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Sample records for peeter lniste juhan

  1. Book review: Peeters, H. 2007. Field guide to owls of California and the West

    Treesearch

    Eric D. Forsman

    2010-01-01

    Field Guide to Owls of California and the West. Written primarily for nonprofessionals,this little field guide is a treasure trove of published and unpublished information on the natural history and distribution of owls in the western United States. It covers just about everything you could want to know about owls, from why they take dust baths, to facultative...

  2. Assessing Soldier Individual Differences to Enable Tailored Training

    DTIC Science & Technology

    2010-04-01

    Army Research Institute John Lipinski, U.S. Army Research Institute NOTICES DISTRIBUTION: Primary distribution of this Research...way to measure individual differences with strong criterion and face validity (Lievens, Peeters , & Schollaert, 2007). Attention to detail...Lievens, F., Peeters , G., & Schollaert, E. (2008). Situational judgment tests: a review of recent research. Personnel Review 37 (4), 426-441

  3. Selective Gene Regulation by Androgen Receptor in Prostate Cancer

    DTIC Science & Technology

    2013-10-01

    androgen receptor pathway in prostate cancer. Curr Opin Pharmacol, 2008. 8(4): p. 440-8. 6. Claessens, F., P. Alen , A. Devos, B. Peeters, G...Chem, 1996. 271(32): p. 19013-6. 7. Schoenmakers, E., P. Alen , G. Verrijdt, B. Peeters, G. Verhoeven, W. Rombauts, and F. Claessens, Differential DNA

  4. Navy Enterprise Resource Planning Program: Governance Challenges in Deploying an Enterprise-Wide Information Technology System in the Department of the Navy

    DTIC Science & Technology

    2010-12-01

    Jos Peeters , “Early MRP Systems at Royal Philips Electronics in the 1960s and 1970s,” IEEE Annals of the History of Computing 31, no. 2 (April-June...ERP) - A brief history,” Journal of Operations Management 25, no. 207 (December 2006): 358. 8 Peeters , Early MRP Systems, 58. 9 Massachusetts...history,” Journal of Operations Management 25, no. 207 (December 2006): 358. 11 Jos Peeters , “Early MRP Systems at Royal Philips Electronics in the

  5. Adaptability in Crisis Management: The Role of Organizational Structure

    DTIC Science & Technology

    2013-06-01

    Peeters , van Tuijl, Rutte, & Reymen, 2006). Applying the same logic as the analyses performed on mean scores, ANOVAs were run first on standard... Peeters , M.A.G., van Tuijl, H.F.J.M., Rutte, C.G., & Reymen, I.M.M.J. (2006). Personality and team performance: A meta-analysis. European Journal of...Industrial and Organizational Psychology. Chichester, UK: John Wiley & Sons Ltd. van Bezooijen, B. J. A., Essens, P. J. M. D., & Vogelaar, A. L. W. (2006

  6. Exploitation of Unintentional Information Leakage from Integrated Circuits

    DTIC Science & Technology

    2011-12-01

    identity, the database is updated to reflect the pairing (e.g., device A1 belongs to John Smith). • Classification / feature matching module. For...Anderson. Security Engineering: A Guide to Building Depend- able Distributed Systems. Wiley, January 2001. APSQ06. Cédric Archambeau, Eric Peeters ...Security, IEEE Transactions on, PP(99):1, 2011. To appear. CNPQ03. M. Ciet, M. Neve, E. Peeters , and J.-J. Quisquater. Parallel FPGA implementation of

  7. Analysis of Social Network Measures with Respect to Structural Properties of Networks

    DTIC Science & Technology

    2012-03-01

    stress on a node, is calculated, as shown in Equation (11) (Koschützki, Lehmann, Peeters , & Richter, 2005, pp. 28-29). 18 ( ) ( )S k ij k i j j C p...communication will increase if the corresponding element x is removed from the graph” (Koschützki, Lehmann, Peeters , & Richter, 2005, pp. 36-38). This...Correlation. In Practical Nonparametric Statistics. John Wiley & Sons, Inc. Erdos, P., & Renyi, A. (1960). On the Evolution of Random Graphs. Publ

  8. Analysis of Air Force Secondary Power Logistics Solution Contract

    DTIC Science & Technology

    2010-05-21

    Der~~ Office orlm- peeter General 400 AnnyNa.vy Drivc Arlingtoll, VA � FROM: 448 SCMWIDV SUBJEcr· Audit. Analysis or .~r Force ~..toooruy...LOG I STICS AGENCV HEA DQUARTERS 8725 JOHN J . KINGMAN FlOAD FORT BELVO I R, VIRGI NI A 2:򒯤-622 1 MEMURANDUM f.’OR DA SUBJEct: Analysis

  9. Static and Dynamic Component Obfuscation on Reconfigurable Devices

    DTIC Science & Technology

    2010-03-01

    ed.): protocols, algorithms, and source code in C. John Wiley & Sons, Inc., New York, NY, USA, 1995. ISBN 0-471-11709-9. [18] Sedcole, P., B. Blodget...University of Cambridge, Computer Laboratory, Technical Report UCAM-CL-TR-630, 2005. [21] Standaert, O.-X., E. Peeters , G. Rouvroy, and J.-J. Quisquater

  10. Novel Burkholderia mallei Virulence Factors Linked to Specific Host-Pathogen Protein Interactions

    DTIC Science & Technology

    2013-06-23

    systems. Combinatorial Chem. High Throughput Screening 9, 365–380 73. Brass, A. L., Huang, I. C., Benita, Y., John , S. P., Krishnan, M. N., Feeley, E. M...tion by bacterial effectors: A ubiquitous theme. PLOS Pathogens 8, e1002823 89. Angot, A., Vergunst, A., Genin, S., and Peeters , N. (2007) Exploitation

  11. Army National Guard: Enhancing Public and Employer Support

    DTIC Science & Technology

    2011-01-24

    rundowns/rundown.php?prgId=2&prgDate=4-18- 2009 (accessed 9 October 2010). 20 John Stimac, “Four Governors visit Gaud Troops in Iraq.” National Guard...The National Guard, A Great Value for America, 6. 33 LTC Michael Peeters , businessman, entrepreneur and member of the USAR, interviewed by author, 22

  12. The Cartographic Representation of Linguistic Data. Discussion Papers in Geolinguistics Nos. 19-21. Selected Papers from a Geolinguistic Seminar (Le Pailly, France, September 10-13, 1992).

    ERIC Educational Resources Information Center

    Peeters, Yvo J. D., Ed.; Williams, Colin H., Ed.

    Papers from a conference on cartography in geolinguistics include: "The Political Importance of Visualisation of Language Contact" (Yvo J. D. Peeters); "Some Considerations on People and Boundaries" (Guy Heraud); "Geolinguistic Developments and Cartographic Problems" (Colin H. Williams, John E. Ambrose); "A…

  13. Feasibility of Prostate Cancer Diagnosis by Transrectal Photoacoustic Imaging

    DTIC Science & Technology

    2014-05-01

    and Imaging, John Wiley & Sons (2007). 7. S. Telenkov, A. Mandelis, B. Lashkari, and M. Forcht, “Frequency-domain photothermoacoustics...2009). 31. R. Nachabé, D. J. Evers, B. H. Hendriks, G. W. Lucassen, M. van der Voort, E. J. Rutgers, M. J. Peeters , J. A. Van der Hage, H. S

  14. Book Reviews.

    ERIC Educational Resources Information Center

    International Journal of Early Childhood, 1994

    1994-01-01

    Reviews "La Educacion Preescolar: Desafio y Aventura" (Lavanchy Bobsien); "Working towards Better Childcare" (Peeters and Vandenbroeck, editors); "Children's Savings: A Study in the Development of Economic Behavior" (Sonuga-Barke and Webley); "Curvas de Crecimiento Estaturo-ponderal en Escolares" (Saez Crespo and others); and "Helping Bereaved…

  15. Agent-based Approaches to Dynamic Team Simulation

    DTIC Science & Technology

    2008-09-01

    behavior. The second section reviews agent-based models of teamwork describing work involving both teamwork approaches to design of multiagent systems...there is less direct evidence for teams. Hough (1992), for example, found that ratings on conscientiousness, emotional stability, and agreeableness...Peeters, Rutte, Tuijl, and Reymen (2006) who found agreeableness and emotional stability positively related to satisfaction with the team make

  16. Book Reviews.

    ERIC Educational Resources Information Center

    International Journal of Early Childhood, 1994

    1994-01-01

    Reviews "La Educacion Preescolar: Desafio y Aventura" (Lavanchy Bobsien); "Working towards Better Childcare" (Peeters and Vandenbroeck, editors); "Children's Savings: A Study in the Development of Economic Behavior" (Sonuga-Barke and Webley); "Curvas de Crecimiento Estaturo-ponderal en Escolares" (Saez Crespo and others); and "Helping Bereaved…

  17. "Build Me a Male Role Model!" A Critical Exploration of the Perceived Qualities/Characteristics of Men in the Early Years (0-8) in England

    ERIC Educational Resources Information Center

    Brownhill, Simon

    2014-01-01

    Young boys' "underachievement" and their disaffection with learning continue to dominate education agendas [Francis, B. 2006. "Stop That Sex Drive." "Times Educational Supplement" 30; Peeters, J. 2007. "Including Men in Early Childhood Education: Insights from the European Experience." "NZ Research in…

  18. "Build Me a Male Role Model!" A Critical Exploration of the Perceived Qualities/Characteristics of Men in the Early Years (0-8) in England

    ERIC Educational Resources Information Center

    Brownhill, Simon

    2014-01-01

    Young boys' "underachievement" and their disaffection with learning continue to dominate education agendas [Francis, B. 2006. "Stop That Sex Drive." "Times Educational Supplement" 30; Peeters, J. 2007. "Including Men in Early Childhood Education: Insights from the European Experience." "NZ Research in…

  19. Bobcat (Felis rufus) ecology and management

    USGS Publications Warehouse

    Howell, Judd A.

    1997-01-01

    The bobcat (Felis rufus) is a medium sized predator in the family Felidae found exclusively in North America. Extensive natural history information is available and is summarized in several bibliographies and reviews (Sweeny and Poelker 1977, McCord and Cardoza 1982, Boddicker 1983, Anderson 1987, Rolley 1987). The bobcat is a spotted cat with a short white-tipped tail, small dark ear tufts and is about twice the size of the house cat (Felis domesticus) because of the bobcat’s longer bone structure (McCord and Cardoza 1982, Jameson and Peeters 1988). The bobcat weights between 5- 15 kg with males larger than females. TL 700- 1000, T 95-150, E (from crown) 60-75 (Jameson and Peeters 1988).

  20. Extension of Flutter Boundaries Using In-Flight Receptance Data

    DTIC Science & Technology

    2012-11-01

    G., Random Data: Analysis & Measurement Procedures, Third Edition, John Wiley and Sons, New York, 2000. 18. Peeters , B., Lowet, G., Van der...AFRL-AFOSR-UK-TR-2012-0057 Extension of Flutter Boundaries Using In-Flight Receptance Data Professor John E Mottershead...6. AUTHOR(S) Professor John E Mottershead 5d. PROJECT NUMBER 5d. TASK NUMBER 5e. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S

  1. Finite-Time Performance of Local Search Algorithms: Theory and Application

    DTIC Science & Technology

    2010-06-10

    proven to be .VP-complete using a polynomial 21 transformation from the NF-complete Maximum Edge Biclique Problem ( Peeters 2003). Kao and Jacobson...Goldsman, (1995) Design and Analysis of Experiments for Statistical Selection, Screening, and Multiple Comparisons. John Wiley and Sons, New York. A...34Safe at Home? An Experiment in Domestic Airline Security." Operations Research, 49, 181-195. P. Billingsley (1979). Probability and Measure, John

  2. A Tale of Two Studies: Equal Opportunity Climate and Mission Readiness

    DTIC Science & Technology

    2012-07-24

    Bowler, 2007; LeBlanc, Hox, Schaufeli, Wilmar, Peeters , & Taris, 2007), and the requirement for self-reports of these constructs from a conceptual...1981; Fiske, 1949; Goldberg, 1992; John & A Tale of Two Studies, 32 Srivastava, 1999; McCrae & Costa, 1999; Norman, 1963; Wiggins & Trapnell, 1997...planning, prioritizing, thinking before acting, and following rules and norms) that yields effective task performance ( John & Srivastava, 1999). These

  3. Falconry

    DTIC Science & Technology

    1990-06-01

    Peregrine falcon populations 98. California Hawking Club, Davis Calif. A beginners manual of falconry. Davis, Calif: Pub. by The California Hawking Club...1965]. (SK 321 .H55) Cover has title: A beginners manual of falconry by Steven G. Herman, E.W. Jameson, jr., Hans J. Peeters. "Designed and printed...Introduction written by Rev. Alex. Gillies. cf. Lowndes’ Bibliographer’s manual . E;Ibliotheca Accipitraria #49. Oelgart #6 A 104. Carcano, Francesco

  4. Uncovering the Role of BMP Signaling in Melanocyte Development and Melanoma Tumorigenesis

    DTIC Science & Technology

    2016-09-01

    validated zebrafish-specific array CGH platform. Genes Chromosomes Cancer, 48, 155-70. 10. North, T.E., Goessling, W., Peeters, M., Li, P., Ceol, C.J...number variation (CNV) in the melanoma genome. A major challenge in the field of cancer genomics has been to distinguish, from a chromosomal segment...tagged gdf6b, GST-gdf6b, into two guinea pigs. Antibodies were validated by comparing reactivity of 8 pre- and post-immune sera to bacterially

  5. Cyber Deterrence: Tougher in Theory than in Practice?

    DTIC Science & Technology

    2010-01-01

    and systematic attack to date” on Pentagon networks, according to then–deputy secretary of defense John Hamre, observers jumped to the conclusion of...RAND, 2002), http://www.rand .org/pubs/monograph_reports/MR1619/MR1619.pdf. 7. In Mark Landler and John Markoff, “Digital Fears Emerge after Data Siege...on Estonia targeted its banks. In Peeter Lorents, Rain Ottis, and Raul Rikk, “Cyber Society and Cooperative Cyber Defence,” a paper presented at the

  6. Alcohol consumption and the risk of renal cancers in the European Prospective Investigation into Cancer and Nutrition (EPIC). Wozniak MB, Brennan P, Brenner DR, Overvad K, Olsen A, Tjønneland A, Boutron-Ruault MC, Clavel-Chapelon F, Fagherazzi G, Katzke V, Kühn T, Boeing H, Bergmann MM, Steffen A, Naska A, Trichopoulou A, Trichopoulos D, Saieva C, Grioni S, Panico S, Tumino R, Vineis P, Bueno-de-Mesquita HB, Peeters PH, Hjartåker A, Weiderpass E, Arriola L, Molina-Montes E, Duell EJ, Santiuste C, Alonso de la Torre R, Barricarte Gurrea A, Stocks T, Johansson M, Ljungberg B, Wareham N, Khaw KT, Travis RC, Cross AJ, Murphy N, Riboli E, Scelo G.Int J Cancer. 2015 Oct 15;137(8):1953-66. [Epub 2015 Apr 28]. doi: 10.1002/ijc.29559.

    PubMed

    Jay, Raman; Brennan, P; Brenner; Overvad, K; Olsen, A; Tjønneland, A; Boutron-Ruault, M C; Clavel-Chapelon, F; Fagherazzi; Katzke, V; Kühn, T; Boeing, H; Bergmann, M M; Steffen, A; Naska, A; Trichopoulou, A; Trichopoulos, D; Saieva, C; Grioni, S; Panico, S; Tumino, R; Vineis, P; Bueno-de-Mesquita, H B; Peeters, P H; Hjartåker, A; Weiderpass, E; Arriola, L; Molina-Montes, E; Duell, E J; Santiuste, C; Alonso de la Torre, R; Barricarte Gurrea, A; Stocks, T; Johansson, M; Ljungberg, B; Wareham, N; Khaw, K T; Travis, R C; Cross, A J; Murphy, N; Riboli, E; Scelo, G

    2017-03-01

    Epidemiologic studies have reported that moderate alcohol consumption is inversely associated with the risk of renal cancer. However, there is no information available on the associations in renal cancer subsites. From 1992 to 2010, 477,325 men and women in the European Prospective Investigation into Cancer and Nutrition cohort were followed for incident renal cancers (n = 931). Baseline and lifetime alcohol consumption was assessed by country-specific, validated dietary questionnaires. Information on past alcohol consumption was collected by lifestyle questionnaires. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated from Cox proportional hazard models. In multivariate analysis, total alcohol consumption at baseline was inversely associated with renal cancer; the HR and 95% CI for the increasing categories of total alcohol consumption at recruitment vs. the light drinkers category were 0.78 (0.62-0.99), 0.82 (0.64-1.04), 0.70 (0.55-0.90), and 0.91 (0.63-1.30), respectively, (ptrend = 0.001). A similar relationship was observed for average lifetime alcohol consumption and for all renal cancer subsites combined or for renal parenchyma subsite. The trend was not observed in hypertensive individuals and not significant in smokers. In conclusion, moderate alcohol consumption was associated with a decreased risk of renal cancer. Copyright © 2017. Published by Elsevier Inc.

  7. Commentary on "Plasma carotenoids and vitamin C concentrations and risk of urothelial cell carcinoma in the European Prospective Investigation into Cancer and Nutrition." Ros MM, Bueno de Mesquita HB, Kampman E, Aben KK, Büchner FL, Jansen EH, van Gils CH, Egevad L, Overvad K, Tjønneland A, Roswall N, Boutron Ruault MC, Kvaskoff M, Perquier F, Kaaks R, Chang Claude J, Weikert S, Boeing H, Trichopoulou A, Lagiou P, Dilis V, Palli D, Pala V, Sacerdote C, Tumino R, Panico S, Peeters PH, Gram IT, Skeie G, Huerta JM, Barricarte A, Quirós JR, Sánchez MJ, Buckland G, Larrañaga N, Ehrnström R, Wallström P, Ljungberg B, Hallmans G, Key TJ, Allen NE, Khaw KT, Wareham N, Brennan P, Riboli E, Kiemeney LA, National Institute for Public Health and the Environment, Bilthoven, Netherlands: Am J Clin Nutr 2012;96(4):902-10 [Epub 2012 Sep 5].

    PubMed

    See, William A

    2013-07-01

    Published associations between dietary carotenoids and vitamin C and bladder cancer risk are inconsistent. Biomarkers may provide more accurate measures of nutrient status. We investigated the association between plasma carotenoids and vitamin C and risk of urothelial cell carcinoma (UCC) in a case-control study nested within the European Prospective Investigation into Cancer and Nutrition. A total of 856 patients with newly diagnosed UCC were matched with 856 cohort members by sex, age at baseline, study center, date and time of blood collection, and fasting status. Plasma carotenoids (α- and β-carotene, β-cryptoxanthin, lycopene, lutein, and zeaxanthin) were measured by using reverse-phase HPLC, and plasma vitamin C was measured by using a colorimetric assay. Incidence rate ratios (IRRs) were estimated by using conditional logistic regression with adjustment for smoking status, duration, and intensity. UCC risk decreased with higher concentrations of the sum of plasma carotenoids (IRR for the highest compared with the lowest quartile: 0.64; 95% CI: 0.44, 0.93; P-trend = 0.04). Plasma β-carotene was inversely associated with aggressive UCC (IRR: 0.51; 95% CI: 0.30, 0.88; P-trend = 0.02). Plasma lutein was inversely associated with risk of nonaggressive UCC (IRR: 0.56; 95% CI: 0.32, 0.98; P-trend = 0.05). No association was observed between plasma vitamin C and risk of UCC. Although residual confounding by smoking or other factors cannot be excluded, higher concentrations of plasma carotenoids may reduce risk of UCC, in particular aggressive UCC. Plasma lutein may reduce risk of nonaggressive UCC. Copyright © 2013. Published by Elsevier Inc.

  8. Gray Fox (Urocyon cinereoargenteus) ecology and management

    USGS Publications Warehouse

    Howell, Judd A.

    1997-01-01

    The gray fox (Urocyon cinereoargenteus) is a petite member of the family Canidae in the order Carnivora with a long muzzle and pointed ears (Samuel and Nelson 1982). The coat of the gray fox is silver gray across the back with significant amounts of rufus along the sides. This characteristic is often confused by people who see the flash of red and assume that the fox is a red fox (Vulpes vulpes). The gray fox has a black tipped tail with a dorsal black stripe that differentiates this species from the kit fox (Vulpes macrotis). The red fox has a white tipped tail. The gray fox weighs between 3-5 kg, occasionally to 7 kg. TL 800-1125, T 275-443, HF 100-150. (Jameson and Peeters 1988).

  9. A triclinic polymorph of (-)-(S)-N-benzyl-2-[(R)-6-fluoro-chroman-2-yl]-2-hy-droxy-ethanaminium bromide.

    PubMed

    Rousselin, Yoann; Laureano, Hugo; Clavel, Alexandre

    2013-12-01

    The title salt, C18H21FNO2 (+)·Br(-), determined at 115 K, crystallizes in the triclinic space group P1. The previously reported polymorph occurs in the monoclinic space group P21 and has two independent mol-ecules in the asymmetric unit [Peeters et al. (1993 ▶). Acta Cryst. C49, 2157-2160]. In the title molecule, the pyran rings adopt half-chair conformations. The absolute configuration is S for the hy-droxy-bearing C atom and R for the asymmetric C atom in the di-hydro-pyran unit. In the crystal, the components are linked by N-H⋯Br and O-H⋯Br hydrogen bonds, forming chains along the c-axis direction. The crystal studied was refined as an inversion twin.

  10. Normal Modes of Magnetized Finite Two-Dimensional Yukawa Crystals

    NASA Astrophysics Data System (ADS)

    Marleau, Gabriel-Dominique; Kaehlert, Hanno; Bonitz, Michael

    2009-11-01

    The normal modes of a finite two-dimensional dusty plasma in an isotropic parabolic confinement, including the simultaneous effects of friction and an external magnetic field, are studied. The ground states are found from molecular dynamics simulations with simulated annealing, and the influence of screening, friction, and magnetic field on the mode frequencies is investigated in detail. The two-particle problem is solved analytically and the limiting cases of weak and strong magnetic fields are discussed.[4pt] [1] C. Henning, H. K"ahlert, P. Ludwig, A. Melzer, and M.Bonitz. J. Phys. A 42, 214023 (2009)[2] B. Farokhi, M. Shahmansouri, and P. K. Shukla. Phys.Plasmas 16, 063703 (2009)[3] L. Cândido, J.-P. Rino, N. Studart, and F. M. Peeters. J. Phys.: Condens. Matter 10, 11627--11644 (1998)

  11. On the nature of fermion-monopole supersymmetry

    NASA Astrophysics Data System (ADS)

    Plyushchay, M. S.

    2000-07-01

    It is shown that the generator of the nonstandard fermion-monopole supersymmetry uncovered by De Jonghe, Macfarlane, Peeters and van Holten, and the generator of its standard /N=1/2 supersymmetry have to be supplemented by their product operator to be treated as independent supercharge. As a result, the fermion-monopole system possesses the nonlinear /N=3/2 supersymmetry having the nature of the 3D spin-1/2 free particle's supersymmetry generated by the supercharges represented in a scalar form. Analyzing the supercharges' structure, we trace how under reduction of the fermion-monopole system to the spherical geometry the nonlinear /N=3/2 superalgebra comprising the Hamiltonian and the total angular momentum as even generators is transformed into the standard linear /N=1 superalgebra with the Hamiltonian to be the unique even generator.

  12. A triclinic polymorph of (−)-(S)-N-benzyl-2-[(R)-6-fluoro­chroman-2-yl]-2-hy­droxy­ethanaminium bromide

    PubMed Central

    Rousselin, Yoann; Laureano, Hugo; Clavel, Alexandre

    2013-01-01

    The title salt, C18H21FNO2 +·Br−, determined at 115 K, crystallizes in the triclinic space group P1. The previously reported polymorph occurs in the monoclinic space group P21 and has two independent mol­ecules in the asymmetric unit [Peeters et al. (1993 ▶). Acta Cryst. C49, 2157–2160]. In the title molecule, the pyran rings adopt half-chair conformations. The absolute configuration is S for the hy­droxy-bearing C atom and R for the asymmetric C atom in the di­hydro­pyran unit. In the crystal, the components are linked by N—H⋯Br and O—H⋯Br hydrogen bonds, forming chains along the c-axis direction. The crystal studied was refined as an inversion twin. PMID:24860291

  13. Observation and modelling of OH and HO2 concentrations in the Pearl River Delta 2006: a missing OH source in a VOC rich atmosphere

    NASA Astrophysics Data System (ADS)

    Lu, K. D.; Rohrer, F.; Holland, F.; Fuchs, H.; Bohn, B.; Brauers, T.; Chang, C. C.; Häseler, R.; Hu, M.; Kita, K.; Kondo, Y.; Li, X.; Lou, S. R.; Nehr, S.; Shao, M.; Zeng, L. M.; Wahner, A.; Zhang, Y. H.; Hofzumahaus, A.

    2011-04-01

    Ambient OH and HO2 concentrations were measured by laser induced fluorescence (LIF) during the PRIDE-PRD2006 (Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta, 2006) campaign at a rural site downwind of the megacity of Guangzhou in Southern China. The observed OH concentrations reached daily peak values of (15-26) × 106 cm-3 which are among the highest values so far reported for urban and suburban areas. The observed OH shows a consistent high correlation with j(O1D) over a broad range of NOx conditions. The correlation cannot be reproduced by model simulations, indicating that OH stabilizing processes are missing in current models. The observed OH exhibited a weak dependence on NOx in contrast to model predictions. While modelled and measured OH agree well at NO mixing ratios above 1 ppb, a continuously increasing underprediction of the observed OH is found towards lower NO concentrations, reaching a factor of 8 at 0.02 ppb NO. A dependence of the modelled-to-measured OH ratio on isoprene cannot be concluded from the PRD data. However, the magnitude of the ratio fits into the isoprene dependent trend that was reported from other campaigns in forested regions. Hofzumahaus et al. (2009) proposed an unknown OH recycling process without NO, in order to explain the high OH levels at PRD in the presence of high VOC reactivity and low NO. Taking a recently discovered interference in the LIF measurement of HO2 into account, the need for an additional HO2 → OH recycling process persists, but the required source strength may be up to 20% larger than previously determined. Recently postulated isoprene mechanisms by Lelieveld et al. (2008) and Peeters and Müller (2010) lead to significant enhancements of OH expected for PRD, but an underprediction of the observed OH by a factor of two remains at low NO (0.1-0.2 ppb). If the photolysis of hydroperoxy aldehydes from isoprene is as efficient as proposed by Peeters and Müller (2010), the

  14. Observation and modelling of OH and HO2 concentrations in the Pearl River Delta 2006: a missing OH source in a VOC rich atmosphere

    NASA Astrophysics Data System (ADS)

    Lu, K. D.; Rohrer, F.; Holland, F.; Fuchs, H.; Bohn, B.; Brauers, T.; Chang, C. C.; Häseler, R.; Hu, M.; Kita, K.; Kondo, Y.; Li, X.; Lou, S. R.; Nehr, S.; Shao, M.; Zeng, L. M.; Wahner, A.; Zhang, Y. H.; Hofzumahaus, A.

    2012-02-01

    Ambient OH and HO2 concentrations were measured by laser induced fluorescence (LIF) during the PRIDE-PRD2006 (Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta, 2006) campaign at a rural site downwind of the megacity of Guangzhou in Southern China. The observed OH concentrations reached daily peak values of (15-26) × 106 cm-3 which are among the highest values so far reported for urban and suburban areas. The observed OH shows a consistent high correlation with j(O1D) over a broad range of NOx conditions. The correlation cannot be reproduced by model simulations, indicating that OH stabilizing processes are missing in current models. The observed OH exhibited a weak dependence on NOx in contrast to model predictions. While modelled and measured OH agree well at NO mixing ratios above 1 ppb, a continuously increasing underprediction of the observed OH is found towards lower NO concentrations, reaching a factor of 8 at 0.02 ppb NO. A dependence of the modelled-to-measured OH ratio on isoprene cannot be concluded from the PRD data. However, the magnitude of the ratio fits into the isoprene dependent trend that was reported from other campaigns in forested regions. Hofzumahaus et al. (2009) proposed an unknown OH recycling process without NO, in order to explain the high OH levels at PRD in the presence of high VOC reactivity and low NO. Taking a recently discovered interference in the LIF measurement of HO2 into account, the need for an additional HO2 → OH recycling process persists, but the required source strength may be up to 20% larger than previously determined. Recently postulated isoprene mechanisms by Lelieveld et al. (2008) and Peeters and Müller (2010) lead to significant enhancements of OH expected for PRD, but an underprediction of the observed OH by a factor of two remains at low NO (0.1-0.2 ppb). If the photolysis of hydroperoxy aldehydes from isoprene is as efficient as proposed by Peeters and Müller (2010), the

  15. Cavity Ringdown Spectroscopy and Kinetics of HO_2+HCHO: Detection of the ν_1 and {A}- {X} Bands of HOCH_2OOCAVITY Ringdown Spectroscopy and Kinetics of HO_2+HCHO: Detection of the ν_1 and {A}- {X} Bands of HOCH_2OO

    NASA Astrophysics Data System (ADS)

    Sprague, Matthew K.; Okumura, Mitchio; Sander, Stanley P.

    2011-06-01

    The reactions of HO_2 with carbonyl compounds are believed to be a sink for carbonyl compounds in the upper troposphere and lower stratosphere. These reactions proceed through a hydrogen bound intermediate before isomerizing. The reaction of HO_2 + formaldehyde (HCHO) serves as a prototype for this class of reactions, forming the isomerization product hydroxymethylperoxy (HOCH_2OO, HMP). Previous studies measured the spectrum and kinetics of HMP using either FTIR detection of the end products or direct detection of HMP by the unstructured tilde{B}-tilde{X} transition. Despite these studies, considerable uncertainty exists in the rate constant of HMP formation (±80%, 2σ). In this talk, we report the first detection of the ν_1 (OH stretch) and tilde{A}-tilde{X} electronic spectra of the HMP radical. The OH stretch spectrum is broad and featureless, while the tilde{A}(0)-tilde{X}(0) origin and combination band with the OOCO torsion tilde{A}(NOOCO=1)-tilde{X}(0) are rotationally resolved. Quantum chemistry calculations have been performed on both the tilde{A} and tilde{X} states as a function of the OOCO and HOCO dihedral angles to estimate the tilde{A}-tilde{X} transition frequency and to assess the coupling between the two torsional modes. We also present kinetics data showing the rates of production and destruction of HMP. I. Hermans, J. F. Muller, T. L. Nguyen, P. A. Jacobs, and J. Peeters. J. Phys. Chem. A 2005, 109, 4303. F. Su, J. G. Calvert, and J. H. Shaw J. Phys. Chem. 1979, 83, 3185. B. Veyret, R. Lesclaux, M. T. Rayez, J. C. Rayez, R. A. Cox, and G. K. Moortgat J. Phys. Chem. 1989, 93, 2368. J. P. Burrows, G. K. Moortgat, G. S. Tyndall, R. A. Cox, M. E. Jenkin, G. D. Hayman, and B. Veyret J. Phys. Chem. 1989, 93, 2375 S. P. Sander, B. J. Finlayson-Pitts, D. M. Golden, R. E. Huie, C. E. Kolb, M. J. Kurylo, M. J. Molina, et al. Chemical Kinetics and Photochemical Data for Use in Atmospheric Studies, Evaluation Number 16, Jet Propulsion Laboratory, 2009 I

  16. Infrared spectra of interstellar deuteronated PAHs

    NASA Astrophysics Data System (ADS)

    Buragohain, Mridusmita; Pathak, Amit; Sarre, Peter

    2015-08-01

    Polycyclic Aromatic Hydrocarbon (PAH) molecules have emerged as a potential constituent of the ISM that emit strong features at 3.3, 6.2, 7.7, 8.6, 11.2 and 12.7 μm with weaker and blended features in the 3-20μm region. These features are proposed to arise from the vibrational relaxation of PAH molecules on absorption of background UV photons (Tielens 2008). These IR features have been observed towards almost all types of astronomical objects; say H II regions, photodissociation regions, reflection nebulae, planetary nebulae, young star forming regions, external galaxies, etc. A recent observation has proposed that interstellar PAHs are major reservoir for interstellar deuterium (D) (Peeters et al. 2004). According to the `deuterium depletion model' as suggested by Draine (2006), some of the Ds formed in the big bang are depleted in PAHs, which can account for the present value of D/H in the ISM. Hence, study of deuterated PAHs (PADs) is essential in order to measure D/H in the ISM.In this work, we consider another probable category of the large PAH family, i.e. Deuteronated PAHs (DPAH+). Onaka et al. have proposed a D/H ratio which is an order of magnitude smaller than the proposed value of D/H by Draine suggesting that if Ds are depleted in PAHs, they might be accommodated in large PAHs (Onaka et al. 2014). This work reports a `Density Functional Theory' calculation of large deuteronated PAHs (coronene, ovalene, circumcoronene and circumcircumcoronene) to determine the expected region of emission features and to find a D/H ratio that is comparable to the observational results. We present a detailed analysis of the IR spectra of these molecules and discuss the possible astrophysical implications.ReferencesDraine B. T. 2006, in ASP Conf. Ser. 348, Proc. Astrophysics in the Far Ultraviolet: Five Years of Discovery with FUSE, ed. G. Sonneborn, H. Moos, B-G Andersson (San Francisco, CA:ASP) 58Onaka T., Mori T. I., Sakon I., Ohsawa R., Kaneda H., Okada Y., Tanaka M

  17. Investigation of the β-pinene photooxidation by OH in the atmosphere simulation chamber SAPHIR

    NASA Astrophysics Data System (ADS)

    Kaminski, Martin; Fuchs, Hendrik; Acir, Ismail-Hakki; Bohn, Birger; Brauers, Theo; Dorn, Hans-Peter; Häseler, Rolf; Hofzumahaus, Andreas; Li, Xin; Lutz, Anna; Nehr, Sascha; Rohrer, Franz; Tillmann, Ralf; Vereecken, Luc; Wegener, Robert; Wahner, Andreas

    2017-06-01

    Besides isoprene, monoterpenes are the non-methane volatile organic compounds (VOCs) with the highest global emission rates. Due to their high reactivity towards OH, monoterpenes can dominate the radical chemistry of the atmosphere in forested areas. In the present study the photochemical degradation mechanism of β-pinene was investigated in the Jülich atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber). One focus of this study is on the OH budget in the degradation process. Therefore, the SAPHIR chamber was equipped with instrumentation to measure radicals (OH, HO2, RO2), the total OH reactivity, important OH precursors (O3, HONO, HCHO), the parent VOC β-pinene, its main oxidation products, acetone and nopinone and photolysis frequencies. All experiments were carried out under low-NO conditions ( ≤ 300 ppt) and at atmospheric β-pinene concentrations ( ≤ 5 ppb) with and without addition of ozone. For the investigation of the OH budget, the OH production and destruction rates were calculated from measured quantities. Within the limits of accuracy of the instruments, the OH budget was balanced in all β-pinene oxidation experiments. However, even though the OH budget was closed, simulation results from the Master Chemical Mechanism (MCM) 3.2 showed that the OH production and destruction rates were underestimated by the model. The measured OH and HO2 concentrations were underestimated by up to a factor of 2, whereas the total OH reactivity was slightly overestimated because the model predicted a nopinone mixing ratio which was 3 times higher than measured. A new, theory-derived, first-generation product distribution by Vereecken and Peeters (2012) was able to reproduce the measured nopinone time series and the total OH reactivity. Nevertheless, the measured OH and HO2 concentrations remained underestimated by the numerical simulations. These observations together with the fact that the measured OH budget

  18. A new gas-phase condensed mechanism of isoprene-NO x photooxidation

    NASA Astrophysics Data System (ADS)

    Zhang, Haofei; Rattanavaraha, Weruka; Zhou, Yang; Bapat, Jyoti; Rosen, Elias P.; Sexton, Kenneth G.; Kamens, Richard M.

    2011-08-01

    A new condensed gas-phase isoprene mechanism is developed and evaluated, using O 3, nitrogen oxides (NO x), and volatile organic compounds (VOC) data from over twenty isoprene experiments. Experiments were performed in two UNC dual outdoor smog chambers using natural sunlight, with different NO x levels, and with or without the presence of an urban hydrocarbon environment. The mechanism uses the Carbon Bond mechanism (CB05) to represent inorganic chemistry and hydrocarbons other than isoprene. It was designed so that the chemistry related to secondary organic aerosol (SOA) formation can be incorporated, and thus it can be further expanded into a gas-aerosol-phase mechanism. A box model framework of this new isoprene mechanism is able to reasonably simulate most experimental data at HC/NO x ratios that range from 0.3 to 18. An intercomparison was performed between the isoprene kinetics developed in this study and other isoprene chemistry that is included in other kinetic mechanisms, including MCM v3.1, SAPRC99, SAPRC07, MIM2, CB4 and CB05. The results indicate that most current mechanisms tend to under-predict ozone levels to different extents, while the new mechanism simulates the UNC smog chamber O 3 data better than the others in most cases, especially at higher HC/NO x ratios. Further, the new mechanism performs reasonably well in modeling outdoor smog chamber experiments with isoprene in an urban hydrocarbon mixture. In addition, a HO x (OH + HO 2) recycling scheme based upon Peeters et al. (2009) and Archibald et al. (2010b) was implemented in MCM v3.1 and the new UNC mechanism, since it has been recently been suggested to be very important under low-NO x conditions. Although our experimental data base is very limited for the low-NO x condition, the Peeters et al. (2009) isoprene chemistry tended to significantly over-predict observed chamber O 3. This suggests that more low-NO x experiments and further confirmation of current theoretical studies are needed.

  19. Coronene and Pyrene (5,7)-member Ring Defects

    NASA Astrophysics Data System (ADS)

    Oettl, Silvia; Kimeswenger, Stefan; Huber, Stefan E.

    2015-08-01

    Polycyclic aromatic hydrocarbons (PAHs) are known to be one of the carriers of the omnipresent aromatic infrared bands that are frequently observed in different astrophysical environments (e.g., Peeters et al. 2004, Draine & Li 2007, Tielens 2008, Bauschlicher et al. 2009, Peeters 2011). Although PAH features are identified in a wide variety of environments, the characteristics of the individual molecules is not clear so far. Several emission features are observed, but cannot be explained. Therefore a sophisticated understanding of all possible types and subtypes is required. We present an investigation of the IR spectra of PAHs containing (5, 7)-member ring defects. Using density functional theory, the influence of those defects on the IR spectra of coronene (C24H12)and pyrene (C16H10) and their cations and anions were examined in detail. Additionally, the potential energy surface of the neutral species is explored and an alternative formation pathway is taken into account.The addition of the pentagons and heptagons instead of some of the hexagons usually constituting PAHs result in a change of the IR spectra: coronene and pyrene lose both their typical spectroscopic signature. We find different additional features and shifts in the positions of the band. Also the intensities differ. Both molecules are among the smallest PAHs that can exhibit such a ring defect. The minimum activation barriers for the transformation from ground to defected state can be found via investigating the minimum energy pathway. This leads to a result of 8.21 eV for pyrene and 8.41 eV for coronene. Pyrene retains some of its symmetry due to the symmetry exhibited by the Stone-Wales defect itself. However, coronene loses much more of its symmetry. The formation of these (5, 7)-member ring defects in PAHs may be well supported in asymptotic giant branch stars or planetary nebulae. These environments strongly enable the transition from the ground to the defected state. Therefore, the

  20. Past changes of landscape due to increased dynamics of erosion processes in the Bezděz-Doksy region (Czech Republic)

    NASA Astrophysics Data System (ADS)

    Vysloužilová, Barbora; Dreslerová, Dagmar; Kozáková, Radka; Poništiak, Štefan; Chuman, Tomáš; Šefrna, Luděk

    2016-04-01

    This study broadens the archaeological research of the the Bezděz - Doksy region in Northern Bohemia, Czech Republic (Dreslerová et al., 2013). Extensive field works between 2008 and 2012 showed that the region has been settled since the La Tène period. Survey of the alluvial plain of the Robečský stream revealed a record of two intensive erosion episodes in the catchment. We suppose that the first episode may be connected to land use changes and the beginnings of agriculture at the site in the La Tène period. The second episode may be connected to the foundation of the medieval village of Okna, which came into existence in the vicinity of the La Tène settlement. The accelerated erosion of former albeluvisols (on loess) led to significant changes of landscape in the region. The aim of this contribution is to bring a reconstruction of soils, vegetation and relief at the site of Okna before the human occupancy and to detect landscape changes over the time. It focuses on the hypothesis that the accelerated soil erosion has been occurring at the site since the first anthropogenic influence like it is demonstrated by other studies in Europe (e.g. Leopold and Völkel, 2007; Boardman, 2013). An abrupt change of land use from forest to arable land is proved by palynological records. Simultaneously there are buried soil horizons and alluvial sediments which can be studied as geoarchives. The difficulties in reconstruction of relief and quantification of the historical erosion effects are faced by applying GIS and model approaches (Peeters et al., 2003). References Boardman, J., 2013. Soil Erosion in Britain: Updating the Record. Agriculture 3, 418-442. doi:10.3390/agriculture3030418 Dreslerová, D., Waldhauser, J., Abraham, V., Kočár, P., Křivánek, R., Meduna, P., Sádlo, J., 2013. The Bezděz - Doksy region (Northern Bohemia) in prehistory and the La Tène settlement at Okna (in Czech). Archeologické rozhledy LXV, 535-573. Leopold, M., Völkel, J., 2007

  1. Gyrokinetic theory and simulation of angular momentum transport

    SciTech Connect

    Waltz, R. E.; Staebler, G. M.; Candy, J.; Hinton, F. L.

    2007-12-15

    A gyrokinetic theory of turbulent toroidal angular momentum transport as well as modifications to neoclassical poloidal rotation from turbulence is formulated starting from the fundamental six-dimensional kinetic equation. The gyro-Bohm scaled transport is evaluated from toroidal delta-f gyrokinetic simulations using the GYRO code [Candy and Waltz, J. Comput. Phys. 186, 545 (2003)]. The simulations recover two pinch mechanisms in the radial transport of toroidal angular momentum: The slab geometry ExB shear pinch [Dominguez and Staebler, Phys. Fluids B 5, 387 (1993)] and the toroidal geometry 'Coriolis' pinch [Peeters, Angioni, and Strintzi, Phys. Rev. Lett. 98, 265003 (2007)]. The pinches allow the steady state null stress (or angular momentum transport flow) condition required to understand intrinsic (or spontaneous) toroidal rotation in heated tokamak without an internal source of torque [Staebler, Kinsey, and Waltz, Bull. Am. Phys. Soc. 46, 221 (2001)]. A predicted turbulent shift in the neoclassical poloidal rotation [Staebler, Phys. Plasmas 11, 1064 (2004)] appears to be small at the finite relative gyroradius (rho-star) of current experiments.

  2. Frequency bands of strongly nonlinear homogeneous granular systems.

    PubMed

    Lydon, Joseph; Jayaprakash, K R; Ngo, Duc; Starosvetsky, Yuli; Vakakis, Alexander F; Daraio, Chiara

    2013-07-01

    Recent numerical studies on an infinite number of identical spherical beads in Hertzian contact showed the presence of frequency bands [Jayaprakash, Starosvetsky, Vakakis, Peeters, and Kerschen, Nonlinear Dyn. 63, 359 (2011)]. These bands, denoted here as propagation and attenuation bands (PBs and ABs), are typically present in linear or weakly nonlinear periodic media; however, their counterparts are not intuitive in essentially nonlinear periodic media where there is a complete lack of classical linear acoustics, i.e., in "sonic vacua." Here, we study the effects of PBs and ABs on the forced dynamics of ordered, uncompressed granular systems. Through numerical and experimental techniques, we find that the dynamics of these systems depends critically on the frequency and amplitude of the applied harmonic excitation. For fixed forcing amplitude, at lower frequencies, the oscillations are large in amplitude and governed by strongly nonlinear and nonsmooth dynamics, indicating PB behavior. At higher frequencies the dynamics is weakly nonlinear and smooth, in the form of compressed low-amplitude oscillations, indicating AB behavior. At the boundary between the PB and the AB large-amplitude oscillations due to resonance occur, giving rise to collisions between beads and chaotic dynamics; this renders the forced dynamics sensitive to initial and forcing conditions, and hence unpredictable. Finally, we study asymptotically the near field standing wave dynamics occurring for high frequencies, well inside the AB.

  3. Diphthongs in the repopulated vowel space

    NASA Astrophysics Data System (ADS)

    Bogacka, Anna

    2005-04-01

    The study examined 8 British English diphthongs produced by Polish learners of English, testing the diphthongs' quality, duration, nasalization, and occurrence of glottal stops before the diphthongs. There were twelve conditions in which the diphthongs were tested: word-initial, word-final, before a voiced obstruent, before a voiceless obstruent, before a nasal consonant, and before a nasal consonant followed by a fricative, and each of these conditions was tested in a stressed and unstressed position. The diphthongs were tested in real words, embedded in sentences, controlled for the stress position, rhythmic units, and length. The sentences were read by 8 female and 8 male Polish learners of English and control subjects. The aim of the phonetic analysis done with Praat, and employing the methodologies used by Flege (1995) for SLA and Peeters (1991) and Jacewicz, Fujimara, and Fox (2003) for diphthongs, is to examine the shape of the restructured vowel space (Liljencrants and Lindblom 1972; Stevens 1989). The approach taken here is termed Vowel Space Repopulation to emphasize that the vowel space of Polish speakers of English is re-structured by new categories in complex ways which are not adequately captured by traditional notions such as ``transfer,'' ``interference,'' or ``interlanguage.''

  4. Purification of rat liver particulate neutral ribonuclease and comparison of properties with pancreas and serum ribonucleases.

    PubMed Central

    Bartholeyns, J; Baudhuin, P

    1977-01-01

    Rat liver particulate neutral ribonuclease (EC 3.1.4.22) was extensively purified (up to 40000-fold). It is shown to be an endonuclease, specific for pyrimidine bases, hydrolysing 5'-phosphate ester bonds. The enzyme specificity, Km, pH optimum, stability in acid medium and thermal stability at high temperature are the same as those of rat pancreatic and serum ribonucleases. Like pancreatic and serum neutral ribonucleases, the hepatic enzyme is sensitive to the liver natural inhibitor. This inhibitor was purified 8000-fold; its association with ribonuclease follows zero-order kinetics. These identical properties for ribonuclease of rat liver, pancreas and serum support the hypothesis [Bartholeyns, Peeters-Joris & Baudhuin (1975) Eur. J. Biochem. 60, 385-393] of an extrahepatic origin for the liver enzyme, the plasma ribonuclease of pancreatic origin being taken up by endocytosis in the liver. Neutral ribonuclease activity was detected in all rat organs investigated; its distribution among tissues is different from the distribution of the natural ribonuclear inhibitor. PMID:19011

  5. Hydroxyl Radical Regeneration in Isoprene Oxidation: the Upgraded Mechanism LIM1

    NASA Astrophysics Data System (ADS)

    Peeters, J.; Nguyen, S.; Nguyen, T.; Stavrakou, T.; Muller, J. J.

    2012-12-01

    Measured hydroxyl radical concentrations in isoprene-rich areas are much higher than predicted by existing chemical models, to the extent that the global oxidizing capacity of our atmosphere should be significantly revised upwards. The OH regeneration that clearly occurs in isoprene oxidation at low/moderate NO is attributed in the Leuven Isoprene Mechanism to novel, theoretically characterized chemical pathways (LIM0: Peeters et al. 2009; Peeters and Muller 2010). The key new features of LIM0 are (i) thermal equilibration of the labile beta-OH- and delta-OH-isoprenylperoxy isomers; (ii) 1,6-H shift isomerisation of the Z-delta-OH-peroxy isomers to yield hydroperoxy-methyl-butenals (HPALDs); (iii) fast photolysis of the HPALDs resulting overall in several OH radicals per HPALD. The OH-regeneration through photolabile HPALDs has recently found experimental support, but the peroxy isomerisation rate, HPALD yield and the extent of OH recycling are still uncertain (Crounse et al. 2011; Wolfe et al. 2012). In this work, the upgraded LIM1 mechanism is presented. Based on better levels of theory, the crucial equilibrium ratio of the isomerising Z-delta-OH-peroxys over the majority beta-OH-isoprenylperoxys had to be reduced by a factor of about 5 compared to LIM0, while the isomerisation rate of the Z-delta-OH-peroxys adopted from Taraborrelli et al. (2012) is about 3 times lower than in LIM0. The chemistry following the 1,6-H shift of the Z-delta-OH-peroxys is much expanded and extended. Firstly, LIM1 introduces other pathways beside HPALD formation following the Z-delta-OH-peroxy isomerisation, resulting likewise in OH recycling. This, together with the revised Z-delta-OH- equilibrium and isomerisation data above, affords a close model-reproduction of the HPALD and other product yields observed by Crounse et al. (2011). Secondly, LIM1 proposes new fast reactions of HO2 with the alpha-oxoketene products from the peroxy isomerisation routes; these reactions are shown to

  6. Hydrophysical and hydrochemical features of Lake Issyk-Kul (Kyrgyzstan) as revealed by field survey of June, 2015

    NASA Astrophysics Data System (ADS)

    Zavialov, Peter; Makkaveev, Petr; Rimskiy-Korsakov, Nikolay; Alymkulov, Salmor; Izhitskiy, Alexander

    2016-04-01

    cycle. However, the vertical profiles of dissolved oxygen indicated that the most intense photosynthetic activity took place in the intermediate layers, while in the surface layer it was suppressed, hypothetically, by excessive insolation. The ionic salt content of the Issyk-Kul waters was essentially uniform throughout the water column, which points towards efficient mixing in the cold period. In summer season, temperature stratification was sufficiently strong to provide for significant reduction of dissolved oxygen and increase of nutrients in the bottom layer. Samples collected and analyzed for dissolved methane generally yielded low concentrations below 0.5 μl/l at the surface and 0.2 μl/l in the bottom layer, however, values as high as to 3.9 μl/l were documented in some samples corresponding to near-shore stations at depths of about 70 m. We also used a towed side-looking sonar to obtain detailed maps of bathymetric features, including the channels formed by ancient beds of the Tyup and the Dzhergalan Rivers. These channels are believed to represent important pathways for ventilated water and terrigenic substances penetrating into the deep central part of the lake following seasonal differential cooling on the eastern shelf (Peeters et al., 2003). Quantitative assessment of this plausible mechanism is subject to future work. References Oberhansli, H., and P. Molnar (2012) Climate evolution in Central Asia during the past few million years: A case study from Issyk-Kul. Scientific Drilling, 13, doi: 10.2204/iodp/sd.13.09.2011 Peeters F, Finger D, Hofer M, Brennwald M, Livingstone DM, Kipfer R (2003) Deep-water renewal in Lake Issyk-Kul driven by differential cooling. Limnol. and Oceanogr. 48: 1419- 1431.

  7. Investigating the impact of millennial scale Agulhas Current System variability on global ocean circulation and climate

    NASA Astrophysics Data System (ADS)

    Simon, M.; Hall, I. R.; Barker, S.; Ziegler, M.

    2012-04-01

    silt mean grain sizes together with δ18O and δ13C data measured on the benthic foraminiferal species Cibicidoides wuellerstorfi are used to construct high-resolution records of near-bottom flow vigour and deep water ventilation at the core site (3300 m water depth), which is today influenced by the Agulhas Undercurrent. The results highlight source water change from North Atlantic Deep Waters (NADW) to Antarctic originated Bottom Waters at the core site that can be linked with colder surface temperatures and higher bottom water flow speed during Marine Isotope Stage 2 (MIS 2), at around 26,000 years ago. A comparison of our "upstream" SST variability with previously published records from the immediate Agulhas Corridor (Martínez Méndez et al, 2010; Cape Basin Record (CBR), Schneider et al., 1999, Peeters et al. 2004), shows that our SST record has a more pronounced temperature variability compared to reconstructions based on the biomarker UK'37 (Peeters et al. 2004), while the early warming trend observed prior to TI (based on Mg/Ca of Globigerinoides bulloides; Martínez Méndez et al. 2010) is not seen in our upstream record. All data have been generated within the EU Marie Curie GATEWAYS project.

  8. The sensitivity of laser induced fluorescence instruments at low pressure to RO2 radicals and the use of this detection method to determine the yield of HO2 during OH-initiated isoprene oxidation

    NASA Astrophysics Data System (ADS)

    Heard, D. E.; Whalley, L. K.; Blitz, M. A.; Seakins, P. W.

    2011-12-01

    a dry air flow at variable positions along the flow-tube; Isoprene was added downstream of the lamp. Theoretical studies (Peeters et al., 2009) suggest an HO2 yield of 0.7 on a time-scale of a few seconds. Results from the recent laboratory studies will be discussed. Fuchs, H., Bohn, B., Hofzumahaus, A., Holland, F., Lu, K., Nehr, S., Rohrer, F., and Wahner, A.: Detection of HO2 by laser-induced fluorescence: Calibration and interferences from RO2 radicals, Atmos Meas Tech Discuss, 4, 1255-1302, 2011. Heard, D. E., and Pilling, M. J.: Measurement of OH and HO2 in the troposphere, Chem Rev, 103, 5163-5198, 2003. Peeters, J., Nguyen, T. L., and Vereecken, L.: HOx radical regeneration in the oxidation of isoprene, Phys Chem Chem Phys, 11, 5935-5939, 2009.

  9. PREFACE: 21st Latin American Symposium on Solid State Physics (SLAFES XXI)

    NASA Astrophysics Data System (ADS)

    Aguiar, J. Albino

    2014-04-01

    Colombia e-mail: dalandinezt@unal.edu.co Professor Laura T Corredor Bohórquez Departamento de Física Universidade Federal de Pernambuco 50670-901 Recife PE Brazil e-mail: ltcorredorb@df.ufpe.br Professor Arkady Shanenko Departamento de Física Universidade Federal de Pernambuco 50670-901 Recife PE Brazil e-mail: arkadyshanenko@df.ufpe.br Professor Renato F Jardim Instituto de Física Universidade de S\\~ao Paulo CP 66318 S\\~ao Paulo SP Brazil e-mail: rjardim@if.usp.br Professor Francois Peeters Department Fysica Universiteit Antwerpen Groneneborgerlann 171 B-2020, Antwerpen Belgium e-mail: francois.peeters@uantwerpen.be Organizing committee ChairmanCarlos Arturo Parra Vargas Proceedings EditorJosé Albino Aguiar Program ChairJairo Roa-Rojas SecretaryAura Janeth Barón González TreasurerArmando Sarmiento Santos Speaker ChairRafael González Hernández Fernando Naranjo Mayorga David A Landínez Téllez Jesús Oswaldo Morán José Sierra Ortega

  10. Impacts of mechanistic changes on HOx formation and recycling in the oxidation of isoprene

    NASA Astrophysics Data System (ADS)

    Archibald, A. T.; Cooke, M. C.; Utembe, S. R.; Shallcross, D. E.; Derwent, R. G.; Jenkin, M. E.

    2010-09-01

    Recently reported model-measurement discrepancies for the concentrations of the HOx radical species (OH and HO2) in locations characterized by high emission rates of isoprene have indicated possible deficiencies in the representation of OH recycling and formation in isoprene mechanisms currently employed in numerical models; particularly at low levels of NOx. Using version 3.1 of the Master Chemical Mechanism (MCM v3.1) as a base mechanism, the sensitivity of the system to a number of detailed mechanistic changes is examined for a wide range of NOx levels, using a simple box model. The studies consider sensitivity tests in relation to three general areas for which experimental and/or theoretical evidence has been reported in the peer-reviewed literature, as follows: (1) implementation of propagating channels for the reactions of HO2 with acyl and β-oxo peroxy radicals with HO2, with support from a number of studies; (2) implementation of the OH-catalysed conversion of isoprene-derived hydroperoxides to isomeric epoxydiols, as characterised by Paulot et al.~(2009a); and (3) implementation of a mechanism involving respective 1,5 and 1,6 H atom shift isomerisation reactions of the β-hydroxyalkenyl and cis-δ-hydroxyalkenyl peroxy radical isomers, formed from the sequential addition of OH and O2 to isoprene, based on the theoretical study of Peeters et al. (2009). All the considered mechanistic changes lead to simulated increases in the concentrations of OH, with (1) and (2) resulting in respective increases of up to about 7% and 16%, depending on the level of NOx. (3) is found to have potentially much greater impacts, with enhancements in OH concentrations of up to a factor of about 3.3, depending on the level of NOx, provided the (crucial) rapid photolysis of the hydroperoxy-methyl-butenal products of the cis-δ-hydroxyalkenyl peroxy radical isomerisation reactions is represented, as also postulated by Peeters et al.~(2009). Additional tests suggest that the

  11. Decadal- to biennial scale variability of planktic foraminifera in the northeastern Arabian Sea during the last two millennia: evidence for winter monsoon forcing mechanisms

    NASA Astrophysics Data System (ADS)

    Munz, Philipp; Lückge, Andreas; Siccha, Michael; Kucera, Michal; Schulz, Hartmut

    2015-04-01

    The Asian monsoon system is controlling the hydrologic cycle, and thus the agricultural and economic prosperity of the worlds most densely populated region. Strong and moisture-laden winds from the southwest induce upwelling and significant productivity in the western Arabian Sea during boreal summer. During boreal winter, weaker dry and cold surface winds from the northeast nourish ocean productivity mainly in the northeastern Arabian Sea. Instrumental records spanning the last century are too short to understand how the monsoon system reacts to external forcing mechanisms and to accurately determine its natural variability. Compared to the summer monsoon component, the dynamics of the winter monsoon are virtually unknown, due to the lack of adequate archives that are affected only by winter conditions. Here we present a decadal- to biennial-scale resolution record of past winter monsoon variability over the last two millennia, based on census counts of planktic foraminifera from two laminated sediment cores collected offshore Pakistan. One shorter box core (SO90-39KG) spans the last 250 years with an average ~2-year resolution, whereas the longer piston core (SO130-275KL) spans the last 2,100 years with a 10-year resolution. We use Globigerina falconensis as a faunal indicator for winter conditions, a species that is most abundant during winter in the NE Arabian Sea (Peeters and Brummer, 2002; Schulz et al., 2002). Our results show that during the past 2,100 years G. falconensis varied with significant periodicities centered on ˜ 60, ˜ 53, ˜ 40, ˜ 34 and ˜ 29 years per cycle. Some of these periods closely match cycles that are known from proxy records of solar irradiance, suggesting a solar forcing on winter monsoon variability. During the past 250 years G. falconensis varied in correlation with the (11-year) Schwabe and the (22-year) Hale solar cycles. Furthermore, a significant ˜ 7 year cyclicity could indicate a teleconnection to the El Niño Southern

  12. Hydroxyl radical regeneration in isoprene oxidation: upgraded mechanism LIM1

    NASA Astrophysics Data System (ADS)

    Peeters, Jozef; Son Nguyen, Vinh; Nguyen, Thanh Lam; Stravrakou, Trissevgeni; Muller, Jean-Francois

    2013-04-01

    The OH regeneration known to occur in isoprene oxidation at low/moderate NO is attributed in the Leuven Isoprene Mechanism to novel, theoretically characterized chemical pathways (LIM0: Peeters et al. 2009; Peeters and Muller 2010). Its key new features are (i) quasi-equilibration of the thermally labile beta-OH- and delta-OH-isoprenylperoxy isomers; (ii) 1,6-H shift isomerisation of the Z-delta-OH-peroxy isomers to yield hydroperoxy-methyl-butenals (HPALDs); (iii) fast photolysis of the HPALDs resulting overall in several OH radicals per HPALD. The OH-regeneration through photolabile HPALDs has recently found experimental support, but the peroxy isomerisation rate, HPALD yield and extent of OH recycling are still uncertain (Crounse et al. 2011; Wolfe et al. 2012). In this work, the upgraded LIM1 mechanism is presented. Based on much higher levels of theory that fully account for dispersion effects, the crucial equilibrium ratio of the isomerising Z-delta-OH-peroxys over the majority beta-OH-isoprenylperoxys is reduced by a factor ≈5 and the isomerisation rate of the Z-delta-OH-peroxys by a factor ≈1.5 compared to LIM0. The chemistry following the 1,6-H shift of the Z-delta-OH-peroxys is also much expanded and extended. Firstly, LIM1 introduces other pathways beside HPALD formation following the Z-delta-OH-peroxy isomerisation, but resulting likewise in OH recycling. This, together with the revised Z-delta-OH- equilibrium and isomerisation data above, affords a fair model-reproduction of the HPALD and other product yields observed by Crounse et al. (2011). Secondly, LIM1 proposes new fast reactions of HO2 with the alpha-oxoketene products from the peroxy isomerisation routes; these reactions are shown to efficiently convert HO2 into OH and are prime candidates for the unknown X + HO2 → OH + ... hydroxyl-recycling routes invoked in recent studies (Hofzumahaus et al.2009; Whalley et al. 2011). Modeling results using the IMAGES global CTM will be presented on

  13. HOx regeneration in the oxidation of isoprene III: theoretical study of the key isomerisation of the Z-δ-hydroxy-peroxy isoprene radicals.

    PubMed

    Nguyen, Thanh Lam; Vereecken, Luc; Peeters, Jozef

    2010-12-17

    As a sequel to our communication on a proposed new isoprene oxidation mechanism aiming to rationalize the unexpectedly high OH and HO(2) levels observed in isoprene-rich areas (J. Peeters, T. L. Nguyen, L. Vereecken, Phys. Chem. Chem. Phys. 2009, 11, 5935), we report herein the detailed quantum chemical and statistical kinetics characterization of the crucial 1,6-H shifts in the two Z-δ-hydroxy-peroxy radicals from isoprene. Geometries, energies and vibration frequencies of all conformers of the reactant radicals and transition states are computed at the B3LYP/6-31+G(d,p) level of theory and the energies of the lowest-lying conformers are then refined at various higher levels of theory, including CBS-QB3, IRCMax(CBS-QB3//B3LYP) and CBS-APNO. The rate coefficients over a wide temperature range are calculated using multi-conformer transition state theory with WKB tunneling factors evaluated for the barrier shape found by CBS-QB3//B3LYP IRC analyses. The WKB tunneling factors for these allyl-stabilisation-assisted reactions are about 25 at ambient temperatures. The rate coefficients can be represented by Arrhenius expressions over the 250-350 K range: k(T)=1.4×10(9) exp(-6380/T) s(-1) for the Z-1-OH-4-OO(·)-isoprene radical, and k(T)=0.72×10(9) exp(-5520/T) s(-1) for Z-1-OH-4-OO(·)-isoprene. With the k(1,6-H) of order 1 s(-1) at ambient temperatures, these isomerisations can compete with and even outrun the traditional peroxy reactions at low and moderate NO levels. The importance of these reactions as key processes in the newly proposed, OH-regenerating isoprene oxidation scheme is discussed.

  14. Pedagogy with babies: perspectives of eight nursery managers.

    PubMed

    Elfer, Peter; Page, Jools

    2015-12-02

    The last 30 years have seen a significant increase in babies attending nursery, with corresponding questions about the aims and organisation of practice. Research broadly agrees on the importance of emotionally consistent, sensitive and responsive interactions between staff and babies. Policy objectives for nursery and expectations of parents and staff give rise to different and sometimes conflicting aims for such interactions; for example attachments to staff, peer interactions or early learning. Research shows marked variations of pedagogy aims and organisation with babies in nurseries in different national and cultural contexts. It also demonstrates variation between nurseries in similar contexts and between staff in their beliefs and values about work with babies. This paper reports on an exploratory study of the beliefs, aspirations and approaches of eight managers concerning pedagogy with babies in two similar English local authorities. These managers spoke of the importance of being responsive to the concerns and priorities of parents, whilst being sensitive to the demands of the work on their staff. The main finding was of the contradictions and confusions managers felt were inherent in the work, arising from both conflicting policy objectives and personal beliefs and aspirations; sometimes their own and sometimes those of individual staff and parents. Urban, Vandenbroeck, Van Laere, Lazzari, and Peeters' [(2012). Towards competent systems in early childhood education and care. Implications for policy and practice. European Journal of Education, 47(4), 508-526.] concept of the 'competent system' is used to recommend a grounded approach to the development of a more culturally, socially and individually responsive pedagogy with babies than appears to exist at present.

  15. EDITORIAL: Special issue containing papers presented at the 4th IAEA Technical Meeting on the Theory of Plasma Instabilities Special issue containing papers presented at the 4th IAEA Technical Meeting on the Theory of Plasma Instabilities

    NASA Astrophysics Data System (ADS)

    Itoh, K.; Wilson, H. R.

    2010-05-01

    The 4th IAEA technical meeting (TM) on the Theory of Plasma Instabilities was held in Kyoto, May 18th--20th 2009, following the first (Seeon), second (Trieste) and third (York) meetings in this series. This IAEA-TM was motivated by the recent advances in theoretical methodology, the rapid progress in observations of laboratory and astrophysical plasmas and the evolution of fusion research as we approach the ITER era. The international advisory committee (IAC) and local organizing committee (LOC), the members of which are listed below, collaborated to define the scope and the content of the scientific programme. Young scientists were actively encouraged to participate in this TM to help stimulate their future research careers and raise their international profiles. Through these young scientists, the IAEA-TM planned to identify the future directions of research. About 90 researchers, from 13 countries and the IAEA, participated in this IAEA-TM, with 72 scientific presentations. The talks and posters generated enthusiastic discussions, contributing to the vibrancy of the meeting. This special issue of Nuclear Fusion consists of a cluster of papers, reporting some of the main contributions to the IAEA-TM. The articles in this cluster are representative of the scientific width of presentations at the meeting, spanning topics from micro-turbulence to large-scale MHD dynamics and from transport to detailed analysis of diagnostics. They demonstrate the quality and depth of the research presented at the conference. List of IAC (alphabetical order): B. Breizman (USA), S. Guenter (Germany), T. S. Hahm (USA), K. Itoh (Japan, Chair of 2009), Ya. I. Kolesnichenko (Ukraine), A. G. Peeters (UK), H. Wilson (UK) List of LOC (alphabetical order): A. Fukuyama, R. Horiuchi, S.-I. Itoh, N. Kasuya, Y. Kishimoto (co-chair), K. Kusano, J. Li, K. Mima, S. Murakami, H. Naitou, N. Nakajima, Y. Nakamura, H. Ohtani, S. Okamura, T. Ozeki, S. Sudo (co-chair), H. Sugama, Y. Todo, S. Tokuda, S

  16. Large effect of irradiance on hydrogen isotope fractionation of alkenones in Emiliania huxleyi

    NASA Astrophysics Data System (ADS)

    van der Meer, Marcel T. J.; Benthien, Albert; French, Katherine L.; Epping, Eric; Zondervan, Ingrid; Reichart, Gert-Jan; Bijma, Jelle; Sinninghe Damsté, Jaap S.; Schouten, Stefan

    2015-07-01

    The hydrogen isotopic (δD) composition of long-chain alkenones produced by certain haptophyte algae has been suggested as a potential proxy for reconstructing paleo sea surface salinity. However, environmental parameters other than salinity may also affect the δD of alkenones. We investigated the impact of the level of irradiance on hydrogen isotopic fractionation of alkenones versus growth water by cultivating two strains of the cosmopolitan haptophyte Emiliania huxleyi at different light intensities. The hydrogen isotope fractionation decreased by approximately 40‰ when irradiance was increased from 15 to 200 μmol photons m-2 s-1 above which it was relatively constant. The response is likely a direct effect of photosystem I and II activity as the relationship of the fractionation factor α versus light intensity can be described by an Eilers-Peeters photosynthesis model. This irradiance effect is in agreement with published δD data of alkenones derived from suspended particulate matter collected from different depths in the photic zone of the Gulf of California and the eastern tropical North Pacific. However, haptophyte algae tend to bloom at relatively high light intensities (>500 μmol photons m-2 s-1) occurring at the sea surface, at which hydrogen isotope fractionation is relatively constant and not affected by changes in light intensity. Alkenones accumulating in the sediment are likely mostly derived from these surface water haptophyte blooms, when the largest amount of biomass is produced. Therefore, the observed irradiance effect is unlikely to affect the applicability of the hydrogen isotopic composition of sedimentary long chain alkenones as a proxy for paleosalinity.

  17. Perturbative studies of toroidal momentum transport using neutral beam injection modulation in the Joint European Torus: Experimental results, analysis methodology, and first principles modeling

    SciTech Connect

    Mantica, P.; Ferreira, J. S.; Salmi, A.; Strintzi, D.; Weiland, J.; Brix, M.; Giroud, C.; Corrigan, G.; Zastrow, K.-D.; Tardini, G.

    2010-09-15

    Perturbative experiments have been carried out in the Joint European Torus [Fusion Sci. Technol. 53(4) (2008)] in order to identify the diffusive and convective components of toroidal momentum transport. The torque source was modulated either by modulating tangential neutral beam power or by modulating in antiphase tangential and normal beams to produce a torque perturbation in the absence of a power perturbation. The resulting periodic perturbation in the toroidal rotation velocity was modeled using time-dependent transport simulations in order to extract empirical profiles of momentum diffusivity and pinch. Details of the experimental technique, data analysis, and modeling are provided. The momentum diffusivity in the core region (0.2<{rho}<0.8) was found to be close to the ion heat diffusivity ({chi}{sub {phi}/{chi}i{approx}}0.7-1.7) and a significant inward momentum convection term, up to 20 m/s, was found, leading to an effective momentum diffusivity significantly lower than the ion heat diffusivity ({chi}{sub {phi}}{sup eff}/{chi}{sub i}{sup eff{approx}}0.4). These results have significant implications on the prediction of toroidal rotation velocities in future tokamaks and are qualitatively consistent with recent developments in momentum transport theory. Detailed quantitative comparisons with the theoretical predictions of the linear gyrokinetic code GKW [A. G. Peeters et al., Comput. Phys. Commun. 180, 2650 (2009)] and of the quasilinear fluid Weiland model [J. Weiland, Collective Modes in Inhomogeneous Plasmas (IOP, Bristol, 2000)] are presented for two analyzed discharges.

  18. Pedagogy with babies: perspectives of eight nursery managers

    PubMed Central

    Elfer, Peter; Page, Jools

    2015-01-01

    The last 30 years have seen a significant increase in babies attending nursery, with corresponding questions about the aims and organisation of practice. Research broadly agrees on the importance of emotionally consistent, sensitive and responsive interactions between staff and babies. Policy objectives for nursery and expectations of parents and staff give rise to different and sometimes conflicting aims for such interactions; for example attachments to staff, peer interactions or early learning. Research shows marked variations of pedagogy aims and organisation with babies in nurseries in different national and cultural contexts. It also demonstrates variation between nurseries in similar contexts and between staff in their beliefs and values about work with babies. This paper reports on an exploratory study of the beliefs, aspirations and approaches of eight managers concerning pedagogy with babies in two similar English local authorities. These managers spoke of the importance of being responsive to the concerns and priorities of parents, whilst being sensitive to the demands of the work on their staff. The main finding was of the contradictions and confusions managers felt were inherent in the work, arising from both conflicting policy objectives and personal beliefs and aspirations; sometimes their own and sometimes those of individual staff and parents. Urban, Vandenbroeck, Van Laere, Lazzari, and Peeters' [(2012). Towards competent systems in early childhood education and care. Implications for policy and practice. European Journal of Education, 47(4), 508–526.] concept of the ‘competent system’ is used to recommend a grounded approach to the development of a more culturally, socially and individually responsive pedagogy with babies than appears to exist at present. PMID:26692633

  19. HOx regeneration in isoprene oxidation: evidence for new unimolecular peroxy radical reactions with strong implications for tropospheric chemistry

    NASA Astrophysics Data System (ADS)

    Peeters, Jozef; Nguyen, Thanh Lam; Vereecken, Luc; Muller, Jean-Francois

    2010-05-01

    HOx re-generation in the oxidation of isoprene, with its global emissions of about 500 Tg/yr, has a large impact on the global oxidizing capacity of the atmosphere. Recently, we proposed and theoretically quantified new pathways for the OH-initiated oxidation of isoprene that might explain the much higher than observed OH concentrations in isoprene-rich environments (Peeters et al., Phys.Chem.Chem.Phys., 11, 5935, 2009). The new reaction mechanisms put forward and characterized using high-level theoretical methods include (i) the very fast interconversion (by O2 elimination and addition) of the various conformers/isomers of the major isoprene peroxy radicals, (ii) the 1,5-H shift of the major β-OH-peroxys generating OH with coproducts MACR or MACR, and most importantly, (iii) the 1,6-H shift of specific conformers (Z-δ-OH-peroxys) followed by reaction with O2 generating HO2 and very photolabile hydroperoxy aldehydes (denoted HPALDs), and (iv) fast photolysis (with quantum yield approaching unity) as the main sink of the HPALDs, generating OH and a radical which will give rise to additional OH formation. In this communication we present evidence, from recent experimental observations, for the newly proposed chemistry. The yields of the main first-generation products (HOx, HPALD, MVK, MACR, but also the hydroxy-aldehydes HALD) will be examined as a function of NO. The implications regarding the role of isoprene in the atmosphere will be also briefly discussed. A global modelling study aiming at quantifying the impact of the new chemistry will be presented in a companion paper in this session.

  20. Unusually fast 1,6-h shifts of enolic hydrogens in peroxy radicals: formation of the first-generation C2 and C3 carbonyls in the oxidation of isoprene.

    PubMed

    Peeters, Jozef; Nguyen, Thanh Lam

    2012-06-21

    In a theoretical investigation using the CBS-QB3//UB3LYP/6-31+G** method supported by higher-level computations such as CBS-QB3//UQCISD/6-31+G**, the 1,6-H shifts of the enolic hydrogen in peroxy radicals of the type Z-HO-CH═CH-CH(2)-OO(•) were found to face exceptionally low energy barriers of only about 11 kcal mol(-1)--i.e., 6-9 kcal mol(-1) lower than the barriers for similar shifts of alkane hydrogens--such that they can proceed at unequaled rates of order 10(5) to 10(6) s(-1) at ambient temperatures. The unusually low barriers for enolic 1,6-H shifts in peroxy radicals, characterized here for the first time to our knowledge, are rationalized. As cases in point, the secondary peroxy radicals Z-HO-CH═C(CH(3))-CH(OO(•))-CH(2)OH (case A) and Z-HO-CH═CH-C(CH(3))(OO(•))-CH(2)OH (case B) derived from the primary Z-δ-hydroxy-peroxy radicals in the oxidation of isoprene, are predicted to undergo 1,6-H shifts of their enolic hydrogens at TST-calculated rates in the range 270-320 K of k(T)(A) = 5.4 × 10(-4) × T(5.04) × exp(-1990/T) s(-1) and k(T)(B) = 109 × T(3.13) × exp(-3420/T) s(-1), respectively, i.e., 2.0 × 10(6) and 6.2 × 10(4) s(-1), respectively, at 298 K, far outrunning in all relevant atmospheric and laboratory conditions their reactions with NO proposed earlier as their dominant pathways (Dibble J. Phys. Chem. A 2004, 108, 2199). These fast enolic-H shifts are shown to provide the explanation for the first-generation formation of methylglyoxal + glycolaldehyde, and glyoxal + hydroxyacetone in the oxidation of isoprene under high-NO conditions, recently determined by several groups. However, under moderate- and low-NO atmospheric conditions, the fast interconversion and equilibration of the various thermally labile, initial peroxy conformers/isomers from isoprene and the isomerization of the initial Z-δ-hydroxy-peroxy radicals, both recently proposed by us (Peeters et al. Phys. Chem. Chem. Phys. 2009, 11, 5935), are expected to

  1. Combining Ambient Measurements of OH Radicals and OH Reactivity in a Tropical Rainforest during the OP-3 Project: Resolving the Magnitude of the Missing OH Sources and Sinks

    NASA Astrophysics Data System (ADS)

    Whalley, L. K.; Edwards, P.; Furneaux, K. L.; Goddard, A.; George, I. J.; Evans, M. J.; Heard, D. E.; Team Op-3

    2010-12-01

    effect of 0.74 ppbv of NO. The model is unable to account for all of the OH reactivity; to simulate the OH reactivity a range of unmeasured sinks must be invoked. In general we believe that the simultaneous measurement of OH reactivity and OH concentration enables the separation of OH sources and sinks, allowing a more comprehensive test of our understanding of the radical chemistry occurring in this chemically complex environment. [1] J. Lelieveld, T. M. Butler, J. N. Crowley et al.: Nature, 2008, 452, p.737 - 740 [2] J. Peeters, T. L. Nguyen & L. Vereecken, PCCP, 2009, 11, p.5935 - 5939

  2. Comparisons of observed and modeled OH and HO2 concentrations during the ambient measurement period of the HOxComp field campaign

    NASA Astrophysics Data System (ADS)

    Kanaya, Y.; Hofzumahaus, A.; Dorn, H.-P.; Brauers, T.; Fuchs, H.; Holland, F.; Rohrer, F.; Bohn, B.; Tillmann, R.; Wegener, R.; Wahner, A.; Kajii, Y.; Miyamoto, K.; Nishida, S.; Watanabe, K.; Yoshino, A.; Kubistin, D.; Martinez, M.; Rudolf, M.; Harder, H.; Berresheim, H.; Elste, T.; Plass-Dülmer, C.; Stange, G.; Kleffmann, J.; Elshorbany, Y.; Schurath, U.

    2012-03-01

    A photochemical box model constrained by ancillary observations was used to simulate OH and HO2 concentrations for three days of ambient observations during the HOxComp field campaign held in Jülich, Germany in July 2005. Daytime OH levels observed by four instruments were fairly well reproduced to within 33% by a base model run (Regional Atmospheric Chemistry Mechanism with updated isoprene chemistry adapted from Master Chemical Mechanism ver. 3.1) with high R2 values (0.72-0.97) over a range of isoprene (0.3-2 ppb) and NO (0.1-10 ppb) mixing ratios. Daytime HO2(*) levels, reconstructed from the base model results taking into account the sensitivity toward speciated RO2 (organic peroxy) radicals, as recently reported from one of the participating instruments in the HO2 measurement mode, were 93% higher than the observations made by the single instrument. This also indicates an overprediction of the HO2 to OH recycling. Together with the good model-measurement agreement for OH, it implies a missing OH source in the model. Modeled OH and HO2(*) could only be matched to the observations by addition of a strong unknown loss process for HO2(*) that recycles OH at a high yield. Adding to the base model, instead, the recently proposed isomerization mechanism of isoprene peroxy radicals (Peeters and Müller, 2010) increased OH and HO2(*) by 28% and 13% on average. Although these were still only 4% higher than the OH observations made by one of the instruments, larger overestimations (42-70%) occurred with respect to the OH observations made by the other three instruments. The overestimation in OH could be diminished only when reactive alkanes (HC8) were solely introduced to the model to explain the missing fraction of observed OH reactivity. Moreover, the overprediction of HO2(*) became even larger than in the base case. These analyses imply that the rates of the isomerization are not readily supported by the ensemble of radical observations. One of the measurement days

  3. Evaluating the Effect of Labeled Benchmarks on Children's Number Line Estimation Performance and Strategy Use.

    PubMed

    Peeters, Dominique; Sekeris, Elke; Verschaffel, Lieven; Luwel, Koen

    2017-01-01

    Some authors argue that age-related improvements in number line estimation (NLE) performance result from changes in strategy use. More specifically, children's strategy use develops from only using the origin of the number line, to using the origin and the endpoint, to eventually also relying on the midpoint of the number line. Recently, Peeters et al. (unpublished) investigated whether the provision of additional unlabeled benchmarks at 25, 50, and 75% of the number line, positively affects third and fifth graders' NLE performance and benchmark-based strategy use. It was found that only the older children benefitted from the presence of these benchmarks at the quartiles of the number line (i.e., 25 and 75%), as they made more use of these benchmarks, leading to more accurate estimates. A possible explanation for this lack of improvement in third graders might be their inability to correctly link the presented benchmarks with their corresponding numerical values. In the present study, we investigated whether labeling these benchmarks with their corresponding numerical values, would have a positive effect on younger children's NLE performance and quartile-based strategy use as well. Third and sixth graders were assigned to one of three conditions: (a) a control condition with an empty number line bounded by 0 at the origin and 1,000 at the endpoint, (b) an unlabeled condition with three additional external benchmarks without numerical labels at 25, 50, and 75% of the number line, and (c) a labeled condition in which these benchmarks were labeled with 250, 500, and 750, respectively. Results indicated that labeling the benchmarks has a positive effect on third graders' NLE performance and quartile-based strategy use, whereas sixth graders already benefited from the mere provision of unlabeled benchmarks. These findings imply that children's benchmark-based strategy use can be stimulated by adding additional externally provided benchmarks on the number line, but that

  4. Modulation of the Substitution Pattern of 5-Aryl-2-Aminoimidazoles Allows Fine-Tuning of Their Antibiofilm Activity Spectrum and Toxicity.

    PubMed

    Peeters, Elien; Hooyberghs, Geert; Robijns, Stijn; Waldrant, Kai; De Weerdt, Ami; Delattin, Nicolas; Liebens, Veerle; Kucharíková, Soňa; Tournu, Hélène; Verstraeten, Natalie; Dovgan, Barbara; Girandon, Lenart; Fröhlich, Mirjam; De Brucker, Katrijn; Van Dijck, Patrick; Michiels, Jan; Cammue, Bruno P A; Thevissen, Karin; Vanderleyden, Jozef; Van der Eycken, Erik; Steenackers, Hans P

    2016-11-01

    antibiofilm activity spectrum and toxicity. Copyright © 2016 Peeters et al.

  5. EVAPORISATION: a new vapor pressure model taking into account neighbour effects

    NASA Astrophysics Data System (ADS)

    Compernolle, Steven; Ceulemans, Karl; Muller, Jean-Francois

    2010-05-01

    pressure method can have a major impact on aerosol yield, considerably larger than the choice of activity coefficient model (Compernolle et al. 2009). M. Capouet and J.-F. Muller, Atm. Chem. Phys. 6, 1455-1467 (2006) M. Capouet, J.-F. Muller, K. Ceulemans, S. Compernolle, L. Vereecken and J. Peeters, J. Geophys. Res. 113, D02308 (2008) S. Compernolle, K. Ceulemans and J. Muller, Atm. Chem. Phys. 9, 1325-1388 (2009) S.H. Hilal, S.W. Karickhoff and L.A. Carreira , QSAR Comb. Sci. 22, 565-574 (2003) P.B. Myrdal and S.H. Yalkowsky, Ind. Eng. Chem. Res. 36, 2494-2499 (1997) Y. Nannoolal, J. Rarey and D. Ramjugernath, Fluid Phase Eq. 269, 117-133 (2008) B. Moller, J. Rarey and D. Ramjugernath, J. Mol. Liq. 143, 52-63 (2008)

  6. Micro Flow Cytometry Miniaturisation - Towards in-situ Optical Phytoplankton Analysis

    NASA Astrophysics Data System (ADS)

    Zmijan, R.; Abi Kaed Bey, S.; Mowlem, M. C.; Morgan, H.

    2012-04-01

    The use of flow cytometry for studies of temporal and spatial variability of phytoplankton populations is a valuable tool contributing to research relating carbon biogeochemistry and climate change. Early designs and marine deployments of such devices started over two decades ago [1-3]. Miniaturisation and cost reduction without sacrificing performance remains a major challenge but would enable mass production and deployment. Large numbers of measurement nodes (e.g. as part of a global ocean observation system) would be possible which would increase data available over both spatial and temporal scales. This research presents two different design approaches for miniaturisation and integration of optics into a microfluidic cytometer chip. The proposed solutions are suitable for micro cytometers with external components coupled with optical fibres and were simulated and optimised using ray tracing software (Zemax). The two designs address light delivery for excitation of particles within the measurement region of the cytometer. One uses an integrated micro lens (fabricated in the chip) and the other a ball shaped micro lens manufactured separately and then inserted into the chip. Both approaches collimate the excitation light beam (from an off chip diode laser coupled with an optical fibre) into the fluidic channel. The predicted (by ray tracing) excitation beam widths are 70 and 80 µm for the integrated and the ball lens respectively, and are in agreement with experimental data presented. The proposed cytometer chip design is compatible with low cost materials (acrylic glass, cyclo-olefines) and manufacturing methods (micro milling, hot embossing, injection moulding). 1. Dubelaar, G.B.J. and P.L. Gerritzen, CytoBuoy: a step forward towards using flow cytometry in operational oceanography. Scientia Marina, 2000. 64(2): p. 255-265. 2. Peeters, J.C.H., et al., Optical Plankton Analyzer - a Flow Cytometer for Plankton Analysis .1. Design Considerations. Cytometry, 1989

  7. Spectroscopy and photometric flux correlations for a sample of AGNs in the range of 4 ×10^3-25 ×10^4Å

    NASA Astrophysics Data System (ADS)

    Higuera G., M. A.; Rodríguez-Ardila, A.; Tejeiro, J. M.

    2006-06-01

    The Active Galactic Nuclei (AGN) unified theory says that the primary role of a dusty torus around a central AGN is to hide the central engine. Nowdays based on near-infrared spectroscopy L-band spectroscopy and data collected from ground and space-based observatories is possible to explore the occurrence of starbursts in the dusty torus (Imanishi et al. 2004). Because the torus is rich in dust and molecular gas, it is a natural place to the ocurrence of starburts activity. The detection of PAH emission from the inner tens of parsecs in several Seyfert sources (Imanishi 2003; Rodríguez-Ardila et al. 2004; Peeters et al. 2004), suggest that the PAH detected emission can be directly associated to star formation episodes in the torus structure. The main goal of this work is to test the above hypothesis by means of flux correlations between the PAHs emission lines and the optical-infrared continuum using the data available in the literature. For a subset of galaxies from the CfA sample we choose continuum flux measurements at the wavelengths 0.6μm, 1.6μm, 2.1μm, 3.5μm (Alonso-Herrero et al. 2003), and 12μm, 25μm (Imanishi 2003, 2004). For our analysis, we selected the ratios F1.6/F3.3, F2.1/F3.3, F12/F3.3 and F25/F3.3 as a function of FOpt/F3.3, and F3.5/F3.3. We found a good correlation between F1.6/F.3.3 vs. FOpt/F3.3 and F2.1/F3.3 vs F3.5/F3.3, however in the other cases the correlations are not so good. The values observed show the presence of dust emission and reddening. In order to refine our study, new relationships need to be established, for example, between the 3.3μm and the other PAH emission lines with: radio emission (1.49); emission from molecular hydrogen H_2 (2.121μm), Brγ (2.165μm) and emissions in the range of soft and hard X-rays.

  8. Ambient measurements of OH and OH reactivity during the OP3 project: Resolving the magnitude of the missing OH source

    NASA Astrophysics Data System (ADS)

    Whalley, L. K.; Furneaux, K.; Edwards, P.; Goddard, A.; Heard, D. E.

    2012-12-01

    and has wide implications, leading to much higher predicted OH over tropical forests, with a concomitant reduction in the methane lifetime and increase in the rate of VOC degradation [4]. [1] Bloss, W. J. et al., Faraday Discuss. 130, 425-436, 2005 [2] Lelieveld, J et al., Journal of Geophysical Research - Atmospheres, 107, 4715, 2002 [3] Peeters, J. et al., Physical Chemistry Chemical Physics, 28, 5935-5939, 2009 [4] Whalley, L. K. et al., Atmospheric Chemistry and Physics, 11, 7223-7233, 2011

  9. Effects of climate change on deep-water oxygen and winter mixing in a deep lake (Lake Geneva)

    NASA Astrophysics Data System (ADS)

    Schwefel, Robert; Alfred, Wüest; Damien, Bouffard

    2016-04-01

    Oxygen is the most important dissolved gas for lake ecosystems. Because low oxygen concentrations are an ongoing problem in many parts of the oceans and numerous lakes, oxygen depletion processes have been intensively studied over the last decades and were mainly attributed to high nutrient loads. Recently, climate-induced changes in stratification and mixing behavior were recognized as additional thread to hypolimnetic oxygen budgets in lakes and reservoirs [Matzinger et al., 2007; Zhang et al., 2015]. Observational data of Lake Geneva, a deep perialpine lake situated between France and Switzerland showed no decreasing trend in hypoxia over the last 43 years, despite an impressive reduction in nutrient input during this period. Instead, hypoxic conditions were predominantly controlled by deep mixing end of winter and in turn by winter temperatures. To test the sensitivity of Lake Geneva on future climate change and changes in water transparency, we simulated the hydrodynamics and temperature of Lake Geneva under varying conditions for atmospheric temperature and water clarity performed with the one-dimensional model SIMSTRAT [Goudsmit, 2002]. The results show, that the stratification in lakes is only weakly affected by changes in light absorption due to varying water quality. For conditions expected for the end of the century, a decrease in the annual mean deep convective mixing of up to 45 m is predicted. Also complete mixing events over the whole lake are less likely to occur. A change in the hypolimnetic oxygen concentration of up to 20% can thus be expected in the future. These results show, that changes in deep mixing have an equally strong impact as eutrophication on the deep-water oxygen development of oligomictic lakes and have to be considered in the prediction of the future development of lakes. References: Goudsmit, G. H., H. Burchard, F. Peeters, and A. Wüest (2002), Application of k-ɛ turbulence models to enclosed basins: The role of internal

  10. Using noble gases in the pore water of ocean sediments to characterize CH4 seepage off the coast of New Zealand

    NASA Astrophysics Data System (ADS)

    Tomonaga, Yama; Brennwald, Matthias S.; Kipfer, Rolf

    2013-04-01

    Newly developed analytical techniques to determine the abundances of noble gases in sediment pore water [1, 5] allow noble-gas concentrations and isotope ratios to be measured easily and routinely in unconsolidated lacustrine sediments [6, 7]. We applied these techniques for the first time to ocean sediments to investigate an active cold methane seepage system located in the South Pacific off the coast of New Zealand using 3He-4He ratios determined in the sediment pore water. Our results [8] show that more 3He-rich fluids are released in the vicinity of the Pacific-Australian subduction zone than at the forearc stations located closer to the New Zealand coast. However, the 3He-4He isotope signature in the sediment column indicates that only a minor part of the He emanating from deeper strata originates from a (depleted) mantle source. Hence, most He in the pore water is produced locally by the radioactive decay of U and Th in the sediment minerals or in the underlying crustal rocks. Such an occurrence of isotopically heavy crustal He also suggests that the source of the largest fraction of methane is a near-surface geochemical reservoir. This finding is in line with a previous δ13C study in the water column which concluded that the emanating methane is most likely of biological origin and is formed in the upper few meters of the sediment column [2]. The prevalence of isotopically heavy He agrees well with the outcome of other previous studies on island arc systems [3, 4] which indicate that the forearc regions are characterized by crustal He emission, whereas the volcanic arc region is characterized by the presence of mantle He associated with rising magma. References [1] Brennwald, M. S., Hofer, M., Peeters, F., Aeschbach-Hertig, W., Strassmann, K., Kipfer, R., and Imboden, D. M. (2003). Analysis of dissolved noble gases in the pore water of lacustrine sediments. Limnol. Oceanogr.: Methods 1, 51-62. [2] Faure, K., Greinert, J., Schneider von Deimling, J., Mc

  11. Natural-Cause Mortality and Long-Term Exposure to Particle Components: An Analysis of 19 European Cohorts within the Multi-Center ESCAPE Project

    PubMed Central

    Hoek, Gerard; Raaschou-Nielsen, Ole; Stafoggia, Massimo; Andersen, Zorana Jovanovic; Weinmayr, Gudrun; Hoffmann, Barbara; Wolf, Kathrin; Samoli, Evangelia; Fischer, Paul H.; Nieuwenhuijsen, Mark J.; Xun, Wei W.; Katsouyanni, Klea; Dimakopoulou, Konstantina; Marcon, Alessandro; Vartiainen, Erkki; Lanki, Timo; Yli-Tuomi, Tarja; Oftedal, Bente; Schwarze, Per E.; Nafstad, Per; De Faire, Ulf; Pedersen, Nancy L.; Östenson, Claes-Göran; Fratiglioni, Laura; Penell, Johanna; Korek, Michal; Pershagen, Göran; Eriksen, Kirsten Thorup; Overvad, Kim; Sørensen, Mette; Eeftens, Marloes; Peeters, Petra H.; Meliefste, Kees; Wang, Meng; Bueno-de-Mesquita, H. Bas; Sugiri, Dorothea; Krämer, Ursula; Heinrich, Joachim; de Hoogh, Kees; Key, Timothy; Peters, Annette; Hampel, Regina; Concin, Hans; Nagel, Gabriele; Jaensch, Andrea; Ineichen, Alex; Tsai, Ming-Yi; Schaffner, Emmanuel; Probst-Hensch, Nicole M.; Schindler, Christian; Ragettli, Martina S.; Vilier, Alice; Clavel-Chapelon, Françoise; Declercq, Christophe; Ricceri, Fulvio; Sacerdote, Carlotta; Galassi, Claudia; Migliore, Enrica; Ranzi, Andrea; Cesaroni, Giulia; Badaloni, Chiara; Forastiere, Francesco; Katsoulis, Michail; Trichopoulou, Antonia; Keuken, Menno; Jedynska, Aleksandra; Kooter, Ingeborg M.; Kukkonen, Jaakko; Sokhi, Ranjeet S.; Vineis, Paolo; Brunekreef, Bert

    2015-01-01

    , Pershagen G, Eriksen KT, Overvad K, Sørensen M, Eeftens M, Peeters PH, Meliefste K, Wang M, Bueno-de-Mesquita HB, Sugiri D, Krämer U, Heinrich J, de Hoogh K, Key T, Peters A, Hampel R, Concin H, Nagel G, Jaensch A, Ineichen A, Tsai MY, Schaffner E, Probst-Hensch NM, Schindler C, Ragettli MS, Vilier A, Clavel-Chapelon F, Declercq C, Ricceri F, Sacerdote C, Galassi C, Migliore E, Ranzi A, Cesaroni G, Badaloni C, Forastiere F, Katsoulis M, Trichopoulou A, Keuken M, Jedynska A, Kooter IM, Kukkonen J, Sokhi RS, Vineis P, Brunekreef B. 2015. Natural-cause mortality and long-term exposure to particle components: an analysis of 19 European cohorts within the Multi-Center ESCAPE Project. Environ Health Perspect 123:525–533; http://dx.doi.org/10.1289/ehp.1408095 PMID:25712504

  12. Influences of the Agulhas Current on South African terrestrial climate as inferred from speleothem stable isotope records

    NASA Astrophysics Data System (ADS)

    Braun, K.; Bar-Matthews, M.; Ayalon, A.; Marean, C.; Herries, A. I. R.; Zahn, R.; Matthews, A.

    2012-04-01

    Basin[5,6] as well as an ice-core record from Antarctica[7] reveal that the speleothem δ18O and δ13C are more closely related to the sea surface temperature shifts in the Agulhas region and Antarctica (with lower δ18O and δ13C values corresponding to higher temperatures) than to the influence of global ice-volume related changes in the isotopic composition of the ocean. A contemporary record from a cave site situated ~92 km inland from Mossel Bay (E-Flux Cave, Klein Karoo) shows a very different signal, corresponding to overall changes in Obliquity[8]. The influence of the Agulhas Current is thus apparent on the coast, but reduced inland. [1] Bar-Matthews, M. et al. 2010. Quaternary Science Reviews 29 p2131. [2] Braun, K. et al. 2011. Conference Abstract, Climate Change - The Karst Record 6. Birmingham England p27. [3] Chase, B. M. & Meadows, M. E., 2007. Earth-Science Reviews 84 p103. [4] Cortese, G. et al. 2004. Earth and Planetary Science Letters 222 p767. [5] Martínez-Méndez, G. et al. (2010). Paleoceanography 25(PA4227): doi:10.1029/2009PA001879. [6] Peeters, F. J. C. et al. 2004. Nature 430 p661. [7] Petit, J. R. et al. 1999. Nature 399 p429. [8] Berger, A. L. 1978. Quaternary Research 9 p139.

  13. Re-visiting the Globigerinoides ruber δ18O salinity temperature relationship in the Indian Ocean

    NASA Astrophysics Data System (ADS)

    Saraswat, R.; Naik, D. K.; Nigam, R.; Mackensen, A.

    2013-12-01

    The stable oxygen isotopic ratio of surface dwelling planktic foraminifera Globigerinoides ruber ( δ18Oruber) combined with independent temperature reconstructions provides good estimate of hydrological changes over the geologic past. The application of δ18Oruber to assess hydrological changes, however requires precise understanding of the relationship between seawater temperature, salinity, pH, carbonate ion concentration and δ18Oruber. The digenetic changes, further complicate the application of δ18Oruber to assess past climatic conditions. Here we assess the δ18Oruber-seawater salinity-temperature relationship and effect of digenesis on this relationship in the northern Indian Ocean based on core-top samples. The samples were collected from two salinity end member regions in the path of seasonal coastal currents, in the northern Indian Ocean. The northeastern Bay of Bengal samples are from the lowest salinity region while those from the southeastern Arabian Sea are located at the distal end up to which low salinity Bay of Bengal water intrudes into the Arabian Sea. The δ18Oruber analyzed as part of this work were augmented with previous core-top δ18O measurements in the northern Indian Ocean. A total of ~325 surface sediment data points (97 from this work and 228 from previous work) are used to understand factors that affect δ18Oruber in the Indian Ocean. In order to understand the digenetic effect, the core-top δ18Oruber values were also compared with the previously published plankton tow δ18Oruber values from the Indian Ocean (Duplessy et al., 1981; Kroon and Ganssen, 1989; Ganssen and Kroon, 1991; Peeters et al., 2002), as well as the expected δ18O calculated from the modern seawater parameters (SST, SSS, δ18Osw). We report that salinity exerts the major control on δ18Oruber (R = 0.85), than temperature (R = 0.53). The δ18Osw estimated from the core-top δ18Oruber suggests 0.24‰ change per salinity unit which is close to previous reports but

  14. Electrical control of spin in topological insulators

    NASA Astrophysics Data System (ADS)

    Chang, Kai

    2012-02-01

    by changing the gate voltage. It provides us a new way to control surface magnetism electrically. The gap opened by doped magnetic ions can lead to a short-range Bloembergen-Rowland interaction. The competition among the Heisenberg, Ising, and DM terms leads to rich spin configurations and an anomalous Hall effect on different lattices [4]. There are many proposals for quantum computation scheme are based on the spin in semiconductor quantum dots. Topological insulator quantum dots display a very different behavior with that of conventional semiconductor quantum dots [5]. In sharp contrast to conventional semiconductor quantum dots, the quantum states in the gap of the HgTe QD are fully spin-polarized and show ring-like density distributions near the boundary of the QD and optically dark. The persistent charge currents and magnetic moments, i.e., the Aharonov-Bohm effect, can be observed in such a QD structure. This feature offers us a practical way to detect these exotic ring-like edge states by using the SQUID technique. [0pt]Refs: [1] W. Yang, Kai Chang, and S. C. Zhang, Phys. Rev. Lett. 100, 056602 (2008); J. Li and Kai Chang, Appl. Phys. Lett. 95, 222110 (2009). [2] L. B. Zhang, Kai Chang, X. C. Xie, H. Buhmann and L. W. Molenkamp, New J. Phys. 12, 083058 (2010). [3] L. B. Zhang, F. Cheng, F. Zhai and Kai Chang, Phys. Rev. B 83 081402(R) (2011); Z. H. Wu, F. Zhai, F. M. Peeters, H. Q. Xu and Kai Chang, Phys, Rev. Lett. 106, 176802 (2011). [4] J. J. Zhu, D. X. Yao, S. C. Zhang, and Kai Chang, Phys. Rev. Lett. 106, 097201 (2011). [5] Kai Chang, and Wen-Kai Lou, Phys. Rev. Lett. 106, 206802 (2011).

  15. EDITORIAL: Focus on Graphene

    NASA Astrophysics Data System (ADS)

    Peres, N. M. R.; Ribeiro, Ricardo M.

    2009-09-01

    lattice models and quantum spin chains Mahdi Zarea and Nancy Sandler On the universal ac optical background in graphene V P Gusynin, S G Sharapov and J P Carbotte Heat conduction in graphene: experimental study and theoretical interpretation S Ghosh, D L Nika, E P Pokatilov and A A Balandin Calculation of the Raman G peak intensity in monolayer graphene: role of Ward identities D M Basko Electronic transport in bilayer graphene Mikito Koshino Magnetic Kronig-Penney model for Dirac electrons in single-layer graphene M Ramezani Masir, P Vasilopoulos and F M Peeters Electrical transport in high-quality graphene pnp junctions Jairo Velasco Jr, Gang Liu, Wenzhong Bao and Chun Ning Lau Local density of states and scanning tunneling currents in graphene N M R Peres, Ling Yang and Shan-Wen Tsai Gaps and tails in graphene and graphane B Dóra and K Ziegler Quasi-ferromagnet spintronics in the graphene nanodisc-lead system Motohiko Ezawa Range and correlation effects in edge disordered graphene nanoribbons Alessandro Cresti and Stephan Roche Remarks on the tight-binding model of graphene Cristina Bena and Gilles Montambaux

  16. Fullerenes, Organics and the Diffuse Interstellar Bands

    NASA Astrophysics Data System (ADS)

    Foing, Bernard H.

    2016-07-01

    ; [12] Krelowski, J. et al. 1999A&A 347, 235; [13] Sonnentrucker, P., Cami, J., Ehrenfreund, P., Foing, B. H. 1997 A&A 327, 1215; [14] Sonnentrucker, P., Foing, B. H., Breitfellner, M., Ehrenfreund, P. 1999 A&A 346, 936; [15] Cox, N. et al. 2007 A&A 470, 941; [16] Ehrenfreund, P. et al. 2002 ApJ 576 L117; [17] Ehrenfreund, P.; Foing, B. H. 1996 A&A 307 L25; [18] Sarre, P. J. et al. 1995 MNRAS.277 L41; [19] Cossart-Magos, C. & Leach, S. 1990 A&A 233, 559; [20] Cox, N. L., Ehrenfreund, P., Foing, B. H. et al. 2011 A&A 531, 25; [21] Cox, N. L., Boudin, N., Foing, B. H. et al. 2007 A&A 465, 899; [22] Ehrenfreund, P. & Charnley, S. 2000 ANRAA 38, 427; [23] Scarrott, S. M., Watkin, S., Miles, J. R., Sarre, P. J. 1992 MNRAS 255, 11; [25] Planck Collaboration, 2011 A&A 536 20 (Planck early results. XX.); [26] Ehrenfreund, P. et al. 1995 A&A 299; 213; [27] Ehrenfreund, P. & Foing, B. H 1995 P&SS 43, 1183; [28] van der Zwet, G. P., Allamandola, L. J. 1985 A&A 146 76; [29] Salama, F. et al. 1996 ApJ 458, 621; [30] Ruiterkamp, R. et al. 2005 A&A 432, 515; [31] Ruiterkamp, R. et al. 2002 A&A 390, 1153; [32] Vuong, M. H. & Foing, B. H 2000 A&A 363, L5; [33] Le Page, V. et al 2001 ApJS 132, 233; [34] Ehrenfreund, P et al. 2007 P&SS 55, 383; [35] Bryson, K. L., Peeters, Z., Salama, F., Foing, B., Ehrenfreund, P. et al. 2011 AdSpR 48, 1980; [36] Mattioda, A., Cook, A., Ehrenfreund, P. et al. 2012 AsBio 12, 841.

  17. Sleep on the right side-Get cancer on the left?

    PubMed

    Hallberg, Orjan; Johansson, Olle

    2010-06-01

    Breast cancer frequently occurs in the left breast among both women and men [R. Roychoudhuri, V. Putcha, H. Møller, Cancer and laterality: a study of the five major paired organs (UK), Cancer Causes Control 17 (2006) 655-662; M.T. Goodman, K.H. Tung, L.R. Wilkens, Comparative epidemiology of breast cancer among men and women in the US, 1996 to 2000, Cancer Causes Control 17 (2006) 127-136; C.I. Perkins, J. Hotes, B.A. Kohler, H.L. Howe, Association between breast cancer laterality and tumor location, United States, 1994-1998, Cancer Causes Control 15 (2004) 637-645; H.A. Weiss, S.S. Devesa, L.A. Brinton, Laterality of breast cancer in the United States, Cancer Causes Control 7 (1996) 539-543; A. Ekbom, H.O. Adami, D. Trichopoulos, M. Lambe, C.C. Hsieh, J. Pontén, Epidemiologic correlates of breast cancer laterality (Sweden), Cancer Causes Control 5 (1994) 510-516]. Moreover, recent results showed that the left side of the body is more prone to melanoma than the right side [D.H. Brewster, M.J. Horner, S. Rowan, P. Jelfs, E. de Vries, E. Pukkala, Left-sided excess of invasive cutaneous melanoma in six countries, Eur. J. Cancer 43 (2007) 2634-2637]. Current explanations for left-sided breast cancer include handedness [L. Titus-Ernstoff, P.A. Newcomb, K.M. Egan, et al., Left-handedness in relation to breast cancer risk in postmenopausal women, Epidemiology 11 (2000) 181-184; M.A. Kramer, S. Albrecht, R.A. Miller, Handedness and the laterality of breast cancer in women, Nurs. Res. 34 (1985) 333-337; M.K. Ramadhani, S.G. Elias, P.A. van Noord, D.E. Grobbee, P.H. Peeters, C.S. Uiterwaal, Innate left handedness and risk of breast cancer: case-cohort study, BMJ 331 (2005) 882-883], size difference, nursing preference, and brain structure. However, men are affected even more by left laterality than women, thus many of these explanations are unconvincing. Increasing rates of skin melanoma have been associated with immune-disruptive radiation from FM/TV transmitters [O

  18. Land - Ocean Climate Linkages and the Human Evolution - New ICDP and IODP Drilling Initiatives in the East African Rift Valley and SW Indian Ocean

    NASA Astrophysics Data System (ADS)

    Zahn, R.; Feibel, C.; Co-Pis, Icdp/Iodp

    2009-04-01

    enable us to establish the linkages between the ocean climatology of the SW Indian and terrestrial climates of Eastern Africa during key periods of global climate change. Combining the ICDP records of East African terrestrial climate at key hominin sites with IODP records of marine climate variability at the SE African continental margin will help to test if pulses of hominin evolutionary innovation were linked with periods of enhanced variability of local terrestrial environments and marine climatology of the Indian Ocean. * co-PIs of the ICDP initiative HSPDP are A.S. Cohen, R. Arrowsmith, A.K. Behrensmeyer, C. Feibel, R. Johnson, Z. Kubsa, D. Olago, R. Potts, R. Renaut * co-PIs of the IODP initiative SAFARI are R. Zahn, I. Hall, R. Schneider, M. Á. Bárcena, S. Barker, A. Biastoch, Chr. Charles, J. Compton, R. Cowling, P. Diz, L. Dupont, J.-A. Flores, S. Goldstein, S. Hemming, K. Holmgren, J. Lee-Thorp, G. Knorr, C. Lear, A. Mazaud, G. Mortyn, F. Peeters, B. Preu, R. Rickaby, J. Rogers, A. Rosell-Mele, Chr. Reason, V. Spiess, M. Trauth, G. Uenzelmann-Neben, S. Weldeab, P. Ziveri

  19. COST Action MP0806 'Particles in Turbulence': International Conference on Fundamentals, Experiments, Numeric and Applications

    NASA Astrophysics Data System (ADS)

    Abel, Markus; Bodenschatz, Eberhard; Toschi, Federico

    2011-12-01

    also like to thank the students from Potsdam University for their exquisite help. We are very thankful to Anita Peeters for her unwavering support and help in the organization of this particular event, as well as, for the efforts ensuring the smooth running of the COST Action 'Particles in turbulence'. Markus Abel, Eberhard Bodenschatz, Federico Toschi The PDF files of the conference program and conference poster are attached.

  20. A new noble gas paleoclimate record in Texas — Basic assumptions revisited

    NASA Astrophysics Data System (ADS)

    Castro, Maria Clara; Hall, Chris Michael; Patriarche, Delphine; Goblet, Patrick; Ellis, Brian Robert

    2007-05-01

    A generally accepted basic principle in relation to the use of the noble gas thermometer in groundwater flow systems is that high-frequency noble gas climatic signals are lost due to the effect of dispersion. This loss of signal, combined with 14C dating issues, makes it only suited to identify major climatic events such as the Last Glacial Maximum (LGM). Consequently, the identification of significant noble gas temperature (NGT) cooling (≥ 5 °C) with respect to present time has systematically been associated with the occurrence of the LGM even when reasonable water age controls were unavailable. It has also become apparent at a number of studied sites that modern NGTs estimated through standard models [M. Stute, P. Schlosser, Principles and applications of the noble gas paleothermometer, in: P.K. Swart, K.C. Lohmann, J.A. McKenzie, S. Savin, (Eds), Climate change in continental isotopic records, Geophysical monograph 78, AGU (1993) 89-100.; W. Aeschbach-Hertig, F. Peeters, U. Beyerle, R. Kipfer, Paleotemperature reconstruction from noble gases in ground water taking into account equilibration with entrapped air, Nature 405(6790) (2000) 1040-1044.] are unable to reproduce ground temperatures at the interface with the unsaturated zone, a basic requirement for proper paleoclimate reconstruction through noble gases. Instead, a systematic bias to low NGTs in recharge areas is observed. The Carrizo aquifer, in which the LGM was previously identified [M. Stute, P. Schlosser, J.F. Clark, W.S. Broecker, Paleotemperatures in the Southwestern United States derived from noble gases in ground water, Science 256(5059) (1992) 1000-1001.] and which presents an NGT bias of over 4 °C, is an ideal setting to analyze and revise basic principles and assumptions in relation with the use of the noble gas thermometer. Here, we present a new noble gas data set (49 measurements) collected at 20 different locations in the Carrizo aquifer. This new data set together with previously

  1. PREFACE: XXXth International Colloquium on Group Theoretical Methods in Physics (ICGTMP) (Group30)

    NASA Astrophysics Data System (ADS)

    Brackx, Fred; De Schepper, Hennie; Van der Jeugt, Joris

    2015-04-01

    Christophe Peeters, Deputy Mayor of the City of Ghent, was followed by a reception in the historical "Pacificatiezaal" of the City Hall. On Wednesday afternoon the participants had the opportunity to take a guided tour through medieval Ghent, admiring its wide range of monuments. The tour was followed by a much-appreciated boat trip exploring the canals and rivers of Ghent, all in sunny weather. On Thursday evening the conference banquet was held in the "Brasserie HA". Located in the Handelsbeurs Ghent. In the majestic banquet hall, the participants were not only treated to an exclusive dinner, but also to some fine piano music by Dmitry Gal'tsov and Richard Kerner. The conference was sponsored by: American Institute of Physics (AIP Publishing), Clay Mathematics Institute, Clifford Research Group - Faculty of Engineering and Architecture (Ghent Unviversity), Elsevier, Faculty of Sciences (Ghent University), Fonds de la Recherche Scientifique (FNRS), Foundation Compositio Mathematica, FWO Research Foundation - Flanders, International Association of Mathematical Physics, International Solvay Institutes, International Union of Pure and Applied Physics, National Science Foundation (USA) and Springer Birkhäuser. We would like to thank all our sponsors for their generous support. It took more than two years to organise a conference of such a size and importance. We express our gratitude to the International Advisory Committee for its help in selecting the plenary speakers and to the external members of the Organising Committee for their helpful suggestions and advice. We thank Wouter Dewolf for his devoted secretarial, administrative and organisational work and Vera Vanden Driessche for arranging the "Accompanying persons' programme". Finally, a big 'thank you' to all the local people (administrative and technical staff, research assistants and research students) for their devoted and tireless work in preparing and running the conference. Fred Brackx, Hennie De Schepper and Joris

  2. Preface

    NASA Astrophysics Data System (ADS)

    Benage, J. F.; Dufty, J. W.; Murillo, M. S.

    2003-06-01

    , Israel N W Ashcroft Cornell University, USA J Bollinger NIST, Boulder, USA J-M Caillol Université Paris XI, France D M Ceperley University of Illinois, USA G Chabrier Ecole Normale Supérieure de Lyon, France J Clerouin CEA Bruyeres-le-Chatel, France S das Sarma University of Maryland, USA A DeSilva University of Maryland, USA H DeWitt Lawrence Livermore National Laboratory, USA D Dubin University of California, USA J Dufty University of Florida, USA W Ebeling Humboldt University, Germany V Filinov Institute of High Temperature Physics, Russia M Fisher University of Maryland, USA V E Fortov Institute of High Temperature Physics, Russia K Golden University of Vermont, USA J-P Hansen Cambridge University, UK F Hensel Philipps-Universität, Germany G Kalman Boston College, USA W Kohn University of California, USA H Lowen University of Dusseldorf, Germany G Morfill Max Planck Institute of Extraterrestrial Physics, Germany D Neilson University of New South Wales, Australia G Patey University of British Columbia, Canada F Peeters University of Antwerp, Germany D Pines Los Alamos National Laboratory, USA G Roepke University of Rostock, Germany M Rosenberg University of California, USA Y Rosenfeld Negev Nuclear Research Center, Israel M Schlanges University of Greifswald, Germany G Senatore University of Trieste, France H Totsuji Okayama University, Japan J Weisheit Los Alamos National Laboratory, USA Obituary Forty years of plasma line broadening---in memory of Professor Charles Hooper Jr Our friend and colleague, Charles Hooper Jr, died on 5 May 2002 after a long illness and a valiant battle against it. This presentation is a brief look back at the issues in plasma line broadening over the past forty years, and the contributions to them by Chuck and his students. Chuck graduated from Dartmouth College in 1954. He served in the US Navy for two years before receiving a PhD from Johns Hopkins University in 1963. He then joined the faculty at the University of Florida where his