1,930 research outputs found
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Are calcareous soil ecosystems and associated drainage waters less susceptible to damage from winter road salting than acidic soil ecosystems?
Previous studies of upland roadside soils in Cumbria, that would normally be naturally acidic, have highlighted that (a) runoff from roads subjected to long-term road salting can dramatically raise soil pH down slope in upland areas; (b) the soil pH increase dramatically changes N cycling in soils down slope, increasing mineralisation of organic matter, ammonification, ammonium leaching down slope and nitrification and nitrate leaching; (c) the increase in nitrification substantially increases nitrate leaching to down-slope rivers, and this is readily detectable in field studies; and (d) loss of soil organic matter over decades of salting is so great that organic matter is no longer substantially solubilised by high salt concentrations found in soil solution below road drains. This paper tests and supports the hypothesis that such effects are minimal for more calcareous soil ecosystems. It examines the soil and soil solution chemistry on another Cumbrian upland highway, the A686 near Leadgate, Alston. Sodium % of soil CEC values for soil transects affected by spray containing road salt are similar at both the A6 and A686 sites. However, spatial trends in calcium, magnesium, ammonium, and nitrate concentrations as well as pH differ, as a direct result of the higher weathering rate of parent material and possibly also the presence of limestone walls above both spray-affected and control transects at the A686 site
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Effect of long-term changes in soil chemistry induced by road salt applications on N-transformations in roadside soils
Of several impacts of road salting on roadside soils, the potential disruption of the nitrogen cycle has been largely ignored. Therefore the fates of low-level ammonium-N and nitrate-N inputs to roadside soils impacted by salting over an extended period (decades) in the field have been studied. The use of road salts disrupts the proportional contributions of nitrate-N and ammonium-N to the mineral inorganic fraction of roadside soils. It is highly probable that the degree of salt exposure of the soil, in the longer term, controls the rates of key microbial N transformation processes. primarily by increasing soil pH. Additional influxes of ammonium-N to salt-impacted soils are rapidly nitrified therefore and, thereafter. increased leaching of nitrate-N to the local waterways occurs, which has particular relevance to the Water Framework Directive. The results reported are important when assessing the fate of inputs of ammonia to soils from atmospheric pollution. (c) 2007 Elsevier Ltd. All fights reserved
Speculation beyond technology: building scenarios through storytelling
‘Modern methods of construction’ is a term largely synonymous with the prefabrication of product components in factories. Emerging technologies, e.g. robotics and artificial intelligence (AI), are redefining the concept of modern methods of construction and destabilising the structure of the sector to meet the conditions of their implementation. Robotics and machine-based automation, for example, are expected to transform construction manufacturing techniques in rapid and significant ways, but the extent of change and the associated impacts on organisations, supply chains and business models that constitute the sector remains unknown. Existing foresight is dominated by trajectorial perspectives that overemphasise technological predictions and underemphasise the contextual stories of implementation most helpful in understanding technology adoption. An alternative approach presented here focuses on storytelling, the design of the scenarios and the visual images used to help convey these scenarios. These allow practitioners to explore how robotics and machine-based automation may play out in different characterisations of the industry. The research involved the analysis of an existing dataset to create four scenarios, before adapting and extending these scenarios through participatory workshops and interviews. Project participants were comprised of seven small and medium-sized enterprises (SMEs) in manufacturing and architectural fabrication, one tier 1 contractor, and two acclaimed industry experts from an industry advisory board and education centre
The occurrence of faults in the Bunter Sandstone Formation of the UK Sector of the Southern North Sea and the potential impact on storage capacity
The Triassic Bunter Sandstone Formation of the Southern North Sea is believed to have significant potential to store CO2 for climate change mitigation [1]. It has fair to good reservoir properties and a seal is provided by the mudstones of the Triassic Haisborough Group. It has been folded into domes and periclines (henceforth Bunter domes) by the post depositional late Triassic to Tertiary movement of the underlying evaporites of the Zechstein Group. These domes have been identified as targets for CO2 storage as they are very large and at least some of them have the ability to retain buoyant fluids, demonstrated by the presence of gas fields in some domes [2], [3], [4], [5] (though the majority of the formation is saline water-bearing). However, faults have been identified within the Haisborough Group cap rock directly above a number of the Bunter domes. The faults are thought to have formed as result of extensional stresses exerted during dome formation. They may have an impact on storage site security, as they could act as migration pathways for CO2 out of the storage site and therefore limit the number of Bunter domes that could be utilised for storage of CO2. This study considers the occurrence of faults in the cap rock above the Bunter domes and the potential impact on static capacity estimates
Hawking radiation in different coordinate settings: Complex paths approach
We apply the technique of complex paths to obtain Hawking radiation in
different coordinate representations of the Schwarzschild space-time. The
coordinate representations we consider do not possess a singularity at the
horizon unlike the standard Schwarzschild coordinate. However, the event
horizon manifests itself as a singularity in the expression for the
semiclassical action. This singularity is regularized by using the method of
complex paths and we find that Hawking radiation is recovered in these
coordinates indicating the covariance of Hawking radiation as far as these
coordinates are concerned.Comment: 18 pages, 2 figures, Uses IOP style file; final version; accepted in
Class. Quant. Gra
Cell and gene therapies at the forefront of innovative medical care: Implications for South Africa
The fields of cell and gene therapy are moving rapidly towards providing innovative cures for incurable diseases. A current and highly topical example is immunotherapies involving T-cells that express chimeric antigen receptors (CAR T-cells), which have shown promise in the treatment of leukaemia and lymphoma. These new medicines are indicative of the changes we can anticipate in the practice of medicine in the near future. Despite their promise, they pose challenges for introduction into the healthcare sector in South Africa (SA), including: (i) that they are technologically demanding and their manufacture is resource intensive; (ii) that the regulatory system is underdeveloped and likely to be challenged by ethical, legal and social requirements that accompany these new therapies; and (iii) that costs are likely to be prohibitive, at least initially, and before economies of scale take effect. Investment should be made into finding novel and innovative ways to introduce these therapies into SA sooner rather than later to ensure that SA patients are not excluded from these exciting new opportunitie
Comparative Fate of Chemically Dispersed and Beached Crude Oil in Subtidal Sediments of the Arctic Nearshore
A three-year investigation was conducted to examine the incorporation of petroleum hydrocarbons (PHC) into subtidal sediments following experimental releases of oil during the Baffin Island Oil Spill (BIOS) Project experiments. The concentrations of PHC were determined by synchronous scanning UV/Fluorescence spectroscopy, while the composition of residual saturated and aromatic hydrocarbons was determined by gas chromatography and gas chromatographic mass spectrometry. ... The eroding oil from the Bay 11 beach was compositionally quite heterogeneous, with weathered, biodegraded oil, as well as relatively unweathered oil, found on the beach and in the offshore sediments. Biodegradation of oil appeared to be restricted to the beached oil, with no significant degradation apparently occurring subtidally. After two years, the offshore oil residues still contained low molecular weight alkanes as well as alkylated naphthalenes. The situation in Bay 9, where chemically dispersed oil was discharged near the bottom, was quite different. In spite of a large water column exposure, the bottom sediments never contained more than 10 micro g/g of oil. Of this amount of oil, a significant fraction (20%) of the PHC was initially associated with the surface flocculent layer. Levels of oil in the Bay 9 sediments were on the order of 1-3 micro g/g one year after the release. Sediment PHC levels in the other less exposed bays (Bays 10 and 7) never exceeded 3 micro g/g.Key words: BIOS, experimental oil spill, petroleum hydrocarbons, arctic sediments, oil pollutionMots clés: BIOS, déversement de pétrole expérimental, hydrocarbures pétroliers, sédiments arctiques, pollution par le pétrol
Prevalence and correlates of diphtheria toxoid antibodies in children and adults in Israel
ABSTRACTA seroepidemiological study was performed to evaluate immunity to diphtheria and to determine the correlates of diphtheria toxoid antibody levels among children and adults in Israel. In total, 3185 sera from an age-stratified sample of children and adults, obtained in 2000–2001, were tested for diphtheria toxoid antibodies by an in-house double-antigen ELISA. A level of ≤0.01 IU /mL (no immune protection or seronegativity) was found in 168 (5.3%) of the 3185 subjects, 639 (20.1%) had antibody levels of 0.011–0.099 IU /mL (basic immunity or low seropositivity), and 2378 (74.7%) had antibody levels ≥0.1 IU /mL (full protection or seropositivity). Seronegativity increased significantly in subjects aged >50 years, reaching levels of 9.7%, 12.6% and 18.9% in the groups aged 50–54, 55–59 and >60 years, respectively (p 0.001), with rates of basic immunity following a similar pattern. Subjects born abroad had higher seronegativity rates than those born in Israel (7.7%vs. 4.9%; p 0.019). No difference in diphtheria toxoid antibody levels was found according to other demographical variables, such as gender, Jewish or Arab ethnicity, urban or rural settlements, and the subjects’ place of residence. The level of immunity to diphtheria among children and adults in Israel was satisfactory, with the exception of individuals aged >50 years. The risk of diphtheria outbreaks is low, but sporadic cases may occur among individuals lacking basic immunity against the disease
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