Urban areas are considered net consumers of materials and energy, attracting these from the surrounding hinterland and other parts of the planet. The way these flows are transformed and returned to ...the environment by the city is important for addressing questions of sustainability and the effect of human behavior on the metabolism of the city. The present work explores these questions with the use of systems analysis, specifically in the form of a Multi-sectoral Systems Analysis (MSA), a tool for research and for supporting decision-making for policy and investment. The application of MSA is illustrated in the context of Greater London, with these three objectives: (a) estimating resource fluxes (nutrients, water and energy) entering, leaving and circulating within the city-watershed system; (b) revealing the synergies and antagonisms resulting from various combinations of water-sector innovations; and (c) estimating the economic benefits associated with implementing these technologies, from the point of view of production of fertilizer and energy, and the reduction of greenhouse gases. Results show that the selection of the best technological innovation depends on which resource is the focus for improvement. Urine separation can potentially recover 47% of the nitrogen in the food consumed in London, with revenue of $33 M per annum from fertilizer production. Collecting food waste in sewers together with growing algae in wastewater treatment plants could beneficially increase the amount of carbon release from renewable energy by 66%, with potential annual revenues of $58 M from fuel production.
•The Multi-sectoral Systems Analysis is described as a decision support tool.•Four technologies are assessed for their impact on London's urban metabolism.•The focus is on the flows of nitrogen, phosphorus, carbon, water, and energy.•Alternative technologies have a key role for the recovery of nutrients.•The largest economic benefits are associated with water use reduction.
Recently, a comparison between the locations of 6.7-GHz methanol masers and dust continuum emission has renewed speculation that these masers can be associated with evolved stars. The implication of ...such a scenario would be profound, especially for the interpretation of large surveys for 6.7-GHz masers, individual studies where high-mass star formation has been inferred from the presence of 6.7-GHz methanol masers and for the pumping mechanisms of these masers. We have investigated the two instances where 6.7-GHz methanol masers have been explicitly suggested to be associated with evolved stars, and we find the first to be associated with a standard high-mass star formation region, and the second to be a spurious detection. We also find no evidence to suggest that the methanol maser action can be supported in the environments of evolved stars. We thereby confirm their exclusive association with high-mass star formation regions.
Cities are major drivers of energy consumption and greenhouse gas emissions--the sources of anthropocentric climate change, whilst also concentrating people, buildings, and infrastructures and ...therefore potential risk and impacts of the latter. As a consequence, planning for climate change in urban areas does not only provide the opportunity but should necessitate considering interactions between mitigation and adaptation actions. However, existing research found that only a minority of urban areas consider both mitigation and adaptation in their climate action plans, i.e. 147 Climate Change Action Plans (CCAPs) were identified among a representative sample of 885 European cities. We investigate these 147 CCAPs to understand the degree of integration of adaptation and mitigation and draw implications for the maximization of synergies and co-benefits of such a combined approach. Using the developed scoring framework to evaluate the level of integration of CCAPs, the research finds that most of the plans reveal a ‘moderate’ level of integration. Moderate integration characterizes a plan that identifies sources of emissions and vulnerabilities to climate change, as well as some qualitative consideration of the synergies, but one that lacks a systematic consideration of potential integration opportunities. Furthermore, the analysis reveals that one of the main gaps of the evaluation and implementation of more integrated climate change actions in cities is the insufficient quantitative evaluation of the costs and funding schemes for adaptation and mitigation action implementation.
•Review and assessment of the level of integration of adaptation and mitigation in 147 EU urban climate change action plans.•Development and application of the Urban Climate Change Integration Index (UCCII).•Review and analysis of synergies and co-benefits of climate mitigation and adaptation actions.•Mitigation objectives are still more prominent than adaptation objectives in integrated urban climate change plans.•Discussion on capacity gaps and needs of local governments to understand, plan and implement integrated approaches.
Pollution reduction from waste management and energy generation is necessary to mitigate climate change and is one of the major challenges of the 21st century. This can be achieved through the ...development of innovative energy recovery technologies from biomass and wastes, such as microwave plasma gasification. An envelope of stable CO2 plasma operation is described, by varying working gas flow rate at applied microwave powers between 1 and 6 kW, whereas H2O plasma operation is possible with flow rate ranging from 20 to 50 g/min and microwave powers between 2.5 and 6 kW. The temperature generated in a large chamber connected to the plasma torch is recorded, reaching up to 850 °C, showing a heterogeneous temperature distribution. In addition, optical emission spectroscopy measurements provide an insight into plasma chemistry and demonstrate the dissociation of CO2 and H2O molecules at extremely high temperatures of up to 6300 °C assuming local thermodynamic equilibrium. The experimental results demonstrate that the microwave plasma torch provides an ideal environment for gasification with high temperature and very chemically reactive species. This study provides valuable information for the design of microwave plasma gasification reactors with great potential for effective solid feedstock conversion into high quality syngas for energy production.
•CO2 and H2O plasma operation in a wide range of operating conditions.•Temperatures up to 850 °C achieved in chamber connected to the plasma torch.•CO2 and H2O found to dissociate along 14 cm of the plasma plume.•Temperatures from 6300 °C to 2300 °C achieved along 14 cm of the plasma plume.
Aim Despite advances in surgical technique, parastomal herniation is common. This systematic review aims to assess the efficacy of prophylactic mesh at primary operation in reducing the incidence of ...parastomal hernia.
Method Medline, EMBASE and CENTRAL were searched for relevant publications between January 1980 and January 2010. The search strategy included text terms and MESH headings for parastomal hernia, mesh and prevention and/or prophylaxis of hernia. No language restrictions were applied. Bibliographies from the papers requested in full were manually checked. All randomized controlled trials were included regardless of the language of publication. Results were extracted from the papers by two observers independently on a predefined data sheet. Disagreements were resolved by discussion. REVMAN 5 was used for statistical analysis.
Results Of 27 possible studies three randomized controlled trials fulfilled the criteria for systematic review, with a total of 128 patients (mesh 64, no mesh 64). The two study groups were well matched demographically. The incidence of parastomal hernia in the mesh group was 12.5% (8/64) compared with 53% (34/64) in the control group (P < 0.0001). There was no difference in mesh related morbidity in the two groups.
Conclusion Although only three trials with 128 patients fulfilled the criteria for this systematic review, the data suggest that the use of prophylactic prosthetic mesh at the time of primary stoma formation reduces the incidence of parastomal hernia.
It is urgent to reduce CO2 emissions to mitigate the impacts of climate change. The development of advanced conversion technologies integrated with plasma torches provides a path for the optimisation ...of clean energy recovery from biomass and wastes, thus substituting fossil fuels utilization. This article presents the temperature characterisation within a laboratory-scale microwave-induced plasma reactor operated with air, H2O and CO2 as the plasma working gases. The benefits associated with the plasma torch are highlighted and include rapid responses of the plasma and the temperature profile within the reactor to changing operating conditions. The average temperature near the side wall in the laboratory-scale reactor is proportional to the applied microwave power, ranging from 550 °C at 2 kW to 850 °C at 5 kW, while significantly higher temperatures are locally present within the plasma plume. The described system demonstrates promising conditions that are ideal for effective energy recovery from biomass and wastes into clean fuel gas.
•Comparable temperatures in reactor for air, H2O and CO2 plasmas at specific power.•Quick reactor warm-up to 650 °C in less than 5 min.•More homogeneous temperatures at high flow rate and high applied microwave power.•Average temperature near side wall of reactor up to 850 °C at 5 kW microwave power.•Temperature up to 1000 °C recorded at the bottom of the plasma reactor.
Chest radiographs are used for diagnosis and severity assessment in tuberculosis (TB). The extent of disease as determined by smear grade and cavitation as a binary measure can predict 2-month smear ...results, but little has been done to determine whether radiological severity reflects the bacterial burden at diagnosis.
Pre-treatment chest x-rays from 1837 participants with smear-positive pulmonary TB enrolled into the REMoxTB trial (Gillespie et al., N Engl J Med 371:1577-87, 2014) were retrospectively reviewed. Two clinicians blinded to clinical details using the Ralph scoring system performed separate readings. An independent reader reviewed discrepant results for quality assessment and cavity presence. Cavitation presence was plotted against time to positivity (TTP) of sputum liquid cultures (MGIT 960). The Wilcoxon rank sum test was performed to calculate the difference in average TTP for these groups. The average lung field affected was compared to log
TTP by linear regression. Baseline markers of disease severity and patient characteristics were added in univariable regression analysis against radiological severity and a multivariable regression model was created to explore their relationship.
For 1354 participants, the median TTP was 117 h (4.88 days), being 26 h longer (95% CI 16-30, p < 0.001) in patients without cavitation compared to those with cavitation. The median percentage of lung-field affected was 18.1% (IQR 11.3-28.8%). For every 10-fold increase in TTP, the area of lung field affected decreased by 11.4%. Multivariable models showed that serum albumin decreased significantly as the percentage of lung field area increased in both those with and without cavitation. In addition, BMI and logged TTP had a small but significant effect in those with cavitation and the number of severe TB symptoms in the non-cavitation group also had a small effect, whilst other factors found to be significant on univariable analysis lost this effect in the model.
The radiological severity of disease on chest x-ray prior to treatment in smear positive pulmonary TB patients is weakly associated with the bacterial burden. When compared against other variables at diagnosis, this effect is lost in those without cavitation. Radiological severity does reflect the overall disease severity in smear positive pulmonary TB, but we suggest that clinicians should be cautious in over-interpreting the significance of radiological disease extent at diagnosis.
Reproductive success often declines with breeding date in diverse taxa, including temperate-nesting bird species. The date hypothesis predicts that seasonally deteriorating environmental quality ...drives this pattern. While mechanisms are not fully understood, a seasonal increase in parasitism may contribute to the declining quality of nestlings hatched later in the season. We examined the effect of ectoparasites on seasonal variation in indices of nestling quality and survival in Tree Swallows (Tachycineta bicolor (Vieillot, 1808)) at breeding sites in British Columbia (PG) and Saskatchewan (SDNRA). In a parasite removal experiment, we detected no seasonal trend in flea abundance and, contrary to expectation, there were fewer blow flies in nests of late breeders. Negative effects of parasites on nestlings were documented at PG, where lengths of primary feather and head–bill were affected. Parental, rather than environmental, quality had the greatest effect on reproductive success at PG, as nestling survival declined seasonally regardless of treatment and despite seasonally increasing food biomass. Nestlings in control (i.e., parasitized) nests at SDNRA had elevated feather corticosterone levels, but no other effects of parasites were detected possibly because parent birds were of higher quality or parents and offspring had greater access to food such that nestlings were capable of coping with parasite-related challenges.
Molecular tests hold great potential for tuberculosis (TB) diagnosis, but are costly, time consuming, and HIV-infected patients are often sputum scarce. Therefore, alternative approaches are needed. ...We evaluated automated digital chest radiography (ACR) as a rapid and cheap pre-screen test prior to Xpert MTB/RIF (Xpert). 388 suspected TB subjects underwent chest radiography, Xpert and sputum culture testing. Radiographs were analysed by computer software (CAD4TB) and specialist readers, and abnormality scores were allocated. A triage algorithm was simulated in which subjects with a score above a threshold underwent Xpert. We computed sensitivity, specificity, cost per screened subject (CSS), cost per notified TB case (CNTBC) and throughput for different diagnostic thresholds. 18.3% of subjects had culture positive TB. For Xpert alone, sensitivity was 78.9%, specificity 98.1%, CSS $13.09 and CNTBC $90.70. In a pre-screening setting where 40% of subjects would undergo Xpert, CSS decreased to $6.72 and CNTBC to $54.34, with eight TB cases missed and throughput increased from 45 to 113 patients/day. Specialists, on average, read 57% of radiographs as abnormal, reducing CSS ($8.95) and CNTBC ($64.84). ACR pre-screening could substantially reduce costs, and increase daily throughput with few TB cases missed. These data inform public health policy in resource-constrained settings.
Past, present, and future of UHECR observations Dawson, B R; Fukushima, M; Sokolsky, P
Progress of theoretical and experimental physics,
12/2017, Letnik:
2017, Številka:
12
Journal Article
Recenzirano
Odprti dostop
Abstract
Great advances have been made in the study of ultra-high energy cosmic rays (UHECR) in the past 2 decades. These include the discovery of the spectral cut-off near $5\times 10^{19}$ eV and ...complex structure at lower energies, as well as increasingly precise information about the composition of cosmic rays as a function of energy. Important improvements in techniques, including extensive surface detector arrays and high resolution air fluorescence detectors, have been instrumental in facilitating this progress. We discuss the status of the field, including the open questions about the nature of spectral structure, systematic issues related to our understanding of composition, and emerging evidence for anisotropy at the highest energies. We review prospects for upgraded and future observatories including Telescope Array, Pierre Auger, and JEM-EUSO, as well as other space-based proposals, and discuss promising new technologies based on radio emission from extensive air showers produced by UHECR.
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