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1.
The effect of macroeconomic fluctuations on individual health remains highly debated. We estimate the effect of the business cycle on health and health behavior in the U.S. using the NLSY79 panel data for 11,406 respondents between 1979 and 2014. Most of our survey respondents have no chronic illness in 1979, and develop these conditions during the sample period. This allows us to estimate the true effect of economic fluctuation on the likelihood of developing chronic conditions. The results indicate a considerable difference in the cyclic variation of chronic diseases. After controlling for innate individual characteristics such as family health history, and unobserved regional characteristics, we find that obesity decreases during economic downturns, while diabetes, hypertension, and congestive heart failure increase. Sub-sample analyses show that Blacks are more likely to develop diabetes and hypertension and are less likely to develop obesity during economic downturns than other racial groups. The incidence of obesity declines during recessions for women, while males are more likely to develop diabetes. Income loss, particularly among Blacks, and lack of change in physical activity mediate these differential effects. 相似文献
2.
Purpose
The construction industry has considerable impacts on the environment, economy, and society. Although quantifying and analyzing the sustainability implications of the built environment is of great importance, it has not been studied sufficiently. Therefore, the overarching goal of this study is to quantify the overall environmental, economic, and social impacts of the U.S. construction sectors using an economic input–output-based sustainability assessment framework.Methods
In this research, the commodity-by-industry supply and use tables published by the U.S. Bureau of Economic Analysis, as part of the International System of National Accounts, are merged with a range of environmental, economic, and social metrics to develop a comprehensive sustainability assessment framework for the U.S. construction industry. After determining these sustainability assessment metrics, the direct and indirect sustainability impacts of U.S construction sectors have been analyzed from a triple bottom-line perspective.Results
When analyzing the total sustainability impacts by each construction sector, “Residential Permanent Single and Multi-Family Structures" and "Other Non-residential Structures" are found to have the highest environmental, economic, and social impacts in comparison with other construction sectors. The analysis results also show that indirect suppliers of construction sectors have the largest sustainability impacts compared with on-site activities. For example, for all U.S. construction sectors, on-site construction processes are found to be responsible for less than 5 % of total water consumption, whereas about 95 % of total water use can be attributed to indirect suppliers. In addition, Scope 3 emissions are responsible for the highest carbon emissions compared with Scopes 1 and 2. Therefore, using narrowly defined system boundaries by ignoring supply chain-related impacts can result in underestimation of triple bottom-line sustainability impacts of the U.S. construction industry.Conclusions
Life cycle assessment (LCA) studies that consider all dimensions of sustainability impacts of civil infrastructures are still limited, and the current research is an important attempt to analyze the triple bottom-line sustainability impacts of the U.S. construction sectors in a holistic way. We believe that this comprehensive sustainability assessment model will complement previous LCA studies on resource consumption of U.S. construction sectors by evaluating them not only from environmental standpoint, but also from economic and social perspectives. 相似文献3.
Krieger LM 《Plastic and reconstructive surgery》2002,110(5):1347-1352
Periods of economic downturn place special demands on the plastic surgeon whose practice involves a large amount of cosmetic surgery. When determining strategy during difficult economic times, it is useful to understand the macroeconomic background of these downturns and to draw lessons from businesses in other service industries. Business cycles and monetary policy determine the overall environment in which plastic surgery is practiced. Plastic surgeons can take both defensive and proactive steps to maintain their profits during recessions and to prepare for the inevitable upturn. Care should also be taken when selecting pricing strategy during economic slowdowns. 相似文献
4.
Lesley P. Baggett Sean P. Powers Robert D. Brumbaugh Loren D. Coen Bryan M. DeAngelis Jennifer K. Greene Boze T. Hancock Summer M. Morlock Brian L. Allen Denise L. Breitburg David Bushek Jonathan H. Grabowski Raymond E. Grizzle Edwin D. Grosholz Megan K. La Peyre Mark W. Luckenbach Kay A. McGraw Michael F. Piehler Stephanie R. Westby Philine S. E. zu Ermgassen 《Restoration Ecology》2015,23(6):737-745
Restoration of degraded ecosystems is an important societal goal, yet inadequate monitoring and the absence of clear performance metrics are common criticisms of many habitat restoration projects. Funding limitations can prevent adequate monitoring, but we suggest that the lack of accepted metrics to address the diversity of restoration objectives also presents a serious challenge to the monitoring of restoration projects. A working group with experience in designing and monitoring oyster reef projects was used to develop standardized monitoring metrics, units, and performance criteria that would allow for comparison among restoration sites and projects of various construction types. A set of four universal metrics (reef areal dimensions, reef height, oyster density, and oyster size–frequency distribution) and a set of three universal environmental variables (water temperature, salinity, and dissolved oxygen) are recommended to be monitored for all oyster habitat restoration projects regardless of their goal(s). In addition, restoration goal‐based metrics specific to four commonly cited ecosystem service‐based restoration goals are recommended, along with an optional set of seven supplemental ancillary metrics that could provide information useful to the interpretation of prerestoration and postrestoration monitoring data. Widespread adoption of a common set of metrics with standardized techniques and units to assess well‐defined goals not only allows practitioners to gauge the performance of their own projects but also allows for comparison among projects, which is both essential to the advancement of the field of oyster restoration and can provide new knowledge about the structure and ecological function of oyster reef ecosystems. 相似文献
5.
Saif Ahmad Tim Ramsay Lothar Huebsch Sarah Flanagan Sheryl McDiarmid Izmail Batkin Lauralyn McIntyre Sudhir R. Sundaresan Donna E. Maziak Farid M. Shamji Paul Hebert Dean Fergusson Alan Tinmouth Andrew J. E. Seely 《PloS one》2009,4(8)
Background
Early diagnosis of sepsis enables timely resuscitation and antibiotics and prevents subsequent morbidity and mortality. Clinical approaches relying on point-in-time analysis of vital signs or lab values are often insensitive, non-specific and late diagnostic markers of sepsis. Exploring otherwise hidden information within intervals-in-time, heart rate variability (HRV) has been documented to be both altered in the presence of sepsis, and correlated with its severity. We hypothesized that by continuously tracking individual patient HRV over time in patients as they develop sepsis, we would demonstrate reduced HRV in association with the onset of sepsis.Methodology/Principal Findings
We monitored heart rate continuously in adult bone marrow transplant (BMT) patients (n = 21) beginning a day before their BMT and continuing until recovery or withdrawal (12±4 days). We characterized HRV continuously over time with a panel of time, frequency, complexity, and scale-invariant domain techniques. We defined baseline HRV as mean variability for the first 24 h of monitoring and studied individual and population average percentage change (from baseline) over time in diverse HRV metrics, in comparison with the time of clinical diagnosis and treatment of sepsis (defined as systemic inflammatory response syndrome along with clinically suspected infection requiring treatment). Of the 21 patients enrolled, 4 patients withdrew, leaving 17 patients who completed the study. Fourteen patients developed sepsis requiring antibiotic therapy, whereas 3 did not. On average, for 12 out of 14 infected patients, a significant (25%) reduction prior to the clinical diagnosis and treatment of sepsis was observed in standard deviation, root mean square successive difference, sample and multiscale entropy, fast Fourier transform, detrended fluctuation analysis, and wavelet variability metrics. For infected patients (n = 14), wavelet HRV demonstrated a 25% drop from baseline 35 h prior to sepsis on average. For 3 out of 3 non-infected patients, all measures, except root mean square successive difference and entropy, showed no significant reduction. Significant correlation was present amongst these HRV metrics for the entire population.Conclusions/Significance
Continuous HRV monitoring is feasible in ambulatory patients, demonstrates significant HRV alteration in individual patients in association with, and prior to clinical diagnosis and treatment of sepsis, and merits further investigation as a means of providing early warning of sepsis. 相似文献6.
专业化茶叶种植影响下的农业生态系统服务功能价值评价——以福建省安溪县为例 总被引:3,自引:0,他引:3
饮茶已逐渐成为世界潮流与时尚,不断扩大的茶叶需求正不断刺激茶叶的增产,茶叶经济发展受到世界瞩目,但关于规模化、专业化茶叶种植对农业生态系统的影响却未得到相应的关注。为研究规模不断扩大的专业化茶叶种植对农业生态系统的影响,以专业化茶叶种植大县安溪县为研究对象,通过构建由供给、调节和支持正、负服务组成的农业生态系统服务功能价值评价指标体系,结合能值法,从不同专业化茶叶种植水平、不同农业种植结构、不同地貌类型三个方面进行评估分析。研究结果表明:(1)安溪县以专业化茶叶种植为主的农业生态系统中供给、调节和支持三大服务功能的正服务价值都大于负服务价值,系统以提供正服务为主;(2)专业化茶叶种植具有较高的经济效益和较好的气体、气候调节能力,对农业生态系统中的供给与调节功能具有正效应;(3)但专业化种植过程中造成的土壤流失情况也较为严重,对农业生态系统支持功能的负面影响较大;(4)"茶-蔬"、"茶-果"等复合生态茶树种植结构有利于提高农业生态系统服务功能,实现茶叶经济与农业生态系统的和谐发展。 相似文献
7.
生物入侵已经成为全球面临的三大环境问题之一。鱼类入侵现象也随全球经济一体化的进程日益严重。本文综述了全球淡水鱼类入侵的现状和研究进展, 包括鱼类入侵的定义及分布、入侵途径和机制、产生的生态和社会经济影响以及预防措施等。据统计, 目前全球外来鱼类达624种, 该数量超过30年前的两倍。外来鱼类主要通过水产养殖(51%)、观赏渔业(21%)、休闲垂钓(12%)、渔业捕捞运输(7%)等多种途径被引进。入侵鱼类对本地种产生了捕食、种内种间竞争、杂交和疾病传播等负面影响, 破坏本地生态系统, 但是其正面的生态及社会经济影响也不可忽略。近20年来全球鱼类入侵日益受到重视, 相关论文发表数量翻了8倍。值得提出的是, 近10年来全球鱼类入侵风险评价系统的研究显著增加, 一些鱼类入侵模型已应用于五大洲的多个国家。我国淡水外来鱼类共计439种。然而, 我国关于鱼类入侵的研究起步较晚, 发表文献数仅占全球的3.7%, 且主要研究方向仍集中在入侵物种的分布及生物学特性等基础研究上, 缺乏对于鱼类入侵机制及风险评价预测的研究。因此, 我们建议: (1)开展全国范围的本底调查并建立数据库, 实现数据共享, 明确鱼类入侵的历史与分布现状; (2)联合多个政府部门和机构, 对鱼类入侵进行长期观测, 从整个水生生态系统的角度出发, 深入了解其入侵机制及其产生的正面和负面生态和社会经济影响; (3)加强增殖放流的科学研究和管理; (4)构建区域性外来鱼类入侵风险评价系统, 有效预测鱼类入侵活动, 评价入侵种的危害, 并为相关政府部门的决策提供科学依据。 相似文献
8.
Pappaioanou M Gramer M 《ILAR journal / National Research Council, Institute of Laboratory Animal Resources》2010,51(3):268-280
In April 2009, a novel influenza A subtype H1N1 triple reassortant virus (novel H1N1 2009), composed of genes from swine, avian, and human influenza A viruses, emerged in humans in the United States and Mexico and spread person-to-person around the world to become the first influenza pandemic of the 21st century. The virus is believed to have emerged from a reassortment event involving a swine virus some time in the past 10 to 20 years, but pigs, pork, and pork products have not been involved with infection or spread of the virus to or among people. Because countries quickly implemented recently developed pandemic influenza plans, the disease was detected and reported and public health authorities instituted control measures in a timely fashion. But the news media's unfortunate and inappropriate naming of the disease as the "swine flu" led to a drop in the demand for pork and several countries banned pork imports from affected countries, resulting in serious negative economic impacts on the pork industry. With the continual circulation and interspecies transmission of human, swine, and avian influenza viruses in countries around the world, there are calls for strengthening influenza surveillance in pigs, birds, and other animals to aid in monitoring and assessing the risk of future pandemic virus emergence involving different species. We identify and discuss several lessons to be learned from pandemic H1N1 2009 from a One Health perspective, as stronger collaboration among human, animal, and environmental health sectors is necessary to more effectively prevent or detect and respond to influenza pandemics and thus improve human, animal, and environmental health and well-being. 相似文献
9.
Battistuzzi G Borsari M Canters GW de Waal E Leonardi A Ranieri A Sola M 《Biochemistry》2002,41(48):14293-14298
The thermodynamic parameters of the conformational transition occurring at low pH (acid transition, AT) in blue copper proteins, involving protonation and detachment from the Cu(I) ion of one histidine ligand, have been determined electrochemically for spinach and cucumber plastocyanins, Rhus vernicifera stellacyanin, cucumber basic protein (CBP), and Paracoccus versutus amicyanin. These data were obtained from direct protein electrochemistry experiments carried out at varying pH and temperature. For all species but CBP, the overall conformational change turns out to be exothermic. The entropy change is remarkably species-dependent. In particular, we found that (i) the balance of bond breaking/formation favors the acid transition in plastocyanins, which show remarkably negative DeltaH degrees '(AT) values, and (ii) the transition enthalpy turns out to be much less negative (or even positive) for the two phytocyanins (stellacyanin and CBP): for these species, the transition turns out to be observable thanks to the favorable (positive) entropy change. Thus, it is apparent that the thermodynamic "driving force" for this transition is enthalpic for the plastocyanins and entropic for the phytocyanins. Amicyanin is an intermediate case in which both enthalpic and entropic terms favor the transition. Under the assumption that the transition entropy originates from solvent reorganization effects, which are known to involve compensative enthalpy and entropy changes, the free energy change of the transition would also correspond to the enthalpy change due to bond breaking/formation in the first coordination sphere of the metal and in its immediate environment. Indeed, this term turns out to be very similar for the proteins investigated, in line with the conservation of the Cu(I)-His bond strengths in these species, except for amicyanin, for which the greater exothermicity of the transition can be ascribed to peculiar features of the active site. 相似文献
10.
《植物生态学报》2013,24(6):672
Biological invasion is now considered one of the three major environmental issues worldwide. Freshwater fish invasion becomes more serious with globalization of the world economy. We reviewed the current status of global freshwater fish invasions and discussed the definitions, distributions, introduction pathways, mechanisms, ecological and economic impacts, and risk assessments of freshwater fish invasions. Non-native fish are mainly introduced through food aquaculture (51%), as ornamental fish (21%), or for sport fishing (12%) and fisheries (7%). The number of introduced fish has reached 624 species, doubled the number found thirty years ago. Successful invasions may bring many negative ecological consequences, such as predation, hybridization, structure and function alteration of local freshwater ecosystems, as well as diseases transmission. However, it also brings positive biological and economic values. The number of fish invasion studies has increased eight times over the last 20 years, with studies mainly focusing on biology and the biological impact of invasive fish species. Risk assessments of freshwater fish invasions were studied over the last 10 years, and fish invasiveness screening models have been applied in countries of five continents. The number of non-native freshwater fish in China totaled 439. However, research papers on freshwater fish invasions in China was only 3.7% of the global total, and these researches were mainly on the distribution and biology of invasive fish species, and very few studies included risk assessments. Therefore, we suggest investigating the history, distribution, and mechanisms of invasive species at the national level, evaluating both the positive and negative effects of freshwater fish invasions, and also reinforcing studies of risk assessments in China. 相似文献
11.
Taxonomic distinctness and species richness as measures of functional structure in bird assemblages 总被引:2,自引:0,他引:2
Most traditional "biodiversity" indices have an uncertain ecological interpretation, unfavourable sampling properties, and excessive data requirements. A new index of taxonomic distinctness (the average evolutionary distance between species in an assemblage) has many advantages over traditional measures, but its ecological interpretation remains unclear. We used published behavioural species data in conjunction with bird atlas data to quantify simple functional metrics (the fraction of species engaged in non-competitive interactions, and the average between-species disparity in habitat preferences) for breeding-bird assemblages in Europe and North America. We then analysed correlations of functional metrics with taxonomic distinctness and species richness, respectively. All functional metrics had weak, positive correlations with species richness. In contrast, correlations between functional metrics and taxonomic distinctness ranged from slightly negative to strongly positive, depending on the relative habitat heterogeneity, and on the resource involved in the between-species interaction. Strong positive correlations between taxonomic distinctness and the fraction of interactive species occurred for resources with few producer species per consumer species, and we suggest that taxonomic distinctness is consistently correlated with conservation worth. With its favourable sampling properties and data requirements, this taxonomic distinctness measure is a promising tool for biodiversity research and for environmental monitoring and management. 相似文献
12.
The selection of metrics for ecosystem restoration programs is critical for improving the quality and utility of design and monitoring programs, informing adaptive management actions, and characterizing project success. The metrics selection process, that in practice is left to the subjective judgment of stakeholders, is often complex and should simultaneously take into account monitoring data, environmental models, socio-economic considerations, and stakeholder interests. With limited funding, it is often very difficult to balance the importance of multiple metrics, often competing, intended to measure different environmental, social, and economic aspects of the system. To help restoration planners and practitioners develop the most useful and informative design and monitoring programs, we propose the use of multi-criteria decision analysis (MCDA) methods, broadly defined, to select optimal ecosystem restoration metric sets. In this paper, we apply and compare two MCDA methods, multi-attribute utility theory (MAUT), and probabilistic multi-criteria acceptability analysis (ProMAA), for a hypothetical river restoration case study involving multiple stakeholders with competing interests. Overall, the MCDA results in a systematic, quantitative, and transparent evaluation and comparison of potential metrics that provides planners and practitioners with a clear basis for selecting the optimal set of metrics to evaluate restoration alternatives and to inform restoration design and monitoring. In our case study, the two MCDA methods provide comparable results in terms of selected metrics. However, because ProMAA can consider probability distributions for weights and utility values of metrics for each criterion, it is most likely the best option for projects with highly uncertain data and significant stakeholder involvement. Despite the increase in complexity in the metrics selection process, MCDA improves upon the current, commonly-used ad-hoc decision practice based on consultations with stakeholders by applying and presenting quantitative aggregation of data and judgment, thereby increasing the effectiveness of environmental design and monitoring and the transparency of decision making in restoration projects. 相似文献
13.
As we confront the current environmental crisis, determining the biophysical base (e.g., materials, energy, land, and water) of nations has become paramount. With advanced economies benefiting from the import of resource-intensive primary goods originating from poorer parts of the world, especially emerging nations, these are dilapidating their natural capital. Brazil is one of such emerging economies, whose mining and farming activities, propping up its export-led economic growth, exert great pressure on the environment. In particular, farming has been shown to have one of the world's greatest environmental impacts, especially as a consequence of land use associated with cattle ranching. Since a nation-wide evaluation of land-use types across the whole sectorial spectrum of the country's economy is still lacking, we used the most recently available Input–Output Economic Model for Brazil and the Ecological Footprint method to identify those economic sectors with the greatest potential for appropriating portions of the natural world.Our results show that: (i) the biggest chunk of Brazil's Ecological Footprint is due to its Carbon Footprint and, in particular, emissions from cattle; (ii) only a few economic sectors exhibit high Ecological Footprint values, chiefly those belonging to livestock farming and energy production based on fossil fuels; (iii) excluding the soybeans and slaughter sectors, export-oriented sectors have below-average Ecological Footprint values; and (iv) the percentage of Brazil's Ecological Footprint due to household consumption (excluding imports) is three times bigger than that attributable to exports, with sectors belonging to livestock farming contributing the most to such disparity.These results underscore that the environmental impact of the Brazilian economy can be drastically reduced by tackling the emission-intensive production processes of a few sectors only and disincentivizing the domestic consumption of a narrow range of products, especially with respect to the livestock segment. 相似文献
14.
《Ecological Indicators》2007,7(1):48-70
Two major arguments in favor of using diatoms in water-quality assessments are that their distributions are cosmopolitan and their ecology is well studied. If these assumptions are true, diatom-based monitoring tools could be considered universal and used in any geographic area. Indeed, some diatom metrics based on species indicator values developed in Europe are often used in North America and many other parts of the world. There is considerable evidence, however, that diatom metrics are less useful when applied in a geographic area other than where species relations with environmental characteristics were originally studied to construct the metrics. We used U.S. Geological Survey National Water-Quality Assessment program data to create diatom metrics for monitoring eutrophication, and show here that these metrics provide better assessments in U.S. rivers than similar metrics developed for European inland waters. We also demonstrate that metrics developed by studying diatom–nutrient relationships on the continental-scale can be further refined if combined with regional-scale studies. 相似文献
15.
History matters when individual prior conditions contain important information about the fate of individuals. We present a general framework for demographic models which incorporates the effects of history on population dynamics. The framework incorporates prior condition into the i-state variable and includes an algorithm for constructing the population projection matrix from information on current state dynamics as a function of prior condition. Three biologically motivated classes of prior condition are included: prior stages, linear functions of current and prior stages, and equivalence classes of prior stages. Taking advantage of the matrix formulation of the model, we show how to calculate sensitivity and elasticity of any demographic outcome. Prior condition effects are a source of inter-individual variation in vital rates, i.e., individual heterogeneity. As an example, we construct and analyze a second-order model of Lathyrus vernus, a long-lived herb. We present population growth rate, the stable population distribution, the reproductive value vector, and the elasticity of λ to changes in the second-order transition rates. We quantify the contribution of prior conditions to the total heterogeneity in the stable population of Lathyrus using the entropy of the stable distribution. 相似文献
16.
Studies of various biological tissues have shown that residual strains are important for tissue function. Since a force balance exists in whole wall thickness specimens cut radially, it is evident that layer separation is an important procedure in the understanding of the meaning of residual stresses and strains. The present study investigated the zero-stress state and residual strain distribution in a three-layer model of the pig oesophagus. The middle part of the oesophagus was obtained from six slaughterhouse pigs. Four 3-mm-wide rings were serially cut from each oesophagus. Two of them were used for separating the wall into mucosa-submucosa, inner and outer muscle layers. The remaining two rings were kept as intact rings. The inner and outer circumferences and wall thickness of different layers in intact and separated rings were measured from the digital images in the no-load state and zero-stress state. The opening angle was measured and the residual strain at the inner and outer surface of different layers and the intact wall were computed. Compared with intact sectors (62.8+/-9.8 degrees ), the opening angles were smaller in the inner muscle sectors (37.2+/-11.4 degrees , P<0.01), whereas the opening angles of mucosa-submucosa (63.9+/-6.8 degrees ) and outer muscle sectors (63.9+/-6.8 degrees ) did not differ (P>0.1). Referenced to the zero-stress state of the intact sectors, the inner and outer residual strains of the intact rings was -0.128+/-0.043 and outer residual strain was 0.308+/-0.032. Referenced to the "true" zero-stress state of separated three-layered sectors, the inner residual strain of intact rings were -0.223+/-0.021 (P<0.01) and 0.071+/-0.022 (P<0.01). Referenced to the "true" zero-stress state, the residual strain distribution of different layers in intact rings was shown that the inner surface residual strain was negative at mucosa-submucosa and inner muscle layers and was positive at outer muscle layer, whereas the outer surface residual strain was negative at the mucosa-submucosa layer and positive at the inner and outer muscle layers. For the separated different layered rings, the inner residual strain was negative and outer residual strain was positive; however, the absolute values did not differ (P>0.1). In conclusion, it is possible to microsurgically separate the oesophagus into three layers, i.e., mucosa-submucosa, inner muscle and outer muscle layers, the residual strain differ between the layers, and the residual strain distribution was more uniform after the layers were separated. 相似文献
17.
Martin R. Tillotson Junguo Liu Dabo Guan Pute Wu Xu Zhao Guoping Zhang Stephan Pfister Markus Pahlow 《The International Journal of Life Cycle Assessment》2014,19(8):1561-1565
Recognizing the need for a comprehensive review of the tools and metrics for the quantification and assessment of water footprints, and allowing for the opportunity for open discussion on the challenges and future of water footprinting methodology, an international symposium on water footprint was organized. The Water Footprint Symposium was held in December 2013 at the University of Leeds, UK. In particular, four areas were highlighted for discussion: water footprint and agriculture, quantification of water footprint, industrial water footprint, and from theory to practice. Discussion was organized to focus on the “prioritization of water footprint research & applications to practical sectors”. The concept of water footprinting has helped to better communicate water management and assessment among different research and user communities. Significant research progress has been made in the relations between water footprint and agriculture, quantification of water footprint, industrial water footprint, and the transition from theory to practice. Future water footprint research needs to further enhance assessment accuracy, improve sustainability assessment methodology, develop databases, address uncertainties, and prioritize application by government and in practical sectors. More information on the symposium can be found on the water@leeds website: http://www.wateratleeds.org/conferences/2013/water-footprint-symposium. 相似文献
18.
We developed a model of a national economy in which the phenomena of supply, demand, economic growth, and international trade are represented in terms of energy flows. In examining the structure of the economy, we distinguish between the energy embodied in capital assets used in the production and distribution of energy and that embodied in capital assets and goods that consume energy. Sources used to quantify the energy flows include: end‐use energy data by economic sector; International Energy Agency–style national energy balances, and national input‐output tables. As an example, the Canadian economy for 2008 produced 16.97 exajoules (EJ) of energy, which after net export of 6.16 EJ and other adjustments left a total primary energy consumption of 10.61 EJ. The energy supply and distribution sectors used close to 32% (3.36 EJ) of total primary consumption. Analysis of primary energy consumption shows that 25.14% was embodied in household consumption, 22.85% was consumed directly by households, 7.88% was embodied in government services, and 34.07% was embodied in exports. Of significance to economic growth, 7.14% was embodied in capital in energy demanding sectors, 1.25% in energy consuming personal assets, and 1.52% in supply sector capital. The energy return on energy investment was relatively constant, averaging 5.14 between 1990 and 2008. Capital investments required to decouple the Canadian economy from its dependence on fossil fuels are discerned. 相似文献
19.
K N Dudkin I V Chueva Ia A Bedrov E A Vershinina 《Zhurnal vysshe? nervno? deiatelnosti imeni I P Pavlova》1984,34(4):649-656
The use of entropy of choices distribution in studying the processes of learning and long-term memory in rhesus monkeys during differentiation of periodic and non-periodic visual stimuli, showed that the transition from the unlearned state to the learned one proceeds not gradually but in two stages; the first stage--the accumulation of information and externally random behaviour, the second stage--rapid transition to the learned behaviour. For "filters" selective to spatial frequency, the change of stimuli orientation leads to an increase of the behaviour entropy. For "filters" selective to the bar width, the entropy practically does not change. During prolonged storage of acquired information, in the long-term memory, its partial loss takes place leading to an increase of the behaviour entropy. The difference between the entropy determined directly after the learning and that determined again after a prolonged storage of the memorized habit characterizes the quantity of information lost during the storage period. 相似文献
20.
Edith Calixto-Pérez Jesús Alarcón-Guerrero Gabriel Ramos-Fernández Pedro Américo D. Dias Ariadna Rangel-Negrín Monica Améndola-Pimenta Cristina Domingo Víctor Arroyo-Rodríguez Gilberto Pozo-Montuy Braulio Pinacho-Guendulain Tania Urquiza-Haas Patricia Koleff Enrique Martínez-Meyer 《Primates; journal of primatology》2018,59(5):451-467
Ecological niche modeling is used to estimate species distributions based on occurrence records and environmental variables, but it seldom includes explicit biotic or historical factors that are important in determining the distribution of species. Expert knowledge can provide additional valuable information regarding ecological or historical attributes of species, but the influence of integrating this information in the modeling process has been poorly explored. Here, we integrated expert knowledge in different stages of the niche modeling process to improve the representation of the actual geographic distributions of Mexican primates (Ateles geoffroyi, Alouatta pigra, and A. palliata mexicana). We designed an elicitation process to acquire information from experts and such information was integrated by an iterative process that consisted of reviews of input data by experts, production of ecological niche models (ENMs), and evaluation of model outputs to provide feedback. We built ENMs using the maximum entropy algorithm along with a dataset of occurrence records gathered from a public source and records provided by the experts. Models without expert knowledge were also built for comparison, and both models, with and without expert knowledge, were evaluated using four validation metrics that provide a measure of accuracy for presence-absence predictions (specificity, sensitivity, kappa, true skill statistic). Integrating expert knowledge to build ENMs produced better results for potential distributions than models without expert knowledge, but a much greater improvement in the transition from potential to realized geographic distributions by reducing overprediction, resulting in better representations of the actual geographic distributions of species. Furthermore, with the combination of niche models and expert knowledge we were able to identify an area of sympatry between A. palliata mexicana and A. pigra. We argue that the inclusion of expert knowledge at different stages in the construction of niche models in an explicit and systematic fashion is a recommended practice as it produces overall positive results for representing realized species distributions. 相似文献