中国征收碳税应对碳关税的经济分析——以美国为例

碳税和碳关税作为一种价格调整机制,长期而言会对经济系统中各主体产生较强的约束力。通过GTAP-E模型的模拟分析,得出以下结论:在目前的发展阶段,碳关税并非有效的低碳经济发展政策,尤其是美国对中国征收碳关税对降低世界碳排放量的影响有限;美国针对中国采取的碳关税政策将在一定程度上对我国出口贸易产生负向影响,尤其是对中国的高碳产业影响较大;当中美采取相同的碳税政策时,碳税的征收对中国GDP造成较大的负面影响,且中国自主采取节能减排方案不足以应对美国碳关税的负面效应;而当两者采取差异化政策时,中国主动采取节能减排行动可以有效应对美国碳关税的威胁。     

重工业城市(抚顺)实施清洁生产发展循环经济实例研究

论证了清洁生产与循环经济之间的关系 ,全面论述了发展循环经济的重要性、必要性及现实意义 ,提出了发展循环经济的切实可行的对策方案 ,为开创资源型城市可持续发展道路打下了扎实的理论基础。同时 ,以抚顺为研究对象 ,通过对其工业布局、产业结构、经济发展规模的分析 ,探索找出了重工业城市实施清洁生产的最佳途径。     

Decomposition of Emission Multipliers in a National Accounting Matrix Including Environmental Accounts

This study defines a linear model of emission multipliers through the use of a national accounting matrix including environmental accounts (NAMEA) for the Catalan economy that integrates the regional economic information with the greenhouse gas emissions. As in the model of income multipliers, emission multipliers can be divided into own effects, open effects, and circular effects. This decomposition shows the channels of income generation and their effects on regional greenhouse gas emissions. Our results reveal significant differences among the three gases analyzed as well as important asymmetries at a sectorial level.     

Iron deficiency leads to repression of a non-canonical methionine salvage pathway in Schizosaccharomyces pombe

The methionine salvage pathway (MSP) regenerates methionine from 5′-methylthioadenosine (MTA). Aerobic MSP consists of six enzymatic steps. The mug14⁺ and adi1⁺ genes that are involved in the third and fifth steps of the pathway are repressed when Schizosaccharomyces pombe undergoes a transition from high- to low-iron conditions. Results consistently show that methionine auxotrophic cells (met6Δ) require iron for growth in the presence of MTA as the sole source of methionine. Inactivation of the iron-using protein Adi1 leads to defects in the utilization of MTA. In the case of the third step of the pathway, co-expression of two distinct proteins, Mta3 and Mde1, is required. These proteins are interdependent to rescue MTA-dependent growth deficit of met6Δ cells. Coimmunoprecipitation experiments showed that Mta3 is a binding partner of Mde1. Meiotic met6Δ cells co-expressing mta3⁺ and mde1⁺ or mta3⁺ and mug14⁺ produce comparable levels of spores in the presence of MTA, revealing that Mde1 and Mug14 share a common function when co-expressed with Mta3 in sporulating cells. In sum, our findings unveil several novel features of MSP, especially with respect to its regulation by iron and the discovery of a non-canonical third enzymatic step in the fission yeast.     

Energy cost and running mechanics during a treadmill run to voluntary exhaustion in humans

The aim of the present study was to examine the physiological and mechanical factors which may be concerned in the increase in energy cost during running in a fatigued state. A group of 15 trained triathletes ran on a treadmill at velocities corresponding to their personal records over 3000m [mean 4.53 (SD 0.28) m · s⁻¹] until they felt exhausted. The energy cost of running (C _R) was quantified from the net O₂ uptake and the elevation of blood lactate concentration. Gas exchange was measured over 1 min firstly during the 3rd–4th min and secondly during the last minute of the run. Blood samples were collected before and after the completion of the run. Mechanical changes of the centre of mass were quantified using a kinematic arm. A significant mean increase [6.9 (SD 3.5)%, P < 0.001] in C _R from a mean of 4.4 (SD 0.4) J · kg⁻¹ · m⁻¹ to a mean of 4.7 (SD 0.4) J · kg⁻¹ · m⁻¹ was observed. The increase in the O₂ demand of the respiratory muscles estimated from the increase in ventilation accounted for a considerable proportion [mean 25.2 (SD 10.4)%] of the increase in C_R. A mean increase [17.0 (SD 26.0)%, P < 0.05] in the mechanical cost (C _M) from a mean of 2.36 (SD 0.23) J · kg⁻¹ · m⁻¹ to a mean of 2.74 (SD 0.55) J · kg⁻¹ · m⁻¹ was also noted. A significant correlation was found between C _R and C _M in the non-fatigued state (r = 0.68, P < 0.01), but not in the fatigued state (r = 0.25, NS). Furthermore, no correlations were found between the changes (from non-fatigued to fatigued state) in C _R and the changes in C _M suggesting that the increase in C _R is not solely dependent on the external work done per unit of distance. Since step frequency decreased slightly in the fatigued state, the internal work would have tended to decrease slightly which would not be compatible with an increase in C _R. A stepwise regressions showed that the changes in C _R were linked (r = 0.77, P < 0.01) to the changes in the variability of step frequency and in the variability of potential cost suggesting that a large proportion of the increase in C _R was due to an increase in the step variability. The underlying mechanisms of the relationship between C _R and step variability remains unclear. Accepted: 15 September 1997     

The distribution of epiphyte growth-forms in the canopy of a Colombian cloud-forest

Cloud forests are known for their abundance in epiphytes. The growth-form composition of the epiphytic vegetation in the crowns of two tree-species in an upper-andean forest in Colombia is described. Bryophytes formed the bulk of the living epiphytic biomass, with tall turfs and smooth mats (sensu Richards 1984) as commonest growth-forms. Vascular plants and lichens were subordinate to bryophytes. Along the canopy-branches a clear sequence of growth-forms could be demonstrated. Analysis of this gradient by Detrended Correspondence Analysis (DCA), Two Way Indicator Species Analysis (TWINSPAN) and calculation of association-indices between growth-forms revealed two basic groups. One group is typical for the inner canopy, another for the outer canopy. An important determinant of the growth-form composition was the phorophyte species. The vegetational gradient was interpreted in terms of gradual changes in microclimatological factors, water- and nutrient availability and substratumage.     

Methodology and Indicators of Economy‐wide Material Flow Accounting

This contribution presents the state of the art of economy‐wide material flow accounting. Starting from a brief recollection of the intellectual and policy history of this approach, we outline system definition, key methodological assumptions, and derived indicators. The next section makes an effort to establish data reliability and uncertainty for a number of existing multinational (European and global) material flow accounting (MFA) data compilations and discusses sources of inconsistencies and variations for some indicators and trends. The results show that the methodology has reached a certain maturity: Coefficients of variation between databases lie in the range of 10% to 20%, and correlations between databases across countries amount to an average R² of 0.95. After discussing some of the research frontiers for further methodological development, we conclude that the material flow accounting framework and the data generated have reached a maturity that warrants material flow indicators to complement traditional economic and demographic information in providing a sound basis for discussing national and international policies for sustainable resource use.     

Statistical entropy analysis to evaluate resource efficiency: Phosphorus use in Austria

In a resource efficient economy, entropy generation must be kept low and high-entropy wastes should be transformed into low-entropy recycled products, thus saving natural resources. Based on this idea, statistical entropy analysis (SEA) was put forward as a method to evaluate material flow systems with respect to their ability to concentrate or dilute a substance throughout its life cycle using a single metric, relative statistical entropy (RSE). Whereas its application has so far been restricted to highly aggregated material flow systems or to assessments at plant or process level, in the present study the SEA method was adapted to assess the efficiency of resource use in material flow systems which consist of numerous resource flows and include multiple recycling loops. Phosphorus (P) use in Austria served as a case study to illustrate SEA-based resource efficiency assessment for different scenarios and over time. The evaluation enabled exploiting the outcomes of existing P flow studies in a straightforward way and produced additional insights related to the characteristics of resource use within the system. Changes in P management over time had a significant effect on the resource efficiency of P use. The RSE increased by 40% due to P use in Austria in the year 2000 compared to an increase of 30% in 2010. The generally favorable trend of statistical entropy (lower dissipation) in 2010 could be attributed mainly to lower dissipative emissions, more efficient bio-industry, and increasing P removal rates in waste water treatment, which overcompensated the negative impact of the ban of recycling of meat and bone meal (in 2001) on P use efficiency. Further, the SEA-based assessment applied to a scenario of optimized P management reflected the positive effects of measures to reduce emissions, enhance recycling, and reduce consumption of P on resource efficiency (50% lower RSE increase in the target system compared to the original state). In synthesis, this study shows that the SEA method is able to integrate various dimensions of resource use into a single indicator, which can serve as a basis to assess and improve the resource efficiency of macro-scale material flow systems.     

一类灰色项时间序列模型及其应用

利用灰色系统理论与时间序列分析,提出了带灰色项的时间序列模型,对这类模型进行了分析,给出了建模与预报方法,并将其应用于我国农业产值问题的预报与研究之中,模型的正确性得到了检验．