String Necklaces and Primordial Black Holes from Type IIB Strings

We consider a model of static cosmic string loops in type IIB string theory, where the strings wrap cycles within the internal space. The strings are not topologically stabilised, however the presence of a lifting potential traps the windings giving rise to kinky cycloops. We find that PBH formation occurs at early times in a small window, whilst at late times we observe the formation of dark matter relics in the scaling regime. This is in stark contrast to previous predictions based on field theoretic models. We also consider the PBH contribution to the mass density of the universe, and use the experimental data to impose bounds on the string theory parameters.Comment: 45 pages, 9 figures, LaTeX; published versio

Climate change and food security: health impacts in developed countries.

BACKGROUND: Anthropogenic climate change will affect global food production, with uncertain consequences for human health in developed countries. OBJECTIVES: We investigated the potential impact of climate change on food security (nutrition and food safety) and the implications for human health in developed countries. METHODS: Expert input and structured literature searches were conducted and synthesized to produce overall assessments of the likely impacts of climate change on global food production and recommendations for future research and policy changes. RESULTS: Increasing food prices may lower the nutritional quality of dietary intakes, exacerbate obesity, and amplify health inequalities. Altered conditions for food production may result in emerging pathogens, new crop and livestock species, and altered use of pesticides and veterinary medicines, and affect the main transfer mechanisms through which contaminants move from the environment into food. All these have implications for food safety and the nutritional content of food. Climate change mitigation may increase consumption of foods whose production reduces greenhouse gas emissions. Impacts may include reduced red meat consumption (with positive effects on saturated fat, but negative impacts on zinc and iron intake) and reduced winter fruit and vegetable consumption. Developed countries have complex structures in place that may be used to adapt to the food safety consequences of climate change, although their effectiveness will vary between countries, and the ability to respond to nutritional challenges is less certain. CONCLUSIONS: Climate change will have notable impacts upon nutrition and food safety in developed countries, but further research is necessary to accurately quantify these impacts. Uncertainty about future impacts, coupled with evidence that climate change may lead to more variable food quality, emphasizes the need to maintain and strengthen existing structures and policies to regulate food production, monitor food quality and safety, and respond to nutritional and safety issues that arise

Marine biodiversity in the Caribbean UK overseas territories: Perceived threats and constraints to environmental management

Islands are often considered to be a priority for conservation, because of their relatively high levels of biodiversity and their vulnerability to a range of natural and anthropogenic threats. However, the capacity of islands to conserve and manage biodiversity may depend upon their governance structures. Many island states are affiliated to other countries through an 'overseas territory' status, which may provide them with access to resources and support mechanisms, but which may also influence the capacity for local-scale management of environmental issues. The United Kingdom has 12 island Overseas Territories (UKOTs), most of which support biodiversity of high conservation concern. This study investigates perceptions of current and future threats to marine ecosystems and constraints to environmental protection on the six Caribbean UKOTs, through semi-structured interviews with officials from UK and UKOT government departments and non-governmental organisations. Coastal development, pollution and over-fishing were perceived as threats of most concern for the next decade, but climate change was perceived as by far the greatest future threat to the islands' marine ecosystems. However, a series of common institutional limitations that currently constrain mitigation and conservation efforts were also identified, including insufficient personnel and financial support, a lack of long-term, sustainable projects for persistent environmental problems and inadequate environmental legislation. These findings highlight the need for regional cooperation and capacity-building throughout the Caribbean and a more concerted approach to an UKOT environmental management by the UK and UKOTs' governments.Marine management Management constraints UK overseas territories Perceptions Marine biodiversity threats Climate change

Future deforestation drivers in an Amazonian ranching frontier

In the Brazilian Amazonia, extensive and durable deforestation is led by ranching profits and increased demand for meat in large, globalized markets. A closer look at the arc of deforestation in southern Amazonia shows deforestation moving northward from ranching hotspots into surrounding frontiers as roads are opened. In the case of the Alta Floresta frontier, however, the road network has become dense enough that topographic features (land flatness and land away from river flooding plains) are now the significant risk factors of forest loss. Conversely, riparian corridors seem to be avoided by deforestation, as water and shade are vital for cattle weight gain or the corridors are waterlogged. Local interactions, expressed as spatial autocorrelation in multivariate models or neighbors in cellular automata forecasts, are also significant. In the short run, these local interactions produce a pattern of irreversible edge deforestation around pastures and fragmentation. But in the long run, spillovers outside of the study area can be expected as a result of economic momentum and the exhaustion of cattle-suitable areas in Alta Floresta

Applying Geographical Information Systems (GIS) to Environmental and Resource Economics

Many of the analyses undertaken byenvironmental and resource economics areintimately concerned with spatial variations.This article examines the contribution whichGeographical Information Systems (GIS) mayprovide in incorporating the complexities ofthe spatial dimension within such analyses. Thepaper introduces the reader to the types ofdata handled by a GIS and overviews thepractical functionality offered by suchsystems. A brief literature review issupplemented by a number of more detailedapplications illustrating various GIStechniques which may be of use to the appliedenvironmental or resource economist. Copyright Kluwer Academic Publishers 2002benefit transfer, environmental economics, Geographical Information System (GIS), resource economics, spatial analysis, valuation,