首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 78 毫秒
1.
Eco-efficiency is a useful guide to dairy farm sustainability analysis aimed at increasing output (physical or value added) and minimizing environmental impacts (EIs). Widely used partial eco-efficiency ratios (EIs per some functional unit, e.g. kg milk) can be problematic because (i) substitution possibilities between EIs are ignored, (ii) multiple ratios can complicate decision making and (iii) EIs are not usually associated with just the functional unit in the ratio’s denominator. The objective of this study was to demonstrate a ‘global’ eco-efficiency modelling framework dealing with issues (i) to (iii) by combining Life Cycle Analysis (LCA) data and the multiple-input, multiple-output production efficiency method Data Envelopment Analysis (DEA). With DEA each dairy farm’s outputs and LCA-derived EIs are aggregated into a single, relative, bounded, dimensionless eco-efficiency score, thus overcoming issues (i) to (iii). A novelty of this study is that a model providing a number of additional desirable properties was employed, known as the Range Adjusted Measure (RAM) of inefficiency. These properties altogether make RAM advantageous over other DEA models and are as follows. First, RAM is able to simultaneously minimize EIs and maximize outputs. Second, it indicates which EIs and/or outputs contribute the most to a farm’s eco-inefficiency. Third it can be used to rank farms in terms of eco-efficiency scores. Thus, non-parametric rank tests can be employed to test for significant differences in terms of eco-efficiency score ranks between different farm groups. An additional DEA methodology was employed to ‘correct’ the farms’ eco-efficiency scores for inefficiencies attributed to managerial factors. By removing managerial inefficiencies it was possible to detect differences in eco-efficiency between farms solely attributed to uncontrollable factors such as region. Such analysis is lacking in previous dairy studies combining LCA with DEA. RAM and the ‘corrective’ methodology were demonstrated with LCA data from French specialized dairy farms grouped by region (West France, Continental France) and feeding strategy (regardless of region). Mean eco-efficiency score ranks were significantly higher for farms with <10% and 10% to 30% maize than farms with >30% maize in the total forage area before correcting for managerial inefficiencies. Mean eco-efficiency score ranks were higher for West than Continental farms, but significantly higher only after correcting for managerial inefficiencies. These results helped identify the eco-efficiency potential of each region and feeding strategy and could therefore aid advisors and policy makers at farm or region/sector level. The proposed framework helped better measure and understand (dairy) farm eco-efficiency, both within and between different farm groups.  相似文献   

2.
3.
An Internet-based environmentally conscious decision support tool (EcoDS) has been developed for life-cycle management EcoDS involves an initial vertical streamlining step, where the significant life-cycle stages, stressors, and impact categories are selected and cross-correlated. Because the streamlining is performed prior to the inventory, the approach expedites data collection. Comparisons among alternative product designs or manufacturing processes are based on two metrics: financial risk (or cost) and "residual" risk. For purposes of evaluation these two indicators are individually aggregated using a user or organization-specified value system. A salient feature of EcoDS is that this output can be condensed into a single summary matrix akin to a hybrid pro forma income statement and environmental balance sheet. The clear delineation between the tradeoffs involved in each alternative facilitates decision making by upper management. A case study on painting attematives is presented to illustrate the methodology  相似文献   

4.
Ecological problems — because they involve interactions and interfaces — require for their solution a flexible, interdisciplinary approach. Ecological research can best be supported in an international, intergovernmental framework, but, at first sight, the requirements of such a framework may seem unwieldy to traditionally trained natural and social scientists. Experience acquired in implementing UNESCO's Man and the Biosphere (MAB) Programme indicates that it is possible to overcome the difficulties of conducting integrated research and to achieve internationally comparable results. The MAB Programme is a good example of both the potential and the limitations of integrated, international ecological research programs. There seem to be three imperatives for success: (1) research must be problem oriented, (2) the. unit selected for study must be sufficiently comprehensive and based on human use systems, and (3) research workers in various natural and social science disciplines and the administrative decision-makers must share responsibility for planning and execution.  相似文献   

5.
Abstract. We assessed survival and growth of transplanted saplings of understory broad‐leaved trees (Oreopanax xalapensis, Rapaneajuergensenii, Rhamnus sharpii and Tern‐stroemia lineata) and canopy conifers (Abies guatemalensis, Pinus ayacahuite and P. pseudostrobus) into Grassland (GR), Mid‐Successional Oak Forest (MS), and Old‐Growth Oak Forest (OF) stands in the central highlands of Chiapas, Mexico. A total of 727 plants were monitored over eight years. The results suggest habitat preferences of the studied species that should be considered for their conservation oriented management. Conifers had highest survival and growth in GR, while broad‐leaved trees survived better under sparse canopy in MS, but grew tallest in full light. Saplings of all species in dense canopy sites in OF were smaller, and the survival of conifers was lower. An integrated response index (IRI) calculated for each species with survival and relative growth rates showed similar trends. Re‐introduction of the endangered A. guatemalensis is possible in open habitats if fire, trampling and grazing are suppressed. Open habitats in current man‐made landscapes in the highlands of Chiapas may limit the establishment of understory trees requiring partial shade. Inclusion of such species in restoration programs has not been usual so far; yet, local and global interest in native species for such programs is increasing. Information on the response of these kind of species in contrasting habitats may help to incorporate them in the management of high‐diversity forests that may follow pine plantations.  相似文献   

6.

????? 阐述了医院信息系统的应用主线和系统当前面临的挑战,探讨了运用数据整合、统一平台以及面向服务的技术架构等方法,完成多元化信息集成交换平台的解决方案,对数据进行集成与利用,从而达到系统间的数据共享与交换、支持管理决策与分析的目的。

  相似文献   

7.
Fixed, genetically determined, mate preferences for species whose adult phenotype varies with rearing environment may be maladaptive, as the phenotype that is most fit in the parental environment may be absent in the offspring environment. Mate preference in species with polyphenisms (environmentally dependent alternative phenotypes) should therefore either not focus on polyphenic traits, be polyphenic themselves, or learned each generation. Here, we test these alternative hypotheses by first describing a female‐limited seasonal polyphenism in a sexually dimorphic trait in the butterfly Bicyclus anynana, dorsal hindwing spot number (DHSN), and then testing whether male and female mate preferences for this trait exist, and whether they are seasonally polyphenic, or learned. Neither naïve males nor naïve females in either seasonal form exhibited mating preferences for DHSN. However, males, but not females, noticed DHSN variation and learned mate preferences for DHSN. These results suggest that individuals may accommodate environmentally dependent variation in morphological traits via learned mate preferences in each generation, and that learned mate preference plasticity can be sexually dimorphic.  相似文献   

8.
The extracellular matrix (ECM) offers a structural basis for regulating cell functions while also acting as a collection point for bioactive molecules and connective tissue cells. To perform pathological functions under a pathological condition, the involved cells need to regulate the ECM to support their altered functions. This is particularly common in the development of cancer. The ECM has been recognized as a key driver of cancer development and progression, and ECM remodeling occurs at all stages of cancer progression. Thus, cancer cells need to change the ECM to support relevant cell surface adhesion receptor–mediated cell functions. In this context, it is interesting to examine how cancer cells regulate ECM remodeling, which is critical to tumor malignancy and metastatic progression. Here, we review how the cell surface adhesion receptor, syndecan, regulates ECM remodeling as cancer progresses, and explore how this can help us better understand ECM remodeling under these pathological conditions  相似文献   

9.
Coating of solid dosage forms is an important unit operation in the pharmaceutical industry. In recent years, numerical simulations of drug manufacturing processes have been gaining interest as process analytical technology tools. The discrete element method (DEM) in particular is suitable to model tablet-coating processes. For the development of accurate simulations, information on the material properties of the tablets is required. In this study, the mechanical parameters Young’s modulus, coefficient of restitution (CoR), and coefficients of friction (CoF) of gastrointestinal therapeutic systems (GITS) and of active-coated GITS were measured experimentally. The dynamic angle of repose of these tablets in a drum coater was investigated to revise the CoF. The resulting values were used as input data in DEM simulations to compare simulation and experiment. A mean value of Young’s modulus of 31.9 MPa was determined by the uniaxial compression test. The CoR was found to be 0.78. For both tablet–steel and tablet–tablet friction, active-coated GITS showed a higher CoF compared with GITS. According to the values of the dynamic angle of repose, the CoF was adjusted to obtain consistent tablet motion in the simulation and in the experiment. On the basis of this experimental characterization, mechanical parameters are integrated into DEM simulation programs to perform numerical analysis of coating processes.  相似文献   

10.
The purpose of this paper is to explore CO2 emission efficiency in china’s agricultural sector during the period 2001–2012. We also analyze the CO2 emission reduction potential as well as its two main contributors (i.e. technology gap inefficiency and managerial failure). The meta-frontier framework is adopted to reflect technology heterogeneities in China’s agricultural sector among the eastern, central and western regions. Based on the DEA (data envelopment analysis) method, the models are estimated by means of linear programming. Empirical results indicate that CO2 emission efficiency of the agricultural sector in western China is the lowest compared with eastern and central China; stemming from the fact that most provinces in western China generally fall behind in terms of technology. The total potential agricultural CO2 emissions reduction is estimated at 1161.33 million tons, which can be attributed to managerial failure in the case of eastern and central China. For western China, it can be attributed to both technological gap inefficiency and managerial failure.  相似文献   

11.
As a follow-up to the recent interest in simple additive models for diversity partitioning, we have used the analogy with ANOVA models to propose a consistent framework that allows both (i) apportioning the amount of regional diversity into environmentally and/or geographically-related components (ii) detecting individual species' habitat preferences using permutation tests. We addressed geographical aspects by relating diversity partition to dissimilarity measurements. An illustration based on an inventory of trees in a tropical rain forest of French Guiana is provided.  相似文献   

12.
Through radical redesign of business processes and systems, policies, and organizational structures, the business process reengineering (BPR) effort was initiated in the manufacturing industry to seek performance breakthroughs. This paper describes a novel approach to the BPR, which applies flexible manufacturing systems (FMSs) design and analysis technologies, such as simulation, multicriteria decision support, and artificial intelligence (AI). These technologies are integrated to design and analyze specific FMS models related to the proposed technical and managerial changes in an industrial case. First, the literature is reviewed to obtain an understanding of the BPR concept and the role of FMS design and analysis in BPR. Second, a decision-making support system is developed to illustrate how the FMS design and analysis would affect BPR. Finally, a summary of the integrated approach practice in industry and conclusions are presented. The paper shows that the key to a successful BPR approach is the identification and analysis of specific proposed models. It also demonstrates that the integrated approach enables engineers to improve the efficiency of BPR.  相似文献   

13.
The task of process modeling in a manufacturing environment centers around controlling and improving the flow of materials. This flow comprises a complicated web of control and physical systems. Despite a variety of manufacturing system modeling approaches, more rigorous process modeling is required. This paper presents an integrated modeling framework for manufacturing systems (IMF-M). Conceptual modeling of physical materials flow supported by a graphical representation facilitates improvement of operations in manufacturing environments. A declarative and executable representation of control information systems helps to improve information management by managing a variety of information models with improved readability and reusability. A unified representation of the physical process and information system provides a common modeling milieu in which efforts can be coordinated among several groups working in the different domains of scheduling, shop floor and logistics control, and information system. Since the framework helps adapt to the changes of the physical process and information system affecting each other in a consistent manner, the modeling output enhances integration of the manufacturing system.  相似文献   

14.
By most accounts, the mind arises from the integrated activity of large populations of neurons distributed across multiple brain regions. A contrasting model is presented in the present paper that places the mind/brain interface not at the whole brain level but at the level of single neurons. Specifically, it is proposed that each neuron in the nervous system is independently conscious, with conscious content corresponding to the spatial pattern of a portion of that neuron's dendritic electrical activity. For most neurons, such as those in the hypothalamus or posterior sensory cortices, the conscious activity would be assumed to be simple and unable to directly affect the organism's macroscopic conscious behavior. For a subpopulation of layer 5 pyramidal neurons in the lateral prefrontal cortices, however, an arrangement is proposed to be present such that, at any given moment: (i) the spatial pattern of electrical activity in a portion of the dendritic tree of each neuron in the subpopulation individually manifests a complexity and diversity sufficient to account for the complexity and diversity of conscious experience; (ii) the dendritic trees of the neurons in the subpopulation all contain similar spatial electrical patterns; (iii) the spatial electrical pattern in the dendritic tree of each neuron interacts non-linearly with the remaining ambient dendritic electrical activity to determine the neuron's overall axonal response; (iv) the dendritic spatial pattern is reexpressed at the population level by the spatial pattern exhibited by a synchronously firing subgroup of the conscious neurons, thereby providing a mechanism by which conscious activity at the neuronal level can influence overall behavior. The resulting scheme is one in which conscious behavior appears to be the product of a single macroscopic mind, but is actually the integrated output of a chorus of minds, each associated with a different neuron.  相似文献   

15.
The electric power industry plays a critical role in the economy and the environment, and it is important to examine the economic, environmental, and policy implications of current and future power generation scenarios. However, the tools that exist to perform the life cycle assessments are either too complex or too aggregated to be useful for these types of activities. In this work, we build upon the framework of existing input‐output (I‐O) models by adding data about the electric power industry and disaggregating this single sector into additional sectors, each representing a specific portion of electric power industry operations. For each of these disaggregated sectors, we create a process‐specific supply chain and a set of emission factors that allow calculation of the environmental effects of that sector's output. This new model allows a much better fit for scenarios requiring more specificity than is possible with the current I‐O model.  相似文献   

16.
Globally, agriculture is a dominant form of human use of land with agro-ecosystems covering about 40% of the terrestrial surface of the Earth. In this context, the European Union considers agriculture a key sector of the economy, recognizing, however, the related environmental implications. The aim of this paper is to examine the agricultural efficiency of EU countries, through a bootstrap-Data Envelopment Analysis (DEA) approach, an effective nonparametric method for evaluating the relative efficiency of the decision-making units. European datasets, suitable for policies and focused on the integration between agricultural productivity and ecosystem services (ESs) conservation, have been used to support planners and managers. Data related to five inputs (labor, land, capital, fertilizers, and irrigation area) and to one output connected to the economic value of agricultural production were collected from 1993 to 2013. The results show that the majority of EU countries have been experiencing increasing or decreasing returns to scale, highlighting their potential to increase their production efficiency by modifying their input use. Both for the output-oriented approach and the input-oriented approach, the majority of EU countries could better rationalize their input use obtaining more outputs and achieving production efficiency. DEA, a non-parametric methodology has been applied, using the concept of a reference group of efficient decision-making units that produce a similar output (peer group). Input-oriented and output-oriented DEA results and comparison indicate that most of the oldest EU countries have a more efficient and optimized crop production process in terms of resource savings and output maximization. This is probably due to the application of the Common Agricultural Policy. Therefore, in policy planning but also in management decisions, attention should always be paid not only to the maximization of agricultural production, but also to the environmental resource overexploitation. In this sense, best agricultural practices could represent a model to follow because they can maintain ESs without depressing production by using practices like conservation tillage, crop diversification, legume intensification and biological control perform giving the same results as intensive, high-input systems.  相似文献   

17.
《Biotechnology advances》2017,35(2):240-250
Engineering a functional tissue ex vivo requires a synchronized effort towards developing technologies for ECM mimicking scaffold and cultivating tissue-specific cells in an integrated and controlled manner. Cell-interactive scaffolds in three dimensions (3D), designed and processed appropriately with an apt biomaterial to yield optimal porosity and mechanical strength is the key in tissue engineering (TE). In order to accomplish these facets in a 3D scaffold, multiple techniques and processes have been explored by researchers all over the world. New techniques offering reasonable flexibility to use blends of different materials for integrated tissue-specific mechanical strength and biocompatibility have an edge over conventional methods. They may allow a combinatorial approach with a mix of materials while incorporating multiple processing techniques for successful creation of tissue-specific ECM mimics. In this review, we analyze the material requirement from different TE perspectives, while discussing pros and cons of advanced fabrication techniques for scale-up manufacturing.  相似文献   

18.
Increasingly, organizations are working to reduce the environmental footprint of their supply chains. The use of environmentally preferable purchasing criteria is one strategy organizations use to address this goal. However, evaluating the environmental performance of these criteria (e.g., recycled content, biodegradable, renewable, and so on) has remained elusive. Life cycle assessment (LCA) can measure the impact reduction potential of sourcing strategies. However, full process‐based LCAs are time‐consuming and costly across multiple criteria of thousands of products and inputs purchased in an organizational setting. A streamlined “hotspot” methodology is presented using a combination of environmentally extended economic input‐output (EEIO) approaches and extant literature to identify hotspots in which to constrain a parameterized process‐based LCA. A case study of breakfast cereal manufacturing is developed to (1) assess the efficiencies associated with the hotspotting approach and (2) demonstrate its applicability in generating comparable decision signals of environmentally preferable sourcing criteria for procurement and supply‐chain managers along the dimensions of global warming potential and water use.  相似文献   

19.
This article introduces a multiagent simulation framework for investigating the emergence of niche markets for environmentally innovative products. It clarifies how consumer preferences, business strategy, and government policy interact during market development. The framework allows investigation of the effects of uncertainty and agents' corresponding coping strategies. We describe the model, illustrate how it works when applied to the case of hybrid cars, and analyze results spanning several policy cases and a range of scenarios that make different assumptions about the heterogeneity of agents. Heterogeneity within each agent class strongly influences aggregate outcomes. Innovative firms can create green products in response to or in anticipation of government regulation, but true green niche markets do not emerge unless there are also green consumers. Niche markets do not go mainstream unless scale economies drive costs down to parity with conventional products. Preferred environmental innovation policies change with heterogeneity assumptions.  相似文献   

20.
? The ectomycorrhizal (ECM) symbiosis was historically considered restricted to the temperate zones, but recent studies have shown the importance of this symbiosis across the tropics. We examined ECM fungal diversity, host plant phylogeny and ECM host preferences in a rainforest dominated by the leguminous host plants Dicymbe corymbosa, Dicymbe altsonii and Aldina insignis. ? Ectomycorrhizal fungi were identified by internal transcribed spacer rDNA sequencing and host species were verified with chloroplast trnL sequencing. To test whether Dicymbe and Aldina represent independent gains of the ECM symbiosis, we constructed a Fabaceae phylogeny using MatK and trnL. We identified four independent ECM lineages within the Fabaceae. ? We detected a diverse community of 118 ECM species dominated by the /clavulina, /russula-lactarius, /boletus, and /tomentella-thelephora lineages. Ectomycorrhizal species in Agaricales, Atheliales and Polyporales may represent previously unrecognized tropical-endemic ECM lineages. Previous studies suggested that ECM fungi did not diversify in the tropics, but the /clavulina lineage appears to have a center of diversity in tropical South America. ? Dicymbe and Aldina represent independent gains of the ECM symbiosis in Fabaceae but their fungal symbionts showed no host preferences. Spatial factors are more important than hosts in structuring the ECM fungal community in this ecosystem.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号