Minimal massive 3D gravity unitarity redux

A geometrical analysis of the bulk and anti-de Sitter boundary unitarity conditions of 3D “Minimal Massive Gravity” (MMG) (which evades the “bulk/boundary clash” of Topologically Massive Gravity) is used to extend and simplify previous results, showing that unitarity selects, up to equivalence, a connected region in parameter space. We also initiate the study of flat-space holography for MMG.A.S.A. and P.K.T. acknowledge support from the UK Science and Technology Facilities Council (grant ST/L000385/1). A.S.A. also acknowledges support from Clare Hall College, Cambridge, and from the Cambridge Trust. We are grateful to Eduardo Casali, Elias Kiritsis and Alasdair Routh for helpful discussions, and to Eric Bergshoeff and Wout Merbis for helpful correspondence.This is the final version of the article. It was first published by IOP at https://camacuk.zendesk.com/agent/tickets/626

Twistor description of spinning particles in AdS

The two-twistor formulation of particle mechanics in D-dimensional anti-de Sitter space for D=4,5,7, which linearises invariance under the AdS isometry group Sp(4;K) for K=R,C,H,, is generalized to the massless N-extended ``spinning particle''. The twistor variables are gauge invariant with respect to the initial N local worldline supersymmetries; this simplifies aspects of the quantum theory such as implications of global gauge anomalies. We also give details of the two-supertwistor form of the superparticle, in particular the massive superparticle on AdS5

Worldline CPT and massless supermultiplets

The action for a massless particle in 4D Minkowski space–time has a worldline-time reversing symmetry corresponding to CPT invariance of the quantum theory. The analogous symmetry of the $\mathscr{N}$-extended superparticle is shown to be anomalous when $\mathscr{N}$ is odd; in the supertwistor formalism this is because a CPT-violating worldline-Chern–Simons term is needed to preserve the chiral $\textbf{U(1)}$ gauge invariance. This accords with the fact that no massless $\mathscr{N}$=1 super-Poincaré irrep is CPT-self-conjugate. There is a CPT self-conjugate supermultiplet when $\mathscr{N}$ is even, but it has $\textbf{2}$$^{\mathscr{N}+1}$ states when $\frac{1}{2}$$\mathscr{N}$ is odd (e.g. the $\mathscr{N}$=2 hypermultiplet) in contrast to just $\textbf{2}$$^{\mathscr{N}}$ when $\frac{1}{2}$$\mathscr{N}$ is even (e.g. the $\mathscr{N}$=4 Maxwell supermultiplet). This is shown to follow from a Kramers degeneracy of the superparticle state space when $\frac{1}{2}$$\mathscr{N}$ is odd.A.S. Arvanitakis and P. K. Townsend acknowledge support from the UK Science and Technology Facilities Council (grant ST/L000385/1).A.S. Arvanitakis also acknowledges support from Clare Hall College, Cambridge, and from the Cambridge Trust

Pauli-Lubanski, supertwistors, and the superspinning particle

We present a novel construction of the super-Pauli-Lubanski pseudo-vector for 4D supersymmetry and show how it arises naturally from the spin-shell constraints in the supertwistor formulation of superparticle dynamics. We illustrate this result in the context of a simple classical action for a “superspinning particle” of superspin 1/2. We then use an Sl(2;K)-spinor formalism for K=ℝ,ℂ,ℍ to unify our 4D results with previous results for 3D and 6D

Anti-de Sitter Particles and Manifest (Super)Isometries.

Starting from the classical action for a spin-zero particle in a D-dimensional anti-de Sitter (AdS) spacetime, we recover the Breitenlohner-Freedman bound by quantization. For D=4, 5, 7 and using an Sl(2;K) spinor notation for K=R,C,H, we find a bitwistor form of the action for which the AdS isometry group is linearly realized, although only for zero mass when D=4, 7 in agreement with previous constructions. For zero mass and D=4 the conformal isometry group is linearly realized. We extend these results to the superparticle in the maximally supersymmetric "AdS×S" string or M-theory vacua, showing that quantization yields a 128+128 component supermultiplet. We also extend them to the null string.We acknowledge support from the UK Science and Technology Facilities Council (Grants No. ST/L000385/1 and No. ST/M50340X/1). A. S. A. also acknowledges support from the INFN, from Clare Hall College Cambridge, from DAMTP, from the Cambridge Philosophical Society, and from the Cambridge Trust

The benefits and risks of bacille Calmette-Guérin vaccination among infants at high risk for both tuberculosis and severe combined immunodeficiency: assessment by Markov model

BACKGROUND: Bacille Calmette-Guérin (BCG) vaccine is given to Canadian Aboriginal neonates in selected communities. Severe reactions and deaths associated with BCG have been reported among infants born with immunodeficiency syndromes. The main objective of this study was to estimate threshold values for severe combined immunodeficiency (SCID) incidence, above which BCG is associated with greater risk than benefit. METHODS: A Markov model was developed to simulate the natural histories of tuberculosis (TB) and SCID in children from birth to 14 years. The annual risk of tuberculous infection (ARI) and SCID incidence were varied in analyses. The model compared a scenario of no vaccination to intervention with BCG. Appropriate variability and uncertainty analyses were conducted. Outcomes included TB incidence and quality-adjusted life years (QALYs). RESULTS: In sensitivity analyses, QALYs were lower among vaccinated infants if the ARI was 0.1% and the rate of SCID was higher than 4.2 per 100,000. Assuming an ARI of 1%, this threshold increased to 41 per 100,000. In uncertainty analyses (Monte Carlo simulations) which assumed an ARI of 0.1%, QALYs were not significantly increased by BCG unless SCID incidence is 0. With this ARI, QALYs were significantly decreased among vaccinated children if SCID incidence exceeds 23 per 100,000. BCG is associated with a significant increase in QALYs if the ARI is 1%, and SCID incidence is below 5 per 100,000. CONCLUSION: The possibility that Canadian Aboriginal children are at increased risk for SCID has serious implications for continued BCG use in this population. In this context, enhanced TB Control – including early detection and treatment of infection – may be a safer, more effective alternative

The effect of regular walks on various health aspects in older people with dementia: protocol of a randomized-controlled trial

<p>Abstract</p> <p>Background</p> <p>Physical activity has proven to be beneficial for physical functioning, cognition, depression, anxiety, rest-activity rhythm, quality of life (QoL), activities of daily living (ADL) and pain in older people. The aim of this study is to investigate the effect of walking regularly on physical functioning, the progressive cognitive decline, level of depression, anxiety, rest-activity rhythm, QoL, ADL and pain in older people with dementia.</p> <p>Methods/design</p> <p>This study is a longitudinal randomized controlled, single blind study. Ambulatory older people with dementia, who are regular visitors of daily care or living in a home for the elderly or nursing home in the Netherlands, will be randomly allocated to the experimental or control condition. Participants of the experimental group make supervised walks of 30 minutes a day, 5 days a week, as part of their daily nursing care. Participants of the control group will come together three times a week for tea or other sedentary activities to control for possible positive effects of social interaction. All dependent variables will be assessed at baseline and after 6 weeks, and 3, 6, 9, 12 and 18 months of intervention.</p> <p>The dependent variables include neuropsychological tests to assess cognition, physical tests to determine physical functioning, questionnaires to assess ADL, QoL, level of depression and anxiety, actigraphy to assess rest-activity rhythm and pain scales to determine pain levels. Potential moderating variables at baseline are: socio-demographic characteristics, body mass index, subtype of dementia, apolipoprotein E (ApoE) genotype, medication use and comorbidities.</p> <p>Discussion</p> <p>This study evaluates the effect of regular walking as a treatment for older people with dementia. The strength of this study is that 1) it has a longitudinal design with multiple repeated measurements, 2) we assess many different health aspects, 3) the intervention is not performed by research staff, but by nursing staff which enables it to become a routine in usual care. Possible limitations of the study are that 1) only active minded institutions are willing to participate creating a selection bias, 2) the drop-out rate will be high in this population, 3) not all participants will be able to perform/understand all tests.</p> <p>Trial registration</p> <p><a href="http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=1482">NTR1482</a></p