2,065 research outputs found

    Climate, Wildfire, and Erosion Ensemble Foretells More Sediment in Western USA Watersheds

    Get PDF
    The area burned annually by wildfires is expected to increase worldwide due to climate change. Burned areas increase soil erosion rates within watersheds, which can increase sedimentation in downstream rivers and reservoirs. However, which watersheds will be impacted by future wildfires is largely unknown. Using an ensemble of climate, fire, and erosion models, we show that postfire sedimentation is projected to increase for nearly nine tenths of watersheds by \u3e10% and for more than one third of watersheds by \u3e100% by the 2041 to 2050 decade in the western USA. The projected increases are statistically significant for more than eight tenths of the watersheds. In the western USA, many human communities rely on water from rivers and reservoirs that originates in watersheds where sedimentation is projected to increase. Increased sedimentation could negatively impact water supply and quality for some communities, in addition to affecting stream channel stability and aquatic ecosystems

    Impact of Air Quality Regulations on Entrepreneurial Activity

    Get PDF
    The objective of this paper is to examine the impact of NAAQS non-attainment status on the entrepreneurial activity in a metropolitan statistical area (MSA). Most of the existing research on the relationship between non-attainment and the financial robustness of areas focuses on the big polluters (e.g., plastics, organic chemicals, steel smelting and refining, etc.), and examines how many of the big polluters failed or relocated, measured by the change in the number of plants/businesses when an area moved from attainment to non-attainment. Our paper will use a 306 MSA panel data set over the 1989-2003 timeframe, to address the question more comprehensively by looking at all industries, not just a targeted few polluters. Controlling for other time-variant confounding effects, such as population growth, per-capita income, tax rate changes, minimum wage rates, energy costs, regional inflation measures, and spatial phenomena (such as, natural disasters) we isolate the effect of non-attainment status on large polluters as well as the linkage industries. We show that if an area is designated non-attainment status in a particular year, it leads to a decline in the total number of business starts in the MSA in the following year. We also determine whether the impact of non-attainment varies across businesses of different sizes

    The Determinants of Credit Allocations in a Market-Based Trading System: Evidence from the RECLAIM Program

    Get PDF
    This paper examines the determinants of emission credit allocations under the Regional Clean Air Incentives Market (RECLAIM) - a program aimed at reducing nitrogen oxides (NOX) and sulfur oxides (SOX) - in the greater Los Angeles area. Our results suggest that deviations in the allocation of emission credits can be systematically explained by firm-level factors and the location of the facility. Our results also indicate that deviations in the allocation of emission credits may have been made in an attempt to regulate toxics, and that certain industries were protected in the early stages of the program

    Measuring the Effects of the Clean Air Act Amendments on Ambient PM\u3csub\u3e10\u3c/sub\u3e Concentrations: The Critical Importance of a Spatially Disaggregated Analysis

    Get PDF
    We examine the effects of the 1990 Clean Air Act Amendments (CAAAs) on ambient concentrations of PM10 in the United States between 1990 and 2005. We find that non-attainment designation has no effect on the \u27average monitor\u27 in non-attainment counties, after controlling for weather and socioeconomic characteristics at the county level. In sharp contrast, if we allow for heterogeneous treatment by type of monitor and county, we do find that the 1990 CAAAs produced substantial effects. Our best estimate suggests that PM10 concentrations at monitors with concentrations above the national annual standard dropped by between 7µg/m3 and 9µg/m3, which is roughly equivalent to a 11-14% drop. We also show that monitors which were in violation of the daily standard experience two fewer days in violation of the daily standard the following year. Empirical results suggest that this treatment effect is independent of whether the EPA has finalized the non-attainment designation

    Housing Market Effects of Inclusionary Zoning

    Get PDF
    This article presents an empirical analysis of the effects of inclusionary zoning policies on housing prices and starts in California during the period from 1988 through 2005. The analysis compares cities with and without such policies and isolates the effects of inclusionary zoning programs by carefully controlling for spatial and temporal conditions, such as the neighborhood or school district within which the house is located and changing market conditions over time. The analysis found that inclusionary zoning policies had measurable effects on housing markets in jurisdictions that adopt them; specifically, the price of single-family houses increases and the size of single-family houses decreases. The analysis also found that, although the cities with such programs did not experience a significant reduction in the rate of single-family housing starts, they did experience a marginally significant increase in multifamily housing starts. The magnitude of this shift varied with the stringency of the inclusionary requirements. Finally, the analysis found that the size of market-rate houses in cities that adopted inclusionary zoning increased more slowly than in cities without such programs. The results are fully consistent with economic theory and demonstrate that inclusionary zoning policies do not come without costs

    Climate Variability and Water Infrastructure: Historical Experience in the Western United States

    Get PDF
    Greater historical perspective is needed to enlighten current debate about future human responses to higher temperatures and increased precipitation variation. We analyze the impact of climatic conditions and variability on agricultural production in five semi-arid western states. We assemble county-level data on dams and other major water infrastructure; agricultural crop mixes and yields; precipitation and temperature; soil quality, and topography. Using this extensive data set, we analyze the impact of water infrastructure investments on crop mix and yields in affected counties relative to similarly-endowed counties that lack such infrastructure. We find that water infrastructure smoothes agricultural crop production and increases the likelihood of a successful harvest, especially during times of severe drought or excessive precipitation.

    Suppression of eukaryotic initiation factor 4E prevents chemotherapy-induced alopecia

    Get PDF
    BACKGROUND: Chemotherapy-induced hair loss (alopecia) (CIA) is one of the most feared side effects of chemotherapy among cancer patients. There is currently no pharmacological approach to minimize CIA, although one strategy that has been proposed involves protecting normal cells from chemotherapy by transiently inducing cell cycle arrest. Proof-of-concept for this approach, known as cyclotherapy, has been demonstrated in cell culture settings. METHODS: The eukaryotic initiation factor (eIF) 4E is a cap binding protein that stimulates ribosome recruitment to mRNA templates during the initiation phase of translation. Suppression of eIF4E is known to induce cell cycle arrest. Using a novel inducible and reversible transgenic mouse model that enables RNAi-mediated suppression of eIF4E in vivo, we assessed the consequences of temporal eIF4E suppression on CIA. RESULTS: Our results demonstrate that transient inhibition of eIF4E protects against cyclophosphamide-induced alopecia at the organismal level. At the cellular level, this protection is associated with an accumulation of cells in G1, reduced apoptotic indices, and was phenocopied using small molecule inhibitors targeting the process of translation initiation. CONCLUSIONS: Our data provide a rationale for exploring suppression of translation initiation as an approach to prevent or minimize cyclophosphamide-induced alopecia.1U01 CA168409 - NCI NIH HHS; P01 CA 87497 - NCI NIH HHS; P30 CA008748 - NCI NIH HHS; MOP-106530 - Canadian Institutes of Health Research; P01 CA013106 - NCI NIH HH

    The Ecological Niche of \u3ci\u3eEchinococcus multilocularis\u3c/i\u3e in North America: Understanding Biotic and Abiotic Determinants of Parasite Distribution with New Records in New Mexico and Maryland, United States

    Get PDF
    English abstract: Understanding the factors shaping the niche of parasites and its expression over geographical space and through time continues to be a modern scientific challenge with the results of research in this area directly influencing both theoretical and applied biology. This is especially important for proactive management of zoonotic parasites such as Echinococcus multilocularis, the etiologic agent of alveolar echinococcosis. Echinococcus multilocularis has a Holarctic distribution; with its geographic range and prevalence increasing recently in areas of the western Palearctic, while its distribution dynamics are poorly understood in the Nearctic. In this paper, we use an ecological niche modeling (ENM) approach to: i) estimate the current spatial distribution of suitable conditions for the parasite in the Nearctic. ii) Evaluate the abiotic and biotic factors influencing the species distribution. iii) Assess the potential impact of climatic change on the distribution of this species in the Nearctic. Additionally, we report two new occurrence records of this parasite that significantly expands its known geographic range. We reviewed the occurrence records of E. multilocularis for the Nearctic. This was complemented by two new records of the species from Maryland and New Mexico identified using morphology and multivariate morphometrics of the rostellar hooks. From these data we created two ENMs using the software Maxent. The first ENM included climatic variables, while the second included the same abiotic data plus biotic information consisting of four host community-related data sets. We evaluated model performance and variable importance to explore the relation of these variables to the parasite niche. Finally, we projected the resulting niche model onto future climate change scenarios. We found that an important portion of the Nearctic has suitable conditions for E. multilocularis with adequate habitat in the West and East of the continent where the parasite has not been detected. We also found that the proposed biotic variables improve the model performance and provide unique information, while the most critical abiotic variable was related to the amount of solar radiation. Finally, under the future emission scenarios explored, the distribution of suitable habitat for the parasite is predicted to increase by 56% to 76%. We obtained a robust model that provides detail on the distribution of suitable areas for E. multilocularis, including areas that have not been explored for the presence of the parasite. The host community variables included in this study seem a promising way to include biotic data for ecological parasite niche modeling. Resumen español: El estudio de los factores que moldean el nicho de los parásitos y como este se expresa en la distribución espacial y temporal de estos organismos es un reto de importancia para la biología aplicada y teórica. Esta información puede ser de especial importancia para parásitos zoonóticos tales como Echinococcus multilocularis, el cestodo causante de echinococcosis alveolar. Este parasito presenta una distribución Holártica, con un incremento reciente en rango geográfico y prevalencia documentados en Asia y Europa, mientras que en el Neártico, se desconoce la dinámica de distribución de la especie. En este estudio usamos modelos de nicho ecológico para: i) estimar la distribución actual de hábitat para la especie en Norteamérica. ii) Evaluar el efecto de factores bióticos y abióticos sobre la distribución de este parasito. iii) Evaluar el impacto potencial del cambio climático sobre su distribución. Adicionalmente, reportamos dos nuevos registros para la especie. En este trabajo revisamos los registros de ocurrencia de E. multilocularis en el Neártico. Esta información es complementada con dos nuevos registros provenientes de Maryland y Nuevo México identificados a partir de análisis morfológicos y morfométricos. Empleando el software Maxent, creamos dos modelos de nicho a partir de estos registros. El primer modelo se basó únicamente en variables abióticas, mientras que el segundo además de incluir las variables abióticas incluyó variables bióticas relacionadas con la comunidad de hospederos potenciales. Evaluamos el desempeño de cada modelo y la contribución de cada variable para explorar la relación de estas con el nicho del parásito. Finalmente, proyectamos los modelos al futuro bajo dos escenarios de emisiones de CO2. Encontramos que existen condiciones adecuadas para la especie en una porción importante del área de estudio, con áreas predichas al Este y Occidente del continente donde no se ha registrado el parásito. La inclusión de las variables bióticas resulta en modelos con mejor desempeño, así mismo, se evidencio que estas variables presentan información única no contenida en otras capas. La radiación solar fue la variable abiótica de mayor importancia. Finalmente, bajo los escenarios de cambio climático explorados, el área de hábitat adecuado para el parasito presenta un importante aumento de entre el 56% y 76%. En este trabajo obtuvimos un modelo robusto y detallado de la distribución de las condiciones ambientales adecuadas para E. multilocularis, el cual incluye zonas donde no ha sido reportada la presencia del parásito. Las variables relacionadas con la comunidad de hospederos incluidas en este trabajo parecen ser una manera prometedora de incluir información biótica en modelos de nicho de simbiontes

    Sources of surface O3 in the UK: tagging O3 within WRF-Chem

    Get PDF
    Tropospheric ozone (O3) concentrations depend on a combination of hemispheric, regional, and local-scale processes. Estimates of how much O3 is produced locally vs. transported from further afield are essential in air quality management and regulatory policies. Here, a tagged-ozone mechanism within the Weather Research and Forecasting model coupled with chemistry (WRF-Chem) is used to quantify the contributions to surface O3 in the UK from anthropogenic nitrogen oxide (NOx) emissions from inside and outside the UK during May–August 2015. The contribution of the different source regions to three regulatory O3 metrics is also examined. It is shown that model simulations predict the concentration and spatial distribution of surface O3 with a domain-wide mean bias of −3.7 ppbv. Anthropogenic NOx emissions from the UK and Europe account for 13 % and 16 %, respectively, of the monthly mean surface O3 in the UK, as the majority (71 %) of O3 originates from the hemispheric background. Hemispheric O3 contributes the most to concentrations in the north and the west of the UK with peaks in May, whereas European and UK contributions are most significant in the east, south-east, and London, i.e. the UK's most populated areas, intensifying towards June and July. Moreover, O3 from European sources is generally transported to the UK rather than produced in situ. It is demonstrated that more stringent emission controls over continental Europe, particularly in western Europe, would be necessary to improve the health-related metric MDA8 O3 above 50 and 60 ppbv. Emission controls over larger areas, such as the Northern Hemisphere, are instead required to lessen the impacts on ecosystems as quantified by the AOT40 metric
    corecore