Public Health Impacts of Climate Change

According to the Intergovernmental Panel on Climate Change (IPCC), the leading scientific institution on climate change research, atmospheric concentration of carbon dioxide, the greenhouse gas most attributed to causing climate change, has increased by 31 percent since the 1750s. This increase is caused by human activities, primarily the burning of fossil fuels. As a result of increasing carbon dioxide and other greenhouse gas emissions, changes in the earth's climate have been observed. The IPCC has stated that the 1990s was the warmest decade on record, with 1998 being the warmest year since 1861, before which adequate data is lacking. It has been recorded that the global average temperature has increased by 0.6 degrees Celsius in the past century and has been accompanied by observed sea level rise. Severe weather events, like El Nino, have also become more frequent in the past decades as a result of the changing climate. Based on these past and current trends, scientists have forecasted likely future climate conditions. It has been predicted that, among other things, regional weather patterns will likely be altered,changes in global precipitation patterns will occur, an increase of severe weather events is probable, and a general shift of climate conditions to higher latitudes will result. These climatic changes, already being witnessed today, will have a significant impact on human existence. Even slight alterations in climate conditions have the potential to greatly alter society

Freedom of Information versus National Sovereignty: The Need for a New Global Forum for the Resolution of Transborder Date Flow Problems

This Note argues that the issues raised by transborder data flow restrictions must be dealt with on a global scale, not on a national basis. Part I of this Note discusses the international legal principles underlying the concept of freedom of information and the legal difficulties presented by the imposition of transborder data flow restrictions. Part II analyzes the perception among developing nations that sovereign rights are threatened by an unrestricted flow of information and discusses the measures developing nations are implementing to control this perceived threat. Part III analyzes several approaches suggested for dealing with the problems of transborder data flow restrictions and argues that a new international forum must be created to constructively address the legitimate concerns of the developing nations. This Note concludes that since the effective demise of Unesco, progress must be made toward creating a viable international forum to address the multilateral concerns over transborder data flow restrictions

Switched networks with maximum weight policies: Fluid approximation and multiplicative state space collapse

We consider a queueing network in which there are constraints on which queues may be served simultaneously; such networks may be used to model input-queued switches and wireless networks. The scheduling policy for such a network specifies which queues to serve at any point in time. We consider a family of scheduling policies, related to the maximum-weight policy of Tassiulas and Ephremides [IEEE Trans. Automat. Control 37 (1992) 1936--1948], for single-hop and multihop networks. We specify a fluid model and show that fluid-scaled performance processes can be approximated by fluid model solutions. We study the behavior of fluid model solutions under critical load, and characterize invariant states as those states which solve a certain network-wide optimization problem. We use fluid model results to prove multiplicative state space collapse. A notable feature of our results is that they do not assume complete resource pooling.Comment: Published in at http://dx.doi.org/10.1214/11-AAP759 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

International Migration and Household Agricultural Production Decisions: The Case of El Salvador

Replaced with revised version of paper 07/23/07.Farm Management,

Medial/skeletal linking structures for multi-region configurations

We consider a generic configuration of regions, consisting of a collection of distinct compact regions $\{\Omega_i\}$ in $\mathbb{R}^{n+1}$ which may be either smooth regions disjoint from the others or regions which meet on their piecewise smooth boundaries $\mathcal{B}_i$ in a generic way. We introduce a skeletal linking structure for the collection of regions which simultaneously captures the regions' individual shapes and geometric properties as well as the "positional geometry" of the collection. The linking structure extends in a minimal way the individual "skeletal structures" on each of the regions, allowing us to significantly extend the mathematical methods introduced for single regions to the configuration. We prove for a generic configuration of regions the existence of a special type of Blum linking structure which builds upon the Blum medial axes of the individual regions. This requires proving several transversality theorems for certain associated "multi-distance" and "height-distance" functions for such configurations. We show that by relaxing the conditions on the Blum linking structures we obtain the more general class of skeletal linking structures which still capture the geometric properties. In addition to yielding geometric invariants which capture the shapes and geometry of individual regions, the linking structures are used to define invariants which measure positional properties of the configuration such as: measures of relative closeness of neighboring regions and relative significance of the individual regions for the configuration. These invariants, which are computed by formulas involving "skeletal linking integrals" on the internal skeletal structures, are then used to construct a "tiered linking graph," which identifies subconfigurations and provides a hierarchical ordering of the regions.Comment: 135 pages, 36 figures. Version to appear in Memoirs of the Amer. Math. So