329 research outputs found

    Dispersant Efficacy and Effectiveness

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    Dispersants have been researched extensively and used for oil spill mitigation for more than 40 years, yet there are opportunities to enhance our understanding, including with respect to their long term fate and effects and how to optimize dispersant use. For example, the 2005 National Academy of Sciences report, Understanding Oil Spill Dispersants: Efficacy and Effects, suggested a number of areas where increased understanding would help support the use of dispersants. Throughout the summer of 2010 dispersants were used in unprecedented quantities and, in the case of sub-sea application, with novel application methods following the Deepwater Horizon incident. The focus of this paper is to provide a brief overview of spilled oil behavior, chemical dispersants efficacy and effectiveness, and a discussion of the state of knowledge pre-, during, and post- Deepwater Horizon

    Field Test of the Cougar Home Safety Assessment for Older Persons Version 1.0

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    After reviewing the literature on environmental safety and existing home safety evaluation tools, the researchers developed the Cougar Home Safety Assessment Version 1.0 (Cougar 1.0). This assessment is a 56-item tool for identifying environmental safety hazards in the homes of older persons. The first purpose of this study was to develop and field test the Cougar 1.0 to determine its inter-rater reliability and validity. The second purpose was to identify specific environmental safety hazards in the residences of older persons during the field test. Three graduate occupational therapy students administered the Cougar 1.0 in the homes of 14 older persons within one county of northeastern Pennsylvania. The instrument was found to have a moderate level of inter-rater reliability, as Cohen’s Kappa for the ratings of the 3 raters was .506. Percent agreement between the three raters was 90 percent. The field test found that the most frequently unsafe aspects of the homes were: a lack of grab bars near toilets; no emergency numbers posted near phones; the presence of non-grip throw rugs; lack of fire extinguishers; and lack of step stools. Participating residents and occupational therapy home safety specialists provided positive feedback regarding the content validity of the Cougar 1.0. This research suggests that the use of this instrument by occupational therapists may prevent client injuries in the home

    Molecular characterization and in silico expression analysis of a chalcone synthase gene family in Sorghum bicolor

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    Recent use of Sorghum bicolor as a target for grass genomics has presented new resources for gene discovery in novel metabolic pathways in Poaceae. Sorghum synthesizes a unique class of flavonoid phytoalexins, the 3-deoxyanthocyanidins, in response to fungal infection. The biosynthetic pathways for 3-deoxyflavonoids are largely uncharacterized but are known to involve transcriptional activation of chalcone synthase (CHS). CHS, or naringenin CHS, catalyses the formation of naringenin, the precursor for different flavonoids. We have isolated seven sorghum CHS genes, CHS1-7, from a genomic library on high-density filters. CHS1-7 are highly conserved and closely related to the maize C2 and Whp genes. Several of them are also linked in the genome. These findings suggest that they are the result of recent gene duplication events. Expression of the individual CHS genes was studied in silico by examination of expressed sequence tag (EST) data available in the public domain. Our analyses suggested that CHS1-7 were not differentially expressed in the various growth and developmental conditions represented by the cDNA libraries used to generate the EST data. However, we identified a CHS-like gene, CHS8, with significantly higher EST abundance in the pathogen-induced library. CHS8 shows only 81-82% identity to CHS1-7 and forms a distinct subgroup in our phylogenetic analysis. In addition, the active site region contains substitutions that distinguish CHS8 from naringenin CHS. We propose that CHS8 has evolved new enzymatic functions that are involved in the synthesis of defence-related flavonoids, such as the 3-deoxyanthocyanidins, during fungal infection. © 2002 Elsevier Science Ltd. All rights reserved.postprin

    Evaluation of an exercise field test using heart rate monitors to assess cardiorespiratory fitness and heart rate recovery in an asymptomatic population.

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    PurposeMeasures of cardiorespiratory fitness (CRF) and heart rate recovery (HRR) can improve risk stratification for cardiovascular disease, but these measurements are rarely made in asymptomatic individuals due to cost. An exercise field test (EFT) to assess CRF and HRR would be an inexpensive method for cardiovascular disease risk assessment in large populations. This study assessed 1) the predictive accuracy of a 12-minute run/walk EFT for estimating CRF ([Formula: see text]) and 2) the accuracy of HRR measured after an EFT using a heart rate monitor (HRM) in an asymptomatic population.MethodsFifty subjects (48% women) ages 18-45 years completed a symptom-limited exercise tolerance test (ETT) (Bruce protocol) and an EFT on separate days. During the ETT, [Formula: see text] was measured by a metabolic cart, and heart rate was measured continuously by a HRM and a metabolic cart.ResultsEFT distance and sex independently predicted[Formula: see text]. The average absolute difference between observed and predicted [Formula: see text] was 0.26 ± 3.27 ml·kg-1·min-1 for our model compared to 7.55 ± 3.64 ml·kg-1·min-1 for the Cooper model. HRM HRR data were equivalent to respective metabolic cart values during the ETT. HRR at 1 minute post-exercise during ETT compared to the EFT had a moderate correlation (r=0.75, p<0.001).ConclusionA more accurate model to estimate CRF from a 12-minute run/walk EFT was developed, and HRR can be measured using a HRM in an asymptomatic population outside of clinical settings

    Developing a universal single-use skid for continuous purification operations

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    High-Q-factor Al [subscript 2]O[subscript 3] micro-trench cavities integrated with silicon nitride waveguides on silicon

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    We report on the design and performance of high-Q integrated optical micro-trench cavities on silicon. The microcavities are co-integrated with silicon nitride bus waveguides and fabricated using wafer-scale silicon-photonics-compatible processing steps. The amorphous aluminum oxide resonator material is deposited via sputtering in a single straightforward post-processing step. We examine the theoretical and experimental optical properties of the aluminum oxide micro-trench cavities for different bend radii, film thicknesses and near-infrared wavelengths and demonstrate experimental Q factors of > 10[superscript 6]. We propose that this high-Q micro-trench cavity design can be applied to incorporate a wide variety of novel microcavity materials, including rare-earth-doped films for microlasers, into wafer-scale silicon photonics platforms

    An analytical study of the diffusion kinetics of a radiation-induced chemical reaction system

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    Call number: LD2668 .T4 1968 C664Master of Scienc
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