Field validation of radon monitoring as a screening methodology for NAPL-contaminated sites

Screening methodologies aim at improving knowledge about subsurface contamination processes before expensive intrusive operations, i.e. drilling and core-sampling, well installation and development, sampling of groundwater and free-phase product, are implemented. Blind field tests carried out at a hydrocarbon storage and distribution center in NE Spain suggest that Rn monitoring can be effectively used to locate the boundaries of subsurface accumulations of NAPLs. Sixty seven measurements of Rn in soil air were performed with a SARAD RTM 2100 current-ionization alpha-particle spectrometer following a 10 m square grid. Reductions of 222Rn concentration above a pool of LNAPL due to the preferential partition of Rn into the organic phase were spatially analyzed and resolved to yield the surface contour of the NAPL source zone. This surface trace of the source zone agreed well with the extent and situation inferred from measurements of free-phase thickness taken at eight monitoring wells at the site. Moreover, the good repeatability (as measured by replicate measurements at the same sampling point) and spatial resolution of the technique suggest that the boundaries of the plume can be delineated at the sub-decametre level

Trends and geographic variation in adverse impacts of nitrogen use in Europe on human health, climate, and ecosystems: A review

This paper presents a review of the trends and geographic variation of impacts of reactive nitrogen (N) inputs on in Europe through impacts on air, soil and water quality. It illustrates those impacts, by assessing temporal and spatial variation in air, soil and water quality indicators and their exceedances of critical thresholds in view of impacts on human health, terrestrial and aquatic ecosystems, during 1990-2019. Trends are derived from regular inventory and monitoring data and from simulated trends in air quality using the EMEP model. Well quantified adverse impacts of increased N use are: (i) the effects on human health due to increased tropospheric concentrations of NOx and ozone, and N-induced increases in fine particulate matter, (ii) the contribution of N2O to climate change and stratospheric ozone depletion, (iii) the loss of plant and faunal diversity both in terrestrial and aquatic ecosystems via direct and soil mediated impacts, (iv) the acidification of forest soils, with impacts on tree forest nutrition, tree growth and tree vitality, and (v) the eutrophication of marine ecosystems, and associated biodiversity loss and occurrence of harmful algae blooms. Over the period 1990-2019, N inputs to agriculture stayed relatively constant, but the emissions of ammonia (NH3) decreased by 27%, while emissions of nitrogen oxides (NOx) decreased by 57%. In response to those reductions, concentrations of NOx, and of N in particulate matter also declined, although less than 50%. In contrast, the reduction in NOx-induced ozone concentrations and ozone related indicators (AOT40, SOMO35 and POD) was much less (ca 15-20%). Exceedances of critical ozone concentrations for human health and of critical AOT40 and POD vales for vegetation reduced in a similar order of magnitude. Despite decreasing NH3 emissions, NH3 concentrations showed a slight and steady increase from 1995 onwards, due to the large reduction in SOx emissions. Nitrogen deposition and exceedances of critical N loads for terrestrial ecosystems decreased by ca 60%, but the area exceeding critical N loads only reduced by ca 10%. Unlike N, the area exceeding critical acid loads has declined by more than 90% due to high reduction in SOx and NOx emissions. Trends in nitrate (NO3) concentrations in groundwater varied across Europe, but showed overall limited changes over the last two decades. However, N concentrations in surface water and the area exceeding critical levels in view of aquatic biodiversity has decreased and the same holds for N concentrations in coastal regions. Nevertheless, the eutrophication condition of coastal waters has overall not improved due to adverse impacts of elevated phosphorus inputs. Finally the negative impacts of N induced N2O emissions on climate are estimated to be outweighed by the positive effects of N induced CO2 sequestration, mainly in forests, and this holds for the whole period 1990-2019. Nitrogen hotspots, being areas with high exceedances in critical levels and loads of N compounds in air and water, are concentrated in intensive agricultural areas with high livestock densities and in urban region with strong industrial and traffic activities. Cost-benefit analysis shows that environmental costs of reactive N release to the environment are substantial and tend to exceed the direct economic benefits for agriculture. Given the relevance of N for safeguarding food production it is key to develop integrated and targeted plant nutrition strategies following a food system approach and practices that minimize trade-offs between productivity and the environment. In addition, targeted strategies to further reduce NOx emissions are needed to reduce air quality related health and biodiversity impacts

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Controlling the structure of supramolecular fibre formation for benzothiazole based hydrogels with antimicrobial activity against methicillin resistant Staphylococcus aureus

Antimicrobial resistance is one of the greatest threats to human health. Gram-positive methicillin resistant Staphylococcus aureus (MRSA), in both its planktonic and biofilm form, is of particular concern. Herein we identify the hydrogelation properties for a series of intrinsically fluorescent, structurally related supramolecular self-associating amphiphiles and determine their efficacy against both planktonic and biofilm forms of MRSA. To further explore the potential translation of this hydrogel technology for real-world applications, the toxicity of the amphiphiles was determined against the eukaryotic multicellular model organism, Caenorhabditis elegans. Due to the intrinsic fluorescent nature of these supramolecular amphiphiles, material characterisation of their molecular self-associating properties included; comparative optical density plate reader assays, rheometry and widefield fluorescence microscopy. This enabled determination of amphiphile structure and hydrogel sol dependence on resultant fibre formation

Design and construction of the MicroBooNE detector

This paper describes the design and construction of the MicroBooNE liquid argon time projection chamber and associated systems. MicroBooNE is the first phase of the Short Baseline Neutrino program, located at Fermilab, and will utilize the capabilities of liquid argon detectors to examine a rich assortment of physics topics. In this document details of design specifications, assembly procedures, and acceptance tests are reported

Charged-particle distributions in √s=13 TeV pp interactions measured with the ATLAS detector at the LHC

Charged-particle distributions are measured in proton–proton collisions at a centre-of-mass energy of 13 TeV, using a data sample of nearly 9 million events, corresponding to an integrated luminosity of 170 μb−1170 μb−1, recorded by the ATLAS detector during a special Large Hadron Collider fill. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the dependence of the mean transverse momentum on the charged-particle multiplicity are presented. The measurements are performed with charged particles with transverse momentum greater than 500 MeV and absolute pseudorapidity less than 2.5, in events with at least one charged particle satisfying these kinematic requirements. Additional measurements in a reduced phase space with absolute pseudorapidity less than 0.8 are also presented, in order to compare with other experiments. The results are corrected for detector effects, presented as particle-level distributions and are compared to the predictions of various Monte Carlo event generators