LVMB manifolds and simplicial spheres

LVM and LVMB manifolds are a large family of examples of non kahler manifolds. For instance, Hopf manifolds and Calabi-Eckmann manifolds can be seen as LVMB manifolds. The LVM manifolds have a very natural action of the real torus and the quotient of this action is a simple polytope. This quotient allows us to relate closely LVM manifolds to the moment-angle manifolds studied (for example) by Buchstaber and Panov. The aim of this paper is to generalize the polytopes associated to LVM manifolds to the LVMB case and study its properties. In particular, we show that it belongs to a very large class of simplicial spheres. Moreover, we show that for every sphere belonging to this class, we can construct a LMVB manifold whose associated sphere is the given sphere. We use this latter result to show that many moment-angle complexes can be endowed with a complex structure (up to product with circles)

Behavioral characterization of acetaldehyde in C57BL/6J mice: Anxiolytic, amnesic and hedonic effects

It has been postulated that a number of central effects of ethanol are mediated through the action of its first metabolite, acetaldehyde. In particular, acetaldehyde might be involved in the anxiolytic and hedonic effects of ethanol and is therefore believed to play an important role in alcohol abuse. In agreement with this assumption, previous studies indicated that acetaldehyde is mainly reinforcing in rats, which have been shown to readily self-administer acetaldehyde both peripherally and centrally. However, the hedonic effects of acetaldehyde have never been tested in mice, and the possible amnesic and anxiolytic effects of acetaldehyde remain to be elucidated. Therefore, the present studies were aimed at characterizing the anxiolytic, hedonic and amnesic effects of acetaldehyde after its acute peripheral administration to C57BL/6J mice. The effects of intraperitoneal acetaldehyde (0-300 mg/kg) injections were assessed in several classical behavioral tests. The anxiolytic effects were tested with the elevated plus maze, the hedonic effects with the place conditioning procedure and the amnesic effects with the passive avoidance apparatus. Our results show that acetaldehyde dose-dependently altered memory consolidation as evidenced by a reduced performance in the passive avoidance test when acetaldehyde was injected immediately after training at doses between 100 and 300 mg/kg. The elevated plus-maze showed that acetaldehyde, in contrast to ethanol, does not possess anxiolytic properties. Finally, the results of the place conditioning experiment confirmed that acetaldehyde displays significant hedonic properties. The present results add further support to the role of acetaldehyde in ethanol amnesic and hedonic effects but interestingly suggest that acetaldehyde is not involved in ethanol anxiolytic effects

The death of cost-minimization analysis?

Four different types of evaluation methods, cost-benefit analysis (CBA), cost-utility analysis (CUA), cost-effectiveness analysis (CEA) and cost-minimization analysis (CMA), are usually distinguished. In this note, we pronounce the (near) death of CMA by showing the rare circumstances under which CMA is an appropriate method of analysis. We argue that it is inappropriate for separate and sequential hypothesis tests on differences in effects and costs to determine whether incremental cost-effectiveness (or cost-utility) should be estimated. We further argue that the analytic focus should be on the estimation of the joint density of cost and effect differences, the quantification of uncertainty surrounding the incremental cost-effectiveness ratio and the presentation of such data as cost-effectiveness acceptability curves. Two examples from recently published CEA are employed to illustrate the issues. The first shows a situation where analysts might be tempted (inappropriately) to employ CMA rather than CEA. The second illustrates one of the rare circumstances in which CMA may be justified as a legitimate form of analysis

A Noncrossing Basis for Noncommutative Invariants of SL(2,C)

Noncommutative invariant theory is a generalization of the classical invariant theory of the action of SL(2,\IC) on binary forms. The dimensions of the spaces of invariant noncommutative polynomials coincide with the numbers of certain noncrossing partitions. We give an elementary combinatorial explanation of this fact by constructing a noncrossing basis of the homogeneous components. Using the theory free stochastic measures this provides a combinatorial proof of the Molien-Weyl formula in this setting.Comment: AMS LaTeX, 13 pages, using Asymptote picture

On the probability of cost-effectiveness using data from randomized clinical trials

BACKGROUND: Acceptability curves have been proposed for quantifying the probability that a treatment under investigation in a clinical trial is cost-effective. Various definitions and estimation methods have been proposed. Loosely speaking, all the definitions, Bayesian or otherwise, relate to the probability that the treatment under consideration is cost-effective as a function of the value placed on a unit of effectiveness. These definitions are, in fact, expressions of the certainty with which the current evidence would lead us to believe that the treatment under consideration is cost-effective, and are dependent on the amount of evidence (i.e. sample size). METHODS: An alternative for quantifying the probability that the treatment under consideration is cost-effective, which is independent of sample size, is proposed. RESULTS: Non-parametric methods are given for point and interval estimation. In addition, these methods provide a non-parametric estimator and confidence interval for the incremental cost-effectiveness ratio. An example is provided. CONCLUSIONS: The proposed parameter for quantifying the probability that a new therapy is cost-effective is superior to the acceptability curve because it is not sample size dependent and because it can be interpreted as the proportion of patients who would benefit if given the new therapy. Non-parametric methods are used to estimate the parameter and its variance, providing the appropriate confidence intervals and test of hypothesis

Effectiveness and cost-effectiveness of a brief school-based group programme for parents of children at risk of ADHD: a cluster randomised controlled trial

Background NICE guidelines recommend a stepped care approach for the identification and management of children with, or at risk of, Attention-Deficit / Hyperactivity Disorder (ADHD). We investigated the effectiveness, cost-effectiveness and acceptability of a group parenting intervention programme (+/- a teacher session) for children at risk of ADHD. Methods In a three-arm cluster RCT, 12 primary schools were randomly assigned to control, parent-only, and combined (parent + teacher) intervention arms. Eligible children had high levels of parent-rated hyperactivity/inattention (n=199). At six month follow-up, the primary outcome measure was the parent-completed Conners’ Rating Scale – Revised (ADHD Index). Secondary outcomes included the Conners’ sub-scales (hyperactivity, cognitive problems/inattention, oppositional behaviour), the teacher-completed Conners’ Rating Scale – Revised, child health-related quality of life, parental burden and parental mental health. The cost-effectiveness analyses reflected a health and personal social services perspective. Trial Registration:ISRCTN87634685. Results Follow-up data were obtained from 76 parents and 169 teachers. There was no effect of the parentonly (mean difference = -1.1, 95% CI -5.1,2.9; p=0.57) or combined interventions (mean difference = -2.1, 95% CI -6.4,2.1; p=0.31) on the ADHD Index. The combined intervention was associated with reduced parent-reported hyperactivity symptoms (mean difference = -5.3; 95% CI -10.5,-0.01; p=0.05) and the parent-only intervention with improved parental mental health (mean difference = - 1.9; 95% CI -3.2,-0.5; p=0.009). The incremental costs of the parent-only and the combined interventions were £73 and £123 respectively. Above a willingness to pay of £31 per 1-point improvement in the ADHD index, the parent-only programme had the highest probability of cost effectiveness. Participants found the interventions acceptable. Conclusions For children at risk of ADHD, this school-based parenting programme was not associated with improvement in core ADHD symptoms. Secondary analyses suggested a possible reduction in parent-reported hyperactivity and parental mental health problems. Future research should compare targeted interventions against watchful waiting and specialist referral

Gamma Hydroxybutyric Acid (GHB) for the Treatment of Alcohol Dependence: A Review

Gamma-hydroxybutyric acid (GHB) is a short-chain fatty acid structurally similar to the inhibitory neurotransmitter γ-aminobutyric acid. Clinical trials have demonstrated that 50–100 mg/kg of GHB fractioned into three or six daily doses is able to suppress alcohol withdrawal symptoms and facilitates the maintenance of abstinence from alcohol. These studies have also shown that GHB craving episodes are a very limited phenomenon (about 10–15%). Thus, physicians with access should consider the clinical efficacy of GHB as a valid pharmacological tool for the treatment of alcohol addiction