Science.gov

Sample records for composite gre sites

  1. Beyond the GRE: using a composite score to predict 
the success of Puerto Rican students in a biomedical 
PhD program.

    PubMed

    Pacheco, Wendy I; Noel, Richard J; Porter, James T; Appleyard, Caroline B

    2015-01-01

    The use and validity of the Graduate Record Examination General Test (GRE) to predict the success of graduate school applicants is heavily debated, especially for its possible impact on the selection of underrepresented minorities into science, technology, engineering, and math fields. To better identify candidates who would succeed in our program with less reliance on the GRE and grade point average (GPA), we developed and tested a composite score (CS) that incorporates additional measurable predictors of success to evaluate incoming applicants. Uniform numerical values were assigned to GPA, GRE, research experience, advanced course work or degrees, presentations, and publications. We compared the CS of our students with their achievement of program goals and graduate school outcomes. The average CS was significantly higher in those students completing the graduate program versus dropouts (p < 0.002) and correlated with success in competing for fellowships and a shorter time to thesis defense. In contrast, these outcomes were not predicted by GPA, science GPA, or GRE. Recent implementation of an impromptu writing assessment during the interview suggests the CS can be improved further. We conclude that the CS provides a broader quantitative measure that better predicts success of students in our program and allows improved evaluation and selection of the most promising candidates. PMID:25828404

  2. Beyond the GRE: Using a Composite Score to Predict 
the Success of Puerto Rican Students in a Biomedical 
PhD Program

    PubMed Central

    Pacheco, Wendy I.; Noel, Richard J.; Porter, James T.; Appleyard, Caroline B.

    2015-01-01

    The use and validity of the Graduate Record Examination General Test (GRE) to predict the success of graduate school applicants is heavily debated, especially for its possible impact on the selection of underrepresented minorities into science, technology, engineering, and math fields. To better identify candidates who would succeed in our program with less reliance on the GRE and grade point average (GPA), we developed and tested a composite score (CS) that incorporates additional measurable predictors of success to evaluate incoming applicants. Uniform numerical values were assigned to GPA, GRE, research experience, advanced course work or degrees, presentations, and publications. We compared the CS of our students with their achievement of program goals and graduate school outcomes. The average CS was significantly higher in those students completing the graduate program versus dropouts (p < 0.002) and correlated with success in competing for fellowships and a shorter time to thesis defense. In contrast, these outcomes were not predicted by GPA, science GPA, or GRE. Recent implementation of an impromptu writing assessment during the interview suggests the CS can be improved further. We conclude that the CS provides a broader quantitative measure that better predicts success of students in our program and allows improved evaluation and selection of the most promising candidates. PMID:25828404

  3. Physics GRE Practice

    NASA Astrophysics Data System (ADS)

    Ernst, David

    2008-10-01

    This session is for students to practice the physics subject matter GRE exam. Guidance on taking the exam will be given. The students will be furnished a collection of problems taken from previous exams. Students will practice a couple problems and discuss the underlying physics knowledge and strategies that relate to these problems.

  4. GRE Policies in Electrical Engineering.

    ERIC Educational Resources Information Center

    Morris, J. E.

    1987-01-01

    Describes a survey of electrical engineering education departments at 147 universities to find out if the Graduate Record Examinations (GRE) were used in the admissions process and under what conditions. Tabulates the data according to GRE requirements. Discusses the purposes of requiring the GRE in admissions. (CW)

  5. Beyond the GRE: Using a Composite Score to Predict the Success of Puerto Rican Students in a Biomedical PhD Program

    ERIC Educational Resources Information Center

    Pacheco, Wendy I.; Noel, Richard J., Jr.; Porter, James T.; Appleyard, Caroline B.

    2015-01-01

    The use and validity of the Graduate Record Examination General Test (GRE) to predict the success of graduate school applicants is heavily debated, especially for its possible impact on the selection of underrepresented minorities into science, technology, engineering, and math fields. To better identify candidates who would succeed in our program…

  6. Crystal Structure of Thermus Aquaticus Gfh1, a Gre-factor Paralog that Inhibits rather than Stimulates transcript Cleavage

    SciTech Connect

    Lamour,V.; Hogan, B.; Erie, D.; Darst, S.

    2006-01-01

    Transcription elongation in bacteria is promoted by Gre-factors, which stimulate an endogenous, endonucleolytic transcript cleavage activity of the RNA polymerase. A GreA paralog, Gfh1, present in Thermus aquaticus and Thermus thermophilus, has the opposite effect on elongation complexes, inhibiting rather than stimulating transcript cleavage. We have determined the 3.3 Angstroms-resolution X-ray crystal structure of T. aquaticus Gfh1. The structure reveals an N-terminal and a C-terminal domain with close structural similarity to the domains of GreA, but with an unexpected conformational change in terms of the orientation of the domains with respect to each other. However, structural and functional analysis suggests that when complexed with RNA polymerase, Gfh1 adopts a conformation similar to that of GreA. These results reveal considerable structural flexibility for Gfh1, and for Gre-factors in general, as suggested by structural modeling, and point to a possible role for the conformational switch in Gre-factor and Gfh1 regulation. The opposite functional effect of Gfh1 compared with GreA may be determined by three structural characteristics. First, Gfh1 lacks the basic patch present in Gre-factors that likely plays a role in anchoring the 3'-fragment of the backtracked RNA. Second, the loop at the tip of the N-terminal coiled-coil is highly flexible and contains extra acidic residues compared with GreA. Third, the N-terminal coiled-coil finger lacks a kink in the first a-helix, resulting in a straight coiled-coil compared with GreA. The latter two characteristics suggest that Gfh1 chelates a magnesium ion in the RNA polymerase active site (like GreA) but in a catalytically inactive configuration.

  7. Cliffs' GRE StudyWare Package: A Critical Evaluation.

    ERIC Educational Resources Information Center

    Brooke, Stephanie L.

    1995-01-01

    Provides evaluation of Cliffs' GRE StudyWare package (Bobrow, 1992). Discusses the educational implications of using Cliffs' approach, in addition to focusing on software considerations. Makes recommendations concerning Cliffs' method for Graduate Record Examination (GRE) preparation. (Author/LKS)

  8. The Predictive Validity of GRE Aptitude Test.

    ERIC Educational Resources Information Center

    Kaiser, Javaid

    The continued controversy concerning the predictive validity of the Graduate Record Examination (GRE) aptitude test and its influence on selection decisions, including admission and financial aid, has necessitated the establishment of local norms. The sample involved 407 University of Kansas education and computer science students. Information on…

  9. The GRE Psychology Test: A Useful but Poorly Understood Test.

    ERIC Educational Resources Information Center

    Kalat, James W.; Matlin, Margaret W.

    2000-01-01

    Provides an overview of the Graduate Record Examination (GRE) Psychology test focusing on the scoring system for the GRE Psychology test, who prepares the test and how the test is prepared, and the usefulness of the GRE Psychology test. Explores some future directions for the test. (CMK)

  10. Faculty Forum: The GRE Analytical Writing Test-- Description and Utilization

    ERIC Educational Resources Information Center

    Briihl, Deborah S.; Wasieleski, David T.

    2007-01-01

    The authors surveyed graduate programs to see how they use the Graduate Record Examination Analytic Writing (GRE-AW) Test. Only 35% of the graduate programs that responded use the GRE-AW test in their admission policy; of the programs not using it, most do not plan to do so. The programs using the GRE-AW rated it as medium or low in importance in…

  11. The Correlation Between GRE Scores and Performance in Graduate School

    NASA Astrophysics Data System (ADS)

    Morin, David

    1996-05-01

    We investigate the correlation between GRE scores and various measures of performance for graduate students in the Physics Department at Harvard University. We consider students who entered the program between 1980 and 1989. The degree to which GRE scores can predict performance is shown for different subgroups of students.

  12. Effect of Extra Time on Verbal and Quantitative GRE Scores

    ERIC Educational Resources Information Center

    Bridgeman, Brent; Cline, Frederick; Hessinger, James

    2004-01-01

    The Graduate Record Examination General Test (GRE) is a measure of academic reasoning abilities that is intended to be a power test in which speed of responding plays at most a minor role. To test this assumption, we experimentally administered both the verbal and quantitative sections of the GRE with standard time limits and with 1.5 times the…

  13. Perceptions of International Students toward Graduate Record Examination (GRE)

    ERIC Educational Resources Information Center

    Mupinga, Emily E.; Mupinga, Davison M.

    2005-01-01

    The Graduate Record Examination (GRE) is an aptitude test, thought to reflect intelligence or the capacity to learn (Larsen & Buss, 2003). It is a standardized admission exam designed to predict performance in graduate school through verbal, quantitative, and analytical reasoning questions. The GRE Board encourages graduate schools, departments,…

  14. Comparative Validity of the GRE-Analytical Test.

    ERIC Educational Resources Information Center

    Mowsesian, Richard; Hays, William L.

    The predictive validity of the revised Graduate Record Examination Analytical Test (GRE-A) was compared with the experimental form of the GRE-A, in terms of graduate school admissions as well as advancement to Ph.D. candidacy decisions. Prior to 1974 the Graduate Record Examination included just a verbal and a quantitative test; in 1974 it was…

  15. A novel dissociative steroid VBP15 reduces MUC5AC gene expression in airway epithelial cells but lacks the GRE mediated transcriptional properties of dexamethasone.

    PubMed

    Garvin, Lindsay M; Chen, Yajun; Damsker, Jesse M; Rose, Mary C

    2016-06-01

    Overproduction of secretory mucins contributes to morbidity/mortality in inflammatory lung diseases. Inflammatory mediators directly increase expression of mucin genes, but few drugs have been shown to directly repress mucin gene expression. IL-1β upregulates the MUC5AC mucin gene in part via the transcription factors NFκB while the glucocorticoid Dexamethasone (Dex) transcriptionally represses MUC5AC expression by Dex-activated GR binding to two GRE cis-sites in the MUC5AC promoter in lung epithelial cells. VBP compounds (ReveraGen BioPharma) maintain anti-inflammatory activity through inhibition of NFκB but exhibit reduced GRE-mediated transcriptional properties associated with adverse side-effects and thus have potential to minimize harmful side effects of long-term steroid therapy in inflammatory lung diseases. We investigated VBP15 efficacy as an anti-mucin agent in two types of airway epithelial cells and analyzed the transcription factor activity and promoter binding associated with VBP15-induced MUC5AC repression. VBP15 reduced MUC5AC mRNA abundance in a dose- and time-dependent manner similar to Dex in the presence or absence of IL-1β in A549 and differentiated human bronchial epithelial cells. Repression was abrogated in the presence of RU486, demonstrating a requirement for GR in the VBP15-induced repression of MUC5AC. Inhibition of NFκB activity resulted in reduced baseline expression of MUC5AC indicating that constitutive activity maintains MUC5AC production. Chromatin immunoprecipitation analysis demonstrated lack of GR and of p65 (NFκB) binding to composite GRE domains in the MUC5AC promoter following VBP15 exposure of cells, in contrast to Dex. These data demonstrate that VBP15 is a novel anti-mucin agent that mediates the reduction of MUC5AC gene expression differently than the classical glucocorticoid, Dex. PMID:27133900

  16. Highly inducible expression from vectors containing multiple GRE's in CHO cells overexpressing the glucocorticoid receptor.

    PubMed Central

    Israel, D I; Kaufman, R J

    1989-01-01

    A conditional glucocorticoid-responsive expression vector system is described for highly inducible expression of heterologous genes in mammalian cells. This host-vector system requires high level expression of the glucocorticoid receptor (GR) protein in the host cell and multiple copies of the receptor binding site within the expression vector. Transfection and selection of Chinese hamster ovary cells with expression vectors encoding the rat GR yielded cell lines which express functional receptor at high levels. Insertion of multiple copies of the MMTV enhancer (glucocorticoid responsive element, GRE) into an Adenovirus major late promoter (AdMLP) based expression vector yielded greater than 1000-fold inducible expression by dexamethasone (dex) in transient DNA transfection assays. The induced expression level was 7-fold greater than that obtained with an AdMLP based vector containing an SV40 enhancer, but lacking GRE's. Vectors containing the SV40 enhancer in combination with multiple GRE's exhibited elevated basal expression in the absence of dex, but retained inducibility in both transient assays and after integration and amplification in the CHO genome. This expression system should be of general utility for studying gene regulation and for expressing heterologous genes in a regulatable fashion. Images PMID:2546123

  17. Using Minimum Acceptable GRE Scores for Graduate Admissions Suppresses Diversity

    NASA Astrophysics Data System (ADS)

    Miller, Casey

    2014-01-01

    I will present data showing that significant performance disparities on the GRE general test exist based on the test taker's race and gender [1]. Because of the belief that high GRE scores qualify one for graduate studies, the diversity issues faced by STEM fields may originate, at least in part, in misuse of the GRE scores by graduate admissions committees. I will quantitatively demonstrate this by showing that the combination of a hard cut-off and the different score distributions leads to the systematic underrepresentation of certain groups. I will present data from USF’s PhD program that shows a lack of correlation between GRE scores and research ability; similar null results are emerging from numerous other programs. I will then discuss how assessing non-cognitive competencies in the selection process may lead to a more enlightened search for the next generation of scientists. [1] C. W. Miller, "Admissions Criteria and Diversity in Graduate School", APS News Vol 22, Issue 2, The Back Page (2013) http://www.aps.org/publications/apsnews/201302/backpage.cfm

  18. The GRE: A Barrier to Women Returning to Graduate School?

    ERIC Educational Resources Information Center

    Tisue, Linda J.; Whitaker, Dianne P.

    1999-01-01

    Discusses the Graduate Record Examination (GRE) as a possible admission barrier for women returning to graduate school, including data from an informal survey of ten universities in the southeastern United States. The validity of the exams for this population is examined, and alternatives are suggested for identifying older adult women who would…

  19. Scattering from conducting open cavities by generalized ray expansion (GRE)

    NASA Astrophysics Data System (ADS)

    Garcia-Pino, Antonio; Obelleiro, Fernando; Rodriguez, Jose L.

    1993-07-01

    The problem of electromagnetic (EM) scattering by metallic open cavities is addressed here using a generalized ray expansion (GRE) method. The wave coupled into the cavity is modeled as a combination of a number of spherical waves, the propagation of such waves being described in terms of geometrical optics (GO). A brief description of the method including some details about aperture discretization as well as results for three-dimensional problems such as circular and rectangular cross-section cavities are presented. The GRE method gives results that agree well with those of modal analysis and allow, like ray methods, for greater flexibility in geometric modeling. Furthermore, the ray-tracing process must be done only once for different incident waves, so its computational cost is lower than that of the classic ray methods, where the incoming wave is described as a different bundle of parallel rays for each direction of incidence.

  20. Turning the knots in your stomach into bows: Reappraising arousal improves performance on the GRE

    PubMed Central

    Jamieson, Jeremy P.; Mendes, Wendy Berry; Blackstock, Erin; Schmader, Toni

    2009-01-01

    This research examined the benefits of interpreting physiological arousal as a challenge response on practice and actual Graduate Record Examination (GRE) scores. Participants who were preparing to take the GRE reported to the laboratory for a practice GRE study. Participants assigned to a reappraisal condition were told arousal improves performance, whereas control participants were not given this information. We collected saliva samples at baseline and after the appraisal manipulation, which were then assayed for salivary alpha amylase (sAA), a measure of sympathetic nervous system activation. Reappraisal participants exhibited a significant increase in sAA and outperformed controls on the GRE-math section. One to three months later, participants returned to the lab and provided their score reports from their actual GRE. Again, reappraisal participants scored higher than controls on the GRE-math section. These findings illuminate the powerful influence appraisal has on physiology and performance both in and out of the laboratory. PMID:20161454

  1. Gasoline Composition Regulations Affecting LUST Sites

    EPA Science Inventory

    Passage of the Clean Air Act Amendments in 1990 imposed requirements on gasoline composition in the United States. Impacts to ground water are affected by the provisions that required oxygenated additives and limited benzene concentration. Reformulated and oxygenated gasoline w...

  2. New test data on structural behavior of GRE pipe and joint systems

    SciTech Connect

    Ma, A.; Bellamy, M.J.; Williams, S.P.

    1995-12-31

    In order to generate essential information for design purposes, a series of tests on the structural behavior of Glass Reinforced Epoxy (GRE) pipe and joint systems has now been completed. The testing program formed part of a research program, funded by the European Commission, the UK Health and Safety Executive and industry, on the development of using GRE piping systems offshore. The tests generated information on modulus of elasticity, axial strength and fatigue life for GRE pipe and joint systems. The test program and the results obtained are disseminated in this paper. The test program carries a certificate issued by Lloyd`s Register of Shipping for the suitability of GRE pipes tested.

  3. A GRE Test for the STEM Disciplines: Developing an Assessment "of" and "for" Learning

    ERIC Educational Resources Information Center

    Payne, David G.; Briel, Jacqueline B.; Hawthorn, John; Riedeburg, Karen

    2006-01-01

    Plans are described for creating a Graduate Record Examination (GRE) test for the STEM (science, technology, engineering, and mathematics) disciplines. Previous work showed that a quantitative measure for the STEM disciplines exacerbated group differences beyond those reflected in the current GRE General Test. A test development approach is…

  4. Graduate Record Examination (GRE) Scores as an Assessment Tool. AIR 1998 Annual Forum Paper.

    ERIC Educational Resources Information Center

    Underwood, David G.; Craighead, Michelle M.

    This paper examines whether graduate record examination (GRE) scores are a legitimate assessment tool for measuring institutional accountability and effectiveness that is, how well its graduates will do after having attended the institution for four or more years. Following a discussion of the various pros and cons of using the GRE as an…

  5. How Selective Are Psychology Graduate Programs? The Effect of the Selection Ratio on GRE Score Validity.

    ERIC Educational Resources Information Center

    Chernyshenko, Oleksandr S.; Ones, Deniz S.

    1999-01-01

    Examined the selection ratio for 253 doctorate-level psychology programs. Used the selection ratio to estimate the existing range restriction on the Graduate Examination (GRE) (referred to as General Record Examination) scores in validation studies. Results show that the GRE is a valid predictor of graduate school performance. (SLD)

  6. GRE as a Predictor of Graduate Student Success at a Hispanic Serving Institution of Higher Education

    ERIC Educational Resources Information Center

    Perez, Katherine

    2011-01-01

    Accurately predicting the success of graduate students is an important aspect of determining which students should be admitted into graduate programs. The GRE is a pivotal factor to examine since it is one of the most widely used criteria for graduate school admission. Even though the GRE is advertised as an accurate tool for predicting first year…

  7. A Study of the Validity of the GRE Battery in Predicting Four Criteria of Success in Doctoral Degree Programs

    ERIC Educational Resources Information Center

    Houston, Samuel H.; Strohmeyer, Eric

    1970-01-01

    Predictor variables included two Graduate Record Examination (GRE) aptitude scores, three GRE area scores, plus the GRE advanced education score. Criterion variables included: (a) grade point average; (b) graduation versus dismissal from program; (c) normative judgment analysis (JAN) rating; and (d) ipsative JAN rating. Except for normative JAN…

  8. ER–endosome contact sites: molecular compositions and functions

    PubMed Central

    Raiborg, Camilla; Wenzel, Eva M; Stenmark, Harald

    2015-01-01

    Recent studies have revealed the existence of numerous contact sites between the endoplasmic reticulum (ER) and endosomes in mammalian cells. Such contacts increase during endosome maturation and play key roles in cholesterol transfer, endosome positioning, receptor dephosphorylation, and endosome fission. At least 7 distinct contact sites between the ER and endosomes have been identified to date, which have diverse molecular compositions. Common to these contact sites is that they impose a close apposition between the ER and endosome membranes, which excludes membrane fusion while allowing the flow of molecular signals between the two membranes, in the form of enzymatic modifications, or ion, lipid, or protein transfer. Thus, ER–endosome contact sites ensure coordination of molecular activities between the two compartments while keeping their general compositions intact. Here, we review the molecular architectures and cellular functions of known ER–endosome contact sites and discuss their implications for human health. PMID:26041457

  9. Site-specific group selection drives locally adapted group compositions.

    PubMed

    Pruitt, Jonathan N; Goodnight, Charles J

    2014-10-16

    Group selection may be defined as selection caused by the differential extinction or proliferation of groups. The socially polymorphic spider Anelosimus studiosus exhibits a behavioural polymorphism in which females exhibit either a 'docile' or 'aggressive' behavioural phenotype. Natural colonies are composed of a mixture of related docile and aggressive individuals, and populations differ in colonies' characteristic docile:aggressive ratios. Using experimentally constructed colonies of known composition, here we demonstrate that population-level divergence in docile:aggressive ratios is driven by site-specific selection at the group level--certain ratios yield high survivorship at some sites but not others. Our data also indicate that colonies responded to the risk of extinction: perturbed colonies tended to adjust their composition over two generations to match the ratio characteristic of their native site, thus promoting their long-term survival in their natal habitat. However, colonies of displaced individuals continued to shift their compositions towards mixtures that would have promoted their survival had they remained at their home sites, regardless of their contemporary environment. Thus, the regulatory mechanisms that colonies use to adjust their composition appear to be locally adapted. Our data provide experimental evidence of group selection driving collective traits in wild populations. PMID:25274310

  10. Coma chemical composition at the Abydos landing site

    NASA Astrophysics Data System (ADS)

    Morse, A.; Sheridan, S.; Morgan, G.; Andrews, D.; Barber, S.; Wright, I.

    2015-10-01

    The Ptolemy instrument, onboard the Rosetta Philae Lander, made measurements of the chemical composition of the coma mid-bounce, just after the non-nominal landing on the surface, and subsequently at the Abydos landing site. This presentation will discuss Ptolemy's operations throughout this 45 hour period and the results obtained.

  11. Developing Macroinvertebrate Indicators for the Mid-continent Great Rivers: Lessons from EMAP-GRE

    EPA Science Inventory

    As part of the Environmental Monitoring and Assessment Program for Great River Ecosystems (EMAP-GRE) we developed new macroinvertebrate-assemblage based indicators of condition. In this presentation, we will summarize some of the practical and philosophical challenges encountered...

  12. Imprecise transcription termination within Escherichia coli greA leader gives rise to an array of short transcripts, GraL

    PubMed Central

    Potrykus, Katarzyna; Murphy, Helen; Chen, Xiongfong; Epstein, Jonathan A.; Cashel, Michael

    2010-01-01

    We report that greA expression is driven by two strong, overlapping P1 and P2 promoters. The P1 promoter is σ70-dependent and P2 is σE-dependent. Two-thirds of transcripts terminate within the leader region and the remaining third comprises greA mRNA. Termination efficiency seems to be unaffected by growth phase. Two collections of small 40–50 (initiating from P2) and 50–60 nt (from P1) RNA chains, termed GraL, are demonstrable in vivo and in vitro. We document that GraL arrays arise from an intrinsic terminator with an 11 bp stem followed by an AU7GCU2 sequence. Atypical chain termination occurs at multiple sites; the 3′-ends differ by 1 nt over a range of 10 nt. Transcripts observed are shown to be insensitive to Gre factors and physically released from RNAP–DNA complexes. The abundance of individual chains within each cluster displays a characteristic pattern, which can be differentially altered by oligonucleotide probes. Multiple termination sites are particularly sensitive to changes at the bottom of the stem. Evolutionarily conserved GraL stem structures and fitness assays suggest a biological function for the RNA clusters themselves. Although GraL overexpression induces ≥3-fold transcriptional changes of over 100 genes, a direct target remains elusive. PMID:20008510

  13. Comparison between optimized GRE and RARE sequences for 19F MRI studies

    NASA Astrophysics Data System (ADS)

    Soffientini, Chiara D.; Mastropietro, Alfonso; Caffini, Matteo; Cocco, Sara; Zucca, Ileana; Scotti, Alessandro; Baselli, Giuseppe; Bruzzone, Maria Grazia

    2014-03-01

    In 19F-MRI studies limiting factors are the presence of a low signal due to the low concentration of 19F-nuclei, necessary for biological applications, and the inherent low sensitivity of MRI. Hence, acquiring images using the pulse sequence with the best signal to noise ratio (SNR) by optimizing the acquisition parameters specifically to a 19F compound is a core issue. In 19F-MRI, multiple-spin-echo (RARE) and gradient-echo (GRE) are the two most frequently used pulse sequence families; therefore we performed an optimization study of GRE pulse sequences based on numerical simulations and experimental acquisitions on fluorinated compounds. We compared GRE performance to an optimized RARE sequence. Images were acquired on a 7T MRI preclinical scanner on phantoms containing different fluorinated compounds. Actual relaxation times (T1, T2, T2*) were evaluated in order to predict SNR dependence on sequence parameters. Experimental comparisons between spoiled GRE and RARE, obtained at a fixed acquisition time and in steady state condition, showed RARE sequence outperforming the spoiled GRE (up to 406% higher). Conversely, the use of the unbalanced-SSFP showed a significant increase in SNR compared to RARE (up to 28% higher). Moreover, this sequence (as GRE in general) was confirmed to be virtually insensitive to T1 and T2 relaxation times, after proper optimization, thus improving marker independence from the biological environment. These results confirm the efficacy of the proposed optimization tool and foster further investigation addressing in-vivo applicability.

  14. An Investigation of the Feasibility of Obtaining Additional Subscores on the GRE Advanced Psychology Test. GRE Board Professional Report GREB No. 74-4P.

    ERIC Educational Resources Information Center

    McPeek, Miles; And Others

    This study was undertaken to determine whether additional information useful for guidance or placement could be derived from the existing Graduate Record Examinations (GRE) Advanced Psychology Test. The number of subscores currently reported is limited by the high reliability required to make admissions decisions; subscores used only for guidance…

  15. Reducing Test Form Overlap of the GRE Subject Test in Mathematics Using IRT Triple-Part Equating. GRE Board Professional Report No. 86-14P.

    ERIC Educational Resources Information Center

    McKinley, Robert L.; Schaeffer, Gary A.

    A study was conducted to evaluate the feasibility of using item response theory (IRT) equating to reduce test form overlap of the Graduate Record Examinations (GRE) Subject Test in Mathematics. Monte Carlo methods were employed to compare double-part equating with 20-item common item blocks to triple-part equating with 10-item common item blocks.…

  16. Fitting New Measurement Models to GRE General Test Constructed-Response Item Data. GRE Board Professional Report No. 89-11P.

    ERIC Educational Resources Information Center

    Bennett, Randy Elliot; And Others

    This exploratory study applied two new cognitively sensitive measurement models to constructed-response quantitative data. The models, intended to produce qualitative characteristics of examinee performance, were fitted to algebra word problem solutions produced by 285 examinees taking the Graduate Record Examinations (GRE) General Test. The two…

  17. Diversity in Physics: Impact of Using Minimum Acceptable GRE Scores for Graduate Admissions

    NASA Astrophysics Data System (ADS)

    Miller, Casey W.

    2013-03-01

    About 180 graduate programs in physics are listed in the AIP Graduate Programs book. ~ 96% require the general GRE test; a quarter of these have an explicitly stated minimum score for admission, with the median stated cut-off being 700 (64th percentile) on GRE Quantitative; ~ 48% require the physics GRE; about half of these have an explicitly stated minimum score for admission, with the median being 600 (32nd percentile). It does not seem unreasonable to expect students to be among the top test scorers, until you dissect the test results by race and gender. In this talk, I will present data showing that the use of minimum acceptable scores on the GRE exam will have (have had?) a negative impact on diversity in Physics. I will remind the community that this practice is in opposition to ETS's Guide to the Use of Scores. I will make some suggestions for admissions committees, based in part on analyses I have performed. I will then pose challenges related to reducing the influence of GRE scores to the community, ranging from the department and university administration, to ranking bodies and professional societies. Supported by NSF.

  18. Compositions and pollutant sources of haze in Beijing urban sites.

    PubMed

    Wang, Junmei; Song, Yujun; Zuo, Jiangnan; Wu, Hongwen

    2016-05-01

    Haze from urban sites in Beijing was collected with a self-assembled electrostatic dust collector. The sizes and morphologies, thermal properties, and compositions of the particles in the haze were characterized by scanning electronic microscopy (SEM), differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), and X-ray photoelectric spectroscopy (XPS), respectively. Based on these results, the causes and pollutant sources of the chemicals in the haze were analyzed, and some countermeasures were further advanced to reduce the related pollutant sources. Graphical abstract ᅟ. PMID:26810665

  19. Identification of greA encoding a transcriptional elongation factor as a member of the carA-orf-carB-greA operon in Pseudomonas aeruginosa PAO1.

    PubMed Central

    Lu, C D; Kwon, D H; Abdelal, A T

    1997-01-01

    A homolog of the transcriptional elongation factor, GreA, was identified in Pseudomonas aeruginosa PAO1. The deduced amino acid sequence for GreA from this organism exhibits 65.2% identity to its counterpart in Escherichia coli K-12. The nucleotide sequence of greA from P. aeruginosa overlaps by four bases the 3' terminus of carB which encodes the large subunit of carbamoylphosphate synthetase. S1 nuclease experiments showed that level of the greA transcript is elevated approximately 10-fold under conditions of pyrimidine limitation, consistent with the conclusion that transcription is initiated from the previously identified pyrimidine-sensitive promoter upstream of the carA-orf-carB-greA operon. Transcriptional fusion experiments showed the presence of an additional weak promoter within the carB sequence. A greA insertional mutant of Pseudomonas aerugionsa was constructed by gene replacement. The mutant derivative grew well in rich medium but did not grow in minimal medium supplemented by arginine and nucleosides. The greA phenotype was suppressed by secondary mutations at a relatively high rate, consistent with the notion of an important physiological role for GreA. PMID:9139926

  20. Examining the Predictive Validity of GRE Scores on Doctoral Education: Students' Success and Methodology Choices in the Dissertation Process

    ERIC Educational Resources Information Center

    Rockinson-Szapkiw, Amanda J.; Bray, Oliver R., Jr.; Spaulding, Lucinda S.

    2014-01-01

    This study examines how GRE scores can be used to better understand Education doctoral candidates' methodology choices for the dissertation as well as their persistence behaviors. Candidates' of one online doctoral education program were examined. Results of a MANOVA suggested that there is no difference in GRE scores based on doctoral candidates'…

  1. Evidence Suggesting We Should Admit Students Who Score Extremely Low on GRE Subtests or the GMAT to Graduate School Programs

    ERIC Educational Resources Information Center

    Micceri, Ted

    2002-01-01

    This study sought to determine whether GRE subscores (or GMAT) could predict graduation rates in related areas (math-oriented majors for GRE quantitative, etc.) in a sample of over 9,000 graduate students at a major public research university. Because few low quantitative scores were present in math-oriented majors, an attempt was made to…

  2. The GRE Analytical Score as a Predictor for Admission to Ph.D. Candidacy: A Two Year Study.

    ERIC Educational Resources Information Center

    Mowsesian, Richard; Hays, William L.

    The purpose of this study was to test the predictive efficiency of the Graduate Record Examination Analytical (GRE-A) score when used in combination with other predictors for doctoral candidacy decisions in an educational psychology department. It was hypothesized that the GRE-A would be a more efficient predictor than faculty ratings on a…

  3. Aptamers to Escherichia coli core RNA polymerase that sense its interaction with rifampicin, sigma-subunit and GreB.

    PubMed

    Kulbachinskiy, Andrey; Feklistov, Andrey; Krasheninnikov, Igor; Goldfarb, Alex; Nikiforov, Vadim

    2004-12-01

    Bacterial RNA polymerase (RNAP) is the central enzyme of gene expression that is responsible for the synthesis of all types of cellular RNAs. The process of transcription is accompanied by complex structural rearrangements of RNAP. Despite the recent progress in structural studies of RNAP, detailed mechanisms of conformational changes of RNAP that occur at different stages of transcription remain unknown. The goal of this work was to obtain novel ligands to RNAP which would target different epitopes of the enzyme and serve as specific probes to study the mechanism of transcription and conformational flexibility of RNAP. Using in vitro selection methods, we obtained 13 classes of ssDNA aptamers against Escherichia coli core RNAP. The minimal nucleic acid scaffold (an oligonucleotide construct imitating DNA and RNA in elongation complex), rifampicin and the sigma70-subunit inhibited binding of the aptamers to RNAP core but did not affect the dissociation rate of preformed RNAP-aptamer complexes. We argue that these ligands sterically block access of the aptamers to their binding sites within the main RNAP channel. In contrast, transcript cleavage factor GreB increased the rate of dissociation of preformed RNAP-aptamer complexes. This suggested that GreB that binds RNAP outside the main channel actively disrupts RNAP-aptamer complexes by inducing conformational changes in the channel. We propose that the aptamers obtained in this work will be useful for studying the interactions of RNAP with various ligands and regulatory factors and for investigating the conformational flexibility of the enzyme. PMID:15606780

  4. Being a binding site: characterizing residue composition of binding sites on proteins.

    PubMed

    Iván, Gábor; Szabadka, Zoltán; Grolmusz, Vince

    2007-01-01

    The Protein Data Bank contains the description of more than 45,000 three-dimensional protein and nucleic-acid structures today. Started to exist as the computer-readable depository of crystallographic data complementing printed articles, the proper interpretation of the content of the individual files in the PDB still frequently needs the detailed information found in the citing publication. This fact implies that the fully automatic processing of the whole PDB is a very hard task. We first cleaned and re-structured the PDB data, then analyzed the residue composition of the binding sites in the whole PDB for frequency and for hidden association rules. Main results of the paper: (i) the cleaning and repairing algorithm (ii) redundancy elimination from the data (iii) application of association rule mining to the cleaned non-redundant data set. We have found numerous significant relations of the residue-composition of the ligand binding sites on protein surfaces, summarized in two figures. One of the classical data-mining methods for exploring implication-rules, the association-rule mining, is capable to find previously unknown residue-set preferences of bind ligands on protein surfaces. Since protein-ligand binding is a key step in enzymatic mechanisms and in drug discovery, these uncovered preferences in the study of more than 19,500 binding sites may help in identifying new binding protein-ligand pairs. PMID:18305831

  5. Differential Item Functioning of GRE Mathematics Items across Computerized and Paper-and-Pencil Testing Media

    ERIC Educational Resources Information Center

    Gu, Lixiong; Drake, Samuel; Wolfe, Edward W.

    2006-01-01

    This study seeks to determine whether item features are related to observed differences in item difficulty (DIF) between computer- and paper-based test delivery media. Examinees responded to 60 quantitative items similar to those found on the GRE general test in either a computer-based or paper-based medium. Thirty-eight percent of the items were…

  6. Subgroup Differences on the GRE Quantitative Test Based on the Underlying Cognitive Processes and Knowledge.

    ERIC Educational Resources Information Center

    Tatsuoka, Kikumi K.; Boodoo, Gwyneth M.

    This chapter describes a study adopting the findings from an investigation of the cognitive processing and knowledge requirements of individuals taking the Graduate Record Examination Quantitative (GRE-Q) Test. The study investigates subgroup differences such as major field of study, gender, and racial-ethnic backgrounds of students taking the…

  7. GRE Use among the Higher Education Community: Historical Practice Is Not Always Best Practice.

    ERIC Educational Resources Information Center

    Johnson, Troy

    2001-01-01

    Describes three areas in which the graduate community is vulnerable to substandard practice when using Graduate Record Examinations (GRE) scores in decision processes: percentile versus raw scores, cut-off scores, and summed scores. Asserts that the graduate community is generally unaware that raw scores on the verbal, quantitative, and analytical…

  8. On the Relationship Between Site Geology and the Distribution of Surface Regolith Compositions at the Apollo Sites

    NASA Technical Reports Server (NTRS)

    Korotev, Randy L.

    2000-01-01

    Some considerations are discussed on how information on site geology can be obtained from the distribution of data points on 2-element plots of composition of lunar regolith samples collected along a traverse.

  9. Control of transcription elongation by GreA determines rate of gene expression in Streptococcus pneumoniae.

    PubMed

    Yuzenkova, Yulia; Gamba, Pamela; Herber, Martijn; Attaiech, Laetitia; Shafeeq, Sulman; Kuipers, Oscar P; Klumpp, Stefan; Zenkin, Nikolay; Veening, Jan-Willem

    2014-01-01

    Transcription by RNA polymerase may be interrupted by pauses caused by backtracking or misincorporation that can be resolved by the conserved bacterial Gre-factors. However, the consequences of such pausing in the living cell remain obscure. Here, we developed molecular biology and transcriptome sequencing tools in the human pathogen Streptococcus pneumoniae and provide evidence that transcription elongation is rate-limiting on highly expressed genes. Our results suggest that transcription elongation may be a highly regulated step of gene expression in S. pneumoniae. Regulation is accomplished via long-living elongation pauses and their resolution by elongation factor GreA. Interestingly, mathematical modeling indicates that long-living pauses cause queuing of RNA polymerases, which results in 'transcription traffic jams' on the gene and thus blocks its expression. Together, our results suggest that long-living pauses and RNA polymerase queues caused by them are a major problem on highly expressed genes and are detrimental for cell viability. The major and possibly sole function of GreA in S. pneumoniae is to prevent formation of backtracked elongation complexes. PMID:25190458

  10. Control of transcription elongation by GreA determines rate of gene expression in Streptococcus pneumoniae

    PubMed Central

    Yuzenkova, Yulia; Gamba, Pamela; Herber, Martijn; Attaiech, Laetitia; Shafeeq, Sulman; Kuipers, Oscar P.; Klumpp, Stefan; Zenkin, Nikolay; Veening, Jan-Willem

    2014-01-01

    Transcription by RNA polymerase may be interrupted by pauses caused by backtracking or misincorporation that can be resolved by the conserved bacterial Gre-factors. However, the consequences of such pausing in the living cell remain obscure. Here, we developed molecular biology and transcriptome sequencing tools in the human pathogen Streptococcus pneumoniae and provide evidence that transcription elongation is rate-limiting on highly expressed genes. Our results suggest that transcription elongation may be a highly regulated step of gene expression in S. pneumoniae. Regulation is accomplished via long-living elongation pauses and their resolution by elongation factor GreA. Interestingly, mathematical modeling indicates that long-living pauses cause queuing of RNA polymerases, which results in ‘transcription traffic jams’ on the gene and thus blocks its expression. Together, our results suggest that long-living pauses and RNA polymerase queues caused by them are a major problem on highly expressed genes and are detrimental for cell viability. The major and possibly sole function of GreA in S. pneumoniae is to prevent formation of backtracked elongation complexes. PMID:25190458

  11. The Consequences of Physics GRE Requirements for Graduate School: A Case Study at UT Austin

    NASA Astrophysics Data System (ADS)

    Siders, Jennifer L. W.

    1996-05-01

    Five years ago the Physics Department at the University of Texas at Austin began requiring a 700 on the Physics GRE for admission to Ph.D. Candidacy. This requirement eventually led the admissions committee to use an unofficial requirement of 600 for graduate admissions because of the difficulty students had bringing up their scores. Shortly thereafter, we noticed a dramatic drop in the number of women graduate students entering our department. Three years worth of data from American applicants to the UT Physics department was analyzed (31 women, 363 men). The 600 cutoff eliminated 55 percent of the female applicants and 24 percent of male applicants. Only 10 percent of the women applicants had over a 700 while 47 percent of the male applicants had already achieved a score higher than 700. The average Physics GRE score for male applicants was 100 points higher than the average female applicants score. The correlation between undergraduate GPA and Physics GRE score is very small. 97 percent of the female applicants and 90 percent of the male applicants had GPA's over a 3.00. We will discuss our results and the changes that were made at UT.

  12. The Greek Database of Seismogenic Sources (GreDaSS): the new version.

    NASA Astrophysics Data System (ADS)

    Caputo, Riccardo; Pavlides, Spyros; GreDaSS Working Group

    2014-05-01

    The Greek Database of Seismogenic Sources (GreDaSS) is a repository of geological, tectonic and active fault data for the Greek territory and its surroundings including sectors of western Anatolia, southern Bulgaria, FYR of Macedonia and Albania. The principal aim of this international project is to create a homogenized framework of all data relevant to the seismotectonics, and especially the seismic hazard assessment, of Greece and its surroundings as well as a common research platform for performing seismic hazard analyses, modelling and scenarios from specific seismogenic structures. GreDaSS represents an on-going project based on the results of decades of investigations by the GreDaSS Working Group* and by numerous other researchers working on the active tectonics of the broader Aegean Region. Members of the WG have contributed in several national and European projects like FAUST (Faults as a seismological tool, 1998-2000) and SHARE (Seismic Hazard and Armonization in Europe, 2009-2012). The database is continuously updated by the WG, with the aim of improving its completeness in terms of seismogenic sources analysed and included, but also of enriching and better defining all parametric and ancillary information on each source. Preliminary and partial versions of GreDaSS have been already presented at previous congresses (Pavlides et al., 2010; Caputo et al., 2012; Sboras et al., 2013), but at next EGU the whole area and the most recent version of the database will be displayed. *) the principal scientific contributors belonging to the GreDaSS WG are: Sboras. S., Chatzipetros A., Koukouvelas I., Michailidou A., Valkaniotis S., Tarabusi G. Caputo R., Chatzipetros A., Pavlides S. and Sboras S. (2012): Ann. Geophysics, 55(5), 859-894, doi: 10.4401/ag-5168 Pavlides S., Caputo R., Sboras S., Chatzipetros A., Papathanasiou G. & Valkaniotis S. (2010): Bull. Geol. Soc. Greece, 43(1), 486-494 Sboras S., Pavlides S., Caputo R., Chatzipetros A., Michailidou A

  13. Women, Minorities, and Admissions Testing: The SAT II and GRE Physics Tests

    NASA Astrophysics Data System (ADS)

    Zolandz, A. M.

    1996-05-01

    The differences in average scores on standardized assessments between gender and minority subgroups of examinees is a continuing concern, both for Educational Testing Service (ETS) and the organizations that sponsor the assessments developed at ETS. The test development and analysis procedures used by ETS will be described, with an emphasis on those related to the fairness of the assessments for all subgroups and the understanding of the diffferences in performance among the groups. Relevant information for the SAT II and GRE Physics tests will be presented and discussed.

  14. Narrowing the Pipeline: The SAT and GRE General Tests as Arbitrary Gatekeepers

    NASA Astrophysics Data System (ADS)

    Zappardino, Pamela

    1996-05-01

    Before the stage of taking more specialized standardized exams (with their attendant problems) is reached, scores on the SAT and/or GRE general tests eliminate or discourage many capable students from entering specific programs of study. The artificial bottleneck that this creates and the disparate impact that the use of these tests as gatekeepers has on qualified women, minority group members and low-income students will be described. Implications of this process for diversifying the pool of graduate students in physics will be discussed.

  15. Measurements of fog composition at a rural site

    NASA Astrophysics Data System (ADS)

    Straub, Derek J.; Hutchings, James W.; Herckes, Pierre

    2012-02-01

    Studies that focus on fog chemistry in the United States have been limited to relatively few locations. Apart from measurements along the East and West coasts and extensive analysis of radiation fog in the Central Valley of California, fog composition has been characterized in only a handful of other locations. To complement and expand the existing fog chemistry data that are currently available, a new field campaign was established at a rural location in Central Pennsylvania to produce a unique, long term record of fog composition. From 2007 to 2010, 41 fog events were sampled with an automated Caltech Heated Rod Cloudwater Collector (CHRCC). The collected samples were analyzed primarily for pH and major inorganic ions. Dissolved organic carbon (DOC) and trace metals were analyzed in selected samples and N-nitrosodimethylamine (NDMA) was quantified in two samples. Sample composition varied widely during the study period. Sulfate concentrations ranged from 15 to 955 (median = 123) μN and pH varied between 3.08 and 7.41 (median = 5.77). In terms of volume weighted averages, ammonium was the most abundant ionic species followed by sulfate, calcium, and nitrate. For the subset of samples in which DOC was analyzed, concentrations ranged from 2.2 to 22.6 mgC l -1. Comparisons with regional precipitation chemistry measurements reveal the influence of local agricultural and soil sources on fog composition. The sum of sulfate, nitrate, and ammonium measured in the present study is considerably lower than the majority of radiation, precipitation, and coastal fogs collected in the United States although the ammonium/(nitrate + sulfate) ratio is similar to those found in the Central Valley of California.

  16. The Grenoble Analysis Toolkit (GreAT)-A statistical analysis framework

    NASA Astrophysics Data System (ADS)

    Putze, A.; Derome, L.

    2014-12-01

    The field of astroparticle physics is currently the focus of prolific scientific activity. In the last decade, this field has undergone significant developments thanks to several experimental results from CREAM, PAMELA, Fermi, and H.E.S.S. Moreover, the next generation of instruments, such as AMS-02 (launched on 16 May 2011) and CTA, will undoubtedly facilitate more sensitive and precise measurements of the cosmic-ray and γ-ray fluxes. To fully exploit the wealth of high precision data generated by these experiments, robust and efficient statistical tools such as Markov Chain Monte Carlo algorithms or evolutionary algorithms, able to handle the complexity of joint parameter spaces and datasets, are necessary for a phenomenological interpretation. The Grenoble Analysis Toolkit (GreAT) is an user-friendly and modular object orientated framework in C++, which samples the user-defined parameter space with a pre- or user-defined algorithm. The functionality of GreAT is presented in the context of cosmic-ray physics, where the boron-to-carbon (B/C) ratio is used to constrain cosmic-ray propagation models.

  17. GRE2 from Scheffersomyces stipitis as an aldehyde reductase contributes tolerance to aldehyde inhibitors derived from lignocellulosic biomass.

    PubMed

    Wang, Xu; Ma, Menggen; Liu, Z Lewis; Xiang, Quanju; Li, Xi; Liu, Na; Zhang, Xiaoping

    2016-08-01

    Scheffersomyces (Pichia) stipitis is one of the most promising yeasts for industrial bioethanol production from lignocellulosic biomass. S. stipitis is able to in situ detoxify aldehyde inhibitors (such as furfural and 5-hydroxymethylfurfural (HMF)) to less toxic corresponding alcohols. However, the reduction enzymes involved in this reaction remain largely unknown. In this study, we reported that an uncharacterized open reading frame PICST_72153 (putative GRE2) from S. stipitis was highly induced in response to furfural and HMF stresses. Overexpression of this gene in Saccharomyces cerevisiae improved yeast tolerance to furfural and HMF. GRE2 was identified as an aldehyde reductase which can reduce furfural to FM with either NADH or NADPH as the co-factor and reduce HMF to FDM with NADPH as the co-factor. This enzyme can also reduce multiple aldehydes to their corresponding alcohols. Amino acid sequence analysis indicated that it is a member of the subclass "intermediate" of the short-chain dehydrogenase/reductase (SDR) superfamily. Although GRE2 from S. stipitis is similar to GRE2 from S. cerevisiae in a three-dimensional structure, some differences were predicted. GRE2 from S. stipitis forms loops at D133-E137 and T143-N145 locations with two α-helices at E154-K157 and E252-A254 locations, different GRE2 from S. cerevisiae with an α-helix at D133-E137 and a β-sheet at T143-N145 locations, and two loops at E154-K157 and E252-A254 locations. This research provided guidelines for the study of other SDR enzymes from S. stipitis and other yeasts on tolerant mechanisms to aldehyde inhibitors derived from lignocellulosic biomass. PMID:27003269

  18. Atomic level understanding of site-specific interactions in Polyaniline/TiO2 composite

    NASA Astrophysics Data System (ADS)

    Chabungbam, Satyananda; Loh, G. C.; Sahariah, Munima B.; Pal, Arup R.; Pandey, Ravindra

    2016-02-01

    Spin-polarized density functional theory calculations have been performed to understand the interactions in polyaniline (PAni) and TiO2 composite at the atomic level. Binding energy calculation shows that composite structure is energetically more stable when Ti atom of TiO2 sits on top of PAni. It is also found that there is a dependency of the CBM on the site of TiO2 interaction in this composite system. The results suggest that optimization of the synthesis parameters at atomic level can be an effective way to improve the performance of a photovoltaic device based on PAni-TiO2 composite.

  19. The Performance of Native Speakers of English and ESL Speakers on the Computer-based TOEFL and GRE General Test

    ERIC Educational Resources Information Center

    Stricker, L. J.

    2004-01-01

    The purpose of this study was to replicate previous research on the construct validity of the paper-based version of the TOEFL and extend it to the computer-based TOEFL. Two samples of Graduate Record Examination (GRE) General Test-takers were used: native speakers of English specially recruited to take the computer-based TOEFL, and ESL…

  20. A Five-Year Analysis of GRE, Race, Gender, and Undergraduate GPA as Predictors of State Certification Examination Results.

    ERIC Educational Resources Information Center

    Wilmore, Elaine L.; McNeil, Jesse Jai, Jr.

    This study addressed the factors of Graduate Record Examination scores (GRE), race, gender, and undergraduate grade point average (GPA) as predictors of success on the Texas state administrator certification examination. The paper was presented as the entry point for expected discussion of the effects of high stakes accountability policies on the…

  1. Geographic and Operational Site Parameters List (GOSPL) for the 2004 Composite Analysis

    SciTech Connect

    Last, George V.; Nichols, William E.; Kincaid, Charles T.

    2004-07-01

    This report briefly describes each of the key data fields, including the source(s) of data, and provides the resulting inputs to be used for the 2004 Composite Analysis. A master spreadsheet termed the Geographic and Operational Site Parameters List (GOSPL) was assembled to facilitate the generation of keyword input files containing general information on each waste site, its operational/disposal history, and its environmental settings (past, current, and future).

  2. Studies of phase composition of contact sites of diamond crystals and the surrounding rocks

    NASA Astrophysics Data System (ADS)

    Skvortsova, V. L.; Samoylovich, M. I.; Belyanin, A. F.

    2015-11-01

    The composition, structure, and morphology of iron-containing diamond-kimberlite contact sites were studied by means of scanning electron microscopy and Raman spectroscopy. The data obtained confirm the hypothesis of the similarity of mechanisms of diamond formation in nature and in experiments.

  3. Variation in the Composition and In Vitro Proinflammatory Effect of Urban Particulate Matter from Different Sites

    PubMed Central

    Manzano-León, Natalia; Quintana, Raúl; Sánchez, Brisa; Serrano, Jesús; Vega, Elizabeth; Vázquez-López, Inés; Rojas-Bracho, Leonora; López-Villegas, Tania; O’Neill, Marie S.; Vadillo-Ortega, Felipe; De Vizcaya-Ruiz, Andrea; Rosas, Irma

    2015-01-01

    Spatial variation in particulate matter–related health and toxicological outcomes is partly due to its composition. We studied spatial variability in particle composition and induced cellular responses in Mexico City to complement an ongoing epidemiologic study. We measured elements, endotoxins, and polycyclic aromatic hydrocarbons in two particle size fractions collected in five sites. We compared the in vitro proinflammatory response of J774A.1 and THP-1 cells after exposure to particles, measuring subsequent TNFα and IL-6 secretion. Particle composition varied by site and size. Particle constituents were subjected to principal component analysis, identifying three components: C1 (Si, Sr, Mg, Ca, Al, Fe, Mn, endotoxin), C2 (polycyclic aromatic hydrocarbons), and C3 (Zn, S, Sb, Ni, Cu, Pb). Induced TNFα levels were higher and more heterogeneous than IL-6 levels. Cytokines produced by both cell lines only correlated with C1, suggesting that constituents associated with soil induced the inflammatory response and explain observed spatial differences. PMID:23335408

  4. Composite Analysis for the Area 5 Radioactive Waste Management Site at the Nevada Test Site, Nye County, Nevada

    SciTech Connect

    V. Yucel

    2001-09-01

    This report summarizes the results of a Composite Analysis (CA) for the Area 5 Radioactive Waste Management Site (RWMS). The Area 5 RWMS is a US Department of Energy (DOE)-operated low-level radioactive waste (LLW) management site located in northern Frenchman Flat on the Nevada Test Site (NTS). The Area 5 RWMS has disposed of low-level radioactive waste in shallow unlined pits and trenches since 1960. Transuranic waste (TRU) and high-specific activity waste was disposed in Greater Confinement Disposal (GCD) boreholes from 1983 to 1989. The purpose of this CA is to determine if continuing operation of the Area 5 RWMS poses an acceptable or unacceptable risk to the public considering the total waste inventory and all other interacting sources of radioactive material in the vicinity. Continuing operation of the Area 5 RWMS will be considered acceptable if the total effective dose equivalent (TEDE) is less than 100 mrem in a year. If the TEDE exceeds 30 mrem in a year, a cost-benefit options analysis must be performed to determine if cost-effective management options exist to reduce the dose further. If the TEDE is found to be less than 30 mrem in a year, an analysis may be performed if warranted to determine if doses are as low as reasonably achievable (ALARA).

  5. Synthesis of supported bimetallic nanoparticles with controlled size and composition distributions for active site elucidation

    SciTech Connect

    Hakim, Sikander H.; Sener, Canan; Alba Rubio, Ana C.; Gostanian, Thomas M.; O'neill, Brandon J; Ribeiro, Fabio H.; Miller, Jeffrey T.; Dumesic, James A

    2015-08-01

    Elucidation of active sites in supported bimetallic catalysts is complicated by the high level of dispersity in the nanoparticle size and composition that is inherent in conventional methods of catalyst preparation. We present a synthesis strategy that leads to highly dispersed, bimetallic nanoparticles with uniform particle size and composition by means of controlled surface reactions. We demonstrate the synthesis of three systems, RhMo, PtMo, and RhRe, consisting of a highly reducible metal with an oxophilic promoter. These catalysts are characterized by FTIR, CO chemisorption, STEM/EDS, TPR, and XAS analysis. The catalytic properties of these bimetallic nanoparticles were probed for the selective CO hydrogenolysis of (hydroxymethyl)tetrahydropyran to produce 1,6 hexanediol. Based on the characterization results and reactivity trends, the active sites in the hydrogenolysis reaction are identified to be small ensembles of the more noble metal (Rh, Pt) adjacent to highly reduced moieties of the more oxophilic metal (Mo, Re).

  6. Aerosol measurements at a high-elevation site: composition, size, and cloud condensation nuclei activity

    SciTech Connect

    Friedman, Beth; Zelenyuk, Alla; Beranek, Josef; Kulkarni, Gourihar R.; Pekour, Mikhail S.; Hallar, Anna G.; McCubbin, Ian; Thornton, Joel A.; Cziczo, D. J.

    2013-12-09

    We present measurements of CCN concentrations and associated aerosol composition and size properties at a high-elevation research site in March 2011. CCN closure and aerosol hygroscopicity were assessed using simplified assumptions of bulk aerosol properties as well as a new method utilizing single particle composition and size to assess the importance of particle mixing state in CCN activation. Free troposphere analysis found no significant difference between the CCN activity of free tropospheric aerosol and boundary layer aerosol at this location. Closure results indicate that using only size and number information leads to adequate prediction, in the majority of cases within 50%, of CCN concentrations, while incorporating the hygroscopicity parameters of the individual aerosol components measured by single particle mass spectrometry adds to the agreement, in most cases within 20%, between predicted and measured CCN concentrations. For high-elevation continental sites, with largely aged aerosol and low amounts of local area emissions, a lack of chemical knowledge and hygroscopicity may not hinder models in predicting CCN concentrations. At sites influenced by fresh emissions or more heterogeneous particle types, single particle composition information may be more useful in predicting CCN concentrations and understanding the importance of particle mixing state on CCN activation.

  7. Correlated compositional and mineralogical investigations at the Chang'e-3 landing site

    NASA Astrophysics Data System (ADS)

    Ling, Zongcheng; Jolliff, Bradley L.; Wang, Alian; Li, Chunlai; Liu, Jianzhong; Zhang, Jiang; Li, Bo; Sun, Lingzhi; Chen, Jian; Xiao, Long; Liu, Jianjun; Ren, Xin; Peng, Wenxi; Wang, Huanyu; Cui, Xingzhu; He, Zhiping; Wang, Jianyu

    2015-12-01

    The chemical compositions of relatively young mare lava flows have implications for the late volcanism on the Moon. Here we report the composition of soil along the rim of a 450-m diameter fresh crater at the Chang'e-3 (CE-3) landing site, investigated by the Yutu rover with in situ APXS (Active Particle-induced X-ray Spectrometer) and VNIS (Visible and Near-infrared Imaging Spectrometer) measurements. Results indicate that this region's composition differs from other mare sample-return sites and is a new type of mare basalt not previously sampled, but consistent with remote sensing. The CE-3 regolith derived from olivine-normative basaltic rocks with high FeO/(FeO+MgO). Deconvolution of the VNIS data indicates abundant high-Ca ferropyroxene (augite and pigeonite) plus Fe-rich olivine. We infer from the regolith composition that the basaltic source rocks formed during late-stage magma-ocean differentiation when dense ferropyroxene-ilmenite cumulates sank and mixed with deeper, relatively ferroan olivine and orthopyroxene in a hybridized mantle source.

  8. Correlated compositional and mineralogical investigations at the Chang'e-3 landing site.

    PubMed

    Ling, Zongcheng; Jolliff, Bradley L; Wang, Alian; Li, Chunlai; Liu, Jianzhong; Zhang, Jiang; Li, Bo; Sun, Lingzhi; Chen, Jian; Xiao, Long; Liu, Jianjun; Ren, Xin; Peng, Wenxi; Wang, Huanyu; Cui, Xingzhu; He, Zhiping; Wang, Jianyu

    2015-01-01

    The chemical compositions of relatively young mare lava flows have implications for the late volcanism on the Moon. Here we report the composition of soil along the rim of a 450-m diameter fresh crater at the Chang'e-3 (CE-3) landing site, investigated by the Yutu rover with in situ APXS (Active Particle-induced X-ray Spectrometer) and VNIS (Visible and Near-infrared Imaging Spectrometer) measurements. Results indicate that this region's composition differs from other mare sample-return sites and is a new type of mare basalt not previously sampled, but consistent with remote sensing. The CE-3 regolith derived from olivine-normative basaltic rocks with high FeO/(FeO+MgO). Deconvolution of the VNIS data indicates abundant high-Ca ferropyroxene (augite and pigeonite) plus Fe-rich olivine. We infer from the regolith composition that the basaltic source rocks formed during late-stage magma-ocean differentiation when dense ferropyroxene-ilmenite cumulates sank and mixed with deeper, relatively ferroan olivine and orthopyroxene in a hybridized mantle source. PMID:26694712

  9. Correlated compositional and mineralogical investigations at the Chang′e-3 landing site

    PubMed Central

    Ling, Zongcheng; Jolliff, Bradley L.; Wang, Alian; Li, Chunlai; Liu, Jianzhong; Zhang, Jiang; Li, Bo; Sun, Lingzhi; Chen, Jian; Xiao, Long; Liu, Jianjun; Ren, Xin; Peng, Wenxi; Wang, Huanyu; Cui, Xingzhu; He, Zhiping; Wang, Jianyu

    2015-01-01

    The chemical compositions of relatively young mare lava flows have implications for the late volcanism on the Moon. Here we report the composition of soil along the rim of a 450-m diameter fresh crater at the Chang′e-3 (CE-3) landing site, investigated by the Yutu rover with in situ APXS (Active Particle-induced X-ray Spectrometer) and VNIS (Visible and Near-infrared Imaging Spectrometer) measurements. Results indicate that this region's composition differs from other mare sample-return sites and is a new type of mare basalt not previously sampled, but consistent with remote sensing. The CE-3 regolith derived from olivine-normative basaltic rocks with high FeO/(FeO+MgO). Deconvolution of the VNIS data indicates abundant high-Ca ferropyroxene (augite and pigeonite) plus Fe-rich olivine. We infer from the regolith composition that the basaltic source rocks formed during late-stage magma-ocean differentiation when dense ferropyroxene-ilmenite cumulates sank and mixed with deeper, relatively ferroan olivine and orthopyroxene in a hybridized mantle source. PMID:26694712

  10. Long-term changes in species composition and relative abundances of sharks at a provisioning site.

    PubMed

    Brunnschweiler, Juerg M; Abrantes, Kátya G; Barnett, Adam

    2014-01-01

    Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today's recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-species shark feeding site in Fiji. Using direct observation sampling methods, eight species of sharks (bull shark Carcharhinus leucas, grey reef shark Carcharhinus amblyrhynchos, whitetip reef shark Triaenodon obesus, blacktip reef shark Carcharhinus melanopterus, tawny nurse shark Nebrius ferrugineus, silvertip shark Carcharhinus albimarginatus, sicklefin lemon shark Negaprion acutidens, and tiger shark Galeocerdo cuvier) displayed inter-annual site fidelity between 2003 and 2012. Encounter rates and/or relative abundances of some species changed over time, overall resulting in more individuals (mostly C. leucas) of fewer species being encountered on average on shark feeding dives at the end of the study period. Differences in shark community composition between the years 2004-2006 and 2007-2012 were evident, mostly because N. ferrugineus, C. albimarginatus and N. acutidens were much more abundant in 2004-2006 and very rare in the period of 2007-2012. Two explanations are offered for the observed changes in relative abundances over time, namely inter-specific interactions and operator-specific feeding protocols. Both, possibly in combination, are suggested to be important determinants of species composition and encounter rates, and relative abundances at this shark provisioning site in Fiji. This study, which includes the most species from a spatially confined shark provisioning site to date, suggests that long-term provisioning may result in competitive exclusion among shark

  11. Long-Term Changes in Species Composition and Relative Abundances of Sharks at a Provisioning Site

    PubMed Central

    Brunnschweiler, Juerg M.; Abrantes, Kátya G.; Barnett, Adam

    2014-01-01

    Diving with sharks, often in combination with food baiting/provisioning, has become an important product of today’s recreational dive industry. Whereas the effects baiting/provisioning has on the behaviour and abundance of individual shark species are starting to become known, there is an almost complete lack of equivalent data from multi-species shark diving sites. In this study, changes in species composition and relative abundances were determined at the Shark Reef Marine Reserve, a multi-species shark feeding site in Fiji. Using direct observation sampling methods, eight species of sharks (bull shark Carcharhinus leucas, grey reef shark Carcharhinus amblyrhynchos, whitetip reef shark Triaenodon obesus, blacktip reef shark Carcharhinus melanopterus, tawny nurse shark Nebrius ferrugineus, silvertip shark Carcharhinus albimarginatus, sicklefin lemon shark Negaprion acutidens, and tiger shark Galeocerdo cuvier) displayed inter-annual site fidelity between 2003 and 2012. Encounter rates and/or relative abundances of some species changed over time, overall resulting in more individuals (mostly C. leucas) of fewer species being encountered on average on shark feeding dives at the end of the study period. Differences in shark community composition between the years 2004–2006 and 2007–2012 were evident, mostly because N. ferrugineus, C. albimarginatus and N. acutidens were much more abundant in 2004–2006 and very rare in the period of 2007–2012. Two explanations are offered for the observed changes in relative abundances over time, namely inter-specific interactions and operator-specific feeding protocols. Both, possibly in combination, are suggested to be important determinants of species composition and encounter rates, and relative abundances at this shark provisioning site in Fiji. This study, which includes the most species from a spatially confined shark provisioning site to date, suggests that long-term provisioning may result in competitive exclusion

  12. Chemical composition and mass closure of ambient PM10 at urban sites

    NASA Astrophysics Data System (ADS)

    Terzi, Eleni; Argyropoulos, George; Bougatioti, Aikaterini; Mihalopoulos, Nikolaos; Nikolaou, Kostas; Samara, Constantini

    2010-06-01

    The chemical composition of PM10 was studied during summer and winter sampling campaigns conducted at two different urban sites in the city of Thessaloniki, Greece (urban-traffic, UT and urban-industrial, UI). PM10 samples were chemically analysed for minerals (Si, Al, Ca, Mg, Fe, Ti, K), trace elements (Cd, Cr, Cu, Mn, Pb, V, Zn, Te, Co, Ni, Se, Sr, As, and Sb), water-soluble ions (Cl -, NO 3-, SO 42-, Na +, K +, NH 4+, Ca 2+, Mg 2+) and carbonaceous compounds (OC, EC). Spatial variations of atmospheric concentrations showed significantly higher levels of minerals, some trace metals and TC at the UI site, while at the UT site significantly higher levels of elements like Cd, Ba, Sn, Sb and Te were observed. Crustal elements, excepting Ca at the UI site, did not exhibit significant seasonal variations at any site pointing to constant emissions throughout the year. In order to reconstruct the particle mass, the determined components were classified into six classes as follows: mineral matter (MIN), trace elements (TE), organic matter (OM), elemental carbon (EC), sea salt (SS) and secondary inorganic aerosol (SIA). Good correlations with slopes close to 1 were found between chemically determined and gravimetrically measured PM10 masses for both sites. According to the chemical mass closure obtained, the major components of PM10 at both sites were MIN (soil-derived compounds), followed by OM and SIA. The fraction unaccounted for by chemical analysis comprised on average 8% during winter and 15% during summer at the urban-industrial site, while at the urban-traffic site the percentages were 21.5% in winter and 4.8% in summer.

  13. Quasi-static and multi-site high velocity impact response of composite structures

    NASA Astrophysics Data System (ADS)

    Deka, Lakshya

    Understanding of low and high velocity transverse impact of laminated fiber reinforced composites is of interest in military, aerospace, marine and civilian structures. Recent advances in the field of numerical simulation provide a means of predicting the performance characteristics of layered materials for impact protection. The overall objective of this work is to investigate the behavior of laminated composites which include both thermoplastic and thermoset systems subjected to quasi-static, low and high velocity impact; both from an experimental and numerical modeling view point. To analyze this problem, a series of quasi-static, low and high velocity impact tests have been performed on laminated composite plates namely E-glass/polypropylene, S2-glass/epoxy and carbon/polyphenylene sulphide. To analyze the perforation mechanism, ballistic limit and damage evolution, an explicit three-dimensional finite element code LS-DYNA is used. Selecting proper material models and contact definition is one of the major criteria for obtaining accurate numerical simulation. Material model 162 (MAT 162), a progressive failure model based on modified Hashin's criteria and continuum damage mechanics (CDM) has been assigned to predict failure of the laminate. This approach is used because during transverse impact, a composite laminate undergoes progressive damage. The laminate and the projectile are meshed using brick elements with single integration points. The impact velocity ranges from 180 to 400 m s -1. This work focuses on three main aspects; (i) To obtain static and dynamic material properties to incorporate into the finite element model and predict the ballistic limit of a composite laminate based on the information from quasi-static punch shear test; (ii) To understand penetration, material erosion, ballistic limit and delamination mechanisms for single and multi-site high velocity (or ballistic) impact of composite laminates; (iii) To investigate the different failure

  14. Analysis of elemental composition of porcelains unearthed from Waguantan kiln site by PIXE-RBS

    NASA Astrophysics Data System (ADS)

    Zhou, Z.; Zhang, K.; Xia, C. D.; Liu, M. T.; Zhu, J. J.; An, Z.; Bai, B.

    2015-03-01

    A method combining proton-induced X-ray emission spectrometry (PIXE) and Rutherford backscattering spectrometry (RBS) was used to determine the composition of 61 porcelain shards from the Yuan Dynasty (1271-1368 A.D.) unearthed from the Waguantan kiln site at Tianzhu County in Guizhou Province, China. Based on our previous experimental setup, an electron gun device with a LaB6 crystal cathode was installed to solve the problem created when the incident proton beams generated electric charge accumulations on the surfaces of the insulating porcelain samples, which induced a large bremsstrahlung background. The use of the electron gun has largely eliminated the large bremsstrahlung background and has therefore improved the detection limits for elements, especially for trace elements, and made it possible to determine the origin of the porcelains based on the trace elements. Major and trace elemental compositions of the porcelain bodies and glazes measured by PIXE and RBS were analyzed by the factor analysis method. The factor analysis showed that a few pieces of porcelain with a style similar to the porcelain of the Longquan kiln among the unearthed porcelains from the Waguantan kiln site did not have obvious differences in elemental compositions from other remaining porcelains unearthed from the Waguantan kiln site, indicating that the pieces of unearthed porcelain with the Longquan kiln style did in fact belong to the product fired locally by imitating the model of the Longquan celadon with local raw materials. This result therefore indicated that the Longquan kiln technology that originated from the Five Dynasties (907-960 A.D.) had been propagated to the Waguantan kiln site of Guizhou Province in the Yuan Dynasty.

  15. Using Apollo Sites and Soils to Compositionally Ground Truth Diviner Lunar Radiometer Observations

    NASA Technical Reports Server (NTRS)

    Greenhagen, Benjamin T.; Lucey, P. G.; Song, E.; Thomas, I R.; Bowles, N. E.; DonaldsonHanna, K. L.; Allen, C.; Foote, E. J.; Paige, D .A.

    2012-01-01

    Apollo landing sites and returned soils afford us a unique opportunity to "ground truth" Diviner Lunar Radiometer compositional observations, which are the first global, high resolution , thermal infrared measurements of an airless body. The Moon is the most accessible member of the most abundant class of solar system objects, which includes Mercury, asteroids, and icy satellites. And the Apollo samples returned from the Moon are the only extraterrestrial samples with known spatial context. Here we compare Diviner observations of Apollo landing sites and compositional and spectral laboratory measurements of returned Apollo soils. Diviner, onboard NASA's Lunar Reconnaissance Orbiter, has three spectral channels near 8 micron that were designed to characterize the mid-infrared emissivity maximum known as the Christiansen feature (CF), a well-studied indicator of silicate mineralogy. It has been observed that thermal infrared spectra measured in simulated lunar environment (SLE) are significantly altered from spectra measured under terrestrial or martian conditions, with enhanced CF contrast and shifted CF position relative to other spectral features. Therefore only thermal emission experiments conducted in SLE are directly comparable to Diviner data. With known compositions, Apollo landing sites and soils are important calibration points for the Diviner dataset, which includes all six Apollo sites at approximately 200 m spatial resolution. Differences in measured CFs caused by composition and space weathering are apparent in Diviner data. Analyses of Diviner observations and SLE measurements for a range of Apollo soils show good agreement, while comparisons to thermal reflectance measurements under ambient conditions do not agree well, which underscores the need for SLE measurements and validates our measurement technique. Diviner observations of Apollo landing sites are also correlated with geochemical measurements of Apollo soils from the Lunar Sample Compendium

  16. Identifying 2'-O-methylationation sites by integrating nucleotide chemical properties and nucleotide compositions.

    PubMed

    Chen, Wei; Feng, Pengmian; Tang, Hua; Ding, Hui; Lin, Hao

    2016-06-01

    2'-O-methylationation is an important post-transcriptional modification and plays important roles in many biological processes. Although experimental technologies have been proposed to detect 2'-O-methylationation sites, they are cost-ineffective. As complements to experimental techniques, computational methods will facilitate the identification of 2'-O-methylationation sites. In the present study, we proposed a support vector machine-based method to identify 2'-O-methylationation sites. In this method, RNA sequences were formulated by nucleotide chemical properties and nucleotide compositions. In the jackknife cross-validation test, the proposed method obtained an accuracy of 95.58% for identifying 2'-O-methylationation sites in the human genome. Moreover, the model was also validated by identifying 2'-O-methylation sites in the Mus musculus and Saccharomyces cerevisiae genomes, and the obtained accuracies are also satisfactory. These results indicate that the proposed method will become a useful tool for the research on 2'-O-methylation. PMID:27191866

  17. Atmospheric dust loads and their elemental composition at a background site in India.

    PubMed

    Negi, B S; Jha, S K; Chavan, S B; Sadasivan, S; Goyal, A; Sapru, M L; Bhat, C L

    2002-01-01

    Air particulate samples collected during 1995-96 at a background site situated on the east coast of Thar Desert in Rajsthan State of India were analysed for atmospheric dust loads (Suspended Particulate Matter) and elemental composition. The values of SPM ranged from 9 microg M(-3) to 97 microg M(-3) with an average of 43 microg M(-3) except a few episodic values, which were 3 to 5 times higher than the average during summer months. The results for elemental composition of the particulate samples showed that the concentrations of anthropogenic toxic trace elements viz. Br, Cr, Pb, Sb, Se and Zn are lower by a factor of 2 to 10 as compared to urban areas. The high enrichment factors for anthropogenic elements viz. Br, Pb, Sb and Zn show an input from coal/wood fuel burning and vehicular pollution at the sampling site. The depletion of Si in SPM samples shows long distance transport of dust to the sampling site. PMID:11878626

  18. Atmospheric aerosol compositions and sources at two national background sites in northern and southern China

    NASA Astrophysics Data System (ADS)

    Zhu, Qiao; He, Ling-Yan; Huang, Xiao-Feng; Cao, Li-Ming; Gong, Zhao-Heng; Wang, Chuan; Zhuang, Xin; Hu, Min

    2016-08-01

    Although China's severe air pollution has become a focus in the field of atmospheric chemistry and the mechanisms of urban air pollution there have been researched extensively, few field sampling campaigns have been conducted at remote background sites in China, where air pollution characteristics on a larger scale are highlighted. In this study, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), together with an Aethalometer, was deployed at two of China's national background sites in northern (Lake Hongze site; 33.23° N, 118.33° E; altitude 21 m) and southern (Mount Wuzhi site; 18.84° N, 109.49° E; altitude 958 m) China in the spring seasons in 2011 and 2015, respectively, in order to characterize submicron aerosol composition and sources. The campaign-average PM1 concentration was 36.8 ± 19.8 µg m-3 at the northern China background (NCB) site, which was far higher than that at the southern China background (SCB) site (10.9 ± 7.8 µg m-3). Organic aerosol (OA) (27.2 %), nitrate (26.7 %), and sulfate (22.0 %) contributed the most to the PM1 mass at NCB, while OA (43.5 %) and sulfate (30.5 %) were the most abundant components of the PM1 mass at SCB, where nitrate only constituted a small fraction (4.7 %) and might have contained a significant amount of organic nitrates (5-11 %). The aerosol size distributions and organic aerosol elemental compositions all indicated very aged aerosol particles at both sites. The OA at SCB was more oxidized with a higher average oxygen to carbon (O / C) ratio (0.98) than that at NCB (0.67). Positive matrix factorization (PMF) analysis was used to classify OA into three components, including a hydrocarbon-like component (HOA, attributed to fossil fuel combustion) and two oxygenated components (OOA1 and OOA2, attributed to secondary organic aerosols from different source areas) at NCB. PMF analysis at SCB identified a semi-volatile oxygenated component (SV-OOA) and a low-volatility oxygenated

  19. Walker Branch Throughfall Displacement Experiment Data Report: Site Characterization, System Performance, Weather, Species Composition, and Growth

    SciTech Connect

    Hanson, P.J.

    2001-09-04

    This numeric data package provides data sets, and accompanying documentation, on site characterization, system performance, weather, species composition, and growth for the Throughfall Displacement Experiment, which was established in the Walker Branch Watershed of East Tennessee to provide data on the responses of forests to altered precipitation regimes. The specific data sets include soil water content and potential, coarse fraction of the soil profile, litter layer temperature, soil temperature, monthly weather, daily weather, hourly weather, species composition of trees and saplings, mature tree and sapling annual growth, and relative leaf area index. Fortran and SAS{trademark} access codes are provided to read the ASCII data files. The data files and this documentation are available without charge on a variety of media and via the Internet from the Carbon Dioxide Information Analysis Center (CDIAC).

  20. Metals other than uranium affected microbial community composition in a historical uranium-mining site.

    PubMed

    Sitte, Jana; Löffler, Sylvia; Burkhardt, Eva-Maria; Goldfarb, Katherine C; Büchel, Georg; Hazen, Terry C; Küsel, Kirsten

    2015-12-01

    To understand the links between the long-term impact of uranium and other metals on microbial community composition, ground- and surface water-influenced soils varying greatly in uranium and metal concentrations were investigated at the former uranium-mining district in Ronneburg, Germany. A soil-based 16S PhyloChip approach revealed 2358 bacterial and 35 archaeal operational taxonomic units (OTU) within diverse phylogenetic groups with higher OTU numbers than at other uranium-contaminated sites, e.g., at Oak Ridge. Iron- and sulfate-reducing bacteria (FeRB and SRB), which have the potential to attenuate uranium and other metals by the enzymatic and/or abiotic reduction of metal ions, were found at all sites. Although soil concentrations of solid-phase uranium were high, ranging from 5 to 1569 μg·g (dry weight) soil(-1), redundancy analysis (RDA) and forward selection indicated that neither total nor bio-available uranium concentrations contributed significantly to the observed OTU distribution. Instead, microbial community composition appeared to be influenced more by redox potential. Bacterial communities were also influenced by bio-available manganese and total cobalt and cadmium concentrations. Bio-available cadmium impacted FeRB distribution while bio-available manganese and copper as well as solid-phase zinc concentrations in the soil affected SRB composition. Archaeal communities were influenced by the bio-available lead as well as total zinc and cobalt concentrations. These results suggest that (i) microbial richness was not impacted by heavy metals and radionuclides and that (ii) redox potential and secondary metal contaminants had the strongest effect on microbial community composition, as opposed to uranium, the primary source of contamination. PMID:26122566

  1. Assessment of fish abundance and species composition at selected sites in South Dakota: an overview

    USGS Publications Warehouse

    Harwood, Alison

    2010-01-01

    The U.S. Geological Survey (USGS) conducted surveys of streams throughout the State of South Dakota during 2008-09 as part of the U.S. Environmental Protection Agency?s (USEPA) National Rivers and Streams Assessment (NRSA) Program. During 2008-09, as part of the stream assessment, the USGS completed surveys of fish populations and species composition at 64 sites. Fish were inventoried at 60 of the 64 sites, but not at four of the sites because water was too low to sustain fish or specific conductivity was too high to electroshock effectively. Four of the sites were surveyed in 2000-04 during the USEPA's Environmental Monitoring and Assessment Program-West (EMAP-West) project. Two wadeable sites and two boatable sites were revisited for quality-assurance/quality-control requirements. During the study, both wadeable and boatable streams were sampled using electrofishing equipment and methods. Of the 64 sites, 62 were wadeable and 2 were boatable. Procedures for sampling wadeable streams differed slightly from procedures for boatable streams. Backpack electrofishing equipment was used for wadeable streams, whereas boat electrofishing equipment was used for boatable streams. Wadeable streams also were fished in an opposite direction than boatable streams. Several species of fish were collected during the NRSA. Species diversity ranged from 0-11 species in wadeable streams and from 6-26 species in boatable streams. Many common species were sampled during the study. The most frequently sampled fish was the sand shiner (Notropis stramineus), with 609 individuals sampled. In contrast, only one heritage species, the skipjack herring (Alosa chrysochloris), was identified during 2008-09. Common anomalies found in fish caught were parasitic lesions, "black spot disease," and tumors. When comparing the fish sampling results for the four sites visited in both 2000-04 and in 2008-09, more individuals and species were collected during 2008-09 than in 2000-04 at two sites, whereas

  2. Composition and temperature dependences of site occupation for Al, Cr, W, and Nb in MoSi2

    NASA Astrophysics Data System (ADS)

    Li, Xiao-Ping; Sun, Shun-Ping; Yu, Yun; Wang, Hong-Jin; Jiang, Yong; Yi, Dan-Qing

    2015-12-01

    The composition and temperature dependences of site occupation for Al, Cr, W, and Nb in MoSi2 are investigated by using a thermodynamics model and first principles calculations. A simple parameter measuring the substitution energy difference between Si and Mo sites reflects the nature of site occupancy. At 0 K, these elements prefer Si sites in Mo-rich and Mo sites in Si-rich, and show no site preference in stoichiometric MoSi2. At elevated temperature, the site occupation behaviors show strong dependence on both composition and temperature. Some calculated results have been certified in previous experiments. Project supported by the National Natural Science Foundation of China (Grant No. 51401093) and the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20130233).

  3. Why Doesn't The GRE or GPA Work in Selecting Graduate Students & What Alternatives Are There ?

    NASA Astrophysics Data System (ADS)

    Sedlacek, William

    2014-01-01

    The simplest response to the title of this paper is that the measures that are commonly employed in evaluating prospective graduate and professional students don’t work. That is, scores from the Graduate Record Examination (GRE) and prior grades (GPA) appear to have little validity in assessing postbaccalaureate student potential (Sternberg & Williams, 1997; Sedlacek, 1998, 2004; Bair & Haworth, 1999). Measurement problems such as restriction of range will discussed and the need to consider a multiverse statistical model presented. An alternative assessment system based on noncognitive variables will be presented and examples of its use with graduate and professional students discussed (Sedlacek, 2004, 2012, in press).

  4. New Composite Membranes for High Throughput Solid-Liquid Separations at the Savannah River Site

    SciTech Connect

    Bhave, Ramesh R

    2012-01-01

    New Composite Membranes for High Throughput Solid-Liquid Separations at the Savannah River Site R. Bhave (Oak Ridge National Laboratory. Oak Ridge, TN) and M. R. Poirier* (Savannah River National Laboratory, Aiken SC) Solid-liquid separation is the limiting step for many waste treatment processes at the Savannah River Site. SRNL researchers have identified the rotary microfilter as a technology to improve the rate of solid-liquid separation processes. SRNL is currently developing the rotary microfilter for radioactive service and plans to deploy the technology as part of the small column ion exchange process. The rotary microfilter can utilize any filter media that is available as a flat sheet. The current baseline membrane is a 0.5 micron (nominal) porous metal filter (Pall PMM050). Previous testing with tubular filters showed that filters composed of a ceramic membrane on top of a stainless steel support produce higher flux than filters composed only of porous metal. The authors are working to develop flat sheet filter media composed of a ceramic membrane and/or ceramic-metal composite on top of a porous stainless steel support that can be used with the rotary microfilter to substantially increase filter flux resulting in a more compact, energy efficient and cost-effective high level radioactive waste treatment system. Composite membranes with precisely controlled pore size distribution were fabricated on porous metal supports. High quality uniform porous metal (316SS) supports were fabricated to achieve high water permeability. Separative layers of several different materials such as ultrafine metal particles and ceramic oxides were used to fabricate composite membranes. The fabrication process involved several high temperature heat treatments followed by characterization of gas and liquid permeability measurements and membrane integrity analysis. The fabricated composite membrane samples were evaluated in a static test cell manufactured by SpinTek. The

  5. A framework to spatially cluster air pollution monitoring sites in US based on the PM2.5 composition

    PubMed Central

    Austin, Elena; Coull, Brent A.; Zanobetti, Antonella; Koutrakis, Petros

    2013-01-01

    Background Heterogeneity in the response to PM2.5 is hypothesized to be related to differences in particle composition across monitoring sites which reflect differences in source types as well as climatic and topographic conditions impacting different geographic locations. Identifying spatial patterns in particle composition is a multivariate problem that requires novel methodologies. Objectives Use cluster analysis methods to identify spatial patterns in PM2.5 composition. Verify that the resulting clusters are distinct and informative. Methods 109 monitoring sites with 75% reported speciation data during the period 2003–2008 were selected. These sites were categorized based on their average PM2.5 composition over the study period using k-means cluster analysis. The obtained clusters were validated and characterized based on their physico-chemical characteristics, geographic locations, emissions profiles, population density and proximity to major emission sources. Results Overall 31 clusters were identified. These include 21 clusters with 2 or more sites which were further grouped into 4 main types using hierarchical clustering. The resulting groupings are chemically meaningful and represent broad differences in emissions. The remaining clusters, encompassing single sites, were characterized based on their particle composition and geographic location. Conclusions The framework presented here provides a novel tool which can be used to identify and further classify sites based on their PM2.5 composition. The solution presented is fairly robust and yielded groupings that were meaningful in the context of air-pollution research. PMID:23850585

  6. Addendum to Composite Analysis for Low-Level Waste Disposal in the 200 Area Plateau of the Hanford Site

    SciTech Connect

    Bergeron, Marcel P.; Freeman, Eugene J.; Wurstner, Signe K.; Kincaid, Charles T.; Coony, Mike M.; Strenge, Dennis L.; Aaberg, Rosanne L.; Eslinger, Paul W.

    2001-09-28

    This report summarizes efforts to complete an addendum analysis to the first iteration of the Composite Analysis for Low-Level Waste Disposal in the 200 Area Plateau of the Hanford Site (Composite Analysis). This document describes the background and performance objectives of the Composite Analysis and this addendum analysis. The methods used, results, and conclusions for this Addendum analysis are summarized, and recommendations are made for work to be undertaken in anticipation of a second analysis.

  7. Unsaturated zone carbon dioxide flux, mixing, and isotopic composition at the USGS Amargosa Desert Research Site

    NASA Astrophysics Data System (ADS)

    Conaway, C. H.; Thordsen, J. J.; Thomas, B.; Haase, K.; Moreo, M. T.; Walvoord, M. A.; Andraski, B. J.; Stonestrom, D. A.

    2015-12-01

    Elevated concentrations of tritium, radiocarbon, and volatile organic compounds at the USGS Amargosa Desert Research Site, adjacent to a low-level radioactive waste disposal facility, have stimulated research on factors affecting transport of these contaminants. This research includes an examination of unsaturated zone carbon dioxide (CO2) fluxes, mixing, and isotopic composition, which can help in understanding these factors. In late April 2015 we collected 76 soil-gas samples in multi-layer foil bags from existing 1.5-m deep tubes, both inside and outside the low-level waste area, as well as from two 110-m-deep multilevel gas-sampling boreholes and a distant background site. These samples were analyzed for carbon dioxide concentration and isotopic composition by direct injection into a cavity ring-down spectrometer. Graphical analysis of results indicates mixing of CO2 characteristic of the root zone (δ13C -18 ‰ VPDB), deep soil gas of the capillary fringe (-20‰), and CO2 produced by microbial respiration of organic matter disposed in the waste area trenches (-28‰). Land-surface boundary conditions are being constrained by the application of a novel non-dispersive infrared sensor and traditional concentration and flux measurements, including discrete CO2 flux data using a gas chamber method to complement continuous data from surface- and tower-based CO2 sensors. These results shed light on radionuclide and VOC mobilization and transport mechanisms from this and similar waste disposal facilities.

  8. Influence of cultivation site on sesquiterpene lactone composition of forage chicory (Cichorium intybus L.).

    PubMed

    Foster, Joyce G; Clapham, William M; Belesky, David P; Labreveux, Maria; Hall, Marvin H; Sanderson, Matt A

    2006-03-01

    The forage potential of chicory (Cichorium intybus L.) has not been realized in southern West Virginia (WV) because ruminants are reluctant to consume the herbage. Chicory contains bitter sesquiterpene lactones that can adversely impact palatability. This study was undertaken to determine whether sesquiterpene lactone concentrations in chicory grown in southern WV differ from those in chicory grown in central Pennsylvania (PA) where chicory is grazed readily. Herbage was collected in 1997 and 1998 from cultivars Grasslands Puna (Puna), INIA le Lacerta (Lacerta), and Forage Feast established at research sites near State College, PA, and Beckley, WV. The total concentration of sesquiterpene lactones in WV-grown cultivars was 0.58% (dry matter basis) in Puna, 0.59% in Lacerta, and 0.79% in Forage Feast in 1997 and ranged from 1.03 (Lacerta) to 1.52% (Forage Feast) in 1998. In PA-grown cultivars, sesquiterpene lactones represented 0.16 (Puna), 0.18 (Lacerta), and 0.27% (Forage Feast) of the forage dry matter in 1997 and ranged from 0.32 (Lacerta) to 0.55% (Forage Feast) in 1998. Concentrations of lactucin, lactucopicrin, and total sesquiterpene lactones in Forage Feast exceeded those in the other cultivars grown at the same site. The lowest concentrations of lactucopicrin and total sesquiterpene lactones observed among WV-grown cultivars were higher (2-fold or more) than the highest concentrations present in cultivars grown the same year in PA. Mineral analyses of soils from the two cultivation sites indicate that P availability may influence sesquiterpene lactone composition of chicory herbage. Results provide a foundation for future studies of environmental effects on sesquiterpene lactone composition and palatability of chicory herbage. PMID:16506832

  9. Evaluation of distance maps from fast GRE MRI as a tool to study the knee joint space

    NASA Astrophysics Data System (ADS)

    Tamez-Pena, Jose G.; Lerner, Amy L.; Yao, Jiang; Salo, Arthur D.; Totterman, Saara

    2003-05-01

    A new three-dimensional (3D) method of evaluating the joint space from fast GRE MRI has been developed that allows the reconstruction of the two dimensional (2D) distance map between the femur and the tibia bone plates. This method uses the MRI data, an automated 3D segmentation, and an unsupervised joint space extraction algorithm that identify the medial and lateral compartments of the knee joint. The extracted medial and lateral compartments of the tibia-femur joint space were analyzed by 2D distance maps, where visual as well quantitative information was extracted. This method was applied to study the dynamic behavior of the knee joint space under axial load. Three healthy volunteers' knees were imaged using fast GRE sequences in a clinical scanner under unloaded (normal) conditions and with an axial load that mimics the person's standing load. Furthermore, one volunteer's knee was imaged at four regular time intervals while the load was applied and at four regular intervals without load. The results show that changes of 50 microns in the average distance between bones can be measured and that normal axial loads reduce the joint space width significantly and can be detected by this method.

  10. [Chemical composition analysis of early neolithic pottery unearthed from Xiaohuangshang site, Zhejiang Province and Jiahu site, Henan Province by energy disperse X-ray fluorescence].

    PubMed

    Chen, Qian-Qian; Yang, Yu-Zhang; Zhang, Ju-Zhong; Cui, Wei

    2011-11-01

    The major elements in the early neolithic potteries unearthed from Xiaohuangshan site, Zhejiang Province and Jiahu site, Henan Province were determined by energy disperse X-ray fluorescence (EDXRF). The results show that the chemical compositions of the potteries from these two sites possess obvious regional features respectively. Compared with the specimen from Jiahu site, the potteries from Xiaohuangshan site have the common feature of ancient Chinese southern ceramics with high silicon and low aluminum contents. Simultaneously, the chemical composition of Xiaohuangshan pottery samples nearly unchanged from its early stage to the last stage. This phenomenon indicates that the source of the ceramic raw materials of Xiaohuangshan site was stable, and the continuous improvement of its pottery quality was mainly due to the progress in sintering techniques. However, the chemical composition of Jiahu potteries changed a lot in its three different periods. This change occurred because a large number of admixtures were added to the pottery bodies to improve their operating performances. These results also show that the improvements of pottery making techniques in different Chinese areas may have their own evolution directions respectively for the different geographical environments. PMID:22242535

  11. HANFORD SITE LOW EXPOSURE PIPELINE REPAIR USING A NON-METALLIC COMPOSITE SYSTEM

    SciTech Connect

    HUTH RJ

    2009-11-12

    At the Department of Energy, Richland Operations (DOE-RL) Hanford site in eastern Washington, a 350 mm (14 inch) diameter high density polyethylene (HDPE) pump recirculation pipeline failed at a bonded joint adjacent to a radiologically and chemically contaminated groundwater storage basin. The responsible DOE-RL contractor, CH2MHill Plateau Remediation Company, applied a fiberglass reinforced plastic (composite) field repair system to the failed joint. The system was devised specifically for the HDPE pipe repair at the Hanford site, and had not been used on this type of plastic piping previously. This paper introduces the pipe failure scenario, describes the options considered for repair and discusses the ultimate resolution of the problem. The failed pipeline was successfully returned to service with minimal impact on waste water treatment plant operating capacity. Additionally, radiological and chemical exposures to facility personnel were maintained as low as reasonably achievable (ALARA). The repair is considered a success for the near term, and future monitoring will prove whether the repair can be considered for long term service and as a viable alternative for similar piping failures at the Hanford site.

  12. Ionic composition of rainwater at selected sites of Kuantan, Pahang, Malaysia: a preliminary study.

    PubMed

    Tay, Joo Hui; Jaafar, Syakhsiah; Mohd Tahir, Norhayati

    2014-03-01

    A short-term investigation on the chemical composition of rainwater was carried out at five selected sampling stations in Kuantan district, Pahang, Malaysia. Sampling of rainwater was conducted by event basis between September and November 2011. Rainwater samples were collected using polyethylene containers and the parameters measured were cations (sodium, potassium, ammonium, calcium and magnesium) and anions (chlorides, nitrates and sulphates). The average pH value for rainwater samples was 6.0 ± 0.57 in which most of the sampling sites exhibited pH values >5.6. Calcium and sulphate were the most abundant cation and anion, respectively, whilst the concentrations of other major ions varied according to sampling location. PMID:24435136

  13. Culicoides species composition and environmental factors influencing African horse sickness distribution at three sites in Namibia.

    PubMed

    Liebenberg, Danica; Piketh, Stuart; Labuschagne, Karien; Venter, Gert; Greyling, Telane; Mienie, Charlotte; de Waal, Tania; van Hamburg, Huib

    2016-11-01

    African horse sickness (AHS) is one of the most lethal infectious, non-contagious, vector-borne disease of equids. The causative agent, African horse sickness virus (AHSV) is transmitted via Culicoides midges (Diptera: Ceratopogonidae). AHS is endemic to Namibia but detailed studies of Culicoides communities and influencing environmental parameters are limited. This study aims to determine the Culicoides species composition at three different sites and to assess environmental parameters influencing the geographical distribution of AHS in Namibia. Weekly collections of Culicoides were made during the AHS peak season from January to May for 2013 and 2014 using the Onderstepoort 220V UV-light trap. Out of 397 collections made, 124 collections (3287 Culicoides) were analysed for AHSV presence with RT-qPCR. A total of 295 collections were analysed for total Culicoides (all collected Culicoides individuals) and in 75% of these collections the Culicoides were identified to species level. C. imicola was the dominant species with proportional representation of 29.9%. C. subschultzei, C. exspectator and C. ravus each contribute more than 10% to the species composition. The lowest number of Culicoides was collected at Aus 9980, a total of 21819 at Windhoek and the highest number at Okahandja 47343. AHSV was present at all three sites during 2013 but only in Windhoek and Okahandja during 2014. Multivariate analyses of data from the two year survey indicate the environmental parameters in order of importance for the distribution of AHS in Namibia as precipitation>temperature>clay>relative humidity>NDVI. The implication of these findings is that any precipitation event increases Culicoides numbers significantly. Together with these results the high number of species found of which little is known regarding their vector competence, add to the complexity of the distribution of AHS in Namibia. PMID:27491343

  14. Factors, origin and sources affecting PM1 concentrations and composition at an urban background site

    NASA Astrophysics Data System (ADS)

    Squizzato, Stefania; Masiol, Mauro; Agostini, Chiara; Visin, Flavia; Formenton, Gianni; Harrison, Roy M.; Rampazzo, Giancarlo

    2016-11-01

    PM1 is widely believed to provide better information on the anthropogenic fraction of particulate matter pollution than PM2.5. However, data on PM1 are still limited in Europe as well as comprehensive information about its chemical composition and source apportionment and this gap is more evident in the pollution hot-spots still remaining in Europe, such as the Po Valley (Northern Italy). Elemental and organic carbon, 7 water soluble inorganic ions and 17 elements were quantified in 117 PM1 samples collected at an urban background site in Venice-Mestre, a large city located in the eastern Po Valley, during winter (December 2013-February 2014) and summer (May-July 2014) periods. Results show a strong seasonality for PM1 mass concentration (averages ranging from 6 ± 2 in summer to 34 ± 24 μg m- 3 in winter) and for most of the analysed species. Components mainly related to road traffic, residential heating, biomass burning and secondary inorganic aerosol (ammonium nitrate) reached their highest levels in winter, while mineral dust and marine components were elevated in summer. PMF analysis revealed 7 potential sources. Secondary inorganic aerosol (33%) and biomass burning (33%) are the major contributor in winter followed by EC-primary emissions (16%), aged sulphate (6%), road traffic (7%), fossil fuel combustion (%) and marine aerosol (3%). During summer, these sources account for 12%, 14%, 20%, 22%, 8%, 14% and 10%, respectively. Some PM1 sources are located near the sampling site (residential area, traffic road, industrial area) but a major contribution of long range transport is observed when high pollution events occur. The results give useful insights into PM1 composition in an urban area and chemical profiles of sources helpful in the interpretation of receptor model results.

  15. Motif types, motif locations and base composition patterns around the RNA polyadenylation site in microorganisms, plants and animals

    PubMed Central

    2014-01-01

    Background The polyadenylation of RNA is critical for gene functioning, but the conserved sequence motifs (often called signal or signature motifs), motif locations and abundances, and base composition patterns around mRNA polyadenylation [poly(A)] sites are still uncharacterized in most species. The evolutionary tendency for poly(A) site selection is still largely unknown. Results We analyzed the poly(A) site regions of 31 species or phyla. Different groups of species showed different poly(A) signal motifs: UUACUU at the poly(A) site in the parasite Trypanosoma cruzi; UGUAAC (approximately 13 bases upstream of the site) in the alga Chlamydomonas reinhardtii; UGUUUG (or UGUUUGUU) at mainly the fourth base downstream of the poly(A) site in the parasite Blastocystis hominis; and AAUAAA at approximately 16 bases and approximately 19 bases upstream of the poly(A) site in animals and plants, respectively. Polyadenylation signal motifs are usually several hundred times more abundant around poly(A) sites than in whole genomes. These predominant motifs usually had very specific locations, whether upstream of, at, or downstream of poly(A) sites, depending on the species or phylum. The poly(A) site was usually an adenosine (A) in all analyzed species except for B. hominis, and there was weak A predominance in C. reinhardtii. Fungi, animals, plants, and the protist Phytophthora infestans shared a general base abundance pattern (or base composition pattern) of “U-rich—A-rich—U-rich—Poly(A) site—U-rich regions”, or U-A-U-A-U for short, with some variation for each kingdom or subkingdom. Conclusion This study identified the poly(A) signal motifs, motif locations, and base composition patterns around mRNA poly(A) sites in protists, fungi, plants, and animals and provided insight into poly(A) site evolution. PMID:25052519

  16. Impact of wildfires on size-resolved aerosol composition at a coastal California site

    NASA Astrophysics Data System (ADS)

    Maudlin, L. C.; Wang, Z.; Jonsson, H. H.; Sorooshian, A.

    2015-10-01

    Size-resolved aerosol composition measurements were conducted at a coastal site in central California during the Nucleation in California Experiment (NiCE) between July and August of 2013. The site is just east of ship and marine emission sources and is also influenced by continental pollution and wildfires, such as those near the California-Oregon border which occurred near the end of NiCE. Two micro-orifice uniform deposit impactors (MOUDIs) were used, and water-soluble and elemental compositions were measured. The five most abundant water-soluble species (in decreasing order) were chloride, sodium, non-sea salt (nss) sulfate, ammonium, and nitrate. During wildfire periods, nss K mass concentrations were not enhanced as strongly as other species in the sub-micrometer stages and even decreased in the super-micrometer stages; species other than nss K are more reliable tracers for biomass burning in this region. Chloride levels were reduced in the fire sets likely due to chloride depletion by inorganic and organic acids that exhibited elevated levels in transported plumes. During wildfire periods, the mass size distribution of most dicarboxylic acids changed from unimodal to bimodal with peaks in the 0.32 μm and 1.0-1.8 μm stages. Furthermore, sulfate's peak concentration shifted from the 0.32 μm to 0.56 μm stage, and nitrate also shifted to larger sizes (1.0 μm to 1.8-3.2 μm stages). Mass concentrations of numerous soil tracer species (e.g., Si, Fe) were strongly enhanced in samples influenced by wildfires, especially in the sub-micrometer range. Airborne cloud water data confirm that soil species were associated with fire plumes transported south along the coast. In the absence of biomass burning, cloud condensation nuclei (CCN) composition is dominated by nss sulfate and ammonium, and the water-soluble organic fraction is dominated by methanesulfonate, whereas for the samples influenced by wildfires, ammonium becomes the dominant overall species, and

  17. Bacterial community composition of chronic periodontitis and novel oral sampling sites for detecting disease indicators

    PubMed Central

    2014-01-01

    Background Periodontitis is an infectious and inflammatory disease of polymicrobial etiology that can lead to the destruction of bones and tissues that support the teeth. The management of chronic periodontitis (CP) relies heavily on elimination or at least control of known pathogenic consortia associated with the disease. Until now, microbial plaque obtained from the subgingival (SubG) sites has been the primary focus for bacterial community analysis using deep sequencing. In addition to the use of SubG plaque, here, we investigated whether plaque obtained from supragingival (SupG) and tongue dorsum sites can serve as alternatives for monitoring CP-associated bacterial biomarkers. Results Using SubG, SupG, and tongue plaque DNA from 11 healthy and 13 diseased subjects, we sequenced V3 regions (approximately 200 bases) of the 16S rRNA gene using Illumina sequencing. After quality filtering, approximately 4.1 million sequences were collapsed into operational taxonomic units (OTUs; sequence identity cutoff of >97%) that were classified to a total of 19 phyla spanning 114 genera. Bacterial community diversity and overall composition was not affected by health or disease, and multiresponse permutation procedure (MRPP) on Bray-Curtis distance measures only supported weakly distinct bacterial communities in SubG and tongue plaque depending on health or disease status (P < 0.05). Nonetheless, in SubG and tongue sites, the relative abundance of Firmicutes was increased significantly from health to disease and members of Synergistetes were found in higher abundance across all sites in disease. Taxa indicative of CP were identified in all three locations (for example, Treponema denticola, Porphyromonas gingivalis, Synergistes oral taxa 362 and 363). Conclusions For the first time, this study demonstrates that SupG and tongue dorsum plaque can serve as alternative sources for detecting and enumerating known and novel bacterial biomarkers of CP. This finding is clinically

  18. Machine-Scorable Complex Constructed-Response Quantitative Items: Agreement between Expert System and Human Raters' Scores. GRE Board Professional Report No. 88-07aP.

    ERIC Educational Resources Information Center

    Sebrechts, Marc M.; And Others

    This study evaluated agreement between expert system and human scores on 12 algebra word problems taken by Graduate Record Examinations (GRE) General Test examinees from a general sample of 285 and a study sample of 30. Problems were drawn from three content classes (rate x time, work, and interest) and presented in four constructed-response…

  19. Development and Evaluation of Computer-Administered Analytical Questions for the Graduate Record Examinations General Test. GRE Board Professional Report No. 88-06P.

    ERIC Educational Resources Information Center

    Bridgeman, Brent; Rock, Donald A.

    Three new computer-administered item types for the analytical scale of the Graduate Record Examination (GRE) General Test were developed and evaluated. One item type was a free-response version of the current analytical reasoning item type. The second item type was a somewhat constrained free-response version of the pattern identification (or…

  20. Test Anxiety and Test Performance: Comparing Paper-based and Computer-Adaptive Versions of the Graduate Record Examinations (GRE) General Test.

    ERIC Educational Resources Information Center

    Powers, Donald E.

    2001-01-01

    Tests the hypothesis that the introduction of computer-adaptive testing may help to alleviate test anxiety and diminish the relationship between test anxiety and test performance. Compares a sample of Graduate Record Examinations (GRE) General Test takers who took the computer-adaptive version of the test with another sample who took the…

  1. The Relationship between GRE Scores and Performance on the Standard Principal Examination for Certification of Educators in Texas (ExCET).

    ERIC Educational Resources Information Center

    Jones, Timothy B.; Sherman, Ross B.; Ninness, H. A.; Hallman, Patsy J.

    Graduate programs in Educational Administration use a variety of screening strategies, including the Graduate Records Examination (GRE) when selecting and admitting students. In order to earn Standard Principal Certification in Texas, an Educational Administration candidate, in addition to completing a graduate program, must also pass the Standard…

  2. How Well Does the GRE Work for Your University? An Empirical Institutional Case Study of the Graduate Record Examination across Multiple Disciplines.

    ERIC Educational Resources Information Center

    Rubio, Doris McGartland; Rubin, Robert S.; Brennan, Donald G.

    2003-01-01

    This case study was designed to demonstrate how an institution could use readily available archival data to produce a simple yet informative validity study as a necessary step in understanding the effectiveness of their selection process. Results indicated the GRE does not significantly predict graduate school success across all disciplines…

  3. The Predictive Validity of the GRE and TOEFL Exams with GGPA as the Criterion of Graduate Success for International Graduate Students in Science and Engineering.

    ERIC Educational Resources Information Center

    Neal, Menka E.

    This study investigated the relationship between graduate grade-point-average (GGPA) and the total score, as well as the scores on each part, of the Graduate Record Examination (GRE). It also investigated the relationship between GGPA and the total score, as well as the scores on each part, of the Test of English as a Foreign Language (TOEFL). The…

  4. The GRE Subject Test Performance of U.S. and Non-U.S. Examinees, 1982-84: A Comparative Analysis.

    ERIC Educational Resources Information Center

    Wilson, Kenneth M.

    The Graduate Record Examination (GRE) subject-matter achievement tests are offered in 17 fields. This study investigated the performance of U.S. and non-U.S. citizens on the Subject Tests, and the relationship of selected English-proficiency-related background variables to the test performance of non-U.S. citizens. It was also concerned with…

  5. MO-G-17A-03: MR-Based Cortical Bone Segmentation for PET Attenuation Correction with a Non-UTE 3D Fast GRE Sequence

    SciTech Connect

    Ai, H; Pan, T; Hwang, K

    2014-06-15

    Purpose: To determine the feasibility of identifying cortical bone on MR images with a short-TE 3D fast-GRE sequence for attenuation correction of PET data in PET/MR. Methods: A water-fat-bone phantom was constructed with two pieces of beef shank. MR scans were performed on a 3T MR scanner (GE Discovery™ MR750). A 3D GRE sequence was first employed to measure the level of residual signal in cortical bone (TE{sub 1}/TE{sub 2}/TE{sub 3}=2.2/4.4/6.6ms, TR=20ms, flip angle=25°). For cortical bone segmentation, a 3D fast-GRE sequence (TE/TR=0.7/1.9ms, acquisition voxel size=2.5×2.5×3mm{sup 3}) was implemented along with a 3D Dixon sequence (TE{sub 1}/TE{sub 2}/TR=1.2/2.3/4.0ms, acquisition voxel size=1.25×1.25×3mm{sup 3}) for water/fat imaging. Flip angle (10°), acquisition bandwidth (250kHz), FOV (480×480×144mm{sup 3}) and reconstructed voxel size (0.94×0.94×1.5mm{sup 3}) were kept the same for both sequences. Soft tissue and fat tissue were first segmented on the reconstructed water/fat image. A tissue mask was created by combining the segmented water/fat masks, which was then applied on the fast-GRE image (MRFGRE). A second mask was created to remove the Gibbs artifacts present in regions in close vicinity to the phantom. MRFGRE data was smoothed with a 3D anisotropic diffusion filter for noise reduction, after which cortical bone and air was separated using a threshold determined from the histogram. Results: There is signal in the cortical bone region in the 3D GRE images, indicating the possibility of separating cortical bone and air based on signal intensity from short-TE MR image. The acquisition time for the 3D fast-GRE sequence was 17s, which can be reduced to less than 10s with parallel imaging. The attenuation image created from water-fat-bone segmentation is visually similar compared to reference CT. Conclusion: Cortical bone and air can be separated based on intensity in MR image with a short-TE 3D fast-GRE sequence. Further research is required

  6. Non-rigid registration and KLT filter to improve SNR and CNR in GRE-EPI myocardial perfusion imaging.

    PubMed

    Mihai, Georgeta; Ding, Yu; Xue, Hui; Chung, Yiu-Cho; Rajagopalan, Sanjay; Guehring, Jens; Simonetti, Orlando P

    2012-12-01

    The purpose of the study was to evaluate the effect of motion compensation by non-rigid registration combined with the Karhunen-Loeve Transform (KLT) filter on the signal to noise (SNR) and contrast-to-noise ratio (CNR) of hybrid gradient-echo echoplanar (GRE-EPI) first-pass myocardial perfusion imaging. Twenty one consecutive first-pass adenosine stress perfusion MR data sets interpreted positive for ischemia or infarction were processed by non-rigid Registration followed by KLT filtering. SNR and CNR were measured in abnormal and normal myocardium in unfiltered and KLT filtered images following non-rigid registration to compensate for respiratory and other motions. Image artifacts introduced by filtering in registered and nonregistered images were evaluated by two observers. There was a statistically significant increase in both SNR and CNR between normal and abnormal myocardium with KLT filtering (mean SNR increased by 62.18% ± 21.05% and mean CNR increased by 58.84% ± 18.06%; p = 0.01). Motion correction prior to KLT filtering reduced significantly the occurrence of filter induced artifacts (KLT only-artifacts in 42 out of 55 image series vs. registered plus KLT-artifacts in 3 out of 55 image series). In conclusion the combination of non- rigid registration and KLT filtering was shown to increase the SNR and CNR of GRE-EPI perfusion images. Subjective evaluation of image artifacts revealed that prior motion compensation significantly reduced the artifacts introduced by the KLT filtering process. PMID:23936584

  7. Adaptive robust motion trajectory tracking control of pneumatic cylinders with LuGre model-based friction compensation

    NASA Astrophysics Data System (ADS)

    Meng, Deyuan; Tao, Guoliang; Liu, Hao; Zhu, Xiaocong

    2014-07-01

    Friction compensation is particularly important for motion trajectory tracking control of pneumatic cylinders at low speed movement. However, most of the existing model-based friction compensation schemes use simple classical models, which are not enough to address applications with high-accuracy position requirements. Furthermore, the friction force in the cylinder is time-varying, and there exist rather severe unmodelled dynamics and unknown disturbances in the pneumatic system. To deal with these problems effectively, an adaptive robust controller with LuGre model-based dynamic friction compensation is constructed. The proposed controller employs on-line recursive least squares estimation (RLSE) to reduce the extent of parametric uncertainties, and utilizes the sliding mode control method to attenuate the effects of parameter estimation errors, unmodelled dynamics and disturbances. In addition, in order to realize LuGre model-based friction compensation, the modified dual-observer structure for estimating immeasurable friction internal state is developed. Therefore, a prescribed motion tracking transient performance and final tracking accuracy can be guaranteed. Since the system model uncertainties are unmatched, the recursive backstepping design technology is applied. In order to solve the conflicts between the sliding mode control design and the adaptive control design, the projection mapping is used to condition the RLSE algorithm so that the parameter estimates are kept within a known bounded convex set. Finally, the proposed controller is tested for tracking sinusoidal trajectories and smooth square trajectory under different loads and sudden disturbance. The testing results demonstrate that the achievable performance of the proposed controller is excellent and is much better than most other studies in literature. Especially when a 0.5 Hz sinusoidal trajectory is tracked, the maximum tracking error is 0.96 mm and the average tracking error is 0.45 mm. This

  8. Fine mode aerosol composition at three long-term atmospheric monitoring sites in the Amazon Basin

    SciTech Connect

    Artaxo, P.; Gerab, F.; Yamasoe, M.A.; Martins, J.V.

    1994-11-01

    The Amazon Basin tropical rain forest is a key region to study processes that are changing the composition of the global atmosphere, including the large amount of fine mode aerosol particles emitted during biomass burning that might influence the global atmosphere. Three background monitoring stations, Alta Floresta, Cuiaba, and Serra do Navio, are operating continuously measuring aerosol composition. Fine (particle diameter less than 2.0 microns) and coarse (particle diameter greater than 2.0 microns and less than 10 microns) mode aerosol particles were collected using stacked filter units. Particle-induced X-ray emission was used to measure concentrations of up to 20 elements in the fine mode: Al, Si, P, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Rb, Sr, Zr, and Pb. Soot carbon and gravimetric mass analysis were also performed. Absolute Principal Factor Analysis (APFA) has derived absolute elemental source profiles. APFA showed four aerosol particle components: soil dust (Al, Ca, Ti, Mn, Fe), biomass burning (soot, fine mode mass concentration, K, Cl), natural primary biogenic particles with gas-to-particle component (K, S, Ca, Mn, Zn), and marine aerosol (Cl). Biogenic and biomass burning aerosol particles dominate the fine mode mass concentration, with the presence of K, P, S, Cl, Zn, Br, and fine mode mass concentration (FPM). At the Alta Floresta and Cuiaba sites, during the dry season, a strong component of biomass burning is observed. Inhalable particulate matter (particle diameter less than 10 microns) mass concentration up to 700 micrograms/cu m was measured. Fine particle mass concentration alone can go as high as 400 micrograms/cu m for large regions.

  9. Organic aerosol molecular composition and gas-particle partitioning coefficients at a Mediterranean site (Corsica).

    PubMed

    Rossignol, Stéphanie; Couvidat, Florian; Rio, Caroline; Fable, Sébastien; Grignion, Guillaume; Savelli; Pailly, Olivier; Leoz-Garziandia, Eva; Doussin, Jean-Francois; Chiappini, Laura

    2016-02-01

    Molecular speciation of atmospheric organic matter was investigated during a short summer field campaign performed in a citrus fruit field in northern Corsica (June 2011). Aimed at assessing the performance on the field of newly developed analytical protocols, this work focuses on the molecular composition of both gas and particulate phases and provides an insight into partitioning behavior of the semi-volatile oxygenated fraction. Limonene ozonolysis tracers were specifically searched for, according to gas chromatography-mass spectrometry (GC-MS) data previously recorded for smog chamber experiments. A screening of other oxygenated species present in the field atmosphere was also performed. About sixty polar molecules were positively or tentatively identified in gas and/or particle phases. These molecules comprise a wide range of branched and linear, mono and di-carbonyls (C3-C7), mono and di-carboxylic acids (C3-C18), and compounds bearing up to three functionalities. Among these compounds, some can be specifically attributed to limonene oxidation and others can be related to α- or β-pinene oxidation. This provides an original snapshot of the organic matter composition at a Mediterranean site in summer. Furthermore, for compounds identified and quantified in both gaseous and particulate phases, an experimental gas/particle partitioning coefficient was determined. Several volatile products, which are not expected in the particulate phase assuming thermodynamic equilibrium, were nonetheless present in significant concentrations. Hypotheses are proposed to explain these observations, such as the possible aerosol viscosity that could hinder the theoretical equilibrium to be rapidly reached. PMID:26969549

  10. Diurnal patterns in PM 2.5 mass and composition at a background, complex terrain site

    NASA Astrophysics Data System (ADS)

    Tanner, Roger L.; Bairai, Solomon T.; Olszyna, Kenneth J.; Valente, Myra L.; Valente, Ralph J.

    Current fine particle NAAQS specify 24 h integrated mass measurements as the compliance metric. However, the value of continuous short-time resolution sampling (1 h or less) is recognized and being included in US EPA-monitoring strategies. An extensive body of fine mass concentration data has been acquired using continuous PM 2.5 monitoring by TEOM at Look Rock, TN, augmented by trace gas measurements and, during enhanced monitoring periods, continuous sampling for aerosol sulfate (2 methods) and elemental (black) carbon. Continuous data are compared to the 24 h-averaged values of mass and composition from integrated samplers at the site, and for fine mass and sulfate are found to be excellent ( r2=0.97-0.99). We then report the diurnal variations in concentrations from extensive continuous monitoring during 3 summer periods (2000-2002) and for more limited periods throughout calendar year 2001. Levels of the several continuously measured gases and particulate constituents vary in magnitude diurnally according to expected patterns based on their emissions, their formation and loss processes, their lifetimes toward wet and dry deposition, the dynamics of up-slope—down-slope circulation, and solar-driven boundary layer growth and decay. Thus, concentrations of short-lifetime gases have minima at sunrise and maxima in the evening. Long-lived primary species (CO and black carbon) increase in mid-morning as the boundary layer height reaches the site and decay thereafter. Long-lived secondary species (sulfate and fine mass) show little diurnal variability. Factors controlling the observed diurnal variability thus significantly influence the extent and timing of human exposure to pollutant species, as well as affecting visibility impairment in complex terrain environments near the Great Smoky Mountains National Park.

  11. Molecular composition of organic aerosols at urban background and road tunnel sites using ultra-high resolution mass spectrometry.

    PubMed

    Tong, Haijie; Kourtchev, Ivan; Pant, Pallavi; Keyte, Ian J; O'Connor, Ian P; Wenger, John C; Pope, Francis D; Harrison, Roy M; Kalberer, Markus

    2016-07-18

    Organic aerosol composition in the urban atmosphere is highly complex and strongly influenced by vehicular emissions which vary according to the make-up of the vehicle fleet. Normalized test measurements do not necessarily reflect real-world emission profiles and road tunnels are therefore ideal locations to characterise realistic traffic particle emissions with minimal interference from other particle sources and from atmospheric aging processes affecting their composition. In the current study, the composition of fine particles (diameter ≤2.5 μm) at an urban background site (Elms Road Observatory Site) and a road tunnel (Queensway) in Birmingham, UK, were analysed with direct infusion, nano-electrospray ionisation ultrahigh resolution mass spectrometry (UHRMS). The overall particle composition at these two sites is compared with an industrial harbour site in Cork, Ireland, with special emphasis on oxidised mono-aromatics, polycyclic aromatic hydrocarbons (PAHs) and nitro-aromatics. Different classification criteria, such as double bond equivalents, aromaticity index and aromaticity equivalent are used and compared to assess the fraction of aromatic components in the approximately one thousand oxidized organic compounds at the different sampling locations. PMID:27143100

  12. Effects of short-term cattle exclusion on plant community composition: Prairie dog and ecological site influences

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant community composition is an important indicator of healthy, proper functioning rangelands. We evaluated the impacts prairie dog grazing, ecological site and short term cattle exclusion on Northern Mixed-Grass prairie near McLaughlin, SD. Modified Daubenmire frames provided canopy cover, litte...

  13. Flavor-violation tests of the warped/composite standard model in the two-site approach

    NASA Astrophysics Data System (ADS)

    Agashe, Kaustubh; Azatov, Aleksandr; Zhu, Lijun

    2009-03-01

    We study flavor violation in the quark sector in a purely 4D, two-site effective field theory description of the standard model (SM) and just their first Kaluza-Klein excitations from a warped extra dimension. The warped 5D framework can provide solutions to both the Planck-weak and flavor hierarchies of the SM. It is also related (via the AdS/CFT correspondence) to partial compositeness of the SM. We focus on the dominant contributions in the two-site model to two observables which we argue provide the strongest constraints from flavor violation, namely, γK and BR(b→sγ), where contributions in the two-site model occur at tree and loop-level, respectively. In particular, we demonstrate that a “tension” exists between these two observables in the sense that they have opposite dependence on composite site Yukawa couplings, making it difficult to decouple flavor-violating effects using this parameter. We choose the size of the composite site QCD coupling based on the relation of the two-site model to the 5D model (addressing the Planck-weak hierarchy), where we match the 5D QCD coupling to the 4D coupling at the loop-level and assuming negligible tree-level brane-localized kinetic terms. We estimate that a larger size of the 5D gauge coupling is constrained by the requirement of 5D perturbativity. We find that ˜O(5)TeV mass scale for the new particles in the two-site model can then be consistent with both observables. We also compare our analysis of γK in the two-site model to that in 5D models, including both the cases of a brane-localized and bulk Higgs.

  14. Technical Scope and Approach for the 2004 Composite Analysis of Low Level Waste Disposal at the Hanford Site

    SciTech Connect

    Kincaid, Charles T.; Bryce, Robert W.; Buck, John W.

    2004-07-09

    A composite analysis is required by U.S. Department of Energy (DOE) Manual 435.1-1 to ensure public safety through the management of active and planned low-level radioactive waste disposal facilities associated with the Hanford Site (DOE/HQ-Manual 435.1-1). A Composite Analysis is defined as ''a reasonably conservative assessment of the cumulative impact from active and planned low-level waste disposal facilities, and all other sources from radioactive contamination that could interact with the low-level waste disposal facility to affect the dose to future members of the public''. At the Hanford Site, a composite analysis is required for continued disposal authorization for the immobilized low-activity waste, tank waste vitrification plant melters, low level waste in the 200 East and 200 West Solid Waste Burial Grounds, and Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) waste in the Environmental Restoration Disposal Facility. The 2004 Composite Analysis will be a site-wide analysis, considering final remedial actions for the Columbia River corridor and the Central Plateau at the Hanford Site. The river corridor includes waste sites and facilities in each of the 100 Areas as well as the 300, 400, and 600 Areas. The remedial actions for the river corridor are being conducted to meet residential land use standards with the vision of the river corridor being devoted to a combination of recreation and preservation. The ''Central Plateau'' describes the region associated with operations and waste sites of the 200 Areas. DOE is developing a strategy for closure of the Central Plateau area by 2035. At the time of closure, waste management activities will shrink to a Core Zone within the Central Plateau. The Core Zone will contain the majority of Hanford's permanently disposed waste

  15. Chemical composition and mass closure of particulate matter at six urban sites in Europe

    NASA Astrophysics Data System (ADS)

    Sillanpää, Markus; Hillamo, Risto; Saarikoski, Sanna; Frey, Anna; Pennanen, Arto; Makkonen, Ulla; Spolnik, Zoya; Van Grieken, René; Braniš, Martin; Brunekreef, Bert; Chalbot, Marie-Cecile; Kuhlbusch, Thomas; Sunyer, Jordi; Kerminen, Veli-Matti; Kulmala, Markku; Salonen, Raimo O.

    The chemical composition of fine (PM 2.5) and coarse (PM 2.5-10) particulate matter was investigated in 7-week field campaigns of contrasting air pollution at six urban background sites in Europe. The campaigns were scheduled to include seasons of local public health concern due to high particulate concentrations or findings in previously conducted epidemiological studies. The sampling campaigns were carried out as follows: Duisburg/Germany October-November 2002 (autumn), Prague/Czech Republic November 2002-January 2003 (winter), Amsterdam/Netherlands January-March 2003 (winter), Helsinki/Finland March-May 2003 (spring), Barcelona/Spain March-May 2003 (spring) and Athens/Greece June-July 2003 (summer). Aerosol samples were collected in 3+4-day periods per week ( N=14) using two identical virtual impactors (VI). All the filter samples were analysed with the same instruments to obtain particulate mass, inorganic ions, total and watersoluble elements, and elemental and organic carbon content. The campaign means of PM 2.5 and PM 2.5-10 ranged from 8.3 to 30 and 5.4 to 29 μg m -3, respectively. The "wet and cool" seasons favoured a low coarse-to-fine particulate mass ratio (<1), whereas the ratio was high (>1) during the warmer and drier spring and summer campaigns. According to chemical mass closure, the major components in PM 2.5 were carbonaceous compounds (organic matter+elemental carbon), secondary inorganic ions and sea salt, whereas those in PM 2.5-10 were soil-derived compounds, carbonaceous compounds, sea salt and nitrate. The major and minor components together accounted for 79-106% and 77-96% of the gravimetrically measured PM 2.5 and PM 2.5-10 mass, respectively. In conclusion, the measured PM 2.5 and PM 2.5-10 in the campaigns could be reconstructed to a large extent with the help of harmonized particulate sampling and analysis of the selected chemical constituents. The health significance of the observed differences in chemical composition and emission

  16. Composite analysis for low-level waste disposal in the 200 area plateau of the Hanford Site

    SciTech Connect

    Kincaid, C.T.; Bergeron, M.P.; Cole, C.R.

    1998-03-01

    This report presents the first iteration of the Composite Analysis for Low-Level Waste Disposal in the 200 Area Plateau of the Hanford Site (Composite Analysis) prepared in response to the U.S. Department of Energy Implementation Plan for the Defense Nuclear Facility Safety Board Recommendation 94-2. The Composite Analysis is a companion document to published analyses of four active or planned low-level waste disposal actions: the solid waste burial grounds in the 200 West Area, the solid waste burial grounds in the 200 East Area, the Environmental Restoration Disposal Facility, and the disposal facilities for immobilized low-activity waste. A single Composite Analysis was prepared for the Hanford Site considering only sources on the 200 Area Plateau. The performance objectives prescribed in U.S. Department of Energy guidance for the Composite Analysis were 100 mrem in a year and examination of a lower dose (30 mrem in a year) to ensure the {open_quotes}as low as reasonably achievable{close_quotes} concept is followed. The 100 mrem in a year limit was the maximum allowable all-pathways dose for 1000 years following Hanford Site closure, which is assumed to occur in 2050. These performance objectives apply to an accessible environment defined as the area between a buffer zone surrounding an exclusive waste management area on the 200 Area Plateau, and the Columbia River. Estimating doses to hypothetical future members of the public for the Composite Analysis was a multistep process involving the estimation or simulation of inventories; waste release to the environment; migration through the vadose zone, groundwater, and atmospheric pathways; and exposure and dose. Doses were estimated for scenarios based on agriculture, residential, industrial, and recreational land use. The radionuclides included in the vadose zone and groundwater pathway analyses of future releases were carbon-14, chlorine-36, selenium-79, technetium-99, iodine-129, and uranium isotopes.

  17. Effect of Geopolymer filler in Glass Reinforced Epoxy (GRE) Pipe for Piping Application: Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Firdaus Abu Hashim, Mohammad; Bakri Abdullah, Mohd Mustafa Al; Mohd Ruzaidi Ghazali, Che; Hussin, Kamarudin; Binhussain, Mohammed

    2016-06-01

    The present work is aimed to carry out the effect of geopolymer material which is fly ash as filler in the glass reinforced epoxy pipe on the micro structure of fly ash geopolymer, compression properties, and bulk density using the filament winding method. Conventional glass reinforced epoxy pipes has its own disadvantages such as high corrosion resistance at acidic environment and low strength which can be replaced by the composite pipes. Geopolymer is a type of amorphous alumino-silicate and can be synthesized by geopolymerization process. A series of glass reinforced epoxy pipe and glass reinforced epoxy pipe filled with 10 - 40 weight percentage geopolymer filler which is fly ash with 4 Molarity were prepared. Morphology of the raw material fly ash and fly ash based-geopolymer surface was characterized using scanning electron microscopy. It was found that the additions of fly ash at the beginning with 10 wt% are showing higher compressive strength than glass reinforced epoxy pipe without fly ash geopolymer filler. The compressive test of these series of samples was determined using Instron Universal Testing under compression mode. It was found that compressive strength for samples fly ash based-geopolymer filler are higher as compared to glass reinforced epoxy pipe without geopolymer filler. However, the compressive strength of glass reinforced epoxy pipe with fly ash geopolymer filler continues to decline when added to 20 wt% - 40 wt% of geopolymer filler loading. The results showed that the mixing of geopolymer materials in epoxy system can be obtained in this study.

  18. Physical Properties and Chemical Composition of Aerosols sampled in T1 site during MILAGRO Campaign

    NASA Astrophysics Data System (ADS)

    Castro, T.; Mamani-Paco, R.; Saavedra, M. I.; Garcia, J.; Amador, O.; Carabali, G.; Salcido, A.; Herrera, E.; Baez, A.

    2007-05-01

    Results from pollutant measurements and meteorological variables corresponding to the month of March of 2006 during the MILAGRO campaign at site T1 are presented (Tecamac, State of Mexico). Three 8-stage cascade impactors (MOUDI) were employed to obtain aerosol samples of different sizes. For organic species analysis, samples were collected with a PM2.5 High Volume sampler. Mass and chemical composition (inorganic and organic species) were obtained with the use of analytical techniques. Particle morphology analysis was done with a TEM-EDAX System. Physical properties of aerosols were measured with a PSAP, a nephelometer and a CPC. According with area meteorology, days with Mexico City urban influence on T1 (March 9-12) and without influence (March 14 and 15) were analyzed. The particle average concentration during the whole campaign was 20,000 particles/cm3. For the days with and without urban influence the average concentrations were 17,500 and 8,000 particles/cm3 respectively. From the MOUDI data the highest particle concentration through the campaign was during the morning in the mode d50=0.32 μm. On the other hand, the cumulative highest concentration of all the stages was observed for March 19 followed by March 9. Scattering and absorption coefficients average obtained on T1 were 5.1x10-5 m-1 and 2.54x10-5 m-1 respectively and single scattering albedo was 0.676. These values show T1 as a polluted atmosphere, just as happens with megacities. Morphology of particles captured in a MOUDI impactor was studied. Particles between d50=0.18 μm and d50=1.8 μm sampled in T1 associated with urban influence (March 9) tended to show less irregular shapes through different periods of that day. These findings suggest the presence of large numbers of secondary aerosols and aged agglomerated particles. Particles ranging from d50=0.18 μm to d50=1.8 μm sampled in T1 and associated mainly with surrounding areas influence, e.g. Tizayuca Industrial Park (March 15) showed

  19. Site-specific specimen preparation by focused ion beam milling for transmission electron microscopy of metal matrix composites.

    PubMed

    Gasser, Philippe; Klotz, Ulrich E; Khalid, Fazal A; Beffort, Olivier

    2004-04-01

    This work describes the application and usefulness of the focused ion beam (FIB) technique for the preparation of transmission electron microscopy (TEM) samples from metal matrix composite materials. Results on an Aldiamond composite, manufactured by the squeeze casting infiltration process, were chosen for demonstration. It is almost impossible to prepare TEM specimens of this material by any other conventional method owing to the presence of highly inhomogeneous phases and reinforcement diamond particles. The present article gives a detailed account of the salient features of the FIB technique and its operation. One of the big advantages is the possibility to prepare site-specific TEM specimens with high spatial resolution. The artifacts occurring during the specimen preparation, for example, Ga-ion implantation, curtain effects, amorphous layers, bending of the lamella, or different milling behaviors of the materials have been discussed. Furthermore, TEM examination of the specimens prepared revealed an ultrafine amorphous layer of graphite formed at the interface between the Al and diamond particles that may affect the interfacial properties of the composite materials. This may not have been feasible without the successful application of the FIB technique for production of good quality site-specific TEM specimens. PMID:15306057

  20. Computational Identification of Protein Pupylation Sites by Using Profile-Based Composition of k-Spaced Amino Acid Pairs.

    PubMed

    Hasan, Md Mehedi; Zhou, Yuan; Lu, Xiaotian; Li, Jinyan; Song, Jiangning; Zhang, Ziding

    2015-01-01

    Prokaryotic proteins are regulated by pupylation, a type of post-translational modification that contributes to cellular function in bacterial organisms. In pupylation process, the prokaryotic ubiquitin-like protein (Pup) tagging is functionally analogous to ubiquitination in order to tag target proteins for proteasomal degradation. To date, several experimental methods have been developed to identify pupylated proteins and their pupylation sites, but these experimental methods are generally laborious and costly. Therefore, computational methods that can accurately predict potential pupylation sites based on protein sequence information are highly desirable. In this paper, a novel predictor termed as pbPUP has been developed for accurate prediction of pupylation sites. In particular, a sophisticated sequence encoding scheme [i.e. the profile-based composition of k-spaced amino acid pairs (pbCKSAAP)] is used to represent the sequence patterns and evolutionary information of the sequence fragments surrounding pupylation sites. Then, a Support Vector Machine (SVM) classifier is trained using the pbCKSAAP encoding scheme. The final pbPUP predictor achieves an AUC value of 0.849 in 10-fold cross-validation tests and outperforms other existing predictors on a comprehensive independent test dataset. The proposed method is anticipated to be a helpful computational resource for the prediction of pupylation sites. The web server and curated datasets in this study are freely available at http://protein.cau.edu.cn/pbPUP/. PMID:26080082

  1. Computational Identification of Protein Pupylation Sites by Using Profile-Based Composition of k-Spaced Amino Acid Pairs

    PubMed Central

    Lu, Xiaotian; Li, Jinyan; Song, Jiangning; Zhang, Ziding

    2015-01-01

    Prokaryotic proteins are regulated by pupylation, a type of post-translational modification that contributes to cellular function in bacterial organisms. In pupylation process, the prokaryotic ubiquitin-like protein (Pup) tagging is functionally analogous to ubiquitination in order to tag target proteins for proteasomal degradation. To date, several experimental methods have been developed to identify pupylated proteins and their pupylation sites, but these experimental methods are generally laborious and costly. Therefore, computational methods that can accurately predict potential pupylation sites based on protein sequence information are highly desirable. In this paper, a novel predictor termed as pbPUP has been developed for accurate prediction of pupylation sites. In particular, a sophisticated sequence encoding scheme [i.e. the profile-based composition of k-spaced amino acid pairs (pbCKSAAP)] is used to represent the sequence patterns and evolutionary information of the sequence fragments surrounding pupylation sites. Then, a Support Vector Machine (SVM) classifier is trained using the pbCKSAAP encoding scheme. The final pbPUP predictor achieves an AUC value of 0.849 in10-fold cross-validation tests and outperforms other existing predictors on a comprehensive independent test dataset. The proposed method is anticipated to be a helpful computational resource for the prediction of pupylation sites. The web server and curated datasets in this study are freely available at http://protein.cau.edu.cn/pbPUP/. PMID:26080082

  2. Effect of rotation, site, and clone on the chemical composition of Populus hybrids

    SciTech Connect

    Blanckenhorn, P.R.; Bowersox, T.W.; Kuklewski, K.M.; Stimely, S.L.

    1985-01-01

    Chemical content values were determined for three Populus clones grown on two dissimilar sites by component (wood, bark, and wood/bark specimens), tissue age (1-, 2- and 4-year-old), and rotation. The chemical content values obtained included extractives, holocellulose, ..alpha..-cellulose, and lignin. In general, analysis of the data for the wood, bark, and wood/bark specimens indicated that: 1) wood was high in holocellulose and ..alpha..-cellulose content compared to bark, 2) bark was high in lignin and extractive content values compared to wood, and 3) wood/bark chemical content values were between the values for the wood and bark specimens. The chemical content data were analyzed to identify: 1) significant differences between rotations by component (wood, bark and wood/bark) for a given age, clone, and site, and 2) significant differences between sites for four-year-old wood, bark and wood/bark specimens of a given rotation, and clone. Statistical analyses indicated that significant differences existed among clones, sites, ages, and rotations. Within the wood, bark and wood/bark specimens, tissue age, rotation, and site influenced the chemical content values more than the parentage. Potential chemical yields derived from the three Populus hybrid clones investigated will depend on component, age, rotation, and site with limited parentage effects.

  3. Effects of Re-vegetation on Herbaceous Species Composition and Biological Soil Crusts Development in a Coal Mine Dumping Site.

    PubMed

    Zhao, Yang; Zhang, Peng; Hu, Yigang; Huang, Lei

    2016-02-01

    Despite the critical roles of plant species' diversity and biological soil crusts (BSCs) in arid and semi-arid ecosystems, the restoration of the diversity of herbaceous species and BSCs are rarely discussed during the process of vegetation restoration of anthropogenically damaged areas in these regions. In this study, the herbaceous plant species composition, along with the BSCs coverage and thicknesses, was investigated at six different re-vegetation type sites, and the natural vegetation site of the Heidaigou open pit coal mine in China's Inner Mongolia Autonomous Region was used as a reference. The highest total species richness (16), as well as the species richness (4.4), occurred in the Tree and Herbaceous vegetation type site. The species composition similarities between the restored sites and the reference site were shown to be very low, and ranged from 0.09 to 0.42. Also, among the restored sites, the similarities of the species were fairly high and similar, and ranged from 0.45 to 0.93. The density and height of the re-vegetated woody plants were significantly correlated with the indexes of the diversity of the species. The Shrub vegetation type site showed the greatest total coverage (80%) of BSCs and algae crust coverage (48%). The Shrub and Herbaceous type had the greatest thicknesses of BSCs, with as much as 3.06 mm observed, which was followed by 2.64 mm for the Shrub type. There was a significant correlation observed between the coverage of the total BSCs, and the total vegetation and herbaceous vegetation coverage, as well as between the algae crust coverage and the herbaceous vegetation coverage. It has been suggested that the re-vegetated dwarf woody plant species (such as shrubs and semi-shrubs) should be chosen for the optimal methods of the restoration of herbaceous species diversity at dumping sites, and these should be planted with low density. Furthermore, the effects of vegetation coverage on the colonization and development the BSCs

  4. Effects of Re-vegetation on Herbaceous Species Composition and Biological Soil Crusts Development in a Coal Mine Dumping Site

    NASA Astrophysics Data System (ADS)

    Zhao, Yang; Zhang, Peng; Hu, Yigang; Huang, Lei

    2016-02-01

    Despite the critical roles of plant species' diversity and biological soil crusts (BSCs) in arid and semi-arid ecosystems, the restoration of the diversity of herbaceous species and BSCs are rarely discussed during the process of vegetation restoration of anthropogenically damaged areas in these regions. In this study, the herbaceous plant species composition, along with the BSCs coverage and thicknesses, was investigated at six different re-vegetation type sites, and the natural vegetation site of the Heidaigou open pit coal mine in China's Inner Mongolia Autonomous Region was used as a reference. The highest total species richness (16), as well as the species richness (4.4), occurred in the Tree and Herbaceous vegetation type site. The species composition similarities between the restored sites and the reference site were shown to be very low, and ranged from 0.09 to 0.42. Also, among the restored sites, the similarities of the species were fairly high and similar, and ranged from 0.45 to 0.93. The density and height of the re-vegetated woody plants were significantly correlated with the indexes of the diversity of the species. The Shrub vegetation type site showed the greatest total coverage (80 %) of BSCs and algae crust coverage (48 %). The Shrub and Herbaceous type had the greatest thicknesses of BSCs, with as much as 3.06 mm observed, which was followed by 2.64 mm for the Shrub type. There was a significant correlation observed between the coverage of the total BSCs, and the total vegetation and herbaceous vegetation coverage, as well as between the algae crust coverage and the herbaceous vegetation coverage. It has been suggested that the re-vegetated dwarf woody plant species (such as shrubs and semi-shrubs) should be chosen for the optimal methods of the restoration of herbaceous species diversity at dumping sites, and these should be planted with low density. Furthermore, the effects of vegetation coverage on the colonization and development the BSCs

  5. Analysis of the site-specific carbon isotope composition of propane by gas source isotope ratio mass spectrometer

    NASA Astrophysics Data System (ADS)

    Piasecki, Alison; Sessions, Alex; Lawson, Michael; Ferreira, A. A.; Neto, E. V. Santos; Eiler, John M.

    2016-09-01

    Site-specific isotope ratio measurements potentially provide valuable information about the formation and degradation of complex molecules-information that is lost in conventional bulk isotopic measurements. Here we discuss the background and possible applications of such measurements, and present a technique for studying the site-specific carbon isotope composition of propane at natural abundance based on mass spectrometric analysis of the intact propane molecule and its fragment ions. We demonstrate the feasibility of this approach through measurements of mixtures of natural propane and propane synthesized with site-specific 13C enrichment, and we document the limits of precision of our technique. We show that mass balance calculations of the bulk δ13C of propane based on our site-specific measurements is generally consistent with independent constraints on bulk δ13C. We further demonstrate the accuracy of the technique, and illustrate one of its simpler applications by documenting the site-specific carbon isotope signature associated with gas phase diffusion of propane, confirming that our measurements conform to the predictions of the kinetic theory of gases. This method can be applied to propane samples of moderate size (tens of micromoles) isolated from natural gases. Thus, it provides a means of studying the site-specific stable isotope systematics of propane at natural isotope abundances on sample sizes that are readily recovered from many natural environments. This method may also serve as a model for future techniques that apply high-resolution mass spectrometry to study the site-specific isotopic distributions of larger organic molecules, with potential applications to biosynthesis, forensics and other geochemical subjects.

  6. PM2.5 ORGANIC COMPOSITION FROM SEVERAL SITES IN THE UNITED STATES

    EPA Science Inventory

    Organic constituents make up an important component of fine particulate matter (PM2.5) in ambient environments. While part of the composition of organic aerosol results from emissions of primary sources, an additional component appears to come from gas-to-particle conversion o...

  7. Constraints on the origins of hydrocarbon gas from compositions of gases at their site of origin

    USGS Publications Warehouse

    Price, L.C.; Schoell, M.

    1995-01-01

    IT is widely accepted that natural gas is formed from thermal decomposition of both oil in reservoirs and, to a lesser extent, the organic matter in shales from which the oil was derived1-6. But laboratory pyrolysis experiments on shales do not reproduce the methane-rich composition typical of most gas reservoirs7, leading to suggestions7 that other mechanisms, such as transition-metal catalysis, may be important. The discrepancy might, however, instead arise because gas (and oil) deposits have migrated from their source rocks, so that the reservoir composition might not be representative of the composition in the source rocks where the hydrocarbons were generated. To address this question, we have analysed gas samples coproduced with oils directly from a source rock (the Bakken shales, North Dakota, USA) where the local geology has prevented significant hydrocarbon migration. The methane contents of these Bakken-shale gases are much lower than that of conventional gas reservoirs, but are consistent with that from pyrolysis experiments8,9 on these shales. Thus, because these Bakken gases form with (rather than from) oils, we argue that compositional differences between gases from source rocks and conventional gas deposits result from fractionation processes occurring after hydrocarbon expulsion from the source rock.

  8. Constraints on the origins of hydrocarbon gas from compositions of gases at their site of origin

    PubMed

    Price, L C; Schoell, M

    1995-11-23

    It is widely accepted that natural gas is formed from thermal decomposition of both oil in reservoirs and, to a lesser extent, the organic matter in shales from which the oil was derived. But laboratory pyrolysis experiments on shales do not reproduce the methane-rich composition typical of most gas reservoirs, leading to suggestions that other mechanisms, such as transition-metal catalysis, may be important. The discrepancy might, however, instead arise because gas (and oil) deposits have migrated from their source rocks, so that the reservoir composition might not be representative of the composition in the source rocks where the hydrocarbons were generated. To address this question, we have analysed gas samples coproduced with oils directly from a source rock (the Bakken shales, North Dakota, USA) where the local geology has prevented significant hydrocarbon migration. The methane contents of these Bakken-shale gases are much lower than that of conventional gas reservoirs, but are consistent with that from pyrolysis experiments on these shales. Thus, because these Bakken gases form with (rather than from) oils, we argue that compositional differences between gases from source rocks and conventional gas deposits result from fractionation processes occurring after hydrocarbon expulsion from the source rock. PMID:11536709

  9. Maintenance Plan for the Performance Assessments and Composite Analyses for the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada Test Site

    SciTech Connect

    V. Yucel

    2002-09-01

    U.S. Department of Energy (DOE) Order 435.1 requires that performance assessments (PAs) and composite analyses (CAs) for low-level waste (LLW) disposal facilities be maintained by the field offices. This plan describes the activities to be performed in maintaining the Performance Assessment (PA) and Composite Analysis (CA) for the Area 3 and Area 5 Radioactive Waste Management Sites (RWMSs) at the Nevada Test Site (NTS). The Disposal Authorization Statement (DAS) for the continuing operations of a LLW facility at the DOE complex specifies the conditions for operations based on approval of a PA and CA, and requires the facility to implement a maintenance program to assure that these conditions will remain protective of the public health and the environment in the future. The goal of the maintenance program is to provide that assurance. The maintenance process is an iterative one in which changing conditions may result in a revision of PA and CA; the revised PA and CA may impose a different set of conditions for facility operation, closure, and postclosure. The maintenance process includes managing uncertainty, performing annual reviews, submitting annual summary reports to DOE Headquarters (DOE/HQ), carrying out special analyses, and revising the PAs and CAs, if necessary. Management of uncertainty is an essential component of the maintenance program because results of the original PAs and CAs are understood to be based on uncertain assumptions about the conceptual models; the mathematical models and parameters; and the future state of the lands, disposal facilities, and human activities. The annual reviews for the PAs include consideration of waste receipts, facility specific factors, results of monitoring, and results of research and development (R&D) activities. Likewise, results of ongoing R&D, changes in land-use planning, new information on known sources of residual radioactive materials, and identification of new sources may warrant an evaluation to determine

  10. Prediction of Initiation Site of Destruction of Flat Braided Carbon Fiber Composites Using HTS-SQUID Gradiometer

    NASA Astrophysics Data System (ADS)

    Shinyama, Y.; Hatsukade, Y.; Tanaka, S.; Takai, Y.; Aly-Hassan, M. S.; Nakai, A.; Hamada, H.

    Carbon fiber reinforced polymers (CFRPs) are composite materials with lightweight and high specific strength. As the braided CFRPs have continuous carbon-fiber bundles in their longitudinal direction, they are stronger than conventional CFRPs. In this study, we applied a current-injection-based NDE method using a HTS-SQUID gradiometer to the flat braided CFRPs with and without carbon nanotubes (CNTs), and estimated conditions of the carbon fibers while applying a step-by-step tensile load to the CFRPs. From the results, a possibility to predict an initiation site of the destruction in the braided CFRPs was demonstrated.

  11. Composition.

    ERIC Educational Resources Information Center

    Nemanich, Donald, Ed.

    1974-01-01

    The articles in this special issue of the "Illinois English Bulletin" concern the state of composition instruction at the secondary and college levels. The titles and authors are "Monologues or Dialogues? A Plea for Literacy" by Dr. Alfred J. Lindsey, "Teaching Composition: Curiouser and Curiouser" by Denny Brandon, and "Teaching Writing to High…

  12. Site occupancy and glycan compositional analysis of two soluble recombinant forms of the attachment glycoprotein of Hendra virus.

    PubMed

    Colgrave, Michelle L; Snelling, Hayley J; Shiell, Brian J; Feng, Yan-Ru; Chan, Yee-Peng; Bossart, Katharine N; Xu, Kai; Nikolov, Dimitar B; Broder, Christopher C; Michalski, Wojtek P

    2012-04-01

    Hendra virus (HeV) continues to cause morbidity and mortality in both humans and horses with a number of sporadic outbreaks. HeV has two structural membrane glycoproteins that mediate the infection of host cells: the attachment (G) and the fusion (F) glycoproteins that are essential for receptor binding and virion-host cell membrane fusion, respectively. N-linked glycosylation of viral envelope proteins are critical post-translation modifications that have been implicated in roles of structural integrity, virus replication and evasion of the host immune response. Deciphering the glycan composition and structure on these glycoproteins may assist in the development of glycan-targeted therapeutic intervention strategies. We examined the site occupancy and glycan composition of recombinant soluble G (sG) glycoproteins expressed in two different mammalian cell systems, transient human embryonic kidney 293 (HEK293) cells and vaccinia virus (VV)-HeLa cells, using a suite of biochemical and biophysical tools: electrophoresis, lectin binding and tandem mass spectrometry. The N-linked glycans of both VV and HEK293-derived sG glycoproteins carried predominantly mono- and disialylated complex-type N-glycans and a smaller population of high mannose-type glycans. All seven consensus sequences for N-linked glycosylation were definitively found to be occupied in the VV-derived protein, whereas only four sites were found and characterized in the HEK293-derived protein. We also report, for the first time, the existence of O-linked glycosylation sites in both proteins. The striking characteristic of both proteins was glycan heterogeneity in both N- and O-linked sites. The structural features of G protein glycosylation were also determined by X-ray crystallography and interactions with the ephrin-B2 receptor are discussed. PMID:22171062

  13. Sea urchin larvae decipher the epiphytic bacterial community composition when selecting sites for attachment and metamorphosis.

    PubMed

    Nielsen, Shaun J; Harder, Tilmann; Steinberg, Peter D

    2015-01-01

    Most marine invertebrates have dispersive larvae and relatively immobile adults. These developmental stages are linked by a settlement event, which is often mediated by specific cues in bacterial biofilms. While larvae distinguish between biofilms from different environments, it remains unknown if they receive information from all, only a few or even just a single bacterial species in natural biofilms. Here we asked how specific is larval settlement to the bacterial community structure and/or taxonomically distinguishable groups of bacteria in epiphytic marine biofilms? We used novel multivariate statistical approaches to investigate if larval settlement of two sea urchins correlated with the microbial community composition. Larval settlement of Heliocidaris erythrogramma revealed a strong correlation with the community composition, highlighted by canonical analysis of principle components, a constrained ordination technique. Using this technique, the importance of operational taxonomic units (OTUs) within communities relative to larval settlement was investigated. Larval settlement not only correlated, both positively and negatively, with the epiphytic bacterial community composition but also with the relative abundance of few OTUs within these communities. In contrast, no such correlation was observed for the other urchin, Holopneustes purpurascens, whose larvae likely respond to bacterial biofilms in a more general way and specifically respond to a defined settlement cue of algal origin. PMID:25764535

  14. Delineation of surf scoter habitat in Chesapeake Bay, Maryland: macrobenthic and sediment composition of surf scoter feeding sites

    USGS Publications Warehouse

    Kidwell, D.M.; Perry, M.C.

    2005-01-01

    Surveys of surf scoters (Melanitta perspicillata) along the Atlantic coast of the United States have shown population declines in recent decades. The Chesapeake Bay has traditionally been a key wintering area for surf scoters. Past and present research has shown that bivalves constitute a major food item for seaducks in the Chesapeake Bay, with surf scoters feeding primarily on hooked mussel (Ischadium recurvum) and dwarf surf clam (Mulinia lateralis). Degraded water quality conditions in the Chesapeake Bay have been well documented and have been shown to greatly influence the composition of benthic communities. Large concentrations of feeding surf scoters (>500 individuals) in the Bay were determined through monthly boat surveys. Locations consistently lacking surf scoters were also determined. Macrobenthos were seasonally sampled at 3 locations containing scoters and 3 locations without scoters. A 1 kilometer square grid was superimposed over each location using GIS and sampling sites within the square were randomly chosen. Benthos were sampled at each site using SCUBA and a meter square quadrat. Biomass and size class estimates were determined for all bivalves within each kilometer square. Results indicated that scoter feeding sites contained significantly greater biomass of M. lateralis, I. recurvum, and Gemma gemma than locations where no scoters were present. Substrate differences were also detected, with scoter feeding sites being composed of a sand/shell mix while non-scoter sites consisted primarily of mud. This data indicates that surf scoters in the Chesapeake Bay are selecting areas with high densities of preferred food items, potentially maximizing there foraging energetics. In addition, two scoter feeding sites also contained a patchwork of eastern oyster (Crassostrea virginica) and oyster shell, on which much of the I. recurvum was attached. This suggests the possibility that surf scoters utilize eastern oyster habitat and the dramatic depletion of

  15. Composition and sources of carbonaceous aerosols at three contrasting sites in Hong Kong

    NASA Astrophysics Data System (ADS)

    Zheng, Mei; Hagler, Gayle S. W.; Ke, Lin; Bergin, Michael H.; Wang, Fu; Louie, Peter K. K.; Salmon, Lynn; Sin, Della W. M.; Yu, Jian Zhen; Schauer, James J.

    2006-10-01

    A significant fraction of the fine particulate matter in Hong Kong is made up of organic carbon. In order to quantitatively assess the contributions of various sources to carbonaceous aerosol in Hong Kong, a chemical mass balance (CMB) receptor model in combination with organic tracers was employed. Organic tracers including n-alkanes, polycyclic aromatic hydrocarbons (PAHs), steranes, hopanes, resin acids, cholesterol, levoglucosan, and picene in PM2.5 collected from three air monitoring sites located at roadside, urban, and rural areas in Hong Kong are quantified using gas chromatography-mass spectrometry (GC/MS) in the present study. Analyses of some overlapping species from two separate laboratories will be compared for the first time. Spatial and seasonal source contributions to organic carbon (OC) in PM2.5 from up to nine air pollution sources are assessed, including diesel engine exhaust, gasoline engine exhaust, meat cooking, cigarette smoke, biomass burning, road dust, vegetative detritus, coal combustion, and natural gas combustion. Diesel engine exhaust dominated fine organic carbon in Hong Kong (57 ± 13% at urban sites and 25 ± 2% at the rural site). Other sources that play an important role are meat cooking and biomass burning, which can account for as much as 14% of fine organic carbon. The primary sources identified by this technique explained 49%, 79%, and 94% of the measured fine organic carbon mass concentration at the rural, the urban, and the roadside sites, respectively. The unexplained fine OC is likely due to secondary organic aerosol formation.

  16. Composition and Antigenic Effects of Individual Glycan Sites of a Trimeric HIV-1 Envelope Glycoprotein

    PubMed Central

    Behrens, Anna-Janina; Vasiljevic, Snezana; Pritchard, Laura K.; Harvey, David J.; Andev, Rajinder S.; Krumm, Stefanie A.; Struwe, Weston B.; Cupo, Albert; Kumar, Abhinav; Zitzmann, Nicole; Seabright, Gemma E.; Kramer, Holger B.; Spencer, Daniel I.R.; Royle, Louise; Lee, Jeong Hyun; Klasse, Per J.; Burton, Dennis R.; Wilson, Ian A.; Ward, Andrew B.; Sanders, Rogier W.; Moore, John P.; Doores, Katie J.; Crispin, Max

    2016-01-01

    Summary The HIV-1 envelope glycoprotein trimer is covered by an array of N-linked glycans that shield it from immune surveillance. The high density of glycans on the trimer surface imposes steric constraints limiting the actions of glycan-processing enzymes, so that multiple under-processed structures remain on specific areas. These oligomannose glycans are recognized by broadly neutralizing antibodies (bNAbs) that are not thwarted by the glycan shield but, paradoxically, target it. Our site-specific glycosylation analysis of a soluble, recombinant trimer (BG505 SOSIP.664) maps the extremes of simplicity and diversity of glycan processing at individual sites and reveals a mosaic of dense clusters of oligomannose glycans on the outer domain. Although individual sites usually minimally affect the global integrity of the glycan shield, we identify examples of how deleting some glycans can subtly influence neutralization by bNAbs that bind at distant sites. The network of bNAb-targeted glycans should be preserved on vaccine antigens. PMID:26972002

  17. Magnesium isotopic compositions of altered oceanic basalts and gabbros from IODP site 1256 at the East Pacific Rise

    NASA Astrophysics Data System (ADS)

    Huang, Jian; Ke, Shan; Gao, Yongjun; Xiao, Yilin; Li, Shuguang

    2015-08-01

    To investigate the behaviour of Mg isotopes during alteration of oceanic crust and constrain the Mg isotopic compositions of the altered oceanic crust (AOC), high-precision Mg isotope analyses have been conducted on forty-four altered basalts and gabbros recovered from IODP site 1256, which represent the carbonate-barren AOC formed at the East Pacific Rise (EPR). These samples were altered by interaction of seawater-derived fluids with oceanic crust at different temperatures and water/rock ratios. With the exception of one sample that has a slightly heavier Mg isotopic composition (δ26Mg = 0.01 ± 0.08‰), all the other samples have relatively homogenous and mantle-like Mg isotopic compositions, with δ26Mg ranging from - 0.36 to - 0.14‰ (an average value of - 0.25 ± 0.11‰, 2SD, n = 43). This suggests that limited Mg isotope fractionation occurred during alteration of oceanic crust at the EPR at bulk rock scale, irrespective of highly variable alteration temperatures and variable water/rock ratios. Thus, our study suggests that the offset of δ26Mg values between seawater and global runoff dominantly results from the formation of marine dolomite as a sink for Mg. The mantle-like Mg isotopic composition further indicates that recycling of carbonate-barren AOC would not result in Mg isotope heterogeneity of the mantle at global scale. Consequently, the light Mg isotopic compositions of the mantle at local scale must result from incorporation of recycled Mg isotopically light carbonates.

  18. Wolbachia Transcription Elongation Factor “Wol GreA” Interacts with α2ββ′σ Subunits of RNA Polymerase through Its Dimeric C-Terminal Domain

    PubMed Central

    Nag, Jeetendra Kumar; Shrivastava, Nidhi; Chahar, Dhanvantri; Gupta, Chhedi Lal; Bajpai, Preeti; Misra-Bhattacharya, Shailja

    2014-01-01

    Objectives Wolbachia, an endosymbiont of filarial nematode, is considered a promising target for therapy against lymphatic filariasis. Transcription elongation factor GreA is an essential factor that mediates transcriptional transition from abortive initiation to productive elongation by stimulating the escape of RNA polymerase (RNAP) from native prokaryotic promoters. Upon screening of 6257 essential bacterial genes, 57 were suggested as potential future drug targets, and GreA is among these. The current study emphasized the characterization of Wol GreA with its domains. Methodology/Principal Findings Biophysical characterization of Wol GreA with its N-terminal domain (NTD) and C-terminal domain (CTD) was performed with fluorimetry, size exclusion chromatography, and chemical cross-linking. Filter trap and far western blotting were used to determine the domain responsible for the interaction with α2ββ′σ subunits of RNAP. Protein-protein docking studies were done to explore residual interaction of RNAP with Wol GreA. The factor and its domains were found to be biochemically active. Size exclusion and chemical cross-linking studies revealed that Wol GreA and CTD exist in a dimeric conformation while NTD subsists in monomeric conformation. Asp120, Val121, Ser122, Lys123, and Ser134 are the residues of CTD through which monomers of Wol GreA interact and shape into a dimeric conformation. Filter trap, far western blotting, and protein-protein docking studies revealed that dimeric CTD of Wol GreA through Lys82, Ser98, Asp104, Ser105, Glu106, Tyr109, Glu116, Asp120, Val121, Ser122, Ser127, Ser129, Lys140, Glu143, Val147, Ser151, Glu153, and Phe163 residues exclusively participates in binding with α2ββ′σ subunits of polymerase. Conclusions/Significance To the best of our knowledge, this research is the first documentation of the residual mode of action in wolbachial mutualist. Therefore, findings may be crucial to understanding the transcription mechanism of

  19. Subunit composition determines E2F DNA-binding site specificity.

    PubMed Central

    Tao, Y; Kassatly, R F; Cress, W D; Horowitz, J M

    1997-01-01

    The product of the retinoblastoma (Rb) susceptibility gene, Rb-1, regulates the activity of a wide variety of transcription factors, such as E2F, in a cell cycle-dependent fashion. E2F is a heterodimeric transcription factor composed of two subunits each encoded by one of two related gene families, denoted E2F and DP. Five E2F genes, E2F-1 through E2F-5, and two DP genes, DP-1 and DP-2, have been isolated from mammals, and heterodimeric complexes of these proteins are expressed in most, if not all, vertebrate cells. It is not yet clear whether E2F/DP complexes regulate overlapping and/or specific cellular genes. Moreover, little is known about whether Rb regulates all or a subset of E2F-dependent genes. Using recombinant E2F, DP, and Rb proteins prepared in baculovirus-infected cells and a repetitive immunoprecipitation-PCR procedure (CASTing), we have identified consensus DNA-binding sites for E2F-1/DP-1, E2F-1/DP-2, E2F-4/DP-1, and E2F-4/DP-2 complexes as well as an Rb/E2F-1/DP-1 trimeric complex. Our data indicate that (i) E2F, DP, and Rb proteins each influence the selection of E2F-binding sites; (ii) E2F sites differ with respect to their intrinsic DNA-bending properties; (iii) E2F/DP complexes induce distinct degrees of DNA bending; and (iv) complex-specific E2F sites selected in vitro function distinctly as regulators of cell cycle-dependent transcription in vivo. These data indicate that the specific sequence of an E2F site may determine its role in transcriptional regulation and suggest that Rb/E2F complexes may regulate subsets of E2F-dependent cellular genes. PMID:9372931

  20. GR SUMOylation and formation of an SUMO-SMRT/NCoR1-HDAC3 repressing complex is mandatory for GC-induced IR nGRE-mediated transrepression.

    PubMed

    Hua, Guoqiang; Paulen, Laetitia; Chambon, Pierre

    2016-02-01

    Unique among the nuclear receptor superfamily, the glucocorticoid (GC) receptor (GR) can exert three distinct transcriptional regulatory functions on binding of a single natural (cortisol in human and corticosterone in mice) and synthetic [e.g., dexamethasone (Dex)] hormone. The molecular mechanisms underlying GC-induced positive GC response element [(+)GRE]-mediated activation of transcription are partially understood. In contrast, these mechanisms remain elusive for GC-induced evolutionary conserved inverted repeated negative GC response element (IR nGRE)-mediated direct transrepression and for tethered indirect transrepression that is mediated by DNA-bound NF-κB/activator protein 1 (AP1)/STAT3 activators and instrumental in GC-induced anti-inflammatory activity. We demonstrate here that SUMOylation of lysine K293 (mouse K310) located within an evolutionary conserved sequence in the human GR N-terminal domain allows the formation of a GR-small ubiquitin-related modifiers (SUMOs)-NCoR1/SMRT-HDAC3 repressing complex mandatory for GC-induced IR nGRE-mediated direct repression in vitro, but does not affect transactivation. Importantly, these results were validated in vivo: in K310R mutant mice and in mice ablated selectively for nuclear receptor corepressor 1 (NCoR1)/silencing mediator for retinoid or thyroid-hormone receptors (SMRT) corepressors in skin keratinocytes, Dex-induced direct repression and the formation of repressing complexes on IR nGREs were impaired, whereas transactivation was unaffected. In mice selectively ablated for histone deacetylase 3 (HDAC3) in skin keratinocytes, GC-induced direct repression, but not bindings of GR and of corepressors NCoR1/SMRT, was abolished, indicating that HDAC3 is instrumental in IR nGRE-mediated repression. Moreover, we demonstrate that the binding of HDAC3 to IR nGREs in vivo is mediated through interaction with SMRT/NCoR1. We also show that the GR ligand binding domain (LBD) is not required for SMRT

  1. Isotopic composition of water from a mine drainage site in Creede County in south central Colorado

    NASA Astrophysics Data System (ADS)

    Michel, R. L.; Williams, M. W.; Krupicka, A.; Wireman, M.; Graves, J.

    2011-12-01

    Creede County in South Central Colorado was an active area of silver mining beginning in the early 1890s. To relieve flooding in some of the mines, the Nelson Tunnel was built in the late 1890s. This tunnel still exists and acid mine drainage from the tunnel eventually flows into the Willow Creek Watershed which eventually flows into the Upper Rio Grande. The water coming out of the tunnel is high in toxic metals and the area has become part of an EPA Superfund site in an effort to find a suitable method to remediate the metal problems. Among the approaches used in the program is the use of isotopes of water and carbon to identify sources and estimate ages of the water in the drainage. Samples were collected for analysis of isotopic ratios and tritium concentrations at a series of sites within the tunnel complex from 2008-2010. In 2009 samples were also collected for analysis of isotopes in groundwater and surface water. In 2010 sampling was expanded to include four precipitation and one snow sample. Tritium concentrations in precipitation and snowfall in 2010 ranged from 3-6 tritium units with the lowest concentration found in the snow sample. The 18O isotopic ratios in precipitation for this site ranged from an average of -8.9 o/oo in summer to about -19 o/oo in winter. The six groundwater samples collected in 2009 had an average 18O isotopic concentration of -15 o/oo and tritium concentrations ranging from 7.4-9.3 TU. These results suggest that the groundwater sampled is composed largely of a mixture of summer and winter precipitation with the latter source being dominant. The tritium concentrations in groundwater exceed recent precipitation concentrations, suggesting the presence of water from the bomb-tritium transient and an age of a decade or more for the groundwater. Eight sites in the tunnel were sampled I from 2008-2010, although not all sites were sampled every year. The sampling sites included waters seeping into the tunnel as well as the outlet water

  2. Igneous and Sedimentary Compositions from Four Landing Sites on Mars from the Alpha Particle X-Ray Spectrometer (APXS)

    NASA Technical Reports Server (NTRS)

    Gellert, R.; Arvidson, R. E.; Clark, B. C.; Ming, D. W.; Mittlefehldt, D. W.; Morris, R. W.; Squyres, S. W.; VanBommel, S.; Yen, A. S.

    2016-01-01

    The APXS - supported and promoted strongly by Heinrich Waenke - on all four Mars Rovers has returned compositional data from about 1000 rocks and soil targets along the combined traverses of over 60 kilometers. Providing precise and accurate bulk chemistry with typically 16 quantified elements, the APXS is a powerful and versatile tool that when combined with the ability to traverse to key rocks and soils has provided critical information needed to understand the geologic evolution of Mars. APXS data allow comparisons among landing sites, provide ground truth for orbiters and connections back to SNC meteorites. The soils and dust are basaltic in character and represent the average Mars composition similar to Adirondack basalts from Gusev crater but with unambiguous elevated and correlated S, Cl and Zn contents. At all four landing sites the APXS found several rocks with a felsic composition. The similarity is best assessed in a logarithmic ratio plot of rock normalized to the average soil composition (Fig.1). High alkaline, Al, and low Mg, Fe, low S, Cl and Ni, Zn as well as an Fe/Mn ratio of approximately 50 indicate a likely unaltered and igneous origin. Sediments, e.g. the Burns formation, with approximately 25 wt% SO3 at Meridiani Planum have been documented over 10s of kilometers (Fig. 2). This formation is compositionally homogeneous, but showing the removal of MgSO4 and a threefold increase in Cl downhill in 2 craters. The degraded rim of the Noachian crater Endeavour resembles average Mars crust, with local Ca, Mg and Fe sulfate alteration and elevated Mn, some felsic rocks, and high Al, Si and low Fe rocks, possibly indicating clays. Unusual soils at Gusev crater in the area surrounding Home Plate include some very rich in ferric sulfate salts (up to 35 wt% SO3) and some with 90% wt% SiO2, possibly indicating fumerolic activities. Rocks in the Columbia Hills show significant signs of alteration including elevated S, Cl and Br in the abraded interior. At

  3. A Graphene Composite Material with Single Cobalt Active Sites: A Highly Efficient Counter Electrode for Dye-Sensitized Solar Cells.

    PubMed

    Cui, Xiaoju; Xiao, Jianping; Wu, Yihui; Du, Peipei; Si, Rui; Yang, Huaixin; Tian, Huanfang; Li, Jianqi; Zhang, Wen-Hua; Deng, Dehui; Bao, Xinhe

    2016-06-01

    The design of catalysts that are both highly active and stable is always challenging. Herein, we report that the incorporation of single metal active sites attached to the nitrogen atoms in the basal plane of graphene leads to composite materials with superior activity and stability when used as counter electrodes in dye-sensitized solar cells (DSSCs). A series of composite materials based on different metals (Mn, Fe, Co, Ni, and Cu) were synthesized and characterized. Electrochemical measurements revealed that CoN4 /GN is a highly active and stable counter electrode for the interconversion of the redox couple I(-) /I3 (-) . DFT calculations revealed that the superior properties of CoN4 /GN are due to the appropriate adsorption energy of iodine on the confined Co sites, leading to a good balance between adsorption and desorption processes. Its superior electrochemical performance was further confirmed by fabricating DSSCs with CoN4  /GN electrodes, which displayed a better power conversion efficiency than the Pt counterpart. PMID:27089044

  4. Measurements of dew and fog chemical composition at a rural site

    NASA Astrophysics Data System (ADS)

    Straub, D.; Sokoloff, R.; Ressler, D.; Herckes, P.

    2012-12-01

    Liquid water in the atmosphere has been shown to play an important role in the transport, transformation, and removal of aerosol particles and soluble gases. Dew and fog represent two forms of the atmospheric aqueous phase, both of which may enhance the deposition of trace species and enable fast aqueous phase reactions. Compared to precipitation, dews and fogs have longer residence times at ground level and therefore may be strongly influenced by local sources. Fog composition measurements in the United States have been limited to relatively few locations along the East and West coasts while only a handful of studies have focused on dew composition. To extend our knowledge of dew and fog composition, measurements have been made on the campus of Susquehanna University in central Pennsylvania. Fog samples have been collected since 2007 using an automated Caltech Heated Rod Cloudwater Collector (CHRCC). Dew sampling began during the summer of 2012 using a 90 cm by 90 cm Teflon sheet mounted on a polystyrene foam panel. All samples were analyzed for pH and one of more of the following: major inorganic ions, organic acids, total organic carbon (TOC), and trace metals. Dew and fog concentrations varied widely between samples, though concentrations of most species in fog generally exceeded those in dew. The median pH was approximately 6.0 for fog and 7.0 for dew, both of which are much higher than the median value of 4.6 for precipitation in this region. Ammonium was the most abundant ionic species in the fog samples, followed by sulfate, calcium, and nitrate. Dew samples were also dominated by ammonium, though calcium was significant in some samples. Sulfate and nitrate concentrations were substantially lower in the dew samples. Formate and acetate were the most abundant organic acids in both types of samples, although those species made up much larger fraction of the total solute in the dew samples. In addition, oxalate and propionate were observed in both types of

  5. Localization of binding sites in protein structures by optimization of a composite scoring function.

    PubMed

    Rossi, Andrea; Marti-Renom, Marc A; Sali, Andrej

    2006-10-01

    The rise in the number of functionally uncharacterized protein structures is increasing the demand for structure-based methods for functional annotation. Here, we describe a method for predicting the location of a binding site of a given type on a target protein structure. The method begins by constructing a scoring function, followed by a Monte Carlo optimization, to find a good scoring patch on the protein surface. The scoring function is a weighted linear combination of the z-scores of various properties of protein structure and sequence, including amino acid residue conservation, compactness, protrusion, convexity, rigidity, hydrophobicity, and charge density; the weights are calculated from a set of previously identified instances of the binding-site type on known protein structures. The scoring function can easily incorporate different types of information useful in localization, thus increasing the applicability and accuracy of the approach. To test the method, 1008 known protein structures were split into 20 different groups according to the type of the bound ligand. For nonsugar ligands, such as various nucleotides, binding sites were correctly identified in 55%-73% of the cases. The method is completely automated (http://salilab.org/patcher) and can be applied on a large scale in a structural genomics setting. PMID:16963645

  6. Localization of binding sites in protein structures by optimization of a composite scoring function

    PubMed Central

    Rossi, Andrea; Marti-Renom, Marc A.; Sali, Andrej

    2006-01-01

    The rise in the number of functionally uncharacterized protein structures is increasing the demand for structure-based methods for functional annotation. Here, we describe a method for predicting the location of a binding site of a given type on a target protein structure. The method begins by constructing a scoring function, followed by a Monte Carlo optimization, to find a good scoring patch on the protein surface. The scoring function is a weighted linear combination of the z-scores of various properties of protein structure and sequence, including amino acid residue conservation, compactness, protrusion, convexity, rigidity, hydrophobicity, and charge density; the weights are calculated from a set of previously identified instances of the binding-site type on known protein structures. The scoring function can easily incorporate different types of information useful in localization, thus increasing the applicability and accuracy of the approach. To test the method, 1008 known protein structures were split into 20 different groups according to the type of the bound ligand. For nonsugar ligands, such as various nucleotides, binding sites were correctly identified in 55%–73% of the cases. The method is completely automated (http://salilab.org/patcher) and can be applied on a large scale in a structural genomics setting. PMID:16963645

  7. Chemical, multispectral, and textural constraints on the composition and origin of rocks at the Mars Pathfinder landing site

    USGS Publications Warehouse

    McSween, H.Y., Jr.; Murchie, S.L.; Crisp, J.A.; Bridges, N.T.; Anderson, R.C.; Bell, J.F., III; Britt, D.T.; Brückner, J.; Dreibus, G.; Economou, T.; Ghosh, A.; Golombek, M.P.; Greenwood, J.P.; Johnson, J. R.; Moore, H.J.; Morris, R.V.; Parker, T.J.; Rieder, R.; Singer, R.; Wänke, H.

    1999-01-01

    Rocks at the Mars Pathfinder site are probably locally derived. Textures on rock surfaces may indicate volcanic, sedimentary, or impact-generated rocks, but aeolian abration and dust coatings prevent unambiguous interpretation. Multispectral imaging has resolved four spectral classes of rocks: gray and red, which occur on different surfaces of the same rocks; pink, which is probably soil crusts; and maroon, which occurs as large boulders, mostly in the far field. Rocks are assigned to two spectral trends based on the position of peak reflectance: the primary spectral trend contains gray, red, and pink rocks; maroon rocks constitute the secondary spectral trend. The spatial pattern of spectral variations observed is oriented along the prevailing wind direction. The primary spectral trend arises from thin ferric coatings of aeolian dust on darker rocks. The secondary spectral trend is apparently due to coating by a different mineral, probably maghemite or ferrihydrite. A chronology based on rock spectra suggests that rounded maroon boulders constitute the oldest petrologic unit (a flood deposit), succeeded by smaller cobbles possibly deposited by impact, and followed by aeolian erosion and deposition. Nearly linear chemical trends in alpha proton X-ray spectrometer rock compositions are interpreted as mixing lines between rock and adhering dust, a conclusion supported by a correlation between sulfur abundance and red/blue spectral ratio. Extrapolations of regression lines to zero sulfur give the composition of a presumed igneous rock. The chemistry and normative mineralogy of the sulfur-free rock resemble common terrestrial volcanic rocks, and its classification corresponds to andesite. Igneous rocks of this composition may occur with clastic sedimentary rocks or impact melts and breccias. However, the spectral mottling expected on conglomerates or breccias is not observed in any APXS-analyzed rocks. Interpretation of the rocks as andesites is complicated by absence

  8. Ferromanganese nodules from MANOP Sites H, S, and R-Control of mineralogical and chemical composition by multiple accretionary processes

    USGS Publications Warehouse

    Dymond, J.; Lyle, M.; Finney, B.; Piper, D.Z.; Murphy, K.; Conard, R.; Pisias, N.

    1984-01-01

    The chemical composition of ferromanganese nodules from the three nodule-bearing MANOP sites in the Pacific can be accounted for in a qualitative way by variable contributions of distinct accretionary processes. These accretionary modes are: 1. (1) hydrogenous, i.e., direct precipitation or accumulation of colloidal metal oxides in seawater, 2. (2) oxic diagenesis which refers to a variety of ferromanganese accretion processes occurring in oxic sediments; and 3. (3) suboxic diagenesis which results from reduction of Mn+4 by oxidation of organic matter in the sediments. Geochemical evidence suggests processes (1) and (2) occur at all three MANOP nodule-bearing sites, and process (3) occurs only at the hemipelagic site, H, which underlies the relatively productive waters of the eastern tropical Pacific. A normative model quantitatively accounts for the variability observed in nearly all elements. Zn and Na, however, are not well explained by the three end-member model, and we suggest that an additional accretionary process results in greater variability in the abundances of these elements. Variable contributions from the three accretionary processes result in distinct top-bottom compositional differences at the three sites. Nodule tops from H are enriched in Ni, Cu, and Zn, instead of the more typical enrichments of these elements in nodule bottoms. In addition, elemental correlations typical of most pelagic nodules are reversed at site H. The three accretionary processes result in distinct mineralogies. Hydrogenous precipitation produces ??MnO2. Oxic diagenesis, however, produces Cu-Ni-rich todorokite, and suboxic diagenesis results in an unstable todorokite which transforms to a 7 A?? phase ("birnessite") upon dehydration. The presence of Cu and Ni as charge-balancing cations influence the stability of the todorokite structure. In the bottoms of H nodules, which accrete dominantly by suboxic diagenesis, Na+ and possibly Mn+2 provide much of the charge balance for

  9. Measurements of the Concentration and Composition of CCN and IN at a High Elevation Site

    NASA Astrophysics Data System (ADS)

    Friedman, B.; Kulkarni, G.; Zelenyuk, A.; Beranek, J.; Pekour, M. S.; Hallar, A. G.; Mccubbin, I. B.; Cziczo, D. J.; Thornton, J. A.

    2011-12-01

    Field measurements of cloud condensation nuclei (CCN) and ice nuclei (IN) were conducted in March 2011 at Storm Peak Laboratory (elevation 3220 m m.s.l.). Measurements of CCN number concentrations and droplet size distributions at supersaturations of 0.05%, 0.1%, 0.2%, 0.4%, and 0.7% were conducted in parallel with Scanning Mobility Particle Sizer (SMPS) measurements of size distributions and number concentrations of ambient particles. SMPS number concentrations of the overall ambient aerosol population were used to calculate the fraction of particles activating as droplets at the supersaturations studied. Single Particle Mass Spectrometer (SPLAT II) was used to characterize number concentration, size, internal composition, and densities of individual particles present in the ambient air. In a separate set of experiments, a pumped counterflow virtual impactor (PCVI) was used to separate particles that activated as CCN from unactivated particles, using a 50% cutsize of approximately 2.5 microns. The droplet residuals from the activated particles were characterized by SPLAT and compared to the properties of the overall aerosol population in order to examine the effect of single particle mixing state, aerosol composition, and size on CCN activity as a function of supersaturation. The PNNL Compact Ice Chamber (CIC) was deployed to measure IN concentrations and ice crystal size distributions at temperatures ranging from 253K to 233K. SMPS number concentrations, size distributions, and SPLAT single particle measurements were also utilized to assess the ice nucleation properties of ambient particles as a function of the processing conditions in the PNNL CIC.

  10. Vertical stratification of subsurface microbial community composition across geological formations at the Hanford Site

    SciTech Connect

    Lin, Xueju; Kennedy, David W.; Fredrickson, Jim K.; Bjornstad, Bruce N.; Konopka, Allan

    2011-11-29

    Microbial diversity in subsurface sediments at the Hanford Site 300 Area near Richland, Washington State (USA) was investigated by analyzing samples recovered from depths of 9 to 52 m. Approximately 8000 near full-length 16S rRNA gene sequences were analyzed across geological strata that include a natural redox transition zone. These strata included the oxic coarse-grained Hanford formation, fine-grained oxic and anoxic Ringold Formation sediments, and the weathered basalt group. We detected 1233 and 120 unique bacterial and archaeal OTUs (Operational Taxonomic Units at the 97% identity level), respectively. Microbial community structure and richness varied substantially across the different geological strata. Bacterial OTU richness (Chao1 estimator) was highest (>700) in the upper Hanford formation, and declined to about 120 at the bottom of the Hanford formation. Just above the Ringold oxic-anoxic interface, richness was about 325 and declined to less than 50 in the deeper reduced zones. The deeper Ringold strata were characterized by a preponderance (ca. 90%) of Proteobacteria. The Bacterial community in the oxic sediments contained not only members of 9 well-recognized phyla but also an unusually high proportion of 3 candidate divisions (GAL15, NC10, and SPAM). Additionally, novel phylogenetic orders were identified within the Delta-proteobacteria, a clade rich in microbes that carry out redox transformations of metals that are important contaminants on the Hanford Site.

  11. Vertical stratification of subsurface microbial community composition across geological formations at the Hanford Site.

    PubMed

    Lin, Xueju; Kennedy, David; Fredrickson, Jim; Bjornstad, Bruce; Konopka, Allan

    2012-02-01

    Microbial diversity in subsurface sediments at the Hanford Site 300 Area near Richland, Washington state (USA) was investigated by analysing 21 samples recovered from depths of 9-52 m. Approximately 8000 near full-length 16S rRNA gene sequences were analysed across geological strata that include a natural redox transition zone. These strata included the oxic coarse-grained Hanford formation, fine-grained oxic and anoxic Ringold Formation sediments, and the weathered basalt group. We detected 1233 and 120 unique bacterial and archaeal OTUs (operational taxonomic units at the 97% identity level) respectively. Microbial community structure and richness varied substantially across the different geological strata. Bacterial OTU richness (Chao1 estimator) was highest (> 700) in the upper Hanford formation, and declined to about 120 at the bottom of the Hanford formation. Just above the Ringold oxic-anoxic interface, richness was about 325 and declined to less than 50 in the deeper reduced zones. The deeper Ringold strata were characterized by a preponderance (c. 90%) of Proteobacteria. The bacterial community in the oxic sediments contained not only members of nine well-recognized phyla but also an unusually high proportion of three candidate divisions (GAL15, NC10 and SPAM). Additionally, 13 novel phylogenetic orders were identified within the Deltaproteobacteria, a clade rich in microbes that carry out redox transformations of metals that are important contaminants on the Hanford Site. PMID:22122741

  12. Composites

    SciTech Connect

    Chou, T.; McCullough, R.L.; Pipes, R.B.

    1986-10-01

    The degree of control over material properties that is typified by hybrid composites is transforming engineering design. In part because homogeneous materials such as metals and alloys do not offer comparable control, specifying a material and designing a component have traditionally taken place separately. As composites begin to replace traditional materials in fields and such as aerospace, component design and the specification of a material are merging and becoming aspects of a single process. The controllable microstructure of a composite allows it to be tailored to match the distribution of stresses to which it will be subject. At the same time components must come to reflect the distinctive nature of composites: their directional properties and the intricate forms they can be given through processes such as injection molding, filament winding and three-dimensional weaving. The complexity inherent in conceiving components and their materials at the same time suggests engineering design will grow increasingly dependent on computers and multidisciplinary teams. Such an approach will harness the full potential of composites for the technologies of the future. 10 figures.

  13. Composite active site of chondroitin lyase ABC accepting both epimers of uronic acid

    SciTech Connect

    Shaya, D.; Hahn, Bum-Soo; Bjerkan, Tonje Marita; Kim, Wan Seok; Park, Nam Young; Sim, Joon-Soo; Kim, Yeong-Shik; Cygler, M.

    2008-03-19

    Enzymes have evolved as catalysts with high degrees of stereospecificity. When both enantiomers are biologically important, enzymes with two different folds usually catalyze reactions with the individual enantiomers. In rare cases a single enzyme can process both enantiomers efficiently, but no molecular basis for such catalysis has been established. The family of bacterial chondroitin lyases ABC comprises such enzymes. They can degrade both chondroitin sulfate (CS) and dermatan sulfate (DS) glycosaminoglycans at the nonreducing end of either glucuronic acid (CS) or its epimer iduronic acid (DS) by a {beta}-elimination mechanism, which commences with the removal of the C-5 proton from the uronic acid. Two other structural folds evolved to perform these reactions in an epimer-specific fashion: ({alpha}/{alpha}){sub 5} for CS (chondroitin lyases AC) and {beta}-helix for DS (chondroitin lyases B); their catalytic mechanisms have been established at the molecular level. The structure of chondroitinase ABC from Proteus vulgaris showed surprising similarity to chondroitinase AC, including the presence of a Tyr-His-Glu-Arg catalytic tetrad, which provided a possible mechanism for CS degradation but not for DS degradation. We determined the structure of a distantly related Bacteroides thetaiotaomicron chondroitinase ABC to identify additional structurally conserved residues potentially involved in catalysis. We found a conserved cluster located {approx}12 {angstrom} from the catalytic tetrad. We demonstrate that a histidine in this cluster is essential for catalysis of DS but not CS. The enzyme utilizes a single substrate-binding site while having two partially overlapping active sites catalyzing the respective reactions. The spatial separation of the two sets of residues suggests a substrate-induced conformational change that brings all catalytically essential residues close together.

  14. Isotopic Composition of Gaseous Elemental Mercury (Hg0) at Various Sites in Japan

    NASA Astrophysics Data System (ADS)

    Yamakawa, A.; Moriya, K.; Yoshinaga, J.

    2015-12-01

    Mercury (Hg) is a toxic heavy metal, which exists in various chemical forms in the environmental system. In the atmosphere, Hg exists in three forms (Hg0(g), Hg+2(g), and Hg(p)). Hg0(g) is the dominant species of atmospheric Hg, accounting for >95% of the total Hg in the atmosphere. Because Hg0(g) is highly volatile and has limited solubility in water, it cannot be easily removed by wet or dry deposition processes. Therefore, the residence time of Hg0(g) in the atmosphere is relatively long (1 to 2 years), allowing long-range transport from mercury emission source(s). Conversely, Hg+2(g) and Hg(p) are effectively removed from the atmosphere through wet and dry depositions. The determination of mercury source attribution using quantitative data is challenging because Hg0(g) may be deposited on an area upon oxidation to Hg+2(g) and associated with aerosols and particulates to form Hg(p) while the global cycling of Hg0(g). Over the last decade, the development of analytical methods of highly precise Hg isotopic measurements demonstrated mass-dependent fractionation (MDF) and mass-independent fractionation (MIF) of Hg isotopes in environmental samples. For instance, MDF of Hg isotopes is thought to occur during various natural and industrial Hg transformations. MIF of Hg isotopes is observed during abiotic reduction, photochemical and non-photochemical, and physical and chemical processes. Such processes lead to differences in the Hg isotopic composition of different emission sources, both natural and anthropogenic, and atmospheric processes (i.e., transportation, oxidation/reduction, deposition, and reemission). Therefore, Hg isotopic compositions could be used to trace the sources and processes of atmospheric Hg. For securing the reliability and accuracy of atmospheric Hg isotope data, the methods of collection, pretreatment, and isotopic measurement for Hg0(g) were developed to obtain high recovery yield of samples with no Hg isotopic fractionation during each

  15. Gas production, composition and emission at a modern disposal site receiving waste with a low-organic content.

    PubMed

    Scheutz, Charlotte; Fredenslund, Anders M; Nedenskov, Jonas; Samuelsson, Jerker; Kjeldsen, Peter

    2011-05-01

    AV Miljø is a modern waste disposal site receiving non-combustible waste with a low-organic content. The objective of the current project was to determine the gas generation, composition, emission, and oxidation in top covers on selected waste cells as well as the total methane (CH(4)) emission from the disposal site. The investigations focused particularly on three waste disposal cells containing shredder waste (cell 1.5.1), mixed industrial waste (cell 2.2.2), and mixed combustible waste (cell 1.3). Laboratory waste incubation experiments as well as gas modeling showed that significant gas generation was occurring in all three cells. Field analysis showed that the gas generated in the cell with mixed combustible waste consisted of mainly CH(4) (70%) and carbon dioxide (CO(2)) (29%) whereas the gas generated within the shredder waste, primarily consisted of CH(4) (27%) and nitrogen (N(2)) (71%), containing no CO(2). The results indicated that the gas composition in the shredder waste was governed by chemical reactions as well as microbial reactions. CH(4) mass balances from three individual waste cells showed that a significant part (between 15% and 67%) of the CH(4) generated in cell 1.3 and 2.2.2 was emitted through leachate collection wells, as a result of the relatively impermeable covers in place at these two cells preventing vertical migration of the gas. At cell 1.5.1, which is un-covered, the CH(4) emission through the leachate system was low due to the high gas permeability of the shredder waste. Instead the gas was emitted through the waste resulting in some hotspot observations on the shredder surface with higher emission rates. The remaining gas that was not emitted through surfaces or the leachate collection system could potentially be oxidized as the measured oxidation capacity exceeded the potential emission rate. The whole CH(4) emission from the disposal site was found to be 820 ± 202 kg CH(4)d(-1). The total emission rate through the leachate

  16. Transient effects on groundwater chemical compositions from pumping of supply wells at the Nevada National Security Site, 1951-2008

    USGS Publications Warehouse

    Paces, James B.; Elliott, Peggy E.; Fenelon, Joseph M.; Laczniak, Randell J.; Moreo, Michael T.

    2012-01-01

    Nuclear testing and support activities at the Nevada National Security Site have required large amounts of water for construction, public consumption, drilling, fire protection, hydraulic and nuclear testing, and dust control. To supply this demand, approximately 20,000 million gallons of water have been pumped from 23 wells completed in 19 boreholes located across the Nevada National Security Site starting as early as the 1950s. As a consequence of more or less continuous pumping from many of these wells for periods as long as 58 years, transient groundwater flow conditions have been created in the aquifers that supplied the water. To evaluate whether long-term pumping caused changes in water compositions over time, available chemical analyses of water samples from these 19 boreholes were compiled, screened, and evaluated for variability including statistically significant temporal trends that can be compared to records of groundwater pumping. Data used in this report have been extracted from a large database (Geochem08, revision 3.0, released in September 2008) containing geochemical and isotopic information created and maintained by primary contractors to the U.S. Department of Energy, National Nuclear Security Administration, Nevada Site Office. Data extracted from this source were compiled for the entire period of record, converted to uniform reporting units, and screened to eliminate analyses of poor or unknown quality, as well as clearly spurious values. The resulting data are included in accompanying spreadsheets that give values for (1) pH and specific conductance, (2) major ion concentrations, (3) trace element concentrations and environmental isotope ratios, and (4) mean, median, and variance estimates for major ion concentrations. The resulting data vary widely in quality and time-series density. An effort has been made to establish reasonable ranges of analytical uncertainty expected for each analyte and eliminate analyses that are obvious outliers

  17. Numerical studies of gas composition differentiation during gas hydrate formation: An application to the IODP site 1327

    NASA Astrophysics Data System (ADS)

    Yuncheng, C.; Chen, D.

    2014-12-01

    Structure I methane hydrate is the most common type found in nature. Structure I gas hydrate has two types of cages that gas molecules may be hosted. Because the larger cavities filled with ethane would be more stable than those filled by methane (Sloan and Koh, 2008), the larger cavities preferentially enclose ethane during the formation of gas hydrate, which results gas composition differentiation during gas hydrate formation. Based on the principle of gas composition differentiation, we establish a numerical model for the gas composition differentiation between methane and ethane during gas hydrate accumulation and applied the model to IODP site 1327. The simulation shows that the gas composition differentiation only occurs at the interval where gas hydrate presents. The lowest methane/ethane (C1/C2) point indicates the bottom of hydrate zone, and the composition differentiation produces the upward increase of C1/C2 within the gas hydrate zone. The C1/C2 reaches the largest value at the top occurrence of gas hydrate and keeps relative stable above the top occurrence of gas hydrate. The top and bottom occurrence of gas hydrate indicated by the inflection points of the C1/C2 profile are similar to those indicated by the negative anomalies of measured chloride concentrations (Riedel et al., 2006). By comparing with the measured C1/C2, the differentiation coefficient (kh=Xe,h/Xe,w, Xe,h is C1/C2 of the formed gas hydrate, Xe,w [mol/kg] is the concentration of ethane in water ) is calculated to 70 kg/mol. The top occurrence of gas hydrate indicated by the C1/C2 profile also confines the water flux to be 0.4kg/m2-year, similar to that confined by the chloride profile. To best fit the measured C1/C2 profile, the methane flux is calculated to 0.04mol/m2-year. Therefore, the C1/C2 profile could be used to obtain the gas hydrate accumulation information. Acknowledgments:This study was supported by Chinese National Science Foundation (grant 41303044, 91228206 ) References

  18. Analysis of High Frequency Site-Specific Nitrogen and Oxygen Isotopic Composition of Atmospheric Nitrous Oxide at Mace Head, Ireland

    NASA Astrophysics Data System (ADS)

    McClellan, M. J.; Harris, E. J.; Olszewski, W.; Ono, S.; Prinn, R. G.

    2014-12-01

    Atmospheric nitrous oxide (N2O) significantly impacts Earth's climate due to its dual role as an inert potent greenhouse gas in the troposphere and as a reactive source of ozone-destroying nitrogen oxides in the stratosphere. However, there remain significant uncertainties in the global budget of this gas. The marked spatial divide in its reactivity means that all stages in the N2O life cycle—emission, transport, and destruction—must be examined to understand the overall effect of N2O on climate. Source and sink processes of N2O lead to varying concentrations of N2O isotopologues (14N14N16O, 14N15N16O, 15N14N16O, and 14N14N18O being measured) due to preferential isotopic production and elimination in different environments. Estimation of source and sink fluxes can be improved by combining isotopically resolved N2O observations with simulations using a chemical transport model with reanalysis meteorology and treatments of isotopic signatures of specific surface sources and stratospheric intrusions. We present the first few months of site-specific nitrogen and oxygen isotopic composition data from the Stheno-TILDAS instrument (Harris et al, 2013) at Mace Head, Ireland and compare these to results from MOZART-4 (Model for Ozone and Related Chemical Tracers, version 4) chemical transport model runs including N2O isotopic fractionation processes and reanalysis meterological fields (NCEP/NCAR, MERRA, and GEOS-5). This study forms the basis for future inverse modeling experiments that will improve the accuracy of isotopically differentiated N2O emission and loss estimates. Ref: Harris, E., D. Nelson, W. Olszewski, M. Zahniser, K. Potter, B. McManus, A. Whitehill, R. Prinn, and S. Ono, Development of a spectroscopic technique for continuous online monitoring of oxygen and site-specific nitrogen isotopic composition of atmospheric nitrous oxide, Analytical Chemistry, 2013; DOI: 10.1021/ac403606u.

  19. Chemical compositions of wet precipitation and anthropogenic influences at a developing urban site in southeastern China

    NASA Astrophysics Data System (ADS)

    Zhang, Miaoyun; Wang, Shijie; Wu, Fengchang; Yuan, Xianghong; Zhang, Ying

    2007-06-01

    A comprehensive study on the chemical compositions of wet precipitation was carried out from January 2004 to December 2004 in Jinhua, southeastern China's Zhejiang Province. All samples were analyzed for pH, electrical conductivity and major ions (F -, Cl -, NO 3-, SO 42-, K +, Na +, Ca 2+, Mg 2+ and NH 4+). The rainwater was typically acidic with a volume-weighted mean pH of 4.54, which ranged from 3.64 to 6.76. SO 42- and NO 3- were the main anions, while NH 4+ and Ca 2+ were the main cations. The concentrations of these major ions were generally higher compared to those reported in other parts of the world, but much lower than those in northern China. Wet deposition fluxes of major ions showed pronounced seasonal variations with maximum in spring and minimum in autumn. Significant correlations were found in soil-derived species among Ca 2+, Mg 2+ and K + and sea-salt species between Na + and Cl -. Other relatively good correlations were also observed between Ca 2+ and SO 42-, Mg 2+ and SO 42-, Mg 2+ and NO 3-, Mg 2+ and Cl -. Principal component analysis was also performed on individual precipitation to find possible sources of the major ionic species. Varimax rotated four components accounting for 85.9% of the total variance, and were interpreted as acid and alkaline pollutants, sea spray and mixed source, soil and acid/neutralization. Calculation of enrichment factors for rainwater components relative to soil and seawater indicated that Ca 2+ and K + mainly originated from the terrestrial source, and SO 42- and NO 3- were mostly attributed for the anthropogenic activities in the study area. In general, the results suggested that precipitation chemistry is strongly influenced by anthropogenic sources rather than natural and marine sources. The pollutants in rainwater were mainly derived from long distance transport, local industry and traffic sources.

  20. Benson Beach Demonstration Project: Composition and Abundance of Biota at Three Alternative Sump Sites

    SciTech Connect

    Williams, Greg D.; Pearson, Walter H.; Evans, Nathan R.; Anderson, Michael G.

    2004-01-15

    The Portland District of the U.S. Army Corps of Engineers is investigating plans to provide sediment to nourish beaches north of the Mouth of the Columbia River (MCR). Under the currently designed proposal, sediment dredged from the MCR will be temporarily stored at one of three proposed areas south of the North Jetty before being redredged and moved by a cutterhead pipeline dredge over the jetty to nourish Benson Beach. Resulting potential impacts to resident Dungeness crab (Cancer magister) and fishes represent one of the criteria for evaluating each of the alternative locations. To establish the species composition and relative abundance of crabs and fishes associated with each of the three proposed sump areas, researchers from the Pacific Northwest National Laboratory Marine Sciences Division completed nine field sampling trips from July 8, 2003, to November 1, 2003, for a total of 113 successful trawls comprising an area of over 7.4 ha (74,156 m2). This report documents the results of that effort. To understand the relative risk of losses to crab populations associated with dredging impacts at the sump alternative areas, it is recommended that a modified dredge impact model be developed using the data collected in this study. This model should estimate crab adult equivalent loss and associated error rates to gain a population-level perspective on the potential entrainment impacts at each of the three alternative sump areas. As well, a sustained survey of Dungeness crab distribution and movement within the Columbia River estuary would clarify the relative value of the sump areas as a migratory corridor for crab populations, and support management decisions relative to issues associated with dredged material handling and disposal.

  1. Composition and stability of the condensate observed at the Viking Lander 2 site on Mars

    NASA Technical Reports Server (NTRS)

    Hart, H. M.; Jakosky, B. M.

    1986-01-01

    Surface energy balance and near-surface temperature data from the Viking Lander 2 site taken during the first winter that condensated were observed and analyzed to determine the relative stability of CO2 and H2O frosts. The CO2 frost stability is calculated with an equilibrium surface energy balance model, i.e., the total energy incident on a frost surface is compared with the blackbody energy emitted by the surface. The energy sources considered were IR emission from the atmosphere, sunlight, and the sensible heat flux from the atmosphere. H2O stability was examined as a function of buoyant diffusion and turbulent mixing processes which could remove saturated near-surface gases. The CO2 frost is found to be sufficiently unstable at the time the condensate was observed on the ground, so all CO2 ice deposited at night would boil away in a few hours of sunlight. CO2 ice would not form during a dust storm. Water frost would be stable during the condensate observations, since sublimation would occur at a rate below 1 micron/day. A stable winter thickness of 10 microns is projected for the water ice.

  2. Muscle fibre types in the human vastus lateralis muscles: do symmetrical sites differ in their composition?

    PubMed

    Erzen, I; Pernus, F; Sirca, A

    1990-01-01

    Muscle samples obtained from distinct symmetrical sites of left and right vastus lateralis muscles from 10 young healthy males were analysed. A computer-aided system was applied for the determination of muscle fibre types I, IIA, IIB and IIC and for their quantitative analysis. No statistically significant differences were established regarding percentage and surface area of all the four fibre types studied. In 2 cases of IIA and in one case of IIB fibre type significantly different diameters were measured between the left and right muscle. Regarding percentage and surface area no differences were proved between superficial and deep layers of the muscles observed. Fibre diameter but differed significantly in many muscles, there was no rule about whether it was larger in superficial or in deep muscle layers. One biopsy sample can not represent the whole muscle, especially as far as the relative number and surface area of the type IIA and IIB fibres are concerned. A slight asymmetry in fibre diameters of biopsy samples from both legs does not indicate any pathological change and can still be taken for normal. PMID:2403213

  3. Studying the effect of the Semipalatinsk Test Site on radionuclide and elemental composition of water objects in the Irtysh River.

    PubMed

    Solodukhin, V; Аidarkhanov, A; Lukashenko, S; Gluchshenko, V; Poznyak, V; Lyahova, O

    2015-06-01

    The results of the field and laboratory studies of radiation and environmental state at the specific area of Irtysh River adjacent to the Semipalatinsk Test Site are provided. It was found that the radiation situation in this area is normal: equivalent dose of γ-radiation = (0.11-0.13) µSv h(-1). Determination of radionuclide composition of soil, bottom sediment and water samples was performed by the methods of instrumental γ-spectrometry, radiochemical analysis and the liquid scintillation β-spectrometry. It was found that concentrations of the studied natural and artificial radionuclides in these objects are very low; no contamination with radionuclides was detected in this segment of Irtysh River. The article provides the results of elemental composition determination for samples of soil and bottom sediment (by X-ray fluorescence method) and water samples (by inductively coupled plasma mass spectrometry method). It is shown that the content of some elements (Li, Be, B, V, Cu, Sr, Mo) in the water of Irtysh River increases downstream. The additional studies are required to explain this peculiarity. PMID:25971345

  4. Vertical stratification of subsurface microbial community composition across geological formations at the Hanford Site

    SciTech Connect

    Lin, Xueju; Kennedy, David W.; Fredrickson, Jim K.; Bjornstad, Bruce N.; Konopka, Allan

    2012-02-01

    The microbial diversity in subsurface sediments at the Hanford Site's 300 Area in southeastern Washington State was investigated by analyzing 21 samples recovered from depths that ranged from 9 to 52 m. Approximately 8000 non-chimeric Bacterial and Archaeal 16S rRNA gene sequences were analyzed across geological strata that contain a natural redox transition zone. These strata included the oxic coarse-grained Hanford formation, fine-grained oxic and anoxic Ringold Formation sediments, and the weathered basalt group. We detected 1233 and 120 unique bacterial and archaeal OTUs (Operational Taxonomic Units, defined at the 97% identity level). Microbial community structure and richness varied substantially across the different geological strata. Bacterial OTU richness (based upon Chao1 estimator) was highest (>700) in the upper Hanford formation, and declined to about 120 at the bottom of the Hanford formation. Just above the Ringold oxic-anoxic transition zone, richness was about 325 and declined to less than 50 in the deeper reduced zones. The Bacterial community in the oxic Hanford and Ringold Formations contained members of 9 major well-recognized phyla as well 30 as unusually high proportions of 3 candidate divisions (GAL15, NC10, and SPAM). The deeper Ringold strata were characterized by low OTU richness and a very high preponderance (ca. 90%) of Proteobacteria. The study has greatly expanded the intralineage phylogenetic diversity within some major divisions. These subsurface sediments have been shown to contain a large number of phylogenetically novel microbes, with substantial heterogeneities between sediment samples from the same geological formation.

  5. The fat-fascia paddle only with a composite fibula flap: marked reduction in donor site morbidity.

    PubMed

    Mohindra, A; Parmar, S; Praveen, P; Martin, T

    2016-08-01

    Fibula free flaps are used widely in head and neck reconstruction, primarily for their versatility and contribution to aesthetic and functional outcomes. The literature suggests that early complications such as wound dehiscence and skin graft loss can occur in up to a third of patients. The healing of these donor sites can be prolonged, and in certain cases may require an operative intervention. A method to overcome this problem is described herein. In raising the skin paddle, a standard lateral approach to the fibula harvest is used. The skin paddle is not isolated and the posterior margin of the paddle is maintained. The skin paddle epithelium is separated with a small cuff of adipose tissue from the underlying fat-fascia layer. This fat-fascia paddle is then raised with the fibula as normal and tacked to the margins of the recipient soft tissue defect. The fat-fascia paddle heals, resulting in a thin mucosal covering for prosthetic dental rehabilitation. This technique can reduce the incidence of donor site wound complications when raising a composite fibula flap. PMID:27061479

  6. COMPOSITE ANALYSIS OF LLW DISPOSAL FACILITIES AT THE U.S. DEPARTMENT OF ENERGY'S SAVANNAH RIVER SITE

    SciTech Connect

    Hiergesell, R; Mark Phifer, M; Frank02 Smith, F

    2009-01-08

    Composite Analyses (CA's) are required per DOE Order 435.1 [1], in order to provide a reasonable expectation that DOE low-level waste (LLW) disposal, high-level waste tank closure, and transuranic (TRU) waste disposal in combination with Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), Resource Conservation and Recovery Act (RCRA), and deactivation and decommissioning (D&D) actions, will not result in the need for future remedial actions in order to ensure radiological protection of the public and environment. This Order requires that an accounting of all sources of DOE man-made radionuclides and DOE enhanced natural radionuclides that are projected to remain on the site after all DOE site operations have ceased. This CA updates the previous CA that was developed in 1997. As part of this CA, an inventory of expected radionuclide residuals was conducted, exposure pathways were screened and a model was developed such that a dose to the MOP at the selected points of exposure might be evaluated.

  7. Composites

    NASA Astrophysics Data System (ADS)

    Taylor, John G.

    The Composites market is arguably the most challenging and profitable market for phenolic resins aside from electronics. The variety of products and processes encountered creates the challenges, and the demand for high performance in critical operations brings value. Phenolic composite materials are rendered into a wide range of components to supply a diverse and fragmented commercial base that includes customers in aerospace (Space Shuttle), aircraft (interiors and brakes), mass transit (interiors), defense (blast protection), marine, mine ducting, off-shore (ducts and grating) and infrastructure (architectural) to name a few. For example, phenolic resin is a critical adhesive in the manufacture of honeycomb sandwich panels. Various solvent and water based resins are described along with resin characteristics and the role of metal ions for enhanced thermal stability of the resin used to coat the honeycomb. Featured new developments include pultrusion of phenolic grating, success in RTM/VARTM fabricated parts, new ballistic developments for military vehicles and high char yield carbon-carbon composites along with many others. Additionally, global regional market resin volumes and sales are presented and compared with other thermosetting resin systems.

  8. A functional glucocorticoid-responsive unit composed of two overlapping inactive receptor-binding sites: evidence for formation of a receptor tetramer.

    PubMed Central

    Garlatti, M; Daheshia, M; Slater, E; Bouguet, J; Hanoune, J; Beato, M; Barouki, R

    1994-01-01

    An unusual glucocorticoid-responsive element (called GRE A) was found to mediate the induction of the cytosolic aspartate aminotransferase gene by glucocorticoids and was bound by the glucocorticoid receptor in a DNase I footprinting assay. GRE A consists of two overlapping GREs, each comprising a conserved half-site and an imperfect half-site. The complete unit was able to confer glucocorticoid inducibility to a heterologous promoter (delta MTV-CAT). Mutation of any of the half-sites, including the imperfect ones, abolished inducibility by the hormone, demonstrating that each of the isolated GREs was inactive. In electrophoretic mobility shift assays, purified rat liver glucocorticoid receptor (GR) formed a low-mobility complex with GRE A, presumably containing a GR tetramer. When purified bacterially expressed DBD was used, low-mobility complexes as well as dimer and monomer complexes were formed. In inactive mutated oligonucleotides, no GR tetramer formation was detected. Modification of the imperfect half-sites in order to increase their affinity for GR gave a DNA sequence that bound a GR tetramer in a highly cooperative manner. This activated unit consisting of two overlapping consensus GREs mediated glucocorticoid induction with a higher efficiency than consensus GRE. Images PMID:7969140

  9. sup 1 H NMR studies of DNA recognition by the glucocorticoid receptor: Complex of the DNA binding domain with a half-site response element

    SciTech Connect

    Remerowski, M.L.; Kellenbach, E.; Boelens, R.; Kaptein, R. ); van der Marel, G.A.; van Boom, J.H. ); Maler, B.A.; Yamamoto, K.R. )

    1991-12-17

    The complex of the rat glucocorticoid receptor (GR) DNA binding domain (DBD) and half-site sequence of the consensus glucocorticoid response element (GRE) has been studied by two-dimensional {sup 1}H NMR spectroscopy. The DNA fragment is a 10 base-pair oligonucleotide, 5{prime}d(GCTGTTCTGC)3{prime}{center dot}5{prime}d-(GCAGAACAGC)3{prime}, containing the stronger binding GRE half-site hexamer, with GC base pairs at each end. The 93-residue GR-DBD contains an 86-residue segment corresponding to residues 440-525 of the rat GR. Eleven NOE cross peaks between the protein and DNA have been identified, and changes in the chemical shift of the DNA protons upon complex formation have been analyzed. Using these protein-DNA contact points, it can be concluded that (1) the 'recognition helix' formed by residues C460-E469 lies in the major groove of the DNA; (2) the GR-DBD is oriented on the GRE half-site such that residues A477-D481, forming the so-called D-loop, are available for protein-protein interaction in the GR-DBD dimer on the intact consensus GRE; and (3) the 5-methyl of the second thymine in the half-site and valine 462 interact, confirming indirect evidence that both play an important role in GR-DBD DNA binding.

  10. Composition and sources of fine particulate matter across urban and rural sites in the Midwestern United States

    PubMed Central

    Kundu, Shuvashish; Stone, Elizabeth. A.

    2014-01-01

    The composition and sources of fine particulate matter (PM2.5) were investigated in rural and urban locations in Iowa, located in the agricultural and industrial Midwestern United States from April 2009 to December 2012. Major chemical contributors to PM2.5 mass were sulfate, nitrate, ammonium, and organic carbon. Non-parametric statistical analyses demonstrated that the two rural sites had significantly enhanced levels of crustal materials (Si, Al) driven by agricultural activities and unpaved roads. Meanwhile, the three urban areas had enhanced levels of secondary aerosol (nitrate, sulfate, and ammonium) and combustion (organic and elemental carbon). The heavily industrialized Davenport site had significantly higher levels of PM2.5 and trace metals (Fe, Pb, Zn), demonstrating the important local impact of industrial point sources on air quality. Sources of PM2.5 were evaluated by the multi-variant positive matrix factorization (PMF) source apportionment model. For each individual site, seven to nine factors were identified: secondary sulfate (accounting for 29–30% of PM2.5), secondary nitrate (17–24%), biomass burning (9–21%), gasoline combustion (6–16), diesel combustion (3–9%), dust (6–11%), industry (0.4–5%) and winter salt (2–6%). Source contributions demonstrated a clear urban enhancement in PM2.5 from gasoline engines (by a factor of 1.14) and diesel engines (by a factor of 2.3), which is significant due to the well-documented negative health impacts of vehicular emissions. This study presents the first source apportionment results from the state of Iowa and is broadly applicable to understanding the differences in anthropogenic and natural sources in the urban-rural continuum of particle air pollution. PMID:24736797

  11. Composites

    NASA Astrophysics Data System (ADS)

    Chmielewski, M.; Nosewicz, S.; Pietrzak, K.; Rojek, J.; Strojny-Nędza, A.; Mackiewicz, S.; Dutkiewicz, J.

    2014-11-01

    It is commonly known that the properties of sintered materials are strongly related to technological conditions of the densification process. This paper shows the sintering behavior of a NiAl-Al2O3 composite, and its individual components sintered separately. Each kind of material was processed via the powder metallurgy route (hot pressing). The progress of sintering at different stages of the process was tested. Changes in the microstructure were examined using scanning and transmission electron microscopy. Metal-ceramics interface was clean and no additional phases were detected. Correlation between the microstructure, density, and mechanical properties of the sintered materials was analyzed. The values of elastic constants of NiAl/Al2O3 were close to intermetallic ones due to the volume content of the NiAl phase particularly at low densities, where small alumina particles had no impact on the composite's stiffness. The influence of the external pressure of 30 MPa seemed crucial for obtaining satisfactory stiffness for three kinds of the studied materials which were characterized by a high dense microstructure with a low number of isolated spherical pores.

  12. Biomarker Compositions as Source Indicators of Heinrich Layers in the Northern North Atlantic (IODP Exp. 303/306, Site 1305)

    NASA Astrophysics Data System (ADS)

    Hefter, J.; Stein, R.

    2006-12-01

    During IODP Expeditions 303/306, multiple cores from different locations in the North Atlantic were recovered. One of the major objectives of these expeditions was to capture Miocene-Quaternary millenial-scale climate variability in sensitive regions at the mouth of the Labrador Sea and in the North Atlantic ice-rafted debris (IRD) belt. Site 1305 is located in the Labrador Sea close to the southwest extremity of the Eirik Drift and in proximity to the former major iceberg discharge pathway derived via the Hudson Strait from the Laurentide-Ice- Shield (LIS). The upper Pleistocene part of Site 1305 afforded discrete IRD-containing detrital carbonate sections known as Heinrich layers (HL). About 30 samples from within and in between these layers were investigated in terms of quantitative and qualitative biomarker distribution using gas chromatography-mass spectrometry to (a) extend previous knowledge of biomarker inventories from identified Heinrich layers and (b) to investigate the potential of specific compounds to trace the occurrence and first appearance of Heinrich event-like episodes. Samples from HL1, HL2 and HL4 at Site 1305 are clearly distinguishable from samples between those layers due to the abundance of characteristic biomarker groups such as benzohopanes, D-ring monoaromatic 8,14- secohopanes, mono- and triaromatic steranes, aryl isoprenoids including isorenieratene-derivatives and increased pristane/n-C17 and phytane/n-C18 ratios. Such biomarker compositions are typically observed as diagenetic products within different types of mature (including Palaeozoic) source rocks and oils found in different North American/Canadian Basins, but cannot derive from sources contemporary to the time when Heinrich events occurred. More likely, these compounds originate from LIS basal erosion of Palaeozoic sedimentary outcrops, subsequently transported as IRD through the Hudson Strait and released at Site 1305 during Heinrich events. Thus, the study of specific

  13. Chemical composition and mass size distribution of PM1.0 at an elevated site in central east China

    NASA Astrophysics Data System (ADS)

    Zhang, Y. M.; Zhang, X. Y.; Sun, J. Y.; Hu, G. Y.; Shen, X. J.; Wang, Y. Q.; Wang, T. T.; Wang, D. Z.; Zhao, Y.

    2014-06-01

    Size-resolved aerosol chemical compositions were measured continuously for one and half years with an aerosol mass spectrometer (AMS) to characterize the mass and size distributions (MSDs) of each component in bulk, fresh and aged submicron particles (approximately PM1.0) at Mountain Tai, an elevated site in Central East China (CEC) from June 2010 to January 2012. The majority of the regionally-dispersed aerosols were found to be contributed from short distance mixed aerosol, mostly from its south with organics and sulfate as the major components. The annual mean mass concentrations of organics, sulfate, nitrate, ammonium and chloride were 11.2, 9.2, 7.2, 5.8 and 0.95 μg m-3, respectively, which are much lower for organics and sulfate, and slightly lower for nitrate, ammonium and chloride than those at the nearby surface rural sites. High organics were observed for all four seasons, and the relatively fresh organic aerosol (OA) containing high proportion of less-photo chemically OA, were found from long-range transported aerosol from northwest. Semi-volatile and low-volatile oxidized OAs together contributed approximately 49%, 55% in spring and 72% and 51% in winter of total OA, showing at least 50% of OA can be attributable to SOA. Seasonally, the chemical components at the elevated site showed a "winter high and autumn low" pattern, with organics, sulfate and ammonium peaking in summer. Though no obvious differences of MSDs were seen for various chemical components in the planetary boundary layer (PBL) and free troposphere (FT), the concentrations were a factor of 5-7 higher in PBL than in FT. The averaged MSDs of particles between 30-1000 nm for organics, sulfate, nitrate, and ammonium are approximately log-normal with similar mass median diameters (MMDs) of 539, 585, 542, and 545 nm, respectively, which were slightly larger than those in ground sites within North China Plain (NCP). Obvious differences in MMDs were found between fresh and aged aerosols for

  14. An Examination of the Link between Rater Calibration Performance and Subsequent Scoring Accuracy in Graduate Record Examinations[R] (GRE[R]) Writing. Research Report. ETS RR-11-03

    ERIC Educational Resources Information Center

    Ricker-Pedley, Kathryn L.

    2011-01-01

    A pseudo-experimental study was conducted to examine the link between rater accuracy calibration performances and subsequent accuracy during operational scoring. The study asked 45 raters to score a 75-response calibration set and then a 100-response (operational) set of responses from a retired Graduate Record Examinations[R] (GRE[R]) writing…

  15. Characterisation of the organic composition of size segregated atmospheric particulate matter at traffic exposed and background sites in Madrid

    NASA Astrophysics Data System (ADS)

    Mirante, F.; Perez, R.; Alves, C.; Revuelta, M.; Pio, C.; Artiñano, B.; Nunes, T.

    2010-05-01

    The growing awareness of the impact of atmospheric particulate matter (PM) on climate, and the incompletely recognised but serious effects of anthropogenic aerosols on air quality and human health, have led to diverse studies involving almost exclusively the coarse or the fine PM fractions. However, these environmental effects, the PM formation processes and the source assignment depend greatly on the particle size distribution. The innovative character of this study consists in obtaining time series with a size-segregated detailed chemical composition of PM for differently polluted sites. In this perspective, a summer sampling campaign was carried out from 1 of June to 1 of July 2009. One of the sampling sites was located at a representative urban monitoring station (Escuelas Aguirre) belonging to the municipal network, located at a heavy traffic street intersection in downtown Madrid. Other sampling point was positioned within the CIEMAT area, located in the NW corner of the city, which can be considered an urban background or suburban site. Particulate matter was sampled with high volume cascade impactors at 4 size stages: 10-2.5, 2.5-0.95, 0.95-0.45 and < 0.45 µm. Daily sampling was carried out on quartz fibre filters. Based on meteorological conditions and PM mass concentrations, each one of the 7 groups of filters collected during the first week were combined with the corresponding filters of the third week. The same procedure was undertaken with samples of the second and fourth weeks. Filters of 0.95-0.45 and < 0.45 µm were pooled to obtain the PM0.95 organic composition. The PM size-segregated samples were subjected to organic analysis by gas chromatography-mass spectrometry (GC-MS), after solvent extraction of filters and an appropriate derivatisation technique. Besides the homologous compound series of organic classes (e.g. n-alkanes, n-alkanols and n-alkanoic acids), special attention was given to the determination of specific molecular markers for

  16. Gas production, composition and emission at a modern disposal site receiving waste with a low-organic content

    SciTech Connect

    Scheutz, Charlotte; Fredenslund, Anders M.; Nedenskov, Jonas; Samuelsson, Jerker

    2011-05-15

    AV Miljo is a modern waste disposal site receiving non-combustible waste with a low-organic content. The objective of the current project was to determine the gas generation, composition, emission, and oxidation in top covers on selected waste cells as well as the total methane (CH{sub 4}) emission from the disposal site. The investigations focused particularly on three waste disposal cells containing shredder waste (cell 1.5.1), mixed industrial waste (cell 2.2.2), and mixed combustible waste (cell 1.3). Laboratory waste incubation experiments as well as gas modeling showed that significant gas generation was occurring in all three cells. Field analysis showed that the gas generated in the cell with mixed combustible waste consisted of mainly CH{sub 4} (70%) and carbon dioxide (CO{sub 2}) (29%) whereas the gas generated within the shredder waste, primarily consisted of CH{sub 4} (27%) and nitrogen (N{sub 2}) (71%), containing no CO{sub 2}. The results indicated that the gas composition in the shredder waste was governed by chemical reactions as well as microbial reactions. CH{sub 4} mass balances from three individual waste cells showed that a significant part (between 15% and 67%) of the CH{sub 4} generated in cell 1.3 and 2.2.2 was emitted through leachate collection wells, as a result of the relatively impermeable covers in place at these two cells preventing vertical migration of the gas. At cell 1.5.1, which is un-covered, the CH{sub 4} emission through the leachate system was low due to the high gas permeability of the shredder waste. Instead the gas was emitted through the waste resulting in some hotspot observations on the shredder surface with higher emission rates. The remaining gas that was not emitted through surfaces or the leachate collection system could potentially be oxidized as the measured oxidation capacity exceeded the potential emission rate. The whole CH{sub 4} emission from the disposal site was found to be 820 {+-} 202 kg CH{sub 4} d

  17. Stable Carbon and Oxygen Isotope Composition of Soil and Shell from an Archeological Site in Kimble County, Texas

    NASA Astrophysics Data System (ADS)

    Salazar, K. K.; Paul, D.; Skrzypek, G.; Tomka, S. A.

    2007-12-01

    We report stable carbon (δ13C) and oxygen (δ18O) isotopic composition of inorganic carbonates, soil organic matter (SOM), and terrestrial gastropod shells present in a 130cm soil profile (radiocarbon date of 2340-2120 B.P) recovered from archeological site 41KM69, Kimble County, Texas. Prior to soil carbonate and SOM analyses, samples were treated with 5% sodium hypochlorite to remove organic matter and treated with 4% HCl to remove inorganic carbonate, respectively. Isotopic compositions of samples were obtained utilizing a Gasbench II (for carbonate-acid reaction technique) and a CHNS Elemental Analyzer (for SOM) coupled with a DeltaPlus XP Isotope Ratio Mass Spectrometer in continuous-flow. δ13C of carbonates in the soil profile varies in the range -2.15 to -4.63 ‰. δ18O of carbonates (ranging from -3.22 to -3.92‰) show little variation within the profile. δ13C of SOM (-25.61‰ to -22.83‰) suggests that C3 plants were predominant in the study area. There is ~3‰ enrichment in 13C of SOM at the bottom of profile relative to the top. Previous studies have shown that δ13C of modern soil carbonates are higher by 14-16‰ than SOM, whereas our results show about 20‰ difference. δ13C of land snail shells ( Rabdotus, Polygyra, Helicina) recovered from the soil show strong linear correlation with depth (R2= 0.88): -9.46‰ at 60cm to -5.4‰ at 112cm. δ18O of shells show no correlation with depth and range from - 3.34‰ to 0.62‰. Excluding one shell analysis, δ13C of shells and SOM exhibit good correlation (R2= 0.80). Previous studies of variation in δ13C in land snail shell document that carbon isotopic composition in shell are primarily a function of snail diet. Balakrishnan et al. (2005) have shown that δ13C of shells in C3 vegetation regimes range from -10.0‰ to -8.8‰, which is consistent with our results. Although, the interpretation of δ18O values in land snails is not straightforward, values are probably related to several different

  18. Osmotically regulated floating asymmetric membrane capsule for controlled site-specific delivery of ranitidine hydrochloride: optimization by central composite design.

    PubMed

    Chauhan, Manvendra S; Kumar, Anil; Pathak, Kamla

    2012-12-01

    A nondisintegrating, floating asymmetric membrane capsule (FAMC) was developed to achieve site-specific osmotic flow of a highly water-soluble drug, ranitidine hydrochloride (RHCl), in a controlled manner. Solubility suppression of RHCl was achieved by the common ion effect, using optimized coated sodium chloride as a formulation component. The capsular wall of FAMC was prepared by the phase inversion process wherein the polymeric membrane was precipitated on glass pins by dipping them in a solution of cellulose acetate followed by quenching. Central composite design was utilized to investigate the influence of independent variables, namely, level(s) of membrane former, pore former, and osmogen, on percent cumulative drug release (response). The release mechanism of RHCl through FAMC was confirmed as osmotic pumping. The asymmetry of the membrane was characterized by scanning electron microscopy that revealed a dense nonporous outer region of membrane supported by an inner porous region. Differential scanning calorimetry indicated no incompatibility between the drug and excipients. In vitro drug release in three biorelevant media, pH 2.5 (low fed), pH 4.5 (intermediate fed), and pH 6.5 (high fed), demonstrated pH-independent release of RHCl (P > 0.05). Floating ability for 12 h of the optimized FAMC9 was visually examined during the in vitro release studies that showed maximal drug release with zero-order kinetics (r (2) = 0.9991). Thus, a novel osmotically regulated floating capsular system was developed for site-specific delivery of RHCl. PMID:23104305

  19. Fine and coarse PM composition and sources in rural and urban sites in Switzerland: local or regional pollution?

    PubMed

    Minguillón, M C; Querol, X; Baltensperger, U; Prévôt, A S H

    2012-06-15

    The chemical composition and sources of ambient particulate matter (PM) in Switzerland were studied. PM(1) and PM(10) samples were collected in winter and summer at an urban background site in Zurich and a rural background site in Payerne. Concentrations of major and trace elements, NO(3)(-), SO(4)(2-), NH(4)(+), organic and elemental carbon were determined. A subsequent Positive Matrix Factorization (PMF) analysis was performed. PM(10) and PM(1) concentrations varied similarly at both sites, with average PM(10) concentrations 24-25 μg/m(3) and 13-14 μg/m(3) in winter and summer, respectively, and average PM(1) concentrations 12-17 μg/m(3) and 6-7 μg/m(3). The influence of local sources was found to be higher in winter. PM was dominated by nitrate and organic matter in winter, and by mineral matter and organic matter in summer. Trace element concentrations related to road traffic (Zn, Cu, Sb, Sn) were higher at Zurich. Concentrations of Tl and Cs, attributed to the influence of a glass industry, were higher at Payerne. The elements mainly present in the coarse fraction were those related to mineral matter and brake and tyre abrasion (Cu, Mn, Ti, Sb, Sr, Bi, Li, La, Nd), and those in the fine fraction were related to high temperature anthropogenic processes (Pb, As, Cd, Tl, Cs). Common PM(1) and PM(1-10) sources identified by PMF were: ammonium nitrate, present in winter, negligible in summer; ammonium sulfate+K(biomass burning)+road traffic; and road traffic itself, related to exhaust emissions in PM(1) and to road dust resuspension in PM(1-10). Size-fraction specific sources were: a PM(1) glass industry source characterized by Cs, Tl, Rb, Li and Na, only present in Payerne; a PM(1) background source characterized by V, Ni, sulfate and Fe; two PM(1-10) mineral-related sources, with higher contribution in summer; a PM(1-10) salt source; and a PM(1-10) organic source, with higher contribution in summer, attributed to bioaerosols. PMID:22572211

  20. Evaluation of the Community Multiscale Air Quality (CMAQ) modeling system against size-resolved measurements of inorganic particle composition across sites in North America

    EPA Science Inventory

    This work evaluates particle size-composition distributions simulated by the Community Multiscale Air Quality (CMAQ) model using Micro-Orifice Uniform Deposit Impactor (MOUDI) measurements at 18 sites across North America. Size-resolved measurements of particulate SO4<...

  1. Organic composition of size segregated atmospheric particulate matter, during summer and winter sampling campaigns at representative sites in Madrid, Spain

    NASA Astrophysics Data System (ADS)

    Mirante, Fátima; Alves, Célia; Pio, Casimiro; Pindado, Oscar; Perez, Rosa; Revuelta, M.a. Aranzazu; Artiñano, Begoña

    2013-10-01

    Madrid, the largest city of Spain, has some and unique air pollution problems, such as emissions from residential coal burning, a huge vehicle fleet and frequent African dust outbreaks, along with the lack of industrial emissions. The chemical composition of particulate matter (PM) was studied during summer and winter sampling campaigns, conducted in order to obtain size-segregated information at two different urban sites (roadside and urban background). PM was sampled with high volume cascade impactors, with 4 stages: 10-2.5, 2.5-1, 1-0.5 and < 0.5 μm. Samples were solvent extracted and organic compounds were identified and quantified by GC-MS. Alkanes, polycyclic aromatic hydrocarbons (PAHs), alcohols and fatty acids were chromatographically resolved. The PM1-2.5 was the fraction with the highest mass percentage of organics. Acids were the organic compounds that dominated all particle size fractions. Different organic compounds presented apparently different seasonal characteristics, reflecting distinct emission sources, such as vehicle exhausts and biogenic sources. The benzo[a]pyrene equivalent concentrations were lower than 1 ng m- 3. The estimated carcinogenic risk is low.

  2. Structure and composition of vegetation of longleaf pine plantations compared to natural stands occurring along an environmental gradient at the Savannah River Site.

    SciTech Connect

    Smith, Gregory, P.; Shelburne, Victor, B.; Walker, Joan, L.

    2001-12-30

    Study plots in 33-43 year old longleaf pine plantations were compared to remnant longleaf plots on the Savannah River Site in South Carolina. Within these stands, the structure and composition of primarily the herb layer relative to a presumed soil moisture or soil texture gradient was studied using the North Carolina Vegetation Survey methodology. Data were also collected on soils and landform variables. Based on ordination and cluster analyses, both plantation plots and natural stand plots were separated into three distinct site units (xeric, sub-xeric, and sub-mesic). Lack of a major compositional difference between xeric plantation and natural longleaf sites suggests that restoration of the herbaceous layer may not be as complex as once thought. This provides reasonable encouragement for the restoration of the longleaf pine ecosystem.

  3. Correspondence and Least Squares Analyses of Soil and Rock Compositions for the Viking Lander 1 and Pathfinder Sites

    NASA Technical Reports Server (NTRS)

    Larsen, K. W.; Arvidson, R. E.; Jolliff, B. L.; Clark, B. C.

    2000-01-01

    Correspondence and Least Squares Mixing Analysis techniques are applied to the chemical composition of Viking 1 soils and Pathfinder rocks and soils. Implications for the parent composition of local and global materials are discussed.

  4. Experiences from the offshore installation of a composite materials firewater system

    SciTech Connect

    Ciaraldi, S.W.

    1993-12-31

    A prototype 300 m composite dry deluge firewater system was installed in December 1991 at the Valhall Field in the southern North Sea Norwegian offshore sector. This installation followed successful safety verification of the explosion and fire resistant design concept consisting of glass-fiber reinforced epoxy (GRE) piping components protected with a reinforced intumescent epoxy fire insulation. The installation was based primarily on the use of prefabricated GRE piping spools and fire insulation cast onto the piping or applied in the form of cast half shells. Significant experiences gained from the project are described. These experiences involve pre-engineering activities, detailed engineering, onshore fabrication, shipping, offshore hook-up, quality assurance, safety and economics. Although the overall installation was successful and the system is functioning as intended, areas of possible optimization and cost reduction for future composite firewater systems were identified. These findings are also briefly reviewed.

  5. Lung Toxicity of Ambient Particulate Matter from Southeastern U.S. Sites with Different Contributing Sources: Relationships between Composition and Effects

    PubMed Central

    Seagrave, JeanClare; McDonald, Jacob D.; Bedrick, Edward; Edgerton, Eric S.; Gigliotti, Andrew P.; Jansen, John J.; Ke, Lin; Naeher, Luke P.; Seilkop, Steven K.; Zheng, Mei; Mauderly, Joe L.

    2006-01-01

    Background Exposure to air pollution and, more specifically, particulate matter (PM) is associated with adverse health effects. However, the specific PM characteristics responsible for biological effects have not been defined. Objectives In this project we examined the composition, sources, and relative toxicity of samples of PM with aerodynamic diameter ≥2.5 μm (PM2.5) collected from sites within the Southeastern Aerosol Research and Characterization (SEARCH) air monitoring network during two seasons. These sites represent four areas with differing sources of PM2.5, including local urban versus regional sources, urban areas with different contributions of transportation and industrial sources, and a site influenced by Gulf of Mexico weather patterns. Methods We collected samples from each site during the winter and summer of 2004 for toxicity testing and for chemical analysis and chemical mass balance–based source apportionment. We also collected PM2.5 downwind of a series of prescribed forest burns. We assessed the toxicity of the samples by instillation into rat lungs and assessed general toxicity, acute cytotoxicity, and inflammation. Statistical dose–response modeling techniques were used to rank the relative toxicity and compare the seasonal differences at each site. Projection-to-latent-surfaces (PLS) techniques examined the relationships among sources, chemical composition, and toxicologic end points. Results and conclusions Urban sites with high contributions from vehicles and industry were most toxic. PMID:16966093

  6. Mass, black carbon and elemental composition of PM2.5 at an industrial site in Kingston, Jamaica

    NASA Astrophysics Data System (ADS)

    Boman, Johan; Gaita, Samuel M.

    2015-11-01

    An estimated three million premature deaths yearly can be attributed to ambient particulate pollution, a majority of them in low and middle income countries. The rapid increase in the vehicle fleet in urban areas of the Caribbean countries have experienced contributes to the bad urban air quality. In this study aerosol particles with an aerodynamic diameter smaller than, or equal to, 2.5 μm (PM2.5) were collected over 24 h at a site along Spanish Town Road, one of the main commuter roads in Kingston, Jamaica. The study was aimed at determining the mass, black carbon and elemental composition of PM2.5 in Kingston. Although lead in the gasoline was phased out in the year 2000, up to 5000 ppm of sulfur is still allowed in the diesel, leading to an extensive secondary particle formation. PM2.5 samples were collected using a Mini-vol sampler between 12 December 2013 and 21 March 2014 and analyzed for trace elements using the Particle-Induced X-ray Emission (PIXE) facility at Lund University, Sweden. Concentrations of Si, S, Cl, K, Ca, Ti, V, Cr, Fe, Ni, Cu, Zn, Br and Pb were determined. Elemental concentrations showed a high temporal variation and the average PM2.5 concentration (44 μg m-3) is higher than the air quality standards that apply in the European Union (25 μg m-3) and in the USA (12 μg m-3). From this we can conclude that the air quality in the area is severely influenced by PM2.5 pollution and that there is a need to develop plans for improving the air quality in Kingston city.

  7. Temporal variability of atmospheric particulate matter and chemical composition during a growing season at an agricultural site in northeastern China.

    PubMed

    Chen, Weiwei; Tong, Daniel; Zhang, Shichun; Dan, Mo; Zhang, Xuelei; Zhao, Hongmei

    2015-12-01

    This study presents the observations of PM10 and PM2.5 concentrations at an agricultural site from April to October 2012 in Dehui city, China. Ambient air was sampled by filter-based samplers and online PM monitors. The filter samples were analyzed to determine the abundance of ionic/inorganic elements, organic carbon (OC) and elemental carbon (EC). The daily PM10 concentrations varied significantly over the monitoring period, with an average of 168±63 (in the range of 52-277)μg/m(3) during the land preparation/planting period (26 April-15 June), 85±65 (36-228)μg/m(3) during the growing season (16 June-25 September), and 207±88 (103-310)μg/m(3) during the harvest period (26 September-31 October). PM2.5 accounted for 44%, 56% and 66% of atmospheric PM10 during these periods, respectively. The PM10 diurnal variation showed a distinct peak from 16:00 to 21:00 (LST) during the growing and harvesting seasons, while a gradual increase throughout the daytime until 17:00 was observed during tilling season. Mineral dust elements (Al, Ca, Fe, and Mg) dominated the PM10 chemical composition during the tilling season; OC, NO3(-), SO4(2-) and NH4(+) during the growing season; and carbonaceous species (i.e., OC and EC) during the harvesting season. Our results indicate that the soil particles emitted by farm tillage and organic matter released from straw burning are the two most significant sources of PM10 emissions contributing to the recurring high pollution events in this region. Therefore, development of agricultural PM inventories from soil tillage and straw burning is prioritized to support air quality modeling. PMID:26702977

  8. Application of Aerosol Hygroscopicity Measured at the Atmospheric Radiation Measurement Program's Southern Great Plains Site to Examine Composition and Evolution

    NASA Technical Reports Server (NTRS)

    Gasparini, Roberto; Runjun, Li; Collins, Don R.; Ferrare, Richard A.; Brackett, Vincent G.

    2006-01-01

    A Differential Mobility Analyzer/Tandem Differential Mobility Analyzer (DMA/TDMA) was used to measure submicron aerosol size distributions, hygroscopicity, and occasionally volatility during the May 2003 Aerosol Intensive Operational Period (IOP) at the Central Facility of the Atmospheric Radiation Measurement Program's Southern Great Plains (ARM SGP) site. Hygroscopic growth factor distributions for particles at eight dry diameters ranging from 0.012 micrometers to 0.600 micrometers were measured throughout the study. For a subset of particle sizes, more detailed measurements were occasionally made in which the relative humidity or temperature to which the aerosol was exposed was varied over a wide range. These measurements, in conjunction with backtrajectory clustering, were used to infer aerosol composition and to gain insight into the processes responsible for evolution. The hygroscopic growth of both the smallest and largest particles analyzed was typically less than that of particles with dry diameters of about 0.100 micrometers. It is speculated that condensation of secondary organic aerosol on nucleation mode particles is largely responsible for the minimal hygroscopic growth observed at the smallest sizes considered. Growth factor distributions of the largest particles characterized typically contained a nonhygroscopic mode believed to be composed primarily of dust. A model was developed to characterize the hygroscopic properties of particles within a size distribution mode through analysis of the fixed size hygroscopic growth measurements. The performance of this model was quantified through comparison of the measured fixed size hygroscopic growth factor distributions with those simulated through convolution of the size-resolved concentration contributed by each of the size modes and the mode-resolved hygroscopicity. This transformation from sizeresolved hygroscopicity to mode-resolved hygroscopicity facilitated examination of changes in the hygroscopic

  9. Spatial and temporal variability of snow chemical composition and accumulation rate at Talos Dome site (East Antarctica).

    PubMed

    Caiazzo, Laura; Becagli, Silvia; Frosini, Daniele; Giardi, Fabio; Severi, Mirko; Traversi, Rita; Udisti, Roberto

    2016-04-15

    Five snow pits and five firn cores were sampled during the 2003-2004 Italian Antarctic Campaign at Talos Dome (East Antarctica), where a deep ice core (TALDICE, TALos Dome Ice CorE, 1650m depth) was drilled in 2005-2008 and analyzed for ionic content. Particular attention is spent in applying decontamination procedures to the firn cores, as core sections were stored for approximately 10years before analysis. By considering the snow pit samples to be unperturbed, the comparison with firn core samples from the same location shows that ammonium, nitrate and MSA are affected by storage post-depositional losses. All the other measured ions are confirmed to be irreversibly deposited in the snow layer. The removal of the most external layers (few centimeters) from the firn core sections is proved to be an effective decontamination procedure. High-resolution profiles of seasonal markers (nitrate, sulfate and MSA) allow a reliable stratigraphic dating and a seasonal characterization of the samples. The calculated mean accumulation-rate values range from 70 to 85mmw.e.year(-1), in the period 2003-1973 with small differences between two sectors: 70-74mmw.e.year(-1) in the NNE sector (spanning 2003-1996years) and 81-92mmw.e.year(-1) in the SSW sector (spanning 2003-1980years). This evidence is interpreted as a coupled effect of wind-driven redistribution processes in accumulation/ablation areas. Statistical treatment applied to the concentration values of the snow pits and firn cores samples collected in different points reveals a larger temporal variability than spatial one both in terms of concentration of chemical markers and annual accumulation. The low spatial variability of the accumulation rate and chemical composition measured in the five sites demonstrates that the TALDICE ice core paleo-environmental and paleo-climatic stratigraphies can be considered as reliably representative for the Talos Dome area. PMID:26849319

  10. Motif composition, conservation and condition-specificity of single and alternative transcription start sites in the Drosophila genome

    PubMed Central

    Rach, Elizabeth A; Yuan, Hsiang-Yu; Majoros, William H; Tomancak, Pavel; Ohler, Uwe

    2009-01-01

    Background Transcription initiation is a key component in the regulation of gene expression. mRNA 5' full-length sequencing techniques have enhanced our understanding of mammalian transcription start sites (TSSs), revealing different initiation patterns on a genomic scale. Results To identify TSSs in Drosophila melanogaster, we applied a hierarchical clustering strategy on available 5' expressed sequence tags (ESTs) and identified a high quality set of 5,665 TSSs for approximately 4,000 genes. We distinguished two initiation patterns: 'peaked' TSSs, and 'broad' TSS cluster groups. Peaked promoters were found to contain location-specific sequence elements; conversely, broad promoters were associated with non-location-specific elements. In alignments across other Drosophila genomes, conservation levels of sequence elements exceeded 90% within the melanogaster subgroup, but dropped considerably for distal species. Elements in broad promoters had lower levels of conservation than those in peaked promoters. When characterizing the distributions of ESTs, 64% of TSSs showed distinct associations to one out of eight different spatiotemporal conditions. Available whole-genome tiling array time series data revealed different temporal patterns of embryonic activity across the majority of genes with distinct alternative promoters. Many genes with maternally inherited transcripts were found to have alternative promoters utilized later in development. Core promoters of maternally inherited transcripts showed differences in motif composition compared to zygotically active promoters. Conclusions Our study provides a comprehensive map of Drosophila TSSs and the conditions under which they are utilized. Distinct differences in motif associations with initiation pattern and spatiotemporal utilization illustrate the complex regulatory code of transcription initiation. PMID:19589141

  11. 2008 Annual Summary Report for the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada Test Site, Nye County, Nevada: Review of the Performance Assessments and Composite Analyses

    SciTech Connect

    NSTec Environmental Management

    2009-03-30

    The Maintenance Plan for the Performance Assessments and Composite Analyses for the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada Test Site requires an annual review to assess the adequacy of the Performance Assessments (PAs) and Composite Analyses (CAs) for each of the facilities, with the results submitted annually to U.S. Department of Energy (DOE) Headquarters. The Disposal Authorization Statements for the Area 3 and Area 5 Radioactive Waste Management Sites (RWMSs) also require that such reviews be made and that secondary or minor unresolved issues be tracked and addressed as part of the maintenance plan. The U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office (NNSA/NSO) performed an annual review in fiscal year (FY) 2008 by evaluating operational factors and research results that impact the continuing validity of the PAs and CAs. This annual summary report presents data and conclusions from the FY 2008 review, and determines the adequacy of the PAs and CAs. Operational factors (e.g., waste forms and containers, facility design, and waste receipts), closure plans, monitoring results, and research and development (R&D) activities were reviewed to determine the adequacy of the PAs. Likewise, the environmental restoration activities at the Nevada Test Site relevant to the sources of residual radioactive material that are considered in the CAs, the land-use planning, and the results of the environmental monitoring and R&D activities were reviewed to determine the adequacy of the CAs.

  12. CUSTOM WATERSHEDS AND LANDSCAPE METRICS FOR EMAP-GRE SAMPLE SITES ON THE MISSISSIPPI, THE MISSOURI AND THE OHIO RIVERS: GIS APPROACH

    EPA Science Inventory

    This research and work is a novel use of the latest advancement of a hydrology-with-elevation seamless data layer for the entire United States, namely NDHPlus and for the newest (ca 2001) imaging and classification of land cover, the National Land Cover Database (NLCD 2001) which...

  13. Chemical composition of North American microtektites and tektite fragments from Barbados and DSDP site 612 on the continental slope off New Jersey

    NASA Astrophysics Data System (ADS)

    Koeberl, C.; Glass, B. P.

    1988-02-01

    The major element and trace element content of tektite fragments and microtektites found in deep-sea sediments from Barbados and DSDP (Deep Sea Drilling Project) Site 612 on the continental slope off New Jersey have been determined. The compositions are consistent with the conclusion that the samples from both occurrences belong to the North American tektite strewn field. However, the chemistry of the samples from both occurrences is not identical with the bediasite or georgianite chemistry. These differences show that there are geographical variations in composition in the North American strewn field.

  14. Thermal Evolution and Composition of the July 2009 Jupiter Impact Site from 7-25 Micron Imaging and Spectroscopy

    NASA Astrophysics Data System (ADS)

    Fletcher, L. N.; Orton, G. S.; Mousis, O.; de Pater, I.; Hammel, H. B.; Golisch, W.; Edwards, M.; Yanamandra-Fisher, P. A.; Fisher, B.; Greene, Z.; Lai, S.; Otto, E.; Reshetnikov, N.; Sanchez-Lavega, A.; Simon-Miller, A. A.; Hueso, R.; Perez-Hoyos, S.

    2009-12-01

    narrow wavelength ranges near 8.02, 10.49, 11.31, 11.60, 12.24 and 13.36 microns, sensitive to NH3, CH4 and hydrocarbon emission features. Iterative forward modelling of these spectra will be used to deduce the unique chemical composition and the three-dimensional thermal structure of the impact site, compared with the ‘unperturbed’ atmosphere at the same latitude. * Fletcher is supported by an appointment to the NASA Postdoctoral Program at the Jet Propulsion Laboratory/California Institute of Technology, administered by Oak Ridge Associated Universities through a contract with NASA. We wish to acknowledge the invaluable contributions of the support staff at IRTF, VLT and Gemini.

  15. Sorption testing and generalized composite surface complexation models for determining uranium sorption parameters at a proposed in-situ recovery site

    DOE PAGESBeta

    Johnson, Raymond H.; Truax, Ryan A.; Lankford, David A.; Stone, James J.

    2016-02-03

    Solid-phase iron concentrations and generalized composite surface complexation models were used to evaluate procedures in determining uranium sorption on oxidized aquifer material at a proposed U in situ recovery (ISR) site. At the proposed Dewey Burdock ISR site in South Dakota, USA, oxidized aquifer material occurs downgradient of the U ore zones. Solid-phase Fe concentrations did not explain our batch sorption test results,though total extracted Fe appeared to be positively correlated with overall measured U sorption. Batch sorption test results were used to develop generalized composite surface complexation models that incorporated the full genericsorption potential of each sample, without detailedmore » mineralogiccharacterization. The resultant models provide U sorption parameters (site densities and equilibrium constants) for reactive transport modeling. The generalized composite surface complexation sorption models were calibrated to batch sorption data from three oxidized core samples using inverse modeling, and gave larger sorption parameters than just U sorption on the measured solidphase Fe. These larger sorption parameters can significantly influence reactive transport modeling, potentially increasing U attenuation. Because of the limited number of calibration points, inverse modeling required the reduction of estimated parameters by fixing two parameters. The best-fit models used fixed values for equilibrium constants, with the sorption site densities being estimated by the inversion process. While these inverse routines did provide best-fit sorption parameters, local minima and correlated parameters might require further evaluation. Despite our limited number of proxy samples, the procedures presented provide a valuable methodology to consider for sites where metal sorption parameters are required. Furthermore, these sorption parameters can be used in reactive transport modeling to assess downgradient metal attenuation, especially when no other

  16. Prediction of mucin-type O-glycosylation sites in mammalian proteins using the composition of k-spaced amino acid pairs

    PubMed Central

    Chen, Yong-Zi; Tang, Yu-Rong; Sheng, Zhi-Ya; Zhang, Ziding

    2008-01-01

    Background As one of the most common protein post-translational modifications, glycosylation is involved in a variety of important biological processes. Computational identification of glycosylation sites in protein sequences becomes increasingly important in the post-genomic era. A new encoding scheme was employed to improve the prediction of mucin-type O-glycosylation sites in mammalian proteins. Results A new protein bioinformatics tool, CKSAAP_OGlySite, was developed to predict mucin-type O-glycosylation serine/threonine (S/T) sites in mammalian proteins. Using the composition of k-spaced amino acid pairs (CKSAAP) based encoding scheme, the proposed method was trained and tested in a new and stringent O-glycosylation dataset with the assistance of Support Vector Machine (SVM). When the ratio of O-glycosylation to non-glycosylation sites in training datasets was set as 1:1, 10-fold cross-validation tests showed that the proposed method yielded a high accuracy of 83.1% and 81.4% in predicting O-glycosylated S and T sites, respectively. Based on the same datasets, CKSAAP_OGlySite resulted in a higher accuracy than the conventional binary encoding based method (about +5.0%). When trained and tested in 1:5 datasets, the CKSAAP encoding showed a more significant improvement than the binary encoding. We also merged the training datasets of S and T sites and integrated the prediction of S and T sites into one single predictor (i.e. S+T predictor). Either in 1:1 or 1:5 datasets, the performance of this S+T predictor was always slightly better than those predictors where S and T sites were independently predicted, suggesting that the molecular recognition of O-glycosylated S/T sites seems to be similar and the increase of the S+T predictor's accuracy may be a result of expanded training datasets. Moreover, CKSAAP_OGlySite was also shown to have better performance when benchmarked against two existing predictors. Conclusion Because of CKSAAP encoding's ability of

  17. 2009 Annual Summary Report for the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada Test Site, Nye County, Nevada: Review of the Performance Assessments and Composite Analysis

    SciTech Connect

    NSTec Environmental Management

    2010-03-15

    The U.S. Department of Energy, National Nuclear Security Administration Nevada Site Office performed an annual review of the Area 3 and Area 5 Radioactive Wate Management Site (RWMS) Performance Assessments (PAs) and Composite Analyses (CAs) in fiscal year (FY) 2009. This annual summary report presents data and conclusions from the FY 2009 review, and determines the adequacy of the PAs and CAs. Operational factors (e.g., waste forms and containers, facility design, and waste receipts), closure plans, monitoring results, and research and development (R&D) activities were reviewed to determine the adequacy of the PAs. Likewise, the environmental restoration activities at the Nevada Test Site relevant to the sources of residual radioactive material that are considered in the CAs, the land-use planning, and the results of the environmental monitoring and R&D activities were reviewed to determine the adequacy of the CAs.

  18. Technical refinements of composite thoracodorsal system free flaps for 1-stage lower extremity reconstruction resulting in reduced donor-site morbidity.

    PubMed

    Bannasch, Holger; Strohm, Peter C; Al Awadi, Khalid; Stark, G Björn; Momeni, Arash

    2008-04-01

    A multitude of local flaps has been suggested for lower extremity reconstruction. However, the gold standard for defect coverage remains free tissue transfer. In this regard, the scapular vascular axis is a well-established source of expendable skin, fascia, muscle, and bone for use in free flap reconstruction of defects requiring bone and soft tissue in complex 3-dimensional relationships. Composite bone and soft-tissue flaps derived from the subscapular vascular axis include the osteocutaneous scapular flap, the "latissimus/bone flap," and the thoracodorsal artery perforator-scapular osteocutaneous flap.Patient outcome following reconstruction of lower extremity defects with composite free flaps from the thoracodorsal system were analyzed. Here, we demonstrate the execution of technical refinements on free composite flap transfers based on the thoracodorsal vascular axis, thus resulting in a stepwise reduction of donor-site morbidity. PMID:18362565

  19. Feasibility of T2* mapping for the evaluation of hip joint cartilage at 1.5T using a three-dimensional (3D), gradient-echo (GRE) sequence: a prospective study.

    PubMed

    Bittersohl, Bernd; Hosalkar, Harish S; Hughes, Tim; Kim, Young-Jo; Werlen, Stefan; Siebenrock, Klaus A; Mamisch, Tallal C

    2009-10-01

    This study defines the feasibility of utilizing three-dimensional (3D) gradient-echo (GRE) MRI at 1.5T for T(2)* mapping to assess hip joint cartilage degenerative changes using standard morphological MR grading while comparing it to delayed gadolinium-enhanced MRI of cartilage (dGEMRIC). MRI was obtained from 10 asymptomatic young adult volunteers and 33 patients with symptomatic femoroacetabular impingement (FAI). The protocol included T(2)* mapping without gadolinium-enhancement utilizing a 3D-GRE sequence with six echoes, and after gadolinium injection, routine hip sequences, and a dual-flip-angle 3D-GRE sequence for dGEMRIC T(1) mapping. Cartilage was classified as normal, with mild changes, or with severe degenerative changes based on morphological MRI. T(1) and T(2)* findings were subsequently correlated. There were significant differences between volunteers and patients in normally-rated cartilage only for T(1) values. Both T(1) and T(2)* values decreased significantly with the various grades of cartilage damage. There was a statistically significant correlation between standard MRI and T(2)* (T(1)) (P < 0.05). High intraclass correlation was noted for both T(1) and T(2)*. Correlation factor was 0.860 to 0.954 (T(2)*-T(1) intraobserver) and 0.826 to 0.867 (T(2)*-T(1) interobserver). It is feasible to gather further information about cartilage status within the hip joint using GRE T(2)* mapping at 1.5T. PMID:19645008

  20. Bats Swarm Where They Hibernate: Compositional Similarity between Autumn Swarming and Winter Hibernation Assemblages at Five Underground Sites.

    PubMed

    van Schaik, Jaap; Janssen, René; Bosch, Thijs; Haarsma, Anne-Jifke; Dekker, Jasja J A; Kranstauber, Bart

    2015-01-01

    During autumn in the temperate zone of both the new and old world, bats of many species assemble at underground sites in a behaviour known as swarming. Autumn swarming behaviour is thought to primarily serve as a promiscuous mating system, but may also be related to the localization and assessment of hibernacula. Bats subsequently make use of the same underground sites during winter hibernation, however it is currently unknown if the assemblages that make use of a site are comparable across swarming and hibernation seasons. Our purpose was to characterize the bat assemblages found at five underground sites during both the swarming and the hibernation season and compare the assemblages found during the two seasons both across sites and within species. We found that the relative abundance of individual species per site, as well as the relative proportion of a species that makes use of each site, were both significantly correlated between the swarming and hibernation seasons. These results suggest that swarming may indeed play a role in the localization of suitable hibernation sites. Additionally, these findings have important conservation implications, as this correlation can be used to improve monitoring of underground sites and predict the importance of certain sites for rare and cryptic bat species. PMID:26153691

  1. Bats Swarm Where They Hibernate: Compositional Similarity between Autumn Swarming and Winter Hibernation Assemblages at Five Underground Sites

    PubMed Central

    van Schaik, Jaap; Janssen, René; Bosch, Thijs; Haarsma, Anne-Jifke; Dekker, Jasja J. A.; Kranstauber, Bart

    2015-01-01

    During autumn in the temperate zone of both the new and old world, bats of many species assemble at underground sites in a behaviour known as swarming. Autumn swarming behaviour is thought to primarily serve as a promiscuous mating system, but may also be related to the localization and assessment of hibernacula. Bats subsequently make use of the same underground sites during winter hibernation, however it is currently unknown if the assemblages that make use of a site are comparable across swarming and hibernation seasons. Our purpose was to characterize the bat assemblages found at five underground sites during both the swarming and the hibernation season and compare the assemblages found during the two seasons both across sites and within species. We found that the relative abundance of individual species per site, as well as the relative proportion of a species that makes use of each site, were both significantly correlated between the swarming and hibernation seasons. These results suggest that swarming may indeed play a role in the localization of suitable hibernation sites. Additionally, these findings have important conservation implications, as this correlation can be used to improve monitoring of underground sites and predict the importance of certain sites for rare and cryptic bat species. PMID:26153691

  2. Inducible scAAV2.GRE.MMP1 lowers IOP long-term in a large animal model for steroid-induced glaucoma gene therapy

    PubMed Central

    Borrás, Teresa; Buie, LaKisha K.; Spiga, Maria Grazia

    2016-01-01

    Current treatment of glaucoma relies on administration of daily drops or eye surgery. A gene therapy approach to treat steroid-induced glaucoma would bring a resolution to millions of people worldwide that depend on glucocorticoid therapy for a myriad of inflammatory disorders. Previously, we had characterized a short-term Adh.GRE.MMP1 gene vector for the production of steroid-induced MMP1 in the trabecular meshwork and tested reduction of elevated intraocular pressure (IOP) in a sheep model. Here we conducted a trial transferring the same transgene cassette to a clinically safe vector (scAAV2), and extended the therapeutic outcome to longer periods of times. No evidence of ocular and/or systemic toxicity was observed. Viral genome distributions showed potential re-inducible vector DNAs in the trabecular meshwork (0.4 vg/cell) and negligible copies in six major internal organs (0.00002-0.005 vg/cell). Histological sections confirmed successful transduction of scAAV2.GFP to the trabecular meshwork. Optimization of the sheep steroid–induced hypertensive model revealed that topical ophthalmic drug difluprednate 0.05% (durezol) induced the highest IOP elevation in the shortest time. This is the first efficacy/toxicity study of a feasible gene therapy treatment of steroid-induced hypertension using clinically accepted scAAV vectors in a large animal model. PMID:26855269

  3. Inducible scAAV2.GRE.MMP1 lowers IOP long-term in a large animal model for steroid-induced glaucoma gene therapy.

    PubMed

    Borrás, T; Buie, L K; Spiga, M G

    2016-05-01

    Current treatment of glaucoma relies on administration of daily drops or eye surgery. A gene therapy approach to treat steroid-induced glaucoma would bring a resolution to millions of people worldwide who depend on glucocorticoid therapy for a myriad of inflammatory disorders. Previously, we had characterized a short-term Adh.GRE.MMP1 gene vector for the production of steroid-induced MMP1 in the trabecular meshwork and tested reduction of elevated intraocular pressure (IOP) in a sheep model. Here we conducted a trial transferring the same transgene cassette to a clinically safe vector (scAAV2), and extended the therapeutic outcome to longer periods of times. No evidence of ocular and/or systemic toxicity was observed. Viral genome distributions showed potential reinducible vector DNAs in the trabecular meshwork (0.4 v.g. per cell) and negligible copies in six major internal organs (0.00002-0.005 v.g. per cell). Histological sections confirmed successful transduction of scAAV2.GFP to the trabecular meshwork. Optimization of the sheep steroid-induced hypertensive model revealed that topical ophthalmic drug difluprednate 0.05% (durezol) induced the highest IOP elevation in the shortest time. This is the first efficacy/toxicity study of a feasible gene therapy treatment of steroid-induced hypertension using clinically accepted self-complementary adeno-associated vectors (scAAV) vectors in a large animal model. PMID:26855269

  4. Maintenance Plan for the Performance Assessments and Composite Analyses for the Area 3 and Area 5 Radioactive Waste Management Sites at the NTS

    SciTech Connect

    Vefa Yucel

    2007-01-03

    U.S. Department of Energy (DOE) Manual M 435.1-1 requires that performance assessments (PAs) and composite analyses (CAs) for low-level waste (LLW) disposal facilities be maintained by the field offices. This plan describes the activities performed to maintain the PA and the CA for the Area 3 and Area 5 Radioactive Waste Management Sites (RWMSs) at the Nevada Test Site (NTS). This plan supersedes the Maintenance Plan for the Performance Assessments and Composite Analyses for the Area 3 and Area 5 Radioactive Waste Management Sites at the Nevada Test Site (DOE/NV/11718--491-REV 1, dated September 2002). The plan is based on U.S. Department of Energy (DOE) Order 435.1 (DOE, 1999a), DOE Manual M 435.1-1 (DOE, 1999b), the DOE M 435.1-1 Implementation Guide DOE G 435.1-1 (DOE, 1999c), and the Maintenance Guide for PAs and CAs (DOE, 1999d). The plan includes a current update on PA/CA documentation, a revised schedule, and a section on Quality Assurance.

  5. Impacts of aggregate dredging on sediment composition and associated benthic fauna at an offshore dredge site in the southern North Sea.

    PubMed

    Robinson, J E; Newell, R C; Seiderer, L J; Simpson, N M

    2005-07-01

    Dredging and associated screening at a dredge site in the southern North Sea (Area 408) is associated with areas of well-sorted fine sand that extend for up to 3 km to the south-east of the dredged area and overlay sediments with a more variable particle size composition. This well-sorted fine sand may reflect deposition and transport of material mobilised by the dredging and screening processes at the dredge site. Multivariate analysis of the benthic community structure suggests that marine aggregate dredging, at the level of intensity employed in the study area prior to sample collection, has had a limited impact on benthic community composition compared with that reported from studies elsewhere. This is ascribed to the likely rapid rates of recolonisation by the mobile opportunistic polychaetes and crustaceans that dominate the macrofauna of the sandy gravel deposits at this particular dredge site. Analysis of variance showed, however, that significant differences existed between the sample treatments in terms of species evenness (Pielou's J). Dredged samples were found to have the lowest mean species evenness (0.71) when compared to controls (0.77). The present study highlights the inherent difficulties in the application of general impact/recovery predictions to dredged sites with varying environmental characteristics. PMID:15649527

  6. Incorporating substrate sequence motifs and spatial amino acid composition to identify kinase-specific phosphorylation sites on protein three-dimensional structures

    PubMed Central

    2013-01-01

    Background Protein phosphorylation catalyzed by kinases plays crucial regulatory roles in cellular processes. Given the high-throughput mass spectrometry-based experiments, the desire to annotate the catalytic kinases for in vivo phosphorylation sites has motivated. Thus, a variety of computational methods have been developed for performing a large-scale prediction of kinase-specific phosphorylation sites. However, most of the proposed methods solely rely on the local amino acid sequences surrounding the phosphorylation sites. An increasing number of three-dimensional structures make it possible to physically investigate the structural environment of phosphorylation sites. Results In this work, all of the experimental phosphorylation sites are mapped to the protein entries of Protein Data Bank by sequence identity. It resulted in a total of 4508 phosphorylation sites containing the protein three-dimensional (3D) structures. To identify phosphorylation sites on protein 3D structures, this work incorporates support vector machines (SVMs) with the information of linear motifs and spatial amino acid composition, which is determined for each kinase group by calculating the relative frequencies of 20 amino acid types within a specific radial distance from central phosphorylated amino acid residue. After the cross-validation evaluation, most of the kinase-specific models trained with the consideration of structural information outperform the models considering only the sequence information. Furthermore, the independent testing set which is not included in training set has demonstrated that the proposed method could provide a comparable performance to other popular tools. Conclusion The proposed method is shown to be capable of predicting kinase-specific phosphorylation sites on 3D structures and has been implemented as a web server which is freely accessible at http://csb.cse.yzu.edu.tw/PhosK3D/. Due to the difficulty of identifying the kinase-specific phosphorylation

  7. Summary of inorganic compositional data for groundwater, soil-water, and surface-water samples collected at the Headgate Draw subsurface drip irrigation site, Johnson County, Wyoming

    USGS Publications Warehouse

    Geboy, Nicholas J.; Engle, Mark A.; Schroeder, Karl T.; Zupancic, John W.

    2011-01-01

    As part of a 5-year project on the impact of subsurface drip irrigation (SDI) application of coalbed-methane (CBM) produced waters, water samples were collected from the Headgate Draw SDI site in the Powder River Basin, Wyoming, USA. This research is part of a larger study to understand short- and long-term impacts on both soil and water quality from the beneficial use of CBM waters to grow forage crops through use of SDI. This document provides a summary of the context, sampling methodology, and quality assurance and quality control documentation of samples collected prior to and over the first year of SDI operation at the site (May 2008-October 2009). This report contains an associated database containing inorganic compositional data, water-quality criteria parameters, and calculated geochemical parameters for samples of groundwater, soil water, surface water, treated CBM waters, and as-received CBM waters collected at the Headgate Draw SDI site.

  8. Summary of Inorganic Compositional Data for Groundwater, Soil-Water, and Surface-Water Samples at the Headgate Draw Subsurface Drip Irrigation Site

    SciTech Connect

    Geboy, Nicholas J.; Engle, Mark A.; Schroeder, Karl T.; Zupanic, John W.

    2007-01-01

    As part of a 5-year project on the impact of subsurface drip irrigation (SDI) application of coalbed-methane (CBM) produced waters, water samples were collected from the Headgate Draw SDI site in the Powder River Basin, Wyoming, USA. This research is part of a larger study to understand short- and long-term impacts on both soil and water quality from the beneficial use of CBM waters to grow forage crops through use of SDI. This document provides a summary of the context, sampling methodology, and quality assurance and quality control documentation of samples collected prior to and over the first year of SDI operation at the site (May 2008-October 2009). This report contains an associated database containing inorganic compositional data, water-quality criteria parameters, and calculated geochemical parameters for samples of groundwater, soil water, surface water, treated CBM waters, and as-received CBM waters collected at the Headgate Draw SDI site.

  9. The effects of crushing speed on the energy-absorption capability of composite material

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.

    1987-01-01

    The energy-absorption capability as a function of crushing speed was determined for Thornel 300/Fiberite 934 (Gr/E) and Kevlar-49/Fiberite 934 (K/E) composite material. Circular cross section tube specimens were crushed at quasi-static, 6 m/sec, and 12 m/sec speeds. Ply orientations of the tube specimens were (0/+ or - theta) sub 2 and (+ or - theta) sub 3 where theta=15, 45, and 75 degress. Based on the results of these tests the energy-absortion capability of Gr/E and K/E was determined to be a function of crushing speed. The crushing modes based on exterior appearance of the crushed tubes were unchanged for either material. However, the interlaminar crushing behavior changed with crushing speed.

  10. Hygroscopicity Behavior, Activation Properties and Chemical Composition of Atmospheric Aerosol at a Background Site in the Megacity Region of Peking

    NASA Astrophysics Data System (ADS)

    Henning, Silvia; Nowak, Andreas; Mildenberger, Katrin; Göbel, Tina; Nekat, Bettina; van Pinxteren, Dominik; Herrmann, Hartmut; Zhao, Chunsheng; Wiedensohler, Alfred; Stratmann, Frank

    2010-05-01

    Large areas of China suffer from heavy air pollution (both gaseous and particulate) caused by strong economic growth in the last two decades. However, knowledge concerning the physical and chemical properties of the resulting aerosol particles populations, and their effects on the optical properties of the atmosphere, is still sparse. In the framework of the investigations presented here, comprehensive measurements concerning aerosol particle hygroscopicity, CCN ability, composition, and optical properties were performed. The investigations are part of the DFG-funded project HaChi (Haze in China) and are conducted in collaboration with the Peking University. A conclusive parameterization of aerosol hygroscopicity and activation data is aimed for, which will then be implemented in a meso-scale model to investigate aerosol-cloud-radiation and precipitation interactions. During two intensive measurements campaigns (March 2009 and July/ August 2009), in-situ aerosol measurements have been performed in an air-conditioned mobile laboratory next to the Wuqing Meteorological Station (39°23'8.53"N, 117°1'25.88"E), which is located between Bejing and Tijanjin and is thereby an ideal background site in a megacity region. The particle number size distribution (TDMPS), the particle optical properties (MAAP and nephelometer) and their hygroscopic properties at high RH (HH-TDMA, LACIS-mobile) were characterized as well as their cloud nucleating properties above supersaturation (DMT-CCNC). 24 h PM1 particle samples were continuously collected over the two campaigns in winter and summer using a DIGITEL high volume sampler (DHA-80). Additionally two 6h size-resolved samples (daytime and night-time) were collected each day applying an 11-stage Berner impactor. The size-selection of HH-TDMA, LACIS and the CCNC was synchronized with the Berner stages. Opening analysis of the winter campaign data showed that the HH-TDMA usually detected a hydrophobic and a hygroscopic mode, i.e., the

  11. Ionic composition of PM2.5 at urban sites of northern Greece: secondary inorganic aerosol formation.

    PubMed

    Voutsa, D; Samara, C; Manoli, E; Lazarou, D; Tzoumaka, P

    2014-04-01

    This study investigates the water-soluble ionic constituents (Na(+), K(+), NH4 (+), Ca(2+), Mg(2+), Cl(-), NO3 (-), SO4 (2-)) associated to PM2.5 particle fraction at two urban sites in the city of Thessaloniki, northern Greece, an urban traffic site (UT) and urban background site (UB). Ionic constituents represent a significant fraction of PM2.5 mass (29.6 at UT and 41.5 % at UB). The contribution of marine aerosol was low (<1.5 %). Secondary inorganic aerosols (SIA) represent a significant fraction of PM2.5 mass contributing to 26.9 ± 12.4 % and 39.2 ± 13.2 % at UT and UB sites, respectively. Nitrate and sulfate are fully neutralized by ammonium under the existing conditions. The ionic constituents were evaluated in relation to their spatial and temporal variation, their gaseous precursors, meteorological conditions, local and long-range transport. PMID:24363054

  12. Atmospheric fate of nuclei-mode particles estimated from the number concentrations and chemical composition of particles measured at roadside and background sites

    NASA Astrophysics Data System (ADS)

    Fushimi, Akihiro; Hasegawa, Shuichi; Takahashi, Katsuyuki; Fujitani, Yuji; Tanabe, Kiyoshi; Kobayashi, Shinji

    Number concentrations and size-resolved chemical compositions of atmospheric particles at a roadside site in Kawasaki City, Japan, and a background site 200 m away were measured in winter to estimate the atmospheric fate of nuclei-mode particles emitted from vehicles. Measurements with a scanning mobility particle sizer showed a sharp peak in nuclei-mode particles with a modal diameter of around 0.020 μm at the roadside site; in contrast, no peak for nuclei-mode particles was observed at the background site. For chemical analysis, size-resolved particles were sampled by low-pressure impactors. Carbon analysis suggested that diesel exhaust particles contributed to both the roadside and background Stage 1 (S1; 0.030-0.060 μm) particles. The ratios of organic carbon (OC) to total carbon (TC) increased for smaller particles, and were 28% and 51% for the roadside and the background S1 particles, respectively. It is likely that the OC/TC ratio for nuclei-mode particles was larger than for the S1 particles, and that OC was one of the major constituents of the nuclei-mode particles at the roadside site. From this result and the greater Kelvin effect for smaller particles, it is likely that nuclei-mode particles in the roadside atmosphere are more volatile than the S1 particles. Organic analysis of the size-resolved particles suggested that lubricating oil from vehicles affected the organic composition of both the roadside and background S1 particles, and that C 33n-alkane and more volatile organic compounds in the S1 particles partially evaporated in the atmosphere following the emission of the particles from diesel vehicles. It is likely that evaporation of the constituents (or possibly coagulation with pre-existing particles after shrinking by partial evaporation) of the nuclei-mode particles in the atmosphere was responsible for the absence of nuclei-mode particles in the background atmosphere.

  13. Chemical compositions of some soils and rock types from the Apollo 15, 16, and 17 lunar sites

    NASA Technical Reports Server (NTRS)

    Nava, D. F.

    1974-01-01

    The major and minor element compositions of three Apollo 15 mare basalts, four Apollo 16 breccias, one soil, three Apollo 17 soils, one mare basalt, and one breccia have been determined by semimicro combined atomic absorption and colorimetric spectrophotometries. A discussion regarding analysis of small subsamples of coarse-grained lunar materials, such as certain Apollo 15 and 17 basalts, is given in which the suggestion is made that analytical methods designed to determine the bulk 'representative' chemical composition as well as the presence and extent of specimen heterogeneity are fundamentally necessary for a more complete understanding of genesis and history of lunar materials.

  14. Strontium Isotopic Composition of Paleozoic Carbonate Rocks in the Nevada Test Site Vicinity, Clark, Lincoln, and Nye Counties, Nevada, and Inyo County, California

    USGS Publications Warehouse

    Paces, James B.; Peterman, Zell E.; Futo, Kiyoto; Oliver, Thomas A.; Marshall, Brian D.

    2007-01-01

    Ground water moving through permeable Paleozoic carbonate rocks represents the most likely pathway for migration of radioactive contaminants from nuclear weapons testing at the Nevada Test Site, Nye County, Nevada. The strontium isotopic composition (87Sr/86Sr) of ground water offers a useful means of testing hydrochemical models of regional flow involving advection and reaction. However, reaction models require knowledge of 87Sr/86Sr data for carbonate rock in the Nevada Test Site vicinity, which is scarce. To fill this data gap, samples of core or cuttings were selected from 22 boreholes at depth intervals from which water samples had been obtained previously around the Nevada Test Site at Yucca Flat, Frenchman Flat, Rainier Mesa, and Mercury Valley. Dilute acid leachates of these samples were analyzed for a suite of major- and trace-element concentrations (MgO, CaO, SiO2, Al2O3, MnO, Rb, Sr, Th, and U) as well as for 87Sr/86Sr. Also presented are unpublished analyses of 114 Paleozoic carbonate samples from outcrops, road cuts, or underground sites in the Funeral Mountains, Bare Mountain, Striped Hills, Specter Range, Spring Mountains, and ranges east of the Nevada Test Site measured in the early 1990's. These data originally were collected to evaluate the potential for economic mineral deposition at the potential high-level radioactive waste repository site at Yucca Mountain and adjacent areas (Peterman and others, 1994). Samples were analyzed for a suite of trace elements (Rb, Sr, Zr, Ba, La, and Ce) in bulk-rock powders, and 87Sr/86Sr in partial digestions of carbonate rock using dilute acid or total digestions of silicate-rich rocks. Pre-Tertiary core samples from two boreholes in the central or western part of the Nevada Test Site also were analyzed. Data are presented in tables and summarized in graphs; however, no attempt is made to interpret results with respect to ground-water flow paths in this report. Present-day 87Sr/86Sr values are compared to values

  15. Strontium Isotopic Composition of Paleozoic Carbonate Rocks in the Nevada Test Site Vicinity, Clark, Lincoln, and Nye Counties, Nevada and Inyo County, California.

    SciTech Connect

    James B. Paces; Zell E. Peterman; Kiyoto Futa; Thomas A. Oliver; and Brian D. Marshall.

    2007-08-07

    Ground water moving through permeable Paleozoic carbonate rocks represents the most likely pathway for migration of radioactive contaminants from nuclear weapons testing at the Nevada Test Site, Nye County, Nevada. The strontium isotopic composition (87Sr/86Sr) of ground water offers a useful means of testing hydrochemical models of regional flow involving advection and reaction. However, reaction models require knowledge of 87Sr/86Sr data for carbonate rock in the Nevada Test Site vicinity, which is scarce. To fill this data gap, samples of core or cuttings were selected from 22 boreholes at depth intervals from which water samples had been obtained previously around the Nevada Test Site at Yucca Flat, Frenchman Flat, Rainier Mesa, and Mercury Valley. Dilute acid leachates of these samples were analyzed for a suite of major- and trace-element concentrations (MgO, CaO, SiO2, Al2O3, MnO, Rb, Sr, Th, and U) as well as for 87Sr/86Sr. Also presented are unpublished analyses of 114 Paleozoic carbonate samples from outcrops, road cuts, or underground sites in the Funeral Mountains, Bare Mountain, Striped Hills, Specter Range, Spring Mountains, and ranges east of the Nevada Test Site measured in the early 1990's. These data originally were collected to evaluate the potential for economic mineral deposition at the potential high-level radioactive waste repository site at Yucca Mountain and adjacent areas (Peterman and others, 1994). Samples were analyzed for a suite of trace elements (Rb, Sr, Zr, Ba, La, and Ce) in bulk-rock powders, and 87Sr/86Sr in partial digestions of carbonate rock using dilute acid or total digestions of silicate-rich rocks. Pre-Tertiary core samples from two boreholes in the central or western part of the Nevada Test Site also were analyzed. Data are presented in tables and summarized in graphs; however, no attempt is made to interpret results with respect to ground-water flow paths in this report. Present-day 87Sr/86Sr values are compared to values

  16. Chemical Compositions of Precipitation at Three Non-urban Sites of Hebei Province, North China: Influence of Terrestrial Sources on Ionic Composition

    NASA Astrophysics Data System (ADS)

    Xu, Z.

    2015-12-01

    Rapid economic development and increased energy demand have resulted in severe air pollution problems throughout China, and the increasing emissions of SO2 and NOx have led to significant deposition of acid rain in China. Despite high SO2 concentrations are observed in both southern and northern China, acid rain is mainly observed in the south area in history. It is believed that high content of alkaline matters in the soil in the North China is one of the key factors that contribute to the neutralization of acidic ions in the rainwater. However, an increasing trend of the precipitation acidity was observed at many sites in North, Central and East China after 2000, with more pronounced trends in the Beijing-Tianjin region and Bohai Sea surrounding area. In this study, precipitations were collected from April to October in 2008 at three non-urban sites (Chicheng, Huailai and Xuanhua) in Hebei Province, North China. The pH values of precipitation events ranged from 4.08 to 7.53 for the three sampling sites. About 61.8% of the total precipitation had a pH value higher than 6.0. The predominant ions in the precipitation were SO42-, NO3- and Ca2+, and their concentrations were significantly higher than other sites in South China. The high concentration of acidic ions reflects that atmospheric pollution has already been severe in this area. The volume-weighted mean (VWM) concentration of major ions and pH value showed obvious seasonal differences, precipitation in dry season had high pH values and VWM concentrations of major ions. According to the equivalent ratio of NP/AP and the results of neutralization factors, the strong acid neutralization is mainly brought about by Ca2+ followed by NH4+ and Mg2+. Using Na as an indicator of marine origin, the proportions of sea salt and non-sea-salt were estimated from elemental ratios. Combining with the results of correlation analysis and enrichment factors, the main acidic ions (SO42- and NO3-) and NH4+ were mainly derived from

  17. Evaluation of the Community Multiscale Air Quality (CMAQ) model v5.0 against size-resolved measurements of inorganic particle composition across sites in North America

    NASA Astrophysics Data System (ADS)

    Nolte, C. G.; Appel, K. W.; Kelly, J. T.; Bhave, P. V.; Fahey, K. M.; Collett, J. L., Jr.; Zhang, L.; Young, J. O.

    2015-09-01

    This work evaluates particle size-composition distributions simulated by the Community Multiscale Air Quality (CMAQ) model using micro-orifice uniform deposit impactor (MOUDI) measurements at 18 sites across North America. Size-resolved measurements of particulate SO42-, NO3-, NH4+, Na+, Cl-, Mg2+, Ca2+, and K+ are compared to CMAQ model output for discrete sampling periods between 2002 and 2005. The observation sites were predominantly in remote areas (e.g., National Parks) in the USA and Canada, and measurements were typically made for a period of roughly 1 month. For SO42- and NH4+, model performance was consistent across the USA and Canadian sites, with the model slightly overestimating the peak particle diameter and underestimating the peak particle concentration compared to the observations. Na+ and Mg2+ size distributions were generally well represented at coastal sites, indicating reasonable simulation of emissions from sea spray. CMAQ is able to simulate the displacement of Cl- in aged sea spray aerosol, though the extent of Cl- depletion relative to Na+ is often underpredicted. The model performance for NO3- exhibited much more site-to-site variability than that of SO42- and NH4+, with the model ranging from an underestimation to overestimation of both the peak diameter and peak particle concentration across the sites. Computing PM2.5 from the modeled size distribution parameters rather than by summing the masses in the Aitken and accumulation modes resulted in differences in daily averages of up to 1 μg m-3 (10 %), while the difference in seasonal and annual model performance compared to observations from the Interagency Monitoring of Protected Visual Environments (IMPROVE), Chemical Speciation Network (CSN), and Air Quality System (AQS) networks was very small. Two updates to the CMAQ aerosol model - changes to the assumed size and mode width of emitted particles and the implementation of gravitational settling - resulted in small improvements in

  18. Retrospection-Simulation-Revision: Approach to the Analysis of the Composition and Characteristics of Medical Waste at a Disaster Relief Site.

    PubMed

    Zhang, Li; Wu, Lihua; Tian, Feng; Wang, Zheng

    2016-01-01

    A large amount of medical waste is produced during disaster relief, posing a potential hazard to the habitat and the environment. A comprehensive understanding of the composition and characteristics of medical waste that requires management is one of the most basic steps in the development of a plan for medical waste management. Unfortunately, limited reliable information is available in the open literature on the characteristics of the medical waste that is generated at disaster relief sites. This paper discusses the analysis of the composition and characteristics of medical waste at a disaster relief site using the retrospection-simulation-revision method. For this study, we obtained 35 medical relief records of the Wenchuan Earthquake, Sichuan, May 2008 from a field cabin hospital. We first present a retrospective analysis of the relief medical records, and then, we simulate the medical waste generated in the affected areas. We ultimately determine the composition and characteristics of medical waste in the affected areas using untreated medical waste to revise the composition of the simulated medical waste. The results from 35 cases showed that the medical waste generated from disaster relief consists of the following: plastic (43.2%), biomass (26.3%), synthetic fiber (15.3%), rubber (6.6%), liquid (6.6%), inorganic salts (0.3%) and metals (1.7%). The bulk density of medical relief waste is 249 kg/m3, and the moisture content is 44.75%. The data should be provided to assist the collection, segregation, storage, transportation, disposal and contamination control of medical waste in affected areas. In this paper, we wish to introduce this research method of restoring the medical waste generated in disaster relief to readers and researchers. In addition, we hope more disaster relief agencies will become aware of the significance of medical case recording and storing. This may be very important for the environmental evaluation of medical waste in disaster areas, as

  19. Retrospection-Simulation-Revision: Approach to the Analysis of the Composition and Characteristics of Medical Waste at a Disaster Relief Site

    PubMed Central

    Zhang, Li; Wu, Lihua; Tian, Feng; Wang, Zheng

    2016-01-01

    A large amount of medical waste is produced during disaster relief, posing a potential hazard to the habitat and the environment. A comprehensive understanding of the composition and characteristics of medical waste that requires management is one of the most basic steps in the development of a plan for medical waste management. Unfortunately, limited reliable information is available in the open literature on the characteristics of the medical waste that is generated at disaster relief sites. This paper discusses the analysis of the composition and characteristics of medical waste at a disaster relief site using the retrospection-simulation-revision method. For this study, we obtained 35 medical relief records of the Wenchuan Earthquake, Sichuan, May 2008 from a field cabin hospital. We first present a retrospective analysis of the relief medical records, and then, we simulate the medical waste generated in the affected areas. We ultimately determine the composition and characteristics of medical waste in the affected areas using untreated medical waste to revise the composition of the simulated medical waste. The results from 35 cases showed that the medical waste generated from disaster relief consists of the following: plastic (43.2%), biomass (26.3%), synthetic fiber (15.3%), rubber (6.6%), liquid (6.6%), inorganic salts (0.3%) and metals (1.7%). The bulk density of medical relief waste is 249 kg/m3, and the moisture content is 44.75%. The data should be provided to assist the collection, segregation, storage, transportation, disposal and contamination control of medical waste in affected areas. In this paper, we wish to introduce this research method of restoring the medical waste generated in disaster relief to readers and researchers. In addition, we hope more disaster relief agencies will become aware of the significance of medical case recording and storing. This may be very important for the environmental evaluation of medical waste in disaster areas, as

  20. Impact of moisture source regions on the isotopic composition of precipitation events at high-mountain continental site Kasprowy Wierch, southern Poland

    NASA Astrophysics Data System (ADS)

    Rozanski, Kazimierz; Chmura, Lukasz; Dulinski, Marek

    2016-04-01

    Five-year record of deuterium and oxygen-18 isotope composition of precipitation events collected on top of the Kasprowy Wierch mountain (49° 14'N, 19° 59'E, 1989 m a.s.l.) located in north-western High Tatra mountain ridge, southern Poland, is presented and discussed. In total 670 precipitation samples have been collected and analysed. Stable isotope composition of the analysed precipitation events varied in a wide range, from -2.9 to -26.6‰ for δ18O and from -7 to -195 ‰ for δ2H. The local meteoric water line (LMWL) defined by single events data (δ2H=(7.86±0.05)δ18O+(12.9±0.6) deviate significantly from the analogous line defined by monthly composite precipitation data available for IAEA/GNIP station Krakow-Balice (50o04'N, 19o55'E, 220 m a.s.l.), located ca. 100 km north of Kasprowy Wierch ((δ2H=(7.82±0.11)δ18O+(6.9±1.1). While slopes of those two LMWLs are statistically indistinguishable, the intercept of Kasprowy Wierch line is almost two times higher that that characterizing Krakow monthly precipitation. This is well-documented effect associated with much higher elevation of Kasprowy Wierch sampling site when compared to Krakow. The isotope data for Kasprowy Wierch correlate significantly with air temperature, with the slope of the regression line being equal 0.35±0.02 ‰oC for δ18O, whereas no significant correlation with precipitation amount could be established. The impact of moisture source regions on the isotopic composition of precipitation events collected at Kasprowy Wierch site was analysed using HYSPLITE back trajectory model. Five-days back trajectories were calculated for all analysed precipitation events and seasonal maps of trajectory distribution were produced. They illustrate changes in the prevailing transport patterns of air masses bringing precipitation to the sampling site. Back trajectories for the events yielding extreme isotopic composition of precipitation collected at Kasprowy Wierch were analyzed in detail

  1. Chemical composition of the major components of PM in different sites at the Metropolitan Region of Chile

    NASA Astrophysics Data System (ADS)

    Reyes, F.; Castillo, M. A.; Rubio, M.; Gramsch, E.; Vasquez, Y.; Oyola, P.

    2013-05-01

    Santiago, Chile's capital is one of most polluted megacity (5.5 million of people) of the world. Currently, PM2.5 annual concentration is over 2.2 times the Chilean standard (20 μg/m3). Continuous measurements of non-refractory PM1.0 (sulfate, nitrate, chloride, ammonium and organics aerosols), black carbon, and PM2,5 mass concentration were determined using Aerosol Chemical Speciation Monitor (ACSM, Aerodyne Research, Inc), absorption coefficient monitor (SIMCA, Santiago University) and dustrack monitor (TSI Inc) in order to know the temporal variability of the major components of PM. The measurements were carried out at kerbside, urban background, industrial and mixed residential/industrial locations during year 2012 and -2013. Meteorological data (Relative Humidity, temperature, wind speed, wind direction and precipitations) were obtained from the air quality network operated by the environmental authority. The results show strong correlation with the metropolitan region major sources. Multiple regression analysis indicates that precipitations have a strong impact on PM1.0 soluble components; relative humidity has effects only on chloride, sulfate and black carbon. Chloride concentration decrease when temperature is increasing. The perceptual contribution of each component is similar among all sites. All sites shows that OA (Organics Aerosol) as the major constituent of PM1.0 (>50%), followed of nitrates (>13%). Sulfate could be used to differentiate the industrial site; due to there is a strong impact of SO2 emission. Combustion sources direct impact can be seen at BC contribution at industrial and kerbside site. Also, the OA/BC ratio shows slow value at kerbside (3.05) and industrial (3.26) site, and higher at urban background site (4.15). Aged organics aerosols are majority found at all sites (f43/f44 plot), indicating that regional background is strong in all results. These results will be compared with size distribution measurements available from previous

  2. Influence of human activity patterns, particle composition, and residential air exchange rates on modeled distributions of PM2.5 exposure compared with central-site monitoring data.

    PubMed

    Baxter, Lisa K; Burke, Janet; Lunden, Melissa; Turpin, Barbara J; Rich, David Q; Thevenet-Morrison, Kelly; Hodas, Natasha; Ökaynak, Halûk

    2013-01-01

    Central-site monitors do not account for factors such as outdoor-to-indoor transport and human activity patterns that influence personal exposures to ambient fine-particulate matter (PM(2.5)). We describe and compare different ambient PM(2.5) exposure estimation approaches that incorporate human activity patterns and time-resolved location-specific particle penetration and persistence indoors. Four approaches were used to estimate exposures to ambient PM(2.5) for application to the New Jersey Triggering of Myocardial Infarction Study. These include: Tier 1, central-site PM(2.5) mass; Tier 2A, the Stochastic Human Exposure and Dose Simulation (SHEDS) model using literature-based air exchange rates (AERs); Tier 2B, the Lawrence Berkeley National Laboratory (LBNL) Aerosol Penetration and Persistence (APP) and Infiltration models; and Tier 3, the SHEDS model where AERs were estimated using the LBNL Infiltration model. Mean exposure estimates from Tier 2A, 2B, and 3 exposure modeling approaches were lower than Tier 1 central-site PM(2.5) mass. Tier 2A estimates differed by season but not across the seven monitoring areas. Tier 2B and 3 geographical patterns appeared to be driven by AERs, while seasonal patterns appeared to be due to variations in PM composition and time activity patterns. These model results demonstrate heterogeneity in exposures that are not captured by the central-site monitor. PMID:23321856

  3. The effects of crushing speed on the energy-absorption capability of composite tubes

    NASA Technical Reports Server (NTRS)

    Farley, Gary L.

    1991-01-01

    The energy-absorption capability as a function of crushing speed was determined for Thornel 300-Fiberite 934 (Gr-E) and Kevlar-49-Fiberite 934 (K-E) composite material. Circular cross section tube specimens were crushed at speeds ranging from 0.01 to 12 m/sec. Ply orientations of the tube specimens were (0/ +/- theta)2 and (+/- theta)2 where theta = 15, 45, and 75 deg. Based upon the results of these tests, the energy-absorption capability of Gr-E and K-E was determined to be a function of crushing speed. The magnitude of the effects of crushing speed on energy-absorption capability was determined to be a function of the mechanisms that control the crushing process. The effects of crushing speed on the energy-absorption capability is related to whether the mechanical response of the crushing mechanism that controls the crushing process is a function of strain rate. Energy-absorption capability of Gr-E and K-E tubes ranged between 0 and 35 percent and 20 and 45 percent, respectively, depending upon ply orientation.

  4. Field study of the composition of greywater and comparison of microbiological indicators of water quality in on-site systems.

    PubMed

    Leonard, Margaret; Gilpin, Brent; Robson, Beth; Wall, Katrina

    2016-08-01

    Thirty on-site greywater systems were sampled to determine greywater characteristics and practices in the field. Kitchen greywater was present at eight sites and urine was included at seven sites. These non-traditional sources resulted in significantly higher concentrations of enterococci and 5-day biochemical oxygen demand (BOD5) in greywater. Even with the removal of these sources, the concentrations of microbial indicators indicated high levels of contamination could occur across all greywater sources, including "light" greywater. Using multiple microbial indicators showed that all samples had the potential for faecal contamination. Bacteroidales markers were confirmed in treated greywater and in each greywater source, highlighting the potential for human faecal contamination. Although Escherichia coli was absent in treated greywater recycled to the house, other microbial indicators were present; hence, caution is required in using E. coli concentrations as the sole indicator of microbiological water quality. High BOD5 or total suspended solid concentrations exceeded the levels recommended for effective disinfection. Subsurface irrigation, which is assumed to provide a five-log reduction in exposure, is a suitable reuse option for non-disinfected greywater. Only half the occupants had a good understanding of their greywater systems and 25 % of systems were poorly maintained. Elevated microbial indicator contamination of greywater sludge is a potential hazard during maintenance. PMID:27435622

  5. Study on the chemical composition features of Longquan celadon excavated from the Chuzhou site of Huai'an City in Jiangsu Province by EDXRF

    NASA Astrophysics Data System (ADS)

    Li, Li; Feng, Song-Lin; Feng, Xiang-Qian; Xu, Qing; Yan, Ling-Tong; Ma, Bo; Huo, Hua

    2011-07-01

    A mass of Longquan celadon shards were excavated from the Chuzhou site of Huai'an City in Jiangsu Province, China. These celadon shards were fired during the period of the Late Yuan Dynasty to the Tianshun era of the Ming Dynasty, as identified by archaeologists at Nanjing Museum. In order to research the chemical composition features of this ancient celadon porcelain, energy dispersive X-ray fluorescence (EDXRF) for non-destructive analysis was used to determine the chemical composition of the porcelain body and glaze in these shards. The results indicate that Ti and Fe in the body of Longquan celadon are characteristic elements which can distinguish porcelain produced during the Late Yuan Dynasty from those produced in the Ming Dynasties. The results of the principal component analysis (PCA) show that different body and glaze raw materials were used for the production of porcelain in different periods and the raw materials of the body and glaze are also different for various vessel shapes. The chemical compositions in the porcelain body of civilian ware are slightly different. The imperial and civilian Longquan celadon porcelains produced during the Hongwu era to the Tianshun era of the Ming Dynasty are distinguishable by the MnO, Fe2O3, Rb2O and SrO content in their porcelain glaze.

  6. Sampling errors associated with soil composites used to estimate mean Ra-226 concentrations at an UMTRA remedial-action site

    SciTech Connect

    Gilbert, R.O.; Baker, K.R.; Nelson, R.A.; Miller, R.H.; Miller, M.L.

    1987-07-01

    The decision whether to take additional remedial action (removal of soil) from regions contaminated by uranium mill tailings involves collecting 20 plugs of soil from each 10-m by 10-m plot in the region and analyzing a 500-g portion of the mixed soil for /sup 226/Ra. A soil sampling study was conducted in the windblown mill-tailings flood plain area at Shiprock, New Mexico, to evaluate whether reducing the number of soil plugs to 9 would have any appreciable impact on remedial-action decisions. The results of the Shiprock study are described and used in this paper to develop a simple model of the standard deviation of /sup 226/Ra measurements on composite samples formed from 21 or fewer plugs. This model is used to predict as a function of the number of soil plugs per composite, the percent accuracy with which the mean /sup 226/Ra concentration in surface soil can be estimated, and the probability of making incorrect remedial action decisions on the basis of statistical tests. 8 refs., 15 figs., 9 tabs.

  7. Springtime carbon emission episodes at the Gosan background site revealed by total carbon, stable carbon isotopic composition, and thermal characteristics of carbonaceous particles

    NASA Astrophysics Data System (ADS)

    Jung, J.; Kawamura, K.

    2011-11-01

    In order to investigate the emission of carbonaceous aerosols at the Gosan background super-site (33.17° N, 126.10° E) in East Asia, total suspended particles (TSP) were collected during spring of 2007 and 2008 and analyzed for particulate organic carbon, elemental carbon, total carbon (TC), total nitrogen (TN), and stable carbon isotopic composition (δ13C) of TC. The stable carbon isotopic composition of TC (δ13CTC) was found to be lowest during pollen emission episodes (range: -26.2‰ to -23.5‰, avg. -25.2 ± 0.9‰), approaching those of the airborne pollen (-28.0‰) collected at the Gosan site. Based on a carbon isotope mass balance equation, we found that ~42% of TC in the TSP samples during the pollen episodes was attributed to airborne pollen from Japanese cedar trees planted around tangerine farms in Jeju Island. A negative correlation between the citric acid-carbon/TC ratios and δ13CTC was obtained during the pollen episodes. These results suggest that citric acid emitted from tangerine fruit may be adsorbed on the airborne pollen and then transported to the Gosan site. Thermal evolution patterns of organic carbon during the pollen episodes were characterized by high OC evolution in the OC2 temperature step (450 °C). Since thermal evolution patterns of organic aerosols are highly influenced by their molecular weight, they can be used as additional information on the formation of secondary organic aerosols and the effect of aging of organic aerosols during the long-range atmospheric transport and sources of organic aerosols.

  8. Springtime carbon episodes at Gosan background site revealed by total carbon, stable carbon isotopic composition, and thermal characteristics of carbonaceous particles

    NASA Astrophysics Data System (ADS)

    Jung, J.; Kawamura, K.

    2011-05-01

    In order to investigate the carbon episodes at Gosan background super-site (33.17° N, 126.10° E) in East Asia during spring of 2007 and 2008, total suspended particles (TSP) were collected and analyzed for particulate organic carbon, elemental carbon, total carbon (TC), total nitrogen (TN), and stable carbon isotopic composition (δ13C) of TC. The carbon episodes at the Gosan site were categorized as long-range transported anthropogenic pollutant (LTP) from Asian continent, Asian dust (AD) accompanying with LTP, and local pollen episodes. The stable carbon isotopic composition of TC (δ13CTC) was found to be lowest during the pollen episodes (range: -26.2 ‰ to -23.5 ‰, avg.: -25.2 ± 0.9 ‰), followed by the LTP episodes (range: -23.5 ‰ to -23.0 ‰, avg.: -23.3 ± 0.3 ‰) and the AD episodes (range: -23.3 to -20.4 %, avg.: -21.8 ± 2.0 ‰). The δ13CTC of the airborne pollens (-28.0 ‰) collected at the Gosan site showed value similar to that of tangerine fruit (-28.1 ‰) produced from Jeju Island. Based on the carbon isotope mass balance equation and the TN and TC regression approach, we found that ∼40-45 % of TC in the TSP samples during the pollen episodes was attributed to airborne pollens from Japanese cedar trees planted around tangerine farms in Jeju Island. The δ13C of citric acid in the airborne pollens (-26.3 ‰) collected at the Gosan site was similar to that in tangerine fruit (-27.4 ‰). The negative correlation between the citric acid-carbon/TC ratios and δ13CTC were obtained during the pollen episodes. These results suggest that citric acid emitted from tangerine fruit may be adsorbed on the airborne pollens and then transported to the Gosan site. Based on the thermal evolution pattern of organic aerosols during the carbon episodes, we found that organic aerosols originated from East China are more volatile on heating and are more likely to form pyrolized organic carbon than the pollen-enriched organic aerosols and organic

  9. Chemical composition, sources and evolution processes of aerosol at an urban site in Yangtze River Delta, China during wintertime

    NASA Astrophysics Data System (ADS)

    Zhang, Yunjiang; Tang, Lili; Yu, Hongxia; Wang, Zhuang; Sun, Yele; Qin, Wei; Chen, Wentai; Chen, Changhong; Ding, Aijun; Wu, Jing; Ge, Shun; Chen, Cheng; Zhou, Hong-cang

    2015-12-01

    To investigate the composition, sources and evolution processes of submicron aerosol during wintertime, a field experiment was conducted during December 1-31, 2013 in urban Nanjing, a megacity in Yangtze River Delta of China. Non-refractory submicron aerosol (NR-PM1) species were measured with an Aerodyne Aerosol Chemical Speciation Monitor. NR-PM1 is dominated by secondary inorganic aerosol (55%) and organic aerosol (OA, 42%) during haze periods. Six OA components were identified by positive matrix factorization of the OA mass spectra. The hydrocarbon-like OA and cooking-related OA represent the local traffic and cooking sources, respectively. A highly oxidized factor related to biomass burning OA accounted for 15% of the total OA mass during haze periods. Three types of oxygenated OA (OOA), i.e., a less-oxidized OOA (LO-OOA), a more-oxidized OOA (MO-OOA), and a low-volatility OOA (LV-OOA), were identified. LO-OOA is likely associated with fresh urban secondary OA. MO-OOA likely represents photochemical products showing a similar diurnal cycle to nitrate with a pronounced noon peak. LV-OOA appears to be a more oxidized factor with a pronounced noon peak. The OA composition is dominated by secondary species, especially during haze events. LO-OOA, MO-OOA and LV-OOA on average account for 11%, (18%), 24% (21%) and 23% (18%) of the total OA mass for the haze (clean) periods respectively. Analysis of meteorological influence suggested that regional transport from the northern and southeastern areas of the city is responsible for large secondary and low-volatility aerosol formation.

  10. Chemical Composition, Seasonal Variation and Size distribution of Atmospheric Aerosols at an Alpine Site in Guanzhong Plain, China

    NASA Astrophysics Data System (ADS)

    Li, J.

    2015-12-01

    PM10 and size-segregated aerosol samples were collected at Mt. Hua (2065 a.s.m) in central China, and determined for carbonaceous fraction, ions and organic composition. The concentration of most chemical compositions in summer are lower than those in winter, due to decreased emissions of biomass and coal burning for house heating. High temperature and relative humidity (RH) conditions are favorable for secondary aerosol formation, resulting in higher concentrations of SO42- and NH4+ in summer. Non-dehydrated sugars are increased in summer because of the enhanced metabolism. Carbon preference index results indicate that n-alkanes at Mt. Hua are derived mostly by plant wax. Low Benzo(a)pyrene/Benzo(a)pyrene ratios indicate that mountain aerosols are more aged. Concentrations of biogenic (BSOA, the isoprene/pinene/caryophyllene oxidation products) and anthropogenic (ASOA, mainly aromatic acids) SOA positively correlated with temperature . However, a decreasing trend of BSOA concentration with an increase in RH was observed during the sampling period, although a clear trend between ASOA and RH was not found. Based on the AIM Model calculation, we found that during the sampling period an increase in RH resulted in a decrease in the aerosol acidity and thus reduced the effect of acid-catalysis on BSOA formation. Size distributions of K+ and NH4+ present as an accumulation mode, in contrast to Ca2+ and Mg2+, which are mainly existed in coarse particles. SO42- and NO3- show a bimodal pattern. Dehydrated sugars, fossil fuel derived n-alkanes and PAHs presented unimode size distribution, whereas non-dehydrated sugars and plant wax derived n-alkanes showed bimodal pattern. Most of the determined BSOA are formed in the aerosol phase and enriched in the fine mode except for cis-pinonic acid, which is formed in the gas phase and subsequently partitioned into aerosol phase and thus presents a bimodal pattern with a major peak in the coarse mode.

  11. Geochemical Analyses of Surface and Shallow Gas Flux and Composition Over a Proposed Carbon Sequestration Site in Eastern Kentucky

    SciTech Connect

    Thomas Parris; Michael Solis; Kathryn Takacs

    2009-12-31

    Using soil gas chemistry to detect leakage from underground reservoirs (i.e. microseepage) requires that the natural range of soil gas flux and chemistry be fully characterized. To meet this need, soil gas flux (CO{sub 2}, CH{sub 4}) and the bulk (CO{sub 2}, CH{sub 4}) and isotopic chemistry ({delta}{sup 13}C-CO2) of shallow soil gases (<1 m, 3.3 ft) were measured at 25 locations distributed among two active oil and gas fields, an active strip mine, and a relatively undisturbed research forest in eastern Kentucky. The measurements apportion the biologic, atmospheric, and geologic influences on soil gas composition under varying degrees of human surface disturbance. The measurements also highlight potential challenges in using soil gas chemistry as a monitoring tool where the surface cover consists of reclaimed mine land or is underlain by shallow coals. For example, enrichment of ({delta}{sup 13}C-CO2) and high CH{sub 4} concentrations in soils have been historically used as indicators of microseepage, but in the reclaimed mine lands similar soil chemistry characteristics likely result from dissolution of carbonate cement in siliciclastic clasts having {delta}{sup 13}C values close to 0{per_thousand} and degassing of coal fragments. The gases accumulate in the reclaimed mine land soils because intense compaction reduces soil permeability, thereby impeding equilibration with the atmosphere. Consequently, the reclaimed mine lands provide a false microseepage anomaly. Further potential challenges arise from low permeability zones associated with compacted soils in reclaimed mine lands and shallow coals in undisturbed areas that might impede upward gas migration. To investigate the effect of these materials on gas migration and composition, four 10 m (33 ft) deep monitoring wells were drilled in reclaimed mine material and in undisturbed soils with and without coals. The wells, configured with sampling zones at discrete intervals, show the persistence of some of the

  12. Site-Selective Modification of Cellulose Nanocrystals with Isophorone Diisocyanate and Formation of Polyurethane-CNC Composites.

    PubMed

    Girouard, Natalie M; Xu, Shanhong; Schueneman, Gregory T; Shofner, Meisha L; Meredith, J Carson

    2016-01-20

    The unequal reactivity of the two isocyanate groups in an isophorone diisocyante (IPDI) monomer was exploited to yield modified cellulose nanocrystals (CNCs) with both urethane and isocyanate functionality. The chemical functionality of the modified CNCs was verified with ATR-FTIR analysis and elemental analysis. The selectivity for the secondary isocyanate group using dibutyl tin dilaurate (DBTDL) as the reaction catalyst was confirmed with (13)C NMR. The modified CNCs showed improvements in the onset of thermal degradation by 35 °C compared to the unmodified CNCs. Polyurethane composites based on IPDI and a trifunctional polyether alcohol were synthesized using unmodified (um-CNC) and modified CNCs (m-CNC). The degree of nanoparticle dispersion was qualitatively assessed with polarized optical microscopy. It was found that the modification step facilitated superior nanoparticle dispersion compared to the um-CNCs, which resulted in increases in the tensile strength and work of fracture of over 200% compared to the neat matrix without degradation of elongation at break. PMID:26713564

  13. Depth, soil type, water table, and site effects on microbial community composition in sediments of pesticide-contaminated aquifer.

    PubMed

    Mattsson, Marja K; Liu, Xinxin; Yu, Dan; Kontro, Merja H

    2015-07-01

    Microbial community compositions in pesticide-contaminated aquifers have not been studied, although such information is important for remediation and maintaining freshwater sources clean under changing climate. Therefore, phospholipid (PLFAs), glycolipid (GLFAs), and neutral lipid (NLFAs) fatty acids were determined from sand and clay sediments at depths of 0.3-24.8 m, all contaminated with triazines and dichlobenil/2,6-dichlorobenzamide. The portion of fungi and Gram-negative bacteria at 0.3 m was greater than at 0.8 m, where the percentage of Gram-positive bacteria, actinobacteria, and sulfate-reducing bacteria (SRB) increased. In deeper sediments, microbial biomass, activity, and diversity decreased. Clay sediments seemed to serve as a reservoir for slow pesticide elution to groundwater, and their biomarker portion for all bacteria except actinobacteria was greater than in sand sediments. The slow pesticide dissipation seemed to occur in the main groundwater flow zone, resulting in nitrogen release simultaneously with organic matter elution from gardening and bank filtration. As a result, microbial biomass, activity, and diversity were increased. This shift in conditions towards that in surface soil may be appropriate for enhanced natural attenuation of pesticides in groundwater sources. PMID:25703619

  14. Pore-lining composition and capillary breakthrough pressure of mudstone caprocks : sealing efficiency at geologic CO2 storage sites.

    SciTech Connect

    Heath, Jason E.; Nemer, Martin B.; McPherson, Brian J. O. L.; Dewers, Thomas A.; Kotula, Paul Gabriel

    2010-12-01

    Subsurface containment of CO2 is predicated on effective caprock sealing. Many previous studies have relied on macroscopic measurements of capillary breakthrough pressure and other petrophysical properties without direct examination of solid phases that line pore networks and directly contact fluids. However, pore-lining phases strongly contribute to sealing behavior through interfacial interactions among CO2, brine, and the mineral or non-mineral phases. Our high resolution (i.e., sub-micron) examination of the composition of pore-lining phases of several continental and marine mudstones indicates that sealing efficiency (i.e., breakthrough pressure) is governed by pore shapes and pore-lining phases that are not identifiable except through direct characterization of pores. Bulk X-ray diffraction data does not indicate which phases line the pores and may be especially lacking for mudstones with organic material. Organics can line pores and may represent once-mobile phases that modify the wettability of an originally clay-lined pore network. For shallow formations (i.e., < {approx}800 m depth), interfacial tension and contact angles result in breakthrough pressures that may be as high as those needed to fracture the rock - thus, in the absence of fractures, capillary sealing efficiency is indicated. Deeper seals have poorer capillary sealing if mica-like wetting dominates the wettability. We thank the U.S. Department of Energy's National Energy Technology Laboratory and the Office of Basic Energy Sciences, and the Southeast and Southwest Carbon Sequestration Partnerships for supporting this work.

  15. Pore-lining composition and capillary breakthrough pressure of mudstone caprocks : sealing efficiency of geologic CO2 storage sites.

    SciTech Connect

    Petrusak, Robin; Heath, Jason E.; McPherson, Brian J. O. L.; Dewers, Thomas A.; Kotula, Paul Gabriel

    2010-08-01

    Subsurface containment of CO2 is predicated on effective caprock sealing. Many previous studies have relied on macroscopic measurements of capillary breakthrough pressure and other petrophysical properties without direct examination of solid phases that line pore networks and directly contact fluids. However, pore-lining phases strongly contribute to sealing behavior through interfacial interactions among CO2, brine, and the mineral or non-mineral phases. Our high resolution (i.e., sub-micron) examination of the composition of pore-lining phases of several continental and marine mudstones indicates that sealing efficiency (i.e., breakthrough pressure) is governed by pore shapes and pore-lining phases that are not identifiable except through direct characterization of pores. Bulk X-ray diffraction data does not indicate which phases line the pores and may be especially lacking for mudstones with organic material. Organics can line pores and may represent once-mobile phases that modify the wettability of an originally clay-lined pore network. For shallow formations (i.e., < {approx}800 m depth), interfacial tension and contact angles result in breakthrough pressures that may be as high as those needed to fracture the rock - thus, in the absence of fractures, capillary sealing efficiency is indicated. Deeper seals have poorer capillary sealing if mica-like wetting dominates the wettability.

  16. In vitro toxicity of particulate matter (PM) collected at different sites in the Netherlands is associated with PM composition, size fraction and oxidative potential - the RAPTES project

    PubMed Central

    2011-01-01

    Background Ambient particulate matter (PM) exposure is associated with respiratory and cardiovascular morbidity and mortality. To what extent such effects are different for PM obtained from different sources or locations is still unclear. This study investigated the in vitro toxicity of ambient PM collected at different sites in the Netherlands in relation to PM composition and oxidative potential. Method PM was sampled at eight sites: three traffic sites, an underground train station, as well as a harbor, farm, steelworks, and urban background location. Coarse (2.5-10 μm), fine (< 2.5 μm) and quasi ultrafine PM (qUF; < 0.18 μm) were sampled at each site. Murine macrophages (RAW 264.7 cells) were exposed to increasing concentrations of PM from these sites (6.25-12.5-25-50-100 μg/ml; corresponding to 3.68-58.8 μg/cm2). Following overnight incubation, MTT-reduction activity (a measure of metabolic activity) and the release of pro-inflammatory markers (Tumor Necrosis Factor-alpha, TNF-α; Interleukin-6, IL-6; Macrophage Inflammatory Protein-2, MIP-2) were measured. The oxidative potential and the endotoxin content of each PM sample were determined in a DTT- and LAL-assay respectively. Multiple linear regression was used to assess the relationship between the cellular responses and PM characteristics: concentration, site, size fraction, oxidative potential and endotoxin content. Results Most PM samples induced a concentration-dependent decrease in MTT-reduction activity and an increase in pro-inflammatory markers with the exception of the urban background and stop & go traffic samples. Fine and qUF samples of traffic locations, characterized by a high concentration of elemental and organic carbon, induced the highest pro-inflammatory activity. The pro-inflammatory response to coarse samples was associated with the endotoxin level, which was found to increase dramatically during a three-day sample concentration procedure in the laboratory. The underground samples

  17. Influence of substrate tectonic heritage on the evolution of composite volcanoes: Predicting sites of flank eruption, lateral collapse, and erosion

    NASA Astrophysics Data System (ADS)

    Tibaldi, Alessandro; Corazzato, Claudia; Kozhurin, Andrey; Lagmay, Alfredo F. M.; Pasquarè, Federico A.; Ponomareva, Vera V.; Rust, Derek; Tormey, Daniel; Vezzoli, Luigina

    2008-04-01

    This paper aims to aid understanding of the complicated interplay between construction and destruction of volcanoes, with an emphasis on the role of substrate tectonic heritage in controlling magma conduit geometry, lateral collapse, landslides, and preferential erosion pathways. The influence of basement structure on the development of six composite volcanoes located in different geodynamic/geological environments is described: Stromboli (Italy), in an island arc extensional tectonic setting, Ollagüe (Bolivia-Chile) in a cordilleran extensional setting, Kizimen (Russia) in a transtensional setting, Pinatubo (Philippines) in a transcurrent setting, Planchon (Chile) in a compressional cordilleran setting, and Mt. Etna (Italy) in a complex tectonic boundary setting. Analogue and numerical modelling results are used to enhance understanding of processes exemplified by these volcanic centres. We provide a comprehensive overview of this topic by considering a great deal of relevant, recently published studies and combine these with the presentation of new results, in order to contribute to the discussion on substrate tectonics and its control on volcano evolution. The results show that magma conduits in volcanic rift zones can be geometrically controlled by the regional tectonic stress field. Rift zones produce a lateral magma push that controls the direction of lateral collapse and can also trigger collapse. Once lateral collapse occurs, the resulting debuttressing produces a reorganization of the shallow-level magma migration pathways towards the collapse depression. Subsequent landslides and erosion tend to localize along rift zones. If a zone of weakness underlies a volcano, long-term creep can occur, deforming a large sector of the cone. This deformation can trigger landslides that propagate along the destabilized flank axis. In the absence of a rift zone, normal and transcurrent faults propagating from the substrate through the volcano can induce flank

  18. A study of summer and winter highly time-resolved submicron aerosol composition measured at a suburban site in Prague

    NASA Astrophysics Data System (ADS)

    Kubelová, Lucie; Vodička, Petr; Schwarz, Jaroslav; Cusack, Michael; Makeš, Otakar; Ondráček, Jakub; Ždímal, Vladimír

    2015-10-01

    The variability of aerosol chemical composition and the impact of the origin of respective air masses were studied in high time resolution for selected periods of high and low levels of aerosol burden at a suburban station in Prague-Suchdol, Czech Republic in summer and winter. Ambient aerosol measurements were performed using the compact-Time of Flight-Aerosol Mass Spectrometer (c-ToF-AMS) and variations in concentration of the main species are discussed. The average mass concentrations for the main species were (summer; winter): organic matter (4.2 μg/m3; 8.4 μg/m3), SO42- (2.0 μg/m3; 4.4 μg/m3), NH4+ (1.2 μg/m3; 2.8 μg/m3), NO3- (0.8 μg/m3; 5.4 μg/m3) and Cl- (0.1 μg/m3; 0.23 μg/m3). We found an inverse relationship between non-refractory submicron particulate matter (NR-PM1) levels and the boundary layer height, mainly in winter. Furthermore, levels of pollution were influenced by the air mass origin, where cleaner maritime air masses resulted in lower aerosol levels compared to those of continental origin. Analysis of the diurnal variation of NR-PM1 showed minimum concentrations in the afternoon caused by dilution as a result of an increase in the boundary layer height. Most maximum concentrations of the main species occurred in the morning or night except sulphate which had a midday maximum, probably due to downdraft from upper boundary layer air and photochemical formation in the afternoon.

  19. Strong lithium polysulfide chemisorption on electroactive sites of nitrogen-doped carbon composites for high-performance lithium-sulfur battery cathodes.

    PubMed

    Song, Jiangxuan; Gordin, Mikhail L; Xu, Terrence; Chen, Shuru; Yu, Zhaoxin; Sohn, Hiesang; Lu, Jun; Ren, Yang; Duan, Yuhua; Wang, Donghai

    2015-03-27

    Despite the high theoretical capacity of lithium-sulfur batteries, their practical applications are severely hindered by a fast capacity decay, stemming from the dissolution and diffusion of lithium polysulfides in the electrolyte. A novel functional carbon composite (carbon-nanotube-interpenetrated mesoporous nitrogen-doped carbon spheres, MNCS/CNT), which can strongly adsorb lithium polysulfides, is now reported to act as a sulfur host. The nitrogen functional groups of this composite enable the effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to a much improved electrochemical performance (1200 mAh g(-1) after 200 cycles). The enhancement in adsorption can be attributed to the chemical bonding of lithium ions by nitrogen functional groups in the MNCS/CNT framework. Furthermore, the micrometer-sized spherical structure of the material yields a high areal capacity (ca. 6 mAh cm(-2)) with a high sulfur loading of approximately 5 mg cm(-2), which is ideal for practical applications of the lithium-sulfur batteries. PMID:25663183

  20. Species composition of by-catch from milkfish (Chanos chanos) fry fishery in selected sites in the Philippines as determined by DNA barcodes.

    PubMed

    Asis, Angelli Marie Jacynth M; Destura, Irma; Santos, Mudjekeewis D

    2016-05-01

    Milkfish fry fishery, an important industry in the Philippines, uses non-selective fishing gears and push nets in coastal areas which lead to the capture of other non-targeted juvenile aquatic species. Unfortunately, information on the amount and the identity of by-catch species is lacking thus the extent of impact of the fry fishery is not known. In this study, the species composition of milkfish fry fishery by-catch sampled from selected coastal areas that are known to be fry collection sites in the country were identified and assessed through the use of DNA barcoding. Analyses revealed that by-catch fish species of the milkfish fry industry included Black Tiger shrimp (Peneaus monodon), Tarpon (Megalops cyprinoides), Glass perchlets (Ambasis gymnocephalus and Ambasis buruensis), Ladyfish (Elops hawaiensis), Snapper (Lutjanus fulviflamma), Cardinal fishes (Apogon hyalosoma and Sphaeramia orbicularis), Whipfin siver biddy (Gerres filamentosus), Mullet (Liza sp.), Anchovy (Encrasicholina heteroloba), and Tiger perch (Terapon jarbua), almost all of which are potential marketable food fish and culture species. The results of the study provide preliminary information, as well as awareness, on the species composition of milkfish fry by-catch. PMID:25329278

  1. Strong Lithium Polysulfide Chemisorption on Electroactive Sites of Nitrogen-Doped Carbon Composites For High-Performance Lithium-Sulfur Battery Cathodes

    SciTech Connect

    Song, Jiangxuan; Gordin, Mikhail L.; Xu, Terrence; Chen, Shuru; Yu, Zhaoxin; Sohn, Hiesang; Lu, Jun; Ren, Yang; Duan, Yuhua; Wang, Donghai

    2015-03-27

    Despite the high theoretical capacity of lithium–sulfur batteries, their practical applications are severely hindered by a fast capacity decay, stemming from the dissolution and diffusion of lithium polysulfides in the electrolyte. A novel functional carbon composite (carbon-nanotube-interpenetrated mesoporous nitrogen-doped carbon spheres, MNCS/CNT), which can strongly adsorb lithium polysulfides, is now reported to act as a sulfur host. The nitrogen functional groups of this composite enable the effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to a much improved electrochemical performance (1200 mAhg-1after 200 cycles). The enhancement in adsorption can be attributed to the chemical bonding of lithium ions by nitrogen functional groups in the MNCS/CNT framework. Furthermore, the micrometer-sized spherical structure of the material yields a high areal capacity (ca.6 mAhcm-2) with a high sulfur loading of approximately 5 mgcm-2, which is ideal for practical applications of the lithium–sulfur batteries.

  2. Chemical composition and thermal stability of GaAs oxides grown by AFM anodic oxidation for site-controlled growth of InAs quantum dots

    NASA Astrophysics Data System (ADS)

    Cha, K. M.; Shibata, K.; Horiuchi, I.; Kamiko, M.; Yamamoto, R.; Hirakawa, K.

    2011-12-01

    We have fabricated GaAs oxides by using atomic force microscope (AFM)-assisted anodic oxidation at various bias voltages, Vox, and studied their chemical compositions and thermal stabilities. The oxides grown at bias voltages less than 30 V desorbed after standard thermal cleaning in molecular beam epitaxy, while the oxide patterns fabricated at Vox≥40 V survived on the surface. We have further investigated the chemical composition of the oxides by X-ray photoemission spectroscopy. It has been found that the AFM oxides grown at Vox˜10 V predominantly consist of Ga2O and GaO, whereas those grown at Vox˜50 V contain a Ga2O3-component. This result indicates that the better thermal stability of AFM oxides grown at Vox≥40 V can be attributed to the formation of Ga2O3. We grew a GaAs buffer layer on the oxide nanomasks and obtained nanoholes. After supplying InAs, selective dot nucleation took place in the nanoholes, resulting in successful formation of site-controlled QDs.

  3. Changes in the Cytoplasmic Composition of Amino Acids and Proteins Observed in Staphylococcus aureus during Growth under Variable Growth Conditions Representative of the Human Wound Site

    PubMed Central

    Alreshidi, Mousa M.; Dunstan, R. Hugh; Gottfries, Johan; Macdonald, Margaret M.; Crompton, Marcus J.; Ang, Ching-Seng; Williamson, Nicholas A.; Roberts, Tim K.

    2016-01-01

    Staphylococcus aureus is an opportunistic pathogen responsible for a high proportion of nosocomial infections. This study was conducted to assess the bacterial responses in the cytoplasmic composition of amino acids and ribosomal proteins under various environmental conditions designed to mimic those on the human skin or within a wound site: pH6-8, temperature 35–37°C, and additional 0–5% NaCl. It was found that each set of environmental conditions elicited substantial adjustments in cytoplasmic levels of glutamic acid, aspartic acid, proline, alanine and glycine (P< 0.05). These alterations generated characteristic amino acid profiles assessed by principle component analysis (PCA). Substantial alterations in cytoplasmic amino acid and protein composition occurred during growth under conditions of higher salinity stress implemented via additional levels of NaCl in the growth medium. The cells responded to additional NaCl at pH 6 by reducing levels of ribosomal proteins, whereas at pH 8 there was an upregulation of ribosomal proteins compared with the reference control. The levels of two ribosomal proteins, L32 and S19, remained constant across all experimental conditions. The data supported the hypothesis that the bacterium was continually responding to the dynamic environment by modifying the proteome and optimising metabolic homeostasis. PMID:27442022

  4. Strong Lithium Polysulfide Chemisorption on Electroactive Sites of Nitrogen-Doped Carbon Composites For High-Performance Lithium–Sulfur Battery Cathodes

    SciTech Connect

    Song, Jiangxuan; Gordin, Mikhail; Xu, Terrence; Chen, Shuru; Yu, Zhaoxin; Sohn, Hiesang; Lu, Jun; Ren, Yang; Duan, Yuhua; wang, Donghai

    2015-03-27

    Despite the high theoretical capacity of lithium–sulfur batteries, their practical applications are severely hindered by a fast capacity decay, stemming from the dissolution and diffusion of lithium polysulfides in the electrolyte. A novel functional carbon composite (carbon-nanotube-interpenetrated mesoporous nitrogen-doped carbon spheres, MNCS/CNT), which can strongly adsorb lithium polysulfides, is now reported to act as a sulfur host. The nitrogen functional groups of this composite enable the effective trapping of lithium polysulfides on electroactive sites within the cathode, leading to a much improved electrochemical performance (1200 mAh g-1 after 200 cycles). The enhancement in adsorption can be attributed to the chemical bonding of lithium ions by nitrogen functional groups in the MNCS/CNT framework. Furthermore, the micrometer-sized spherical structure of the material yields a high areal capacity (ca. 6 mAh cm-2) with a high sulfur loading of approximately 5 mg cm-2, which is ideal for practical applications of the lithium–sulfur batteries.

  5. Outdoor and indoor aerosol size, number, mass and compositional dynamics at an urban background site during warm season

    NASA Astrophysics Data System (ADS)

    Talbot, N.; Kubelova, L.; Makes, O.; Cusack, M.; Ondracek, J.; Vodička, P.; Schwarz, J.; Zdimal, V.

    2016-04-01

    This paper describes the use of a unique valve switching system that allowed for high temporal resolution indoor and outdoor data to be collected concurrently from online C-ToF-AMS, SMPS and OC/EC, and offline BLPI measurements. The results reveal near real-time dynamic aerosol behaviour along a migration path from an outdoor to indoor environment. An outdoor reduction in NR-PM1 mass concentration occurred daily from AM (06:00-12:00) to PM (12:00-18:00). SO4 (26%-37%) [AM/PM] increased proportionally during afternoons at the expense of NO3 (18%-7%). The influences of mixing height, temperature and solar radiation were considered against the mean mass concentration loss for each species. Losses were then calculated according to species via a basic input/output model. NO3 lost the most mass during afternoon periods, which we attribute to the accelerated dissociation of NH4NO3 through increasing temperature and decreasing relative humidity. Indoor/outdoor (I/O) ratios varied from 0.46 for <40 nm to 0.65 for >100 nm. These ratios were calculated using average SMPS PNC measurements over the full campaign and corroborated using a novel technique of calculating I/O penetration ratios through the indoor migration of particles during a new particle formation event. This ratio was then used to observe changes in indoor composition relative to those outdoors. Indoor sampling was carried out in an undisturbed room with no known sources. Indoor concentrations were found to be proportional to those outdoors, with organic matter [2.7 μg/m3] and SO4 [1.7 μg/m3] being the most prominent species. These results are indicative of fairly rapid aerosol penetration, a source-free indoor environment and small afternoon I/O temperature gradients. Fine fraction NO3 was observed indoors in both real-time AMS PM1 and off-line BLPI measurements. Greater mass concentration losses were observed from filter measurements, highlighting an important time dependency factor when investigating semi

  6. Uranium-series disequilibrium in ground water and core composite samples from the San Juan Basin and Copper Mountain research sites

    SciTech Connect

    Osmond, J.K.; Cowart, J.B.

    1981-09-01

    The study of the patterns of /sup 238/U, /sup 234/U, and /sup 230/Th disequilibrium in two secondary uranium deposits shows that, on a 10/sup 4/ to 10/sup 5/ year time scale, considerable movement of the uranium has occurred. The deposit at the San Juan Basin Research Site is classified as a tabular ore body, and that at the Copper Mountain Research Site as a residual deposit; yet both can be recognized as having disequilibrium sectors consistent with a general model developed to explain roll-front dynamics. The disequilibrium patterns at the two deposits were studied in two ways: core composite samples, leached of their labile uranium and daughters; and ground water samples from the associated aquifer. In general, the core data and the water data are consistent. The uranium in the residual Copper Mountain deposits appears to be more mobile than does the ore of the San Juan Basin deposit. The ground water at Copper Mountain appears to be moving the uranium southward.

  7. PM chemical composition and oxidative potential of the soluble fraction of particles at two sites in the urban area of Milan, Northern Italy

    NASA Astrophysics Data System (ADS)

    Perrone, Maria Grazia; Zhou, Jun; Malandrino, Mery; Sangiorgi, Giorgia; Rizzi, Cristiana; Ferrero, Luca; Dommen, Josef; Bolzacchini, Ezio

    2016-03-01

    Recent epidemiological evidence support the hypothesis that health effects from inhalation of air particles are governed by more than just particle mass, since specific chemical components have been identified as important contributors to mortality and hospitality admissions. We studied the chemical composition and the oxidative potential (OP) of total suspended particle (TSP) samples from Milan at two sites with different traffic loads: a site in the low emission zone (LEZ) and a traffic site (TR) outside. Two a-cellular assays; dithiothreitol (OPDTT) and 2‧,7' dichlorofluorescin (OPDCFH) were used to characterize the OP of the soluble fraction of particles. TSP samples from LEZ showed significantly lower concentrations of traffic-related chemical components compared to TR. The decrease in the concentrations from TR to LEZ was maximum for EC, with a LEZ/TR ratio of 0.64 (±0.18), and a significant reduction (p < 0.01) was also observed for PAHs (LEZ/TR = 0.73 ± 0.16), elements (Mn, Cu, Zn, Cd, Pb: LEZ/TR ranged between 0.64 and 0.82), OC (LEZ/TR = 0.85 ± 0.12) and NH4+ (LEZ/TR = 0.92 ± 0.07). OP measures, expressed as OP/m3 or OP/mg, were comparable between sites both for OPDTT and OPDCFH, thus not showing any significant impact of local traffic on OP values at sites. OPDTT and OPDCFH showed contrasting seasonal and daily trends, indicating that the two a-cellular assays gave complementary information on the OP of particles in Milan. The two OP assays resulted to be sensitive to different chemical properties of PM samples. OPDTT correlated positively only with Global Radiation (Spearman's rs = 0.38, p < 0.05), which could be considered as a proxy for high concentrations of secondary oxidizing organics, while OPDCFH was related to various PM chemical species, mainly correlated with total mass (rs = 0.65; p < 0.01), elements (e.g. Zn, rs = 0.67; As, rs = 0.65; p < 0.01) and the sum of sulfate and nitrate (rs = 0.63; p < 0.01), a proxy for secondary aerosol.

  8. Water soluble aerosols and gases at a UK background site - Part 1: Controls of PM2.5 and PM10 aerosol composition

    NASA Astrophysics Data System (ADS)

    Twigg, M. M.; Di Marco, C. F.; Leeson, S.; van Dijk, N.; Jones, M. R.; Leith, I. D.; Morrison, E.; Coyle, M.; Proost, R.; Peeters, A. N. M.; Lemon, E.; Frelink, T.; Braban, C. F.; Nemitz, E.; Cape, J. N.

    2015-02-01

    There is limited availability of long-term, high temporal resolution, chemically speciated aerosol measurements, which can lead to further insight into the health and environmental impacts of particulate matter. The Monitor for AeRosols and Gases (MARGA, Applikon B.V., NL) allows characterisation of the inorganic components of PM10 and PM2.5 (NH4+, NO3-, SO42-, Cl-, Na+, K+, Ca2+, Mg2+) and inorganic reactive gases (NH3, SO2, HCl, HONO and HNO3) at hourly resolution. The following study presents 6.5 years (June 2006 to December 2012) of quasi-continuous observations of PM2.5 and PM10 using the MARGA at the UK EMEP "Supersite", Auchencorth Moss, SE Scotland. Auchencorth Moss was found to be representative of a remote European site with average total water soluble inorganic mass of PM2.5 of 3.82 μg m-3. Anthropogenically derived secondary inorganic aerosols (sum of NH4+, NO3- and nss-SO42-), were the dominating species (63%) of PM2.5. In terms of equivalent concentrations, NH4+ provided the single largest contribution to PM2.5 fraction in all seasons. Sea salt, was the main component (73%) of the PMcoarse fraction (PM10-PM2.5), though NO3- was also found to make a relatively large contribution to the measured mass (17%) as providing evidence of considerable processing of sea salt in the coarse mode. There was on occasions evidence of aerosol from combustion events being transported to the site in 2012 as high K+ concentrations (deviating from the known ratio in sea salt) coincided with increases in black carbon at the site. Pollution events in PM10 (defined as concentrations > 12 μg m-3) were on average dominated by NH4+ and NO3-, where as smaller loadings at the site tended to be dominated by sea salt. As with other Western European sites, the charge balance of the inorganic components resolved were biased towards cations, suggesting the aerosol was basic or more likely, that organic acids contributed to the charge

  9. Water soluble aerosols and gases at a UK background site - Part 1: Controls of PM2.5 and PM10 aerosol composition

    NASA Astrophysics Data System (ADS)

    Twigg, M. M.; Di Marco, C. F.; Leeson, S.; van Dijk, N.; Jones, M. R.; Leith, I. D.; Morrison, E.; Coyle, M.; Proost, R.; Peeters, A. N. M.; Lemon, E.; Frelink, T.; Braban, C. F.; Nemitz, E.; Cape, J. N.

    2015-07-01

    There is limited availability of long-term, high temporal resolution, chemically speciated aerosol measurements which can provide further insight into the health and environmental impacts of particulate matter. The Monitor for AeRosols and Gases (MARGA, Applikon B.V., NL) allows for the characterisation of the inorganic components of PM10 and PM2.5 (NH4+, NO3-, SO42-, Cl-, Na+, K+, Ca2+, Mg2+) and inorganic reactive gases (NH3, SO2, HCl, HONO and HNO3) at hourly resolution. The following study presents 6.5 years (June 2006 to December 2012) of quasi-continuous observations of PM2.5 and PM10 using the MARGA at the UK EMEP supersite, Auchencorth Moss, SE Scotland. Auchencorth Moss was found to be representative of a remote European site with average total water soluble inorganic mass of PM2.5 of 3.82 μg m-3. Anthropogenically derived secondary inorganic aerosols (sum of NH4+, NO3- and nss-SO42-) were the dominating species (63 %) of PM2.5. In terms of equivalent concentrations, NH4+ provided the single largest contribution to PM2.5 fraction in all seasons. Sea salt was the main component (73 %) of the PMcoarse fraction (PM10-PM2.5), though NO3- was also found to make a relatively large contribution to the measured mass (17 %) providing evidence of considerable processing of sea salt in the coarse mode. There was on occasions evidence of aerosol from combustion events being transported to the site in 2012 as high K+ concentrations (deviating from the known ratio in sea salt) coincided with increases in black carbon at the site. Pollution events in PM10 (defined as concentrations > 12 μg m-3) were on average dominated by NH4+ and NO3-, where smaller loadings at the site tended to be dominated by sea salt. As with other western European sites, the charge balance of the inorganic components resolved were biased towards cations, suggesting the aerosol was basic or more likely that organic acids contributed to the charge balance. This study demonstrates the UK

  10. Trends of particulate matter (PM2.5) and chemical composition at a regional background site in the Western Mediterranean over the last nine years (2002-2010)

    NASA Astrophysics Data System (ADS)

    Cusack, M.; Alastuey, A.; Pérez, N.; Pey, J.; Querol, X.

    2012-09-01

    The time variability and long term trends of PM2.5 (particulate matter of diameter < 2.5 μm) at various regional background (RB) sites across Europe are studied and interpreted in this work. Data on mean annual levels of PM2.5 measured at Montseny (MSY, North East Spain) and various RB sites in Spain and Europe are evaluated and compared, and subsequently analysed for statistically significant trends. The MSY site registered higher average PM2.5 levels than those measured at a selection of other RB sites across Spain, Portugal, Germany and Scandinavia by percentage compared to the mean of all the stations in these countries, but lower than those measured in Switzerland, Italy and Austria. Reductions in PM2.5 were observed across all stations in Spain and Europe to varying degrees (7-49%). MSY underwent a statistically significant reduction since measurements began, indicating a year-on-year gradual decrease (-3.7 μg m-3, calculated from the final year of data compared to the mean). Similar trends were observed in other RB sites across Spain (-1.9 μg m-3). Reductions recorded in PM2.5 across Europe were varied, with many experiencing gradual, year-on-year decreases (-1.8 μg m-3). These reductions have been attributed to various causes: the introduction and implementation of pollution abatement strategies in EU member states, the effect of the current economic crisis on emissions of PM2.5 and the influence of meteorology observed during the winters of 2009 and 2010. In addition, the North Atlantic Oscillation (NAO), a large scale meteorological phenomenon most prevalent during winter, was observed to influence the frequency of Saharan dust intrusions across the Iberian Peninsula. Chemical composition of PM2.5 at MSY is characterised by high levels of organic matter (OM) and sulphate, followed by crustal material, nitrate and ammonia. Sea Spray and elemental carbon (EC) comprised a minor part of the total PM2.5 mass. Statistical trend analysis was performed on the