238 research outputs found
Common carp (Cyprinus carpio L.) alters its feeding niche in response to changing food resources: direct observations in simulated ponds
We used customized fish tanks as model fish ponds to observe grazing, swimming, and conspecific social behavior of common carp (Cyprinus carpio) under variable food-resource conditions to assess alterations in feeding niche. Different food and feeding situations were created by using only pond water or pond water plus pond bottom sediment or pond water plus pond bottom sediment and artificial feeding. All tanks were fertilized twice, prior to stocking and 2 weeks later after starting the experiment to stimulate natural food production. Common carp preferred artificial feed over benthic macroinvertebrates, followed by zooplankton. Common carp did not prefer any group of phytoplankton in any treatment. Common carp was mainly benthic in habitat choice, feeding on benthic macroinvertebrates when only plankton and benthic macroinvertebrates were available in the system. In the absence of benthic macroinvertebrates, their feeding niche shifted from near the bottom of the tanks to the water column where they spent 85% of the total time and fed principally on zooplankton. Common carp readily switched to artificial feed when available, which led to better growth. Common carp preferred to graze individually. Behavioral observations of common carp in tanks yielded new information that assists our understanding of their ecological niche. This knowledge could be potentially used to further the development of common carp aquaculture
Erratum : Levelized cost of CO2 mitigation from hydrogen production routes (Energy Environ. Sci. (2019) 12 (19–40) DOI: 10.1039/C8EE02079E)
Some of the references had missing or incorrect details; corrected sections of the affected text are provided below. The reference list has also been corrected and is reproduced in full at the end of this correction. In Section 3.1, ‘‘For literature studies including natural gas supply chain contributions to GHG emissions, the reported total range of LCE values are 10.72–15.86 kg CO2e kg-1 H2 (average of 12.4 of kg CO2e kg-1 H2) 26–34 without CCS and 3.1–5.9 kg CO2e kg-1 H2 (average of 4.3 kg CO2e kg-1 H2) with CCS at 90% capture.27,28,32,33,35’’ should read as ‘‘For literature studies including natural gas supply chain contributions to GHG emissions, the reported total range of LCE values are 10.72–15.86 kg CO2e kg-1 H2 (average of 12.4 of kg CO2e kg-1 H2) 30–38 without CCS and 3.1–5.9 kg CO2e kg-1 H2 (average of 4.3 kg CO2e kg-1 H2) with CCS at 90% capture.31,32,36,37,39’’ ‘‘Direct GHG emissions from the SMR hydrogen production phase are approximately 8–10 t CO2e t-1 H2, 60% of which is generated from the process chemistry, while the remaining 40% arises from heat and power sources required.36’’ should read as ‘‘Direct GHG emissions from the SMR hydrogen production phase are approximately 8–10 t CO2e t-1 H2, 60% of which is generated from the process chemistry, while the remaining 40% arises from heat and power sources required.26’’ ‘‘The majority of CO2 produced exits in two streams, a diluted stream (stack gases with CO2 concentration 5–10 vol%) and a concentrated stream (approximately 50% by vol after pressure swing adsorption).37’’ should read as ‘‘The majority of CO2 produced exits in two streams, a diluted stream (stack gases with CO2 concentration 5–10 vol%) and a concentrated stream (approximately 50% by vol after pressure swing adsorption).27’’ ‘‘If deep decarbonisation is required and emissions must be further reduced from the entire process, then an amine solvent (MEA) based CCS process might be used to capture up to 90% of the CO2 contained in the stack gases,38 although demonstrated removal rates are typically 80%.39’’ should read as ‘‘If deep decarbonisation is required and emissions must be further reduced from the entire process, then an amine solvent (MEA) based CCS process might be used to capture up to 90% of the CO2 contained in the stack gases,28 although demonstrated removal rates are typically 80%.2
Levelized cost of CO2 mitigation from hydrogen production routes
Different technologies produce hydrogen with varying cost and carbon footprints over the entire resource supply chain and manufacturing steps. This paper examines the relative costs of carbon mitigation from a life cycle perspective for 12 different hydrogen production techniques using fossil fuels, nuclear energy and renewable sources by technology substitution. Production costs and life cycle emissions are parameterized and re-estimated from currently available assessments to produce robust ranges to describe uncertainties for each technology. Hydrogen production routes are then compared using a combination of metrics, levelized cost of carbon mitigation and the proportional decarbonization benchmarked against steam methane reforming, to provide a clearer picture of the relative merits of various hydrogen production pathways, the limitations of technologies and the research challenges that need to be addressed for cost-effective decarbonization pathways. The results show that there is a trade-off between the cost of mitigation and the proportion of decarbonization achieved. The most cost-effective methods of decarbonization still utilize fossil feedstocks due to their low cost of extraction and processing, but only offer moderate decarbonisation levels due to previous underestimations of supply chain emissions contributions. Methane pyrolysis may be the most cost-effective short-term abatement solution, but its emissions reduction performance is heavily dependent on managing supply chain emissions whilst cost effectiveness is governed by the price of solid carbon. Renewable electrolytic routes offer significantly higher emissions reductions, but production routes are more complex than those that utilise naturally-occurring energy-dense fuels and hydrogen costs are high at modest renewable energy capacity factors. Nuclear routes are highly cost-effective mitigation options, but could suffer from regionally varied perceptions of safety and concerns regarding proliferation and the available data lacks depth and transparency. Better-performing fossil-based hydrogen production technologies with lower decarbonization fractions will be required to minimise the total cost of decarbonization but may not be commensurate with ambitious climate targets
Levelized cost of CO2 mitigation from hydrogen production routes
Different technologies produce hydrogen with varying cost and carbon footprints over the entire resource supply chain and manufacturing steps. This paper examines the relative costs of carbon mitigation from a life cycle perspective for 12 different hydrogen production techniques using fossil fuels, nuclear energy and renewable sources by technology substitution. Production costs and life cycle emissions are parameterized and re-estimated from currently available assessments to produce robust ranges to describe uncertainties for each technology. Hydrogen production routes are then compared using a combination of metrics, levelized cost of carbon mitigation and the proportional decarbonization benchmarked against steam methane reforming, to provide a clearer picture of the relative merits of various hydrogen production pathways, the limitations of technologies and the research challenges that need to be addressed for cost-effective decarbonization pathways. The results show that there is a trade-off between the cost of mitigation and the proportion of decarbonization achieved. The most cost-effective methods of decarbonization still utilize fossil feedstocks due to their low cost of extraction and processing, but only offer moderate decarbonisation levels due to previous underestimations of supply chain emissions contributions. Methane pyrolysis may be the most cost-effective short-term abatement solution, but its emissions reduction performance is heavily dependent on managing supply chain emissions whilst cost effectiveness is governed by the price of solid carbon. Renewable electrolytic routes offer significantly higher emissions reductions, but production routes are more complex than those that utilise naturally-occurring energy-dense fuels and hydrogen costs are high at modest renewable energy capacity factors. Nuclear routes are highly cost-effective mitigation options, but could suffer from regionally varied perceptions of safety and concerns regarding proliferation and the available data lacks depth and transparency. Better-performing fossil-based hydrogen production technologies with lower decarbonization fractions will be required to minimise the total cost of decarbonization but may not be commensurate with ambitious climate targets
Ethical and Scientific Considerations Regarding Animal Testing and Research
In 1959, William Russell and Rex Burch published the seminal book, The Principles of Humane Experimental Technique, which emphasized reduction, refinement, and replacement of animal use, principles which have since been referred to as the ‘‘3 Rs’’. These principles encouraged researchers to work to reduce the number of animals used in experiments to the minimum considered necessary, refine or limit the pain and distress to which animals are exposed, and replace the use of animals with non-animal alternatives when possible. Despite the attention brought to this issue by Russell and Burch and since, the number of animals used in research and testing has continued to increase, raising serious ethical and scientific issues. Further, while the ‘‘3 Rs’’ capture crucially important concepts, they do not adequately reflect the substantial developments in our new knowledge about the cognitive and emotional capabilities of animals, the individual interests of animals, or an updated understanding of potential harms associated with animal research. This Overview provides a brief summary of the ethical and scientific considerations regarding the use of animals in research and testing, and accompanies a Collection entitled Animals, Research, and Alternatives: Measuring Progress 50 Years Later, which aims to spur ethical and scientific advancement
Improving the practicality of using non-aversive handling methods to reduce background stress and anxiety in laboratory mice
Handling can stimulate stress and anxiety in laboratory animals that negatively impacts welfare
and introduces a confounding factor in many areas of research. Picking up mice by the tail is a major
source of handling stress that results in strong aversion to the handler, while mice familiarised with
being picked up in a tunnel or cupped on the open hand show low stress and anxiety, and actively seek
interaction with their handlers. Here we investigate the duration and frequency of handling required for
effective familiarisation with these non-aversive handling methods, and test whether this is sufficient
to prevent aversion and anxiety when animals then experience immobilisation and a mild procedure
(subcutaneous injection). Very brief handling (2 s) was sufficient to familiarise mice with tunnel
handling, even when experienced only during cage cleaning. Brief but more frequent handling was
needed for familiarisation with cup handling, while pick up by tail induced strong aversion even when
handling was brief and infrequent. Experience of repeated immobilisation and subcutaneous injection
did not reverse the positive effects of tunnel handling. Our findings demonstrate that replacing tail with
tunnel handling during routine cage cleaning and procedures provides a major refinement with little if
any cost for familiarisation
Captivating behaviour: mouse models, experimental genetics and reductionist returns in the neurosciences
This a post-print, author-produced version of an article accepted for publication in The Sociological Review. Copyright © 2010 Wiley Blackwell. The definitive version is available at www3.interscience.wiley.comNo Abstract availabl
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Pollinator monitoring more than pays for itself
1. Resilient pollination services depend on sufficient abundance of pollinating insects over time. Currently, however, most knowledge about the status and trends of pollinators is based on changes in pollinator species richness and distribution only. 2. Systematic, long‐term monitoring of pollinators is urgently needed to provide baseline information on their status, to identify the drivers of declines and to inform suitable response measures. 3. Power analysis was used to determine the number of sites required to detect a 30% change in pollinator populations over 10 years. We then evaluated the full economic costs of implementing four national monitoring schemes in the UK: (a) professional pollinator monitoring, (b) professional pollination service monitoring, (c) volunteer collected pan traps and (d) volunteer focal floral observations. These costs were compared to (a) the costs of implementing separate, expert‐designed research and monitoring networks and (b) the economic benefits of pollination services threatened by pollinator loss. 4. Estimated scheme costs ranged from £6,159/year for a 75‐site volunteer focal flower observation scheme to £2.7 M/year for an 800‐site professional pollination service monitoring network. The estimated research costs saved using the site network as research infrastructure range from £1.46–4.17 M/year. The economic value of UK crop yield lost following a 30% decline in pollinators was estimated at ~£188 M/year. 5. Synthesis and applications. We evaluated the full costs of running pollinator monitoring schemes against the economic benefits to research and society they provide. The annual costs of monitoring are <0.02% of the economic value of pollination services that would be lost after a 30% decline in pollination services. Furthermore, by providing high‐quality scientific data, monitoring schemes would save at least £1.5 on data collection per £1 spent. Our findings demonstrate that long‐term systematic monitoring can be a cost‐effective tool for both answering key research questions and setting action points for policymakers. Careful consideration must be given to scheme design, the logistics of national‐scale implementation and resulting data quality when selecting the most appropriate combination of surveyors, methods and site networks to deliver a successful scheme
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Costing conservation: an expert appraisal of the pollinator habitat benefits of England’s entry level stewardship
Pollination services provided by insects play a key role in English crop production and wider ecology. Despite growing evidence of the negative effects of habitat loss on pollinator populations, limited policy support is available to reverse this pressure. One measure that may provide beneficial habitat to pollinators is England’s entry level stewardship agri-environment scheme. This study uses a novel expert survey to develop weights for a range of models which adjust the balance of Entry Level Stewardship options within the current area of spending. The annual costs of establishing and maintaining these option compositions were estimated at £59.3–£12.4 M above current expenditure. Although this produced substantial reduction in private cost:benefit ratios, the benefits of the scheme to pollinator habitat rose by 7–140 %; significantly increasing the public cost:benefit ratio. This study demonstrates that the scheme has significant untapped potential to provide good quality habitat for pollinators across England, even within existing expenditure. The findings should open debate on the costs and benefits of specific entry level stewardship management options and how these can be enhanced to benefit both participants and biodiversity more equitably
Prosumers and smart grid technologies in Denmark: developing user competences in smart grid households
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