In this study we estimate urban traffic flow using GPS-enabled taxi trajectory data in Qingdao, China, and examine the capability of the betweenness centrality of the street network to predict traffic flow. The results show that betweenness centrality is not a good predictor variable for urban traffic flow, which has, theoretically, been pointed out in existing literature. With a critique of the betweenness centrality as a predictor, we further analyze the characteristics of betweenness centrality and point out the ‘gap’ between this centrality measure and actual flow. Rather than considering only the topological properties of a street network, we take into account two aspects, the spatial heterogeneity of human activities and the distance-decay law, to explain the observed traffic-flow distribution. The spatial distribution of human activities is estimated using mobile phone Erlang values, and the power law distance decay is adopted. We run Monte Carlo simulations to generate trips and predict traffic-flow distributions, and use a weighted correlation coefficient to measure the goodness of fit between the observed and the simulated data. The correlation coefficient achieves the maximum (0.623) when the exponent equals 2.0, indicating that the proposed model, which incorporates geographical constraints and human mobility patterns, can interpret urban traffic flow well.

ObjectivesAlthough detecting breast cancer at an early stage through screening has been clearly shown to be an effective strategy, the screening participation rate in China remains low. This systematic review sought to synthesise the current evidence to identify factors associated with breast cancer screening participation among women in mainland China.DesignThis study was a systematic review.Data sourcesStudies were collected from PubMed, PsycINFO, CINAHL, EMBASE and three major Chinese databases, specially China National Knowledge Infrastructure, Chongqing VIP and Wanfang Data.Eligibility criteriaAll included papers were original research studies with a longitudinal or cross-sectional study design that considered associated factors of breast cancer screening participation among women in mainland China.Data extraction and synthesisStudy selection, data extraction and quality assessment were conducted independently by two reviewers, involving a third to help reach a consensus when necessary. Primary outcomes of interest included factors associated with breast cancer screening participation.ResultsA total of 19 studies were included in this review. Based on these studies, geographical region, a personal history of breast disease, past screening behaviours for breast disease, physical examination and the availability of medical specialists/equipment for breast examination were consistently associated with participation in breast cancer screening, while residential area, ethnicity and attitude towards breast cancer screening appeared to be associated with participation in breast cancer screening. There were additionally some factors with even more limited evidence with which to ascertain their association with screening participation.ConclusionsThere exists a wide range of factors that influence breast cancer screening participation in mainland China. These findings could help to inform future research and policy efforts.

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