1,720,981 research outputs found
Present Energy Metabolism and the Future of Renewables
No full textMetabolism refers to the process of energy and material flows required to sustain the structure of an organism, ecosystem, or socioeconomic system (such as an urban area). The study of energy metabolism of an economy is insightful on both a local scale (city, region, or country) and on a global scale (world economy). A key feature contributing to the complexity of socioecologic systems is feedback, manifest in the presence of cycles. Material cycles in ecological systems are closed: mass is conserved throughout all cyclic paths. Furthermore, the incoming solar energy is maximally dissipated throughout cycles. Ecological systems have developed intricate couplings in order to reduce or eliminate energy or material waste, in juxtaposition to economic systems. What makes then an economy so inefficient compared to nature? On a local scale, the study of metabolism indicates that cities or countries are not a self-sustaining systems: they draw materials, energy, and information from the surrounding ecological and economic environment. Cyclic metabolic paths in the world economy are typically strictly (anti)- correlated to oil price. As showed in this chapter, the percentage of cycled material in trade was negatively correlated to oil price; this anti(correlation) scoring from 85 to 62% between 1960 and 2011. This shows that world metabolism is remarkably connected to the price of oil. In the long run, world metabolism is correlated to oil price because of the architecture of trading relationships. With low oil prices, the productive chain tends to unfold across countries, whereas with high oil prices the productive chain tends to shrink. Constraints and impediments to the complete success of renewable energy sources (RES) over fossil fuels are therefore based on certain factors which can be determined from a metabolic analysis of the economy: (1) energy source intensity, (2) the nonfungibility of oil in the transport sector, and (3) scale of production. Each factor raises particular questions which will be answered in this chapter. For example: Is the scale of the present economy/society (cities, countries, or world) strictly dependent on the intensity of fossil fuels? Can these scales of processes be sustained with energy sources at a lower intensity? What is the appropriate feedback between the scale of ecosystem services and scale of governance? Is circular economy attainable at the scale of the present global economy? These questions will be addressed in the light of energy metabolism
Complexification in the Energiewende
No full textThe path toward a low-carbon economy takes three main parallel roads: the efficiency of energy conversion, the reduction of energy use and the substitution of fossil-fuels with renewable energy. This chapter will focus mainly on this latter aspect of the problem by analyzing how a transition toward renewable energy can pose a new challenge to economy and governance in terms of complexification of the system. The fate of renewable energy sources (RES) crucially depends on the power sector for electricity is still the main vector for renewable energy. The main features of the ongoing transition toward a renewable energy system are: (1) lower intensity of energy sources; (2) high efficiency of conversion; (3) temporal discontinuity; (4) free access to local and more decentralized energy sources; (5) dramatic change in the economic concept of energy scarcity; (6) new, leading role of the network. Is this process leading to a higher complexification? To answer to this question, we will analyze this energy transition in the light of the concept of complexity and sustainability by looking at the history of economic development and societal change prompted by new energy sources and new form of energy conversions. A particular emphasis will be given to the case study of Germany and recent thrust toward an energiewende. Finally, it will be advocated the need for a new market of power aimed at decoupling the sites of electricity inlet and outlet overcoming the impending limits of RES energy that curbs their development
Ecological network analysis of a metabolic urban system based on input–output tables: Model development and case study for the city of Vienna
Full text linkInternational audienceThe rapid economic growth accompanied by health concerns and other global environmental problems in cities and regions has boosted the popularity of the 'urban metabolism' topic among academics and policymakers. Currently, 56.2% of the world's population lives in cities, accounting for 80% of the global GDP. It is projected that the current trend for world economic growth complemented by population growth and migration will continue affecting the resource production and consumption in cities and the impact this has on other urban areas. Here, we developed a new model approach that combines emergy input-output tables with ecological network analysis to investigate urban metabolism generally, and applied it to Vienna, Austria. This novel approach allows researchers to study the hierarchy of sectors and functional relationships along all possible metabolic paths of ecological and socioeconomic flows exchanging in an urban economy and between the urban economy and its environment. Then, using system-level analyses (flow and contribution analyses) we determined the status of the system components. Finally, the critical components responsible for the status (distribution structure of each industry) and emergy consumption of the other sectors were identified using pairwise control and utility analyses. The results showed that the "agriculture, forestry and fishing" and "mining and quarrying" sectors had the lowest ability to receive financial inputs from the other sectors, reflecting a shortage of agricultural and mining products to meet consumers' demand. Moreover, "agriculture, forestry and fishing" had the highest energy dependence on the other sectors, indicating the lack of self-sufficiency in energy use and the inability of this sector to deliver energy effectively to consuming sectors. This also implies the importance of this sector in achieving the energy efficiency improvement and economic development goals for consumer cities. This work contributes to the existing literature on ecological network analysis via an introduction of the two-step approach that combines the diagnosis of low activity components in the system taken from traditional ecological network analysis with the novel identification of components behind the low activity of the other components. In addition, direct and indirect control, and indirect utility analysis were introduced for the analysis of the impact of the direct energy and indirect pairwise economic control and relational interactions of sectors in cities. Finally, this work explored the inner workings of the service part of the urban economy to reveal the role each tertiary sector plays in the development of primary and secondary sectors of an urban economy. The model developed in this study will provide support for city managers and policymakers to guide resource consumption towards an efficient and sustainable urban metabolic system worldwide
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
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