1,721,022 research outputs found
Response of electricity sector air pollution emissions to drought conditions in the western United States
No full textWater is needed for hydroelectric generation and to cool thermoelectric power plants. This dependence on water makes electricity generation vulnerable to droughts. Furthermore, because power sector CO2 emissions amount to approximately one third of total US emissions, droughts could influence the inter-annual variability of state- and national-scale emissions. However, the magnitude of drought-induced changes in power sector emissions is not well understood, especially in the context of climate mitigation policies. Using multivariate linear regressions, we find that droughts are positively correlated to increases in electricity generation from natural gas in California, Idaho, Oregon, and Washington; and from coal in Colorado, Montana, Oregon, Utah, Washington, and Wyoming. Using a statistical model, we estimate that this shift in generation sources led to total increases in regional emissions of 100 Mt of CO2, 45 kt of SO2, and 57 kt of NO x from 2001 to 2015, most of which originated in California, Oregon, Washington, and Wyoming. The CO2 emissions induced by droughts in California, Idaho, Oregon, and Washington amounted to 7%-12% of the total CO2 emissions from their respective power sectors, and the yearly rates were 8%-15% of their respective 2030 yearly targets outlined in the Clean Power Plan (CPP). Although there is uncertainty surrounding the CPP, its targets provide appropriate reference points for climate mitigation goals for the power sector. Given the global importance of hydroelectric and thermoelectric power, our results represent a critical step in quantifying the impact of drought on pollutant emissions from the power sector - and thus on mitigation targets - in other regions of the world.</p
Future hydro-climatic changes: Role of physical processes and model biases
No full textA large body of evidence unequivocally suggests that anthropogenic climate change is real and future hydro-climatic changes could have lasting impact on natural and human systems. However, due to the intrinsic complexity of the climate system and biases in the climate models, number of uncertainties associated with future climate change projections is quite large. Utilizing a suite of Earth-system modeling tools and statistical techniques, this dissertation seeks to investigate some of the most fundamental uncertainties in future climate change projections and hydrological impact assessments, within the context of large- and fine-scale processes and climate model biases. Using a bias correction technique and a multi-member ensemble of global climate model (GCM) simulations, I investigate the influence of sea surface temperature (SST) errors on future climate change projections. Results show that biases in SSTs distribution affect atmospheric circulation patterns and global precipitation distribution by amplifying atmospheric model errors. Furthermore, simulations with and without SSTs correction simulate statistically different future precipitation and temperature responses over many terrestrial and oceanic regions, implying that biases in SSTs distribution can significantly affect future global climate change projections. I further employ a high-resolution nested modeling system to investigate the uncertainty in global models’ projections for topographically complex South Asian summer monsoon region. The simulated dynamical features of the summer monsoon compared well with reanalysis data and observations. Further, I find that enhanced greenhouse forcing result in overall suppression of summer precipitation, a delay in monsoon onset, and an increase in the occurrence of monsoon break periods. Results provide evidence that both large- and fine-scale processes dictate South Asian summer monsoon response through changes in the large-scale monsoon flow and the fine-scale convective environment. I finally investigate the role of fine-scale climate change and the influence of climate model biases in hydrological impact assessment. I use high-resolution nested climate model simulations, covering the contiguous United States, and a bias correction technique to drive a hydrological model. Results indicate that biases significantly affect the simulated hydrological response to anthropogenic increase in greenhouse forcing. I find that the future hydrological response is heterogeneous across the United States. The fine-scale variation in the sign of hydrological changes highlights the role of fine-scale hydrological processes in dictating the future hydrological change. Further, I find that future hydrological response is dictated by both the absolute changes in precipitation and temperature and the changes in their daily extremes
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
