10,912 research outputs found

    Lax Operator for the Quantised Orthosymplectic Superalgebra U_q[osp(2|n)]

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    Each quantum superalgebra is a quasi-triangular Hopf superalgebra, so contains a \textit{universal RR-matrix} in the tensor product algebra which satisfies the Yang-Baxter equation. Applying the vector representation π\pi, which acts on the vector module VV, to one side of a universal RR-matrix gives a Lax operator. In this paper a Lax operator is constructed for the CC-type quantum superalgebras Uq[osp(2∣n)]U_q[osp(2|n)]. This can in turn be used to find a solution to the Yang-Baxter equation acting on V⊗V⊗WV \otimes V \otimes W where WW is an arbitrary Uq[osp(2∣n)]U_q[osp(2|n)] module. The case W=VW=V is included here as an example.Comment: 15 page

    Generalised Perk--Schultz models: solutions of the Yang-Baxter equation associated with quantised orthosymplectic superalgebras

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    The Perk--Schultz model may be expressed in terms of the solution of the Yang--Baxter equation associated with the fundamental representation of the untwisted affine extension of the general linear quantum superalgebra Uq[sl(m∣n)]U_q[sl(m|n)], with a multiparametric co-product action as given by Reshetikhin. Here we present analogous explicit expressions for solutions of the Yang-Baxter equation associated with the fundamental representations of the twisted and untwisted affine extensions of the orthosymplectic quantum superalgebras Uq[osp(m∣n)]U_q[osp(m|n)]. In this manner we obtain generalisations of the Perk--Schultz model.Comment: 10 pages, 2 figure

    Supersymmetric t-J Gaudin Models and KZ Equations

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    Supersymmetric t-J Gaudin models with both periodic and open boundary conditions are constructed and diagonalized by means of the algebraic Bethe ansatz method. Off-shell Bethe ansatz equations of the Gaudin systems are derived, and used to construct and solve the KZ equations associated with sl(2∣1)(1)sl(2|1)^{(1)} superalgebra.Comment: LaTex 21 page

    Simple model of self-organized biological evolution as completely integrable dissipative system

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    The Bak-Sneppen model of self-organized biological evolution of an infinite ecosystem of randomly interacting species is represented in terms of an infinite set of variables which can be considered as an analog to the set of integrals of motion of completely integrable system. Each of this variables remains to be constant but its influence on the evolution process is restricted in time and after definite moment its value is excluded from description of the system dynamics.Comment: LaTeX, 7 page

    Disciplinary processes and the management of poor performance among UK nurses: bad apple or systemic failure? A scoping study

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    The rise of managerialism within healthcare systems has been noted globally. This paper uses the findings of a scoping study to investigate the management of poor performance among nurses and midwives in the United Kingdom within this context. The management of poor performance among clinicians in the NHS has been seen as a significant policy problem. There has been a profound shift in the distribution of power between professional and managerial groups in many health systems globally. We examined literature published between 2000 and 10 to explore aspects of poor performance and its management. We used Web of Science, CINAHL, MEDLINE, British Nursing Index, HMIC, Cochrane Library and PubMed. Empirical data are limited but indicate that nurses and midwives are the clinical groups most likely to be suspended and that poor performance is often represented as an individual deficit. A focus on the individual as a source of trouble can serve as a distraction from more complex systematic problems

    Microlensing Characterization of Wide-Separation Planets

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    With their excellent photometric precision and dramatic increase in monitoring frequency, future microlensing survey experiments are expected to be sensitive to very short time-scale, isolated events caused by free-floating and wide-separation planets with mass as low as a few lunar masses. We estimate the probability of measuring the Einstein radius \theta_E for bound and free-floating planets. We carry out detailed simulations of the planetary events expected in next-generation surveys and estimate the resulting uncertainty in \theta_E for these events. We show that, for main-sequence sources and Jupiter-mass planets, the caustic structure of wide-separation planets with projected separations of < 20 AU substantially increases the probability of measuring the dimensionless source size and thus determining \theta_E compared to the case of unbound planets. In this limit where the source is much smaller than the caustic, the effective cross-section to measure \theta_E to 10% is ~25% larger than the full width of the caustic. Measurement of the lens parallax is possible for low-mass planetary events by combined observations from the ground and a satellite located in an L2 orbit; this would complete the mass measurements for such wide-separation planets. Finally, short-duration events caused by bound planets can be routinely distinguished from those caused by free-floating planets for planet-star separations < 20 AU from either the deviations due to the planetary caustic or (more often) the low-amplitude bump from the magnification due to the parent star.Comment: 10 pages including 7 figures. ApJ, in pres

    The Credit Union Industry in the Financial Services Marketplace of the 21st Century

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    The credit union industry has been consolidating for more than a quarter century, as well as broadening and diversifying its product and service offerings. In this period the operating performance and internal structure of the industry has been evolving in a number of ways. This study examines the changing chartering patterns of credit unions between state and federal. The number of credit unions, the number of members, and the assets held by credit unions in each of these categories have been growing at different rates. We examine these patterns of development and project the expected changes in structure through the year 2010

    Credit Union Industry Consolidation in the 1990s

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    The financial services industry has been consolidating for more than two decades. This study examines the extent and affects of the deregulation movement on the credit union industry. It identifies a number of operational factors that have contributed to growth of the average size credit union in the 1990s and benefits to members that have resulted from this consolidation trend

    Cdk1-dependent phosphoinhibition of a formin-F-BAR interaction opposes cytokinetic contractile ring formation

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    © 2018 Willet et al. In Schizosaccharomyces pombe, cytokinesis requires the assembly and constriction of an actomyosin-based contractile ring (CR). A single essential formin, Cdc12, localizes to the cell middle upon mitotic onset and nucleates the F-actin of the CR. Cdc12 medial recruitment is mediated in part by its direct binding to the F-BAR scaffold Cdc15. Given that Cdc12 is hyperphosphorylated in M phase, we explored whether Cdc12 phosphoregulation impacts its association with Cdc15 during mitosis. We found that Cdk1, a major mitotic kinase, phosphorylates Cdc12 on six N-terminal residues near the Cdc15-binding site, and phosphorylation on these sites inhibits its interaction with the Cdc15 F-BAR domain. Consistent with this finding, a cdc12 mutant with all six Cdk1 sites changed to phosphomimetic residues (cdc12-6D) displays phenotypes similar to cdc12-P31A, in which the Cdc15-binding motif is disrupted; both show reduced Cdc12 at the CR and delayed CR formation. Together, these results indicate that Cdk1 phosphorylation of formin Cdc12 antagonizes its interaction with Cdc15 and thereby opposes Cdc12\u27s CR localization. These results are consistent with a general role of Cdk1 in inhibiting cytokinesis until chromosome segregation is complete

    The importance of culture in predicting environmental behavior in middle school students on Hawai‘i island

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    Researchers have investigated the factors that influence environmental behavior for decades. Two often-investigated phenomena, connectedness to nature and self-efficacy, often correlate with environmental behavior, yet researchers rarely analyze those correlations along with underlying cultural factors. We suggest that this is a substantial oversight and hypothesize that cultural factors affect environmental behavior, particularly through an interplay with the connectedness to nature and self-efficacy constructs. To test this hypothesis, we surveyed eighth-grade students on the island of Hawai‘i. The instrument included items to assess connectedness to nature and self-efficacy (both frequently measured in environmental behavior studies) and multiple measures of behavior. Most of the behavior measures are commonly used in studies of environmental behavior, and one was developed in collaboration with local partners to reflect more culturally specific modes of environmental behavior. With those partners, we also developed a construct reflecting the relevance of local culture. We explored the relative influence of the more commonly investigated constructs (connectedness to nature, behavioral variables) along with the newer construct (cultural relevance). We found that, when we took those considerations into account, cultural relevance significantly predicted connectedness to nature, self-efficacy, and a commonly used behavioral measure. Our results thus suggest that many models of environmental behavior may be misspecified when they omit critical culture- and ethnicity-related factors. This may be particularly important in contexts with high cultural, racial, and ethnic diversity or in contexts where mainstream Western environmental approaches are non-dominant. Our results emphasize the importance of addressing ethnicity and culture in environmental thought and action
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