243 research outputs found

    Evidence for a Climate-Driven Hydrologic Regime Shift in the Canadian Columbia Basin

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    Water resources from the Columbia River Basin are intensely used for domestic, agricultural, industrial and hydroelectric generation needs. Water availability in the Pacific Northwest is influenced by several ocean–atmosphere modes of climate variability that occur in the Pacific Ocean. Climate change has the potential to alter these relationships and influence both the volume and timing of streamflow in the snowmelt-dominated tributaries to the Columbia River. Here, the historical influences of climate variability and recent climate warming on the volume and timing of streamflow for 40 tributary streams in the Columbia River Basin of Canada were evaluated. Regional relationships were found between streamflow and several Pacific Ocean climate indices, including the already established relationships with the Pacific Decadal Oscillation (PDO) and El Nino/Southern Oscillation (ENSO). However, in recent decades the statistical relationship between streamflow and climate indices has become weaker, which has implications for managers using these indices as decision-making tools. A comparison of the average annual streamflow for the cool PDO phase, which occurred from 1947 to 1976, to the more recent cool phase from 1999 to 2011 indicates a 11% decline across the Canadian portion of the basin. Removing the influence of these climate indices on historical streamflow reveals decreases in the residual streamflow beginning sometime in the 1980s. The potential role of increased temperatures on streamflow was investigated, and statistically significant relationships between decreased streamflow and increased temperatures in the summer months were found, particularly with the number of days over 18°C. The results suggest that climate change may be altering the historical relationship between climate indices and streamflow in the Canadian portion of the Columbia Basin

    The Forum: Winter 2001

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    Winter 2001 journal of the Honors Program at the University of North Dakota. The issue includes stories, poems, essays and art by undergraduate students.https://commons.und.edu/und-books/1047/thumbnail.jp

    The Forum: Spring 2002

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    Spring 2002 journal of the Honors Program at the University of North Dakota. The issue includes stories, poems, essays and art by undergraduate students.https://commons.und.edu/und-books/1048/thumbnail.jp

    The Effects of Age, Exposure History and Malaria Infection on the Susceptibility of Anopheles Mosquitoes to Low Concentrations of Pyrethroid

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    Chemical insecticides are critical components of malaria control programs. Their ability to eliminate huge numbers of mosquitoes allows them to swiftly interrupt disease transmission, but that lethality also imposes immense selection for insecticide resistance. Targeting control at the small portion of the mosquito population actually responsible for transmitting malaria parasites to humans would reduce selection for resistance, yet maintain effective malaria control. Here, we ask whether simply lowering the concentration of the active ingredient in insecticide formulations could preferentially kill mosquitoes infected with malaria and/or those that are potentially infectious, namely, old mosquitoes. Using modified WHO resistance-monitoring assays, we exposed uninfected Anopheles stephensi females to low concentrations of the pyrethroid permethrin at days 4, 8, 12, and 16 days post-emergence and monitored survival for at least 30 days to evaluate the immediate and long-term effects of repeated exposure as mosquitoes aged. We also exposed Plasmodium chabaudi- and P. yoelii-infected An. stephensi females. Permethrin exposure did not consistently increase mosquito susceptibility to subsequent insecticide exposure, though older mosquitoes were more susceptible. A blood meal slightly improved survival after insecticide exposure; malaria infection did not detectably increase insecticide susceptibility. Exposure to low concentrations over successive feeding cycles substantially altered cohort age-structure. Our data suggest the possibility that, where high insecticide coverage can be achieved, low concentration formulations have the capacity to reduce disease transmission without the massive selection for resistance imposed by current practice

    Short- and long-term cost and utilization of health care resources in Parkinson's disease in the UK

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    Background: There is currently no robust long‐term data on costs of treating patients with Parkinson's disease. The objective of this study was to report levels of health care utilization and associated costs in the 10 years after diagnosis among PD patients in the United Kingdom. Methods: We undertook a retrospective population‐based cohort study using linked data from the UK Clinical Practice Research Datalink and Hospital Episode Statistics databases. Total health care costs of PD patients were compared with those of a control group of patients without PD selected using 1:1 propensity score matching based on age, sex, and comorbidity. Results: Between 1994 and 2013, 7271 PD patients who met study inclusion criteria were identified in linked Clinical Practice Research Datalink‐Hospital Episode Statistics; 7060 were matched with controls. The mean annual health care cost difference (at 2013 costs) between PD patients and controls was £2471 (US3716) per patient in the first year postdiagnosis (P < 0.001), increasing to £4004 (US6021) per patient (P &lt; 0.001) 10 years following diagnosis because of higher levels of use across all categories of health care utilization. Costs in patients with markers of advanced PD (ie, presence of levodopa‐equivalent daily dose &gt; 1100 mg, dyskinesias, falls, dementia, psychosis, hospital admission primarily due to PD, or nursing home placement) were on average higher by £1069 (US$1608) per patient than those with PD without these markers. Conclusions: This study provides comprehensive estimates of health care costs in PD patients based on routinely collected data. Health care costs attributable to PD increase in the year following diagnosis and are higher for patients with indicators of advanced disease

    Short Lag Times for Invasive Tropical Plants: Evidence from Experimental Plantings in Hawai'i

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    Background: The lag time of an invasion is the delay between arrival of an introduced species and its successful spread in a new area. To date, most estimates of lag times for plants have been indirect or anecdotal, and these estimates suggest that plant invasions are often characterized by lag times of 50 years or more. No general estimates are available of lag times for tropical plant invasions. Historical plantings and documentation were used to directly estimate lag times for tropical plant invasions in Hawai’i. Methodology/Principal Findings: Historical planting records for the Lyon Arboretum dating back to 1920 were examined to identify plants that have since become invasive pests in the Hawaiian Islands. Annual reports describing escape from plantings were then used to determine the lag times between initial plantings and earliest recorded spread of the successful invaders. Among 23 species that eventually became invasive pests, the average lag time between introduction and first evidence of spread was 14 years for woody plants and 5 years for herbaceous plants. Conclusions/Significance: These direct estimates of lag times are as much as an order of magnitude shorter than previous, indirect estimates, which were mainly based on temperate plants. Tropical invaders may have much shorter lag times than temperate species. A lack of direct and deliberate observations may have also inflated many previous lag time estimates. Although there have been documented cases of long lag times due to delayed arrival of a mutualist or environmenta

    Hand washing with soap and water together with behavioural recommendations prevents infections in common work environment: an open cluster-randomized trial

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    <p>Abstract</p> <p>Background</p> <p>Hand hygiene is considered as an important means of infection control. We explored whether guided hand hygiene together with transmission-limiting behaviour reduces infection episodes and lost days of work in a common work environment in an open cluster-randomized 3-arm intervention trial.</p> <p>Methods</p> <p>A total of 21 clusters (683 persons) were randomized to implement hand hygiene with soap and water (257 persons), with alcohol-based hand rub (202 persons), or to serve as a control (224 persons). Participants in both intervention arms also received standardized instructions on how to limit the transmission of infections. The intervention period (16 months) included the emergence of the 2009 influenza pandemic and the subsequent national hand hygiene campaign influencing also the control arm.</p> <p>Results</p> <p>In the total follow-up period there was a 6.7% reduction of infection episodes in the soap-and water arm (p = 0.04). Before the onset of the anti-pandemic campaign, a statistically significant (p = 0.002) difference in the mean occurrence of infection episodes was observed between the control (6.0 per year) and the soap-and-water arm (5.0 per year) but not between the control and the alcohol-rub arm (5.6 per year). Neither intervention had a decreasing effect on absence from work.</p> <p>Conclusions</p> <p>We conclude that intensified hand hygiene using water and soap together with behavioural recommendations can reduce the occurrence of self-reported acute illnesses in common work environment. Surprisingly, the occurrence of reported sick leaves also increased in the soap-and water-arm.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov: <a href="http://www.clinicaltrials.gov/ct2/show/NCT00981877">NCT00981877</a></p> <p>Source of funding</p> <p>The Finnish Work Environment Fund and the National Institute for Health and Welfare.</p
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