707 research outputs found

    Autonomous sensors for nutrient monitoring

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    Cultural eutrophication is the process whereby a body of water becomes over-enriched with nutrients, in particular nitrogen (N) and phosphorus (P), resulting in algal blooms and subsequent death and decomposition which deplete oxygen levels in the water (i.e. hypoxia), leading to the loss of aquatic animals (e.g. fishes). This is caused by excess N and P. Agriculture is the major source to Irish rivers and estuaries, with 70% of P loads and 82% of N loads attributed to agricultural sources . Hypoxia in the Gulf of Mexico has been linked to excessive N loading. Nuisance algal blooms in Lake Erie have been linked to agricultural P. Previous efforts have concentrated on measuring agricultural runoff directly using grab samples or spot measurements, but high frequency sampling will be essential to accurately characterize the extent and temporal resolution of agricultural impacts. Low cost real-time nutrient sensors are critical for quantifying the influence of agriculture on freshwater, and more broadly, for effective water management throughout Irish, European, and American river basins

    An optical colour sensor to monitor the marine environment

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    This research aims to develop a flexible, simple, low-cost, robust, deployable sensor with anti- fouling measures to detect colour change in marine environments. Such a sensor could be used to detect events, inform sampling regimes in coastal areas and act as a qualitative decision support tool. This is useful to decision makers in cities, coastal areas and globally and as gathering data can be expensive using commercial instruments a low cost sensor enables more data to be collected with a better spatial range and resolution. Detecting colour change in water could give warning of events like green tides, e.g. (right) in QuingDao, China, often caused by cyanobacteria

    Demonstrating the performance of a real-time optical colorimetric sensing device for monitoring the marine environment

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    The research objective is to develop a cost-effective event detection sensing system to inform targeted sampling by traditional means and act as a decision support tool. The Optical Colorimetric Sensor (OCS) uses an array of LEDs to detect change in water coloration and alert to events. A prototype comprises the following features: an LED array light source, photodiode detectors, robust deployable design, GSM communication and antifouling measures. The system has been evaluated using laboratory and field measurements. The system is robust and deployable in the aquatic environment. The OCS shows potential to detect events in the environment due to a pollution

    Development of a real-time, continuous, optical turbidity and colorimetric sensing device for the marine environment

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    Our aquatic heritage is a vital resource. Anthropogenic activities and industrialisation, however, have led to increased pressures on our natural waters, and consequently, careful management is required to ensure their sustainability and health for future generations. It is important to acknowledge that one can only manage what one can measure, and therefore, environmental sensing of riverine, estuarine and marine waters is becoming increasingly important to ensure that European directives such as the Water Framework Directive [1], the Bathing Water Directive [2] and the Marine Strategy Framework Directive [3] can be met. Traditional approaches have typically involved the intermittent collection of samples at the relevant monitoring location (grab sampling), the transportation of the samples to the laboratory, the analysis of samples using various lab-based analytical techniques and the evaluation of results. In relation to aquatic environmental monitoring, this approach is not always ideal due a number of factors, for example, (1) the possibility of missing events due to insufficient sampling frequencies, (2) the potential for sample contamination from the point of collection to the laboratory, and (3) the inherent lead time from sample collection to analytical results can be problematic with regards to delayed reaction protocols and cause traceability. This research seeks to resolve some of these outstanding issues through the development of a prototype, real-time, continuous turbidity and colorimetric sensing device for the marine environment. The new device seeks to improve upon our existing Multi-Channel Optical Device (MOD) [4], see Figure 1, in terms of robustness and data transmittance capabilities. Potential applications are the detection of harmful algal bloom (HABs), for example cyanobacteria, which are toxic to both humans and animal species. The sensing device uses an array of coloured LEDs to not only detect and quantify changes in turbidity but also to signal changes in colour intensity. Significant challenges exist to ensure the robustness of sensing systems in the aforementioned aquatic environments, and these issues vary in significance depending on the classification and remoteness of the monitoring location. Of these challenges, biofouling is one of the key limiting factors. One important aspect of this research is that it also incorporates the testing and assessment of recently developed biofouling mitigation techniques. This device is based on a generic platform, which will potentially result in a plug and play approach for various other sensor elements. Figure 1: Multi-Channel Optical device (MOD). Acknowledgements: This research is funded by a Beaufort Marine Research Award, which is carried out under the Sea Change Strategy and the Strategy for Science Technology and Innovation (2006-2013), with the support of the Marine Institute, funded under the Marine Research Sub-Programme of the National Development Plan 2007–2013. [1] EU website, Water Framework Directive, [on-line], http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2000:327:0001:0072:EN:PDF, Accessed 2012(November). [2] EU Website, Bathing Water Directive, [on-line], http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2006:064:0037:0051:EN:PDF, Accessed 2012(November). [3] EU Website, Marine Strategy Framework Directive, [on-line], http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2008:164:0019:0040:EN:PDF, Accessed 2012(November). [4] Lau, K. T., Kim, J., O’Sullivan, T. et al, "Sensing technologies for monitoring the marine environment", MARTECH Conference, Cadiz, Spain, (2011)

    Monitoring the marine environment using a low-cost colorimetric optical sensor

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    Anthropogenic activities have led to increased stress on our marine and other aquatic environments. There is a pressing need to monitor, measure, understand and mitigate the causes of these pressures. This paper presents the development and preliminary testing of a low-cost colorimetric optical sensor to detect colour-linked events in the marine environment. Potential applications may include the detection of Harmful Algal Blooms (HAB), which due to the production of toxins have deleterious effects on marine ecosystems and can ultimately lead to human, fish, bird and mammal deaths. Preliminary results indicate the capability of the sensor to differentiate between the colour signatures of several environmental samples

    Biodiversity 2020: climate change evaluation report

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    In 2011, the government published Biodiversity 2020: A strategy for England’s wildlife and ecosystem services [1]. This strategy for England builds on the 2011 Natural Environment White Paper - NEWP [2] and provides a comprehensive picture of how we are implementing our international and EU commitments. It sets out the strategic direction for biodiversity policy between 2011-2020 on land (including rivers and lakes) and at sea, and forms part of the UK’s commitments under the ‘the Aichi targets’ agreed in 2010 under the United Nations Convention of Biological Diversity’s Strategic Plan for Biodiversity 2011-2020 [3]. Defra is committed to evaluating the Biodiversity 2020 strategy and has a public commitment to assess climate change adaptation measures. This document sets out the information on assessing how action under Biodiversity 2020 has helped our wildlife and ecosystems to adapt to climate change. Biodiversity 2020 aims to halt the loss of biodiversity and restore functioning ecosystems for wildlife and for people. The outcomes and actions in Biodiversity 2020, although wider in scope, aimed to increase resilience of our wildlife and ecosystems in the face of a changing climate. In order to inform the assessment, we have defined which of the measurable outputs under Biodiversity 2020 contribute to resilience. Biodiversity 2020 included plans to develop and publish a dedicated set of indicators to assess progress towards the delivery of the strategy. The latest list (at the time of writing), published in 2017, contains 24 biodiversity indicators [4] that would help inform progress towards achieving specific outcomes, they are also highly relevant to the outputs (detailed below) that form the basis for this evaluation. The Adaptation Sub-Committee’s 2017 UK Climate Change Risk Assessment Evidence Report [5] sets out the priority climate change risks and opportunities for the UK. The ASC also produced a review of progress in the National Adaptation Programme - “Progress in preparing for climate change” [6], which highlights adaptation priorities and progress being made towards achieving them. The UK Government’s response to the ASC [7] review includes a set of recommendations, of which Recommendation 6 states that “Action should be taken to enhance the condition of priority habitats and the abundance and range of priority species”. The recommendation further iterated that “This action should maintain or extend the level of ambition that was included in Biodiversity 2020” and that “An evaluation should be undertaken of Biodiversity 2020 including the extent to which goals have been met and of the implications for resilience to climate change.” To this, end an evaluation process has been put in place to define: a. What worked and why? Which actions or activities have had the greatest benefit in terms of delivering the desired outcomes? And, conversely, what prevented progress? b. Where are the opportunities? What are the financial, political, scientific and social opportunities for furthering the desired outcomes in the future? These objectives underpin the evaluation process for actions to date, and will also inform future actions and the iteration of a new nature strategy for England

    Genome sequencing of the extinct Eurasian wild aurochs, Bos primigenius, illuminates the phylogeography and evolution of cattle

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    Background Domestication of the now-extinct wild aurochs, Bos primigenius, gave rise to the two major domestic extant cattle taxa, B. taurus and B. indicus. While previous genetic studies have shed some light on the evolutionary relationships between European aurochs and modern cattle, important questions remain unanswered, including the phylogenetic status of aurochs, whether gene flow from aurochs into early domestic populations occurred, and which genomic regions were subject to selection processes during and after domestication. Here, we address these questions using whole-genome sequencing data generated from an approximately 6,750-year-old British aurochs bone and genome sequence data from 81 additional cattle plus genome-wide single nucleotide polymorphism data from a diverse panel of 1,225 modern animals. Results Phylogenomic analyses place the aurochs as a distinct outgroup to the domestic B. taurus lineage, supporting the predominant Near Eastern origin of European cattle. Conversely, traditional British and Irish breeds share more genetic variants with this aurochs specimen than other European populations, supporting localized gene flow from aurochs into the ancestors of modern British and Irish cattle, perhaps through purposeful restocking by early herders in Britain. Finally, the functions of genes showing evidence for positive selection in B. taurus are enriched for neurobiology, growth, metabolism and immunobiology, suggesting that these biological processes have been important in the domestication of cattle. Conclusions This work provides important new information regarding the origins and functional evolution of modern cattle, revealing that the interface between early European domestic populations and wild aurochs was significantly more complex than previously thought

    The state of the Martian climate

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    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

    The X-ray properties of million solar mass black holes

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    We present new Chandra X-ray observations of seven low-mass black holes (~1e6 Msun) accreting at low Eddington ratios between -2.0<log L/Ledd<-1.5. We compare the X-ray properties of these seven low-mass active galactic nuclei (AGN) to a total of 73 other low-mass AGN in the literature with published Chandra observations (with Eddington ratios extending from -2.0<log L/Ledd<-0.1). We do not find any statistical differences between low- and high-Eddington ratio low-mass AGN in the distributions of their X-ray to ultraviolet luminosity ratios (aox), or in their X-ray spectral shapes. Furthermore, the aox distribution of low-L/Ledd AGN displays an X-ray weak tail that is also observed within high-L/Ledd objects. Our results indicate that between -2<log L/Ledd<-0.1, there is no systematic change in the structure of the accretion flow for active galaxies hosting 1e6 Msun black holes. We examine the accuracy of current bolometric luminosity estimates for our low-L/Ledd objects with new Chandra observations, and it is plausible that their Eddington ratios could be underestimated by up to an order of magnitude. If so, then in analogy with weak emission line quasars, we suggest that accretion from a geometrically thick, radiatively inefficient `slim disk' could explain their diverse properties in aox. Alternatively, if current Eddington ratios are in fact correct (or overestimated), then the X-ray weak tail would imply that there is diversity in disk/corona couplings among individual low-mass objects. Finally, we conclude by noting that the aox distribution for low-mass black holes may have favorable consequences for the epoch of cosmic reionization being driven by AGN.Comment: 14 pages, 6 figures, 6 tables. Accepted for publication in Ap
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