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Background Bacterial respiratory coinfection in the setting of SARS-CoV-2 infection remains poorly described. A description of coinfection and antimicrobial usage is needed to guide ongoing antimicrobial stewardship. Objectives To assess the rate of empirical antimicrobial treatment in COVID-19 cases, assess the rate and methods of microbiological sampling, assess the rate of bacterial respiratory coinfections and evaluate the factors associated with antimicrobial therapy in this cohort. Methods Inpatients with positive SARS-CoV-2 PCR were recruited. Antibiotic prescription, choice and duration were recorded. Taking of microbiological samples (sputum culture, blood culture, urinary antigens) and culture positivity rate was also recorded. Linear regression was performed to determine factors associated with prolonged antimicrobial administration. Results A total of 117 patients were recruited; 84 (72%) were prescribed antimicrobial therapy for lower respiratory tract infections. Respiratory pathogens were identified in seven (6%) patients. The median duration of antimicrobial therapy was 7 days. C-reactive protein level, oxygen requirement and positive cultures were associated with prolonged duration of therapy. Conclusions The rate of bacterial coinfection in SARS-CoV-2 is low. Despite this, prolonged courses of antimicrobial therapy were prescribed in our cohort. We recommend active antimicrobial stewardship in COVID-19 cases to ensure appropriate antimicrobial prescribing.

Aims To assess clinical outcomes and adverse drug events in patients hospitalised with COVID-19 treated with off-label hydroxychloroquine (HCQ) and azithromycin (Az). Methods We performed a retrospective analysis of hospitalised patients who had a positive polymerase chain reaction test for SARS-CoV-2 and received HCQ plus Az or no targeted therapy. The primary end point was clinical improvement on day 7 defined as either hospital discharge or an improvement of 2 points on a 6-category ordinal scale. Secondary outcomes included mortality at day 28, intensive care admission, requirement for mechanical ventilation and incidence of adverse events. Results Data from a total of 134 patients were evaluated; 82 patients received HCQ/Az and 52 patients received no targeted therapy. Clinical improvement was seen in 26.8% of patients who received HCQ/Az but this was not significant. The rates of intensive care transfer and mechanical ventilation were higher in the treatment group, but these differences were not significant. Mortality at day 28 was significantly higher in the treatment group (P = .03). Hypoglycaemia elevated liver function tests and QT prolongation were monitored in both groups. The risk of QT prolongation was significantly higher in the treatment group. Treatment was stopped early in 6 (7.3%) patients due to adverse events. Conclusion Although patients who received HCQ/Az were more severely ill the administration of these repurposed drugs did not result in clinical improvement and was associated with a significant increase in toxicity. This descriptive study highlights the importance of monitoring all repurposed agents for adverse events.

River infrastructure is one of the primary threats to riverine ecosystems globally, altering hydromorphological processes and isolating habitats. Instream barriers and low-head dams can have significant effects on system connectivity, but despite this, very few empirical studies have assessed the impacts of these structures on suspended sediment transport. Through a paired turbidity study over a 20-month monitoring period we investigated the differences in suspended sediment flux above and below two low-head dams in the south-east of Ireland. Using sediment balance as a proxy for sediment storage, results showed that a net-export of sediment from the study reach occurred for 68% of the high-flow events analysed. As the primary controls on sediment dynamics at the downstream reach depend on sediment availability from upstream, we argue that these results indicate the presence of a substantial local source of sediment between monitoring stations that cannot be explained by natural intra-reach erosional processes. Here we hypothesise that as sediment supply from the catchment becomes exhausted, the structure's impounded zone (typically considered a depositional area) provides a major sediment source to the downstream reach. Our rationale is that if sediment trapped behind the weir is periodically available for transportation at the rates and frequencies observed in this study, then we can infer that both structures must be trapping sediment under lower flows.

Aim To assess clinical outcomes and adverse drug events in patients hospitalised with COVID -19 treated with off- label hydroxychloroquine and azithromycin. Methods We performed a retrospective analysis of hospitalised COVID-19+ patients who received hydroxychloroquine plus azithromycin over a 2 week period. The primary end point was clinical improvement on day 7 defined as either hospital discharge or an improvement of two points on a six-category ordinal scale. Secondary outcomes evaluated included mortality at day 28, ICU admission, requirement for mechanical ventilation and incidence of adverse drug events. Results Data from a total of 82 patients with laboratory confirmed SARS-CoV-2 infection was evaluated. Clinical improvement was seen in 26.8% of patients at Day 7. 31% of patients were admitted to ICU, 16 (19.5%) underwent mechanical ventilation and Day 28 mortality was 28%. Age over 70, history of cardiovascular disease and 3 or more comorbidities were risk factors for mortality. The incidence of adverse drug events was 42%. No patient experienced a Grade 4 or 5 toxicity. Over a fifth of patients (23) had raised LFTs (65% had raised LFTs at baseline), 11 patients experienced prolonged QT and 1 patient experienced grade 1 hypoglycaemia. Treatment was stopped early in 6(7.3%) patients due to prolonged QT interval or LFT elevations. Conclusion This descriptive study details the clinical outcomes of COVID-19 positive patients treated with these agents and highlights the importance of monitoring all repurposed agents for adverse drug events.

Fluvial riparian vegetation (RV) links fluvial and terrestrial ecosystems. It is under significant pressure from anthropogenic activities, and, therefore, the management and restoration of RV are increasingly important worldwide. RV has been investigated from different perspectives, so knowledge on its structure and function is widely distributed. An important step forward is to convert existing knowledge into an overview easily accessible—for example, for use in decision-making and management. We aim to provide an overview of ecosystem services provided by RV by adopting a structured approach to identify the ecosystem services, describe their characteristics, and rank the importance of each service. We evaluate each service within four main riparian vegetation types adopting a global perspective to derive a broad concept. Subsequently, we introduce a guided framework for use in RV management based on our structured approach. We also identify knowledge gaps and evaluate the opportunities an ecosystem service approach offers to RV management.

This research investigates organizational change in six Canadian universities framed as “prioritization,” which is a ranking method using predefined metrics for the comprehensive review and evaluation of academic and administrative programs. Our research found the following: (a) no prioritization process reached the implementation stage; (b) financial performance was not significantly impacted; (c) differences in pace, sequencing, and linearity had little to no impact on the outcomes; (d) the process of prioritization itself introduced political hardship to university leadership, including broad mistrust. Our analysis shows that prioritization initiatives have not provided a directly attributable impact on the outcomes at each of the universities. In short, there was much ado about nothing. Implications for universities will be discussed.

Sediment connectivity, though typically viewed as subsidiary to concerns surrounding fish passage, serves an important role in a functioning riverine ecosystem, with both substrate stability and particle size distribution acting as key determinants of benthic community structure and spawning habitat. However, despite more than a decade of pressure to restore stream continuity under the Water Framework Directive (WFD), there have been very few empirical studies on the impact that low-head dams (i.e. weirs) have on bed and suspended sediment conveyance, and little progress in the development of replicable quantitative methodologies for doing so. In this study we explore these knowledge gaps through field investigations of three gravel-cobble streams in southeast Ireland using RFID technology to investigate bedload connectivity, and integrated high-resolution monitoring of turbidity and discrete suspended sediment sampling to establish above dam vs, below dam patterns of suspended sediment conveyance.Suspended sediment inputs and outputs over a range of flow conditions (above baseflow) reveal elevated sediment flux at the downstream station (below dam) compared to that coming into the reach (above dam). These observations are indicative of a local source of sediment between monitor­ing stations. Here we suggest that as sediment inputs became exhausted before peak discharge, the structure’s impounded zone (typically considered a depositional area) becomes the dominant source of sediment to the downstream reach. We argue that if sediment trapped behind the structure is available for transportation during high flow events, the system must be trapping sediment under lower flows, which is consistent with field observations.Results for bedload connectivity and tracer transport over low-head dams demonstrate that particles exceeding the reach D90 can be carried through and over these structures, which is consistent with what has been reported from the US. This observation suggests that both structures may have reached a state of ‘transient storage’ as hypothesized by other authors. However, RFID tracer data when reinterpreted as fractional transport rates using a workflow based on existing empirical relations, indicate patterns consistent with supply-limited conditions downstream, demonstrating conflicting lines of evidence between the event-scale tracer movement and long-term sediment regime. Utilizing our empirical data and additional observations collected from a stationary RFID antenna mounted on a weir crest, we expand on existing models and mechanisms to show how a system may continue to exhibit supply-limited conditions downstream without the need for a net attenuation of sediment to occur indefinitely.These results indicate that low-head dams may continue to alter the hydrosedimentary processes of fluvial systems long after dam construction and any hypothetical storage capacity has been reached. Though the impact low-head dams have on sediment disconnectivity to the downstream reach is likely to be variable and relatively localized, we hypothesize that the magnitude of any supply-limitation experienced downstream is predominantly a function of both dam height and the structure’s propensity to become drowned out under high flows.

Many aquatic species of conservation concern exist at low densities and are inherently difficult to detect or monitor using conventional methods. However, the introduction of environmental (e)DNA has recently transformed our ability to detect these species and enables effective deployment of limited conservation resources. Identifying areas for breeding, as well as the ecological distribution of species, is vital to the survival or recovery of a conservation species (i.e., areas of critical habitat). In many species, spawning events are associated with a higher relative abundance of DNA released within an aquatic system (i.e., gametes, skin cells etc.), making this the ideal time to monitor these species using eDNA techniques. This study aims to examine whether a “snapshot” eDNA sampling approach (i.e., samples taken at fixed points in chronological time) could reveal areas of critical habitat including spawning sites for our target species Petromyzon marinus. We utilized a species‐specific qPCR assay to monitor spatial and temporal patterns in eDNA concentration within two river catchments in Ireland over three consecutive years. We found that eDNA concentration increased at the onset of observed spawning activity and patterns of concentration increased from downstream to upstream over time, suggesting dispersal into the higher reaches as the spawning season progressed. We found P. marinus to be present upstream of several potential barriers to migration, sometimes in significant numbers. Our results also show that the addition of a lamprey‐specific fish pass at an “impassable” weir, although assisting in ascent, did not have any significant impact on eDNA concentration upstream after the pass had been installed. eDNA concentration was also found to be significantly correlated with both the number of fish and the number of nests encountered. The application of snapshot sampling techniques for species monitoring therefore has substantial potential for the management of low‐density species in fast‐moving aquatic systems. Irish Research Council Inland Fisheries Ireland

Multiple stressors affect stream ecosystems worldwide and their interactions are of particular concern, with gaps existing in understanding stressor impacts on stream communities. Addressing these knowledge gaps will aid in targeting and designing of appropriate mitigation measures. In this study, the agricultural stressors fine sediment (ambient, low, medium, high), phosphorus (ambient, enriched) and nitrogen (ambient, enriched) were manipulated simultaneously in 64 streamside mesocosms to determine their individual and combined effects on the macroinvertebrate community (benthos and drift). Stressor levels were chosen to reflect those typically observed in European agricultural streams. A 21-day colonisation period was followed by a 14-day manipulative period. Results indicate that added sediment had the most pervasive effects, significantly reducing total macroinvertebrate abundance, total EPT abundance and abundances of three common EPT taxa. The greatest effect was at high sediment cover (90%), with decreasing negative impacts at medium (50%) and low (30%) covers. Added sediment also led to higher drift propensities for nine of the twelve drift variables. The effects of nitrogen and phosphorus were relatively weak compared to sediment. Several complex and unpredictable 2-way or 3-way interactions among stressors were observed. While sediment addition generally reduced total abundance at high levels, this decrease was amplified by P enrichment at low sediment, whereas the opposite effect occurred at medium sediment and little effect at high sediment. These results have direct implications for water management as they highlight the importance of managing sediment inputs while also considering the complex interactions which can occur between sediment and nutrient stressors.

Background Mental health disorders have a negative impact on the individual, society and global economy. The prevalence of mental disorders is increasing in young people, if unaddressed, they may develop into severe and chronic illnesses. Despite this, research into youth mental health recovery is limited. The current study aims to develop a theoretical framework of recovery in youth mental health and identify what facilitates this process. Methods Fourteen parents of children engaged with the Child and Adolescent Mental Health Service were interviewed in relation to their understanding of youth mental health recovery. The transcripts of these interviews were analysed using the constructivist grounded theory approach. Results A theoretical model of youth mental health was developed. The model provides an understanding of (a) the characteristics of youth mental health recovery, (b) the facilitators of recovery and (c) the barriers to recovery. The theory suggests that due to developmental factors youth mental health recovery occurs within the ecological context of complex social systems. Conclusions The theory reflects elements of existing developmental and recovery research and provides a novel understanding of youth mental health recovery. This model may inform social, government and service attitudes and policy, and highlights areas for future research.

This study evaluates two desk‐based approaches for building an inventory of man‐made river obstacles. The creation of a river obstacle inventory is a vital first step in developing a prioritization process for obstacle removal and/or modification. In this study, a desktop geographical information system analysis of two rivers and their tributary network was undertaken, using two different approaches. The first involved analysing historical maps, satellite imagery, and Ordnance Survey Ireland Discovery Series maps and producing a geo‐referenced layer of all the potential river obstacles. The second involved developing a geo‐referenced layer of potential river obstacles based on the intersections between elements of the transport network (roads and railways) and river systems. To determine the effectiveness of the desk studies, the located obstacles were cross‐referenced with actual obstacles verified through a field survey. The desk studies identified several thousand potential obstacles. The study utilizing a range of maps consistently located a greater number of actual obstacles than the desk study based on intersections between the transport and river networks. The results indicate that desk‐based research offers an efficient and effective method for locating river obstacles and can guide subsequent field surveys aimed at confirming the presence of obstacles. This is particularly useful for eliminating from study large stretches of rivers that would otherwise need to be walked to confirm the presence, or otherwise, of potential river obstacles. In this regard, desk‐based exercises can offer opportunities to save on both time and cost in larger river assessments.

The Atlantic salmon (Salmo salar L.) has worldwide ecological, cultural and economic importance. The species has undergone extensive decline across its native range, yet concerns have been raised about its invasive potential in the Pacific. Knowledge on the distribution of this species is vital for addressing conservation goals.This study presents an eDNA assay to detect S. salar in water samples, using quantitative PCR (qPCR) technology. Species-specific primers and a minor groove binding (MGB) probe were designed for the assay, based on the mitochondrial cytochrome oxidase I (COI) gene.The results of this study indicate that eDNA is a highly sensitive tool for detecting S. salar in situ, and could potentially provide an alternative, non-invasive method for determining the distribution of this species.

The impact of fine sediments on both habitat quality and macroinvertebrate communities of riverine systems has been well documented over recent years. However, there is a paucity of studies examining the mechanisms that relate macroinvertebrate sensitivity and responses of individual macroinvertebrate species to burial by sediment. Laboratory-based burial experiments were undertaken to study the response of some EPT species including Baetis rhodani, Ecdyonurus insignis, Rhithrogena semicolorata, Hydropsyche siltalai, Rhyacophila dorsalis and the amphipod Gammarus duebeni to burial. A range of burial conditions were studied which included five sediment fractions at two burial depths. Responses were variable across species and, overall, the ranking of the determinants that impacted on species responses to burial was burial depth > sediment class > species source, with no detectable effect linked to body size. Increased burial depth had the most marked effects on emergence times, while slower escape times were also observed from the finer sediment classes. Species source also influenced responses with some upland species taking longer or failing to emerge from burial. Further mechanistic studies, based on EPT species, are required to enhance our understanding of how and at what level sediment affect species, an essential step in developing pressure-specific biological metrics.

This chapter involves a discussion of a case study to explore teachers' beliefs on the nature of reality (ontology) and knowledge (epistemology) within an International Baccalaureate Middle Years Program at the International School of Amsterdam. The study is positioned within the constructivist-interpretive paradigm and allows for the emergence of a holistic and contextualized understanding of teachers' beliefs and practices. The chapter includes reflection on the author's ontology and epistemology and its impact on the research undertaking. The study is an attempt to understand whether teachers' beliefs impact their approaches to teaching within this inquiry-based environment. Comprehensive teacher profiles were generated for three participants, all experienced teachers, who teach Science, English Literature, and Spanish. The findings indicate that the participants' approaches to teaching resonate strongly with their ontological and epistemological beliefs. The chapter also includes consideration of the role that scholarship played in the generation of the teacher profiles.

The aim of this chapter is to highlight how diet and nutrition factors can add to the psychological formulation process by complementing traditional models of constructing formulation. It explores how this information may be effectively captured during regular therapeutic dialogue and used to directly impact on both well-being and distress. Furthermore, it illustrates how what we eat affects how we think and feel every day of our lives, and thus should represent a fundamental component of a comprehensive approach to mental health care. The chapter encloses sample open-ended questions relating to diet and nutrition to be considered for use in a clinical interview and points to the validity of current measures available to practitioners. The chapter also explores what instruments would be best used to stimulate a necessary discussion with the client around diet and nutrition. The chapter proposes that the process of formulation should be all-encompassing and incorporate, where possible, all relevant variables of influence across individual, interpersonal, biological, social and cultural domains.

open access article; International audience; [u]Background & Aims[/u] Malnutrition in older adults results in significant personal, social, and economic burden. To combat this complex, multifactorial issue, evidence-based knowledge is needed on the modifiable determinants of malnutrition. Systematic reviews of prospective studies are lacking in this area; therefore, the aim of this systematic review was to investigate the modifiable determinants of malnutrition in older adults. [u]Methods[/u] A systematic approach was taken to conduct this review. Eight databases were searched. Prospective cohort studies with participants of a mean age of 65 years or over were included. Studies were required to measure at least one determinant at baseline and malnutrition as outcome at follow-up. Study quality was assessed using a modified version of the Quality in Prognosis Studies (QUIPS) tool. Pooling of data in a meta-analysis was not possible therefore the findings of each study were synthesized narratively. A descriptive synthesis of studies was used to present results due the heterogeneity of population source and setting, definitions of determinants and outcomes. Consistency of findings was assessed using the schema: strong evidence, moderate evidence, low evidence, and conflicting evidence. [u]Results[/u] Twenty-three studies were included in the final review. Thirty potentially modifiable determinants across seven domains (oral, psychosocial, medication and care, health, physical function, lifestyle, eating) were included. The majority of studies had a high risk of bias and were of a low quality. There is moderate evidence that hospitalisation, eating dependency, poor self-perceived health, poor physical function and poor appetite are determinants of malnutrition. Moderate evidence suggests that chewing difficulties, mouth pain, gum issues co-morbidity, visual and hearing impairments, smoking status, alcohol consumption and physical activity levels, complaints about taste of food and specific nutrient intake are not determinants of malnutrition. There is low evidence that loss of interest in life, access to meals and wheels, and modified texture diets are determinants of malnutrition. Furthermore, there is low evidence that psychological distress, anxiety, loneliness, access to transport and wellbeing, hunger and thirst are not determinants of malnutrition. There appears to be conflicting evidence that dental status, swallowing, cognitive function, depression, residential status, medication intake and/or polypharmacy, constipation, periodontal disease are determinants of malnutrition. [u]Conclusion[/u] There are multiple potentially modifiable determinants of malnutrition however strong robust evidence is lacking for the majority of determinants. Better prospective cohort studies are required. With an increasingly aging population, targeting modifiable factors will be crucial to the effective treatment and prevention of malnutrition.

This paper presents an empirical study that uses the movement of RFID tracers to investigate the impacts of low-head dams on solid transport dynamics in coarse-bedded streams. Here we report on the influence of two structures located in Ireland's South-East, both of which indicate that particles greater than the reach D90 can be carried through and over low-head dams. This observation suggests that both structures may have reached a state of ‘transient storage’ as hypothesized by previous research. However, when the data were reinterpreted as fractional transport rates using a novel application of existing empirical relations, we observed patterns consistent with supply-limited conditions downstream. Expanding on existing conceptual models and mechanisms, we illustrate how a system may continue to exhibit supply-limited conditions downstream without the need for a net attenuation of sediment to occur indefinitely. We propose that once a transient storage capacity has been reached, the system then enters a state of dynamic disconnectivity where the long-term average sediment flux equals that under reference conditions, but now with the amplitude and wavelength of these sediment fluctuations having increased. We hypothesize that the time-lag associated with the reduced frequency of events competent enough to move bedload over the structure accounts for the time necessary to complete the ‘fill’ phase of the transient storage dynamic; a process that will continue until both the fill and flow thresholds are again met to allow the system to reenter the ‘scour’ phase. This model reconciles how a system may exhibit a sediment deficit for time intervals longer than those experienced under reference conditions. As water and sediment are the drivers of channel morphology and associated habitat units, the impact a structure has on a channel's sediment regime should therefore form part of any assessment regarding the prioritization of barriers for removal or remediation.

Objectives: Physeal-sparing techniques for anterior cruciate ligament (ACL) reconstruction have previously been described as safe treatment for adolescent ACL tears in patients with open physes, however few studies to date have reported on return-to-sport or patient reported outcome scores for this specific patient population. This study examined patient reported outcomes in children who underwent a physeal-sparing ACL reconstruction with a minimum of two-year follow-up. Methods: Surgical logs of ACLR performed at a single pediatric/adolescent sports medicine center from 2011 to 2016 were reviewed. Patients with open physes who had ACLR with a hybrid physeal sparing or all-epiphyseal technique were identified. Patients were treated by one of two pediatric sports trained orthopedic surgeons. Their demographics, operative reports, rehabilitative course, time to return-to-play, and post-operative course were retrospectively reviewed. Prospective patient reported outcomes scores, ACL-Return to Sport after Injury (ACL-RSI) and International Knee Documentation Committee (IKDC) or Pediatric IKDC (Pedi-IKDC) and return to sport questionnaire including pre-injury primary sport and competition level, ability to return to pre-injury level of competition following ACLR and subsequent ACL injury were collected. Results: There were 49 patients who met inclusion criteria. Prospectively collected data was obtained for 25 patients at an average of 4.6 (range 2.1-8.0) years following surgery. The average chronological age of patients at time of surgery was 12.8 ± 1.4 years with an average bone age of 13.5 ± 1.3 years. At mid-term follow-up, the average chronological age was 17.2 ± 2.0 years. Average Pedi-IKDC or IKDC score was 94.2 ± 9.2 and ACL-RSI Score was 89.2 ± 18.3. There were 23 patients who considered themselves athletes prior to surgery, 8 patients identifying as recreational athletes competing in town or school leagues and 15 patients identifying as competitive athletes participating on youth travel or club leagues. All patients reported the ability to return to their primary sport following ACLR, with 74% returning to the same or higher level of competition, of which 6 were recreational athletes and 11 were competitive athletes. In addition, 6 patients did not complete outcomes data, but had suffered tear of their ipsilateral (3) or contralateral (3) side and were treated at the same facility. These patients were included in calculation of overall re-tear rate of 12.5% (5 patients) and contralateral tear of 25% (8 patients). Conclusion: Mid-term results of patients treated with a hybrid physeal-sparing or all-epiphyseal ACLR were favorable, with adolescents reporting a high level of functional ability and strong psychological readiness to engage in athletic activities. Re-tear and contralateral tear rates were equivalent to other reported studies. These physeal-sparing techniques demonstrate the ability for young athletes to successfully remain physically active and involved in their sports several years following surgery.

In May 2018, an outbreak of gastrointestinal illnesses due to norovirus occurred at Camp Arifjan, Kuwait. The outbreak lasted 14 days, and a total of 91 cases, of which 8 were laboratory confirmed and 83 were suspected, were identified. Because the cases occurred among a population of several thousand service members transiting through a crowded, congregate setting of open bays of up to 250 beds, shared bathrooms and showers, and large dining facilities, the risk of hundreds or thousands of cases was significant. The responsible preventive medicine authorities promptly recognized the potential threat and organized and monitored the comprehensive response that limited the spread of the illness and the duration of the outbreak. This report summarizes findings of the field investigation and the preventive medicine response conducted from 18 May-3 June 2018 at Camp Arifjan.

Knowledge of the location, physical attributes and impacts of obstacles on river connectivity is a requirement for any mitigating action aimed at restoring the connectivity of a river system. Here, we present a study that recorded the numbers and physical diversity of obstacles in 10 river catchments in Ireland, together with the impact these structures had on overall river connectivity. A total of 372 obstacles were recorded, 3 of these were dams, and the remainder were low-head weirs/sluices, obstacles associated with road or rail crossings of rivers and natural structures. The degree of fragmentation was estimated in each catchment by calculating obstacle density and the Dendritic Connectivity Index (DCI). DCI scores were calculated for 4 native Irish fish species with different life-histories, namely diadromous (Atlantic salmon, sea trout, European eel, sea lamprey) and potamodromous (brown trout). Obstacle density ranged between 1.2 and 0.02 obstacles/km of river. Six of the 10 catchments had at least one obstacle located on the mainstem river at least 5 km from its mouth/confluence. These 6 catchments typically had the lowest connectivity scores for diadromous species and ranged between 0.6 and 44.1 (a fully connected river would receive a maximum score of 100). While there was no significant correlation between obstacle density and the DCI score for diadromous fish, a significant negative correlation was detected between obstacle density and the DCI score for potamodromous brown trout. Here, we highlight the merit of these obstacle assessments and associated challenges for decision-making relating to prioritisation of obstacles for removal or modification.

The degradation of freshwater resources and loss of freshwater biodiversity by anthropogenic activities, including agriculture, are of major global concern. Together with diffuse pollutants, point sources, such as where cattle have direct access to riparian margins and watercourses, can potentially present significant environmental challenges. These can include impacts on stream morphology, increased sedimentation, nutrient additions, microbial contamination, and impacts on aquatic biota. Mitigation measures aimed at reducing these frequently include reducing the amount of time cattle spend in riparian margins and watercourses. This is often accomplished through the provision of an alternative water supply and grazing management, or even cattle exclusion measures. Although a number of studies refer to potential negative impacts, there has been little attempt to review previous research on this topic. The key aim of this paper is to collate and review these disparate studies, as well as those relating to the effectiveness of mitigation measures. Although it is difficult to draw generalizations from studies due to the inherent variability between and within catchments, evidence pertaining to impacts in relation to sedimentation, pathogens, and riparian margin vegetation were strong. Conclusions in relation to impacts on stream morphology and nutrient parameters were less clear, whereas studies on responses of macroinvertebrate communities were particularly variable, with differences due to cattle access difficult to separate from catchment scale effects. A greater understanding of the impact of cattle access on watercourses under varying conditions will help inform policymakers on the cost effectiveness of existing management criteria and will help in revising existing measures.

peer-reviewed Freshwaters worldwide are affected by multiple stressors. Timing of inputs and pathways of delivery can influence the impact stressors have on freshwater communities. In particular, effects of point versus diffuse nutrient inputs on stream macroinvertebrates are poorly understood. Point-source inputs tend to pose a chronic problem, whereas diffuse inputs tend to be acute with short concentration spikes. We manipulated three key agricultural stressors, phosphorus (ambient, chronic, acute), nitrogen (ambient, chronic, acute) and fine sediment (ambient, high), in 112 stream mesocosms (26 days colonisation, 18 days of manipulations) and determined the individual and combined effects of these stressors on stream macroinvertebrate communities (benthos and drift). Chronic nutrient treatments continuously received high concentrations of P and/or N. Acute channels received the same continuous enrichment, but concentrations were doubled during two 3-hour periods (day 6, day 13) to simulate acute nutrient inputs during rainstorms. Sediment was the most pervasive stressor in the benthos, reducing total macroinvertebrate abundance and richness, EPT (mayflies, stoneflies, caddisflies) abundance and richness. By contrast, N or P enrichment did not affect any of the six studied community-level metrics. In the drift assemblage, enrichment effects became more prevalent the longer the experiment went on. Sediment was the dominant driver of drift responses at the beginning of the experiment. After the first acute nutrient pulse, sediment remained the most influential stressor but its effects started to fade. After the second pulse, N became the dominant stressor. In general, impacts of either N or P on the drift were due to chronic exposure, with acute nutrient pulses having no additional effects. Overall, our findings imply that cost-effective management should focus on mitigating sediment inputs first and tackle chronic nutrient inputs second. Freshwater managers should also take into account the length of exposure to high nutrient concentrations, rather than merely the concentrations themselves.

The concentrations of toxic and potentially toxic elements (As, V, Cr, Fe, Co, Ni, Cu, B, Ba, Sr, Zn, Mn, Pb and Cd) collected from benthic sediments in the water bodies of the city of Addis Ababa were investigated to evaluate their distribution and pollution levels. The average concentration of Cr, Mn, Pb, Ni, Fe, Cu, Zn and Cd exceeded the threshold effect level of the sediment quality guidelines. Many of the concentrations were higher than previously reported. The sediments were moderately to heavily polluted with Cr, non-polluted to severe with Cu, Zn and Pb elements, moderate to heavily polluted with Ni and non-polluted by As and Cd. The sediments were enriched with these elements in the increasing order As

A wide range of methods are commonly used to measure deposited fine sediment and quantify substrate quality in rivers as part of bioassessment or monitoring programmes. In this laboratory-based experiment known amounts of three sediment types (sand, topsoil, peat) were added to mesocosms and four methods of measuring deposited fine sediment; turbidity, estimation of released sediment, Turner–Hillis deposited sediment sampler (DSS) and visual estimation of % surface cover were evaluated. The objective of the study was to evaluate which of these methods for estimating deposited sediment best discriminates between levels of deposited fine sediment added and assesses the effects of inter-observer variability between % surface cover estimations. While turbidity measurement and the resuspension method were strongly related to levels of added sediment, it proved difficult using the two methods to resolve differences between adjacent levels of added sediment e.g. 50 g and 100 g. Surface cover estimations were also strongly related to added sediment levels and were better able to distinguish between adjacent levels of added sediment. Furthermore, we found no significant differences between the % surface cover estimations between observers. Results from this laboratory experiment strongly endorse the use of visual estimation of surface cover in field studies. Further work evaluating the turbidity and re-suspension methods under field conditions would also be beneficial.