Aerial strategies advance volcanic gas measurements at inaccessible, strongly degassing volcanoes.

Volcanic emissions are a critical pathway in Earth's carbon cycle. Here, we show that aerial measurements of volcanic gases using unoccupied aerial systems (UAS) transform our ability to measure and monitor plumes remotely and to constrain global volatile fluxes from volcanoes. Combining multi-scale measurements from ground-based remote sensing, long-range aerial sampling, and satellites, we present comprehensive gas fluxes-3760 ± [600, 310] tons day-1 CO2 and 5150 ± [730, 340] tons day-1 SO2-for a strong yet previously uncharacterized volcanic emitter: Manam, Papua New Guinea. The CO2/ST ratio of 1.07 ± 0.06 suggests a modest slab sediment contribution to the sub-arc mantle. We find that aerial strategies reduce uncertainties associated with ground-based remote sensing of SO2 flux and enable near-real-time measurements of plume chemistry and carbon isotope composition. Our data emphasize the need to account for time averaging of temporal variability in volcanic gas emissions in global flux estimates.

Determining the sources of nutrient flux to water in headwater catchments: Examining the speciation balance to inform the targeting of mitigation measures.

Diffuse water pollution from agriculture (DWPA) is a major environmental concern, with significant adverse impacts on both human and ecosystem health. However, without an appropriate understanding of the multiple factors impacting on water, mitigation measures cannot be targeted. Therefore, this paper addresses this gap in understanding, reporting the hydrochemical monitoring evidence collected from the UK Government's Demonstration Test Catchments (DTC) programme including contrasting chalk and clay/mudstone catchments. We use data collected at daily and sub-daily frequency over multiple sites to address: (1) How does the behaviour of the full range of nitrogen (N) species and phosphorus (P) fractions vary? (2) How do N species and P fractions vary inter- and intra-annually? (3) What do these data indicate about the primary pollution sources? And (4) which diffuse pollution mitigation measures are appropriate in our study landscapes? Key differences in the rates of flux of nutrients were identified, dependent on catchment characteristics. Full N speciation and P fractionation, together with dissolved organic carbon (DOC) enabled identification of the most likely contributing sources in each catchment. Nitrate (NO3-N) was the dominant N fraction in the chalk whereas organic and particulate N comprised the majority of the load in the clay/mudstone catchments. Despite current legislation, orthophosphate (PO4-P) was not found to be the dominant form of P in any of the catchments monitored. The chalk sub-catchments had the largest proportion of inorganic/dissolved organic P (DOP), accompanied by episodic delivery of particulate P (PP). Contrastingly, the clay/mudstone sub-catchments loads were dominated by PP and DOP. Thus, our results show that by monitoring both the inorganic and organic fractions a more complete picture of catchment nutrient fluxes can be determined, and sources of pollution pin-pointed. Ultimately, policy and management to bring nutrient impacts under control will only be successful if a multi-stressor approach is adopted.

Major agricultural changes required to mitigate phosphorus losses under climate change.

Phosphorus losses from land to water will be impacted by climate change and land management for food production, with detrimental impacts on aquatic ecosystems. Here we use a unique combination of methods to evaluate the impact of projected climate change on future phosphorus transfers, and to assess what scale of agricultural change would be needed to mitigate these transfers. We combine novel high-frequency phosphorus flux data from three representative catchments across the UK, a new high-spatial resolution climate model, uncertainty estimates from an ensemble of future climate simulations, two phosphorus transfer models of contrasting complexity and a simplified representation of the potential intensification of agriculture based on expert elicitation from land managers. We show that the effect of climate change on average winter phosphorus loads (predicted increase up to 30% by 2050s) will be limited only by large-scale agricultural changes (e.g., 20-80% reduction in phosphorus inputs).The impact of climate change on phosphorus (P) loss from land to water is unclear. Here, the authors use P flux data, climate simulations and P transfer models to show that only large scale agricultural change will limit the effect of climate change on average winter P loads in three catchments across the UK.

Using hysteresis analysis of high-resolution water quality monitoring data, including uncertainty, to infer controls on nutrient and sediment transfer in catchments.

A large proportion of nutrients and sediment is mobilised in catchments during storm events. Therefore understanding a catchment's hydrological behaviour during storms and how this acts to mobilise and transport nutrients and sediment to nearby watercourses is extremely important for effective catchment management. The expansion of available in-situ sensors is allowing a wider range of water quality parameters to be monitored and at higher temporal resolution, meaning that the investigation of hydrochemical behaviours during storms is increasingly feasible. Studying the relationship between discharge and water quality parameters in storm events can provide a valuable research tool to infer the likely source areas and flow pathways contributing to nutrient and sediment transport. Therefore, this paper uses 2 years of high temporal resolution (15/30 min) discharge and water quality (nitrate-N, total phosphorus (TP) and turbidity) data to examine hysteretic behaviour during storm events in two contrasting catchments, in the Hampshire Avon catchment, UK. This paper provides one of the first examples of a study which comprehensively examines storm behaviours for up to 76 storm events and three water quality parameters. It also examines the observational uncertainties using a non-parametric approach. A range of metrics was used, such as loop direction, loop area and a hysteresis index (HI) to characterise and quantify the storm behaviour. With two years of high resolution information it was possible to see how transport mechanisms varied between parameters and through time. This study has also clearly shown the different transport regimes operating between a groundwater dominated chalk catchment versus a surface-water dominated clay catchment. This information, set within an uncertainty framework, means that confidence can be derived that the patterns and relationships thus identified are statistically robust. These insights can thus be used to provide information regarding transport processes and biogeochemical processing within river catchments.

A novel framework for discharge uncertainty quantification applied to 500 UK gauging stations.

A generalized framework for discharge uncertainty estimation is presentedAllows estimation of place-specific discharge uncertainties for many catchmentsLocal conditions dominate in determining discharge uncertainty magnitudes.

Analysis of enoxaparin dose titration at a large, tertiary teaching facility.

Therapeutic drug monitoring of enoxaparin with antifactor Xa levels (AXALs) is recommended in some populations; however, the approach to dose titration is poorly described. Our study at a large, tertiary teaching facility examined the dose response to titration of enoxaparin based on AXAL. Patients from 2008 to 2012 receiving enoxaparin were included, provided 2 or more steady state AXAL were obtained within 30 days and that the enoxaparin was prescribed for treatment rather than prophylaxis. The primary outcome was the percentage of dose change required to obtain goal range AXAL following dose titration. Eighty-seven patients were available for analysis with the following key characteristics: renal dysfunction during treatment 72%, obesity 8%, and solid organ transplant 26%. Initial goal AXAL was attained in 27 (31%) patients, and ultimately 54 (62%) patients achieved goal AXAL. Of the 31 patients who had initial AXAL above goal, 13 (42%) patients reached goal with a median dose decrease of 24%. In the 29 patients who had an initial AXAL below goal, 11 (38%) achieved therapeutic AXAL with a median dose increase of 16%. The AXAL monitoring can guide enoxaparin titration with subtherapeutic or supratherapeutic AXAL and an increase or decrease of roughly 20% is suggested as an initial change.

A novel application of natural fluorescence to understand the sources and transport pathways of pollutants from livestock farming in small headwater catchments.

This paper demonstrates the application of a low-cost and rapid natural fluorescence technique for tracing and quantifying the transport of pollutants from livestock farming through a small headwater catchment. Fluorescence intensities of Dissolved Organic Matter (DOM) present in different pollutant sources and drainage waters in the Den Brook catchment (Devon, UK) were monitored through storm events occurring between January 2007 and June 2008. Contrasting fluorescence signals from different sources confirmed the technique's usefulness as a tracer of pollutants from livestock farming. Changes in fluorescence intensities of drainage waters throughout storm events were used to assess the dynamics of key pollutant sources. The farmyard area of the catchment studied was shown to contribute polluted runoff at the onset of storm events in response to only small amounts of rain, when flows in the Den Brook first-order channel were low. The application of slurry to a field within the catchment did not elevate the fluorescence of drainage waters during storm events suggesting that when slurry is applied to undrained fields the fluorescent DOM may become quickly adsorbed onto soil particles and/or immobilised through bacterial breakdown. Fluorescence intensities of drainage waters were successfully combined with discharge data in a two component mixing model to estimate pollutant fluxes from key sources during the January 2007 storm event. The farmyard was shown to be the dominant source of tryptophan-like material, contributing 61-81% of the total event flux at the catchment outlet. High spatial and temporal resolution measurements of fluorescence, possibly using novel in-situ fluorimeters, may thus have great potential in quickly identifying and quantifying the presence, dynamics and sources of pollutants from livestock farming in catchments.

New insights in the dihydroxybenzenes-driven Fenton reaction: electrochemical study of interaction between dihydroxybenzenes and Fe(III).

It has been reported that the dihydroxybenzene (DHB) driven Fenton reaction is more efficient to degrade recalcitrant substrates than the simple Fenton reaction. The enhanced reactivity of the DHB driven Fenton reaction is not clear, but it could be explained by the formation of oxidant species different from the ones formed by classical Fenton reaction or by the shift of the redox potential of the complex formed by DHB and Fe(III). The redox reaction between Fe(III) and the DHBs 1,2-dihydroxybenzene (catechol, CAT), 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DHBA), and 1,2-dihydroxy-3,5-benzenedisulfonate (TIRON) was studied by cyclic voltammetry to better understand the enhanced reactivity of the DHB driven Fenton reaction. It was determined that the amount of Fe(II) produced by the redox reaction between Fe(III) and DHBs was insufficient to explain the enhanced reactivity. Cyclic voltammograms (CV) of the DHBs/Fe(III) systems show a quasi-reversible or irreversible behavior and also shifting and splitting the anodic peaks. This effect can be related to DHBs oxidation by Fe(III), but not to a real interaction.

Assessing catchment-scale erosion and yields of suspended solids from improved temperate grassland.

This paper quantifies the yields of suspended solids (SS) from a headwater catchment managed as improved temperate grassland, providing the first direct, catchment-scale evidence of the rates of erosion from this land-use in the UK and assessing the threat posed to aquatic ecosystems. High-resolution monitoring of catchment hydrology and the concentrations of SS and volatile organic matter (VOM) were carried out in the first-order channel of the Den Brook headwater catchment in Devon (UK) during the 2006-2007 hydrological season. The widely used 'rating curve' (discharge-concentration) approach was employed to estimate yields of SS, but as demonstrated by previous researchers, this study showed that discharge is a poor predictor of SS concentrations and therefore any yields estimated from this technique are likely to be highly uncertain. Nevertheless, for the purpose of providing estimates of yields that are comparable to previous studies on other land uses/sources, this technique was adopted albeit in an uncertainty-based framework. The findings suggest that contrary to the common perception, grasslands can be erosive landscapes with SS yields from this catchment estimated to be between 0.54 and 1.21 t ha(-1) y(-1). In terms of on-site erosion problems, this rate of erosion does not significantly exceed the commonly used 'tolerable' threshold in the UK ( approximately 1 t ha(-1) y(-1)). In terms of off-site erosion problems, it is argued here that the conventional expression of SS yield as a bulk annual figure has little relevance to the water quality and ecological status of surface waters and therefore an alternative technique (the concentration-frequency curve) is developed within this paper for the specific purpose of assessing the ecological threat posed by the delivery of SS into surface waters. This technique illustrates that concentrations of SS recorded at the catchment outlet frequently exceed the water quality guidelines, such as those of the EU Freshwater Fisheries Directive (78/659/EC), and pose a serious threat to aquatic organisms. It is suggested that failure to recognise improved temperate grasslands as a potential source of particulate material could result in the non-compliance of surface waters to water quality guidelines, deterioration of ecological status and failure of water quality remediation measures.

Genetic Diversity of Prunus necrotic ringspot virus Isolates Within a Cherry Orchard in New York.

A survey for Prunus necrotic ringspot virus (PNRSV) in an orchard of Prunus cerasus cv. Montmorency and Prunus avium cv. Hedelfingen in New York by enzyme-linked immunosorbent assay indicated an eightfold higher infection rate in sour cherry (33%, 32 of 96) than in sweet cherry (4%, 6 of 136) trees. The presence of PNRSV was confirmed by reverse transcription-polymerase chain reaction and amplification of the coat protein (CP) gene in total RNA from infected leaf tissue. Latent infection was prevalent in the majority of trees infected (87%, 33 of 38), while a few of them exhibited shock symptoms or had severely reduced growth (13%, 5 of 38). Asymptomatic PNRSV-infected trees clustered in spatial proximity to symptomatic trees. Sequence analysis of the CP gene (675 bp) indicated a population structure consisting of one predominant molecular variant for 10 isolates and six minor molecular variants for seven isolates. A high sequence identity was found between the CP gene of PNRSV isolates from cherry trees and other isolates from diverse hosts and various geographic origins at the nucleotide and amino acid levels (88 to 100%). Phylogenetic analyses showed a clustering of PNRSV isolates from cherry trees in New York in the predominant group PV-96.

Rethinking the contribution of drained and undrained grasslands to sediment-related water quality problems.

Grass vegetation has been recommended for use in the prevention and control of soil erosion because of its dense sward characteristics and stabilizing effect on the soil. A general assumption is that grassland environments suffer from minimal soil erosion and therefore present little threat to the water quality of surface waters in terms of sediment and sorbed contaminant pollution. Our data question this assumption, reporting results from one hydrological year of observations on a field-experiment monitoring overland flow, drain flow, fluxes of suspended solids, total phosphorus (TP), and molybdate-reactive phosphorus (<0.45 mum) in response to natural rainfall events. During individual rainfall events, 1-ha grassland lysimeters yield up to 15 kg of suspended solids, with concentrations in runoff waters of up to 400 mg L(-1). These concentrations exceed the water quality standards recommended by the European Freshwater Fisheries Directive (25 mg L(-1)) and the USEPA (80 mg L(-1)) and are beyond those reported to have caused chronic effects on freshwater aquatic organisms. Furthermore, TP concentrations in runoff waters from these field lysimeters exceeded 800 mug L(-1). These concentrations are in excess of those reported to cause eutrophication problems in rivers and lakes and contravene the ecoregional nutrient criteria in all of the USA ecoregions. This paper also examines how subsurface drainage, a common agricultural practice in intensively managed grasslands, influences the hydrology and export of sediment and nutrients from grasslands. This dataset suggests that we need to rethink the conceptual understanding of grasslands as non-erosive landscapes. Failure to acknowledge this will result in the noncompliance of surface waters to water quality standards.

Photocatalyzed degradation of flumequine by doped TiO2 and simulated solar light.

Titanium dioxide was obtained in its pure form (TiO2) and in the presence of urea (u-TiO2) and thiourea (t-TiO2) using the sol-gel technique. The obtained powders were characterized by BET surface area analysis, Infrared Spectroscopy, Diffuse Reflectance Spectroscopy and the Rietveld refinement of XRD measurements. All the prepared catalysts show high anatase content (>99%). The a and b-cell parameters of anatase increase in the order TiO2u-TiO2>TiO2. The photocatalytic activities of the samples were determined on flumequine under solar-simulated irradiation. The most active catalysts were u-TiO2 and t-TiO2, reaching values over 90% of flumequine degradation after 15 min irradiation, compared with values of 55% for the pure TiO2 catalyst. Changing simultaneously the catalyst amount (t-TiO2) and pH, multivariate analysis using the response surface methodology was used to determine the roughly optimal conditions for flumequine degradation. The optimized conditions found were pH below 7 and a catalyst amount of 1.6 g L(-1).

Using a second-order polynomial model to determine the optimum dregs/bark ratio for industrial-biosolid composting: the initial conditioning stage.

Increasing pulp industry production has generated additional solid waste (i.e. biological sludge, dregs, etc.) and therefore an increasing disposal problem. On the other hand, composting is emerging as an interesting alternative for the disposal of residues. The objective of this study was to evaluate the physical and chemical properties of sludge, dregs and bark and the effect on their initial conditioning stage prior to composting, using pine chips as bulking agent. After their characterization, these solid wastes were combined in different mixture proportions defined by a 32 experimental design based on the response surface methodology (RSM), in which 18 observations were required for the independent variables (dregs and bark) and the C: N ratio, moisture content and pH were the dependent variables. The characterization indicated that the dregs have alkaline properties with the presence of some essential plant nutrients, such as phosphorous (0.37%), potassium (0.76%), magnesium (1.4%) and calcium (27%). The combination of the macronutrients (phosphorous: 0.39%, potassium: 0.24%, calcium: 1.7%, magnesium: 0.44%) and micronutrients such as ferrous material (0.47%) and zinc (0.12%) found in the sludge suggest a promising alternative despite the potential problem due to the high pH of the dregs. The RSM design indicated a feasible region that satisfied the optimal dregs: bark ratio of 0.25 without exceeding the addition of 12.5% dregs, due to the alkaline properties of these inorganic wastes and the quadratic influence over the C:N ratio. The experimental results indicated that the composting process of dregs, bark and sludge is technically suitable, although the use of a rapidly available C source needs to be evaluated.

Coupling of photocatalytic and biological reactors to remove EDTA-Fe from aqueous solution.

Degradation of 2.5 mM EDTA-Fe solution was performed in a coupled photocatalytic-biological reactor. The system consists of a photochemical annular reactor filled with TiO2 immobilized on glass Raschig rings coupled with an activated sludge continuous reactor. Around 50% of EDTA degradation was reached after 150 min irradiation. Simultaneously a four-fold increase in biodegradability, measured as BOD5/COD ratio, was observed. The activated sludge is not capable to degrade the complex EDTA-Fe but it removed partially the COD and efficiently the BOD5 of the photochemically treated solution.

Fe(III)-EDTA complex abatement using a catechol driven Fenton reaction combined with a biological treatment.

A combined chemical oxidation (catechol-driven Fenton reaction) followed by a biological treatment was used to degrade Fe(III)-EDTA (1.34 mM). The chemical treatment was inspired in fungal non-enzymatic wood rot mechanisms that use dihydroxybenzens in order to promote the Fenton reaction to breakdown wood structures. This chemical pre-oxidation used catechol (50 microM) and H202 (20 mM) and the reaction products were identified by GC-MS. In addition, a biological treatment was coupled using the baker's yeast Saccharomyces cerevisiae. The combined chemical biological treatment achieved 100% EDTA degradation, 68 % total organic carbon removal and 90% iron removal.

Degradation of recalcitrant compounds by catechol-driven Fenton reaction.

Dihydroxybenzenes are able to reduce Fe(III) and promote the Fenton reaction in the presence of H2O2. The catechol/Fe(III)/H2O2 system has been successfully used to degrade different compounds, being more efficient than the Fe(II)-Fenton reaction. In this paper the possibilities for using the catechol-driven Fenton reaction to degrade recalcitrant compounds such as the Fe(III)-EDTA complex and veratryl alcohol are reviewed.

Reactive dyes decolouration by TiO2 photo-assisted catalysis.

The photocatalytic degradation of three reactive azo dyes (yellow-2, orange-16 and red-2) and one anthraquinone reactive dye (blue-19) was studied. The reactions were carried out in a reactor with recirculation using TiO2 immobilised on glass Raschig rings (system A) and compared with a batch system using the catalyst in aqueous suspension (system B). Both reaction systems were irradiated with a 125 W, lambda > 254 nm lamp. The suspended TiO2 system was also studied using a 125 W 360 nm lamp (system C). Kinetic studies indicated a rapid colour removal, following the order B > A > C. The same trend was observed in COD and TOC removal profiles. The energy consumption per order of magnitude of catalytic degradation of the dyes was lower in the batch reactor (system B) than in the reactor with recirculation and immobilised TiO2 (system A).

Dihydroxybenzenes: driven Fenton reactions.

Different compounds that reduce Fe(III) and that simultaneously increase the oxidation potential of the H2O2/Fe2+ system, have been evaluated. In this work, the improving of Fenton reactions by 2,3-dihydroxybenzoic acid (2,3-DHBA), 3,4-dihydroxybenzoic acid (3,4-DHBA) or 1,2-dihydroxybenzene (CAT) were studied. The three compounds are able to reduce Fe(III) to Fe(II), but the kinetic results depend on the method used to determine the Fe(II) ion. The dihydroxybenzenes (DHBs) degrades veratryl alcohol (VA), a lignin model compound, to a greater extent than observed in a typical Fenton reaction. The rate of VA degradation was associated with the duration of the chemiluminescence (CAT > 2,3-DHBA > 3,4-DHBA) and not with the sum of integrated counts. The treatment of a cellulose pulp bleaching effluent with DHBs/Fe(III)/H2O2 was evaluated by analyzing their depolymerization at pH 4 and 7 through molecular mass distribution determinations.

The palliative medicine extended standardized patient scenario: a preliminary report.

An extended standardized patient scenario (ESPS) is described that utilizes standardized patients (SPs) in palliative care education of medical students and residents. The goals of the ESPS will be to: (1) improve physician communications skills in regard to breaking bad news and end-of-life care; (2) integrate evidence-based medicine into patient recommendations; and (3) enhance clinical skills in the practice of palliative medicine, particularly the evaluation and management of total suffering. The main features of the ESPS include a single SP scenario that is presented over several sessions, portraying an extended period in the patient's life. The ESPS requires little in the way of equipment, but is labor intensive. The ESPS is a promising modality that deserves further scrutiny and outcomes research.