832 research outputs found

    Tests of Lorentz violation in muon antineutrino to electron antineutrino oscillations

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    A recently developed Standard-Model Extension (SME) formalism for neutrino oscillations that includes Lorentz and CPT violation is used to analyze the sidereal time variation of the neutrino event excess measured by the Liquid Scintillator Neutrino Detector (LSND) experiment. The LSND experiment, performed at Los Alamos National Laboratory, observed an excess, consistent with neutrino oscillations, of νˉe{\bar\nu}_e in a beam of νˉμ{\bar\nu}_\mu. It is determined that the LSND oscillation signal is consistent with no sidereal variation. However, there are several combinations of SME coefficients that describe the LSND data; both with and without sidereal variations. The scale of Lorentz and CPT violation extracted from the LSND data is of order 101910^{-19} GeV for the SME coefficients aLa_L and E×cLE \times c_L. This solution for Lorentz and CPT violating neutrino oscillations may be tested by other short baseline neutrino oscillation experiments, such as the MiniBooNE experiment.Comment: 10 pages, 10 figures, 2 tables, uses revtex4 replaced with version to be published in Physical Review D, 11 pages, 11 figures, 2 tables, uses revtex

    Connected components of spaces of Morse functions with fixed critical points

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    Let MM be a smooth closed orientable surface and F=Fp,q,rF=F_{p,q,r} be the space of Morse functions on MM having exactly pp critical points of local minima, q1q\ge1 saddle critical points, and rr critical points of local maxima, moreover all the points are fixed. Let FfF_f be the connected component of a function fFf\in F in FF. By means of the winding number introduced by Reinhart (1960), a surjection π0(F)Zp+r1\pi_0(F)\to{\mathbb Z}^{p+r-1} is constructed. In particular, π0(F)=|\pi_0(F)|=\infty, and the Dehn twist about the boundary of any disk containing exactly two critical points, exactly one of which is a saddle point, does not preserve FfF_f. Let D\mathscr D be the group of orientation preserving diffeomorphisms of MM leaving fixed the critical points, D0{\mathscr D}^0 be the connected component of idM{\rm id}_M in D\mathscr D, and DfD{\mathscr D}_f\subset{\mathscr D} the set of diffeomorphisms preserving FfF_f. Let Hf{\mathscr H}_f be the subgroup of Df{\mathscr D}_f generated by D0{\mathscr D}^0 and all diffeomorphisms hDh\in{\mathscr D} which preserve some functions f1Fff_1\in F_f, and let Hfabs{\mathscr H}_f^{\rm abs} be its subgroup generated D0{\mathscr D}^0 and the Dehn twists about the components of level curves of functions f1Fff_1\in F_f. We prove that HfabsDf{\mathscr H}_f^{\rm abs}\subsetneq{\mathscr D}_f if q2q\ge2, and construct an epimorphism Df/HfabsZ2q1{\mathscr D}_f/{\mathscr H}_f^{\rm abs}\to{\mathbb Z}_2^{q-1}, by means of the winding number. A finite polyhedral complex K=Kp,q,rK=K_{p,q,r} associated to the space FF is defined. An epimorphism μ:π1(K)Df/Hf\mu:\pi_1(K)\to{\mathscr D}_f/{\mathscr H}_f and finite generating sets for the groups Df/D0{\mathscr D}_f/{\mathscr D}^0 and Df/Hf{\mathscr D}_f/{\mathscr H}_f in terms of the 2-skeleton of the complex KK are constructed.Comment: 12 pages with 2 figures, in Russian, to be published in Vestnik Moskov. Univ., a typo in theorem 1 is correcte

    Search for π0νμνˉμ\pi^0 \to \nu_{\mu}\bar\nu_{\mu} Decay in LSND

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    We observe a net beam-excess of 8.7±6.38.7 \pm 6.3 (stat) ±2.4\pm 2.4 (syst) events, above 160 MeV, resulting from the charged-current reaction of νμ\nu_{\mu} and/or νˉμ\bar\nu_{\mu} on C and H in the LSND detector. No beam related muon background is expected in this energy regime. Within an analysis framework of π0νμνˉμ\pi^0 \to \nu_{\mu}\bar\nu_{\mu}, we set a direct upper limit for this branching ratio of Γ(π0νμνˉμ)/Γ(π0all)<1.6×106\Gamma(\pi^0 \to \nu_\mu \bar\nu_\mu) / \Gamma(\pi^0 \to all) < 1.6 \times 10^{-6} at 90% confidence level.Comment: 4 pages, 4 figure

    Evidence for Neutrino Oscillations from Muon Decay at Rest

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    A search for nu_bar_mu to nu_bar_e oscillations has been conducted at the Los Alamos Meson Physics Facility using nu_bar_mu from mu+ decay at rest. The nu_bar_e are detected via the reaction (nu_bar_e,p) -> (e+,n), correlated with the 2.2 MeV gamma from (n,p) -> (d,gamma). The use of tight cuts to identify e+ events with correlated gamma rays yields 22 events with e+ energy between 36 and 60 MeV and only 4.6 (+/- 0.6) background events. The probability that this excess is due entirely to a statistical fluctuation is 4.1E-08. A chi^2 fit to the entire e+ sample results in a total excess of 51.8 (+18.7) (-16.9) (+/- 8.0) events with e+ energy between 20 and 60 MeV. If attributed to nu_bar_mu -> nu_bar_e oscillations, this corresponds to an oscillation probability (averaged over the experimental energy and spatial acceptance) of 0.0031 (+0.0011) (-0.0010) (+/- 0.0005).Comment: 57 pages, 34 figures, revtex, additional information available at http://nu1.lampf.lanl.gov/~lsnd

    Measurements of Charged Current Reactions of νe\nu_e on 12C^{12}C

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    Charged Current reactions of νe\nu_e on 12C^{12}C have been studied using a μ+\mu^+ decay-at-rest νe\nu_e beam at the Los Alamos Neutron Science Center. The cross section for the exclusive reaction 12C(νe,e)12Ng.s.^{12}C(\nu_e,e^-)^{12}N_{g.s.} was measured to be (8.9±0.3±0.9)×1042(8.9\pm0.3\pm0.9)\times10^{-42} cm2^2. The observed energy dependence of the cross section and angular distribution of the outgoing electron agree well with theoretical expectations. Measurements are also presented for inclusive transitions to 12N^{12}N excited states, 12C(νe,e)12N^{12}C(\nu_e,e^-)^{12}N^* and compared with theoretical expectations. The measured cross section, (4.3±0.4±0.6)×1042(4.3\pm0.4\pm0.6)\times10^{-42} cm2^2, is somewhat lower than previous measurements and than a continuum random phase approximation calculation. It is in better agreement with a recent shell model calculation.Comment: 34 pages, 18 figures, accepted to PRC, replaced with the accepted on

    Measurement of electron-neutrino electron elastic scattering

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    The cross section for the elastic scattering reaction nu_e+e- -> nu_e+e- was measured by the Liquid Scintillator Neutrino Detector using a mu+ decay-at-rest nu_e beam at the Los Alamos Neutron Science Center. The standard model of electroweak physics predicts a large destructive interference between the charge current and neutral current channels for this reaction. The measured cross section, sigma_{nu_e e-}=[10.1 +- 1.1(stat.) +- 1.0(syst.)]x E_{nu_e} (MeV) x 10^{-45} cm^2, agrees well with standard model expectations. The measured value of the interference parameter, I=-1.01 +- 0.13(stat.) +- 0.12(syst.), is in good agreement with the standard model expectation of I^{SM}=-1.09. Limits are placed on neutrino flavor-changing neutral currents. An upper limit on the muon-neutrino magnetic moment of 6.8 x 10^{-10} mu_{Bohr} is obtained using the nu_mu and \bar{nu}_mu fluxes from pi+ and mu+ decay.Comment: 22 pages, 11 figure

    The discursive construction of childhood and youth in AIDS interventions in Lesotho's education sector: Beyond global-local dichotomies

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    This is the post-print version of this article. The definitive, peer-reviewed and edited version of this article is published in Environment and Planning D,Society and Space 28(5) 791 – 810, 2010, available from the link below. Copyright @ 2010 Pion.In southern Africa interventions to halt the spread of AIDS and address its social impacts are commonly targeted at young people, in many cases through the education sector. In Lesotho, education-sector responses to AIDS are the product of negotiation between a range of ‘local’ and ‘global’ actors. Although many interventions are put forward as government policy and implemented by teachers in schools, funding is often provided by bilateral and multilateral donors, and the international ‘AIDS industry’—in the form of UN agencies and international NGOs—sets agendas and makes prescriptions. This paper analyses interviews conducted with policy makers and practitioners in Lesotho and a variety of documents, critically examining the discourses of childhood and youth that are mobilised in producing changes in education policy and practice to address AIDS. Focusing on bursary schemes, life-skills education, and rights-based approaches, the paper concludes that, although dominant ‘global’ discourses are readily identified, they are not simply imported wholesale from the West, but rather are transformed through the organisations and personnel involved in designing and implementing interventions. Nonetheless, the connections through which these discourses are made, and children are subjectified, are central to the power dynamics of neoliberal globalisation. Although the representations of childhood and youth produced through the interventions are hybrid products of local and global discourses, the power relations underlying them are such that they, often unintentionally, serve a neoliberal agenda by depicting young people as individuals in need of saving, of developing personal autonomy, or of exercising individual rights.RGS-IB

    Evidence for nu_mu -> nu_e Neutrino Oscillations from LSND

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    A search for nu_mu -> nu_e oscillations has been conducted with the LSND apparatus at the Los Alamos Meson Physics Facility. Using nu_mu from pi^+ decay in flight, the nu_e appearance is detected via the charged-current reaction C(nu_e,e^-)X. Two independent analyses observe a total of 40 beam-on high-energy electron events (60 < E_e < 200 MeV) consistent with the above signature. This number is significantly above the 21.9 +- 2.1 events expected from the nu_e contamination in the beam and the beam-off background. If interpreted as an oscillation signal, the observed oscillation probability of (2.6 +- 1.0 +- 0.5) x 10^{-3} is consistent with the previously reported nu_mu_bar -> nu_e_bar oscillation evidence from LSND.Comment: 10 pages (LaTeX), 3 figures (PostScript), submitted to Phys.Rev.Lett. Additional information at http://nu1.lampf.lanl.gov/~lsn

    Protocol for a cluster randomised control trial evaluating the efficacy and safety of treatment for latent tuberculosis infection in recent migrants within primary care: the CATAPuLT trial.

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    BACKGROUND: The identification and treatment of LTBI is a key component of the WHO's strategy to eliminate TB. Recent migrants from high TB-incidence countries are recognised to be at risk TB reactivation, and many high-income countries have focused on LTBI screening and treatment programmes for this group. However, migrants are the group least likely to complete the LTBI cascade-of-care. This pragmatic cluster-randomised, parallel group, superiority trial investigates whether a model of care based entirely within a community setting (primary care) will improve treatment completion compared with treatment in specialist TB services (secondary care). METHODS: The CATAPuLT trial (Completion and Acceptability of Treatment Across Primary Care and the community for Latent Tuberculosis) randomised 34 general practices in London, England, to evaluate the efficacy and safety of treatment for LBTI in recent migrants within primary care. GP practices were randomised to either provide management for LTBI entirely within primary care (GPs and community pharmacists) or to refer patients to secondary care. The target recruitment number for individuals is 576. The primary outcome is treatment completion (defined as taking at least 90% of antibiotic doses). The secondary outcomes assess adherence, acceptance of treatment, the incidence of adverse effects including drug-induced liver injury, the rates of active TB, patient satisfaction and cost-effectiveness of LTBI treatment. This protocol adheres to the SPIRIT Checklist. DISCUSSION: The CATAPuLT trial seeks to provide implementation research evidence for a patient-centred intervention to improve treatment completion for LTBI amongst recent migrants to the UK. TRIAL REGISTRATION: NCT03069807, March 2017, registered retrospectively

    Dogs with separation-related problems show a “less pessimistic” cognitive bias during treatment with fluoxetine (Reconcile™) and a behaviour modification plan

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    Background Canine separation-related problems (SRP) (also described as “separation anxiety” or “separation distress”) are among the most common behavioural complaints of dog owners. Treatment with psychoactive medication in parallel with a behaviour modification plan is well documented in the literature, but it is unknown if this is associated with an improvement in underlying affective state (emotion and mood) or simply an inhibition of the behaviour. Cognitive judgement bias tasks have been proposed as a method for assessing underlying affective state and so we used this approach to identify if any change in clinical signs during treatment was associated with a consistent change in cognitive bias (affective state). Five dogs showing signs of SRP (vocalising – e.g. barking, howling-, destruction of property, and toileting – urination or defecation- when alone) were treated with fluoxetine chewable tablets (Reconcile™) and set on a standard behaviour modification plan for two months. Questionnaires and interviews of the owners were used to monitor the clinical progress of the dogs. Subjects were also evaluated using a spatial cognitive bias test to infer changes in underlying affect prior to, and during, treatment. Concurrently, seven other dogs without signs of SRP were tested in the same way to act as controls. Furthermore, possible correlations between cognitive bias and clinical measures were also assessed for dogs with SRP. Results Prior to treatment, the dogs with SRP responded to ambiguous positions in the cognitive bias test negatively (i.e. with slower running speeds) compared to control dogs (p &lt; 0.05). On weeks 2 and 6 of treatment, SRP dogs displayed similar responses in the cognitive bias test to control dogs, consistent with the possible normalization of affect during treatment, with this effect more pronounced at week 6 (p &gt; 0.05). Questionnaire based clinical measures were significantly correlated among themselves and with performance in the cognitive bias test. Conclusion These results demonstrate for the first time that the clinical treatment of a negative affective state and associated behaviours in a non-human species can produce a shift in cognitive bias. These findings demonstrate how the outcome of an intervention on a clinical problem can be evaluated to determine not only that the subject’s behaviour has improved, but also its psychological state (welfare
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