750 research outputs found
Determination of absorption length of CO2 and high power diode laser radiation for ordinary Portland cement
The laser beam absorption lengths of CO2 and a high power diode laser (HPDL) radiation for the ordinary Portland cement (OPC) surface of concrete have been determined. By employing Beer-Lambert’s law the absorption lengths for concrete of CO2 and a HPDL radiation were 470±22 μm and
177±15 μm respectively
Two Novels & Two Character Studies: Cassandra by Christa Wolf and Housekeeping by Marilynne Robinson
Senior Project submitted to The Division of Languages and Literature of Bard College
Assessing contaminated sediments in the context of multiple stressors
Sediments have a major role in ecosystem functioning but can also act as physical or chemical stressors. Anthropogenic activities may change the chemical constituency of sediments and the rate, frequency, and extent of sediment transport, deposition, and resuspension. The importance of sediments as stressors will depend on site ecosystem attributes and the magnitude and preponderance of co-occurring stressors. Contaminants are usually of greater ecological consequence in human-modified, depositional environments, where other anthropogenic stressors often co-occur. Risk assessments and restoration strategies should better consider the role of chemical contamination in the context of multiple stressors. There have been numerous advances in the temporal and spatial characterization of stressor exposures and quantification of biological responses. Contaminated sediments causing biological impairment tend to be patchy, whereas more pervasive anthropogenic stressors, such as alterations to habitat and flow, physical disturbance, and nutrient addition, may drive large-scale ecosystem responses. A systematic assessment of relevant ecosystem attributes and reference conditions can assist in understanding the importance of sediments in the context of other stressors. Experimental manipulations then allow for the controlled study of dominant stressors and the establishment of causal links. This approach will result in more effective management of watersheds and waterways. Environ. Toxicol. Chem. 2010;29:2625–2643. © 2010 SETACPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/78293/1/332_ftp.pd
Technology for Good: A systems exploration into the future of the digital platform economy
The digital platform economy has grown exponentially over the last two decades, resulting in a tech-enabled culture that is shaping a modern society. The system, framed in a North American context, is primarily driven by the commoditization of personal data. In this case, ‘big tech’ - companies like Facebook, Amazon, Apple, Microsoft, Netflix and Alphabet (Google) - profits off of data-driven insights that are used to create personalized services, targeted offers, suggested products and recommended search. Personal data gets treated like an asset to tech giants in particular. It cements the competitive advantage of those digital platforms that are able to exploit data-driven insights, enabling a recurring system of digital platforms trying to capture more and more personal information. It is not to say that digital platforms do not provide benefits to their users and society as a whole. Yet, the digital platform economy has perpetuated a complex relationship between benefiting from its users, and providing a set of (perceived) benefits back. In the current system, there is a lack of transparency in how the data exchange truly operates, prompting concern for whether the design of this system makes users vulnerable by default. This results in rising uncertainty around how the ecosystem should best interact with digital platforms in ways that concern data rights, data privacy and utilization of personal data. Through foresight and systems-thinking methodology, this project will seek to explore an alternative future that views data in a balanced, and optimistic, perspective. The report will begin by analyzing the past, in order to understand how we got to the present, which will help to imagine a desired future where tech is used for good
Healing maori through song and dance? Three case studies of recent New Zealand music theatre.
This thesis investigates the way "healing" may be seen to be represented and enacted by three recent New Zealand music theatre productions: Once Were Warriors, the Musical-Drama; The Whale Rider, On Stage; and Footprints/Tapuwae, a bicultural opera. This thesis addresses the ways each of these music theatre productions can be seen to dramatise ideologically informed notions of Maori cultural health through the encounter of Maori performance practices with American and European music theatre forms. Because the original colonial encounter between Maori and Pakeha was a wounding process, it may be possible that in order to construct a theatrical meeting between the "colonised" Maori and the "colonial" non-Maori, "healing" is an essential element by which to foster an idea of the post-colonial, bicultural togetherness of the nation. In all three productions, Maori song and dance forms are incorporated into a distinctive form of western music theatre: the American musical; the international spectacle; Wagnerian opera. Wagner's attempts to regenerate German culture through his music dramas can be compared to Maori renaissance idea(l)s of cultural "healing" through a "return" to Maori myths, traditions and song and dance
Bird species' tolerance to human pressures and associations with population change
Funding: E.M. and A.L. were funded by the Academy of Finland (projects 307909, 323527, and 329251). A.S. was supported through the framework of activities of the Spanish Government through the ‘Maria de Maeztu Centre of Excellence’ accreditation to IMEDEA (CSIC-UIB) (CEX2021-001198) and through the European Commission via the Horizon 2020 Marie Skłodowska-Curie Actions individual fellowships (grant no. 101027534).Aim Some species thrive in human-dominated environments, while others are highly sensitive to all human pressures. However, standardized estimates of species' tolerances to human pressures are lacking at large spatial extents and taxonomic breadth. Here, we quantify the world's bird species' tolerances to human pressures. The associated precision values can be applied to scientific research and conservation. Location Global. Time Period 2013–2021. Major Taxa Studied 6094 bird species. Methods We used binary observation data from eBird and modelled species' occurrences as a function of the Human Footprint Index (HFI). With these models, we predicted how likely each species was to occur under different levels of human pressures. Then, we calculated each species' Human Tolerance Index (HTI) as the level of the HFI where predicted occurrence probability was reduced to 50% of the maximum species' occurrence probability. We used resampling to obtain estimates of uncertainty of the Human Tolerance Indices. We also compared tolerances across species with increasing, stable, and decreasing population trends. Results We found that 22% of the bird species tolerated the most modified human-dominated environments, whereas 0.001% of species only occurred in the intact environments. We also found that HTI varied according to species' population trend categories, whereby species with decreasing population trends had a lower tolerance than species with increasing or stable population trends. Main Conclusions The estimated HTI indicates the potential of species to exist in a landscape of intensifying human pressures. It can identify species unable to tolerate these environments and inform subsequent conservation efforts. We found evidence that species' sensitivity to human-dominated environments may be driving birds' use of space. Bird species' tolerances are also linked to their population trends, making the tolerances a relevant addition to conservation planning.Peer reviewe
Pore-size and polymer affect the ability of filters for washing-machines to reduce domestic emissions of fibres to sewage
When clothes are worn and washed, they emit fibres into the ecosystem via discharges of sewage that have been linked to the global dispersion of clothing fibres. Facilities that treat sewage divert some fibres from sewage effluent to sludge, but no current methods of filtration eliminate their environmental release. While filters for washing-machines are sold to consumers with the argument they will reduce the emissions of fibres from clothes to the environment, there is insufficient scientific peer-reviewed evidence assessing their ability to retain fibres from washed clothes and reduce environmental contamination. To improve our understanding and develop more realistic methods to assess the efficiency of filters, we washed replicate cotton and polyester garments in replicate domestic front-loaded washing-machines with and without replicate filters (micro- and milli-meter-sized pores), and then quantified the masses of the fibres retained by the filters and those released in the effluent. Here we show micrometer-sized filters significantly reduced the mass of cotton by 67% (F-2,F-6= 11.69, P<0.01) compared to effluent from appliances with no filters, whilst filters in general reduced polyester fibres in their effluent by more than 65% (micrometer-sized pores) and 74% (millimeter-sized pores) compared to effluent from appliances with no filters (F-2,F-12= 5.20, P<0.05). While filters with micrometer-sized pores caught larger masses and total proportions of fibres than filters with millimeter-sized pores, the differences were only significant for the total proportions of cotton (t = 4.799 df = 4, P<0.01). For tests with garments of either types of polymer, the filtered effluent still contained up to a third of the original masses of fibres released from the garments. Given the diversity of clothes, polymers, appliances and filters currently sold to consumers, our work shows the value of increasing the rigour (e.g. more levels of replication) when testing filters and the need for further studies that test an even greater diversity of materials and methods in order to meet the growing demand for knowledge from governments, industry and the public
Uncertainty and decision making: Volcanic crisis scenarios
AbstractThe impact of uncertainty on Disaster Risk Reduction decision-making has become a pressing issue for debate over recent years. How do key officials interpret and accommodate uncertainty in science advice, forecasts and warnings into their decision making? Volcanic eruptions present a particularly uncertain hazard environment, and to accommodate this scientists utilize probabilistic techniques to inform decision-making. However, the interpretation of probabilities is influenced by their framing. We investigate how verbal or numerical probabilities affect decisions to evacuate a hypothetical town, and reasons given for that decision, based upon a volcanic eruption forecast. We find fewer evacuations for verbal terms than for equivalent numerical terms, and that the former is viewed as more ambiguous. This difference is greater for scientists, which we suggest is due to their greater familiarity with numerical probabilities and a belief that they are more certain. We also find that many participants have a poor understanding of the relationship between probability and time window stated, resulting in an incorrect assessment of overall likelihood and more evacuations for the lower likelihood version of two scenarios. Further, we find that career sector (scientist or non-scientist) influences evacuation decisions, with scientists tending to reduce the uncertainty by focusing on the quality and volume of information provided, while non-scientists tended to either acknowledge or suppress the uncertainty, focusing on actions to take. These findings demonstrate the importance of identifying communication strategies that mitigate different perceptions of forecasts, to both enhance end-user decision making and to prevent premature, delayed, or unnecessary actions
Communicating model uncertainty for natural hazards:A qualitative systematic thematic review
Natural hazard models are vital for all phases of risk assessment and disaster management. However, the high number of uncertainties inherent to these models is highly challenging for crisis communication. The non-communication of these is problematic as interdependencies between them, especially for multi-model approaches and cascading hazards, can result in much larger deep uncertainties. The recent upsurge in research into uncertainty communication makes it important to identify key lessons, areas for future development, and areas for future research. We present a systematic thematic literature review to identify methods for effective communication of model uncertainty. Themes identified include a) the need for clear uncertainty typologies, b) the need for effective engagement with users to identify which uncertainties to focus on, c) managing ensembles, confidence, bias, consensus and dissensus, d) methods for communicating specific uncertainties (e.g., maps, graphs, and time), and e) the lack of evaluation of many approaches currently in use. Finally, we identify lessons and areas for future investigation, and propose a framework to manage the communication of model related uncertainty with decision-makers, by integrating typology components that help identify and prioritise uncertainties. We conclude that scientists must first understand decision-maker needs, and then concentrate efforts on evaluating and communicating the decision-relevant uncertainties. Developing a shared uncertainty management scheme with users facilitates the management of different epistemological perspectives, accommodates the different values that underpin model assumptions and the judgements they prompt, and increases uncertainty tolerance. This is vital, as uncertainties will only increase as our model (and event) complexities increase.</p
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