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Sample records for 2-5 times higher

  1. TWOS - TIME WARP OPERATING SYSTEM, VERSION 2.5.1

    NASA Technical Reports Server (NTRS)

    Bellenot, S. F.

    1994-01-01

    The Time Warp Operating System (TWOS) is a special-purpose operating system designed to support parallel discrete-event simulation. TWOS is a complete implementation of the Time Warp mechanism, a distributed protocol for virtual time synchronization based on process rollback and message annihilation. Version 2.5.1 supports simulations and other computations using both virtual time and dynamic load balancing; it does not support general time-sharing or multi-process jobs using conventional message synchronization and communication. The program utilizes the underlying operating system's resources. TWOS runs a single simulation at a time, executing it concurrently on as many processors of a distributed system as are allocated. The simulation needs only to be decomposed into objects (logical processes) that interact through time-stamped messages. TWOS provides transparent synchronization. The user does not have to add any more special logic to aid in synchronization, nor give any synchronization advice, nor even understand much about how the Time Warp mechanism works. The Time Warp Simulator (TWSIM) subdirectory contains a sequential simulation engine that is interface compatible with TWOS. This means that an application designer and programmer who wish to use TWOS can prototype code on TWSIM on a single processor and/or workstation before having to deal with the complexity of working on a distributed system. TWSIM also provides statistics about the application which may be helpful for determining the correctness of an application and for achieving good performance on TWOS. Version 2.5.1 has an updated interface that is not compatible with 2.0. The program's user manual assists the simulation programmer in the design, coding, and implementation of discrete-event simulations running on TWOS. The manual also includes a practical user's guide to the TWOS application benchmark, Colliding Pucks. TWOS supports simulations written in the C programming language. It is designed

  2. Time Warp Operating System, Version 2.5.1

    NASA Technical Reports Server (NTRS)

    Bellenot, Steven F.; Gieselman, John S.; Hawley, Lawrence R.; Peterson, Judy; Presley, Matthew T.; Reiher, Peter L.; Springer, Paul L.; Tupman, John R.; Wedel, John J., Jr.; Wieland, Frederick P.; Younger, Herbert C.

    1993-01-01

    Time Warp Operating System, TWOS, is special purpose computer program designed to support parallel simulation of discrete events. Complete implementation of Time Warp software mechanism, which implements distributed protocol for virtual synchronization based on rollback of processes and annihilation of messages. Supports simulations and other computations in which both virtual time and dynamic load balancing used. Program utilizes underlying resources of operating system. Written in C programming language.

  3. Monitoring PM2.5 in the Atmosphere by Using Terahertz Time-Domain Spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhan, Honglei; Zhao, Kun; Bao, Rima; Xiao, Lizhi

    2016-09-01

    The real-time monitoring of the air pollution with multiple sources is of great significance for pollution control and environmental protection. In this paper, we presented a study of terahertz time-domain spectroscopy (THz-TDS) as a direct tool for monitoring the component and content of PM2.5 in atmosphere. Due to the THz absorption, the intensities of the peaks in THz-TDS decreased with the augment of PM2.5 and were proportional to the PM2.5 content. The ratio of absorbance A to PM2.5 reflected a basically unchanged tendency, indicating the little change of principal elements under the pollution degree. In the high-pollution condition, a lot of SO2 from vehicle and factory was emitted into air. The elements, such as S and O from anions, had a stronger absorption effect in THz range. Based on the absorbance spectra, the absorption tendencies with PM2.5 over the whole range were validated by principal component analysis and the quantitative model with a high correlation was built by using back propagation artificial neural network. BPANN model improved the precision of linear fitting between peak intensities and PM2.5. The research demonstrates that THz-TDS is a promising tool for fast, direct, and reliable monitoring in environmental applications.

  4. Time Course of Heart Rate Variability Response to PM2.5 Exposure from Secondhand Smoke

    PubMed Central

    Garza, Jennifer L.; Mittleman, Murray A.; Zhang, Jinming; Christiani, David C.; Cavallari, Jennifer M

    2016-01-01

    Purpose: Exposure to secondhand smoke (SHS) has been associated with decreased heart rate variability (HRV). However, the time course of this association is unclear. Therefore, the objective of this study was to investigate the association between 15–240 minute SHS-related fine particulate matter (PM2.5) moving averages and indices of HRV. Methods: With a panel study design, we used personal monitors to continuously measure PM2.5 and HRV of 35 participants who were exposed to SHS for approximately 6 hours. Results: We observed negative, significant associations between 5-minute HRV indices and 15 minute PM2.5 moving averages and 240 minute PM2.5 moving averages: there was a significant (p<0.01) 7.5% decrease in the 5-minute square root of the mean squared differences of successive normal heart beats associated with (RMSSD), and a significant (p<0.01) 14.7% decrease in the 5-minute high frequency (HF) power associated with the 15 minute PM2.5 moving averages; there was also a significant (p<0.01) 46.9% decrease in the 5-minute RMSSD, and a significant (p<0.01) 77.7% decrease in the 5-minute high frequency (HF) power associated with the 240 minute PM2.5 moving averages. Conclusions: Our findings that exposure to SHS related PM2.5 was associated with HRV support the hypothesis that SHS can affect the cardiovascular system. The negative associations reported between short and longer term PM2.5 and HRV indicate adverse effects of SHS on the cardiovascular system. PMID:27223894

  5. Asymmetric multiscale behavior in PM2.5 time series: Based on asymmetric MS-DFA

    NASA Astrophysics Data System (ADS)

    Zhang, Chen; Ni, Zhiwei; Ni, Liping

    2016-11-01

    Particulate matter with an aerodynamic diameter of 2.5 mm or less (PM2.5) is one of the most serious air pollution, considered most harmful for people by World Health Organisation. In this paper, we utilized the asymmetric multiscale detrended fluctuation analysis (A-MSDFA) method to explore the existence of asymmetric correlation properties for PM2.5 daily average concentration in two USA cities (Fresno and Los Angeles) and two Chinese cities (Hong Kong and Shanghai), and to assess the properties of these asymmetric correlations. The results show the existences of asymmetric correlations, and the degree of asymmetric for two USA cities is stronger than that of two Chinese cities. Further, most of the local exponent β(n) are smaller than 0.5, which indicates the existence of anti-persistent long-range correlation for PM2.5 time series in four cities. In addition, we reanalyze the asymmetric correlation by the A-MSDFA method with secant rolling windows of different sizes, which can investigate dynamic changes in the multiscale correlation for PM2.5 time series with changing window size. Whatever window sizes, the correlations are asymmetric and display smaller asymmetries at small scales and larger asymmetries at large scales. Moreover, the asymmetries become increasingly weaker with the increase of window sizes.

  6. Comparing Gravimetric and Real-Time Sampling of PM2.5 Concentrations Inside Truck Cabins

    PubMed Central

    Zhu, Ying; Smith, Thomas J.; Davis, Mary E.; Levy, Jonathan I.; Herrick, Robert; Jiang, Hongyu

    2012-01-01

    As part of a study on truck drivers’ exposure and health risk, pickup and delivery (P&D) truck drivers’ on-road exposure patterns to PM2.5 were assessed in five weeklong sampling trips in metropolitan areas of five U.S. cities from April to August of 2006. Drivers were sampled with real-time (DustTrak) and gravimetric samplers to measure average in-cabin PM2.5 concentrations and to compare their correspondence in moving trucks. In addition, GPS measurements of truck locations, meteorological data, and driver behavioral data were collected throughout the day to determine which factors influence the relationship between real-time and gravimetric samplers. Results indicate that the association between average real-time and gravimetric PM2.5 measurements on moving trucks was fairly consistent (Spearman rank correlation of 0.63), with DustTrak measurements exceeding gravimetric measurements by approximately a factor of 2. This ratio differed significantly only between the industrial Midwest cities and the other three sampled cities scattered in the South and West. There was also limited evidence of an effect of truck age. Filter samples collected concurrently with DustTrak measurements can be used to calibrate average mass concentration responses for the DustTrak, allowing for real-time measurements to be integrated into longer-term studies of inter-city and intra-urban exposure patterns for truck drivers. PMID:21991940

  7. Comparing gravimetric and real-time sampling of PM(2.5) concentrations inside truck cabins.

    PubMed

    Zhu, Ying; Smith, Thomas J; Davis, Mary E; Levy, Jonathan I; Herrick, Robert; Jiang, Hongyu

    2011-11-01

    As part of a study on truck drivers' exposure and health risk, pickup and delivery (P&D) truck drivers' on-road exposure patterns to PM(2.5) were assessed in five, weeklong sampling trips in metropolitan areas of five U.S. cities from April to August of 2006. Drivers were sampled with real-time (DustTrak) and gravimetric samplers to measure average in-cabin PM(2.5) concentrations and to compare their correspondence in moving trucks. In addition, GPS measurements of truck locations, meteorological data, and driver behavioral data were collected throughout the day to determine which factors influence the relationship between real-time and gravimetric samplers. Results indicate that the association between average real-time and gravimetric PM(2.5) measurements on moving trucks was fairly consistent (Spearman rank correlation of 0.63), with DustTrak measurements exceeding gravimetric measurements by approximately a factor of 2. This ratio differed significantly only between the industrial Midwest cities and the other three sampled cities scattered in the South and West. There was also limited evidence of an effect of truck age. Filter samples collected concurrently with DustTrak measurements can be used to calibrate average mass concentration responses for the DustTrak, allowing for real-time measurements to be integrated into longer-term studies of inter-city and intra-urban exposure patterns for truck drivers.

  8. Asymmetric multifractal detrending moving average analysis in time series of PM2.5 concentration

    NASA Astrophysics Data System (ADS)

    Zhang, Chen; Ni, Zhiwei; Ni, Liping; Li, Jingming; Zhou, Longfei

    2016-09-01

    In this paper, we propose the asymmetric multifractal detrending moving average analysis (A-MFDMA) method to explore the asymmetric correlation in non-stationary time series. The proposed method is applied to explore the asymmetric correlation of PM2.5 daily average concentration with uptrends or downtrends in China. In addition, shuffling and phase randomization procedures are applied to detect the sources of multifractality. The results show that existences of asymmetric correlations, and the asymmetric correlations are multifractal. Further, the multifractal scaling behavior in the Chinese PM2.5 is caused not only by long-range correlation but also by fat-tailed distribution, but the major source of multifractality is fat-tailed distribution.

  9. Higher Education for Our Time

    ERIC Educational Resources Information Center

    Burnett, Dana D.; Collins, Natalia D.

    2010-01-01

    Public higher education is currently experiencing a decline in financial support from state governments, an acceleration of enrollment growth, and a shift from a transformational to a transactional student relationship. Private institutions are also struggling with increasing operational costs, and decreases in revenue from endowments and…

  10. Part Time Study in Higher Education.

    ERIC Educational Resources Information Center

    Neville, Colin

    This document, which is intended for adults considering enrolling in part-time study in higher education, examines the objectives and experiences of adults who have pursued part-time study in higher education in the United Kingdom. The following reasons why adults return to higher education are discussed: personal development; self-fulfillment;…

  11. Sleep Disorders 6 Times Higher Among Veterans

    MedlinePlus

    ... page: https://medlineplus.gov/news/fullstory_159985.html Sleep Disorders 6 Times Higher Among Veterans Post-traumatic ... 20, 2016 WEDNESDAY, July 20, 2016 (HealthDay News) -- Sleep disorders are six times more likely among American ...

  12. Real-time particle monitor calibration factors and PM2.5 emission factors for multiple indoor sources.

    PubMed

    Dacunto, Philip J; Cheng, Kai-Chung; Acevedo-Bolton, Viviana; Jiang, Ruo-Ting; Klepeis, Neil E; Repace, James L; Ott, Wayne R; Hildemann, Lynn M

    2013-08-01

    Indoor sources can greatly contribute to personal exposure to particulate matter less than 2.5 μm in diameter (PM2.5). To accurately assess PM2.5 mass emission factors and concentrations, real-time particle monitors must be calibrated for individual sources. Sixty-six experiments were conducted with a common, real-time laser photometer (TSI SidePak™ Model AM510 Personal Aerosol Monitor) and a filter-based PM2.5 gravimetric sampler to quantify the monitor calibration factors (CFs), and to estimate emission factors for common indoor sources including cigarettes, incense, cooking, candles, and fireplaces. Calibration factors for these indoor sources were all significantly less than the factory-set CF of 1.0, ranging from 0.32 (cigarette smoke) to 0.70 (hamburger). Stick incense had a CF of 0.35, while fireplace emissions ranged from 0.44-0.47. Cooking source CFs ranged from 0.41 (fried bacon) to 0.65-0.70 (fried pork chops, salmon, and hamburger). The CFs of combined sources (e.g., cooking and cigarette emissions mixed) were linear combinations of the CFs of the component sources. The highest PM2.5 emission factors per time period were from burned foods and fireplaces (15-16 mg min(-1)), and the lowest from cooking foods such as pizza and ground beef (0.1-0.2 mg min(-1)). PMID:23784066

  13. Refined Assessment of Human PM2.5 Exposure in Chinese city by Incorporating Time-activity Data

    NASA Astrophysics Data System (ADS)

    Zhu, W.; Wang, H.

    2015-12-01

    Since urban residents tend to spend a majority of time indoors throughout a day, it has been widely discussed in recent years, whether fixed-site monitoring PM2.5 ambient concentration is feasible as a surrogate of human PM2.5 exposure. Comprehensive understanding of residents' daily time-activity patterns (TAP) and possible indoor behavior are urgently needed to perform a more accurate estimate of human PM2.5exposure, especially in China, where is experiencing rapid urbanization.Field surveys of TAP were carried out in a Chinese city of Suzhou from 2014 to 2015 to evaluate PM2.5 exposure in various micro-environments (ME, e.g., residence, outdoors and in-transit). We gathered and analyzed urban residents' seasonal time-activity data using 24h retrospective time-location diaries, as well as diversified exposure-related indoor information (e.g. ventilation, environment tobacco smoke and cooking). PM2.5exposure is calculated through the incorporation of ambient concentration data, modified indoor/outdoor empirical functions and TAP. The spatial distributions of TAP-based exposure and static-population based exposure are also compared.Residents in Suzhou urban area spend over 65% of time at home and 90% indoors. There are significant temporal (season, day type) and socioeconomic differences (gender, age, education, living alone, having children at home, employment status, etc.) of time-activity distributions, which makes the sum of PM2.5 ME exposure differs notably from static-population based ambient exposure. People prefer to spend more time at home both in winter (P<0.05) and on weekends (P<0.001), less time outdoors in winter but more on weekends (P<0.001). Gender, education and living alone are negative associated with time spent home, while age, children at home and employment status are positively related. On the other hand, due to lack of monitoring stations in unban Suzhou, the inverse distance squared weighting method is not ideally performed and may be less

  14. Source Identification of PM2.5 in Steubenville, Ohio Using a Hybrid Method for Highly Time-resolved Data

    EPA Science Inventory

    A new source-type identification method, Reduction and Species Clustering Using Episodes (ReSCUE), was developed to exploit the temporal synchronicity between species to form clusters of species that vary together. High time-resolution (30 min) PM2.5 sampling was condu...

  15. PM2.5 Characterization for Time Series Studies: Pointwise Uncertainty Estimation and Bulk Speciation Methods Applied in Denver

    PubMed Central

    Dutton, Steven J.; Schauer, James J.; Vedal, Sverre; Hannigan, Michael P.

    2009-01-01

    Many studies have identified associations between adverse health effects and short-term exposure to particulate matter less than 2.5 microns in diameter (PM2.5). These effects, however, are not consistent across geographical regions. This may be due in part to variations in the chemical make-up of PM2.5 resulting from unique combinations of sources, both primary and secondary, in different regions. The Denver Aerosol Sources and Health (DASH) study is a multi-year time series study designed to characterize the daily chemical composition of PM2.5 in Denver, identify the major contributing sources, and investigate associations between sources and a broad array of adverse health outcomes. Measurement methodology, field blank correction, pointwise uncertainty estimation and detection limit consideration are discussed in the context of bulk speciation for the DASH study. Results are presented for the first 4.5 years of mass, inorganic ion and bulk carbon speciation. The derived measurement uncertainties were propagated using the root sum of squares method and show good agreement with precision estimates derived from bi-weekly duplicate samples collected on collocated samplers. Gravimetric mass has the most uncertainty of any measurement and reconstructed mass generated from the sum of the individual species shows less uncertainty than measured mass on average. The methods discussed provide a good framework for PM2.5 speciation measurements and are generalizable to analysis of other environmental measures. PMID:20126292

  16. Victims' Time Discounting 2.5 Years after the Wenchuan Earthquake: An ERP Study

    PubMed Central

    Feng, Chun-Liang; Wang, Wen-Zhong; Du, Bo-Qi; Gan, Tian; Luo, Yue-Jia

    2012-01-01

    Background Time discounting refers to the fact that the subjective value of a reward decreases as the delay until its occurrence increases. The present study investigated how time discounting has been affected in survivors of the magnitude-8.0 Wenchuan earthquake that occurred in China in 2008. Methodology Nineteen earthquake survivors and 22 controls, all school teachers, participated in the study. Event-related brain potentials (ERPs) for time discounting tasks involving gains and losses were acquired in both the victims and controls. Findings The behavioral data replicated our previous findings that delayed gains were discounted more steeply after a disaster. ERP results revealed that the P200 and P300 amplitudes were increased in earthquake survivors. There was a significant group (earthquake vs. non- earthquake) × task (gain vs. loss) interaction for the N300 amplitude, with a marginally significantly reduced N300 for gain tasks in the experimental group, which may suggest a deficiency in inhibitory control for gains among victims. Conclusions The results suggest that post-disaster decisions might involve more emotional (System 1) and less rational thinking (System 2) in terms of a dual-process model of decision making. The implications for post-disaster intervention and management are also discussed. PMID:22792277

  17. Time-resolved measurements of PM2.5 carbonaceous aerosols at Gosan, Korea.

    PubMed

    Batmunkh, T; Kim, Y J; Lee, K Y; Cayetano, M G; Jung, J S; Kim, S Y; Kim, K C; Lee, S J; Kim, J S; Chang, L S; An, J Y

    2011-11-01

    In order to better understand the characteristics of atmospheric carbonaceous aerosol at a background site in Northeast Asia, semicontinuous organic carbon (OC) and elemental carbon (EC), and time-resolved water-soluble organic carbon (WSOC) were measured by a Sunset OC/ EC and a PILS-TOC (particle-into-liquid sampler coupled with an online total organic carbon) analyzer, respectively, at the Gosan supersite on Jeju Island, Korea, in the summer (May 28-June 17) and fall (August 24-September 30) of 2009. Hourly average OC concentration varied in the range of approximately 0.87-28.38 microgC m-3, with a mean of 4.07+/- 2.60 microgC m-3, while the hourly average EC concentration ranged approximately from 0.04 to 8.19 .microgC m-3, with a mean of 1.35 +/- 0.71 microgC m-3, from May 28 to June 17, 2009. During the fall season, OC varied in the approximate range 0.9-9.6 microgC m-3, with a mean of 2.30 +/-0.80 microgC m-3, whereas EC ranged approximately from 0.01 to 5.40 microgC m-3, with a mean of 0.66 +/- 0.38 microgC m-3. Average contributions of EC to TC and WSOC to OC were 26.0% +/- 9.7% and 20.6% +/-7.4%, and 37.6% +/- 23.5% and 57.2% +/- 22.2% during summer and fall seasons, respectively. As expected, clear diurnal variation of WSOC/OC was found in summer, varying from 0.22 during the nighttime up to 0.72 during the daytime, mainly due to the photo-oxidation process. In order to investigate the effect of air mass pathway on the characteristics of carbonaceous aerosol, 5-day back-trajectory analysis was conducted using the HYSPLIT model. The air mass pathways were classified into four types: Continental (CC), Marine (M), East Sea (ES) and Korean Peninsula (KP). The highest OC/EC ratio of 3.63 was observed when air mass originated from the Continental area (CC). The lowest OC/EC ratio of 0.79 was measured when air mass originated from the Marine area (M). A high OC concentration was occasionally observed at Gosan due to local biomass burning activities. The

  18. Measurement, time series analysis and source apportionment of inorganic and organic speciated PM(2.5) air pollution in Denver

    NASA Astrophysics Data System (ADS)

    Dutton, Steven James

    Particulate air pollution has demonstrated significant health effects ranging from worsening of asthma to increased rates of respiratory and cardiopulmonary mortality. These results have prompted the US-EPA to include particulate matter (PM) as one of the six criteria air pollutants regulated under the Clean Air Act. The diverse chemical make-up and physical characteristics of PM make it a challenging pollutant to characterize and regulate. Particulate matter less than 2.5 microns in diameter (PM2.5) has the ability to travel deep into the lungs and therefore has been linked with some of the more significant health effects. The toxicity of any given particle is likely dependent on its chemical composition. The goal of this project has been to chemically characterize a long time series of PM 2.5 measurements collected at a receptor site in Denver to a level of detail that has not been done before on this size data set. This has involved characterization of inorganic ions using ion chromatography, total elemental and organic carbon using thermal optical transmission, and organic molecular marker species using gas chromatography-mass spectrometry. Methods have been developed to allow for daily measurement and speciation for these compounds over a six year period. Measurement methods, novel approaches to uncertainty estimation, time series analysis, spectral and pattern analyses and source apportionment using two multivariate factor analysis models are presented. Analysis results reveal several natural and anthropogenic sources contributing to PM2.5 in Denver. The most distinguishable sources are motor vehicles and biomass combustion. This information will be used in a health effect analysis as part of a larger study called the Denver Aerosol Sources and Health (DASH) study. Such results will inform regulatory decisions and may help create a better understanding of the underlying mechanisms for the observed adverse health effects associated with PM2.5.

  19. Source identification of PM2.5 in Steubenville, Ohio using a hybrid method for highly time-resolved data.

    PubMed

    Vedantham, Ram; Landis, Matthew S; Olson, David; Pancras, Joseph Patrick

    2014-01-01

    A new source-type identification method, Reduction and Species Clustering Using Episodes (ReSCUE), was developed to exploit the temporal synchronicity typically observed between ambient species in high time resolution fine particulate matter (PM2.5) data to form clusters that vary together. High time-resolution (30 min) PM2.5 sampling was conducted for a month during the summer of 2006 in Steubenville, OH, an EPA designated nonattainment area for the U.S. National Ambient Air Quality Standards (NAAQS). When the data were evaluated, the species clusters from ReSCUE matched extremely well with the source types identified by EPA Unmix demonstrating that ReSCUE is a valuable tool in identifying source types. Results from EPA Unmix show that contributions to PM2.5 are mostly from iron/steel manufacturing (36% ± 9%), crustal matter (33% ± 11%), and coal combustion (11% ± 19%). More importantly, ReSCUE was useful in (i) providing objective data driven guidance for the number of source factors and key fitting species for EPA Unmix, and (ii) detecting tenuous associations between some species and source types in the results derived by EPA Unmix.

  20. Impacts of Stabilized Criegee Intermediates, surface uptake processes and higher aromatic secondary organic aerosol yields on predicted PM2.5 concentrations in the Mexico City Metropolitan Zone

    NASA Astrophysics Data System (ADS)

    Ying, Qi; Cureño, Iris V.; Chen, Gang; Ali, Sajjad; Zhang, Hongliang; Malloy, Meagan; Bravo, Humberto A.; Sosa, Rodolfo

    2014-09-01

    The Community Multiscale Air Quality Model (CMAQ) with the SAPRC-99 gas phase photochemical mechanism and the AERO5 aerosol module was applied to model gases and particulate matter (PM) concentrations in the Mexico City Metropolitan Zone (MCMZ) and the surrounding regions for March 2006 using the official 2006 emission inventories, along with emissions from biogenic sources, biomass burning, windblown dust, the Tula Industrial Complex and the Popocatépetl volcano. The base case model was capable of reproducing the observed hourly concentrations of O3 and attaining CO, NO2 and NOx performance similar to previous modeling studies. Although the base case model performance of hourly PM2.5 and PM10 meets the model performance criteria, under-prediction of high PM2.5 concentrations in late morning indicates that secondary PM, such as sulfate and secondary organic aerosol (SOA), might be under-predicted. Several potential pathways to increase SOA and secondary sulfate were investigated, including Stabilized Criegee Intermediates (SCIs) from ozonolysis reactions of unsaturated hydrocarbons and their reactions with SO2, the reactive uptake processes of SO2, glyoxal and methylglyoxal on particle surface and higher SOA formation due to higher mass yields of aromatic SOA precursors. Averaging over the entire episode, the glyoxal and methylglyoxal reactive uptake and higher aromatics SOA yields contribute to ∼0.9 μg m-3 and ∼1.25 μg m-3 of SOA, respectively. Episode average SOA in the MCMZ reaches ∼3 μg m-3. The SCI pathway increases PM2.5 sulfate by 0.2-0.4 μg m-3 or approximately 10-15%. The relative amount of sulfate increase due to SCI agrees with previous studies in summer eastern US. Surface SO2 uptake significantly increases sulfate concentration in MCMZ by 1-3 μg m-3 or approximately 50-60%. The higher SOA and sulfate leads to improved PM2.5 and PM10 model performance.

  1. A CROSS-PROVINCE ANALYSIS OF URBAN AND RURAL INDOOR PM2.5 EXPOSURE IN CHINA USING TIME USE SURVEY

    NASA Astrophysics Data System (ADS)

    Shimada, Yoko; Guo, Minna; Kurata, Gakuji; Matsuoka, Yuzuru

    In developing countries in Asia and other parts of the world, most energy sources used in the home are solid fuels such as coal and biomass (firewood, crop residue and animal dung). Particulate matter 2.5, consisting of particles with an aerodynamic diameter of 2.5 um or less, produced through combustion of these fuels inside the residence for cooking and heating has an adverse impact on people's health. We estimated PM2.5 exposure concentration in indoor microenvironment for each cohort of urban and rural area in ten provinces of China, using statistical data on time use survey and domestic energy consumption. The study found that, in each province, the exposure concentration in rural area was higher than in urban area, unemployed women between the ages of 60 and 64 had the highest estimate for exposure concentration at 3027 μg/m3. The study also found that the exposure concentration for individual cohorts in each province was greatly affected by people's use of time indoors, fuel consumption such as coal or biomass and floor space.

  2. Strategies for Hard Times in Higher Education.

    ERIC Educational Resources Information Center

    Desfosses, Louis R.

    1996-01-01

    Planning and management strategies used in the private sector have practical applications for higher education in a period of systemic and organizational stress. Promising strategies include organizational delayering; employee empowerment; boundless thinking, problem-solving teams; accelerated processes; quality management and improvement; and…

  3. Higher Education: A Time for Triage?

    NASA Astrophysics Data System (ADS)

    Lagowski, J. J.

    1995-10-01

    Higher education faces unprecedented challenges. The confluence of changing economic and demographic tends; new patterns of federal and state spending; more explicit expectations by students and their families for affordable, accessible education; and heightened scrutiny by those who claim a legitimate interest in higher education is inescapably altering the environment in which this system operates. Higher education will never again be as it was before. Further, many believe that tinkering around the margins is no longer an adequate response to the new demands. Fundamental change is deemed necessary to meet the challenge of this melange of pressures. A number of commentators have observed that political and corporate America have responded to their challenges by instituting a fundamental restructuring of those institutions. The medical community is also in the midst of a similar basic restructuring of the health care delivery system in this country. Now its education's turn. People are questioning the historically expressed mission of higher education. They make the claim that we cost too much, spend carelessly, teach poorly, plan myopically, and when questioned, act defensively. Educational administrators, from department chairs up, are confronted with the task of simultaneously reforming and cutting back. They have no choice. They must establish politically sophisticated priority settings and effect a hard-nosed reallocation of resources in a social environment where competing public needs have equivalent--or stronger--emotional pulls. Triage in a medical context involves confronting an emergency in which the demand for attention far outstrips available assistance by establishing a sequence of care in which one key individual orchestrates the application of harsh priorities which have been designed to maximize the number of survivors. In recent years, the decisions that have been made in some centers of higher education bear a striking similarity. The literature

  4. Higher Education: A Time for Triage?

    NASA Astrophysics Data System (ADS)

    Lagowski, J. J.

    1995-10-01

    Higher education faces unprecedented challenges. The confluence of changing economic and demographic tends; new patterns of federal and state spending; more explicit expectations by students and their families for affordable, accessible education; and heightened scrutiny by those who claim a legitimate interest in higher education is inescapably altering the environment in which this system operates. Higher education will never again be as it was before. Further, many believe that tinkering around the margins is no longer an adequate response to the new demands. Fundamental change is deemed necessary to meet the challenge of this melange of pressures. A number of commentators have observed that political and corporate America have responded to their challenges by instituting a fundamental restructuring of those institutions. The medical community is also in the midst of a similar basic restructuring of the health care delivery system in this country. Now its education's turn. People are questioning the historically expressed mission of higher education. They make the claim that we cost too much, spend carelessly, teach poorly, plan myopically, and when questioned, act defensively. Educational administrators, from department chairs up, are confronted with the task of simultaneously reforming and cutting back. They have no choice. They must establish politically sophisticated priority settings and effect a hard-nosed reallocation of resources in a social environment where competing public needs have equivalent--or stronger--emotional pulls. Triage in a medical context involves confronting an emergency in which the demand for attention far outstrips available assistance by establishing a sequence of care in which one key individual orchestrates the application of harsh priorities which have been designed to maximize the number of survivors. In recent years, the decisions that have been made in some centers of higher education bear a striking similarity. The literature

  5. Resonance Raman study of the A-band short-time photodissociation dynamics of 2,5-di-iodothiophene

    SciTech Connect

    Ruan Caibin; Zhu Hailin; Wang Huigang; Zheng Xuming; Phillips, David Lee

    2008-12-07

    Resonance Raman spectra were obtained for 2,5-di-iodothiophene in cyclohexane solution with excitation wavelengths in resonance with its A-band absorption. These spectra indicate that the Franck-Condon region photodissociation dynamics have multidimensional character with motion mostly along the nominal symmetric C{sub 2}C{sub 3}/C{sub 4}C{sub 5} stretch {nu}{sub 2} (1388 cm{sup -1}) of the thienyl ring and this is accompanied by motions along the nominal symmetric CSC stretch {nu}{sub 6} (640 cm{sup -1}), the nominal symmetric C-I stretch {nu}{sub 7} (187 cm{sup -1}), the nominal antisymmetric CSC stretch {nu}{sub 19} (728 cm{sup -1}), the nominal antisymmetric C{sub 2}C{sub 3}/C{sub 4}C{sub 5} stretch {nu}{sub 16} (1497 cm{sup -1}), the nominal C{sub 3}C{sub 4} stretch {nu}{sub 3} (1286 cm{sup -1}) and four other vibrational modes. A preliminary resonance Raman intensity analysis was done and the results for 2,5-di-iodothiophene were compared to previous results for 2-iodothiophene and di-iodomethane to discuss the mechanism of the symmetric breaking in the initial A-band photodissociation dynamics of 2,5-di-iodothiophene and 2-iodothiophene.

  6. Real-Time Estimation of Satellite-Derived PM2.5 Based on a Semi-Physical Geographically Weighted Regression Model

    PubMed Central

    Zhang, Tianhao; Liu, Gang; Zhu, Zhongmin; Gong, Wei; Ji, Yuxi; Huang, Yusi

    2016-01-01

    The real-time estimation of ambient particulate matter with diameter no greater than 2.5 μm (PM2.5) is currently quite limited in China. A semi-physical geographically weighted regression (GWR) model was adopted to estimate PM2.5 mass concentrations at national scale using the Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Aerosol Optical Depth product fused by the Dark Target (DT) and Deep Blue (DB) algorithms, combined with meteorological parameters. The fitting results could explain over 80% of the variability in the corresponding PM2.5 mass concentrations, and the estimation tends to overestimate when measurement is low and tends to underestimate when measurement is high. Based on World Health Organization standards, results indicate that most regions in China suffered severe PM2.5 pollution during winter. Seasonal average mass concentrations of PM2.5 predicted by the model indicate that residential regions, namely Jing-Jin-Ji Region and Central China, were faced with challenge from fine particles. Moreover, estimation deviation caused primarily by the spatially uneven distribution of monitoring sites and the changes of elevation in a relatively small region has been discussed. In summary, real-time PM2.5 was estimated effectively by the satellite-based semi-physical GWR model, and the results could provide reasonable references for assessing health impacts and offer guidance on air quality management in China. PMID:27706054

  7. Characteristics and sensitivity analysis of multiple-time-resolved source patterns of PM2.5 with real time data using Multilinear Engine 2

    NASA Astrophysics Data System (ADS)

    Peng, Xing; Shi, Guo-Liang; Gao, Jian; Liu, Jia-Yuan; HuangFu, Yan-Qi; Ma, Tong; Wang, Hai-Ting; Zhang, Yue-Chong; Wang, Han; Li, Hui; Ivey, Cesunica E.; Feng, Yin-Chang

    2016-08-01

    With real time resolved data of Particulate matter (PM) and chemical species, understanding the source patterns and chemical characteristics is critical to establish controlling of PM. In this work, PM2.5 and chemical species were measured by corresponding online instruments with 1-h time resolution in Beijing. Multilinear Engine 2 (ME2) model was applied to explore the sources, and four sources (vehicle emission, crustal dust, secondary formation and coal combustion) were identified. To investigate the sensitivity of time resolution on the source contributions and chemical characteristics, ME2 was conducted with four time resolution runs (1-h, 2-h, 4-h, and 8-h). Crustal dust and coal combustion display large variation in the four time resolutions runs, with their contributions ranging from 6.7 to 10.4 μg m-3 and from 6.4 to 12.2 μg m-3, respectively. The contributions of vehicle emission and secondary formation range from 7.5 to 10.5 and from 14.7 to 16.7 μg m-3, respectively. The sensitivity analyses were conducted by principal component analysis-plot (PCA-plot), coefficient of divergence (CD), average absolute error (AAE) and correlation coefficients. For the four time resolution runs, the source contributions and profiles of crustal dust and coal combustion were more unstable than other source categories, possibly due to the lack of key markers of crustal dust and coal combustion (e.g. Si, Al). On the other hand, vehicle emission and crustal dust were more sensitive to time series of source contributions at different time resolutions. Findings in this study can improve our knowledge of source contributions and chemical characteristics at different time solutions.

  8. Air quality forecasting for winter-time PM2.5 episodes occurring in multiple cities in central and southern Chile

    NASA Astrophysics Data System (ADS)

    Saide, Pablo E.; Mena-Carrasco, Marcelo; Tolvett, Sebastian; Hernandez, Pablo; Carmichael, Gregory R.

    2016-01-01

    Episodic air quality degradation due to particles occurs in multiple cities in central and southern Chile during the austral winter reaching levels up to 300-800 µg/m3 hourly PM2.5, which can be associated with severe effects on human health. An air quality prediction system is developed to predict such events in near real time up to 3 days in advance for nine cities with regular air quality monitoring: Santiago, Rancagua, Curicó, Talca, Chillan, Los Ángeles, Temuco, Valdivia, and Osorno. The system uses the Weather Research and Forecasting with Chemistry model configured with a nested 2 km grid-spacing domain to predict weather and inert tracers. The tracers are converted to hourly PM2.5 concentrations using an observationally based calibration which is substantially less computationally intensive than a full chemistry model. The conversion takes into account processes occurring in these cities, including higher likelihood of episode occurrence during weekends and during colder days, the latter related to increased wood-burning-stove activity for heating. The system is calibrated and evaluated for April-August 2014 where it has an overall skill of 53-72% of episodes accurately forecasted (61-76% for the best initialization) which is better than persistence for most stations. Forecasts one, two, and three days in advance all have skill in forecasting events but often present large variability within them due to different meteorological initializations. The system is being implemented in Chile to assist authority decisions not only to warn the population but also to take contingency-based emission restrictions to try to avoid severe pollution events.

  9. Representing 30 Years of Higher Education Change: UK Universities and the "Times Higher"

    ERIC Educational Resources Information Center

    Gewirtz, Sharon; Cribb, Alan

    2013-01-01

    This paper argues that the "Times Higher" provides a powerful tool for understanding the changing character of UK higher education (HE) and can usefully be seen as representative, and in some ways constitutive, of that changing character. Drawing on an analysis of a sample of stories from the "Times Higher," it documents the changing policy…

  10. Representing 30 Years of Higher Education Change: UK Universities and the "Times Higher"

    ERIC Educational Resources Information Center

    Gewirtz, Sharon; Cribb, Alan

    2013-01-01

    This paper argues that the "Times Higher" provides a powerful tool for understanding the changing character of UK higher education (HE) and can usefully be seen as representative, and in some ways constitutive, of that changing character. Drawing on an analysis of a sample of stories from the "Times Higher," it documents the…

  11. FIELD EVALUATION OF A MODIFIED DATARAM MIE SCATTERING MONITOR FOR REAL-TIME PM2.5 MASS CONCENTRATION MEASUREMENTS. (R827352C005)

    EPA Science Inventory

    In this paper, we investigated the feasibility of using a modified DataRAM nephelometer (RAM-1, MIE Inc., Billerica, MA) as a continuous PM2.5 monitor to measure concentrations of ambient and concentrated aerosols in real time. The DataRAM operated with a diffusion ...

  12. Source identification of ambient PM 2.5 for inhalation exposure studies in Steubenville, Ohio using highly time-resolved measurements

    NASA Astrophysics Data System (ADS)

    Morishita, Masako; Keeler, Gerald J.; Kamal, Ali S.; Wagner, James G.; Harkema, Jack R.; Rohr, Annette C.

    2011-12-01

    Recent epidemiological and toxicological studies have suggested that short-term elevations of ambient fine particle mass concentrations (aerodynamic diameter <2.5 μm, PM 2.5) can increase cardiac and pulmonary health risks. Thus, examining temporal variations of chemical changes in ambient PM 2.5 that could pose the greatest health risks and identifying its sources is critical so that the most toxic categories can be controlled. In this study we collected detailed air quality data in Steubenville, Ohio in August 2006 with the ultimate goal to evaluate associations between cardiovascular (CV) parameters measured in exposed laboratory animals and the chemical and elemental composition of PM 2.5. Current approaches using radiotelemetry to measure CV parameters in conscious laboratory animals are capable of collecting continuous recordings. To provide a robust and analogous dataset that can be better matched with CV responses, we have incorporated a highly time-resolved sampling method to characterize trace elements and thereby obtain more robust input data to determine potential emission sources. We applied positive matrix factorization (PMF) to trace element concentrations from 30-minute ambient PM 2.5 samples in Steubenville, Ohio, an area designated as a non-attainment area for the PM 2.5 National Ambient Air Quality Standards by the Environmental Protection Agency. The average ambient PM 2.5 filter-based mass concentration during the 8-hour summer exposure study period was 26 ± 11 μg m -3. Results from PMF indicated that six major factors contributed to the ambient PM 2.5 mass during this time: coal combustion/secondary (39 ± 46%), mobile sources (12 ± 14%), metal coating/processing (10 ± 11%), iron and steel manufacturing (5 ± 5%), Pb factor (5 ± 8%), and incineration/smelting (1 ± 3%). The objectives of this paper are (1) to present chemical composition of ambient PM 2.5 and its potential emission sources in Steubenville; and (2) to evaluate the PMF

  13. Just in Time Research: Data Breaches in Higher Education

    ERIC Educational Resources Information Center

    Grama, Joanna

    2014-01-01

    This "Just in Time" research is in response to recent discussions on the EDUCAUSE Higher Education Information Security Council (HEISC) discussion list about data breaches in higher education. Using data from the Privacy Rights Clearinghouse, this research analyzes data breaches attributed to higher education. The results from this…

  14. Identification of ambient PM 2.5 sources and analysis of pollution episodes in Detroit, Michigan using highly time-resolved measurements

    NASA Astrophysics Data System (ADS)

    Morishita, Masako; Keeler, Gerald J.; Kamal, Ali S.; Wagner, James G.; Harkema, Jack R.; Rohr, Annette C.

    2011-03-01

    Recent studies have indicated that the chemical composition of ambient PM 2.5, or fine particulate matter (aerodynamic diameter <2.5 μm), may be closely associated with the health effects induced by PM. Thus, identification of the sources of these components of PM 2.5 is critical to understanding source-specific health risks posed by PM 2.5. However, ambient PM measurements are typically 24-h average concentrations, masking the temporal variability of individual sources. These daily samples can limit our understanding of the associations between sources and observed heath effect parameters. In the present study, highly time-resolved sampling methods were utilized to characterize trace element concentrations and to obtain information on potential emission sources impacting a site in urban Detroit where a complex mixture of local point and mobile sources, as well as regional sources, is observed. Positive matrix factorization (PMF) was applied to 117 8-h PM 2.5 filter samples from which six major factors were extracted including secondary aerosol, gasoline-powered vehicles, iron and steel manufacturing, diesel-powered vehicles, refining, and sludge incineration. In addition, PMF was applied to 268 30-min PM 2.5 samples where six major source factors were identified including secondary aerosol, gasoline- and diesel-powered vehicles, iron and steel manufacturing, refining, sludge incineration, and cement/lime production. Contributions of various emission source factors and peak concentrations for each factor were characterized using detailed meteorology and, factor directionality analysis. Although some variations were observed between the 8-h integrated filter samples and the 30-min SEAS samples, the results from the two datasets are generally consistent, suggesting that 46% and 43% of ambient PM, respectively, is derived from local sources. These findings have advanced our understanding of temporal PM source-receptor relationships in a complex urban air shed.

  15. Implementing constrained multi-time approach with bootstrap analysis in ME-2: An application to PM2.5 data from Florence (Italy).

    PubMed

    Crespi, A; Bernardoni, V; Calzolai, G; Lucarelli, F; Nava, S; Valli, G; Vecchi, R

    2016-01-15

    Advanced receptor models have been recently developed and tested in order to improve the resolution of apportionment problems reducing rotational ambiguity of results and aiming at identifying a larger number of sources. In particular, multi-time model is a factor analysis method able to compute source profiles and contributions using aerosol compositional data with different time resolutions. Unlike traditional factor analysis, each measured value can be inserted into multi-time model with its original time schedule, thus all temporal information can be effectively used in the modelling process. In this work, multi-time model was expanded in order to impose constraints on modelled factors aiming at improving the source identification. Moreover, as far as we know for the first time, a suitable bootstrap technique was implemented in the multi-time scheme to estimate the uncertainty of the final constrained solutions. These implemented approaches were tested on a PM2.5 (particulate matter with aerodynamic diameter <2.5 μm) dataset composed of 24-h samples collected during one year and hourly data sampled in parallel for two shorter periods in Florence (Italy). The daily samples were chemically characterised for elements, ions and carbonaceous components while elemental concentrations only were available for high-time resolved samples. The application of the advanced model revealed the major contribution from traffic (accounting for 37% of PM2.5 as annual average) and allowed an accurate characterisation of involved emission processes. In particular, exhaust and non-exhaust emissions were identified. The constraints imposed in the continuation run led to a better description of the factor associated to nitrates and also of biomass burning profile and the bootstrap results gave useful information to assess the reliability of source apportionment solutions. Finally, the comparison with the results computed by ME-2 base model applied to daily and hourly compositional

  16. Air pollution and early deaths in the United States. Part II: Attribution of PM2.5 exposure to emissions species, time, location and sector

    NASA Astrophysics Data System (ADS)

    Dedoussi, Irene C.; Barrett, Steven R. H.

    2014-12-01

    Combustion emissions constitute the largest source of anthropogenic emissions in the US, and lead to the degradation of air quality and human health. In Part I we computed the population fine particulate matter (PM2.5) exposure and number of early deaths caused by emissions from six major sectors: electric power generation, industry, commercial and residential activities, road transportation, marine transportation and rail transportation. In Part II we attribute exposure and early deaths to sectors, emissions species, time of emission, and location of emission. We apply a long-term adjoint sensitivity analysis and calculate the four dimensional sensitivities (time and space) of PM2.5 exposure with respect to each emissions species. Epidemiological evidence is used to relate increased population exposure to premature mortalities. This is the first regional application of the adjoint sensitivity analysis method to characterize long-term air pollution exposure. (A global scale application has been undertaken related to intercontinental pollution.) We find that for the electric power generation sector 75% of the attributable PM2.5 exposure is due to SO2 emissions, and 80% of the annual impacts are attributed to emissions from April to September. In the road transportation sector, 29% of PM2.5 exposure is due to NOx emissions and 33% is from ammonia (NH3), which is a result of emissions after-treatment technologies. We estimate that the benefit of reducing NH3 emissions from road transportation is ∼20 times that of NOx per unit mass. 75% of the road transportation ammonia impacts occur during the months October to March. We publicly release the sensitivity matrices computed, noting their potential use as a rapid air quality policy assessment tool.

  17. The Times Higher Education Ranking Product: Visualising Excellence through Media

    ERIC Educational Resources Information Center

    Stack, Michelle L.

    2013-01-01

    This paper will examine the Times Higher Education's (THE) World University Rankings as a corporate media product. A number of empirical studies have critiqued the methodology of the THE, yet individuals, Higher Education Institutions (HEIs) and governments continue to use them for decision-making. This paper analyses the influence of…

  18. Higher Education in Recessionary Times: A UK Colloquium

    ERIC Educational Resources Information Center

    Evans, Mary

    2010-01-01

    This article talks about a meeting on "Higher Education in Recessionary Times" on March 24, 2010, which was hosted by the Society for Higher Education Research Policy Network. Although the meeting did take place in the context of an expected General Election, and on budget day, there was a general sense on the day that whoever won the Election (or…

  19. Adopting Consumer Time: Potential Issues for Higher Education

    ERIC Educational Resources Information Center

    Gibbs, Paul

    2009-01-01

    Time and temporality have received little attention in the consumerism, marketing or, until recently, higher education literature. This paper attempts to compare the notions of timing implicit in education as "paideia" (transitional personal growth) with that implicit in consumerism and the marketing practices which foster it. This investigation…

  20. Optical absorption spectra of boron clusters Bn (n = 2-5) for application in nano scintillator - a time dependent density functional theory study

    NASA Astrophysics Data System (ADS)

    Shivade, Rajendra K.; Chakraborty, Brahmananda

    2016-09-01

    Boron nano-clusters of various shapes and sizes have potential applications as scintillating detector and hydrogen storage material. Using time dependent density functional theory (TDDFT) as implemented in CASIDA we have studied the linear optical absorption spectra for boron clusters B n ( n = 2-5) and compared with previously reported results using Hatree-Fock (H-F) based method where the spectrum is limited to 8 eV due to exclusion of excitation into very high energy unoccupied orbital. The optical spectra fall in the visible and near UV region and are very much dependent on the shape of the isomer. We have obtained additional peaks for B2 linear, B3 triangular, B4 rhombus and square shaped isomers beyond 8 eV which were missing in the previous H-F based study and has significance as they fall below the ionization potential. We correlate the optical spectrum with the shape of the Kohn-Sham orbitals and HUMO-LUMO gap and assess comparative stability of various B n ( n = 2-5) clusters in terms of HUMO-LUMO gap, bond-length and relative energy. TDDFT computed optical spectroscopy correlated with Kohn-Sham orbitals and HUMO-LUMO gap and its comparison with H-F based method may give significant knowledge regarding geometry and optical properties of B n ( n = 2-5) clusters enabling to distingush between various isomers of B n clusters.

  1. Time-Resolved Gas-Phase Kinetic, Quantum Chemical, and RRKM Studies of the Reaction of Silylene with 2,5-Dihydrofuran.

    PubMed

    Becerra, Rosa; Cannady, J Pat; Pfrang, Christian; Walsh, Robin

    2015-11-19

    Time-resolved kinetics studies of silylene, SiH2, generated by laser flash photolysis of phenylsilane, were performed to obtain rate coefficients for its bimolecular reaction with 2,5-dihydrofuran (2,5-DHF). The reaction was studied in the gas phase over the pressure range of 1-100 Torr in SF6 bath gas, at five temperatures in the range of 296-598 K. The reaction showed pressure dependences characteristic of a third body assisted association. The second-order rate coefficients obtained by Rice-Ramsperger-Kassel-Marcus (RRKM)-assisted extrapolation to the high-pressure limit at each temperature fitted the following Arrhenius equation where the error limits are single standard deviations: log(k/cm(3) molecule(-1) s(-1)) = (-9.96 ± 0.08) + (3.38 ± 0.62 kJ mol(-1))/RT ln 10. End-product analysis revealed no GC-identifiable product. Quantum chemical (ab initio) calculations indicate that reaction of SiH2 with 2,5-DHF can occur at both the double bond (to form a silirane) and the O atom (to form a donor-acceptor, zwitterionic complex) via barrierless processes. Further possible reaction steps were explored, of which the only viable one appears to be decomposition of the O-complex to give 1,3-butadiene + silanone, although isomerization of the silirane cannot be completely ruled out. The potential energy surface for SiH2 + 2,5-DHF is consistent with that of SiH2 with Me2O, and with that of SiH2 with cis-but-2-ene, the simplest reference reactions. RRKM calculations incorporating reaction at both π- and O atom sites, can be made to fit the experimental rate coefficient pressure dependence curves at 296-476 K, giving values for k(∞)(π) and k(∞)(O) that indicate the latter is larger in magnitude at all temperatures, in contrast to values from individual model reactions. This unexpected result suggests that, in 2,5-DHF with its two different reaction sites, the O atom exerts the more pronounced electrophilic attraction on the approaching silylene. Arrhenius parameters

  2. Stochastic univariate and multivariate time series analysis of PM2.5 and PM10 air pollution: A comparative case study for Plovdiv and Asenovgrad, Bulgaria

    NASA Astrophysics Data System (ADS)

    Gocheva-Ilieva, S.; Stoimenova, M.; Ivanov, A.; Voynikova, D.; Iliev, I.

    2016-10-01

    Fine particulate matter PM2.5 and PM10 air pollutants are a serious problem in many urban areas affecting both the health of the population and the environment as a whole. The availability of large data arrays for the levels of these pollutants makes it possible to perform statistical analysis, to obtain relevant information, and to find patterns within the data. Research in this field is particularly topical for a number of Bulgarian cities, European country, where in recent years regulatory air pollution health limits are constantly being exceeded. This paper examines average daily data for air pollution with PM2.5 and PM10, collected by 3 monitoring stations in the cities of Plovdiv and Asenovgrad between 2011 and 2016. The goal is to find and analyze actual relationships in data time series, to build adequate mathematical models, and to develop short-term forecasts. Modeling is carried out by stochastic univariate and multivariate time series analysis, based on Box-Jenkins methodology. The best models are selected following initial transformation of the data and using a set of standard and robust statistical criteria. The Mathematica and SPSS software were used to perform calculations. This examination showed measured concentrations of PM2.5 and PM10 in the region of Plovdiv and Asenovgrad regularly exceed permissible European and national health and safety thresholds. We obtained adequate stochastic models with high statistical fit with the data and good quality forecasting when compared against actual measurements. The mathematical approach applied provides an independent alternative to standard official monitoring and control means for air pollution in urban areas.

  3. Correlating MODIS aerosol optical thickness data with ground-based PM 2.5 observations across Texas for use in a real-time air quality prediction system

    NASA Astrophysics Data System (ADS)

    Hutchison, Keith D.; Smith, Solar; Faruqui, Shazia J.

    Investigations have been conducted at the Center for Space Research (CSR) into approaches to correlate MODIS aerosol optical thickness (AOT) values with ground-based, PM 2.5 observations made at continuous air monitoring station locations operated by the Texas Commission on Environmental Quality (TCEQ). These correlations are needed to more fully utilize real-time MODIS AOT analyses generated at CSR in operational air quality forecasts issued by TCEQ using a trajectory-based forecast model developed by NASA. Initial analyses of two data sets collected during 3 months in 2003 and all of 2004 showed linear correlations in the 0.4-0.5 range in the data collected over Texas. Stronger correlations (exceeding 0.9) were obtained by averaging these same data over longer timescales but this approach is considered unsuitable for use in issuing air quality forecasts. Peculiarities in the MODIS AOT analyses, referred to as hot spots, were recognized while attempting to improve these correlations. It is demonstrated that hot spots are possible when pixels that contain surface water are not detected and removed from the AOT retrieval algorithms. An approach to reduce the frequency of hot spots in AOT analyses over Texas is demonstrated by tuning thresholds used to detect inland water surfaces and remove pixels that contain them from the analysis. Finally, the potential impact of hot spots on MODIS AOT-PM 2.5 correlations is examined through the analysis of a third data set that contained sufficient levels of aerosols to mask inland water surfaces from the AOT algorithms. In this case, significantly stronger correlations, that exceed the 0.9 value considered suitable for use in a real-time air quality prediction system, were observed between the MODIS AOT observations and ground-based PM 2.5 measurements.

  4. Does the Timing of Tracking Affect Higher Education Completion?

    ERIC Educational Resources Information Center

    van Elk, Roel; van der Steeg, Marc; Webbink, Dinand

    2011-01-01

    This paper investigates the effect of the timing of tracking on completion of higher education by exploiting unique variation from the Dutch education system. At the age of 12 Dutch students can enrol in tracked schools or in comprehensive schools. The comprehensive schools postpone enrolment into tracked classes by one or two years. OLS- and…

  5. Naked singularities in higher dimensional Vaidya space-times

    SciTech Connect

    Ghosh, S. G.; Dadhich, Naresh

    2001-08-15

    We investigate the end state of the gravitational collapse of a null fluid in higher-dimensional space-times. Both naked singularities and black holes are shown to be developing as the final outcome of the collapse. The naked singularity spectrum in a collapsing Vaidya region (4D) gets covered with the increase in dimensions and hence higher dimensions favor a black hole in comparison to a naked singularity. The cosmic censorship conjecture will be fully respected for a space of infinite dimension.

  6. Investigation of the time evolved spatial distribution of urban PM2.5 concentrations and aerosol composition during episodic high PM events in Yuma, AZ

    NASA Astrophysics Data System (ADS)

    Holmes, Heather A.; Pardyjak, Eric R.; Tyler, Bonnie J.; Peterson, Richard E.

    An interdisciplinary field study designed to investigate the spatial and temporal variability of atmospheric aerosols during high particulate matter ( PM) events along the US-Mexico border near Yuma, AZ was run during the week of March 18, 2007. The experiments were designed to quantify chemical composition and physical phenomena governing the transport of aerosols generated from episodic high PM events. The field study included two micrometeorological monitoring sites; one rural and one urban, equipped with sonic anemometers, continuous particulate concentration monitors and ambient aerosol collection equipment. In addition to the two main monitoring sites, five additional locations were equipped with optical particle counters to allow for the investigation of the spatial and temporal distribution of PM2.5 in the urban environment. In this paper, the meteorological and turbulence parameters governing the distribution and concentration of PM2.5 in the urban environment for two high-wind erosion events and one burning event are compared. The interaction between local atmospheric conditions and the particulate distribution is investigated. Results indicate that a single point measurement in the urban area of Yuma may not be sufficient for determining the ambient PM concentrations that the local population experiences; all three high PM events indicated PM2.5 varied considerably with maximum urban concentrations 5-10 times greater than the measured minima. A comparison of inorganic and carbonaceous content of the aerosols for the three high PM events is presented. The comparison shows an increase in silicon during crustal dust events and an increase in elemental and organic carbon during the burn event. Additional surface chemistry analysis, using time-of-flight secondary ion mass spectrometry (ToF-SIMS), for aerosols collected at the urban and rural sites during the burn event are discussed. The surface chemistry analysis provides positive ion mass spectra of organic

  7. Programming real-time executives in higher order language

    NASA Technical Reports Server (NTRS)

    Foudriat, E. C.

    1982-01-01

    Methods by which real-time executive programs can be implemented in a higher order language are discussed, using HAL/S and Path Pascal languages as program examples. Techniques are presented by which noncyclic tasks can readily be incorporated into the executive system. Situations are shown where the executive system can fail to meet its task scheduling and yet be able to recover either by rephasing the clock or stacking the information for later processing. The concept of deadline processing is shown to enable more effective mixing of time and information synchronized systems.

  8. Real-time operating systems at higher control

    SciTech Connect

    Jensen, E.D.

    1995-01-01

    Although virtually all development of real-time operating systems focuses on the lowest of the three traditional control levels, sheet economics demands higher level real-time OSs. Meeting this demand requires a major change in the mindset of the people who have been focusing on the lowest level of control. {open_quotes}These people are trying to deal with an elephant`s tail, but they don`t realize that there is an elephant attached to it.{close_quotes} For more than three decades, the historical real-time mindset, concepts and techniques have been driven by a particular pair of contexts. First is the application context, which can be characterized as {open_quotes}small, simple, centralized, static subsystems for low-level, sampled data, monitoring and first-order control.{close_quotes} Second is the hardware context, characterized by a scarcity of hardware resources due to size, weight, power and cost considerations. Both of these contexts are changing dramatically in ways that {open_quotes}have a significant impact on the concepts and techniques of real-time computing.{close_quotes} Hardware now offers much higher performance and the real-time domain is expanding upward in the application control hierarchy.

  9. Full-Time Students? Term-Time Employment among Higher Education Students in Ireland

    ERIC Educational Resources Information Center

    Darmody, Merike; Smyth, Emer

    2008-01-01

    A good deal of research has focused on part-time employment among full-time students in higher education. However, little attention has been paid to the way in which these patterns may reflect societally specific processes rather than universal trends. This paper examines ways in which the higher education system itself can influence variation in…

  10. Late-time acceleration in higher dimensional cosmology

    SciTech Connect

    Pahwa, Isha; Choudhury, Debajyoti; Seshadri, T.R. E-mail: debajyoti.choudhury@gmail.com

    2011-09-01

    We investigate late time acceleration of the universe in higher dimensional cosmology. The content in the universe is assumed to exert pressure which is different in the normal and extra dimensions. Cosmologically viable solutions are found to exist for simple forms of the equation of state. The parameters of the model are fixed by comparing the predictions with supernovae data. While observations stipulate that the matter exerts almost vanishing pressure in the normal dimensions, we assume that, in the extra dimensions, the equation of state is of the form P∝ρ{sup 1−γ}. For appropriate choice of parameters, a late time acceleration in the universe occurs with q{sub 0} and z{sub tr} being approximately -0.46 and 0.76 respectively.

  11. PM 2.5 characterization for time series studies: Organic molecular marker speciation methods and observations from daily measurements in Denver

    NASA Astrophysics Data System (ADS)

    Dutton, Steven J.; Williams, Daniel E.; Garcia, Jessica K.; Vedal, Sverre; Hannigan, Michael P.

    Particulate matter less than 2.5 microns in diameter (PM 2.5) has been shown to have a wide range of adverse health effects and consequently is regulated in accordance with the US-EPA's National Ambient Air Quality Standards. PM 2.5 originates from multiple primary sources and is also formed through secondary processes in the atmosphere. It is plausible that some sources form PM 2.5 that is more toxic than PM 2.5 from other sources. Identifying the responsible sources could provide insight into the biological mechanisms causing the observed health effects and provide a more efficient approach to regulation. This is the goal of the Denver Aerosol Sources and Health (DASH) study, a multi-year PM 2.5 source apportionment and health study. The first step in apportioning the PM 2.5 to different sources is to determine the chemical make-up of the PM 2.5. This paper presents the methodology used during the DASH study for organic speciation of PM 2.5. Specifically, methods are covered for solvent extraction of non-polar and semi-polar organic molecular markers using gas chromatography-mass spectrometry (GC-MS). Vast reductions in detection limits were obtained through the use of a programmable temperature vaporization (PTV) inlet along with other method improvements. Results are presented for the first 1.5 years of the DASH study revealing seasonal and source-related patterns in the molecular markers and their long-term correlation structure. Preliminary analysis suggests that point sources are not a significant contributor to the organic molecular markers measured at our receptor site. Several motor vehicle emission markers help identify a gasoline/diesel split in the ambient data. Findings show both similarities and differences when compared with other cities where similar measurements and assessments have been made.

  12. PM2.5 Characterization for Time Series Studies: Organic Molecular Marker Speciation Methods and Observations from Daily Measurements in Denver

    PubMed Central

    Dutton, Steven J.; Williams, Daniel E.; Garcia, Jessica K.; Vedal, Sverre; Hannigan, Michael P.

    2009-01-01

    Particulate matter less than 2.5 microns in diameter (PM2.5) has been shown to have a wide range of adverse health effects and consequently is regulated in accordance with the US-EPA’s National Ambient Air Quality Standards. PM2.5 originates from multiple primary sources and is also formed through secondary processes in the atmosphere. It is plausible that some sources form PM2.5 that is more toxic than PM2.5 from other sources. Identifying the responsible sources could provide insight into the biological mechanisms causing the observed health effects and provide a more efficient approach to regulation. This is the goal of the Denver Aerosol Sources and Health (DASH) study, a multi-year PM2.5 source apportionment and health study. The first step in apportioning the PM2.5 to different sources is to determine the chemical make-up of the PM2.5. This paper presents the methodology used during the DASH study for organic speciation of PM2.5. Specifically, methods are covered for solvent extraction of non-polar and semi-polar organic molecular markers using gas chromatography-mass spectrometry (GC-MS). Vast reductions in detection limits were obtained through the use of a programmable temperature vaporization (PTV) inlet along with other method improvements. Results are presented for the first 1.5 years of the DASH study revealing seasonal and source-related patterns in the molecular markers and their long-term correlation structure. Preliminary analysis suggests that point sources are not a significant contributor to the organic molecular markers measured at our receptor site. Several motor vehicle emission markers help identify a gasoline/diesel split in the ambient data. Findings show both similarities and differences when compared with other cities where similar measurements and assessments have been made. PMID:20161318

  13. The extraordinary ability of guanidinate derivatives to stabilize higher oxidation numbers in dimetal units by modification of redox potentials: structures of Mo(2)(5+) and Mo(2)(6+) compounds.

    PubMed

    Cotton, F Albert; Daniels, Lee M; Murillo, Carlos A; Timmons, Daren J; Wilkinson, Chad C

    2002-08-01

    Full characterization of the first homologous series of dimolybdenum paddlewheel compounds having electronic configurations of the types sigma(2)pi(4)delta(x), x = 2, 1, 0, and Mo-Mo bond orders of 4, 3.5, and 3, respectively, has been accomplished with the guanidinate-type ligand hpp (hpp = the anion of 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine). Essentially quantitative oxidation of Mo(2)(hpp)(4), 1, by CH(2)Cl(2) gives Mo(2)(hpp)(4)Cl, 2. The halide in 2 can be replaced by reaction with TlBF(4) to produce Mo(2)(hpp)(4)(BF(4)), 3. Further oxidation of 2 by AgBF(4) produces Mo(2)(hpp)(4)ClBF(4), 4. The change from bond order 4 (in 1) to 3.5 in Mo(2)(hpp)(4)Cl is accompanied by an increase in the Mo-Mo bond length of 0.061 to 2.1280(4) A. A further increase of 0.044 A in the Mo-Mo distance to 2.172(1) A is observed as the bond order decreases to 3 in 4. At the same time, the Mo-N distances decrease smoothly as the oxidation state of the Mo atoms increases. Electrochemical studies have shown two chemically reversible processes at very negative potentials, E(1)(1/2)= -0.444 V and E(2)(1/2)= -1.271 V versus Ag/AgCl. These correspond to the processes Mo(2)(6+/5+) and Mo(2)(5+/4+), respectively. The latter potential is displaced by over 1.5 V relative to those of the Mo(2)(formamidinate)(4) compounds and the first one has never been observed in such complexes. Thus, in surprising contrast to previously observed behavior of the dimolybdenum unit, when it is surrounded by the very basic guanidinate ligand hpp, there is an extraordinary stabilization of the higher oxidation numbers of the molybdenum atoms.

  14. Pulse transmission transmitter including a higher order time derivate filter

    DOEpatents

    Dress, Jr., William B.; Smith, Stephen F.

    2003-09-23

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission transmitter includes: a clock; a pseudorandom polynomial generator coupled to the clock, the pseudorandom polynomial generator having a polynomial load input; an exclusive-OR gate coupled to the pseudorandom polynomial generator, the exclusive-OR gate having a serial data input; a programmable delay circuit coupled to both the clock and the exclusive-OR gate; a pulse generator coupled to the programmable delay circuit; and a higher order time derivative filter coupled to the pulse generator. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  15. Measuring Stratigraphic Congruence Across Trees, Higher Taxa, and Time

    PubMed Central

    O'Connor, Anne; Wills, Matthew A.

    2016-01-01

    The congruence between the order of cladistic branching and the first appearance dates of fossil lineages can be quantified using a variety of indices. Good matching is a prerequisite for the accurate time calibration of trees, while the distribution of congruence indices across large samples of cladograms has underpinned claims about temporal and taxonomic patterns of completeness in the fossil record. The most widely used stratigraphic congruence indices are the stratigraphic consistency index (SCI), the modified Manhattan stratigraphic measure (MSM*), and the gap excess ratio (GER) (plus its derivatives; the topological GER and the modified GER). Many factors are believed to variously bias these indices, with several empirical and simulation studies addressing some subset of the putative interactions. This study combines both approaches to quantify the effects (on all five indices) of eight variables reasoned to constrain the distribution of possible values (the number of taxa, tree balance, tree resolution, range of first occurrence (FO) dates, center of gravity of FO dates, the variability of FO dates, percentage of extant taxa, and percentage of taxa with no fossil record). Our empirical data set comprised 647 published animal and plant cladograms spanning the entire Phanerozoic, and for these data we also modeled the effects of mean age of FOs (as a proxy for clade age), the taxonomic rank of the clade, and the higher taxonomic group to which it belonged. The center of gravity of FO dates had not been investigated hitherto, and this was found to correlate most strongly with some measures of stratigraphic congruence in our empirical study (top-heavy clades had better congruence). The modified GER was the index least susceptible to bias. We found significant differences across higher taxa for all indices; arthropods had lower congruence and tetrapods higher congruence. Stratigraphic congruence—however measured—also varied throughout the Phanerozoic

  16. Measuring Stratigraphic Congruence Across Trees, Higher Taxa, and Time.

    PubMed

    O'Connor, Anne; Wills, Matthew A

    2016-09-01

    The congruence between the order of cladistic branching and the first appearance dates of fossil lineages can be quantified using a variety of indices. Good matching is a prerequisite for the accurate time calibration of trees, while the distribution of congruence indices across large samples of cladograms has underpinned claims about temporal and taxonomic patterns of completeness in the fossil record. The most widely used stratigraphic congruence indices are the stratigraphic consistency index (SCI), the modified Manhattan stratigraphic measure (MSM*), and the gap excess ratio (GER) (plus its derivatives; the topological GER and the modified GER). Many factors are believed to variously bias these indices, with several empirical and simulation studies addressing some subset of the putative interactions. This study combines both approaches to quantify the effects (on all five indices) of eight variables reasoned to constrain the distribution of possible values (the number of taxa, tree balance, tree resolution, range of first occurrence (FO) dates, center of gravity of FO dates, the variability of FO dates, percentage of extant taxa, and percentage of taxa with no fossil record). Our empirical data set comprised 647 published animal and plant cladograms spanning the entire Phanerozoic, and for these data we also modeled the effects of mean age of FOs (as a proxy for clade age), the taxonomic rank of the clade, and the higher taxonomic group to which it belonged. The center of gravity of FO dates had not been investigated hitherto, and this was found to correlate most strongly with some measures of stratigraphic congruence in our empirical study (top-heavy clades had better congruence). The modified GER was the index least susceptible to bias. We found significant differences across higher taxa for all indices; arthropods had lower congruence and tetrapods higher congruence. Stratigraphic congruence-however measured-also varied throughout the Phanerozoic, reflecting

  17. Time-resolved spectral imaging: better photon economy, higher accuracy

    NASA Astrophysics Data System (ADS)

    Fereidouni, Farzad; Reitsma, Keimpe; Blab, Gerhard A.; Gerritsen, Hans C.

    2015-03-01

    Lifetime and spectral imaging are complementary techniques that offer a non-invasive solution for monitoring metabolic processes, identifying biochemical compounds, and characterizing their interactions in biological tissues, among other tasks. Newly developed instruments that perform time-resolved spectral imaging can provide even more information and reach higher sensitivity than either modality alone. Here we report a multispectral lifetime imaging system based on a field-programmable gate array (FPGA), capable of operating at high photon count rates (12 MHz) per spectral detection channel, and with time resolution of 200 ps. We performed error analyses to investigate the effect of gate width and spectral-channel width on the accuracy of estimated lifetimes and spectral widths. Temporal and spectral phasors were used for analysis of recorded data, and we demonstrated blind un-mixing of the fluorescent components using information from both modalities. Fractional intensities, spectra, and decay curves of components were extracted without need for prior information. We further tested this approach with fluorescently doubly-labeled DNA, and demonstrated its suitability for accurately estimating FRET efficiency in the presence of either non-interacting or interacting donor molecules.

  18. Observational evidence that massive cluster galaxies were forming stars at z ~ 2.5 and did not grow in mass at later times

    NASA Astrophysics Data System (ADS)

    Andreon, S.

    2013-06-01

    Using Spitzer 3.6 micron data we derived the luminosity function and the mass function of galaxies in five z > 1.4 clusters selected to have a firm intracluster medium detection. The five clusters differ in richness (ISCS J1438.1+3414 and XMMXCS J2215.9-1738 are twice as rich as ISCS J1432.4+3250, IDCS J1426.5+3508, and JKCS 041) and morphological appareance. At the median redshift z = 1.5, from the 150 member galaxies of the five clusters, we derived a characteristic magnitude of 16.92 ± 0.13 in the [3.6] band and a characteristic mass of lg M∗ = 11.30 ± 0.05 M⊙. We find that the characteristic luminosity and mass does not evolve between z = 1 and 1.4 < z < 1.8, directly ruling out ongoing mass assembly between these epochs because massive galaxies are already present up to z = 1.8. Lower-redshift build-up epochs have already been ruled out by previous works, leaving only z > 1.8 as a possible epoch for the mass build up. However, the observed values of m∗ at very high redshift are too bright for galaxies without any star formation immediately preceding the observed redshift and therefore imply a star formation episode not earlier than zf = 2.5. For the first time, mass/luminosity functions are able to robustly distinguish tiny differences between formation redshifts and to set upper limits to the epoch of the last star-formation episode.

  19. Comparative study using oral solutions of bambuterol once daily or terbutaline three times daily in 2-5-year-old children with asthma. Bambuterol Multicentre Study Group.

    PubMed

    Kuusela, A L; Marenk, M; Sandahl, G; Sanderud, J; Nikolajev, K; Persson, B

    2000-03-01

    The aim of this study was to compare safety and efficacy of bambuterol hydrochloride (10 mg) oral solution administered once daily in the evening with terbutaline sulphate (0.075 mg/kg body weight) oral solution administered three times daily in 2-5-year-old children with asthma. There were two treatment groups: (2/3) of the patients received bambuterol and (1/3) received terbutaline. The study was double-blind, randomized, and of a parallel group design, and it lasted for 3 months after a 2-week run-in period. The primary objective was to evaluate safety (adverse events, and changes in blood pressure, pulse rate, hematology, and clinical chemistry parameters). Plasma concentrations of terbutaline and/or bambuterol were also measured. Evaluation of efficacy (diary card data) was a secondary objective. A total of 155 patients (range, 2-6 years; 3 patients were 6 years old at randomization) were treated with the study drugs; 104 patients received bambuterol and 51 patients received terbutaline. Both treatments showed a good safety profile with respect to clinical and laboratory tests, and they were generally well tolerated. Reported adverse events were mild to moderate. There were no statistically significant differences between treatment groups in any of the efficacy variables (diary variables: peak expiratory flow (PEF), asthma symptoms, restlessness, other reported symptoms, use of inhaled bronchodilators, and nighttime awakenings). For morning PEF, the mean increase from run-in to treatment was 16.9 L/min in the terbutaline group and 23.3 L/min in the bambuterol group. For evening PEF, the mean increase was 20.2 L/min in the terbutaline group and 20.6 L/min in the bambuterol group. In conclusion, once-daily bambuterol is as safe and effective as terbutaline given three times daily. The study also confirmed that bambuterol has a 24-hr duration of action, and therefore its once daily administration, makes it a preferred bronchodilator agent. Pediatr Pulmonol. 2000

  20. Advancing Knowledge in Higher Education: Universities in Turbulent Times

    ERIC Educational Resources Information Center

    Fitzgerald, Tanya, Ed.

    2014-01-01

    Over the last three decades, higher education institutions have experienced massive changes. In particular, institutions of higher education have been positioned as a means to contribute to the knowledge economy and gain a level of competitive advantage in the global marketplace. "Advancing Knowledge in Higher Education: Universities in…

  1. Synthesis of 2,5-bis(spirocyclohexane)-substituted nitroxides of pyrroline and pyrrolidine series, including thiol-specific spin label: an analogue of MTSSL with long relaxation time.

    PubMed

    Kirilyuk, Igor A; Polienko, Yuliya F; Krumkacheva, Olesya A; Strizhakov, Rodion K; Gatilov, Yurii V; Grigor'ev, Igor A; Bagryanskaya, Elena G

    2012-09-21

    The nitroxides of 7-azadispiro[5.1.5.2]pentadecane and 7-azadispiro[5.1.5.2]pentadeca-14-ene series have been prepared, including thiol-specific methane thiosulfonate spin label for site-directed spin labeling. The effect of spirocyclohexane moieties on chemical and spectral properties has been studied. The obtained temperature dependencies of electron spin relaxation parameters demonstrate that new nitroxides may be suitable for PELDOR distance measurements at 80-120 K. Moreover, the new nitroxides demonstrated much higher stability toward reduction by ascorbate than spirocyclohexane-substituted nitroxides of piperidine series and showed 1.3-3.14 times lower reduction rates compared to corresponding 2,2,5,5-tetramethyl nitroxides. PMID:22917445

  2. Chemical composition of PM10 and PM2.5 collected at ground level and 100 meters during a strong winter-time pollution episode in Xi'an, China.

    PubMed

    Shen, Zhenxing; Cao, Junji; Liu, Suixin; Zhu, Chongshu; Wang, Xin; Zhang, Ting; Xu, Hongmei; Hu, Tafeng

    2011-11-01

    An intensive sampling of aerosol particles from ground level and 100 m was conducted during a strong pollution episode during the winter in Xi'an, China. Concentrations of water-soluble inorganic ions, carbonaceous compounds, and trace elements were determined to compare the composition of particulate matter (PM) at the two heights. PM mass concentrations were high at both stations: PM10 (PM with aerodynamic diameter < or =10 microm) exceeded the China National Air Quality Standard Class II value on three occasions, and PM2.5 (PM with aerodynamic diameter < or =2.5 microm) exceeded the daily U.S. National Ambient Air Quality Standard more than 10 times. The PM10 organic carbon (OC) and elemental carbon (EC) were slightly lower at the ground than at 100 m, both in terms of concentration and percentage of total mass, but OC and EC in PM2.5 exhibited the opposite pattern. Major ionic species, such as sulfate and nitrate, showed vertical variations similar to the carbonaceous aerosols. High sulfate concentrations indicated that coal combustion dominated the PM mass both at the ground and 100 m. Correlations between K+ and OC and EC at 100 m imply a strong influence from suburban biomass burning, whereas coal combustion and motor vehicle exhaust had a greater influence on the ground PM. Stable atmospheric conditions apparently led to the accumulation of PM, especially at 100 m, and these conditions contributed to the similarities in PM at the two elevations. Low coefficient of divergence (CD) values reflect the similarities in the composition of the aerosol between sites, but higher CDs for fine particles compared with coarse ones were consistent with the differences in emission sources between the ground and 100 m.

  3. Kerb and urban increment of highly time-resolved trace elements in PM10, PM2.5 and PM1.0 winter aerosol in London during ClearfLo 2012

    NASA Astrophysics Data System (ADS)

    Visser, S.; Slowik, J. G.; Furger, M.; Zotter, P.; Bukowiecki, N.; Dressler, R.; Flechsig, U.; Appel, K.; Green, D. C.; Tremper, A. H.; Young, D. E.; Williams, P. I.; Allan, J. D.; Herndon, S. C.; Williams, L. R.; Mohr, C.; Xu, L.; Ng, N. L.; Detournay, A.; Barlow, J. F.; Halios, C. H.; Fleming, Z. L.; Baltensperger, U.; Prévôt, A. S. H.

    2014-06-01

    Ambient concentrations of trace elements with 2 h time resolution were measured in PM10-2.5, PM2.5-1.0 and PM1.0-0.3 size ranges at kerbside, urban background and rural sites in London during winter 2012. Samples were collected using rotating drum impactors (RDIs) and subsequently analysed with synchrotron radiation-induced X-ray fluorescence spectrometry (SR-XRF). Quantification of kerb and urban increments (defined as kerb-to-urban and urban-to-rural concentration ratios, respectively), and assessment of diurnal and weekly variability provided insight into sources governing urban air quality and the effects of urban micro-environments on human exposure. Traffic-related elements yielded the highest kerb increments, with values in the range of 11.6 to 18.5 for SW winds (3.6-9.4 for NE) observed for elements influenced by brake wear (e.g. Cu, Sb, Ba) and 5.6 to 8.0 for SW (2.6-6.5 for NE) for other traffic-related processes (e.g. Cr, Fe, Zn). Kerb increments for these elements were highest in the PM10-2.5 mass fraction, roughly 3 times that of the PM1.0-0.3 fraction. These elements also showed the highest urban increments (∼3.0), although no difference was observed between brake wear and other traffic-related elements. Traffic-related elements exhibited higher concentrations during morning and evening rush hour, and on weekdays compared to weekends, with the strongest trends observed at the kerbside site, and additionally enhanced by winds coming directly from the road, consistent with street canyon effects. Elements related to mineral dust (e.g. Al, Ca, Sr) showed significant influences from traffic-induced resuspension, as evidenced by moderate kerb (2.0-4.1 for SW, 1.4-2.1 for NE) and urban (1.7-2.3) increments and increased concentrations during peak traffic flow. Elements related to regional transport showed no significant enhancement at kerb or urban sites, with the exception of PM10-2.5 sea salt (factor of 1.5-2.0), which may be influenced by traffic

  4. INTERCOMPARISON OF NEAR REAL-TIME MONITORS OF PM2.5 NITRATE AND SULFATE AT THE U.S. ENVIRONMENTAL PROTECTION AGENCY ATLANTA SUPERSITE

    EPA Science Inventory

    Five new instruments for semi-continuous measurements of fine particle (PM2.5) nitrate and sulfate were deployed at the Atlanta Supersite Experiment during an intensive study in August 1999. The instruments measured bulk aerosol chemical composition at rates ranging from every...

  5. California's "Gold Standard" for Higher Education Falls Upon Hard Times

    ERIC Educational Resources Information Center

    Keller, Josh

    2009-01-01

    Few documents in higher education have enjoyed the influence or longevity of the California Master Plan for Higher Education, the 1960 law that transformed the state's public colleges and served as a blueprint for public systems across the country. Even today, almost 50 years after it was written, the master plan retains a mythic status in…

  6. Time Management and Academic Achievement of Higher Secondary Students

    ERIC Educational Resources Information Center

    Cyril, A. Vences

    2015-01-01

    The only thing, which can't be changed by man, is time. One cannot get back time lost or gone Nothing can be substituted for time. Time management is actually self management. The skills that people need to manage others are the same skills that are required to manage themselves. The purpose of the present study was to explore the relation between…

  7. Kerb and urban increment of highly time-resolved trace elements in PM10, PM2.5 and PM1.0 winter aerosol in London during ClearfLo 2012

    NASA Astrophysics Data System (ADS)

    Visser, S.; Slowik, J. G.; Furger, M.; Zotter, P.; Bukowiecki, N.; Dressler, R.; Flechsig, U.; Appel, K.; Green, D. C.; Tremper, A. H.; Young, D. E.; Williams, P. I.; Allan, J. D.; Herndon, S. C.; Williams, L. R.; Mohr, C.; Xu, L.; Ng, N. L.; Detournay, A.; Barlow, J. F.; Halios, C. H.; Fleming, Z. L.; Baltensperger, U.; Prévôt, A. S. H.

    2015-03-01

    Ambient concentrations of trace elements with 2 h time resolution were measured in PM10-2.5, PM2.5-1.0 and PM1.0-0.3 size ranges at kerbside, urban background and rural sites in London during winter 2012. Samples were collected using rotating drum impactors (RDIs) and subsequently analysed with synchrotron radiation-induced X-ray fluorescence spectrometry (SR-XRF). Quantification of kerb and urban increments (defined as kerb-to-urban and urban-to-rural concentration ratios, respectively), and assessment of diurnal and weekly variability provided insight into sources governing urban air quality and the effects of urban micro-environments on human exposure. Traffic-related elements yielded the highest kerb increments, with values in the range of 10.4 to 16.6 for SW winds (3.3-6.9 for NE) observed for elements influenced by brake wear (e.g. Cu, Sb, Ba) and 5.7 to 8.2 for SW (2.6-3.0 for NE) for other traffic-related processes (e.g. Cr, Fe, Zn). Kerb increments for these elements were highest in the PM10-2.5 mass fraction, roughly twice that of the PM1.0-0.3 fraction. These elements also showed the highest urban increments (~ 3.0), although no difference was observed between brake wear and other traffic-related elements. All elements influenced by traffic exhibited higher concentrations during morning and evening rush hours, and on weekdays compared to weekends, with the strongest trends observed at the kerbside site, and additionally enhanced by winds coming directly from the road, consistent with street canyon effects. Elements related to mineral dust (e.g. Al, Si, Ca, Sr) showed significant influences from traffic-induced resuspension, as evidenced by moderate kerb (3.4-5.4 for SW, 1.7-2.3 for NE) and urban (~ 2) increments and increased concentrations during peak traffic flow. Elements related to regional transport showed no significant enhancement at kerb or urban sites, with the exception of PM10-2.5 sea salt (factor of up to 2), which may be influenced by

  8. Characterization of PM2.5, gaseous pollutants, and meteorological interactions in the context of time-series health effects models.

    PubMed

    Ito, Kazuhiko; Thurston, George D; Silverman, Robert A

    2007-12-01

    Associations of particulate matter (PM) and ozone with morbidity and mortality have been reported in many recent observational epidemiology studies. These studies often considered other gaseous co-pollutants also as potential confounders, including nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO). However, because each of these air pollutants can have different seasonal patterns and chemical interactions, the estimation and interpretation of each pollutant's individual risk estimates may not be straightforward. Multi-collinearity among the air pollution and weather variables also leaves the possibility of confounding and over- or under-fitting of meteorological variables, thereby potentially influencing the health effect estimates for the various pollutants in differing ways. To investigate these issues, we examined the temporal relationships among air pollution and weather variables in the context of air pollution health effects models. We compiled daily data for PM less than 2.5 mum (PM2.5), ozone, NO2, SO2, CO, temperature, dew point, relative humidity, wind speed, and barometric pressure for New York City for the years 1999-2002. We conducted several sets of analyses to characterize air pollution and weather data interactions, to assess different aspects of these data issues: (1) spatial/temporal variation of PM2.5 and gaseous pollutants measured at multiple monitors; (2) temporal relationships among air pollution and weather variables; and (3) extent and nature of multi-collinearity of air pollution and weather variables in the context of health effects models. The air pollution variables showed a varying extent of intercorrelations with each other and with weather variables, and these correlations also varied across seasons. For example, NO2 exhibited the strongest negative correlation with wind speed among the pollutants considered, while ozone's correlation with PM2.5 changed signs across the seasons (positive in summer and negative in

  9. Rebooting Irish Higher Education: Policy Challenges for Challenging Times

    ERIC Educational Resources Information Center

    Hazelkorn, Ellen

    2014-01-01

    The 2008 global financial crisis cast a long shadow over Ireland's higher education and research system. The IMF said Ireland experienced an "unprecedented economic correction", while Ireland's National Economic and Social Development Office said Ireland was beset by five different crises: a banking crisis, a fiscal crisis, an…

  10. Restyling the Humanities Curriculum of Higher Education for Posthuman Times

    ERIC Educational Resources Information Center

    Siddiqui, Jamila R.

    2016-01-01

    The future viability of the humanities in higher education has been broadly debated. Yet, most of these debates are missing an important consideration. The humanities' object of study is the human, an object that some would argue has been replaced in our onto-epistemological systems by the posthuman. In her 2013 book, "The Posthuman,"…

  11. Higher Education in Times of Financial Distress: The Minnesota Experience

    ERIC Educational Resources Information Center

    Severns, Roger

    2012-01-01

    Like many states, Minnesota has incurred large budget deficits during the past two years. Those deficits have, in turn, led to changes in a number of areas of state government, particularly higher education. Faculty have incurred pay freezes and layoffs, programs have closed, and tuition increased. Campuses within the MnSCU system have been…

  12. Time for Action to Bolster Future of Higher Education

    ERIC Educational Resources Information Center

    Spellings, Margaret

    2007-01-01

    Higher education in America had its origins in New England more than 350 years ago. Since then, America's colleges and universities have been the incubators of great ideas, birthplaces of great inventions, and testing grounds of great individuals. For generations of New Englanders, a college education has provided the opportunity to fully embrace…

  13. Creating Time: Students, Technologies and Temporal Practices in Higher Education

    ERIC Educational Resources Information Center

    Gourlay, Lesley

    2014-01-01

    The nature of time has been considered in some depth within philosophy and social theory, while theoreticians have also explored interrelationships between temporality, artefacts and social process. However, the notion of time in mainstream educational theory and research has arguably been regarded as fixed, naturalised, undifferentiated…

  14. Time Management in Higher Education Administration: A Case Study.

    ERIC Educational Resources Information Center

    Lewis, Darrell R.; Dahl, Tor

    How do departmental chairpersons and deans in a major university setting manage their time? What are the major administrative activities and functions associated with such responsibilities? What relationships do these have with an ability to delegate, to control one's time for planning and self-initiated activities, or personal sense of…

  15. Higher plant biomarkers reflect palaeovegetation changes during Jurassic times

    NASA Astrophysics Data System (ADS)

    van Aarssen, Ben G. K.; Alexander, Robert; Kagi, Robert I.

    2000-04-01

    The relative abundances of three higher-plant-derived biomarkers, retene, cadalene and ip-iHMN, have been measured in marine sedimentary rocks from the northwest margin of Australia. It is thought that each biomarker represents input from a different plant type. The distributions of these three compounds form a fingerprint, representing higher plant input (HPF). Variations in HPF in Oxfordian sediments were nearly identical in all three locations, with retene becoming very abundant relative to the other two compounds with decreasing age of the sediment. This finding strongly suggests that the composition of terrestrial input during deposition largely determines HPF and that the possible effects of diagenesis and catagenesis on the distribution of the three biomarkers are relatively unimportant. The marked increase in the abundance of retene relative to that of cadalene during the Oxfordian is interpreted to reflect an increase in the contribution of plants that produced precursors for retene, i.e., conifers, brought about by a significant change in climate. This was exemplified by measuring the distributions of retene and cadalene, expressed in the higher plant parameter (HPP) for a suite of sediments from the Carnarvon Basin, Western Australia, covering the complete Jurassic period. The HPP profile displays three major cycles, each covering a period of at least 10 million years. This profile not only compared well with published palaeoclimate data, but also showed a remarkable similarity with second order cycles in the global sea level curve, thus strongly supporting the proposal that variations in HPF and HPP are indications of changes in palaeoclimate. The relation with global sea level further suggests that global factors, e.g., the atmospheric carbon dioxide concentration, may play a major role in determining the observed variations in the distributions of these higher-plant-derived biomarkers.

  16. Identifying Optimal Temporal Scale for the Correlation of AOD and Ground Measurements of PM2.5 to Improve the Modeling Performance in a Real-Time Air Quality Estimation System

    NASA Technical Reports Server (NTRS)

    Li,Hui; Faruque, Fazlay; Williams, Worth; Al-Hamdan, Mohammad; Luvall, Jeffrey; Crosson, William; Rickman, Douglas; Limaye, Ashutosh

    2008-01-01

    Aerosol optical depth (AOD), derived from satellite measurements using Moderate Resolution Imaging Spectrometer (MODIS), offers indirect estimates of particle matter. Research shows a significant positive correlation between satellite-based measurements of AOD and ground-based measurements of particulate matter with aerodynamic diameter less than or equal to 2.5 micrometers (PM2.5). In addition, satellite observations have also shown great promise in improving estimates of PM2.5 air quality surface. Research shows that correlations between AOD and ground PM2.5 are affected by a combination of many factors such as inherent characteristics of satellite observations, terrain, cloud cover, height of the mixing layer, and weather conditions, and thus might vary widely in different regions, different seasons, and even different days in a same location. Analysis of correlating AOD with ground measured PM2.5 on a day-to-day basis suggests the temporal scale, a number of immediate latest days for a given run's day, for their correlations needs to be considered to improve air quality surface estimates, especially when satellite observations are used in a real-time pollution system. The second reason is that correlation coefficients between AOD and ground PM2.5 cannot be predetermined and needs to be calculated for each day's run for a real-time system because the coefficients can vary over space and time. Few studies have been conducted to explore the optimal way to apply AOD data to improve model accuracies of PM2.5 surface estimation in a real-time air quality system. This paper discusses the best temporal scale to calculate the correlation of AOD and ground particle matter data to improve the results of pollution models in real-time system.

  17. A new method for the rapid analysis of 1H-Pyrrole-2,5-diones (maleimides) in environmental samples by two-dimensional gas chromatography time-of-flight mass spectrometry.

    PubMed

    Naeher, Sebastian; Lengger, Sabine K; Grice, Kliti

    2016-02-26

    Maleimides (1H-Pyrrole-2,5-diones) are monopyrrolic pigment derivatives with specific alkyl side chains that can be directly linked to their tetrapyrrole precursors, most notably chlorophylls and bacteriochlorophylls. These compounds can be used as palaeoenvironmental indicators such as algal productivity and redox conditions in ancient and modern aquatic systems. Here, we present a new method using two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-ToF-MS), which enables the rapid analysis of maleimides in complex mixtures and different matrices (e.g. sediments and soils), therefore largely simplifying the previous intricate maleimide purification protocol. This method also reduces the potential for bias associated with partial losses due to low recovery and the high volatility of maleimides. The maleimide distributions and concentrations obtained by GC × GC-ToF-MS were reproducible and in agreement with the previously used purification procedure followed by analysis with traditional gas chromatography-mass spectrometry (GC-MS). The new method also resolved previously unrecognised, partial coelution of some maleimides with unknown compounds by quantification with the m/z 75 fragment ion. Furthermore, the higher sensitivity enabled the detection of previously unrecognised and preliminarily identified maleimides based on their relative retention times. The new, easier, rapid and more sensitive GC×GC-ToF-MS method greatly facilitates the analysis of maleimides in environmental samples to study tetrapyrrole degradation processes and will further the development of maleimides as biomarkers for palaeoenvironmental reconstructions. PMID:26850318

  18. A new method for the rapid analysis of 1H-Pyrrole-2,5-diones (maleimides) in environmental samples by two-dimensional gas chromatography time-of-flight mass spectrometry.

    PubMed

    Naeher, Sebastian; Lengger, Sabine K; Grice, Kliti

    2016-02-26

    Maleimides (1H-Pyrrole-2,5-diones) are monopyrrolic pigment derivatives with specific alkyl side chains that can be directly linked to their tetrapyrrole precursors, most notably chlorophylls and bacteriochlorophylls. These compounds can be used as palaeoenvironmental indicators such as algal productivity and redox conditions in ancient and modern aquatic systems. Here, we present a new method using two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-ToF-MS), which enables the rapid analysis of maleimides in complex mixtures and different matrices (e.g. sediments and soils), therefore largely simplifying the previous intricate maleimide purification protocol. This method also reduces the potential for bias associated with partial losses due to low recovery and the high volatility of maleimides. The maleimide distributions and concentrations obtained by GC × GC-ToF-MS were reproducible and in agreement with the previously used purification procedure followed by analysis with traditional gas chromatography-mass spectrometry (GC-MS). The new method also resolved previously unrecognised, partial coelution of some maleimides with unknown compounds by quantification with the m/z 75 fragment ion. Furthermore, the higher sensitivity enabled the detection of previously unrecognised and preliminarily identified maleimides based on their relative retention times. The new, easier, rapid and more sensitive GC×GC-ToF-MS method greatly facilitates the analysis of maleimides in environmental samples to study tetrapyrrole degradation processes and will further the development of maleimides as biomarkers for palaeoenvironmental reconstructions.

  19. Time Management in Higher Education Administration: A Case Study

    ERIC Educational Resources Information Center

    Lewis, Darrell R.; Dahl, Tor

    1976-01-01

    Drawing on data from a staff development project for administrators in a college at a major American university, it was determined that there is considerable commonality across individuals and that it is possible to deal with such issues as time management, job stress, and enjoyment on an organizational level. (Editor/JT)

  20. Effect of Reflow Time on Wetting Behavior, Microstructure Evolution, and Joint Strength of Sn-2.5Ag-0.5Cu Solder on Bare and Nickel-Coated Copper Substrates

    NASA Astrophysics Data System (ADS)

    Sona, Mrunali; Prabhu, K. Narayan

    2016-07-01

    The effect of reflow time on wetting behavior of Sn-2.5Ag-0.5Cu lead-free solder on bare and nickel-coated copper substrates has been investigated. The solder alloy was reflowed at 270°C for various reflow times of 10 s, 100 s, 300 s, and 500 s. On bare copper substrate, the intermetallic compound (IMC) thickness increased with increase in reflow time, whereas on Ni-coated Cu substrate, the IMC thickness increased up to 300 s followed by a drop for solder alloy reflowed for 500 s. The spreading behavior of the solder alloy was categorized into capillary, gravity (diffusion), and viscous zones. Gravity zone was obtained from 3.8 ± 0.43 s to 38.97 ± 3.38 s and from 5.99 ± 0.5 s to 77.82 ± 8.84 s for the Sn-2.5Ag-0.5Cu/Cu and Sn-2.5Ag-0.5Cu/Ni/Cu system, respectively. Sn-2.5Ag-0.5Cu solder alloy was also reflowed for the period corresponding to the end of the gravity zone (40 s and 80 s on bare and Ni-coated Cu, respectively). The joint strength was maximum at reflow time of 40 s and 80 s for the Sn-2.5Ag-0.5Cu/Cu and Sn-2.5Ag-0.5Cu/Ni/Cu system, respectively. The dynamic contact angle at the end of the gravity (diffusion) zone ( θ gz) was found to be a better parameter compared with the stabilized contact angle ( θ f) to assess the effect of the wettability of the liquid solder on the microstructure and joint strength. The present investigation reveals the significance of the gravity zone in assessment of optimum reflow time for lead-free solder alloys.

  1. Evaluation of the Sequential Spot Sampler (S3) for time-resolved measurement of PM2.5 sulfate and nitrate through lab and field measurements

    NASA Astrophysics Data System (ADS)

    Hecobian, A.; Evanoski-Cole, A.; Eiguren-Fernandez, A.; Sullivan, A. P.; Lewis, G. S.; Hering, S. V.; Collett, J. L., Jr.

    2016-02-01

    The Sequential Spot Sampler (S3), a newly developed instrument to collect aerosols for time-resolved chemical composition measurements, was evaluated in the laboratory and field for the measurement of particulate sulfate and nitrate. The S3 uses a multi-temperature condensation growth tube to grow individual aerosols to droplets which are then deposited as a ˜ 1 mm diameter dry spot at the end of the growth tube in a 100 µL well of a multi-well plate. The well plate advances automatically to provide a sequence of time-resolved samples. The collected aerosols are subsequently analyzed in the laboratory. The sample is concentrated during the collection process, and the laboratory extraction and analysis steps can be automated. The well plate, as received from the field, is placed onto a needle-based autosampler that adds liquid for sample extraction and injects sample extract from each well onto an ion chromatograph for analysis. Laboratory evaluation for sulfate and nitrate ions showed that poly ether ether ketone (PEEK) used as well plate material does not contribute any artifacts; a 60 min extraction procedure leads to the recovery of sulfate and nitrate from the dry spots at above 95 % extraction efficiency; and samples stored frozen and analyzed up to 23 months later show less than a 10 % change in sulfate and nitrate concentrations. The limit of detection was 0.5 µg m-3 for sulfate and 0.2 µg m-3 for nitrate for a 1 h sampling period. In a month-long field study conducted in southern California, two S3s were deployed alongside a URG denuder-filter-pack and a Particle-Into-Liquid Sampler combined with an Ion Chromatograph (PILS-IC). Collocated S3 sampler concentrations compared by linear regression show good agreement, with r2 = 0.99 and slope = 0.99 (±0.004) µg m-3 for sulfate and r2 = 0.99 and slope = 1.0 (±0.006) µg m-3 for nitrate. When compared to the URG denuder-filter-pack and the PILS-IC, the S3 sulfate and nitrate concentrations yielded

  2. Evaluation of a Sequential Spot Sampler (S3) for time-resolved measurement of PM2.5 sulfate and nitrate through lab and field measurements

    NASA Astrophysics Data System (ADS)

    Hecobian, A.; Evanoski-Cole, A.; Eiguren-Fernandez, A.; Sullivan, A. P.; Lewis, G. S.; Hering, S. V.; Collett, J. L., Jr.

    2015-10-01

    The Sequential Spot Sampler (S3), a newly developed instrument to collect aerosols for time resolved chemical composition measurements, was evaluated in the laboratory and field for the measurement of particulate sulfate and nitrate. The S3 uses a multi-temperature condensation growth tube to grow individual aerosols to droplets which are then deposited as a ~ 1 mm diameter dry spot at the end of the growth tube on a 100 μL well of a multi-well plate. The well plate advances automatically to provide a sequence of time-resolved samples. The collected aerosols are subsequently analyzed in the laboratory. The sample is concentrated during the collection process and the laboratory extraction and analysis steps can be automated. The well plate, as received from the field, is placed onto a needle-based autosampler that adds liquid for sample extraction and injects sample extract from each well onto an ion chromatograph for analysis. Laboratory evaluation for sulfate and nitrate ions showed that PEEK used as well plate material does not contribute any artifacts; a 60 min extraction procedure leads to the recovery of sulfate and nitrate from the dry spots at above 95 % extraction efficiency; and samples stored frozen and analyzed up to 23 months later show less than a 10 % change in sulfate and nitrate concentrations. In a month long field study conducted in Southern California, two S3s were deployed alongside a URG denuder/filter-pack and a Particle-Into-Liquid Sampler combined with an Ion Chromatograph (PILS-IC). Collocated S3 sampler concentrations compared by linear regression show good agreement with r2 = 0.99 and slope = 0.99 (±0.004) μg m-3 for sulfate and r2 = 0.99 and slope =1.0 (±0.006) μg m-3 for nitrate. When compared to the URG denuder/filter-pack and the PILS-IC, the S3 sulfate and nitrate concentrations yielded correlations above 0.84 for the square of the correlation coefficient and regression slopes close to one.

  3. Identifying Optimal Temporal Scale for the Correlation of AOD and Ground Measurements of PM2.5 to Improve the Model Performance in a Real-time Air Quality Estimation System

    NASA Technical Reports Server (NTRS)

    Li, Hui; Faruque, Fazlay; Williams, Worth; Al-Hamdan, Mohammad; Luvall, Jeffrey C.; Crosson, William; Rickman, Douglas; Limaye, Ashutosh

    2009-01-01

    Aerosol optical depth (AOD), an indirect estimate of particle matter using satellite observations, has shown great promise in improving estimates of PM 2.5 air quality surface. Currently, few studies have been conducted to explore the optimal way to apply AOD data to improve the model accuracy of PM 2.5 surface estimation in a real-time air quality system. We believe that two major aspects may be worthy of consideration in that area: 1) the approach to integrate satellite measurements with ground measurements in the pollution estimation, and 2) identification of an optimal temporal scale to calculate the correlation of AOD and ground measurements. This paper is focused on the second aspect on the identifying the optimal temporal scale to correlate AOD with PM2.5. Five following different temporal scales were chosen to evaluate their impact on the model performance: 1) within the last 3 days, 2) within the last 10 days, 3) within the last 30 days, 4) within the last 90 days, and 5) the time period with the highest correlation in a year. The model performance is evaluated for its accuracy, bias, and errors based on the following selected statistics: the Mean Bias, the Normalized Mean Bias, the Root Mean Square Error, Normalized Mean Error, and the Index of Agreement. This research shows that the model with the temporal scale of within the last 30 days displays the best model performance in this study area using 2004 and 2005 data sets.

  4. Time Work by Overworked Professionals: Strategies in Response to the Stress of Higher Status.

    PubMed

    Moen, Phyllis; Lam, Jack; Ammons, Samantha; Kelly, Erin L

    2013-05-01

    How are professionals responding to the time strains brought on by the stress of their higher status jobs? Qualitative data from professionals reveal (a) general acceptance of the emerging temporal organization of professional work, including rising time demands and blurred boundaries around work/ nonwork times and places, and (b) time work as strategic responses to work intensification, overloads, and boundarylessness. We detected four time-work strategies: prioritizing time, scaling back obligations, blocking out time, and time shifting of obligations. These strategies are often more work-friendly than family-friendly, but "blocking out time" and "time shifting" suggest promising avenues for work-time policy and practice. PMID:24039337

  5. State Spending on Higher Education: Testing the Balance Wheel over Time

    ERIC Educational Resources Information Center

    Delaney, Jennifer A.; Doyle, William R.

    2011-01-01

    This article considers the role of higher education in state budgets. It empirically models and tests the balance wheel hypothesis in a robust framework. The balance wheel model posits that in good economic times, higher education is an attractive area for states to fund and tends to be funded at a higher rate than other state budget categories.…

  6. Part-Time Higher Education in English Colleges: Adult Identities in Diminishing Spaces

    ERIC Educational Resources Information Center

    Esmond, Bill

    2015-01-01

    Adult participation in higher education has frequently entailed mature students studying part time in lower-ranked institutions. In England, higher education policies have increasingly emphasised higher education provision in vocational further education colleges, settings which have extensive adult traditions but which mainly teach…

  7. Changing Times of Feminism and Higher Education: From Community to Employability

    ERIC Educational Resources Information Center

    Moss, Dorothy; Richter, Ingrid

    2011-01-01

    This article discusses the creation of space and time for feminist approaches in higher education in the context of shifting community and employment relations and the restructuring of higher education space-time. It draws on the reflections of three feminist academics concerning aspects of their work biographies in two very different higher…

  8. Time as the Fourth Dimension in the Globalization of Higher Education

    ERIC Educational Resources Information Center

    Walker, Judith

    2009-01-01

    This paper calls for an analysis of time to be integrated into the theories on the globalization of higher education. Specifically, the author argues that academic capitalism, fuelled by globalization, has led to changes in the university visible in time/space compression, time acceleration, the reification of time and our internalization of the…

  9. The Legal Rights of Tenured and Part-Time Faculty Members in Higher Education.

    ERIC Educational Resources Information Center

    Corley, Sherie P.

    A review of faculty-related court decisions in the areas of status, compensation, and unit determination points out legal rights of part-time and full-time faculty in higher education. These rights have been tested and defined by many court cases. Litigation has occurred about the difference between part-time and full-time faculty. In regard to…

  10. The Benefits of Part-Time Undergraduate Study and UK Higher Education Policy: A Literature Review

    ERIC Educational Resources Information Center

    Bennion, Alice; Scesa, Anna; Williams, Ruth

    2011-01-01

    Part-time study in the UK is significant: nearly 40 per cent of higher education students study part-time. This article reports on a literature review that sought to understand the economic and social benefits of part-time study in the UK. It concludes that there are substantial and wide-ranging benefits from studying part-time. The article also…

  11. Pulse transmission receiver with higher-order time derivative pulse correlator

    DOEpatents

    Dress, Jr., William B.; Smith, Stephen F.

    2003-09-16

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission receiver includes: a higher-order time derivative pulse correlator; a demodulation decoder coupled to the higher-order time derivative pulse correlator; a clock coupled to the demodulation decoder; and a pseudorandom polynomial generator coupled to both the higher-order time derivative pulse correlator and the clock. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  12. Higher Education Students in Part-Time Work in a Chinese City

    ERIC Educational Resources Information Center

    Morrison, Keith

    2009-01-01

    This article discusses students taking part-time work whilst studying higher education (HE). It suggests that cross-national trends can be observed in the purposes, types, benefits, negative aspects and outcomes of part-time work by HE students. The paper reviews literature on HE students working part-time in the UK and the US, and UNESCO studies…

  13. Time Work by Overworked Professionals: Strategies in Response to the Stress of Higher Status

    PubMed Central

    Moen, Phyllis; Lam, Jack; Ammons, Samantha; Kelly, Erin L.

    2013-01-01

    How are professionals responding to the time strains brought on by the stress of their higher status jobs? Qualitative data from professionals reveal (a) general acceptance of the emerging temporal organization of professional work, including rising time demands and blurred boundaries around work/ nonwork times and places, and (b) time work as strategic responses to work intensification, overloads, and boundarylessness. We detected four time-work strategies: prioritizing time, scaling back obligations, blocking out time, and time shifting of obligations. These strategies are often more work-friendly than family-friendly, but “blocking out time” and “time shifting” suggest promising avenues for work-time policy and practice. PMID:24039337

  14. Part-time Faculty Job Satisfaction in Higher Education: A Literature Review

    ERIC Educational Resources Information Center

    Howell, Scott L.; Hoyt, Jeff

    2007-01-01

    The purpose of this literature review was to inform researchers of those predictive factors of job satisfaction previously identified for part-time faculty in higher education. They used the information gathered to help develop a survey instrument that was administered to 700 part-time faculty at their own institution. The results of the study,…

  15. Preparation and Support for Part-Time Teachers in Higher Education: Case Studies of Departmental Practice.

    ERIC Educational Resources Information Center

    Forster, Fred, Comp.; Thompson, Sheila, Comp.

    This publication presents 14 departmental case studies of the preparation and support provided to part-time teachers in Scottish institutions of higher education. The case studies are grouped in four sections according to the category of part-time staff involved: practicing professionals (professional teaching assistants, lawyers, artists, and…

  16. The Motivations and Outcomes of Studying for Part-Time Mature Students in Higher Education

    ERIC Educational Resources Information Center

    Swain, Jon; Hammond, Cathie

    2011-01-01

    This paper examines the motivations and outcomes for mature students who study part-time in higher education (HE) in the UK. Although many students in HE are mature part-time learners, they have not been the specific focus of much research or policy interest. In-depth narrative interviews were carried out with 18 graduates who had studied…

  17. The Supply of Part-Time Higher Education in the UK. Research Report

    ERIC Educational Resources Information Center

    Callender, Claire; Birkbeck, Anne Jamieson; Mason, Geoff

    2010-01-01

    This report explores the supply of part-time higher education in the UK, with particular consideration to the study of part-time undergraduate provision in England. It is the final publication in the series of reports on individual student markets that were commissioned by Universities UK following the publication of the reports on the Future size…

  18. Population Exposure to PM2.5 in the Urban Area of Beijing

    PubMed Central

    Zhang, An; Qi, Qingwen; Jiang, Lili; Zhou, Fang; Wang, Jinfeng

    2013-01-01

    The air quality in Beijing, especially its PM2.5 level, has become of increasing public concern because of its importance and sensitivity related to health risks. A set of monitored PM2.5 data from 31 stations, released for the first time by the Beijing Environmental Protection Bureau, covering 37 days during autumn 2012, was processed using spatial interpolation and overlay analysis. Following analyses of these data, a distribution map of cumulative exceedance days of PM2.5 and a temporal variation map of PM2.5 for Beijing have been drawn. Computational and analytical results show periodic and directional trends of PM2.5 spreading and congregating in space, which reveals the regulation of PM2.5 overexposure on a discontinuous medium-term scale. With regard to the cumulative effect of PM2.5 on the human body, the harm from lower intensity overexposure in the medium term, and higher overexposure in the short term, are both obvious. Therefore, data of population distribution were integrated into the aforementioned PM2.5 spatial spectrum map. A spatial statistical analysis revealed the patterns of PM2.5 gross exposure and exposure probability of residents in the Beijing urban area. The methods and conclusions of this research reveal relationships between long-term overexposure to PM2.5 and people living in high-exposure areas of Beijing, during the autumn of 2012. PMID:23658832

  19. Finite time control for MIMO nonlinear system based on higher-order sliding mode.

    PubMed

    Liu, Xiangjie; Han, Yaozhen

    2014-11-01

    Considering a class of MIMO uncertain nonlinear system, a novel finite time stable control algorithm is proposed based on higher-order sliding mode concept. The higher-order sliding mode control problem of MIMO nonlinear system is firstly transformed into finite time stability problem of multivariable system. Then continuous control law, which can guarantee finite time stabilization of nominal integral chain system, is employed. The second-order sliding mode is used to overcome the system uncertainties. High frequency chattering phenomenon of sliding mode is greatly weakened, and the arbitrarily fast convergence is reached. The finite time stability is proved based on the quadratic form Lyapunov function. Examples concerning the triple integral chain system with uncertainty and the hovercraft trajectory tracking are simulated respectively to verify the effectiveness and the robustness of the proposed algorithm. PMID:25277626

  20. Finite time control for MIMO nonlinear system based on higher-order sliding mode.

    PubMed

    Liu, Xiangjie; Han, Yaozhen

    2014-11-01

    Considering a class of MIMO uncertain nonlinear system, a novel finite time stable control algorithm is proposed based on higher-order sliding mode concept. The higher-order sliding mode control problem of MIMO nonlinear system is firstly transformed into finite time stability problem of multivariable system. Then continuous control law, which can guarantee finite time stabilization of nominal integral chain system, is employed. The second-order sliding mode is used to overcome the system uncertainties. High frequency chattering phenomenon of sliding mode is greatly weakened, and the arbitrarily fast convergence is reached. The finite time stability is proved based on the quadratic form Lyapunov function. Examples concerning the triple integral chain system with uncertainty and the hovercraft trajectory tracking are simulated respectively to verify the effectiveness and the robustness of the proposed algorithm.

  1. Higher-Order, Space-Time Adaptive Finite Volume Methods: Algorithms, Analysis and Applications

    SciTech Connect

    Minion, Michael

    2014-04-29

    The four main goals outlined in the proposal for this project were: 1. Investigate the use of higher-order (in space and time) finite-volume methods for fluid flow problems. 2. Explore the embedding of iterative temporal methods within traditional block-structured AMR algorithms. 3. Develop parallel in time methods for ODEs and PDEs. 4. Work collaboratively with the Center for Computational Sciences and Engineering (CCSE) at Lawrence Berkeley National Lab towards incorporating new algorithms within existing DOE application codes.

  2. An efficient higher-order PML in WLP-FDTD method for time reversed wave simulation

    NASA Astrophysics Data System (ADS)

    Wei, Xiao-Kun; Shao, Wei; Ou, Haiyan; Wang, Bing-Zhong

    2016-09-01

    Derived from a stretched coordinate formulation, a higher-order complex frequency shifted (CFS) perfectly matched layer (PML) is proposed for the unconditionally stable finite-difference time-domain (FDTD) method based on weighted Laguerre polynomials (WLPs). The higher-order PML is implemented with an auxiliary differential equation (ADE) approach. In order to further improve absorbing performance, the parameter values of stretching functions in the higher-order PML are optimized by the multi-objective genetic algorithm (MOGA). The optimal solutions can be chosen from the Pareto front for trading-off between two independent objectives. It is shown in a numerical test that the higher-order PML is efficient in terms of attenuating propagating waves and reducing late time reflections. Moreover, the higher-order PML can be placed very close to the wall when analyzing the channel characteristics of time reversal (TR) waves in a multipath indoor environment. Numerical examples of TR wave propagation demonstrate the availability of the proposed method.

  3. Iterative generation of higher-order nets in polynomial time using linear programming.

    PubMed

    Roy, A; Mukhopadhyay, S

    1997-01-01

    This paper presents an algorithm for constructing and training a class of higher-order perceptrons for classification problems. The method uses linear programming models to construct and train the net. Its polynomial time complexity is proven and computational results are provided for several well-known problems. In all cases, very small nets were created compared to those reported in other computational studies.

  4. Curriculum Characteristics of Time-Compressed Course in a U.S. Higher Education Institution

    ERIC Educational Resources Information Center

    Hyun, Eunsook; Kretovics, Mark; Crowe, Alicia

    2006-01-01

    The study explored characteristics of the curriculum practice of higher education faculty in the context of time-compressed (e.g., 5-6 weeks) courses as compared with regular term (15-16 weeks) courses. The researchers used open-ended questions on a web-based survey at a large doctoral-extensive university in a Midwestern state in the United…

  5. "Times Higher Education" 100 under 50 Ranking: Old Wine in a New Bottle?

    ERIC Educational Resources Information Center

    Soh, Kaycheng

    2013-01-01

    "Times Higher Education" 100 under 50 ranking is a new twist to the university ranking. It focuses on universities that have a history of 50 years or less with the purpose of offsetting the advantage of prestige of the older ones. This article re-analysed the data publicly available and looked into relevant conceptual and statistical issues. The…

  6. Analyzing the Anglo-American Hegemony in the "Times Higher Education" Rankings

    ERIC Educational Resources Information Center

    Kaba, Amadu Jacky

    2012-01-01

    This study analyzes the 2009 "Times Higher Education"-QS top 200 universities in the world. Based on this analysis the study claims that the THS reflects the phenomenon of Anglo American hegemony. The United States with 54 universities and the United Kingdom with 29 dominated the THS. In addition, six out of every ten universities on the top 200…

  7. A time-saving method for higher plant tests in hydroculture.

    PubMed

    Andersohn, Cornelia; Fuchs, Maike; Seyed-Mansouri, Regina; Fleischmann, Susanne; Wilke, Berndt-Michael

    2002-01-01

    For higher plant tests in hydroculture we developed a method to unify the usually separately performed germination and growth testing. This method renders unnecessary the time-consuming and laborious installation of the germinated plants into the growth system. PMID:11931464

  8. Institutional View of Part-Time Faculty Management in Higher Education Institutes in China

    ERIC Educational Resources Information Center

    Li, Zhifeng; Jiang, Xiulan; Li, Hongbo

    2007-01-01

    Part-time faculty has become an important labor force in Chinese colleges and universities. The number of them has risen rapidly and its structure varies in different types of higher education institutes (HEIs), which results from integration of the social motivation and the inner motivation of schools' reform. From the institutional point of…

  9. Source apportionment of PM2.5 in Incheon, Korea

    NASA Astrophysics Data System (ADS)

    Choi, J.; Ban, S.; Lee, C.; Yi, S.; Zoh, K.

    2011-12-01

    PM2.5 samples were collected at a centrally located urban monitoring site in Incheon, Korea, every third day from Jun 2009 to may 2010 and analyzed their chemical species. In this study, we investigated the source of PM2.5 using Positive Matrix Factorization(PMF), the source area from Potential Source Contribution Function (PSCF) and Conditional Probability Function(CPF), and characterized source variation among episode, non-episode, yellow sand events. Incheon, study site, is located at the mid-western tip of the Korean Peninsula with a population of 2.6 million people and area of 1029.4 km2, respectively. As a transportation hub, the city also holds the importance of meteological/geological aspect affecting the air quality of capital region, in that is prevailing westerlies zone and a air passageway from China to Japan passing through seoul, korea. In the study, the Four channel based on Annular Denuder System(ADS) were used for sample collection(URG co, USA). The filter samples were analyzed with respect to species type such as ion group, metal, and OC/EC compound using ion chromatography, ICP/MS, and NIOSH TOT method, respectively. The PM2.5 concentration was 43ug/m3 that is almost three times higher than the US NAAQS annual PM2.5 standard of 15ug/m3. Nine PM2.5 sources were resolved from PMF analysis that provided reasonable source profiles and interesting insights into the source contributions to the ambient mass concentrations. The major sources of PM2.5 were secondary nitrate(26.4%), secondary sulfate(17.3%), gasoline(16.4%), and residual oil combustion(13.5%), with lesser contributions from biomass burning (7.5%), road dust(6.9%), soil (5.5%), coal fire powerplant (4.0%), and free sea salt(2.4%). CPF results identified possible local source directions such as motor vehicles, free sea salt. PSCF results indicated that likely pollution areas increased secondary particle concentrations(sulfate and nitrate) in Incheon to be the major industrial areas in China

  10. American Higher Education in 1975 and 1976: The Academy's Response to Continuing Kondratieff Recession as Reported in "The Times Higher Education Supplement" (London).

    ERIC Educational Resources Information Center

    Hawley, John B.; And Others

    Articles on American higher education that appeared in 1975 and 1976 in "The Times Higher Education Supplement" (London) are analyzed in connection with two statements about American society and its economy. These statements are Joseph A. Schumpeter's 1939 analysis of business cycles, and James B. Shuman's and Davis Rosenau's 1972 description of…

  11. OBSERVABLE INDICATORS OF THE SENSITIVITY OF PM2.5 NITRATE TO EMISSION REDUCTIONS PART I: DERIVATION OF THE ADJUSTED GAS RATIO AND APPLICABILITY AT REGULATORY-RELEVANT TIME SCALES

    EPA Science Inventory

    Chemical transport models have frequently been used to evaluate the impacts of emission reductions on inorganic PM2.5. However, such models are limited in their accuracy by uncertain estimates of the spatial and temporal characterization of emissions and meteorology. Site-speci...

  12. The Internet Time Lag: Anticipating the Long-Term Consequences of the Information Revolution. A Report of the Annual Aspen Institute Roundtable on Information Technology (10th, Aspen, Colorado, August 2-5, 2001).

    ERIC Educational Resources Information Center

    Schwartz, Evan I.

    This is a report of the 10th annual Aspen Institute Roundtable on Information Technology (Aspen, Colorado, August 2-5, 2001). Participants were also polled after the events of September 11, and these comments have been integrated into the report. The mission of this report is to take a wide-ranging look at the trends that are defining the next new…

  13. Higher-order brick-tetrahedron hybrid method for Maxwell's equations in time domain

    NASA Astrophysics Data System (ADS)

    Winges, Johan; Rylander, Thomas

    2016-09-01

    We present a higher-order brick-tetrahedron hybrid method for Maxwell's equations in time domain. Brick-shaped elements are used for large homogeneous parts of the computational domain, where we exploit mass-lumping and explicit time-stepping. In regions with complex geometry, we use an unstructured mesh of tetrahedrons that share an interface with the brick-shaped elements and, at the interface, tangential continuity of the electric field is imposed in the weak sense by means of Nitsche's method. Implicit time-stepping is used for the tetrahedrons together with the interface. For cavity resonators, the hybrid method reproduces the lowest non-zero eigenvalues with correct multiplicity and, for geometries without field singularities from sharp corners or edges, the numerical eigenvalues converge towards the analytical result with an error that is approximately proportional to h2p, where h is the cell size and p is the polynomial order of the elements. For a rectangular waveguide, a layer of tetrahedrons embedded in a grid of brick-shaped elements yields a low reflection coefficient that scales approximately as h2p. Finally, we demonstrate hybrid time-stepping for a lossless closed cavity resonator, where the time-domain response is computed for 300,000 time steps without any signs of instabilities.

  14. Identification of potential source areas for elevated PM2.5, nitrate and sulfate concentrations

    NASA Astrophysics Data System (ADS)

    Heo, Jongbae; McGinnis, Jerome E.; de Foy, Benjamin; Schauer, James J.

    2013-06-01

    Extreme events or episodes of ambient fine particulate matter (PM2.5), in which daily mass concentrations are substantially higher than annual averages, have been frequently observed in southern Wisconsin, US. Determining the cause of events has been a great challenge to local governments responsible for protecting public health and complying with the 24-h PM2.5 standard. This study analyzed air parcel movements originating from emission source areas, and trends in PM2.5 concentrations in order to determine the important factors involved in elevated PM2.5 episodes in the region. A single backward trajectory analysis coupled with PM2.5 concentrations observed at Federal Reference Method Network (FRM) sites in Madison, Milwaukee and Waukesha; and nitrate and sulfate concentrations monitored at a Chemical Speciation Network (CSN) site in Milwaukee, Wisconsin, from 2002 to 2010 were examined. The PM2.5 concentrations from the FRM showed the total PM2.5 mass during the episodes were higher in Madison than in Milwaukee and Waukesha, while annual average concentrations were lower in Madison. However, the temporal trend in frequency of elevated PM2.5 episodes was remarkably similar across sites during the entire study period and high frequency episodes occurring from 2005 to 2007. Residence time analysis of backward trajectories calculated for all recorded data indicated episode changes were mainly driven by year-to-year variations of air mass movements originating in high emissions areas. Potential Source Contribution Function (PSCF) results showed the extreme events of PM2.5 occurred during times when trajectories passed over ammonia emissions hotspots as well as large stationary emissions. Enhanced nitrate and sulfate concentrations which were the major episode components were strongly influenced by air masses trajectories originating from the Ohio River Valley and adjacent states.

  15. Time-domain multimode dispersion measurement in a higher-order-mode fiber

    PubMed Central

    Cheng, Ji; Pedersen, Martin E. V.; Wang, Ke; Xu, Chris; Grüner-Nielsen, Lars; Jakobsen, Dan

    2012-01-01

    We present a new multimode dispersion measurement technique based on the time-of-flight method. The modal delay and group velocity dispersion of all excited modes in a few-mode fiber can be measured simultaneously by a tunable pulsed laser and a high speed sampling oscilloscope. A newly designed higher-order-mode fiber with large anomalous dispersion in the LP02 mode has been characterized using this method, and experimental results are in good agreement with the designed dispersion values. The demonstrated technique is significantly simpler to implement than the existing frequency-domain or interferometry-based methods. PMID:22297348

  16. Wavelet Transform Based Higher Order Statistical Analysis of Wind and Wave Time Histories

    NASA Astrophysics Data System (ADS)

    Habib Huseni, Gulamhusenwala; Balaji, Ramakrishnan

    2016-06-01

    Wind, blowing on the surface of the ocean, imparts the energy to generate the waves. Understanding the wind-wave interactions is essential for an oceanographer. This study involves higher order spectral analyses of wind speeds and significant wave height time histories, extracted from European Centre for Medium-Range Weather Forecast database at an offshore location off Mumbai coast, through continuous wavelet transform. The time histories were divided by the seasons; pre-monsoon, monsoon, post-monsoon and winter and the analysis were carried out to the individual data sets, to assess the effect of various seasons on the wind-wave interactions. The analysis revealed that the frequency coupling of wind speeds and wave heights of various seasons. The details of data, analysing technique and results are presented in this paper.

  17. Discrete sliding mode control for robust tracking of higher order delay time systems with experimental application.

    PubMed

    Khandekar, A A; Malwatkar, G M; Patre, B M

    2013-01-01

    In this paper, a discrete time sliding mode controller (DSMC) is proposed for higher order plus delay time (HOPDT) processes. A sliding mode surface is selected as a function of system states and error and the tuning parameters of sliding mode controller are determined using dominant pole placement strategy. The condition for the existence of stable sliding mode is obtained by using Lyapunov function. The proposed method is applicable to HOPDT processes with oscillatory and integrating behavior, open loop instability or non-minimum phase characteristics and works satisfactory under the effect of parametric uncertainty. The method does not require reduced order model and provides simple way to design the controllers. The simulation and experimentation results show that the proposed method ensures desired tracking dynamics.

  18. Higher Order Time Integration Schemes for the Unsteady Navier-Stokes Equations on Unstructured Meshes

    NASA Technical Reports Server (NTRS)

    Jothiprasad, Giridhar; Mavriplis, Dimitri J.; Caughey, David A.; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    The efficiency gains obtained using higher-order implicit Runge-Kutta schemes as compared with the second-order accurate backward difference schemes for the unsteady Navier-Stokes equations are investigated. Three different algorithms for solving the nonlinear system of equations arising at each timestep are presented. The first algorithm (NMG) is a pseudo-time-stepping scheme which employs a non-linear full approximation storage (FAS) agglomeration multigrid method to accelerate convergence. The other two algorithms are based on Inexact Newton's methods. The linear system arising at each Newton step is solved using iterative/Krylov techniques and left preconditioning is used to accelerate convergence of the linear solvers. One of the methods (LMG) uses Richardson's iterative scheme for solving the linear system at each Newton step while the other (PGMRES) uses the Generalized Minimal Residual method. Results demonstrating the relative superiority of these Newton's methods based schemes are presented. Efficiency gains as high as 10 are obtained by combining the higher-order time integration schemes with the more efficient nonlinear solvers.

  19. Higher Order Time Integration Schemes for the Unsteady Navier-Stokes Equations on Unstructured Meshes

    NASA Technical Reports Server (NTRS)

    Jothiprasad, Giridhar; Mavriplis, Dimitri J.; Caughey, David A.

    2002-01-01

    The rapid increase in available computational power over the last decade has enabled higher resolution flow simulations and more widespread use of unstructured grid methods for complex geometries. While much of this effort has been focused on steady-state calculations in the aerodynamics community, the need to accurately predict off-design conditions, which may involve substantial amounts of flow separation, points to the need to efficiently simulate unsteady flow fields. Accurate unsteady flow simulations can easily require several orders of magnitude more computational effort than a corresponding steady-state simulation. For this reason, techniques for improving the efficiency of unsteady flow simulations are required in order to make such calculations feasible in the foreseeable future. The purpose of this work is to investigate possible reductions in computer time due to the choice of an efficient time-integration scheme from a series of schemes differing in the order of time-accuracy, and by the use of more efficient techniques to solve the nonlinear equations which arise while using implicit time-integration schemes. This investigation is carried out in the context of a two-dimensional unstructured mesh laminar Navier-Stokes solver.

  20. Endotoxin in fine (PM 2.5) and coarse (PM 2.5-10) particle mass of ambient aerosols. A temporo-spatial analysis

    NASA Astrophysics Data System (ADS)

    Heinrich, Joachim; Pitz, Mike; Bischof, Wolfgang; Krug, Norbert; Borm, Paul J. A.

    Objectives: We collected fine (PM 2.5) and coarse (PM 2.5-10) particulate matter fractions in two areas ˜80 km apart and measured soluble endotoxin concentrations in both particle fractions. Here we report on temporo-spatial variation of endotoxin content in the collected particles. Methods: Dichotomous Anderson samplers were used to collect 21 weekly samples of PM 2.5 and PM 2.5-10 in both towns from January to June 2002. Each Teflon filter was water extracted and endotoxin was measured by a chromogenic Limulus Amoebocyte Lysate method. Endotoxin concentrations were expressed per mg of fine or mg of coarse mass and per sampled air volume (m 3). Results: For both cities, the mean endotoxin content in PM 2.5 was 1.2 EU mg -1; however the endotoxin content in the coarse fraction was ˜10 times higher compared to the fine mass fractions. Although endotoxin content is highly variable over time, a good correlation was observed between the two town sites for both fine ( r=0.85) and coarse PM ( r=0.88). The fluctuations of weekly endotoxin means were high in both areas suggesting a strong temporal dependence on particle source and composition. The endotoxin content in particles collected during May and June were two to four times higher than concentrations measured during the winter and early spring weeks. Conclusions: Ambient airborne endotoxin concentrations were detected in coarse and fine particle fraction, but 10-fold higher in the coarse PM. The strong seasonality and the week to week fluctuation of endotoxin content in PM indicate different biologic PM properties which might affect results of time series studies on short-term effects as well as in vitro studies and human exposure studies.

  1. 12 CFR 2.5 - Bank compensation.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Bank compensation. 2.5 Section 2.5 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY SALES OF CREDIT LIFE INSURANCE § 2.5 Bank compensation. (a) Nothing contained in this part prohibits a bank employee, officer, director, or...

  2. 12 CFR 2.5 - Bank compensation.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Bank compensation. 2.5 Section 2.5 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY SALES OF CREDIT LIFE INSURANCE § 2.5 Bank compensation. (a) Nothing contained in this part prohibits a bank employee, officer, director, or...

  3. 12 CFR 2.5 - Bank compensation.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Bank compensation. 2.5 Section 2.5 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY SALES OF CREDIT LIFE INSURANCE § 2.5 Bank compensation. (a) Nothing contained in this part prohibits a bank employee, officer, director, or...

  4. 12 CFR 2.5 - Bank compensation.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 1 2011-01-01 2011-01-01 false Bank compensation. 2.5 Section 2.5 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY SALES OF CREDIT LIFE INSURANCE § 2.5 Bank compensation. (a) Nothing contained in this part prohibits a bank employee, officer, director, or...

  5. 28 CFR 2.5 - Sentence aggregation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Sentence aggregation. 2.5 Section 2.5 Judicial Administration DEPARTMENT OF JUSTICE PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS, YOUTH OFFENDERS, AND JUVENILE DELINQUENTS United States Code Prisoners and Parolees § 2.5...

  6. Pulse transmission receiver with higher-order time derivative pulse generator

    DOEpatents

    Dress, Jr., William B.; Smith, Stephen F.

    2003-08-12

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission receiver includes: a front-end amplification/processing circuit; a synchronization circuit coupled to the front-end amplification/processing circuit; a clock coupled to the synchronization circuit; a trigger signal generator coupled to the clock; and at least one higher-order time derivative pulse generator coupled to the trigger signal generator. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  7. Numerical time dependent sheet cavitation simulations using a higher order panel method

    NASA Astrophysics Data System (ADS)

    Dekoninggans, H. J.

    1994-03-01

    This thesis deals with sheet cavitation. The investigation is aimed at profile design with respect to cavitation control. At present it is possible to predict the shape of cavities on an arbitrary two-dimensional profile in stationary flows. To compute the flow around an arbitrary profile, a higher order three-dimensional panel method program has been developed. The main algorithm used in this program is based on a special case of Green's theorem, called 'de Morino formulation'. This computer program (flow program) can calculate the potential on the body and the velocities at the surface of the body or in the flow field. A theoretical method is developed for time simulation of unsteady sheet cavitation. Numerical simulations of the flow around profiles and of cavitation have been carried out. The numerical results of the panel methods have been compared with other calculations of the two-dimensional flow around profiles and of three-dimensional flow around a sphere and a wing. Simulations of the growth of sheet cavitation on a foil have also been carried out. The conclusion is that higher order panel methods are more accurate than the zero order methods. Further refinement of the Kutta condition is required, however.

  8. Fine particulate matter (PM2.5) in China at a city level

    PubMed Central

    Zhang, Yan-Lin; Cao, Fang

    2015-01-01

    This study presents one of the first long term datasets including a statistical summary of PM2.5 concentrations obtained from one-year monitoring in 190 cities in China. We found only 25 out of 190 cities could meet the National Ambient Air Quality Standards of China, and the population-weighted mean of PM2.5 in Chinese cities are 61 μg/m3, ~3 times as high as global population-weighted mean, highlighting a high health risk. PM2.5 concentrations are generally higher in north than in south regions due to relative large PM emissions and unfavorable meteorological conditions for pollution dispersion. A remarkable seasonal variability of PM2.5 is observed with the highest during the winter and the lowest during the summer. Due to the enhanced contributions from dust particles and open biomass burning, high PM2.5 abundances are also found in the spring (in Northwest and West Central China) and autumn (in East China), respectively. In addition, we found the lowest and highest PM2.5 often occurs in the afternoon and evening hours, respectively, associated with daily variation of the boundary layer depth and anthropogenic emissions. The diurnal distribution of the PM2.5-to-CO ratio consistently displays a pronounced peak during the afternoon periods, reflecting a significant contribution of secondary PM formation. PMID:26469995

  9. Fission Multiplicity Detection with Temporal Gamma-Neutron Discrimination from Higher-Order Time Correlation Statistics

    SciTech Connect

    Oberer, R.B.

    2002-11-12

    The current practice of nondestructive assay (NDA) of fissile materials using neutrons is dominated by the {sup 3}He detector. This has been the case since the mid 1980s when Fission Multiplicity Detection (FMD) was replaced with thermal well counters and neutron multiplicity counting (NMC). The thermal well counters detect neutrons by neutron capture in the {sup 3}He detector subsequent to moderation. The process of detection requires from 30 to 60 {micro}s. As will be explained in Section 3.3 the rate of detecting correlated neutrons (signal) from the same fission are independent of this time but the rate of accidental correlations (noise) are proportional to this time. The well counters are at a distinct disadvantage when there is a large source of uncorrelated neutrons present from ({alpha}, n) reactions for example. Plastic scintillating detectors, as were used in FMD, require only about 20 ns to detect neutrons from fission. One thousandth as many accidental coincidences are therefore accumulated. The major problem with the use of fast-plastic scintillation detectors, however, is that both neutrons and gamma rays are detected. The pulses from the two are indistinguishable in these detectors. For this thesis, a new technique was developed to use higher-order time correlation statistics to distinguish combinations of neutron and gamma ray detections in fast-plastic scintillation detectors. A system of analysis to describe these correlations was developed based on simple physical principles. Other sources of correlations from non-fission events are identified and integrated into the analysis developed for fission events. A number of ratios and metric are identified to determine physical properties of the source from the correlations. It is possible to determine both the quantity being measured and detection efficiency from these ratios from a single measurement without a separate calibration. To account for detector dead-time, an alternative analytical technique

  10. A novel fast gas chromatography method for higher time resolution measurements of speciated monoterpenes in air

    NASA Astrophysics Data System (ADS)

    Jones, C. E.; Kato, S.; Nakashima, Y.; Kajii, Y.

    2014-05-01

    Biogenic emissions supply the largest fraction of non-methane volatile organic compounds (VOC) from the biosphere to the atmospheric boundary layer, and typically comprise a complex mixture of reactive terpenes. Due to this chemical complexity, achieving comprehensive measurements of biogenic VOC (BVOC) in air within a satisfactory time resolution is analytically challenging. To address this, we have developed a novel, fully automated Fast Gas Chromatography (Fast-GC) based technique to provide higher time resolution monitoring of monoterpenes (and selected other C9-C15 terpenes) during plant emission studies and in ambient air. To our knowledge, this is the first study to apply a Fast-GC based separation technique to achieve quantification of terpenes in ambient air. Three chromatography methods have been developed for atmospheric terpene analysis under different sampling scenarios. Each method facilitates chromatographic separation of selected BVOC within a significantly reduced analysis time compared to conventional GC methods, whilst maintaining the ability to quantify individual monoterpene structural isomers. Using this approach, the C9-C15 BVOC composition of single plant emissions may be characterised within a 14.5 min analysis time. Moreover, in-situ quantification of 12 monoterpenes in unpolluted ambient air may be achieved within an 11.7 min chromatographic separation time (increasing to 19.7 min when simultaneous quantification of multiple oxygenated C9-C10 terpenoids is required, and/or when concentrations of anthropogenic VOC are significant). These analysis times potentially allow for a twofold to fivefold increase in measurement frequency compared to conventional GC methods. Here we outline the technical details and analytical capability of this chromatographic approach, and present the first in-situ Fast-GC observations of 6 monoterpenes and the oxygenated BVOC (OBVOC) linalool in ambient air. During this field deployment within a suburban forest

  11. Automated Determination of P-Wave Arrival Times Using Higher Order Statistics

    NASA Astrophysics Data System (ADS)

    Kueperkoch, L.; Meier, T.; Friederich, W.

    2009-04-01

    Due to the continuously increasing amount of digital, seismological data, automatic localication of seismic events becomes more and more important. The main difficulty is the automatic identification and precise determination of P- and S-wave arrival times. Here we present an algorithm based on higher order statistics for the automated determination of P-onsets of local and regional seismic events. Using the 4th central moment, a characteristic function is calculated, on which the "picker" is applied. Important is the automatic estimation of the quality of the P-onset. In order to get rid off false P-readings, several algorithms are applied to single station as well as to the finishing multy station processing. The robustness and reliability of the automatic has been tested on a very heterogeneous data set of the temporary, regional seismological network EGELADOS, using manual P-readings, which serve as reference picks, as well as by a comparison with the Allen- and the Baer- & Kradolfer-picker. The accuracy and the speed of the presented automatic makes this processing scheme to an option for the implementation into a near-real time processing, e.g. for earthquake early-warning systems.

  12. Effects on noise properties of GPS time series caused by higher-order ionospheric corrections

    NASA Astrophysics Data System (ADS)

    Jiang, Weiping; Deng, Liansheng; Li, Zhao; Zhou, Xiaohui; Liu, Hongfei

    2014-04-01

    Higher-order ionospheric (HOI) effects are one of the principal technique-specific error sources in precise global positioning system (GPS) analysis. These effects also influence the non-linear characteristics of GPS coordinate time series. In this paper, we investigate these effects on coordinate time series in terms of seasonal variations and noise amplitudes. Both power spectral techniques and maximum likelihood estimators (MLE) are used to evaluate these effects quantitatively and qualitatively. Our results show an overall improvement for the analysis of global sites if HOI effects are considered. We note that the noise spectral index that is used for the determination of the optimal noise models in our analysis ranged between -1 and 0 both with and without HOI corrections, implying that the coloured noise cannot be removed by these corrections. However, the corrections were found to have improved noise properties for global sites. After the corrections were applied, the noise amplitudes at most sites decreased, among which the white noise amplitudes decreased remarkably. The white noise amplitudes of up to 81.8% of the selected sites decreased in the up component, and the flicker noise of 67.5% of the sites decreased in the north component. Stacked periodogram results show that, no matter whether the HOI effects are considered or not, a common fundamental period of 1.04 cycles per year (cpy), together with the expected annual and semi-annual signals, can explain all peaks of the north and up components well. For the east component, however, reasonable results can be obtained only based on HOI corrections. HOI corrections are useful for better detecting the periodic signals in GPS coordinate time series. Moreover, the corrections contributed partly to the seasonal variations of the selected sites, especially for the up component. Statistically, HOI corrections reduced more than 50% and more than 65% of the annual and semi-annual amplitudes respectively at the

  13. Higher-order time integration of Coulomb collisions in a plasma using Langevin equations

    SciTech Connect

    Dimits, A.M.; Cohen, B.I.; Caflisch, R.E.; Rosin, M.S.; Ricketson, L.F.

    2013-06-01

    The extension of Langevin-equation Monte-Carlo algorithms for Coulomb collisions from the conventional Euler–Maruyama time integration to the next higher order of accuracy, the Milstein scheme, has been developed, implemented, and tested. This extension proceeds via a formulation of the angular scattering directly as stochastic differential equations in the fixed-frame spherical-coordinate velocity variables. Results from the numerical implementation show the expected improvement [O(Δt) vs. O(Δt{sup 1/2})] in the strong convergence rate both for the speed |v| and angular components of the scattering. An important result is that this improved convergence is achieved for the angular component of the scattering if and only if the “area-integral” terms in the Milstein scheme are included. The resulting Milstein scheme is of value as a step towards algorithms with both improved accuracy and efficiency. These include both algorithms with improved convergence in the averages (weak convergence) and multi-time-level schemes. The latter have been shown to give a greatly reduced cost for a given overall error level when compared with conventional Monte-Carlo schemes, and their performance is improved considerably when the Milstein algorithm is used for the underlying time advance versus the Euler–Maruyama algorithm. A new method for sampling the area integrals is given which is a simplification of an earlier direct method and which retains high accuracy. This method, while being useful in its own right because of its relative simplicity, is also expected to considerably reduce the computational requirements for the direct conditional sampling of the area integrals that is needed for adaptive strong integration.

  14. Higher-order time integration of Coulomb collisions in a plasma using Langevin equations

    SciTech Connect

    Dimits, A. M.; Cohen, B. I.; Caflisch, R. E.; Rosin, M. S.; Ricketson, L. F.

    2013-02-08

    The extension of Langevin-equation Monte-Carlo algorithms for Coulomb collisions from the conventional Euler-Maruyama time integration to the next higher order of accuracy, the Milstein scheme, has been developed, implemented, and tested. This extension proceeds via a formulation of the angular scattering directly as stochastic differential equations in the two fixed-frame spherical-coordinate velocity variables. Results from the numerical implementation show the expected improvement [O(Δt) vs. O(Δt1/2)] in the strong convergence rate both for the speed |v| and angular components of the scattering. An important result is that this improved convergence is achieved for the angular component of the scattering if and only if the “area-integral” terms in the Milstein scheme are included. The resulting Milstein scheme is of value as a step towards algorithms with both improved accuracy and efficiency. These include both algorithms with improved convergence in the averages (weak convergence) and multi-time-level schemes. The latter have been shown to give a greatly reduced cost for a given overall error level when compared with conventional Monte-Carlo schemes, and their performance is improved considerably when the Milstein algorithm is used for the underlying time advance versus the Euler-Maruyama algorithm. A new method for sampling the area integrals is given which is a simplification of an earlier direct method and which retains high accuracy. Lastly, this method, while being useful in its own right because of its relative simplicity, is also expected to considerably reduce the computational requirements for the direct conditional sampling of the area integrals that is needed for adaptive strong integration.

  15. Higher-order time integration of Coulomb collisions in a plasma using Langevin equations

    DOE PAGES

    Dimits, A. M.; Cohen, B. I.; Caflisch, R. E.; Rosin, M. S.; Ricketson, L. F.

    2013-02-08

    The extension of Langevin-equation Monte-Carlo algorithms for Coulomb collisions from the conventional Euler-Maruyama time integration to the next higher order of accuracy, the Milstein scheme, has been developed, implemented, and tested. This extension proceeds via a formulation of the angular scattering directly as stochastic differential equations in the two fixed-frame spherical-coordinate velocity variables. Results from the numerical implementation show the expected improvement [O(Δt) vs. O(Δt1/2)] in the strong convergence rate both for the speed |v| and angular components of the scattering. An important result is that this improved convergence is achieved for the angular component of the scattering if andmore » only if the “area-integral” terms in the Milstein scheme are included. The resulting Milstein scheme is of value as a step towards algorithms with both improved accuracy and efficiency. These include both algorithms with improved convergence in the averages (weak convergence) and multi-time-level schemes. The latter have been shown to give a greatly reduced cost for a given overall error level when compared with conventional Monte-Carlo schemes, and their performance is improved considerably when the Milstein algorithm is used for the underlying time advance versus the Euler-Maruyama algorithm. A new method for sampling the area integrals is given which is a simplification of an earlier direct method and which retains high accuracy. Lastly, this method, while being useful in its own right because of its relative simplicity, is also expected to considerably reduce the computational requirements for the direct conditional sampling of the area integrals that is needed for adaptive strong integration.« less

  16. Deep Upper Mantle Anisotropy from SKS Splitting Delay Times and Higher Mode Surface Waves

    NASA Astrophysics Data System (ADS)

    Yuan, K.; Beghein, C.; Davis, P. M.

    2014-12-01

    The splitting of SKS waves is widely used to study mantle anisotropy and to get insight on Earth's dynamic interior. However, while SKS splitting is an unambiguous signature of anisotropy, it cannot be used directly to infer the depth distribution of the anisotropy because the dealy times between the two polarization directions result from integrated measurements along quasi-vertical paths between the core-mantle boundary and the surface. SKS splitting data are generally interpreted in terms of olivine lattice preferred orientation in the uppermost 250 km of the mantle. There is, nevertheless, growing evidence from regional studies that the splitting may contain significant contributions from greater depths. In addition, SKS delay times are strongly under predicted by tomographic models of azimuthal anisotropy derived from fundamentqal mode surface waves. These models typically display anisotropy only in the 250 km of the mantle because fundamental mode surface wave data have little sensitivity to structure below that depth. For example, we calculated predictions of SKS splitting using the global azimuthal anisotropy model of Debayle et al. (2005), and found a global delay times distributon with a median of 0.4 s, compared to 1.1 s for the global station-averaged SKS splitting database compiled by Becker et al. (2012). This discrepancy may indicate that seismic anisotropy is present at greater depths. In this work, we analyzed a new global 3-D model of azimuthal anisotropy (Yuan and Beghein, 2013) that was obtained from the inversion of higher modes surface wave phase velocity data with unprecedented sensitivity to the top 1000 km of the mantle. While this model is comparable to previous models in the uppermost mantle, it also displays anisotropy amplitudes of about 1% below 250 km depth and a complex 3-D pattern of fast axes directions down to 800 km depth. The predicted SKS delay times calculated using this new model have a median of 0.75 s, which is in much

  17. Renewing Quality Assurance at a Time of Turbulence: An Attempt to Reenergise Quality in Australian Higher Education

    ERIC Educational Resources Information Center

    Shah, Mahsood; Nair, Chenicheri Sid

    2011-01-01

    The renewal of quality assurance in Australian higher education comes at a time when the higher education sectors in Australia and around the world are experiencing a number of key challenges. These include: ongoing decline in public funding of universities; the massification of higher education and demand for it during global recession;…

  18. What Is Going on in Higher Education? Is It Time for a Change?

    ERIC Educational Resources Information Center

    Hackman, Judith Dozier

    1992-01-01

    The president of the Association for the Study of Higher Education identifies four powerful forces causing disarray and turbulence in higher education: (1) increasing gender equality, (2) increasing globalism, (3) increasing multiculturalism, and (4) expanding technology. It is concluded that higher education needs to gather its forces, shift its…

  19. Part-Time Students and Part-Time Study in Higher Education in the UK: Strand 2--A Survey of the Issues Facing Institutions

    ERIC Educational Resources Information Center

    Boorman, Susan; Brown, Nigel; Payne, Philip; Ramsden, Brian

    2006-01-01

    This is the report on part-time study in UK higher education institutions (HEIs) for Universities UK and GuildHE (previously SCOP) from Nigel Brown Associates. It forms Strand 2 of the wider research into part-time higher education commissioned by Universities UK and GuildHE using quantitative data not available from published sources and…

  20. [Estimation of PM2.5 Concentration over the Yangtze Delta Using Remote Sensing: Analysis of Spatial and Temporal Variations].

    PubMed

    Xu, Jian-hui; Jiang, Hong

    2015-09-01

    Satellite remote sensing retrieved aerosol optical thickness is widely used to monitor surface PM2.5 concentration. In order to monitor PM2.5 by remote sensing in the Yangtze delta, estimate model of PM2.5 concentration was constructed based on MODIS AOT, PM2.5 concentration data of the 36 ground air quality observation sites and meteorological data in 2013. Afterwards, the model estimated PM2.5 was validated by PM2.5 concentration data from the 17 ground air quality observation sites, and the results showed that the model estimation was higher. The correlation coefficient value of R2 between model estimation of PM2.5 concentration and the value of the ground monitoring of spring, summer, autumn and winter were 0. 45, 0. 50, 0. 58 and 0. 52, respectively. The variation characteristics of temporal and spatial was analyzed based on the long time PM2.5 data together with model estimated, and an increase trend of PM2.5 concentration was observed from 2000 to 2013, with the maximum concentration of PM2.5 (66. 2 µg.m-3 ± 19. 3 µg.m-3) in February and minimum in December (22.6 µg.m-3 ± 5. 9 µg.m-3). In addition, it was found that the distribution of PM2.5 concentration was of obvious features, displaying high value in south and low in north. Mass concentration of PM2.5 was peaked in the zone of urban agglomeration which was grouped to a delta-shaped region by Shanghai, Hangzhou and Nanjing, while the low value areas were in the forest away from city. The result suggested that MODIS AOT and meteorological data can be used to monitor regional PM2.5 by the established multi-linear regression model.

  1. [Estimation of PM2.5 Concentration over the Yangtze Delta Using Remote Sensing: Analysis of Spatial and Temporal Variations].

    PubMed

    Xu, Jian-hui; Jiang, Hong

    2015-09-01

    Satellite remote sensing retrieved aerosol optical thickness is widely used to monitor surface PM2.5 concentration. In order to monitor PM2.5 by remote sensing in the Yangtze delta, estimate model of PM2.5 concentration was constructed based on MODIS AOT, PM2.5 concentration data of the 36 ground air quality observation sites and meteorological data in 2013. Afterwards, the model estimated PM2.5 was validated by PM2.5 concentration data from the 17 ground air quality observation sites, and the results showed that the model estimation was higher. The correlation coefficient value of R2 between model estimation of PM2.5 concentration and the value of the ground monitoring of spring, summer, autumn and winter were 0. 45, 0. 50, 0. 58 and 0. 52, respectively. The variation characteristics of temporal and spatial was analyzed based on the long time PM2.5 data together with model estimated, and an increase trend of PM2.5 concentration was observed from 2000 to 2013, with the maximum concentration of PM2.5 (66. 2 µg.m-3 ± 19. 3 µg.m-3) in February and minimum in December (22.6 µg.m-3 ± 5. 9 µg.m-3). In addition, it was found that the distribution of PM2.5 concentration was of obvious features, displaying high value in south and low in north. Mass concentration of PM2.5 was peaked in the zone of urban agglomeration which was grouped to a delta-shaped region by Shanghai, Hangzhou and Nanjing, while the low value areas were in the forest away from city. The result suggested that MODIS AOT and meteorological data can be used to monitor regional PM2.5 by the established multi-linear regression model. PMID:26717669

  2. PM2.5 Spatiotemporal Variations and the Relationship with Meteorological Factors during 2013-2014 in Beijing, China

    PubMed Central

    Wang, Chao; Xu, Qin; Wang, Wei; Luo, Yanxia; Tao, Lixin; Gao, Qi; Guo, Jin; Chen, Sipeng; Cao, Kai; Liu, Long; Gao, Ni; Liu, Xiangtong; Yang, Kun; Yan, Aoshuang; Guo, Xiuhua

    2015-01-01

    Objective Limited information is available regarding spatiotemporal variations of particles with median aerodynamic diameter < 2.5 μm (PM2.5) at high resolutions, and their relationships with meteorological factors in Beijing, China. This study aimed to detect spatiotemporal change patterns of PM2.5 from August 2013 to July 2014 in Beijing, and to assess the relationship between PM2.5 and meteorological factors. Methods Daily and hourly PM2.5 data from the Beijing Environmental Protection Bureau (BJEPB) were analyzed separately. Ordinary kriging (OK) interpolation, time-series graphs, Spearman correlation coefficient and coefficient of divergence (COD) were used to describe the spatiotemporal variations of PM2.5. The Kruskal-Wallis H test, Bonferroni correction, and Mann-Whitney U test were used to assess differences in PM2.5 levels associated with spatial and temporal factors including season, region, daytime and day of week. Relationships between daily PM2.5 and meteorological variables were analyzed using the generalized additive mixed model (GAMM). Results Annual mean and median of PM2.5 concentrations were 88.07 μg/m3 and 71.00 μg/m3, respectively, from August 2013 to July 2014. PM2.5 concentration was significantly higher in winter (P < 0.0083) and in the southern part of the city (P < 0.0167). Day to day variation of PM2.5 showed a long-term trend of fluctuations, with 2–6 peaks each month. PM2.5 concentration was significantly higher in the night than day (P < 0.0167). Meteorological factors were associated with daily PM2.5 concentration using the GAMM model (R2 = 0.59, AIC = 7373.84). Conclusion PM2.5 pollution in Beijing shows strong spatiotemporal variations. Meteorological factors influence the PM2.5 concentration with certain patterns. Generally, prior day wind speed, sunlight hours and precipitation are negatively correlated with PM2.5, whereas relative humidity and air pressure three days earlier are positively correlated with PM2.5. PMID

  3. 28 CFR 2.5 - Sentence aggregation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 28 Judicial Administration 1 2014-07-01 2014-07-01 false Sentence aggregation. 2.5 Section 2.5 Judicial Administration DEPARTMENT OF JUSTICE PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS... by the Commission pursuant to these rules, and the prisoner has a single parole eligibility date...

  4. 28 CFR 2.5 - Sentence aggregation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 28 Judicial Administration 1 2012-07-01 2012-07-01 false Sentence aggregation. 2.5 Section 2.5 Judicial Administration DEPARTMENT OF JUSTICE PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS... by the Commission pursuant to these rules, and the prisoner has a single parole eligibility date...

  5. 28 CFR 2.5 - Sentence aggregation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 28 Judicial Administration 1 2011-07-01 2011-07-01 false Sentence aggregation. 2.5 Section 2.5 Judicial Administration DEPARTMENT OF JUSTICE PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS... by the Commission pursuant to these rules, and the prisoner has a single parole eligibility date...

  6. 28 CFR 2.5 - Sentence aggregation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 28 Judicial Administration 1 2013-07-01 2013-07-01 false Sentence aggregation. 2.5 Section 2.5 Judicial Administration DEPARTMENT OF JUSTICE PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS... by the Commission pursuant to these rules, and the prisoner has a single parole eligibility date...

  7. [Spatial-temporal variations of extractable organic matter in atmospheric PM10 and PM2.5 in Beijing].

    PubMed

    Dong, Xue-Ling; Liu, Da-Meng; Yuan, Yang-Sen; Che, Rui-Jun

    2009-02-15

    PM10 and PM2.5 samples were collected in parallel in different function zones of Beijing during four seasons of 2005. The pollution level, distribution characteristics of the extractable organic matter (EOM) and relationship between EOM (PM10) and EOM (PM2.5) were illustrated. The results show that: the annual mean concentrations of organic compound in PM10 and PM2.5 are 41.39 microg/m3 and 34.84 microg/m3, being 1.44 times and 1.26 times higher than Ming Tombs site. The concentrations of EOM in winter are 67.04 microg/m3 (PM10) and 64.64 microg/m3 (PM2.5), which are 1.15 and 1.82 times, 2.06 and 2.26 times, 4.53 and 6.26 times higher than that in spring, autumn, summer, respectively. Ratios of EOM in PM2.5 to that in PM10 in different seasons exceed 0.60. In different function zones the concentrations of EOM present industrial and commercial zones > living, traffic and contrast zones. The influence of EOM (PM2.5) on EOM (PM10) in different districts are various. The order of annual concentrations of organic compositions is non-hydrocarbons > asphaltenes > aromatics > saturated hydrocarbon. The seasonal emissions of pollution sources play an important role in seasonality of compositions of EOM. PMID:19402477

  8. Troubled Times for American Higher Education: The 1990s and Beyond. SUNY Series, Frontiers in Education.

    ERIC Educational Resources Information Center

    Kerr, Clark; And Others

    This volume looks at the future of American higher education in 13 essays most of which were originally speeches to gatherings around the United States and the globe. The first series of essays in Part I looks at possible "contours" of the future and what choices should be made by higher education to advance the quality of future performance. One…

  9. Ecuador's Higher Education System in Times of Change

    ERIC Educational Resources Information Center

    Van Hoof, Hubert B.; Estrella, Mateo; Eljuri, Marie-Isabel; León, Leonardo Torres

    2013-01-01

    Ecuador's higher education system is undergoing dramatic changes. The National Constitution of 2008 and the Higher Education Law of 2010 have changed the way Ecuador's universities are funded, administered, and accredited. The importance of research was elevated and drastic changes were made to the academic qualifications and employment…

  10. The Changing Faces of Corruption in Georgian Higher Education: Access through Times and Tests

    ERIC Educational Resources Information Center

    Orkodashvili, Mariam

    2012-01-01

    This article presents a comparative-historical analysis of access to higher education in Georgia. It describes the workings of corrupt channels during the Soviet and early post-Soviet periods and the role of standardized tests in fighting corruption in higher education admission processes after introduction of the Unified National Entrance…

  11. Linking climate and air quality over Europe: effects of meteorology on PM2.5 concentrations

    NASA Astrophysics Data System (ADS)

    Megaritis, A. G.; Fountoukis, C.; Charalampidis, P. E.; Denier van der Gon, H. A. C.; Pilinis, C.; Pandis, S. N.

    2014-09-01

    The effects of various meteorological parameters such as temperature, wind speed, absolute humidity, precipitation and mixing height on PM2.5 concentrations over Europe were examined using a three-dimensional chemical transport model, PMCAMx-2008. Our simulations covered three periods, representative of different seasons (summer, winter, and fall). PM2.5 appears to be more sensitive to temperature changes compared to the other meteorological parameters in all seasons. PM2.5 generally decreases as temperature increases, although the predicted changes vary significantly in space and time, ranging from -700 ng m-3 K-1 (-8% K-1) to 300 ng m-3 K-1 (7% K-1). The predicted decreases of PM2.5 are mainly due to evaporation of ammonium nitrate, while the higher biogenic emissions and the accelerated gas-phase reaction rates increase the production of organic aerosol (OA) and sulfate, having the opposite effect on PM2.5. The predicted responses of PM2.5 to absolute humidity are also quite variable, ranging from -130 ng m-3 %-1 (-1.6% %-1) to 160 ng m-3 %-1 (1.6% %-1) dominated mainly by changes in inorganic PM2.5 species. An increase in absolute humidity favors the partitioning of nitrate to the aerosol phase and increases the average PM2.5 during summer and fall. Decreases in sulfate and sea salt levels govern the average PM2.5 response to humidity during winter. A decrease of wind speed (keeping the emissions constant) increases all PM2.5 species (on average 40 ng m-3 %-1) due to changes in dispersion and dry deposition. The wind speed effects on sea salt emissions are significant for PM2.5 concentrations over water and in coastal areas. Increases in precipitation have a negative effect on PM2.5 (decreases up to 110 ng m-3 %-1) in all periods due to increases in wet deposition of PM2.5 species and their gas precursors. Changes in mixing height have the smallest effects (up to 35 ng m-3 %-1) on PM2.5 . Regarding the relative importance of each of the meteorological

  12. Linking climate and air quality over Europe: effects of meteorology on PM2.5 concentrations

    NASA Astrophysics Data System (ADS)

    Megaritis, A. G.; Fountoukis, C.; Charalampidis, P. E.; Denier van der Gon, H. A. C.; Pilinis, C.; Pandis, S. N.

    2014-04-01

    The effects of various meteorological parameters such as temperature, wind speed, absolute humidity, precipitation and mixing height on PM2.5 concentrations over Europe were examined using a three-dimensional chemical transport model, PMCAMx-2008. Our simulations covered three periods, representative of different seasons (summer, winter, and fall). PM2.5 appears to be more sensitive to temperature changes compared to the other meteorological parameters in all seasons. PM2.5 generally decreases as temperature increases, although the predicted changes vary significantly in space and time, ranging from -700 ng m-3 K-1 (-8% K-1) to 300 ng m-3 K-1 (7% K-1). The predicted decreases of PM2.5 are mainly due to evaporation of ammonium nitrate, while the higher biogenic emissions and the accelerated gas-phase reaction rates increase the production of organic aerosol (OA) and sulfate, having the opposite effect on PM2.5. The predicted responses of PM2.5 to absolute humidity are also quite variable, ranging from -130 ng m-3%-1 (-1.6% %-1) to 160 ng m-3 %-1 (1.6% %-1) dominated mainly by changes in inorganic PM2.5 species. An increase in absolute humidity favors the partitioning of nitrate to the aerosol phase and increases the average PM2.5 during summer and fall. Decreases in sulfate and sea salt levels govern the average PM2.5 response to humidity during winter. A decrease of wind speed (keeping constant the emissions) increases all PM2.5 species (on average 40 ng m-3 %-1) due to changes in dispersion and dry deposition. The wind speed effects on sea salt emissions are significant for PM2.5 concentrations over water and in coastal areas. Increases in precipitation have a negative effect on PM2.5 (decreases up to 110 ng m-3 %-1) in all periods due to increases in wet deposition of PM2.5 species and their gas precursors. Changes in mixing height have the smallest effects (up to 35 ng m-3 %-1) on PM2.5. Regarding the relative importance of each of the meteorological parameters

  13. Rat lung response to ozone and fine particulate matter (PM2.5) exposures.

    PubMed

    Wang, Guanghe; Zhao, Jinzhuo; Jiang, Rongfang; Song, Weimin

    2015-03-01

    Exposure to different ambient pollutants maybe more toxic to lung than exposure to a single pollutant. In this study, we discussed the inflammation and oxidative stress responses of rat lung caused by ozone and PM2.5 versus that of rats exposed to saline, ozone, or single PM2.5 . Wistar rats inhaled 0.8 ppm ozone or air for 4 h and then placed in air for 3 h following intratracheal instillation with 0, 0.2 (low dose), 0.8 (medium dose), 3.2 (high dose) mg/rat PM2.5 dissolved in sterile saline (0.25 mL/rat), repeated twice per week for 3 weeks, the cumulative doses of PM2.5 in animals were 1.2, 4.8, and 19.2 mg. Rats were sacrificed 24 h after the last (sixth) exposure. The collected bronchoalveolar lavage fluid (BALF) was analyzed for inflammatory cells and cytokines. Lung tissues were processed for light microscopic and transmission electron microscopic (TEM) examinations. Results showed that total cell number in BALF of PM2.5 -exposed groups were higher than control (p < 0.05). PM2.5 instillation caused dose-trend increase in tumor necrosis factor alpha (TNF-α), interleukin-6, lactate dehydrogenase, and total protein of BALF. Exposure to ozone alone only caused TNF-α significant change in above-mentioned indicators of lung injury. On the other hand, ozone could enhance PM2.5-induced inflammatory changes and pathological characters in rat lungs. SOD and GSH-Px activities in lung were reduced in PM2.5-exposed rats with and without prior ozone exposure compared to control. To determine whether the PM2.5 and ozone affect endothelium system, iNOS, eNOS, and ICAM-1 mRNA levels in lung were analyzed by real-time PCR. These data demonstrated that inflammation and oxidative stress were involved in toxicology mechanisms of PM2.5 in rat lung and ozone potentiated these effects induced by PM2.5. These results have implications for understanding the pulmonary effects induced by ozone and PM2.5.

  14. Analysis of airborne particulate matter (PM2.5) over Hong Kong using remote sensing and GIS.

    PubMed

    Shi, Wenzhong; Wong, Man Sing; Wang, Jingzhi; Zhao, Yuanling

    2012-01-01

    Airborne fine particulates (PM(2.5); particulate matter with diameter less than 2.5 μm) are receiving increasing attention for their potential toxicities and roles in visibility and health. In this study, we interpreted the behavior of PM(2.5) and its correlation with meteorological parameters in Hong Kong, during 2007-2008. Significant diurnal variations of PM(2.5) concentrations were observed and showed a distinctive bimodal pattern with two marked peaks during the morning and evening rush hour times, due to dense traffic. The study observed higher PM(2.5) concentrations in winter when the northerly and northeasterly winds bring pollutants from the Chinese mainland, whereas southerly monsoon winds from the sea bring fresh air to the city in summer. In addition, higher concentrations of PM(2.5) were observed in rush hours on weekdays compared to weekends, suggesting the influence of anthropogenic activities on fine particulate levels, e.g., traffic-related local PM(2.5) emissions. To understand the spatial pattern of PM(2.5) concentrations in the context of the built-up environment of Hong Kong, we utilized MODerate Resolution Imaging Spectroradiometer (MODIS) Aerosol Optical Thickness (AOT) 500 m data and visibility data to derive aerosol extinction profile, then converted to aerosol and PM(2.5) vertical profiles. A Geographic Information Systems (GIS) prototype was developed to integrate atmospheric PM(2.5) vertical profiles with 3D GIS data. An example of the query function in GIS prototype is given. The resulting 3D database of PM(2.5) concentrations provides crucial information to air quality regulators and decision makers to comply with air quality standards and in devising control strategies.

  15. Part-Time Students and Part-Time Study in Higher Education in the UK: Strand 1--A Quantitative Data Analysis of 2003/04 HESA Data

    ERIC Educational Resources Information Center

    Ramsden, Brian

    2006-01-01

    This is a report of the Strand 1 element of the Universities UK project to examine part-time students and part-time study within the United Kingdom. The aim of Strand 1 of this project is to set out, as far as possible, factual information about students studying part-time and following programmes of study leading to higher education…

  16. PM2.5 Indoor Air Quality at Two Sites in London Ontario - A Case Study

    NASA Astrophysics Data System (ADS)

    Mates, A. V.; Xu, X.; Gilliland, J.; Maltby, M. J.

    2010-12-01

    Studies have shown an association between ambient fine particulate matter (PM2.5) and health impacts, particularly for the elderly and children. As part of a larger study, PM2.5 concentrations were measured using the DustTrak (Model 8520, TSI, St. Paul, MN, USA) at two schools within the city of London, Ontario (Canada). Site A was in a suburban environment while site B was in an urban setting. Monitoring took place for 3 weeks during winter (Feb. 16 - Mar. 8) and 3 weeks during spring (May 05 - 25) of 2010. The winter campaign monitored indoor PM2.5 only, while the spring campaign added outdoor monitors (PM2.5 and CO2) after the first week. Ten min. concentrations were used for analysis. Indoor measurements were split into weekday and weekend. For the same time interval, the outdoor concentrations showed mean values of 18 and 21 μg/m3 for sites A & B, respectively, both under the Canada Wide Standard of 30 μg/m3. Measurements at the two sites showed good associations (R^2 = 0.44), during the spring campaign. This indicates that the outdoor PM2.5 had similar sources. For indoor concentrations, Site B showed a significantly different mean concentration 5 times higher compared to site A during the winter ( 8.1 vs. 1.5 μg/m3 ) and 3 times higher (11.9 vs. 3.7 μg/m3) during the spring campaign. Since the outdoor concentrations were similar the large difference in indoor concentrations could be attributed to the following factors: site B being an older building, and the different physical characteristics between the two sites. The spring measurements showed an increase of 50% from weekday to weekend for site A and 22% for site B. The higher level of PM2.5 during weekends is possibly due to the infiltration of outdoor air while the ventilation/filtration system is shut off. During the winter campaign, Site A showed a 14% higher concentration during weekdays compared to weekends while site B weekend concentrations were 17% higher compared to weekday, which will be

  17. Use of Part-Time Faculty in Higher Education: Numbers and Impact. Briefing Papers.

    ERIC Educational Resources Information Center

    Miller, Ross

    Colleges and universities of all kinds rely on part-time faculty to teach students from the freshman year through graduate studies, although they are more likely to teach lower division students. Overall, 43% of postsecondary instructional faculty work part-time, while full-time tenure track positions are held by about 18% of faculty members.…

  18. The Impact of Part-Time Faculty on Student Retention: A Case Study in Higher Education

    ERIC Educational Resources Information Center

    Smith, Curtis V.

    2010-01-01

    There has been considerable debate in community colleges over the last forty years regarding the impact of increased use of part-time faculty (PTF) on student learning. It has been argued that part-time faculty fail to provide the same level of teaching quality as full-time faculty (FTF). The purpose of this study was to determine the impact of…

  19. Classical and quantum-mechanical axioms with the higher time derivative formalism

    NASA Astrophysics Data System (ADS)

    Kamalov, Timur

    2013-06-01

    A Newtonian mechanics model is essentially the model of a point body in an inertial reference frame. How to describe extended bodies in non-inertial (vibration) reference frames with the random initial conditions? One of the most generalized ways of descriptions (known as the higher derivatives formalism) consists in taking into account the infinite number of the higher temporal derivatives of the coordinates in the Lagrange function. Such formalism describing physical objects in the infinite dimensions space does not contradict to the quantum mechanics and infinite dimensions Hilbert space.

  20. Assessment of Remotely Sensed AOD-based PM2.5 Data for the CDC Tracking Network

    NASA Astrophysics Data System (ADS)

    Hu, X.; Vaidyanathan, A.; Qualters, J.; Liu, Y.

    2012-12-01

    Fine particulate matter (PM2.5) is small enough to invade air pathways in the body, and numerous health studies have examined the adverse health effects associated with exposure to PM2.5. PM2.5 ambient air concentration measurements are available from EPA's Air Quality System (AQS); however, monitors are not located in every county and do not sample for PM2.5 on a daily schedule. To estimate PM2.5 at highly resolved geographic and time scales, CDC collaborated with EPA on the development of a hierarchical Bayesian (HB) model to predict daily PM2.5 concentrations for use in the Environmental Public Health Tracking Network (Tracking Network). Meanwhile, satellite-retrieved Aerosol Optical Depth (AOD) can be converted to ambient PM2.5 estimates. We present the evaluation of satellite PM2.5 against AQS-based and HB-based PM2.5 predictions for the Southeastern U.S., and assess the feasibility of generating county-level measures from satellite PM2.5 for use in the Tracking Network. The study area contains 3702 12 km x 12 km grid cells, 102 AQS monitors and accounts for approximately 24 million people. The completeness of AOD data in the study domain ranged between 40 - 63 %. AOD-based PM2.5 estimates correlate well (r >0.8) with AQS-based measurements at most monitor locations. Median absolute difference between HB- and satellite PM2.5 estimates was 0.1 microgram/m3 with an interquartile range of 2.3 microgram/m3. In conclusion, remotely sensed AOD-based estimates are available on a near real-time basis and could help generate daily PM2.5 estimates at the county-level. The processing of satellite data is computationally less intensive than executing the HB model. While there are several benefits to using AOD-based estimates, there are a few limitations: data availability is limited by cloud cover and other atmospheric factors; data completeness could vary with season. These limitations notwithstanding, AOD-based PM2.5 estimates could be used to generate measures that are

  1. Estimation of anthropogenic PM2.5 emissions over Asian mega cities by integrating remote sensing and modeling

    NASA Astrophysics Data System (ADS)

    Kishi, H.; Takeuchi, W.; Sawada, H.

    2011-12-01

    Particulate matter whose aerodynamic diameter is less than 2.5 um (PM2.5) is one of the major pollutants that affect human health with causing asthma and even cancer. Emission standards for PM2.5 are establishing only in some countries and regions mainly because it is difficult to understand the atmospheric behaviors of PM2.5 spatially and temporally. This study aims to estimate atmospheric conditions focusing on PM2.5 with integrating remote sensing measurement and model estimation with bottom-up approach over global mega cities. Firstly, emitted PM2.5 is estimated by bottom-up approach modeling according to emissions sources such as exhaust emissions and biomass burning from 2000 to 2010 over global scale. They are estimated by developed model with paper review and land cover properties obtained by satellite measurements. Exhaust emission PM2.5 is estimated by total numbers of diesel vehicles in use, the number of population and emission standards regulated by governmental raw. Biomass burning PM2.5 is estimated by the number of hot spots detected by Moderate resolution imaging spectroradiometer (MODIS), fuel loading equivalent to the amount of field biomass, combustion factors estimated by vegetation moisture conditions and PM2.5 emission factors. Secondly, estimation errors of estimated PM2.5 emissions are evaluated by comparing reported PM2.5 emission inventories spatially and temporally. Black carbon and Organic carbon emissions estimated by Streets and REAS emission inventory are employed to compare model estimated PM2.5. Thirdly, integrated exhaust emissions and biomass burning PM2.5 is compared with MODIS Aerosol Optical Depth (AOD) measurement which is equivalent to total amount of PM2.5. Spatio-temporal patterns are analyzed between model estimated and satellite measured PM2.5. In case of Asian regions Easter than India, it is found that the highest PM2.5 concentration is observed in Hanoi 3.2 times higher than that in Tokyo over Asian mega cities

  2. The Challenge and Promise of Catholic Higher Education for Our Time

    ERIC Educational Resources Information Center

    Jenkins, John I.

    2015-01-01

    Catholic colleges and universities face significant challenges in the present context of American higher education. Yet, there are opportunities to be found in the midst of this crisis when one carefully examines the intersections between the Catholic mission and objectives of an institution and current culture and academia. A return to the…

  3. Catching the Window of Opportunity: Being on Time for Higher Education.

    ERIC Educational Resources Information Center

    Kempner, Ken; Kinnick, Mary

    1990-01-01

    A longitudinal study of 2100 high school students indicates a "window of opportunity" opens for individuals entering higher education immediately after high school. Students delaying college entry are less likely to attain a bachelor's degree. The finding is critical for students without characteristics to mediate the disadvantage of stopping out.…

  4. Challenges to Christian Higher Education at a Time of Increasing Emphasis on Research

    ERIC Educational Resources Information Center

    Hemmings, Brian; Hill, Doug

    2014-01-01

    In Australia, both Christian and non-Christian higher education institutions (HEIs) have experienced a rapidly changing external environment that is becoming more performance-driven, particularly in relation to faculty research. Academics working in Australian Christian HEIs often feel pressure to keep pace with their counterparts in non-Christian…

  5. Rural Education: A Field of Study Whose Time Has Come in Higher Education.

    ERIC Educational Resources Information Center

    Warner, Richard W., Jr.; Kale, Karen E.

    Although professional educators and public school decision makers have attempted to respond to increased educational demands and a broader spectrum of students, the education of rural youth is a neglected area both in higher education and in educational legislation. The record indicates that policy decisions and the resulting legislation have…

  6. Retention and Attrition of Students in Higher Education: Challenges in Modern Times to What Works

    ERIC Educational Resources Information Center

    Maher, Marguerite; Macallister, Helen

    2013-01-01

    Retention and attrition rates in higher education have long been a focus of research. This paper presents findings of a single case study, undertaken in a School of Education, which identify important strategies that have led to attrition of five to eight per cent, compared with 18 per cent cross the education sector in Australia (Department of…

  7. The Effective Academic: A Handbook for Enhanced Academic Practice. The Times Higher Education Supplement.

    ERIC Educational Resources Information Center

    Ketteridge, Steve, Ed.; Marshall, Stephanie, Ed.; Fry, Heather, Ed.

    This handbook provides guidance about controlling and directing an academic career by suggesting systematic approaches to key areas of responsibility and activity. It explores management and leadership in higher education, developing and promoting research and teaching, and coping with the changing university environment. The chapters of part 1,…

  8. Examining a Higher Education Funding Formula in a Time of Shifting Currents: Kentucky's Benchmark Approach

    ERIC Educational Resources Information Center

    Wall, Andrew; Frost, Robert; Smith, Ryan; Keeling, Richard

    2008-01-01

    Although datasets such as the Integrated Postsecondary Data System are available as inputs to higher education funding formulas, these datasets can be unreliable, incomplete, or unresponsive to criteria identified by state education officials. State formulas do not always match the state's economic and human capital goals. This article analyzes…

  9. Integrating Health and Sustainability: The Higher Education Sector as a Timely Catalyst

    ERIC Educational Resources Information Center

    Orme, J.; Dooris, M.

    2010-01-01

    Higher education is an influential sector with enormous potential to impact positively on health and sustainability. The purpose of this paper was to explore its emergent role as a key setting for promoting health and sustainability and for addressing their challenges in an integrated and coherent way. Acknowledging both the relative narrowness of…

  10. Breadth vs. Depth: The Timing of Specialization in Higher Education. NBER Working Paper No. 15943

    ERIC Educational Resources Information Center

    Malamud, Ofer

    2010-01-01

    This paper examines the tradeoff between early and late specialization in the context of higher education. While some educational systems require students to specialize early by choosing a major field of study prior to entering university, others allow students to postpone this choice. I develop a model in which individuals, by taking courses in…

  11. First integrals for time-dependent higher-order Riccati equations by nonholonomic transformation

    NASA Astrophysics Data System (ADS)

    Guha, Partha; Ghose Choudhury, A.; Khanra, Barun

    2011-08-01

    We exploit the notion of nonholonomic transformations to deduce a time-dependent first integral for a (generalized) second-order nonautonomous Riccati differential equation. It is further shown that the method can also be used to compute the first integrals of a particular class of third-order time-dependent ordinary differential equations and is therefore quite robust.

  12. The Impact of Term-Time Employment on Higher Education Students' Academic Attainment and Achievement

    ERIC Educational Resources Information Center

    Callender, Claire

    2008-01-01

    Term-time employment among Britain's undergraduates is a growing phenomenon but it has received scant attention from government and policy makers. Although there are numerous studies on the subject, few have explored the impact of term-time employment on students' actual attainment and those that have are limited. This article attempts to fill…

  13. Do Diligent Students Perform Better? Complex Relations between Student and Course Characteristics, Study Time, and Academic Performance in Higher Education

    ERIC Educational Resources Information Center

    Masui, Chris; Broeckmans, Jan; Doumen, Sarah; Groenen, Anne; Molenberghs, Geert

    2014-01-01

    Research has reported equivocal results regarding the relationship between study time investment and academic performance in higher education. In the setting of the active, assignment-based teaching approach at Hasselt University (Belgium), the present study aimed (a) to further clarify the role of study time in academic performance, while taking…

  14. Integrating health and sustainability: the higher education sector as a timely catalyst.

    PubMed

    Orme, J; Dooris, M

    2010-06-01

    Higher education is an influential sector with enormous potential to impact positively on health and sustainability. The purpose of this paper was to explore its emergent role as a key setting for promoting health and sustainability and for addressing their challenges in an integrated and coherent way. Acknowledging both the relative narrowness of the environmental focus that has to date characterized and driven universities' work in relation to sustainability and the demonstrable value of adopting a whole-system approach, this paper will explore the concept of 'Healthy Universities' as a means of furthering debate and facilitating synergy between public health, sustainable development and climate change. Higher education represents one large-scale sector with a unique combination of roles that can be harnessed to focus and mobilize its education, knowledge exchange, research, corporate responsibility and future shaping agendas to achieve significant impacts in this area. It is the growing commitment to embedding health and well-being within the mainstream business of higher education coupled with the expectation that universities will act sustainably in all that they do that provides the perfect springboard to influence a process of 'co-ordinated action' to address climate change and impact positively on the integrated health and sustainability agenda. PMID:20382673

  15. Integrating health and sustainability: the higher education sector as a timely catalyst.

    PubMed

    Orme, J; Dooris, M

    2010-06-01

    Higher education is an influential sector with enormous potential to impact positively on health and sustainability. The purpose of this paper was to explore its emergent role as a key setting for promoting health and sustainability and for addressing their challenges in an integrated and coherent way. Acknowledging both the relative narrowness of the environmental focus that has to date characterized and driven universities' work in relation to sustainability and the demonstrable value of adopting a whole-system approach, this paper will explore the concept of 'Healthy Universities' as a means of furthering debate and facilitating synergy between public health, sustainable development and climate change. Higher education represents one large-scale sector with a unique combination of roles that can be harnessed to focus and mobilize its education, knowledge exchange, research, corporate responsibility and future shaping agendas to achieve significant impacts in this area. It is the growing commitment to embedding health and well-being within the mainstream business of higher education coupled with the expectation that universities will act sustainably in all that they do that provides the perfect springboard to influence a process of 'co-ordinated action' to address climate change and impact positively on the integrated health and sustainability agenda.

  16. On-road PM2.5 pollution exposure in multiple transport microenvironments in Delhi

    NASA Astrophysics Data System (ADS)

    Goel, Rahul; Gani, Shahzad; Guttikunda, Sarath K.; Wilson, Daniel; Tiwari, Geetam

    2015-12-01

    PM2.5 pollution in Delhi averaged 150 μg/m3 from 2012 through 2014, which is 15 times higher than the World Health Organization's annual-average guideline. For this setting, we present on-road exposure of PM2.5 concentrations for 11 transport microenvironments along a fixed 8.3-km arterial route, during morning rush hour. The data collection was carried out using a portable TSI DustTrak DRX 8433 aerosol monitor, between January and May (2014). The monthly-average measured ambient concentrations varied from 130 μg/m3 to 250 μg/m3. The on-road PM2.5 concentrations exceeded the ambient measurements by an average of 40% for walking, 10% for cycle, 30% for motorised two wheeler (2W), 30% for open-windowed (OW) car, 30% for auto rickshaw, 20% for air-conditioned as well as for OW bus, 20% for bus stop, and 30% for underground metro station. On the other hand, concentrations were lower by 50% inside air-conditioned (AC) car and 20% inside the metro rail carriage. We find that the percent exceedance for open modes (cycle, auto rickshaw, 2W, OW car, and OW bus) reduces non-linearly with increasing ambient concentration. The reduction is steeper at concentrations lower than 150 μg/m3 than at higher concentrations. After accounting for air inhalation rate and speed of travel, PM2.5 mass uptake per kilometer during cycling is 9 times of AC car, the mode with the lowest exposure. At current level of concentrations, an hour of cycling in Delhi during morning rush-hour period results in PM2.5 dose which is 40% higher than an entire-day dose in cities like Tokyo, London, and New York, where ambient concentrations range from 10 to 20 μg/m3.

  17. Characterization of the solvent extractable organic compounds in PM2.5 aerosols in Hong Kong

    NASA Astrophysics Data System (ADS)

    Zheng, Mei; Fang, Ming; Wang, Fu; To, K. L.

    The results from a year-long monthly study of the solvent extractable organic compounds (SEOC) in PM2.5 of the ambient aerosols in Hong Kong are reported. A total of 18 samples were analyzed. The extracted organic compounds were separated into four major fractions ( n-alkanes, fatty acids, alkanols and PAHs (polycyclic aromatic hydrocarbons)) and identified with GC-MS (gas chromatography-mass spectrometry). The percentage of each fraction in total yield is as follows: fatty acids at 46-80%, alkanes at 10-34%, alkanols at 4-21%, and PAHs at 1-6%. Compared to the TSP (total suspended particulates) samples from our previous studies, the PAH fraction was higher in PM2.5 than TSP (0.5-2.5%). The bias of PAHs in PM2.5 suggests potential implications in health impact because PM2.5 is respirable. The total yield (defined as the sum of the four fractions) in PM2.5 was in the range of 56.4-233.6 ng m -3. The sources of SEOC in PM2.5 could be attributed to vehicular, biogenic and microbial origins. On the average, 79% of the alkanes in PM2.5 came from vehicular emissions. U: R (ratio of unresolved to resolved components), an index to assess the magnitude of petroleum residues in aerosols, exhibited higher values in PM2.5 (average 3.2, range 1.0-5.9) than TSP (average 2.4, range 1.1-3.3). CPI (carbon preference index) of alkanes showed an inverse relationship with U: R, and a positive correlation with the percentage of alkanes from higher plant wax. Although U: R and CPI have been widely used as indices in source apportionment, their effectiveness was demonstrated for the first time from the statistical point of view in this paper. It was discovered that the CPI=1 (a characteristic of petroleum hydrocarbons) envelope and Cmax shifted towards lower carbon numbers in winter, suggesting there was more contribution from vehicular emission. PAHs had the following range 0.7-12.2 ng m -3. The positive correlation with benzo(ghi)perylene suggested that they were of vehicular origin

  18. Black carbon and particulate matter (PM2.5) concentrations in New York City's subway stations.

    PubMed

    Vilcassim, M J Ruzmyn; Thurston, George D; Peltier, Richard E; Gordon, Terry

    2014-12-16

    The New York City (NYC) subway is the main mode of transport for over 5 million passengers on an average weekday. Therefore, airborne pollutants in the subway stations could have a significant impact on commuters and subway workers. This study looked at black carbon (BC) and particulate matter (PM2.5) concentrations in selected subway stations in Manhattan. BC and PM2.5 levels were measured in real time using a Micro-Aethalometer and a PDR-1500 DataRAM, respectively. Simultaneous samples were also collected on quartz filters for organic and elemental carbon (OC/EC) analysis and on Teflon filters for gravimetric and trace element analysis. In the underground subway stations, mean real time BC concentrations ranged from 5 to 23 μg/m(3), with 1 min average peaks >100 μg/m(3), while real time PM2.5 levels ranged from 35 to 200 μg/m(3). Mean EC levels ranged from 9 to 12.5 μg/m(3). At street level on the same days, the mean BC and PM2.5 concentrations were below 3 and 10 μg/m(3), respectively. This study shows that both BC soot and PM levels in NYC's subways are considerably higher than ambient urban street levels and that further monitoring and investigation of BC and PM subway exposures are warranted. PMID:25409007

  19. Black carbon and particulate matter (PM2.5) concentrations in New York City's subway stations.

    PubMed

    Vilcassim, M J Ruzmyn; Thurston, George D; Peltier, Richard E; Gordon, Terry

    2014-12-16

    The New York City (NYC) subway is the main mode of transport for over 5 million passengers on an average weekday. Therefore, airborne pollutants in the subway stations could have a significant impact on commuters and subway workers. This study looked at black carbon (BC) and particulate matter (PM2.5) concentrations in selected subway stations in Manhattan. BC and PM2.5 levels were measured in real time using a Micro-Aethalometer and a PDR-1500 DataRAM, respectively. Simultaneous samples were also collected on quartz filters for organic and elemental carbon (OC/EC) analysis and on Teflon filters for gravimetric and trace element analysis. In the underground subway stations, mean real time BC concentrations ranged from 5 to 23 μg/m(3), with 1 min average peaks >100 μg/m(3), while real time PM2.5 levels ranged from 35 to 200 μg/m(3). Mean EC levels ranged from 9 to 12.5 μg/m(3). At street level on the same days, the mean BC and PM2.5 concentrations were below 3 and 10 μg/m(3), respectively. This study shows that both BC soot and PM levels in NYC's subways are considerably higher than ambient urban street levels and that further monitoring and investigation of BC and PM subway exposures are warranted.

  20. Spanish Zimbardo Time Perspective Inventory Construction and Validity among Higher Education Students

    ERIC Educational Resources Information Center

    Usart, Mireia; Romero, Margarida

    2014-01-01

    Introduction: The study of "Time Orientation" (TO) has been focused on how to measure this construct and its effects on human behavior. Defined as a fundamental psychological variable, TO is multidimensional, sensible to cultural differences and age. Although its relation to learning, it deserves further study in the different Higher…

  1. Higher Dimensional Clayton–Oakes Models for Multivariate Failure Time Data

    PubMed Central

    Prentice, R. L.

    2016-01-01

    Summary The Clayton–Oakes bivariate failure time model is extended to dimensions m > 2 in a manner that allows unspecified marginal survivor functions for all dimensions less than m. Special cases that allow unspecified marginal survivor functions of dimension q with q < m, while making some provisions for dependencies of dimension greater than q, are also described. PMID:27738350

  2. Widening Participation, Social Justice and Injustice: Part-Time Students in Higher Education in England

    ERIC Educational Resources Information Center

    Callender, Claire

    2011-01-01

    This article critically assesses the nature and scope of current financial support for part-time undergraduates in England, highlighting its importance for widening participation. It considers the limitations of these financial arrangements, why they are in need of reform, and some of the consequences of their inadequacies. The paper argues that…

  3. Preparation and Support of Part-Time Teachers in Higher Education.

    ERIC Educational Resources Information Center

    Nicol, David J.

    2000-01-01

    Examines research on preparation and support of part-time faculty, analyzing four areas of support: institutional policies and practices, formal preparation programs, monitoring and evaluation systems, and formal and informal support measures in academic departments. Key processes and problems in each area are discussed, examining issues that must…

  4. Transformation or Decline? Using Tough Times to Create Higher-Performing Schools

    ERIC Educational Resources Information Center

    Miles, Karen Hawley

    2011-01-01

    Instead of doing less with less during these fiscally challenging times, school districts can seize the moment to usher in school transformation that will leave the schools, families, and communities better off. They could follow the lead of districts such as Baltimore City, Syracuse, and Charlotte-Mecklenburg to think outside traditional cost…

  5. Lyapunov-type inequality for a higher order dynamic equation on time scales.

    PubMed

    Sun, Taixiang; Xi, Hongjian

    2016-01-01

    The purpose of this work is to establish a Lyapunov-type inequality for the following dynamic equation [Formula: see text]on some time scale T under the anti-periodic boundary conditions [Formula: see text], where [Formula: see text] for [Formula: see text] and [Formula: see text], [Formula: see text] with [Formula: see text] and [Formula: see text], p is the quotient of two odd positive integers and [Formula: see text] with [Formula: see text]. PMID:27652044

  6. Comparisons of urban and rural PM10-2.5 and PM2.5 mass concentrations and semi-volatile fractions in northeastern Colorado

    NASA Astrophysics Data System (ADS)

    Clements, Nicholas; Hannigan, Michael P.; Miller, Shelly L.; Peel, Jennifer L.; Milford, Jana B.

    2016-06-01

    Coarse (PM10-2.5) and fine (PM2.5) particulate matter in the atmosphere adversely affect human health and influence climate. While PM2.5 is relatively well studied, less is known about the sources and fate of PM10-2.5. The Colorado Coarse Rural-Urban Sources and Health (CCRUSH) study measured PM10-2.5 and PM2.5 mass concentrations, as well as the fraction of semi-volatile material (SVM) in each size regime (SVM2.5, SVM10-2.5), from 2009 to early 2012 in Denver and comparatively rural Greeley, Colorado. Agricultural operations east of Greeley appear to have contributed to the peak PM10-2.5 concentrations there, but concentrations were generally lower in Greeley than in Denver. Traffic-influenced sites in Denver had PM10-2.5 concentrations that averaged from 14.6 to 19.7 µg m-3 and mean PM10-2.5 / PM10 ratios of 0.56 to 0.70, higher than at residential sites in Denver or Greeley. PM10-2.5 concentrations were more temporally variable than PM2.5 concentrations. Concentrations of the two pollutants were not correlated. Spatial correlations of daily averaged PM10-2.5 concentrations ranged from 0.59 to 0.62 for pairs of sites in Denver and from 0.47 to 0.70 between Denver and Greeley. Compared to PM10-2.5, concentrations of PM2.5 were more correlated across sites within Denver and less correlated between Denver and Greeley. PM10-2.5 concentrations were highest during the summer and early fall, while PM2.5 and SVM2.5 concentrations peaked in winter during periodic multi-day inversions. SVM10-2.5 concentrations were low at all sites. Diurnal peaks in PM10-2.5 and PM2.5 concentrations corresponded to morning and afternoon peaks of traffic activity, and were enhanced by boundary layer dynamics. SVM2.5 concentrations peaked around noon on both weekdays and weekends. PM10-2.5 concentrations at sites located near highways generally increased with wind speeds above about 3 m s-1. Little wind speed dependence was observed for the residential sites in Denver and Greeley. The mass

  7. 43 CFR 3101.2-5 - Computation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) OIL AND GAS LEASING Issuance of Leases § 3101.2-5... more than 10 percent of the stock of a corporation which holds Federal oil and gas leases shall be the... holding of acreage in common by the same persons in excess of the maximum acreage specified in the...

  8. 36 CFR 2.5 - Research specimens.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Section 2.5 Parks, Forests, and Public Property NATIONAL PARK SERVICE, DEPARTMENT OF THE INTERIOR RESOURCE... outside of the park area and the primary purpose of the collection is to enhance the protection or... has the potential for improving the management and protection of park resources. (e) In park...

  9. 12 CFR 2.5 - Bank compensation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY SALES OF CREDIT LIFE INSURANCE § 2.5 Bank... turn over to the bank as compensation all income received from the sale of the credit life insurance to the bank's loan customers. (b) Income derived from credit life insurance sales to loan customers...

  10. Palladium-catalyzed 2,5-diheteroarylation of 2,5-dibromothiophene derivatives

    PubMed Central

    Belkessam, Fatma; Mohand, Aidene; Soulé, Jean-François

    2014-01-01

    Summary Conditions allowing the one pot 2,5-diheteroarylation of 2,5-dibromothiophene derivatives in the presence of palladium catalysts are reported. Using KOAc as the base, DMA as the solvent and only 0.5–2 mol % palladium catalysts, the target 2,5-diheteroarylated thiophenes were obtained in moderate to good yields and with a wide variety of heteroarenes such as thiazoles, thiophenes, furans, pyrroles, pyrazoles or isoxazoles. Moreover, sequential heteroarylation reactions allow the access to 2,5-diheteroarylated thiophenes bearing two different heteroaryl units. PMID:25550758

  11. Cooperative Weblog Learning in Higher Education: Its Facilitating Effects on Social Interaction, Time Lag, and Cognitive Load

    ERIC Educational Resources Information Center

    Huang, Tien-Chi; Huang, Yueh-Min; Yu, Fu-Yun

    2011-01-01

    This paper examines the effects of using weblog technologies to support cooperative learning in higher education. The study focused on the effects of features embedded in weblogs on social interactions, time lags, and cognitive loads. A quasi-experimental control-group research design was adopted. The participants were 115 undergraduates who were…

  12. Impact of the Headscarf Ban Policy on the Identity Development of Part-Time Unveilers in Turkish Higher Education

    ERIC Educational Resources Information Center

    Seggie, Fatma Nevra; Austin, Ann E.

    2010-01-01

    This qualitative study examines the impact of the Turkish higher education headscarf ban policy on the plural self-identities (i.e., as Turkish citizens, as Muslims, and as females) of part-time unveilers, female students who cover their hair in their private life but who remove the headscarf (or conceal it to appear unveiled) while at a Turkish…

  13. Utilizing Social Networks in Times of Crisis: Understanding, Exploring and Analyzing Critical Incident Management at Institutions of Higher Education

    ERIC Educational Resources Information Center

    Asselin, Martha Jo

    2012-01-01

    With the rising number of major crises on college campuses today (Security on Campus Inc., 2009), institutions of higher education can benefit from understanding of how social networks may be used in times of emergency. What is currently known about the usage of social networks is not integral to the current practices of crisis management that are…

  14. Modern U-Pb chronometry of meteorites: advancing to higher time resolution reveals new problems

    USGS Publications Warehouse

    Amelin, Y.; Connelly, J.; Zartman, R.E.; Chen, J.-H.; Gopel, C.; Neymark, L.A.

    2009-01-01

    In this paper, we evaluate the factors that influence the accuracy of lead (Pb)-isotopic ages of meteorites, and may possibly be responsible for inconsistencies between Pb-isotopic and extinct nuclide timescales of the early Solar System: instrumental mass fractionation and other possible analytical sources of error, presence of more than one component of non-radiogenic Pb, migration of ancient radiogenic Pb by diffusion and other mechanisms, possible heterogeneity of the isotopic composition of uranium (U), uncertainties in the decay constants of uranium isotopes, possible presence of "freshly synthesized" actinides with short half-life (e.g. 234U) in the early Solar System, possible initial disequilibrium in the uranium decay chains, and potential fractionation of radiogenic Pb isotopes and U isotopes caused by alpha-recoil and subsequent laboratory treatment. We review the use of 232Th/238U values to assist in making accurate interpretations of the U-Pb ages of meteorite components. We discuss recently published U-Pb dates of calcium-aluminum-rich inclusions (CAIs), and their apparent disagreement with the extinct nuclide dates, in the context of capability and common pitfalls in modern meteorite chronology. Finally, we discuss the requirements of meteorites that are intended to be used as the reference points in building a consistent time scale of the early Solar System, based on the combined use of the U-Pb system and extinct nuclide chronometers.

  15. Higher dimensional analysis shows reduced dynamism of time-varying network connectivity in schizophrenia patients.

    PubMed

    Miller, Robyn L; Yaesoubi, Maziar; Calhoun, Vince D

    2014-01-01

    Assessments of functional connectivity between brain networks is a fixture of resting state fMRI research. Until very recently most of this work proceeded from an assumption of stationarity in resting state network connectivity. In the last few years however, interest in moving beyond this simplifying assumption has grown considerably. Applying group temporal independent component analysis (tICA) to a set of time-varying functional network connectivity (FNC) matrices derived from a large multi-site fMRI dataset (N=314; 163 healthy, 151 schizophrenia patients), we obtain a set of five basic correlation patterns (component spatial maps (SMs)) from which observed FNCs can be expressed as mutually independent linear combinations, i.e., the coefficient on each SM in the linear combination is maximally independent of the others. We study dynamic properties of network connectivity as they are reflected in this five-dimensional space, and report stark differences in connectivity dynamics between schizophrenia patients and healthy controls. We also find that the most important global differences in FNC dynamism between patient and control groups are replicated when the same dynamical analysis is performed on sets of correlation patterns obtained from either PCA or spatial ICA, giving us additional confidence in the results.

  16. Weekly cycle of magnetic characteristics of PM2.5 and PM2.5-10 in Beijing, China

    NASA Astrophysics Data System (ADS)

    SHI, M.; Wu, H.; Zhang, S.; Li, H.; Yang, T.

    2013-12-01

    In urban areas,fine particle matter with aerodynamic diameter between 2.5 um and 10 um (PM2.5-10), and 2.5 um (PM2.5), as an important source of urban particulate matter (PM) pollutants, have significant negative effects on health, atmospheric visibility and climate. PM has increasingly become a significant index of indicating the atmospheric pollution of city. In recent years, Beijing, China has been listed as one of the most serious air pollution city in the world. In order to investigate the sources of air pollutants, a total of 283 pairs of PM2.5 and PM2.5-10 samples were collected daily from July, 2010 to June, 2011 in Beijing. Mineral magnetic properties and Scanning electron microscope (SEM) observations and energy dispersive X-ray spectroscopy (EDS) analyses of PM2.5 and PM2.5-10 were measured to verify the magnetic materials. Magnetic measures for PM indicated that the major magnetic phase was coarse-grained magnetite-like material. The χlf, χarm, SIRM and χarm/SIRM series of the PM2.5 and PM2.5-10 show seasonal dependences: high values in winter and low values in summer. In additional the parameters analyzed by Time-series methods show a strong cycle about 7 days above 95% confidence level. Weekly cycle of magnetic characteristics of PM2.5 and PM2.5-10 show different pattern: the concentration of magnetic particles in PM2.5-10 show high values in mid-week, and particle sizes is steady, while the concentration of magnetic particles in PM2.5 show reverse a weekly cycle pattern, and particle sizes is smaller in the mid-week.Microscopy analyses reveal basically three morphologies of magnetic grains: aggregate, spherules and angular particles. The ultrafine carbonaceous particles which tend to form complex clusters and chain-like structures, most likely come from coal burning and motor vehicle exhaust. Spherical particles in PM2.5 are dominantly composed of Fe, O and C, grain-diameters of particles range from 0.3 to 2 um. Angular particles of Fe

  17. PATRAN 2.5/EAL interface guide

    NASA Technical Reports Server (NTRS)

    Feldhaus, Winifred S.

    1994-01-01

    The PATRAN/EA interface guide describes two programs, EALPAT and PATEAL. EALPAT reads an EAL LO1 file and translates the model and results into a PATRAN 2.5 neutral file, element results file, and nodal results file. An EAL model can be color coded in PATRAN, and geometry, loads, boundary conditions, section and material properties, rigid masses, springs, and beam orientations can be plotted and debugged. EAL results can be brought into PATRAN as element or nodal quantities and displayed as deformed plots, animated shapes, color coded elements, or color filled contour plots. PATEAL converts a PATRAN 2.5 data base into an EAL runstream. Geometry, including all element types, alternate coordinate systems, material properties, section properties, loads and boundary conditions are all converted. EALPAT and PATEAL can also be used together with the PATNAS translator from PDA Engineering to convert an EAL runstream to an MSC/NASTRAN bulk data file.

  18. MCNPX version 2.5.c

    SciTech Connect

    Hendricks, J. S.

    2003-01-01

    MCNPX is a Fortran 90 Monte Carlo radiation transport computer code that transports all particles at all energies. It is a superset of MCNP4C3, and has many capabilities beyond MCNP4C3. These capabilities are summarized along with their quality guarantee and code availability. Then the user interface changes from MCNP are described. Finally, the n.ew capabilities of the latest version, MCNPX 2.5.c, are documented. Future plans and references are also provided.

  19. Monitoing PM2.5 from Space

    NASA Astrophysics Data System (ADS)

    Chu, D.; Remer, L.; Szykman, J.; Kaumfan, Y.; Neil, D.; Pierce, B.

    2003-12-01

    MODIS sensors onboard the EOS Terra and Aqua satellites launched in 1999 and 2002 provide the revolutionized perspectives to study the Earth systems. MODIS ability to derive the first aerosol product over land has advanced our understanding of aerosols into the source regions. The analysis of MODIS-derived columnar aerosol loading has shown good correlation (correlation coefficient ~0.8-0.9) with EPA PM2.5 (particulate matter with particle size less than 2.5 mm) at surface in metropolitan areas (e.g., New York City, Chicago, Houston, etc.) and also over broad regions including 11 states and Washington DC. At present, the EPA, along with Regional Planning Organizations, and state and local governments use a multitude of decision support tools to assess, control, and report the nature of air pollution related to PM. However, the current existing air quality decision processes solely rely on urban scale model and ground-based network. Using MODIS aerosol data can aid significantly in tracking the movement of pollutants, which can be used as a proxy of PM2.5 for regions without ground measurements. NASA (GSFC and LaRC) is collaborating with EPA and NOAA in providing MODIS aerosol data to benchmark PM2.5 forecast in the East US in the summer 2003. This activity is to prototype similar activities in the following years using MODIS direct broadcasting to study transport (national, international, or intercontinental) issues and assess performance effectiveness of existing air quality regulations. Improvements of MODIS aerosol algorithm are planned to achieve better spatial resolution for urban pollution and health-related studies.

  20. PM2.5 and survival among older adults: Effect modification by particulate composition

    PubMed Central

    Kioumourtzoglou, Marianthi-Anna; Austin, Elena; Koutrakis, Petros; Dominici, Francesca; Schwartz, Joel; Zanobetti, Antonella

    2015-01-01

    Background Fine particulate (PM2.5) air pollution has been consistently linked to survival, but reported effect estimates are geographically heterogeneous. Exposure to different types of particle mixtures may explain some of this variation. Methods We used k-means cluster analyses to identify cities with similar pollution profiles, (i.e. PM2.5 composition) across the US. We examined the impact of PM2.5 on survival, and its variation across clusters of cities with similar PM2.5 composition, among Medicare enrollees in 81 US cities (2000–2010). We used time-varying annual PM2.5 averages, measured at ambient central monitoring sites, as the exposure of interest. We ran by-city Cox models, adjusting for individual data on previous cardiopulmonary-related hospitalizations and stratifying by follow-up time, age, gender and race. This eliminates confounding by factors varying across cities and long-term trends, focusing on year-to-year variations of air pollution around its city-specific mean and trend. We then pooled the city-specific effects using a random effects meta-regression. In this second stage, we also assessed effect modification by cluster membership and estimated cluster-specific PM2.5 effects. Results We followed more than 19 million subjects and observed more than 6 million deaths. We found a harmful impact of annual PM2.5 concentrations on survival (HR = 1.11 [95% confidence interval = 1.01–1.23] per 10 µg/m3). This effect was modified by particulate composition, with higher effects observed in clusters containing high concentrations of nickel, vanadium and sulfate. For instance, our highest effect estimate was observed in cities with harbors in the Northwest, characterized by high nickel, vanadium and elemental carbon concentrations (1.9 [1.1–3.3]). We observed null or negative associations in clusters with high oceanic and crustal particles. Conclusions To our knowledge, this is the first study to examine the association between PM2.5 composition

  1. Phase transitions between lower and higher level management learning in times of crisis: an experimental study based on synergetics.

    PubMed

    Liening, Andreas; Strunk, Guido; Mittelstadt, Ewald

    2013-10-01

    Much has been written about the differences between single- and double-loop learning, or more general between lower level and higher level learning. Especially in times of a fundamental crisis, a transition between lower and higher level learning would be an appropriate reaction to a challenge coming entirely out of the dark. However, so far there is no quantitative method to monitor such a transition. Therefore we introduce theory and methods of synergetics and present results from an experimental study based on the simulation of a crisis within a business simulation game. Hypothesized critical fluctuations - as a marker for so-called phase transitions - have been assessed with permutation entropy. Results show evidence for a phase transition during the crisis, which can be interpreted as a transition between lower and higher level learning.

  2. Continuous higher-order sliding mode control with time-varying gain for a class of uncertain nonlinear systems.

    PubMed

    Han, Yaozhen; Liu, Xiangjie

    2016-05-01

    This paper presents a continuous higher-order sliding mode (HOSM) control scheme with time-varying gain for a class of uncertain nonlinear systems. The proposed controller is derived from the concept of geometric homogeneity and super-twisting algorithm, and includes two parts, the first part of which achieves smooth finite time stabilization of pure integrator chains. The second part conquers the twice differentiable uncertainty and realizes system robustness by employing super-twisting algorithm. Particularly, time-varying switching control gain is constructed to reduce the switching control action magnitude to the minimum possible value while keeping the property of finite time convergence. Examples concerning the perturbed triple integrator chains and excitation control for single-machine infinite bus power system are simulated respectively to demonstrate the effectiveness and applicability of the proposed approach. PMID:26920085

  3. Continuous higher-order sliding mode control with time-varying gain for a class of uncertain nonlinear systems.

    PubMed

    Han, Yaozhen; Liu, Xiangjie

    2016-05-01

    This paper presents a continuous higher-order sliding mode (HOSM) control scheme with time-varying gain for a class of uncertain nonlinear systems. The proposed controller is derived from the concept of geometric homogeneity and super-twisting algorithm, and includes two parts, the first part of which achieves smooth finite time stabilization of pure integrator chains. The second part conquers the twice differentiable uncertainty and realizes system robustness by employing super-twisting algorithm. Particularly, time-varying switching control gain is constructed to reduce the switching control action magnitude to the minimum possible value while keeping the property of finite time convergence. Examples concerning the perturbed triple integrator chains and excitation control for single-machine infinite bus power system are simulated respectively to demonstrate the effectiveness and applicability of the proposed approach.

  4. Is the general conclusion justified that higher applicable field strength results in shorter analysis time with organic solvents in CE?

    PubMed

    Téllez, Adolfo; Kenndler, Ernst

    2009-11-01

    In this paper, a widespread opinion in CE with organic solvents for the background electrolyte is critically questioned, namely that in general a shorter analysis time can be achieved due to the higher field strength applicable compared with aqueous electrolyte systems. This view, common in the literature, is based on the supposition that the conductance in organic solvents is lower than in water. Indeed in many organic solvents with higher viscosity than water lower ion mobility is observed, and higher fields can be applied in these cases. However, in this paper the problem is sharper defined and treated two-fold: (i) in all solvents conditions are such that either the same electric power is generated, or (ii) the same temperature increase is taken into account. It was shown that for the same electric power the field strength in the organic solvent can be changed to a less extent than the ionic mobility changes. As a result, the migration velocity of the analytes is lower and the analysis time is longer in most organic solvents compared with water; acetonitrile (MeCN) is an exception (in this solvent the mobilities are higher than in water). The more stringent treatment of the problem takes an equal temperature increase due to Joule heating into account rather than equal electric power. The temperature increase in the capillary depends on the thermal conductivity of the solvent, which is only about one-third of that of water for organic liquids. The consequence is that in none of the organic solvent systems a shorter analysis time can be achieved compared with water (given that the experimental conditions are comparable, e.g. zero EOF). The theoretical predictions were confirmed by measurements with water, methanol, propylenecarbonate, and MeCN as solvents.

  5. The distribution of PM10 and PM2.5 carbonaceous aerosol in Baotou, China

    NASA Astrophysics Data System (ADS)

    Zhou, Haijun; He, Jiang; Zhao, Boyi; Zhang, Lijun; Fan, Qingyun; Lü, Changwei; Dudagula; Liu, Tao; Yuan, Yinghui

    2016-09-01

    Particulate matter (PM), including PM10 and PM2.5, is one of the major impacts on air quality, visibility, climate change, earth radiation balance, and public health. Organic carbon (OC) and elemental carbon (EC) are the major components of PM. 804 samples (PM10 and PM2.5) were simultaneously collected from six urban sites covering 3 districts in Baotou, in January, April, September, and November 2014. As to a long-term study on the effects of carbonaceous aerosol, data were collected annually at Environmental Protection Agency of Baotou (EPB). The concentrations of PM10 and PM2.5, the spatial distribution and content of OC and EC, the relationship between OC and EC, and the formation of secondary organic carbon (SOC) have been investigated. The findings indicated that the concentrations of these particle matter are higher than that in US or European standards. The average concentrations of OC in PM10 and PM2.5 follow the order: January > November > April > September; and for EC in PM10 and PM2.5 follow the order: January > November > September > April. Affected by metrological factors, it was indicated that high wind speed and low relative humidity were beneficial for removal of OC and EC in January and November. Pearson correlations and cluster analysis on OC and EC concentrations in PM10 and PM2.5 with gaseous pollutants (SO2, NO2, and CO) suggested that OC shared the same emission sources with SO2 and CO from combustion, while EC's sources mainly came from vehicles exhaust and combustion which contributed to NO2 as well. The OC concentration is mainly primary in warm months, while it appears secondary in cold months in Baotou. There is a common characteristic among the cities with higher SOC in winter, wherever the coal combustion can lead to the severe pollution. This work is important for the construction of the database of OC and EC concentrations in PM10 and PM2.5 at spatial and time intervals, and it can provide scientific suggestion for similar PM

  6. Concentrations and emission factors for PM2.5 and PM10 from road traffic in Sweden

    NASA Astrophysics Data System (ADS)

    Ferm, Martin; Sjöberg, Karin

    2015-10-01

    PM10 concentrations exceed the guidelines in some Swedish cities and the limit values will likely be further reduced in the future. In order to gain more knowledge of emission factors for road traffic and concentrations of PM10 and PM2.5, existing monitoring stations in two cities, Gothenburg and Umeå, with international E-road thoroughfares, were complemented with some PM2.5 measurements. Emission factors for PM10 and PM2.5 were estimated using NOX as a tracer. Monitoring data from kerbside and urban background sites in Gothenburg during 2006-2010 and in Umeå during 2006-2012 were used. NOX emissions were estimated from the traffic flow and emission factors calculated from the HBEFA3.1 model. PM2.5 constitutes the finer part of PM10. Emissions of the coarser part of PM10 (PM10-PM2.5) are suppressed when roads are wet and show a maximum during spring when the roads dry up and studded tyres are still used. Less than 1% of the road wear caused by studded tyres give rise to airborne PM2.5-10 particles. The NOX emission factors decrease with time in the used model, due to the renewal of the vehicle fleet. However, the NOX concentrations resulting from the roads show no clear trend. The air dispersion is an important factor controlling the PM concentration near the road. The dispersion has a minimum in winter and during midnight. The average street level concentrations of PM10 and PM2.5 in Gothenburg were 21 ± 20 and 8 ± 6 μg m-3 respectively, which is 36% and 22% higher than the urban background concentrations. Despite the four times lower traffic flow in Umeå compared to Gothenburg, the average particle concentrations were very similar; 21 ± 31 and 7 ± 5 μg m-3 for PM10 and PM2.5 respectively. These concentrations were, however, 108% and 55% higher than the urban background concentrations in Umeå. The emission factors for PM10 decreased with time, and the average factor was 0.06 g km-1 vehichle-1. The emission factors for PM2.5 are very uncertain due to the

  7. Personal exposures and microenvironment concentrations of PM 2.5, VOC, NO 2 and CO in Oxford, UK

    NASA Astrophysics Data System (ADS)

    Lai, H. K.; Kendall, M.; Ferrier, H.; Lindup, I.; Alm, S.; Hänninen, O.; Jantunen, M.; Mathys, P.; Colvile, R.; Ashmore, M. R.; Cullinan, P.; Nieuwenhuijsen, M. J.

    Between 1998 and 2000 in Oxford, UK, simultaneous personal exposures and microenvironmental measurements (home indoor, home outdoor and work indoor) to fine particulate matters PM 2.5, volatile organic compounds (VOC), nitrogen dioxide (NO 2) and carbon monoxide (CO) were carried out once per person among 50 adults over a 48-h period. Thirty-seven elements in PM 2.5 and 30 different VOCs were analysed. Questionnaires were distributed to record their time-activity patterns and exposure-related information. Results showed that participants spent more time (89.5%) in all indoors than in other microenvironments. Geometric mean (GM) of personal and home indoor levels of PM 2.5, 14 elements (aluminium, arsenic, bromine, calcium, copper, iron, gallium, potassium, sodium, phosphorus, lead, selenium, silicon, titanium), total VOC (TVOC) and 8 individual compounds (nonane, decane, undecane, trimethylbenzene, toluene, benzaldehyde, alpha-pinene and d-limonene) were over 20% higher than their GM outdoor levels. Those of NO 2, 5 aromatic VOCs (benzene, o-xylene, ethylbenzene, propylbenzene, m, p-xylene) and 5 other elements (chlorine, magnesium, manganese, sulphur, zinc) were close to their GM outdoor levels. For PM 2.5 and TVOC, personal exposures and residential indoor levels (in GM) were about 2 times higher among the tobacco-smoke exposed group compared to the non-smoke exposed group, suggesting that smoking is an important determinant of these exposures. Determinants for CO were visualised by real-time monitoring, and we showed that the peak levels of personal exposure to CO were associated with smoking, cooking and transportation activities. Moderate to good correlations were only found between the personal exposures and residential indoor levels for both PM 2.5 ( r=0.60, p<0.001) and NO 2 ( r=0.47, p=0.003).

  8. A High-Order, Linear Time-Invariant Model for Application to Higher Harmonic Control and Flight Control System Interaction

    NASA Technical Reports Server (NTRS)

    Cheng, Rendy P.; Tischler, Mark B.; Celi, Roberto

    2006-01-01

    This research describes a new methodology for the extraction of a high-order, linear time invariant model, which allows the periodicity of the helicopter response to be accurately captured. This model provides the needed level of dynamic fidelity to permit an analysis and optimization of the AFCS and HHC algorithms. The key results of this study indicate that the closed-loop HHC system has little influence on the AFCS or on the vehicle handling qualities, which indicates that the AFCS does not need modification to work with the HHC system. However, the results show that the vibration response to maneuvers must be considered during the HHC design process, and this leads to much higher required HHC loop crossover frequencies. This research also demonstrates that the transient vibration responses during maneuvers can be reduced by optimizing the closed-loop higher harmonic control algorithm using conventional control system analyses.

  9. Less Time to Study, Less Well Prepared for Work, yet Satisfied with Higher Education: A UK Perspective on Links between Higher Education and the Labour Market

    ERIC Educational Resources Information Center

    Little, Brenda; Arthur, Lore

    2010-01-01

    This paper explores graduates' views on the relationship between higher education and employment. It draws on a major European study involving graduates five years after graduation and highlights similarities and differences between UK graduates' experiences and their European counterparts. Specifically, we address questions raised in the study…

  10. The vertical distribution of PM2.5 and boundary-layer structure during summer haze in Beijing

    NASA Astrophysics Data System (ADS)

    Sun, Yang; Song, Tao; Tang, Guiqian; Wang, Yuesi

    2013-08-01

    became more significant, while the low temperatures at higher altitudes facilitated the formation of organic aerosols. Sometimes, the PM2.5 levels increased due to long-range transmission of smoke plume into the residual layer. By the synchronous effect of these factors, the moisture absorption of PM2.5 in the upper layer increased, at times resulting in a "higher-top and lower-bottom" pattern of the PM2.5 distribution.

  11. 2,5-diketopiperazines as neuroprotective agents.

    PubMed

    Cornacchia, C; Cacciatore, I; Baldassarre, L; Mollica, A; Feliciani, F; Pinnen, F

    2012-01-01

    2,5-diketopiperazines are the simplest cyclic peptides found in nature, commonly biosynthesized from amino acids by different organisms, and represent a promising class of biologically active natural products. Their peculiar heterocyclic structure confers high stability against the proteolysis and constitutes a structural requirement for the active intestinal absorption. Furthermore, the diketopiperazine-based motif is considered as a novel brain shuttle for the delivery of drugs with limited ability to cross the blood-brain barrier (BBB) and can be proposed as an ideal candidate for the rational development of new therapeutic agents. Although these cyclic peptides have been known since the beginning of the 20th century, only recently have they attracted substantial interest with respect to the wide spectrum of their biological properties, including antitumor, antiviral, antifungal, antibacterial and antihyperglycemic activities. In addition to these, the most challenging function of the diketopiperazine derivatives is related with their remarkable neuroprotective and nootropic activity. The aim of the present paper is to provide an overview of the two major classes of diketopiperazines, the TRH-related and the unsaturated derivatives both characterized by a significant ability to protect against neurotoxicity in several experimental models. The neuroprotective profile of these compounds suggests that they may have a future utility in the therapy of neuronal degeneration in vivo, potentially through several different mechanisms.

  12. Higher-order time-symmetry-breaking phase transition due to meeting of an exceptional point and a Fano resonance

    NASA Astrophysics Data System (ADS)

    Tanaka, Satoshi; Garmon, Savannah; Kanki, Kazuki; Petrosky, Tomio

    2016-08-01

    We have theoretically investigated the time-symmetry-breaking phase-transition process for two discrete states coupled with a one-dimensional continuum by solving the nonlinear eigenvalue problem for the effective Hamiltonian associated with the discrete spectrum. We obtain the effective Hamiltonian with use of the Feshbach-Brillouin-Wigner projection method. Strong energy dependence of the self-energy appearing in the effective Hamiltonian plays a key role in the time-symmetry-breaking phase transition: As a result of competition in the decay process between the Van Hove singularity and the Fano resonance, the phase transition becomes a higher-order transition when both the two discrete states are located near the continuum threshold.

  13. Higher level phylogeny and the first divergence time estimation of Heteroptera (Insecta: Hemiptera) based on multiple genes.

    PubMed

    Li, Min; Tian, Ying; Zhao, Ying; Bu, Wenjun

    2012-01-01

    Heteroptera, or true bugs, are the largest, morphologically diverse and economically important group of insects with incomplete metamorphosis. However, the phylogenetic relationships within Heteroptera are still in dispute and most of the previous studies were based on morphological characters or with single gene (partial or whole 18S rDNA). Besides, so far, divergence time estimates for Heteroptera totally rely on the fossil record, while no studies have been performed on molecular divergence rates. Here, for the first time, we used maximum parsimony (MP), maximum likelihood (ML) and Bayesian inference (BI) with multiple genes (18S rDNA, 28S rDNA, 16S rDNA and COI) to estimate phylogenetic relationships among the infraorders, and meanwhile, the Penalized Likelihood (r8s) and Bayesian (BEAST) molecular dating methods were employed to estimate divergence time of higher taxa of this suborder. Major results of the present study included: Nepomorpha was placed as the most basal clade in all six trees (MP trees, ML trees and Bayesian trees of nuclear gene data and four-gene combined data, respectively) with full support values. The sister-group relationship of Cimicomorpha and Pentatomomorpha was also strongly supported. Nepomorpha originated in early Triassic and the other six infraorders originated in a very short period of time in middle Triassic. Cimicomorpha and Pentatomomorpha underwent a radiation at family level in Cretaceous, paralleling the proliferation of the flowering plants. Our results indicated that the higher-group radiations within hemimetabolous Heteroptera were simultaneously with those of holometabolous Coleoptera and Diptera which took place in the Triassic. While the aquatic habitat was colonized by Nepomorpha already in the Triassic, the Gerromorpha independently adapted to the semi-aquatic habitat in the Early Jurassic.

  14. Higher Level Phylogeny and the First Divergence Time Estimation of Heteroptera (Insecta: Hemiptera) Based on Multiple Genes

    PubMed Central

    Zhao, Ying; Bu, Wenjun

    2012-01-01

    Heteroptera, or true bugs, are the largest, morphologically diverse and economically important group of insects with incomplete metamorphosis. However, the phylogenetic relationships within Heteroptera are still in dispute and most of the previous studies were based on morphological characters or with single gene (partial or whole 18S rDNA). Besides, so far, divergence time estimates for Heteroptera totally rely on the fossil record, while no studies have been performed on molecular divergence rates. Here, for the first time, we used maximum parsimony (MP), maximum likelihood (ML) and Bayesian inference (BI) with multiple genes (18S rDNA, 28S rDNA, 16S rDNA and COI) to estimate phylogenetic relationships among the infraorders, and meanwhile, the Penalized Likelihood (r8s) and Bayesian (BEAST) molecular dating methods were employed to estimate divergence time of higher taxa of this suborder. Major results of the present study included: Nepomorpha was placed as the most basal clade in all six trees (MP trees, ML trees and Bayesian trees of nuclear gene data and four-gene combined data, respectively) with full support values. The sister-group relationship of Cimicomorpha and Pentatomomorpha was also strongly supported. Nepomorpha originated in early Triassic and the other six infraorders originated in a very short period of time in middle Triassic. Cimicomorpha and Pentatomomorpha underwent a radiation at family level in Cretaceous, paralleling the proliferation of the flowering plants. Our results indicated that the higher-group radiations within hemimetabolous Heteroptera were simultaneously with those of holometabolous Coleoptera and Diptera which took place in the Triassic. While the aquatic habitat was colonized by Nepomorpha already in the Triassic, the Gerromorpha independently adapted to the semi-aquatic habitat in the Early Jurassic. PMID:22384163

  15. Higher level phylogeny and the first divergence time estimation of Heteroptera (Insecta: Hemiptera) based on multiple genes.

    PubMed

    Li, Min; Tian, Ying; Zhao, Ying; Bu, Wenjun

    2012-01-01

    Heteroptera, or true bugs, are the largest, morphologically diverse and economically important group of insects with incomplete metamorphosis. However, the phylogenetic relationships within Heteroptera are still in dispute and most of the previous studies were based on morphological characters or with single gene (partial or whole 18S rDNA). Besides, so far, divergence time estimates for Heteroptera totally rely on the fossil record, while no studies have been performed on molecular divergence rates. Here, for the first time, we used maximum parsimony (MP), maximum likelihood (ML) and Bayesian inference (BI) with multiple genes (18S rDNA, 28S rDNA, 16S rDNA and COI) to estimate phylogenetic relationships among the infraorders, and meanwhile, the Penalized Likelihood (r8s) and Bayesian (BEAST) molecular dating methods were employed to estimate divergence time of higher taxa of this suborder. Major results of the present study included: Nepomorpha was placed as the most basal clade in all six trees (MP trees, ML trees and Bayesian trees of nuclear gene data and four-gene combined data, respectively) with full support values. The sister-group relationship of Cimicomorpha and Pentatomomorpha was also strongly supported. Nepomorpha originated in early Triassic and the other six infraorders originated in a very short period of time in middle Triassic. Cimicomorpha and Pentatomomorpha underwent a radiation at family level in Cretaceous, paralleling the proliferation of the flowering plants. Our results indicated that the higher-group radiations within hemimetabolous Heteroptera were simultaneously with those of holometabolous Coleoptera and Diptera which took place in the Triassic. While the aquatic habitat was colonized by Nepomorpha already in the Triassic, the Gerromorpha independently adapted to the semi-aquatic habitat in the Early Jurassic. PMID:22384163

  16. Chemical characteristics of PM2.5 during haze episodes in Beijing

    NASA Astrophysics Data System (ADS)

    Shen, Rongrong; Schaefer, Klaus; Suppan, Peter; Wang, Yuesi; Schnelle-Kreis, Jürgen; Shao, Longyi; Emeis, Stefan

    2014-05-01

    Haze episodes have become much more frequent in Beijing and have received more attention during the past decade because of its influences on visibility and human health. Due to the chemical characteristics and sources of haze, which are different from the normal urban aerosols, studies of haze pollution become more important for the control of air pollution in Beijing. This study aims to investigate the chemical characteristics of PM2.5 during haze episodes in Beijing in 2013 spring and the possible sources of chemical compounds during haze episodes. Two sequential High-Volume Samplers (Digitel DHA-80, Hegnau, Switzerland) were used to collect PM2.5 samples in Beijing automatically from 10 April to 8 June 2013. The inorganic elements, inorganic water-soluble ions, EC and OC of PM2.5 were analyzed by ICP-MS, IC and thermal/optical carbon analyzers respectively. Three haze episodes were found: 18 to 25 April, 3 to 9 May and 1 to 8 June. The average PM2.5 mass concentration during haze days was 140 µg m-3 while 45 µg m-3 during clear days. SO42-, NO3-, NH4+, Cl-, K+, Cu, Ni, Zn, As, Cd, Tl, Pb, EC and OC, mass concentrations increased during haze days, compared with concentrations during clear days. The main increase is that secondary inorganic pollutant mass concentrations (NO3-, SO42- and NH4+) were 6 times higher and mass percentages were 2 times higher. This indicates that the major chemical species of PM2.5 during haze episodes are originated from anthropogenic sources. NO3-, SO42- and NH4+ are basically formed by a gas-to-particle formation processes on the basis of chemical reactions of precursor gases. Mass ratio of NO3-/SO42- is widely used as an indicator to determine the importance of mobile sources and stationary sources of sulphur and nitrogen. The mass ratio of NO3-/SO42- during haze days (0.82) was higher than during clear days (0.68) suggesting that vehicle emission is an important reason for haze in Beijing. OC/EC mass ratio higher than 2 indicates

  17. Effects of day-of-week trends and vehicle types on PM2.5-bounded carbonaceous compositions.

    PubMed

    Pongpiachan, Siwatt; Kositanont, Charnwit; Palakun, Jittree; Liu, Suixin; Ho, Kin Fai; Cao, Junji

    2015-11-01

    Carbonaceous compositions of PM2.5 were measured in the heart of Bangkok from 17th November 2010 to 19th January 2012, and a data set of 94 samples was constructed. Effects of day-of-week trends and vehicle types on PM2.5-bound TC, OC, and EC were carefully investigated. In this study, OC was the most important contributor to the total PM2.5 mass concentration. The average PM2.5-bound OC content measured at CHAOS (18.8 ± 9.18 μg m(-3)) was approximately 11 times higher than at Chaumont, Switzerland (1.7 μg m(-3)), but approximately five times lower than at Xi'an, China (93.0 μg m(-3)). The application of diagnostic binary ratios of OC/EC and estimations of secondary organic carbon (SOC) coupled with autocorrelation plots (Box and Jenkins) highlight the enhanced impacts of traffic emissions, especially from diesel vehicles, on PM2.5-bound carbonaceous compositions on weekdays relative to weekends. Hierarchical cluster analysis (HCA) coupled with principal component analysis (PCA) underline the importance of diesel emissions as the primary contributors of carbonaceous aerosols, particularly during weekdays. PMID:26100727

  18. PM2.5 Population Exposure in New Delhi Using a Probabilistic Simulation Framework.

    PubMed

    Saraswat, Arvind; Kandlikar, Milind; Brauer, Michael; Srivastava, Arun

    2016-03-15

    This paper presents a Geographical Information System (GIS) based probabilistic simulation framework to estimate PM2.5 population exposure in New Delhi, India. The framework integrates PM2.5 output from spatiotemporal LUR models and trip distribution data using a Gravity model based on zonal data for population, employment and enrollment in educational institutions. Time-activity patterns were derived from a survey of randomly sampled individuals (n = 1012) and in-vehicle exposure was estimated using microenvironmental monitoring data based on field measurements. We simulated population exposure for three different scenarios to capture stay-at-home populations (Scenario 1), working population exposed to near-road concentrations during commutes (Scenario 2), and the working population exposed to on-road concentrations during commutes (Scenario 3). Simulated annual average levels of PM2.5 exposure across the entire city were very high, and particularly severe in the winter months: ∼200 μg m(-3) in November, roughly four times higher compared to the lower levels in the monsoon season. Mean annual exposures ranged from 109 μg m(-3) (IQR: 97-120 μg m(-3)) for Scenario 1, to 121 μg m(-3) (IQR: 110-131 μg m(-3)), and 125 μg m(-3) (IQR: 114-136 μ gm(-3)) for Scenarios 2 and 3 respectively. Ignoring the effects of mobility causes the average annual PM2.5 population exposure to be underestimated by only 11%. PMID:26885573

  19. Introducing conjoint analysis method into delayed lotteries studies: its validity and time stability are higher than in adjusting

    PubMed Central

    Białek, Michał; Markiewicz, Łukasz; Sawicki, Przemysław

    2015-01-01

    The delayed lotteries are much more common in everyday life than are pure lotteries. Usually, we need to wait to find out the outcome of the risky decision (e.g., investing in a stock market, engaging in a relationship). However, most research has studied the time discounting and probability discounting in isolation using the methodologies designed specifically to track changes in one parameter. Most commonly used method is adjusting, but its reported validity and time stability in research on discounting are suboptimal. The goal of this study was to introduce the novel method for analyzing delayed lotteries—conjoint analysis—which hypothetically is more suitable for analyzing individual preferences in this area. A set of two studies compared the conjoint analysis with adjusting. The results suggest that individual parameters of discounting strength estimated with conjoint have higher predictive value (Study 1 and 2), and they are more stable over time (Study 2) compared to adjusting. We discuss these findings, despite the exploratory character of reported studies, by suggesting that future research on delayed lotteries should be cross-validated using both methods. PMID:25674069

  20. A quantitative analysis of grid nudging effect on each process of PM2.5 production in the Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Jeon, Wonbae; Choi, Yunsoo; Lee, Hwa Woon; Lee, Soon-Hwan; Yoo, Jung-Woo; Park, Jaehyeong; Lee, Hyo-Jung

    2015-12-01

    This study investigated the effect of assimilated meteorological fields on simulated PM2.5 concentrations in the Korean Peninsula. Two different CMAQ simulations were conducted using base WRF run (BASE) and grid-nudged WRF run (GNG) which included a simple data assimilation method for the time period of April, 2009. The simulated PM2.5 and PM10 concentrations were compared with corresponding observations. The BASE PM2.5 concentrations were significantly underestimated at Anmyeondo (AMD) and six Air Quality Monitoring Station (AQMS) sites in Korea, but GNG showed improved agreement with in-situ measurements due to the effect of grid nudging. The grid nudging effect was dominant under the PBL height and it appeared more clearly under the unstable synoptic condition (April 5-8) than stable condition (April 9-13). Additional quantitative analysis was conducted using the Integrated Process Rate (IPR) in the CMAQ model to investigate the effect of varied meteorological fields on each PM2.5 production and destruction processes. The PM2.5 production rate by aerosol process in GNG was shown to be higher than that of BASE, especially near the source region (e.g., Eastern China). The increased temperature and decreased wind speed by grid nudging effect led to increase of aerosol production rates especially during the nighttime. The change of aerosol production rates were mainly caused by increased sulfate (SO42-) and nitrate (NO3-) production rates in the day and nighttime respectively. Also, GNG provides higher PM2.5 transport rates than BASE over the whole domain. The amount of PM2.5 scavenged by wet deposition process in GNG was smaller than that of BASE over the Yellow Sea, reflecting the decreased water vapor mixing ratio by grid nudging. Thus, it resulted in the increase of simulated PM2.5 concentrations. The results indicated that understanding the effects of grid nudging on PM2.5 concentrations is crucial to enhance the performance of PM2.5 modeling

  1. Ethyl-2, 5-dihydroxybenzoate displays dual activity by promoting osteoblast differentiation and inhibiting osteoclast differentiation.

    PubMed

    Kwon, Byeong-Ju; Lee, Mi Hee; Koo, Min-Ah; Kim, Min Sung; Seon, Gyeung Mi; Han, Jae-Jin; Park, Jong-Chul

    2016-03-11

    The interplay between bone-forming osteoblasts and bone-resorbing osteoclasts is essential for balanced bone remodeling. In this study, we evaluate the ability of ethyl-2, 5-dihyrdoxybenzoate (E-2, 5-DHB) to affect both osteoblast and osteoclast differentiation for bone regeneration. Osteogenic differentiation of human mesenchymal stem cells (hMSCs) was quantified by measuring alkaline phosphatase (ALP) activity and calcium deposition. To evaluate osteoclast differentiation, we investigated the effect of E-2, 5-DHB on RANKL-activated osteoclastogenesis in RAW 264.7 cells. E-2, 5-DHB enhanced ALP activity and inhibited RAW 264.7 cell osteoclastogenesis in vitro. To assess the in vivo activity of E-2, 5-DHB, hMSCs were delivered subcutaneosuly alone or in combination with E-2, 5-DHB in an alginate gel into the backs of nude-mice. Histological and immunohistochemical evaluation showed significantly higher calcium deposition in the E-2, 5-DHB group. Osteocalcin (OCN) was highly expressed in cells implanted in the gels containing E-2, 5-DHB. Our results suggest that E-2, 5-DHB can effectively enhance osteoblast differentiation and inhibit osteoclast differentiation both in vitro and in vivo. Understanding the dual function of E-2, 5-DHB on osteoblast and osteoclast differentiation will aid in future development of E-2, 5-DHB as a material for bone tissue engineering.

  2. Calibrating a ground-based backscatter lidar for continuous measurements of PM2.5

    NASA Astrophysics Data System (ADS)

    Pesch, Markus; Oderbolz, Daniel

    2007-10-01

    One of the main issues of atmospheric research and air quality control is the reduction of harmful particulate matter (PM) in the atmosphere. Small particles can enter the human airways and cause serious health problems such as COPD (Chronic Obstructive Pulmonary Disease), asthma or even lung cancer. Recently, interest has shifted from PM10 to finer fractions of particulate matter, e.g. PM2.5, because the health impact of finer particles is considered to be more severe. Up to now measurements of particulate matter were carried out mainly at ground level. However important atmospheric processes, i.e. particle formation, transport and vertical mixing processes, take place predominantly at higher altitudes in the planetary boundary layer. Lidar in principle provides the ability to observe these processes where they occur. The new method outlined in this paper demonstrates the use of a small sized and quite inexpensive lidar in stand-alone operation to investigate transport processes of particulate matter, and PM2.5 in particular. Continuous measurements of PM2.5 as a reference are gained with a conventional in-situ monitor, installed on a tower at an altitude of 325 m in the North of Berlin (Frohnauer Turm). These PM2.5 measurements will be compared with backscatter Lidar data (1064 nm) taken from approx. 60 m over ground up to an altitude of 15 km with a spatial resolution of 15 m. The vertical backscatter profiles at 325 m will be correlated to the concentrations obtained by the PM2,5 monitor on the tower. Both measurements have a time resolution of 180 s to observe also processes that take place at short time scales. The objective is to gain correlation functions for estimating PM2.5 concentrations from backscatter Lidar data. Such a calibrated Lidar system is a valuable instrument for environmental agencies and atmospheric research groups to observe and investigate causes of high level PM concentrations. First results show a reasonably good linear correlation

  3. Quantum reaction rate from higher derivatives of the thermal flux-flux autocorrelation function at time zero.

    PubMed

    Ceotto, Michele; Yang, Sandy; Miller, William H

    2005-01-22

    A quantum theory of thermal reaction rates is presented which may be viewed as an extension of the recently developed "quantum instanton" (QI) model [W. H. Miller, Y. Zhao, M. Ceotto, and S. Yang, J. Chem. Phys. 119, 1329 (2003)]. It is based on using higher derivatives of the flux-flux autocorrelation function C(t) (as given by Miller, Schwartz, and Tromp) at t=0 to construct a short time approximation for C(t). Tests of this theory on 1d and collinear reactions, both symmetric and asymmetric, show it to be more accurate than the original QI model, giving rate constants to approximately 5% for a wide range of temperature. PMID:15740237

  4. Quantum reaction rate from higher derivatives of the thermal flux-flux autocorrelation function at time zero

    NASA Astrophysics Data System (ADS)

    Ceotto, Michele; Yang, Sandy; Miller, William H.

    2005-01-01

    A quantum theory of thermal reaction rates is presented which may be viewed as an extension of the recently developed "quantum instanton" (QI) model [W. H. Miller, Y. Zhao, M. Ceotto, and S. Yang, J. Chem. Phys. 119, 1329 (2003)]. It is based on using higher derivatives of the flux-flux autocorrelation function C(t) (as given by Miller, Schwartz, and Tromp) at t=0 to construct a short time approximation for C(t). Tests of this theory on 1d and collinear reactions, both symmetric and asymmetric, show it to be more accurate than the original QI model, giving rate constants to ˜5% for a wide range of temperature.

  5. Time in Bed is Associated with Decreased Physical Activity and Higher BMI in Women Seeking Weight Loss Treatment.

    PubMed

    Hart, Chantelle N; Fava, Joseph L; Subak, Leslee L; Stone, Katie; Vittinghoff, Eric; Demos, Kathryn; O'Brien, Erin; Cairns, Alyssa; Wing, Rena

    2012-01-01

    Short sleep duration is associated with obesity risk. Despite calls to incorporate strategies to enhance sleep within the context of behavioral weight loss (BWL) treatment, little is known regarding the association between sleep and body mass index (BMI) among individuals presenting for BWL. Moreover, most research has focused on eating pathways linking sleep and BMI, and have not explored how sleep may impact engagement in physical activity. The purpose of the present study was to determine whether, in a sample of women seeking treatment for weight loss, there was an association between reported time in bed (TIB), higher BMI, lower physical activity, and less favorable dietary composition. Prior to randomization, 318 women completed measures of TIB, eating, and activity; weight and height were measured. Findings demonstrated that report of '6 hours or less' TIB/night was associated with higher BMI and lower reported physical activity compared to the referent (>7 to ≤ 8 hours/night). It was not associated with the number of reported calories consumed each day or with the percent of calories consumed from fat, carbohydrates or protein. Better understanding the role of sleep within the context of BWL treatment in women seems warranted.

  6. Comparison of Hourly PM2.5 Observations Between Urban and Suburban Areas in Beijing, China

    PubMed Central

    Yao, Ling; Lu, Ning; Yue, Xiafang; Du, Jia; Yang, Cundong

    2015-01-01

    Hourly PM2.5 observations collected at 12 stations over a 1-year period are used to identify variations between urban and suburban areas in Beijing. The data demonstrates a unique monthly variation form, as compared with other major cities. Urban areas suffer higher PM2.5 concentration (about 92 μg/m3) than suburban areas (about 77 μg/m3), and the average PM2.5 concentration in cold season (about 105 μg/m3) is higher than warm season (about 78 μg/m3). Hourly PM2.5 observations exhibit distinct seasonal, diurnal and day-of-week variations. The diurnal variation of PM2.5 is observed with higher concentration at night and lower value at daytime, and the cumulative growth of nighttime (22:00 p.m. in winter) PM2.5 concentration maybe due to the atmospheric stability. Moreover, annual average PM2.5 concentrations are about 18 μg/m3 higher on weekends than weekdays, consistent with driving restrictions on weekdays. Additionally, the nighttime peak in weekdays (21:00 p.m.) is one hour later than weekends (20:00 p.m.) which also shows the evidence of human activity. These observed facts indicate that the variations of PM2.5 concentration between urban and suburban areas in Beijing are influenced by complex meteorological factors and human activities. PMID:26426035

  7. Chemical characterization, the transport pathways and potential sources of PM2.5 in Shanghai: Seasonal variations

    NASA Astrophysics Data System (ADS)

    Zhao, Mengfei; Huang, Zhongsi; Qiao, Ting; Zhang, Yuankai; Xiu, Guangli; Yu, Jianzhen

    2015-05-01

    The 24-h PM2.5 samples were collected at the site of East China University of Science and Technology (ECUST) in Shanghai from 2011 to 2012, representing winter, spring, summer and autumn, respectively. And PM2.5 and its chemical components including organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), humic-like substance carbon (HULIS-C) and water-soluble ions were analyzed. The results suggested that the average PM2.5 concentrations were (70.35 ± 43.75) μg/m3, (69.76 ± 38.67) μg/m3, (51.26 ± 28.25) μg/m3 and (82.37 ± 48.70) μg/m3 in winter, spring, summer and autumn, respectively. Secondary inorganic ions (sulfate, nitrate and ammonium) were the dominant pollutants of PM2.5 in the four seasons. Total carbon (TC) was an important component explaining above 15% of PM2.5. OC/EC ratios were all above 2 ranging from 4.31 to 6.35; particularly in winter it reached the highest 6.35 which demonstrated that secondary organic carbon (SOC) should be a significant composition of PM2.5. The SOC calculated based on the OC/EC ratio method had stronger correlation with WSOC in summer and autumn (summer: R2 = 0.73 and autumn: R2 = 0.75). The HULIS-C and SOC most significantly correlated in autumn (R2 = 0.83). The data showed that PM2.5 atmospheric aerosols were more acidic in autumn and the concentrations of PM2.5 and its chemical components were much higher. Factor analysis (FA), cluster analysis of air mass back trajectories, potential source contribution function (PSCF) model and concentration weighted trajectory (CWT) model were used to investigate the transport pathways and identify potential source areas of PM2.5 in different seasons. FA identified various sources of PM2.5: secondary aerosol reactions, the aged sea salts and road dusts. The results of cluster analysis, PSCF model and CWT model demonstrated that the local sources in the Yangtze River Delta Region (YRDR) made significant contributions to PM2.5. During winter and autumn long-time

  8. Heterogeneous 2.5D integration on through silicon interposer

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaowu; Lin, Jong Kai; Wickramanayaka, Sunil; Zhang, Songbai; Weerasekera, Roshan; Dutta, Rahul; Chang, Ka Fai; Chui, King-Jien; Li, Hong Yu; Wee Ho, David Soon; Ding, Liang; Katti, Guruprasad; Bhattacharya, Suryanarayana; Kwong, Dim-Lee

    2015-06-01

    Driven by the need to reduce the power consumption of mobile devices, and servers/data centers, and yet continue to deliver improved performance and experience by the end consumer of digital data, the semiconductor industry is looking for new technologies for manufacturing integrated circuits (ICs). In this quest, power consumed in transferring data over copper interconnects is a sizeable portion that needs to be addressed now and continuing over the next few decades. 2.5D Through-Si-Interposer (TSI) is a strong candidate to deliver improved performance while consuming lower power than in previous generations of servers/data centers and mobile devices. These low-power/high-performance advantages are realized through achievement of high interconnect densities on the TSI (higher than ever seen on Printed Circuit Boards (PCBs) or organic substrates), and enabling heterogeneous integration on the TSI platform where individual ICs are assembled at close proximity (<1 mm separation) compared with several centimeters on a typical PCB. In this paper, we have outlined the benefits of adopting 2.5D TSI technology and also highlighted the current day approaches to implement this technology in Si fabrication facilities, and in assembly/packaging factories. While the systems and devices that power the mobile society benefit from exploiting advantages of 2.5D integration on TSI, there do exist surmountable challenges that need to be addressed for this relatively new technology to be used in high volume production of next generation semiconductor devices. The key areas of focus and challenges include: Technology planning and design-execution that are necessary for harnessing 2.5D TSI for building systems, processing flow for the fabrication of 100 μm thick TSI at acceptable costs, manufacturing flow for assembling multiple ICs on a 100 μm thick TSI in a repeatable, and reliable manner, thermo-mechanical analysis and optimization for addressing warpage issues, and thermal

  9. Energy-momentum conserving higher-order time integration of nonlinear dynamics of finite elastic fiber-reinforced continua

    NASA Astrophysics Data System (ADS)

    Erler, Norbert; Groß, Michael

    2015-05-01

    Since many years the relevance of fibre-reinforced polymers is steadily increasing in fields of engineering, especially in aircraft and automotive industry. Due to the high strength in fibre direction, but the possibility of lightweight construction, these composites replace more and more traditional materials as metals. Fibre-reinforced polymers are often manufactured from glass or carbon fibres as attachment parts or from steel or nylon cord as force transmission parts. Attachment parts are mostly subjected to small strains, but force transmission parts usually suffer large deformations in at least one direction. Here, a geometrically nonlinear formulation is necessary. Typical examples are helicopter rotor blades, where the fibres have the function to stabilize the structure in order to counteract large centrifugal forces. For long-run analyses of rotor blade deformations, we have to apply numerically stable time integrators for anisotropic materials. This paper presents higher-order accurate and numerically stable time stepping schemes for nonlinear elastic fibre-reinforced continua with anisotropic stress behaviour.

  10. Pattern formations in miscellaneous mixtures of Bose-Einstein condensates and the higher-dimensional time-gated Manakov system

    SciTech Connect

    Kuetche, Victor K.; Bouetou, Thomas B.; Kofane, Timoleon C.; Moubissi, Alain B.; Porsezian, K.

    2010-11-15

    In this article, we investigate the structure and dynamics of miscellaneous mixtures of Bose-Einstein condensates confined within a time-independent anisotropic parabolic trap potential. In the zero-temperature mean-field approximation leading to coupled Gross-Pitaevskii equations for the macroscopic wave functions of the condensates, we show that these equations can be mapped onto the higher-dimensional time-gated Manakov system up to a first-order of accuracy. Paying particular attention to two-species mixtures and looking forward deriving a panel of miscellaneous excitations to the above equations, we analyze the singularity structure of the system by means of Weiss et al.'s [J. Weiss, M. Tabor, and G. Carnevale, J. Math. Phys. 24, 522 (1983); 25, 13 (1984).] methodology and provide its general Lax representation. As a result, we unearth a typical spectrum of localized and periodic coherent patterns while depicting elastic and nonelastic interactions among such structures alongside the splitting and resonance phenomena occurring during their motion.

  11. A novel Fast Gas Chromatography based technique for higher time resolution measurements of speciated monoterpenes in air

    NASA Astrophysics Data System (ADS)

    Jones, C. E.; Kato, S.; Nakashima, Y.; Kajii, Y.

    2013-12-01

    Biogenic emissions supply the largest fraction of non-methane volatile organic compounds (VOC) from the biosphere to the atmospheric boundary layer, and typically comprise a complex mixture of reactive terpenes. Due to this chemical complexity, achieving comprehensive measurements of biogenic VOC (BVOC) in air within a satisfactory time resolution is analytically challenging. To address this, we have developed a novel, fully automated Fast Gas Chromatography (Fast-GC) based technique to provide higher time resolution monitoring of monoterpenes (and selected other C9-C15 terpenes) during plant emission studies and in ambient air. To our knowledge, this is the first study to apply a Fast-GC based separation technique to achieve quantification of terpenes in air. Three chromatography methods have been developed for atmospheric terpene analysis under different sampling scenarios. Each method facilitates chromatographic separation of selected BVOC within a significantly reduced analysis time compared to conventional GC methods, whilst maintaining the ability to quantify individual monoterpene structural isomers. Using this approach, the C10-C15 BVOC composition of single plant emissions may be characterised within a ~ 14 min analysis time. Moreover, in situ quantification of 12 monoterpenes in unpolluted ambient air may be achieved within an ~ 11 min chromatographic separation time (increasing to ~ 19 min when simultaneous quantification of multiple oxygenated C9-C10 terpenoids is required, and/or when concentrations of anthropogenic VOC are significant). This corresponds to a two- to fivefold increase in measurement frequency compared to conventional GC methods. Here we outline the technical details and analytical capability of this chromatographic approach, and present the first in situ Fast-GC observations of 6 monoterpenes and the oxygenated BVOC linalool in ambient air. During this field deployment within a suburban forest ~ 30 km west of central Tokyo, Japan, the

  12. Metal composition of ambient PM2.5 influences severity of allergic airways disease in mice.

    PubMed Central

    Gavett, Stephen H; Haykal-Coates, Najwa; Copeland, Lisa B; Heinrich, Joachim; Gilmour, M Ian

    2003-01-01

    Children living in Hettstedt in eastern Germany have been reported to have a higher prevalence of sensitization to common aeroallergens than another cohort living in the neighboring city of Zerbst; these differences correlated with the presence of industrial air pollution. Samples of fine particulate matter (< 2.5 micro m aerodynamic diameter; PM(2.5)) collected in Hettstedt in 1999 had several-fold higher levels of zinc, magnesium, lead, copper, and cadmium than samples from Zerbst. To determine if the results from epidemiologic studies could be repeated in an animal model, we administered PM(2.5) from Hettstedt and Zerbst to ovalbumin-allergic mice. In Balb/c mice, PM(2.5) from Hettstedt, but not PM(2.5) from Zerbst or control filter extract, caused a significant increase in immediate responses to ovalbumin challenge when aspirated 2 hr before challenge, but not when aspirated immediately before sensitization 2 weeks earlier. Antigen-specific IgE was increased by Hettstedt PM(2.5) whether administered before sensitization or challenge. Airway responsiveness to methacholine aerosol and lung inflammatory cell numbers were significantly increased only in allergic mice exposed to Hettstedt PM(2.5) before challenge. Both Hettstedt and Zerbst PM(2.5) significantly increased lung injury parameters and proinflammatory cytokines. These results are consistent with epidemiologic findings and show that metal composition of ambient PM(2.5) influences the severity of allergic respiratory disease. PMID:12948886

  13. Particulate matter (PM2.5) and carbon monoxide from secondhand smoke outside bars and restaurants in downtown Athens, Georgia.

    PubMed

    St Helen, Gideon; Hall, Daniel B; Kudon, Louis H; Pearce, John; Baptiste, Shanece; Ferguson, Sylvia; Green, Tiffany; Naeher, Luke P

    2011-10-01

    In the study described in this article, the authors' objective was to measure particles < or = 2.5 microm in aerodynamic diameter (PM2.5) and carbon monoxide (CO) in outdoor waiting areas and patios of restaurants and bars in downtown Athens, Georgia, where indoor smoking is banned. The authors also wanted to investigate whether the measured concentrations are directly associated with the number of cigarettes lit in these settings. Real-time PM2.5 and CO were monitored on four summer weekend afternoons/evenings in outdoor waiting areas or patios at five locations in Athens. In addition, smokers and pedestrians present or passing and motorized vehicles passing each sampling location were counted. PM2.5 levels were significantly higher than levels at the control location (all p-values > .001). Carbon monoxide levels outside the restaurant and bar sites did not differ significantly from the control. The results of the authors' study indicate that (1) secondhand smoke (SHS) leads to significant increases in PM2.5 outside of restaurants and bars; and (2) although CO can be used as a proxy for SHS in these outdoor environments, its levels remain relatively low.

  14. Occupational Exposure to PM2.5 and Incidence of Ischemic Heart Disease

    PubMed Central

    Petersen, Maya; Costello, Sadie; Noth, Elizabeth M.; Hammond, Katherine; Cullen, Mark; van der Laan, Mark; Eisen, Ellen

    2015-01-01

    Background: We investigated the incidence of ischemic heart disease (IHD) in relation to accumulated exposure to particulate matter (PM) in a cohort of aluminum workers. We adjusted for time varying confounding characteristic of the healthy worker survivor effect, using a recently introduced method for the estimation of causal target parameters. Methods: Applying longitudinal targeted minimum loss-based estimation, we estimated the difference in marginal cumulative risk of IHD in the cohort comparing counterfactual outcomes if always exposed above to always exposed below a PM2.5 exposure cut-off. Analyses were stratified by sub-cohort employed in either smelters or fabrication facilities. We selected two exposure cut-offs a priori, at the median and 10th percentile in each sub-cohort. Results: In smelters, the estimated IHD risk difference after 15 years of accumulating PM2.5 exposure during follow-up was 2.9% (0.6%, 5.1%) using the 10th percentile cut-off of 0.10 mg/m3. For fabrication workers, the difference was 2.5% (0.8%, 4.1%) at the 10th percentile of 0.06 mg/m3. Using the median exposure cut-off, results were similar in direction but smaller in size. We present marginal incidence curves describing the cumulative risk of IHD over the course of follow-up for each sub-cohort under each intervention regimen. Conclusions: The accumulation of exposure to PM2.5 appears to result in higher risks of IHD in both aluminum smelter and fabrication workers. This represents the first longitudinal application of targeted minimum loss-based estimation, a method for generating doubly robust semi-parametric efficient substitution estimators of causal parameters, in the fields of occupational and environmental epidemiology. PMID:26079662

  15. Black Carbon and Particulate Matter (PM2.5) Concentrations in New York City’s Subway Stations

    PubMed Central

    2015-01-01

    The New York City (NYC) subway is the main mode of transport for over 5 million passengers on an average weekday. Therefore, airborne pollutants in the subway stations could have a significant impact on commuters and subway workers. This study looked at black carbon (BC) and particulate matter (PM2.5) concentrations in selected subway stations in Manhattan. BC and PM2.5 levels were measured in real time using a Micro-Aethalometer and a PDR-1500 DataRAM, respectively. Simultaneous samples were also collected on quartz filters for organic and elemental carbon (OC/EC) analysis and on Teflon filters for gravimetric and trace element analysis. In the underground subway stations, mean real time BC concentrations ranged from 5 to 23 μg/m3, with 1 min average peaks >100 μg/m3, while real time PM2.5 levels ranged from 35 to 200 μg/m3. Mean EC levels ranged from 9 to 12.5 μg/m3. At street level on the same days, the mean BC and PM2.5 concentrations were below 3 and 10 μg/m3, respectively. This study shows that both BC soot and PM levels in NYC’s subways are considerably higher than ambient urban street levels and that further monitoring and investigation of BC and PM subway exposures are warranted. PMID:25409007

  16. Retrospective prediction of intraurban spatiotemporal distribution of PM2.5 in Taipei

    NASA Astrophysics Data System (ADS)

    Hwa-Lung, Yu; Chih-Hsin, Wang

    2010-08-01

    Numerous studies have shown that fine airborne particulate matter particles (PM2.5) are more dangerous to human health than coarse particles, e.g. PM10. The assessment of the impacts to human health or ecological effects by long-term PM2.5 exposure is often limited by lack of PM2.5 measurements. In Taipei, PM2.5 was not systematically observed until August, 2005. Taipei is the largest metropolitan area in Taiwan, where a variety of industrial and traffic emissions are continuously generated and distributed across space and time. PM-related data, i.e., PM10 and Total Suspended Particles (TSP) are independently systematically collected by different central and local government institutes. In this study, the retrospective prediction of spatiotemporal distribution of monthly PM2.5 over Taipei will be performed by using Bayesian Maximum Entropy method (BME) to integrate (a) the spatiotemporal dependence among PM measurements (i.e. PM10, TSP, and PM2.5), (b) the site-specific information of PM measurements which can be certain or uncertain information, and (c) empirical evidence about the PM2.5/PM10 and PM10/TSP ratios. The performance assessment of the retrospective prediction for the spatiotemporal distribution of PM2.5 was performed over space and time during 2003-2004 by comparing the posterior pdf of PM2.5 with the observations. Results show that the incorporation of PM10 and TSP observations by BME method can effectively improve the spatiotemporal PM2.5 estimation in the sense of lower mean and standard deviation of estimation errors. Moreover, the spatiotemporal retrospective prediction with PM2.5/PM10 and PM2.5/TSP ratios can provide good estimations of the range of PM2.5 levels over space and time during 2003-2004 in Taipei.

  17. Photoionization mass spectrometric measurements of initial reaction pathways in low-temperature oxidation of 2,5-dimethylhexane

    DOE PAGES

    Rotavera, Brandon; Zádor, Judit; Welz, Oliver; Sheps, Leonid; Scheer, Adam M.; Savee, John D.; Akbar Ali, Mohamad; Lee, Taek Soon; Simmons, Blake A.; Osborn, David L.; et al

    2014-09-19

    The product formation from R + O2 reactions relevant to low-temperature autoignition chemistry was studied for 2,5-dimethylhexane, a symmetrically branched octane isomer, at 550 and 650 K using Cl-atom initiated oxidation and multiplexed photoionization mass spectrometry (MPIMS). The interpretation of time- and photon-energy-resolved mass spectra led to three specific results important to characterizing the initial oxidation steps: (1) quantified isomer-resolved branching ratios for HO2 + alkene channels; (2) 2,2,5,5-tetramethyltetrahydrofuran is formed in substantial yield from addition of O2 to tertiary 2,5-dimethylhex-2-yl followed by isomerization of the resulting ROO adduct to tertiary hydroperoxyalkyl (QOOH) and exhibits a positive dependence on temperaturemore » over the range covered leading to a higher flux relative to aggregate cyclic ether yield. The higher relative flux is explained by a 1,5-hydrogen atom shift reaction that converts the initial primary alkyl radical (2,5-dimethylhex-1-yl) to the tertiary alkyl radical 2,5-dimethylhex-2-yl, providing an additional source of tertiary alkyl radicals. Furthermore, quantum-chemical and master-equation calculations of the unimolecular decomposition of the primary alkyl radical reveal that isomerization to the tertiary alkyl radical is the most favorable pathway, and is favored over O2-addition at 650 K under the conditions herein. The isomerization pathway to tertiary alkyl radicals therefore contributes an additional mechanism to 2,2,5,5-tetramethyltetrahydrofuran formation; (3) carbonyl species (acetone, propanal, and methylpropanal) consistent with β-scission of QOOH radicals were formed in significant yield, indicating unimolecular QOOH decomposition into carbonyl + alkene + OH.« less

  18. Photoionization mass spectrometric measurements of initial reaction pathways in low-temperature oxidation of 2,5-dimethylhexane

    SciTech Connect

    Rotavera, Brandon; Zádor, Judit; Welz, Oliver; Sheps, Leonid; Scheer, Adam M.; Savee, John D.; Akbar Ali, Mohamad; Lee, Taek Soon; Simmons, Blake A.; Osborn, David L.; Violi, Angela; Taatjes, Craig A.

    2014-09-19

    The product formation from R + O2 reactions relevant to low-temperature autoignition chemistry was studied for 2,5-dimethylhexane, a symmetrically branched octane isomer, at 550 and 650 K using Cl-atom initiated oxidation and multiplexed photoionization mass spectrometry (MPIMS). The interpretation of time- and photon-energy-resolved mass spectra led to three specific results important to characterizing the initial oxidation steps: (1) quantified isomer-resolved branching ratios for HO2 + alkene channels; (2) 2,2,5,5-tetramethyltetrahydrofuran is formed in substantial yield from addition of O2 to tertiary 2,5-dimethylhex-2-yl followed by isomerization of the resulting ROO adduct to tertiary hydroperoxyalkyl (QOOH) and exhibits a positive dependence on temperature over the range covered leading to a higher flux relative to aggregate cyclic ether yield. The higher relative flux is explained by a 1,5-hydrogen atom shift reaction that converts the initial primary alkyl radical (2,5-dimethylhex-1-yl) to the tertiary alkyl radical 2,5-dimethylhex-2-yl, providing an additional source of tertiary alkyl radicals. Furthermore, quantum-chemical and master-equation calculations of the unimolecular decomposition of the primary alkyl radical reveal that isomerization to the tertiary alkyl radical is the most favorable pathway, and is favored over O2-addition at 650 K under the conditions herein. The isomerization pathway to tertiary alkyl radicals therefore contributes an additional mechanism to 2,2,5,5-tetramethyltetrahydrofuran formation; (3) carbonyl species (acetone, propanal, and methylpropanal) consistent with β-scission of QOOH radicals were formed in significant yield, indicating unimolecular QOOH decomposition into carbonyl + alkene + OH.

  19. Photoionization mass spectrometric measurements of initial reaction pathways in low-temperature oxidation of 2,5-dimethylhexane.

    PubMed

    Rotavera, Brandon; Zádor, Judit; Welz, Oliver; Sheps, Leonid; Scheer, Adam M; Savee, John D; Akbar Ali, Mohamad; Lee, Taek Soon; Simmons, Blake A; Osborn, David L; Violi, Angela; Taatjes, Craig A

    2014-11-01

    Product formation from R + O2 reactions relevant to low-temperature autoignition chemistry was studied for 2,5-dimethylhexane, a symmetrically branched octane isomer, at 550 and 650 K using Cl-atom initiated oxidation and multiplexed photoionization mass spectrometry (MPIMS). Interpretation of time- and photon-energy-resolved mass spectra led to three specific results important to characterizing the initial oxidation steps: (1) quantified isomer-resolved branching ratios for HO2 + alkene channels; (2) 2,2,5,5-tetramethyltetrahydrofuran is formed in substantial yield from addition of O2 to tertiary 2,5-dimethylhex-2-yl followed by isomerization of the resulting ROO adduct to tertiary hydroperoxyalkyl (QOOH) and exhibits a positive dependence on temperature over the range covered leading to a higher flux relative to aggregate cyclic ether yield. The higher relative flux is explained by a 1,5-hydrogen atom shift reaction that converts the initial primary alkyl radical (2,5-dimethylhex-1-yl) to the tertiary alkyl radical 2,5-dimethylhex-2-yl, providing an additional source of tertiary alkyl radicals. Quantum-chemical and master-equation calculations of the unimolecular decomposition of the primary alkyl radical reveal that isomerization to the tertiary alkyl radical is the most favorable pathway, and is favored over O2-addition at 650 K under the conditions herein. The isomerization pathway to tertiary alkyl radicals therefore contributes an additional mechanism to 2,2,5,5-tetramethyltetrahydrofuran formation; (3) carbonyl species (acetone, propanal, and methylpropanal) consistent with β-scission of QOOH radicals were formed in significant yield, indicating unimolecular QOOH decomposition into carbonyl + alkene + OH.

  20. Study of Interpolated Timing Recovery Phase-Locked Loop with Linearly Constrained Adaptive Prefilter for Higher-Density Optical Disc

    NASA Astrophysics Data System (ADS)

    Kajiwara, Yoshiyuki; Shiraishi, Junya; Kobayashi, Shoei; Yamagami, Tamotsu

    2009-03-01

    A digital phase-locked loop (PLL) with a linearly constrained adaptive filter (LCAF) has been studied for higher-linear-density optical discs. LCAF has been implemented before an interpolated timing recovery (ITR) PLL unit in order to improve the quality of phase error calculation by using an adaptively equalized partial response (PR) signal. Coefficient update of an asynchronous sampled adaptive FIR filter with a least-mean-square (LMS) algorithm has been constrained by a projection matrix in order to suppress the phase shift of the tap coefficients of the adaptive filter. We have developed projection matrices that are suitable for Blu-ray disc (BD) drive systems by numerical simulation. Results have shown the properties of the projection matrices. Then, we have designed the read channel system of the ITR PLL with an LCAF model on the FPGA board for experiments. Results have shown that the LCAF improves the tilt margins of 30 gigabytes (GB) recordable BD (BD-R) and 33 GB BD read-only memory (BD-ROM) with a sufficient LMS adaptation stability.

  1. Compositional characterization of PM 2.5 emitted from in-use diesel vehicles

    NASA Astrophysics Data System (ADS)

    Kim Oanh, Nguyen Thi; Thiansathit, Worrarat; Bond, Tami C.; Subramanian, R.; Winijkul, Ekbordin; Paw-armart, Ittipol

    2010-01-01

    In Asian developing countries diesel vehicles contribute significantly to urban air pollution. The emission factors (EF) and exhaust gas composition of these vehicles may be different from those in the US and Europe, where most emission measurements are taken. This study focuses on the fine particulate matter (PM 2.5) emission from in-use diesel vehicles in Bangkok, with the goal of providing EF and source profiles that are more appropriate for developing countries. The chassis dynamometer test results for 93 vehicles, including 39 light duty (LD) and 54 heavy duty (HD) of the age models between 1972 and 2005, are presented. PM EF are lower for vehicles of newer year models, consistent with the implementation of engine standards. The average PM 2.5 EF of 0.23 g km -1 for LD, and 1.76 g km -1 for HD trucks and buses are generally higher than the literature reported values. Old HD trucks produce the highest PM EF of above 3 g km -1. Black carbon (BC), measured by an optical method, is well correlated with elemental carbon (EC) by TOT, but is consistently about 1.7 times higher. Between the LD and HD fleets, there is no significant difference in the fractional composition (BC, EC, OC, water soluble ions and elements) of emitted PM 2.5. The composite source profile, weighted against the fleet composition and the vehicle km travelled (VKT) for the city has an average OC of 19%, EC of 47%, and sulfate of 2%, which are close to those reported for 1980s US diesel vehicles.

  2. Estimating Causal Effects of Long-Term PM2.5 Exposure on Mortality in New Jersey

    PubMed Central

    Wang, Yan; Kloog, Itai; Coull, Brent A.; Kosheleva, Anna; Zanobetti, Antonella; Schwartz, Joel D.

    2016-01-01

    Background: Many studies have reported the associations between long-term exposure to PM2.5 and increased risk of death. However, to our knowledge, none has used a causal modeling approach or controlled for long-term temperature exposure, and few have used a general population sample. Objective: We estimated the causal effects of long-term PM2.5 exposure on mortality and tested the effect modifications by seasonal temperatures, census tract–level socioeconomic variables, and county-level health conditions. Methods: We applied a variant of the difference-in-differences approach, which serves to approximate random assignment of exposure across the population and hence estimate a causal effect. Specifically, we estimated the association between long-term exposure to PM2.5 and mortality while controlling for geographical differences using dummy variables for each census tract in New Jersey, a state-wide time trend using dummy variables for each year from 2004 to 2009, and mean summer and winter temperatures for each tract in each year. This approach assumed that no variable changing differentially over time across space other than seasonal temperatures confounded the association. Results: For each interquartile range (2 μg/m3) increase in annual PM2.5, there was a 3.0% [95% confidence interval (CI): 0.2, 5.9%] increase in all natural-cause mortality for the whole population, with similar results for people > 65 years old [3.5% (95% CI: 0.1, 6.9%)] and people ≤ 65 years old [3.1% (95% CI: –1.8, 8.2%)]. The mean summer temperature and the mean winter temperature in a census tract significantly modified the effects of long-term exposure to PM2.5 on mortality. We observed a higher percentage increase in mortality associated with PM2.5 in census tracts with more blacks, lower home value, or lower median income. Conclusions: Under the assumption of the difference-in-differences approach, we identified a causal effect of long-term PM2.5 exposure on mortality that was

  3. Emission characteristics of carboxylates in PM2.5 from incense burning with the effect of light on acetate

    NASA Astrophysics Data System (ADS)

    Kuo, Su-Ching; Tsai, Ying I.; Sopajaree, Khajornsak

    2016-08-01

    Incense burning produces potentially harmful particulate matter. In this study we investigated the emissions of PM2.5 and gaseous acetic acid from four brands of traditional incense; Liao and Shang Lao Shan (SLS), sold in Taiwan, and Thai Yellow (Thai Y) and Thai Black (Thai B), sold in Thailand. Additionally, photochemical reactions of PM2.5 carboxylates emitted from incense burning were studied via a simulated light experiment. The average PM2.5 mass emission factor of each incense type was inversely correlated with the ash production of that incense. The Thailand incense carboxylate emissions were markedly higher than the Taiwan incense. Acetate accounted for 87.46% of total carboxylate emissions, with acetate emitted from the Thailand incense 1.26 times higher than from the Taiwan incense. Phthalate was detected in the PM2.5, indicating the presence of plasticizer. Concentrations of PM2.5 acetate, formate, pyruvate, glutarate, succinate, fumarate and tartarate were reduced in simulated light (51.5%-97.1% of those under dark), indicating that these seven types of carboxylate are easily photodegradable. In contrast, malonate, maleate, oxalate and phthalate concentrations in light were 1.17-1.84 times higher than in darkness, indicating photochemical reactions contribute to the formation of these species. The formation of the low-molecular weight dicarboxylates oxalate and malonate was most noticeable. Acetic acid, highly irritating to the respiratory system and skin, was present at high levels for all four incense types, as shown by the gaseous acetic acid/PM2.5 acetate ratios of 1.03-3.61. Burning incense indoors can generate high concentrations of PM2.5 acetate that increases the risks of respiratory and contact irritation, particularly when burning the Thailand incense. Moreover, burning incense in poorly ventilated, dimly lit indoor areas (e.g., temples and homes) can markedly increase the risk of irritation because the gaseous acetic acid is not degraded as

  4. Seasonal variability of PM2.5 composition and sources in the Klang Valley urban-industrial environment

    NASA Astrophysics Data System (ADS)

    Amil, Norhaniza; Talib Latif, Mohd; Firoz Khan, Md; Mohamad, Maznorizan

    2016-04-01

    This study investigates the fine particulate matter (PM2.5) variability in the Klang Valley urban-industrial environment. In total, 94 daily PM2.5 samples were collected during a 1-year campaign from August 2011 to July 2012. This is the first paper on PM2.5 mass, chemical composition and sources in the tropical environment of Southeast Asia, covering all four seasons (distinguished by the wind flow patterns) including haze events. The samples were analysed for various inorganic components and black carbon (BC). The chemical compositions were statistically analysed and the temporal aerosol pattern (seasonal) was characterised using descriptive analysis, correlation matrices, enrichment factor (EF), stoichiometric analysis and chemical mass closure (CMC). For source apportionment purposes, a combination of positive matrix factorisation (PMF) and multi-linear regression (MLR) was employed. Further, meteorological-gaseous parameters were incorporated into each analysis for improved assessment. In addition, secondary data of total suspended particulate (TSP) and coarse particulate matter (PM10) sampled at the same location and time with this study (collected by Malaysian Meteorological Department) were used for PM ratio assessment. The results showed that PM2.5 mass averaged at 28 ± 18 µg m-3, 2.8-fold higher than the World Health Organisation (WHO) annual guideline. On a daily basis, the PM2.5 mass ranged between 6 and 118 µg m-3 with the daily WHO guideline exceeded 43 % of the time. The north-east (NE) monsoon was the only season with less than 50 % sample exceedance of the daily WHO guideline. On an annual scale, PM2.5 mass correlated positively with temperature (T) and wind speed (WS) but negatively with relative humidity (RH). With the exception of NOx, the gases analysed (CO, NO2, NO and SO2) were found to significantly influence the PM2.5 mass. Seasonal variability unexpectedly showed that rainfall, WS and wind direction (WD) did not significantly correlate

  5. Potentiation of 2,5-hexanedione neurotoxicity by methyl ethyl ketone

    SciTech Connect

    Ralston, W.H.; Hilderbrand, R.L.; Uddin, D.E.; Andersen, M.E.; Gardier, R.W.

    1985-11-01

    Chronic oral administration of a combination of 2.2 mmol methyl ethyl ketone (MEK) and 2.2 mmol 2,5-hexanedione (2,5-HD)/kg/day, 5 days/week resulted in more rapid onset of motor deficits than did chronic dosing with 2.2 mmol 2,5-HD/kg/day alone. In kinetic studies blood time courses of 2,5-HD were determined in rats in the presence and absence of MEK. Concomitant administration of MEK reduced blood 2,5-HD clearance and increased the area under the curve (AUC) for the blood 2,5-HD. In companion experiments with 2,5-(1,6-/sup 14/C)HD as a tracer, neural and nonneural tissues were examined 72 hr following the last treatment at Weeks 1, 2, and 3 of chronic administration of 2,5-HD alone or in combination with an equimolar dose of MEK. Rats treated with 2,5-(/sup 14/C)HD alone or in combination with MEK demonstrated no difference in total or trichloroacetic acid-precipitable radioactivity in blood, in liver homogenates, or in neurofilament-enriched fractions from sciatic nerve and spinal cord. The data support a suggestion that the potentiation of hexacarbon neurotoxicity by MEK is the result of the persistence of the neurotoxic metabolite in the blood and not the enhanced metabolism of parent hexacarbon to 2,5-HD.

  6. Structural characterization of native high-methoxylated pectin using nuclear magnetic resonance spectroscopy and ultraviolet matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Comparative use of 2,5-dihydroxybenzoic acid and nor-harmane as UV-MALDI matrices.

    PubMed

    Monge, María Eugenia; Negri, R Martín; Kolender, Adriana A; Erra-Balsells, Rosa

    2007-01-01

    The successful analysis by ultraviolet matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (UV-MALDI-TOF MS) of native and hydrolyzed high-methoxylated pectin samples is described. In order to find the optimal conditions for UV-MALDI-TOF MS analysis several experimental variables were studied such as: different UV-MALDI matrices (nor-harmane, 2,5-dihydroxybenzoic acid), sample preparation methods (mixture, sandwich), inorganic salt addition (doping salts, NaCl, KCl, NH(4)Cl), ion mode (positive, negative), linear and reflectron mode, etc. nor-Harmane has never been used as a UV-MALDI matrix for the analysis of pectins but its use avoids pre-treatment of the sample, such as an enzymatic digestion or an acid hydrolysis, and there is no need to add salts, making the analysis easier and faster. This study suggested an alternative way of analyzing native high-methoxylated pectins, with UV-MALDI-TOF MS, by using nor-harmane as the matrix in negative ion mode. The analysis by (1)H and (13)C nuclear magnetic resonance (NMR) spectroscopy of the native and hydrolyzed pectin is also briefly described.

  7. Risk assessment of non-dietary exposure to polycyclic aromatic hydrocarbons (PAHs) via house PM2.5, TSP and dust and the implications from human hair

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Huang, Min-juan; Chan, Chuen-Yu; Cheung, Kwai Chung; Wong, Ming Hung

    2013-07-01

    To evaluate the cancer risk due to non-dietary PAHs exposure in home environment (inhalation and ingestion), exposure to fine particles (PM2.5) and polycyclic aromatic hydrocarbons (PAHs) of PM2.5, total suspend particles (TSP) and dust in homes at two urban centers of Pearl River Delta were assessed. House PM2.5 bound PAHs in Guangzhou (GZ) ranged from 10.0 to 61.9 ng m-3 and 0.72 to 8.15 ng m-3 in Hong Kong (HK). PAH profiles found in PM2.5, TSP and dust were different than that in hair (dominated by Nap and Phe). Pyr and Flu in house dust significantly correlated with that in hair (r = 0.69; 0.55, p < 0.05) but no correlation was found between PAHs in hair and PM2.5. High correlation coefficients (r2 = 0.97/0.95, p < 0.01) were noted between dibenzo(a,h)anthracene (DBA) and Toxicity Equivalent Concentrations (TEQs) of dust and PM2.5. The lung cancer risks based on PM2.5 bound PAHs exposure in houses of GZ (10-5-10-4) were significantly higher than those of HK (10-6-10-5), which were also significantly higher than the cancer risks associated with house dust intake (10-7-10-5) in GZ. PAHs exposure via non-dietary route (PM2.5 and dust) was found to be 1-3 times higher than fish consumption for children and contributed to 52-76% of total PAHs intake for children and 24-50% for adults in GZ.

  8. 42 CFR 2.5 - Reports of violations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Reports of violations. 2.5 Section 2.5 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL PROVISIONS CONFIDENTIALITY OF ALCOHOL AND DRUG ABUSE PATIENT RECORDS Introduction § 2.5 Reports of violations. (a) The report...

  9. 10 CFR 960.4-2-5 - Erosion.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Erosion. 960.4-2-5 Section 960.4-2-5 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Postclosure Guidelines § 960.4-2-5 Erosion. (a) Qualifying condition. The site shall allow the...

  10. 10 CFR 960.5-2-5 - Environmental quality.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Environmental quality. 960.5-2-5 Section 960.5-2-5 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Preclosure Guidelines Environment, Socioeconomics, and Transportation § 960.5-2-5...

  11. 10 CFR 960.4-2-5 - Erosion.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Erosion. 960.4-2-5 Section 960.4-2-5 Energy DEPARTMENT OF... Postclosure Guidelines § 960.4-2-5 Erosion. (a) Qualifying condition. The site shall allow the underground... consider the climatic, tectonic, and geomorphic evidence of rates and patterns of erosion in the...

  12. 10 CFR 960.4-2-5 - Erosion.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Erosion. 960.4-2-5 Section 960.4-2-5 Energy DEPARTMENT OF... Postclosure Guidelines § 960.4-2-5 Erosion. (a) Qualifying condition. The site shall allow the underground... consider the climatic, tectonic, and geomorphic evidence of rates and patterns of erosion in the...

  13. 10 CFR 960.4-2-5 - Erosion.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Erosion. 960.4-2-5 Section 960.4-2-5 Energy DEPARTMENT OF... Postclosure Guidelines § 960.4-2-5 Erosion. (a) Qualifying condition. The site shall allow the underground... consider the climatic, tectonic, and geomorphic evidence of rates and patterns of erosion in the...

  14. 10 CFR 960.4-2-5 - Erosion.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Erosion. 960.4-2-5 Section 960.4-2-5 Energy DEPARTMENT OF... Postclosure Guidelines § 960.4-2-5 Erosion. (a) Qualifying condition. The site shall allow the underground... consider the climatic, tectonic, and geomorphic evidence of rates and patterns of erosion in the...

  15. 4 CFR 2.5 - Prohibited personnel practices.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 4 Accounts 1 2010-01-01 2010-01-01 false Prohibited personnel practices. 2.5 Section 2.5 Accounts GOVERNMENT ACCOUNTABILITY OFFICE PERSONNEL SYSTEM PURPOSE AND GENERAL PROVISION § 2.5 Prohibited personnel... concerning, the merit system principles described in § 2.4. (l) Information to the Congress. Nothing in...

  16. 2'-phosphodiesterase and 2',5'-oligoadenylate synthetase activities in the lowest metazoans, sponge [porifera].

    PubMed

    Saby, Emilie; Poulsen, Jesper Buchhave; Justesen, Just; Kelve, Merike; Uriz, Maria Jesus

    2009-01-01

    Sponges [porifera], the most ancient metazoans, contain modules related to the vertebrate immune system, including the 2',5'-oligoadenylate synthetase (OAS). The components of the antiviral 2',5'-oligoadenylate (2-5A) system (OAS, 2'-Phosphodiesterase (2'-PDE) and RNAse L) of vertebrates have not all been identified in sponges. Here, we demonstrate for the first time that in addition to the OAS activity, sponges possess a 2'-PDE activity, which highlights the probable existence of a premature 2-5A system. Indeed, Suberites domuncula and Crella elegans exhibited this 2-5A degrading activity. Upon this finding, two out of three elements forming the 2-5A system have been found in sponges, only a endoribonuclease, RNAse L or similar, has to be found. We suspect the existence of a complex immune system in sponges, besides the self/non-self recognition system and the use of phagocytosis and secondary metabolites against pathogens.

  17. The Campus in Hard Times. New York's Higher Education Crisis. How It Happened. How It Can Be Resolved.

    ERIC Educational Resources Information Center

    Paley, Henry D.

    How did the New York State system of colleges and universities arrive at the brink of fiscal disaster? What is a possible new perception of higher education financing for New York? The radical shift in enrollment from independent to government-sponsored campuses, and the steep escalation in tax-levy burden for higher education resulted in the New…

  18. CARDIOVASCULAR MORTALITY IN PHOENIX: PM1 IS A BETTER INDICATOR THAN PM2.5.

    EPA Science Inventory

    EPA has obtained a 3-year database of particulate matter (PM) in Phoenix, AZ from 1995 - 1997 that includes elemental analysis by XRF of daily PM2.5. During this time period PM1 and PM2.5 TEOMs were run simultaneously for about 7 months during two periods of the year. Regressio...

  19. Sulfur isotopic fractionation and source appointment of PM2.5 in Nanjing region around the second session of the Youth Olympic Games

    NASA Astrophysics Data System (ADS)

    Guo, Zhaobing; Shi, Lei; Chen, Shanli; Jiang, Wenjuan; Wei, Ying; Rui, Maoling; Zeng, Gang

    2016-06-01

    Sulfur isotopic compositions (δ34S) of PM2.5 in Nanjing region were determined in order to evaluate sulfur sources of PM2.5 around the second session of the Youth Olympic Games (YOG). Meanwhile, δ34S values from different potential sources of PM2.5, such as coal combustion, vehicle exhaust, and straw burning, were synchronously measured for the first time. The results showed that PM2.5 concentrations and δ34S values were much lower during the YOG (2 August to 11 September 2014) compared to those before (6 July to 1 August 2014) and after (15 September to 20 September 2014) the YOG. δ34S values of PM2.5 were generally located in a small range of 3.5‰ to 4.6‰, suggesting a stable sulfur sources in Nanjing region around the YOG. Combining with δ34S values of potential sources and SO2, ion concentrations of PM2.5 and MODIS fire spot photos, we inferred that sulfur in PM2.5 was mainly from direct emission of coal combustion and vehicle exhaust as well as the secondary sulfate from SO2 oxidation in the atmosphere. Besides, biologic sulfur release might make a contribution to sulfur content in PM2.5. High [NO3-]/[SO42 -] ratio of PM2.5 indicated that vehicle exhaust emission was predominant over coal combustion during the YOG. In addition, we studied sulfur isotopic fractionation coefficients during SO2 oxidation to sulfate in PM2.5 and found the contribution ratio (51.3%) of SO2 homogeneous oxidation was slightly higher than that (48.7%) of SO2 heterogeneous oxidation around the YOG.

  20. Comparison of composition of PM2.5 between haze and non-haze periods from 2012.3 to 2013.2 in Beijing

    NASA Astrophysics Data System (ADS)

    Fang, Y.; Zhu, T.; Wang, J.

    2014-12-01

    Fine particles (PM2.5) are complex compounds which are related to adverse health effects, visibility degradation and global climate change. A number of studies have focused on the components, sources and transportation of PM2.5all over the world. As the capital of China,suffering from the dense population and heavy traffic, Beijing has experienced serious air pollution, which can be easily proved by the increasing number of low-visibility days. In this study, we collected the daily PM2.5 samples from 2012.3 to 2013.2 to get the continuous data. The components of PM2.5 including ions, EC/OC and trace elements were obtained. Sulfate, nitrate, ammonium and organic matters (OM) are major components which account for more than 50% of PM2.5. Clearly seasonal variations are observed. Trace elements are highest in spring and lowest in summer. OM in winter is almost 3 times higher than that in summer. The percentage of OM has a significantly negative correlation with PM2.5 in summer and has no correlation with PM2.5 in winter at the p = 0.05 level, while indicates that in summer, the formation of organic compound may less important than in winter. The differences between seasons when haze episode occurred and the changes between haze and non-haze period will be discussed.

  1. Characteristics of concentrations and water-soluble inorganic ions in PM2.5 in Handan City, Hebei province, China

    NASA Astrophysics Data System (ADS)

    Meng, C. C.; Wang, L. T.; Zhang, F. F.; Wei, Z.; Ma, S. M.; Ma, X.; Yang, J.

    2016-05-01

    In order to explore the spatial, temporal, and chemical characteristics of fine particulate matter (PM2.5) pollution in Handan city, China, a comprehensive dataset including continuous online observations at four air quality monitoring stations in 2013 and 2014, and the concentrations of water-soluble inorganic ions (WSII) (NO3-, SO42 -, NH4+, Cl-, Na+, Mg2 +, K+, Ca2 +) in PM2.5 samples collected in four representative seasons in 2013 and 2014 are analyzed in this study. And the principal component analysis (PCA) method is applied to identify the source of WSII in Handan. Our results indicate that PM2.5 concentration decreased from 139.4 μg/m3 in 2013 to 116.0 μg/m3 in 2014 on annual average. Spatial variations of PM2.5 mass are not pronounced, indicating that PM2.5 is nearly evenly spread over the study area. The seasonal variations of PM2.5 concentration are significant, normally with 1.7 to 2.4 times higher in winter than in summer. The concentrations of TWSII (total water-soluble inorganic ions) remain relatively stable in two years, with annual averages of 63.1 μg/m3 in 2013 and 57.2 μg/m3 in 2014. SNA (SO42 -, NO3-, NH4+) dominates in the TWSII, accounting for ~ 87% of the TWSII. Similar to PM2.5, WSII exhibits obvious seasonal variations with higher concentrations in autumn and winter, lower in spring and summer. PM2.5 samples are acidic in spring, summer and autumn of 2013, while in winter of 2013 and all seasons of 2014, they are alkaline. SO42 -, NO3- are formed mainly through homogeneous reactions, heterogeneous reactions also exist in winter. Finally, the major sources of WSII in Handan are identified as the mixture of secondary origin, coal combustion, biomass burning (46.1%), dust sources (25.8%), and motor vehicle (12.3%).

  2. Cooking-related PM2.5 and acrolein measured in grocery stores and comparison with other retail types.

    PubMed

    Chan, W R; Sidheswaran, M; Sullivan, D P; Cohn, S; Fisk, W J

    2016-06-01

    We measured particulate matter (PM), acrolein, and other indoor air contaminants in eight visits to grocery stores in California. Retail stores of other types (hardware, furniture, and apparel) were also sampled on additional visits. Based on tracer gas decay data, most stores had adequate ventilation according to minimum ventilation rate standards. Grocery stores had significantly higher concentrations of acrolein, fine and ultrafine PM, compared to other retail stores, likely attributable to cooking. Indoor concentrations of PM2.5 and acrolein exceeded health guidelines in all tested grocery stores. Acrolein emission rates to indoors in grocery stores had a mean estimate about 30 times higher than in other retail store types. About 80% of the indoor PM2.5 measured in grocery stores was emitted indoors, compared to only 20% for the other retail store types. Calculations suggest a substantial increase in outdoor air ventilation rate by a factor of three from current level is needed to reduce indoor acrolein concentrations. Alternatively, acrolein emission to indoors needs to be reduced 70% by better capturing of cooking exhaust. To maintain indoor PM2.5 below the California annual ambient standard of 12 μg/m(3) , grocery stores need to use air filters with an efficiency rating higher than the MERV 8 air filters commonly used today.

  3. Sources, transformation, and health implications of PAHs and their nitrated, hydroxylated, and oxygenated derivatives in PM2.5 in Beijing

    NASA Astrophysics Data System (ADS)

    Lin, Yan; Ma, Yiqiu; Qiu, Xinghua; Li, Ran; Fang, Yanhua; Wang, Junxia; Zhu, Yifang; Hu, Di

    2015-07-01

    Fine particulate matter (PM2.5) is a significant health issue in Chinese megacities. However, little information is available regarding the PM2.5-bound toxic organics, especially their sources, atmospheric transformations, and health implications. In this study, we assessed the levels of polycyclic aromatic hydrocarbons (PAHs) and their nitrated, hydroxylated, and oxygenated derivatives (i.e., NPAHs, OHPAHs, and OPAHs, respectively) in PM2.5 collected in Beijing over a 1 year period. The median concentration of 23 PAHs, 15 NPAHs, 16 OHPAHs, and 7 OPAHs in PM2.5 was 53.8, 1.14, 1.40, and 3.62 ng m-3, respectively. Much higher concentrations and mass percentages for all species were observed in the heating season, indicating a higher toxicity of PM2.5 during this period of time. Positive matrix factorization was applied to apportion the sources of PAHs and their derivatives. It was found that traffic emissions in the nonheating season, and coal combustion and biomass burning in the heating season, were the major primary sources of PAHs and their derivatives. Secondary formation, however, contributed significantly to the derivatives of PAHs (especially NPAHs and OPAHs) in the nonheating season, suggesting significant impacts of atmospheric transformation on the toxicity of PM2.5.

  4. Exposure to PM2.5 and Blood Lead Level in Two Populations in Ulaanbaatar, Mongolia

    PubMed Central

    Enkhbat, Undarmaa; Rule, Ana M.; Resnick, Carol; Ochir, Chimedsuren; Olkhanud, Purevdorj; Williams, D’Ann L.

    2016-01-01

    Approximately 60% of the households in Ulaanbaatar live in gers (a traditional Mongolian dwelling) in districts outside the legal limits of the city, without access to basic infrastructure, such as water, sewage systems, central heating, and paved roads, in contrast to apartment residents. This stark difference in living conditions creates different public health challenges for Ulaanbaatar residents. Through this research study we aim to test our hypothesis that women living in gers burning coal in traditional stoves for cooking and heating during the winter are exposed to higher concentrations of airborne PM2.5 than women living in apartments in Ulaanbaatar, Mongolia, and this exposure may include exposures to lead in coal with effects on blood lead levels. This cross-sectional study recruited a total of 50 women, 40–60 years of age, from these two settings. Air sampling was carried out during peak cooking and heating times, 5:00 p.m.–11:00 p.m., using a direct-reading instrument (TSI SidePak™) and integrated polytetrafluoroethylene (PTFE) filters using the SKC Personal Environmental Monitor. Blood lead level (BLL) was measured using a LeadCare II rapid field test method. In our study population, measured PM2.5 geometric mean (GM) concentrations using the SidePak™ in the apartment group was 31.5 (95% CI:17–99) μg/m3, and 100 (95% CI: 67–187) μg/m3 in ger households (p < 0.001). The GM integrated gravimetric PM2.5 concentrations in the apartment group were 52.8 (95% CI: 39–297) μg/m3 and 127.8 (95% CI: 86–190) μg/m3 in ger households (p = 0.004). The correlation coefficient for the SidePak™ PM2.5 concentrations and filter based PM2.5 concentrations was r = 0.72 (p < 0.001). Blood Lead Levels were not statistically significant different between apartment residents and ger residents (p = 0.15). The BLL is statistically significant different (p = 0.01) when stratified by length of exposures outside of the home. This statistically significant

  5. Exposure to PM2.5 and Blood Lead Level in Two Populations in Ulaanbaatar, Mongolia.

    PubMed

    Enkhbat, Undarmaa; Rule, Ana M; Resnick, Carol; Ochir, Chimedsuren; Olkhanud, Purevdorj; Williams, D'Ann L

    2016-02-15

    Approximately 60% of the households in Ulaanbaatar live in gers (a traditional Mongolian dwelling) in districts outside the legal limits of the city, without access to basic infrastructure, such as water, sewage systems, central heating, and paved roads, in contrast to apartment residents. This stark difference in living conditions creates different public health challenges for Ulaanbaatar residents. Through this research study we aim to test our hypothesis that women living in gers burning coal in traditional stoves for cooking and heating during the winter are exposed to higher concentrations of airborne PM2.5 than women living in apartments in Ulaanbaatar, Mongolia, and this exposure may include exposures to lead in coal with effects on blood lead levels. This cross-sectional study recruited a total of 50 women, 40-60 years of age, from these two settings. Air sampling was carried out during peak cooking and heating times, 5:00 p.m.-11:00 p.m., using a direct-reading instrument (TSI SidePak™) and integrated polytetrafluoroethylene (PTFE) filters using the SKC Personal Environmental Monitor. Blood lead level (BLL) was measured using a LeadCare II rapid field test method. In our study population, measured PM2.5 geometric mean (GM) concentrations using the SidePak™ in the apartment group was 31.5 (95% CI:17-99) μg/m³, and 100 (95% CI: 67-187) μg/m³ in ger households (p < 0.001). The GM integrated gravimetric PM2.5 concentrations in the apartment group were 52.8 (95% CI: 39-297) μg/m³ and 127.8 (95% CI: 86-190) μg/m³ in ger households (p = 0.004). The correlation coefficient for the SidePak™ PM2.5 concentrations and filter based PM2.5 concentrations was r = 0.72 (p < 0.001). Blood Lead Levels were not statistically significant different between apartment residents and ger residents (p = 0.15). The BLL is statistically significant different (p = 0.01) when stratified by length of exposures outside of the home. This statistically significant difference

  6. Exposure to PM2.5 and Blood Lead Level in Two Populations in Ulaanbaatar, Mongolia.

    PubMed

    Enkhbat, Undarmaa; Rule, Ana M; Resnick, Carol; Ochir, Chimedsuren; Olkhanud, Purevdorj; Williams, D'Ann L

    2016-02-01

    Approximately 60% of the households in Ulaanbaatar live in gers (a traditional Mongolian dwelling) in districts outside the legal limits of the city, without access to basic infrastructure, such as water, sewage systems, central heating, and paved roads, in contrast to apartment residents. This stark difference in living conditions creates different public health challenges for Ulaanbaatar residents. Through this research study we aim to test our hypothesis that women living in gers burning coal in traditional stoves for cooking and heating during the winter are exposed to higher concentrations of airborne PM2.5 than women living in apartments in Ulaanbaatar, Mongolia, and this exposure may include exposures to lead in coal with effects on blood lead levels. This cross-sectional study recruited a total of 50 women, 40-60 years of age, from these two settings. Air sampling was carried out during peak cooking and heating times, 5:00 p.m.-11:00 p.m., using a direct-reading instrument (TSI SidePak™) and integrated polytetrafluoroethylene (PTFE) filters using the SKC Personal Environmental Monitor. Blood lead level (BLL) was measured using a LeadCare II rapid field test method. In our study population, measured PM2.5 geometric mean (GM) concentrations using the SidePak™ in the apartment group was 31.5 (95% CI:17-99) μg/m³, and 100 (95% CI: 67-187) μg/m³ in ger households (p < 0.001). The GM integrated gravimetric PM2.5 concentrations in the apartment group were 52.8 (95% CI: 39-297) μg/m³ and 127.8 (95% CI: 86-190) μg/m³ in ger households (p = 0.004). The correlation coefficient for the SidePak™ PM2.5 concentrations and filter based PM2.5 concentrations was r = 0.72 (p < 0.001). Blood Lead Levels were not statistically significant different between apartment residents and ger residents (p = 0.15). The BLL is statistically significant different (p = 0.01) when stratified by length of exposures outside of the home. This statistically significant difference

  7. Fine particles (PM2.5) in ambient air of Lucknow city due to fireworks on Diwali festival.

    PubMed

    Barman, S C; Singh, Ramesh; Negi, M P S; Bhargava, S K

    2009-09-01

    People burn crackers world over on different occasions in different countries to express their happiness. Fireworks in large amounts aggravate the level of air pollutants and cause significant short-term air quality degradation with possible impact on human health. Fine particles (PM2.5 < or = 2.5 microm), which may pose detrimental effects on human health and ecosystems were monitored in a residential area of Lucknow city to assess the elevated level due to bursting of firecrackers during Diwali festival. The 24 hr mean PM2.5 of normal day, pre Diwali day, Diwali day and post Diwali day was found to be 124, 154, 352 and 174 microg m(-3) respectively and much above the US-EPA limit (65 microg m(-3)). The 12 hr mean concentration of PM2.5 on Diwali night (591 microg m(-3)) increased 3.9 fold than the respective night of normal day (159 microg m(-3)) and was significantly higher (p<0.01) than normal day and pre and post Diwali night. Mean comparison showed that Diwali day was significantly (p<0.01) different from others (except post Diwali day) and for this high accumulation during night time, after fireworks (suspension) was found to be more responsible than the period of lighting of crackers (formation). This study indicated that there is high accumulation of PM2.5 generated due to fireworks on Diwali festival which remains suspended in the air for up to 20 hr During this period, extra mass burden of 289 microg m(-3) equivalent to 1.9 normal day (of this study) was imposed in the environment. The short-term high accumulation of PM2.5 is a matter of serious concern for city dwellers as it can penetrate deep into the lungs and cause many respiratory and cardiovascular diseases.

  8. Estimating adult mortality attributable to PM2.5 exposure in China with assimilated PM2.5 concentrations based on a ground monitoring network.

    PubMed

    Liu, Jun; Han, Yiqun; Tang, Xiao; Zhu, Jiang; Zhu, Tong

    2016-10-15

    Estimates of mortality attributable to air pollution in China showed large differences among various studies, mainly arising from differences in exposure assessments and choice of the concentration-response function. The Chinese national monitoring network recently has included direct measurements of PM2.5 (particulates with aerodynamic diameter≤2.5μm), providing a potentially more reliable exposure assessment. We estimated adult premature mortalities due to PM2.5 across China in 2013 and mortality benefits for scenarios in which China meets the World Health Organization (WHO) Air Quality Guidelines (AQG) and three interim targets (ITs) for PM2.5. Attributable adult mortalities were estimated with assimilated spatial PM2.5 concentrations across China based on direct PM2.5 measurements from 506 PM2.5 monitoring sites and a regional air quality model, and using the integrated exposure-response model. Our results show that in China, 83% of the population lived in areas where PM2.5 concentrations exceeded the Chinese Ambient Air Quality Standard of 35μgm(-3). Premature mortalities attributed to PM2.5 nationwide were 1.37 million in total, and 0.69, 0.38, 0.13, and 0.17 million for stroke, ischemic heart disease, lung cancer, and chronic obstructive pulmonary disease, respectively. High population density areas exhibited the highest health risks attributed to air pollution. The mortality benefits will be 23%, 39%, 66%, and 83% of the total present premature mortalities (1.37 million mortalities) when PM2.5 concentrations in China meet the WHO IT-1, IT-2, IT-3, and AQG, respectively. Our study shows that integrating PM2.5 concentrations based on the national monitoring network with the regional air quality model provides an advanced exposure estimate method with potentials to further improve the accuracy for mortality estimate; much higher health benefits could be achieved if China adopted more stringent WHO guidelines for PM2.5. PMID:27266521

  9. Selective cytotoxicity of PAMAM G5 core–PAMAM G2.5 shell tecto-dendrimers on melanoma cells

    PubMed Central

    Schilrreff, Priscila; Mundiña-Weilenmann, Cecilia; Romero, Eder Lilia; Morilla, Maria Jose

    2012-01-01

    Background The controlled introduction of covalent linkages between dendrimer building blocks leads to polymers of higher architectural order known as tecto-dendrimers. Because of the few simple steps involved in their synthesis, tecto-dendrimers could expand the portfolio of structures beyond commercial dendrimers, due to the absence of synthetic drawbacks (large number of reaction steps, excessive monomer loading, and lengthy chromatographic separations) and structural constraints of high-generation dendrimers (reduction of good monodispersity and ideal dendritic construction due to de Gennes dense-packing phenomenon). However, the biomedical uses of tecto-dendrimers remain unexplored. In this work, after synthesizing saturated shell core–shell tecto-dendrimers using amine-terminated polyamidoamine (PAMAM) generation 5 (G5) as core and carboxyl-terminated PAMAM G2.5 as shell (G5G2.5 tecto-dendrimers), we surveyed for the first time the main features of their interaction with epithelial cells. Methods Structural characterization of G5G2.5 was performed by polyacrylamide gel electrophoresis, matrix-assisted laser desorption time-of-flight mass spectrometry, and microscopic techniques; their hydrodynamic size and Z-potential was also determined. Cellular uptake by human epidermal keratinocytes, colon adenocarcinoma, and epidermal melanoma (SK-Mel-28) cells was determined by flow cytometry. Cytotoxicity was determined by mitochondrial activity, lactate dehydrogenase release, glutathione depletion, and apoptosis/necrosis measurement. Results The resultant 60%–67% saturated shell, 87,000-dalton G5G2.5 (mean molecular weight) interacted with cells in a significantly different fashion in comparison to their building blocks and to its closest counterpart, PAMAM G6.5. After being actively taken up by epithelial cells, G5G2.5 caused cytotoxicity only on SK-Mel-28 cells, including depletion of intracellular glutathione and fast necrosis that was manifested above 5 μM G5

  10. Educational Family Background and the Realisation of Educational Career Intentions: Participation of German Upper Secondary Graduates in Higher Education over Time

    ERIC Educational Resources Information Center

    Weiss, Felix; Steininger, Hanna-Marei

    2013-01-01

    In this article, we evaluate the impact of social origin on the realisation of educational intentions at the time of becoming eligible for higher education in Germany. In general, we find high persistence of intentions and actual attendance of higher education. However, effects of parental education on the changes of educational intentions…

  11. Indicators reflecting local and transboundary sources of PM2.5 and PMCOARSE in Rome - Impacts in air quality

    NASA Astrophysics Data System (ADS)

    Dimitriou, Konstantinos; Kassomenos, Pavlos

    2014-10-01

    The keystone of this paper was to calculate and interpret indicators reflecting sources and air quality impacts of PM2.5 and PMCOARSE (PM10-PM2.5) in Rome (Italy), focusing on potential exogenous influences. A backward atmospheric trajectory cluster analysis was implemented. The likelihood of daily PM10 exceedances was studied in conjunction with atmospheric patterns, whereas a Potential Source Contribution Function (PSCF) based on air mass residence time was deployed on a grid of a 0.5° × 0.5° resolution. Higher PM2.5 concentrations were associated with short/medium range airflows originated from Balkan Peninsula, whereas potential PMCOARSE sources were localized across the Mediterranean and coastal North Africa, due to dust and sea spray transportation. According to the outcome of a daily Pollution Index (PI), a slightly increased degradation of air quality is induced due to the additional quantity of exogenous PM but nevertheless, average levels of PI in all trajectory clusters belong in the low pollution category. Gaseous and particulate pollutants were also elaborated by a Principal Component Analysis (PCA), which produced 4 components: [Traffic], [photochemical], [residential] and [Secondary Coarse Aerosol], reflecting local sources of air pollution. PM2.5 levels were strongly associated with traffic, whereas PMCOARSE were produced autonomously by secondary sources.

  12. Effects of Meteorological Conditions on PM2.5 Concentrations in Nagasaki, Japan.

    PubMed

    Wang, Jianhua; Ogawa, Susumu

    2015-08-01

    The fine particulate matter (PM2.5) problem has attracted much scientific and public attention, due to its effects on visibility, human health, and global climate. There are three factors that have important effect on PM2.5 mass concentration: domestic pollutant emission sources, external sources outside of the country, and the meteorological conditions. Nagasaki is a coastal prefecture located at the westernmost part of Japan, which is an ideal location to study pollutants from long range transport and correlation between PM2.5 and meteorological conditions. In this paper, PM2.5 concentration data and meteorological data were obtained during 1 January 2013~31 December 2013. The spatial distribution depicts that the western part of the study area has the most serious PM2.5 pollution. The correlation analysis results between PM2.5 concentration and meteorological data showed that temperature had a negative, and precipitation had a positive, correlation with PM2.5. There was a threshold in the correlations between humidity and wind speed and PM2.5. The correlation was positive or negative depending on the meteorological variable values, if these were lower or higher than the threshold. From the relationship with wind direction, it can be depicted that the west wind might bring the most pollutants to Nagasaki. PMID:26247953

  13. Effects of Meteorological Conditions on PM2.5 Concentrations in Nagasaki, Japan

    PubMed Central

    Wang, Jianhua; Ogawa, Susumu

    2015-01-01

    The fine particulate matter (PM2.5) problem has attracted much scientific and public attention, due to its effects on visibility, human health, and global climate. There are three factors that have important effect on PM2.5 mass concentration: domestic pollutant emission sources, external sources outside of the country, and the meteorological conditions. Nagasaki is a coastal prefecture located at the westernmost part of Japan, which is an ideal location to study pollutants from long range transport and correlation between PM2.5 and meteorological conditions. In this paper, PM2.5 concentration data and meteorological data were obtained during 1 January 2013~31 December 2013. The spatial distribution depicts that the western part of the study area has the most serious PM2.5 pollution. The correlation analysis results between PM2.5 concentration and meteorological data showed that temperature had a negative, and precipitation had a positive, correlation with PM2.5. There was a threshold in the correlations between humidity and wind speed and PM2.5. The correlation was positive or negative depending on the meteorological variable values, if these were lower or higher than the threshold. From the relationship with wind direction, it can be depicted that the west wind might bring the most pollutants to Nagasaki. PMID:26247953

  14. Source of Personal Exposure to PM2.5 among College Students in Beijing, China

    NASA Astrophysics Data System (ADS)

    Xie, Qiaorong; Zhu, Xianlei; Li, Xiang; Hui, Fan; Fu, Xianqiang; Zhang, Qiangbin

    2015-04-01

    The health risk from exposure to airborne particles arouses increasing public concern in Beijing, a megacity in China, where concentration of PM2.5 frequently exceeds the guideline values of World Health Organization (WHO). To investigate daily exposure to PM2.5, a personal exposure study was conducted for college students. The purpose of this study was to measure the daily PM2.5 personal exposures of students, to quantify the contributions of various microenvironments to personal exposure since students spend more than 85% of their time indoors, and to apportion the contributions of PM2.5 indoors origin and outdoor origin. In this work, a total of 320 paired indoor and outdoor PM2.5 samples were collected at eight types of microenvironments in both China University of Petroleum (suburban area) and Tsinghua University (urban area). The microenvironments were selected based on the time-activity diary finished by 1500 students from both universities. Simultaneously, the air exchange rate was measured in each microenvironment. PM2.5, elements, inorganic ions and polycyclic aromatic hydrocarbons in the samples were determined. The peak concentrations were observed in dinning halls, whereas PM2.5 in dormitories was the largest contributor to personal exposure because students spend more than half of a day there. Furthermore, source apportionment by positive matrix factorization (PMF) will be carried out to understand the source of personal exposure to PM2.5. Especially, efforts will be put on determing the contributions of primary combustion, secondary sulfate and organics, secondary nitrate, and mechanically generated PM, which present different infiltration behavior and are indoor PM2.5 of ambient origin, with help of air exchange rate data. The results would be benefit for refining the understanding of the contribution of PM2.5 of ambient (outdoor) origin to the daily PM2.5 personal exposures. Acknowledgments:This study has been funded by Beijing Municipal Commission

  15. Transported vs. local contributions from secondary and biomass burning sources to PM2.5

    NASA Astrophysics Data System (ADS)

    Kim, Bong Mann; Seo, Jihoon; Kim, Jin Young; Lee, Ji Yi; Kim, Yumi

    2016-11-01

    The concentration of fine particulates in Seoul, Korea has been lowered over the past 10 years, as a result of the city's efforts in implementing environmental control measures. Yet, the particulate concentration level in Seoul remains high as compared to other urban areas globally. In order to further improve fine particulate air quality in the Korea region and design a more effective control strategy, enhanced understanding of the sources and contribution of fine particulates along with their chemical compositions is necessary. In turn, relative contributions from local and transported sources on Seoul need to be established, as this city is particularly influenced by sources from upwind geographic areas. In this study, PM2.5 monitoring was conducted in Seoul from October 2012 to September 2013. PM2.5 mass concentrations, ions, metals, organic carbon (OC), elemental carbon (EC), water soluble OC (WSOC), humic-like substances of carbon (HULIS-C), and 85 organic compounds were chemically analyzed. The multivariate receptor model SMP was applied to the PM2.5 data, which then identified nine sources and estimated their source compositions as well as source contributions. Prior studies have identified and quantified the transported and local sources. However, no prior studies have distinguished contributions of an individual source between transported contribution and locally produced contribution. We differentiated transported secondary and biomass burning sources from the locally produced secondary and biomass burning sources, which was supported with potential source contribution function (PSCF) analysis. Of the total secondary source contribution, 32% was attributed to transported secondary sources, and 68% was attributed to locally formed secondary sources. Meanwhile, the contribution from the transported biomass burning source was revealed as 59% of the total biomass burning contribution, which was 1.5 times higher than that of the local biomass burning source

  16. Chemical characterization and mass closure of PM10 and PM2.5 at an urban site in Karachi - Pakistan

    NASA Astrophysics Data System (ADS)

    Shahid, Imran; Kistler, Magdalena; Mukhtar, Azam; Ghauri, Badar M.; Ramirez-Santa Cruz, Carlos; Bauer, Heidi; Puxbaum, Hans

    2016-03-01

    A mass balance method is applied to assess main source contributions to PM2.5 and PM10 levels in Karachi. Carbonaceous species (elemental carbon, organic carbon, carbonate carbon), soluble ions (Ca++, Mg++, Na+, K+, NH4+, Cl-, NO3-, SO4-), saccharides (levoglucosan, galactosan, mannosan, sucrose, fructose, glucose, arabitol and mannitol) were determined in atmospheric fine (PM2.5) and coarse (PM10) aerosol samples collected under pre-monsoon conditions (March-April 2009) at an urban site in Karachi (Pakistan). The concentrations of PM2.5 and PM10 were found to be 75 μg/m3 and 437 μg/m3 respectively. The large difference between PM10 and PM2.5 originated predominantly from mineral dust. "Calcareous dust" and "siliceous dust" were the over all dominating material in PM, with 46% contribution to PM2.5 and 78% to PM10-2.5. Combustion particles and secondary organics (EC + OM) comprised 23% of PM2.5 and 6% of PM10-2.5. EC, as well as OC ambient levels were higher (59% and 56%) in PM10-2.5 than in PM2.5. Biomass burning contributed about 3% to PM2.5, and had a share of about 13% of "EC + OM" in PM2.5. The impact of bioaerosol (fungal spores) was minor and had a share of 1 and 2% of the OC in the PM2.5 and PM10-2.5 size fractions. In case of secondary inorganic aerosols, ammonium sulphate (NH4)2SO4 contributes 4.4% to PM2.5 and no detectable quantity were found in fraction PM10-2.5. The sea salt contribution is about 2% both to PM2.5 and PM10-2.5.

  17. Chemical characterization and mass closure of PM10 and PM2.5 at an urban site in Karachi - Pakistan

    NASA Astrophysics Data System (ADS)

    Shahid, Imran; Kistler, Magdalena; Mukhtar, Azam; Ghauri, Badar M.; Ramirez-Santa Cruz, Carlos; Bauer, Heidi; Puxbaum, Hans

    2016-03-01

    A mass balance method is applied to assess main source contributions to PM2.5 and PM10 levels in Karachi. Carbonaceous species (elemental carbon, organic carbon, carbonate carbon), soluble ions (Ca++, Mg++, Na+, K+, NH4+, Cl‑, NO3‑, SO4‑), saccharides (levoglucosan, galactosan, mannosan, sucrose, fructose, glucose, arabitol and mannitol) were determined in atmospheric fine (PM2.5) and coarse (PM10) aerosol samples collected under pre-monsoon conditions (March-April 2009) at an urban site in Karachi (Pakistan). The concentrations of PM2.5 and PM10 were found to be 75 μg/m3 and 437 μg/m3 respectively. The large difference between PM10 and PM2.5 originated predominantly from mineral dust. "Calcareous dust" and "siliceous dust" were the over all dominating material in PM, with 46% contribution to PM2.5 and 78% to PM10-2.5. Combustion particles and secondary organics (EC + OM) comprised 23% of PM2.5 and 6% of PM10-2.5. EC, as well as OC ambient levels were higher (59% and 56%) in PM10-2.5 than in PM2.5. Biomass burning contributed about 3% to PM2.5, and had a share of about 13% of "EC + OM" in PM2.5. The impact of bioaerosol (fungal spores) was minor and had a share of 1 and 2% of the OC in the PM2.5 and PM10-2.5 size fractions. In case of secondary inorganic aerosols, ammonium sulphate (NH4)2SO4 contributes 4.4% to PM2.5 and no detectable quantity were found in fraction PM10-2.5. The sea salt contribution is about 2% both to PM2.5 and PM10-2.5.

  18. A Call to Action on New England's Innovation Economy: Will Business and Higher Education Answer This Time?

    ERIC Educational Resources Information Center

    Guenther, William

    2003-01-01

    Mass Insight Corp, a public policy and communications firm that organizes public-private initiatives to support economic growth in Massachusetts, recently issued a new report, titled "An Economy at Risk," making the case for a Massachusetts economic development strategy organized around higher education and science and technology. Massachusetts,…

  19. Universities' Autonomy in Times of Changing Higher Education Governance: A Study of the Swiss Academic Labour Market

    ERIC Educational Resources Information Center

    Baschung, Lukas; Goastellec, Gaele; Leresche, Jean-Philippe

    2011-01-01

    Although eternally debated, the issue of autonomy in higher education is rarely analysed in its complexity. To address this issue, this article uses an analytical matrix which combines the distinction between substantive and procedural autonomy and the distinction between HEI governing bodies, academic professions and individual academics. This…

  20. Breaking the Mold: New Approaches for Higher Education in Tough Economic Times. Complete to Compete Briefing Paper

    ERIC Educational Resources Information Center

    Carey, Kevin

    2011-01-01

    Human capital is the key to economic development. Without highly-skilled workers, states and territories cannot attract the productive businesses they need. That makes higher education a key element of any governor's growth strategy. But many public colleges and universities are struggling to produce more graduates. Overall graduation rates often…

  1. Quality after the Cuts? Higher Education Practitioners' Accounts of Systemic Challenges to Teaching Quality in Times of "Austerity"

    ERIC Educational Resources Information Center

    Feigenbaum, Anna; Iqani, Mehita

    2015-01-01

    What are the ramifications of current changes in the higher education landscape in the UK for the ways in which teaching staff perceive their teaching practices? What impact are funding cuts, increases in student fees and the concomitant increased workloads having on faculty morale? How might this influence "quality cultures" in teaching…

  2. Australian Higher Education Leaders in Times of Change: The Role of Pro Vice-Chancellor and Deputy Vice-Chancellor

    ERIC Educational Resources Information Center

    Scott, Geoff; Bell, Sharon; Coates, Hamish; Grebennikov, Leonid

    2010-01-01

    This paper discusses responses provided by 31 Pro Vice-Chancellors (PVCs) and Deputy Vice-Chancellors (DVCs) who were part of a larger study of more than 500 higher education leaders in roles ranging from DVC to head of programme in 20 Australian universities. Using both quantitative and qualitative data the paper gives an insider's perspective on…

  3. A Lesson of Lost Political Capital in Public Higher Education: Leadership Challenges in a Time of Needed Organizational Change

    ERIC Educational Resources Information Center

    Hilton, Mark; Jacobson, Rod

    2012-01-01

    All higher education institutions are struggling with a rapidly changing market and financial landscape. Here is a management-centered analysis of what happened when a college president, recognizing the need to make a radical adaptation to those changes, tried moving a campus community to a new organizational model, without collegial consensus,…

  4. Applying the Modality Principle to Real-Time Feedback and the Acquisition of Higher-Order Cognitive Skills

    ERIC Educational Resources Information Center

    Fiorella, Logan; Vogel-Walcutt, Jennifer J.; Schatz, Sae

    2012-01-01

    Effectively presenting complex material is a crucial component of instructional design within simulation-based training (SBT) environments. One approach to facilitate the acquisition of higher-order knowledge is to embed instructional strategies within the systems themselves. Currently, however, there are few established guidelines to inform…

  5. A Time of Quiet Activism: Research, Practice, and Policy in American Women's Higher Education, 1945-1965

    ERIC Educational Resources Information Center

    Eisenmann, Linda

    2005-01-01

    This article reflects on three narratives that affected American women's participation in higher education during the first twenty years after World War II. In hindsight, the educators of the 1950s and early 1960s may seem gratuitously meek and self-effacing. In comparison to later efforts, their activism can appear unnecessarily limited and too…

  6. Unprecedented Times in the Professionalisation and State Regulation of Counselling and Psychotherapy: The Role of the Higher Education Institute

    ERIC Educational Resources Information Center

    Murphy, David

    2011-01-01

    This article considers a number of issues facing those involved in counselling and psychotherapy training within United Kingdom Higher Education Institutes. It is proposed that the increasing professionalisation of counselling and psychotherapy has significant implications for lecturers and trainers. The article will explore the tension between…

  7. Just-in-Time Research: A Call to Arms for Research into Mobile Technologies in Higher Education

    ERIC Educational Resources Information Center

    Byrne-Davis, Lucie; Dexter, Hilary; Hart, Jo; Cappelli, Tim; Byrne, Ged; Sampson, Ian; Mooney, Jane; Lumsden, Colin

    2015-01-01

    Mobile technologies are becoming commonplace in society and in education. In higher education, it is crucial to understand the impact of constant access to information on the development of the knowledge and competence of the learner. This study reports on a series of four surveys completed by UK-based medical students (n = 443) who received…

  8. Funding System of Full-Time Higher Education and Technical Efficiency: Case of the University of Ljubljana

    ERIC Educational Resources Information Center

    Tajnikar, Maks; Debevec, Jasmina

    2008-01-01

    The present paper tackles the issue of the higher education funding system in Slovenia. Its main attribute is that institutions are classified into study groups according to their fields of education, and funds granted by the state are based on their weights or study group factors (SGF). Analysis conducted using data envelopment analysis tested…

  9. [Variation characteristics of fine particulate matter PM2.5 concentration in three urban recreational forests in Hui Mountain of Wuxi City, Jiangsu Province of East China].

    PubMed

    Gu, Lin; Wang, Cheng; Wang, Xiao-Lei; Wang, Yan-Ying; Wang, Qian

    2013-09-01

    It is of significance to understand the controlling effects of urban forest on atmospheric fine particulate matter PM2.5 pollution. This paper monitored the variations of atmospheric PM2.5 concentrations in three typical urban recreational forests (Cinnamomum camphora, Pinus elliotii, and Quercus variabilis ) in the Hui Mountain of Wuxi City during the day time (5:00 am-19:00 pm) in autumn and winter, 2011 and in spring and summer, 2012. The meteorological factors were observed simultaneously. The average annual PM2.5 concentration in the three recreational forests was lower than that above the nearby roads, and this concentration in C. camphora and P. elliotii forests was lower than that in Q. variabilis forest. The average annual PM2.5 concentration in the forests and above the nearby roads was lower than the background value in the downtown area of the City. The PM2.5 concentration in the three recreational forests was the lowest in summer, followed by in autumn, and the highest in spring. In addition, the PM2.5 concentration was the lowest in P. elliotii forest in spring, summer, and winter, and in C. camphora forest in autumn, but relatively higher in Q. variabilis forest in all seasons. The diurnal variation of the PM2.5 concentration in the three forests in four seasons all showed nearly "one peak and one vale", with the peak and vale appeared at 7:00-9:00 and 15:00-19:00, respectively. The PM2.5 concentration was significantly correlated with the air moisture and temperature in four seasons, and significantly correlated with the light intensity in winter. Mild winds throughout the seasons had little effects on the PM2.5 concentration.

  10. Influence of quarry mining dust on PM2.5 in a city adjacent to a limestone quarry: Seasonal characteristics and source contributions.

    PubMed

    Peng, Xing; Shi, Guo-Liang; Zheng, Jun; Liu, Jia-Yuan; Shi, Xu-Rong; Xu, Jiao; Feng, Yin-Chang

    2016-04-15

    To understand the influence of quarry mining dust on particulate matter, ambient PM2.5 and quarry mining dust source samples were collected in a city near quarry facilities during 2013-2014. Samples were subject to chemical analysis for dust-related species (Al, Si, Ca, Fe, Ti), tracer metals, carbon components and water-soluble ions. Seasonal variations of PM2.5 and its main chemical components were investigated. Distinctive seasonal variations of PM2.5 were observed, with the highest PM2.5 concentrations (112.42μgm(-3)) in fall and lowest concentrations in summer (45.64μgm(-3)). For dust-related species, mass fractions of Si and Al did not show obvious seasonal variations, whereas Ca presented higher fractions in spring and summer and lower fractions in fall and winter. A combined receptor model (PMF-CMB) was applied to quantify the quarry mining dust contribution to PM2.5. Seven sources were identified, including quarry mining dust, soil dust, cement dust, coal combustion vehicles, secondary sulfate and secondary nitrate. On a yearly average basis, the contribution of quarry mining dust to PM2.5 was 6%. The contribution of soil dust to PM2.5 was comparable with cement dust (13% and 13%, respectively). Other identified sources included vehicle, secondary sulfate, secondary nitrate and coal combustion, which contributed 23, 15, 9 and 18% of the total mass, respectively. Air mass residence time (AMRT) analysis showed that northeast and southeast regions might be the major PM2.5 source during the sampling campaign. The findings of this study can be used to understand the characteristics of quarry mining dust and control strategies for PM2.5.

  11. [Variation characteristics of fine particulate matter PM2.5 concentration in three urban recreational forests in Hui Mountain of Wuxi City, Jiangsu Province of East China].

    PubMed

    Gu, Lin; Wang, Cheng; Wang, Xiao-Lei; Wang, Yan-Ying; Wang, Qian

    2013-09-01

    It is of significance to understand the controlling effects of urban forest on atmospheric fine particulate matter PM2.5 pollution. This paper monitored the variations of atmospheric PM2.5 concentrations in three typical urban recreational forests (Cinnamomum camphora, Pinus elliotii, and Quercus variabilis ) in the Hui Mountain of Wuxi City during the day time (5:00 am-19:00 pm) in autumn and winter, 2011 and in spring and summer, 2012. The meteorological factors were observed simultaneously. The average annual PM2.5 concentration in the three recreational forests was lower than that above the nearby roads, and this concentration in C. camphora and P. elliotii forests was lower than that in Q. variabilis forest. The average annual PM2.5 concentration in the forests and above the nearby roads was lower than the background value in the downtown area of the City. The PM2.5 concentration in the three recreational forests was the lowest in summer, followed by in autumn, and the highest in spring. In addition, the PM2.5 concentration was the lowest in P. elliotii forest in spring, summer, and winter, and in C. camphora forest in autumn, but relatively higher in Q. variabilis forest in all seasons. The diurnal variation of the PM2.5 concentration in the three forests in four seasons all showed nearly "one peak and one vale", with the peak and vale appeared at 7:00-9:00 and 15:00-19:00, respectively. The PM2.5 concentration was significantly correlated with the air moisture and temperature in four seasons, and significantly correlated with the light intensity in winter. Mild winds throughout the seasons had little effects on the PM2.5 concentration. PMID:24417105

  12. Full-Time Employed Students as University Consumers--Consequences and Triggers of Marketisation of Higher Education

    ERIC Educational Resources Information Center

    Mägi, Eve; Jaakson, Krista; Aidla, Anne; Kirss, Laura; Reino, Anne

    2012-01-01

    This article draws on a qualitative study of student employment patterns among students who both study and work full-time. In the study, 17 employed bachelor students at state-commissioned study places in three Estonian universities, 12 lecturers from the same universities, and 13 employers supervising those full-time students, were interviewed.…

  13. Intake fraction of PM2.5 and NOX from vehicle emissions in Beijing based on personal exposure data

    NASA Astrophysics Data System (ADS)

    Du, Xuan; Wu, Ye; Fu, Lixin; Wang, Shuxiao; Zhang, Shaojun; Hao, Jiming

    2012-09-01

    The intake fraction (iF) is the portion of attributable population intake of a source emissions, and is used to link pollutant emissions and population exposure. This study is the first work that reported individual intake fraction of PM2.5 and NOX from vehicle emissions based on personal exposure data in China. We employed PM2.5 and NOX measurement data from 24-h personal exposure sampling and concentration monitoring in traffic environments in the urban area of Beijing to estimate the individual intake fraction (iFi). iFi distributions are presented in microenvironments (traffic, work, home) for adults and children. The individual results are used to calculate the intake fraction for the children group and the adults group in the urban area of Beijing. The iF of PM2.5 for the whole population of these two groups in Beijing is 153 per million, which is significantly higher than those estimates in the United States (1-50 per million) and Mexico (23-120 per million). The iF of NOX is 70 per million, among which the intake in the traffic micro-environment ranks first compared to the iF in the home and office due to a high accumulation of NOX concentration in vehicles. PM2.5 and NOX intake fraction values from vehicle emissions in this study are from at least several times to one order of magnitude higher than those from other industry sources in China. This strongly suggests the health risk from vehicle emissions is significantly higher. Therefore, to protect human health, especially for the large number of people living in the cities of China, controlling vehicle emissions should be the highest priority.

  14. Lifting business process diagrams to 2.5 dimensions

    NASA Astrophysics Data System (ADS)

    Effinger, Philip; Spielmann, Johannes

    2010-01-01

    In this work, we describe our visualization approach for business processes using 2.5 dimensional techniques (2.5D). The idea of 2.5D is to add the concept of layering to a two dimensional (2D) visualization. The layers are arranged in a three-dimensional display space. For the modeling of the business processes, we use the Business Process Modeling Notation (BPMN). The benefit of connecting BPMN with a 2.5D visualization is not only to obtain a more abstract view on the business process models but also to develop layering criteria that eventually increase readability of the BPMN model compared to 2D. We present a 2.5D Navigator for BPMN models that offers different perspectives for visualization. Therefore we also develop BPMN specific perspectives. The 2.5D Navigator combines the 2.5D approach with perspectives and allows free navigation in the three dimensional display space. We also demonstrate our tool and libraries used for implementation of the visualizations. The underlying general framework for 2.5D visualizations is explored and presented in a fashion that it can easily be used for different applications. Finally, an evaluation of our navigation tool demonstrates that we can achieve satisfying and aesthetic displays of diagrams stating BPMN models in 2.5D-visualizations.

  15. An update on 2,5-diketopiperazines from marine organisms.

    PubMed

    Huang, Ri-Ming; Yi, Xiang-Xi; Zhou, Yuying; Su, Xiangdong; Peng, Yan; Gao, Cheng-Hai

    2014-12-01

    2,5-Diketopiperazines (2,5-DKPs) are an important category of structurally diverse cyclic dipeptides with prominent biological properties. These 2,5-DKPs have been obtained from a variety of natural resources, including marine organisms. Because of the increasing numbers and biological importance of these compounds, this review covers 90 marine originated 2,5-DKPs that were reported from 2009 to the first half-year of 2014. The review will focus on the structure characterizations, biological properties and proposed biosynthetic processes of these compounds. PMID:25532564

  16. Maintaining Quality in Troubled Times. Pacific Rim Association for Higher Education Annual Conference (2nd, Seattle, Washington, October 13-14, 1981).

    ERIC Educational Resources Information Center

    Pacific Rim Association for Higher Education.

    Proceedings of the Pacific Rim Association for Higher Education 1981 conference are summarized. Authors and the summarized papers are as follows: "Maintaining Quality in Troubled Times: The University Perspective" (George M. Beckmann); "Maintaining Quality in Troubled Times: The Community College Perspective" (Don A. Morgan); "Report from China"…

  17. The Hidden Benefits of Part-Time Higher Education Study to Working Practices: Is There a Case for Making Them More Visible?

    ERIC Educational Resources Information Center

    Callender, Claire; Little, Brenda

    2015-01-01

    Within the UK, part-time study is now seen as important in meeting wider government objectives for higher education (HE) and for sustainable economic growth through skills development. Yet, measures to capture the impact of HE may not be wholly appropriate to part-time study. In particular, the continuing focus on tangible, economic measures may…

  18. Correlation between microstructure and charge transport in poly(2,5-dimethoxy- p -phenylenevinylene) thin films

    NASA Astrophysics Data System (ADS)

    Sims, M.; Tuladhar, S. M.; Nelson, J.; Maher, R. C.; Campoy-Quiles, M.; Choulis, S. A.; Mairy, M.; Bradley, D. D. C.; Etchegoin, P. G.; Tregidgo, C.; Suhling, K.; Richards, D. R.; Massiot, P.; Nielsen, C. B.; Steinke, J. H. G.

    2007-11-01

    We report a study of thin films of poly(2,5-dimethoxy- p -phenylenevinylene) (PDMeOPV) prepared by a precursor route. Conversion at two different temperatures, namely, 120 and 185°C , produces partially and fully converted films. We study the structural, optical, and charge transport characteristics of these samples in order to relate transport properties to microstructure. Micro-Raman mapping and photoluminescence (PL) imaging reveal the existence of coarse, depth-averaged domains of around 50μm in lateral extent, with more pronounced contrast for conversion at the higher temperature. The contrast in both micro-Raman and PL maps can be attributed to fluctuations in film density. Spectroscopic ellipsometry studies of the films indicate that the average film density is approximately 15% higher for conversion at the higher temperature. Time-of-flight photocurrent transients, recorded here in PDMeOPV films, are typically dispersive but yield hole mobilities in excess of 10-4cm2/Vs at modest applied fields (˜1.2×105V/cm) in the fully converted films. To our knowledge, these are amongst the highest reported mobility values for a poly( p -phenylenevinylene) derivative. Fully converted films, while yielding higher hole mobilities, exhibit a stronger dependence on electric field than partially converted ones. The higher mobility can be attributed to the almost complete conversion of the flexible saturated subunits within precursor chains to conjugated vinylene moieties at elevated temperature. This results in a correspondingly higher packing density, an improvement in intrachain transport, and a reduction in the smallest interchain hopping distance. We suggest that the stronger electric field dependence is due to the increasing influence of intermolecular electrostatic interactions with decreasing interchain separation. We propose that a greater proportion of chains in the fully converted films packs in a three-dimensional, interdigitated arrangement similar to that

  19. Ambient temperature enhanced acute cardiovascular-respiratory mortality effects of PM2.5 in Beijing, China

    NASA Astrophysics Data System (ADS)

    Li, Yi; Ma, Zhiqiang; Zheng, Canjun; Shang, Yu

    2015-12-01

    Studies have shown that temperature could modify the effect of ambient fine particles on mortality risk. In assessing air pollution effects, temperature is usually considered as a confounder. However, ambient temperature can alter people's physiological response to air pollution and might "modify" the impact of air pollution on health outcomes. This study investigated the interaction between daily PM2.5 and daily mean temperature in Beijing, China, using data for the period 2005-2009. Bivariate PM2.5-temperature response surfaces and temperature-stratified generalized additive model (GAM) were applied to study the effect of PM2.5 on cardiovascular, respiratory mortality, and total non-accidental mortality across different temperature levels. We found that low temperature could significantly enhance the effect of PM2.5 on cardiovascular mortality. For an increase of 10 μg/m3 in PM2.5 concentration in the lowest temperature range (-9.7˜2.6 °C), the relative risk (RR) of cardiovascular mortality increased 1.27 % (95 % CI 0.38˜2.17 %), which was higher than that of the whole temperature range (0.59 %, 95 % CI 0.22-1.16 %). The largest effect of PM2.5 on respiratory mortality appeared in the high temperature range. For an increase of 10 μg/m3 in PM2.5 concentration, RR of respiratory mortality increased 1.70 % (95 % CI 0.92˜3.33 %) in the highest level (23.50˜31.80 °C). For the total non-accidental mortality, significant associations appeared only in low temperature levels (-9.7˜2.6 °C): for an increase of 10 μg/m3 in current day PM2.5 concentration, RR increased 1.27 % (95 % CI 0.46˜2.00 %) in the lowest temperature level. No lag effect was observed. The results suggest that in air pollution mortality time series studies, the possibility of an interaction between air pollution and temperature should be considered.

  20. Ambient temperature enhanced acute cardiovascular-respiratory mortality effects of PM2.5 in Beijing, China.

    PubMed

    Li, Yi; Ma, Zhiqiang; Zheng, Canjun; Shang, Yu

    2015-12-01

    Studies have shown that temperature could modify the effect of ambient fine particles on mortality risk. In assessing air pollution effects, temperature is usually considered as a confounder. However, ambient temperature can alter people's physiological response to air pollution and might "modify" the impact of air pollution on health outcomes. This study investigated the interaction between daily PM2.5 and daily mean temperature in Beijing, China, using data for the period 2005-2009. Bivariate PM2.5-temperature response surfaces and temperature-stratified generalized additive model (GAM) were applied to study the effect of PM2.5 on cardiovascular, respiratory mortality, and total non-accidental mortality across different temperature levels. We found that low temperature could significantly enhance the effect of PM2.5 on cardiovascular mortality. For an increase of 10 μg/m(3) in PM2.5 concentration in the lowest temperature range (-9.7∼2.6 °C), the relative risk (RR) of cardiovascular mortality increased 1.27 % (95 % CI 0.38∼2.17 %), which was higher than that of the whole temperature range (0.59 %, 95 % CI 0.22-1.16 %). The largest effect of PM2.5 on respiratory mortality appeared in the high temperature range. For an increase of 10 μg/m(3) in PM2.5 concentration, RR of respiratory mortality increased 1.70 % (95 % CI 0.92∼3.33 %) in the highest level (23.50∼31.80 °C). For the total non-accidental mortality, significant associations appeared only in low temperature levels (-9.7∼2.6 °C): for an increase of 10 μg/m(3) in current day PM2.5 concentration, RR increased 1.27 % (95 % CI 0.46∼2.00 %) in the lowest temperature level. No lag effect was observed. The results suggest that in air pollution mortality time series studies, the possibility of an interaction between air pollution and temperature should be considered.

  1. 2.5-D modeling in electromagnetic methods of geophysics

    NASA Astrophysics Data System (ADS)

    Tabarovsky, L. A.; Goldman, M. M.; Rabinovich, M. B.; Strack, K.-M.

    1996-10-01

    Understanding, using, or eliminating three-dimensional (3-D) effects in electromagnetic methods of geophysics are critical requirements. Numerous achievements in 3-D modeling sometimes give the impression that they are widely available today in geophysical practice. This is not necessarily true. Existing 3-D modeling packages prove that we know how to perform 3-D modeling. However, the computer resources and costs involved make the practical application of 3-D EM modeling in geophysical applications very limited. A practical compromise, or even alternative, is represented by 2.5-D modeling characterized by the use of a 3-D source in a 2-D medium. This combination allows one to mathematically describe the related boundary value problem as a sequence of independent two-dimensional problems. The typical technique leading to such a split formulation is Fourier analysis. That is why the individual terms of a split solution are often referred to as harmonics. Although each independent problem is two-dimensional, the algorithmic implementation of finite differences or integral equations for the higher harmonics has some specific features not present in the classical 2-D cases. In this paper, a hybrid scheme consisting of a combination of the finite difference technique with the integral equation approach for transient fields is described. Evaluation of algorithm accuracy is presented and a transient logging technique application is considered. The algorithm is fast and easily implemented on a personal computer

  2. A television in the bedroom is associated with higher weekday screen time among youth with attention deficit hyperactivity disorder (ADD/ADHD)

    PubMed Central

    Lo, Charmaine B.; Waring, Molly E.; Pagoto, Sherry L.; Lemon, Stephenie C.

    2014-01-01

    Objective A TV in the bedroom has been associated with screen time in youth. Youth with attention deficit hyperactivity disorder (ADD/ADHD) have higher rates of screen time, but associations with bedroom TVs are unknown in this population. We examined the association of having a bedroom TV with screen time among youth with ADD/ADHD. Methods Data were from the 2007 National Survey of Children's Health. Youth 6–17 years whose parent/guardian reported a physician's diagnosis of ADD/ADHD (n = 7024) were included in the analysis. Parents/guardians reported the presence of a bedroom TV and average weekday TV screen time. Multivariate linear and logistic regression models assessed the effects of a bedroom on screen time. Results Youth with ADD/ADHD engaged in screen time with an average of 149.1 min/weekday and 59% had a TV in their bedroom. Adjusting for child and family characteristics, having a TV in the bedroom was associated with 25 minute higher daily screen time (95% CI: 12.8–37.4 min/day). A bedroom TV was associated with 32% higher odds of engaging in screen time for over 2 h/day (OR = 1.3; 95% CI: 1.0–1.7). Conclusion Future research should explore whether removing TVs from bedrooms reduces screen time among youth with ADD/ADHD. PMID:25599016

  3. Influence of meteorological conditions on PM 2.5 and PM 2.5-10 concentrations during the monsoon season in Hanoi, Vietnam

    NASA Astrophysics Data System (ADS)

    Hien, P. D.; Bac, V. T.; Tham, H. C.; Nhan, D. D.; Vinh, L. D.

    Twenty-four hour samples of air particulate matter with aerodynamic diameters from 2 to 10 μm (PM 10) and <2.5 μm (PM 2.5) were collected in Hanoi throughout 1 year since August 1998. The air sampler was located in a meteorological garden where routine surface observations and upper air radiosoundings were conducted. Very high PM 2.5 and PM 2.5-10 concentrations were observed in conjunction with the occurrence of nocturnal radiation inversions from October to December and subsidence temperature inversions (STI) from January to March. In the first case, the PM 2.5-10 fraction was much enhanced and particulate pollution was significantly higher at night than in daytime. During the occurence of STIs particulate mass was almost evenly distributed among the two fractions and no significant diurnal variations in concentrations were observed. In summer (May-September) particulate pollution was much lower than in winter. The multiple regression of 24-h particulate concentrations against meteorological parameters for both the winter and summer monsoon periods shows that the most important determinants of PM 2.5 are wind speed and air temperature, while rainfall and relative humidity largely control the daily variations of PM 2.5-10, indicating the high abundance of soil dust in this fraction. As to turbulence parameters, among the determinants of 24-h particulate concentrations are the vertical gradients of potential temperature and wind speed recorded at 06.30 and 18.30, respectively. Meteorological parameters could explain from 60% to 74% of the day-to-day variations of particulate concentrations.

  4. Photochemistry Of 2,5-Diacyl-1, 4-Dimethylbenzenes

    NASA Technical Reports Server (NTRS)

    Meador, Michael A.

    1989-01-01

    Experiments described in report revealed potentially useful aspects of photochemistry of 2,5-dibenzoyl-1, 4-dimethylbenzene (DBX) and 2,5-diacetyl-1, 4-dimethylbenzene (DAX). Behavior of these compounds reminiscent of orthoalkylphenyl ketones, studied from similar perspective for more than two decades.

  5. 14 CFR Sec. 2-5 - Revenue and accounting practices.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Revenue and accounting practices. Sec. 2-5... General Accounting Provisions Sec. 2-5 Revenue and accounting practices. (a) Revenue accounting practices... physically verify the reliability of its passenger revenue accounting practice at least once each...

  6. 43 CFR 3861.2-5 - Amended mineral surveys.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false Amended mineral surveys. 3861.2-5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL PATENT APPLICATIONS Surveys and Plats § 3861.2-5 Amended mineral surveys. (a) Inasmuch as amended surveys are ordered only by...

  7. 43 CFR 3861.2-5 - Amended mineral surveys.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Amended mineral surveys. 3861.2-5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL PATENT APPLICATIONS Surveys and Plats § 3861.2-5 Amended mineral surveys. (a) Inasmuch as amended surveys are ordered only by...

  8. 43 CFR 3861.2-5 - Amended mineral surveys.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Amended mineral surveys. 3861.2-5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL PATENT APPLICATIONS Surveys and Plats § 3861.2-5 Amended mineral surveys. (a) Inasmuch as amended surveys are ordered only by...

  9. 43 CFR 3861.2-5 - Amended mineral surveys.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false Amended mineral surveys. 3861.2-5 Section... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) MINERAL PATENT APPLICATIONS Surveys and Plats § 3861.2-5 Amended mineral surveys. (a) Inasmuch as amended surveys are ordered only by...

  10. 10 CFR 960.5-2-5 - Environmental quality.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Environmental quality. 960.5-2-5 Section 960.5-2-5 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE... in the affected area during this and future generations will be adequately protected...

  11. 10 CFR 960.5-2-5 - Environmental quality.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Environmental quality. 960.5-2-5 Section 960.5-2-5 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE... in the affected area during this and future generations will be adequately protected...

  12. Intra-urban spatial variability of PM2.5-bound carbonaceous components

    PubMed Central

    Xie, Mingjie; Coons, Teresa L.; Dutton, Steven J.; Milford, Jana B.; Miller, Shelly L.; Peel, Jennifer L.; Vedal, Sverre; Hannigan, Michael P.

    2014-01-01

    The Denver Aerosol Sources and Health (DASH) study was designed to evaluate associations between PM2.5 species and sources and adverse human health effects. The DASH study generated a five-year (2003–2007) time series of daily speciated PM2.5 concentration measurements from a single, special-purpose monitoring site in Denver, CO. To evaluate the ability of this site to adequately represent the short term temporal variability of PM2.5 concentrations in the five county Denver metropolitan area, a one year supplemental set of PM2.5 samples was collected every sixth day at the original DASH monitoring site and concurrently at three additional sites. Two of the four sites, including the original DASH site, were located in residential areas at least 1.9 km from interstate highways. The other two sites were located within 0.3 km of interstate highways. Concentrations of elemental carbon (EC), organic carbon (OC), and 58 organic molecular markers were measured at each site. To assess spatial variability, site pairs were compared using the Pearson correlation coefficient (r) and coefficient of divergence (COD), a statistic that provides information on the degree of uniformity between monitoring sites. Biweekly co-located samples collected from July 2004 to September 2005 were also analyzed and used to estimate the uncertainty associated with sampling and analytical measurement for each species. In general, the two near-highway sites exhibited higher concentrations of EC, OC, polycyclic aromatic hydrocarbons (PAHs), and steranes than did the more residential sites. Lower spatial heterogeneity based on r and COD was inferred for all carbonaceous species after considering their divergence and lack of perfect correlations in co-located samples. Ratio–ratio plots combined with available gasoline- and diesel-powered motor vehicle emissions profiles for the region suggested a greater impact to high molecular weight (HMW) PAHs from diesel-powered vehicles at the near

  13. Determinants of exposure to fine particulate matter (PM 2.5) for waiting passengers at bus stops

    NASA Astrophysics Data System (ADS)

    Hess, Daniel Baldwin; Ray, Paul David; Stinson, Anne E.; Park, JiYoung

    2010-12-01

    This research evaluates commuter exposure to particulate matter during pre-journey commute segments for passengers waiting at bus stops by investigating 840 min of simultaneous exposure levels, both inside and outside seven bus shelters in Buffalo, New York. A multivariate regression model is used to estimate the relation between exposure to particulate matter (PM 2.5 measured in μg m -3) and three vectors of determinants: time and location, physical setting and placement, and environmental factors. Four determinants have a statistically significant effect on particulate matter: time of day, passengers' waiting location, land use near the bus shelter, and the presence of cigarette smoking at the bus shelter. Model results suggest that exposure to PM 2.5 inside a bus shelter is 2.63 μg m -3 (or 18 percent) higher than exposure outside a bus shelter, perhaps due in part to the presence of cigarette smoking. Morning exposure levels are 6.51 μg m -3 (or 52 percent) higher than afternoon levels. Placement of bus stops can affect exposure to particulate matter for those waiting inside and outside of shelters: air samples at bus shelters located in building canyons have higher particulate matter than bus shelters located near open space.

  14. Flexible Pedagogies: Part-Time Learners and Learning in Higher Education. Flexible Pedagogies: Preparing for the Future Series

    ERIC Educational Resources Information Center

    McLinden, Michael

    2013-01-01

    This publication focuses on national and international policy initiatives to develop a better understanding of part-time learners and the types of flexibility that may enhance their study especially pedagogically. As part of our five-strand research project "Flexible Pedagogies: preparing for the future" it: (1) highlights the challenges…

  15. The Economic Domino Effect: A Phenomenological Study Exploring Community College Faculty's Lived Experiences during Financial Hard Times in Higher Education

    ERIC Educational Resources Information Center

    Taylor, Tridai A.

    2014-01-01

    This qualitative study explored the lived experiences of eight full-time community college faculty members who taught during the economic crisis of 2008. The study was guided by the central research question, "How do community college faculty members describe their lived experiences regarding the recent economic crisis of 2008 and its impact…

  16. Recruitment and Retention of Full-Time Engineering Faculty, Fall 1980. Higher Education Panel Report Number 52.

    ERIC Educational Resources Information Center

    Atelsek, Frank J.; Gomberg, Irene L.

    The extent of faculty vacancies in colleges of engineering, the effects of such vacancies upon research and instructional programs, and the nature of the competition between academia and industry in hiring engineering faculty were surveyed. The focus is on permanent full-time faculty positions in the following major engineering fields:…

  17. Does a Higher Incidence of Break Times in Primary Schools Result in Children Being More Physically Active?

    ERIC Educational Resources Information Center

    Kobel, Susanne; Kettner, Sarah; Erkelenz, Nanette; Kesztyüs, Dorothea; Steinacker, Jürgen M.

    2015-01-01

    Background: Regular physical activity (PA) has multiple benefits to health; however, the majority of schoolchildren do not reach PA guidelines of 60 minutes of moderate to vigorous PA (MVPA) daily. During the school day, break times are often the only opportunity for children to be physically active. This study investigated PA levels during school…

  18. PM2.5 and mortality in long-term prospective cohort studies: cause-effect or statistical associations?

    PubMed Central

    Gamble, J F

    1998-01-01

    Concentrations of ambient PM2.5 (particulate matter <2.5 microm in aerodynamic diameter) were associated with increased mortality in two prospective cohort studies. In this paper, I assess whether the weight of the evidence supports a causal association. I assumed the study population in each city to have the same exposure; therefore, these are ecologic studies because exposure is at the group level. Health outcome and confounding data are at the individual level. Ambient PM concentrations are inadequate surrogates for personal exposure because they are at the group level and comprise only a small proportion of personal exposure, they change over time, and they constitute only a small proportion of a life span. The strength of association and exposure-response relationships cannot be determined because the ecologic group-level risks of PM2.5 are overestimated 150- to 300-fold based on an analogy with individual-level exposure to inhaled cigarette smoke. Risk estimates may also be high because of confounding from factors such as physical activity and lung function. The evidence is not coherent because the stronger associations are expected to be with morbidity, but instead are with mortality. For example, PM2.5 was associated with mortality but not with measurable reductions in lung function. Biological plausibility is lacking because lifetime exposure of rats to combustion products at concentrations two to three orders of magnitude higher than air pollution levels cause lung overloading but no consistent reduction in survival. Criteria for quantitative risk assessment are not met so the data are not useful for setting air quality standards. The weight of evidence suggests there is no substantive basis for concluding that a cause-effect relationship exists between long-term ambient PM2.5 and increased mortality. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 PMID:9721253

  19. Synthesis of 2,5-Dichloro-2,5-Dimethylhexane by an S[subscript N]1 Reaction

    ERIC Educational Resources Information Center

    Wagner, Carl E.; Marshall, Pamela A.

    2010-01-01

    This laboratory experiment was developed to provide a safe, economical, and effective way to instruct undergraduate organic chemistry students about the unimolecular nucleophilic substitution (S[subscript N]1) reaction. Students treat 2,5-dimethyl-2,5-hexanediol with excess concentrated hydrochloric acid to synthesize…

  20. Fine particulate (PM2.5) dynamics during rapid urbanization in Beijing, 1973–2013

    PubMed Central

    Han, Lijian; Zhou, Weiqi; Li, Weifeng

    2016-01-01

    PM2.5 has been given special concern in recent years when the air quality monitoring station started recording. However, long-term PM2.5 concentration dynamic analysis cannot be taken with the limited observations. We therefore estimated the PM2.5 concentration using meteorological visibility data in Beijing. We found that 71 ± 17% of PM10 were PM2.5, which contributed to visibility impairment (y = 332.26e−0.232x; R2 = 0.75, P < 0.05). We then reconstructed a time series of annual PM2.5 from 1973 to 2013, and examined its relationship with urbanization by indicators of population, gross domestic production (GDP), energy consumption, and number of vehicles. Concluded that 1) Meteorological conditions were not the major cause of PM2.5 increase from 1973 to 2013; 2) With population and GDP growth, PM2.5 increased significantly (R2 = 0.5917, P < 0.05; R2 = 0.5426, P < 0.05); 3) Intensive human activity could change air quality in a short period, as observed changes in the correlations of PM2.5 concentration with energy consumption and number of vehicles before and after 2004, respectively. The success of this research provides an easy way in reconstructing long-term PM2.5 concentration with limited PM2.5 observation and meteorological visibility, and insight the impact of urbanization on air quality. PMID:27031598

  1. Fine particulate (PM2.5) dynamics during rapid urbanization in Beijing, 1973-2013

    NASA Astrophysics Data System (ADS)

    Han, Lijian; Zhou, Weiqi; Li, Weifeng

    2016-03-01

    PM2.5 has been given special concern in recent years when the air quality monitoring station started recording. However, long-term PM2.5 concentration dynamic analysis cannot be taken with the limited observations. We therefore estimated the PM2.5 concentration using meteorological visibility data in Beijing. We found that 71 ± 17% of PM10 were PM2.5, which contributed to visibility impairment (y = 332.26e-0.232x R2 = 0.75, P < 0.05). We then reconstructed a time series of annual PM2.5 from 1973 to 2013, and examined its relationship with urbanization by indicators of population, gross domestic production (GDP), energy consumption, and number of vehicles. Concluded that 1) Meteorological conditions were not the major cause of PM2.5 increase from 1973 to 2013; 2) With population and GDP growth, PM2.5 increased significantly (R2 = 0.5917, P < 0.05 R2 = 0.5426, P < 0.05) 3) Intensive human activity could change air quality in a short period, as observed changes in the correlations of PM2.5 concentration with energy consumption and number of vehicles before and after 2004, respectively. The success of this research provides an easy way in reconstructing long-term PM2.5 concentration with limited PM2.5 observation and meteorological visibility, and insight the impact of urbanization on air quality.

  2. Fine particulate (PM2.5) dynamics during rapid urbanization in Beijing, 1973-2013.

    PubMed

    Han, Lijian; Zhou, Weiqi; Li, Weifeng

    2016-03-31

    PM2.5 has been given special concern in recent years when the air quality monitoring station started recording. However, long-term PM2.5 concentration dynamic analysis cannot be taken with the limited observations. We therefore estimated the PM2.5 concentration using meteorological visibility data in Beijing. We found that 71 ± 17% of PM10 were PM2.5, which contributed to visibility impairment (y = 332.26e(-0.232x); R(2) = 0.75, P < 0.05). We then reconstructed a time series of annual PM2.5 from 1973 to 2013, and examined its relationship with urbanization by indicators of population, gross domestic production (GDP), energy consumption, and number of vehicles. Concluded that 1) Meteorological conditions were not the major cause of PM2.5 increase from 1973 to 2013; 2) With population and GDP growth, PM2.5 increased significantly (R(2) = 0.5917, P < 0.05; R(2) = 0.5426, P < 0.05); 3) Intensive human activity could change air quality in a short period, as observed changes in the correlations of PM2.5 concentration with energy consumption and number of vehicles before and after 2004, respectively. The success of this research provides an easy way in reconstructing long-term PM2.5 concentration with limited PM2.5 observation and meteorological visibility, and insight the impact of urbanization on air quality.

  3. Fine particulate (PM2.5) dynamics during rapid urbanization in Beijing, 1973–2013

    NASA Astrophysics Data System (ADS)

    Han, Lijian; Zhou, Weiqi; Li, Weifeng

    2016-03-01

    PM2.5 has been given special concern in recent years when the air quality monitoring station started recording. However, long-term PM2.5 concentration dynamic analysis cannot be taken with the limited observations. We therefore estimated the PM2.5 concentration using meteorological visibility data in Beijing. We found that 71 ± 17% of PM10 were PM2.5, which contributed to visibility impairment (y = 332.26e‑0.232x R2 = 0.75, P < 0.05). We then reconstructed a time series of annual PM2.5 from 1973 to 2013, and examined its relationship with urbanization by indicators of population, gross domestic production (GDP), energy consumption, and number of vehicles. Concluded that 1) Meteorological conditions were not the major cause of PM2.5 increase from 1973 to 2013; 2) With population and GDP growth, PM2.5 increased significantly (R2 = 0.5917, P < 0.05 R2 = 0.5426, P < 0.05) 3) Intensive human activity could change air quality in a short period, as observed changes in the correlations of PM2.5 concentration with energy consumption and number of vehicles before and after 2004, respectively. The success of this research provides an easy way in reconstructing long-term PM2.5 concentration with limited PM2.5 observation and meteorological visibility, and insight the impact of urbanization on air quality.

  4. Fine particulate (PM2.5) dynamics during rapid urbanization in Beijing, 1973-2013.

    PubMed

    Han, Lijian; Zhou, Weiqi; Li, Weifeng

    2016-01-01

    PM2.5 has been given special concern in recent years when the air quality monitoring station started recording. However, long-term PM2.5 concentration dynamic analysis cannot be taken with the limited observations. We therefore estimated the PM2.5 concentration using meteorological visibility data in Beijing. We found that 71 ± 17% of PM10 were PM2.5, which contributed to visibility impairment (y = 332.26e(-0.232x); R(2) = 0.75, P < 0.05). We then reconstructed a time series of annual PM2.5 from 1973 to 2013, and examined its relationship with urbanization by indicators of population, gross domestic production (GDP), energy consumption, and number of vehicles. Concluded that 1) Meteorological conditions were not the major cause of PM2.5 increase from 1973 to 2013; 2) With population and GDP growth, PM2.5 increased significantly (R(2) = 0.5917, P < 0.05; R(2) = 0.5426, P < 0.05); 3) Intensive human activity could change air quality in a short period, as observed changes in the correlations of PM2.5 concentration with energy consumption and number of vehicles before and after 2004, respectively. The success of this research provides an easy way in reconstructing long-term PM2.5 concentration with limited PM2.5 observation and meteorological visibility, and insight the impact of urbanization on air quality. PMID:27031598

  5. Seasonal variations and chemical characteristics of PM(2.5) in Wuhan, central China.

    PubMed

    Zhang, Fan; Wang, Zu-wu; Cheng, Hai-rong; Lv, Xiao-pu; Gong, Wei; Wang, Xin-ming; Zhang, Gan

    2015-06-15

    PM2.5 samples were collected at an urban site (WD) and a suburban site (TH) in Wuhan from August 2012 to July 2013. The mass concentrations of water-soluble inorganic ions, carbonaceous species and elements of PM2.5 were measured. The annual mean concentrations of PM2.5 were 106.5 μg/m(3) and 114.9 μg/m(3) at WD and TH, respectively. The chemical compositions of PM2.5 at WD were similar to those at TH and the fractions of the major components of PM2.5 in Wuhan were in the following order of trace elements2.5, the lowest concentrations of which were observed in summer at both sites, while the highest concentrations of OC (organic carbon) appeared in winter at WD and autumn at TH, respectively. The highest OC concentration observed in autumn was tightly related to the biomass burning near the suburban site. The crustal elements (Mg, K, Ca and Fe) dominated the 20 detected elements in PM2.5, with the highest concentrations in spring in Wuhan, which might be due to frequent sandstorm from north carrying abundant soil dusts in spring in China. Ten trace elements (Cu, Ga, Ag, Tl, Ca, As, Zn, Pb, Se and Cd) were enriched in PM2.5 and the higher EF for Ag, Pb, Se and Cd in PM2.5 indicated that the air pollution from vehicle exhaust emission and coal burning in Wuhan was serious and noteworthy. PMID:25747369

  6. Effects of shisha smoking on carbon monoxide and PM2.5 concentrations in the indoor and outdoor microenvironment of shisha premises.

    PubMed

    Gurung, Gam; Bradley, Janet; Delgado-Saborit, Juana Maria

    2016-04-01

    There has been significant rise in shisha premises in the United Kingdom with an unsubstantiated belief that shisha smoking is harmless and relatively safe. This study aimed to assess the public health situation by evaluating the extent of shisha environmental tobacco smoke (ETS) exposure among those that work in, and are customers of shisha businesses. Concentrations of several ETS pollutants such as carbon monoxide (CO) and particulate matter with a diameter of less than 2.5μm (PM2.5) in shisha premises were measured using real-time sensors inside and outside twelve shisha premises and at 5 pubs/restaurants where smoking is prohibited. Mean concentration of CO (7.3±2.4mg/m(3)) and PM2.5 (287±233μg/m(3)) inside active shisha premises was higher than concentrations measured within the vicinity of the shisha premises (CO: 0.9±0.7mg/m(3) and PM2.5: 34±14μg/m(3)) and strongly correlated (PM2.5 R=0.957). Concentrations were higher than indoor concentrations in pubs and restaurants where smoking is not permitted under UK law. The number of shisha pipes was a strong predictor of the PM2.5 concentrations. The study also assessed the risk perception within patrons and managers, with only 25% being aware of the risks associated to shisha smoking. The study identifies owners, employees and consumers within active shisha premises being exposed to concentrations of CO and PM2.5 at levels considered hazardous to human health. The results and outcome of this research serve as a basis to influence a discussion around the need of developing specific policies to protect consumers and employees of such premises.

  7. Effects of shisha smoking on carbon monoxide and PM2.5 concentrations in the indoor and outdoor microenvironment of shisha premises.

    PubMed

    Gurung, Gam; Bradley, Janet; Delgado-Saborit, Juana Maria

    2016-04-01

    There has been significant rise in shisha premises in the United Kingdom with an unsubstantiated belief that shisha smoking is harmless and relatively safe. This study aimed to assess the public health situation by evaluating the extent of shisha environmental tobacco smoke (ETS) exposure among those that work in, and are customers of shisha businesses. Concentrations of several ETS pollutants such as carbon monoxide (CO) and particulate matter with a diameter of less than 2.5μm (PM2.5) in shisha premises were measured using real-time sensors inside and outside twelve shisha premises and at 5 pubs/restaurants where smoking is prohibited. Mean concentration of CO (7.3±2.4mg/m(3)) and PM2.5 (287±233μg/m(3)) inside active shisha premises was higher than concentrations measured within the vicinity of the shisha premises (CO: 0.9±0.7mg/m(3) and PM2.5: 34±14μg/m(3)) and strongly correlated (PM2.5 R=0.957). Concentrations were higher than indoor concentrations in pubs and restaurants where smoking is not permitted under UK law. The number of shisha pipes was a strong predictor of the PM2.5 concentrations. The study also assessed the risk perception within patrons and managers, with only 25% being aware of the risks associated to shisha smoking. The study identifies owners, employees and consumers within active shisha premises being exposed to concentrations of CO and PM2.5 at levels considered hazardous to human health. The results and outcome of this research serve as a basis to influence a discussion around the need of developing specific policies to protect consumers and employees of such premises. PMID:26803732

  8. CUMULATIVE PM2.5 EXPOSURE AND TELOMERE LENGTH IN WORKERS EXPOSED TO WELDING FUMES

    PubMed Central

    Wong, Jason Y. Y.; De Vivo, Immaculata; Lin, Xihong; Christiani, David C.

    2014-01-01

    Telomeres are genomic structures that reflect both mitotic history and biochemical trauma to the genome. Metals inherent in fine particulate matter (PM2.5) were shown to be genotoxic via oxidative damage. However, few studies investigated the induction time of cumulative PM2.5 exposure on telomere length in a longitudinal setting. Therefore, the purpose of this study was to assess the association between occupational PM2.5 exposure in various time windows and telomere length. The study population consisted of 48 boilermakers and the follow-up period was 8 yr. The main exposures were cumulative occupational PM2.5 in the month, year, and career prior to each blood draw, assessed via work history questionnaires and area air measures. Repeated telomere length measurements from leukocytes were assessed via real-time quantitative polymerase chain reaction (qPCR). Analysis was performed using linear mixed models controlling for confounders and white blood cell differentials. Cumulative PM2.5 exposure was treated continuously and categorized into quartiles, in separate analyses. At any follow-up time, for each milligram per cubic meter per hour increase in cumulative PM2.5 exposure in the prior month, there was a statistically significant decrease in relative telomere length of −0.04 units. When categorizing the exposure into quartiles, there was a significant negative association between telomere length and highest quartile of cumulative PM2.5 exposure in the prior month (−0.16). These findings suggest that genomic trauma to leukocyte telomeres was more consistent with recent occupational PM2.5 exposure, as opposed to cumulative exposure extending into the distant past. PMID:24627998

  9. Unfolding ESIPT in Bis-2,5-(2-benzoxazolyl) Hydroquinone and 2,5-Bis(benzo[d]oxazol-2-yl)-4-methoxyphenol: a Comprehensive Computational Approach.

    PubMed

    Jadhav, Manoj M; Rhyman, Lydia; Ramasami, Ponnadurai; Sekar, Nagaiyan

    2016-07-01

    The photo-physical behaviour of bis-2,5-(2-benzoxazolyl) hydroquinone and 2,5-bis (benzo[d]oxazol-2-yl)-4-methoxyphenol was studied using the Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT). All the possible rotamers were optimized to obtain global minimum optimized structure. The theoretical absorption and emission values of rotamers estimated by using TD-DFT [TD-B3LYP/6-31G(d)] are in good agreement with experimental absorption and emission wavelengths. Based on the absorption values, the contribution of respective rotamer is determined theoretically.

  10. Physico-chemical characterization of PM2.5 in the microenvironment of Shanghai subway

    NASA Astrophysics Data System (ADS)

    Lu, Senlin; Liu, Dingyu; Zhang, Wenchao; Liu, Pinwei; Fei, Yi; Gu, Yan; Wu, Minghong; Yu, Shang; Yonemochi, Shinich; Wang, Xiaoju; Wang, Qingyue

    2015-02-01

    The Shanghai subway metro system has brought great convenience to the city's travelling public, although passengers are exposed to airborne particles in this built micro-environment. However, investigations on the physicochemical characterization of PM2.5 air pollution in the Shanghai subway system are to date very limited. Three subway stations along the No. 7 line were selected as subway PM2.5 monitoring sites: Pan'guang, Shanghai University (SHU), and Jing'an, which are located in an outer suburban area, a suburban area and the urban area, respectively, airborne PM2.5 on the subway station platforms and in the ambient atmosphere above-ground was synchronously collected from 19th March to 4th, May, 2012. Cutting-edge techniques, including scanning electronic microscopy coupled with energy dispersive X-ray (SEM/EDX), inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge structure (XANES) were employed to investigate microscopic characterization, chemical elements and speciation of the main heavy metals in subway PM2.5. Our results demonstrated that mass levels of PM2.5 in the subway stations were higher than that in ambient air. Mass levels of PM2.5 in the subway stations and in ambient air ranged from 49.17 ± 19.7 μg/m3 to 66.15 ± 25.20 μg/m3, and 24.52 ± 3.3 μg/m3 to 65.60 ± 5.6 μg/m3, respectively. The microscopic characterization of PM2.5 in ambient air and in subway stations showed marked differences. The PM2.5 in the subway stations was mainly composed of iron-containing particles and mineral particles, while the PM2.5 in ambient air largely consisted of mineral particles and soot aggregates. Fe was the most abundant element in subway PM2.5, followed by: major elements (mass level > 100 ng/m3) including Na, Mg, Al, K, Ca, Zn, Mn, Ba; sub-major elements (10 ng/m3 < mass level < 100 ng/m3) including Li, Cr, Ni,Cu, Ga, Sr, Pb; and minor elements (mass level < 10 ng/m3), Be, V, As, Se, Rb, Ag, Cd, Tl, Bi. The mass levels of

  11. [Characteristics of Water-Soluble Inorganic Ions in PM2.5 Emitted from Coal-Fired Power Plants].

    PubMed

    Ma, Zi-zhen; Li, Zhen; Jiang, Jing-kun; Ye, Zhi-xiang; Deng, Jian-guo; Duan, Lei

    2015-07-01

    To characterize the primary PM2.5 emission from coal-fired power plants in China, and to quantitatively evaluate the effects of flue gas denitrification and desulfurization on PM2.5 emission, a pulverized coal fired (PC) power plant and a circulating fluidized bed (CFB) plant were selected for measuring the mass concentration and water-soluble ion composition of PM2.5 in flue gas. The results showed that the mass concentration of PM2.5 generated from the CFB was much higher than that from the PC, while the mass concentrations of PM2.5 emitted from these two plants were very similar, because the CFB was equipped with an electrostatic-bag precipitator (EBP) with higher PM2.5 removal efficiency than the common electrostatic precipitator (ESP). Although the total concentration of water-soluble ions in PM2.5 generated from the PC was lower than that from the CFB, the total concentration of water-soluble ions in PM2.5 emitted from the PC was much higher than that from the CFB, which implied that PM2.5 emission from the PC was greatly affected by the flue gas treatment installations. For example, the flue gas denitrification system produced H2SO4 mist, part of which reacted with the excessive NH3 in the flue gas to form NH4HSO4 in PM2.5 and to increase the acidity of PM2.5. In addition, the escaping of desulfurization solution during the flue gas desulfurization process could also introduce NH4+ and SO2- into PM2.5. Therefore, although the main water-soluble ions in PM2.5 generated from both of the plants were Ca2+ and SO(4)2-, the major cation was changed to NH4+ when emitted from PC. PMID:26489299

  12. [Characteristics of Water-Soluble Inorganic Ions in PM2.5 Emitted from Coal-Fired Power Plants].

    PubMed

    Ma, Zi-zhen; Li, Zhen; Jiang, Jing-kun; Ye, Zhi-xiang; Deng, Jian-guo; Duan, Lei

    2015-07-01

    To characterize the primary PM2.5 emission from coal-fired power plants in China, and to quantitatively evaluate the effects of flue gas denitrification and desulfurization on PM2.5 emission, a pulverized coal fired (PC) power plant and a circulating fluidized bed (CFB) plant were selected for measuring the mass concentration and water-soluble ion composition of PM2.5 in flue gas. The results showed that the mass concentration of PM2.5 generated from the CFB was much higher than that from the PC, while the mass concentrations of PM2.5 emitted from these two plants were very similar, because the CFB was equipped with an electrostatic-bag precipitator (EBP) with higher PM2.5 removal efficiency than the common electrostatic precipitator (ESP). Although the total concentration of water-soluble ions in PM2.5 generated from the PC was lower than that from the CFB, the total concentration of water-soluble ions in PM2.5 emitted from the PC was much higher than that from the CFB, which implied that PM2.5 emission from the PC was greatly affected by the flue gas treatment installations. For example, the flue gas denitrification system produced H2SO4 mist, part of which reacted with the excessive NH3 in the flue gas to form NH4HSO4 in PM2.5 and to increase the acidity of PM2.5. In addition, the escaping of desulfurization solution during the flue gas desulfurization process could also introduce NH4+ and SO2- into PM2.5. Therefore, although the main water-soluble ions in PM2.5 generated from both of the plants were Ca2+ and SO(4)2-, the major cation was changed to NH4+ when emitted from PC.

  13. Progress integrating ID-TIMS U-Pb geochronology with accessory mineral geochemistry: towards better accuracy and higher precision time

    NASA Astrophysics Data System (ADS)

    Schoene, B.; Samperton, K. M.; Crowley, J. L.; Cottle, J. M.

    2012-12-01

    It is increasingly common that hand samples of plutonic and volcanic rocks contain zircon with dates that span between zero and >100 ka. This recognition comes from the increased application of U-series geochronology on young volcanic rocks and the increased precision to better than 0.1% on single zircons by the U-Pb ID-TIMS method. It has thus become more difficult to interpret such complicated datasets in terms of ashbed eruption or magma emplacement, which are critical constraints for geochronologic applications ranging from biotic evolution and the stratigraphic record to magmatic and metamorphic processes in orogenic belts. It is important, therefore, to develop methods that aid in interpreting which minerals, if any, date the targeted process. One promising tactic is to better integrate accessory mineral geochemistry with high-precision ID-TIMS U-Pb geochronology. These dual constraints can 1) identify cogenetic populations of minerals, and 2) record magmatic or metamorphic fluid evolution through time. Goal (1) has been widely sought with in situ geochronology and geochemical analysis but is limited by low-precision dates. Recent work has attempted to bridge this gap by retrieving the typically discarded elution from ion exchange chemistry that precedes ID-TIMS U-Pb geochronology and analyzing it by ICP-MS (U-Pb TIMS-TEA). The result integrates geochemistry and high-precision geochronology from the exact same volume of material. The limitation of this method is the relatively coarse spatial resolution compared to in situ techniques, and thus averages potentially complicated trace element profiles through single minerals or mineral fragments. In continued work, we test the effect of this on zircon by beginning with CL imaging to reveal internal zonation and growth histories. This is followed by in situ LA-ICPMS trace element transects of imaged grains to reveal internal geochemical zonation. The same grains are then removed from grain-mount, fragmented, and

  14. Performance and applicability of a 2.5-D ice-flow model in the vicinity of a dome

    NASA Astrophysics Data System (ADS)

    Passalacqua, Olivier; Gagliardini, Olivier; Parrenin, Frédéric; Todd, Joe; Gillet-Chaulet, Fabien; Ritz, Catherine

    2016-07-01

    Three-dimensional ice flow modelling requires a large number of computing resources and observation data, such that 2-D simulations are often preferable. However, when there is significant lateral divergence, this must be accounted for (2.5-D models), and a flow tube is considered (volume between two horizontal flowlines). In the absence of velocity observations, this flow tube can be derived assuming that the flowlines follow the steepest slope of the surface, under a few flow assumptions. This method typically consists of scanning a digital elevation model (DEM) with a moving window and computing the curvature at the centre of this window. The ability of the 2.5-D models to account properly for a 3-D state of strain and stress has not clearly been established, nor their sensitivity to the size of the scanning window and to the geometry of the ice surface, for example in the cases of sharp ridges. Here, we study the applicability of a 2.5-D ice flow model around a dome, typical of the East Antarctic plateau conditions. A twin experiment is carried out, comparing 3-D and 2.5-D computed velocities, on three dome geometries, for several scanning windows and thermal conditions. The chosen scanning window used to evaluate the ice surface curvature should be comparable to the typical radius of this curvature. For isothermal ice, the error made by the 2.5-D model is in the range 0-10 % for weakly diverging flows, but is 2 or 3 times higher for highly diverging flows and could lead to a non-physical ice surface at the dome. For non-isothermal ice, assuming a linear temperature profile, the presence of a sharp ridge makes the 2.5-D velocity field unrealistic. In such cases, the basal ice is warmer and more easily laterally strained than the upper one, the walls of the flow tube are not vertical, and the assumptions of the 2.5-D model are no longer valid.

  15. 41 CFR 51-2.5 - Committee decision.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Contracts COMMITTEE FOR PURCHASE FROM PEOPLE WHO ARE BLIND OR SEVERELY DISABLED 2-COMMITTEE FOR PURCHASE FROM PEOPLE WHO ARE BLIND OR SEVERELY DISABLED § 51-2.5 Committee decision. The Committee considers...

  16. 41 CFR 51-2.5 - Committee decision.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Contracts COMMITTEE FOR PURCHASE FROM PEOPLE WHO ARE BLIND OR SEVERELY DISABLED 2-COMMITTEE FOR PURCHASE FROM PEOPLE WHO ARE BLIND OR SEVERELY DISABLED § 51-2.5 Committee decision. The Committee considers...

  17. General 2.5 power law of metallic glasses.

    PubMed

    Zeng, Qiaoshi; Lin, Yu; Liu, Yijin; Zeng, Zhidan; Shi, Crystal Y; Zhang, Bo; Lou, Hongbo; Sinogeikin, Stanislav V; Kono, Yoshio; Kenney-Benson, Curtis; Park, Changyong; Yang, Wenge; Wang, Weihua; Sheng, Hongwei; Mao, Ho-Kwang; Mao, Wendy L

    2016-02-16

    Metallic glass (MG) is an important new category of materials, but very few rigorous laws are currently known for defining its "disordered" structure. Recently we found that under compression, the volume (V) of an MG changes precisely to the 2.5 power of its principal diffraction peak position (1/q1). In the present study, we find that this 2.5 power law holds even through the first-order polyamorphic transition of a Ce68Al10Cu20Co2 MG. This transition is, in effect, the equivalent of a continuous "composition" change of 4f-localized "big Ce" to 4f-itinerant "small Ce," indicating the 2.5 power law is general for tuning with composition. The exactness and universality imply that the 2.5 power law may be a general rule defining the structure of MGs. PMID:26831105

  18. General 2.5 power law of metallic glasses

    PubMed Central

    Zeng, Qiaoshi; Lin, Yu; Liu, Yijin; Zeng, Zhidan; Shi, Crystal Y.; Zhang, Bo; Lou, Hongbo; Sinogeikin, Stanislav V.; Kono, Yoshio; Kenney-Benson, Curtis; Park, Changyong; Yang, Wenge; Wang, Weihua; Sheng, Hongwei; Mao, Ho-kwang; Mao, Wendy L.

    2016-01-01

    Metallic glass (MG) is an important new category of materials, but very few rigorous laws are currently known for defining its “disordered” structure. Recently we found that under compression, the volume (V) of an MG changes precisely to the 2.5 power of its principal diffraction peak position (1/q1). In the present study, we find that this 2.5 power law holds even through the first-order polyamorphic transition of a Ce68Al10Cu20Co2 MG. This transition is, in effect, the equivalent of a continuous “composition” change of 4f-localized “big Ce” to 4f-itinerant “small Ce,” indicating the 2.5 power law is general for tuning with composition. The exactness and universality imply that the 2.5 power law may be a general rule defining the structure of MGs. PMID:26831105

  19. Stereochemistry of 2',5' nucleic acids and their constituents.

    PubMed

    Premraj, B J; Yathindra, N

    1998-10-01

    Shape and dimension of the preferred nucleotide repeats in nucleic acids are found to depend on whether the sugar-phosphate linkage is of 2',5' or 3',5' type. It is shown that a nucleotide which is "compact" in 3',5' nucleic acids is rendered "extended" and vice versa for a given sugar pucker. It is interesting that this feature is accompanied by a switch in the preferred sugar ring conformation in 3',5' and 2',5' nucleic acids. 3' ribose and 3' deoxyribose rings (in 2',5' linkages) tend to favour C2' endo and C3' endo puckers respectively in contrast to C3' endo and C2' endo puckers favored by 2' ribose and 2' deoxyribose sugars (in 3',5' linkages). The distinguishable features between the nucleotide repeats of 3',5' and 2',5' nucleic acids need to be recognised while discussing their structural properties, as well as those of a variety of complexes that could be formed involving 2',5' and 3',5' strands of DNA and RNA. Ability and stability, or lack of them, for formation of a specific combination of these complexes may be directly related to the stereochemical constraints imposed as a consequence of conformationally homogeneous or heterogeneous nature of the repeating nucleotides of the complexing chains. As a first step towards delineating stereochemical features that distinguish 2',5' nucleic acids from their naturally occurring isomer A and B type helices have been modelled using the new concept of "compact" and "extended" nucleotide repeat that seemingly unifies helix generation of both types of linkages. Helical models for 2',5' RNA with "dinucleotide" repeat based on the crystal structure of 2',5' ApU have also been obtained.

  20. Wise Moves in Hard Times: Creating & Managing Resilient Colleges & Universities. The Jossey-Bass Higher and Adult Education Series. First Edition.

    ERIC Educational Resources Information Center

    Leslie, David W.; Fretwell, E. K., Jr.

    Based on data gathered on-site at 13 colleges and universities, this volume offers an in-depth analysis of how colleges and universities have been affected by hard times, how they have risen to the challenges, and what their responses mean to the public and its support for higher education. Part 1 describes the study itself in detail and reports…

  1. Building on Strengths in a Time of Retrenchment: Developing an M.Ed. in Higher Education--Student Affairs Emphasis to Train Christian Practitioners

    ERIC Educational Resources Information Center

    Morris, Jason; Haseltine, Jeffrey; Williams, Carol

    2007-01-01

    To gain approval of a new master's degree in difficult financial times, the authors applied strategies that are applicable at other institutions. Using existing internal resources to build on the university's mission was key in developing a new M.Ed. in Higher Education--Student Affairs Emphasis at Abilene Christian University. Creativity and…

  2. Late time acceleration of the 3-space in a higher dimensional steady state universe in dilaton gravity

    SciTech Connect

    Akarsu, Özgür; Dereli, Tekin E-mail: tdereli@ku.edu.tr

    2013-02-01

    We present cosmological solutions for (1+3+n)-dimensional steady state universe in dilaton gravity with an arbitrary dilaton coupling constant w and exponential dilaton self-interaction potentials in the string frame. We focus particularly on the class in which the 3-space expands with a time varying deceleration parameter. We discuss the number of the internal dimensions and the value of the dilaton coupling constant to determine the cases that are consistent with the observed universe and the primordial nucleosynthesis. The 3-space starts with a decelerated expansion rate and evolves into accelerated expansion phase subject to the values of w and n, but ends with a Big Rip in all cases. We discuss the cosmological evolution in further detail for the cases w = 1 and w = ½ that permit exact solutions. We also comment on how the universe would be conceived by an observer in four dimensions who is unaware of the internal dimensions and thinks that the conventional general relativity is valid at cosmological scales.

  3. Speaking rate, voice-onset time, and quantity: the search for higher-order invariants for two Icelandic speech cues.

    PubMed

    Pind, J

    1995-04-01

    The temporal structure of speech has been shown to be highly variable. Speaking rate, stress, and other factors influence the duration of individual speech sounds. The highly elastic nature of speech would seem to pose a problem for the listener, especially with respect to the perception of temporal speech cues such as voice-onset time (VOT) and quantity: How does the listener disentangle those temporal changes which are linguistically significant from those which are extrinsic to the linguistic message? This paper reports data on the behavior of two Icelandic speech cues at different speaking rates. The results show that manipulations of rate have the effect of slightly blurring the distinction between unaspirated and aspirated stops. Despite great changes in the absolute durations of vowels and consonants, the two categories of syllables--V:C and VC:--are nonetheless kept totally distinct. In two perceptual experiments, it is shown that while the ratio of vowel to rhyme duration is the primary cue to quantity and remains invariant at different rates, no such ratio can be defined for VOT. These results imply that quantity is the only one of these two speech cues that is self-normalizing for rate. Models of rate-dependent speech processing need to address this difference.

  4. Quantifying PM2.5-meteorology sensitivities in a global climate model

    NASA Astrophysics Data System (ADS)

    Westervelt, D. M.; Horowitz, L. W.; Naik, V.; Tai, A. P. K.; Fiore, A. M.; Mauzerall, D. L.

    2016-10-01

    Climate change can influence fine particulate matter concentrations (PM2.5) through changes in air pollution meteorology. Knowledge of the extent to which climate change can exacerbate or alleviate air pollution in the future is needed for robust climate and air pollution policy decision-making. To examine the influence of climate on PM2.5, we use the Geophysical Fluid Dynamics Laboratory Coupled Model version 3 (GFDL CM3), a fully-coupled chemistry-climate model, combined with future emissions and concentrations provided by the four Representative Concentration Pathways (RCPs). For each of the RCPs, we conduct future simulations in which emissions of aerosols and their precursors are held at 2005 levels while other climate forcing agents evolve in time, such that only climate (and thus meteorology) can influence PM2.5 surface concentrations. We find a small increase in global, annual mean PM2.5 of about 0.21 μg m-3 (5%) for RCP8.5, a scenario with maximum warming. Changes in global mean PM2.5 are at a maximum in the fall and are mainly controlled by sulfate followed by organic aerosol with minimal influence of black carbon. RCP2.6 is the only scenario that projects a decrease in global PM2.5 with future climate changes, albeit only by -0.06 μg m-3 (1.5%) by the end of the 21st century. Regional and local changes in PM2.5 are larger, reaching upwards of 2 μg m-3 for polluted (eastern China) and dusty (western Africa) locations on an annually averaged basis in RCP8.5. Using multiple linear regression, we find that future PM2.5 concentrations are most sensitive to local temperature, followed by surface wind and precipitation. PM2.5 concentrations are robustly positively associated with temperature, while negatively related with precipitation and wind speed. Present-day (2006-2015) modeled sensitivities of PM2.5 to meteorological variables are evaluated against observations and found to agree reasonably well with observed sensitivities (within 10-50% over the

  5. Affinity labeling of (2'-5')-oligoadenylate-activated endonuclease with (/sup 32/P)-2', 5'A and its analogs

    SciTech Connect

    Saarma, M.Y.; Gordon, J.; Minks, M.A.

    1985-09-01

    This paper examines the role interferons play in the origin of the antiviral state of cells and in the inhibition of virus reproduction. Treatment of cells with interferon induces the synthesis of a whole series of proteins. For affinity labeling of 2', 5'A-dependent endoribonuclease, the authors synthesized P-32 labeled 2; 5'A by two methods. Results of the investigation show that the most probable candidate for 2', 5'A-dependent endoribonuclease is the protein with molecular weight 80,000. The role of the other two proteins is still unknown.

  6. Year-long continuous personal exposure to PM 2.5 recorded by a fast responding portable nephelometer

    NASA Astrophysics Data System (ADS)

    Braniš, Martin; Kolomazníková, Jana

    2010-08-01

    Personal exposure to particulate matter of aerodynamic diameter under 2.5 μm (PM 2.5) was monitored using a DustTrak nephelometer. The battery-operated unit, worn by an adult individual for a period of approximately one year, logged integrated average PM 2.5 concentrations over 5 min intervals. A detailed time-activity diary was used to record the experimental subject's movement and the microenvironments visited. Altogether 239 days covering all the months (except April) were available for the analysis. In total, 60 463 acceptable 5-min averages were obtained. The dataset was divided into 7 indoor and 4 outdoor microenvironments. Of the total time, 84% was spent indoors, 10.9% outdoors and 5.1% in transport. The indoor 5-min PM 2.5 average was higher (55.7 μg m -3) than the outdoor value (49.8 μg m -3). The highest 5-min PM 2.5 average concentration was detected in restaurant microenvironments (1103 μg m -3), the second highest 5-min average concentration was recorded in indoor spaces heated by stoves burning solid fuels (420 μg m -3). The lowest 5-min mean aerosol concentrations were detected outdoors in rural/natural environments (25 μg m -3) and indoors at the monitored person's home (36 μg m -3). Outdoor and indoor concentrations of PM 2.5 measured by the nephelometer at home and during movement in the vicinity of the experimental subject's home were compared with those of the nearest fixed-site monitor of the national air quality monitoring network. The high correlation coefficient (0.78) between the personal and fixed-site monitor aerosol concentrations suggested that fixed-site monitor data can be used as proxies for personal exposure in residential and some other microenvironments. Collocated measurements with a reference method (β-attenuation) showed a non-linear systematic bias of the light-scattering method, limiting the use of direct concentration readings for exact exposure analysis.

  7. Personal exposures to PM 2.5 and their relationships with microenvironmental concentrations

    NASA Astrophysics Data System (ADS)

    Lim, Soogil; Kim, Jeonghoon; Kim, Taehyun; Lee, Kiyoung; Yang, Wonho; Jun, Sangil; Yu, Seungdo

    2012-02-01

    Personal exposure to particulate matter of aerodynamic diameters less than 2.5 μm (PM 2.5) can be affected by various factors. The purpose of this study was to determine the impact of activity pattern and the contribution of each microenvironment to personal PM 2.5 exposure. Technicians carried a nephelometer for PM 2.5 while engaging in scripted time location activities. The scripted activities of 10 different population groups were based on time activity patterns of the Seoul population in Korea. A total of 58 daily PM 2.5 personal exposures were available for analysis. The average PM 2.5 personal exposure was 19.8 ± 15.3 μg m -3. The average personal exposure of each population group ranged from 9.8 to 43.1 μg m -3. High peak and average concentrations were observed in restaurants and bars; such high concentrations were due to secondhand smoke and cooking with charcoal on tables. The residential indoor level of the nine microenvironments was the largest contributor to personal exposure. The contributions from residential indoor, non-residential indoor, transportation, and outdoor levels were 36.2%, 53.4%, 6.7%, and 3.7%, respectively. The contributions of microenvironments varied among population groups; these variations suggest that the impact of activity pattern on personal exposure is significant.

  8. Spatial and Temporal Distribution of PM2.5 Pollution in Xi’an City, China

    PubMed Central

    Huang, Ping; Zhang, Jingyuan; Tang, Yuxiang; Liu, Lu

    2015-01-01

    The monitoring data of the 13 stations in Xi’an city for the whole years of 2013 and 2014 was counted and analyzed. Obtaining the spatial and temporal distribution characteristics of PM2.5 was the goal. Cluster analysis and the wavelet transform were utilized to discuss the regional distribution characteristics of PM2.5 concentration (ρ(PM2.5)) and the main features of its yearly changes and sudden changes. Additionally, some relevant factors were taken into account to interpret the changes. The results show that ρ(PM2.5) in Xi’an during 2013 was generally higher than in 2014, it is high in winter and low in summer, and the high PM2.5 concentration centers are around the People’s Stadium and Caotan monitoring sites; For the regional PM2.5 distribution, the 13 sites can be divided into three categories, in which Textile city is Cluster 1, and High-tech Western is Cluster 2, and Cluster 3 includes the remaining 11 monitoring sites; the coefficient of goodness of the cluster analysis is 0.6761, which indicates that the result is acceptable. As for the yearly change, apart from June and July, the average ρ(PM2.5) concentration has been above the normal concentration criteria of Chinese National Standard (50 g/m3); cloudy weather and low winds are the major meteorological factors leading to the sudden changes of ρ(PM2.5). PMID:26068090

  9. A New n = 4 Layered Ruddlesden-Popper Phase K(2.5)Bi(2.5)Ti4O13 Showing Stoichiometric Hydration.

    PubMed

    Liu, Samuel; Avdeev, Maxim; Liu, Yun; Johnson, Mark R; Ling, Chris D

    2016-02-15

    A new bismuth-containing layered perovskite of the Ruddlesden-Popper type, K(2.5)Bi(2.5)Ti4O13, has been prepared by solid-state synthesis. It has been shown to hydrate to form stoichiometric K(2.5)Bi(2.5)Ti4O13·H2O. Diffraction data show that the structure consists of a quadruple-stacked (n = 4) perovskite layer, with potassium ions occupying the rock salt layer and its next-nearest A site. The hydrated sample was shown to remove the offset between stacked perovskite layers relative to the dehydrated sample. Computational methods show that the hydrated phase consists of intact H2O molecules in a vertical "pillared" arrangement bridging across the interlayer space. Rotations of H2O molecules about the c axis were evident in molecular dynamic calculations, which increased in rotation angle with increasing temperature. In situ diffraction data for the dehydrated phase point to a broad structural phase transition from orthorhombic to tetragonal at ∼600 °C. The relative bismuth-rich composition in the perovskite block results in a higher transition temperature compared to related perovskite structures. Water makes a significant contribution to the dielectric constant, which disappears after dehydration.

  10. Residential indoor PM 10 and PM 2.5 in Hong Kong and the elemental composition

    NASA Astrophysics Data System (ADS)

    Chao, Christopher Y.; Wong, Kelvin K.

    Indoor air particulate samples were collected in 34 homes and their adjacent outdoor environments in Hong Kong during the fall and winter seasons. It was found that the mean indoor PM 2.5 and PM 10 concentrations were 45.0 and 63.3 μg m -3, respectively. The corresponding mean outdoor levels were 47.0 and 69.5 μg m -3, respectively. The indoor particulate levels were found to be about 2-4 times higher than those in the homes in western countries where most are located in suburb areas with a much better ambient air quality. Pearson paired t-tests were conducted on the data and it was found that poor correlation was seen in the indoor and the outdoor particulate concentrations. This was probably due to the fact that windows were closed more often in the fall and winter seasons keeping the ventilation rate low, plus the factor that window type air conditioners were used commonly in Hong Kong, which again, constituted to a low air change rate. Both the indoor and the outdoor elemental compositions of the particulate samples collected in these 34 homes were identified by proton-induced X-ray emission analysis. Seventeen elements were identified. The mean inorganic elemental compositions in the indoor PM 2.5 and PM 10 samples were 6.4 and 10.2 μg m -3, respectively while those in the outdoor samples were 7.9 and 14.1 μg m -3, respectively. Enrichment factor analysis was performed and it was noted that those species existing in fine mode were highly enriched (bromine, lead, nickel, potassium, sulfur, vanadium and zinc) while those species existing in the coarse mode had their enrichment factors close to 1 (aluminum, calcium, iron, magnesium, silicon, sodium and titanium).

  11. Analysis of Personal and Home Characteristics Associated with the Elemental Composition of PM2.5 in Indoor, Outdoor, and Personal Air in the RIOPA Study.

    PubMed

    Ryan, Patrick H; Brokamp, Cole; Fan, Zhi-Hua; Rao, M B

    2015-12-01

    , outdoor, and personal PM2.5 varied significantly across sample types within each study site and also across study sites within each sample type. Using model-based clustering, we identified seven clusters of RIOPA participants whose personal PM2.5 samples had similar patterns of elemental composition. Using this approach, subsets of RIOPA participants were identified whose personal exposures to PM2.5 (and its elements) were significantly higher than their indoor and outdoor concentrations (and vice versa). The results of linear and random forest regression models were consistent with our correlation analyses and demonstrated that (1) indoor concentrations were more significantly associated with personal exposure than were outdoor concentrations and (2) participant reports of time spent at their home significantly modified many of the associations between indoor and personal concentrations. In linear regression models, the inclusion of indoor concentrations significantly improved the prediction of personal exposures to Ba, Ca, Cl, Cu, K, Sn, Sr, V, and Zn compared with the use of outdoor elemental concentrations alone. Including additional information on personal and home characteristics improved the prediction for only one element, Pb. Our results support the use of outdoor monitoring sites as surrogates of personal exposure for a limited number of individual elements associated with long-range transport and with a few local or indoor sources. Based on our PCA and clustering analyses, we concluded that the overall elemental composition of PM2.5 obtained at outdoor monitoring sites may not accurately represent the elemental composition of personal PM2.5. Although the data used in these analyses compared outdoor PM2.5 composition collected at the home with indoor and personal samples, our results imply that studies examining the complete elemental composition of PM2.5 should be cautious about using data from central outdoor monitoring sites because of the potential for

  12. Personal PM2.5 and indoor CO in nomadic tents using open and chimney biomass stoves on the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Li, Chaoliu; Kang, Shichang; Chen, Pengfei; Zhang, Qianggong; Guo, Junming; Mi, Jue; Basang, Puchi; Luosang, Quzhen; Smith, Kirk R.

    2012-11-01

    Yak dung is the primary source of energy for cooking and heating of nomadic Tibetan herders. Personal PM2.5 and indoor CO concentrations and time-activity patterns were investigated in nomadic tents with open stoves and locally available chimney stoves. Personal PM2.5 monitoring using a light-scattering datalogger was performed with women in five tents with open fires and four with chimney stoves over 3 days. Meanwhile, indoor CO variation was also measured. Results showed that 24 h average concentrations of PM2.5 and CO in the tents with open stoves were 1.42 mg m-3 (n = 5, SD = 3.26) and 6.69 mg m-3 (n = 4; SD = 9.11), respectively, which were significantly higher than the tents with chimney stoves having 0.14 mg m-3 (n = 4; SD = 0.65) and 0.12 mg m-3 (n = 4; SD = 1.01) of PM2.5 and CO, respectively. Although chimney stoves significantly reduced indoor air pollution, the concentration of PM2.5 was still higher than annual WHO Air Quality Guideline (0.035 mg m-3). Diurnal variability of PM2.5 and CO was similar and had multiple peaks. This phenomenon was closely connected with behaviors of the participants within the tents. Average 1-h peak concentrations of PM2.5 and CO exceed 24-h mean values by a factor of 5.0 and 4.3, respectively. Significant correlation between hourly PM2.5 and CO concentrations was revealed. Generally, women and children spent 7 h longer than other family members within the tent each day and were thus exposed to higher levels of pollutants. Secondhand tobacco smoke and burning of yak oil lamps are also present in many households, but are much smaller contributors to the exposures. Therefore, yak dung combustion contributes substantially to the personal exposure of householders in this setting even during the warmest time of year in this setting and that although exposures are greatly reduced with chimney stoves; they are still high by comparison to national standards or WHO guidelines.

  13. Determination of 2,5-toluylenediamine (2,5-TDA) and aromatic amines in urine after personal application of hair dyes: kinetics and doses.

    PubMed

    Schettgen, Thomas; Heinrich, K; Kraus, T; Gube, Monika

    2011-02-01

    The personal use of hair dye products is currently under discussion due to the potentially increased risk of bladder cancer among long-time users described in epidemiological literature. In order to investigate the dermal absorption of aromatic diamines as well as aromatic amines possibly present as contaminants in hair dye formulations, we conducted a biomonitoring study under real-life conditions and calculated kinetics and doses for the urinary excretion. Urine samples of two female subjects were collected for a time period of 48 h after personal application of a hair dye cream and analysed for aromatic diamines as well as o-toluidine and 4-aminobiphenyl using highly specific GC/MS-methods. 2,5-Toluylenediamine (2,5-TDA) as active ingredient of hair dyes is rapidly absorbed dermally. After a distribution phase of 12 h, 2,5-TDA is excreted with a half-time of 8 h. Excretion was 90% complete within 24 h after application. The doses of 2,5-TDA excreted within 48 h were 700 μg for application of a brown-reddish hair dye cream and 1.5 mg for the application of a brown-black hair dye cream. Urinary 4-aminobiphenyl as well as contaminations with other aromatic diamines were not detectable in our study. Due to the artifactual formation of o-toluidine in the presence of high concentrations of urinary 2,5-TDA, our results could not prove an increased internal exposure of humans to carcinogenic amines after personal application of hair dyes.

  14. BLOCKAGE 2.5 user`s manual

    SciTech Connect

    Rao, D.V.; Brideau, J.; Shaffer, C.; Souto, F.; Bernahl, W.

    1996-12-01

    The BLOCKAGE 2.5 code described in this User`s Manual was developed by the US Nuclear Regulatory Commission (NRC) as a tool to evaluate licensee compliance with NRC Bulletin 96-03, ``Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling Water Reactors.`` As such, BLOCKAGE 2.5 provides a generalized framework into which a user can input plant-specific and insulation-specific data for performing analyses in accordance with Regulatory Guide 1.82, Rev. 2. This user`s manual describes the capabilities of BLOCKAGE 2.5 along with a description of the graphics user`s interface provided for data entry. Each input/output dialog is described in detail along with special considerations related to developing and executing BLOCKAGE. Also, several sample problems are provided such that user can easily modify them to suit a particular plant of interest. The models used in BLOCKAGE 2.5 and their validation are presented in the accompanying NUREG/CR-6371. The BLOCKAGE models were designed to be parametric in nature, allowing the user flexibility to examine the impact of several modeling assumptions and to conduct sensitivity analyses. As a result, BLOCKAGE 2.5 results are known to be very sensitive to the user provided input. It is therefore strongly recommended that users become thoroughly familiar with BLOCKAGE models and their limitations as described in NUREG/CR-6224.

  15. Seasonal trends in PM2.5 source contributions in Beijing, China

    NASA Astrophysics Data System (ADS)

    Zheng, Mei; Salmon, Lynn G.; Schauer, James J.; Zeng, Limin; Kiang, C. S.; Zhang, Yuanhang; Cass, Glen R.

    The 24-h PM2.5 samples (particles with an aerodynamic diameter of 2.5 μm or less) were taken at 6-day intervals at five urban and rural sites simultaneously in Beijing, China for 1 month in each quarter of calendar year 2000. Samples at each site were combined into a monthly composite for the organic tracer analysis by GC/MS (gas chromatography/mass spectrometry). Compared to the data obtained from other metropolitan cities in the US, the PM2.5 mass and fine organic carbon (OC) concentrations in Beijing were much higher with an annual average of 101 and 20.9 μg m -3, respectively. Over one hundred organic compounds including unique tracers for important sources were quantified in PM2.5 in Beijing. Source apportionment of fine OC was conducted using chemical mass balance receptor model (CMB) in combination with particle-phase organic compounds as fitting tracers. Carbonaceous aerosols and major ions (sulfate, nitrate and ammonium) constituted 69% of PM2.5 mass on average. The major sources of PM2.5 mass in Beijing averaged over five sites on an annual basis were determined as dust (20%), secondary sulfate (17%), secondary nitrate (10%), coal combustion (7%), diesel and gasoline exhaust (7%), secondary ammonium (6%), biomass aerosol (6%), cigarette smoke (1%), and vegetative detritus (1%). The lowest PM2.5 mass concentration was found in January (60.9 μg m -3), but the contribution of carbonaceous aerosol to PM2.5 mass was maximal during this season, accounting for 57% of the mass. During cold heating season, the contributions from coal combustion and biomass aerosol to PM2.5 mass increased, accounting for 20.9% of fine particle mass in October and 24.5% in January. The contribution of the biomass aerosols peaked in the fall. In April 2000, the impact of dust storms was so significant that dust alone constituted 36% of PM2.5 mass. On average, the model resolved 88% of the sources of the PM2.5 mass concentrations in Beijing.

  16. [Characteristics of organic carbon and elemental carbon in PM2.5 in Shuozhou City].

    PubMed

    Liu, Feng-xian; Peng, Lin; Bai, Hui-ling; Mu, Ling; Liu, Xiao-feng; Li, Li-juan; Liu, Xin

    2015-03-01

    PM2.5 samples were collected at four sampling sites in Shuozhou during the heating and non-heating periods. Organic carbon (OC) and elemental carbon (EC) in PM2.5 were analyzed by Elementar Analysensysteme GmbH vario EL cube and the concentration, spatial and temporal distribution characteristics and main sources of OC and EC were studied. The results were as following: average concentrations of OC and EC in PM2.5 during non-heating period were (14.3 ± 2.7) μg x m(-3) and (10.3 ± 3.1) μg x m(-3) while (23.3 ± 5.9) μg xm(-3) and (20.0 ± 5.7) μg x m(-3) during heating period. The concentrations of OC and EC at four sites during the heating period were higher than those during the non-heating period. The concentrations of OC and EC at SW site during heating were the highest which were 28.5 μg x m(-3) and 28.1 μg x m(-3) while the concentrations at PS sites during non-heating period were the highest, which were 17.7 μg x m(-3) and 14.1 μg x m(-3). The ratios between OC and EC during the heating and non-heating period were all below 2 and the correlation between OC and EC was not good with R2 of 0. 66 during heating period and 0.52 during non-heating period which indicated that sources of carbon aerosols were complex. Carbonaceous aerosol pollution should be reduced by controlling the primary emissions such as coal combustion, vehicle exhaust and biomass burning, and by paying attention to secondary pollution at the same time to improve the air quality in Shuozhou City. The concentrations of SOC during heating and non-heating period were (6.44 ± 2.77) μg x m(-3) and (4.11 ± 1.92) μg x m(-3). PMID:25929042

  17. PM 2.5 and PM 10: The influence of sugarcane burning on potential cancer risk

    NASA Astrophysics Data System (ADS)

    Silva, Flavio S.; Cristale, Joyce; André, Paulo A.; Saldiva, Paulo H. N.; Marchi, Mary R. R.

    2010-12-01

    In Brazil, sugarcane fields are often burned to facilitate manual harvesting, and this burning causes environmental pollution from the large amounts of soot released into the atmosphere. This material contains numerous organic compounds such as PAHs. In this study, the concentrations of PAHs in two particulate-matter fractions (PM 2.5 and PM 10) in the city of Araraquara (SE Brazil, with around 200,000 inhabitants and surrounded by sugarcane plantations) were determined during the sugarcane harvest (HV) and non-harvest (NHV) seasons in 2008 and 2009. The sampling strategy included four campaigns, with 60 samples in the NHV season and 220 samples in the HV season. The PM 2.5 and PM 10 fractions were collected using a dichotomous sampler (10 L min -1, 24 h) with Teflon™ filters. The filter sets were extracted (ultrasonic bath with hexane/acetone (1:1 v/v)) and analyzed by HPLC/Fluorescence. The median concentration for total PAHs (PM 2.5 in 2009) was 0.99 ng m -3 (NHV) and 3.3 ng m -3 (HV). In the HV season, the total concentration of carcinogenic PAHs (benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, and benzo(a)pyrene) was 5 times higher than in the NHV season. B(a)P median concentrations were 0.017 ng m -3 and 0.12 ng m -3 for the NHV and HV seasons, respectively. The potential cancer risk associated with exposure through inhalation of these compounds was estimated based on the benzo[a]pyrene toxic equivalence (BaP eq), where the overall toxicity of a PAH mixture is defined by the concentration of each compound multiplied by its relative toxic equivalence factor (TEF). BaP eq median (2008 and 2009 years) ranged between 0.65 and 1.0 ng m -3 and 1.2-1.4 ng m -3 for the NHV and HV seasons, respectively. Considering that the maximum permissible BaP eq in ambient air is 1 ng m -3, related to the increased carcinogenic risk, our data suggest that the level of human exposure to PAHs in cities surrounded by sugarcane crops where the burning process is used

  18. AMBIENT PM2.5 SAMPLING AND ANALYSIS

    SciTech Connect

    Unknown

    2001-10-31

    This interim report summarizes detailed findings and conclusions drawn from evaluations of data obtained from the operation of ambient PM{sub 2.5} speciation sites in a geographical area encompassing southeastern Ohio, western Pennsylvania and northwestern West Virginia. The overall goal of this program, called the Upper Ohio River Valley Project (UORVP), is to better understand the relationship between coal-based power system emissions and ambient air quality in the Upper Ohio River Valley region through the collection of chemically resolved or speciated data. A summary of the sampling activities, sample analyses and the correlation and interpretation of data acquired from February 1999 through March of 2001 are reported. Mass and speciated data from urban and rural sources are compared and seasonal variations in PM{sub 2.5} distribution are also examined. Correlations between meteorological parameters and total PM{sub 2.5} mass are also presented.

  19. AMBIENT PM2.5 SAMPLING AND ANALYSIS

    SciTech Connect

    Unknown

    2002-10-31

    This interim report summarizes detailed findings and conclusions drawn from evaluations of data obtained from the operation of ambient PM{sub 2.5} speciation sites in a geographical area encompassing southeastern Ohio, western Pennsylvania and northwestern West Virginia. The overall goal of this program, called the Upper Ohio River Valley Project (UORVP), is to better understand the relationship between coal-based power system emissions and ambient air quality in the Upper Ohio River Valley region through the collection of chemically resolved or speciated data. A summary of the sampling activities, sample analyses and the correlation and interpretation of data acquired from February 1999 through March of 2001 are reported. Mass and speciated data from urban and rural sources are compared and seasonal variations in PM{sub 2.5} distribution are also examined. Correlations between meteorological parameters and total PM{sub 2.5} mass are also presented.

  20. 2.5D dictionary learning based computed tomography reconstruction

    NASA Astrophysics Data System (ADS)

    Luo, Jiajia; Eri, Haneda; Can, Ali; Ramani, Sathish; Fu, Lin; De Man, Bruno

    2016-05-01

    A computationally efficient 2.5D dictionary learning (DL) algorithm is proposed and implemented in the model- based iterative reconstruction (MBIR) framework for low-dose CT reconstruction. MBIR is based on the minimization of a cost function containing data-fitting and regularization terms to control the trade-off between data-fidelity and image noise. Due to the strong denoising performance of DL, it has previously been considered as a regularizer in MBIR, and both 2D and 3D DL implementations are possible. Compared to the 2D case, 3D DL keeps more spatial information and generates images with better quality although it requires more computation. We propose a novel 2.5D DL scheme, which leverages the computational advantage of 2D-DL, while attempting to maintain reconstruction quality similar to 3D-DL. We demonstrate the effectiveness of this new 2.5D DL scheme for MBIR in low-dose CT. By applying the 2D DL method in three different orthogonal planes and calculating the sparse coefficients accordingly, much of the 3D spatial information can be preserved without incurring the computational penalty of the 3D DL method. For performance evaluation, we use baggage phantoms with different number of projection views. In order to quantitatively compare the performance of different algorithms, we use PSNR, SSIM and region based standard deviation to measure the noise level, and use the edge response to calculate the resolution. Experimental results with full view datasets show that the different DL based algorithms have similar performance and 2.5D DL has the best resolution. Results with sparse view datasets show that 2.5D DL outperforms both 2D and 3D DL in terms of noise reduction. We also compare the computational costs, and 2.5D DL shows strong advantage over 3D DL in both full-view and sparse-view cases.

  1. Chemical PM2.5 Speciation in Major Cities Worldwide

    NASA Astrophysics Data System (ADS)

    Snider, Graydon; Weagle, Crystal; Brauer, Michael; Cohen, Aaron; Gibson, Mark; Liu, Yang; Martins, Vanderlei; Rudich, Yinon; Martin, Randall

    2016-04-01

    We examined the chemical composition of fine particulate matter (PM2.5) across 13 globally dispersed urban locations (including Atlanta, Buenos Aires, Beijing, Manila, and Dhaka), as part of the Surface PARTiculate mAtter Network (SPARTAN). At each site sampling was conducted over 4 to 24 months for the years 2013 to 2015. Analysis of filter samples revealed that several PM2.5 chemical components varied by more than an order of magnitude between sites. Ammonium sulfate ranged from 2 μg m-3 (Ilorin) to 17 μg m-3 (Kanpur). Ammonium nitrate ranged from 0.2 μg m-3 (Atlanta) to 6.7 μg m-3 (Kanpur). Effective black carbon ranged from 0.4 μg m-3 (Atlanta) to 5 μg m-3 (Dhaka and Kanpur). The all-site mean values of major PM2.5 constituents were ammonium sulfate (20 ± 10 %), crustal material (12 ± 6.5%), effective black carbon (10 ± 7.4 %), ammonium nitrate (3.7 ± 2.5%), sea salt (2.2 ± 1.5%), trace element oxides (0.9 ± 0.7 %), water (7.2 ± 3.0%) and residue materials (44 ± 24%). Based on the evaluation with collocated studies we treated residue material as mostly organic. Major ions generally agreed well with previous studies at the same urban locations (e.g. sulfate fractions agreed within 4% for eight out of 11 collocation comparisons). Enhanced crustal material (CM) concentrations with high Zn:Al ratios at large cities (e.g. Hanoi, Dhaka, Manila) imply significant anthropogenic CM contributions that deserve more attention. Detailed chemical speciation also aided our characterization of site-specific PM2.5 water retention. The expected water contribution to aerosols was calculated via the hygroscopicity parameter for each filter. Hourly PM2.5 at specified relative humidity (35%) was inferred from nephelometer measurements of light scatter at ambient relative humidity and 9-day filter measurements of PM2.5 mass. Our PM2.5 estimates compared favorably with a beta attenuation monitor (BAM) at the nearby US embassy in Beijing, with a coefficient of variation

  2. Using PM(2.5) lanthanoid elements and nonparametric wind regression to track petroleum refinery FCC emissions.

    PubMed

    Du, Li; Turner, Jay

    2015-10-01

    A long term air quality study is being conducted in Roxana, Illinois, USA, at the fenceline of a petroleum refinery. Measurements include 1-in-6 day 24-hour integrated ambient fine particulate matter (PM2.5) speciation following the Chemical Speciation Network (CSN) sampling and analysis protocols. Lanthanoid elements, some of which are tracers of fluidized-bed catalytic cracker (FCC) emissions, are also measured by inductively coupled plasma-mass spectrometry (ICP-MS) after extraction from PM2.5 using hot block-assisted acid digestion. Lanthanoid recoveries of 80-90% were obtained for two ambient particulate matter standard reference materials (NIST SRM 1648a and 2783). Ambient PM2.5 La patterns could be explained by a two-source model representing resuspended soil and FCC emissions with enhanced La/Ce ratios when impacted by the refinery. Nonparametric wind regression demonstrates that when the monitoring station was upwind of the refinery the mean La/Ce ratio is consistent with soil and when the monitoring station is downwind of the refinery the mean ratio is more than four times higher for bearings that corresponds to maximum impacts. Source apportionment modeling using EPA UNMIX and EPA PMF could not reliably apportion PM2.5 mass to the FCC emissions. However, the weight of evidence is that such contributions are small with no large episodes observed for the 164 samples analyzed. This study demonstrates the applicability of a hot block-assisted digestion protocol for the extraction of lanthanoid elements as well as insights obtained from long-term monitoring data including wind direction-based analyses.

  3. Effect of estrogen administration on rat liver 2-5A synthetase activity.

    PubMed

    Smekens, M; Dumont, J E; Degeyter, A; Galand, P

    1986-08-01

    Interferon-induced 2-5A synthetase is also present in various cells and tissues in the absence of any interferon treatment. The activity of this enzyme, which synthesizes a series of oligoadenylates, ppp(A2'p)n5'A (collectively referred to as 2-5A), was previously shown to vary with the growth status of liver tissue i.e., it decreased before and during the peak of DNA synthesis activity induced in rat liver by a two third hepatectomy. In the course of studies aimed at testing the hypothesis that 2-5A synthetase activity might exert negative control on normal cell growth and multiplication, we show here that a treatment of ovariectomized rats with a single dose of estradiol-17beta (100 micrograms/100 g body weight) induced a transient increase in the [3H]thymidine labelling index in the liver after 24 h and markedly decreased the 2-5A synthetase activity. A time course study revealed that 2-5A synthetase activity started to decrease after 3 h, reaching a minimal value (10% of the control level) after 12 h, then slowly increased to come back to control level at 48 h. These results, together with our similar data on regenerating liver, suggest that low 2-5A synthetase activity is permissive for acquisition of proliferative 'competence' by G0 cells. PMID:3730433

  4. Chemical composition of PM2.5 from two tunnels with different vehicular fleet characteristics.

    PubMed

    Cui, Min; Chen, Yingjun; Tian, Chongguo; Zhang, Fan; Yan, Caiqing; Zheng, Mei

    2016-04-15

    The chemical compositions of PM2.5 including OC, EC, water soluble ions, elements, and organic components such as polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes, emitted in Wuzushan (WZS) and Kuixinglou (KXL) tunnels were determined. WZS tunnel is a major route for diesel vehicles traveling, while KXL tunnel has limited to diesel vehicles. The results showed that the proportions of the different constituents of PM2.5 in the Wuzushan (WZS) tunnel were OC (27.7%), EC (32.1%), elements (13.9%), and water soluble ions (9.2%). Whereas the chemical profile of PM2.5 in the Kuixinglou (KXL) tunnel was OC (17.7%), EC (10.4%), elements (8.90%), and water soluble ions (8.87%). The emission factors (EFs) of PM2.5 and proportions of SO4(2-) and Pb were decreased by vehicle emission standards and fuel quality policy in China, and the higher molecular weight PAHs (4+5+6 rings) were more abundant than the lower molecular weight PAHs (2+3 rings) in the two tunnels. The proportions of 17A(H)-21B(H)-30-Norhopane and 17A(H)-21B(H)-Hopane in the hopane and sterane were not dependent on the vehicles types. In addition, specific composition profiles for PM2.5 from gasoline-fueled vehicles (GV) and diesel-fueled vehicles (DV) emissions were drafted, which indicated that OC (0.974mg·veh(-1)·km(-1)) was the most abundant component in PM2.5, followed by Fe, Cl(-), and Mg for GV. The relative proportions of the different constituents in the PM2.5 for DV were EC (35.9%), OC (27.2%), elements (12.8%), and water soluble ions (11.7%). Both the PM2.5 EFs and EC proportions in DV were higher than those in GV, and the HMW PAHs were the dominant PAHs for both GV and DV. The PM2.5 emissions from the vehicles in Yantai were 581±513tons to 1353±1197tons for GV, and 19,627±2477tons to 23,042±2887tons for DV, respectively. PMID:26808403

  5. Chemical composition of PM2.5 from two tunnels with different vehicular fleet characteristics.

    PubMed

    Cui, Min; Chen, Yingjun; Tian, Chongguo; Zhang, Fan; Yan, Caiqing; Zheng, Mei

    2016-04-15

    The chemical compositions of PM2.5 including OC, EC, water soluble ions, elements, and organic components such as polycyclic aromatic hydrocarbons (PAHs), hopanes, and steranes, emitted in Wuzushan (WZS) and Kuixinglou (KXL) tunnels were determined. WZS tunnel is a major route for diesel vehicles traveling, while KXL tunnel has limited to diesel vehicles. The results showed that the proportions of the different constituents of PM2.5 in the Wuzushan (WZS) tunnel were OC (27.7%), EC (32.1%), elements (13.9%), and water soluble ions (9.2%). Whereas the chemical profile of PM2.5 in the Kuixinglou (KXL) tunnel was OC (17.7%), EC (10.4%), elements (8.90%), and water soluble ions (8.87%). The emission factors (EFs) of PM2.5 and proportions of SO4(2-) and Pb were decreased by vehicle emission standards and fuel quality policy in China, and the higher molecular weight PAHs (4+5+6 rings) were more abundant than the lower molecular weight PAHs (2+3 rings) in the two tunnels. The proportions of 17A(H)-21B(H)-30-Norhopane and 17A(H)-21B(H)-Hopane in the hopane and sterane were not dependent on the vehicles types. In addition, specific composition profiles for PM2.5 from gasoline-fueled vehicles (GV) and diesel-fueled vehicles (DV) emissions were drafted, which indicated that OC (0.974mg·veh(-1)·km(-1)) was the most abundant component in PM2.5, followed by Fe, Cl(-), and Mg for GV. The relative proportions of the different constituents in the PM2.5 for DV were EC (35.9%), OC (27.2%), elements (12.8%), and water soluble ions (11.7%). Both the PM2.5 EFs and EC proportions in DV were higher than those in GV, and the HMW PAHs were the dominant PAHs for both GV and DV. The PM2.5 emissions from the vehicles in Yantai were 581±513tons to 1353±1197tons for GV, and 19,627±2477tons to 23,042±2887tons for DV, respectively.

  6. PM 2.5 Airborne Particulates Near Frac Sand Operations.

    PubMed

    Walters, Kristin; Jacobson, Jeron; Kroening, Zachary; Pierce, Crispin

    2015-11-01

    The rapid growth of hydraulic fracturing for oil and gas extraction in the U.S. has led to 135 active "frac" sand mines, processing plants, and rail transfer stations in Wisconsin. Potential environmental health risks include increased truck traffic, noise, ecosystem loss, and groundwater, light, and air pollution. Emitted air contaminants include fine particulate matter (PM2.5) and respirable crystalline silica. Inhalation of fine dust particles causes increased mortality, cardiovascular disease, lung disease, and lung cancer. In the authors' pilot study, use of a filter-based ambient particulate monitor found PM2.5 levels of 5.82-50.8 µg/m3 in six 24-hour samples around frac sand mines and processing sites. Enforcement of the existing U.S. Environmental Protection Agency annual PM2.5 standard of 12 µg/m3 is likely to protect the public from silica exposure risks as well. PM2.5 monitoring around frac sand sites is needed to ensure regulatory compliance, inform nearby communities, and protect public health.

  7. 43 CFR 3472.2-5 - Special qualifications, public bodies.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Special qualifications, public bodies... PROVISIONS AND LIMITATIONS Lease Qualification Requirements § 3472.2-5 Special qualifications, public bodies... public body shall submit: (1) Evidence of the manner in which it is organized; (2) Evidence that it...

  8. Source apportionment of PM2.5 in Seoul, Korea

    NASA Astrophysics Data System (ADS)

    Heo, J.-B.; Hopke, P. K.; Yi, S.-M.

    2009-07-01

    PM2.5 samples were collected at a centrally located urban monitoring site in Seoul, Korea, every third day from March 2003 to December 2006 and analyzed for their chemical constituents. Sources were identified using positive matrix factorization (PMF). A total of 393 samples were obtained during the sampling period, and 20 chemical species were measured. Nine PM2.5 source categories were identified providing physically realistic profiles and interesting insights into the source contributions to the ambient mass concentrations. The major contributors of PM2.5 were secondary nitrate (20.9%), secondary sulfate (20.5%), gasoline-fueled vehicles (17.2%), and biomass burning (12.1%), with lesser contributions from diesel emissions (8.1%), soil (7.4%), industry (6.7%), road salt and two-stroke vehicles (5.1%), and aged sea salt (2.2%). PM2.5 levels in Seoul were influenced by both local urban activities and regional-scale transport. Conditional probability function (CPF) results identified possible source directions of local sources such as motor vehicles (gasoline and diesel), industry, and road salt. Potential source contribution function (PSCF) results showed that possible source areas contributing to the elevated secondary particle concentrations (sulfate and nitrate) in Seoul to be the major industrial areas in China.

  9. Source apportionment of PM2.5 in Seoul, Korea

    NASA Astrophysics Data System (ADS)

    Heo, J.-B.; Hopke, P. K.; Yi, S.-M.

    2008-12-01

    PM2.5 samples were collected at a centrally located urban monitoring site in Seoul, Korea, every third day from March 2003 to December 2006 and analyzed for their chemical constituents. Sources were identified using Positive Matrix Factorization (PMF). A total of 393 samples were obtained during the sampling period, and 20 chemical species were measured. Nine PM2.5 sources were identified providing physically realistic profiles and interesting insights into the source contributions to the ambient mass concentrations. The major sources of PM2.5 were secondary nitrate (20%), secondary sulfate (20%), gasoline-fueled vehicles (17%), and biomass burning (12%), with lesser contributions from diesel emissions (8%), soil (7%), industry (6%), road salt and two-stroke engine (5%), and aged sea salt (2%). PM2.5 levels in Seoul were influenced by both local urban activities and regional-scale transport. Conditional Probability Function (CPF) results identified possible source directions of local sources such as motor vehicles (gasoline and diesel), industry, and road salt. Potential Source Contribution Function (PSCF) results showed that possible source areas contributing to the elevated secondary particle concentrations (sulfate and nitrate) in Seoul to be the major industrial areas in China.

  10. Science in Action Series: AGATE (pt 2/5 )

    NASA Technical Reports Server (NTRS)

    1997-01-01

    This show was made for the Office of Education at NASA Langley. The objective is to make math and science appealing to a middle school audience. This clip (pt 2/5 ) is an animation which tells us a little about the plane itself: including capacity, speed and range.

  11. 2,5-hexanedione-induced immunomodulatory effect in mice

    SciTech Connect

    Upreti, R.K.; Shanker, R.

    1987-06-01

    The immunotoxic potential of 2,5-hexanedione (2,5-Hxdn), the end metabolite of n-hexane/methyl n-butyl ketone, was evaluated in a mouse model involving multiple pathomorphological, hematological, and immunological assays. Young adult male Swiss albino mice were given either single or seven consecutive oral doses of 0.2 x LD/sub 50/ of 2.5-Hxdn. None of the treated mice exhibited any sign of hind limb weakness up to 1 week. On the eighth day, half the animals were sacrificed for initial pathomorphological studies of various organs and the other half were subjected to several immune function tests. The results revealed treatment-related reduction in cellularity of spleen, thymus, and mesentric lymph nodes and pathotoxicological changes. Further, immune function tests such as delayed-type hypersensitivity reaction, plaque-forming cell assay, phagocytosis by adherent peritoneal exudate cells, and resistance to endotoxin shock were considerably impaired. These results suggest that 2,5-Hxdn treatment causes profound impairment of immunity in mice even before the onset of peripheral neuropathy.

  12. PM 2.5 Airborne Particulates Near Frac Sand Operations.

    PubMed

    Walters, Kristin; Jacobson, Jeron; Kroening, Zachary; Pierce, Crispin

    2015-11-01

    The rapid growth of hydraulic fracturing for oil and gas extraction in the U.S. has led to 135 active "frac" sand mines, processing plants, and rail transfer stations in Wisconsin. Potential environmental health risks include increased truck traffic, noise, ecosystem loss, and groundwater, light, and air pollution. Emitted air contaminants include fine particulate matter (PM2.5) and respirable crystalline silica. Inhalation of fine dust particles causes increased mortality, cardiovascular disease, lung disease, and lung cancer. In the authors' pilot study, use of a filter-based ambient particulate monitor found PM2.5 levels of 5.82-50.8 µg/m3 in six 24-hour samples around frac sand mines and processing sites. Enforcement of the existing U.S. Environmental Protection Agency annual PM2.5 standard of 12 µg/m3 is likely to protect the public from silica exposure risks as well. PM2.5 monitoring around frac sand sites is needed to ensure regulatory compliance, inform nearby communities, and protect public health. PMID:26638669

  13. 11 CFR 2.5 - Procedures for closing meetings.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... attached to, and preserved with, the statement required by 11 CFR 2.5(d). (c) Voting procedures. (1) No... each item on an agenda proposed to be closed in whole or in part pursuant to 11 CFR 2.4, or with respect to any information proposed to be withheld under 11 CFR 2.4. (ii) A single vote may be taken...

  14. 11 CFR 2.5 - Procedures for closing meetings.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... attached to, and preserved with, the statement required by 11 CFR 2.5(d). (c) Voting procedures. (1) No... each item on an agenda proposed to be closed in whole or in part pursuant to 11 CFR 2.4, or with respect to any information proposed to be withheld under 11 CFR 2.4. (ii) A single vote may be taken...

  15. 11 CFR 2.5 - Procedures for closing meetings.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... attached to, and preserved with, the statement required by 11 CFR 2.5(d). (c) Voting procedures. (1) No... each item on an agenda proposed to be closed in whole or in part pursuant to 11 CFR 2.4, or with respect to any information proposed to be withheld under 11 CFR 2.4. (ii) A single vote may be taken...

  16. 11 CFR 2.5 - Procedures for closing meetings.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... attached to, and preserved with, the statement required by 11 CFR 2.5(d). (c) Voting procedures. (1) No... each item on an agenda proposed to be closed in whole or in part pursuant to 11 CFR 2.4, or with respect to any information proposed to be withheld under 11 CFR 2.4. (ii) A single vote may be taken...

  17. Extending Interactive Writing into Grades 2-5

    ERIC Educational Resources Information Center

    Roth, Kate; Dabrowski, Joan

    2014-01-01

    Interactive writing is an instructional practice widely considered effective and most appropriate for emergent writers. This article asserts that it is a valuable method for more fluent writers in grades 2-5. It outlines the basic lesson sequence and proposes four key shifts to adapt interactive writing for older, more fluent writers: 1) The…

  18. 75 FR 14259 - Transportation Conformity Rule PM2.5

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-24

    .... EPA first promulgated the transportation conformity rule on November 24, 1993 (58 FR 62188), and... a final rule EPA published on July 1, 2004 (69 FR 40004), EPA provided conformity procedures for... Precursors'' (70 FR 24280). This final rule specified transportation-related PM 2.5 precursors and when...

  19. The role of metal components in the cardiovascular effects of PM2.5.

    PubMed

    Niu, Jingping; Liberda, Eric N; Qu, Song; Guo, Xinbiao; Li, Xiaomei; Zhang, Jingjing; Meng, Junliang; Yan, Bing; Li, Nairong; Zhong, Mianhua; Ito, Kazuhiko; Wildman, Rachel; Liu, Hong; Chen, Lung Chi; Qu, Qingshan

    2013-01-01

    Exposure to ambient fine particulate matter (PM2.5) increases risks for cardiovascular disorders (CVD). However, the mechanisms and components responsible for the effects are poorly understood. Based on our previous murine exposure studies, a translational pilot study was conducted in female residents of Jinchang and Zhangye, China, to test the hypothesis that specific chemical component of PM2.5 is responsible for PM2.5 associated CVD. Daily ambient and personal exposures to PM2.5 and 35 elements were measured in the two cities. A total of 60 healthy nonsmoking adult women residents were recruited for measurements of inflammation biomarkers. In addition, circulating endothelial progenitor cells (CEPCs) were also measured in 20 subjects. The ambient levels of PM2.5 were comparable between Jinchang and Zhangye (47.4 and 54.5 µg/m(3), respectively). However, the levels of nickel, copper, arsenic, and selenium in Jinchang were 82, 26, 12, and 6 fold higher than Zhangye, respectively. The levels of C-reactive protein (3.44 ± 3.46 vs. 1.55 ± 1.13), interleukin-6 (1.65 ± 1.17 vs. 1.09 ± 0.60), and vascular endothelial growth factor (117.6 ± 217.0 vs. 22.7 ± 21.3) were significantly higher in Jinchang. Furthermore, all phenotypes of CEPCs were significantly lower in subjects recruited from Jinchang than those from Zhangye. These results suggest that specific metals may be important components responsible for PM2.5-induced cardiovascular effects and that the reduced capacity of endothelial repair may play a critical role. PMID:24386277

  20. The Role of Metal Components in the Cardiovascular Effects of PM2.5

    PubMed Central

    Niu, Jingping; Liberda, Eric N.; Qu, Song; Guo, Xinbiao; Li, Xiaomei; Zhang, Jingjing; Meng, Junliang; Yan, Bing; Li, Nairong; Zhong, Mianhua; Ito, Kazuhiko; Wildman, Rachel; Liu, Hong; Chen, Lung Chi; Qu, Qingshan

    2013-01-01

    Exposure to ambient fine particulate matter (PM2.5) increases risks for cardiovascular disorders (CVD). However, the mechanisms and components responsible for the effects are poorly understood. Based on our previous murine exposure studies, a translational pilot study was conducted in female residents of Jinchang and Zhangye, China, to test the hypothesis that specific chemical component of PM2.5 is responsible for PM2.5 associated CVD. Daily ambient and personal exposures to PM2.5 and 35 elements were measured in the two cities. A total of 60 healthy nonsmoking adult women residents were recruited for measurements of inflammation biomarkers. In addition, circulating endothelial progenitor cells (CEPCs) were also measured in 20 subjects. The ambient levels of PM2.5 were comparable between Jinchang and Zhangye (47.4 and 54.5µg/m3, respectively). However, the levels of nickel, copper, arsenic, and selenium in Jinchang were 82, 26, 12, and 6 fold higher than Zhangye, respectively. The levels of C-reactive protein (3.44±3.46 vs. 1.55±1.13), interleukin-6 (1.65±1.17 vs. 1.09±0.60), and vascular endothelial growth factor (117.6±217.0 vs. 22.7±21.3) were significantly higher in Jinchang. Furthermore, all phenotypes of CEPCs were significantly lower in subjects recruited from Jinchang than those from Zhangye. These results suggest that specific metals may be important components responsible for PM2.5-induced cardiovascular effects and that the reduced capacity of endothelial repair may play a critical role. PMID:24386277

  1. [PM2.5 pollution and aerosol optical properties in fog and haze days during autumn and winter in Beijing area].

    PubMed

    Zhao, Xiu-Juan; Pu, Wei-Wei; Meng, Wei; Ma, Zhi-Qiang; Dong, Fan; He, Di

    2013-02-01

    A study on the PM2.5 pollution and aerosol optical properties in haze-fog days was carried out from Sep. 1st to Dec. 7th, 2011 in Beijing area by using PM2.5 concentration, aerosol scattering coefficient (sigma sca) and absorption coefficient (sigma abs) measured under urban and rural environment. The effect of weather condition on the PM25 pollution and aerosol optical properties was discussed as well. The results showed that the PM2.5 concentration, sigma sca and sigma abs, were evidently higher in haze-fog days than those in non-haze-fog days. The average PM2.5 concentrations in haze-fog days with values of 97.6 microg m-3 and 64.4 microg.m-3 were as 3.3 and 4.8 times as those in non-haze-fog days at urban and rural stations, respectively. The higher PM2.5 concentration in urban area resulted in the more frequent fog and haze phenomena than that in rural area. The PM25 concentration, sigma sca, and sigma abs were significantly higher in urban area than that in rural area in mist days, while relatively close in mist-haze days. This difference suggested that the effect of regional transport of pollution was relatively evident in mist-haze days but weak in mist day. In fog days the sigma sca showed no evident difference between urban and rural area, and was the highest in all types of fog and haze weather. The scattering property of aerosol was the strongest in fog days. The different weather conditions resulted in various characteristics of spatial distribution of PM2.5 concentration, sigma sca and sigma abs, as well as the strength of PM2,5 pollution and aerosol extinction. The pollutants transported by the strong southwest wind above the boundary layer and subsided in the boundary layer companying with the local accumulation of pollutants due to the weak diffusion resulted in the most serious haze-fog episode with the strongest PM2.5 pollution and aerosol extinction.

  2. Assessing PM2.5 Exposures with High Spatiotemporal Resolution across the Continental United States.

    PubMed

    Di, Qian; Kloog, Itai; Koutrakis, Petros; Lyapustin, Alexei; Wang, Yujie; Schwartz, Joel

    2016-05-01

    A number of models have been developed to estimate PM2.5 exposure, including satellite-based aerosol optical depth (AOD) models, land-use regression, or chemical transport model simulation, all with both strengths and weaknesses. Variables like normalized difference vegetation index (NDVI), surface reflectance, absorbing aerosol index, and meteoroidal fields are also informative about PM2.5 concentrations. Our objective is to establish a hybrid model which incorporates multiple approaches and input variables to improve model performance. To account for complex atmospheric mechanisms, we used a neural network for its capacity to model nonlinearity and interactions. We used convolutional layers, which aggregate neighboring information, into a neural network to account for spatial and temporal autocorrelation. We trained the neural network for the continental United States from 2000 to 2012 and tested it with left out monitors. Ten-fold cross-validation revealed a good model performance with a total R(2) of 0.84 on the left out monitors. Regional R(2) could be even higher for the Eastern and Central United States. Model performance was still good at low PM2.5 concentrations. Then, we used the trained neural network to make daily predictions of PM2.5 at 1 km × 1 km grid cells. This model allows epidemiologists to access PM2.5 exposure in both the short-term and the long-term. PMID:27023334

  3. Assessing PM2.5 Exposures with High Spatiotemporal Resolution across the Continental United States.

    PubMed

    Di, Qian; Kloog, Itai; Koutrakis, Petros; Lyapustin, Alexei; Wang, Yujie; Schwartz, Joel

    2016-05-01

    A number of models have been developed to estimate PM2.5 exposure, including satellite-based aerosol optical depth (AOD) models, land-use regression, or chemical transport model simulation, all with both strengths and weaknesses. Variables like normalized difference vegetation index (NDVI), surface reflectance, absorbing aerosol index, and meteoroidal fields are also informative about PM2.5 concentrations. Our objective is to establish a hybrid model which incorporates multiple approaches and input variables to improve model performance. To account for complex atmospheric mechanisms, we used a neural network for its capacity to model nonlinearity and interactions. We used convolutional layers, which aggregate neighboring information, into a neural network to account for spatial and temporal autocorrelation. We trained the neural network for the continental United States from 2000 to 2012 and tested it with left out monitors. Ten-fold cross-validation revealed a good model performance with a total R(2) of 0.84 on the left out monitors. Regional R(2) could be even higher for the Eastern and Central United States. Model performance was still good at low PM2.5 concentrations. Then, we used the trained neural network to make daily predictions of PM2.5 at 1 km × 1 km grid cells. This model allows epidemiologists to access PM2.5 exposure in both the short-term and the long-term.

  4. Design and signal processing of a sector SSPA for PM2.5 monitoring

    NASA Astrophysics Data System (ADS)

    Wu, Kaihua; Ma, Li; Guo, Miao; Jiang, Peng

    2008-03-01

    PM2.5 is the chief air pollutants in most Chinese City. The PM2.5 parameter was usually evaluated by the weight per unit volume (mg/m 3) and the size was generally ignored. A method measuring the particle size distribution of PM2.5 based on light scattering was put forward. A special sector sensor, SSPA(Self Scanning Photodiode Array), was designed to detect the distribution of weak space light energy. We researched a special optoelectronic detector with sector detection area. The sensor has high sensitivity and high reliability. It's suitable for detecting the distribution of space light energy, especially the diffraction and scattering energy distribution. The paper researched the signal processing method. Based on the principle and characteristics of SSPA, a signal acquisition and processing method controlled by computer was introduced. The amplification of weak signal, the matching of time sequence, the fast peak holding with low leakage, the high speed A/D conversion and nonlinear correction were discussed. The method can acquire the peak signal of every ring of sector SSPA with high accuracy and in real time. The particle size distribution of PM2.5 acquired in Hangzhou City was analyzed. Results showed that the particles with diameter below 2.5um were above 90%.

  5. Higher-order in time "quasi-unconditionally stable" ADI solvers for the compressible Navier-Stokes equations in 2D and 3D curvilinear domains

    NASA Astrophysics Data System (ADS)

    Bruno, Oscar P.; Cubillos, Max

    2016-02-01

    This paper introduces alternating-direction implicit (ADI) solvers of higher order of time-accuracy (orders two to six) for the compressible Navier-Stokes equations in two- and three-dimensional curvilinear domains. The higher-order accuracy in time results from 1) An application of the backward differentiation formulae time-stepping algorithm (BDF) in conjunction with 2) A BDF-like extrapolation technique for certain components of the nonlinear terms (which makes use of nonlinear solves unnecessary), as well as 3) A novel application of the Douglas-Gunn splitting (which greatly facilitates handling of boundary conditions while preserving higher-order accuracy in time). As suggested by our theoretical analysis of the algorithms for a variety of special cases, an extensive set of numerical experiments clearly indicate that all of the BDF-based ADI algorithms proposed in this paper are "quasi-unconditionally stable" in the following sense: each algorithm is stable for all couples (h , Δt)of spatial and temporal mesh sizes in a problem-dependent rectangular neighborhood of the form (0 ,Mh) × (0 ,Mt). In other words, for each fixed value of Δt below a certain threshold, the Navier-Stokes solvers presented in this paper are stable for arbitrarily small spatial mesh-sizes. The second-order formulation has further been rigorously shown to be unconditionally stable for linear hyperbolic and parabolic equations in two-dimensional space. Although implicit ADI solvers for the Navier-Stokes equations with nominal second-order of temporal accuracy have been proposed in the past, the algorithms presented in this paper are the first ADI-based Navier-Stokes solvers for which second-order or better accuracy has been verified in practice under non-trivial (non-periodic) boundary conditions.

  6. Real-time object recognition in multidimensional images based on joined extended structural tensor and higher-order tensor decomposition methods

    NASA Astrophysics Data System (ADS)

    Cyganek, Boguslaw; Smolka, Bogdan

    2015-02-01

    In this paper a system for real-time recognition of objects in multidimensional video signals is proposed. Object recognition is done by pattern projection into the tensor subspaces obtained from the factorization of the signal tensors representing the input signal. However, instead of taking only the intensity signal the novelty of this paper is first to build the Extended Structural Tensor representation from the intensity signal that conveys information on signal intensities, as well as on higher-order statistics of the input signals. This way the higher-order input pattern tensors are built from the training samples. Then, the tensor subspaces are built based on the Higher-Order Singular Value Decomposition of the prototype pattern tensors. Finally, recognition relies on measurements of the distance of a test pattern projected into the tensor subspaces obtained from the training tensors. Due to high-dimensionality of the input data, tensor based methods require high memory and computational resources. However, recent achievements in the technology of the multi-core microprocessors and graphic cards allows real-time operation of the multidimensional methods as is shown and analyzed in this paper based on real examples of object detection in digital images.

  7. Long-term variation of black carbon and PM2.5 in Beijing, China with respect to meteorological conditions and governmental measures.

    PubMed

    Chen, Yuan; Schleicher, Nina; Fricker, Mathieu; Cen, Kuang; Liu, Xiu-Li; Kaminski, Uwe; Yu, Yang; Wu, Xue-Fang; Norra, Stefan

    2016-05-01

    Black carbon (BC) and PM2.5 were studied for nine years from 2005 to 2013 in the Beijing urban area. The overall weekly average mass concentrations of BC and PM2.5 were 4.3 and 66.8 μg/m³. PM2.5 annual means of the nine years are around 2 times of the standard (GB3095-2012) in China, and are 5-7 times higher than the WHO standard. The Beijing Olympic Games in 2008 was a milestone to mitigate aerosol pollution. Temporal distribution of BC shows a distinct declining trend, and annual mean mass concentrations of PM2.5 after 2008 were lower than those before 2008 but increased from 2011 to 2013. Wind rose plots show that high BC concentrations are usually associated with low wind speed of northeastern or southwestern winds, generally causing poor visibility. Governmental mitigation measures such as traffic restriction despite increased motor vehicle numbers and gasoline consumption and industry relocation with declining consumption of coal and coke were successful in reducing BC emissions. Annual mean of BC was reduced by 38% in 2013 compared to 2005. However, BC contamination in Beijing is still severe when compared to other urban areas around the world. PMID:26854696

  8. Younger age at initiation of the human papillomavirus (HPV) vaccination series is associated with higher rates of on-time completion.

    PubMed

    St Sauver, Jennifer L; Rutten, Lila J Finney; Ebbert, Jon O; Jacobson, Debra J; McGree, Michaela E; Jacobson, Robert M

    2016-08-01

    Vaccination rates for human papillomavirus (HPV) have remained disappointingly low. It is critical to identify methods to increase on-time vaccine series completion rates (before 13 or 15years). To determine whether younger age (9 to 10years of age) at HPV vaccine series initiation was associated with improved on-time completion rates compared to initiation at 11 to 12years, we examined the prevalence of on-time HPV vaccine series completion rates from August 2006 through December 2012 in a large, population-based cohort of children and adolescents (aged 9.5 to 27years) residing in Olmsted County, MN on December 31, 2012 (n=36,223). We compared age at vaccine initiation between individuals who successfully completed both 2 and 3 doses of the vaccination series on-time (before age 13.5 or 15.0years) using multivariate logistic regression. On-time completion of both 2 and 3 doses of the vaccine series by age 13.5 or 15.0years was significantly associated with initiation at 9 to 10years as compared to 11 to 12years after adjusting for sex, race, insurance status, frequent health care visits, and year of first vaccination (all p<.01). Interventions focused on beginning the vaccination series at 9 to 10years of age may result in higher rates of timely series completion.

  9. DEVELOPMENT AND EVALUATION OF A CONTINUOUS COARSE (PM10-PM2.5) PARTICLE MONITOR

    EPA Science Inventory

    In this paper, we describe the development and laboratory and field evaluation of a continuous coarse (2.5-10 um) particle mass (PM) monitor that can provide reliable measurements of the coarse mass (CM) concentrations in time intervals as short as 5-10 min. The operating princ...

  10. Personal exposure to PM 2.5 and element composition—A comparison between outdoor and indoor workers from two Mexican cities

    NASA Astrophysics Data System (ADS)

    Tovalin-Ahumada, Horacio; Whitehead, Lawrence; Blanco, Salvador

    Many individuals work outdoors in the formal and informal economy of the large urban areas in developing countries, where they are potentially exposed for long periods to high concentrations of ambient airborne particulate matter (PM). This study describes the personal exposures to PM of 2.5 μm aerodynamic diameter and smaller (PM 2.5) for a sample of outdoor and indoor workers in two cities, Mexico City and Puebla, in central Mexico. Thirty-six workers in Mexico City and 17 in Puebla were studied. Thirty were outdoor workers (i.e., taxi and bus drivers, street vendors, and vehicle inspectors) and 23 were indoor (office) workers. Their personal exposures to PM 2.5 were monitored for a mean 19-h period. In Mexico City, the street vendors and taxi drivers overall exposures were significantly higher than indoor workers were. In Puebla, bus drivers had a higher overall exposure than vehicle inspectors or indoor workers. Most of the exposures were above the 65 μg m -3 24-h Mexican standard. In Mexico City, exposures to Si, Ti, Cr, Mn, Fe, Ni, Cu, Mo and Cd were higher for outdoor than for indoor workers. In Puebla, exposures to Si, S, K, Ca, Ti, V, Mn, and Zn also were higher for outdoor workers. In Mexico City outdoor workers exposures to Cu, Pb, Cr, Se and Mo were 4 or more times higher than for Puebla outdoor workers, while Puebla outdoor workers' exposures to V, Si, Fe and Ca were 3 or more times higher than Mexico City outdoor workers. These results suggest that for these outdoor workers the elevated local ambient air PM concentrations and an extended period spent outside are more important contributors to total exposures than indoor concentrations. These workers could be at particular risk of increased morbidity and mortality associated with ambient PM.

  11. Tunable and selective conversion of 5-HMF to 2,5-furandimethanol and 2,5-dimethylfuran over copper-doped porous metal oxides.

    PubMed

    Kumalaputri, Angela J; Bottari, Giovanni; Erne, Petra M; Heeres, Hero J; Barta, Katalin

    2014-08-01

    Tunable and selective hydrogenation of the platform chemical 5-hydroxymethylfurfural into valuable C6 building blocks and liquid fuel additives is achieved with copper-doped porous metal oxides in ethanol. A new catalyst composition with improved hydrogenation/hydrogenolysis activity is obtained by introducing small amounts of ruthenium dopant into the previously reported Cu(0.59) Mg2.34 Al1.00 structure. At a mild reaction temperature (100 °C), 2,5-furandimethanol is obtained with excellent selectivity up to >99%. Higher reaction temperatures (220 °C) favor selective deoxygenation to 2,5-dimethylfuran and minor product 2,5-dimethyltetrahydrofuran with a combined yield as high as 81%. Notably, these high product yields are maintained at a substrate concentration up to 10 wt% and a low catalyst loading. The influence of different alcohol solvents on product selectivity is explored. Furthermore, reaction intermediates formed at different reaction temperatures are identified. The composition of these product mixtures provides mechanistic insight into the nature of the reduction pathways that influence product selectivity. The catalysts are characterized by elemental analysis, TEM, and BET techniques before and after the reaction. Catalyst recycling experiments are conducted in batch and in a continuous-flow setup. PMID:24924637

  12. PM2.5 pollution episode and its contributors from 2011 to 2013 in urban Shanghai, China

    NASA Astrophysics Data System (ADS)

    Wang, H. L.; Qiao, L. P.; Lou, S. R.; Zhou, M.; Chen, J. M.; Wang, Q.; Tao, S. K.; Chen, C. H.; Huang, H. Y.; Li, L.; Huang, C.

    2015-12-01

    Shanghai has suffered from severe fine particle (PM2.5) pollution in recent years. The characterization and formation mechanism of PM2.5 pollution episodes were investigated in the present study based on 3-year on-line measurements of PM2.5 chemical compositions with the temporal resolution of 1 h from 2011 to 2013 in Shanghai. Pollution episodes with PM2.5 mass higher than 75 μg/m3 occurred ˜1400 h annually, which inserted the annual extra PM2.5 mass of 14 μg/m3 into the level of 33 μg/m3 without pollution episodes taken into account. Three kinds of typical episodes were identified as biomass burning events, suspended dust events, and fireworks events, which extra contributed ˜1.5 μg/m3 relative to PM2.5 mass of clean periods. Most of pollution episodes were attributed to multiple and complex mechanisms, characterized by high contribution of the secondary inorganic components (e.g. nitrate, sulfate and ammonium) and carbonaceous matters, which dominated the monthly variations of PM2.5 mass. During the complex episodes, the increasing contribution of nitrate mass concentration to PM2.5 burden was observed. The present study highlighted the necessity to pay more attention to the secondary pollution. The reduction of precursor gases emissions was essential to mediate the severe PM2.5 pollution in Shanghai megacity.

  13. PLSS 2.5 Fan Design and Development

    NASA Technical Reports Server (NTRS)

    Quinn, Gregory; Carra, Michael; Converse, David; Chullen, Cinda

    2015-01-01

    NASA is building a high fidelity prototype of an advanced portable life support system (PLSS) as part of the Advanced Exploration Systems Program. This new PLSS, designated as PLSS 2.5, will advance component technologies and systems knowledge in order to inform a future flight program. The oxygen ventilation loop of its predecessor, PLSS 2.0, is driven by a centrifugal fan developed using specifications from the Constellation Program. PLSS technology and system parameters have matured to the point where the existing fan will not perform adequately for the new prototype. In addition, areas of potential improvement have been identified with the existing fan that could be addressed in a new design. As a result, a new fan was designed and tested for the PLSS 2.5.

  14. Ambiphilic boron in 1,4,2,5-diazadiborinine.

    PubMed

    Wang, Baolin; Li, Yongxin; Ganguly, Rakesh; Hirao, Hajime; Kinjo, Rei

    2016-01-01

    Boranes have long been known as the archetypal Lewis acids owing to an empty p-orbital on the boron centre. Meanwhile, Lewis basic tricoordinate boranes have been developed in recent years. Here we report the synthesis of an annulated 1,4,2,5-diazadiborinine derivative featuring boron atoms that exhibit both Lewis acidic and basic properties. Experimental and computational studies confirmed that two boron atoms in this molecule are spectroscopically equivalent. Nevertheless, this molecule cleaves C-O, B-H, Si-H and P-H bonds heterolytically, and readily undergoes [4+2] cycloaddition reaction with non-activated unsaturated bonds such as C=O, C=C, C≡C and C≡N bonds. The result, thus, indicates that the indistinguishable boron atoms in 1,4,2,5-diazadiborinine act as both nucleophilic and electrophilic centres, demonstrating ambiphilic nature. PMID:27279265

  15. Ambiphilic boron in 1,4,2,5-diazadiborinine

    PubMed Central

    Wang, Baolin; Li, Yongxin; Ganguly, Rakesh; Hirao, Hajime; Kinjo, Rei

    2016-01-01

    Boranes have long been known as the archetypal Lewis acids owing to an empty p-orbital on the boron centre. Meanwhile, Lewis basic tricoordinate boranes have been developed in recent years. Here we report the synthesis of an annulated 1,4,2,5-diazadiborinine derivative featuring boron atoms that exhibit both Lewis acidic and basic properties. Experimental and computational studies confirmed that two boron atoms in this molecule are spectroscopically equivalent. Nevertheless, this molecule cleaves C–O, B–H, Si–H and P–H bonds heterolytically, and readily undergoes [4+2] cycloaddition reaction with non-activated unsaturated bonds such as C=O, C=C, C≡C and C≡N bonds. The result, thus, indicates that the indistinguishable boron atoms in 1,4,2,5-diazadiborinine act as both nucleophilic and electrophilic centres, demonstrating ambiphilic nature. PMID:27279265

  16. Long term observations of PM2.5-associated PAHs: Comparisons between normal and episode days

    NASA Astrophysics Data System (ADS)

    Wang, Jia; Li, Xiao; Jiang, Nan; Zhang, Wenkai; Zhang, Ruiqin; Tang, Xiaoyan

    2015-03-01

    The pollution characteristic of fine particular matter (PM2.5) and associated polycyclic aromatic hydrocarbons (PAHs) are currently drawing a great deal of interest because of their influence on environment and health. In this study, PM2.5 was collected from 2011 to 2013 (n = 188) in a suburban area of Zhengzhou, China. 16-PAHs were analyzed to determine the concentration, seasonal variation and potential sources during normal days and episode events. The total mass of 16 PAHs and PM2.5 were in the range of 7-961 ng m-3 and 55-697 μg m-3, with a 3-year average of 174 ng m-3 and 194 μg m-3 respectively. Winter is most polluted for both PM2.5 and PAHs. Average PAH and PM2.5 concentrations during three episode events are 454 ng m-3 and 453 μg m-3, respectively, much higher than values during normal days (299 ng m-3 and 180 μg m-3, respectively). Ratios of Σ16PAH/PM2.5 varied with seasons and concentrations of PM2.5, but showed a negative correlation with PM2.5 concentrations during episode events. The dominant components of PAHs are Benzo[b]fluoranthene, Chrysene, Fluoranthene, and Benzo[k]fluoranthene, Benz[a]anthracene, Pyrene, Indeno(1,2,3-cd)pyrene and their total concentrations vary from 27 to 342 ng m-3, accounting for 58-82% (average = 73%) of 16 PAHs. The Benzo[a]pyrene (Bap) concentration obtained was 9.4 ng m-3 (3-year average), exceeding nearly one order of magnitude of ambient air BaP standard (annual average: 1.0 ng m-3) in China. Diagnose ratios and Positive Matrix Factorization results show that coal combustion, vehicles, coking plant, and biomass burning are main sources for PAHs in this area. The high concentrations of PM2.5 and PAHs, especially during episode events, reflected a potential health problem for nearby public and the necessity of air pollution control for both stationary and mobile sources.

  17. Comprehensive characterization of PM2.5 aerosols in Singapore

    NASA Astrophysics Data System (ADS)

    Balasubramanian, R.; Qian, W.-B.; Decesari, S.; Facchini, M. C.; Fuzzi, S.

    2003-08-01

    A comprehensive characterization of PM2.5 aerosols collected in Singapore from January through December 2000 is presented. The annual average mass concentration of PM2.5 was 27.2 μg/m3. The atmospheric loading of PM2.5 was elevated sporadically from March through May, mainly due to advection of biomass burning (deliberate fires to clear plantation areas) impacted air masses from Sumatra, Indonesia. Satellite images of the area, trajectory calculations, and surface wind direction data are in support of the transport of pyrogenic products from Sumatra toward Singapore. Aerosol samples collected during the dry season were analyzed for water-soluble ions, water-soluble organic compounds (WSOC), elemental carbon (EC), organic carbon, and trace elements using a number of analytical techniques. The major components were sulfate, EC, water-soluble carbonaceous materials, and water-insoluble carbonaceous materials. Aerosol WSOC were characterized based on a combination of chromatographic separations by ion exchange chromatography, functional group investigation by proton nuclear magnetic resonance, and total organic carbon determination. The comprehensive chemical characterization of PM2.5 particles revealed that both non-sea-salt sufate (nss-SO42-) and carbonaceous aerosols mainly contributed to the increase in the mass concentration of aerosols during the smoke haze period. Using a mass closure test (a mass balance), we determined whether the physical measurement of gravimetric fine PM concentration of a sample is equal to the summed concentrations of the individually identified chemical constituents (measured or inferred) in the sample. The sum of the determined groups of aerosol components and the gravimetrically determined mass agreed reasonably well. Principal component analysis was performed from the combined data set, and five factors were observed: a soil dust component, a metallurgical industry factor, a factor representing emissions from biomass burning and

  18. Air Pollution Exposure Model for Individuals (EMI) in Health Studies: Evaluation for Ambient PM2.5

    EPA Science Inventory

    Health studies of fine particulate matter (PM2.5) often use outdoor concentrations as exposure surrogates, which fail to account for indoor attenuation of ambient PM2.5 and time indoors. To address these limitations, we developed an air pollution exposure model for individuals (E...

  19. The concentrations and sources of PM 2.5 in metropolitan New York City

    NASA Astrophysics Data System (ADS)

    Qin, Youjun; Kim, Eugene; Hopke, Philip K.

    The concentration time series of chemical species measured in PM 2.5 samples from four speciation trend network (STN) sites in the New York City metropolitan area and a upwind background site were explored. PM 2.5 concentrations and chemical compositions measured in metropolitan area of New York City are uniform. About 69-82% of PM 2.5 mass derives from transport. The most important constituents of the PM 2.5 were SO42-, NH 4 and NO3- and account 54-67% of PM 2.5 mass. More than 93% of SO42- and about 54-65% of NO3- are likely to have been transported into the NYC area based on the concentrations observed at the background site. Backward air parcel trajectories indicate that coal-fired power plants in the border area among West Virginia, Ohio and Pennsylvania are related to typical high PM 2.5 events having peak secondary pollutant concentrations in New York City. Positive matrix factorization (PMF) was applied to identify the PM 2.5 sources and estimate the source contributions. Sources common to all five sites included secondary sulfate, secondary nitrate, soil and aged sea salt. Oil combustion was identified at four of the sites. At the Elizabeth site, the oil combustion source appears to show an influence from ship emissions. Motor vehicles were apportioned into two sources (gasoline and diesel) at three site and three sources at the Elizabeth site, probably because of its proximity to a major interstate highway. At the Queens College site, only a combined motor vehicle factor could be resolved. The source profiles, source contributions and seasonal or weekday variations derived by PMF are compared to source inventories for the area. It appears that there were more vehicle exhausts and less dust and wood smoke than are indicated by the source inventories.

  20. PM2.5 constituents and oxidative DNA damage in humans.

    PubMed

    Wei, Yongjie; Han, In-Kyu; Shao, Min; Hu, Min; Zhang, O Junfeng; Tang, Xiaoyan

    2009-07-01

    Previous studies suggested that certain constituents of ambient PM2.5 can induce or increase oxidative stress in biological systems. The present study is designed to examine whether exposure to traffic generated particles increases the burden of oxidative stress in humans and to identify specific PM2.5 constituents responsible for pollution-induced oxidative stress. We recruited two nonsmoking security guards who worked at a university campus gate by a heavily trafficked road. Pre- and post-workshift spot urines were collected on each of the 29 days of measurement. Concentrations of PM2.5 mass and 126 chemical species were measured at the worksite and a campus background site simultaneously. Urine samples were analyzed for 8-hydroxy-2'-deoxyguanosine (8-OHdG). Factor analysis and linear mixed-effects regression models were used in statistical analyses. Three clusters of PM2.5 species were identified, including PAHs, metals, and polar organic compounds. Urinary concentrations of 8-OHdG increased by > 3 times following an eight-hour workshift in participants. Pre-workshift urinary concentrations of 8-OHdG were associated with PM2.5 concentrations at the background site. Post-workshift 8-OHdG concentrations were significantly and positively associated with PM2.5 mass, PAHs, and metals, but not polar organic species, measured at the worksite. Our findings provide direct evidence in humans that PM compositions are important in increasing oxidative stress burdens. Our results support that PAHs and metals are biologically active constituents of PM2.5 with regards to the induction of oxidative DNA damages in the human body. PMID:19673262

  1. 2.5D Cartoon Hair Modeling and Manipulation.

    PubMed

    Yeh, Chih-Kuo; Jayaraman, Pradeep Kumar; Liu, Xiaopei; Fu, Chi-Wing; Lee, Tong-Yee

    2015-03-01

    This paper addresses a challenging single-view modeling and animation problem with cartoon images. Our goal is to model the hairs in a given cartoon image with consistent layering and occlusion, so that we can produce various visual effects from just a single image. We propose a novel 2.5D modeling approach to deal with this problem. Given an input image, we first segment the hairs of the cartoon character into regions of hair strands. Then, we apply our novel layering metric, which is derived from the Gestalt psychology, to automatically optimize the depth ordering among the hair strands. After that, we employ our hair completion method to fill the occluded part of each hair strand, and create a 2.5D model of the cartoon hair. By using this model, we can produce various visual effects, e.g., we develop a simplified fluid simulation model to produce wind blowing animations with the 2.5D hairs. To further demonstrate the applicability and versatility of our method, we compare our results with real cartoon hair animations, and also apply our model to produce a wide variety of hair manipulation effects, including hair editing and hair braiding. PMID:26357063

  2. Eco-toxicological bioassay of atmospheric fine particulate matter (PM2.5) with Photobacterium Phosphoreum T3.

    PubMed

    Wang, Wenxin; Shi, Chanzhen; Yan, Yan; Yang, Yunfei; Zhou, Bin

    2016-11-01

    A bioluminescent bacterium, Photobacterium phosphoreum T3 (PPT3), was used as a bio-indicator for the atmospheric fine particulate matter (PM2.5) to determine the eco-toxicity of PM2.5. The PM2.5 contains toxic chemicals, which reduce light output. The PM2.5 samples were collected in the period from March 2014 to January 2015 in Nanjing and analyzed for the chemical composition versus their eco-toxicity. The eco-toxicological responses of each toxicant were detected in PM2.5 samples with PPT3. The dose-response curves obtained were verified using the Weibull fitting function. According to the measured EC50 values (EC50, the concentration of a toxicant that inhibits 50% of the bioluminescence), the toxicity sequence was: B[a]P>hexa-PCB>tetra-PCB>tri-PCB>Pb(2+)>DEHP>Cu(2+)>DBP>BDE209>Zn(2+)>DMP>DEP, where B[a]P is benzo(a)pyrene, PCB is polychlorinated biphenyl, DEHP is diethylhexyl phthalate, DBP is dibutyl phthalate, BDE209 is decabromodiphenyl ether, DMP is dimethyl phthalate, and DEP is diethyl phthalate. All the PM2.5 samples analyzed proved to be weak toxic for PPT3. The toxicity of PM2.5 was assessed by the dose-addition of organic species and heavy metallic elements existing in PM2.5 with PPT3. The bioluminescence test showed that the metals and organics detected in PM2.5 promoted PM2.5 toxicity. The total detectable organics (denoted by ΣOrs) exhibited slightly higher toxicity than the total metals (denoted by ΣMs). In contrast, the sum of water-soluble ions (denoted by ΣIons) was beneficial to PPT3. The PM2.5 toxicity increased as the PM2.5 trapped more organics or metallic elements from the industrial or densely populated urban areas, where the PM2.5 had a high inhibition rate of bioluminescence for PPT3 in contrast to the residential PM2.5 samples, where the minimum inhibition rate was observed. The toxicity of PM2.5 samples varied with the mass concentrations, chemical constituents, and sampling locations. The chemicals in PM2.5, especially organic

  3. Household Cooking with Solid Fuels Contributes to Ambient PM2.5 Air Pollution and the Burden of Disease

    PubMed Central

    Chafe, Zoë A.; Brauer, Michael; Klimont, Zbigniew; Van Dingenen, Rita; Mehta, Sumi; Rao, Shilpa; Riahi, Keywan; Dentener, Frank

    2014-01-01

    Background: Approximately 2.8 billion people cook with solid fuels. Research has focused on the health impacts of indoor exposure to fine particulate pollution. Here, for the 2010 Global Burden of Disease project (GBD 2010), we evaluated the impact of household cooking with solid fuels on regional population-weighted ambient PM2.5 (particulate matter ≤ 2.5 μm) pollution (APM2.5). Objectives: We estimated the proportion and concentrations of APM2.5 attributable to household cooking with solid fuels (PM2.5-cook) for the years 1990, 2005, and 2010 in 170 countries, and associated ill health. Methods: We used an energy supply–driven emissions model (GAINS; Greenhouse Gas and Air Pollution Interactions and Synergies) and source-receptor model (TM5-FASST) to estimate the proportion of APM2.5 produced by households and the proportion of household PM2.5 emissions from cooking with solid fuels. We estimated health effects using GBD 2010 data on ill health from APM2.5 exposure. Results: In 2010, household cooking with solid fuels accounted for 12% of APM2.5 globally, varying from 0% of APM2.5 in five higher-income regions to 37% (2.8 μg/m3 of 6.9 μg/m3 total) in southern sub-Saharan Africa. PM2.5-cook constituted > 10% of APM2.5 in seven regions housing 4.4 billion people. South Asia showed the highest regional concentration of APM2.5 from household cooking (8.6 μg/m3). On the basis of GBD 2010, we estimate that exposure to APM2.5 from cooking with solid fuels caused the loss of 370,000 lives and 9.9 million disability-adjusted life years globally in 2010. Conclusions: PM2.5 emissions from household cooking constitute an important portion of APM2.5 concentrations in many places, including India and China. Efforts to improve ambient air quality will be hindered if household cooking conditions are not addressed. Citation: Chafe ZA, Brauer M, Klimont Z, Van Dingenen R, Mehta S, Rao S, Riahi K, Dentener F, Smith KR. 2014. Household cooking with solid fuels contributes to

  4. A green approach towards adoption of chemical reaction model on 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane decomposition by differential isoconversional kinetic analysis.

    PubMed

    Das, Mitali; Shu, Chi-Min

    2016-01-15

    This study investigated the thermal degradation products of 2,5-dimethyl-2,5-di-(tert-butylperoxy) hexane (DBPH), by TG/GC/MS to identify runaway reaction and thermal safety parameters. It also included the determination of time to maximum rate under adiabatic conditions (TMR(ad)) and self-accelerating decomposition temperature obtained through Advanced Kinetics and Technology Solutions. The apparent activation energy (Ea) was calculated from differential isoconversional kinetic analysis method using differential scanning calorimetry experiments. The Ea value obtained by Friedman analysis is in the range of 118.0-149.0 kJ mol(-1). The TMR(ad) was 24.0 h with an apparent onset temperature of 82.4°C. This study has also established an efficient benchmark for a thermal hazard assessment of DBPH that can be applied to assure safer storage conditions.

  5. Chemical speciation of PM2.5 and PM10 in south Phoenix, AZ, USA.

    PubMed

    Upadhyay, Nabin; Clements, Andrea; Fraser, Matthew; Herckes, Pierre

    2011-03-01

    Phoenix, AZ, experiences high particulate matter (PM) episodes, especially in the wintertime. The spatial variation of the PM concentrations and resulting differences in exposure is of particular concern. In this study, PM2.s (PM with aerodynamic diameter <2.5 microm) and PM10 (PM with aerodynamic diameter <10 microm) samples were collected simultaneously from the east and west sides of South Phoenix and at a control site in Tempe and analyzed for trace elements and bulk elemental and organic carbon. Measurements showed that although PM2.5 concentrations had similar trends in temporal scale across all sites, concentrations of PM10 did not. The difference in PM10 concentrations and fluctuation across the three sites suggest effects of a local soil source as evidenced by high concentrations of Al, Ca, and Fe in PM10. K and anthropogenic elements (e.g., Cu, Pb, and Zn) in PM2.5 samples on January 1 were strikingly high, suggesting the influence of New Year's fireworks. Concentrations of toxic elements (e.g., Pb) in the study presented here are not different from similar studies in other U.S. cities. Application of principal component analysis indicated two broad categories of emission sources--soil and combustion--together accounting for 80 and 90% of variance, respectively, in PM2.5 and PM10. The soil and combustion components explained approximately 60 and 30% of the variance in PM10, respectively, whereas combustion sources dominated PM2.5 (>50% variance). Many elements associated with anthropogenic sources were highly enriched, with enrichment factors in PM2.5 an order of magnitude higher than in PM10 relative to surface soil composition in the study area.

  6. [Emission characteristics of PM2.5 from blast furnace iron making].

    PubMed

    Fan, Zhen-zhen; Zhao, Ya-li; Zhao, Hao-ning; Liang, Xing-yin; Sun, Jing-wen; Wang, Bao-gui; Wang, Ya-jun

    2014-09-01

    Electrical low pressure impactor (ELPI) was used to online analyze the PM2.5 particle size and mass concentration distribution in the trapping field and ore tank of blast furnace iron-making plant. Results showed that the grain number concentration of PM2.5 in trapping field after dust removal was in the range of 10(5)-10(6)cm-3 , and the particle size was mainly below 0. 1 μm. While the grain number concentration of the PM2.5 in ore tank after dust removal was in the range of 10(4)-10(5) cm-3, the particle size was mainly below 1.0 μm, and the mass concentration distribution showed a single peak. The micro-morphology of PM2.5 monomer was mainly divided into two categories, spherical particles and irregular aggregates. Chemical composition analysis indicated that the concentrations of water soluble SO(2-)(4) , K+ , Ca2+ were higher than other ions in PM2.5, with the percentage of 10. 32% -28.55% , 10. 36% -12. 15% , 3.97% -15. 4% , respectively. The major elements was Fe, Si, Al, with 16. 8% -31. 62% , 2. 24% -8.76% , 1.24% -5. 89% of total mass, respectively; organic carbon and elementary carbon were 2. 7% -4. 6% and 0. 8% -1. 3% , respectively. The emission factors of PM2.5 in trapping field and in ore tank after dust removal were ranged from 0.045 to 0.085 kg t(-1) and 0.042 to 0.071 kg t-1, respectively.

  7. Levels of PM2.5/PM10 and associated metal(loid)s in rural households of Henan Province, China.

    PubMed

    Wu, Fuyong; Wang, Wei; Man, Yu Bon; Chan, Chuen Yu; Liu, Wenxin; Tao, Shu; Wong, Ming Hung

    2015-04-15

    Although a majority of China's rural residents use solid fuels (biomass and coal) for household cooking and heating, clean energy such as electricity and liquid petroleum gas is becoming more popular in the rural area. Unfortunately, both solid fuels and clean energy could result in indoor air pollution. Daily respirable particulate matter (PM≤10 μm) and inhalable particulate matter (PM≤2.5 μm) were investigated in kitchens, sitting rooms and outdoor area in rural Henan during autumn (Sep to Oct 2012) and winter (Jan 2013). The results showed that PM (PM2.5 and PM10) and associated metal(loid)s varied among the two seasons and the four types of domestic energy used. Mean concentrations of PM2.5 and PM10 in kitchens during winter were 59.2-140.4% and 30.5-145.1% higher than those during autumn, respectively. Similar with the trends of PM2.5 and PM10, concentrations of As, Pb, Zn, Cd, Cu, Ni and Mn in household PM2.5 and PM10 were apparently higher in winter than those in autumn. The highest mean concentrations of PM2.5 and PM10 (368.5 and 588.7 μg m(-3)) were recorded in sitting rooms in Baofeng during winter, which were 5.7 and 3.9 times of corresponding health based guidelines for PM2.5 and PM10, respectively. Using coal can result in severe indoor air pollutants including PM and associated metal(loid)s compared with using crop residues, electricity and gas in rural Henan Province. Rural residents' exposure to PM2.5 and PM10 would be roughly reduced by 13.5-22.2% and 8.9-37.7% via replacing coal or crop residues with electricity. The present study suggested that increased use of electricity as domestic energy would effectively improve indoor air quality in rural China.

  8. Trifluoroacetic Acid Level in the Atmosphere of Beijing and Its Relationship with PM2.5

    NASA Astrophysics Data System (ADS)

    Guo, Junyu; Zhang, Jianbo

    2016-04-01

    Atmospheric concentrations of Trifluoroacetic Acid (TFA), one of the main degradation products of HCFC-123, HCFC-124 and HFC-134a, were detected in Beijing, China between 2013 and 2014. By analyzing the 137 atmospheric samples, the results showed that the annual mean atmospheric concentration of TFA was 1459±223 pg•m-3. TFA was mainly distributed in gaseous phase, for the concentration was 1396±225 pg•m-3, while that in particle phase was 62±8 pg•m-3. Considering the frequent occurrence of hazy weather in Beijing, the relationship between TFA and PM2.5 in atmosphere was analyzed. The correlation analysis shows that the proportion of particle phase in atmosphere concentration of TFA and mass concentration of PM2.5 are positively correlated with each other (P<0.001), indicating the particles have an absorption effect on TFA. At the same time, when mass concentration of PM2.5 in atmosphere is high, atmospheric concentration of TFA is relatively low. According to the correlation analysis, mass concentration of PM2.5 and atmospheric concentration of TFA are negatively correlated with each other (P=0.005). The main reason is very likely that particle's extinction for light can be enhanced as particle level rises, which causes TFA precursors photolysis to weaken. The results indicate that PM2.5 has a significant impact on TFA.

  9. Emissions inventory of PM2.5 trace elements across the United States.

    PubMed

    Reff, Adam; Bhave, Prakash V; Simon, Heather; Pace, Thompson G; Pouliot, George A; Mobley, J David; Houyoux, Marc

    2009-08-01

    This paper presents the first National Emissions Inventory (NEI) of fine particulate matter (PM2.5) that includes the full suite of PM2.5 trace elements (atomic number > 10) measured at ambient monitoring sites across the U.S. PM2.5 emissions in the NEI were organized and aggregated into a set of 84 source categories for which chemical speciation profiles are available (e.g., Unpaved Road Dust Agricultural Soil, Wildfires). Emission estimates for ten metals classified as Hazardous Air Pollutants (HAP) were refined using data from a recent HAP NEI. All emissions were spatially gridded, and U.S. emissions maps for dozens of trace elements (e.g., Fe, Ti) are presented for the first time. Nationally, the trace elements emitted in the highest quantities are silicon (3.8 x 10(5) ton/yr), aluminum (1.4 x 10(5) ton/yr), and calcium (1.3 x 10(5) ton/yr). Our chemical characterization of the PM2.5 inventory shows that most of the previously unspeciated emissions are comprised of crustal elements, potassium, sodium, chlorine, and metal-bound oxygen. This work also reveals that the largest PM2.5 sources lacking specific speciation data are off-road diesel-powered mobile equipment, road construction dust, marine vessels, gasoline-powered boats, and railroad locomotives. PMID:19731678

  10. Spatial modeling of PM2.5 concentrations with a multifactoral radial basis function neural network.

    PubMed

    Zou, Bin; Wang, Min; Wan, Neng; Wilson, J Gaines; Fang, Xin; Tang, Yuqi

    2015-07-01

    Accurate measurements of PM2.5 concentration over time and space are especially critical for reducing adverse health outcomes. However, sparsely stationary monitoring sites considerably hinder the ability to effectively characterize observed concentrations. Utilizing data on meteorological and land-related factors, this study introduces a radial basis function (RBF) neural network method for estimating PM2.5 concentrations based on sparse observed inputs. The state of Texas in the USA was selected as the study area. Performance of the RBF models was evaluated by statistic indices including mean square error, mean absolute error, mean relative deviation, and the correlation coefficient. Results show that the annual PM2.5 concentrations estimated by the RBF models with meteorological factors and/or land-related factors were markedly closer to the observed concentrations. RBF models with combined meteorological and land-related factors achieved best performance relative to ones with either type of these factors only. It can be concluded that meteorological factors and land-related factors are useful for articulating the variation of PM2.5 concentration in a given study area. With these covariate factors, the RBF neural network can effectively estimate PM2.5 concentrations with acceptable accuracy under the condition of sparse monitoring stations. The improved accuracy of air concentration estimation would greatly benefit epidemiological and environmental studies in characterizing local air pollution and in helping reduce population exposures for areas with limited availability of air quality data.

  11. Emissions inventory of PM2.5 trace elements across the United States

    SciTech Connect

    Adam Reff; Prakash V. Bhave; Heather Simon; Thompson G. Pace; George A. Pouliot; J. David Mobley; Marc Houyoux

    2009-08-15

    This paper presents the first National Emissions Inventory (NEI) of fine particulate matter (PM2.5) that includes the full suite of PM2.5 trace elements (atomic number >10) measured at ambient monitoring sites across the U.S. PM2.5 emissions in the NEI were organized and aggregated into a set of 84 source categories for which chemical speciation profiles are available (e.g., Unpaved Road Dust, Agricultural Soil, Wildfires). Emission estimates for ten metals classified as Hazardous Air Pollutants (HAP) were refined using data from a recent HAP NEI. All emissions were spatially gridded, and U.S. emissions maps for dozens of trace elements (e.g., Fe, Ti) are presented for the first time. Nationally, the trace elements emitted in the highest quantities are silicon (3.8 x 10{sup 5} ton/yr), aluminium (1.4 x 10{sup 5} ton/yr), and calcium (1.3 x 10{sup 5} ton/yr). Our chemical characterization of the PM2.5 inventory shows that most of the previously unspeciated emissions are comprised of crustal elements, potassium, sodium, chlorine, and metal-bound oxygen. Coal combustion is the largest source of S, Se, Sr, Hg and primary sulfates. This work also reveals that the largest PM2.5 sources lacking specific speciation data are off-road diesel-powered mobile equipment, road construction dust, marine vessels, gasoline-powered boats, and railroad locomotives. 28 refs., 4 figs.

  12. Autoregressive spatially varying coefficients model for predicting daily PM2.5 using VIIRS satellite AOT

    NASA Astrophysics Data System (ADS)

    Schliep, E. M.; Gelfand, A. E.; Holland, D. M.

    2015-12-01

    There is considerable demand for accurate air quality information in human health analyses. The sparsity of ground monitoring stations across the United States motivates the need for advanced statistical models to predict air quality metrics, such as PM2.5, at unobserved sites. Remote sensing technologies have the potential to expand our knowledge of PM2.5 spatial patterns beyond what we can predict from current PM2.5 monitoring networks. Data from satellites have an additional advantage in not requiring extensive emission inventories necessary for most atmospheric models that have been used in earlier data fusion models for air pollution. Statistical models combining monitoring station data with satellite-obtained aerosol optical thickness (AOT), also referred to as aerosol optical depth (AOD), have been proposed in the literature with varying levels of success in predicting PM2.5. The benefit of using AOT is that satellites provide complete gridded spatial coverage. However, the challenges involved with using it in fusion models are (1) the correlation between the two data sources varies both in time and in space, (2) the data sources are temporally and spatially misaligned, and (3) there is extensive missingness in the monitoring data and also in the satellite data due to cloud cover. We propose a hierarchical autoregressive spatially varying coefficients model to jointly model the two data sources, which addresses the foregoing challenges. Additionally, we offer formal model comparison for competing models in terms of model fit and out of sample prediction of PM2.5. The models are applied to daily observations of PM2.5 and AOT in the summer months of 2013 across the conterminous United States. Most notably, during this time period, we find small in-sample improvement incorporating AOT into our autoregressive model but little out-of-sample predictive improvement.

  13. Black Carbon as an Additional Indicator of the Adverse Health Effects of Airborne Particles Compared with PM10 and PM2.5

    PubMed Central

    Hoek, Gerard; Simic-Lawson, Milena; Fischer, Paul; van Bree, Leendert; ten Brink, Harry; Keuken, Menno; Atkinson, Richard W.; Anderson, H. Ross; Brunekreef, Bert; Cassee, Flemming R.

    2011-01-01

    Background: Current air quality standards for particulate matter (PM) use the PM mass concentration [PM with aerodynamic diameters ≤ 10 μm (PM10) or ≤ 2.5 μm (PM2.5)] as a metric. It has been suggested that particles from combustion sources are more relevant to human health than are particles from other sources, but the impact of policies directed at reducing PM from combustion processes is usually relatively small when effects are estimated for a reduction in the total mass concentration. Objectives: We evaluated the value of black carbon particles (BCP) as an additional indicator in air quality management. Methods: We performed a systematic review and meta-analysis of health effects of BCP compared with PM mass based on data from time-series studies and cohort studies that measured both exposures. We compared the potential health benefits of a hypothetical traffic abatement measure, using near-roadway concentration increments of BCP and PM2.5 based on data from prior studies. Results: Estimated health effects of a 1-μg/m3 increase in exposure were greater for BCP than for PM10 or PM2.5, but estimated effects of an interquartile range increase were similar. Two-pollutant models in time-series studies suggested that the effect of BCP was more robust than the effect of PM mass. The estimated increase in life expectancy associated with a hypothetical traffic abatement measure was four to nine times higher when expressed in BCP compared with an equivalent change in PM2.5 mass. Conclusion: BCP is a valuable additional air quality indicator to evaluate the health risks of air quality dominated by primary combustion particles. PMID:21810552

  14. THE RELATIONSHIP BETWEEN REAL-TIME AND TIME-INTEGRATED COARSE (2.5-10MM), INTERMEDIATE (1-2.5MM), AND FINE (<2.5MM) PARTICULATE MATTER IN THE LOS ANGELES BASIN

    EPA Science Inventory

    Population exposure to ambient particulate matter (PM) has received considerable attention due to the association between ambient particulate concentrations and mortality. Current toxicological and epidemiological studies and controlled human and animal exposures suggest that a...

  15. Orbital-optimized MP2.5 and its analytic gradients: Approaching CCSD(T) quality for noncovalent interactions

    SciTech Connect

    Bozkaya, Uğur; Sherrill, C. David

    2014-11-28

    Orbital-optimized MP2.5 [or simply “optimized MP2.5,” OMP2.5, for short] and its analytic energy gradients are presented. The cost of the presented method is as much as that of coupled-cluster singles and doubles (CCSD) [O(N{sup 6}) scaling] for energy computations. However, for analytic gradient computations the OMP2.5 method is only half as expensive as CCSD because there is no need to solve λ{sub 2}-amplitude equations for OMP2.5. The performance of the OMP2.5 method is compared with that of the standard second-order Møller–Plesset perturbation theory (MP2), MP2.5, CCSD, and coupled-cluster singles and doubles with perturbative triples (CCSD(T)) methods for equilibrium geometries, hydrogen transfer reactions between radicals, and noncovalent interactions. For bond lengths of both closed and open-shell molecules, the OMP2.5 method improves upon MP2.5 and CCSD by 38%–43% and 31%–28%, respectively, with Dunning's cc-pCVQZ basis set. For complete basis set (CBS) predictions of hydrogen transfer reaction energies, the OMP2.5 method exhibits a substantially better performance than MP2.5, providing a mean absolute error of 1.1 kcal mol{sup −1}, which is more than 10 times lower than that of MP2.5 (11.8 kcal mol{sup −1}), and comparing to MP2 (14.6 kcal mol{sup −1}) there is a more than 12-fold reduction in errors. For noncovalent interaction energies (at CBS limits), the OMP2.5 method maintains the very good performance of MP2.5 for closed-shell systems, and for open-shell systems it significantly outperforms MP2.5 and CCSD, and approaches CCSD(T) quality. The MP2.5 errors decrease by a factor of 5 when the optimized orbitals are used for open-shell noncovalent interactions, and comparing to CCSD there is a more than 3-fold reduction in errors. Overall, the present application results indicate that the OMP2.5 method is very promising for open-shell noncovalent interactions and other chemical systems with difficult electronic structures.

  16. AMBIENT PM2.5 SAMPLING AND ANALYSIS

    SciTech Connect

    Unknown

    2000-10-01

    This report summarizes observations and tentative conclusions drawn from evaluations of the data captured to date from the operation of the ambient PM{sub 2.5} speciation sites in a geographical area encompassing southeastern Ohio, western Pennsylvania, and northwestern West Virginia. The overall goal of this program, called the Upper Ohio River Valley Project (UORVP), is to better understand the relationship between coal-based power system emissions and ambient air quality in the upper Ohio River Valley region through the collection of chemically resolved or speciated data.

  17. On relationship between aerosols and PM2.5

    NASA Astrophysics Data System (ADS)

    Sano, Itaru; Mukai, Sonoyo; Nakata, Makiko

    2015-04-01

    Since aerosol optical thickness (AOT) is a key parameter of aerosols and description of the Earth's radiation budget, it is widely measured from ground sun photometer network NASA/AERONET [Holben et al., 1998] and from satellite. Fine and surface level aerosol particle called PM2.5, whose diameter is 2.5 μ m or less, is a well-known parameter for understanding polluted level of air. Smirnov et al. reported a good agreement between ground based AERONET AOT (870 nm) and dust concentrations at Barbados [Smirnov et al., 2000]. Wang and Christopher founded a good correlation between satellite based MODIS AOT product and PM2.5 in Alabama area [Wang and 2003]. Long range transported dusts, particularly Asian dust events, are easy to change the vertical profile of aerosol extinction. The vertical profile is important to estimate PM information because both AOT information measured from ground or satellite are integrated value of aerosol extinction from ground to space, i.e. columnar AOT. Thus, we have also proposed correlations between ground level PM2.5 and AERONET AOT (670 nm) in two cases of ordinary air condition and dusty days [Sano et al., 2010]. In this work, we investigate the relationship between PM2.5 and AERONET AOT considering LIDAR measurements. Note that all of instruments are set up at the roof of the University building (50 m) and collocated in 10 m area. Surface-level AOT is derived from AERONET AOT multiplied by an averaged vertical aerosol extinction given by LIDAR. Note that the definition of surface-level AOT in this work is assumed as AOT up to 500 m height. Introduction of surface-level AOT enables to avoid the contamination of dusty aerosol signal existing at high altitude from columnar AOT. The cloud aerosol imager (CAI) on GOSAT satellite has four observing wavelengths, 380, 670, 870 nm, and 1.6 μ m. In this work three channels are selected to estimate aerosol information. Look-up table (LUT) method is applied to estimate the optical properties

  18. Premature mortality in India due to PM2.5 and ozone exposure

    NASA Astrophysics Data System (ADS)

    Ghude, Sachin D.; Chate, D. M.; Jena, C.; Beig, G.; Kumar, R.; Barth, M. C.; Pfister, G. G.; Fadnavis, S.; Pithani, Prakash

    2016-05-01

    This bottom-up modeling study, supported by new population census 2011 data, simulates ozone (O3) and fine particulate matter (PM2.5) exposure on local to regional scales. It quantifies, present-day premature mortalities associated with the exposure to near-surface PM2.5 and O3 concentrations in India using a regional chemistry model. We estimate that PM2.5 exposure leads to about 570,000 (CI95: 320,000-730,000) premature mortalities in 2011. On a national scale, our estimate of mortality by chronic obstructive pulmonary disease (COPD) due to O3 exposure is about 12,000 people. The Indo-Gangetic region accounts for a large part (~42%) of the estimated mortalities. The associated lost life expectancy is calculated as 3.4 ± 1.1 years for all of India with highest values found for Delhi (6.3 ± 2.2 years). The economic cost of estimated premature mortalities associated with PM2.5 and O3 exposure is about 640 (350-800) billion USD in 2011, which is a factor of 10 higher than total expenditure on health by public and private expenditure.

  19. Portable Life Support System 2.5 Fan Design and Development

    NASA Technical Reports Server (NTRS)

    Quinn, Gregory; Carra, Michael; Converse, David; Chullen, Cinda

    2016-01-01

    NASA is building a high-fidelity prototype of an advanced Portable Life Support System (PLSS) as part of the Advanced Exploration Systems Program. This new PLSS, designated as PLSS 2.5, will advance component technologies and systems knowledge to inform a future flight program. The oxygen ventilation loop of its predecessor, PLSS 2.0, was driven by a centrifugal fan developed using specifications from the Constellation Program. PLSS technology and system parameters have matured to the point where the existing fan will not perform adequately for the new prototype. In addition, areas of potential improvement were identified with the PLSS 2.0 fan that could be addressed in a new design. As a result, a new fan was designed and tested for the PLSS 2.5. The PLSS 2.5 fan is a derivative of the one used in PLSS 2.0, and it uses the same nonmetallic, canned motor, with a larger volute and impeller to meet the higher pressure drop requirements of the PLSS 2.5 ventilation loop. The larger impeller allows it to operate at rotational speeds that are matched to rolling element bearings, and which create reasonably low impeller tip speeds consistent with prior, oxygen-rated fans. Development of the fan also considered a shrouded impeller design that could allow larger clearances for greater oxygen safety, assembly tolerances and particle ingestion. This paper discusses the design, manufacturing and performance testing of the new fans.

  20. Timing is everything: neural response dynamics during syllable processing and its relation to higher-order cognition in schizophrenia and healthy comparison subjects.

    PubMed

    Dale, Corby L; Findlay, Anne M; Adcock, R Alison; Vertinski, Mary; Fisher, Melissa; Genevsky, Alexander; Aldebot, Stephanie; Subramaniam, Karuna; Luks, Tracy L; Simpson, Gregory V; Nagarajan, Srikantan S; Vinogradov, Sophia

    2010-02-01

    Successful linguistic processing requires efficient encoding of successively-occurring auditory input in a time-constrained manner, especially under noisy conditions. In this study we examined the early neural response dynamics to rapidly-presented successive syllables in schizophrenia participants and healthy comparison subjects, and investigated the effects of noise on these responses. We used magnetoencephalography (MEG) to reveal the time-course of stimulus-locked activity over bilateral auditory cortices during discrimination of syllable pairs that differed either in voice onset time (VOT) or place of articulation (POA), in the presence or absence of noise. We also examined the association of these early neural response patterns to higher-order cognitive functions. The M100 response, arising from auditory cortex and its immediate environs, showed less attenuation to the second syllable in patients with schizophrenia than healthy comparison subjects during VOT-based discrimination in noise. M100 response amplitudes were similar between groups for the first syllable during all three discrimination conditions, and for the second syllable during VOT-based discrimination in quiet and POA-based discrimination in noise. Across subjects, the lack of M100 attenuation to the second syllable during VOT-based discrimination in noise was associated with poorer task accuracy, lower education and IQ, and lower scores on measures of Verbal Learning and Memory and Global Cognition. Because the neural response to the first syllable was not significantly different between groups, nor was a schizophrenia-related difference obtained in all discrimination tasks, early linguistic processing dysfunction in schizophrenia does not appear to be due to general sensory input problems. Rather, data suggest that faulty temporal integration occurs during successive syllable processing when the signal-to-noise ratio is low. Further, the neural mechanism by which the second syllable is

  1. Timing is everything: Neural response dynamics during syllable processing and its relation to higher-order cognition in schizophrenia and healthy comparison subjects

    PubMed Central

    Dale, Corby L.; Findlay, Anne M.; Adcock, R. Alison; Vertinski, Mary; Fisher, Melissa; Genevsky, Alexander; Aldebot, Stephanie; Subramaniam, Karuna; Luks, Tracy L.; Simpson, Gregory V.; Nagarajan, Srikantan S.; Vinogradov, Sophia

    2009-01-01

    Successful linguistic processing requires efficient encoding of successively-occurring auditory input in a time-constrained manner, especially under noisy conditions. In this study we examined the early neural response dynamics to rapidly-presented successive syllables in schizophrenia participants and healthy comparison subjects, and investigated the effects of noise on these responses. We used magnetoencephalography (MEG) to reveal the time-course of stimulus-locked activity over bilateral auditory cortices during discrimination of syllable pairs that differed either in voice onset time (VOT) or place of articulation (POA), in the presence or absence of noise. We also examined the association of these early neural response patterns to higher-order cognitive functions. The M100 response, arising from auditory cortex and its immediate environs, showed less attenuation to the second syllable in patients with schizophrenia than healthy comparison subjects during VOT-based discrimination in noise. M100 response amplitudes were similar between groups for the first syllable during all three discrimination conditions, and for the second syllable during VOT-based discrimination in quiet and POA-based discrimination in noise. Across subjects, the lack of M100 attenuation to the second syllable during VOT-based discrimination in noise was associated with poorer task accuracy, lower education and IQ, and lower scores on measures of Verbal Learning and Memory and Global Cognition. Because the neural response to the first syllable was not significantly different between groups, nor was a schizophrenia-related difference obtained in all discrimination tasks, early linguistic processing dysfunction in schizophrenia does not appear to be due to general sensory input problems. Rather, data suggest that faulty temporal integration occurs during successive syllable processing when the signal-to-noise ratio is low. Further, the neural mechanism by which the second syllable is

  2. Daily Estimation of Ground-Level PM2.5 Concentrations over Beijing Using 3 km Resolution MODIS AOD.

    PubMed

    Xie, Yuanyu; Wang, Yuxuan; Zhang, Kai; Dong, Wenhao; Lv, Baolei; Bai, Yuqi

    2015-10-20

    Estimating exposures to PM2.5 within urban areas requires surface PM2.5 concentrations at high temporal and spatial resolutions. We developed a mixed effects model to derive daily estimations of surface PM2.5 levels in Beijing, using the 3 km resolution satellite aerosol optical depth (AOD) calibrated daily by the newly available high-density surface measurements. The mixed effects model accounts for daily variations of AOD-PM2.5 relationships and shows good performance in model predictions (R(2) of 0.81-0.83) and cross-validations (R(2) of 0.75-0.79). Satellite derived population-weighted mean PM2.5 for Beijing was 51.2 μg/m(3) over the study period (Mar 2013 to Apr 2014), 46% higher than China's annual-mean PM2.5 standard of 35 μg/m(3). We estimated that more than 19.2 million people (98% of Beijing's population) are exposed to harmful level of long-term PM2.5 pollution. During 25% of the days with model data, the population-weighted mean PM2.5 exceeded China's daily PM2.5 standard of 75 μg/m(3). Predicted high-resolution daily PM2.5 maps are useful to identify pollution "hot spots" and estimate short- and long-term exposure. We further demonstrated that a good calibration of the satellite data requires a relatively large number of ground-level PM2.5 monitoring sites and more are still needed in Beijing. PMID:26310776

  3. Assessment of Population and Microenvironmental Exposure to Fine Particulate Matter (PM2.5)

    NASA Astrophysics Data System (ADS)

    Jiao, Wan

    A positive relationship exists between fine particulate matter (PM 2.5) exposure and adverse health effects. PM2.5 concentration-response functions used in the quantitative risk assessment were based on findings from human epidemiological studies that relied on areawide ambient concentrations as surrogate for actual ambient exposure, which cannot capture the spatial and temporal variability in human exposures. The goal of the study is to assess inter-individual, geographic and seasonal variability in population exposures to inform the interpretation of available epidemiological studies, and to improve the understanding of how exposure-related factors in important exposure microenvironments contribute to the variability in individual PM2.5 exposure. Typically, the largest percentage of time in which an individual is exposed to PM2.5 of ambient origin occurs in indoor residence, and the highest ambient PM2.5 concentrations occur in transportation microenvironments because of the proximity to on-road traffic emissions. Therefore, indoor residence and traffic-related transportation microenvironments were selected for further assessment in the study. Population distributions of individual daily PM2.5 exposures were estimated for the selected regions and seasons using the Stochastic Human Exposure and Dose Simulation Model for Particulate Matter (SHEDS-PM). For the indoor residence, the current practice by assuming the entire residence to be one large single zone for calculating the indoor residential PM 2.5 concentration was evaluated by applying an indoor air quality model, RISK, to compare indoor PM2.5 concentrations between single-zone and multi-zone scenarios. For the transportation microenvironments, one field data collection focused on in-vehicle microenvironment and was conducted to quantify the variability in the in-vehicle PM2.5 concentration with respect to the outside vehicle concentration for a wide range of conditions that affect intra-vehicle variability

  4. A 2.5 GS/s 14-bit D/A converter with 8 to 1 MUX

    NASA Astrophysics Data System (ADS)

    Jun'an, Zhang; Guangjun, Li; Ruitao, Zhang; Dongbing, Fu; Jiaoxue, Li; Yafeng, Wei; Bo, Yan; Jun, Liu; Ruzhang, Li

    2016-03-01

    A 2.5 GS/s 14-bit D/A converter (DAC) with 8 to 1 MUX is presented. This 14-bit DAC uses a “5+9” segment PMOS current-steering architecture. A bias circuit which ensures the PMOS current source obtains a larger output impedance under every PVT (process, source voltage and temperature) corner is also presented. The 8 to 1 MUX has a 3 stage structure, and a proper timing sequence is designed to ensure reliable data synthesis. A DEM function which is merged with a “5-31” decoder is used to improve the DAC's dynamic performance. This DAC is embedded in a 2.5 GHz direct digital frequency synthesizer (DDS) chip, and is implemented in a 0.18 μm CMOS technology, occupies 4.86 × 2. 28 mm2 including bond pads (DAC only), and the measured performance is SFDR > 40 dB (with and without DEM) for output signal frequency up to 1 GHz. Compared with other present published DACs with a non-analog-resample structure (means return-to-zero or quad-switch structure is unutilized), this paper DAC's clock frequency (2.5 GHz) and higher output frequency SFDR (> 40 dB, up to 1 GHz) has some competition. Project supported by the National Natural Science Foundation of China (Nos. 61006027, 61176030), the Research Foundation of Key Laboratory of Analog Integrated Circuit (Nos. 9140C0902120C09034, 9140c090204130c09042), and the Fundamental Research Funds for the Central Universities of China (No. ZYGX2012J003).

  5. Reactivity of 1,2,5,6-Tetrathiocines

    NASA Astrophysics Data System (ADS)

    Wrixon, Justin D.

    This thesis describes selected chemistry of 1,2,5,6-tetrathiocines, 8-membered heterocycles containing four S atoms which can be considered as bis(disulfides). Chapter 1 provides a literature review of the existing chemistry of 1,2,5,6-tetrathiocines. Chapters 2 -- 4 examine the oxidative addition chemistry of tetrathiocines to zero-valent group 10 metal complexes in the presence of an auxiliary phosphine ligand under microwave conditions to afford nickel, palladium and platinum dithiolate complexes. These chapters probe the effect of the metal (Chapter 2), the auxiliary phosphine (Chapter 3) and the tetrathiocine (Chapter 4) on the outcome of the chemical reaction, leading to a range of mono-, di- and hexa-metallic complexes which have been fully characterized by multinuclear NMR, mass spectroscopy and X-ray diffraction. Finally, Chapter 6 describes the use of tetrathiocines as precursors to 1,3,2-benzodithiazyl (BDTA) radicals and two new dithiazolyl radicals have been isolated and characterized by X-ray diffraction and EPR spectroscopy.

  6. ADVANCES IN CONTROL OF PM2..5 AND PM2..5 PRECURSORS GENERATED BY THE COMBUSTION OF PULVERIZED COAL

    EPA Science Inventory

    Particulate matter smaller than 2.5 micrometers in aerodynamic diameter (PM2.5) is of concern due to adverse health effects associated with elevated ambient mass concentrations of PM2.5. PM2.5 from coal-fired utility boilers is composed of directly emitted (primary) particles and...

  7. [Characterization of organic carbon (OC) and elemental carbon (EC) in PM2.5 during the winter in three major cities in Fujian province, China].

    PubMed

    Chen, Yan-ting; Chen, Jin-sheng; Hu, Gong-ren; Xu, Ling-ling; Yin, Li-qian; Zhang, Fu-wang

    2013-05-01

    PM2.5 samples were collected in three cities (Fuzhou, Xiamen and Quanzhou) in Fujian Province, China, during the winter, and were analyzed for organic carbon (OC) and elemental carbon (EC) by thermal optical transmission (TOT). The characteristics such as pollution levels and spatial distributions of PM2.5, OC and EC, correlations between OC and EC, OC/EC ratios and secondary organic carbon (SOC) were discussed in details. Average concentrations of PM2.5 were ranged from (79.94 +/- 18.08) microg(-3) to (114.78 +/- 26.10) microg x m(-3), which were in excess of the Ambient Air Quality Standards (GB 3095-2012) 24-hr mass-based standards of 75 microg x m(-3). Averages concentrations of OC and EC were fluctuated from (14.77 +/- 2.65) microg x m(-3) to (19.27 +/- 1.96) microg x m(-3) and (1.99 +/- 0.50) microg x m(-3) to (3.36 +/- 0.41) microg x m(-3), respectively, which were 1.2 to 1.6 times and 1.2 to 2.0 times more than that in the background site, Pingtan in Fuzhou. Correlations between OC and EC in PM2.5 were found to be strong in Pingtan (R2 = 0.70) and Jin'an (R2 = 0.66) (Fuzhou) , suggesting that there were similar primary pollutants of OC and EC. Average OC/EC ratios were 5.64-7.71 and all higher than 2, which indicated that the secondary organic carbon (SOC) was formed. The estimated concentrations of SOC were from 2.47 microg x m3 to 7.17 microg x m(-3), which contributed 13.08%-45.67% to the OC and 2.20%-7.78% to PM2.5.

  8. Anthropogenic and biogenic organic compounds in summertime fine aerosols (PM2.5) in Beijing, China

    NASA Astrophysics Data System (ADS)

    Yang, Fan; Kawamura, Kimitaka; Chen, Jing; Ho, Kinfai; Lee, Shuncheng; Gao, Yuan; Cui, Long; Wang, Tieguan; Fu, Pingqing

    2016-01-01

    Ambient fine aerosol samples (PM2.5) were collected at an urban site (PKU) in Beijing and its upwind suburban site (Yufa) during the CAREBEIJING-2007 field campaign. Organic molecular compositions of the PM2.5 samples were studied for seven organic compound classes (sugars, lignin/resin acids, hydroxy-/polyacids, aromatic acids, biogenic SOA tracers, fatty acids and phthalates) using capillary GC/MS to better understand the characteristics and sources of organic aerosol pollution in Beijing. More than 60 individual organic species were detected in PM2.5 and were grouped into different compound classes based on their functional groups. Concentrations of total quantified organics at Yufa (469-1410 ng m-3, average 1050 ng m-3) were slightly higher than those at PKU (523-1390 ng m-3, 900 ng m-3). At both sites, phthalates were found as the most abundant compound class. Using a tracer-based method, the contributions of the biogenic secondary organic carbon (SOC) to organic carbon (OC) were 3.1% at PKU and 5.5% at Yufa, among which isoprene-SOC was the dominant contributor. In addition, most of the measured organic compounds were higher at Yufa than those at PKU, indicating a more serious pollution in its upwind region than in urban Beijing.

  9. Air Pollution Exposure Model for Individuals (EMI) in Health Studies: Evaluation for Ambient PM2.5 in Central North Carolina

    EPA Science Inventory

    Air pollution health studies of fine particulate matter (diameter ≤2.5 μm, PM2.5) often use outdoor concentrations as exposure surrogates. Failure to account for variability of indoor infiltration of ambient PM2.5 and time indoors can induce exposure errors. We developed an...

  10. Source identification of PM 2.5 particles measured in Gwangju, Korea

    NASA Astrophysics Data System (ADS)

    Lee, Hanlim; Park, Seung S.; Kim, Kyung W.; Kim, Young J.

    diesel traffic exhaust (47.0%) in stagnant conditions (S) was much higher than the average contribution of diesel vehicle exhaust (33.4%) during the sampling period. During Asian dust (AD) periods when the air mass passed over the Korean peninsula, Asian dust and secondary organic carbon accounted for 25.2 and 23.0% of the PM 2.5 mass, respectively, whereas Asian dust contributed only 10.8% to the PM 2.5 mass during the AD event when the air mass passed over the Yellow Sea. The contribution of biomass burning to the PM 2.5 mass during the biomass burning (BB) event equaled 63.8%.

  11. [Characterising seasonal variation and spatial distribution of PM2.5 species in Shenzhen].

    PubMed

    Yun, Hui; He, Ling-Yan; Huang, Xiao-Feng; Lan, Zi-Juan; Li, Xiang; Zeng, Li-Wu

    2013-04-01

    To investigate the effect of meteorological characteristics on PM2.5 chemical composition and the spatial distribution of different PM2.5 species in Shenzhen, 24-h PM2.5 samples were collected every six days from December 2008 to December 2009. The sampling network included an industrial site at Baoan, an urban site at Luohu and a seaside site at Yantian. Water-soluble inorganic ions and carbonaceous material (organic carbon and elemental carbon) were analyzed. The industrial site showed a much higher concentration than that of other two sites of organic matter, elemental carbon and nitrate, which presented the obvious difference of local emissions. But for the concentration of sulfate and ammonium of three different sites nearly stayed at the same level and indicated that they were mainly influenced by regional transport. OC/EC had the characteristics of the industrial site < the urban site < the seaside site, which implied that the industrial site had less secondary organic matter and more primary pollution sources. As the subtropical maritime monsoon climate is the dominant meteorological feature of the Pearl River Delta with a southwesterly transport and abundant rain in spring and summer, in contrast to a northwesterly transport and little rain in fall and winter, the PM2.5 pollution was much more serious in winter than in summer. Compared with the results of the similar experiment in 2004, the concentration of sulfate in PM2.5 has significantly declined because of the measures of reducing the emission of sulfer dioxide. But the pollution of vehicle emissions has become significant.

  12. Comparison between 2.5D and 3D simulations of coronal mass ejections

    NASA Astrophysics Data System (ADS)

    Jacobs, C.; van der Holst, B.; Poedts, S.

    2007-07-01

    Context: The shocks and magnetic clouds related to Coronal Mass Ejections (CMEs) in the solar corona and interplanetary space (IP) play an important role in the study of space weather. In order to study the evolution of these IP shocks, numerical simulations of a simplified CME model were performed. Aims: In an earlier study, the effect of the background wind on the evolution of interplanetary shock waves was investigated, where the computations were carried out under the assumption of axial symmetry. The assumption of axial symmetry might be a good approach for the solar corona under conditions of solar minimum, but for the study of CMEs this assumption is definitely no longer valid as CMEs possess clearly a fully three dimensional (3D) structure. From this perspective, the previous simulations were repeated, but now in a three dimensional set-up in order to point out the differences between the 2.5D and 3D simulations and to check the quality and reliability of the 2.5D simulations. Methods: The computations were performed in the framework of ideal magnetohydrodynamics (MHD) and to advance the ideal MHD equations in time a parallel finite volume code with explicit upwind solver was used. The shock waves are generated in a similar way in both the 3D and 2.5D simulations, namely by a simple density-blob model. The 3D and 2.5D simulations are all performed with the same numerical methods and on comparable grids, such that the differences between the simulations are purely due to the dimensionality of the problem, and/or the initial parameters for the CME generation. Results: Three different axisymmetric simulations of CME propagation are compared with the fully three dimensional computation. The 2.5D simulations differ from each other in the parameters used for CME initiation. In a first simulation, the same initial parameters as for the 3D case were taken, in a second simulation the initial amount of mass in the 2.5D and 3D CME was the same, and in a third

  13. AMBIENT PM2.5 SAMPLING AND ANALYSIS

    SciTech Connect

    Unknown

    2001-04-30

    This is the third semi-annual technical progress report summarizing observations and tentative conclusions drawn from evaluations of the data captured to date from the operation of the ambient PM{sub 2.5} speciation sites in a geographical area encompassing southeastern Ohio, western Pennsylvania, and northwestern West Virginia. The overall goal of this program, called the Upper Ohio River Valley Project (UORVP), is to better understand the relationship between coal-based power system emissions and ambient air quality in the upper Ohio River Valley region through the collection of chemically resolved or speciated data. In order to provide a ''stand alone'' document, this report contains updated versions of Section 1 (Introduction) and Section 2 (Experimental) in their entirety from the first report.

  14. A compact 2.5-Kelvin closed-cycle refrigerator

    NASA Astrophysics Data System (ADS)

    Britcliffe, Mike

    A helium refrigerator utilizing the Gifford-McMahon/Joule-Thomson cycle was designed and tested to demonstrate the feasibility of using small closed-cycle refrigerators as an alternative to batch filled-cryostats for operating temperatures below 4 K. The systems could be used to cool low-noise microwave maser amplifiers located in large parabolic antennas. These antennas tilt vertically, making conventional liquid-filled dewars difficult to use. The system could also be used for a nontilting beam waveguide antenna to reduce the helium consumption of a liquid helium cryostat. The prototype system is adjustable to provide 700 milliwatts of cooling at 2.5 K to 3 watts at 4.3 K. The performance of the unit is not significantly affected by operation in any physical orientation.

  15. Asymmetric transformations of achiral 2,5-cyclohexadienones

    PubMed Central

    Kalstabakken, Kyle A.; Harned, Andrew M.

    2014-01-01

    Cyclohexadienones are versatile platforms for performing asymmetric synthesis as evidenced by the numerous natural product syntheses that exploit their diverse reactivity profile. However, there are few general methods available for the direct asymmetric synthesis of chiral cyclohexadienones. To circumvent this problem, several researchers have developed catalytic asymmetric methods that employ readily available achiral 2,5-cyclohexadienones as substrates. Many of these reactions are desymmetrizations in which one of the enantiotopic alkenes of an achiral dienone is transformed. Others involve selective reaction at one alkene of an unsymmetrically substituted, achiral dienone. This review will cover advances in this area over the last 20 years and the application of these strategies in complex molecule synthesis. PMID:26688596

  16. An empirical relationship between PM(2.5) and aerosol optical depth in Delhi Metropolitan.

    PubMed

    Kumar, Naresh; Chu, Allen; Foster, Andrew

    2007-07-01

    Atmospheric remote sensing offers a unique opportunity to compute indirect estimates of air quality, which are critically important for the management and surveillance of air quality in megacities of developing countries, particularly in India and China, which have experienced elevated concentration of air pollution but lack adequate spatial-temporal coverage of air pollution monitoring. This article examines the relationship between aerosol optical depth (AOD) estimated from satellite data at 5 km spatial resolution and the mass of fine particles ≤2.5 μm in aerodynamic diameter (PM(2.5)) monitored on the ground in Delhi Metropolitan where a series of environmental laws have been instituted in recent years.PM(2.5) monitored at 113 sites were collocated by time and space with the AOD computed using the data from Moderate Resolution Imaging Spectroradiometer (MODIS onboard the Terra satellite). MODIS data were acquired from NASA's Goddard Space Flight Center Earth Sciences Distributed Active Archive Center (DAAC). Our analysis shows a significant positive association between AOD and PM(2.5). After controlling for weather conditions, a 1% change in AOD explains 0.52±0.202% and 0.39±0.15% change in PM(2.5) monitored within ±45 and 150 min intervals of AOD data. This relationship will be used to estimate air quality surface for previous years, which will allow us to examine the time-space dynamics of air pollution in Delhi following recent air quality regulations, and to assess exposure to air pollution before and after the regulations and its impact on health.

  17. Characterization and Cytotoxicity of PM<0.2, PM0.2–2.5 and PM2.5–10 around MSWI in Shanghai, China

    PubMed Central

    Cao, Lingling; Zeng, Jianrong; Liu, Ke; Bao, Liangman; Li, Yan

    2015-01-01

    Background: The potential impact of municipal solid waste incineration (MSWI), which is an anthropogenic source of aerosol emissions, is of great public health concern. This study investigated the characterization and cytotoxic effects of ambient ultrafine particles (PM<0.2), fine particles (PM0.2–2.5) and coarse particles (PM2.5–10) collected around a municipal solid waste incineration (MSWI) plant in the Pudong district of Shanghai. Methods: Mass concentrations of trace elements in particulate matter (PM) samples were determined using ICP-MS (Inductively Coupled Plasma Mass Spectrometry). The cytotoxicity of sampled atmospheric PM was evaluated by cell viability and reactive oxygen species (ROS) levels in A549 cells. Result: The mass percentage of PM0.2–2.5 accounted for 72.91% of the total mass of PM. Crustal metals (Mg, Al, and Ti) were abundant in the coarse particles, while the anthropogenic elements (V, Ni, Cu, Zn, Cd, and Pb) were dominant in the fine particles. The enrichment factors of Zn, Cd and Pb in the fine and ultrafine particles were extremely high (>100). The cytotoxicity of the size-resolved particles was in the order of coarse particles < fine particles < ultrafine particles. Conclusions: Fine particles dominated the MSWI ambient particles. Emissions from the MSWI could bring contamination of anthropogenic elements (Zn, Cd and Pb) into ambient environment. The PM around the MSWI plant displayed an additive toxic effect, and the ultrafine and fine particles possessed higher biological toxicity than the coarse particles. PMID:25985309

  18. Association of cardiac and vascular changes with ambient PM2.5 in diabetic individuals

    PubMed Central

    2010-01-01

    Background and Objective Exposure to fine airborne particles (PM2.5) has been shown to be responsible for cardiovascular and hematological effects, especially in older people with cardiovascular disease. Some epidemiological studies suggest that individuals with diabetes may be a particularly susceptible population. This study examined effects of short-term exposures to ambient PM2.5 on markers of systemic inflammation, coagulation, autonomic control of heart rate, and repolarization in 22 adults (mean age: 61 years) with type 2 diabetes. Methods Each individual was studied for four consecutive days with daily assessments of plasma levels of blood markers. Cardiac rhythm and electrocardiographic parameters were examined at rest and with 24-hour ambulatory ECG monitors. PM2.5 and meteorological data were measured daily on the rooftop of the patient exam site. Data were analyzed with models adjusting for season, weekday, meteorology, and a random intercept. To identify susceptible subgroups, effect modification was analyzed by clinical characteristics associated with insulin resistance as well as with oxidative stress and by medication intake. Results Interleukin (IL)-6 and tumor necrosis factor alpha showed a significant increase with a lag of two days (percent change of mean level: 20.2% with 95%-confidence interval [6.4; 34.1] and 13.1% [1.9; 24.4], respectively) in association with an increase of 10 μg/m3 in PM2.5. Obese participants as well as individuals with elevated glycosylated hemoglobin, lower adiponectin, higher ferritin or with glutathione S-transferase M1 null genotype showed higher IL-6 effects. Changes in repolarization were found immediately as well as up to four days after exposure in individuals without treatment with a beta-adrenergic receptor blocker. Conclusions Exposure to elevated levels of PM2.5 alters ventricular repolarization and thus may increase myocardial vulnerability to arrhythmias. Exposure to PM2.5 also increases systemic

  19. Galaxy Zoo Hubble: Crowdsourced Morphologies for 169,944 Galaxies at 02.5

    NASA Astrophysics Data System (ADS)

    Willett, Kyle; Galloway, Melanie; Fortson, Lucy; Bamford, Steven; Masters, Karen; Lintott, Chris; Simmons, Brooke; Cheung, Edmond; Schawinski, Kevin; Scarlata, Claudia; Beck, Melanie; Galaxy Zoo volunteers

    2016-01-01

    The Galaxy Zoo project uses crowdsourced visual classifications to create large and statistically robust catalogs of detailed galaxy morphology. We present initial results for the Galaxy Zoo: Hubble dataset, which includes 169,944 images of galaxies selected from the AEGIS, COSMOS, GEMS, and GOODS surveys. The galaxies span a redshift range of 02.5, with a median of z≈0.7. The classification scheme distinguishes between bulge-dominated and disk-dominated galaxies, as well as identifying kpc-scale features including galactic bars, spiral arms, irregular structure, and mergers. In addition, we also measure the geometry and relative positions of clumpy structures that are unique to high-redshift star-forming galaxies. Visual classifications are calibrated using a set of z≈0.05 SDSS images that are processed to appear as they would at a variety of simulated redshifts using Hubble; this measures the morphological bias for galaxies as a function of changing the apparent size and brightness, without overcorrecting for effects such as an evolving Lstar. We present a new technique for debiasing the morphologies based on a simple parametric model of surface brightness and distance, which adjusts the threshold for detecting feature or disk-dominated galaxies in fainter galaxies and at higher redshifts. We demonstrate the effectiveness of this technique for bulge/disk separation, and discuss its applications and limitations for smaller physical sub-structures. We also present preliminary results analyzing the evolution of disk sub-structure as a function of cosmic time. All the above data will be included in the upcoming release of the full Galaxy Zoo: Hubble catalog.

  20. The star-formation rates of 1.5 < z < 2.5 massive galaxies

    NASA Astrophysics Data System (ADS)

    Nordon, R.; Lutz, D.; Shao, L.; Magnelli, B.; Berta, S.; Altieri, B.; Andreani, P.; Aussel, H.; Bongiovanni, A.; Cava, A.; Cepa, J.; Cimatti, A.; Daddi, E.; Dominguez, H.; Elbaz, D.; Förster Schreiber, N. M.; Genzel, R.; Grazian, A.; Magdis, G.; Maiolino, R.; Pérez García, A. M.; Poglitsch, A.; Popesso, P.; Pozzi, F.; Riguccini, L.; Rodighiero, G.; Saintonge, A.; Sanchez-Portal, M.; Santini, P.; Sturm, E.; Tacconi, L.; Valtchanov, I.; Wetzstein, M.; Wieprecht, E.

    2010-07-01

    The star formation rate (SFR) is a key parameter in the study of galaxy evolution. The accuracy of SFR measurements at z ~ 2 has been questioned following a disagreement between observations and theoretical models. The latter predict SFRs at this redshift that are typically a factor 4 or more lower than the measurements. We present star-formation rates based on calorimetric measurements of the far-infrared (FIR) luminosities for massive 1.5 < z < 2.5, normal star-forming galaxies (SFGs), which do not depend on extinction corrections and/or extrapolations of spectral energy distributions. The measurements are based on observations in GOODS-N with the Photodetector Array Camera and Spectrometer (PACS) onboard Herschel, as part of the PACS evolutionary probe (PEP) project, that resolve for the first time individual SFGs at these redshifts at FIR wavelengths. We compare FIR-based SFRs to the more commonly used 24 μm and UV SFRs. We find that SFRs from 24 μm alone are higher by a factor of ~4-7.5 than the true SFRs. This overestimation depends on luminosity: gradually increasing for log L(24 μm) > 12.2 L_⊙. The SFGs and AGNs tend to exhibit the same 24 μm excess. The UV SFRs are in closer agreement with the FIR-based SFRs. Using a Calzetti UV extinction correction results in a mean excess of up to 0.3 dex and a scatter of 0.35 dex from the FIR SFRs. The previous UV SFRs are thus confirmed and the mean excess, while narrowing the gap, is insufficient to explain the discrepancy between the observed SFRs and simulation predictions. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  1. Enzymatically active 2',5'-oligoadenylate synthetases are widely distributed among Metazoa, including protostome lineage.

    PubMed

    Päri, Mailis; Kuusksalu, Anne; Lopp, Annika; Kjaer, Karina Hansen; Justesen, Just; Kelve, Merike

    2014-02-01

    2',5'-Oligoadenylate synthetases (OASs) belong to the nucleotidyl transferase family together with poly(A) polymerases, CCA-adding enzymes and the recently discovered cyclic-GMP-AMP synthase (cGAS). Mammalian OASs have been thoroughly characterized as components of the interferon-induced antiviral system. The OAS activity and the respective genes were also discovered in marine sponges where the interferon system is absent. In this study the recombinant OASs from several multicellular animals and their closest unicellular relative, a choanoflagellate, were expressed in a bacterial expression system and their enzymatic activities were examined. We demonstrated 2-5A synthesizing activities of OASs from the marine sponge Tedania ignis, a representative of the phylogenetically oldest metazoan phylum (Porifera), from an invertebrate of the protostome lineage, the mollusk Mytilus californianus (Mollusca), and from a vertebrate species, a cartilaginous fish Leucoraja erinacea (Chordata). However, the expressed proteins from an amphibian, the salamander Ambystoma mexicanum (Chordata), and from a protozoan, the marine choanoflagellate Monosiga brevicollis (Choanozoa), did not show 2-5A synthesizing activity. Differently from other studied OASs, OAS from the marine sponge T. ignis was able to catalyze the formation of oligomers having both 2',5'- and 3',5'-phosphodiester linkages. Our data suggest that OASs from sponges and evolutionarily higher animals have similar activation mechanisms which still include different affinities and possibly different structural requirements for the activating RNAs. Considering their 2'- and 3'-specificities, sponge OASs could represent a link between evolutionarily earlier nucleotidyl transferases and 2'-specific OASs from higher animals.

  2. Enzymatically active 2',5'-oligoadenylate synthetases are widely distributed among Metazoa, including protostome lineage.

    PubMed

    Päri, Mailis; Kuusksalu, Anne; Lopp, Annika; Kjaer, Karina Hansen; Justesen, Just; Kelve, Merike

    2014-02-01

    2',5'-Oligoadenylate synthetases (OASs) belong to the nucleotidyl transferase family together with poly(A) polymerases, CCA-adding enzymes and the recently discovered cyclic-GMP-AMP synthase (cGAS). Mammalian OASs have been thoroughly characterized as components of the interferon-induced antiviral system. The OAS activity and the respective genes were also discovered in marine sponges where the interferon system is absent. In this study the recombinant OASs from several multicellular animals and their closest unicellular relative, a choanoflagellate, were expressed in a bacterial expression system and their enzymatic activities were examined. We demonstrated 2-5A synthesizing activities of OASs from the marine sponge Tedania ignis, a representative of the phylogenetically oldest metazoan phylum (Porifera), from an invertebrate of the protostome lineage, the mollusk Mytilus californianus (Mollusca), and from a vertebrate species, a cartilaginous fish Leucoraja erinacea (Chordata). However, the expressed proteins from an amphibian, the salamander Ambystoma mexicanum (Chordata), and from a protozoan, the marine choanoflagellate Monosiga brevicollis (Choanozoa), did not show 2-5A synthesizing activity. Differently from other studied OASs, OAS from the marine sponge T. ignis was able to catalyze the formation of oligomers having both 2',5'- and 3',5'-phosphodiester linkages. Our data suggest that OASs from sponges and evolutionarily higher animals have similar activation mechanisms which still include different affinities and possibly different structural requirements for the activating RNAs. Considering their 2'- and 3'-specificities, sponge OASs could represent a link between evolutionarily earlier nucleotidyl transferases and 2'-specific OASs from higher animals. PMID:24184688

  3. The relationship between physicochemical characterization and the potential toxicity of fine particulates (PM 2.5) in Shanghai atmosphere

    NASA Astrophysics Data System (ADS)

    Senlin, Lu; Zhenkun, Yao; Xiaohui, Chen; Minghong, Wu; Guoying, Sheng; Jiamo, Fu; Paul, Daly

    Fine particulate matter with aerodynamic diameter less than 2.5 μm (PM 2.5) was collected at urban and suburban sites in Shanghai from April 2005 to March 2006. Average mass concentrations of PM 2.5 ranged from 43.5 to 149 μg m -3 in the urban area and 21.7 to 159 μg m -3 in suburban area. The mass levels of PM 2.5 sampled at urban and suburban sites showed seasonal variation with much higher values in winter and spring, lower values in summer, and the lowest in autumn. The results of environmental scanning electron microscopy (ESEM) showed that Shanghai PM 2.5 was consisted of soot aggregates, coal fly ashes, minerals, bio-particles and unidentified particles. Inductively coupled plasma atomic mission spectrum (ICP-AES) results showed total elements in Shanghai PM 2.5 increased gradually from summer to winter and remained at a relatively high level in spring. There was a significant difference in the mass of elements in PM 2.5 collected in urban and in suburban atmosphere. Enrichment factor (EF) analysis results demonstrated that K, Na, Ca, Mg, Al, Fe, Ba and Sr originated from natural sources, while As, Cu, Zn, Pb, Cd, Mn, Ni and Se were emitted from anthropogenic sources. The plasmid DNA assay showed that potential toxicity of Shanghai PM 2.5 collected at urban and suburban sampling sites, and in different seasons, varied greatly. Toxicity of the Shanghai urban winter PM 2.5 sample was much stronger compared to any of the other samples. Heavy metals in Shanghai PM 2.5, including Cu, Zn, Pb, Cd, Cr, Mn, and Ni, might have synergic-effects on plasmid DNA damage.

  4. Issues and results in the development of 2. 5 micron filament strand for the HEB

    SciTech Connect

    Seuntjens, J.M.; Capone, D.W. III.

    1991-03-01

    The High Energy Booster (HEB) ring which injects protons into the Superconducting Super Collider (SS) will be ramped with a cycle time on the order of 8 minutes. The current magnet design incorporates a strand with 2.5 {mu}m filaments to reduce the AC loss heating component due to the magnetization hysteresis. The reduced magnetization also makes the correction of the sextupole moment easier. Past experience has shown that Nb-Ti filaments in a copper matrix should have a spacing-to-diameter ratio (s/d) of 0.15 for good fabricability. For 2.5 {mu}m filaments, this results in a spacing on the order of 0.4 {mu}m at final wire size. A Cu-Mn alloy has replaced the copper between the filaments in prototype conductors to effectively eliminate proximity coupling between 2.5 {mu}m filaments which would otherwise occur with copper at this spacing. The resistivity of the material between the filaments is limited by the mean free path being equal to the filament spacing: therefore, cryogenic stability has not been compromised. This paper discusses design and process parameters in the development of 2.5 {mu}m filament conductor production. Data from current 2.5 {mu}m work from several vendors, some of which are on FFP-type contracts sponsored by the SSCL, are included to demonstrate how close industry is to meeting 2.5 {mu}m conductor needs. If the SSCL were unable to bring 2.5 {mu}m conductor into production within about two years' time, a fall-back HEB design with 6 {mu}m filament conductor would be utilized. Therefore, a strong emphasis on manufacturability is reflected in the key issues. The sole purpose of this paper is to establish a common level of understanding of fine filament needs of the SSC; therefore, the data will be purposely presented without vendor affiliation. The authors have paid careful attention to details to avoid the release of proprietary information in this paper. 6 refs., 3 figs., 1 tab.

  5. Recognition of 2',5'-linked oligoadenylates by human ribonuclease L: molecular dynamics study.

    PubMed

    Maláč, Kamil; Barvík, Ivan

    2014-04-01

    The capability of current MD simulations to be used as a tool in rational design of agonists of medically interesting enzyme RNase L was tested. Dimerization and enzymatic activity of RNase L is stimulated by 2',5'-linked oligoadenylates (pA₂₅A₂₅A; 2-5A). First, it was necessary to ensure that a complex of monomeric human RNase L and 25A was stable in MD simulations. It turned out that Glu131 had to be protonated. The non-protonated Glu131 caused dissociation of 2-5A from RNase L. Because of the atypical 2'-5' internucleotide linkages and a specific spatial arrangement of the 25A trimer, when a single molecule carries all possible conformers of the glycosidic torsion angle, several versions of the AMBER force field were tested. One that best maintained functionally important interactions of 25A and RNase L was selected for subsequent MD simulations. Furthermore, we wonder whether powerful GPUs are able to produce MD trajectories long enough to convincingly demonstrate effects of subtle perturbations of interactions between 25A and RNase L. Detrimental impacts of various point mutations of RNase L (R155A, F126A, W60A, K89A) on 2-5A binding were observed on a time scale of 200 ns. Finally, 2-5A analogues with a bridged 3'--O,4'--C-alkylene linkage (B) introduced into the adenosine units (A) were used to assess ability of MD simulations to distinguish on the time scale of hundreds of nanoseconds between agonists of RNase L (pA₂₅A₂₅B, pB₂₅A₂₅A, pB₂₅A₂₅B) and inactive analogs (pA₂₅B₂₅A, pA₂₅B₂₅B, pB₂₅B₂₅A, pB₂₅B₂₅B). Agonists were potently bound to RNase L during 200 ns MD runs. For inactive 2-5A analogs, by contrast, significant disruptions of their interactions with RNase L already within 100 ns MD runs were found. PMID:24633766

  6. The socioeconomic drivers of China’s primary PM2.5 emissions

    NASA Astrophysics Data System (ADS)

    Guan, Dabo; Su, Xin; Zhang, Qiang; Peters, Glen P.; Liu, Zhu; Lei, Yu; He, Kebin

    2014-01-01

    Primary PM2.5 emissions contributed significantly to poor air quality in China. We present an interdisciplinary study to measure the magnitudes of socioeconomic factors in driving primary PM2.5 emission changes in China between 1997-2010, by using a regional emission inventory as input into an environmentally extended input-output framework and applying structural decomposition analysis. Our results show that China’s significant efficiency gains fully offset emissions growth triggered by economic growth and other drivers. Capital formation is the largest final demand category in contributing annual PM2.5 emissions, but the associated emission level is steadily declining. Exports is the only final demand category that drives emission growth between 1997-2010. The production of exports led to emissions of 638 thousand tonnes of PM2.5, half of the EU27 annual total, and six times that of Germany. Embodied emissions in Chinese exports are largely driven by consumption in OECD countries.

  7. [Composition and variation characteristics of atmospheric carbonaceous species in PM 2.5 in Taiyuan, China].

    PubMed

    Zhang, Gui-xiang; Yan, Yu-long; Guo, Li-li; He, Qiu-sheng; Chen, Lai-guo

    2015-03-01

    Day-night variation characteristics of organic carbon (OC) and elemental carbon (EC) in atmospheric fine particles (PM2.5) collected during winter of 2009 and spring of 2010 in Taiyuan city were analyzed using DRI Model 2001A Thermal/Optical Carbon Analyzer, and the sources of carbonaceous materials in PM2.5 were analyzed. The results showed that the average concentrations of PM2.5, OC, EC and average OC/EC ratios were all higher during winter [(289.2 ± 104.8) μg x m(-3), (65.2 ± 22.1) μg x m(-3), (23.5 ± 8.2) μg x m(-3) and 2.8 ± 0.3] than during spring [(248.6 ± 68.6) μg x m(-3), (29.7 ± 6.2) μg x m(-3), (20.2 ± 5.4) μg x m(-3) and 1.5 ± 0.3], higher in nighttime [(309.3 ± 150.0) μg x m(-3), (74.6 ± 19.5) μg x m(-3), (24.3 ± 6.6) μg x m(-3) and 3.1 ± 0.3] than in daytime [(234.9 ± 122.1) μg x m(-3), (54.9 ± 28.2) μg x m(-3), (22.6 ± 10.8) μg x m(-3) and 2.5 ± 0. 5] during winter while higher in daytime [(292.5 ± 120.8) μg x m(-3), (32.7 ± 10.5) μg x m(-3), (22.7 ± 10.1) μg x m(-3) and 1.6 ± 0.5] than in nighttime [(212.3 ± 36.7) μg x m(-3), (29.6 ± 6.6) μg x m(-3), (20.7 ± 6.4) μg x m(-3) and 1.5 ± 0.2] during spring. This result was explained by the fact that winter is a "heating season", especially in nighttime, emission of carbonaceous particles was increased because of the increase of coal and biomass combustion and diffusion of pollutants was difficult because of low atmospheric temperature and stable atmospheric conditions; and high OC/EC was caused by increase of OC emission but not contribution of secondary organic carbon (SOC) since low temperature and weak solar radiation were not favorable for the formation of SOC. The higher concentrations of PM2.5, OC and EC in daytime than in nighttime during spring might be due to more dust in daytime because of higher wind speed and lower relative humidity in daytime than in nighttime, and the higher OC/EC in daytime than in nighttime might be caused by higher temperature

  8. [Composition and variation characteristics of atmospheric carbonaceous species in PM 2.5 in Taiyuan, China].

    PubMed

    Zhang, Gui-xiang; Yan, Yu-long; Guo, Li-li; He, Qiu-sheng; Chen, Lai-guo

    2015-03-01

    Day-night variation characteristics of organic carbon (OC) and elemental carbon (EC) in atmospheric fine particles (PM2.5) collected during winter of 2009 and spring of 2010 in Taiyuan city were analyzed using DRI Model 2001A Thermal/Optical Carbon Analyzer, and the sources of carbonaceous materials in PM2.5 were analyzed. The results showed that the average concentrations of PM2.5, OC, EC and average OC/EC ratios were all higher during winter [(289.2 ± 104.8) μg x m(-3), (65.2 ± 22.1) μg x m(-3), (23.5 ± 8.2) μg x m(-3) and 2.8 ± 0.3] than during spring [(248.6 ± 68.6) μg x m(-3), (29.7 ± 6.2) μg x m(-3), (20.2 ± 5.4) μg x m(-3) and 1.5 ± 0.3], higher in nighttime [(309.3 ± 150.0) μg x m(-3), (74.6 ± 19.5) μg x m(-3), (24.3 ± 6.6) μg x m(-3) and 3.1 ± 0.3] than in daytime [(234.9 ± 122.1) μg x m(-3), (54.9 ± 28.2) μg x m(-3), (22.6 ± 10.8) μg x m(-3) and 2.5 ± 0. 5] during winter while higher in daytime [(292.5 ± 120.8) μg x m(-3), (32.7 ± 10.5) μg x m(-3), (22.7 ± 10.1) μg x m(-3) and 1.6 ± 0.5] than in nighttime [(212.3 ± 36.7) μg x m(-3), (29.6 ± 6.6) μg x m(-3), (20.7 ± 6.4) μg x m(-3) and 1.5 ± 0.2] during spring. This result was explained by the fact that winter is a "heating season", especially in nighttime, emission of carbonaceous particles was increased because of the increase of coal and biomass combustion and diffusion of pollutants was difficult because of low atmospheric temperature and stable atmospheric conditions; and high OC/EC was caused by increase of OC emission but not contribution of secondary organic carbon (SOC) since low temperature and weak solar radiation were not favorable for the formation of SOC. The higher concentrations of PM2.5, OC and EC in daytime than in nighttime during spring might be due to more dust in daytime because of higher wind speed and lower relative humidity in daytime than in nighttime, and the higher OC/EC in daytime than in nighttime might be caused by higher temperature

  9. Ion concentrations of PM10-2.5 and PM2.5 aerosols over the eastern Mediterranean region: seasonal variation and source identification

    NASA Astrophysics Data System (ADS)

    Kouyoumdjian, H.; Saliba, N. A.

    2005-12-01

    The annual averages of particulate matters (PM10, PM10-2.5 (coarse) and PM2.5 (fine)) in a densely populated area of Beirut were measured and found to be 84±27, 53±20 and 31±9 μg m-3, respectively. Ion Chromatography (IC) analysis of the collected PM Teflon filters showed that NaCl, CaSO4 and Ca(NO3)2 were predominant in the coarse particles, while (NH4)2SO4 was the main salt in the fine particles. Using the non destructive Fourier Transform Infra Red-Attenuated Total Reflection (FTIR-ATR) technique, CaCO3 was determined in the coarse filter. In addition, ATR measurements showed that inorganic salts present in the coarse particles are mostly water insoluble while salts found in fine particles are soluble. Concentrations of nitrates and calcium higher than the ones reported in neighboring Mediterranean countries were good indication of high traffic density and crustal dust abundance in Beirut, respectively. The study of the seasonal variation showed that long-range transport of SO2 from Eastern and Central Europe, sandy storms coming from Africa and marine aerosols are considered major sources of the determined inorganic ions. Considering the importance of the health and climate impacts of aerosols locally and regionally, this study constitutes a point of reference for eastern Mediterranean transport modeling studies and local regulatory and policy makers.

  10. Compressional and shear wave velocities in granular materials to 2.5 kilobars

    NASA Technical Reports Server (NTRS)

    Talwani, P.; Nur, A.; Kovach, R. L.

    1973-01-01

    The velocities of seismic compressional waves and, for the first time, shear wave velocities in silica sand, volcanic ash, and basalt powder were determined under hydrostatic confining pressures to 2.5 kb. Simultaneously, the porosity of these materials was obtained as a function of confining pressure. The presented results have important implications for the self-compaction hypothesis that has been postulated to explain the lunar near-surface seismic velocity variation.

  11. Back injuries in a cohort of schoolchildren aged 6-12: A 2.5-year prospective study.

    PubMed

    Franz, C; Jespersen, E; Rexen, C T; Leboeuf-Yde, C; Wedderkopp, N

    2016-08-01

    The aims of this prospective school cohort study were to describe the epidemiology of diagnosed back pain in childhood, classified as either nontraumatic or traumatic back injury, and to estimate the association with physical activity in different settings. Over 2.5 years, 1240 children aged 6-12 years were surveyed weekly using mobile text messages to ask about the presence or absence of back pain. Pain was clinically diagnosed and injuries were classified using the International Classification of Diseases version 10. Physical activity data were obtained from text messages and accelerometers. Of the 315 back injuries diagnosed, 186 injuries were nontraumatic and 129 were traumatic. The incidence rate ratio was 1.5 for a nontraumatic back injury compared with a traumatic injury. The overall estimated back injury incidence rate was 0.20 per 1000 physical activity units (95% confidence interval 0.18-0.23). The back injury incidence rates were higher for sports when exposure per 1000 physical activity units was taken into consideration and especially children horse-riding had a 40 times higher risk of sustaining a traumatic back injury compared to the risk during non-organized leisure time physical activity. However, the reasonably low injury incidence rates support the recommendations of children continuously being physically active. PMID:26130046

  12. PM2.5 pollution in a megacity of southwest China: source apportionment and implication

    NASA Astrophysics Data System (ADS)

    Tao, J.; Gao, J.; Zhang, L.; Zhang, R.; Che, H.; Zhang, Z.; Lin, Z.; Jing, J.; Cao, J.; Hsu, S.-C.

    2014-08-01

    -Fe), defined as the excessive portion in measured Fe that cannot be sustained by mineral dust, is corroborated to be a straightforward useful tracer of iron and steel manufacturing pollution. In Chengdu, Mo / Ni mass ratios were persistently higher than unity, and considerably distinct from those usually observed in ambient airs. V / Ni ratios averaged only 0.7. Results revealed that heavy oil fuel combustion should not be a vital anthropogenic source, and additional anthropogenic sources for Mo are yet to be identified. Overall, the emission sources identified in Chengdu could be dominated by local sources located in the vicinity of Sichuan, a result different from those found in Beijing and Shanghai, wherein cross-boundary transport is significant in contributing pronounced PM2.5. These results provided implications for PM2.5 control strategies.

  13. PM2.5 pollution in a megacity of southwest China: source apportionment and implication

    NASA Astrophysics Data System (ADS)

    Tao, J.; Gao, J.; Zhang, L.; Zhang, R.; Che, H.; Zhang, Z.; Lin, Z.; Jing, J.; Cao, J.; Hsu, S.-C.

    2014-02-01

    -Fe), defined as excessive portion in measured Fe that cannot be sustained by mineral dust, is corroborated to be a straightforward useful tracer of iron and steel manufacturing pollution. In Chengdu, Mo/Ni mass ratios were persistently higher than unity, and considerably distinct from those usually observed in ambient airs. V/Ni ratios averaged at only 0.7. Results revealed that heavy oil fuel combustion should not be a vital anthropogenic source, and additional anthropogenic sources for Mo are yet to be identified. Overall, the emission sources identified in Chengdu could be dominated by local sources located in the vicinity of Sichuan, a result differed from those found in Beijing and Shanghai, wherein cross-boundary transport is significant in contributing pronounced PM2.5. These results provided implications for PM2.5 control strategies.

  14. Determination and source identification of priority polycyclic aromatic hydrocarbons in PM2.5 in Taiyuan, China

    NASA Astrophysics Data System (ADS)

    Zhang, Meng; Xie, Jingfang; Wang, Zhentao; Zhao, Lijuan; Zhang, Hong; Li, Meng

    2016-09-01

    Sixteen polycyclic aromatic hydrocarbons (PAHs) present in PM2. 5 were analyzed in 2012 in Taiyuan (China) using high performance liquid chromatography (HPLC) with fluorescence and ultraviolet detectors. The average daily mass concentrations of ΣPAHs in different seasons ranged from 10.36 ng/m3 to 215.93 ng/m3 and had strong seasonal variation, with highest values in winter and lowest in summer. Over the whole year, PAHs appeared in the following order of frequency: 4-ring > 6-ring > 5-ring > 3-ring; in winter, the percentage of 4-ring PAHs was the highest (62.68%), while in summer, the percentages of 5-ring and 6-ring PAHs (cumulative total of 50.57%) were higher. The ratio method was employed to investigate potential source categories of PAHs in PM2.5 in Taiyuan, with data suggesting that the main PAH sources are coal and wood combustion and vehicle emissions. Finally, a risk assessment of PAHs was performed based on benzo(a)pyrene equivalent (BaPeq) values and individual cancer risk ratios, with results suggesting that the toxicity of PAHs was high during winter and spring time in Taiyuan. The values of incremental lifetime cancer risk (ILCR) induced by whole year inhalation exposure(Ri) for all age groups were larger than 10- 6 in spring and winter, while Ri values for male and female adults in summer and autumn were also larger than 10- 6, indicating high potential carcinogenic risk. During the same season, the ILCR of adults was greater than that of other age groups and that of females was a little higher than of males. With respect to the season, the ranking of ILCR in decreasing order was as follows: winter, spring, autumn, and summer.

  15. Measuring in-cabin school bus tailpipe and crankcase PM2.5: a new dual tracer method.

    PubMed

    Ireson, Robert G; Ondov, John M; Zielinska, Barbara; Weaver, Christopher S; Easter, Michael D; Lawson, Douglas R; Hesterberg, Thomas W; Davey, Mark E; Liu, L-J Sally

    2011-05-01

    Exposures of occupants in school buses to on-road vehicle emissions, including emissions from the bus itself, can be substantially greater than those in outdoor settings. A dual tracer method was developed and applied to two school buses in Seattle in 2005 to quantify in-cabin fine particulate matter (PM2.5) concentrations attributable to the buses' diesel engine tailpipe (DPMtp) and crankcase vent (PMck) emissions. The new method avoids the problem of differentiating bus emissions from chemically identical emissions of other vehicles by using a fuel-based organometallic iridium tracer for engine exhaust and by adding deuterated hexatriacontane to engine oil. Source testing results showed consistent PM:tracer ratios for the primary tracer for each type of emissions. Comparisons of the PM:tracer ratios indicated that there was a small amount of unburned lubricating oil emitted from the tailpipe; however, virtually no diesel fuel combustion products were found in the crankcase emissions. For the limited testing conducted here, although PMck emission rates (averages of 0.028 and 0.099 g/km for the two buses) were lower than those from the tailpipe (0.18 and 0.14 g/km), in-cabin PMck concentrations averaging 6.8 microg/m3 were higher than DPMtp (0.91 microg/m3 average). In-cabin DPMtp and PMck concentrations were significantly higher with bus windows closed (1.4 and 12 microg/m3, respectively) as compared with open (0.44 and 1.3 microg/m3, respectively). For comparison, average closed- and open-window in-cabin total PM2.5 concentrations were 26 and 12 microg/m3, respectively. Despite the relatively short in-cabin sampling times, very high sensitivities were achieved, with detection limits of 0.002 microg/m3 for DPMtp and 0.05 microg/m3 for PMck. PMID:21608489

  16. [Characteristics of PM10 and PM2.5 concentrations in mountain background region of East China].

    PubMed

    Su, Bin-Bin; Liu, Xin-Dong; Tao, Jun

    2013-02-01

    The online PM10 and PM2.5 concentrations were measured from March 2011 'to February 2012 at the national atmospheric background monitoring station in Wuyishan of Fujian Province to discuss the characteristic of PM10 and PM2.5 concentrations and the impact factors in forest and mountain background region of East China. HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) Model was used to investigate the potential sources of particulates during the pollution episodes. The results showed that the background concentrations of PM10 and PM2.5 were (23 +/- 16) microg.m-3 and (18 +/- 12) microg.m-3, respectively. Seasonal variations of PMl0 and PM2.5 loadings were observed, and loadings decreased in the same order: spring > autumn > winter > summer. PM10 and PM2.5 concentrations were obviously higher in spring than in other seasons because of the transportation of dust storm. The fine particles were the dominant pollutant which accounted for 76% of PM10. The good correlation between PM10/PM2.5 and gas pollutants suggested that regional transportation and secondary aerosol were the major sources in the background station. One episode occurring in April 2011 was related with the transportation of dust storm. However, another episode occurring in September 2011 had close relationship with the transportation of higher pollutant loadings in East China. PMID:23668109

  17. [Characteristics of PM10 and PM2.5 concentrations in mountain background region of East China].

    PubMed

    Su, Bin-Bin; Liu, Xin-Dong; Tao, Jun

    2013-02-01

    The online PM10 and PM2.5 concentrations were measured from March 2011 'to February 2012 at the national atmospheric background monitoring station in Wuyishan of Fujian Province to discuss the characteristic of PM10 and PM2.5 concentrations and the impact factors in forest and mountain background region of East China. HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory) Model was used to investigate the potential sources of particulates during the pollution episodes. The results showed that the background concentrations of PM10 and PM2.5 were (23 +/- 16) microg.m-3 and (18 +/- 12) microg.m-3, respectively. Seasonal variations of PMl0 and PM2.5 loadings were observed, and loadings decreased in the same order: spring > autumn > winter > summer. PM10 and PM2.5 concentrations were obviously higher in spring than in other seasons because of the transportation of dust storm. The fine particles were the dominant pollutant which accounted for 76% of PM10. The good correlation between PM10/PM2.5 and gas pollutants suggested that regional transportation and secondary aerosol were the major sources in the background station. One episode occurring in April 2011 was related with the transportation of dust storm. However, another episode occurring in September 2011 had close relationship with the transportation of higher pollutant loadings in East China.

  18. Differences in allergic inflammatory responses between urban PM2.5 and fine particle derived from desert-dust in murine lungs.

    PubMed

    He, Miao; Ichinose, Takamichi; Kobayashi, Makoto; Arashidani, Keiichi; Yoshida, Seiichi; Nishikawa, Masataka; Takano, Hirohisa; Sun, Guifan; Shibamoto, Takayuki

    2016-04-15

    The biological and chemical natures of materials adsorbed onto fine particulate matter (PM2.5) vary by origin and passage routes. The exacerbating effects of the two samples-urban PM2.5 (U-PM2.5) collected during the hazy weather in a Chinese city and fine particles (ASD-PM2.5) collected during Asian sand dust (ASD) storm event days in Japan-on murine lung eosinophilia were compared to clarify the role of toxic materials in PM2.5. The amounts of β-glucan and mineral components were higher in ASD-PM2.5 than in U-PM2.5. On the other hand, organic chemicals, including polycyclic aromatic hydrocarbons (PAHs), were higher in U-PM2.5 than in ASD-PM2.5. When BALB/c mice were intratracheally instilled with U-PM2.5 and ASD-PM2.5 (total 0.4 mg/mouse) with or without ovalbumin (OVA), various biological effects were observed, including enhancement of eosinophil recruitment induced by OVA in the submucosa of the airway, goblet cell proliferation in the bronchial epithelium, synergic increase of OVA-induced eosinophil-relevant cytokines and a chemokine in bronchoalveolar lavage fluid, and increase of serum OVA-specific IgG1 and IgE. Data demonstrate that U-PM2.5 and ASD-PM2.5 induced allergic inflammatory changes and caused lung pathology. U-PM2.5 and ASD-PM2.5 increased F4/80(+) CD11b(+) cells, indicating that an influx of inflammatory and exudative macrophages in lung tissue had occurred. The ratio of CD206 positive F4/80(+) CD11b(+) cells (M2 macrophages) in lung tissue was higher in the OVA+ASD-PM2.5 treated mice than in the OVA+U-PM2.5 treated mice. These results suggest that the lung eosinophilia exacerbated by both PM2.5 is due to activation of a Th2-associated immune response along with induced M2 macrophages and the exacerbating effect is greater in microbial element (β-glucan)-rich ASD-PM2.5 than in organic chemical-rich U-PM2.5. PMID:26917405

  19. Time Is Money...and the Enemy of College Completion: Transform American Higher Education to Boost Completion and Reduce Costs. Testimony before the United States House of Representatives Subcommittee on Higher Education and Workforce Training

    ERIC Educational Resources Information Center

    Jones, Stan

    2012-01-01

    This paper presents Stan Jones' testimony before the United States House of Representatives Subcommittee on Higher Education and Workforce Training. In his testimony, he talks about a new American majority of students that is emerging on campuses, especially at community colleges. These students must delicately balance long hours at jobs they must…

  20. A study of PM2.5 and PM10 concentrations in the atmosphere of large cities in Gansu Province, China, in summer period

    NASA Astrophysics Data System (ADS)

    Filonchyk, Mikalai; Yan, Haowen; Yang, Shuwen; Hurynovich, Volha

    2016-08-01

    Due to rapid economic growth of the country in the last 25 years, particulate matter (PM) has become a topic of great interest in China. The rapid development of industry has led to an increase in the haze created by pollution, as well as by high levels of urbanization. In 2012, the Chinese National Ambient Air Quality Standard (NAAQS) imposed `more strict' regulation on the PM concentrations, i.e., 35 and 70 μg/m3 for annual PM2.5 and PM10 in average, respectively (Grade-II, GB3095-2012). The Pearson's correlation coefficient was used to determine the linear relationship of pollution between pollution levels and weather conditions as well as the temporal and spatial variability among neighbouring cities. The goal of this paper was to investigate hourly mass concentration of PM2.5 and PM10 from June 1 to August 31, 2015 collected in the 11 largest cities of Gansu Province. This study has shown that the overall average concentrations of PM2.5 and PM10 in the study area were 26 and 66 μg/m3. In PM2.5 episode days (when concentration was more than 75 μg/m3 for 24 hrs), the average concentrations of PM2.5 was 2-3 times higher as compared to non-episode days. There were no observed clear differences during the weekday/weekend PM and other air pollutants (SO2, NO2, CO and O3) in all the investigated cities.

  1. 2,5-Dihydroxybenzoic acid: laser desorption/ionisation as a function of elevated temperature

    NASA Astrophysics Data System (ADS)

    Wallace, W. E.; Arnould, M. A.; Knochenmuss, R.

    2005-03-01

    The temperature dependence of laser desorption/ionization (LDI) ion yields has been measured for 2,5-dihydroxybenzoic acid (2,5-DHB) single crystals from room temperature to 160 °C using time-of-flight (TOF) mass spectrometry. A steep rise in ion production occurs at 90 °C, achieving a maximum at 120 °C, then decreases sharply to a minimum at 140 °C, and returns to a second maximum at 150 °C. Above 160 °C, useful information could not be obtained because of rapid volatilization of the sample into the vacuum. The overall trend in ion production, but not some of the details, is well described by a recent two-step theory of the laser desorption/ionization process, which takes into account the temperature-dependent effects of plume expansion. Measuring the background vacuum composition with a quadrupole mass spectrometer residual gas analyzer (RGA) showed an increase in thermal desorption of 2,5-DHB starting at 90 °C and maximizing at 130 °C. The increased neutral production by thermal desorption is believed to be the cause of the decrease in LDI ion production due to reduced pooling probabilities for laser-excited 2,5-DHB molecules. Thermal dehydration, condensation, and decarboxylation increase the volume of gas released at high temperatures which also serve to decrease LDI ion production at elevated temperatures. Lastly, to confirm the mass spectrometry results, the thermal desorption of 2,5-DHB single crystals under vacuum was measured using a quartz-crystal microbalance (QCM). The onset of desorption was found to occur at 90 °C and the maximum desorption rate was found at 135 °C.

  2. Scavenging of PM2.5 by precipitation and the effects of precipitation pattern changes on health risks related to PM2.5 in Tokyo, Japan.

    PubMed

    Ikeuchi, Hiroaki; Murakami, Michio; Watanabe, Satoshi

    2015-01-01

    Fine particulate matter (aerodynamic diameter<2.5 μm; PM2.5) poses risks to human health. While precipitation is the main process for decreasing ambient pollutant concentrations, scavenging of PM2.5 by precipitation remains to be investigated. Here we formulated the processes of PM2.5 scavenging by precipitation from observed PM2.5 concentrations ([PM2.5]) and precipitation intensities. Then we analyzed how changes in precipitation patterns would affect health risks related to PM2.5 on the basis of a Monte Carlo simulation. Tokyo, the capital of Japan, was selected as the target for this study because of its social significance. We found that [PM2.5] decreased significantly through scavenging of PM2.5 from the atmosphere by precipitation. In contrast, we found no significant correlation between reduction of [PM2.5] and precipitation intensity. Our model for estimating the reduction of PM2.5 and the Monte Carlo simulation showed good agreement with observations. Among various changes in potential precipitation patterns, changes in the arithmetic mean of the number of events and/or in precipitation duration were more influential on reduction of [PM2.5] than changes in their standard deviations. Health risks due to PM2.5 will increase with decreases in precipitation duration and occurrence.

  3. Mechanism of charge transport in poly(2,5-dimethoxyaniline)

    NASA Astrophysics Data System (ADS)

    Singh, Rajiv K.; Kumar, Amit; Singh, Ramadhar

    2010-06-01

    Poly(2,5-dimethoxyaniline) (PDMA) has been synthesized by chemical oxidative polymerization technique using varying ratio of oxidants; ferric chloride (FeCl3) and ammonium persulfate [(NH4)2S2O8], in an inert atmosphere at low temperature ˜278 K. The synthesized samples of PDMA have been characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and by measuring its dc conductivity (σdc). The temperature dependence of dc conductivity of PDMA samples has been examined in the wide temperature range 6-303 K. The analysis of dc conductivity data reveals that in the temperature range ˜100-303 K, the dc conductivity is predominantly governed by Mott's three-dimensional variable range hopping, however, below 100 K tunneling seems to dominate. Different Mott's parameters such as characteristic temperature (T0), density of states at the Fermi level [N(EF)], the average hopping distance (R ), and the average hopping energy (W) have been estimated for all the PDMA samples and are in good agreement with the values reported earlier for other conjugated polymers.

  4. Impact of Fine Particulate Matter (PM2.5) Exposure During Wildfires on Cardiovascular Health Outcomes

    PubMed Central

    Haikerwal, Anjali; Akram, Muhammad; Del Monaco, Anthony; Smith, Karen; Sim, Malcolm R; Meyer, Mick; Tonkin, Andrew M; Abramson, Michael J; Dennekamp, Martine

    2015-01-01

    Background Epidemiological studies investigating the role of fine particulate matter (PM2.5; aerodynamic diameter <2.5 μm) in triggering acute coronary events, including out-of-hospital cardiac arrests and ischemic heart disease (IHD), during wildfires have been inconclusive. Methods and Results We examined the associations of out-of-hospital cardiac arrests, IHD, acute myocardial infarction, and angina (hospital admissions and emergency department attendance) with PM2.5 concentrations during the 2006–2007 wildfires in Victoria, Australia, using a time-stratified case-crossover study design. Health data were obtained from comprehensive health-based administrative registries for the study period (December 2006 to January 2007). Modeled and validated air exposure data from wildfire smoke emissions (daily average PM2.5, temperature, relative humidity) were also estimated for this period. There were 457 out-of-hospital cardiac arrests, 2106 emergency department visits, and 3274 hospital admissions for IHD. After adjusting for temperature and relative humidity, an increase in interquartile range of 9.04 μg/m3 in PM2.5 over 2 days moving average (lag 0-1) was associated with a 6.98% (95% CI 1.03% to 13.29%) increase in risk of out-of-hospital cardiac arrests, with strong association shown by men (9.05%,95%CI 1.63% to 17.02%) and by older adults (aged ≥65 years) (7.25%, 95% CI 0.24% to 14.75%). Increase in risk was (2.07%, 95% CI 0.09% to 4.09%) for IHD-related emergency department attendance and (1.86%, 95% CI: 0.35% to 3.4%) for IHD-related hospital admissions at lag 2 days, with strong associations shown by women (3.21%, 95% CI 0.81% to 5.67%) and by older adults (2.41%, 95% CI 0.82% to 5.67%). Conclusion PM2.5 exposure was associated with increased risk of out-of-hospital cardiac arrests and IHD during the 2006–2007 wildfires in Victoria. This evidence indicates that PM2.5 may act as a triggering factor for acute coronary events during wildfire episodes

  5. Indoor PM2.5 in Santiago, Chile, spring 2012: Source apportionment and outdoor contributions

    NASA Astrophysics Data System (ADS)

    Barraza, Francisco; Jorquera, Héctor; Valdivia, Gonzalo; Montoya, Lupita D.

    2014-09-01

    Indoor and outdoor PM2.5 sampling campaigns were carried out at Santiago, Chile (6 million inhabitants, 33.5°S, 70.6°W) in spring 2012. A pair of samplers was placed inside each household studied and an additional pair of samplers was placed at a fixed outdoor location for measuring trace elements and elemental (EC) and organic carbon (OC) in Teflon and quartz filters, respectively. A total of 47 households in downtown Santiago were included in this study. Mean outdoor and indoor PM2.5 concentrations were 19.2 and 21.6 μg/m3, respectively. Indoor concentrations of PM2.5 were affected by socioeconomic status (p = 0.048) but no such evidence was found for PM2.5 species, except lead (p = 0.046). Estimated species infiltration factors were 0.70 (±0.19), 0.98 (±0.21), 0.80 (±0.12) and 0.80 (±0.03) for PM2.5, OC, EC and sulfur, respectively. Estimated household infiltration factors had a median of 0.75, mean of 0.78, standard deviation of 0.18 and interquartile range (IQR) 0.67-0.86. For the very first time, Positive Matrix Factorization (PMF3) was applied to an indoor PM2.5 chemical composition data set measured at Santiago. Source identification was carried out by inspection of key species and by comparison with published source profiles; six sources were identified. Three of them were outdoor contributions: motor vehicles with 5.6 (±0.7) μg/m3, street dust with 2.9 (±0.5) μg/m3 and secondary sulfates with 3.4 (±0.5) μg/m3. The indoor sources were: indoor dust with 1.6 (±0.3) μg/m3, cleaning and cooking with 2.3 (±0.3) μg/m3 and cooking and environmental tobacco smoke with 6.1 (±0.7) μg/m3. There is potential for further reducing PM2.5 population exposure in the short term -by improving ventilation of indoor air and controlling indoor sources - and in the long term - with filtration of outdoor air and household improvements to reduce air change rates.

  6. Platinum in PM2.5 of the metropolitan area of Mexico City.

    PubMed

    Morton-Bermea, Ofelia; Amador-Muñoz, Omar; Martínez-Trejo, Lida; Hernández-Álvarez, Elizabeth; Beramendi-Orosco, Laura; García-Arreola, María Elena

    2014-10-01

    The increase in platinum (Pt) in the airborne particulate matter with size ≤2.5 µm (PM2.5) in urban environments may be interpreted as result of the abrasion and deterioration of automobile catalyst. Nowadays, about four million vehicles in Mexico City use catalytic converters, which means that their impact should be considered. In order to evaluate the contribution of Pt to environmental pollution of the metropolitan area of Mexico City (MAMC), airborne PM2.5 was collected at five different sites in the urban area (NW, NE, C, SW, SE) in 2011 during April (dry-warm season), August (rainy season) and December (dry-cold season). Analytical determinations were carried out using a ICP-MS with a collision cell and kinetic energy discrimination. The analytical and instrument performance was evaluated with standard road dust reference material (BCR-723). Median Pt concentration in the analyzed particulate was is 38.4 pg m(-3) (minimal value 1 pg m(-3) maximal value 79 pg m(-3)). Obtained Pt concentrations are higher than those reported for other urban areas. Spatial variation shows that SW had Pt concentration significantly higher than NW and C only. Seasonal variation shows that Pt median was higher in rainy season than in both dry seasons. A comparison of these results with previously reported data of PM10 from 1991 and 2003 in the same studied area shows a worrying increase in the concentration of Pt in the air environment of MAMC. PMID:24729077

  7. Evaluation of EA-934NA with 2.5 percent Cab-O-Sil

    NASA Technical Reports Server (NTRS)

    Caldwell, Gordon A.

    1990-01-01

    Currently, Hysol adhesive EA-934NA is used to bond the Field Joint Protection System on the Shuttle rocket motors at Kennedy Space Center. However, due to processing problems, an adhesive with a higher viscosity is needed to alleviate these difficulties. One possible solution is to add Cab-O-Sil to the current adhesive. The adhesive strength and bond strengths that can be obtained when 2.5 percent Cab-O-Sil is added to adhesive EA-934NA are examined and tested over a range of test temperatures from -20 to 300 F. Tensile adhesion button and lap shear specimens were bonded to D6AC steel and uniaxial tensile specimens (testing for strength, initial tangent modulus, elongation and Poisson's ratio) were prepared using Hysol adhesive EA-934NA with 2.5 percent Cab-O-Sil added. These specimens were tested at -20, 20, 75, 100, 125, 150, 200, 250, and 300 F, respectively. Additional tensile adhesion button specimens bonding Rust-Oleum primed and painted D6AC steel to itself and to cork using adhesive EA-934NA with 2.5 percent Cab-O-Sil added were tested at 20, 75, 125, 200, and 300 F, respectively. Results generally show decreasing strength values with increasing test temperatures. The bond strengths obtained using cork as a substrate were totally dependent on the cohesive strength of the cork.

  8. Chemical composition and bioreactivity of PM2.5 during 2013 haze events in China

    NASA Astrophysics Data System (ADS)

    Ho, Kin-Fai; Ho, Steven Sai Hang; Huang, Ru-Jin; Chuang, Hsiao-Chi; Cao, Jun-Ji; Han, Yongming; Lui, Ka-Hei; Ning, Zhi; Chuang, Kai-Jen; Cheng, Tsun-Jen; Lee, Shun-Cheng; Hu, Di; Wang, Bei; Zhang, Renjian

    2016-02-01

    Chemical composition and bioreactivity of PM2.5 samples collected from Beijing (BJ), Xi'an (XA), Xiamen (XM) and Hong Kong (HK) in China during haze events were characterized. PM2.5 mass concentrations in BJ, XA, XM and HK in the episodes were found to be 258 ± 100 μg m-3, 233 ± 52 μg m-3, 46 ± 9 μg m-3 and 48 ± 13 μg m-3, respectively. Significant increase of sulfate, nitrate and ammonium concentrations in northern cities were observed. High contributions of biomass burning emissions to organic carbon (OC) in northern cities were estimated in this study implying frequent biomass burning during the haze periods. The urea concentrations in PM2.5 were 1855 ± 755 ng m-3 (BJ), 1124 ± 243 ng m-3 (XA), 543 ± 104 ng m-3 (XM) and 363 ± 61 ng m-3 (HK) suggesting higher or close to upper limits compared to other regions in the world. Dose-dependent alterations in oxidative potential, IL-6, IFN-γ and TNF-α levels were also investigated. The oxidative potential levels are BJ > XM > XA > HK, whereas levels of IL-6, IFN-γ and TNF-α were BJ > XA > XM > HK. The sulfate, nitrate, ammonium, OC, urea and levoglucosan are associated with oxidative-inflammatory responses. These experimental results are crucial for the policymakers to implement cost-effective abatement strategies for improving air quality.

  9. [Pollution characteristics of organic and elemental carbon in PM2.5 in Taiyuan].

    PubMed

    Liu, Shan; Peng, Lin; Wen, Yan-ping; Bai, Hui-ling; Liu, Feng-xian; Shi, Mei-Xian; Li, Li-juan

    2015-02-01

    PM2.5 samples were collected at four sampling sites to study pollution characteristics of carbonaceous aerosols in Taiyuan during winter and summer. Organic carbon (OC) and elemental carbon (EC) in PM2.5 were analyzed by carbon analyzer, and the characteristics including pollution levels, temporal and spatial distributions of OC and EC, secondary organic carbon (SOC) and relationships of OC and EC were discussed in detail. The average concentrations of OC and EC in winter were 22.3 μg x m(-3) and 18.3 μg x m(-3), respectively, while in summer were 13.1 μg x m(-3) and 9.8 μg x m(-3), respectively. The concentrations of total carbon aerosol (TCA) accounted for 56.6% of PM2.5 in winter, and 36.5% in summer; the concentrations of OC and EC at four sites in winter were higher than those in summer, OC and EC levels showed a good uniformity in winter while in summer, the spatial distributions of OC and EC were obviously different; SOC levels were lighter than other cities; the correlation between OC and EC was stronger in winter than that in summer.

  10. Improvement of desulfurization activity in Rhodococcus erythropolis KA2-5-1 by genetic engineering.

    PubMed

    Hirasawa, K; Ishii, Y; Kobayashi, M; Koizumi, K; Maruhashi, K

    2001-02-01

    Rhodococcus erythropolis KA2-5-1 can desulfurize dibenzothiophene (DBT) into 2-hydroxybiphenyl. A cryptic plasmid, pRC4, which was derived from R. rhodochrous IFO3338, was combined with an Escherichia coli vector to construct an E. coli-Rhodococcus shuttle vector. The complete nucleotide sequence of 2582-bp pRC4 was analyzed. Based on the characteristics of its putative replication genes, pRC4 was assigned to the family of pAL5000-related replicons. The desulfurization gene cluster, dszABC, and the related reductase gene, dszD, cloned from KA2-5-1, were reintroduced into KA2-5-1 and efficiently expressed. The DBT desulfurization ability of the transformant carrying two dszABC clusters and one dszD on the vector was about 4-fold higher than that of the parent strain, and the transformant also showed improved desulfurization activity for light gas oil (LGO). Sulfur components in LGO before and after the reaction were analyzed with gas chromatography-atomic emission detection.

  11. Estimating PM2.5 in the Beijing-Tianjin Region Using Modis Aod Products from 2014 TO 2015

    NASA Astrophysics Data System (ADS)

    Li, Yuenan; Wang, Jianjun; Chen, Cheng; Chen, Yifei; Li, Jonathan

    2016-06-01

    Fine particulate matter with a diameter less than 2.5 μm (PM2.5) has harmful impacts on regional climate, economic development and public health. The high PM2.5 concentrations in China's urban areas are mainly caused by the combustion of coal and gasoline, industrial pollution and unknown/uncertain sources. The Beijing-Tianjin-Hebei (BTH) region with a land area of 218,000 km2, which contains 13 cities, is the biggest urbanized region in northern China. The huge population (110 million, 8% of the China's population), local heavy industries and vehicle emissions have resulted in severe air pollution. Traditional models have used 10 km Moderate-resolution Imaging Spectroradiometer (MODIS) Aerosol Optical Depth (AOD) products and proved the statistical relationship between AOD and PM2.5. In 2014, the 3 km MODIS AOD product was released which made PM2.5 estimations with a higher resolution became possible. This study presents an estimation on PM2.5 distributions in the BTH region from September 2014 to August 2015 by combining the MODIS satellite data, ground measurements of PM2.5, meteorological parameters and social-economic factors based on the geographically weighted regression model. The results demonstrated that the 10 km AOD product provided results with a slightly higher accuracy although the 3 km AOD product could provide more information about the spatial variations of PM2.5 estimations. Additionally, compared with the global regression, the geographically weighed model was able to improve the estimation results.

  12. Economic Impacts from PM2.5 Pollution-Related Health Effects in China: A Provincial-Level Analysis.

    PubMed

    Xie, Yang; Dai, Hancheng; Dong, Huijuan; Hanaoka, Tatsuya; Masui, Toshihiko

    2016-05-01

    This study evaluates the PM2.5 pollution-related health impacts on the national and provincial economy of China using a computable general equilibrium (CGE) model and the latest nonlinear exposure-response functions. Results show that the health and economic impacts may be substantial in provinces with a high PM2.5 concentration. In the WoPol scenario without PM2.5 pollution control policy, we estimate that China experiences a 2.00% GDP loss and 25.2 billion USD in health expenditure from PM2.5 pollution in 2030. In contrast, with control policy in the WPol scenario, a control investment of 101.8 billion USD (0.79% of GDP) and a gain of 1.17% of China's GDP from improving PM2.5 pollution are projected. At the provincial level, GDP loss in 2030 in the WoPol scenario is high in Tianjin (3.08%), Shanghai (2.98%), Henan (2.32%), Beijing (2.75%), and Hebei (2.60%) and the top five provinces with the highest additional health expenditure are Henan, Sichuan, Shandong, Hebei, and Jiangsu. Controlling PM2.5 pollution could bring positive benefits in two-thirds of provinces. Tianjin, Shanghai, Beijing, Henan, Jiangsu, and Hebei experience most benefits from PM2.5 pollution control as a result of a higher PM2.5 pollution and dense population distribution. Conversely, the control investment is higher than GDP gain in some underdeveloped provinces, such as Ningxia, Guizhou, Shanxi, Gansu, and Yunnan.

  13. A systematic analysis of PM2.5 in Beijing and its sources from 2000 to 2012

    NASA Astrophysics Data System (ADS)

    Lv, Baolei; Zhang, Bin; Bai, Yuqi

    2016-01-01

    Particulate matter with an aerodynamic diameter of 2.5 μm or less (PM2.5) is the main air pollutant in Beijing. To have a comprehensive understanding of concentrations, compositions and sources of PM2.5 in Beijing, recent studies reporting ground-based observations and source apportionment results dated from 2000 to 2012 in this typical large city of China are reviewed. Statistical methods were also used to better enable data comparison. During the last decade, annual average concentrations of PM2.5 have decreased and seasonal mean concentrations declined through autumn and winter. Generally, winter is the most polluted season and summer is the least polluted one. Seasonal variance of PM2.5 levels decreased. For diurnal variance, PM2.5 generally increases at night and decreases during the day. On average, organic matters, sulfate, nitrate and ammonium are the major compositions of PM2.5 in Beijing. Fractions of organic matters increased from 2000 to 2004, and decreased afterwards. Fractions of sulfate, nitrate and ammonium decreased in winter and remained largely unchanged in summer. Concentrations of organic carbon and elemental carbon were always higher in winter than in summer and they barely changed during the last decade. Concentrations of sulfate, nitrate and ammonium exhibited significant increasing trend in summer but in reverse in winter. On average they were higher in winter than in summer before 2005, and took a reverse after 2005. Receptor model results show that vehicle, dust, industry, biomass burning, coal combustion and secondary products were major sources and they all increased except coal combustions and secondary products. The growth was decided both changing social and economic activities in Beijing, and most likely growing emissions in neighboring Hebei province. Explicit descriptions of the spatial variations of PM2.5 concentration, better methods to estimate secondary products and ensemble source apportionments models to reduce

  14. Factors influencing variability in the infiltration of PM2.5 mass and its components

    NASA Astrophysics Data System (ADS)

    MacNeill, M.; Wallace, L.; Kearney, J.; Allen, R. W.; Van Ryswyk, K.; Judek, S.; Xu, X.; Wheeler, A.

    2012-12-01

    The infiltration of particles into homes can vary seasonally, between homes in a community and between communities. However, few studies have examined the day to day variability across multiple homes. We used continuous data collected from a 2-year (2005-2006) personal exposure study conducted in Windsor, ON to estimate daily infiltration factors (Finf) for fine particulate matter (PM2.5), Black Carbon (BC), and ultrafine particles (UFP) as well as the ambient personal exposure factor (Fpex) for PM2.5. In addition, the daily ambient and non-ambient generated components of indoor and personal concentrations were estimated. Median daily Finf estimates ranged from 0.26 to 0.36 across seasons for PM2.5; from 0.28 to 0.59 for BC; and from 0.15 to 0.26 for UFP. Median daily Fpex estimates ranged from 0.24 to 0.31 across seasons. Daily PM2.5 and UFP Finf and Fpex estimates were higher in summer than winter, although BC showed the opposite trend. Predictors of daily infiltration were typically related to window-opening behaviours, air conditioning, meteorological variables, and home age. In addition, use of electrostatic precipitators and stand alone air cleaners was associated with significantly reduced infiltration factors, indicating that these devices may provide a cost effective mechanism of reducing human exposures to particles of ambient origin. The majority of indoor PM2.5 (median 57-73%) and indoor BC (median 90-100%) was of ambient origin across seasons, while both personal PM2.5 and indoor UFPs had significant non-ambient contributions (median 60-65%). Factors that were found to increase non-ambient particle concentrations were typically related to cooking, candle use, supplemental heating, cleaning, and number of people in the home. Factors that were found to decrease non-ambient particle concentrations were open windows, and air cleaner use. This work has several implications to both epidemiologic studies and risk management. A better understanding of the

  15. Phthalate esters (PAEs) in indoor PM10/PM2.5 and human exposure to PAEs via inhalation of indoor air in Tianjin, China

    NASA Astrophysics Data System (ADS)

    Zhang, Leibo; Wang, Fumei; Ji, Yaqin; Jiao, Jiao; Zou, Dekun; Liu, Lingling; Shan, Chunyan; Bai, Zhipeng; Sun, Zengrong

    2014-03-01

    In this study, filter samples of six Phthalate esters (PAEs) in indoor PM10 and PM2.5 were collected from thirteen homes in Tianjin, China. The results showed that the concentrations of Σ6PAEs in indoor PM10 and PM2.5 were in the range of 13.878-1591.277 ng m-3 and 7.266-1244.178 ng m-3, respectively. Dibutyl phthalate (DBP) was the most abundant compounds followed by di-2-ethylhexyl phthalate (DEHP) in indoor PM10 and PM2.5. Whereas DBP and dimethyl phthalate (DMP) were the predominant compounds in indoor air (gas-phase + particle-phase), the median values were 573.467 and 368.364 ng m-3 respectively. The earlier construction time, the lesser indoor area, the old decoration, the very crowded items coated with plastic and a lower frequency of dusting may lead to a higher level of PAEs in indoor environment. The six PAEs in indoor PM10 and PM2.5 were higher in summer than those in winter. The daily intake (DI) of six PAEs for five age groups through air inhalation in indoor air in Tianjin was estimated. The results indicated that the highest exposure dose was DBP in every age group, and infants experienced the highest total DIs (median: 664.332 ng kg-bw-1 day-1) to ∑6PAEs, whereas adults experienced the lowest total DIs (median: 155.850 ng kg-bw-1 day-1) to ∑6PAEs. So, more attention should be paid on infants in the aspect of indoor inhalation exposure to PAEs.

  16. Modeling the spatio-temporal heterogeneity in the PM10-PM2.5 relationship

    NASA Astrophysics Data System (ADS)

    Chu, Hone-Jay; Huang, Bo; Lin, Chuan-Yao

    2015-02-01

    This paper explores the spatio-temporal patterns of particulate matter (PM) in Taiwan based on a series of methods. Using fuzzy c-means clustering first, the spatial heterogeneity (six clusters) in the PM data collected between 2005 and 2009 in Taiwan are identified and the industrial and urban areas of Taiwan (southwestern, west central, northwestern, and northern Taiwan) are found to have high PM concentrations. The PM10-PM2.5 relationship is then modeled with global ordinary least squares regression, geographically weighted regression (GWR), and geographically and temporally weighted regression (GTWR). The GTWR and GWR produce consistent results; however, GTWR provides more detailed information of spatio-temporal variations of the PM10-PM2.5 relationship. The results also show that GTWR provides a relatively high goodness of fit and sufficient space-time explanatory power. In particular, the PM2.5 or PM10 varies with time and space, depending on weather conditions and the spatial distribution of land use and emission patterns in local areas. Such information can be used to determine patterns of spatio-temporal heterogeneity in PM that will allow the control of pollutants and the reduction of public exposure.

  17. TASK 2.5.5 NATURAL EXPOSURE TESTING IN CALIFORNIA

    SciTech Connect

    Miller, William A; Cheng, Mengdawn; New, Joshua Ryan; Ronnen, Levinson; Akbari, Hashem; Berhahl, Paul

    2010-03-01

    Airborne particulate matter that settles on a roof can either reflect or absorb incoming solar radiation, dependent on the chemical content and size of the particles. These light scattering and absorption processes occur within a few microns of the surface, and can affect the solar reflectance of the roof. Wilkes et al. (2000) tested 24 different roof coatings on a low-slope test stand and observed about a 25% decrease in the solar reflectance of white-coated and aluminum-coated surfaces as the time of exposure increased; however, the decrease leveled off after 2 years. SPRI Inc. and its affiliates studied the effect of climatic exposure on the surface properties of white thermoplastic single-ply membranes and determined that membranes lose from 30 to 50% of their reflectance over 3 years (Miller et al. 2002). The CMRC and its affiliates AISI, NamZAC, MBMA, MCA and NCCA exposed unpainted and painted metal roofing on both steep- and low-slope test roofs and found that after 3 years, the painted polyvinylidene fluoride (PVDF) metal roofs lost less than 5% of their original reflectance (Miller et al. 2004). The results of the three different weathering studies are very interesting in terms of their solar reflectance after 3 years of exposure. The white thermoplastic membrane and white ceramic coating with white topcoat had original reflectance measures that were about 20 percentage points higher than the painted metal; however, after 3-years of field exposure the solar reflectance of the painted metal exceeds that of the thermoplastic membrane and equals that of the coating. The long-term loss of reflectance appears driven by the ability of the particulate matter to cling to the roof and resist being washed off by wind and or rain. Miller et al. (2002) discovered that aerosol deposition introduced biomass of complex microbial consortia onto the test roofs and the combination of contaminants and biomass accelerated the loss of solar reflectance for the thermoplastic

  18. Influence of Climate on PM2.5 Concentrations over Europe : a Meteorological Analysis using a 9-year Model Simulation

    NASA Astrophysics Data System (ADS)

    Lecoeur, À.; Seigneur, C.; Terray, L.; Pagé, C.

    2012-04-01

    experimentally verify some intuitive results: weather regimes associated with weak (resp. high) precipitation, wind and low (resp. high) temperatures correspond to higher (resp. lower) PM2.5 concentrations. We also observe that rain rate is the variable that impacts PM2.5 concentrations the most. Next, we search for better relationships by adding this second variable to the classification: we therefore build new weather regimes, called weather types. Because of the low number of the EMEP observations, we compute PM2.5 concentrations with the Polyphemus/Polair3D CTM for years between 2000 and 2008 in order to obtain a spatially and temporally complete dataset of PM2.5 concentrations and chemical components, which can be used to relate PM2.5 concentrations to meteorological regimes and specific variables. By classifying both a large-scale variable and a local variable that influence the PM2.5 concentrations and using gridded data of the modeled concentrations of PM2.5, we obtain a more robust analysis. The results of this work will provide the basis to predict the effects of climate change (via the evolution of weather regimes/types frequencies) on PM2.5 chemical composition and concentrations.

  19. Annual variations of carbonaceous PM2.5 in Malaysia: influence by Indonesian peatland fires

    NASA Astrophysics Data System (ADS)

    Fujii, Y.; Tohno, S.; Amil, N.; Latif, M. T.; Oda, M.; Matsumoto, J.; Mizohata, A.

    2015-12-01

    In this study, we quantified carbonaceous PM2.5 in Malaysia through annual observations of PM2.5, focusing on organic compounds derived from biomass burning. We determined organic carbon (OC), elemental carbon and concentrations of solvent-extractable organic compounds (biomarkers derived from biomass burning sources and n-alkanes). We observed seasonal variations in the concentrations of pyrolyzed OC (OP), levoglucosan (LG), mannosan (MN), galactosan, syringaldehyde, vanillic acid (VA) and cholesterol. The average concentrations of OP, LG, MN, galactosan, VA and cholesterol were higher during the southwestern monsoon season (June-September) than during the northeastern monsoon season (December-March), and these differences were statistically significant. Conversely, the syringaldehyde concentration during the southwestern monsoon season was lower. The PM2.5 OP / OC4 mass ratio allowed distinguishing the seven samples, which have been affected by the Indonesian peatland fires (IPFs). In addition, we observed significant differences in the concentrations between the Indonesian peatland fire (IPF) and other samples of many chemical species. Thus, the chemical characteristics of PM2.5 in Malaysia appeared to be significantly influenced by IPFs during the southwestern monsoon season. Furthermore, we evaluated two indicators, the vanillic acid / syringic acid (VA / SA) and LG / MN mass ratios, which have been suggested as indicators of IPFs. The LG / MN mass ratio ranged from 14 to 22 in the IPF samples and from 11 to 31 in the other samples. Thus, the respective variation ranges partially overlapped. Consequently, this ratio did not satisfactorily reflect the effects of IPFs in Malaysia. In contrast, the VA / SA mass ratio may serve as a good indicator, since it significantly differed between the IPF and other samples. However, the OP / OC4 mass ratio provided more remarkable differences than the VA / SA mass ratio, offering an even better indicator. Finally, we

  20. Lagged PM2.5 effects in mortality time series: Critical impact of covariate model

    EPA Science Inventory

    The two most common approaches to modeling the effects of air pollution on mortality are the Harvard and the Johns Hopkins (NMMAPS) approaches. These two approaches, which use different sets of covariates, result in dissimilar estimates of the effect of lagged fine particulate ma...

  1. INTEGRATED AND REAL-TIME DIFFUSION DENUDER SAMPLE FOR PM2.5. (R825367)

    EPA Science Inventory

    Abstract

    Particulate matter (PM) is a complex mixture of stable condensed phases, adsorbed or dissolved gases, and semi-volatile materials, i.e. compounds that transfer between the gas and condensed phases. Fine particles in both rural and urban environments contain su...

  2. Sandia Advanced MEMS Design Tools, Version 2.2.5

    SciTech Connect

    Yarberry, Victor; Allen, James; Lantz, Jeffery; Priddy, Brian; & Westling, Belinda

    2010-01-19

    The Sandia National Laboratories Advanced MEMS Design Tools, Version 2.2.5, is a collection of menus, prototype drawings, and executables that provide significant productivity enhancements when using AutoCAD to design MEMS components. This release is designed for AutoCAD 2000i, 2002, or 2004 and is supported under Windows NT 4.0, Windows 2000, or XP. SUMMiT V (Sandia Ultra planar Multi level MEMS Technology) is a 5 level surface micromachine fabrication technology, which customers internal and external to Sandia can access to fabricate prototype MEMS devices. This CD contains an integrated set of electronic files that: a) Describe the SUMMiT V fabrication process b) Facilitate the process of designing MEMS with the SUMMiT process (prototype file, Design Rule Checker, Standard Parts Library) New features in this version: AutoCAD 2004 support has been added. SafeExplode ? a new feature that explodes blocks without affecting polylines (avoids exploding polylines into objects that are ignored by the DRC and Visualization tools). Layer control menu ? a pull-down menu for selecting layers to isolate, freeze, or thaw. Updated tools: A check has been added to catch invalid block names. DRC features: Added username/password validation, added a method to update the user?s password. SNL_DRC_WIDTH ? a value to control the width of the DRC error lines. SNL_BIAS_VALUE ? a value use to offset selected geometry SNL_PROCESS_NAME ? a value to specify the process name Documentation changes: The documentation has been updated to include the new features. While there exist some files on the CD that are used in conjunction with software package AutoCAD, these files are not intended for use independent of the CD. Note that the customer must purchase his/her own copy of AutoCAD to use with these files.

  3. Sandia Advanced MEMS Design Tools, Version 2.2.5

    2010-01-19

    The Sandia National Laboratories Advanced MEMS Design Tools, Version 2.2.5, is a collection of menus, prototype drawings, and executables that provide significant productivity enhancements when using AutoCAD to design MEMS components. This release is designed for AutoCAD 2000i, 2002, or 2004 and is supported under Windows NT 4.0, Windows 2000, or XP. SUMMiT V (Sandia Ultra planar Multi level MEMS Technology) is a 5 level surface micromachine fabrication technology, which customers internal and external tomore » Sandia can access to fabricate prototype MEMS devices. This CD contains an integrated set of electronic files that: a) Describe the SUMMiT V fabrication process b) Facilitate the process of designing MEMS with the SUMMiT process (prototype file, Design Rule Checker, Standard Parts Library) New features in this version: AutoCAD 2004 support has been added. SafeExplode ? a new feature that explodes blocks without affecting polylines (avoids exploding polylines into objects that are ignored by the DRC and Visualization tools). Layer control menu ? a pull-down menu for selecting layers to isolate, freeze, or thaw. Updated tools: A check has been added to catch invalid block names. DRC features: Added username/password validation, added a method to update the user?s password. SNL_DRC_WIDTH ? a value to control the width of the DRC error lines. SNL_BIAS_VALUE ? a value use to offset selected geometry SNL_PROCESS_NAME ? a value to specify the process name Documentation changes: The documentation has been updated to include the new features. While there exist some files on the CD that are used in conjunction with software package AutoCAD, these files are not intended for use independent of the CD. Note that the customer must purchase his/her own copy of AutoCAD to use with these files.« less

  4. Meteorological Modes of Variability for Fine Particulate Matter (PM2.5) Air Quality in the United States: Implications for PM2.5 Sensitivity to Climate Change

    EPA Science Inventory

    We applied a multiple linear regression model to understand the relationships of PM2.5 with meteorological variables in the contiguous US and from there to infer the sensitivity of PM2.5 to climate change. We used 2004-2008 PM2.5 observations fro...

  5. Hourly elemental concentrations in PM2.5 aerosols sampled simultaneously at urban background and road site

    NASA Astrophysics Data System (ADS)

    Dall'Osto, M.; Querol, X.; Amato, F.; Karanasiou, A.; Lucarelli, F.; Nava, S.; Calzolai, G.; Chiari, M.

    2012-08-01

    Hourly-resolved aerosol chemical speciation data can be a highly powerful tool to determine the source origin of atmospheric pollutants in urban Environments. Aerosol mass concentrations of seventeen elements (Na, Mg, Al, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr and Pb) were obtained by time (1 h) and size (PM2.5 particulate matter <2.5 μm) resolved Particle Induced X-ray Emission (PIXE) measurements. In the Marie Curie FP7-EU framework of SAPUSS (Solving Aerosol Problems by Using Synergistic Strategies), the unique approach used is the simultaneous PIXE measurements at two monitoring sites: urban background (UB) and a street canyon traffic road site (RS). Elements related to primary non exhaust traffic emission (Fe, Cu), dust resuspension (Ca) and anthropogenic Cl were found enhanced at the RS, whereas industrial related trace metals (Zn, Pb, Mn) were found at higher concentrations at the more ventilated UB site. When receptor modelling was performed with positive matrix factorization (PMF), nine different aerosol sources were identified at both sites: three types of regional aerosols (secondary sulphate (S) - 27%, biomass burning (K) - 5%, sea salt (Na-Mg) - 17%), three types of dust aerosols (soil dust (Al-Ti) - 17%, urban crustal dust (Ca) - 6%, and primary traffic non exhaust brake dust (Fe-Cu) - 7%), and three types industrial aerosol plumes-like events (shipping oil combustion (V-Ni) - 17%, industrial smelters (Zn-Mn) - 3%, and industrial combustion (Pb-Cl) - 5%). The validity of the PMF solution of the PIXE data is supported by strong correlations with external single particle mass spectrometry measurements. Beside apportioning the aerosol sources, some important air quality related conclusions can be drawn about the PM2.5 fraction simultaneously measured at the UB and RS sites: (1) the regional aerosol sources impact both monitoring sites at similar concentrations regardless their different ventilation conditions; (2) by contrast, local industrial

  6. Time?

    NASA Astrophysics Data System (ADS)

    Amoroso, Richard L.

    2013-09-01

    The concept of time in the `clockwork' Newtonian world was irrelevant; and has generally been ignored until recently by several generations of physicists since the implementation of quantum mechanics. We will set aside the utility of time as a property relating to physical calculations of events relating to a metrics line element or as an aspect of the transformation of a particles motion/interaction in a coordinate system or in relation to thermodynamics etc., i.e. we will discard all the usual uses of time as a concept used to circularly define physical parameters in terms of other physical parameters; concentrating instead on time as an aspect of the fundamental cosmic topology of our virtual reality especially as it inseparably relates to the nature and role of the observer in natural science.

  7. Participation in an Intensive Longitudinal Study with Weekly Web Surveys Over 2.5 Years

    PubMed Central

    Barber, Jennifer; Kusunoki, Yasamin; Schulz, Paul

    2016-01-01

    Background Technological advances have made it easier for researchers to collect more frequent longitudinal data from survey respondents via personal computers, smartphones, and other mobile devices. Although technology has led to an increase in data-intensive longitudinal studies, little is known about attrition from such studies or the differences between respondents who complete frequently administered surveys in a timely manner, and respondents who do not. Objective We examined respondent characteristics and behaviors associated with continued and on-time participation in a population-based intensive longitudinal study, using weekly web-based survey interviews over an extended period. Methods We analyzed data from the Relationship Dynamics and Social Life study, an intensive longitudinal study that collected weekly web-based survey interviews for 2.5 years from 1003 18- and 19-year-olds to investigate factors shaping the dynamics of their sexual behavior, contraceptive use, and pregnancies. Results Ordinary least squares and logistic regression analyses showed background respondent characteristics measured at baseline were associated with the number of days respondents remained enrolled in the study, the number of interviews they completed, and the odds that they were late completing interviews. In addition, we found that changes in pregnancy-related behaviors reported in the weekly interviews were associated with late completion of interviews. Specifically, after controlling for sociodemographic, personality, contact information, and prior experience variables, we found that weekly reports such as starting to have sex (odds ratio [OR] 1.17, 95% CI 1.03-1.32, P=.01), getting a new partner (OR 1.76, 95% CI 1.53-2.03, P<.001), stopping the use of contraception (OR 1.28, 95% CI 1.10-1.49, P=.001), and having a new pregnancy (OR 5.57, 95% CI 4.26-7.29, P<.001) were significantly associated with late survey completion. However, young women who reported changes in

  8. Structural Evolution of Early-type Galaxies to z = 2.5 in CANDELS

    NASA Astrophysics Data System (ADS)

    Chang, Yu-Yen; van der Wel, Arjen; Rix, Hans-Walter; Holden, Bradford; Bell, Eric F.; McGrath, Elizabeth J.; Wuyts, Stijn; Häussler, Boris; Barden, Marco; Faber, S. M.; Mozena, Mark; Ferguson, Henry C.; Guo, Yicheng; Galametz, Audrey; Grogin, Norman A.; Kocevski, Dale D.; Koekemoer, Anton M.; Dekel, Avishai; Huang, Kuang-Han; Hathi, Nimish P.; Donley, Jennifer

    2013-08-01

    Projected axis ratio measurements of 880 early-type galaxies at redshifts 1 < z < 2.5 selected from CANDELS are used to reconstruct and model their intrinsic shapes. The sample is selected on the basis of multiple rest-frame colors to reflect low star-formation activity. We demonstrate that these galaxies as an ensemble are dust-poor and transparent and therefore likely have smooth light profiles, similar to visually classified early-type galaxies. Similar to their present-day counterparts, the z > 1 early-type galaxies show a variety of intrinsic shapes; even at a fixed mass, the projected axis ratio distributions cannot be explained by the random projection of a set of galaxies with very similar intrinsic shapes. However, a two-population model for the intrinsic shapes, consisting of a triaxial, fairly round population, combined with a flat (c/a ~ 0.3) oblate population, adequately describes the projected axis ratio distributions of both present-day and z > 1 early-type galaxies. We find that the proportion of oblate versus triaxial galaxies depends both on the galaxies' stellar mass, and—at a given mass—on redshift. For present-day and z < 1 early-type galaxies the oblate fraction strongly depends on galaxy mass. At z > 1, this trend is much weaker over the mass range explored here (1010 < M */M ⊙ < 1011), because the oblate fraction among massive (M * ~ 1011 M ⊙) was much higher in the past: 0.59 ± 0.10 at z > 1, compared to 0.20 ± 0.02 at z ~ 0.1. When combined with previous findings that the number density and sizes of early-type galaxies substantially increase over the same redshift range, this can be explained by the gradual emergence of merger-produced elliptical galaxies, at the expense of the destruction of pre-existing disks that were common among their high-redshift progenitors. In contrast, the oblate fraction among low-mass early-type galaxies (log (M */M ⊙) < 10.5) increased toward the present, from z = 0 to 0.38 ± 0.11 at z > 1 to 0

  9. Emission and profile characteristic of polycyclic aromatic hydrocarbons in PM2.5 and PM10 from stationary sources based on dilution sampling

    NASA Astrophysics Data System (ADS)

    Kong, Shaofei; Ji, Yaqin; Li, Zhiyong; Lu, Bing; Bai, Zhipeng

    2013-10-01

    The mass concentrations and profile characteristic for 18 kinds of polycyclic aromatic hydrocarbons (PAHs) in PM2.5 and PM10 from stack gases for six types of stationary sources in Shandong Province, China were studied by a dilution sampling system and GC-MS analysis method from February to March in 2010. The mass concentrations of PM2.5 and PM10 from the six types of stationary sources varied in 8.2-79.4 mg m-3 and 23.3-156.7 mg m-3, respectively. The total mass concentrations of analyzed PAHs in PM2.5 and PM10 were in the ranges of 0.40-94.35 μg m-3 and 9.16-122.91 μg m-3. The most toxic ashes were from sinter and coke oven for both PM2.5 and PM10 with high carcinogenic PAHs concentrations. BbF, Phe, NaP, BghiP, Pyr, BaP and BeP were abundant which was different from formers and one of the key reasons may be the differences of sampling methods. Diversities in PAHs compositions existed between fly ashes within PM2.5 and PM10 fractions for coke oven according to coefficient of divergence (CD) values. PAHs profiles for PM10 emitted from coke oven were different from those of other stationary sources (with CD values higher than 0.35) and for PM2.5, it was the same for sinter (with most CD values close to 0.30). There existed similar PAHs markers for fine particles emitted from stationary sources excepted for the sinter. For PM10, PAHs markers were primary 3-ring PAHs except for the coke oven with BbF, IND and BghiP as its signatures. Diagnostic ratios of BaA/(BaA + Chr), Flu/(Flu + Pyr), BaP/(BaP + BeP), BeP/BghiP and IND/(IND + BghiP) could be not well distinguished for the six types of stationary sources with the maximum/minimum ratios lower than 2 for both PM2.5 and PM10 of fly ashes which should be not used for source identification studies. The mass concentrations and source profiles of PAHs should be updated timely for size-differentiated fly ashes from various stationary sources by dilution sampling method.

  10. Higher Education or Higher Skilling?

    ERIC Educational Resources Information Center

    Muller, Steven

    1974-01-01

    Higher education may return to education for a minority, an unlikely course; concentrate on higher skilling, the road we are on today; or restore general education, the most attractive possibility, which can be implemented by restoring basic education in literacy, history, human biology, and language. (JH)

  11. Source Apportionment of PM2.5 in Beijing, China Using Organic Tracers

    NASA Astrophysics Data System (ADS)

    Zheng, M.; Cass, G. R.; Salmon, L. G.; Schauer, J. J.

    2001-12-01

    In 2000, the annual average concentration of PM2.5 measured at five air quality monitoring sites in Beijing, China was found to be 101 micrograms per cubic meter, which is significantly higher than the annual average fine particle concentrations in many North American and European urban locations. Such high concentrations of airborne fine particulate matter lead to a variety of air quality problems including severe visibility reduction. Development of an effective strategy for reducing the air pollution emissions in Beijing requires a clear understanding of the composition, concentration, and sources of these fine particles in the atmosphere. Daily average PM2.5 samples were collected simultaneously once every 6th day at five air quality monitoring stations in Beijing, China during January, April, July, and October 2000. The samples obtained each month at each site were combined as a monthly composite sample for detailed organic tracer analysis by GC/MS (gas chromatography/mass spectrometry). The concentrations of one hundred organic compounds were quantified in each composite sample, including n-alkanes, branched alkanes, cycloalkanes, n-alkanoic acids, n-alkenoic acids, PAHs (polycyclic aromatic hydrocarbons), oxy-PAHs, hopanes, steranes, alkanedioic acids, resin acids, aromatic acids as well as key molecular marker compounds. The identified organic tracers along with elemental carbon, organic carbon, Al and Si which have been previously quantified were applied in a chemical mass balance model to apportion the sources contributing to PM2.5 mass. The major sources include coal combustion, wood burning, gasoline-power vehicle exhaust, diesel exhaust, crustal material, meat cooking, vegetative detritus, as well as secondary aerosol formation. Significant seasonal variations in the source contributions to PM2.5 were observed, e.g., higher contribution from crustal material in April and higher concentration from coal combustion in January. The highest concentration of

  12. An LUR/BME Framework to Estimate PM2.5 Explained by on Road Mobile and Stationary Sources

    PubMed Central

    2015-01-01

    Knowledge of particulate matter concentrations <2.5 μm in diameter (PM2.5) across the United States is limited due to sparse monitoring across space and time. Epidemiological studies need accurate exposure estimates in order to properly investigate potential morbidity and mortality. Previous works have used geostatistics and land use regression (LUR) separately to quantify exposure. This work combines both methods by incorporating a large area variability LUR model that accounts for on road mobile emissions and stationary source emissions along with data that take into account incompleteness of PM2.5 monitors into the modern geostatistical Bayesian Maximum Entropy (BME) framework to estimate PM2.5 across the United States from 1999 to 2009. A cross-validation was done to determine the improvement of the estimate due to the LUR incorporation into BME. These results were applied to known diseases to determine predicted mortality coming from total PM2.5 as well as PM2.5 explained by major contributing sources. This method showed a mean squared error reduction of over 21.89% oversimple kriging. PM2.5 explained by on road mobile emissions and stationary emissions contributed to nearly 568 090 and 306 316 deaths, respectively, across the United States from 1999 to 2007. PMID:24387222

  13. An LUR/BME framework to estimate PM2.5 explained by on road mobile and stationary sources.

    PubMed

    Reyes, Jeanette M; Serre, Marc L

    2014-01-01

    Knowledge of particulate matter concentrations <2.5 μm in diameter (PM2.5) across the United States is limited due to sparse monitoring across space and time. Epidemiological studies need accurate exposure estimates in order to properly investigate potential morbidity and mortality. Previous works have used geostatistics and land use regression (LUR) separately to quantify exposure. This work combines both methods by incorporating a large area variability LUR model that accounts for on road mobile emissions and stationary source emissions along with data that take into account incompleteness of PM2.5 monitors into the modern geostatistical Bayesian Maximum Entropy (BME) framework to estimate PM2.5 across the United States from 1999 to 2009. A cross-validation was done to determine the improvement of the estimate due to the LUR incorporation into BME. These results were applied to known diseases to determine predicted mortality coming from total PM2.5 as well as PM2.5 explained by major contributing sources. This method showed a mean squared error reduction of over 21.89% oversimple kriging. PM2.5 explained by on road mobile emissions and stationary emissions contributed to nearly 568,090 and 306,316 deaths, respectively, across the United States from 1999 to 2007.

  14. 2,5-hexanedione altered the degradation of low-molecular-weight neurofilament in rat nerve tissues.

    PubMed

    Song, Fuyong; Zhang, Qingguo; Kou, Ruirui; Zou, Chaoshuang; Gao, Yuan; Xie, Keqin

    2012-12-01

    Occupational exposure to n-hexane produces a central-peripheral distal axonopathy, which is characterized by giant axonal swellings filled with neurofilaments (NFs). To investigate the change of NFs degradation and their possible role in n-hexane neuropathy, adult male Wistar rats were administered intraperitoneally at a dosage of 400 mg/kg/day 2,5-hexanedione (2,5-HD) for 4 weeks. The time course of low-molecular-weight neurofilament (NF-L) degradation and autophagy-related protein in rat sciatic nerves and spinal cords was determined by Western blotting. The results demonstrated that the administration of 2,5-HD inhibited NF-L degradation to an undetectable level in sciatic nerves. Furthermore, a significant reduction of NF-L degradation in spinal cords was observed in the early stage of 2,5-HD exposure. In the meantime, 2,5-HD significantly decreased the level of Beclin-1, a key autophagy-regulated protein in sciatic nerves of rats while increased the level of P62, a selective substrate of autophagy degrading pathway, which indicated a dysfunctional autophagy in rat nerve tissues. Collectively, our findings suggested that the inhibition of autophagy by 2,5-HD might be responsible for the reduction of NF-L degradation in rat sciatic nerves, and involved in the pathogenesis of 2,5-HD-induced axonopathy.

  15. 2.5D complex resistivity modeling and inversion using unstructured grids

    NASA Astrophysics Data System (ADS)

    Xu, Kaijun; Sun, Jie

    2016-04-01

    The characteristic of complex resistivity on rock and ore has been recognized by people for a long time. Generally we have used the Cole-Cole Model(CCM) to describe complex resistivity. It has been proved that the electrical anomaly of geologic body can be quantitative estimated by CCM parameters such as direct resistivity(ρ0), chargeability(m), time constant(τ) and frequency dependence(c). Thus it is very important to obtain the complex parameters of geologic body. It is difficult to approximate complex structures and terrain using traditional rectangular grid. In order to enhance the numerical accuracy and rationality of modeling and inversion, we use an adaptive finite-element algorithm for forward modeling of the frequency-domain 2.5D complex resistivity and implement the conjugate gradient algorithm in the inversion of 2.5D complex resistivity. An adaptive finite element method is applied for solving the 2.5D complex resistivity forward modeling of horizontal electric dipole source. First of all, the CCM is introduced into the Maxwell's equations to calculate the complex resistivity electromagnetic fields. Next, the pseudo delta function is used to distribute electric dipole source. Then the electromagnetic fields can be expressed in terms of the primary fields caused by layered structure and the secondary fields caused by inhomogeneities anomalous conductivity. At last, we calculated the electromagnetic fields response of complex geoelectric structures such as anticline, syncline, fault. The modeling results show that adaptive finite-element methods can automatically improve mesh generation and simulate complex geoelectric models using unstructured grids. The 2.5D complex resistivity invertion is implemented based the conjugate gradient algorithm.The conjugate gradient algorithm doesn't need to compute the sensitivity matrix but directly computes the sensitivity matrix or its transpose multiplying vector. In addition, the inversion target zones are

  16. Determination of 2-5A synthetase and 2-5A phosphodiesterase in neuroblastoma cells by analytical capillary isotachophoresis: effects of cytokines and comparison with radioenzymatic methods.

    PubMed

    Bruchelt, G; Büdenbender, M; Schmidt, K H; Birk, A; Treuner, J; Niethammer, D

    1994-01-01

    2-5A Synthetase and 2-5A phosphodiesterase were determined by analytical capillary isotachophoresis in comparison to radioenzymatic methods. By means of isotachophoretic analysis, a frequently used radioenzymatic 2-5A synthetase assay was optimized and the results of both assays were compared. Using the isotachophoretic assay the influence of interferon-related cytokines (tumor necrosis factor-alpha and interleukin-2) on 2-5A synthetase induction in neuroblastoma cells was estimated. In contrast to mononuclear blood cells, the tumor necrosis factor induced 2-5A synthetase in these cells. 2-5A Phosphodiesterase was determined using an isotachophoretic assay and a radioenzymatic method. Degradation of A2'p5'A2'p5'A (trimeric form of 2-5A core) was measured by isotachophoresis whereas degradation of a mixture of phosphorus-32 labeled 2-5A cores was registered by radioenzymatic assay. Activity of 2-5A phosphodiesterase was only insignificantly enhanced by interferon in mononuclear blood and neuroblastoma cells. In contrast to the radioenzymatic assays, an accurate determination of 2-5A synthetase as well as of 2-5A phosphodiesterase is possible using the isotachophoretic method because the reactions are followed by measuring the substrates ATP and A2'p5'A2'p5'A, respectively.

  17. Being overweight and obese: Black children ages 2-5 years.

    PubMed

    Hudson, Cindy E

    2008-01-01

    Obesity in children is a significant public health concern. The prevalence of obesity in Black preschoolers (ages 2-5 years) is slightly higher than in whites. However, by age 6, Black children experience higher obesity prevalence. The consequences to health throughout childhood and into adulthood have both medical and economic cost to individuals and society. Factors associated with obesity in preschool children are lifestyle behaviors such as diet, level of activity, culture, environment, and parental perceptions. Programs should target young Black children and their families to reduce the incidence of obesity and promoting healthy behaviors could aid in eliminating health disparities and improving quality of life. Nurses need to provide comprehensive culturally appropriate strategies at community and individual/family levels to prevent overweight and obesity in children.

  18. Analysis of the characteristics and evolution modes of PM2.5 pollution episodes in Beijing, China during 2013.

    PubMed

    Song, Ci; Pei, Tao; Yao, Ling

    2015-01-22

    Fine particulate matter (PM2.5) has been recognized as a serious hazard linked to deleterious health effects. In this study, all PM2.5 Pollution Episodes (PPEs) in Beijing during 2013 were investigated with hourly PM2.5 observations from the Olympic Sport Center site, and then their characteristics and evolution modes analysed. Results show that 80 PPEs, covering 209 days, occurred in Beijing during 2013. Average PM2.5 concentrations during PPEs were almost twice (1.86) the annual mean value, although the PPEs showed significant seasonal variations. The most hazardous PPEs tended to occur in winter, whereas PPEs with long duration occurred in autumn. The PPEs could be divided into six clusters based on their compositions of different pollution levels, which were strongly related to meteorological factors. We used series peaks of PM2.5 concentrations to analyse the evolution modes of PPEs and found that the more peaks there were within the evolution mode, the longer the duration, and the higher the average and maximum PM2.5 concentrations. Each peak within a PPE can be identified by "rise" and "fall" patterns. The "rise" patterns are widely related to relative humidity, whereas the "fall" patterns are affected principally by wind speed for one-peak PPEs and boundary layer height for multi-peak PPEs. The peak patterns cannot be explained fully by meteorological factors; however, they might also be closely related to complex and diversified human activities.

  19. Household concentrations and personal exposure of PM2.5 among urban residents using different cooking fuels.

    PubMed

    Li, Tianxin; Cao, Suzhen; Fan, Delong; Zhang, Yaqun; Wang, Beibei; Zhao, Xiuge; Leaderer, Brian P; Shen, Guofeng; Zhang, Yawei; Duan, Xiaoli

    2016-04-01

    Exposure to PM2.5 is a leading environmental risk factor for many diseases and premature deaths, arousing growing public concerns. In this study, indoor and outdoor PM2.5 concentrations were investigated during the heating and non-heating seasons in an urban area in northwest China. Personal inhalation exposure levels among different age groups were evaluated, and the difference attributable to different cooking fuels including coal, gas and electricity, was discussed. The average concentrations of PM2.5 in the kitchen and the bedroom were 125±51 and 119±64μg/m(3) during the heating season, and 80±67 and 80±50μg/m(3) during the non-heating season, respectively. Indoor PM2.5, from indoor combustion sources but also outdoor penetration, contributed to about 75% of the total PM2.5 exposure. Much higher indoor concentrations and inhalation exposure levels were found in households using coal for cooking compared to those using gas and electricity. Changing from coal to gas or electricity for cooking could result in a reduction of PM2.5 in the kitchen by 40-70% and consequently lower inhalation exposure levels, especially for children and women.

  20. Detection and quantitation of 2,5-diketopiperazines in wheat sourdough and bread.

    PubMed

    Ryan, Liam A M; Dal Bello, Fabio; Arendt, Elke K; Koehler, Peter

    2009-10-28

    Liquid chromatography mass spectrometry (LC-MS) was used to quantify the levels of the 2,5-diketopiperazines cis-cyclo(L-Leu-L-Pro) and cis-cyclo(L-Phe-L-Pro) in acidified dough and bread. Dough acidification led to a significant increase in the level of cis-cyclo(L-Leu-L-Pro) and cis-cyclo(L-Phe-L-Pro) over 48 h compared to a nonacidified dough. However, no differences were found between chemically (mix of lactic and acetic acid in the presence of antibiotics) and biologically acidified doughs. On examination of the levels of cis-cyclo(L-Leu-L-Pro) and cis-cyclo(L-Phe-L-Pro) in bread crumb and crust, it was found that temperature is the main causative agent of 2,5-diketopiperazine formation during the baking process. Bread crumb and crust contained almost 100 and 2000 times respectively the levels found in dough prior to baking. cis-Cyclo(L-Leu-L-Pro) and cis-cyclo(L-Phe-L-Pro) were also found to be at sensorally active levels in bread crust, however both 2,5-diketopiperazines were found to be below the minimum inhibitory concentration for antifungal activity in bread.