However, effects of grassland management on microbial C and N cycling and their responses to extreme weather events, such as droughts and heatwaves, have rarely been tested in a combined approach. We therefore investigated whether grassland management affects microbial C and N cycling responses to drought and temperature manipulation. We collected soils from in situ drought experiments conducted in an extensively managed and an abandoned mountain grassland and incubated them at two temperature levels. We measured microbial respiration and substrate incorporation, as well as gross rates of organic and inorganic N cycling to estimate microbial C and N use efficiencies (CUE and NUE). The managed grassland was characterized by lower microbial biomass, lower fungi to bacteria ratio, and higher microbial CUE, but only slightly different microbial NUE. At both sites drought induced a shift in microbial community composition driven by an increase in Gram-positive bacterial abundance. Drought significantly reduced C substrate respiration and incorporation by microbes at both sites, while microbial CUE remained constant. In contrast, drought increased gross rates of N mineralization at both sites, whereas gross amino acid uptake rates only marginally changed. We observed a significant direct, as well as interactive effect between land management and drought on microbial NUE. Increased temperatures significantly stimulated microbial respiration and reduced microbial CUE independent of drought or land management. Although microbial N processing rates showed no clear response, microbial NUE significantly decreased at higher temperatures. In summary in our study, microbial CUE, in particular respiration, is more responsive to temperature changes. Although N processing rates were stronger responding to drought than to temperature microbial NUE was affected by both drought and temperature increase. We conclude that direct effects of drought and heatwaves can induce different responses in soil microbial C and N cycling similarly in the studied land management systems

    Internet-based search of randomised trials relevant to mental health originating in the Arab world

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    BACKGROUND: The internet is becoming a widely used source of accessing medical research through various on-line databases. This instant access to information is of benefit to busy clinicians and service users around the world. The population of the Arab World is comparable to that of the United States, yet it is widely believed to have a greatly contrasting output of randomised controlled trials related to mental health. This study was designed to investigate the existence of such research in the Arab World and also to investigate the availability of this research on-line. METHODS: Survey of findings from three internet-based potential sources of randomised trials originating from the Arab world and relevant to mental health care. RESULTS: A manual search of an Arabic online current contents service identified 3 studies, MEDLINE, EMBASE, and PsycINFO searches identified only 1 study, and a manual search of a specifically indexed, study-based mental health database, PsiTri, revealed 27 trials. CONCLUSION: There genuinely seem to be few trials from the Arab world and accessing these on-line was problematic. Replication of some studies that guide psychiatric/psychological practice in the Arab world would seem prudent

    Large-scale unit commitment under uncertainty: an updated literature survey

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    The Unit Commitment problem in energy management aims at finding the optimal production schedule of a set of generation units, while meeting various system-wide constraints. It has always been a large-scale, non-convex, difficult problem, especially in view of the fact that, due to operational requirements, it has to be solved in an unreasonably small time for its size. Recently, growing renewable energy shares have strongly increased the level of uncertainty in the system, making the (ideal) Unit Commitment model a large-scale, non-convex and uncertain (stochastic, robust, chance-constrained) program. We provide a survey of the literature on methods for the Uncertain Unit Commitment problem, in all its variants. We start with a review of the main contributions on solution methods for the deterministic versions of the problem, focussing on those based on mathematical programming techniques that are more relevant for the uncertain versions of the problem. We then present and categorize the approaches to the latter, while providing entry points to the relevant literature on optimization under uncertainty. This is an updated version of the paper "Large-scale Unit Commitment under uncertainty: a literature survey" that appeared in 4OR 13(2), 115--171 (2015); this version has over 170 more citations, most of which appeared in the last three years, proving how fast the literature on uncertain Unit Commitment evolves, and therefore the interest in this subject

    A hospital led promotion campaign aimed to increase bicycle helmet wearing among children aged 11–15 living in West Berkshire 1992–98

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    Objectives—To evaluate the effect of a bicycle helmet promotion campaign on helmet wearing among cyclists less than 16 years of age from 1992–98. Setting—Reading, West Berkshire, UK. Methods—A hospital led bicycle helmet promotion campaign targeted at 5–15 year olds. The campaign focused on education with active involvement of the children, parents, schools, and safety organisations. Local media and children's celebrities raised the profile of the campaign and a low cost helmet purchase scheme was also set up. A self administered questionnaire survey of 3000, 11–15 year olds was carried out over the period of the campaign. A control group of 3000 teenagers was obtained from a neighbouring area without a helmet campaign. Accident and emergency (A&E) figures were obtained from the local hospital within the campaign area on all children aged under 16 years, attending with bicycle injuries. Unfortunately, no figures were available from the A&E department in the control area. Results—Self reported helmet use among 11–15 years olds living in the campaign area increased from 11% at the start of the campaign to 31% after five years (p<0.001), with no change in the control group. Hospital casualty figures in the campaign area for cycle related head injuries in the under 16 years age group, fell from 112.5/100 000 to 60.8/100 000 (from 21.6% of all cycle injuries to 11.7%; p<0.005). Conclusions—This hospital led community bicycle helmet promotion campaign directed at young people showed an increase in the number of children reporting that they "always" wore their helmet while cycling. There was a significantly higher rate of helmet wearing than in the control area, and a significant reduction in head injuries

    National oral health survey on refugees in Germany 2016/2017: caries and subsequent complications

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    Objectives!#!To assess oral health, caries prevalence, and subsequent complications among recently arrived refugees in Germany and to compare these findings with the German resident population.!##!Methods!#!This multicenter cross-sectional study recruited 544 refugees aged 3-75+ years; they were examined at ten registration institutions in four federal states in Germany by two calibrated dentists. The refugees were screened for caries (dmft/DMFT) and its complications (pufa/PUFA); this data was compared to the resident population via the representative national oral health surveys).!##!Results!#!The deciduous dentition of the 3-year-old refugees had a mean dmft value of 2.62 ± 3.6 compared with 0.48 dmft in the German resident population, and caries increased to 5.22 ± 3.4 for 6-7-year-olds (Germany: 1.73 dmft). Few refugee children had naturally healthy teeth (7% in 6-7-year-olds, Germany: 56%). In the permanent dentition, the gap in caries prevalence between refugees and the German population decreased with age (35-44-year-olds: 10.55 ± 7.1 DMFT; Germany: 11.2), but refugees exhibited more caries defects (35-44-year-olds DT = 3.13 ± 3.0; Germany: 0.5). German residents had more restorations (35-44-year-olds FT = 4.21 ± 4.6). Regarding complications, the 6-7-year-olds exhibited the highest pufa index (0.86 ± 1.4) which decreased in adolescence (13-17-year-olds, 0.18 ± 0.6) and increased in adults (45-64-year-olds, 0.45 ± 0.8).!##!Conclusion!#!The refugees had high caries experience, often untreated caries teeth and more complications compared with the German resident population, especially in children. Closing this gap by extending preventive systems to the refugees would decrease future treatment needs.!##!Clinical relevance!#!European countries should be prepared for the higher dental treatment needs in recent refugees, especially in children
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