Testing lepton flavour universality in semileptonic Λb→Λc∗\Lambda_b \to \Lambda_c^* decays

Lepton Flavour Universality tests with semileptonic $\Lambda_b\to\Lambda_c^*$ decays are important to corroborate the present anomalies in the similar ratios $R_{D^{(*)}}$, and can provide complementary constraints on possible origins of these anomalies beyond the Standard Model. In this paper we provide - for the first time - all the necessary theoretical ingredients to perform and interpret measurements of $R_{\Lambda_c^*}$ at the LHCb experiment. For this, we revisit the heavy-quark expansion of the relevant hadronic matrix elements, and provide their expressions to order $\alpha_s$ and $1/m$ accuracy. Moreover, we study the sensitivity to the form factor parameters given the projected size and purity of upcoming and future LHCb datasets of $\Lambda_b\to \Lambda_c^*\mu\bar{\nu}$ decays. We demonstrate explicitly the need to perform a simultaneous fit to both $\Lambda_c^*$ final states. Finally, we provide projections for the uncertainty of $R_{\Lambda_c^*}$ based on the form factor analysis from semimuonic decays and theoretical relations based on the heavy-quark expansion.Comment: 27 pages, 6 figures. v2: Fixed error in subleading IW function, added supplementary information; conclusions unchange

Parthenogenesis is self-destructive for scaled reptiles

Parthenogenesis is rare in nature. With 39 described true parthenogens, scaled reptiles (Squamata) are the only vertebrates that evolved this reproductive strategy. Parthenogenesis is ecologically advantageous in the short term, but the young age and rarity of parthenogenetic species indicate it is less advantageous in the long term. This suggests parthenogenesis is self-destructive: it arises often but is lost due to increased extinction rates, high rates of reversal or both. However, this role of parthenogenesis as a self-destructive trait remains unknown. We used a phylogeny of Squamata (5388 species), tree metrics, null simulations and macroevolutionary scenarios of trait diversification to address the factors that best explain the rarity of parthenogenetic species. We show that parthenogenesis can be considered as self-destructive, with high extinction rates mainly responsible for its rarity in nature. Since these parthenogenetic species occur, this trait should be ecologically relevant in the short term.publishe

Capitalists in the twenty-first century

Have passive rentiers replaced the working rich at the top of the U.S. income distribution? Using income tax data linking 11 million firms to their owners, this paper finds that private business owners who actively manage their firms are key for top income inequality. Private business income accounts for most of the rise of top incomes since 2000 and the majority of top earners receive private business income|most of which accrues to active owner-managers of mid-market firms in relatively skill-intensive and unconcentrated industries. Profit falls substantially after premature owner deaths. Top-owned firms are twice as profitable per worker as other firms despite similar risk, and rising profitability without rising scale explains most of their profit growth. Together, these facts indicate that the working rich remain central to rising top incomes in the twenty-first century

The clinical- and cost-effectiveness of functional electrical stimulation and ankle-foot orthoses for foot drop in Multiple Sclerosis: a multicentre randomized trial

Objective: To compare the clinical- and cost-effectiveness of ankle-foot orthoses (AFOs) and functional electrical stimulation (FES) over 12 months in people with Multiple Sclerosis with foot drop. Design: Multicentre, powered, non-blinded, randomized trial. Setting: Seven Multiple Sclerosis outpatient centres across Scotland. Subjects: Eighty-five treatment-naïve people with Multiple Sclerosis with persistent (>three months) foot drop. Interventions: Participants randomized to receive a custom-made, AFO (n = 43) or FES device (n = 42). Outcome measures: Assessed at 0, 3, 6 and 12 months; 5-minute self-selected walk test (primary), Timed 25 Foot Walk, oxygen cost of walking, Multiple Sclerosis Impact Scale-29, Multiple Sclerosis Walking Scale-12, Modified Fatigue Impact Scale, Euroqol five-dimension five-level questionnaire, Activities-specific Balance and Confidence Scale, Psychological Impact of Assistive Devices Score, and equipment and National Health Service staff time costs of interventions. Results: Groups were similar for age (AFO, 51.4 (11.2); FES, 50.4(10.4) years) and baseline walking speed (AFO, 0.62 (0.21); FES 0.73 (0.27) m/s). In all, 38% dropped out by 12 months (AFO, n = 21; FES, n = 11). Both groups walked faster at 12 months with device (P < 0.001; AFO, 0.73 (0.24); FES, 0.79 (0.24) m/s) but no difference between groups. Significantly higher Psychological Impact of Assistive Devices Scores were found for FES for Competence (P = 0.016; AFO, 0.85(1.05); FES, 1.53(1.05)), Adaptability (P = 0.001; AFO, 0.38(0.97); FES 1.53 (0.98)) and Self-Esteem (P = 0.006; AFO, 0.45 (0.67); FES 1 (0.68)). Effects were comparable for other measures. FES may offer value for money alternative to usual care. Conclusion: AFOs and FES have comparable effects on walking performance and patient-reported outcomes; however, high drop-outs introduces uncertainty

A two-stage approach for measuring vascular water exchange and arterial transit time by diffusion-weighted perfusion MRI

Changes in the exchange rate of water across the blood-brain barrier, denoted kw, may indicate blood-brain barrier dysfunction before the leakage of large-molecule contrast agents is observable. A previously proposed approach for measuring kw is to use diffusion-weighted arterial spin labeling to measure the vascular and tissue fractions of labeled water, because the vascular-to-tissue ratio is related to kw. However, the accuracy of diffusion-weighted arterial spin labeling is affected by arterial blood contributions and the arterial transit time (τa). To address these issues, a two-stage method is proposed that uses combinations of diffusion-weighted gradient strengths and post-labeling delays to measure both τa and kw. The feasibility of this method was assessed by acquiring diffusion-weighted arterial spin labeling data from seven healthy volunteers. Repeat measurements and Monte Carlo simulations were conducted to determine the precision and accuracy of the kw estimates. Average grey and white matter kw values were 110 ± 18 and 126 ± 18 min-1, respectively, which compare favorably to blood-brain barrier permeability measurements obtained with positron emission tomography. The intrasubject coefficient of variation was 26% ± 23% in grey matter and 21% ± 17% in white matter, indicating that reproducible kw measurements can be obtained. Copyright © 2011 Wiley Periodicals, Inc

The effectiveness and cost effectiveness of dark chocolate consumption as prevention therapy in people at high risk of cardiovascular disease: best case scenario analysis using a Markov model

Objective To model the long term effectiveness and cost effectiveness of daily dark chocolate consumption in a population with metabolic syndrome at high risk of cardiovascular disease

Book Reviews

The following publications have been reviewed by the authors;The Good Technology Guide 1994 - reviewed by Danny OwenObjects and Images: Studies in Design and Advertising - reviewed by Prof. P. RobertsClassroom Pedagogy and Primary Practice - reviewed by Alan CrossBasic Electronics For Tomorrow's World - reviewed by Allan TruemanBeyond The Core Curriculum - reviewed by  CD. SnellFood For Thought - reviewed by Rhona Humphrie

The Benefits of Using XML Technologies in Astronomical Data Retrieval and Interpretation

This paper describes a solution found during recent research that could provide improvements in the efficiency, reliability and cost of retrieving stored astronomical data. This solution uses XML Technologies in showing that when querying a variety of astronomical data sources a standardised data structure can be output into an XML query results Document. This paper shows the astronomical XMLSchema that has been partially developed in conjunction with simple custom supporting system software. It also discusses briefly possible future implications

Numerical calculation of strong-field laser-atom interaction: An approach with perfect reflection-free radiation boundary conditions

The time-dependent, single-particle Schrodinger equation with a finite-range potential is solved numerically on a three-dimensional spherical domain. In order to correctly account for outgoing waves, perfect reflection-free radiation boundary conditions are used on the surface of a sphere. These are computationally most effective if the particle wavefunction is expanded in the set of spherical harmonics and computations are performed in the Kramers-Henneberger accelerated frame. The method allows one to solve the full ionization dynamics in intense laser fields within a small region of atomic dimensions

A comparison of the initial orthotic effects of functional electrical stimulation and ankle-foot orthoses on the speed and oxygen cost of gait in multiple sclerosis

Foot drop affects walking in people with multiple sclerosis (pwMS). This study compares the initial orthotic effects of two treatments for foot drop: ankle-foot orthoses (AFO) and functional electrical stimulation (FES), on the speed and oxygen cost of walking in MS. Method and materials: Seventy-eight pwMS were randomised to receive AFO or FES (ODFS PACE (OML, Salisbury, UK)). Participants completed the 25-ft walk test (25ftWT) and 5-min self-selected walk test (5minSSWT), from which oxygen cost was determined, with and without their device. Between-, within- and sub-group analyses (based on baseline walking speed of <0.8 m/s (slow) or ≥0.8 m/s (fast)) were undertaken. Results: No significant differences between baseline measures were observed. The AFO group walked significantly slower than the FES group (5minSSWT, p = 0.037, 0.11 m/s). The AFO group walked significantly slower with than without AFO (25ftWT, p = 0.037), particularly in the fast-walking group ( p = 0.011). The slow-walking FES group walked significantly faster with FES than without (25ftWT; p = 0.029, 5minSSWT; p = 0.037). There were no differences in the fast-walking FES group or in the oxygen cost for either device. Conclusion: AFO reduced walking speed, particularly in fast walkers. FES increased walking speed in slow, but not fast walkers