Diffusive equilibrium in thin films provides evidence of suppression of hyporheic exchange and large-scale nitrate transformation in a groundwater-fed river

The hyporheic zone of riverbed sediments has the potential to attenuate nitrate from upwelling, polluted groundwater. However, the coarse-scale (5–10 cm) measurement of nitrogen biogeochemistry in the hyporheic zone can often mask fine-scale (<1 cm) biogeochemical patterns, especially in near-surface sediments, leading to incomplete or inaccurate representation of the capacity of the hyporheic zone to transform upwelling NO3−. In this study, we utilised diffusive equilibrium in thin-films samplers to capture high resolution (cm-scale) vertical concentration profiles of NO3−, SO42−, Fe and Mn in the upper 15 cm of armoured and permeable riverbed sediments. The goal was to test whether nitrate attenuation was occurring in a sub-reach characterised by strong vertical (upwelling) water fluxes. The vertical concentration profiles obtained from diffusive equilibrium in thin-films samplers indicate considerable cm-scale variability in NO3− (4.4 ± 2.9 mg N/L), SO42− (9.9 ± 3.1 mg/l) and dissolved Fe (1.6 ± 2.1 mg/l) and Mn (0.2 ± 0.2 mg/l). However, the overall trend suggests the absence of substantial net chemical transformations and surface-subsurface water mixing in the shallow sediments of our sub-reach under baseflow conditions. The significance of this is that upwelling NO3−-rich groundwater does not appear to be attenuated in the riverbed sediments at <15 cm depth as might occur where hyporheic exchange flows deliver organic matter to the sediments for metabolic processes. It would appear that the chemical patterns observed in the shallow sediments of our sub-reach are not controlled exclusively by redox processes and/or hyporheic exchange flows. Deeper-seated groundwater fluxes and hydro-stratigraphy may be additional important drivers of chemical patterns in the shallow sediments of our study sub-reach. Copyright © 2014 John Wiley & Sons, Ltd

Interpreting spatial patterns in redox and coupled water-nitrogen fluxes in the streambed of a gaining river reach

Water pathways through permeable riverbeds are multi-dimensional, including lateral hyporheic exchange flows as well as vertical (upwelling and downwelling) fluxes. The influence of different pathways of water on solute patterns and the supply of nitrate and other redox-sensitive chemical species in the riverbed is poorly understood but could be environmentally significant. For example, nitrate-rich upwelling water in the gaining reaches of groundwater-fed rivers has the potential to supply significant quantities of nitrate through the riverbed to surface waters, constraining opportunities to deliver the goals of the EU Water Framework Directive to achieve ‘good ecological status’. We show that patterns in porewater chemistry in the armoured river bed of a gaining reach (River Leith, Cumbria) reflect the spatial variability in different sources of water; oxic conditions being associated with preferential discharge from groundwater and reducing conditions with longitudinal and lateral fluxes of water due to water movement from riparian zones and/or hyporheic exchange flows. Our findings demonstrate the important control of both vertical and lateral water fluxes on patterns of redox-sensitive chemical species in the river bed. Furthermore, under stable, baseflow conditions (<Q90) a zone of preferential discharge, comprising 20 % of the reach by area contributes 4–9 % of the total nitrate being transported through the reach in surface water, highlighting the need to understand the spatial distribution of such preferential discharge locations at the catchment scale to establish their importance for nitrate delivery to the stream channel

Diffusive equilibrium in thin-films (DET) provides evidence of suppression of hyporheic exchange and large-scale nitrate transformation in a groundwater-fed river

The hyporheic zone of riverbed sediments has the potential to attenuate nitrate from upwelling, polluted groundwater. However, the coarse-scale (5 – 10 cm) measurement of nitrogen biogeochemistry in the hyporheic zone can often mask fine-scale (<1 cm) biogeochemical patterns, especially in near-surface sediments, leading to incomplete or inaccurate representation of the capacity of the hyporheic zone to transform upwelling NO3-. In this study, we utilised diffusive equilibrium in thin-films (DET) samplers to capture high resolution (cm-scale) vertical concentration profiles of NO3-, SO42-, Fe and Mn in the upper 15 cm of armoured and permeable riverbed sediments. The goal was to test whether nitrate attenuation was occurring in a sub-reach characterised by strong vertical (upwelling) water fluxes. The vertical concentration profiles obtained from DET samplers indicate considerable cm-scale variability in NO3- (4.4 ± 2.9 mg N/L), SO42- (9.9 ± 3.1 mg/L) and dissolved Fe (1.6 ± 2.1 mg/L) and Mn (0.2 ± 0.2 mg/L). However, the overall trend suggests the absence of substantial net chemical transformations and surface-subsurface water mixing in the shallow sediments of our sub-reach under baseflow conditions. The significance of this is that upwelling NO3--rich groundwater does not appear to be attenuated in the riverbed sediments at <15 cm depth as might occur where hyporheic exchange flows deliver organic matter to the sediments for metabolic processes. It would appear that the chemical patterns observed in the shallow sediments of our sub-reach are not controlled exclusively by redox processes and / or hyporheic exchange flows. Deeper-seated groundwater fluxes and hydro-stratigraphy may be additional important drivers of chemical patterns in the shallow sediments of our study sub-reach. This article is protected by copyright. All rights reserved

Auto-driven Photo Elicitation Interviews in Research with Children: Ethical and Practical Considerations

Children can sometimes find it difficult to articulate their experiences if they have to rely solely on words. Giving children the opportunity to use arts-based research approaches can support their participation in research and create a bridge that enables them to express their perspectives and feelings. This paper focuses on the ethical and practical considerations when using photo elicitation interviews (PEI) in research with children. The discussion and examples provided are drawn from an international study that used auto-driven PEI, where photographs are taken by children themselves, to explore children’s experiences of living with a chronic condition and the impact condition management may have on their everyday lives. In this paper we critically explore the issues arising from our use of PEI including children’s participation and engagement, balancing power and control, and keeping children safe. The main areas of focus for the paper are how PEI provided a means of shifting control; how setting photographic boundaries influenced our PEI study with children; and how we addressed risks associated with the method. Our experience shows that PEI is an engaging and valuable research method, providing a powerful medium for obtaining rich data with children. However, PEI is challenging and it requires researchers to conscientiously address ethical and practical aspects that extend beyond those inherent to standard (words-alone) interviews

Love, rights and solidarity: studying children's participation using Honneth's theory of recognition

Recent attempts to theorize children’s participation have drawn on a wide range of ideas, concepts and models from political and social theory. The aim of this article is to explore the specific usefulness of Honneth’s theory of a ‘struggle for recognition’ in thinking about this area of practice. The article identifies what is distinctive about Honneth’s theory of recognition, and how it differs from other theories of recognition. It then considers the relevance of Honneth’s conceptual framework to the social position of children, including those who may be involved in a variety of ‘participatory’ activities. It looks at how useful Honneth’s ideas are in direct engagement with young people’s praxis, drawing on ethnographic research with members of a children and young people’s forum. The article concludes by reflecting on the implications of this theoretical approach and the further questions which it opens up for theories of participation and of adult–child relations more generally

Effectiveness of Metyrapone in Treating Cushing's Syndrome: A Retrospective Multicenter Study in 195 Patients

Background: Cushing's syndrome (CS) is a severe condition with excess mortality and significant morbidity necessitating control of hypercortisolemia. There are few data documenting use of the steroidogenesis inhibitor metyrapone for this purpose. Objective: The objective was to assess the effectiveness of metyrapone in controlling cortisol excess in a contemporary series of patients with CS. Design: This was designed as a retrospective, multicenter study. Setting: Thirteen University hospitals were studied. Patients: We studied a total of 195 patients with proven CS: 115 Cushing's disease, 37 ectopic ACTH syndrome, 43 ACTH-independent disease (adrenocortical carcinoma 10, adrenal adenoma 30, and ACTH-independent adrenal hyperplasia 3). Measurements: Measurements included biochemical parameters of activity of CS: mean serum cortisol “day-curve” (CDC) (target 150–300 nmol/L); 9 am serum cortisol; 24-hour urinary free cortisol (UFC). Results: A total of 164/195 received metyrapone monotherapy. Mean age was 49.6 ± 15.7 years; mean duration of therapy 8 months (median 3 mo, range 3 d to 11.6 y). There were significant improvements on metyrapone, first evaluation to last review: CDC (91 patients, 722.9 nmol/L [26.2 μg/dL] vs 348.6 nmol/L [12.6 μg/dL]; P < .0001); 9 am cortisol (123 patients, 882.9 nmol/L [32.0 μg/dL] vs 491.1 nmol/L [17.8 μg/dL]; P < .0001); and UFC (37 patients, 1483 nmol/24 h [537 μg/24 h] vs 452.6 nmol/24 h [164 μg/24 h]; P = .003). Overall, control at last review: 55%, 43%, 46%, and 76% of patients who had CDCs, UFCs, 9 am cortisol less than 331 nmol/L (12.0 μg/dL), and 9 am cortisol less than upper limit of normal/600 nmol/L (21.7 μg/dL). Median final dose: Cushing's disease 1375 mg; ectopic ACTH syndrome 1500 mg; benign adrenal disease 750 mg; and adrenocortical carcinoma 1250 mg. Adverse events occurred in 25% of patients, mostly mild gastrointestinal upset and dizziness, usually within 2 weeks of initiation or dose increase, all reversible. Conclusions: Metyrapone is effective therapy for short- and long-term control of hypercortisolemia in CS

Tamoxifen for prevention of breast cancer: extended long-term follow-up of the IBIS-I breast cancer prevention trial

© Cuzick et al. Open Access article distributed under the terms of CC BY.http://dx.doi.org/10.1016/S1470-2045(14)71171-

Enhanced hyporheic exchange flow around woody debris does not increase nitrate reduction in a sandy streambed

Anthropogenic nitrogen pollution is a critical problem in freshwaters. Although riverbeds are known to attenuate nitrate, it is not known if large woody debris (LWD) can increase this ecosystem service through enhanced hyporheic exchange and streambed residence time. Over a year, we monitored the surface water and pore water chemistry at 200 points along a ~50m reach of a lowland sandy stream with three natural LWD structures. We directly injected 15N-nitrate at 108 locations within the top 1.5m of the streambed to quantify in situ denitrification, anammox and dissimilatory nitrate reduction to ammonia, which, on average, contributed 85%, 10% and 5% of total nitrate reduction, respectively. Total nitrate reducing activity ranged from 0-16µM h-1 and was highest in the top 30cm of the stream bed. Depth, ambient nitrate and water residence time explained 44% of the observed variation in nitrate reduction; fastest rates were associated with slow flow and shallow depths. In autumn, when the river was in spate, nitrate reduction (in situ and laboratory measures) was enhanced around the LWD compared with non-woody areas, but this was not seen in the spring and summer. Overall, there was no significant effect of LWD on nitrate reduction rates in surrounding streambed sediments, but higher pore water nitrate concentrations and shorter residence times, close to LWD, indicated enhanced delivery of surface water into the streambed under high flow. When hyporheic exchange is too strong, overall nitrate reduction is inhibited due to short flow-paths and associated high oxygen concentrations

Childhood Labor in India: issues and complexities

It is estimated that more than 12 million children in India under the age of 14 engage in paid labor at least part time, due mostly to economic reasons. Dominant discourses about childhood however conceptualize childhood labor not only as unethical but as exploitation. This article explored will the tensions between Western notions of childhood (within which paid labor is considered taboo) and the realities of children's lives in India, arguing that childhood labor must be contextualized and understood not only as a colonial legacy but also as part of its socio-cultural context. The author argues that separating children from the world of work fosters a culture of childhood that emphasizes entitlement over participation and privileges the rights of the consumer over children's rights as citizens