194 research outputs found

    Environmental impact assessments of the Three Gorges Project in China: issues and interventions

    Get PDF
    The paper takes China's authoritative Environmental Impact Statement for the Yangzi (Yangtze) Three Gorges Project (TGP) in 1992 as a benchmark against which to evaluate emerging major environmental outcomes since the initial impoundment of the Three Gorges reservoir in 2003. The paper particularly examines five crucial environmental aspects and associated causal factors. The five domains include human resettlement and the carrying capacity of local environments (especially land), water quality, reservoir sedimentation and downstream riverbed erosion, soil erosion, and seismic activity and geological hazards. Lessons from the environmental impact assessments of the TGP are: (1) hydro project planning needs to take place at a broader scale, and a strategic environmental assessment at a broader scale is necessary in advance of individual environmental impact assessments; (2) national policy and planning adjustments need to react quickly to the impact changes of large projects; (3) long-term environmental monitoring systems and joint operations with other large projects in the upstream areas of a river basin should be established, and the cross-impacts of climate change on projects and possible impacts of projects on regional or local climate considered. © 2013 Elsevier B.V.Xibao Xu, Yan Tan, Guishan Yan

    Vegetation fire smoke, indigenous status and cardio-respiratory hospital admissions in Darwin, Australia, 1996–2005: a time-series study

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Air pollution in Darwin, Northern Australia, is dominated by smoke from seasonal fires in the surrounding savanna that burn during the dry season from April to November. Our aim was to study the association between particulate matter less than or equal to 10 microns diameter (PM<sub>10</sub>) and daily emergency hospital admissions for cardio-respiratory diseases for each fire season from 1996 to 2005. We also investigated whether the relationship differed in indigenous Australians; a disadvantaged population sub-group.</p> <p>Methods</p> <p>Daily PM<sub>10 </sub>exposure levels were estimated for the population of the city from visibility data using a previously validated model. We used over-dispersed Poisson generalized linear models with parametric smoothing functions for time and meteorology to examine the association between admissions and PM<sub>10 </sub>up to three days prior. An interaction between indigenous status and PM<sub>10 </sub>was included to examine differences in the impact on indigenous people.</p> <p>Results</p> <p>We found both positive and negative associations and our estimates had wide confidence intervals. There were generally positive associations between respiratory disease and PM<sub>10 </sub>but not with cardiovascular disease. An increase of 10 μg/m<sup>3 </sup>in same-day estimated ambient PM<sub>10 </sub>was associated with a 4.81% (95%CI: -1.04%, 11.01%) increase in total respiratory admissions. When the interaction between indigenous status and PM<sub>10 </sub>was assessed a statistically different association was found between PM<sub>10 </sub>and admissions three days later for respiratory infections of indigenous people (15.02%; 95%CI: 3.73%, 27.54%) than for non-indigenous people (0.67%; 95%CI: -7.55%, 9.61%). There were generally negative estimates for cardiovascular conditions. For non-indigenous admissions the estimated association with total cardiovascular admissions for same day ambient PM<sub>10 </sub>and admissions was -3.43% (95%CI: -9.00%, 2.49%) and the estimate for indigenous admissions was -3.78% (95%CI: -13.4%, 6.91%), although ambient PM<sub>10 </sub>did have positive (non-significant) associations with cardiovascular admissions of indigenous people two and three days later.</p> <p>Conclusion</p> <p>We observed positive associations between vegetation fire smoke and daily hospital admissions for respiratory diseases that were stronger in indigenous people. While this study was limited by the use of estimated rather than measured exposure data, the results are consistent with the currently small evidence base concerning this source of air pollution.</p

    Does the evidence about health risks associated with nitrate ingestion warrant an increase of the nitrate standard for drinking water?

    Get PDF
    Several authors have suggested that it is safe to raise the health standard for nitrate in drinking water, and save money on measures associated with nitrate pollution of drinking water resources. The major argument has been that the epidemiologic evidence for acute and chronic health effects related to drinking water nitrate at concentrations near the health standard is inconclusive. With respect to the chronic effects, the argument was motivated by the absence of evidence for adverse health effects related to ingestion of nitrate from dietary sources. An interdisciplinary discussion of these arguments led to three important observations. First, there have been only a few well-designed epidemiologic studies that evaluated ingestion of nitrate in drinking water and risk of specific cancers or adverse reproductive outcomes among potentially susceptible subgroups likely to have elevated endogenous nitrosation. Positive associations have been observed for some but not all health outcomes evaluated. Second, the epidemiologic studies of cancer do not support an association between ingestion of dietary nitrate (vegetables) and an increased risk of cancer, because intake of dietary nitrate is associated with intake of antioxidants and other beneficial phytochemicals. Third, 2–3 % of the population in Western Europe and the US could be exposed to nitrate levels in drinking water exceeding the WHO standard of 50 mg/l nitrate, particularly those living in rural areas. The health losses due to this exposure cannot be estimated. Therefore, we conclude that it is not possible to weigh the costs and benefits from changing the nitrate standard for drinking water and groundwater resources by considering the potential consequences for human health and by considering the potential savings due to reduced costs for nitrate removal and prevention of nitrate pollution

    Has Scots pine (Pinus sylvestris) co-evolved with Dothistroma septosporum in Scotland? Evidence for spatial heterogeneity in the susceptibility of native provenances

    Get PDF
    Spatial heterogeneity in pathogen pressure leads to genetic variation in, and evolution of, disease-related traits among host populations. In contrast, hosts are expected to be highly susceptible to exotic pathogens as there has been no evolution of defence responses. Host response to pathogens can therefore be an indicator of a novel or endemic pathosystem. Currently, the most significant threat to native British Scots pine (Pinus sylvestris) forests is Dothistroma needle blight (DNB) caused by the foliar pathogen Dothistroma septosporum which is presumed to be exotic. A progeny–provenance trial of 6-year-old Scots pine, comprising eight native provenances each with four families in six blocks, was translocated in April 2013 to a clear-fell site in Galloway adjacent to a DNB-infected forest. Susceptibility to D. septosporum, measured as DNB severity (estimated percentage nongreen current-year needles), was assessed visually over 2 years (2013–2014 and 2014–2015; two assessments per year). There were highly significant differences in susceptibility among provenances but not among families for each annual assessment. Provenance mean susceptibility to D. septosporum was negatively and significantly associated with water-related variables at site of origin, potentially due to the evolution of low susceptibility in the host in response to high historical pathogen pressure

    Environmental Geotechnics: Challenges and Opportunities in the Post COVID-19 World

    Get PDF
    The outbreak of the COVID-19 pandemic not only created a health crisis across the world but is expected to negatively impact the global economy and societies at a scale that maybe larger than the 2008 financial crisis. Simultaneously, it has inevitably exerted many negative consequences on the geoenvironment upon which human beings depend. The current article articulates the role of environmental geotechnics to elucidate and mitigate the effects of the current pandemic. It is the belief of all authors that the COVID-19 pandemic presents significant challenges, but also opportunities for the development of our field. Our discipline should make full use of our professional skills and expertise to look for development opportunities from this crisis, to highlight our discipline’s irreplaceable position in the global fight against pandemics, and to contribute to the health and prosperity of our communities, so as to better serve humankind. In order to reach this goal, while taking into account the specificity of the SARS-CoV-2 and the uncertainty of its environmental effects, it is believed that more emphasis should be placed on the following research directions: pathogen-soil interactions, isolation and remediation technologies for pathogen-contaminated sites, new materials for pathogen-contaminated soil, recycling and safe disposal of medical wastes, quantification of uncertainty in geoenvironmental and epidemiological problems, emerging technologies and adaptation strategies in civil, geotechnical, and geoenvironmental infrastructure, pandemic-induced environmental risk management, and model pathogen transport and fate in geoenvironment, among others. Moreover, COVID-19 has made it clear to the environmental geotechnics community the importance of urgent international cooperation and of multidisciplinary research actions that must extend to a broad range of scientific fields, including medical and public health disciplines, in order to meet the complexities posed by the COVID-19 pandemic

    Study of the doubly charmed tetraquark T+cc

    Get PDF
    Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the D0D0π+ mass spectrum just below the D*+D0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar T+cc tetraquark with a quark content of ccu⎯⎯⎯d⎯⎯⎯ and spin-parity quantum numbers JP = 1+. Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*+ mesons is consistent with the observed D0π+ mass distribution. To analyse the mass of the resonance and its coupling to the D*D system, a dedicated model is developed under the assumption of an isoscalar axial-vector T+cc state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the T+cc state. In addition, an unexpected dependence of the production rate on track multiplicity is observed
    corecore