960 resultados para EMERGY INDICES


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The quality and the power of human activities affect the external environment in different ways that can be measured and evaluated by means of several approaches and indicators. While the scientific community has been publishing several proposals for sustainable development indicators, there is still no consensus regarding the best approach to the use of these indicators and their reliability to measure sustainability. It is important, therefore, to question the effectiveness of sustainable development indicators in an effort to continue in the search for sustainability. This paper compares the results obtained with emergy accounting with five global Sustainability Metrics (SMs) proposed in the literature to verify if metrics are communicating coherent and similar information to guide decision makers towards sustainable development. Results obtained using emergy indices are discussed with the aid of emergy ternary diagrams. Metrics are confronted with emergy results, and the degree of variability among them is analyzed using a correlation matrix created for the Mercosur nations. The contrast of results clearly shows that metrics arrive at different interpretations about the sustainability of the nations studied, but also that some metrics may be grouped and used more prudently. Mercosur is presented as a case study to highlight and explain the discrepancies and similarities among Sustainability Metrics, and to expose the extent of emergy accounting. (C) 2010 Elsevier Ltd. All rights reserved.

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This paper presents an environmental emergy-based diagnosis of Brazil compared with Russia, India, China, South Africa and United States. Reflections on the Brazilian sustainable development are presented and discussed based on the evaluations published since 1979. The variation of the emergy per capita for Brazil from 1979 to 2007 indicates that the country's growth is tied to the exploitation of non renewable natural resources which do not directly reflect in the welfare of the population. The total emergy exported per unit of gross domestic product increased in the period, suggesting that the country exports more emergy than that contained in the money received for the exportation. With the help of the emergy indices, the future development of Brazil is explored and discussed. The comparison among the BRICS (Brazil, Russia, India, China and South Africa) countries and United States indicates that what may be appropriate and usable within one country may not be within another and that to achieve the global sustainability two concomitant actions may occur: (i) the reduction of the total emergy use in developed economies, and (ii) the reduction of indigenous resources exportation in developing economies. (C) 2013 Elsevier Ltd. All rights reserved.

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The use of microalgae and cyanobacteria for the production of biofuels and other raw materials is considered a very promising sustainable technology due to the high areal productivity, potential for CO2 fixation and use of non-arable land. The production of oil by microalgae in a large scale plant was studied using emergy analysis. The joint transformity calculated for the base scenario was 1.32E + 5 sej/J, the oil transformity was 3.51E + 5 sej/J, the emergy yield ratio (EYR) was 1.09 and environmental loading ratio was 11.10 and the emergy sustainability index (ESI) was 0.10, highlighting some of the key challenges for the technology such as high energy consumption during harvesting, raw material consumption and high capital and operation costs. Alternatives scenarios and the sensitivity to process improvements were also assessed, helping prioritize further research based on sustainability impact. (C) 2012 Elsevier Ltd. All rights reserved.

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O Montado, em Portugal, é um complexo sistema silvopastoril de uso da terra, tipicamente Mediterrânico, com diversos estratos de vegetação, incluindo sobreiro e azinheira em várias densidades, onde é frequente a criação de gado. Esta actividade pecuária beneficia das pastagens no sob-coberto, de algumas espécies arbustivas e também das bolotas que caem do coberto arbóreo, contribuindo para evitar a invasão da pastagem por matos. No entanto, dependendo da sua gestão, este gado pode comprometer a regeneração do sistema. Nos últimos 20 anos, os subsídios no âmbito da Política Agrícola Comum da União Europeia têm promovido a criação de gado bovino em detrimento de outras espécies e raças mais leves, bem como a intensificação desta produção. Esta intensificação pode impossibilitar a regeneração natural das árvores ameaçando o equilíbrio do Montado. Por esta razão é necessária uma avaliação focada na criação de gado bovino e nos seus impactos sobre o sistema. O objectivo deste estudo foi obter uma melhor compreensão do funcionamento de uma exploração silvopastoril num sistema de Montado, através da aplicação do Método de Avaliação Emergética e do cálculo de índices emergéticos. Pretende-se assim compreender a melhor forma de o gerir, bem como conceber estratégias que maximizem o fluxo de emergia na exploração. Uma comparação deste método com a avaliação económica permitiu perceber em que aspectos esta pode ser complementada pelo método da avaliação emergética. O método da avaliação emergética permite a avaliação de sistemas multifuncionais complexos à escala de uma exploração individual, fornecendo informação extra em relação à avaliação económica como a renovabilidade dos inputs do sistema, ou a quantidade de fluxos livres da natureza que é valorada por preços de mercado. Este método permite a integração das emternalidades e das externalidades à contabilização económica, transformando uma avaliação tendencialmente separada do seu sistema mais vasto, numa avaliação de um sistema em conexão com aqueles mais vastos nos quais se integra; Abstract: The Montado, in Portugal, is a complex silvo-pastoral system of land use, typically Mediterranean, with different strata of vegetation, including cork and holm oaks in various densities, and where cattle rearing is common. This stockfarm benefits from the herbaceous layer under the trees, as well as from some species in the shrub layer, and also from the acorns faling down from the tree cover, while contributing to prevent the invasion of pastures by shrubs. Nevertheless, depending on its management, livestock can affect the system regeneration. Over the past 20 years, subsidies of the European Union's common agricultural policy have promoted the cattle rearing at expense of other lighter species and breeds, as well as its intensification. This intensification may impair the natural regeneration of trees threatening the balance of the Montado. Therefore an assessment focused on cattle and their impact on the system is required. The purpose of this study was to obtain a better understanding of the functioning of a silvo-pastoral farm in a Montado system, by applying the emergy evaluation method and through the calculation of emergy indices. It is intended to understand the best way to manage and design strategies that maximize the emergy flow on the farm. A comparison of this method with the economic evaluation allowed to realize in what aspects it can be complemented by the emergy evaluation method. The emergy evaluation method alows the assessment of complex multi-functional systems at the scale of an individual farm, providing extra information in relation to economic avaluation as the renewability of the inputs to a system and the amount of free flows of nature that is valued by market prices. This method allows the integration of the emternalities and the externalities to the economic accounting, transforming an evaluation tended separated from its wider system, in an evaluation of a system in connection with the larger ones on which it is incorporated.

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The Mediterranean silvo-pastoral system known as Montado, in Portugal, is a complex land use system composed of an open tree stratum in various densities and an herbaceous layer, used for livestock grazing. Livestock also profit from the acorns, and the grazing contributes to avoid shrub encroachment. In the last 20 years, subsidies from the European Union have greatly promoted cattle rearing in this system and the introduction of heavy breeds, at the expense of sheep, goats or the native cattle breeds. The balance of the traditional system is thus threatened, and a precise assessment of the balance between the different components of the system, therefore is highly needed. The goal of this study was to gain a better under- standing of a Montado farm system with cattle rearing as the major economic activity by applying the emergy evaluation method to calculate indices of yield, investment, environmental loading and sustainability. By integrating different ecosystem components, the emergy evaluation method allows a comprehensive evaluation of this complex and multifunctional system at the scale of an individual farm. This method provides a set of indices that can help us understand the system and design management strategies that maximize emergy flow in the farm. In this paper, we apply the emergy evaluation method to a Montado farm with cattle rearing, as a way to gain a better understanding of this system at the farm scale. The value for the transformity of veal (2.66E?06 sej J-1) is slightly higher, when compared to other systems producing protein. That means that the investment of nature and man in this product was higher and it requires a premium price on the market. The renewa- bility for Holm Oaks Farm (49 %), lower than for other similar systems, supports the assumption that this is a farm in which, comparing with others, the number of purchased inputs in relation to renewable inputs provided by nature, is higher. The Emergy Investment Ratio is 0.91 for cattle rearing compared to a value of 0.49 for cork and 0.43 for firewood harvesting, making it clear that cattle rearing is a more labor demanding activity comparing with extractive activities as cork and firewood harvesting.

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This paper analyzes the performance of some of the widely used voltage stability indices, namely, singular value, eigenvalue, and loading margin with different static load models. Well-known ZIP model is used to represent loads having components with different power to voltage sensitivities. Studies are carried out on a 10-bus power system and the New England 39-bus power system models. The effects of variation of load model on the performance of the voltage stability indices are discussed. The choice of voltage stability index in the context of load modelling is also suggested in this paper.

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The two outcome indices described in a companion paper (Sanson et al., Child Indicators Research, 2009) were developed using data from the Longitudinal Study of Australian Children (LSAC). These indices, one for infants and the other for 4 year to 5 year old children, were designed to fill the need for parsimonious measures of children’s developmental status to be used in analyses by a broad range of data users and to guide government policy and interventions to support young children’s optimal development. This paper presents evidence from Wave 1data from LSAC to support the validity of these indices and their three domain scores of Physical, Social/Emotional, and Learning. Relationships between the indices and child, maternal, family, and neighborhood factors which are known to relate concurrently to child outcomes were examined. Meaningful associations were found with the selected variables, thereby demonstrating the usefulness of the outcome indices as tools for understanding children’s development in their family and socio-cultural contexts. It is concluded that the outcome indices are valuable tools for increasing understanding of influences on children’s development, and for guiding policy and practice to optimize children’s life chances.

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The Longitudinal Study of Australian Children (LSAC) is a major national study examining the lives of Australian children, using a cross-sequential cohort design and data from parents, children, and teachers for 5,107 infants (3–19 months) and 4,983 children (4–5 years). Its data are publicly accessible and are used by researchers from many disciplinary backgrounds. It contains multiple measures of children’s developmental outcomes as well as a broad range of information on the contexts of their lives. This paper reports on the development of summary outcome indices of child development using the LSAC data. The indices were developed to fill the need for indicators suitable for use by diverse data users in order to guide government policy and interventions which support young children’s optimal development. The concepts underpinning the indices and the methods of their development are presented. Two outcome indices (infant and child) were developed, each consisting of three domains—health and physical development, social and emotional functioning, and learning competency. A total of 16 measures are used to make up these three domains in the Outcome Index for the Child Cohort and six measures for the Infant Cohort. These measures are described and evidence supporting the structure of the domains and their underlying latent constructs is provided for both cohorts. The factorial structure of the Outcome Index is adequate for both cohorts, but was stronger for the child than infant cohort. It is concluded that the LSAC Outcome Index is a parsimonious measure representing the major components of development which is suitable for non-specialist data users. A companion paper (Sanson et al. 2010) presents evidence of the validity of the Index.

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In a power network, when a propagation energy wave caused by a disturbance hits a weak link, a reflection is appeared and some of energy is transferred across the link. In this work, an analytical descriptive methodology is proposed to study the dynamical stability of a large scale power system. For this purpose, the measured electrical indices (angle, or voltage/frequency) following a fault in different points among the network are used, and the behaviors of the propagated waves through the lines, nodes and buses are studied. This work addresses a new tool for power system stability analysis based on a descriptive study of electrical measurements. The proposed methodology is also useful to detect the contingency condition and synthesis of an effective emergency control scheme.

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The multifractal properties of two indices of geomagnetic activity, D st (representative of low latitudes) and a p (representative of the global geomagnetic activity), with the solar X-ray brightness, X l , during the period from 1 March 1995 to 17 June 2003 are examined using multifractal detrended fluctuation analysis (MF-DFA). The h(q) curves of D st and a p in the MF-DFA are similar to each other, but they are different from that of X l , indicating that the scaling properties of X l are different from those of D st and a p . Hence, one should not predict the magnitude of magnetic storms directly from solar X-ray observations. However, a strong relationship exists between the classes of the solar X-ray irradiance (the classes being chosen to separate solar flares of class X-M, class C, and class B or less, including no flares) in hourly measurements and the geomagnetic disturbances (large to moderate, small, or quiet) seen in D st and a p during the active period. Each time series was converted into a symbolic sequence using three classes. The frequency, yielding the measure representations, of the substrings in the symbolic sequences then characterizes the pattern of space weather events. Using the MF-DFA method and traditional multifractal analysis, we calculate the h(q), D(q), and τ (q) curves of the measure representations. The τ (q) curves indicate that the measure representations of these three indices are multifractal. On the basis of this three-class clustering, we find that the h(q), D(q), and τ (q) curves of the measure representations of these three indices are similar to each other for positive values of q. Hence, a positive flare storm class dependence is reflected in the scaling exponents h(q) in the MF-DFA and the multifractal exponents D(q) and τ (q). This finding indicates that the use of the solar flare classes could improve the prediction of the D st classes.

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The purpose of this study was to investigate the effects of whole-body cryotherapy (WBC) on proprioceptive function, muscle force recovery following eccentric muscle contractions and tympanic temperature (TTY). Thirty-six subjects were randomly assigned to a group receiving two 3-min treatments of −110 ± 3 °C or 15 ± 3 °C. Knee joint position sense (JPS), maximal voluntary isometric contraction (MVIC) of the knee extensors, force proprioception and TTY were recorded before, immediately after the exposure and again 15 min later. A convenience sample of 18 subjects also underwent an eccentric exercise protocol on their contralateral left leg 24 h before exposure. MVIC (left knee), peak power output (PPO) during a repeated sprint on a cycle ergometer and muscles soreness were measured pre-, 24, 48 and 72 h post-treatment. WBC reduced TTY, by 0.3 °C, when compared with the control group (P<0.001). However, JPS, MVIC or force proprioception was not affected. Similarly, WBC did not effect MVIC, PPO or muscle soreness following eccentric exercise. WBC, administered 24 h after eccentric exercise, is ineffective in alleviating muscle soreness or enhancing muscle force recovery. The results of this study also indicate no increased risk of proprioceptive-related injury following WBC.