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Sample records for aharony bergman jafferis

  1. Aharony-Bergman-Jafferis-Maldacena Wilson Loops in the Fermi Gas Approach

    NASA Astrophysics Data System (ADS)

    Klemm, Albrecht; Mariño, Marcos; Soroush, Masoud

    2013-02-01

    The matrix model of the Aharony-Bergman-Jafferis-Maldacena theory can be formulated in terms of an ideal Fermi gas with a non-trivial one-particle Hamiltonian. We show that, in this formalism, vacuum expectation values (vevs) of Wilson loops correspond to averages of operators in the statistical-mechanical problem. This makes it possible to calculate these vevs at all orders in 1/N, up to exponentially small corrections, and for arbitrary Chern-Simons coupling, by using the Wentzel- Kramer-Brillouin expansion.We present explicit results for the vevs of 1/6 and the 1/2 Bogomolnyi- Prasad-Sommerfield Wilson loops, at any winding number, in terms of Airy functions. Our expressions are shown to reproduce the low genus results obtained previously in the 't Hooft expansion.

  2. Towards a realization of the condensed-matter-gravity correspondence in string theory via consistent Abelian truncation of the Aharony-Bergman-Jafferis-Maldacena model.

    PubMed

    Mohammed, Asadig; Murugan, Jeff; Nastase, Horatiu

    2012-11-01

    We present an embedding of the three-dimensional relativistic Landau-Ginzburg model for condensed matter systems in an N = 6, U(N) × U(N) Chern-Simons-matter theory [the Aharony-Bergman-Jafferis-Maldacena model] by consistently truncating the latter to an Abelian effective field theory encoding the collective dynamics of O(N) of the O(N(2)) modes. In fact, depending on the vacuum expectation value on one of the Aharony-Bergman-Jafferis-Maldacena scalars, a mass deformation parameter μ and the Chern-Simons level number k, our Abelianization prescription allows us to interpolate between the Abelian Higgs model with its usual multivortex solutions and a Ø(4) theory. We sketch a simple condensed matter model that reproduces all the salient features of the Abelianization. In this context, the Abelianization can be interpreted as giving a dimensional reduction from four dimensions.

  3. Towards a realization of the condensed-matter-gravity correspondence in string theory via consistent Abelian truncation of the Aharony-Bergman-Jafferis-Maldacena model.

    PubMed

    Mohammed, Asadig; Murugan, Jeff; Nastase, Horatiu

    2012-11-01

    We present an embedding of the three-dimensional relativistic Landau-Ginzburg model for condensed matter systems in an N = 6, U(N) × U(N) Chern-Simons-matter theory [the Aharony-Bergman-Jafferis-Maldacena model] by consistently truncating the latter to an Abelian effective field theory encoding the collective dynamics of O(N) of the O(N(2)) modes. In fact, depending on the vacuum expectation value on one of the Aharony-Bergman-Jafferis-Maldacena scalars, a mass deformation parameter μ and the Chern-Simons level number k, our Abelianization prescription allows us to interpolate between the Abelian Higgs model with its usual multivortex solutions and a Ø(4) theory. We sketch a simple condensed matter model that reproduces all the salient features of the Abelianization. In this context, the Abelianization can be interpreted as giving a dimensional reduction from four dimensions. PMID:23215268

  4. Weighted Bergman Kernels and Quantization}

    NASA Astrophysics Data System (ADS)

    Engliš, Miroslav

    Let Ω be a bounded pseudoconvex domain in CN, φ, ψ two positive functions on Ω such that - log ψ, - log φ are plurisubharmonic, and z∈Ω a point at which - log φ is smooth and strictly plurisubharmonic. We show that as k-->∞, the Bergman kernels with respect to the weights φkψ have an asymptotic expansion for x,y near z, where φ(x,y) is an almost-analytic extension of &\\phi(x)=φ(x,x) and similarly for ψ. Further, . If in addition Ω is of finite type, φ,ψ behave reasonably at the boundary, and - log φ, - log ψ are strictly plurisubharmonic on Ω, we obtain also an analogous asymptotic expansion for the Berezin transform and give applications to the Berezin quantization. Finally, for Ω smoothly bounded and strictly pseudoconvex and φ a smooth strictly plurisubharmonic defining function for Ω, we also obtain results on the Berezin-Toeplitz quantization.

  5. Reversible Bergman cyclization by atomic manipulation

    NASA Astrophysics Data System (ADS)

    Schuler, Bruno; Fatayer, Shadi; Mohn, Fabian; Moll, Nikolaj; Pavliček, Niko; Meyer, Gerhard; Peña, Diego; Gross, Leo

    2016-03-01

    The Bergman cyclization is one of the most fascinating rearrangements in chemistry, with important implications in organic synthesis and pharmacology. Here we demonstrate a reversible Bergman cyclization for the first time. We induced the on-surface transformation of an individual aromatic diradical into a highly strained ten-membered diyne using atomic manipulation and verified the products by non-contact atomic force microscopy with atomic resolution. The diyne and diradical were stabilized by using an ultrathin NaCl film as the substrate, and the diyne could be transformed back into the diradical. Importantly, the diradical and the diyne exhibit different reactivity, electronic, magnetic and optical properties associated with the changes in the bond topology, and spin multiplicity. With this reversible, triggered Bergman cyclization we demonstrated switching on demand between the two reactive intermediates by means of selective C-C bond formation or cleavage, which opens up the field of radical chemistry for on-surface reactions by atomic manipulation.

  6. Stability and integration over Bergman metrics

    NASA Astrophysics Data System (ADS)

    Klevtsov, Semyon; Zelditch, Steve

    2014-07-01

    We study partition functions of random Bergman metrics, with the actions defined by a class of geometric functionals known as `stability functions'. We introduce a new stability invariant — the critical value of the coupling constant — defined as the minimal coupling constant for which the partition function converges. It measures the minimal degree of stability of geodesic rays in the space the Bergman metrics, with respect to the action. We calculate this critical value when the action is the ν-balancing energy, and show that on a Riemann surface of genus h.

  7. Bergman kernel, balanced metrics and black holes

    NASA Astrophysics Data System (ADS)

    Klevtsov, Semyon

    In this thesis we explore the connections between the Kahler geometry and Landau levels on compact manifolds. We rederive the expansion of the Bergman kernel on Kahler manifolds developed by Tian, Yau, Zelditch, Lu and Catlin, using path integral and perturbation theory. The physics interpretation of this result is as an expansion of the projector of wavefunctions on the lowest Landau level, in the special case that the magnetic field is proportional to the Kahler form. This is a geometric expansion, somewhat similar to the DeWitt-Seeley-Gilkey short time expansion for the heat kernel, but in this case describing the long time limit, without depending on supersymmetry. We also generalize this expansion to supersymmetric quantum mechanics and more general magnetic fields, and explore its applications. These include the quantum Hall effect in curved space, the balanced metrics and Kahler gravity. In particular, we conjecture that for a probe in a BPS black hole in type II strings compactified on Calabi-Yau manifolds, the moduli space metric is the balanced metric.

  8. Looking for a Matrix model for ABJM theory

    SciTech Connect

    Mohammed, Asadig; Murugan, Jeff; Nastase, Horatiu

    2010-10-15

    Encouraged by the recent construction of fuzzy sphere solutions in the Aharony, Bergman, Jafferis, and Maldacena (ABJM) theory, we re-analyze the latter from the perspective of a Matrix-like model. In particular, we argue that a vortex solution exhibits properties of a supergraviton, while a kink represents a 2-brane. Other solutions are also consistent with the Matrix-type interpretation. We study vortex scattering and compare with graviton scattering in the massive ABJM background, however our results are inconclusive. We speculate on how to extend our results to construct a Matrix theory of ABJM.

  9. The Weighted Super Bergman Kernels Over the Supermatrix Spaces

    NASA Astrophysics Data System (ADS)

    Feng, Zhiming

    2015-12-01

    The purpose of this paper is threefold. Firstly, using Howe duality for , we obtain integral formulas of the super Schur functions with respect to the super standard Gaussian distributions. Secondly, we give explicit expressions of the super Szegö kernels and the weighted super Bergman kernels for the Cartan superdomains of type I. Thirdly, combining these results, we obtain duality relations of integrals over the unitary groups and the Cartan superdomains, and the marginal distributions of the weighted measure.

  10. Competition of Bergman-type approximants with other packing motifs in the Cu-Zr system

    NASA Astrophysics Data System (ADS)

    Zhang, Feng; Jin, Min; Wang, X. W.; Wang, Cai-Zhuang; Kramer, M. J.; Mendelev, M. I.; Ho, Kai-Ming

    2012-02-01

    Knowledge about the topological and chemical ordering in metallic liquids and glasses is essential in predicting phase selection and understanding glass formation dynamics. Taking the Cu-Zr system as an example, previous studies have established Bergman-type medium-range ordering (MRO) from a structural analysis with cluster alignment methods [1]. In this study, we examine the thermodynamic stability of a crystalline approximant of Bergman-type quasicrystals [2] against packing geometries existing in other intermetallic compounds for a wide range of Cu compositions. The most stable structures for each structural motif at each Cu composition are obtained using an efficient genetic-algorithm search. Our results show that the Bergman-type approximant structure is thermodynamically favored over other packing geometries at the glass-forming region with Cu compositions around 65%, reaffirming the Bergman-type MRO is the lowest energy in Cu-Zr glasses.[4pt] [1] X. W. Fang, C. Z. Wang, Y. X. Yao, Z. J. Ding, and K. M. Ho, Phys. Rev. B 82, 184204 (2010).[0pt] [2] G. Bergman J. L. T. Waugh, and L. Pauling, Acta Cryst. 10, 254 (1957).

  11. Unciaphenol, an Oxygenated Analogue of the Bergman Cyclization Product of Uncialamycin Exhibits Anti-HIV Activity.

    PubMed

    Williams, David E; Bottriell, Helen; Davies, Julian; Tietjen, Ian; Brockman, Mark A; Andersen, Raymond J

    2015-11-01

    Unciaphenol (2), an oxygenated analogue of the Bergman cyclization product of the enediyne uncialamycin (1), has been isolated along with 1 from cultures of the actinomycete Streptomyces uncialis. It is proposed that the C-22 OH substituent in 2 might arise from the attack of a nucleophilic oxygen species on the p-benzyne diradical intermediate IA in the Bergman cyclization of 1. 2 shows in vitro anti-HIV activity against viral strains that are resistant to clinically utilized anti-retroviral therapies.

  12. Vortex loop operators, M2-branes and holography

    NASA Astrophysics Data System (ADS)

    Drukker, Nadav; Gomis, Jaume; Young, Donovan

    2009-03-01

    We construct vortex loop operators in the three-dimensional Script N = 6 supersymmetric Chern-Simons theory recently constructed by Aharony, Bergman, Jafferis and Maldacena. These disorder loop operators are specified by a vortex-like singularity for the scalar and gauge fields along a one dimensional curve in spacetime. We identify the 1/2, 1/3 and 1/6 BPS loop operators in the Chern-Simons theory with excitations of M-theory corresponding to M2-branes ending along a curve on the boundary of AdS4 × S7/Bbb Zk. The vortex loop operators can also be given a purely geometric description in terms of regular ``bubbling'' solutions of eleven dimensional supergravity which are asymptotically AdS4 × S7/Bbb Zk.

  13. Exact slope and interpolating functions in N=6 supersymmetric Chern-Simons theory.

    PubMed

    Gromov, Nikolay; Sizov, Grigory

    2014-09-19

    Using the quantum spectral curve approach we compute, exactly, an observable (called slope function) in the planar Aharony-Bergman-Jafferis-Maldacena theory in terms of an unknown interpolating function h(λ) which plays the role of the coupling in any integrability based calculation in this theory. We verified our results with known weak coupling expansion in the gauge theory and with the results of semiclassical string calculations. Quite surprisingly at strong coupling the result is given by an explicit rational function of h(λ) to all orders. By comparing the structure of our result with that of an exact localization based calculation for a similar observable in Marino and Putrov [J. High Energy Phys. 06 (2010) 011], we conjecture an exact expression for h(λ). PMID:25279619

  14. Exact slope and interpolating functions in N=6 supersymmetric Chern-Simons theory.

    PubMed

    Gromov, Nikolay; Sizov, Grigory

    2014-09-19

    Using the quantum spectral curve approach we compute, exactly, an observable (called slope function) in the planar Aharony-Bergman-Jafferis-Maldacena theory in terms of an unknown interpolating function h(λ) which plays the role of the coupling in any integrability based calculation in this theory. We verified our results with known weak coupling expansion in the gauge theory and with the results of semiclassical string calculations. Quite surprisingly at strong coupling the result is given by an explicit rational function of h(λ) to all orders. By comparing the structure of our result with that of an exact localization based calculation for a similar observable in Marino and Putrov [J. High Energy Phys. 06 (2010) 011], we conjecture an exact expression for h(λ).

  15. Exact results for Wilson loops in orbifold ABJM theory

    NASA Astrophysics Data System (ADS)

    Ouyang, Hao; Wu, Jun-Bao; Zhang, Jia-Ju

    2016-08-01

    We investigate the exact results for circular 1/4 and 1/2 BPS Wilson loops in the d = 3 mathcal = 4 super Chern-Simons-matter theory that could be obtained by orbifolding Aharony-Bergman-Jafferis-Maldacena (ABJM) theory. The partition function of the mathcal = 4 orbifold ABJM theory has been computed previously in the literature. In this paper, we re-derive it using a slightly different method. We calculate the vacuum expectation values of the circular 1/4 BPS Wilson loops in fundamental representation and of circular 1/2 BPS Wilson loops in arbitrary representations. We use both the saddle point approach and Fermi gas approach. The results for Wilson loops are in accord with the available gravity results. Supported by NSFC (11222549, 11575202), K. C. Wong Education Foundation and Youth Innovation Promotion Association of CAS (2011016)

  16. Quantum spectral curve of the N=6 supersymmetric Chern-Simons theory.

    PubMed

    Cavaglià, Andrea; Fioravanti, Davide; Gromov, Nikolay; Tateo, Roberto

    2014-07-11

    Recently, it was shown that the spectrum of anomalous dimensions and other important observables in planar N=4 supersymmetric Yang-Mills theory are encoded into a simple nonlinear Riemann-Hilbert problem: the Pμ system or quantum spectral curve. In this Letter, we extend this formulation to the N=6 supersymmetric Chern-Simons theory introduced by Aharony, Bergman, Jafferis, and Maldacena. This may be an important step towards the exact determination of the interpolating function h(λ) characterizing the integrability of this model. We also discuss a surprising relation between the quantum spectral curves for the N=4 supersymmetric Yang-Mills theory and the N=6 supersymmetric Chern-Simons theory considered here.

  17. Direct and inverse theorems of rational approximation in the Bergman space

    NASA Astrophysics Data System (ADS)

    Mardvilko, Tat'yana S.; Pekarskii, Alexandr A.

    2011-09-01

    For positive numbers p and \\mu let A_{p,\\mu} denote the Bergman space of analytic functions in the half-plane \\Pi:=\\{z\\in C:\\operatorname{Im} z>0\\}. For f\\in A_{p,\\mu} let R_n (f)_{p,\\mu} be the best approximation by rational functions of degree at most n. Also let \\alpha\\in R and \\tau>0 be numbers such that \\alpha+\\mu=\\frac{1}{\\tau}-\\frac{1}{p}>0 and \\frac{1}{p}+\\mu\

  18. Application of the Bergman-Milton theory of bounds to the permittivity of rocks

    NASA Astrophysics Data System (ADS)

    Korringa, J.; LaTorraca, G. A.

    1986-10-01

    The permittivity of brine-saturated porous rocks below 2 GHz varies with frequency in a way that is linked closely to the pore geometry. The theories of bounds of the permittivity by Bergman and by Milton, based on Bergman's work on two-component composites, impose restrictions on this frequency dependence. We give a detailed and systematic analysis of these restrictions for this special case. We show to what extent the conductivity at low frequencies, combined with a measured value of the permittivity at an intermediate frequency, restricts the permittivity at all other frequencies. We establish a scaling law, according to which the permittivity depends on the brine conductivity σ2 and the frequency ω, only through the ratio σ2/ω, to a good approximation. We apply the analysis to data on sandstones by Poley, Nooteboom, and de Waal. As a further application of this theory, we derive bounds for the electrical or thermal conductivity of a two-component composite using the values that this same property would have if either of the components were an insulator.

  19. Effective Wess Zumino Witten action for edge states of quantum Hall systems on Bergman ball

    NASA Astrophysics Data System (ADS)

    Daoud, Mohammed; Jellal, Ahmed

    2007-03-01

    Using a group theory approach, we investigate the basic features of the Landau problem on the Bergman ball B. This can be done by considering a system of particles living on B in the presence of an uniform magnetic field B and realizing the ball as the coset space SU(k,1)/U(k). In quantizing the theory on B, we define the wavefunctions as the Wigner D-functions satisfying a set of suitable constraints. The corresponding Hamiltonian is mapped in terms of the right translation generators. In the lowest Landau level, we obtain the wavefunctions as the SU(k,1) coherent states. This are used to define the star product, density matrix and excitation potential in higher dimensions. With these ingredients, we construct a generalized effective Wess-Zumino-Witten action for the edge states and discuss their nature.

  20. Trajectory Calculations for Bergman Cyclization Predict H/D Kinetic Isotope Effects Due to Nonstatistical Dynamics in the Product.

    PubMed

    Doubleday, Charles; Boguslav, Mayla; Howell, Caronae; Korotkin, Scott D; Shaked, David

    2016-06-22

    An unusual H/D kinetic isotope effect (KIE) is described, in which isotopic selectivity arises primarily from nonstatistical dynamics in the product. In DFT-based quasiclassical trajectories of Bergman cyclization of (Z)-3-hexen-1,5-diyne (1) at 470 K, the new CC bond retains its energy, and 28% of nascent p-benzyne recrosses back to the enediyne on a vibrational time scale. The competing process of intramolecular vibrational redistribution (IVR) in p-benzyne is too slow to prevent this. Deuteration increases the rate of IVR, which decreases the fraction of recrossing and increases the yield of statistical (trapable) p-benzyne, 2. Trapable yields for three isotopomers of 2 range from 72% to 86%. The resulting KIEs for Bergman cyclization differ substantially from KIEs predicted by transition state theory, which suggests that IVR in this reaction can be studied by conventional KIEs. Leakage of vibrational zero point energy (ZPE) into the reaction coordinate was probed by trajectories in which initial ZPE in the CH/CD stretching modes was reduced by 25%. This did not change the predicted KIEs.

  1. Bergman Clusters, Multiple Bonds, and Defect Planes: Synthetic Outcomes of Chemical Frustration in Ternary Intermetallic Systems

    NASA Astrophysics Data System (ADS)

    Hadler, Amelia Beth

    Intermetallics crystallize in a variety of complex structures, many of which show unusual bonding or intriguing properties. Understanding what factors drive this structural chemistry would be a valuable step towards designing new intermetallics with specific structures or properties. One pathway towards understanding and predicting the structures of complex intermetallics is chemical frustration, a design tool which harnesses competition between incompatible bonding or packing modes to induce complexity in ternary intermetallic systems. The research outlined in this thesis focuses on developing chemical frustration through exploratory synthesis in ternary systems designed to induce frustration between the tetrahedral close packing of many intermetallics and the simple cubic packing seen for ionic salts or elemental metals. Syntheses in three systems yielded six new ternary intermetallics, four of which crystallize in novel structure types. Three were discovered in the Ca-Cu-Cd system: Ca5Cu2Cd and Ca2Cu 2Cd9, which adopt ternary variants of binary structures, and Ca10Cu2Cd27, which crystallizes in a new structure built from Bergman clusters. All three structures can be traced to electronic packing frustration induced by the similar electronegativities but different metallic radii of Cu and Cd. The Gd-Fe-C system yielded the new carbometalate Gd13Fe 10C13 and an oxycarbide derivative. These phases crystallize in structures built from Gd tricapped trigonal prisms interpenetrated by an Fe-C network. Theoretical analyses reveal that Fe-Fe and Fe-C multiple bonding is found throughout this network. A theoretical investigation of similar carbides uncovers additional metal-metal, metal-carbon, and carbon-carbon multiple bonding. This unusual bonding stabilizes the carbides by satisfying preferred electron counts for their transition metal sites. One new phase, Mg4.5Pd5Ge1.5, was found in the Mg-Pd-Ge system. Its structure is closely related to the CsCl-type structure of

  2. Further Clarification on the Hom, Mitchell, Lee, and Griffeth (2012) Model: Reply to Bergman, Payne, and Boswell (2012) and Maertz (2012)

    ERIC Educational Resources Information Center

    Griffeth, Rodger W.; Lee, Thomas W.; Mitchell, Terence R.; Hom, Peter W.

    2012-01-01

    In this article, we reply to Bergman, Payne, and Boswell (2012) and Maertz (2012), who commented on our reconceptualization of the employee turnover criterion and proximal withdrawal states (Hom, Mitchell, Lee, & Griffeth, 2012). We agree with some points (e.g., anticipated destinations) but take issue with others (e.g., turnover intentions as…

  3. Construction and classification of novel BPS Wilson loops in quiver Chern-Simons-matter theories

    NASA Astrophysics Data System (ADS)

    Ouyang, Hao; Wu, Jun-Bao; Zhang, Jia-ju

    2016-09-01

    In this paper we construct and classify novel Drukker-Trancanelli (DT) type BPS Wilson loops along infinite straight lines and circles in N = 2 , 3 quiver superconformal Chern-Simons-matter theories, Aharony-Bergman-Jafferis-Maldacena (ABJM) theory, and N = 4 orbifold ABJM theory. Generally we have four classes of Wilson loops, and all of them preserve the same supersymmetries as the BPS Gaiotto-Yin (GY) type Wilson loops. There are several free complex parameters in the DT type BPS Wilson loops, and for two classes of Wilson loops in ABJM theory and N = 4 orbifold ABJM theory there are supersymmetry enhancements at special values of the parameters. We check that the differences of the DT type and GY type Wilson loops are Q-exact with Q being some supercharges preserved by both the DT type and GY type Wilson loops. The results would be useful to calculate vacuum expectation values of the DT type Wilson loops in matrix models if they are still BPS quantum mechanically.

  4. On three-algebra and bi-fundamental matter amplitudes and integrability of supergravity

    NASA Astrophysics Data System (ADS)

    Huang, Yu-tin; Johansson, Henrik; Lee, Sangmin

    2013-11-01

    We explore tree-level amplitude relations for SU( N) × SU( M) bi-fundamental matter theories. Embedding the group-theory structure in a Lie three-algebra, we derive Kleiss-Kuijf-like relations for bi-fundamental matter theories in general dimension. We investigate the three-algebra color-kinematics duality for these theories. Unlike the Yang-Mills two-algebra case, the three-algebra Bern-Carrasco-Johansson relations depend on the spacetime dimension and on the detailed symmetry properties of the structure constants. We find the presence of such relations in three and two dimensions, and absence in D > 3. Surprisingly, beyond six point, such relations are absent in the Aharony-Bergman-Jafferis-Maldacena theory for general gauge group, while the Bagger-Lambert-Gustavsson theory, and its supersymmetry truncations, obey the color-kinematics duality like clockwork. At four and six points the relevant partial amplitudes of the two theories are bijectively related, explaining previous results in the literature. In D = 2 the color-kinematics duality gives results consistent with integrability of two-dimensional = 16 supergravity: the four-point amplitude satisfies a Yang-Baxter equation; the six- and eight-point amplitudes vanish for certain kinematics away from factorization channels, as expected from integrability.

  5. Adding flavor to AdS4/CFT3

    NASA Astrophysics Data System (ADS)

    Ammon, Martin; Erdmenger, Johanna; Meyer, René; O'Bannon, Andy; Wrase, Timm

    2009-11-01

    Aharony, Bergman, Jafferis, and Maldacena have proposed that the low-energy description of multiple M2-branes at a Bbb C4/Bbb Zk singularity is a (2+1)-dimensional Script N = 6 supersymmetric U(Nc) × U(Nc) Chern-Simons matter theory, the ABJM theory. In the large-Nc limit, its holographic dual is supergravity in AdS4 × S7/Bbb Zk. We study various ways to add fields that transform in the fundamental representation of the gauge groups, i.e. flavor fields, to the ABJM theory. We work in a probe limit and perform analyses in both the supergravity and field theory descriptions. In the supergravity description we find a large class of supersymmetric embeddings of probe flavor branes. In the field theory description, we present a general method to determine the couplings of the flavor fields to the fields of the ABJM theory. We then study four examples in detail: codimension-zero Script N = 3 supersymmetric flavor, described in supergravity by Kaluza-Klein monopoles or D6-branes; codimension-one Script N = (0,6) supersymmetric chiral flavor, described by D8-branes; codimension-one Script N = (3,3) supersymmetric non-chiral flavor, described by M5/D4-branes; codimension-two Script N = 4 supersymmetric flavor, described by M2/D2-branes. Finally we discuss special physical equivalences between brane embeddings in M-theory, and their interpretation in the field theory description.

  6. Multimatrix models and tri-Sasaki Einstein spaces

    SciTech Connect

    Herzog, Christopher P.; Pufu, Silviu S.; Tesileanu, Tiberiu; Klebanov, Igor R.

    2011-02-15

    Localization methods reduce the path integrals in N{>=}2 supersymmetric Chern-Simons gauge theories on S{sup 3} to multimatrix integrals. A recent evaluation of such a two-matrix integral for the N=6 superconformal U(N)xU(N) Aharony-Bergman-Jafferis-Maldacena theory produced detailed agreement with the AdS/CFT correspondence, explaining, in particular, the N{sup 3/2} scaling of the free energy. We study a class of p-matrix integrals describing N=3 superconformal U(N){sup p} Chern-Simons gauge theories. We present a simple method that allows us to evaluate the eigenvalue densities and the free energies in the large N limit keeping the Chern-Simons levels k{sub i} fixed. The dual M-theory backgrounds are AdS{sub 4}xY, where Y are seven-dimensional tri-Sasaki Einstein spaces specified by the k{sub i}. The gravitational free energy scales inversely with the square root of the volume of Y. We find a general formula for the p-matrix free energies that agrees with the available results for volumes of the tri-Sasaki Einstein spaces Y, thus providing a thorough test of the corresponding AdS{sub 4}/CFT{sub 3} dualities. This formula is consistent with the Seiberg duality conjectured for Chern-Simons gauge theories.

  7. Essential oil of Nepeta x faassenii Bergmans ex Stearn (N. mussinii Spreng. x N. nepetella L.): a comparison study.

    PubMed

    Radulović, Niko; Blagojević, Polina D; Rabbitt, Kevin; Menezes, Fabio de Sousa

    2011-07-01

    Analysis (GC and GC/MS) of an essential oil sample obtained from dry leaves of Nepeta x faassenii Bergmans ex Steam, a hybrid species produced by crossbreeding N. mussinii Spreng. with N. nepetella L., led to the identification of 109 constituents that represented 95.9% of the oil. The major constituents were 4aalpha,7alpha,7aalpha-nepetalactone (67.8%), 1,8-cineole (6.6%), germacrene D (4.8%), beta-pinene (2.7%), (E)-beta-ocimene (2.6%), 4aalpha,7beta,7aalpha-nepetalactone (2.3%) and (E)-beta-farnesene (1.0%). Chemical composition of the oil was compared, using multivariate statistical analyses (MVA) with those of the oils of other Nepeta taxa, in particular N. mussinii and N. nepetella. This was done in order to explore the mode of inheritance of the monoterpene biosynthetic apparatus of N. faassenii. Chemical composition of the volatiles of a Nepeta taxon (different populations) can be subject to variation due to environmental and geographical factors. To accommodate this fact in the MVAs, along side with N. faassenii essential oil, additional 6 oils (3 different populations of N. nuda L. and N. cataria L. from Serbia) were included in this study (isolated and analyzed (chemically and statistically)). The MVA analyses recognized N. faassenii as being closely related to both N. mussinii and N. nepetella. If the relative content of oil constituents per plant and not per chromatogram were used as variables in the MVA (this was done by simple multiplication of the yields and relative percentages of components) a higher degree of mutual similarity (in respect to the monoterpene biosynthesis) of N. faassenii to N. mussinii, than to the other parent species, was observed.

  8. Essential oil of Nepeta x faassenii Bergmans ex Stearn (N. mussinii Spreng. x N. nepetella L.): a comparison study.

    PubMed

    Radulović, Niko; Blagojević, Polina D; Rabbitt, Kevin; Menezes, Fabio de Sousa

    2011-07-01

    Analysis (GC and GC/MS) of an essential oil sample obtained from dry leaves of Nepeta x faassenii Bergmans ex Steam, a hybrid species produced by crossbreeding N. mussinii Spreng. with N. nepetella L., led to the identification of 109 constituents that represented 95.9% of the oil. The major constituents were 4aalpha,7alpha,7aalpha-nepetalactone (67.8%), 1,8-cineole (6.6%), germacrene D (4.8%), beta-pinene (2.7%), (E)-beta-ocimene (2.6%), 4aalpha,7beta,7aalpha-nepetalactone (2.3%) and (E)-beta-farnesene (1.0%). Chemical composition of the oil was compared, using multivariate statistical analyses (MVA) with those of the oils of other Nepeta taxa, in particular N. mussinii and N. nepetella. This was done in order to explore the mode of inheritance of the monoterpene biosynthetic apparatus of N. faassenii. Chemical composition of the volatiles of a Nepeta taxon (different populations) can be subject to variation due to environmental and geographical factors. To accommodate this fact in the MVAs, along side with N. faassenii essential oil, additional 6 oils (3 different populations of N. nuda L. and N. cataria L. from Serbia) were included in this study (isolated and analyzed (chemically and statistically)). The MVA analyses recognized N. faassenii as being closely related to both N. mussinii and N. nepetella. If the relative content of oil constituents per plant and not per chromatogram were used as variables in the MVA (this was done by simple multiplication of the yields and relative percentages of components) a higher degree of mutual similarity (in respect to the monoterpene biosynthesis) of N. faassenii to N. mussinii, than to the other parent species, was observed. PMID:21834248

  9. Further clarification on the Hom, Mitchell, Lee, and Griffeth (2012) model: Reply to Bergman, Payne, and Boswell (2012) and Maertz (2012).

    PubMed

    Griffeth, Rodger W; Lee, Thomas W; Mitchell, Terence R; Hom, Peter W

    2012-09-01

    In this article, we reply to Bergman, Payne, and Boswell (2012) and Maertz (2012), who commented on our reconceptualization of the employee turnover criterion and proximal withdrawal states (Hom, Mitchell, Lee, & Griffeth, 2012). We agree with some points (e.g., anticipated destinations) but take issue with others (e.g., turnover intentions as the criterion). Nonetheless, our aim is to clarify our integrative formulation about mindsets for organizational participation and withdrawal. In our view, the current process of "article-commentaries-reply" advances our collective understanding of staying and leaving, which is of longstanding interest to scholars in industrial and organizational psychology, organizational behavior, and human resource management. PMID:22925141

  10. Structural refinement of 1/1 bcc approximants to quasicrystals: Bergman-type W(TiZrNi) and Mackay-type M(TiZrFe)

    NASA Astrophysics Data System (ADS)

    Kim, W. J.; Gibbons, P. C.; Kelton, K. F.; Yelon, W. B.

    1998-08-01

    We report the structural refinement of large-unit-cell bcc crystalline phases found in Ti-Zr-Ni and Ti-Zr-Fe alloys, which are 1/1 rational approximants of icosahedral quasicrystals in the same alloys. The structure of the stable 1/1 phase W(TiZrNi), lattice constant ao=14.317 Å, determined by a Rietveld analysis of x-ray and neutron powder diffraction data, is closely related to that of the 1/1 phases R(AlLiCu) and Bergman(AlMgZn), containing Bergman-type icosahedral clusters of atoms. Despite the similar chemistry of the 1/1 phases in Ti-Zr-Ni and Ti-Zr-Fe alloys, the 1/1 phase M(TiZrFe) contains double-shell Mackay icosahedra, like those found in the 1/1 phase α(TiCrSiO). These results provide starting structures for six-dimensional refinements of the related quasicrystals.

  11. Femtosecond observation of benzyne intermediates in a molecular beam: Bergman rearrangement in the isolated molecule.

    PubMed

    Diau, E W; Casanova, J; Roberts, J D; Zewail, A H

    2000-02-15

    In this communication, we report our femtosecond real-time observation of the dynamics for the three didehydrobenzene molecules (p-, m-, and o-benzyne) generated from 1,4-, 1,3-, and 1, 2-dibromobenzene, respectively, in a molecular beam, by using femtosecond time-resolved mass spectrometry. The time required for the first and the second C-Br bond breakage is less than 100 fs; the benzyne molecules are produced within 100 fs and then decay with a lifetime of 400 ps or more. Density functional theory and high-level ab initio calculations are also reported herein to elucidate the energetics along the reaction path. We discuss the dynamics and possible reaction mechanisms for the disappearance of benzyne intermediates. Our effort focuses on the isolated molecule dynamics of the three isomers on the femtosecond time scale.

  12. An Extended Ab Initio and Theoretical Thermodynamics Studies of the Bergman Reaction and the Energy Splitting of the Singlet Ortho-, Meta-, and Para-Benzynes

    NASA Technical Reports Server (NTRS)

    Lindh, Roland; Lee, Timothy J.; Bernhardsson, Anders; Persson, B. Joakim; Karlstroem, Gunnar; Langhoff, Stephen R. (Technical Monitor)

    1995-01-01

    The autoaromatization of (Z)-hex-3-ene-1,5-diyne to the singlet biradical para-benzyne has been reinvestigated by state of the art ab initio methods. Previous CCSD(T)/6-31G(d,p) and CASPT2[0]/ANO[C(5s4p2d1f)/H(3s2p)] calculations estimated the the reaction heat at 298 K to be 8-10 and 4.9 plus or minus 3.2 kcal/mol, respectively. Recent NO- and oxygen-dependent trapping experiments and collision-induced dissociation threshold energy experiments estimate the heat of reaction to be 8.5 plus or minus 1.0 at 470 K (recomputed to 9.5 plus or minus 1.0 at 298 K) and 8.4 plus or minus 3.0 kcal/mol at 298 K, respectively. New theoretical estimates at 298 K predict the values at the basis set limit for the CCSD(T) and CASPT2(g1) methods to be 12.7 plus or minus 2.0 and 5.4 plus or minus 2.0 kcal/mol, respectively. The experimentally predicted electronic contribution to the heat of activation is 28.6 kcal/mol. This can be compared with 25.5 and 29.8 kcal/mol from the CASPT2[g1] and the CCSD(T) methods, respectively. The new study has in particular improved on the one-particle basis set for the CCSD(T) method as compared to earlier studies. For the CASPT2 investigation the better suited CASPT2[g1] approximation is utilized. The original CASPT2 method, CASPT2[0], systematically favors open shell systems relative to closed shell systems. This was previously corrected empirically. The study shows that the energy difference between CCSD(T) and CASPT2[g1] at the basis set limit is estimated to be 7 plus or minus 2 kcal/mol. The study also demonstrates that the estimated heat of reaction is very sensitive to the quality of the basis set.

  13. Understanding Film as Process of Change: A Metalanguage for the Study of Film Developed and Applied to Ingmar Bergman's "Persona" and Alan J. Pakula's "The Sterile Cuckoo."

    ERIC Educational Resources Information Center

    Koch, Christian Herbert

    This study develops and applies a way of talking about that transformation or change occurring in the mind of a film viewer as he views a film. This articulation is expressed in a metalanguage constructed along parameters of a game situation. The terminology employed in the articulation is derived from contemporary French structuralism and…

  14. 78 FR 10251 - Qualification of Drivers; Exemption Applications; Vision

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-13

    ... System (FDMS) published in the Federal Register on December 29, 2010 (75 FR 82132), or you may visit http://www.gpo.gov/fdsys/pkg/FR-2010-12-29/pdf/2010-32876.pdf . FOR FURTHER INFORMATION CONTACT: Elaine M.... Qualifications of Applicants Michael L. Bergman Mr. Bergman, age 56, has a prosthetic right eye due to...

  15. Open Wilson lines and chiral condensates in thermal holographic QCD

    SciTech Connect

    Argyres, Philip C.; Edalati, Mohammad; Leigh, Robert G.; Vazquez-Poritz, Justin F.

    2009-02-15

    We investigate various aspects of a proposal by Aharony and Kutasov [O. Aharony and D. Kutasov, Phys. Rev. D 78, 026005 (2008).] for the gravity dual of an open Wilson line in the Sakai-Sugimoto model or its noncompact version. In particular, we use their proposal to determine the effect of finite temperature, as well as background electric and magnetic fields, on the chiral symmetry breaking order parameter. We also generalize their prescription to more complicated worldsheets and identify the operators dual to such worldsheets.

  16. The Use of Descriptors with Exemplar and Model Answers to Improve Quality of Students' Narrative Writing in English French and Arabic

    ERIC Educational Resources Information Center

    Somba, Anne W.; Obura, Ger; Njuguna, Margaret; Itevete, Boniface; Mulwa, Jones; Wandera, Nooh

    2015-01-01

    The importance of writing skills in enhancing student performance in language exams and even other subject areas is widely acknowledged. At Jaffery secondary, the approach to the teaching of writing has generally been to use three approaches: product-based approach with focus on what the students composed; process-based approach that is focused on…

  17. Proceedings of the Conference of the International Group for the Psychology of Mathematics Education (PME) (24th, Hiroshima, Japan, July 23-27, 2000), Volume 2.

    ERIC Educational Resources Information Center

    Nakahara, Tadao, Ed.; Koyama, Masataka, Ed.

    The second volume of the 24th annual conference of the International Group for the Psychology of Mathematics Education contains full research report papers. Papers include: (1) "What you see is what you get: The influence of visualization on the perception of data structures" (Dan Aharoni); (2) "Exploring the transparency of graphs and graphing"…

  18. Proceedings of the Conference of the International Group for the Psychology of Mathematics Education (21st, Lahti, Finland, July 14-19, 1997). Volume 2.

    ERIC Educational Resources Information Center

    Pehkonen, Erkki, Ed.

    The second volume of the proceedings of 21st annual meeting of the International Group for the Psychology of Mathematics Education contains the following papers: (1) "The Dilemma of Transparency: Seeing and Seeing through Talk in the Mathematics Classroom" (J. Adler); (2) "Abstraction is Hard in Computer-Science Too" (D. Aharoni and U. Leron); (3)…

  19. Test of crossover scaling in the two-dimensional random-field Ising model

    NASA Astrophysics Data System (ADS)

    Binder, K.

    1984-05-01

    The random-field-induced rounding of the specific-heat singularity observed in transfer-matrix calculations of two-dimensional Ising models by Morgenstern, Binder, and Hornreich is interpreted in terms of the Fishman-Aharony scaling theory. Results qualitatively similar to recent experimental work on Rb2Co0.85Mg0.15F4 are obtained.

  20. Reconstruction of Bulk Operators within the Entanglement Wedge in Gauge-Gravity Duality.

    PubMed

    Dong, Xi; Harlow, Daniel; Wall, Aron C

    2016-07-01

    In this Letter we prove a simple theorem in quantum information theory, which implies that bulk operators in the anti-de Sitter/conformal field theory (AdS/CFT) correspondence can be reconstructed as CFT operators in a spatial subregion A, provided that they lie in its entanglement wedge. This is an improvement on existing reconstruction methods, which have at most succeeded in the smaller causal wedge. The proof is a combination of the recent work of Jafferis, Lewkowycz, Maldacena, and Suh on the quantum relative entropy of a CFT subregion with earlier ideas interpreting the correspondence as a quantum error correcting code. PMID:27447499

  1. Reconstruction of Bulk Operators within the Entanglement Wedge in Gauge-Gravity Duality.

    PubMed

    Dong, Xi; Harlow, Daniel; Wall, Aron C

    2016-07-01

    In this Letter we prove a simple theorem in quantum information theory, which implies that bulk operators in the anti-de Sitter/conformal field theory (AdS/CFT) correspondence can be reconstructed as CFT operators in a spatial subregion A, provided that they lie in its entanglement wedge. This is an improvement on existing reconstruction methods, which have at most succeeded in the smaller causal wedge. The proof is a combination of the recent work of Jafferis, Lewkowycz, Maldacena, and Suh on the quantum relative entropy of a CFT subregion with earlier ideas interpreting the correspondence as a quantum error correcting code.

  2. Do Students Learn More from a Flip? An Exploration of the Efficacy of Flipped and Traditional Lessons

    ERIC Educational Resources Information Center

    DeSantis, Joshua; Van Curen, Rebecca; Putsch, Jake; Metzger, Justin

    2015-01-01

    Flipped lesson planning, as popularized by Bergman & Sams (2012a), has been viewed by many as a revolutionary pedagogy, tailor-made for the twenty-first century classroom. Enthusiasm for flipped lesson planning has out-paced the collection of data that might determine its effectiveness. This paper presents the results of a study that compared…

  3. Proceedings of the Annual Conference of the International Association of School LIbrarianship (19th, Umea, Sweden, July 8-12, 1990).

    ERIC Educational Resources Information Center

    International Association of School Librarianship, Kalamazoo, MI.

    This conference report contains 32 presented papers: "Talking Books for Children in Sweden in Libraries and Schools" (L. Bergman); "At-Risk Students: How Do School (Library) Systems Respond?" (G. R. Brown); "Providing School Library Services to Immigrant Populations" (K. W. Craver); "Bibliographic Aids for School Libraries" (K. Darling); "The…

  4. Synthesis and biological activity of new arenediyne-linked isoxazolidines.

    PubMed

    Romeo, Roberto; Navarra, Michele; Giofrè, Salvatore V; Carnovale, Caterina; Cirmi, Santa; Lanza, Giuseppe; Chiacchio, Maria A

    2014-07-01

    Arenediyne-isoxazolidine conjugates have been synthesized as a new scaffold for the development of bioactive mimics. Some of the synthesized compounds are endowed with antiproliferative activity against three human cancer cell lines. Their thermal reactivity suggests that the biological activity probably could not be linked to the Bergman cyclization.

  5. Updating the Trainability Tests Literature on Black-White Subgroup Differences and Reconsidering Criterion-Related Validity

    ERIC Educational Resources Information Center

    Roth, Philip L.; Buster, Maury A.; Bobko, Philip

    2011-01-01

    A number of applied psychologists have suggested that trainability test Black-White ethnic group differences are low or relatively low (e.g., Siegel & Bergman, 1975), though data are scarce. Likewise, there are relatively few estimates of criterion-related validity for trainability tests predicting job performance (cf. Robertson & Downs, 1989). We…

  6. Supporting Academic Literacies: University Teachers in Collaboration for Change

    ERIC Educational Resources Information Center

    Bergman, Lotta

    2016-01-01

    This article deals with an action research project, where a group of university teachers from different disciplines reflected on and gradually extended their knowledge about how to support students' academic literacy development. The project was conducted within a "research circle" [Bergman, L. 2014. "The Research Circle as a…

  7. "The Seventh Seal."

    ERIC Educational Resources Information Center

    Palmer, Peter M.

    1969-01-01

    The significance of Bergman's "Seventh Seal" lies not in the speeches nor in the actions of the central characters but rather in the film's form, its totality created by the emotive elements of imagery and sound together with the intellectual elements of actions and words. The scene-units are related to a central motif (the opening of the seventh…

  8. 76 FR 16821 - Gregory F. Saric, M.D.; Decision and Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-25

    ... similar to that of Respondent's.'' Exceptions at 1 (citing Stuart A. Bergman, M.D., 70 FR 33193 (2005... Health Servs., 72 FR 42126 (2007) (quoting Bourne Pharmacy, Inc., 72 FR 18273, 18274 (2007) (quoting 21 U... * * * controlled substances under the laws of the State in which he practices.''); Bourne Pharmacy, 72 FR at...

  9. Home on the Wide-Open Range of Gender

    ERIC Educational Resources Information Center

    Beemyn, Genny

    2011-01-01

    Kate Bornstein and S. Bear Bergman's "Gender Outlaws: The Next Generation" is a collection of narratives written by individuals with a wide range of gender identities and expressions from around the world. The text shows how gender-nonconforming people are changing how society looks at gender. As many of the individuals who are challenging gender…

  10. Predictive accuracy in the neuroprediction of rearrest

    PubMed Central

    Aharoni, Eyal; Mallett, Joshua; Vincent, Gina M.; Harenski, Carla L.; Calhoun, Vince D.; Sinnott-Armstrong, Walter; Gazzaniga, Michael S.; Kiehl, Kent A.

    2014-01-01

    A recently published study by the present authors (Aharoni et al., 2013) reported evidence that functional changes in the anterior cingulate cortex (ACC) within a sample of 96 criminal offenders who were engaged in a Go/No-Go impulse control task significantly predicted their rearrest following release from prison. In an extended analysis, we use discrimination and calibration techniques to test the accuracy of these predictions relative to more traditional models and their ability to generalize to new observations in both full and reduced models. Modest to strong discrimination and calibration accuracy were found, providing additional support for the utility of neurobiological measures in predicting rearrest. PMID:24720689

  11. Scaling and universality in the two-dimensional Ising model with a magnetic field

    NASA Astrophysics Data System (ADS)

    Mangazeev, Vladimir V.; Dudalev, Michael Yu.; Bazhanov, Vladimir V.; Batchelor, Murray T.

    2010-06-01

    The scaling function of the two-dimensional Ising model on the square and triangular lattices is obtained numerically via Baxter’s variational corner transfer-matrix approach. The use of Aharony-Fisher nonlinear scaling variables allowed us to perform calculations sufficiently away from the critical point and to confirm all predictions of the scaling and universality hypotheses. Our results are in excellent agreement with quantum field theory calculations of Fonseca and Zamolodchikov as well as with many previously known exact and numerical calculations, including susceptibility results by Barouch, McCoy, Tracy, and Wu.

  12. Correction-to-scaling exponent for two-dimensional percolation

    SciTech Connect

    Ziff, Robert M.

    2011-02-15

    We show that the correction-to-scaling exponents in two-dimensional percolation are bounded by {Omega}{<=}72/91, {omega}=D{Omega}{<=}3/2, and {Delta}{sub 1}={nu}{omega}{<=}2, based upon Cardy's result for the crossing probability on an annulus. The upper bounds are consistent with many previous measurements of site percolation on square and triangular lattices and new measurements for bond percolation, suggesting that they are exact. They also agree with exponents for hulls proposed recently by Aharony and Asikainen, based upon results of den Nijs. A corrections scaling form evidently applicable to site percolation is also found.

  13. Multimodal imaging measures predict rearrest.

    PubMed

    Steele, Vaughn R; Claus, Eric D; Aharoni, Eyal; Vincent, Gina M; Calhoun, Vince D; Kiehl, Kent A

    2015-01-01

    Rearrest has been predicted by hemodynamic activity in the anterior cingulate cortex (ACC) during error-processing (Aharoni et al., 2013). Here, we evaluate the predictive power after adding an additional imaging modality in a subsample of 45 incarcerated males from Aharoni et al. (2013). Event-related potentials (ERPs) and hemodynamic activity were collected during a Go/NoGo response inhibition task. Neural measures of error-processing were obtained from the ACC and two ERP components, the error-related negativity (ERN/Ne) and the error positivity (Pe). Measures from the Pe and ACC differentiated individuals who were and were not subsequently rearrested. Cox regression, logistic regression, and support vector machine (SVM) neuroprediction models were calculated. Each of these models proved successful in predicting rearrest and SVM provided the strongest results. Multimodal neuroprediction SVM models with out of sample cross-validating accurately predicted rearrest (83.33%). Offenders with increased Pe amplitude and decreased ACC activation, suggesting abnormal error-processing, were at greatest risk of rearrest. PMID:26283947

  14. Multimodal imaging measures predict rearrest

    PubMed Central

    Steele, Vaughn R.; Claus, Eric D.; Aharoni, Eyal; Vincent, Gina M.; Calhoun, Vince D.; Kiehl, Kent A.

    2015-01-01

    Rearrest has been predicted by hemodynamic activity in the anterior cingulate cortex (ACC) during error-processing (Aharoni et al., 2013). Here, we evaluate the predictive power after adding an additional imaging modality in a subsample of 45 incarcerated males from Aharoni et al. (2013). Event-related potentials (ERPs) and hemodynamic activity were collected during a Go/NoGo response inhibition task. Neural measures of error-processing were obtained from the ACC and two ERP components, the error-related negativity (ERN/Ne) and the error positivity (Pe). Measures from the Pe and ACC differentiated individuals who were and were not subsequently rearrested. Cox regression, logistic regression, and support vector machine (SVM) neuroprediction models were calculated. Each of these models proved successful in predicting rearrest and SVM provided the strongest results. Multimodal neuroprediction SVM models with out of sample cross-validating accurately predicted rearrest (83.33%). Offenders with increased Pe amplitude and decreased ACC activation, suggesting abnormal error-processing, were at greatest risk of rearrest. PMID:26283947

  15. Singlet benzyne thermochemistry: a CASPT2 study of the enthalpies of formation

    NASA Astrophysics Data System (ADS)

    Lindh, Roland; Schütz, Martin

    1996-08-01

    The enthalpies of formation for singlet benzynes were examined at the CASPT2 (second order perturbation theory, based on a complete active space SCF reference function) level of theory. The study employed isodesmic reactions in order to minimize the influence of systematic errors of the method. The results obtained for m- and p-benzyne were found to dispute earlier experimentally deduced values; a discrepancy of about 5 kcal/mol was observed. As a consequence, the enthalpy of reaction of the so called Bergman reaction, deduced previously from the experimental enthalpy of formation of p-benzyne, seems to be overestimated by about 5 kcal/mol. Furthermore, it was observed that the CCSD(T) method (coupled cluster singles and doubles with a perturbatative estimate of the triples contribution) is inappropriate for a balanced treatment of the Bergman reaction, due to the extensive differences in the electronic structures of the two reactants.

  16. Introduction to the Maxwell Garnett approximation: tutorial.

    PubMed

    Markel, Vadim A

    2016-07-01

    This tutorial is devoted to the Maxwell Garnett approximation and related theories. Topics covered in this first, introductory part of the tutorial include the Lorentz local field correction, the Clausius-Mossotti relation and its role in the modern numerical technique known as the discrete dipole approximation, the Maxwell Garnett mixing formula for isotropic and anisotropic media, multicomponent mixtures and the Bruggeman equation, the concept of smooth field, and Wiener and Bergman-Milton bounds. PMID:27409680

  17. A Sodium-Containing Quasicrystal: Using Gold To Enhance Sodium's Covalency in Intermetallic Compounds

    SciTech Connect

    Smetana, Volodymyr; Lin, Qisheng; Pratt, Daniel K.; Kreyssig, Andreas; Ramazanoglu, Mehmet; Corbett, John D.; Goldman, Alan I.; Miller, Gordon J.

    2013-09-26

    Gold macht stabil: Na13Au12Ga15, ein natriumhaltiges thermodynamisch stabiles quasikristallines Material, wurde bei einer systematischen Studie des polaren Na-Au-Ga-Intermetallsystems entdeckt. Sein Elektron/Atom-Verhältnis von 1.75 ist für Bergman-Ikosaederphasen extrem klein, doch der substanzielle Au-Anteil sorgt für eine Hume-Rothery-Stabilisierung und neuartige polar-kovalente Na-Au-Wechselwirkungen.

  18. Phytochemical diversity of cranberry (Vaccinium macrocarpon Aiton) cultivars by anthocyanin determination and metabolomic profiling with chemometric analysis.

    PubMed

    Brown, Paula N; Murch, Susan J; Shipley, Paul

    2012-01-11

    Originally native to the eastern United States, American cranberry ( Vaccinium macrocarpon Aiton, family Ericaceae) cultivation of native and hybrid varieties has spread across North America. Herein is reported the phytochemical diversity of five cranberry cultivars (Stevens, Ben Lear, Bergman, Pilgrim, and GH1) collected in the Greater Vancouver Regional District, by anthocyanin content and UPLC-TOF-MS metabolomic profiling. The anthocyanin content for biological replicates (n = 5) was determined as 7.98 ± 5.83, Ben Lear; 7.02 ± 1.75, Bergman; 6.05 ± 2.51, GH1; 3.28 ± 1.88, Pilgrim; and 2.81 ± 0.81, Stevens. Using subtractive metabonomic algorithms 6481 compounds were found conserved across all varietals, with 136 (Ben Lear), 84 (Bergman), 91 (GH1), 128 (Pilgrim), and 165 (Stevens) unique compounds observed. Principal component analysis (PCA) did not differentiate varieties, whereas partial least-squares discriminate analysis (PLS-DA) exhibited clustering patterns. Univariate statistical approaches were applied to the data set, establishing significance of values and assessing quality of the models. Metabolomic profiling with chemometric analysis proved to be useful for characterizing metabonomic changes across cranberry varieties.

  19. Poincare-type metrics and their ∂ estimates on pseudoconvex domains

    NASA Astrophysics Data System (ADS)

    Edgren, Neal

    The Bergman kernel and its associated metric are fundamental to the study of complex analysis. However, it is very difficult to compute these objects on domains whose boundaries are not described in terms of computationally simple functions, or on asymmetric domains. The Bergman metric on the unit ball in Cn is given by the complex Hessian of the function --(n + 1) log(1 --|z| 2). As r(z) = |z|2 -- 1 is a defining function for the unit ball, the Bergman metric is thus described by a very simple potential function and, after some work, we can generalize this idea to bounded pseudoconvex domains with at least C2 boundary. We recall that on such domains Ω , defining functions can be modified to obtain a bounded plurisubharmonic exhaustion function r on Ω , and define a Poincare-type metric to be the complex Hessian of --log(--r). The main results we present on the geometry of Poincare-type metrics are contained in Chapter 2. It turns out that they are all complete, much like the Bergman metric on domains with smooth boundary. It would be quite interesting to study the geodesics of these metrics, but we have not included that in this dissertation. On strongly pseudoconvex domains with C infinity boundary, we show that these metrics are quasi-isometric under biholomorphisms. This is a partial generalization of the elementary fact that all biholomorphisms are isometries of the Bergman metric, regardless of conditions on the domain. The remaining three chapters deal with ∂ theory and estimates related to Poincaretype metrics. We first explore the Hodge theory of Poincare-type metrics, concluding that they have trivial L2 Dolbeault cohomology except on (p, q)-forms where p+q = n. We then examine the twisted Cauchy-Riemann complex and prove an estimate on solutions to a ∂ problem appropriate for this setting. We finish the dissertation by discussing an application of this estimate to the old problem of constructing functions on the disk which do not extend past any

  20. Asymptotic dependence of the relaxation time of the magnetization of a ferromagnetic particle on the anisotropy of the particle

    NASA Astrophysics Data System (ADS)

    Scully, C. N.; Cregg, P. J.; Crothers, D. S. F.

    1992-01-01

    It is known that the direction of the magnetization vector of very fine single-domain ferromagnetic particles fluctuates under the influence of thermal agitation. Perturbation theory is applied rigorously to a singular integral equation to derive an asymptotic formula for the relaxation time of the magnetization, for the case of uniaxial anisotropy and an applied magnetic field. The result agrees with that of Brown [Phys. Rev. 130, 1677 (1963)] as described succinctly by Aharoni [Phys. Rev. 177, 793 (1969)]. It should be emphasized that both Gilbert's equation and the earlier Landau-Lifshitz equation are merely phenomenological equations, which are used to explain the time decay of the average magnetization. Brown suggested that the Gilbert equation should be augmented by a white-noise driving term in order to explain the effect of thermal fluctuations of the surroundings on the magnetization.

  1. Blood glucose regulation in diabetics. A flatness based nonlinear control simulation study

    NASA Astrophysics Data System (ADS)

    Cocha, Guillermo; Podestá, Melina; Mazzadi, Alejandro; Amorena, Carlos; D'Atellis, Carlos

    2016-04-01

    Flat systems are a generalization of linear systems, but the techniques used for controlling flat systems are much different than many of the existing techniques for linear systems. In this paper we present the flatness-based control of blood glucose regulation in human system. A non-near model, he Bergman Minimal Model, is used o represent he dynamics of blood regulation in humans and because of the flatness property, he system variables can be expressed as functions of he at output and heir time derivatives and a control aw developed.

  2. Students Share Their Research at Student Poster Day | Poster

    Cancer.gov

    Students Share Their Research at Student Poster Day  By Ashley DeVine, Staff Writer More than 50 Werner H. Kirsten student interns and college interns presented their research at Summer Student Poster Day on August 6 in the Building 549 lobby.  Joseph Bergman, a high school intern in the Center for Cancer Research Nanobiology Laboratory, participated in the event “for the opportunity to present my summer research. It allowed me to meet people and get the experience of sharing and explaining my work.”

  3. [The virtuous doctor in cinema: the final examination].

    PubMed

    Figueroa, Gustavo

    2014-10-01

    The virtuous doctor has subscribed an oath and by subscribing to this solemn promise, he is committed to live in accordance with the purposes, obligations and virtues established in the medical profession. Cinematic art has shown only a superficial interest in complex aspects of medical profession. An exception is Ingmar Bergman's film "Wild Strawberries", where Professor Isak Borg, a widowed 76-year-old physician, is to be awarded the Doctor Jubilaris degree, 50 years after he received his doctorate at Lund University. During the trip, Isak is forced by a nightmare to reevaluate his professional life as not being a virtuous doctor.

  4. Quasicrystal-Crystal Transformation in Zn-Mg-Rare-Earth Alloys

    NASA Astrophysics Data System (ADS)

    Abe, Eiji; Tsai, An Pang

    1999-07-01

    We report a reversible phase transformation between the icosahedral Zn-Mg-rare-earth(RE) quasicrystal and the hexagonal crystal being not composed of any giant icosahedral atomic cluster. This clearly shows that the large atomic cluster is not an essential atomic configuration for quasicrystal formation. A structural unit of the Zn-Mg-RE icosahedral quasicrystal is suggested to be not an icosahedral atomic cluster such as the Mackay or Bergman type which have been successfully used for the structural description of the Al-based icosahedral quasicrystalline phases.

  5. Stability comparison of several icosahedral structure units of Al-Cr alloys

    NASA Astrophysics Data System (ADS)

    Liu, Da; Wang, Renhui; Ye, Yiying

    1991-02-01

    Total energies for three types of icosahedral structure units of Al-Cr alloys have been calculated based on the embedded-atom method. The results show that the most stable structure unit is the small icosahedron with a Cr atom at its center, and the hypothetical structures based on the Mackay icosahedron and Bergman rhombic triacontahedron possess higher energies compared with those of the face-centered-cubic-solid solutions and the mechanical mixtures of pure Al and Cr crystals. These results are found to be consistent with experiment.

  6. Size-tunable polymeric nanoreactors for one-pot synthesis and encapsulation of quantum dots.

    PubMed

    Qian, Guannan; Zhu, Benchuan; Wang, Youfu; Deng, Sheng; Hu, Aiguo

    2012-08-28

    Hydrophilic polymeric nanoparticles are synthesized through a Bergman cyclization- mediated intramolecular chain collapse of structurally well-defined linear polymers, and then used as size-tunable nanoreactors to fabricate and encapsulate quantum dots in a one-pot reaction. Crystalline quantum dots are formed in all of these nanoreactors and visualized by transmission electron microscopy. Smaller nanoreactors produce one quantum dot each while larger nanoreactors form a number, resulting in fluorescence quenching. By controlling the molecular weight of the linear polymer precursor, a variable number of nanocrystals are fabricated and assembled in a single nanoreactor.

  7. Development of ideas on renovascular hypertension.

    PubMed

    Peart, S

    2000-09-01

    Stephen Hales was the first to measure blood pressure directly in the horse (1733), and the definitive studies on human nephrins by Richard Bright followed much later (1836). The relation between high blood pressure and renal disease was established by Mahomed (1872). The discovery of renin and its possible link with Bright's disease was made by Tigerstedt and Bergman (1898), but only the experimental production of renal hypertension by Goldblatt and his colleagues (1934) led to the delineation of the role of the kidney in human hypertension by a wide variety of methods. PMID:11022890

  8. Homogenization of the Three-dimensional Hall Effect and Change of Sign of the Hall Coefficient

    NASA Astrophysics Data System (ADS)

    Briane, Marc; Milton, Graeme W.

    2009-09-01

    The notion of a Hall matrix associated with a possibly anisotropic conducting material in the presence of a small magnetic field is introduced. Then, for any material having a microstructure we prove a general homogenization result satisfied by the Hall matrix in the framework of the H-convergence of Murat-Tartar. Extending a result of Bergman, we show that the Hall matrix can be computed from the corrector associated with the homogenization problem when no magnetic field is present. Finally, we give an example of a microstructure for which the Hall matrix is positive isotropic almost everywhere, while the homogenized Hall matrix is negative isotropic.

  9. Orientation relationship between the T structure and the icosahedral quasicrystal in the Zn-Mg-Al alloy system

    NASA Astrophysics Data System (ADS)

    Nakayama, Kei; Watanabe, Junya; Koyama, Yasumasa

    2016-08-01

    To understand the crystallographic relation between the Bergman-type icosahedral quasicrystal and its approximant-T structure, we have investigated the crystallographic features of prepared Zn-Mg-Al alloy samples, mainly by transmission electron microscopy. It was found that there existed three kinds of regions: that is, C14-Laves, approximant-T, and icosahedral-quasicrystal regions, in Zn-Mg-Al alloy samples with the composition of Zn-36at.%Mg-9at.%Al. Among these regions, in particular, we tried to determine an orientation relationship between neighboring icosahedral-quasicrystal and approximant-T regions. Based on the determined relationship, for instance, four threefold rotatory-inversion axes in the T structure were found to be parallel to four of ten threefold rotatory-inversion axes in the icosahedral quasicrystal. It was thus understood that the atomic arrangements of the Bergman-type icosahedral quasicrystal and its approximant-T structure are likely to resemble each other.

  10. Titanium-based icosahedral quasicrystals and approximants: Phase formation, cluster structure, and hydrogenation

    NASA Astrophysics Data System (ADS)

    Majzoub, Eric Hish

    Equilibrium phase formation is reported for ternary Ti-Zr-Ni alloys near the icosahedral phase (i-phase) forming composition. The i-phase forms over a small compositional range from a high-temperature equilibrium phase mixture of the Laves and alpha(Ti/Zr) solid solution phases. Additions of small amounts of Pb, 1--2 at. %, are demonstrated to substantially effect the equilibrium phase formation and extend the stability of the i-phase to nearly 700°C. An electrochemical method was used to hydrogenate Ti-based quasicrystals and their crystal approximants. This technique gives a consistently high hydrogen to metal atom ratio of 1.9, without crystal hydride formation in the quasicrystal. Nuclear Magnetic Resonance (NMR) measurements of the hydrogen dipole-dipole interaction were made using hydrided i-phase samples. Comparisons with simulations based on hydrogen filling of the approximant-phase tetrahedral interstitials reveals that any filling order is consistent with the experimental data. Studies of the atomic structure of hydrided and unhydrided i-TiZrNi quasicrystal and its approximant are reported. We construct constrained icosahedral glass models using Bergman and Mackay clusters to describe the i-phase in Ti-Zr-Ni and Ti-TM-Si-O. A comparison of simulated and experimental diffraction reveals that, the Bergman and Mackay clusters are the fundamental clusters in i-TiZrNi and i-TiMnSiO, respectively.

  11. Correlations between dynamics and atomic structures in Cu64.5Zr35.5 metallic glass

    NASA Astrophysics Data System (ADS)

    Wang, C. Z.; Zhang, Y.; Zhang, F.; Mendelev, M. I.; Kramer, M. J.; Ho, K. M.

    2015-03-01

    The atomic structure of Cu-Zr metallic glasses (MGs) has been widely accepted to be heterogeneous and dominated by icosahedral short range order (ISRO). However, the correlations between dynamics and atomic structures in Cu-Zr MGs remain an enigma. Using molecular dynamics (MD) simulations, we investigated the correlations between dynamics and atomic structures in Cu64.5Zr35.5 MG. The atomic structures are characterized using ISRO and the Bergman-type medium range order (BMRO). The simulation and analysis results show that the majority of the mobile atoms are not involved in ISRO or BMRO, indicating that the dynamical heterogeneity has a strong correlation to structural heterogeneity. Moreover, we found that the localized soft vibration modes below 1.0 THz are mostly concentrated on the mobile atoms. The diffusion was studied using the atomic trajectory collected in an extended time interval of 1.2 μs at 700 K in MD simulations. It was found that the long range diffusion in MGs is highly heterogeneous, which is confined to the liquid-like regions and strongly avoids the ISRO and the Bergman-type MRO. All These results clearly demonstrate strong correlations between dynamics (in terms of dynamical heterogeneity and diffusion) and atomic structures in Cu64.5Zr35.5 MGs. This work was supported by the U.S. Department of Energy, Basic Energy Sciences, Division of Materials Science and Engineering under the Contract No. DE-AC02-07CH11358.

  12. Response to ``Comment on `Slow Debye-type peak observed in the dielectric response of polyalcohols' '' [J. Chem. Phys. 134, 037101 (2011)

    NASA Astrophysics Data System (ADS)

    Bergman, R.; Jansson, H.; Swenson, J.

    2011-01-01

    In our recent article [R. Bergman et al., J. Chem. Phys. 132, 044504 (2010)] we investigated some polyalcohols, i.e., glycerol, xylitol, and sorbitol by dielectric spectroscopy. In the study, a low-frequency peak of Debye character that normally is hidden by the large low-frequency dispersion due to conductivity was revealed by analyzing the real part of the permittivity and by using a thin Teflon film to suppress the low-frequency dispersion. We agree with the comment by Paluch et al. [J. Chem. Phys. 134, 037101 (2011)] that the Teflon film setup will indeed create a peak due to the dc conductivity. However, due to the fact that the location of the peak was almost identical in measurement with and without Teflon, we unfortunately mainly showed the data measured with Teflon, despite that it could also be observed in the real part of the permittivity without using the Teflon setup, as shown in our original article [R. Bergman et al., J. Chem. Phys. 132, 044504 (2010)]. Here, we show that the low-frequency peak of Debye character can also be observed by subtracting the dc conductivity. Furthermore, we show that the modulus representation used in Paluch et al. [J. Chem. Phys. 134, 037101 (2011).] is also not suitable for detecting processes hidden by the conductivity.

  13. Order Parameters and Phase Diagram of Multiferroic RMn2O5

    NASA Astrophysics Data System (ADS)

    Harris, A. Brooks

    2009-03-01

    ρ τ λ σ ξ χ 1 2 1 3 1 4 3 4 Recently there has been great interest in systems which display phase transitions at which incommensurate magnetic order and a spontaneous polarization develop simultaneously. Perhaps the most puzzling and seemingly complicated behavior occurs in the series of compounds RMn2O5, where R=Y, Ho, Er, Tb, Tm, and Dy. (For references to experimental data, see [1].) The sequence of magnetoelectric phases of the type I systems R=Tb, Ho, and Dy is slightly different from that of the type II systems R= Y, Tm, and Er. At about 45K both types develop essentially collinear modulated magnetic order into a ``high-temperature ordered" (HTO) phase with a wave vector q = (1/2-δ, 0, 1/4 + ɛ) where δ and |ɛ| are of order 0.01 and the spontaneous polarization is zero. There is a lower-temperature phase transition to a ferroelectric phase in which transverse magnetic order appears and produces a magnetic spiral with δ=ɛ=0. In type I systems, this transition occurs directly from the HTO phase, whereas for type II systems, there is an intervening ferroelectric phase in which ɛ=0, but δ remains nonzero. %At low (<10K) temperature the classification into types I and II %breaks down and each system requires its own specific description. I will discuss a Landau free energy[1] which allows both type I and type II sequences of phase transitions. This theory is couched in terms of the uniform polarization vector P and two complex-valued magnetic order parameters σ1(q) and σ2(q) whose symmetry follows from the magnetic structure analyses.[2] The magnetoelectric coupling and the competition between commensurate and incommensurate phases are analyzed. [4pt] [1] A. B. Harris, A. Aharony, and O. Entin-Wohlman, Phys. Rev. Lett. 100, 217202 (2008) and J. Phys. Condens. Mat. 20, 434202 (2008). [0pt] [2] A. B. Harris, Phys. Rev. 76, 054447 (2007); A. B. Harris, M. Kenzelmann, A. Aharony, and O. Entin-Wohlman, Phys. Rev. B 78, 014407 (2008).

  14. Field dependence of the magnetic order in Co3V2O8

    NASA Astrophysics Data System (ADS)

    Chen, Ying; Lynn, J. W.; Huang, Q.; Woodward, F. M.; Yildirim, T.; Lawes, G.; Ramirez, A. P.; Rogado, N.; Cava, R. J.; Aharony, A.; Entin-Wohlman, O.; Harris, A. B.

    2007-03-01

    Co3V2O8 (CVO) has a geometrically frustrated magnetic lattice, a Kagomé staircase. In zero field [1], CVO initially orders magnetically at 11.3 K into an incommensurate phase, with wave vector k = (0,δ,0) with δ = 0.55. δ decreases monotonically with decreasing temperature. It locks into a commensurate antiferromagnetic value of 12 and 13 before the ferromagnetic ground state (&=tilde; 0) is revealed at 6.2 K. The spin direction for all spins is along the a axis. A theory based on a minimal Ising model with competing exchange interactions can explain the basic features of the magnetic ordering. The application of magnetic field along the a axis strongly affects all of the phases. In particular, the ferromagnetic state is suppressed in favor of the δ=0.5 antiferromagnetic state. [1] Y. Chen, J. W. Lynn, Q. Huang, F. M. Woodward, T. Yildirim, G. Lawes, A. P. Ramirez, N. Rogado, R. J. Cava, A. Aharony, O. Entin-Wohlman, and A. B. Harris, Phys. Rev. B 74, 014430 (2006).

  15. Ultrafast and Quantum Nanoplasmonics: SPASER and Control

    NASA Astrophysics Data System (ADS)

    Stockman, Mark I.

    2009-03-01

    Nanoplasmonics is presently experiencing a period of unprecedented growth and has numerous applications. These include sensing and detection of minute amount of chemical and biological objects for biomedicine and defense [1], near-field scanning optical microscopy [2], immunological tests, labels for biomedical research, nanoantennas for efficient coupling of light to semiconductor devices, etc. Nanoplasmonics still greatly needs active elements to generate optical energy on the nanoscale and serve as amplifiers. We have proposed a quantum nanoplasmonic generator and amplifier of the local optical fields, SPASER [surface plasmon amplification by stimulated emission (of radiation)]. [3-5]. A SPASER is analogous to laser except that light (photons) is replaced by local optical fields (surface plasmons). This is responsible for the principal difference: laser cavity must support photonic modes and its size is on order or much greater than the optical wavelength, cf. [6]. In contrast, the surface plasmons in the spaser are purely electric oscillations whose localization size is nanometric. SPASER will transform nanoplasmonics the same way as the laser transformed optics. In particular nanoplasmonic processors working at THz operation rates will become possible. Another important area is the active control of nanoplasmonic phenomena. One approach to it is coherent control, where a shaped optical pulse dynamically, on the femtosecond scale controls the nanoscale distribution of local fields [7-12]. References [1] J. N. Anker et al., Nature Materials 7, 442 (2008). [2] L. Novotny, and B. Hecht, Principles of nano-optics (Cambridge University Press, Cambridge, New York, 2006). [3] D. J. Bergman, and M. I. Stockman, Phys. Rev. Lett. 90, 027402 (2003). [4] K. Li et al., Phys. Rev. B 71, 115409 (2005). [5] M. I. Stockman, Nature Photonics 2, 327 (2008). [6] M. T. Hill et al., Nature Photonics 1, 589 (2007). [7] M. I. Stockman, S. V. Faleev, and D. J. Bergman, Phys. Rev. Lett

  16. Na{sub 8}Au{sub 9.8(4)}Ga{sub 7.2} and Na{sub 17}Au{sub 5.87(2)}Ga{sub 46.63}: The diversity of pseudo 5-fold symmetries in the Na–Au–Ga system

    SciTech Connect

    Smetana, Volodymyr; Corbett, John D. Miller, Gordon J.

    2013-11-15

    The Na-rich part (∼30% Na) of the Na–Au–Ga system between NaAu{sub 2}, NaGa{sub 4}, and Na{sub 22}Ga{sub 39} has been found to contain the ternary phases Na{sub 8}Au{sub 9.8(4)}Ga{sub 7.2} (I) and Na{sub 17}Au{sub 5.87(2)}Ga{sub 46.63} (II), according to the results of single crystal X-ray diffraction measurements. I is orthorhombic, Cmcm, a=5.3040(1), b=24.519(5), c=14.573(3) Å, and contains a network of clusters with local 5-fold symmetry along the a-axis. Such clusters are frequent building units in decagonal quasicrystals and their approximants. II is rhombohedral, R3{sup ¯}m, a=16.325(2), c=35.242(7) Å, and contains building blocks that are structurally identical to the Bergman-type clusters as well as fused icosahedral units known with active metals, triels and late transition elements. II also contains a polycationic network with elements of the clathrate V type structure. Tight-binding electronic structure calculations using linear muffin–tin-orbital (LMTO) methods on idealized models of I and II indicate that both compounds are metallic with evident pseudogaps at the corresponding Fermi levels. The overall Hamilton bond populations are generally dominated by Au–Ga and Au–Au bonds in I and by Ga–Ga bonds in II; moreover, the Na–Au and Na–Ga contributions in I are unexpectedly large, ∼20% of the total. A similar involvement of sodium in covalent bonding has also been found in the electron-richer i-Na{sub 13}Au{sub 12}Ga{sub 15} quasicrystal approximant. - Graphical abstract: Multiply-endohedral Bergman-related clusters in the structure of Na{sub 17}Au{sub 5.9(1)}Ga{sub 46.6.} Display Omitted - Highlights: • Two new compounds with the local 5-fold symmetry have been investigated. • Na{sub 8}Au{sub 9.8(4)}Ga{sub 7.2} is an orthorhombic approximant of the Na{sub 13}Au{sub 12}Ga{sub 15} quasicrystal. • Na{sub 17}Au{sub 5.87(2)}Ga{sub 46.63} represents a rhombohedral distortion of the Bergman-type phases.

  17. Experimental Investigation of the Kinetics of a Ruthenium-Catalyzed Deconstruction of Lignin Model Compounds

    SciTech Connect

    Bu, L.; Nimlos, M. R.; Shirts, M. R.; Himmel, M. E.; Crowley, M. F.; Beckham, G. T.

    2012-01-01

    Lignin is a major component of plant cell walls that is typically underutilized in selective conversion strategies for renewable fuels and chemicals. The mechanisms by which thermal and catalytic treatments deconstruct lignin remain elusive. In this work, we have investigated the kinetics of the catalytic deconstruction of lignin model compounds using a ruthenium catalyst reported by Bergman et al. in 2010. A series of investigations using NMR spectroscopy and GC/MS will be presented. In addition, we propose detailed mechanisms for lignin depolymerization with ruthenium catalysts. We have also used DFT to compute transition state geometries of catalytic cycle intermediates and compare the values determined computationally with those observed experimentally. Ultimately, our objective is to apply our methods to the design of new homogeneous and heterogeneous catalysts for the effective deconstruction and valorization of lignin.

  18. Commentary: On the Importance of Early Life Cognitive Abilities in Shaping Later Life Outcomes.

    PubMed

    Hofer, Scott M; Clouston, Sean

    2014-01-01

    Early life cognitive ability is likely to be dynamically related to life course factors including educational attainment, occupational outcomes, health behaviors, activities, health, and subsequent cognitive health. Disentangling the selective and causal processes contributing to cognitive functioning across the lifespan is challenging and requires long-term investments in longitudinal data. We discuss results from several analyses using data from the Individual Development and Adaptation longitudinal research program (Bergman, 2000; Magnusson, 1988) that provide fresh insights into the relation of early life cognition, particularly high levels of cognitive capabilities, to educational achievement, emotional adjustment, and career success. These papers and the longitudinal data provide a remarkable window into the development and impacts of cognition, and high cognitive functioning, on a variety of important life outcomes that we hope will continue to inform us about additional outcomes in middle life, transition to retirement, and cognition and health in later years and to robustly examine how the early years matter across the whole lifespan.

  19. Ortho-, meta-, and para-benzyne. A comparative CCSD (T) investigation

    NASA Astrophysics Data System (ADS)

    Kraka, Elfi; Cremer, Dieter

    1993-12-01

    Geometries and energies of ortho-benzyne ( 1), mata-benzyne ( 2), and para-benzyne ( 3) have been calculated at the CCSD (T), GVB, GVB-LSDC, and MBPT (2) levels of theory employing the 6-31G(d, p) basis. Calculations suggest relative energies of O, 13.7, and 25.3 kcal/mol, respectively, and Δ H0f(298) values of 110.8, 123.9, and 135.7 kcal/mol for 1, 2, and 3. With the Δ H0f(298) value of 3, the reaction enthalpy Δ RH(298) and the activation enthalpy Δ H#(298) for the Bergman cyclization of (Z)-hexa-1,5-diy -ene to 3 are calculated to be 9.1 and 28.5 kcal/mol.

  20. Magnetic properties and aromaticity of o-, m-, and p-benzyne.

    PubMed

    De Proft, Frank; von Ragué Schleyer, Paul; van Lenthe, Joop H; Stahl, Frank; Geerlings, Paul

    2002-08-01

    The relative aromaticities of the three singlet benzyne isomers, 1,2-, 1,3-, and 1,4-didehydrobenzenes have been evaluated with a series of aromaticity indicators, including magnetic susceptibility anisotropies and exaltations, nucleus-independent chemical shifts (NICS), and aromatic stabilization energies (all evaluated at the DFT level), as well as valence-bond Pauling resonance energies. Most of the criteria point to the o-benzyneBergman cyclization of (Z)-hexa-1,5-diyn-3-ene which yields p-benzyne. Dissected NICS calculations reveal an aromatic transition state with a larger total NICS but a smaller NICS(pi) component and thus lower aromaticity than benzene.

  1. Case report: accessory head of the deep forearm flexors

    PubMed Central

    JONES, M.; ABRAHAMS, P. H.; SAÑUDO, J. R.

    1997-01-01

    In 1813 Gantzer described 2 accessory muscles in the human forearm which bear his name (Wood, 1868; Macalister, 1875) and these have subsequently been reported with variable attachments (Wood, 1868; Macalister, 1875; Turner, 1879; Schäfer & Thane, 1894; Le Double, 1897; Dykes & Anson, 1944; Mangini, 1960; Malhotra et al. 1982; Kida, 1988; Tountas & Bergman, 1993). The accessory heads of the deep flexors of the forearm (Gantzer's muscles) have been described as 2 different small bellies which insert either into FPL or FDP. There are no previous reports which have mentioned the existence of an accessory muscle which inserts into both of the 2 deep flexors of the forearm as in the case presented here. PMID:9306208

  2. Structure of μ-MnAl4, a crystalline phase with composition close to that of quasicrystalline phases

    NASA Astrophysics Data System (ADS)

    Shoemaker, Clara Brink

    1988-10-01

    The structure of μ-MnAl4 has been determined by single-crystal x-ray diffraction. The space group is P63/mmc, a=19.98(1)B, c=24.673(4) Å, with 563 atoms per cell (average), and the formula is MnAl4.12. Parts of the structure resemble that of φ-Mn3Al10. Neither complete Mackay icosahedra (MI), nor Bergman polyhedra are present, but different fragments of MI occur. Mn atoms have 0 to 2 Mn atoms in the first coordination shell and 4 to 12 Mn atoms in the second shell. The predominant coordinations are, for Mn, icosahedron; for Al, bicapped pentagonal prism, other CN(12) configurations, and CN(13).

  3. Diffusion in a Cu-Zr metallic glass studied by microsecond-scale molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Wang, C. Z.; Mendelev, M. I.; Zhang, F.; Kramer, M. J.; Ho, K. M.

    2015-05-01

    Icosahedral short-range order (ISRO) has been widely accepted to be dominant in Cu-Zr metallic glasses (MGs). However, the diffusion mechanism and correlation of ISRO and medium-range order (MRO) to diffusion in MGs remain largely unexplored. Here, we perform a long time annealing up to 1.8 μs in molecular dynamics simulations to study the diffusion mechanism and the relationship between atomic structures and the diffusion path in a C u64.5Z r35.5 MG. It is found that most of the diffusing events performed by the diffusing atoms are outside ISRO and the Bergman-type MRO. The long-range diffusion in MGs is highly heterogeneous, via collective diffusing events through the liquidlike channels in the glass. Our results clearly demonstrate a strong correlation between the atomic structures and transport in MGs.

  4. Ab initio Ti-Zr-Ni phase diagram predicts stability of icosahedral TiZrNi quasicrystals

    NASA Astrophysics Data System (ADS)

    Hennig, R. G.; Carlsson, A. E.; Kelton, K. F.; Henley, C. L.

    2005-04-01

    The ab initio phase diagram determines the energetic stability of the icosahedral TiZrNi quasicrystal. The complete ab initio zero-temperature ternary phase diagram is constructed from the calculated energies of the elemental, binary and ternary Ti-Zr-Ni phases. For this, the icosahedral i -TiZrNi quasicrystal is approximated by periodic structures of up to 123 atoms/unit cell, based on a decorated-tiling model [R. G. Hennig, K. F. Kelton, A. E. Carlsson, and C. L. Henley, Phys. Rev. B 67, 134202 (2003)]. The approximant structures containing the 45-atom Bergman cluster are nearly degenerate in energy, and are all energetically stable against the competing phases. It is concluded that i -TiZrNi is a ground-state quasicrystal, as it is experimentally the low-temperature phase for its composition.

  5. A perturbation-based estimate algorithm for parameters of coupled ordinary differential equations, applications from chemical reactions to metabolic dynamics.

    PubMed

    Shiang, Keh-Dong

    2009-05-01

    Conversion of complex phenomena in medicine, pharmaceutical and systems biology fields to a system of ordinary differential equations (ODEs) and identification of parameters from experimental data and theoretical model equations can be treated as a computational engine to arrive at the best solution for chemical reactions, biochemical metabolic and intracellular pathways. Particularly, to gain insight into the pathophysiology of diabetes's metabolism in our current clinical studies, glucose kinetics and insulin secretion can be assessed by the ODE model. Parameter estimation is usually performed by minimizing a cost function which quantifies the difference between theoretical model predictions and experimental measurements. This paper explores how the numerical method and iteration program are developed to search ODE's parameters using the perturbation method, instead of the Gauss-Newton or Levenberg-Marquardt method. Several interesting applications, including Lotka-Volterra chemical reaction system, Lorenz chaos, dynamics of tetracycline hydrochloride concentration, and Bergman's Minimal Model for glucose kinetics are illustrated.

  6. Linear relations among holomorphic quadratic differentials and induced Siegel's metric on g

    NASA Astrophysics Data System (ADS)

    Matone, Marco; Volpato, Roberto

    2011-10-01

    We find the explicit form of the volume form on the moduli space of non-hyperelliptic Riemann surfaces induced by the Siegel metric, a long-standing question in string theory. This question is related to the explicit form of the (g-2)(g-3)/2 linearly independent relations among the 2-fold products of holomorphic abelian differentials, that are provided in the case of canonical curves of genus g ⩾ 4. Such relations can be completely expressed in terms of determinants of the standard normalized holomorphic abelian differentials. Remarkably, it turns out that the induced volume form is the Kodaira-Spencer map of the square of the Bergman reproducing kernel.

  7. Variational bounds on the effective moduli of anisotropic composites

    NASA Astrophysics Data System (ADS)

    Milton, Graeme W.; Kohn, Robert V.

    THE VRITIONAL inequalities of Hashin and Shtrikman are transformed to a simple and concise form. They are used to bound the effective conductivity tensor σ∗ of an anisotropic composite made from an arbitrary number of possibly anisotropic phases, and to bound the effective elasticity tensor C∗ of an anisotropic mixture of two well-ordered isotropic materials. The bounds depend on the conductivities and elastic moduli of the components and their respective volume fractions. When the components are isotropic the conductivity bounds, which constrain the eigenvalues of σ∗, include those previously obtained by Hashin and Shtrikman, Murat and Tartar, and Lurie and Cherkaev. Our approach can also be used in the context of linear elasticity to derive bounds on C∗ for composites comprised of an arbitrary number of anisotropic phases. For two-component composites our bounds are tighter than those obtained by Kantor and Bergman and by Francfort and Murat, and are attained by sequentially layered laminate materials.

  8. Ab initio studies of the reaction of hydrogen transfer from DNA to the calicheamicinone diradical.

    PubMed Central

    Sapse, A. M.; Rothchild, R.; Kumar, R.; Lown, J. W.

    2001-01-01

    BACKGROUND: The biological activity of enediyne chemotherapeutic (anti-cancer) agents is attributed to their ability to cleave duplex DNA. Part of the reaction of cleavage is the abstraction of hydrogens from the deoxyribose moiety of DNA by the biradical formed via a Bergman rearrangement. METHODS: The mechanism of the reaction of abstraction of two hydrogen atoms from two deoxyribophosphate molecules by the calicheamicinone biradical is studied with ab initio calculations at Hartree-Fock and post-Hartree-Fock level. The Titan program is used to perform the calculations. RESULTS: It is found that the reactions are exothermic and thus thermodynamically reasonable. CONCLUSIONS: The mechanism of DNA cleavage by the enediyne-containing drugs is likely to proceed by the abstraction of the hydrogens from deoxyribose by the biradical formed by the drug. Further studies should determine in which way the modification of the drug's structure would make this reaction even more exothermic and, thus, more likely to occur. PMID:11844867

  9. Iron Mineral Catalyzed C-H Activation As a Potential Pathway for Halogenation Processes

    NASA Astrophysics Data System (ADS)

    Tubbesing, C.; Schoeler, H. F.; Benzing, K.; Krause, T.; Lippe, S.; Rudloff, M.

    2014-12-01

    Due to increasing drinking water demand of mankind and an expected climate change the impact of salt lakes and salt deserts will increase within the next decades. Furthermore, a rising sea level influences coastal areas like salt marshes and abets processes which will lead to elevated organohalogen formation. An additional increase of the global warming potential, of particle formation and stratospheric ozone depletion is expected. Understanding these multifaceted processes is essential for mankind to be prepared for these alterations of the atmosphere. For example, Keppler et al. (2000) described the production of volatile halogenated organic compounds via oxidation of organic matter driven by ferric iron. However, the formation of long-chained alkyl halides in salt lakes is yet undisclosed. Despite the relative "inertness" of alkanes a direct halogenation of these compounds might be envisaged. In 2005 Vaillancourt et al. discovered a nonheme iron enzyme which is able to halogenate organic compounds via generating the high valent ferryl cation as reaction center. Based on various publications about C-H activation (Bergman, 2007) we postulate a halogenation process in which an iron containing minerals catalyse the C-H bond cleavage of organic compounds in soils. The generated organic radicals are highly reactive towards halides connected to the iron complex. We suggest that next to diagenetically altered iron containing enzymes, minerals such as oxides, hydroxides and sulfides are involved in abiotic halogenation processes. We applied the amino acid methionine as organic model compound and soluble iron species as reactants. All samples were incubated in aqueous phases containing various NaCl concentrations. As a result various halogenated ethanes and ethenes were identified as reaction products. References Bergman, R. G. (2007) Nature, 446(7134) 391-393 Keppler, F., et al. (2000) Nature, 403(6767) 298-301 Vaillancourt, F. H., et al. (2005) Nature, 436(7054) 1191-1194

  10. Inorganic nanoparticles for the spatial and temporal control of organic reactions: Applications to radical degradation of biopolymer networks

    NASA Astrophysics Data System (ADS)

    Walker, Joan Marie

    Nanoparticles of gold and iron oxide not only possess remarkable optical and magnetic properties, respectively, but are also capable of influencing their local environment with an astounding degree of precision. Using nanoparticles to direct the reactivity of organic molecules near their surface provides a unique method of spatial and temporal control. Enediynes represent an exceptional class of compounds that are thermally reactive to produce a diradical intermediate via Bergman cycloaromatization. While natural product enediynes are famously cytotoxic, a rich chemistry of synthetic enediynes has developed utilizing creative means to control this reactivity through structure, electronics, metal chelation, and external triggering mechanisms. In a heretofore unexplored arena for Bergman cyclization, we have investigated the reactivity of enediynes in connection with inorganic nanoparticles in which the physical properties of the nanomaterial are directly excited to thermally promote aromatization. As the first example of this methodology, gold nanoparticles conjugated with (Z)-octa-4-en-2,6-diyne-1,8-dithiol were excited with 514 nm laser irradiation. The formation of aromatic and polymeric products was confirmed through Raman spectroscopy and electron microscopy. Water soluble analogues Au-PEG-EDDA and Fe3O4-PEG-EDDA (EDDA = (Z)-octa-4-en-2,6-diyne-1,8-diamine) show similar reactivity under laser irradiation or alternating magnetic field excitation, respectively. Furthermore, we have used these functionalized nanoparticles to attack proteinaceous substrates including fibrin and extracellular matrix proteins, capitalizing on the ability of diradicals to disrupt peptidic bonds. By delivering a locally high payload of reactive molecules and thermal energy to the large biopolymer, network restructuring and collapse is achieved. As a synthetic extension towards multifunctional nanoparticles, noble metal seed-decorated iron oxides have also been prepared and assessed for

  11. Cooling rates dependence of medium-range order development in C u64 .5Z r35 .5 metallic glass

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Zhang, F.; Wang, C. Z.; Mendelev, M. I.; Kramer, M. J.; Ho, K. M.

    2015-02-01

    The atomic structure of metallic glasses (MGs) plays an important role in their properties. Numerous molecular dynamics (MD) simulations have revealed icosahedral short-range order (ISRO) as a dominant motif in Cu-Zr metallic glasses. However, the cooling rates utilized in most of the MD simulations (usually on the order of 1010 -13K /s ) can be too high to allow the structure to relax into the actual structures. By performing a long sub-Tg annealing of the C u64.5Z r35.5 alloy model at 700 K up to 2.0 μ s using MD simulations, we systematically address the evolution of medium-range order (MRO) as the cooling rates in MD simulations approach the experimental cooling rates (usually 103 -6K /s ). By reducing the effective cooling rates to as low as 2.8 ×107K /s , we found a significant enhancement of the ISRO and Bergman-type MRO. Comparing to the widely used face-, edge-, or vertex-sharing icosahedra, we propose that the Bergman-type MRO is a much more unambiguous metric to characterize the MRO in Cu-Zr MGs. By analyzing the network formed by interpenetrating icosahedra using the graphical theory, we show that the degree of interpenetration of the icosahedra centers increases with decreasing cooling rates. The network becomes aggressively assortative, indicating that higher degree nodes tend to cluster and form backbones in the MG. All these results show that the networks in the models prepared using lower cooling rates strongly deviate from a stringlike morphology.

  12. Comparison of optimal design methods in inverse problems

    NASA Astrophysics Data System (ADS)

    Banks, H. T.; Holm, K.; Kappel, F.

    2011-07-01

    Typical optimal design methods for inverse or parameter estimation problems are designed to choose optimal sampling distributions through minimization of a specific cost function related to the resulting error in parameter estimates. It is hoped that the inverse problem will produce parameter estimates with increased accuracy using data collected according to the optimal sampling distribution. Here we formulate the classical optimal design problem in the context of general optimization problems over distributions of sampling times. We present a new Prohorov metric-based theoretical framework that permits one to treat succinctly and rigorously any optimal design criteria based on the Fisher information matrix. A fundamental approximation theory is also included in this framework. A new optimal design, SE-optimal design (standard error optimal design), is then introduced in the context of this framework. We compare this new design criterion with the more traditional D-optimal and E-optimal designs. The optimal sampling distributions from each design are used to compute and compare standard errors; the standard errors for parameters are computed using asymptotic theory or bootstrapping and the optimal mesh. We use three examples to illustrate ideas: the Verhulst-Pearl logistic population model (Banks H T and Tran H T 2009 Mathematical and Experimental Modeling of Physical and Biological Processes (Boca Raton, FL: Chapman and Hall/CRC)), the standard harmonic oscillator model (Banks H T and Tran H T 2009) and a popular glucose regulation model (Bergman R N, Ider Y Z, Bowden C R and Cobelli C 1979 Am. J. Physiol. 236 E667-77 De Gaetano A and Arino O 2000 J. Math. Biol. 40 136-68 Toffolo G, Bergman R N, Finegood D T, Bowden C R and Cobelli C 1980 Diabetes 29 979-90).

  13. Non-self-averaging in Ising spin glasses and hyperuniversality.

    PubMed

    Lundow, P H; Campbell, I A

    2016-01-01

    Ising spin glasses with bimodal and Gaussian near-neighbor interaction distributions are studied through numerical simulations. The non-self-averaging (normalized intersample variance) parameter U_{22}(T,L) for the spin glass susceptibility [and for higher moments U_{nn}(T,L)] is reported for dimensions 2,3,4,5, and 7. In each dimension d the non-self-averaging parameters in the paramagnetic regime vary with the sample size L and the correlation length ξ(T,L) as U_{nn}(β,L)=[K_{d}ξ(T,L)/L]^{d} and so follow a renormalization group law due to Aharony and Harris [Phys. Rev. Lett. 77, 3700 (1996)PRLTAO0031-900710.1103/PhysRevLett.77.3700]. Empirically, it is found that the K_{d} values are independent of d to within the statistics. The maximum values [U_{nn}(T,L)]_{max} are almost independent of L in each dimension, and remarkably the estimated thermodynamic limit critical [U_{nn}(T,L)]_{max} peak values are also practically dimension-independent to within the statistics and so are "hyperuniversal." These results show that the form of the spin-spin correlation function distribution at criticality in the large L limit is independent of dimension within the ISG family. Inspection of published non-self-averaging data for three-dimensional Heisenberg and XY spin glasses the light of the Ising spin glass non-self-averaging results show behavior which appears to be compatible with that expected on a chiral-driven ordering interpretation but incompatible with a spin-driven ordering scenario. PMID:26871035

  14. Non-self-averaging in Ising spin glasses and hyperuniversality

    NASA Astrophysics Data System (ADS)

    Lundow, P. H.; Campbell, I. A.

    2016-01-01

    Ising spin glasses with bimodal and Gaussian near-neighbor interaction distributions are studied through numerical simulations. The non-self-averaging (normalized intersample variance) parameter U22(T ,L ) for the spin glass susceptibility [and for higher moments Un n(T ,L ) ] is reported for dimensions 2 ,3 ,4 ,5 , and 7. In each dimension d the non-self-averaging parameters in the paramagnetic regime vary with the sample size L and the correlation length ξ (T ,L ) as Un n(β ,L ) =[Kdξ (T ,L ) /L ] d and so follow a renormalization group law due to Aharony and Harris [Phys. Rev. Lett. 77, 3700 (1996), 10.1103/PhysRevLett.77.3700]. Empirically, it is found that the Kd values are independent of d to within the statistics. The maximum values [Unn(T,L ) ] max are almost independent of L in each dimension, and remarkably the estimated thermodynamic limit critical [Unn(T,L ) ] max peak values are also practically dimension-independent to within the statistics and so are "hyperuniversal." These results show that the form of the spin-spin correlation function distribution at criticality in the large L limit is independent of dimension within the ISG family. Inspection of published non-self-averaging data for three-dimensional Heisenberg and X Y spin glasses the light of the Ising spin glass non-self-averaging results show behavior which appears to be compatible with that expected on a chiral-driven ordering interpretation but incompatible with a spin-driven ordering scenario.

  15. [BODY ADIPOSITY AND ITS RELATIONSHIP OF METABOLIC SYNDROME COMPONENTS IN COLOMBIAN ADULTS].

    PubMed

    González-Ruíz, Katherine; Correa-Bautista, Jorge Enrique; Ramírez-Vélez, Robinson

    2015-10-01

    Objetivo: recientemente, Bergman et al. desarrollaron el indice de adiposidad corporal (IAC) como un marcador de obesidad por exceso de grasa corporal en la practica clinica. Este estudio valoro la prevalencia de obesidad y de sindrome metabolico (SM), ademas de examinar la relacion del IAC como predictor de riesgo en los componentes e indices aterogenicos asociados al SM en adultos de Bogota, Colombia. Métodos: estudio transversal en 690 hombres del sector educativo y administrativo de Bogota, Colombia. El IAC se estimo con la ecuacion de Bergman et al. Los componentes del SM evaluados fueron (circunferencia de cintura ≥ 90 cm; glucemia en ayunas ≥ 100 mg/dL; presion arterial ≥ 135/85 mmHg; trigliceridemia ≥ 150 mg/dL, y c-HDL ≤ 40 mg/dL. Se calcularon indices aterogenicos (colesterol/c-HDL, c-LDL/c-HDL, trigliceridos/c-HDL, indice lipidico-metabolico [ILM] y score de SM). Resultados: la prevalencia de obesidad por IAC (> 26,1%) y de SM fue de 50,1% y 19,1%, respectivamente. Los sujetos con SM e IAC > 26,1% presentaron menores niveles de c-HDL y mayor frecuencia en los componentes asociados al SM (circunferencia de cintura, colesterol total y trigliceridos sericos). Con relacion a los indices aterogenicos, el IAC fue capaz de predecir en 1,78 (IC95% 1,25- 2,55), 1,46 (IC95% 1,01-2,14), 1,97 (IC95% 1,29-3,02), 2,04 (IC95% 1,23-3,39) y 1,47 (IC95% 1,03-2,11) la elevacion en el c-LDL, ILM, score de SM y los cocientes CT/c-HDL, y trigliceridos/c-HDL, respectivamente (p < 0,05). Conclusión: los participantes con mayores valores en el IAC presentan mayor frecuencia y asociacion positiva con los componentes relacionados al SM.

  16. Study on electrostatic resonance of nanoprisms with sharp corners

    NASA Astrophysics Data System (ADS)

    Chan, Wai Soen; Ng, Ka Ki; Yu, Kin Wah

    2015-03-01

    We have studied the electrostatic resonance of metal nanoprisms with sharp corners numerically. We consider an infinite metal cylinder with polygonal base, e.g. square. The incident electric field lies in the plane of cross-section of the cylinder. Yu and co-workers proposed Green's function formalism (GFF) to numerically calculate the electric potential and field distribution in plasmonic systems. We will adopt the scheme to demonstrate the effect of sharp corners, particularly on the effect of electrostatic resonance spectrum, as in the spectral analysis proposed by Bergman and Milton. Hetherington and Thorpe investigated the conductivity of a sheet containing dilute inclusion with sharp corners, they made use of a conformal mapping approach to calculate the conductivity from circular inclusions. Helsing, McPhedran and Milton also investigated the optical properties of a metamaterial lattice with inclusions having sharp corners. We study the possibility of improving numerical accuracy by combining the conformal mapping approach and GFF. We may extend similar approach to investigate the properties of plasmonic systems, for examples nanoboties and nanostars.

  17. American Academy of Clinical Neuropsychology Consensus Conference Statement on the neuropsychological assessment of effort, response bias, and malingering.

    PubMed

    Heilbronner, Robert L; Sweet, Jerry J; Morgan, Joel E; Larrabee, Glenn J; Millis, Scott R

    2009-09-01

    During the past two decades clinical and research efforts have led to increasingly sophisticated and effective methods and instruments designed to detect exaggeration or fabrication of neuropsychological dysfunction, as well as somatic and psychological symptom complaints. A vast literature based on relevant research has emerged and substantial portions of professional meetings attended by clinical neuropsychologists have addressed topics related to malingering (Sweet, King, Malina, Bergman, & Simmons, 2002). Yet, despite these extensive activities, understanding the need for methods of detecting problematic effort and response bias and addressing the presence or absence of malingering has proven challenging for practitioners. A consensus conference, comprised of national and international experts in clinical neuropsychology, was held at the 2008 Annual Meeting of the American Academy of Clinical Neuropsychology (AACN) for the purposes of refinement of critical issues in this area. This consensus statement documents the current state of knowledge and recommendations of expert clinical neuropsychologists and is intended to assist clinicians and researchers with regard to the neuropsychological assessment of effort, response bias, and malingering. PMID:19735055

  18. Effective medium analysis of thermally evaporated Ag nanoparticle films for plasmonic enhancement in organic solar cell

    NASA Astrophysics Data System (ADS)

    Haidari, Gholamhosain; Hajimahmoodzadeh, Morteza; Fallah, Hamid Reza; Varnamkhasti, Mohsen Ghasemi

    2015-09-01

    Films of silver nanoparticles have optical properties that are useful for applications such as plasmonic light trapping in solar cells. We report on the simple fabrication of Ag nanoparticle films via thermal evaporation, with and without subsequent annealing. These films result in a random array of particles of various shapes and sizes. The modeling of such a vast collection of particles is still beyond reach of the modern computers. We show that it is possible to represent the silver island films by the Bergman effective mediums with the same optical properties. The effective medium method provides us with deep insight about the shape, the size and the distribution of nanoparticles. The far field simulations of solar cells, in which the silver island film is replaced with an effective medium layer, show a reduction in the absorption of active layer. Besides, the near field simulations based on finite-difference time-domain technique demonstrate that the near field effects on active layer absorption are negligible and this method highlights the importance of nanoparticles shapes. The PCPDTBT:PCBM solar cells with embedded silver island films are fabricated, and it is found that their performances show the similar trend. This insight can be used for the optical analysis of thermally evaporated Ag nanoparticle films for the improvement of organic solar cells.

  19. On Convergence Aspects of Spheroidal Monogenics

    NASA Astrophysics Data System (ADS)

    Georgiev, S.; Morais, J.

    2011-09-01

    Orthogonal polynomials have found wide applications in mathematical physics, numerical analysis, and other fields. Accordingly there is an enormous amount of variety of such polynomials and relations that describe their properties. The paper's main results are the discussion of approximation properties for monogenic functions over prolate spheroids in R3 in terms of orthogonal monogenic polynomials and their interdependences. Certain results are stated without proof for now. The motivation for the present study stems from the fact that these polynomials play an important role in the calculation of the Bergman kernel and Green's monogenic functions in a spheroid. Once these functions are known, it is possible to solve both basic boundary value and conformal mapping problems. Interestingly, most of the used methods have a n-dimensional counterpart and can be extended to arbitrary ellipsoids. But such a procedure would make the further study of the underlying ellipsoidal monogenics somewhat laborious, and for this reason we shall not discuss these general cases here. To the best of our knowledge, this does not appear to have been done in literature before.

  20. Soft Tissue Esthetic Norms for Mahabubnagar Population of Southern India

    PubMed Central

    Sinojiya, Jay; Aileni, Kaladhar Reddy; Rachala, Madhukar Reddy; Pyata, Jaipal Reddy; Mallikarjun, Vankre; Reddy, C. Manjunatha

    2014-01-01

    Aims: The Aim of the study was to establish Soft Tissue Cephalometric Norms for skeletal and dental relationships amongst the Mahabubnagar adult population. Materials and Methods: Sixty subjects (30 Males & 30 Females) subjects from different part of Mahabubnagar in the age group 18-25 Years (Mean age 21.3 Years) were selected at random for the study and lateral cephalograms were taken. All the cephalograms were traced by two operators using conventional hand tracing. The parameters used in the study were taken from Arnett and Bergman soft tissue cephalometric analysis (STCA). Overall 46 measurements including 40 linear, 6 angular parameters were used. Mean and standard deviation values were calculated. The difference between males and females were evaluated using student t-test. Results: The values obtained from the study showed significant difference in most of the parameters from that of Arnett et al., norms and between males and females within Mahabubnagar population. Conclusion: Males had thicker soft tissue structures, acute nasolabial angle, increased facial lengths and heights, increased midface deficiency, recessive lower face, more convex profile and less upright mandibular incisors than females within Mahabubnagar population. PMID:24596789

  1. Composition-dependent stability of the medium-range order responsible for metallic glass formation

    DOE PAGES

    Zhang, Feng; Ji, Min; Fang, Xiao-Wei; Sun, Yang; Wang, Cai-Zhuang; Mendelev, Mikhail I.; Kramer, M. J.; Napolitano, Ralph E.; Ho, Kai-Ming

    2014-09-18

    The competition between the characteristic medium-range order corresponding to amorphous alloys and that in ordered crystalline phases is central to phase selection and morphology evolution under various processing conditions. We examine the stability of a model glass system, Cu–Zr, by comparing the energetics of various medium-range structural motifs over a wide range of compositions using first-principles calculations. Furthermore, we focus specifically on motifs that represent possible building blocks for competing glassy and crystalline phases, and we employ a genetic algorithm to efficiently identify the energetically favored decorations of each motif for specific compositions. These results show that a Bergman-type motifmore » with crystallization-resisting icosahedral symmetry is energetically most favorable in the composition range 0.63 < xCu < 0.68, and is the underlying motif for one of the three optimal glass-forming ranges observed experimentally for this binary system (Li et al., 2008). This work establishes an energy-based methodology to evaluate specific medium-range structural motifs which compete with stable crystalline nuclei in deeply undercooled liquids.« less

  2. Effective medium based optical analysis with finite element method simulations to study photochromic transitions in Ag-TiO2 nanocomposite films

    NASA Astrophysics Data System (ADS)

    Abhilash, T.; Balasubrahmaniyam, M.; Kasiviswanathan, S.

    2016-03-01

    Photochromic transitions in silver nanoparticles (AgNPs) embedded titanium dioxide (TiO2) films under green light illumination are marked by reduction in strength and blue shift in the position of the localized surface plasmon resonance (LSPR) associated with AgNPs. These transitions, which happen in the sub-nanometer length scale, have been analysed using the variations observed in the effective dielectric properties of the Ag-TiO2 nanocomposite films in response to the size reduction of AgNPs and subsequent changes in the surrounding medium due to photo-oxidation. Bergman-Milton formulation based on spectral density approach is used to extract dielectric properties and information about the geometrical distribution of the effective medium. Combined with finite element method simulations, we isolate the effects due to the change in average size of the nanoparticles and those due to the change in the dielectric function of the surrounding medium. By analysing the dynamics of photochromic transitions in the effective medium, we conclude that the observed blue shift in LSPR is mainly because of the change in the dielectric function of surrounding medium, while a shape-preserving effective size reduction of the AgNPs causes decrease in the strength of LSPR.

  3. GT Merge Process: Version 1.0

    SciTech Connect

    Flanagan, M P; Dodge, D; Myers, S C

    2008-06-10

    This document summarizes the process used to merge GT25 and better data between LANL and LLNL for use in a tomographic inversion for Pn velocity of Eurasia. The merge process is automated and includes extensive quality control operations at each step. Events in common between the labs are identified and resolved using GT level criteria. Arrivals in common between the labs are also resolved through the use of agreed upon arrival author rankings. Finally, baselined origin times are computed for all crustal events using either teleseismic P-arrivals and the iasp91 model or, in certain regions, regional P-arrivals and regional velocity models that are known to be consistent with teleseismic iasp91 P-wave predictions. We combine the core tables from each lab and first resolve unique and common GT events between LANL and LLNL. Phase names are then checked and possibly adjusted for consistency. Next, we merge at the pick level so that each distinct EVENT-STATION-PHASE tuple has a unique arrival. All BMEB (Bondar-Myers-Engdahl-Bergman) GT are evaluated for adherence to their criteria, and possibly re-calculated. Finally, new origin times are computed (baselining) for the merged GT events. In addition to the reconciliation of events and picks between LANL and LLNL, the merge process involves several quality control steps that are intended to remove outlier and irrelevant data from the final results.

  4. Definition and Properties of the Libera Operator on Mixed Norm Spaces

    PubMed Central

    Pavlovic, Miroslav

    2014-01-01

    We consider the action of the operator ℒg(z) = (1 − z)−1∫z1‍f(ζ)dζ on a class of “mixed norm” spaces of analytic functions on the unit disk, X = Hα,νp,q, defined by the requirement g ∈ X⇔r ↦ (1 − r)αMp(r, g(ν)) ∈ Lq([0,1], dr/(1 − r)), where 1 ≤ p ≤ ∞, 0 < q ≤ ∞, α > 0, and ν is a nonnegative integer. This class contains Besov spaces, weighted Bergman spaces, Dirichlet type spaces, Hardy-Sobolev spaces, and so forth. The expression ℒg need not be defined for g analytic in the unit disk, even for g ∈ X. A sufficient, but not necessary, condition is that ∑n=0∞‍|g^(n)|/(n+1)<∞. We identify the indices p, q, α, and ν for which 1°ℒ is well defined on X, 2°ℒ acts from X to X, 3° the implication g∈X⇒∑n=0∞‍|g^(n)|/(n+1)<∞ holds. Assertion 2° extends some known results, due to Siskakis and others, and contains some new ones. As an application of 3° we have a generalization of Bernstein's theorem on absolute convergence of power series that belong to a Hölder class. PMID:24707211

  5. Lung dust and lung iron contents of coal workers in different coalfields in Great Britain

    PubMed Central

    Bergman, I.; Casswell, C.

    1972-01-01

    Bergman, I., and Casswell, C. (1972).Brit. J. industr. Med.,29, 160-168. Lung dust and lung iron contents of coal workers in different coalfields in Great Britain. Lung dust analyses from seven coalfields are studied and it is found that the average dust composition varies significantly with the rank of coal. The higher the rank, the higher the coal percentage and the lower the quartz percentage of the lung dust. This holds for all coalfields except in Scotland, where the lung dust contains mainly soot instead of coal. Samples of airborne dust collected at the coalface in different coalfields show a similar but small variability of composition with rank of coal, and the results from Scotland are in good agreement with the results from other coalfields. The amount of iron in simple pneumoconiosis lungs is related to their mineral and coal contents and to the factor `years underground'. The strongest relationship is with coal and mineral for coalface workers from England. For pit accident cases (all simple pneumoconiosis) mineral is important as well as years underground, while for simple pneumoconiosis cases from Scotland, years underground is the most important factor. PMID:4336667

  6. Mathematical analysis of a model for glucose regulation.

    PubMed

    Fessel, Kimberly; Gaither, Jeffrey B; Bower, Julie K; Gaillard, Trudy; Osei, Kwame; Rempala, Grzegorz A

    2016-02-01

    Diabetes affects millions of Americans, and the correct identification of individuals afflicted with this disease, especially of those in early stages or in progression towards diabetes, remains an active area of research. The minimal model is a simplified mathematical construct for understanding glucose-insulin interactions. Developed by Bergman, Cobelli, and colleagues over three decades ago, this system of coupled ordinary differential equations prevails as an important tool for interpreting data collected during an intravenous glucose tolerance test (IVGTT). In this study we present an explicit solution to the minimal model which allows for separating the glucose and insulin dynamics of the minimal model and for identifying patient-specific parameters of glucose trajectories from IVGTT. As illustrated with patient data, our approach seems to have an edge over more complicated methods currently used. Additionally, we also present an application of our method to prediction of the time to baseline recovery and calculation of insulin sensitivity and glucose effectiveness, two quantities regarded as significant in diabetes diagnostics. PMID:26776262

  7. Selective Organic and Organometallic Reactions in Water-Soluble Host-Guest Supramolecular Systems

    SciTech Connect

    Pluth, Michael D.; Raymond, Kenneth N.; Bergman, Robert G.

    2008-02-16

    Inspired by the efficiency and selectivity of enzymes, synthetic chemists have designed and prepared a wide range of host molecules that can bind smaller molecules with their cavities; this area has become known as 'supramolecular' or 'host-guest' chemistry. Pioneered by Lehn, Cram, Pedersen, and Breslow, and followed up by a large number of more recent investigators, it has been found that the chemical environment in each assembly - defined by the size, shape, charge, and functional group availability - greatly influences the guest-binding characteristics of these compounds. In contrast to the large number of binding studies that have been carried out in this area, the exploration of chemistry - especially catalytic chemistry - that can take place inside supramolecular host cavities is still in its infancy. For example, until the work described here was carried out, very few examples of organometallic reactivity inside supramolecular hosts were known, especially in water solution. For that reason, our group and the group directed by Kenneth Raymond decided to take advantage of our complementary expertise and attempt to carry out metal-mediated C-H bond activation reactions in water-soluble supramolecular systems. This article begins by providing background from the Raymond group in supramolecular coordination chemistry and the Bergman group in C-H bond activation. It goes on to report the results of our combined efforts in supramolecular C-H activation reactions, followed by extensions of this work into a wider range of intracavity transformations.

  8. Characterizing the chemical pathways for water formation--a deep search for hydrogen peroxide.

    PubMed

    Parise, Bérengère; Bergman, Per; Menten, Karl

    2014-01-01

    In 2011, hydrogen peroxide (HOOH) was observed for the first time outside the solar system (Bergman et al., Astron. Astrophys., 2011, 531, L8). This detection appeared a posteriori to be quite natural, as HOOH is an intermediate product in the formation of water on the surface of dust grains. Following up on this detection, we present a search for HOOH in a diverse sample of sources in different environments, including low-mass protostars and regions with very high column densities, such as Infrared Dark Clouds (IRDCs). We do not detect the molecule in any other source than Oph A, and derive 3sigma upper limits for the abundance of HOOH relative to H2 lower than that in Oph A for most sources. This result sheds a different light on our understanding of the detection of HOOH in Oph A, and shifts the question of why this source seems to be special. Therefore we rediscuss the detection of HOOH in Oph A, as well as the implications of the low abundance of HOOH, and its similarity with the case of O2. Our chemical models show that the production of HOOH is extremely sensitive to temperature, and is favored only in the range 20-30 K. The relatively high abundance of HOOH observed in Oph A suggests that the bulk of the material lies at a temperature in the range 20-30 K.

  9. Disordered structures of the TM-Mg-Zn 1/1 quasicrystal approximants (TM = Hf, Zr, or Ti) and chemical intergrowth.

    PubMed

    Gómez, Cesar Pay; Ohhashi, Satoshi; Yamamoto, Akiji; Tsai, An Pang

    2008-09-15

    The structures of three quasicrystal approximant phases in the TM-Mg-Zn (TM = Hf, Zr, Ti) systems with the analyzed compositions Hf5Mg18Zn77, Zr5Mg18Zn77, and Ti5.5Mg17.5Zn77 have been synthesized, and their structures have been analyzed by single-crystal X-ray diffraction. The structure analyses revealed that these cubic phases with the space group Pm3 contain two different rhombic-triacontahedral clusters. These clusters are so-called Bergman-type atomic clusters and previously known approximants of face-centered icosahedral (F-type) quasicrystals are composed only of Mackay-type clusters, thus these compounds are seen as new prototype structures. Electron density maps calculated by the maximum entropy method (MEM) show that one of the atomic clusters displays characteristic structural disorder. The disorder in these phases is related to the chemical intergrowth of different Friauf polyhedra, and the prospects of new guide lines for finding quasicrystals composed of such polyhedra are discussed.

  10. About the atomic structures of icosahedral quasicrystals

    NASA Astrophysics Data System (ADS)

    Quiquandon, Marianne; Gratias, Denis

    2014-01-01

    This paper is a survey of the crystallographic methods that have been developed these last twenty five years to decipher the atomic structures of the icosahedral stable quasicrystals since their discovery in 1982 by D. Shechtman. After a brief recall of the notion of quasiperiodicity and the natural description of Z-modules in 3-dim as projection of regular lattices in N>3-dim spaces, we give the basic geometrical ingredients useful to describe icosahedral quasicrystals as irrational 3-dim cuts of ordinary crystals in 6-dim space. Atoms are described by atomic surfaces (ASs) that are bounded volumes in the internal (or perpendicular) 3-dim space and the intersections of which with the physical space are the actual atomic positions. The main part of the paper is devoted to finding the major properties of quasicrystalline icosahedral structures. As experimentally demonstrated, they can be described with a surprisingly few high symmetry ASs located at high symmetry special points in 6-dim space. The atomic structures are best described by aggregations and intersections of high symmetry compact interpenetrating atomic clusters. We show here that the experimentally relevant clusters are derived from one generic cluster made of two concentric triacontahedra scaled by τ and an external icosidodecahedron. Depending on which ones of the orbits of this cluster are eventually occupied by atoms, the actual atomic clusters are of type Bergman, Mackay, Tsai and others….

  11. Topologically induced semiconductivity in icosahedral Al-Pd-Re and its approximants

    NASA Astrophysics Data System (ADS)

    Krajčí, M.; Hafner, J.

    2007-01-01

    We demonstrate that the opening of a semiconducting band-gap in the electronic spectrum of the i-Al-Pd-Re quasicrystal and its approximants is due to the formation of a topological band-gap, in analogy to the band-gap found in the FeSi (B20) structure. In both systems we have identified a network of linear chains of alternating Si(Al) and transition-metal (TM) atoms extending along twofold symmetry directions. In i-Al-Pd-Re the chains of alternating Al and TM atoms extend from a center of the pseudo-Mackay (M) cluster over the surface of the Bergman cluster to the center of another neighboring M cluster. Substitutional Al/Pd defects and a fragmentation of the chains by phason defects lead to the formation of localized states in the band-gap. The band-gap of the real i-Al-Pd-Re quasicrystal is filled by localized states. The i-Al-Pd-Re quasicrystal thus behaves as a disordered semiconductor.

  12. New types of multishell nanoclusters with a Frank-Kasper polyhedral core in intermetallics.

    PubMed

    Blatov, Vladislav A; Ilyushin, Gregory D; Proserpio, Davide M

    2011-06-20

    A comprehensive study of the occurrence of two-shell clusters with the first shell as a Frank-Kasper polyhedron Z12, Z14, Z15, or Z16 (Frank-Kasper nanoclusters) is performed for 22,951 crystal structures of intermetallics containing only metal atoms. It is shown that besides the familiar Bergman and Mackay clusters, two more types of high-symmetrical icosahedron-based nanoclusters are rather frequent; they both have a 50-atom second shell. Moreover, two types of high-symmetrical Frank-Kasper nanoclusters with a Friauf-polyhedron (Z16) core are revealed; these nanoclusters have 44 and 58 atoms in the second shell. On the contrary, Z14 and Z15 Frank-Kasper polyhedra have been found to be rare and improper to form distinct nanoclusters in crystals. The second shells of Frank-Kasper nanoclusters have been revealed possessing their own stability: they can be realized in nanoclusters with different internal polyhedra and can shift around the core shell. The role of Frank-Kasper nanoclusters in assembling intermetallic crystal structures is illustrated by several examples.

  13. A Numerical Model for Magnetohydrodynamic Waves in a Stably-Stratified Layer in Earth's Core

    NASA Astrophysics Data System (ADS)

    Knezek, N. R.; Buffett, B. A.

    2015-12-01

    A numerical model for magnetohydrodynamic waves in a thin shell is developed and applied to study the effect of a stably-stratified layer in Earth's core on geomagnetic secular variation. The model employs a spherical coordinate system with finite differences in r and θ and Fourier decomposition in Φ. The model is linearized assuming a background azimuthal velocity field UΦ(r,θ) and an arbitrary background magnetic field Br,θ,Φ(r,θ). The Boussinesq approximation is employed and the buoyancy forces are prescribed in terms of a spatially variable Brunt-Vaisala frequency N(r,θ). The equations are cast into a sparse generalized eigenvalue problem by assuming solutions of the form uj,bj,p=CjeimΦ+λt and eigenmodes are found. Good agreement is obtained with previous approximate analytical solutions for zonal (m=0) magnetic-Archimedes-Coriolis (MAC) waves (e.g. Braginsky, 1993), global magnetic-Rossby (m>0) waves (e.g. Braginsky, 1998), and equatorially-trapped magnetic-Rossby waves (e.g. Bergman, 1993). This model is employed to study the origins of the fast equatorial waves observed by Chulliat et al. (2015) in recent high-resolution magnetic field models to constrain plausible properties of the stably-stratified layer and core-surface magnetic field.

  14. Impact of deformation on the atomic structures and dynamics of a Cu-Zr metallic glass: A molecular dynamics study

    DOE PAGES

    Zhang, Y.; Mendelev, M. I.; Wang, C. Z.; Ott, R.; Zhang, F.; Besser, M. F.; Ho, K. M.; Kramer, M. J.

    2014-11-03

    Despite numerous studies on the atomic structures of Cu-Zr metallic glasses (MGs), their inherent structural ordering, e.g., medium-range order (MRO), remains difficult to describe. Specifically lacking is an understanding of how the MRO responds to deformation and the associated changes in atomic mobility. In this paper, we focus on the impact of deformation on MRO and associated effect on diffusion in a well-relaxed Cu64.5Zr35.5 MG by molecular dynamics simulations. The Cu-Zr MG exhibits a larger elastic limit of 0.035 and a yield stress of 3.5 GPa. The cluster alignment method was employed to characterize the icosahedral short-range order (ISRO) andmore » Bergman-type medium-range order (BMRO) in the models upon loading and unloading. From this analysis, we find the disruption of both ISRO and BMRO occurs as the strain reaches about 0.02, well below the elastic limit. Within the elastic limit, the total fractions of ISRO or BMRO can be fully recovered upon unloading. The diffusivity increases six to eight times in regions undergoing plastic deformation, which is due to the dramatic disruption of the ISRO and BMRO. As a result, by mapping the spatial distributions of the mobile atoms, we demonstrate the increase in atomic mobility is due to the extended regions of disrupted ISRO and more importantly BMRO.« less

  15. Transits of Venus, 1761 and 1769.

    NASA Astrophysics Data System (ADS)

    Abrahams, P.

    2003-12-01

    The Transits of Venus of 1761 and 1769 were widely anticipated, due to the efforts of Edmond Halley and Joseph-Nicolas Delisle in promoting observations to determine solar parallax. Extensive planning resulted in widespread participation; with at least 110 different observing stations stations worldwide for one or both of the events. Results from the 1761 expeditions derived solar parallax measurements between 8.28 and 10.60 arc seconds. The 1769 results were much better, 8.43 to 8.80 arc seconds, as compared with the accurate value of 8.79 arc seconds. This presentation will note the efforts of Halley, Delisle, and James Ferguson in promoting scientific observation of the transit. The poster will include the observations of Thorbern Bergman at Uppsala, Sweden; Samuel Dunn at the Royal Observatory, Greenwich; Charles Green at King George's Island; Samuel Horsley at Oxford; and William Smith at Norriton. These observers are distinguished from their contemporaries by the interesting graphic aids they used to present their studies.

  16. Digital-map grids of mean-annual precipitation for 1961-90, and generalized skew coefficients of annual maximum streamflow for Oklahoma

    USGS Publications Warehouse

    Rea, A.H.; Tortorelli, R.L.

    1997-01-01

    This digital report contains two digital-map grids of data that were used to develop peak-flow regression equations in Tortorelli, 1997, 'Techniques for estimating peak-streamflow frequency for unregulated streams and streams regulated by small floodwater retarding structures in Oklahoma,' U.S. Geological Survey Water-Resources Investigations Report 97-4202. One data set is a grid of mean annual precipitation, in inches, based on the period 1961-90, for Oklahoma. The data set was derived from the PRISM (Parameter-elevation Regressions on Independent Slopes Model) mean annual precipitation grid for the United States, developed by Daly, Neilson, and Phillips (1994, 'A statistical-topographic model for mapping climatological precipitation over mountainous terrain:' Journal of Applied Meteorology, v. 33, no. 2, p. 140-158). The second data set is a grid of generalized skew coefficients of logarithms of annual maximum streamflow for Oklahoma streams less than or equal to 2,510 square miles in drainage area. This grid of skew coefficients is taken from figure 11 of Tortorelli and Bergman, 1985, 'Techniques for estimating flood peak discharges for unregulated streams and streams regulated by small floodwater retarding structures in Oklahoma,' U.S. Geological Survey Water-Resources Investigations Report 84-4358. To save disk space, the skew coefficient values have been multiplied by 100 and rounded to integers with two significant digits. The data sets are provided in an ASCII grid format.

  17. Definition and properties of the libera operator on mixed norm spaces.

    PubMed

    Pavlovic, Miroslav

    2014-01-01

    We consider the action of the operator ℒg(z) = (1 - z)(-1)∫ z (1)‍f(ζ)dζ on a class of "mixed norm" spaces of analytic functions on the unit disk, X = H α,ν (p,q) , defined by the requirement g ∈ X ⇔ r ↦ (1 - r) (α) M p (r, g ((ν))) ∈ L (q) ([0,1], dr/(1 - r)), where 1 ≤ p ≤ ∞, 0 < q ≤ ∞, α > 0, and ν is a nonnegative integer. This class contains Besov spaces, weighted Bergman spaces, Dirichlet type spaces, Hardy-Sobolev spaces, and so forth. The expression ℒg need not be defined for g analytic in the unit disk, even for g ∈ X. A sufficient, but not necessary, condition is that Σ(n=0)|(∞)|ĝ(n)/(n + 1) < ∞. We identify the indices p, q, α, and ν for which 1°ℒ is well defined on X, 2 °ℒ acts from X to X, 3° the implication g ∈ X [Symbol: see text] Σ(n = 0)(∞) |/ĝ(n)|(n+1) < ∞ holds. Assertion 2° extends some known results, due to Siskakis and others, and contains some new ones. As an application of 3° we have a generalization of Bernstein's theorem on absolute convergence of power series that belong to a Hölder class.

  18. Determination of collagen content, concentration, and sub-types in kidney tissue.

    PubMed

    Samuel, Chrishan S

    2009-01-01

    Fibrosis and sclerosis are widely recognized as hallmarks of progressive renal disease and are caused by the excessive accumulation of connective tissue, mostly collagen. The detection of collagen content, concentration (collagen content/dry weight tissue), and sub-types from kidney tissues is therefore an important part of determining the extent of renal fibrosis in ageing and diseased states. This chapter describes a colorimetric-based hydroxyproline assay used to estimate total collagen content and concentration. Based on the method of Bergman and Loxley (8), this spectrophotometric technique estimates total collagen by measuring the hydroxyproline content of tissue. The assay relies on the fact that the collagen triple helix is one of the few proteins that contain the amino acid hydroxyproline. The second part of this chapter describes the use of sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) to isolate, detect and quantify changes in the soluble and insoluble interstitial collagen sub-types. This technique complements the hydroxyproline assay by providing a means of identifying which interstitial collagens are altered in renal disease.

  19. Composition-dependent stability of the medium-range order responsible for metallic glass formation

    SciTech Connect

    Zhang, Feng; Ji, Min; Fang, Xiao-Wei; Sun, Yang; Wang, Cai-Zhuang; Mendelev, Mikhail I.; Kramer, M. J.; Napolitano, Ralph E.; Ho, Kai-Ming

    2014-09-18

    The competition between the characteristic medium-range order corresponding to amorphous alloys and that in ordered crystalline phases is central to phase selection and morphology evolution under various processing conditions. We examine the stability of a model glass system, Cu–Zr, by comparing the energetics of various medium-range structural motifs over a wide range of compositions using first-principles calculations. Furthermore, we focus specifically on motifs that represent possible building blocks for competing glassy and crystalline phases, and we employ a genetic algorithm to efficiently identify the energetically favored decorations of each motif for specific compositions. These results show that a Bergman-type motif with crystallization-resisting icosahedral symmetry is energetically most favorable in the composition range 0.63 < xCu < 0.68, and is the underlying motif for one of the three optimal glass-forming ranges observed experimentally for this binary system (Li et al., 2008). This work establishes an energy-based methodology to evaluate specific medium-range structural motifs which compete with stable crystalline nuclei in deeply undercooled liquids.

  20. {sup 1}H NMR study of hydrogen in quasicrystalline Ti{sub 0.45{minus}x}V{sub x}Zr{sub 0.38}Ni{sub 0.17}

    SciTech Connect

    Shastri, A.; Majzoub, E.H.; Borsa, F.; Gibbons, P.C.; Kelton, K.F.

    1998-03-01

    {sup 1}H nuclear-magnetic-resonance (NMR) spectra and spin-lattice relaxation rates (R{sub 1}) were studied in the hydrogenated Ti{sub 0.45{minus}x}V{sub x}Zr{sub 0.38}Ni{sub 0.17} quasicrystal for x=0.00, 0.02, and a hydrogen-to-metal-atom ratio (H/M)=1.88. NMR measurements were made from 4 to 550 K at resonance frequencies of 8, 18, 55, and 200 MHz. Theoretical {sup 1}H second-moment values (M{sub 2}) were calculated based on Bergman and Mackay cluster models and compared with experimental M{sub 2} values. The R{sub 1} data reveal a distribution of activation energies for the {sup 1}H diffusion through the quasilattice; the distribution is insensitive to the vanadium concentration, x. Low-temperature R{sub 1} data reveal an additional low-temperature relaxation mechanism that is not yet well understood. {copyright} {ital 1998} {ital The American Physical Society}

  1. Degradation of tocopherols in rice bran oil submitted to heating at different temperatures.

    PubMed

    Bruscatto, M H; Zambiazi, R C; Sganzerla, M; Pestana, V R; Otero, D; Lima, R; Paiva, F

    2009-10-01

    The objective of this study has been to evaluate the stability of alpha-, (gamma+beta)-, and delta-tocopherols in rice bran oil chemically refined submitted to heating in a heater without air circulation and shielded from light, at temperatures of 100 degrees C and 180 degrees C. The collection of samples took place after 48, 96, 144, 192, 240, 336, and 432 h of heating and were stored in amber-colored flasks and frozen (-18 degrees C). The analyses of tocopherols took place in accordance with the method by Chen and Bergman (2005), with slight modifications, utilizing a system of high efficiency system of liquid chromatography. It was observed that the alpha-tocopherol is present at higher concentration in rice bran oil (328.4 mg/kg), followed by (gamma+beta)-tocopherol (99.1 mg/kg), and delta-tocopherol (7.7 mg/kg). The alpha-tocopherol in rice bran oil submitted to 100 degrees C showed a reduction of 28.65% at the end of 432 h of heating whereas when submitted to 180 degrees C temperature; its reduction was of 100% at the end of 240 h of heating. The contents of (gamma+beta)- and delta-tocopherol in rice bran oil at the end of 432 h of heating at 100 degrees C was of 79.9 and 6.4 mg/100 g, respectively.

  2. Impact of deformation on the atomic structures and dynamics of a Cu-Zr metallic glass: A molecular dynamics study

    SciTech Connect

    Zhang, Y.; Mendelev, M. I.; Wang, C. Z.; Ott, R.; Zhang, F.; Besser, M. F.; Ho, K. M.; Kramer, M. J.

    2014-11-03

    Despite numerous studies on the atomic structures of Cu-Zr metallic glasses (MGs), their inherent structural ordering, e.g., medium-range order (MRO), remains difficult to describe. Specifically lacking is an understanding of how the MRO responds to deformation and the associated changes in atomic mobility. In this paper, we focus on the impact of deformation on MRO and associated effect on diffusion in a well-relaxed Cu64.5Zr35.5 MG by molecular dynamics simulations. The Cu-Zr MG exhibits a larger elastic limit of 0.035 and a yield stress of 3.5 GPa. The cluster alignment method was employed to characterize the icosahedral short-range order (ISRO) and Bergman-type medium-range order (BMRO) in the models upon loading and unloading. From this analysis, we find the disruption of both ISRO and BMRO occurs as the strain reaches about 0.02, well below the elastic limit. Within the elastic limit, the total fractions of ISRO or BMRO can be fully recovered upon unloading. The diffusivity increases six to eight times in regions undergoing plastic deformation, which is due to the dramatic disruption of the ISRO and BMRO. As a result, by mapping the spatial distributions of the mobile atoms, we demonstrate the increase in atomic mobility is due to the extended regions of disrupted ISRO and more importantly BMRO.

  3. Finite time thermodynamic coupling in a biochemical network.

    PubMed

    Dasgupta, Anjan Kr

    2014-03-01

    The paper describes some thermodynamic constrains and relations in biochemical or metabolic network and provides a basis for entropy enthalpy compensation. Conventional definition of macroscopic forces and fluxes leads to a paradox namely, non-existence of positive efficiency of a chemically driven process. This paradox is resolved by deriving an appropriate definition of macroscopic force using the local balance equations. Entropy enthalpy compensation, whose thermodynamic basis is so far unclear, also follows. The method provides an account of how reactive pathways are coupled, the strength of coupling between a pathway pair depending on the product of their respective enthalpies. The obligatory role of the presence of a common chemical intermediate in defining coupling becomes unnecessary; such intermediate-free coupling being a key feature of metabolic energy transduction. The redefined flux and force can also be exploited to explain surface to volume ratio dependence of coupled networks. Lastly, the thermodynamic rationale for the Bergman's eco-geographic rule, namely the reduced ability of larger animals to avoid stress follows from the generalized expression for coupling coefficients. Higher surface to volume ratio is shown to make the organism resistant to external perturbations.

  4. Preliminary Results from a Search for a Nebula in the Vicinity of Sirius

    NASA Astrophysics Data System (ADS)

    Mutz, Steven B.; Wyckoff, Susan

    1992-12-01

    Ptolemy, Seneca, and several Babylonian and mediaeval texts have described Sirius (now A1V for the visible component) as a red star (Gry and Bonnet-Bidaud 1990, Schlosser and Bergman 1985). If true, then the present color of Sirius would be very difficult to explain in terms of current theories of stellar evolution. A possible explanation is that Sirius was eclipsed by a small, dark nebula such as a Bok globule (see Gry and Bonnet-Bidaud 1990). To search for such an object J, H, K, and CO (near 2.4 mu ) imaging of the stellar field near Sirius' apparent postion of 2000 years ago was performed using the University of Arizona's 256x256 IR array on their 61-inch Mt Bigelow telescope. Preliminary (J-H) vs. (H-K) diagrams indicate the presence of color excesses in the area of study (following the methods of Jones et al. 1980, 1984). Examination of the Palomar Sky Survey plates for the region of interest shows several areas where the stellar number density is more than 3 sigma smaller than the average stellar density for that area of the sky. Also, the stellar density for these depleted regions is higher on the red Palomar plate than the number density of the regions on the blue plate, suggesting a redder stellar population in these regions, which may be due to the presence of intervening material.

  5. Electronic Structure of Ethynyl Substituted Cyclobutadienes

    NASA Astrophysics Data System (ADS)

    Emmert, Frank Lee Emmert, III; Thompson, Stephanie J.; Slipchenko, Lyudmila V.

    2011-06-01

    We investigated the effects of ethynyl substitution on the electronic structure of cyclobutadiene. These species are involved in Bergman Cyclization reactionsand are possible intermediates in the formation of fullerenes and graphite sheets. Prediction of the electronic energy of cyclobutadiene is challenging for single-reference ab initio methods such as HF, MP2 or DFT because of Jahn-Teller distortions and the diradical character of the singlet state. We determined the vertical and adiabatic singlet-triplet energy splittings, the natural charges and spin densities in substituted cyclobutadienes, using the equations of motion spin flip coupled cluster with single and double excitations (EOM-SF-CCSD) method that accurately describes diradical states. The adiabatic singlet-triplet gaps decrease upon substituent addition, but the singlet state is always lower in energy. However, we found that the results are affected by spin-contamination of the reference state and deteriorate when an unrestricted HF reference is employed. O. L. Chapman, C. L. McIntosh, J. Pacansky, "Cyclobutadiene" J. Am. Chem. Soc. 1973, 95, (2), 614-617. N. S. Goroff, "Mechanism of Fullerene Formation." Acc. Chem. Res. 1996, 29, (2), 77-83. L.V. Slipchenko and A.I. Krylov, "Singlet-triplet gaps in diradicals by the Spin-Flip approach: A benchmark study", J. Chem. Phys. 2002, 117, 4694-4708.

  6. ALTERNATIVE REMEDIATION TECHNOLOGY STUDY FOR GROUNDWATER TREATMENT AT 200-PO-1 OPERABLE UNIT AT HANFORD SITE

    SciTech Connect

    DADO MA

    2008-07-31

    This study focuses on the remediation methods and technologies applicable for use at 200-PO-I Groundwater Operable Unit (OU) at the Hanford Site. The 200-PO-I Groundwater au requires groundwater remediation because of the existence of contaminants of potential concern (COPC). A screening was conducted on alternative technologies and methods of remediation to determine which show the most potential for remediation of groundwater contaminants. The possible technologies were screened to determine which would be suggested for further study and which were not applicable for groundwater remediation. COPCs determined by the Hanford Site groundwater monitoring were grouped into categories based on properties linking them by remediation methods applicable to each COPC group. The screening considered the following criteria. (1) Determine if the suggested method or technology can be used for the specific contaminants found in groundwater and if the technology can be applied at the 200-PO-I Groundwater au, based on physical characteristics such as geology and depth to groundwater. (2) Evaluate screened technologies based on testing and development stages, effectiveness, implementability, cost, and time. This report documents the results of an intern research project conducted by Mathew Dado for Central Plateau Remediation in the Soil and Groundwater Remediation Project. The study was conducted under the technical supervision of Gloria Cummins and management supervision of Theresa Bergman and Becky Austin.

  7. Processable high-carbon-yielding polymer for micro- and nanofabrication

    NASA Astrophysics Data System (ADS)

    Perpall, Mark W.; Zengin, Huseyin; Perera, K. Prasanna U.; Zhou, Wensheng; Shah, Hiren; Wu, Xinyu; Creager, Stephen E.; Smith, Dennis W., Jr.; Foulger, Stephen H.; Ballato, John M.

    2003-01-01

    Bis-ortho-Diynyl Arene (BODA) monomers polymerize to network polynapthalene by the thermally-driven Bergman cyclization and subsequent radical polymerization via oligomeric intermediates that can be melt or solution processed. Further heating of the network to 1000 °C affords a high-yield glassy carbon structure that retains the approximate size and dimensions of the polymer precursor. The higher carbon-yield for BODA networks (75- 80 % by mass) is significantly greater than that of traditional phenol-formaldehyde resins and other carbon precursor polymers leading to its greater dimensional stability. Phenyl terminated BODA derived polymers were fabricated using microprocessing such as the micromolding in capillaries (MIMIC) technique, direct microtransfer molding, and molding in quartz capillary tubes. Nano-scale fabrication using closed packed silica spheres as templates was demonstrated with an hydroxy-terminated monomer which exhibits greatly enhanced compatibility for silica surfaces. After pyrolysis to glassy carbon, the silica is chemically etched leaving an inverse carbon opal photonic crystal which is electrically conductive. The wavelength of light diffracted is a function of the average refractive index of the carbon/ filler composite, which can be modified for use as sensitive detector elements.

  8. Soft Tissue Cephalometric Norms for Central India (Malwa) Female Population

    PubMed Central

    Raghav, Shweta; Baheti, Kamalshikha; Hansraj, Varun; Rishad, Mohamed; Kanungo, Himanshu; Bejoy, Pulayampatt Unni

    2014-01-01

    Background: The various soft tissue traits that contribute to an aesthetically pleasing face. This should be considered during orthodontic treatment. The aim of the present study was to propose soft tissue norms for Central Indian (Malwa) female population. Materials and Methods: Facial photographs of 78 patients of age group 18-26 years were taken in Department of Orthodontics, Rau, Indore, which were then subjected to a selection process and 30 top scorers (30 females) were selected. Lateral cephalograms of individuals were taken and soft tissue profile as well as related osseous and dental structures standard tracing were made on the acetate matte tracing paper. Then eighteen soft tissue traits were studied as described by Bergman. Results: The present study showed that, a mild convexity of the face and the resulting tendency toward Class II in females is acceptable esthetically. A fuller upper lip is considered balanced and esthetic. Increase in lip incompetency is considered unaesthetic. Conclusion: A mild convexity of the face and the resulting tendency toward Class II in females is acceptable esthetically. Individual norms are necessary for a population in order to plan and deliver quality treatment. PMID:25395794

  9. Mathematical analysis of a model for glucose regulation.

    PubMed

    Fessel, Kimberly; Gaither, Jeffrey B; Bower, Julie K; Gaillard, Trudy; Osei, Kwame; Rempala, Grzegorz A

    2016-02-01

    Diabetes affects millions of Americans, and the correct identification of individuals afflicted with this disease, especially of those in early stages or in progression towards diabetes, remains an active area of research. The minimal model is a simplified mathematical construct for understanding glucose-insulin interactions. Developed by Bergman, Cobelli, and colleagues over three decades ago, this system of coupled ordinary differential equations prevails as an important tool for interpreting data collected during an intravenous glucose tolerance test (IVGTT). In this study we present an explicit solution to the minimal model which allows for separating the glucose and insulin dynamics of the minimal model and for identifying patient-specific parameters of glucose trajectories from IVGTT. As illustrated with patient data, our approach seems to have an edge over more complicated methods currently used. Additionally, we also present an application of our method to prediction of the time to baseline recovery and calculation of insulin sensitivity and glucose effectiveness, two quantities regarded as significant in diabetes diagnostics.

  10. Theoretical analyses of cellular transmembrane voltage in suspensions induced by high-frequency fields.

    PubMed

    Zou, Yong; Wang, Changzhen; Peng, Ruiyun; Wang, Lifeng; Hu, Xiangjun

    2015-04-01

    A change of the transmembrane voltage is considered to cause biophysical and biochemical responses in cells. The present study focuses on the cellular transmembrane voltage (Δφ) induced by external fields. We detail analytical equations for the transmembrane voltage induced by external high-frequency (above the relaxation frequency of the cell membrane) fields on cells of a spherical shape in suspensions and layers. At direct current (DC) and low frequencies, the cell membrane was assumed to be non-conductive under physiologic conditions. However, with increasing frequency, the permittivity of the cytoplasm/extracellular medium and conductivity of the membrane must be accounted for. Our main work is to extend application of the analytical solution of Δφ to the high-frequency range. We first introduce the transmembrane voltage generated by DC and low-frequency exposures on a single cell. Then, we focus on cell suspensions exposed to high-frequency fields. Using the effective medium theory and the reasonable assumption, the approximate analytical solution of Δφ on cells in suspensions and layers can be derived. Phenomenological effective medium theory equations cannot be used to calculate the local electric field of cell suspensions, so we raised a possible solution based on the Bergman theory.

  11. GT Merge Process: Version 2.0

    SciTech Connect

    Flanagan, M P; Dodge, D; Myers, S C

    2008-06-10

    This document summarizes the process used to merge GT25 and better data between LANL and LLNL. The merge also includes OUO arrivals provided by AFTAC for events in the merge. The merge process is mostly automated and includes extensive quality control operations at each step. Events in common between the labs are identified and resolved using GT level criteria. Arrivals in common between the labs are also resolved through the use of agreed upon arrival author rankings. Finally, baselined origin times are computed for all crustal events using either teleseismic P-arrivals and the iasp91 model or, in certain regions, regional P-arrivals and regional velocity models that are known to be consistent with teleseismic iasp91 P-wave predictions. We combine the core tables from each contributor and resolve unique and common GT events between contributors. Next, we merge at the pick level so that each distinct EVENT-STATION-PHASE tuple has a unique arrival. All BMEB (Bondar-Myers-Engdahl-Bergman) GT are recalculated and evaluated for adherence to their criteria. Finally, new origin times are computed (baselining) for the merged GT events. In addition to the reconciliation of events and picks between contributors, the merge process involves several quality control steps that are intended to remove outlier and irrelevant data from the final results. The process is described in the section entitled 'Merge Steps'.

  12. Temperature measurements using selected Tm and Dy lines in Metal Halide Lamps

    NASA Astrophysics Data System (ADS)

    Aiura, Y.; Lawler, J. E.

    2003-10-01

    The 1 m Fourier transform spectrometer (FTS) at the National Solar Observatory on Kitt Peak was used to record UV to IR emission spectra of Metal Halide-High Intensity Discharge (MH-HID) lamps with doses containing rare earth salts. All intrinsic structure is fully resolved in these spectra. Many additive lines were found to have nearly perfect Lorentzian profiles and to be surprisingly narrow (FWHM < 1 cm-1) [1]. Fitting these profiles to Lorentzian functions provides a sensitive test for radiation trapping and line blending [1]. We have used this fitting approach along with recently measured absolute transition probabilities [2,3] to select sets of lines in Tm I, Tm II, Dy I, and Dy II which are good for temperature determinations in MH-HID lamps. [1 ] H. Adler, L. Riley, & J. E. Lawler in Proceedings of the Ninth International Symposium on the Science and Technology of Light Sources LS:9 ed: R S Bergman (2001, Ithaca: Cornell University Press) p 129. [2] M. E. Wickliffe & J. E. Lawler, J. Opt. Soc. Am. B 14, 737 (1997) [3] M. E. Wickliffe, J. E. Lawler, & G. Nave, J. Quant. Spectrosc. Radiat. Transfer 66, 363 (2000).

  13. The Unscented Kalman Filter estimates the plasma insulin from glucose measurement.

    PubMed

    Eberle, Claudia; Ament, Christoph

    2011-01-01

    Understanding the simultaneous interaction within the glucose and insulin homeostasis in real-time is very important for clinical treatment as well as for research issues. Until now only plasma glucose concentrations can be measured in real-time. To support a secure, effective and rapid treatment e.g. of diabetes a real-time estimation of plasma insulin would be of great value. A novel approach using an Unscented Kalman Filter that provides an estimate of the current plasma insulin concentration is presented, which operates on the measurement of the plasma glucose and Bergman's Minimal Model of the glucose insulin homeostasis. We can prove that process observability is obtained in this case. Hence, a successful estimator design is possible. Since the process is nonlinear we have to consider estimates that are not normally distributed. The symmetric Unscented Kalman Filter (UKF) will perform best compared to other estimator approaches as the Extended Kalman Filter (EKF), the simplex Unscented Kalman Filter (UKF), and the Particle Filter (PF). The symmetric UKF algorithm is applied to the plasma insulin estimation. It shows better results compared to the direct (open loop) estimation that uses a model of the insulin subsystem.

  14. PREFACE: Continuum Models and Discrete Systems Symposia (CMDS-12)

    NASA Astrophysics Data System (ADS)

    Chakrabarti, Bikas K.

    2011-09-01

    The 12th International Symposium on Continuum Models and Discrete Systems (CMDS-12) (http://www.saha.ac.in/cmp/cmds.12/) took place at the Saha Institute of Nuclear Physics in Kolkata from 21-25 February 2011. Previous CMDS symposia were held in Kielce (Poland, 1975), Mont Gabriel (Canada, 1977), Freudenstadt (Federal Republic of Germany, 1979), Stockholm (Sweden, 1981), Nottingham (United Kingdom, 1985), Dijon (France, 1989), Paderborn (Germany, 1992), Varna (Bulgaria, 1995), Istanbul (Turkey, 1998), Shoresh (Israel, 2003) and Paris (France, 2007). The broad interdisciplinary character, limited number of participants (not exceeding 100) and informal and friendly atmosphere of these meetings has made them a well-acknowledged place to make highly fruitful contacts and exchange ideas, methods and results. The purpose of CMDS is to bring together scientists with different backgrounds who work on continuum theories of discrete mechanical and thermodynamical systems in the fields of mathematics, theoretical and applied mechanics, physics, material science, and engineering. The spirit of the CMDS meetings is to stimulate extensive and active interdisciplinary research. The International Scientific Committee members of this conference were: David J Bergman (Chairman CMDS 10), Tel Aviv University, Israel; Bikas K Chakrabarti (Chairman CMDS 12), Saha Institute of Nuclear Physics, India; Alex Hansen, Norwegian University of Science and Technology, Norway; Hans Jürgen Herrmann, Institute for Building Materials, ETH, Switzerland; Esin Inan (Chairman CMDS 9), Istanbul Technical University, Turkey; Dominique Jeulin (Chairman CMDS 11), Ecole des Mines de Paris, France; Frank Juelicher, Max-Planck-Institute for the Physics of Complex Systems, Germany; Hikaru Kawamura, University of Osaka, Japan; Graeme Milton, University of Utah, USA; Natalia Movchan, University of Liverpool, UK; and Ping Sheng, The Hong Kong University of Science and Technology, Hong Kong. At CMDS-12 the topics

  15. PFAS - A threat for groundwater and drinking water supply in Sweden?

    NASA Astrophysics Data System (ADS)

    Lewis, Jeffrey; Banzhaf, Stefan; Ahlkrona, Malva; Arnheimer, Berit; Barthel, Roland; Bergvall, Martin; Blomquist, Niklas; Jacks, Gunnar; Jansson, Cecilia; Lissel, Patrik; Marklund, Lars; Olofsson, Bo; Persson, Kenneth M.; Sjöström, Jan; Sparrenbom, Charlotte

    2015-04-01

    Perfluoroalkyl substances (PFAS) are a group of anthropogenic environmental pollutants that are widely distributed in the global environment. They have multiple industrial uses, including water repellents in clothing, paper coatings and firefighting foam. According to a study released by the Environmental Directorate of the OECD, they are persistent, bioaccumulative and toxic to mammalian species (OECD, 2002). In some municipal drinking water wells in Sweden, measured concentrations of PFAS found to be several hundred times higher than the allowed threshold values. This has created a huge public concern and has recently attracted much media attention in Sweden (e.g. Afzelius et al., 2014; Bergman et al., 2014; Lewis et al., 2014). PFAS findings raised questions such as "What can we do to solve the problem?" When it comes to drinking water, there are a number of techniques that can ensure that PFAS levels are reduced to acceptable levels. This may be a costly challenge, but from a technical point of view it is possible. To ensure the safety of drinking water from a public health perspective is obviously a top priority. However, international experience shows that the cost of cleaning up PFAS in groundwater may be significantly higher than continuously treat drinking water in water works. Approximately fifty percent of Sweden's drinking water comes from groundwater. As a result, there are several ongoing and planned PFAS-related environmental and drinking-water investigations in Sweden. Many aquifers that supply municipal water plants are located in areas of sand and gravel deposits. Such soils have relatively high permeabilities, which permits extraction of large volumes of water. However, the downside to high permeabilities is that they also allow dissolved contaminants as PFAS to spread over large areas. If one disregards the health risks linked to its presence in drinking water, PFAS have an impact on three of Sweden's national environmental quality objectives

  16. Cost and waste volume reduction in HEPA filter trains by effective pre-filtration

    SciTech Connect

    Chadwick, Chris

    2007-07-01

    Data published elsewhere (Moore, et al., 1992; Bergman et al., 1997) suggests that the then costs of disposable type Glass Fibre HEPA filtration trains to the DOE was $55 million per year (based on an average usage of HEPA panels of 11,748 pieces per year between 1987 and 1990), $50 million of which was attributable to installation, testing, removal and disposal. The same authors suggest that by 1995 the number of HEPA panels being used had dropped to an estimated 4000 pieces per year due to the ending of the Cold War. The yearly cost to the DOE of 4000 units per year was estimated to be $29.5 million using the same parameters that previously suggested the $55 million figure. Within that cost estimate, $300 each was the value given to the filter and $4,450 was given to peripheral activity per filter. Clearly, if the $4,450 component could be reduced, tremendous saving could result, in addition to a significant reduction in the legacy burden of waste volumes. This same cost is applied to both the 11,748 and 4000 usage figures. The work up to now has focussed on the development of a low cost, long life (cleanable), direct replacement of the traditional filter train. This paper will review an alternative strategy, that of preventing the contaminating dust from reaching and blinding the HEPA filters, and thereby removing the need to replace them. What has become clear is that 'low cost' and 'Metallic HEPA' are not compatible terms. The original Bergman et al., 1997 work suggested that 1000 cfm (cubic feet per minute) (1690 m{sup 3}/hr) stainless HEPAs could be commercially available for $5000 each after development (although the $70,000 development unit may be somewhat exaggerated - the authors own company have estimated development units able to be retrofitted into strengthened standard housings would be available for perhaps $30,000). The likely true cost of such an item produced industrially in significant numbers may be closer to $15,000 each. That being the case

  17. Investigations of the Electronic Properties and Surface Structures of Aluminium-Rich Quasicrystalline Alloys

    SciTech Connect

    Jason A. Barrow

    2003-08-05

    The work presented in this dissertation has investigated three distinct areas of interest in the field of quasicrystals: bulk structure, transport properties, and electronic structure. First, they have described the results of a study which explored the fundamental interactions between the atomic species of the icosahedral Al-Pd-Mn quasicrystal. The goal of this work was to determine whether the pseudo-MacKay or Bergman type clusters have a special stability or are merely a geometric coincidence. This was carried out by using laser vaporization to produce gas-phase metal clusters, which were analyzed using time-of-flight mass spectrometry. Both the kinetic and thermodynamic stabilities of the clusters were probed. The data indicated no special stability for either pseudo-MacKay or Bergman type clusters as isolated units. This, however, is not proof that these clusters are simply a geometric coincidence. It is possible that such clusters only have stability in the framework of the bulk matrix and do not exist as isolated units. Next, they have reported their investigations of the bulk thermal transport properties of a decagonal Al-Ni-Co two dimensional quasicrystal in the temperature range 373K-873K. The properties of a sample oriented along the periodic axis and another oriented along the aperiodic axis were measured. A high degree of anisotropy was observed between the aperiodic and periodic directions. Additionally, the properties were measured for a sample miscut to an orientation 45{sup o} off-axis. The properties of the miscut sample were shown to have good agreement with a theoretical model used to describe thermal transport in metallic single crystals. This model only considers thermal transport by a free-electron gas; therefore, agreement with experimental data suggests the validity of the Drude free-electron model for the decagonal Al-Ni-Co at these temperatures. Consequently, the observed anisotropy may be adequately described using classical transport

  18. Development of an icosahedral quasicrystal and two approximants in the Ca-Au-Sn system: syntheses and structural analyses.

    PubMed

    Lin, Qisheng; Corbett, John D

    2010-11-15

    The realm of Tsai-type (YCd(6)-type) quasicrystals (QCs) and their approximants (ACs) continues to expand to the east in the periodic table. The heavy tetrel Sn is now one of the major components in the new Ca(15.0(5))Au(60.0(4))Sn(25.0(2)) (atom %) icosahedral QC and in the corresponding 1/1 and 2/1 ACs. (The 2/1 AC with Yb is also established.) Single-crystal X-ray diffraction on a 1/1 AC gives the refined formula of Ca(3)Au(14.36(3))Sn(4.38(5)) in space group Im3, a = 15.131(1) Å, whereas a representative 2/1 AC gives Ca(13)Au(47.2(1))Sn(28.1(1)), Pa3 and a = 24.444(1) Å. Both ACs contain five-shell multiply endohedral triacontahedral clusters as the common building blocks, as in the parent structure of YCd(6). The 2/1 AC also contains four Ca(2)-dimer-centered prolate rhombohedra (PRs) in the unit cell. The long-range order between triacontahedra and PRs in the 2/1 AC is the same as those in Bergman-type 2/1 ACs. A TB-LMTO-ASA calculation on an ideal 1/1 AC model reveals a shallow pseudogap in the total densities-of-states data around the Fermi energy, as expected. The depth of the pseudogap is considerably enhanced through interactions between the Ca 3d states and s and p states of Au and Sn. PMID:20939550

  19. Development of an icosahedral quasicrystal and two approximants in the Ca-Au-Sn system: syntheses and structural analyses.

    PubMed

    Lin, Qisheng; Corbett, John D

    2010-11-15

    The realm of Tsai-type (YCd(6)-type) quasicrystals (QCs) and their approximants (ACs) continues to expand to the east in the periodic table. The heavy tetrel Sn is now one of the major components in the new Ca(15.0(5))Au(60.0(4))Sn(25.0(2)) (atom %) icosahedral QC and in the corresponding 1/1 and 2/1 ACs. (The 2/1 AC with Yb is also established.) Single-crystal X-ray diffraction on a 1/1 AC gives the refined formula of Ca(3)Au(14.36(3))Sn(4.38(5)) in space group Im3, a = 15.131(1) Å, whereas a representative 2/1 AC gives Ca(13)Au(47.2(1))Sn(28.1(1)), Pa3 and a = 24.444(1) Å. Both ACs contain five-shell multiply endohedral triacontahedral clusters as the common building blocks, as in the parent structure of YCd(6). The 2/1 AC also contains four Ca(2)-dimer-centered prolate rhombohedra (PRs) in the unit cell. The long-range order between triacontahedra and PRs in the 2/1 AC is the same as those in Bergman-type 2/1 ACs. A TB-LMTO-ASA calculation on an ideal 1/1 AC model reveals a shallow pseudogap in the total densities-of-states data around the Fermi energy, as expected. The depth of the pseudogap is considerably enhanced through interactions between the Ca 3d states and s and p states of Au and Sn.

  20. On the oscillator realization of conformal U(2, 2) quantum particles and their particle-hole coherent states

    SciTech Connect

    Calixto, M. Pérez-Romero, E.

    2014-08-01

    We revise the unireps. of U(2, 2) describing conformal particles with continuous mass spectrum from a many-body perspective, which shows massive conformal particles as compounds of two correlated massless particles. The statistics of the compound (boson/fermion) depends on the helicity h of the massless components (integer/half-integer). Coherent states (CS) of particle-hole pairs (“excitons”) are also explicitly constructed as the exponential action of exciton (non-canonical) creation operators on the ground state of unpaired particles. These CS are labeled by points Z (2×2 complex matrices) on the Cartan-Bergman domain D₄=U(2,2)/U(2)², and constitute a generalized (matrix) version of Perelomov U(1, 1) coherent states labeled by points z on the unit disk D₁=U(1,1)/U(1)². First, we follow a geometric approach to the construction of CS, orthonormal basis, U(2, 2) generators and their matrix elements and symbols in the reproducing kernel Hilbert space H{sub λ}(D₄) of analytic square-integrable holomorphic functions on D₄, which carries a unitary irreducible representation of U(2, 2) with index λϵN (the conformal or scale dimension). Then we introduce a many-body representation of the previous construction through an oscillator realization of the U(2, 2) Lie algebra generators in terms of eight boson operators with constraints. This particle picture allows us for a physical interpretation of our abstract mathematical construction in the many-body jargon. In particular, the index λ is related to the number 2(λ – 2) of unpaired quanta and to the helicity h = (λ – 2)/2 of each massless particle forming the massive compound.

  1. [EVALUATION OF THE BODY ADIPOSITY INDEX IN PREDICTING PERCENTAGE BODY FAT AMONG COLOMBIAN ADULTS].

    PubMed

    González-Ruíz, Katherine; Correa-Bautista, Jorge Enrique; Ramírez-Vélez, Robinson

    2015-07-01

    Objetivo: el índice de adiposidad corporal (IAC) es un sencillo y nuevo método de predicción del porcentaje de grasa corporal (%GC) a través de una simple ecuación que incluye la circunferencia de cadera y la estatura. Hasta la fecha, pocos estudios han evaluado el IAC en la determinación el exceso de grasa en la población colombiana. El objetivo de este estudio fue evaluar la utilidad del IAC como predictor del %GC en adultos de Colombia. Métodos: estudio transversal en 204 hombres del sector educativo de Bogotá, Colombia. Se estimó el IAC con la ecuación de Bergman et al. [(circunferencia de cadera, en cm)/((estatura, en m)1,5 )-18)]. El %GC se determinó a través de bioimpedancia eléctrica tetrapolar (BIA) como la medida de referencia de la adiposidad. Se utilizó el análisis de Bland-Altman para evaluar el grado de acuerdo entre ambos métodos, IAC y BIA, y se evaluaron las relaciones con otras medidas antropométricas mediante el coeficiente de correlación de Pearson. Resultados: en la población general, el IAC sobreestima el %GC (diferencia de medias: 12,5% [IC95% = -4,04% a -21.02%]), en especial en sujetos con niveles bajos de adiposidad (diferencia de medias: 10,2 ± 3,3). Tras ajustar por edad, el IAC muestra correlaciones significativas con el IMC (r = 0,480), la relación cintura-estatura (r = 0,557) y el %GC por BIA (r = 0,777), p.

  2. Endomorphisms of spaces of virtual vectors fixed by a discrete group

    NASA Astrophysics Data System (ADS)

    Rădulescu, F.

    2016-04-01

    A study is made of unitary representations π of a discrete group G that are of type II when restricted to an almost-normal subgroup Γ\\subseteq G. The associated unitary representation \\overlineπ {p} of G on the Hilbert space of `virtual' Γ_0-invariant vectors is investigated, where Γ_0 runs over a suitable class of finite-index subgroups of Γ. The unitary representation \\overlineπ {p} of G is uniquely determined by the requirement that the Hecke operators for all Γ_0 are the `block-matrix coefficients' of \\overlineπ {p}. If π\\vert_Γ is an integer multiple of the regular representation, then there is a subspace L of the Hilbert space of π that acts as a fundamental domain for Γ. In this case the space of Γ-invariant vectors is identified with L. When π\\vert_Γ is not an integer multiple of the regular representation (for example, if G=\\operatorname{PGL}(2, Z \\lbrack 1/p \\rbrack ), Γ is the modular group, π belongs to the discrete series of representations of \\operatorname{PSL}(2, R), and the Γ-invariant vectors are cusp forms), π is assumed to be the restriction to a subspace H_0 of a larger unitary representation having a subspace L as above. The operator angle between the projection P_L onto L (typically, the characteristic function of the fundamental domain) and the projection P_0 onto the subspace H_0 (typically, a Bergman projection onto a space of analytic functions) is the analogue of the space of Γ-invariant vectors. It is proved that the character of the unitary representation \\overlineπ {p} is uniquely determined by the character of the representation π. Bibliography: 53 titles.

  3. The interpretation of crustal dynamics data in terms of plate motions and regional deformation near plate boundaries

    NASA Astrophysics Data System (ADS)

    Solomon, Sean C.

    During our participation in the NASA Crustal Dynamics Project under NASA contract NAS-27339 and grant NAG5-814 for the period 1982-1991, we published or submitted for publication 30 research papers and 52 abstracts of presentations at scientific meetings. In addition, five M.I.T. Ph.D. students (Eric Bergman, Steven Bratt, Dan Davis, Jeanne Sauber, Anne Sheehan) were supported wholly or in part by this project during their thesis research. Highlights of our research progress during this period include the following: application of geodetic data to determine rates of strain in the Mojave block and in central California and to clarify the relation of such strain to the San Andreas fault and Pacific-North American plate motions; application of geodetic data to infer post seismic deformation associated with large earthquakes in the Imperial Valley, Hebgen Lake, Argentina, and Chile; determination of the state of stress in oceanic lithosphere from a systematic study of the centroid depths and source mechanisms of oceanic intraplate earthquakes; development of models for the state of stress in young oceanic regions arising from the differential cooling of the lithosphere; determination of the depth extent and rupture characteristics of oceanic transform earthquakes; improved determination of earthquake slip vectors in the Gulf of California, an important data set for the estimation of Pacific-North American plate motions; development of models for the state of stress and mechanics of fold-and-thrust belts and accretionary wedges; development of procedures to invert geoid height, residual bathymetry, and differential body wave travel time residuals for lateral variations in the characteristic temperature and bulk composition of the oceanic upper mantle; and initial GPS measurements of crustal deformation associated with the Imperial-Cerro Prieto fault system in southern California and northern Mexico. Full descriptions of the research conducted on these topics may be

  4. On the origin of the heat capacity feature of annealed ices and ice clathrates, and interpreting water's diffusivity in terms of the entropy

    NASA Astrophysics Data System (ADS)

    Johari, G. P.

    2000-08-01

    In order to investigate the origins of (i) the spontaneous temperature rise on annealing pure hexagonal and cubic ices and ice clathrates and (ii) the sigmoid-shape increase in the heat capacity, C p, on heating the annealed samples, the enthalpy and entropy decrease on annealing of pure cubic ice and one ice clathrate have been determined from their C p data. This decrease is found to be much higher than that expected from orientational relaxation of H 2O molecules and that calculated from the spontaneous decrease in the Bjerrum or orientational defects concentrations. On this basis and the known observation that dopants not only decrease the relaxation time of the ices and ice clathrates but also modify the shape of the C p-increase feature, it is concluded that the spontaneous temperature rise on annealing occurs when some of the H 2O molecules achieve a preferential orientation, which is equivalent to their partial proton ordering. The sigmoid-shape C p-feature observed on heating the annealed samples is therefore due to the time- and temperature-dependent recovery of their random orientations or complete proton disorder. This is fundamentally different from structural relaxation in glasses whose entropy of disorder itself increases on heating. In a second aspect of the study, the known temperature dependence of the self-diffusion coefficient of water is used to calculate two fundamental quantities of the configurational entropy theory: (i) the size of the cooperatively rearranging regions, which is 4.7 molecules at 150 K, and (ii) the temperature-invariant energy, which is 7.4 kJ mol -1. These seem plausible and similar to those observed for other liquids. Finally, it is pointed out that a comparison of bulk water's dielectric properties with those of the ions afflicted, two-molecule thick water layer between the platelets of sodium vermiculite clay [R. Bergman, J. Sweson, Nature 403 (2000) 283], is inappropriate on fundamental grounds.

  5. On the oscillator realization of conformal U(2, 2) quantum particles and their particle-hole coherent states

    NASA Astrophysics Data System (ADS)

    Calixto, M.; Pérez-Romero, E.

    2014-08-01

    We revise the unireps. of U(2, 2) describing conformal particles with continuous mass spectrum from a many-body perspective, which shows massive conformal particles as compounds of two correlated massless particles. The statistics of the compound (boson/fermion) depends on the helicity h of the massless components (integer/half-integer). Coherent states (CS) of particle-hole pairs ("excitons") are also explicitly constructed as the exponential action of exciton (non-canonical) creation operators on the ground state of unpaired particles. These CS are labeled by points Z (2 × 2 complex matrices) on the Cartan-Bergman domain {D}_4=U(2,2)/U(2)^2, and constitute a generalized (matrix) version of Perelomov U(1, 1) coherent states labeled by points z on the unit disk {D}_1=U(1,1)/U(1)^2. First, we follow a geometric approach to the construction of CS, orthonormal basis, U(2, 2) generators and their matrix elements and symbols in the reproducing kernel Hilbert space H_λ ({D}_4) of analytic square-integrable holomorphic functions on {D}_4, which carries a unitary irreducible representation of U(2, 2) with index λ in {N} (the conformal or scale dimension). Then we introduce a many-body representation of the previous construction through an oscillator realization of the U(2, 2) Lie algebra generators in terms of eight boson operators with constraints. This particle picture allows us for a physical interpretation of our abstract mathematical construction in the many-body jargon. In particular, the index λ is related to the number 2(λ - 2) of unpaired quanta and to the helicity h = (λ - 2)/2 of each massless particle forming the massive compound.

  6. Of blood, inflammation and gunshot wounds: the history of the control of sepsis.

    PubMed

    Thurston, A J

    2000-12-01

    Galen (AD 129-199) propounded the notion that all wounds healed by second intention and the concept of laudable pus became unshakeable for almost 15 centuries. But William of Saliceto (AD ca 1210-1280) held quite firmly that pus formation was bad for both wound and patient and proclaimed that wounds should heal by first intention. The first rational theory of the nature of infection was by Fracastoro (1478-1553), a physician of Verona who regarded infection as being due to the passage of minute bodies from one person to another. But it was not until the work of Pasteur (1822-1895) that bacteriology took a significant leap forward. The association between bacteria and infection was slow to be accepted. The work of Semmelweis (1818-1865) is notable for his association between bacterial infection and puerperal fever. Lister (1827-1912) began the modern movement to control infection with his pioneering work in antiseptic surgery. Other contributions came from von Bergman (1836-1907; steam sterilization of instruments) and Halstead (1852-1922; rubber gloves for surgeons). The aseptic system has changed very little since then except for the innovations of Sir John Charnley (1911-1982; the laminar flow enclosure). The development of safe antibacterial drugs has been confined to the 20th century. This was led by Domagk (1895-1964; sulfonamides) and was followed by Sir Alexander Fleming (1881-1955), Sir Howard Walter Florey (1898-1968) and Sir Ernest Boris Chain (1906-1979; penicillin) and Selman Waksman (1888-1973; actinomycin).

  7. Periodic orbits, damped transitions and targeted energy transfers in oscillators with vibro-impact attachments

    NASA Astrophysics Data System (ADS)

    Lee, Young S.; Nucera, Francesco; Vakakis, Alexander F.; McFarland, D. Michael; Bergman, Lawrence A.

    2009-09-01

    We study complex damped and undamped dynamics and targeted energy transfers (TETs) in systems of coupled oscillators, consisting of single-degree-of-freedom primary linear oscillators (LOs) with vibro-impact attachments, acting, in essence, as vibro-impact nonlinear energy sinks (VI NESs). First, the complicated dynamics of such VI systems is demonstrated by computing the VI periodic orbits of underlying Hamiltonian systems and depicting them in appropriate frequency-energy plots (FEPs). Then, VI damped transitions and distinct ways of passive TETs from the linear oscillators to the VI attachments for various parameter ranges and initial conditions are investigated. As in the case of smooth stiffness nonlinearity [Y. Lee, G. Kerschen, A. Vakakis, P. Panagopoulos, L. Bergman, D.M. McFarland, Complicated dynamics of a linear oscillator with a light, essentially nonlinear attachment, Physica D 204 (1-2) (2005) 41-69], both fundamental and subharmonic TET can be realized in the VI systems under consideration. It is found that the most efficient mechanism for VI TET is through the excitation of highly energetic VI impulsive orbits (IOs), i.e., of periodic or quasiperiodic orbits corresponding to zero initial conditions except for the initial velocities of the linear oscillators. In contrast to NESs with smooth essential nonlinearities considered in previous works, VI NESs are capable of passively absorbing and locally dissipating significant portions of the energies of the primary systems to which they are attached, at fast time scale. This renders such devices suitable for applications, like seismic mitigation, where dissipation of vibration energy in the early, highly energetic regime of the motion is a critical requirement.

  8. New icosahedral nanoclusters in crystal structures of intermetallic compounds: Topological types of 50-atom deltahedra D50 in samson phases β-Mg2Al3 and ɛ-Mg23Al30

    NASA Astrophysics Data System (ADS)

    Blatov, V. A.; Ilyushin, G. D.

    2012-12-01

    A database of intermetallic compounds has been compiled using the TOPOS program package. This database includes 514 topological types, containing 12- and 13-atom icosahedral i clusters. An isolated group of 1649 i clusters is described by 14 point groups and their maximum symmetry D 3 d (bar 3 m) and T h ( m bar 3) is established, respectively, in 47 and 25 types of crystal structures. A structural analysis of the outer quasispherical shells showed that local 63-atom i configurations 1@12@50, which contain 50 atoms in the second layer, are implemented in 8 out of 19 cases. Examples of new topologically different types of 50-atom D50 deltahedra in the Samson phases ɛ-Mg23Al30 and β-Mg2Al3 are presented. Four topologically different sites with coordination numbers of 5, 6, 6, or 7 are established in the ɛ shell and seven sites with coordination numbers of 5, 5, 6, 6, 6, 6, or 7 are found in the β shell. The inner i clusters for the β-Mg2Al3 structure (with the symmetry bar 3 m) and the ɛ-Mg23Al30 structure (with the symmetry bar 3) have a similar chemical composition, i.e., Mg7Al6 and Mg6Al7, and their 50-atom shells are chemically identical to 18Mg + 32Al. The configurations found supplement the series of known two-layer icosahedral Bergman and Mackay clusters in the form of deltahedra with 32- and 42-atom shells.

  9. Limited Diversity among Human Isolates of Bartonella henselae

    PubMed Central

    Dillon, B.; Valenzuela, J.; Don, R.; Blanckenberg, D.; Wigney, D. I.; Malik, R.; Morris, A. J.; Robson, J. M.; Iredell, J.

    2002-01-01

    A study of 59 isolates of Bartonella henselae reveals relatively limited diversity among those of human origin (n = 28). Either of two distinct alleles of both gltA and 16S ribosomal DNA (rDNA) was found in all isolates, with a high level of congruity between 16S and gltA inheritance among proven human pathogens. Human isolates from all over Eastern Australia were most commonly 16S rDNA (Bergmans) type I, with the same gltA allele as the type strain (Houston-1). Comparable feline isolates were more commonly 16S type II, with less congruity of inheritance between 16S and gltA alleles. Previously described arbitrarily primed PCR and EagI-HhaI infrequent restriction site PCR fingerprinting techniques separated Bartonella species effectively but lacked discriminating power within B. henselae. Examination of the 16-23S intergenic spacer region revealed for several strains several point mutations as well as a repeat sequence of unknown significance which is readily detected by HaeIII restriction fragment length polymorphism analysis. The bacteriophage-associated papA gene was present in all isolates. Enterobacterial repetitive intergenic consensus PCR proved to be a useful and robust typing tool and clearly separated human isolates (including imported strains) from the majority of feline isolates. Our data are consistent with published evidence and with previous suggestions of intragenomic rearrangements in the type strain and suggest that human isolates come from a limited subset of B. henselae strains. They strengthen arguments for careful exploration of genotype-phenotype relationships and for the development of a multilocus enzyme electrophoresis and multilocus sequence typing-based approach to the phylogeny of B. henselae. PMID:12454174

  10. Annealing of directionally solidified alloys revisited: No loss of solidification texture in Earth’s inner core

    NASA Astrophysics Data System (ADS)

    Al-Khatatbeh, Yahya; Bergman, Michael I.; Lewis, Daniel J.; Mason, Zachary; Zhu, Laura; Rosenstock, Sarita

    2013-10-01

    Bergman et al. (2010) found experimental evidence for recrystallization and loss of solidification texture during annealing of directionally solidified hexagonal close-packed (hcp) Zn-rich Sn alloys. They suggested that this could support the model of Alboussiere et al. (2010) and Monnereau et al. (2010), in which the Earth’s inner core translates convectively eastwards with enhanced solidification in the western hemisphere and melting in the eastern, because as inner core material translates eastwards and anneals it might lose texture, as inferred seismically. The 2010 study hypothesized that the alloys recrystallized rather than coarsened via diffusion due to the very low solubility of Sn in the Zn-rich phase. This study tests this hypothesis by annealing directionally solidified hcp Zn-rich Al alloys, in which there is greater solubility. Indeed, we find the Zn-rich Al alloys coarsen without recrystallization or fundamental change in texture. However, in contrast to the 2010 study the current study also did not find recrystallization in Zn-rich Sn alloys. This might tend to support models such as those by Cormier (2007) and Aubert et al. (2008) where long term mantle control over fluid flow near the base of the outer core might result in a weaker solidification texture in the eastern hemisphere. Although we do believe the results of the previous study are valid because they were repeatable at that time, it shows that there is something subtle that we cannot yet account for, and it remains unclear whether there is loss of solidification texture due to annealing of Earth’s inner core.

  11. The interpretation of crustal dynamics data in terms of plate motions and regional deformation near plate boundaries

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.

    1991-01-01

    During our participation in the NASA Crustal Dynamics Project under NASA contract NAS-27339 and grant NAG5-814 for the period 1982-1991, we published or submitted for publication 30 research papers and 52 abstracts of presentations at scientific meetings. In addition, five M.I.T. Ph.D. students (Eric Bergman, Steven Bratt, Dan Davis, Jeanne Sauber, Anne Sheehan) were supported wholly or in part by this project during their thesis research. Highlights of our research progress during this period include the following: application of geodetic data to determine rates of strain in the Mojave block and in central California and to clarify the relation of such strain to the San Andreas fault and Pacific-North American plate motions; application of geodetic data to infer post seismic deformation associated with large earthquakes in the Imperial Valley, Hebgen Lake, Argentina, and Chile; determination of the state of stress in oceanic lithosphere from a systematic study of the centroid depths and source mechanisms of oceanic intraplate earthquakes; development of models for the state of stress in young oceanic regions arising from the differential cooling of the lithosphere; determination of the depth extent and rupture characteristics of oceanic transform earthquakes; improved determination of earthquake slip vectors in the Gulf of California, an important data set for the estimation of Pacific-North American plate motions; development of models for the state of stress and mechanics of fold-and-thrust belts and accretionary wedges; development of procedures to invert geoid height, residual bathymetry, and differential body wave travel time residuals for lateral variations in the characteristic temperature and bulk composition of the oceanic upper mantle; and initial GPS measurements of crustal deformation associated with the Imperial-Cerro Prieto fault system in southern California and northern Mexico. Full descriptions of the research conducted on these topics may be

  12. Metabolic neutrality of perindopril: focus on insulin sensitivity in overweight patients with essential hypertension.

    PubMed

    Böhlen, L; Bienz, R; Doser, M; Papiri, M; Shaw, S; Riesen, W; Weidmann, P

    1996-06-01

    To assess the effects of antihypertensive treatment with the angiotensin-converting enzyme (ACE) inhibitor perindopril on insulin sensitivity, plasma insulin, and lipoprotein metabolism in overweight hypertensive patients, we measured the insulin sensitivity index (SI, determined according to the minimal model method of Bergman), fasting plasma insulin and glucose concentrations, serum total triglyceride and lipoprotein cholesterol fractions, and blood pressure (BP) in 30 overweight [mean body mass index (BMI) 30.9 kg/m2], nondiabetic patients with essential hypertension after a 4-week run-in period and after 6 weeks of perindopril (n = 20) or placebo (n = 10) administered in a double-blind fashion. Furthermore, we estimated their state of physical fitness using the Conconi bicycle ergometer test before and after perindopril or placebo administration. SI was low in our study population (3.2 vs. 13.3 10(-4) ml.microU-1.min-1 in normal lean control subjects). It did not differ between the perindopril and placebo group after the placebo run-in period (3.1 vs. 3.3 x 10(-4) ml.microU-1.min-1) and was not influenced by perindopril (3.3 x 10(-4) ml.microU-1.min-1) or placebo (3.6 x 10(-4) ml.microU-1.min-1) treatment. Moreover, no significant changes were apparent in fasting plasma insulin and glucose, the areas under the glucose and insulin curves, the glucose disappearance rates, serum total triglycerides (TG), or cholesterol or lipoprotein cholesterol fractions between run-in and active treatment phases in the perindopril or the placebo group, respectively. Heart rate (HR), body weight, and anaerobic threshold remained stable in both groups. Compliance, assessed by pill counting was > 90% in both groups at all visits. Therefore, the ACE inhibitor perindopril is neutral with regard to insulin sensitivity, plasma insulin and glucose, and lipoprotein metabolism in overweight, nondiabetic patients with essential hypertension.

  13. Effects of chronic buspirone treatment on cocaine self-administration.

    PubMed

    Mello, Nancy K; Fivel, Peter A; Kohut, Stephen J; Bergman, Jack

    2013-02-01

    Cocaine abuse and dependence is a major public health problem that continues to challenge medication-based treatment. Buspirone (Buspar) is a clinically available, non-benzodiazepine anxiolytic medication that acts on both serotonin and dopamine systems. In recent preclinical studies, acute buspirone treatment reduced cocaine self-administration at doses that did not also decrease food-reinforced behavior in rhesus monkeys (Bergman et al, 2012). The present study evaluated the effectiveness of chronic buspirone treatment on self-administration of cocaine and food. Five adult rhesus monkeys (Macaca mulatta) were trained to self-administer cocaine and food during four 1-h daily sessions under a second-order schedule of reinforcement (FR2 [VR 16:S]). Buspirone (0.32 and 0.56 mg/kg/h) was administered intravenously through one lumen of a double-lumen catheter every 20 min for 23 h each day for 7-10 consecutive days. Each buspirone treatment period was followed by saline control treatment until drug- and food-maintained responding returned to baseline levels. Buspirone significantly reduced responding maintained by cocaine, and shifted the dose-effect curve downwards. Buspirone had minimal effects on food-maintained responding. In cocaine discrimination studies, buspirone (0.1-0.32 mg/kg, IM) did not antagonize the discriminative stimulus and rate-altering effects of cocaine in four of six monkeys. These findings indicate that buspirone selectively attenuates the reinforcing effects of cocaine in a nonhuman primate model of cocaine self-administration, and has variable effects on cocaine discrimination. PMID:23072835

  14. [Repeatability of insulin sensitivity estimation using the Minimal Model and comparison with a modified short low-dose insulin tolerance test].

    PubMed

    Rey, R H; Masnatta, L D; Pirola, D; Cuniberti, L A; Maceira, C; Werba, J P

    1996-01-01

    Hyperinsulinemia and insulin-resistance are metabolic disturbances associated with obesity, essential hypertension, hypertriglyceridemia, glucose intolerance, overt non-insulin dependent diabetes mellitus, polymetabolic syndrome and atherosclerotic disease. The assessment of in vivo insulin sensitivity (SAI in vivo) changes achieved by life style modifications or drug interventions require a reproducible technique. To evaluate the day-to-day intra-individual repeatability of SAI-in vivo, we determined the variation in the SI index (calculated from the Minimal Model of Bergman modified by insulin or MMins) in 11 subjects with a wide range of insulin-resistance. SI (first study) varied from 0.82 to 8.48 x 10(-4) min-1/microU.mL (4.43 +/- 2.85 x 10(-4) min-1/microU.mL mean +/- SD) and highly correlated with SI (second study) (r = 0.89; p = 0.0002). The average interday coefficient of variation was 20.9 +/- 13.9% and was similar in subjects with low or high SI values. We also measured SAI in vivo by assessing the rate of serum glucose decline induced by human cristalline insulin 0.025 U/kg IV dose after a 12-14 hours fasting period (a modified Bonora's method or BBD) in 11 subjects. No subject presented biochemical or symptomatic hypoglycemia. SAI in vivo values determined by BBD varied from 21 a 234 mumol/ml/min (134 +/- 64.8 mumol/ml/min, mean +/- SD). We found a highly significant correlation between SI values obtained from MMins and SAI in vivo assessed by the BBD (r = 0.89, p = 0.0002). Our results suggest that the Mmins is a fairly reproducible procedure and that a BBD is an acceptable option to quantify SAI in vivo, mainly when a fast-execution practice is necessary or cost restrictions are required.

  15. Iron diffusion from first principles calculations

    NASA Astrophysics Data System (ADS)

    Wann, E.; Ammann, M. W.; Vocadlo, L.; Wood, I. G.; Lord, O. T.; Brodholt, J. P.; Dobson, D. P.

    2013-12-01

    Research 116, B04307 (2011). 3. Buffett, B. A. Onset and orientation of convection in the inner core. Geophysical Journal International 179, 711-719 (2009). 4. Bergman, M. Measurements of electric anisotropy due to solidification texturing and the implications for the Earth's inner core. Nature 389, 60-63 (1997). 5. Deguen, R. & Cardin, P. Thermochemical convection in Earth's inner core. Geophysical Journal International 187, 1101-1118 (2011). 6. Reaman, D. M., Daehn, G. S. & Panero, W. R. Predictive mechanism for anisotropy development in the Earth's inner core. Earth and Planetary Science Letters 312, 437-442 (2011). 7. Ammann, M. W., Brodholt, J. P., Wookey, J. & Dobson, D. P. First-principles constraints on diffusion in lower-mantle minerals and a weak D'' layer. Nature 465, 462-5 (2010).

  16. Co-evolution of Eukaryotes and Ocean and Atmosphere Oxygenation in the Neoproterozoic and Paleozoic Eras

    NASA Astrophysics Data System (ADS)

    Lenton, T. M.; Daines, S. J.; Mills, B.; Boyle, R. A.

    2014-12-01

    producing a persistent, global oxygenation of the deep ocean [3]. Thus, the Earth's protracted second oxygenation event culminated in the Paleozoic not the Neoproterozoic. [1] Lenton et al. (2014) Nature Geoscience 7, 257-265 [2] Boyle et al. (2014) Nature Geoscience 7, 10.1038/NGEO2213 [3] Bergman et al. (2004) Am. J. Sci. 304, 397-437

  17. Venus

    NASA Astrophysics Data System (ADS)

    Fegley, B., Jr.

    2003-12-01

    Venus is Earth's nearest planetary neighbor, and has fascinated mankind since the dawn of history. Venus' clouds reflect most of the sunlight shining on the planet and make it the brightest object in the sky after the Sun and Moon. Venus is visible with the naked eye as an evening star until a few hours after sunset, or as a morning star shortly before sunrise. Many ancient civilizations observed and worshipped Venus, which had a different name in each society, e.g., Ishtar to the Babylonians, Aphrodite to the Greeks, Tai'pei to the Chinese, and Venus to the Romans (Hunt and Moore, 1982). Venus has continued to play an important role in myth, literature, and science throughout history. In the early seventeenth century, Galileo's observations of the phases of Venus showed that the geocentric (Ptolemaic) model of the solar system was wrong and that the heliocentric (Copernican) model was correct. About a century later, Edmund Halley proposed that the distance from the Earth to the Sun (which was then unknown and is defined as one astronomical unit, AU) could be measured by observing transits of Venus across the Sun. These transits occur in pairs separated by eight years at intervals of 105.5 yr and 121.5 yr in an overall cycle of 243 yr, e.g., June 6, 1761, June 3, 1769; December 9, 1874, December 6, 1882, June 8, 2004, June 6, 2012, December 11, 2117, and December 8, 2125. The first attempted measurements of the astronomical unit during the 1761 transit were unsuccessful. However, several observers reported a halo around Venus as it entered and exited the Sun's disk. Thomas Bergman in Uppsala and Mikhail Lomonosov in St. Petersburg, independently speculated that the halo was due to an atmosphere on Venus. Eight years later observations of the 1769 solar transit (including those made by Captain Cook's expedition to Tahiti) gave a value of 1 AU=153 million kilometers, ~2.3% larger than the actual size (149.6 million kilometers) of the astronomical unit (Woolf, 1959

  18. Stress in the Indo-Australian plate

    NASA Astrophysics Data System (ADS)

    Cloetingh, Sierd; Wortel, Rinus

    1986-12-01

    We modelled the state of stress in the Indo-Australian plate in order to investigate quantitatively variations observed in tectonic style. The numerical procedure incorporates the dependence of slab pull and ridge push on the age of the oceanic lithosphere. Estimates are presented for the average net resistive forces at the Himalayan collision zone, the suction force acting on the overriding Indo-Australian plate segment at the Tonga-Kermadec trench and the drag at the base of the lithosphere. Our modelling shows a concentration of compressive stresses of the order of 3-5 kbar in the Ninetyeast Ridge area; the effects of the compressive resistance associated with Himalayan collision and subduction of young lithosphere off the northern part of the Sunda arc are focused in this region. The stress field as calculated gives a consistent explanation for the observed concentration of seismic activity (Stein and Okal, 1978) and significant deformation in the oceanic crust (Weissel et al., 1980; McAdoo and Sandwell, 1985) in the area. The calculated stress field in the area adjacent to the Southeast and Central India ridges is characterized by tension parallel to the spreading axis. This explains the concentration of near-ridge normal faulting seismicity (with T-axes subparallel to the spreading ridge) in the Indian Ocean as recently observed by Bergman et al. (1984) and Wiens and Stein (1984). The regional stress field along the strike of the Sunda arc varies from compression seaward of and parallel to the Sumatra trench segment, to tension perpendicular to the Java-Flores segment. This explains the selective occurrence of well developed grabens seaward off the Java-Flores segment of the trench, observed by Hilde (1983). Our modelling shows that the observed rotation of the stress field (Denham et al., 1979) in the Australian continent is mainly the consequence of its geographic position relative to the surrounding trench segments and the variations of the forces acting

  19. Structure, stability, and electronic properties of the i -AlPdMn quasicrystalline surface

    NASA Astrophysics Data System (ADS)

    Krajčí, M.; Hafner, J.

    2005-02-01

    The structure, stability, and electronic properties of a fivefold surface of an icosahedral (i) Al-Pd-Mn alloy have been investigated using ab initio density-functional methods. Structural models for a series of rational approximants to the quasicrystalline structure of bulk i -AlPdMn have been constructed using the cut-and-projection technique with triacontahedral acceptance domains in the six-dimensional hyperspace according to the Katz-Gratias-Boudard model. This leads to a real-space structure describable in terms of interpenetrating Mackay and Bergman clusters. A fivefold surface has been prepared by cleaving the bulk structure along a plane perpendicular to a fivefold axis. The position of the cleavage plane has been chosen such as to produce a surface layer with a high atomic density. The atomic structure of these surfaces can be described by a P1 tiling by pentagons, thin rhombi, pentagonal stars, and a “boat”—in terms of a cut-and-projection model the decagonal acceptance domain of the P1 tiling corresponds to the maximal cross section of the triacontahedra defining the three-dimensional quasicrystal. The vertices of the P1 tiling are occupied by Pd atoms surrounded by pentagonal motifs of Al atoms. For the ab initio calculations we have prepared slab models of the surface based on the 3/2 and 2/1 approximants and containing up to 357 atoms in the computational cell. The analysis of the surface charge density shows flat minima at the vertices of the P1 tiling and strong charge depletion in some of the pentagonal tiles (“surface vacancies”). Both observations are in agreement with scanning tunneling microscopy studies of these surfaces. Structural relaxations have been performed only for the 2/1 models with up to 205 atoms/cell. The calculations demonstrate that the skeleton of the P1 tiling fixed by the transition-metal atoms represents a stable surface termination, but considerable rearrangement of the Al atoms and large relaxations of the

  20. Naltrexone effects on insulin sensitivity and insulin secretion in hyperandrogenic women.

    PubMed

    Sir-Petermann, T; López, G; Castillo, T; Calvillán, M; Rabenbauer, B; Wildt, L

    1998-01-01

    A total of 12 women (24.2 +/- 1.6 years old, BMI 36.7 +/- 1.5 Kg/m2) with hyperandrogenism (HA) and with normal glucose tolerance test were studied to evaluate the involvement of endogenous opioids in the pathophysiology of insulin secretion and insulin sensitivity in HA by administering naltrexone, an oral opioid receptor antagonist. Six patients received naltrexone orally (75 mg daily) and another six received placebo for 12 weeks (double-blind study). Before and after therapy a frequently sampled intravenous glucose tolerance test (FSIVGTT) was performed. The insulin sensitivity index (SI) was determined by Bergman's program. SHBG, DHEAS, testosterone, free androgen index (FAI) and plasma concentrations of IGF-I and IGFBP-1 were determined in 3 basal samples, before and after therapy. Treatment with naltrexone in hyperandrogenic patients resulted in a decrease in fasting insulin concentrations of 40% and C-peptide concentrations of 50% (p < 0.05). Insulin and C-peptide from the FSIVGTT displayed a similar pattern with a fall in the area under the curve under naltrexone treatment of 34% for insulin and 35% for C-peptide. Insulin sensitivity did not change under naltrexone (1.26 +/- 0.19 vs 1.32 +/- 0.32 10(-4) x min(-1)/(uU/ml)) or placebo (0.95 +/- 0.19 vs 1.12 +/- 0.28 10(-4) x min(-1)/(uU/ml)) administration. However, glucose effectiveness increased significantly with naltrexone (2.231 +/- 0.002 vs 3.354 +/- 0.006 x 10(-2) min(-1)). Glucose (fasting and area under the curve) was not modified significantly after naltrexone administration. Baseline hormone levels were similar in the two groups, and they did not change after long-term treatment with naltrexone or placebo. In conclusion, these results support the hypothesis of elevated opioid tonus and increased insulin secretion as a possible mechanism of hyperinsulinism in a group of hyperandrogenic women of ovarian origin. This alteration could act as an additional factor in the pathogenesis of insulin

  1. Polyclusters and substitution effects in the Na-Au-Ga system: remarkable sodium bonding characteristics in polar intermetallics.

    PubMed

    Smetana, Volodymyr; Miller, Gordon J; Corbett, John D

    2013-11-01

    A systematic exploration of Na- and Au-poor parts of the Na-Au-Ga system (less than 15 at. % Na or Au) uncovered several compounds with novel structural features that are unusual for the rest of the system. Four ternary compounds Na1.00(3)Au0.18Ga1.82(1) (I), NaAu2Ga4 (II), Na5Au10Ga16 (III), and NaAu4Ga2 (IV) have been synthesized and structurally characterized by single crystal X-ray diffraction: Na1.00(3)Au0.18Ga1.82(1)(I, P6/mmm, a = 15.181(2), c =9.129(2)Å, Z = 30); NaAu2Ga4 (II, Pnma, a = 16.733(3), b = 4.3330(9), c =7.358(3) Å, Z = 4); Na5Au10Ga16 (III, P6(3)/m, a = 10.754(2), c =11.457(2) Å, Z = 2); and NaAu4Ga2 (IV, P2(1)/c, a = 8.292(2), b = 7.361(1), c =9.220(2)Å, β = 116.15(3), Z = 4). Compound I lies between the large family of Bergman-related compounds and Na-poor Zintl-type compounds and exhibits a clathrate-like structure containing icosahedral clusters similar to those in cubic 1/1 approximants, as well as tunnels with highly disordered cation positions and fused Na-centered clusters. Structures II, III, and IV are built of polyanionic networks and clusters that generate novel tunnels in each that contain isolated, ordered Na atoms. Tight-binding electronic structure calculations using linear muffin-tin-orbital (LMTO) methods on II, III, IV and an idealized model of I show that all are metallic with evident pseudogaps at the Fermi levels. The integrated crystal orbital Hamilton populations for II-IV are typically dominated by Au-Ga, Ga-Ga, and Au-Au bonding, although Na-Au and Na-Ga contributions are also significant. Sodium's involvement into such covalency is consistent with that recently reported in Na-Au-M (M = Ga, Ge, Sn, Zn, and Cd) phases.

  2. Panoscopically optimized thermoelectric performance of a half-Heusler/full-Heusler based in situ bulk composite Zr(0.7)Hf(0.3)Ni(1+x)Sn: an energy and time efficient way.

    PubMed

    Bhardwaj, A; Chauhan, N S; Sancheti, Bhagyashree; Pandey, G N; Senguttuvan, T D; Misra, D K

    2015-11-28

    All scale hierarchical architecturing, matrix/inclusion band alignment and intra-matrix electronic structure engineering, the so called panoscopic approach for thermoelectric materials has been demonstrated to be an effective paradigm for optimizing high ZT. To achieve such hierarchically organized microstructures, composition engineering has been considered to be an efficient strategy. In this work, such a panoscopic concept has been extended to demonstrate for the first time in the case of half-Heusler based thermoelectric materials via a composition engineering route. A series of new off-stoichiometric n-type Zr0.7Hf0.3Ni1+xSn (0 ≤x≤ 0.10) HH compositions have been modified to derive HH(1 -x)/full-Heusler (FH)(x) composite with an all scale hierarchically modified microstructure with FH inclusions within the matrix to study the temperature dependent thermoelectric properties. The structural analysis employing XRD, FE-SEM and HR-TEM of these materials reveal a composite of HH and FH, with hierarchically organized microstructures. In such a submicron/nano-composite, the electronic properties are observed to be well optimized yielding a large power factor; α(2)σ (∼30.7 × 10(-4) W m(-1) K(-2) for Zr0.7Hf0.3Ni1.03Sn) and reduced thermal conductivity (∼2.4 W m(-1) K(-1) for Zr0.7Hf0.3Ni1.03Sn) yielding a high ZT∼ 0.96 at 773 K for composition Zr0.7Hf0.3Ni1.03Sn which is ∼250% larger than the normal HH Zr0.7Hf0.3NiSn (ZT∼ 0.27 at 773 K). The enhancement in ZT of these composites has been discussed in terms of primary electron filtering, electron injection and several phonon scattering mechanisms such as alloy scattering, point defect scattering, and grain boundary scattering. The Bergman and Fel model is used to calculate effective thermoelectric parameters of these composites for comparing the experimental results. PMID:26499748

  3. [IMPACT OF DIETARY FATTY ACIDS ON LIPID PROFILE, INSULIN SENSITIVITY AND FUNCTIONALITY OF PANCREATIC β CELLS IN TYPE 2 DIABETIC SUBJECTS].

    PubMed

    Sambra Vásquez, Verónica; Rojas Moncada, Pamela; Basfi-Fer, Karen; Valencia, Alejandra; Codoceo, Juana; Inostroza, Jorge; Carrasco, Fernando; Ruz Ortiz, Manuel

    2015-09-01

    Introducción: la calidad de las grasas podría influir en el control metabólico de los sujetos con diabetes mellitus tipo 2 (DM2). Objetivos: determinar la relación entre la ingesta y la calidad de los ácidos grasos de la dieta con el perfil lipídico, el control metabólico, la funcionalidad de las células pancreáticas y la sensibilidad a la insulina en sujetos con DM2. Métodos: se estudió a 54 sujetos con DM2, se realizaron determinaciones antropométricas, de composición corporal e ingesta dietética de lípidos, ácidos grasos saturados (AGS), trans, monoinsaturados, poliinsaturados, omega 3, omega 6 y colesterol dietario. Se determinaron los parámetros de laboratorio relacionados con el control metabólico (glicemia de ayuno, hemoglobina glicada, perfil lipídico). La secreción de insulina y la sensibilidad a la insulina se determinaron con el test intravenoso de tolerancia a la glucosa modificado con insulina, basado en el modelo mínimo de Bergman. Resultados: se estudió a 28 hombres y 26 mujeres (edad 55,6 ± 6,8 años; IMC 29,5 ± 3,7 kg/m2). Un 48% presentaba c-LDL < 100 mg/dl, el 12,9% de los hombres c-HDL > 40 mg/dl y el 7,4% de las mujeres c-HDL > 50 mg/dl. El 32% consumía > 10% de AGS y > 300 mg/día de colesterol dietario. La ingesta de AGS y el porcentaje de calorías grasas (G%) mostraron una asociación positiva significativa con la resistencia a la insulina y la glicemia. El G% predice en un 84% la variabilidad del c-VLDL. Conclusiones: en los sujetos con DM2, una mayor ingesta de AGS y de grasas se asocia con valores superiores de glicemia y de resistencia a la insulina.

  4. Panoscopically optimized thermoelectric performance of a half-Heusler/full-Heusler based in situ bulk composite Zr(0.7)Hf(0.3)Ni(1+x)Sn: an energy and time efficient way.

    PubMed

    Bhardwaj, A; Chauhan, N S; Sancheti, Bhagyashree; Pandey, G N; Senguttuvan, T D; Misra, D K

    2015-11-28

    All scale hierarchical architecturing, matrix/inclusion band alignment and intra-matrix electronic structure engineering, the so called panoscopic approach for thermoelectric materials has been demonstrated to be an effective paradigm for optimizing high ZT. To achieve such hierarchically organized microstructures, composition engineering has been considered to be an efficient strategy. In this work, such a panoscopic concept has been extended to demonstrate for the first time in the case of half-Heusler based thermoelectric materials via a composition engineering route. A series of new off-stoichiometric n-type Zr0.7Hf0.3Ni1+xSn (0 ≤x≤ 0.10) HH compositions have been modified to derive HH(1 -x)/full-Heusler (FH)(x) composite with an all scale hierarchically modified microstructure with FH inclusions within the matrix to study the temperature dependent thermoelectric properties. The structural analysis employing XRD, FE-SEM and HR-TEM of these materials reveal a composite of HH and FH, with hierarchically organized microstructures. In such a submicron/nano-composite, the electronic properties are observed to be well optimized yielding a large power factor; α(2)σ (∼30.7 × 10(-4) W m(-1) K(-2) for Zr0.7Hf0.3Ni1.03Sn) and reduced thermal conductivity (∼2.4 W m(-1) K(-1) for Zr0.7Hf0.3Ni1.03Sn) yielding a high ZT∼ 0.96 at 773 K for composition Zr0.7Hf0.3Ni1.03Sn which is ∼250% larger than the normal HH Zr0.7Hf0.3NiSn (ZT∼ 0.27 at 773 K). The enhancement in ZT of these composites has been discussed in terms of primary electron filtering, electron injection and several phonon scattering mechanisms such as alloy scattering, point defect scattering, and grain boundary scattering. The Bergman and Fel model is used to calculate effective thermoelectric parameters of these composites for comparing the experimental results.

  5. E-Waste and Harm to Vulnerable Populations: A Growing Global Problem

    PubMed Central

    Heacock, Michelle; Kelly, Carol Bain; Asante, Kwadwo Ansong; Birnbaum, Linda S.; Bergman, Åke Lennart; Bruné, Marie-Noel; Buka, Irena; Carpenter, David O.; Chen, Aimin; Huo, Xia; Kamel, Mostafa; Landrigan, Philip J.; Magalini, Federico; Diaz-Barriga, Fernando; Neira, Maria; Omar, Magdy; Pascale, Antonio; Ruchirawat, Mathuros; Sly, Leith; Sly, Peter D.; Van den Berg, Martin; Suk, William A.

    2015-01-01

    Background: Electronic waste (e-waste) is produced in staggering quantities, estimated globally to be 41.8 million tonnes in 2014. Informal e-waste recycling is a source of much-needed income in many low- to middle-income countries. However, its handling and disposal in underdeveloped countries is often unsafe and leads to contaminated environments. Rudimentary and uncontrolled processing methods often result in substantial harmful chemical exposures among vulnerable populations, including women and children. E-waste hazards have not yet received the attention they deserve in research and public health agendas. Objectives: We provide an overview of the scale and health risks. We review international efforts concerned with environmental hazards, especially affecting children, as a preface to presenting next steps in addressing health issues stemming from the global e-waste problem. Discussion: The e-waste problem has been building for decades. Increased observation of adverse health effects from e-waste sites calls for protecting human health and the environment from e-waste contamination. Even if e-waste exposure intervention and prevention efforts are implemented, legacy contamination will remain, necessitating increased awareness of e-waste as a major environmental health threat. Conclusion: Global, national, and local levels efforts must aim to create safe recycling operations that consider broad security issues for people who rely on e-waste processing for survival. Paramount to these efforts is reducing pregnant women and children’s e-waste exposures to mitigate harmful health effects. With human environmental health in mind, novel dismantling methods and remediation technologies and intervention practices are needed to protect communities. Citation: Heacock M, Kelly CB, Asante KA, Birnbaum LS, Bergman AL, Bruné MN, Buka I, Carpenter DO, Chen A, Huo X, Kamel M, Landrigan PJ, Magalini F, Diaz-Barriga F, Neira M, Omar M, Pascale A, Ruchirawat M, Sly L, Sly PD

  6. A Global Record of Surface Earth Oxygenation from Sedimentary V/Sc

    NASA Astrophysics Data System (ADS)

    Keller, C. B.; Schoene, B.; Johnston, D. T.

    2015-12-01

    One of the simplest methods to investigate changes in oxidation potential in geologic environments is to examine a pair of otherwise similar elements with dramatically different redox chemistry. The first-row transition metals Sc and V represent one such pair, with generally similar mass, radius, and ionization energies up to the trivalent redox state. However, as a d3 transition metal, Sc is limited to a maximum oxidation state of 3+, while d5 vanadium may be further oxidized to form tetravalent and pentavalent ions. Due to the greater incompatibility of pentavalent (relative to trivalent) metal cations in silicate melts, V/Sc ratio has been applied to the silicate rock record as a tracer of magma redox - indicating roughly constant mantle oxygen fugacity over Earth history1,2. As a result, the solid earth represents a boundary condition with constant V/Sc observed over geologic time1. However, oxidation state also affects the weathering, solubility, and coordination behaviour of V and Sc, resulting in a potential redox signal in the sedimentary V/Sc record. We apply the weighted bootstrap resampling approach of [2] to a geochemical dataset of ~87,000 sedimentary whole-rock analyses from the EarthChem portal3. The resulting trends reveal a 4 Gyr record of V/Sc redox chemistry, with the great oxidation event represented as an upward step ca. 2.5 Ga, and Phanerozoic variation suggestive of low oxygen in the early Paleozoic, increasing to twin maxima circa 270 Ma and 130 Ma, remarkably similar to that predicted by the COPSE model4, and broadly congruent with the Phanerozoic biochar record5. Li, Z.-X. A. & Lee, C.-T. A. EPSL 228, 483-493 (2004). Keller, C. B. & Schoene, B. Nature 485, 490-493 (2012). EarthChem Bergman, N. M. Am. J. Science 304, 397-437 (2004). Glasspool, I. J. & Scott, A. C. Nat. Geosci. 3, 627-630 (2010).

  7. Towards a coherent interpretation of the seismic inner core

    NASA Astrophysics Data System (ADS)

    Alboussiere, T.; Deguen, R.

    2012-12-01

    Research, 101, 1996 [4] M. Bergman et al., Geophysical Research Letters, 37, 2010

  8. PREFACE: Continuum Models and Discrete Systems Symposia (CMDS-12)

    NASA Astrophysics Data System (ADS)

    Chakrabarti, Bikas K.

    2011-09-01

    The 12th International Symposium on Continuum Models and Discrete Systems (CMDS-12) (http://www.saha.ac.in/cmp/cmds.12/) took place at the Saha Institute of Nuclear Physics in Kolkata from 21-25 February 2011. Previous CMDS symposia were held in Kielce (Poland, 1975), Mont Gabriel (Canada, 1977), Freudenstadt (Federal Republic of Germany, 1979), Stockholm (Sweden, 1981), Nottingham (United Kingdom, 1985), Dijon (France, 1989), Paderborn (Germany, 1992), Varna (Bulgaria, 1995), Istanbul (Turkey, 1998), Shoresh (Israel, 2003) and Paris (France, 2007). The broad interdisciplinary character, limited number of participants (not exceeding 100) and informal and friendly atmosphere of these meetings has made them a well-acknowledged place to make highly fruitful contacts and exchange ideas, methods and results. The purpose of CMDS is to bring together scientists with different backgrounds who work on continuum theories of discrete mechanical and thermodynamical systems in the fields of mathematics, theoretical and applied mechanics, physics, material science, and engineering. The spirit of the CMDS meetings is to stimulate extensive and active interdisciplinary research. The International Scientific Committee members of this conference were: David J Bergman (Chairman CMDS 10), Tel Aviv University, Israel; Bikas K Chakrabarti (Chairman CMDS 12), Saha Institute of Nuclear Physics, India; Alex Hansen, Norwegian University of Science and Technology, Norway; Hans Jürgen Herrmann, Institute for Building Materials, ETH, Switzerland; Esin Inan (Chairman CMDS 9), Istanbul Technical University, Turkey; Dominique Jeulin (Chairman CMDS 11), Ecole des Mines de Paris, France; Frank Juelicher, Max-Planck-Institute for the Physics of Complex Systems, Germany; Hikaru Kawamura, University of Osaka, Japan; Graeme Milton, University of Utah, USA; Natalia Movchan, University of Liverpool, UK; and Ping Sheng, The Hong Kong University of Science and Technology, Hong Kong. At CMDS-12 the topics

  9. PREFACE: Multiferroics Multiferroics

    NASA Astrophysics Data System (ADS)

    Loidl, Alois; von Loehneysen, Hilbert; Kalvius, G. Michael

    2008-10-01

    stimulate and trigger further important contributions in experimental exploration and theoretical concepts. References [1] Hill N A 2000 J. Phys. Chem. B 104 6694-709 [2] Khomskii D I and Bull A 2001 Phys. Soc. C 21 2 Khomskii D I 2006 J. Magn. Magn. Mater. 306 1 [3] Smoleskii G A, Agranovskaia A I, Popov S N and Isupov V A 1958 Sov. Phys. Tech. Phys. 3 1981 [4] Smolenskii G A and Chupis I E 1974 Sov. Phys. Usp. 25 475 [5] Wood V E and Austin A E 1974 Int. J. Magnetism 5 303 [6] Kimura T, Goto T, Shintani H, Ishizaka K, Arima T and Tokura Y 2003 Nature 426 55 [7] Hur N, Park S, Sharma P A, Ahn J S, Guha S, Cheong S-W 2004 Nature 429 392 [8] Lawes G, Harris A B, Kimura T, Rogado N, Cava R J, Aharony A, Entin-Wohlmann O, Yildirim T, Kenzelmann M, Broholm C and Ramirez A P 2005 Phys. Rev. Lett. 95 087205

  10. Nanomaterials in Space: is the Future Granted?

    NASA Astrophysics Data System (ADS)

    Mircea, Chipara

    effects of radiation on solid targets, at the nanometer scale, to extend previous calculations in order to include higher order effects, and finally to understand and if it is possible to protect these nanometer sized structures or to design nanometer sized structures that are less significantly affected by the space environment. As a final warning, a recent paper [4] mentioned that the under the effect of ion beam bombardment the nanocrystalline zirconia has been transformed in an amorphous material. References: [1]. A. Aharoni, Introduction to the Theory of Ferromagnetism, Oxford University Press, Oxford, 1996. [2]. M. Chipara, R. Skomski, D. J. Sellmyer, J. Magn. Magn. Mat. to appear. [3]. Irradiation of Polymers: Fundamentals and Technological Applications, Edited by Roger L. Clough, S. W. Shalaby, [4] A. Meldrum, L. A. Boatner, R. C. Ewing, Phys. Rev. Lett, 88, 025503-1 (2002).

  11. Caries management pathways preserve dental tissues and promote oral health.

    PubMed

    Ismail, Amid I; Tellez, Marisol; Pitts, Nigel B; Ekstrand, Kim R; Ricketts, David; Longbottom, Christopher; Eggertsson, Hafsteinn; Deery, Christopher; Fisher, Julian; Young, Douglas A; Featherstone, John D B; Evans, Wendell; Zeller, Gregory G; Zero, Domenick; Martignon, Stefania; Fontana, Margherita; Zandona, Andrea

    2013-02-01

    In May 2012, cariologists, dentists, representatives of dental organizations, manufacturers, and third party payers from several countries, met in Philadelphia, Pennsylvania, to define a common mission; goals and strategic approaches for caries management in the 21th century. The workshop started with an address by Mr. Stanley Bergman, CEO of Henry Schein Inc. which focused on the imperative for change in academia, clinical practice, and public health. For decades, new scientific evidence on caries and how it should be managed have been discussed among experts in the field. However, there has been some limited change, except in some Scandinavian countries, in the models of caries management and reimbursement which have been heavily skewed toward 'drilling and filling'. There is no overall agreement on a caries' case definition or on when to surgically intervene. The participants in the workshop defined a new mission for all caries management approaches, both conventional and new. The mission of each system should be to preserve the tooth structure, and restore only when necessary. This mission marks a pivotal line for judging when to surgically intervene and when to arrest or remineralize early noncavitated lesions. Even when restorative care is necessary, the removal of hard tissues should be lesion-focused and aim to preserve, as much as possible, sound tooth structure. Continuing management of the etiological factors of caries and the use of science-based preventive regimens also will be required to prevent recurrence and re-restoration. These changes have been debated for over a decade. The Caries Management Pathways includes all systems and philosophies, conventional and new, of caries management that can be used or modified to achieve the new mission. The choice of which system to use to achieve the mission of caries management is left to the users and should be based on the science supporting each approach or philosophy, experience, utility, and ease of use

  12. Efficiency of preventive actions for landslides and flooding - evaluation of Scandinavian practices

    NASA Astrophysics Data System (ADS)

    Bergman, R.; Andersson-sköld, Y. B.; Nyberg, L.; Johansson, M.; Persson, E.

    2011-12-01

    Author: Ramona Bergman, Yvonne Andersson-Sköld, Lars Nyberg, Magnus Johansson, Erik Persson Preventive actions can be, and are frequently, taken to reduce accidents and their consequences in different ways. The MSB funded research programme "Effects of Society's Security actions" (ESS, 2009-2013) aims to study the relationship between such actions and their effects. The program is divided into three subgroups: Frequent accidents Natural hazards (such as flooding, erosion and landslide) Chemical and landfill accidents The results presented here covers natural hazards with focus on land slides and flooding. The results are based on Swedish/Scandinavian contexts. Natural events such as erosion, flooding and land slides are common, but the number of accidents (events causing severe negative impact) is rare. Therefore, in such analysis there is limited data and other information available which can be used for example in statistical analysis of actions and their effects. Instead, the analysis must be based on other information. Therefore, the analysis may have to include aspects that only can be assessed by scenario and "what-if" analyses. In this project the main method has been interviews with officials in Swedish municipalities and national agencies in Sweden and Norway. The two levels are chosen since policies are taken on national (or international) level, while the key actions and actors are on the municipal level. The interviews cover experiences and potential scenarios. In all municipalities, one politician and officials working with planning and rescue service have been interviewed. The study covers hazard and risk mapping, follow up of such maps, physical planning and lessons learned from previous events and activities. The final outcome of the research will be a review of what is found to be well functioning, identification of weak points and recommendations for the management of landslides, erosion and flooding. The present results indicate that hazard

  13. Laboratory Study of O2(b1Σ g+, υ = 1) Collisional Removal at Thermospheric Temperatures

    NASA Astrophysics Data System (ADS)

    Wouters, E. R.; Pejaković, D. A.; Phillips, K. E.; Kalogerakis, K. S.

    2003-12-01

    NSF's Research Experiences for Undergraduates (REU) Program (Grant PHY-0097861). We wish to thank Drs. Richard A. Copeland and Tom G. Slanger for many insightful comments and discussions. 1. H. I. Bloemink, R. A. Copeland, and T. G. Slanger, J. Chem. Phys. 109, 4237 (1998). 2. E. S. Hwang, A. Bergman, R. A. Copeland, and T. G. Slanger, J. Chem. Phys. 110, 18 (1999).

  14. Proton Mediated Chemistry and Catalysis in a Self-Assembled Supramolecular Host

    SciTech Connect

    Pluth, Michael; Bergman, Robert; Raymond, Kenneth

    2009-04-10

    Synthetic supramolecular host assemblies can impart unique reactivity to encapsulated guest molecules. Synthetic host molecules have been developed to carry out complex reactions within their cavities, despite the fact that they lack the type of specifically tailored functional groups normally located in the analogous active sites of enzymes. Over the past decade, the Raymond group has developed a series of self-assembled supramolecules and the Bergman group has developed and studied a number of catalytic transformations. In this Account, we detail recent collaborative work between these two groups, focusing on chemical catalysis stemming from the encapsulation of protonated guests and expanding to acid catalysis in basic solution. We initially investigated the ability of a water-soluble, self-assembled supramolecular host molecule to encapsulate protonated guests in its hydrophobic core. Our study of encapsulated protonated amines revealed rich host-guest chemistry. We established that self-exchange (that is, in-out guest movement) rates of protonated amines were dependent on the steric bulk of the amine rather than its basicity. The host molecule has purely rotational tetrahedral (T) symmetry, so guests with geminal N-methyl groups (and their attendant mirror plane) were effectively desymmetrized; this allowed for the observation and quantification of the barriers for nitrogen inversion followed by bond rotation. Furthermore, small nitrogen heterocycles, such as N-alkylaziridines, N-alkylazetidines, and N-alkylpyrrolidines, were found to be encapsulated as proton-bound homodimers or homotrimers. We further investigated the thermodynamic stabilization of protonated amines, showing that encapsulation makes the amines more basic in the cavity. Encapsulation raises the effective basicity of protonated amines by up to 4.5 pK{sub a} units, a difference almost as large as that between the moderate and strong bases carbonate and hydroxide. The thermodynamic stabilization

  15. Operational earthquake forecasting in the South Iceland Seismic Zone: improving the earthquake catalogue

    NASA Astrophysics Data System (ADS)

    Panzera, Francesco; Vogfjörd, Kristin; Zechar, J. Douglas; Eberhard, David

    2014-05-01

    attenuation relations derived for earthquakes in Iceland (Pétursson and Vogfjörd, 2010) and use this relationship to address the problem of underestimating seismic moment for larger earthquakes (>3.0). Finally, to solve the problem related with the overestimation of aftershock magnitude of large earthquakes about 150 earthquakes were checked. All such passages demonstrate the importance of carefully checking the catalogue before proceeding with the operational earthquake forecasting. References Bondar, I., S.C. Myers, E.R. Engdahl, and E.A. Bergman (2004). Epicentre accuracy based on seismicnetwork criteria, Geophys. J. Int., 156, 483-496. Gomberg, J.S., K.M. Shedlock, and S.W. Roecker (1990). The effect of S-Wave arrival times on the accuracy of hypocenter estimation, Bull. Seism. Soc. Am., 80, 1605-1628. Pétursson and Vogfjörd (2010). Attenuation relations for near- and far field peak ground motion (PGV, PGA)and new magnitude estimatesfor large earthquakes in SW-Iceland. Report n° VI 2009-012, pp. 43, ISSN 1670-8261. Slunga, R., P. Norrman and A. Glans (1984). Seismicity of Southern Sweden - Stockholm: Försvarets Forskningsanstalt, July 1984. FOA Report, C2 C20543-T1, 106 p.

  16. The triple risk hypotheses in sudden infant death syndrome.

    PubMed

    Guntheroth, Warren G; Spiers, Philip S

    2002-11-01

    Sudden infant death syndrome (SIDS) victims were regarded as normal as a matter of definition (Beckwith 1970) until 1952 when Kinney and colleagues argued for elimination of the clause, "unexpected by history." They argued that "not all SIDS victims were normal," and referred to their hypothesis that SIDS results from brain abnormalities, which they postulated "to originate in utero and lead to sudden death during a vulnerable postnatal period." Bergman (1970) argued that SIDS did not depend on any "single characteristic that ordains a infant for death," but on an interaction of risk factors with variable probabilities. Wedgwood (1972) agreed and grouped risk factors into the first "triple risk hypothesis" consisting of general vulnerability, age-specific risks, and precipitating factors. Raring (1975), based on a bell-shaped curve of age of death (log-transformed), concluded that SIDS was a random process with multifactorial causation. Rognum and Saugstad (1993) developed a "fatal triangle" in 1993, with groupings similar to those of Wedgwood, but included mucosal immunity under a vulnerable developmental stage of the infant. Filiano and Kinney (1994) presented the best known triple risk hypothesis and emphasized prenatal injury of the brainstem. They added a qualifier, "in at least a subset of SIDS," but, the National Institute of Child Health and Development SIDS Strategic Plan 2000, quoting Kinney's work, states unequivocally that "SIDS is a developmental disorder. Its origins are during fetal development." Except for the emphasis on prenatal origin, all 3 triple risk hypotheses are similar. Interest in the brainstem of SIDS victims began with Naeye's 1976 report of astrogliosis in 50% of all victims. He concluded that these changes were caused by hypoxia and were not the cause of SIDS. He noted an absence of astrogliosis in some older SIDS victims, compatible with a single, terminal episode of hypoxia without previous hypoxic episodes, prenatal or postnatal

  17. Scanning tuneeling microscopy studies of fivefold surfaces of icosahedral Al-Pd-Mn quasicrystals and of thin silver films on those surfaces

    SciTech Connect

    Unal, Baris

    2008-01-01

    their top planes. Hence, we name them as Pd+(with Pd) and Pd-(without Pd). Based on their planer structure and the step height, it can be said that these two families can be viable surface terminations. However, besides the Pd content, these two sets differ in terms of relative densities of their top planes as well as the gap separating the layer from the nearest atomic plane. The experimental data and other arguments lead to the conclusion that the Pd- family is favored over the Pd+. This has an important implication on the interpretation of local motifs seen in the high resolution STM images. In other words, the dark stars are not formed by cut-Bergmans rather they are formed by cut-Mackays.

  18. Cat herding on a global scale - the challenge of building a vocabulary for the geology of Europe with compatibility to a global ontology

    NASA Astrophysics Data System (ADS)

    Asch, Kristine

    2010-05-01

    to another question - Which classification should be adopted for the definition of "grain size": Wentworth (1922), Folk (1962), ISO 14688-1 (2003) or even another one? However, the quotation of F. J. Pettijohn (1975): "The classification of the sedimentary rocks is a problem on which much thought has been expended and one for which no mutually satisfactory or complete solution has yet been found" does not only apply to sedimentary rock types; there are numerous "bones of classication contentions" also for igneous and metamorphic rock types. Based on the vocabulary specification OneG-E will identify the generic and specific geometric and semantic harmonisation issues and will then "rework" these existing national datasets to make significant progress towards a harmonised dataset - a crucial step towards INSPIRE goals. The standards, architecture and framework developed here can then be "up-scaled" to more detailed levels and progressively deployed for higher resolution geological data. The work on the OneG-E data vocabulary is contributing to enrich and improve the global CGI vocabulary and ontology and will provide a solid base for the description of geology of each EC country when the EC INSPIRE Directive's specification is defined. References Asch, K., Bavec, M., Bergman, S., Perez Cerdan, F., Declercq, P.Y., Janjou, D., Kacer, S., Klicker, M., Nironen, M., Pantaloni, M., Schubert, C. (in preparation): OneGeology-Europe Scientific/Semantic Data Specification and - Generic Specification for Spatial Geological Data in Europe. ECP-2007-GEO-317001 Folk, R.L. (1962): Spectral subdivision of limestone types. In Ham, W.E., ed.: Classification of Carbonate Rocks - A Symposium. American Association of Petroleum Geologists Memoir 1: 62-84 ISO 14688-1 (2002): Geotechnical investigation and testing - Identification and classification of soil - Part 1: Identification and description Pettijohn, F.J. (1975): Sedimentary Rocks.- 3rd ed.; Harper & Row Publishers (New York, Evanston

  19. Screening of perfluorinated compounds in water, sediment and biota of the Llobregat River basin (NE Spain)

    NASA Astrophysics Data System (ADS)

    Campo, Julian; Perez, Francisca; Pico, Yolanda; Farre, Marinella; Barcelo, Damia; Andreu, Vicente

    2014-05-01

    compounds, 13 were identified in water samples (PFBA, PFDA, PFHpA, PFHxA, PFHxDA, PFNA, PFOA, PFPeA, PFTrDA, PFUdA, L-PFBS, L-PFHxS and L-PFOS), and their concentrations ranged between 0. 1 ng L-1 (PFNA) and 2709 ng L-1 (L-PFOS). Similarly, PFBA, PFDA, PFDoA, PFHpA, PFNA, PFOA, PFPeA, PFTrDA, PFUdA, L-PFBS, L-PFHxS, L-PFOS and PFOSA were identified in sediments samples, with concentrations ranging from 0.147 ng g-1 dw (L-PFOS) to 13 ng g-1 dw (PFBA). In biota similar PFC were detected, with values between 0.03 and 1738.06 ng g-1. According to this study, PFCs were detected in different compartments of the ecosystem where they are bio-accumulating and, potentially, would produce adverse effects on humans. Acknowledgements This work has been supported by the Spanish Ministry of Economy and Competitiveness through the projects Consolider-Ingenio 2010 CSD2009-00065 and CGL2011-29703-C02-02. We also thank the persons of IDAEA for taking the samples. References Llorca, M., Farre, M., Pico, Y., Muller, J., Knepper, T. P., Barcelo, D., 2012. Analysis of perfluoroalkyl substances in waters from Germany and Spain. Sci. Total Environ. 431, 139-150. Llorca, M., Pérez, F., Farre, M., Agramunt, S., Kogevinas, M., Barceló, D., 2012. Analysis of perfluoroalkyl substances in cord blood by turbulent flow chromatography coupled to tandem mass spectrometry. Sci. Total Environ. 433, 151-160. Pico, Y., Blasco, C., Farre, M., Barcelo, D., 2012. Occurrence of perfluorinated compounds in water and sediment of L'Albufera Natural Park (Valencia, Spain). Environ.Sci.Pollut.Res. 19, 946-957. Sundstrom, M., Ehresman, D. J., Bignert, A., Butenhoff, J. L., Olsen, G. W., Chang, S. C., Bergman, A., 2011. A temporal trend study (1972-2008) of perfluorooctanesulfonate, perfluorohexanesulfonate, and perfluorooctanoate in pooled human milk samples from Stockholm, Sweden. Environ. Inter. 37, 178-183.

  20. Cat herding on a global scale - the challenge of building a vocabulary for the geology of Europe with compatibility to a global ontology

    NASA Astrophysics Data System (ADS)

    Asch, Kristine

    2010-05-01

    to another question - Which classification should be adopted for the definition of "grain size": Wentworth (1922), Folk (1962), ISO 14688-1 (2003) or even another one? However, the quotation of F. J. Pettijohn (1975): "The classification of the sedimentary rocks is a problem on which much thought has been expended and one for which no mutually satisfactory or complete solution has yet been found" does not only apply to sedimentary rock types; there are numerous "bones of classication contentions" also for igneous and metamorphic rock types. Based on the vocabulary specification OneG-E will identify the generic and specific geometric and semantic harmonisation issues and will then "rework" these existing national datasets to make significant progress towards a harmonised dataset - a crucial step towards INSPIRE goals. The standards, architecture and framework developed here can then be "up-scaled" to more detailed levels and progressively deployed for higher resolution geological data. The work on the OneG-E data vocabulary is contributing to enrich and improve the global CGI vocabulary and ontology and will provide a solid base for the description of geology of each EC country when the EC INSPIRE Directive's specification is defined. References Asch, K., Bavec, M., Bergman, S., Perez Cerdan, F., Declercq, P.Y., Janjou, D., Kacer, S., Klicker, M., Nironen, M., Pantaloni, M., Schubert, C. (in preparation): OneGeology-Europe Scientific/Semantic Data Specification and - Generic Specification for Spatial Geological Data in Europe. ECP-2007-GEO-317001 Folk, R.L. (1962): Spectral subdivision of limestone types. In Ham, W.E., ed.: Classification of Carbonate Rocks - A Symposium. American Association of Petroleum Geologists Memoir 1: 62-84 ISO 14688-1 (2002): Geotechnical investigation and testing - Identification and classification of soil - Part 1: Identification and description Pettijohn, F.J. (1975): Sedimentary Rocks.- 3rd ed.; Harper & Row Publishers (New York, Evanston

  1. Sensing at the nanoscale

    NASA Astrophysics Data System (ADS)

    Demming, Anna; Hierold, Christofer

    2013-11-01

    Stampfer C 2013 Graphene-based charge sensors Nanotechnology 24 444001 [6] Nagelli E, Naik R, Xu Y, Gao Y, Zhang M and Dai L 2013 Sensor arrays from multicomponent micropatterned nanoparticles and graphene Nanotechnology 24 444010 [7] Zhang J, Strelcov E and Kolmakov A 2013 Heat dissipation from suspended self-heated nanowires: gas sensor prospective Nanotechnology 24 444009 [8] Morante J R 2013 Chemical to electrical transduction mechanisms from single metal oxide nanowires measurements: response time constant analysis Nanotechnology 24 444004 [9] Stuart E J E, Tschulik K, Omanovi D, Cullen J T, Jurkschat K, Crossley A and Compton R G 2013 Electrochemical detection of commercial silver nanoparticles: identification, sizing and detection in environmental media Nanotechnology 24 444002 [10] Cho H, Felts J R, Yu M-F, Bergman L A, Vakakis A F and King W P 2013 Improved atomic force microscope infrared spectroscopy for rapid nanometer-scale chemical identification Nanotechnology 24 444007 [11] Yoon J-W, Kim H-J, Kim I-D and Lee J-H 2013 Electronic sensitization of C2H5OH response in p-type NiO nanofibers by Fe doping Nanotechnology 24 444005 [12] Guo Y, Su S, Wei X, Zhong Y, Su Y, Huang Q, Fan C and He Y A 2013 Silicon-based electrochemical sensor for highly sensitive, specific, label-free, and real-time DNA detection Nanotechnology 24 444012 [13] Liao Y-J, Shiang Y-C, Chen L-Y, Hsu C-L, Huang C-C and Chang H-T 2013 Detection of adenosine triphosphate through polymerization-induced aggregation of actinconjugated gold/silver nanorods Nanotechnology 24 444003 [14] Korzeniowska B, Nooney R, Wencel D and McDonagh C 2013 Silica nanoparticles for cell imaging and intracellular sensing Nanotechnology 24 442002

  2. High energy neutrinos from astrophysical accelerators of cosmic ray nuclei

    NASA Astrophysics Data System (ADS)

    Anchordoqui, Luis A.; Hooper, Dan; Sarkar, Subir; Taylor, Andrew M.

    2008-02-01

    .1181983223S.P.LaiJ.M.GirartR.CrutcherAstrophys. J.5982003392W.BednarekMon. Not. R. Astron. Soc.3452003847W.BednarekR.J.ProtheroeAstropart. Phys.162002397P.BlasiA.V.OlintoPhys. Rev. D591999023001F.W.SteckerAstropart. Phys.262007398F.W. Stecker, arXiv:astro-ph/0610208.A γ-ray signal from the nearby starburst galaxy NGC253 was reported by the CANGAROO-II Collaboration but their subsequent re-analysis of the data is consistent with the expectation from backgrounds:C.ItohCANGAROO-II CollaborationAstron. Astrophys.3962002L1(Erratum-ibid. 462 (2007) 67)T.A. Thompson, E. Quataert, E. Waxman, A. Loeb, arXiv:astro-ph/0608699.D.J.BirdFly’s Eye CollaborationPhys. Rev. Lett.7119933401D.R.BergmanHiRes CollaborationNucl. Phys. Proc. Suppl.136200440T.Abu-ZayyadHiRes-MIA CollaborationAstrophys. J.5572001686M.NaganoJ. Phys. G181992423V.BerezinskyA.Z.GazizovS.I.GrigorievaPhys. Rev. D742006043005R.U.AbbasiHiRes CollaborationPhys. Rev. Lett.922004151101V.BerezinskyA.Z.GazizovS.I.GrigorievaPhys. Lett. B6122005147V.S.BerezinskyS.I.GrigorievaB.I.HnatykAstropart. Phys.212004617See Fig. 21 in:L.AnchordoquiM.T.DovaA.MariazziT.McCauleyT.PaulS.ReucroftJ.SwainAnn. Phys.3142004145D.AllardE.ParizotE.KhanS.GorielyA.V.OlintoAstron. Astrophys.4432005L29D.AllardE.ParizotA.V.OlintoAstropart. Phys.27200761T.Abu-ZayyadHigh Resolution Fly’s Eye CollaborationAstropart. Phys.232005157P. Sommers, et al., Pierre Auger Collaboration, arXiv:astro-ph/0507150.R.U.AbbasiHiRes CollaborationAstrophys. J.6222005910B.N. Afanasiev, et al., Yakutsk Collaboration, in: M. Nagano (Ed.), Proceedings of the Tokyo Workshop on Techniques for the Study of the Extremely High Energy Cosmic Rays, 1993.J. Knapp, private communication.J.RanftPhys. Rev. D51199564R.S.FletcherT.K.GaisserP.LipariT.StanevPhys. Rev. D5019945710J.EngelT.K.GaisserT.StanevP.LipariPhys. Rev. D4619925013N.N.KalmykovS.S.OstapchenkoA.I.PavlovNucl. Phys. Proc. Suppl.52B19977It is important to stress that the Auger data are still at a preliminary stage and the

  3. New Observations of Comet Hale-Bopp from La Silla

    NASA Astrophysics Data System (ADS)

    1998-10-01

    to the large size of the nucleus, probably 40 - 60 km in diameter, it will be possible to observe this comet with large optical telescopes for many years to come. Information about Hale-Bopp on the web Additional information about Comet Hale-Bopp is available on the web at many sites. Some of the most comprehensive websites may be accessed via the ESO Hale-Bopp site. Notes: [1] Other scientists involved in the long-term radio monitoring of Comet Hale-Bopp are Nicolas Biver (Institute for Astronomy, University of Hawaii, USA), Pierre Colom, Jacques Crovisier, Eric Gérard, Benoit Germain, Emmanuel Lellouch (Observatoire de Paris, France), Didier Despois (Observatoire de Bordeaux, France), Gabriel Paubert (IRAM, Granada, Spain), Raphael Moreno, Joern E. Wink (IRAM, Grenoble, France), John K. Davies (JAC, Hawaii, USA), William R.F. Dent (Royal Observatory, Edinburgh, UK), Hans Rickman, Marcus Gunnarsson (Uppsala Astronomiska Observatorium, Sweden), Per Bergman, Lars E.B. Johansson (OSO, Sweden), Fredrik Rantakyroe (SEST, La Silla), Darek C. Lis, David Mehringer, Dominic Benford, Martin Gardner, Tom G. Phillips (CSO, USA), Heike Rauer (DLR, Berlin, Germany). [2] The figure appears in N. Biver et al. : "Long-term Monitoring of the Outgassing of C/1995 O1 (Hale-Bopp) at Radio Wavelengths", a poster paper presented at the DPS meeting on October 11-16, 1998 (Madison, Wisconsin, USA) and to be published in Vol. 30 of the Bulletin of the American Astronomical Society . How to obtain ESO Press Information ESO Press Information is made available on the World-Wide Web (URL: http://www.eso.org ). ESO Press Photos may be reproduced, if credit is given to the European Southern Observatory.

  4. Solid State Ionics Advanced Materials for Emerging Technologies

    NASA Astrophysics Data System (ADS)

    Chowdari, B. V. R.; Careem, M. A.; Dissanayake, M. A. K. L.; Rajapakse, R. M. G.; Seneviratne, V. A.

    2006-06-01

    . Invited papers. Cathodic properties of Al-doped LiCoO[symbol] prepared by molten salt method Li-Ion batteries / M. V. Reddy, G. V. Subba Rao, B. V. R. Chowdari. Layered ion-electron conducting materials / M. A. Santa Ana, E. Benavente, G. González. LiNi[symbol]Co[symbol]O[symbol] cathode thin-film prepared by RF sputtering for all-solid-state rechargeable microbatteries / X. J. Zhu ... [et al.] -- Contributed papers. Contributed papers. Nanocomposite cathode for SOFCs prepared by electrostatic spray deposition / A. Princivalle, E. Djurado. Effect of the addition of nanoporous carbon black on the cycling characteristics of Li[symbol]Co[symbol](MoO[symbol])[symbol] for lithium batteries / K. M. Begam, S. R. S. Prabaharan. Protonic conduction in TiP[symbol]O[symbol] / V. Nalini, T. Norby, A. M. Anuradha. Preparation and electrochemical LiMn[symbol]O[symbol] thin film by a solution deposition method / X. Y. Gan ... [et al.]. Synthesis and characterization LiMPO[symbol] (M = Ni, Co) / T. Savitha, S. Selvasekarapandian, C. S. Ramya. Synthesis and electrical characterization of LiCoO[symbol] LiFeO[symbol] and NiO compositions / A. Wijayasinghe, B. Bergman. Natural Sri Lanka graphite as conducting enhancer in manganese dioxide (Emd type) cathode of alkaline batteries / N. W. B. Balasooriya ... [et al.]. Electrochemical properties of LiNi[symbol]Al[symbol]Zn[symbol]O[symbol] cathode material synthesized by emulsion method / B.-H. Kim ... [et al.]. LiNi[symbol]Co[symbol]O[symbol] cathode materials synthesized by particulate sol-gel method for lithium ion batteries / X. J. Zhu ... [et al.]. Pulsed laser deposition of highly oriented LiCoO[symbol] and LiMn[symbol]O[symbol] thin films for microbattery applications / O. M. Hussain ... [et al.]. Preparation of LiNi[symbol]Co[symbol]O[symbol] thin films by a sol-gel method / X. J. Zhu ... [et al.]. Electrochemical lithium insertion into a manganese dioxide electrode in aqueous solutions / M. Minakshi ... [et al.]. AC impedance

  5. EDITORIAL: Special issue on applied neurodynamics: from neural dynamics to neural engineering Special issue on applied neurodynamics: from neural dynamics to neural engineering

    NASA Astrophysics Data System (ADS)

    Chiel, Hillel J.; Thomas, Peter J.

    2011-12-01

    -LXIII (London: Royal Society) Ralph T C and Pryde G J 2010 Progress in Optics vol 54, ed E Wolf (New York: Elsevier) pp 209-79 (arXiv:1103.6071) Rashevsky N 1960 Mathematical Biophysics: Physico-Mathematical Foundations of Biology vol 1 3rd edn (New York: Dover) pp 375-462 (first edition 1938) Rinzel J and Ermentrout G B 1989 Analysis of neuronal excitability and oscillations Methods in Neuronal Modeling ed C Koch and I Segev (Cambridge, MA: MIT Press) pp 135-69 Rosin B, Nevet A, Elias S, Rivlin-Etzion M, Israel Z and Bergman H 2007 Physiology and pathophysiology of the basal ganglia-thalamo-cortical networks Parkinsonism Relat. Disord. 13 S437-9 Spardy L E, Markin S N, Shevtsova N A, Prilutsky B I, Rybak I A and Rubin J E 2011a A dynamical systems analysis of afferent control in a neuromechanical model of locomotion: I. Rhythm generation J. Neural Eng. 8 065003 Spardy L E, Markin S N, Shevtsova N A, Prilutsky B I, Rybak I A and Rubin J E 2011b A dynamical systems analysis of afferent control in a neuromechanical model of locomotion: II. Phase asymmetry J. Neural Eng. 8 065004 Steane A 1998 Quantum computing Rep. Prog. Phys. 61 117-73 Strogatz S H 1994 Nonlinear Dynamics and Chaos: with Applications to Physics, Biology, Chemistry, and Engineering (Cambridge, MA: Perseus) Thomas P J 2011 A lower bound for the first passage time density of the suprathreshold Ornstein-Uhlenbeck process J. Appl. Probab. 48 420-34 White J A, Rubinstein J T and Kay A R 2000 Channel noise in neurons Trends Neurosci. 23 131-7 Wilson H R and Cowan J D 1972 Excitatory and inhibitory interactions in localized populations of model neurons Biophys. J. 12 1-24 Wilson H R and Cowan J D 1973 A mathematical theory of the functional dynamics of cortical and thalamic nervous tissue Biol. Cybern. 13 55-80