2,440 research outputs found

    Neonatal Respiratory Distress Syndrome as a Function of Gestational Age and the Lecithin/Sphingomyelin Ratio

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    This study was designed to derive predictive logistic regression equations to allow the risk of neonatal respiratory distress syndrome (RDS) to be defined as a function of both the lecithin/sphingomyelin (L/S) ratio and gestational age. We hypothesize that the optimal cutoff value will vary significantly depending on gestational age, and that our data will support the need to account for gestational age when interpreting test results. Data was collected via a retrospective chart review. Women who underwent amniocentesis for the purpose of assessing fetal lung maturity at Yale-New Haven Hospital from 1998 to 2004 were identified and included if delivery of a liveborn, singleton, non-anomalous infant occurred within 72 hours of the lecithin/sphingomyelin ratio assay. Maternal and neonatal data were collected regarding demographics, pregnancy complications and neonatal outcomes, including respiratory distress syndrome. A total of 210 mother-neonate pairs met criteria for analysis, with 8 cases of RDS. Both gestational age and L/S ratio were independent predictors of RDS. By modeling the odds of RDS using logistic regression, a probability of RDS approximating 10% was noted at an L/S cutoff of 3.6 at 32 weeks, 2.8 at 34 weeks, 1.8 at 36 weeks, and 1.4 at term. Under 32 weeks of gestation a probability as low as 10% was not observed by this model. We conclude that stratifying risk of neonatal RDS using both the L/S ratio and gestational age may aid in clinical decision-making concerning the timing of delivery

    Nitrogen oxides and PAN in plumes from boreal fires during ARCTAS-B and their impact on ozone: an integrated analysis of aircraft and satellite observations

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    We determine enhancement ratios for NO_x, PAN, and other NO_y species from boreal biomass burning using aircraft data obtained during the ARCTAS-B campaign and examine the impact of these emissions on tropospheric ozone in the Arctic. We find an initial emission factor for NO_x of 1.06 g NO per kg dry matter (DM) burned, much lower than previous observations of boreal plumes, and also one third the value recommended for extratropical fires. Our analysis provides the first observational confirmation of rapid PAN formation in a boreal smoke plume, with 40% of the initial NO_x emissions being converted to PAN in the first few hours after emission. We find little clear evidence for ozone formation in the boreal smoke plumes during ARCTAS-B in either aircraft or satellite observations, or in model simulations. Only a third of the smoke plumes observed by the NASA DC8 showed a correlation between ozone and CO, and ozone was depleted in the plumes as often as it was enhanced. Special observations from the Tropospheric Emission Spectrometer (TES) also show little evidence for enhanced ozone in boreal smoke plumes between 15 June and 15 July 2008. Of the 22 plumes observed by TES, only 4 showed ozone increasing within the smoke plumes, and even in those cases it was unclear that the increase was caused by fire emissions. Using the GEOS-Chem atmospheric chemistry model, we show that boreal fires during ARCTAS-B had little impact on the median ozone profile measured over Canada, and had little impact on ozone within the smoke plumes observed by TES

    Redox Pioneer: Professor Joe M. McCord

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    Dr. Joe McCord (Ph.D. 1970) is recognized here as a Redox Pioneer because he has published at least three articles on antioxidant/redox biology as first/last author that have been cited over 1000 times and has published at least 37 articles each cited over 100 times. Dr. McCord is known for the monumental discovery of the antioxidant superoxide dismutase (SOD) while a graduate student under fellow redox pioneer Irwin Fridovich and demonstrating its necessity to aerobic life. Beyond this, McCord\u27s career is distinguished for bridging the gap from basic science to clinical relevance by showing the application of SOD and superoxide to human physiology, and characterizing the physiological functions of superoxide in inflammation, immunological chemotaxis, and ischemia-reperfusion injury, among other disease conditions. Work by McCord serves as the foundation upon which our understanding of how superoxide functions in a variety of physiological systems is built and demonstrates how superoxide is essential to aerobic life, yet, if left unchecked by SOD, toxic to a multitude of systems. These discoveries have substantial significance in a wide range of studies with applications in cardiovascular disease, cancer, neurology, and medicine, as well as general health and longevity. Dr. McCord\u27s contributions to free radical biology have been recognized through many prestigious achievement awards, honorary titles, and conferences around the world; each serving as a testament to his status as a redox pioneer

    Deduction of a Functional Dependency from a Set of Functional Dependencies

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    This paper describes an algorithm called the Deduction Tracing Algorithm (DTA) which utilizes basic properties of functional dependencies from database systems and a modification of a tree search algorithm from artificial intelligence. The algorithm takes a set of functional dependencies, F, along with a specific functional dependency L → R as input and produces a list of functional dependencies from F that can be used to deduce L → R. The resulting algorithm is easily automated to provide relational database users with a tool for organizing their queries

    Chemical ionization tandem mass spectrometer for the in situ measurement of methyl hydrogen peroxide

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    A new approach for measuring gas-phase methyl hydrogen peroxide [(MHP) CH_3OOH] utilizing chemical ionization mass spectrometry is presented. Tandem mass spectrometry is used to avoid mass interferences that hindered previous attempts to measure atmospheric CH_3OOH with CF_3O− clustering chemistry. CH_3OOH has been successfully measured in situ using this technique during both airborne and ground-based campaigns. The accuracy and precision for the MHP measurement are a function of water vapor mixing ratio. Typical precision at 500 pptv MHP and 100 ppmv H_2O is ±80 pptv (2 sigma) for a 1 s integration period. The accuracy at 100 ppmv H_2O is estimated to be better than ±40%. Chemical ionization tandem mass spectrometry shows considerable promise for the determination of in situ atmospheric trace gas mixing ratios where isobaric compounds or mass interferences impede accurate measurements

    Urban agriculture in shared spaces : the difficulties with collaboration in an age of austerity

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    The expanding critical literature on Urban Agriculture (UA) makes links between the withdrawal of state services and the institutionalisation of volunteering, while observing that challenging funding landscapes can foster competitive environments between third sector organisations. Where these organisations are forced to compete for survival at the expense of collaboration, their ability to collectively upscale and expand beneficial activities can be compromised. This paper focuses on a lottery-funded UA project and draws predominantly on observations and interviews held with project staff and growing group volunteers. Research conducted in Wythenshawe, Manchester (UK), highlights difficulties experienced by organisations attempting to function in an environment disfigured by depletion, illustrating conflicts that can arise between community groups and charitable organisations competing for space and resources. Inter-organisational dynamics are considered at two scales; at the grassroots level between growing groups, and at a structural level between project partners. In a landscape scarred by local authority cutbacks and restructures, a dearth of funding opportunities and increasingly precarious employment, external initiatives can be met with suspicion or hostility, particularly when viewed as superfluous interventions. The resulting “siege mentality” reflects the need for organisational self-preservation but perhaps paradoxically results in groups with similar goals and complementary ideologies working against each other rather than in cooperation. Keywords: Urban Agriculture; critical geography; neoliberalism; community growing; urban farmin
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