How does geological heterogeneity control floodplain groundwater dynamics?

Upland floodplains provide an important function in regulating river flows and controlling the coupling of hillslope runoff with rivers. A floodplain in an upland area of the River Tweed catchment, Scotland, was characterised using geophysics, 3D geological mapping, hydrogeological testing and geochemical sampling, and monitored from September 2011 to February 2013 for variations in groundwater levels, river stage, soil moisture and meteorological parameters, including a period of nine months of exceptionally high rainfall. The floodplain contains an unconsolidated, permeable alluvial and glaciofluvial aquifer 8 to 15 m thick, with transmissivity 50 to 1000 m2/d, which is coupled to the hillslope by permeable solifluction deposits. The floodplain aquifer is a significant store of, and conduit for, catchment water. It gains recharge from the river and the adjacent hillslope, transmitting groundwater downstream and acting as a buffer to restrict water flowing from the hillslope from directly entering the river. Floodplain groundwater level fluctuations are driven primarily by changes in river level and the propagation of pressure waves through the floodplain aquifer. There is significant lateral variation in floodplain groundwater response. Most of the floodplain aquifer is hydraulically connected to the river, but groundwater at the edge of the floodplain is strongly controlled by hillslope sub-surface flow. The geological structure and lithology of the hillslope-floodplain transition is an important hydrological control. It can enhance the influence of subsurface hillslope runoff to the floodplain, which has implications for runoff modelling, flood prevention interventions on hillslopes aimed at reducing runoff, and development at floodplain edges. Vertical heterogeneity in hydrological properties within the floodplain aquifer alters hydrological response, causing different depths of the floodplain to respond differently to hillslope and river inputs. These vertical variations need to be better taken into account in floodplain and hillslope-floodplain studies. This research demonstrates the importance of understanding the 3D geology and hydrogeology of floodplains in order to advance catchment research and effective flood management measures

Groundwater : meltwater interaction in a proglacial aquifer

Groundwater plays a significant role in the hydrology of active glacial catchments, with evidence that it may buffer changes in meltwater river flow and partially compensate for glacial loss. However, to date there has been little direct research into the hydrogeology and groundwater dynamics of proglacial aquifers. Here we directly investigate the three dimensional nature of a proglacial sandur (floodplain) aquifer in SE Iceland, using hydrogeological, geophysical, hydrological and stable isotopic techniques, and provide evidence of groundwater-melt water dynamics over three years. We show that the proglacial sandur forms a thick (at least 50-100 m), high permeability (transmissivity up to 2500 m2/day) aquifer, extending over an area of approximately 6 km2. At least 35 million m3 of groundwater is stored in the aquifer, equivalent to ~23-28% of total annual river flow through the catchment. The volume of mean annual groundwater flow through the aquifer is at least 0.1-1 m3/sec, equivalent to ~10-20% of mean annual river flow. Groundwater across the aquifer is actively recharged from local precipitation and strongly influenced by individual rainfall events and seasonal precipitation. Glacial meltwater influence on groundwater also occurs in a zone extending from 20-500 m away from the meltwater river, for at least 3km down-sandur, and to at least 15 m deep. Within this zone summer recharge from the river to groundwater occurs when meltwater river flows are high, maintaining high summer groundwater levels compared to winter levels; and groundwater temperature and chemistry are strongly influenced by meltwater. Beyond this zone there is no substantial meltwater influence on groundwater. From ~2 km down-sandur there is extensive groundwater discharge via springs, supporting semi-perennial streams that form distinct local ecosystems, and providing baseflow to the main meltwater river. This research indicates that predicted continued climate change-related reductions in glacier coverage and increases in precipitation are likely to increase the significance of groundwater storage as a water resource, and of groundwater discharges in maintaining environmental river flows in glacier catchments

A new strategic framework to structure Cumulative Impact Assessment (CIA)

In order to alleviate climate change consequences, UK governments are pioneering offshore energy developments with increasing commitment. The North Sea is a dynamic ecosystem with strong bottom-up/top-down natural and anthropogenic drivers facing rapid climate change impacts. Therefore, to ensure the compatibility of such large-scale developments with nature conservation obligations, cumulative effects need to be evaluated through cumulative impact assessments (CIA). However, by excluding climate change impacts, CIA lacks spatio-temporal appropriate baselines linking ecosystem components (e.g. physical indicators) to population dynamics which leads to uncertain predictions at populations levels. This study presents an overview of a framework for CIA using a holistic and pragmatic ecosystem approach based on spatio-temporal Bayesian network in order to identify pressure pathways, keystone components, ecosystem connectivity and resilience as well as population-level changes. We will also present potential fine-scale environmental monitoring solutions and data sources generated at MRED (Marine Renewable Energy Developments) site levels. Finally, we will discuss the usefulness of the two components that make up this framework: a database and an application of standardised shared tools that will pave the way to more transparent and multi-disciplinary collaborations. This framework will provide a multi-dimensional decision-making toolkit that would also lead towards more efficient SEAs (Strategic Environmental Assessment) as well as providing the ability to embed the CIAs of projects into regional and multinational schemes

Homocysteine in dogs with systemic inflammatory response syndrome

OBJECTIVES - To compare serum concentrations of homocysteine (Hcy) in dogs fitting the criteria for the systemic inflammatory response syndrome (SIRS) and healthy dogs, and compare these values to commonly measured B-vitamins. METHODS – Study dogs were classified into noninfectious SIRS or sepsis groups and blood was drawn on Day 1 of the patient’s hospitalization for the measurement of Hcy, folate and cobalamin concentrations. Hcy was measured in 51 clinically normal dogs to serve as the control group. RESULTS - A statistically significant difference was found between the Hcy concentrations of the healthy group when compared to noninfectious SIRS and sepsis groups. Hcy values were not correlated with folate, cobalamin or APPLEfast severity scores. Hcy concentrations were significantly lower in sick dogs when compared to the control group, which is dissimilar to the human population. CLINICAL SIGNIFCANCE - The clinical significance of Hcy changes in critically ill dogs is currently unknown.http://aac.asm.orghb2014ab201

Generalized pricing formulas for stochastic volatility jump diffusion models applied to the exponential Vasicek model

Path integral techniques for the pricing of financial options are mostly based on models that can be recast in terms of a Fokker-Planck differential equation and that, consequently, neglect jumps and only describe drift and diffusion. We present a method to adapt formulas for both the path-integral propagators and the option prices themselves, so that jump processes are taken into account in conjunction with the usual drift and diffusion terms. In particular, we focus on stochastic volatility models, such as the exponential Vasicek model, and extend the pricing formulas and propagator of this model to incorporate jump diffusion with a given jump size distribution. This model is of importance to include non-Gaussian fluctuations beyond the Black-Scholes model, and moreover yields a lognormal distribution of the volatilities, in agreement with results from superstatistical analysis. The results obtained in the present formalism are checked with Monte Carlo simulations.Comment: 9 pages, 2 figures, 1 tabl

Exposure to bioaerosols at open dumpsites: A case study of bioaerosols exposure from activities at Olusosun open dumpsite, Lagos Nigeria

Activities associated with the open dumping of municipal solid waste has the potential for greater impact on the environment and public health compared to other forms of waste-to-land treatment of such wastes. However, there is a lack of quantitative data on the exposure to bioaerosols from open dumpsites, hence impeding the development of effective interventions that would reduce the risk of respiratory symptoms among scavengers and waste workers at such dumpsites. This study investigated exposure to bioaerosols at Olusosun open dumpsite, Lagos Nigeria using three methodologies; (1) Conducting a cross-sectional survey on the respiratory health of the population on the dumpsite, (2) Measuring bioaerosol concentrations in the ambient air by measuring four bioaerosols indicator groups (total bacteria, gram-negative bacteria, Aspergillus fumigatus and total fungi) using a Anderson six stage impactor sampler, (3) Measuring activity related exposures to bioaerosols using an SKC button personal sampler. After a cross sectional health survey of 149 participants (waste workers, scavengers, middlemen, food vendors and business owners), smokers reported higher symptoms of chronic cough (21%) and chronic phlegm (15%) compared to non-smokers (chronic cough 15%, chronic phlegm 13%). Years of work > 5 years showed no statistically significant association with chronic phlegm (OR 1.2, 95% CI 0.4–3.4; p > 0.05) or asthma (OR 1.8, 95% CI 0.6–5.2; p > 0.05). At the 95th percentile, the concentration of total bacteria was the highest (2189 CFU/m3), then gram negative bacteria (2188 CFU/m3), total fungi (843 CFU/m3) and Aspergillus fumigatus (441 CFU/m3) after ambient air sampling. A comparison of the data showed that the activity-based sampling (undertaken using body worn personal sampler) had higher bioaerosols concentrations (104 –106 CFU/m3), i.e. 2–3 logs higher than those recorded from static ambient air sampling. Bioaerosol exposure was highest during scavenging activities compared to waste sorting and site supervision. Particle size distributions showed that 41%, 46%, 76% and 63% of total bacteria, gram-negative bacteria, Aspergillus fumigatus and total fungi respectively were of respirable sizes and would therefore be capable of penetrating deep into the respiratory system, posing a greater human health risk. This study has shown that exposure to bioaerosols can be associated with activities undertaken at open dumpsites and may contribute to the high prevalence of the chronic respiratory symptoms among the workers in such environments

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

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

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