Irrational behavior in the Brown - von Neuman - Nash dynamics

We present a class of games with a pure strategy being strictly dominated by an- other pure strategy such that the former survives along solutions of the Brown - von Neumann - Nash dynamics from an open set of initial conditions

Dynamic Modelling of Child Mortality in Developing Countries: Application for Zambia

In this paper, we analyse the causes of under five mortality in Zambia, with a particular emphasis on assessing possible time-variations in the effects of covariates, i.e. whether the effects of certain covariates vary with the age of the child. The analysis is based on micro data from the 1992 Demographic and health Survey. Employing a Bayesian dynamic logit model for discrete time survival data and Markov-Chain Monte Carlo methods, we find that there are several variables, including the age of the mother and the breastfeeding duration whose effects exhibit distinct age-dependencies. In the case of breastfeeding, this age dependency is intimately linked with the reasons for stopping breastfeeding. Incorporating such age dependencies greatly improves the explanatory power of the model and yields new insights on the differential role of covariates on child survival

The impact of retirement on physical activity

Most adults do not achieve the levels of physical activity currently recommended for a healthy lifestyle. Population surveys suggest that there is a linear decline of activity levels with age, yet physical activity has many health benefits for older adults. If these are to be more widely adopted among older people, health policy and promotion require an understanding of the factors that influence decreasing activity with age. This study examined the patterns of physical activity of 699 participants in the West of Scotland Twenty-07 Study who were aged 60 years when interviewed in 1991 and followed up four to five years later. It examined the factors that influenced whether or not the subjects achieved currently recommended levels of activity, by applying random effects models with a seasonal adjustment. It was found that higher levels of physical activity associated with a healthier lifestyle, and that socio-economic factors played a minor role in determining the level of physical activity. A substantial amount of physical activity occurred at work but was lost by those who had retired, for while those who were not working were more physically active at home or at leisure than those in work, the majority of the sample did too little physical activity outside work to compensate for the loss of work-based activity. One conclusion is that health promotion initiatives that encourage people to become more physically active should be targeted at those who are about to retire

Top Quark Properties in Little Higgs Models

We study the shifts in the gauge couplings of the top quark induced in the Littlest Higgs model with and without T parity. We find that the ILC will be able to observe the shifts throughout the natural range of model parameters.Comment: 3 pages, 4 figures. Contributed to 2005 International Linear Collider Physics and Detector Workshop and 2nd ILC Accelerator Workshop, Snowmass, Colorado, 14-27 Aug 200

Best Response Adaptation for Role Games

Consider a large population of individuals which can be in one of two distinct roles. The role of the individual is switched every now and then, and interactions occur between randomly paired individuals in different roles. These interactions are represented by a bimatrix game and individuals are modeled as boundedly rational expected utility maximizers who choose their actions according to a myopic best response rule. The resulting dynamics of the population state is given by a system of differential equations and differential inclusions. If the bimatrix game is zero-sum, the population state converges to a fixed point set corresponding to the set of Nash equilibria of this game. Moreover, if the zero-sum game has a unique Nash equilibrium, the global attractor of the population state is a unique and explicitly computable fixed point, even if the set of fixed points is a continuum (which is the case, if the unique Nash equilibrium is completely mixed). This global attractor does neither depend on the rates of role switching and strategy reviewing, nor on the relative size of the two subpopulations of individuals in different roles

The Association between Vitamin D Receptor Expression and Prolonged Overall Survival in Breast Cancer.

Summary In this study, we analyzed vitamin D receptor (VDR) expression and survival in a breast cancer patient cohort of 82 breast cancer patients. Immunohistochemical analysis was possible in 91.5% of the patients (75/82). Staining was evaluated using the semi-quantitative assay according to Remmele and Stegner (immunoreactivity score [IRS]). IRS 0–1 was negative/very low, IRS 2–4 was moderate to high, and IRS 6–12 was high. Statistical analysis was performed by Spearman’s correlation test (p<0.05 significant). Overall survival was analyzed using Kaplan-Meier estimations. Only 6 patients had a negative IRS. Moderate IRS values were present in 20 patients. Most of the patients had a high IRS (49). For survival analysis, data were dichotomized (IRS 0–4: negative to moderate and IRS 6–12: high VDR expression). In univariate analysis, VDR expression showed significant differences in progression-free survival (PFS) and overall survival (OS). Patients with high IRS scores showed significantly better PFS and OS than patients with moderate/negative IRS scores for VDR expression. Tumor size was significantly correlated to PFS. When analyzed separately, the three different IRS groups showed significant differences in VDR expression. The present data suggest that VDR expression in breast cancer tissue may be of clinical significance, and the results provide evidence that VDR may be a factor with prognostic relevance. (J Histochem Cytochem 60:121–129, 2012). Keywords: breast cancer, vitamin D receptor, immunohistochemistry, prognosi

A Smooth Test in Proportional Hazard Survival Models using Local Partial Likelihood Fitting

Proportional hazard models for survival data, even though popular and numerically handy, suffer from the restrictive assumption that covariate effects are constant over survival time. A number of tests have been proposed to check this assumption. This paper contributes to this area by employing local estimates allowing to fit hazard models with covariate effects smoothly varying with time. A formal test is derived to test the model with proportional hazards against the smooth general model as alternative. The test proves to possess omnibus power. Comparative simulations and two data examples accompany the presentation. Extensions are provided to multiple covariate settings, where the focus of interest is to decide which of the covariate effects vary with time

Computational interpretations of analysis via products of selection functions

We show that the computational interpretation of full comprehension via two wellknown functional interpretations (dialectica and modified realizability) corresponds to two closely related infinite products of selection functions

A Modified Version of the Waxman Algorithm

The iterative algorithm recently proposed by Waxman for solving eigenvalue problems, which relies on the method of moments, has been modified to improve its convergence considerably without sacrificing its benefits or elegance. The suggested modification is based on methods to calculate low-lying eigenpairs of large bounded hermitian operators or matrices

An algorithmic approach to the existence of ideal objects in commutative algebra

The existence of ideal objects, such as maximal ideals in nonzero rings, plays a crucial role in commutative algebra. These are typically justified using Zorn's lemma, and thus pose a challenge from a computational point of view. Giving a constructive meaning to ideal objects is a problem which dates back to Hilbert's program, and today is still a central theme in the area of dynamical algebra, which focuses on the elimination of ideal objects via syntactic methods. In this paper, we take an alternative approach based on Kreisel's no counterexample interpretation and sequential algorithms. We first give a computational interpretation to an abstract maximality principle in the countable setting via an intuitive, state based algorithm. We then carry out a concrete case study, in which we give an algorithmic account of the result that in any commutative ring, the intersection of all prime ideals is contained in its nilradical