77 research outputs found

    Measuring the Relative Strong Phase in D0→K∗+K−D^0 \to K^{*+} K^- and D0→K∗−K+D^0 \to K^{*-} K^+ Decays

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    In a recently suggested method for measuring the weak phase γ\gamma in B±→K±(KK∗)DB^\pm \to K^\pm (KK^*)_D decays, the relative strong phase δD\delta_D in D0→K∗+K−D^0 \to K^{*+} K^- and D0→K∗−K+D^0 \to K^{*-} K^+ decays (equivalently, in D0→K∗+K−D^0 \to K^{*+} K^- and \od \to K^{*+} K^-) plays a role. It is shown how a study of the Dalitz plot in D0→K+K−π0D^0 \to K^+ K^- \pi^0 can yield information on this phase, and the size of the data sample which would give a useful measurement is estimated.Comment: 13 pages, latex, 5 figures, submitted to Phys. Rev. D. Appendix and some text on additional resonant contributions adde

    The K^*_0(800) scalar resonance from Roy-Steiner representations of pi K scattering

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    We discuss the existence of the light scalar meson K^*_0(800) (also called kappa) in a rigorous way, by showing the presence of a pole in the pi K --> pi K amplitude on the second Riemann sheet. For this purpose, we study the domain of validity of two classes of Roy-Steiner representations in the complex energy plane. We prove that one of them is valid in a region sufficiently broad in the imaginary direction. From this representation, we compute the l=0 partial wave in the complex plane with neither additional approximation nor model dependence, relying only on experimental data. A scalar resonance with strangeness S=1 is found with the following mass and width: E_kappa = 658 \pm 13 MeV and Gamma_kappa = 557 \pm 24 MeV.Comment: 16 pages, 8 figures. Domain of validity of a Roy-Steiner representation corrected and enlarged, and features of the K^*_0(800) pole discussed in more details. Conclusions unchange

    Chaos assisted tunnelling with cold atoms

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    In the context of quantum chaos, both theory and numerical analysis predict large fluctuations of the tunnelling transition probabilities when irregular dynamics is present at the classical level. We consider here the non-dissipative quantum evolution of cold atoms trapped in a time-dependent modulated periodic potential generated by two laser beams. We give some precise guidelines for the observation of chaos assisted tunnelling between invariant phase space structures paired by time-reversal symmetry.Comment: submitted to Phys. Rev. E ; 16 pages, 13 figures; figures of better quality can be found at http://www.phys.univ-tours.fr/~mouchet

    Pregnancy outcomes and birth defects from an antiretroviral drug safety study of women in South Africa and Zambia

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    OBJECTIVE : To evaluate the safety of combination antiretroviral therapy (ART) in conception and pregnancy in different health systems. DESIGN : A pilot ART registry to measure the prevalence of birth defects and adverse pregnancy outcomes in South Africa and Zambia. METHODS : HIV-infected pregnant women on ART prior to conception were enrolled until delivery, and their infants were followed until 1 year old. RESULTS : Between October 2010 and April 2011, 600 women were enrolled. The median CD4þ cell count at study enrollment was lower in South Africa than Zambia (320 vs. 430 cells/ml; P<0.01). The most common antiretroviral drugs at the time of conception included stavudine, lamivudine, and nevirapine. There were 16 abortions (2.7%), 1 ectopic pregnancy (0.2%), 12 (2.0%) stillbirths, and 571 (95.2%) live infants. Deliveries were more often preterm (29.7 vs. 18.4%; P¼0.01) and the infants had lower birth weights (2900 vs. 2995 g; P¼0.11) in Zambia compared to South Africa. Thirty-six infants had birth defects: 13 major and 23 minor. There were more major anomalies detected in South Africa and more minor ones in Zambia. No neonatal deaths were attributed to congenital birth defects. CONCLUSIONS : An Africa-specific, multi-site antiretroviral drug safety registry for pregnant women is feasible. Different prevalence for preterm delivery, delivery mode, and birth defect types between women on preconception ART in South Africa and Zambia highlight the potential impact of health systems on pregnancy outcomes. As countries establish ART drug safety registries, documenting health facility limitations may be as essential as the specific ART details.President’s Emergency Plan for AIDS Relief (PEPFAR) through the Centers for Disease Control and Prevention (CDC) under the terms of Cooperative Agreements U62/CCU123541, 3U2GGH000175–01W1, and 3U2GPS001421.http://www.lww.com/product/?0269-9370hb201

    B cell activity is impaired in human and mouse obesity and is responsive to an essential fatty acid upon murine influenza infection

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    Obesity is associated with increased risk for infections and poor responses to vaccinations, which may be due to compromised B cell function. However, there is limited information about the influence of obesity on B cell function and underlying factors that modulate B cell responses. Therefore, we studied B cell cytokine secretion and/or Ab production across obesity models. In obese humans, B cell IL-6 secretion was lowered and IgM levels were elevated upon ex vivo anti-BCR/TLR9 stimulation. In murine obesity induced by a high fat diet, ex vivo IgM and IgG were elevated with unstimulated B cells. Furthermore, the high fat diet lowered bone marrow B cell frequency accompanied by diminished transcripts of early lymphoid commitment markers. Murine B cell responses were subsequently investigated upon influenza A/Puerto Rico/8/34 infection using a Western diet model in the absence or presence of docosahexaenoic acid (DHA). DHA, an essential fatty acid with immunomodulatory properties, was tested because its plasma levels are lowered in obesity. Relative to controls, mice consuming theWestern diet had diminished Ab titers whereas theWestern diet plus DHA improved titers. Mechanistically, DHA did not directly target B cells to elevate Ab levels. Instead, DHA increased the concentration of the downstream specialized proresolving lipid mediators (SPMs) 14-hydroxydocosahexaenoic acid, 17-hydroxydocosahexaenoic acid, and protectin DX. All three SPMs were found to be effective in elevating murine Ab levels upon influenza infection. Collectively, the results demonstrate that B cell responses are impaired across human and mouse obesity models and show that essential fatty acid status is a factor influencing humoral immunity, potentially through an SPM-mediated mechanism

    "Tomography" of the cluster structure of light nuclei via relativistic dissociation

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    These lecture notes present the capabilities of relativistic nuclear physics for the development of the physics of nuclear clusters. Nuclear track emulsion continues to be an effective technique for pilot studies that allows one, in particular, to study the cluster dissociation of a wide variety of light relativistic nuclei within a common approach. Despite the fact that the capabilities of the relativistic fragmentation for the study of nuclear clustering were recognized quite a long time ago, electronic experiments have not been able to come closer to an integrated analysis of ensembles of relativistic fragments. The continued pause in the investigation of the "fine" structure of relativistic fragmentation has led to resumption of regular exposures of nuclear emulsions in beams of light nuclei produced for the first time at the Nuclotron of the Joint Institute for Nuclear Research (JINR, Dubna). To date, an analysis of the peripheral interactions of relativistic isotopes of beryllium, boron, carbon and nitrogen, including radioactive ones, with nuclei of the emulsion composition, has been performed, which allows the clustering pattern to be presented for a whole family of light nuclei.Comment: ISBN 978-3-319-01076-2. 55 pages, 28 figure

    Approximate Bisimulations for Sodium Channel Dynamics

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    Abstract. This paper shows that, in the context of the Iyer et al. 67-variable cardiac myocycte model (IMW), it is possible to replace the detailed 13-state continuous-time MDP model of the sodium-channel dy-namics, with a much simpler Hodgkin-Huxley (HH)-like two-state sodium-channel model, while only incurring a bounded approximation error. The technical basis for this result is the construction of an approximate bisim-ulation between the HH and IMW channel models, both of which are input-controlled (voltage in this case) continuous-time Markov chains. The construction of the appropriate approximate bisimulation, as well as the overall result regarding the behavior of this modified IMW model, in-volves: (1) The identification of the voltage-dependent parameters of the m and h gates in the HH-type channel, based on the observations of the IMW channel. (2) Proving that the distance between observations of the two channels never exceeds a given error. (3) Exploring the sensitivity of the overall IMW model to the HH-type sodium-channel approximation. Our extensive simulation results experimentally validate our findings, for varying IMW-type input stimuli

    Management and treatment of children, young people and adults with systemic lupus erythematosus: British Society for Rheumatology guideline scope

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    The objective of this guideline is to provide up-to-date, evidence-based recommendations for the management of SLE that builds upon the existing treatment guideline for adults living with SLE published in 2017. This will incorporate advances in the assessment, diagnosis, monitoring, non-pharmacological and pharmacological management of SLE. General approaches to management as well as organ-specific treatment, including lupus nephritis and cutaneous lupus, will be covered. This will be the first guideline in SLE using a whole life course approach from childhood through adolescence and adulthood. The guideline will be developed with people with SLE as an important target audience in addition to healthcare professionals. It will include guidance related to emerging approved therapies and account for National Institute for Health and Care Excellence Technology Appraisals, National Health Service England clinical commissioning policies and national guidance relevant to SLE. The guideline will be developed using the methods and rigorous processes outlined in ‘Creating Clinical Guidelines: Our Protocol’ by the British Society for Rheumatology

    Input impedance and output impedance of feedback amplifiers

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