375 research outputs found
Policy Means for Sustainable Energy Scenarios
Consequences of global warming are appearing much faster than assumed just a few years ago and irreversible ”tipping points” are few years ahead (IPCC, 2007; Hansen et al., 2008; Kopp et al., 2009). Despite long and tedious preparations for COP15 in December 2009 the final result (Copenhagen Accord, 2009) lacked sufficient concrete commitments for reduction of greenhouse gases (GHGs) after 2012 when the Kyoto Protocol expires. Human activities in their present form are strongly dependent on the supply of energy. A dominant part of the global energy supply is based on fossil fuels and a dominant part of the climate change is due to emission of CO2 from the use of fossil fuels. For simplicity, this paper focuses on CO2 emission from fossil fuels, but CO2 from deforestation as well as methane (CH4), laughing gas (N2O) and a number of industrial greenhouse gases should be included in a more comprehensive analysis. The paper will focus mainly on non-technological strategies for mitigation of climate change addressing such questions as national and international equity, limits to growth, population policies, and alternative employment policies
Effect of acute hypobaric hypoxia on the endothelial glycocalyx and digital reactive hyperemia in humans
Introduction: Hypoxia is associated with increased capillary permeability. This study tested whether acute hypobaric hypoxia involves degradation of the endothelial glycocalyx. Methods: We exposed 12 subjects to acute hypobaric hypoxia (equivalent to 4,500 m for 2-4 hours) and measured venous blood concentrations of biomarkers reflecting endothelial and glycocalyx degradation (catecholamines, syndecan-1, soluble CD40 ligand, protein C, soluble thrombomodulin, tissue-type plasminogen activators, histone-complexed DNA fragments and nitrite/nitrate). Endothelial function was assessed by the hyperemic response to brachial artery occlusion by peripheral arterial tonometry. Results: Compared with normoxic baseline levels, hypoxia increased concentrations of syndecan-1 from 22 (95% confidence interval: 17-27) to 25 (19-30) ng/ml (p < 0.02) and protein C from 76 (70-83) % to 81 (74-88) % (p < 0.02). Nitrite/nitrate decreased from 23 (18-27) μM at baseline to 19 (14-24) μM and 18 (14-21) μM in hypoxia and recovery, respectively (p < 0.05). Other biomarkers remained unchanged. The post-occlusion/pre-occlusion ratio (reactive hyperemia index, RHI) decreased from 1.80 (1.52–2.07) in normoxia to 1.62 (1.28–1.96) after 2 to 4 hours of hypobaric hypoxia and thereafter increased to 2.43 (1.99-2.86) during normoxic recovery (p < 0.01). Conclusions: The increase in syndecan-1 and protein C suggests that acute hypobaric hypoxia produces minor degree of glycocalyx degradation and overall cellular damage. After hypoxia RHI rebounded to higher than baseline levels suggesting improved endothelial functionality
Recommended from our members
Promoting electricity from renewable energy sources -- lessons learned from the EU, U.S. and Japan
The promotion of electricity generated from Renewable Energy Sources (RES) has recently gained high priority in the energy policy strategies of many countries in response to concerns about global climate change, energy security and other reasons. This chapter compares and contrasts the experience of a number of countries in Europe, states in the US as well as Japan in promoting RES, identifying what appear to be the most successful policy measures. Clearly, a wide range of policy instruments have been tried and are in place in different parts of the world to promote renewable energy technologies. The design and performance of these schemes varies from place to place, requiring further research to determine their effectiveness in delivering the desired results. The main conclusions that can be drawn from the present analysis are: (1) Generally speaking, promotional schemes that are properly designed within a stable framework and offer long-term investment continuity produce better results. Credibility and continuity reduce risks thus leading to lower profit requirements by investors. (2) Despite their significant growth in absolute terms in a number of key markets, the near-term prognosis for renewables is one of modest success if measured in terms of the percentage of the total energy provided by renewables on a world-wide basis. This is a significant challenge, suggesting that renewables have to grow at an even faster pace if we expect them to contribute on a significant scale to the world's energy mix
- …