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The aim of this meta-analysis and systematic review is to summarize and critically analyze the influence of surgery-related factors in lumbar interbody fusion for degenerative spine diseases. A systematic review of the literature was carried out with a primary search being performed on Medline through PubMed. The 2009 PRISMA flowchart and checklist were taken into account. Sixty-seven articles were included in the analysis: 48 studies were level IV of evidence, whereas 19 were level III. All interbody fusion techniques analyzed have proved to reach a good fusion rate. An overall mean fusion rate of 93% (95% CI 92–95%, p

This paper analyses factors that contributed to the evolution of SO2, NOx and CO2 emissions in Europe from 1960 to 2010. Historical energy balances, along with population and economic growth data, are used to quantify the impacts of major determinants of changing emission levels, including energy intensity, conversion efficiency, fuel mix, and pollution control. Time series of emission levels are compared for countries in Western and Eastern Europe, throwing light on differences in the importance of particular emissiondriving forces. Three quarters of the decline in SO2 emissions in Western Europe resulted from a combination of reduced energy intensity and improved fuel mix, while dedicated endof- pipe abatement measures played a dominant role in the reduction of NOx emissions. The increase in atmospheric emissions in Eastern Europe through the mid-1990s was associated with the growth of energy-intensive industries, which off-setted the positive impact of better fuel quality and changes in fuel mix. A continuous decrease in energy intensity and higher conversion efficiencies have been the main factors responsible for the moderate rate of growth of European CO2 emissions.

The world is undergoing a massive urban transition, which is now both the greatest driver of global environmental change and the most significant influence on human health. Cities offer real opportunities for improving health, but managed poorly, they can also create or reinforce significant health deficits while putting severe stresses on the natural systems which support human civilization. Management of urban problems is rarely straightforward, as complexity across scales and sectors, in causal structures, actors and incentives, can lead to ineffective policies and unintended consequences. Systems thinking offers a promising way forward in its ability to deal with non-linear relationships and simultaneous actions and outcomes. Encompassing, on the one hand, analytic frameworks and methods that can provide important causal insights and a test bed for urban policy, and on the other, broad processes of inter- and trans-disciplinary engagement to better define problems and feasible solutions, systems approaches are critical to the current and future design and management of sustainable healthy cities.

Malaria occurrence is lower in urban versus rural areas of sub-Saharan Africa for a variety of reasons, including limitation of suitable mosquito habitat, generally improved housing standards and access to prevention and treatment, and a relative decrease in the ratio of vectors to humans. Nonetheless, empirical observation confirms that malaria cases, whether locally transmitted or imported, are frequently observed in cities in endemic areas. Theoretical considerations imply that local transmission will decrease as a city grows, transitioning from a relatively malaria-permissive state to one that encourages reduction or extinction. Using a simple deterministic systems dynamic model based on traditional malaria models, we simulate scenarios for the evolution of local transmission rates and acquired immunity in a homogenous urban area with respect to population size, growth rate, and level of suppression of mosquito breeding. In particular, we consider how the timing and extent of decreases in local transmission are mitigated by travel by city dwellers to endemic rural areas and their resulting exposure to infected mosquitoes. We explore the generalizability and sensitivity to assumptions of our results using microsimulation and analytic methods to account for various aspects of environmental (urban/rural) and demographic heterogeneity. The results of these simulation models should inform projections for long-term urban malaria trends, and have implications for the targeting of malaria prevention efforts in urban and peri-urban areas of sub-Saharan Africa.