A Comparison of Three Child OHRQoL Measures.

Comparing oral health-related quality of life (OHRQoL) measures can facilitate selecting the most appropriate one for a particular research question/setting. Three child OHRQoL measures Child Perceptions Questionnaire (CPQ11⁻14), the Child Oral Health Impact Profile (COHIP) and the Caries Impacts and Experiences Questionnaire for Children (CARIES-QC) were used with 335 10- to 13-year-old participants in a supervised tooth-brushing programme in New Zealand. The use of global questions enabled their validity to be examined. Assessments were conducted at baseline and after 12 months. All three measures had acceptable internal consistency reliability. There were moderate, positive correlations among their scores, and all showed differences in the impact of dental caries on OHRQoL, with children with the highest caries experience having the highest scale scores. Effect sizes were used to assess meaningful change. The CPQ11⁻14 and the CARIES-QC showed meaningful change. The COHIP-SF score showed no meaningful change. Among children reporting improved OHRQoL, baseline and follow-up scores differed significantly for the CPQ11⁻14 and CARIES-QC measures, although not for the COHIP-SF. The three scales were broadly similar in their conceptual basis, reliability and validity, but responsiveness of the COHIP-SF was questionable, and the need to compute two different scores for the CARIES-QC meant that its administrative burden was considerably greater than for the other two measures. Replication and use of alternative approaches to measuring meaningful change are suggested

The spread of epidemic disease on networks

The study of social networks, and in particular the spread of disease on networks, has attracted considerable recent attention in the physics community. In this paper, we show that a large class of standard epidemiological models, the so-called susceptible/infective/removed (SIR) models can be solved exactly on a wide variety of networks. In addition to the standard but unrealistic case of fixed infectiveness time and fixed and uncorrelated probability of transmission between all pairs of individuals, we solve cases in which times and probabilities are non-uniform and correlated. We also consider one simple case of an epidemic in a structured population, that of a sexually transmitted disease in a population divided into men and women. We confirm the correctness of our exact solutions with numerical simulations of SIR epidemics on networks.Comment: 12 pages, 3 figure

Approximation Algorithms for Edge-Disjoint Paths and Unsplittable Flow

Abstract. In the maximum edge-disjoint paths problem (MEDP) the input consists of a graph and a set of requests (pairs of vertices), and the goal is to connect as many requests as possible along edge-disjoint paths. We give a survey of known results about the complexity and approxima-bility of MEDP and sketch some of the main ideas that have been used to obtain approximation algorithms for the problem. We consider also the generalization of MEDP where the edges of the graph have capaci-ties and each request has a profit and a demand, called the unsplittable flow problem