886 resultados para Paths and cycles (Graph theory).
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Purpose This chapter explores the ideas of Alasdair MacIntyre and Vaclav Havel and what these two thinkers can contribute to green political theory. Design/methodology/approach This chapter includes examination of some of the key works of Havel and MacIntyre and analysis of these works from the point of view of green political theory. Findings The section ‘Havel and the Imperative to “Live in Truth”: Dissent and Green Politics’ explores Havel’s thought with a particular emphasis on his ethicised notion of political action and critique (‘living in truth’) and his focus on the centrality of dissent (both intellectually and in practice) as central to political critique and action. The section ‘MacIntyre as a Green Thinker: Vulnerability in Political and Moral Theory offers an overview of MacIntyre interpreted as a putative green thinker, with a particular emphasis on his ideas of dependence and vulnerability. The Conclusion attempts to draw some common themes together from both thinkers in terms of what they have to offer contemporary green political thought. Research limitations/implications What is presented here is introductory, ground clearing and therefore necessarily suggestive (as well as under-developed). That is, it is the start of a new area of exploration rather than an analysis based on any exhaustive and comprehensive knowledge of both thinkers. Practical implications This chapter offers some initial lines of exploration for scholars interested in the overlap between green thinking and the work of Havel and MacIntyre. Originality/value This is the first exploration of the connections between the works of Havel and MacIntyre and green political theory.
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Two recent scanning probe techniques were applied to investigate the bipolar twin state of 4-iodo-4'-nitrobiphenyl (INBP) crystals. Solution grown crystals of INBP show typically a morphology which does not express that of a mono-domain polar structure (Fdd2, mm2). From previous X-ray diffraction a twinning volume ratio of similar to 70 : 30 is now explained by two unipolar domains (Flack parameter: 0.075(29)) of opposite orientation of the molecular dipoles, joined by a transition zone showing a width of similar to 140 mm. Scanning pyroelectric microscopy (SPEM) demonstrates a continuous transition of the polarization P from +P into -P across the zone. Application of piezoelectric force microscopy (PFM) confirms unipolar alignment of INBP molecules down to a resolution of similar to 20 nm. A previously proposed real structure for INBP crystals built from lamellae with antiparallel alignment is thus rejected. Anomalous X-ray scattering was used to determine the absolute molecular orientation in the two domains. End faces of the polar axis 2 are thus made up by NO2 groups. Using a previously determined negative pyroelectric coefficient pc leads to a confirmation also by a SPEM analysis. Calculated values for functional group interactions (D...A), (A...A), (D...D) and the stochastic theory of polarity formation allow us to predict that NO2 groups should terminate corresponding faces. Following the present analysis, INBP may represent a first example undergoing dipole reversal upon growth to end up in a bipolar state.
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Research to date suggests that career advancement in call centres (CCs) is relatively uncommon with employees often viewing such employment as a stopgap measure before moving on to something better. This study set out to determine whether such scenarios have changed over time since CCs have become more established in their work organisation, information and communication technology (ICT) and management processes. This study particularly focused on training and development initiatives, how employees access training and development, and whether CCs support career development. Using both qualitative and quantitative methods, these issues are examined within 10 Australian CCs of varying size from various sectors. Two-thirds of respondents stated that they intended to develop a career in the industry and 7 in 10 reported that they believed there were promotional opportunities emerging in their current organisation. Despite these findings, the evidence also suggests that more needs to be done both to create coherent career paths and to establish structured, accredited training programmes for CC employees.
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From the early 1900s, some psychologists have attempted to establish their discipline as a quantitative science. In using quantitative methods to investigate their theories, they adopted their own special definition of measurement of attributes such as cognitive abilities, as though they were quantities of the type encountered in Newtonian science. Joel Michell has presented a carefully reasoned argument that psychological attributes lack additivity, and therefore cannot be quantities in the same way as the attributes of classical Newtonian physics. In the early decades of the 20th century, quantum theory superseded Newtonian mechanics as the best model of physical reality. This paper gives a brief, critical overview of the evolution of current measurement practices in psychology, and suggests the need for a transition from a Newtonian to a quantum theoretical paradigm for psychological measurement. Finally, a case study is presented that considers the implications of a quantum theoretical model for educational measurement. In particular, it is argued that, since the OECD’s Programme for International Student Assessment (PISA) is predicated on a Newtonian conception of measurement, this may constrain the extent to which it can make accurate comparisons of the achievements of different education systems.
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Lignocellulosic biomass pretreatment and the subsequent thermal conversion processes to produce solid, liquid, and gas biofuels are attractive solutions for today's energy challenges. The structural study of the main components in biomass and their macromolecular complexes is an active and ongoing research topic worldwide. The interactions among the three main components, cellulose, hemicellulose, and lignin, are studied in this paper using electronic structure methods, and the study includes examining the hydrogen bond network of cellulose-hemicellulose systems and the covalent bond linkages of hemicellulose-lignin systems. Several methods (semiempirical, Hartree-Fock, and density functional theory) using different basis sets were evaluated. It was shown that theoretical calculations can be used to simulate small model structures representing wood components. By comparing calculation results with experimental data, it was concluded that B3LYP/6-31G is the most suitable basis set to describe the hydrogen bond system and B3LYP/6-31G(d,p) is the most suitable basis set to describe the covalent system of woody biomass. The choice of unit model has a much larger effect on hydrogen bonding within cellulose-hemicellulose system, whereas the model choice has a minimal effect on the covalent linkage in the hemicellulose-lignin system. © 2011 American Chemical Society.
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A self-consistent relativistic two-fluid model is proposed for electron-ion plasma dynamics. A one-dimensional geometry is adopted. Electrons are treated as a relativistically degenerate fluid, governed by an appropriate equation of state. The ion fluid is also allowed to be relativistic, but is cold, nondegenerate, and subject only to an electrostatic potential. Exact stationary-profile solutions are sought, at the ionic scale, via the Sagdeev pseudopotential method. The analysis provides the pulse existence region, in terms of characteristic relativistic parameters, associated with the (ultrahigh) particle density.
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The voltammetry for the reduction of 2-nitrotoluene at a gold microdisk electrode is reported in two ionic liquids: trihexyltetradecylphosphonium tris(pentafluoroethyl)trifluorophosphate ([P-14,P-6,P-6,P-6][FAP]) and 1-ethyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Emim][NTf2]). The reduction of nitrocyclopentane (NCP) and 1-nitrobutane (BuN) was investigated using voltammetry at a gold microdisk electrode in the ionic liquid [P-14,P-6,P-6,P-6][FAP]. Simulated voltammograms, generated through the use of ButlerVolmer theory and symmetric MarcusHush theory, were compared to experimental data, with both theories parametrizing the data similarly well. An experimental value for the Marcusian parameter, 1 was also determined in all cases. For the reduction of 2-nitrotoluene, this was 0.5 +/- 0.1 eV in both solvents, while for NCP and BuN in [P-14,P-6,P-6,P-6][FAP], it was 2 +/- 0.1 and 5 +/- 0.1 eV, respectively. This is attributed to the localization of charge on the nitro group and the primary nitro alkyls increased interaction with the environment, resulting in a larger reorganization energy.
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Reactions that can damage DNA have been simulated using a combination of molecular dynamics and density functional theory. In particular, the damage caused by the attachment of a low energy electron to the nucleobase. Simulations of anionic single nucleotides of DNA in an aqueous environment that was modeled explicitly have been performed. This has allowed us to examine the role played by the water molecules that surround the DNA in radiation damage mechanisms. Our simulations show that hydrogen bonding and protonation of the nucleotide by the water can have a significant effect on the barriers to strand breaking reactions. Furthermore, these effects are not the same for all four of the bases.
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Mathematical models are useful tools for simulation, evaluation, optimal operation and control of solar cells and proton exchange membrane fuel cells (PEMFCs). To identify the model parameters of these two type of cells efficiently, a biogeography-based optimization algorithm with mutation strategies (BBO-M) is proposed. The BBO-M uses the structure of biogeography-based optimization algorithm (BBO), and both the mutation motivated from the differential evolution (DE) algorithm and the chaos theory are incorporated into the BBO structure for improving the global searching capability of the algorithm. Numerical experiments have been conducted on ten benchmark functions with 50 dimensions, and the results show that BBO-M can produce solutions of high quality and has fast convergence rate. Then, the proposed BBO-M is applied to the model parameter estimation of the two type of cells. The experimental results clearly demonstrate the power of the proposed BBO-M in estimating model parameters of both solar and fuel cells.
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Contested Open Spaces?: Access and control issues in Tundikhel, Kathmandu
Public spaces play a role of political, economic and cultural transformation of cities and the impact of these transformations on the nature of public space.
Urban open space(s) in Kathmandu have been an important part of the city’s urbanism. Historically they have played an important role in the city as spaces for religious, cultural, social and political and military activities during the 300 years of unified monarchy. Throughout the civil war period (Maoist insurgency between 1996 and 2006) they became material locations for political activities, and a site for protests and dharnas. In post-conflict Kathmandu, especially since the abolition of Monarchy in May 28, 2008, these spaces are increasingly seen being claimed by street hawkers, informal sellers and individuals reflecting a new set of users and functions, whereas a significant part of Tundikhel still remains under the military occupation posing important questions around access, identity and control of an important space.
Public spaces are broadly defined as crossroads where different paths and trajectories meet, sometimes overlapping and other times colliding (Madanipour, 2003). Using Tudikhel in Kathmandu, this research examines the increasing collision and contestations witnessed through social, political and neoliberal interactions. It explores how spaces are constantly
contested, negotiated and as a result reshaped through these interactions. It is observed that multiple forces are at play to gain control and access of this important open space, leading to increasing fragmentation of the space, and erosion of its historic significance both as cultural venue and a symbol of democracy in modern Nepal. It is argued that increasing disconnection of Tudikhel from wider urban setting has contributed to exacerbation of these contestations
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In this study, the behaviour of iron ore fines with varying levels of adhesion was investigated using a confined compression test and a uniaxial test. The uniaxial test was conducted using the semi-automated uniaxial EPT tester in which the cohesive strength of a bulk solid is evaluated from an unconfined compression test following a period of consolidation to a pre-defined vertical stress. The iron ore fines were also tested by measuring both the vertical and circumferential strains on the cylindrical container walls under vertical loading in a separate confined compression tester - the K0 tester, to determine the lateral pressure ratio. Discrete Element Method simulations of both experiments were carried out and the predictions were compared with the experimental observations. A recently developed DEM contact model for cohesive solids, an Elasto-Plastic Adhesive model, was used. This particle contact model uses hysteretic non-linear loading and unloading paths and an adhesion parameter which is a function of the maximum contact overlap. The model parameters for the simulations are phenomenologically based to reproduce the key bulk characteristics exhibited by the solid. The simulation results show a good agreement in capturing the stress history dependent behaviour depicted by the flow function of the cohesive iron ore fines while also providing a reasonably good match for the lateral pressure ratio observed during the confined compression K0 tests. This demonstrates the potential for the DEM model to be used in the simulation of bulk handling applications.
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Realistic Evaluation assumes that all programmes implemented in practice have an underlying theory to explain how a particular intervention is meant to work. The purpose of realist evaluation is to test the theoretical propositions underpinning the implementation of a programme in order to understand how and why it works, or might not work, in certain circumstances. The first stage of the realist evaluation is to track and articulate the programme theories to determine the evidence on the ‘official conjecture’ (Pawson et al 2004 pg 16) of how the programme is suppose to work in practice. These official conjectures are then tested and refined by gathering empirical evidence to establish causal relationships between a programme and its outcome. Evaluation of the factors and interactions between factors, supporting or hindering the implementation of a programme in practice facilitate theory refinement. Theory refinement is viewed as an iterative and cyclical process undertaken to synthesise the empirical evidence and develop mid-range theories which can be generalised and applied to other programmes to improve implementation and sustainability. In this symposium an example of realist evaluation used to test and refine the theory underpinning the implementation of Early Warning Systems (EWS) is provided to clarify how this theory driven approach can be applied in practice.
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We study the problem of determining whether or not a graph G has an induced matching that dominates every edge of the graph, which is also known as efficient edge domination. This problem is known to be NP-complete in general as well as in some restricted domains, such as bipartite graphs or regular graphs. In this paper, we identify a graph parameter to which the complexity of the problem is sensible and produce results of both negative (intractable) and positive (solvable in polynomial time) type. © 2009 Springer Berlin Heidelberg.
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An induced matching of a graph G is a matching having no two edges joined by an edge. An efficient edge dominating set of G is an induced matching M such that every other edge of G is adjacent to some edge in M. We relate maximum induced matchings and efficient edge dominating sets, showing that efficient edge dominating sets are maximum induced matchings, and that maximum induced matchings on regular graphs with efficient edge dominating sets are efficient edge dominating sets. A necessary condition for the existence of efficient edge dominating sets in terms of spectra of graphs is established. We also prove that, for arbitrary fixed p ≥ 3, deciding on the existence of efficient edge dominating sets on p-regular graphs is NP-complete. © 2008 Elsevier B.V. All rights reserved.
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The problem of determining a maximum matching or whether there exists a perfect matching, is very common in a large variety of applications and as been extensively studied in graph theory. In this paper we start to introduce a characterisation of a family of graphs for which its stability number is determined by convex quadratic programming. The main results connected with the recognition of this family of graphs are also introduced. It follows a necessary and sufficient condition which characterise a graph with a perfect matching and an algorithmic strategy, based on the determination of the stability number of line graphs, by convex quadratic programming, applied to the determination of a perfect matching. A numerical example for the recognition of graphs with a perfect matching is described. Finally, the above algorithmic strategy is extended to the determination of a maximum matching of an arbitrary graph and some related results are presented.