710 research outputs found

    Crash Risk Reduction at Signalized Intersections Using Longitudinal Data

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    This study extends the previous work of Burkey and Obeng (2004) that examined the impact of red light cameras on the type and severity of crashes at signalized intersections in Greensboro, NC. The extension takes the following form. First, we extend the data to cover 57 months, and to include demographics, technology variables, the condition of a driver at the time of the crash, vehicle characteristics, land use and visual obstruction. Second, instead of examining the impact of red light cameras, we focus on identifying the determinants of crash severity, two-vehicle crashes, and property damage costs. The major findings are that the safety impacts of seatbelt use outweigh the impacts of airbags deploying because the latter tends to increase evident injuries and property damage costs, while the former reduces these injuries. We also find that head-on collisions and under rides increase evident injuries. For two-vehicle crashes, we find that the risk of severe injuries increases in pickup-pickup crashes and SUV-pickup crashes, while the risk of possible injuries increases in car-truck crashes. For property damage costs, we found the condition of the driver at the time of the crash (i.e., illness, impaired, medical condition, driver falling asleep, driver apparently normal) to be important determinants in increasing these costs. The types of accidents that we found to increase property damage costs are running into a fixed object and under rides. Finally, we found that property damage costs of crashes are low where the land uses are commercial and institutional suggesting that the accidents that occur in these areas are minor.longitudinal data; accidents; intersections

    Historical and simulated ecosystem carbon dynamics in Ghana: land use, management, and climate

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    International audienceWe used the General Ensemble biogeochemical Modeling System (GEMS) to simulate responses of natural and managed ecosystems to changes in land use, management, and climate for a forest/savanna transitional zone in central Ghana. Model results show that deforestation for crop production during the last century resulted in a substantial reduction in ecosystem carbon (C) stock from 135.4 Mg C ha?1 in 1900 to 77.0 Mg C ha?1 in 2000, and in soil organic C stock within the top 20 cm of soil from 26.6 Mg C ha?1 to 21.2 Mg C ha?1. If no land use change takes place from 2000 through 2100, low and high climate change scenarios (increase in temperature and decrease in precipitation over time) will result in losses of soil organic C stock by 19% and 25%, respectively. A low nitrogen (N) fertilization rate is the principal constraint on current crop production. An increase in N fertilization under the low climate change scenario would increase crop yield by 14% with 30 kg N ha?1 and by 38% with 60 kg N ha?1, leading to an increase in the average soil C stock by 12% and 29%, respectively, in all cropland by 2100. The results suggest that the climate changes in the future from current climate conditions will not necessarily become a determinant control on ecosystem C fluxes and crop production, while a reasonable N fertilization rate is critical to achieve food security and agricultural sustainability in the study area through the 21st century, and current cropping systems could be optimized to make full use of the rainfall resource

    A Case of Urogenital Human Schistosomiasis from a Non-endemic Area

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    © 2015 Calvo-Cano et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article

    Isothermal Recombinase Polymerase amplification (RPA) of Schistosoma haematobium DNA and oligochromatographic lateral flow detection

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    © 2015 Rosser et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. The attached file is the published version of the article

    Influence of operating parameters on the biodegradation of steroid estrogens and nonylphenolic compounds during biological wastewater treatment processes

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    This document is the unedited author's version of a Submitted Work that was subsequently accepted for publication in Environmental Science & Technology, copyright © American Chemical Society after peer review. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/es901612v.This study investigated operational factors influencing the removal of steroid estrogens and nonylphenolic compounds in two sewage treatment works, one a nitrifying/denitrifying activated sludge plant and the other a nitrifying/denitrifying activated sludge plant with phosphorus removal. Removal efficiencies of >90% for steroid estrogens and for longer chain nonylphenol ethoxylates (NP4−12EO) were observed at both works, which had equal sludge ages of 13 days. However, the biological activity in terms of milligrams of estrogen removed per day per tonne of biomass was found to be 50−60% more efficient in the nitrifying/denitrifying activated sludge works compared to the works which additionally incorporated phosphorus removal. A temperature reduction of 6 °C had no impact on the removal of free estrogens, but removal of the conjugated estrone-3-sulfate was reduced by 20%. The apparent biomass sorption (LogKp) values were greater in the nitrifying/denitrifying works than those in the nitrifying/denitrifying works with phosphorus removal for both steroid estrogens and nonylphenolic compounds possibly indicating a different cell surface structure and therefore microbial population. The difference in biological activity (mg tonne−1 d−1) identified in this study, of up to seven times, suggests that there is the potential for enhancing the removal of estrogens and nonylphenols if more detailed knowledge of the factors responsible for these differences can be identified and maximized, thus potentially improving the quality of receiving waters.Public Utilities Board (Singapore), Anglian Water Ltd, Severn Trent Water Ltd, Thames Water Utilities Ltd, United Utilities 393 Plc and Yorkshire Water Services

    Crash Risk Reduction at Signalized Intersections Using Longitudinal Data

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    This study extends the previous work of Burkey and Obeng (2004) that examined the impact of red light cameras on the type and severity of crashes at signalized intersections in Greensboro, NC. The extension takes the following form. First, we extend the data to cover 57 months, and to include demographics, technology variables, the condition of a driver at the time of the crash, vehicle characteristics, land use and visual obstruction. Second, instead of examining the impact of red light cameras, we focus on identifying the determinants of crash severity, two-vehicle crashes, and property damage costs. The major findings are that the safety impacts of seatbelt use outweigh the impacts of airbags deploying because the latter tends to increase evident injuries and property damage costs, while the former reduces these injuries. We also find that head-on collisions and under rides increase evident injuries. For two-vehicle crashes, we find that the risk of severe injuries increases in pickup-pickup crashes and SUV-pickup crashes, while the risk of possible injuries increases in car-truck crashes. For property damage costs, we found the condition of the driver at the time of the crash (i.e., illness, impaired, medical condition, driver falling asleep, driver apparently normal) to be important determinants in increasing these costs. The types of accidents that we found to increase property damage costs are running into a fixed object and under rides. Finally, we found that property damage costs of crashes are low where the land uses are commercial and institutional suggesting that the accidents that occur in these areas are minor

    Commonwealth Professional Fellowship: the wealth of experience and lessons learned.

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    The Commonwealth Professional Fellowship (CPF) is a programme of the Commonwealth Scholarship Commission in association with the British Council. The Fellowship is aimed at providing a professional development opportunity for mid-career professionals from Commonwealth developing countries in diverse disciplines. Fellows who take part in this programme spend a period of one to three months in the United Kingdom to keep abreast of current trends and developments, and receive training in appropriate fields

    Uncoupling of neurogenesis and differentiation during retinal development

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    Conventionally, neuronal development is regarded to follow a stereotypic sequence of neurogenesis, migration, and differentiation. We demonstrate that this notion is not a general principle of neuronal development by documenting the timing of mitosis in relation to multiple differentiation events for bipolar cells (BCs) in the zebrafish retina using in vivo imaging. We found that BC progenitors undergo terminal neurogenic divisions while in markedly disparate stages of neuronal differentiation. Remarkably, the differentiation state of individual BC progenitors at mitosis is not arbitrary but matches the differentiation state of post-mitotic BCs in their surround. By experimentally shifting the relative timing of progenitor division and differentiation, we provide evidence that neurogenesis and differentiation can occur independently of each other. We propose that the uncoupling of neurogenesis and differentiation could provide neurogenic programs with flexibility, while allowing for synchronous neuronal development within a continuously expanding cell pool

    IFNAR1-Signalling Obstructs ICOS-mediated Humoral Immunity during Non-lethal Blood-Stage Plasmodium Infection

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    Funding: This work was funded by a Career Development Fellowship (1028634) and a project grant (GRNT1028641) awarded to AHa by the Australian National Health & Medical Research Council (NHMRC). IS was supported by The University of Queensland Centennial and IPRS Scholarships. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Microbial and antibiotic contaminants in imported and locally produced honey in the tamale metropolis of the Northern Region of Ghana

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    Honey remains a valued natural product and has been used by humans as an important food source, disease treatment, and a healthy sugar source since ancient times. However, recent reports on the adulteration of honey and honey polluted with contaminants like pesticides, heavy metals, microorganisms as well as antibiotics have gained public attention. Thus, this study aimed to assess the quality and safety of imported and locally produced honey by specifically determining microbial and antibiotic contaminants as well as the beekeeping practices of honey producers within some locations of the Tamale metropolis. A semi-structured questionnaire was designed to gather information on the sources of honey, knowledge of diseases affecting bees, knowledge of contamination of honey, and knowledge of antibiotics use in honey production from honey producers in the study area. The procedures outlined by the Codex Alimentarius Commission were followed to ascertain the microbial quality of the honey samples. Also, the Premi® test kit was used to determine the presence of antibiotics residue in the honey samples. Only eight honey producers were identified in the study area; they all had knowledge on contamination of honey. Only two (25 %) of the honey producers had knowledge on diseases affecting bees and also the use of antibiotics in beekeeping or honey production. Concerning microbial contaminants, Listeria spp., Lactobacillus spp., Salmonella spp., Escherichia coli, Clostridium spp., Campylobacter spp., and Staphylococcus spp. were the microorganisms enumerated upon microbiological quality assessment of 30 honey samples. Furthermore, 27 (90 %) of the honey samples tested positive for the presence of antibiotics residue of which 6 (85.7 %) were sampled from imported source, whilst the remaining 21 (91.3 %) were locally produced. Microbial and antibiotic contaminants found in the honey sampled in the study area support the hypothesis that honey may not be as pure as might be perceived and this might be a public health concern. Again, since there is no available record on the  screening or antibiotic residue in honey found on the Ghanaian market, this research is timely and necessary to provide the basis forintervention policies on the minimum limits of antibiotic residues present in honey. Key words: Antibiotic, Campylobacter, Clostridium, Contaminants, Honey, Listeria, Microorganism, Residues, Tamale Metropoli
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