17,913 research outputs found
(WP 2005-05) Assessing the Determinants of Willingness to Pay for Urban Flood Control: The Role of Locational, Demographic and Attitudinal Factors
The urbanization of urban watersheds can influence flooding risks. Traditional Federal Emergency Management Agency (FEMA) flood risk maps identify 100 year floodplains. These maps are updated infrequently. However, as a community urbanizes, flood risks can change, especially for downstream residents. Thus, one would expect that the willingness to pay (WTP) to prevent the worsening of flooding risk would depend in part on the location of the household in the community and their associated flooding risk. Economists and regional scientists have evaluated the role played by traditional demographic factors. However, attitudinal factors measuring community norms, political philosophy, and other psychological factors that may be unique to the individual have not received the same level of scrutiny.
Milwaukee, WI has experienced major flooding events, classified as floods with an expected frequency of once every 100 years or less, in 1986 and most recently in 1997 and 1998. In this study, 1000 residents of the Menomonee watershed in Milwaukee were interviewed in a two-wave panel survey (i.e., telephone interviews took place in 2000 and 2001) to determine their willingness to pay for a referendum which would prevent flood risks from worsening. The interviews queried respondents about their attitudes concerning flooding and ecological risks, political beliefs, information seeking behavior, and other psychological factors unique to the respondent. Information was also gathered on demographic characteristics of the respondent, and also that individuals address. The address was geocoded and hydrologic modeling was used to determine the unique flood risk associated with the residence. A willingness to pay function was estimated using Tobit analysis. Preliminary findings indicated that all three categories of factors influence willingness to pay, with psychological factors and flood risk factors having a relatively strong impact on willingness to pay
Urban Watershed/Water Body Restoration - The Driving Forces
Urban streams are used for several purposes. Some uses are conflicting and some are complementary. The use of urban water bodies and the resolution of conflicts is driven by anthropogenic and biocentric/ecocentric interests that must be optimized and the conflicts resolved. This article examines and analyzes land ethics (biocentric) and socio-economic (anthropocentric) drives for stream restoration of urban watersheds located in the Milwaukee (WI) metropolitan area. The basins experienced increased flooding, significant degradation of sediment and water quality, and loss of aquatic species, all due to urbanization. It was found that the primary drivers for restoration of urban streams are the ethical attitudes of population towards the ecocentric benefits of restoration in combination with a desire for flood control. A Contingent Valuation Survey of citizens residing in two Milwaukee watersheds revealed that those who see the watershed in ecocentric terms appear to have a greater Willingness to Pay for watershed/water body improvements than those who see the benefits solely in anthropogenic terms of reduction of flood damages
On Bayesian nonparametric modelling of two correlated distributions
In this paper, we consider the problem of modelling a pair of related distributions
using Bayesian nonparametric methods. A representation of the distributions as
weighted sums of distributions is derived through normalisation. This allows us to
define several classes of nonparametric priors. The properties of these distributions
are explored and efficient Markov chain Monte Carlo methods are developed. The
methodology is illustrated on simulated data and an example concerning hospital efficiency
measurement
Adaptive MC^3 and Gibbs algorithms for Bayesian Model Averaging in Linear Regression Models
The MC (Madigan and York, 1995) and Gibbs (George and McCulloch, 1997)
samplers are the most widely implemented algorithms for Bayesian Model
Averaging (BMA) in linear regression models. These samplers draw a variable at
random in each iteration using uniform selection probabilities and then propose
to update that variable. This may be computationally inefficient if the number
of variables is large and many variables are redundant. In this work, we
introduce adaptive versions of these samplers that retain their simplicity in
implementation and reduce the selection probabilities of the many redundant
variables. The improvements in efficiency for the adaptive samplers are
illustrated in real and simulated datasets
The effects of label design characteristics on perceptions of genetically modified food
Objective. To explore the effects on perceptions of labelling food for genetically modified content. Background: there is increasing public pressure for the compulsory labelling of genetically modified food content on all food products, and yet little is known about how the design and content of such food labels will influence product perceptions. The current research draws upon warning label research - a field in which the effect of label design manipulations on perceptions of, and responses to, potential or perceived risks is well documented. Method. Two experiments are reported that investigate how label design features influence the perception of genetically modified foods. The effects of label colour (red, blue and green), wording style (definitive vs. probabilistic and explicit vs. non-explicit) and information source (government agency, consumer group and manufacturer) on hazard perceptions and purchase intentions were measured. Results. Hazard perceptions and purchase intentions were both influenced by label design characteristics in predictable ways. Any reference to genetic modification, even if the label is stating that the product is free of genetically modified ingredients, increased hazard perception, and decreased purchase intentions, relative to a no-label condition. Conclusion. Label design effects generalise from warning label research to influence the perception of genetically modified foods in predictable ways. Application. The design of genetically modified food labels. Ā© 2012 Copyright Taylor and Francis Group, LLC
Simultaneous measurements of particulate and gas-phase water-soluble organic carbon concentrations at remote and urban-influenced locations
The sources, sinks, and overall importance of watersoluble organic carbon (WSOC) in the atmosphere are not well understood. Although the primary historical focus has been on particulate WSOC (WSOCP), here we also present results obtained using a newly developed technique that additionally measures gas-phase water-soluble organic carbon (WSOCG). These first-of-their-kind measurements show that WSOCG can often be more than ten times larger than WSOCP at both urban and remote locations. The average fraction of WSOC residing in the gas phase (fg = WSOCG/(WSOCG + WSOCP)) at five various field sites ranged from 0.64 to 0.93, implying significant differences in WSOC phase partitioning between locations. At Houston, TX, and Summit, Greenland, a repeatable diurnal pattern was observed, with minimum values for fg occurring at night. These trends likely are due, at least in part, to temperature and/or relative humidity related gas-to-particle partitioning. These coincident measurements of WSOC in both the gas and particle phases indicate that a relatively large reservoir of water-soluble organic mass is not taken into account by measurements focused only on WSOCP. In addition, a significant amount of WSOCG is available to form WSOCP or enter cloud droplets depending on the chemical and physical properties of the droplets and/or aerosols present. Citation: Anderson, C., J. E. Dibb, R. J. Griffin, and M. H. Bergin (2008), Simultaneous measurements of particulate and gas-phase water-soluble organic carbon concentrations at remote and urban-influenced locations, Geophys. Res. Lett., 35, L13706, doi:10.1029/2008GL033966
S-band antenna phased array communications system
The development of an S-band antenna phased array for spacecraft to spacecraft communication is discussed. The system requirements, antenna array subsystem design, and hardware implementation are examined. It is stated that the phased array approach offers the greatest simplicity and lowest cost. The objectives of the development contract are defined as: (1) design of a medium gain active phased array S-band communications antenna, (2) development and test of a model of a seven element planar array of radiating elements mounted in the appropriate cavity matrix, and (3) development and test of a breadboard transmit/receive microelectronics module
- ā¦