392 research outputs found

    Quantum Symmetries and Strong Haagerup Inequalities

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    In this paper, we consider families of operators {xr}rβˆˆΞ›\{x_r\}_{r \in \Lambda} in a tracial Cβˆ—^\ast-probability space (A,Ο•)(\mathcal A, \phi), whose joint βˆ—\ast-distribution is invariant under free complexification and the action of the hyperoctahedral quantum groups {Hn+}n∈N\{H_n^+\}_{n \in \N}. We prove a strong form of Haagerup's inequality for the non-self-adjoint operator algebra B\mathcal B generated by {xr}rβˆˆΞ›\{x_r\}_{r \in \Lambda}, which generalizes the strong Haagerup inequalities for βˆ—\ast-free R-diagonal families obtained by Kemp-Speicher \cite{KeSp}. As an application of our result, we show that B\mathcal B always has the metric approximation property (MAP). We also apply our techniques to study the reduced Cβˆ—^\ast-algebra of the free unitary quantum group Un+U_n^+. We show that the non-self-adjoint subalgebra Bn\mathcal B_n generated by the matrix elements of the fundamental corepresentation of Un+U_n^+ has the MAP. Additionally, we prove a strong Haagerup inequality for Bn\mathcal B_n, which improves on the estimates given by Vergnioux's property RD \cite{Ve}

    Phenotypic Studies of Natural Killer Cell Subsets in Human Transporter Associated with Antigen Processing Deficiency

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    Peripheral blood natural killer (NK) cells from patients with transporter associated with antigen processing (TAP) deficiency are hyporesponsive. The mechanism of this defect is unknown, but the phenotype of TAP-deficient NK cells is almost normal. However, we noticed a high percentage of CD56bright cells among total NK cells from two patients. We further investigated TAP-deficient NK cells in these patients and compared them to NK cells from two other TAP-deficient patients with no clinical symptoms and to individuals with chronic inflammatory diseases other than TAP deficiency (chronic lung diseases or vasculitis). Peripheral blood mononuclear cells isolated from venous blood were stained with fluorochrome-conjugated antibodies and the phenotype of NK cells was analyzed by flow cytometry. In addition, 51Chromium release assays were performed to assess the cytotoxic activity of NK cells. In the symptomatic patients, CD56bright NK cells represented 28% and 45%, respectively, of all NK cells (higher than in healthy donors). The patients also displayed a higher percentage of CD56dimCD16βˆ’ NK cells than controls. Interestingly, this unusual NK cell subtype distribution was not found in the two asymptomatic TAP-deficient cases, but was instead present in several of the other patients. Over-expression of the inhibitory receptor CD94/NKG2A by TAP-deficient NK cells was confirmed and extended to the inhibitory receptor ILT2 (CD85j). These inhibitory receptors were not involved in regulating the cytotoxicity of TAP-deficient NK cells. We conclude that expansion of the CD56bright NK cell subtype in peripheral blood is not a hallmark of TAP deficiency, but can be found in other diseases as well. This might reflect a reaction of the immune system to pathologic conditions. It could be interesting to investigate the relative distribution of NK cell subsets in various respiratory and autoimmune diseases

    The approach to thermalization in the classical phi^4 theory in 1+1 dimensions: energy cascades and universal scaling

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    We study the dynamics of thermalization and the approach to equilibrium in the classical phi^4 theory in 1+1 spacetime dimensions. At thermal equilibrium we exploit the equivalence between the classical canonical averages and transfer matrix quantum traces of the anharmonic oscillator to obtain exact results for the temperature dependence of several observables, which provide a set of criteria for thermalization. We find that the Hartree approximation is remarkably accurate in equilibrium. The non-equilibrium dynamics is studied by numerically solving the equations of motion in light-cone coordinates for a broad range of initial conditions and energy densities.The time evolution is described by several stages with a cascade of energy towards the ultraviolet. After a transient stage, the spatio-temporal gradient terms become larger than the nonlinear term and a stage of universal cascade emerges.This cascade starts at a time scale t_0 independent of the initial conditions (except for very low energy density). Here the power spectra feature universal scaling behavior and the front of the cascade k(t) grows as a power law k(t) sim t^alpha with alpha lesssim 0.25. The wake behind the cascade is described as a state of Local Thermodynamic Equilibrium (LTE) with all correlations being determined by the equilibrium functional form with an effective time dependent temperatureTeff(t) which slowly decreases as sim t^{-alpha}.Two well separated time scales emerge while Teff(t) varies slowly, the wavectors in the wake with k < k(t) attain LTE on much shorter time scales.This universal scaling stage ends when the front of the cascade reaches the cutoff at a time t_1 sim a^{-1/alpha}. Virialization starts to set much earlier than LTE. We find that strict thermalization is achieved only for an infinite time scale.Comment: relevance for quantum field theory discussed providing validity criteria. To appear in Phys. Rev.

    Out-of-equilibrium evolution of quantum fields in the hybrid model with quantum back reaction

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    The hybrid model with a scalar "inflaton" field coupled to a "Higgs" field with a broken symmetry potential is one of the promising models for inflation and (p)reheating after inflation. We consider the nonequilibrium evolution of the quantum fields of this model with quantum back reaction in the Hartree approximation, in particular the transition of the Higgs field from the metastable "false vacuum" to the broken symmetry phase. We have performed the renormalization of the equations of motion, of the gap equations and of the energy density, using dimensional regularization. We study the influence of the back reaction on the evolution of the classical fields and of the quantum fluctuations. We observe that back reaction plays an important role over a wide range of parameters. Some implications of our investigation for the preheating stage after cosmic inflation are presented.Comment: 35 pages, 16 eps figures, revtex4; v2: typos corrected and references added, accepted for publication in Physical Review

    The Use and Effectiveness of an Online Diagnostic Support System for Blood Film Interpretation: Comparative Observational Study

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    Background The recognition and interpretation of abnormal blood cell morphology is often the first step in diagnosing underlying serious systemic illness or leukemia. Supporting the staff who interpret blood film morphology is therefore essential for a safe laboratory service. This paper describes an open-access, web-based decision support tool, developed by the authors to support morphological diagnosis, arising from earlier studies identifying mechanisms of error in blood film reporting. The effectiveness of this intervention was assessed using the unique resource offered by the online digital morphology Continuing Professional Development scheme (DM scheme) offered by the UK National External Quality Assessment Service for Haematology, with more than 3000 registered users. This allowed the effectiveness of decision support to be tested within a defined user group, each of whom viewed and interpreted the morphology of identical digital blood films. Objective The primary objective of the study was to test the effectiveness of the decision support system in supporting users to identify and interpret abnormal morphological features. The secondary objective was to determine the pattern and frequency of use of the system for different case types, and to determine how users perceived the support in terms of their confidence in decision-making. Methods This was a comparative study of identical blood films evaluated either with or without decision support. Selected earlier cases from the DM scheme were rereleased as new cases but with decision support made available; this allowed a comparison of data sets for identical cases with or without decision support. To address the primary objectives, the study used quantitative evaluation and statistical comparisons of the identification and interpretation of morphological features between the two different case releases. To address the secondary objective, the use of decision support was assessed using web analytical tools, while a questionnaire was used to assess user perceptions of the system. Results Cases evaluated with the aid of decision support had significantly improved accuracy of identification for relevant morphological features (mean improvement 9.8%) and the interpretation of those features (mean improvement 11%). The improvement was particularly significant for cases with higher complexity or for rarer diagnoses. Analysis of website usage demonstrated a high frequency of access for web pages relevant to each case (mean 9298 for each case, range 2661-24,276). Users reported that the decision support website increased their confidence for feature identification (4.8/5) and interpretation (4.3/5), both within the context of training (4.6/5) and also in their wider laboratory practice (4.4/5). Conclusions The findings of this study demonstrate that directed online decision support for blood morphology evaluation improves accuracy and confidence in the context of educational evaluation of digital films, with effectiveness potentially extending to wider laboratory use. </jats:sec

    Repeated ovarian stimulation with corifollitropin alfa in patients in a GnRH antagonist protocol: no concern for immunogenicity

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    BACKGROUND One injection of corifollitropin alfa replaces the first seven daily FSH injections in controlled ovarian stimulation (COS) cycles. Repeated treatment with therapeutic proteins may cause immune responses or hypersensitivity reactions. We assessed the immunogenicity and safety of corifollitropin alfa treatment in up to three COS cycles. METHODS In this multicentre, phase III uncontrolled trial, patients (>60 kg) started treatment with one injection of 150 Β΅g corifollitropin alfa on cycle Day 2 or 3 of menses and 0.25 mg ganielix on stimulation Day 5 or 6. Primary outcome measures were antibody formation against corifollitropin alfa (using highly sensitive radioimmunoprecipitation assay), hypersensitivity reactions, local tolerance and adverse events (AEs). RESULTS First, second and third COS cycles were started by 682, 375 and 198 patients, respectively. No clinically relevant immunogenicity or drug-related hypersensitivity was observed. For 192 patients undergoing their third cycle a post-treatment blood sample was negative in the anti-corifollitropin antibody assay, resulting in an upper limit of the one-sided 95% confidence interval (CI) of 1.5%. Most frequent AEs were procedural pain (17.7%, 95% CI: 14.9–20.8%), headache (9.1%, 95% CI: 7.0–11.5%) and pelvic pain (7.6%, 95% CI: 5.7–9.9%). Cumulative ongoing pregnancy rate after three cycles, including frozen-thawed embryo transfer cycles and spontaneous pregnancies, was 61% (95% CI: 56–65%) after censoring for patients who discontinued. CONCLUSIONS Treatment with corifollitropin alfa can safely and effectively initiate and sustain ovarian stimulation during the first 7 days of COS in normal responder patients undergoing up to three treatment cycles, without concerns of immunogenicity.Robert J. Norman, Fernando Zegers-Hochschild, Bruno S. Salle, Jolanda Elbers, Esther Heijnen, Maya Marintcheva-Petrova, and Bernadette Mannaerts for the Trust Investigator

    Formation of topological defects in gauge field theories

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    When a symmetry gets spontaneously broken in a phase transition, topological defects are typically formed. The theoretical picture of how this happens in a breakdown of a global symmetry, the Kibble-Zurek mechanism, is well established and has been tested in various condensed matter experiments. However, from the viewpoint of particle physics and cosmology, gauge field theories are more relevant than global theories. In recent years, there have been significant advances in the theory of defect formation in gauge field theories, which make precise predictions possible, and in experimental techniques that can be used to test these predictions in superconductor experiments. This opens up the possibility of carrying out relatively simple and controlled experiments, in which the non-equilibrium phase transition dynamics of gauge field theories can be studied. This will have a significant impact on our understanding of phase transitions in the early universe and in heavy ion collider experiments. In this paper, I review the current status of the theory and the experiments in which it can be tested.Comment: Review article, 43 pages, 7 figures. Minor changes, some references added. Final version to appear in IJMP

    Defending the genome from the enemy within:mechanisms of retrotransposon suppression in the mouse germline

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    The viability of any species requires that the genome is kept stable as it is transmitted from generation to generation by the germ cells. One of the challenges to transgenerational genome stability is the potential mutagenic activity of transposable genetic elements, particularly retrotransposons. There are many different types of retrotransposon in mammalian genomes, and these target different points in germline development to amplify and integrate into new genomic locations. Germ cells, and their pluripotent developmental precursors, have evolved a variety of genome defence mechanisms that suppress retrotransposon activity and maintain genome stability across the generations. Here, we review recent advances in understanding how retrotransposon activity is suppressed in the mammalian germline, how genes involved in germline genome defence mechanisms are regulated, and the consequences of mutating these genome defence genes for the developing germline
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