1,721,002 research outputs found
Environmental, Social and Economic Sustainability of Biobased Plastics. Bio-polyethylene from Brazil and polylactic acid from the U.S.
Full text linkSUMMARY
Ever depleting fossil resources, growing fossil feedstock prices and global environmental impact associated with continuously rising greenhouse gas emissions have led to increased attention for biobased products as alternatives for the present fossil-based ones. It is therefore important for scientists and academics to provide knowledge and explore practical routes for the sustainable transition towards biobased alternatives. This research focuses on the replacement of fossil-based polyethylene (fossil-PE) by biobased PE (bio-PE) from Brazilian sugarcane and polylactic acid (PLA) from US corn. The report gives an outlook on such a shift towards a sustainable biobased economy. The aim of this research is to assess the characteristics of the biobased product supply chains which could provide in the demand for biobased polyethylene and polylactic acid for the Netherlands on environmental, social and economic aspects in order to contribute to the existing fundamental research on biobased products. This led to the main research question:
How sustainable are the supply chains for biobased polyethylene and polylactic acid, which could meet the current demand for fossil-based polyethylene in the Netherlands, and how does this compare to the supply chain of fossil-based polyethylene?
An analytical framework is developed along which the three dimensions of sustainability can be evaluated; environmental (greenhouse gas emissions, biodiversity and the local environment), social (competition for food, welfare and wellbeing) and economic sustainability (market price). The report focuses on the demand for bio-PE and PLA which could replace the current Dutch demand for PE of approximately 500 kiloton per year.
The report shows that on environmental sustainability, bio-PE outperforms fossil-PE and PLA. Life cycle greenhouse gas emissions are particularly low for bio-PE due to the extensive use of bagasse as energy supply. PLA associated greenhouse gas emissions are slightly less than the greenhouse gas emissions for fossil-PE. Depending on the type of land that is converted to biomass feedstock, greenhouse gas emissions can increase due to the release of carbon from decaying biomass and the loss of soil organic carbon. This effect can be significant if rainforest is converted either by direct or indirect land use change. Even so, considering the relatively small demand, enough land is available in Brazil for the production of the biobased products without endangering bio-diverse regions. The main impact of biobased products on the local environment is the imbalance of NPK nutrients and for fossil-based products on- and offshore oil spills.
The main concern with regard to the social sustainability was found in the exploitation of sugarcane and corn field workers. Case reports were found on slavery and exploitation, although no structural proof was found. For fossil-PE, decrease of the local welfare and wellbeing was found for several countries producing naphtha. Competition for food was considered as one of the main indicators. It is found that there is no competition for food if only the Dutch demand is considered, but a worldwide demand for multiple biobased products would inevitably lead to competition for food. This stresses the importance of alternative biomass sources that do not impact food supply, such as lignocelluloses.
Even though bio-PE shows more favourable results than fossil-PE, biobased products are still unsustainable due to the high market price with respect to the biobased product. With current feedstock prices, market prices for bio-PE and PLA are respectively 40% to 60% more expensive than fossil-PE. The price imbalance can be partially explained by the fact that the costs of environmental degradation are externalized for fossil-based products. Internalizing these externalities by for instance green VAT or carbon tax would level the playing field for biobased products. A reduced green vat of 6% for “green” products (19% for normal products) would reduce the difference to 25% and 40% for bio-PE and PLA respectively. Additionally implementing a carbon tax of 50 USD/t CO2 would reduce the difference even further to 15% and 35% for bio-PE and PLA respectively.
Impact of Sea Level Rise for the Conterminous United States. An analysis on Inhabitant Displacement and GDP Production Impediment due to Land Inundation
Full text link
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
- …
