6 resultados para Limits to arbitrage

em Aston University Research Archive


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In this article we compare the current debate about global warming with the earlier discourse of Limits to Growth (LtG) of the 1970's. We are especially interested in the similarities of and differences between the two cases and therefore compare the policy challenges and lessons to be drawn. While the two debates differ on important issues, they share a technocratic orientation to public policy, and susceptibility to similar pitfalls. In both debates alarming scenarios about future catastrophes play an important role. We suggest that climate change policy discourse needs to focus more closely on the social, economic, and political dimensions of climate change, as opposed to its excessive emphasis on emission reduction targets. We also argue that an excessive faith in the market mechanisms to supply global warming mitigation technologies is problematic. In this respect, we provide a reality check regarding the political implications of emission targets and timetables and suggest how policy issues can be moved forward.

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Transcranial direct current stimulation (tDCS) is a method of non-invasive brain stimulation widely used to modulate cognitive functions. Recent studies, however, suggests that effects are unreliable, small and often non-significant at least when stimulation is applied in a single session to healthy individuals. We examined the effects of frontal and temporal lobe anodal tDCS on naming and reading tasks and considered possible interactions with linguistic activation and selection mechanisms as well possible interactions with item difficulty and participant individual variability. Across four separate experiments (N, Exp 1A = 18; 1B = 20; 1C = 18; 2 = 17), we failed to find any difference between real and sham stimulation. Moreover, we found no evidence of significant effects limited to particular conditions (i.e., those requiring suppression of semantic interference), to a subset of participants or to longer RTs. Our findings sound a cautionary note on using tDCS as a means to modulate cognitive performance. Consistent effects of tDCS may be difficult to demonstrate in healthy participants in reading and naming tasks, and be limited to cases of pathological neurophysiology and/or to the use of learning paradigms.

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Fast pyrolysis liquid or bio-oil has been used in engines with limited success. It requires a pilot fuel and/or an additive for successful combustion and there are problems with materials and liquid properties. It is immiscible with all conventional hydrocarbon fuels. Biodiesel, a product of esterification of vegetable oil with an alcohol, is widely used as a renewable liquid fuel as an additive to diesel at up to 20%. There are however limits to its use in conventional engines due to poor low temperature performance and variability in quality from a variety of vegetable oil qualities and variety of esterification processes. Within the European Project Bioliquids-CHP - a joint project between the European Commission and Russia - a study was undertaken to develop small scale CHP units based on engines and microturbines fuelled with bioliquids from fast pyrolysis and methyl esters of vegetable oil. Blends of bio-oil and biodiesel were evaluated and tested to overcome some of the disadvantages of using either fuel by itself. An alcohol was used as the co-solvent in the form of ethanol, 1-butanol or 2-propanol. Visual inspection of the blend homogeneity after 48 h was used as an indicator of the product stability and the results were plotted in a three phase chart for each alcohol used. An accelerated stability test was performed on selected samples in order to predict its long term stability. We concluded that the type and quantity of alcohol is critical for the blend formation and stability. Using 1-butanol gave the widest selection of stable blends, followed by blends with 2-propanol and finally ethanol, thus 1-butanol blends accepted the largest proportion of bio-oil in the mixture. © 2013 Elsevier Ltd. All rights reserved.

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In this paper we explore the relationship between the individual decision to become an entrepreneur and the institutional context. We pinpoint the critical roles of property rights and the size of the state sector for entrepreneurial activity and test the relationships empirically by combining country-level institutional indicators for 44 countries with working age population survey data taken from the Global Enterprise Monitor. A methodological contribution is the use of factor analysis to reduce the statistical problems with the array of highly collinear institutional indicators. We find that the key institutional features that enhance entrepreneurial activity are indeed the rule of law and limits to the state sector. However, these results are sensitive to the level of development.

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This book challenges the assumption that it is bad news when the economy doesn’t grow. For decades, it has been widely recognized that there are ecological limits to continuing economic growth and that different ways of living, working and organizing our economies are urgently required. This urgency has increased since the financial crash of 2007–2008, but mainstream economists and politicians are unable to think differently. The authors of this book demonstrate why our economic system demands ecologically unsustainable growth and the pursuit of more ‘stuff’. They believe that what matters is quality, not quantity – a better life based on having fewer material possessions, less production and less work. Such a way of life will emphasize well‑being, community, security and ‘conviviality’. That is, more real wealth. The book will therefore appeal to everyone curious as to how a new post-growth economics can be conceived and enacted. It will be of particular interest to policy makers, politicians, businesspeople, trade unionists, academics, students, journalists and a wide range of people working in the not-for-profit sector. All of the contributors are leading thinkers on green issues and members of the new think-tank Green House.

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In this presentation we will discuss the implications of the so called Nonlinear Shannon Limit. We will compare technologies including new fibres for long haul transmission and techniques to expand the capacity of existing standard single mode fibres.