1,881 research outputs found

    Monetary benefits of preventing childhood lead poisoning with lead-safe window replacement

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    Previous estimates of childhood lead poisoning prevention benefits have quantified the present value of some health benefits, but not the costs of lead paint hazard control or the benefits associated with housing and energy markets. Because older housing with lead paint constitutes the main exposure source today in the U.S., we quantify health benefits, costs, market value benefits, energy savings, and net economic benefits of lead-safe window replacement (which includes paint stabilization and other measures). The benefit per resident child from improved lifetime earnings alone is 21,195inpre1940housingand21,195 in pre-1940 housing and 8,685 in 1940-59 housing (in 2005 dollars). Annual energy savings are 130to130 to 486 per housing unit, with or without young resident children, with an associated increase in housing market value of 5,900to5,900 to 14,300 per housing unit, depending on home size and number of windows replaced. Net benefits are 4,490to4,490 to 5,629 for each housing unit built before 1940, and 491to491 to 1,629 for each unit built from 1940-1959, depending on home size and number of windows replaced. Lead-safe window replacement in all pre-1960 U.S. housing would yield net benefits of at least $67 billion, which does not include many other benefits. These other benefits, which are shown in this paper, include avoided Attention Deficit Hyperactivity Disorder, other medical costs of childhood lead exposure, avoided special education, and reduced crime and juvenile delinquency in later life. In addition, such a window replacement effort would reduce peak demand for electricity, carbon emissions from power plants, and associated long-term costs of climate change.Lead Poisoning, IQ, Energy Efficiency, Cost Benefit Analysis, Housing, Climate Change

    Safety at what price? : setting anti-terrorist policies for checked luggage on US domestic aircraft

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    Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management, Operations Research Center, 2000.Includes bibliographical references (leaves 45-46).In this thesis, we considered the costs and benefits of implementing Positive Passenger Bag Match (PPBM) - an anti-terrorist measure to keep bombs out of checked luggage - on US domestic passenger flights. We constructed a stochastic model for comparing the cost-effectiveness of three alternative approaches to PPBM: no PPBML implementation; a PPBM implementation that is applied to 5% of passengers; and a full (100%) implementation of PPBM. We made ranges of estimates concerning the level of terrorist risk, the costs of PPBM operation, the consequences of successful terrorist bombings, and the anti-terrorist effectiveness of both the partial and full PPBM implementations. Calculations showed that there were circumstances under which each policy was the most cost-effective of the three. Of the three options, not implementing PPBM at all was the most cost-effective approach for the largest percentage of the scenarios considered. We found that 5% PPBM captured the next largest portion of the scenarios, and was generally the optimal strategy when annual PPBMI operation costs were low, when 5% PPBM anti-terrorist effectiveness was high, and when the consequences of successful bombings were severe. We found 100%(. PPBM to be the optimal strategy for most scenarios which involved highly costly terrorist bombings, a high level of terrorist risk, and a 100% PPBM policy that provided much added security over 5% PPBM.by Jonathan E.W. Cohen.S.M

    Reduced Sensitivity to Immediate Reward during Decision-Making in Older than Younger Adults

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    We examined whether older adults differ from younger adults in the degree to which they favor immediate over delayed rewards during decision-making. To examine the neural correlates of age-related differences in delay discounting we acquired functional MR images while participants made decisions between smaller but sooner and larger but later monetary rewards. The behavioral results show age-related reductions in delay discounting. Less impulsive decision-making in older adults was associated with lower ventral striatal activations to immediate reward. Furthermore, older adults showed an overall higher percentage of delayed choices and reduced activity in the dorsal striatum than younger adults. This points to a reduced reward sensitivity of the dorsal striatum in older adults. Taken together, our findings indicate that less impulsive decision-making in older adults is due to a reduced sensitivity of striatal areas to reward. These age-related changes in reward sensitivity may result from transformations in dopaminergic neuromodulation with age

    Bolometric luminosities and infrared properties of carbon stars in the Magellanic Clouds and the Galaxy

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    Broad band J, H, K photometry and narrow band CO and H_2O indices have been obtained for 89 luminous red stars in the Large Magellanic Cloud (LMC) and 21 in the Small Magellanic Cloud (SMC), chosen largely from the sample of Blanco, McCarthy, and Blanco. Most are known to be carbon stars, and their infrared properties are compared with new observations of 33 galactic carbon stars. The bolometric luminosity distributions of an unbiased sample of Magellanic Cloud carbon stars are compared with those predicted from evolutionary calculations by Renzini and Voli for double shell burning stars undergoing He shell flashes. The observed and theoretical distributions disagree markedly: nearly all the observed stars have lower luminosities than even the faintest theoretical carbon star. In addition, we find many fewer than expected high luminosity stars with initial mass greater than 3 M_⊙. Possible explanations for this include a steep initial mass function for intermediate mass stars, a star formation rate significantly higher in the past than at present, or a neglected physical effect, such as underestimation of the importance of mass loss. Nevertheless, it appears that the hypothesis that He shell flashes lead to a dredge-up of carbon into the envelope, which results in a carbon star, can be maintained, if dredging occurs after fewer shell flashes than are predicted by presently available stellar evolutionary calculations. The colors and indices of the late M giants in the LMC field are similar to those of late M giants in the Galaxy. The narrow band infrared data are interpreted qualitatively in terms of the effects of molecular band absorption, which also strongly influences the infrared broad band colors of carbon stars. The small differences in the color-color relationships of the SMC and LMC samples are consistent with the differences in heavy metal abundance between the LMC, SMC, and Galaxy

    Environmental Correlates of Breeding in the Crested Caracara (Caracara cheriway)

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    We evaluated the influence of weather on reproduction of the Crested Caracara (Caracara cheriway) in an agricultural landscape in south-central Florida. We used a mixed logistic-regression modeling approach within an information-theoretic framework to examine the influence of total rainfall, rainfall frequency, and temperature on the number of breeding pairs, timing of breeding, nest success, and productivity of Crested Caracaras during 1994–2000. The best models indicated an influence of rainfall frequency and laying period on reproduction. More individuals nested and more pairs nested earlier during years with more frequent rainfall in late summer and early fall. Pairs that nested later in each breeding season had smaller clutches, lower nest success and productivity, and higher probability of nest failure. More frequent rainfall during early spring months that are usually characterized by water deficit (March–May), more frequent rainfall during the fall drawdown period (September–November), and a shorter winter dry period showed some association with higher probability of brood reduction and lower nest success. The proportion of nests that failed was higher in wet years, when total rainfall during the breeding season (September–April) was \u3e10% above the 20-year average. Rainfall may influence reproduction in Crested Caracaras indirectly through food resources. As total rainfall increased during February–April, when most pairs are feeding nestlings or dependent fledglings, the proportion of drawdown-dependent species (those that become available as rainfall decreases and wetlands become isolated and shallow) in the diet of Crested Caracaras declined, which may indicate reduced availability of foraging habitat for this primarily terrestrial raptor

    Effect of Iodine on Mercury Concentrations in Dental-unit Wastewater

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    Dental amalgam is a mixture of mercury, silver, tin, and copper. Mercury typically makes up about 50% of it. The amalgam is used to provide the dental patient with a strong durable filling. Some of the dental amalgam may end up in the dental wastewater along with the water used for rinsing. Iodine is often used to control bacteria in dental-unit fresh waterlines. Could Iodine effect mercury concentrations in the wastewater?ISTC partnered with researchers at the Naval Institute for Dental and Biomedical Research to answer that question. Full results appear in Stone, Mark E., et al (2006). "Effect of Iodine on Mercury Concentrations in Dental-unit Wastewater." Dental Materials 22(2), 119-124. https://doi.org/10.1016/j.dental.2005.04.009.Ope
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