693 resultados para Catégories compactes closes


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This contribution closes this special issue of Hydrology and Earth System Sciences concerning the assessment of nitrogen dynamics in catchments across Europe within a semi-distributed Integrated Nitrogen model for multiple source assessment in Catchments (INCA). New developments in the understanding of the factors and processes determining the concentrations and loads of nitrogen are outlined. The ability of the INCA model to simulate the hydrological and nitrogen dynamics of different European ecosystems is assessed and the results of the first scenario analyses investigating the impacts of deposition, climatic and land-use change on the nitrogen dynamics are summarised. Consideration is given as to how well the model has performed as a generic too] for describing the nitrogen dynamics of European ecosystems across Arctic, Maritime. Continental and Mediterranean climates, its role in new research initiatives and future research requirements.

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This contribution closes this special issue of Hydrology and Earth System Sciences concerning the assessment of nitrogen dynamics in catchments across Europe within a semi-distributed Integrated Nitrogen model for multiple source assessment in Catchments (INCA). New developments in the understanding of the factors and processes determining the concentrations and loads of nitrogen are outlined. The ability of the INCA model to simulate the hydrological and nitrogen dynamics of different European ecosystems is assessed and the results of the first scenario analyses investigating the impacts of deposition, climatic and land-use change on the nitrogen dynamics are summarised. Consideration is given as to how well the model has performed as a generic too] for describing the nitrogen dynamics of European ecosystems across Arctic, Maritime. Continental and Mediterranean climates, its role in new research initiatives and future research requirements.

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If people monitor a visual stimulus stream for targets they often miss the second (T2) if it appears soon after the first (T1)-the attentional blink. There is one exception: T2 is often not missed if it appears right after T1, i.e., at lag 1. This lag-l sparing is commonly attributed to the possibility that T1 processing opens an attentional gate, which may be so sluggish that an early T2 can slip in before it closes. We investigated why the gate may close and exclude further stimuli from processing. We compared a control approach, which assumes that gate closing is exogenously triggered by the appearance of nontargets, and an integration approach, which assumes that gate closing is under endogenous control. As predicted by the latter but not the former, T2 performance and target reversals were strongly affected by the temporal distance between T1 and T2, whereas the presence or the absence of a nontarget intervening between T1 and T2 had little impact. (c) 2005 Elsevier B.V. All rights reserved.

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We outline a method to determine the direction of solar open flux transport that results from the opening of magnetic clouds (MCs) by interchange reconnection at the Sun based solely on in-situ observations. This method uses established findings about i) the locations and magnetic polarities of emerging MC footpoints, ii) the hemispheric dependence of the helicity of MCs, and iii) the occurrence of interchange reconnection at the Sun being signaled by uni-directional suprathermal electrons inside MCs. Combining those observational facts in a statistical analysis of MCs during solar cycle 23 (period 1995 – 2007), we show that the time of disappearance of the northern polar coronal hole (1998 – 1999), permeated by an outward-pointing magnetic field, is associated with a peak in the number of MCs originating from the northern hemisphere and connected to the Sun by outward-pointing magnetic field lines. A similar peak is observed in the number of MCs originating from the southern hemisphere and connected to the Sun by inward-pointing magnetic field lines. This pattern is interpreted as the result of interchange reconnection occurring between MCs and the open field lines of nearby polar coronal holes. This reconnection process closes down polar coronal hole open field lines and transports these open field lines equatorward, thus contributing to the global coronal magnetic field reversal process. These results will be further constrainable with the rising phase of solar cycle 24.

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The record of deposition of tephras in Europe and the North Atlantic during the period 18.5–8.0 14C ka BP (the Last Termination and Early Holocene) is reviewed. Altogether, 34 tephras originating from four main volcanic provinces (Iceland, the Eifel district, the Massif Central and Italy) have been identified so far in geological sequences spanning this time–interval. Most of the records have been based, until very recently, on observations of visible layers of tephras. Here, we report on the potential for extending the areas over which some of the tephras can be traced by the search for layers of micro–tephra, which are not visible to the naked eye, and on the use of geochemical methods to correlate them with known tephra horizons. This approach has greatly extended the area in Northern Europe over which the Vedde Ash can be traced. The same potential exists in southern Europe, which is demonstrated for the first time by the discovery of a distinct layer of micro–tephra of the Neapolitan Yellow Tuff in a site in the Northern Apennines in Italy, far to the north of the occurrences of visible records of this tephra. The paper closes by considering the potential for developing a robust European tephrostratigraphy to underpin the chronology of records of the Last Termination and Early Holocene, thereby promoting a better understanding of the nature, timing and environmental effects of the abrupt climatic changes that characterized this period.

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This paper examines the ethics of the Clean Development Mechanism (CDM) in its architecture, processes and outcomes and its potential to allocate resources to the poor as ‘ethical development’. Two specific examples of CDM projects help us to explore some of the quandaries that seem to be quickly defining operating procedure for the CDM in its efforts to bring entitlementsto the poor. The paper concludes with reflections on the normative and social complications of the CDM and closes with three key areas of further investigation.

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This chapter aims to provide an overview of building simulation in a theoretical and practical context. The following sections demonstrate the importance of simulation programs at a time when society is shifting towards a low carbon future and the practice of sustainable design becomes mandatory. The initial sections acquaint the reader with basic terminology and comment on the capabilities and categories of simulation tools before discussing the historical development of programs. The main body of the chapter considers the primary benefits and users of simulation programs, looks at the role of simulation in the construction process and examines the validity and interpretation of simulation results. The latter half of the chapter looks at program selection and discusses software capability, product characteristics, input data and output formats. The inclusion of a case study demonstrates the simulation procedure and key concepts. Finally, the chapter closes with a sight into the future, commenting on the development of simulation capability, user interfaces and how simulation will continue to empower building professionals as society faces new challenges in a rapidly changing landscape.

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La Suite Vulgate, une œuvre d'orientation à la fois romanesque et historique, interroge la pertinence des constructions et catégories génériques dans la littérature médiévale. Afin de mieux cerner le statut de cette œuvre hybride, cet article explore les questions de l'écriture de l'histoire, la terminologie à travers laquelle l'œuvre s'auto-désigne, son rapport à la temporalité, et le mode de représentation de l'histoire que propose le texte.

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The paper reviews the leading diagramming methods employed in system dynamics to communicate the contents of models. The main ideas and historical development of the field are first outlined. Two diagramming methods—causal loop diagrams (CLDs) and stock/flow diagrams (SFDs)—are then described and their advantages and limitations discussed. A set of broad research directions is then outlined. These concern: the abilities of different diagrams to communicate different ideas, the role that diagrams have in group model building, and the question of whether diagrams can be an adequate substitute for simulation modelling. The paper closes by suggesting that although diagrams alone are insufficient, they have many benefits. However, since these benefits have emerged only as ‘craft wisdom’, a more rigorous programme of research into the diagrams' respective attributes is called for.

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This essay reviews the ways in which literary manuscripts may be considered to be archivally unique, as well as valuable in all senses of the word, and gives a cautious appraisal of their future in the next ten to twenty years. It reviews the essential nature of literary manuscripts, and especially the ways in which they form “split collections”. This leads to an assessment of the work of the Diasporic Literary Archives network from 2012 to 2014, and some of the key findings. The essay closes with reflections on the future of literary manuscripts in the digital age – emerging trends, research findings, uncertainties and unknowns.

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At its inception, the paradigm of system dynamics was deliberately made distinct from that of OR. Yet developments in soft OR now have much in common with current system dynamics modeling practice. This article briefly traces the parallel development of system dynamics and soft OR, and argues that a dialogue between the two would be mutually rewarding. to support this claim, examples of soft OR tools are described along with some of the field’s philosophical grounding and current issues. Potential benefits resulting from a dialogue are explored, with particular emphasis on the methodological framework of system dynamics and the need for a complementarist approach. The article closes with some suggestions on how to begin learning from.

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China’s financial system has experienced a series of major reforms in recent years. Efforts have been made towards introducing the shareholding system in state-owned commercial banks, restructuring of securities firms, re-organising equity of joint venture insurance companies, further improving the corporate governance structure, managing financial risks and ultimately establishing a system to protect investors (Xinhua, 2010). Financial product innovation, with the further opening up of financial markets and the development of the insurance and bond market, has increased liquidity as well as reduced financial risks. The U.S. subprime crisis indicated the benefit of financial innovations for the economy, but without proper control, they may lead to unexpected consequences. Kirkpatrick (2009) argues that failures and weaknesses in corporate governance arrangements and insufficient accounting standards and regulatory requirements attributed to the financial crisis. Similar to the financial crises of the last decade, the global financial crisis which sparked in 2008, surfaced a variety of significant corporate governance failures: the dysfunction of market mechanisms, the lack of transparency and accountability, misaligned compensation arrangements and the late response of government, all which encouraged management short-termism, poor risk management, as well as some fraudulent schemes. The unique characteristics of the Chinese banking system are an interesting point for studying post-crisis corporate governance reform. Considering that China modelled its governance system on the Anglo-American system, this paper examines the impact of the financial crisis on corporate governance reform in developed economies, and particularly, China’s reform of its financial sector. The paper further analyses the Chinese government’s role in bank supervision and risk management. In this regard, the paper contributes to the corporate governance literature within the Chinese context by providing insights into the contributing factors to the corporate governance failure that led to the global financial crisis. It also provides policy recommendations for China’s policy makers to seriously consider. The results suggest a need for the re-examination of corporate governance adequacy and the institutionalisation of business ethics. The paper’s next section provides a review of China’s financial system with reference to the financial crisis, followed by a critical evaluation of a capitalistic system and a review of Anglo-American and Continental European models. It then analyses the need for a new corporate governance model in China by considering the bank failures in developed economies and the potential risks and inefficiencies in a current State controlled system. The paper closes by reflecting the need for Chinese policy makers to continually develop, adapt and rewrite corporate governance practices capable of meeting the new challenge, and to pay attention to business ethics, an issue which goes beyond regulation.

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This paper makes a theoretical case for using these two systems approaches together. The theoretical and methodological assumptions of system dynamics (SD) and soft system methodology (SSM) are briefly described and a partial critique is presented. SSM generates and represents diverse perspectives on a problem situation and addresses the socio-political elements of an intervention. However, it is weak in ensuring `dynamic coherence'. consistency between the intuitive behaviour resulting from proposed changes and behaviour deduced from ideas on causal structure. Conversely, SD examines causal structures and dynamic behaviours. However, whilst emphasising the need for a clear issue focus, it has little theory for generating and representing diverse issues. Also, there is no theory for facilitating sensitivity to socio-political elements. A synthesis of the two called ‘Holon Dynamics' is proposed. After an SSM intervention, a second stage continues the socio-political analysis and also operates within a new perspective which values dynamic coherence of the mental construct - the holon - which is capable of expressing the proposed changes. A model of this holon is constructed using SD and the changes are thus rendered `systemically desirable' in the additional sense that dynamic consistency has been confirmed. The paper closes with reflections on the proposal and the need for theoretical consistency when mixing tools is emphasised.

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The past few years have seen a significant resurgence of interest in ‘management games’ and ‘management flight simulators’, one particularly active source of such work being the system dynamics community. After proposing a distinction between games and simulations, this paper provides some background to these developments by briefly describing the historical roots of the field and the fundamental ideas of the system dynamics community, which are now giving rise to ‘microworlds’. The training advantages of management simulations and games are then discussed. The paper closes with a note on the research and findings of the system dynamics field and by offering some words of warning on the perils of simulation and game use. Two scenarios for how the use of simulations and games as management education devices might develop in the future are proposed. An Appendix describes five examples of very different types of management simulations and games.

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The date of the Late Bronze Age Minoan eruption of the Thera volcano has provoked much debate among archaeologists, not least in a recent issue of Antiquity (‘Bronze Age catastrophe and modern controversy: dating the Santorini eruption’, March 2014). Here, the authors respond to those recent contributions, citing evidence that closes the gap between the conclusions offered by previous typological, stratigraphic and radiometric dating techniques. They reject the need to choose between alternative approaches to the problem and make a case for the synchronisation of eastern Mediterranean and Egyptian chronologies with agreement on a ‘high’ date in the late seventeenth century BC for the Thera eruption.