Adaptive dynamics and the implementation problem with complete information

This paper studies the equilibrating process of several implementationmechanisms using naive adaptive dynamics. We show that the dynamics convergeand are stable, for the canonical mechanism of implementation in Nash equilibrium.In this way we cast some doubt on the criticism of ``complexity'' commonlyused against this mechanism. For mechanisms that use more refined equilibrium concepts,the dynamics converge but are not stable. Some papers in the literatureon implementation with refined equilibrium concepts have claimed that themechanisms they propose are ``simple'' and implement ``everything'' (incontrast with the canonical mechanism). The fact that some of these ``simple''mechanisms have unstable equilibria suggests that these statements shouldbe interpreted with some caution.

Taking "Galton's problem" Seriously : Towards a Theory of Policy Diffusion

This article builds on the recent policy diffusion literature and attempts to overcome one of its major problems, namely the lack of a coherent theoretical framework. The literature defines policy diffusion as a process where policy choices are interdependent, and identifies several diffusion mechanisms that specify the link between the policy choices of the various actors. As these mechanisms are grounded in different theories, theoretical accounts of diffusion currently have little internal coherence. In this article we put forward an expected-utility model of policy change that is able to subsume all the diffusion mechanisms. We argue that the expected utility of a policy depends on both its effectiveness and the payoffs it yields, and we show that the various diffusion mechanisms operate by altering these two parameters. Each mechanism affects one of the two parameters, and does so in distinct ways. To account for aggregate patterns of diffusion, we embed our model in a simple threshold model of diffusion. Given the high complexity of the process that results, strong analytical conclusions on aggregate patterns cannot be drawn without more extensive analysis which is beyond the scope of this article. However, preliminary considerations indicate that a wide range of diffusion processes may exist and that convergence is only one possible outcome.

Variation in performance across Swiss mammography screening programmes: the influence of reading strategy and experience.

[Abstract] Reading volume and mammography screening performance appear positively correlated. Performance was compared across organised Swiss screening programmes, which target relatively small populations. Except for accreditation of 2nd readers radiologists (restrictive vs non-restrictive strategy), Swiss programmes have similar screening regimen/procedures and duration, which maximises comparability. Variation in performance was explored in order to improve mammography practice and optimise screening performance. Indicators of quality and effectiveness were evaluated for about 200,000 screens performed over 4 screening rounds in the 3 longest-standing Swiss cantonal programmes (of Vaud, Geneva and Valais). Interval cancers were identified by linkage with cancer registries records. Most European standards of performance were met with a favourable cancer stage shift. Several performance indicators showed substantial variation across programmes. In subsequent rounds, compared with programmes (Vaud and Geneva) which accredited few 2nd readers to increase their individual reading volume, proportions of in situ lesions and of small cancers (? 1cm) were one third lower and halved, respectively, and the proportion of advanced lesions (stage II+) nearly 50% higher in the programme without a restrictive selection strategy. Discrepancy in second-year proportional incidence of interval cancers appears to be multicausal. Differences in performance could partly be explained by a selective strategy for 2nd readers and a prior experience in service screening, but not by the levels of opportunistic screening and programme attendance. This study provides clues for enhancing mammography screening performance in low-volume Swiss programmes.

Dispersal probability distributions and the wave-front speed problem

The speed and width of front solutions to reaction-dispersal models are analyzed both analytically and numerically. We perform our analysis for Laplace and Gaussian distribution kernels, both for delayed and nondelayed models. The results are discussed in terms of the characteristic parameters of the models

Zum Problem der Übersetzung von Gedichten : auch vom Gesichtspunkt des Computers

Abstract

Note on the blocking flow shop problem

We present some results attained with different algorithms for the Fm|block|Cmax problem using as experimental data the well-known Taillard instances.

Iowa Problem Identification, February 2010

Each year, traffic crashes in the United States result in nearly 300,000 deaths and serious injuries. In 2008 alone, traffic crashes cost the nation an estimated $230 billion, nine times more than the estimated cost of all crime. Highway crashes represent the leading cause of death and disabling injury for persons under age 35. In recognition of this problem, the Congress of the United States enacted national highway safety legislation in 1966, which led to the establishment of the National Highway Traffic Safety Administration (NHTSA). The legislation also provided for federal highway safety monies to be made available to the states with a goal of reducing death and injury on the nation’s roads. Iowa has been very active in the federal-state local highway safety partnership since the mid 1960s.

Alcohol consumption in late adolescence and early adulthood - where is the problem?

Risky single-occasion drinking (RSOD) is more common in late adolescence and early adulthood (approximately between the ages of 16 and 30) than in any other period in life. This is also the age when young people in Switzerland and many other European countries are legally allowed to buy and drink alcohol, but they usually do not yet have adult responsibilities. This paper reviews evidence from the international literature and provides examples of studies conducted in Switzerland demonstrating that (a) RSOD is by far most prevalent on Saturday evenings followed by Friday evenings, usually because young people go out and do not have any work or study responsibilities the next day; (b) RSOD results from drinking in private before going out ("predrinking") and accelerating the pace of drinking (i.e. increasing the number of drinks consumed per hour); (c) RSOD is often not accidental but purposeful,. to seek excitement, to have fun and to feel the effects of alcohol; (d) RSOD occurs predominantly outside the home, mostly in bars, pubs, discos or at special events and festivals; (e) RSOD often results in intended and unintended injuries and other acute consequences, which are leading risk factors for mortality and morbidity in this age group. Effective prevention strategies should include attempts to reduce opportunities to engage in heavy drinking as well as strategies to reduce its harmful consequences.