Assessment of impact of climate change on water resources: a long term analysis of the Great Lakes of North America

International audienceIn the threshold of the appearance of global warming from theory to reality, extensive research has focused on predicting the impact of potential climate change on water resources using results from Global Circulation Models (GCMs). This research carries this further by statistical analyses of long term meteorological and hydrological data. Seventy years of historical trends in precipitation, temperature, and streamflows in the Great Lakes of North America are developed using long term regression analyses and Mann-Kendall statistics. The results generated by the two statistical procedures are in agreement and demonstrate that many of these variables are experiencing statistically significant increases over a seven-decade period. The trend lines of streamflows in the three rivers of St. Clair, Niagara and St. Lawrence, and precipitation levels over four of the five Great Lakes, show statistically significant increases in flows and precipitation. Further, precipitation rates as predicted using fitted regression lines are compared with scenarios from GCMs and demonstrate similar forecast predictions for Lake Superior. Trend projections from historical data are higher than GCM predictions for Lakes Michigan/Huron. Significant variability in predictions, as developed from alternative GCMs, is noted. Given the general agreement as derived from very different procedures, predictions extrapolated from historical trends and from GCMs, there is evidence that hydrologic changes particularly for the precipitation in the Great Lakes Basin may be demonstrating influences arising from global warming and climate change

Assessment of impacts of climate change on water resources ? a case study of the Great Lakes of North America

International audienceHistorical trends in precipitation, temperature, and streamflows in the Great Lakes are examined using regression analysis and Mann-Kendall statistics, with the result that many of these variables demonstrate statistically significant increases ongoing for a six decade period. Future precipitation rates as predicted using fitted regression lines are compared with scenarios from Global Climate Change Models (GCMs) and demonstrate similar forecast predictions for Lake Superior. Trend projections from historical data are, however, higher than GCM predictions for Michigan/Huron. Significant variability in predictions, as developed from alternative GCMs, is noted. Given the general agreement as derived from very different procedures, predictions extrapolated from historical trends and from GCMs, there is evidence that hydrologic changes in the Great Lakes Basin are likely the result of climate change

Controlling the properties of InGaAs quantum dots by selective-area epitaxy

Selective growth of InGaAsquantum dots on GaAs is reported. It is demonstrated that selective-area epitaxy can be used for in-plane bandgap energy control of quantum dots.Atomic force microscopy and cathodoluminescence are used for characterization of the selectively growndots. Our results show that the composition, size, and uniformity of dots are determined by the dimensions of the mask used for patterning the substrate. Properties of dots can be selectively tuned by varying the mask dimensions. A single-step growth of a thin InGaAsquantum well and InGaAsquantum dots on the same wafer is demonstrated. By using a single-step growth,dots luminescing at different wavelengths, in the range 1150–1230nm, in different parts of the same wafer are achieved.The Australian Research Council is gratefully acknowledged for the financial support

Thermal Investigation of Stormwater Management Ponds

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 Water Utility Risk Integration Matrix: Demonstrating Potential for an Integrated Approach to Municipal Water Management

Abstract Municipal water utilities traditionally have been managed in isolation with little consideration of common factors affecting risk. An integrated approach to municipal water management has great potential for increasing the resilience of these systems under future uncertainties. In a recent survey conducted by the University of Guelph, respondents from various Canadian municipalities identified aging infrastructure, climate change and urbanization as the top three drivers of risk to water infrastructure. To demonstrate the potential for an integrated approach to risk management of water infrastructure, the Water Utility Risk Integration Matrix document was developed. This interactive document emphasizes commonalities across municipal water sectors and allows users to quickly access relevant information on the previously identified drivers of risk. Each chapter provides an overview of the impact each driver has on water treatment and distribution, sewage conveyance and treatment, combined sewer systems, and stormwater conveyance. The document provides direct access to additional details and external webpages containing statistics and examples for any implications of interest to the user. Relevant guidance and case studies are also incorporated into the document with links to external data sources. This document facilitates information gathering to assist in the widespread adoption of an integrated approach to risk management of municipal water utilities and provides a framework for further development of risk management initiatives

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

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

Measuring the Performance of Vaccination Programs Using Cross-Sectional Surveys: A Likelihood Framework and Retrospective Analysis

Justin Lessler and colleagues describe a method that estimates the fraction of a population accessible to vaccination activities, and they apply it to measles vaccination in three African countries: Ghana, Madagascar, and Sierra Leone

Medical Care Capacity for Influenza Outbreaks, Los Angeles

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

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

: 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