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Search Results: 1 - 10 of 7207 matches for " Erin Johnson "
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Exposure Assessment of Ambient Sulfur Dioxide Downwind of an Oil Refinery in Cura?ao  [PDF]
Erin L. Pulster, Giffe Johnson, Dave Hollander, James McCluskey, Raymond Harbison
Journal of Environmental Protection (JEP) , 2018, DOI: 10.4236/jep.2018.93014
Abstract: Primary sources of atmospheric sulfur dioxide are anthropogenic activities associated with the burning of fossil fuels and industrial processes that may have associations with various morbidities and mortalities. As such, several regional and global regulatory agencies have recommended ambient air limits to reduce environmental exposures. The objectives of this study were to evaluate ambient levels of sulfur dioxide surrounding an oil refinery on the island of Cura?ao. Levels which were then compared to literature values and recommended public health guidelines to determine potential public health risks. Concentrations of sulfur dioxide in Curacao were found to be among the highest globally with an increasing trend over time. While the epidemiological evidence does not conclusively suggest there is a health risk from these levels of exposure, SO2 concentrations greatly exceed regulatory and guidance levels and suggest that further emissions control is warranted. Future recommendations include a more rigorous epidemiological study in Cura?ao and expand the air monitoring efforts to include areas upwind of the refinery as well as additional petrochemical emissions.
Assessment of Inhalable Particulate Matter Associated with a Refinery in Curaçao  [PDF]
Erin L. Pulster, Giffe Johnson, Dave Hollander, James McCluskey, Raymond Harbison
Journal of Environmental Protection (JEP) , 2018, DOI: 10.4236/jep.2018.910069
Abstract: Inhalation and atmospheric pollution studies have focused on particulate matter due to correlations and associations with various morbidities and mortalities. This research analyzed ambient concentrations of inhalable particulate matter (PM10) on the island of Curaçao in order to evaluate through comparative literature analysis and recommended public health guidelines the potential health risks. Available hourly, daily and monthly PM10 measurements were accessed from June 2010 through December 2014 from a local air monitoring station in Willemstad. Mean annual concentrations of PM10 (31 - 122 μg/m3) in Curaçao are among the highest reported globally, demonstrating an increasing trend over time and exceed current public health guidelines recommended by local and international agencies. While the epidemiological evidence is inadequate to infer a causal association between health effects and long-term exposures of the measured PM10 concentrations, the results indicate that emissions controls are not adequate for compliance with international exposure standards.
Levels and Sources of Atmospheric Polycyclic Aromatic Hydrocarbons Surrounding an Oil Refinery in Cura?ao  [PDF]
Erin L. Pulster, Giffe Johnson, Dave Hollander, James McCluskey, Raymond Harbison
Journal of Environmental Protection (JEP) , 2019, DOI: 10.4236/jep.2019.103025
Abstract: This research measured ambient levels of polycyclic aromatic hydrocarbons (PAHs) surrounding a petrochemical complex on the island of Curacao using passive air sampling. In addition, source elucidation of PAHs was conducted using concentration profiles, distribution profiles, binary diagnostic ratios and factor analysis. Passive air samplers with polyurethane foam collection disks (PAS-PUFs) were deployed in 2011 (n = 43) and in 2014 (n = 30) to evaluate the extent of the emission plume as well as spatial and temporal differences in ambient PAH concentrations. In general, ambient PAH concentrations in Curacao were consistent with other urban and industrialized regions of the world; however, the levels measured downwind of Isla Refineriá petrochemical complex were among some of the highest reported ambient PAHs globally. Ambient PAH concentrations ranged from 1.2 to 790 ng/m3 in 2011 and 27 to 660 ng/m3 in 2014, demonstrating no temporal differences. However, significant spatial differences were detected between samples collected upwind and downwind of the petrochemical complex. Significantly higher ambient PAH concentrations were found in the samples collected downwind of the petrochemical complex compared to those upwind in 2014 (p < 0. 0001). Source elucidation revealed the ambient PAHs downwind were dominated by petrogenic emission sources and to a lesser degree pyrogenic emissions, whereas, the upwind locations appear to be equally influenced by both petrogenic and pyrogenic emissions sources.

Squares from D(–4) and D(20) Triples  [PDF]
Zvonko ?erin
Advances in Pure Mathematics (APM) , 2011, DOI: 10.4236/apm.2011.15052
Abstract: We study the eight infinite sequences of triples of natural numbers A=(F2n+1,4F2n+3,F2n+7), B=(F2n+1,4F2n+5,F2n+7), C=(F2n+1,5F2n+1,F2n+3), D=(F2n+3,4F2n+1,F2n+3) and A=(L2n+1,4L2n+3,L2n+7), B=(L2n+1,4L2n+5,L2n+7), C=(L2n+1,5L2n+1,L2n+3), D=(L2n+3,4L2n+1,L2n+3. The sequences A,B,C and D are built from the Fibonacci numbers Fn while the sequences A, B, C and D from the Lucas numbers Ln. Each triple in the sequences A,B,C and D has the property D(-4) (i. e., adding -4 to the product of any two different components of them is a square). Similarly, each triple in the sequences A, B, C and D has the property D(20). We show some interesting properties of these sequences that give various methods how to get squares from them.
Evidence That a RecQ Helicase Slows Senescence by Resolving Recombining Telomeres
Julia Y. Lee,Marina Kozak,Joel D. Martin,Erin Pennock,F. Brad Johnson
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.0050160
Abstract: RecQ helicases, including Saccharomyces cerevisiae Sgs1p and the human Werner syndrome protein, are important for telomere maintenance in cells lacking telomerase activity. How maintenance is accomplished is only partly understood, although there is evidence that RecQ helicases function in telomere replication and recombination. Here we use two-dimensional gel electrophoresis (2DGE) and telomere sequence analysis to explore why cells lacking telomerase and Sgs1p (tlc1 sgs1 mutants) senesce more rapidly than tlc1 mutants with functional Sgs1p. We find that apparent X-shaped structures accumulate at telomeres in senescing tlc1 sgs1 mutants in a RAD52- and RAD53-dependent fashion. The X-structures are neither Holliday junctions nor convergent replication forks, but instead may be recombination intermediates related to hemicatenanes. Direct sequencing of examples of telomere I-L in senescing cells reveals a reduced recombination frequency in tlc1 sgs1 compared with tlc1 mutants, indicating that Sgs1p is needed for tlc1 mutants to complete telomere recombination. The reduction in recombinants is most prominent at longer telomeres, consistent with a requirement for Sgs1p to generate viable progeny following telomere recombination. We therefore suggest that Sgs1p may be required for efficient resolution of telomere recombination intermediates, and that resolution failure contributes to the premature senescence of tlc1 sgs1 mutants.
Evidence That a RecQ Helicase Slows Senescence by Resolving Recombining Telomeres
Julia Y Lee,Marina Kozak,Joel D Martin,Erin Pennock,F. Brad Johnson
PLOS Biology , 2007, DOI: 10.1371/journal.pbio.0050160
Abstract: RecQ helicases, including Saccharomyces cerevisiae Sgs1p and the human Werner syndrome protein, are important for telomere maintenance in cells lacking telomerase activity. How maintenance is accomplished is only partly understood, although there is evidence that RecQ helicases function in telomere replication and recombination. Here we use two-dimensional gel electrophoresis (2DGE) and telomere sequence analysis to explore why cells lacking telomerase and Sgs1p (tlc1 sgs1 mutants) senesce more rapidly than tlc1 mutants with functional Sgs1p. We find that apparent X-shaped structures accumulate at telomeres in senescing tlc1 sgs1 mutants in a RAD52- and RAD53-dependent fashion. The X-structures are neither Holliday junctions nor convergent replication forks, but instead may be recombination intermediates related to hemicatenanes. Direct sequencing of examples of telomere I-L in senescing cells reveals a reduced recombination frequency in tlc1 sgs1 compared with tlc1 mutants, indicating that Sgs1p is needed for tlc1 mutants to complete telomere recombination. The reduction in recombinants is most prominent at longer telomeres, consistent with a requirement for Sgs1p to generate viable progeny following telomere recombination. We therefore suggest that Sgs1p may be required for efficient resolution of telomere recombination intermediates, and that resolution failure contributes to the premature senescence of tlc1 sgs1 mutants.
Feasibility of Dual-Task Gait Training for Community-Dwelling Adults after Stroke: A Case Series
Prudence Plummer,Raymond M. Villalobos,Moira S. Vayda,Myriam Moser,Erin Johnson
Stroke Research and Treatment , 2014, DOI: 10.1155/2014/538602
Abstract: This case series explored the feasibility and efficacy of cognitive-motor dual-task gait training in community-dwelling adults within 12 months of stroke. A secondary aim was to assess transfer of training to different dual-task combinations. Seven male participants within 12 months of stroke participated in 12 sessions of dual-task gait training. We examined single and dual-task performance in four different dual-task combinations at baseline, after 6 and 12 sessions, and if possible, at 1-month followup. Feasibility was assessed by asking participants to rate mental and physical fatigue, perceived difficulty, anxiety, and fear of falling at the end of each session. Five of the seven participants demonstrated reduced dual-task cost in gait speed in at least one of the dual-task combinations after the intervention. Analysis of the patterns of interference in the gait and cognitive tasks suggested that the way in which the participants allocated their attention between the simultaneous tasks differed across tasks and, in many participants, changed over time. Dual-task gait training is safe and feasible within the first 12 months after stroke, and may improve dual-task walking speed. Individuals with a combination of physical and cognitive impairments may not be appropriate for dual-task gait training. 1. Introduction Cognitive-motor dual-task interference, defined as the decrement in performance that occurs when cognitive and motor tasks are performed simultaneously, has been well established in people after stroke [1–9]. This growing body of research has demonstrated significant dual-task decrements in gait speed [1, 5, 8], stride length [5, 8], cadence [6, 8], stride duration [2, 4, 8], and double limb support duration [1, 7]. In other words, compared to single-task walking, when individuals with stroke perform a cognitive task while walking they are less stable and take shorter, slower steps, resulting in a dramatic cost on gait speed. Gait-related dual-task deficits persist in community-dwelling stroke survivors many months after discharge from rehabilitation [3, 5, 8]. Since walking in the community is often performed concurrently with cognitive tasks, such as remembering directions or engaging in social interactions, a reduced capacity for dual-task walking may restrict the degree to which a person is able to physically function and participate in their life roles. Conventional rehabilitation does not appear to adequately address gait-related dual-task interference. For example, in a longitudinal study of cognitive-motor interference, Cockburn and
External Mill Monitoring of Wheat Flour Fortification Programs: An Approach for Program Managers Using Experiences from Jordan
James P. Wirth,Erin Nichols,Hanan Mas'd,Rawhieh Barham,Quentin W. Johnson,Mary Serdula
Nutrients , 2013, DOI: 10.3390/nu5114741
Abstract: The fortification of wheat flour with micronutrients is a common strategy to increase vitamin and mineral intake. While wheat flour mills are often inspected by agencies affiliated with national ministries to ensure compliance with national fortification standards, few countries use data derived from these inspections to construct an external monitoring system for use in program management and evaluation. The primary objective of this paper is to assess the performance of the external monitoring system utilized in Jordan according to the US Centers for Disease Control and Prevention’s Updated Guidelines for Evaluating Public Health Surveillance Systems. A secondary objective is to present mill monitoring results from 2009 to 2010 in order to demonstrate the data generated by the system. The review concludes that the data required for the system is representative, simple to collect, and can be collected in a flexible manner. The external monitoring system is acceptable to participating agencies and millers and is stable due to mandatory fortification legislation which provides the legal framework for external monitoring. Data on production of fortified flour and utilization of premix can be provided in a timely manner, but on-site mill monitoring and flour sample collection are more challenging due to resource constraints. The frequent collection of a small number of indicators can provide fortification program managers with timely information with which to base decisions. Jordan’s external monitoring system successfully documented the performance of each mill and the entire flour fortification program, and can serve as a model for other national fortification programs considering external monitoring approaches.
Reporting, Reviewing, and Responding to Harassment on Twitter
J. Nathan Matias,Amy Johnson,Whitney Erin Boesel,Brian Keegan,Jaclyn Friedman,Charlie DeTar
Computer Science , 2015,
Abstract: When people experience harassment online, from individual threats or invective to coordinated campaigns of harassment, they have the option to report the harassers and content to the platform where the harassment has occurred. Platforms then evaluate harassment reports against terms of use and other policies to decide whether to remove content or take action against the alleged harasser--or not. On Twitter, harassing accounts can be deleted entirely, suspended (with content made unavailable pending appeal or specific changes), or sent a warning. Some platforms, including Twitter and YouTube, grant authorized reporters or trusted flaggers special privileges to identify and report inappropriate content on behalf of others. In November 2014, Twitter granted Women, Action, and the Media (WAM!) this authorized reporter status. In three weeks, WAM! reviewers assessed 811 incoming reports of harassment and escalated 161 reports to Twitter, ultimately seeing Twitter carry out 70 account suspensions, 18 warnings, and one deleted account. This document presents findings from this three-week project; it draws on both quantitative and qualitative methods. Findings focus on the people reporting and receiving harassment, the kinds of harassment that were reported, Twitter's response to harassment reports, the process of reviewing harassment reports, and challenges for harassment reporting processes.
Identification of a 12-Gene Signature for Lung Cancer Prognosis through Machine Learning  [PDF]
Erin Bard, Wei Hu
Journal of Cancer Therapy (JCT) , 2011, DOI: 10.4236/jct.2011.22017
Abstract: Personalized medicine is critical for lung cancer treatment. Different gene signatures that can classify lung cancer patients as high- or low-risk for cancer recurrence have been found. The aim of this study is to identify a novel gene signature that has higher recurrence risk prediction accuracy for non-small cell lung cancer patients than previous re-search, which can clearly differentiate the high- and low-risk groups. To accomplish this we employed an ensemble of feature selection algorithms, an ensemble of classification algorithms, and a genetic algorithm, an evolutionary search algorithm. Compared to one previous study, our 12-gene signature more accurately classifies the patients in the training set (n = 256), 57.32% compared to 50.78%, as well as in the two test sets (n = 104 and n = 82), 67.07% compared to 54.9% and 57.32% compared to 54.8%; where the prediction accuracy was determined by the average of the four classifiers. Through Kaplan-Meier analysis on high- and low-risk patients our 12-gene signature revealed statistically significant risk differentiation in each data set: the training set had a p-value less than 0.001 (log-rank) and the two test sets had (log-rank) p-values less than 0.05. Analysis of the posterior probabilities revealed strong correlation between 5-year survival and the 12-gene signature. Also, functional pathway analysis uncovered associations between the 12-gene signature and cancer causing genes in the literature.
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