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Vegetation cover and production were evaluated after nearly 7 years of livestock grazing exclusion and shrub control in an area with a long history of heavy livestock grazing in the southern Chihuahuan Desert, Mexico. An exclosure was established to prevent livestock grazing. In half of the excluded area, the main shrub, Larrea tridentata , was mechanically controlled. Outside the exclosure, heavy livestock grazing occurred as customary and shrubs were not controlled. Absence of grazing resulted in 50% higher grass cover and 35% higher total biomass. Larrea tridentata cover was twice as high on the grazed area as on the ungrazed area. Vegetation cover was dominated by grasses (42%) in the ungrazed area, whereas in the grazed area, cover was equally divided between grasses (28%) and shrubs (27%). Shrub control did not affect vegetation cover or herbage production. Multivariate analysis confirmed that inside the excluded area, shrub control had little impact on the plant community. The effect of grazing, however, clearly distinguished the community outside the exclosure from that inside the exclosure.  相似文献   
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A renewed concern with Aristotle’s thought about the economic aspects of human life and society can be observed. Aristotle dealt with the economic issues in his practical philosophy. He thus considered ‘the economic’ within an ethical and political frame. This vision is coherent with a specific ontology of ‘the economic’ according to Aristotle. In a recent paper, I analysed this ontology and left its consequences, especially for Ethics and Politics, for another paper. In this article, I firstly summarise the reasoning and conclusions of the aforementioned paper. Then, I extract the ethical and political “lessons” of the Aristotelian conception. I finally add a section with epistemological “lessons”, and consequences for the teaching of Economics.  相似文献   
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The vast majority of Mesozoic and early Cenozoic metatherian mammals (extinct relatives of modern marsupials) are known only from partial jaws or isolated teeth, which give insight into their probable diets and phylogenetic relationships but little else. The few skulls known are generally crushed, incomplete or both, and associated postcranial material is extremely rare. Here we report the discovery of an exceptionally large number of almost undistorted, nearly complete skulls and skeletons of a stem-metatherian, Pucadelphys andinus, in the early Palaeocene epoch of Tiupampa in Bolivia. These give an unprecedented glimpse into early metatherian morphology, evolutionary relationships and, especially, ecology. The remains of 35 individuals have been collected, with 22 of these represented by nearly complete skulls and associated postcrania. These individuals were probably buried in a single catastrophic event, and so almost certainly belong to the same population. The preservation of multiple adult, sub-adult and juvenile individuals in close proximity (<1?m(2)) is indicative of gregarious social behaviour or at least a high degree of social tolerance and frequent interaction. Such behaviour is unknown in living didelphids, which are highly solitary and have been regarded, perhaps wrongly, as the most generalized living marsupials. The Tiupampan P.?andinus population also exhibits strong sexual dimorphism, which, in combination with gregariousness, suggests strong male-male competition and polygyny. Our study shows that social interactions occurred in metatherians as early as the basal Palaeocene and that solitary behaviour may not be plesiomorphic for Metatheria as a whole.  相似文献   
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The aim of this paper is to apply a systemic methodology to analyse the concept of info-inclusion which can guide strategic actions of institutions within civil society and within several levels of government. The paper provides a plan of action that, integrated with other tools, aims at fighting the technological and social gap. We apply Soft System Methodology (SSM), because it provides a holistic approach to info-exclusion. SSM is often used to analyse and resolve problems in complex social studies such as info-exclusion. An info-exclusion reduction project, developed by a university in the country region of Sao Paulo will be provided as a case study. This project is one of the several Brazilian initiatives to solve the problem of limited access to information technology tools. We start by contextualising info-exclusion in Brazil and follow with a review of SSM. We then introduce the concept of info-inclusion and apply SSM to it. We end with a discussion of the results obtained and with some suggestions for action and possible improvements.  相似文献   
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Competency-based management is a strategic approach for Human Resources Management and organizational change. Additionally, in business environment, information technologies competencies are a significant factor to organizational success (Bharadwaj, MIS Q 24(1):169–196, 2006). However the implementation of a model of competency-based management in business environment is difficult and complex (Lawler, J Organ Behav 15(1):3–15, 1993). In this context, Information systems are a suitable tool to manage individual and organizational knowledge (Alavi and Leidner, MIS Q 25(1):107–136, 2001; Bowman, Inf Syst Manag 19(3):32–40, 2002). This paper introduces a dynamic approach to a competency-based model through IT. We validate such approach through an action research project in RTVE, the largest company and reference public corporation of radio and television in Spain. The action research process in this organization is presented, and the findings highlight the potential benefits of the proposed model, and may be used in facilitating organizational change.  相似文献   
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Collaborative management of natural resources requires that multiple stakeholders come together to negotiate agreements. Who is a stakeholder, what is the boundary and the definition of an issue, and who has legitimacy to convene are interrelated, systemic questions. To address this challenge, this paper provides a conceptual framework with nine Contextual Dimensions. A workshop on collaborative and conflict management of the fishery in Chile, designed and facilitated by the authors, serves as a case study where multiple stakeholders came together to vision desirable futures and explored organizational linkages that could accommodate the different agendas. The workshop is analyzed through a conceptual framework and some conclusions are drawn on the value of experiential learning and on the importance of the iterative consultations that must precede such collaborative management events.Member of the International Support Group (www.isglink.org), a community of practice dedicated to facilitating collaborative learning for natural resource management.  相似文献   
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