3,449 research outputs found

    On invariants of graphs related to quantum sl(2)\mathfrak{sl}(2) at roots of unity

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    We show how to define invariants of graphs related to quantum sl(2)\mathfrak{sl}(2) when the graph has more then one connected component and components are colored by blocks of representations with zero quantum dimensions

    Modified 6j-symbols and 3-manifold invariants

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    37 pages, 16 figuresInternational audienceWe show that the renormalized quantum invariants of links and graphs in the 3-sphere, derived from tensor categories in ["Modified quantum dimensions and re-normalized link invariants", arXiv:0711.4229] lead to modified 6j-symbols and to new state sum 3-manifold invariants. We give examples of categories such that the associated standard Turaev-Viro 3-manifold invariants vanish but the secondary invariants may be non-zero. The categories in these examples are pivotal categories which are neither ribbon nor semi-simple and have an infinite number of simple objects

    Relations between some invariants of algebraic varieties in positive characteristic

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    We discuss relations between certain invariants of varieties in positive characteristic, like the a-number and the height of the Artin-Mazur formal group. We calculate the a-number for Fermat surfacesComment: 13 page

    Tetrahedral forms in monoidal categories and 3-manifold invariants

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    We introduce systems of objects and operators in linear monoidal categories called Ψ^\hat{\Psi}-systems. A Ψ^\hat{\Psi}-system satisfying several additional assumptions gives rise to a topological invariant of triples (a closed oriented 3-manifold MM, a principal bundle over MM, a link in MM). This construction generalizes the quantum dilogarithmic invariant of links appearing in the original formulation of the volume conjecture. We conjecture that all quantum groups at odd roots of unity give rise to Ψ^\hat{\Psi}-systems and we verify this conjecture in the case of the Borel subalgebra of quantum sl2_{2}

    Non semi-simple sl(2) quantum invariants, spin case

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    Invariants of 3-manifolds from a non semi-simple category of modules over a version of quantum sl(2) were obtained by the last three authors in [arXiv:1404.7289]. In their construction the quantum parameter qq is a root of unity of order 2r2r where r>1r>1 is odd or congruent to 22 modulo 44. In this paper we consider the remaining cases where rr is congruent to zero modulo 44 and produce invariants of 33-manifolds with colored links, equipped with generalized spin structure. For a given 33-manifold MM, the relevant generalized spin structures are (non canonically) parametrized by H1(M;C/2Z)H^1(M;\mathbb C/2\mathbb Z).Comment: 13 pages, 16 figure

    Estimation of Relative Abundance of Recreationally Important Finfish in the Virginia Portion of Chesapeake Bay: Annual Progress Report 1994-1995

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    Annual indices of juvenile abundance have been generated from trawl survey data for several species of key recreational importance in the Virginia portion of Chesapeake Bay (spot, croaker, weakfish, summer flounder, black sea bass and striped bass, white and channel catfish) and four species of secondary importance (scup, white perch, northern puffer, and silver perch) for the period 1988-1995. No species has shown a continuous trend during the seven year period, although several species have revealed declines (spot, scup y-o-y white perch, northern puffer) or increases (Atlantic croaker and striped bass) in recent years. Spot has shown the largest decline from a high geometric mean catch per trawl of 68 ( 1988) to a low ( 1992) of 2, stabilizing near 9 the past two years. Atlantic croaker showed the greatest variability between years, with the 1989 index of 65 being 4 to 7 times higher than that seen in the other six years. The weakfish estimate declined in 1994 after three years of near constant levels. Striped bass estimates declined significantly in 1994 (1.07 geometric mean catch per trawl), after reaching near record levels in 1993 (3.3). Juvenile summer flounder values increased five fold, reversing a two year trend of historic low values. Black sea bass and scup juvenile recruitment to lower Chesapeake Bay showed no evidence of a trend over the seven year period. The age 1 + values for the catfish species remained relatively stable while y-o-y estimates varies much more. Northern puffer has exhibited a near continuous downward trend since the start of the expanded survey in 1988. Silver perch are characterized by periods of very low abundance followed by several years of high catch rates

    Probing lepton flavour violation in νμ+Nτ+...\nu_{\mu} + N \to \tau + ... scattering and μtau\mu \to tau conversion on nucleons

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    We study lepton flavour-violating interactions which could result in the τ\tau-lepton production in the νμN\nu_{\mu}N scattering or in μτ\mu \to \tau conversion on nucleons at high energies. Phenomenological bounds on the strength of τˉνμqˉq\bar{\tau}\nu_{\mu}\bar{q}q^{'} interactions are extracted from the combined result of the NOMAD and CHORUS experiments on searching for νμντ\nu_{\mu} - \nu_{\tau} oscillations. Some of these bounds supersede limits from rare decays. We also propose a ``missing energy'' type experiment searching for μτ\mu - \tau conversion on nucleons. The experiment can be performed at a present accelerator or at a future neutrino factory.Comment: 13 pages, 4 figure

    Genre Interference in the Process of Foreign Language Speaking Training

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    This article is devoted to a study of speech genre competence formation in technical students studying foreign language (English or Russian as a foreign). Correlations of terms of speech genre theory and types of speech genre classification are the subject of this work; the need to form speech genre competence as a component of communicative competence during the educational process is substantiated. The authors suppose that during the process of learning a foreign language, processes not only of phonetic, grammar and lexical, but also of genre interference are observed. On the basis of a "genre" experiment, material types of deviations from genre forms were classified, a hypothesis for the reasons for deviation was developed, comparison study of speech product in foreign (non-native) and native language, was carried out. Conclusion on significant interfering influence of native language on formation of speech genre competence of secondary linguistic identity was drawn

    The effectiveness of interventions in workplace health promotion as to maintain the working capacity of health care personal

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    Background: The increasing proportion of elderly people with respective care requirements and within the total population stands against aging personnel and staff reduction in the field of health care where employees are exposed to high load factors. Health promotion interventions may be a possibility to improve work situations and behavior. Methods: A systematic literature search is conducted in 32 databases limited to English and German publications since 1990. Moreover, internet-searches are performed and the reference lists of identified articles are scanned. The selection of literature was done by two reviewers independently according to inclusion and exclusion criteria. Data extraction and tables of evidence are verified by a second expert just like the assessment of risk of bias by means of the Cochrane Collaboration’s tool. Results: We identified eleven intervention studies and two systematic reviews. There were three randomized controlled trials (RCT) and one controlled trial without randomization (CCT) on the improvement of physical health, four RCT and two CCT on the improvement of psychological health and one RCT on both. Study duration ranged from four weeks to two years and the number of participants included from 20 to 345, with a median of 56. Interventions and populations were predominantly heterogeneous. In three studies intervention for the improvement of physical health resulted in less complaints and increased strength and flexibility with statistically significant differences between groups. Regarding psychological health interventions lead to significantly decreased intake of analgesics, better stress management, coping with workload, communication skills and advanced training. Discussion: Taking into consideration the small to very small sample sizes, other methodological flaws like a high potential of bias and poor quality of reporting the validity of the results has to be considered as limited. Due to the heterogeneity of health interventions, study populations with differing job specializations and different lengths of study durations and follow-up periods, the comparison of results would not make sense. Conclusions: Further research is necessary with larger sample sizes, with a sufficient study duration and follow-up, with a lower risk of bias, by considering of relevant quality criteria and with better reporting in publications
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