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Sample records for arpo bibi steinberg

  1. Steinberg conformal algebras

    NASA Astrophysics Data System (ADS)

    Mikhalev, A. V.; Pinchuk, I. A.

    2005-06-01

    The structure of Steinberg conformal algebras is studied; these are analogues of Steinberg groups (algebras, superalgebras).A Steinberg conformal algebra is defined as an abstract algebra by a system of generators and relations between the generators. It is proved that a Steinberg conformal algebra is the universal central extension of the corresponding conformal Lie algebra; the kernel of this extension is calculated.

  2. 65th birthday Jack Steinberger

    ScienceCinema

    None

    2016-07-12

    Laudatio pour Jack Steinberger né le 25 mai 1921, à l'occasion de son 65me anniversaire et sa retraite officielle, pour sa précieuse collaboration au Cern. Néanmoins son principal activité continuera comme avant dans sa recherche au Cern. Plusieurs orateurs prennent la parole (p.ex. E.Picasso) pour le féliciter et lui rendre hommage

  3. 65th birthday Jack Steinberger

    SciTech Connect

    2007-12-04

    Laudatio pour Jack Steinberger né le 25 mai 1921, à l'occasion de son 65me anniversaire et sa retraite officielle, pour sa précieuse collaboration au Cern. Néanmoins son principal activité continuera comme avant dans sa recherche au Cern. Plusieurs orateurs prennent la parole (p.ex. E.Picasso) pour le féliciter et lui rendre hommage

  4. Parents as Partners for Preparing Deaf Students for Bi-Bi Educational Programs.

    ERIC Educational Resources Information Center

    LaSasso, Carol J.; Metzger, Melanie A.

    This paper describes Bilingual-Bicultural (BiBi) instructional programs for students with hearing impairments and proposes a model for BiBi instruction which uses parents as partners with instructors to develop the linguistic abilities of hearing-impaired students. In the model, traditionally spoken languages are conveyed via cued speech instead…

  5. Parents as Partners for Preparing Deaf Students for Bi-Bi Educational Programs.

    ERIC Educational Resources Information Center

    LaSasso, Carol J.; Metzger, Melanie A.

    This paper describes Bilingual-Bicultural (BiBi) instructional programs for students with hearing impairments and proposes a model for BiBi instruction which uses parents as partners with instructors to develop the linguistic abilities of hearing-impaired students. In the model, traditionally spoken languages are conveyed via cued speech instead…

  6. The Media Do Matter: Comment on Steinberg and Monahan (2011)

    ERIC Educational Resources Information Center

    Brown, Jane D.

    2011-01-01

    Steinberg and Monahan's (2011) reanalysis of the Teen Media longitudinal survey of adolescents does not meet prevailing standards for propensity score analysis and therefore does not undermine the original conclusions of the Brown, L'Engle, Pardun, Guo, Kenneavy, and Jackson (2006) analysis. The media do matter in the sexual socialization of…

  7. The Media Do Matter: Comment on Steinberg and Monahan (2011)

    ERIC Educational Resources Information Center

    Brown, Jane D.

    2011-01-01

    Steinberg and Monahan's (2011) reanalysis of the Teen Media longitudinal survey of adolescents does not meet prevailing standards for propensity score analysis and therefore does not undermine the original conclusions of the Brown, L'Engle, Pardun, Guo, Kenneavy, and Jackson (2006) analysis. The media do matter in the sexual socialization of…

  8. The media do matter: comment on Steinberg and Monahan (2011).

    PubMed

    Brown, Jane D

    2011-03-01

    Steinberg and Monahan's (2011) reanalysis of the Teen Media longitudinal survey of adolescents does not meet prevailing standards for propensity score analysis and therefore does not undermine the original conclusions of the Brown, L'Engle, Pardun, Guo, Kenneavy, and Jackson (2006) analysis. The media do matter in the sexual socialization of adolescents. PsycINFO Database Record (c) 2011 APA, all rights reserved.

  9. The stability and the electronic structure of ultrathin Bi/Bi2Se3 heterostructure

    NASA Astrophysics Data System (ADS)

    Liu, X.; Du, X.; Huang, G. Q.

    2016-12-01

    The stability and the electronic structure of ultrathin Bi/Bi2Se3 heterostructure are studied from density-functional theory by including spin-orbit coupling. Our calculations show that the thinnest and dynamically stable heterostructure is one bilayer Bi deposited on Bi2Se3 with the thickness of two quintuple layers. Due to charge transfer and the strong hybridize effect at the interface, the band structure of ultrathin heterostructure make a large change, but the Dirac-like surface states persist. Our findings propose the possibility to engineer heterostructure to obtain ultrathin topological materials.

  10. Narrow Assessments Misrepresent Development and Misguide Policy: Comment on Steinberg, Cauffman, Woolard, Graham, and Banich (2009)

    ERIC Educational Resources Information Center

    Fischer, Kurt W.; Stein, Zachary; Heikkinen, Katie

    2009-01-01

    Intellectual and psychosocial functioning develop along complex learning pathways. Steinberg, Cauffman, Woolard, Graham, and Banich measured these two classes of abilities with narrow, biased assessments that captured only a segment of each pathway and created misleading age patterns based on ceiling and floor effects. It is a simple matter to…

  11. Award for Distinguished Contributions to Research in Public Policy: Laurence Steinberg

    ERIC Educational Resources Information Center

    American Psychologist, 2009

    2009-01-01

    Laurence Steinberg, recipient of the Award for Distinguished Contributions to Research in Public Policy, is cited for his extraordinary impact on policy in juvenile justice and child labor and on research into the role of parent and peer relationships in the development of children and adolescents. His groundbreaking research is marked by a…

  12. Award for Distinguished Contributions to Research in Public Policy: Laurence Steinberg

    ERIC Educational Resources Information Center

    American Psychologist, 2009

    2009-01-01

    Laurence Steinberg, recipient of the Award for Distinguished Contributions to Research in Public Policy, is cited for his extraordinary impact on policy in juvenile justice and child labor and on research into the role of parent and peer relationships in the development of children and adolescents. His groundbreaking research is marked by a…

  13. Narrow Assessments Misrepresent Development and Misguide Policy: Comment on Steinberg, Cauffman, Woolard, Graham, and Banich (2009)

    ERIC Educational Resources Information Center

    Fischer, Kurt W.; Stein, Zachary; Heikkinen, Katie

    2009-01-01

    Intellectual and psychosocial functioning develop along complex learning pathways. Steinberg, Cauffman, Woolard, Graham, and Banich measured these two classes of abilities with narrow, biased assessments that captured only a segment of each pathway and created misleading age patterns based on ceiling and floor effects. It is a simple matter to…

  14. Propensity scoring and the relationship between sexual media and adolescent sexual behavior: comment on Steinberg and Monahan (2011).

    PubMed

    Collins, Rebecca L; Martino, Steven C; Elliott, Marc N

    2011-03-01

    Longitudinal research has demonstrated a link between exposure to sexual content in media and subsequent changes in adolescent sexual behavior, including initiation of intercourse and various noncoital sexual activities. Based on a reanalysis of one of the data sets involved, Steinberg and Monahan (2011) have challenged these findings. However, propensity score approaches-especially the version of this method used by Steinberg and Monahan, which lacks covariates-do not necessarily result in more accurate estimates of treatment effects than does the regression with covariates approach employed by prior research. There are also a number of problems with the specific set of analyses presented by Steinberg and Monahan and the conclusion they draw from them. In contrast to Steinberg and Monahan's claim, there is substantial evidence of an association between sexual media exposure and adolescent sexual initiation.

  15. Propensity Scoring and the Relationship between Sexual Media and Adolescent Sexual Behavior: Comment on Steinberg and Monahan (2011)

    ERIC Educational Resources Information Center

    Collins, Rebecca L.; Martino, Steven C.; Elliott, Marc N.

    2011-01-01

    Longitudinal research has demonstrated a link between exposure to sexual content in media and subsequent changes in adolescent sexual behavior, including initiation of intercourse and various noncoital sexual activities. Based on a reanalysis of one of the data sets involved, Steinberg and Monahan (2011) have challenged these findings. However,…

  16. Propensity Scoring and the Relationship between Sexual Media and Adolescent Sexual Behavior: Comment on Steinberg and Monahan (2011)

    ERIC Educational Resources Information Center

    Collins, Rebecca L.; Martino, Steven C.; Elliott, Marc N.

    2011-01-01

    Longitudinal research has demonstrated a link between exposure to sexual content in media and subsequent changes in adolescent sexual behavior, including initiation of intercourse and various noncoital sexual activities. Based on a reanalysis of one of the data sets involved, Steinberg and Monahan (2011) have challenged these findings. However,…

  17. U-Pb geochronology and geochemistry of Bibi-Maryam pluton, eastern Iran: Implication for the late stage of the tectonic evolution of the Sistan Ocean

    NASA Astrophysics Data System (ADS)

    Delavari, Morteza; Amini, Sadraddin; Schmitt, Axel K.; McKeegan, Kevin D.; Mark Harrison, T.

    2014-07-01

    The Bibi-Maryam pluton crops out in the Sistan suture zone, eastern Iran. This pluton is a 1.5 × 2 km stock composed of leucocratic tonalite, granodiorite and granite. U-Pb zircon geochronology of a leucogranite indicates an emplacement age of 58.6 ± 2.1 Ma (95% confidence). The Bibi-Maryam rock suite is sodic with elevated Na2O/K2O (2.9 to 5.5), Sr/Y (15.6-62.2), La/Yb (13.3-22.2), and low MgO (0.86-1.81) abundances. It lacks significant Eu anomalies. Because of these geochemical characteristics, Bibi-Maryam rocks are similar to high-SiO2 adakites. Trace element modeling indicates that the Bibi-Maryam adakitic rocks could be produced by 5-8% non-modal batch partial melting from a source with composition of 95% N-MORB + 5% sediment in the presence of 35-40% amphibole + 5-10% garnet + 55-60% clinopyroxene + 1% apatite + 1% rutile. This source mineralogy is similar to hornblende eclogite or garnet amphibolites. Collectively, these data provide new constraints for the evolution of the Sistan suture zone and suggest that the Bibi-Maryam pluton formed via slab melting in an oceanic arc and pre-plate collision tectonic setting. This implies that the closure of the Sistan Ocean and Lut-Afghan continental blocks collision happened after the Bibi-Maryam emplacement at 58.6 ± 2.1 Ma.

  18. Applying Steinberg's model to the Hugoniot elastic limit of porous boron carbide specimens

    SciTech Connect

    Brar, N.S.; Rosenberg, Z.; Bless, S.J. )

    1991-06-01

    Plate-impact experiments were performed on boron carbide specimens, having different porosities, in order to measure their Hugoniot elastic limit (HEL) values. The measurements were performed with commercial manganin gauges embedded at the back surface of the specimen and backed by a thick Plexiglas disk. The measured values show an almost linear decrease in the HEL values between 194 kbar (For the fully dense material) to 96 kbar for a specimen with 16.3% porosity. These values were compared with a theoretical model (suggested by D. Steinberg (LLL report LLL-UCID-16946, 1975)) which accounts for the dependence of the HEL on porosity, and the agreement is shown to be good.

  19. Size-controllable synthesis of Bi/Bi2O3 heterojunction nanoparticles using pulsed Nd:YAG laser deposition and metal-semiconductor-heterojunction-assisted photoluminescence

    NASA Astrophysics Data System (ADS)

    Patil, Ranjit A.; Wei, Mao-Kuo; Yeh, P.-H.; Liang, Jyun-Bo; Gao, Wan-Ting; Lin, Jin-Han; Liou, Yung; Ma, Yuan-Ron

    2016-02-01

    We synthesized Bi/Bi2O3 heterojunction nanoparticles at various substrate temperatures using the pulsed laser deposition (PLD) technique with a pulsed Nd:YAG laser. The Bi/Bi2O3 heterojunction nanoparticles consisted of Bi nanoparticles and Bi2O3 surface layers. The average diameter of the Bi nanoparticles and the thickness of the Bi2O3 surface layer are linearly proportional to the substrate temperature. The heterojunctions between the Bi nanoparticles and Bi2O3 surface layers, which are the metal-semiconductor heterojunctions, can strongly enhance the photoluminescence (PL) of the Bi/Bi2O3 nanoparticles, because the metallic Bi nanoparticles can provide massive free Fermi-level electrons for the electron transitions in the Bi2O3 surface layers. The enhancement of PL emission at room temperature by metal-semiconductor-heterojunctions make the Bi/Bi2O3 heterojunction nanoparticles potential candidates for use in optoelectronic nanodevices, such as light-emitting diodes (LEDs) and laser diodes (LDs).We synthesized Bi/Bi2O3 heterojunction nanoparticles at various substrate temperatures using the pulsed laser deposition (PLD) technique with a pulsed Nd:YAG laser. The Bi/Bi2O3 heterojunction nanoparticles consisted of Bi nanoparticles and Bi2O3 surface layers. The average diameter of the Bi nanoparticles and the thickness of the Bi2O3 surface layer are linearly proportional to the substrate temperature. The heterojunctions between the Bi nanoparticles and Bi2O3 surface layers, which are the metal-semiconductor heterojunctions, can strongly enhance the photoluminescence (PL) of the Bi/Bi2O3 nanoparticles, because the metallic Bi nanoparticles can provide massive free Fermi-level electrons for the electron transitions in the Bi2O3 surface layers. The enhancement of PL emission at room temperature by metal-semiconductor-heterojunctions make the Bi/Bi2O3 heterojunction nanoparticles potential candidates for use in optoelectronic nanodevices, such as light-emitting diodes

  20. Low Emissions Alternative Power (LEAP) Project Office Business Team of the Aeropropulsion Research Program Office (ARPO) Org. 0140

    NASA Technical Reports Server (NTRS)

    Buttler, Jennifer A.

    2004-01-01

    The program for which I am working at this summer is Propulsion and Power/Low Emissions Alternative Power (P&P/LEAP). It invests in a fundamental TRL 1-6 research and technology portfolio that will enable the future of: Alternative fuels and/or alternative propulsion systems, non-combustion (electric) propulsion systems. P&P/LEAP will identify and capitalize on the highest potential concepts generated both internal and external to the Agency. During my 2004 summer at NASA Glenn Research Center, I worked with my mentor Barbara Mader, in the Project Office with the Business Team completing various tasks for the project and personnel. The LEAP project is a highly matrixed organization. The Project Office is responsible for the goals advocacy and dollar (budget) of the LEAP project. The objectives of the LEAP Project are to discover new energy sources and develop unconventional engines and power systems directed towards greatly reduced emissions, enable new vehicle concepts for public mobility, new science missions and national security. The Propulsion and PowerLow Emissions Alternative Power directly supports the environmental, mobility, national security objectives of the Vehicle Systems Program and the Aeronautics Technology Theme. Technology deliverables include the demonstration through integrated ground tests, a constant volume combustor in an engine system, and UAV/small transport aircraft all electric power system. My mentor serves as a key member of the management team for the Aeropropulsion Research Program Office (ARPO). She has represented the office on numerous occasions, and is a member of a number of center-wide panels/teams, such as the Space management Committee and is chair to the Business Process Consolidation Team. She is responsible for the overall coordination of resources for the Propulsion and Power Project - from advocacy to implementation. The goal for my summer at NASA was to document processes and archive program documents from the past

  1. Low Emissions Alternative Power (LEAP) Project Office Business Team of the Aeropropulsion Research Program Office (ARPO) Org. 0140

    NASA Technical Reports Server (NTRS)

    Buttler, Jennifer A.

    2004-01-01

    The program for which I am working at this summer is Propulsion and Power/Low Emissions Alternative Power (P&P/LEAP). It invests in a fundamental TRL 1-6 research and technology portfolio that will enable the future of: Alternative fuels and/or alternative propulsion systems, non-combustion (electric) propulsion systems. P&P/LEAP will identify and capitalize on the highest potential concepts generated both internal and external to the Agency. During my 2004 summer at NASA Glenn Research Center, I worked with my mentor Barbara Mader, in the Project Office with the Business Team completing various tasks for the project and personnel. The LEAP project is a highly matrixed organization. The Project Office is responsible for the goals advocacy and dollar (budget) of the LEAP project. The objectives of the LEAP Project are to discover new energy sources and develop unconventional engines and power systems directed towards greatly reduced emissions, enable new vehicle concepts for public mobility, new science missions and national security. The Propulsion and PowerLow Emissions Alternative Power directly supports the environmental, mobility, national security objectives of the Vehicle Systems Program and the Aeronautics Technology Theme. Technology deliverables include the demonstration through integrated ground tests, a constant volume combustor in an engine system, and UAV/small transport aircraft all electric power system. My mentor serves as a key member of the management team for the Aeropropulsion Research Program Office (ARPO). She has represented the office on numerous occasions, and is a member of a number of center-wide panels/teams, such as the Space management Committee and is chair to the Business Process Consolidation Team. She is responsible for the overall coordination of resources for the Propulsion and Power Project - from advocacy to implementation. The goal for my summer at NASA was to document processes and archive program documents from the past

  2. Size-controllable synthesis of Bi/Bi2O3 heterojunction nanoparticles using pulsed Nd:YAG laser deposition and metal-semiconductor-heterojunction-assisted photoluminescence.

    PubMed

    Patil, Ranjit A; Wei, Mao-Kuo; Yeh, P-H; Liang, Jyun-Bo; Gao, Wan-Ting; Lin, Jin-Han; Liou, Yung; Ma, Yuan-Ron

    2016-02-14

    We synthesized Bi/Bi2O3 heterojunction nanoparticles at various substrate temperatures using the pulsed laser deposition (PLD) technique with a pulsed Nd:YAG laser. The Bi/Bi2O3 heterojunction nanoparticles consisted of Bi nanoparticles and Bi2O3 surface layers. The average diameter of the Bi nanoparticles and the thickness of the Bi2O3 surface layer are linearly proportional to the substrate temperature. The heterojunctions between the Bi nanoparticles and Bi2O3 surface layers, which are the metal-semiconductor heterojunctions, can strongly enhance the photoluminescence (PL) of the Bi/Bi2O3 nanoparticles, because the metallic Bi nanoparticles can provide massive free Fermi-level electrons for the electron transitions in the Bi2O3 surface layers. The enhancement of PL emission at room temperature by metal-semiconductor-heterojunctions make the Bi/Bi2O3 heterojunction nanoparticles potential candidates for use in optoelectronic nanodevices, such as light-emitting diodes (LEDs) and laser diodes (LDs).

  3. Kinetics of Spanish broom peroxidase obeys a Ping-Pong Bi-Bi mechanism with competitive inhibition by substrates.

    PubMed

    Pérez Galende, Patricia; Hidalgo Cuadrado, Nazaret; Kostetsky, Eduard Ya; Roig, Manuel G; Villar, Enrique; Shnyrov, Valery L; Kennedy, John F

    2015-11-01

    In plants, adverse conditions often induce an increase in reactive oxygen species (ROS) such as hydrogen peroxide (H2O2). H2O2 is reduced to water, and thus becomes detoxified by enzymes such as Cytisus multiflorus peroxidase (CMP). Here, the steady-state kinetics of the H2O2-supported oxidation of different organic substrates by CMP was investigated. Analysis of the initial rates vs. H2O2 and reducing substrate concentrations proved to be consistent with a substrate-inhibited Ping-Pong Bi-Bi reaction mechanism. The phenomenological approach expresses the peroxidase Ping-Pong mechanism in the form of the Michaelis-Menten equation and affords an interpretation of the effects in terms of the kinetic parameters [Formula: see text] , [Formula: see text] , kcat, [Formula: see text] , [Formula: see text] and of the microscopic rate constants, k1 and k3, of the shared three-step catalytic cycle of peroxidases.

  4. [The terminal patient: Jewish religious law, the Steinberg report and the bioethical discourse in Israel].

    PubMed

    Barilan, Y Michael

    2003-07-01

    This article surveys key texts in contemporary orthodox Jewish law (Halakha) with regard to end-of-life decision making. The author proposes twelve principles that govern Jewish law in that matter. The article proceeds to examine the Steinberg report in the light of Halakha. Orthodox Judaism regards human life as a prime value, which is always beyond consideration of economical means or quality of life. The avoidance of suffering is the only justification to shorten the life of the sufferer, provided that the acts performed do not fall within the Halakhic definition of murder, namely active and direct action that shortens life. It is argued that the main challenge of bioethics in Israel is the bridging between the positive law of Halakha whose fundamental value is submission to God's will as manifested in Halakha, and the rationalism, universalism, and egalitarianism which constitute naturalistic ethics. This challenge may produce ideas such as the "clock machine". It is too early to know if this is a trickery, or genuine ethical creativity.

  5. In-Situ Hydrothermal Synthesis of Bi-Bi2O2CO3 Heterojunction Photocatalyst with Enhanced Visible Light Photocatalytic Activity

    NASA Astrophysics Data System (ADS)

    Kar, Prasenjit; Maji, Tuhin Kumar; Nandi, Ramesh; Lemmens, Peter; Pal, Samir Kumar

    2017-04-01

    Bismuth containing nanomaterials recently received increasing attention with respect to environmental applications because of their low cost, high stability and nontoxicity. In this work, Bi-Bi2O2CO3 heterojunctions were fabricated by in-situ decoration of Bi nanoparticles on Bi2O2CO3 nanosheets via a simple hydrothermal synthesis approach. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) were used to confirm the morphology of the nanosheet-like heterostructure of the Bi-Bi2O2CO3 composite. Detailed ultrafast electronic spectroscopy reveals that the in-situ decoration of Bi nanoparticles on Bi2O2CO3 nanosheets exhibit a dramatically enhanced electron-hole pair separation rate, which results in an extraordinarily high photocatalytic activity for the degradation of a model organic dye, methylene blue (MB) under visible light illumination. Cycling experiments revealed a good photochemical stability of the Bi-Bi2O2CO3 heterojunction under repeated irradiation. Photocurrent measurements further indicated that the heterojunction incredibly enhanced the charge generation and suppressed the charge recombination of photogenerated electron-hole pairs.

  6. Reconstruction of the Unified Soviet National Economic Balance Tables, 1970 - 1983: A Replication and Evaluation of Steinberg’s Reconstruction Methodology. Volume 1: Technical

    DTIC Science & Technology

    1987-10-09

    I ct(•~ ~r , frilormation era~n ad• l:i••.tr ~I ’i" 1111 11111lilt 11 e h Utice at Management g , aperw 4 1 8 8 ) 1 AGENCY USE ONLY (Leave blank) 2...DSA version and the original Steinberg version of the reconstruction are based on the same fundamental methodology, the resulting tables are not...Balance) (3) FINANCIAL WT061 Distribution of State Profit WT071 Capital Invesment in Current Prices WT049* Unified Balance of Household Income and

  7. Simulation and Interpretation of the BIBI Ratio CB (.), as a Function of Thermal Parameters of the Low Inertia Polyethylene Wall of Greenhouses

    NASA Astrophysics Data System (ADS)

    Bendimerad, S.; Mahdjoub, T.; Bibi-Triki, N.; Bessenouci, M. Z.; Draoui, B.; Bechar, H.

    The conventional agricultural tunnel greenhouse is highly widespread in Mediterranean countries, despite the shortcomings it presents, specifically the overheating during the day and the intense cooling at night. This can sometimes lead to an internal thermal inversion. The chapel-shaped glass greenhouse is relatively more efficient, but its evolution remains slow because of its investment cost and amortization. The thermal behavior of a greenhouse has often been studied, mainly during the night. In order to contribute to a better climatic management of the greenhouse, we proposed to develop a thermal analysis model. In this work, a ratio called BIBI was developed to characterize the covering material. This thermal evolution state depends on the degree of air-tightness of this covering material and its physical characteristics. It has to be transparent to solar rays, and must as well absorb and reflect infrared rays emitted by the soil. This leads to trapped solar rays, called the "greenhouse effect". In this paper we propose the modeling and analysis of the thermal behavior of the polyethylene (PE) wall of the experimental tunnel greenhouse.

  8. Late Cretaceous evolution of the northern Sistan suture zone, eastern Iran: Implications of magnetic fabrics and microstructures in the Bibi Maryam granitoid

    NASA Astrophysics Data System (ADS)

    Etemadkhah, Zeinab; Khatib, Mohammad Mahdi; Zarrinkoub, Mohammad Hossein

    2015-04-01

    Anisotropy of magnetic susceptibility (AMS) survey supported by field and microstructural studies have been applied on the Late Cretaceous Bibi Maryam granitoid (BMG) in the northern Sistan suture zone (SSZ), east of Iran. The BMG is composed of quartzdiorite-tonalite with late granodiorite dykes and stocks that are surrounded by steeply SW-dipping Neh shear zone (NSZ). The magmatic fabrics are characterized by transpressional environment dominated by steep dipping foliations (mean strike: N13°W) and sub-horizontal stretching lineations (mean trend: 167°). Based on microstructural studies, it is inferred that these fabrics are related to emplacement and cooling of the pluton and the internal fabrics revealed are evidence of a deformation continuum in the granitoid from magmatic to solid state. Deformation in the region continued even after the BMG had fully crystallized, which led to development of the NW-SE foliations and lineation trend that these fabrics are subparallel with the NSZ. The BMG has emplaced in a transpressional setting that was controlled by a NW-SE stretching direction and supported the model that has proposed the relationship between granitoid emplacement and oblique intra-oceanic subduction of the Neotethys during the Late Cretaceous already recognized in this part of the SSZ.

  9. Changing the Context Is Important and Necessary, but Not Sufficient, for Reducing Adolescent Risky Sexual Behavior: A Reply to Steinberg (2015).

    PubMed

    Bryan, Angela D; Gillman, Arielle S; Hansen, Natasha S

    2016-07-01

    Starting school later, keeping adolescents busy with structured programming, and making free condoms available, as Steinberg (2015) suggests, are important and necessary steps, but they are simply not sufficient if the goal is reducing sexually transmitted infections and unplanned pregnancy. We agree that the current state of affairs, which in many schools involves sexuality education using programs that are not empirically supported, is unacceptable. However, abandoning sexuality education entirely would leave adolescents ill equipped to protect themselves. Despite the fact that current intervention technology is neither perfect nor optimally effective, there are empirically supported, school-based sexual risk reduction interventions that teach these skills and are readily available. In addition, even though we agree that structured afternoon programs for school-aged adolescents would reduce the opportunity for sexual risk behavior during the school years, such programs would not address the demographic reality of sexual risk that continues for adolescents and emerging adults far past the end of traditional secondary education. We believe Steinberg's suggestions are an excellent start and ought to be implemented. But complementary to this approach should be the use of existing empirically supported sexual risk reduction interventions and research into the development of even more effective interventions. © The Author(s) 2016.

  10. Achieving Bidirectional Long Delays In Pulmonary Vein Antral Lines Prior To Bidirectional Block In Patients With Paroxysmal Atrial Fibrillation (The Bi-Bi Technique For Atrial Fibrillation Ablation).

    PubMed

    Mina Md Facc Fhrs, Adel F; L Warnecke Pa-C, Nicholas

    2016-01-01

    Background: Pulmonary Vein Antral isolation (PVAI) is currently the standard of care for both paroxysmal and persistent atrial fibrillation ablation. Reconnection to the pulmonary vein is the most common cause of recurrence of atrial fibrillation. Achieving the endpoint of bidirectional block (BDB) for cavotricuspid isthmus dependant flutter has improved our outcomes for atrial flutter ablation. With this we tried to achieve long delays in the pulmonary veins antral lines prior to complete isolation comparable to those delays found in patient with bidirectional block of atrial flutter lines. Study Objective:The objective of this paper was to evaluate feasibility and efficacy of achieving Bidirectional long delays in pulmonary vein antral lines prior to Bidirectional Block in patient with paroxysmal atrial fibrillation. Method: A retrospective analysis was performed on patients who had paroxysmal atrial fibrillation procedures at Unity Point Methodist from January 2015 to January 2016. 20 consecutive patients with paroxysmal atrial fibrillation who had AF ablation using the Bi-Bi technique were evaluated. Result: Mean age was 63, number of antiarrhythmic used prior to ablation was 1.4, mean left atrial size was 38 mm. Mean chads score was 1.3. Mean EF was 53%. Long delays in the left antral circumferential lines were achieved with mean delay of 142 milliseconds +/-100. Also long delays in the right antral circumferential lines were achieved with mean delay of 150 milliseconds +/-80. 95 % (19/20) of patients were free of any atrial arrhythmias and were off antiarrhythmic medications for AF post procedure. There was only one transient complication in one patient who developed a moderate pericardial effusion that was successfully drained with no hemodynamic changes. The only patient who had recurrence was found to have asymptomatic AF with burden on his device <1%, this patient was also found to have non PV triggers for his AF. In patients with only PV triggered AF

  11. Bi-Bi to MCE?

    ERIC Educational Resources Information Center

    Stewart, David A.

    1993-01-01

    This paper discusses the role of American Sign Language (ASL) in educating deaf children, based on the history of using manually coded English (MCE). The paper concludes that use of ASL should not be the ultimate goal of bilingual bicultural programs, and, in some classrooms, the optimal program will be complementary use of ASL and MCE. (JDD)

  12. Steinberg ``AUDIOMAPS'' Music Appreciation-Via-Understanding: Special-Relativity + Expectations ``Quantum-Theory'': a Quantum-ACOUSTO/MUSICO-Dynamics (QA/MD)

    NASA Astrophysics Data System (ADS)

    Fender, Lee; Steinberg, Russell; Siegel, Edward Carl-Ludwig

    2011-03-01

    Steinberg wildly popular "AUDIOMAPS" music enjoyment/appreciation-via-understanding methodology, versus art, music-dynamics evolves, telling a story in (3+1)-dimensions: trails, frames, timbres, + dynamics amplitude vs. music-score time-series (formal-inverse power-spectrum) surprisingly closely parallels (3+1)-dimensional Einstein(1905) special-relativity "+" (with its enjoyment-expectations) a manifestation of quantum-theory expectation-values, together a music quantum-ACOUSTO/MUSICO-dynamics(QA/MD). Analysis via Derrida deconstruction enabled Siegel-Baez "Category-Semantics" "FUZZYICS"="CATEGORYICS ('TRIZ") Aristotle SoO DEduction , irrespective of Boon-Klimontovich vs. Voss-Clark[PRL(77)] music power-spectrum analysis sampling-time/duration controversy: part versus whole, shows QA/MD reigns supreme as THE music appreciation-via-analysis tool for the listener in musicology!!! Connection to Deutsch-Hartmann-Levitin[This is Your Brain on Music, (06)] brain/mind-barrier brain/mind-music connection is subtle/compelling/immediate!!!

  13. "Kids R Bi-Bi": Sign Talk Development Project.

    ERIC Educational Resources Information Center

    Evans, Charlotte; Zimmer, Kyra

    Sign Talk Development Project (STDP) is a four-pronged project that grows out of needs identified through the program of Sign Talk Children's Centre (STCC). STCC is a bilingual/bicultural day care for children of deaf parents in Winnipeg, Manitoba. The center offers programming in two languages, American Sign Language (ASL) and English; and in two…

  14. Synthesis and Biological Activity of Manganese (II) Complexes of Phthalic and Isophthalic Acid: X-Ray Crystal Structures of [Mn(ph)(Phen)2(H2O)]· 4H2O, [Mn(Phen)2(H2O)2]2(Isoph)2(Phen)· 12H2O and {[Mn(Isoph)(bipy)]4· 2.75biby}n(phH2 = Phthalic Acid; isoph = Isophthalic Acid; phen = 1,10-Phenanthroline; bipy = 2,2-Bipyridine)

    PubMed Central

    McCann, Malachy; Leon, Vanessa; Geraghty, Majella; McKee, Vickie; Wikaira, Jan

    2000-01-01

    Manganese(II) acetate reacts with phthalic acid (phH2) to give [Mn(ph)]·0.5H2O (1). Reaction of 1 with 1,10-phenanthroline produces [Mn(ph)(phen)]·2H2O (2) and [Mn(ph)(phen)2(H2O)]·4H2O (3). Reaction of isophthalic acid (isophH2) with manganese(II) acetate results in the formation of [Mn(isoph)]·2H2O (4). The addition of the N,N-donor ligands 1,10-phenanthroline or 2,2'-bipyridine to 4 leads to the formation of [Mn2 (isoph)2(phen)3)]·4H2O (5), [(Mn(phen)2(H2O)2]2(isoph)2(phen)·12H2O (6) and {[Mn(isoph)(bipy)]4·2.75 biby}n (7), respectively. Molecular structures of 3, 6 and 7 were determined crystallographically. In 3 the phthalate ligand is bound to the manganese via just one of its carboxylate groups in a monodentate mode with the remaining coordination sites filled by four phenanthroline nitrogen and one water oxygen atoms. In 6 the isophthalates are uncoordinated with the octahedral manganese center ligated by two phenanthrolines and two waters. In 7 the Isophthalate ligands act as bridges resulting in a polymeric structure. One of the carboxylate groups is chelating a single manganese with the other binding two metal centres in a bridging bidentate mode. The phthalate and isophthalate complexes, the metal free ligands and a number of simple manganes salts were each tested for their ability, to inhibit the growth of Candida albicans. Only the “metal free” 1,10-phenanthroline and its manganese complexes were found to be active. PMID:18475957

  15. Authors' Rejoinder to Respondents (Shulman, Steinberg, & Piquero, 2013)

    ERIC Educational Resources Information Center

    Males, Mike A.; Brown, Elizabeth A.

    2014-01-01

    Respondents, in "A Mistaken Account of the Age-Crime Curve: Response to Males and Brown," dispute our finding that virtually all of the discrepancy in violent crime rates between adolescents/emerging adults versus older adults is explained not by young age per se but by higher poverty levels among the young. Our rejoinder argues that…

  16. Jack Steinberger: Memories of the PS and of LEP

    NASA Astrophysics Data System (ADS)

    Tsesmelis, Emmanuel

    2012-03-01

    This contribution, a personal recollection by the author, is part of a special issue - CERN's accelerators, experiments and international integration 1959-2009. Guest Editor: Herwig Schopper [Schopper, Herwig. 2011. Editorial. Eur. Phys. J. H 36: 437

  17. Will the Courts Go Bi-Bi? IDEA 1997, the Courts, and Deaf Education.

    ERIC Educational Resources Information Center

    Pittman, Paula; Huefner, Dixie Snow

    2001-01-01

    This article reviews past litigation concerning the education of children with hearing impairments and explores new provisions under the Individuals with Disabilities Education Act as they affect communication issues. It is argued that new regulations may improve the position of parents who have adapted a bilingual-bicultural approach for their…

  18. Will the Courts Go Bi-Bi? IDEA 1997, the Courts, and Deaf Education.

    ERIC Educational Resources Information Center

    Pittman, Paula; Huefner, Dixie Snow

    2001-01-01

    This article reviews past litigation concerning the education of children with hearing impairments and explores new provisions under the Individuals with Disabilities Education Act as they affect communication issues. It is argued that new regulations may improve the position of parents who have adapted a bilingual-bicultural approach for their…

  19. Deaf Education Public School Teachers: What Are They Saying about Bi-Bi Philosophy?.

    ERIC Educational Resources Information Center

    Hadadian, Azar; Studnicky, Joan; Merbler, John

    1997-01-01

    A statewide survey of 64 public school teachers of deaf students found that, consistent with earlier research, teachers had inadequate knowledge of American Sign Language (ASL) and the role that the deaf community plays in the education of deaf children. Recommendations for preservice/inservice teacher training in ASL and current issues, such as…

  20. Implementation of joint health indicators in Europe - Joint Action for ECHIM. Arpo Aromaa on behalf of the ECHIM core group

    PubMed Central

    2012-01-01

    The story of the implementation of the joint EU health indicators (ECHI indicators) began in the 1990s after the Amsterdam Treaty. The first concrete step in establishing a health monitoring capacity for EU was the Commission working group set up in 1997. Several consecutive and parallel projects, notably the health indicator projects ECHI-1 and ECHI-2 between the years 2000 and 2005 led to a preparedness to implement the jointly agreed health indicators (ECHI shortlist) in all European countries. ECHIM (2005 – 2008) and the Joint Action for ECHIM (2009 - ) laid the foundation for the implementation of health indicators, and initiated Europe wide implementation proper. After the European recession of 2008 the circumstances in different countries were not optimal. Also the collaboration with the Commission could have been better. Nevertheless, the implementation process of the ECHI indicators is now well underway in most countries. By June 2012 half of the Member States had incorporated the ECHI indicators into their national health information system, and, if work can continue, by 2014 most countries are likely to have done so. Unfortunately, a gap may occur between the current programme and the next public health programme. The current momentum must not be lost. Therefore, all those responsible need to urge that the Commission (DG SANCO) together with the Member States helps to bridge the gap from June 2012 to January 2014. The new Public Health Programme provides the necessary financial instruments for setting up a permanent EU health information and reporting system. PMID:23043717

  1. Assembly of tetra, di and mononuclear molecular cadmium phosphonates using 2,4,6-triisopropylphenylphosponic acid and ancillary ligands.

    PubMed

    Chandrasekhar, Vadapalli; Sasikumar, Palani; Boomishankar, Ramamoorthy

    2008-10-14

    The reaction of ArPO(3)H(2) (Ar = 2,4,6-iPr(3)-C(6)H(2)) with Cd(CH(3)COO)(2).2H(2)O using various co-ligands such as methanol, dimethylformamide (DMF) and 3,5-dimethylpyrazole (DMPZH) resulted in the formation of tetranuclear assemblies [Cd(4)(ArPO(3))(2)(ArPO(3)H)(4)(CH(3)OH)(4)].3(CH(3)OH) (1), [Cd(4)(ArPO(3))(2)(ArPO(3)H)(4)(DMF)(4)].3(DMF) (2) and [Cd(4)(ArPO(3))(2)(ArPO(3)H)(4)(DMF)(2)(DMPZH)(2)].2(DMF).2(H(2)O) (3). In all of these compounds the tetranuclear cadmium array, containing two five-coordinate and two six-coordinate cadmium atoms, is held together by two mu(4) capping [ArPO(3)](2-) and four anisobidentate mu(2) [ArPO(2)(OH)](-) ligands. Each cadmium atom is bound to an additional ancillary ligand. The reaction of ArPO(3)H(2) with Cd(CH(3)COO)(2).2H(2)O in the presence of the chelating ligand 2,2'-bipyridine (bipy) leads to the exclusive formation of the dinuclear assembly [Cd(2)(ArPO(3)H)(4)(bipy)(2)].(CH(3)OH)(H(2)O) (4). The latter contains an eight-membered Cd(2)P(2)O(4) inorganic ring formed as a result of the bridging coordination action of two anisobidentate mu(2) [ArPO(2)(OH)](-) ligands. Each cadmium atom is bound by one chelating bipy and one monodentate [ArPO(2)(OH)](-) ligands. Use of four equivalents of 3,5-dimethylpyrazole leads to the formation of the mononuclear derivative [Cd(ArPO(3)H)(2)(DMPZH)(4)] (5). The molecular structure of the latter comprises of a central cadmium atom surrounded by six monodentate ligands. Four of these are neutral pyrazole ligands that occupy the equatorial plane; the remaining two are anionic phosphinate ligands which are present trans to each other. The thermal analysis of 1 and 4 reveals that the char residue obtained at 600 degrees C consists predominantly of Cd(2)P(2)O(7).

  2. The alien replicon: Artificial genetic constructs to direct the synthesis of transmissible self-replicating RNAs: In vivo synthesised heterologous (alien) RNA constructs are capable of initiating self-replication following transmission to the host organism.

    PubMed

    Kochetov, Alex V

    2014-12-01

    Artificial genetic constructs that direct the synthesis of self-replicating RNA molecules are used widely to induce gene silencing, for bioproduction, and for vaccination. Interestingly, one variant of the self-replicon has not been discussed in the literature: namely, transgenic organisms that synthesise alien replicons. For example, plant cells may be easily genetically modified to produce bacteriophages or insect viruses. Alien replicon-producing organisms (ARPOs) may serve as a unique tool for biocontrol or to selectively influence the characteristics of a target organism. The ARPO approach would have to meet strict biosafety criteria, and its practical applications are problematic. However, a discussion on ARPO applicability would be valuable to outline the full set of options available in the bioengineering toolbox. In this paper, RNA replicons for bioengineering are reviewed briefly, and the ARPO approach is discussed.

  3. Steinberg ``AUDIOMAPS" Music Appreciation-Via-Understanding: Special-Relativity + Expectations "Quantum-Theory": a Quantum-ACOUSTO/MUSICO-Dynamics (QA/MD)

    NASA Astrophysics Data System (ADS)

    Steinberg, R.; Siegel, E.

    2010-03-01

    ``AUDIOMAPS'' music enjoyment/appreciation-via-understanding methodology, versus art, music-dynamics evolves, telling a story in (3+1)-dimensions: trails, frames, timbres, + dynamics amplitude vs. music-score time-series (formal-inverse power- spectrum) surprisingly closely parallels (3+1)-dimensional Einstein(1905) special-relativity ``+'' (with its enjoyment- expectations) a manifestation of quantum-theory expectation- values, together a music quantum-ACOUSTO/MUSICO-dynamics (QA/MD). Analysis via Derrida deconstruction enabled Siegel- Baez ``Category-Semantics'' ``FUZZYICS''=``CATEGORYICS (``SON of 'TRIZ") classic Aristotle ``Square-of-Opposition" (SoO) DEduction-logic, irrespective of Boon-Klimontovich versus Voss- Clark[PRL(77)] music power-spectrum analysis sampling- time/duration controversy: part versus whole, shows that ``AUDIOMAPS" QA/MD reigns supreme as THE music appreciation-via- analysis tool for the listener in musicology!!! Connection to Deutsch-Hartmann-Levitin[This is Your Brain on Music,(2006)] brain/mind-barrier brain/mind-music connection is both subtle and compelling and immediate!!!

  4. Assembly of lipophilic tetranuclear (Cu4 and Zn4) molecular metallophosphonates from 2,4,6-triisopropylphenylphosponic acid and pyrazole ligands.

    PubMed

    Chandrasekhar, Vadapalli; Sasikumar, Palani; Boomishankar, Ramamoorthy; Anantharaman, Ganapathi

    2006-04-17

    A sterically hindered aryl phosphonic acid ArP(O)(OH)2 (2) (Ar = 2,4,6-isopropylphenyl) was synthesized and structurally characterized. ArP(O)(OH)2 forms an interesting hydrogen-bonded corrugated sheet-type supramolecular structure in the solid-state. A three-component reaction involving ArP(O)(OH)2, 3,5-dimethylpyrazole(DMPZH), and Cu(CH3COO)2.H2O produces the tetranuclear Cu(II) compound [Cu4(mu3-OH)2{ArPO2(OH)}2(CH3CO2)2(DMPZH)4][CH3COO]2.CH2Cl2 (3). A similar three-component reaction involving ArP(O)(OH)2, 3,5-dimethylpyrazole, and Zn(CH3COO)2.2H2O yields the tetranuclear Zn(II) compound [Zn4{ArPO3}2{ArPO2(OH)}2{DMPZH}4(DMPZ)2].5MeOH (4). While 3 has been found to have an asymmetric cage structure where two dinuclear copper cores are bridged by bidentate [ArPO2(OH)]- ligands, 4 possesses an open-book tricyclic structure composed of three fused metallophosphonate rings. Magnetic studies on 3 revealed antiferromagnetic behavior.

  5. Building Process Improvement Business Cases Using Bayesian Belief Networks and Monte Carlo Simulation

    DTIC Science & Technology

    2009-07-01

    specific organization. Others have tried to solve this problem with technologies to quantify expertise, such as Bayesian belief networks [ Bibi 2004...planning, control, and operational management of the process‖ [ Bibi 2004]. The paper shows a generalized model usable for effort estimation. With...make it impossible to deploy them at an organizational level [Neil 1996, Bibi 2004, Ziv 1997, Wooff 2002]. A usable model should include only the

  6. Israel: Background and Relations with the United States

    DTIC Science & Technology

    2010-01-07

    Likud party leader Benjamin “ Bibi ” Netanyahu, who was designated to form a government. Netanyahu put together a coalition comprising his own Likud...asked Bibi Netanyahu to form a government, giving him six weeks or until April 3 to find 61 votes in the Knesset in order to succeed. Netanyahu

  7. Somali Piracy: Are We Making a Mountain Out of a Molehill?

    DTIC Science & Technology

    2009-10-23

    http://ejscontent.ebsco.com/ (Accessed on 25 September 2009) 228. 12. Bibi van Ginkel, Jort Hemmer, Susanne Kamerling, and Frans-Paul van der...http://www.usip.org/files/resources/1_0.pdf (Accessed 28 August 2009). 31 Ginkel, Bibi van, Jort Hemmer, Susanne Kamerling, and Frans-Paul

  8. Phase-Sensitive Fluorescence Study of Mono-L-Aspartyl Chlorin E6

    DTIC Science & Technology

    2007-11-02

    of Science and Technology, 758-65 Bibi , Chitose, Hokkaido, 066-8655, Japan; 2 Meiji Seika Kaisha Limited, 760 Morooka-cho, Kohoku-ku, Yokohama, 222...Organization Name(s) and Address(es) Chitose Institute of Science and Technology, 758-65 Bibi , Chitose, Hokkaido, 066-8655, Japan Performing Organization

  9. COMPARISON OF TWO INDICES OF BENTHIC COMMUNITY CONDITION IN CHESAPEAKE BAY

    EPA Science Inventory

    The Chesapeake Benthic Index of Biotic Integrity (B-IBI) and the EMAP-VP Benthic Index were applied to samples from 239 sites in Chesapeake Bay. The B-IBI weights several community measures equally and uses a simple scoring system while the EMAP-VP Benthic Index uses discriminant...

  10. The Asia Pacific Rebalance: Tipping the Scale with Landpower

    DTIC Science & Technology

    2013-04-01

    partners from the more important discussion of an overall military strategy for the Asia-Pacific. As Michael O ” Hanlon and James Steinberg noted, 4...13 Ibid. 14 Michael O ” Hanlon and James Steinberg, “How Air-Sea Battle Fits in U.S. Planning,” Washington Post, August 24, 2012, http

  11. Least-desired index for assessing the effectiveness of grass riparian filter strips in improving water quality in an agricultural region.

    PubMed

    Kosnicki, Ely; Sites, Robert W

    2007-08-01

    Unprotected streams within the agricultural Midwest region of the United States are subject to sedimentation, nutrification, and agricultural chemicals. Grass riparian filter strips (GRFSs) have been implemented as a best management practice to minimize sedimentation and associated materials that are harmful to aquatic ecosystems; however, few studies have examined the benthic community response to GRFS installation. This study introduces a least-desired index (LDI) multimetric approach of evaluating benthic communities in response to GRFS installation. LDI was determined in a reciprocal fashion to that of a benthic macroinvertebrate index of biotic integrity (B-IBI). When reference conditions are not available for the use of B-IBI, anti-reference sites, representing least-desired conditions, can be used in constructing an LDI. A B-IBI and LDI were constructed in the Claypan Till Plains Subsection of Missouri and comparatively used to evaluate two test sites where tall fescue GRFS were installed. Five metrics were used to develop the B-IBI and six for the LDI. The LDI tended to be more conservative at evaluation in comparison to the B-IBI. Paired t-tests showed that LDI and B-IBI were significantly different at scoring test sites. The LDI assessed both test sites as showing no response to GRFS installation, whereas the B-IBI suggested moderate improvement. The LDI was considered to be a better index for evaluation because the streams used to develop the B-IBI were not suitable reference sites. An argument for the use of chironomid based metrics in low gradient agricultural streams is presented.

  12. Anti-Skywave AM Broadcast Antenna Design.

    DTIC Science & Technology

    1987-03-01

    Admiral R. C. Austin D . A. Schrady Superintendent Provost This thesis is prepared in conjunction with research sponscred in part by Naval Ocean Systems...I J ’ ~~~ D t 1 :-".. t 1-13 t . .. .. . . TABLE OF CONTENTS 1. INTRODUCTION .......................................... I I A. NEED FOR THE... D . SCOPE AND LIMITATIONS ............................. 13 II. THE ANALYSIS OF BIBY’S ANTI-SKYWAVE ANTENNA ......... 16 A. DESCRIPTION OF BIBY’S ANTI

  13. Predicting biological condition in southern California streams

    USGS Publications Warehouse

    Brown, Larry R.; May, Jason T.; Rehn, Andrew C.; Ode, Peter R.; Waite, Ian R.; Kennen, Jonathan G.

    2012-01-01

    As understanding of the complex relations among environmental stressors and biological responses improves, a logical next step is predictive modeling of biological condition at unsampled sites. We developed a boosted regression tree (BRT) model of biological condition, as measured by a benthic macroinvertebrate index of biotic integrity (BIBI), for streams in urbanized Southern Coastal California. We also developed a multiple linear regression (MLR) model as a benchmark for comparison with the BRT model. The BRT model explained 66% of the variance in B-IBI, identifying watershed population density and combined percentage agricultural and urban land cover in the riparian buffer as the most important predictors of B-IBI, but with watershed mean precipitation and watershed density of manmade channels also important. The MLR model explained 48% of the variance in B-IBI and included watershed population density and combined percentage agricultural and urban land cover in the riparian buffer. For a verification data set, the BRT model correctly classified 75% of impaired sites (B-IBI < 40) and 78% of unimpaired sites (B-IBI = 40). For the same verification data set, the MLR model correctly classified 69% of impaired sites and 87% of unimpaired sites. The BRT model should not be used to predict B-IBI for specific sites; however, the model can be useful for general applications such as identifying and prioritizing regions for monitoring, remediation or preservation, stratifying new bioassessments according to anticipated biological condition, or assessing the potential for change in stream biological condition based on anticipated changes in population density and development in stream buffers.

  14. Survey of residential and day schools for deaf students in the United States that identify themselves as bilingual-bicultural programs.

    PubMed

    LaSasso, Carol; Lollis, Jana

    2003-01-01

    The purpose of this survey was to determine how many residential and day schools for deaf and hard-of-hearing students in the United States described themselves as bilingual-bicultural (BiBi) programs and to describe characteristics of those programs related to initial implementation, whether a single language (e.g., English or ASL) is promoted as the first language (L1) and the language of instruction for all deaf students, how English is conveyed conversationally to deaf students, the quality of ASL abilities of BiBi instructional and support staff; general characteristics of the curriculum and the specific reading and bicultural components of the curriculum; and characteristics of research being conducted to establish the efficacy of BiBi methods. Ninety-one percent (n = 71) of the 78 day and residential schools listed in the 1998 Directory of the American Annals of the Deaf participated in the survey, with 19 schools identifying themselves as BiBi. These included 16 residential schools and 3 day schools. Depending on the source for numbers of students in residential and day schools at the time of the survey, between 36% and 40% of students were in programs that identified themselves as BiBi. Sixteen of the programs reported becoming a BiBi program between 1989 and 1994 and only three after 1994. Of the 19 programs, 37% reported use of manually coded English (MCE) for conveying English to the students. Fluency in ASL of instructional and support staff varied, with 47% of the programs reporting that no more than half of the instructional staff were fluent in ASL and 68% of the programs reporting that no more than half of the support staff were fluent. Only 21% of the 19 programs reported having a formal BiBi curriculum with annual goals and suggested materials and procedures for teachers. Research implications of these data are discussed.

  15. Rayleigh-Taylor Instability Growth Enigma: Liner Studies on Pegasus

    DTIC Science & Technology

    1999-06-01

    Conference, Vol. II, pg. 1399, ed. G. Cooperstein and I. Vitkovitsky, 1997. 5 D. Steinberg, " Equation of State and Strength Properties of Selected Materials ," UCRL-MA-106436, Feb. 13, 1996, Lawrence Livermore National Laboratory. 895

  16. What's In a Proton?

    ScienceCinema

    Brookhaven Lab

    2016-07-12

    Physicist Peter Steinberg explains that fundamental particles like protons are themselves made up of still smaller particles called quarks. He discusses how new particles are produced when quarks are liberated from protons...a process that can be observed

  17. Perminalized Alethopteris from the Upper Pennsylvanian of Ohio and Illinois

    SciTech Connect

    Mickle, J.E.; Rothwell, G.W.

    1982-03-01

    Fern-like foliage referable to Alethopteris Steinberg has been discovered in coal balls of Late Pennsylvanian age from near Staubenville, Ohio, and Berryville, Illinois. Pinnule morphology is described from specimens preserved on coal-ball surfaces.

  18. What's In a Proton?

    SciTech Connect

    Brookhaven Lab

    2009-07-08

    Physicist Peter Steinberg explains that fundamental particles like protons are themselves made up of still smaller particles called quarks. He discusses how new particles are produced when quarks are liberated from protons...a process that can be observed

  19. Electroproduction at very small values of the scaling variable

    NASA Astrophysics Data System (ADS)

    Bjorken, J. D.

    It is a real pleasure to dedicate these remarks to my colleague and friend, Jack Steinberger, whose work with neutrino production of hadrons has so much advanced our knowledge of the interior structure of the nucleon.

  20. Defense and Arms Control Studies Program, Annual Report 1992-1993

    DTIC Science & Technology

    1993-01-01

    and George Rathjens, "Nuclear Weapons After the Cold War," in Joseph Rotblat , Jack Steinberger, and Bhalchandra Udgaonkar, editors, A Nuclear- Weapon...February 1993). DEFENSE AND ARMS CONTROL STUDIES PROGRAM12 Marvin Miller and Jack Ruina, "The Breakout Problem," in Joseph Rotblat , Jack Steinberger, and...Aftermath October 14- ROBERT ALVAREZ U.S. Senate Committee on Governmental Affairs Disarmament and the U.S. Nuclear Cleanup October 21 - JOSEPH

  1. Restructuring Symbolic Programs for Concurrent Execution on Multiprocessors

    DTIC Science & Technology

    1989-05-01

    75 to analyze and restructure this program. The version of Boyer transformed by CURARE was translated into Scheme by Seth Steinberg of BBN. The...Graph. SIAM Journal of Computing, 1(2):131-137, June 1972. [3] Donald C. Allen, Seth A. Steinberg, and Lawrence A. Stabile. Recent Developments in...15(5):757-763, October 1966. [11] Philip A. Bernstein, David W. Shipman , and James B. Rothnie, Jr. Concurrency Control in a System for Distributed

  2. The National Security Council: An Organizational Assessment

    DTIC Science & Technology

    2009-06-08

    the NSC structure. 61 James Steinberg , “Foreign Policy: Time to Regroup,” Washington Post...68 See Steinberg , “Foreign Policy: Time to Regroup.” 69 For further background, see the PNSR website, http://www.pnsr.org. See also CRS Report...Service 32 Caraley, Demetrios. The Politics of Military Unification. New York: Columbia University Press. [1966]. Clark, Keith C., and Laurence S

  3. A Procedure to Detect Item Bias Present Simultaneously in Several Items

    DTIC Science & Technology

    1991-04-25

    response functions (IRFs) without the use of item parameter estimation algorithms when the sample size is too small for their use. Thissen, Steinberg ...Practice, 1992, Hillsdale, New Jersey: Erlbaum.) Thissen, D., Steinberg , L., and Wainer, H. (1988). Use of item response theory in the study of group...Paydhalog Depemen University of Tom Manpower support A 426 Frose P.O. Ba 19528 Readiness Prorsm Laurence , KS 66043 Arington. 7X 76019&028 Cente for Neva

  4. Generalized Measurement Models

    DTIC Science & Technology

    2005-06-27

    write A,B,C,D as linear functions of their parents: A = ∑ p apAp B = ∑ i biBi C = ∑ j cjCj D = ∑ k dkDk where on the right-hand side of each equation...B = ∑ i biBi C = ∑ j cjCj D = ∑ k dkDk where on the right-hand side of each equation the uppercase symbols denote the respective parents of each...error variance parameters. Proof: Suppose X1 and Y1 have a common parent L in G. Let X1 = aL + ∑ p apAp and Y1 = bL+ ∑ i biBi , where each Ap, Bi are

  5. Photocatalytic activities of coke carbon/g-C3N4 and Bi metal/Bi mixed oxides/g-C3N4 nanohybrids for the degradation of pollutants in wastewater

    PubMed Central

    Sierra, Marta; Borges, Emma; Esparza, Pedro; Méndez-Ramos, Jorge; Martín-Gil, Jesús; Martín-Ramos, Pablo

    2016-01-01

    Abstract Different g-C3N4 composite systems (coke carbon/g-C3N4, Bi/Bi2WO6/g-C3N4 and Bi/Bi2MoO6/g-C3N4) have been assessed as photocatalysts for wastewater pollutants removal. The coke carbon/g-C3N4 hybrid, produced by thermal treatment at 550 °C of a composite made from melamine cyanurate and coke, only showed activity under UV-light irradiation. On the other hand, inorganic Bi spheres/Bi mixed oxides/g-C3N4 nanohybrids (Bi/Bi2WO6/g-C3N4 and Bi/Bi2MoO6/g-C3N4 composites), produced by thermal reduction of Bi2WO6 or Bi2MoO6 by g-C3N4, exhibited a remarkable red-shift, up to 620 nm, and allowed the visible-light driven degradation of the contaminant, albeit in combination with some adsorption. PMID:27877912

  6. Photocatalytic activities of coke carbon/g-C3N4 and Bi metal/Bi mixed oxides/g-C3N4 nanohybrids for the degradation of pollutants in wastewater.

    PubMed

    Sierra, Marta; Borges, Emma; Esparza, Pedro; Méndez-Ramos, Jorge; Martín-Gil, Jesús; Martín-Ramos, Pablo

    2016-01-01

    Different g-C3N4 composite systems (coke carbon/g-C3N4, Bi/Bi2WO6/g-C3N4 and Bi/Bi2MoO6/g-C3N4) have been assessed as photocatalysts for wastewater pollutants removal. The coke carbon/g-C3N4 hybrid, produced by thermal treatment at 550 °C of a composite made from melamine cyanurate and coke, only showed activity under UV-light irradiation. On the other hand, inorganic Bi spheres/Bi mixed oxides/g-C3N4 nanohybrids (Bi/Bi2WO6/g-C3N4 and Bi/Bi2MoO6/g-C3N4 composites), produced by thermal reduction of Bi2WO6 or Bi2MoO6 by g-C3N4, exhibited a remarkable red-shift, up to 620 nm, and allowed the visible-light driven degradation of the contaminant, albeit in combination with some adsorption.

  7. Survey of Residential and Day Schools for Deaf Students in the United States that Identify Themselves as Bilingual-Bicultural Programs.

    ERIC Educational Resources Information Center

    LaSasso, Carol; Lollis, Jana

    2003-01-01

    A survey of 71 day and residential schools found 19 identified themselves as bilingual-bicultural (BiBi) programs. Of the 19 programs, 37% reported use of manually coded English. Fluency in American Sign Language of instructional and support staff varied, with 47% reporting no more than half of instructional staff were fluent. (Contains…

  8. Educating Deaf and Hearing Children in a Bilingual/Bicultural Environment.

    ERIC Educational Resources Information Center

    Saunders, Jacalyn

    1997-01-01

    Bilingual/bicultural (Bi/Bi) programs for children who are deaf are usually delivered via either transitional or maintenance models. Transitional models use the native language to teach a second language, whereas maintenance models teach and use both languages throughout the school day. There is a need for research into the effectiveness of BiBi…

  9. Application of the benthic index of biotic integrity to environmental monitoring in Chesapeake Bay.

    PubMed

    Llansó, Roberto J; Dauer, Daniel M; Vølstad, Jon H; Scott, Lisa C

    2003-01-01

    The Chesapeake Bay benthic index of biotic integrity (B-IBI) was developed to assess benthic community health and environmental quality in Chesapeake Bay. The B-IBI provides Chesapeake Bay monitoring programs with a uniform tool with which to characterize bay-wide benthic community condition and assess the health of the Bay. A probability-based design permits unbiased annual estimates of areal degradation within the Chesapeake Bay and its tributaries with quantifiable precision. However, of greatest interest to managers is the identification of problem areas most in need of restoration. Here we apply the B-IBI to benthic data collected in the Bay since 1994 to assess benthic community degradation by Chesapeake Bay Program segment and water depth. We used a new B-IBI classification system that improves the reliability of the estimates of degradation. Estimates were produced for 67 Chesapeake Bay Program segments. Greatest degradation was found in areas that are known to experience hypoxia or show toxic contamination, such as the mesohaline portion of the Potomac River, the Patapsco River, and the Maryland mainstem. Logistic regression models revealed increased probability of degraded benthos with depth for the lower Potomac River, Patapsco River. Nanticoke River, lower York River, and the Maryland mainstem. Our assessment of degradation by segment and water depth provided greater resolution of relative condition than previously available, and helped define the extent of degradation in Chesapeake Bay.

  10. JPRS Report. East Europe: Reference Aid, Abbreviations and Acronyms Used in the Bulgarian Press

    DTIC Science & Technology

    2007-11-02

    ArpoHOMHMecKH OaicyjiTeT agron. agronomist, agronomic Agr. fak. School of Agronomy Arc aBTOMaTHHeH ra30B CHrHajiH3aTop AGS automatic gas ...BHe3ariHH H3XBl>p.nHHHH Ha BTaTJlHlUa H ra3 VIVG sudden coal and gas ejection BH3 . BH3aHTHHCKH BM3BM BHCUI HHCTHTyT no 300TeXHHKa H...6H6jIHOrpa$CKH HHCTHTyT g. year year, annual issue (periodicals and newspapers) j | G, g gram [use g] g- group GA generator set, genset GA

  11. Parental Characteristics, Ecological Factors, and the Academic Achievement of African American Males

    ERIC Educational Resources Information Center

    Hines, Erik M.; Holcomb-McCoy, Cheryl

    2013-01-01

    Parental characteristics, ecological factors, and the academic achievement of African American male high school students were examined. One hundred fifty-three 11th and 12th grade African American males completed the Parenting Style Index (Steinberg, Lamborn, Darling, Mounts, & Dornbusch, 1994) and a demographic questionnaire. Results…

  12. Annual Review of Applied Linguistics, Volume 5, 1984.

    ERIC Educational Resources Information Center

    Kaplan, Robert B., Ed.

    This volume of the annual review includes introductory remarks by G. Richard Tucker and these papers: "Current Issues in Bilingualism: An Update of Directions in Research" (Braj B. Kachru); "Psycholinguistics: Application. The Writing System as a Native Language for the Deaf" (Danny D. Steinberg); "Sociolinguistics: Theory" (Monica Heller);…

  13. Job Training for Women: The Promise and Limits of Public Policies. Women in the Political Economy Series.

    ERIC Educational Resources Information Center

    Harlan, Sharon L., Ed.; Steinberg, Ronnie J., Ed.

    This comprehensive review of the public system of occupational education and job training for women in the United States focuses on education and training for occupations that require less than a four-year college degree. Chapter 1, "Job Training for Women: The Problem in a Policy Context" (Harlan, Steinberg), sketches an outline of job training…

  14. Viral Immunotherapy to Eradicate Subclinical Brain Metastases

    DTIC Science & Technology

    2014-05-01

    Cells. Journal of Immunology. 2013; 191(1):17-23. 24. Schmieder A, Michel J, Schonhaar K, Goerdt S, Schledzewski K. Differentiation and gene expression...Steinberg B, Barron D. Changes in peripheral T-cell subsets and natural-killer cytotoxicity in relation to colorec- tal cancer surgery. Cancer

  15. The MA in Writing at DePaul University

    ERIC Educational Resources Information Center

    Clary-Lemon, Jennifer; Vandenberg, Peter

    2006-01-01

    While discussion about the nature and function of the PhD has flourished for years in the broad context of English studies (Bérubé; Lunsford et al.; Nelson) and for more than a decade now in rhetoric and composition (Brown, Meyer, and Enos; North; Young and Steinberg), the Master's degree has attracted scant attention. No doubt this traces to a…

  16. Different Reproductive Strategies in Males and Females.

    ERIC Educational Resources Information Center

    Maccoby, Eleanor E.

    1991-01-01

    Comments on Belsky, Steinberg, and Draper's article in this issue. Discusses the claim for a connection of stressful childhood environments and early pubertal maturation. Argues that early puberty need not imply a shift from a "quality" toward a "quantity" reproductive strategy and that nonevolutionary factors can account for…

  17. When Is an Evolutionary Approach Useful?

    ERIC Educational Resources Information Center

    Hinde, Robert A.

    1991-01-01

    Comments on Belsky, Steinberg, and Draper's article in this issue. Offers three likely reasons for adaptation of human behavior. Argues that Belsky, et al. use only two of these reasons in their proposed evolutionary theory of socialization. Suggests that an evolutionary approach is useful if it integrates diverse facts, aids clinical practice,…

  18. The Development of Reproductive Strategy in Females: Early Maternal Harshness [right arrow] Earlier Menarche [right arrow] Increased Sexual Risk Taking

    ERIC Educational Resources Information Center

    Belsky, Jay; Steinberg, Laurence; Houts, Renate M.; Halpern-Felsher, Bonnie L.

    2010-01-01

    To test a proposition central to J. Belsky, L. Steinberg, and P. Draper's (1991) evolutionary theory of socialization--that pubertal maturation plays a role in linking early rearing experience with adolescent sexual risk taking (i.e., frequency of sexual behavior) and, perhaps, other risk taking (e.g., alcohol, drugs, delinquency)--the authors…

  19. Dynamic Deformation of a Solenoid Wire Due to Internal Magnetic Pressure

    DTIC Science & Technology

    2001-06-01

    high-strain rate”, J. Appl. Phys., vol 51, pp. 1498-1504, 1980. [10] D. J. Steinberg, “ Equation of state and strength properties of selected materials (revised)” LLNL, Livermore, CA, Tech. Rep. UCRL-MA-106439, change 1, Feb 1996.

  20. The Other Side of the Story: Israeli and Palestinian Teachers Write a History Textbook Together

    ERIC Educational Resources Information Center

    Steinberg, Shoshana; Bar-On, Dan

    2009-01-01

    In this essay, Shoshana Steinberg and Dan Bar-On present the work of a team of Israeli and Palestinian teachers who developed a history textbook that includes both groups' narratives of the same events side by side. These teachers then tested the effects of its use in both Israeli and Palestinian classrooms; for the first time, students on each…

  1. Selling Out (In) Sport Management: Practically Evaluating the State of the American (Sporting) Union

    ERIC Educational Resources Information Center

    Wiest, Amber; King-White, Ryan

    2013-01-01

    When teaching in Sport Management programs professors are often forced to respond to the actions and teachings of professionals in the field. According to the study by Kincheloe & Steinberg many of these normalized and, indeed celebrated, behaviors are actions that are part and parcel of the "recovery movement" which (re)inscribe new…

  2. Parental Relationships, Autonomy, and Identity Processes of High School Students

    ERIC Educational Resources Information Center

    Mullis, Ronald L.; Graf, Shruti Chatterjee; Mullis, Ann K.

    2009-01-01

    To examine the interrelations among parental relationships, emotional autonomy, and identity statuses, the authors asked 234 (105 male, 129 female) high school students to complete the Parental Bonding Scale (G. Parker, H. Tupling, & L. B. Brown, 1979), Emotional Autonomy Scale (L. D. Steinberg & S. B. Silverberg, 1986), and Extended Objective…

  3. Addressing gaps in the maturity of judgment literature: age differences and delinquency.

    PubMed

    Modecki, Kathryn Lynn

    2008-02-01

    Over the past decade, a majority of states have legislated to expand their capacity to try adolescents as adults [Griffin (2003). Trying and sentencing juveniles as adults: An analysis of state transfer and blended sentencing laws. Pittsburgh, PA: National Center for Juvenile Justice]. In response, researchers have investigated factors that may affect adolescent culpability [Steinberg and Scott (Am Psychol 58(12):1009-1018, 2003)]. Research on immature judgment posits that psychosocial influences on adolescent decision processes results in reduced criminal responsibility [Cauffman and Steinberg (Behav Sci Law 18(6):741-760, 2000); Scott, Reppucci, and Woolard (Law Hum Behav 19(3):221-244, 1995); Steinberg and Cauffman (Law Hum Behav 20(3):249-272, 1996)]. The current study utilizes hypothetical vignettes and standardized measures of maturity of judgment (responsibility, temperance, and perspective) to examine gaps in previous maturity of judgment findings (Cauffman and Steinberg 2000). This work suggests that adolescents (ages 14-17) display less responsibility and perspective relative to college students (ages 18-21), young-adults (ages 22-27), and adults (ages 28-40). Further, this research finds no maturity of judgment differences between delinquent and non-delinquent youth, but does find significant maturity of judgment differences between high and low delinquency male youth. Finally, results show that maturity of judgment predicts self-reported delinquency beyond the contributions of age, gender, race, education level, SES, and antisocial decision making. Implications for the juvenile justice system are discussed.

  4. Youth Violence: Do Parents and Families Make a Difference?

    ERIC Educational Resources Information Center

    Steinberg, Laurence

    2000-01-01

    This article is an adaptation of the authors statement to the U.S. House of Representatives Bipartisan Working Group on Youth Violence on September 15, 1999. Specifically, the Working Group asked Dr. Steinberg, an adolescent behavior researcher, to address issues concerning the role of parents and families in the genesis and prevention of youth…

  5. Adolescent Development and the Regulation of Youth Crime

    ERIC Educational Resources Information Center

    Scott, Elizabeth S.; Steinberg, Laurence

    2008-01-01

    Elizabeth Scott and Laurence Steinberg explore the dramatic changes in the law's conception of young offenders between the end of the nineteenth century and the beginning of the twenty-first. At the dawn of the juvenile court era, they note, most youths were tried and punished as if they were adults. Early juvenile court reformers argued strongly…

  6. Photon tracking scoops Physics World award

    NASA Astrophysics Data System (ADS)

    Johnston, Hamish

    2012-01-01

    The 2011 Physics World Breakthrough of the Year has been awarded to Aephraim Steinberg and colleagues from the University of Toronto in Canada, who have, for the first time, tracked the average paths of single photons passing through a Young's double-slit experiment.

  7. King of Cool

    ERIC Educational Resources Information Center

    Freado, Mark; Van Bockern, Steve

    2010-01-01

    Many teenagers get involved in criminal activity. This tendency is so pervasive that psychologist Terrie Moffitt, one of the world's leading experts on the development of antisocial behavior, has described delinquent behavior as a normal part of teenager life (Scott & Steinberg, 2008). Adults, even those in the justice system, are often at a loss…

  8. Comment and Response.

    ERIC Educational Resources Information Center

    College English, 1987

    1987-01-01

    Contains (1) A Comment on "Protocols, Retrospective Reports, and the Stream of Consciousness" (Victor J. Vitanza); (2) "Erwin R. Steinberg Responds"; (3) A Comment on "Intertextuality and the Cultural Text in Recent Semiotics" (Stephen Kogan); and (4) Two Comments on "College English" (Kenneth E. Eble, Jean…

  9. King of Cool

    ERIC Educational Resources Information Center

    Freado, Mark; Van Bockern, Steve

    2010-01-01

    Many teenagers get involved in criminal activity. This tendency is so pervasive that psychologist Terrie Moffitt, one of the world's leading experts on the development of antisocial behavior, has described delinquent behavior as a normal part of teenager life (Scott & Steinberg, 2008). Adults, even those in the justice system, are often at a loss…

  10. Beyond Authoritarianism: A Cultural Perspective on Asian American Parenting Practices.

    ERIC Educational Resources Information Center

    Chao, Ruth K.

    A study was conducted to determine Asian American conceptualizations of parenting, focusing on socialization goals, parenting style, and parenting practices related to schooling, aspects of parental influences discussed by D. Darling and L. Steinberg (1993). It was suggested that the standard conceptualizations of parenting style, those of D.…

  11. Preventing Adolescent Drug Use: From Theory to Practice. OSAP Prevention Monograph-8.

    ERIC Educational Resources Information Center

    Goplerud, Eric N., Ed.

    This monograph provides a framework for communities to build and evaluate adolescent drug abuse prevention programs. The first chapter "Adolescent Transitions and Alcohol and Other Drug Use Prevention," by Laurence Steinberg, focuses on the biological, cognitive, and psychosocial transitions of adolescence and how this knowledge can be used to…

  12. Adolescents' Perceptions of Parental Goals, Practices, and Styles in Relation to Their Motivation and Achievement

    ERIC Educational Resources Information Center

    Spera, Christopher

    2006-01-01

    The current study examines research questions proposed by an expanded version of Darling and Steinberg's contextual model of parenting. Using a sample of 184 adolescents, the analyses indicated that adolescents' perceptions of parental educational goals and values were related positively and significantly to their reports of parental school…

  13. Revisiting the Impact of Part-Time Work on Adolescent Adjustment: Distinguishing between Selection and Socialization Using Propensity Score Matching

    ERIC Educational Resources Information Center

    Monahan, Kathryn C.; Lee, Joanna M.; Steinberg, Laurence

    2011-01-01

    The impact of part-time employment on adolescent functioning remains unclear because most studies fail to adequately control for differential selection into the workplace. The present study reanalyzes data from L. Steinberg, S. Fegley, and S. M. Dornbusch (1993) using multiple imputation, which minimizes bias in effect size estimation, and 2 types…

  14. Reconciling the Complexity of Human Development with the Reality of Legal Policy: Reply to Fischer, Stein, and Heikkinen (2009)

    ERIC Educational Resources Information Center

    Steinberg, Laurence; Cauffman, Elizabeth; Woolard, Jennifer; Graham, Sandra; Banich, Marie

    2009-01-01

    The authors respond to both the general and specific concerns raised in Fischer, Stein, and Heikkinen's commentary on their article (Steinberg, Cauffman, Woolard, Graham, & Banich), in which they drew on studies of adolescent development to justify the American Psychological Association's positions in two Supreme Court cases involving the…

  15. Parents.

    ERIC Educational Resources Information Center

    Hurst, Hunter, Ed.; And Others

    1986-01-01

    This document contains the fifth volume of "Today's Delinquent," an annual publication of the National Center for Juvenile Justice. This volume deals with the issue of the family and delinquency, examining the impact of parental behavior on the production of delinquent behavior. "Parents: Neglectful and Neglected" (Laurence D. Steinberg) posits…

  16. Remediation in Higher Education. A Symposium Featuring "Remedial Education: Costs and Consequences."

    ERIC Educational Resources Information Center

    Breneman, David W.; Haarlow, William N.

    1998-01-01

    This symposium report consists of a 22-page report by Breneman and Haarlow, followed by 28 pages containing separate commentaries by Robert M. Costrell, David H. Ponitz, and Laurence Steinberg, respectively. The report builds on earlier research into the costs of remedial education as it relates to the total higher education expenditures in the…

  17. Premature Dissemination of Advice Undermines Our Credibility as Scientists: Reply to Brown (2011) and to Collins, Martino, and Elliott (2011)

    ERIC Educational Resources Information Center

    Steinberg, Laurence; Monahan, Kathryn C.

    2011-01-01

    In our reanalysis of data from the Brown et al. (2006) study (Steinberg & Monahan, 2011), we found no support for the contention that adolescents' exposure to sexy media content hastens their sexual debut. In their critiques of our article, Brown (2011) and Collins, Martino, and Elliott (2011) both questioned some of the decisions we made with…

  18. VLF Source Localization with a Freely Drifting Sensor Array

    DTIC Science & Technology

    1992-09-01

    Chair Professor LeRoy M. Dorman Professor John A. Hildebrand Professor Laurence B. Milstein Professor James R. Zeidler 1992 TABLE OF CONTENTS TA...VLF acoustic data [ Steinberg , 1976]. Table 3.12 Average float speed, July 1989 experiment. Average Float Number Speed (meters/hour) 0 350 1 170 2 220 3

  19. Detection of Atmospheric Carbon Dioxide from a Shuttle-Borne Lidar.

    DTIC Science & Technology

    1982-12-01

    Program. NAS3FSP-433. Washingtion, DC: Langley Research Center, NASA, 1979. . 8. Albanese, A.S. and M. Steinberg . Environmental Control Technolog for...1978. 30. Rothman, L.S. et al. "AFGL Trace Gas Compilation: 1980 Version," Appl:ed- ptics, 20: 1323-1328 (April 1981). 31. Rothman, Laurence S. and

  20. Motivation to Learn and Teacher-Student Relationship

    ERIC Educational Resources Information Center

    Koca, Fatih

    2016-01-01

    When children enter school for the first time, they encounter a variety of new challenges that include creating positive relationships with peer groups and adults as well as learning to meet the demands of a wide range of cognitive, social, and academic tasks (Baker, 2006; Birch & Ladd, 1997; Pianta, Steinberg, & Rollins, 1995). Infants…

  1. Review of Pearson Test of English Academic: Building an Assessment Use Argument

    ERIC Educational Resources Information Center

    Wang, Huan; Choi, Ikkyu; Schmidgall, Jonathan; Bachman, Lyle F.

    2012-01-01

    This review departs from current practice in reviewing tests in that it employs an "argument-based approach" to test validation to guide the review (e.g. Bachman, 2005; Kane, 2006; Mislevy, Steinberg, & Almond, 2002). Specifically, it follows an approach to test development and use that Bachman and Palmer (2010) call the process of "assessment…

  2. Model Diagnostics for Bayesian Networks. Research Report. ETS RR-04-17

    ERIC Educational Resources Information Center

    Sinharay, Sandip

    2004-01-01

    Assessing fit of psychometric models has always been an issue of enormous interest, but there exists no unanimously agreed upon item fit diagnostic for the models. Bayesian networks, frequently used in educational assessments (see, for example, Mislevy, Almond, Yan, & Steinberg, 2001) primarily for learning about students' knowledge and…

  3. Further Thoughts on "How Task Features Impact Evidence from Assessments Embedded in Simulations and Games"

    ERIC Educational Resources Information Center

    Oliveri, María Elena; Khan, Saad

    2014-01-01

    María Oliveri, and Saad Khan write that the article: "How Task Features Impact Evidence from Assessments Embedded in Simulations and Games" provided helpful illustrations regarding the implementation of evidence-centered assessment design (Mislevy & Haertel, 2006; Mislevy, Steinberg, & Almond, 1999) with games and simulations.…

  4. 410th Brookhaven Lecture

    SciTech Connect

    Peter Steinberg

    2005-12-21

    In a lecture titled "Hotter, Denser, Faster, Smaller...and Nearly Perfect: What's the Matter at RHIC?", Steinberg discusses the basic physics of the quark-gluon plasma and BNL's Relativistic Heavy Ion Collider, with a focus on several intriguing results from RHIC's recently ended PHOBOS experiment.

  5. Parental Characteristics, Ecological Factors, and the Academic Achievement of African American Males

    ERIC Educational Resources Information Center

    Hines, Erik M.; Holcomb-McCoy, Cheryl

    2013-01-01

    Parental characteristics, ecological factors, and the academic achievement of African American male high school students were examined. One hundred fifty-three 11th and 12th grade African American males completed the Parenting Style Index (Steinberg, Lamborn, Darling, Mounts, & Dornbusch, 1994) and a demographic questionnaire. Results…

  6. Academic Value of Non-Academics: The Case for Keeping Extracurriculars

    ERIC Educational Resources Information Center

    Kronholz, June

    2012-01-01

    A growing body of research says there is a link between afterschool activities and graduating from high school, going to college, and becoming a responsible citizen. Temple University psychologist Laurence Steinberg, whose book, "You and Your Adolescent: The Essential Guide for Ages 10-25," discusses afterschool activities. He suggested…

  7. Autonomy, Educational Plans, and Self-Esteem in Institution-Reared and Home-Reared Teenagers in Estonia

    ERIC Educational Resources Information Center

    Tulviste, Tiia

    2011-01-01

    The study examines autonomy, self-esteem, and educational plans for the future of 109 institution-reared and 106 home-reared teenagers (15-19 years). Teenagers were asked to complete the Teen Timetable Scale (Feldman & Rosenthal), two Emotional Autonomy Scales (Steinberg & Silverberg), the Rosenberg Self-Esteem Scale, and answer questions…

  8. Will There Always be an English?

    ERIC Educational Resources Information Center

    Henry, George H.

    1972-01-01

    A critical review of English Education Today," edited by L.S. Josephs and E. R. Steinberg, which is more a review of English curriculum, the directions, philosophies, and problems in English instruction, with emphasis on the need to think critically and innovatively. (JB)

  9. Premature Dissemination of Advice Undermines Our Credibility as Scientists: Reply to Brown (2011) and to Collins, Martino, and Elliott (2011)

    ERIC Educational Resources Information Center

    Steinberg, Laurence; Monahan, Kathryn C.

    2011-01-01

    In our reanalysis of data from the Brown et al. (2006) study (Steinberg & Monahan, 2011), we found no support for the contention that adolescents' exposure to sexy media content hastens their sexual debut. In their critiques of our article, Brown (2011) and Collins, Martino, and Elliott (2011) both questioned some of the decisions we made with…

  10. Further Thoughts on "How Task Features Impact Evidence from Assessments Embedded in Simulations and Games"

    ERIC Educational Resources Information Center

    Oliveri, María Elena; Khan, Saad

    2014-01-01

    María Oliveri, and Saad Khan write that the article: "How Task Features Impact Evidence from Assessments Embedded in Simulations and Games" provided helpful illustrations regarding the implementation of evidence-centered assessment design (Mislevy & Haertel, 2006; Mislevy, Steinberg, & Almond, 1999) with games and simulations.…

  11. Review of Pearson Test of English Academic: Building an Assessment Use Argument

    ERIC Educational Resources Information Center

    Wang, Huan; Choi, Ikkyu; Schmidgall, Jonathan; Bachman, Lyle F.

    2012-01-01

    This review departs from current practice in reviewing tests in that it employs an "argument-based approach" to test validation to guide the review (e.g. Bachman, 2005; Kane, 2006; Mislevy, Steinberg, & Almond, 2002). Specifically, it follows an approach to test development and use that Bachman and Palmer (2010) call the process of "assessment…

  12. 19 Urban Questions: Teaching in the City. Second Edition. Counterpoints: Studies in Postmodern Theory of Education, Vol. 215

    ERIC Educational Resources Information Center

    Steinberg, Shirley R., Ed

    2010-01-01

    The second edition of "19 Urban Questions: Teaching in the City" adds new questions to those in the original volume. Continuing the developing conversation in urban education, the book is provocative in style and rich in detail. Emphasizing the complexity of urban education, Shirley R. Steinberg and the authors ask direct questions about what…

  13. The Literacy Issue: Feminist Perspectives on Reading and Writing.

    ERIC Educational Resources Information Center

    Turner, Susan, Ed.

    1990-01-01

    A special issue of a journal devoted to women's literacy education contains the following articles: "Literacy: A Tool for Empowerment of Women?" (Agneta Lind); "Khulumani Makhosikazi: Women and Literacy...Some South African Women Speak" (Dawn Norton, Carola Steinberg); "Tomorrow Will Be Different: A Literacy Course for…

  14. Literacy Update. Volume 18, Number 4

    ERIC Educational Resources Information Center

    Steinberg, Jon, Ed.

    2009-01-01

    This newsletter, published five times a year, features articles on issues of concern to adult, family, and youth literacy practitioners, as well as recommended resources, announcements, and teaching strategies. This issue includes: (1) Career Pathways for High School Dropouts: A National Survey (Jon Steinberg); (2) Work (Elyse Barbell); (3) Peer…

  15. Literacy Update. Volume 18, Number 3

    ERIC Educational Resources Information Center

    Steinberg, Jon, Ed.

    2009-01-01

    This newsletter, published five times a year, features articles on issues of concern to adult, family, and youth literacy practitioners, as well as recommended resources, announcements, and teaching strategies. This issue includes: (1) Pushing for Change (Jon Steinberg); (2) Putting the GED to Work (Jill Poklemba); (3) Community Education Pathways…

  16. Literacy Update. Volume 18, Number 3

    ERIC Educational Resources Information Center

    Steinberg, Jon, Ed.

    2009-01-01

    This newsletter, published five times a year, features articles on issues of concern to adult, family, and youth literacy practitioners, as well as recommended resources, announcements, and teaching strategies. This issue includes: (1) Pushing for Change (Jon Steinberg); (2) Putting the GED to Work (Jill Poklemba); (3) Community Education Pathways…

  17. Emotional Autonomy versus Susceptibility to Peer Pressure: A Case Study of Hong Kong Adolescent Students

    ERIC Educational Resources Information Center

    Chan, Kwok-Wai; Chan, Siu-Mui

    2008-01-01

    A questionnaire consisting of two scales was administered to 550 Hong Kong secondary students to examine their emotional autonomy and susceptibility to peer pressure. Emotional autonomy was studied by the scale (EAS) developed by Steinberg and Silverberg (1986) and susceptibility to peer pressure was studied by the scale developed by Sim and Koh…

  18. Acts of God - The Unnatural History of Natural Disaster in America

    NASA Astrophysics Data System (ADS)

    Steinberg, Ted

    2003-05-01

    With the exception of the 9/11 disaster, the top ten most costly catastrophes in U.S. history have all been natural disasters--five of them hurricanes--and all have occurred since 1989. Why this tremendous plague on our homes? In Acts of God , environmental historian Ted Steinberg explains that much of the death and destruction has been well within the realm of human control. Steinberg exposes the fallacy of seeing such calamities as simply random events. Beginning with the 1886 Charleston and 1906 San Francisco earthquakes, and continuing to the present, Steinberg explores the unnatural history of natural calamity, the decisions of business leaders and government officials that have paved the way for the greater losses of life and property, especially among those least able to withstand such blows--America's poor, elderly, and minorities. Seeing nature or God as the primary culprit, Steinberg argues, has helped to hide the fact that some Americans are better protected from the violence of nature than their counterparts lower down the socioeconomic ladder. Sure to provoke discussion, Acts of God is a call to action that must be heard. "A sobering lesson in humanity's vulnerability to extreme climatic events, especially the impoverished farmer and the urban poor."--The Los Angeles Times Book Review

  19. Reciprocal Relations between Perceived Parental Knowledge and Adolescent Substance Use and Delinquency: The Moderating Role of Parent-Teen Relationship Quality

    ERIC Educational Resources Information Center

    Abar, Caitlin C.; Jackson, Kristina M.; Wood, Mark

    2014-01-01

    The current study prospectively examined hypothesized short- and long-term reciprocal relations between perceived parental knowledge and adolescent heavy episodic drinking, marijuana use, and delinquency. Using the contextual model of parenting style (Darling & Steinberg, 1993), we examined the extent to which the bidirectional nature of…

  20. Reciprocal Relations between Perceived Parental Knowledge and Adolescent Substance Use and Delinquency: The Moderating Role of Parent-Teen Relationship Quality

    ERIC Educational Resources Information Center

    Abar, Caitlin C.; Jackson, Kristina M.; Wood, Mark

    2014-01-01

    The current study prospectively examined hypothesized short- and long-term reciprocal relations between perceived parental knowledge and adolescent heavy episodic drinking, marijuana use, and delinquency. Using the contextual model of parenting style (Darling & Steinberg, 1993), we examined the extent to which the bidirectional nature of…

  1. Parental Relationships, Autonomy, and Identity Processes of High School Students

    ERIC Educational Resources Information Center

    Mullis, Ronald L.; Graf, Shruti Chatterjee; Mullis, Ann K.

    2009-01-01

    To examine the interrelations among parental relationships, emotional autonomy, and identity statuses, the authors asked 234 (105 male, 129 female) high school students to complete the Parental Bonding Scale (G. Parker, H. Tupling, & L. B. Brown, 1979), Emotional Autonomy Scale (L. D. Steinberg & S. B. Silverberg, 1986), and Extended Objective…

  2. Revisiting the Impact of Part-Time Work on Adolescent Adjustment: Distinguishing between Selection and Socialization Using Propensity Score Matching

    ERIC Educational Resources Information Center

    Monahan, Kathryn C.; Lee, Joanna M.; Steinberg, Laurence

    2011-01-01

    The impact of part-time employment on adolescent functioning remains unclear because most studies fail to adequately control for differential selection into the workplace. The present study reanalyzes data from L. Steinberg, S. Fegley, and S. M. Dornbusch (1993) using multiple imputation, which minimizes bias in effect size estimation, and 2 types…

  3. Academic Value of Non-Academics: The Case for Keeping Extracurriculars

    ERIC Educational Resources Information Center

    Kronholz, June

    2012-01-01

    A growing body of research says there is a link between afterschool activities and graduating from high school, going to college, and becoming a responsible citizen. Temple University psychologist Laurence Steinberg, whose book, "You and Your Adolescent: The Essential Guide for Ages 10-25," discusses afterschool activities. He suggested…

  4. Emotional Autonomy versus Susceptibility to Peer Pressure: A Case Study of Hong Kong Adolescent Students

    ERIC Educational Resources Information Center

    Chan, Kwok-Wai; Chan, Siu-Mui

    2008-01-01

    A questionnaire consisting of two scales was administered to 550 Hong Kong secondary students to examine their emotional autonomy and susceptibility to peer pressure. Emotional autonomy was studied by the scale (EAS) developed by Steinberg and Silverberg (1986) and susceptibility to peer pressure was studied by the scale developed by Sim and Koh…

  5. Designing across Ages: Multi-Agent-Based Models and Learning Electricity

    ERIC Educational Resources Information Center

    Sengupta, Pratim

    2009-01-01

    Electricity is regarded as one of the most challenging topics for students at all levels--middle school--college (Cohen, Eylon, & Ganiel, 1983; Belcher & Olbert, 2003; Eylon & Ganiel, 1990; Steinberg et al., 1985). Several researchers have suggested that naive misconceptions about electricity stem from a deep incommensurability (Slotta & Chi,…

  6. Designing across Ages: Multi-Agent-Based Models and Learning Electricity

    ERIC Educational Resources Information Center

    Sengupta, Pratim

    2009-01-01

    Electricity is regarded as one of the most challenging topics for students at all levels--middle school--college (Cohen, Eylon, & Ganiel, 1983; Belcher & Olbert, 2003; Eylon & Ganiel, 1990; Steinberg et al., 1985). Several researchers have suggested that naive misconceptions about electricity stem from a deep incommensurability (Slotta & Chi,…

  7. Joe L. Kincheloe: Genies and Wishes--A Review of "Key Works in Critical Pedagogy"

    ERIC Educational Resources Information Center

    Ali-Khan, Carolyne; Siry, Christina

    2012-01-01

    We review "Key Works in Critical Pedagogy: Joe L. Kincheloe" edited by Kecia Hayes, Shirley R. Steinberg and Kenneth Tobin, which gathers the seminal works of Joe. L. Kincheloe and pairs them with contemporary scholars who respond to and push forward Kincheloe's work. The chapters of "Key Works in Critical Pedagogy" are arranged to begin with…

  8. In praise of weakness

    NASA Astrophysics Data System (ADS)

    Steinberg, Aephraim; Feizpour, Amir; Rozema; Mahler; Hayat

    2013-03-01

    Quantum physics is being transformed by a radical new conceptual and experimental approach known as weak measurement that can do everything from tackling basic quantum mysteries to mapping the trajectories of photons in a Young's double-slit experiment. Aephraim Steinberg, Amir Feizpour, Lee Rozema, Dylan Mahler and Alex Hayat unveil the power of this new technique.

  9. Groups graded by root systems and property (T)

    PubMed Central

    Ershov, Mikhail; Jaikin-Zapirain, Andrei; Kassabov, Martin; Zhang, Zezhou

    2014-01-01

    We establish property (T) for a large class of groups graded by root systems, including elementary Chevalley groups and Steinberg groups of rank at least 2 over finitely generated commutative rings with 1. We also construct a group with property (T) which surjects onto all finite simple groups of Lie type and rank at least two. PMID:25425669

  10. Comment and Response.

    ERIC Educational Resources Information Center

    College English, 1987

    1987-01-01

    Contains (1) A Comment on "Protocols, Retrospective Reports, and the Stream of Consciousness" (Victor J. Vitanza); (2) "Erwin R. Steinberg Responds"; (3) A Comment on "Intertextuality and the Cultural Text in Recent Semiotics" (Stephen Kogan); and (4) Two Comments on "College English" (Kenneth E. Eble, Jean…

  11. Relationships between Adolescent Sexual Outcomes and Exposure to Sex in Media: Robustness to Propensity-Based Analysis

    ERIC Educational Resources Information Center

    Collins, Rebecca L.; Martino, Steven C.; Elliott, Marc N.; Miu, Angela

    2011-01-01

    Adolescent sexual health is a substantial problem in the United States, and two recent studies have linked adolescent sexual behavior and/or outcomes to youths' exposure to sex in the media. Both studies had longitudinal survey designs and used covariate-adjusted regression analysis. Steinberg and Monahan (2011) reanalyzed data from one of these…

  12. Funding Ammunition Ports

    DTIC Science & Technology

    2012-01-01

    CRM D0020940.A2/Final, December 2009. Brauner, Marygail K., Ellen M. Pint, John R. Bondanella, Daniel A. Relles, and Paul Steinberg , Dollars and Sense...2011: http://www.dau.mil/pubscats/PubsCats/Hanks.pdf Hirshleifer, Jack , “On the Economics of Transfer Pricing,” The Journal of Business, Vol. 29, No. 3

  13. 19 Urban Questions: Teaching in the City. Second Edition. Counterpoints: Studies in Postmodern Theory of Education, Vol. 215

    ERIC Educational Resources Information Center

    Steinberg, Shirley R., Ed

    2010-01-01

    The second edition of "19 Urban Questions: Teaching in the City" adds new questions to those in the original volume. Continuing the developing conversation in urban education, the book is provocative in style and rich in detail. Emphasizing the complexity of urban education, Shirley R. Steinberg and the authors ask direct questions about what…

  14. Autonomy, Educational Plans, and Self-Esteem in Institution-Reared and Home-Reared Teenagers in Estonia

    ERIC Educational Resources Information Center

    Tulviste, Tiia

    2011-01-01

    The study examines autonomy, self-esteem, and educational plans for the future of 109 institution-reared and 106 home-reared teenagers (15-19 years). Teenagers were asked to complete the Teen Timetable Scale (Feldman & Rosenthal), two Emotional Autonomy Scales (Steinberg & Silverberg), the Rosenberg Self-Esteem Scale, and answer questions…

  15. Selling Out (In) Sport Management: Practically Evaluating the State of the American (Sporting) Union

    ERIC Educational Resources Information Center

    Wiest, Amber; King-White, Ryan

    2013-01-01

    When teaching in Sport Management programs professors are often forced to respond to the actions and teachings of professionals in the field. According to the study by Kincheloe & Steinberg many of these normalized and, indeed celebrated, behaviors are actions that are part and parcel of the "recovery movement" which (re)inscribe new…

  16. 410th Brookhaven Lecture

    ScienceCinema

    Peter Steinberg

    2016-07-12

    In a lecture titled "Hotter, Denser, Faster, Smaller...and Nearly Perfect: What's the Matter at RHIC?", Steinberg discusses the basic physics of the quark-gluon plasma and BNL's Relativistic Heavy Ion Collider, with a focus on several intriguing results from RHIC's recently ended PHOBOS experiment.

  17. [Wounds caused by projectiles of pressure guns in children].

    PubMed

    Barreras-Salcedo, J I; Avila-Vergara, M A

    1993-05-01

    The present study is a survey to analyze the actual situation of the wounds produced by bibi-guns, concerning the damage produced, kind of surgical procedure, clinical evolution, and some general characteristics of the population on study. During a period of two years from May 1990 to May 1992 at the General Hospital of Culiacan, Sin. Six patients from the Pediatric Surgery Department with a diagnosis of wound produced by bibi-guns were studied. All patients required surgical treatment with general anesthesia. The average age of patients was 5.8 +/- 1.5 years, five male and one female; wounds were produced accidentally in four cases and two in a guns-game. The severity of the injury was evaluated, and in two cases their internal injury laid in danger the life of patient. No deaths occurred.

  18. Mission Connect Mild TBI Translational Research Consortium

    DTIC Science & Technology

    2010-08-31

    immunohistochemical; NP – not practical; PBI – pressure blast injury Blast- induced Brain Injury Model Characterization: David Ritzel, a widely recognized...test to our protocol, we were dependent upon each recruitment site’s policy regarding this test. This requirement eliminated all potential subjects at... induced brain injury (BIBI) that isolate the effects of blast to the brain rather than the body. The goal of this section of the project is to

  19. Defense Communications Agency Upper Level Protocol Test System Simple Mail Transfer Protocol Remote Driver Specification

    DTIC Science & Technology

    1988-05-01

    Inc.; Englewood Cliffs, NJ; 1978. Kernighan , B. W., and Pike, R.; The UNIX Programming Environment; Prentice-Hall, Inc.; Englewood Cliffs, NJ; 1984. B-I...B-i APPENDIX C EXAMPLES OF REMOTE DRIVER IMPLEMENTATION IN UNIX /C.............. C-i 1-1 SECTION 1 - SCOPE AND PURPOSE This manual describes the...in UNIX /C (Figure C-I). 3-2 Central I Driver Transport Connection DDN ) Network ( )__ __ _ _ Transport Connection Remote (background process) Driver

  20. Terahertz Quantum Cascade Structures Using Step Wells And Longitudinal Optical-Phonon Scattering

    DTIC Science & Technology

    2009-06-01

    8217 )(’ )( )()(’ )(’ )( )(’ )()(’ )( )()(’ )(’ )( n n nnnn n n nnnn n n nn n n nnnn n n nn n n B A BiAiBiAi m mAiAiAiAi m m BiBi m mBiBiBiAi m mBiAi B A αααααααα

  1. Color-flip solitons and the 3 + 1 QCD vacuum

    NASA Astrophysics Data System (ADS)

    Simonov, Yu. A.

    1984-02-01

    Nonperturbative configurations of the 3 + 1 gluodynamics in the continuous quenched hamiltonian formalism are identified in the tunneling between minima of the hamiltonian potential U - tr BiBi. The corresponding classical equations in imaginary (euclidean) time have finite-action solutions called color-flip solitons (cfs). Their contribution survives at large number of colors, indicating that cfs may be important in weak to intermediate coupling regimes.

  2. USSR Report, Political and Sociological Affairs

    DTIC Science & Technology

    1985-11-05

    impose alien views on people, and to sow the seeds of religious extremism. One effective way of instilling political consciousness in Soviet people... archeological excavations of three graves widely considered to be the burial sites of saints. The sites are those of Khoja Roshnai, Bibi Mushkul Kusha...Samarkand Gorkom, asso- ciates of the Institute of Archeology took up the task of exposing the false legends surrounding these sites and

  3. What's up, Billy Jo? Deaf children and bilingual-bicultural instruction in east-central Texas.

    PubMed

    Andrews, J F; Ferguson, C; Roberts, S; Hodges, P

    1997-03-01

    Seven deaf children attended a bilingual-bicultural (bi-bi) prekindergarten, kindergarten, and first grade from 1993 to 1996 in an east-central Texas public school. The children had diverse backgrounds (African American, Hispanic, White) and various intellectual, cognitive, and linguistic abilities. We detail the backgrounds of the seven children and their families and describe three bi-bi classrooms. We present standardized test scores on cognition (Bracken Test of Basic Concepts) and academic achievement (Stanford Achievement Test, 9th edition, and Woodcock-Johnson Psycho-Educational Battery). When, with one exception, the children completed first grade, they all tested at grade level. (The exception was a younger child who had only completed kindergarten but who nonetheless tested at the first-grade level). We interpret our findings in light of theories of first- and second-language acquisition and discuss the feasibility of establishing bi-bi programs in areas where no large Deaf community exists. We also note our plans to evaluate the seven children again, at the end of second grade in spring 1997.

  4. Using the Sediment Quality Triad to characterize baseline conditions in the Anacostia River, Washington, DC, USA.

    PubMed

    McGee, Beth L; Pinkney, Alfred E; Velinsky, David J; Ashley, Jeffrey T F; Fisher, Daniel J; Ferrington, Leonard C; Norberg-King, Teresa J

    2009-09-01

    The Sediment Quality Triad (SQT) consists of complementary measures of sediment chemistry, benthic community structure, and sediment toxicity. We applied the SQT at 20 stations in the tidal portion of the Anacostia River from Bladensburg, MD to Washington, DC to establish a baseline of conditions to evaluate the effects of management actions. Sediment toxicity was assessed using 10-day survival and growth tests with the freshwater amphipod, Hyalella azteca and the midge, Chironomus dilutus. Triplicate grabs were taken at each station for benthic community analysis and the Benthic Index of Biotic Integrity (B-IBI) was used to interpret the data. Only one station, #92, exhibited toxicity related to sediment contamination. Sediments from this station significantly inhibited growth of both test species, had the highest concentrations of contaminants, and had a degraded benthic community, indicated by a B-IBI of less than 3. Additional sediment from this station was tested and sediment toxicity identification evaluation (TIE) procedures tentatively characterized organic compounds as the cause of toxicity. Overall, forty percent of the stations were classified as degraded by the B-IBI. However, qualitative and quantitative comparisons with sediment quality benchmarks indicated no clear relationship between benthic community health and contaminant concentrations. This study provides a baseline for assessing the effectiveness of management actions in the Anacostia River.

  5. Situational Behavior Modeling

    DTIC Science & Technology

    2009-06-30

    Steinberg and C. L. Bowman. Revisions to the JDL Data Fusion Model. In D. L. Hall and J. Llinas (Eds.), Handbook of Multisensor Data Fusion, CRC Press...a mouse (Mickey) and a flower (we call it Tulip1), which are not involved in the chasing or watching situations but which might be involved in some...and relations are introduced. The classes include Person, Cat, Dog, Mouse, and Flower . These classes are subclasses of Individual. Third, we assert

  6. The Secretary of the Navy/Chief of Naval Operations Chair in Oceanographic Sciences

    DTIC Science & Technology

    2010-09-30

    2292. Lomas, M., D. Steinberg, T. Dickey, C. Carlson, N. Nelson, R. Condon, and N. Bates, 2009, Increased ocean carbon export in the Sargasso Sea ...predictive capabilities. These efforts bear on various naval operations in adverse weather and sea -state conditions. Mesoscale eddies, their...light across the air- sea interface and into and exiting the surface and upper ocean boundary layers. The first field experiment (relatively benign sea

  7. The Secretary of the Navy/Chief of Naval Operations Chair in Oceanographic Sciences

    DTIC Science & Technology

    2013-09-30

    Steinberg, D. K., Dickey, T., Carlson, C. A., Nelson, N. B., Condon, R. H., and Bates, N. R., 2009, Increased ocean carbon export in the Sargasso Sea is...studied the propagation of light across the air- sea interface and into and exiting the surface and upper ocean boundary layers. The first field...experiment (benign sea -state conditions) was conducted in the Santa Barbara Channel in September 2008 and the second field experiment (high sea -state

  8. Flying Blind: The Rise, Fall, and Possible Resurrection of Science Policy Advice in the United States

    DTIC Science & Technology

    2004-12-01

    Barry Sharpless George A. Silver * Richard E. Smalley * Robert M. Solow * Jack Steinberger * Joseph Stiglitz * Henry Taube * Daniel Tsui * Charles H...officio: Carl Kaysen Robert Solow Frank von Hippel Henry Kelly, Ivan Oelrich, Steven Aftergood, Benn H.Tannenbaum Occasional Paper No. 2 December 2004...about.htm. 116 http://www.tech-forum.org/. 117 Daniel S. Greenberg, Science, Money, and Politics (Chicago: The University of Chicago Press, 2001), p. 473

  9. Framing a Strategic Approach for Joint Officer Management

    DTIC Science & Technology

    2005-01-01

    the JDAL... 26 3.5. Marine Corps Starts, Stops, and Cumulative Change to the JD A L ......................................................... 27 3.6...interaction of Major Harvey Johnson, Lieutenant Colonel Charles Armentrout , Brad Loo, and Gwendolyn Rutherford from our sponsoring office and the input...J. Thie, Jennifer Kawata, Margaret C. Harrell, Clifford M. Graf II, and Paul Steinberg, Who Is Joint? Reevaluating the Joint Duty Assignment List

  10. A Graphical User Interface for the Low Cost Combat Direction System

    DTIC Science & Technology

    1991-09-16

    in surface non-combatant units. As a result of this survey, a number of areas not previously mentioned in Seveney/Steinberg were raised. The issues ...appear at the bont left side of the & crm D a. 4. DIspay iltdng FunctOs Like the Akrt parameters, the Dispa FRtr parameters ar selected in the Set...Display Defaults Analysis This category covers a wide range of required data input and system configuration issues . To keep the screen display manageable

  11. Content Effects in Mathematics Problem Solving. A Possible Source of Test Bias?

    DTIC Science & Technology

    1991-04-15

    Environmental Education , The Ohio State University. Becker, B.J. (1990) Item characteristics and gender differences on the SAT-M for mathematically able youths...Kantowski (Eds) Apolied Mathematical Problem Solvino, (pp. 25-35). Columbus, OH: ERIC Clearinghouse for Science, Mathematics, and Environmental ... Education , The Ohio State University. Tversky, A. (1977) Features of similarity. Psychological Review, 84, 327-352. 34 Wainer, H. & Steinberg, L.S. (1990

  12. Acute Lung Injury Following Smoke Inhalation: Predictive Value of Sputum Biomarkers and Time Course of Lung Inflammation

    DTIC Science & Technology

    2007-05-01

    potential confounders including age, asthma, COPD , percent of full thickness body surface burned, and fractures suffered. In an analysis of eight patients...macroglobulin and serum-derived IL-8 autoantibodies , may increase more than IL-8 in airway suction specimens, resulting in alterations in IL-8...JM, Steinberg KP et al. Anti-interleukin 8 autoantibody : interleukin 8 complexes in the acute respiratory distress syndrome. Relationship between

  13. Work-hardening and effective viscosity in solid beryllium

    SciTech Connect

    Steinberg, D.; Breithaupt, D.; Honodel, C.

    1985-06-01

    Results from Hopkinson split-bar, plate-impact, and cylinder deceleration experiments on beryllium are compared with hydrodynamic computer code simulations. By substantially increasing the beryllium work-hardening in the Steinberg-Guinan constitutive model, excellent agreement between the experiments and the calculations is achieved. A model to estimate effective viscosity is also proposed and the resultant calculations are in reasonable agreement with those derived from another model advanced by Asay, Chhabildas and Wise. 12 refs., 5 figs.

  14. The Strategic Consequences of Using Military Commissions to Adjudicate US Prisoners in the Global War on Terrorism

    DTIC Science & Technology

    2007-05-05

    April 2007 . 23 Neal K. Katyal and Laurence H. Tribe, “Waging War, Deciding Guilt; Trying the Military Tribunals,” Yale Law Journal, 111 (2002): 1259...94DB404482; Internet; accessed 22 April 2007 . 72 Ibid. 73 Ibid. 23 74 Thom Shanker and Jacques Steinberg , “THE STRUGGLE FOR IRAQ...College, Carlisle Barracks, PA 17013- USAWC CLASS OF 2007 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the

  15. A rate-dependent constitutive model for molybdenum

    NASA Astrophysics Data System (ADS)

    Steinberg, Daniel J.

    1994-07-01

    The Steinberg-Guinan-Lund rate-dependent constitutive model has been successfully applied to molybdenum. The model reproduces yield strength vs strain-rate and temperature data and also successfully simulates rate-dependent phenomena, such as shock-smearing, precursor decay, and precursor on reshock, as observed in one-dimensional gas-gun experiments. The spall strength of molybdenum was determined to be 1.5 GPa.

  16. Underwater Nondestructive Testing of Concrete: An Evaluation of Techniques.

    DTIC Science & Technology

    1986-02-01

    Mazanti. Atlanta. GA INSTITUTE OF MARINE SCIENCES Dir. Morehead City, NC: Dir. Port Aransas. TX; Library. Port Aransas. TX IOWA STATE UNIVERSITY CE Dept...storage battery and will operate for about 10 hours between charges. To fully recharge the battery from a completely discharged state requires about 16...Mgr ( Moss ). Camarillo. CA BERKELEY PW Engr Div (Harrison), Berkeley. CA BROOKHAVEN NATL LAB M. Steinberg, Upton, NY CALIF. DEPT OF FISH & GAME Marine

  17. Laser-Based Spectroscopic Studies of Propellant-Like Low-Pressure Flames

    DTIC Science & Technology

    1992-07-01

    Field Artillery School U.S. Army Laboratory Command ATTN: ATSF-CSI ATTN: AMSLC-DL Ft. Sill, OK 73503-5000 2800 Powder Mill Rd. Adeiphi, MD 20783-1145... Georgie Institute of Technology Jet Propulsion Laboratory School of Aerospace Engineering ATTN: L. Strand/MS 512/102 ATTN: E. Price 4800 Oak Grove...Engineering ATTN: A. Fontijn Troy, NY 12181 2 University of California, Santa Barbara Quantum Institute ATTN: K. Schofield M. Steinberg Santa Barbara

  18. EXPOSURE. A Newsletter for Ocean Technologists. Volume 9, Number 2,

    DTIC Science & Technology

    1981-05-01

    Applied Fluid Flow Measurement. Cheremisinoff 1979 Dekker Flowmeters. A.T.J. Hayward 1979 John Wiley & Sons (24.95) Manual on the Use of...Van Nostrand Cooling Techniques for Electronic Equipment D. Steinberg 1980 Wiley (27.50) Optoelectronics Applications Manual Hewlett-Packard 1981...Measurement & Technology. C. A. Vergers 1979 TAB BOOKS (6.95) (Basic treatment) Handbook of Noise Measurement. Arnold Peterson 8th ed. 1978 General

  19. Conventional Military Deterrence - Its Rise to Dominance and Its Future

    DTIC Science & Technology

    2007-11-02

    149; Timothy Garden, Can Deterrence Last: Peace Through a Nuclear Strategy (London: Buchan & Enright, 1984), Chapter One, pg. 1; and Gerald Steinberg...Strategy," U.S. Army War College Guide to Strategy, eds. Joseph R. Cerami and James F. Holcomb, Jr. (Carlisle Barracks, PA.: Strategic Studies...a New Direction, (Kentucky: The University of Kentucky Press, 2001), 17-18. 16 Jentleson, 246. 17 James Robinson, "Technology, Change and the

  20. Formal Mentoring in the U.S. Military: Research Evidence, Lingering Questions, and Recommendations

    DTIC Science & Technology

    2010-01-01

    Naval Command (Annapolis, Md.: Naval Institute Press, 2005). 6. Georgia T. Chao, “Formal Mentoring: Les- sons Learned from Past Practice...Military Medicine 166 (2001), pp. 27–31. 17. Baker, Hocevar, and Johnson, “Prevalence and Nature of Service Academy Mentoring.” 18. Alma G. Steinberg...Does Mentoring Foster Success?” 21. Georgia T. Chao, Pat M. Walz, and Philip D. Gardner, “Formal and Informal Mentorships: A Comparison on Mentoring

  1. DOD Product Support Business Case Analysis Guidebook

    DTIC Science & Technology

    2011-04-01

    operate ships and submarines as required to support FRP Ao. Controls. Budget exhibits, SNaP Report. Calculate Operations requirement, allocate fiscal ...Cargo Aircraft; Mike Tesi , 256-313-3745 10 Automatic Requirements Computation System Initial Provisioning (ARCSIP) CECOM; Ken Steinberg, LEO...Block III 256-313- 4988 PM Aviation Systems, PD Joint Cargo Aircraft Mike Tesi , 256- 313-3745 16 Computerized Optimization Model for

  2. Human Factors Issues for Interaction with Bio-Inspired Swarms

    DTIC Science & Technology

    2012-10-01

    subtle leaders of fish schools. Pheromone trails also suggest a way to support human interaction as has been explored to a limited extent... Human Factors issues for Interaction with Bio-Inspired Swarms Michael Lewis*, Michael Goodrich**, Katia Sycara+, Mark Steinberg++ * School of...Enabling a human to control such bio-inspired systems is a considerable challenge due to the limitations of each individual robot and the sheer

  3. [Comparison and application of biological indices of macroinvertebrates in river health assessment].

    PubMed

    Geng, Shi-Wei; Qu, Xiao-Dong; Zhang, Yuan; Lin, Kun-De

    2012-07-01

    The different biological indices usually result in different results in the river health assessment. It is imperative and valuable to identify the correlation among different indices and their applicability for assessing stream health. In this study, totally five biological indices were selected and compared in the investigation of macroinvertebrate communities in the Taizi river. The results showed significant correlations among the five indices. However, due to the difference in health rating criteria for each biological index, different results of health ratings were obtained when different indices were used. The responding sensitivities to disturbance caused by different types of human activities were studied for each index to determine their applicability in assessment of river health. The data indicated that the BI index had significant correlations with land use and dissolved oxygen and was a good indicator for these two types of disturbance. The FBI index could well reflect the acid and ammonia contamination of the investigated stream. Strong negative correlation was found between the ASPT index and several water quality parameters concerning oxygen consumption. The B-IBI index had a significant negative correlation with the total nitrogen concentration, being a good indicator for nitrogen contamination. Besides, the B-IBI index was also significantly correlated to disturbance caused by other types of human activities and can be used as an indicator for both land use and aquatic pollution. To be concluded, the BI index and ASPT index can be individually used to assess the land use of a riverine and the impact of hydrochemical index on the ecosystems, whereas the B-IBI index could be a suitable indicator for evaluating the stream health correlated with various human activities.

  4. Oxygen sensors for Heavy Liquid Metal coolants: Calibration and assessment of the minimum reading temperature

    NASA Astrophysics Data System (ADS)

    Bassini, S.; Antonelli, A.; Di Piazza, I.; Tarantino, M.

    2017-04-01

    Oxygen sensors for Heavy Liquid Metals (HLMs) such as lead and LBE (lead-bismuth eutectic) will be essential devices in future Lead Fast Reactor (LFR) and Accelerator Driven System (ADS). Potentiometric sensors based on solid electrolytes were developed in recent years to this purpose. Internal reference electrodes such as Pt-air and Bi/Bi2O3 liquid metal/metal-oxide are among the most used but they both have a weak point: Pt-air sensor has a high minimum reading temperature around 400 °C whereas Bi/Bi2O3 suffers from internal stresses induced by Bi volume variations with temperature, which may lead to the sensor failure in the long-term. The present work describes the performance of standard Pt-air and Bi/Bi2O3 sensors and compares them with recent Cu/Cu2O sensor. Sensors with Yttria Partially Stabilized Zirconia (YPSZ) electrolyte were calibrated in oxygen-saturated HLM between 160 and 550 °C and the electric potential compared to the theoretical one to define the accuracy and the minimum reading temperature. Standard Pt-air sensor were also tested using Yttria Totally Stabilized Zirconia (YTSZ) to assess the effect of a different electrolyte on the minimum reading temperature. The performance of Pt-air and Cu/Cu2O sensors with YPSZ electrolyte were then tested together in low-oxygen HLM between 200 and 450 °C. The results showed that Pt-air, Bi/Bi2O3 and Cu/Cu2O sensors with YPSZ measured oxygen in HLMs down to 400 °C, 290 °C and 200 °C respectively. When the YTSZ electrolyte was used in place of the YPSZ, the Pt-air sensor measured correctly down to at least 350 °C thanks to the superior ionic conductivity of the YTSZ. When Cu/Cu2O and Pt-air sensors were tested together in the same low-oxygen HLM between 200 and 450 °C, Cu/Cu2O sensor worked predictably in the whole temperature range whereas Pt-air sensor exhibited a correct output only above 400 °C.

  5. Validation Summary Report IBM 360/370 FORTRAN IV H.

    DTIC Science & Technology

    1977-05-17

    S S - —. &— —- ~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~ ~~~~~~~ ~~~‘~L ._~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~ S S - ~~~~~~~~~ S BIBI ~OGRA~ H

  6. Effect of chain length of alcohol on the lipase-catalyzed esterification of propionic acid in supercritical carbon dioxide.

    PubMed

    Varma, Mahesh N; Madras, Giridhar

    2010-04-01

    The esterification of propionic acid was investigated using three different alcohols, namely, isopropyl alcohol, isobutyl alcohol, and isoamyl alcohol. The variation of conversion with time for the synthesis of isoamyl propionate was investigated in the presence of five enzymes. Novozym 435 showed the highest activity, and this was used as the enzyme for investigating the various parameters that influence the esterification reaction. The Ping-Pong Bi-Bi model with inhibition by both acid and alcohol was used to model the experimental data and determine the kinetics of the esterification reaction.

  7. Applying Benthic Index of Biotic Integrity in a soft bottom ecosystem in North of the Persian Gulf.

    PubMed

    Doustshenas, B; Savari, A; Nabavi, S M B; Kochanian, P; Sadrinasab, M

    2009-06-15

    In this study, the Chesapeake Bay Benthic Index of Biotic Integrity (B-IBI) was selected in an attempt to describe ecological health of soft bottom channels (Khowr-e Musa) in North of the Persian Gulf. Most of study area was found to be in degraded or severely degraded conditions. B-IBI scores were ranged between 1 and 3.86. Comparison ofmacrobenthos abundance and organic content between two developmental periods showed significant difference (p < 0.05). After the establishment and development of petrochemical industries, the abundance of macrofauna decreased (809 to 239 individuals m(-2)) and organic content increased leading to organic enrichment (15.3 to 22.4%). Three new sources of organic matter were found to be important namely industrial waste, sewage and mangrove litter. After 1999 about 6 millions Avicennia marina tree were planted near petrochemical zone in the area. Study area changed rapidly in the last decade and region is under severely anthropogenic impacts. The present study showed that Khowr-e Musa is under both natural stress and anthropogenic impacts and two main impacts could be attributed to the organic enrichment and to the dredging. Choice of suitable management plans and metric controls could help to the salvage of the largest tidal channel complex in Persian Gulf.

  8. Effects of urbanization on benthic macroinvertebrate assemblages in contrasting environmental settings: Boston, Massachusetts; Birmingham, Alabama; and Salt Lake City, Utah

    USGS Publications Warehouse

    Cuffney, T.F.; Zappia, H.; Giddings, E.M.P.; Coles, J.F.

    2005-01-01

    Responses of invertebrate assemblages along gradients of urban intensity were examined in three metropolitan areas with contrasting climates and topography (Boston, Massachusetts; Birmingham, Alabama; Salt Lake City, Utah). Urban gradients were defined using an urban intensity index (UII) derived from basin-scale population, infrastructure, land-use, land-cover, and socioeconomic characteristics. Responses based on assemblage metrics, indices of biotic integrity (B-IBI), and ordinations were readily detected in all three urban areas and many responses could be accurately predicted simply using regional UIIs. Responses to UII were linear and did not indicate any initial resistance to urbanization. Richness metrics were better indicators of urbanization than were density metrics. Metrics that were good indicators were specific to each study except for a richness-based tolerance metric (TOLr) and one B-IBI. Tolerances to urbanization were derived for 205 taxa. These tolerances differed among studies and with published tolerance values, but provided similar characterizations of site conditions. Basin-scale land-use changes were the most important variables for explaining invertebrate responses to urbanization. Some chemical and instream physical habitat variables were important in individual studies, but not among studies. Optimizing the study design to detect basin-scale effects may have reduced the ability to detect local-scale effects. ?? 2005 by the American Fisheries Society.

  9. Characterization of human platelet UDPglucose-collagen glucosyltransferase using a new rapid assay.

    PubMed

    Smith, D F; Kosow, D P; Wu, C; Jamieson, G A

    1977-08-11

    A rapid and specific assay has been developed for UDPglucose-collagen glucosyltransferase (UDPglucose: 5-hydroxylysine-collagen glucosyltransferase, EC 2.4.1.66) using galactosylhydroxylysine (Gal-Hyl) as acceptor. Studies with intact human platelets and isolated plasma membranes indicated that about 5--10% of the total activity was surface bound and the rest was of cytoplasmic origin. The two forms of the enzyme had similar broad pH optima (6.5--8.0), Km values for UDPglucose (5 muM) and Gal-Hyl (approx. 4 mM) and for optimal manganese concentrations (25 mM). The soluble form of the enzyme was purified 80-fold. The reaction mechanism was determined as being rapid equilibrium random BiBi + dead end complex or ordered BiBi with UDPglucose being the first substrate to bind. Using Gal-Hyl bound in purified alpha 1 chain of chick skin collagen, a Km value three orders of magnitude less (2 muM) was found than for free Gal-Hyl and the manganese requirement decreased to 2 mM. These results suggest that the binding to the enzyme of Gal-Hyl in the collagen molecule is enhanced by the presence of the protein portion so that the enzyme may be capable of recognizing not only the carbohydrate side chains but also the primary structure of collagen.

  10. Inertial fusion features in degenerate plasmas

    NASA Astrophysics Data System (ADS)

    León, Pablo T.; Eliezer, Shalom; Piera, Mireia; Martínez-Val, José M.

    2005-04-01

    Very high plasma densities can be obtained at the end of the implosion phase in inertial fusion targets, particularly in the so-called fast-ignition scheme (Tabak et al., 1994; Mulser & Bauer, 2004), where a central hot spark is not needed at all. By properly tailoring the fuel compression stage, degenerate states can be reached (Azechi et al., 1991; Nakai et al., 1991; McCory, 1998). In that case, most of the relevant energy transfer mechanisms involving electrons are affected (Honrubia & Tikhonchuk, 2004; Bibi & Matte, 2004; Bibi et al., 2004). For instance, bremsstrahlung emission is highly suppressed (Eliezer et al., 2003). In fact, a low ignition-temperature regime appears at very high plasma densities, due to radiation leakage reduction (León et al., 2001). Stopping power and ion-electron coulomb collisions are also changed in this case, which are important mechanisms to trigger ignition by the incoming fast jet, and to launch the fusion wave from the igniting region into the colder, degenerate plasma. All these points are reviewed in this paper. Although degenerate states would not be easy to obtain by target implosion, they present a very interesting upper limit that deserves more attention in order to complete the understanding on the different domains for inertial confinement fusion.

  11. Assessing ecological integrity for impaired waters decisions in Chesapeake Bay, USA.

    PubMed

    Llansó, Roberto J; Dauer, Daniel M; Vølstad, Jon H

    2009-01-01

    To meet the requirements of the Clean Water Act, the States of Maryland and Virginia are using benthic biological criteria for identifying impaired waters in Chesapeake Bay and reporting their overall condition. The Chesapeake Bay benthic index of biotic integrity (B-IBI) is the basis for these biological criteria. Working together with the states and the US Environmental Protection Agency, we developed a method for impairment decisions based on the B-IBI. The impaired waters decision approach combines multiple benthic habitat-dependent indices in a Bay segment (equivalent to water bodies in the European Water Framework Directive) with a statistical test of impairment. The method takes into consideration uncertainty in reference conditions, sampling variability, multiple habitats, and sample size. We applied this method to 1430 probability-based benthic samples in 85 Chesapeake Bay segments. Twenty-two segments were considered impaired for benthic community condition. The final decision for each segment considers benthic condition in combination with key stressors such as dissolved oxygen and toxic contaminants.

  12. Integrated assessment of river health based on water quality, aquatic life and physical habitat.

    PubMed

    Meng, Wei; Zhang, Nan; Zhang, Yuan; Zheng, Binghui

    2009-01-01

    The health conditions of Liao River were assessed using 25 sampling sites in April 2005, with water quality index, biotic index and physical habitat quality index. Based on the method of cluster analysis (CA) for water quality indices, it revealed that heavily polluted sites of Liao River are located at estuary and mainstream. The aquatic species surveyed were attached algae and benthic invertebrates. The result showed that the diversity and biomass of attached algae and benthic index of biotic integrity (B-IBI) were degrading as the chemical and physical quality of water bodies deteriorating. Physiochemical parameters, BOD5, COD(Cr), TN, TP, NH3-N, DO, petroleum hydrocarbon and conductivity, were statistically analyzed with principal component analysis and correlation analysis. The statistical results were incorporated into the integrated assessing water quality index, combining fecal coliform count, attached algae diversity, B-IBI and physical habitat quality score. A comprehensive integrated assessing system of river ecological health was established. Based on the systimetic assessment, the assessed sites are categorized into 9 "healthy" and "sub-healthy" sites and 8 "sub-sick" and "sick" sites.

  13. A Within-Subject Comparison of Bimodal Hearing, Bilateral Cochlear Implantation, and Bilateral Cochlear Implantation With Bilateral Hearing Preservation: High-Performing Patients.

    PubMed

    Gifford, René H; Driscoll, Colin L W; Davis, Timothy J; Fiebig, Pam; Micco, Alan; Dorman, Michael F

    2015-09-01

    To compare speech understanding with bimodal hearing and bilateral cochlear implants (CIs). Within-subjects, repeated-measures. Speech understanding was assessed in the following conditions: unilateral hearing aid (HA) in the non-implanted ear, unilateral CI, bimodal (CI + HA), and bilateral CI. In addition, three participants had bilateral hearing preservation and were also tested with bilateral CIs and bilateral HAs (BiBi). Tertiary academic CI center. Eight adult sequential bilateral recipients who, despite achieving incredibly high performance with the first CI, self-selected for bilateral cochlear implantation. Bilateral cochlear implantation. Speech understanding for the adult minimum speech test battery as well as sentences in semidiffuse noise using the R-SPACE system. Bilateral CIs afforded significant individual improvement in a complex listening environment even for individuals demonstrating near perfect sentence scores with both the first CI alone as well as the bimodal condition. The 3 BiBi participants demonstrated additional significant benefit over the bilateral CI condition-presumably because of the availability of interaural time difference cues. These data suggest that, for noisy environments, adding a second implant can significantly improve speech understanding-even for high-performing unilateral CI with bimodal hearing. In diffuse noise conditions, bilateral acoustic hearing can yield even greater benefits beyond that offered by bilateral implantation.

  14. A within-subjects comparison of bimodal hearing, bilateral cochlear implantation, and bilateral cochlear implantation with bilateral hearing preservation: High-performing patients

    PubMed Central

    Gifford, René H.; Driscoll, Colin L. W.; Davis, Timothy J.; Fiebig, Pam; Micco, Alan; Dorman, Michael F.

    2016-01-01

    A comparison of bimodal hearing and bilateral cochlear implants (CIs) was completed using a within-subjects, repeated-measures study for eight adult sequential recipients who despite achieving incredibly high performance with the first CI, self-selected for bilateral implantation. Speech understanding was assessed with the minimum speech test battery (MSTB) as well as sentences in semi-diffuse noise using the R-SPACE™ system. Conditions included unilateral hearing aid (HA) in the non-implanted ear, unilateral CI, bimodal (CI+HA), and bilateral CI. Additionally, three participants had bilateral hearing preservation and were also tested with bilateral CIs and bilateral HAs (BiBi). All testing was completed in the bimodal hearing configuration and repeated at least six months following activation of the second CI. Bilateral CIs afforded significant individual improvement in a complex listening environment even for individuals demonstrating near perfect sentence scores with both the 1st CI alone as well as the bimodal condition. The 3 BiBi participants demonstrated additional significant benefit over the bilateral CI condition—presumably due to the availability of interaural time difference cues. These data suggest that for noisy environments, adding a second implant can significantly improve speech understanding—even for high performing unilateral CI with bimodal hearing. In diffuse noise conditions, bilateral acoustic hearing can yield even greater benefit beyond that offered by bilateral implantation. PMID:26164443

  15. Sensitivity analysis of seismic hazard for Western Liguria (North Western Italy): A first attempt towards the understanding and quantification of hazard uncertainty

    NASA Astrophysics Data System (ADS)

    Barani, Simone; Spallarossa, Daniele; Bazzurro, Paolo; Eva, Claudio

    2007-05-01

    The use of logic trees in probabilistic seismic hazard analyses often involves a large number of branches that reflect the uncertainty in the selection of different models and in the selection of the parameter values of each model. The sensitivity analysis, as proposed by Rabinowitz and Steinberg [Rabinowitz, N., Steinberg, D.M., 1991. Seismic hazard sensitivity analysis: a multi-parameter approach. Bull. Seismol. Soc. Am. 81, 796-817], is an efficient tool that allows the construction of logic trees focusing attention on the parameters that have greater impact on the hazard. In this paper the sensitivity analysis is performed in order to identify the parameters that have the largest influence on the Western Liguria (North Western Italy) seismic hazard. The analysis is conducted for six strategic sites following the multi-parameter approach developed by Rabinowitz and Steinberg [Rabinowitz, N., Steinberg, D.M., 1991. Seismic hazard sensitivity analysis: a multi-parameter approach. Bull. Seismol. Soc. Am. 81, 796-817] and accounts for both mean hazard values and hazard values corresponding to different percentiles (e.g., 16%-ile and 84%-ile). The results are assessed in terms of the expected PGA with a 10% probability of exceedance in 50 years for rock conditions and account for both the contribution from specific source zones using the Cornell approach [Cornell, C.A., 1968. Engineering seismic risk analysis. Bull. Seismol. Soc. Am. 58, 1583-1606] and the spatially smoothed seismicity [Frankel, A., 1995. Mapping seismic hazard in the Central and Eastern United States. Seismol. Res. Lett. 66, 8-21]. The influence of different procedures for calculating seismic hazard, seismic catalogues (epicentral parameters), source zone models, frequency-magnitude parameters, maximum earthquake magnitude values and attenuation relationships is considered. As a result, the sensitivity analysis allows us to identify the parameters with higher influence on the hazard. Only these

  16. Kernel weights optimization for error diffusion halftoning method

    NASA Astrophysics Data System (ADS)

    Fedoseev, Victor

    2015-02-01

    This paper describes a study to find the best error diffusion kernel for digital halftoning under various restrictions on the number of non-zero kernel coefficients and their set of values. As an objective measure of quality, WSNR was used. The problem of multidimensional optimization was solved numerically using several well-known algorithms: Nelder- Mead, BFGS, and others. The study found a kernel function that provides a quality gain of about 5% in comparison with the best of the commonly used kernel introduced by Floyd and Steinberg. Other kernels obtained allow to significantly reduce the computational complexity of the halftoning process without reducing its quality.

  17. From the Proton Synchroton to the Large Hadron Collider - 50 Years of Nobel Memories in High-Energy Physics

    ScienceCinema

    None

    2016-07-12

    The seminars will be held in the Main Auditorium with transmission to : Council Chamber, IT Auditorium, Prévessin BE Auditorium , Kjell Johnssen Auditorium in Building 30, Room 40-S2-A01, and via webcast. Confirmed Speakers include: Prof. Jack Steinberger, Dr. Guenther Plass, Prof. Emilio Picasso, Dr. Steve Myers, Prof. Carlo Rubbia, Prof. Burton Richter, Dr. Lyndon Evans, Prof. Rolf-Dieter Heuer, Prof. Leon Lederman, Prof. Jim Cronin, Prof. Sheldon Glashow, Prof. Jerome Friedman, Prof. Frank Wilczek, Prof. Martinus Veltman, Prof. Gerardus 't Hooft, Prof. David Gross, Prof. Samuel Ting, Prof. Steven Weinberg (via teleconference) --- Contact: Directorate.Office@cern.ch

  18. Space Storms and Space Weather Hazards

    DTIC Science & Technology

    2007-11-02

    203, 257. Burlaga, L.F., Fitzenreiter, R., Lepping, R., Ogilvie, K., Szabo, A., Lazarus, A., Steinberg, J., Gloeckler, G., Howard, R., Michels , D...Jr., N.R., Michels , D.J., Howard, R.A., Koomen, M.J., Schwenn, R. and Rosenbauer, H., 1982. A magnetic cloud and a coronal mass ejection. Geophys...601. Dere, K.P., Brueckner, G.E., Howard, R.A., Michels , D.J. and Delaboudiniere, J.P., (1999), LASCO and EIT observations of helical structure in

  19. COMMITTEES: SQM2004 Organising and International Advisory Committees

    NASA Astrophysics Data System (ADS)

    2005-06-01

    Organising Committee Jean Cleymans (Chairman) Zeblon Vilakazi Roger Fearick Peter Steinberg Rory Adams Bruce Becker Sarah Blyth Gareth de Vaux Heather Gray Mark Horner Nawahl Razak Artur Szostak Spencer Wheaton International Advisory Committee Federico Antinori Tim Hallman John Harris Tetsuo Hatsuda Ulrich Heinz Huan Z Huang Sonja Kabana Volker Koch Rob Lacey Jes Madsen Yasuo Miake Maurizio Morando Berndt Mueller Grazyna Odyniec Helmut Oeschler Apostolos Panagiotou Josef Pochodzalla Johann Rafelski Karel Safarik Jack Sandweiss Jürgen Schaffner-Bielich Georges Stephans Horst Stoecker Herbert Stroebele Thomas Ullrich Orlando Villalobos-Baillie Bill Zajc Joseph Zimanyi

  20. Differences in Conformational Stability Between Native and Phosphorylated Acetycholinesterase as Evidenced by a Monoclonal Antibody

    DTIC Science & Technology

    1990-03-13

    nonreactivatable) and nonaged OP- p- nitrophenyl phosphate [(C2H50)2P(O)(O-p-N0 2C6H4), Cht conjugates (Steinberg et al., 1988). A second method of paraoxon], DFP...Goasdoue I Abbreviations: AChE, acetyle 0inesteras FDS fetal bovine bmain; BChE. butyrylcholinesterase; OP, or phosphate ; mAb, mmoclonal antibody; DFP...approximately I AM in 50 mM phosphate , pH 8.0) with Purified AChE from bovine erythrocytes (G2) and human stirring at room temperature. Decrease in

  1. Zinc Finger Transcription Factors as Novel Switches to Modulate Metastatic Progression of Breast Tumors

    DTIC Science & Technology

    2007-05-01

    Biochemistry, Université de Montréal (Canada) 1995-1999 - Ph.D. Program, Biochemistry, Université de Montréal with Robert Cedergren 1999-2003...work) Blancafort, P., Ferbeyre, G., Sariol, C., and Cedergren , R. Pol I-driven integrative expression vectors for yeast. Journal of Biotechnology...1997;56:41-7 Blancafort, P., Klinck, R., Steinberg, S., Scott, J.K. and Cedergren , R. The recognition of a non-canonical base pair by a zinc finger protein

  2. Honors

    NASA Astrophysics Data System (ADS)

    2012-02-01

    James Yoder, vice president for academic programs and dean at the Woods Hole Oceanographic Institution, Woods Hole, Mass., has been selected as a fellow of the Oceanography Society (TOS) “for his innovative and visionary application of satellite ocean color technologies to interdisciplinary oceanography and his extraordinary service to oceanography.” TOS also has three new councilors. Blanche Meeson of NASA Goddard Space Flight Center, Greenbelt, Md., is TOS's education councilor; Janet Sprintall, Scripps Institution of Oceanography, La Jolla, Calif., is TOS's councilor for physical biology; and Deborah Steinberg, Virginia Institute of Marine Sciences, Gloucester Point, is biological oceanography councilor.

  3. Noisy Nonlinear Dynamics of Vesicles in Flow

    NASA Astrophysics Data System (ADS)

    Abreu, David; Seifert, Udo

    2013-06-01

    We present a model for the dynamics of fluid vesicles in linear flow which consistently includes thermal fluctuations and nonlinear coupling between different modes. At the transition between tank treading and tumbling, we predict a trembling motion which is at odds with the known deterministic motions and for which thermal noise is strongly amplified. In particular, highly asymmetric shapes are observed even though the deterministic flow only allows for axisymmetric ones. Our results explain quantitatively recent experimental observations [Levant and Steinberg, Phys. Rev. Lett. 109, 268103 (2012)PRLTAO0031-9007].

  4. Design Optimization of Systems Governed by Partial Differential Equations. Phase 1

    DTIC Science & Technology

    1989-03-01

    Arbitrary Two- calculated EF = 1.19 for this case. Dimensional Bodies," J. Computational Physics, Vol. 15, No. 3, July 1974, pp. 299-319. 2. Thompson , J . F ., Thames...686. 4. Roacne, P. j., "The LAD, NOS, and Split NOS 20. Thompson , J . F ., "Elliptic Grid Generation," Methods for the Steady State Navier-Stokes in Ref...13. Thompson , J . F ., ed., Numerical Grid Generation June 1983. Elsevier Science Publishing Co., New York. 28. Roache, P. J., Steinberg, S., Happ, H. J

  5. Why Promotable Female Officers Leave the Army

    DTIC Science & Technology

    1993-07-01

    34AD-A268 946 Study l Report 93-04 Why Promotable Female Officers Leave the Army Alma G. Steinberg, Beverly C. Harris, and Jacquelyn Scarville U.S...DATE 3 REPORT TYPE AND DATES COVERED I 1993, July Final Jul 92 - Oct 92 4 TITLE AND SUBTITLE S. FUNDING NUMBERS ;T,’hy Promotable Female Officers Leave...13. ABSTRACT (Maximuhm 200 words) This paper presents the findings of a study designed to identify the reasons female Captains who were eligible for

  6. The data acquisition system for ALEPH

    SciTech Connect

    Videau, I.

    1985-08-01

    The ALEPH Collaboration is formed by 27 institutes from nine countries plus CERN and counts about 300 physicists and engineers. Its spokesman is Jack Steinberger (CERN). The ALEPH Detector is being built by the collaboration now, in order to operate at LEP beginning of 1989. LEP is the Large Electron Positron Collider built at CERN. Its initial energy will be of 90GeV (Phase I) and its nominal luminosity 10/sup 32/cm/sup -1/s/sup -1/. It is foreseen to increase the energy of the machine up to about 200 GeV during Phase II.

  7. From the Proton Synchroton to the Large Hadron Collider - 50 Years of Nobel Memories in High-Energy Physics

    SciTech Connect

    2009-12-07

    The seminars will be held in the Main Auditorium with transmission to : Council Chamber, IT Auditorium, Prévessin BE Auditorium , Kjell Johnssen Auditorium in Building 30, Room 40-S2-A01, and via webcast. Confirmed Speakers include: Prof. Jack Steinberger, Dr. Guenther Plass, Prof. Emilio Picasso, Dr. Steve Myers, Prof. Carlo Rubbia, Prof. Burton Richter, Dr. Lyndon Evans, Prof. Rolf-Dieter Heuer, Prof. Leon Lederman, Prof. Jim Cronin, Prof. Sheldon Glashow, Prof. Jerome Friedman, Prof. Frank Wilczek, Prof. Martinus Veltman, Prof. Gerardus 't Hooft, Prof. David Gross, Prof. Samuel Ting, Prof. Steven Weinberg (via teleconference) --- Contact: Directorate.Office@cern.ch

  8. Streamflow, water-quality, and biological data for three tributaries to Lake Houston near Houston, Texas, 2002-04

    USGS Publications Warehouse

    East, Jeffery W.; Sneck-Fahrer, Debra A.

    2005-01-01

    -insect taxa (17) were collected at site on Caney Creek near New Caney. The benthic-macroinvertebrate index of biotic integrity (B-IBI) scores (averages of samples) for the three upstream Lake Creek sites indicate intermediate aquatic life use, and the B-IBI score for the most downstream site indicates high aquatic life use. B-IBI scores for the Peach Creek sites, in downstream order, are exceptional and high; and scores for the Caney Creek sites, in downstream order, are high and intermediate.

  9. Streamflow, water-quality, and biological data for three tributaries to Lake Houston near Houston, Texas, 2002-04

    USGS Publications Warehouse

    East, Jeffery W.; Sneck-Fahrer, Debra A.

    2005-01-01

    -insect taxa (17) were collected at site on Caney Creek near New Caney. The benthic-macroinvertebrate index of biotic integrity (B-IBI) scores (averages of samples) for the three upstream Lake Creek sites indicate intermediate aquatic life use, and the B-IBI score for the most downstream site indicates high aquatic life use. B-IBI scores for the Peach Creek sites, in downstream order, are exceptional and high; and scores for the Caney Creek sites, in downstream order, are high and intermediate.

  10. Change of shear modulus and yield stress with pressure and temperature

    NASA Astrophysics Data System (ADS)

    Partom, Yehuda

    2017-01-01

    It is well known that the shear modulus (G) and the yield stress (Y) of metals increase with pressure (P) and decrease with temperature (T). Steinberg, in his popular compendium of dynamic material properties, assumes for Y/Y0(P,T)=G/G0(P,T) linear relations based on derivatives determined experimentally at ambient conditions. But recent tests with high pressure dynamic loadings of certain metals obtained results that generally deviate from Steinberg's predictions. Here we use a different approach to estimate G/G0(P,T). As a first approximation we let G/G0=K/K0, where K is the isentropic bulk modulus. With this assumption we compute the longitudinal sound speed of tantalum along its principal Hugoniot and compare to recent measurements. There is a very slight disagreement, which we can correct by assuming (second approximation) that Poisson ratio decreases slightly with pressure and increases slightly with temperature. As K=ρc2 is always available in a hydrocode run from the equation of state, so are therefore also G/G0 and Y/Y0.

  11. Hyperbaric oxygen therapy in the treatment of osteonecrosis of the femoral head: a review of the current literature.

    PubMed

    Uzun, Gunalp; Mutluoglu, Mesut; Ersen, Omer; Yildiz, Senol

    2016-01-01

    To review the current literature on the use of hyperbaric oxygen (HBO₂) therapy in the treatment of osteonecrosis of the femoral head (ONFH). We searched PubMed, Directory of Open Access Journals (DOAJ), EMBASE, Web of Science, Academic Search Complete, CINAHL and MEDLINE through April 2015. We hand-searched relevant textbooks, conference proceedings and the reference lists of review articles and clinical studies Randomized controlled trials (RCT) and observational studies (cohort study, case-control study, case series) that reported the outcome of patients who received HBO₂therapy for ONFH were included. Only English-language articles were included. Study quality was not used as an exclusion criterion. Two authors independently assessed trials for inclusion, extracted data and presented to other authors. Disagreements were resolved by consensus. We identified eight clinical studies; two randomized controlled trials (RCTs); one historically controlled study; and five case series. The majority of the studies were small-scale, heterogeneous and methodologically weak. In four of the studies HBO₂therapy was combined with other treatment modalities, making it impossible to draw firm conclusions on the specific effects of HBO₂therapy. Hip survivorship in studies wherein HBO₂therapy was used alone was 95.5% in Steinberg Stage I lesions, 89% in Steinberg Stage II lesions and 100% in Ficat Stage II lesions. There is a room for HBO₂therapy in the management ONFH. Further RCTs, however, are required to better elucidate the role of HBO₂therapy in the treatment of ONFH.

  12. Treatment of osteonecrosis of the femoral head by free vascularized fibular grafting: an analysis of surgical outcome and patient health status

    PubMed Central

    Louie, Brian E.; McKee, Michael D.; Richards, Robin R.; Mahoney, James L.; Waddell, James P.; Beaton, Dorcas E.; Schemitsch, Emil H.; Yoo, Daniel J.

    1999-01-01

    Objective To evaluate the limb-specific outcome and general health status of patients with osteonecrosis of the femoral head treated with vascularized fibular grafting. Design A retrospective review. Setting A single tertiary care centre. Patients Fifty-five consecutive patients with osteonecrosis of the femoral head who underwent fibular grafting (8 bilaterally). Intervention Vascularized fibular grafting. Outcome measures Limb-specific scores (Harris Hip Score, St. Michael’s Hospital Hip Score), general health status (Nottingham Health Profile, SF-36 health status survey) and radiographic outcome measures (Steinberg stage). Results Patients were young (mean age 34 years, range from 18 to 52 years) and 80% had advanced osteonecrosis (Steinberg stages IV and V). Fifty-nine hips were followed up for an average of 50 months (range from 24 to 117 months) after vascularized fibular grafting. Sixteen hips (27%) were converted to total hip arthroplasty (THA). To date, 73% of hips treated with vascularized fibular grafting have required no further surgery. Preoperative and postoperative Harris Hip Scores were 57.3 and 83.6 respectively (p < 0.001). As measured by patient-oriented health status questionnaires (SF-36, Nottingham Health Profile) and compared with population controls, patients had normal mental health scores and only slight decreases in physical component scores. Conclusions Free vascularized fibular grafting for osteonecrosis of the femoral head provides satisfactory pain relief, functional improvement and general health status and halts the progression of symptomatic disease. PMID:10459327

  13. The rarefaction wave propagation in transparent windows

    NASA Astrophysics Data System (ADS)

    Glam, B.; Porat, E.; Horovitz, Y.; Yosef-Hai, A.

    2017-01-01

    The radial (lateral) rarefaction wave velocity of polymethyl methacrylate (PMMA) and Lithium Fluoride (LiF) windows were studied by plate impact experiments that were carried out at Soreq NRC up to a pressure of 146 kbar in the PMMA and 334 kbar in the LiF. The windows were glued to Lead targets that were impacted by a copper impactor. The VISAR measurement was done in the window interface with the target. This information was utilized to identify the radial rarefaction arrival time at the center of different diameter windows after the shock event, and served as a measurement to the radial wave velocity in the shocked material. It was found that for both windows, LiF or PMMA, the measured radial wave velocity increases with the pressure. Furthermore, this velocity is significantly higher compared to the expected longitudinal sound velocity at the same pressure, calculated by the Steinberg EOS in the PMMA and by ab initio calculation in the LiF. Here we present the experimental results and a comparison with analytical calculation of the sound velocity using the Steinberg EOS.

  14. A syllabus for Jewish medical ethics in the context of general bioethics.

    PubMed

    Gesundheit, Benjamin; Shaham, Dorith

    2008-05-01

    Since the beginning of medical history, ethics has interested medical practitioners. The subject has become particularly important in recent years due to the huge advancements in medicine and medical technology and has elicited much public interest. While international ethical principles and guidelines have been established, classical Jewish tradition has always placed great emphasis on bioethics. Prof. Avraham Steinberg's monumental Encyclopedia of Jewish Medical Ethics presents the subject comprehensively and in depth. We propose a bioethics syllabus, to be integrated into the medical curriculum in three stages: i) preclinical - covering basic ethical concepts and principles, relevant history, and ethical codes; ii) clinical - covering bioethical topics relating to the human life cycle; iii) prior to students' final examinations and further specialization - covering bioethical topics relating to their personal interests. Steinberg's Encyclopedia is an ideal basis for the development of a professional course, including Jewish traditional aspects. Such a course would provide future physicians with a varied cultural and intercultural background, help shape their image, and improve the quality of medical care.

  15. Bidirectional Associations between Bedtime Parenting and Infant Sleep: Parenting Quality, Parenting Practices, and their Interaction

    PubMed Central

    Philbrook, Lauren E.; Teti, Douglas M.

    2016-01-01

    In keeping with transactional conceptualizations of infant sleep development (Sadeh et al., 2010), the present study examined longitudinal, bidirectional linkages between bedtime parenting (direct observations of parenting practices and quality) and infant sleep across the first six months postpartum. In doing so, we also drew from Darling and Steinberg's (1993) conceptual model to examine parenting quality as a moderator of linkages between specific bedtime practices and infant sleep. Multilevel model analyses revealed that the strongest increases in infant nighttime sleep across the first six months occurred among infants of mothers who engaged in low levels of nursing at bedtime. Within-person linkages between mothers' emotional availability (EA) at bedtime, infant distress, and infant sleep were found, such that at time points when mothers were more emotionally available, infants were less distressed and slept more throughout the night. Several moderating effects of maternal EA on linkages between parenting practices and infant sleep were obtained that were consistent with predictions from Darling and Steinberg (1993). Higher maternal EA in combination with less close contact at bedtime was associated with more infant sleep across the night on average, and higher EA in combination with fewer arousing bedtime activities predicted more rapid increases in infant sleep with age. Finally, there was evidence of infant-driven effects, as higher infant nighttime distress predicted lower EA at subsequent time points. Results showcased the complex, reciprocal interplay between parents and infants in the development of infant sleep patterns and parenting behavior during the first six months postpartum. PMID:27010601

  16. Too close and too rigid: applying the Circumplex Model of Family Systems to first-generation family firms.

    PubMed

    Michael-Tsabari, Nava; Lavee, Yoav

    2012-06-01

    Despite growing research interest in family businesses, little is known about the characteristics of the families engaging in them. The present paper uses Olson's (Journal of Psychotherapy & the Family, 1988, 4(12), 7-49; Journal of Family Therapy, 2000, 22, 144-167) Circumplex Model of Marital and Family Systems to look at first-generation family firms. We describe existing typologies of family businesses and discuss similarities between the characteristics of first-generation family firms and the rigidly enmeshed family type described in the Circumplex Model. The Steinberg family business (Gibbon & Hadekel (1990) Steinberg: The breakup of a family empire. ON, Canada: MacMillan) serves to illustrate the difficulties of rigidly enmeshed first-generation family firms. Implications for understanding troubled family businesses are discussed together with guidelines for the assessment of a family business in crisis and for intervention: enhancing open communication; allowing for more flexible leadership style, roles, and rules; and maintaining a balance between togetherness and separateness. © 2012 American Association for Marriage and Family Therapy.

  17. Cobalt-doped Bi26Mo10O69: Crystal structure and conductivity

    NASA Astrophysics Data System (ADS)

    Mikhailovskaya, Z. A.; Buyanova, E. S.; Petrova, S. A.; Morozova, M. V.; Zhukovskiy, V. M.; Zakharov, R. G.; Tarakina, N. V.; Berger, I. F.

    2013-08-01

    A series of cobalt-doped bismuth molybdates were synthesized and investigated using X-ray powder diffraction, transmission electron microscopy and impedance spectroscopy. The ranges of solid solution were determined. Two new compounds, Bi1-xCox[Bi12O14]Mo5O34.5±δ (x=0.2) and Bi[Bi12O14]Mo5-yCoyO34.5±δ (y=0.2), which crystallise in monoclinic unit cells have been examined in detail by diffraction methods. Impedance spectroscopy measurements show that the studied materials are good ionic conductors with conductivity values about 5×10-3 S×cm-1 at 973 K and 1.7×10-4 S×cm-1 at 623 K, which are similar to conductivity values of yttrium substituted zirconia and (YSZ) gadolinium doped ceria (CGO).

  18. Efficient Charge Separation between Bi and Bi2 MoO6 for Photoelectrochemical Properties.

    PubMed

    Ma, Ying; Jia, Yulong; Wang, Lina; Yang, Min; Bi, Yingpu; Qi, Yanxing

    2016-04-18

    Herein, porous Bi/Bi2 MoO6 nanoparticles have been prepared by a facile in-situ reduction approach. Moreover, the morphology and Bi content of product could be controlled by varying the reaction time. By controlled fabrication, the desired porous Bi2 MoO6 nanostructure with incorporation of Bi was obtained and exhibited high photoelectric and photocatalytic activity. In particular, the samples yield a photocurrent density of 320 μA cm(-2) , which is 3.2 times that of the pure Bi2 MoO6 nanosheet (100 μA cm(-2) ) under the same conditions. UV/Vis diffuse reflectance spectroscopy analysis confirmed the surface plasmon resonance in the as-prepared porous nanoparticles. The improved photoelectric properties could be the synergistic effect of the porous structure with large surface area and effective electron-hole separations between Bi and Bi2 MoO6 .

  19. Kinetics of the lipase-catalyzed synthesis of glucose esters in acetone.

    PubMed

    Arcos, J A; Hill, C G; Otero, C

    2001-04-20

    A simple kinetic model derived from a ping-pong bi-bi mechanism is proposed to describe the lipase-catalyzed esterification of glucose with fatty acids. The mathematical expressions derived from this model have been tested using several sets of data obtained from reactions carried out under different reaction conditions. The predicted values provide very good fits of the experimental data for temperatures from 30 to 60 degrees C, enzyme loadings from 90 to 180 mg, and fatty acid concentrations from 0.33M to 1M. Experiments conducted at different temperatures permit one to estimate an activation energy of approximately 12 kcal/mol for the rate-limiting step of the reaction (formation of the acyl-enzyme complex). The model also considers the kinetics of inactivation of the biocatalyst during the reaction. Copyright 2001 John Wiley & Sons, Inc.

  20. Dual coenzyme activities of high-Km aldehyde dehydrogenase from rat liver mitochondria.

    PubMed

    Tsai, C S; Senior, D J

    1990-04-01

    Various kinetic approaches were carried out to investigate kinetic attributes for the dual coenzyme activities of mitochondrial aldehyde dehydrogenase from rat liver. The enzyme catalyses NAD(+)- and NADP(+)-dependent oxidations of ethanal by an ordered bi-bi mechanism with NAD(P)+ as the first reactant bound and NAD(P)H as the last product released. The two coenzymes presumably interact with the kinetically identical site. NAD+ forms the dynamic binary complex with the enzyme, while the enzyme-NAD(P)H complex formation is associated with conformation change(s). A stopped-flow burst of NAD(P)H formation, followed by a slower steady-state turnover, suggests that either the deacylation or the release of NAD(P)H is rate limiting. Although NADP+ is reduced by a faster burst rate, NAD+ is slightly favored as the coenzyme by virtue of its marginally faster turnover rate.

  1. Lipase catalyzed transesterification of ethyl butyrate synthesis in n-hexane- a kinetic study.

    PubMed

    Devi, N Annapurna; Radhika, G B; Bhargavi, R J

    2017-08-01

    Kinetics of lipase catalyzed transesterification of ethyl caprate and butyric acid was investigated. The objective of this work was to propose a reaction mechanism and develop a rate equation for the synthesis of ethyl butyrate by transesterification using surfactant coated lipase from Candida rugosa. The reaction rate could be described in terms of Michaelis-Menten equation with a Ping-Pong Bi-Bi mechanism and competitive inhibition by both the substrates. The values of kinetic parameters computed were Vmax = 2.861 μmol/min/mg; Km(acid) = 0.0746 M; Km(ester) = 0.125 M; Ki acid = 0.450 M. This study indicated a competitive enzyme inhibition by butyric acid during lipase catalyzed transesterification reaction. Experimental observations had clearly indicated that the substrates as well as product act as dead-end inhibitors.

  2. Enhanced biocatalytic activity of immobilized Pseudomonas cepacia lipase under sonicated condition.

    PubMed

    Badgujar, Kirtikumar C; Pai, Poorna A; Bhanage, Bhalchandra M

    2016-02-01

    The present work reports the use of biocatalyst and ultrasound for greener synthesis of cinnamyl propionate. The lipase Pseudomonas cepacia was immobilized on a copolymer of hydroxypropyl methyl cellulose and polyvinyl alcohol. This biocatalyst was u sed for ultrasound-assisted synthesis of cinnamyl propionate with the detailed optimization of various reaction parameters. Besides this, protocol was extended to synthesize various industrially important propionate esters. In addition to this, different enzyme-kinetic parameters such as r max and K m(vinyl propionate), K m(cinnamyl alcohol) and K i(cinnamyl alcohol) were studied which presented ordered bi-bi mechanism with an inhibition by cinnamyl alcohol. The developed biocatalyst demonstrated enhancement in catalytic activity and recyclability up to five recycles. Moreover, the biocatalyst was tested to investigate the effects of sonication via various characterization techniques such as scanning electron microscopy, thermogravimetry, and water content analysis.

  3. Dopant activation mechanism of Bi wire-δ-doping into Si crystal, investigated with wavelength dispersive fluorescence x-ray absorption fine structure and density functional theory.

    PubMed

    Murata, Koichi; Kirkham, Christopher; Shimomura, Masaru; Nitta, Kiyofumi; Uruga, Tomoya; Terada, Yasuko; Nittoh, Koh-Ichi; Bowler, David R; Miki, Kazushi

    2017-04-20

    We successfully characterized the local structures of Bi atoms in a wire-δ-doped layer (1/8 ML) in a Si crystal, using wavelength dispersive fluorescence x-ray absorption fine structure at the beamline BL37XU, in SPring-8, with the help of density functional theory calculations. It was found that the burial of Bi nanolines on the Si(0 0 1) surface, via growth of Si capping layer at 400 °C by molecular beam epitaxy, reduced the Bi-Si bond length from [Formula: see text] to [Formula: see text] Å. We infer that following epitaxial growth the Bi-Bi dimers of the nanoline are broken, and the Bi atoms are located at substitutional sites within the Si crystal, leading to the shorter Bi-Si bond lengths.

  4. Lipase-catalyzed synthesis of (S)-naproxen ester prodrug by transesterification in organic solvents.

    PubMed

    Tsai, S W; Tsai, C S; Chang, C S

    1999-06-01

    A lipase-catalyzed enantioselective transesterification process was developed for the synthesis of (S)-naproxen 2-N-morpholinoethyl ester prodrug from racemic 2,2,2-trifluoroethyl naproxen ester in organic solvents. By selecting isooctane and 37 degrees C as the best solvent and temperature, the apparent fits of the initial conversion rates for transesterification and hydrolysis side reaction suggest a ping-pong Bi-Bi enzymatic mechanism with the alcohol as a competitive enzyme inhibitor. Improvements in the initial conversion rate and the productivity for the desired (S)-ester product were obtained after comparing with the result of an enantioselective esterification process. Studies of water content in isooctane and alcohol containing various N,N-dialkylamino groups on the enzyme activity and enantioselectivity, as well as the recovery of (S)-ester product by using extraction, were also reported.

  5. Charge-deposition in two-layer systems irradiated by electrons

    NASA Astrophysics Data System (ADS)

    Alouani-Bibi, F.; Lazurik, V. T.; Rogov, Yu. V.; Tabata, T.

    2001-02-01

    On the basis of the data obtained by computer simulation and theoretical analysis of the charge-deposition density in single slabs located in vacuum (Alouani-Bibi et al., 1999. Can. J. Phys. 77(2), 127-136), a semi-empirical model that describes the charge-deposition distributions in two-layer systems irradiated by fast electron beams has been developed. The slabs considered are made of materials with atomic numbers from 4 to 79 and thicknesses from 0.5 to 50 mg/cm 2 irradiated by electron beams with energies from 1 to 10 MeV. Comparisons have been made of the results obtained by the present model and those obtained by the PENELOPE code. Results of charge-deposition distributions for different material combinations of the layers are also presented.

  6. Development of Improved Analysis of 1-D Non-Local Electron Parallel Heat Transport in Divertor Plasmas

    NASA Astrophysics Data System (ADS)

    Kim, Chang-Geun; Alouani Bibi, Fathallah; Matte, Jean-Pierre; Rognlien, Thomas D.; Stotler, Daren P.

    2003-10-01

    Improved analysis of 1-D non-local electron parallel heat transport in divertor plasmas is investigated. In the divertor of NSTX, as well as in other magnetic confinement devices, there are steep temperature gradients parallel to the direction of the magnetic field, especially near the neutralizer plates. Strong temperature gradients modify the electrons' thermal transport. A recently developed delocalization formula [1] is implemented in the "UEDGE" fluid edge plasma simulation code. UEDGE simulations are performed using this non-local electron heat flow formula (without any external heating source), and are compared to runs made with the more traditional flux limited heat diffusion formula. . [1] F. Alouani Bibi and J.P. Matte, Phys. Rev. E 66, 066414 (2002)

  7. Component Reconnexion at the Heliopause

    NASA Astrophysics Data System (ADS)

    Moore, T. E.; Alouani-Bibi, F.; Opher, M.; Toth, G.; McComas, D. J.

    2010-12-01

    Extended X lines of component reconnection at the heliopause are derived from 3D MHD simulations of the steady state heliosphere (Alouani-Bibi et al 2010, Opher et al 2009). A similar study established this technique to describe the extended shape of reconnection X-lines at the magnetosphere, as result of its interaction with the interplanetary field of varying orientation (Moore et al., 2002). At the heliopause, reconnection X-line candidates are derived on the basis of geometrical criteria, allowing for shear angles between the interacting fields of less than 180 degree (Cowley 1976) and properties of the magnetic fields and flows outside (interstellar medium) and inside (interplanetary space beyond the termination shock) the heliopause. Kinetic effects addressed by Swisdak et al. (2009) and Opher et al. (2010) can inhibit large scale component reconnection, leading to more localized and nearly anti-parallel reconnection, possibly accounting for the persistent hot spot in IBEX heliopause ribbon.

  8. Development of improved analysis of non-local electron parallel heat transport in divertor plasmas

    NASA Astrophysics Data System (ADS)

    Allais, Fabrice; Alouani Bibi, Fathallah; Kim, Chang-Geun; Matte, Jean-Pierre; Stotler, Daren P.

    2004-03-01

    Parallel electron heat transport in divertor plasmas is investigated. Our electron kinetic code "FPI" has been upgraded to take into account the hydrogen's atomic physics, including 30 energy levels in the computation. This required important improvements in the numerical algorithms in order to run the code within a reasonable time and compute the effects of each inelastic process. Their effects on non-local transport and the large enhancement of the effective (i.e. including ionization via excited states) ionization rates in the cold plasma due to nonlocal transport will be presented. A non-local electron heat flow formula [1] has been adapted and implemented in the "UEDGE" code. Simulations using it were compared to runs made with the more traditional flux limited heat diffusion formula. Considerable differences were seen in the temperature profiles. [1] F. Alouani Bibi and J.P. Matte, Phys. Rev. E 66, 066414 (2002)

  9. Kinetic study of porcine kidney betaine aldehyde dehydrogenase.

    PubMed

    Figueroa-Soto, C G; Valenzuela-Soto, E M

    2000-03-16

    Porcine kidney betaine aldehyde dehydrogenase (EC 1.2.1.8) kinetic properties were determined at low substrate concentrations. The double-reciprocal plots of initial velocity versus substrate concentration are linear and intersect at the left of the 1/v axis and showed substrate inhibition with betaine aldehyde. Studies of inhibition by NADH and dead-end analogs showed that NADH is a mixed inhibitor against NAD(+) and betaine aldehyde. AMP is competitive with respect to NAD(+) and mixed with betaine aldehyde. Choline is competitive against betaine aldehyde and uncompetitive with respect to NAD(+). The kinetic behavior is consistent with an Iso-Ordered Bi-Bi Steady-State mechanism. Copyright 2000 Academic Press.

  10. Mn(CO)[sub 5]C(O)-p-C[sub 6]H[sub 5]CH[sub 3]-catalyzed hydrosilane SiH/SiD exchange. Evidence from a kinetics study implicating coordinatively unsaturated manganese silyl intermediates

    SciTech Connect

    Gregg, B.T.; Cutler, A.R. )

    1993-06-01

    The manganese p-toluoyl complex Mn(CO)[sub 5]C(O)-p-CH[sub 3]C[sub 6]H[sub 4] catalyzes SiH/SiD exchange between DSiMe[sub 2]Ph and HSiMe[sub 2]Et at room temperature in C[sub 6]D[sub 6]. The preequilibrium kinetics are consistent with a second-order isotope exchange reaction; plots of initial velocities [nu] against [HSiMe[sub 2]Et] further established saturation kinetics. Lineweaver-Burk plots are in accord with a ping-pong bi-bi mechanism that operates under rapid equilibrium conditions and involves coordinatively unsaturated manganese silyls, (CO)[sub 4]MnSiMe[sub 2/R], as active catalysts. 29 refs., 2 figs.

  11. Zinc Oxide Nanoparticles Supported Lipase Immobilization for Biotransformation in Organic Solvents: A Facile Synthesis of Geranyl Acetate, Effect of Operative Variables and Kinetic Study.

    PubMed

    Patel, Vrutika; Shah, Chandani; Deshpande, Milind; Madamwar, Datta

    2016-04-01

    The present study describes grafting of zinc oxide (ZnO) nanoparticles with polyethyleneimine (PEI) followed by modification with glutraldehyde used as the bridge for binding the enzyme to support. The prepared nanocomposites were then characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy, utilized for synthesis of geranyl acetate in n-hexane. Among all the three prepared nanocomposites (ZnO + PEI, ZnO + PEI + SAA, ZnO + PEI + GLU), Candida rugosa lipase immobilized on ZnO-PEI-GLU was found to be best for higher ester synthesis. The operating conditions that maximized geranyl acetate resulted in the highest yield of 94 % in 6 h, molar ratio of 0.1:0.4 M (geraniol/vinyl acetate) in the presence of n-hexane as reaction medium. Various kinetic parameters such as V max, K i(G), K m(G), and K m(VA) were determined using nonlinear regression analysis for order bi-bi mechanism. The kinetic study showed that reaction followed order bi-bi mechanism with inhibition by geraniol. Activation energy (E a ) was found to be lower for immobilized lipase (12.31 kJ mol(-1)) than crude lipase (19.04 kJ mol(-1)) indicating better catalytic efficiency of immobilized lipase. Immobilized biocatalyst demonstrated 2.23-fold increased catalytic activity than crude lipase and recycled 20 times. The studies revealed in this work showed a promising perspective of using low-cost nanobiocatalysts to overcome the well-known drawbacks of the chemical-catalyzed route.

  12. Effect of Upper Mantle Heterogeneities on Lithosphere Stresses and Topography

    NASA Astrophysics Data System (ADS)

    Osei Tutu, A.; Steinberger, B.; Rogozhina, I.; Sobolev, S. V.

    2016-12-01

    The orientation and magnitude of lithosphere stresses give us knowledge about most of the processes within the Earth that are not easy to observe. It has been established (Steinberger, Schmeling, and Marquart 2001) that large contribution of the forces producing lithosphere stresses have their source origination from the buoyancies of both the upper and lower mantle acting beneath the lithosphere. The contribution of the crustal thickness to the stresses has been estimated to be less than 10% (Steinberger et al. 2001) in most region and increases in areas with high gravitational potential energy like the Himalayas. In most of these studies, the effect of the crust was determined separately by computing the gravitational potential energy from the crust (Ghosh et al. 2013) and applied as correction. (Artyushkov 1973) showed that the inhomogeneous nature of the crust contribute to the stresses observed as against using constant lithosphere thickness in most studies, due to the complexities for implementing a variable lithosphere. We seek extend the approach of Ghosh et al. (2013) by coupling the Crust 1.0 (Laske et al. 2013) to a varaible lithosphere thickness in our numerical method. Using a 3D global lithosphere-asthenosphere model (Popov and Sobolev 2008) with visco-elasto-plastic rheology, coupled at 300 km depth to a mantle modeled with a spectral technique (Hager and O'Connell, 1981), we compute lithosphere stresses and topography. we compare our model with observations; the World Stress Map, Global Strain Rate Map and the observed topgraphy. We use S40RTS seismic tomography below 300 km depth, with radial viscosity distribution (Steinberger et al 2006). To account for all the heterogeneities in the upper mantle (300 km) we used different 3D temperatures models setups. The first model is the thermal lithosphere model (Artemieva and Mooney, 2001) in continental regions and assumes half-space cooling of sea floor with age (Müller et al. 2008) for oceans. For the

  13. Role of temperature differences between surface and deep reservoirs in geyser dynamics: Insights from laboratory experiments

    NASA Astrophysics Data System (ADS)

    Munoz Saez, C.; Shteinberg, A.; Manga, M.

    2012-12-01

    Geysers are springs that produce episodic eruptions of steam, liquid water, and non-condensable gases. Their eruptions are smaller and more frequent than other eruptive processes (volcanic, or hydrothermal eruptions), providing a feasible natural laboratory to understand eruptive processes. Moreover, the fluid dynamics of geysers probe processes that operate in more inaccessible geothermal systems. We developed laboratory experiments to understand the role of the surface temperature on geyser dynamics. For the experimental model, we followed to model developed by Steinberg et al. (1982), which produced periodic eruptions. In this experimental model, eruptions are driven by the ascent of bubbles. The "explosive" ejection of fluid occurs when bubbles reach the surface of the conduit. The eruption of a bubble influences the nucleation on the next bubble through the pressure changes in the conduit. The experimental apparatus consists of a bottom reservoir and a vertical conduit that opens into an upper chamber that collects and returns liquid to the reservoir after the eruption. The reservoir was heated from below at a constant rate. The fluid used was Freon 113, which has a boiling point of 48°C. Temperature in the upper part of the tube was varied between 0° to 20°C. As we increase the temperature difference between the reservoir and the surface of the tube we find (1) that vapor contained in the upper part of bubble tends condense, impeding its ascent to the surface, (2) an increase the number of bubbles generated during the time between eruptions, (3) that the volume of vapor in the tube remain almost constant during the period between eruptions (4) an increase the frequency of eruptions, (5) an increase the escape speed of fluid from the tube, and (6) an increase in Reynolds number. We interpret these results in terms of heat transport by the rising bubbles. Bubbles transport the heat as latent heat of evaporation. Because the amount of heating was the same in

  14. Adolescent development and the regulation of youth crime.

    PubMed

    Scott, Elizabeth S; Steinberg, Laurence

    2008-01-01

    Elizabeth Scott and Laurence Steinberg explore the dramatic changes in the law's conception of young offenders between the end of the nineteenth century and the beginning of the twenty-first. At the dawn of the juvenile court era, they note, most youths were tried and punished as if they were adults. Early juvenile court reformers argued strongly against such a view, believing that the justice system should offer young offenders treatment that would cure them of their antisocial ways. That rehabilitative model of juvenile justice held sway until a sharp upswing in youth violence at the end of the twentieth century led both public opinion and public policy toward a view that youths should be held to the same standard of criminal accountability as adults. Lawmakers seemed to lose sight of developmental differences between adolescents and adults. But Scott and Steinberg note that lawmakers and the public appear now to be rethinking their views once more. A justice system that operates on the principle of "adult time for adult crime" now seems to many to take too little note of age and immaturity in calculating criminal punishment. In 2005 the United States Supreme Court abolished the juvenile death penalty as cruel and unusual punishment, emphasizing that the immaturity of adolescents made them less culpable than adult criminals. In addition, state legislatures recently have repealed or moderated some of the punitive laws they recently enacted. Meanwhile, observe the authors, public anger has abated and attitudes toward young offenders have softened somewhat. In response to these changes, Scott and Steinberg argue that it is appropriate to reexamine juvenile justice policy and to devise a new model for the twenty-first century. In this article, they propose what they call a developmental model. They observe that substantial new scientific evidence about adolescence and criminal activity by adolescents provides the building blocks for a new legal regime superior to

  15. The really "stealth" mantle metasomatism

    NASA Astrophysics Data System (ADS)

    Puziewicz, Jacek; Matusiak-Małek, Magdalena; Ntaflos, Theodoros; Grégoire, Michel; Kukuła, Anna; Wojtulek, Piotr

    2015-04-01

    The Lower Silesian/Upper Lusatian domain of European subcontinental lithospheric mantle is dominated by two kinds of harzburgites: A - not affected or slightly affected by silicate melt metasomatism related to migration of lavas during formation of Cenozoic Central European Volcanic Province, and B - strongly overprinted by those lavas (Puziewicz et al. 2015, IJES, DOI 10.1007/s00531-014-1134-2). The study of Matusiak-Małek et al. (2014, J Petrol 55, 1799-1828) shows that the A harzburgites untouched by metasomatic events contain no clinopyroxene. Part of the A harzburgites contains clinopyroxene which has "primary" appearance but was added to the host during metasomatic event(s) overprinting the primary mineral assemblage. The metasomatic nature of this clinopyroxene can be recognized by its major and trace element chemical composition, and the mineral is a good example of the "stealth" metasomatic phase (O'Reilly & Griffin 2013, Springer). One of the typical features of this kind of clinopyroxene are LREE enriched REE patterns. We have discovered single xenoliths containing clinopyroxene with LREE depleted patterns in Steinberg near Görlitz (Lower Silesian/Upper Lusatian Region) and in Feldstein near Suhl (Heldburger Gangschar in Thuringia). Usually these kind of REE patterns is considered to be a relic of primary mineral assemblage subjected to strong melt-depletion. However, clinopyroxene from Steinberg is texturally late phase. Its major element chemical composition suggests that it is not a residue after partial melting, but a late silicate-melt metasomatic addition to the host rock which preceded the xenolith entrainment in the erupting lava. Thus, the metasomatising melt must have had characteristics enabling the precipitation of LREE depleted clinopyroxene. The existence of such the melts is clearly shown by the clinopyroxene from websterite cumulate from Dobkovičky in Eger Rift (Ackerman et al. 2012, J Geosci 58, 199-219), which has LREE depleted

  16. Metal-Metal Bonding in Uranium-Group 10 Complexes.

    PubMed

    Hlina, Johann A; Pankhurst, James R; Kaltsoyannis, Nikolas; Arnold, Polly L

    2016-03-16

    Heterobimetallic complexes containing short uranium-group 10 metal bonds have been prepared from monometallic IU(IV)(OAr(P)-κ(2)O,P)3 (2) {[Ar(P)O](-) = 2-tert-butyl-4-methyl-6-(diphenylphosphino)phenolate}. The U-M bond in IU(IV)(μ-OAr(P)-1κ(1)O,2κ(1)P)3M(0), M = Ni (3-Ni), Pd (3-Pd), and Pt (3-Pt), has been investigated by experimental and DFT computational methods. Comparisons of 3-Ni with two further U-Ni complexes XU(IV)(μ-OAr(P)-1κ(1)O,2κ(1)P)3Ni(0), X = Me3SiO (4) and F (5), was also possible via iodide substitution. All complexes were characterized by variable-temperature NMR spectroscopy, electrochemistry, and single crystal X-ray diffraction. The U-M bonds are significantly shorter than any other crystallographically characterized d-f-block bimetallic, even though the ligand flexes to allow a variable U-M separation. Excellent agreement is found between the experimental and computed structures for 3-Ni and 3-Pd. Natural population analysis and natural localized molecular orbital (NLMO) compositions indicate that U employs both 5f and 6d orbitals in covalent bonding to a significant extent. Quantum theory of atoms-in-molecules analysis reveals U-M bond critical point properties typical of metallic bonding and a larger delocalization index (bond order) for the less polar U-Ni bond than U-Pd. Electrochemical studies agree with the computational analyses and the X-ray structural data for the U-X adducts 3-Ni, 4, and 5. The data show a trend in uranium-metal bond strength that decreases from 3-Ni down to 3-Pt and suggest that exchanging the iodide for a fluoride strengthens the metal-metal bond. Despite short U-TM (transition metal) distances, four other computational approaches also suggest low U-TM bond orders, reflecting highly transition metal localized valence NLMOs. These are more so for 3-Pd than 3-Ni, consistent with slightly larger U-TM bond orders in the latter. Computational studies of the model systems (PH3)3MU(OH)3I (M = Ni, Pd) reveal

  17. Los Alamos Radiation Hydrocode Models of Asteroid Destruction by an Internal Explosion

    NASA Astrophysics Data System (ADS)

    Weaver, R.; Plesko, C. S.

    2009-12-01

    Disruption of a potentially hazardous object (PHO) by a conventional or nuclear subsurface burst is considered has been popularized in media presentations and is considered as one possible method of impact-hazard mitigation. We present RAGE radiation hydrocode models of the shock-generated disruption of PHOs by subsurface nuclear bursts using scenario-specific models from authentic RADAR shape models. We will show 2D and 3D models for the disruption by a large energy source at the center of such PHO models (10 Mton TNT equivalent) , specifically for Itokawa and Golevka. If possible, our RAGE model calculations will be compared to M. Boslough’s (Sandia National Laboratory) results from his similar simulations with a different code. As time permits, parametric studies will be done on source energy (from 1 Mton to 10 Mton) and on the parameters in the Steinberg-Guinan strength model used.

  18. Childhood experience and the development of reproductive strategies.

    PubMed

    Belsky, Jay

    2010-02-01

    Even though a great deal of mainstream developmental psychology is devoted to understanding whether and how experiences in childhood shape psychological and behavioral development later in life, little theoretical attention has been paid to why such cross-time influences should characterize human development. This is especially true with respect to the well-studied determinants of mating, pair bonding and parenting. Theoretically, Draper and Harpending (1982), Belsky, Steinberg and Draper (1991), Ellis (2004) and Chisholm (1996) have all addressed this lacuna, stimulating research on linkages between childhood experience and reproductive strategy which is summarised herein. Concern for experiential effects on pubertal timing distinguishes this line of inquiry from more traditional developmental studies because an evolutionary perspective suggests that experiences in the family might affect somatic development. Twenty years since BSD advanced their prediction, it seems clear that female pubertal timing is related to select aspects of early family experience.

  19. Toward an Evo-Devo Theory of Reproductive Strategy, Health, and Longevity: Commentary on Rickard et al. (2014).

    PubMed

    Belsky, Jay

    2014-01-01

    Rickard and associates (2014, this issue) challenge the theoretical claim that early developmental experiences influence sexual development and behavior as a result of the continuity of early- and later-life environments over the course of human history (Belsky, Steinberg, & Draper, 1991). Instead, they contend that sexual development, health, and longevity are regulated by internal (bodily) state reflective of morbidity and mortality risk. By highlighting the importance of internal state-and thereby underscoring the value of focusing on it and on the external environment early in life-these theoreticians continue the tradition of extending a line of human evolutionary-developmental ("evo-devo") theorizing in important ways. In fact, what they make clear is that what was originally conceived as an evolutionary theory of socialization by Belsky et al. (1991) can and should develop into an evolutionary-developmental life-course theory of reproductive strategy, health, and longevity. © The Author(s) 2013.

  20. Using nonlinear optimization methods to reverse engineer liner material properties from EFP tests

    SciTech Connect

    Murphy, M.J.; Baker, E.L.

    1995-02-27

    The utility of variable metric nonlinear optimization methods for reverse engineering liner material constitutive modeling parameters is described. We use an effective new code created by coupling the nonlinear optimization code NLQPEB with the DYNA2D finite element hydrocode. The optimization code determines the ``best`` set of liner material properties by running DYNA2D in a loop, varying the liner model constitutive parameters, and minimizing the difference between the EFP profiles of the calculation and experiment. The results of four different EFP warhead tests with the same copper liner material are used to determine material parameters for the Steinberg-Guinan, Johnson-Cook, & Armstrong-Zerilli models. In a companion paper we describe the successful application of this methodology to the forward engineering of liner contours to achieve desired EFP shapes. The methodology of utilizing a coupled optimization/finite element code provides a significant improvement in warhead designs and the warhead design process.

  1. Experimental and numerical investigations of beryllium strength models using the Rayleigh-Taylor instability

    SciTech Connect

    Henry de Frahan, M. T.; Belof, J. L.; Cavallo, R. M.; Raevsky, V. A.; Ignatova, O. N.; Lebedev, A.; Ancheta, D. S.; El-dasher, B. S.; Florando, J. N.; Gallegos, G. F.; Johnsen, E.; LeBlanc, M. M.

    2015-06-14

    A recent collaboration between LLNL and VNIIEF has produced a set of high explosive driven Rayleigh-Taylor strength data for beryllium. Design simulations using legacy strength models from Steinberg-Lund and Preston-Tonks-Wallace (PTW) suggested an optimal design that would delineate between not just different strength models, but different parameters sets of the PTW model. Application of the models to the post-shot results, however, shows close to classical growth. We characterize the material properties of the beryllium tested in the experiments. We also discuss recent efforts to simulate the data using the legacy strength models as well as the more recent RING relaxation model developed at VNIIEF. Finally, we present shock and ramp-loading recovery experiments conducted as part of the collaboration.

  2. Experimental and numerical investigations of beryllium strength models using the Rayleigh-Taylor instability

    SciTech Connect

    Henry de Frahan, M. T. Johnsen, E.; Belof, J. L.; Cavallo, R. M.; Ancheta, D. S.; El-dasher, B. S.; Florando, J. N.; Gallegos, G. F.; LeBlanc, M. M.; Raevsky, V. A.; Ignatova, O. N.; Lebedev, A.

    2015-06-14

    We present a set of high explosive driven Rayleigh-Taylor strength experiments for beryllium to produce data to distinguish predictions by various strength models. Design simulations using existing strength model parameterizations from Steinberg-Lund and Preston-Tonks-Wallace (PTW) suggested an optimal design that would delineate between not just different strength models, but different parameters sets of the PTW model. Application of the models to the post-shot results, however, suggests growth consistent with little material strength. We focus mostly on efforts to simulate the data using published strength models as well as the more recent RING relaxation model developed at VNIIEF. The results of the strength experiments indicate weak influence of strength in mitigating the growth with the RING model coming closest to predicting the material behavior. Finally, we present shock and ramp-loading recovery experiments.

  3. Congressional liaison task force - a briefing of the October 1994 meeting

    SciTech Connect

    1994-12-31

    As the US Senate overturned roadblocks attempting-unsuccessfully-to halt passage of the elementary and secondary education reauthorization legislation representatives from several federal agencies and laboratories addressed Congressional Liaison Task Force (CLTF) participants October 12th. They spoke about their commitment, programs, and accomplishments toward the nation`s science knowledge, particularly at the precollege level. Marjorie S. Steinberg legislative assistant to bill cosponsor Sen. Jeff Bingaman (DNM), and Gary Allen, Triangle Coalition director of Governmental affairs, spoke about education legislation and specifically about the Technology for Education Act that was on the Senate floor for a vote in October and now is law. Bruce A. Fuchs talked about the National Institute of Health`s (NIH) work in science literacy and education. The National Aeronautics and Space Administration`s (NASA) Frank C. Owens and Eddie Anderson contributed to this report.

  4. Geometry of the melting interface in cylindrical metal rods under microgravity conditions

    NASA Astrophysics Data System (ADS)

    Ward, Nicolas R.; Steinberg, Ted A.

    2007-05-01

    The melting interface geometries present within cylindrical iron rods in microgravity are examined. Melting samples are quenched in microgravity by immersion in a water bath. Samples are sectioned on multiple planes and photo microscopy analysis is used to determine the shape of the melting interface on each plane. Images from multiple cross-sections are assembled to produce a three-dimensional representation of the melting interface present in microgravity. Iron rods are shown to have an asymmetric, convex melting interface in microgravity, with a significantly different (increased) heat transfer area compared to the planar normal-gravity case. The change in surface area of the melting interface between normal gravity and microgravity is shown to provide excellent agreement with the observed change in melting rate, as predicted by simple one-dimensional heat transfer analysis. To cite this article: N.R. Ward, T.A. Steinberg, C. R. Mecanique 335 (2007).

  5. A review of the kinetic statistical strength model

    SciTech Connect

    Attia, A.V.

    1996-03-11

    This is a review of the Kinetic-Statistical Strength (KSS) model described in the report ``Models of Material Strength, Fracture and Failure`` by V. Kuropatenko and V. Bychenkov. The models for metals subjected to high strain rates (explosions) are focussed on. Model implementation appears possible in a hydrocode. Applying the model to the shock response of metals will require a data source for the Weibull parameter {alpha}{sub u}, short of measuing the strength of specimens of various sizes. Model validation will require more detail on the experiments successfully calculated by SPRUT. Evaluation of the KSS model is needed against other existing rate-dependent models for metals such as the Steinberg-Lund or MTS model on other shock experiments.

  6. Quantum mechanics: A new chapter?

    NASA Astrophysics Data System (ADS)

    Hofer, Werner A.

    2012-12-01

    We review the conceptual problems in quantum mechanics on a fundamental level. It is shown that the proposed model of extended electrons and a clear understanding of rotations in three dimensional space solve a large part of these problems, in particular the problems related to the ontological status and physical meaning of wavefunctions. It also solves the problem of non-locality. The experimental results obtained in Yves Couder's group and theoretical results by Gerdard Grössing indicate that the wave-like distribution of trajectories of electrons in interference experiments are most likely due to the quantized interactions leading to a discrete set of transferred momenta. A separate experimental confirmation of this interpretation for double-slit interferometry of photons has been given by the group of Steinberg.

  7. Dynamic Strength of Tantalum under impact

    NASA Astrophysics Data System (ADS)

    Glam, Benny; Werdiger, Meir; Pistinner, Shlomi

    2013-06-01

    Plane impact experiments of double shock and shock-rarefaction in Tantalum were carried out in a gas gun. VISAR diagnostics has been implemented to measure the particle velocity and the free surface velocity. The VISAR information was utilized to study the dynamic strength of Tantalum under compression and tension. The pressure in the experiments was below 35 GPa. In this pressure range the dominant mechanism is expected to be dislocation motion. A 1-d hydrodynamic code was used in order to match various strength models. As expected, both the Johnson-Cook and the Guinan-Steinberg models do not reproduce the experimental results. Therefore in this paper we compare the Zerilli-Armstrong model which has been recently calibrated at strain rate of 6 x 103 s-1 using the split Kowalsky-Hopkinson bar to our experimental results at strain rate of 106 s-1.

  8. All-order dispersion cancellation and energy-time entangled state.

    PubMed

    Ryu, Jinsoo; Cho, Kiyoung; Oh, Cha-Hwan; Kang, Hoonsoo

    2017-01-23

    Dispersion cancellation with an energy-time entangled photon pair in Hong-Ou-Mandel (HOM) interference is one phenomenon that reveals the nonclassical nature of the entangled photon pair. This phenomenon has been observed in materials with very weak dispersions. If the higher-order dispersion coefficient is non-negligible, then the experiment must be modified to realize dispersion cancellation. All-order dispersion cancellation using balanced dispersion was suggested by Steinberg. However, the same phenomenon is expected to occur even if a photon pair is not entangled. This behaviour can be explained by path indistinguishability with identical dispersion. To achieve an all-order dispersion experiment that cannot be explained classically, we modified the experiment and performed another all-order dispersion cancellation experiment that cannot be explained by identical dispersion. This is the first demonstration of nonclassical all-order dispersion cancellation.

  9. Quality of Early Family Relationships and Individual Differences in the Timing of Pubertal Maturation in Girls: A Longitudinal Test of an Evolutionary Model

    PubMed Central

    Ellis, Bruce J.; McFadyen-Ketchum, Steven; Dodge, Kenneth A.; Pettit, Gregory S.; Bates, John E.

    2009-01-01

    In an 8-year prospective study of 173 girls and their families, the authors tested predictions from J. Belsky, L. Steinberg, and P. Draper's (1991) evolutionary model of individual differences in pubertal timing. This model suggests that more negative–coercive (or less positive–harmonious) family relationships in early childhood provoke earlier reproductive development in adolescence. Consistent with the model, fathers' presence in the home, more time spent by fathers in child care, greater supportiveness in the parental dyad, more father–daughter affection, and more mother–daughter affection, as assessed prior to kindergarten, each predicted later pubertal timing by daughters in 7th grade, The positive dimension of family relationships, rather than the negative dimension, accounted for these relations. In total, the quality of fathers' investment in the family emerged as the most important feature of the proximal family environment relative to daughters' pubertal timing. PMID:10474213

  10. CACNA1H missense mutations associated with amyotrophic lateral sclerosis alter Cav3.2 T-type calcium channel activity and reticular thalamic neuron firing.

    PubMed

    Rzhepetskyy, Yuriy; Lazniewska, Joanna; Blesneac, Iulia; Pamphlett, Roger; Weiss, Norbert

    2016-11-01

    Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. In a recent study by Steinberg and colleagues, 2 recessive missense mutations were identified in the Cav3.2 T-type calcium channel gene (CACNA1H), in a family with an affected proband (early onset, long duration ALS) and 2 unaffected parents. We have introduced and functionally characterized these mutations using transiently expressed human Cav3.2 channels in tsA-201 cells. Both of these mutations produced mild but significant changes on T-type channel activity that are consistent with a loss of channel function. Computer modeling in thalamic reticular neurons suggested that these mutations result in decreased neuronal excitability of thalamic structures. Taken together, these findings implicate CACNA1H as a susceptibility gene in amyotrophic lateral sclerosis.

  11. Revisiting the impact of part-time work on adolescent adjustment: distinguishing between selection and socialization using propensity score matching.

    PubMed

    Monahan, Kathryn C; Lee, Joanna M; Steinberg, Laurence

    2011-01-01

    The impact of part-time employment on adolescent functioning remains unclear because most studies fail to adequately control for differential selection into the workplace. The present study reanalyzes data from L. Steinberg, S. Fegley, and S. M. Dornbusch (1993) using multiple imputation, which minimizes bias in effect size estimation, and 2 types of propensity score matching, to account for selection effects. In this sample (N = 1,792; Grades 10-11, M = 16.26), youth who begin working more than 20 hr per week evince declines in school engagement and increases in substance use and delinquency compared with youth who remain unemployed. Conversely, working 20 hr or less a week has negligible effects, positive or negative, on academic, psychological, or behavioral outcomes.

  12. U-0.75Ti and Ti-6Al-4V in Planar and Ballistic Impact Experiments

    NASA Astrophysics Data System (ADS)

    Herrmann, B.; Venkert, A.; Favorsky, V.; Shvarts, D.; Zaretsky, E.

    2004-07-01

    The response of U and Ti alloys has been studied in planar and ballistic impact experiments performed with a 25 mm light-gas gun. Free surface velocities were monitored by VISAR. The velocity profiles and the damage maps were simulated using 2D AUTODYN™ finite differences code. A modified Steinberg-Cochran-Guinan constitutive model was calibrated by simulating planar impact experiments. Bauschinger effect and a single-parameter spall model were added to describe the unloading and the tensile paths. The ballistic experiments were simulated by using the calibrated model. Softly recovered samples revealed different degrees of spall fracture (planar impact) and of adiabatic shear bands (ballistic experiments). The results demonstrate a possibility to combine experimental and numerical techniques, VISAR and AUTODYN, to calibrate constitutive models of solids in a wide range of shock-induced strain.

  13. Aluminum Rayleigh Taylor Strength Measurements and Calculations

    SciTech Connect

    Lindquist, M J; Cavallo, R M; Lorenz, K T; Pollaine, S M; Remington, B A; Raevsky, V A

    2007-01-10

    A traditional approach to the study of material strength has been revitalized at the Russian Federal Nuclear Center (VNIIEF). Rayleigh Taylor strength experiments have long been utilized to measure the material response of metals at high pressure and strain rates. A modulated (sinusoidal or sawtooth perturbation) surface is shocklessly (quasi-isentropically) accelerated by a high explosive (HE) driver, and radiography is used to measure the perturbation amplitude as a function of time. The Aluminum T-6061 targets are designed with several sets of two-dimensional sawtooth perturbations machined on the loading surface. The HE driver was designed to reach peak pressures in the range of 200 to 300 kbar and strain rates in the range of 10{sup 4} - 10{sup 6} s{sup -1}. The standard constitutive strength models, Steinberg-Guinan (SG) [1], Steinberg-Lund (SL) [2], Preston-Tonks-Wallace (PTW) [3], Johnson-Cooke (JC) [4], and Mechanical Threshold Stress (MTS) [5], have been calibrated by traditional techniques: (Hopkinson-Bar, Taylor impact, flyer plate/shock-driven experiments). The VNIIEF experimental series accesses a strain rate regime not attainable using traditional methods. We have performed a detailed numerical study with a two-dimensional Arbitrary Lagrangian Eulerian hydrodynamics computer code containing several constitutive strength models to predict the perturbation growth. Results show that the capabilities of the computational methodology predict the amplitude growth to within 5 percent of the measured data, thus validating both the code and the strength models under the given conditions and setting the stage for credible future design work using different materials.

  14. Depersonalization and derealization in self-report and clinical interview: The spectrum of borderline personality disorder, dissociative disorders, and healthy controls.

    PubMed

    Sar, Vedat; Alioğlu, Firdevs; Akyuz, Gamze

    2017-01-01

    Depersonalization (DEP) and derealization (DER) were examined among college students with and without borderline personality disorder (BPD) and/or dissociative disorders (DDs) by self-report and clinician assessment. The Steinberg Depersonalization Questionnaire (SDEPQ), the Steinberg Derealization Questionnaire (SDERQ), the Childhood Trauma Questionnaire, and the screening tool of the BPD section of the Structured Clinical Interview for DSM-IV (SCID-BPD) were administered to 1,301 students. Those with BPD (n = 80) according to the SCID-BPD and 111 non-BPD controls were evaluated using the Structured Clinical Interview for DSM-IV Dissociative Disorders by a psychiatrist blind to the diagnosis. Of the participants, 19.7% reported SDEPQ (17.8%) and/or SDERQ (11.0%) scores above cutoff levels and impairment from these experiences. Principal component analysis of 26 items of both scales yielded 4 factors: cognitive-emotional self-detachment, perceptual detachment, bodily self-detachment, and detachment from reality. Participants with concurrent DD and BPD had the highest scores for DEP and DER in the clinical interview and self-report. The total number of BPD criteria was associated with the severity of childhood trauma and dissociation. Both BPD and DD were associated with clinician-assessed and self-reported DER, self-reported DEP, and the cognitive-emotional self-detachment factor. Unlike BPD, DD was associated with clinician-assessed DEP, and BPD was related to the self-reported detachment from reality factor. Although the latter was correlated with the total childhood trauma score, possibly because of dissociative amnesia, clinician-assessed DER was not. Being the closest factor to BPD, the factor of detachment from reality warrants further study.

  15. [Short-term curative effects of Tantalum rod treatment in early avascular necrosis].

    PubMed

    Ye, Fu-Sheng; Ni, Zhe-Ji; Chu, Xiao-Bing; He, Bang-Jian; Li, Ju; Tong, Pei-Jian

    2013-08-01

    To explore the recent clinical curative effect of Tantalum rod in treating the early avascular necrosis. From January 2008 to November 2008, the 25 patients (39 hips) with early avascular necrosis accepted tantalum rod placement and included 9 males (11 hips) and 16 females (28 hips) with an average age of 37 years old ranging from 18 to 74 years old. Four patients (6 hips) caused by Alcoholic, 6 patients (8 hips) by hormone, 2 cases (2 hips) by traumatic, 13 cases (23 hips) by idiopathic. Steinberg preoperative stage involved 7 hips in period I, 24 hips in period II, 8 hips in period III. Curative effect analysis included preoperative and postoperative Harris score, radiographic changes and hip replacement for follow-up to accept the end of the femoral head survival rate. All patients were followed up for 6 to 47 months (averaged 37.4 months). All 12 hips imaging appeard progress,including tantalum rod exit in 1 hip, hip hemiarthroplasty collapse in 3 hips, the area increased to avascular necrosis in 8 hips. Six hips accepted total hip replacement, including imaging progress in 5 hips (41.7%, 5/12), no imaging progress in 1 hip (3.7%,1/27). All hips' Kaplan-Meier survival curves showed 6-month survival rate was (97.4 +/- 2.5)% after tantalum stick insertion, 1-year survival rate was (94.7 +/- 3.6), and 2-year survival rate was (88.6 +/- 5.4)%, 3-year survival rate was (72.5 +/- 11.2). It is effective for treatment of avascular necrosis of femoral head in Steinberg I and II by Tantalum rod, and it can effectively relieve femoral head replacement time.

  16. Bidirectional associations between bedtime parenting and infant sleep: Parenting quality, parenting practices, and their interaction.

    PubMed

    Philbrook, Lauren E; Teti, Douglas M

    2016-06-01

    In keeping with transactional conceptualizations of infant sleep development (Sadeh, Tikotzky, & Scher, 2010), the present study was an examination of longitudinal, bidirectional linkages between bedtime parenting (through direct observations of parenting practices and quality) and infant sleep across the first 6 months postpartum. In doing so, we also drew from Darling and Steinberg's (1993) conceptual model to examine parenting quality as a moderator of linkages between specific bedtime practices and infant sleep. Multilevel model analyses revealed that the strongest increases in infant nighttime sleep across the first 6 months occurred among infants of mothers who engaged in low levels of nursing at bedtime. Within-person linkages between mothers' emotional availability (EA) at bedtime, infant distress, and infant sleep were found, such that at time points when mothers were more emotionally available, infants were less distressed and slept more throughout the night. Several moderating effects of maternal EA on linkages between parenting practices and infant sleep were obtained that were consistent with predictions from Darling and Steinberg (1993). Higher maternal EA in combination with less close contact at bedtime was associated with more infant sleep across the night on average, and higher EA in combination with fewer arousing bedtime activities predicted more rapid increases in infant sleep with age. Finally, there was evidence of infant-driven effects, as higher infant nighttime distress predicted lower EA at subsequent time points. Results showcased the complex, reciprocal interplay between parents and infants in the development of infant sleep patterns and parenting behavior during the first 6 months postpartum. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  17. Probes of hydrogen tunneling with horse liver alcohol dehydrogenase at subzero temperatures.

    PubMed

    Tsai, S; Klinman, J P

    2001-02-20

    The temperature dependence of steady-state kinetics has been studied with horse liver alcohol dehydrogenase (HLADH) using protonated and deuterated benzyl alcohol as substrates in methanol/water mixtures between +3 and -50 degrees C. Additionally, the competitive isotope effects, k(H)/k(T) and k(D)/k(T), were measured. The studies indicate increasing kinetic complexity for wild-type HLADH at subzero temperatures. Consistent with earlier findings at 25 degrees C [Bahnson et al. (1993) Biochemistry 31, 5503], the F93W mutant shows much less kinetic complexity than the wild-type enzyme between 3 and -35 degrees C. An analysis of noncompetitive deuterium isotope effects and competitive tritium isotope effects leads to the conclusion that the reaction of F93W involves substantial hydrogen tunneling down to -35 degrees C. The effect of methanol on kinetic properties for the F93W mutant was analyzed, showing a dependence of competitive KIEs on the NAD(+) concentration. This indicates a more random bi--bi kinetic mechanism, in comparison to an ordered bi-bi kinetic mechanism in water. Although MeOH also affects the magnitude of the reaction rates and, to some extent, the observed KIEs, the ratio of ln k(H)/k(T) to ln k(D)/k(T) for primary isotope effects has not changed in methanol, and we conclude little or no change in kinetic complexity. Importantly, the degree of tunneling, as shown from the relationship between the secondary k(H)/k(T) and k(D)/k(T) values, is the same in water and MeOH/water mixtures, implicating similar trajectories for H transfer in both solvents. In a recent study of a thermophilic alcohol dehydrogenase [Kohen et al. (1999) Nature 399, 496], it was shown that decreases in temperatures below a transition temperature lead to decreased tunneling. This arises because of a change in protein dynamics below a break point in enzyme activity [Kohen et al. (2000) J. Am. Chem. Soc. 122, 10738-10739]. For the mesophilic HLADH described herein, an opposite

  18. Linking Hydrologic Alteration to Biological Impairment in Urbanizing Streams of the Puget Lowland, Washington, USA1

    PubMed Central

    DeGasperi, Curtis L; Berge, Hans B; Whiting, Kelly R; Burkey, Jeff J; Cassin, Jan L; Fuerstenberg, Robert R

    2009-01-01

    We used a retrospective approach to identify hydrologic metrics with the greatest potential for ecological relevance for use as resource management tools (i.e., hydrologic indicators) in rapidly urbanizing basins of the Puget Lowland. We proposed four criteria for identifying useful hydrologic indicators: (1) sensitive to urbanization consistent with expected hydrologic response, (2) demonstrate statistically significant trends in urbanizing basins (and not in undeveloped basins), (3) be correlated with measures of biological response to urbanization, and (4) be relatively insensitive to potentially confounding variables like basin area. Data utilized in the analysis included gauged flow and benthic macroinvertebrate data collected at 16 locations in 11 King County stream basins. Fifteen hydrologic metrics were calculated from daily average flow data and the Pacific Northwest Benthic Index of Biological Integrity (B-IBI) was used to represent the gradient of response of stream macroinvertebrates to urbanization. Urbanization was represented by percent Total Impervious Area (%TIA) and percent urban land cover (%Urban). We found eight hydrologic metrics that were significantly correlated with B-IBI scores (Low Pulse Count and Duration; High Pulse Count, Duration, and Range; Flow Reversals, TQmean, and R-B Index). Although there appeared to be a great deal of redundancy among these metrics with respect to their response to urbanization, only two of the metrics tested – High Pulse Count and High Pulse Range – best met all four criteria we established for selecting hydrologic indicators. The increase in these high pulse metrics with respect to urbanization is the result of an increase in winter high pulses and the occurrence of high pulse events during summer (increasing the frequency and range of high pulses), when practically none would have occurred prior to development. We performed an initial evaluation of the usefulness of our hydrologic indicators by

  19. Structural characterization of Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} as a function of temperature using neutron powder diffraction and extended X-ray absorption fine structure techniques

    SciTech Connect

    Mansour, A. N.; Wong-Ng, W.; Huang, Q.; Tang, W.; Thompson, A.; Sharp, J.

    2014-08-28

    The structure of Bi{sub 2}Te{sub 3} (Seebeck coefficient Standard Reference Material (SRM™ 3451)) and the related phase Sb{sub 2}Te{sub 3} have been characterized as a function of temperature using the neutron powder diffraction (NPD) and the extended X-ray absorption fine structure (EXAFS) techniques. The neutron structural studies were carried out from 20 K to 300 K for Bi{sub 2}Te{sub 3} and from 10 K to 298 K for Sb{sub 2}Te{sub 3}. The EXAFS technique for studying the local structure of the two compounds was conducted from 19 K to 298 K. Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} are isostructural, with a space group of R3{sup ¯}m. The structure consists of repeated quintuple layers of atoms, Te2-M-Te1-M-Te2 (where M = Bi or Sb) stacking along the c-axis of the unit cell. EXAFS was used to examine the bond distances and static and thermal disorders for the first three shells of Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3} as a function of temperature. The temperature dependencies of thermal disorders were analyzed using the Debye and Einstein models for lattice vibrations. The Debye and Einstein temperatures for the first two shells of Bi{sub 2}Te{sub 3} are similar to those of Sb{sub 2}Te{sub 3} within the uncertainty in the data. However, the Debye and Einstein temperatures for the third shell of Bi-Bi are significantly lower than those of the third shell of Sb-Sb. The Einstein temperature for the third shell is consistent with a soft phonon mode in both Bi{sub 2}Te{sub 3} and Sb{sub 2}Te{sub 3}. The lower Einstein temperature of Bi-Bi relative to Sb-Sb is consistent with the lower value of thermal conductivity of Bi{sub 2}Te{sub 3} relative to Sb{sub 2}Te{sub 3}.

  20. Linking Hydrologic Alteration to Biological Impairment in Urbanizing Streams of the Puget Lowland, Washington, USA.

    PubMed

    Degasperi, Curtis L; Berge, Hans B; Whiting, Kelly R; Burkey, Jeff J; Cassin, Jan L; Fuerstenberg, Robert R

    2009-04-01

    We used a retrospective approach to identify hydrologic metrics with the greatest potential for ecological relevance for use as resource management tools (i.e., hydrologic indicators) in rapidly urbanizing basins of the Puget Lowland. We proposed four criteria for identifying useful hydrologic indicators: (1) sensitive to urbanization consistent with expected hydrologic response, (2) demonstrate statistically significant trends in urbanizing basins (and not in undeveloped basins), (3) be correlated with measures of biological response to urbanization, and (4) be relatively insensitive to potentially confounding variables like basin area. Data utilized in the analysis included gauged flow and benthic macroinvertebrate data collected at 16 locations in 11 King County stream basins. Fifteen hydrologic metrics were calculated from daily average flow data and the Pacific Northwest Benthic Index of Biological Integrity (B-IBI) was used to represent the gradient of response of stream macroinvertebrates to urbanization. Urbanization was represented by percent Total Impervious Area (%TIA) and percent urban land cover (%Urban). We found eight hydrologic metrics that were significantly correlated with B-IBI scores (Low Pulse Count and Duration; High Pulse Count, Duration, and Range; Flow Reversals, T(Qmean), and R-B Index). Although there appeared to be a great deal of redundancy among these metrics with respect to their response to urbanization, only two of the metrics tested - High Pulse Count and High Pulse Range - best met all four criteria we established for selecting hydrologic indicators. The increase in these high pulse metrics with respect to urbanization is the result of an increase in winter high pulses and the occurrence of high pulse events during summer (increasing the frequency and range of high pulses), when practically none would have occurred prior to development. We performed an initial evaluation of the usefulness of our hydrologic indicators by

  1. Bi2O3 cocatalyst improving photocatalytic hydrogen evolution performance of TiO2

    NASA Astrophysics Data System (ADS)

    Xu, Difa; Hai, Yang; Zhang, Xiangchao; Zhang, Shiying; He, Rongan

    2017-04-01

    Photocatalytic hydrogen production using water splitting is of potential importance from the viewpoint of renewable energy development. Herein, Bi2O3-TiO2 composite photocatalysts presented as Bi-Bi2O3-anatase-rutile TiO2 multijunction were first fabricated by a simple impregnation-calcination method using Bi2O3 as H2-production cocatalysts. The obtained multijunction samples exhibit an obvious enhancement in photocatalytic H2 evolution activity in the presence of glycerol. The effect of Bi2O3 amount on H2-evolution activity of TiO2 was investigated and the optimal Bi2O3 content was found to be 0.89 mol%, achieving a H2-production rate of 920 μmol h-1, exceeding that of pure TiO2 by more than 73 times. The enhanced mechanism of photocatalytic H2-evolution activity is proposed. This study will provide new insight into the design and fabrication of TiO2-based hydrogen-production photocatalysts using low-cost Bi2O3 as cocatalyst.

  2. Kinetic mechanisms of the A and B isozymes of O-acetylserine sulfhydrylase from Salmonella typhimurium LT-2 using the natural and alternative reactants.

    PubMed

    Tai, C H; Nalabolu, S R; Jacobson, T M; Minter, D E; Cook, P F

    1993-06-29

    The resonance-stabilized quinonoid 5-mercapto-2-nitrobenzoate (TNB) is a substrate for O-acetylserine sulfhydrylase-A (OASS-A) and -B (OASS-B), giving rise to the product S-(3-carboxy-4-nitrophenyl)-L-cysteine (S-CNP-cysteine) as confirmed by ultraviolet-visible and 1H NMR spectroscopies. A comparison of the kinetics of OASS-A and OASS-B indicates that the mechanism proceeds predominantly via a bi-bi ping pong kinetic mechanism as suggested by an initial velocity pattern consisting of parallel lines at low concentrations of reactants, but competitive inhibition by both substrates as the reactant concentrations are increased. Thus, in the first half-reaction, O-acetyl-L-serine (OAS) or beta-chloro-L-alanine (BCA) is converted to alpha-aminoacrylate in Schiff base with the active site pyridoxal 5'-phosphate, while in the second half-reaction cysteine (with sulfide as the reactant) or S-CNP-cysteine (with TNB as the reactant) is formed. The ping pong mechanism is corroborated by a qualitative and quantitative analysis of product and dead-end inhibition. Product inhibition by acetate is S-parabolic noncompetitive. These data are consistent with acetate reversing the first half-reaction and producing more free enzyme to which acetate may also bind. Thus, there may be some randomness to the mechanism at high concentrations of the nucleophilic substrate.

  3. Kinetics and Regulation of Mammalian NADH-Ubiquinone Oxidoreductase (Complex I)

    PubMed Central

    Chen, Xuewen; Qi, Feng; Dash, Ranjan K.; Beard, Daniel A.

    2010-01-01

    NADH-ubiquinone oxidoreductase (Complex I, European Commission No. 1.6.5.3) is one of the respiratory complexes that generate the proton-motive force required for the synthesis of ATP in mitochondria. The catalytic mechanism of Complex I has not been well understood, due to the complicated structure of this enzyme. Here, we develop a kinetic model for Complex I that accounts for electron transfer from NADH to ubiquinone through protein-bound prosthetic groups, which is coupled to the translocation of protons across the inner mitochondrial membrane. The model is derived based on the tri-bi enzyme mechanism combined with a simple model of the conformational changes associated with proton transport. To study the catalytic mechanism, parameter values are estimated by analyzing kinetic data. The model is further validated by independent data sets from additional experiments, effectively explaining the effect of pH on enzyme activity. Results imply that matrix pH significantly affects the enzyme turnover processes. The overall kinetic analysis demonstrates a hybrid ping-pong rapid-equilibrium random bi-bi mechanism, consolidating the characteristics from previously reported kinetic mechanisms and data. PMID:20816054

  4. Crystal structure and kinetic mechanism of aminoglycoside phosphotransferase-2″-IVa

    PubMed Central

    Toth, Marta; Frase, Hilary; Antunes, Nuno Tiago; Smith, Clyde A; Vakulenko, Sergei B

    2010-01-01

    Acquired resistance to aminoglycoside antibiotics primarily results from deactivation by three families of aminoglycoside-modifying enzymes. Here, we report the kinetic mechanism and structure of the aminoglycoside phosphotransferase 2″-IVa (APH(2″)-IVa), an enzyme responsible for resistance to aminoglycoside antibiotics in clinical enterococcal and staphylococcal isolates. The enzyme operates via a Bi-Bi sequential mechanism in which the two substrates (ATP or GTP and an aminoglycoside) bind in a random manner. The APH(2″)-IVa enzyme phosphorylates various 4,6-disubstituted aminoglycoside antibiotics with catalytic efficiencies (kcat/Km) of 1.5 × 103 to 1.2 × 106 (M−1 s−1). The enzyme uses both ATP and GTP as the phosphate source, an extremely rare occurrence in the phosphotransferase and protein kinase enzymes. Based on an analysis of the APH(2″)-IVa structure, two overlapping binding templates specifically tuned for hydrogen bonding to either ATP or GTP have been identified and described. A detailed understanding of the structure and mechanism of the GTP-utilizing phosphotransferases is crucial for the development of either novel aminoglycosides or, more importantly, GTP-based enzyme inhibitors which would not be expected to interfere with crucial ATP-dependent enzymes. PMID:20556826

  5. Microwave Assisted Enzymatic Kinetic Resolution of (±)-1-Phenyl-2-propyn-1-ol in Nonaqueous Media

    PubMed Central

    Devendran, Saravanan; Yadav, Ganapati D.

    2014-01-01

    Kinetic resolution of 1-phenyl-2-propyn-1-ol, an important chiral synthon, was studied through trans-esterification with acyl acetate to investigate synergism between microwave irradiation and enzyme catalysis. Lipases from different microbial origins were employed for the kinetic resolution of (R/S)-1-phenyl-2-propyn-1-ol, among which Candida antarctica lipase B, immobilized on acrylic resin (Novozym 435), was found to be the best catalyst in n-hexane as solvent. Vinyl acetate was the most effective among different acyl esters studied. The effect of various parameters was studied in a systematic manner. Definite synergism between microwave and enzyme was observed. The initial rate was improved around 1.28 times under microwave irradiation than conventional heating. Under optimum conditions, maximum conversion (48.78%) and high enantiomeric excess (93.25%) were obtained in 2 h. From modeling studies, it is concluded that the reaction follows the Ping-Pong bi-bi mechanism with dead end alcohol inhibition. Kinetic parameters were obtained by using nonlinear regression. This process is green, clean, and easily scalable as compared to the chemical process. PMID:24707487

  6. A kinetic study on the Novozyme 435-catalyzed esterification of free fatty acids with octanol to produce octyl esters.

    PubMed

    Chowdhury, Avisha; Mitra, Debarati

    2015-01-01

    Octyl esters can serve as an important class of biolubricant components replacing their mineral oil counterparts. The purpose of the current work was to investigate the enzymatic esterification reaction of free fatty acids (FFA, from waste cooking oil) with octanol in a solvent-free system using a commercial lipase Novozyme 435. It was found that the esterificaton reaction followed the Ping-pong bi-bi kinetics with no inhibition by substrates or products within the studied concentration range. The maximum reaction rate was estimated to be 0.041 mol L(-1) g(-1) h(-1) . Additionally, the stability of Novozyme 435 in the current reaction system was studied by determining its activity and final conversion of FFA to esters after 12 successive utilizations. Novozyme 435 exhibited almost 100% enzyme activity up to 7 cycles of reaction and gradually decreased (by 5%) thereafter. The kinetic parameters evaluated from the study shall assist in the design of reactors for large-scale production of octyl esters from a cheap biomass source. The enzyme reusability data can further facilitate mass production by curtailing the cost of expensive enzyme consumption.

  7. Kinetic modeling and docking study of immobilized lipase catalyzed synthesis of furfuryl acetate.

    PubMed

    Mathpati, Ashwini C; Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

    2016-03-01

    The present work deals with the kinetic modeling and docking study for the furfuryl acetate synthesis using immobilized Burkholderia cepacia (BCL) lipase. Initially various lipases were immobilized on hydroxypropyl methyl cellulose (HPMC) and poly vinyl alcohol (PVA) base hybrid polymer matrix. After screening of various immobilized biocatalysts, HPMC:PVA:BCL was found to be a robust biocatalyst. Various reaction conditions were optimized using response surface methodology (RSM) based on a four-factor-three-level Box-Behnken design. The optimal conditions were obtained at molar ratio of 1:2 of furfuryl alcohol to acyl donor, temperature 50°C with catalyst loading of 30mg in 3mL of non-aqueous media toluene. Under these conditions 99.98% yield was obtained in 3h. The Arrhenius plot showed that the activation energy for furfuryl acetate synthesis was 10.68kcal/mol. The kinetics of reaction was studied close to optimized conditions which obey order bi-bi model. Molecular docking study was carried out to understand the active site of BCL which is responsible for the reaction. It was observed that the reaction proceeds via acylation of the active serine of BCL and demonstrating strong hydrogen bond between the substrate and histidine site. The catalyst recyclability study was carried up to five cycles.

  8. Unraveling the B. pseudomallei Heptokinase WcbL: From Structure to Drug Discovery

    PubMed Central

    Vivoli, Mirella; Isupov, Michail N.; Nicholas, Rebecca; Hill, Andrew; Scott, Andrew E.; Kosma, Paul; Prior, Joann L.; Harmer, Nicholas J.

    2015-01-01

    Summary Gram-negative bacteria utilize heptoses as part of their repertoire of extracellular polysaccharide virulence determinants. Disruption of heptose biosynthesis offers an attractive target for novel antimicrobials. A critical step in the synthesis of heptoses is their 1-O phosphorylation, mediated by kinases such as HldE or WcbL. Here, we present the structure of WcbL from Burkholderia pseudomallei. We report that WcbL operates through a sequential ordered Bi-Bi mechanism, loading the heptose first and then ATP. We show that dimeric WcbL binds ATP anti-cooperatively in the absence of heptose, and cooperatively in its presence. Modeling of WcbL suggests that heptose binding causes an elegant switch in the hydrogen-bonding network, facilitating the binding of a second ATP molecule. Finally, we screened a library of drug-like fragments, identifying hits that potently inhibit WcbL. Our results provide a novel mechanism for control of substrate binding and emphasize WcbL as an attractive anti-microbial target for Gram-negative bacteria. PMID:26687481

  9. Impact of storm-water outfalls on sediment quallity in corpus Christi Bay, Texas, USA

    USGS Publications Warehouse

    Carr, R. Scott; Montagna, Paul A.; Biedenbach, James M.; Kalke, Rick; Kennicutt, Mahlon C.; Hooten, Russell L.; Cripe, Geraldine

    2000-01-01

    To determine the quality of sediments and extent of contaminant impacts, a Sediment Quality Triad (SQT) study was conducted at 36 sites in the Corpus Christi Bay, Texas, USA, system. Fifteen of the 36 sites were located near storm-water outfalls, but 13 other sites (i.e., industrial and domestic outfalls, oil field–produced water discharges, and dredging activity) and eight reference sites were also evaluated. Sediment samples were collected and analyzed for physical–chemical characteristics, contaminant concentrations (metals, polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], and pesticides), toxicity (amphipod and mysid solid phase and sea urchin pore-water fertilization and embryological development tests), and a benthic index of biotic integrity (BIBI) composed of 10 independent metrics calculated for each site. This large data matrix was reduced using multivariate analysis to create new variables for each component representing overall means and containing most of the variance in the larger data set. The new variables were used to conduct the correlation analysis. Toxicity was significantly correlated with both chemistry and ecological responses, whereas no correlations between the benthic metrics and sediment chemistry were observed. Using the combined information from the SQT, four of the five most degraded sites were storm-water outfall sites. Although estuaries are naturally stressful environments because of salinity and temperature fluctuations, this ecosystem appears to have been compromised by anthropogenic influences similar to what has been observed for other heavily urbanized bay systems along the Texas and Gulf coast.

  10. Catalase-like activity of bovine met-hemoglobin: interaction with the pseudo-catalytic peroxidation of anthracene traces in aqueous medium.

    PubMed

    Paco, Laveille; Galarneau, Anne; Drone, Jullien; Fajula, François; Bailly, Carole; Pulvin, Sylviane; Thomas, Daniel

    2009-10-01

    Hemoglobin is a member of the hemoprotein superfamily whose main role is to transport O(2) in vertebrate organisms. It has two known promiscuous enzymatic activities, peroxidase and oxygenase. Here we show for the first time that bovine hemoglobin also presents a catalase-like activity characterized by a V(max )of 344 microM/min, a K(M )of 24 mM and a k(cat) equal to 115/min. For high anthracene and hemoglobin concentrations and low hydrogen peroxide concentrations, this activity inhibits the expected oxidation of anthracene, which occurs through a peroxidase-like mechanism. Anthracene belongs to the polycyclic aromatic hydrocarbon (PAH) family whose members are carcinogenic and persistent pollutants found in industrial waste waters. Our results show that anthracene oxidation by hemoglobin and hydrogen peroxide follows a typical bi-bi ping-pong mechanism with a V(max) equal to 0.250 microM/min, K(M(H2O2) )of 80 microM, K(M(ANT)) of 1.1 microM and k(cat) of 0.17/min. The oxidation of anthracene is shown to be pseudo-catalytic because an excess of hemoglobin and hydrogen peroxide is required to make PAH completely disappear. Thus, bovine hemoglobin presents, in different degrees, all the catalytic activities of the hemoprotein group, which makes it a very interesting protein for biotechnological processes and one with which structure-activity relationships can be studied.

  11. Lipase-catalyzed kinetic resolution of (±)-1-(2-furyl) ethanol in nonaqueous media.

    PubMed

    Devendran, Saravanan; Yadav, Ganapati D

    2014-06-01

    S-1-(2-Furyl) ethanol serves as an important chiral building block for the preparation of various natural products, fine chemicals, and is widely used in the chemical and pharmaceutical industries. In this work, lipase-catalyzed kinetic resolution of (R/S)-1-(2-furyl) ethanol using different acyl donors was investigated. Vinyl esters are good acyl donors vis-à-vis alkyl esters for kinetic resolution. Among them, vinyl acetate was found to be the best acyl donor. Different immobilized lipases such as Rhizomucor miehei lipase, Thermomyces lanuginosus lipase, and Candida antarctica lipase B were evaluated for this reaction, among which C. antarctica lipase B, immobilized on acrylic resin (Novozym 435), was found to be the best catalyst in n-heptane as solvent. The effect of various parameters was studied in a systematic manner. Maximum conversion of 47% and enantiomeric excess of the substrate (ees ) of 89% were obtained in 2 h using 5 mg of enzyme loading with an equimolar ratio of alcohol to vinyl acetate at 60 °C at a speed of 300 rpm in a batch reactor. From the analysis of progress curve and initial rate data, it was concluded that the reaction followed the ordered bi-bi mechanism with dead-end ester inhibition. Kinetic parameters were obtained by using nonlinear regression. This process is more economical, green, and easily scalable than the chemical processes. © 2014 Wiley Periodicals, Inc.

  12. Electronic Structure of CsBi(4 )Te(6 ): A New Low Temperature Thermoelectric

    NASA Astrophysics Data System (ADS)

    Larson, P.; Mahanti, S. D.; Chung, D.-Y.; Kanatzidis, M. G.

    2001-03-01

    Recently, it has been found that CsBi(4 )Te( 6 ) is a narrow-gap semiconductor with a larger thermoelectric figure of merit (ZT ( ~ ) 0.8) than traditional Bi(_2-x )Sb(x )Te(3 ) alloys at low temperatures (T < 225 K).(D-Y Chung, T. Hogan, P. Brazis, M. Rocci-Lane, C. Kannewurf, M. Bastea, C. Uher, M.G. Kanatzidis, Science 287), 1024 (2000). This improvement has been seen in the hole-doped samples. Since thermoelectric properties depend sensitively on the electronic structure of these narrow gap semiconductors, we have carried out detailed electronic structure calculations of CsBi(4 )Te(6 ) using ab initio all-electron linearized-augmented planewave (LAPW) method within density functional theory (DFT). The crystal structure of CsBi(4 )Te( 6 ) contains Bi-Bi bonds, unique for chalcogenide systems, which we find to play an important role in its electronic structure and thermoelectric properties. The predicted hole transport in this system is highly anisotropic and counterintuitive. Implications of our electronic structure calculations on the thermoelectric properties will be discussed.

  13. Bi2(C2O4)3·7H2O and Bi(C2O4)OH Oxalates Thermal Decomposition Revisited. Formation of Nanoparticles with a Lower Melting Point than Bulk Bismuth.

    PubMed

    Roumanille, Pierre; Baco-Carles, Valérie; Bonningue, Corine; Gougeon, Michel; Duployer, Benjamin; Monfraix, Philippe; Le Trong, Hoa; Tailhades, Philippe

    2017-08-21

    Two bismuth oxalates, namely, Bi2(C2O4)3·7H2O and Bi(C2O4)OH, were studied in terms of synthesis, structural characterization, particle morphology, and thermal behavior under several atmospheres. The oxalate powders were produced by chemical precipitation from bismuth nitrate and oxalic acid solutions under controlled pH, then characterized by X-ray diffraction (XRD), temperature-dependent XRD, IR spectroscopy, scanning electron microscopy, and thermogravimetric differential thermal analyses. New results on the thermal decomposition of bismuth oxalates under inert or reducing atmospheres are provided. On heating in nitrogen, both studied compounds decompose into small bismuth particles. Thermal properties of the metallic products were investigated. The Bi(C2O4)OH decomposition leads to a Bi-Bi2O3 metal-oxide composite product in which bismuth is confined in a nanometric size, due to surface oxidation. The melting point of such bismuth particles is strongly related to their crystallite size. The nanometric bismuth melting has thus been evidenced ∼40 °C lower than for bulk bismuth. These results should contribute to the development of the oxalate precursor route for low-temperature soldering applications.

  14. Biochemical characterization of NfsA, the Escherichia coli major nitroreductase exhibiting a high amino acid sequence homology to Frp, a Vibrio harveyi flavin oxidoreductase.

    PubMed Central

    Zenno, S; Koike, H; Kumar, A N; Jayaraman, R; Tanokura, M; Saigo, K

    1996-01-01

    We identified the nfsA gene, encoding the major oxygen-insensitive nitroreductase in Escherichia coli, and determined its position on the E. coli map to be 19 min. We also purified its gene product, NfsA, to homogeneity. It was suggested that NfsA is a nonglobular protein with a molecular weight of 26,799 and is associated tightly with a flavin mononucleotide. Its amino acid sequence is highly similar to that of Frp, a flavin oxidoreductase from Vibrio harveyi (B. Lei, M. Liu, S. Huang, and S.-C. Tu, J. Bacteriol. 176:3552-3558, 1994), an observation supporting the notion that E. coli nitroreductase and luminescent-bacterium flavin reductase families are intimately related in evolution. Although no appreciable sequence similarity was detected between two E. coli nitroreductases, NfsA and NfsB, NfsA exhibited a low level of the flavin reductase activity and a broad electron acceptor specificity similar to those of NfsB. NfsA reduced nitrofurazone by a ping-pong Bi-Bi mechanism possibly to generate a two-electron transfer product. PMID:8755878

  15. The kinetic mechanism of Human Thymidine Phosphorylase - a molecular target for cancer drug development.

    PubMed

    Deves, Candida; Rostirolla, Diana Carolina; Martinelli, Leonardo Kras Borges; Bizarro, Cristiano Valim; Santos, Diogenes Santiago; Basso, Luiz Augusto

    2014-03-04

    Human Thymidine Phosphorylase (HTP), also known as the platelet-derived endothelial cell growth factor (PD-ECGF) or gliostatin, catalyzes the reversible phosphorolysis of thymidine (dThd) to thymine and 2-deoxy-α-d-ribose-1-phosphate (2dR1P). HTP is a key enzyme in the pyrimidine salvage pathway involved in dThd homeostasis in cells. HTP is a target for anticancer drug development as its enzymatic activity promotes angiogenesis. Here, we describe cloning, expression, and purification to homogeneity of recombinant TYMP-encoded HTP. Peptide fingerprinting and the molecular mass value of the homogenous protein confirmed its identity as HTP assessed by mass spectrometry. Size exclusion chromatography showed that HTP is a dimer in solution. Kinetic studies revealed that HTP displayed substrate inhibition for dThd. Initial velocity and isothermal titration calorimetry (ITC) studies suggest that HTP catalysis follows a rapid-equilibrium random bi-bi kinetic mechanism. ITC measurements also showed that dThd and Pi binding are favorable processes. The pH-rate profiles indicated that maximal enzyme activity was achieved at low pH values. Functional groups with apparent pK values of 5.2 and 9.0 are involved in dThd binding and groups with pK values of 6.1 and 7.8 are involved in phosphate binding.

  16. Laser filamentation in (E\\vert \\vert B) standing EM waves

    NASA Astrophysics Data System (ADS)

    Alouani Bibi, Fathallah; Matte, Jean-Pierre; Brabec, Thomas; Corkum, Paul

    2004-11-01

    Theoretical analyses [1] and experiment [2] have shown that standing wave solutions to Maxwell's equations with E\\vert \\vert B can be generated with two counter-propagating beams. We analyze the effects of such a wave on laser heating of under-dense plasmas, and filamentation. In ordinary beams, ponderomotive effects dominate at high intensity and thermal ones at low intensity [3]. If the intensity of this E\\vert \\vert B field can be modulated in the direction perpendicular to the propagation axis and to the fields, filamentation, should then be dominated by thermal effects, even at high intensity, because the ponderomotive force would then nearly cancel. This would allow the study of the effect of high intensity radiation on thermal transport, which was predicted to be important [4]. [1] C. Chu and T. Okhawa, Phys. Rev. Lett. 48, 837 (1982); N. Milosevic, P. B. Corkum, and T. Brabec, ibid., 92, 013002 (2004). [2] F. Bretenaker and A.Le. Floch, Phys. Rev. A 43, 3704 (1991). [3] P.E. Young, Phys. Plasmas 2, 2815 (1995). [4] F. Alouani Bibi and J.-P. Matte, Phys. Rev. E 66 (2002) 066414..

  17. Hydrodynamic and Fokker-Planck simulations of electron transport in plasmas

    NASA Astrophysics Data System (ADS)

    Alouani Bibi, Fathallah; Matte, Jean-Pierre; Braun, David G.; Edwards, M. John; Suter, Laurence J.

    2004-03-01

    Kinetic and hydrodynamic simulations of plasma dynamics are performed for different plasma regimes, with steep gradients. Temperatures ranged from 1 eV to 10 keV, densities from 10^14cm-3 to 10^23cm-3 and a variety of plasma materials were considered (Hydrogen, Beryllium, Carbon, Aluminum and Vanadium). The effect of laser heating of the plasma is analyzed, with laser pulse durations from 0.1 to 1 ns and intensities from 10^10 to 10^16 W/cm^2. The effect of the wave length (1.06, 0.53 and 0.35 μ m) on absorption is also discussed. Limitations to usual hydrodynamic models such as nonlocal effects and non Maxwellian electron distribution function due to steep temperature gradients and strong laser heating are stressed and we show how our nonlocal model [1] can extend the hydrodynamic description to such regimes. [1] F. Alouani Bibi and J.P. Matte, Phys. Rev. E 66, 066414 (2002).

  18. Assessing Pb,Zn,Cd contamination in stream sediments of south east Tehran (Iran)

    NASA Astrophysics Data System (ADS)

    Shahdadi, S.; Fayazi, F.; Yaghoobpour, A.; Rahmani, F.; Moslempour, M.

    2009-04-01

    Assessing Pb,Zn,Cd contamination in stream sediments of south east Tehran (Iran) 31 sediment samples collected from south east of Tehran around cement plant (Bibi shahrbanoo mountain) were analyzed by ICP for Pb, Zn, Cd. The samples were also investigated for mineralogy using X-ray analysis.The clay mineral assemblage encountered in the analyzed samples is composed of vermiculite, dickite, montmorillonite and kaolinite.The non-clay minerals of the mud-sized fraction are composed mainly of quartz and calcite and dolomite as major minerals with albite, hematite, muscovite as minor minerals. The measured metals correlated positively with the determined physiochemical factors such as pH, clay content, organic matter content, and carbonate content. According to the index of geoaccumulation, the sediments of the study area are considered to be strongly to very strongly polluted with respect to Pb, strongly polluted with respect to Zn, and moderatly to strongly polluted with recpect to Cd.The calculation of enrichment factors shows that the source of Pb and Zn is from antropogenic activites such as cement plant and vehicle exhausts and Cd from natural source.

  19. Kinetic effects on parallel heat flow and ionization rate in divertor plasmas

    NASA Astrophysics Data System (ADS)

    Allais, Fabrice; Kim, Chang-Geun; Alouani Bibi, Fathallah; Matte, Jean-Pierre; Stotler, Daren; Rognlien, Thomas

    2004-11-01

    1-D simulations of parallel heat flow in divertor plasmas, with and without recycling are made with the UEDGE fluid code, comparing runs using classical flux limited heat flow to nonlocal heat transport [1], now implemented in UEDGE. Comparative simulations are made with the electron kinetic code FPI. For the latter, we prescribe the power input source, which emulates cross field transport, to be identical to that of our UEDGE runs. But, the temperature profile computed by FPI is found to depend very strongly on the assumed velocity dependence of this source, even if the integrated power is the same. The atomic hydrogen ionization module in FPI uses cross sections such that, for Maxwellian plasmas, the rates are the same as those used by UEDGE and DEGAS; this is necessary because step-wise ionization is dominant. There is strong enhancement of the total ionization rate (including stepwise ionization) in cold, detached plasmas, due to nonlocal transport effects. [1] F. Alouani Bibi and J.P. Matte, Phys. Rev. E 66, 066414 (2002)

  20. The role of anisotropic target electrons for e-e collisions in hot electron transport in dense matter

    NASA Astrophysics Data System (ADS)

    Matte, Jean-Pierre; Alouani Bibi, Fathallah; Shoucri, Magdi

    2004-11-01

    The transport of hot electrons (TH = 20-40 keV) generated by an ultra-short (FWHM = 0.1 to 1.2 ps) high intensity (I =10^16 to 10^19 W/cm^2) laser pulse and their interaction with cold solid density aluminium plasma is simulated. The anisotropy of the electron-electron collision operator has been added by using the semi-anisotropic Rosenbluth potentials approximation in our Fokker-Planck operator [1] in our improved electron kinetic code ``FPI+'' [2]. The resistivity of the thermal plasma is investigated, and compared to Spitzer conductivity, and to simpler collision operators (Lorentz gas, isotropic Rosenbluth potentials). Atomic physics (ionization etc. , with an average ion model fully coupled to the free electrons' velocity distribution) and energy exchange between electrons and ions are included. [1] I.P.Shkarofsky, M.M. Shoucri and V.Fuchs, Computer Phys. Comm. 71, 269 (1992). [2] F. Alouani Bibi, M.M. Shoucri,and ^ J-P. Matte, ibid., to be published (2004)

  1. Origin of the Bismuth-Induced Decohesion of Nickel and Copper Grain Boundaries

    NASA Astrophysics Data System (ADS)

    Kang, Joongoo; Glatzmaier, Greg C.; Wei, Su-Huai

    2013-08-01

    Ductile metals such as Ni and Cu can become brittle when certain impurities (e.g., Bi) diffuse and segregate into their grain boundaries (GBs). Using first-principles calculations, we investigate the microscopic origin of the Bi-induced loss of cohesion of Ni and Cu GBs. We find that the Bi bilayer interfacial phase is the most stable impurity phase under the Bi-rich condition, while the Bi monolayer phase is a metastable phase regardless of the value of the Bi chemical potential. Our finding is consistent with the recent experimental observation for Ni GBs [Luo et al. Science 333, 1730 (2011)SCIEAS0036-807510.1126/science.1208774]. The electric polarization effect of the Bi bilayer substantially enhances the strength of the Bi-metal interfacial bonds, stabilizing the bilayer phase over other phases. The Bi-Bi interlayer bonding is significantly weakened in the GBs, leading to a factor of 20 to 50 decrease in the GB cohesion, which has strong implications for the understanding of Bi-induced intergranular fracture of Ni and Cu polycrystals.

  2. Unraveling the B. pseudomallei Heptokinase WcbL: From Structure to Drug Discovery.

    PubMed

    Vivoli, Mirella; Isupov, Michail N; Nicholas, Rebecca; Hill, Andrew; Scott, Andrew E; Kosma, Paul; Prior, Joann L; Harmer, Nicholas J

    2015-12-17

    Gram-negative bacteria utilize heptoses as part of their repertoire of extracellular polysaccharide virulence determinants. Disruption of heptose biosynthesis offers an attractive target for novel antimicrobials. A critical step in the synthesis of heptoses is their 1-O phosphorylation, mediated by kinases such as HldE or WcbL. Here, we present the structure of WcbL from Burkholderia pseudomallei. We report that WcbL operates through a sequential ordered Bi-Bi mechanism, loading the heptose first and then ATP. We show that dimeric WcbL binds ATP anti-cooperatively in the absence of heptose, and cooperatively in its presence. Modeling of WcbL suggests that heptose binding causes an elegant switch in the hydrogen-bonding network, facilitating the binding of a second ATP molecule. Finally, we screened a library of drug-like fragments, identifying hits that potently inhibit WcbL. Our results provide a novel mechanism for control of substrate binding and emphasize WcbL as an attractive anti-microbial target for Gram-negative bacteria.

  3. Impact of storm-water outfalls on sediment quality in Corpus Christi Bay, Texas, USA

    SciTech Connect

    Carr, R.S.; Montagna, P.A.; Biedenbach, J.M.; Kalke, R.; Kennicutt, M.C.; Hooten, R.; Cripe, G.

    2000-03-01

    To determine the quality of sediments and extent of contaminant impacts, a Sediment Quality Triad (SQT) study was conducted at 36 sites in the Corpus Christi Bay, Texas, USA, system. Fifteen of the 36 sites were located near storm-water outfalls, but 13 other sites (i.e., industrial and domestic outfalls, oil field-produced water discharges, and dredging activity) and eight reference sites were also evaluated. Sediment samples were collected and analyzed for physical-chemical characteristics, contaminant concentrations (metals, polycyclic aromatic hydrocarbons [PAHs], polychlorinated biphenyls [PCBs], and pesticides), toxicity, and a benthic index of biotic integrity (BIBI) composed of 10 independent metrics calculated for each site. This large data matrix was reduced using multivariate analysis to create new variables for each component representing overall means and containing most of the variance in the larger data set. The new variables were used to conduct the correlation analysis. Toxicity was significantly correlated with both chemistry and ecological responses, whereas no correlations between the benthic metrics and sediment chemistry were observed. Using the combined information from the SQT, four of the five most degraded sites were storm-water outfall sites. Although estuaries are naturally stressful environments because of salinity and temperature fluctuations, this ecosystem appears to have been compromised by anthropogenic influences similar to what has been observed for other heavily urbanized bay systems along the Texas and Gulf coast.

  4. Evolution of Enzyme Kinetic Mechanisms.

    PubMed

    Ulusu, Nuriye Nuray

    2015-06-01

    This review paper discusses the reciprocal kinetic behaviours of enzymes and the evolution of structure-function dichotomy. Kinetic mechanisms have evolved in response to alterations in ecological and metabolic conditions. The kinetic mechanisms of single-substrate mono-substrate enzyme reactions are easier to understand and much simpler than those of bi-bi substrate enzyme reactions. The increasing complexities of kinetic mechanisms, as well as the increasing number of enzyme subunits, can be used to shed light on the evolution of kinetic mechanisms. Enzymes with heterogeneous kinetic mechanisms attempt to achieve specific products to subsist. In many organisms, kinetic mechanisms have evolved to aid survival in response to changing environmental factors. Enzyme promiscuity is defined as adaptation to changing environmental conditions, such as the introduction of a toxin or a new carbon source. Enzyme promiscuity is defined as adaptation to changing environmental conditions, such as the introduction of a toxin or a new carbon source. Enzymes with broad substrate specificity and promiscuous properties are believed to be more evolved than single-substrate enzymes. This group of enzymes can adapt to changing environmental substrate conditions and adjust catalysing mechanisms according to the substrate's properties, and their kinetic mechanisms have evolved in response to substrate variability.

  5. Crystal growth, complex phase diagram and high pressure studies of layer compound PdBi2

    NASA Astrophysics Data System (ADS)

    Zhao, Kui; Zhu, Xiyu; Lv, Bing; Xue, Yuyi; Chu, Paul

    2013-03-01

    Among the different Pd-Bi Alloys, β-PdBi2, which is crystallized in a layered tetragonal (I4/mmm) structure, has been identified as a superconductor with transition temperature at ~ 5.4K. Band structure calculation indicates that the interlayer Bi-Bi bonds are weak but not negligible, which implies the 3D bonding character of this compound. In order to enhance or weaken the interlayer bonding and ultimately increase the Tc in this system, high pressure measurement, isovalent chemical substitution of Bi with Sb, and chemical intercalation using transition metal Cu and alkali metal Na, are applied to the system. Meanwhile, aliovalent chemical substitution on the Bi site by Pb is also carried out. The magnetic, electrical, and calorimetric properties of these compounds are determined at ambient pressure and compared. The detailed high pressure results and the complete phase diagram of chemical substitution and intercalation will be presented and discussed. Work in Houston is supported in part by US AFOSR, the State of Texas, T. L. L. Temple Foundation and John and Rebecca Moores Endowment.

  6. 'In situ' diagnostics of solid electrolyte sensors measuring oxygen activity in melts by a developed impedance method

    NASA Astrophysics Data System (ADS)

    Zhuiykov, Serge

    2006-06-01

    An impedance method for the periodic 'in situ' diagnostics of the solid electrolyte/liquid-metal electrode interface during the lifespan of yttria-stabilized zirconia (YSZ) based sensors measuring oxygen partial pressure in melts was developed. Polarization effects on the YSZ, resulting from the corrosive measuring environment (molten alkaline metals), may be interpreted as a blocking reaction layer on the electrolyte/liquid-metal electrode interface. The proposed impedance method allows information to be obtained about the level of polarization of the YSZ/liquid-metal electrode interface that is characterized by a second semi-arc of a hodograph of impedance. The second semi-arc represents the parameters of polarization resistance (Rf) and capacitance of the double electrical layer on the interface YSZ/liquid metal (CD). Analysis of the impedance method on the single crystal zirconia sensor measuring dissolved oxygen in molten lead at temperatures of 380-480 °C revealed that this sensor, with a Bi-Bi2O3 reference electrode, showed a negligible level of polarization effects on the electrode/electrolyte interface at temperatures as low as 380 °C. The results of the present work may be applicable for the diagnostics of oxygen sensors with more complicated applications, such as in the measurement of oxygen activity in lead-bismuth, sodium or lithium heat carriers in liquid-metal nuclear facilities.

  7. 2-O-α-D-Glucosylglycerol Phosphorylase from Bacillus selenitireducens MLS10 Possessing Hydrolytic Activity on β-D-Glucose 1-Phosphate

    PubMed Central

    Nihira, Takanori; Saito, Yuka; Ohtsubo, Ken’ichi; Nakai, Hiroyuki; Kitaoka, Motomitsu

    2014-01-01

    The glycoside hydrolase family (GH) 65 is a family of inverting phosphorylases that act on α-glucosides. A GH65 protein (Bsel_2816) from Bacillus selenitireducens MLS10 exhibited inorganic phosphate (Pi)-dependent hydrolysis of kojibiose at the rate of 0.43 s−1. No carbohydrate acted as acceptor for the reverse phosphorolysis using β-d-glucose 1-phosphate (βGlc1P) as donor. During the search for a suitable acceptor, we found that Bsel_2816 possessed hydrolytic activity on βGlc1P with a kcat of 2.8 s−1; moreover, such significant hydrolytic activity on sugar 1-phosphate had not been reported for any inverting phosphorylase. The H218O incorporation experiment and the anomeric analysis during the hydrolysis of βGlc1P revealed that the hydrolysis was due to the glucosyl-transferring reaction to a water molecule and not a phosphatase-type reaction. Glycerol was found to be the best acceptor to generate 2-O-α-d-glucosylglycerol (GG) at the rate of 180 s−1. Bsel_2816 phosphorolyzed GG through sequential Bi-Bi mechanism with a kcat of 95 s−1. We propose 2-O-α-d-glucopyranosylglycerol: phosphate β-d-glucosyltransferase as the systematic name and 2-O-α-d-glucosylglycerol phosphorylase as the short name for Bsel_2816. This is the first report describing a phosphorylase that utilizes polyols, and not carbohydrates, as suitable acceptor substrates. PMID:24466148

  8. PnrA, a new nitroreductase-family enzyme in the TNT-degrading strain Pseudomonas putida JLR11.

    PubMed

    Caballero, Antonio; Lázaro, Juan J; Ramos, Juan L; Esteve-Núñez, Abraham

    2005-08-01

    Nitroreductases are a group of proteins that catalyse pyridine nucleotide-dependent reduction of nitroaromatics compounds, showing significant human health and environmental implications. In this study we have identified the nitroreductase-family enzymes PnrA and PnrB from the TNT-degrading strain Pseudomonas putida. The enzyme encoded by the pnrA gene was expressed in Escherichia coli, purified to homogeneity and shown to be a flavoprotein that used 2 mol of NADPH to reduce 1 mol of 2,4,6-trinitrotoluene (TNT) to 4-hydroxylamine-2,6-dinitrotoluene, using a ping-pong bi-bi mechanism. The PnrA enzyme also recognized as substrates as a number of other nitroaromatic compounds, i.e. 2,4-dinitrotoluene, 3-nitrotoluene, 3- and 4-nitrobenzoate, 3,5-dinitrobenzamide and 3,5-dinitroaniline expanding the substrates profile from previously described nitroreductases. However, TNT resulted to be the most efficient substrate examined according to the Vmax/Km parameter. Expression analysis of pnrA- and pnrB-mRNA isolated from cells growing on different nitrogen sources suggested that expression of both genes was constitutive and that its level of expression was relatively constant regardless of the growth substrate. This is in agreement with enzyme-specific activity determined with cells growing with different N-sources.

  9. Application of lipase immobilized on the biocompatible ternary blend polymer matrix for synthesis of citronellyl acetate in non-aqueous media: kinetic modelling study.

    PubMed

    Badgujar, Kirtikumar C; Bhanage, Bhalchandra M

    2014-04-10

    This work reports the use of new support for immobilization of lipase Burkholderia cepacia (BCL) matrix made up of polylactic acid (PLA), chitosan (CH), and polyvinyl alcohol (PVA). Initially lipase from various microbial sources and immobilization support composition was screened to obtain a robust biocatalyst. Among various biocatalysts preparation, the PLA:PVA:CH:BCL (1:6:1:2) was worked as a robust biocatalyst for the citronellyl acetate synthesis. Various reaction parameters were studied in detail to obtain the suitable reaction conditions for model citronellyl acetate synthesis reaction. Various kinetic parameters such as r(max), K(i(citronellol)), K(m(citronellol)), K(m(vinyl acetate)) were determined using non-linear regression analysis for the ternary complex as well as bi-bi ping-pong mechanism. The experimental results and kinetic study showed that citronellyl acetate synthesis catalyzed by immobilized lipase BCL followed the ternary complex mechanism with inhibition by alcohol (citronellol). The energy of activation for citronellyl acetate synthesis was found to be lower for immobilized lipase (8.9 kcal/mol) than aggregated lipase (14.8 kcal/mol) enzyme. The developed biocatalyst showed four to fivefold higher catalytic activity and excellent recyclability (up to six cycles) than the aggregated lipase. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Evidence for Distributivity Effects in Comprehension

    PubMed Central

    Patson, Nikole D.; Warren, Tessa

    2010-01-01

    In the current paper, we introduce a new methodology for detecting whether a word in a sentence is conceptually represented as plural and use it to shed light on a debate about whether comprehenders interpret singular indefinite noun phrases within a distributed predicate as plural during on-line reading. Experiment 1 extended a methodology previously used by Berent, Pinker, Tzelgov, Bibi, and Goldfarb (2005) to test individual words or word pairs by, at a critical word, having readers judge whether one or two words appeared on a computer screen while performing self-paced reading on a sentence presented in one- and two-word chunks. Consistent with Berent et al., Experiment 1 indicated that participants were slower to judge that one word was on the screen when the word was plural (e.g., cats) than when it was singular (e.g., cat). Experiment 2 used this paradigm to show that readers build different conceptual representations for distributed versus collective predicates, and interpret a singular indefinite noun phrase within a distributed predicate as plural (e.g., Kaup, Kelter, & Habel, 2002, but cf. Filik, Paterson, & Liversedge, 2004; Paterson, Filik, & Liversedge, 2008). PMID:20438272

  11. Ferromagnetism below 10K in Mn-doped BiTe

    NASA Astrophysics Data System (ADS)

    Bos, J. W. G.; Lee, M.; Morosan, E.; Zandbergen, H. W.; Lee, W. L.; Ong, N. P.; Cava, R. J.

    2006-11-01

    Ferromagnetism is observed below 10K in [Bi0.75Te0.125Mn0.125]Te . This material has the BiTe structure, which is made from the stacking of two Te-Bi-Te-Bi-Te blocks and one Bi-Bi block per unit cell. Crystal structure analysis shows that Mn is localized in the Bi2 blocks, and is accompanied by an equal amount of TeBi antisite occupancy in the Bi2Te3 blocks. These TeBi antisite defects greatly enhance the Mn solubility. This is demonstrated by comparison of the [Bi1-xMnx]Te and [Bi1-2xTexMnx]Te series; in the former, the solubility is limited to x=0.067 , while the latter has xmax=0.125 . The magnetism in [Bi1-xMnx]Te changes little with x , while that for [Bi1-2xTexMnx]Te shows a clear variation, leading to ferromagnetism for x>0.067 . Magnetic hysteresis and the anomalous Hall effect are observed for the ferromagnetic samples.

  12. Lipase-catalyzed synthesis of palmitanilide: Kinetic model and antimicrobial activity study.

    PubMed

    Liu, Kuan-Miao; Liu, Kuan-Ju

    2016-01-01

    Enzymatic syntheses of fatty acid anilides are important owing to their wide range of industrial applications in detergents, shampoo, cosmetics, and surfactant formulations. The amidation reaction of Mucor miehei lipase Lipozyme IM20 was investigated for direct amidation of triacylglycerol in organic solvents. The process parameters (reaction temperature, substrate molar ratio, enzyme amount) were optimized to achieve the highest yield of anilide. The maximum yield of palmitanilide (88.9%) was achieved after 24 h of reaction at 40 °C at an enzyme concentration of 1.4% (70 mg). Kinetics of lipase-catalyzed amidation of aniline with tripalmitin has been investigated. The reaction rate could be described in terms of the Michaelis-Menten equation with a Ping-Pong Bi-Bi mechanism and competitive inhibition by both the substrates. The kinetic constants were estimated by using non-linear regression method using enzyme kinetic modules. The enzyme operational stability study showed that Lipozyme IM20 retained 38.1% of the initial activity for the synthesis of palmitanilide (even after repeated use for 48 h). Palmitanilide, a fatty acid amide, exhibited potent antimicrobial activity toward Bacillus cereus. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Enzymatic Synthesis of Furfuryl Alcohol Ester with Oleic Acid by Candida antarctica Lipase B and Its Kinetic Study

    NASA Astrophysics Data System (ADS)

    Sengupta, Avery; Dey, Tanmoy; Ghosh, Mahua; Ghosh, Jaydip; Ghosh, Santinath

    2012-08-01

    This study investigated the successful enzymatic production of furfuryl oleate and its detailed kinetic study by Michaelis-Menten model. Esterification of oleic acid and furfuryl alcohol by Candida antarctica lipase B (Novozym 435 preparation) in a solvent free system was studied in the present work at 1:1 molar ratio of furfuryl alcohol and oleic acid. About 99 % conversion (on the basis of oleic acid) has been achieved within 6 h at 5 % enzyme concentration. Ping-pong bi-bi mechanism (inhibition phenomenon taken into account) was applied to describe the ratios as a complex kinetic model. The kinetic parameters were determined using MATLAB language programme. The two initial rate constants KA and KB respectively were found out by different progress curves plotted with the help of MATLAB language programme. It was concluded from the results that furfuryl alcohol considerably inhibited the enzymatic reaction while oleic acid had negligible inhibitory effect. It was clearly seen that the initial rate was increased with the increase in the furfuryl alcohol concentration until 2 M/L after which there was a drop in the initial rate depicting the inhibitory effect of furfuryl alcohol. Surprisingly, it has been observed that addition of 0.1 mol of product activated the esterification reaction. Finally, the model was found to be statistically fitting well with the experimental data.

  14. One-step synthesis of in situ reduced metal Bi decorated bismuth molybdate hollow microspheres with enhancing photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Jin, Meng; Lu, Shiyu; Ma, Li; Gan, Mengyu

    2017-02-01

    In this feature work, in situ metal Bi are successfully modified bismuth molybdate hollow spheres using an effective one-pot solvthermal reduction without any temple. In order to deeply understand the influence of reduction conditions on the texture, surface state, and photocatalytic performance of the resulting samples, a series of products were synthesized by tuning the temperatures. The similar morphology, surface area of photocatalysis (BMO-160 and BMO-170) were synthesized, only with the different composition. The detailed characterization and analysis distinctly suggested that increasing solvothermal reduction temperature led to Bi3+ was in situ reduced to elementary substance Bi0 by ethylene glycol gradually and dispersed very uniform in bismuth molybdate. Benefiting from the enhanced charge separation, transfer, and donor density resulting from the formation of Bi decorated bismuth molybdate where Bi as cocatalyst, the photocatalytic performance of the reductive Bi/Bi2-xMoOy hollow spheres (BMO-170) is higher than that of the untreated Bi2-xMoOy hollow spheres (BMO-160) for Rh6G degradation under visible light irradiation. Additionally, the reductive BMO-170 has a superior stability after five cycles.

  15. Immobilization of horseradish peroxidase onto kaolin.

    PubMed

    Šekuljica, Nataša Ž; Prlainović, Nevena Ž; Jovanović, Jelena R; Stefanović, Andrea B; Djokić, Veljko R; Mijin, Dušan Ž; Knežević-Jugović, Zorica D

    2016-03-01

    Kaolin showed as a very perspective carrier for the enzyme immobilization and it was used for the adsorption of horseradish peroxidase (HRP). The effects of the enzyme concentration and pH on the immobilization efficiency were studied in the reaction with pyrogallol and anthraquinone dye C.I. Acid Violet 109 (AV 109). In addition, Fourier transform infrared spectroscopy, scanning electron microscopy and analysis by Brunauer-Emmett-Teller were performed for kaolin, thermally activated kaolin and the immobilized enzyme. It has been shown that 0.1 IU of HRP-kaolin decolorized 87 % of dye solution, under the optimal conditions (pH 5.0, temperature 24 °C, dye concentration 40 mg/L and 0.2 mM of H2O2) within 40 min. The immobilized HRP decolorization follows the Ping Pong Bi-Bi mechanism with dead-end inhibition by the dye. The biocatalyst retained 35 ± 0.9 % of the initial activity after seven cycles of reuse in the decolorization reaction of AV 109 under optimal conditions in a batch reactor. The obtained kinetic parameters and reusability study confirmed improvement in performances of k-HRP compared to free, indicating that k-HRP has a great potential for environmental purposes.

  16. MatProps: Material Properties Database and Associated Access Library

    SciTech Connect

    Durrenberger, J K; Becker, R C; Goto, D M; Neely, J R; Wallin, B K

    2007-08-13

    Coefficients for analytic constitutive and equation of state models (EOS), which are used by many hydro codes at LLNL, are currently stored in a legacy material database (Steinberg, UCRL-MA-106349). Parameters for numerous materials are available through this database, and include Steinberg-Guinan and Steinberg-Lund constitutive models for metals, JWL equations of state for high explosives, and Mie-Gruniesen equations of state for metals. These constitutive models are used in most of the simulations done by ASC codes today at Livermore. Analytic EOSs are also still used, but have been superseded in many cases by tabular representations in LEOS (http://leos.llnl.gov). Numerous advanced constitutive models have been developed and implemented into ASC codes over the past 20 years. These newer models have more physics and better representations of material strength properties than their predecessors, and therefore more model coefficients. However, a material database of these coefficients is not readily available. Therefore incorporating these coefficients with those of the legacy models into a portable database that could be shared amongst codes would be most welcome. The goal of this paper is to describe the MatProp effort at LLNL to create such a database and associated access library that could be used by codes throughout the DOE complex and beyond. We have written an initial version of the MatProp database and access library and our DOE/ASC code ALE3D (Nichols et. al., UCRL-MA-152204) is able to import information from the database. The database, a link to which exists on the Sourceforge server at LLNL, contains coefficients for many materials and models (see Appendix), and includes material parameters in the following categories--flow stress, shear modulus, strength, damage, and equation of state. Future versions of the Matprop database and access library will include the ability to read and write material descriptions that can be exchanged between codes. It will

  17. Predicting SKS-splitting from 35 Myr of subduction and mantle flow evolution in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Chertova, Maria; Spakman, Wim; Faccenda, Manuele

    2017-04-01

    We investigate the development of mantle anisotropy associated with the evolution of the Rif-Gibraltar-Betic (RGB) slab of the western Mediterranean and predict SKS-splitting directions for comparison with the recent observations compiled in Diaz and Gallart (2014). Our numerical model of slab evolution starts at 35 Ma and builds on our on recent work (Chertova et al., 2014) with the extension of imposing mantle flow velocities on the side boundaries of the model (Chertova et al., 2017). For the calculation of the evolution of finite strain deformation from the mantle flow field and for prediction of SKS-splitting directions we use the modified D-Rex program of Faccenda (2014). We test the predicted splitting observations against present-day shear wave splitting observations for subduction models with open boundary conditions (Chertova, 2014) and for models with various prescribed mantle flow conditions on the model side boundaries. The latter are predicted time-dependent (1 Myr time steps) velocity boundary conditions computed from back-advection of a temperature and density model of the present-day mantle scaled from a global seismic tomography model (Steinberger et al., 2015). These boundary conditions where used recently to demonstrate the relative insensitivity of RGB slab position and overall slab morphology for external mantle flow (Chertova et al., 2017). Using open boundaries only we obtain a poor to moderate fit between predicted and observed splitting directions after 35 Myr of slab and mantle flow evolution. In contrast, a good fit is obtained when imposing the computed mantle flow velocities on the western, southern, and northern boundaries during 35 Myr of model evolution. This successful model combines local slab-driven mantle flow with remotely forced mantle flow. We are in the process to repeat these calculations for shorter periods of mantle flow evolution to determine how much of past mantle flow is implicitly recorded in present-day observation

  18. Eruption Sites of LIPs of the Past 250 My With Respect to the slow/fast D" Boundary in Four Improved Reference Frames

    NASA Astrophysics Data System (ADS)

    Torsvik, T. H.; Smethurst, M. A.; Burke, K.; Steinberger, B.

    2005-05-01

    We have shown (Burke and Torsvik 2004) that nearly all of the Large Igneous Provinces (LIPs) erupted on the Earth's surface during the past 250 My rose, at the time of their eruption, from the base of the mantle close to the 1 percent slow S-wave delta V contour of the D" zone. Here we report on the use of (1) Improved plate-circuitry (among PAC-ANT-AUS-MADAGAS-IND-SOAM-AFR) and (2) upgraded paleomagnetic data-sets to confirm and refine our results. In an attempt to establish whether rotation of LIPs to their sites at eruption can be used to learn something about mantle and core behavior over the past 250 My we have performed rotations on assumptions of: (1) a persistent geocentric axial magnetic dipole field, (2) a time-dependent non-dipole (octopole) magnetic field contribution (Torsvik and Van der Voo (2002), (3) a mantle wind contribution to mantle flow (Steinberger et al. 2004) and (4) a revised (new timescale) fixed hot-spot (no mantle wind) reference frame. Our test consisted of estimating how closely radials dropped from rotated LIP sets based on these four assumptions plotted to the 1 percent slow contour derived from seismic tomography. We compared S-wave tomographic models at the CMB and opted to use the SMEAN model (Becker and Boschi 2002) recognizing that other models are similar and that all have similar limitations. The mean deviation of the projected rotated LIPs from the 1 percent slow contour is 6 degrees at the CMB. The four different assumptions yield results between 6.5 and 5.5 degrees which seems unlikely to be a significant difference. Our conclusion is that it is not yet possible to discriminate among the four models of mantle and core behavior using our procedure. Becker, T.W and Boschi, L. 2002: A comparison of tomographic and geodynamic mantle models. Geochemistry, Geophysics, Geosystems 3, 2001GC000168. Burke, K. and Torsvik, T.H. 2004: Derivation of large igneous provinces of the past 200 million years from long-term heterogeneities in

  19. Inner gorge-slot canyon system produced by repeated stream incision (eastern Alps): Significance for development of bedrock canyons

    NASA Astrophysics Data System (ADS)

    Sanders, Diethard; Wischounig, Lukas; Gruber, Alfred; Ostermann, Marc

    2014-06-01

    Many inner bedrock gorges of the Alps show abrupt downstream changes in gorge width, as well as channel type and gradient, as a result of epigenetic incision of slot canyons. Many slot canyons also are associated with older gorge reaches filled with Quaternary deposits. The age of slot canyons and inner bedrock gorges, however, commonly is difficult to constrain. For the inner-bedrock gorge system of the Steinberger Ache catchment (eastern Alps), active slot canyons as well as older, abandoned gorge reaches filled with upper Würmian proglacial deposits record three phases of gorge development and slot-canyon incision. A 234U/230Th age of cement of 29.7 ± 1.8 ka in fluvial conglomerates onlapping the flank of an inner gorge fits with late Würmian valley-bottom aggradation shortly before pleniglacial conditions; in addition, the age indicates that at least the corresponding canyon reach must be older. During advance of ice streams in the buildup of the Last Glacial Maximum (LGM), the catchment was blocked, and a proglacial lake formed. Bedrock gorges submerged in that lake were filled with fluviolacustrine deposits. During the LGM, the entire catchment was overridden by ice. During post-glacial reincision, streams largely found again their preexisting inner bedrock canyons. In some areas, however, the former stream course was 'missed', and a slot canyon formed. The distribution of Pleistocene deposits, the patterns of canyon incision, and the mentioned U/Th cementation age, however, together record a further discrete phase of base-level rise and stream incision well before the LGM. The present course of Steinberger Ache and its tributaries is a patchwork of (1) slot canyons incised during post-glacial incision; (2) vestiges of slot canyons cut upon an earlier (middle to late Würmian?) cycle of base-level rise and fall; (3) reactivated reaches up to ~ 200 m in width of inner bedrock gorge that are watershed at present, and more than at least ~ 30 ka in age; and (4

  20. Mantle flow influence on the evolution of subduction systems.

    NASA Astrophysics Data System (ADS)

    Chertova, Maria; Spakman, Wim; Steinberger, Bernhard

    2016-04-01

    Evolution of the subducting slab has been widely investigated in the past two decades be means of numerical and laboratory modeling, including analysis of the factors controlling its behavior. However, until present, relatively little attention has been paid to the influence of the mantle flow. While for large subduction zones, due to the high slab buoyancy force, this effect might be small, mantle flow might be a primary factor controlling the evolution of a regional subduction zone. Here we investigate the impact of prescribed mantle flow on the evolution of both generic and real-Earth subduction models by means of 3D thermo-mechanical numerical modeling. The generic setup consists of a laterally symmetric subduction model using a 3000×2000×1000 km modeling domain with a lateral slab width varying from 500 to 1500 km. Non-linear rheology is implemented including diffusion, dislocation creep and a viscosity-limiter. To satisfy mass conservation, while implementing mantle inflow on some side boundaries, we keep other sides open (Chertova et al. 2012). To test the mantle flow influence on the dynamics of real-Earth subduction zone we adopt the numerical model from Chertova et al. (2014) for the evolution of the western Mediterranean subduction since 35 Ma. First, this model was tested with the arbitrary mantle flow prescribed on one of the four side boundaries or for the combination of two boundaries. In the last set of experiments, for side boundary conditions we use time-dependent estimates of actual mantle flow in the region based on Steinberger (2015) given for every 1 My. We demonstrate that for the western-Mediterranean subduction, the surrounding mantle flow is of second-order compared to slab buoyancy in controlling the dynamics of the subducting slab. Introducing mantle flow on the side boundaries might, however, improve the fit between the modeled and real slab imaged by tomography, although this may also trade-off with varying rheological parameters of

  1. A temperature-sensitive trpS mutation interferes with trp RNA-binding attenuation protein (TRAP) regulation of trp gene expression in Bacillus subtilis.

    PubMed

    Lee, A I; Sarsero, J P; Yanofsky, C

    1996-11-01

    In Bacillus subtilis, the tryptophan-activated trp RNA-binding attenuation protein (TRAP) regulates expression of the seven tryptophan biosynthetic genes by binding to specific repeat sequences in the transcripts of the trp operon and of the folate operon, the operon containing trpG. Steinberg observed that strains containing a temperature-sensitive mutant form of tryptophanyl-tRNA synthetase, encoded by the trpS1 allele, produced elevated levels of the tryptophan pathway enzymes, when grown at high temperatures in the presence of excess L-tryptophan (W. Steinberg, J. Bacteriol. 117:1023-1034, 1974). We have confirmed this observation and have shown that expression of two reporter gene fusions, trpE'-'lacZ and trpG'-'lacZ, is also increased under these conditions. Deletion of the terminator or antiterminator RNA secondary structure involved in TRAP regulation of trp operon expression eliminated the trpS1 effect, suggesting that temperature-sensitive expression was mediated by the TRAP protein. Analysis of expression of mtrB, the gene encoding the TRAP subunit, both by examination of a lacZ translational fusion and by measuring the intracellular levels of TRAP by immunoblotting, indicated that the trpS1-induced increase in trp gene expression was not due to inhibition of mtrB expression or to alteration of the amount of TRAP present per cell. Increasing the cellular level of TRAP by overexpressing mtrB partially counteracted the trpS1 effect, demonstrating that active TRAP was limiting in the trpS1 mutant. We also showed that elevated trp operon expression was not due to increased transcription initiation at the upstream aroF promoter, a promoter that also contributes to trp operon expression. We postulate that the increase in trp gene expression observed in the trpS1 mutant is due to the reduced availability of functional TRAP. This could result from inhibition of TRAP function by uncharged tRNA(Trp) molecules or by increased synthesis of some other transcript

  2. Plume Generation Zones On The Core Mantle Boundary: their origin and what they tell about how the Earth works - and how it has worked (Arthur Holmes Medal Lecture)

    NASA Astrophysics Data System (ADS)

    Burke, Kevin

    2014-05-01

    proving useful in the interpretation of mantle behaviour (For example: TPW, Steinberger and Torsvik 2008) and represent an as yet not fully utilized opportunity for improving understanding of the solid Earth. SUCCINCT REFERENCES: Burke et al. EPSLv.265, 2008, Burke et al. GRL v.39.2012, Garnero et al. GSA Mem.430, 2007, Morgan 1972 GSA Mem.132, Steinberger and Torsvik, Nature v.452, 2008, Torsvik et al Nature v.466, 2010, Wilson Can. J. Physics 1963.

  3. Revisiting ISEE-3-Voyager Observations of Back-Side Type III Radio Bursts in View of the Stereo/Waves observations.

    NASA Astrophysics Data System (ADS)

    Bougeret, J.; Lecacheux, A.; Hoang, S.; Maksimovic, M.

    2004-12-01

    In this paper, we revisit old observations of interplanetary type III radio bursts made simultaneously by the radio instruments on the ISEE-3 spacecraft and on the Voyager spacecraft, in view of the new opportunities offered by the Stereo mission.. Type III radio emission is produced by beams of supra-thermal electrons believed to be accelerated during the flare process and traveling along open interplanetary field lines. Their observation can help trace the large scale structure of the interplanetary medium. Lecacheux et al. (1989) analyzed the properties of such radio bursts originating behind the Sun as viewed from the Earth and still also observed by the ISEE-3 spacecraft located at the L1 libration point. Information on the beaming of the radiation can be deduced from these observations. Lecacheux et al. also measured anomalous delays in burst arrival time at one spacecraft relative to the other. These anomalous delays could be explained by the presence of both the fundamental and harmonic radiation modes with different beaming properties. Such an hypothesis can be checked by the Stereo/Waves observations. Finally, we discuss previous radio wave propagation models in the interplanetary medium and emphasize their importance for the interpretation of the radio observations. Lecacheux, A., J.-L. Steinberg, S. Hoang, and G. A. Dulk, Characteristics of type III bursts in the solar wind from simultaneous observations on board ISEE-3 and Voyager, Astron. Astrophys. 217, 237-250, 1989.

  4. Los Alamos Radiation Hydrocode Models of Asteroid Mitigation by a Subsurface Explosion

    NASA Astrophysics Data System (ADS)

    Weaver, R.; Plesko, C. S.; Dearholt, W.

    2010-12-01

    Mitigation of a potentially hazardous object (PHO) by a nuclear subsurface explosion is considered. In this new work we examine non-central subsurface emplacements and seek an optimal depth-of-burial for various explosion energies. This intervention methodology has been popularized in media presentations and is considered as one possible method of impact-hazard mitigation. We present new RAGE radiation hydrocode models of the shock-generated disruption of PHOs by subsurface nuclear bursts and deflection from shallow buried bursts using scenario-specific models from authentic RADAR shape models. We will show 2D and 3D models for the disruption by a large energy source at the center and near the edge (mitigation) of such PHO models (1-10 Mton TNT equivalent), specifically for asteroid 25143 Itokawa. Parametric studies will be done on: the value of the source energy (from 100 Kton to 10 Mton), the parameters in the Steinberg-Guinan strength model used and the internal composition of the object from uniform composition to a “rubble pile” distribution. Specifically we are interested in assessing the optimum depth of burial and energy required to essentially disrupt and/or move the PHO and therefore mitigate the hazard. Recollection will be considered. (LA-UR-10-05860) A subsurface 1 Mt explosion near the long-axis surface of an Itokawa shape model with a non-uniform internal composition. The resulting velocity imparted to the bulk remainder of the object is ~50 m/s.

  5. Los Alamos Radiation Hydrocode Models of Asteroid Mitigation by an Internal Explosion

    NASA Astrophysics Data System (ADS)

    Weaver, Robert; Plesko, C.; Dearholdt, W.

    2010-10-01

    Mitigation of a potentially hazardous object (PHO) by a conventional or nuclear subsurface burst is considered. This intervention methodology has been popularized in media presentations and is considered as one possible method of impact-hazard mitigation. We present RAGE radiation hydrocode models of the shock-generated disruption of PHOs by subsurface nuclear bursts and deflection from shallow buried bursts using scenario-specific models from authentic RADAR shape models. We will show 2D and 3D models for the disruption by a large energy source at the center and near the edge (mitigation) of such PHO models (1-10 Mton TNT equivalent), specifically for asteroid 25143 Itokawa. Parametric studies will be done on: the value of the source energy (from 1 Mton to 10 Mton), the parameters in the Steinberg-Guinan strength model used and the internal composition of the object from uniform composition to a "rubble pile” distribution. Specifically we are interested in assessing the optimum depth of burial and energy required to essentially disrupt and/or move the PHO and therefore mitigate the hazard. Recollection will be considered.

  6. Trajectory-based interpretation of Young's experiment, the Arago-Fresnel laws and the Poisson-Arago spot for photons and massive particles

    NASA Astrophysics Data System (ADS)

    Davidović, Milena; Sanz, Ángel S.; Božić, Mirjana; Arsenović, Dušan; Dimić, Dragan

    2013-03-01

    We present a trajectory-based interpretation of Young's experiment, the Arago-Fresnel laws and the Poisson-Arago spot. This approach is based on the equation of the trajectory associated with the quantum probability current density in the case of massive particles, and the Poynting vector for the electromagnetic field in the case of photons. Both the form and properties of the evaluated photon trajectories are in good agreement with the averaged trajectories of single photons observed recently in Young's experiment by Steinberg's group at the University of Toronto. In the case of the Arago-Fresnel laws for polarized light, the trajectory interpretation presented here differs from interpretations based on the concept of ‘which-way’ (or ‘which-slit’) information and quantum erasure. More specifically, the observer's information about the slit that the photons went through is not relevant to the existence of interference; what is relevant is the form of the electromagnetic energy density and its evolution, which will model consequently the distribution of trajectories and their topology. Finally, we also show that the distributions of end points of a large number of evaluated photon trajectories are in agreement with the distributions measured at the screen behind a circular disc, clearly giving rise to the Poisson-Arago spot.

  7. Quark Matter 2011 (QM11) Quark Matter 2011 (QM11)

    NASA Astrophysics Data System (ADS)

    2011-12-01

    International Advisory Committee Antinori, FedericoPaic, Guy Braun-Munzinger, PeterPajares, Carlos Cifarelli, LuisaPeitzmann, Thomas Erazmus, BarbaraRedlich, Krzysztof Eskola, KariRiccati, Lodovico Gaardhøje, Jens JørgenRoland, Gunther Gale, CharlesRoy, Christelle Gelis, FrancoisSchukraft, Jürgen Giubellino, PaoloSinha, Bikash Greiner, CarstenSrivastava, Dinesh Gyulassy, MiklosStachel, Johanna Harris, JohnSteinberg, Peter Hatsuda, TetsuoStroth, Joachim Heinz, UlrichSugitate, Toru Jacak, BarbaraTserruya, Itzhak Karsch, FrithjofVelkovska, Julia Kharzeev, DimaWang, Enke Kodama, TakeshiWang, Xin, Nian Lévai, PéterWessels, Johannes Manko, VladislavXu, Nu Müller, BerndtZajc, William Ollitrault, Jean-Yves Organizing Committee Arleo, FrancoisDupieux, Pascal Bastid, NicoleFurget, Christophe Bourgeois, Marie-LaureGranier de Cassagnac, Raphael Bregant, MarcoGuernane, Rachid Carminati, FedericoHervet, Carnita Castillo, JavierKuhn, Christian Cheynis, BrigitteOlivier, Nathalie Conesa, DelValle, Zaida Connor, MichelleRenshall, Lucy Crochet, PhilippeSuire, Christophe Delagrange, HuguesTihinen, Ulla Program Committee Schutz, Yves (Chair)Baldisseri, Alberto Wiedemann, Urs (co-Chair)Safarik, Karel Aurenche, Patrick

  8. ALE3D Model Predictions and Experimental Analysis of the Cookoff Response of Comp B*

    SciTech Connect

    Maienschein, J L; McClelland, M A; Wardell, J F; Reaugh, J E; Nichols, A L; Tran, T D

    2003-11-24

    ALE3D simulations are presented for the thermal explosion of Comp B (RDX,TNT) in a Scaled Thermal Explosion Experiment (STEX). Candidate models and numerical strategies are being tested using the ALE3D code which simulates the coupled thermal, mechanical, and chemical behavior during heating, ignition, and explosion. The mechanical behavior of the solid constituents is represented by a Steinberg-Guinan model while polynomial and gamma-law expressions are used for the equation of state of the solid and gas species, respectively. A gamma-law model is employed for the air in gaps, and a mixed material model is used for the interface between air and explosive. A three-step chemical kinetics model is used for each of the RDX and TNT reaction sequences during the heating and ignition phases, and a pressure-dependent deflagration model is employed during the rapid expansion. Parameters for the three-step kinetics model are specified using measurements of the One-Dimensional-Time-to-Explosion (ODTX), while measurements for burn rate are employed to determine parameters in the burn front model. We compare model predictions to measurements for temperature fields, ignition temperature, and tube wall strain during the heating, ignition, and explosive phases.

  9. Numerical Simulations of Fragmentation Onset Velocity of Projectile Impact on Thin Bumper

    NASA Astrophysics Data System (ADS)

    Wei, Zhang; Caixia, Jiang; Wenlai, Ma; Baojun, Pang

    2007-12-01

    The conventional spacecraft meteoroids and orbital debris shielding system is the Whipple shield. In general there is a threshold velocity that is just sufficient to shatter the projectile for each system consisting of a projectile and bumper. This velocity is known as the fragmentation onset velocity. To determine the fragmentation onset velocity experimentally, a number of experiments have been conducted with different projectile/bumper configuration. The numerical simulations of fragmentation onset velocity of different material projectile hypervelocity impacts on bumpers with different combination of impact velocities and bumper-thicker-to-projectile-diameter ratios (t/D) have been performed using the SPH technique of AUTODYN. The spherical projectile materials are aluminum, steel and copper. All bumper material is aluminum alloy 6061-T6. The simulation velocities were in the range of 1 km/s˜7 km/s. The ratios of t/D were varied from 0.01 to 0.8. The material model contains Mie-Gruneisen (shock) equation of state, Steinberg-Guinan strength model, principal tensile stress failure model and Grady fragmentation failure model. The simulation results are given and compared with the experimental results. The simulation results are consistent very well with the experimental results. The effects of t/D and material shock impedance etc. on fragmentation onset velocity have been given in Figures and equations.

  10. Numerical Simulations of Fragmentation Onset Velocity of Projectile Impact on Thin Bumper

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Jiang, Caixia; Ma, Wenlai; Pang, Baojun

    2007-06-01

    The conventional spacecraft meteoroids and orbital debris shielding system is the Whipple shield. In general there is a threshold velocity that is just sufficient to shatter the projectile for each system consisting of a projectile and bumper. This velocity is known as the fragmentation onset velocity. To determine the fragmentation onset velocity experimentally, a number of experiments have been conducted with different projectile/bumper configuration. The numerical simulation of fragmentation onset velocity of different material projectile hypervelocity impacts on bumpers with different combination of impact velocities and bumper-thicker-to-projectile-diameter ratios (t/D) has been performed using the SPH technique of AUTODYN. The spherical projectile materials are aluminum, steel and copper. All bumper materials are aluminum alloy 6061-T6. The simulation velocities were in the range of 1km/s-7km/s. The ratios of t/D were varied from 0.01 to 0.80. The material models were consisted of Mie-Gruneisen (shock) equation of state, Steinberg-Guinan strength model and Grady fragmentation failure model. The simulation results are given and compared with the experimental results. The simulation results are consistent very well with the experimental results.

  11. Critical Plastic Strain as a Criterion for Failure in Ballistic Impact Experiments of U/Ti and Ti64 Alloys

    SciTech Connect

    Herrmann, B.; Shvarts, D.; Favorsky, V.; Zaretsky, E.

    2006-07-28

    Strain localization and failure in U-0.75Ti and Ti-6Al-4V alloys were studied in symmetric (rod-on-rod) and reverse ballistic (disk-on-rod) impact experiments, accompanied by VISAR monitoring of the lateral sample surface velocity. Softly-recovered samples were metallurgically examined, and the experiments were numerically simulated using an AUTODYN trade mark sign 2-D code. Satisfactory reproduction of both the measured velocity profiles and the results of metallographic examination of the damage produced by adiabatic shearing were obtained by using the Steinberg-Cochran-Guinan-type constitutive equation (calibrated in preliminary planar impact experiments) and the AUTODYN trade mark sign built-in erosion function. A good agreement was found between strains, measured by using natural markers (martensite in U/Ti and texture in Ti64), corresponding to the onset of adiabatic shearing (0.5 - 1.0) and the value of the critical plastic strain used in the simulations as a criterion for triggering the erosion function (0.6 for both alloys). In the case of Ti64 the shearing is finalized by cracking at observed strain values of 1.0 - 1.5, whereas in the U/Ti the shear strain reaches values greater by at least one order of magnitude and is terminated by void growth and coalescence.

  12. Cookoff Response of PBXN-109: Material Characterization and ALE3D Thermal Predictions

    SciTech Connect

    McClelland, M A; Tran, T D; Cunningham, B J; Weese, R K; Maienschein, J L

    2001-08-21

    Materials properties measurements are made for the RDX-based explosive, PBXN-109, and initial ALE3D model predictions are given for the cookoff temperature in a U.S. Navy test. This work is part of an effort in the U.S. Navy and Department of Energy (DOE) laboratories to understand the thermal explosion behavior of this material. Benchmark cookoff experiments are being performed by the U.S. Navy to validate DOE materials models and computer codes. The ALE3D computer code can model the coupled thermal, mechanical, and chemical behavior of heating, ignition, and explosion in cookoff tests. In our application, a standard three-step step model is selected for the chemical kinetics. The strength behavior of the solid constituents is represented by a Steinberg-Guinan model while polynomial and gamma-law expressions are used for the Equation Of State (EOS) for the solid and gas species, respectively. Materials characterization measurements are given for thermal expansion, heat capacity, shear modulus, bulk modulus, and One-Dimensional-Time-to-Explosion (ODTX). These measurements and those of the other project participants are used to determine parameters in the ALE3D chemical, mechanical, and thermal models. Time-dependent, two-dimensional results are given for the temperature and material expansion. The results show predicted cookoff temperatures slightly higher than the measured values.

  13. ALE3D Model Predictions and Materials Characterization for the Cookoff Response of PBXN-109

    SciTech Connect

    McClelland, M A; Maienschein, J L; Nichols, A L; Wardell, J F; Atwood, A I; Curran, P O

    2002-03-19

    ALE3D simulations are presented for the thermal explosion of PBXN-109 (RDX, AI, HTPB, DOA) in support of an effort by the U. S. Navy and Department of Energy (DOE) to validate computational models. The U.S. Navy is performing benchmark tests for the slow cookoff of PBXN-109 in a sealed tube. Candidate models are being tested using the ALE3D code, which can simulate the coupled thermal, mechanical, and chemical behavior during heating, ignition, and explosion. The strength behavior of the solid constituents is represented by a Steinberg-Guinan model while polynomial and gamma-law expressions are used for the Equation Of State (EOS) for the solid and gas species, respectively. A void model is employed to represent the air in gaps. ALE3D model 'parameters are specified using measurements of thermal and mechanical properties including thermal expansion, heat capacity, shear modulus, and bulk modulus. A standard three-step chemical kinetics model is used during the thermal ramp, and a pressure-dependent burn front model is employed during the rapid expansion. Parameters for the three-step kinetics model are specified using measurements of the One-Dimensional-Time-to-Explosion (ODTX), while measurements for burn rate of pristine and thermally damaged material are employed to determine parameters in the burn front model. Results are given for calculations in which heating, ignition, and explosion are modeled in a single simulation. We compare model results to measurements for the cookoff temperature and tube wall strain.

  14. Cookoff Response of PBXN-109: Material Characterization and ALE3D Thermal Predictions

    SciTech Connect

    McClelland, M A; Tran, T D; Cunningham, B J; Weese, R K; Maienschein, J L

    2001-05-29

    Materials properties measurements are made for the RDX-based explosive, PBXN-109, and initial ALE3D model predictions are given for the cookoff temperature in a U.S. Navy test. This work is part of an effort in the U.S. Navy and Department of Energy (DOE) laboratories to understand the thermal explosion behavior of this material. Benchmark cookoff experiments are being performed by the U.S. Navy to validate DOE materials models and computer codes. The ALE3D computer code can model the coupled thermal, mechanical, and chemical behavior of heating, ignition, and explosion in cookoff tests. In our application, a standard three-step step model is selected for the chemical kinetics. The strength behavior of the solid constituents is represented by a Steinberg-Guinan model while polynomial and gamma-law expressions are used for the Equation Of State (EOS) for the solid and gas species, respectively. Materials characterization measurements are given for thermal expansion, heat capacity, shear modulus, bulk modulus, and One-Dimensional-Time-to-Explosion (ODTX). These measurements and those of the other project participants are used to determine parameters in the ALE3D chemical, mechanical, and thermal models. Time-dependent, two-dimensional results are given for the temperature and material expansion. The results show predicted cookoff temperatures slightly higher than the measured values.

  15. Microstructure and Mechanical Properties of 21-6-9 Stainless Steel Electron Beam Welds

    NASA Astrophysics Data System (ADS)

    Elmer, John W.; Ellsworth, G. Fred; Florando, Jeffrey N.; Golosker, Ilya V.; Mulay, Rupalee P.

    2017-04-01

    Welds can either be stronger or weaker than the base metals that they join depending on the microstructures that form in the fusion and heat-affected zones of the weld. In this paper, weld strengthening in the fusion zone of annealed 21-6-9 stainless steel is investigated using cross-weld tensile samples, hardness testing, and microstructural characterization. Due to the stronger nature of the weld, the cross-weld tensile tests failed in the base metal and were not able to generate true fusion zone mechanical properties. Nanoindentation with a spherical indenter was instead used to predict the tensile behavior for the weld metal. Extrapolation of the nanoindentation results to higher strains was performed using the Steinberg-Guinan and Johnson-Cook strength models, and the results can be used for weld strength modeling purposes. The results illustrate how microstructural refinement and residual ferrite formation in the weld fusion zone can be an effective strengthener for 21-6-9 stainless steel.

  16. The development of reproductive strategy in females: early maternal harshness --> earlier menarche --> increased sexual risk taking.

    PubMed

    Belsky, Jay; Steinberg, Laurence; Houts, Renate M; Halpern-Felsher, Bonnie L

    2010-01-01

    To test a proposition central to J. Belsky, L. Steinberg, and P. Draper's (1991) evolutionary theory of socialization-that pubertal maturation plays a role in linking early rearing experience with adolescent sexual risk taking (i.e., frequency of sexual behavior) and, perhaps, other risk taking (e.g., alcohol, drugs, delinquency)-the authors subjected longitudinal data on 433 White, 62 Black, and 31 Hispanic females to path analysis. Results showed (a) that greater maternal harshness at 54 months predicted earlier age of menarche; (b) that earlier age of menarche predicted greater sexual (but not other) risk taking; and (c) that maternal harshness exerted a significant indirect effect, via earlier menarche, on sexual risk taking (i.e., greater harshness --> earlier menarche --> greater sexual risk taking) but only a direct effect on other risk taking. Results are discussed in terms of evolutionary perspectives on human development and reproductive strategy, and future directions for research are outlined. Copyright 2009 APA, all rights reserved.

  17. Cell adhesion and sorting in embryoid bodies derived from N- or E-cadherin deficient murine embryonic stem cells

    PubMed Central

    Moore, Robert; Tao, Wensi; Meng, Yue; Smith, Elizabeth R.; Xu, Xiang-Xi

    2014-01-01

    Summary The primitive endoderm epithelial structure in mouse blastocysts forms following cell differentiation and subsequent sorting, and this two-step process can be reproduced in vitro using an embryoid body model. We found that in the chimeric embryoid bodies consisting of paired wildtype and E-cadherin null ES cells, the wildtype sorted to the center and were enveloped by the less adhesive E-cadherin null cells, in accord with Steinberg's hypothesis. However, wildtype and N-cadherin null ES cells intermixed and did not segregate, a situation that may be explained by Albert Harris' modified principle, which incorporates the unique properties of living cells. Furthermore, in chimeric embryoid bodies composed of N-cadherin and E-cadherin null ES cells, the two weakly interacting cell types segregated but did not envelop one another. Lastly, the most consistent and striking observation was that differentiated cells sorted to the surface and formed an enveloping layer, regardless of the relative cell adhesive affinity of any cell combination, supporting the hypothesis that the ability of the differentiated cells to establish apical polarity is the determining factor in surface sorting and positioning. PMID:24414205

  18. High-Pressure Strength Determination via Quasi-Elastic Optimization Analysis

    NASA Astrophysics Data System (ADS)

    Brown, Justin; Vogler, Tracy; Asay, Jim

    2012-02-01

    The analysis of unloading profiles from ramp wave experiments on Sandia's Z machine for the purposes of extracting strength information can be greatly influenced by the presence of a window. An impedance mismatch between the sample and the window generates a reflected ramp wave which perturbs the incoming wave, particularly at later times when, during unloading, the material strength becomes evident. In an effort to analyze the waveforms for an accurate estimate of the strength, the experimental data is coupled with optimized numerical simulations. Simulations were performed with LASLO, a one-dimensional magneto-hydrodynamics code. The deviatoric response was calculated using a modified rate-independent Steinberg - Guinan model in which a quasi-elastic response was implemented during unloading by linearly varying the shear modulus. A best fit of relevant parameters in this strength model along with the magnetic field at the drive surface were estimated over the course of thousands of simulations using the Dakota optimization package. These results may then be used to estimate the in situ wave profiles from which the strength can be extracted. Initial results will be presented for ramp wave compression of tantalum with a lithium fluoride window to peak stresses of ˜120 GPa. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin company, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  19. Further Empirical Results on Parametric Versus Non-Parametric IRT Modeling of Likert-Type Personality Data.

    PubMed

    Maydeu-Olivares, Albert

    2005-04-01

    Chernyshenko, Stark, Chan, Drasgow, and Williams (2001) investigated the fit of Samejima's logistic graded model and Levine's non-parametric MFS model to the scales of two personality questionnaires and found that the graded model did not fit well. We attribute the poor fit of the graded model to small amounts of multidimensionality present in their data. To verify this conjecture, we compare the fit of these models to the Social Problem Solving Inventory-Revised, whose scales were designed to be unidimensional. A calibration and a cross-validation sample of new observations were used. We also included the following parametric models in the comparison: Bock's nominal model, Masters' partial credit model, and Thissen and Steinberg's extension of the latter. All models were estimated using full information maximum likelihood. We also included in the comparison a normal ogive model version of Samejima's model estimated using limited information estimation. We found that for all scales Samejima's model outperformed all other parametric IRT models in both samples, regardless of the estimation method employed. The non-parametric model outperformed all parametric models in the calibration sample. However, the graded model outperformed MFS in the cross-validation sample in some of the scales. We advocate employing the graded model estimated using limited information methods in modeling Likert-type data, as these methods are more versatile than full information methods to capture the multidimensionality that is generally present in personality data.

  20. Speech and hearing acoustics at Bell Labs

    NASA Astrophysics Data System (ADS)

    Allen, Jont

    2004-05-01

    A. G. Bell's interest in basic research of speech and hearing was one of the keys to the Bell Lab culture. When the first network circuits were built, speech quality was very low. Research was needed on speech articulation (the probability correct for nonsense speech sounds). George Campbell, a mathematician and ultimate engineer, and expert on Heaviside, extended work of Lord Rayleigh. In 1910 Campbell was the first to generate consonant identification confusion matrices, and show sound grouping (features). Crandall took up this work and attempted (but failed) to define the articulation density over frequency. By 1921 Fletcher had solved Crandall's problem, with the the Articulation Index theory, based on the idea of independent feature perception, across frequency and time. In 1929 he wrote his first book, Speech and Hearing, which sold over 5000 copies. His second book, Speech and Hearing in Communications, was first released in 1953, after his retirement. Other key people that worked closely with Fletcher were J. C. Steinberg, Munson, French, Galt, Hartley, Kingsbury, Nyquist, Sivian, White, and Wegel. I will try to introduce each of these people and describe their contributions to the speech and hearing field.

  1. First Principles Thermoelasticity of Tantalum at High Pressures

    SciTech Connect

    Orlikowski, D.A.; Soderlind, P.; Moriarty, J.

    2002-06-21

    The thermoelastic properties of bcc tantalum have been investigated over a broad range of temperatures (up to 12000 K) and pressures (up to 10 Mbar) using first-principles methods that account for cold, electron-thermal, and ion-thermal contributions. Specifically, we have combined ab initio all electron electronic-structure calculations for the cold and electron-thermal contributions to the elastic moduli with phonon contributions for the ion-thermal part calculated using model generalized pseudopotential theory (MGPT). For the latter, a summation of terms over the Brillouin zone is performed within the quasi-harmonic approximation, where each term is composed of a strain derivative of the phonon frequency at a particular k-point. At ambient pressure, the resulting temperature dependence of the elastic moduli is in excellent agreement with ultrasonic measurements. The experimentally observed anomalous behavior of C44 at low temperatures is shown to originate from the electron-thermal contribution. At higher temperatures, the dominant contribution to the temperature dependence of the elastic moduli comes from thermal expansion. Also, the pressure dependence of the moduli compares well with recent diamond and cell measurements up to 105 GPa. The calculated longitudinal and bulk sound velocities at higher pressure and temperature agree well with data obtained from shock experiments. Additionally, the temperature dependence of the Steinberg-Guinan model is examined for ambient pressure.

  2. Fluctuations and differential contraction during regeneration of Hydra vulgaris tissue toroids

    NASA Astrophysics Data System (ADS)

    Krahe, Michael; Wenzel, Iris; Lin, Kao-Nung; Fischer, Julia; Goldmann, Joseph; Kästner, Markus; Fütterer, Claus

    2013-03-01

    We studied regenerating bilayered tissue toroids dissected from Hydra vulgaris polyps and relate our macroscopic observations to the dynamics of force-generating mesoscopic cytoskeletal structures. Tissue fragments undergo a specific toroid-spheroid folding process leading to complete regeneration towards a new organism. The time scale of folding is too fast for biochemical signalling or morphogenetic gradients, which forced us to assume purely mechanical self-organization. The initial pattern selection dynamics was studied by embedding toroids into hydro-gels, allowing us to observe the deformation modes over longer periods of time. We found increasing mechanical fluctuations which break the toroidal symmetry, and discuss the evolution of their power spectra for various gel stiffnesses. Our observations are related to single-cell studies which explain the mechanical feasibility of the folding process. In addition, we observed switching of cells from a tissue bound to a migrating state after folding failure as well as in tissue injury. We found a supra-cellular actin ring assembled along the toroid's inner edge. Its contraction can lead to the observed folding dynamics as we could confirm by finite element simulations. This actin ring in the inner cell layer is assembled by myosin-driven length fluctuations of supra-cellular F-actin bundles (myonemes) in the outer cell layer. This paper is dedicated to Malcolm Steinberg.

  3. 2169 Steel Waveform Experiments

    NASA Astrophysics Data System (ADS)

    Furnish, M.; Alexander, C.; Reinhart, W.; Brown, J.

    2013-06-01

    In support of efforts to develop multiscale models of materials, we performed eight gas gun impact experiments on 2169 steel (21% Cr, 6% Ni, 9% Mn). These experiments provided shock, reshock and release velocimetry data, with initial shock stresses ranging from 10 to 50 GPa (particle velocities from 0.25 to 1.05 km/s). Both windowed and free-surface measurements were used, with samples 1 to 5 mm thick. The study focused on dynamic strength determination via the release/reshock paths. Reshock tests with explosively welded impactors produced clean results. The free-surface samples, which were steps on a single piece of steel, showed lower wavespeeds for thin (1 mm) samples than for thicker (2 or 4 mm) samples. A configuration used for the last three shots allowed release information to be determined from these free surface samples as well. The sample strength appears to increase with stress from ~1 GPa to ~3 GPa over this range, consistent with other recent work but about 40% above the Steinberg model. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  4. Fabry-Perot measurements and analysis of TOW-2A liner collapse and jet formation

    SciTech Connect

    Simonson, S.C.; Winer, K.A.; Breithaupt, R.D.; Avara, G.R.; Baum, D.W.

    1996-07-01

    A TOW-2A 146 mm shaped charge was fired and observed with five beam Fabry-Perot laser velocimetry. The liner collapse velocities were measured at five lines of sight covering the outer half of the liner. A record of 8-10 {mu}s in length was obtained for each sight line The velocity records at late time differ for each location, reflecting the varying charge-to-mass ratio as the end of the liner is approached. The results were analyzed with the CALE-2D hydrodynamic simulation code. The calculations reproduce the jump-off times, the shapes of the velocity jumps and the late time velocity asymptotes, but they underestimate the jump-off velocities by 6-7%. The calculations show that there exist no features in the velocity records that require spallation to account for them. Rather, the standard Steinberg-Guinan material model adequately accounts for the response of this copper liner to LX-14.

  5. Three Dimensional Dirac Semimetals

    NASA Astrophysics Data System (ADS)

    Zaheer, Saad

    2014-03-01

    Dirac points on the Fermi surface of two dimensional graphene are responsible for its unique electronic behavior. One can ask whether any three dimensional materials support similar pseudorelativistic physics in their bulk electronic spectra. This possibility has been investigated theoretically and is now supported by two successful experimental demonstrations reported during the last year. In this talk, I will summarize the various ways in which Dirac semimetals can be realized in three dimensions with primary focus on a specific theory developed on the basis of representations of crystal spacegroups. A three dimensional Dirac (Weyl) semimetal can appear in the presence (absence) of inversion symmetry by tuning parameters to the phase boundary separating a bulk insulating and a topological insulating phase. More generally, we find that specific rules governing crystal symmetry representations of electrons with spin lead to robust Dirac points at high symmetry points in the Brillouin zone. Combining these rules with microscopic considerations identifies six candidate Dirac semimetals. Another method towards engineering Dirac semimetals involves combining crystal symmetry and band inversion. Several candidate materials have been proposed utilizing this mechanism and one of the candidates has been successfully demonstrated as a Dirac semimetal in two independent experiments. Work carried out in collaboration with: Julia A. Steinberg, Steve M. Young, J.C.Y. Teo, C.L. Kane, E.J. Mele and Andrew M. Rappe.

  6. Hyperbaric oxygen therapy as a treatment for stage-I avascular necrosis of the femoral head.

    PubMed

    Reis, N D; Schwartz, O; Militianu, D; Ramon, Y; Levin, D; Norman, D; Melamed, Y; Shupak, A; Goldsher, D; Zinman, C

    2003-04-01

    Avascular necrosis (AVN) of the head of the femur is a potentially crippling disease which mainly affects young adults. Although treatment by exposure to hyperbaric oxygen (HBO) is reported as being beneficial, there has been no study of its use in treated compared with untreated patients. We selected 12 patients who suffered from Steinberg stage-I AVN of the head of the femur (four bilateral) whose lesions were 4 mm or more thick and/or 12.5 mm or more long on MRI. Daily HBO therapy was given for 100 days to each patient. All smaller stage-I lesions and more advanced stages of AVN were excluded. These size criteria were chosen in order to compare outcomes with an identical size of lesion in an untreated group described earlier. Overall, 81% of patients who received HBO therapy showed a return to normal on MRI as compared with 17% in the untreated group. We therefore conclude that hyperbaric oxygen is effective in the treatment of stage-I AVN of the head of the femur.

  7. Hereditary pancreatitis associated with a balanced translocation (5q;11p)

    SciTech Connect

    Dasouki, J.J.; Summar, M.L.; Mixon, C.

    1994-09-01

    Dominantly inherited pancreatitis was first described by Comfort and Steinberg in 1952. It is estimated to account for <1% of all childhood pancreatitis cases. Patients as young as 17 months of age were reported. Presentation varies from acute abdominal pain mimicking familial Mediterranean fever to more chronic steatorrhea causing malabsorption. Urinary excretion of cystine in both affected and unaffected family members is an unexplained feature. Our 37 year old, G{sub 1}P{sub 0{minus}1} proband is known to have familial pancreatitis which complicated her current pregnancy. Family history was also positive in her mother and a sister who has a 12 year old daughter with recurrent abdominal pain. The proband sought genetic counselling because her amniocentesis showed a male fetus with an apparently balanced reciprocal translocation: t(5;11)(q13;p15). A detailed fetal ultrasound examination failed to show any abnormality. On chromosomal analysis, the proband was found to have a similar translocation. Her plasma aminogram was normal, however the spot and 24 hour urine aminograms demonstrated generalized aminoaciduria. This is the first report of hereditary pancreatitis with a segregating balanced autosomal translocation which may be etiologically important. In addition, unlike what was described previously, the aminoaciduria was generalized and nonspecific. Molecular analysis of the genes located in the breakpoint region may prove to be helpful in identifying the responsible gene and the delineation of the pathogenesis of this developmental disorder.

  8. Reciprocal relations between perceived parental knowledge and adolescent substance use and delinquency: The moderating role of parent-teen relationship quality.

    PubMed

    Abar, Caitlin C; Jackson, Kristina M; Wood, Mark

    2014-09-01

    The current study prospectively examined hypothesized short- and long-term reciprocal relations between perceived parental knowledge and adolescent heavy episodic drinking, marijuana use, and delinquency. Using the contextual model of parenting style (Darling & Steinberg, 1993), we examined the extent to which the bidirectional nature of associations between knowledge and adolescent outcomes is dependent on a facet of parenting style: the quality of the parent-child relationship. Data came from the first 4 waves of the National Longitudinal Study of Youth 1997. The sample for the current study consisted of 5,419 students between 12 and 14 years of age at baseline (52% male) surveyed annually for 4 years. Parallel process, autoregressive latent trajectory models were used to examine relations between initial levels and change over time in perceived parental knowledge and adolescent risk, and short-term cross-lagged paths were included to examine bidirectionality while accounting for long-term associations. Results showed significant short-term and long-term bidirectionality between perceived parental knowledge and adolescent outcomes, with parent effects on students and student effects on parents. Long-term associations across constructs were negative, whereas short-term associations were positive. These reciprocal associations were shown to differ across levels of parent-child relationship quality with regard to adolescent heavy episodic drinking and delinquency, providing support for the contextual model of parenting style. Implications for future work on parent-child bidirectional relationships and parent-based interventions are discussed.

  9. Tunneling Time and Weak Measurement in Strong Field Ionization

    NASA Astrophysics Data System (ADS)

    Zimmermann, Tomáš; Mishra, Siddhartha; Doran, Brent R.; Gordon, Daniel F.; Landsman, Alexandra S.

    2016-06-01

    Tunneling delays represent a hotly debated topic, with many conflicting definitions and little consensus on when and if such definitions accurately describe the physical observables. Here, we relate these different definitions to distinct experimental observables in strong field ionization, finding that two definitions, Larmor time and Bohmian time, are compatible with the attoclock observable and the resonance lifetime of a bound state, respectively. Both of these definitions are closely connected to the theory of weak measurement, with Larmor time being the weak measurement value of tunneling time and Bohmian trajectory corresponding to the average particle trajectory, which has been recently reconstructed using weak measurement in a two-slit experiment [S. Kocsis, B. Braverman, S. Ravets, M. J. Stevens, R. P. Mirin, L. K. Shalm, and A. M. Steinberg, Science 332, 1170 (2011)]. We demonstrate a big discrepancy in strong field ionization between the Bohmian and weak measurement values of tunneling time, and we suggest this arises because the tunneling time is calculated for a small probability postselected ensemble of electrons. Our results have important implications for the interpretation of experiments in attosecond science, suggesting that tunneling is unlikely to be an instantaneous process.

  10. Cell adhesion and sorting in embryoid bodies derived from N- or E-cadherin deficient murine embryonic stem cells.

    PubMed

    Moore, Robert; Tao, Wensi; Meng, Yue; Smith, Elizabeth R; Xu, Xiang-Xi

    2014-02-15

    The primitive endoderm epithelial structure in mouse blastocysts forms following cell differentiation and subsequent sorting, and this two-step process can be reproduced in vitro using an embryoid body model. We found that in the chimeric embryoid bodies consisting of paired wildtype and E-cadherin null ES cells, the wildtype sorted to the center and were enveloped by the less adhesive E-cadherin null cells, in accord with Steinberg's hypothesis. However, wildtype and N-cadherin null ES cells intermixed and did not segregate, a situation that may be explained by Albert Harris' modified principle, which incorporates the unique properties of living cells. Furthermore, in chimeric embryoid bodies composed of N-cadherin and E-cadherin null ES cells, the two weakly interacting cell types segregated but did not envelop one another. Lastly, the most consistent and striking observation was that differentiated cells sorted to the surface and formed an enveloping layer, regardless of the relative cell adhesive affinity of any cell combination, supporting the hypothesis that the ability of the differentiated cells to establish apical polarity is the determining factor in surface sorting and positioning.

  11. Sensation Seeking and Online Gaming Addiction in Adolescents: A Moderated Mediation Model of Positive Affective Associations and Impulsivity.

    PubMed

    Hu, Jianping; Zhen, Shuangju; Yu, Chengfu; Zhang, Qiuyan; Zhang, Wei

    2017-01-01

    Based on the Dual Systems Model (Somerville et al., 2010; Steinberg, 2010a) and the biosocial-affect model (Romer and Hennessy, 2007) of adolescent sensation seeking and problem behaviors, the present study examined how (affective associations with online games as a mediator) and when (impulsivity as a moderator) did sensation seeking influence online gaming addiction in adolescence. A total of 375 Chinese male adolescents (mean age = 16.02 years, SD = 0.85) from southern China completed anonymous questionnaires regarding sensation seeking, positive affective associations with online games, impulsivity, and online gaming addiction. Our findings revealed that sensation seeking, positive affective associations with online games and impulsivity were each significantly and positively associated with online gaming addiction in adolescents. Positive affective associations mediated the relationship between sensation seeking and online gaming addiction. Further, impulsivity moderated the relationship between positive affective associations and online gaming addiction, such that the association between positive affective association and online gaming addiction was stronger for high than for low impulsivity adolescents. These findings underscore the importance of integrating the biosocial-affect model and the Dual Systems Model to understand how and when sensation seeking impacts adolescent online gaming addiction.

  12. The intelligibility of words, sentences, and continuous discourse using the articulation index

    NASA Astrophysics Data System (ADS)

    Depaolis, R. A.

    1992-10-01

    The purpose of this research was to investigate the effect of message redundancy upon intelligibility. The original methodology for the Articulation Index (AI) French and Steinberg, J. Acoust. Soc. Am., 19, 90-119, 1947 was used to examine the relation between words, meaningful sentences, and continuous discourse (CD). One primary consideration was to derive the relations between the three speech types with tightly controlled, highly repeatable experimental conditions such that any difference between them could be attributed solely to inherent contextual differences. One male speaker recorded 616 monosyllabic words, 176 meaningful speech perception in noise (SPIN) sentences, and 44 seventh-grade reading level CD passages. Twenty-four normal hearing subjects made intelligibility estimates of the CD and sentences and identified words at each of 44 conditions of filtering and signal-to-noise ratio. The sentence intelligibility scores and continuous discourse intelligibility scores plotted versus the AI (transfer function) were within 0.05 AI of each other. The word recognition scores were considerably lower for equivalent AI values of both sentences and CD.

  13. Vigorous Mantle Convection with a Very High Mid-mantle Viscosity

    NASA Astrophysics Data System (ADS)

    Jarvis, G. T.

    2015-12-01

    Two dimensional numerical models of mantle convection in a cylindrical shell are employed to investigate the impact of the very high viscosities in the lower mantle as proposed by Mitrovica and Forte (2004) and Steinberger and Calderwood (2006). Models are considered with and without mineral phase transitions. Our viscosity profiles are depth dependent with deep mantle viscosities increasing to values of 300 times the viscosity of the upper mantle and then decreasing dramatically on approaching the core-mantle boundary. Although phase transitions produce small secondary effects on the flow structure the main effect is that of the viscosity decrease near the core mantle boundary. Models with a high viscosity structure extending down to the core-mantle boundary are very sluggish with large aspect ratios, whereas models with a low viscosity just above the core mantle boundary overturn rapidly with aspect ratios close to unity. The latter models resemble uniformly low viscosity models despite the high viscosity region at mid-depths of the lower mantle.

  14. Modelling evolution of asteroid's rotation due to the YORP effect

    NASA Astrophysics Data System (ADS)

    Golubov, Oleksiy; Lipatova, Veronika; Scheeres, Daniel J.

    2016-05-01

    The Yarkovsky--O'Keefe--Radzievskii--Paddack (or YORP) effect is influence of light pressure on rotation of asteroids. It is the most important factor for evolution of rotation state of small asteroids, which can drastically alter their rotation rate and obliquity over cosmologic timescales.In the poster we present our program, which calculates evolution of ratation state of small asteroids subject to the YORP effect. The program accounts for both axial and obliquity components of YORP, takes into account the thermal inertia of the asteroid's soil, and the tangential YORP. The axial component of YORP is computed using the model by Steinberg and Sari (AJ, 141, 55). The thermal inertia is accounted for in the framework of Golubov et al. 2016 (MNRAS, stw540). Computation of the tangential YORP is based on a siple analytical model, whose applicability is verified via comparison to exact numeric simulations.We apply the program to different shape models of asteroids, and study coupled evolution of their rotation rate and obliquity.

  15. Sensation Seeking and Online Gaming Addiction in Adolescents: A Moderated Mediation Model of Positive Affective Associations and Impulsivity

    PubMed Central

    Hu, Jianping; Zhen, Shuangju; Yu, Chengfu; Zhang, Qiuyan; Zhang, Wei

    2017-01-01

    Based on the Dual Systems Model (Somerville et al., 2010; Steinberg, 2010a) and the biosocial-affect model (Romer and Hennessy, 2007) of adolescent sensation seeking and problem behaviors, the present study examined how (affective associations with online games as a mediator) and when (impulsivity as a moderator) did sensation seeking influence online gaming addiction in adolescence. A total of 375 Chinese male adolescents (mean age = 16.02 years, SD = 0.85) from southern China completed anonymous questionnaires regarding sensation seeking, positive affective associations with online games, impulsivity, and online gaming addiction. Our findings revealed that sensation seeking, positive affective associations with online games and impulsivity were each significantly and positively associated with online gaming addiction in adolescents. Positive affective associations mediated the relationship between sensation seeking and online gaming addiction. Further, impulsivity moderated the relationship between positive affective associations and online gaming addiction, such that the association between positive affective association and online gaming addiction was stronger for high than for low impulsivity adolescents. These findings underscore the importance of integrating the biosocial-affect model and the Dual Systems Model to understand how and when sensation seeking impacts adolescent online gaming addiction. PMID:28529494

  16. Revisiting the problem of Jewish bioethics: the case of terminal care.

    PubMed

    Barilan, Y Michael

    2003-06-01

    This paper examines the main Jewish sources relevant to end-of-life ethics, two Talmudic stories, the early modern code of law (Shulhan Aruch), and contemporary Halakhaic (religious law) responsa. Some Orthodox rabbis object to the use of artificial life support that prolongs the life of a dying patient and permit its active discontinuation when the patient is suffering. Other rabbis believe that every medical measure must be taken in order to prolong life. The context of the discussion is the most recent release of the "Steinberg Report," which proposes a law regulating end-of-life issues in Israel. It is argued that the Orthodox rabbis base their views on a strongly positivist concept of religious law. The rabbis deliberate the law as a manifestation of the will of God and try to stretch the law as much as possible in order to benefit the patient, even when it is good for the patient to die. Direct and active actions that kill are prohibited; certain forms of passive euthanasia and contrivances that terminate life support without needing direct human action are accepted.

  17. Tunneling Time and Weak Measurement in Strong Field Ionization.

    PubMed

    Zimmermann, Tomáš; Mishra, Siddhartha; Doran, Brent R; Gordon, Daniel F; Landsman, Alexandra S

    2016-06-10

    Tunneling delays represent a hotly debated topic, with many conflicting definitions and little consensus on when and if such definitions accurately describe the physical observables. Here, we relate these different definitions to distinct experimental observables in strong field ionization, finding that two definitions, Larmor time and Bohmian time, are compatible with the attoclock observable and the resonance lifetime of a bound state, respectively. Both of these definitions are closely connected to the theory of weak measurement, with Larmor time being the weak measurement value of tunneling time and Bohmian trajectory corresponding to the average particle trajectory, which has been recently reconstructed using weak measurement in a two-slit experiment [S. Kocsis, B. Braverman, S. Ravets, M. J. Stevens, R. P. Mirin, L. K. Shalm, and A. M. Steinberg, Science 332, 1170 (2011)]. We demonstrate a big discrepancy in strong field ionization between the Bohmian and weak measurement values of tunneling time, and we suggest this arises because the tunneling time is calculated for a small probability postselected ensemble of electrons. Our results have important implications for the interpretation of experiments in attosecond science, suggesting that tunneling is unlikely to be an instantaneous process.

  18. Organ printing: fiction or science.

    PubMed

    Jakab, Karoly; Neagu, Adrian; Mironov, Vladimir; Forgacs, Gabor

    2004-01-01

    Aggregates of living cells (i.e. model tissue fragments) under appropriate conditions fuse like liquid drops. According to Steinberg's differential adhesion hypothesis (DAH), this may be understood by assuming that cells are motile and tissues made of such cells possess an effective surface tension. Here we show that based on these properties three-dimensional cellular structures of prescribed shape can be constructed by a novel method: cell aggregate printing. Spherical aggregates of similar size made of cells with known adhesive properties were prepared. Aggregates were embedded into biocompatible gels. When the cellular and gel properties, as well as the symmetry of the initial configuration were appropriately adjusted the contiguous aggregates fused into ring-like organ structures. To elucidate the driving force and optimal conditions for this pattern formation, Monte Carlo simulations based on a DAH motivated model were performed. The simulations reproduced the experimentally observed cellular arrangements and revealed that the control parameter of pattern evolution is the gel-tissue interfacial tension, an experimentally accessible parameter.

  19. 2169 steel waveform measurements for equation of state and strength determination

    NASA Astrophysics Data System (ADS)

    Furnish, M. D.; Alexander, C. S.; Brown, J. L.; Reinhart, W. D.

    2014-01-01

    In support of efforts to develop multiscale models of a variety of materials, we have performed a set of eleven gas gun impact experiments on 2169 steel, a high-strength austenitic stainless steel. These experiments provided carefully controlled shock, reshock, and release velocimetry data, with initial shock stresses ranging from 10 to 50 GPa. Both windowed and free-surface measurements on samples ranging in thickness from 1 to 5 mm were made to increase the utility of the data set. Target physical phenomena included the elastic/plastic transition (Hugoniot elastic limit), the Hugoniot, any phase transition phenomena, and the release/reshock paths (windowed and free-surface), with associated strength information. The Hugoniot is nearly linear in US-up space. Reshock tests with explosively welded impactors produced clean results, by contrast with earlier reshock tests with glued impactors which showed gap signatures. The free-surface samples, which were steps on a single piece of steel, showed lower wavespeeds for thin (1 mm) samples than for thicker (2 or 4 mm) samples. A preliminary strength analysis suggests the flow strength increases with stress from ˜1 GPa to ˜2.5 GPa over this range, consistent with other recent work but about 25% above the Steinberg model.

  20. Activation of transient receptor potential vanilloid 1 by lipoxygenase metabolites depends on PKC phosphorylation.

    PubMed

    Kumar, Rakesh; Hazan, Adina; Geron, Matan; Steinberg, Rebbeca; Livni, Lital; Matzner, Henry; Priel, Avi

    2017-03-01

    Peripheral neuronal activation by inflammatory mediators is a multifaceted physiological response that involves a multitude of regulated cellular functions. One key pathway that has been shown to be involved in inflammatory pain is Gq/GPCR, whose activation by inflammatory mediators is followed by the regulated response of the cation channel transient receptor potential vanilloid 1 (TRPV1). However, the mechanism that underlies TRPV1 activation downstream of the Gq/GPCR pathway has yet to be fully defined. In this study, we employ pharmacological and molecular biology tools to dissect this activation mechanism via perforated-patch recordings and calcium imaging of both neurons and a heterologous system. We showed that TRPV1 activity downstream of Gq/GPCR activation only produced a subdued current, which was noticeably different from the robust current that is typical of TRPV1 activation by exogenous stimuli. Moreover, we specifically demonstrated that 2 pathways downstream of Gq/GPCR signaling, namely endovanilloid production by lipoxygenases and channel phosphorylation by PKC, converge on TRPV1 to evoke a tightly regulated response. Of importance, we show that only when both pathways are acting on TRPV1 is the inflammatory-mediated response achieved. We propose that the requirement of multiple signaling events allows subdued TRPV1 activation to evoke regulated neuronal response during inflammation.-Kumar R., Hazan, A., Geron, M., Steinberg, R., Livni, L., Matzner, H., Priel, A. Activation of transient receptor potential vanilloid 1 by lipoxygenase metabolites depends on PKC phosphorylation.

  1. Bilocal current densities and mean trajectories in a Young interferometer with two Gaussian slits and two detectors

    SciTech Connect

    Withers, L. P.; Narducci, F. A.

    2015-06-15

    The recent single-photon double-slit experiment of Steinberg et al., based on a weak measurement method proposed by Wiseman, showed that, by encoding the photon’s transverse momentum behind the slits into its polarization state, the momentum profile can subsequently be measured on average, from a difference of the separated fringe intensities for the two circular polarization components. They then integrated the measured average velocity field, to obtain the average trajectories of the photons enroute to the detector array. In this paper, we propose a modification of their experiment, to demonstrate that the average particle velocities and trajectories change when the mode of detection changes. The proposed experiment replaces a single detector by a pair of detectors with a given spacing between them. The pair of detectors is configured so that it is impossible to distinguish which detector received the particle. The pair of detectors is then analogous to the simple pair of slits, in that it is impossible to distinguish which slit the particle passed through. To establish the paradoxical outcome of the modified experiment, the theory and explicit three-dimensional formulas are developed for the bilocal probability and current densities, and for the average velocity field and trajectories as the particle wavefunction propagates in the volume of space behind the Gaussian slits. Examples of these predicted results are plotted. Implementation details of the proposed experiment are discussed.

  2. Free vascularised fibular grafting with OsteoSet®2 demineralised bone matrix versus autograft for large osteonecrotic lesions of the femoral head.

    PubMed

    Feng, Yong; Wang, Shanzhi; Jin, Dongxu; Sheng, Jiagen; Chen, Shengbao; Cheng, Xiangguo; Zhang, Changqing

    2011-04-01

    The aim of this study was to compare the safety and efficacy of OsteoSet®2 DBM with autologous cancellous bone in free vascularised fibular grafting for the treatment of large osteonecrotic lesions of the femoral head. Twenty-four patients (30 hips) with large osteonecrotic lesions of the femoral head (stage IIC in six hips, stage IIIC in 14, and stage IVC in ten, according to the classification system of Steinberg et al.) underwent free vascularised fibular grafting with OsteoSet®2 DBM. This group was retrospectively matched to a group of 24 patients (30 hips) who underwent free vascularised fibular grafting with autologous cancellous bone during the same time period according to the aetiology, stage, and size of the lesion and the mean preoperative Harris hip score. A prospective case-controlled study was then performed with a mean follow-up duration of 26 months. The results show no statistically significant differences between the two groups in overall clinical outcome or the radiographic assessment. Furthermore, no adverse events related to the use of the OsteoSet®2 DBM were observed. The results demonstrate that OsteoSet®2 DBM combined with autograft bone performs equally as well as that of autologous bone alone. Therefore, OsteoSet®2 DBM can be used as a safe and effective graft extender in free vascularised fibular grafting for large osteonecrotic lesions of the femoral head.

  3. Parental relationships, autonomy, and identity processes of high school students.

    PubMed

    Mullis, Ronald L; Graf, Shruti Chatterjee; Mullis, Ann K

    2009-12-01

    To examine the interrelations among parental relationships, emotional autonomy, and identity statuses, the authors asked 234 (105 male, 129 female) high school students to complete the Parental Bonding Scale (G. Parker, H. Tupling, & L. B. Brown, 1979), Emotional Autonomy Scale (L. D. Steinberg & S. B. Silverberg, 1986), and Extended Objective Measure of Ego Identity Scale-II (L. D. Bennion & G. R. Adams, 1986). There continues to be controversy about whether adolescents' identity formation is related to their emotional separation from their parents. According to Eriksonian and neo-Eriksonian theory (J. E. Marcia, 1980, 1984), adolescents who are successful in resolving their identity issues are better able to emotionally individuate from their parents. That is, adolescents have fewer conflicts with parents as they become more independent of them. Results of the present study indicate that adolescent perceptions of mother's caring behavior, but not father's caring behavior, predicted higher foreclosure identity status scores among adolescents. In addition, 2 dimensions of emotional autonomy (i.e., perceiving parents as people and parental deidealization) best predicted the adolescent identity statuses of moratorium and foreclosure. Results also indicate that future research may need to establish a better theoretical conceptualization of the constructs of interest in this study and better measures of emotional autonomy among adolescents.

  4. Are Superplumes a Myth?

    NASA Astrophysics Data System (ADS)

    Steinberger, Bernhard; Conrad, Clinton

    2017-04-01

    Two large seismically slow lower mantle regions beneath the Pacific and Africa are sometimes referred to as "superplumes". This names evokes associations of large-scale active upwellings, however it is not clear whether these are real, or rather just regular mantle plumes occur more frequently in these regions. Here we study the implications of new results on dynamic topography, which would be associated with active upwellings, on this question. Recently, Hoggard et al. (2016) developed a detailed model of marine residual topography, after subtracting isostatic crustal topography. Combining this with results from continents, a global model can be expanded in spherical harmonics. Comparison with dynamic topography derived from mantle flow models inferred from seismic tomography (Steinberger, 2016) yields overall good agreement and similar power spectra, except at spherical harmonic degree two where mantle flow models predict about six times as much power as is inferred from observations: Mantle flow models feature two large-scale antipodal upwellings at the seismically slow regions, whereas the actual topography gives only little indication of these. We will discuss here what this discrepancy could possibly mean and how it could be resolved.

  5. The Clinical Utility of CA 19-9 in Pancreatic Adenocarcinoma: Diagnostic and Prognostic Updates

    PubMed Central

    Poruk, Katherine E.; Gay, David Z.; Brown, Kurt; Mulvihill, Jeffrey D.; Boucher, Kenneth M.; Scaife, Courtney L.; Firpo, Matthew A.; Mulvihill, Sean J.

    2015-01-01

    CA 19-9 and CEA are the most commonly used biomarkers for diagnosis and management of patients with pancreatic cancer. Since the original compendium by Steinberg in 1990, numerous studies have reported the use of CA 19-9 and, to a lesser extent, CEA in the diagnosis of pancreatic cancer. Here we update an evaluation of the accuracy of CA 19-9 and CEA, and, unlike previous reviews, focus on discrimination between malignant and benign disease instead of normal controls. In 57 studies involving 3,285 pancreatic carcinoma cases, the combined sensitivity of CA 19-9 was 78.2% and in 37 studies involving 1,882 cases with benign pancreatic disease the specificity of CA 19-9 was 82.8%. From the combined analysis of studies reporting CEA, the sensitivity was 44.2% (1,324 cases) and the specificity was 84.8% (656 cases). These measurements more appropriately reflect the expected biomarker accuracy in the differential diagnosis of patients with periampullary diseases. We also present a summary of the use of CA 19-9 as a prognostic tool and evaluate CA 19-9 diagnostic and prognostic utility in a 10-year, single institution experience. PMID:23331006

  6. Integral group actions on symmetric spaces and discrete duality symmetries of supergravity theories

    SciTech Connect

    Carbone, Lisa; Murray, Scott H.; Sati, Hisham

    2015-10-15

    For G = G(ℝ), a split, simply connected, semisimple Lie group of rank n and K the maximal compact subgroup of G, we give a method for computing Iwasawa coordinates of K∖G using the Chevalley generators and the Steinberg presentation. When K∖G is a scalar coset for a supergravity theory in dimensions ≥3, we determine the action of the integral form G(ℤ) on K∖G. We give explicit results for the action of the discrete U-duality groups SL{sub 2}(ℤ) and E{sub 7}(ℤ) on the scalar cosets SO(2)∖SL{sub 2}(ℝ) and [SU(8)/( ± Id)]∖E{sub 7(+7)}(ℝ) for type IIB supergravity in ten dimensions and 11-dimensional supergravity reduced to D = 4 dimensions, respectively. For the former, we use this to determine the discrete U-duality transformations on the scalar sector in the Borel gauge and we describe the discrete symmetries of the dyonic charge lattice. We determine the spectrum-generating symmetry group for fundamental BPS solitons of type IIB supergravity in D = 10 dimensions at the classical level and we propose an analog of this symmetry at the quantum level. We indicate how our methods can be used to study the orbits of discrete U-duality groups in general.

  7. Techniques and Tools for Teaching the Photoelectric Effect

    NASA Astrophysics Data System (ADS)

    McKagan, S. B.; Handley, W.; Perkins, K. K.; Wieman, C. E.

    2006-12-01

    Understanding the photoelectric effect is a crucial step in understanding the particle nature of light, one of the foundations of quantum mechanics. The photoelectric effect is a powerful tool to help students build an understanding of the photon model of light, and to probe their understanding of the photon model. This topic, which may seem straightforward to physics professors, is treated only superficially in many courses in modern physics and quantum mechanics. However, research shows that students have serious difficulties understanding even the most basic aspects of the photoelectric effect, such as the experimental set-up, experimental results, and implications about the nature of light [1]. As part of a reformed modern physics course for engineering majors [2], we have created a research-based instructional unit on the photoelectric effect. This unit includes an interactive computer simulation [3], interactive lectures with peer instruction, and conceptual homework problems. Using common exam questions, we have found that our instruction leads to better student understanding than either traditional instruction or previous reformed instruction. [4] 1. R. N. Steinberg, G. E. Oberem, and L. C. McDermott, Am. J. Phys. 64, 1370 (1996). 2. S. B. McKagan, K. K. Perkins, and C. E. Wieman, PERC Proceedings 2006, in press; preprint available at http://arxiv.org/abs/physics/0608239 3. http://phet.colorado.edu/simulations/photoelectric/photoelectric.jnlp 4. This work was supported by NSF, The Kavli Institute, The Hewlett Foundation, and the University of Colorado.

  8. Modeling Propagation of Shock Waves in Metals

    SciTech Connect

    Howard, W M; Molitoris, J D

    2005-08-19

    We present modeling results for the propagation of strong shock waves in metals. In particular, we use an arbitrary Lagrange Eulerian (ALE3D) code to model the propagation of strong pressure waves (P {approx} 300 to 400 kbars) generated with high explosives in contact with aluminum cylinders. The aluminum cylinders are assumed to be both flat-topped and have large-amplitude curved surfaces. We use 3D Lagrange mechanics. For the aluminum we use a rate-independent Steinberg-Guinan model, where the yield strength and shear modulus depend on pressure, density and temperature. The calculation of the melt temperature is based on the Lindermann law. At melt the yield strength and shear modulus is set to zero. The pressure is represented as a seven-term polynomial as a function of density. For the HMX-based high explosive, we use a JWL, with a program burn model that give the correct detonation velocity and C-J pressure (P {approx} 390 kbars). For the case of the large-amplitude curved surface, we discuss the evolving shock structure in terms of the early shock propagation experiments by Sakharov.

  9. Discovery of a gene family critical to wyosine base formation in a subset of phenylalanine-specific transfer RNAs.

    PubMed

    Waas, William F; de Crécy-Lagard, Valérie; Schimmel, Paul

    2005-11-11

    A large number of post-transcriptional base modifications in transfer RNAs have been described (Sprinzl, M., Horn, C., Brown, M., Ioudovitch, A., and Steinberg, S. (1998) Nucleic Acids Res. 26, 148-153). These modifications enhance and expand tRNA function to increase cell viability. The intermediates and genes essential for base modifications in many instances remain unclear. An example is wyebutosine (yW), a fluorescent tricyclic modification of an invariant guanosine situated on the 3'-side of the tRNA(Phe) anticodon. Although biosynthesis of yW involves several reaction steps, only a single pathway-specific enzyme has been identified (Kalhor, H. R., Penjwini, M., and Clarke, S. (2005) Biochem. Biophys. Res. Commun. 334, 433-440). We used comparative genomics analysis to identify a cluster of orthologous groups (COG0731) of wyosine family biosynthetic proteins. Gene knock-out and complementation studies in Saccharomyces cerevisiae established a role for YPL207w, a COG0731 ortholog that encodes an 810-amino acid polypeptide. Further analysis showed the accumulation of N(1)-methylguanosine (m(1)G(37)) in tRNA from cells bearing a YPL207w deletion. A similar lack of wyosine base and build-up of m(1)G(37) is seen in certain mammalian tumor cell lines. We proposed that the 810-amino acid COG0731 polypeptide participates in converting tRNA(Phe)-m(1)G(37) to tRNA(Phe)-yW.

  10. Wave Refraction During the May 2002 Rarefaction Event

    NASA Astrophysics Data System (ADS)

    Smith, C. W.; Mullan, D. J.; Ness, N. F.; Skoug, R. M.

    2002-12-01

    In previous work [Smith et al., 2001] we examined IMF wave refraction during the May 1999 rarefaction interval known as ``The Day The Solar Wind Disappeared.'' On that day, Alfvén speeds remained elevated over an extended region. Analysis of the recorded ACE fields and plasma data revealed depressed magnetic fluctuation levels, reduced compression in the fluctuations, and a reduced wave-like component within the region of elevated Alfvén speed, all consistent with wave refraction. The May 2002 event provides a third such period (the second identified event occured 2 weeks prior to the May 1999 period) and it again demonstrates properties which are consistent with refraction. Smith, C.~W., D.~J. Mullan, N.~F. Ness, R.~M. Skoug, and J.~Steinberg, Day the solar wind almost disappeared: Magnetic field fluctuations, wave refraction and dissipation, J. Geophys. Res., A106, 18,625--18,634, 2001. Efforts at the Bartol Research Institute were supported by CIT subcontract PC251439 under NASA grant NAG5-6912 for support of the ACE magnetic field experiment and by the NASA Delaware Space College Grant. Work at Los Alamos was performed under the auspices of the U.S. Department of Energy with financial support from the NASA ACE program.

  11. Petrogenesis of Pliocene Alkaline Volcanic Rocks from Southeastern Styrian Basin, Austria

    NASA Astrophysics Data System (ADS)

    Ali, Sh.; Ntaflos, Th.

    2009-04-01

    Petrogenesis of Pliocene Alkaline Volcanic Rocks from Southeastern Styrian Basin, Austria Sh. Ali and Th. Ntaflos Dept. of Lithospheric Research, University of Vienna, Austria Neogene volcanism in the Alpine Pannonian Transition Zone occurred in a complex geodynamic setting. It can be subdivided into a syn-extentional phase that comprises Middle Miocene dominantly potassic, intermediate to acidic volcanism and a post-extensional phase, which is characterized by eruption of alkaline basaltic magmas during the Pliocene to Quartenary in the Styrian Basin. These alkaline basaltic magmas occur as small eruptive centers dominating the geomorphology of the southeastern part of the Styrian Basin. The eruptive centers along the SE Styrian Basin from North to South are: Oberpullendorf, Pauliberg, Steinberg, Strandenerkogel, Waltrafelsen and Klöch. The suite collected volcanic rocks comprise alkali basalts, basanites and nephelinites. Pauliberg: consists of alkali basalts that exhibit a narrow range of SiO2 (44.66-47.70 wt %) and wide range of MgO (8.52-13.19-wt %), are enriched in TiO2 (3.74-4.18 wt %). They are enriched in incompatible trace elements such as Zr (317-483 ppm), Nb (72.4-138 ppm) and Y (30.7-42 ppm). They have Nb/La ratio of 1.89 (average) and Cen/Ybn=15.22-23.11. Oberpullendorf: it also consists of alkali basalts with higher SiO2 (50.39 wt %) and lower TiO2 (2.80 wt %) if compared with the Pauliberg suite. Incompatible trace elements are lower than in Pauliberg; Zr =217 ppm, Nb=49.8 ppm, Y=23.6 ppm and Nb/La=1.93. The Oberpullendorf alkalibasalts are relative to Pauliberg lavas more depleted in LREE (Cen/Ybn=12.78). Steinberg: it consists of basanites with SiO2=44.49-46.85 wt %, MgO=6.30-9.13-wt %, and TiO2 =2.09-2.26 wt %. They are enriched in incompatible trace elements such as Zr (250-333 ppm), Nb (94-130 ppm), Y (24.7-31.9 ppm) and Nb/La=1.59 (average). The Cen/Ybn ratio varies between 18.17 and 22.83 indicating relative steep REE chondrite normalized

  12. Modeling Hemispheric Detonation Experiments in 2-Dimensions

    SciTech Connect

    Howard, W M; Fried, L E; Vitello, P A; Druce, R L; Phillips, D; Lee, R; Mudge, S; Roeske, F

    2006-06-22

    Experiments have been performed with LX-17 (92.5% TATB and 7.5% Kel-F 800 binder) to study scaling of detonation waves using a dimensional scaling in a hemispherical divergent geometry. We model these experiments using an arbitrary Lagrange-Eulerian (ALE3D) hydrodynamics code, with reactive flow models based on the thermo-chemical code, Cheetah. The thermo-chemical code Cheetah provides a pressure-dependent kinetic rate law, along with an equation of state based on exponential-6 fluid potentials for individual detonation product species, calibrated to high pressures ({approx} few Mbars) and high temperatures (20000K). The parameters for these potentials are fit to a wide variety of experimental data, including shock, compression and sound speed data. For the un-reacted high explosive equation of state we use a modified Murnaghan form. We model the detonator (including the flyer plate) and initiation system in detail. The detonator is composed of LX-16, for which we use a program burn model. Steinberg-Guinan models5 are used for the metal components of the detonator. The booster and high explosive are LX-10 and LX-17, respectively. For both the LX-10 and LX-17, we use a pressure dependent rate law, coupled with a chemical equilibrium equation of state based on Cheetah. For LX-17, the kinetic model includes carbon clustering on the nanometer size scale.

  13. Joe L. Kincheloe: Genies and wishes: a review of Key Works in Critical Pedagogy

    NASA Astrophysics Data System (ADS)

    Ali-Khan, Carolyne; Siry, Christina

    2012-06-01

    We review Key Works in Critical Pedagogy: Joe L. Kincheloe edited by kecia hayes, Shirley R. Steinberg and Kenneth Tobin, which gathers the seminal works of Joe. L. Kincheloe and pairs them with contemporary scholars who respond to and push forward Kincheloe's work. The chapters of Key Works in Critical Pedagogy are arranged to begin with Kincheloe's earlier works, going back to 1991, and progress through to the last works he published before his death in 2008. Through this format, readers are able to see the evolution of Kincheloe's scholarship. In addition to this, a few key authors provide a behind the scenes look at the man who wrote the texts. As Kincheloe's ideas and the ideas of the scholars that he drew from are presented, applied, reworked and reconfigured, they shift and transform. The response chapters work to (in effect) show us the notes in the margins of scholars who have been influenced by Kincheloe's ideas. Using the metaphors of lamps and wish-granting genies, we argue that this book is an important tool in illuminating the way forward for social justice work, published in an historical moment that requires precisely this.

  14. Fine tuning of tissues' viscosity and surface tension through contractility suggests a new role for α-catenin.

    PubMed

    Stirbat, Tomita Vasilica; Mgharbel, Abbas; Bodennec, Selena; Ferri, Karine; Mertani, Hichem C; Rieu, Jean-Paul; Delanoë-Ayari, Hélène

    2013-01-01

    What governs tissue organization and movement? If molecular and genetic approaches are able to give some answers on these issues, more and more works are now giving a real importance to mechanics as a key component eventually triggering further signaling events. We chose embryonic cell aggregates as model systems for tissue organization and movement in order to investigate the origin of some mechanical constraints arising from cells organization. Steinberg et al. proposed a long time ago an analogy between liquids and tissues and showed that indeed tissues possess a measurable tissue surface tension and viscosity. We question here the molecular origin of these parameters and give a quantitative measurement of adhesion versus contractility in the framework of the differential interfacial tension hypothesis. Accompanying surface tension measurements by angle measurements (at vertexes of cell-cell contacts) at the cell/medium interface, we are able to extract the full parameters of this model: cortical tensions and adhesion energy. We show that a tunable surface tension and viscosity can be achieved easily through the control of cell-cell contractility compared to cell-medium one. Moreover we show that α-catenin is crucial for this regulation to occur: these molecules appear as a catalyser for the remodeling of the actin cytoskeleton underneath cell-cell contact, enabling a differential contractility between the cell-medium and cell-cell interface to take place.

  15. The mechanics of cellular compartmentalization as a model for tumor spreading

    NASA Astrophysics Data System (ADS)

    Fritsch, Anatol; Pawlizak, Steve; Zink, Mareike; Kaes, Josef A.

    2012-02-01

    Based on a recently developed surgical method of Michael H"ockel, which makes use of cellular confinement to compartments in the human body, we study the mechanics of the process of cell segregation. Compartmentalization is a fundamental process of cellular organization and occurs during embryonic development. A simple model system can demonstrate the process of compartmentalization: When two populations of suspended cells are mixed, this mixture will eventually segregate into two phases, whereas mixtures of the same cell type will not. In the 1960s, Malcolm S. Steinberg formulated the so-called differential adhesion hypothesis which explains the segregation in the model system and the process of compartmentalization by differences in surface tension and adhesiveness of the interacting cells. We are interested in to which extend the same physical principles affect tumor growth and spreading between compartments. For our studies, we use healthy and cancerous breast cell lines of different malignancy as well as primary cells from human cervix carcinoma. We apply a set of techniques to study their mechanical properties and interactions. The Optical Stretcher is used for whole cell rheology, while Cell-cell-adhesion forces are directly measured with a modified AFM. In combination with 3D segregation experiments in droplet cultures we try to clarify the role of surface tension in tumor spreading.

  16. A V2O3-ordered mesoporous carbon composite with novel peroxidase-like activity towards the glucose colorimetric assay

    NASA Astrophysics Data System (ADS)

    Han, Lei; Zeng, Lingxing; Wei, Mingdeng; Li, Chang Ming; Liu, Aihua

    2015-07-01

    It is of great scientific and practical significance to explore inorganic mimetic enzymes to replace natural enzymes due to their instability and high cost. Herein we present an interesting discovery that a V2O3-ordered mesoporous carbon composite (V2O3-OMC) has a novel peroxidase-like activity towards fast redox reaction of typical peroxidase substrates H2O2 and 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS). Due to the small size effect and large surface area of V2O3 nanoparticles supported by OMC, V2O3-OMC exhibited excellent catalytic performance with a kcat of 1.28 × 104 s-1, KM (ABTS) of 0.067 mM and KM (H2O2) of 0.16 mM, and a significantly higher catalytic efficiency (kcat/KM) towards the oxidation of ABTS in comparison with the natural peroxidases. Furthermore, the Ping-pong BiBi mechanism was proposed to explain the catalytic reaction by V2O3-OMC. Based on this highly active biomimetic peroxidase and the colorimetric detection of H2O2, a facile analytical method was developed to detect glucose by using V2O3-OMC and glucose oxidase, which had a wide linear range (0.01-4 mM glucose), good selectivity and reliability for successful detection of various real samples. Thus, the novel V2O3-OMC peroxidase mimetic holds great promise for broad potential applications.It is of great scientific and practical significance to explore inorganic mimetic enzymes to replace natural enzymes due to their instability and high cost. Herein we present an interesting discovery that a V2O3-ordered mesoporous carbon composite (V2O3-OMC) has a novel peroxidase-like activity towards fast redox reaction of typical peroxidase substrates H2O2 and 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS). Due to the small size effect and large surface area of V2O3 nanoparticles supported by OMC, V2O3-OMC exhibited excellent catalytic performance with a kcat of 1.28 × 104 s-1, KM (ABTS) of 0.067 mM and KM (H2O2) of 0.16 mM, and a

  17. Bismuth-doped tin clusters: experimental and theoretical studies of neutral Zintl analogues.

    PubMed

    Heiles, Sven; Johnston, Roy L; Schäfer, Rolf

    2012-07-26

    The electron count of gas-phase clusters is increased gradually by element substitution in order to mimic the total number of electrons of known stable closo-clusters. A combination of elements from the fourth and fifth group of the periodic table such as Sn and Bi is well-suited for this approach. Hence, these small Sn-Bi clusters are investigated by employing the electric field deflection method. For clusters in the series Sn(M-N)Bi(N) (M = 5-13, N = 1-2), the beam profiles obtained in cryogenic experiments are dominated by beam broadening, indicating the presence of a permanent electric dipole moment that is sensitive to the (rigid) cluster structure. An intensive search for the global minimum structure employing a density functional theory/genetic algorithm method is performed. Dielectric properties for the identified low-energy isomers are computed. The structural and dielectric properties are used in beam profile simulations in order to discuss the experimental data. Comparison of theoretical and experimental results enables identification of the growing pattern of these small bimetallic clusters. For multiply doped clusters, it is concluded that the dopant atoms do not form direct Bi-Bi bonds, but more interestingly, a rearrangement of the cluster skeleton becomes apparent. The structural motifs are different from pure tin clusters but rather are rationalized using the corresponding structures of tin anions or are based on the Wade-Mingos concept. Further evidence for this idea is deduced from nuclear independent chemical shift calculations, which show nearly identical behavior for negatively charged pure and neutral bimetallic clusters. All of these findings are consistent with the idea of neutral Zintl analogues in the gas phase.

  18. Dissecting the Catalytic Mechanism of Betaine-Homocysteine S-Methyltransferase Using Intrinsic Tryptophan Fluorescence and Site-Directed Mutagenesis

    SciTech Connect

    Castro, C.; Gratson, A.A.; Evans, J.C.; Jiracek, J.; Collinsova, M.; Ludwig, M.L.; Garrow, T.A.

    2010-03-05

    Betaine-homocysteine S-methyltransferase (BHMT) is a zinc-dependent enzyme that catalyzes the transfer of a methyl group from glycine betaine (Bet) to homocysteine (Hcy) to form dimethylglycine (DMG) and methionine (Met). Previous studies in other laboratories have indicated that catalysis proceeds through the formation of a ternary complex, with a transition state mimicked by the inhibitor S-({delta}-carboxybutyl)-l-homocysteine (CBHcy). Using changes in intrinsic tryptophan fluorescence to determine the affinity of human BHMT for substrates, products, or CBHcy, we now demonstrate that the enzyme-substrate complex reaches its transition state through an ordered bi-bi mechanism in which Hcy is the first substrate to bind and Met is the last product released. Hcy, Met, and CBHcy bind to the enzyme to form binary complexes with K{sub d} values of 7.9, 6.9, and 0.28 {micro}M, respectively. Binary complexes with Bet and DMG cannot be detected with fluorescence as a probe, but Bet and DMG bind tightly to BHMT-Hcy to form ternary complexes with K{sub d} values of 1.1 and 0.73 {micro}M, respectively. Mutation of each of the seven tryptophan residues in human BHMT provides evidence that the enzyme undergoes two distinct conformational changes that are reflected in the fluorescence of the enzyme. The first is induced when Hcy binds, and the second, when Bet binds. As predicted by the crystal structure of BHMT, the amino acids Trp44 and Tyr160 are involved in binding Bet, and Glu159 in binding Hcy. Replacing these residues by site-directed mutagenesis significantly reduces the catalytic efficiency (V{sub max}/K{sub m}) of the enzyme. Replacing Tyr77 with Phe abolishes enzyme activity.

  19. Determination of the Structure and Catalytic Mechanism of Sorghum bicolor Caffeic Acid O-Methyltransferase and the Structural Impact of Three brown midrib12 Mutations1[W

    PubMed Central

    Green, Abigail R.; Lewis, Kevin M.; Barr, John T.; Jones, Jeffrey P.; Lu, Fachuang; Ralph, John; Vermerris, Wilfred; Sattler, Scott E.; Kang, ChulHee

    2014-01-01

    Using S-adenosyl-methionine as the methyl donor, caffeic acid O-methyltransferase from sorghum (Sorghum bicolor; SbCOMT) methylates the 5-hydroxyl group of its preferred substrate, 5-hydroxyconiferaldehyde. In order to determine the mechanism of SbCOMT and understand the observed reduction in the lignin syringyl-to-guaiacyl ratio of three brown midrib12 mutants that carry COMT gene missense mutations, we determined the apo-form and S-adenosyl-methionine binary complex SbCOMT crystal structures and established the ternary complex structure with 5-hydroxyconiferaldehyde by molecular modeling. These structures revealed many features shared with monocot ryegrass (Lolium perenne) and dicot alfalfa (Medicago sativa) COMTs. SbCOMT steady-state kinetic and calorimetric data suggest a random bi-bi mechanism. Based on our structural, kinetic, and thermodynamic results, we propose that the observed reactivity hierarchy among 4,5-dihydroxy-3-methoxycinnamyl (and 3,4-dihydroxycinnamyl) aldehyde, alcohol, and acid substrates arises from the ability of the aldehyde to stabilize the anionic intermediate that results from deprotonation of the 5-hydroxyl group by histidine-267. Additionally, despite the presence of other phenylpropanoid substrates in vivo, sinapaldehyde is the preferential product, as demonstrated by its low Km for 5-hydroxyconiferaldehyde. Unlike its acid and alcohol substrates, the aldehydes exhibit product inhibition, and we propose that this is due to nonproductive binding of the S-cis-form of the aldehydes inhibiting productive binding of the S-trans-form. The S-cis-aldehydes most likely act only as inhibitors, because the high rotational energy barrier around the 2-propenyl bond prevents S-trans-conversion, unlike alcohol substrates, whose low 2-propenyl bond rotational energy barrier enables rapid S-cis/S-trans-interconversion. PMID:24948836

  20. Kinetic and X-Ray Structural Evidence for Negative Cooperativity in Substrate Binding to Nicotinate Mononucleotide Adenylyltransferase (NMAT) from Bacillus anthracis

    SciTech Connect

    Sershon, Valerie C.; Santarsiero, Bernard D.; Mesecar, Andrew D.

    2009-08-07

    Biosynthesis of NAD(P) in bacteria occurs either de novo or through one of the salvage pathways that converge at the point where the reaction of nicotinate mononucleotide (NaMN) with ATP is coupled to the formation of nicotinate adenine dinucleotide (NaAD) and inorganic pyrophosphate. This reaction is catalyzed by nicotinate mononucleotide adenylyltransferase (NMAT), which is essential for bacterial growth, making it an attractive drug target for the development of new antibiotics. Steady-state kinetic and direct binding studies on NMAT from Bacillus anthracis suggest a random sequential Bi-Bi kinetic mechanism. Interestingly, the interactions of NaMN and ATP with NMAT were observed to exhibit negative cooperativity, i.e. Hill coefficients <1.0. Negative cooperativity in binding is supported by the results of X-ray crystallographic studies. X-ray structures of the B. anthracis NMAT apoenzyme, and the NaMN- and NaAD-bound complexes were determined to resolutions of 2.50 A, 2.60 A and 1.75 A, respectively. The X-ray structure of the NMAT-NaMN complex revealed only one NaMN molecule bound in the biological dimer, supporting negative cooperativity in substrate binding. The kinetic, direct-binding, and X-ray structural studies support a model in which the binding affinity of substrates to the first monomer of NMAT is stronger than that to the second, and analysis of the three X-ray structures reveals significant conformational changes of NMAT along the enzymatic reaction coordinate. The negative cooperativity observed in B. anthracis NMAT substrate binding is a unique property that has not been observed in other prokaryotic NMAT enzymes. We propose that regulation of the NAD(P) biosynthetic pathway may occur, in part, at the reaction catalyzed by NMAT.

  1. Characterization of the kinetics of cardiac cytosolic malate dehydrogenase and comparative analysis of cytosolic and mitochondrial isoforms.

    PubMed

    Dasika, Santosh K; Vinnakota, Kalyan C; Beard, Daniel A

    2015-01-20

    Because the mitochondrial inner membrane is impermeable to pyridine nucleotides, transport of reducing equivalents between the mitochondrial matrix and the cytoplasm relies on shuttle mechanisms, including the malate-aspartate shuttle and the glycerol-3-phosphate shuttle. These shuttles are needed for reducing equivalents generated by metabolic reactions in the cytosol to be oxidized via aerobic metabolism. Two isoenzymes of malate dehydrogenase (MDH) operate as components of the malate-aspartate shuttle, in which a reducing equivalent is transported via malate, which when oxidized to oxaloacetate, transfers an electron pair to reduce NAD to NADH. Several competing mechanisms have been proposed for the MDH-catalyzed reaction. This study aims to identify the pH-dependent kinetic mechanism for cytoplasmic MDH (cMDH) catalyzed oxidation/reduction of MAL/OAA. Experiments were conducted assaying the forward and reverse directions with products initially present, varying pH between 6.5 and 9.0. By fitting time-course data to various mechanisms, it is determined that an ordered bi-bi mechanism with coenzyme binding first followed by the binding of substrate is able to explain the kinetic data. The proposed mechanism is similar to, but not identical to, the mechanism recently determined for the mitochondrial isoform, mMDH. cMDH and mMDH mechanisms are also shown to both be reduced versions of a common, more complex mechanism that can explain the kinetic data for both isoforms. Comparing the simulated activity (ratio of initial velocity to the enzyme concentration) under physiological conditions, the mitochondrial MDH (mMDH) activity is predicted to be higher than cMDH activity under mitochondrial matrix conditions while the cMDH activity is higher than mMDH activity under cytoplasmic conditions, suggesting that the functions of the isoforms are kinetically tuned to their individual physiological roles.

  2. The Ternary Alkaline-Earth Metal Manganese Bismuthides Sr2MnBi2 and Ba2Mn1-xBi2 (x ≈ 0.15).

    PubMed

    Ovchinnikov, Alexander; Saparov, Bayrammurad; Xia, Sheng-Qing; Bobev, Svilen

    2017-10-02

    Two new ternary manganese bismuthides have been synthesized and their structures established based on single-crystal X-ray diffraction methods. Sr2MnBi2 crystallizes in the orthorhombic space group Pnma (a = 16.200(9) Å, b = 14.767(8) Å, c = 8.438(5) Å, V = 2018(2) Å(3); Z = 12; Pearson index oP60) and is isostructural to the antimonide Sr2MnSb2. The crystal structure contains corrugated layers of corner- and edge-shared [MnBi4] tetrahedra and Sr atoms enclosed between these layers. Electronic structure calculations suggest that Sr2MnBi2 is a magnetic semiconductor possessing Mn(2+) (high-spin d(5)) ions, and its structure can be rationalized within the Zintl concept as [Sr(2+)]2[Mn(2+)][Bi(3-)]2. The temperature dependence of the resistivity shows behavior consistent with a degenerate semiconductor/poor metal, and magnetic susceptibility measurements reveal a high degree of frustration resulting from the two-dimensional nature of the structure. The compositionally similar Ba2Mn1-xBi2 (x ≈ 0.15) crystallizes in a very different structure (space group Imma, a = 25.597(8) Å, b = 25.667(4) Å, c = 17.128(3) Å, V = 11253(4) Å(3); Z = 64; Pearson index oI316) with its own structure type. The complex structure boasts Mn atoms in a variety of coordination environments and can be viewed as consisting of two interpenetrating 3D frameworks, linked by Bi-Bi bonds. Ba2Mn1-xBi2 can be regarded as a highly reduced compound with anticipated metallic behavior.

  3. Enhancement of Er optical efficiency through bismuth sensitization in yttrium oxide

    SciTech Connect

    Scarangella, Adriana; Reitano, Riccardo; Franzò, Giorgia; Miritello, Maria; Priolo, Francesco

    2015-07-27

    The process of energy transfer (ET) between optically active ions has been widely studied to improve the optical efficiency of a system for different applications, from lighting and photovoltaics to silicon microphotonics. In this work, we report the influence of Bi on the Er optical emission in erbium-yttrium oxide thin films synthesized by magnetron co-sputtering. We demonstrate that this host permits to well dissolve Er and Bi ions, avoiding their clustering, and thus to stabilize the optically active Er{sup 3+} and Bi{sup 3+} valence states. In addition, we establish the ET occurrence from Bi{sup 3+} to Er{sup 3+} by the observed Bi{sup 3+} PL emission decrease and the simultaneous Er{sup 3+} photoluminescence (PL) emission increase. This was further confirmed by the coincidence of the Er{sup 3+} and Bi{sup 3+} excitation bands, analyzed by PL excitation spectroscopy. By increasing the Bi content of two orders of magnitude inside the host, though the occurrence of Bi-Bi interactions becomes deleterious for Bi{sup 3+} optical efficiency, the ET process between Bi{sup 3+} and Er{sup 3+} is still prevalent. We estimate ET efficiency of 70% for the optimized Bi:Er ratio equal to 1:3. Moreover, we have demonstrated to enhance the Er{sup 3+} effective excitation cross section by more than three orders of magnitude with respect to the direct one, estimating a value of 5.3 × 10{sup −18} cm{sup 2}, similar to the expected Bi{sup 3+} excitation cross section. This value is one of the highest obtained for Er in Si compatible hosts. These results make this material very promising as an efficient emitter for Si-compatible photonics devices.

  4. Remaining challenges in cellular flavin cofactor homeostasis and flavoprotein biogenesis

    NASA Astrophysics Data System (ADS)

    Giancaspero, Teresa Anna; Colella, Matilde; Brizio, Carmen; Difonzo, Graziana; Fiorino, Giuseppina Maria; Leone, Piero; Brandsch, Roderich; Bonomi, Francesco; Iametti, Stefania; Barile, Maria

    2015-04-01

    The primary role of the water-soluble vitamin B2 (riboflavin) in cell biology is connected with its conversion into FMN and FAD, the cofactors of a large number of dehydrogenases, oxidases and reductases involved in energetic metabolism, epigenetics, protein folding, as well as in a number of diverse regulatory processes. The problem of localisation of flavin cofactor synthesis events and in particular of the FAD synthase (EC 2.7.7.2) in HepG2 cells is addressed here by confocal microscopy in the frame of its relationships with kinetics of FAD synthesis and delivery to client apo-flavoproteins. FAD synthesis catalysed by recombinant isoform 2 of FADS occurs via an ordered bi-bi mechanism in which ATP binds prior to FMN, and pyrophosphate is released before FAD. Spectrophotometric continuous assays of the reconstitution rate of apo-D-aminoacid oxidase with its cofactor, allowed us to propose that besides its FAD synthesising activity, hFADS is able to operate as a FAD "chaperone". The physical interaction between FAD forming enzyme and its clients was further confirmed by dot blot and immunoprecipitation experiments carried out testing as a client either a nuclear or a mitochondrial enzyme that is lysine specific demethylase 1 (LSD1, EC 1.-.-.-) and dimethylglycine dehydrogenase (Me2GlyDH, EC 1.5.8.4), respectively which carry out similar reactions of oxidative demethylation, assisted by tetrahydrofolate used to form 5,10-methylene-tetrahydrofolate. A direct transfer of the cofactor from hFADS2 to apo-dimethyl glycine dehydrogenase was also demonstrated. Thus, FAD synthesis and delivery to these enzymes are crucial processes for bioenergetics and nutri-epigenetics of liver cells.

  5. Structural basis for substrate specificity differences of horse liver alcohol dehydrogenase isozymes.

    PubMed

    Adolph, H W; Zwart, P; Meijers, R; Hubatsch, I; Kiefer, M; Lamzin, V; Cedergren-Zeppezauer, E

    2000-10-24

    A structure determination in combination with a kinetic study of the steroid converting isozyme of horse liver alcohol dehydrogenase, SS-ADH, is presented. Kinetic parameters for the substrates, 5beta-androstane-3beta,17beta-ol, 5beta-androstane-17beta-ol-3-one, ethanol, and various secondary alcohols and the corresponding ketones are compared for the SS- and EE-isozymes which differ by nine amino acid substitutions and one deletion. Differences in substrate specificity and stereoselectivity are explained on the basis of individual kinetic rate constants for the underlying ordered bi-bi mechanism. SS-ADH was crystallized in complex with 3alpha,7alpha,12alpha-trihydroxy-5beta-cholan -24-acid (cholic acid) and NAD(+), but microspectrophotometric analysis of single crystals proved it to be a mixed complex containing 60-70% NAD(+) and 30-40% NADH. The crystals belong to the space group P2(1) with cell dimensions a = 55.0 A, b = 73.2 A, c = 92.5 A, and beta = 102.5 degrees. A 98% complete data set to 1.54-A resolution was collected at 100 K using synchrotron radiation. The structure was solved by the molecular replacement method utilizing EE-ADH as the search model. The major structural difference between the isozymes is a widening of the substrate channel. The largest shifts in C(alpha) carbon positions (about 5 A) are observed in the loop region, in which a deletion of Asp115 is found in the SS isozyme. SS-ADH easily accommodates cholic acid, whereas steroid substrates of similar bulkiness would not fit into the EE-ADH substrate site. In the ternary complex with NAD(+)/NADH, we find that the carboxyl group of cholic acid ligates to the active site zinc ion, which probably contributes to the strong binding in the ternary NAD(+) complex.

  6. The enzymology of alanine aminotransferase (AlaAT) isoforms from Hordeum vulgare and other organisms, and the HvAlaAT crystal structure.

    PubMed

    Duff, Stephen M G; Rydel, Timothy J; McClerren, Amanda L; Zhang, Wenlan; Li, Jimmy Y; Sturman, Eric J; Halls, Coralie; Chen, Songyang; Zeng, Jiamin; Peng, Jiexin; Kretzler, Crystal N; Evdokimov, Artem

    2012-12-01

    In this paper we describe the expression, purification, kinetics and biophysical characterization of alanine aminotransferase (AlaAT) from the barley plant (Hordeum vulgare). This dimeric PLP-dependent enzyme is a pivotal element of several key metabolic pathways from nitrogen assimilation to carbon metabolism, and its introduction into transgenic plants results in increased yield. The enzyme exhibits a bi-bi ping-pong reaction mechanism with a K(m) for alanine, 2-oxoglutarate, glutamate and pyruvate of 3.8, 0.3, 0.8 and 0.2 mM, respectively. Barley AlaAT catalyzes the forward (alanine-forming) reaction with a k(cat) of 25.6 s(-1), the reverse (glutamate-forming) reaction with k(cat) of 12.1 s(-1) and an equilibrium constant of ~0.5. The enzyme is also able to utilize aspartate and oxaloacetate with ~10% efficiency as compared to the native substrates, which makes it much more specific than related bacterial/archaeal enzymes (that also have lower K(m) values). We have crystallized barley AlaAT in complex with PLP and l-cycloserine and solved the structure of this complex at 2.7 Å resolution. This is the first example of a plant AlaAT structure, and it reveals a canonical aminotransferase fold similar to structures of the Thermotoga maritima, Pyrococcus furiosus, and human enzymes. This structure bridges our structural understanding of AlaAT mechanism between three kingdoms of life and allows us to shed some light on the specifics of the catalysis performed by these proteins.

  7. A qualitative study of community perceptions about childhood diarrhea and its management in Assosa District, West Ethiopia.

    PubMed

    Yalew, Estifanos

    2014-09-19

    Diarrhea control programs require evidences on factors which influence the caregiver's treatment of illness. Thus, understanding the caregiver's perception of the causes and management of diarrhea is very essential to plan effective prevention and control measures. This study aimed to explore their perceptions towards the causes and management of childhood diarrhea in Assosa district, West Ethiopia. Qualitative research methods were employed among caregivers who reside in two villages (Amba 4 and Selga 22) of the district. The villages were selected purposively and all eligible participants were identified with the help of village leaders and health extension workers. Then, in-depth interviews and focus group discussions were used to collect data from the participants. For this purpose, a semi-structured interview checklist and discussion guides were prepared. Data was collected by experienced and trained sociologists and public health professionals. The collected data was translated and analyzed thematically. No software was used. Majority of the caregivers perceived inadequate personal hygiene and poor environmental sanitation as the main causes of childhood diarrhea. However, few of them related its occurrence with sucking hot breast milk. On the other side, homemade management of diarrhea was commonly practiced in the community, i.e. providing boiled and cooled water with honey and Haile Sellasie silver coin [Mariatriza]. However, indigenous communities preferred traditional medications such as Sirsafe, Bibi and Kebercho to their children when they got diarrhea. Childhood diarrhea was perceived as the commonest disease in the community. Consequently, diverse misperceptions and malpractices on the causes and management of the problem existed. Thus, urgent effective interventions that consider the local culture and resources should be designed.

  8. Kinetic, Thermodynamic, and Structural Insight into the Mechanism of Phosphopantetheine Adenylyltransferase from Mycobacterium tuberculosis

    SciTech Connect

    Wubben, Thomas J.; Mesecar, Andrew D.

    2012-05-29

    Phosphopantetheine adenylyltransferase (PPAT) catalyzes the penultimate step in the coenzyme A (CoA) biosynthetic pathway, reversibly transferring an adenylyl group from ATP to 4'-phosphopantetheine (PhP) to form dephosphocoenzyme A. This reaction sits at the branch point between the de novo pathway and the salvage pathway, and has been shown to be a rate-limiting step in the biosynthesis of CoA. Importantly, bacterial and mammalian PPATs share little sequence homology, making the enzyme a potential target for antibiotic development. A series of steady-state kinetic, product inhibition, and direct binding studies with Mycobacterium tuberculosis PPAT (MtPPAT) was conducted and suggests that the enzyme utilizes a nonrapid-equilibrium random bi-bi mechanism. The kinetic response of MtPPAT to the binding of ATP was observed to be sigmoidal under fixed PhP concentrations, but substrate inhibition was observed at high PhP concentrations under subsaturating ATP concentrations, suggesting a preferred pathway to ternary complex formation. Negative cooperativity in the kinetic response of MtPPAT to PhP binding was observed under certain conditions and confirmed thermodynamically by isothermal titration calorimetry, suggesting the formation of an asymmetric quaternary structure during sequential ligation of substrates. Asymmetry in binding was also observed in isothermal titration calorimetry experiments with dephosphocoenzyme A and CoA. X-ray structures of MtPPAT in complex with PhP and the nonhydrolyzable ATP analogue adenosine-5'-[({alpha},{beta})-methyleno]triphosphate were solved to 1.57 {angstrom} and 2.68 {angstrom}, respectively. These crystal structures reveal small conformational changes in enzyme structure upon ligand binding, which may play a role in the nonrapid-equilibrium mechanism. We suggest that the proposed kinetic mechanism and asymmetric character in MtPPAT ligand binding may provide a means of reaction and pathway regulation in addition to that of the

  9. Putrescine N-Methyltransferase in Cultured Roots of Hyoscyamus albus1

    PubMed Central

    Hibi, Naruhiro; Fujita, Toshihiro; Hatano, Mika; Hashimoto, Takashi; Yamada, Yasuyuki

    1992-01-01

    Biosynthesis of tropane alkaloids is thought to proceed by way of the diamine putrescine, followed by its methylation by putrescine N-methyltransferase (PMT; EC 2.1.1.53). High PMT activities were found in branch roots and/or cultured roots of several solanaceous plants. PMT was partially purified and characterized from cultured roots of Hyoscyamus albus that contain hyoscyamine as the main alkaloid. Initial velocity studies and product inhibition patterns of PMT are consistent with an ordered bi-bi mechanism, in which the Km values for putrescine and S-adenosyl-l-methionine are 277 and 203 μm, respectively, and the Ki value for S-adenosyl-l-homocysteine is 110 μm. PMT efficiently N-methylated amines that have at least two amino groups separated by three or four methylene groups. Monoamines were good competitive inhibitors of PMT, among which n-butylamine, cyclohexylamine, and exo-2-aminonorbornane were most inhibitory, with respective Ki values of 11.0, 9.1, and 10.0 μm. When n-butylamine was fed to root cultures of H. albus, the alkamine intermediates (tropinone, tropine, and pseudotropine) drastically decreased at 1 mm of the exogenous monoamine, and the hyoscyamine content decreased by 52% at 6 mm, whereas the contents of 6β-hydroxyhyoscyamine and scopolamine did not change. Free and conjugated forms of polyamines were also measured. The n-butylamine treatment caused a large increase in the putrescine content (especially in the conjugated pool), and the spermine content also increased slightly, whereas the spermidine content decreased slightly. The increase in the putrescine pool size (approximately 40 nmol/mg dry weight) was large enough to account for the decrease in the total alkaloid pool size. Similar results were also obtained in root cultures of Datura stramonium. These studies further support the role of PMT as the first committed enzyme specific to alkaloid biosynthesis. Images Figure 8 PMID:16653064

  10. Structural elucidation of the Bi(2(n + 2))Mo(n)O(6(n + 1)) (n = 3, 4, 5 and 6) family of fluorite superstructures by transmission electron microscopy.

    PubMed

    Landa-Cánovas, Angel R; Vila, Eladio; Hernández-Velasco, Jorge; Galy, Jean; Castro, Alicia

    2009-08-01

    The cationic framework structure of a whole new family of compounds with the general formula Bi(2(n + 2))Mo(n)O(6(n + 1)) (n = 3, 4, 5 and 6) has been elucidated by transmission electron microscopy (TEM) methods. High-resolution transmission electron microscopy (HRTEM) has been used to postulate heavy-atom models based on the known structure of the n = 3 phase, Bi(10)Mo(3)O(24). These models were tested by HRTEM image simulation, electron diffraction and powder X-ray diffraction simulation methods which agreed with the experimental results. The four known phases of this family correspond to n = 3, 4, 5 and 6 members and all show fluorite superstructures. They consist of a common delta-Bi(2)O(3) fluorite-type framework, inside of which are distributed ribbons of {MoO(4)} tetrahedra which are infinite along b, one tetrahedron thick along c, and of variable widths of 3, 4, 5 or 6 {MoO(4)} tetrahedra along a depending on the family member (n value). These {MoO(4)} tetrahedra are isolated, i.e. without sharing any corner as in the [Bi(12)O(14)] columnar structural-type phase Bi[Bi(12)O(14)][MoO(4)](4)[VO(4)]. The structure of all these family members can be described as crystallographic shear derivatives from Aurivillius-type phases such as Bi(2)MoO(6), the n = infinity end member. All these compounds are good oxygen-ion conductors.

  11. Kinetics of acyl transfer reactions in organic media catalysed by Candida antarctica lipase B.

    PubMed

    Martinelle, M; Hult, K

    1995-09-06

    The acyl transfer reactions catalysed by Candida antartica lipase B in organic media followed a bi-bi ping-pong mechanism, with competitive substrate inhibition by the alcohols used as acyl acceptors. The effect of organic solvents on Vm and Km was investigated. The Vm values in acetonitrile was 40-50% of those in heptane. High Km values in acetonitrile compared to those in heptane could partly be explained by an increased solvation of the substrates in acetonitrile. Substrate solvation caused a 10-fold change in substrate specificity, defined as (Vm/Km)ethyl octanoate/(Vm/Km)octanoic acid, going from heptane to acetonitrile. Deacylation was the rate determining step for the acyl transfer in heptane with vinyl- and ethyl octanoate as acyl donors and (R)-2-octanol as acyl acceptor. With 1-octanol, a rate determining deacylation step in heptane was indicated using the same acyl donors. Using 1-octanol as acceptor in heptane, S-ethyl thiooctanoate had a 25- to 30-fold lower Vm/Km value and vinyl octanoate a 4-fold higher Vm/Km value than that for ethyl octanoate. The difference showed to be a Km effect for vinyl octanoate and mainly a Km effect for S-ethyl thiooctanoate. The Vm values of the esterification of octanoic acid with different alcohols was 10-30-times lower than those for the corresponding transesterification of ethyl octanoate. The low activity could be explained by a low pH around the enzyme caused by the acid or a withdrawing of active enzyme by nonproductive binding by the acid.

  12. The effect of thermodynamic properties of solvent mixtures explains the difference between methanol and ethanol in C.antarctica lipase B catalyzed alcoholysis.

    PubMed

    Sasso, Francesco; Kulschewski, Tobias; Secundo, Francesco; Lotti, Marina; Pleiss, Jürgen

    2015-11-20

    Kinetic modelling, molecular modelling, and experimental determination of the initial reaction velocity of lipase-catalyzed alcoholysis were combined to study the effect of the alcohol substrate to catalytic activity. The model system consisted of methanol or ethanol at varying concentrations, vinyl acetate as ester substrate 15.2% (v/v), toluene as organic solvent, water at a controlled thermodynamic activity of 0.09, and C. antarctica lipase B as enzyme. For both alcohol substrates, the initial reaction velocity increased sharply at low concentrations and reached a maximum at 0.7% (v/v) for methanol and 2% (v/v) for ethanol. For higher concentrations, the reaction rate decreased to a level of 74% and 60% of the peak value, respectively, due to substrate inhibition. The concentration dependency was described by a kinetic model, including a ping-pong bi-bi mechanism and competitive inhibition by the alcohol, and confirmed previous observations that methanol is more efficiently inhibiting the enzyme than ethanol. However, if the initial reaction velocity was expressed in terms of thermodynamic activity of the two alcohol substrates, the maximum of initial reaction velocity was similar for methanol (a MeOH(max)=0.19) and ethanol (a EtOH(max)=0.21). This was confirmed by molecular modelling which resulted in similar KM (0.22 and 0.19) and Ki values (0.44 and 0.49) for methanol and ethanol, respectively, if expressed in thermodynamic activities. Thus, the experimentally observed difference between methanol and ethanol is not due to differences in interaction with the enzyme but is a consequence of the thermodynamics of the substrate-solvent mixture. For low concentrations in toluene, the activity coefficient of methanol is 40% higher than the activity coefficient of ethanol (γ MeOH=8.5, γ EtOH=6.1). Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Biocatalytic process optimization based on mechanistic modeling of cholic acid oxidation with cofactor regeneration.

    PubMed

    Braun, Michael; Link, Hannes; Liu, Luo; Schmid, Rolf D; Weuster-Botz, Dirk

    2011-06-01

    Reduction and oxidation of steroids in the human gut are catalyzed by hydroxysteroid dehydrogenases of microorganisms. For the production of 12-ketochenodeoxycholic acid (12-Keto-CDCA) from cholic acid the biocatalytic application of the 12α-hydroxysteroid dehydrogenase of Clostridium group P, strain C 48-50 (HSDH) is an alternative to chemical synthesis. However, due to the intensive costs the necessary cofactor (NADP(+) ) has to be regenerated. The alcohol dehydrogenase of Thermoanaerobacter ethanolicus (ADH-TE) was applied to catalyze the reduction of acetone while regenerating NADP(+) . A mechanistic kinetic model was developed for the process development of cholic acid oxidation using HSDH and ADH-TE. The process model was derived by identifying the parameters for both enzymatic models separately using progress curve measurements of batch processes over a broad range of concentrations and considering the underlying ordered bi-bi mechanism. Both independently derived kinetic models were coupled via mass balances to predict the production of 12-Keto-CDCA with HSDH and integrated cofactor regeneration with ADH-TE and acetone as co-substrate. The prediction of the derived model was suitable to describe the dynamics of the preparative 12-Keto-CDCA batch production with different initial reactant and enzyme concentrations. These datasets were used again for parameter identification. This led to a combined model which excellently described the reaction dynamics of biocatalytic batch processes over broad concentration ranges. Based on the identified process model batch process optimization was successfully performed in silico to minimize enzyme costs. By using 0.1 mM NADP(+) the HSDH concentration can be reduced to 3-4 µM and the ADH concentration to 0.4-0.6 µM to reach the maximal possible conversion of 100 mM cholic acid within 48 h. In conclusion, the identified mechanistic model offers a powerful tool for a cost-efficient process design. Copyright © 2010 Wiley

  14. Sorbitol production in charged membrane bioreactor with coenzyme regeneration system: II. Theoretical analysis of a continuous reaction with retained and regenerated NADPH.

    PubMed

    Ikemi, M; Ishimatsu, Y; Kise, S

    1990-06-20

    A theoretical model was constructed in order to study charged membrane bioreactors (CMBRs). In this model, it was postulated that a native nicotinamide coenzyme NADP(H) can be partially retained by a charged membrane in continuous operation. A multienzyme system composed of NADPH-dependent aldose reductase (AR) and glucose dehydrogenase (GDH) was used for the production of sorbitol and gluconic acid from glucose and for the conjugated enzymatic regeneration of NADP(H). Both enzymes were studied with respect to their reaction kinetics. AR was determined to obey the Theorell-Chance mechanism. GDH reaction was approximated by the initial velocity equation of the sequential Bi-Bi mechanism since the reverse reaction could be neglected. Significant inhibitions of both enzymes by sorbitol, gluconic acid, and glucose were observed, and the mode of inhibition was estimated to modify the velocity equations. The differential equation system for each component was derived and numerically analyzed according to the model. The theoretical model elucidated several features of the CMBR. (1) When compared at the same productivity, higher retainment was found to bring about a higher coenzyme turnover number, indicating that the feed coenzyme concentration can be reduced. (2) Under constant conversion, a contradictory relationship between turnover number and residence time arises if the feed concentration of a coenzyme varies. The theoretical model predicts that there is a practically optimal concentration for using NADP(H) efficiently. This concentration was consistent with that yielding the estimated minimum total cost. (3) In this system, excess-GDH-to-AR activity was required because of differences in their kinetic constants. The amount of regeneration enzyme required can be reduced by the accumulation of excels NADPH due to coenzyme retainment. (4) Comparison with an ideal repeated batch reaction revealed that the continuously operated CMBR was vastly superior with respect to

  15. RVB states in doped band insulators from Coulomb forces: theory and a case study of superconductivity in BiS2 layers

    NASA Astrophysics Data System (ADS)

    Baskaran, G.

    2016-12-01

    Doped band insulators, HfNCl, WO3, diamond, Bi2Se3, BiS2 families, STO/LAO interface, gate doped SrTiO3, MoS2 and so on are unusual superconductors. With an aim to build a general theory for superconductivity in doped band insulators, we focus on the BiS2 family which was discovered by Mizuguchi et al in 2012. While maximum Tc is only ˜11 K in {{LaO}}1-{{x}}{{{F}}}{{x}}{{BiS}}2, a number of experimental results are puzzling and anomalous in the sense that they resemble high T c and unconventional superconductors. Using a two orbital model of Usui, Suzuki and Kuroki, we show that the uniform low density free Fermi sea in {{LaO}}{0,5}{{{F}}}0.5{{BiS}}2 is unstable towards formation of the next nearest neighbor Bi-S-Bi diagonal valence bond (charged -2e Cooper pair) and their Wigner crystallization. Instability to this novel state of matter is caused by unscreened nearest neighbor coulomb repulsions (V ˜ 1 eV) and a hopping pattern with sulfur mediated diagonal next nearest neighbor Bi-S-Bi hopping t’ ˜ 0.88 eV, as well as larger than nearest neighbor Bi-Bi hopping, t ˜ 0.16 eV. Wigner crystals of Cooper pairs quantum melt for doping around x = 0.5 and stabilize certain resonating valence bond states and superconductivity. We study a few variational RVB states and suggest that BiS2 family members are latent high Tc superconductors, but challenged by competing orders and the fragile nature of many body states sustained by unscreened Coulomb forces. One of our superconducting states has d XY symmetry and a gap. We also predict a 2d Bose metal or vortex liquid normal state, as charged -2e valence bonds survive in the normal state.

  16. Global Asymmetries in the Heliosphere: Signature of the Interstellar Magnetic Field

    NASA Astrophysics Data System (ADS)

    Opher, Merav; Alouani-Bibi, Fathallah; Izmodenov, Vladislav; Richardson, John; Toth, Gabor; Gombosi, Tamas

    In recent years it become clear that magnetic field effects, plays an important role in the Heliosphere, from shaping it and possible being responsible for the asymmetries observed in the Voyager data (e.g., Opher et al. 2007, 2009). However, the strength and orientation of the field in the local interstellar medium near the heliosphere has been poorly constrained. Previous estimates of the field strength range from 1.8-2.5 G and the field was thought to be parallel to the Galactic plane or inclined by 38-60 (Lallement et al. 2005) or 60-90 (Opher et al. 2007) to this plane. These estimates relied either on indirect observational inferences or modeling in which the interstellar neutral hydrogen was not taken into account. We will discuss recent work that indicate that based on asymmetries detected by Voyager 1 and 2 and measurements of the deflection of the solar wind plasma flows in the heliosheath (Opher et al. 2009) indicate that the field strength in the local interstellar medium is strong, between 4-5 G (Other works such as Izmodenov 2009; Pogorelov et al. 2009; Ratkiewickz et al. 2009 found similar strength). The field is tilted 20-30 from the interstellar medium flow direction (resulting from the peculiar motion of the Sun in the Galaxy) and is at an angle of about 30 from the Galactic plane. We will discuss the effect of such magnetic field in the global asymmetries of the heliosphere. We further will comment on the effect on asymmetries of our recent model of Kinetic-MHD model treating the neutrals in kinetic fashion (Alouani-Bibi et al. 2010). We will relate our findings with the most recent results of IBEX that indicate that the interstellar magnetic field has a strong signature in the emission of energetic neutrals.

  17. Molecular Characterization of Membrane-Associated Soluble Serine Palmitoyltransferases from Sphingobacterium multivorum and Bdellovibrio stolpii▿

    PubMed Central

    Ikushiro, Hiroko; Islam, Mohammad Mainul; Tojo, Hiromasa; Hayashi, Hideyuki

    2007-01-01

    Serine palmitoyltransferase (SPT) is a key enzyme in sphingolipid biosynthesis and catalyzes the decarboxylative condensation of l-serine and palmitoyl coenzyme A (CoA) to form 3-ketodihydrosphingosine (KDS). Eukaryotic SPTs comprise tightly membrane-associated heterodimers belonging to the pyridoxal 5′-phosphate (PLP)-dependent α-oxamine synthase family. Sphingomonas paucimobilis, a sphingolipid-containing bacterium, contains an abundant water-soluble homodimeric SPT of the same family (H. Ikushiro et al., J. Biol. Chem. 276:18249-18256, 2001). This enzyme is suitable for the detailed mechanistic studies of SPT, although single crystals appropriate for high-resolution crystallography have not yet been obtained. We have now isolated three novel SPT genes from Sphingobacterium multivorum, Sphingobacterium spiritivorum, and Bdellovibrio stolpii, respectively. Each gene product exhibits an ∼30% sequence identity to both eukaryotic subunits, and the putative catalytic amino acid residues are conserved. All bacterial SPTs were successfully overproduced in Escherichia coli and purified as water-soluble active homodimers. The spectroscopic properties of the purified SPTs are characteristic of PLP-dependent enzymes. The KDS formation by the bacterial SPTs was confirmed by high-performance liquid chromatography/mass spectrometry. The Sphingobacterium SPTs obeyed normal steady-state ordered Bi-Bi kinetics, while the Bdellovibrio SPT underwent a remarkable substrate inhibition at palmitoyl CoA concentrations higher than 100 μM, as does the eukaryotic enzyme. Immunoelectron microscopy showed that unlike the cytosolic Sphingomonas SPT, S. multivorum and Bdellovibrio SPTs were bound to the inner membrane of cells as peripheral membrane proteins, indicating that these enzymes can be a prokaryotic model mimicking the membrane-associated eukaryotic SPT. PMID:17557831

  18. Catalytic mechanism and substrate specificity of the beta-subunit of the voltage-gated potassium channel.

    PubMed

    Tipparaju, Srinivas M; Barski, Oleg A; Srivastava, Sanjay; Bhatnagar, Aruni

    2008-08-26

    The beta-subunits of voltage-gated potassium (Kv) channels are members of the aldo-keto reductase (AKR) superfamily. These proteins regulate inactivation and membrane localization of Kv1 and Kv4 channels. The Kvbeta proteins bind to pyridine nucleotides with high affinity; however, their catalytic properties remain unclear. Here we report that recombinant rat Kvbeta2 catalyzes the reduction of a wide range of aldehydes and ketones. The rate of catalysis was slower (0.06-0.2 min(-1)) than those of most other AKRs but displayed the expected hyperbolic dependence on substrate concentration, with no evidence of allosteric cooperativity. Catalysis was prevented by site-directed substitution of Tyr-90 with phenylalanine, indicating that the acid-base catalytic residue, identified in other AKRs, has a conserved function in Kvbeta2. The protein catalyzed the reduction of a broad range of carbonyls, including aromatic carbonyls, electrophilic aldehydes and prostaglandins, phospholipids, and sugar aldehydes. Little or no activity was detected with carbonyl steroids. Initial velocity profiles were consistent with an ordered bi-bi rapid equilibrium mechanism in which NADPH binding precedes carbonyl binding. Significant primary kinetic isotope effects (2.0-3.1) were observed under single- and multiple-turnover conditions, indicating that the bond-breaking chemical step is rate-limiting. Structure-activity relationships with a series of para-substituted benzaldehydes indicated that the electronic interactions predominate during substrate binding and that no significant charge develops during the transition state. These data strengthen the view that Kvbeta proteins are catalytically active AKRs that impart redox sensitivity to Kv channels.

  19. Remaining challenges in cellular flavin cofactor homeostasis and flavoprotein biogenesis

    PubMed Central

    Giancaspero, Teresa A.; Colella, Matilde; Brizio, Carmen; Difonzo, Graziana; Fiorino, Giuseppina M.; Leone, Piero; Brandsch, Roderich; Bonomi, Francesco; Iametti, Stefania; Barile, Maria

    2015-01-01

    The primary role of the water-soluble vitamin B2 (riboflavin) in cell biology is connected with its conversion into FMN and FAD, the cofactors of a large number of dehydrogenases, oxidases and reductases involved in a broad spectrum of biological activities, among which energetic metabolism and chromatin remodeling. Subcellular localisation of FAD synthase (EC 2.7.7.2, FADS), the second enzyme in the FAD forming pathway, is addressed here in HepG2 cells by confocal microscopy, in the frame of its relationships with kinetics of FAD synthesis and delivery to client apo-flavoproteins. FAD synthesis catalyzed by recombinant isoform 2 of FADS occurs via an ordered bi-bi mechanism in which ATP binds prior to FMN, and pyrophosphate is released before FAD. Spectrophotometric continuous assays of the reconstitution rate of apo-D-aminoacid oxidase with its cofactor, allowed us to propose that besides its FAD synthesizing activity, hFADS is able to operate as a FAD “chaperone.” The physical interaction between FAD forming enzyme and its clients was further confirmed by dot blot and immunoprecipitation experiments carried out testing as a client either a nuclear lysine-specific demethylase 1 (LSD1) or a mitochondrial dimethylglycine dehydrogenase (Me2GlyDH, EC 1.5.8.4). Both enzymes carry out similar reactions of oxidative demethylation, in which tetrahydrofolate is converted into 5,10-methylene-tetrahydrofolate. A direct transfer of the cofactor from hFADS2 to apo-dimethyl glycine dehydrogenase was also demonstrated. Thus, FAD synthesis and delivery to these enzymes are crucial processes for bioenergetics and nutri-epigenetics of liver cells. PMID:25954742

  20. Protein kinase activities in ripening mango, Mangifera indica L., fruit tissue. I: Purification and characterization of a calcium-stimulated casein kinase-I.

    PubMed

    Frylinck, L; Dubery, I A

    1998-01-15

    A Ca(2+)-stimulated protein kinase (PK-I), active with dephosphorylated casein as exogenous substrate, was purified from ripening mango fruit. The purification procedure involved 30-70% ammonium sulphate fractionation and sequential anion exchange-, affinity-, hydrophobic interaction- and gel filtration chromatography. PK-I was purified ca. 40-fold with an overall yield of < 1%. The final specific activity in the presence of 0.1 mM Ca2+ was 55 nmol min-1 mg-1. Analysis of the most highly purified preparations revealed a monomeric enzyme with an M(r) of 30.9 kDa and pI of 5.1. PK-I efficiently phosphorylated casein and phosvitin, but did not phosphorylate histone II-S, histone III-S, protamine sulphate or bovine serum albumin. PK-I activity was stimulated by micromolar concentrations of Ca2+ and was dependent on millimolar Mg2+ concentrations, which could not be substituted with Mn2+. PK-I activity was stimulated by, but was not dependent on Ca2+. Calmodulin and calmodulin inhibitors did not affect PK-I activity, but heparin and cAMP acted as inhibitors. The pH and temperature optima of the enzyme under standard reaction conditions were 6.5 and 35 degrees C, respectively. The kinetic reaction mechanism of PK-I was studied by using casein as substrate. Initial velocity and product inhibition studies with ADP as product inhibitor best fit an ordered bi-bi kinetic mechanism with the Mg(2+)-ATP complex binding first to the enzyme followed by binding of the protein substrate. The K(m)ATP and K(m)casein of PK-I were 9 microM and 0.26 mg ml-1, respectively. The KiADP of PK-I was 9 microM.

  1. Remaining challenges in cellular flavin cofactor homeostasis and flavoprotein biogenesis.

    PubMed

    Giancaspero, Teresa A; Colella, Matilde; Brizio, Carmen; Difonzo, Graziana; Fiorino, Giuseppina M; Leone, Piero; Brandsch, Roderich; Bonomi, Francesco; Iametti, Stefania; Barile, Maria

    2015-01-01

    The primary role of the water-soluble vitamin B2 (riboflavin) in cell biology is connected with its conversion into FMN and FAD, the cofactors of a large number of dehydrogenases, oxidases and reductases involved in a broad spectrum of biological activities, among which energetic metabolism and chromatin remodeling. Subcellular localisation of FAD synthase (EC 2.7.7.2, FADS), the second enzyme in the FAD forming pathway, is addressed here in HepG2 cells by confocal microscopy, in the frame of its relationships with kinetics of FAD synthesis and delivery to client apo-flavoproteins. FAD synthesis catalyzed by recombinant isoform 2 of FADS occurs via an ordered bi-bi mechanism in which ATP binds prior to FMN, and pyrophosphate is released before FAD. Spectrophotometric continuous assays of the reconstitution rate of apo-D-aminoacid oxidase with its cofactor, allowed us to propose that besides its FAD synthesizing activity, hFADS is able to operate as a FAD "chaperone." The physical interaction between FAD forming enzyme and its clients was further confirmed by dot blot and immunoprecipitation experiments carried out testing as a client either a nuclear lysine-specific demethylase 1 (LSD1) or a mitochondrial dimethylglycine dehydrogenase (Me2GlyDH, EC 1.5.8.4). Both enzymes carry out similar reactions of oxidative demethylation, in which tetrahydrofolate is converted into 5,10-methylene-tetrahydrofolate. A direct transfer of the cofactor from hFADS2 to apo-dimethyl glycine dehydrogenase was also demonstrated. Thus, FAD synthesis and delivery to these enzymes are crucial processes for bioenergetics and nutri-epigenetics of liver cells.

  2. Bacteriophage T4 Dam DNA-(N6-adenine)-methyltransferase. Processivity and orientation to the methylation target.

    PubMed

    Zinoviev, Victor V; Evdokimov, Alexey A; Malygin, Ernst G; Schlagman, Samuel L; Hattman, Stanley

    2003-03-07

    We carried out steady state and pre-steady state (burst) kinetic analyses of the bacteriophage T4 Dam DNA-(N(6)-adenine)-methyltransferase (MTase)-mediated methyl group transfer from S-adenosyl-l-methionine (AdoMet) to Ade in oligonucleotide duplexes containing one or two specific GATC sites with different combinations of methylated and unmodified targets. We compared the results for ligated 40-mer duplexes with those of the mixtures of the two unligated duplexes used to generate the 40-mers. The salient results are as follows: (i) T4 Dam MTase modifies 40-mer duplexes in a processive fashion. (ii) During processive movement, T4 Dam rapidly exchanges product S-adenosyl-l-homocysteine (AdoHcy) for substrate AdoMet without dissociating from the DNA duplex. (iii) T4 Dam processivity is consistent with an ordered bi-bi mechanism AdoMet downward arrow DNA downward arrow DNA(Me) upward arrow AdoHcy upward arrow. However, in contrast to the steady state, here DNA(Me) upward arrow signifies departure from a methylated site GMTC upward arrow without physically dissociating from the DNA. (iv) Following methyl transfer at one site and linear diffusion to a hemimethylated site, a reconstituted T4 Dam-AdoMet complex rapidly reorients itself to the (productive) unmethylated strand. T4 Dam-AdoHcy cannot reorient at an enzymatically created GMTC site. (v) The inhibition potential of fully methylated sites 5'-GMTC/5'-GMTC is much lower for a long DNA molecule compared with short single-site duplexes.

  3. DNA (cytosine-N4-)- and -(adenine-N6-)-methyltransferases have different kinetic mechanisms but the same reaction route. A comparison of M.BamHI and T4 Dam.

    PubMed

    Malygin, Ernst G; Zinoviev, Victor V; Evdokimov, Alexey A; Lindstrom, William M; Reich, Norbert O; Hattman, Stanley

    2003-05-02

    We studied the kinetics of methyl group transfer by the BamHI DNA-(cytosine-N(4)-)-methyltransferase (MTase) from Bacillus amyloliquefaciens to a 20-mer oligodeoxynucleotide duplex containing the palindromic recognition site GGATCC. Under steady state conditions the BamHI MTase displayed a simple kinetic behavior toward the 20-mer duplex. There was no apparent substrate inhibition at concentrations much higher than the K(m) for either DNA (100-fold higher) or S-adenosyl-l-methionine (AdoMet) (20-fold higher); this indicates that dead-end complexes did not form in the course of the methylation reaction. The DNA methylation rate was analyzed as a function of both substrate and product concentrations. It was found to exhibit product inhibition patterns consistent with a steady state random bi-bi mechanism in which the dominant order of substrate binding and product release (methylated DNA, DNA(Me), and S-adenosyl-l-homocysteine, AdoHcy) was Ado-Met DNA DNA(Me) AdoHcy. The M.BamHI kinetic scheme was compared with that for the T4 Dam (adenine-N(6)-)-MTase. The two differed with respect to an effector action of substrates and in the rate-limiting step of the reaction (product inhibition patterns are the same for the both MTases). From this we conclude that the common chemical step in the methylation reaction, methyl transfer from AdoMet to a free exocyclic amino group, is not sufficient to dictate a common kinetic scheme even though both MTases follow the same reaction route.

  4. Phospholipids chiral at phosphorus. Steric course of the reactions catalyzed by phosphatidylserine synthase from Escherichia coli and yeast

    SciTech Connect

    Raetz, C.R.H.; Carman, G.M.; Dowhan, W.; Jiang, R.T.; Waszkuc, W.; Loffredo, W.; Tsai, M.D.

    1987-06-30

    The steric courses of the reactions catalyzed by phosphatidylserine (PS) synthase from Escherichia coli and yeast were elucidated by the following procedure. R/sub P/ and S/sub P/ isomers of 1,2-dipalmitoyl-sn-glycero-3-(/sup 17/O, /sup 18/O)phosphoethanolamine ((/sup 17/O, /sup 18/O)DPPE) were synthesized and converted to (R/sub P/)- and (S/sub P/)-1,2-dipalmitoyl-sn-glycero-3-(/sup 16/O, /sup 17/O, /sup 18/O)DPPA), respectively, by incubating with phospholipase D. Condensation of (/sup 16/O, /sup 17/O, /sup 18/O)DPPA with cytidine 5'-monophosphomorpholidate in pyridine gave the desired substrate for PS synthase, (/sup 17/O, /sup 18/O)cytidine 5'-diphospho-1,2-dipalmitoyl-sn-glycerol ((/sup 17/O,/sup 18/O)CDP-DPG), as a mixture of several isotopic and configurational isomers. Incubation of (/sup 17/O, /sup 18/O)CDP-DPG), as a mixture of several isotopic and configurational isomers. Incubation of (/sup 17/O, /sup 18/O) CDP-DPG with a mixture of L-serine, PS synthase and PS decarboxylase gave (/sup 17/O, /sup 18/O)DPPE. The configuration and isotopic enrichments of the starting (/sup 17/O, /sup 18/O)DPPE and the product were analyzed by /sup 31/P NMR following trimethylsilylation of the DPPE. The results indicate that the reaction of E. coli PS synthase proceeds with retention of configuration at phosphorus, which suggests a two-step mechanism involving a phosphatidyl-enzyme intermediate, while the yeast PS synthase catalyzes the reaction with inversion of configuration, which suggests a single-displacement mechanism. Such results lend strong support to the ping-pong mechanism proposed for the E. coli enzyme and the sequential Bi-Bi mechanism proposed for the yeast enzyme, both based on previous isotopic exchange experiments.

  5. Analysis of the Escherichia coli glucosamine-6-phosphate synthase activity by isothermal titration calorimetry and differential scanning calorimetry.

    PubMed

    Valerio-Lepiniec, Marie; Aumont-Nicaise, Magali; Roux, Céline; Raynal, Bertrand; England, Patrick; Badet, Bernard; Badet-Denisot, Marie-Ange; Desmadril, Michel

    2010-06-15

    Glucosamine-6-phosphate synthase (GlmS) is responsible for the first and rate-limiting step in the hexosamine biosynthetic pathway. It catalyzes the conversion of D-fructose-6P (F6P) into D-glucosamine-6P (GlcN6P) using L-glutamine (Gln) as nitrogen donor (synthase activity) according to an ordered bi-bi process where F6P binds first. In the absence of F6P, the enzyme exhibits a weak hydrolyzing activity of Gln into Glu and ammonia (glutaminase activity), whereas the presence of F6P strongly stimulates it (hemi-synthase activity). Until now, these different activities were indirectly measured using either coupled enzyme or colorimetric methods. In this work, we have developed a direct assay monitoring the heat released by the reaction. Isothermal titration calorimetry and differential scanning calorimetry were used to determine kinetic and thermodynamic parameters of GlmS. The direct determination at 37 degrees C of kinetic parameters and affinity constants for both F6P and Gln demonstrated that part of the ammonia produced by Gln hydrolysis in the presence of both substrates is not used for the formation of the GlcN6P. The full characterization of this phenomenon allowed to identify experimental conditions where this leak of ammonia is negligible. Enthalpy measurements at 25 degrees C in buffers of various heats of protonation demonstrated that no proton exchange with the medium occurred during the enzyme-catalyzed glutaminase or synthase reaction suggesting for the first time that both products are released as a globally neutral pair composed by the Glu carboxylic side chain and the GlcN6P amine function. Finally we showed that the oligomerization state of GlmS is concentration-dependent. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  6. Recombinant Escherichia coli GMP reductase: kinetic, catalytic and chemical mechanisms, and thermodynamics of enzyme-ligand binary complex formation.

    PubMed

    Martinelli, Leonardo Krás Borges; Ducati, Rodrigo Gay; Rosado, Leonardo Astolfi; Breda, Ardala; Selbach, Bruna Pelegrim; Santos, Diógenes Santiago; Basso, Luiz Augusto

    2011-04-01

    Guanosine monophosphate (GMP) reductase catalyzes the reductive deamination of GMP to inosine monophosphate (IMP). GMP reductase plays an important role in the conversion of nucleoside and nucleotide derivatives of guanine to adenine nucleotides. In addition, as a member of the purine salvage pathway, it also participates in the reutilization of free intracellular bases. Here we present cloning, expression and purification of Escherichia coli guaC-encoded GMP reductase to determine its kinetic mechanism, as well as chemical and thermodynamic features of this reaction. Initial velocity studies and isothermal titration calorimetry demonstrated that GMP reductase follows an ordered bi-bi kinetic mechanism, in which GMP binds first to the enzyme followed by NADPH binding, and NADP(+) dissociates first followed by IMP release. The isothermal titration calorimetry also showed that GMP and IMP binding are thermodynamically favorable processes. The pH-rate profiles showed groups with apparent pK values of 6.6 and 9.6 involved in catalysis, and pK values of 7.1 and 8.6 important to GMP binding, and a pK value of 6.2 important for NADPH binding. Primary deuterium kinetic isotope effects demonstrated that hydride transfer contributes to the rate-limiting step, whereas solvent kinetic isotope effects arise from a single protonic site that plays a modest role in catalysis. Multiple isotope effects suggest that protonation and hydride transfer steps take place in the same transition state, lending support to a concerted mechanism. Pre-steady-state kinetic data suggest that product release does not contribute to the rate-limiting step of the reaction catalyzed by E. coli GMP reductase.

  7. Ecosystem responses to extreme natural events: impacts of three sequential hurricanes in fall 1999 on sediment quality and condition of benthic fauna in the Neuse River Estuary, North Carolina.

    PubMed

    Balthis, W Leonard; Hyland, Jeffrey L; Bearden, Daniel W

    2006-08-01

    A study was conducted in November 1999 to assess sediment quality and condition of benthic fauna in the Neuse River Estuary (NRE), North Carolina, USA, following the passage of three Atlantic hurricanes during the two months prior. Samples for analysis of macroinfauna (>0.5 mm sieve size), chemical contamination of sediments, and other abiotic environmental variables (salinity, dissolved oxygen, pH, depth, sediment granulometry) were collected at 20 sites from the mouth of the Neuse River at Pamlico Sound to approximately 90 km upstream. Results were compared to those obtained from the same area in July 1998 using similar protocols. Depressed salinity, caused by extreme rainfall and associated high freshwater flow, persisted throughout much of the estuary, which had experienced periods of water-column stratification and hypoxia of underlying waters. Fifteen of the 20 sites, representing 299 km2 (76% of the survey area), also showed signs of benthic stress based on a multi-metric benthic index of biotic integrity (B-IBI). Benthic impacts included reductions in the abundance, diversity, and numbers of species and shifts in taxonomic composition, with a notable increase in dominance of the opportunistic polychaete Mediomastus ambiseta as other former dominant species declined. There was no significant increase in the extent of chemical contamination compared to pre-hurricane conditions. Storm-related reductions in dissolved oxygen and salinity were the more likely causes of the observed benthic impacts, though it was not possible, based on these results, to separate storm effects from seasonal changes in the benthos and annual episodes of summer anoxia and hypoxia.

  8. Development and evaluation of a spatially-explicit index of Chesapeake Bay health.

    PubMed

    Williams, Michael; Longstaff, Ben; Buchanan, Claire; Llansó, Roberto; Dennison, William

    2009-01-01

    In an effort to better portray changing health conditions in Chesapeake Bay and support restoration efforts, a Bay Health Index (BHI) was developed to assess the ecological effects of nutrient and sediment loading on 15 regions of the estuary. Three water quality and three biological measures were combined to formulate the BHI. Water quality measures of chlorophyll-a, dissolved oxygen, and Secchi depth were averaged to create the Water Quality Index (WQI), and biological measures of the phytoplankton and benthic indices of biotic integrity (P-IBI and B-IBI, respectively) and the area of submerged aquatic vegetation (SAV) were averaged to create the Biotic Index (BI). The WQI and BI were subsequently averaged to give a BHI value representing ecological conditions over the growing season (i.e., March-October). Lower chlorophyll-a concentrations, higher dissolved oxygen concentrations, deeper Secchi depths, higher phytoplankton and benthic indices relative to ecological health-based thresholds, and more extensive SAV area relative to restoration goal areas, characterized the least-impaired regions. The WQI, P-IBI and BHI were significantly correlated with (1) regional river flow (r=-0.64, -0.57 and -0.49, respectively; p<0.01), (2) nitrogen (N), phosphorus (P) and sediment loads (all positively correlated with flow), and (3) the sum of developed and agricultural land use (highest annual r(2)=0.86, 0.71 and 0.68, respectively) in most reporting regions, indicating that the BHI is strongly regulated by nutrient and sediment loads from these land uses. The BHI uses ecological health-based thresholds that give an accurate representation of the health conditions in Chesapeake Bay and was the basis for an annual, publicly released environmental report card that debuted in 2007.

  9. The Structural and Functional Basis of Catalysis Mediated by NAD(P)H:acceptor Oxidoreductase (FerB) of Paracoccus denitrificans

    PubMed Central

    Sedláček, Vojtěch; Klumpler, Tomáš; Marek, Jaromír; Kučera, Igor

    2014-01-01

    FerB from Paracoccus denitrificans is a soluble cytoplasmic flavoprotein that accepts redox equivalents from NADH or NADPH and transfers them to various acceptors such as quinones, ferric complexes and chromate. The crystal structure and small-angle X-ray scattering measurements in solution reported here reveal a head-to-tail dimer with two flavin mononucleotide groups bound at the opposite sides of the subunit interface. The dimers tend to self-associate to a tetrameric form at higher protein concentrations. Amino acid residues important for the binding of FMN and NADH and for the catalytic activity are identified and verified by site-directed mutagenesis. In particular, we show that Glu77 anchors a conserved water molecule in close proximity to the O2 of FMN, with the probable role of facilitating flavin reduction. Hydride transfer is shown to occur from the 4-pro-S position of NADH to the solvent-accessible si side of the flavin ring. When using deuterated NADH, this process exhibits a kinetic isotope effect of about 6 just as does the NADH-dependent quinone reductase activity of FerB; the first, reductive half-reaction of flavin cofactor is thus rate-limiting. Replacing the bulky Arg95 in the vicinity of the active site with alanine substantially enhances the activity towards external flavins that obeys the standard bi-bi ping-pong reaction mechanism. The new evidence for a cryptic flavin reductase activity of FerB justifies the previous inclusion of this enzyme in the protein family of NADPH-dependent FMN reductases. PMID:24817153

  10. Kinetic analysis using low-molecular mass xyloglucan oligosaccharides defines the catalytic mechanism of a Populus xyloglucan endotransglycosylase

    PubMed Central

    Saura-Valls, Marc; Fauré, Régis; Ragàs, Sergi; Piens, Kathleen; Brumer, Harry; Teeri, Tuula T.; Cottaz, Sylvain; Driguez, Hugues; Planas, Antoni

    2005-01-01

    Plant XETs [XG (xyloglucan) endotransglycosylases] catalyse the transglycosylation from a XG donor to a XG or low-molecular-mass XG fragment as the acceptor, and are thought to be important enzymes in the formation and remodelling of the cellulose-XG three-dimensional network in the primary plant cell wall. Current methods to assay XET activity use the XG polysaccharide as the donor substrate, and present limitations for kinetic and mechanistic studies of XET action due to the polymeric and polydisperse nature of the substrate. A novel activity assay based on HPCE (high performance capillary electrophoresis), in conjunction with a defined low-molecular-mass XGO {XG oligosaccharide; (XXXGXXXG, where G=Glcβ1,4- and X=[Xylα1,6]Glcβ1,4-)} as the glycosyl donor and a heptasaccharide derivatized with ANTS [8-aminonaphthalene-1,3,6-trisulphonic acid; (XXXG-ANTS)] as the acceptor substrate was developed and validated. The recombinant enzyme PttXET16A from Populus tremula x tremuloides (hybrid aspen) was characterized using the donor/acceptor pair indicated above, for which preparative scale syntheses have been optimized. The low-molecular-mass donor underwent a single transglycosylation reaction to the acceptor substrate under initial-rate conditions, with a pH optimum at 5.0 and maximal activity between 30 and 40 °C. Kinetic data are best explained by a ping-pong bi-bi mechanism with substrate inhibition by both donor and acceptor. This is the first assay for XETs using a donor substrate other than polymeric XG, enabling quantitative kinetic analysis of different XGO donors for specificity, and subsite mapping studies of XET enzymes. PMID:16356166

  11. Expression, purification and characterization of enoyl-ACP reductase II, FabK, from Porphyromonas gingivalis

    SciTech Connect

    Hevener, Kirk E.; Mehboob, Shahila; Boci, Teuta; Truong, Kent; Santarsiero, Bernard D.; Johnson, Michael E.

    2012-10-25

    The rapid rise in bacterial drug resistance coupled with the low number of novel antimicrobial compounds in the discovery pipeline has led to a critical situation requiring the expedient discovery and characterization of new antimicrobial drug targets. Enzymes in the bacterial fatty acid synthesis pathway, FAS-II, are distinct from their mammalian counterparts, FAS-I, in terms of both structure and mechanism. As such, they represent attractive targets for the design of novel antimicrobial compounds. Enoyl-acyl carrier protein reductase II, FabK, is a key, rate-limiting enzyme in the FAS-II pathway for several bacterial pathogens. The organism, Porphyromonas gingivalis, is a causative agent of chronic periodontitis that affects up to 25% of the US population and incurs a high national burden in terms of cost of treatment. P. gingivalis expresses FabK as the sole enoyl reductase enzyme in its FAS-II cycle, which makes this a particularly appealing target with potential for selective antimicrobial therapy. Herein we report the molecular cloning, expression, purification and characterization of the FabK enzyme from P. gingivalis, only the second organism from which this enzyme has been isolated. Characterization studies have shown that the enzyme is a flavoprotein, the reaction dependent upon FMN and NADPH and proceeding via a Ping-Pong Bi-Bi mechanism to reduce the enoyl substrate. A sensitive assay measuring the fluorescence decrease of NADPH as it is converted to NADP{sup +} during the reaction has been optimized for high-throughput screening. Finally, protein crystallization conditions have been identified which led to protein crystals that diffract x-rays to high resolution.

  12. Trans-sialidase activity of Photobacterium damsela α2,6-sialyltransferase and its application in the synthesis of sialosides

    PubMed Central

    Cheng, Jiansong; Huang, Shengshu; Yu, Hai; Li, Yanhong; Lau, Kam; Chen, Xi

    2010-01-01

    Trans-sialidases catalyze the transfer of a sialic acid from one sialoside to an acceptor to form a new sialoside. α2,3-Trans-sialidase activity was initially discovered in the parasitic protozoan Trypanosoma cruzi, and more recently was found in a multifunctional Pasteurella multocida sialyltransferase PmST1. α2,8-Trans-sialidase activity was also described for a multifunctional Campylobacter jejuni sialyltransferase CstII. We report here the discovery of the α2,6-trans-sialidase activity of a previously reported recombinant truncated bacterial α2,6-sialyltransferase from Photobacterium damsela (Δ15Pd2,6ST). This is the first time that the α2,6-trans-sialidase activity has ever been identified. Kinetic studies indicate that Δ15Pd2,6ST-catalyzed trans-sialidase reaction follows a ping-pong bi-bi reaction mechanism. Cytidine 5′-monophosphate, the product of sialyltransferase reactions, is not required by the trans-sialidase activity of the enzyme but enhances the trans-sialidase activity modestly as a non-essential activator. Using chemically synthesized Neu5AcαpNP and LacβMU, α2,6-linked sialoside Neu5Acα2,6LacβMU has been obtained in one-step in high yield using the trans-sialidase activity of Δ15Pd2,6ST. In addition to the α2,6-trans-sialidase activity, Δ15Pd2,6ST also has α2,6-sialidase activity. The multifunctionality is thus a common feature of many bacterial sialyltransferases. PMID:19880425

  13. A New Synthetic Route to N-Benzyl Carboxamides through the Reverse Reaction of N-Substituted Formamide Deformylase

    PubMed Central

    Hashimoto, Yoshiteru; Sakashita, Toshihide; Fukatsu, Hiroshi; Sato, Hiroyoshi

    2014-01-01

    Previously, we isolated a new enzyme, N-substituted formamide deformylase, that catalyzes the hydrolysis of N-substituted formamide to the corresponding amine and formate (H. Fukatsu, Y. Hashimoto, M. Goda, H. Higashibata, and M. Kobayashi, Proc. Natl. Acad. Sci. U. S. A. 101:13726–13731, 2004, doi:10.1073/pnas.0405082101). Here, we discovered that this enzyme catalyzed the reverse reaction, synthesizing N-benzylformamide (NBFA) from benzylamine and formate. The reverse reaction proceeded only in the presence of high substrate concentrations. The effects of pH and inhibitors on the reverse reaction were almost the same as those on the forward reaction, suggesting that the forward and reverse reactions are both catalyzed at the same catalytic site. Bisubstrate kinetic analysis using formate and benzylamine and dead-end inhibition studies using a benzylamine analogue, aniline, revealed that the reverse reaction of this enzyme proceeds via an ordered two-substrate, two-product (bi-bi) mechanism in which formate binds first to the enzyme active site, followed by benzylamine binding and the subsequent release of NBFA. To our knowledge, this is the first report of the reverse reaction of an amine-forming deformylase. Surprisingly, analysis of the substrate specificity for acids demonstrated that not only formate, but also acetate and propionate (namely, acids with numbers of carbon atoms ranging from C1 to C3), were active as acid substrates for the reverse reaction. Through this reaction, N-substituted carboxamides, such as NBFA, N-benzylacetamide, and N-benzylpropionamide, were synthesized from benzylamine and the corresponding acid substrates. PMID:24123742

  14. Kilometer-scale, late Miocene and early Pliocene surface uplift in East Greenland: tectonic forerunners for the build-up of the Greenland Ice Sheet

    NASA Astrophysics Data System (ADS)

    Japsen, Peter; Green, Paul F.; Bonow, Johan M.

    2015-04-01

    anchoring points during the build-up of the Greenland Ice Sheet over the period leading up to the Pleistocene (Solgaard et al., 2013). Tectonic processes thus underpinned the build-up of the Greenland Ice Sheet (Steinberger et al., 2015). The three uplift phases in Greenland overlap in time with similar events in North America and Europe and correlate with changes in plate motion. The much higher elevation of East Greenland compared to West Greenland suggests active support in the east from the Iceland plume. These observations indicate a connection between mantle convection, changes in plate motion and vertical movements along passive continental margins. Bonow, J.M. et al. 2014. Global Planet. Change 116, 10-29. Japsen, P. et al. 2014. Global Planet. Change 116, 91-114. Molnar, P., England, P.C. 1990. Nature 346, 29-34. Solgaard, A.M. et al. 2013. Palaeogeography Palaeoclimatology Palaeoecology 392, 161-176. Steinberger, B. et al. 2015. Terra Nova in press.

  15. Single haplotype assembly of the human genome from a hydatidiform mole.

    PubMed

    Steinberg, Karyn Meltz; Schneider, Valerie A; Graves-Lindsay, Tina A; Fulton, Robert S; Agarwala, Richa; Huddleston, John; Shiryev, Sergey A; Morgulis, Aleksandr; Surti, Urvashi; Warren, Wesley C; Church, Deanna M; Eichler, Evan E; Wilson, Richard K

    2014-12-01

    A complete reference assembly is essential for accurately interpreting individual genomes and associating variation with phenotypes. While the current human reference genome sequence is of very high quality, gaps and misassemblies remain due to biological and technical complexities. Large repetitive sequences and complex allelic diversity are the two main drivers of assembly error. Although increasing the length of sequence reads and library fragments can improve assembly, even the longest available reads do not resolve all regions. In order to overcome the issue of allelic diversity, we used genomic DNA from an essentially haploid hydatidiform mole, CHM1. We utilized several resources from this DNA including a set of end-sequenced and indexed BAC clones and 100× Illumina whole-genome shotgun (WGS) sequence coverage. We used the WGS sequence and the GRCh37 reference assembly to create an assembly of the CHM1 genome. We subsequently incorporated 382 finished BAC clone sequences to generate a draft assembly, CHM1_1.1 (NCBI AssemblyDB GCA_000306695.2). Analysis of gene, repetitive element, and segmental duplication content show this assembly to be of excellent quality and contiguity. However, comparison to assembly-independent resources, such as BAC clone end sequences and PacBio long reads, indicate misassembled regions. Most of these regions are enriched for structural variation and segmental duplication, and can be resolved in the future. This publicly available assembly will be integrated into the Genome Reference Consortium curation framework for further improvement, with the ultimate goal being a completely finished gap-free assembly. © 2014 Steinberg et al.; Published by Cold Spring Harbor Laboratory Press.

  16. Spatial and Developmental Effects on the Accumulation of Mercury in Antarctic Krill (E. superba) Along the West Antarctic Peninsula (WAP)

    NASA Astrophysics Data System (ADS)

    Sontag, P.; Steinberg, D. K.; Reinfelder, J. R.

    2016-02-01

    Philip T. Sontag1, Deborah K. Steinberg2, and John R. Reinfelder11Rutgers University, Department of Environmental Sciences, New Brunswick, New Jersey, USA 2College of William and Mary, Virginia Institute of Marine Science, Gloucester Point, Virginia, USAThe Antarctic krill Euphausia superba is a critical component of the WAP food web and is therefore a potentially important link in the transfer of mercury (Hg) to higher trophic levels including penguins, seals, and whales. In order to examine ontogenetic (juvenile, adult), spatial (north-south, onshore-offshore) and annual differences in Hg accumulation by E. superba, we measured concentrations of total Hg (THg) and monomethylmercury (MMHg) in krill collected at northern ( 64.5°S) and southern (67.4-69°S) stations during the summers of 2013-2015 along the WAP. Total mercury in krill (4.6 ± 1.1 to 20 ± 13 ng g-1), which includes both inorganic Hg and organic MMHg (0.3 ± 0.2 to 3.2 ± 0.8 ng g-1) was higher in offshore than nearshore adults in 2014, but north-south differences in krill THg were not observed. THg concentrations were positively correlated with trophic level (derived from δ15N) for both juvenile (R2=0.86) and adult (R2=0.45) krill at northern and southern stations. However, higher concentrations of MMHg, the form of Hg that biomagnifies in marine food webs, were observed in juvenile than adult E. superba collected at the same latitude and longitude (p<0.005). In addition, both juvenile and adult krill collected at northern latitudes contained higher MMHg concentrations than krill collected farther south near the summer sea ice edge (p<0.005). Differences in MMHg accumulation in krill were not explained by δ15N-based trophic levels indicating that spatial and developmental factors were most important.

  17. Responses of coastal ecosystems to environmental variability in emerging countries from the Americas

    NASA Astrophysics Data System (ADS)

    Muniz, Pablo; Calliari, Danilo; Giménez, Luis; Defeo, Omar

    2015-12-01

    Coastal ecosystems supply critical ecological services and benefits to human society (Barbier et al., 2011). Nearly 38% of the global monetary value of annual ecosystem services arises from estuaries, seagrass and algal beds, coral reefs and shelf ecosystems (Costanza et al., 1997). However, these ecosystems are being increasingly affected by multiple drivers acting simultaneously at several spatial and temporal scales (Lotze et al., 2006; Hoegh-Guldberg and Bruno, 2010). Climate change (temperature increase, sea level rise, ocean acidification), human activities (e.g. land use/cover change, pollution, overexploitation, translocation of species), and extreme natural events (storms, floods, droughts) are the most important drivers degrading the resilience of coastal systems. Such factors operate on individual level processes, leading organisms away from their niches (Steinberg, 2013) or modifying rates and phenology (Giménez, 2011; Mackas et al., 2012, Deutsch et al., 2015). All of these influence ecosystem level processes, causing changes in species composition, diversity losses and deterioration of ecosystem functions (Worm et al., 2006; Defeo et al., 2009; Doney et al., 2011; Dornelas et al., 2014). The rate of change in habitats, species distributions and whole ecosystems has accelerated over the past decades as shown, for example, in the increase in the frequency of events of coastal hypoxia (Diaz and Rosenberg, 2008,Vaquer-Sunyer and Duarte, 2008), extensive translocation of species by global shipping (Seebens et al., 2013), and in ecosystem regime shifts (Möllmann et al., 2015 and references therein). Some coastal areas have been transformed into novel ecosystems with physical and biological characteristics outside their natural range of variability (Cloern et al., 2015) while others are likely to become sink areas, limiting the migration of marine species away from warming habitats (Burrows et al., 2014).

  18. Dissociative amnesia in dissociative disorders and borderline personality disorder: self-rating assessment in a college population.

    PubMed

    Sar, Vedat; Alioğlu, Firdevs; Akyuz, Gamze; Karabulut, Sercan

    2014-01-01

    Dissociative amnesia (DA) among subjects with a dissociative disorder and/or borderline personality disorder (BPD) recruited from a nonclinical population was examined. The Steinberg Dissociative Amnesia Questionnaire (SDAQ), the Childhood Trauma Questionnaire, and the self-report screening tool of the BPD section of the Structured Clinical Interview for DSM-IV(SCID-BPD) were administered to 1,301 college students. A total of 80 participants who were diagnosed with BPD according to the clinician-administered SCID-BPD and 111 nonborderline controls were evaluated using the Structured Clinical Interview for DSM-IV Dissociative Disorders (SCID-D) by a psychiatrist blind to diagnosis and scale scores. Internal consistency analyses and test-retest evaluations suggested that the SDAQ is a reliable instrument for the population studied. Of the participants, 20.6% reported an SDAQ score of 20 or above and impairment by DA. Those who had both dissociative disorder and BPD (n = 78) had the highest SDAQ scores. Both disorders had significant effects on the SCID-D total and amnesia scores in the variance analysis. On SDAQ scores, however, only BPD had this effect. There was a significant interaction between the 2 disorders for the SCID-D total but not for the SDAQ or SCID-D amnesia scores. BPD represented the severity of dissociation and childhood trauma in this study group. However, in contrast to the dissociative disorders, BPD was characterized by better awareness of DA in self-report. The discrepancies between self-report and clinical interview associated with BPD and dissociative disorders are discussed in the context of betrayal theory (J. J. Freyd, 1994) of BPD and perceptual theory (D. B. Beere, 2009) of dissociative disorders.

  19. Awareness of identity alteration and diagnostic preference between borderline personality disorder and dissociative disorders.

    PubMed

    Sar, Vedat; Alioğlu, Firdevs; Akyuz, Gamze; Tayakısı, Emre; Öğülmüş, Ezgi F; Sönmez, Doğuş

    2017-01-01

    This study inquires into identity alteration among college students and its relationship to borderline personality disorder (BPD) and/or dissociative disorders (DDs). Steinberg Identity Alteration Questionnaire (SIAQ), Childhood Trauma Questionnaire (CTQ), and self-report screening tool of the BPD section of the Structured Clinical Interview for DSM-IV (SCID-BPD) were administered to 1301 college students. Participants who fit the diagnostic criteria of BPD (n = 80) according to the clinician-administered SCID-BPD and 111 non-BPD controls were evaluated using the Structured Clinical Interview for DSM-IV DDs (SCID-D) by two psychiatrists blind to the group membership and scale scores. Test-retest evaluations and internal consistency analyses suggested that SIAQ was a reliable instrument. Of the participants, 11.3% reported a SIAQ score 25 or above alongside some impairment. SIAQ scores differentiated participants who fit the diagnostic criteria for a DD from those who did not. While self-report identity alteration was correlated with all childhood trauma types, clinician-assessed identity alteration was correlated with childhood sexual abuse only. Those who fit criteria for both disorders had the highest identity alteration scores in self-report and clinician-assessment. Although both syndromes had significant effect on self-report identity alteration total scores, in contrast to DD, BPD did not have an effect on the clinician-administered evaluation. An impression of personality disorder rather than a DD may seem more likely when identity alteration remains subtle in clinical assessment, notwithstanding its presence in self-report. Lack of recognition of identity alteration may lead to overdiagnosis of BPD among individuals who have a DD.

  20. Accessing Ultra-High Pressure, Quasi-Isentropic States of Matter

    SciTech Connect

    Lorenz, K T; Edwards, M J; Glendinning, S G; Ho, D D; Jankowski, A F; McNaney, J; Pollaine, S M; Remington, B A

    2004-11-12

    A new approach to the study of material strength of metals at extreme pressures has been developed on the Omega laser, using a ramped plasma piston drive. The laser drives a shock through a solid plastic reservoir that unloads at the rear free surface, expands across a vacuum gap, and stagnates on the metal sample under study. This produces a gently increasing ram pressure, compressing the sample nearly isentropically. The peak pressure on the sample, inferred from VISAR measurements of velocity, can be varied by adjusting the laser energy and pulse length, gap size, and reservoir density, and obeys a simple scaling relation. In an important application, using in-flight x-ray radiography, the material strength of solid-state samples at high pressure can be inferred by measuring the reductions in the growth rates (stabilization) of Rayleigh-Taylor (RT) unstable interfaces. This paper reports the first attempt to use this new laser-driven, quasi-isentropic technique for determining material strength in high-pressure solids. Modulated foils of Al-6061-T6 were accelerated and compressed to peak pressures of 200 kbar. Modulation growth was recorded at a series of times after peak acceleration and well into the release phase. Fits to the growth data, using a Steinberg-Guinan (SG) constitutive strength model, give yield strengths 30% greater than those given by the nominal parameters for Al-6061-T6. Calculations indicate that the dynamic enhancement to the yield strength at 200 kbar is a factor of {approx}2.5x over the ambient yield strength of 2.9 kbar. Experimental designs based on this drive developed for the NIF laser, predict that solid-state samples can be quasi-isentropically driven to pressures an order of magnitude higher than on Omega--accessing new regimes of dense, high-pressure matter.

  1. Behavior of titanium dioxide nanoparticles in Lemna minor growth test conditions.

    PubMed

    Li, Ling; Sillanpää, Markus; Tuominen, Meri; Lounatmaa, Kari; Schultz, Eija

    2013-02-01

    Titanium dioxide nanoparticles (TiO(2) NPs) have raised concern of environmental risks due to their widespread applications, but little is known about the potential toxicity of TiO(2) NPs to aquatic plants. The aim of this work was to study the effects of TiO(2) NPs on Lemna minor and to study the behavior of TiO(2) NPs under modified ISO 20079 test conditions. TiO(2) NPs had a tendency to aggregate in ISO (Steinberg) growth medium, but modification of the standard growth medium enabled the exposure of L. minor to TiO(2) NPs. By dilution of the growth medium (1:10), and exposure under semi-static conditions with medium renewal every second or third day, the size of TiO(2) particles remained rather stable throughout the test period. TiO(2) NPs showed no adverse effect on the growth rate or chlorophyll a content of L. minor, even at a high exposure concentration of 5 mg L(-1) and extended exposure time of 14 days. TiO(2) NPs attached onto L. minor cell walls, but no cellular uptake was observed. Although TiO(2) NPs were not toxic to L. minor, the potential transfer of TiO(2) NPs in aquatic food chains, e.g. attached to the plant leaves and other biological surfaces may be of importance, causing exposure of other organisms and contributing to the environmental fate of nanoparticles. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Immunoglobulin (GM and KM) allotypes and relation to population history in native peoples of British Columbia: Haida and Bella Coola.

    PubMed

    Field, L L; Gofton, J P; Kinsella, T D

    1988-06-01

    Differences in the frequencies of GM haplotypes among native peoples of the Americas support the hypothesis that there were three distinct waves of migration from northeast Asia into the Americas: Paleo-Indian, Na-Dene, and Inuit (Eskimo)-Aleut (Salzano and Steinberg: Am. J. Hum. Genet. 17:273-279, 1965; Sukernik and Osipova: Hum. Genet. 61:148-153, 1982; Williams et al.:Am. J. Phys. Anthropol. 66:1-19, 1985; Szathmary: In R Kirk and E Szathmary (eds): Out of Asia: Peopling of the Americas and the Pacific. Canberra: The Journal of Pacific History, Canberra Australian National University, pp. 79-104, 1985). We studied GM allotypes in two linguistically unique populations of Canadian west coast native peoples, the Haida and the Bella Coola, and compared them to GM frequencies in populations that are supposed descendants of the three migrations, in order to investigate the possible genetic relationships of these British Columbia (BC) groups to other native populations. We also estimated the amount of European admixture from the frequency of the Caucasian haplotype, Gm3;5. Results showed that the frequencies in both BC populations of the three common native haplotypes (Gm1,17;21, Gm1,2,17;21, and Gm1,17;15,16), were intermediate between the frequencies in supposed descendants of Paleo-Indian and Na-Dene. These genetic findings are consistent with the controversial hypothesis of archeologist C. Borden (Science 203:963-971, 1979) that, following deglaciation about 13,000 years ago, British Columbia was repopulated by peoples from the north (?Na-Dene) and by culturally distinct peoples from the south (?Paleo-Indian). Caucasian admixture estimates suggested that the Haida and Bella Coola have also experienced moderate amounts (12-20%) of genetic input from European-originating peoples.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. [The history of audiology].

    PubMed

    Sente, Marko

    2004-01-01

    The paper presents historical data on development of audiology as a medical speciality. It gives the chronological overview of the most significant discoveries which have contributed to the progress and constant development of the science of hearing. The insights and discoveries encompass the ancient, medieval and contemporary medical science. THE TERM "AUDIOLOGY" AND FIRST ASSOCIATIONS OF AUDIOLOGISTS: The paper reviews the origin of the term "audiology" and the time of its occurrence. The First World Congress of Audiologists was held in 1948, and the Conference of Audiologists and Phoniatrists of Yugoslavia was established in 1974. The ancient scientists and philosophers mentioned in the paper are as follows: Democritus, Hippocrates, Empedocles, Plato, Aristotle, and Galenus. Discoveries of Vesalius, Fallopio, Eustachio, Duverney, Schelhammer, Catugno and Helmholtz marked their epochs and made a great contribution to the development of the entire medical science, including audiology. A significant contribution to audiology was made by Schwartz in 1920 and Fletcher in 1926, constructors of audiometers. Fowler, Weigel and Fletcher promoted an audiogram in 1922. Wever and Bray first introduced the cochlear microphonic potentials. The first modern audiometer with a flat zero line for all pitches was constructed in 1937. In 1947, Bekesy constructed the automatic audiometer, and the theory of mobile waves was introduced in 1928. Fletcher and Steinberg promoted speech audiometries in 1929. Mendel and Goldstein described medium latency responses in 1969. The first hearing aids worn within the ear appeared in the same year. William House pioneered the cochlear implantation in adults in 1969, and the program of infant cochlear implants. Jewett described the evoked auditory potentials in 1970. James Jerger classified tympanometric curves into three tympanogram types (A, B, C). Portmann and Arran introduced transtympanic electrocochleography in 1971. Kemp introduced

  4. Hyperbaric oxygen for stage I and II femoral head osteonecrosis.

    PubMed

    Koren, Lior; Ginesin, Eyal; Melamed, Yehuda; Norman, Doron; Levin, Daniel; Peled, Eli

    2015-03-01

    Hyperbaric oxygen therapy is a suggested joint-preserving treatment for symptomatic early-stage osteonecrosis of the femoral head. Limited studies of this treatment have been published. The goal of this study was to evaluate the effectiveness of this treatment in a relatively large patient cohort. The authors reviewed the files of 68 patients with 78 symptomatic joints with Steinberg stage I and II osteonecrosis of the femoral head. All patients were treated with hyperbaric oxygen at the authors' medical health center. Pretreatment and immediate posttreatment magnetic resonance imaging (MRI) findings were compared. On follow-up, a telephone interview was conducted to determine the survival of the joint. Modified Harris Hip Score and Short Form 12 health survey (SF-12) questionnaires of the start of treatment and at follow-up were obtained and evaluated for statistically significant differences. Half of the joints were stage 1 and half were stage II. Seventy-four joints underwent both pre- and posttreatment MRI. Eighty-eight percent of joints showed improvement posttreatment. On follow-up at a mean of 11.1±5.1 years, 54 patients (58 joints) were located and answered the questionnaires. At the time of follow-up, 93% of the joints survived. Mean Harris Hip Score improved from 21 to 81 (P<.0001), the mean physical component of the SF-12 improved from 24 to 46 (P<.0001), and the mean mental component of the SF-12 improved from 54 to 59 (P<.0001). The authors concluded that hyperbaric oxygen treatment is effective in preserving the hip joint in stage I and II osteonecrosis of the femoral head. Copyright 2015, SLACK Incorporated.

  5. Comparative Study of the December 28, 2015 - January 2, 2016 and April 7 - 11, 1997 Sun-Earth Connection Events

    NASA Astrophysics Data System (ADS)

    Berdichevsky, D. B.; Richardson, I. G.; Farrugia, C. J.

    2016-12-01

    A Sun-Earth connection event started on December 28, 2015 in association with a M1.8 X-ray flare, commencing at 1120 UT detected by the GOES Environmental satellites, and a partial halo coronal mass ejection (CME) observed from 1200 UT by the SOHO LASCO coronographs. SDO AIA observations indicate that this event was located at W11S22. The related interplanetary coronal mass ejection (ICME) drove an above average strength fast-forward interplanetary shock observed by the Wind spacecraft at the start of Dec 31. This shock also appears to have accelerated solar energetic particles; ACE/EPAM observations show that these energetic particles peaked at shock passage. The shock driver, i.e. the ICME, appears to have impacted the Earth's environment near 17 UT on December 31. This ICME seems to have included several substructures and possibly extended to around midday on January 2, 2016. The impact of the ICME produced lively auroras at low Earth latitudes in the Western-North hemisphere. The associated strong magnetic storm was due to the leading part of the ICME maintaining a southward-oriented magnetic field for several hours. The purpose of this study is to compare and contrast this event with the April 7-11, 1997 Sun-Earth connection event previously discussed by Berdichevsky et al. (1998) which included the passage of an ICME at Earth with a persistent northward, rather than southward, magnetic-field and produced an unusually long-lasting compression of the Earth's magnetosphere. Berdichevsky, D, J.-L. Bougeret, J.-P. Delaboudinière, N. Fox, M. Kaiser, R. Lepping, D. Michels, S. Plunkett, D. Reames, M. Reiner, I. Richardson, G. Rostoker, J. Steinberg, B. Thompson, and T. von Rosenvinge, Evidence for multiple ejecta: April 7-11, 1997, ISTP Sun-Earth connection event GRL, 25, 2473-6, 1998.

  6. The Intelligibility of Words, Sentences and Continuous Discourse Using the Articulation Index.

    NASA Astrophysics Data System (ADS)

    Depaolis, Rory Adam

    The purpose of this research was to investigate the effect of message redundancy upon intelligibility. The original methodology for the Articulation Index (AI) (French and Steinberg, J. Acoust. Soc. Am., 19, 90-119, 1947) was used to examine the relation between words, meaningful sentences and continuous discourse (CD). One primary consideration was to derive the relations between the three speech types with tightly controlled, highly repeatable experimental conditions such that any differences between them could be attributed solely to inherent contextual differences. One male speaker recorded 616 monosyllabic words, 176 meaningful speech perception in noise (SPIN) sentences and forty-four 7th grade reading level CD passages. Twenty -four normal hearing subjects made intelligibility estimates of the CD and sentences and identified words at each of 44 conditions of filtering and signal-to-noise ratio. The sentence intelligibility scores and continuous discourse intelligibility scores plotted versus the AI (transfer function) were within 0.05 AI of each other. The word recognition scores were considerably lower for equivalent AI values of both sentences and CD. A plot of the importance of the frequency bands used in this study toward understanding speech revealed that the area of most importance was centered around 2000 Hz for all three types of speech. As message redundancy increased (words to sentences to CD) the shape of this area spread progressively to include lower and higher frequencies. A recalculation of the frequency importance function into bands comparable to octave bands revealed that the sentence and CD functions were nearly identical. This fact coupled with the similarity of the sentence and CD transfer functions implies that the two speech types can be used interchangeably when computing the octave band AI. However, the differences between the frequency importance functions in the smaller bands used in this study demonstrated that the assumption that

  7. A Geodynamic Grand Challenge: Time-Reversed Mantle Convection Reconstructions From Tomographic Images of Present-Day Mantle Structure

    NASA Astrophysics Data System (ADS)

    Glisovic, P.; Forte, A. M.; Moucha, R.

    2009-12-01

    One of the most complex challenges in current geodynamics research is the reconstruction of the past evolution of 3-D mantle temperature structure from seismic tomographic images of present-day lateral heterogeneity in the mantle. Early efforts to address this problem have been based on backward advection approximations based on the assumption that mantle convection is a very-high Rayleigh number process (e.g. Forte & Mitrovica 1997; Steinberger & O'Connell 1997). Over the past decade further progress has been achieved and new techniques have been proposed, such as the 4-D variational (Bunge et al. 2003) and quasi-reversible (Ismail-Zadeh et al. 2007) approaches. An enduring challenge is the construction of time-reversed mantle convection simulations that yield maximum consistency with a wide suite of surface geodynamic constraints on mantle rheology and 3-D structure inferred from seismic tomography. Resolving this outstanding problem is of crucial importance, because a successful reconstruction of the time-dependent, 3-D mantle convective structure in the geological past provides unique insights into the origin and evolution of a number of fundamental surface processes that include topography changes, eustatic sea level variations, state of stress in the lithosphere, and Earth rotation variations. A key concern in these reconstructions is quantifying the inherent uncertainties and the implications for surface geodynamic observables. We will explore these issues and compare the efficacy of different backward convection techniques using a new mantle convection model based on recent joint seismic-geodynamic tomography inversions (Simmons et al., GJI, 2009).

  8. Dynamic Strength of Metals at High Pressure and Strain Rate

    NASA Astrophysics Data System (ADS)

    Lorenz, Thomas

    2006-03-01

    A new approach to materials science at very high pressures and strain rates has been developed on the Omega laser, using a ramped plasma piston drive. A laser drives an ablative shock through a solid plastic reservoir where it unloads at the rear free surface, expands across a vacuum gap, and stagnates on the metal sample under study. This produces a gently increasing ram pressure, compressing the sample nearly isentropically. The peak pressure on the sample, diagnosed with VISAR measurements, can be varied by adjusting the laser energy and pulse length, gap size, and reservoir density, and obeys a simple scaling relation.^1 This has been demonstrated at OMEGA at pressures to 200 GPa in Al foils. In an important application, using in-flight x-ray radiography, the material strength of solid-state samples at high pressure can be inferred by measuring the reductions in the growth rates (stabilization) of Rayleigh-Taylor (RT) unstable interfaces. RT instability measurements of solid of Al-6061-T6 ^2 and vanadium, at pressures of 20-100 GPa, and strain rates of 10^6 to 10^8 s-1, show clear material strength effects. Modelling results for two constitutive strength models -- Steinberg-Guinan and Preston-Tonks-Wallace, show enhanced dynamic strength that may be correlated with a high-strain-rate, phono-drag mechanism. Data, modeling details and future prospects for this project using the National Ignition Facility laser, will be presented. [1] J. Edwards et al., Phys. Rev. Lett., 92, 075002 (2004). [2] K. T. Lorenz et al., Phys. Plasmas 12, 056309 (2005). This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

  9. Binary-YORP Coefficients for Known Asteroid Shapes

    NASA Astrophysics Data System (ADS)

    McMahon, Jay W.; Scheeres, D. J.

    2012-10-01

    The binary YORP (bYORP) effect has been hypothesized to be a significant factor in the evolution of near-Earth binary asteroid systems (Cuk and Burns, Icarus, v.176, pp.418-431, 2005; McMahon and Scheeres, CMDA, v.106, pp.261-300, 2010). However, understanding of the coefficient values for realistic asteroid shapes is lacking due to the small number of shape models available for the generally smaller secondary asteroids. Until now, we have only calculated the coefficients based on the shape of 1999 KW4 Beta, although various studies by other authors have computed coefficients for artificially generated asteroids based on Gaussian Spheres and some shape models without self-shadowing (Steinberg and Sari, The Astronomical Journal, v.141, pp.55-64, 2011). We also scaled the 1999 KW4 Beta coefficients to other binary systems with no knowledge of the other systems' secondary shapes in order to make evolutionary predictions (McMahon and Scheeres, Icarus Vol. 209, pp 494-509, 2010). In this study, we compute the bYORP coefficient for a range of asteroid shapes, using these as a stand-in for actual secondaries. This allows us to circumvent the lack of information on binary asteroid secondaries and to develop a richer database of realistic coefficients. While this approach may miss some key features of binary secondaries, at the least it provides some statistics on the expected variability of the bYORP coefficient. We analyze all available asteroid shape models on the PDS-SBN, including radar-based shape models and models estimated from past spacecraft missions. The coefficients are computed with an updated algorithm that includes the effects of self-shadowing. We also present the coefficients for perturbed versions of the available shape models, which give effective error bars to the computed coefficients due to inexact shape models. Finally, we discuss the dynamical implications of the derived bYORP coefficients on binary asteroid evolution.

  10. Extracellular DNA in Single- and Multiple-Species Unsaturated Biofilms

    PubMed Central

    Steinberger, R. E.; Holden, P. A.

    2005-01-01

    The extracellular polymeric substances (EPS) of bacterial biofilms form a hydrated barrier between cells and their external environment. Better characterization of EPS could be useful in understanding biofilm physiology. The EPS are chemically complex, changing with both bacterial strain and culture conditions. Previously, we reported that Pseudomonas aeruginosa unsaturated biofilm EPS contains large amounts of extracellular DNA (eDNA) (R. E. Steinberger, A. R. Allen, H. G. Hansma, and P. A. Holden, Microb. Ecol. 43:416-423, 2002). Here, we investigated the compositional similarity of eDNA to cellular DNA, the relative quantity of eDNA, and the terminal restriction fragment length polymorphism (TRFLP) community profile of eDNA in multiple-species biofilms. By randomly amplified polymorphic DNA analysis, cellular DNA and eDNA appear identical for P. aeruginosa biofilms. Significantly more eDNA was produced in P. aeruginosa and Pseudomonas putida biofilms than in Rhodococcus erythropolis or Variovorax paradoxus biofilms. While the amount of eDNA in dual-species biofilms was of the same order of magnitude as that of of single-species biofilms, the amounts were not predictable from single-strain measurements. By the Shannon diversity index and principle components analysis of TRFLP profiles generated from 16S rRNA genes, eDNA of four-species biofilms differed significantly from either cellular or total DNA of the same biofilm. However, total DNA- and cellular DNA-based TRFLP analyses of this biofilm community yielded identical results. We conclude that extracellular DNA production in unsaturated biofilms is species dependent and that the phylogenetic information contained in this DNA pool is quantifiable and distinct from either total or cellular DNA. PMID:16151131

  11. Ignition and combustion of bulk metals under elevated, normal and reduced gravity conditions

    NASA Technical Reports Server (NTRS)

    Abbud-Madrid, Angel; Branch, Melvyn C.; Daily, John W.

    1995-01-01

    This research effort is aimed at providing further insight into this multi-variable dependent phenomena by looking at the effects of gravity on the ignition and combustion behavior of metals. Since spacecraft are subjected to higher-than-1g gravity loads during launch and reentry and to zero-gravity environments while in orbit, the study of ignition and combustion of bulk metals at different gravitational potentials is of great practical concern. From the scientific standpoint, studies conducted under microgravity conditions provide simplified boundary conditions since buoyancy is removed, and make possible the identification of fundamental ignition mechanisms. The effect of microgravity on the combustion of bulk metals has been investigated by Steinberg, et al. on a drop tower simulator. However, no detailed quantitative work has been done on ignition phenomena of bulk metals at lower or higher-than-normal gravitational fields or on the combustion characteristics of metals at elevated gravity. The primary objective of this investigation is the development of an experimental system capable of providing fundamental physical and chemical information on the ignition of bulk metals under different gravity levels. The metals used in the study, iron (Fe), titanium (Ti), zirconium (Zr), magnesium (Mg), zinc (Zn), and copper (Cu) were selected because of their importance as elements of structural metals and their simple chemical composition (pure metals instead of multi-component alloys to avoid complication in morphology and spectroscopic studies). These samples were also chosen to study the two different combustion modes experienced by metals: heterogeneous or surface oxidation, and homogeneous or gas-phase reaction. The experimental approach provides surface temperature profiles, spectroscopic measurements, surface morphology, x-ray spectrometry of metals specimens and their combustion products, and high-speed cinematography of the heating, ignition and combustion

  12. Simple rules for a "simple" nervous system? Molecular and biomathematical approaches to enteric nervous system formation and malformation.

    PubMed

    Newgreen, Donald F; Dufour, Sylvie; Howard, Marthe J; Landman, Kerry A

    2013-10-01

    We review morphogenesis of the enteric nervous system from migratory neural crest cells, and defects of this process such as Hirschsprung disease, centering on cell motility and assembly, and cell adhesion and extracellular matrix molecules, along with cell proliferation and growth factors. We then review continuum and agent-based (cellular automata) models with rules of cell movement and logistical proliferation. Both movement and proliferation at the individual cell level are modeled with stochastic components from which stereotyped outcomes emerge at the population level. These models reproduced the wave-like colonization of the intestine by enteric neural crest cells, and several new properties emerged, such as colonization by frontal expansion, which were later confirmed biologically. These models predict a surprising level of clonal heterogeneity both in terms of number and distribution of daughter cells. Biologically, migrating cells form stable chains made up of unstable cells, but this is not seen in the initial model. We outline additional rules for cell differentiation into neurons, axon extension, cell-axon and cell-cell adhesions, chemotaxis and repulsion which can reproduce chain migration. After the migration stage, the cells re-arrange as a network of ganglia. Changes in cell adhesion molecules parallel this, and we describe additional rules based on Steinberg's Differential Adhesion Hypothesis, reflecting changing levels of adhesion in neural crest cells and neurons. This was able to reproduce enteric ganglionation in a model. Mouse mutants with disturbances of enteric nervous system morphogenesis are discussed, and these suggest future refinement of the models. The modeling suggests a relatively simple set of cell behavioral rules could account for complex patterns of morphogenesis. The model has allowed the proposal that Hirschsprung disease is mostly an enteric neural crest cell proliferation defect, not a defect of cell migration. In addition

  13. Outcome after tantalum rod implantation for treatment of femoral head osteonecrosis

    PubMed Central

    Varitimidis, Sokratis E; Dimitroulias, Apostolos P; Karachalios, Theophilos S; Dailiana, Zoe H

    2009-01-01

    Background and purpose Tantalum rod implantation has recently been proposed for treatment of early stages of femoral head osteonecrosis. The purpose of our study was to report the early results of its use in pre- and post-collapse stages of the disease. Methods We studied prospectively 27 patients who underwent tantalum rod implantation for treatment of nontraumatic femoral head osteonecrosis between December 2000 and September 2005. Patients were evaluated radiologically and clinically using the Steinberg classification and the Harris hip score (HHS). Disease stage varied between stages II and IV. Mean follow-up time was 38 (15–71) months. Results 1 patient (1 hip) died 15 months after surgery for reasons unrelated to it. 13 of 26 hips remained at the same radiographic stage, and 13 deteriorated. Mean HHS improved from 49 to 85. 6 patients required conversion to total hip arthroplasty. When the procedure was used for stages III and IV, both radiological outcome and revision rates were worse than for the stage II hips. There was, however, no difference in postoperative HHS between patients at pre- and post-collapse stages at the time of initial evaluation. Survivorship, with revision to THA as the endpoint, was 70% at 6 years. Interpretation The disease process does not appear to be interrupted, but there was a significant improvement in hip function initially in most hips. Tantalum rod implantation is a safe “buy-time” technique, especially when other joint salvage procedures are not an option. Appropriate patient selection and careful rod insertion are needed for favorable results. PMID:19297785

  14. Patterns and Predictors of Mother-Adolescent Discrepancies across Family Constructs.

    PubMed

    Rote, Wendy M; Smetana, Judith G

    2016-10-01

    Parent-child discrepancies pervade the family literature; they appear in reports of relationship dynamics (e.g., conflict; Laursen et al. 1998), parent and child behaviors (e.g., monitoring; De Los Reyes et al. 2010), and individual family members' beliefs (e.g., parental legitimate authority; Smetana 2011). Discrepancies are developmentally normative (Steinberg 2001) but also may be indicators of relationship and adjustment problems for teens (Ohannessian 2012). Because of this variation, it is important to consider the extent to which parent-child discrepancies are a function of both the dyad and the family construct considered. The present study contributed to our understanding of informant discrepancies in family relationships by considering the patterning, consistency, and correlates of mother-adolescent discrepancies across three family constructs that vary in their objectivity. Using person-centered analyses, discrepancies in adolescents' and mothers' ratings of parents' right to know about teens' activities, mothers' knowledge of them, and positive mother-adolescents relationships were examined in 167 middle class, primarily European American mother-adolescent dyads (M teen age = 15.68 years, SD = .64, 53 % female). Each construct was best described by three profiles, one where adolescents' standardized ratings were consistently higher than mothers', one showing the reverse, and one revealing little disagreement. Adolescent-reported problem behavior (but not depression), behavioral and psychological control, and mothers' wellbeing significantly predicted profile membership. Most dyads maintained consistent membership in a discrepancy profile across at least two family constructs. Results contribute to understanding the different sources of discrepancies in views of the family.

  15. 2169 steel waveform experiments.

    SciTech Connect

    Furnish, Michael David; Alexander, C. Scott; Reinhart, William Dodd; Brown, Justin L.

    2012-11-01

    In support of LLNL efforts to develop multiscale models of a variety of materials, we have performed a set of eight gas gun impact experiments on 2169 steel (21% Cr, 6% Ni, 9% Mn, balance predominantly Fe). These experiments provided carefully controlled shock, reshock and release velocimetry data, with initial shock stresses ranging from 10 to 50 GPa (particle velocities from 0.25 to 1.05 km/s). Both windowed and free-surface measurements were included in this experiment set to increase the utility of the data set, as were samples ranging in thickness from 1 to 5 mm. Target physical phenomena included the elastic/plastic transition (Hugoniot elastic limit), the Hugoniot, any phase transition phenomena, and the release path (windowed and free-surface). The Hugoniot was found to be nearly linear, with no indications of the Fe phase transition. Releases were non-hysteretic, and relatively consistent between 3- and 5-mmthick samples (the 3 mm samples giving slightly lower wavespeeds on release). Reshock tests with explosively welded impactors produced clean results; those with glue bonds showed transient releases prior to the arrival of the reshock, reducing their usefulness for deriving strength information. The free-surface samples, which were steps on a single piece of steel, showed lower wavespeeds for thin (1 mm) samples than for thicker (2 or 4 mm) samples. A configuration used for the last three shots allows release information to be determined from these free surface samples. The sample strength appears to increase with stress from ~1 GPa to ~ 3 GPa over this range, consistent with other recent work but about 40% above the Steinberg model.

  16. Reassembling the Ontong Java-Manihiki-Hikurangi large igneous province: Insights and challenges

    NASA Astrophysics Data System (ADS)

    Chandler, M. T.; Wessel, P.; Taylor, B.; Sager, W. W.

    2012-12-01

    The tectonic history of ~30% of the Pacific plate south of Equator which formed during the Cretaceous Normal Supercron is difficult to establish due to its lack of a lineated magnetic anomaly pattern. This region, including the Ontong Java, Manihiki, and Hikurangi large igneous provinces, as well as the interlying Ellice Basin and Osbourn Trough, lacks active seafloor spreading centers and has thus been largely neglected by seagoing research scientists. Nonetheless, the CNS South Pacific may prove to be important for understanding Pacific history. Ontong Java's mean basement paleolatitude measurement differs from absolute plate model (APM) reconstructions for the plateau by ~8--19 degrees (Chandler et al. (2012)), indicating that either current APM models are erroneous, substantial plume drift or true polar wander occurred, or that Ontong Java experienced unrecognized motion early in its history. In support of the latter are recent findings that little to no Louisville plume drift occurred after ~70 Ma (Gee et al. (2011)), that true polar wander estimates for the ~125 Ma Ontong Java vicinity are negligible (Steinberger and Torsvik (2008)), and our recent observation of a 2:1 bias between Ontong Java's paleolatitude and latitude differences (Chandler and Wessel (2011), Chandler et al. (In prep)). These differences, computed among ODP Sites 807 and 1183 - 1187, suggest significant clockwise rotation of ~40 degrees since Ontong Java's formation at ~125 Ma. Although this rotation does not resolve the paleolatitude discrepancy it does suggest that Ontong Java's paleolatitudes may not be suitable for constraining Pacific APM. Seafloor formed at the Osbourn Trough and in the Ellice Basin make up much of the CNS South Pacific. These regions exhibit fossil spreading centers believed responsible for the breakup of Earth's largest known igneous province, the Ontong Java-Manihiki-Hikurangi super-plateau (e.g., Taylor (2006), Chandler et al. (2012)). Understanding this little

  17. The Astronomy Diagnostic Test: Comparing Your Class to Others

    NASA Astrophysics Data System (ADS)

    Hufnagel, B.; Deming, G.

    1999-05-01

    A standard diagnostic test can be a powerful tool to assess the conceptual understanding of students, as has been proven for undergraduate physics instruction over the last ten years (e.g., E.F. Redish and R.N. Steinberg 1999, Physics Today, 52:1, 24). If you are now using, or are considering adopting, a more interactive teaching style such as that used by Eric Mazur (Peer Instruction: a User's Manual, [Prentice-Hall: 1997]) or Michael Zeilik and his collaborators (1997, AJP, 65:12, 987), you may want to use a standard diagnostic test designed for undergraduate astronomy classes. Details of the validation of the ADT are at Slater et al., also presented in this session. A comparative database of ADT scores, by class and by question, can help the instructor assess student preparedness and the effectiveness of alternative teaching methods. In the spring of 1999, 19 astronomy instructors at 7 state universities, 4 community colleges, 4 liberal arts schools, 1 woman's college and 1 technical university across the USA gave the ADT to their classes once at the beginning of the course, and again at the end of the course. The average pre-course ADT scores by class from these ~ 1000 students show two surprising results: the conceptual understanding of introductory classes is about the same (34%) regardless of type of school, geographic location, or average student age. However, there is a significant gender difference, with females scoring an average of 29% and males 39%, with the standard errors both less than 1%. The Astronomy Diagnostic Test (ADT) and its comparative by-class database will be available at the National Institute for Science Education (NISE) website after 1 June 1999. This research was supported by the National Science Foundation through Grant DGE-9714489, and by the generosity of the participating astronomy instructors.

  18. CTH: A software family for multi-dimensional shock physics analysis

    SciTech Connect

    Hertel, E.S. Jr.; Bell, R.L.; Elrick, M.G.; Farnsworth, A.V.; Kerley, G.I.; McGlaun, J.M.; Petney, S.V.; Silling, S.A.; Taylor, P.A.; Yarrington, L.

    1992-12-31

    CTH is a family of codes developed at Sandia National Laboratories for modeling complex multi-dimensional, multi-material problems that are characterized by large deformations and/or strong shocks. A two-step, second-order accurate Eulerian solution algorithm is used to solve the mass, momentum, and energy conservation equations. CTH includes models for material strength, fracture, porous materials, and high explosive detonation and initiation. Viscoplastic or rate-dependent models of material strength have been added recently. The formulations of Johnson-Cook, Zerilli-Armstrong, and Steinberg-Guinan-Lund are standard options within CTH. These models rely on using an internal state variable to account for the history dependence of material response. The implementation of internal state variable models will be discussed and several sample calculations will be presented. Comparison with experimental data will be made among the various material strength models. The advancements made in modelling material response have significantly improved the ability of CTH to model complex large-deformation, plastic-flow dominated phenomena. Detonation of energetic material under shock loading conditions has been of great interest. A recently developed model of reactive burn for high explosives (HE) has been added to CTH. This model along with newly developed tabular equations-of-state for the HE reaction by-products has been compared to one- and two-dimensional explosive detonation experiments. These comparisons indicate excellent agreement of CTH predictions with experimental results. The new reactive burn model coupled with the advances in equation-of-state modeling make it possible to predict multi-dimensional burn phenomena without modifying the model parameters for different dimensionality. Examples of the features of CTH will be given. The emphasis in simulations shown will be in comparison with well characterized experiments covering key phenomena of shock physics.

  19. Extracellular DNA in single- and multiple-species unsaturated biofilms.

    PubMed

    Steinberger, R E; Holden, P A

    2005-09-01

    The extracellular polymeric substances (EPS) of bacterial biofilms form a hydrated barrier between cells and their external environment. Better characterization of EPS could be useful in understanding biofilm physiology. The EPS are chemically complex, changing with both bacterial strain and culture conditions. Previously, we reported that Pseudomonas aeruginosa unsaturated biofilm EPS contains large amounts of extracellular DNA (eDNA) (R. E. Steinberger, A. R. Allen, H. G. Hansma, and P. A. Holden, Microb. Ecol. 43:416-423, 2002). Here, we investigated the compositional similarity of eDNA to cellular DNA, the relative quantity of eDNA, and the terminal restriction fragment length polymorphism (TRFLP) community profile of eDNA in multiple-species biofilms. By randomly amplified polymorphic DNA analysis, cellular DNA and eDNA appear identical for P. aeruginosa biofilms. Significantly more eDNA was produced in P. aeruginosa and Pseudomonas putida biofilms than in Rhodococcus erythropolis or Variovorax paradoxus biofilms. While the amount of eDNA in dual-species biofilms was of the same order of magnitude as that of of single-species biofilms, the amounts were not predictable from single-strain measurements. By the Shannon diversity index and principle components analysis of TRFLP profiles generated from 16S rRNA genes, eDNA of four-species biofilms differed significantly from either cellular or total DNA of the same biofilm. However, total DNA- and cellular DNA-based TRFLP analyses of this biofilm community yielded identical results. We conclude that extracellular DNA production in unsaturated biofilms is species dependent and that the phylogenetic information contained in this DNA pool is quantifiable and distinct from either total or cellular DNA.

  20. Biomineral formation as a biosignature for microbial activities Precambrian cherts

    NASA Astrophysics Data System (ADS)

    Rincón Tomás, Blanca; Mühlen, Dominik; Hoppert, Michael; Reitner, Joachim

    2015-04-01

    In recent anoxic sediments manganese(II)carbonate minerals (e.g., rhodochrosite, kutnohorite) derive mainly from the reduction of manganese(IV) compounds by microbial anaerobic respiration. Small particles of rhodochrosite in stromatolite-like features in the Dresser chert Fm (Pilbara supergroup, W-Australia), associated with small flakes of kerogen, account for biogenic formation of the mineral in this early Archaean setting. Contrastingly, the formation of huge manganese-rich (carbonate) deposits requires effective manganese redox cycling, also conducted by various microbial processes, mainly requiring conditions of the early and late Proterozoic (Kirschvink et al., 2000; Nealson and Saffrani 1994). However, putative anaerobic pathways like microbial nitrate-dependent manganese oxidation (Hulth et al., 1999), anoxygenic photosynthesis (Johnson et al., 2013) and oxidation in UV light may facilitate manganese cycling even in a reducing atmosphere. Thus manganese redox cycling might have been possible even before the onset of oxygenic photosynthesis. Hence, there are several ways how manganese carbonates could have been formed biogenically and deposited in Precambrian sediments. Thus, the minerals may be suitable biosignatures for microbial redox processes in many respects. The hyperthermophilic archaeon Pyrobaculum islandicum produces rhodochrosite during growth on hydrogen and organic compounds and may be a putative model organism for the reduction of Mn(IV). References Hulth S, Aller RC, Gilbert F. (1999) Geochim Cosmochim Acta, 63, 49-66. Johnson JE, Webb SM, Thomas K, Ono S, Kirschvink JL, Fischer WW. (2013) Proc Natl Acad Sci USA, 110, 11238-11243. Kirschvink JL, Gaidos EJ, Bertani LE, Beukes NJ, Gutzmer J, Maepa LN, Steinberger LE. (2000) Proc Natl Acad Sci USA, 97, 1400-1405. Nealson KH, Saffarini D. (1994). Annu Rev Microbiol, 48, 311-343.

  1. Simple rules for a “simple” nervous system? Molecular and biomathematical approaches to enteric nervous system formation and malformation

    PubMed Central

    Newgreen, Donald F.; Dufour, Sylvie; Howard, Marthe J.; Landman, Kerry A.

    2013-01-01

    We review morphogenesis of the enteric nervous system from migratory neural crest cells, and defects of this process such as Hirschsprung disease, centering on cell motility and assembly, and cell adhesion and extracellular matrix molecules, along with cell proliferation and growth factors. We then review continuum and agent-based (cellular automata) models with rules of cell movement and logistical proliferation. Both movement and proliferation at the individual cell level are modeled with stochastic components from which stereotyped outcomes emerge at the population level. These models reproduced the wave-like colonization of the intestine by enteric neural crest cells, and several new properties emerged, such as colonization by frontal expansion, which were later confirmed biologically. These models predict a surprising level of clonal heterogeneity both in terms of number and distribution of daughter cells. Biologically, migrating cells form stable chains made up of unstable cells, but this is not seen in the initial model. We outline additional rules for cell differentiation into neurons, axon extension, cell-axon and cell-cell adhesions, chemotaxis and repulsion which can reproduce chain migration. After the migration stage, the cells rearrange as a network of ganglia. Changes in cell adhesion molecules parallel this, and we describe additional rules based on Steinberg's Differential Adhesion Hypothesis, reflecting changing levels of adhesion in neural crest cells and neurons. This was able to reproduce enteric ganglionation in a model. Mouse mutants with disturbances of enteric nervous system morphogenesis are discussed, and these suggest future refinement of the models. The modeling suggests a relatively simple set of cell behavioral rules could account for complex patterns of morphogenesis. The model has allowed the proposal that Hirschsprung disease is mostly an enteric neural crest cell proliferation defect, not a defect of cell migration. In addition

  2. Functional and Structural Characterization of α-(1→2) Branching Sucrase Derived from DSR-E Glucansucrase*

    PubMed Central

    Brison, Yoann; Pijning, Tjaard; Malbert, Yannick; Fabre, Émeline; Mourey, Lionel; Morel, Sandrine; Potocki-Véronèse, Gabrielle; Monsan, Pierre; Tranier, Samuel; Remaud-Siméon, Magali; Dijkstra, Bauke W.

    2012-01-01

    ΔN123-glucan-binding domain-catalytic domain 2 (ΔN123-GBD-CD2) is a truncated form of the bifunctional glucansucrase DSR-E from Leuconostoc mesenteroides NRRL B-1299. It was constructed by rational truncation of GBD-CD2, which harbors the second catalytic domain of DSR-E. Like GBD-CD2, this variant displays α-(1→2) branching activity when incubated with sucrose as glucosyl donor and (oligo-)dextran as acceptor, transferring glucosyl residues to the acceptor via a ping-pong bi-bi mechanism. This allows the formation of prebiotic molecules containing controlled amounts of α-(1→2) linkages. The crystal structure of the apo α-(1→2) branching sucrase ΔN123-GBD-CD2 was solved at 1.90 Å resolution. The protein adopts the unusual U-shape fold organized in five distinct domains, also found in GTF180-ΔN and GTF-SI glucansucrases of glycoside hydrolase family 70. Residues forming subsite −1, involved in binding the glucosyl residue of sucrose and catalysis, are strictly conserved in both GTF180-ΔN and ΔN123-GBD-CD2. Subsite +1 analysis revealed three residues (Ala-2249, Gly-2250, and Phe-2214) that are specific to ΔN123-GBD-CD2. Mutation of these residues to the corresponding residues found in GTF180-ΔN showed that Ala-2249 and Gly-2250 are not directly involved in substrate binding and regiospecificity. In contrast, mutant F2214N had lost its ability to branch dextran, although it was still active on sucrose alone. Furthermore, three loops belonging to domains A and B at the upper part of the catalytic gorge are also specific to ΔN123-GBD-CD2. These distinguishing features are also proposed to be involved in the correct positioning of dextran acceptor molecules allowing the formation of α-(1→2) branches. PMID:22262856

  3. Functional and structural characterization of α-(1->2) branching sucrase derived from DSR-E glucansucrase.

    PubMed

    Brison, Yoann; Pijning, Tjaard; Malbert, Yannick; Fabre, Émeline; Mourey, Lionel; Morel, Sandrine; Potocki-Véronèse, Gabrielle; Monsan, Pierre; Tranier, Samuel; Remaud-Siméon, Magali; Dijkstra, Bauke W

    2012-03-09

    ΔN(123)-glucan-binding domain-catalytic domain 2 (ΔN(123)-GBD-CD2) is a truncated form of the bifunctional glucansucrase DSR-E from Leuconostoc mesenteroides NRRL B-1299. It was constructed by rational truncation of GBD-CD2, which harbors the second catalytic domain of DSR-E. Like GBD-CD2, this variant displays α-(1→2) branching activity when incubated with sucrose as glucosyl donor and (oligo-)dextran as acceptor, transferring glucosyl residues to the acceptor via a ping-pong bi-bi mechanism. This allows the formation of prebiotic molecules containing controlled amounts of α-(1→2) linkages. The crystal structure of the apo α-(1→2) branching sucrase ΔN(123)-GBD-CD2 was solved at 1.90 Å resolution. The protein adopts the unusual U-shape fold organized in five distinct domains, also found in GTF180-ΔN and GTF-SI glucansucrases of glycoside hydrolase family 70. Residues forming subsite -1, involved in binding the glucosyl residue of sucrose and catalysis, are strictly conserved in both GTF180-ΔN and ΔN(123)-GBD-CD2. Subsite +1 analysis revealed three residues (Ala-2249, Gly-2250, and Phe-2214) that are specific to ΔN(123)-GBD-CD2. Mutation of these residues to the corresponding residues found in GTF180-ΔN showed that Ala-2249 and Gly-2250 are not directly involved in substrate binding and regiospecificity. In contrast, mutant F2214N had lost its ability to branch dextran, although it was still active on sucrose alone. Furthermore, three loops belonging to domains A and B at the upper part of the catalytic gorge are also specific to ΔN(123)-GBD-CD2. These distinguishing features are also proposed to be involved in the correct positioning of dextran acceptor molecules allowing the formation of α-(1→2) branches.

  4. A comparative study of the binding and inhibition of four copper-containing amine oxidases by azide: implications for the role of copper during the oxidative half-reaction.

    PubMed

    Juda, Gregory A; Shepard, Eric M; Elmore, Bradley O; Dooley, David M

    2006-07-25

    Copper amine oxidases (CuAOs) catalyze the oxidative deamination of primary amines operating through a ping-pong bi-bi mechanism. In this work, azide (an exogenous monodentate ligand) was used to probe the role of copper during the oxidative half-reaction of CuAO catalysis. The effects of azide on both the reductive and oxidative half-reactions of pea seedling amine oxidase (PSAO), the recombinant human kidney diamine oxidase (rhDAO), Arthrobacter globiformis amine oxidase (AGAO), and Pichia pastoris amine oxidase (PPLO) have been examined. For the reductive half-reaction, defined as the oxidation of amine substrate to an aldehyde, azide was discovered to exhibit either noncompetitive or competitive inhibition with respect to the amine, depending on the enzyme source. With regard to the oxidative half-reaction, defined as the reoxidation of the enzyme via reduction of O(2) to H(2)O(2), azide has been determined to exhibit competitive inhibition with respect to O(2) in PSAO with a calculated K(i) value that is in excellent agreement with the experimentally determined K(d) value for the Cu(II)-N(3)(-) complex. Azide was found to exhibit mixed-type/partially competitive inhibition with respect to substrate O(2) in rhDAO, with an apparent K(i) that is similar to the K(d) value for the Cu(II)-N(3)(-) complex. The competitive inhibition for PSAO and the partially competitive inhibition for rhDAO are consistent with O(2) interacting directly with copper during enzymatic reoxidation. For the enzymes AGAO and PPLO, pure noncompetitive and mixed-type/partially competitive inhibition is observed. K(i) values for reductive and oxidative half-reactions are equivalent and are lower than measured K(d) values for the Cu(II)-N(3)(-) complexes in oxidized and substrate-reduced forms of these enzymes. Given these observations, it appears that substantial inhibition of the reductive half-reaction occurs at the concentrations of azide used for the oxidative half-reaction experiments

  5. Biological assessment of the lower Boise River, October 1995 through January 1998, Ada and Canyon Counties, Idaho

    USGS Publications Warehouse

    Mullins, William H.

    1999-01-01

    The lower Boise River, between Lucky Peak Dam and the mouth of the river near Parma, Idaho, is adversely affected by various land- and water-use activities. To assess the biotic integrity of the river and the effects of environmental perturbations on aquatic community structure, and to provide a baseline from which to identify future changes in habitat conditions, biological data were collected from October 1995 through January 1998 and evaluated using protocols developed for the U.S. Geological Survey National Water-Quality Assessment Program. Aquatic biological communities were sampled according to the following schedule: epilithic periphyton were collected in October 1995, October 1996, and August 1997; benthic macroinvertebrates were collected in October 1995, 1996, and 1997; and fish were collected in December 1996 and August 1997. Qualitative measurements of instream and riparian habitat indicated an overall decrease in instream habitat quality in a downstream direction. Embeddedness was high at all sites but was lower at the Eckert Road site than at the downstream sites near Middleton and Parma. Silt/sand substrate increased from 17 percent at the Eckert Road site to 49 percent near the mouth of the river. The Eckert Road site had a mix of geomorphic channel units (pool/riffle/run), whereas the Middleton and Parma sites were dominated by runs with very little pool or riffle habitat. Epilithic periphyton chlorophyll-a and ashfree dry weight values tended to increase downstream to the Middleton site and decrease from Middleton to the downstream sites near Caldwell and near Parma. Benthic index of biotic integrity (B-IBI) scores for macroinvertebrates collected in 1995, 1996, and 1997 were highest at the Eckert Road site and decreased at sites downstream. IBI scores for fish collected in 1996 were similar at the Glenwood Bridge and Middleton sites (17 and 16, respectively) and were indicative of a low to moderate level of disturbance. In contrast, the IBI score

  6. A systematic analysis of acceptor specificity and reaction kinetics of five human α(2,3)sialyltransferases: Product inhibition studies illustrate reaction mechanism for ST3Gal-I

    SciTech Connect

    Gupta, Rohitesh; Matta, Khushi L.; Neelamegham, Sriram

    2016-01-15

    Sialyltransferases (STs) catalyze the addition of sialic acids to the non-reducing ends of glycoproteins and glycolipids. In this work, we examined the acceptor specificity of five human α(2,3)sialyltransferases, namely ST3Gal -I, -II, -III, -IV and -VI. K{sub M} values for each of these enzymes is presented using radioactivity for acceptors containing Type-I (Galβ1,3GlcNAc), Type-II (Galβ1,4GlcNAc), Type-III (Galβ1,3GalNAc) and Core-2 (Galβ1,3(GlcNAcβ1,6)GalNAc) reactive groups. Several variants of acceptors inhibited ST3Gal activity emphasizing structural role of acceptor in enzyme-catalyzed reactions. In some cases, mass spectrometry was performed for structural verification. The results demonstrate human ST3Gal-I catalysis towards Type-III and Core-2 acceptors with K{sub M} = 5–50 μM and high V{sub Max} values. The K{sub M} for ST3Gal-I and ST3Gal-II was 100 and 30-fold lower, respectively, for Type-III compared to Type-I acceptors. Variants of Type-I and Type-II structures characterized ST3Gal-III, -IV and -VI for their catalytic specificity. This manuscript also estimates K{sub M} for human ST3Gal-VI using Type-I and Type-II substrates. Together, these findings built a platform for designing inhibitors of STs having therapeutic potential. - Highlights: • K{sub M} for five Human ST3Gals is reported towards Type-I, Type-II & Type-III acceptors. • LC-MS simultaneously quantifies CMP-Neu5Ac & Glycans in a sialylation reaction. • Efficient Core2 sialylation indicates co-operativitiy between ST3Gal-I & C2GnT1. • ST3Gal-I inhibition study proposes iso- or random-sequential bi-bi mechanism.

  7. Undiagnosed illnesses and radioactive warfare.

    PubMed

    Duraković, Asaf

    2003-10-01

    . The analysis of the isotopic ratios identified non-depleted uranium. Studies of specimens collected in 2002 revealed uranium concentrations up to 200 times higher in the districts of Tora Bora, Yaka Toot, Lal Mal, Makam Khan Farm, Arda Farm, Bibi Mahro, Poli Cherki, and the Kabul airport than in the control population. Uranium levels in the soil samples from the bombsites show values two to three times higher than worldwide concentration levels of 2 to 3 mg/kg and significantly higher concentrations in water than the World Health Organization maximum permissible levels. This growing body of evidence undoubtedly puts the problem of prevention and solution of the DU contamination high on the priority list.

  8. Bacteriophage T4 Dam DNA-[N6-adenine]methyltransferase. Kinetic evidence for a catalytically essential conformational change in the ternary complex.

    PubMed

    Evdokimov, Alexey A; Zinoviev, Victor V; Malygin, Ernst G; Schlagman, Samuel L; Hattman, Stanley

    2002-01-04

    We carried out a steady state kinetic analysis of the bacteriophage T4 DNA-[N6-adenine]methyltransferase (T4 Dam) mediated methyl group transfer reaction from S-adenosyl-l-methionine (AdoMet) to Ade in the palindromic recognition sequence, GATC, of a 20-mer oligonucleotide duplex. Product inhibition patterns were consistent with a steady state-ordered bi-bi mechanism in which the order of substrate binding and product (methylated DNA, DNA(Me) and S-adenosyl-l-homocysteine, AdoHcy) release was AdoMet downward arrow DNA downward arrow DNA(Me) upward arrow AdoHcy upward arrow. A strong reduction in the rate of methylation was observed at high concentrations of the substrate 20-mer DNA duplex. In contrast, increasing substrate AdoMet concentration led to stimulation in the reaction rate with no evidence of saturation. We propose the following model. Free T4 Dam (initially in conformational form E) randomly interacts with substrates AdoMet and DNA to form a ternary T4 Dam-AdoMet-DNA complex in which T4 Dam has isomerized to conformational state F, which is specifically adapted for catalysis. After the chemical step of methyl group transfer from AdoMet to DNA, product DNA(Me) dissociates relatively rapidly (k(off) = 1.7 x s(-1)) from the complex. In contrast, dissociation of product AdoHcy proceeds relatively slowly (k(off) = 0.018 x s(-1)), indicating that its release is the rate-limiting step, consistent with kcat = 0.015 x s(-1). After AdoHcy release, the enzyme remains in the F conformational form and is able to preferentially bind AdoMet (unlike form E, which randomly binds AdoMet and DNA), and the AdoMet-F binary complex then binds DNA to start another methylation cycle. We also propose an alternative pathway in which the release of AdoHcy is coordinated with the binding of AdoMet in a single concerted event, while T4 Dam remains in the isomerized form F. The resulting AdoMet-F binary complex then binds DNA, and another methylation reaction ensues. This route is

  9. Measurements and ALE3D Simulations for Violence in a Scaled Thermal Explosion Experiment with LX-10 and AerMet 100 Steel

    SciTech Connect

    McClelland, M A; Maienschein, J L; Yoh, J J; deHaven, M R; Strand, O T

    2005-06-03

    We completed a Scaled Thermal Explosion Experiment (STEX) and performed ALE3D simulations for the HMX-based explosive, LX-10, confined in an AerMet 100 (iron-cobalt-nickel alloy) vessel. The explosive was heated at 1 C/h until cookoff at 182 C using a controlled temperature profile. During the explosion, the expansion of the tube and fragment velocities were measured with strain gauges, Photonic-Doppler-Velocimeters (PDVs), and micropower radar units. These results were combined to produce a single curve describing 15 cm of tube wall motion. A majority of the metal fragments were captured and cataloged. A fragment size distribution was constructed, and a typical fragment had a length scale of 2 cm. Based on these results, the explosion was considered to be a violent deflagration. ALE3D models for chemical, thermal, and mechanical behavior were developed for the heating and explosive processes. A four-step chemical kinetics model is employed for the HMX while a one-step model is used for the Viton. A pressure-dependent deflagration model is employed during the expansion. The mechanical behavior of the solid constituents is represented by a Steinberg-Guinan model while polynomial and gamma-law expressions are used for the equation of state of the solid and gas species, respectively. A gamma-law model is employed for the air in gaps, and a mixed material model is used for the interface between air and explosive. A Johnson-Cook model with an empirical rule for failure strain is used to describe fracture behavior. Parameters for the kinetics model were specified using measurements of the One-Dimensional-Time-to-Explosion (ODTX), while measurements for burn rate were employed to determine parameters in the burn front model. The ALE3D models provide good predictions for the thermal behavior and time to explosion, but the predicted wall expansion curve is higher than the measured curve. Possible contributions to this discrepancy include inaccuracies in the chemical models

  10. Crustal Footprint of the Hainan Plume beneath Southeast China

    NASA Astrophysics Data System (ADS)

    Liu, H.; Chen, F.; Leng, W.; Zhang, H.

    2016-12-01

    A hotspot track is an age-progressive line of volcanos that is connected to a hotspot that may have resulted from interactions between the lithosphere and a deep-seated mantle plume [Campbell and Griffiths, 1990; Richards et al., 1989]. Although global and regional seismic tomography results have revealed the presence of a mantle plume beneath Hainan Island [Lebedev et al., 2003; Lei et al., 2009; Huang, 2014], there is little evidence for a hotspot track associated with the Hainan plume. Here, a joint inversion of seismology and gravity data was performed with the receiver function method, and the results show that a linear corridor of seismic velocity anomalies at the base of the crust is located northeast of Hainan Island beneath southeast China. Geodynamic modeling demonstrates that this corridor could have formed by the interactions between a mantle plume and the continental lithosphere with a weak lower crust. Volcanic age distributions further suggest that this track likely formed in the Cenozoic, which constrains the average plate velocities of the South China Block during the Cenozoic to 2-6 cm/yr to the northeast. These results provide an independent reference frame for the motion history of the Eurasia plate in the Cenozoic. References 1. Campbell I H, Griffiths R W. Implications of mantle plume structure for the evolution of flood basalts [J]. Earth and Planetary Science Letters, 1990, 99(1): 79-93. 2. Richards M A, Duncan R A, Courtillot V E. Flood basalts and hot-spot tracks: plume heads and tails [J]. Science, 1989, 246(4926): 103-107. 3. Lebedev S, Nolet G. Upper mantle beneath Southeast Asia from S velocity tomography [J]. Journal of Geophysical Research: Solid Earth (1978-2012), 2003, 108(B1). 4. Lei J, Zhao D, Steinberger B, et al. New seismic constraints on the upper mantle structure of the Hainan plume [J]. Physics of the Earth and Planetary Interiors, 2009, 173(1): 33-50. 5. Huang J. P-and S-wave tomography of the Hainan and surrounding

  11. Accessing ultrahigh-pressure, quasi-isentropic states of matter

    SciTech Connect

    Lorenz, K.T.; Edwards, M.J.; Glendinning, S.G.; Jankowski, A.F.; McNaney, J.; Pollaine, S.M.; Remington, B.A.

    2005-05-15

    A new approach to the study of material strength of metals at extreme pressures has been developed on the Omega laser, using a ramped plasma piston drive. The laser drives a shock through a solid plastic reservoir that unloads at the rear free surface, expands across a vacuum gap, and stagnates on the metal sample under study. This produces a gently increasing ram pressure, compressing the sample nearly isentropically. The peak pressure on the sample, inferred from interferometric measurements of velocity, can be varied by adjusting the laser energy and pulse length, gap size, and reservoir density, and obeys a simple scaling relation [J. Edwards et al., Phys. Rev. Lett. 92, 075002 (2004)]. In an important application, using in-flight x-ray radiography, the material strength of solid-state samples at high pressure can be inferred by measuring the reductions in the growth rates (stabilization) of Rayleigh-Taylor unstable interfaces. This paper reports the first attempt to use this new laser-driven, quasi-isentropic technique for determining material strength in high-pressure solids. Modulated foils of Al-6061-T6 were accelerated and compressed to peak pressures of {approx}200 kbar. Modulation growth was recorded at a series of times after peak acceleration and well into the release phase. Fits to the growth data, using a Steinberg-Guinan constitutive strength model, give yield strengths 38% greater than those given by the nominal parameters for Al-6061-T6. Calculations indicate that the dynamic enhancement to the yield strength at {approx}200 kbar is a factor of {approx}3.6x over the ambient yield strength of 2.9 kbar. Experimental designs based on this drive developed for the National Ignition Facility laser [W. Hogan, E. Moses, B. Warner, M. Sorem, and J. Soures, Nuclear Fusion 41, 567 (2001)] predict that solid-state samples can be quasi-isentropically driven to pressures an order of magnitude higher than on Omega, accessing new regimes of dense, high

  12. Possible Signatures Of Kelvin-Helmholtz Waves On The Dusk Flank Of The Kronian Magnetopause

    NASA Astrophysics Data System (ADS)

    Cutler, Jack; Masters, Adam; Dougherty, Michele; Lucek, Elizabeth; Kanani, Sheila

    2010-05-01

    A comprehensive survey of crossings of both Saturn's magnetopause and bow shock on the dusk side between January 2007 and December 2007 was compiled, using data from the Cassini fluxgate magnetometer and the Cassini electron spectrometer. Bow shock and magnetopause crossings were determined by the criteria discussed in Masters et al., 2008 and Masters et al., 2009 [1] respectively. 396 magnetopause crossings and 165 bow shock crossings were identified with large spatial variation; the high temporal frequency of crossings combined with the large radial variation was indicative of highly dynamic boundaries. A set of magnetopause crossings occurring near the nose of the magnetopause on the 30th June and 1st July 2007 were then analysed using minimum variance analysis (MVA) of the magnetic field vectors over the crossing interval to determine the direction of the boundary normal at each crossing. Using MVA analysis again to calculate the maximum variance direction of the magnetopause normals, I found a clear preferred direction of variance of the normals. The normals were found to deviate by an average of 30° about the average normal direction in the plane of maximum variance, but only by 12° in the perpendicular plane. The observed oscillation of dawn side crossing normals (Masters et al., 2009) was not present throughout the whole dusk set, but was present for subsets, which is suggestive of wave activity. Considering the orientation between the magnetospheric magnetic field and the direction of maximum variance of the normals, the Kelvin-Helmholtz (K-H) instability is the likely driving force of these boundary perturbations. Current work involves analyzing two further magnetopause crossing sets, one further dusk-ward and one closer to noon (SLT), to identify whether K-H waves are also present at these locations. [1] Masters, A.; McAndrews, H. J.; Steinberg, J. T.; Thomsen, M. F.; Arridge, C. S.; Dougherty, M. K.; Billingham, L.; Schwartz, S. J.; Sergis, N

  13. You have a message! Social networking as a motivator for FLS training.

    PubMed

    Petrucci, Andrea M; Kaneva, Pepa; Lebedeva, Ekaterina; Feldman, Liane S; Fried, Gerald M; Vassiliou, Melina C

    2015-01-01

    Despite evidence supporting the value of the Fundamentals of Laparoscopic Surgery (FLS) curriculum, surgical educators still find it challenging to motivate residents to practice. Wiggio is an online networking and collaboration tool that allows learners to track performance, see what their peers are doing, and send and receive updates. The purpose of this study was to assess whether using Wiggio increases practice and improves performance of the FLS manual skills. After baseline FLS testing, residents were randomized into control (C) and Wiggio (W) groups. The practice events, time spent practicing, and best scores were recorded. Residents in the W group interacted with each other via the Wiggio website. The website moderator sent motivational messages, calendar reminders, and FLS-related articles. The best times and progress graphs for each resident were also posted online. After 4 weeks, all residents underwent final FLS testing and filled out a questionnaire. The study was performed in a tertiary care center, at the Steinberg-Bernstein Centre for Minimally Invasive Surgery at the Montreal General Hospital. Postgraduate year-1 and postgraduate year-2 general surgery residents with no or minimal FLS simulator experience were included. Of the 15 eligible residents, 14 participated, with 7 residents in each group. The FLS scores were similar at baseline (C = 56.9 [±14.2], W = 57. 6 [±14.7]; p = 0.93). During the study period, twice as many residents in the W group practiced compared with those in the C group (4 vs 2); W-group residents reported more practice events than the C-group residents did (14 vs 4) and spent more time practicing in the laboratory (1035 vs 480 minutes). These results did not reach statistical significance. During practice sessions, proficiency scores were achieved for 40% of the tasks in the W group compared with 8.6% in the C group; however, this difference was also not significant. There was no difference in the FLS scores in both groups

  14. Molecular mechanisms of Alzheimer disease protection by the A673T allele of amyloid precursor protein.

    PubMed

    Maloney, Janice A; Bainbridge, Travis; Gustafson, Amy; Zhang, Shuo; Kyauk, Roxanne; Steiner, Pascal; van der Brug, Marcel; Liu, Yichin; Ernst, James A; Watts, Ryan J; Atwal, Jasvinder K

    2014-11-07

    Pathogenic mutations in the amyloid precursor protein (APP) gene have been described as causing early onset familial Alzheimer disease (AD). We recently identified a rare APP variant encoding an alanine-to-threonine substitution at residue 673 (A673T) that confers protection against development of AD (Jonsson, T., Atwal, J. K., Steinberg, S., Snaedal, J., Jonsson, P. V., Bjornsson, S., Stefansson, H., Sulem, P., Gudbjartsson, D., Maloney, J., Hoyte, K., Gustafson, A., Liu, Y., Lu, Y., Bhangale, T., Graham, R. R., Huttenlocher, J., Bjornsdottir, G., Andreassen, O. A., Jönsson, E. G., Palotie, A., Behrens, T. W., Magnusson, O. T., Kong, A., Thorsteinsdottir, U., Watts, R. J., and Stefansson, K. (2012) Nature 488, 96-99). The Ala-673 residue lies within the β-secretase recognition sequence and is part of the amyloid-β (Aβ) peptide cleavage product (position 2 of Aβ). We previously demonstrated that the A673T substitution makes APP a less favorable substrate for cleavage by BACE1. In follow-up studies, we confirm that A673T APP shows reduced cleavage by BACE1 in transfected mouse primary neurons and in isogenic human induced pluripotent stem cell-derived neurons. Using a biochemical approach, we show that the A673T substitution modulates the catalytic turnover rate (V(max)) of APP by the BACE1 enzyme, without affecting the affinity (K(m)) of the APP substrate for BACE1. We also show a reduced level of Aβ(1-42) aggregation with A2T Aβ peptides, an observation not conserved in Aβ(1-40) peptides. When combined in a ratio of 1:9 Aβ(1-42)/Aβ(1-40) to mimic physiologically relevant mixtures, A2T retains a trend toward slowed aggregation kinetics. Microglial uptake of the mutant Aβ(1-42) peptides correlated with their aggregation level. Cytotoxicity of the mutant Aβ peptides was not dramatically altered. Taken together, our findings demonstrate that A673T, a protective allele of APP, reproducibly reduces amyloidogenic processing of APP and also mildly decreases A

  15. The First Year of Solar-Wind Data From the GENESIS Mission

    NASA Astrophysics Data System (ADS)

    Wiens, R. C.; Barraclough, B. L.; Steinberg, J. T.; Reisenfeld, D. B.; Neugebauer, M.; Burnett, D. S.

    2002-12-01

    The GENESIS mission was launched in August, 2001, and has been in an L1 halo orbit for over a year. The primary purpose of the mission is to collect solar-wind samples that will be returned to Earth in 2004 for high-precision isotopic and elemental analyses. GENESIS uses conventional ion and electron spectrometers to record solar-wind conditions during collection, and to make real-time determinations of the solar-wind regimes to facilitate collection of separate samples of interstream (IS), coronal hole (CH), and coronal mass ejection (CME) flows. Of particular interest is the use of a bi-directional electron (BDE) index to determine the presence of CMEs. And although GENESIS lacks a magnetometer, the field vector, with sign ambiguity, is determined by the electron direction, and matches other spacecraft magnetometer data well. GENESIS in-situ data and on-board regime determinations are available on the web. The data from Fall, 2001 were characterized by numerous CME regimes (comprising 32% of the time in the 4th quarter, based on the on-board algorithm), with little CH flow (only 2%). A strong CH flow was observed every solar rotation from mid-January through late May. June was quiet, nearly all IS flow. The first and second quarters of 2002 were approximately 28% CME flow, with CH flow dropping from 18% to 6%. The discovery of unexpectedly noticeable BDE signals during CH flows at 1 AU (Steinberg et al., 2002) caused us early on to modify our regime selection algorithm to accommodate these. The on-board algorithm intentionally errs on the side of overestimating CME flows in order to keep the CH sample more pure. Comparisons have been made of various compositional parameters determined by Genesis (Barraclough et al., this meeting) and by ACE SWICS (Reisenfeld et al., this meeting) for times corresponding to the Genesis collection periods for each of the three regimes. The Genesis L1 halo orbit is ~0.8 x 0.25 million km radius, somewhat larger than the ~0.3 x 0

  16. Hydrocode Models of the Response of a Simplified Asteroid Bennu to a Stand-Off Nuclear Deflection Attempt

    NASA Astrophysics Data System (ADS)

    Plesko, C. S.; Ferguson, J. M.; Gisler, G. R.; Heberling, T.; Weaver, R.

    2016-12-01

    101955 Bennu is the 2016 NASA OSIRIS-REx sample return mission target. Current knowledge of Bennu is as good or better than what might be available for a potentially hazardous asteroid during mitigation planning. It is a 492-m-diameter spheroidal B-type carbonaceous asteroid similar to CI and CM meteorites (Hergenrother et al. 203, 2014). Bennu is potentially hazardous, with an impact probability of 1:37000 in the late 2100's, according to the JPL SENTRY database. We are modeling a deflection attempt by nuclear stand-off burst against a hypothetical Bennu-like asteroid as part of the NASA-NNSA inter-agency collaboration on impact hazard mitigation. The collaboration agreed on model initial conditions at our December 2016 Technical Interchange Meeting. We agreed that the target's initial conditions would be a simplified analog of Bennu, so the model could be run with the same properties in all of the codes used within the collaboration. The models use a 500-m-diameter sphere of pure SiO2 reduced to a density of 1 g/cm^3 using a ramp porosity model, and a Steinberg-Guinan strength model that uses median strength values for granular regolith used in OSIRIS-REx mission planning supplemented by lunar regolith values. In order to reduce the computational load of calculating energy transport from a 1 Mt stand-off nuclear burst above the target surface, we assume uniform heating of a thin spherical cap of material to a uniform temperature. Separate calculations were conducted with the heated cap's temperatures set to T = 1, 2, 5, 10, and 30 eV. One set of models ran in a purely hydrodynamical mode, while a second set was run with x-ray transport enabled to allow the heated material to radiatively cool in order to determine the importance of energy loss through re-radiation as a function of temperature. We find that re-radiation does not have a strong effect on momentum in these models. A third set explores assumptions about the thickness of the heated material, which

  17. Seismic and Geodynamic Constraints on Compositional Heterogeneity in the Lower Mantle: Implications for Deeply-Rooted Hot Upwellings Under the African and Pacific Plates

    NASA Astrophysics Data System (ADS)

    Forte, A. M.; Glisovic, P.; Rowley, D. B.; Simmons, N. A.; Grand, S. P.; Lu, C.

    2014-12-01

    We present the results of a series of tests that probe the possible existence of compositionally distinct material in the central core of the LLSVPs under the African and Pacific plates using tomography-based mantle flow models that employ several independently-derived viscosity profiles (Mitrovica & Forte 2004, Behn et al. 2004, Steinberger & Calderwood 2006, Forte et al. 2010). We also consider four global tomography models derived from seismic shear velocity data alone (Grand 2002, Panning & Romanowicz 2006, Kustowski et al. 2008, Ritsema et al. 2011). The possible combinations of viscosity and tomography models yield 16 different tests for compositional heterogeneity inside the LLSVPs. In all tests we begin with a mineral physical scaling between lower-mantle shear velocity and density anomalies that assumes thermal effects are dominant everywhere, including within the LLSVPs. We find it is not possible, in any of the tests, to obtain a satisfactory fit to surface geodynamic data, especially the global, long-wavelength gravity anomalies and space-geodetic inferences of excess CMB flattening with a purely thermal interpretation of lower-mantle heterogeneity. If we introduce compositionally-distinct material in the central portions of the LLSVPs, all tests show a notable improvement in the fit to the gravity anomaly and CMB ellipticity data. An optimal reconciliation of the gravity and CMB data is obtained by extending compositional heterogeneity upwards, with maximum-amplitude in the seismic D"-layer and tapering off to negligible values in the mid-mantle. A robust assessment of the dynamical impact of this deeply-rooted compositional heterogeneity is obtained with maps of "mean" convective flow, by averaging the results of all 16 test cases. We find (see map below) dominant lower-mantle upwellings below the axis of the East Pacific Rise (EPR), and under the Caroline Islands in the Western Pacific. Under the African plate we find large-scale upwellings under the

  18. Accessing ultrahigh-pressure, quasi-isentropic states of mattera)

    NASA Astrophysics Data System (ADS)

    Lorenz, K. T.; Edwards, M. J.; Glendinning, S. G.; Jankowski, A. F.; McNaney, J.; Pollaine, S. M.; Remington, B. A.

    2005-05-01

    A new approach to the study of material strength of metals at extreme pressures has been developed on the Omega laser, using a ramped plasma piston drive. The laser drives a shock through a solid plastic reservoir that unloads at the rear free surface, expands across a vacuum gap, and stagnates on the metal sample under study. This produces a gently increasing ram pressure, compressing the sample nearly isentropically. The peak pressure on the sample, inferred from interferometric measurements of velocity, can be varied by adjusting the laser energy and pulse length, gap size, and reservoir density, and obeys a simple scaling relation [J. Edwards et al., Phys. Rev. Lett. 92, 075002 (2004)]. In an important application, using in-flight x-ray radiography, the material strength of solid-state samples at high pressure can be inferred by measuring the reductions in the growth rates (stabilization) of Rayleigh-Taylor unstable interfaces. This paper reports the first attempt to use this new laser-driven, quasi-isentropic technique for determining material strength in high-pressure solids. Modulated foils of Al-6061-T6 were accelerated and compressed to peak pressures of ˜200kbar. Modulation growth was recorded at a series of times after peak acceleration and well into the release phase. Fits to the growth data, using a Steinberg-Guinan constitutive strength model, give yield strengths 38% greater than those given by the nominal parameters for Al-6061-T6. Calculations indicate that the dynamic enhancement to the yield strength at ˜200kbar is a factor of ˜3.6× over the ambient yield strength of 2.9kbar. Experimental designs based on this drive developed for the National Ignition Facility laser [W. Hogan, E. Moses, B. Warner, M. Sorem, and J. Soures, Nuclear Fusion 41, 567 (2001)] predict that solid-state samples can be quasi-isentropically driven to pressures an order of magnitude higher than on Omega, accessing new regimes of dense, high-pressure matter.

  19. A New US National Science Foundation funded Education and Outreach Director's Initiative

    NASA Astrophysics Data System (ADS)

    Steinberg, Daniel

    The US National Science Foundation (NSF) has a broader impact requirement for all research proposals, and the proposals are evaluated based on this and the intellectual merit of the research proposed. Historically, NSF and other US government funded research organizations such as NASA have had similar Education and Public Outreach (EPO) requirements and each have endorsed an important community of outreach professionals to facilitate broader impact goals. NSF funds Materials Research Science and Engineering Centers (MRSECs) to support interdisciplinary and multidisciplinary materials research and education which strives for the highest quality while addressing fundamental problems in science and engineering that are important to society. The MRSEC program of consists nearly 30 center in interdisciplinary research and education and calls for coordination of the overall effort among Centers. All MR- SEC's have education directors and coordinators responsible for the critical task of developing education programs. MRSECs offer educational outreach programs in science and technology for elementary, middle, and high school (K-12) students and teachers, undergraduates, and general public that communicate the research of their centers with the general public with the aim of improving science literacy. Recently, at the Fall, 2007 Materials Research Society meeting in Boston the MRSEC outreach directors were asked to create an education network to provide leadership in the area of materials education and outreach. The author Dan Steinberg was chosen by his colleagues to act as founding chair/president of this new organization which represents a collaborative effort of all MRSEC education directors. Part of our mission is to reach out to, but not duplicate the efforts of other organizations concerned with bringing real science research effectively into science and engineering education initiatives. In this session, we will present an update on the development of this new

  20. A one-month study of the zooplankton community at a fixed station in the Ligurian Sea: the potential impact of the species composition on the mineralization of organic matter

    NASA Astrophysics Data System (ADS)

    Mousseau, L.; Lefevre, D.; Narcy, F.; Nival, P.; Andersen, V.

    2009-01-01

    The cruise project was designed to study temporal variations of the ecosystem during the summer-autumn transition and focused on the part played by zooplankton as top-down controllers, and the relative importance of top-down versus bottom-up controls. Zooplankton should play a key role both in the vertical transfer of particulate organic matter and in the mineralisation of organic matter. Although the importance of species diversity is well recognized, the impact of diversity on carbon fluxes is rarely considered. Trophic roles of zooplankton range from strict herbivory to strict carnivory, with all possible combinations (i.e. omnivory) between these two extremes. Feeding strategies are also very diverse, for example, active predators, passive filter feeders or suspension feeders co-exist (Bamstedt at al., 2000). As the metabolic cost of these different trophic roles and ways of feeding should be different, a physiological diversity must be considered in any assessment of the role of zooplankton in the flux of organic matter (e.g. Longhurts and Harrison, 1989). At a minimum,, species and functional diversities contribute to the diversity of exported organic matter (Steinberg et al., 2000; Madin et al., 2001). Fecal pellets, the organic matter egested by zooplankton, differ in form, size and weight, and hence in their sedimentation and degradation rates (Turner, 2002). The downward flux of organic matter thus depends on not only on physical and chemical processes but also on biological variables. The area sampled, located in the central part of the Ligurian Sea is next to the DYFAMED site, a time-series station monthly monitored for several years now. The zone is considered to be oligotrophic and protected from strong advective processes (Andersen and Prieur, 2000). The two cruises DYNAmic of the rapid PROCess (DYNAPROC 1 in May 1995 and DYNAPROC 2, the present study) were devoted to factors controlling the vertical flux of matter on short time scales. The aim of

  1. New Pacific-Nazca(Farallon) finite rotation poles

    NASA Astrophysics Data System (ADS)

    Wilder, D.; Naar, D.; Tebbens, S.; Wessel, P.; Harada, Y.; Johnson, K.; Pyle, D.; Ray, J.; Mahoney, J.; Duncan, R.

    2003-04-01

    We present 9 new finite rotation poles for the Pacific-Nazca (and previous Farallon) plates for the magnetic anomalies listed below in an effort to provide the best possible relative motion model for the Pacific and Nazca plates during the time that the Easter-Salas y Gomez hotspot formed the volcanic chain that extends from about the EPR to the Peru-Chile Trench. This relative motion model allows calculation of the Nazca-hotspot finite rotations by adding the Nazca-Pacific to the Pacific-hotspot finite rotations. The Nazca-hotpsot motion model is used to compare to the Ar radiometric ages (Duncan et al., this session) of samples we collected in Nov-Dec 2001 on the R/V Revelle. This comparision provides a test of hotspot fixity and predictions derived by mantle circulation models (Steinberger, 2002; Duncan et al., this session). As part of this tectonic modeling effort, new magnetic isochrons have been identified and compared to previous interpretations in the dissertations of Liu (1996) and Cornaglia (1995). As expected, the time period between magnetic anomaly 5d and 6c is comprised of a major plate boundary reorganizations involving large changes in relative plate motion and the formation of microplates (including the Mendoza paleomicroplate), preventing Pacific-Nazca finite rotations to be calculated during that time period without additional magnetic and bathmetry data. Listed below are preliminary pole locations and rotation angles as we finalize our analyses of the magnetic and altimetry data from this region. Magnetic Anomaly, Latitude, Longitude, Degrees of Finite Rotation: 3a,-56.402,86.377,9.68; 4a,-58.229,86.357,13.18; 5o, -60.012,86.728,16.86; 5aa,-61.997,87.206,19.63; 5b,-64.519,83.614,23.10l; 5d,-72.215,89.268,26.49; 6c,-59.681,88.984,38.44; 7y,-61.151,88.859, 38.88; 10y,-65.595,82.612,43.83.

  2. Deep structure and origin of active volcanoes in China

    NASA Astrophysics Data System (ADS)

    Zhao, D.

    2010-12-01

    Recent geophysical studies have provided important constraints on the deep structure and origin of the active intraplate volcanoes in Mainland China. Magmatism in the western Pacific arc and back-arc areas is caused by the corner flow in the mantle wedge and dehydration of the subducting slab (e.g., Zhao et al., 2009a), while the intraplate magmatism in China has different origins. The active volcanoes in Northeast China (such as the Changbai and Wudalianchi) are caused by hot upwelling in the big mantle wedge (BMW) above the stagnant slab in the mantle transition zone and deep slab dehydration as well (Zhao et al., 2009b). The Tengchong volcano in Southwest China is caused by a similar process in the BMW above the subducting Burma microplate (or Indian plate) (Lei et al., 2009a). The Hainan volcano in southernmost China is a hotspot fed by a lower-mantle plume which may be associated with the Pacific and Philippine Sea slabs' deep subduction in the east and Indian slab's deep subduction in the west down to the lower mantle (Lei et al., 2009b; Zhao, 2009). The stagnant slab finally collapses down to the bottom of the mantle, which can trigger the upwelling of hot mantle materials from the lower mantle to the shallow mantle beneath the subducting slabs and may cause the slab-plume interactions (Zhao, 2009). References Lei, J., D. Zhao, Y. Su, 2009a. Insight into the origin of the Tengchong intraplate volcano and seismotectonics in southwest China from local and teleseismic data. J. Geophys. Res. 114, B05302. Lei, J., D. Zhao, B. Steinberger et al., 2009b. New seismic constraints on the upper mantle structure of the Hainan plume. Phys. Earth Planet. Inter. 173, 33-50. Zhao, D., 2009. Multiscale seismic tomography and mantle dynamics. Gondwana Res. 15, 297-323. Zhao, D., Z. Wang, N. Umino, A. Hasegawa, 2009a. Mapping the mantle wedge and interplate thrust zone of the northeast Japan arc. Tectonophysics 467, 89-106. Zhao, D., Y. Tian, J. Lei, L. Liu, 2009b. Seismic

  3. Muscle-specific AMPK β1β2-null mice display a myopathy due to loss of capillary density in nonpostural muscles

    PubMed Central

    Thomas, Melissa M.; Wang, David C.; D'Souza, Donna M.; Krause, Matthew P.; Layne, Andrew S.; Criswell, David S.; O'Neill, Hayley M.; Connor, Michael K.; Anderson, Judy E.; Kemp, Bruce E.; Steinberg, Gregory R.; Hawke, Thomas J.

    2014-01-01

    AMP-activated protein kinase (AMPK) is a master regulator of metabolism. While muscle-specific AMPK β1β2 double-knockout (β1β2M-KO) mice display alterations in metabolic and mitochondrial capacity, their severe exercise intolerance suggested a secondary contributor to the observed phenotype. We find that tibialis anterior (TA), but not soleus, muscles of sedentary β1β2M-KO mice display a significant myopathy (decreased myofiber areas, increased split and necrotic myofibers, and increased centrally nucleated myofibers. A mitochondrial- and fiber-type-specific etiology to the myopathy was ruled out. However, β1β2M-KO TA muscles displayed significant (P<0.05) increases in platelet aggregation and apoptosis within myofibers and surrounding interstitium (P<0.05). These changes correlated with a 45% decrease in capillary density (P<0.05). We hypothesized that the β1β2M-KO myopathy in resting muscle resulted from impaired AMPK-nNOSμ signaling, causing increased platelet aggregation, impaired vasodilation, and, ultimately, ischemic injury. Consistent with this hypothesis, AMPK-specific phosphorylation (Ser1446) of nNOSμ was decreased in β1β2M-KO compared to wild-type (WT) mice. The AMPK-nNOSμ relationship was further demonstrated by administration of 5-aminoimidazole-4-carboxamide 1-β-d-ribofuranoside (AICAR) to β1β2-MKO muscles and C2C12 myotubes. AICAR significantly increased nNOSμ phosphorylation and nitric oxide production (P<0.05) within minutes of administration in WT muscles and C2C12 myotubes but not in β1β2M-KO muscles. These findings highlight the importance of the AMPK-nNOSμ pathway in resting skeletal muscle.—Thomas, M. M., Wang, D. C., D'Souza, D. M., Krause, M. P., Layne, A. S., Criswell, D. S., O'Neill, H. M., Connor, M. K., Anderson, J. E., Kemp, B. E., Steinberg, G. R., and Hawke, T. J. Muscle-specific AMPK β1β2-null mice display a myopathy due to loss of capillary density in nonpostural muscles. PMID:24522207

  4. ALE3D Simulation and Measurement of Violence in a Fast Cookoff Experiment for LX-10

    SciTech Connect

    McClelland, M A; Maienschein, J L; Howard, W M; deHaven, M R

    2006-05-23

    Fast cookoff is of interest in the areas of fire hazard reduction and the development of directed energy systems for defense. During a fast cookoff (thermal explosion), high heat fluxes cause rapid temperature increases and ignition in thin boundary layers. We are developing ALE3D models to describe the thermal, chemical, and mechanical behavior during the heating, ignition, and explosive phases. The candidate models and numerical strategies are being evaluated using benchmark cookoff experiments. Fast cookoff measurements were made in a Scaled-Thermal-Explosion-eXperiment (STEX) for LX-10 (94.7% HMX, 5.3% Viton A) confined in a 4130 steel tube with reinforced end caps. Gaps were present at the side and top of the explosive charge to allow for thermal expansion. The explosive was heated until explosion using radiant heaters. Temperatures were measured using thermocouples positioned on the tube wall and in the explosive. During the explosion, the tube expansion and fragment velocities were measured with strain gauges, Photonic-Doppler-Velocimeters (PDVs), and micropower radar units. A fragment size distribution was constructed from fragments captured in Lexan panels. ALE3D models for chemical, thermal, and mechanical behavior were developed for the heating and explosive processes. A multi-step chemical kinetics model is employed for the HMX while a one-step model is used for the Viton. A pressure-dependent deflagration model is employed during the expansion. A Steinberg-Guinan model represents the mechanical behavior of the solid constituents while polynomial and gamma-law expressions are used for the equation of state of the solid and gas species, respectively. Parameters for the kinetics model were specified using measurements of the One-Dimensional-Time-to-Explosion (ODTX), while measurements for burn rate were employed to determine parameters in the burn front model. The simulations include radiative and conductive transport across the dynamic gaps between the

  5. The enzymatic and antioxidative stress response of Lemna minor to copper and a chloroacetamide herbicide.

    PubMed

    Obermeier, Michael; Schröder, Christian A; Helmreich, Brigitte; Schröder, Peter

    2015-12-01

    Lemna minor L., a widely used model plant for toxicity tests has raised interest for its application to phytoremediation due to its rapid growth and ubiquitous occurrence. In rural areas, the pollution of water bodies with heavy metals and agrochemicals poses a problem to surface water quality. Among problematic compounds, heavy metals (copper) and pesticides are frequently found in water bodies. To establish duckweed as a potential plant for phytoremediation, enzymatic and antioxidative stress responses of Lemna minor during exposure to copper and a chloroacetamide herbicide were investigated in laboratory studies. The present study aimed at evaluating growth and the antioxidative and glutathione-dependent enzyme activity of Lemna plants and its performance in a scenario for phytoremediation of copper and a chloroacetamide herbicide. Lemna minor was grown in Steinberg medium under controlled conditions. Plants were treated with CuSO4 (ion conc. 50 and 100 μg/L) and pethoxamide (1.25 and 2.5 μg/L). Measurements following published methods focused on plant growth, oxidative stress, and basic detoxification enzymes. Duckweed proved to survive treatment with the respective concentrations of both pollutants very well. Its growth was inhibited scarcely, and no visible symptoms occurred. On the cellular basis, accumulation of O2(-) and H2O2 were detected, as well as stress reactions of antioxidative enzymes. Duckweed detoxification potential for organic pollutants was high and increased significantly with incubation. Pethoxamide was found to be conjugated with glutathione. Copper was accumulated in the fronds at high levels, and transient oxidative defense reactions were triggered. This work confirms the significance of L. minor for the removal of copper from water and the conjugation of the selective herbicide pethoxamide. Both organic and inorganic xenobiotics induced different trends of enzymatic and antioxidative stress response. The strong increase of stress

  6. Age systematics of two young en echelon Samoan volcanic trails

    NASA Astrophysics Data System (ADS)

    Koppers, Anthony A. P.; Russell, Jamie A.; Roberts, Jed; Jackson, Matthew G.; Konter, Jasper G.; Wright, Dawn J.; Staudigel, Hubert; Hart, Stanley R.

    2011-07-01

    The volcanic origin of the Samoan archipelago can be explained by one of three models, specifically, by a hot spot forming over a mantle plume, by lithospheric extension resulting from complex subduction tectonics in the region, or by a combination of these two processes, either acting sequentially or synchronously. In this paper, we present results of 36 high-resolution 40Ar/39Ar incremental heating age analyses for the initial (submarine) phase of Samoan volcanoes, ranging from 13.2 Ma for the westernmost Samoan seamounts to 0.27 Ma in the eastern Samoan volcanic province. Taken as a whole, our new age data point to a hot spot origin for the shield-building volcanism in the Samoan lineament, whereby seamounts younger than 5 Ma are consistent with a model of constant 7.1 cm/yr plate motion, analogous to GPS measurements for the Pacific Plate in this region. This makes our new 40Ar/39Ar ages of the submarine basalts all older compared to recent absolute plate motion (APM) models by Wessel et al. (2008), which are based on the inversion of twelve independent seamount trails in the Pacific relative to a fixed reference frame of hot spots and which predict faster plate motions of around 9.3 cm/yr in the vicinity of Samoa. The Samoan ages are also older than APM models by Steinberger et al. (2004) taking into account the motion of hot spots in the Pacific alone or globally. The age systematics become more complicated toward the younger end of the Samoan seamount trail, where its morphology bifurcates into two en echelon subtracks, termed the VAI and MALU trends, as they emanate from two eruptive centers at Vailulu'u and Malumalu seamount, respectively. Spaced ˜50 km apart, the VAI and MALU trends have distinct geochemical characters and independent but overlapping linear 40Ar/39Ar age progressions since 1.5 Ma. These phenomena are not unique to Samoa, as they have been observed at the Hawaiian hot spot, and can be attributed to a geochemical zoning in its underlying

  7. A Report on the Validation of Beryllium Strength Models

    SciTech Connect

    Armstrong, Derek Elswick

    2016-02-05

    This report discusses work on validating beryllium strength models with flyer plate and Taylor rod experimental data. Strength models are calibrated with Hopkinson bar and quasi-static data. The Hopkinson bar data for beryllium provides strain rates up to about 4000 per second. A limitation of the Hopkinson bar data for beryllium is that it only provides information on strain up to about 0.15. The lack of high strain data at high strain rates makes it difficult to distinguish between various strength model settings. The PTW model has been calibrated many different times over the last 12 years. The lack of high strain data for high strain rates has resulted in these calibrated PTW models for beryllium exhibiting significantly different behavior when extrapolated to high strain. For beryllium, the α parameter of PTW has recently been calibrated to high precision shear modulus data. In the past the α value for beryllium was set based on expert judgment. The new α value for beryllium was used in a calibration of the beryllium PTW model by Sky Sjue. The calibration by Sjue used EOS table information to model the temperature dependence of the heat capacity. Also, the calibration by Sjue used EOS table information to model the density changes of the beryllium sample during the Hopkinson bar and quasi-static experiments. In this paper, the calibrated PTW model by Sjue is compared against experimental data and other strength models. The other strength models being considered are a PTW model calibrated by Shuh- Rong Chen and a Steinberg-Guinan type model by John Pedicini. The three strength models are used in a comparison against flyer plate and Taylor rod data. The results show that the Chen PTW model provides better agreement to this data. The Chen PTW model settings have been previously adjusted to provide a better fit to flyer plate data, whereas the Sjue PTW model has not been changed based on flyer plate data. However, the Sjue model provides a reasonable fit to

  8. Encyclopédie scientifique de l'universe: les étoiles - le système solaire.

    NASA Astrophysics Data System (ADS)

    This book is a revised, extended and updated edition of the volume published in 1979 (27.003.156).Contents: Première partie - le système solaire: 1. Astronomie des positions (J. Lévy). 2. Le système des constantes astronomiques; les données fondamentales (A. Bec-Borsenberger, F. Chollet). 3. Mécanique du système solaire (B. Morando). 4. Relief et structure des planètes telluriques et des satellites (A. Cazenave, P. Masson, P. Thomas). 5. Physique des atmosphères planétaires denses (D. Gautier, M. Combes,G. Moreels, J. P. Parisot, O. Tallagrand). 6. Les anneaux entourant les planètes (N. Borderies, A. Dollfus). 7. Les comètes et les météorites (A. Levasseur-Regourd). 8. L'environnement du Soleil et de la Terre (J.-L. Steinberg, J.-P. Bibring, A. Boischot, P. Couturier, R. Dumont, T. Encrenaz, P. Lamy).Deuxième partie - le Soleil et les bases de la physique stellaire: 9. Théorie des atmosphères du Soleil et des étoiles (R. Michard). 10. Physique de l'atmosphère solaire {non perturbée} (P. Mein). 11. Les centres actifs (J.-C. Hénoux, J.-C. Vial). 12. Éruptions solaires et phénomènes transitoires (J.-C. Hénoux, M. Pick, G. Trottet). 13. Le cycle solaire (J. Latour, P. Simon).Troisième partie - physique des étoiles: 14. Acquisition des données fondamentales (F. Spite). 15. Les étoiles doubles (R. Bouigue, P. Muller). 16. Les étoiles variables (M. Auvergne, A. Baglin, D. Ducatel, J.-M. Le Contel, J. C. Valtier). 17. Structure interne et évolution des étoiles (J.-P. Zahn). 18. Les familles physiques d'étoiles (G. Cayrel).

  9. Recent advances in data assimilation in computational geodynamic models

    NASA Astrophysics Data System (ADS)

    Ismail-Zadeh, Alik

    2010-05-01

    To restore dynamics of mantle structures in the geological past, data assimilation can be used to constrain the initial conditions for the mantle temperature and velocity from their present observations and estimations. The initial conditions so obtained can then be used to run forward models of mantle dynamics to restore the evolution of mantle structures. If heat diffusion is neglected, the present mantle temperature and flow can be assimilated using the backward advection (BAD) into the past. Two- and three-dimensional numerical approaches to the solution of the inverse problem of the Rayleigh-Taylor instability were developed for a dynamic restoration of diapiric structures to their earlier stages (e.g., Ismail-Zadeh et al., 1998, 2001, 2004; Kaus and Podladchikov, 2001). The mantle flow was modelled backwards in time from present-day mantle density heterogeneities inferred from seismic observations (e.g., Steinberger and O'Connell, 1998; Conrad and Gurnis, 2003). The variational (VAR) (or also called adjoint) data assimilation has been pioneered by meteorologists and widely used in oceanography and in hydrological studies. The use of VAR data assimilation in models of geodynamics has been put forward by Bunge et al. (2003) and Ismail-Zadeh et al. (2003). The VAR data assimilation algorithm was employed to restore numerically models of mantle plumes (Ismail-Zadeh et al., 2004, 2006; Hier-Majumder et al., 2005; Liu and Gurnis, 2008; Liu et al., 2008). The use of the quasi-reversibility (QRV) technique (more robust computationally) implies the introduction into the backward heat equation of the additional term involving the product of a small regularization parameter and a higher order temperature derivative (the resulting regularized heat equation is based on the Riemann law of heat conduction). The data assimilation in this case is based on a search of the best fit between the forecast model state and the observations by minimizing the regularization parameter

  10. The Messinian evaporites in the Levant Basin: lithology, deformation and its evolution

    NASA Astrophysics Data System (ADS)

    Feng, Ye; Steinberg, Josh; Reshef, Moshe

    2017-04-01

    . Feng, Y. E., & Reshef, M. (2016). The Eastern Mediterranean Messinian salt-depth imaging and velocity analysis considerations. Petroleum Geoscience, 22(4), 2-19. doi:http://dx.doi.org/10.1144/petgeo2015-088 Feng, Y. E., Yankelzon, A., Steinberg, J., & Reshef, M. (2016). Lithology and characteristics of the Messinian evaporite sequence of the deep Levant Basin, eastern Mediterranean. Marine Geology, 376, 118-131. doi:http://dx.doi.org/10.1016/j.margeo.2016.04.004

  11. Novel Sublingual Low-Dose Zolpidem Tablet Reduces Latency to Sleep Onset following Spontaneous Middle-of-the-Night Awakening in Insomnia in a Randomized, Double-Blind, Placebo-Controlled, Outpatient Study

    PubMed Central

    Roth, Thomas; Krystal, Andrew; Steinberg, Frank J.; Singh, Nikhilesh N.; Moline, Margaret

    2013-01-01

    : Clinical Trials Registration: NCT00466193: “A Study of Zolpidem Tartrate Tablet in Adult Patients with Insomnia” http://www.clinicaltrials.gov/ct2/show/NCT00466193?spons=%22Transcept+Pharmaceuticals%22&spons_ex=Y&rank=2 Citation: Roth T; Krystal A; Steinberg FJ; Singh NN; Moline M. Novel sublingual low-dose zolpidem tablet reduces latency to sleep onset following spontaneous middle-of-the-night awakening in insomnia in a randomized, double-blind, placebo-controlled, outpatient study. SLEEP 2013;36(2):189-196. PMID:23372266

  12. Test System Stability and Natural Variability of a Lemna Gibba L. Bioassay

    PubMed Central

    Scherr, Claudia; Simon, Meinhard; Spranger, Jörg; Baumgartner, Stephan

    2008-01-01

    Background In ecotoxicological and environmental studies Lemna spp. are used as test organisms due to their small size, rapid predominantly vegetative reproduction, easy handling and high sensitivity to various chemicals. However, there is not much information available concerning spatial and temporal stability of experimental set-ups used for Lemna bioassays, though this is essential for interpretation and reliability of results. We therefore investigated stability and natural variability of a Lemna gibba bioassay assessing area-related and frond number-related growth rates under controlled laboratory conditions over about one year. Methology/Principal Findings Lemna gibba L. was grown in beakers with Steinberg medium for one week. Area-related and frond number-related growth rates (r(area) and r(num)) were determined with a non-destructive image processing system. To assess inter-experimental stability, 35 independent experiments were performed with 10 beakers each in the course of one year. We observed changes in growth rates by a factor of two over time. These did not correlate well with temperature or relative humidity in the growth chamber. In order to assess intra-experimental stability, we analysed six systematic negative control experiments (nontoxicant tests) with 96 replicate beakers each. Evaluation showed that the chosen experimental set-up was stable and did not produce false positive results. The coefficient of variation was lower for r(area) (2.99%) than for r(num) (4.27%). Conclusions/Significance It is hypothesised that the variations in growth rates over time under controlled conditions are partly due to endogenic periodicities in Lemna gibba. The relevance of these variations for toxicity investigations should be investigated more closely. Area-related growth rate seems to be more precise as non-destructive calculation parameter than number-related growth rate. Furthermore, we propose two new validity criteria for Lemna gibba bioassays

  13. Global Dynamic Numerical Simulations of Plate Tectonic Reorganizations

    NASA Astrophysics Data System (ADS)

    Morra, G.; Quevedo, L.; Butterworth, N.; Matthews, K. J.; Müller, D.

    2010-12-01

    We use a new numerical approach for global geodynamics to investigate the origin of present global plate motion and to identify the causes of the last two global tectonic reorganizations occurred about 50 and 100 million years ago (Ma) [1]. While the 50 Ma event is the most well-known global plate-mantle event, expressed by the bend in the Hawaiian-Emperor volcanic chain, a prominent plate reorganization at about 100 Ma, although presently little studied, is clearly indicated by a major bend in the fracture zones in the Indian Ocean and by a change in Pacific plate motion [2]. Our workflow involves turning plate reconstructions into surface meshes that are subsequently employed as initial conditions for global Boundary Element numerical models. The tectonic setting that anticipates the reorganizations is processed with the software GPlates, combining the 3D mesh of the paleo-plate morphology and the reconstruction of paleo-subducted slabs, elaborated from tectonic history [3]. All our models involve the entire planetary system, are fully dynamic, have free surface, are characterized by a spectacular computational speed due to the simultaneous use of the multi-pole algorithm and the Boundary Element formulation and are limited only by the use of sharp material property variations [4]. We employ this new tool to unravel the causes of plate tectonic reorganizations, producing and comparing global plate motion with the reconstructed ones. References: [1] Torsvik, T., Müller, R.D., Van der Voo, R., Steinberger, B., and Gaina, C., 2008, Global Plate Motion Frames: Toward a unified model: Reviews in Geophysics, VOL. 46, RG3004, 44 PP., 2008 [2] Wessel, P. and Kroenke, L.W. Pacific absolute plate motion since 145 Ma: An assessment of the fixed hot spot hypothesis. Journal of Geophysical Research, Vol 113, B06101, 2008 [3] L. Quevedo, G. Morra, R. D. Mueller. Parallel Fast Multipole Boundary Element Method for Crustal Dynamics, Proceeding 9th World Congress and 4th Asian

  14. STAT3 governs hyporesponsiveness and granzyme B-dependent suppressive capacity in human CD4+ T cells

    PubMed Central

    Schmetterer, Klaus G.; Neunkirchner, Alina; Wojta-Stremayr, Daniela; Leitner, Judith; Steinberger, Peter; Pickl, Winfried F.

    2015-01-01

    Signal transducer and activator of transcription 3 (STAT3) integrates key signals of cell surface immune receptors, yet its precise role in cluster of differentiation (CD)4+ T cells is not well-established. Current research has indicated T-helper cell 17–inducing roles but also tolerogenic roles. To address this issue, human T cells were transduced with the constitutively active STAT3 mutant STAT3C. Following stimulation, STAT3C+ T cells up-regulated IL-10 (4.1 ± 0.5-fold; P < 0.001) and granzyme B (2.5 ± 1.2, P < 0.05) secretion, combined with significantly reduced IFN-γ (35 ± 5%), IL-2 (57 ± 4%), TNF-α (64 ± 8%), and IL-13 (89 ± 3%) secretion (P < 0.001). CD3/CD2- or CD3/CD28-activated STAT3C+ T cells revealed reduced proliferation (53.4 ± 23.5% and 70.5 ± 10.4%, respectively), which was independent of IL-10 production and significantly suppressed effector T cell proliferation by 68.7 ± 10.6% and 65.9 ± 2.6%, respectively (P < 0.001). Phenotypically, STAT3C-transgenic CD4+ T cells resembled effector T cells regarding expression of T regulatory cell markers, but up-regulated granzyme B expression levels by 2.4-fold (P < 0.05). Suppression was cell contact dependent and mediated by granzyme B-induced cell death, but was independent of IL-10 and TGF-β. Notably, peripheral blood CD4+CD45RA−lymphocyte activation gene-3+CD49+ type 1 regulatory T cells revealed activation-induced hyperphosphorylation of STAT3. In agreement, pharmacological inhibition of STAT3 activation partially reverted hyporesponsiveness of peripheral type 1 regulatory T cells (increasing their division index from 0.46 ± 0.11 to 0.89 ± 0.04; P < 0.01). These observations indicate a clear-cut relation between activation of STAT3 and the acquisition of a tolerogenic program, which is also used by peripheral blood type 1 regulatory T cells.—Schmetterer, K. G., Neunkirchner, A., Wojta-Stremayr, D., Leitner, J., Steinberger, P., Pickl, W. F. STAT3 governs hyporesponsiveness and

  15. Optical signal processing of phased array radar

    NASA Astrophysics Data System (ADS)

    Weverka, Robert T.

    this analysis technique. This Bragg cell provides a low insertion delay making it suitable for the feedback phased array radar systems. This thesis develops a new algorithm for phased array radar processing. This adaptation of the Widrow algorithm requires fewer delay lines allowing us to implement a system that can scale to dense two-dimensional phased array radar. The thesis explores this processor in depth, developing the description of the system evolution, the nonlinear dynamics governing the system and the dynamic range: that can be achieved. The system behavior and dynamics are confirmed experimentally. Finally this thesis explores positive feed back architectures for the phased radar problem posed by Steinberg in which the array itself is poorly surveyed. To our knowledge, optical signal processing solutions to this problem have not been developed prior to this work.

  16. Polyphase basin evolution of the Vienna Basin inferred from 3D visualization of sedimentation setting and quantitative subsidence

    NASA Astrophysics Data System (ADS)

    Lee, Eun Young; Novotny, Johannes; Wagreich, Michael

    2016-04-01

    This study analyzed and visualized data from 210 wells using a MATLAB-based program (BasinVis 1.0) for 3D visualization of sediment distribution, thickness, and quantitative subsidence of the northern and central Vienna Basin. The sedimentation settings for selected horizons were visualized to 3D sediment distribution maps, isopach maps, and cross-sections. Subsidence of the study area resulted in 3D subsidence depth and rate maps of basement and tectonic subsidences. Due to the special position of the Vienna Basin, the basin evolution was influenced by the regional tectonics of surrounding units. The 2D/3D maps provided insights into the polyphase evolution of the Vienna Basin, which is closely related to changes in the changing regional stress field and the paleoenvironmental setting. In the Early Miocene, the sedimentation and subsidence were shallow and E-W/NE-SW trending, indicating the development of piggy-back basins. During the late Early Miocene, maps show wider sedimentation and abruptly increasing subsidence by sinistral strike-slip faults, which initiated the Vienna pull-apart basin system. The sediments of the Early Miocene were supplied through a small deltaic system entering from the south. After thin sedimentation and shallow subsidence of the early Middle Miocene, the development of the Vienna Basin was controlled and accelerated mainly by NE-SW trending synsedimentary normal faults, especially the Steinberg fault. From the Middle Miocene, the subsidence was decreasing overall, however the tectonic subsidence show regionally different patterns. This study suggests that a major tensional regime change, from transtension to E-W extension, caused laterally varying subsidence across the Vienna Basin. The Late Miocene was characterized by the slowing down of basement and tectonic subsidence. From the middle Middle to Late Miocene, enormous amount of sediments supplied by a broad paleo-Danube delta complex on the western flank of the basin. The latest

  17. [End-of-life decision-making process].

    PubMed

    Steinberg, Avraham

    2003-10-01

    Since time immemorial the attitude toward the dying patient has been one of the most difficult issues in medical ethics. The diversity of philosophical, religious, social and legal approaches does not enable one to reach a universal consensus to solve the many problems involved in end-of-life decisions. Within the health care system in Israel there is currently no consensual practice concerning the dying patient. Moreover, there is no published information on the actual decision-making processes within hospitals, hospices and geriatric facilities in Israel concerning the dying patient. A group of investigators in Shaare Zedek Medical Center in Jerusalem recently performed a prospective study to explore the decision-making process concerning DNR orders within this hospital. The results of this study demonstrated that the terminally-ill patients never take part in the decision-making process, they are never consulted about their wishes, and there is no effort to discover their previous wishes concerning their treatment at the terminal stages. Moreover, in many instances even the family was not consulted and did not take part in the decision-making process. In a significant minority, the final decision of a DNR order was undertaken by a single physician. This approach represents an extreme form of unethical paternalism, and it requires an urgent societal intervention to establish an ethically sound decision-making process. Recently, a national committee ("Steinberg Committee") formulated a widely agreed upon legislative proposal organizing all the fundamental and practical issues related to the dying patient. This proposal is based upon a balance between opposing values such as autonomy, life, quality-of-life, beneficence, non-maleficence and "slippery-slope" concerns. It relates to various treatment modalities, such as resuscitation, ventilation, dialysis, medication and sustenance. It establishes a clear position on euthanasia, physician-assisted suicide

  18. Analysis and suppression of instabilities in viscoelastic flows

    NASA Astrophysics Data System (ADS)

    Kumar, Karkala Arun

    2001-10-01

    The viscoelastic character of polymer solutions and melts gives rise to instabilities not seen in the flows of Newtonian liquids. In this thesis, we computationally study four such instabilities. The first instability we discuss is melt fracture, which takes the form of gross distortions of the polymer surface during extrusion. This instability is linked to multiplicity in the slip curve. We show here that when the dependence of slip velocity on pressure is taken into account, multiplicity in the slip law does not necessarily imply a multi-valued flow curve or melt fracture. Next, we study the ``filament-stretching'' instability, which takes the form of non-axisymmetric deviations of the free surface of a polymeric liquid bridge being extended between two parallel plates. We model the portion of the filament near the endplates as an elastic membrane enclosing an incompressible fluid and show that this is unstable to non-axisymmetric disturbances. The third instability we discuss is the purely elastic instability in Dean flow. This instability is linked to elastic instabilities in more complicated and industrially important coating flows with curved streamlines. We show how the addition of a small secondary axial flow in a steady or periodic fashion can significantly delay the onset of the instability. Recent experimental observations by Groisman and Steinberg ( Phys. Rev. Lett. 78(8), 1460-1463, 1997) and Baumert and Muller (Phys. Fluids, 9(3), 566-586, 1999) have shown the formation of spatially isolated, stationary, axisymmetric patterns in the nonlinear regime of circular Couette flow, termed ``diwhirls'' or ``flame patterns.'' Modeling these patterns is complicated by the absence of a stationary bifurcation in isothermal circular Couette flow. We show here how these solutions may be accessed by numerical continuation from stationary bifurcations in Couette-Dean flows. Although the solutions we compute are unstable, they show qualitative and quantitative

  19. Constraints on the mantle and lithosphere dynamics from the observed geoid with the effect of visco-elasto-plastic rheology in the upper 300 km

    NASA Astrophysics Data System (ADS)

    Osei Tutu, Anthony; Steinberger, Bernhard; Rogozhina, Irina; Sobolev, Stephan

    2015-04-01

    used. Finally, given significant dispersion of geodynamic predictions from different seismic tomography models currently available, we further look for seismic models that provide predictions closest to observations at both regional and global scales. References 1. Hager B.H & O'Connell R.J., 1981. A simple global model of plate dynamics and mantle convection, J.Geophys. Res. 86, 4843-4867 2. Popov A.A., Sobolev S.V., 2008. SLIM3D: A tool for three-dimensional thermo- mechanical modelling of lithospheric deformation with elasto-visco-plastic rheology, J.pepi.2008.03.007 3. Steinberger B., 2014. Dynamic topography: A comparison between observations and models based on seismic tomography. (Submitted) 4. Becker T and Boschi L., 2002, A comparison of tomographic and geodynamic mantle models. , J.Geophys. Res. 115, 0148-0227

  20. Diffusion-enhanced Förster resonance energy transfer and the effects of external quenchers and the donor quantum yield.

    PubMed

    Jacob, Maik H; Dsouza, Roy N; Ghosh, Indrajit; Norouzy, Amir; Schwarzlose, Thomas; Nau, Werner M

    2013-01-10

    The structural and dynamic properties of a flexible peptidic chain codetermine its biological activity. These properties are imprinted in intrachain site-to-site distances as well as in diffusion coefficients of mutual site-to-site motion. Both distance distribution and diffusion determine the extent of Förster resonance energy transfer (FRET) between two chain sites labeled with a FRET donor and acceptor. Both could be obtained from time-resolved FRET measurements if their individual contributions to the FRET efficiency could be systematically varied. Because the FRET diffusion enhancement (FDE) depends on the donor-fluorescence lifetime, it has been proposed that the FDE can be reduced by shortening the donor lifetime through an external quencher. Benefiting from the high diffusion sensitivity of short-distance FRET, we tested this concept experimentally on a (Gly-Ser)(6) segment labeled with the donor/acceptor pair naphthylalanine/2,3-diazabicyclo[2.2.2]oct-2-ene (NAla/Dbo). Surprisingly, the very effective quencher potassium iodide (KI) had no effect at all on the average donor-acceptor distance, although the donor lifetime was shortened from ca. 36 ns in the absence of KI to ca. 3 ns in the presence of 30 mM KI. We show that the proposed approach had to fail because it is not the experimentally observed but the radiative donor lifetime that controls the FDE. Because of that, any FRET ensemble measurement can easily underestimate diffusion and might be misleading even if it employs the Haas-Steinberg diffusion equation (HSE). An extension of traditional FRET analysis allowed us to evaluate HSE simulations and to corroborate as well as generalize the experimental results. We demonstrate that diffusion-enhanced FRET depends on the radiative donor lifetime as it depends on the diffusion coefficient, a useful symmetry that can directly be applied to distinguish dynamic and structural effects of viscous cosolvents on the polymer chain. We demonstrate that the

  1. Nazca absolute plate motion and Pacific basin inter-hotspot motion

    NASA Astrophysics Data System (ADS)

    Harada, Y.; Wessel, P.; Naar, D.; Wilder, D.; Duncan, R. A.; Mahoney, J. J.; Johnson, K. T.; Pyle, D. G.; Ray, J. S.

    2003-04-01

    Historically, hotspots have been used to define a fixed reference frame for plate motions: however, since hotspots are rooted within a dynamically convecting mantle, it is hard to believe that the fixity is absolute and instead slow motion between hotspots are expected to be occurring. Thus "how slow" is the central issue that needs to be addressed. Harada and Hamano (2000) and Harada and Wessel (2003, in prep.) showed that the mean speed since 70Ma for inter-hotspot motion within the Pacific plate is less than 4 or 5 mm per year. Recently, Steinberger (2002) suggested a numerical model for westward motion of the Easter hotspot at several cm per year relative to the Hawaii and Louisville hotspots. To test his hypothesis we dredged more than 70 sites along the Nazca Ridge and Easter Seamount Chain during the Drift expedition, Leg 6, of the R/V Revelle and dated more than 20 samples using the Ar/Ar method to examine the motion of the Easter hotspot relative to the Pacific hotspots. To estimate the positions and ages of the Easter hotspot track on the Nazca plate, we needed a good model of the absolute motion of the Nazca plate (Nazca APM) and present location of the Easter hotspot. For the modeling of the Nazca APM, we combined several existing models of Pacific APM with Pacific-Nazca relative motions (Pac-Naz RPM) determined from magnetic anomalies, and investigated the differences of these Nazca APM models. To determine the present location of the Easter hotspot, we applied the hot-spotting technique (Wessel and Kroenke, 1997) using the Nazca APM models, and then examined the differences in the optimal CVA locations. Because the hot-spotting technique can predict the present position of a hotspot without using any age data, we could test the modeled ages of the theoretical hotspot track by comparing them with observed ages of the hotspot track. The present position of the Easter hotspot is found to be near Salas y Gomez Island, not Easter Island. Although there are

  2. Global Paleobathymetry for the Cenomanian-Turonian (90 Ma)

    NASA Astrophysics Data System (ADS)

    Goswami, A.; Olson, P.; Hinnov, L. A.; Gnanadesikan, A.

    2014-12-01

    , C., Steinberger, B., Heine, C., 2008a, Science, 319, 1357-1362. Scotese, C., 2011, PALEOMAP Project, Arlington, Texas. Turcotte, D., Schubert, G., 2002, Cambridge University Press, Cambridge, 456 p. Whittaker, J., Goncharov, A., Williams, S., Müller, R., Leitchenkov, G., 2013, Geochemistry, Geophysics, Geosystems. DOI:10.1002/ggge.20181

  3. Examining the effects of students' classroom expectations on undergraduate biology course reform

    NASA Astrophysics Data System (ADS)

    Hall, Kristi Lyn

    In this dissertation, I perform and compare three studies of introductory biology students' classroom expectations -- what students expect to be the nature of the knowledge that they are learning, what they think they should be (or are) doing in order to learn, and what they think they should be (or are) doing in order to be successful. Previous work has shown that expectations can impact how students approach learning, yet biology education researchers have been reluctant to acknowledge or address the effects of student expectations on curricular reform (NRC, 2012). Most research in biology education reform has focused on students' conceptual understandings of biology and the efficacy of specific changes to content and pedagogy. The current research is lacking a deeper understanding of how students perceive the classroom environment and how those perceptions can shape students' interactions with the content and pedagogy. For present and future reforms in biology to reach their full potential, I argue that biology education should actively address the different ways students think about and approach learning in biology classes. The first study uses a Likert-scale instrument, adapted from the Maryland Physics Expectations Survey (Redish, Saul, & Steinberg, 1998). This new survey, the Maryland Biology Expectations Survey (MBEX) documents two critical results in biology classrooms: (i) certain student-centered pedagogical contexts can produce favorable changes in students' expectations, and (ii) more traditional classroom contexts appear to produce negative epistemological effects. The second study utilizes a modified version of the MBEX and focuses on students' interdisciplinary views. This study documents that: (i) biology students have both discipline-specific and context-specific classroom expectations, (ii) students respond more favorably to interdisciplinary content in the biology courses we surveyed (as opposed to biology content introduced into the physics

  4. Designing across ages: Multi-agent-based models and learning electricity

    NASA Astrophysics Data System (ADS)

    Sengupta, Pratim

    Electricity is regarded as one of the most challenging topics for students at all levels -- middle school -- college (Cohen, Eylon, & Ganiel, 1983; Belcher & Olbert, 2003; Eylon & Ganiel, 1990; Steinberg et al., 1985). Several researchers have suggested that naive misconceptions about electricity stem from a deep incommensurability (Slotta & Chi, 2006; Chi, 2005) or incompatibility (Chi, Slotta & Leauw, 1994; Reiner, Slotta, Chi, & Resnick, 2000) between naive and expert knowledge structures. I first present an alternative theoretical framework that adopts an emergent levels-based perspective as proposed by Wilensky & Resnick (1999). From this perspective, macro-level phenomena such as electric current and resistance, as well as behavior of linear electric circuits, can be conceived of as emergent from simple, body-syntonic interactions between electrons and ions in a circuit. I argue that adopting such a perspective enables us to reconceive commonly noted misconceptions in electricity as behavioral evidences of "slippage between levels" -- i.e., these misconceptions appear when otherwise productive knowledge elements are sometimes inappropriately activated due to certain macro-level phenomenological cues only -- and, that the same knowledge elements when activated due to phenomenological cues at both micro- and macro-levels, can engender a deeper, expert-like understanding. I will then introduce NIELS (NetLogo Investigations In Electromagnetism, Sengupta & Wilensky, 2006, 2008, 2009), a low-threshold high-ceiling (LTHC) learning environment of multi-agent-based computational models that represent phenomena such as electric current and resistance, as well as the behavior of linear electric circuits, as emergent. I also present results from implementations of NIELS in 5th, 7th and 12th grade classrooms that show the following: (a) how leveraging certain "design elements" over others in NIELS models can create new phenomenological cues, which in turn can be

  5. Biomimetic Production of Hydrogen

    NASA Astrophysics Data System (ADS)

    Gust, Devens

    2004-03-01

    organism. Some possible approaches to achieving this will be discussed. References (1) Gust, D.; Moore, T. A.; Moore, A. L. "Mimicking photosynthetic solar energy transduction," Acc. Chem. Res. 2001, 34, 40-48. (2) Kodis, G.; Liddell, P. A.; de la Garza, L.; Clausen, P. C.; Lindsey, J. S.; Moore, A. L.; Moore, T. A.; Gust, D. "Efficient energy transfer and electron transfer in an artificial photosynthetic antenna-reaction center complex," J. Phys. Chem. A 2002, 106, 2036-2048. (3) Liddell, P. A.; Kuciauskas, D.; Sumida, J. P.; Nash, B.; Nguyen, D.; Moore, A. L.; Moore, T. A.; Gust, D. "Photoinduced charge separation and charge recombination to a triplet state in a carotene-porphyrin-fullerene triad," J. Am. Chem. Soc. 1997, 119, 1400-1405. (4) Steinberg-Yfrach, G.; Liddell, P. A.; Hung, S.-C.; Moore, A. L.; Gust, D.; Moore, T. A. "Artificial photosynthetic reaction centers in liposomes: Photochemical generation of transmembrane proton potential," Nature 1997, 385, 239-241. (5) Steinberg-Yfrach, G.; Rigaud, J.-L.; Durantini, E. N.; Moore, A. L.; Gust, D.; Moore, T. A. "Light-driven production of ATP catalyzed by F0F1-ATP synthase in an artificial photosynthetic membrane," Nature 1998, 392, 479-482. (6) de la Garza, L.; Jeong, G.; Liddell, P. A.; Sotomura, T.; Moore, T. A.; Moore, A. L.; Gust, D. "Enzyme-based photoelectrochemical biofuel cell," J. Phys. Chem. B 2003, 107, 10252-10260.

  6. Mechanism and Significance of Post-Translational Modifications in the Large (LS) and Small (SS) Subunits of Ribulose-1,5 Bisphosphate Carboxylase/Oxygenase

    SciTech Connect

    Houtz, Robert, L.

    2012-11-09

    . Additionally, the tight initial binding of Rubisco LSMT to Rubisco also allowed us to design a novel immobilized complex between Rubisco and Rubisco LSMT, which allowed for an unambiguous demonstration of the requirement for trimethyllysine formation prior to disassociation of the Rubisco LSMT:Rubisco complex, and therefore proof of the processive mechanism for methyl group transfer. These kinetic studies also demonstrated that an important factor has been overlooked in all kinetic analyses of SET domain protein methyltransferases reported to date. This factor is the influence of the low turnover number for SET domain protein methyltransferases and how, relative to the time-frame of kinetic enzyme assays, this can generate changes in kinetic profiles shifting reciprocal plot patterns from random/ordered bi-bi to the real kinetic reaction mechanism plots of ping-pong. Although the ternary complexes of Rubisco LSMT with S-Adenosylhomocysteine and lysine and monomethyllysine were informative in regard to reaction mechanism, they were not helpful in identifying the mechanism used by Rubisco LSMT for determining substrate specificity. We were unsuccessful at obtaining ternary complexes of Rubisco LSMT with bound synthetic polypeptide substrates, as has been reported for several histone methyltransferases. However, we were able to model a polypeptide sequence corresponding to the N-terminal region of the LS of Rubisco into the apparent substrate binding cleft in Rubisco LSMT. Knowledge of the determinants of polypeptide substrate specificity are important for identifying possible alternate substrates, as well as the possibility of generating more desirable substrates amenable to site-directed mutagenesis experiments unlike Rubisco. We determined that Rubisco LSMT is capable of methylating synthetic polypeptide mimics of the N-terminal region of the LS, both free as well as conjugated to keyhole limpet hemacyanin, but with considerable less efficiency than intact holoenzyme.

  7. Feasibility of using benthic invertebrates as indicators of stream quality in Hawaii

    USGS Publications Warehouse

    Wolff, Reuben H.

    2005-01-01

    Macroinvertebrates were collected from 19 sites on 14 streams on the island of Oahu and from 9 sites on 7 streams on the island of Kauai to evaluate associations between macroinvertebrate assemblages and environmental variables and to determine whether or not it would be feasible, in future studies, to develop macroinvertebrate metrics that would indicate stream quality based on the macroinvertebrate assemblages and/or components of the assemblages. The purpose of applying rapid bioassessment techniques is to identify stream quality problems and to document changes in stream quality. Samples were collected at 10 sites in 1999, 3 sites in 2000, and 5 sites in 2003 on Oahu and at 9 sites on Kauai in 2003. Additionally, multiple year and multiple reach samples were collected at 1 site on Oahu. Macroinvertebrates were collected primarily from boulder/cobble riffles or from the fastest flowing habitat when riffles were absent. Although most streams in Hawaii originate in mountainous, forested areas, the lower reaches often drain urban, agricultural, or mixed land-use areas. The macroinvertebrate community data were used to identify metrics that could best differentiate between sites according to levels of environmental impairment. Environmental assessments were conducted using land-use/land-cover data, bed-sediment and fish-tissue contaminant data, and reach-level environmental data using a calibration set of 15 sites. The final scores of the environmental assessments were used to classify the sites into three categories of impairment: mild, moderate or severe. A number of invertebrate metrics were then tested and calibrated to the environmental assessments scores. The individual metrics that were the best at discerning environmental assessments among the sites were combined into a multimetric benthic index of biotic integrity (BIBI). These metrics were: total invertebrate abundance, taxa richness, insect relative abundance, amphipod abundance, crayfish presence or

  8. The geological evolution of Merapi volcano, Central Java, Indonesia

    NASA Astrophysics Data System (ADS)

    Gertisser, Ralf; Charbonnier, Sylvain J.; Keller, Jörg; Quidelleur, Xavier

    2012-07-01

    Merapi is an almost persistently active basalt to basaltic andesite volcanic complex in Central Java (Indonesia) and often referred to as the type volcano for small-volume pyroclastic flows generated by gravitational lava dome failures (Merapi-type nuées ardentes). Stratigraphic field data, published and new radiocarbon ages in conjunction with a new set of 40K-40Ar and 40Ar-39Ar ages, and whole-rock geochemical data allow a reassessment of the geological and geochemical evolution of the volcanic complex. An adapted version of the published geological map of Merapi [(Wirakusumah et al. 1989), Peta Geologi Gunungapi Merapi, Jawa Tengah (Geologic map of Merapi volcano, Central Java), 1:50,000] is presented, in which eight main volcano stratigraphic units are distinguished, linked to three main evolutionary stages of the volcanic complex—Proto-Merapi, Old Merapi and New Merapi. Construction of the Merapi volcanic complex began after 170 ka. The two earliest (Proto-Merapi) volcanic edifices, Gunung Bibi (109 ± 60 ka), a small basaltic andesite volcanic structure on Merapi's north-east flank, and Gunung Turgo and Gunung Plawangan (138 ± 3 ka; 135 ± 3 ka), two basaltic hills in the southern sector of the volcano, predate the Merapi cone sensu stricto. Old Merapi started to grow at ~30 ka, building a stratovolcano of basaltic andesite lavas and intercalated pyroclastic rocks. This older Merapi edifice was destroyed by one or, possibly, several flank failures, the latest of which occurred after 4.8 ± 1.5 ka and marks the end of the Old Merapi stage. The construction of the recent Merapi cone (New Merapi) began afterwards. Mostly basaltic andesite pyroclastic and epiclastic deposits of both Old and New Merapi (<11,792 ± 90 14C years BP) cover the lower flanks of the edifice. A shift from medium-K to high-K character of the eruptive products occurred at ~1,900 14C years BP, with all younger products having high-K affinity. The radiocarbon record points towards an

  9. In situ measurement of mesopelagic particle sinking rates and the control of carbon transfer to the ocean interior during the Vertical Flux in the Global Ocean (VERTIGO) voyages in the North Pacific

    NASA Astrophysics Data System (ADS)

    Trull, T. W.; Bray, S. G.; Buesseler, K. O.; Lamborg, C. H.; Manganini, S.; Moy, C.; Valdes, J.

    2008-07-01

    sinking slower than 137 m d -1. At K2, less than 1% of the POC flux sank at >820 m d -1, but a large fraction (˜15-45%) of the flux was contributed by other fast-sinking classes (410 and 205 m d -1). PIC and BSi minerals were not present in higher proportions in the faster sinking fractions, but the observations were too limited to rule out a ballasting contribution to the control of sinking rates. Photographic evidence for a wide range of particle types within individual sinking-rate fractions suggests that biological processes that set the porosity and shape of particles are also important and may mask the role of minerals. Comparing the spectrum of sinking rates observed at K2 with the power-law profile of flux attenuation with depth obtained from other VERTIGO sediment traps deployed at multiple depths [Buesseler, K.O., Lamborg, C.H., Boyd, P.W., Lam, P.J., Trull, T.W., Bidigare, R.R., Bishop, J.K.B., Casciotti, K.L., Dehairs, F., Elskens, M., Honda, M., Karl, D.M., Siegel, D., Silver, M., Steinberg, D., Valdes, J., Van Mooy, B., Wilson, S.E., 2007b. Revisiting carbon flux through the Ocean's twilight zone. Science 316(5824), 567-570, doi: 10.1126/science.1137959] emphasizes the importance of particle transformations within the mesopelagic zone in the control of carbon transport to the ocean interior.

  10. Silicate melt metasomatism in the lithospheric mantle beneath SW Poland

    NASA Astrophysics Data System (ADS)

    Puziewicz, Jacek; Matusiak-Małek, Magdalena; Ntaflos, Theodoros; Grégoire, Michel; Kukuła, Anna

    2014-05-01

    The xenoliths of peridotites representing the subcontinental lithospheric mantle (SCLM) beneath SW Poland and adjacent parts of Germany occur in the Cenozoic alkaline volcanic rocks. Our study is based on detailed characterization of xenoliths occurring in 7 locations (Steinberg in Upper Lusatia, Księginki, Pilchowice, Krzeniów, Wilcza Góra, Winna Góra and Lutynia in Lower Silesia). One of the two major lithologies occurring in the xenoliths, which we call the "B" lithology, comprises peridotites (typically harzburgites) with olivine containing from 90.5 to 84.0 mole % of forsterite. The harzburgites contain no clinopyroxene or are poor in that mineral (eg. in Krzeniów the group "B" harzburgites contain < 1 vol. % of the mineral). They exhibit significant variation in orthopyroxene contents, which varies from 25 to 10 vol. %. Some of the xenoliths are more impoverished in orthopyroxene and have dunitic compositions. The ortho- and clinopyroxene exhibit mg# similar to that of olivine, and typically are low aluminous (Al < 0.10 atom pfu in ortho-, and < 0.20 atom pfu in clinopyroxene). The exception are xenoliths from Księginki, which contain pyroxenes characterised by negative correlation between mg# and Al. The REE patterns of both ortho- and clinopyroxene in the group "B" peridotites suggest equilibration with silicate melt. The rocks of "B" lithology were formed due to alkaline silicate melt percolation in the depleted peridotitic protolith. The basaltic melts formed at high pressure are usually undersaturated in both ortho- and clinopyroxene at lower pressures (Kelemen et al. 1992). Because of cooling and dissolution of ortho- and clinopyroxene the melts change their composition and become saturated in one or both of those phases. Experimental results (e.g. Tursack & Liang 2012 and references therein) show that the same refers to alkaline basaltic silicate melts and that its reactive percolation in the peridotitic host leads to decrease of Mg

  11. The Solid Earth Research and Teaching Environment, a new software framework to share research tools in the classroom and across disciplines

    NASA Astrophysics Data System (ADS)

    Milner, K.; Becker, T. W.; Boschi, L.; Sain, J.; Schorlemmer, D.; Waterhouse, H.

    2009-12-01

    The Solid Earth Teaching and Research Environment (SEATREE) is a modular and user-friendly software framework to facilitate the use of solid Earth research tools in the classroom and for interdisciplinary research collaboration. SEATREE is open source and community developed, distributed freely under the GNU General Public License. It is a fully contained package that lets users operate in a graphical mode, while giving more advanced users the opportunity to view and modify the source code. Top level graphical user interfaces which initiate the calculations and visualize results, are written in the Python programming language using an object-oriented, modern design. Results are plotted with either Matlab-like Python libraries, or SEATREE’s own Generic Mapping Tools wrapper. The underlying computational codes used to produce the results can be written in any programming language and accessed through Python wrappers. There are currently four fully developed science modules for SEATREE: (1) HC is a global geodynamics tool based on a semi-analytical mantle-circulation program based on work by B. Steinberger, Becker, and C. O'Neill. HC can compute velocities and tractions for global, spherical Stokes flow and radial viscosity variations. HC is fast enough to be used for classroom instruction, for example to let students interactively explore the role of radial viscosity variations for global geopotential (geoid) anomalies. (2) ConMan wraps Scott King’s 2D finite element mantle convection code, allowing users to quickly observe how modifications to input parameters affect heat flow over time. As seismology modules, SEATREE includes, (3), Larry, a global, surface wave phase-velocity inversion tool and, (4), Syn2D, a Cartesian tomography teaching tool for ray-theory wave propagation in synthetic, arbitrary velocity structure in the presence of noise. Both underlying programs were contributed by Boschi. Using Syn2D, students can explore, for example, how well a given

  12. Regional subsidence history and 3D visualization with MATLAB of the Vienna Basin, central Europe

    NASA Astrophysics Data System (ADS)

    Lee, E.; Novotny, J.; Wagreich, M.

    2013-12-01

    Group C decreases gradually, which demonstrates a trend of increasing thermal subsidence during the Middle to Upper Miocene. The traditional model cannot explain the thermal subsidence observed in the central part. This study supports a non-uniform extension model changing from the thin-skinned extension in the northern part to the thick-skinned extension in the central part. And 3D subsidence maps propose the existence of a decoupling between lithospheric and crustal extensions along the Steinberg Fault. Group L shows very different subsidence trends compared to Group C and N. In this Group a subsidence halt occurred in the late Lower Miocene. After the halt, Group L1 shows small tectonic and subsidence events. Some former studies presented that the area of Group L1 uplifted during the early Middle Miocene. It can be concluded that the missing sediments were eroded by the local uplift. But the subsidence of Group L2 stopped completely. It suggests that Group L2 was not influenced by the extension of the strike-slip fault system.

  13. The Paris Observatory has 350 years

    NASA Astrophysics Data System (ADS)

    Lequeux, James

    2017-01-01

    1926, the astrophysical observatory at Meudon was merged with the Paris one. A strong revival of the Observatory and of all French astronomy took place just after WW2 under the impulse of André Danjon. Radioastronomy was developed with the creation of the Nançay station in 1953, and the Observatory became very active in space research after 1963 thanks mainly to Jean-Louis Steinberg. It is presently one of the biggest astronomical institutes worldwide, with a total scientific, technical and administrative staff of 650, and many students and post-doctoral researchers. Essentially all the aspects of astronomy and astrophysics are covered, including laboratory work, especially on very accurate clocks. However, essentially all the observations are done elsewhere, particularly in international facilities such as IRAM, ESO and with many satellites and space probes.

  14. A Short Review of True Polar Wander

    NASA Astrophysics Data System (ADS)

    Courtillot, V.

    2004-12-01

    -discontinuous 90° rotation is possible in which the rotation axis will align with a new axis of maximum non-hydrostatic moment of inertia (inertial interchange event IITPW). Oscillatory polar wander is thought by some to be documented in the Precambrian, which is attributed to TPW about a long-lived inertial axis inherited from the super-continent of Rodinia (Evans). Modeling of TPW has made significant progress. Seismic tomography is used to infer 3D maps of density heterogeneities that drive flow in the viscous mantle. The maximum speed of polar wander driven by mantle convection is about 100km/m.y. A significant viscosity increase in the lower mantle is required to bring TPW rates closer to observed values. Recent modeling (Steinberger) involves limited, predictable inter-hotpot motion. One can still derive a TPW curve in the "mean mantle" reference frame that takes hotspot motions into account. This captures most of the features of the observed TPW. Possible links between 1) TPW episodes, or major changes between TPW episodes, or IITPW events, 2) reorganizations in the geometry of subduction zones (e.g. avalanches), or plume and superplume generation, and 3) major biotic changes (e.g. mass extinctions) will likely keep analyses of polar wander very much alive in the coming decade, despite the somewhat bothering feeling that true polar wander still remains an elusive geophysical phenomenon.

  15. RHUM-RUM investigates La Réunion mantle plume from crust to core

    NASA Astrophysics Data System (ADS)

    Sigloch, Karin; Barruol, Guilhem

    2013-04-01

    neighboring ridges of the Indian Ocean. There is in particular a long-standing hypothesis, not yet examined seismically, that channelized plume flow beneath the aseismic Rodrigues Ridge could feed the Central Indian Ridge at 1000 km distance. The RHUM-RUM group (www.rhum-rum.net): * IPG Paris & Géosciences Réunion: G. Barruol, J.P. Montagner, E. Stutzmann, F.R. Fontaine, C. Deplus, M. Cannat, G. Roult, J. Dyment, S. Singh, W. Crawford, C. Farnetani, N. Villeneuve, L. Michon. V. Ferrazzini, Y. Capdeville. * Univ. Munich (LMU): K. Sigloch, H. Igel. AWI Bremerhaven: V. Schlindwein. Univ. Frankfurt: G. Rümpker. Univ. Münster: C. Thomas. Univ. Bonn: S. Miller. * Géosciences Montpellier: C. Tiberi, A. Tommasi, D. Arcay, C. Thoraval. * Mauritius Oceanography Institute: D. Bissessur. Univ. Antananarivo: G. Rambolamanana. SEYPEC Seychelles Petroleum: P. Samson, P. Joseph. * Other institutes: A. Davaille, M. Jegen, M. Maia, G. Nolet, D. Sauter, B. Steinberger.

  16. RHUM-RUM investigates La Réunion mantle plume from crust to core

    NASA Astrophysics Data System (ADS)

    Sigloch, K.; Barruol, G.

    2012-12-01

    neighboring ridges of the Indian Ocean. There is in particular a long-standing hypothesis, not yet examined seismically, that channelized plume flow beneath the aseismic Rodrigues Ridge could feed the Central Indian Ridge at 1000 km distance. The RHUM-RUM group (www.rhum-rum.net): * IPG Paris & Géosciences Réunion: G. Barruol, J.P. Montagner, E. Stutzmann, F.R. Fontaine, C. Deplus, M. Cannat, G. Roult, J. Dyment, S. Singh, W. Crawford, C. Farnetani, N. Villeneuve, L. Michon. V. Ferrazzini, Y. Capdeville. * Univ. Munich (LMU): K. Sigloch, H. Igel. AWI Bremerhaven: V. Schlindwein. Univ. Frankfurt: G. Rümpker. Univ. Münster: C. Thomas. Univ. Bonn: S. Miller. * Géosciences Montpellier: C. Tiberi, A. Tommasi, D. Arcay, C. Thoraval. * Mauritius Oceanography Institute: D. Bissessur. Univ. Antananarivo: G. Rambolamanana. SEYPEC Seychelles Petroleum: P. Samson, P. Joseph. * Other institutes: A. Davaille, M. Jegen, M. Maia, G. Nolet, D. Sauter, B. Steinberger.

  17. A new phase of matter in Oakland

    SciTech Connect

    Klein, Spencer; Nystrand, Joakim

    2004-03-18

    Recent results from the Relativistic Heavy Ion Collider (RHIC) and the phase diagram of matter at very high energies were the focal points of Quark Matter 2004, held January 10-17, 2004 in the Oakland, California convention center. About 700 participants, including 125 students, from 28 countries gathered for 5 days of plenary and parallel sessions. Besides the scientific discussions, participants enjoyed an afternoon of excursions; choices included visits to San Francisco, the Muir woods, and, of course, a chance to sample Napa Valley wines. There was also a day of introductory lectures for graduate students and a separate afternoon program for 50 local high school teachers. The ''Quark Matter'' conference series has evolved into the premier venue for relativistic heavy ion collisions, and QM2004 was no exception. The 44 plenary and 92 parallel session talks featured a veritable flood of data from STAR (Kai Schweda, LBNL), PHENIX (Tony Frawley, Florida State), PHOBOS (Peter Steinberg, BNL) and BRAHMS (Michael Murray, Kansas), at RHIC. This was accompanied by contributions from HERMES ( Pasquale DiNezza, Frascati) and HERA-B (Joakim Spengler, Heidelberg) and continuing analyses from NA-49 (Marek Gazdzicki, Frankfurt) and NA-57 (Giuseppe Bruno, Bari) at the CERN SPS. The theoretical contributions presented a broad range of models and calculations, from microscopic particle-by-particle simulations to hydrodynamic models that model the bulk behavior using an equation of state. A focus of much discussion was the question ''Have we found the Quark Gluon Plasma (QGP)?'' This search was the prime motivation to build RHIC. Although the RHIC experiments made no formal statement, most conference attendees seemed to feel that the answer was yes. No single measurement makes the case, but the variety of data featured at QM2004 seems most easily explained in the context of a QGP. Some of the signatures included the suppression of high transverse momentum (pT) particles and

  18. Pions to Quarks

    NASA Astrophysics Data System (ADS)

    Brown, Laurie Mark; Dresden, Max; Hoddeson, Lillian

    2009-01-01

    Part I. Introduction; 1. Pions to quarks: particle physics in the 1950s Laurie M Brown, Max Dresden and Lillian Hoddeson; 2. Particle physics in the early 1950s Chen Ning Yang; 3. An historian's interest in particle physics J. L. Heilbron; Part II. Particle discoveries in cosmic rays; 4. Cosmic-ray cloud-chamber contributions to the discovery of the strange particles in the decade 1947-1957 George D. Rochester; 5. Cosmic-ray work with emulsions in the 1940s and 1950s Donald H. Perkins; Part III. High-energy nuclear physics; Learning about nucleon resonances with pion photoproduction Robert L. Walker; 7. A personal view of nucleon structure as revealed by electron scattering Robert Hofstadter; 8. Comments on electromagnetic form factors of the nucleon Robert G. Sachs and Kameshwar C. Wali; Part IV. The new laboratory; 9. The making of an accelerator physicist Matthew Sands; 10. Accelerator design and construction in the 1950s John P. Blewett; 11. Early history of the Cosmotron and AGS Ernest D. Courant; 12. Panel on accelerators and detectors in the 1950s Lawrence W. Jones, Luis W. Alvarez, Ugo Amaldi, Robert Hofstadter, Donald W. Kerst, Robert R. Wilson; 13. Accelerators and the Midwestern Universities Research Association in the 1950s Donald W. Kerst; 14. Bubbles, sparks and the postwar laboratory Peter Galison; 15. Development of the discharge (spark) chamber in Japan in the 1950s Shuji Fukui; 16. Early work at the Bevatron: a personal account Gerson Goldhaber; 17. The discovery of the antiproton Owen Chamberlain; 18. On the antiproton discovery Oreste Piccioni; Part V. The Strange Particles; 19. The hydrogen bubble chamber and the strange resonances Luis W. Alvarez; 20. A particular view of particle physics in the fifties Jack Steinberger; 21. Strange particles William Chinowsky; 22. Strange particles: production by Cosmotron beams as observed in diffusion cloud chambers William B. Fowler; 23. From the 1940s into the 1950s Abraham Pais; Part VI. Detection of the

  19. [Confirmative study of a French version of the Exercise Dependence Scale-revised with a French population].

    PubMed

    Allegre, B; Therme, P

    2008-10-01

    Since the first writings on excessive exercise, there has been an increased interest in exercise dependence. One of the major consequences of this increased interest has been the development of several definitions and measures of exercise dependence. The work of Veale [Does primary exercise dependence really exist? In: Annet J, Cripps B, Steinberg H, editors. Exercise addiction: Motivation for participation in sport and exercise.Leicester, UK: Br Psychol Soc; 1995. p. 1-5.] provides an advance for the definition and measure of exercise dependence. These studies have adapted the DSM-IV criteria for substance dependence to measure exercise dependence. The Exercise Dependence Scale-Revised is based on these diagnostic criteria, which are: tolerance; withdrawal effects; intention effect; lack of control; time; reductions in other activities; continuance. Confirmatory factor analyses of EDS-R provided support to present a measurement model (21 items loaded in seven factors) of EDS-R (Comparative Fit Index=0.97; Root mean Square Error of Approximation=0.05; Tucker-Lewis Index=0.96). The aim of this study was to examine the psychometric properties of a French version of the EDS-R [Factorial validity and psychometric examination of the exercise dependence scale-revised. Meas Phys Educ Exerc Sci 2004;8(4):183-201.] to test the stability of the seven-factor model of the original version with a French population. A total of 516 half-marathoners ranged in age from 17 to 74 years old (Mean age=39.02 years, ET=10.64), with 402 men (77.9%) and 114 women (22.1%) participated in the study. The principal component analysis results in a six-factor structure, which accounts for 68.60% of the total variance. Because principal component analysis presents a six-factor structure differing from the original seven-factor structure, two models were tested, using confirmatory factor analysis. The first model is the seven-factor model of the original version of the EDS-R and the second is the

  20. Numerical Modeling of Deep Mantle Convection: Advection and Diffusion Schemes for Marker Methods

    NASA Astrophysics Data System (ADS)

    Mulyukova, Elvira; Dabrowski, Marcin; Steinberger, Bernhard

    2013-04-01

    Thermal and chemical evolution of Earth's deep mantle can be studied by modeling vigorous convection in a chemically heterogeneous fluid. Numerical modeling of such a system poses several computational challenges. Dominance of heat advection over the diffusive heat transport, and a negligible amount of chemical diffusion results in sharp gradients of thermal and chemical fields. The exponential dependence of the viscosity of mantle materials on temperature also leads to high gradients of the velocity field. The accuracy of many numerical advection schemes degrades quickly with increasing gradient of the solution, while the computational effort, in terms of the scheme complexity and required resolution, grows. Additional numerical challenges arise due to a large range of length-scales characteristic of a thermochemical convection system with highly variable viscosity. To examplify, the thickness of the stem of a rising thermal plume may be a few percent of the mantle thickness. An even thinner filament of an anomalous material that is entrained by that plume may consitute less than a tenth of a percent of the mantle thickness. We have developed a two-dimensional FEM code to model thermochemical convection in a hollow cylinder domain, with a depth- and temperature-dependent viscosity representative of the mantle (Steinberger and Calderwood, 2006). We use marker-in-cell method for advection of chemical and thermal fields. The main advantage of perfoming advection using markers is absence of numerical diffusion during the advection step, as opposed to the more diffusive field-methods. However, in the common implementation of the marker-methods, the solution of the momentum and energy equations takes place on a computational grid, and nodes do not generally coincide with the positions of the markers. Transferring velocity-, temperature-, and chemistry- information between nodes and markers introduces errors inherent to inter- and extrapolation. In the numerical scheme

  1. New 40Ar/39Ar age progression for the Louisville hot spot trail and implications for inter-hot spot motion

    NASA Astrophysics Data System (ADS)

    Koppers, Anthony A. P.; Gowen, Molly D.; Colwell, Lauren E.; Gee, Jeffrey S.; Lonsdale, Peter F.; Mahoney, John J.; Duncan, Robert A.

    2011-12-01

    In this study we present 42 new 40Ar/39Ar incremental heating age determinations that contribute to an updated age progression for the Louisville seamount trail. Louisville is the South Pacific counterpart to the Hawaiian-Emperor seamount trail, both trails representing intraplate volcanism over the same time interval (˜80 Ma to present) and being examples of primary hot spot lineaments. Our data provide evidence for an age-progressive trend from 71 to 21 Ma. Assuming fixed hot spots, this makes possible a direct comparison to the Hawaiian-Emperor age progression and the most recent absolute plate motion (APM) model (WK08G) of Wessel and Kroenke (2008). We observe that for the Louisville seamount trail the measured ages are systematically older relative to both the WK08G model predictions and Hawaiian seamount ages, with offsets ranging up to 6 Myr. Taking into account the uncertainty about the duration of eruption and magmatic succession at individual Louisville volcanoes, these age offsets should be considered minimum estimates, as our sampling probably tended to recover the youngest lava flows. These large deviations point to either a contribution of inter-hot spot motion between the Louisville and Hawaiian hot spots or to a more easterly location of the Louisville hot spot than the one inferred in the WK08G model. Both scenarios are investigated in this paper, whereby the more eastern hot spot location (52.0°S, 134.5°W versus 52.4°S, 137.2°W) reduces the average age offset, but still results in a relatively large maximum offset of 3.7 Myr. When comparing the new ages to the APM models (S04P, S04G) by Steinberger et al. (2004) that attempt to compensate for the motion of hot spots in the Pacific (Hawaii) or globally (Hawaii, Louisville, Reunion and Walvis), the measured and predicted ages are more in agreement, showing only a maximum offset of 2.3 Myr with respect to the S04G model. At face value these more advanced APM models, which consider both plate and

  2. Humic first, A new theory on the origin of life

    NASA Astrophysics Data System (ADS)

    Daei, Mohammad Ali; Daei, Manijeh

    2016-04-01

    other enantiomers, because their spatial structure dictate, as did so regarding elemental selection. References: 1- Miller, Stanly L." production of amino acid under possible primitive Earth conditions" Science 117:528.(may 1953) 2- Encyclopedia Britannica website "carbonaceous contrite" October 17, 2014 3- Shapiro, Robert " A simpler origin for life" Science American February 12 . 2007 4- Pettit, Robert, "organic matter, humus, humate, humic acid, fulvic acid humin: their importance in soil fertility and plant health" 5- International Humic Substances Society website, " What are humic substances" 6- Humic, Fulvic and microbial balance: organic soil conditioning, by William R. Jackson 1993, pag 165-167 7- Steinberg, Christian E.W "Ecology of humic substances in freshwater-determination from geochemistry to ecological niches" (2003)

  3. Titanium (IV) sol-gel chemistry in varied gravity environments

    NASA Astrophysics Data System (ADS)

    Hales, Matthew; Martens, Wayde; Steinberg, Theodore

    . The test systems and experimental results obtained will be presented. 1. Okubo, T., Tsuchida, A., Okuda, T., Fujitsuna, K., Ishikawa, M., Morita, T., Tada, T. , Kinetic Analyses of Colloidal Crystallization in Microgravity -Aircraft Experiments. . Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1999. 153: p. 515-524. 2. Okubo, T., Tsuchida, A., Kobayashi, K., Kuno, A., Morita, T., Fujishima, M., Kohno, Y., Kinetic Study of the Formation Reaction of Colloidal Silica Spheres in Microgravity Using Aircraft. Colloid Polymer Science, 1999. 277(5): p. 474-478. 3. Pienaar, C.L., Chiffoleau, G. J. A., Follens, L. R. A., Martens, J. A., Kirschhock, C. E. A., Steinberg, T. A., Effect of Gravity on the Gelation of Silica Sols. Chem. Mater., 2007. 19(4): p. 660-664. 4. Smith, D.D., et al., Effect of Microgravity on the Growth of Silica Nanostructures. Langmuir, 2000. 16(26): p. 10055-10060. 5. Zhang, X., Johnson, D.P., Manerbino, A.R., Moore, J.J., Schowengerdt, F. , Recent Mi-crogravity Results in the Synthesis of Porous Materials. AIP Conference Proceedings (Space Technology and Applications International Forum-1999, Pt. 1), 1999. 458: p. 88-93. 6. Dunbar, P.B., Bendzko, N.J.,, 1H and 13C NMR observation of the reaction of acetic acid with titanium isopropoxide. Materials Chemistry and Physics, 1999. 59: p. 26-35. 7. Krunks, M., Oja, I., T˜nsuaadu, K., Es-Souni, M., Gruselle, M., Niinistü,. L, Thermoanalytical study of acetylacetonate-modified titanium (iv) isopropoxide as precursor for TiO2 films. Journal of Thermal Analysis and Calorimetry, 2005: p. 483-488. 8. Moran, P.D., Bowmaker, G. A., Cooney, R. P., Vibrational Spectra and Molecular Associa-tion of Titanium Tetraisopropoxide. Inorg. Chem., 1998. 37(1): p. 2741-2748. 9. Somogyvari, A., Serpone, N.,, Evidence for five-coordination in titanium(1V) complexes. A nuclear magnetic resonance investigation. Canadian Journal of Chemistry, 1977. 56: p. 316-319.

  4. Impact of different detachment topographies on pull-apart basin evolution - analog modelling and computer visualisation

    NASA Astrophysics Data System (ADS)

    Hoprich, M.; Decker, K.; Grasemann, B.; Sokoutis, D.; Willingshofer, E.

    2009-04-01

    floor. The surface of the model was photographed after each deformation increment through the experiment. Pictures of serial cross sections cut through the models in their final state every 4 cm were also taken and interpreted. The formation of en-echelon normal faults with relay ramps is observed in all models. These faults are arranged in an acute angle to the basin borders, according to a Riedel-geometry. In the case of an asymmetric basin they emerge within the non-moving fault block. Substantial differences between the models are the number, the distance and the angle of these Riedel faults, the length of the bounding strike-slip faults and the cross basin symmetry. A flat detachment produces straight fault traces, whereas inclined detachments (or inclined ramps) lead to "bending" of the normal faults, rollover and growth strata thickening towards the faults. Positions and the sizes of depocenters also vary, with depocenters preferably developing above ramp-flat-transitions. Depocenter thicknesses increase with ramp heights. A similar relation apparently exists in the natural Vienna basin, which shows ramp-like structures in the detachment just underneath large faults like the Steinberg normal fault and the associated depocenters. The 3-ramp-model also reveals segmentation of the basin above the lowermost ramp. The evolving structure is comparable to the Wiener Neustadt sub-basin in the southern part of the Vienna basin, which is underlain by a topographical high of the detachment. Cross sections through the ductile model show a strong disintergration into a horst-and-graben basin. The thin silicon putty base influences the overlying strata in a way that the basin - unlike the "dry" sand models - becomes very flat and shallow. The top view shows an irregular basin shape and no rhombohedral geometry, which characterises the Vienna basin. The ductile base also leads to a symmetrical distribution of deformation on both fault blocks, even though only one fault block is

  5. Application of a Multiscale Model of Tantalum Deformation at Megabar Pressures

    SciTech Connect

    Cavallo, R M; Park, H; Barton, N R; Remignton, B A; Pollaine, S M; Prisbrey, S T; Bernier, J V; May, M J; Maddox, B R; Swift, D W; Becker, R C; Olson, R T

    2010-05-13

    thickness indicating that localizations not captured in the overall simulation have probably become dominant, i.e., the target is likely breaking up. Application of the multiscale dislocation dynamics model as implemented in the Ares hydrodynamics code shows excellent agreement with both the pRad and Omega data. They also compare the Steinberg-Lund (SL), Preston-Tonks-Wallace (PTW), and Stainberg-Guinan (SG) models with the data. The PTW and SG models provide good fits to the pRad data but over-predict the growth (underestimate the strength) on the laser platform. The SL model under-predicts the pRad data and over-predicts the Omega data. The excellent agreement of the multiscale model with the data over two orders of magnitude in strain rate and more than a factor of two in pressure lends credibility to the model. They continue to stress the model by conducting experiments at 5 Mbars and beyond at the National Ignition Facility at LLNL in the near future.

  6. PREFACE: EmQM13: Emergent Quantum Mechanics 2013

    NASA Astrophysics Data System (ADS)

    2014-04-01

    these proceedings represent the talks of the invited speakers as written immediately after the symposium. The volume starts with a contribution by organizers Jan Walleczek and Gerhard Grössing, essentially explaining why emergent quantum mechanics, and other deterministic approaches to quantum theory, must be considered viable approaches in quantum foundations today. This is followed by the exposition of Stephen Adler's talk who introduced to a general audience key questions at the current frontiers of quantum mechanics during the opening evening (with the contents of his conference talk appearing elsewhere). The conference proceedings then continues with the presentations as given in their chronological order i.e. starting with the opening talk of the scientific program by Gerard 't Hooft. While the page number was restricted for all invited speakers, the paper by Jeff Tollaksen was given more space, as his invited collaborator Yakir Aharonov was unable to deliver a separate talk, in order to represent both contributions in one paper. Note that the talks of all speakers, including the talks of those who could not be represented in this volume (M. Arndt, B. Braverman, C. Brukner, S. Colin, Y. Couder, B. Poirier, A. Steinberg, G. Weihs and H. Wiseman) are freely available on the conference website as video presentations (http://www.emqm13.org). The organizers wish to express their gratitude to Siegfried Fussy and Herbert Schwabl from AINS for the organizational support. The organizers also wish to thank Bruce Fetzer, President and CEO, John E. Fetzer Memorial Trust, and the Members of the Board of Trustees, for their strong support and for funding this symposium. We also wish to thank the Austrian Academy of Sciences for allowing the symposium to be held on their premises, and Anton Zeilinger, President of the Austrian Academy of Sciences, for his welcome address. The expertise of the Members of the Scientific Advisory Board of the EmQM13 symposium, Ana Maria Cetto

  7. The "heartbeat of the proton"

    NASA Astrophysics Data System (ADS)

    Weisskopf, Victor F.

    Once Nino came to my office to tell me about his ideas of studying lepton pair production at PS. I was still not Director General, but Research Director at CERN. In addition to (e+e-) and (μ+μ-) pairs, he wanted to search for (e±μ∓) pairs as a signature of a new lepton carrying its own lepton number. He told me that if such a lepton existed with one GeV mass, it would have escaped detection in hadron accelerator experiments for two reasons: i) it would decay with a lifetime of order 10-11 sec and ii) because there is no π → μ mechanism for such a heavy new lepton: for its production a time-like photon would be needed. Time-like photons could be produced in hadronic interactions: for example in (bar{p}p) annihilation. This was before Lederman-Schwartz and Steinberger had discovered the two neutrinos. To think of a "sequential" Heavy Lepton and to work out the possible ways to get it in a hadron machine was for me extremely interesting Nino had just finished his first high precision work on the muon (g-2). It was some time after the Rochester Conference in 1960. I gave Nino the following suggestion: if you want to search for something so revolutionary as a Heavy Lepton carrying its own lepton number you should work out a proposal for a series of experiments where the study of lepton pairs (e+e-) and (μ+μ-) could be justified in terms of physics accepted by the community. In addition a high intensity antiproton beam was needed. He came later to tell me that he had two very good friends, both excellent engineers: Mario Morpurgo and Guido Petrucci. A very high intensity antiproton beam could be built to study the electromagnetic form factor of the proton in the time-like region. If the proton was "point-like" in the time-like region, the rate of time-like photons yielding (e+e-) and (μ+μ-) pairs could be accessible to experimental observation, thus allowing to establish some limits on the new Heavy Lepton mass, or to see it, via the (e±μ∓) channel. The

  8. Life cycle assessment in support of sustainable transportation

    NASA Astrophysics Data System (ADS)

    Eckelman, Matthew J.

    2013-06-01

    cycle GHG and air pollutant emissions. A related study in Toronto on life cycle energy use and GHG emissions for high- and low-density development strategies found a ~60% difference in GHG emissions, largely due to transportation (Norman et al 2006). System dynamics and agent-based models may complement LCA in capturing long-term effects of transportation strategies as they are inherently dynamic (Stepp et al 2009), and can internalize spatially resolved decisions about where to settle and work (Waddell 2002). Transportation planning decisions have both direct and indirect, spatially distributed, often long-term effects on our health and our environment. The accompanying work by Chester et al (2013) provides a well-documented case study that highlights the potential of LCA as a rich source of decision support. References Chester M, Pincetl S, Elizabeth Z, Eisenstein W and Matute J 2013 Infrastructure and automobile shifts: positioning transit to reduce life-cycle environmental impacts for urban sustainability goals Environ. Res. Lett. 8 015041 Chester M V and Horvath A 2009 Environmental assessment of passenger transportation should include infrastructure and supply chains Environ. Res. Lett. 4 024008 Fargione J, Hill J, Tilman D, Polasky S and Hawthorne P 2008 Land clearing and the biofuel carbon debt Science 319 1235-8 Kennedy C, Steinberger J, Gasson B, Hansen Y, Hillman T, Havránek M, Pataki D, Phdungsilp A, Ramaswami A and Mendez G V 2009 Greenhouse gas emissions from global cities Environ. Sci. Technol. 43 7297-302 Kunstler J H 1994 Geography of Nowhere: The Rise and Decline of America's Man-Made Landscape (New York: Free Press) Mashayekh Y, Jaramillo P, Samaras C, Hendrickson C T, Blackhurst M, MacLean H L and Matthews H S 2012 Potentials for sustainable transportation in cities to alleviate climate change impacts Environ. Sci. Technol. 46 2529-37 Mutel C L and Hellweg S 2009 Regionalized life cycle assessment: computational methodology and application to

  9. PREFACE: Turbulent Mixing and Beyond Turbulent Mixing and Beyond

    NASA Astrophysics Data System (ADS)

    Abarzhi, Snezhana I.; Gauthier, Serge; Rosner, Robert

    2008-10-01

    , Italy) V Steinberg (Weiznmann Institute, Israel) A L Velikovich (Naval Research Laboratory, USA) P K Yeung (Georgia Institute of Technology, USA) F A Williams (University of California at San Diego, USA) We would like to thank all the authors and the referees for their contributions to this Topical Issue and for offering their expertise, time and effort We cordially invite the reader to take a look at this Topical Issue for information on the frontiers of theoretical, numerical and experimental research and technology The Organizing Committee hopes the TMB Conference will serve to advance the state-of-the-art in understanding of fundamental physical properties of turbulent mixing and turbulence in unsteady flows and will have an impact on predictive modeling capabilities, physical description and, ultimately, control of these complex processes Snezhana I Abarzhi, Serge Gauthier, Robert Rosner Chicago, 20 Nov 2008