Network Meta-analysis White, Ian R.
The Stata journal,
12/2015, Letnik:
15, Številka:
4
Journal Article
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Network meta-analysis is a popular way to combine results from several studies (usually randomized trials) comparing several treatments or interventions. It has usually been performed in a Bayesian ...setting, but recently it has become possible in a frequentist setting using multivariate meta-analysis and meta-regression, implemented in Stata with mvmeta. I describe a suite of Stata programs for network meta-analysis that perform the necessary data manipulation, fit consistency and inconsistency models using mvmeta, and produce various graphics.
During an epidemic, metrics such as R0, doubling time, and case fatality rates are important in understanding and predicting the course of an epidemic. However, if collected over country or regional ...scales, these metrics hide important smaller-scale, local dynamics. We examine how commonly used epidemiological metrics differ for each individual state within the United States during the initial COVID-19 outbreak. We found that the detected case number and trajectory of early detected cases differ considerably between states. We then test for correlations with testing protocols, interventions and population characteristics. We find that epidemic dynamics were most strongly associated with non-pharmaceutical government actions during the early phase of the epidemic. In particular, early social distancing restrictions, particularly on restaurant operations, was correlated with increased doubling times. Interestingly, we also found that states with little tolerance for deviance from enforced rules saw faster early epidemic growth. Together with other correlates such as population density, our results highlight the different factors involved in the heterogeneity in the early spread of COVID-19 throughout the United States. Although individual states are clearly not independent, they can serve as small, natural experiments in how different demographic patterns and government responses can impact the course of an epidemic.
Simulation studies are computer experiments that involve creating data by pseudo‐random sampling. A key strength of simulation studies is the ability to understand the behavior of statistical methods ...because some “truth” (usually some parameter/s of interest) is known from the process of generating the data. This allows us to consider properties of methods, such as bias. While widely used, simulation studies are often poorly designed, analyzed, and reported. This tutorial outlines the rationale for using simulation studies and offers guidance for design, execution, analysis, reporting, and presentation. In particular, this tutorial provides a structured approach for planning and reporting simulation studies, which involves defining aims, data‐generating mechanisms, estimands, methods, and performance measures (“ADEMP”); coherent terminology for simulation studies; guidance on coding simulation studies; a critical discussion of key performance measures and their estimation; guidance on structuring tabular and graphical presentation of results; and new graphical presentations. With a view to describing recent practice, we review 100 articles taken from Volume 34 of Statistics in Medicine, which included at least one simulation study and identify areas for improvement.
This unique study of social harm offers a systematic and critical discussion of the nature of environmental harm from an eco-justice perspective, challenging conventional criminological definitions ...of environmental harm.
The book evaluates three interconnected justice-related approaches to environmental harm: environmental justice (humans), ecological justice (the environment) and species justice (non-human animals). It provides a critical assessment of environmental harm by interrogating key concepts and exploring how activists and social movements engage in the pursuit of justice. It concludes by describing the tensions between the different approaches and the importance of developing an eco-justice framework that to some extent can reconcile these differences.
Using empirical evidence built on theoretical foundations with examples and illustrations from many national contexts, 'Environmental harm' will be of interest to students and academics in criminology, sociology, law, geography, environmental studies, philosophy and social policy all over the world.
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•The carbon market is growing.•Four carbon offset methodologies have been approved for wetland restoration.•Very few wetland restoration carbon offsets transected to ...date.•Simplification of existing methodologies may facilitate adoption of blue C offsets.
Coastal wetlands have been valued for a variety of ecosystem services including carbon sequestration and long term storage. The carbon sequestered and stored in coastal habitat including mangroves, salt marshes, and seagrass beds is termed as blue carbon. However, these systems are threatened mainly due to sea level rise, limited sediment supply, edge erosion, and anthropogenic influences. These habitats require restoration and conservation to continue providing ecosystem services. The incentive for emission reductions, referred to as carbon offsets, is well established for other ecosystems like forestry and agriculture. Some blue carbon offset methodologies or protocols have been certified by various voluntary carbon markets; however to date, a few wetland restoration carbon offset in the US has been transacted. Thus, the goal of this paper is to discuss the existing carbon market and carbon market methodologies applicable to coastal wetland restoration and conservation in the US. Currently, four wetland carbon offset methodologies have been approved in the carbon market. These methodologies are site and/or project-specific depending on the type of the wetlands, vulnerability to loss, and restoration need. The appropriate carbon stock and Green House Gas (GHG) emission assessment is the basis of determining carbon offsets. Simplification of the existing methodologies and development of new site and project-specific methodologies could potentially help to realize blue carbon offsets in practice. The slowly growing demand for carbon offsets in the carbon market could potentially be fulfilled from the blue carbon pool. While this carbon offset is in the early stages, this review may help the inclusion of carbon offset component in the coastal restoration and conservation projects in United States and potentially across the globe.
Abstract
Food production, sustainable development, population growth, and agricultural environmental impacts are linked global problems that require complex solutions. Many efforts evaluating these ...challenges primarily evaluate dietary strategies designed for health and environmental objectives without considering the subsequent adaptations required by the global food supply. Here we use a complementary approach to summarize trends and variability in the current agricultural system in the context of the growing population and impending environmental challenges. Globally, agricultural systems produce sufficient nutrients to feed 10 billion people with the exception of Ca, DHA + EPA, vitamins B4, D, and E. In a network analysis, greenhouse gas emissions were conditionally dependent on ruminant meat and milk, while water use was conditionally dependent on vegetable and fruit production; however, supplies of most nutrients were also dependent on these same production categories, suggesting trade-offs between nutritional and environmental objectives. Future work should evaluate strategies to address these compromises (i.e., improving water use efficiency and reducing greenhouse gas emissions), to explore to what extent such compromises are biophysically essential or merely a product of the current agricultural system structures. Given the time-sensitive nature of population growth and environmental concerns, strategies to make more effective use of currently produced agricultural products will also be critical complementary strategies to sustainably feed the growing population which can work in concert with other agricultural-, diet- and policy-focused efforts.
Phenotypic characteristics of animals can change independently from changes in the genetic code. These plastic phenotypic responses are important for population persistence in changing environments. ...Plasticity can be induced during early development, with persistent effects on adult phenotypes, and it can occur reversibly throughout life (acclimation). These manifestations of plasticity have been viewed as separate processes. Here we argue that developmental conditions not only change mean trait values but also modify the capacity for acclimation. Acclimation counteracts the potentially negative effects of phenotype–environment mismatches resulting from epigenetic modifications during early development. Developmental plasticity is therefore also beneficial when environmental conditions change within generations. Hence, the evolution of reversible acclimation can no longer be viewed as independent from developmental processes.
Phenotypic plasticity increases resilience to environmental change.
Developmental conditions determine capacity for reversible acclimation later in life.
This mechanistic link between development and acclimation means that the costs of plasticity are reduced.
Evolutionary models can incorporate this link explicitly to improve predictions.
We introduce a class of states, called minimally entangled typical thermal states, designed to resemble a typical state of a quantum system at finite temperature with a bias towards classical ...(minimally entangled) properties. These states reveal in an intuitive way properties such as short-range order which may often be hidden. A finite-T density matrix renormalization group algorithm is presented which is only modestly slower than the T=0 density matrix renormalization group.
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