885 resultados para post-structural theory


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The diazocarbene radical, CNN, and the ions CNN(+) and CNN(-) were investigated at a high level of theory. Very accurate structural parameters for the states X(3)Sigma(-) and A(3)Pi of CNN, and X(2)Pi of both CNN(+) and CNN(-) were obtained with the UCCSD(T) method using correlated-consistent basis functions with extrapolations to the complete basis set limit, with valence only and also with all electrons correlated. Harmonic and anharmonic frequencies were obtained for all species and the Renner parameter and average frequencies evaluated for the Pi states. At the UCCSD(T)/CBS(T-5) level of theory, Delta(f)H(0 K) = 138.89 kcal/mol and Delta(f)H(298 K) = 139.65 kcal/mol were obtained for diazocarbene; for the ionization potential and the electron affinity of CNN, 10.969 eV (252.95 kcal/mol), and 1.743 eV (40.19 kcal/mol), respectively, are predicted. Geometry optimization was also carried out with the CASSCF/MRCI/CBS(T-5) approach for the states X(3)Sigma(-) A(3)Pi, and a(1)Delta of CNN, and with the CASSCF/MRSDCI/aug-cc-pVTZ approach for the states b(1)Sigma(+), c(1)Pi, d(1)Sigma(-), and B(3)Sigma(-), and excitation energies (T(e)) evaluated. Vertical energies were calculated for 15 electronic states, thus improving on the accuracy of the five transitions already described, and allowing for a reliable overview of a manifold of other states, which is expected to guide future spectroscopic experiments. This study corroborates the experimental assignment for the vertical transition X (3)Sigma(-) <- E (3)Pi.

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Structural and thermodynamic stabilities of monomers and dimers of trialkylphosphine oxides (TRPO) were Studied using quantum chemistry calculations. Density functional theory calculations were carried Out and the structures Of four TRPO have been determined: TMPO (methyl; R = CH(3)), TEPO (ethyl; R = CH(3)CH(2)), TBPO (n-butyl; R = CH(3)(CH(2))(3)), and TOPO (n-octyl; R = CH(3)(CH(2))(7)). TRPO homodimers were investigated considering two isomeric possibilities for each dimer. Relative binding energies and the enthalpic and entropic contributions to the Gibbs free energy were Calculated for all dimers. The formation of dimers from the individual monomeric TRPO species as a function of temperature was also analyzed. (C) 2008 Wiley Periodicals, Inc. Int J Quantum Chem 109: 250-258, 2009

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Quantum mechanical calculations at the B3LYP theory level, together with the 6-31G* basis set, were employed to obtain the energy, ionization potential, and polarizabilites for dipyridamole and derivatives, which are compared with their biological activity. Density functional calculations of the spin densities were performed for radical formed by electron abstraction of dipyridamole and derivatives. The unpaired electron remains in dipyridamole is localized on the nitrogen atoms in the substituent positions 1, 3, 5, 7, 11, 12, 13, 14, with participation of the 9 and 10 carbons in the pyrimido-pyrimidine ring. The antioxidant activity is related with ionization potential, polarizability and Log P.

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The floristics and structure of heathland vegetation exhibiting symptoms of Phytophthora cinnamomi Rands infestation was assessed at two sites in heathlands at Anglesea, Victoria. There were significant effects in both floristics and structure. Thirteen heathland species were significantly less abundant in diseased areas and 23 species were more abundant. Diseased (infested) vegetation, when compared with non-diseased areas, had less cover of Xanthorrhoea australis and shrub species and a greater cover of sedges, grasses and open ground. Structural differences were observed between heights 0 and 0.6 m, with a decline in cover recorded in diseased vegetation. Non-metric multidimensional scaling ordination of the floristic data showed a clear separation of diseased and non-diseased vegetation and that changes in floristic composition post-infestation were similar at both sites. Although there was some evidence of regeneration of X. australis, the recovery capacity of other susceptible species at Anglesea is unknown. The long-term consequences of loss of species and structure in the eastern Otways mean that the vegetation is unlikely to return to former status, especially if the pathogen continues to reinfect.

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This article argues that it is time for the complete abolition of feudal tenure in Australian land law and its replacement with an allodial model better able to promote proprietary independence, equality and cultural neutrality. The article considers the questionable constitutional legitimacy of adopting strict feudal tenets in a territory already inhabited by indigenous occupants. It goes on to examine the various legitimation devices that the courts have utilised to sustain the feudal construct and the effect that Mabo has had upon feudal orthodoxy. In particular, the article outlines why post-Mabo tenure is incapable of embracing a pluralist land system; it is suggested that the Eurocentric character of feudal tenure and the structural impediments associated with the acceptance of a non-Crown title prevent it from ever being able to effectively integrate native title into the structure of property law. In light of this, the article argues that post-Mabo tenure lacks both legal and social legitimacy and the 'disinterested' perpetuation of this system must be brought to an end. The article argues that the time has well and truly come to replace feudal tenure with an allodial model based broadly on the system that has developed in the United States but with particularised adaptations. The removal of the Crown and its associated cultural assumptions from the land framework would, it is argued, allow land interests to develop according to their individual cultural origins. This would create a more responsive and balanced system better equipped to embrace the developments of contemporary common law jurisprudence.

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Rhetorical theory's contemporary involvement with semiotics is overlooked in much current public relations scholarship. This paper aims to 'make a difference' in this respect. There is a need for this change of perspective in view of a call for a new direction in public relations theory. This call came in the final Public Relations Division session at the July, 2003 International Communication Association Convention in San Diego. That panel discussion was titled: 'What Should be the Focus of Public Relations?' The session concluded that a turn towards 'rhetorical theory' was needed. This paper argues that such a turn would pose interesting theoretical and political challenges for a field which has not fully caught up with post-modern ideas. It points out how involvement with the contemporary 'rhetorical turn' paradigm and this paradigm's link to semiotics, would take public relations studies into interesting conceptual and political regions.

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This study examines the influence of distributive and interactional justice and disconfirmation on customers’ postrecovery satisfaction evaluations, and in so doing, combines, for the first time, two existing instruments to operationalise the interactional justice construct. Using Structural Equation Modelling, the findings suggest that while both disconfirmation and justice are important predictors of satisfaction, distributive justice has the greatest influence. The research presented here reports on a section of a larger experiment-based study examining how customers’ postrecovery satisfaction evaluations are influenced by the way in which the organisation responds to the failure.

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This article highlights the theoretical notion of Postmodernism and attempts to place Tourism research into the postmodernism frame of reference. This is achieved by a brief description of the theory and further development in section two which reviews the challenges of postmodernism to research in the tourism field. There is then an endeavour to intertwine the constructs of postmodernist theory and to illustrate how it can relate to the tourism industry and in particular contemporary tourism. Indeed, we argue that even though a number of authors have begun to chart the sociological dimensions of post-modem tourism they have done so without highlighting the definitions and structure of postmodernist theory. Examples are given in order to support the theoretical approach to research which we suggest in this paper and every effort is undertaken in order to argue that postmodernist research in tourism can be beneficial and fruitful tor future directions. Consequently this article attempts to dispel some of the widespread bemusement concerning post-modem theories and post-modern tourism by reviewing some of the recent developments in the area and suggesting further research.

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The aim of this study is to assess whether universities are meeting the needs of students in large marketing classes. In so doing the study investigates the application of self determination theory and psychological needs satisfaction. The basic needs scale, comprising of three constructs; Control, Competence and Caring was adapted and used to evaluate students’ perception of an introductory marketing subject. The study used a multi-method approach consisting of a literature review, a qualitative phase involving in-depth interviews with marketing teaching staff and focus groups with marketing students and a survey of students about introductory level marketing. An adapted version of the basic psychological needs scale was included in a questionnaire that was administered to a convenience sample of 366 students. MANOVA, ANOVA and descriptive statistics were used to analyse the data. The results show that the psychological needs satisfaction of many students are not being fully realised. It was also found that marketing degree students enjoyed the challenges and were more stimulated by the subject. The higher achieving students enjoyed the challenge of the subject more than the lower achieving students. As a result of this study, there are three suggestions for further research. Firstly, further study should compare subjects, with relatively small enrolments, to those with large enrolments to corroborate the value of this method of assessing student satisfaction. Secondly, the use of a larger sample across other universities would confirm whether these findings hold for other institutions. Finally, it is suggested that a structural model should be developed to extend this investigation of student satisfaction and the constructs used in the study.

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Constructivist and socio-cultural perspectives in mathematics education highlight the crucial role that activity plays in mathematical development and learning. Activity theory provides a socio-cultural lens to help analyse human behaviour, including that which occurs in classrooms. It provides a framework for co-ordinating constructivist and socio-cultural perspectives in mathematics learning. In this paper, we adopt Cole and Engeström's (1991) model of activity theory to examine the mediation offered by the calculator as a tool for creating and supporting learning processes of young children in the social environment of their classroom. By adopting this framework, data on young children's learning outcomes in number, when given free access to calculators, can be examined not only in terms of the mediating role of the calculator, but also within the broader context of the classroom community, the teachers' beliefs and intentions, and the classroom norms and the division of labour. Use of this model in a post hoc situation suggests that activity theory can play a significant role in the planning of future classroom research.

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An enduring aspect of the operation of the criminal justice system in Australia has been the disproportionate representation of indigenous persons. Under current sentencing principles, aboriginality can be taken into account as a factor in mitigation because of the nature of social and economic disadvantage suffered by indigenous communities. It is contended that such an approach is inadequate as it fails to comprehend the reasons for that disadvantage. In short, the effects of colonialism and dispossession. An account of punishment will be developed that colonialism and dispossession cannot be omitted from any satisfactory account of the theory and history of punishment of indigenous persons. By relying on the notion of ‘just deserts’ an account of punishment will be proposed that extends the categories currently put forward to justify punishing indigenous persons. Traditional, philosophical accounts of punishment and insights from critical race theory will both be used in an attempt to articulate what ‘just deserts’ means in the context of a post-colonial society.

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Purpose – The purpose of this article is to present an empirical analysis of complex sample data with regard to the biasing effect of non-independence of observations on standard error parameter estimates. Using field data structured in the form of repeated measurements it is to be shown, in a two-factor confirmatory factor analysis model, how the bias in SE can be derived when the non-independence is ignored.

Design/methodology/approach – Three estimation procedures are compared: normal asymptotic theory (maximum likelihood); non-parametric standard error estimation (naïve bootstrap); and sandwich (robust covariance matrix) estimation (pseudo-maximum likelihood).

Findings – The study reveals that, when using either normal asymptotic theory or non-parametric standard error estimation, the SE bias produced by the non-independence of observations can be noteworthy.

Research limitations/implications –
Considering the methodological constraints in employing field data, the three analyses examined must be interpreted independently and as a result taxonomic generalisations are limited. However, the study still provides “case study” evidence suggesting the existence of the relationship between non-independence of observations and standard error bias estimates.

Originality/value – Given the increasing popularity of structural equation models in the social sciences and in particular in the marketing discipline, the paper provides a theoretical and practical insight into how to treat repeated measures and clustered data in general, adding to previous methodological research. Some conclusions and suggestions for researchers who make use of partial least squares modelling are also drawn.

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Nanostructured and ultra-fine grained metals have higher strength but extremely limited ductility compared to coarse grained metals. However, their ductility can be greatly improved by introducing a specific range of grain sizes in the microstructures. In the paper, multiscale unit cell approach (UCA) is developed and applied to predict the averaged stress-strain relations of the multiscale microstructure metals. The unit cell models are three-phase structured at different scale lengths of 100 nm, 1 μm and 10 μm with different volume fractions and periodic boundary conditions. The contributions of multi-scale microstructures to the macroscopic structural properties of metals are also studied using a analytic approach—two-step mean-field method (TSMF), where three microstructural parameters are introduced and thus mechanical properties such as strength and ductility are presented as a function of these parameters. For verification of these proposed numerical and theoretical algorithms, the structural properties of the pure nickel with three-grain microstructures are studied and the results from FEA and the proposed theory have good agreement.

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Purpose: To consider how leadership theories have helped or hindered raising the profile of women in management and leadership roles.

Design/methodology/approach: This paper traces the earlier leadership theories through to the contemporary research on transactional and transformational leadership styles and offers a viewpoint on how each theory has contributed, or otherwise, to an awareness and acceptance of women in management and leadership roles.

Findings:  In 1990, research began to report gender differences in leadership styles with female managers being seen in positive terms as participative, democratic leaders. More recent work reports that women are believed to exhibit more transformational leadership style than their male colleagues, and this is equated with effective leadership.

Research limitations/implications
:  All of the earlier theories on leadership excluded women and this exacerbated the problem of women not being seen as an appropriate fit in a management or leadership role. Recent findings clearly describe that the transformational qualities of leadership that women exhibit are required by the flatter organisational structures of today. Therefore, a more positive outcome for women advancing to senior roles of management or leadership may be observed in the future.

Originality/value:  The paper reviews the major leadership theories, and links these to a timeframe to illustrate how women were not visible in a management context until relatively recently. Such an omission may have contributed to the continuing low numbers of women who advance to senior management and leadership roles.