Introduction: The difference that makes a difference

This article introduces TripleC’s Special Issue on The Difference That Makes a Difference, containing papers arising from a workshop of the same name that ran in Milton Keynes in September 2011. The background to the workshop is explained, workshop sessions are summarised, and the content of the papers introduced. Finally, some provisional outcomes from the workshop and the Special Issue are described

Analysis of Natural Gradient Descent for Multilayer Neural Networks

Natural gradient descent is a principled method for adapting the parameters of a statistical model on-line using an underlying Riemannian parameter space to redefine the direction of steepest descent. The algorithm is examined via methods of statistical physics which accurately characterize both transient and asymptotic behavior. A solution of the learning dynamics is obtained for the case of multilayer neural network training in the limit of large input dimension. We find that natural gradient learning leads to optimal asymptotic performance and outperforms gradient descent in the transient, significantly shortening or even removing plateaus in the transient generalization performance which typically hamper gradient descent training.Comment: 14 pages including figures. To appear in Physical Review

Collaborate to innovate

Innovation is something that many governments strive to support, in both the private and public sectors. By bridging the two sectors and creating novel partnerships, public sector expenditure can be reduced

Parrondo Strategies for Artificial Traders

On markets with receding prices, artificial noise traders may consider alternatives to buy-and-hold. By simulating variations of the Parrondo strategy, using real data from the Swedish stock market, we produce first indications of a buy-low-sell-random Parrondo variation outperforming buy-and-hold. Subject to our assumptions, buy-low-sell-random also outperforms the traditional value and trend investor strategies. We measure the success of the Parrondo variations not only through their performance compared to other kinds of strategies, but also relative to varying levels of perfect information, received through messages within a multi-agent system of artificial traders.Comment: 10 pages, 4 figure

Confidence Interval Estimation Tasks and the Economics of Overconfidence

Experiments in psychology, where subjects estimate confidence intervals to a series of factual questions, have shown that individuals report far too narrow intervals. This has been interpreted as evidence of overconfidence in the preciseness of knowledge, a potentially serious violation of the rationality assumption in economics. Following these results a growing literature in economics has incorporated overconfidence in models of, for instance, financial markets. In this paper we investigate the robustness of results from confidence interval estimation tasks with respect to a number of manipulations: frequency assessments, peer frequency assessments, iteration, and monetary incentives. Our results suggest that a large share of the overconfidence in interval estimation tasks is an artifact of the response format. Using frequencies and monetary incentives reduces the measured overconfidence in the confidence interval method by about 65%. The results are consistent with the notion that subjects have a deep aversion to setting broad confidence intervals, a reluctance that we attribute to a socially rational trade-off between informativeness and accuracy.overconfidence; uncertainty; monetary incentives; experiments

Fixed Budgets as a Cost Containment Measure for Pharmaceuticals

In the county of Västerbotten, Sweden, there are two health centres which (contrary to all other health centres in the region) have a strict responsibility over their pharmaceutical budget. The purpose of this paper is to examine if the prices and quantities of pharmaceuticals prescribed by physicians working at these health centres differ significantly from those prescribed by physicians at health centres with open-ended budgets. Estimation results using matching methods, which allows us to compare similar patients at the different health centres, show that the introduction of fixed pharmaceutical budgets did not affect physicians' prescription behaviour.pharmaceuticals; cost containment; propensity score matching

In vivo contact stresses at the radiocarpal joint using a finite element method of the complete wrist joint

A small number of cadaveric studies have been carried out looking at the force transmission through the radiocarpal joint. In this study subject specific finite element models were created of the whole wrist joint using measured biomechanical data to capture the forces acting on the wrist with the hand generating a maximum gripping force

One evidence base; three stories: do opioids relieve chronic breathlessness?

Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/. The efficacy of low-dose systemic opioids for chronic breathlessness was questioned by the recent Cochrane review by Barnes et al We examined the reasons for this conflicting finding and re-evaluated the efficacy of systemic opioids. Compared with previous meta-analyses, Barnes et al reported a smaller effect and lower precision, but did not account for matched data of crossover trials (11/12 included trials) and added a risk-of-bias criterion (sample size). When re-analysed to account for crossover data, opioids decreased breathlessness (standardised mean differences -0.32; -0.18 to -0.47; I2=44.8%) representing a clinically meaningful reduction of 0.8 points (0-10 numerical rating scale), consistent across meta-analyses

Breathlessness in the elderly during the last year of life sufficient to restrict activity

OBJECTIVES: Breathlessness is prevalent in older people. Symptom control at the end of life is important. This study investigated relationships between age, clinical characteristics and breathlessness sufficient to have people spend at least one half a day in that month in bed or cut down on their usual activities (restricting breathlessness) during the last year of life. DESIGN: Secondary data-analysis SETTING: General community PARTICIPANTS: 754 non-disabled persons, aged 70 and older. Monthly telephone interviews were conducted to determine the occurrence of restricting breathlessness. The primary outcome was the percentage of months with restricting breathlessness reported during the last year of life. RESULTS: Data regarding breathlessness were available for 548/589 (93.0%) decedents (mean age 86.7 years (range 71 to 106; males 38.8%). 311/548 (56.8%) reported restricting breathlessness at some time-point during the last year of life but no-one reported this every month. Frequency increased in the months closer to death irrespective of cause. Restricting breathlessness was associated with anxiety, (0.25 percentage point increase in months breathlessness per percentage point months reported anxiety, 95% CI 0.16 to 0.34, P<0.001), depression (0.14, 0.05 to 0.24, P=0.002) and mobility problems (0.07, 0.03 to 0.1, P=0.001). Percentage months of restricting breathlessness increased if chronic lung disease was noted at the most recent comprehensive assessment (6.62 percentage points, 95% CI 4.31 to 8.94, P<0.001), heart failure (3.34, 0.71 to 5.97, P<0.01), and ex-smoker status (3.01, 0.94 to 5.07, P=0.002), but decreased with older age (─0.19, ─0.37 to ─0.02, P=0.03). CONCLUSION: Restricting breathlessness increased in this elderly population in the months preceding death from any cause. Breathlessness should be assessed and managed in the context of poor prognosis