1,000 research outputs found

    Analysis of enhanced tan(beta) corrections in MFV GUT scenarios

    Full text link
    We analyse a minimal supersymmetric standard model (MSSM) taking a minimal flavour violation (MFV) structure at the GUT scale. We evaluate the parameters at the electroweak scale taking into account the full flavour structure in the evolution of the renormalization group equations. We concentrate mainly on the decay Bs -> mu mu and its correlations with other observables like b -> s gamma, b -> s l l, Delta M_Bs and the anomalous magnetic moment of the muon. We restrict our analysis to the regions in parameter space consistent with the dark matter constraints. We find that the BR(Bs -> mu mu) can exceed the current experimental limit in the regions of parameter space which are allowed by all other constraints thus providing an additional bound on supersymmetric parameters. This holds even in the constrained MSSM. Assuming an hypothetical measurement of BR(Bs -> mu mu) ~ 10^-7 we analyse the predicted MSSM spectrum and flavour violating decay modes of supersymmetric particles which are found to be small.Comment: 47 pages, 16 figures (best viewed printed or in pdf format), updated lattice inputs used, version submitted to PR

    Improved Model-Independent Analysis of Semileptonic and Radiative Rare B Decays

    Get PDF
    We update the branching ratios for the inclusive decays B→Xsℓ+ℓ−B\to X_s \ell^+ \ell^- and the exclusive decays B→(K,K∗)ℓ+ℓ−B\to (K,K^*) \ell^+ \ell^-, with \ell=e, \m, in the standard model by including the explicit O(\a_s) and ΛQCD/mb\Lambda_{\hbox{\tiny QCD}} / m_b corrections. This framework is used in conjunction with the current measurements of the branching ratios for B\to X_s \g and B→Kℓ+ℓ−B\to K \ell^+ \ell^- decays and upper limits on the branching ratios for the decays B→(K∗,Xs)ℓ+ℓ−B\to (K^*,X_s) \ell^+ \ell^- to work out bounds on the Wilson coefficients C7C_7, C8C_8, C9C_9 and C10C_{10} appearing in the effective Hamiltonian formalism. The resulting bounds are found to be consistent with the predictions of the standard model and some variants of supersymmetric theories. We illustrate the constraints on supersymmetric parameters that the current data on rare B decays implies in the context of minimal flavor violating model and in more general scenarios admitting additional flavor changing mechanisms. Precise measurements of the dilepton invariant mass distributions in the decays B→(Xs,K∗,K)ℓ+ℓ−B \to (X_s,K^*,K) \ell^+ \ell^-, in particular in the lower dilepton mass region, and the forward-backward asymmetry in the decays B→(Xs,K∗)ℓ+ℓ−B \to (X_s,K^*) \ell^+ \ell^-, will greatly help in discriminating among the SM and various supersymmetric theories

    Neutrino masses and flavor symmetries

    Full text link
    The problem of neutrino masses and mixing angles is analysed in a class of supersymmetric grand unified models, with SO(10) gauge symmetry and global U(2) flavour symmetry. Adopting the seesaw mechanism for the generation of the neutrino masses, one obtains a mass matrix for the left-handed neutrinos which is directly related to the parameters of the charged sector, while the unknown parameters of the right-handed Majorana mass matrix are inglobed in a single factor.Comment: 17 pages, 1 eps figure, uses graphicx.sty, LaTeX 2e, to be published on "Il Nuovo Cimento

    Single photonics at telecom wavelengths using nanowire superconducting detectors

    Get PDF
    Single photonic applications - such as quantum key distribution - rely on the transmission of single photons, and require the ultimate sensitivity that an optical detector can achieve. Single-photon detectors must convert the energy of an optical pulse containing a single photon into a measurable electrical signal. We report on fiber-coupled superconducting single-photon detectors (SSPDs) with specifications that exceed those of avalanche photodiodes (APDs), operating at telecommunication wavelength, in sensitivity, temporal resolution and repetition frequency. The improved performance is demonstrated by measuring the intensity correlation function g(2)(t) of single-photon states at 1300nm produced by single semiconductor quantum dots (QDs).Comment: 7 pages, 5 figures - submitted 12 OCT 200

    Patient Active Approaches in Osteopathic Practice: A Scoping Review

    Get PDF
    Background: In the field of manual therapies there is a growing interest in moving from passive hands-on approaches to patient active approaches. In the osteopathic field there are both active and passive methods described as integrated in the process of care. However, this prospective linkage has not been formally explored and is not well shared in the community of practice. The present review aims to appraise the relevant literature on the functioning and principles of Patient active osteopathic approaches (PAOAs) and explore a prospective model for selecting the different types of PAOA, highlighting their integration into patient management strategies. Methods: A scoping review was conducted to analyze the relevant literature on the functioning and the different principles of PAOA and to obtain a comprehensive perspective on the phenomenon. Results: The eligible articles provide insights into the mechanisms of functioning and principles of application of active approaches to be integrated with hands-on approaches. These results provide new insights into the relevance of PAOA to clinical practice. Conclusions: The proposal, emerging from the review, may promote discussions in the community of practice and provide a road map for research towards achieving an evidence-based structure for PAOA

    Complete gluon bremsstrahlung corrections to the process b -> s l+ l-

    Full text link
    In a recent paper, we presented the calculation of the order (alpha_s) virtual corrections to b->s l+ l- and of those bremsstrahlung terms which are needed to cancel the infrared divergences. In the present paper we work out the remaining order(alpha_s) bremsstrahlung corrections to b->s l+ l- which do not suffer from infrared and collinear singularities. These new contributions turn out to be small numerically. In addition, we also investigate the impact of the definition of the charm quark mass on the numerical results.Comment: 20 pages including 11 postscript figure

    GM1 Ganglioside Is A Key Factor in Maintaining the Mammalian Neuronal Functions Avoiding Neurodegeneration

    Get PDF
    Many species of ganglioside GM1, differing for the sialic acid and ceramide content, have been characterized and their physico\u2010chemical properties have been studied in detail since 1963. Scientists were immediately attracted to the GM1 molecule and have carried on an ever\u2010increasing number of studies to understand its binding properties and its neurotrophic and neuroprotective role. GM1 displays a well balanced amphiphilic behavior that allows to establish strong both hydrophobic and hydrophilic interactions. The peculiar structure of GM1 reduces the fluidity of the plasma membrane which implies a retention and enrichment of the ganglioside in specific membrane domains called lipid rafts. The dynamism of the GM1 oligosaccharide head allows it to assume different conformations and, in this way, to interact through hydrogen or ionic bonds with a wide range of membrane receptors as well as with extracellular ligands. After more than 60 years of studies, it is a milestone that GM1 is one of the main actors in determining the neuronal functions that allows humans to have an intellectual life. The progressive reduction of its biosynthesis along the lifespan is being considered as one of the causes underlying neuronal loss in aged people and severe neuronal decline in neurodegenerative diseases. In this review, we report on the main knowledge on ganglioside GM1, with an emphasis on the recent discoveries about its bioactive component

    Recent developments in radiative B decays

    Full text link
    We report on recent theoretical progress in radiative B decays. We focus on a calculation of logarithmically enhanced QED corrections to the branching ratio and forward-backward asymmetry in the inclusive rare decay anti-B --> X(s) l+ l-, and present the results of a detailed phenomenological analysis. We also report on the calculation of NNLO QCD corrections to the inclusive decay anti-B --> X(s) gamma. As far as exclusive modes are concerned we consider transversity amplitudes and the impact of right-handed currents in the exclusive anti-B --> K^* l+ l- decay. Finally, we state results for exclusive B --> V gamma decays, notably the time-dependent CP-asymmetry in the exclusive B --> K^* gamma decay and its potential to serve as a so-called ``null test'' of the Standard Model, and the extraction of CKM and unitarity triangle parameters from B --> (rho,omega) gamma and B --> K^* gamma decays.Comment: 5 pages, 2 figures. Accepted for publication in the proceedings of International Europhysics Conference on High Energy Physics (EPS-HEP2007), Manchester, England, 19-25 Jul 200

    Reconceptualizing Somatic Dysfunction in the Light of a Neuroaesthetic Enactive Paradigm

    Get PDF
    Background: Palpatory findings are considered a central element of osteopathic practice, especially when associated with a patient’s altered regulative functions than with named somatic dysfunctions. Although osteopathic theories for somatic dysfunction could be plausible, the clinical applicability of the concept is debated, especially because it is largely related to simple cause–effect models of osteopathic care. In contrast to a linear kind of diagnosis of a “tissue as a producer of symptoms”, this perspective article aims to provide a conceptual and operational framework in which the somatic dysfunction evaluation process is seen as a neuroaesthetic (en)active encounter between osteopath and patient. Subsections relevant to the subject: To summarize all concepts of the hypothesis, the enactive neuroaesthetics principles are proposed as a critical foundation for the osteopathic assessment and treatment of the person, specifically addressing a new paradigm for somatic dysfunction. Conclusions, and future directions: The present perspective article represents a proposition to blend technical rationality informed by neurocognitive and social sciences, and professional artistry clinical experience informed by traditional tenets, to overcome the controversy around somatic dysfunction, rather than dismissing the concept

    Characterization of the GM1 oligosaccharide transport across the blood-brain-barrier

    Get PDF
    Ganglioside GM1 has demonstrated to attenuate Parkinson Disease (PD) symptoms in clinical and preclinical trials. Nevertheless, the GM1 efficacy revealed in vitro is critically reduced in vivo, because of the amphiphilic behavior that limits the passage across the blood brain barrier (BBB). In vitro and in vivo experiments showed that GM1 exerts neurotrophic functions by interacting with plasma membrane (PM) proteins throughout its oligosaccharide portion (OligoGM1). Furthermore, OligoGM1 intravenously or subcutaneously injected into mice is absorbed and taken up by different organs and tissues, including brain. In order to take advantage of GM1 oligosaccharide properties and to overcome GM1 pharmacological limitation, this study has been aimed by the investigation of the OligoGM1 transportthrough the BBB, by using a human in vitro model for human brain-like endothelial cells (hBLEC). Ruled out the toxicity of OligoGM1 on hBLEC, the OligoGM1 transport across the hBBB has been analyzed, finding out a 20 fold higher rate than GM1 and a time and concentration dependence. In order to characterize the OligoGM1 passage, a direct evaluation of the OligoGM1 interaction with the ABC-transporters was carried on, leaving out this way for OligoGM1 transport. Moreover, inverse- and 4\ub0C-transport experiments were performed excluding the implication of the active transport for OligoGM1 passage across the hBLEC, leading to consider the passive-paracellular route. Furthermore, after the hBLEC transport, OligoGM1 maintained its stability and capacity to induce neuritogenesis in the mouse neuroblastoma cells line Neuro2a. This preliminary study has improved the knowledge about the GM1 pharmacological potential by proving that OligoGM1 can cross advantageously the BBB, offering a new promising therapeutic strategy
    • 

    corecore