4,086 research outputs found

    An upper limit on CP violation in the Bs0Bˉs0B^0_s-\bar{B}^0_s system

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    In a previous publication we noted that the time dependence of an incoherent B0Bˉ0B^0-\bar{B}^0 mixture undergoes a qualitative change when the magnitude of CP violation δ\delta exceeds a critical value. Requiring, on physical grounds, that the system evolve from an initial incoherent state to a final pure state in a monotonic way, yields a new upper limit for δ\delta. The recent measurement of the wrong charge semileptonic asymmetry of Bs0B_s^0 mesons presented by the D0 collaboration is outside this bound by one standard deviation. If this result is confirmed it implies the existence of a new quantum mechanical oscillation phenomenon.Comment: 7 pages, 2 figures, version submitted for publication (Physical Review

    Model adaptation and adaptive training for the recognition of dysarthric speech

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    Dysarthria is a neurological speech disorder, which exhibits multi-fold disturbances in the speech production system of an individual and can have a detrimental effect on the speech output. In addition to the data sparseness problems, dysarthric speech is characterised by inconsistencies in the acoustic space making it extremely challenging to model. This paper investigates a variety of baseline speaker independent (SI) systems and its suitability for adaptation. The study also explores the usefulness of speaker adaptive training (SAT) for implicitly annihilating inter-speaker variations in a dysarthric corpus. The paper implements a hybrid MLLR-MAP based approach to adapt the SI and SAT systems. ALL the results reported uses UASPEECH dysarthric data. Our best adapted systems gave a significant absolute gain of 11.05% (20.42% relative) over the last published best result in the literature. A statistical analysis performed across various systems and its specific implementation in modelling different dysarthric severity sub-groups, showed that, SAT-adapted systems were more applicable to handle disfluencies of more severe speech and SI systems prepared from typical speech were more apt for modelling speech with low level of severity

    Malaria in Pregnancy

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    Malaria infection during pregnancy is an important public health problem with substantial risks to both the mother and foetus. Pregnant women are the most vulnerable group of malaria‐associated morbidity and mortality. A pregnant woman has an increased risk (up to four times) of getting malaria and twice the chances of dying from malaria, compared to a non‐pregnant adult, becuase the immune system is partially suppressed during pregnancy. Malaria in pregnancy not only affects the mother but also has a dangerous sequel for the developing foetus, resulting in premature delivery or intrauterine growth retardation. Diagnosis of malaria in pregnancy remains a challenge due to the low parasite density and placental sequestration of Plasmodium falciparum. Thus, there is an urgent need for new diagnostic methods to detect malarial parasites in the pregnant women. Though antimalarial drugs are available, which can be safely given in the pregnancy, increasing drug resistance of malarial parasite may pose a big problem in the future. In this chapter, we review the burden of pregnancy‐associated malaria (PAM), its pathogenesis, diagnostic issues during pregnancy and recent guidelines for chemoprophylaxsis and treatment

    Investigation of nose bluntness and angle of attack effects on slender bodies in viscous hypersonic flows

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    Hypersonic flows over cones and straight biconic configurations are calculated for a wide range of free stream conditions in which the gas behind the shock is treated as perfect. Effect of angle of attack and nose bluntness on these slender cones in air is studied extensively. The numerical procedures are based on the solution of complete Navier-Stokes equations at the nose section and parabolized Navier-Stokes equations further downstream. The flow field variables and surface quantities show significant differences when the angle of attack and nose bluntness are varied. The complete flow field is thoroughly analyzed with respect to velocity, temperature, pressure, and entropy profiles. The post shock flow field is studied in detail from the contour plots of Mach number, density, pressure, and temperature. The effect of nose bluntness for slender cones persists as far as 200 nose radii downstream

    CMB Lensing Power Spectrum Biases from Galaxies and Clusters using High-angular Resolution Temperature Maps

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    The lensing power spectrum from cosmic microwave background (CMB) temperature maps will be measured with unprecedented precision with upcoming experiments, including upgrades to ACT and SPT. Achieving significant improvements in cosmological parameter constraints, such as percent level errors on sigma_8 and an uncertainty on the total neutrino mass of approximately 50 meV, requires percent level measurements of the CMB lensing power. This necessitates tight control of systematic biases. We study several types of biases to the temperature-based lensing reconstruction signal from foreground sources such as radio and infrared galaxies and the thermal Sunyaev-Zel'dovich effect from galaxy clusters. These foregrounds bias the CMB lensing signal due to their non-Gaussian nature. Using simulations as well as some analytical models we find that these sources can substantially impact the measured signal if left untreated. However, these biases can be brought to the percent level if one masks galaxies with fluxes at 150 GHz above 1 mJy and galaxy clusters with masses above M_vir = 10^14 M_sun. To achieve such percent level bias, we find that only modes up to a maximum multipole of l_max ~ 2500 should be included in the lensing reconstruction. We also discuss ways to minimize additional bias induced by such aggressive foreground masking by, for example, exploring a two-step masking and in-painting algorithm.Comment: 14 pages, 14 figures, to be submitted to Ap

    Longitudinal Polarization in KLμ+μK_L \to \mu^+ \mu^- in MSSM with large tanβtan\beta

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    A complete experiment on decay KLl+lK_L \to l^+ l^- will not only consist of measurement of the decay rates but also lepton polarization etc. These additional observations will yield tests of CP invariance in these decays. In KLK_L and KSK_S decays, the e mode is slower than the μ\mu mode by roughly (me/mμ)2(m_e/m_\mu)^2 \cite{sehgal1}. As well discussed in literature \cite{herczeg} the Standard Model contribution to the lepton polarization is of order 2×1032 \times \sim 10^{-3}. We show that in MSSM with large \tanbeta and light higgs masses (2MW\sim 2 M_W), the longitudinal lepton polarization in KLμ+μK_L \to \mu^+ \mu^- can be enhanced to a higher value, of about 10210^{-2}.Comment: version appeared in Physics Letters B, minor correction

    Systematics of K-Isomerism

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    Finite Matrix Groups over Nilpotent Group Rings

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    AbstractWe study groups of matricesSGLn(ZΓ) of augmentation one over the integral group ring ZΓ of a nilpotent group Γ. We relate the torsion ofSGLn(ZΓ) to the torsion of Γ. We prove that all abelianp-subgroups ofSGLn(ZΓ) can be stably diagonalized. Also, all finite subgroups ofSGLn(ZΓ) can be embedded into the diagonal Γn<SGLn(ZΓ). We apply matrix results to show that if Γ is nilpotent-by-(Π′-finite) then all finite Π-groups of normalized units in ZΓ can be embedded into Γ
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