254 research outputs found

    Thermal Investigation of Stormwater Management Ponds

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    Abstract Stormwater management wet ponds increase runoff temperatures in discharge waters during summer months. These increases in temperatures adversely affect receiving urban stream ecosystems. Monitoring results for three summers (2009 to 2011) from four stormwater management ponds in the cities of Guelph and Kitchener, Ontario are employed to advance our knowledge of key design parameters that influence the thermal enrichment of stormwater discharges. An artificial neural network model was developed to predict the event mean temperature at the pond outlet. The artificial neural network model explains 99% of the variability in outlet event temperature. Sensitivity analyses show that increasing the permanent pond volume from 2 000 m³ to 4 000 m³ results in an average increase of 5 °C in outlet event mean temperature. Similarly, increasing the travel path ratio from 0.6 m to 1.2 m confirmed an average increase of 6 °C in outlet event mean temperature. In addition, ponds with average depths >1.0 m can result in significant decreases in pond outlet water temperature when using bottom draw structures. The results can lead to the promotion of the design of deeper ponds with bottom draw outlets and smaller travel path ratios. However, the implications of this approach on other performance criteria should be evaluated

    The Effects of Cocaine on Different Redox Forms of Cysteine and Homocysteine, and on Labile, Reduced Sulfur in the Rat Plasma Following Active versus Passive Drug Injections

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    Received: 28 November 2012 / Revised: 19 April 2013 / Accepted: 6 May 2013 / Published online: 16 May 2013 The Author(s) 2013. This article is published with open access at Springerlink.comThe aim of the present studies was to evaluate cocaine-induced changes in the concentrations of different redox forms of cysteine (Cys) and homocysteine (Hcy), and products of anaerobic Cys metabolism, i.e., labile, reduced sulfur (LS) in the rat plasma. The above-mentioned parameters were determined after i.p. acute and subchronic cocaine treatment as well as following i.v. cocaine self-administration using the yoked procedure. Additionally, Cys, Hcy, and LS levels were measured during the 10-day extinction training in rats that underwent i.v. cocaine administration. Acute i.p. cocaine treatment increased the total and protein-bound Hcy contents, decreased LS, and did not change the concentrations of Cys fractions in the rat plasma. In turn, subchronic i.p. cocaine administration significantly increased free Hcy and lowered the total and protein-bound Cys concentrations while LS level was unchanged. Cocaine self-administration enhanced the total and protein-bound Hcy levels, decreased LS content, and did not affect the Cys fractions. On the other hand, yoked cocaine infusions did not alter the concentration of Hcy fractions while decreased the total and protein-bound Cys and LS content. This extinction training resulted in the lack of changes in the examined parameters in rats with a history of cocaine self-administration while in the yoked cocaine group an increase in the plasma free Cys fraction and LS was seen. Our results demonstrate for the first time that cocaine does evoke significant changes in homeostasis of thiol amino acids Cys and Hcy, and in some products of anaerobic Cys metabolism, which are dependent on the way of cocaine administration

    Perinatal Hypoxia-Ischemia Disrupts Striatal High-Affinity [ 3 H]Glutamate Uptake into Synaptosomes

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    : We examined the impact of hypoxia-ischemia on high-affinity [ 3 H]glutamate uptake into a synaptosomal fraction prepared from immature rat corpus striatum. In 7-day-old pups the right carotid artery was ligated, and pups were exposed to 8% oxygen for 0, 0.5, 1, or 2.5 h, and allowed to recover for up to 24 h before they were killed. High-affinity glutamate uptakes in striatal synaptosomes derived from tissue ipsilateral and contralateral to ligation were compared. After 1 h of hypoxia plus ischemia, high-affinity glutamate uptake in the striatum was reduced by 54 ± 13% compared with values from the opposite (nonischemic) side of the brain (p < 0.01, t test versus ligates not exposed to hypoxia). There were similar declines after 2.5 h of hypoxiaischemia. Activity remained low after a 1 h recovery period in room air, but after 24 h of recovery, high-affinity glutamate uptake was equal bilaterally. Kinetic analysis revealed that loss of activity could be attributed primarily to a 40% reduction in the number of uptake sites. Hypoxia alone had no effect on high-affinity glutamate uptake although it reduced synaptosomal uptake of [ 3 H]3,4-dihydroxyphenyl-ethylamine. Addition of 1 mg/ml of bovine serum albumin to the incubation medium preferentia'ly stimulated high-affinity glutamate uptake in hypoxic-ischemic brain compared with its effects in normal tissue. These studies demonstrate that hypoxia-ischemia reversibly inhibits high-affinity glutamate uptake and this occurs earlier than the time required to produce neuronal damage in the model.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66361/1/j.1471-4159.1986.tb00803.x.pd

    Medical Care Capacity for Influenza Outbreaks, Los Angeles

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    In December 1997, media reported hospital overcrowding and “the worst [flu epidemic] in the past two decades” in Los Angeles County (LAC). We found that rates of pneumonia and influenza deaths, hospitalizations, and claims were substantially higher for the 1997–98 influenza season than the previous six seasons. Hours of emergency medical services (EMS) diversion (when emergency departments could not receive incoming patients) peaked during the influenza seasons studied; the number of EMS diversion hours per season also increased during the seasons 1993–94 to 1997–98, suggesting a decrease in medical care capacity during influenza seasons. Over the seven influenza seasons studied, the number of licensed beds decreased 12%, while the LAC population increased 5%. Our findings suggest that the capacity of health-care systems to handle patient visits during influenza seasons is diminishing

    Disaster Risks Research and Assessment to Promote Risk Reduction and Management

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    Natural hazard events lead to disasters when the events interact with exposed and vulnerable physical and social systems. Despite significant progress in scientific understanding of physical phenomena leading to natural hazards as well as of vulnerability and exposure, disaster losses due to natural events do not show a tendency to decrease. This tendency is associated with many factors including increase in populations and assets at risk as well as in frequency and/or magnitude of natural events, especially those related to hydro-meteorological and climatic hazards. But essentially disaster losses increase because some of the elements of the multidimensional dynamic disaster risk system are not accounted for risk assessments. A comprehensive integrated system analysis and periodic assessment of disaster risks at any scale, from local to global, based on knowledge and data/information accumulated so far, are essential scientific tools that can assist in recognition and reduction of disaster risks. This paper reviews and synthesizes the knowledge of natural hazards, vulnerabilities, and disaster risks and aims to highlight potential contributions of science to disaster risk reduction (DRR) in order to provide policy-makers with the knowledge necessary to assist disaster risk mitigation and disaster risk management (DRM)

    The atmospheric role in the Arctic water cycle: A review on processes, past and future changes, and their impacts

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    This is the final version of the article. Available from the publisher via the DOI in this record.Atmospheric humidity, clouds, precipitation, and evapotranspiration are essential components of the Arctic climate system. During recent decades, specific humidity and precipitation have generally increased in the Arctic, but changes in evapotranspiration are poorly known. Trends in clouds vary depending on the region and season. Climate model experiments suggest that increases in precipitation are related to global warming. In turn, feedbacks associated with the increase in atmospheric moisture and decrease in sea ice and snow cover have contributed to the Arctic amplification of global warming. Climate models have captured the overall wetting trend but have limited success in reproducing regional details. For the rest of the 21st century, climate models project strong warming and increasing precipitation, but different models yield different results for changes in cloud cover. The model differences are largest in months of minimum sea ice cover. Evapotranspiration is projected to increase in winter but in summer to decrease over the oceans and increase over land. Increasing net precipitation increases river discharge to the Arctic Ocean. Over sea ice in summer, projected increase in rain and decrease in snowfall decrease the surface albedo and, hence, further amplify snow/ice surface melt. With reducing sea ice, wind forcing on the Arctic Ocean increases with impacts on ocean currents and freshwater transport out of the Arctic. Improvements in observations, process understanding, and modeling capabilities are needed to better quantify the atmospheric role in the Arctic water cycle and its changes.We thank all colleagues involved in the Arctic Freshwater Synthesis (AFS) for fruitful discussions. In particular, John Walsh is acknowledged for his constructive comments on the manuscript. AFS has been sponsored by the World Climate Research Programme’s Climate and the Cryosphere project (WCRP-CliC), the International Arctic Science Committee (IASC), and the Arctic Monitoring and Assessment Programme (AMAP). The work for this paper has been supported by the Academy of Finland (contracts 259537 and 283101), the UK Natural Environment Research Council (grant NE/J019585/1), the US National Science Foundation grant ARC-1023592 and the Program “Arctic” and the Basic Research Program of the Presidium Russian Academy of Sciences. NCAR is supported by the U.S. National Science Foundation. We gratefully acknowledge the project coordination and meeting support of Jenny Baeseman and Gwenaelle Hamon at the CliC International Project Office. No new data were applied in the manuscript. Data applied for Figures 2 and 3 are available from the JRA-55 archive at http://jra. kishou.go.jp/JRA-55/index_en. html#usage

    Repeat placental growth factor-based testing in women with suspected preterm pre-eclampsia (PARROT-2): a multicentre, parallel-group, superiority, randomised controlled trial

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    Background: Placental growth factor (PlGF)-based testing has high diagnostic accuracy for predicting pre-eclampsia needing delivery, significantly reducing time to diagnosis and severe maternal adverse outcomes. The clinical benefit of repeat PlGF-based testing is unclear. We aimed to determine whether repeat PlGF-based testing (using a clinical management algorithm and nationally recommended thresholds) reduces adverse perinatal outcomes in pregnant individuals with suspected preterm pre-eclampsia. // Methods: In this multicentre, parallel-group, superiority, randomised controlled trial, done in 22 maternity units across England, Scotland, and Wales, we recruited women aged 18 years or older with suspected pre-eclampsia between 22 weeks and 0 days of gestation and 35 weeks and 6 days of gestation. Women were randomly assigned (1:1) to revealed repeat PlGF-based testing or concealed repeat testing with usual care. The intervention was not masked to women or partners, or clinicians or data collectors, due to the nature of the trial. The trial statistician was masked to intervention allocation. The primary outcome was a perinatal composite of stillbirth, early neonatal death, or neonatal unit admission. The primary analysis was by the intention-to-treat principle, with a per-protocol analysis restricted to women managed according to their allocation group. The trial was prospectively registered with the ISRCTN registry, ISRCTN 85912420. // Findings: Between Dec 17, 2019, and Sept 30, 2022, 1253 pregnant women were recruited and randomly assigned treatment; one patient was excluded due to randomisation error. 625 women were allocated to revealed repeat PlGF-based testing and 627 women were allocated to usual care with concealed repeat PlGF-based testing (mean age 32·3 [SD 5·7] years; 879 [70%] white). One woman in the concealed repeat PlGF-based testing group was lost to follow-up. There was no significant difference in the primary perinatal composite outcome between the revealed repeat PlGF-based testing group (195 [31·2%]) of 625 women) compared with the concealed repeat PlGF-based testing group (174 [27·8%] of 626 women; relative risk 1·21 [95% CI 0·95–1·33]; p=0·18). The results from the per-protocol analysis were similar. There were four serious adverse events in the revealed repeat PlGF-based testing group and six in the concealed repeat PlGF-based testing group; all serious adverse events were deemed unrelated to the intervention by the site principal investigators and chief investigator. // Interpretation: Repeat PlGF-based testing in pregnant women with suspected pre-eclampsia was not associated with improved perinatal outcomes. In a high-income setting with a low prevalence of adverse outcomes, universal, routine repeat PlGF-based testing of all individuals with suspected pre-eclampsia is not recommended. // Funding: Tommy's Charity, Jon Moulton Charitable Trust, and National Institute for Health and Care Research Guy's and St Thomas' Biomedical Research Centre
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