Spikes in the Mixmaster regime of G_2 cosmologies

We produce numerical evidence that spikes in the Mixmaster regime of G_2 cosmologies are transient and recurring, supporting the conjecture that the generalized Mixmaster behavior is asymptotically non-local where spikes occur. Higher order spike transitions are observed to split into separate first order spike transitions.Comment: Minor corrections. Matches the published versio

Hadrons Without Strings

Descriptions of hadrons and glueballs can be constructed using strings to preserve gauge invariance. We show how this string dependence may be removed to all orders in perturbation theory.Comment: 11 pages, 3 figures, LaTe

Increasing the demand for childhood vaccination in developing countries: a systematic review

This article provides a systematic review of 60 studies of evidence for improving routine vaccination programs in developing countries. Mass media campaigns may be effective, but the impact depends on access to media and may be costly if run at a local level. Interventions to increase demand for routine childhood vaccination have not been adequately investigated. Collateral-free credit to poor women may improve their autonomy and capacity to care for their families, including vaccination. However, attempts to maintain or increase deteriorating vaccination coverage almost all focus on supply side interventions: improving availability and delivery of vaccines

Understanding the friction of atomically thin layered materials

Friction is a ubiquitous phenomenon that greatly affects our everyday lives and is responsible for large amounts of energy loss in industrialised societies. Layered materials such as graphene have interesting frictional properties and are often used as (additives to) lubricants to reduce friction and protect against wear. Experimental Atomic Force Microscopy studies and detailed simulations have shown a number of intriguing effects such as friction strengthening and dependence of friction on the number of layers covering a surface. Here, we propose a simple, fundamental, model for friction on thin sheets. We use our model to explain a variety of seemingly contradictory experimental as well as numerical results. This model can serve as a basis for understanding friction on thin sheets, and opens up new possibilities for ultimately controlling their friction and wear protection.Comment: 8 pages, 6 figures, publication pendin

Individual Carbon Footprint Reduction: Evidence from Pro-environmental Users of a Carbon Calculator

We provide the first estimates of how pro-environmental consumers reduce their total carbon footprint using a carbon calculator that covers all financial transactions. We use data from Swedish users of a carbon calculator that includes weekly estimates of users’ consumption-based carbon-equivalent emissions based on detailed financial statements, official registers, and self-reported lifestyle factors. The calculator is designed to induce behavioral change and gives users detailed information about their footprint. By using a robust difference-in-differences analysis with staggered adoption of the calculator, we estimate that users decrease their carbon footprint by around 10% in the first few weeks, but over the next few weeks, the reduction fades. Further analysis suggests that the carbon footprint reduction is driven by a combination of a shift from high- to low-emitting consumption categories and a temporary decrease in overall spending, and not by changes in any specific consumption category

Measuring the direct and indirect effects of low-carbon lifestyles using financial transactions

This study investigates the net effect of four low-carbon lifestyle options that could potentially be adopted by many individuals and households to achieve substantial cuts in greenhouse gas emissions: not owning a car, not flying, not living in a detached house, and having a vegan diet. We evaluated the direct and indirect effects of these options on the carbon footprints of a sample of 715 individuals. Their emissions were calculated using a carbon calculator app that estimates the footprint associated with their consumption, based on financial transaction data from their bank(s) in combination with a lifestyle survey and data from official databases. This data also provides the basis for a detailed analysis of how differences in spending and greenhouse gas emissions in one consumption domain can rebound and/or spillover into other domains. Our results show that these four lifestyle options are associated with substantial net emission reductions, ranging from 0.5 to 1.5 tonnes of CO2eq/cap/yr each. The results also suggest that, contrary to the theory of economic rebound effects, the indirect effects of these practices are related to further emission reductions in other consumption domains, except for people who do not fly, for whom we saw a very limited rebound effect. The sample has on average relatively strong pro-environmental personal norms, which limits the generalizability of the results and calls for further research