4,620 research outputs found

    A regularized inverted perturbation approach method: potential energy curve of the 41Σu+4^1\Sigma^+_u state in Na2Na_2

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    We describe a modification of the inverted perturbation approach method allowing to construct physically sensible potential energy curves for electronic states of diatomic molecules even when some parts of the potential are not adequately characterized by the experimental data. The method is based on a simple regularization procedure, imposing an additional constraint on the constructed potential curve. In the present work it is applied to the double minimum 41Σu+^1\Sigma^{+}_{\mathrm u} state of Na2_2, observed experimentally by polarization labeling spectroscopy technique.Comment: 15 pages, 3 figure

    Gender, Part-time Employment and Employee Participation in the Workplace: Comparing Australia and the European Union

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    The international trend in the growth and incidence of 'no n-standard employment', and its highly gendered nature, is well documented. For ease of definition, and because of the nature of the available data, we focus upon part-time employment in this paper. Employee participation may be defined as any workplace process which 'allows employees to exert some influence over their work and the conditions under which they work' (Strauss 1998). It may be divided into two main approaches, direct participation and indirect or representative participation. Direct participation involves the employee in job or task-oriented decision-making in the production process at the shop or office floor level. Indirect or representative forms of participation include joint consultative committees, works councils, and employee members of boards of directors or management. In the EU context statutory works councils are the most common expression of representative participation, but in Australia, consultative committees resulting from union/employer agreement or unilateral management initiative are the more common form. All of these forms of employee participation raise important issues concerning part time employees. Effective participation has two further major requirements which also may disadvantage part timers. First, there is a ge neral consensus in the participation literature that training is required for effective direct or representative participation. Secondly, effective communication between management and employees is required for participation, preferably involving a two-way information flow. The issue is of further significance since it has decided gender implications. This paper seeks to redress this relative insularity in the literature by examining some broad trends in this area in Australia and the EU. It analyses survey data at a national level in Australia and compares with some survey data generated in the EU by the EPOC project and analysed by Juliet Webster along the lines which we suggest here. It tests the hypothesis that the growth of one non-standard form of employment, part-time employment, diminishes the access to participation in the workplace enjoyed by female workers in comparison with their male colleagues, and finds that the hypothesis is strongly confirmed. This has major implications for workplace equity, and for organisational efficiency.gender, part-time employment, employee participation, Australia, European Union

    Bifurcations of dynamical systems with sliding : derivation of normal-form mappings

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    This paper is concerned with the analysis of so-called sliding bifurcations in n-dimensional piecewise-smooth dynamical systems with discontinuous vector field. These novel bifurcations occur when the system trajectory interacts with regions on the discontinuity set where sliding is possible. The derivation of appropriate normal-form maps is detailed. It is shown that the leading-order term in the map depends on the particular bifurcation scenario considered. This is in turn related to the possible bifurcation scenarios exhibited by a periodic orbit undergoing one of the sliding bifurcations discussed in the paper. A third-order relay system serves as a numerical example.</p

    Transport analysis of K+ production in proton-nucleus reactions

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    The production of K+K^+ mesons in proton-nucleus collisions from 1.0 to 2.3 GeV is analyzed with respect to one-step nucleon-nucleon (NNNYK+(NN\to N Y K^+) and two-step Δ\Delta-nucleon (ΔNK+YN(\Delta N \to K^+ Y N) or pion-nucleon (πNK+Y(\pi N \to K^+ Y ) production channels on the basis of a coupled-channel transport approach (CBUU) including the kaon final-state-interactions (FSI). Momentum-dependent potentials for the nucleon, hyperon and kaon in the final state are included as well as K+K^+ elastic rescattering in the target nucleus. The transport calculations are compared to the experimental K+K^+ spectra taken at COSY-J\"ulich. Our systematic analysis of K+K^+ spectra from 12C^{12}C, 63Cu^{63}Cu, 107Ag^{107}Ag and 197Au^{197}Au targets as well as their momentum differential ratios gives a repulsive K+K^+ potential of 20±520\pm 5 MeV at normal nuclear matter density.Comment: 7 pages, 5 figures, submitted to Eur. Phys. J.

    Multipartite quantum correlations: symplectic and algebraic geometry approach

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    We review a geometric approach to classification and examination of quantum correlations in composite systems. Since quantum information tasks are usually achieved by manipulating spin and alike systems or, in general, systems with a finite number of energy levels, classification problems are usually treated in frames of linear algebra. We proposed to shift the attention to a geometric description. Treating consistently quantum states as points of a projective space rather than as vectors in a Hilbert space we were able to apply powerful methods of differential, symplectic and algebraic geometry to attack the problem of equivalence of states with respect to the strength of correlations, or, in other words, to classify them from this point of view. Such classifications are interpreted as identification of states with `the same correlations properties' i.e. ones that can be used for the same information purposes, or, from yet another point of view, states that can be mutually transformed one to another by specific, experimentally accessible operations. It is clear that the latter characterization answers the fundamental question `what can be transformed into what \textit{via} available means?'. Exactly such an interpretations, i.e, in terms of mutual transformability can be clearly formulated in terms of actions of specific groups on the space of states and is the starting point for the proposed methods.Comment: 29 pages, 9 figures, 2 tables, final form submitted to the journa

    Classification of Low Dimensional Lie Super-Bialgebras

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    A thorough analysis of Lie super-bialgebra structures on Lie super-algebras osp(1|2) and super-e(2) is presented. Combined technique of computer algebraic computations and a subsequent identification of equivalent structures is applied. In all the cases Poisson-Lie brackets on supergroups are found. Possibility of quantizing them in order to obtain quantum groups is discussed. It turns out to be straightforward for all but one structures for super-E(2) group.Comment: 15 pages, LaTe

    Towards Data Mining in Large and Fully Distributed Peer-To-Peer Overlay Networks

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    The Internet, which is becoming a more and more dynamic, extremely heterogeneous network has recently became a platform for huge fully distributed peer-to-peer overlay networks containing millions of nodes typically for the purpose of information dissemination and file sharing. This paper targets the problem of analyzing data which are scattered over a such huge and dynamic set of nodes, where each node is storing possibly very little data but where the total amount of data is immense due to the large number of nodes. We present distributed algorithms for effectively calculating basic statistics of data using the recently introduced newscast model of computation and we demonstrate how to implement basic data mining algorithms based on these techniques. We will argue that the suggested techniques are efficient, robust and scalable and that they preserve the privacy of data

    Adventures of a tidally induced bar

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    Using N-body simulations, we study the properties of a bar induced in a discy dwarf galaxy as a result of tidal interaction with the Milky Way. The bar forms at the first pericentre passage and survives until the end of the evolution at 10 Gyr. Fourier decomposition of the bar reveals that only even modes are significant and preserve a hierarchy so that the bar mode is always the strongest. They show a characteristic profile with a maximum, similar to simulated bars forming in isolated galaxies and observed bars in real galaxies. We adopt the maximum of the bar mode as a measure of the bar strength and we estimate the bar length by comparing the density profiles along the bar and perpendicular to it. The bar strength and the bar length decrease with time, mainly at pericentres, as a result of tidal torques acting at those times and not to secular evolution. The pattern speed of the bar varies significantly on a time-scale of 1 Gyr and is controlled by the orientation of the tidal torque from the Milky Way. The bar is never tidally locked, but we discover a hint of a 5/2 orbital resonance between the third and fourth pericentre passage. The speed of the bar decreases in the long run so that the bar changes from initially rather fast to slow in the later stages. The boxy/peanut shape is present for some time and its occurrence is preceded by a short period of buckling instability

    Lie Bialgebra Structures for Centrally Extended Two- Dimensional Galilei Algebra and their Lie-Poisson Counterparts

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    All bialgebra structures for centrally extended Galilei algebra are classified. The corresponding Lie-Poisson structures on centrally extended Galilei group are found.Comment: Eq. (11) changed, 15 pages, LaTeX fil
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