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1.
Int J Technol Assess Health Care ; 37: e6, 2020 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-33317647

RESUMEN

Patient and public involvement in Health Technology Assessment (HTA) is gaining increased interest among research and policy communities. Patients' organizations represent an important link between individual patients and the health system. Social theories are increasingly being used to explain doctor-patient-system interactions, expanding understanding beyond the mere clinical perspective. In this sense, patient involvement in HTA can also be considered through the Habermas's theory of communicative action. From a Habermasian perspective, HTA as part of the instrumental rationality contributes to an increased efficiency of resource use within the system; however, such rationalization threatens to colonize the lifeworld by making it "increasingly state administered with attenuated possibilities for communicative action as a result of the commercialization and rationalization in terms of immediate returns." Using Habermasian system/lifeworld framework, this paper explores opportunities and obstacles to patient involvement in HTA, whereby trying to understand current and possible roles of patients' organizations as a mediating force between HTA as a function of the system and the lifeworld represented by patients.


Asunto(s)
Participación del Paciente/métodos , Teoría Social , Evaluación de la Tecnología Biomédica/organización & administración , Comunicación , Participación de la Comunidad/métodos , Eficiencia Organizacional , Humanos , Rol Profesional
2.
J Environ Manage ; 231: 146-154, 2019 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-30340134

RESUMEN

Metalled roads have been shown to act as a major pathway for land-to-river sediment transfer, but there currently exists limited research into mitigation solutions to tackle this pollution source. The aim of this study was to assess the effectiveness of three roadside constructed wetlands, installed in September 2016, at reducing sediment enrichment in a tributary of the River Wensum, UK. Two wetland designs were trialled (linear and 'U-shaped'), both of which act as settling ponds to encourage entrained sediment to fall out of suspension and allow cleaner water to discharge into the river. Wetland efficiency was monitored through automated, high-resolution (30 min) turbidity probes installed upstream and downstream of the wetlands, providing a near-continuous record of river turbidity before (October 2011-August 2016) and after (November 2016-February 2018) installation. This was supplemented by lower resolution monitoring of the wetland inflows and outflows, as well as an assessment of sediment and nutrient accumulation rates within the linear wetland. Results revealed median river sediment concentrations decreased up to 14% after wetland construction and sediment load decreased by up to 82%, although this was largely driven by low river discharge post-installation. Median sediment concentrations discharging from the linear wetland (7.2 mg L-1) were higher than the U-shaped wetland (3.9 mg L-1), confirming that a longer flow pathway through wetlands can improve sediment retention efficiency. After 12 months of operation, the linear wetland had retained 7253 kg (305 kg ha-1 y-1) of sediment, 11.6 kg (0.5 kg ha-1 y-1) of total phosphorus, 29.7 kg (1.3 kg ha-1 y-1) of total nitrogen and 400 kg (17 kg ha-1 y-1) of organic carbon. This translates into mitigated pollutant damage costs of £392 for sediment, £148 for phosphorus and £13 for nitrogen, thus giving a combined total mitigated damage cost of £553 y-1. With the linear wetland costing £3411 to install and £145-182 y-1 to maintain, this roadside constructed wetland has an estimated payback time of 8 years, making it a cost-effective pollution mitigation measure for tackling sediment-enriched road runoff that could be widely adopted at the catchment-scale.


Asunto(s)
Ríos , Humedales , Carbono , Nitrógeno , Fósforo
3.
Environ Sci Technol ; 51(1): 301-307, 2017 01 03.
Artículo en Inglés | MEDLINE | ID: mdl-27990802

RESUMEN

Agriculture is a major source of nitrous oxide (N2O) emissions, a potent greenhouse gas. While direct N2O emissions from soils have been widely investigated, indirect N2O emissions from nitrogen (N) enriched surface water and groundwater bodies are poorly understood. In this contribution, indirect N2O emissions from subsurface agricultural field drains and headwater streams were monitored over a two-year period (2013-2015) in an intensive arable catchment in eastern England. Indirect N2O emission factors for groundwater (EF5g) and surface runoff (EF5r) were calculated for both field drain and streamwater samples, respectively, using two approaches: the N2O-N/NO3-N ratio and the IPCC (2006) methodology. Mean EF5g values derived from the N2O-N/NO3-N ratio were 0.0012 for field drains and 0.0003 for streamwater. Using the IPCC (2006) methodology, the mean EF5g values were 0.0011 for field drains and 0.0001 for streamwater. Thus, EF values derived from both methods were below the current IPCC (2006) default value of 0.0025 and a downward revision to 0.0012 for EF5g and 0.0002 for EF5r is recommended. Such revision would halve current estimates of N2O emissions associated with nitrogen leaching and runoff from agriculture for both the UK and globally.


Asunto(s)
Óxido Nitroso , Ríos , Agricultura , Monitoreo del Ambiente , Suelo
4.
Environ Sci Technol ; 51(18): 10440-10448, 2017 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-28841017

RESUMEN

Indirect nitrous oxide (N2O) emissions from rivers are currently derived using poorly constrained default IPCC emission factors (EF5r) which yield unreliable flux estimates. Here, we demonstrate how hydrogeological conditions can be used to develop more refined regional-scale EF5r estimates required for compiling accurate national greenhouse gas inventories. Focusing on three UK river catchments with contrasting bedrock and superficial geologies, N2O and nitrate (NO3-) concentrations were analyzed in 651 river water samples collected from 2011 to 2013. Unconfined Cretaceous Chalk bedrock regions yielded the highest median N2O-N concentration (3.0 µg L-1), EF5r (0.00036), and N2O-N flux (10.8 kg ha-1 a-1). Conversely, regions of bedrock confined by glacial deposits yielded significantly lower median N2O-N concentration (0.8 µg L-1), EF5r (0.00016), and N2O-N flux (2.6 kg ha-1 a-1), regardless of bedrock type. Bedrock permeability is an important control in regions where groundwater is unconfined, with a high N2O yield from high permeability chalk contrasting with significantly lower median N2O-N concentration (0.7 µg L-1), EF5r (0.00020), and N2O-N flux (2.0 kg ha-1 a-1) on lower permeability unconfined Jurassic mudstone. The evidence presented here demonstrates EF5r can be differentiated by hydrogeological conditions and thus provide a valuable proxy for generating improved regional-scale N2O emission estimates.


Asunto(s)
Monitoreo del Ambiente , Óxido Nitroso , Ríos , Agua Dulce , Agua Subterránea
5.
J Am Chem Soc ; 138(1): 96-9, 2016 Jan 13.
Artículo en Inglés | MEDLINE | ID: mdl-26714195

RESUMEN

Water exhibits remarkable properties in confined spaces, such as nanometer-sized droplets where hundreds of water molecules are required for crystalline structure to form at low temperature due to surface effects. Here, we investigate how a single ion affects the crystallization of (H2O)n clusters with infrared photodissociation spectroscopy of size-selected La(3+)(H2O)n nanodrops containing up to 550 water molecules. Crystallization in the ion-containing nanodrops occurs at n ≥ 375, which is approximately 100 more water molecules than what has been reported for neutral water clusters. This frustration of crystallinity reveals that La(3+) disrupts the hydrogen-bonding network of water molecules located remotely from the ion, a conclusion that is supported by molecular dynamics simulations. Our findings establish that a trivalent ion can pattern the H-bond network of water molecules beyond the third solvation shell, or to a distance of ∼1 nm from the ion.

6.
J Environ Manage ; 181: 874-882, 2016 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-27397841

RESUMEN

Agricultural point source pesticide pollution arising from contaminated machinery washings and accidental spillages pose a significant threat to river water and groundwater quality. In this study, we assess the effectiveness of a three-stage on-farm biobed for treating pesticide contaminated wastewater from a large (20 km(2)) commercial arable estate. The facility consisted of an enclosed machinery wash-down unit (stage 1), a 49 m(2) lined compost-straw-topsoil biobed (stage 2), and a 200 m(2) drainage field with a trickle irrigation system (stage 3). Pesticide concentrations were analysed in water samples collected fortnightly between November 2013 and November 2015 from the biobed input and output sumps and from 20 porous pots buried at 45 cm and 90 cm depth within the drainage field. The results revealed that the biobed removed 68-98% of individual pesticides within the contaminated washings, with mean total pesticide concentrations reducing by 91.6% between the biobed input and output sumps. Drainage field irrigation removed a further 68-99% of individual pesticides, with total mean pesticide concentrations reducing by 98.4% and 97.2% in the 45 cm and 90 cm depth porous pots, respectively. The average total pesticide concentration at 45 cm depth in the drainage field (57 µg L(-1)) was 760 times lower than the mean concentration recorded in the input sump (43,334 µg L(-1)). There was no evidence of seasonality in the efficiency of biobed pesticide removal, nor was there evidence of a decline in removal efficiency over the two-year monitoring period. However, higher mean total pesticide concentrations at 90 cm (102 µg L(-1)) relative to 45 cm (57 µg L(-1)) depth indicated an accumulation of pesticide residues deeper within the soil profile. Overall, the results presented here demonstrate that a three-stage biobed can successfully reduce pesticide pollution risk from contaminated machinery washings on a commercial farm.


Asunto(s)
Granjas , Plaguicidas , Eliminación de Residuos Líquidos/métodos , Contaminantes Químicos del Agua , Riego Agrícola/instrumentación , Riego Agrícola/métodos , Agricultura/métodos , Diseño de Equipo , Residuos de Plaguicidas/análisis , Residuos de Plaguicidas/aislamiento & purificación , Plaguicidas/análisis , Plaguicidas/aislamiento & purificación , Suelo , Reino Unido , Eliminación de Residuos Líquidos/instrumentación , Aguas Residuales/análisis , Aguas Residuales/química , Contaminantes Químicos del Agua/análisis
7.
Phys Chem Chem Phys ; 17(24): 15963-75, 2015 Jun 28.
Artículo en Inglés | MEDLINE | ID: mdl-26028325

RESUMEN

Hydration of PbNO3(+) and SrNO3(+) with up to 30 water molecules was investigated with infrared photodissociation (IRPD) spectroscopy and with theory. These ions are the same size, yet the IRPD spectra of these ion pairs for n = 2-8 are significantly different. Bands in the bonded O-H region (∼3000-3550 cm(-1)) indicate that the onset of a second hydration shell begins at n = 5 for PbNO3(+) and n = 6 for SrNO3(+). Spectra for [PbNO3](+)(H2O)2-5 and [SrNO3](+)(H2O)3-6 indicate that the structures of clusters with Pb(ii) are hemidirected with a void in the coordinate sphere. A natural bond orbital analysis of [PbNO3](+)(H2O)5 indicates that the anisotropic solvation of the ion is due to a region of asymmetric electron density on Pb(ii) that can be explained by charge transfer from the nitrate and water ligands into unoccupied p-orbitals on Pb(ii). There are differences in the IRPD spectra of PbNO3(+) and SrNO3(+) with up to 25 water molecules attached. IR intensity in the bonded O-H region is blue-shifted by ∼50 cm(-1) in nanodrops containing SrNO3(+) compared to those containing PbNO3(+), indicative of a greater perturbation of the water H-bond network by strontium. The free O-H stretches of surface water molecules in nanodrops containing 10, 15, 20, and 25 water molecules are red-shifted by ∼3-8 cm(-1) for PbNO3(+) compared to those for SrNO3(+), consistent with more charge transfer between water molecules and Pb(ii). These results demonstrate that the different electronic structure of these ions significantly influences how they are solvated.


Asunto(s)
Electrones , Plomo/química , Nitratos/química , Estroncio/química , Agua/química , Iones/química , Estructura Molecular , Método de Montecarlo , Teoría Cuántica , Espectrofotometría Infrarroja
8.
Phys Chem Chem Phys ; 17(45): 30642-7, 2015 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-26524433

RESUMEN

The formation of a salt bridge in deprotonated glycine dimer anions in a solvent-free environment is investigated using both infrared multiple photon dissociation spectroscopy between 600 and 1800 cm(-1) and theory. The zwitterionic and nonzwitterionic forms of glycine in this complex are computed to be nearly iso-energetic, yet predominantly the zwitterionic form is observed experimentally. The zwitterion stability is attributed to both the Coulombic attraction and the high stabilization from intramolecular hydrogen bonding that drives the energetic cost of proton transfer in a solvent free environment. These results show that there is a fine balance between the stabilities of these two forms of the anion. Elucidating the role of intrinsic factors, such as hydrogen bonding, can lead to a better understanding of the stabilities of salt bridges in the interiors of large proteins or at protein interfaces.

9.
J Phys Chem A ; 118(30): 5657-66, 2014 Jul 31.
Artículo en Inglés | MEDLINE | ID: mdl-24999751

RESUMEN

The structures of hydrated guanidinium, Gdm(+)(H2O)n, where n = 1-5, were investigated with infrared photodissociation spectroscopy and with theory. The spectral bands in the free O-H (∼3600-3800 cm(-1)) and free N-H (∼3500-3600 cm(-1)) regions indicate that, for n between 1 and 3, water molecules bind between the NH2 groups in the plane of the ion forming one hydrogen bond with each amino group. This hydration structure differs from Gdm(+) in solution, where molecular dynamics simulations suggest that water molecules form linear H-bonds with the amino groups, likely a result of additional water-water interactions in solution that compete with the water-guanidinium interactions. At n = 4, changes in the free O-H and bonded O-H (∼3000-3500 cm(-1)) regions indicate water-water H-bonding and thus the onset of a second hydration shell. An inner shell coordination number of n = 3 is remarkably small for a monovalent cation. For Gdm(+)(H2O)5, the additional water molecule forms hydrogen bonds to other water molecules and not to the ion. These results indicate that Gdm(+) is weakly hydrated, and interactions with water molecules occur in the plane of the ion. This study offers the first experimental assignment of structures for small hydrates of Gdm(+), which provide insights into the unusual physicochemical properties of this ion.


Asunto(s)
Guanidina/química , Agua/química , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Isomerismo , Modelos Químicos , Soluciones , Espectrofotometría Infrarroja
10.
Water Resour Res ; 50(11): 9031-9047, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26612962

RESUMEN

Mixing models have become increasingly common tools for apportioning fluvial sediment load to various sediment sources across catchments using a wide variety of Bayesian and frequentist modeling approaches. In this study, we demonstrate how different model setups can impact upon resulting source apportionment estimates in a Bayesian framework via a one-factor-at-a-time (OFAT) sensitivity analysis. We formulate 13 versions of a mixing model, each with different error assumptions and model structural choices, and apply them to sediment geochemistry data from the River Blackwater, Norfolk, UK, to apportion suspended particulate matter (SPM) contributions from three sources (arable topsoils, road verges, and subsurface material) under base flow conditions between August 2012 and August 2013. Whilst all 13 models estimate subsurface sources to be the largest contributor of SPM (median ∼76%), comparison of apportionment estimates reveal varying degrees of sensitivity to changing priors, inclusion of covariance terms, incorporation of time-variant distributions, and methods of proportion characterization. We also demonstrate differences in apportionment results between a full and an empirical Bayesian setup, and between a Bayesian and a frequentist optimization approach. This OFAT sensitivity analysis reveals that mixing model structural choices and error assumptions can significantly impact upon sediment source apportionment results, with estimated median contributions in this study varying by up to 21% between model versions. Users of mixing models are therefore strongly advised to carefully consider and justify their choice of model structure prior to conducting sediment source apportionment investigations. KEY POINTS: An OFAT sensitivity analysis of sediment fingerprinting mixing models is conductedBayesian models display high sensitivity to error assumptions and structural choicesSource apportionment results differ between Bayesian and frequentist approaches.

11.
J Am Chem Soc ; 135(39): 14821-30, 2013 Oct 02.
Artículo en Inglés | MEDLINE | ID: mdl-24007314

RESUMEN

The structures and inherent stabilities of hydrated, protonated ammonia, select protonated primary, secondary, and tertiary amines as well as tetramethylammonium with 19-21 water molecules were investigated using infrared photodissociation (IRPD) spectroscopy and blackbody infrared radiative dissociation (BIRD) at 133 K. Magic number clusters (MNCs) with 20 water molecules were observed for all ions except tetramethylammonium, and the BIRD results indicate that these clusters have stable structures, which are relatively unaffected by addition of one water molecule but are disrupted in clusters with one less water molecule. IRPD spectra in the water free O-H stretch region are consistent with clathrate structures for the MNCs with 20 water molecules, whereas nonclathrate structures are indicated for tetramethylammonium as well as ions at the other cluster sizes. The locations of protonated ammonia and the protonated primary amines either in the interior or at the surface of a clathrate were determined by comparing IRPD spectra of these ions to those of reference ions; Rb(+) and protonated tert-butylammonia with 20 water molecules were used as references for an ion in the interior and at the surface of a clathrate, respectively. These results indicate that protonated ammonia is in the interior of the clathrate, whereas protonated methyl- and n-heptylamine are at the surface. Calculations suggest that the number of hydrogen bonds in these clusters does not directly correlate with structural stability, indicating that both the number and orientation of the hydrogen bonds are important. These experimental results should serve as benchmarks for computational studies aimed at elucidating ion effects on the hydrogen-bonding network of water molecules and the surface activity of ions.


Asunto(s)
Aminas/química , Amoníaco/química , Compuestos de Amonio Cuaternario/química , Modelos Moleculares , Protones , Espectrofotometría Infrarroja , Agua/química
12.
J Phys Chem A ; 117(30): 6571-9, 2013 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-23808387

RESUMEN

The origin of enhanced abundances for some hydrated alkali metal ions, M(+)(H2O)n, where M = Cs, Rb, K, Na, and Li with between 17 and 21 water molecules attached was investigated with infrared photodissociation (IRPD) spectroscopy and by blackbody infrared radiative dissociation (BIRD) at 133 K. The abundances of clusters of Cs(+), Rb(+), and K(+) with 18 and 20 water molecules are anomalously high compared to the corresponding clusters of Na(+), and Li(+) with 20 water molecules has only a slightly enhanced abundance. BIRD results indicate that the anomalous abundance at n = 20 for the larger ions is due to the high stability of this cluster, and the significant instability of the next largest cluster, consistent with a stable core structure with 20 water molecules. IRPD spectra in the free-OH region (∼3600-3800 cm(-1)) for Cs(+), Rb(+), and K(+) with 18 and 20 water molecules indicates that water molecules with a free-OH stretch accept two hydrogen bonds and donate one hydrogen bond (acceptor-acceptor-donor water) to other water molecules. No acceptor-donor (AD) bands are observed, consistent with clathrate structures for these ions. In contrast, the AD band is significant for Na(+), indicating that these clusters adopt different structures. Results for Li(+) indicate a contribution from clathrate structures at n = 20, but not at other cluster sizes. This analysis is supported by the relative intensities of bands in the hydrogen-bonding region for n = 20.

13.
J Subst Use ; 18(2): 82-107, 2013 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23525509

RESUMEN

BACKGROUND: The sale of over-the-counter (OTC) medicines from pharmacies can help individuals self-manage symptoms. However, some OTC medicines may be abused, with addiction and harms being increasingly recognised. This review describes the current knowledge and understanding of OTC medicine abuse. APPROACH: Comprehensive search of international empirical and review literature between 1990 and 2011. FINDINGS: OTC MEDICINE ABUSE WAS IDENTIFIED IN MANY COUNTRIES AND ALTHOUGH IMPLICATED PRODUCTS VARIED, FIVE KEY GROUPS EMERGED: codeine-based (especially compound analgesic) medicines, cough products (particularly dextromethorphan), sedative antihistamines, decongestants and laxatives. No clear patterns relating to those affected or their experiences were identified and they may represent a hard-to-reach group, which coupled with heterogeneous data, makes estimating the scale of abuse problematic. Associated harms included direct physiological or psychological harm (e.g. opiate addiction), harm from another ingredient (e.g. ibuprofen-related gastric bleeding) and associated social and economic problems. Strategies and interventions included limiting supplies, raising public and professional awareness and using existing services and Internet support groups, although associated evaluations were lacking. Terminological variations were identified. CONCLUSIONS: OTC medicine abuse is a recognised problem internationally but is currently incompletely understood. Research is needed to quantify scale of abuse, evaluate interventions and capture individual experiences, to inform policy, regulation and interventions.

14.
Sci Total Environ ; 869: 161837, 2023 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-36709887

RESUMEN

The EU Water Framework Directive (WFD) is widely regarded as a seminal piece of environmental legislation. However, two decades since its inception, many European waterbodies are failing to meet its ambitious goal to ensure 'good' quantitative and qualitative status. Here, we investigate the impact of the WFD upon the environmentally sensitive yet heavily impacted River Wensum, a lowland arable catchment in eastern England. Compiling a dataset of 10,950 water quality samples collected from 57 sites across the catchment at approximately monthly intervals during 2000-2022, we assess the spatio-temporal dynamics of 12 priority pollutants, identify the major drivers of water quality change, and evaluate current and future compliance with WFD goals. Our analysis reveals improvements in wastewater treatment initiated significant declines (11-50 %) in the concentration of key sewage pollution indicators (phosphorus, ammonium, biological oxygen demand (BOD)) during the early 2000s. Conversely, agricultural pollution indicators (nitrogen, suspended solids, pesticides) displayed either limited change or a deterioration in water quality, with oxidised nitrogen concentrations in particular having increased 23 % during 2015-2022. Concentration spikes of organic chemical contaminants in recent years (propyzamide, tetrachloroethylene) raise concerns about increased riverine pollution from hazardous substances. Similarly, changes in winter (+13 %) and summer (-7 %) discharge over the past two decades have increased the risk of diffuse pollution mobilisation and reduced the dilution of point source pollutants, respectively. By 2022, 'good' or 'high' water quality status for organic matter pollution indicators (dissolved oxygen, BOD, ammonium) was achieved for >98 % of samples, however WFD compliance fell to just 46 % for phosphorus and 1.8 % for nitrogen. Projections to the end of the third River Basin Management Plan cycle (2027) reveal that whilst phosphorus compliance is likely to improve, nitrogen compliance failure will persist due to the existence of catchment legacy stores and climate change induced impacts on nitrogen mobilisation.

15.
Sci Total Environ ; 804: 150146, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34509828

RESUMEN

Sewage effluent discharged from wastewater treatment plants (WWTPs) is a major driver of nitrogen (N) and phosphorus (P) enrichment, but tertiary treatment methods such as P-stripping have previously been shown to mitigate eutrophication risk. The aim of this study was to evaluate the impacts of sewage effluent discharged from WWTPs with contrasting classifications of tertiary treatment on nutrient dynamics across the River Wensum catchment, UK. River water samples were collected from 20 locations across the catchment at monthly intervals between October 2010 and September 2013, with 677 samples collected in total and analysed for a suite of hydrochemical parameters. The 20 sampling locations were divided into four classifications based on the type of upstream WWTP: (1) no WWTP; (2) WWTPs without P-stripping; (3) WWTPs with and without P-stripping; (4) WWTPs with P-stripping. Results revealed substantial overlaps in riverine nutrient composition making differentiation between classifications difficult. The majority of N (>97%) and P (~75%) was present in dissolved bioavailable forms across all sites and there was no significant difference in total N speciation between classifications. Total P (TP) speciation did, however, reveal higher proportions of particulate P at sites with no WWTP, indicating a greater P contribution of agricultural origin. Ratios of total dissolved to particulate P (TDP:TPP) and chloride concentrations proved effective discriminators of agricultural and sewage P, respectively, but phosphate­boron ratios (PO4:B) were ineffective discriminators in this catchment. Most importantly, there was no evidence that P-stripping reduced overall TP concentrations downstream of WWTPs, despite evidence of a per capita reduction, nor reduced the proportion of dissolved P released. These findings were attributed to P-stripping facilities serving larger populations and thus releasing greater effluent P load, thereby demonstrating that the presence of tertiary P-stripping alone is insufficient to overcome population pressures and ensure that rivers achieve good hydrochemical status.


Asunto(s)
Aguas del Alcantarillado , Contaminantes Químicos del Agua , Monitoreo del Ambiente , Nutrientes , Fósforo/análisis , Reino Unido , Contaminantes Químicos del Agua/análisis
16.
Sci Total Environ ; 817: 153000, 2022 Apr 15.
Artículo en Inglés | MEDLINE | ID: mdl-35031358

RESUMEN

The transfer of dissolved organic carbon (DOC) from land to watercourses plays a major role in the carbon cycle, and in the transport and fate of associated organic and inorganic contaminants. We investigated, at global scale, how the concentrations and properties of riverine DOC depend upon combinations of terrestrial source solutions. For topsoil, subsoil, groundwater and river solutions in different Köppen-Geiger climatic zones, we compiled published and new values of DOC concentration ([DOC]), radiocarbon signature (DO14C), and specific UV absorbance (SUVA). The average value of each DOC variable decreased significantly in magnitude from topsoil to subsoil to groundwater, permitting the terrestrial sources to be distinguished. We used the terrestrial data to simulate the riverine distributions of each variable, and also relationships between pairs of variables. To achieve good matches between observed and simulated data, it was necessary to optimise the distributions of water fractions contributed by each of the three terrestrial sources, and also to reduce the mean input terrestrial [DOC] values, to about 60% of the measured ones. One possible explanation for the required lowering of the modelled terrestrial [DOC] values might be unrepresentative sampling of terrestrial DOC, including dilution effects; another is the loss of DOC during riverine transport. High variations in simulated riverine DOC variables, which match observed data, are due predominantly to variations in source solution values, with a lesser contribution from the different combinations of source waters. On average, most DOC in rivers draining catchments with forest and/or grass-shrub land cover comes in similar amounts from topsoil and subsoil, with about 10% from groundwater. In rivers draining croplands, subsoil and groundwater solutions are the likely dominant DOC sources, while in wetland rivers most DOC is from topsoil.


Asunto(s)
Materia Orgánica Disuelta , Monitoreo del Ambiente , Carbono/análisis , Ciclo del Carbono , Ríos
17.
Clin Case Rep ; 9(7): e04370, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34257976

RESUMEN

Relationship-based medical care is essential in the management of chronic pain. Opioids are often ineffective and can cause significant harm. However, there is significant time pressure, and there are insufficient resources and guidelines for GPs to be able to offer alternatives, putting the NHS at risk of a growing opioid epidemic.

18.
ACS Macro Lett ; 10(5): 591-597, 2021 05 18.
Artículo en Inglés | MEDLINE | ID: mdl-35570773

RESUMEN

We report an approach to waterborne and degradable latex polymers. Emulsion polymerization of vinyl acetate (VA) with the cyclic ketene acetal 2-methylene-1,3-dioxepane (MDO) yields polymer particles and latex-based coatings that are hydrolytically degradable due to the presence of backbone ester groups. Polymerization under mildly basic conditions (pH 8) and at low temperature (40 °C) is critical: if the in-process pH is too acidic or the temperature too high, MDO is lost to hydrolysis, but when the media is too alkaline, VA monomer rapidly hydrolyzes. When coated onto commercial paper, films of these degradable particle dispersions show excellent oil and grease resistance as compared to non-degradable, VA-only compositions. This new class of latex is therefore well-suited for the design of next-generation, biodegradable and compostable single-use food service products, as well as for other applications where the erosion or degradation of polymer-based films and coatings is required.


Asunto(s)
Látex , Papel , Compuestos de Vinilo , Polimerizacion , Polímeros/química
19.
Pharmacy (Basel) ; 8(3)2020 Sep 02.
Artículo en Inglés | MEDLINE | ID: mdl-32887315

RESUMEN

Pharmacist prescribing is being increasingly undertaken to better use their skills and reduce the workload of existing prescribers such as doctors, often using formal processes to legitimate these activities. In developing countries like Saudi Arabia, however, pharmacists' prescribing remains informal with no legislation or formal training and there is a lack of research and understanding into such practices. Therefore, we aimed to describe current pharmacist prescribing practices in Saudi Arabia and explore pharmacists' views about pharmacists' prescribing. This is a cross-sectional survey study using an online questionnaire of hospital pharmacists in Saudi Arabia about pharmacists' prescribing, and associated views about prescribing legislation and barriers to implementing pharmacist prescribing. Over a quarter (28.5%) of pharmacists reported themselves as prescribers, 49% were following a collaborative prescribing model, 18% independent prescribing, and 33% were doing both. Ninety percent of prescribers reported confidence in prescribing the appropriate treatment and 92.3% perceived they will benefit from more prescribing training. Healthcare practice culture and pharmacist's competency were identified as barriers. There is an overall support for pharmacists' prescribing in Saudi Arabia among this sample of hospital pharmacists, with limitations in resources and the absence of standardized prescribing training being perceived as key barriers to pharmacists' prescribing.

20.
Sci Total Environ ; 724: 138253, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32247122

RESUMEN

In 2010, the UK government established the Demonstration Test Catchment (DTC) initiative to evaluate the extent to which on-farm mitigation measures can cost-effectively reduce the impacts of agricultural water pollution on river ecology whilst maintaining food production capacity. A central component of the DTC platform was the establishment of a comprehensive network of automated, web-based sensor technologies to generate high-temporal resolution (30 min) empirical datasets of surface water, groundwater and meteorological parameters over a long period (2011-2018). Utilising 8.9 million water quality measurements generated for the River Wensum, this paper demonstrates how long-term, high-resolution monitoring of hydrochemistry can improve our understanding of the complex temporal dynamics of riverine processes from 30 min to annual timescales. This paper explores the impact of groundwater-surface water interactions on instream pollutant concentrations (principally nitrogen, phosphorus and turbidity) and reveals how varying hydrochemical associations under contrasting flow regimes can elicit important information on the dominant pollution pathways. Furthermore, this paper examines the relationships between agricultural pollutants and precipitation events of varying magnitude, whilst demonstrating how high-resolution data can be utilised to develop conceptual models of hydrochemical processes for contrasting winter and summer seasons. Finally, this paper considers how high-resolution hydrochemical data can be used to increase land manager awareness of environmentally damaging farming operations and encourage the adoption of more water sensitive land management practices.

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