Health and the Urban Transition Effects of Household Perceptions, Illness, and Environmental Pollution on Clean Water Investment

Recent efforts to reinvigorate the connections between urban planning and health have usefully brought the field back to one of its original roles. Current research, however, has focused on industrialized cities, overlooking some of the important urbanization processes in poor countries. This paper describes an emerging ‘health transition’ and the importance of socio-ecological approaches to understanding new health challenges in the developing world and uses the empirical case of Vietnam to examine the development dilemma of new industrial health concerns associated with economic development. The paper summarizes original qualitative data suggesting that one of the main benefits and rationales of the system is the improvement in public health that it has promoted. Using a related original sample survey (n=200) from 2005, the paper then tests a set of hypotheses about the relationship between illness, connections to the new system, and the role of pollution of natural water sources in illness. Findings suggest that fears of illness, and in particular new forms of industrial illnesses, are growing with rapid development as old forms of acute water borne disease are of less concern.Water supply, perceptions, environmental health, transition, urbanization

The sign problem in full configuration interaction quantum Monte Carlo: Linear and sub-linear representation regimes for the exact wave function

We investigate the sign problem for full configuration interaction quantum Monte Carlo (FCIQMC), a stochastic algorithm for finding the ground state solution of the Schr\"odinger equation with substantially reduced computational cost compared with exact diagonalisation. We find $k$-space Hubbard models for which the solution is yielded with storage that grows sub-linearly in the size of the many-body Hilbert space, in spite of using a wave function that is simply linear combination of states. The FCIQMC algorithm is able to find this sub-linear scaling regime without bias and with only a choice of Hamiltonian basis. By means of a demonstration we solve for the energy of a 70-site half-filled system (with a space of $10^{38}$ determinants) in 250 core hours, substantially quicker than the $\sim$10$^{36}$ core hours that would be required by exact diagonalisation. This is the largest space that has been sampled in an unbiased fashion. The challenge for the recently-developed FCIQMC method is made clear: expand the sub-linear scaling regime whilst retaining exact on average accuracy. This result rationalizes the success of the initiator adaptation (i-FCIQMC) and offers clues to improve it. We argue that our results changes the landscape for development of FCIQMC and related methods.Comment: 6 pages, 4 figures. The mentioned supplementary material is included as "Ancillary files". Comments welcom

What Are Ecosystem Services?

This paper advocates consistently defined units of account to measure the contributions of nature to human welfare. We argue that such units have to date not been defined by environmental accounting advocates and that the term “ecosystem services” is too ad hoc to be of practical use in welfare accounting. We propose a definition, rooted in economic principles, of ecosystem service units. A goal of these units is comparability with the definition of conventional goods and services found in GDP and the other national accounts. We illustrate our definition of ecological units of account with concrete examples. We also argue that these same units of account provide an architecture for environmental performance measurement by governments, conservancies, and environmental markets.Environmental accounting, ecosystem services, index theory, nonmarket valuation

Designing economic instruments for the environment in a decentralized fiscal system

When external effects are important, markets will be inefficient, and economists have considered several broad classes of economic instruments to correct these inefficiencies. However, the standard economic analysis has tended to neglect important distinctions and interactions between the geographic scope of pollutants, the enforcement authority of various levels of government, and the fiscal responsibilities of the levels of government. For example, externalities generated in a particular local area may be confined to the local area or may spill over to other jurisdictions. Also, local governments may be well informed about how best to regulate or enforce pollution control within their jurisdiction, but they may not consider the effects of their actions on other jurisdictions. Finally, the existence of locally-generated waste emissions affects the appropriate assignment of both expenditure and tax responsibilities among levels of government. The standard analysis therefore focuses mainly upon an aggregate (or national) perspective, it typically ignores the possibility that the externality may be created and addressed by local governments, and it does not consider the implications of decentralization for the design of economic instruments targeted at environmental problems. This paper examines the implications of decentralization for the design of corrective policies; that is, how does one design economic instruments in a decentralized fiscal system in which externalities exist at the local level and in which subnational governments have the power to provide local public services, as well as to choose tax instruments that can both finance these expenditures and correct the market failures of externalities?Environmental Economics&Policies,Debt Markets,Taxation&Subsidies,Public Sector Economics&Finance,Emerging Markets

Designing Economic Instruments for the Environment in a Decentralized Fiscal System

When external effects are important, markets will be inefficient, and economists have considered several broad classes of economic instruments to correct these inefficiencies. However, the standard economic analysis has tended to take the region, and the government, as a given; that is, this work has neglected important distinctions and interactions between the geographic scope of different pollutants, the enforcement authority of various levels of government, and the fiscal responsibilities of the various levels of government. It typically ignores the possibility that the externality may be created and addressed by local governments, and it does not consider the implications of decentralization for the design of economic instruments targeted at environmental problems. This paper examines the implications of decentralization for the design of corrective policies; that is, how does one design economic instruments in a decentralized fiscal system in which externalities exist at the local level and in which subnational governments have the power to provide local public services and to choose tax instruments that can both finance these expenditures and correct the market failures of externalities?market failure, environmental federalism, externalities, fiscal decentralization, subsidiarity principle, economic instruments

The Architecture and Measurement of an Ecosystem Services Index

This paper describes the construction of an ecological services index (ESI). An ESI is meant to summarize and track over time the magnitude of beneficial services arising from the natural environment. A central task of this paper is to define rigorously ecosystem services so that services can be counted in an economically and ecologically defensible manner—a requirement if ecological contributions to welfare are to be incorporated into the national accounts. This paper advocates a particular economic structure and relates it to index theory and makes concrete recommendations for the measurement of such an index.ecosystem services, Green GDP, index numbers, ecological economics

Many-- body problems

Imperial Users onl

Chemiluminescent Tags for Tracking Insect Movement in Darkness: Application to Moth Photo-Orientation

The flight tracks of Manduca sexta (Lepidoptera: Sphingidae) flying toward a 5 watt incandescent light bulb were recorded under low light conditions with the aid of a camera-mounted photomultiplier and a glowing marker technique. Small felt pads bearing a chemiluminescent (glowi ma­erial, Cyalume®, were affixed to the abdomens of free-flying moths. insects orienting to a dim incandescent bulb were easily visible to the naked eye and were clearly captured on videotape. On their initial approach to the light source, M. sexta were found to orient at a mean angle of -0.220 ± 2.70 (mean ± SEM). The speed of the initial approach flight (OA ± 0.03 m/s) was significantly faster than the speed immediately after passing the light (0.29 ± 0.02 m/s; t =6.4, PM. sexta initially fly approximately at a light source and only after passing it, do they engage in circular flight around the source. M. sexta flight to lights does not entirely match any paths predicted by several light orientation mechanisms, including the commonly invoked light compass theory